JP2017071785A - Adhesive composition and adhesive sheet prepared using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which can bond together a metal and a metal, a metal and an organic material, or an organic material and an organic material, has toughness, and can keep excellent adhesive strength even under a high temperature environment.SOLUTION: An adhesive composition comprises epoxy resin, acrylic resin, and curing agent, the acrylic resin comprising a terpolymer of methyl methacrylate-butyl acrylate-methyl methacrylate or a modified product thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adhesive composition. More specifically, the present invention can bond metals, metals and organic materials, organic materials and organic materials, has toughness, and has excellent adhesive strength even in a high temperature environment. It is related with the adhesive composition which can be hold | maintained, and an adhesive sheet using the same.

Conventionally, as a joining method for integrating two adherends, there are occlusion, welding, and an adhesive method using an adhesive or a pressure-sensitive adhesive, and they are frequently used depending on the application in each field. In recent years, in applications related to transport equipment such as automobiles, as a solution to problems such as the reduction of carbon dioxide CO ₂ emissions in order to prevent global warming, the weight reduction of vehicle bodies and the spread of hybrid cars and electric cars have been promoted. Therefore, there is an increasing tendency to use lightweight aluminum, magnesium, and FRP (CFRP: Carbon Fiber Reinforced Plastics, GFRP: Glass Fiber Reinforced Plastics) for the vehicle body.

  By the way, in the conventional welding method, it is very difficult to weld different materials such as aluminum and iron, and it is impossible to weld the FRP of glass fiber or carbon fiber. Are required to have a welding and identification bond strength. As a bonding method between materials that cannot be bonded by welding or the like, there is a method using an adhesive, but as an adhesive for bonding such a material, metals, metals and organic materials, organic materials and organic materials are used. And that the adhesive strength is strong enough to be used for structural applications, and that the adhesive strength does not deteriorate with temperature changes.

  In general, a thermosetting resin such as an epoxy resin is used as an adhesive that satisfies the above requirements. However, the epoxy adhesive has a high mechanical strength of the resin itself after curing, but is inferior in toughness. When an epoxy adhesive is used for an aircraft, automobile, etc., a decrease in adhesive strength due to brittle fracture becomes a problem. There is a case. In order to solve such problems, attempts have been made to add flexibility to the epoxy adhesive by adding a thermoplastic resin or the like to the epoxy resin (for example, JP-A-2003-82034).

  However, when a thermoplastic resin having flexibility is used for the epoxy adhesive, the heat resistance of the adhesive is impaired, and thus there is a problem that it cannot be used for applications requiring heat resistance.

JP 2003-82034 A

  The present inventors can realize an adhesive having toughness and excellent adhesive strength even in a high temperature environment by adding a specific acrylic resin to an epoxy resin. I got the knowledge. The present invention is based on this finding.

  Therefore, an object of the present invention is to provide an adhesive composition that can bond metals, metal and organic material, organic material and organic material, has toughness, and can maintain excellent adhesive strength even in a high temperature environment. Is to provide.

  Another object of the present invention is to provide an adhesive sheet using the adhesive composition as described above.

The adhesive composition according to the present invention is an adhesive composition comprising an epoxy resin, an acrylic resin, and a curing agent,
The acrylic resin is characterized by comprising a methacrylic-methacrylate-butyl acrylate-methyl methacrylate terpolymer or a modified product thereof.

  Moreover, according to the aspect of this invention, it is preferable that the said epoxy resin is a bisphenol-type epoxy resin.

  Further, according to an aspect of the present invention, the epoxy resin is a bisphenol type epoxy resin that is liquid at room temperature and a bisphenol type epoxy resin that is solid at room temperature and has a glass transition temperature in the range of 50 to 150 ° C. It is preferable to consist of a type epoxy resin.

  Moreover, according to the aspect of this invention, it is preferable that the compounding ratio of the said epoxy resin and the said acrylic resin is 100: 4-100: 20.

  Moreover, according to the aspect of the present invention, it is preferable that the bisphenol-type epoxy resin that is liquid at room temperature and the bisphenol-type epoxy resin that is solid at room temperature are included in a ratio of 100: 300 to 300: 100. .

  Moreover, according to the aspect of this invention, the said epoxy resin may be 140-260 mass parts, the said acrylic resin may be 10-50 mass parts, and the said hardening | curing agent may be 1-30 mass parts. preferable.

  Moreover, according to the aspect of the present invention, it is preferable that the ternary copolymer includes a methyl methacrylate unit and a butyl acrylate unit in a ratio of 1: 1 to 50: 1.

  Moreover, according to the aspect of this invention, it is preferable in the adhesive composition to have a sea-island structure in which the epoxy resin is sea and the acrylic resin is island.

  An adhesive sheet according to another aspect of the present invention is an adhesive sheet obtained by laminating a first release paper, an adhesive layer, and a second release paper in this order, and the adhesive layer is bonded to the adhesive sheet. It comprises an agent composition.

  Moreover, according to the aspect of the present invention, it is preferable that the adhesive layer further includes a core material, and the core material is impregnated with the adhesive.

An adhesion method according to another aspect of the present invention is a method of adhering the first adherend and the second adherend using the adhesive sheet,
From the adhesive sheet, the first release paper and the second release paper are peeled and removed to expose the adhesive layer,
Sandwiching the adhesive layer between the first adherend and the second adherend, and temporarily fixing the first adherend and the second adherend,
The adhesive layer is cured by heating to bond the first adherend and the second adherend.

  Moreover, according to this invention, the bonding body obtained by said adhesion method is also provided.

  According to the present invention, since the specific acrylic resin is added to the epoxy resin, the metal, the metal and the organic material, the organic material and the organic material can be bonded, and the toughness is provided, and the high temperature An adhesive composition that can maintain excellent adhesive strength even in an environment can be realized.

1 is a schematic cross-sectional view according to an embodiment of an adhesive sheet according to the present invention. It is the cross-sectional schematic by the other embodiment of the adhesive sheet by this invention.

  The adhesive composition according to the present invention includes an epoxy resin, an acrylic resin, and a curing agent as essential components. Hereinafter, each component constituting the adhesive composition will be described.

<Epoxy resin>
The epoxy resin used in the adhesive composition according to the present invention means a resin obtained by curing a prepolymer having at least one epoxy group or glycidyl group by a crosslinking polymerization reaction in combination with a curing agent. Such epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, novolac type epoxy resins such as novolac epoxy resin and cresol novolac epoxy resin, biphenyl type epoxy resin, and stilbene type epoxy. Resin, triphenolmethane type epoxy resin, alkyl modified triphenolmethane type epoxy resin, epoxy resin such as triazine nucleus-containing epoxy resin, dicyclopentadiene modified phenol type epoxy resin, phenol novolac resin, cresol novolac resin, Triazines such as bisphenol A novolac resins and other novolac phenolic resins, phenolic resins such as resol phenolic resins, urea (urea) resins and melamine resins Resins having an unsaturated polyester resins, bismaleimide resins, polyurethane resins, diallyl phthalate resins, silicone resins, resins having a benzoxazine ring, cyanate ester resins. Among these epoxy resins, in the present invention, an epoxy resin having a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, or a stilbene skeleton in the main chain is preferable, more preferably a bisphenol type epoxy resin, and particularly preferably a bisphenol A type. It is an epoxy resin.

  The above-described bisphenol A type epoxy resin may be liquid at room temperature or solid at room temperature depending on the number of repeating units of the bisphenol skeleton. A bisphenol A type epoxy resin having a main chain of 1 to 3 is liquid at normal temperature, and a bisphenol A type epoxy resin having a main chain of 2 to 10 is solid at normal temperature. Such a relatively low molecular weight bisphenol A type epoxy resin has crystallinity, and even a solid one that is crystallized at room temperature rapidly melts and changes to a low-viscosity liquid when the temperature reaches the melting point or higher. Therefore, in the step of bonding the adherends, the adhesive adheres to the adherend by heating and solidifies by solidifying the adhesive and the adherend, so that the adhesive strength can be increased. In addition, such a relatively low molecular weight bisphenol A type epoxy resin has a high crosslink density, and therefore has high mechanical strength, good chemical resistance, high curability, and hygroscopicity (because the free volume is small). ) Is also small.

  In the present invention, as the bisphenol A type epoxy resin, it is preferable to use a bisphenol A type epoxy resin that is solid at room temperature and a bisphenol A type epoxy resin that is liquid at room temperature. By using both solid and liquid at room temperature, it is possible to obtain flexibility while maintaining mechanical strength, while maintaining the mechanical strength inherent to the resin (adhesive composition) Flexibility can be obtained. As a result, the bonding strength between adherends can be improved. As the bisphenol A type epoxy resin solid at room temperature, those having a glass transition temperature in the range of 50 to 150 ° C. are preferred from the viewpoint of mechanical strength and heat resistance. Specifically, as a bisphenol A type epoxy resin having a main chain of 1 to 3 which is liquid at normal temperature, JER828 manufactured by Japan Epoxy Resin Co., Ltd. is a bisphenol A type epoxy having a main chain of 2 to 10 which is solid at normal temperature. Examples of the resin include JER1001 manufactured by Japan Epoxy Resin Co., Ltd.

  The blending ratio of the bisphenol A type epoxy resin that is solid at room temperature and the bisphenol A type epoxy resin that is liquid at room temperature depends on the use of the adhesive, but is a ratio of 100: 300 to 300: 100 on a mass basis. It is preferable that it is contained. By setting the blending ratio of both in the above range, an adhesive having better adhesive strength can be obtained.

<Acrylic resin>
As an acrylic resin contained in the adhesive composition according to the present invention, a methyl methacrylate-butyl acrylate-methyl methacrylate terpolymer or a modified product thereof is used. A ternary block copolymer comprising such a methacrylic acid ester polymer block (hereinafter sometimes abbreviated as MMA) and a butyl acrylate polymer block (hereinafter sometimes abbreviated as BA), By adding to the epoxy resin, an adhesive that has toughness and can maintain excellent adhesive strength even in a high temperature environment can be realized. The reason is not clear, but can be estimated as follows.

  In the MMA-BA-MMA terpolymer, the MMA portion is a “hard” segment and the BA portion is a “soft” segment. In conventional adhesives, an acrylic resin has been added to impart toughness (flexibility) to the epoxy resin, but the addition of the acrylic resin reduces the heat resistance of the adhesive itself. Was. If the acrylic resin has both “hard” and “soft” segments as described above, the “hard” segment contributes to heat resistance, and the “soft” segment contributes to toughness and flexibility. It is considered that an adhesive having toughness and capable of maintaining excellent adhesive strength even in a high temperature environment can be realized.

  The above-mentioned MMA-BA-MMA terpolymer can be produced using general living radical polymerization. Among these, from the viewpoint of easy control of the polymerization reaction, it can be suitably produced by primordial transfer radical polymerization. The atom transfer radical polymerization method is a polymerization method using an organic halide or a sulfonyl halide compound as an initiator and a metal complex as a catalyst. When producing a MMA-BA-MMA ternary copolymer by the living radical polymerization method, a method of sequentially adding monomer units, a method of polymerizing the next polymer block using a polymer synthesized in advance as a polymer initiator, Although the method of combining the polymer block polymerized separately by reaction etc. is mentioned, it is preferable to manufacture the ternary copolymer of MMA-BA-MMA by the method by the sequential addition of a monomer unit.

  In the method for producing a MMA-BA-MMA terpolymer by sequential addition of monomer units, the order of addition of the methacrylic acid ester constituting the MMA block and the butyl acrylate constituting the BA block is as follows. There are a method of adding a butyl acrylate monomer after polymerizing a methacrylic acid ester monomer and a method of adding a methacrylic acid ester monomer after first polymerizing a butyl acrylate monomer. The polymerization control is easier when the MMA block is polymerized from the polymerization terminal of the BA block. The ratio of MMA to BA can be controlled by the amount of monomer introduced when the living radical polymerization reaction is performed. The ratio of the MMA block to the BA block in the MMA-BA-MMA terpolymer increases the toughness and flexibility of the adhesive as the ratio of the BA block increases, while the ratio of the MMA block increases. The heat resistance of the adhesive is improved. In the present invention, from the viewpoint of the toughness and heat resistance of the adhesive, the ratio of the MMA block to the BA block is preferably 1: 1 to 50: 1 in the number of monomer units.

  The MMA-BA-MMA terpolymer described above may be a modified product in which a functional group such as carboxylic acid or hydroxyl group is introduced into a part of the BA block. By using such a modified product, the heat resistance is further improved and the compatibility with the above-described epoxy resin is also improved, so that the adhesive strength is further improved.

  When the MMA-BA-MMA terpolymer is added to the epoxy resin, the MMA block part is compatible with the epoxy resin and the BA block part is not compatible with the epoxy resin. Self-organization occurs. As a result, a sea-island structure in which the epoxy resin is the sea and the acrylic resin is the island appears. By exhibiting such a sea-island structure, interface fracture can be avoided and excellent adhesive strength can be maintained.

  In order to express the sea-island structure as described above, an epoxy resin and an acrylic resin (MMA-BA-MMA terpolymer) are blended at a ratio of 100: 4 to 100: 20 on a mass basis. Is preferred. When both are blended in the above ratio, the acrylic resin (island) is dispersed in the form of nano-order fine particles in the epoxy resin (sea).

<Curing agent>
The reaction between the acrylic resin and the epoxy resin proceeds by heating or the like and the adhesive composition is cured, but in the present invention, a curing agent is included in the adhesive composition in order to accelerate the curing reaction. . Examples of the curing agent include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA), diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), diaminodiphenylsulfone ( In addition to aromatic polyamines such as DDS), amine curing agents such as polyamine compounds including dicyandiamide (DICY) and organic acid dihydralazide, and alicyclic rings such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA) Acid anhydride curing agents such as aromatic acid anhydrides such as aromatic acid anhydrides (liquid acid anhydrides), trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenone tetracarboxylic acid (BTDA), Phenolic resin, etc. Phenolic curing agent can be exemplified. In particular, dicyandiamide (DICY) is a latent curing agent, and thus is excellent in storage stability and has a pot life of several weeks even at room temperature storage. Moreover, you may include imidazoles as a hardening accelerator.

  The content of the curing agent in the adhesive composition is 1 to 30 parts by mass when the content of the epoxy resin is 140 to 260 parts by mass and the acrylic resin is 10 to 50 parts by mass. Is preferred. When the blending ratio of the curing agent is less than this range, the heat resistance after joining is low, and the adhesive strength is likely to deteriorate due to temperature change. When the content of the curing agent exceeds this range, when the adhesive sheet is stored until it is bonded to the adherend, the storage stability (pot life) during the storage period decreases, and after the adhesive is cured However, the unreacted curing agent remains, so that there is a problem that the adhesive strength is lowered.

  In addition, the adhesive composition may include, for example, processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slip properties, mold release properties, flame retardancy, antifungal properties. For the purpose of improving and modifying properties, electrical properties, strength, etc., for example, lubricants, plasticizers, fillers, fillers, antistatic agents, antiblocking agents, crosslinking agents, antioxidants, UV absorbers, Light stabilizers, colorants such as dyes and pigments, and the like may be added. Further, if necessary, a coupling agent such as silane, titanium, and aluminum can be further included. Thereby, the adhesiveness between the resin, the adherend, and the resin and the core material to be described later can be improved.

  The adhesive composition used in the present invention can be prepared by mixing the above-described components and kneading and dispersing as necessary. The mixing or dispersing method is not particularly limited, and a conventional kneading and dispersing machine such as a two-roll mill, a three-roll mill, a pebble mill, a tron mill, a Szegvari attritor, a high-speed impeller disperser, a high-speed stone mill, A high speed impact mill, a desper, a high speed mixer, a ribbon blender, a kneader, an intensive mixer, a tumbler, a blender, a desperser, a homogenizer, an ultrasonic disperser, and the like can be applied. When multiple types are used as the hard epoxy resin, these are first mixed and stirred, then the curing agent is mixed and stirred, diluted with a solvent, and then the soft epoxy resin is mixed and stirred, and then the acrylic resin Are preferably mixed and stirred.

<Adhesive sheet>
As shown in FIG. 1, the adhesive sheet according to the present invention has a layer structure in which a first release paper and a second release paper are provided on both surfaces of an adhesive layer made of the above adhesive composition. In the present specification, the first release paper 21A and the second release paper 21B are collectively referred to as release paper 21. As shown in FIG. 2, the adhesive layer further includes a core material, and the core material may be impregnated with the adhesive. The core material is preferably a woven fabric or a non-woven fabric, and various conventionally known woven or non-woven fabrics can be used. Examples thereof include heat-resistant plastic fibers such as liquid crystal polymers, glass fibers, aramid fibers, and carbon fibers. A woven fabric and a non-woven fabric composed of these can be used.

  When the adhesive layer includes a core material, a first release paper 21 (described later) and the core material 15 are overlapped and run using a coating machine, and the above-described adhesive 13 composition is applied to the surface of the core material 15. Thus, since the core material 15 is impregnated, the second release paper 21B is bonded to the coated surface after drying, whereby the adhesive sheet 1 is obtained.

  The method for applying the adhesive composition to the release paper is not particularly limited. For example, roll coating, reverse roll coating, transfer roll coating, gravure coating, gravure reverse coating, comma coating, rod coat, blade Coating, bar coating, wire bar coating, die coating, lip coating, dip coating, etc. can be applied. After the composition is applied to the release surface of the first release paper 21A or the first release paper 21A and the core material 15 by the coating method described above and dried, the second release paper is applied. The pattern paper 21B may be attached. The viscosity of the composition (coating solution) is adjusted to about 1 to 20000 centistokes (25 ° C.), preferably 1 to 2000 centistokes. In the case of impregnating and applying to the core material 15, a lower viscosity is preferable, and it is 1-1000 centistokes.

  The first release paper 21A and the second release paper 21B may be the same or different. As the release paper 21, conventionally known ones such as a release film, a separate paper, a separate film, a separate paper, a release film, and a release paper can be suitably used. Moreover, you may use what formed the release layer in the single side | surface or both surfaces of base materials for release paper, such as quality paper, a coated paper, an impregnation paper, and a plastic film. The release layer is not particularly limited as long as it is a material having releasability. For example, silicone resin, organic resin-modified silicone resin, fluororesin, aminoalkyd resin, melamine resin, acrylic resin, polyester resin, etc. There is. These resins can be used in any of emulsion type, solvent type and solventless type.

  The release layer is formed by applying a coating liquid in which a release layer component is dispersed and / or dissolved on one side of a release paper base film, followed by heat drying and / or curing. As a coating method of the coating liquid, a known and arbitrary coating method can be applied, for example, roll coating, gravure coating, spray coating and the like. Moreover, you may form a release layer in the whole surface or a part of at least single side | surface of a base film as needed.

  The peeling force of the first and second release papers is preferably about 1 to 2000 mN / cm, and more preferably 100 to 1000 mN / cm with respect to the adhesive sheet. When the release force of the release layer is less than 1 mN / cm, the release force from the adhesive sheet or the adherend is weak, and it peels off or partially floats. Moreover, when larger than 2000 mN / cm, the peeling force of a release layer is strong and it is hard to peel. From the viewpoint of stable releasability and processability, addition and / or polycondensation-type curable silicone resins for release paper, which are mainly composed of polydimethylsiloxane, are preferred.

<Adhesion method of adherend>
In the bonding with the adherend, the first release paper 21A and the second release paper 21B of the adhesive sheet 1 are peeled off and the adhesive layer 11 is exposed. The exposed adhesive layer 11 is sandwiched between two identical or different first adherends and second adherends and held with the adhesiveness of the adhesive layer 11. Next, the adhesive layer 11 can be cured by heating or pressurizing to firmly bond the first adherend and the second adherend. As described above, by using the adhesive sheet according to the present invention, the adherends can be temporarily fixed using the initial tackiness, and then the adhesive sheet is thermally cured by, for example, a batch method. Therefore, the process such as preheating can be omitted and the productivity is remarkably improved.

  The adherend is not particularly limited, and examples thereof include metals, inorganic materials, organic materials, composite materials combining these materials, and laminated materials.

The heating temperature at the time of curing is about 60 ° C to 250 ° C, preferably 100 ° C to 180 ° C.
The heating time is 1 to 240 minutes, preferably 10 to 120 minutes. Since the adhesive layer 11 of the cured adhesive sheet 1 has initial tackiness, there is no preheating process, and the work can be performed while holding the adherend with only the tackiness, so that the workability is good and the cost is low. Moreover, by selecting the material of the adhesive layer and the blending ratio thereof, the metals, the metal and the organic material, and the organic material and the organic material can be bonded. Furthermore, strong adhesive strength resulting from the epoxy resin is obtained, and this adhesive strength is not easily deteriorated even by temperature change, and because it is attributed to the acrylic resin, the brittleness is low, and excellent shear strength and high resistance to resistance are obtained. Since it has impact and heat resistance, it can be used for structural purposes.

<Bonded body>
By using the adhesive sheet according to the present invention, it is possible to strongly bond materials (adherents) such as FRP of glass fiber and carbon fiber, different metals, which are difficult with conventional welding methods. For example, metals such as aluminum and iron And a bonded body of FRP and CFRP can be obtained.
These bonded bodies can maintain excellent adhesive strength without undergoing temperature change, have low brittleness, and have excellent shear strength, high impact resistance, and heat resistance. However, the present invention can be used in the fields of electronic devices, electronic device casings, home appliances, infrastructure structures, lifeline building materials, general building materials, and the like.

  Examples The present invention will be described in more detail with reference to examples, but the present invention is not limited to the contents of these examples. In addition, each composition of each layer is the mass part of solid content except a solvent.

Examples 1-14 and Comparative Examples 1-5
<Preparation of adhesive composition>
According to the composition shown in Table 1 below, an adhesive was prepared by adding a curing agent to a bisphenol A type epoxy resin and mixing with a stirrer, and then adding and mixing an acrylic resin to the mixture. In Table 1 below,
JER828, JER1001 and JER1009 are bisphenol A type epoxy resins manufactured by Mitsubishi Chemical Corporation.
W-197C is an ethyl acrylate-methyl methacrylate copolymer manufactured by Negami Kogyo Co., Ltd.
SK Dyne 1495 is an acrylic-vinyl acetate copolymer manufactured by Soken Chemical Co., Ltd.
LC # 6500 is a polymethyl methacrylate manufactured by Toei Kasei Co., Ltd.
SM4032XM10 is a modified methyl methacrylate-butyl acrylate-methyl methacrylate ternary copolymer having a carboxyl group introduced by Arkema,
M22 is a terpolymer of methyl methacrylate-butyl acrylate-methyl methacrylate manufactured by Arkema,
M22N is a modified methyl methacrylate-butyl acrylate-methyl methacrylate ternary copolymer having a hydroxyl group introduced by Arkema,
KBM-403 is a silane coupling agent manufactured by Shin-Etsu Silicone,
DICY7 is a dicyandiamit manufactured by Mitsubishi Chemical Corporation.
HIPA-2E4MZ is clathrate imidazole manufactured by Nippon Soda Co., Ltd.
Amicure MY-H and Amicure PN-50 are amine adducts manufactured by Ajinomoto Fine Techno Co., Ltd.
FXR-1030 represents the urea adduct made from Ajinomoto Fine Techno Co., respectively.

<Preparation of adhesive sheet>
On the surface of the core material (Veculus MBBK6FZSO, manufactured by Kuraray Co., Ltd.) obtained by superimposing the obtained adhesive on a separator film (SP-PET 03BU, manufactured by Tosero Co., Ltd.), a coating amount is 100 g / m ² with a comma coater. The adhesive sheet was impregnated into the core material to form an adhesive layer, and a separate film (SP-PET 01BU, manufactured by Tosero Corp.) was bonded onto the adhesive layer to prepare an adhesive sheet. .

<Production of bonded body>
The obtained adhesive sheet was cut into 25 mm × 12.5 mm, one of the separator films was peeled off to expose the adhesive layer, and one of the adherends CFRP (length 100 mm × width 25 mm × thickness 1.5 mm) ). The separator film is peeled off from the adhesive sheet attached to the CFRP to expose the adhesive layer, and the end of the other adherend CFRP (length 100 mm × width 25 mm × thickness 1.5 mm) is formed on the adhesive layer portion. The part was pasted.

  Next, a bonded body was obtained by applying a load of 3 kg on the temporarily fixed adherend and heat-curing the adhesive layer at 130 ° C. for 2 hours.

<Evaluation of adhesive strength>
About each obtained bonding body, the adhesive strength in each environment of room temperature (25 degreeC) and 80 degreeC was evaluated. Both ends of the sample obtained above were fixed to Tensilon (Orientec RTA-1T), pulled at 1 mm / min, and measured for shear strength. The evaluation results were as shown in Table 2 below.

<Evaluation of film forming property>
An adhesive is applied to a Sepa film (SP-PET 01BU, manufactured by Tosero Co., Ltd.) with a comma coater so that the coating amount after drying is 50 g / m ^2, and dried at 100 ° C. for 3 minutes. The appearance of was observed. The evaluation criteria were as follows.
◯: The coating film has a uniform thickness (± 5 μm). X: There is a portion where the adhesive is repelled on the surface of the separator film and the evaluation result is as shown in Table 2 below.

1: Adhesive sheet 11: Adhesive layer 13: Adhesive 15: Core material 21: Release paper 21A: First release paper 21B: Second release paper

The adhesive composition according to the invention, epoxy resin, an adhesive composition comprising an acrylic resin, and a curing agent,
The acrylic resin contains a copolymer of methyl methacrylate and butyl acrylate, or a modified product thereof .

The adhesive sheet according to another aspect of the present invention includes a first release paper, an adhesive layer, and a second release paper, an adhesive sheet that has been stacked in this order, wherein the adhesive layer, the adhesive adhesive composition is including ones.

Further, according to the aspect of the present invention, the adhesive layer is further seen contains a core material, it is preferable that the adhesive composition is impregnated in the core material.

Moreover, according to this invention, the bonding body by which the 1st to-be-adhered body and the 2nd to-be-adhered body were bonded via the hardened | cured material of the said adhesive composition is also provided.

Claims (12)

An adhesive composition comprising an epoxy resin, an acrylic resin, and a curing agent,
The adhesive composition according to claim 1, wherein the acrylic resin comprises a terpolymer of methyl methacrylate-butyl acrylate-methyl methacrylate or a modified product thereof.   The adhesive composition according to claim 1, wherein the epoxy resin is a bisphenol type epoxy resin.   The said epoxy resin consists of two types of bisphenol type epoxy resins, a bisphenol type epoxy resin that is liquid at room temperature and a bisphenol type epoxy resin that is solid at room temperature and has a glass transition temperature in the range of 50 to 150 ° C. The adhesive composition according to 2.   The adhesive composition according to any one of claims 1 to 3, wherein a blending ratio of the epoxy resin and the acrylic resin is 100: 4 to 100: 20.   The adhesive composition according to claim 3, wherein the bisphenol-type epoxy resin that is liquid at room temperature and the bisphenol-type epoxy resin that is solid at room temperature are contained in a ratio of 100: 300 to 300: 100.   The epoxy resin is 140 to 260 parts by mass, the acrylic resin is 10 to 50 parts by mass, and the curing agent is 1 to 30 parts by mass, according to any one of claims 1 to 5. The adhesive composition as described.   The adhesive composition according to any one of claims 1 to 7, wherein the ternary copolymer contains methyl methacrylate units and butyl acrylate units in a ratio of 1: 1 to 50: 1.   The adhesive composition according to any one of claims 1 to 7, wherein the adhesive composition has a sea-island structure in which the epoxy resin is sea and the acrylic resin is island.   It is an adhesive sheet formed by laminating a first release paper, an adhesive layer, and a second release paper in this order, and the adhesive layer is the adhesive according to any one of claims 1 to 8. An adhesive sheet comprising the composition.   The adhesive sheet according to claim 9, wherein the adhesive layer further comprises a core material, and the core material is impregnated with the adhesive. A method for adhering a first adherend and a second adherend using the adhesive sheet according to claim 9 or 10,
From the adhesive sheet, the first release paper and the second release paper are peeled and removed to expose the adhesive layer,
Sandwiching the adhesive layer between the first adherend and the second adherend, and temporarily fixing the first adherend and the second adherend,
The method comprising: curing the adhesive layer by heating to bond the first adherend and the second adherend.   The bonding body obtained by the method of Claim 11.

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