JP2000144071A - Photopolymerizable composition, photocurable adhesive sheet and method for joining members - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photopolymerizable composition which transmits light to a deep part when irradiated to effect sure curing to the deep part by compounding a photopolymerizable compound, a resin particulate, a polymer compatible with the resin particulate and a photopolymerization initiator. SOLUTION: This photopolymerizable composition comprises 100 pts.wt. of a photopolymerizable compound (A), 1-30 pts.wt. of a particulate (B) such as of a styrene resin or the like having an average particle size of 0.01-30 μm and a haze value per 100 μm thickness of 20% or less, 0-1,000 pts.wt. of a polymer (C) compatible with the resin particulate and 0.1-10 pts.wt. of a cationic photopolymerization initiator (D) such as an iron-arene complex or the like. As the component A is employed a cationic photopolymerizable compound such as an epoxy resin, e.g. bisphenol A type, phenol novolak type or the like, or the like. As the component C is employed a polymer which is compatible with the component A before the photopolymerization and causes phase separation of the component A with the progress of the curing after the irradiation of light, such as acrylic, silicone, polyurethane-, polyester-, polyether- polymers or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photopolymerizable composition,
More specifically, for example, a photocurable photopolymerizable composition suitably used as a pressure-sensitive adhesive or a pressure-sensitive adhesive sheet, and the photopolymerizable composition The present invention relates to a photocurable adhesive sheet and a method for joining members using the same.

[0002]

2. Description of the Related Art Conventionally, acrylic pressure-sensitive adhesives are excellent in heat resistance, weather resistance, oil resistance, etc., and are also excellent in adhesive properties such as adhesive strength and cohesive strength. Widely used for adhesive processed products such as. However, the above-mentioned pressure-sensitive adhesive processed product is designed to be soft in order to develop a pressure-sensitive adhesive force (pressure-sensitive adhesive force). Therefore, although it is excellent in workability, it cannot exhibit excellent adhesive properties such as a high peeling force and a shearing force like an adhesive. Therefore, applications requiring high bonding reliability, such as bonding in the electrical and electronic fields,
It could not be widely used for applications such as bonding of houses or building components.

On the other hand, epoxy adhesives are widely used as adhesives that exhibit excellent adhesive strength. However, since epoxy adhesives are generally liquid at room temperature, the thickness of the coating may be uneven at the time of application, the appearance of the bonding end may be reduced due to the protrusion of the adhesive, or fixed with a jig until curing is completed. Had to be kept. That is, since it is a liquid, the bonding operation has to be complicated.

[0004] Further, a method is known in which a carboxyl-terminal liquid NBR (CTBN) is added to an epoxy resin to exhibit high shear strength and peel strength. in this way,
After the epoxy resin and CTBN are once dissolved and the curing agent is mixed, the NBR phase is separated as the curing proceeds. Therefore, by forming a sea-island structure in which NBR domains are formed in the epoxy matrix, the epoxy resin is toughened.

However, since the phases are separated during the curing, the dispersion state of the NBR domains and the size of the NBR phase tend to change depending on the type of the curing agent and the curing conditions, and the physical properties are not stable. Further, since the low molecular elastomer component remains in the matrix resin even after curing, there is a problem that the glass transition point is lowered. Therefore, although the stress relaxation property is enhanced and the peel strength is enhanced, there is a problem that the shear strength and the heat resistance are reduced.

Accordingly, a method has been proposed in which a crosslinked NBR is added to an epoxy resin. In this method, crosslinked NBR in the form of particles is dispersed in an uncured epoxy resin in advance, and the domain size of the NBR phase is constant regardless of curing conditions. Therefore, it can be expected to exhibit stable physical properties. In addition, it has a crosslinked structure in advance,
Because the low molecular component is small, the lowering of the glass transition point of the cured product is less than in the case of using low molecular liquid NBR,
It can exhibit physical properties excellent in balance between shear strength and peel strength.

[0007] However, crosslinking NBR to epoxy resin
In the case where is added, if the compatibility with the epoxy resin is poor, there is a problem that the cross-linked NBR particles aggregate and the epoxy resin becomes cloudy, and the micro-phase separation occurs between the epoxy resin and the cross-linked NBR. . in this case,
In order to cure the adhesive composition by light, there has been a problem that long-time light irradiation is required, and it is not possible to sufficiently cure a deep part.

Japanese Patent Application Laid-Open No. Sho 60-173076 proposes a method of forming an epoxy resin-based adhesive into a sheet or film. However, since the adhesive sheet obtained by this method is generally solid at room temperature, it has low initial adhesive strength and does not have temporary fixing properties. Therefore, workability at the time of joining was not sufficient. Also, since the sheet-like epoxy resin adhesive does not have sufficient adhesion to the adherend, harsh conditions such as a high-temperature press or a high-pressure press are required when laminating the adherends. It could not be applied to adherends that were not resistant to the conditions.

On the other hand, JP-A-2-272076 discloses a photopolymerizable monomer syrup containing an acrylate ester as a main component, an epoxy resin having no photopolymerizable group,
A pressure-sensitive thermosetting adhesive and sheet each containing a specific amount of an epoxy resin-based thermosetting agent, a photoinitiator and a photocrosslinking agent are disclosed.

However, the pressure-sensitive thermosetting adhesive sheet described in the prior art requires heating to cure the epoxy resin, and is used for bonding an adherend having poor heat resistance such as plastic. Could not.

Further, Japanese Patent Publication No. 5-506465 discloses a pressure-sensitive adhesive containing a radical photopolymerization component such as an acrylate monomer, a cationic polymerization component such as an epoxy compound, and an organometallic complex salt initiator. A composition is disclosed. This pressure-sensitive adhesive composition has been proposed to increase the strength of the adhesive, and is irradiated with ultraviolet light in the step of producing the pressure-sensitive adhesive to polymerize both the radical polymerization component and the photocationic polymerization component. I have. Therefore, the polymerization reaction is already completed when the pressure-sensitive adhesive is formed into a sheet, for example, and is configured to have sufficient strength in advance. However, since the polymerization reaction has been completed, the curing reaction no longer proceeds after the adherends are bonded, and it is not possible to improve the adhesive strength more than at the time of bonding.

Japanese Patent Application Laid-Open No. 10-120994 discloses an adhesive composition containing an adhesive polymer such as an acrylic polymer, an epoxy group-containing resin, and a compound that induces a ring-opening reaction of an epoxy group. The haze value of the pressure-sensitive adhesive sheet is 15% or less, and it can be used as a pressure-sensitive adhesive sheet in a normal state. Proposed.

[0013] In this curable adhesive sheet, before the light irradiation, the adhesive tape has the simplicity of work, and after the light irradiation and bonding, curing proceeds by a dark reaction, and high adhesive properties are exhibited. . However, the haze value before curing is 15% or less, the adhesive polymer and the resin having an epoxy group are compatible, and after the curing, the adhesive polymer and the resin having an epoxy group are compatible, Haze value does not change. Therefore, since the cohesive force is developed by the compatibility between the cured adhesive polymer and the resin having an epoxy group after curing, the stress relaxation property of the cured product is not sufficient, and the adhesive strength is further improved. Although improvement is desired, it has been difficult to meet this demand.

[0014]

SUMMARY OF THE INVENTION In view of the above-mentioned state of the art, an object of the present invention is to exhibit good tackiness (pressure-sensitive adhesiveness) in an initial state and to be cured by irradiation with light. Further, a photopolymerizable composition which is more excellent in the stress relaxation property and adhesive strength of the cured product, and which can surely reach light to a deep part upon irradiation of light, and which can be surely cured to a deep part, It is an object of the present invention to provide a photocurable pressure-sensitive adhesive sheet and a method for joining members using a conductive composition.

[0015]

The photopolymerizable composition according to the first aspect of the present invention comprises: A: a photopolymerizable compound, and B: a photopolymerizable compound A before irradiation with light, It is characterized by comprising resin fine particles which undergo curing and undergo phase separation with the photopolymerizable compound A after light irradiation, C: a polymer having compatibility with the resin fine particles B, and D: a photopolymerization initiator. .

According to the second aspect of the present invention, J
The haze value according to IS K7105 is less than 20% per 100 μm thickness, and after irradiation with light and curing progresses, the haze value is 20 to 100% per 100 μm thickness.
Range.

According to a third aspect of the present invention, the polymer C
Contains a functional group that reacts with the photopolymerizable compound A after light irradiation. In the invention described in claim 4, as the polymer C, a polymer C obtained by subjecting a photopolymerizable composition containing a radical polymerizable monomer or oligomer to photoradical polymerization is used.

According to a fifth aspect of the present invention, there is provided a photocurable pressure-sensitive adhesive sheet formed using each of the photopolymerizable compositions according to the first to fourth aspects. The method for bonding members according to the invention according to claim 6 is a method for bonding a member to a photocurable adhesive sheet before or after bonding the members to each other via the photocurable adhesive sheet according to claim 5. It is characterized by irradiation with light and curing.

Hereinafter, the present invention will be described in detail. (Photopolymerizable compound) The photopolymerizable compound used in the present invention may be any of a photocationic polymerizable compound, a photoradical polymerizable compound and a photoanionic polymerizable compound, and two or more of these may be used in combination. May be.

In particular, since the curing reaction proceeds by a dark reaction after light irradiation, a photocationically polymerizable compound is preferably used. The photocationically polymerizable compound is not particularly limited, but various compounds mainly having a cyclic ether such as a vinyl ether group, an episulfide group, an ethyleneimine group, and / or an epoxy group are used. The molecular weight of the photocationically polymerizable compound is not particularly limited, and a polymer may be used as the photocationically polymerizable compound in some cases.

As the photocationically polymerizable compound, an epoxy group-containing compound is preferably used. Since ring-opening polymerization of an epoxy group has high reactivity and a short curing time, the bonding step can be shortened. Moreover, since the epoxy group-containing compound is excellent in cohesive force and elastic modulus, it is possible to obtain an adhesive cured product excellent in heat resistance and adhesive strength. Therefore, for example, when the present invention is applied to a printed circuit board or a flexible printed board, it is possible to effectively prevent adhesion abnormality such as peeling or displacement in a step of exposure to high heat such as soldering in these manufacturing steps.

As the epoxy group-containing compound, an epoxy resin is preferably used. Examples of the epoxy resin include a suitable epoxy resin such as a bisphenol A type, a bisphenol F type, a phenol novolak type, a cresol novolak type, a glycidyl ether type, and a glycidylamine type.

The epoxy group-containing compound may be an epoxy group-containing oligomer.
Examples of the epoxy group-containing oligomer include a bisphenol A type epoxy oligomer (for example, Epicoat 1001, 1002, manufactured by Yuka Shell Epoxy Co., Ltd.).

Further, as the epoxy group-containing compound, an addition polymer of the epoxy group-containing monomer or oligomer may be used, and examples thereof include glycidylated polyester, glycidylated polyurethane, and glycidylated acryl.

In particular, an acrylic polymer such as glycidylated acryl having an epoxy group has a high compatibility with the acrylic adhesive polymer when an acrylic adhesive polymer is used as the polymer C described later. In such cases, it is preferably used. Acrylic polymers such as glycidylated acryl containing epoxy groups are known as O
It can be obtained by reacting epichlorohydrin with an acrylic polymer having an H group, or by copolymerizing glycidyl (meth) acrylate.

The photopolymerizable compound may be modified with a different kind of resin, if necessary, or may be modified with a functional group. It may have a functional group.
Furthermore, in the above-mentioned cationic photopolymerizable compound, other resin components may be blended or added to enhance flexibility, and to improve adhesion and bending force.

Examples of the modified cationic photopolymerizable compound include CTBN (butadiene acrylonitrile rubber containing a terminal carboxyl group) modified epoxy resin; various rubbers such as acrylic rubber, NBR, SBR, butyl rubber, nitrile rubber and isoprene rubber. An epoxy resin to which a base resin is added; a chelate-modified epoxy resin; a polyol-modified epoxy resin, and the like can be used, and these fine particles may be added.

In consideration of the compatibility with the resin fine particles B, an epoxy resin excellent in compatibility with the resin fine particles B and capable of finely dispersing the resin fine particles B,
Poor compatibility with epoxy resin, when the resin fine particles are added to it alone, a method of using together with an epoxy resin that causes the resin fine particles to agglomerate, and further, excellent compatibility with the resin fine particles B in an uncured state An epoxy resin capable of finely dispersing resin fine particles, wherein after the curing, the compatibility with the resin fine particles B deteriorates due to a change in polarity, and the epoxy resin in which the resin fine particles are phase-separated to form an aggregate is used. It is preferably used.

Here, the compatibility means that the fine resin particles B are finely dispersed and the average particle diameter of the fine resin particles is 0.01 to 30 μm.
m, preferably 0.01 to 10 μm, and refers to a state in which the haze value per 100 μm thickness of the photopolymerizable composition is 20% or less.

In the present invention, when a photo-cationic polymerizable compound is used as the photo-polymerizable compound A, the equivalent of the cationic polymerizable functional group contained in the photo-polymerizable composition is:
Preferably it is 5000 g-resin / mol or less. If the equivalent of the cationically polymerizable functional group is too large, the concentration of the functional group in the composition decreases, the cationic polymerization becomes insufficient, and the adhesive strength decreases. Therefore, it is desirable to determine the composition so that the equivalent of the cationically polymerizable functional group falls within the above range.

(Resin Fine Particles B) In the present invention, as the resin fine particles B, the photopolymerizable compound A before light irradiation is used.
It is possible to use a resin made of an appropriate resin that is compatible with the compound and that undergoes curing after light irradiation and undergoes phase separation with the photopolymerizable compound A. Preferably, as the resin fine particles B,
Before the light irradiation, the haze value of the entire photopolymerizable composition is 1
When the curing after light irradiation is completed, the haze value of the entire composition is preferably in the range of 20% to 100%, preferably less than 20% per 100 μm, more preferably 10% or less, and still more preferably 1% or less. .

Examples of the resin fine particles include those generally used as tackifying resins such as styrene resins, petroleum resins and natural resins; polyolefins such as polyethylene; rubber resins such as polybutadiene;
Fine particles composed of various resins such as polyester, polyurethane, polyether, polycarbonate, and polyvinyl chloride can be used, and one kind thereof may be used or two or more kinds may be used in combination.

Preferably, rubber-based resin fine particles such as acrylic rubber, NBR or SBR are used in order to increase the stress relaxation of the cured adhesive. Further, a functional group may be introduced on the surface of the resin fine particles in order to adjust the compatibility with the photopolymerizable compound A. Examples of such a functional group include polar groups such as a carboxyl group, a hydroxyl group, and an epoxy group. And non-polar groups constituted by modifying these functional groups with non-polar groups.

The particle diameter of the resin fine particles B in the photopolymerizable composition to which the resin fine particles B are added is preferably 0.01 to 30 μm, as described above.
More preferably, it is in the range of 0.01 to 10 μm.

(Polymer C) The polymer C used in the present invention is compatible with the resin fine particles B. Here, “has compatibility with the resin fine particles B” means that even if the resin fine particles B are dispersed or agglomerated as primary particles in the polymer, the composition is formed into a sheet having a thickness of 100 μm. Haze value is 2
It means that the particle size is not more than 0%.
At this time, the particle diameter of the agglomerated resin fine particles is set to 0.1.
The range is preferably from 01 to 30 μm, more preferably from 0.1 to 30 μm.
The range is from 01 to 30 μm.

The polymer C is not particularly limited as long as it has the above compatibility, and may be a general rubber, acrylic, silicone, polyurethane, polyester, or the like.
Various polyether-based polymers can be used. In particular, an acrylic polymer is preferably used because it alone has tackiness.

The acrylic adhesive polymer is a (co) polymer containing alkyl (meth) acrylate as a main component, and the alkyl group includes a methyl group, an ethyl group,
-Butyl group, i-butyl group, hexyl group, octyl group,
i-octyl, 2-ethylhexyl, nonyl and the like are preferred.

In the acrylic pressure-sensitive adhesive polymer, a vinyl monomer may be copolymerized with the alkyl (meth) acrylate, if necessary. Examples of such a vinyl monomer include (meth) acrylic acid and maleic acid. Acid components such as acrylonitrile, urethane acrylate, styrene, vinyl acetate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate,
ε- (poly) caprolactone acrylate, tetrahydrofuranyl acrylate, and the like.

If the glass transition point Tg of the polymer C is too high, the pressure-sensitive adhesive property is reduced and it becomes difficult to perform pressure bonding at room temperature. Therefore, the glass transition point Tg is desirably 20 ° C. or lower.

When using acrylic rubber fine particles as the resin fine particles B, it is preferable to use an acrylic polymer as the polymer C in order to enhance the above-mentioned compatibility.

The polymer C desirably contains a functional group that reacts with the photopolymerizable compound A after light irradiation. Examples of such a functional group include a reactive functional group such as a cyclic ether group such as a carboxyl group, a hydroxyl group, and an epoxy group. The method for introducing the functional group may be introduced by copolymerizing the functional group-containing monomer by copolymerization when polymerizing the polymer C, or may be introduced after synthesizing the polymer C. . When an epoxy resin is used as the photopolymerizable compound A, the functional group introduced into the polymer C is preferably an epoxy group or a hydroxyl group, in order to enhance the stability during storage. preferable.

Further, as described in claim 4, the polymer C may be obtained by photoradical polymerization of a photopolymerizable composition containing a radical polymerizable monomer or oligomer. In this case, since the radical polymerization reaction is inhibited by oxygen in the air and oxygen dissolved in the photopolymerizable composition, it is preferable to perform light irradiation under conditions that can eliminate the inhibition of the oxygen reaction. Although there is no particular limitation on such a method, for example, a method in which a photopolymerizable composition is coated with a polyethylene terephthalate (PET) film, a fluoroethylene resin film, or the like, and light is irradiated through the film, A method in which polymerization is performed by light irradiation in an atmosphere replaced with a gas may be used.

As the polymerization initiator used in the photoradical polymerization, it is desirable to use a polymerization initiator activated by light having a longer wavelength than the photosensitive wavelength of the cationic photopolymerization initiator. In this case, the type of the photo-radical polymerization initiator is not particularly limited, and one or more conventional photo-radical polymerization initiators can be used.

(Photopolymerization Initiator D) In the present invention, the photopolymerization initiator D is appropriately selected according to the type of the photopolymerizable compound A. That is, when a photocationic polymerizable compound is used as the photopolymerizable compound A, a photocationic polymerization initiator is used, and when a photoradical polymerizable compound is used, a photoradical polymerization initiator is used.

Above all, as described above, a photo-cationic polymerizable compound is suitably used as the photo-polymerizable compound A because curing proceeds by a dark reaction after light irradiation. In this case, a photo-polymerization initiator is used. As D, the following cationic photopolymerization catalyst is used.

That is, examples of the above cationic photopolymerization catalyst include iron-allene complex compounds, aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, and the like.
A pyridinium salt, an aluminum complex-silyl ether, or the like can be used, and is not particularly limited.

Further, as a specific example of the above-mentioned cationic photopolymerization catalyst, Asahi Denka Kogyo KK, trade name: Optomer SP
-170, Optmer SP-171, manufactured by Ciba-Geigy Corporation, trade name: Irgacure 261 and the like.

(Blending ratio) The blending ratio of each component in the photopolymerizable composition according to the first aspect of the present invention is as follows.
Although not particularly limited, the photopolymerizable compound A10
1 to 30 parts by weight of the resin fine particles B, 10 to 1,000 parts by weight of the polymer C, and 0.1 to 0.1 parts by weight of the photopolymerization initiator D based on 0 parts by weight.
It is desirable that the content be in the range of 1 to 10 parts by weight.

When the mixing ratio of the resin fine particles B is less than 1 part by weight, the effect of improving the adhesive strength may be small, and
When the amount is more than the weight part, the adhesive layer after curing may become weak due to aggregation of particles.

When the amount of the polymer C is less than 10 parts by weight, the particles may not be uniformly dispersed. When the amount exceeds 1000 parts by weight, the adhesive strength after curing may be low. When the compounding ratio of the photopolymerization initiator D is less than 0.1 part by weight, the composition may not be sufficiently cured. Conversely, when the composition exceeds 10 parts by weight, the composition is irradiated with light and cured before bonding. Sometimes.

(Photo-Curing Adhesive) The photo-polymerizable composition according to the first to fourth aspects of the present invention is obtained by mixing the above-mentioned essential components, and is used as a photo-curing adhesive. It can be suitably used.

(Photocurable Adhesive Sheet) The photopolymerizable composition according to the first to fourth aspects of the present invention is formed into a sheet to form a photocurable adhesive sheet. The use of such a photo-curable adhesive sheet is preferable because the amount of the photo-curable composition to be applied during the joining operation and the adjustment of the coating film pressure can be easily performed.

The method for forming the sheet is not particularly limited, and any known method such as hot melt coating or cast coating of the photopolymerizable composition according to claims 1 to 4 can be used. Can be used.

(Joining Method) When joining adherends using the photocurable adhesive sheet according to the present invention, light is applied before or after attaching the photocurable adhesive sheet to the adherend. After irradiation and activation of the photopolymerization initiator D, the adherends are preferably attached to each other. The irradiation amount of light to be applied to the photopolymerization initiator D is desirably at least 50 mJ / cm ² or more in the case of light having a wavelength of 300 to less than 370 nm. 50mJ /
When it is less than cm ² , it may be difficult to sufficiently activate the photopolymerization initiator D.

As a light source for exposing the photopolymerizable composition according to the present invention, for example, an excimer laser, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, microwave excitation Examples include a mercury lamp, a metal halide lamp, a fluorescent lamp, and natural light such as sunlight.

(Other Addable Components) In the photopolymerizable composition and the photocurable pressure-sensitive adhesive sheet according to the present invention, in addition to the above-mentioned essential components, a range not to impair the object of the present invention is provided.
Known surfactants, tackifier resins, extenders, sensitizers, and the like may be appropriately blended.

Before curing, it is desirable to further add a surfactant in order to stably disperse the resin fine particles B in the photopolymerizable composition. By the addition of the surfactant, the resin fine particles B are stably finely dispersed before curing, the haze value is reduced, and the stability at the time of storing the photopolymerizable composition is increased.

The surfactant is not particularly limited as long as it does not hinder the object of the present invention and can finely disperse the resin fine particles B in the photopolymerizable composition before curing. An agent, a cationic surfactant or a nonionic surfactant is appropriately used.

As the tackifying resin, rosin resin, modified rosin resin, terpene resin, terpene phenol resin, aromatic modified terpene resin, C5 or C9
A petroleum-based resin, a coumarone resin, or the like may be added.
In particular, when the adherend is a polyolefin, a rosin-based resin or a petroleum-based resin is preferably used because strong adhesion can be exhibited.

In order to enhance coatability, thickeners such as acrylic rubber, epichlorohydrin rubber, isoprene rubber, and butyl rubber; thixotropic agents such as colloidal silica and polyvinylpyrrolidone; extenders such as calcium carbonate, titanium oxide and clay ; Polyester, (meta)
A modifier such as an acrylic polymer, polyurethane, silicone, polyether, polyvinyl ether, polyvinyl chloride, polyvinyl acetate, polyisobutylene, or waxes may be added.

Further, when the photocurable composition according to the present invention is used as an adhesive, an inorganic hollow body such as a glass balloon, an alumina balloon, a ceramic balloon, and the like; Organic hollow bodies such as organic hollow bodies such as vinylidene chloride balloons and acrylic balloons; single fibers such as glass, polyester, rayon, nylon, cellulose and acetate may be added.

When the above glass fiber is blended, a fibrous chip can be added to the composition. However, a high shearing force can be obtained by impregnating a glass woven fabric with the photocurable composition and polymerizing it. Adhesive strength can be obtained.

For the purpose of improving photosensitivity, anthracene, perylene, coronene, tetracene, benzanthracene, phenothiazine, flavin, acridine, ketocoumarin, thioxanthone derivative, benzophenone,
Acetophenone, 2-chlorothioxanthone, 2,4-
A sensitizer such as dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, or isopropylthioxanthone may be appropriately added.

For the purpose of adjusting the time from the irradiation of light until the bonding becomes possible, that is, the pot life, 12-crown-4, 15-crown-5, 18-crown-6,
24-crown-8, 30-crown-10, 2-aminomethyl-12-crown-4, 2-aminomethyl-1
5-crown-5, 2-aminomethyl-18-crown-6, 2-hydroxymethyl-12-crown-4,2
-Hydroxymethyl-15-crown-5, 2-hydroxymethyl-18-crown-6, dicyclohexano-
18-crown-6, dicyclohexano-24-crown-8-dibenzo-18-crown-6, dibenzo-2
4-crown-8, dibenzo-30-crown-10,
Benzo-12-crown-4, benzo-15-crown-5, benzo-18-crown-6,4'-aminobenzo-15-crown-5,4'-bromobenzo-15-
Crown-5,4'-formylbenzo-15-crown-5,4'-nitrobenzo-15-crown-5, bis [(benzo-15-crown-5) -15-ylmethyl] pimelate, poly [(dibenzo- 18-Crown-
6) -co-formaldehyde] or a compound having a cyclic ether structure, or a polyether such as polyethylene glycol, polypropylene glycol or polytetrahydrofuran.

(Processed product using photocurable adhesive sheet)
The photocurable pressure-sensitive adhesive sheet according to the present invention is formed into an adhesive processed product by laminating it on at least one surface or a part of a substrate. That is, the photocurable pressure-sensitive adhesive sheet according to the present invention may not have a substrate, or may be laminated as an adhesive layer on at least one surface or a part of the substrate.

Examples of the base material include various nonwoven fabrics such as rayon or cellulose, films or sheets made of various synthetic resins such as polyethylene, polyester, polystyrene, cellophane, polypropylene, and polyimide; foamed polyethylene, urethane foam, and vinyl chloride foam. Various types of foams, such as polyethylene, polyester, polystyrene, acrylic, ABS, polypropylene, rigid vinyl chloride, synthetic resin plates made of various synthetic resins such as polycarbonate, steel, stainless steel, aluminum, copper,
Sheets or plates made of various metals such as plated steel sheets,
Glass, ceramics, wood, paper, cloth, and the like can be used, and are not particularly limited. Further, the shape of the base material is not limited to a thin shape such as a sheet shape or a plate shape, and may be any shape such as a prism shape, a rod shape, and a shape having an aspheric surface.

(Joining Method of Members) The joining method using the photocurable adhesive sheet according to the present invention is not particularly limited, but is preferably as described in claim 6. Before or after bonding the members together via the sheet, light is applied to the photocurable adhesive sheet. By the irradiation of light, the polymerization reaction of the photopolymerizable compound proceeds, the photocurable adhesive sheet is cured, and the members are firmly joined.

In this case, when joining members made of a light-transmitting material, light may be applied and cured after joining as described above, but in many cases the members are not light-transmitting.
In such a case, the following method can be adopted. That is, after sticking the photocurable adhesive sheet to one member,
Immediately before joining the other members, light is applied to the photocurable adhesive sheet to join them. More preferably, it is desirable to join within 10 minutes. After joining, polymerization and curing proceed at room temperature, and sufficient adhesive strength and heat resistance can be obtained in a short time. In particular, when a photo-cationic polymerizable compound is used as the photo-polymerizable compound A, curing proceeds by a dark reaction at room temperature, and excellent adhesive strength and heat resistance are developed in a short time. In this case, the polymerization reaction is promoted by adding heat or heat and humidity,
It may be cured in a shorter time.

The light irradiated upon curing is appropriately selected depending on the type of the photopolymerizable compound A.
When a photocationically polymerizable compound is used, ultraviolet rays having a wavelength of 400 nm or less emitted from a mercury lamp, a chemical lamp, a xenon lamp, or the like are preferably used.

(Action) In the photopolymerizable composition according to the present invention, the photopolymerization initiator D is activated by light irradiation, and the photopolymerizable compound A is polymerized and cured. Therefore, after curing,
It exhibits excellent adhesive strength, heat resistance and durability. In particular, when a photocationically polymerizable compound is used as the photopolymerizable compound, the curing reaction proceeds as a dark reaction after light irradiation, so that even when the light irradiation is stopped, excellent adhesive strength and heat resistance are obtained. And a cured adhesive having durability. Further, after light irradiation, the photopolymerizable compound develops a high cohesive force with the progress of polymerization due to the progress of the polymerization reaction.

Further, although the resin fine particles B have compatibility with the photopolymerizable compound A, they undergo phase separation as the curing progresses. Therefore, the stress relaxation of the cured product is enhanced by the resin fine particles B, and the adhesive strength is further enhanced. Since the resin fine particles B have compatibility with the photopolymerizable compound A,
At the time of light irradiation, it is finely dispersed in the photopolymerizable composition and does not prevent light from penetrating into the photopolymerizable composition.

Furthermore, since the polymer C having excellent compatibility with the resin fine particles B was added, the resin fine particles B were finely dispersed during storage of the photopolymerizable composition according to the present invention before curing. The state is kept stable.

When a tacky polymer is used as the polymer C, a tacky adhesive having tackiness before curing can be obtained, and the workability in the bonding operation is improved.

[0074]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to the following examples.

(Materials used) Epoxy resin 1 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd.)
Epicoat 828) Epoxy resin 2 ... (manufactured by Nippon Rika Co., Ltd., trade name: Rica Resin BPO20E) Epoxy resin 3 ... (manufactured by Yuka Shell Epoxy Co., Ltd., trade name:
Epicoat 1004) Resin fine particles: Nippon Synthetic Rubber Co., Ltd., acrylic rubber fine particles (no functional group on the particle surface) Resin fine particles: Nippon Synthetic Rubber Co., Ltd., acrylic rubber fine particles (COOH group on the particle surface) Ethyl acrylate polymer: weight average Molecular weight Mw = 7
10,000 ethyl acrylate polymer: weight average molecular weight Mw = 7
100,000, a copolymer of ethyl acrylate-glycidyl methacrylate in a weight ratio of 95: 5. Surfactant: manufactured by Daihachi Chemical Co., product number: DP8R Photocationic polymerization initiator: manufactured by Asahi Denka Co., trade name: Optomer SP170

(Example 1) As the photopolymerizable compound, 40 parts by weight of the epoxy resin 1 and 10 parts of the epoxy resin 2 were used.
Parts by weight, 5 parts by weight of resin fine particles, 50 parts by weight of an ethyl acrylate polymer as the polymer C, and 0.5 parts by weight of the above-mentioned photopolymerization initiator together with 100 parts by weight of ethyl acetate as a solvent. The mixture was stirred at a room temperature of 23 ° C. with a stirrer (trade name: Homodisper L) manufactured by Tokushu Kika Kogyo Co., Ltd. at 3000 rpm until the stirring speed became uniform.
An adhesive composition solution as a photopolymerizable composition solution was obtained.

The above adhesive composition solution was applied to a 50 μm-thick PET film whose surface had been release-treated using a roll coater so that the thickness after drying would be 50 μm, and then dried. An adhesive sheet was obtained. In this photocurable pressure-sensitive adhesive sheet, in order to protect the pressure-sensitive adhesive surface, polyethylene-laminated high-quality paper (hereinafter, paper separator) that had been release-treated with silicone was laminated on the pressure-sensitive adhesive surface.

(Examples 2 to 4 and Comparative Examples 1 to 3) Except that the materials used were changed as shown in Table 1 below,
An adhesive sheet was obtained in the same manner as in Example 1.

Example 5 Instead of the ethyl acrylate polymer, 50 parts by weight of an ethyl acrylate monomer was added. Further, as a photoradical polymerization initiator, 0.1 g of Irgacure 1700 manufactured by Ciba-Geigy Corporation was used.
The same materials as in Example 1 were used except that they were blended in parts by weight. Dissolved oxygen was removed from the composition having such a composition by bubbling with nitrogen gas for 20 minutes. Thereafter, the composition solution from which dissolved oxygen has been removed is coated on a PET film having a surface subjected to release treatment so as to have a thickness of 50 μm, and the coated surface is further subjected to transparent PET having a surface subjected to release treatment. Covered with film. Using a fluorescent lamp having a maximum emission wavelength at 400 nm, near-ultraviolet light substantially not containing light having a wavelength of 360 nm or less is applied to the thus obtained laminate so that the light intensity becomes 1 mW / cm ^2. Irradiation was performed for 5 minutes to polymerize the ethyl acrylate monomer to obtain a curable adhesive sheet as an ethyl acrylate polymer.

(Evaluation) The curable pressure-sensitive adhesive sheet obtained as described above was subjected to the following initial capacity, adhesive strength after curing, heat resistance in dry state, heat resistance in wet state, haze value, The storage stability was evaluated.

Initial adhesive strength: While peeling off the paper separator of the adhesive sheet, but in Example 5, one of the PET films was peeled off, the adhesive sheet was applied at 100 ° C. to a polyimide film having a thickness of 50 μm. Thermal lamination was performed. The lamination pressure was 3 kg / cm, and the lamination speed was 2 m / min.

The laminate obtained as described above was cut to a width of 10 mm, the release PET film of the adhesive sheet was peeled off, and ultraviolet light having a wavelength of 360 nm was applied to the adhesive sheet with an ultra-high pressure mercury lamp. Was 3 J / cm ² . After that, the laminate is 25 mm wide x 1 long.
1 on a 000 mm x 0.3 mm thick glass epoxy board
Bonding was performed by heat lamination at 00 ° C. to obtain an adhesive sample. The adhesive sample was allowed to stand at room temperature for 5 minutes, peeled 180 ° at a peeling speed of 50 mm / min, the peel strength was measured, and the result was defined as the initial adhesive strength.

Adhesive force after curing (180 ° peel force): The adhesive sample obtained in the evaluation of the initial adhesive force was further left at room temperature for one day, and the 180 ° peel strength was measured in the same manner.
The adhesive strength after curing was used.

Heat resistance in dry state: The adhesive sample prepared for the measurement of the initial adhesive strength was subjected to a heat treatment at 23 ° C. and a relative humidity of 65%.
After maintaining the condition for 1 day and curing the adhesive sheet,
It was dried at 00 ° C. for 30 minutes, further placed in a gear oven at 300 ° C., and exposed for 1 hour. Thereafter, the presence or absence of peeling or foaming of the bonded end face was visually observed.

Heat resistance in wet state: The adhesive sample prepared in the evaluation of the initial adhesive strength was subjected to a heat treatment at 23 ° C. and a relative humidity of 6
After being left to cure at 5% for one day, it was exposed to an atmosphere of 40 ° C. and 95% relative humidity for 48 hours, and then exposed to a gear oven at 220 ° C. for 1 hour. After a while
The presence or absence of peeling and foaming of the bonding face was visually observed.

Measurement of haze value: The haze value of the adhesive sheet before and after curing was measured according to JIS K7105. In Table 1 below, haze values for a sheet having a thickness of 100 μm are shown.

Evaluation of storage stability: After storing each of the adhesive sheets obtained in Examples and Comparative Examples at 40 ° C. for one month,
Were evaluated in the same manner. The evaluation results are shown in Table 1 below.
Shown in

[0088]

[Table 1]

Comparison between Example 1 and Comparative Example 1 shows that, in Example 1, in which the epoxy resin 2 having poor compatibility with the resin fine particles made of acrylic rubber is mixed, the resin fine particles made of acrylic rubber are hardened after curing. It can be seen that the adhesive force after curing is increased because of micro phase separation.

Further, by comparing Example 1 with Comparative Example 2, it can be seen that in Example 1, the compatibility between the ethyl acrylate polymer and the resin fine particles composed of acrylic rubber is excellent, so that even after storage for a long period of time, It can be seen that the adhesive strength and heat resistance after curing were enhanced.

Comparison between Example 1 and Comparative Example 3 shows that the addition of the resin fine particles did not lower the heat resistance in Example 1. This is presumably because the resin fine particles are crosslinked, so that migration to a low molecular weight epoxy resin does not occur.

Further, when Example 1 and Comparative Example 3 are compared, it can be seen that the adhesive strength is increased in Example 1 due to an increase in the haze value after curing. This is presumably because the microphase separation between the resin fine particles and the epoxy resin after curing has enhanced stress relaxation at the time of peeling, thereby increasing the adhesive strength.

Further, by comparing Example 1 with Examples 2 to 4, Examples 2 to 4 in which the ethyl acrylate copolymer was blended showed that the ethyl acrylate copolymer and the epoxy resin were mixed after irradiation with light. It can be seen that the heat resistance is enhanced by the crosslinking.

When Examples 1 and 2 are compared with Examples 3 and 4, the dispersibility of the resin fine particles is increased by the addition of the surfactant, and the haze value of the composition before curing is reduced. You can see that. Accordingly, it is possible to improve the stability of the photopolymerizable composition and the photocurable adhesive sheet during storage, to reduce the amount of light irradiation during light irradiation, to stabilize the phase separation structure after curing, and to improve the adhesive strength. It can be understood that it can be achieved.

When comparing Example 1 with Example 5, in Example 5, the heat resistance when wet was improved. This is because in Example 5, ethyl acrylate was polymerized by photoradical polymerization to obtain an ethyl acrylate polymer,
Thereby, it is considered that a decrease in adhesive strength at a high temperature is suppressed, and heat resistance is enhanced.

[0096]

In the photopolymerizable composition according to the first aspect of the present invention, the photopolymerization initiator D is activated by light irradiation, and the polymerization of the photopolymerizable compound A progresses and is cured. Therefore, after the curing is completed, good adhesive strength is exhibited.

Moreover, the resin fine particles B are blended, and the resin fine particles B phase-separate from the polymer of the photopolymerizable compound A after curing, so that the stress relaxation of the cured product is enhanced,
Thereby, the adhesive strength is further increased.

Further, since the resin fine particles B are finely dispersed in the photopolymerizable composition before curing, they do not hinder the penetration of light. Therefore, compared with a conventional photopolymerizable composition that previously employs a phase separation structure, the amount of light irradiation can be reduced, and even when the film thickness of the photopolymerizable composition is large, light can be sufficiently transmitted to a deep part. Hardening proceeds surely throughout.

Further, since the polymer C has compatibility with the resin fine particles B, the state in which the resin fine particles are finely dispersed is kept stable during storage before curing, and therefore, the storage stability is enhanced. .

Furthermore, when a polymer having adhesiveness is used as the polymer C, the adhesiveness is exhibited before curing, so that the workability of the joining operation can be improved, and the polymer C is used as a curable adhesive. be able to.

Therefore, when the photopolymerizable composition according to the first aspect of the present invention is used, it has excellent storage stability, is cured by light irradiation, and has excellent adhesive strength, heat resistance and durability. An adhesive cured product can be obtained.

According to the second aspect of the present invention, the thickness of 100 μm
Since the haze value of the photopolymerizable composition per m is 20% or less before light irradiation, the composition is excellent in transparency, light travels to the inside, and the curing reaction proceeds reliably by light irradiation. ,
After curing after light irradiation, the resin fine particles B phase-separate from the polymer of the photopolymerizable compound A, and the haze value corresponding to
~ 100%. Therefore, since the cured matrix and the resin fine particles have a strong interaction due to the phase separation, the cured product exhibits both cohesive force and stress relaxation, and exhibits excellent adhesive strength and heat resistance.

In the invention according to claim 3, the polymer C
However, since it contains a functional group that reacts with photopolymerizable compound A after light irradiation, curing proceeds after light irradiation, and at the same time, the above functional group of polymer C reacts with photopolymerizable compound A, thereby causing crosslinking and the like. The adhesiveness before curing and the high adhesive strength after curing can be compatible, and the heat resistance of the cured adhesive product can be further increased by increasing the crosslink density after curing.

In the fourth aspect of the present invention, the polymer C
Is obtained by photoradical polymerization of a photopolymerizable composition containing a radical polymerizable monomer or oligomer, so that the photopolymerizable compound A and the resin fine particles B
And a photopolymerization composition containing a photopolymerization initiator D, a radically polymerizable monomer or oligomer for constituting the polymer C, and a photoradical polymerization initiator. The photopolymerizable composition according to the invention described in (1) can be easily obtained.

The photocurable pressure-sensitive adhesive sheet according to the fifth aspect of the present invention is constituted by using the photopolymerizable composition according to any one of the first to third aspects. It can be easily affixed to an adherend by utilizing the property, and complicated work such as pressing or temporarily fixing members under severe conditions can be omitted, and workability of joining work can be improved. In addition, since the curing progresses by light irradiation and exhibits excellent adhesive strength and heat resistance, the members can be firmly joined by joining the members according to the invention described in claim 6.

In the member joining method according to the sixth aspect of the present invention, the members are irradiated with light before or after the members are bonded to each other via the photocurable adhesive sheet. The adhesive sheet can be easily bonded by utilizing the adhesiveness thereof, and can be hardened by light irradiation, thereby firmly joining the members.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) G03F 7/027 G03F 7/027 F term (reference) 2H025 AA14 AB15 AB20 AC01 AC04 AC08 AD01 BC23 BC24 BD03 BD10 BD13 BD23 BD53 BH00 CA00 CB11 CB14 CB41 CB52 4J004 AA04 AA05 AA06 AA07 AA08 AA10 AA11 AA13 AA14 AA15 AA17 AB07 BA02 CA02 CA04 CA05 CA06 CA07 CA08 CB01 CB02 CB04 CC02 CC08 CE03 DA02 DB04 FA05 FA08 4002 EC061 EC062 EC071 EC072 EC121 EC122 EC201 EC202 EC231 EC232 EC251 EC252 EC311 EC312 EC371 EC372 ED001 ED002 EE021 EE022 EF001 EF002 EK031 EK032 EL022 FA061 FA062 HB44 HC19 HC22 JA09 JB08 JB09 KA03 LA20 LA10

Claims (6)

[Claims] 1. A: a photopolymerizable compound; B: resin fine particles which are compatible with the photopolymerizable compound A before light irradiation, and which proceed with curing and phase-separate from the photopolymerizable compound A after light irradiation. And C: a polymer having compatibility with the resin fine particles B, and D: a photopolymerization initiator. 2. The haze value according to JIS K7105 before light irradiation is less than 20% per 100 μm thickness, and after the light irradiation and curing progress, the haze value is 10%.
The photopolymerizable composition according to claim 1, wherein the content is in the range of 20 to 100% per 0 µm. 3. The photopolymerizable composition according to claim 1, wherein the polymer C contains a functional group that reacts with the photopolymerizable compound A after light irradiation. 4. The polymer C obtained by photo-radical polymerization of a photo-polymerizable composition containing a radical-polymerizable monomer or oligomer.
3. The photopolymerizable composition according to any one of 3. 5. A photo-curable pressure-sensitive adhesive sheet comprising the photopolymerizable composition according to claim 1 as a main component. 6. A light-curable adhesive sheet is irradiated with light and cured before or after bonding members together via the light-curable adhesive sheet according to claim 5. Method of joining members.