JPH10130597A - Curable tacky adhesive sheet and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable tacky adhesive sheet having sufficiently high initial tackiness and easily curable to form a cured product having excellent adhesive strength by impregnating a specific photopolymerizable composition into a fibrous substrate and forming a tacky adhesive polymer under specific condition. SOLUTION: The objective curable tacky adhesive sheet 1 is produced by preparing a photopolymerizable composition containing a monomer such as methyl (meth)acrylate to form a tacky adhesive polymer, a photo-radical polymerization initiator such as an acylphosphine oxide, a compound containing epoxy group such as bisphenol A epoxy resin and a compound such as a diazonium salt to induce the opening of the ring of epoxy group by the irradiation of lithe, impregnating the prepared composition into a fibrous substrate such as glass cloth 2 and forming a tacky adhesive polymer by irradiating the impregnated composition with light having a wavelength range capable of activating the photo-radical polymerization initiator and free from the action to induce the ring-opening of epoxy group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a curable pressure-sensitive adhesive sheet and a method for producing the same, and more particularly, to a curable pressure-sensitive adhesive sheet which is normally tacky and can be cured by irradiation with light. The present invention relates to a landing sheet and a method for manufacturing the same.

[0002]

2. Description of the Related Art Acrylic pressure-sensitive adhesives have heat resistance, weather resistance,
Because of its excellent oil resistance, it is widely used for various adhesive processed products such as adhesive tape. However, an acrylic pressure-sensitive adhesive could not exhibit a high peel resistance like an adhesive.

Therefore, a curable adhesive has been proposed which has both the easy workability of an acrylic pressure-sensitive adhesive and the high bonding strength and coating strength of an adhesive. For example, JP-A-2-272076 discloses an adhesive tape using a pressure-sensitive thermosetting adhesive composed of a photopolymerizable composition containing an acrylate monomer and an epoxy resin.

When members are to be joined to each other using the adhesive tape described in the above-mentioned prior art, after irradiating the photopolymerizable composition with light to polymerize an acrylate monomer and develop adhesiveness, Adhesive strength can be obtained by attaching to an adherend and curing the epoxy resin by heating after attaching.

However, even when the adhesive tape described in JP-A-2-272076 is used, a sufficient bonding strength cannot be obtained depending on the adherend.
In addition, in the method described in JP-A-2-272076, since heat is used for curing the epoxy resin, a material having poor heat resistance cannot be used as the adherend. That is, there is a problem that the material of the adherend is limited.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a film which has a sufficient initial adhesive strength under normal conditions, can be easily cured by irradiating light, and has excellent adhesive strength after curing. An object of the present invention is to provide a curable adhesive sheet and a method for producing the same.

[0007]

Means for Solving the Problems Although not yet known, the inventors of the present application have previously described an acrylic polymer as a curable adhesive which can be used for joining members having insufficient heat resistance.
A curable adhesive sheet containing an epoxy resin and a compound which is exposed to light to induce ring opening of an epoxy group was proposed.
In this curable adhesive sheet, since the epoxy resin is cured by light irradiation, the adhesive can be applied to the adherend only by irradiating light before or after attaching the curable adhesive sheet to the adherend. The curable adhesive sheet can be firmly bonded, and the heat resistance of the adherend does not matter.

However, as described above, even in a curable adhesive sheet that is cured by irradiating light, the adhesive strength after curing may not be sufficient depending on the adherend. Therefore, as a result of intensive studies to further increase the adhesive strength after curing, it was found that if the fiber base material was combined with the curable adhesive sheet, the adhesive strength could be increased.
The present invention has been made.

That is, the invention according to claim 1 forms a composition comprising an adhesive polymer, a compound having an epoxy group, and a compound which is irradiated with light to induce ring opening of the epoxy group. A curable pressure-sensitive adhesive sheet comprising a fiber substrate laminated in or on the sheet.

Preferably, as described in claim 2, a fiber base having a basis weight of 1.0 to 1000 g / m ² is used. The invention according to claim 3 is a method for producing the curable adhesive sheet according to the invention according to claim 1 or 2, wherein a monomer for obtaining an adhesive polymer, a photo-radical polymerization initiator, Impregnating a fiber substrate with a photopolymerizable composition containing a compound containing a group and a compound that is irradiated with light to induce ring opening of an epoxy group; and starting the photoradical polymerization in the photopolymerizable composition. Activating the agent, but irradiating light in a wavelength region that does not induce ring opening of the epoxy group, and forming a tacky polymer. .

The invention described in claim 4 is the first invention.
Or the method for producing a curable pressure-sensitive adhesive sheet according to 2, wherein a monomer for obtaining an adhesive polymer, a photoradical polymerization initiator, a compound containing an epoxy group, and an epoxy group Activating the photo-radical polymerization initiator in a photopolymerizable composition containing a compound that induces ring opening of, but irradiates light in a wavelength region that does not induce ring opening of the epoxy group to form an adhesive polymer. And forming a curable pressure-sensitive adhesive layer by laminating the curable pressure-sensitive adhesive layer on a fiber base material.

Hereinafter, the present invention will be described in detail. Adhesive Polymer In the present invention, the above-mentioned adhesive polymer is used to give an initial adhesive force to the curable adhesive sheet so that it can be used as an adhesive sheet.

The adhesive polymer may be compatible with the above-mentioned resin having an epoxy group and the compound which induces a ring-opening reaction of the epoxy group, as long as the polymer does not cause macrophase separation. May be used.
Here, macro phase separation refers to a phenomenon in which an adhesive polymer completely separates into phase with a resin having an epoxy group and a compound which induces a ring-opening reaction of the epoxy group. It refers to a state in which any or all of the compounds that induce the ring-opening reaction of the epoxy group are separated in a transparent state, and is different from a state in which the compound is merely clouded by microphase separation.

As for the adhesive polymer which can be used in the present invention, as long as it does not cause macrophase separation with a resin having an epoxy group and a compound which induces a ring-opening reaction of the epoxy group as described above, a conventional adhesive composition is used. An appropriate high molecular weight polymer used for the reaction can be used. Examples of such adhesive polymers include acrylic polymers, polyesters, polyurethanes, silicones, polyethers, polycarbonates, polyvinyl ethers, polyvinyl chlorides, polyvinyl acetates, polyisobutylenes, and the like. The adhesive polymer may be a copolymer containing a monomer as a main component of these polymers.

The molecular weight of the adhesive polymer is preferably large, and the weight average molecular weight is preferably in the range of 100,000 to 5,000,000, more preferably 200,000 to 3,000,000, and further preferably 600 to 2,000,000. When the weight average molecular weight of the adhesive polymer is less than 100,000, the cohesive force of the curable adhesive sheet is insufficient, and it may be difficult to maintain the shape of the sheet. In some cases, the viscosity of the composition containing the adhesive polymer and the resin having an epoxy group becomes too high to form a sheet.

Among the various polymers described above, acrylic polymers are used because they are commonly used as a main component of a pressure-sensitive adhesive in order to exhibit a superior initial adhesive strength and control of the adhesive properties is easy. Is preferred.

The structure of the acrylic polymer is not particularly limited, and may be, for example, a homopolymer structure, a random copolymer structure, a block copolymer structure, an alternating copolymer structure, a stereoregular structure, a multibranched structure. , A star-shaped structure, a dendritic structure, a ladder structure, a ring structure, a helical structure and the like.

A more preferred example of the acrylic polymer is a polymer in which a unit composed of (meth) acrylic acid ester is contained in the acrylic polymer in an amount of 20% by weight or more, and the alkyl group has 1 to 14 carbon atoms. A polymer or copolymer of the (meth) acrylate monomer (a) may be mentioned.

Further, the above-mentioned copolymer includes an alkyl (meth) acrylate monomer (a) and a vinyl monomer (b) having an unsaturated bond copolymerizable with the alkyl (meth) acrylate monomer (a). And copolymers. The method for producing such a copolymer is not particularly limited, and it can be produced by a known method such as radical polymerization, anionic polymerization, coordination polymerization, or photopolymerization.

The alkyl (meth) acrylate monomer (a) includes methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-
Examples thereof include octyl (meth) acrylate, isononyl (meth) acrylate, and isomyristyl (meth) acrylate.

The vinyl monomer (b) is not particularly limited as long as it is a compound having an unsaturated bond copolymerizable with the alkyl (meth) acrylate monomer (a).

Examples of the vinyl monomer (b) include:
(Meth) acrylonitrile, N-vinylpyrrolidone, isovoltanyl (meth) acrylate, N-acryloylmorpholine, benzyl (meth) acrylate, glycidyl (meth) acrylate, N-vinylcaprolactone, N-vinylpiperidine (meth) acrylic acid, anhydride Maleic acid and the like can be mentioned.

More preferably, as the adhesive polymer, an acrylic polymer obtained by subjecting a photopolymerizable composition containing an acrylic monomer to photoradical polymerization is used. In this case, an acrylic polymer is obtained by photoradical polymerization by irradiating the photopolymerizable composition with light. Therefore, if the acrylic polymer and the photo-radical polymerization initiator are contained in the photopolymerizable composition together with the resin having an epoxy group and the compound that induces a ring-opening reaction of the epoxy group, irradiation with light allows The curable adhesive sheet according to the present invention can be easily obtained.

As will be described later, when a photo-cationic polymerization initiator is used as the compound that induces the ring-opening reaction of the epoxy group, light is also applied to cure the curable adhesive sheet. Can be performed. That is, only by employing a single method of irradiating light, not only can the curable adhesive sheet be obtained from the photopolymerizable composition, but also the curing of the curable adhesive layer can be performed. Can play. However, in this case, the light irradiated when forming the acrylic polymer by photoradical polymerization and the light irradiated when curing the curable adhesive sheet may have different wavelength ranges. is necessary.

Further, in order to induce a reaction for opening a ring of an epoxy group, a larger energy is required than in the case of the photoradical polymerization. Therefore, more preferably, at the time of the photoradical polymerization, light of a wavelength region of 360 nm or more is irradiated to perform photoradical polymerization, and when a ring opening reaction of an epoxy group is induced, light having a wavelength of less than 360 nm is emitted. It is desirable to use.

The photo-radical polymerization initiator activated by light in a wavelength region of 360 nm or more includes 360 n
Compounds that must be activated by light having a wavelength of at least m and that do not cause energy transfer to compounds that induce ring-opening reactions of epoxy groups with light of less than 360 nm are preferred. Preferred examples of such a photoradical polymerization initiator include, for example, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α′-dimethylacetophenone, methoxyacetophenone , 2,2-dimethoxy-2
Acetophenone derivative compounds such as phenylacetophenone; benzoin ether compounds such as benzoin ethyl ether and benzoin propyl ether; ketal derivative compounds such as benzyl dimethyl ketal; halogenated ketones; acylphosphine oxides; acylphosphonates; , 6-Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide.

Among the above examples of the photopolymerization initiator, in particular, 3
Acylphosphine oxide, acylphosphonate, bis- (2,6-dimethoxybenzoyl) -2, which has a high absorption coefficient for light in a wavelength region exceeding 60 nm.
4,4-Trimethylpentylphosphine oxide is preferred.

Examples of lamps used for light irradiation in the photoradical polymerization include low-pressure mercury lamps, medium-pressure mercury lamps,
A high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, and the like can be used.

Compound Having an Epoxy Group The compound having an epoxy group used in the present invention undergoes ring-opening polymerization by the action of a compound that induces a ring-opening reaction of the epoxy group when irradiated with light, to thereby form a curable epoxy resin. It is used to cure the adhesive sheet.

The compound having an epoxy group includes
There is no particular limitation as long as it contains an epoxy group (oxa-cyclopropyl group). For example, bisphenol A epoxy resin, bisphenol F epoxy resin,
Novolak type epoxy resins, alicyclic aliphatic epoxy resins, glycidyl ester compounds and the like can be mentioned.

Compound Inducing Ring-Opening Reaction of Epoxy Group In the present invention, the curable adhesive layer is cured by causing a ring-opening reaction of the epoxy group of the resin having an epoxy group to polymerize. In order to induce the ring opening of the epoxy group, a compound which induces a ring opening reaction of the epoxy group is blended as described above, and such a compound is opened by irradiation of light. Any compound that induces a ring is used. In addition, as the light, ultraviolet light having a wavelength of less than 360 nm is preferable because the energy intensity is large and the ring opening of the epoxy group proceeds rapidly.

Examples of the compound which induces a ring opening reaction of an epoxy group by light include onium salts, organometallic complexes and the like. Examples of the onium salts include diazonium salts, sulfonium salts, and iodonium salts. Further, as the organometallic complexes, for example, iron-allene complex, titanocene complex,
An arylsilanol-aluminum complex and the like can be mentioned. More preferably, a photocationic reaction polymerization initiator is used as a compound that induces a reaction for opening a ring of an epoxy group.

Examples of the above-mentioned cationic photopolymerization catalyst include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts and the like. More specifically,
For example, Optomer SP-150 (manufactured by Asahi Denka Kogyo),
Optomer SP-170 (Asahi Denka Kogyo), UVE-
1014 (manufactured by General Electronics), CD-1
Commercially available compounds such as 012 (manufactured by Sartomer) can be used.

The lamp used for the light irradiation includes:
Preferably, those having an emission distribution at a wavelength of 360 nm or less are used. For example, 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, a micro-wave excitation mercury lamp, a metal halide lamp, or the like is used. be able to. In this case, to prevent hardening of only the surface layer and realize internal hardening, 320 n
m or less may be cut and irradiated.

Mixing ratio In the curable pressure-sensitive adhesive sheet according to the present invention, the mixing ratio of the above-mentioned adhesive polymer and the compound having an epoxy group is appropriately determined according to the target initial adhesive strength and the adhesive strength after curing. Although it is determined and not particularly limited, preferably, a compound having an epoxy group is blended in a ratio of 10 to 300 parts by weight with respect to 100 parts by weight of the adhesive polymer.

The compounding ratio of the compound having an epoxy group is 1
If the amount is less than 0 parts by weight, even when cured by irradiating light, a sufficient adhesive strength may not be obtained. In some cases, the initial adhesion may not be sufficiently obtained.

The compound which induces the ring opening of the epoxy group varies depending on the kind thereof. The proportion of the compound is not particularly limited. For example, when the above-mentioned photocationic polymerization catalyst is used, Is 0.01 to 100 parts by weight of the compound having an epoxy group.
It is preferred to be within the range of 5 parts by weight. When the compounding ratio of the photocationic polymerization catalyst is less than 0.01 part by weight, the ring-opening reaction of the epoxy group may not be able to proceed sufficiently even when irradiated with light, and the adhesive curing with high adhesive strength may be performed. In some cases, the compound cannot be obtained, and even if it is added in an amount of more than 5 parts by weight, the effect of promoting the curing of the compound having an epoxy group does not further increase, and the initial adhesive strength may decrease.

The curable adhesive layer according to the present invention does not inhibit the object of the present invention, in addition to the adhesive polymer, the compound having an epoxy group and the compound which induces ring opening of the epoxy group. Known tackifying resins, extenders and the like may be appropriately blended within the range.

For example, for the purpose of improving the tackiness of the curable adhesive layer of the present invention, a rosin resin, a modified rosin resin, a terpene resin, a terpene phenol resin, an aromatic modified terpene resin, a C5 or C9 A tackifying resin such as a petroleum resin or a chroman resin may be added.

In particular, when the adherend is a polyolefin, a strong adhesive force can be exhibited.
Rosin-based resins and petroleum resins are preferred. Further, for the purpose of improving coatability, a thickener such as acrylic rubber, epichlorohydrin rubber, isoprene rubber, butyl rubber, colloidal silica, a thixotropic agent such as polyvinylpyrrolidone, calcium carbonate, titanium oxide, and a bulking agent such as clay. It may be added.

[0041] As described above fibrous base material, the adhesive and pressure-sensitive adhesive sheet according to the invention of claim 1, includes a fiber base in the sheet,
Thereby, the adhesive strength is increased.

The weight of the fiber base is preferably 1.0
To 1000 g / m ² , more preferably 5.0 to 500 g
/ M ² , more preferably 10 to 300 g / m ² . The weighing less than 1.0 g / m ^2, may effect of suppressing volume shrinkage during curing pressure-sensitive curable adhesive sheet using a fibrous substrate is not sufficient, when it exceeds 1000 g / m ^2, the fiber base material May affect the bonding interface, reduce the bonding area and reduce the bonding strength.

The structure of the fiber substrate may be a woven fabric or a non-woven fabric, and a fiber substrate having an arbitrary structure can be used. Further, the material constituting the fiber base material is not particularly limited, and polyester,
Nylon, rayon, glass fiber, cotton, silk and any other materials can be used. Further, in order to enhance the adhesiveness with the curable adhesive sheet, the surface of the fiber substrate may be treated with an appropriate surface treating agent, or may be subjected to corona treatment or plasma treatment. The surface treatment is not particularly limited.

The method for producing the curable adhesive sheet according to the first and second aspects of the present invention is not particularly limited, but preferably, the production method and the method according to the third aspect of the present invention. The manufacturing method according to the invention described in Item 4 can be used.

In the production method according to the third aspect of the present invention, the monomer for obtaining the adhesive polymer, a photo-radical polymerization initiator, a compound having an epoxy group, and a compound having an epoxy group opened by being irradiated with light. Impregnating a fiber substrate with a photopolymerizable composition containing a compound that induces a ring, and thereafter, in the photopolymerizable composition, activates a photoradical polymerization initiator, but does not induce ring opening of an epoxy group. It is performed by irradiating light in a wavelength region to form an adhesive polymer and form a sheet.

On the other hand, in the production method according to the present invention, a monomer for obtaining a tacky polymer, a photo-radical polymerization initiator, a compound containing an epoxy group,
A photopolymerizable composition containing a compound that is irradiated with light and induces ring opening of an epoxy group is activated by irradiating light in a wavelength region that activates a photoradical polymerization initiator but does not induce ring opening of an epoxy group. Then, the curable adhesive layer is formed into a sheet, and thereafter, the curable adhesive layer is laminated on the fiber base material.

That is, the step of irradiating light for forming the adhesive polymer may be performed after impregnating the photopolymerizable composition into the fiber base material, or may be performed by previously irradiating the light with the curable composition. After forming the adhesive layer, the adhesive layer may be laminated on the fiber base material.

In the manufacturing method according to the third and fourth aspects of the present invention, a single-layer fiber substrate or two or more layers of fiber substrates may be used as the fiber substrate. Further, in the manufacturing method according to the fourth aspect of the present invention, when laminating the curable adhesive layer on the fiber base, pressure is applied after laminating the curable adhesive layer on the fiber base. Thus, the fiber base may be buried in the curable adhesive layer, or the curable adhesive layer may be laminated on both surfaces of the fiber base.

Substrate Further , the curable pressure-sensitive adhesive sheet according to the present invention can be used as a double-sided pressure-sensitive adhesive tape in the form as it is, for example, in order to bond the bonding member to the adherend with the bonding member interposed therebetween. It may be used as described above, or may be formed as an adhesive layer on at least one surface of an appropriate substrate such as a synthetic resin film or cloth.

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, cellophane, polypropylene, polystyrene, and polyimide; foamed polyethylene, urethane foam, and neoprene foam. , Various foams such as polyvinyl chloride, resin plates made of various synthetic resins such as polystyrene, ABS, acrylic, polypropylene, and polyethylene, steel, stainless steel,
Sheets or plates made of various metals such as copper and aluminum, glass, wood, paper, cloth, and the like can be used.
There is no particular limitation. Further, the shape of the substrate is not limited to a thin shape such as a sheet or a plate, and may be any shape such as a prism, a rod, a sphere, and a shape having an aspheric surface.

When joining members using the curable adhesive sheet according to the present invention, before joining the joining member to the adherend via the curable adhesive sheet, After the alignment, light in a wavelength region that induces ring opening of the epoxy group is irradiated to cure the curable adhesive sheet. In this case, preferably,
"Before bonding" means before bonding and before curing of the compound having an epoxy group is completed. When the curing of the compound having an epoxy group is completed, the curable pressure-sensitive adhesive sheet becomes too hard, and a sufficient initial adhesive strength may not be obtained.

Preferably, the wavelength is less than 360 nm.
And the light intensity is 5 mW / cm ^TwoMore UV light
Can be. For light with a wavelength greater than 360 nm, the energy
-Insufficient strength may require time for curing
5mW / cm^TwoWhen using ultraviolet light with a light intensity of less than
Similarly, curing may take a long time.

Note that if the curing member is irradiated with light before the joining member is joined to the adherend and the curing of the curable adhesive sheet is advanced, the joining member and the adherend are not irradiated with light. Further, it is possible to prevent the deterioration of the joining member and the adherend due to light. Therefore, when joining an adherend or a joining member that is likely to be deteriorated by light irradiation, it is desirable to irradiate the curable adhesive sheet in advance with light as described above. Further, when one of the adherend and the bonding member is easily deteriorated by light and the other is hardly deteriorated by light, the light is irradiated by bonding a curable adhesive sheet to the other member side, Thereafter, it may be bonded to the one member.

Applications The curable pressure-sensitive adhesive sheet according to the present invention can be used for various pressure-sensitive adhesive applications. However, since the bonding strength increases after the curing treatment, it is used for building materials and home electric appliances that require sufficient bonding strength. It is suitable for applications requiring durability such as members and automobile members.

[0055] In the adhesive sheet adhesive and pressure-sensitive according to the invention described in the action claim 1, is not necessarily clear cause that may enhance the adhesive strength after curing by using a fiber base material, the following fiber substrate It is thought to be due to the action of

That is, when the compound having an epoxy group is polymerized, volume shrinkage occurs in the reaction system. Due to this volume shrinkage, a partial stress may be generated in the adhesive sheet or peeling of the adhesive sheet from the interface may be caused. Therefore, the volume shrinkage may lower the adhesive strength. Probably. On the other hand, according to the first aspect of the present invention, since the fibrous base material includes the fibrous base material, the fibrous base material suppresses the volume shrinkage, prevents a decrease in adhesive strength, and increases the adhesive strength as a result. It is thought that there is.

In the method for producing a curable pressure-sensitive adhesive sheet according to the third aspect of the present invention, the fiber base material is impregnated with the photopolymerizable composition. Since the contact area between the curable adhesive and the fiber base material is large, the effect of suppressing the volume shrinkage is increased, and a curable adhesive sheet having even higher adhesive strength can be provided.

According to the fourth aspect of the present invention, since the fibrous base material is laminated after forming the curable adhesive layer, the curable adhesive layer can be formed using various known film-forming methods. Since it is only necessary to laminate the fiber base after molding
The productivity of the curable adhesive sheet using the fiber base material can be increased.

[0059]

The present invention will be clarified by the following non-limiting examples.

Example 1 In a 4 L separable flask, 36 g of 2-ethylhexyl acrylate, 84 g of N-vinylpyrrolidone, 36 g of an epoxy resin (trade name: Epicoat # 828, manufactured by Yuka Shell Epoxy), and a photo radical Polymerization initiator (Ciba Geigy Industries, trade name: C
GI-1700) and 0.5 g of a cationic photopolymerization initiator (manufactured by Asahi Denka Kogyo Co., Ltd., trade name: SP-170), and stirred until uniform, mixed, and then nitrogen gas was added. Bubbling was performed for 20 minutes to remove dissolved oxygen and obtain a photopolymerizable composition.

On a polyethylene terephthalate (PET) film whose surface has been release-treated, a weight of 100
g / m ² of glass cloth, the above-mentioned photopolymerizable composition is dropped so that the glass cloth is completely immersed, and another PET film whose surface is subjected to a release treatment is coated thereon, and the photopolymerizable composition is coated. The thickness of the material layer was adjusted to be 200 μm.

The laminate obtained as described above was added with 400 n
m, using a fluorescent lamp having a maximum emission wavelength, irradiating near-ultraviolet light substantially not containing light in a wavelength region of 360 nm or less such that the light intensity becomes 1 mW / cm ² for 15 minutes;
The curable adhesive sheet 1 shown in FIG. 1 was obtained. In FIG. 1, 1a is a curable adhesive layer, 2 is a glass cloth,
Reference numeral 4 denotes a PET film.

After irradiating the curable pressure-sensitive adhesive sheet with light having a light intensity of 300 m or more and less than 360 nm and a light intensity of 25 mW / cm ² for one minute, one of the PET films was peeled off, and a coating made of stainless steel (SUS304) was applied. The test piece was adhered to the adherend and pressed back and forth on a PET film on the back side by reciprocating a 2 kg roller once to obtain a test piece having a cured adhesive sheet adhered to the adherend.

The T-peeling force and the shearing adhesive force at 25 ° C. of the test piece were measured according to JIS Z 0237, and were 0.5 kg / cm and 4.0 kg / cm ² . In addition, when the initial adhesive strength was measured according to JIS Z0237, it was 300 gf / 25 mm.

With respect to the test piece obtained in the same manner as above, 2
After curing at 3 ° C. for 2 weeks, the T-peeling force and the shearing adhesive force at 25 ° C. were measured in the same manner as above, respectively, and were 1.2 kg / cm and 15 kg / cm, respectively.
^{Was 2} .

Example 2 50 g of butyl acrylate
And 50 g of benzyl methacrylate and 50 g of an epoxy resin (trade name: EP4901 manufactured by Asahi Denka Kogyo Co., Ltd.)
0.15 g of a photoradical polymerization initiator (CGI-1700, manufactured by Ciba-Geigy Industries, Ltd.) and a cationic photopolymerization initiator (manufactured by Asahi Denka Kogyo, trade name: Optomer SP-1
70) was stirred and mixed in a separable flask until uniform, and then dissolved oxygen was removed by bubbling with nitrogen gas for 20 minutes to obtain a photopolymerizable composition.

The above photopolymerizable composition was coated on a PET film whose surface was release-treated, and another PET film whose surface was release-treated was further coated thereon. The thickness of the layer was adjusted to be 100 μm.

The laminate obtained as described above was added with 400 n
m, using a fluorescent lamp having a maximum emission wavelength, irradiating near ultraviolet rays substantially containing no light in a wavelength region of less than 360 nm for 15 minutes so that the light intensity becomes 1 mW / cm ^2, and using a PET film. A sandwiched cured adhesive sheet was obtained.

Next, two sets of the above-mentioned curable pressure-sensitive adhesive sheets were prepared, and one of the PET films was peeled off.
Laminated on both sides of a rayon non-woven fabric weighing 18 g / m ² ,
A curable adhesive sheet 1 having a thickness of 200 μm as a whole as shown in FIG. 2 was produced. In FIG. 2, 1a indicates a curable adhesive layer, 3 and 4 indicate PET films, and 5 indicates a rayon nonwoven fabric.

Using the curable pressure-sensitive adhesive sheet obtained as described above, the pressure-sensitive adhesive sheet was pressure-bonded to the adherend in the same manner as in Example 1;
, The T peel strength at 25 ° C., the shear adhesive strength and the initial adhesive strength, and the T peel strength and the shear adhesive strength after curing. The results are shown in Table 1 below.

Comparative Example 1 A curable adhesive sheet was prepared in the same manner as in Example 1 except that no glass cloth was used, and evaluated in the same manner. The results are shown in Table 1 below.
Shown in

Comparative Example 2 Without using a rayon nonwoven fabric,
Except for laminating two curable adhesive sheets,
A curable adhesive sheet laminate was obtained in the same manner as in Example 2,
In the same manner as in Example 2, it was pressed against an adherend and evaluated. The results are shown in Table 1 below.

[0073]

[Table 1]

[0074]

According to the first aspect of the present invention, the curable pressure-sensitive adhesive sheet has a sufficient initial adhesive force at the time of bonding due to the action of the pressure-sensitive adhesive polymer. Irradiation with light cures by polymerization of a compound containing an epoxy group, thereby greatly increasing the adhesive strength. Moreover, since the sheet has the fiber base, the adhesive strength after curing is further enhanced by the action of the fiber base. Therefore, since the adhesive strength can be increased without the need for curing by applying pressure such as pressing, the adhesive can be effectively used for bonding of a joining member that is deformed under pressure bonding conditions.

In the curable adhesive sheet according to the second aspect of the present invention, since the weighing of the fiber base is within the above-mentioned specific range, the effect of improving the bonding strength by having the fiber base is further enhanced. Enhanced.

According to the third aspect of the present invention, after impregnating the fiber base with the photopolymerizable composition, the photoradical polymerization initiator is activated, but the wavelength range of the wavelength range that does not induce ring opening of the epoxy group is induced. Since the adhesive polymer is formed by irradiating light, the contact area between the fiber base material and the curable adhesive is sufficiently large, and the effect of improving the adhesive strength by including the fiber base material is improved. It can be even higher.

According to the fourth aspect of the present invention, the curable pressure-sensitive adhesive sheet according to the present invention, which has excellent adhesive strength, can be efficiently used since the curable pressure-sensitive adhesive layer may be formed and then laminated on the fiber base material. Can be produced well.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a curable adhesive sheet produced in Example 1.

FIG. 2 is a cross-sectional view for explaining a curable adhesive sheet produced in Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Curable adhesive sheet 2 ... Glass cloth 3, 4 ... PET film 5 ... Rayon nonwoven fabric

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 163: 00)

Claims (4)

[Claims] 1. A curable adhesive sheet formed by molding a composition comprising an adhesive polymer, a compound containing an epoxy group, and a compound which is irradiated with light to induce ring opening of the epoxy group. A curable pressure-sensitive adhesive sheet comprising a fiber substrate laminated in or on the sheet. 2. The weighing of the fiber base is from 1.0 to 100.
Curable pressure-sensitive adhesive sheet according to claim 1, characterized in that in the range of 0 g / m ^2. 3. The method for producing a curable pressure-sensitive adhesive sheet according to claim 1 or 2, comprising a monomer for obtaining an adhesive polymer, a photoradical polymerization initiator, and an epoxy group. Impregnating the fiber substrate with a photopolymerizable composition containing a compound to be cured and a compound that is irradiated with light to induce ring opening of the epoxy group; and activating the photoradical polymerization initiator in the photopolymerizable composition. Irradiating light in a wavelength region that does not induce ring opening of the epoxy group to form a tacky polymer. 4. The method for producing a curable pressure-sensitive adhesive sheet according to claim 1, wherein a monomer for obtaining an adhesive polymer, a photo-radical polymerization initiator, and a compound containing an epoxy group. Activating the photoradical polymerization initiator in a photopolymerizable composition containing a compound that is irradiated with light to induce ring opening of an epoxy group, but is irradiated with light in a wavelength region that does not induce ring opening of the epoxy group. Forming a curable adhesive layer by forming a tacky polymer, and laminating the curable adhesive layer to a fiber base material. The method of manufacturing the seat.