JPH0337284A - Adhesive for copper foil - Google Patents

Abstract

PURPOSE:To obtain a high-solid adhesive for a copper foil which has excellent solvent resistance and peeling strength and which is brought into B-stage by ultraviolet rays by compounding a mixture of a photopolymerizable resin and a thermosetting resin with a specified amt. of an org. compd. acting as a reaction initiator. CONSTITUTION:An adhesive for a copper sheet is obtd. by compounding 100 pts.wt. sum of a photopolymerizable resin [e.g. a resin obtd. by polymerizing a monomer with 1 or more (meth)acryloyl groups per molecule or an acryl oligomer alone or mixing two or more thereof and polymerizing them] and a thermosetting resin (e.g. an epoxy resin, a phenol resin, an imide resin, etc.) with 0.1-10 pts.wt. org. compd. acting as a reaction initiator (e.g. an org. compd. of acetophenone type, benzoin type, etc.). By preparing a B-stage condition by using ultraviolet rays and further preparing a C-stage by heating, an adhesive for a copper foil with excellent solvent resistance and an increased solid content of adhesive can be obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a copper foil adhesive used for adhering copper foil to a base material of a steel clad laminate for printed wiring boards, and in particular to By creating a B stage state and then creating a C stage state by heating, it has excellent solvent resistance.
This invention relates to an adhesive for copper foil that has an increased solids content.

[Conventional technology]

In general, the manufacturing process of printed wiring boards by copper foil etching of steel-clad laminates for printed wiring boards used in electrical equipment, electronic equipment, computing equipment, communication equipment, etc. includes punching holes, etching non-circuit parts, and solvent treatment. After that, soldering is done to attach the parts. Further, printed wiring boards manufactured using other manufacturing methods also require harsh processing to form circuit parts. At this time, the copper-clad laminate is required to have a peel strength of 1 in heat resistance, and therefore the adhesive for bonding the base material and the copper foil is required to meet these requirements.

Conventionally, adhesives for copper foil as described above have typically been made of polyvinyl acetal resin and thermosetting resin as main components.

[Problem to be solved by the invention]

However, since conventional adhesives such as those mentioned above use polyvinyl acetal resin, the solid content is 15 to 30%.
The remainder is accounted for by 85-70% of the solvent. Therefore, in order to B-stage the adhesive, it is necessary to evaporate as much as 85 to 70% of the solvent, and the only method available was a forced drying method using a heating furnace. In this heating drying method for staging, it is necessary to create a temperature gradient in the drying oven in order to increase productivity and suppress bubbles in the adhesive due to bumping of the solvent. It was not possible to reduce the equipment space. Furthermore, with adhesives whose main components are a combination of polyvinyl acetal resin and thermosetting resin, there is a limit to the improvement in heat resistance (5) and peel strength, and furthermore, because the adhesive viscosity increases, the amount of solvent used due to high solidification is limited. Therefore, it was difficult to reduce the adhesive cost. Also, low molecular weight substances in the adhesive raw materials evaporate in the high temperature section of the drying oven and condense in the low temperature section of the drying oven.

It was not possible to prevent the occurrence of stains on the surface of the copper foil due to the falling of the condensate. Furthermore, it has not been possible to reduce the environmental pollution caused by solvent vapor generated during B-stage drying and the adverse effects on the human body of the coating worker caused by the evaporated solvent. Furthermore, the production of printed wiring boards by copper foil etching of copper-clad laminates involves a process of cleaning the copper-clad laminates with a solvent, but in this process, the conventional combination of polyvinyl acetal resin and thermosetting resin is used. Because adhesives swell or dissolve when used with objects, there has been a need for adhesives with excellent resistance to solvents (particularly halogenated organic solvents).

The present invention was made in view of these current circumstances, and an object of the present invention is to provide an adhesive for copper foil with a high solid content, which has excellent solvent resistance and peel strength, and uses ultraviolet rays for B-stage formation. It is.

[Means and effects for solving the problems] The adhesive for copper foil of the present invention contains a photopolymerizable resin, a thermosetting resin, and an organic compound that acts as a reaction initiator.
0.1 part of organic compound per 100 parts by weight of thermosetting resin
~10 parts by weight is blended.

According to a preferred embodiment of the invention, the solid content in the adhesive is 5
It is 0-100%.

Photopolymerizable resins used in the present invention include acrylic monomers and acrylic oligomers.
It has one or more 7 acryloyl or methacryloyl groups per molecule, and is broadly classified into aliphatic acrylates, alicyclic acrylates, aromatic acrylates, functional group-containing acrylates, and special acrylates. First, aliphatic,
Alicyclic acrylates include (1) Monofunctional acrylates such as alkyl groups such as 2-ethylhexyl acrylate and lauryl acrylate, alkoxyalkylene glycol types such as methoxydiethylene glycol acrylate, cyclohexyl types, and tetrahydrofurfuryl. type, isobonyl type, dicyclopentenyl type,
Examples include amine type and fluorine type alicyclic type, and polyfunctional acrylates include 1゜4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6
- Alkyl type represented by hexanediol diacrylate, alkylene glycol type represented by diethylene glycol diacrylate, triethylene glycol diacrylate, ester type represented by hydroxypivalate neopentyl, glycol diacrylate, trimethylolpropane triacrylate Acrylate, trimethylolpropane type represented by ethoxylated trimethylolpropane triacrylate, pentaerythritol type represented by pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and isocyanate represented by tris(acryloxyethyl) isocyanurate. Nurate type, dicyclopentanyl diacrylate, and alicyclic type represented by ethoxylated hydrogenated bisphenol A diacrylate.

(2) As aromatic acrylates, phenyl type represented by phenyl acrylate, benzyl type represented by benzyl acrylate, phenoxy type represented by phenoxydiethylene glycol acrylate, phenoxy type represented by nonylphenoxy polyethylene glycol acrylate, and ethoxylated Examples include polyfunctional acrylates represented by bisphenol A diacrylate, ethoxylated bisphenol F diacrylate, and ethoxylated bisphenol S diacrylate. (3) As the functional group-containing acrylate, 2-hydroxyethyl acrylate, 2-hydroxymethacrylate, 2-
Alcohol type such as hydroxypropyl acrylate, hydroxydiethylene glycol methacrylate, butoxyhydroxypropyl acrylate, phenoxyhydroxypropyl acrylate, hydroxypropyl dimethacrylate.

Epoxy types such as diethylene glycol bis(hydroxypropyl acrylate) and propoxylated bisphenol A bis(hydroxypropyl acrylate), trimethylolpropane types such as hydroxypropylated trimethylolpropane triacrylate, and pentaerythritol types such as monohydroxypentaerythritol triacrylate. , allyl acrylate having an allyl group, glycidyl methacrylate having a glycidyl group,
Examples include ethyl monoacryloxyethyl phthalate and monoacryloxysuccinate having a carboxyl group. (4) Special acrylates include phosphorus type represented by acryloxyethoxydihydroxyphosphine oxide, bis(acryloxyethoxy)hydroxyphosphine oxide, and methacryloxyethoxydibutoxyphosphine oxide, and metal type represented by zinc diacrylate. . In addition, (5) vinyl type supernomers include pyrrolidone type represented by N-vinylpyrrolidone and vinyl acetate type represented by vinyl acetate.

Furthermore, the acrylic oligomer used in the present invention has one to several acryloyl groups, methacryloyl groups, allyl groups, or vinyl groups in one molecule.

It is a polymer with a repeating number of structural units of about 2 to 20. Specifically, epoxy acrylate, epoxy methacrylate, polyester acrylate, polyester methacrylate, urethane acrylate, urethane methacrylate, and polyol acrylate are obtained by acrylating epoxy resin, polyester resin, urethane resin, and polyol resin with acrylic acid or methacrylic acid.

Among these, which include polyol methacrylate and the like, epoxy acrylate and epoxy methacrylate are particularly preferably used. These photopolymerizable resins are appropriately selected from commercially available products so as to maintain flexibility in the B-stage state, and are used alone or in combination of two or more.

The thermosetting resin used in the present invention includes epoxy resin,
Examples include phenol resins, melamine resins, xylene resins, polyester resins, imide resins, and amine imide resins, among which epoxy resins are particularly preferably used.

These may be used alone or in combination of two or more. The thermosetting resin is used as a resin component together with the photopolymerizable resin, and commercially available products are appropriately selected and blended so as not to impair heat resistance and peel strength.

As the organic compound that acts as a reaction initiator used in the present invention, acetophenone-based, benzoin-based, benzophenone-based, thioxanthone-based organic compounds and the like are used. Examples of acetophenone-based organic compounds include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, jetoxyacetophenone, and 2-hydroxy-2-methyl-1-phenylpropane. -1~on, 1~
(4-isopropylphenyl)-2-hydroxy-2-
Methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-
hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone, 2-methyl-1-(4-
(Methylthio)phenyl]-2-morpholinopropane-
Examples include l-one and the like. Examples of the benzoin organic compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, and the like. Examples of benzophenone organic compounds include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone,
Examples include 4-benzoyl-4'-methyldiphenyl sulfide and 3,3'-dimethyl-4-methoxybenzophenone. Thioxanthone-based organic compounds include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, and 2,4-diethyl. Thioxanthone, 2,4
-diisopropylthioxanthone and the like. Other organic compounds include 1-phenyl-1,2-propanedione-2(0-ethoxycarbonyl)oxime,
2.4.6-trimethylbenzoyldiphenylphosphine oxide, methylphenylglyoxylate, benzyl, 9.10-phenanthrenequinone, camphorquinone, dibenzosuberone, 2-ethylanthraquinone,
4', 4''diethylisophthalophenone, 3.3',
4゜4'-tetra(t-butylperoxycarbonyl)
Examples include benzophenone. These acetophenone-based, benzoin-based, benzophenone-based, thioxanthone-based, and other organic compounds are used as reaction initiators for acrylic resins by ultraviolet irradiation, and can be used alone or in combination of two or more. The blending ratio of these organic compounds is 0.1 to 10 parts by weight based on 100 parts by weight of the resin component, which is the total amount of the photopolymerizable resin and the thermosetting resin. If the proportion is less than 0.1 parts by weight, the polymerization reaction of the photopolymerizable resin due to ultraviolet irradiation will not be completed, leaving tack on the adhesive surface in the B stage state, and if it exceeds 10 parts by weight, it will adversely affect heat resistance. However, these organic compounds are undesirable because they are economically disadvantageous and can be uniformly dissolved in the resin component.

An adhesive is obtained by mixing these three components and uniformly dissolving them. Difficult to dissolve and.

For insoluble resins, it is necessary to create a uniform resin solution by adding an organic solvent as necessary. Further, as the light source used when applying the adhesive to the copper foil and converting it into a B-stage, any conventionally known light source used for the same purpose can be used, such as a xenon lamp or a low-pressure mercury lamp.

High-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and fusion lamps are effective, and sunlight can also be used for curing.

As described above, the adhesive for copper foil of the present invention contains a photopolymerizable resin, a thermosetting resin, and an organic compound that acts as a reaction initiator. , a known polymerization inhibitor may be added and blended.

Further, if necessary, fillers such as magnesium hydroxide, calcium carbonate, silica, alumina, titanium oxide, etc. can be added and blended. Addition of these fillers improves the thixotropy of the adhesive.

Further, in the adhesive of the present invention, a hydrogen donor may be used as an auxiliary agent to promote radical generation of organic compounds such as acetophenone, benzoin, benzophenone, and thioxanthone based on ultraviolet rays, if necessary. The above hydrogen donors include triethanolamine, methyljetanolamine, triisopropanolamine, 4゜4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate. , (n-butoxy)ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, and the like.

The adhesive of the present invention can be easily made into an adhesive by uniformly dispersing or dissolving the above-mentioned components.

Examples are shown below, and in the following Examples and Comparative Examples, 1 part means part by weight.

Example 1 Photopolymerizable monomer resin, Kayarad TMPTA (manufactured by Nippon Kayaku Co., Ltd., trade name) 13 parts, photopolymerizable oligomer resin, Kayarad RM100I (manufactured by Nippon Kayaku Co., Ltd., trade name) 50 parts
1 part, epoxy resin, Epicoat 1001 (manufactured by Yuka Shell Co., Ltd., trade name) 25 parts, phenol resin, Pryobuen TD2131 (manufactured by Dainippon Ink Industries, Ltd., trade name) 1 part
Two parts were dissolved in a methyl ethyl ketone solvent, and two parts of an acetophenone organic compound, Irgacure 184 (trade name, manufactured by Ciba Geigy) were added to the resin component to prepare a resin solution with a concentration of 80%, which was used as an adhesive. This adhesive was applied to the treated surface of electrolytically treated copper foil with a thickness of 30 to 40 μm, air-dried, and then irradiated with ultraviolet rays of several thousand mJ/c1.
It was dried at 0° C. for 3 minutes and B-staged. Copper foil with adhesive applied to one side.

A prepreg formed by impregnating cellulose paper with a phenol resin was superimposed and heated and pressure-molded at 150° C. and 120 kg/cm” for 1 hour to produce a copper-clad laminate.

Example 2 In Example 1, instead of the photopolymerizable monomer resin Kayarad TMPTA, the same amount of 13
An adhesive was prepared and applied to copper foil in the same manner as in Example 1, except that a portion of the adhesive was used, and then a copper-clad laminate was manufactured.

Example 3 Photopolymerizable monomer resin, Kayarad TMPTA (manufactured by Nippon Kayaku Co., Ltd., trade name) 13 parts, photopolymerizable oligomer resin, Lipoxy S P-1509 (manufactured by Showa Kobunshi Co., Ltd., trade name) 5
0 parts of epoxy resin, Epotote YDCN701 (manufactured by Tobu Kasei Co., Ltd., trade name), 25 parts of phenol resin, 12 parts of Sumilight Resin PR-16382 (manufactured by Sumitomo Durets Co., Ltd., trade name) were mixed and dissolved, and further acetophenone-based organic A 100% resin solution was prepared by adding 2 parts of the compound Irgacure 907 (manufactured by Ciba Geigy, trade name) to the resin component, and used as an adhesive. Apply this adhesive to a thickness of 30 to 40
Coated on the treated surface of μ-island electrolytically treated copper foil, several thousand itJ/c
B-stage was obtained by irradiating ultraviolet rays of 1.0 m". The prepreg made by impregnating a paper base material made of copper foil and cellulose paper with the adhesive thus obtained on one side and impregnated with phenolic resin at 150°C and 120 kg/cm A copper-clad laminate was manufactured by heating and press-molding the material for 1 hour.

Example 4 An adhesive was prepared in the same manner as in Example 3 except that the same amount of 13 parts of the photopolymerizable monomer resin, Kayarad MANDA, was used instead of the photopolymerizable monomer resin, Kayarad TMPTA. Copper foil was coated using the same method, and then a copper-clad laminate was manufactured.

Example 5 An adhesive was prepared in the same manner as in Example 3, except that the amount of the acetophenone organic compound, Irgacure 184, was increased to 5 parts. A stretched laminate was manufactured.

Comparative Example 1 Polyvinyl butyral resin, Electrified Butyral 4000-
2 (manufactured by Denki Kagaku Co., Ltd., trade name) 60 parts, phenolic resin,
Maruzen Resin X (manufactured by Maruzen Oil Co., Ltd.)

20 parts of epoxy resin, Epicoat 828 (manufactured by Yuka Shell Co., Ltd., trade name) were dissolved in methyl ethyl ketone and xylene solvent, and further a Lewis acid boron trifluoride monoethylamine complex salt (manufactured by Hashimoto Kasei Kogyo Co., Ltd.) was dissolved in methyl ethyl ketone and xylene solvent. ,
(trade name) was added to the resin component to prepare a 20% resin solution, which was used as an adhesive. Apply this adhesive to a thickness of 30~
Apply 40 μl to the treated surface of electrolytically treated copper foil and air dry.

It was dried at 120°C for 10 minutes. A prepreg made by impregnating a paper base material made of copper foil and cellulose paper with the adhesive thus obtained on one side and impregnated with phenolic resin at 150°C.
A copper-clad laminate was manufactured by heating and pressing at 120 kg/c+a'' for 1 hour.

Regarding the copper-clad laminates manufactured in Examples 1 to 5 and Comparative Example 1, the peel strength and soldering heat resistance were evaluated by J I
Tested according to S-C Nee 6481.

The results are shown in Table 1.

(Left below) Table 1 As is clear from Table 1, the adhesive of the present invention has a high solids content and is excellent in adhesiveness, solvent resistance, and soldering heat resistance, confirming the effects of the present invention. It was done.

As explained above, the adhesive for copper foil of the present invention can be highly solidified by irradiating it with ultraviolet rays for B-stage formation, which improves its adhesive properties.

It has excellent solvent resistance and soldering heat resistance.

By using this, it is possible to reduce the area occupied by the apparatus used for B-stage of copper foil adhesive.

〔Effect of the invention〕

According to the present invention as described above, the following effects are achieved.

(1) Photopolymerizable resin polymerizes instantly when exposed to ultraviolet rays, so there is no need to create a temperature gradient in the drying oven unlike adhesives that are dried by heating, and B-stage adhesives can be achieved in a small equipment space. Moreover, unlike adhesives that are dried by heating, the low molecular weight materials of the adhesive raw materials will not condense in the drying oven and the surface of the copper foil will not be contaminated by the condensed matter falling.

(2) Photopolymerizable resins are divided into oligomers and monomers depending on their molecular weight, and thermosetting resins can be easily and uniformly dissolved, and the viscosity can be adjusted and applied by changing the ratio of monomers and oligomers. Select as appropriate, taking into account workability. Therefore, it is possible to make the adhesive highly solid. Furthermore, since the adhesive has a high solid content, adhesive costs can be reduced, and environmental pollution caused by solvent vapor and adverse effects on coating workers caused by solvent evaporation can be reduced.

(3) Since a photopolymerizable resin is used as the main raw material of the adhesive, an adhesive with excellent solvent properties (particularly halogenated organic solvents) can be obtained.

Claims (1)

[Claims] 1. Contains a photopolymerizable resin, a thermosetting resin, and an organic compound that acts as a reaction initiator, and the organic compound is contained in an amount of 0.0% per 100 parts by weight of the photopolymerizable resin + thermosetting resin. 1-10
Adhesive for copper foil containing parts by weight. 2. The adhesive for copper foil according to claim 1, wherein the photopolymerizable resin is a monomer having one or more acryloyl group, methacryloyl group, or vinyl group per molecule, or an acrylic oligomer alone or in a mixture of two or more types. agent. 3. Thermosetting resin is epoxy resin, phenol resin,
The adhesive for copper foil according to claim 1, which is made of melamine resin, xylene resin, polyester resin, imide resin, amine imide resin, etc., singly or in a mixture of two or more. 4. The adhesive for copper foil according to claim 1, wherein the organic compound acting as a reaction initiator is one or a mixture of two or more of acetophenone, benzoin, benzophenone, or thioxanthone organic compounds.