JPS6015654B2 - Adhesion method for chromate treated layer of copper foil and resin base material - Google Patents

Description

[Detailed Description of the Invention] This invention provides a method for combining a chromate-treated layer of copper foil and a resin base material.
This invention relates to a new method for achieving strong adhesion.

Specifically, the chromate treatment layer formed on the rough surface side of the copper foil is formed using the general formula YRSiX3 (where Y is a functional group that reacts with a polymer, and R is a chain connecting Y and a silicon atom). A bonding group containing a cyclic or cyclic hydrocarbon; x represents an organic or inorganic hydrolyzable group bonded to a silicon atom.

) After treatment with a silane coupling agent solution represented by the above formula, the silane coupling agent of the above general formula is added to the chromate treatment layer formed on the rough side of the copper foil, or by adhering this to the resin base layer. The present invention relates to a method of bonding a chromate-treated layer of steel foil and a resin base material, in which the adhesive layer is formed and then bonded to the resin base material. Now, in order to increase the adhesion between the copper foil and the resin base material, copper-clad laminates for printed circuits are made by roughening the bonding surface of the copper foil obtained by electrolysis or rolling, using electrolysis. This has been carried out by forming a large number of dendrites on the surface and then bonding the dendrites to a resin base material.

More specifically, when using a glass-epoxy resin base material, the copper foil rough surface treated as described above and the base material are laminated by heating and pressurizing, and when using a phenolic resin base material, Phenol resin adhesive is applied to the roughened steel foil surface, layered with Motomura, heated and pressed to form horizontal layers.
Ta. It is known that the adhesive force between the copper foil and the base material when bonded by such a method improves as the surface of the steel foil becomes rougher. However, if the copper surface is made too rough, a part of the roughened surface of the steel foil will remain on the exposed base material surface during etching after the laminate is manufactured, resulting in the formation of laminate stains, which is a major drawback. . The above drawbacks have been prevented by performing a complicated process of coating metallic zinc on the plated steel foil having the dendritic structure, and by performing various controls and adjustments regarding the electrolytic rating and electrolytic method. The present invention provides a method for firmly adhering a chromate-treated layer of copper foil and a resin base layer by eliminating the staining and complicated steps found in the above-mentioned secondary method.

The present inventors have discovered that the conventional bonding method between copper foil and resin base material is
Focusing on the physical means of simply creating dendrites on the copper foil surface, we developed a chemical method instead, that is, a chemical agent that acts as a chemical barrier between the steel foil and the resin. We thought that adhesion could be significantly improved by intervening adhesive agents, and we have been studying the chemicals to be used. As a result, it was confirmed through numerous experiments that interposing the known silane coupling agent with the general formula YRSiX3 between the chromate treatment layer of copper foil and the resin base material is extremely effective for this type of purpose. did it. Here, Y in the formula is a functional group that reacts with a polymer, such as pinyl, amino, diamino, chloro, epoxy, mercapto, methacryloxy, etc. As a polymer that can react with Y, , phenol, epoxy, acrylic, alkyd, vinyl chloride, polyester, polyurethane, and butyl rubber, nitrile rubber, nitrocellulose, etc. Further, R is a bonding group containing a circular or cyclic hydrocarbon that connects Y and a silicon atom, and X is a hydrolyzable group that bonds to a silicon atom, such as chloro, methoxy, methoxyshetoxy, etc. be. The mechanism by which the above-mentioned lucky silane coupling agent improves the adhesion between the chromate-treated layer of copper foil and the resin base material has not yet been fully investigated, but Y in the general formula It is thought that it contributes to the improvement of adhesion through actions such as improvement of surface roughness, improvement of compatibility, and formation of covalent bonds. When subjected to the reaction, silanol and HX are formed as shown in the following formula, and this reaction product is thought to provide adhesive strength to the chromate-treated layer of the copper foil.

YRSi did.

[1} The chromate treatment layer formed on the rough side of the steel foil is treated with the silane coupling agent, and YRS is applied to the surface.
A thin film of iX3 is formed.

An adhesive layer containing the silane coupling agent is formed on the chromate layer formed on the dregs side of the '21 copper foil.

Then, various experiments were repeated using the above method, and the effects were recognized, so the present invention was completed based on the results of these experiments.

If the method of the present invention is applied to bonding the chromate-treated layer of copper foil and the resin base material, there is no need to perform harsh roughening treatment on the copper foil as in the past, and deposits on the cathode surface by electrolysis can be avoided. After roughening the surface of the steel foil or the surface to an extent that no staining occurs, chromate treatment is performed on the rough side of the steel foil, and the surface is treated with the silane cobbling agent, or
Alternatively, by forming an adhesive layer impregnated with a silane coupling agent on the chromate-treated surface and adhering it to the resin base material, the adhesion to the resin base material can be strengthened.

Therefore, the present invention can be said to provide an adhesive method that is effective for manufacturing printed circuits and the like. Next, Table 1 summarizes typical examples of silane coupling agents that can be used in the present invention and their characteristics. Table 1 The present invention involves treating a chromate treatment layer formed on the rough surface side of a steel foil using the above-mentioned silane coupling agent, and then bonding this to a resin base material, or After forming an adhesive layer containing a silane coupling agent on the chromate-treated layer on the side, it is bonded to the resin base material.

The concentration of the silane coupling agent for the chromate layer treatment of the copper foil is 0.001 to 5% by weight, preferably 0.
．． It is a 1-3% by weight solution. In addition, when providing an adhesive layer, 0.001 to 5
Adhesion is performed by adding or impregnating a silane coupling agent in an amount of 0.1 to 3% by weight, preferably 0.1 to 3% by weight. The reason for setting a limit on the amount of silane coupling agent to be used is that even if an amount is used below this range, or even if it is used in an amount above this range, a decrease in adhesive strength is observed during adhesion. This is because the.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 After exposing a copper foil with a thickness of 32 mm on the surface of a titanium cathode using a known acidic sulfuric acid steel plating bath, it was peeled off from the cathode, washed with water, and its roughness was removed. Na2Cr207. whose surface side was adjusted to pH 3-5 was heated to a temperature of 2 in a solution of 20.
0, treated for 1 minute at a cathodic current density IA/d,
A chromate layer was formed on the rough surface of the copper foil by washing with water and drying.

Next, this sample was diluted by adding water to an ethyl alcohol solution of y-glycidoxypropyltrimethoxysilane, and its pH was adjusted to 4.5 to 5.0 with acetic acid, and the concentration was adjusted to 0.01% by weight. 0.1% by weight and 3. Each sample was immersed in three types of solutions adjusted to a weight percent of The chromate-treated surface of the piece was laminated with a glass-epoxy resin base material and dried for 30 minutes at 1590° C. and 100 k9' pressure to produce a 250 x 250 x 2-wall copper-clad laminate. At the same time, for comparison, steel clad laminate pieces with the same dimensions were prepared under the same conditions from a copper foil (blank) that was not treated with a silane coupling agent, and the peel strength and resistance to cyanide deterioration of these test pieces were investigated. rate (deterioration rate of peel strength after soaking a copper-clad laminate specimen in a 10% KCN aqueous solution at 70°C for 3 minutes) and hydrochloric acid resistance (
A copper-clad laminate specimen was placed in an aqueous solution of reagent hydrochloric acid:water = 1:1.
This is the deterioration rate of peel strength after dipping for 1 hour at room temperature. ) was measured. The results are shown in Table 2. Table 2Table 2
After applying a known chromate treatment to the rough side of the copper foil and then treating it with a silane coupling agent, the peel strength, cyanide deterioration rate, and hydrochloric acid resistance of the copper foil were significantly lower than that of a blank copper foil. It can be seen that the yam quality was also excellent in the case of , and the effect was remarkable.

In addition, if the concentration of the silane coupling agent is 0.001% by weight or less or 5% by weight or more, the peel strength will be reduced by 0.3 to 0.5 k9/ky compared to the listed one in either case. This was experimentally confirmed. Therefore, the concentration of the silane coupling agent used in the treatment is suitably in the range of 0.001 to 5% by weight. For reference, as in Example 1, a 32y thick copper foil was deposited on the titanium cathode surface, then peeled off from the cathode and washed with water, and the rough side of the foil was subjected to chromate treatment. After treating the silane coupling agent solution under the same conditions as described in Example 1, the rough side of each specimen was stacked on a glass-epoxy resin base material and treated at 155°C and a pressure of 100k9/cm. A 250 x 250 x 2-rib copper-clad laminate was prototyped. At the same time, steel-clad laminates (blanks) not treated with a silane coupling agent were also produced, and the same tests as described in Example 1 were conducted on these trial steel-clad laminates. The results are shown in Table 3. Table 3 From Table 3, it can be seen that even when the rough side of the copper foil is treated with a silane coupling agent without chromate treatment, properties such as peel strength are improved compared to a blank. The properties are inferior to those of Example 1, which was treated with chromate on the surface side.

That is, it can be seen that by applying the chromate treatment, the adhesion between the rough surface side of the copper foil and the resin base layer is made even stronger. Example 2 The rough side of the 32-piece copper foil obtained in the same manner as in Example 1 was coated in a copper-plated coating consisting of CuS04, 9th, 20th, 100' and day 2, S04, 50'. After roughening to the extent that stain does not occur under the conditions of a maximum temperature of 20°C and a cathode current density of 3 to 5 A'd, the surface is subjected to chromate treatment under the same conditions as described in Example 1, After further treatment with a silane coupling agent solution under the same conditions as in Example 1, the chromate-treated surface of each specimen was placed on a glass to epoxy resin base material at 155°C and a pressure of 10°C.
A copper-clad laminate with a size of 250 x 250 x 2 was fabricated as a prototype.

At the same time, copper-clad laminates (blanks) not treated with a silane coupling agent were also produced, and tests similar to those described in Example 1 were conducted on these copper-clad laminates. The results are shown in Table 4. Table 4 From Table 4, it can be seen that the properties of the copper foil are significantly improved by treatment with the silane coupling agent liquid.

In other words, it has been found that the roughening treatment of steel foil does not require harsh treatment that may cause staining, as is the case with secondary steel foils. In addition, the silane coupling agent liquid concentration is 0.001% by weight.
It has been experimentally found that when the amount is less than 5% by weight and more than 5% by weight, the peel strength is lowered by about 0.5 [9' skin] than the stated value. Example 3 After performing roughening treatment and chromate treatment on the rough side of a copper foil with a thickness of 32 cm in the same manner as described in Example 2, the chromate treatment side of the copper foil was preliminarily treated with a solid content of 18 % of phenolic resin adhesive, y-methacryloxypropyl trimethoxysilane, which is a silane cobbling agent, was added to 0.01% and 0.1% by weight of the solid content of the adhesive, respectively.
After each of three types of adhesive containing 3% was applied, the volatile matter in the adhesive was removed by drying to form an adhesive layer with a thickness of 30 peaks.

The adhesive layer is then overlapped with a phenolic resin base material,
Lamination was carried out in the same manner as described in Example 1, and 250×
A 250x2 copper clad laminate was prototyped. The properties of this prototype steel clad laminate were measured in the same manner as described in Example 1, and are shown in Table 5 in comparison with those not treated with a silane coupling agent (blank). Table 5 It is clear from Table 5 that the adhesive strength between the copper foil and the resin base material can be significantly improved by using an adhesive containing a silane coupling agent.

Claims (1)

[Claims] 1. When adhering the chromate-treated layer of copper foil and the resin base material, the chromate-treated layer formed on the rough side of the copper foil is formed using the general formula YRSiX_3 (where Y is a polymer A functional group that reacts with a substance, R is a bonding group containing a chain or cyclic hydrocarbon that connects Y and a silicon atom, and X represents an organic or inorganic hydrolyzable group bonded to a silicon atom. ) After treatment with a silane coupling agent solution represented by the above formula and adhering it to a resin base material, or after forming an adhesive layer impregnated with the silane coupling agent represented by the above general formula on the chromate treatment layer, A method for adhering a chromate-treated layer of copper foil and a resin base material, the method comprising adhering the chromate-treated layer of copper foil to the resin base material. 2. The chromate treatment layer formed on the rough side of the copper foil is coated with 0.0% of the silane coupling agent represented by the general formula above.
2. The adhesive method according to claim 1, wherein the adhesive is treated with a 01 to 5% by weight solution and then adhered to a resin base material. 3 After providing an adhesive layer on the chromate treatment layer formed on the rough side of the copper foil, in which 0.001 to 5% by weight of the silane coupling agent represented by the above general formula is added to the solid content of the adhesive. , which is bonded to a resin base material.
Adhesion method described in section.