JPH10226019A - Adhesive-applied copper foil for paper base material phenol resin copper-clad laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide adhesive-applied copper foil for a paper base material phenol resin copper-clad laminated sheet obtained by using non-roughened copper foil not subjected to roughening treatment, not leaving copper particles in a phenol resin after etching when a paper base material phenol resin copper-clad laminated sheet is produced, easy in the formation of a circuit, having peeling strength equal to that obtained when roughened copper foil is used and excellent in solder heat resistance. SOLUTION: In an adhesive-applied copper foil for a paper base material phenol resin copper-clad laminated sheet obtained by providing an adhesive layer to non-roughened copper foil to which coupling agent treatment is applied, the adhesive layer consists of an adhesive layer wherein 1-49 pts.wt. of an epoxy resin is added to 100 pts.wt. of a polyvinyl acetal resin provided on the surface of copper foil and an adhesive layer wherein 50-200 pts.wt. of an epoxy resin is added to 100 pts.wt. of a polyvinyl acetal resin provided on the surface of the laminated sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copper foil with an adhesive for a paper-based phenolic resin-clad laminate used in the manufacture of printed wiring boards.

[0002]

2. Description of the Related Art A paper-based phenol resin copper-clad laminate is frequently used in electronic circuits of consumer electronic devices. This laminate is generally manufactured by heating and integrating a predetermined amount of kraft paper impregnated with a phenol resin and an electrolytic copper foil. Electrodeposited copper foil has two types of surfaces, a glossy surface and a matte surface, and is used by applying a polyvinyl acetal-based adhesive to a matt surface having large irregularities and suitable for bonding. Electrodeposited copper foil is produced by electrolysis of copper sulfate.However, sufficient adhesion is not obtained only by the irregularities formed during electrolysis, so fine copper particles are formed on the surface by roughening treatment. Used. Roughening treatment is difficult to control because electrolysis is performed at a high current density equal to or higher than the limit current density, which is an obstacle to manufacturing. Also, the copper particles formed by the roughening process are buried in the phenolic resin on the surface of the laminate,
When a circuit is formed, copper is likely to remain in the resin as residual copper after etching, which may impair the insulating properties. Therefore, it has been desired to use a non-roughened copper foil which is not subjected to a roughening treatment for the production of a paper-based phenolic resin-clad laminate.

[0003] Therefore, a relatively soft adhesive, for example, an adhesive obtained by adding a hexamethylene diisocyanate compound and a peroxide to polyvinyl butyral phenol, and a copper foil subjected to a surface treatment with a silane coupling agent are used. It is known that by using a roughened copper foil, the same peeling strength between a copper foil and a resin substrate as that obtained by using a current roughened copper foil can be obtained. But,
In paper-based phenolic copper-clad laminates, there is a problem that foam generated during immersion in a solder bath because a large amount of water generated during the curing process of the phenolic resin is present in the laminates. There is a problem that the foaming cannot be suppressed at the time of immersion in a solder bath because the peeling strength is not sufficient.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a copper foil with an adhesive using a non-roughened copper foil which is not subjected to a roughening treatment. sometimes,
No copper particles remain in the phenolic resin after etching, easy circuit formation, the same peeling strength as when using roughened copper foil, and excellent heat resistance to soldering. An object of the present invention is to provide a copper foil with a plate adhesive.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, two types of specific non-roughened copper foils having different compositions have been obtained. Suitable for paper-based phenolic copper-clad laminates with the same adhesive strength as copper foil with adhesive using a conventional roughened copper foil by applying two or more layers of adhesive The present inventors have found that a copper foil with an adhesive can be obtained, and have completed the present invention based on this finding.

That is, the present invention provides an adhesive copper foil for a paper-based phenolic copper-clad laminate obtained by providing an adhesive layer on a non-roughened copper foil subjected to a coupling agent treatment, wherein the adhesive layer is Polyvinyl acetal resin 100 provided on the copper foil side
An adhesive layer (1) containing 1 to 49 parts by weight of an epoxy resin in a weight part and an adhesive layer containing 50 to 200 parts by weight of an epoxy resin in 100 parts by weight of a polyvinyl acetal resin provided on the surface of the laminate ( The present invention provides a copper foil with an adhesive for a paper-based phenolic resin copper-clad laminate characterized by comprising 2).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As a non-roughened copper foil used in the present invention, an electrolytic copper foil or a rolled copper foil is used, and a secondary rough surface forming means such as electrolytic roughening, Those that have not been subjected to chemical etching, mechanical polishing, etc. are used. As the non-roughened copper foil, a copper foil preferably having a thickness of 12 μm to 105 μm, particularly an electrolytic copper foil having a thickness of 18 μm to 70 μm is suitably used. From the viewpoint of preventing oxidation of the copper foil surface and increasing the affinity for the coupling agent, it is preferable that the surface of the copper foil be subjected to a chromate treatment or a chromate treatment containing a zinc compound. Also,
Nickel or cobalt,
Alloy plating with zinc, molybdenum, or the like may be performed. By such alloy plating, characteristics such as heat resistance and chemical resistance can be improved.

[0008] The roughened copper foil used in the present invention has been subjected to a coupling agent treatment. For the coupling agent treatment, a part showing affinity for an inorganic compound and a part showing affinity for an organic compound in a molecule, such as various commercially available silane coupling agents and titanate-based coupling agents, are used. Can be used. Examples of the silane coupling agent include γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane. Ethoxysilane,
γ-mercaptopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane and the like. Further, a commercially available silane coupling agent primer such as X-12-413 manufactured by Shin-Etsu Chemical Co., Ltd. can also be used. These coupling agents may be used alone or in combination of two or more. Also,
It may be used together with a compound containing silicon such as water glass, polymethylsiloxane, tetraethoxysilane, and triethoxymethylsilane. These compounds are generally present at 0.1.
The treatment can be performed by forming a thin liquid film on the surface of the copper foil by dipping or showering as an aqueous solution in which 01 to 5.0 parts by weight is dissolved in 100 parts by weight of water, and drying it.

[0009] Among the two types of adhesives used as the adhesive for the adhesive layer, the adhesive used as the adhesive for the first adhesive layer provided on the copper foil side has a large elongation and an affinity with the coupling agent. Those with good properties are used. As such an adhesive, an adhesive obtained by mixing 1 to 49 parts by weight of an epoxy resin with 100 parts by weight of a polyvinyl acetal resin is used.

The polyvinyl acetal resin preferably has an average degree of polymerization of 2000 to 3500. The type of aldehyde used for acetalization and the degree of acetalization are not limited, but are selected from the balance between solubility and mechanical properties. Further, a carboxylic acid-modified product may be used.

As the epoxy resin, bisphenol A
A commonly used epoxy resin such as a mold and a cresol novolak type is preferably used, and a cresol novolak type epoxy resin is preferably used in view of solubility and mechanical properties. Amino resins can also be added. The amino resin is not particularly limited, but various melamine resins, benzoguanamine resins, and CTU-guanamine resins are suitably used.

Further, an isocyanate compound such as hexamethylene diisocyanate and its blocked isocyanate may be added to the adhesive. By the addition of the isocyanate compound, the formation of a strong chemical bond between the polyvinyl acetal resin and the coupling agent can be expected.

A solvent can be used for the adhesive. As the solvent, it is preferable to use a mixture having an appropriate solubility and volatility composed of alcohols, ketones and aromatic compounds.

The thickness of the first adhesive layer is 1 to 20 μm.
m is preferable. More preferably, 3 to 10 μm
And

On the other hand, the adhesive used as an adhesive for the second adhesive layer provided on the laminate surface side has an appropriate adhesive strength to the first adhesive layer and the respective surfaces of the laminate. It is necessary to have. In addition, the adhesive needs to have a sufficient strength to maintain a certain strength even at a high temperature during solder immersion and to suppress the evaporation of water remaining inside the laminate. As an adhesive having such properties, an epoxy resin is added in an amount of 50 to 100 parts by weight of a polyvinyl acetal resin.
An adhesive mixed with 200 parts by weight is used. Amino resins can also be added. The same polyvinyl acetal resin, epoxy resin and amino resin as described above are used.

The thickness of the second adhesive layer is 10 to 50.
It is preferably set to μm. More preferably, 15 to 40
μm.

If necessary, an adhesive layer having properties intermediate between the first adhesive layer and the second adhesive layer may be provided between the first adhesive layer and the second adhesive layer. May be provided.

In the present invention, by providing the two types of adhesive layers described above, it is possible to use a non-roughened copper foil to have the same peeling strength as using a roughened copper foil, and to improve the solder heat resistance. A copper foil with an adhesive for a paper-based phenolic resin-clad clad laminate, which is also excellent, can be obtained.

[0019]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

Production Example 1 100 parts by weight of polyvinyl butyral resin (Denki Chemical Industry Co., Ltd., product number 6000C) and cresol novolak type epoxy resin (Mitsui Petrochemical Industry Co., Ltd., product number N-6)
73) 25 parts by weight and 20 parts by weight of an amino resin (trade name: Delamine CTU-100 manufactured by Fuji Kasei Kogyo Co., Ltd.) are dissolved in a mixed solvent consisting of toluene, methyl ethyl ketone and methanol, and then an imidazole compound (a product of Shikoku Chemicals Co., Ltd.) No. 2E4MZCN) and 4 parts by weight of hexamethylene diisocyanate and 1 part by weight of adhesive solution A
I got The varnish had a solid content of 17% by weight.

Production Example 2 100 parts by weight of polyvinyl butyral resin (Denki Chemical Industry Co., Ltd., product number 6000C) and cresol novolak type epoxy resin (Mitsui Petrochemical Industry Co., Ltd., product number N-6)
73) 75 parts by weight and 25 parts by weight of an amino resin (trade name: Delamine CTU-100 manufactured by Fuji Kasei Kogyo Co., Ltd.) are dissolved in a mixed solvent consisting of toluene, methyl ethyl ketone and methanol, and then an imidazole compound (a product of Shikoku Chemicals Co., Ltd.) No. 2E4MZCN) was added to obtain an adhesive solution B. The varnish had a solid content of 19% by weight.

Production Example 3 An aqueous copper sulfate solution was electrolyzed to prepare a non-roughened copper foil having a thickness of 35 μm and a surface roughness (Ra) of 1.4 μm. Subsequently, the matte surface of the copper foil was subjected to chromate treatment at a current density of 0.15 A / dm ² in a treatment solution in which 2.2 g of sodium bichromate was dissolved in 1 liter of pure water.

Immediately after washing with water, γ-glycidoxypropyltrimethoxysilane (trade name: S-51, manufactured by Chisso Petrochemical)
0) 1 g of water glass and 0.5 g of water glass were dissolved in 1 liter of pure water for 10 seconds, and immersed in hot water at 80 ° C. for 1 minute to obtain a roughened copper foil.

Production Example 4 Prior to performing the chromate treatment on the copper foil of Production Example 3, a roughening treatment was performed by depositing fine copper particles with a high current density on a mat surface in an aqueous solution of copper sulfate. Further, a chromate treatment and a silane coupling agent treatment were performed in the same manner as in Production Example 3 to obtain a roughened copper foil. The surface roughness of this copper foil is Ra
Was 1.7 μm.

Example 1 The adhesive solution A of Production Example 1 was added to the non-roughened copper foil of Production Example 3 for 40 minutes.
After coating with a bar coater having a μm gap and leaving at room temperature for 10 minutes, drying was performed at 60 ° C. for 5 minutes and then at 120 ° C. for 5 minutes. The thickness of the coating film measured by a micrometer before and after coating was 5 μm. Then 180
Adhesive solution B of Production Example 2 using a bar coater with a μm gap
And dried in the same manner. Next, it was dried at 160 ° C. for 2 minutes to obtain a copper foil with an adhesive. The thickness of the coating film determined by measuring the thickness before and after coating with a micrometer was 25 μm, and the total thickness of the adhesive A and the adhesive B was 30 μm.

[0026] with the paper substrate phenolic resin substrate (Sumitomo Bakelite Industry Co., Ltd. Product No. PI-N5) 8 sheets of this adhesive thickness 0.2mm the coated copper foil agent, temperature 170 ° C., at a pressure 140 kgf / cm ² 60 The resin was cured by heating for minutes, to give a copper-clad laminate.

Comparative Example 1 The adhesive solution A of Production Example 1 was added to the non-roughened copper foil of Production Example 3 for 25 times.
After coating with a bar coater having a gap of 0 μm and leaving it at room temperature for 10 minutes, it is dried at 60 ° C. for 5 minutes, then at 120 ° C. for 5 minutes, then at 120 ° C. for 5 minutes, and then at 160 ° C. for 2 minutes, and then attached with an adhesive. Copper foil was used. The thickness of the coating film determined by measuring the thickness before and after coating with a micrometer was 31 μm.

This copper foil with adhesive was made into a copper-clad laminate in the same manner as in Example 1.

Comparative Example 2 A copper-clad laminate was prepared in the same manner as in Comparative Example 1 except that adhesive solution B was used in place of adhesive solution A in Comparative Example 1, and the coating was performed with a bar coater having a gap of 200 μm. In addition, the thickness of the adhesive coating film of the copper foil with an adhesive was 29 μm.

Comparative Example 3 A commercial adhesive (product number VP-71: polyvinyl acetal resin-based adhesive) was used in place of the adhesive solution A of Comparative Example 1 and coated with a 210 μm gap bar coater. A copper-clad laminate was produced in the same manner as in Comparative Example 1 except for the above. The thickness of the adhesive coating film of the copper foil with the adhesive is 30.
μm.

Comparative Example 4 A copper-clad laminate was produced in the same manner as in Comparative Example 1 except that the roughened copper foil of Production Example 4 was used instead of the non-roughened copper foil of Comparative Example 3. In addition, the thickness of the adhesive coating film of the copper foil with an adhesive was 31 μm.

Table 1 shows the results of evaluating the copper-clad laminates of Example 1 and Comparative Examples 1 to 4 in accordance with JIS C6481. However, the peeling strength was measured with a line width of 1
mm.

[0033]

[Table 1] From the results in Table 1, the copper foil with adhesive using the non-roughened copper foil of Example 1 is excellent in the peeling strength and the solder heat resistance, and compared to the conventional copper foil with adhesive using the roughened copper foil. It is clear that they have comparable properties.

[0034]

According to the present invention, a paper-based phenolic resin-based copper-clad laminate adhesive is obtained by applying a specific adhesive having a different composition to two or more layers on a roughened copper foil treated with a coupling agent according to the present invention. Copper foil has properties comparable to conventional adhesive-coated copper foil using roughened copper foil, and is excellent in productivity because there is no need to perform roughening treatment which has many problems in the manufacturing process of copper foil, Since there are no roughened particles embedded in the phenol resin of the base material that hinder the etching, the printed wiring board has excellent quality reliability.

Continuation of front page (72) Inventor Naka Yokono 1226 Shimoedashiri, Shimodate-shi, Ibaraki Pref.

Claims (1)

[Claims] 1. A copper foil with an adhesive for a paper-based phenolic copper-clad laminate obtained by providing an adhesive layer on a non-roughened copper foil that has been subjected to a coupling agent treatment, wherein the adhesive layer is on the copper foil side. An adhesive layer containing 1 to 49 parts by weight of an epoxy resin in 100 parts by weight of a polyvinyl acetal resin provided in Example 1 and 50 to 200 parts by weight of an epoxy resin were contained in 100 parts by weight of a polyvinyl acetal resin provided on the laminate surface side. A copper foil with an adhesive for a paper-based phenolic copper-clad laminate, comprising an adhesive layer.