JPS62241983A - Adhesive for copper foil - Google Patents

Abstract

PURPOSE:To provide the titled adhesive which is excellent in adhesion, soldering heat resistance and storage stability, can be easily produced and applied to a wide variety of resins and which comprises a polyvinyl acetal resin, a thermosetting resin, and a particular sulfur compd. CONSTITUTION:0.1-10pts.wt. sulfur compd. of thiazole, sulfenamide type or thiuram type (C) (e.g., N-cyclohexyl-2-benzothiazolylsulfenamide) is incorporated in 100pts.wt. in total of a polyvinyl acetal resin (A) selected from among a polyvinyl formal resin and a polyvinyl butyral resin having a degree of polymerization of 1,000-2,000 and a degree of butyralization of 60-65mol% and at least one thermosetting resin (B) selected from among an epoxy resin, a phenolic resin, a poly-p-vinyl phenolic resin, a melamine resin, a xylene resin, a satd. polyester resin, and a thermosetting acrylic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention 1 (Industrial Application Field) The present invention relates to an adhesive for copper foil that has excellent adhesive properties, soldering heat resistance, and storage stability.

(Prior art) In recent years, with the development of the electronic equipment industry, the demand for printed circuit boards has been increasing year by year.However, as electronic equipment becomes denser, lighter, thinner, and smaller, the distance between the lines of printed circuit boards is gradually decreasing. It's getting narrower. In addition, for consumer electronics, from a safety standpoint, copper-clad laminates must be immersed in a molten solder bath to avoid blisters, holes to be drilled without hindering machining, and if plating is required, plating chemicals must be used. It is necessary that it not be affected by

As these usage and processing conditions become more and more severe, stronger bonding strength between the copper foil and the base material of copper-clad laminates is strongly required as one aspect of board reliability. There is a demand for the development of an adhesive that satisfies this requirement.

(Problems to be Solved by the Invention) In order to increase the adhesive strength between the copper foil and the base material, the composition of the adhesive includes a diene rubber having a carboxyl group and an epoxy resin, or a modified resin having a hydroxyl group. There is a known method of adhering dissimilar materials, such as copper foil and a base material, by adding resin, etc., but these methods are based on carboxyl groups,
Although the hydroxyl group has the effect of increasing the wettability of the adhesive to both materials, it has the disadvantage that it has little effect on actively bringing out the properties of copper. To improve this, there is a method of adding a thiol compound and actively forming a complex on the copper surface by the action of the mercapto group of the compound, or modifying the copper surface to make it lipophilic.

However, when a mercapto group is included in an adhesive resin, it easily interacts with other functional groups in the resin, resulting in a loss of storage stability of the adhesive and a significant decrease in adhesive strength after long-term storage. There is a drawback that it decreases. There is also a method of adding a 2-substituted-4,6-cythiol-5ys-triazine derivative as a thiol compound, but since this derivative has limited solubility in resins and solvents, it is necessary to treat the copper foil with this derivative in advance. Since it is necessary to etch the adhesive and apply the adhesive, the process is complicated and costly, and it also has the disadvantage that it cannot be applied to a wide range of resin-based adhesives.

The present invention solves the above-mentioned drawbacks, and improves adhesiveness, solder heat resistance,
It has excellent storage stability, is easy to make, and does not require high costs.
The purpose of the present invention is to provide a copper foil adhesive that can be applied to a wide range of resin systems.

[Structure of the invention] (Means and effects for solving the problem) The present inventors
As a result of intensive studies to achieve the above objectives, we found that the addition of thiazole-based, sulfenamide-based, or thiuram-based sulfur compounds improves adhesive strength, soldering heat resistance, has good storage stability, and is economical. This discovery led to the completion of the present invention. That is, the present invention includes (A) a polyvinyl acetal resin, (B) a thermosetting resin, and (C) a thiazole-based, sulfenamide-based, or thiuram-based sulfur compound as essential components, and the (C) sulfur compound as a resin. The adhesive for copper foil is characterized in that it is blended in an amount of 0.1 to 10 parts by weight based on 1100 parts by weight of components [(A) + (B).

Examples of the polyvinyl acetal resin (A) used in the present invention include polyvinyl formal am obtained by acetalizing polyvinyl alcohol with formaldehyde or butyraldehyde, polyvinyl butyral resin, and the like.
Among these, polyvinyl butyral resin is particularly preferably used.

The degree of butyralization and degree of polymerization of polyvinyl butyral resin are not particularly limited, but the degree of butyralization is 60 to 65 mol%.
, those having a degree of polymerization of 1000 to 2000 exhibit the best properties. Specific oils and fats include S-LEC BX-1 (manufactured by Sekisui Chemical Co., Ltd., trade name), Denka Butyral 4000-
2 (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name), Butover 8-72
A (manufactured by Shawinigan Company, trade name) and the like.
Similarly, a wide variety of commercially available polyvinyl formal resins are used, and the resins are appropriately selected from these. These resins may be used alone or in a mixture of two or more.

Examples of the thermosetting resin (B) used in the present invention include epoxy resin, phenol resin, polyparavinylphenol resin, melamine resin, xylene resin, saturated polyester resin, thermosetting acrylic resin, etc. Use a mixture of two or more. Thermosetting resin is (
It is combined with the polyvinyl acetal resin of A) to form a resin component, and commercially available products are appropriately selected and blended so as not to impair the adhesive strength, flexibility, and heat resistance of the present invention.

As the sulfur compound (C) used in the present invention, a thiazole-based, sulfenamide-based, or thiuram-based sulfur compound is used. As thiazole compounds,
Dibenzothiazyl disulfide, zinc salt of 2-mercaptobenzothiazole, 2-(2',4'-dinitrophenylthio)benzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(N,N
'-diethylthiocarbamoylthio)benzothiazole, 2-(4'-morpholinodithio)benzothiazole, and the like.

As a sulfenamide compound, N-cyclobekyl
Sil-2-benzothiazolylsulfenamide, N,N
-dicyclohexyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide, and the like. Examples of thiuram compounds include tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, tetraethylthiuram monosulfide, tetrabutylthiuram monosulfide, dipentamethylenethiuram tetrasulfide, and the like. These thiazole-based, sulfenamide-based, and thiuram-based sulfur compounds can be used alone or in combination of two or more. The blending ratio of the sulfur compound is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the resin component, which is the total amount of the polyvinyl acetal resin and the thermosetting resin.
When the proportion is less than 0.1 part by weight, the coating effect on the copper surface is small and the adhesive strength is weak, and when it exceeds 10 parts by weight, the adhesive strength cannot be further improved and it is not preferable because it is economically disadvantageous. Thiazole-based, sulfenamide-based, and thiuram-based compounds can be easily and uniformly dissolved in resin components, and do not directly form a thiol structure, so they have storage stability even when used as adhesives. These compounds blended into the adhesive cause radical cleavage reactions or ionic reactions between sulfur atoms, between sulfur atoms, or between sulfur atoms and nitrogen atoms due to the heat applied when the copper foil and base material are laminated. The activated species generated through the cleavage reaction directly attack the steel foil surface and form lipophilic MS. The mechanism for improving adhesive strength is thought to be that the adhesive strength of the adhesive to the body side increases significantly. The lipophilic coating layer formed at the interface between the copper foil and the adhesive also works to prevent water molecules from entering, so using this adhesive improves adhesive strength, heat resistance, and moisture resistance. It is.

The copper foil adhesive of the present invention includes polyvinyl acetal resin,
Contains a thermosetting resin and a sulfur compound, but as long as it does not adversely affect the effects of the present invention, kaolin, clay,
Fillers and pigments such as talc, calcium carbonate, silica, alumina, and titanium oxide can be added and blended. Furthermore, ketone, ester, aromatic, and alcohol solvents are widely used in the adhesive of the present invention, and are appropriately selected in consideration of the solubility of the resin component, the sulfur compound, and the coating workability.

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

(Examples) Next, the present invention will be specifically explained by examples, but the present invention is not limited by these examples.

In Examples and Comparative Examples, "parts" means "parts by weight."

Example 1 63 parts of polyvinyl butyral resin ESLETSUKU BX-1 (manufactured by Tsukiki Kagaku Kogyo Co., Ltd., trade name), 9 parts of butylated melamine resin BECKAMIN J-820-60 (manufactured by Dainippon Ink Chemical Co., Ltd., trade name), epoxy resin Epicote 1001 (
11 parts of phenolic resin Veraiohen 5010 (manufactured by Nippon Reichhold Co., Ltd., trade name) were dissolved in a mixed solvent of methyl ethyl ketone and ethyl alcohol, and then a thiazole-based sulfur compound dibenzothiazyl Sulfide, Tsukusera DM (
2 (manufactured by Iriuchi Shinko Kagaku Kogyo Co., Ltd., product name) for the resin component.
．． A resin solution with a concentration of 20% was prepared by adding 0 parts to prepare an adhesive. This adhesive was applied to the treated surface of an electrolytically treated copper foil having a thickness of 30 to 40 μm, air-dried, and then dried at 120° C. for 10 minutes. Copper foil coated with adhesive on one side and prepreg made of cellulose paper impregnated with phenolic resin are superimposed and heated and pressed at 150°C and 130K (II/Cl for 21 hours) to form a copper-clad laminate. The board was manufactured.

Example 2 In Example 1, the sulfenamide-based sulfur compound N-cyclohexyl-2-benzothiazolylsulfenamide, Tsuxela CZ-P was used instead of the thiazole-based sulfur compound dibenzothiazyl sulfide Tsuxela DM.
(manufactured by Iriuchi Shinko Kagaku Kogyo Co., Ltd., trade name) was used in the same manner as in Example 1, except that 2.0 parts of the adhesive was used, and the adhesive was prepared and applied to copper foil, and then a copper-clad laminate was manufactured. did.

Example 3 In Example 1, the thiuram-based sulfur compound tetrabutylthiuram disulfide, instead of the thiazole-based sulfur compound dibenzothiazyl sulfide and Tsuksela DM,
Tsukusera TBT (manufactured by Iriuchi Shinko Kagaku Kogyo Co., Ltd., product name)
An adhesive was prepared in the same manner as in Example 1, except that 2.0 parts of the same method was used, and the adhesive was applied to copper foil to obtain a copper-clad laminate.

Example 4 Polyvinyl butyral resin electrified Butyral 4000-2
(manufactured by Denki Kagaku Kogyo Co., Ltd., trade name) 36 parts, polyvinyl formal resin Vinylec E (manufactured by Chisso Co., Ltd., trade name) 9
and polyparavinylphenol resin Maruzen Resin M
(manufactured by Maruzen Oil Co., Ltd., trade name) 22 parts, epoxy resin Araldite ECN-1280 (manufactured by Ciba Geigy Co., Ltd., trade name)
After dissolving 22 parts of xylene resin dicanol H (manufactured by Mitsubishi Gas Chemical Industries, Ltd., trade name) in a mixed solvent of methyl ethyl ketone, toluene and isobutanol, the sulfenamide compound Tsuxerer: c z -p (former) was dissolved. A resin solution having a concentration of 20% was prepared by adding 2.0 parts of the following to the resin component, and used as an adhesive. Apply this adhesive to a thickness of 30~
Apply to the treated surface of electrolytically treated copper foil with 40μ haze, and after air drying
It was dried at 0°C for 10 minutes. The thus obtained copper foil coated with adhesive on one side and the prepreg made by impregnating the paper base material made of cellulose paper with phenolic resin were heated to 150°C.
, 130k (J/C112, open at 1 o'clock) to produce a copper-clad laminate.

Example 5 An adhesive was prepared in the same manner as in Example 2 except that the content of the sulfenamide-based sulfur compound Tsuxela CZ-P (described above) was reduced to 0.5 parts.
Copper foil was coated, and then copper-clad laminates were produced.

Example 6 In Example 2, the adhesive was made from W4 in the same manner as in Example 2 except that the amount of the sulfenamide-based sulfur compound Tsuxela CZ-P (described above) was increased to 5.0 parts. Copper foil was coated, and then copper-clad laminates were produced.

Example 7 An adhesive was prepared in the same manner as in Example 2 except that the amount of the sulfenamide-based sulfur compound Tsuxela CZ-P (described above) was increased to 9.0 parts. A foil was coated and then a copper clad laminate was produced.

Comparative Example 1 An adhesive was prepared in the same manner as in Example 1 except for omitting the thiazole-based sulfur compound Tsukusela〇M (described above) as a compounding ingredient, and applied to copper foil, and then coated with copper foil. A laminate was manufactured.

Comparative Example 2 An adhesive was prepared in the same manner as in Example 4 except that the sulfenamide-based sulfur compound Tsuxela CZ-P (mentioned above) was deleted, and the adhesive was applied to copper foil. Next, a copper-clad laminate was manufactured.

The copper-clad laminates manufactured in Examples 1 to 7 and Comparative Examples 1 to 2 were tested for peel strength, solder heat resistance, and electrical properties according to JIS-C-6481.

The results are shown in Table 1.

As is clear from Table 1, the adhesive of the present invention has excellent adhesive properties, soldering heat resistance, and storage stability, and the effects of the present invention were confirmed.

[Effects of the Invention] As explained above, the adhesive for copper foil of the present invention has improved adhesiveness, soldering heat resistance, and storage stability by incorporating a thiazole-based, sulfenamide-based, or thiuram-based sulfur compound. Copper-clad laminates using this material do not erode or blister even when immersed in plating baths or solder baths, making it possible to obtain highly reliable electronic devices.

Claims (1)

[Scope of Claims] 1 (A) a polyvinyl acetal resin, (B) a thermosetting resin, and (C) a thiazole-based, sulfenamide-based, or thiuram-based sulfur compound as essential components; The resin component [(
A) + (B)] 0.1 to 10 parts by weight per 100 parts by weight of an adhesive for copper foil. 2. The adhesive for copper foil according to claim 1, wherein the polyvinyl acetal resin is a polyvinyl formal resin or a polyvinyl butyral resin. 3 The thermosetting resin is an epoxy resin, a phenolic resin,
The adhesive for copper foil according to claim 1 or 2, which is polyparavinylphenol resin, melamine resin, xylene resin, saturated polyester resin, or thermosetting acrylic resin.