JPH0376351B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a composition for adhering a plastic film and metal foil of a flexible printed wiring board, and particularly to a composition that has excellent heat resistance, chemical resistance, flexibility, etc. The present invention relates to an adhesive composition for flexible printed wiring boards. [Technical background of the invention and its problems] In recent years, as electronic devices have become more sophisticated and diversified, flexible printed wiring boards that are lightweight and capable of three-dimensional wiring have attracted attention. In particular, flexible printed wiring boards using polyimide film as an insulating substrate account for most of the demand for flexible printed wiring boards because they can withstand high temperatures during soldering and various bonding processes. However, since polyimide film has poor surface activity, it is manufactured by laminating it with metal foil such as copper or aluminum using an adhesive. The main components of the adhesive used here are polymers such as acrylonitrile-butadiene, acrylic, and polyamide, which have poor heat resistance, chemical resistance, and electrical insulation properties, but they do not have the excellent heat resistance that polyimide film originally has. However, it had the disadvantage of lowering chemical resistance and electrical insulation. [Object of the Invention] The object of the present invention was to solve these conventional drawbacks, and to provide an adhesive composition for flexible printed wiring boards that has excellent heat resistance, chemical resistance, flexibility, electrical insulation properties, and adhesive properties. It tries to provide something. [Summary of the Invention] As a result of intensive research to achieve the above object, the present invention found that a resin composition based on a solvent-soluble polyimide resin-epoxy resin achieved the above object, and was developed as an adhesive for flexible printed wiring boards. It has been found that it is suitable for (A) (a) A polyimide resin obtained by reacting polyamines or polyisocyanates and polycarboxylic acid anhydride that are soluble in dimethylformamide, dimethylacetamide or N-methyl-2-pyrrolidone, and (b) (B) Copolymerized nylon, polyvinyl formal, carboxyl group-containing elastomer, or epoxy-containing elastomer is added to a resin composition consisting of an epoxy resin having two or more epoxy groups in one molecule and a curing agent for the resin composition 100. This is an adhesive composition for a flexible printed wiring board, characterized in that it is blended in an amount of 10 to 100 parts by weight. The polyimide resin (A) (a) used in the present invention is a polyimide resin obtained by reacting polyamines or polyisocyanates with polycarboxylic acid anhydride, and includes dimethylformamide, dimethylacetamide, N-methyl- It is soluble in specific proton organic solvents such as 2-pyrrolidone. Specifically, polyimide 2080 (manufactured by Atupjiyon Co., Ltd., product name)
etc. It is estimated that polyimide 2080 has the following structural formula. (b) Epoxy resins having two or more epoxy groups in one molecule used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, and cresol novolak type epoxy resin. Epoxy resin, ester epoxy resin, ether epoxy resin,
Examples include urethane-modified epoxy resins, alicyclic epoxy resins, hydantoin-based epoxy resins, amino-based epoxy resins, heterocyclic epoxy resins, etc.
These can be used alone or as a mixture of two or more. Further, as the curing agent for these epoxy resins, any generally known curing agent can be used. For example, aliphatic polyamines, aromatic polyamines, heterocyclic polyamines, secondary or tertiary amines, organic acid anhydrides, polyamide resins, polysulfide resins, boron trifluoride amine complexes,
Examples include imidazole, dicyandiamide, polymercaptan, aniline resin, novolac resin, resol resin, etc., and any of them can be used alone or in a mixed system of two or more. The amount of curing agent to be added to the epoxy resin is selected depending on the characteristics and the like within the range in which each curing agent is normally used. The blending ratio of (a) solvent-soluble polyimide resin and (b) epoxy resin having two or more epoxy groups in one molecule and its curing agent is 10 to 90% by weight of the solvent-soluble polyimide resin, and the epoxy resin and It is also necessary to include a curing agent in an amount of 90 to 10% by weight. If the amount of solvent-soluble polyimide resin is less than 10% by weight, the heat resistance, chemical resistance, and flexibility will decrease, and if it exceeds 90% by weight, the adhesion with the polyimide film will decrease. I also don't like it. The amount of epoxy resin and curing agent is 10
If it is less than 90% by weight, the adhesiveness and electrical insulation properties will be lowered, and if it exceeds 90% by weight, the heat resistance will be lowered, which are both undesirable. Examples of the polymer (B) having an epoxy group or a functional group reactive with an epoxy group in the molecule used in the present invention include acrylic resins having a carboxyl group, an amino group, a hydroxyl group, an isocyanate group, an amide group, etc. in the molecule. Examples include nitrile resin, butadiene resin, acrylic resin, polyamide resin, polyester resin, polyurethane resin, polyvinyl butyral resin, polyolefin resin, and the like. These can be used alone or in a mixture of two or more.
The blending amount of the polymer having an epoxy group or a functional group reactive with an epoxy group in the molecule is as follows: (a) the solvent-soluble polyimide resin; 10 to 100 parts by weight of the resin composition consisting of the curing agent and
It is necessary to mix 100 parts by weight. If the amount is less than 10 parts by weight, the flexible adhesive properties will decrease, and if it exceeds 100 parts by weight, the heat resistance,
Chemical resistance and electrical insulation properties are both unfavorable. The adhesive composition of the present invention is usually used after being dissolved in an organic solvent such as acetone, methyl ethyl ketone, methanol, dioxane, toluene, dichloroethane, tetrahydrofuran, methyl cellosolve, or dimethyl formamide. For adhesion work, apply to the surface of plastic film or metal foil with a regular coating device to a film thickness of 10 to 50 μm, and
Dry for 0.5 to 30 minutes at a temperature of 80 to 250 degrees Celsius, and then overlap so that the surface of one adherend is in contact with the surface of ^the adhesive layer.
This is done by heating and pressurizing for 1 minute. If more thorough curing is required, after-curing is performed. [Effects of the Invention] The adhesive composition for flexible printed wiring boards of the present invention has heat resistance, chemical resistance, flexibility, electrical insulation,
It has excellent adhesive properties and is particularly resistant to deterioration due to heating, which greatly improves the conventional drawbacks and can be used in a wide range of applications. [Examples of the Invention] The present invention will be specifically described below with reference to Examples.
In Examples and Comparative Examples, "parts" and "%" mean "parts by weight" and "% by weight," respectively. Example 1 30 parts of solvent-soluble polyimide resin 2080 (trade name manufactured by Updillon), 70 parts of urethane-modified epoxy resin (epoxy equivalent: 250), 5 parts of soluble copolymerized nylon, and 6 parts of dicyandiamide were mixed with dimethylformamide/ethyl alcohol = 3/ 1 was mixed and dissolved to obtain an adhesive composition with a concentration of 20%. This adhesive composition was applied to a 50μ thick polyimide film to a thickness of 20μ, and after drying at 160°C for 15 minutes, a 35μ thick copper foil was heat-pressed onto the coated surface using a roll method for after-cure. A flexible copper clad board was manufactured. Crimping conditions are 5 at 150℃.
Kg/cm ² , 0.5 seconds, and after-cure conditions were heating at 170° C. for 3 hours. The properties of this flexible copper clad board are shown in Table 1. Example 2 25 parts of solvent-soluble polyimide resin 2080, bisphenol type epoxy resin (epoxy equivalent 190)
55 parts of novolac type phenolic resin, 20 parts of novolac type phenolic resin, 10 parts of polyvinyl butyral, and 0.3 parts of benzyldimethylamine were mixed and dissolved in dimethylformamide/methyl cellosolve=3/1 to obtain an adhesive composition having a concentration of 25%. A flexible copper clad board was obtained using this adhesive composition in the same manner as in Example 1, and its properties were tested. The results are shown in Table 1. Example 3 50 parts of solvent-soluble polyimide resin 2080, phenol novolak type epoxy resin (epoxy equivalent
185) 50 parts, boron trifluoride monoethylamine 2.5
and 25 parts of carboxyl group-containing acrylonitrile butadiene rubber were mixed and dissolved in dimethylformamide/dioxane = 2/1 to obtain an adhesive composition having a concentration of 18%. A flexible copper clad board was obtained using this adhesive composition in the same manner as in Example 1, and its properties were tested. The results are shown in Table 1. Example 4 35 parts of solvent-soluble polyimide resin 2080, bisphenol type epoxy resin (epoxy equivalent 190)
50 parts of diaminodiphenylsulfone, and 15 parts of epoxy group-containing acrylic rubber were mixed and dissolved in dimethylformamide/dioxane=2/1 to obtain an adhesive composition having a concentration of 20%. A flexible copper clad board was obtained using this adhesive composition in the same manner as in Example 1, and its properties were tested. The results are shown in Table 1. Comparative Example 1 60 parts of carboxyl group-containing acrylonitrile butadiene elastomer, 40 parts of bisphenol type epoxy resin (epoxy equivalent 190), 3.2 parts of dicyandiamide, and 0.1 part of benzyldimethylamine were mixed into methyl ethyl ketone/methyl cellosolve = 2/
1 was mixed and dissolved to obtain an adhesive composition having a concentration of 18%. Using the obtained adhesive composition, a flexible copper-clad board was obtained in the same manner as in Example 1, and its properties were tested. The results are shown in Table 1. Comparative Example 2 Alkyl elastomer (ethyl acrylate/
methacrylic acid = 98/2 copolymer) 50 parts, bisphenol type epoxy resin (epoxy equivalent 190)
50 parts of imidazole 2PHZ-LN (trade name, manufactured by Shikoku Kasei Co., Ltd.) were mixed and dissolved in methyl ethyl ketone/toluene = 2/1 to obtain an adhesive composition having a concentration of 20%. A flexible copper clad board was obtained using this adhesive composition in the same manner as in Example 1, and its properties were tested. The results are shown in Table 1. 【table】

Claims (1)

[Scope of Claims] 1 (A)(a) Obtained by reacting polyamines or polyisocyanates soluble in dimethylformamide, dimethylacetamide or N-methyl-2-pyrrolidone with polycarboxylic acid anhydride A resin composition consisting of a polyimide resin, (B) an epoxy resin having two or more epoxy groups in one molecule and its curing agent, and (B) a copolymerized nylon, polyvinyl formal, carboxyl group-containing elastomer, or epoxy-containing An adhesive composition for a flexible printed wiring board, characterized in that 10 to 100 parts by weight of an elastomer is blended with respect to 100 parts by weight of the resin composition. 2. A patent claim in which the resin composition consists of (a) 10 to 90 parts by weight of a polyimide resin, and (b) 90 to 10 parts by weight of an epoxy resin having two or more epoxy groups in one molecule and its curing agent. The adhesive composition for flexible printed wiring boards according to item 1.