JPS6233779A - Adhesive for electroless plating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Fields] The present invention relates to an adhesive for electroless plating that forms an adhesive layer between an electroless plating film and an insulating substrate to be plated, particularly as a vulcanizing agent. An adhesive for electroless plating that does not contain sulfur or sulfur compounds.

[Prior Art] Conventionally, in a technique for manufacturing a non-contact substrate using electroless plating, an adhesive layer containing a rubber component was provided between an electroless plating film and an insulating substrate.

This rubber component greatly helps in improving adhesion, but in order to maintain the heat resistance and thermal shock resistance of the adhesive layer, it is necessary to add sulfur to this adhesive and vulcanize the rubber.

[Problems to be Solved by the Invention] However, unreacted sulfur added as a vulcanizing agent often causes undeposited plating.

As is well known, when sulfur is used as a vulcanizing agent and vulcanization is carried out at normal vulcanization temperatures, unreacted sulfur always remains, so if an adhesive containing sulfur is used, the plating may not be deposited on the pattern area. The occurrence of defects was unavoidable. In addition, methods such as increasing the vulcanization temperature have been used to avoid leaving unvulcanized components, or else the substrate becomes brittle. Another drawback was that unreacted sulfur eluted and contaminated the plating solution.

The present invention was made in view of the above-mentioned problems, and its purpose is to provide a non-sulfur-free material that has excellent heat resistance and thermal shock resistance, and also has durability due to its rubber component. An object of the present invention is to provide an adhesive for electrolytic plating.

[Means for Solving the Problems] The above objects of the present invention are achieved by an adhesive for electroless plating that does not contain sulfur and contains a thermosetting resin, rubber, and metal oxide as constituent components.

The constituent components of the present invention are as follows.

That is, the rubber component contained in the adhesive for electroless plating of the present invention is one that is contained in conventional adhesives, and both synthetic rubber and natural rubber can be used, but acrylonitrile butadiene rubber, chloroprene rubber, and isoprene rubber can be used. ,
Synthetic rubbers such as styrene-butadiene rubber are preferred, and acrylonitrile-butadiene rubber is most preferred in terms of close contact.

Further, the metal oxide contained in the adhesive for electroless plating of the present invention is zinc white, magnesium oxide, etc., and is used to vulcanize the above-mentioned rubber component.

As the thermosetting resin contained in the adhesive for electroless plating of the present invention, a heat condensation type phenol resin is used, but a novolac type phenol resin with a dense network structure, more specifically, a crosslinking agent is added. Novolac type phenolic resins containing an effective amount of methylol groups are preferred, as they are sufficiently heat-cured even without heat-curing and have good heat resistance after curing.

The content of the above constituent components is the sum of resin and rubber 10.

When expressed as parts by weight, the amount of thermosetting resin is preferably 30 to 80 parts by weight. If the amount of this thermosetting resin is less than 30 M parts, the heat resistance will decrease, and if it exceeds 80 parts by weight, the beer strength will decrease. In addition, the metal oxide is 0.5 to bit part when the sum of resin and rubber is 100 parts by weight,
Preferably it is 1 to 2.5 parts by weight.

In addition, the adhesive for electroless plating of the present invention includes carbonates of alkaline earth metals, silica, and glass bubbles (
An inorganic component such as Sumitomo 3M Co., Ltd. E22×) may also be added. These inorganic components are mainly added as fillers, but especially when calcium carbonate or the like is added, the surface of the adhesive for electroless plating is easily roughened, resulting in improved adhesion. These inorganic components are desirably added in an amount of 25 to 35 parts by weight when the total amount of the thermosetting resin and synthetic rubber is 100 parts by weight, and the particle size thereof is 2.
A thickness of 0 to 30 μm or less, especially several μm or less is suitable.

If necessary, other resins such as epoxy resins may be added.

The adhesive for electroless plating of the present invention includes the above-mentioned rubbers, resins,
It is used as a paste material by dissolving and dispersing metal oxides, inorganic components, etc. in a suitable solvent.

[Example Example 1 Acrylic acid 1 Noronide 1 Nortsukji engineering rubber 50 parts by weight, Novolac type phenol resin 50 parts by weight, Calcium carbonate 3
2 parts by weight, 1 part by weight of zinc white, 0.5 parts by weight of magnesium oxide
! An adhesive having a solid content of 30% was prepared by dissolving and dispersing 1 part of silica and 1511 parts of silica in methyl ethyl ketone and methyl isobutyl ketone. This adhesive was applied to a paper-based phenol laminate (manufactured by Hitachi Chemical Co., Ltd., product name LP-461F) so that the film thickness after drying was 30μ, and dried.
C11 After heat-curing for 20 minutes, holes were drilled at designated locations, and the adhesive surface was roughened by chemical etching, washed with water, neutralized, and washed with water in accordance with the usual method for making printed wiring boards by electroless plating. It was immersed in a plating catalyst solution (manufactured by Hitachi Chemical Co., Ltd., H3IOIB) and then washed with water. Subsequently, a resist was printed and immersed in an electroless steel plating bath to form a conductor circuit approximately 30 scales thick to form a printed wiring board. The peel strength between the plating film and the base material of this printed wiring board is 2.2 kg/c.
m or more, the iron heat resistance was good, and defects such as unevenness, blistering, and copper drop-off were not observed.

Comparative Example 1 An adhesive having the same composition as in Example 1 was prepared except that 2 parts by weight of sulfur was added to 18 ml. A printed wiring board was created using this adhesive in exactly the same manner as in Example 1. The peel strength between the plating film and the base material of this printed wiring board is 1.5 to 9.
/cm or more, iron heat resistance was also good, but unevenness occurred.

[Effects of the Invention] As explained above, when the adhesive for electroless plating of the present invention is used, unevenness does not occur because it does not contain sulfur, and because the resin component has a high degree of crosslinking, peel strength and
It has the effect of improving heat resistance.

Claims (2)

[Claims] (1) An adhesive for electroless plating containing a thermosetting resin, rubber, and metal oxide as constituent components. (2) The adhesive for electroless plating according to claim 1, further containing an inorganic component as a constituent component.