阅读说明：本技术 树脂发泡体、树脂发泡体片、粘合带、车辆用构件和建筑构件 (Resin foam, resin foam sheet, adhesive tape, vehicle member, and building member ) 是由 高桥克典 深谷重一 肥田知浩 于 2018-07-05 设计创作，主要内容包括：本发明的目的在于,提供柔软且赋形性优异的树脂发泡体、包含该树脂发泡体的树脂发泡体片、粘合带、车辆用构件和建筑构件。本发明是一种树脂发泡体,其为具有多个气泡的树脂发泡体,所述树脂发泡体含有聚乙烯醇缩醛和增塑剂,所述树脂发泡体的伸长应变为300％以上且50％压缩应力为70kPa以下。(An object of the present invention is to provide a resin foam which is flexible and has excellent shaping properties, a resin foam sheet containing the resin foam, an adhesive tape, a member for a vehicle, and a building member. The present invention is a resin foam having a plurality of cells, the resin foam containing a polyvinyl acetal and a plasticizer, and having an elongation strain of 300% or more and a 50% compressive stress of 70kPa or less.)

1. A resin foam characterized by having a plurality of cells,

the resin foam contains a polyvinyl acetal and a plasticizer, and has an elongation strain of 300% or more and a 50% compressive stress of 70kPa or less.

2. The resin foam according to claim 1, wherein the elongation strain is 400% or more and the 50% compressive stress is 30kPa or less.

3. The resin foam according to claim 1 or 2, which contains a binder.

4. A resin foam sheet comprising the resin foam according to claim 1, 2 or 3.

5. An adhesive tape comprising the resin foam sheet according to claim 4 and an adhesive layer formed on at least one surface of the resin foam sheet.

6. A member for a vehicle, characterized in that the resin foam of claim 1, 2 or 3, the resin foam sheet of claim 4 or the adhesive tape of claim 5 is used.

7. A building member using the resin foam according to claim 1, 2 or 3, the resin foam sheet according to claim 4 or the adhesive tape according to claim 5.

Technical Field

The present invention relates to a flexible resin foam having excellent shaping properties, a resin foam sheet containing the resin foam, an adhesive tape, a vehicle member, and a building member.

Background

Resin foams are lightweight, flexible, and excellent in impact resistance, sound insulation, and the like, and therefore are used in all applications such as vehicle members for automobiles, airplanes, ships, and the like, building members, electronic members, living members such as backing materials for carpets, and electric products for home use and office use (patent document 1 and the like). Among them, a resin foam having a high open cell content is said to be particularly excellent in flexibility.

However, the conventional resin foam has the following problems: when the desired shape is formed, the resin tends to be broken, and the formability is poor. For example, when a conventional resin foam is molded into a plate, the resin foam may be broken by stretching.

Disclosure of Invention

Problems to be solved by the invention

In view of the above-described situation, an object of the present invention is to provide a resin foam which is flexible and has excellent shaping properties, a resin foam sheet containing the resin foam, an adhesive tape, a member for a vehicle, and a building member.

Means for solving the problems

The present invention is a resin foam having a plurality of cells, the resin foam containing a polyvinyl acetal and a plasticizer, and having an elongation strain of 300% or more and a 50% compressive stress of 70kPa or less.

The present invention is described in detail below.

The present inventors have conducted extensive studies and, as a result, have found that: the present inventors have completed the present invention by providing a resin foam containing a polyvinyl acetal and a plasticizer, which has an elongation strain of 300% or more and a 50% compressive stress of 70kPa or less, and which is flexible and excellent in formability, and which does not cause breakage or the like even when it is formed into a sheet.

The resin foam of the present invention contains polyvinyl acetal and a plasticizer.

The polyvinyl acetal is not particularly limited as long as it is a polyvinyl acetal obtained by acetalizing polyvinyl alcohol with an aldehyde, and is preferably polyvinyl butyral. Further, 2 or more kinds of polyvinyl acetals may be used in combination as necessary.

The acetalization degree of the polyvinyl acetal preferably has a lower limit of 40 mol% and an upper limit of 85 mol%, more preferably has a lower limit of 60 mol%, and even more preferably has an upper limit of 75 mol%.

The preferable lower limit of the amount of the hydroxyl group in the polyvinyl acetal is 15 mol%, and the preferable upper limit is 40 mol%. When the amount of the hydroxyl group is within this range, the compatibility with the plasticizer becomes high.

The acetalization degree and the hydroxyl group amount can be measured according to JIS K6728 "polyvinyl butyral test method", for example.

The polyvinyl acetal can be produced by acetalizing polyvinyl alcohol with an aldehyde.

The polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate, and polyvinyl alcohol having a saponification degree of 70 to 99.8 mol% is usually used. The saponification degree of the polyvinyl alcohol is preferably 80 to 99.8 mol%.

The polymerization degree of the polyvinyl alcohol preferably has a lower limit of 500 and an upper limit of 4000. When the polymerization degree of the polyvinyl alcohol is 500 or more, the handling property of the obtained resin foam becomes excellent. When the polymerization degree of the polyvinyl alcohol is 4000 or less, the resin foam can be easily molded. The lower limit of the polymerization degree of the polyvinyl alcohol is more preferably 1000, and the upper limit thereof is more preferably 3600.

The aldehyde is not particularly limited, and an aldehyde having 1 to 10 carbon atoms is usually suitably used. The aldehyde having 1 to 10 carbon atoms is not particularly limited, and examples thereof include n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexanal, n-octanal, n-nonanal, n-decanal, formaldehyde, acetaldehyde, benzaldehyde, and the like. These aldehydes may be used alone, or 2 or more of them may be used in combination. Among them, from the viewpoint of easily designing the loss coefficient of the obtained resin foam to be high, aldehydes having 2 to 10 carbon atoms are preferable, n-butyraldehyde, n-hexanal, and n-valeraldehyde are more preferable, and n-butyraldehyde is particularly preferable.

The plasticizer is not particularly limited, and examples thereof include organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters; phosphoric acid plasticizers such as organic phosphoric acid plasticizers and organic phosphorous acid plasticizers. The plasticizer is preferably a liquid plasticizer.

The monobasic organic acid ester is not particularly limited, and examples thereof include glycol esters obtained by reacting a glycol with a monobasic organic acid.

Examples of the diol include triethylene glycol, tetraethylene glycol, and tripropylene glycol. Examples of the monobasic organic acid include butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid, nonanoic acid (n-nonanoic acid), decanoic acid, and the like. Among them, triethylene glycol dihexanoate, triethylene glycol di-2-ethylbutyrate, triethylene glycol di-n-caprylate, triethylene glycol di-2-ethylhexanoate, and the like are preferable.

The polybasic organic acid ester is not particularly limited, and examples thereof include ester compounds formed from polybasic organic acids such as adipic acid, sebacic acid, azelaic acid, and the like, and alcohols having a linear or branched structure of 4 to 8 carbon atoms. Among them, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate and the like are preferable.

The organic ester plasticizer is not particularly limited, and examples thereof include triethylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethylene glycol di-n-caprylate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol di-2-ethylbutyrate, 1, 3-propylene glycol di-2-ethylbutyrate, 1, 4-butylene glycol di-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylvalerate, and mixtures thereof, And 6 to 8 carbon number adipic acid esters such as tetraethylene glycol di-2-ethylbutyrate, diethylene glycol didecanoate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, oil-modified sebacic acid, a mixture of phosphate and adipate, a mixed type adipate prepared from an adipate, an alkyl alcohol having 4 to 9 carbon atoms and a cyclic alcohol having 4 to 9 carbon atoms, and adipic acid ester such as hexyl adipate.

The organic phosphoric acid plasticizer is not particularly limited, and examples thereof include tributoxyethyl phosphate, isodecylphenyl phosphate, triisopropyl phosphate, and the like.

Further, the plasticizer is preferably one which hardly causes hydrolysis and contains: triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutyrate (3GH), tetraethylene glycol di-2-ethylhexanoate (4GO), and dihexyl adipate (DHA). More preferably contains: tetraethylene glycol di-2-ethylhexanoate (4GO) and triethylene glycol di-2-ethylhexanoate (3 GO). Further preferably contains: triethylene glycol di-2-ethylhexanoate (3 GO).

The content of the plasticizer in the resin foam of the present invention is not particularly limited, and the lower limit is preferably 5 parts by weight, and the upper limit is preferably 60 parts by weight, based on 100 parts by weight of the polyvinyl acetal. When the content of the plasticizer is within this range, the shaping property can be exhibited, and the plasticizer does not bleed out of the resin foam. The lower limit of the content of the plasticizer is more preferably 20 parts by weight, and the upper limit is more preferably 55 parts by weight.

The resin foam of the present invention preferably further contains a binder. The resin foam of the present invention can exhibit adhesiveness and improve handling properties by containing a binder.

The adhesive is not particularly limited, and examples thereof include known adhesives such as acrylic adhesives, urethane adhesives, and rubber adhesives.

The resin foam of the present invention may contain additives such as an adhesive strength adjuster, a heat ray absorber, an ultraviolet shielding agent, an antioxidant, a light stabilizer, and an antistatic agent, in addition to the polyvinyl acetal and the plasticizer. In addition, pigments such as carbon black, dyes, and the like may be contained to adjust the appearance of the obtained resin foam.

The resin foam of the present invention has an elongation strain of 300% or more and a 50% compressive stress of 70kPa or less.

In the present specification, the elongation strain means: the value represents the degree of deformation applied to a resin foam when an elongation deformation is applied to the resin foam molded into a sheet in a uniaxial direction. By setting the elongation strain to 300% or more, the resin foam of the present invention can exhibit excellent impact resistance. The elongation strain is preferably 400% or more, and more preferably 500% or more. The upper limit of the elongation strain is not particularly limited, and the upper limit is substantially about 800%.

In the present specification, the 50% compressive stress means: the value represents the stress applied to the resin foam when the resin foam molded into a sheet is compressed by 50% in the thickness direction. The resin foam of the present invention can exhibit excellent shaping properties by setting the 50% compressive stress to 70kPa or less. The 50% compressive stress is preferably 30kPa or less, more preferably 20kPa or less. The lower limit of the 50% compressive stress is not particularly limited, and the lower limit is substantially about 5 kPa.

The elongation strain and the 50% compressive stress can be measured by a method based on JIS K6767.

The elongation strain and 50% compressive stress can be achieved by adjusting the foaming state of the resin foam.

Specifically, for example, the open cell ratio of the resin foam is preferably 20% or more. By setting the open cell ratio to 20% or more, the 50% compressive stress of the obtained resin foam can be adjusted to a desired range, and extremely high flexibility can be exhibited. The open cell ratio is more preferably 30% or more, still more preferably 40% or more, and particularly preferably 50% or more. The upper limit of the above-mentioned continuous bubble rate is not particularly limited, and the upper limit is substantially about 98%.

In the present specification, the interconnected cells mean that cells forming the resin foam are connected to each other.

The above-mentioned open cell ratio is defined by the ratio of the volume of cells connected to the outside of the resin foam obtained by the size measurement to the apparent volume of the resin foam, and can be measured by the densitometry method described in JIS K7138 or the like.

The apparent density of the resin foam of the present invention is preferably 50kg/m³The above. By setting the apparent density to 50kg/m³As described above, the elongation strain of the resin foam can be adjusted to a desired range, and extremely good shaping properties can be imparted. The apparent density is more preferably 60kg/m³Above, more preferably 80kg/m³Above, particularly preferably 100kg/m³The above. The apparent density of the resin foam of the present invention is preferably 500kg/m³The following. By setting the apparent density to 500kg/m³Hereinafter, more excellent shaping properties can be exhibited. The apparent density is more preferably 300kg/m³Hereinafter, more preferably 200kg/m³The following.

The lower limit of the average cell diameter of the resin foam of the present invention is preferably 100 μm, and the upper limit is preferably 1000. mu.m. When the average cell diameter is within this range, higher flexibility and shaping properties can be exhibited. The average cell diameter is more preferably 120 μm at the lower limit, more preferably 500 μm at the upper limit, and still more preferably 200 μm at the lower limit.

The average cell diameter can be measured by observing the cell wall and the void by using a cross-sectional observation photograph of the cell, and measuring the size of the void.

The average aspect ratio of cells of the resin foam of the present invention is preferably 2 or less. By setting the average aspect ratio of the cells to 2 or less, higher flexibility and shape-imparting properties can be exhibited. The average aspect ratio of the bubbles is more preferably 1.5 or less.

The average aspect ratio of the bubbles can be measured by measuring the major axis and the minor axis of the voids by using a cross-sectional observation photograph of the bubbles and calculating the ratio of the major axis and the minor axis.

The method for producing the resin foam of the present invention is not particularly limited, and is preferably a method in which, for example, a thermal decomposition type foaming agent is added to the polyvinyl acetal, the plasticizer, and an additive added as needed to prepare a resin composition, and the resin composition is heated to a foaming temperature to decompose the thermal decomposition type foaming agent.

Here, in order to adjust the elongation strain and 50% compressive stress to desired ranges and to exhibit extremely high formability while setting the open cell fraction to 20% or more, the type and amount of the thermal decomposition type foaming agent to be used in production and the setting of the foaming temperature are extremely important. Among them, the setting of the foaming temperature is necessary for achieving a high open cell ratio.

The foaming temperature is preferably 180 ℃ or higher. It can be considered that: when the temperature is 180 ℃ or higher, the resin composition is sufficiently softened during foaming and cells are easily connected to each other, so that open cells are easily generated. In the resin composition containing a resin other than polyvinyl acetal, such an increase in the ratio of open cells is not observed even if the foaming temperature is increased, and therefore, it seems a phenomenon unique to the resin composition containing polyvinyl acetal and a plasticizer.

The thermal decomposition type foaming agent is not particularly limited as long as it has a decomposition temperature of about 120 to 240 ℃, and conventionally known thermal decomposition type foaming agents can be used. In addition, from the viewpoint of further improving the above-mentioned open cell ratio, it is preferable to use a thermal decomposition type foaming agent having a decomposition temperature higher by 20 ℃ or more than the molding temperature of the resin composition as a raw material before foaming, and it is more preferable to use a thermal decomposition type foaming agent having a decomposition temperature higher by 50 ℃ or more.

Specific examples of the thermal decomposition type foaming agent include azodicarbonamide, N '-dinitrosopentamethylenetetramine, 4' -oxybis (benzenesulfonylhydrazide), urea, sodium hydrogen carbonate, and a mixture thereof.

Examples of commercially available products among the above thermal decomposition type foaming agents include CELLMIC series (manufactured by sanko chemical industries, Ltd.), VINIFOL series, cellulan series, and neocellbond series (manufactured by henceforth chemical industries, Ltd.).

The amount of the thermal decomposition type foaming agent to be blended in the resin composition is not particularly limited, and the lower limit is preferably 3 parts by weight, and the upper limit is preferably 20 parts by weight, based on 100 parts by weight of the polyvinyl acetal. When the amount of the thermal decomposition type foaming agent is within this range, a foam having an open cell content of 10% or more can be produced. The lower limit of the amount of the thermal decomposition type foaming agent is more preferably 5 parts by weight, and the upper limit is more preferably 15 parts by weight.

The resin foam of the present invention, having the above-described structure, is flexible and exhibits extremely high shaping properties that cannot be achieved by conventional resin foams. Therefore, the resin foam of the present invention can be used in all applications such as vehicle members for automobiles, airplanes, ships, and the like, building members, electronic members, living members such as backing materials for carpets, and electric products for home use and office use. In particular, the resin foam of the present invention molded into a sheet shape can be used in a wide range of applications.

A resin foam sheet comprising the resin foam of the present invention is also one of the present invention.

The pressure-sensitive adhesive tape having the pressure-sensitive adhesive layer formed on at least one surface of the resin foam sheet of the present invention is extremely excellent in handling properties.

An adhesive tape comprising the resin foam sheet of the present invention and an adhesive layer formed on at least one surface of the resin foam sheet is also one aspect of the present invention.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include known pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, and rubber pressure-sensitive adhesives.

In particular, since the resin foam sheet of the present invention contains a plasticizer, there is a possibility that the adhesive force is reduced by the plasticizer transferring to the pressure-sensitive adhesive layer. Therefore, as the pressure-sensitive adhesive layer, a pressure-sensitive adhesive layer having high plasticizer resistance is preferably used.

Examples of the pressure-sensitive adhesive layer having high plasticizer resistance include a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing an acrylic polymer (X), a tackifier resin (Y) having a softening point of 140 to 160 ℃, and a crosslinking agent (Z). By using such an adhesive composition, the adhesive force is less likely to be reduced with time due to the transfer of the plasticizer.

Hereinafter, each component constituting the adhesive composition will be described in detail.

The acrylic polymer (X) is a polymer obtained by polymerizing a monomer mixture containing 5 to 18 parts by weight of a carboxyl group-containing monomer (B) per 100 parts by weight of an alkyl (meth) acrylate monomer (A) containing 60% by weight or more of an alkyl (meth) acrylate monomer (a) having 4 or less carbon atoms.

In the present specification, (meth) acrylic acid means acrylic acid or methacrylic acid, and (meth) acrylate means acrylate or methacrylate.

The alkyl (meth) acrylate monomer (a) preferably contains 60% by weight or more of an alkyl (meth) acrylate monomer (a) having an alkyl group and 4 or less carbon atoms. When the content of the alkyl (meth) acrylate monomer (a) having an alkyl group of 4 or less carbon atoms is 60% by weight or more, the plasticizer resistance of the obtained pressure-sensitive adhesive layer is increased. The content of the alkyl (meth) acrylate monomer (a) is more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 100% by weight, from the viewpoint of suppressing a decrease in adhesive force to the flexible polyvinyl chloride.

Specific examples of the alkyl (meth) acrylate monomer (a) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and t-butyl (meth) acrylate. These alkyl (meth) acrylate monomers (a) may be used alone or in combination of 2 or more. Among them, n-butyl (meth) acrylate is preferably contained, and more preferably, only n-butyl (meth) acrylate alone is contained.

The alkyl (meth) acrylate monomer (a) may contain an alkyl (meth) acrylate monomer (b) in which the number of carbon atoms in the alkyl group is 5 or more.

Specific examples of the alkyl (meth) acrylate monomer (b) include 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate.

The content of the alkyl (meth) acrylate monomer (a) when it contains the alkyl (meth) acrylate monomer (b) is preferably 20% by weight or less, and more preferably 10% by weight or less.

The carboxyl group-containing monomer (B) is a polymerizable monomer having a carboxyl group in the molecule, and is preferably a carboxyl group-containing vinyl monomer.

Specific examples of the carboxyl group-containing monomer (B) include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. These carboxyl group-containing monomers (B) may be used alone or in combination of 2 or more. Among them, (meth) acrylic acid is preferable, and acrylic acid is more preferable.

The monomer mixture to be the raw material of the acrylic polymer (X) may further contain other monomers in addition to the alkyl (meth) acrylate monomer (a) and the carboxyl group-containing monomer (B).

Examples of the other monomer include monomers containing a polar group other than a carboxyl group, styrene monomers such as styrene, α -methylstyrene, o-methylstyrene and p-methylstyrene, and the like.

The content of the carboxyl group-containing monomer (B) in the monomer mixture to be a raw material of the acrylic polymer (X) is preferably 5 parts by weight at the lower limit and 18 parts by weight at the upper limit with respect to 100 parts by weight of the alkyl (meth) acrylate monomer (a). By using 5 parts by weight or more of the carboxyl group-containing monomer (B), the plasticizer resistance of the resulting pressure-sensitive adhesive layer is increased. The content of the carboxyl group-containing monomer (B) is more preferably 6 parts by weight at the lower limit, more preferably 17 parts by weight at the upper limit, still more preferably 10 parts by weight at the lower limit, and still more preferably 15 parts by weight at the upper limit.

The lower limit of the weight average molecular weight of the acrylic polymer (X) is preferably 55 ten thousand, and the upper limit is preferably 100 ten thousand. If the weight average molecular weight is 55 ten thousand or more, the plasticizer resistance of the resulting adhesive layer becomes high. If the weight average molecular weight is 100 ten thousand or less, the pressure-sensitive adhesive layer can be inhibited from becoming excessively hard, and adhesive force can be exerted on an adherend having a complicated shape. The weight average molecular weight is more preferably 60 ten thousand at the lower limit, more preferably 80 ten thousand at the upper limit, still more preferably 65 ten thousand at the lower limit, and still more preferably 75 ten thousand at the upper limit.

The acrylic polymer (X) can be obtained by polymerizing the monomer mixture.

The polymerization method is not particularly limited, and examples thereof include a method of subjecting the monomer mixture to radical polymerization in the presence of a polymerization initiator. More specifically, a conventionally known polymerization method such as solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, or the like can be used.

The polymerization initiator is not particularly limited, and examples thereof include an organic peroxide-based polymerization initiator, an azo-based polymerization initiator, and the like.

Examples of the organic peroxide-based polymerization initiator include cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, stearoyl peroxide, o-chlorobenzoyl peroxide, acetyl peroxide, t-butyl hydroperoxide, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, 3, 5, 5-trimethylhexanoyl peroxide, t-butyl peroxy-2-ethylhexanoate, and di-t-butyl peroxide.

Examples of the azo polymerization initiator include 2, 2 '-azobisisobutyronitrile, 2' -azobis (2, 4-dimethylvaleronitrile), 4 '-azobis (4-cyanovaleric acid), and 2, 2' -azobis (2-methylbutyronitrile).

These polymerization initiators may be used alone, or 2 or more kinds thereof may be used in combination. Among them, lauroyl peroxide, octanoyl peroxide, stearoyl peroxide, and 3, 5, 5-trimethylhexanoyl peroxide are preferable from the viewpoint of reducing the odor of the resulting acrylic polymer (X).

The amount of the polymerization initiator is not particularly limited, and is preferably about 0.01 to 10 parts by weight, more preferably about 0.05 to 2 parts by weight, based on 100 parts by weight of the monomer mixture.

The softening point of the tackifier resin (Y) is preferably 140 ℃ at the lower limit and 160 ℃ at the upper limit. When the softening point is within the above range, deterioration of the adhesive strength of the resulting pressure-sensitive adhesive layer with time can be suppressed. From the viewpoint of further suppressing the decrease in the adhesive force with time, a more preferable upper limit of the softening point is 150 ℃.

The softening point of the tackifier resin (Y) may be measured according to JIS K2207.

Examples of the tackifier resin (Y) include rosin resins such as petroleum resin-based tackifier resin, hydrogenated petroleum resin-based tackifier resin, rosin glycol-based tackifier resin, and rosin ester-based tackifier resin, terpene resins, phenol resins, xylene resins, coumarone resins, ketone resins, and modified resins thereof. These tackifying resins may be used alone or in combination of 2 or more. Among these, rosin-based tackifying resins are preferable, and rosin ester-based tackifying resins are more preferable, from the viewpoint of suppressing the adhesive force with time.

Examples of the rosin ester-based tackifying resin include disproportionated rosin ester, polymerized rosin ester, hydrogenated rosin ester, rosin phenol-based resin, and the like.

The content of the component having a molecular weight of 600 or less in the tackifier resin (Y) is preferably 13% by weight or less. When such a tackifier resin is used, the volatile components generated from the tackifier resin can be suppressed to a low level while maintaining the tackiness. Further, since the low-molecular weight component is small, the viscosity of the pressure-sensitive adhesive layer can be relatively increased, and the movement of the plasticizer to the pressure-sensitive adhesive layer is easily inhibited, so that the deterioration of the adhesive strength with time is less likely to occur.

Examples of the method for removing the component having a molecular weight of 600 or less from the tackifier resin include a method of heating and melting the tackifier resin to a softening point or higher, and a method of blowing steam.

The molecular weight and the content of the tackifier resin can be measured by Gel Permeation Chromatography (GPC), and calculated from polystyrene conversion values and area ratios.

The amount of the tackifier resin (Y) blended in the pressure-sensitive adhesive composition is preferably 3 parts by weight at the lower limit and 9 parts by weight at the upper limit with respect to 100 parts by weight of the acrylic polymer (X). When the amount of the tackifier resin blended is 3 parts by weight or more, the adhesive strength to a hardly adhered object is improved. When the blending amount of the tackifier resin is 9 parts by weight or less, the plasticizer can be easily prevented from moving to the pressure-sensitive adhesive layer, and the deterioration of the adhesive strength with time can be prevented. From the viewpoint of improving the adhesive force to the difficult-to-adhere object and maintaining the adhesive force, the blending amount of the tackifier resin (Y) is more preferably 4 parts by weight at the lower limit, more preferably 8 parts by weight at the upper limit, and still more preferably 7 parts by weight at the upper limit.

The crosslinking agent (Z) has an effect of improving the cohesive force of the obtained pressure-sensitive adhesive layer and improving the physical properties of the pressure-sensitive adhesive tape.

The crosslinking agent (Z) is not particularly limited, and examples thereof include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, and a metal chelate-based crosslinking agent. Among them, an isocyanate-based crosslinking agent or a metal chelate-based crosslinking agent is preferable.

Specific examples of the isocyanate crosslinking agent include toluene diisocyanate, naphthalene-1, 5-diisocyanate, and diphenylmethane diisocyanate. Examples of commercially available products include CORONATE L manufactured by polyurethane corporation, japan.

Specific examples of the metal chelate-based crosslinking agent include chelate compounds in which a metal atom is aluminum, zirconium, titanium, zinc, iron, tin, or the like. Among them, an aluminum chelate compound in which the central metal is aluminum is preferable. Commercially available products include aluminum chelate compound A and aluminum chelate compound M manufactured by Kagawa Fine chemical Co.

The content of the crosslinking agent (Z) in the pressure-sensitive adhesive composition is not particularly limited, and the lower limit is preferably 0.005 parts by weight, the upper limit is preferably 5 parts by weight, the lower limit is more preferably 0.01 parts by weight, the upper limit is more preferably 1 part by weight, the lower limit is more preferably 0.02 parts by weight, and the upper limit is more preferably 0.1 parts by weight, based on 100 parts by weight of the acrylic polymer (X).

The pressure-sensitive adhesive composition may contain a solvent such as ethyl acetate, dimethyl sulfoxide, ethanol, acetone, or diethyl ether in addition to the acrylic polymer (X), the tackifier resin (Y), and the crosslinking agent (Z). Among them, ethyl acetate is preferable from the viewpoint of suppressing the volatile component to a low level.

The pressure-sensitive adhesive composition may further contain additives such as fillers, pigments, dyes, and antioxidants, if necessary.

The lower limit of the thickness of the pressure-sensitive adhesive layer is preferably 5 μm, and the upper limit is preferably 200 μm. When the thickness of the pressure-sensitive adhesive layer is within this range, sufficient pressure-sensitive adhesive properties can be exhibited. The lower limit of the thickness of the pressure-sensitive adhesive layer is more preferably 7 μm, the upper limit is more preferably 150 μm, the lower limit is more preferably 10 μm, and the upper limit is more preferably 100 μm.

The method for producing the adhesive tape of the present invention by forming an adhesive layer on at least one surface of the resin foam sheet of the present invention is not particularly limited, and examples thereof include a method of applying an adhesive to at least one surface of a resin foam sheet using an applicator such as a coater; a method of spraying and applying the adhesive using a sprayer; a method of coating an adhesive using bristles, and the like. The pressure-sensitive adhesive layer may be formed by a method of bonding a double-sided pressure-sensitive adhesive tape to at least one side of the resin foam sheet.

The resin foam, the resin foam sheet, and the pressure-sensitive adhesive tape of the present invention are flexible and have excellent formability, and therefore can be used in all applications such as vehicle members for automobiles, airplanes, ships, and the like, building members, electronic members, living members such as backing materials for carpets, and electric products for home use and office use.

Examples of the living member include members for the purpose of damping vibration, impact, sound, and the like, such as a carpet backing material, a curtain material, and wallpaper.

Examples of the electric component include electronic components such as a mobile phone, a tablet computer, and a personal computer; members used for the purpose of reducing vibration, impact, sound, and the like in home electric appliances such as audio equipment, headphones, televisions, refrigerators, washing machines, and vacuum cleaners, and in office electric appliances.

Examples of the members for other uses include members used for the purpose of mitigating impact at the time of collision, such as floors, mats, and walls in indoor and outdoor sports facilities.

The resin foam, the resin foam sheet, and the adhesive tape of the present invention are particularly suitable as a vehicle member and a building member.

A member for a vehicle using the resin foam, the resin foam sheet, or the adhesive tape of the present invention is also one aspect of the present invention.

A building member using the resin foam, the resin foam sheet, or the adhesive tape of the present invention is also one aspect of the present invention.

Examples of the vehicle member include members for the purpose of damping vibration, impact, sound, and the like, such as a ceiling material, an interior material, and an interior lining material of a vehicle such as an automobile, an airplane, and a ship.

More specifically, examples of the damping material include a damping material used by being directly attached to a steel plate member such as a ceiling, a door panel, or a floor of a vehicle such as an automobile; a shock absorbing material, a cushioning material, or the like used by being sandwiched between a steel plate member constituting an exterior trim or a frame and a resin member constituting an interior trim.

Examples of the building member include members for the purpose of damping vibration, impact, sound, and the like, such as floor base materials, materials for sound-insulating walls, ceiling materials, and lining materials of resin-made and metal-made tiles.

More specifically, examples of the sound insulation mat include an attenuation material directly adhered to a metal tile including a GALVALUME steel sheet (registered trademark) as a measure against rain, and a sound insulation mat used by being sandwiched between a floor material and a base material of a house floor.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a resin foam which is flexible and has excellent shaping properties, a resin foam sheet containing the resin foam, an adhesive tape, a vehicle member, and a building member can be provided.

Detailed Description

The mode of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(example 1)

(1) Production of resin foam

To 100 parts by weight of polyvinyl butyral 1(PVB1), 40 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as a plasticizer, 8 parts by weight of VINIFOL AC #3 (manufactured by Yonghe chemical industries, Ltd., decomposition temperature 208 ℃ C.) as a thermal decomposition type foaming agent, and 0.8 parts by weight of carbon black (manufactured by Toshiba carbon Co., Ltd., SEAST SP) were added to obtain a resin composition. The obtained resin composition was sufficiently kneaded at 110 ℃ using an open roll, and then extruded using an extruder to obtain a sheet-like body. The hydroxyl group content of PVB1 was 31 mol%, the degree of acetylation was 0.7 mol%, the degree of butyralization was 68.3 mol%, and the average degree of polymerization was 1800.

The obtained sheet-like body was decomposed by a thermal decomposition type foaming agent in an oven at a foaming temperature of 230 ℃, thereby obtaining a sheet-like resin foam (resin foam sheet).

(2) Measurement of continuous bubble Rate and apparent Density

The open cell ratio of the obtained resin foam was measured by a densitometry method in accordance with JIS K7138. The apparent density was measured by a method of calculating from the measured weight and the apparent volume obtained by the dimension measurement.

(3) Measurement of average cell diameter and average aspect ratio of cells

A sample of the resin foam for measurement was cut into a length of 50mm, a width of 50mm, and a thickness of 4mm, immersed in liquid nitrogen for 1 minute, and then cut with a blade along a plane parallel to the thickness direction.

Thereafter, a photograph was taken at 200-magnification using a digital microscope (product name: VHX-900, manufactured by Kinzhi Co., Ltd.), and the diameters of all the bubbles present in a cross section having a length of 2mm in the thickness direction were measured.

The measurement site was changed and the operation was repeated 5 times, and the average value of all the observed cell diameters was defined as the average cell diameter. The bubble diameter of each bubble is defined as the diameter of an inscribed circle having the largest diameter when the inscribed circle inscribed in the observed bubble is drawn.

When the average bubble diameter is measured, the major axis and the minor axis of an ellipse inscribed in each observed bubble are measured, and the aspect ratio is determined by dividing the length of the major axis by the length of the minor axis. The aspect ratio was determined for all the bubbles observed, and the average value of the obtained aspect ratios was determined.

(4) Measurement of elongation Strain and 50% compression stress

The elongation strain and 50% compressive stress were measured by a method based on JIS K6767.

Specifically, the elongation strain was measured by a method of drawing a dumbbell 1-shaped sample punched out in a manner prescribed in JIS K6251 at a drawing speed of 500 mm/min using a universal testing machine.

Further, a sample cut into a square with a 50mm side was laminated until the lamination thickness reached 25mm or more, and the laminated sample thus obtained was subjected to compression at a compression rate of 10 mm/min by a universal testing machine, and the 50% compressive stress was measured.

(examples 2 to 4)

A resin foam was produced in the same manner as in example 1 except that the blending amount of the thermal decomposition type foaming agent was changed as shown in Table 1, and the elongation strain, 50% compression stress and the like were measured.

(examples 5 to 7)

A resin foam was produced in the same manner as in example 1 except that polyvinyl butyral 2(PVB2) was used in place of polyvinyl butyral 1 and the amount of the thermal decomposition type foaming agent was changed as shown in table 1, and the elongation strain, 50% compressive stress, and the like were measured. The content of hydroxyl groups in PVB2 was 22.0 mol%, the degree of acetylation was 4.0 mol%, the degree of butyralization was 74.0 mol%, and the average degree of polymerization was 550.

Comparative example 1

As a comparative example, a commercially available polyethylene foam (SoFTLON S, 5-fold expansion ratio, manufactured by WATERPOWDER CHEMICAL CO., Ltd.) was prepared. The polyethylene foam was subjected to the measurement of elongation strain, 50% compressive stress and the like in the same manner as in example 1.

Comparative example 2

As a comparative example, a commercially available polyethylene foam (SoFTLON S, manufactured by WATERPOWDER CHEMICAL Co., Ltd., expansion ratio: 10) was prepared. The polyethylene foam was subjected to the measurement of elongation strain, 50% compressive stress and the like in the same manner as in example 1.

Comparative example 3

As a comparative example, a commercially available polyethylene foam (SOFTLON S, manufactured by WATERPOWDER CHEMICAL INDUSTRIAL Co., Ltd., expansion ratio 15 times) was prepared. The polypropylene foam was subjected to measurement of elongation strain, 50% compressive stress and the like in the same manner as in example 1.

Comparative example 4

As a comparative example, a commercially available polyurethane foam (SUPER SHEET SS-H6, 15-fold expansion ratio, manufactured by JEOL Ltd.) was prepared. The polyurethane foam was subjected to the measurement of elongation strain, 50% compressive stress and the like in the same manner as in example 1.

(evaluation)

The resin foams obtained in examples 1 to 7 and comparative examples 1 to 4 were evaluated by the following method.

The results are shown in Table 1.

(1) Evaluation of formability

A foamed body having an adhesive material coated on one surface thereof was placed on a corrugated sheet made of polycarbonate having a pitch of 32mm and a valley depth of 9mm so as to contact only the crest portions of the corrugated sheet, and the portions not contacted with the foamed body were stretched and adhered so as to be pressed against the valley portions. The presence or absence of breakage or local thinning of the foam body at this time was observed. The moldability of the resin foam was evaluated by the following criteria.

O: no breakage or thinning was observed

X: breakage or thinning was observed

(2) Evaluation of flexibility

SUS balls having a diameter of 1/2 inches were allowed to stand for 1 minute in the valleys of the foam formed into a corrugated sheet shape. It was observed whether there was a trace of sinking of the SUS ball when the SUS ball was removed. The flexibility of the resin foam was evaluated by the following criteria.

O: sink marks of SUS balls were observed

X: no trace was confirmed

[ Table 1]

(example 8)

A double-sided adhesive tape for fixing an interior member (product of waterlogging chemical industry, #5782) as an adhesive layer was bonded to one surface of the resin foam sheet obtained in example 1 to obtain a single-sided adhesive tape.

The obtained single-sided pressure-sensitive adhesive tape can exhibit adhesiveness while maintaining the flexibility and sound insulation properties of the resin foam sheet described in example 1.

(example 9)

(1) Production of acrylic Polymer

A monomer component was obtained by introducing 100 parts by weight of n-butyl acrylate and 11 parts by weight of acrylic acid into a reaction vessel. This monomer component was dissolved in ethyl acetate, 0.1 part by weight of lauroyl peroxide as a polymerization initiator was added at the reflux point, and the mixture was refluxed at 70 ℃ for 5 hours to obtain a solution of an acrylic polymer having a weight average molecular weight of 72 ten thousand.

(2) Adhesive composition and production of adhesive tape

To the obtained acrylic polymer solution, a polymerized rosin ester based tackifying resin (softening point 140 ℃) having a content of 13% of components having a molecular weight of 600 or less was added in an amount of 6.3 parts by weight and an aluminum chelate compound as a crosslinking agent and being a metal chelate crosslinking agent was added in an amount of 0.054 part by weight based on 100 parts by weight of the acrylic polymer, which is a nonvolatile component of the acrylic polymer solution. Thereafter, the mixture was uniformly mixed to obtain an adhesive composition.

Next, the obtained pressure-sensitive adhesive composition was applied to one surface of the resin foam sheet obtained in example 1, and then dried at 120 ℃ for 5 minutes to obtain a one-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer having a thickness of 60 μm was laminated on one surface of the resin foam sheet.

The obtained single-sided pressure-sensitive adhesive tape can exhibit adhesiveness while maintaining the flexibility and sound insulation properties of the resin foam sheet described in example 1.

(evaluation)

The single-sided pressure-sensitive adhesive tapes obtained in examples 8 and 9 were evaluated by the following methods.

(evaluation of plasticizer resistance)

(1) Preparation of test body

The one-sided pressure-sensitive adhesive tapes obtained in examples 8 and 9 were cut into a width of 25mm × a length of 150mm, and a 2kg rubber roller was reciprocated 1 time at a speed of 10 mm/sec in accordance with JIS Z0237 and pressure-bonded to SUS304 (surface BA finish) specified in JIS G4305.

(2) Determination of initial adhesion

The single-sided pressure-sensitive adhesive tape obtained by the preparation of the test piece was pressure-bonded at 23 ℃ and 50% RH, left to stand for 20 minutes, and then subjected to a 90-degree peel test in accordance with JIS Z0237 with the number of tests being 3, and the average value was defined as the initial adhesive force (N/25 mm). The peeling speed was 300 mm/min.

(3) Measurement of adhesion force with time

The test piece obtained by the preparation of the test piece was left at 60 ℃ for 72 hours in an atmosphere, then left at 23 ℃ and 50% RH for 30 minutes, and then subjected to 90-degree peel test with 3 test times according to JIS Z0237, and the average value was defined as the time-dependent adhesive force (N/25 mm).

(4) Evaluation of adhesive force maintenance ratio

The initial adhesive force and the adhesive force with time obtained above were used to calculate the adhesive force maintenance rate (%) using the following formula.

Adhesion force maintenance ratio (%) ═ 100 × (adhesion force with time/initial adhesion force)

The adhesive force maintenance ratio of the one-sided pressure-sensitive adhesive tape obtained in example 9 was greatly improved as compared with the adhesive force maintenance ratio of the one-sided pressure-sensitive adhesive tape obtained in example 8.

Industrial applicability

According to the present invention, a resin foam which is flexible and has excellent shaping properties, a resin foam sheet containing the resin foam, an adhesive tape, a vehicle member, and a building member can be provided.