JP6801189B2 - Article manufacturing method and adhesive - Google Patents

Description

The present invention relates to a method for producing an article and an adhesive used therein.

Conventionally, in the manufacturing process of an article, various adhesives have been used to bond each member constituting the article. As such an adhesive, for example, an epoxy resin adhesive mainly containing an epoxy resin is known, and among the epoxy resin adhesives, a one-component type in which the reaction is started by oxygen or moisture in the air. Originally, there is a two-component type in which the reaction is started by mixing a curing agent with an epoxy resin.

By the way, as shown in Patent Document 1, for example, the one-component epoxy resin adhesive is stored in a state where a curing agent is mixed with an epoxy resin as a main agent. Therefore, in the case of a one-component epoxy resin adhesive, it is required to maintain a good pot life. Specifically, there is a demand for a one-component epoxy resin adhesive capable of suppressing the progress of the reaction between the epoxy resin and the curing agent in an environment at room temperature.

As such a one-component epoxy resin adhesive, for example, an adhesive in which an epoxy resin is mixed with a curing agent that starts a reaction under a high temperature condition of 250 ° C. or higher has been proposed. By using a curing agent that starts the reaction under high temperature conditions, the progress of the reaction with the epoxy resin can be suppressed in an environment at room temperature, and the pot life can be kept good.

Further, conventionally, from the viewpoint of simplifying the manufacturing process of an article using an adhesive, it has been required to use a sheet-shaped adhesive. Since the adhesive is in the form of a sheet, it is possible to suppress the occurrence of problems such as unevenness of the adhesive and the spread of the adhesive to an unexpected region.

Japanese Unexamined Patent Publication No. 2010-195998

In order to suppress the progress of the reaction in a normal temperature environment and maintain a good pot life, it is necessary to use a curing agent that starts the reaction in a high temperature environment as described above. However, when an adhesive is used in the manufacturing process of an article, an adhesive that reacts in an environment of 200 ° C. or lower is required in order to improve workability and shorten the tact time. However, in the case of a one-component epoxy resin adhesive that uses a curing agent that starts the reaction in an environment of 200 ° C or lower, it is difficult to suppress the progress of the reaction in an environment of normal temperature, and the temperature is lower than normal temperature. It is necessary to save it in the environment of. When storage in a low temperature environment is required, there is a problem that temperature control becomes troublesome, for example, a facility for cooling and storing the adhesive is required at a work site.

As described above, conventionally, when a curing agent that starts a reaction in an environment of 200 ° C. or lower is used as a one-component epoxy resin adhesive to improve workability and shorten tact time. It is difficult to maintain a good pot life by suppressing the progress of the reaction in a normal temperature environment. That is, it is difficult to adjust the curing temperature at which the reaction is started by the curing agent to 200 ° C. or lower and to maintain a good pot life. As a method for solving such a problem, for example, Patent Document 1 proposes a method of using a latent curing agent in which a curing agent is covered with an inclusion material, but the curing agent is stained from the inclusion material. There is a problem that it is put out and a sufficient pot life cannot be obtained.

The present invention has been made in view of the above problems, and manufacture of an article using an adhesive capable of lowering the curing temperature at which the reaction is started by a curing agent to 200 ° C. or lower while maintaining a good pot life. The main purpose is to provide a method.

In order to solve the above problems, the present invention has an adhesive step of arranging a sheet-shaped adhesive on a member or between two of the members and curing the adhesive at a temperature of 200 ° C. or lower. The adhesive is a one-component epoxy resin adhesive, and further, the adhesive is sheared 28 days after the start of storage when the adhesive is subjected to a storage test under a temperature condition of 40 ° C. Provided is a method for producing an article, characterized in that the strength is an adhesive that maintains the shear strength at the start of storage.

According to the present invention, when the storage test as described above is performed, the epoxy resin and the curing are performed in a normal temperature environment by using an adhesive capable of maintaining the shear strength for a certain period from the start of storage. A good pot life can be maintained by suppressing the progress of the reaction of the agent, and the curing temperature of the adhesive in the bonding process can be set to 200 ° C. or lower, so that the workability in the production of the article can be improved and the tact time can be reduced. It is possible to shorten the time.

The present invention also provides an adhesive containing an epoxy resin and a curing agent, wherein the curing agent has a structure represented by the following general formula (1).

(In the above formula (1), R ¹ and R ² are -CH _2- OH or -H. However, at least one of R ¹ and R ² is -CH _2- OH.)

According to the present invention, by using a curing agent having a predetermined structure, it is possible to suppress the progress of the reaction with the epoxy resin and maintain a good pot life in an environment at room temperature, and the curing temperature of the adhesive. Can be 200 ° C. or lower.

In the present invention, it is preferably in the form of a sheet containing an acrylic resin. Since the adhesive contains an acrylic resin and is in the form of a sheet, the adhesive of the present invention can be easily used.

According to the present invention, the progress of the reaction between the epoxy resin and the curing agent can be suppressed to maintain a good pot life in an environment at room temperature, and the curing temperature at which the reaction is started by the curing agent can be set to 200 ° C. or lower. It has the effect of being able to provide a method of manufacturing an article using a possible adhesive.

It is a schematic process diagram which shows an example of the manufacturing method of the article of this invention. It is a schematic process diagram which shows another example of the manufacturing method of the article of this invention. It is the schematic sectional drawing which shows an example of the adhesive sheet in this invention. It is the schematic sectional drawing which shows the other example of the adhesive sheet in this invention.

Hereinafter, the method for producing the article of the present invention and the adhesive will be described in detail.

A. Method for Manufacturing Articles The method for manufacturing articles of the present invention includes an bonding step in which a sheet-shaped adhesive is placed on a member or between two of the above members, and the adhesive is cured at a temperature of 200 ° C. or lower. The adhesive is a one-component epoxy resin adhesive, and the adhesive is 28 days after the start of storage when the adhesive is subjected to a storage test under a temperature condition of 40 ° C. The method is characterized in that the shear strength is an adhesive that maintains the shear strength at the start of storage.

A method for producing such an article of the present invention will be described with reference to the drawings.
1 (a) to 1 (c) are schematic process diagrams showing an example of a method for producing an article of the present invention. In the method for producing an article of the present invention, as shown in FIG. 1A, a sheet-shaped adhesive 1 is arranged on a member 2, and as shown in FIG. 1B, a sheet is placed at a temperature of 200 ° C. or lower. It has an adhesive step of curing the shape-like adhesive 1. As a result, the sheet-shaped adhesive becomes the adhesive layer 1'as shown in FIG. 1 (c), and the article 10 can be obtained. The adhesive used at this time is an adhesive whose shear strength 28 days after the start of storage maintains the shear strength at the start of storage when the adhesive is subjected to a storage test under a temperature condition of 40 ° C. It is characterized by being.

2 (a) to 2 (c) are schematic process diagrams showing other examples of the method for producing the article of the present invention. In the method for producing an article of the present invention, as shown in FIG. 2A, a sheet-shaped adhesive 1 is arranged between two members 2a and 2b, and as shown in FIG. 2B, the temperature is 200 ° C. It has an bonding step of curing the sheet-shaped adhesive 1 at the following temperature. As a result, the sheet-shaped adhesive becomes the adhesive layer 1'as shown in FIG. 2C, and the article 10 can be obtained. The adhesive used at this time is an adhesive whose shear strength 28 days after the start of storage maintains the shear strength at the start of storage when the adhesive is subjected to a storage test under a temperature condition of 40 ° C. It is characterized by being.

Here, the "one-component epoxy resin adhesive" is an adhesive in which a liquid adhesive containing an epoxy resin and a curing agent is cured by heating to become a cured product. Further, the "epoxy resin" refers to a resin having at least one epoxy group or a glycidyl group. Since the specific epoxy resin used in the present invention will be described later, the description here will be omitted.

Furthermore, "when the adhesive is subjected to a storage test under a temperature condition of 40 ° C., the shear strength 28 days after the start of storage maintains the shear strength at the start of storage" is described in Examples described later. In the shear test performed in Comparative Examples 1 to 3, the shear strength 28 days after the start of storage means that the shear strength at the start of storage is maintained. Here, "maintaining the shear strength" means not only when the shear strength is completely the same at the start of storage and 28 days after the start of storage, but also when the shear strength 28 days after the start of storage starts storage. This includes cases where the shear strength is 80% or more. Above all, in the present invention, the shear strength 28 days after the start of storage is preferably 90% or more, and particularly preferably 95% or more of the shear strength at the start of storage.

Further, the "article" is obtained by arranging an adhesive on a member or between two members, curing and adhering the adhesive, and is not limited to the fields of automobiles, aircrafts, ships and the like. , Electronic devices, electronic device housings, home appliances, infrastructure structures, lifeline building materials, general building materials, etc.

According to the present invention, the following effects can be obtained.
First, in order to suppress the progress of the reaction in a normal temperature environment and maintain a good pot life, a curing agent that does not start the reaction in a normal temperature environment but starts the reaction in a high temperature (250 ° C or higher) environment is used. Need to use. However, when an adhesive is used in the manufacturing process of an article, in order to improve workability and shorten the tact time, use an adhesive that starts the reaction at least in an environment of 200 ° C. or lower, not in a high temperature environment. Is required. On the other hand, in the case of a one-component epoxy resin adhesive using a curing agent that starts the reaction in an environment of 200 ° C. or lower, it becomes difficult to suppress the progress of the reaction in an environment of normal temperature, and the temperature is lower than normal temperature. It is necessary to save it in the environment of. When storage in a low temperature environment is required, there is a problem that temperature control becomes troublesome, for example, a facility for cooling and storing the adhesive is required at a work site.

On the other hand, in the present invention, when the storage test as described above is performed, the epoxy resin is used in an environment at room temperature by using an adhesive capable of maintaining the shear strength for a certain period from the start of storage. In addition to being able to suppress the progress of the reaction of the curing agent and maintain a good pot life, the curing temperature of the adhesive in the bonding process can be set to 200 ° C or less, which improves workability and tact in the manufacture of articles. It is possible to shorten the time.

Hereinafter, the method for producing the article of the present invention will be described in detail.

The method for producing an article of the present invention is a method having at least an bonding step.
The bonding step in the present invention is a step of arranging a sheet-shaped adhesive on a member or between the two members and curing the adhesive at a temperature of 200 ° C. or lower. That is, in the present invention, the sheet-shaped adhesive can be cured into an adhesive layer by the bonding step.

In the bonding step of the present invention, the method of curing the sheet-shaped adhesive arranged on the member or between the two members is not particularly limited as long as it is a method of curing at a temperature of 200 ° C. or lower. By being able to cure at a temperature of 200 ° C. or lower, it is possible to improve workability and shorten the tact time when manufacturing an article. In the present invention, the sheet-shaped adhesive is preferably cured at a temperature of 180 ° C. or lower, and particularly preferably at a temperature of 150 ° C. or lower. Further, in the present invention, the sheet-shaped adhesive can be cured at a temperature of 80 ° C. or higher.

In the bonding step of the present invention, the curing time for curing the sheet-shaped adhesive may be such that the sheet-shaped adhesive can be cured to form an adhesive layer, and the curing temperature and adhesion described above may be sufficient. It can be appropriately adjusted according to the type of the agent and the like. In the present invention, for example, the curing time is preferably in the range of 10 min to 60 min, and particularly preferably in the range of 15 min to 30 min.

In the bonding step of the present invention, the thickness of the adhesive layer obtained by curing the sheet-shaped adhesive on the member or between the two members is appropriately adjusted according to the article to be obtained by the present invention. It is possible, but is not particularly limited, but for example, it is preferably in the range of 50 μm to 1000 μm, and particularly preferably in the range of 50 μm to 300 μm.

Hereinafter, the sheet-shaped adhesive and members used in the present invention will be described.

1. 1. Sheet-shaped adhesive The sheet-shaped adhesive in the present invention will be described with reference to the drawings. Hereinafter, the sheet-shaped adhesive may be referred to as an adhesive sheet.

FIG. 3 is a schematic cross-sectional view showing an example of the adhesive sheet in the present invention. As shown in FIG. 3, in the adhesive sheet 20 of the present invention, the adhesive composition 1 ”is arranged between the first release paper 3a and the second release paper 3b to remove the solvent (hereinafter, when it is dried). It can be obtained by doing.

Further, FIG. 4 is a schematic cross-sectional view showing another example of the adhesive sheet in the present invention. As shown in FIG. 4, the adhesive sheet 20 in the present invention may be impregnated with the adhesive composition 1'in the core material 4. The reference numerals not described in FIG. 4 can be the same as those in FIG. 3, and thus the description thereof will be omitted here.

The adhesive sheet in the present invention is obtained by arranging and drying the adhesive composition. That is, the adhesive sheet is in a state in which the solvent contained in the adhesive composition is removed by drying the adhesive composition.

Hereinafter, the adhesive composition constituting the adhesive sheet in the present invention, the method for producing the adhesive sheet, and the adhesive method using the adhesive sheet will be described.

(1) Adhesive Composition The adhesive composition used in the present invention is a material constituting an adhesive sheet.
Hereinafter, the materials contained in the adhesive composition will be described.

(A) Epoxy resin The epoxy resin used in the present invention is not particularly limited as long as it is a material that cures by causing a cross-linking polymerization reaction when used in combination with a curing agent. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin and other bisphenol type epoxy resin, novolac epoxy resin, cresol novolac epoxy resin and other novolac type epoxy resin, biphenyl type epoxy resin, and stillben type epoxy resin. Examples thereof include triphenol methane type epoxy resin, alkyl modified triphenol methane type epoxy resin, triazine nucleus containing epoxy resin, dicyclopentadiene modified phenol type epoxy resin and other epoxy resins, and phenol novolac resin, cresol novolac resin, bisphenol A. Novolac type phenol resin such as novolak resin, phenol resin such as resolephenol resin, resin having triazine ring such as urea (urea) resin, melamine resin, unsaturated polyester resin, bismaleimide resin, polyurethane resin, diallyl phthalate resin, silicon Examples thereof include a resin, a resin having a benzoxazine ring, and a cyanate ester resin. Among them, in the present invention, it is preferable to use an epoxy resin having a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, or a stillben skeleton as a main chain, and in particular, a bisphenol type epoxy resin is preferably used, and among them, a bisphenol A type epoxy. It is preferable to use a resin.

The bisphenol A type epoxy resin can exist in a liquid state at room temperature or in a solid state at room temperature, depending on the number of repeating units of the bisphenol skeleton. The bisphenol A type epoxy resin having a main chain of 1 to 3 is liquid at room temperature, and the bisphenol A type epoxy resin having a main chain of 2 to 10 is solid at room temperature. Such a relatively low molecular weight bisphenol A type epoxy resin has crystallinity, and even a solid one that crystallizes at room temperature rapidly melts and changes to a low-viscosity liquid at a temperature equal to or higher than the melting point. Therefore, when a bisphenol A type epoxy resin is used as the epoxy resin constituting the adhesive, the adhesive is adhered and solidified on the member or between the two members in the bonding step, and the adhesive and the member are separated from each other. It can be firmly adhered and the adhesive strength can be increased. Further, such a bisphenol A type epoxy resin having a relatively low molecular weight has a high crosslink density, so that it has high mechanical strength, good chemical resistance, high curability, and a small free volume, so that it has hygroscopicity. It has the characteristic of becoming smaller.

In the present invention, as the bisphenol A type epoxy resin, it is preferable to use the above-mentioned bisphenol A type epoxy resin that is solid at room temperature and the bisphenol A type epoxy resin that is liquid at room temperature in combination. By using both solid and liquid materials at room temperature, flexibility can be obtained while maintaining mechanical strength. As a result, the joint strength with the member can be improved. The bisphenol A type epoxy resin that is solid at room temperature is preferably a material having a glass transition temperature in the range of 50 ° C. to 150 ° C. from the viewpoint of mechanical strength and heat resistance. Specifically, examples of the bisphenol A type epoxy resin having a main chain of 1 to 3 which is liquid at room temperature include JER828 manufactured by Mitsubishi Resin Co., Ltd., and bisphenol A having a main chain of 2 to 10 which is solid at room temperature. Examples of the type epoxy resin include JER1009 manufactured by Mitsubishi Resin Co., Ltd.

The blending ratio of the bisphenol A type epoxy resin solid at room temperature and the bisphenol A type epoxy resin liquid at room temperature can be appropriately adjusted according to the type of the article obtained by the present invention, but for example, in terms of mass. , 100: 300 to 300: 100 is preferable. By setting the blending ratio of both in the above range, an adhesive having more excellent adhesive strength can be obtained.

(B) Curing Agent The curing agent used in the present invention may be any material that can be cured by causing a cross-linking polymerization reaction at a temperature of 200 ° C. or lower when used in combination with the above-mentioned epoxy resin. Further, when the adhesive is subjected to a storage test under a temperature condition of 40 ° C., the shear strength 28 days after the start of storage may be any material that can maintain the shear strength at the start of storage. That is, the curing agent used in the present invention can suppress the progress of the reaction with the epoxy resin to maintain a good pot life in an environment at room temperature, and the curing temperature at which the reaction with the epoxy resin is started is 200. Any curing agent that can keep the temperature below ° C. may be used.

Examples of such a curing agent include an imidazole-based curing agent having an imidazole ring and having at least a hydroxyl group. Specific examples thereof include a curing agent having a structure represented by the following general (1).

(In the above formula (1), R ¹ and R ² are -CH _2- OH or -H. However, at least one of R ¹ and R ² is -CH _2- OH.)

Examples of the curing agent represented by the general formula (1) include the following compounds (1-1) to (1-3). In the present invention, it is preferable to use compound (1-1).

The content of the curing agent used in the present invention in the adhesive composition can be appropriately adjusted according to the content of the epoxy resin, and is not particularly limited. For example, with respect to one equivalent of epoxy groups in the epoxy resin. It is preferably in the range of 5 parts by weight to 20 parts by weight, and more preferably in the range of 10 parts by weight to 15 parts by weight. Specifically, when the content of the epoxy resin is 140 parts by mass to 260 parts by mass and the content of the acrylic resin described later is 10 parts by mass to 50 parts by mass, it is 1 part by mass to 30 parts by mass. It can be within the range. When the content of the curing agent is within the above range, the adhesive strength after the bonding step can be sufficiently maintained, and a better pot life can be maintained.

(C) Acrylic Resin The adhesive composition used in the present invention usually contains an acrylic resin in addition to the above-mentioned epoxy resin and curing agent. By containing the acrylic resin, the dried adhesive composition can be made into a sheet.
The "acrylic resin" here is the same as a general acrylic resin.

The acrylic resin used in the present invention may be any material as long as it can form the desired adhesive sheet in the present invention, and the acrylic resin used for general adhesives can be used. For example, an acrylic acid ester copolymer can be used. The monomer components of the acrylic acid ester copolymer include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, isobutyl acrylate, n-hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and acrylate. Acrylic acid ester monomers such as lauryl; maleic acid, itaconic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylamide, N-methylol acrylamide, n-butoxy-N-methylol acrylamide, 2-acrylamide-2- Functional group-containing monomers such as sodium methyl-1-propanesulfonate, diacetoneacrylamide, and glycidyl acrylate; monomers such as styrene, vinyltoluene, vinyl acetate, acrylonitrile, vinyl chloride, vinylidene chloride, and ethyl vinyl ether; and the like can be mentioned. The acrylic acid ester copolymer is a copolymer of these monomer components.

Among these monomer components, an acrylic acid ester copolymer containing a compound having an epoxy group, a hydroxyl group, a carboxyl group, a nitrile group or the like as a functional group as a monomer component is preferable. Specific examples thereof include ethyl acrylate-butyl acrylate-acrylonitrile copolymer, ethyl acrylate-acrylonitrile copolymer, butyl acrylate-acrylonitrile copolymer and the like. By using such an acrylic resin, it is possible to improve the adhesiveness to the member.
The "acrylic acid" such as methyl acrylate and ethyl acrylate here also includes "methacrylic acid" such as methyl methacrylate and ethyl methacrylate.

Moreover, as an acrylic acid ester copolymer, for example, a block copolymer can be mentioned. Of these, triblock copolymers containing methacrylate-acrylate-methacrylate are preferable. Examples of the methacrylate constituting the triblock copolymer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzidyl methacrylate and the like. Be done. Examples of the acrylate constituting the triblock copolymer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, and benzidyl acrylate. Can be mentioned. Specific examples of the triblock copolymer composed of methacrylate-acrylate-methacrylate include methyl methacrylate-butyl acrylate-methyl methacrylate triblock copolymer. Such a block copolymer is preferable from the viewpoint of exhibiting sufficient adhesiveness to a member to be an adherend and improving heat resistance.

Above all, in the present invention, a ternary copolymer of methyl methacrylate-butyl acrylate-methyl methacrylate or a modified product thereof is used. A ternary block copolymer composed of such a metaacrylic acid ester polymer block (hereinafter, may be abbreviated as MMA) and a butyl acrylate polymer block (hereinafter, may be abbreviated as BA) is described above. By adding it to the epoxy resin, it is possible to realize an adhesive having toughness and capable of maintaining excellent adhesive strength even in a high temperature environment. The reason is not clear, but the following can be presumed.

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

The ternary copolymer of MMA-BA-MMA can be produced by using general living radical polymerization. Of these, from the viewpoint of ease of control of the polymerization reaction, it can be suitably produced by primitive mobile 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 ternary copolymer of MMA-BA-MMA by the living radical polymerization method, a method of sequentially adding monomer units, a method of polymerizing the next polymer block using a pre-synthesized polymer as a polymer initiator, Examples thereof include a method of bonding polymer blocks polymerized separately by a reaction, but it is preferable to produce a ternary copolymer of MMA-BA-MMA by a method of sequentially adding monomer units.

The ternary copolymer of MMA-BA-MMA may be a modified product in which a functional group such as a carboxylic acid or a 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-mentioned epoxy resin is also improved, so that the adhesive strength is further improved.

When the MMA-BA-MMA ternary copolymer is added to the epoki resin, the MMA block portion is compatible with the epoxy resin and the BA block portion is not compatible with the epoxy resin, so that self-assembly using the epoxy resin as a matrix occurs. .. As a result, a sea-island structure in which the epoxy resin is the sea and the acrylic resin is the island is developed. By developing such a sea-island structure, interfacial fracture can be avoided and excellent adhesive strength can be maintained.

In order to develop the sea-island structure as described above, an epoxy resin and an acrylic resin (MMA-BA-MMA ternary copolymer) may be blended at a ratio of 100: 4 to 100:20 on a mass basis. preferable. When both are mixed in such a ratio, the acrylic resin (islands) is dispersed in the epoxy resin (sea) in the form of nano-order level fine particles.

(D) Solvent The adhesive composition used in the present invention usually contains a solvent at the time of production, but the solvent is volatilized and removed when the adhesive composition is dried to form an adhesive sheet. The solvent used in the present invention may be any material used in a general adhesive composition, and is not particularly limited. For example, toluene, methyl ethyl ketone (MEK), ethyl acetate, dimethylacetamide, N-methyl-2. -Pyrrolidone and the like can be mentioned. Further, the content of the solvent contained in the adhesive composition can be appropriately adjusted according to the coating method of the adhesive composition, and is not particularly limited, but from the viewpoint of the amount of residual solvent, the content of the solvent is contained in the adhesive composition. It is preferably blended in the range of 10% by mass to 70% by mass.

(E) Other Materials The adhesive composition used in the present invention may contain other materials, if necessary, in addition to the above-mentioned epoxy resin, curing agent, acrylic resin and the like. For example, improve and improve workability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, releasability, flame retardancy, mold resistance, electrical properties, strength, etc. For the purpose of quality, for example, a lubricant, a plasticizer, a filler, a filler, an antioxidant, an antiblocking agent, a cross-linking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a dye, a colorant such as a pigment, etc. are included. You can go out. In addition, for example, a coupling agent such as a silane coupling agent, a titanium coupling agent, or an aluminum coupling agent may be contained. This makes it possible to improve the adhesion between the adhesive sheet and the member which is the adherend.

(F) Preparation Method Examples of the method for preparing the adhesive composition used in the present invention include a method of kneading and dispersing each component. Examples of the kneading or dispersing method include a normal kneading and dispersing machine, specifically, 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, and a high speed. Examples include a method using an impact mill, a desper, a high-speed mixer, a ribbon blender, a conider, an intensive mixer, a tumbler, a blender, a desperser, a homogenizer, and an ultrasonic disperser. When a plurality of types of hard epoxy resins are used, they are first mixed and stirred, then the curing agent is mixed and stirred, diluted with a solvent, then the soft epoxy resin is mixed and stirred, and then the acrylic resin is mixed. It is preferable to stir.

(G) Physical properties The adhesive composition used in the present invention preferably has a predetermined viscosity. Specifically, it is preferable that the adhesive sheet before curing has a viscosity sufficient to be cut into a desired size and shape. The viscosity of the adhesive composition is preferably in the range of, for example, 1 cm Stokes to 20000 cm Stokes (25 ° C.), and more preferably in the range of 1 cm Stokes to 2000 cm Stokes. When the core material is impregnated with the adhesive composition, the viscosity is preferably low, for example, in the range of 1 cm Stokes to 1000 cm Stokes.

(2) Method for Manufacturing Adhesive Sheet In the adhesive sheet of the present invention, the adhesive composition is placed on the release surface of the first release paper, dried, and then separated from the first release paper via the adhesive composition. An adhesive sheet can be obtained by laminating the second release papers so as to face each other.

Examples of the method of arranging the adhesive composition on the first paper pattern include a coating method. The specific coating method may be any method that can coat the adhesive composition, and is not particularly limited. For example, roll coat, reverse roll coat, transfer roll coat, gravure coat, gravure reverse coat, comma. Examples include coats, rod coats, blade coats, bar coats, wire bar coats, die coats, lip coats, dip coats and the like.

The first release paper and the second release paper used in the present invention may be any one as long as the adhesive composition can be arranged on the surface, and the first release paper and the second release paper may be the same. , May be different. Specific examples of the first release paper and the second release paper include a release film, a separate paper, a separate film, a separate paper, a release film, and a release paper.

Further, as the first release paper and the second release paper used in the present invention, for example, a release layer is formed on one side or both sides of a base material for release paper such as high-quality paper, coated paper, impregnated paper, and plastic film. It may be a thing. The release layer is preferably a material having releasability, and is composed of, for example, a silicone resin, an organic resin-modified silicone resin, a fluororesin, an aminoalkyd resin, a melamine resin, an acrylic resin, a polyester resin, or the like. Layers are mentioned. Any of the emulsion type, solvent type and solvent-free type can be used as these resins.
The release layer can be obtained by applying a coating liquid in which the release layer components are dispersed or dissolved to one side of a base film for release paper and curing by heating and drying. Examples of the method for applying the coating liquid include roll coating, gravure coating, spray coating and the like. Further, the release layer may be formed on the entire surface or a part of at least one side of the base film, if necessary.

In the present invention, it is preferable that the first release paper and the second release paper have a predetermined peeling force with respect to the adhesive composition. The specific peeling force is, for example, preferably in the range of 1 mN / cm to 2000 mN / cm, and more preferably in the range of 100 mN / cm to 1000 mN / cm. When the peeling force of the first release paper and the second release paper is within the above range, the first release paper and the second release paper can be sufficiently adhered to the adhesive composition, and the release is also good. It becomes possible.

Further, in the present invention, an adhesive sheet in which the core material is impregnated with the adhesive composition may be used. The adhesive sheet in this case can be obtained by, for example, the following method. Specifically, the first release paper and the core material are run on top of each other using a coating machine, and the adhesive composition is applied to the surface having the core material to impregnate the core material with the adhesive composition. Then, the adhesive composition impregnated in the core material is dried, and the second release paper is bonded to the first release paper via the adhesive composition, whereby the adhesive composition is formed. There is a method of obtaining an adhesive sheet in which the core material is impregnated with. Further, the adhesive composition is applied to the first paper pattern and dried, and the first paper pattern is laminated with a core material sheet (drum temperature 70 ° C. to 90 ° C.) via the adhesive composition, and the second paper pattern is released. The adhesive composition is applied to the paper pattern, dried, and the second paper pattern is laminated (drum temperature 70 ° C. to 90 ° C.) so as to face the first paper pattern via the core material sheet, and the adhesive is used. Examples thereof include a method of obtaining an adhesive sheet in which the core material is impregnated with the composition.

Examples of the core material used in the present invention include woven fabrics and non-woven fabrics. As the woven fabric and the non-woven fabric, generally known woven fabrics or non-woven fabrics can be used, and specific examples thereof include heat-resistant plastic fibers such as liquid crystal polymers, glass fibers, aramid fibers, and carbon fibers. A woven fabric or a non-woven fabric constructed by using these materials can be used.

(3) Adhesive Method Using Adhesive Sheet The adhesive method using the adhesive sheet in the present invention can be appropriately selected depending on the type of the member to be the adherend and the like, and is not particularly limited. For example, either one of the first release paper and the second release paper is peeled from the adhesive sheet, the surface thereof is attached to a member to be an adherend, and then the remaining release paper is peeled off, and finally 200. Examples thereof include a method of curing the adhesive sheet at a temperature of ° C. or lower.

2. 2. Member The member in the present invention is a member constituting the article obtained by the present invention, and is appropriately selected according to the type of the article. The member in the present invention may be composed of, for example, a metal material, an inorganic material, an organic material, or a composite material or a laminated material in which these are combined. Further, the form of the member of the present invention may be, for example, a layered shape, a film shape, or an uneven shape on the surface. Further, the member of the present invention may be a single body in which an adhesive sheet is arranged on the surface, or may be a plurality of bodies in which an adhesive sheet is sandwiched between them. When the member is a single body, the surface of the member can be covered with an adhesive sheet, and the adhesive sheet can be used as a protective layer or a flattening layer. When the member in the present invention has an uneven shape on the surface, the effect is that the uneven shape can be flattened by the adhesive sheet.

B. Adhesive The adhesive of the present invention contains an epoxy resin and a curing agent, and the curing agent is a material having a structure represented by the following general formula (1).

(In the above formula (1), R ¹ and R ² are -CH _2- OH or -H. However, at least one of R ¹ and R ² is -CH _2- OH.)

According to the present invention, by using a curing agent having a predetermined structure, it is possible to suppress the progress of the reaction with the epoxy resin and maintain a good pot life in an environment at room temperature, and the curing temperature of the adhesive. Can be 200 ° C. or lower.
The reason for this is presumed to be as follows.

First, in order to suppress the progress of the reaction in a normal temperature environment and maintain a good pot life, a curing agent that does not start the reaction in a normal temperature environment but starts the reaction in a high temperature (250 ° C or higher) environment is used. Need to use. However, when manufacturing an article using an adhesive, in order to improve workability and shorten the tact time, use an adhesive that starts the reaction at least in an environment of 200 ° C or lower, not in a high temperature environment. Is required. On the other hand, in the case of a one-component epoxy resin adhesive using a curing agent that starts the reaction in an environment of 200 ° C. or lower, it becomes difficult to suppress the progress of the reaction in an environment of normal temperature, and the temperature is lower than normal temperature. It is necessary to save it in the environment of. When storage in a low temperature environment is required, there is a problem that temperature control becomes troublesome, for example, a facility for cooling and storing the adhesive is required at a work site.

Therefore, the inventors of the present invention conducted various studies and obtained the following findings. That is, the inventors of the present invention pay attention to a curing agent used for a one-component epoxy resin adhesive and having a reaction starting temperature of 200 ° C. or lower, specifically, an imidazole-based curing agent having an imidazole ring. However, among them, a curing agent capable of obtaining a good pot life was examined. First, when trying to obtain a good pot life, it is preferable to use a compound capable of suppressing the reaction of the curing agent with the epoxy resin as the curing agent. Therefore, conventionally, many methods have been adopted in which a curing agent having a structure having steric hindrance is intentionally used to suppress the reaction of the curing agent with the epoxy resin. However, as a result of repeated studies by the inventors of the present invention, it has been found that a good pot life can be obtained when an imidazole-based curing agent having a predetermined structure having a hydroxyl group is used regardless of the presence or absence of steric hindrance. discovered. The specific reason for this is not clear, but it is presumed that the hydroxyl group pulls the electrons of the imidazole ring and reduces the nucleation property, thereby suppressing the reaction of the curing agent to the epoxy resin. To. The present invention has been made based on such findings.

The adhesive of the present invention contains an epoxy resin and a curing agent.
Hereinafter, the adhesive of the present invention will be described in detail.

1. 1. Hardener The hardener in the present invention has a structure represented by the above general formula (1).

Examples of the curing agent represented by the general formula (1) include the following compounds (1-1) to (1-3). In the present invention, it is preferable to use compound (1-1).

The specific description of the curing agent shall be the same as that described in the above-mentioned "A. Manufacturing method of article 1. Sheet-shaped adhesive (1) Adhesive composition (b) Curing agent". Therefore, the description here is omitted.

2. 2. Epoxy resin The epoxy resin used in the present invention is not particularly limited as long as it is a material that cures by causing a cross-linking polymerization reaction when used in combination with the above-mentioned curing agent.
The specific description of the epoxy resin is the same as that described in the above-mentioned "A. Manufacturing method of article 1. Sheet-shaped adhesive (1) Adhesive composition (a) Epoxy resin". Therefore, the description here is omitted.

3. 3. Acrylic resin The adhesive of the present invention may contain an acrylic resin. When the adhesive of the present invention contains an acrylic resin, it can be a sheet-like adhesive.

The acrylic resin used in the present invention may be any material used for a general adhesive, and is not particularly limited, but is preferably selected from the viewpoint of compatibility with the above-mentioned epoxy resin. The adhesive of the present invention can be made to have higher adhesive strength.
The specific description of the acrylic resin and the sheet-shaped adhesive can be the same as that described in the above-mentioned "A. Manufacturing method of article 1. Sheet-shaped adhesive". , The description here is omitted.

4. Other Materials The adhesive of the present invention may contain at least the above-mentioned curing agent and epoxy resin, but may also contain other materials if necessary.
The other materials contained in the adhesive of the present invention are described in the above-mentioned "A. Method for manufacturing articles 1. Sheet-shaped adhesive (1) Adhesive composition (e) Other materials". Since the contents can be the same as those described above, the description here is omitted.

Further, the adhesive of the present invention can be obtained by drying the adhesive composition constituting the adhesive. Here, the adhesive composition usually contains a solvent, and the adhesive can be obtained by drying the adhesive composition and removing the solvent. Regarding the solvent used in the adhesive composition in the present invention, the contents described in the above-mentioned "A. Manufacturing method of article 1. Sheet-shaped adhesive (1) Adhesive composition (d) Solvent". Since it can be the same as the above, the description here is omitted.

Examples of the method for preparing the adhesive composition in the present invention include a method of kneading and dispersing each component. The specific preparation method shall be the same as that described in the above-mentioned "A. Article manufacturing method 1. Sheet-shaped adhesive (1) Adhesive composition (f) Preparation method". Therefore, the description here is omitted.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. Is included in the technical scope of.

Hereinafter, the present invention will be specifically described with reference to examples.

[Example]
(Preparation of adhesive composition)
The components shown in Table 1 were mixed to prepare an adhesive composition. Specifically, 185 g of JER1009 (100% solid content manufactured by Mitsubishi Resin Co., Ltd. diluted to 43% solid content with ethyl acetate), which is a bisphenol A type epoxy resin, and JER828 (100% solid content manufactured by Mitsubishi Resin Co., Ltd.). Acrylic resin, modified methyl methacrylate-butyl acrylate-methyl methacrylate ternary copolymer (modified PMMA-BA-PMMA, Alchema M22N, 100% solid content, solid content 40 with ethyl acetate) per 120 g (Diluted to%) 75 g and 7 g of the curing agent 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW, 100% solid content manufactured by Shikoku Kasei Co., Ltd.) were mixed to prepare an adhesive composition.

(Creation of adhesive sheet)
The obtained adhesive composition was applied to a PET carrier film (thickness: 50 μm manufactured by Nippers Co., Ltd.) subjected to silicone peeling treatment as a first paper pattern using a coater. Then, the adhesive composition was dried under the conditions of 50 ° C. × 1.5 min, 70 ° C. × 1.5 min, and 110 ° C. × 1.5 min. Then, the surface of the adhesive was laminated using another PET carrier film (thickness: 50 μm manufactured by Nippers) subjected to silicone peeling treatment as the second release paper to prepare an adhesive sheet.

[Comparative Example 1]
As shown in Table 1, 2,4-diamino-6- [2'-methylimidazolilu (1')]-ethyl-s-triazine isocyanuric acid adduct (2MAOK-PW, solid content 100 manufactured by Shikoku Chemicals Corporation) as a curing agent An adhesive sheet was prepared in the same manner as in Example 1 except that%) was used.

[Comparative Example 2]
As shown in Table 1, an adhesive sheet was prepared in the same manner as in Example 1 except that 2-ethyl-4-methylimidazole (2E4MZ, 100% solid content manufactured by Shikoku Chemicals Corporation) was used as a curing agent.

[Comparative Example 3]
As shown in Table 1, an adhesive sheet was prepared in the same manner as in Example 1 except that 2-methylimidazole (2MZ-H, 100% solid content manufactured by Shikoku Chemicals Corporation) was used as a curing agent.

[Evaluation]
1. 1. Preservation test The obtained adhesive sheet was stored in a thermostatic chamber at a temperature of 23 ° C. and a humidity of 50% for a predetermined number of days in a thermostatic chamber at a temperature of 40 ° C. Then, the adhesive sheet was taken out from the thermostatic chamber, the first release paper was peeled off, and the surface of the adhesive was pressed with a finger to evaluate as follows.
"○": When finger marks remain on the surface of the adhesive as before storage "△": When finger marks remain on the surface of the adhesive but the number of finger marks decreases compared to before storage "×": If no finger marks are left on the surface of the adhesive

2. 2. Shear test The obtained adhesive sheet was cut into 25 mm × 12.5 mm, the first paper pattern was peeled off, and the adhesive sheet was pressure-bonded to SUS. After that, the second release paper was peeled off, crimped with another test piece, cured under the conditions of a temperature of 180 ° C. and a curing time of 30 min while applying a load of N = 3, and at room temperature (23 ° C.). A sample for measurement was prepared by allowing to cool. Then, a tensile tester (product name: RTA-1T, manufactured by A & D Co., Ltd.) was used to perform a shear test at room temperature (based on JIS K6850, tensile speed 10 mm / min).

[result]
1. 1. Preservation test As shown in Table 2, in the examples, good preservability could be obtained in both the homeothermic chambers 1 and 2. On the other hand, in Comparative Example 1, the storage stability decreased with the passage of days, and in Comparative Examples 2 and 3, the storage stability could not be obtained. Therefore, in the examples, it was found that a good pot life could be maintained.

2. 2. Shear test As shown in Table 3, in the examples, when stored in a constant temperature room (under the condition of a temperature of 40 ° C.), the shear strength is the same at the start of storage and after 4 weeks (28 days) have passed since the start of storage. It was confirmed that. Therefore, in the examples, it was found that good pot life can be maintained and curing at a temperature of 200 ° C. or lower is possible. On the other hand, in Comparative Examples 1 to 3, the predetermined shear strength could not be maintained at the start of storage and after 4 weeks (28 days) had elapsed from the start of storage.

1 ... Sheet-shaped adhesive 1'... Adhesive layer 1 "... Adhesive composition 2 ... Member 3a ... 1st paper pattern 3b ... 2nd paper pattern 4 ... Core material 10 ... Article 20 ... Adhesive sheet

Claims (11)

It has an adhesive step of arranging a sheet-shaped adhesive on a member or between two said members and curing the adhesive at a temperature of 200 ° C. or lower.
The adhesive is a one-component epoxy resin adhesive containing a curing agent and an epoxy resin .
The curing agent is an imidazole-based curing agent having a hydroxyl group on the imidazole ring.
Further, the adhesive is an adhesive whose shear strength 28 days after the start of storage maintains the shear strength at the start of storage when the adhesive is subjected to a storage test under a temperature condition of 40 ° C. A method of manufacturing an article characterized by. The method for producing an article according to claim 1, wherein the adhesive contains an acrylic resin. Contains epoxy resin and hardener,
An adhesive characterized in that the curing agent has a structure represented by the following general formula (1).
(In the above formula (1), R ¹ and R ² are -CH _2- OH or -H. However, at least one of R ¹ and R ² is -CH _2- OH.) The adhesive according to claim 3 , further comprising an acrylic resin and being in the form of a sheet. The adhesive according to claim 3 or 4, wherein when the adhesive is subjected to a storage test under a temperature condition of 40 ° C., the shear strength 28 days after the start of storage maintains the shear strength at the start of storage. .. Contains epoxy resin and hardener,
An adhesive sheet in which the curing agent contains an adhesive composition having a structure represented by the following general formula (1).
(In the above formula (1), R ¹ and R ² are -CH _2- OH or -H. However, at least one of R ¹ and R ² is -CH _2- OH.) The adhesive sheet according to claim 6 , further comprising an acrylic resin. The adhesive sheet according to claim 6 or 7 , further comprising the adhesive composition and a core material. Any of claims 6 to 8 in which the shear strength 28 days after the start of storage maintains the shear strength at the start of storage when the adhesive sheet is subjected to a storage test under a temperature condition of 40 ° C. Adhesive sheet as described in the section. An adhesive containing an epoxy resin and a curing agent that can be cured by causing a cross-linking polymerization reaction at a temperature of 200 ° C. or lower when used in combination with the epoxy resin.
The curing agent is an imidazole-based curing agent having a hydroxyl group on the imidazole ring.
The adhesive is such that when the adhesive is subjected to a storage test under a temperature condition of 40 ° C., the shear strength 28 days after the start of storage maintains the shear strength at the start of storage. An adhesive sheet having an adhesive composition containing an epoxy resin and a curing agent that can be cured by causing a cross-linking polymerization reaction at a temperature of 200 ° C. or lower when used in combination with the epoxy resin.
The curing agent is an imidazole-based curing agent having a hydroxyl group on the imidazole ring.
The adhesive sheet is an adhesive sheet in which the shear strength 28 days after the start of storage maintains the shear strength at the start of storage when the adhesive is subjected to a storage test under a temperature condition of 40 ° C. ..