JP2809714B2 - Adhesive for electroless plating - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an adhesive for electroless plating, for example, suitable for plating on a printed wiring board or a resin by an electroless plating method. The present invention relates to an adhesive for electroless plating.

[Conventional technology]

Generally, a laminate having a surface coated with an adhesive layer having a thickness of 20 to 50 μm made of synthetic rubber and a thermosetting resin is used as a laminate for additive plating or the like.

The surface of the adhesive is chemically or physically roughened, and then subjected to electroless plating, thereby ensuring the adhesion between the electroless plated metal film and the underlying adhesive layer.

However, since the mechanical strength of the fine projections formed by roughening the surface of the adhesive is small, the projections drop off from the surface of the adhesive in a process after the roughening, and as a result, are deposited on the plating resist. Adverse effects such as abnormal plating deposition and a shortened life of the plating solution.

In the adhesive for electroless plating represented by additive plating, in order to prevent the protrusions from falling off,
Various studies have been made on adhesives, but no satisfactory one has been obtained yet.

[Problems to be Solved by the Invention] The present inventors have studied to develop an adhesive for electroless plating that can suppress the roughened protrusion from falling off the adhesive surface, and as a result, completed the present invention. That is what led to it.

[Means for solving the problem]

The present invention relates to an adhesive for electroless plating containing a synthetic rubber and a curable resin as main components, wherein 25 to 50% by weight of an acrylonitrile component (hereinafter, simply referred to as “%”) as a synthetic rubber.
Using NBR, the polyvinyl butyral resin is further added to 50 to 50 parts by weight of the NBR (hereinafter simply referred to as "part").
The present invention relates to an adhesive for electroless plating, wherein 0 parts are blended.

In the present invention, a high acrylonitrile-containing NBR having an acrylonitrile component of 25 to 50% is used as a synthetic rubber component. By using such NBR, the heat resistance of the adhesive is improved and the electrical insulation of the adhesive is excellent. If the acrylonitrile component is less than 25%, NBR has poor heat resistance, and if it exceeds 50%, the electrical insulation of the adhesive tends to be poor.

The curable resin is not particularly limited,
One or more of a thermosetting resin such as an epoxy resin, a resol type phenol resin, or a melamine resin and a photocurable resin such as a polymer of an acrylic ester of a polyhydric alcohol such as trimethylolpropane triacrylate or pentaerythritol acrylate. Two or more can be blended.

These compounding ratios are 100 to 800 parts for an epoxy resin, 20 to 200 parts for a resole phenolic resin, 20 to 100 parts for a melamine resin, and 100 to 800 parts for NBR 100 parts,
50 for trimethylolpropane triacrylate
To 150 parts, and in the case of pentaerythritol triacrylate, 50 to 150 parts are suitable.

The present invention is characterized in that polyvinyl butyral resin is blended in the adhesive in order to suppress the projections after roughening from falling off the adhesive surface.

The polyvinyl butyral resin used in the present invention has a degree of polymerization of 350 or more and a degree of butyralization of 65 mol% or more, such as BL-S, BM-S, BH-S of Sekisui Chemical Co., Ltd.
BX-5, BX-55 and the like can be used.

When the degree of polymerization is less than 350, heat resistance is poor, and when the degree of butyralization is less than 65 mol%, the adhesion between the electroless plating metal film and the base adhesive tends to be poor.

The proportion of the polyvinyl butyral resin in the adhesive is 50 to 500 parts, preferably 100 to 400 parts, per 100 parts of NBR. If the blending amount is less than 50 parts, the effect of suppressing the roughened projections from falling off the adhesive surface cannot be sufficiently increased, and if the blending amount exceeds 500 parts, the base film adheres to the electroless plating metal film. The adhesive strength of the agent is undesirably reduced.

Although the effect of preventing the projections after roughening from dropping off from the adhesive surface is not fully understood, the excellent mechanical strength and tackiness of the polyvinyl butyral resin itself improve the mechanical strength of the adhesive layer and improve the adhesion. It is considered that this contributes to the improvement of the adhesive strength between the resin and the filler.

The adhesive of the present invention may contain an inorganic filler in addition to the aforementioned NBR, curable resin, and polyvinyl butyral resin. As the inorganic filler, silica, calcium carbonate, aluminum hydroxide and the like can be used.

The mixing ratio of these is suitably 30 to 100 parts for silica, 1 to 20 parts for calcium carbonate, and 5 to 40 parts for aluminum hydroxide based on 100 parts of NBR.

Further, if necessary, a vulcanizing agent, a vulcanization accelerator, and an antioxidant can be blended.
The appropriate amount of vulcanizing agent is 0.1 to 10 parts with respect to 00 parts, 0.05 to 5 parts for a vulcanization accelerator, and 0.1 to 10 parts for an antioxidant.

These additives effectively work to improve the heat resistance of the adhesive layer and the adhesion between the electroless plating metal film and the adhesive layer.

〔Example〕

The adhesive for additive plating, which is the adhesive for electroless plating according to the present invention, will be described below with reference to examples and comparative examples.

Example 1 NBR (N-230SH acrylonitrile component 35%, manufactured by Nippon Synthetic Rubber Co., Ltd.) 100 parts Epoxy resin (EP-1007 manufactured by Yuka Shell Co., Ltd.) 150 parts Resole-type phenol resin (PR manufactured by Sumitomo Durez Co., Ltd.) -11078) 70 parts Polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., BH-S polymerization degree: 1000, butyralization degree: 70 mol%) 200 parts Silica (E-220A, manufactured by Nippon Silica Industry Co., Ltd.) 40 parts Adhesive mixture Was applied to an epoxy resin / glass cloth laminate to form an adhesive layer having a thickness of 40 μm.

This adhesive-coated laminate was subjected to 30 μm electroless copper plating by a usual additive method including a roughening step.

Example 2 Except that the amount of polyvinyl butyral resin was reduced to 75 parts, electroless plating was performed in the same manner as in Example 1 to obtain a laminate with electroless copper plating.

Example 3 Except that the amount of polyvinyl butyral resin was increased to 450 parts, electroless plating was performed in the same manner as in Example 1,
A laminate with electroless copper plating was obtained.

Comparative example 1 Except not mix | blending a polyvinyl butyral resin, it carried out similarly to Example 1, and performed electroless plating, and obtained the laminated board with electroless copper plating.

Comparative Example 2 Except that the amount of polyvinyl butyral resin was reduced to 20 parts, electroless plating was performed in the same manner as in Example 1 to obtain a laminate with electroless copper plating.

Comparative Example 3 Except that the amount of polyvinyl butyral resin was increased to 600 parts, electroless plating was performed in the same manner as in Example 1,
A laminate with electroless copper plating was obtained.

Comparative Example 4 A polyvinyl butyral resin was prepared using BL-1 manufactured by Sekisui Chemical Co., Ltd.
(Electroless plating was performed in the same manner as in Example 1 except that the weight was changed to 300 and the butyralization degree was changed to 63 mol%) to obtain a laminate with electroless copper plating.

Comparative Example 5 Polyvinyl butyral resin was used for BL-2 manufactured by Sekisui Chemical Co., Ltd.
(Electroless plating was performed in the same manner as in Example 1 except that the degree of polymerization was changed to 450 and the degree of butyralization was changed to 63 mol%) to obtain a laminate with electroless copper plating.

Evaluation of the detachment of the projections after roughening is performed by pressing a new adhesive surface of cellophane adhesive tape specified in JIS Z 1522 on the roughened adhesive surface by finger pressure so that air bubbles do not remain. The tape was peeled in a direction perpendicular to the tape, and the light transmittance of the tape was measured by setting the light transmittance of the tape before use to 100.

The adhesion between the electroless copper plating film and the adhesive layer is JIS C
Evaluation was based on 6481 (peeling strength).

The solder heat resistance was evaluated based on JIS C 6481.

 Table 1 shows the evaluation results of these characteristics.

As is clear from Table 1, the electroless copper-plated laminates obtained in Examples 1 to 3 have a small number of protrusions after roughening, and the plating peel strength is less than the JIS standard value. 1.4kg
With respect to f / cm, it is 1.7 kgf / cm or more, and the solder heat resistance is 260 ° C for 120 seconds or more compared to the JIS standard value of 260 ° C for 20 seconds, and there is no practical problem.

On the other hand, Comparative Example 1 is not suitable for practical use because the polyvinyl butyral resin is not blended and Comparative Example 2 has a small amount of polyvinyl butyral resin, so that many projections fall off after roughening. In Comparative Example 3, since the amount of polyvinyl butyral resin was large, the peel strength of the plating was small, which was not suitable for practical use.

Comparative Example 4 has a small degree of polymerization of polyvinyl butyral resin and a small degree of butyralization, so that the plating peeling strength is small and solder heat resistance is inferior. Comparative Example 5 has a small degree of butyralization, and The peel strength is low and each is not suitable for practical use.

[Effects of the Invention] As described above, the adhesive for electroless plating of the present invention can effectively prevent the projections after roughening from falling off the adhesive surface. The adhesion of the plated metal is also maintained at a similar level as compared with the case where conventional polyvinyl butyral is not blended.

Continued on the front page (72) Inventor Naohiro Morita 3-11-36 Mita, Minato-ku, Tokyo Inside Sumitomo Bakelite Co., Ltd. (72) Inventor Tetsuro Tomita 3-11-36 Mita, Minato-ku, Tokyo Sumitomo Bakelite shares In-house examiner Yumiko Isshiki (56) References JP-A-49-33987 (JP, A) JP-B-43-17516 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09J 107/00-121/02 C09J 129/14 H05K 3 / 18,3 / 38

Claims (1)

(57) [Claims] 1. An adhesive for electroless plating comprising a synthetic rubber and a curable resin as main components, wherein NBR having an acrylonitrile component of 25 to 50% by weight is used as a synthetic rubber, and the polymerization degree is further increased with respect to 100 parts by weight of the NBR. An adhesive for electroless plating, comprising 50 to 500 parts by weight of a polyvinyl butyral resin having a butyralization degree of at least 350 and a mole ratio of at least 65 mol%.