阅读说明：本技术 蓄热组合物、蓄热部件、电子设备及蓄热部件的制造方法 (Heat storage composition, heat storage member, electronic device, and method for producing heat storage member ) 是由 三井哲朗 佐藤尚俊 中山亚矢 松下卓人 八田政宏 川上浩 于 2020-03-19 设计创作，主要内容包括：本发明的课题在于提供一种具有优异滞然性的蓄热组合物及具有优异滞然性的蓄热部件。并且,本发明的课题在于提供一种具有蓄热部件的电子设备及蓄热部件的制造方法。本发明的蓄热组合物含有蓄热材料及阻燃剂,并满足特定的条件A。本发明的蓄热部件含有蓄热材料及阻燃剂,并满足特定的条件C。(The present invention addresses the problem of providing a heat-accumulative composition having excellent flame retardancy and a heat-accumulative member having excellent flame retardancy. Another object of the present invention is to provide an electronic device having a heat storage member and a method for manufacturing the heat storage member. The heat-accumulative composition of the present invention contains a heat-accumulative material and a flame retardant, and satisfies a specific condition A. The heat storage member of the present invention contains a heat storage material and a flame retardant, and satisfies specific condition C.)

1. A heat-accumulative composition comprising a heat-accumulative material and a flame retardant satisfying the following condition A,

condition a: the gas generation temperature Tr of the flame retardant obtained by the following measurement method A1 was lower than the gas generation temperature Ta of the following specific composition obtained by the following measurement method A2,

measurement method a 1: identifying the type and content of the flame retardant contained in the heat-accumulative composition, measuring the change in weight of the flame retardant caused by heating using a thermogravimetric differential thermal analyzer, deriving a relational expression between the temperature T represented by the following formula (A1) and the weight loss rate Δ ma (T) of the flame retardant based on the measurement result,

Δma(T)＝(ma₀-ma(T))/ma₀ (A1)

in formula (A1), ma (T) represents the weight of the flame retardant at temperature T, ma₀A temperature at which the weight loss rate Δ ma (T) of the flame retardant reaches 2 mass% is determined as the gas generation temperature Tr of the flame retardant using the formula (A1),

measurement method a 2: measuring a change in weight of the heat-accumulative composition caused by heating using a thermogravimetric differential thermal analyzer, deriving a relational expression between the temperature T represented by the following formula (A2) and the weight loss rate Deltam 1(T) of the heat-accumulative composition based on the measurement result,

Δm1(T)＝(m1₀-m1(T))/(m1₀) (A2)

in formula (A2), m1(T) represents the weight of the heat-accumulative composition at temperature T, m1₀Represents the weight of the heat-accumulative composition before heating,

and identifying the type and content of the solvent having a boiling point of 100 ℃ or lower contained in the heat-accumulative composition, and as a result of the measurement, measuring the change in weight of the solvent caused by heating using a thermogravimetric differential thermal analyzer in the case where the heat-accumulative composition contains the solvent, and deriving a relational expression between the temperature T represented by the following formula (A3) and the weight reduction rate Δ mb (T) of the solvent based on the measurement result,

Δmb(T)＝(mb₀-mb(T))/(mb₀) (A3)

in formula (A3), mb (T) represents the weight of the solvent at temperature T, mb₀Represents the weight of the solvent before heating,

deriving a relational expression between a temperature T represented by the following formula (A4) and a weight loss rate Deltamx (T) of a specific composition obtained by removing the flame retardant and the solvent from the heat-accumulative composition,

Δmx(T)＝(100*Δm1(T)-a*Δma(T)-b*Δmb(T))/(100-a-b)(A4)

in formula (a4), a represents the ratio of the content of the flame retardant to the total mass of the heat-accumulative composition in mass%, b represents the ratio of the content of the solvent to the total mass of the heat-accumulative composition in mass%, Δ ma (t) represents the weight loss rate of the flame retardant determined in the measuring method a1,

the temperature at which the weight loss rate Δ mx (T) of the specific composition reaches 2 mass% is determined using the formula (A4), and is used as the gas generation temperature Ta of the specific composition,

the unit of the temperature T, the gas generation temperature Tr, and the gas generation temperature Ta is ℃.

2. The heat-accumulative composition according to claim 1,

the heat storage material contains paraffin.

3. The heat-accumulative composition according to claim 1 or 2,

the content of the heat-accumulative material is 70% by mass or more relative to the total mass of the heat-accumulative composition.

4. The heat-accumulative composition according to any one of claims 1 to 3,

the content of the flame retardant is 0.1 mass% or more relative to the content of the heat storage material.

5. The heat-accumulative composition according to any one of claims 1 to 4,

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and trimethyl phosphate.

6. The heat-accumulative composition according to any one of claims 1 to 5,

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate and ammonium dihydrogen phosphate.

7. The heat-accumulative composition according to any one of claims 1 to 6,

the gas generation temperature Tr of the flame retardant is above 100 ℃.

8. A thermal storage composition according to any one of claims 1 to 7 which is in the form of a sheet.

9. A heat storage member which comprises a heat storage material and a flame retardant and satisfies the following condition C,

condition C: the gas generation temperature Tr of the flame retardant obtained by the following measurement method C1 was lower than the gas generation temperature Tc of the following specific member obtained by the following measurement method C2,

measurement method C1: identifying the type and content of the flame retardant contained in the heat storage member, measuring the change in weight of the flame retardant caused by heating using a thermogravimetric differential thermal analyzer, deriving a relational expression between the temperature T represented by the following formula (C1) and the weight reduction rate Δ ma (T) of the flame retardant based on the measurement result,

Δ ma(T)＝(ma₀-ma(T))/(ma₀) (C1)

in the formula (C1), ma (T) represents the weight of the flame retardant at temperature T, ma₀A temperature at which the weight loss rate Δ ma (T) of the flame retardant reaches 2 mass% is determined as the gas generation temperature Tr of the flame retardant using the formula (C1),

measurement method C2: measuring a change in weight of the heat storage member due to heating using a thermogravimetric differential thermal analysis apparatus, deriving a relational expression between a temperature T represented by the following expression (C2) and a weight loss rate Deltam 3(T) of the heat storage member based on the measurement result,

Δm3(T)＝(m3₀-m3(T))/(m3₀) (C2)

in the formula (C2), m3(T) represents the weight of the thermal storage member at temperature T, m3₀Represents the weight of the heat storage member before heating,

and identifying the type and content of the solvent having a boiling point of 100 ℃ or lower contained in the heat storage member, and as a result of the measurement, measuring a change in weight of the solvent caused by heating using a thermogravimetric differential thermal analysis device in the case where the heat storage member contains the solvent, and deriving a relational expression between the temperature T represented by the following expression (C3) and the weight reduction rate Δ mb (T) of the solvent based on the measurement result,

Δmb(T)＝(mb₀-mb(T))/(mb₀) (C3)

in the formula (C3), mb (T) represents the weight of the solvent at the temperature T, mb₀Represents the weight of the solvent before heating,

deriving a relational expression between a temperature T represented by the following expression (C4) and a weight loss rate Deltamz (T) of a specific member obtained by removing the flame retardant and the solvent from the heat-storage member,

Δmz(T)＝(100*Δm3(T)-a*Δma(T)-b*Δmmb(T))/(100-a-b)(C4)

in the formula (C4), a represents the ratio of the content of the flame retardant to the total mass of the heat storage member in mass%, b represents the ratio of the content of the solvent to the total mass of the heat storage member in mass%, Δ ma (t) represents the weight reduction rate of the flame retardant determined in the measurement method C1,

the temperature at which the weight loss rate Δ mz (t) of the specific member reaches 2 mass% is determined using the formula (C4), and is used as the gas generation temperature Tc of the specific member,

the unit of the temperature T, the gas generation temperature Tr, and the gas generation temperature Ta is ℃.

10. The thermal storage member according to claim 9,

the heat storage member has a heat storage layer containing the heat storage material and a protective layer,

at least one of the heat storage layer and the protective layer contains the flame retardant.

11. The thermal storage member according to claim 9 or 10,

the heat storage material contains paraffin.

12. The thermal storage member according to any one of claims 9 to 11,

the content of the heat storage material is 70 mass% or more with respect to the total mass of the heat storage member.

13. The thermal storage member according to any one of claims 9 to 12,

the content of the flame retardant is 0.1 mass% or more relative to the content of the heat storage material.

14. The thermal storage member according to any one of claims 9 to 13,

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and trimethyl phosphate.

15. The thermal storage member according to any one of claims 9 to 14,

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate and ammonium dihydrogen phosphate.

16. The thermal storage member according to any one of claims 9 to 15, wherein,

the gas generation temperature Tr of the flame retardant is above 100 ℃.

17. The thermal storage member according to claim 10,

the protective layer contains a flame retardant.

18. The thermal storage member according to claim 10 or 17,

the protective layer has a crosslinked structure.

19. The thermal storage member according to any one of claims 10, 17 and 18,

the thickness of the protective layer is 10 μm or less.

20. An electronic device having at least one selected from the group consisting of the heat storage composition described in any one of claims 1 to 8 and the heat storage member described in any one of claims 9 to 19.

21. A method for producing a heat storage member according to any one of claims 10 and 17 to 19,

the protective layer is disposed on at least one surface of the heat storage layer.

Technical Field

The present invention relates to a heat storage composition, a heat storage member, an electronic device, and a method for producing a heat storage member.

Background

In electronic devices, buildings, automobiles, exhaust heat utilization systems, and other devices, heat storage members are used which store heat from a heat generating body and suppress an increase in the overall temperature. The heat storage member contains a heat storage material that functions as a material capable of storing heat generated outside the heat storage layer.

For example, patent document 1 discloses the following invention: (A) an acrylic copolymer having a reactive functional group and a specific molecular weight; (B) a compound having a functional group that reacts with the acrylic copolymer and chain-extends; (C) a heat-accumulative acrylic resin composition having, as a matrix, an acrylic copolymer having a specific molecular weight and no reactive functional group in a molecular chain, in a specific content; and a sheet-like molded article obtained by molding and curing the heat-accumulative acrylic resin composition into a sheet form (see claims 1 and 4).

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 5192138

Disclosure of Invention

Technical problem to be solved by the invention

As described in patent document 1, the conventional heat storage member contains a material which is easily combustible, such as paraffin, as a heat storage material, and therefore, in order to improve flame retardancy, a flame retardant may be further contained.

As a method for suppressing combustion of the heat-accumulative composition, heat-accumulative sheet and heat-accumulative material (in the present specification, these are also collectively referred to as "heat-accumulative material") containing such heat-accumulative material, there are two methods of improving ignition resistance for suppressing ignition of heat-accumulative material and improving flame retardancy (combustion delay property) for suppressing expansion of combustion range in heat-accumulative material. The present inventors have further studied the flame retardancy of conventional heat-accumulative materials containing a flame retardant from the above viewpoints, and as a result, have found that there is room for further improvement in the flame retardancy of such heat-accumulative materials.

The present invention has been made in view of the above circumstances. The present invention addresses the problem of providing a heat-accumulative composition having excellent flame retardancy and a heat-accumulative member having excellent flame retardancy.

Another object of the present invention is to provide an electronic device having a heat storage member, and a method for manufacturing the heat storage member.

Means for solving the technical problem

Specific embodiments for solving the problem of the present invention include the following.

[ 1] A heat-accumulative composition,

which contains a heat-accumulative material and a flame retardant and satisfies the condition A described later.

[ 2] the heat-accumulative composition according to [ 1],

the heat-accumulative material contains paraffin.

[ 3] the heat-accumulative composition according to [ 1] or [ 2], wherein,

the content of the heat-accumulative material is 70% by mass or more based on the total mass of the heat-accumulative composition.

[ 4] the heat-accumulative composition according to any one of [ 1] to [ 3],

the content of the flame retardant is 0.1 mass% or more relative to the content of the heat-accumulative material.

[ 5] the heat-accumulative composition according to any one of [ 1] to [ 4],

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and trimethyl phosphate.

[ 6] the heat-accumulative composition according to any one of [ 1] to [ 5],

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate and ammonium dihydrogen phosphate.

[ 7] the heat-accumulative composition according to any one of [ 1] to [ 6],

the flame retardant has a gas generation temperature Tr of 100 ℃ or higher.

[ 8 ] the heat-accumulative composition according to any one of [ 1] to [ 7],

it is in the form of a sheet.

[ 9 ] A heat storage member which is,

which contains a heat-accumulative material and a flame retardant and satisfies the condition C described later.

[ 10 ] the heat storage member according to [ 9 ], wherein,

the heat storage member has a heat storage layer containing the heat storage material and a protective layer,

at least one of the heat storage layer and the protective layer contains the flame retardant.

[ 11 ] the thermal storage member according to [ 9 ] or [ 10 ], wherein,

the heat-accumulative material contains paraffin.

[ 12 ] the heat storage member according to any one of [ 9 ] to [ 11 ], wherein,

the content of the heat storage material is 70 mass% or more with respect to the total mass of the heat storage member.

[ 13 ] the heat storage member according to any one of [ 9 ] to [ 12 ], wherein,

the content of the flame retardant is 0.1 mass% or more relative to the content of the heat-accumulative material.

[ 14 ] the heat storage member according to any one of [ 9 ] to [ 13 ], wherein,

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and trimethyl phosphate.

[ 15 ] the heat storage member according to any one of [ 9 ] to [ 14 ], wherein,

the flame retardant contains at least one selected from the group consisting of diammonium hydrogen phosphate and ammonium dihydrogen phosphate.

The heat storage member according to any one of [ 9 ] to [ 15 ], wherein,

the flame retardant has a gas generation temperature Tr of 100 ℃ or higher.

[ 17 ] the heat storage member according to [ 10 ], wherein,

the protective layer contains a flame retardant.

[ 18 ] the thermal storage member according to [ 10 ] or [ 17 ], wherein,

the protective layer has a crosslinked structure.

[ 19 ] the heat storage member according to any one of [ 10 ], [ 17 ] and [ 18 ], wherein,

the thickness of the protective layer is 10 μm or less.

[ 20 ] an electronic apparatus is provided,

which has at least one selected from the group consisting of the heat-accumulative composition according to any one of [ 1] to [ 8 ] and the heat-accumulative member according to any one of [ 9 ] to [ 19 ].

[ 21 ] A method for producing a heat storage member,

the method for producing a heat storage member according to any one of [ 10 ] and [ 17 ] to [ 19 ],

the protective layer is disposed on at least one surface of the heat storage layer.

Effects of the invention

According to the present invention, a heat-accumulative composition having excellent flame retardancy, a heat-accumulative sheet having excellent flame retardancy, and a heat-accumulative member having excellent flame retardancy can be provided. Further, according to the present invention, it is possible to provide an electronic device having a heat storage member and a method for manufacturing the heat storage member.

Detailed Description

The present invention will be described in detail below.

Further, according to the exemplary embodiment of the present invention, the description of the configuration elements of the embodiment of the present invention can be made, but the present invention is not limited to such an embodiment.

In the present specification, the numerical ranges expressed by using the "to" indicate ranges including the numerical values described before and after the "to" as the minimum value and the maximum value, respectively. In the numerical ranges recited in the present specification, the upper limit or the lower limit recited in a certain numerical range may be replaced with the upper limit or the lower limit recited in another numerical range recited in a stepwise manner. In the numerical ranges described in the present specification, the upper limit or the lower limit described in a certain numerical range may be replaced with values shown in the examples.

In the numerical ranges recited in the present specification, the upper limit or the lower limit recited in one numerical range may be replaced with the upper limit or the lower limit recited in another numerical range recited in a stepwise manner. In the numerical ranges described in the present specification, the upper limit or the lower limit of the numerical range may be replaced with the values shown in the examples.

In the present specification, "mass%" and "weight%" have the same meaning, and "parts by mass" and "parts by weight" have the same meaning.

In the present specification, a combination of two or more preferred embodiments is a more preferred embodiment.

In the present specification, the amount of each component in the composition or layer means the total amount of a plurality of substances present in the composition unless otherwise specified, in the case where a plurality of substances corresponding to each component are present in the composition.

The heat-accumulative composition of the present invention comprises a heat-accumulative material and a flame retardant, and satisfies the following condition A: the gas generation temperature Tr of the flame retardant obtained by the measurement method a1 was lower than the gas generation temperature Ta of the specific composition (described later) obtained by the measurement method a 2.

The heat storage member of the present invention contains a heat storage material and a flame retardant, and satisfies the following condition C: the gas generation temperature Tr of the flame retardant obtained by the measurement method C1 is lower than the gas generation temperature Tc of a specific member (described later) obtained by the measurement method C2.

In the present specification, the above-mentioned condition a and the above-mentioned condition C are also collectively referred to as "specific conditions".

The detailed mechanism and the like of obtaining the effects of the present invention by the heat-accumulative material satisfying the above-mentioned specific conditions are not clear, but the present inventors presume that the flame retardancy of the heat-accumulative material is improved for the following reasons.

As a typical process involving combustion by flame, there is a process in which: (a) the proximity of the heating element (e.g., flame) increases the temperature of the material; (b) generating a combustible gas (radical) from the material having the increased temperature; (c) oxygen in the air reacts with the combustible gas to ignite; and (d) maintaining the temperature of the material by (c) and repeating (a), (b) and (c). In contrast, it is presumed that: in the heat storage material of the present invention containing a flame retardant satisfying the above-described specific conditions, the flame retardant is decomposed at a temperature lower than the temperature at which the heat storage material is decomposed to generate a combustible gas, and the anti-inflammatory gas reacts with (diminishes the inflammation of) the combustible gas generated by the decomposition of the heat storage material, thereby suppressing the expansion of the combustion range in the heat storage material.

The heat-accumulative composition of the present invention, the heat-accumulative sheet of the present invention and the heat-accumulative member of the present invention will be described in detail hereinafter.

[ Heat-accumulative composition ]

The heat-accumulative composition of the present invention satisfies the following condition A: the gas generation temperature Tr of the flame retardant obtained by the measurement method a1 was lower than the gas generation temperature Ta of the specific composition obtained by the measurement method a 2.

Here, the "specific composition" refers to a composition obtained by removing the flame retardant and the solvent having a boiling point of 100 ℃ or lower (hereinafter, also referred to as "specific solvent") from the heat-accumulative composition.

[ Condition A ]

< measurement method A1>

The measurement method a1 for obtaining the gas generation temperature Tr of the flame retardant was as follows.

The kind and content of the flame retardant contained in the heat-accumulative composition were identified.

The method of identification may be a known method, and may be identified according to the type of the flame retardant and the components contained in the heat-accumulative composition other than the flame retardant, and is not particularly limited, and examples thereof include: a method of measuring by chromatography, Nuclear Magnetic Resonance (NMR) or infrared spectroscopy (IR) after the heat-accumulative composition is immersed in a solvent (e.g., an organic solvent) to extract the heat-accumulative material; and a method of measuring a cross section of a film cut obliquely to the thickness direction by a Secondary Ion Mass Spectrometry (SIMS) and identifying elements, constituent molecules, and/or ions constituting the film when the heat storage composition is in the form of a film.

Next, with respect to the identified flame retardants, the weight change caused by heating was measured using a thermogravimetric Differential Thermal Analyzer (TG-DTA: Thermogravimeter-Differential Thermal Analyzer).

The measurement of the weight change due to heating of the flame retardant, the specific solvent described later, and the heat storage material described later can be performed using a known TG-DTA, and can be performed, for example, under a nitrogen atmosphere and under a temperature rise condition of 10 ℃.

From the obtained measurement results, a relational expression between the temperature T (. degree. C.) represented by the following expression (A1) and the weight loss rate Δ ma (T) of the flame retardant was derived.

Δma(T)＝(ma₀-ma(T))/(ma₀) (A1)

In the formula (A1), ma (T) represents the weight of the flame retardant at a temperature T (. degree. C.), and ma₀The weight of the flame retardant before heating (initial weight) is shown.

Further, the weight before heating of each material used in the measurement test using the TG-DTA can be measured, for example, before the heat treatment using the TG-DTA.

When the heat-accumulative composition contains two or more flame retardants, the weight loss rate Δ ma (t) of the flame retardant measured by measuring method a1 is calculated as the sum of the products of the weight loss rates of the respective flame retardants alone obtained by using TG-DTA and the ratio of the content of the respective flame retardants to the total content of the flame retardant.

For example, the heat-accumulative composition comprises two flame retardants consisting of flame retardant 1 and flame retardant 2, wherein the respective flame retardants are a1 and a2 in terms of the total content of the flame retardants, and when the respective flame retardants alone are reduced in weight by Δ ma1(T) and Δ ma2(T) at a temperature T (. degree. C.), the reduced weight by Δ ma (T) of the flame retardant obtained by measuring method 1 is obtained by the following formula.

Δma(T)＝a1*Δma1(T)+a2*Δma2(T)

Next, the temperature at which the weight loss rate Δ ma (t) of the flame retardant reaches 2 mass% was calculated using formula (a1), and the gas generation temperature Tr (c) of the flame retardant was obtained.

< measurement method A2>

Measurement method a2 for obtaining the gas generation temperature Ta of a specific composition is as follows.

First, the weight change caused by heating of the heat-accumulative composition was measured using TG-DTA. For the measurement of the heat-accumulative composition using TG-DTA, as described above.

From the obtained measurement results, a relational expression between the temperature T (deg.c) represented by the following expression (a2) and the weight loss rate Δ m1(T) of the heat-accumulative composition was derived.

Δm1(T)＝(m1₀-m1(T))/(m1₀) (A2)

In the formula (A2), m1(T) represents the weight of the heat-accumulative composition at a temperature T (. degree. C.) and m1₀Represents the weight of the heat-accumulative composition before heating.

Then, the kind and content of the specific solvent contained in the heat-accumulative composition were identified. Examples of the identification method include the following known methods: a method of quantifying organic substances by Gas Chromatography-Mass spectrometry (GC-MS: Gas Chromatography-Mass spectrometry), and quantifying inorganic substances by ion Chromatography, and the like.

In the case where the heat-accumulative composition contains a specific solvent, TG-DTA was used to measure the weight change caused by heating with respect to the specific solvent identified. For the measurement of a specific solvent using TG-DTA, as described above.

From the obtained measurement results, a relational expression between the temperature T (c) represented by the following expression (a3) and the weight loss rate Δ mb (T) of the specific solvent was derived.

Δmb(T)＝(mb₀-mb(T))/(mb₀) (A3)

In the formula (A3), mb (T) represents the weight of a specific solvent at a temperature T (. degree. C.), mb₀Represents the weight of the specific solvent before heating.

When the heat-accumulative composition contains two or more specific solvents, the weight-loss ratio Δ mb (t) of the specific solvent measured by the measuring method a2 is calculated as the sum of the weight-loss ratios of the individual specific solvents obtained by TG-DTA multiplied by the ratio of the content of each specific solvent to the total content of the specific solvents, similarly to the weight-loss ratio Δ ma (t) of the flame retardant measured by the measuring method a 1.

Next, a relational expression between the temperature T (° c) represented by the following expression (a4) and the weight loss rate Δ mx (T) of the specific composition is derived.

Δmx(T)＝(100*Δm1(T)-a*Δma(T)-b*Δmb(T))/(100-a-b)(A4)

In formula (a4), a represents the ratio (% by mass) of the content of the flame retardant (the total content thereof in the case where two or more flame retardants are present) to the total mass of the heat-accumulative composition. b represents a ratio (% by mass) of the content of the specific solvent (in the case where two or more specific solvents are present, the total content thereof) to the total mass of the heat-accumulative composition. Δ ma (t) represents the weight loss rate of the flame retardant determined in measurement method a 1.

The temperature at which the weight loss rate Δ mx (t) of the specific composition reached 2 mass% was determined using the formula (a4), and this was taken as the gas generation temperature Ta (deg.c) of the specific composition.

Comparing the gas generation temperature Tr of the flame retardant obtained by the above-mentioned measurement method A1 with the gas generation temperature Ta of the specific composition obtained by the above-mentioned measurement method A2, the heat-accumulative composition satisfies the condition A in the case where the gas generation temperature Tr of the flame retardant is lower than the gas generation temperature Ta of the specific composition (Ta-Tr > 0).

Presumably, it is: when the heat-accumulative composition satisfies the condition A, the anti-inflammatory gas generated first by the decomposition of the flame retardant at the time of temperature rise reacts with the combustible gas generated after the decomposition of the heat-accumulative material to suppress the combustion of the heat-accumulative composition, thereby improving the flame retardancy of the heat-accumulative composition.

The heat-accumulative composition of the present invention satisfying condition A is excellent in flame resistance and flame retardance. The detailed mechanism and the like of the improvement of the ignition resistance of the heat-accumulative composition when the condition A is satisfied are not clear, but the same reason as the improvement of the ignition resistance when the condition A is satisfied is presumed.

The gas generation temperature Tr of the flame retardant in the heat-accumulative composition and the gas generation temperature Ta of the specific composition are not particularly limited as long as they satisfy the condition a.

From the viewpoint of improving the stability of the heat-accumulative composition during use, the gas generation temperature Tr of the flame retardant is preferably 100 ℃ or higher, and more preferably 120 ℃ or higher. The upper limit of the gas generation temperature Tr of the flame retardant is not particularly limited as long as it is lower than the gas generation temperature Ta of the specific composition, but is preferably a temperature sufficiently lower than the temperature at which the heat-accumulative composition is heated during combustion, and more preferably 300 ℃.

From the viewpoint of improving the stability of the heat-accumulative composition during use, the gas generation temperature Ta of the specific composition is preferably 100 ℃ or higher, and more preferably 120 ℃ or higher.

From the viewpoint of increasing the gas generation temperature Ta of the specific member to improve the stability of the heat-accumulative composition during use, the heat-accumulative composition preferably contains substantially no low-molecular-weight compound. The "low-molecular-weight compound" means a compound having a molecular weight of 150 or less, and "substantially not contained" means that the content is 1 mass% or less with respect to the total mass of the heat-accumulative composition.

From the viewpoint of further improving the storage stability of the heat-accumulative composition, the difference between the gas generation temperature Tr of the flame retardant and the gas generation temperature Ta of the specific composition is preferably 100 ℃ or less, and preferably 50 ℃ or less.

[ composition ]

The heat-accumulative material and flame retardant contained in the heat-accumulative composition will be described in more detail below.

The heat-accumulative composition is not particularly limited in its composition, structure and form as long as it contains a heat-accumulative material and a flame retardant and satisfies the condition A.

The heat-accumulative material contained in the heat-accumulative composition may be in the form of being contained in microcapsules or may be in the form of not being contained in microcapsules.

In the heat-accumulative composition, it is preferable that at least a part of the heat-accumulative material is contained in the microcapsule from the viewpoint that the heat-accumulative material can stably exist in a phase state corresponding to the temperature, and that the heat-accumulative material which becomes liquid at high temperature can be prevented from leaking out of the heat-accumulative composition, and that the heat-accumulative material can maintain the heat-accumulative capacity of the heat-accumulative composition without contaminating the members around the heat-accumulative composition.

Hereinafter, the heat-accumulative material contained in the heat-accumulative composition will be specifically described by taking microcapsules as an example.

< microcapsules (Heat-accumulative Material) >

The microcapsules contained in the heat storage composition have a core portion and a wall portion for containing a core material (containing a substance (also referred to as an inclusion component)) forming the core portion, the wall portion being also referred to as "capsule wall".

(core material)

The microcapsules contain an heat-storing material as a core material (inner pack component).

Since at least a part of the heat storage material is contained in the microcapsule, the heat storage material can stably exist in a phase state according to the temperature.

-heat storage material-

The heat storage material may be appropriately selected from materials that can repeat a phase change between a solid phase and a liquid phase in accordance with a change in the state of dissolution and coagulation in accordance with a change in temperature, depending on a target object (for example, a heating element) such as heat control or heat use, a purpose, and the like.

The phase change of the heat storage material is preferably based on the melting point of the heat storage material itself.

The heat storage material may be, for example, any of a material capable of storing heat generated outside the heat storage composition as sensible heat and a material capable of storing heat generated outside the heat storage composition as latent heat (hereinafter, also referred to as "latent heat storage material"). The heat storage material is preferably a material capable of releasing stored heat.

Among them, the latent heat storage material is more preferably a latent heat storage material from the viewpoint of control of exchangeable heat amount, control speed of heat, and magnitude of heat amount.

Latent heat storage material

The latent heat storage material is a material that can exchange heat based on latent heat by using heat generated outside the heat storage composition as latent heat and repeating a change between dissolution and solidification using a melting point determined by the material as a phase change temperature.

The latent heat storage material can store heat and dissipate heat in accordance with a solid-liquid phase change by using the heat of solution at the melting point and the heat of solidification at the freezing point.

The latent heat storage material can be selected from compounds having a melting point and capable of undergoing a phase change.

As the latent heat storage material, for example, ice (water) may be mentioned; aliphatic hydrocarbons such as paraffins (e.g., isoparaffins and normal paraffins); an inorganic salt; organic acid ester compounds such as tricaprylin (caprylic/capric) glyceride, methyl myristate (melting point 16-19 ℃), isopropyl myristate (melting point 167 ℃) and dibutyl phthalate (melting point-35 ℃); aromatic hydrocarbons such as an alkylnaphthalene compound (melting point 67 to 70 ℃ C.), a diarylalkane compound (melting point less than-50 ℃ C.), a 1-phenyl-1-ditolylethane compound (melting point less than-50 ℃ C.), an alkylbiphenyl compound (melting point 11 ℃ C.), a triarylmethane compound, an alkylbenzene compound, a benzylnaphthalene compound, a diarylalkylene compound, and an arylperylene compound; natural animal and vegetable oils such as camellia oil, soybean oil, corn oil, cottonseed oil, rapeseed oil, olive oil, coconut oil, castor oil and fish oil; and natural high-boiling fractions such as mineral oil.

Among the latent heat storage materials, paraffin is preferred from the viewpoint of exhibiting excellent heat storage properties.

The paraffin wax is preferably an aliphatic hydrocarbon having a melting point of 0 ℃ or higher, and more preferably an aliphatic hydrocarbon having a melting point of 0 ℃ or higher and 14 or more carbon atoms.

Examples of the aliphatic hydrocarbon having a melting point of 0 ℃ or higher include tetradecane (melting point 6 ℃), pentadecane (melting point 10 ℃), hexadecane (melting point 18 ℃), heptadecane (melting point 22 ℃), octadecane (melting point 28 ℃), nonadecane (melting point 32 ℃), eicosane (melting point 37 ℃), heneicosane (melting point 40 ℃), docosane (melting point 44 ℃), tricosane (melting point 48 to 50 ℃), tetracosane (melting point 52 ℃), pentacosane (melting point 53 to 56 ℃), heptacosane (melting point 60 ℃), octacosane (melting point 65 ℃), nonacosane (melting point 63 to 66 ℃) and triacontane (melting point 64 to 67 ℃).

The inorganic salt is preferably an inorganic hydrate salt, and examples thereof include a hydrate of an alkali metal chloride (e.g., sodium chloride 2 hydrate), a hydrate of an alkali metal acetate (e.g., sodium acetate hydrate), a hydrate of an alkali metal sulfate (e.g., sodium sulfate hydrate), a hydrate of an alkali metal thiosulfate (e.g., sodium thiosulfate hydrate), a hydrate of an alkaline earth metal sulfate (e.g., calcium sulfate hydrate), and a hydrate of an alkali metal chloride (e.g., calcium chloride hydrate).

The melting point of the heat storage material can be selected according to the purpose, such as the type of heating element that generates heat, the heating temperature of the heating element, the temperature after cooling or the holding temperature, and the cooling method. By appropriately selecting the melting point, for example, the temperature of the heat generating body that generates heat can be stably maintained at an appropriate temperature without being excessively cooled.

The heat storage material is preferably selected mainly from materials having a melting point at the center temperature of a target temperature region (for example, the operating temperature of a heat generating body; hereinafter, also referred to as "heat control region").

The selection of the thermal storage material can be selected in accordance with the melting point of the thermal storage material in combination with the thermal control region. The heat control region may be set according to the use (for example, the kind of the heat generating body).

Specifically, the melting point of the selected heat storage material differs depending on the heat control region, but a material having the following melting point can be appropriately selected as the heat storage material. In the case where the use is an electronic device (in particular, a small-sized or portable or handheld electronic device), then these heat storage materials are suitable.

(1) Among the above heat storage materials (preferably latent heat storage materials), a heat storage material having a melting point of 0 ℃ or more and 80 ℃ or less is preferable.

When a heat storage material having a melting point of 0 ℃ or higher and 80 ℃ or lower is used, a material having a melting point of less than 0 ℃ or more than 80 ℃ is not included in the heat storage material. Among materials having a melting point of less than 0 ℃ or more than 80 ℃, a material in a liquid state can be used as a solvent in combination with a heat storage material.

(2) Among the above, the heat-accumulative material having a melting point of 10 ℃ or more and 70 ℃ or less is more preferable.

When a heat storage material having a melting point of 10 ℃ or more and 70 ℃ or less is used, a material having a melting point of less than 10 ℃ or more than 70 ℃ is not included in the heat storage material. Among materials having a melting point of less than 10 ℃ or more than 70 ℃, a material in a liquid state can be used as a solvent in combination with a heat storage material.

(3) Further, the heat-accumulative material having a melting point of 15 ℃ or higher and 50 ℃ or lower is more preferable.

When a heat storage material having a melting point of 15 ℃ or more and 50 ℃ or less is used, a material having a melting point of less than 15 ℃ or more than 50 ℃ is not included in the heat storage material. Among materials having a melting point of less than 15 ℃ or more than 50 ℃, a material in a liquid state can be used as a solvent in combination with a heat storage material.

The heat-accumulative material may be used alone or in combination of two or more. By using one heat-accumulative material alone or a plurality of heat-accumulative materials having different melting points, the temperature range and the accumulative amount of heat accumulative material exhibiting heat accumulative capacity can be adjusted according to the application.

The temperature range in which heat can be stored can be expanded by mixing two other heat storage materials having melting points at the center temperature or higher and the center temperature or lower, with the heat storage material having a melting point at the center temperature at which the heat storage effect of the heat storage material is to be obtained as the center. Specifically, when the case where paraffin is used as the heat storage material is taken as an example, paraffin a having a melting point at a core temperature at which the heat storage effect of the heat storage material is to be obtained is used as the core material, and paraffin a and two other kinds of paraffin having a carbon number greater than or less than that of paraffin a are mixed, whereby the material can also be designed to have a wide temperature region (heat control region).

The content of the paraffin having a melting point at the core temperature at which the heat storage effect is to be obtained is preferably 80 mass% or more, more preferably 90 mass% or more, and still more preferably 95 mass% or more, based on the total mass of the heat storage material.

On the other hand, depending on the application of the electronic device and the like, the heat-accumulative composition contains substantially one heat-accumulative material. If the heat storage material used is substantially one, the heat storage composition is filled with the heat storage material at a high purity, and therefore, the heat absorption of the heat generating element by the electronic device is good. Here, the substantially single heat storage material means that the content of the heat storage material having the largest content among the plurality of heat storage materials contained in the heat storage composition is 95 mass% or more, preferably 98 mass% or more, with respect to the total mass of all the heat storage materials contained in the heat storage composition. The upper limit is not particularly limited as long as it is 100 mass% or less.

For example, when paraffin is used as the latent heat storage material, one kind of paraffin may be used alone, or two or more kinds may be used in combination. When a plurality of types of paraffins having different melting points are used, the temperature range in which the heat storage property is exhibited can be expanded.

When a plurality of types of paraffin wax are used, the content of the main paraffin wax with respect to the total mass of the paraffin wax is preferably 80 to 100 mass%, more preferably 90 to 100 mass%, and still more preferably 95 to 100 mass%, from the viewpoint of the temperature range in which heat storage properties are exhibited and the heat storage amount. The "main paraffin" refers to a paraffin contained in the largest amount among a plurality of paraffins. The content of the main paraffin is preferably 50 mass% or more with respect to the total amount of the plurality of kinds of paraffins.

The content of paraffin is preferably 80 to 100 mass%, more preferably 90 to 100 mass%, and still more preferably 95 to 100 mass% with respect to the total mass of the heat storage material (preferably the latent heat storage material).

In the heat-accumulative composition, the heat-accumulative material may be present outside the microcapsule. That is, the heat storage composition may contain the heat storage material contained in the microcapsule and the heat storage material inside the heat storage composition and outside the microcapsule. In this case, it is preferable that the heat-accumulative material is contained in the microcapsules in an amount of 95 mass% or more of the total mass of the heat-accumulative material contained in the heat-accumulative composition. That is, the content (inclusion rate) of the heat-accumulative material contained in the microcapsule is preferably 95 mass% or more of the total mass of the heat-accumulative material contained in the heat-accumulative composition. The upper limit is not particularly limited, and may be 100 mass%.

The heat-accumulative material in the heat-accumulative composition is advantageous in that it can prevent the heat-accumulative material which becomes liquid at high temperature from leaking out of the heat-accumulative composition by containing the heat-accumulative material in the microcapsules in an amount of 95 mass% or more based on the total mass, can maintain the heat-accumulative amount of the heat-accumulative composition without contaminating peripheral members used in the heat-accumulative composition, and can delay combustion and ignition.

In the present invention, from the viewpoint of the heat-accumulative material's total mass, the content of the heat-accumulative material in the heat-accumulative material is preferably 65 mass% or more, more preferably 70 mass% or more, still more preferably 75 mass% or more, and particularly preferably 80 mass% or more. When the composition of the present invention is applied to a heat-accumulative composition containing 65 mass% or more of a heat-accumulative material, the flame retardancy and ignition resistance can be improved while maintaining a high heat absorption amount. The content of the heat-accumulative material can be adjusted by a method of reducing the wall thickness of the microcapsule, a method of increasing the content of the microcapsule, and a combination of such methods. The content of the heat-accumulative material in the heat-accumulative composition is preferably 99.9% by mass or less, more preferably 99% by mass or less, and still more preferably 98% by mass or less, based on the total mass of the heat-accumulative composition.

The measurement of the content of the heat storage material in the heat storage composition was performed by the following method.

First, the heat-accumulative material is taken out of the heat-accumulative composition and the kind of the heat-accumulative material is identified. In addition, when the heat storage material is composed of a plurality of kinds, the mixing ratio thereof is also identified. Examples of the identification method include NMR (Nuclear Magnetic Resonance) measurement and IR (infrared spectroscopy) measurement. Further, as a method of taking out the heat storage material from the heat storage composition, there is a method of immersing the heat storage composition in a solvent (for example, an organic solvent) to extract the heat storage material.

Next, the heat-accumulative material contained in the heat-accumulative composition identified by the above procedure was separately prepared, and the amount of heat absorption (J/g) of the heat-accumulative material alone was measured using a Differential Scanning Calorimeter (DSC). The obtained endothermic amount was taken as an endothermic amount A. When the heat storage material is composed of a plurality of types as described above, the heat storage material having the above-described mixture ratio is separately prepared, and the amount of heat absorption is measured.

Next, the endothermic amount of the heat-accumulative composition was measured in the same manner as described above. The obtained endothermic amount was taken as endothermic amount B.

Then, the ratio X (%) to the heat absorption A { (B/A) × 100} is calculated. This ratio X corresponds to the content of the heat storage material in the heat storage composition (the ratio of the content of the heat storage material to the total mass of the heat storage composition). For example, if the heat-accumulative composition meter is made of a heat-accumulative material, the amount of heat absorbed a and the amount of heat absorbed B are the same, and the ratio X (%) is 100%. In contrast, when the content of the heat storage material in the heat storage composition is a predetermined ratio, the amount of heat absorption becomes a value corresponding to the ratio. That is, the content of the heat storage material in the heat storage composition can be determined by comparing the heat absorption amount a and the heat absorption amount B.

Other ingredients-

Examples of other components that can be contained as the core material in the microcapsule include additives such as a solvent and a flame retardant.

The microcapsule may contain other components as the core material, but from the viewpoint of heat storage properties, the content of the heat storage material in the core material is preferably 80 to 100% by mass, and more preferably 100% by mass, based on the total mass of the core material.

The microcapsule may contain a solvent as an oil component in the core part within a range not significantly impairing the heat-accumulative effect.

Examples of the solvent include the heat-accumulative material having a melting point deviated from a temperature range in which the heat-accumulative composition is used (heat control range; e.g., operating temperature of heat-generating body). That is, the solvent is a heat storage material that does not change its phase in a liquid state in the heat control region and is classified into a heat storage material that causes a phase transition in the heat control region to generate an endothermic/exothermic reaction.

The content of the solvent in the inner package component is preferably less than 30% by mass, more preferably less than 10% by mass, and still more preferably 1% by mass or less, relative to the total mass of the inner package component. The lower limit is not particularly limited, and may be 0 mass%.

In addition, one kind of the solvent may be used alone, or two or more kinds may be used in combination.

In addition to the above components, for example, additives such as an ultraviolet absorber, a photosensitizer, an antioxidant, paraffin, and a deodorant may be contained in the core material of the microcapsule as necessary.

(wall part (capsule wall))

The microcapsules have a wall portion (capsule wall) comprising a core material.

By having a capsule wall, capsule particles can be formed and can comprise the above-mentioned core material forming the core.

Capsule wall forming materials

The material for forming the capsule wall of the microcapsule is not particularly limited as long as it is a polymer, and examples thereof include polyurethane, polyurea, polyurethaneurea, melamine resin, and acrylic resin. From the viewpoint of imparting excellent heat storage properties by thinning the capsule wall, polyurethane, polyurea, polyurethaneurea, or melamine resin is preferable, and polyurethane, polyurea, or polyurethaneurea is more preferable. Further, polyurethane, polyurea, or polyurethaneurea is more preferable from the viewpoint of preventing a phase change, a structural change, or the like of the heat storage material from being likely to occur at the interface between the wall material and the heat storage material.

Also, the microcapsules are preferably present as deformed particles.

When the microcapsules are deformed particles, they can be deformed without breaking, and the filling rate of the microcapsules can be increased. As a result, the amount of the heat-accumulative material in the heat-accumulative composition can be increased to realize more excellent heat-accumulative capacity. From this viewpoint, as a material forming the capsule wall, polyurethane, polyurea, or polyurethaneurea is preferable.

As for the deformation without rupture of the microcapsules, as long as the deformation is confirmed from the shape in the state where no external pressure is applied to the respective microcapsules, it can be considered as a deformed state regardless of the degree of the deformation amount. For example, the following properties are expressed: when the microcapsules are to be densely present in the sheet, even if the respective capsules are subjected to pressure by pressing the microcapsules against each other in the sheet, the capsule walls are not broken and the pressure applied to the capsules is relaxed by deformation, thereby maintaining the state in which the core material is contained in the microcapsules.

When the microcapsules are pressed against each other in the sheet, the deformation generated in the microcapsules includes, for example, deformation in which spherical surfaces contact each other to form a flat contact surface.

From the above viewpoint, the deformation ratio of the microcapsule is preferably 10% or more, and more preferably 30% or more. From the viewpoint of the physical strength and durability of the capsule, the upper limit of the deformation rate of the microcapsule may be 80% or less.

(content of microcapsule)

The content of the microcapsules in the heat-accumulative composition is usually 70% by mass or more based on the total mass of the heat-accumulative composition. Among them, 75% by mass or more is preferable. When the content of the microcapsules is 75% by mass or more, the amount of the heat-accumulative material present relative to the total mass of the heat-accumulative composition can be increased, and as a result, the heat-accumulative composition having excellent heat-accumulative capacity can be obtained.

From the viewpoint of heat-accumulative property, the content of the microcapsule in the heat-accumulative composition is preferably high. Specifically, the content of the microcapsule in the heat-accumulative composition is preferably 80% by mass or more, more preferably 85 to 99% by mass, and still more preferably 90 to 99% by mass.

The microcapsules may be used alone or in combination of two or more.

(method for producing microcapsule)

The microcapsules can be produced, for example, by the following method.

When the microcapsule wall is formed of polyurethane, polyurea, or polyurethaneurea, a method of applying an interfacial polymerization method including the following steps is exemplified as a method of producing microcapsules: a step (emulsification step) of dispersing an oil phase containing a heat-accumulative material and a capsule wall material in an aqueous phase containing an emulsifier to prepare an emulsion; and a step (encapsulation step) in which the capsule wall material is polymerized at the interface between the oil phase and the water phase to form a capsule wall, thereby forming microcapsules containing the heat-accumulative material.

Further, as the capsule wall material, for example, there can be mentioned a capsule wall material containing a polyisocyanate and at least one selected from the group consisting of a polyol and a polyamine. In addition, a part of the polyisocyanate may react with water in the reaction system to become a polyamine. Therefore, if the capsule wall material contains at least polyisocyanate, polyurea can be synthesized by converting a part of the material into polyamine and reacting the polyisocyanate with the polyamine.

When the capsule wall is formed of a melamine formaldehyde resin, microcapsules can be produced by applying a gel method including: a step (emulsification step) of dispersing an oil phase containing a heat-accumulative material in an aqueous phase containing an emulsifier to prepare an emulsion; and a step (an encapsulation step) of adding the capsule wall material to the aqueous phase to form a polymer layer on the surface of the emulsified liquid droplets, the polymer layer being formed from the capsule wall material, thereby forming microcapsules containing a heat storage material.

-an emulsification procedure-

In the emulsification step, when the capsule wall is formed of polyurethane, polyurea, or polyurethaneurea, an oil phase containing the heat storage material and the capsule wall material is dispersed in an aqueous phase containing an emulsifier to prepare an emulsion.

When the capsule wall is formed of a melamine-formaldehyde resin, an emulsion is prepared by dispersing an oil phase containing a heat-accumulative material in an aqueous phase containing an emulsifier.

Emulsion as fast as

The emulsion is formed by dispersing an oil phase containing the heat-accumulative material and the capsule wall material (if necessary) in an aqueous phase containing an emulsifier.

(1) Oil phase

The oil phase contains at least a heat-accumulative material, and may further contain components such as a capsule wall material, a solvent and/or additives as required.

Examples of the solvent include the heat-accumulative material having a melting point deviated from a temperature range in which the heat-accumulative composition is used (heat control range; e.g., operating temperature of heat-generating body).

(2) Aqueous phase

The aqueous phase contains at least an aqueous medium and an emulsifier.

Aqueous medium-

Examples of the aqueous medium include water and a mixed solvent of water and a water-soluble organic solvent, and water is preferred. The term "water-soluble" of the water-soluble organic solvent means that the amount of the target substance dissolved in 100 mass% water at 25 ℃ is 5 mass% or more.

The content of the aqueous medium is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and still more preferably 40 to 60% by mass, based on the total mass of the emulsion as a mixture of the oil phase and the water phase.

Emulsifiers-

The emulsifier comprises a dispersant, a surfactant, or a combination thereof.

Examples of the dispersant include a binder described later, and polyvinyl alcohol is preferable.

As the polyvinyl alcohol, commercially available products can be used, and examples thereof include KURARAY CO., KURAY POVAL series manufactured by LTD (e.g., KURAY POVAL PVA-217E, KURAY POVAL KL-318, etc.).

The polymerization degree of the polyvinyl alcohol is preferably 500 to 5000, more preferably 1000 to 3000, from the viewpoint of dispersibility of the microcapsule.

Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. The surfactants may be used alone or in combination of two or more.

From the viewpoint of enhancing the film strength, the emulsifier is preferably an emulsifier capable of bonding with the polyisocyanate. For example, when microcapsules are produced using a capsule wall material containing polyisocyanate, polyvinyl alcohol as an emulsifier can be bonded to the polyisocyanate. That is, the hydroxyl group in the polyvinyl alcohol can be bonded to the polyisocyanate.

The concentration of the emulsifier is preferably more than 0% by mass and 20% by mass or less, more preferably 0.005 to 10% by mass, even more preferably 0.01 to 10% by mass, and particularly preferably 1 to 5% by mass, based on the total mass of the emulsion which is a mixture of the oil phase and the water phase.

As described later, when a heat-accumulative composition is prepared using a dispersion in which microcapsules prepared using an emulsifier are dispersed, the emulsifier may remain in the heat-accumulative composition as a binder. As described later, in order to reduce the content of the binder in the heat-accumulative composition, the amount of the emulsifier used is preferably small within a range that does not impair the emulsifying properties.

The aqueous phase may contain other components such as an ultraviolet absorber, an antioxidant and a preservative as required.

When the heat-accumulative composition contains microcapsules, the flame retardant may be contained in either of the oil phase and the aqueous phase, and is preferably contained in the aqueous phase.

Disperse ^ E

Dispersion means that the oil phase is dispersed in the water phase as oil droplets (emulsification). The dispersion may be carried out using a known method for oil phase and aqueous phase dispersion, such as a homogenizer, a high pressure emulsifier (Menton Gorley), an ultrasonic disperser, a dissolver, a cady Mill (Keddy Mill), or other known dispersing means.

The mixing ratio of the oil phase to the water phase (oil phase mass/water phase mass) is preferably 0.1 to 1.5, more preferably 0.2 to 1.2, and still more preferably 0.4 to 1.0. When the mixing ratio is within the range of 0.1 to 1.5, the viscosity can be maintained at an appropriate level, and the emulsion is excellent in production suitability and stability.

Encapsulation procedure

In the encapsulation step, the capsule wall material is polymerized at the interface between the oil phase and the water phase to form a capsule wall, thereby forming microcapsules containing the heat storage material.

Polymerization ^

The polymerization is a step of polymerizing a capsule wall material contained in an oil phase in an emulsion at an interface with an aqueous phase, thereby forming a capsule wall. The polymerization is preferably carried out under heating. The reaction temperature in the polymerization is preferably 40 to 100 ℃, and more preferably 50 to 80 ℃. The reaction time for the polymerization is preferably about 0.5 to 10 hours, more preferably about 1 to 5 hours. The higher the polymerization temperature, the shorter the polymerization time becomes, but when inclusion and/or capsule wall materials which are likely to decompose at high temperatures are used, it is preferable to select a polymerization initiator which acts at a low temperature to carry out the polymerization at a relatively low temperature.

In the polymerization step, in order to prevent the microcapsules from agglomerating, it is preferable to further add an aqueous solution (e.g., water, an aqueous acetic acid solution, or the like) to reduce the probability of collision between the microcapsules, and to sufficiently stir the microcapsules. The coagulation-preventing dispersant may be added again in the polymerization step. Further, if necessary, a charge control agent such as nigrosine or any other auxiliary agent may be added to the emulsion. These adjuvants can be added to the emulsion at the time of capsule wall formation or at any time.

The heat-accumulative material contained in the heat-accumulative composition may be present in a form not contained in the microcapsule. The composition of the heat-accumulative composition in the case where the heat-accumulative material contained in the heat-accumulative composition is not contained in the microcapsule is preferably the same as that in the case where the microcapsule is contained, except that the heat-accumulative composition corresponding to the above-mentioned core material is contained instead of the microcapsule.

The composition corresponding to the core material in this case may be the same as the matter described for the core material, including the preferable composition and mode thereof.

< flame retardant >

The flame retardant contained in the heat-accumulative composition is not particularly limited as long as it has a composition such that the gas generation temperature Tr, as measured by the measuring method 1, satisfies the condition a.

The flame retardant is not particularly limited if the gas generation temperature Tr is within an appropriate range, but when the heat storage composition is used in an electronic device, a non-metallic material is preferable from the viewpoint of preventing contamination and suppressing electrical conductivity. Among these, from the viewpoint of environmental and corrosive properties, a material containing no halogen is preferable, and a phosphorus-containing material (i.e., a flame retardant containing a phosphorus atom) is more preferable.

Also, it is preferred that the flame retardant is not encapsulated. By disposing the non-encapsulated flame retardant outside the capsule containing the heat-accumulative material, the flame retardant can be burned faster than the combustion of the specific composition, and as a result, the flame retardant and the ignition resistance can be made more excellent.

The heat-accumulative composition further preferably contains at least one selected from the group consisting of diammonium hydrogen phosphate, ammonium dihydrogen phosphate and trimethyl phosphate as a flame retardant, and particularly preferably contains diammonium hydrogen phosphate or ammonium dihydrogen phosphate from the viewpoint of further excellent storage stability of the heat-accumulative composition.

As the phosphorus-containing material, commercially available ones can be used, and examples thereof include Taien series (e.g., Taien N) manufactured by Taihei Chemical Industrial Co.' Ltd.

The heat-accumulative composition may contain a flame retardant other than the above-mentioned preferred flame retardants (hereinafter, also referred to as "other flame retardant") within a range satisfying the condition A.

The other flame retardant is not particularly limited, and known flame retardants can be used. For example, a flame retardant described in "application technology of flame retardant/flame retardant material" (published by CMC Publishing co., ltd.) or the like can be used, and a halogen-based flame retardant, a flame retardant containing a phosphorus atom (phosphorus-based flame retardant), or an inorganic flame retardant is preferably used. When it is desired to suppress the incorporation of halogen in electronic applications, phosphorus flame retardants and inorganic flame retardants are more preferably used.

Examples of the phosphorus-based flame retardant to be contained in the other flame retardant include phosphate-based materials such as triphenyl phosphate, tricresyl phosphate, trixylyl phosphate, cresyl phenyl phosphate, and 2-ethylhexyl diphenyl phosphate, aromatic phosphate esters other than the phosphate-based materials, aromatic condensed phosphate esters, benzene ring salts, metal phosphates, and red phosphorus.

In the case where the heat-accumulative composition contains microcapsules containing a heat-accumulative material, the flame retardant may be present in any of the interior, wall and exterior of the microcapsules, but the flame retardant is preferably present in the exterior of the microcapsules from the viewpoint of not changing the properties such as heat-accumulative capacity of the microcapsules and the properties such as strength of the capsule wall.

The flame retardant may be used alone in 1 kind, or two or more kinds may be used in combination.

The content of the flame retardant in the heat-accumulative composition is preferably 0.01 to 20% by mass, more preferably 0.01 to 15% by mass, and still more preferably 0.05 to 5% by mass, based on the total mass of the heat-accumulative composition, from the viewpoint of heat-accumulative capacity and flame retardancy.

From the viewpoint of more excellent flame retardancy, the content of the flame retardant is preferably 0.01 mass% or more, and more preferably 0.1 mass% or more, relative to the content of the heat-accumulative material. The upper limit is not particularly limited, but a large content of the heat storage material reduces the content of the heat storage material in the heat storage member and reduces the heat storage amount, and therefore the content is preferably 5 mass% or less, and more preferably 1 mass% or less.

The heat-accumulative composition preferably further contains a flame-retardant auxiliary together with the flame retardant. Examples of the flame retardant aid include pentaerythritol, phosphorous acid, and 22 oxo-4 zinc 12 boron 7 hydrate.

< adhesive agent >

The heat-accumulative composition preferably contains at least one binder outside the microcapsules in addition to the microcapsules. The heat-accumulative composition can be provided with durability by containing a binder.

In addition, as described above, an emulsifier such as polyvinyl alcohol may be used in the production of the microcapsule. Therefore, when a heat-accumulative composition is prepared using a microcapsule-containing composition formed using an emulsifier, a binder derived from the emulsifier may be contained in the heat-accumulative composition.

The binder is not particularly limited as long as it is a polymer capable of forming a film, and examples thereof include a water-soluble polymer and an oil-soluble polymer.

The term "water-soluble" of the water-soluble polymer means that the amount of the target substance dissolved in 100 mass% water at 25 ℃ is 5 mass% or more. The water-soluble polymer is preferably a polymer having a dissolution amount of 10% by mass or more.

The "oil-soluble polymer" described later means a polymer other than the "water-soluble polymer".

Examples of the water-soluble polymer include polyvinyl alcohol and modified products thereof, polyacrylic acid amide and derivatives thereof, styrene-acrylic acid copolymers, sodium polystyrene sulfonate, ethylene-vinyl acetate copolymers, styrene-maleic anhydride copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, polyvinyl pyrrolidone, ethylene-acrylic acid copolymers, vinyl acetate-acrylic acid copolymers, carboxymethyl cellulose, methyl cellulose, casein, gelatin, starch derivatives, gum arabic, and sodium alginate, and polyvinyl alcohol is preferable.

Examples of the oil-soluble polymer include a polymer having a heat-accumulative property described in International publication No. 2018/207387 and Japanese patent application laid-open No. 2007-31610, preferably a polymer having a long-chain alkyl group (more preferably a long-chain alkyl group having 12 to 30 carbon atoms), and more preferably an acrylic resin having a long-chain alkyl group (more preferably a long-chain alkyl group having 12 to 30 carbon atoms).

In addition to the above, examples of the oil-soluble polymer include modified polyvinyl alcohol, derivatives of polyacrylamides, ethylene-vinyl acetate copolymers, styrene-maleic anhydride copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, ethylene-acrylic acid copolymers, vinyl acetate-acrylic acid copolymers, and styrene-acrylic acid copolymers.

In the binder, the water-soluble polymer is preferable, the polyol is more preferable, and the polyvinyl alcohol is further preferable, from the viewpoint of making the content of the microcapsule in the heat-accumulative composition to be 70 mass% or more (preferably 75 mass% or more). By using the water-soluble polymer, a composition suitable for forming a heat-accumulative composition in a sheet form can be prepared while maintaining dispersibility in the preparation of an oil/water (O/W (oil in Water)) type microcapsule liquid in which a core material is an oil-soluble material such as paraffin. This makes it easy to adjust the content of the microcapsules in the heat-accumulative composition to 70 mass% or more.

As the polyvinyl alcohol, commercially available products can be used, and examples thereof include KURARAY CO., KURAY POVAL series manufactured by LTD (e.g., KURAY POVAL PVA-217E, KURAY POVAL KL-318, etc.).

When the binder is polyvinyl alcohol, the degree of polymerization of polyvinyl alcohol is preferably 500 to 5000, and more preferably 1000 to 3000, from the viewpoint of dispersibility of the microcapsule and film strength.

The content of the binder in the heat-accumulative composition is preferably 0.1 to 20% by mass, more preferably 1 to 11% by mass, from the viewpoint of easily adjusting the content of the microcapsules in the heat-accumulative composition to 70% by mass or more while maintaining the film strength of the heat-accumulative composition.

The smaller the content of the binder, the more microcapsules are contained in the total mass, and therefore, the less the binder content is preferred. Also, if the content of the binder is not excessively low, the binder protects the microcapsules and easily maintains the ability to form a layer containing the microcapsules, and thus microcapsules having physical strength are easily obtained.

The content of the binder in the heat-accumulative composition is not particularly limited, but is preferably 15% by mass or less, more preferably 11% by mass or less, from the viewpoint of more excellent heat-accumulative property of the heat-accumulative composition. The lower limit is not particularly limited, but is preferably 0.1 mass% or more.

Molecular weight &

The number average molecular weight (Mn) of the binder is preferably 20,000 to 300,000, more preferably 20,000 to 150,000, from the viewpoint of film strength.

The number average molecular weight (Mn) of the binder is a value measured by Gel Permeation Chromatography (GPC).

In the measurement by Gel Permeation Chromatography (GPC), HLC (registered trademark) -8020GPC (TOSOH CORPORATION) was used as a measuring device, 3 TSKgel (registered trademark) Super Multipore HZ-H (4.6mm ID. times.15 cm, TOSOH CORPORATION) was used as a column, and THF (tetrahydrofuran) was used as an eluent. As the measurement conditions, the sample concentration was set to 0.45 mass%, the flow rate was set to 0.35ml/min, the sample injection amount was set to 10 μ l, and the measurement temperature was set to 40 ℃, and measurement was performed using an RI (differential refractive index) detector.

Calibration curves were based on "standard TSK standard, polystyrene" from TOSOH CORPORATION: 8 samples of "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000" and "n-propylbenzene" were prepared.

< solvent >

The thermal storage composition may contain a solvent. In the case where the heat-accumulative composition contains microcapsules, the heat-accumulative composition preferably contains a solvent as a dispersion medium. By incorporating a solvent as a dispersion medium of the microcapsules in the heat-accumulative composition, the heat-accumulative composition can be easily blended with other materials when used in various applications.

The solvent can be appropriately selected depending on the use of the heat-accumulative composition. The solvent contained in the heat-accumulative composition containing microcapsules is preferably a liquid component which does not affect the wall material of the microcapsules. Examples of the liquid component include an aqueous solvent, a viscosity modifier, and a stabilizer. Examples of the stabilizer include emulsifiers that can be used in the aqueous phase.

Examples of the aqueous solvent include water such as ion-exchanged water and alcohol.

The solvent contained in the heat-accumulative composition may be used alone or in combination of two or more.

When the heat-accumulative composition contains a solvent, the content of the solvent may be appropriately selected depending on the application, and is preferably 0.0001 to 0.1% by mass.

The heat-accumulative composition may contain a specific solvent having a boiling point of 100 ℃ or lower.

Examples of the specific solvent include water and aqueous organic solvents such as alcohols, ketones, and esters having 1 to 7 carbon atoms.

The specific solvent contained in the heat-accumulative composition may be used alone or in combination of two or more.

When the heat-accumulative composition contains a specific solvent, the content of the specific solvent is preferably 1% by mass or less based on the total mass of the heat-accumulative composition. Among these, the heat-accumulative composition preferably contains substantially no specific solvent. The phrase "substantially not containing a specific solvent" means that the content of the specific solvent is 0.5% by mass or less with respect to the total mass of the heat-accumulative composition. The lower limit is not particularly limited, and may be 0 mass% (detection limit or less).

< other ingredients >

The heat-accumulative composition may contain other components such as a heat-conductive material, an ultraviolet absorber, an antioxidant and a preservative as required outside the microcapsules.

The content of other components that may be present outside the microcapsules is preferably 10% by mass or less, more preferably 5% by mass or less, relative to the total mass of the heat-accumulative composition. From the viewpoint of increasing the gas generation temperature Ta of the specific member to improve the stability of the heat-accumulative composition during use, the heat-accumulative composition preferably contains substantially no other component. "substantially not contained" means that the content thereof is 1 mass% or less with respect to the total mass of the heat-accumulative composition. The total amount of the microcapsules and the binder is preferably 80% by mass or more, more preferably 90 to 100% by mass, and still more preferably 98 to 100% by mass, based on the total mass of the heat-accumulative composition.

-thermally conductive material

The heat-accumulative composition preferably further contains a heat-conductive material outside the microcapsule. By containing the heat conductive material, the heat storage composition after heat storage is excellent in heat dissipation and can maintain the cooling efficiency, cooling rate, and temperature of the heat generating element satisfactorily.

"thermal conductivity" of a thermally conductive material means a thermal conductivity of 10Wm^-1K^-1The above materials. Among them, the thermal conductivity of the thermally conductive material is preferably 50Wm from the viewpoint of improving the heat dissipation property of the heat storage composition^-1K^-1The above.

Thermal conductivity (unit: Wm)^-1K^-1) Is a value measured by a flash method at a temperature of 25 ℃ by a method in accordance with Japanese Industrial Standard (JIS) R1611.

Examples of the heat conductive material include carbon (artificial graphite, carbon black, etc.; 100 to 250), carbon nanotubes (3000 to 5500), metals (e.g., silver: 420, copper: 398, gold: 320, aluminum: 236, iron: 84, platinum: 70, stainless steel: 16.7 to 20.9, and nickel: 90.9), and silicon (Si; 168).

The numerical values in parentheses above indicate the thermal conductivity (unit: Wm) of each material^-1K^-1)。

The content of the thermally conductive material in the heat-accumulative composition is preferably 2% by mass or more based on the total mass of the heat-accumulative composition. From the viewpoint of the balance between heat storage and heat dissipation of the heat storage composition, the content of the heat conductive material is preferably 10% by mass or less, and more preferably 5% by mass or less.

[ Properties of Heat-accumulative composition ]

(latent capacity)

The latent heat capacity of the heat-accumulative composition is preferably 110J/ml or more, more preferably 135J/ml or more, and still more preferably 145J/ml or more, from the viewpoint of high heat-accumulative capacity and suitability for temperature control of a heat-generating body generating heat. The upper limit is not particularly limited, but is usually 400J/ml or less.

The latent heat capacity is a value calculated from the measurement result of a Differential Scanning Calorimeter (DSC) and the thickness of the heat storage composition.

In addition, from the viewpoint of achieving a high stored heat amount in a limited space, a stored heat amount in units of "J/ml (stored heat amount per unit volume)" is suitable, but the weight of electronic equipment is also important in applications such as electronic equipment. Therefore, from the viewpoint of exhibiting high heat storage performance within a limited mass, a heat storage amount in units of "J/g (heat storage amount per unit mass)" may be appropriate. In this case, the latent heat capacity is preferably 140J/g or more, more preferably 150J/g or more, further preferably 160J/g or more, and particularly preferably 190J/g or more. The upper limit is not particularly limited, but is usually 450J/g or less.

(porosity)

The proportion of the volume of the microcapsule in the volume of the heat-accumulative composition is preferably 40% by volume or more, more preferably 60% by volume or more, and still more preferably 80% by volume or more. The upper limit is not particularly limited, and may be 100 vol%.

If the heat-accumulative composition contains voids, the volume of the heat-accumulative composition increases even if the heat-accumulative material or microcapsule is contained in the same amount in the heat-accumulative composition. Therefore, in the case where the space occupied by the heat-accumulative composition is to be reduced, the heat-accumulative composition preferably has no pores. From this viewpoint, the proportion of the volume of the pores in the heat-accumulative composition (porosity) is preferably 50% by volume or less, more preferably 40% by volume or less, still more preferably 20% by volume or less, particularly preferably 15% by volume or less, and most preferably 10% by volume or less. The lower limit is not particularly limited, and may be 0 vol%.

The shape of the heat-accumulative composition is not particularly limited, and may be an amorphous form having fluidity such as a liquid form or a slurry form, or may have a shape such as a sheet form or a granular form.

When the heat-accumulative composition is in the form of a sheet, the heat-accumulative composition may have other layers such as a protective layer, a base material and an adhesion layer in addition to the layer containing the heat-accumulative material (preferably, microcapsules containing the heat-accumulative material). In the case where the sheet-shaped heat storage composition has other layers, the flame retardant may be contained in the other layers.

The other layers that the sheet-shaped heat storage composition may have, such as a protective layer, a base material, and an adhesion layer, will be described in detail in the heat storage member described later.

[ method for producing Heat-accumulative composition ]

The method for producing the heat-accumulative composition is not particularly limited. For example, a liquid heat-accumulative composition (dispersion of microcapsules) can be prepared by mixing any of the components including microcapsules (or a composition corresponding to the core material), a flame retardant, and a binder used as necessary. The sheet-like heat-accumulative composition can be prepared by applying the dispersion of microcapsules to a base material and drying the applied dispersion.

Examples of the coating method include die coating, air knife coating, roll coating, knife coating, gravure coating, and curtain coating, and among them, knife coating, gravure coating, and curtain coating are preferable. Further, a method of casting a dispersion liquid containing microcapsules containing a heat-accumulative material and a binder to form a layer may be mentioned.

In the case of an aqueous solvent, the drying is preferably carried out at 60 to 130 ℃.

In the drying step, the layer containing the microcapsules (for example, the heat-accumulative composition comprising a single layer) may be flattened by using a roller. Further, an operation of increasing the filling rate of the microcapsules in the film by applying pressure to the layer containing the microcapsules (for example, the heat-accumulative composition composed of a single layer) using an apparatus such as a roll or a calender may be performed.

In order to reduce the porosity in the heat-accumulative composition, it is preferable to employ at least one method selected from the group consisting of a step of using microcapsules which are easily deformable, a step of applying the heat-accumulative material contained in the microcapsules at a temperature of the melting point or higher, a step of slowly drying when forming a layer containing the microcapsules, and a step of applying the heat-accumulative material several times instead of forming a coating layer of a thick film at one time.

As one of preferred embodiments of the method for producing the heat-accumulative composition, there can be mentioned a method comprising the steps of: the method for producing a heat-accumulative material comprises a step A of mixing a heat-accumulative material, a polyisocyanate, at least one active hydrogen-containing compound selected from the group consisting of a polyol and a polyamine, and an emulsifier to prepare a dispersion containing microcapsules containing at least a part of the heat-accumulative material, and a step B of preparing a heat-accumulative composition using the dispersion without substantially adding a binder to the dispersion.

According to the above method, since the heat-accumulative composition is prepared without using a binder, the content of the microcapsules in the heat-accumulative composition can be increased, and as a result, the content of the heat-accumulative material in the heat-accumulative composition can be increased.

In addition, the content (inclusion rate) of the heat-accumulative material contained in the microcapsules in the total amount of the heat-accumulative material used in the step A is preferably 95 mass% or more. The upper limit is not particularly limited, and may be 100 mass%.

The description of the material (at least one active hydrogen-containing compound selected from the group consisting of a heat-accumulative material, polyisocyanate, polyol and polyamine, and an emulsifier) used in the step a is as described above.

The procedure for producing the microcapsules in step a includes the above-mentioned method. As a specific sequence of the step a, the following steps are preferably performed: the method for producing a microcapsule comprises a step (emulsification step) of dispersing an oil phase containing a heat-accumulative material and a capsule wall material (polyisocyanate, active hydrogen-containing compound) in an emulsifier-containing aqueous phase (more preferably, an emulsifier-and flame retardant-containing aqueous phase) to prepare an emulsion, and a step (encapsulation step) of polymerizing the capsule wall material at the interface between the oil phase and the aqueous phase to form a capsule wall, thereby forming a dispersion containing microcapsules containing a heat-accumulative material.

In the sequence of step B, a binder is not substantially added to the dispersion containing the microcapsules prepared as described above. That is, the dispersion obtained in step a is used for the preparation of the heat-accumulative composition substantially without adding a binder. Here, "substantially no binder is added" means that the amount of the binder added is 1 mass% or less based on the total mass of the microcapsules in the dispersion. The amount of the binder added is preferably 0.1% by mass or less, and more preferably 0% by mass, based on the total mass of the microcapsules in the dispersion.

In step B, as a procedure for producing a heat-accumulative composition using the dispersion, there may be mentioned a procedure for producing a sheet-like heat-accumulative composition by coating a substrate with the dispersion and drying the coating film, as described above.

Preferred embodiments of the order of step B and the production conditions including the method of applying the dispersion liquid and the method of drying the coating film are as described above.

In the case where the sheet-shaped heat-accumulative composition is prepared by the method comprising the above-mentioned steps A and B, the step of adding the flame retardant may be any of the steps A, B and others, but the dispersion prepared in the step A preferably contains the flame retardant, and the aqueous phase containing the emulsifier used in the step A more preferably contains the flame retardant.

[ Heat accumulating sheet ]

As an example of the sheet-shaped heat storage composition, a sheet (hereinafter, also referred to as "heat storage sheet") including a layer composed of a heat storage material (preferably, microcapsules containing a heat storage material) and a flame retardant is described.

The heat-accumulative material and flame retardant contained in the heat-accumulative sheet, and the composition of the heat-accumulative sheet, including preferred embodiments thereof, may be the same as those described for the heat-accumulative composition.

The components that the heat-accumulative sheet may contain, including preferred embodiments thereof, such as a binder, a heat-conductive material, an ultraviolet absorber, an antioxidant and a preservative, may be the same as those described for the heat-accumulative composition.

< Properties of Heat storage sheet >

The thickness of the heat storage sheet is preferably 1 to 1000 μm, and more preferably 1 to 500 μm. The thickness of the heat storage sheet may be adjusted by the coating amount or film formation amount of the heat storage composition, or may be adjusted by laminating a plurality of heat storage sheets. The thickness of the heat storage sheet was set to the following average value: the cut surface of the heat storage sheet cut in the thickness direction was observed with a Scanning Electron Microscope (SEM), and the thickness of any 5 points was measured, and the average value of the thickness of 5 points was averaged.

The latent heat capacity and porosity of the heat storage sheet, including the preferred embodiments thereof, may be the same as those described for the heat storage composition.

The method for producing the heat storage sheet is not particularly limited, and may be the same as the matters described for the sheet-shaped heat storage composition, including preferred embodiments thereof.

[ Heat-storage Member ]

The heat storage member of the present invention contains a heat storage material and a flame retardant, and satisfies the following condition C: the gas generation temperature Tr of the flame retardant obtained by the measurement method C1 is lower than the gas generation temperature Tc of the specific member obtained by the measurement method C2.

Here, the "specific member" refers to a member obtained by removing the flame retardant and the specific solvent from the heat storage member.

[ Condition C ]

< measurement method C1>

The measurement method C1 for obtaining the gas generation temperature Tr of the flame retardant in the heat storage sheet is as follows. In addition, the description of measurement method a1 can be applied to the measurement method C1 in detail and in a preferred embodiment thereof, similarly to the above-mentioned measurement method a1, except that a heat-accumulative material is applied instead of the heat-accumulative composition.

First, the type and content of the flame retardant contained in the heat storage member were identified. Then, TG-DTA was used to measure the weight change caused by heating of the flame retardant. From the obtained measurement results, a relational expression between the temperature T (. degree. C.) represented by the following expression (C1) and the weight loss rate Δ ma (T) of the flame retardant was derived.

Δma(T)＝(ma₀-ma(T))/(ma₀) (C1)

In the formula (C1), ma (T) represents the weight of the flame retardant at a temperature T (. degree. C.), and ma₀Represents the weight of the flame retardant before heating.

Next, the temperature at which the weight loss rate Δ ma (t) of the flame retardant reaches 2 mass% was calculated using formula (C1), and the gas generation temperature Tr (C) of the flame retardant was obtained.

< measurement method C2>

The measurement method C2 for obtaining the gas generation temperature Tc of the specific member is as follows. In addition, as for the detailed embodiment and preferred embodiment of measurement method a2, the description of measurement method a2 can be applied to measurement method C2, except that a heat-accumulative material is applied instead of the heat-accumulative material and a specific material is applied instead of the specific material.

First, the change in weight of the heat storage member due to heating was measured using TG-DTA.

From the obtained measurement results, a relational expression between the temperature T (C) represented by the following expression (C2) and the weight loss rate Δ m3(T) of the heat storage member was derived.

Δm3(T)＝(m3₀-m3(T))/(m3₀) (C2)

In the formula (C2), m3(T) represents the weight of the heat storage member at a temperature T (. degree. C.), and m3₀The weight of the heat storage member before heating is shown.

Then, the type and content of the specific solvent contained in the heat storage member were identified. As a result of the measurement, in the case where the heat storage member contains a specific solvent, with respect to the specific solvent identified, TG-DTA was used to measure the weight change caused by heating.

From the obtained measurement results, a relational expression between the temperature T (C) represented by the following expression (C3) and the weight loss rate Δ mb (T) of the specific solvent was derived.

Δmb(T)＝(mb₀-mb(T))/(mb₀) (C3)

In the formula (C3), mb (T) represents the weight of a specific solvent at a temperature T (. degree. C.), mb₀Represents the weight of the specific solvent before heating.

Next, a relational expression between the temperature T (C) represented by the following expression (C4) and the weight loss rate Δ mz (T) of the specific member obtained by removing the flame retardant and the specific solvent from the heat storage member is derived.

Δmz(T)＝(100*Δm3(T)-a*Δma(T)-b*Δmb(T))/(100-a-b)(C4)

In formula (C4), a represents the ratio (% by mass) of the content of the flame retardant (the total content thereof in the case where two or more flame retardants are present) to the total mass of the heat storage member. b represents a ratio (% by mass) of the content of the specific solvent (in the case where two or more specific solvents are present, the total content thereof) to the total mass of the heat storage member. Δ ma (t) represents the weight loss rate of the flame retardant determined in measurement method C1.

The temperature at which the weight loss rate Δ mz (t) of the specific member reached 2 mass% was determined using the formula (C4), and this was taken as the gas generation temperature Tc (C) of the specific member.

Comparing the gas generation temperature Tr of the flame retardant obtained by the above-mentioned measurement method C1 with the gas generation temperature Tc of the specific member obtained by the above-mentioned measurement method C2, the heat storage sheet satisfies the condition C in the case where the gas generation temperature Tr of the flame retardant is lower than the gas generation temperature Tc of the specific member (Tc-Tr > 0).

The reason why the flame retardancy and the ignition resistance of the heat storage member satisfying the condition C are improved is the same as the reason why the flame retardancy and the ignition resistance of the heat storage composition satisfying the condition a are improved.

The gas generation temperature Tr of the flame retardant in the heat storage member, the gas generation temperature Tb of the specific member, and the content of the low-molecular-weight compound in the heat storage member, including preferred embodiments thereof, are the same as those described for the heat storage composition.

The structure of the heat storage member will be described below for each layer.

[ Heat storage layer ]

The heat storage material contained in the heat storage layer of the heat storage member and the flame retardant when the heat storage layer contains a flame retardant may be the same as those described for the heat storage composition, including preferred embodiments thereof.

The components that the heat-accumulative layer may contain, including preferred embodiments thereof, such as a binder, a heat-conductive material, an ultraviolet absorber, an antioxidant and an antiseptic, may be the same as those described for the heat-accumulative composition.

The physical properties of the heat storage layer and the method of producing the heat storage layer, including preferred embodiments thereof, may be the same as those described for the heat storage sheet.

From the viewpoint of the heat storage amount, the thickness of the heat storage layer in the heat storage member is preferably 50% or more, more preferably 70% or more, further preferably 80% or more, and particularly preferably 90% or more, with respect to the entire thickness of the heat storage member. The upper limit of the thickness of the heat storage layer in the heat storage member is preferably 99.9% or less, and more preferably 99% or less.

[ protective layer ]

The thermal storage member may have a protective layer. The protective layer is a layer that is disposed on the heat storage layer and has a function of protecting the heat storage layer. The protective layer can prevent scratches and bending during the process of manufacturing the heat storage member, and can provide workability. When the heat storage member has a base material, the protective layer is often disposed on the surface of the heat storage layer opposite to the base material.

The protective layer is preferably disposed on the outermost layer of the heat storage member. In the heat storage member, the phrase "the protective layer is disposed on the outermost layer" means that the protective layer is disposed on either one of both ends of the stacked body constituting the heat storage member in the stacking direction. Further, another layer may be further provided on the surface of the protective layer opposite to the surface facing the heat storage layer.

The protective layer may be disposed in contact with the heat storage layer, or may be disposed on the heat storage layer via another layer. It is preferable to fabricate the heat storage member in which the heat storage layer and the protective layer are in contact with each other by disposing the protective layer in contact with at least one surface of the heat storage layer.

Examples of a mode in which the heat storage member has a protective layer include a mode in which at least one of the heat storage layer and the protective layer contains a flame retardant, and more specifically, examples thereof include: a mode in which the heat storage layer contains a flame retardant and the protective layer does not contain a flame retardant; a mode in which the protective layer contains a flame retardant and the heat storage layer does not contain a flame retardant; and a mode in which both the heat storage layer and the protective layer contain a flame retardant.

The protective layer may contain a flame retardant, and from the viewpoint of further improving the heat storage property of the heat storage member, the protective layer preferably contains a flame retardant, and more preferably only the protective layer contains a flame retardant. And H, an embodiment in which both the heat storage layer and the protective layer contain a flame retardant is also preferable. In this case, the amount of the flame retardant contained in the protective layer is preferably larger than the amount of the flame retardant contained in the heat storage layer, and more preferably, the amount of the flame retardant contained in the heat storage layer is half or less of the amount of the flame retardant contained in the protective layer. By containing a larger amount of the flame retardant in the protective layer, flame retardancy can be improved while maintaining a high heat absorption amount. The mode of the flame retardant contained in the protective layer includes the preferable mode thereof, as described above.

The content of the flame retardant in the protective layer is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, further preferably 1% by mass or more, and particularly preferably 5% by mass or more, relative to the total mass of the protective layer, from the viewpoint of more excellent flame retardancy. The upper limit is not particularly limited, but from the viewpoint of further improving the heat storage amount of the heat storage member, the upper limit is preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, and particularly preferably 10% by mass or less.

The protective layer may contain inorganic particles such as silica as a flame retardant. The amount and kind of the inorganic particles can be adjusted according to the surface shape and/or the film quality. The size of the inorganic particles is preferably 0.01 to 1 μm, more preferably 0.05 to 0.2 μm, and still more preferably 0.1 to 0.1. mu.m. The content of the inorganic particles is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, based on the total mass of the protective layer.

Also, the protective layer preferably contains a flame retardant aid together with the flame retardant. Examples of the flame retardant aid include pentaerythritol, phosphorous acid, and 22 oxo-4 zinc 12 boron 7 hydrate.

The protective layer preferably has a crosslinked structure from the viewpoint of further improving the flame retardancy and ignition resistance of the heat storage member. In the present specification, the "crosslinked structure" refers to a network structure formed by crosslinking.

The reason why the flame retardancy and the ignition resistance of the heat storage member are further improved by the crosslinked structure of the protective layer is not clear, but it is presumed that the combustible gas generated by the decomposition of the heat storage material contained in the heat storage layer can be suppressed from leaking to the outside.

The presence or absence of a crosslinked structure in the protective layer of the heat storage member can be evaluated by the following method.

First, the heat storage member was cut in the stacking direction, and a sample having a 2cm square size was prepared. The obtained sample was immersed in 50ml of water, stirred with a stirrer for 10 minutes, and then taken out. The water solubility of the protective layer was evaluated by visually checking whether or not the protective layer remained on the surface of the sample taken out.

Next, the heat storage member was cut in the stacking direction, and a sample having a 2cm square size was prepared. The obtained sample was immersed in 50ml of N, N-Dimethylformamide (DMF), stirred with a stirrer for 10 minutes, and then taken out. The solvent solubility of the protective layer was evaluated by visually checking whether or not the protective layer remained on the surface of the sample taken out.

As a result of the above test, when the protective layer was left almost without dissolving in either water or DMF, the protective layer of the heat storage member was evaluated to have a crosslinked structure.

The material constituting the protective layer is not particularly limited as long as it can form a crosslinked structure, and is preferably a resin, and more preferably a resin selected from the group consisting of a resin containing a fluorine atom (hereinafter, also referred to as "fluororesin") and a silicone resin, from the viewpoint of further improving water resistance and flame retardancy.

The method for forming the crosslinked structure in the protective layer is not particularly limited, and a resin having a crosslinked structure formed by a known method can be used as a material constituting the protective layer.

For example, when a fluororesin is used, a crosslinked structure can be formed in the fluororesin by using a fluororesin having a structure containing a reactive group such as a hydroxyl group and an amide group, mixing a crosslinking agent having a substituent that reacts with the fluororesin, and reacting and crosslinking the mixture with the fluororesin.

In the case of a silicone resin, a silicone resin having a crosslinked structure can be produced by hydrolytic condensation using a compound having 3 or more hydrolyzable groups as the compound represented by formula (1) described below.

As the fluororesin, known one can be cited. Examples of the fluororesin include polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, and polytetrafluoroethylene.

The fluororesin may be a homopolymer obtained by polymerizing a fluorine-containing monomer alone, or a copolymer obtained by copolymerizing two or more fluorine-containing monomers. And, a copolymer of such a fluorine-containing monomer with a monomer other than the fluorine-containing monomer may be used.

Examples of the copolymer include a copolymer of tetrafluoroethylene and tetrafluoropropene, a copolymer of tetrafluoroethylene and vinylidene fluoride, a copolymer of tetrafluoroethylene and ethylene, a copolymer of tetrafluoroethylene and propylene, a copolymer of tetrafluoroethylene and vinyl ether, a copolymer of tetrafluoroethylene and perfluorovinyl ether, a copolymer of chlorotrifluoroethylene and vinyl ether, and a copolymer of chlorotrifluoroethylene and perfluorovinyl ether.

Examples of the fluororesin include Obbligato (registered trademark) SW0011F (AGC COAT-TECH co., ltd.); SIFCCLEAR-F101 and F102 (manufactured by JSR Corporation); and KYNAR AQUATEC (registered trademark) ARC and FMA-12 (both manufactured by Arkema corporation).

The silicone resin is a polymer having a repeating unit containing a siloxane skeleton, and is preferably a hydrolysis condensate of a compound represented by the following formula (1).

Si(X)_n(R)_4-nFormula (1)

X represents a hydrolyzable group. Examples of the hydrolyzable group include an alkoxy group, a halogen group, an acetoxy group, and an isocyanate group.

R represents a non-hydrolyzable group. Examples of the non-hydrolyzable group include an alkyl group (e.g., methyl, ethyl, and propyl), an aryl group (e.g., phenyl, tolyl, and mesityl), an alkenyl group (e.g., vinyl, and allyl), a haloalkyl group (e.g., γ -chloropropyl), an aminoalkyl group (e.g., γ -aminopropyl, and γ - (2-aminoethyl) aminopropyl), an epoxyalkyl group (e.g., γ -glycidoxypropyl, and β - (3, 4-epoxycyclohexyl) ethyl), a γ -mercaptoalkyl group, (meth) acryloyloxyalkyl group (γ -methacryloyloxypropyl), and a hydroxyalkyl group (e.g., γ -hydroxypropyl).

n represents an integer of 1 to 4, preferably 3 or 4.

The hydrolytic condensate is a compound obtained by hydrolyzing a hydrolyzable group in the compound represented by formula (1) and condensing the obtained hydrolysate. The hydrolytic condensate may be a condensate in which all of the hydrolyzable groups are hydrolyzed and all of the hydrolyzates are condensed (complete hydrolytic condensate), or a condensate in which a part of the hydrolyzable groups are hydrolyzed and a part of the hydrolyzates are condensed (partial hydrolytic condensate). That is, the above-mentioned hydrolytic condensate may be a complete hydrolytic condensate, a partial hydrolytic condensate or a mixture of these.

When the protective layer contains a silicone resin, the silicone resin is preferably a hydrolysis-condensation product obtained by hydrolyzing a mixture obtained by mixing two or more compounds represented by formula (1), from the viewpoint of further suppressing surface cracks.

The ratio of the amount of the compound represented by the formula (1) to be used is not particularly limited, but the ratio of the amount of the most abundant compound to the amount of the second most abundant compound is preferably 100/1 or less, more preferably 20/1 or less. The lower limit is not particularly limited as long as 1/1 or more is used.

As the protective layer, for example, a layer or a hard coat film containing a known hard coat agent described in japanese patent application laid-open nos. 2018-202696, 2018-183877, and 2018-111793 may be used. In addition, from the viewpoint of heat storage properties, a protective layer containing a polymer having heat storage properties as described in international publication No. 2018/207387 and japanese patent application laid-open No. 2007-031610 may be used.

The protective layer may contain other components than the resin. Examples of the other components include a curing agent, a viscosity modifier (thickener), a thermally conductive material, an ultraviolet absorber, an antioxidant, and a preservative.

The protective layer preferably has flexibility that is less likely to cause cracking and hard coating properties that are less likely to be scratched. From these viewpoints, the protective layer preferably contains at least a curing agent, a crosslinking agent, or a thermal initiator or a photoinitiator. Further, the protective layer more preferably contains a curing agent from the viewpoint of excellent ignition resistance. Since the protective layer has the curing agent, a dense protective layer having a high crosslinking density can be formed.

Examples of the curing agent contained in the protective layer include reactive monomers, oligomers, and polymers (for example, acrylic resins, urethane resins, and rubbers) that are cured by heat or radiation. The curing agent preferably contains a curing agent that reacts with the resin contained in the protective layer, and examples thereof include melamine compounds, oxazoline compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, silane coupling compounds, and the like. Two or more of such curing agents may be used in combination. In addition, as a component to be cured together with such a curing agent, an arbitrary polymerizable monomer may be contained in the coating liquid.

The content of the curing agent in the protective layer is preferably 5 to 50 mass%, more preferably 10 to 40 mass%, with respect to the total mass of the protective layer.

The protective layer preferably contains a viscosity modifier from the viewpoint of excellent ignition resistance. The reason why the flame resistance of the heat storage member is improved by the viscosity modifier contained in the protective layer is not clear, but it is presumed that the leakage of the combustible gas to the outside can be suppressed because the minute gap between the heat storage layer and the adjacent layer such as the heat storage layer is filled.

The viscosity modifier contained in the protective layer is not particularly limited as long as it is a known viscosity modifier, but is preferably a water-soluble polymer or cellulose, and more preferably polyvinyl alcohol or Carboxymethyl cellulose (CMC), which are examples of a binder that can be contained in the heat-accumulative composition.

As the polyvinyl alcohol contained in the protective layer, commercially available products can be used, and examples thereof include Denka Poval series manufactured by Denka Company Limited (e.g., Denka PovalB-24 and B-33), KURARAY CO., and KURARAY POVAL series manufactured by LTD. (e.g., KURAY POVAL PVA-217E, KURAY POVAL KL-318).

When the viscosity modifier is polyvinyl alcohol, the degree of polymerization of the polyvinyl alcohol is preferably 500 to 5000, and more preferably 1000 to 3000.

The content of the viscosity modifier in the protective layer is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass, based on the total mass of the protective layer.

The thickness of the protective layer is not particularly limited, but is preferably 50 μm or less, more preferably 25 μm or less, further preferably 15 μm or less, and particularly preferably 10 μm, from the viewpoint of excellent heat storage properties and crack characteristics of the heat storage member. The lower limit is not particularly limited, but is preferably 0.1 μm or more, more preferably 1 μm or more, and even more preferably more than 3 μm, from the viewpoint of more excellent flame retardancy of the heat storage member.

In addition, from the viewpoint of excellent heat storage properties of the heat storage member, the ratio of the thickness of the protective layer to the thickness of the heat storage layer is preferably 1/10 or less, more preferably 1/20 or less, and still more preferably 1/40 or less. The lower limit is not particularly limited, but from the viewpoint of more excellent flame retardancy of the heat storage member, it is preferably 1/1000 or more, and more preferably 1/200 or more. By setting the thicknesses of the heat storage layer and the protective layer to the above ranges, it is possible to obtain excellent flame retardancy and ignition resistance while maintaining a high heat absorption amount.

The thickness of the protective layer was set to the following average value: the cut surface where the protective layer was cut in parallel with the thickness direction was observed by SEM, and the thickness at any 5 points was measured and averaged to obtain an average value of the thicknesses at 5 points.

The protective layer preferably has no cracks on a surface of the protective layer opposite to a surface facing the heat storage layer. Here, "crack is not present" means that when the surface of the protective layer is observed at a magnification of 200 times by SEM, no crack is observed. The ratio of crosslinking in the protective layer is adjusted according to the amount of the curing agent and the number of crosslinking points of the polymer precursor to be cured, thereby enabling adjustment of the crack characteristics of the protective layer. Furthermore, the occurrence of cracks can be suppressed by reducing the thickness of the protective layer. By forming the flexible protective layer without cracks, the heat storage member can be applied to a rolled form.

The method of forming the protective layer is not particularly limited, and known methods may be used. For example, a method of forming a coating film on a heat storage layer by bringing a protective layer-forming composition containing a resin or a precursor thereof into contact with the heat storage layer and, if necessary, curing the coating film, and a method of bonding a protective layer to the heat storage layer are given.

The resin contained in the protective layer forming composition is as described above. Examples of the composition for forming the protective layer include at least one composition selected from the group consisting of a fluorine atom-containing resin and a siloxane resin or a precursor thereof.

The precursor of the resin is a component that becomes a resin by curing treatment, and examples thereof include compounds represented by the above formula (1).

The protective layer-forming composition may contain a solvent (for example, water and an organic solvent) as needed. The composition for forming a protective layer preferably contains a flame retardant.

The method of bringing the composition for forming a protective layer into contact with the heat-storage layer is not particularly limited, and examples thereof include a method of applying the composition for forming a protective layer to the heat-storage layer, a method of immersing the heat-storage layer in the composition for forming a protective layer, and a method of applying the composition for forming a protective layer containing the viscosity-adjusting agent as a binder to the heat-storage layer to form a coating film.

In the method of forming a coating film by applying a protective layer forming composition containing a viscosity modifier (binder), the protective layer forming composition preferably further contains a solvent. When the composition for forming a protective layer contains a solvent, it is preferable to perform a drying step to evaporate the solvent from the coating film after the coating film is formed. The protective layer-forming composition containing a viscosity modifier (binder) may further contain an additive such as a surfactant, from the viewpoint of improving coatability.

Examples of the method for applying the composition for forming a protective layer include a method using a known application apparatus such as a dip coater, a die coater, a slit coater, a bar coater, an extrusion coater, a curtain coater, and a spray coater, and a printing apparatus such as gravure printing, screen printing, offset printing, and inkjet printing.

[ other layers ]

The heat storage member may have layers other than the heat storage layer and the protective layer.

< substrate >

The heat storage member may further have a base material, and preferably further has a base material.

Examples of the substrate include resin substrates such as polyesters (e.g., polyethylene terephthalate and polyethylene naphthalate), polyolefins (e.g., polyethylene and polypropylene), polyurethanes, glass substrates, and metal substrates. Further, it is also preferable that the action of rapidly diffusing heat from the heat generating portion to the heat accumulating portion is given to the base material by increasing the thermal conductivity in the plane direction or the film thickness direction. In this case, it is also preferable to combine a metal base material and a thermally conductive material such as a graphene sheet as the base material.

The thickness of the base material is not particularly limited and can be appropriately selected according to the purpose and circumstances. The thickness of the substrate is preferably larger from the viewpoint of handling, and the thickness of the substrate is preferably smaller from the viewpoint of the heat storage amount (the content in the heat storage layer of the microcapsule).

The thickness of the base material is preferably 1 to 100 μm, more preferably 1 to 25 μm, and further preferably 3 to 15 μm.

In order to improve the adhesion to the heat storage layer, the surface of the substrate is preferably treated. Examples of the surface treatment method include corona treatment, plasma treatment, and a method of providing a thin layer as an easy-adhesion layer.

The easy-adhesion layer preferably has hydrophilicity and hydrophobicity, affinity, and adhesion with the materials of both the heat storage layer and the base. The preferred material for the easy-adhesion layer varies depending on the material of the heat storage layer.

The material constituting the easy-adhesion layer is not particularly limited, but is preferably styrene-butadiene rubber, urethane resin, acrylic resin, silicone resin, or polyvinyl resin. When the substrate contains polyethylene terephthalate (PET) and the heat storage layer contains polyurethane, polyurea, or at least one selected from the group consisting of polyurethane, polyurea, and polyvinyl alcohol, styrene-butadiene rubber or a polyurethane resin can be preferably used as a material constituting the easy adhesion layer.

From the viewpoint of film strength and adhesion, a crosslinking agent is preferably introduced into the easy-adhesion layer. It is considered that an appropriate amount of the crosslinking agent is present in order to prevent the film itself from easily peeling due to cohesive failure and to prevent the film from being excessively hard from the viewpoint of adhesion. As the crosslinking agent, the same crosslinking agent as the above-mentioned curing agent is preferably used.

The easy-adhesion layer may contain two or more materials, including a material that easily adheres to the substrate and a material that easily adheres to the heat storage layer. The easy-adhesion layer may be a laminate of 2 or more layers including a layer that is easily adhered to the substrate and a layer that is easily adhered to the heat storage layer.

The thickness of the easy-adhesion layer is preferably large from the viewpoint of adhesion, but if the easy-adhesion layer is too thick, the heat storage amount of the entire heat storage member decreases. Therefore, the thickness of the easy adhesion layer is preferably 0.1 to 5 μm, and more preferably 0.5 to 2 μm.

< adhesion layer >

The substrate may have an adhesion layer on the side opposite to the side having the heat storage layer.

The adhesion layer is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include a layer containing a known adhesive (also referred to as an adhesive layer) and a layer containing an adhesive (also referred to as an adhesive layer).

Examples of the adhesive include acrylic adhesives, rubber adhesives, and silicone adhesives. Further, examples of the adhesive include an acrylic adhesive, an Ultraviolet (UV) -curable adhesive, and a silicone adhesive described in chapter 2 of "evaluation of characteristics of release paper, release film, and adhesive tape, and control technology thereof" (information agency, 2004).

The acrylic adhesive refers to an adhesive containing a polymer of a (meth) acrylic monomer ((meth) acrylic polymer).

Further, the adhesive layer may contain an adhesion-imparting agent.

Examples of the adhesive include a urethane resin adhesive, a polyester adhesive, an acrylic resin adhesive, an ethylene vinyl acetate resin adhesive, a polyvinyl alcohol adhesive, a polyamide adhesive, and a silicone adhesive. From the viewpoint of higher adhesion strength, a urethane resin adhesive or a silicone adhesive is preferable.

The method of forming the adhesion layer is not particularly limited, and examples thereof include a method of forming the adhesion layer by transferring the adhesion layer to a substrate, a method of forming the adhesion layer by applying a composition containing an adhesive or a bonding agent to a substrate, and the like.

The thickness of the adhesion layer is preferably 0.5 to 100 μm, more preferably 1 to 25 μm, and still more preferably 1 to 15 μm, from the viewpoint of adhesion, handling properties, and heat storage capacity.

A release sheet may be attached to one side of the adhesive layer opposite to the side facing the substrate. By attaching the release sheet, for example, when the microcapsule dispersion is applied to the substrate, the workability when the thickness of the substrate and the adhesion layer is thin can be improved.

The release sheet is not particularly limited, and for example, a release sheet in which a release material such as silicone is attached to a support such as PET or polypropylene can be suitably used.

[ physical Properties of Heat storage Member ]

< latent Heat Capacity >

The latent heat capacity of the heat storage member is preferably 105J/ml or more, more preferably 120J/ml or more, and even more preferably 130J/ml or more, from the viewpoint of high heat storage property and suitability for temperature control of the heat generating element. The upper limit is not particularly limited, but is usually 400J/ml or less.

The latent heat capacity is a value calculated from the measurement result of a Differential Scanning Calorimeter (DSC) and the thickness of the heat storage member.

In addition, from the viewpoint of achieving a high stored heat amount in a limited space, a stored heat amount in units of "J/ml (stored heat amount per unit volume)" is suitable, but the weight of electronic equipment is also important in applications such as electronic equipment. Therefore, from the viewpoint of exhibiting high heat storage performance within a limited mass, a heat storage amount in units of "J/g (heat storage amount per unit weight)" may be appropriate. In this case, the latent heat capacity of the heat storage member is preferably 120J/g or more, more preferably 140J/g or more, still more preferably 150J/g or more, and particularly preferably 160J/g or more. The upper limit is not particularly limited, but is usually 450J/g or less.

< tensile elongation at Break >

From the viewpoint of providing the heat storage member in a rolled form, the heat storage member preferably has high tensile strength and high elongation at tensile break. The elongation at tensile break is preferably 10% or more, more preferably 20% or more, and further preferably 30% or more. The upper limit is not particularly limited, but is usually 500% or less. The tensile strength is preferably 1MPa or more, more preferably 5MPa or more, and still more preferably 10MPa or more. The upper limit is not particularly limited, but is usually 100MPa or less, preferably 50MPa or less.

The tensile strength and elongation at tensile break of the heat storage member were measured according to the methods described in JIS K6251. Specifically, the heat storage sheet was cut out in a dumbbell-shaped 2-size shape, and a test piece with 2 marking lines was prepared with the distance between the initial marking lines set to 20 mm. The test piece was mounted on a tensile tester and stretched at a speed of 200mm/min to be broken. At this time, the maximum force (N) until breakage and the distance (mm) between the marking lines at the time of breakage were measured, and the tensile strength and the elongation at the time of tensile breakage were calculated by the following formulas.

The tensile strength TS (MPa) is calculated by the following equation.

TS＝Fm/Wt

Fm: maximum force (N)

W: width of parallel portion (mm)

t: thickness of parallel portion (mm)

The elongation Eb (%) at tensile break was calculated by the following formula.

Eb＝(Lb-L0)/L0×100

Lb: distance between marking lines at break (mm)

L0: initial mark line to line distance (mm)

[ electronic apparatus ]

An electronic device comprises the heat-accumulative composition, the heat-accumulative sheet and/or the heat-accumulative material.

The electronic device may have other components than the heat storage composition, the heat storage sheet, and the heat storage member. Examples of the other members include a heating element, a heat conductive material, a heat pipe, a vapor chamber (vapor chamber), an adhesive, and a base material. The electronic device preferably has at least one of a heat generating body and a heat conductive material, and more preferably has a heat generating body.

As one of preferable embodiments of the electronic device, there is a system including a heat storage sheet or a heat storage member, a heat conductive material disposed on the heat storage sheet or the heat storage member, a heat storage sheet in the heat conductive material, or a heat generating body disposed on a surface side opposite to the heat storage member.

The heat storage composition, the heat storage sheet, and the heat storage member of the electronic device are as described above.

[ heating body ]

The heat generating element is a component that generates heat in an electronic device, and examples thereof include a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an SoC (system on a Chip system) such as an SRAM (Static Random Access Memory) and an RF (Radio Frequency) device, a camera, an LED package, a power electronic device, and a battery (particularly, a lithium ion secondary battery).

The heat generating element may be disposed in contact with the heat storage member, or may be disposed in the heat storage member via another layer (for example, a heat conductive material described later).

[ Heat-conducting Material ]

The electronic device preferably further has a thermally conductive material.

The heat conductive material is a material having a function of transferring heat generated from the heat generating element to another medium.

By "thermal conductivity" of the thermally conductive material is meant a thermal conductivity of 10Wm^-1K^-1The above materials. Thermal conductivity (unit: Wm)^-1K^-1) Is a value measured by a flash method at a temperature of 25 ℃ by a method in accordance with Japanese Industrial Standard (JIS) R1611.

Examples of the heat conductive material include a metal plate, a heat sink, and silicone grease, and a metal plate or a heat sink is preferable.

The electronic device preferably includes the heat storage member, a heat conductive material disposed on the heat storage member, and a heat generating body disposed on a surface of the heat conductive material opposite to the heat storage member. Further, the electronic device preferably includes the heat storage member, a metal plate disposed on the heat storage member, and a heat generating body disposed on a surface side opposite to the heat storage member on the metal plate.

When the heat storage member has a protective layer, one preferable embodiment of the electronic device includes a heat storage member, a metal plate disposed on a surface of the heat storage member opposite to the protective layer, and a heat generating element disposed on a surface of the metal plate opposite to the heat storage member. In other words, the protective layer, the heat storage layer, the metal plate, and the heating element are preferably stacked in this order.

< Heat sink fins >

The heat sink is a sheet having a function of transferring heat generated from the heat generating element to another medium, and preferably has a heat dissipating material. Examples of the heat radiating material include carbon, metals (e.g., silver, copper, aluminum, iron, platinum, stainless steel, nickel, etc.), and silicon.

Examples of the heat sink sheet include a copper foil sheet, a metal plate, a metal-coated resin sheet, a metal-containing resin sheet, and a graphene sheet, and the graphene sheet is preferable. The thickness of the heat sink is not particularly limited, but is preferably 10 to 500 μm, and more preferably 20 to 300 μm.

[ Heat pipe, vapor chamber ]

The electronic device may also have a heat transport member selected from the group consisting of a heat pipe and a vapor chamber.

The heat pipe and the temperature equalizing plate are each formed of metal or the like, and each includes a member having a hollow structure and a working fluid as a heat transfer medium sealed in an internal space thereof, and the working fluid evaporates (vaporizes) in a high-temperature portion (an evaporation portion) to absorb heat, and the vaporized working fluid condenses in a low-temperature portion (a condensation portion) to release heat. The heat pipe and the temperature equalizing plate have a function of transferring heat from a member in contact with the high temperature portion to a member in contact with the low temperature portion by a phase change in the working fluid.

When the electronic device includes a heat storage member and a heat transport member selected from the group consisting of a heat pipe and a temperature equalization plate, the heat storage member is preferably in contact with the heat pipe or the temperature equalization plate, and more preferably in contact with a low-temperature portion of the heat pipe or the temperature equalization plate.

When the electronic device includes the heat storage member and the heat transport member selected from the group consisting of the heat pipe and the temperature equalization plate, it is preferable that the phase change temperature of the heat storage material contained in the heat storage layer overlaps with the temperature range in which the heat pipe or the temperature equalization plate operates. The temperature range in which the heat pipe or the vapor chamber operates includes, for example, a temperature range in which the working fluid can change its phase inside.

The material constituting the heat pipe and the vapor chamber is not particularly limited as long as it has high thermal conductivity, and metals such as copper and aluminum can be used.

Examples of the working fluid sealed in the inner space of the heat pipe and the vapor chamber include water, methanol, ethanol, and chlorofluorocarbon (CFC) substitutes, which can be appropriately selected and used in accordance with the temperature range of the electronic device to which the working fluid is applied.

[ other details ]

The electronic device may include other components than the protective layer, the heat storage layer, the metal plate, and the heat generating body. Examples of the other members include a heat sink, a base material, and an adhesive layer. The base material and the bonding layer are as described for the base material and the bonding layer that can be included in the heat storage member.

The electronic device may have at least one member selected from the group consisting of a heat sink, a base material, and an adhesion layer between the heat storage layer and the metal plate. When two or more members selected from the heat sink, the base material, and the adhesion layer are disposed between the heat storage layer and the metal plate, the base material, the adhesion layer, and the heat sink are preferably disposed in this order from the heat storage layer side toward the metal plate side.

The electronic device may further include a heat sink between the metal plate and the heat generating element.

Examples

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples as long as the invention does not depart from the gist thereof. Unless otherwise specified, "part(s)" and "%" are based on mass.

The particle diameter D50 and the wall thickness of the microcapsules were measured by the above-described method.

[ example 1]

(preparation of composition for Forming thermal storage layer)

72 parts by mass of eicosane (latent heat storage material; aliphatic hydrocarbon having a melting point of 37 ℃ and a carbon number of 20) was dissolved by heating at 60 ℃ to obtain a solution A1 to which 120 parts by mass of ethyl acetate was added.

To the stirred solution a1, 0.05 part by mass of N, N' -tetrakis (2-hydroxypropyl) ethylenediamine (ADEKA polyether EDP-300, ADEKA corporation) was added to obtain a solution B1.

To the stirred solution B1, 4 parts by mass of a trimethylolpropane adduct of toluene diisocyanate (BAROCKD-750, DIC CORPORATION) dissolved in 1 part by mass of methyl ethyl ketone was added to obtain a solution C1.

To 140 parts by mass of water was dissolved 7.4 parts by mass of Polyvinyl alcohol (KURARAY POVAL (registered trademark)) KL-318(KURARAY co., LTD, manufactured by PVA (Polyvinyl alcohol)) as an emulsifier, and the solution C1 was added to carry out emulsion dispersion to obtain an emulsion D1, 250 parts by mass of water was added to the emulsion D1, the obtained liquid was heated to 70 ℃ while stirring, and after stirring was continued for 1 hour, the liquid was cooled to 30 ℃, and water was added to the cooled liquid to adjust the concentration, thereby obtaining a microcapsule dispersion containing eicosane having a capsule wall of polyurethaneurea.

The solid content concentration of the microcapsule dispersion liquid containing eicosane was 14 mass%.

The mass of the capsule wall of the microcapsules containing eicosane was 6 mass% with respect to the mass of eicosane contained.

The median diameter D50 of the microcapsules on a volume basis was 20 μm. The thickness delta of the capsule wall of the microcapsules was 0.1 μm.

To 1000 parts by mass of the obtained microcapsule dispersion, 1.5 parts by mass of a side chain alkylbenzenesulfonate amine salt (NEOGEN T, DKS co.ltd.), 0.15 part by mass of 1, 2-bis (3, 3, 4, 4, 5, 5, 6, 6, 6-nonafluorohexyloxycarbonyl) ethanesulfonic acid sodium salt (W-AHE, manufactured by FUJIFILM Corporation) and 0.15 part by mass of a polyoxyalkylene alkyl ether (NOIGEN LP-90, DKS co.ltd.) were added and mixed to prepare a heat-accumulative composition 1 for forming a layer.

(production of polyethylene terephthalate (PET) substrate (1) with easy-to-bond layer and adhesive layer)

An optical adhesive sheet MO-3015 (thickness: 5 μm) manufactured by LINTEC Corporation was attached to a PET substrate having a thickness of 6 μm to form an adhesive layer.

On the surface of the PET substrate opposite to the surface having the adhesive layer, an aqueous solution prepared by mixing and dissolving Nippol Latex LX407C4E (manufactured by Zeon Corporation), Nippol Latex LX407C4C (manufactured by Zeon Corporation) and AQUABRID EM-13(Daicel Fine Chem Ltd) in a solid content concentration of 22: 77.5: 0.5 (mass basis) was applied. The obtained coating film was dried at 115 ℃ for 2 minutes to form an easy-adhesion layer made of a styrene-butadiene rubber-based resin having a thickness of 1.3 μm, thereby producing a PET substrate (1) having the easy-adhesion layer and the pressure-sensitive adhesive layer.

(preparation of composition for Forming protective layer 1)

The following ingredients were mixed, and the mixture was stirred for 12 hours, thereby preparing a composition 1 for forming a protective layer.

KYNAR Aquatec ARC (manufactured by Arkema Corp., solid content concentration: 44% by mass; fluorine-containing resin) 12.4 parts by mass

EPOCROS WS-700(NIPPON SHOKUBII CO., LTD., product: solid content concentration 25 mass%; oxazoline-based assimilating agent) 10.9 parts by mass

17.0 parts by mass of FUJI JET BLACK B-15(Fuji Pigment Co., Ltd., solid content concentration: 15% by mass; carbon BLACK)

5.1 parts by mass of Taien N (aqueous dispersion containing diammonium hydrogen phosphate and ammonium dihydrogen phosphate at a solid content concentration of 20% by mass, flame retardant, manufactured by Taihei Chemical Industrial Co., Ltd.)

1.4 parts by mass of NOIGEN LP-70 (aqueous solution having an isomer concentration of 2% by mass, manufactured by DKS Co. Ltd.; surfactant)

W-AHE (2% by mass concentration of the same body component manufactured by FUJIFILM Corporation; aqueous solution containing sodium 1, 2-bis (3, 3, 4, 4, 5, 5, 6, 6, 6-nonafluorohexyloxycarbonyl) ethanesulfonate; surfactant) 1.4 parts by mass

36.7 parts by mass of Denka Poval B-33 (aqueous solution containing polyvinyl alcohol having a solid content of 6.84% by mass, manufactured by Denka Company Limited., Ltd.; thickener)

15.1 parts by mass of pure water

(production of Heat-accumulative Member)

The heat storage layer-forming composition 1 prepared above was applied to the easy-adhesion layer side surface of the PET substrate (1) having the easy-adhesion layer and the pressure-sensitive adhesive layer by a bar coater so that the mass after drying became 143g/m²And the coated film was dried at 100 c for 10 minutes, thereby forming the heat storage layer 1 having a thickness of 190 μm.

Next, the protective layer forming composition 1 was applied to the surface of the heat storage layer 1 on the opposite side of the surface in contact with the easy-adhesion layer, and the coated film was dried at 45 ℃ for 2 minutes to form a protective layer 1 having a thickness of 3 μm.

Thus, a heat storage member 1 was produced in which an adhesive layer, a PET substrate (1), an easy-adhesion layer, a heat storage layer 1, and a protective layer 1 were sequentially laminated.

[ example 2]

To 1000 parts by mass of the microcapsule dispersion prepared by the method described in example 1 (preparation of composition for forming a heat-accumulative layer), 1.5 parts by mass of side chain alkylbenzenesulfonic acid amine salt (NEOGEN T, DKS Co. Ltd.) and 0.15 parts by mass of 1, 2-bis (3, 3, 4, 4, 5, 5, 6, 6, 6-nonafluorohexyloxycarbonyl) ethanesulfonic acid sodium salt (W-AHE, manufactured by FUJIFILM Corporation), 0.15 parts by mass of polyoxyalkylene alkyl ether (NOIGEN LP-90, DKS Co. Ltd.) and Taien N (Taihei Chemical Industrial Co., manufactured by Ltd.) were added and mixed an aqueous dispersion containing diammonium hydrogen phosphate and ammonium dihydrogen phosphate at a solid content of 20 mass%, and a flame retardant to prepare composition 2 for forming a heat-accumulative layer. The amount of Taien N used was adjusted so that the content of Taien N was 1.0 mass% based on the total solid content of heat storage layer-forming composition 2.

A heat storage member 2 in which a pressure-sensitive adhesive layer, a PET substrate (1), an easy-adhesion layer, and the heat storage layer 2 were sequentially laminated was produced by the method described in example 1 (production of a heat storage member) except that the protective layer 1 was not formed and the heat storage layer 2 was formed using the heat storage layer-forming composition 2 instead of the heat storage layer-forming composition 1.

[ example 3]

A composition 2 for forming a protective layer was prepared by the method described in example 1 (preparation of composition 1 for forming a protective layer), except that an aqueous dispersion containing TMP (DAIHACHI CHEMICAL INDUSTRY C0., manufactured by LTD., trimethyl phosphate; flame retardant) at a solid content concentration of 20 mass% was used in place of Taien N used in example 1.

A heat storage member 3 in which a pressure-sensitive adhesive layer, a PET substrate (1), an easy-adhesion layer, a heat storage layer 1, and a protective layer 2 were sequentially laminated was produced by the method described in example 1, except that the protective layer forming composition 1 was replaced with the protective layer forming composition 2 obtained in the above.

[ example 4]

A heat-accumulative material 3 was prepared in accordance with the procedure described in example 2, except that an aqueous dispersion containing TMP (DAIHACHI CHEMICAL INDUSTRY co., ltd. system, trimethyl phosphate; flame retardant) at a solid content concentration of 20 mass% was used in place of Taien N used in the preparation of emulsion D2 in example 2 to prepare emulsion D3, and that emulsion D3 was used in place of emulsion D2.

Next, a heat storage member 4 in which an adhesive layer, a PET substrate (1), an easy-adhesion layer, and the heat storage layer 3 were sequentially laminated was prepared in the manner described in example 2, except that the heat storage layer 3 was formed using the heat storage layer forming composition 3 instead of the heat storage layer forming composition 2.

[ example 5]

A composition 3 for forming a protective layer was prepared by the method described in example 1 (preparation of composition 1 for forming a protective layer) except that 26.0 parts by mass of pure water was used instead of EPOCROS WS-700 used in preparation of composition 1 for forming a protective layer in example 1.

A heat storage member 5 in which a pressure-sensitive adhesive layer, a PET substrate (1), an easy-adhesion layer, a heat storage layer 1, and a protective layer 3 were sequentially laminated was produced by the method described in example 1, except that the protective layer forming composition 3 obtained in the above was used instead of the protective layer forming composition 1.

[ example 6]

A composition 4 for forming a protective layer was prepared by the method described in example 1 (preparation of composition 1 for forming a protective layer) except that 51.8 parts by mass of pure water was used instead of Denka Poval B-33 used in preparation of composition 1 for forming a protective layer in example 1.

A heat storage member 6 in which a pressure-sensitive adhesive layer, a PET substrate (1), an easy-adhesion layer, a heat storage layer 1, and a protective layer 4 were sequentially laminated was produced by the method described in example 1, except that the protective layer forming composition 4 obtained in the above was used instead of the protective layer forming composition 1.

[ example 7]

A heat-accumulative layer-forming composition 4 having a capsule wall of polyurethaneurea and containing microcapsules containing eicosane was prepared by the method described in example 1 (preparation of a heat-accumulative layer-forming composition), except that an emulsion D3 was used in place of the emulsion D1, and an emulsion D3 was obtained by adding the solution C1 prepared by the method described in example 1 (preparation of a heat-accumulative layer-forming composition) to a solution prepared by dissolving 33.0 parts by mass of polyvinyl alcohol (KURARAY POVAL (registered trademark) KL-318 (manufactured by KURARAY co., ltd.; pva (polyvinyl alcohol) emulsifier) in 627 parts by mass of water and emulsifying and dispersing the resulting solution.

A heat storage member 7 in which an adhesive layer, a PET substrate (1), an easy-adhesion layer, a heat storage layer 4, and a protective layer 1 were sequentially laminated was produced in the same manner as described in example 1 (production of a heat storage member) except that the heat storage layer 4 was formed using the heat storage layer forming composition 4 instead of the heat storage layer forming composition 1.

Comparative example 1

A heat storage member C1 in which an adhesive layer, a PET substrate (1), an easy-adhesion layer, and a heat storage layer 1 were sequentially stacked was produced by the method described in example 1 (production of a heat storage member) except that the protective layer 1 was not formed.

Comparative example 2

Composition 5 for forming a heat storage layer was prepared by the method for preparing composition 2 for forming a heat storage layer described in example 2, except that Taien K (aqueous dispersion containing diammonium polyphosphate at a solid content concentration of 20 mass%, manufactured by Taihei Chemical Industrial co., ltd.; flame retardant) was used in place of Taien N used in preparation of composition 2 for forming a heat storage layer in example 2.

A heat storage member C2 in which an adhesive layer, a PET substrate (1), an easy-adhesion layer, and a heat storage layer 5 were sequentially laminated was produced in the same manner as described in example 2, except that the heat storage layer 5 was formed using the heat storage layer-forming composition 5 instead of the heat storage layer-forming composition 2.

Comparative example 3

A composition 5 for forming a protective layer was prepared by the method described in example 1 (preparation of composition 1 for forming a protective layer), except that PX200 (aqueous dispersion having a solid content of 20 mass%, manufactured by Ltd., and containing 1, 3-phenylene bis (xylyl phosphate) and a flame retardant) was used in place of Taien N used in example 1.

A heat storage member C3 in which a pressure-sensitive adhesive layer, a PET substrate (1), an easy-adhesive layer, a heat storage layer 1, and a protective layer 5 were sequentially laminated was produced by the method described in example 1, except that the protective layer-forming composition 1 was replaced with the protective layer-forming composition 5 obtained in the above.

Comparative example 4

A heat storage layer-forming composition 6 was prepared in accordance with the method for preparing a heat storage layer-forming composition 2 described in example 2, except that PX200 (aqueous dispersion having a solid content of 20 mass%, manufactured by Taihei Chemical Industrial Co., Ltd., containing 1, 3-phenylene bis (xylyl phosphate); flame retardant) was used in place of Taien N used in preparation of the heat storage layer-forming composition 2 in example 2.

A heat storage member C4 in which an adhesive layer, a PET substrate (1), an easy-adhesion layer, and the heat storage layer 6 were sequentially laminated was produced in the same manner as described in example 2, except that the heat storage layer 6 was formed using the heat storage layer-forming composition 6 instead of the heat storage layer-forming composition 2.

[ evaluation ]

The following evaluations were performed on each of the heat storage members produced in examples 1 to 7 and comparative examples 1 to 4. The evaluation results are shown in tables 1 and 2 described below.

[ decision that a specific condition is satisfied ]

(measurement of gas Generation temperature Tr of flame retardant (measurement method C1))

The gas generation temperature Tr of each flame retardant contained in each heat storage member was measured according to the above-described measurement method C1.

First, the type and content of the flame retardant contained in the heat storage member were measured by the above-described methods. The contents of the flame retardant and the heat-accumulative material in the heat-accumulative member are shown in Table 1 below.

With respect to the weight change caused by heating of the flame retardant contained in the heat storage member, measurement was performed using TG-DTA under a nitrogen atmosphere and under a temperature rise condition of 10 ℃. Based on the measurement results, a relational expression (C1)) between the temperature T (° C) and the weight loss rate Δ ma (T) of the flame retardant was derived, and a temperature at which the weight loss rate Δ ma (T) reached 2 mass% was obtained as the gas generation temperature Tr.

As a result, the gas generation temperatures Tr of Taien N, TMP, Taien K and PX-200 used in the examples and comparative examples were 150 ℃, 45 ℃, 280 ℃ and 326 ℃, respectively.

(measurement of gas generation temperature Tc of specific part (measurement method C2))

The gas generation temperature Tr of the specific member obtained by removing the flame retardant and the specific solvent from the heat storage member was measured according to the above measurement method C2.

The weight change due to heating of the heat storage member in each of examples and comparative examples was measured using TG-DTA under a nitrogen atmosphere and under a temperature rise condition of 10 ℃ per minute. Based on the measurement results, a relational expression (C2)) between the temperature T (° C) and the weight loss rate Δ m3(T) of the heat storage member was derived.

Further, as a result of measuring each component contained in the heat storage member, no specific solvent was detected in the heat storage members of the examples and comparative examples.

A relational expression between the temperature T (DEG C.) and the weight loss rate Deltam 3(T) of the heat storage member and a relational expression between the temperature T (DEG C.) and the weight loss rate Deltama (T) of the flame retardant is derived, and a temperature at which the weight loss rate Deltamz (T) reaches 2 mass% is determined as the gas generation temperature Tc of the specific member.

As a result, in the heat storage members of the respective examples, the gas generation temperature Tr of the flame retardant was lower than the gas generation temperature Tc of the specific member (Tc-Tr > 0), and the condition C was satisfied.

On the other hand, in the heat storage members of comparative examples 1 to 3 using the flame retardant, the gas generation temperature Tr of the flame retardant was higher than the gas generation temperature Tc of the specific member (Tc-Tr < 0), and the condition C was not satisfied.

[ evaluation of flame retardancy ]

(ignition property)

Samples having dimensions of 12.5cm in length and 1.3cm in width were cut out from each heat storage member, and the samples were attached to 0.2mm thick aluminum plates so that the adhesive layers of the samples were in contact with the aluminum plates, thereby producing 3 aluminum plate-attached samples. The heat storage member side of each aluminum plate-attached sample was exposed to a flame in accordance with the method of UL94HB standard (Underwriters Laboratories Inc.) to confirm whether there was a fire. The ignition properties of the heat storage member were evaluated on the basis of the number of the ignition samples out of the 3 aluminum-attached plate samples, according to the following criteria.

4: none of the 3 attached sheet samples ignited.

3: 1 sample with an aluminum plate ignited.

2: 2 samples with attached aluminum plates were on fire.

1: 3 samples with attached aluminum plates were on fire.

(Nature-retaining property)

Samples of each heat storage member of 3 aluminum-attached plates were produced according to the method described in the above evaluation of ignitability. Two lines of marks 75mm apart are marked on each sample. The flame was contacted from the side of the aluminum plate of each aluminum plate-attached sample to ignite the thermal storage member as per the method of UL94HB standard (Underwriters Laboratories Inc.). The velocity (burning velocity) of the flame moving between the two marked lines marked on each sample was measured, and the flame retardance of each sample was evaluated based on the average value of the obtained burning velocities and the following criteria based on the standard of UL94 HB.

2: burning speed less than 75 mm/min, or diminishing inflammation before reaching the 2 nd mark line

1: the burning rate is more than 75 mm/min

[ evaluation of appearance before and after storage test ]

Each heat-accumulative material was stored at 90 ℃ and 10 RH% or less for 250 hours. Changes in appearance before and after the storage test were visually observed, and evaluation was made based on the following criteria from the observation results.

2: changes in color tone and/or surface reflection of the heat storage member were observed compared to before storage

1: no change in appearance was observed

(measurement of latent Heat Capacity)

The latent heat capacity per unit mass (unit: J/g) of the obtained heat storage member was calculated from the measurement result of a Differential Scanning Calorimeter (DSC) and the thickness of the heat storage layer.

(other evaluation)

(evaluation of crosslinked Structure)

The crosslinked structure of the protective layer was evaluated for each of the heat storage members of examples 1, 3, and 5 to 7 and comparative example 1 by the following method.

A sample having a 2cm square size was cut out from each heat storage member, and this sample was immersed in 50ml of water. After stirring with a stirrer for 10 minutes, a sample was taken out. Whether or not the protective layer remained on the surface of the sample taken out was visually confirmed, and the water solubility of the protective layer was evaluated according to the following criteria.

3: a protective layer remains.

2: a small amount of protective layer remains.

1: no protective layer remains.

The test was carried out in the same manner as described above except that 50ml of N, N-dimethylformamide was used instead of water, and the solvent solubility of the protective layer was evaluated in accordance with the following criteria.

3: a protective layer remains.

2: a small amount of protective layer remains.

1: no protective layer remains.

As a result of the above evaluation, the protective layers of the respective heat storage members were evaluated to have both "3" water solubility and solvent solubility, and had a structure that was insoluble in either water or a solvent, i.e., a crosslinked structure.

(evaluation of cracks)

The surfaces of the protective layers disposed on the outermost layers of the heat storage members produced in examples 1, 3, and 5 to 7 and comparative example 1 were observed at a magnification of 200 times using SEM. The cracks on the surface of the protective layer were evaluated based on the following criteria according to the state of the cracks on the surface of the protective layer.

3: the surface of the protective layer is free from cracks.

2: a small number of cracks were present on the surface of the protective layer.

1: the surface of the protective layer has many cracks.

As a result of the above evaluation, the evaluation was that the cracks on the surface of the protective layer in the protective layer of each heat storage member were all "3".

[ Table 1]

[ Table 2]

From the results shown in tables 1 and 2, it was confirmed that the heat storage member of the present invention satisfying condition C is excellent in flame retardancy and ignition resistance.

It was also confirmed that the heat-accumulative compositions of examples 1 to 7 produced in this example all satisfy the condition A, and have excellent flame resistance and flame retardance as described above.

Further, as is clear from comparison of examples 1 to 6 with example 7, when the content of the heat storage material is 65 mass% or more with respect to the total mass of the heat storage composition, the heat absorption amount and the flame retardancy are more excellent.

Further, as is clear from comparison of examples 1 and 3 with example 5, the flame resistance is more excellent if the protective layer has a curing agent.

Further, as is clear from comparison of examples 1 and 3 with example 6, the flame resistance is more excellent if the protective layer has a viscosity modifier.

Further, as is clear from comparison between examples 1 and 2 and examples 3 and 4, when a flame retardant is contained in the protective layer, the heat absorption amount and the flame retardancy are more excellent.

Industrial applicability

The heat storage composition, the heat storage sheet, and the heat storage member of the present invention can be suitably used for the following applications: for example, the heat storage/dissipation material can be suitably used as a heat storage/dissipation material for stable operation by maintaining the surface temperature of a heat generating portion in an electronic device in an arbitrary temperature range; building materials (e.g., flooring materials, roofing materials, wall materials, etc.) suitable for temperature control during sudden temperature rise during the daytime or during indoor heating; clothes (such as underwear, coats, cold protective clothing, gloves and the like) suitable for temperature adjustment according to changes of environmental temperature or body temperature changes during exercise or rest; bedding; and a waste heat utilization system for storing unnecessary waste heat and utilizing the waste heat as heat energy.