JP2001279218A - Photosetting adhesive composition and photosetting adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosetting adhesive composition exhibiting pressure- sensitive adhesivity at normal temperature, curable with light and giving a cured material having excellent bond strength and heat-resistant adhesivity even to an adherend having high polarity and prepare a photosetting adhesive sheet. SOLUTION: The photosetting adhesive composition contains a resin composed mainly of a polyester, a photo-cationic polymerizable compound and a photo- cationic polymerization initiator. The photo-cationic polymerizable compound is a compound giving a homopolymer having a dynamic storage elastic modulus of 103-1010 Pa at 25 deg.C and 10 Hz or having a glass transition temperature of <=150 deg.C. Preferably, the photo-cationic polymerizable compound is a resin containing at least one kind of structure selected from aliphatic polyether, aliphatic polyester, aliphatic polycarbonate, polyalkadiene and dimmer acid derivative skeleton in the molecule. The photosetting adhesive sheet is composed of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable pressure-sensitive adhesive composition which normally has pressure-sensitive adhesive properties and can be cured by irradiating light, and a sheet thereof.

[0002]

2. Description of the Related Art Conventionally, a pressure-sensitive adhesive, which can be easily attached to an adherend at the time of joining, is cured by some method after joining, and exhibits a curing type adhesive exhibiting the same adhesive strength as an adhesive. Agent compositions are known.

In recent years, as described in Japanese Patent Application Laid-Open No. 10-508636, such an adhesive composition has been coated on an adherend (in some cases, before it is coated on an adherend). (2) Photocurable pressure-sensitive adhesive compositions that are polymerized and cured by irradiation with light have been studied. The photocurable pressure-sensitive adhesive composition described in this publication contains a free-radical polymerizable polymer, a cationic photopolymerizable compound, and a cationic photopolymerization initiator.

However, in this technique, when a typical acrylic resin is used as a free-radical polymerizable polymer, and when polyethylene terephthalate (PET), polyvinyl chloride (PVC), metal or the like is used as an adherend, There is a problem that the adhesive strength after curing to these adherends is insufficient, and the adhesion reliability when trying to adhere to these adherends is low. On the other hand, a composition containing a polyester resin, an epoxy resin as a cationic photopolymerizable compound, and a cationic photopolymerization initiator as a photocurable hot melt adhesive is also known (for example, Japanese Patent Application Laid-Open No.
306346).

[0005]

However, in order to improve the adhesiveness of the photocurable pressure-sensitive adhesive composition to PET, PVC, metal and the like, it is generally used for hot melt adhesives as described in the above-mentioned publication. It has been found that there are various problems when the above polyester resin is used. That is, according to the study of the present inventors, since the glass transition temperature and the softening temperature of the polyester resin are generally higher than that of the acrylic polymer used as the pressure-sensitive adhesive, mild conditions such as normal temperature and normal pressure are used. When laminated and cured below,
It is difficult to develop sufficient peel adhesion strength. In view of the above-mentioned problems of the conventional photocurable pressure-sensitive adhesive, the present invention exhibits pressure-sensitive adhesiveness at room temperature, and has excellent adhesive strength even when cured by light and cured to a highly polar adherend. An object of the present invention is to provide a photocurable pressure-sensitive adhesive composition and a photocurable pressure-sensitive adhesive sheet having good heat resistance and adhesiveness.

[0006]

In order to achieve the above-mentioned object, the present invention according to claim 1 is directed to a photo-polymer comprising a resin containing polyester as a main component, a photo-cationic polymerizable compound, and a photo-cationic polymerization initiator. A photocurable pressure-sensitive adhesive composition, wherein the photocationically polymerizable compound is a compound having a dynamic storage elastic modulus of 10 ³ to 10 ¹⁰ Pa at 25 ° C. and 10 Hz of a homopolymer. provide. The present invention according to claim 2 is a photocurable pressure-sensitive adhesive composition containing a resin containing polyester as a main component, a cationic photopolymerizable compound, and a cationic photopolymerization initiator, wherein the cationic photopolymerizable compound is: Provided is a photocurable pressure-sensitive adhesive composition which is a compound having a glass transition temperature of a homopolymer of 150 ° C. or lower.

According to a third aspect of the present invention, there is provided a photocurable pressure-sensitive adhesive composition comprising a resin having a polyester as a main component, a cationic photopolymerizable compound, and a cationic photopolymerization initiator. Provided is a photocurable pressure-sensitive adhesive composition in which the compound is a resin containing at least one structure of an aliphatic polyether, an aliphatic polyester, an aliphatic polycarbonate, a polyalkadiene, and a dimer acid derivative skeleton in a molecule. I do. The present invention according to claim 4 provides a photocurable pressure-sensitive adhesive sheet comprising the photocurable pressure-sensitive adhesive composition according to any one of claims 1 to 3. Hereinafter, the present invention will be described in more detail.

<Resin Having Polyester as Main Component> In the present invention, the structure of the resin having polyester as a main component is not particularly limited, and may be any of aliphatic, alicyclic and aromatic structures. It may contain the reaction product of a dicarboxylic acid (or its diester equivalent) and a diol. Dicarboxylic acid (or its diester equivalent)
Is a saturated fatty acid containing 4 to 12 carbon atoms (including unbranched, branched or 5- or 6-membered cyclic material) and / or 8 to 15 carbon atoms. It may be an aromatic acid containing carbon atoms. Examples of suitable fatty acids are succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecandioic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclopentane Dicarboxylic acid, 2-methylsuccinic acid, 2-
Methylpentanedioic acid, 3-methylhexanedioic acid, and the like. Suitable aromatic acids are terephthalic acid, isophthalic acid, phthalic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4
4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl thioether dicarboxylic acid, and 4,4'-
Diphenylamine dicarboxylic acid. In these dicarboxylic acids, preferably, the structure between the two carboxyl groups contains only carbon and hydrogen. Any mixture of the above dicarboxylic acids can be used.

Usually, an aliphatic dicarboxylic acid such as adipic acid or sebacic acid is copolymerized in order to increase the flexibility of the polyester resin. It is preferable not to use such an aliphatic dicarboxylic acid. The diols are branched, unbranched and cyclic aliphatic diols having 2 to 12 carbon atoms such as ethylene glycol, diethylene glycol, 1,2-propylene glycol,
3-propylene glycol, 1,3-butanediol,
1,4-butanediol, α-methylbutanediol,
α-dimethylbutanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 3-methylpentanediol, 1,6-hexanediol, 1,
8-octanediol, cyclobutane-1,3-di (2′-ethanol), 1,4-dihydroxycyclohexane, cyclohexane-1,4-dimethanol, 1,
10-decanediol, 1,12-dodecanediol,
Neopentyl glycol; and long-chain diols such as polyoxyalkylene glycol and polytetramethylene ether glycol having an alkylene group having 2 to 9 (preferably 2 to 4) carbon atoms. Any mixture of the above diols can be used.

In order to improve the flexibility of a resin containing polyester as a main component, a diol is preferably a straight-chain alcohol having a large number of carbon atoms. When it is necessary to improve the moist heat resistance of the present composition, the polyester-based resin used in the present invention may have a structure in which an ether bond is introduced in the molecule. One of the introduction methods is a method of polycondensing a polyether having a hydroxyl group at a terminal with a dicarboxylic acid or a diol. Examples of the polyether to be used include polytetramethylene ether glycol, polypropylene glycol, and polyethylene glycol. If it is necessary to improve the wet heat resistance of the present composition, it is better to use a more hydrophobic resin, so that polytetramethylene ether glycol is preferred. The resin containing polyester as a main component may be obtained by esterifying a carboxyl group of a carboxylic acid compound, or may be obtained by subjecting a portion of an ester bond to a transesterification reaction, and etherifying or hydroxylating a hydroxyl group of a hydroxyl group-containing compound. It may be an esterified product or a copolymerized polyether with an alkylene oxide.

The resin containing the above polyester as a main component is
They may be used alone or in combination of two or more. The resin containing polyester as a main component is obtained, for example, by polycondensing the above dicarboxylic acid and diol using an appropriate catalyst. Preferred number average molecular weight is 1
50,000 to 50,000. Further, those having a softening temperature of 40 ° C. or higher according to a ring and ball measurement method are preferred. When the softening temperature is lower than 40 ° C., the obtained photocurable pressure-sensitive adhesive composition tends to flow, and may not show a sheet shape. It may have crystallinity at room temperature,
It is not necessary to have crystallinity, but if it is desired to increase the pressure-sensitive adhesiveness at room temperature, a material having no crystallinity is preferable. When it is desired to promote curing at room temperature, the glass transition temperature of the resin containing polyester as a main component is preferably 25 ° C. or less. When it is desired to improve the wet heat resistance, the glass transition temperature of the resin containing polyester as a main component is preferably 25 ° C. or higher. Further, those which sufficiently transmit light effective for starting curing are preferable. Further, those having an acid value of 3 mgKOH / g or less are preferable. Acid value is 3
If it exceeds mgKOH / g, a reaction with the cationic photopolymerizable functional group occurs during storage of the present composition, whereby pressure-sensitive adhesiveness is not exhibited, curing does not proceed, and moisture-heat resistance is poor. May drop. In the present invention, the proportion of the polyester component in the resin containing polyester as a main component is 50% by weight or more.

<Cationic photopolymerizable compound> The photocationically polymerizable compound in the present invention comprises an organic compound having a photocationically polymerizable functional group capable of being increased in molecular weight by cationic polymerization.
It may be in any form such as a polymer, and its structure may be any structure such as aliphatic, alicyclic, and aromatic. Further, the photocationically polymerizable functional group may be present at any terminal in the molecular skeleton, in a side chain, or in the molecular skeleton. Examples of the photocationically polymerizable functional group include an epoxy group, an oxetane group, a vinyl ether group, an episulfide group, and an ethyleneimine group. The number of cationic photopolymerizable functional groups in the cationic photopolymerizable compound is preferably one or more per molecule, more preferably two or more per molecule. Here, the number of cationic photopolymerizable functional groups per molecule is determined by dividing the total number of cationic photopolymerizable functional groups in the cationic photopolymerizable compound by the total number of molecules in the cationic photopolymerizable compound.

The shape (properties) of the above cationic photopolymerizable compound may be any of liquid, semi-solid, and solid at room temperature, but it has a boiling point of 200 ° C. or higher and at room temperature. It is preferably liquid or semi-solid. The boiling point of the cationic photopolymerizable compound is 200 ° C
If it is less than 3, the photocationically polymerizable compound volatilizes from the obtained photocurable pressure-sensitive adhesive composition, and there is a possibility that the performance may decrease and the atmosphere may be polluted. When the photocationically polymerizable compound is solid at room temperature, the resulting photocurable pressure-sensitive adhesive composition may not exhibit pressure-sensitive adhesive properties at room temperature. Further, it may have crystallinity at room temperature or may not have crystallinity. However, when it is desired to enhance pressure-sensitive adhesiveness at room temperature, a material having no crystallinity is preferable. When it is desired to promote curing at room temperature, the glass transition temperature of the cationic photopolymerizable compound is preferably 25 ° C. or lower. Further, those which sufficiently transmit light effective for starting curing are preferable. In addition, a structure (amino group, etc.) that excessively suppresses the progress of cationic polymerization and makes the composition incompletely cured.
Are preferred. Further, as long as macro phase separation does not occur with other components constituting the present composition, it may be compatible with these or may be incompatible. Here, the macro phase separation refers to a state in which any or all of the components are completely separated in a transparent state, and is different from a state in which the components are merely clouded by micro phase separation. .

The photocationically polymerizable compound is not particularly limited, and examples thereof include a cyclic ether compound such as an epoxy group-containing compound, an oxetane compound, and an oxolane compound, a cyclic ester compound, a vinyl ether compound, and the like. Propenyl ether compounds and the like are mentioned, and are preferably used. The above-mentioned cationic photopolymerizable compound may be used alone or in combination of two or more. Resin 10 containing the above polyester as a main component
The amount of the cationic photopolymerizable compound is preferably from 10 to 100 parts by weight based on 0 part by weight. If the amount of the cationic photopolymerizable compound exceeds 100 parts by weight, PET, PVC
This is because when the amount is less than 10 parts by weight, the proportion of a cross-linking component due to cationic polymerization decreases, and the heat resistance after curing may decrease. Among the various cationic photopolymerizable compounds, an epoxy group-containing compound is more preferably used. The epoxy group-containing compound refers to an organic compound having at least one oxirane ring that can be polymerized by cationic polymerization. The number of epoxy groups in the epoxy group-containing compound is preferably one or more per molecule, more preferably two or more per molecule. Where 1
The number of epoxy groups per molecule is determined by dividing the total number of epoxy groups in the epoxy group-containing compound by the total number of molecules in the epoxy group-containing compound.

The above-mentioned epoxy group-containing compound is not particularly limited. For example, bisphenol A
Novolak type epoxy resins such as bisphenol type epoxy resins such as type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, and trisphenol methane tri Aromatic epoxy resins such as glycidyl ether and the like, and hydrogenated and brominated products thereof; 3,4-epoxycyclohexylmethyl-3,4-
Epoxycyclohexanecarboxylate, 3,4-epoxy-2-methylcyclohexylmethyl 3,4-epoxy-2-methylcyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) adipate, bis (3,4-epoxycyclohexylmethyl) Adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexanone-meta-dioxane, bis (2 3-epoxycyclopentyl) ether, trade name "EHPE-31
Alicyclic epoxy resins such as "50" (softening temperature: 71C, manufactured by Daicel Chemical Industries, Ltd.); diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl of glycerin Ether, triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol,
Such as polyglycidyl ether of polypropylene glycol, polyoxyalkylene glycol having an alkylene group having 2 to 9 (preferably 2 to 4) carbon atoms, and polyglycidyl ether of a long-chain polyol including polytetramethylene ether glycol. Aliphatic epoxy resins;
Diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl-p-oxybenzoic acid, glycidyl ether of salicylic acid-glycidyl ester,
Glycidyl ester type epoxy resins such as dimer acid glycidyl ester and the like and hydrogenated products thereof; triglycidyl isocyanurate, N, N of cyclic alkylene urea
Glycidylamine type epoxy resins such as N'-diglycidyl derivatives, N, N, O-triglycidyl derivatives of p-aminophenol, N, N, O-triglycidyl derivatives of m-aminophenol, and hydrogenated products thereof A copolymer of glycidyl (meth) acrylate and a radical polymerizable monomer such as ethylene, vinyl acetate, or (meth) acrylate; a polymer mainly composed of a conjugated diene compound such as epoxidized polybutadiene or the like; Epoxidized unsaturated carbon double bond of partially hydrogenated polymer; "Polymer block mainly composed of vinyl aromatic compound" such as epoxidized SBS and "conjugated diene compound mainly" Of a block copolymer having the same polymer block or a partially hydrogenated polymer block in the same molecule. Diene compound obtained by epoxidizing unsaturated carbon double bond; polyester resin having one or more (preferably two or more) epoxy groups per molecule; urethane bond or Polyurethane-modified epoxy resin or polycaprolactone-modified epoxy resin into which polycaprolactone bond is introduced; NBR, CTB
Various conventionally known epoxy group-containing compounds such as a rubber-modified epoxy resin containing a rubber component such as N, polybutadiene, and acrylic rubber; The epoxy group-containing compounds may be used alone or in combination of two or more.

The cationic photopolymerizable compound according to the present invention comprises
The dynamic storage elastic modulus at 25 ° C. and 10 Hz of the homopolymer is 10 ³ to 10 ¹⁰ Pa, preferably 10 ³ to 10 ⁹ P
a, more preferably a compound having a pressure of 10 ³ to 10 ⁸ Pa. Here, the homopolymer is, for example, 1 part by weight of the aromatic cationic sulfonium antimony hexafluoride, which is the cationic photopolymerization initiator, per 100 parts by weight of the cationic photopolymerizable compound.
365n using a super high pressure mercury lamp
After irradiating 3000 mJ / cm2 with light having a wavelength of m, 23 ° C
It was left at -65% RH (relative humidity) for 7 days.
The dynamic storage elastic modulus is measured according to JIS K7198, and has a frequency of 10 Hz and a heating rate of 3 ° C.
/ Min when measured by the method A (tensile vibration method)
Dynamic storage modulus in ° C. When the dynamic storage elastic modulus at 25 ° C. and 10 Hz exceeds 10 ¹⁰ Pa, the composition exhibits brittleness at room temperature after curing and does not exhibit sufficient adhesive strength. Also 10
^If it is less than ³ Pa, the heat resistance after curing may be insufficient. Further, the cationic photopolymerizable compound in the present invention, the glass transition temperature of the homopolymer is 150 ℃ or less,
Preferably, the compound has a temperature of 90 ° C. or lower, more preferably 25 ° C. or lower. Here, the glass transition temperature is frequency 1
JIS K7198 A at 0 Hz and 3 ° C./min.
The value (tan δ) obtained by dividing the dynamic loss elastic modulus by the dynamic storage elastic modulus when measuring by the method (tensile vibration method) is the temperature at which the maximum value is obtained. If the glass transition temperature is higher than 150 ° C., it will become brittle at room temperature after curing, and will not exhibit sufficient adhesive strength. The cationic photopolymerizable compound in the present invention,
By using a resin containing at least one structure of an aliphatic polyether, an aliphatic polyester, an aliphatic polycarbonate, a polyalkadiene and a dimer acid derivative skeleton in a molecule, the glass transition of a resin containing polyester as a main component is achieved. Even when the temperature is high, the brittleness after curing can be reduced and the adhesive strength can be sufficiently exhibited. Therefore, the resin containing the above structure includes a resin containing a saturated aliphatic skeleton and an unsaturated aliphatic skeleton.

The cationic photopolymerizable compound will be described in more detail. Examples of the aliphatic polyether include diglycidyl ether of bisphenol A ethylene oxide adduct, diglycidyl ether of bisphenol A propylene oxide adduct, and polyethylene glycol. And diglycidyl ether of polypropylene glycol. Examples of the aliphatic polyester include bisphenol A type epoxy resin-modified ε-caprolactone. Examples of the aliphatic polycarbonate include 1,6-hexanediol. Examples of the compound having a dimer acid derivative skeleton include diglycidyl ether of polycarbonate. Examples of the compound having a dimer acid derivative skeleton include dimer acid diglycidyl ester, and dimer acid and bisphenol A diglycidyl ester. It includes reaction products of ethers, examples of polyalkadienes alpha, the reaction product of ω-polybutadiene dicarboxylic acid and bisphenol A diglycidyl ether, but is not limited thereto.

<Photocationic polymerization initiator> The photocurable pressure-sensitive adhesive composition of the present invention contains a photocationic polymerization initiator as an essential component. The cationic photopolymerization initiator may be of an ionic photoacid generating type or of a nonionic photoacid generating type. The cationic photopolymerization initiator of the ionic photoacid generation type is not particularly limited, and examples thereof include onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts, and iron-allene complexes and titanocene complexes. And organometallic complexes such as arylsilanol-aluminum complex, etc., more preferably, aromatic iodonium salt, aromatic sulfonium salt, and metallocene salt, and still more preferably, aromatic sulfonium salt. One or more of these are suitably used. By containing these photocationic polymerization initiators, the photocurable pressure-sensitive adhesive composition can rapidly cure by irradiation with light having a wavelength of 200 to 400 nm, and the photocurable pressure-sensitive adhesive composition It becomes excellent in storage stability and the like when preserving the product.

The above-mentioned aromatic iodonium salt, aromatic sulfonium salt and metallocene salt effective as a photocationic polymerization initiator are described, for example, in US Pat. No. 4,256,828, US Pat. No. 5,089,536, and JP-A-6-3.
No. 06346. Among the above cationic photopolymerization initiators, aromatic iodonium salts and aromatic sulfonium salts do not generate cations in light outside the ultraviolet region, but are known sensitizers such as aromatic amines and colored aromatic polycyclic hydrocarbons. By using the agent in combination, cations can be generated even in the near ultraviolet region or the visible region. When a metallocene salt is used, a reaction accelerator such as an oxalate ester of tertiary alcohol may be used in combination. Specific examples of the ionic photoacid generating type cationic photopolymerization initiator are not particularly limited, and include, for example, trade names “ADEKA OPTOMER SP150” and “ADEKA OPTOMER SP170” (all manufactured by Asahi Denka Kogyo KK). And trade names "UVE-1014" (manufactured by General Electronics), trade names "CD-1012" (manufactured by Sartomer), and one or more of these are suitably used. The nonionic photoacid generator-type photocationic polymerization initiator is not particularly limited, and includes, for example, nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimide sulfonate. And one or more of these are preferably used.
The above cationic photopolymerization initiator may be used alone, or two or more kinds may be used in combination. The amount of the cationic photopolymerization initiator is not particularly limited, but is 0.1 to 10 parts by weight based on 100 parts by weight of the total amount of the resin containing the polyester as a main component and the cationic photopolymerizable compound. Is preferred. If the amount of the cationic photopolymerization initiator is less than 0.1 part by weight, the cationic photopolymerization may not proceed sufficiently or the curing may be too slow. Conversely, if the amount exceeds 10 parts by weight, the curing will be too fast,
It may be difficult to attach the adherends to each other.

In the present invention, light is used as the activation energy applied to activate the above cationic photopolymerization initiator. The light is not particularly limited, for example, microwave, infrared, visible light,
Ultraviolet rays, X-rays, γ-rays and the like can be mentioned, and ultraviolet rays which are particularly easy to handle and can obtain relatively high energy are more preferably used. Particularly preferably, ultraviolet light having a wavelength of 200 to 400 nm is used. Although the ultraviolet rays are not particularly limited, for example, carbon arc, mercury vapor arc, fluorescent lamp, argon glow lamp, halogen lamp, incandescent lamp, low-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, flash UV lamp, deep UV lamp Irradiation can be performed using an appropriate light source such as a xenon lamp, a tungsten filament lamp, and sunlight. Since the irradiation amount of the light varies depending on the type and amount of each component constituting the photocurable pressure-sensitive adhesive composition, the coating thickness, the light irradiation source, and the like, it cannot be uniquely determined. It is desirable that the irradiation amount at a wavelength effective for generating cations from the initiator is in the range of 0.01 to 100 J / cm ² .

<Other Components> The photocurable pressure-sensitive adhesive composition according to the present invention may contain, if necessary, an aliphatic hydroxyl group-containing compound for delaying curing, as long as the object of the present invention is not hindered. Thermoplastic resin, adhesion improver, filler, reinforcing material, softener, plasticizer, viscosity modifier, thixotropic agent, stabilizer, antioxidant, coloring agent, dehydrating agent,
One or more of various additives such as a flame retardant, an antistatic agent, a foaming agent, and a fungicide may be contained. The aliphatic hydroxyl group-containing compound may be in any form such as a monomer, an oligomer, and a polymer, and the aliphatic hydroxyl group may be present at a terminal of the molecular skeleton, a side chain, or any site in the molecular skeleton. You may. The number of the aliphatic hydroxyl groups is preferably one or more per molecule, more preferably two or more per molecule. Where 1
The number of aliphatic hydroxyl groups per molecule is determined by dividing the total number of aliphatic hydroxyl groups in the aliphatic hydroxyl group-containing compound by the total number of molecules in the aliphatic hydroxyl group-containing compound.

The aliphatic hydroxyl group-containing compound is not particularly restricted but includes, for example, polyhydroxyalkane, alkylene glycol and alkylene groups having 2 to 9 (preferably 2 to 4) carbon atoms. Long-chain polyols including polyoxyalkylene glycols and polytetramethylene ether glycols, hydroxyl-terminated polyalkadienes, hydroxyl-terminated polyesters not included in the resin containing the polyester of the present invention as a main component, hydroxyl-terminated polycaprolactone, hydroxyl-terminated polycarbonate, Acrylic polyols, (partial) saponified ethylene-vinyl acetate copolymers, polyvinyl alcohol, castor oil, ketone resins, xylene resins, and copolymers and modified products of these aliphatic hydroxyl group-containing compounds, and the like. Of 1
Species or two or more species are suitably used. The amount of the aliphatic hydroxyl group-containing compound is not particularly limited, but is an amount such that the ratio of the number of aliphatic hydroxyl groups to the number of photocationically polymerizable functional groups in the composition of the present invention is 10 or less. It is preferred that If the ratio of the number of the aliphatic hydroxyl groups to the number of the cationic photopolymerizable functional groups exceeds 10, the resulting photocurable pressure-sensitive adhesive composition may have insufficient heat resistance. The shape (properties) of the above-mentioned aliphatic hydroxyl group-containing compound may be any of liquid, semi-solid, and solid at room temperature, but it has a boiling point of 200 ° C. or higher and is liquid or semi-solid at room temperature. It is preferably solid. When the boiling point of the aliphatic hydroxyl group-containing compound is less than 200 ° C., the photocationically polymerizable compound volatilizes from the obtained photocurable pressure-sensitive adhesive composition, and there is a possibility that the performance is reduced and the atmosphere is polluted. If the aliphatic hydroxyl group-containing compound is solid at room temperature, the resulting photocurable pressure-sensitive adhesive composition may not exhibit pressure-sensitive adhesive properties at room temperature. When it is desired to accelerate the curing at room temperature, the aliphatic hydroxy group-containing compound preferably has a glass transition temperature of 25 ° C. or lower.

The thermoplastic resin is not particularly restricted but includes, for example, polyolefin resins such as ethylene-vinyl acetate copolymer; block polymers such as styrene-butadiene-styrene block copolymer; Coalescing; polycaprolactone resin; polycarbonate resin; tackifying resins such as rosin-based resins, terpene-based resins, styrene-based resins, petroleum-based resins, etc .; various commonly used thermoplastic resins such as waxes. One or two or more of these are suitably used. The above-mentioned adhesion improver is not particularly limited, and examples thereof include various conventionally known adhesion improvers such as a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. Species or two or more species are suitably used.

The filler is not particularly restricted but includes, for example, inorganic fillers such as calcium carbonate, magnesium carbonate, clay, talc, titanium oxide, asbestos, etc .; rayon, acrylic fiber, nylon fiber, glass fiber, carbon fiber Fibers such as cellulose, cellulose, etc .; hollow fillers, such as glass balloons, shirasu balloons, vinylidene chloride balloons, acrylic balloons, etc .; organic spheres, such as nylon beads, acrylic beads, silicon beads, etc .; urea melamine Conventionally known various fillers such as resin powder, acrylic resin powder, synthetic resin powder such as phenol resin powder, etc .; natural powder such as wood flour, fruit husk powder and the like and surface treated products thereof; One or more of these are preferably used.

The above-mentioned various components contained in the photocurable pressure-sensitive adhesive composition according to the present invention are compatible with the other components constituting the present composition unless they cause macrophase separation. And may be incompatible. Here, the macro phase separation refers to a state in which any or all of the components are completely separated in a transparent state, and is different from a state in which the components are merely clouded by micro phase separation. . The above-mentioned various components contained in the photocurable pressure-sensitive adhesive composition according to the present invention can cause a reaction with a photocationically polymerizable functional group during storage.
For example, it is preferable that the compound does not have a functional group such as an aromatic hydroxyl group and a (anhydrous) carboxyl group. Further, the above-mentioned various components are preferably those which do not decompose or volatilize during storage or irradiation with light, and are preferably those which can sufficiently transmit light necessary for the initiation of curing. Further, the various components may have crystallinity at room temperature or may not have crystallinity, but if it is desired to enhance pressure-sensitive adhesiveness at room temperature, it has crystallinity. Those that do not are preferred. Furthermore, the above-mentioned various components may not have a functional group such as an amino group, for example, which excessively suppresses the progress of cationic polymerization and inhibits curing of the photocurable pressure-sensitive adhesive composition. preferable.

<Parameters as Composition> The photocurable pressure-sensitive adhesive composition according to the present invention preferably has a glass transition temperature of 25 ° C. or lower when it is desired to promote curing at room temperature. If the glass transition temperature is higher than 25 ° C., curing tends to hardly proceed at room temperature, and sufficient adhesive strength tends not to be obtained. Further, the photocurable pressure-sensitive adhesive composition according to the present invention may be used at 25 ° C.
Dynamic storage elastic modulus at 10 Hz is 10 ³ to 10 ⁹ Pa
It is preferred that If it exceeds 10 ⁹ Pa, curing hardly proceeds at room temperature and sufficient adhesive strength cannot be obtained.
When the pressure is less than 10 ³ Pa, the photocurable pressure-sensitive adhesive composition tends to flow and may not show a sheet shape. The photocurable pressure-sensitive adhesive composition according to the present invention preferably has a cationically polymerizable group content of 0.01 to 10 mmol / g. If the amount is less than 0.01 mmol / g, the curing may not proceed sufficiently, and 10 mmol / g
If it exceeds 300, the curing proceeds before the adherends are bonded to each other, and a sufficient adhesive strength may not be obtained.

The photocurable pressure-sensitive adhesive composition of the present invention preferably has an absorbance of 0.001 to 0.2 for light having a wavelength of 350 nm per 100 μm thickness. 0.
If it is less than 001, curing may not proceed sufficiently, and if it exceeds 0.2, light may not be sufficiently spread to deep portions, and it may not be possible to cure uniformly. In addition, the photocurable pressure-sensitive adhesive composition of the present invention preferably has a pot life of 10 minutes or more from when the light is irradiated to when bonding becomes impossible. If the pot life is shorter than 10 minutes, the curing proceeds before the adherends are bonded to each other, so that sufficient adhesive strength may not be obtained.

Further, the photocurable pressure-sensitive adhesive composition of the present invention is characterized in that the cation-polymerizable functional group is left at 25 ° C. for 10 minutes after irradiating light to induce a ring-opening reaction of the photocationically-polymerizable functional group. The conversion is preferably 30% or less. If the conversion exceeds 30%, the curing proceeds before the adherends are pasted to each other, so that sufficient adhesive strength may not be obtained. Further, it is preferable that the conversion rate of the cationically polymerizable functional group after leaving to stand at 25 ° C. for 7 days after irradiating light to induce a ring opening reaction of the cationically polymerizable functional group is 50% or more.
If the conversion is less than 50%, curing will be insufficient and sufficient adhesive strength cannot be obtained. The photocurable pressure-sensitive adhesive composition of the present invention has a gel fraction of 10% or less after standing at 25 ° C. for 10 minutes after irradiating light to induce a ring-opening reaction of the photocationically polymerizable functional group. Is preferred. Gel fraction is 10%
If it exceeds 300, curing proceeds before the adherends are bonded to each other, and sufficient adhesive strength may not be obtained. Further, the gel fraction after standing at 25 ° C. for 7 days after irradiating light to induce a ring opening reaction of the cationic photopolymerizable functional group is preferably 30% or more. If the gel fraction is less than 30%, curing will be insufficient and sufficient adhesive strength cannot be obtained.

The photocurable pressure-sensitive adhesive composition of the present invention has a glass transition temperature of −20 to 20 after standing at 25 ° C. for 7 days after irradiating light to induce a ring-opening reaction of the photocationically polymerizable functional group. 3
Preferably it is 0 ° C. If the glass transition temperature is higher than 30 ° C., it will become brittle at room temperature after curing and will not exhibit sufficient adhesive strength. When the glass transition temperature is lower than −20 ° C., the wet heat resistance may be insufficient. Further, the photocurable pressure-sensitive adhesive composition of the present invention, after being irradiated with light to induce a ring-opening reaction of the photocationically polymerizable functional group, is left at 25 ° C. for 7 days,
Dynamic storage elastic modulus at 5 ° C. and 10 Hz is 10 ⁵ to 10
It is preferably ⁹ Pa. If more than 10 ⁹ Pa,
It shows brittleness at room temperature after curing and does not exhibit sufficient adhesive strength. On the other hand, if it is lower than 10 ⁵ Pa, the wet heat resistance may be insufficient.

<Production Method> The production method of the photocurable pressure-sensitive adhesive composition according to the present invention is not special after the components to be blended are prepared.
Using a mixer such as a universal mixer, a planetarium mixer, a kneader, or a three-roll, at room temperature or under heating,
By uniformly mixing a predetermined amount of each component to be blended, a desired photocurable pressure-sensitive adhesive composition can be obtained.
It is desirable that the above-described manufacturing be performed in a state where light is blocked. Kneading of each component at the time of production may be carried out without a solvent, for example, in an inert solvent such as aromatic hydrocarbon, acetate, ketone and the like.

In the above-mentioned production, if the water content of each component is large, the progress of curing after irradiating the obtained photocurable pressure-sensitive adhesive composition with light may be hindered. It is preferable to remove water in each component in advance. The method for removing water is not particularly limited, and examples thereof include a method of dehydration by mixing with a molecular sieve, a method of heating and dehydrating with an oven or a heater, and a method of dehydrating under reduced pressure. But
It is not limited to these methods. The kneading of each component may be usually performed under atmospheric pressure, but it is preferable to perform kneading under a reduced pressure atmosphere or an inert gas atmosphere such as a nitrogen gas when it is particularly desired to avoid mixing of water.

<Use of Photocurable Pressure-Sensitive Adhesive Composition> The photocurable pressure-sensitive adhesive composition of the present invention obtained as described above is applied as it is to one or both surfaces of a joining member (adherend). It is preferable to carry out photo-cation polymerization and cure. The timing of irradiating the photocurable pressure-sensitive adhesive composition with light, which is activation energy, may be before or after bonding with the joining member to which the photocurable pressure-sensitive adhesive composition is applied.
Further, in order to obtain better handling workability and simplicity, the photo-curable pressure-sensitive adhesive composition of the present invention is processed into a pressure-sensitive adhesive sheet in advance like the photo-curable pressure-sensitive adhesive sheet of the present invention to form a sheet. It is preferable to use them.

<Photocurable pressure-sensitive adhesive sheet> The photocurable pressure-sensitive adhesive sheet of the present invention comprises the photocurable pressure-sensitive adhesive composition according to any one of claims 1 to 3. Usually, it is used in a form in which a pressure-sensitive adhesive sheet comprising the photocurable pressure-sensitive adhesive composition of the present invention is laminated on both surfaces of a sheet-shaped support subjected to a release treatment (pressure-sensitive adhesive sheet laminate), In some cases, a form in which an adhesive sheet is laminated on only one surface of the support may be used. The support and the release sheet are not particularly limited, for example,
Polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polycarbonate, nylon, polyarylate, polysulfone, polyethersulfone, polyetheretherketone, polyphenylene sulfite, polystyrene, polyacryl,
Examples include polyvinyl acetate, triacetyl cellulose, diacetyl cellulose, cellophane and the like. The support and release sheet are not particularly limited, but preferably have a thickness of 10 μm or more. 10 μm thick
If it is less than 10, the strength is low, and the support or the release sheet may be torn during use.

The processing method for obtaining the above-mentioned pressure-sensitive adhesive sheet laminate is not particularly limited. For example, a bar coating method, a roll coating method, a gravure coating method, an extrusion coating method and the like are applied on a release-treated sheet-like support. The desired pressure-sensitive adhesive sheet laminate is obtained by coating the photocurable pressure-sensitive adhesive composition into a sheet by various coating methods such as a method and protecting the surface of the pressure-sensitive adhesive sheet with a release sheet such as polyethylene, for example, and winding it up. Method. In the above processing, the photocurable pressure-sensitive adhesive composition is solid, or semi-solid,
If the coating is difficult due to high viscosity even in a liquid state, the viscosity may be reduced by, for example, diluting with an organic solvent or melting by heating. The coating thickness of the pressure-sensitive adhesive sheet obtained in this manner is not particularly limited, but the thickness of itself is 1 to 3.
It is preferably 2000 μm, more preferably 1 μm.
0 to 1000 μm. The thickness of the adhesive sheet itself is 1μ
When the thickness is less than m, the unevenness of the surface of the joining member may adversely affect the adhesiveness of the pressure-sensitive adhesive sheet. On the contrary, when the thickness of the pressure-sensitive adhesive sheet itself exceeds 2000 μm, the curing time may be excessively long.

<Joining Method> In the method of joining an adherend using the photocurable pressure-sensitive adhesive composition or photocurable pressure-sensitive adhesive sheet of the present invention, for example, activation energy is imparted to the photocurable pressure-sensitive adhesive composition. The timing may be either before or after the joining between the adherend to which the photocurable pressure-sensitive adhesive composition is applied and the joining member. For example, when at least one of the joining members is light-transmitting, after applying or attaching a photocurable pressure-sensitive adhesive composition or a photocurable pressure-sensitive adhesive sheet to at least one joining member, the other joining member and Joined,
By irradiating light from the surface of the light-transmissive bonding member, activation energy may be applied to photo-cationically polymerize and cure the photo-curable pressure-sensitive adhesive composition or photo-curable pressure-sensitive adhesive sheet. In the case of this method, it is desirable to apply activation energy as soon as possible after the joining members are joined in order to reduce the time of the entire joining process. In addition, at the time of joining, in order to improve the adhesion, it is possible to heat and join with the joining member.

When both joining members are not light-transmitting, a photo-curable pressure-sensitive adhesive composition or a light-post-curable pressure-sensitive adhesive sheet is applied or affixed to at least one of the joining members. After applying activation energy by irradiating the pressure-sensitive adhesive sheet surface with light, it is bonded to the other bonding member, and the photocurable pressure-sensitive adhesive composition or the photocurable pressure-sensitive adhesive sheet is photocationically polymerized and may be cured. .
In the case of this method, in order to smoothly join the one joining member and the other joining member, after the activation energy is applied, the joining members are joined as quickly as possible, preferably within 10 minutes. It is desirable to carry out. In this case, the light irradiation method may be, for example, directly irradiating the photocurable pressure-sensitive adhesive composition, or indirectly irradiating the photocurable pressure-sensitive adhesive composition through a transparent or translucent adherend or a protective film. Irradiation may be carried out. In any of the above methods, the curing of the photocurable pressure-sensitive adhesive composition or the photocurable pressure-sensitive adhesive sheet by the photocationic polymerization reaction proceeds in a short time at room temperature, and the cured product exhibits excellent adhesive strength and heat-resistant adhesiveness. I do. Further, in order to further promote the curing reaction of the photocurable pressure-sensitive adhesive composition or the photocurable pressure-sensitive adhesive sheet and further shorten the curing time, simultaneously with or after the application of the activation energy by the light irradiation, heating. Other curing means such as those described above may be used in combination.

In bonding, pressurization is performed at an appropriate pressure for a necessary time using a press, a laminator, or the like. At this time, the photocurable pressure-sensitive adhesive composition may be completely cured by heating sufficiently during pressurization using a hot press, a heat laminator, or the like. The adherend (joined body) to which the photocurable pressure-sensitive adhesive composition or the photocurable pressure-sensitive adhesive sheet according to the present invention is applied,
There is no particular limitation, for example, iron, aluminum, copper, lead,
Tin, zinc, nickel, magnesium, titanium, gold, silver,
Extensive materials such as metals or alloys such as platinum or their painted bodies, various plastics or plastic mixtures, inorganic materials such as glass, concrete, stone, mortar, ceramics and ceramics, cellulosic materials such as wood and paper, and leather. Including. In addition, the above-mentioned various adherends may be adhered with the same material adherend or with different material adherends. The shape of the adherend is a plate, a lump,
Any shape such as a rod, a sheet, a string, a fiber, a honeycomb, a tube, and a particle may be used.Also, adherends having the same shape may be bonded, or adherends having different shapes may be bonded. Is also good.

(Function) The photocurable pressure-sensitive adhesive composition according to the present invention contains a resin containing polyester as a main component, a photocationic polymerizable compound and a photocationic polymerization initiator, and the photocationic polymerizable compound is a single polymer. Since the compound is a compound having a dynamic storage modulus of 10 ³ to 10 ¹⁰ Pa at 25 ° C. and 10 Hz or a compound having a glass transition temperature of a homopolymer of 150 ° C. or less, the cationic polymerization is performed by light irradiation. Curing proceeds, after curing, due to the synergistic effect of the resin containing polyester as a main component and the cationic photopolymerizable compound,
It exhibits excellent adhesive strength and good heat-resistant adhesion to adherends with high polarity. When the photocationically polymerizable compound is a resin containing a specific structure in the molecule, it is ensured that excellent adhesive strength is exhibited. Since the photocurable pressure-sensitive adhesive sheet according to the present invention is composed of the above-mentioned photocurable pressure-sensitive adhesive composition, in addition to the above-described effects, good handling workability and workability at the time of joining are excellent.

[0039]

Example (Example 1)

<Polyester used> As polyester, 25 mol% of terephthalic acid, 25 mol% of isophthalic acid, ethylene glycol, neopentyl glycol 1
A polyester obtained by copolymerizing 7.5 mol%, 17.5 mol% of an ethylene glycol adduct of bisphenol A, and 25 mol% of polytetramethylene ether glycol was used.

<Epoxy Resin Used> As an epoxy resin as a photocationically polymerizable compound, Bisphenol A diglycidyl ether “Epicoat 828” (manufactured by Yuka Shell Epoxy) was used.

<Photocationic Polymerization Initiator Used> As the photocationic polymerization initiator, "ADEKA OPTOMER SP170" (manufactured by Asahi Denka Kogyo KK), which is an aromatic sulfonium antimony hexafluoride salt, was used.

<Preparation of Epoxy Resin Homopolymer> 100 parts by weight of the epoxy resin “Epicoat 828” and the above-mentioned photocationic polymerization initiator “Adeka Optomer SP170” 1
Parts by weight with a homodisper-type stirring mixer (trade name: “Homodisper L”, manufactured by Tokushu Kika Co., Ltd.) at a stirring speed of 3000 rpm to prepare a photocurable epoxy resin composition. did. A 5 mm × 50 mm strip-shaped hole was formed in a 1 mm thick Teflon (registered trademark) sheet, placed on a 50 μm thick PET film subjected to a release treatment, and the above prepared photocurable epoxy resin composition was prepared. And irradiated with ultraviolet rays having a wavelength of 365 nm using an ultra-high pressure mercury lamp so that the irradiation amount becomes 3000 mJ / cm ^2, and then cured by leaving it in a dark place at 23 ° C.-65% RH for 7 days, and cured by 5 mm × 50 mm × A 1 mm strip-shaped epoxy resin homopolymer was obtained.

<Measurement of Dynamic Storage Elastic Modulus and Glass Transition Temperature at 10 ° C. at 25 ° C.> Using a dynamic viscoelasticity measuring apparatus VES-F3 manufactured by Iwamoto Seisakusho, at a frequency of 10 Hz and a heating rate of 3 ° C./min. The dynamic storage elastic modulus and the dynamic loss elastic modulus were measured in accordance with JIS K7198 method A (tensile vibration method), and the dynamic storage elastic modulus at 25 ° C. was determined. The temperature at which the value (tan δ) obtained by dividing the dynamic loss elastic modulus by the dynamic storage elastic modulus shows the maximum value was determined as the glass transition temperature.

<Preparation of Sample> Polyester: 80 parts by weight of the prepared polyester Epoxy resin: 20 parts by weight of Epicoat 828 Photocationic polymerization initiator: 1 part by weight of Adeka Optomer SP170 Solvent: 150 parts by weight of methyl ethyl ketone

<Preparation of Photocurable Pressure-Sensitive Adhesive Sheet> The above composition was stirred using a homodisper type stirring mixer (trade name “Homodisper L”, manufactured by Tokushu Kika Co., Ltd.) at a stirring speed of 3000.
The mixture was uniformly stirred and mixed at a rpm to prepare a polyester-based photocurable pressure-sensitive adhesive composition. A 50 μm-thick PET film subjected to a mold release treatment was used as a support, and was coated using a bar coater so as to have a thickness of 100 μm after coating, followed by drying to form a photocurable pressure-sensitive adhesive sheet. Next, a release-treated surface of a PET film that had been subjected to silicone release treatment as a protective film was laminated on the surface of the pressure-sensitive adhesive composition of the obtained photocurable pressure-sensitive adhesive sheet, to produce a photocurable pressure-sensitive adhesive sheet laminate.

<Preparation of Bonded Body> A photocurable pressure-sensitive adhesive sheet was laminated at room temperature on a corona-treated surface of a corona-treated PET film while peeling off the protective film of the photocurable pressure-sensitive adhesive sheet laminate. Next, the release PET film is peeled off, and the pressure-sensitive adhesive composition surface of the photocurable pressure-sensitive adhesive sheet is irradiated with ultraviolet light having a wavelength of 365 nm using an ultrahigh pressure mercury lamp so that the irradiation amount becomes 2400 mJ / cm ^2, and immediately thereafter, PE with corona treatment applied to the surface of the adhesive composition
It was laminated at room temperature on the corona treated surface of the T film.
This was placed in a gear oven at 110 ° C. for 30 minutes to cure.

<Evaluation of Adhesive Strength> The above joined body was cut into a width of 10 mm, and a T-type peeling test was performed at a peeling speed of 50 mm / min using a Tensilon type tensile tester. The results are shown in Table 1. <Evaluation of heat resistance> The joined body was cut to a width of 25 mm,
One PET film was hung on a top plate of a gear oven with a 200 g weight attached thereto, and subjected to a shearing type temperature rising creep test at a temperature rising rate of 5 ° C./min to measure the breaking temperature. The results are shown in Table 1.

(Example 2) As a epoxy resin, "Rikaresin BPO-20E" which is a diglycidyl ether of bisphenol A propylene oxide 2 mol adduct (manufactured by Shin Nippon Rika Co., Ltd., having an aliphatic polyether structure)
A sample was prepared and evaluated in the same manner as in Example 1, except that was used. The results are shown in Table 1.

Example 3 As an epoxy resin, a reaction product of dimer acid and bisphenol A diglycidyl ether, "YD-172" (manufactured by Toto Kasei Co., Ltd., having a dimer acid derivative skeleton structure) was used. Other than using it,
A sample was prepared and evaluated in the same manner as in Example 1.
The results are shown in Table 1.

(Example 4) As epoxy resins, α, ω
Example 1 Example 1 was repeated except that "NISSO Epoxy EPB-13" (manufactured by Nippon Soda Co., Ltd., containing the structure of polyalkadiene), which was a reaction product of polybutadiene dicarboxylic acid and bisphenol A diglycidyl ether, was used.
A sample was prepared and evaluated in the same manner as described above. The results are shown in Table 1.

(Comparative Example) The epoxy resin used was o-
"YDCN" which is a cresol novolak type epoxy resin
A sample was prepared and evaluated in the same manner as in Example 1 except that "-704" (manufactured by Toto Kasei) was used. The results are shown in Table 1.

[0053]

[Table 1]

[0054]

The photocurable pressure-sensitive adhesive composition of the present invention is constituted as described above, exhibits pressure-sensitive adhesive properties at room temperature, is cured by light irradiation, and has a high polarity after curing. And also exhibits excellent adhesive strength and good heat resistance. In addition, the photocurable pressure-sensitive adhesive sheet of the present invention is composed of the above-mentioned photocurable pressure-sensitive adhesive composition, and in addition to the above-mentioned effects, has good workability and workability during joining.

Continued on the front page F term (reference) 4J004 AA13 AA14 AA15 AB01 AB07 4J040 EC002 EC092 EC312 EC412 ED001 JB08 JB09 KA13 LA02

Claims (4)

[Claims] 1. A photocurable pressure-sensitive adhesive composition comprising a resin containing polyester as a main component, a cationic photopolymerizable compound, and a cationic photopolymerization initiator, wherein the cationic photopolymerizable compound is a homopolymer. A photocurable pressure-sensitive adhesive composition, which is a compound having a dynamic storage modulus of 10 ³ to 10 ¹⁰ Pa at 25 ° C. and 10 Hz. 2. A photocurable pressure-sensitive adhesive composition comprising a resin containing a polyester as a main component, a photocationically polymerizable compound, and a photocationic polymerization initiator, wherein the photocationically polymerizable compound is a homopolymer. A photocurable pressure-sensitive adhesive composition, which is a compound having a glass transition temperature of 150 ° C. or lower. 3. A photocurable pressure-sensitive adhesive composition comprising a resin containing a polyester as a main component, a photocationically polymerizable compound, and a photocationic polymerization initiator, wherein the photocationically polymerizable compound has one or more A photocurable pressure-sensitive adhesive composition, which is a resin containing at least one structure of an aliphatic polyether, an aliphatic polyester, an aliphatic polycarbonate, a polyalkadiene, and a dimer acid derivative skeleton. 4. A photocurable pressure-sensitive adhesive sheet comprising the photocurable pressure-sensitive adhesive composition according to claim 1.