阅读说明：本技术 片状粘接剂、密封片、电子器件的密封体和电子器件的密封体的制造方法 (Sheet-like adhesive, sealing sheet, electronic device sealing body, and method for producing electronic device sealing body ) 是由 长谷川树 西嶋健太 樫尾干广 于 2020-03-19 设计创作，主要内容包括：本发明提供：含有下述(A)成分、(B)成分和(C)成分的片状粘接剂；含有上述片状粘接剂的密封片；以及被密封物通过上述密封片密封而形成的密封体。本发明的片状粘接剂适合用作在高温条件下的形状保持性优异的固化物的形成材料。(A)成分：玻璃化转变温度(Tg)为110℃以上的苯氧树脂、(B)成分：多官能环氧树脂、(C)成分：光阳离子聚合引发剂。(The present invention provides: a sheet-like adhesive containing the following component (A), component (B) and component (C); a sealing sheet containing the sheet adhesive; and a sealing body formed by sealing the object to be sealed with the sealing sheet. The sheet-like adhesive of the present invention is suitably used as a material for forming a cured product having excellent shape retention under high-temperature conditions. (A) The components: a phenoxy resin having a glass transition temperature (Tg) of 110 ℃ or higher, and a component (B): a polyfunctional epoxy resin, and component (C): a photo cationic polymerization initiator.)

1. A sheet-like adhesive comprising the following components (A), (B) and (C):

(A) the components: a phenoxy resin having a glass transition temperature Tg of 110 ℃ or higher;

(B) the components: a multifunctional epoxy resin;

(C) the components: a photo cationic polymerization initiator.

2. A sheet-like adhesive according to claim 1, wherein at least 1 of the components (B) is a component (BL) having a content of 50% by mass or more based on the whole sheet-like adhesive,

(BL) component: a multifunctional epoxy resin that is liquid at 25 ℃.

3. The sheet adhesive according to claim 1 or 2, further comprising the following component (D):

(D) the components: a silane coupling agent having a long chain spacer.

4. The sheet-like adhesive according to any one of claims 1 to 3, which has a storage modulus at 80 ℃ of 500MPa or more after curing.

5. The sheet-like adhesive according to any one of claims 1 to 4, which is used for sealing an electronic device.

6. A sealing sheet comprising an adhesive layer comprising the sheet-form adhesive according to any one of claims 1 to 5 and a functional film.

7. An electronic device sealing body formed by sealing an electronic device with an adhesive cured layer, wherein the adhesive cured layer is a cured product of the sheet-like adhesive according to any one of claims 1 to 5.

8. The electronic device package according to claim 7, wherein said electronic device package is an optical device.

9. A method for producing a sealed body for an electronic device, comprising the following steps (b1) to (b 2):

step (b 1): a step of irradiating the adhesive layer of the sheet-like adhesive according to any one of claims 1 to 5 or the seal sheet according to claim 6 with ultraviolet rays to initiate a curing reaction;

step (b 2): and (c) attaching the sheet-like adhesive or the adhesive layer after the step (b1) to the electronic component.

Technical Field

The present invention relates to: a sheet-like adhesive suitable as a material for forming a cured product having excellent shape retention under high-temperature conditions, an encapsulating sheet comprising the sheet-like adhesive, an electronic device sealing body formed by encapsulating an electronic device with a cured product of the sheet-like adhesive, and a method for producing the electronic device sealing body.

Background

In recent years, organic EL elements have attracted attention as light-emitting elements that can emit light with high luminance by low-voltage direct-current driving.

However, the organic EL element has a problem that light emission characteristics such as light emission luminance, light emission efficiency, and light emission uniformity tend to be deteriorated with the lapse of time.

As a cause of the problem of the deterioration of the light emitting characteristics, it is considered that oxygen, moisture, or the like enters the inside of the organic EL element to deteriorate the electrode or the organic layer, and therefore the organic EL element is sealed with a sealing material to prevent the entry of oxygen or moisture.

For example, patent document 1 describes a sheet-like sealing material for a display element, which comprises: the light-emitting material comprises epoxy resin with the weight-average molecular weight of 100-500, epoxy resin with the weight-average molecular weight of 800-10000, epoxy resin with the weight-average molecular weight of 20000-100000, a specific photo cation polymerization initiator and a photosensitizer.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-159026.

Disclosure of Invention

Problems to be solved by the invention

As described in patent document 1, a sheet-like adhesive containing an epoxy resin is suitably used as a material for forming a sealing material.

However, according to the studies of the present inventors, it was found that: a cured product of an epoxy resin-containing sheet adhesive is deformed under high-temperature conditions, and the sealing performance may be significantly reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide: a sheet-like adhesive suitable as a material for forming a cured product having excellent shape retention under high-temperature conditions, an encapsulating sheet comprising the sheet-like adhesive, an electronic device encapsulating body formed by encapsulating an electronic device with a cured product of the sheet-like adhesive, and a method for producing an electronic device encapsulating body.

Means for solving the problems

In order to solve the above problems, the present inventors have conducted intensive studies on a sheet-like adhesive containing an epoxy resin. As a result, they found that: the present inventors have completed the present invention by using a phenoxy resin having a high glass transition temperature (Tg) as a binder resin to obtain a cured product having excellent shape retention under high-temperature conditions.

Thus, according to the present invention, there are provided the following sheet-like adhesives [1] to [5 ]; [6] the sealing sheet of (1); [7] a sealing body for electronic devices of the above [8 ]; and [9] and [10] a method for producing a sealing body for an electronic device.

[1] A sheet-like adhesive comprising the following components (A), (B) and (C):

(A) the components: a phenoxy resin having a glass transition temperature (Tg) of 110 ℃ or higher;

(B) the components: a multifunctional epoxy resin;

(C) the components: a photo cationic polymerization initiator.

[2] [1] the sheet-like adhesive agent, wherein at least 1 of the components (B) is a component (BL) having a content of 50% by mass or more of the component (BL) relative to the entire sheet-like adhesive agent,

(BL) component: a multifunctional epoxy resin that is liquid at 25 ℃.

[3] The sheet-like adhesive according to [1] or [2], which further contains the following component (D):

(D) the components: a silane coupling agent having a long chain spacer.

[4] The sheet-like adhesive according to any one of [1] to [3], which has a storage modulus at 80 ℃ of 500MPa or more after curing.

[5] The sheet-like adhesive according to any one of [1] to [4], which is used for sealing an electronic device.

[6] A sealing sheet comprising an adhesive layer comprising the sheet-form adhesive according to any one of [1] to [5] and a functional film.

[7] A sealed body of an electronic device, which is formed by sealing an electronic device with an adhesive cured layer, wherein the adhesive cured layer is a cured product of the sheet-like adhesive according to any one of [1] to [5 ].

[8] [7] the sealing body for an electronic device, wherein the sealing body for an electronic device is an optical device.

[9] A method for producing a sealed body for an electronic device, comprising the following steps (b1) to (b 2):

step (b 1): a step of irradiating the sheet-like adhesive according to any one of [1] to [5] or the adhesive layer of the seal sheet according to [6] with ultraviolet rays to initiate a curing reaction;

step (b 2): and (c) attaching the sheet-like adhesive or the adhesive layer after the step (b1) to the electronic component.

Effects of the invention

According to the present invention, there are provided a sheet-like adhesive suitable as a material for forming a cured product excellent in shape retention under high-temperature conditions, an encapsulating sheet having the sheet-like adhesive, an electronic device encapsulating body formed by encapsulating an electronic device with a cured product of the sheet-like adhesive, and a method for producing an electronic device encapsulating body.

Detailed Description

The invention is divided into the following: 1) the sheet-like adhesive, 2) the sealing sheet, and 3) the sealing body of the electronic device and the method for manufacturing the same will be described in detail.

1) Sheet-like adhesive

The sheet adhesive of the present invention comprises: the following component (A), (B) and (C):

(A) the components: a phenoxy resin having a glass transition temperature (Tg) of 110 ℃ or higher;

(B) the components: a multifunctional epoxy resin;

(C) the components: a photo cationic polymerization initiator.

The sheet-like adhesive is an adhesive which is non-flowable at room temperature (25 ℃) and is molded into a sheet shape. In the present invention, the sheet-like adhesive may be a short strip-like adhesive or a long (strip-like) adhesive.

[ (A) component ]

The sheet adhesive of the present invention contains, as the component (a), a phenoxy resin having a glass transition temperature (Tg) of 110 ℃ or higher (hereinafter, sometimes referred to as "phenoxy resin (a)").

The phenoxy resin is a polymer having a main chain of an addition polymerization structure of an aromatic diol and an aromatic diglycidyl ether. The phenoxy resin generally corresponds to a high molecular weight epoxy resin, and means an epoxy resin having a polymerization degree of about 100 or more.

When the sheet-like adhesive contains the phenoxy resin (a), a cured product of the sheet-like adhesive becomes a cured product having excellent shape retention under high-temperature conditions.

The phenoxy resin (a) is important in sufficiently exhibiting the properties of the component (B).

That is, as described later, it is preferable that the sheet-like adhesive contains a large amount of the component (B) from the viewpoint of adhesiveness of the sheet-like adhesive and the viewpoint of shape retention of a cured product of the sheet-like adhesive under high temperature conditions.

However, a sheet-like adhesive containing a large amount of component (B) has a problem that shape retention tends to be poor.

In particular, since a sheet-like adhesive containing the component (C) requires a certain amount of time until the completion of the curing reaction, it is necessary to improve the shape retention property when such a sheet-like adhesive contains a large amount of the component (B).

In this respect, since the sheet adhesive of the present invention contains the phenoxy resin (a), a certain shape can be maintained for a long period of time even when the component (B) is contained in a large amount.

The glass transition temperature (Tg) of the phenoxy resin (A) is 110 ℃ or higher, preferably 120 to 180 ℃, and more preferably 140 to 165 ℃.

When the glass transition temperature (Tg) of the phenoxy resin (a) is 110 ℃ or higher, the sheet-like adhesive can retain a certain shape for a long period of time. Further, the cured product of the sheet-like adhesive is excellent in shape retention under high-temperature conditions.

The glass transition temperature (Tg) of the phenoxy resin (a) can be measured using a differential scanning calorimetry analyzer in accordance with JIS K7121.

The phenoxy resin (A) has a weight average molecular weight (Mw) of usually 10,000 to 200,000, preferably 20,000 to 100,000, more preferably 30,000 to 80,000.

When the weight average molecular weight (Mw) of the phenoxy resin (a) is too small, the sheet adhesive tends to be difficult to hold in a certain shape. When the weight average molecular weight (Mw) of the phenoxy resin (a) is too large, the sheet adhesive tends to be poor in handling properties.

The weight average molecular weight (Mw) of the phenoxy resin (a) can be determined as a standard polystyrene equivalent by Gel Permeation Chromatography (GPC) using Tetrahydrofuran (THF) as a solvent.

The epoxy equivalent of the phenoxy resin (A) is preferably 5,000g/eq or more, more preferably 7,000g/eq or more. The value of the epoxy equivalent can be measured in accordance with JIS K7236.

As the phenoxy resin (a), there can be mentioned: bisphenol a-type phenoxy resin, bisphenol F-type phenoxy resin, bisphenol S-type phenoxy resin, copolymer-type phenoxy resin of bisphenol a-type and bisphenol F-type, bisphenol E-type phenoxy resin, naphthalene-type phenoxy resin, novolak-type phenoxy resin, biphenyl-type phenoxy resin, cyclopentadiene-type phenoxy resin, and the like.

These phenoxy resins (a) may be used alone in 1 kind, or in combination with 2 or more kinds.

The phenoxy resin (a) can be obtained by a method in which a bifunctional phenol is reacted with epihalohydrin to have a high molecular weight, or a method in which a bifunctional epoxy resin is subjected to addition polymerization with a bifunctional phenol.

The phenoxy resin (A) can be obtained, for example, by reacting a bifunctional phenol with epihalohydrin in the presence of an alkali metal hydroxide in an inert solvent at a temperature of 40 to 120 ℃. The phenoxy resin (A) can be obtained by heating a bifunctional epoxy resin and a bifunctional phenol in an organic solvent having a boiling point of 120 ℃ or higher, such as an amide solvent, an ether solvent, a ketone solvent, a lactone solvent, or an alcohol solvent, to 50 to 200 ℃ in the presence of a catalyst such as an alkali metal compound, an organophosphorus compound, or a cyclic amine compound, at a reaction solid content concentration of 50 wt% or less, to perform addition polymerization.

The bifunctional phenol is not particularly limited as long as it is a compound having 2 phenolic hydroxyl groups. Examples of the bifunctional phenols include: monocyclic difunctional phenols such as hydroquinone, 2-bromohydroquinone, resorcinol, catechol, and the like; bisphenols such as bisphenol a, bisphenol F, bisphenol AD and bisphenol S; dihydroxybiphenyls such as 4, 4' -dihydroxybiphenyl; dihydroxyphenyl ethers such as bis (4-hydroxyphenyl) ether; and compounds obtained by introducing (introducing) a linear alkyl group, a branched alkyl group, an aryl group, a methylol group, an allyl group, a cyclic aliphatic group, a halogen (e.g., tetrabromobisphenol a), a nitro group, or the like into the aromatic ring of the phenol skeleton; and polycyclic bifunctional phenols obtained by introducing a linear alkyl group, a branched alkyl group, an allyl group, a substituted allyl group, a cyclic aliphatic group, an alkoxycarbonyl group, or the like into a carbon atom located at the center of the bisphenol skeleton.

As the epihalohydrin, there may be mentioned: epichlorohydrin, epibromohydrin, epiiodohydrin, and the like.

In the present invention, a commercially available phenoxy resin (a) can also be used. Examples of the phenoxy resin (a) include: trade names manufactured by mitsubishi chemical: YX7200 (glass transition temperature: 150 ℃ C.), YX6954 (phenoxy resin having bisphenol acetophenone skeleton, glass transition temperature: 130 ℃ C.), etc.

The content of the phenoxy resin (a) is preferably 15 to 47 mass%, more preferably 25 to 45 mass%, relative to the entire sheet-like adhesive.

When the content of the phenoxy resin (a) is in the above range, the shape retention and adhesiveness of the sheet-like adhesive and the shape retention of the cured product under high-temperature conditions are maintained in a well-balanced manner.

[ (B) component ]

The sheet adhesive of the present invention contains a polyfunctional epoxy resin (hereinafter, sometimes referred to as a polyfunctional epoxy resin (B)) as the component (B).

"multifunctional" means having 2 or more epoxy groups in the molecule.

The weight average molecular weight (Mw) of the polyfunctional epoxy resin (B) is preferably 100 to 5,000, more preferably 200 to 4,000.

The weight average molecular weight (Mw) of the polyfunctional epoxy resin (B) can be determined as a standard polystyrene equivalent by Gel Permeation Chromatography (GPC) using Tetrahydrofuran (THF) as a solvent.

The epoxy equivalent of the polyfunctional epoxy resin (B) is preferably 100g/eq or more and 500g/eq or less, more preferably 115g/eq or more and 300g/eq or less. A cured product having excellent adhesive strength can be obtained by curing a sheet-like adhesive containing a polyfunctional epoxy resin (B) having an epoxy equivalent of 100 to 500 g/eq.

The content of the polyfunctional epoxy resin (B) is preferably 50% by mass or more, more preferably 52 to 70% by mass, and still more preferably 55 to 68% by mass, based on the whole sheet-shaped adhesive.

When the content of the polyfunctional epoxy resin (B) is within the above range, the shape retention and adhesiveness of the sheet adhesive and the shape retention of the cured product under high temperature conditions are maintained in a well-balanced manner.

Examples of the polyfunctional epoxy resin (B) include: aliphatic epoxy compounds (excluding alicyclic epoxy compounds), aromatic epoxy compounds, alicyclic epoxy compounds, and the like.

As the aliphatic epoxy compound, there may be mentioned: 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, triglycidyl ether of glycerol, triglycidyl ether of trimethylolpropane, tetraglycidyl ether of sorbitol, hexaglycidyl ether of dipentaerythritol, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, dicyclopentadiene dimethanol diglycidyl ether, and the like.

As the aromatic epoxy compound, there can be exemplified: glycidyl etherate or epoxy novolac resin of bisphenol a, bisphenol F, or a compound obtained by further adding alkylene oxide (alkylene oxide) to these compounds; polyglycidyl ethers of aromatic compounds having 2 or more phenolic hydroxyl groups such as resorcinol, hydroquinone, and catechol; glycidyl etherate of aromatic compound having 2 or more alcoholic hydroxyl groups such as phenyl dimethanol, phenyl diethanol, and phenyl dibutanol; glycidyl esters of polybasic acid aromatic compounds having 2 or more carboxylic acids such as phthalic acid, terephthalic acid, and trimellitic acid.

Examples of the alicyclic epoxy compound include: a polyglycidyl ether compound of a polyhydric alcohol having at least 1 or more alicyclic structures such as a hydrogenated product of bisphenol a, or an oxidized cycloolefin (cyclopentene oxide) compound such as a cyclohexene oxide-or cyclopentene oxide-containing compound obtained by epoxidizing a cyclohexene-or cyclopentene ring-containing compound with an oxidizing agent.

These polyfunctional epoxy resins (B) may be used alone in 1 kind, or in combination of 2 or more kinds. The polyfunctional epoxy resin (B) preferably contains an alicyclic epoxy compound from the viewpoint of preventing the sheet adhesive from being colored.

At least 1 kind of the polyfunctional epoxy resin (B) is preferably the following (BL) component.

(BL) component: a polyfunctional epoxy resin that is liquid at 25 ℃ (hereinafter, sometimes referred to as liquid polyfunctional epoxy resin (BL)).

"liquid at 25" means having fluidity at 25 ℃. The liquid polyfunctional epoxy resin (BL) preferably has a viscosity of 2 to 10000 mPas as measured at 25 ℃ and 1.0rpm with an E-type viscometer.

The sheet-like adhesive containing the component (A) tends to have poor adhesiveness. However, the sheet adhesive of the present invention has sufficient adhesiveness because it contains a liquid multifunctional epoxy resin (BL).

In addition to the above effects, the liquid polyfunctional epoxy resin (BL) tends to form a cured product having a high crosslinking density and further improve the shape retention of the cured product under high-temperature conditions, and therefore the sheet-like adhesive of the present invention is suitable as a material for forming a cured product having excellent shape retention under high-temperature conditions.

The content of the liquid multifunctional epoxy resin (BL) is preferably 50 mass% or more, more preferably 52 to 70 mass%, and further preferably 55 to 68 mass% with respect to the entire sheet-shaped adhesive.

By setting the amount of the liquid polyfunctional epoxy compound (BL) to 50 mass% or more based on the whole sheet-like adhesive, a sheet-like adhesive having more excellent adhesiveness can be efficiently obtained.

[ (C) ingredient ]

The sheet adhesive of the present invention contains a photo cation polymerization initiator as the component (C).

The sheet-like adhesive containing a photo cation polymerization initiator is excellent in versatility.

That is, since the sheet-like adhesive containing the photo radical polymerization initiator tends to complete the curing reaction in a short time, the method of using the sheet-like adhesive containing the photo radical polymerization initiator is generally limited to curing the sheet-like adhesive by irradiating light to the sheet-like adhesive after attaching the sheet-like adhesive to an object.

On the other hand, since the sheet-like adhesive of the present invention containing a photo cation polymerization initiator requires a certain amount of time until the curing reaction is completed, the sheet-like adhesive is not limited to the use of curing the sheet-like adhesive after the sheet-like adhesive is attached to an object, and the sheet-like adhesive may be attached to the object after the curing reaction is initiated.

In addition, the following problems may occur in the characteristics that a certain time is required until the curing reaction is completed: the sheet-like adhesive deforms until the curing reaction is completed, and the object cannot be fixed at the target position. In particular, a sheet adhesive containing a liquid polyfunctional epoxy resin (BL) tends to have high fluidity, and this problem is likely to occur.

In this respect, even when the sheet-like adhesive of the present invention contains a liquid polyfunctional epoxy resin (BL), since the phenoxy resin (a) having a high Tg is contained, the sheet-like adhesive can maintain a predetermined shape until the completion of the curing reaction, and can fix the object at the target position.

The photo cation polymerization initiator is a compound that generates a cation species by irradiation with ultraviolet rays to initiate a curing reaction of a cation curable compound, and includes a cation portion that absorbs ultraviolet rays and an anion portion that is a generation source of an acid.

Examples of the photo cation polymerization initiator include: sulfonium salt compounds, iodonium salt compounds, phosphonium salt compounds, ammonium salt compounds, antimonate compounds, diazonium salt compounds, selenium salt compounds, oxonium salt compounds, bromine salt compounds, and the like. Among these, from the viewpoint of excellent compatibility with other components, sulfonium salt compounds are preferred, and aromatic sulfonium salt compounds having an aromatic group are more preferred.

Examples of the sulfonium salt compound include: triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4' -bis [ diphenylsulfonium]Diphenyl sulfide-bis (hexafluorophosphate), 4' -bis [ di (b) ((b))β-hydroxyethoxy) phenylsulfonium]Diphenyl sulfide-bis hexafluoroantimonate, 7- [ di (p-toluene)Formyl) sulfonium]-2-isopropylthioxanthone hexafluorophosphate, 7- [ di (p-toluoyl) sulfonium salt]-2-isopropylthioxanthone hexafluoroantimonate, 7- [ di (p-toluoyl) sulfonium]-2-isopropyltetrakis (pentafluorophenyl) borate, phenylcarbonyl-4 ' -diphenylsulfonium-diphenylsulfide-hexafluorophosphate, phenylcarbonyl-4 ' -diphenylsulfonium-diphenylsulfide-hexafluoroantimonate, 4-tert-butylphenylcarbonyl-4 ' -diphenylsulfonium-diphenylsulfide-hexafluorophosphate, 4-tert-butylphenylcarbonyl-4 ' -diphenylsulfonium-diphenylsulfide-hexafluoroantimonate, 4-tert-butylphenylcarbonyl-4 ' -diphenylsulfonium-diphenylsulfide-tetrakis (pentafluorophenyl) borate, 4- (phenylthio) phenyldiphenylsulfonium hexafluoroantimonate, 4- (phenylthio) phenyldiphenylsulfonium hexafluorophosphate, 4- {4- (2-chlorobenzoyl) phenylthio } phenylbis (4-fluorophenyl) diphenylsulfonium hexafluoroantimonate Acid salts, halides of phenylthiodiphenylsulfonium hexafluoroantimonate, 4 ', 4 ' ' -tris (R)β-hydroxyethoxyphenyl) sulfonium hexafluoroantimonate, 4' -bis [ diphenylsulfonium]Diphenyl sulfide-bis hexafluoroantimonate, diphenyl [4- (phenylthio) phenyl]Sulfonium trifluoro-tris (pentafluoroethyl) phosphate, tris [4- (4-acetylphenylsulfanyl) phenyl]Sulfonium tris [ (trifluoromethyl) sulfonyl group]And salts of methane compounds and phosphorus-based anions having 4- (phenylthio) phenyldiphenylsulfonium as the cation part and fluorine and perfluoroalkyl groups added as the anion part.

Examples of the iodonium salt-based compound include: diphenyliodonium tetrakis (pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, bis (4-nonylphenyl) iodonium hexafluorophosphate, (triisopropylphenyl) iodonium tetrakis (pentafluorophenyl) borate, and the like.

Examples of the phosphonium salt compound include: tri-n-butyl (2, 5-dihydroxyphenyl) phosphonium bromide, hexadecyltributylphosphonium chloride, and the like.

Examples of the ammonium salt compound include: benzyltrimethylammonium chloride, phenyltributylammonium chloride, benzyltrimethylammonium bromide, and the like.

Examples of the antimonate-based compound include: triphenylsulfonium hexafluoroantimonate, p- (phenylthio) phenyldiphenylsulfonium hexafluoroantimonate, 4-chlorophenyldiphenylsulfonium hexafluoroantimonate, bis [4- (diphenylsulfonium) phenyl ] sulfide bis hexafluoroantimonate, diallyliodilium hexafluoroantimonate, and the like.

These photo cation polymerization initiators may be used alone in 1 kind, or in combination with 2 or more kinds.

Further, as the photo cation polymerization initiator, commercially available products can be used. Examples of commercially available products include: cyracure UVI-6970, Cyracure UVI-6974, Cyracure UVI-6990, Cyracure UVI-950 (manufactured by Union Carbide Co., Ltd.), Irgacure 250, Irgacure 261, Irgacure 264 (manufactured by Ciba Specialty Chemicals Co., Ltd.), SP-150, SP-151, SP-170, OPTOMER SP-171 (manufactured by ADEKA Co., Ltd.), CG-24-61 (manufactured by Ciba Specialty Chemicals Co., Ltd.), DAICAT II (manufactured by Dal Co., Ltd.), UV159AC 0, UVAC1591 (manufactured by Dalel Cy206tec Co., Ltd.), CI-4, CI-2639, CI-2624, CI-2481, CI-2734, CI-2855, CI-2823, CI-2758, CIT-272 (manufactured by Japan PI-1684 (manufactured by Japan), Coco., BBI-2074 (manufactured by Roffi corporation), Roffi-2073C (manufactured by Roffi 102-207M Co., Ltd.), and so, BBI-101, BBI-103, MPI-103, TPS-103, MDS-103, DTS-103, NAT-103, NDS-103 (manufactured by Midori chemical Co., Ltd., above), CD-1010, CD-1011, CD-1012 (manufactured by Sartomer Co., Ltd.), CPI-100P, CPI-101A, CPI-200K, CPI-310B (manufactured by San-Apro Co., Ltd., above), San-Aid SI-60, San-Aid SI-80, San-Aid SI-100, San-Aid SI-110, San-Aid SI-150 (manufactured by Sanxin chemical industries, Ltd., above), and the like.

The content of the photo cation polymerization initiator is usually 0.1 to 10 parts by mass, preferably 0.3 to 8 parts by mass, and more preferably 0.5 to 6 parts by mass, relative to 100 parts by mass of the component (B).

[ (D) component ]

The sheet-like adhesive of the present invention preferably contains a silane coupling agent having a long-chain spacer (hereinafter, sometimes referred to as "silane coupling agent (D)") as the component (D).

The cured product of the sheet-like adhesive containing the silane coupling agent (D) is more excellent in adhesive strength.

The silane coupling agent is a silane compound having a silicon atom, a functional group, and a hydrolyzable group bonded to the silicon atom.

The long-chain spacer refers to a 2-valent group connecting a silicon atom and a functional group, and is a group in which the number of atoms constituting the main chain is 3 or more.

The number of atoms constituting the main chain is preferably 3 to 12, more preferably 6 to 10.

Examples of the long-chain spacer include: polymethylene groups such as trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, dodecamethylene, and the like.

The functional group means a group having reactivity with other compounds (mainly organic compounds).

As the functional group, there may be mentioned: vinyl group, allyl group, epoxy group, glycidyloxy group, 3, 4-epoxycyclohexyl group, amino group, substituted amino group, acryloyl group, methacryloyl group, mercapto group, isocyanate group, group having an acid anhydride structure, and the like.

Among these, from the viewpoint of easily obtaining a cured product excellent in shape retention under high-temperature conditions, a group having a cyclic ether structure such as an epoxy group, a glycidyloxy group, or a 3, 4-epoxycyclohexyl group is preferable as the functional group.

Examples of the "hydrolyzable group" include: alkoxy groups such as methoxy and ethoxy; halogen atoms such as chlorine atom and bromine atom.

Examples of the silane coupling agent (D) include: a compound represented by the following formula.

[ chemical formula 1]

R¹Represents a functional group, R²Represents an alkyl group having 1 to 5 carbon atoms. Plural R²May be the same or different from each other. x represents an integer of 6 or more.

As R¹The functional group of (2) includes: the functional group mentioned above. As R²The alkyl group having 1 to 5 carbon atoms includes: methyl, ethyl, and the like.

x is an integer of 3 or more, preferably an integer of 3 to 12, and more preferably an integer of 6 to 10.

Specific examples of the silane coupling agent (D) include: 8-glycidoxyoctyltrimethoxysilane, 8-glycidoxyoctyltriethoxysilane, 8-acryloyloxyoctyltrimethoxysilane, 8-acryloyloxyoctyltriethoxysilane, 8-methacryloyloxyoctyltrimethoxysilane, 8-methacryloyloxyoctyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, and the like.

The silane coupling agent (D) may be used alone in 1 kind, or in combination with 2 or more kinds.

When the sheet adhesive contains the silane coupling agent (D), the content of the silane coupling agent (D) is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 3 parts by mass, per 100 parts by mass of the component (B).

[ other ingredients ]

The sheet adhesive of the present invention may contain other components within a range not to impair the effects of the present invention.

As other components, there may be mentioned: additives other than the silane coupling agent (D), such as silane coupling agents, ultraviolet absorbers, antistatic agents, light stabilizers, antioxidants, resin stabilizers, fillers, pigments, extenders, and softeners.

These can be used alone in 1 kind, or in combination of 2 or more.

When the sheet adhesive of the present invention contains these additives, the content thereof may be determined as appropriate according to the purpose.

[ sheet adhesive ]

The thickness of the sheet adhesive of the present invention is usually 1 to 50μm is preferably 2 to 40μm, more preferably 5 to 30μAnd m is selected. A sheet-like adhesive having a thickness within the above range is suitably used as the material for forming the sealing material.

The thickness of the sheet-like adhesive can be measured by using a known thickness meter in accordance with JIS K7130 (1999). When the sheet-like adhesive has a release film described later, the thickness of the sheet-like adhesive is the thickness after the release film is removed.

The sheet-like adhesive of the present invention preferably has a release film on at least one side and may have release films on both sides, from the viewpoint of protecting the sheet-like adhesive from the external environment.

The sheet-like adhesive of the present invention having a release film on at least one surface thereof is used before use, and when the sheet-like adhesive of the present invention is used, the release film is usually peeled off and removed. When the sheet-like adhesive has release films on both surfaces, the release film having a low release force is usually removed by peeling first.

As the release film, a resin film is generally available.

As the resin component of the resin film, there can be mentioned: polyimide, polyamide, polyamideimide, polyphenylene oxide, polyether ketone, polyether ether ketone, polyolefin, polyester, polycarbonate, polysulfone, polyether sulfone, polyphenylene sulfide, polyarylate, acrylic resin, cycloolefin polymer, aromatic polymer, polyurethane polymer, and the like. Among these, polyester resins are preferred.

When the release film has a release agent layer, examples of the release agent include: silicone resins, olefin resins, isoprene resins, butadiene resins, and other rubber elastomers, long-chain alkyl resins, alkyd resins, fluorine resins, and the like.

The thickness of the release film is usually 10 to 300μm is preferably 10 to 200μm, more preferably 15 to 100μm。

The method for producing the sheet-like adhesive of the present invention is not particularly limited. For example, the resin composition can be produced by a casting method.

The sheet-like adhesive is produced by a casting method in which an adhesive composition is applied to a release film by a known method and the resulting coating film is dried to obtain a sheet-like adhesive with a release film.

The adhesive composition can be prepared by mixing and stirring the above-mentioned component (a), component (B), and component (C), and other necessary components by a known method.

When a solvent is used for preparing the adhesive composition, the viscosity of the adhesive composition can be appropriately adjusted by the amount of the solvent used.

Examples of the solvent include: aliphatic hydrocarbon solvents such as n-hexane and n-heptane; aromatic hydrocarbon solvents such as toluene and xylene; halogenated hydrocarbon solvents such as dichloromethane, vinyl chloride, chloroform, carbon tetrachloride, 1, 2-dichloroethane, and monochlorobenzene;

alcohol solvents such as methanol, ethanol, propanol, butanol, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; cellosolve solvents such as ethyl cellosolve; ether solvents such as 1, 3-dioxolane, and the like.

These solvents may be used alone in 1 kind, or in combination of 2 or more kinds.

The content of the solvent may be determined as appropriate in consideration of coatability, film thickness, and the like.

The release film for producing the sheet-like adhesive functions as a support in the production process of the sheet-like adhesive and functions as a release film for the sheet-like adhesive until the sheet-like adhesive is used.

Examples of the method for applying the adhesive composition include: spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, and the like.

Examples of the method for drying the coating film of the adhesive composition include: conventionally known drying methods such as hot air drying, hot roll drying, and infrared ray irradiation.

The conditions for drying the coating film are, for example, 80 to 150 ℃ for 30 seconds to 5 minutes.

The sheet adhesive of the present invention can be cured by irradiation with ultraviolet rays.

Specific examples of the ultraviolet source include: light sources such as ultrahigh-pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, carbon arc lamps, black light fluorescent lamps, and metal halide lamps. The wavelength of the ultraviolet light to be irradiated may be in the range of 190 to 380 nm.

The type, dose, and time of irradiation of the ultraviolet rays can be determined appropriately according to the components of the sheet adhesive to be irradiated, the contents of the components, and the like.

The preferred irradiation illumination intensity is 20-1000 mW/cm²The light amount is preferably 50 to 3000mJ/cm²Left and right.

The cured product of the sheet adhesive of the present invention has a storage modulus at 80 ℃ of preferably 500MPa or more, more preferably 800 to 3000MPa, and still more preferably 1200 to 2500 MPa.

A cured product having a storage modulus at 80 ℃ of 500MPa or more is less likely to deform even under high temperature conditions. Therefore, such a cured product can be preferably used as a sealing material whose performance hardly deteriorates even under high-temperature conditions.

The storage modulus at 80 ℃ of the cured product can be measured by the method described in examples.

The sheet-like adhesive of the present invention is suitable as a material for forming a sealing material for electronic devices because of the above-mentioned properties.

As the electronic device, there may be mentioned: various elements constituting the sealing body of the electronic device described later. As the various elements, there may be mentioned: an organic EL element, a liquid crystal element, an electronic paper element (electronic paper element), and the like.

2) Sealing sheet

The sealing sheet of the present invention comprises an adhesive layer comprising the sheet adhesive of the present invention and a functional film.

As the functional film, there may be mentioned: conductive films, gas barrier films, antireflection films, retardation films, viewing angle improving films, brightness improving films, and the like. Among these, examples of the gas barrier film include: a film having a metal film or an inorganic compound film, and the like, and a film having a metal film is preferable. Examples of the metal used include: aluminum, zinc, copper, and the like, and among these, aluminum is preferred.

The thickness of the functional film used in the present invention is not particularly limited, and is usually 5 to 200μm is preferably 10 to 100μm。

When the functional film is a film having a metal film or an inorganic compound film, the functional film may not easily transmit (transmit) violetThe outer line. Such a functional film generally has a transmittance of ultraviolet rays at a wavelength of 365nm of 60% or less. When the functional film is a film which is not easily permeable to ultraviolet rays, (a) production method described laterβ) The advantage of (2) becomes remarkable. From such a viewpoint, the production method (A) is usedβ) When the functional film is used for producing a sealing body for an electronic device, the functional film preferably has a transmittance of 55% or less, more preferably 50% or less, for ultraviolet rays having a wavelength of 365 nm.

The sealing sheet of the present invention may be any sealing sheet having at least the functional film and the adhesive layer comprising the sheet-like adhesive of the present invention.

The functional film may be 1 layer or 2 or more layers. The adhesive layer may be 1 layer or 2 or more layers.

In the case where the functional film is a gas barrier film having a metal film or an inorganic compound film and a resin film, an adhesive layer is provided on the side closer to the metal film or the inorganic compound film than the resin film in order to prevent water vapor entering from the end of the resin film from moving to a sealed device, and the adhesive layer and the resin film are preferably separated by the metal film or the inorganic compound film.

The sealing sheets of the invention may further have other layers.

As other layers, there may be mentioned: a primer layer for improving the adhesiveness at the interface between the adhesive layer and the functional film, a functional coating or protective film provided on one surface of the functional film not having the adhesive layer, an antistatic layer or a stress relaxation layer which can be formed on both surfaces of the functional film, and the like.

The thickness of the sealing sheet of the present invention is usually 6 to 270μAnd m is selected. The thickness of the sealing sheet is a thickness other than a member to be peeled and removed before use, such as a peeling film or a protective film.

The sealing sheet of the present invention can be produced by, for example, bonding the sheet-like adhesive of the present invention and a functional film.

3) Sealing body for electronic device

The sealing body for an electronic device of the present invention is formed by sealing an electronic device with an adhesive cured layer which is a cured product of the sheet-like adhesive of the present invention.

The electronic device may be the above-mentioned one.

The adhesive cured layer is a layer formed by curing the sheet-like adhesive of the present invention. The cured adhesive layer may be a layer formed by curing the adhesive layer of the sealing sheet of the present invention.

The cured product of the sheet-like adhesive of the present invention is easily a cured product excellent in colorless transparency. Since this characteristic is utilized, the sealing body of the electronic device is preferably an optical device such as a light emitting device, a light receiving device, or a display device.

As the light-dependent device, there can be mentioned: organic EL displays, organic EL lighting, liquid crystal displays, electronic paper, and the like. The sealing body of the electronic device is more preferably a display device such as an organic EL display, a liquid crystal display, and electronic paper.

The electronic device sealing body can be produced by the following production method having the steps (a1) to (a2) (a1)α) Or a production method having steps (b1) to (b2) (b1)β) To manufacture.

[ production method: (α)]

Step (a 1): a step of attaching the sheet-like adhesive of the present invention or the adhesive layer of the sealing sheet of the present invention to an electronic component to produce a laminate;

step (a 2): and (d) irradiating the sheet-like adhesive or the adhesive layer in the laminate obtained in the step (a1) with ultraviolet light.

The production method (α) The method is a method of initiating a curing reaction of a sheet-like adhesive after the sheet-like adhesive is attached to an electronic device.

After the curing reaction initiated by the process (a2) is completed, a known process is performed, whereby a sealing body of a target electronic device can be manufactured.

The production method (α) It is preferably used for efficiently manufacturing a sealing body of an electronic device.

[ production method: (β)]

Step (b 1): a step of irradiating the sheet-like adhesive of the present invention or the adhesive layer of the sealing sheet of the present invention with ultraviolet rays to initiate a curing reaction;

step (b 2): and (c) a step of attaching the sheet-like adhesive or the adhesive layer after the step (b1) to the electronic component before the completion of the curing reaction.

The production method (β) The method is a method of attaching a sheet-like adhesive to an electronic device after a curing reaction of the sheet-like adhesive is initiated and before the curing reaction is completed.

A known process is performed after the process (b2) and after the curing reaction initiated by the process (b1) is completed, whereby the sealing body of the objective electronic device can be manufactured.

The sheet-like adhesive of the present invention is an adhesive in which a curing reaction is initiated by a photo cation polymerization initiator, and a certain time is required until the curing reaction is completed. Thus, it can be manufactured by the method of (β) To manufacture an encapsulation for an electronic device.

The production method (β) The sealing sheet is preferably used when the electronic device may be broken by ultraviolet irradiation or when a layer having ultraviolet shielding properties is present as a layer such as a functional film, the layer being located outside the adhesive layer (on the side away from the electronic device to which the sealing sheet is attached).

Examples

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[ Compounds used in examples or comparative examples ]

Seeds and phenoxy resins (a 1): (trade name: YX7200B35, manufactured by Mitsubishi chemical corporation, glass transition temperature: 150 ℃ C.);

seeds and phenoxy resins (a 2): (trade name: YX6954BH30, manufactured by Mitsubishi chemical corporation, glass transition temperature: 130 ℃);

seed phenoxy resin (X): (trade name: 4250, manufactured by Mitsubishi chemical corporation, glass transition temperature: 78 ℃);

seeding liquid polyfunctional epoxy resin (BL 1): hydrogenated bisphenol a epoxy resin [ product name: YX8000, epoxy equivalent: 205g/eq ];

seeding liquid polyfunctional epoxy resin (BL 2): 3 ', 4' -epoxycyclohexylmethyl 3, 4-epoxycyclohexanecarboxylate [ product name: celloxide 2021P, epoxy equivalent: 128-145 g/eq ];

seeding photo cation polymerization initiator (C1): 4- (phenylthio) phenyldiphenylsulfonium hexafluorophosphate [ product name: CPI-100P ];

seeding photo cation polymerization initiator (C2): a salt of a phosphorus anion having a cation portion of 4- (phenylthio) phenyldiphenylsulfonium and an anion portion of a fluorine and a perfluoroalkyl group added thereto [ San-Apro, trade name: CPI-200K ];

seeding of silane coupling agent (D1): 8-glycidyloxyoctyltrimethoxysilane (trade name: KBM4803, manufactured by shin-Etsu chemical Co., Ltd.).

[ example 1]

100 parts by mass (in terms of active ingredients other than solvent, the same applies hereinafter) of the phenoxy resin (A1), 170 parts by mass of the liquid polyfunctional epoxy resin (BL1), 5 parts by mass of the photocationic polymerization initiator (C1) and 0.1 part by mass of the silane coupling agent (D1) were diluted with methyl ethyl ketone to prepare a resin composition (1) having an active ingredient concentration of 50%.

The resin composition (1) was applied to a release-treated surface of a release film (trade name: SP-PET752150, manufactured by LINTEC Co., Ltd.), and the resulting coating film was dried at 100 ℃ for 2 minutes to give a film having a thickness of 20μm is a sheet adhesive. A release-treated surface of another 1 sheet of release film (trade name: SP-PET381031, manufactured by LINTEC) was bonded to the sheet-form adhesive to prepare a release-film-attached sheet-form adhesive (1).

[ example 2]

A sheet-like adhesive (2) with a release film was produced in the same manner as in example 1, except that 120 parts by mass of a liquid polyfunctional epoxy resin (BL2) was used instead of the liquid polyfunctional epoxy resin (BL1) in example 1.

[ example 3]

A sheet-like adhesive (3) with a release film was produced in the same manner as in example 1, except that 3 parts by mass of a cationic photopolymerization initiator (C2) was used instead of the cationic photopolymerization initiator (C1) in example 1.

[ example 4]

A sheet-like adhesive (4) with a release film was produced in the same manner as in example 1, except that 100 parts by mass of the phenoxy resin (a2) was used instead of the phenoxy resin (a1) in example 1.

[ example 5]

A sheet-like adhesive (5) with a release film was produced in the same manner as in example 1, except that the content of the liquid polyfunctional epoxy resin (BL1) was changed to 100 parts by mass in example 1.

Comparative example 1

A sheet-like adhesive (6) with a release film was produced in the same manner as in example 1, except that 100 parts by mass of the phenoxy resin (X) was used instead of the phenoxy resin (a1) in example 1.

The following tests were carried out on the sheet-like adhesives (1) to (6) with release films obtained in examples 1 to 5 and comparative example 1. The results are shown in Table 1.

(evaluation of adhesion of sheet adhesive)

The sheet-like adhesive obtained in examples or comparative examples was laminated on glass at 23 ℃ and a pressure of 0.2MPa using a laminator.

By visual observation, the case where no peeling portion was generated was evaluated as "o", and the case where at least a part of peeling portion was generated was evaluated as "x".

(storage modulus of cured product of sheet-like adhesive)

The sheet-like adhesives obtained in examples and comparative examples were laminated at 23 ℃ and a pressure of 0.2MPa using a laminator to obtain a sheet having a thickness of 200Aμm, or a mixture thereof. Using a high pressure mercury lamp manufactured by Eye Graphics, a lamp with an illuminance of 200mW/cm was used²And a cumulative light amount of 2000mJ/cm²The laminate was irradiated with ultraviolet rays under the conditions of (1). The photometer used "UVPF-A1" manufactured by Eye Graphics. Thereafter, the laminate was heated at 100 ℃ for 2 hours to accelerate the reaction.

Using the laminate after the curing reaction as a sample, a storage modulus measuring apparatus (product name: DMAQ800, manufactured by TA Instrument Co.) was used in a tensile modeAt a frequency of 1Hz and an amplitude of 5μm, the storage modulus was measured. The temperature was increased at 3 ℃/min, and the measurement was carried out at-20 to 150 ℃. The results of the measurement at 80 ℃ are shown in Table 1.

[ Table 1]

The following is evident from table 1.

The cured products of the sheet-like adhesives (1) to (5) obtained in examples 1 to 5 were excellent in shape retention under high-temperature conditions.

As can be seen from comparative examples 1 to 5 and comparative example 1: the glass transition temperature of phenoxy resins has an effect on the shape retention of cured products under high temperature conditions.

Further, it can be seen by comparing examples 1 to 4 with example 5 that: by containing a large amount of the liquid polyfunctional epoxy resin (BL), both the adhesiveness of the sheet adhesive and the shape retention of the cured product under high temperature conditions are improved.