JPH1143660A - Adhesive composition and process for adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy beam curable adhesive composition suitable for the adhesion of substrates which do not transmit light mutually and a process for the adhesion of such substrates. SOLUTION: An adhesive composition comprises (A) an acrylic elastomer having a functional group, (B) an epoxy resin having two or more epoxy groups in the molecule and (C) a photocationic polymerization initiator and a process for the adhesion comprises coating the adhesive composition on respective surfaces of two substrates or the surface of one substrate, irradiating the coated surfaces or surface with an energy beam and then joining the coated surfaces to each other or the coated surface of one substrate to the other substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive composition and a bonding method suitable for bonding opaque substrates such as metal, plastic, rubber, woodwork, glass and the like. In particular, the present invention relates to an adhesive composition and a bonding method suitably used for bonding a plastic film used for a flexible printed wiring board and a reinforcing plate.

[0002]

2. Description of the Related Art Conventionally, flexible circuit boards, chip carrier tapes and the like have been prepared by using a copper-clad film (for example, a polyimide film, a polysulfone film, a polyethersulfone) using a heat-curable adhesive for a so-called flexible printed wiring board. Film, a thermoplastic heat-resistant engineering plastic film such as a polyetherimide film) and a reinforcing plate are often used by bonding. Specific examples of the adhesive used here include a thermosetting resin adhesive mainly composed of a rubber-modified epoxy resin, a polyamide-modified epoxy resin, an epoxy-urethane-modified acrylic resin, a phenol resin and the like.

[0003]

However, when bonding with a thermosetting resin adhesive, an aromatic polyamine or a cationic polymerization type curing agent (boron trifluoride amine) is used as the curing agent in order to obtain sufficient adhesive performance. Complex, boron trifluoride-ether complex, etc.)
There was a drawback that a long press was required, and workability was poor. Moreover, these are not suitable for the adhesive between the component mounting reinforcing plate and the flexible printed wiring board because the flow of the adhesive is large.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, they can adhere to each other with opaque substrates, have excellent adhesiveness, and have a long pot life. In particular, the present invention succeeded in providing an energy ray-curable adhesive composition and an adhesive method suitable for an adhesive for flexible printed wiring boards.

That is, the present invention comprises (1) an acrylic elastomer (A) having a functional group, an epoxy resin (B) having two or more epoxy groups in one molecule, and a cationic photopolymerization initiator (C). (2) an adhesive composition according to (1), which contains a compound (D) having at least two hydroxyl groups in a molecule, and (3) a lactone compound (E). ) Or (2), the adhesive composition according to (1) to (3), after applying the adhesive composition according to (1) to (3) on each of the two substrates or on one of the two substrates, The present invention relates to a method for bonding two substrates, which comprises irradiating an application surface with energy rays and then bringing the application surfaces into close contact with each other or between the application surface and another substrate.

Hereinafter, each of the components (A), (B) and (C) constituting the adhesive composition of the present invention, and the components (D) and (E) as optional components will be specifically described.

As the acrylic elastomer (A) component, known acrylic elastomers can be used, but in general, one (meth) acrylic acid ester is used.
A polymer having at least one functional group as a cross-linking point containing at least one species or more as a main component, or at least one type of the functional group-containing monomer as a (graft) copolymer with the main component monomer. Polymerized polymers are included. Here, examples of the functional group include an epoxy group, a carboxyl group, and a hydroxyl group.

More specifically, the acrylic elastomer (A) comprises (a) one or more (meth) acrylic acid esters in a large proportion, which comprises (b) an epoxy group, (c) An acrylic elastomer obtained by copolymerizing a monomer having one or more functional groups selected from the group consisting of a carboxyl group and (d) a hydroxyl group can be used.

Specific examples of the monomers (a) to (d) are shown below. As the (meth) acrylate (a), for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (Meth) acrylate and the like. Also,
Examples of the epoxy group-containing monomer (b) include glycidyl ethers such as vinyl glycidyl ether and allyl glycidyl ether; and glycidyl (meth) acrylates.

Also, a carboxyl group-containing monomer (c)
Examples thereof include (meth) acrylic acid, itaconic acid, maleic acid, and maleic anhydride. Examples of the hydroxyl group-containing monomer (d) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate.

Further, if necessary, other vinyl monomers such as styrene, α-methylstyrene, vinylidene chloride, (meth) acrylonitrile, and vinyl acetate may be copolymerized.

The acrylic elastomer (A) includes:
Specifically, ARONTAC S-1511L, S-151
1X, S-1017 (trade name, manufactured by Toa Gosei Chemical Co., Ltd.); Knoxtite PA-501, PA-502
(Nippon Mektron, product name); Teisan Resin WS
022, WS023, SG51, SG80, SG90
(Trade name, manufactured by Teikoku Chemical Co., Ltd.); AR-51 (trade name, manufactured by Zeon Corporation) and the like. These can be used alone or in combination of two or more.

The acrylic elastomer (A)
May have any one of an epoxy group, a carboxyl group, and a hydroxyl group, and among them, those having a low-temperature reactive epoxy group or a hydroxyl group are preferable. The molecular weight is about 5,000 to 500,000, preferably about 10,000 to 100,000 as an average molecular weight.

The epoxy resin (B) is not particularly limited, but generally has two or more epoxy groups in one molecule, and may be any epoxy resin other than the acrylic elastomer (A), for example, glycidyl. Compounds and alicyclic epoxy compounds. Its molecular weight is
The average molecular weight is preferably about 5000 or less.

Examples of the glycidyl compound include a glycidyl ether compound and a glycidyl ester compound, and a glycidyl ether compound is preferable. Specific examples of the glycidyl ether compound include, for example, 1,3-bis (2,3-epoxypropoxy)
Benzene, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin,
Aromatic glycidyl ether compounds such as trisphenol methane type epoxy resin, and aliphatic glycidyl ether compounds such as 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, propylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether. Specific examples of the glycidyl ester compound include, for example, glycidyl ester of linoleic acid dimer.
These glycidyl compounds can be used alone or in combination of two or more.

Specific examples of the alicyclic epoxy compound include:
4-vinylcyclohexene dioxide, (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate, di (3,4-epoxycyclohexyl) adipate, bis (2,3-epoxycyclopentyl) ether, di ( 2,3-epoxy-6
Methylcyclohexylmethyl) adipate, dicyclopentadienedioxide and the like. These alicyclic epoxy compounds can be used alone or in combination of two or more.

Examples of the cationic photopolymerization initiator (C) include 4,4'-bis [diphenylsulfonio] phenylsulfide-bis-hexafluoroantimonate and 4,4'-bis [diphenylsulfonio] Phenyl sulfide-bis-hexafluorophosphate,
4,4'-bis [di (β-hydroxyethoxy) phenyl sulfonio] phenyl sulfide-bis-hexafluoroantimonate, 4,4'-bis [di (β-hydroxyethoxy) phenyl sulfonio] phenyl sulfide -Bis-hexafluorophosphate, triphenylsulfonium hexafluoroantimonate,
2,4-diethyl-7- [di (p-methylphenyl) sulfonio] thioxanthone hexafluoroantimonate, 2-isopropyl-7- [di (p-fluorophenyl) sulfonio] thioxanthone hexafluorophosphate, 2-chloro- 7- [di (p-methylphenyl (sulfonio) thioxanthone hexafluorophosphate, 1-chloro-4-propyloxy-7-
[Diphenylsulfonio] thioxanthone hexafluoroantimonate and the like can be mentioned.

(A) to Constituting the Adhesive Composition of the Present Invention
As the use ratio of the component (C), the mixing ratio of the acrylic elastomer (A) / epoxy resin (B) is 1/1 to 10/1, preferably 2/1 to 6/1 in terms of the solid content weight ratio. . Acrylic elastomer (A) / epoxy resin (B)
If the compounding ratio is smaller than 1/1, the solder heat resistance is reduced. Conversely, if it is greater than 10/1, the adhesive strength will decrease. The proportion of the cationic photopolymerization initiator (C) used is (A)
And 0.01 parts by weight based on 100 parts by weight of the total amount of component (B).
10 to 10 parts by weight, particularly preferably 0.05 to 5 parts by weight.
Parts by weight.

The adhesive composition of the present invention comprises (A) to (C)
In addition to the components, a compound (D) having at least two hydroxyl groups in the molecule and a lactone compound (E) can be preferably used.

The component (D) may be a compound having at least two hydroxyl groups in a molecule other than the acrylic elastomer (A), and its molecular weight is preferably about 2000 or less. Specific examples thereof include, for example, ethylene glycol, propylene glycol, polyethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, tricyclodecane dimethylol, 1,4-dimethylolcyclohexane, benzene -1,4-dimethylol, bisphenol A polyethoxydiol, bisphenol F polyethoxydiol, trimethylolpropane, trimethylolpropane polyethoxytriol, trimethylolpropane polypropoxytriol, pentaerythritol polyethoxytetraol, ditrimethylolpropanepolyethoxytetra All, ditrimethylolpropane polypropoxytetraol, polytetramethylene glycol,
A polyol compound (D ₁ ) such as polycarbonate diol, the above-mentioned polyol compound (D ₁ ) and maleic acid, succinic acid, adipic acid, phthalic acid, isophthalic acid,
Polyester polyol compounds (D ₂ ) which are polybasic acids such as terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, hydrogenated dimer acid, trimellitic acid or reaction products with these acid anhydrides; ₁ ) or a polycaprolactone polyol compound (D ₃ ) which is a reaction product of a polyester polyol compound (D ₂ ) and ε-caprolactone;
Novolak resins, phenolic resins (D ₄ ) such as cresol / novolak resins, and the like can be mentioned. By using these components (D) in the composition of the present invention, curability and adhesion can be improved.

As a specific example of the component (E), for example, ε-
Caprolactone, γ-valerolactone, β-butyrolactone and the like can be mentioned. By using these components (E) in the composition of the present invention, it is possible to improve the adhesive strength and easily adjust the viscosity.

The proportion of the components (D) and (E) in the composition of the present invention is 0 to 100 parts by weight based on 100 parts by weight of the total amount of the components (A) to (C). Parts by weight, particularly preferably 5 to 50 parts by weight. The component (E) is preferably from 0 to 100 parts by weight, particularly preferably from 5 to 100 parts by weight.
50 parts by weight.

In the composition of the present invention, if necessary, cationically polymerizable substances such as oxetane compounds, bicycloorthoester compounds, spiroorthocarbonate compounds, antioxidants, leveling agents, defoamers, inorganic fillers ( For example, anhydrous silica, aluminum hydroxide, barium sulfate, etc.), a silane coupling agent, organic solvents and the like can be used in combination.

The adhesive composition of the present invention comprises (A) to (E)
The components can be prepared by heating, dissolving, mixing and the like.

In order to adhere two substrates using the adhesive composition of the present invention, for example, the following method may be used. That is,
The adhesive composition of the present invention is applied to each surface of two or the same substrate or different substrates using a coating machine such as a roll coater so as to have a thickness of 5 to 100 μm. After that (the adhesive composition can be applied on release paper and then transferred onto a substrate using this), the residual ratio of epoxy groups in the applied adhesive composition of the present invention is usually Irradiation of energy rays, for example, ultraviolet rays, electron beams, or the like (adjustment of energy amounts of energy rays) so that the energy rays fall within the range of 50 to 95%, and then the energy ray irradiation surfaces on the two base materials or one of The irradiated coating surface is bonded to the other substrate, and the room temperature (about 20 ° C.) or the heating (about 20 ° C.)
(−200 ° C.) for about several seconds to about 24 hours. The residual ratio of epoxy groups in the adhesive composition is expressed as a percentage of the amount of epoxy groups after irradiation with energy rays such as ultraviolet rays with respect to the amount of initial epoxy groups determined by infrared absorption spectrum analysis. It was done.

In order to apply the adhesive composition of the present invention to a film or a reinforcing plate, the adhesive composition is applied to either one of the surface of the film or the reinforcing plate (solid amount: 40 μm). Dry in a furnace to dry the solvent), irradiate the coated surface with ultraviolet rays in the same manner as above, and then attach another adherend (substrate) to the coated surface of the adhesive composition, using a hot press Then, a method of heating and pressing at 130 to 180 ° C. at a pressure of 5 to 40 kg / cm ² and curing is adopted.

As the reinforcing plate to which the adhesive composition of the present invention is applied, aluminum plate, silicon steel plate, paper phenol laminate,
Glass epoxy laminates, polypropylene, polyethylene and the like can be mentioned. Further, the film to which the adhesive composition of the present invention is applied is not particularly limited as long as it is a polymer film, but is particularly preferably used for a flexible printed wiring board, and specifically, for example, a polyimide film, a polyester film, and a poly film. Examples include an ether ketone film, a polyether sulfone film, and an ultra-thin laminate.

The adhesive composition of the present invention may be used for various base materials such as an adhesive for flexible printed wiring boards.
It is also suitably used for bonding various metals, paper, various plastics, wood, ceramics, glass and the like.

[0029]

Next, the present invention will be described in detail with reference to examples. They do not limit the scope of the invention. In the examples, parts mean parts by weight.

Example 1 SG90 (trade name, manufactured by Teikoku Chemical Industry Co., Ltd.) as an acrylic elastomer was dissolved in methyl ethyl ketone.
80 parts by weight of a 0% by weight solution, 3.95 parts of bisphenol A diglycidyl ether, 5.0 parts of bis (3,4-epoxycyclohexyl) adipate, 4,4'-bis [diphenylsulfonio] phenyl sulfide-bis-hexa 0.013 parts of fluorophosphate was mixed and stirred to obtain an adhesive solution.

Thereafter, the adhesive solution was applied on a release paper so as to have a thickness of 40 μm in solid form and dried at 120 ° C. for 5 minutes to form a film. Using this, the adhesive formed into a film is transferred onto an aluminum reinforcing plate, and the transferred surface is irradiated with ultraviolet rays so that the residual ratio of epoxy groups in the adhesive composition becomes 90%. The plate was bonded to the plate and pressed at 80 ° C. under a pressure of 10 kg / cm ² for 5 minutes. The adhesive strength (kg / cm) and solder heat resistance (260 ° C. ×
Second) and the resistance to run-off (mm) was evaluated. Table 1 shows the results.

Example 2 SG80 (trade name, manufactured by Teikoku Chemical Industry Co., Ltd.) was dissolved in methyl ethyl ketone as an acrylic elastomer.
70 parts by weight of a 0% by weight solution, a phenol novolak type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 15)
4) 3.5 parts, 2.5 parts of polytetramethylene glycol (molecular weight 650), 5.0 parts of bis (3,4-epoxycyclohexyl) adipate, 2-chloro-7- [di (p
-Methylphenyl) sulfonio] thioxanthone hexafluorophosphate (0.013 parts) was mixed and stirred to obtain an adhesive solution. Thereafter, an adhesive was obtained and evaluated in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 80 parts of a 20% by weight solution of SG90 dissolved in methyl ethyl ketone as an acrylic elastomer, 3.95 parts of bisphenol A diglycidyl ether, 5.0 parts of bis (3,4-epoxycyclohexyl) adipate, 4,4 ′
1.25 parts of diaminodiphenylmethane and 0.125 part of a curing accelerator BF ₃ -MEA (Cation polymerization catalyst, trade name, manufactured by Hashimoto Kasei Co., Ltd.) were mixed and stirred to obtain an adhesive solution. Thereafter, an adhesive was obtained and evaluated in the same manner as in Example 1. Table 1 shows the results.

[0034]

Table 1 Adhesive strength Solder heat resistance Resistance to run-off (kg / cm) (260 ° C. × sec) (mm) Example 1 2.5 60 or more 0.1 Example 2 2.0 60 or more 0.1 Comparative Example 1 0.5 5 0.1

(A) Adhesive strength: Conforms to JIS C 6481 (I) Solder heat resistance: Conforms to JIS C 6481 (C) Flow-out resistance: A hole of 0.8 mm is made in an FPC (flexible printed wiring board). The exuding width of the adhesive after pressing is measured.

As is clear from the evaluation results, the adhesive composition of the present invention is excellent in adhesive strength and solder heat resistance.

[0037]

The adhesive composition of the present invention can be cured at a low temperature and has excellent adhesive strength and solder heat resistance, and is particularly suitable for a reinforcing plate of a flexible printed wiring board.

Claims (4)

[Claims] An adhesive composition comprising an acrylic elastomer (A) having a functional group, an epoxy resin (B) having two or more epoxy groups in one molecule, and a cationic photopolymerization initiator (C). 2. The adhesive composition according to claim 1, which comprises a compound (D) having at least two hydroxyl groups in the molecule. 3. The composition according to claim 1, which contains a lactone compound (E).
Or the adhesive composition according to 2. 4. After applying the adhesive composition according to any one of claims 1 to 3 on each of the two substrates, or on one of the surfaces, irradiate the application surface with energy rays. ,
Next, a method of bonding two substrates, wherein the two surfaces are closely adhered to each other or the other surface.