JPS6155124A - Production of laminated sheet - Google Patents

Abstract

PURPOSE:To obtain a laminated sheet of great industrial value as an electrical insulation material, by controlling migration of silver by providing one prepreg on the uppermost paper base. CONSTITUTION:An intermediate layer is formed by laminating a suitable number of prepregs each of which is obtained by infiltrating an oil-modified phenolic resin into a paper base precoated with a water-soluble phenolic resin and drying it. One prepreg obtained by precoating a paper base with a water-soluble phenolic resin, infiltrating an epoxy resin into this base and drying it is provided as a surface layer onto the intermediate layer to obtain the desired laminated sheet. Any of bisphenol, epoxy, novolak and like epoxy resins can be used as the epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a phenolic resin laminate that is effective in preventing silver migration.

BACKGROUND OF THE INVENTION In recent years, with the development of the electrical and electronic equipment industries, laminates with advanced electrical properties have been developed.

Particularly in the field of benign electronic devices, it is essential to reduce the cost of printed wiring boards using phenolic resin laminates and to increase wiring density. In manufacturing printed wiring boards, high-density wiring is achieved by printing a conductive paint containing silver as a main component on a phenolic resin laminate to form an electrically conductive circuit. Currently, the spacing between conductive circuits printed with silver on printed wiring boards is becoming less than 2.5 m pitch.

Problems to be Solved by the Invention Conventional phenolic resin laminates are made by laminating and molding prepregs obtained by pre-treating a paper base material with a water-soluble phenolic resin, impregnating it with an oil-modified phenolic resin and drying it. However, as mentioned above, the conductive circuit interval due to silver printing is 2.5 m.
When the width becomes narrower than the pitch, silver migration cannot be completely prevented.

An object of the present invention is to suppress silver migration in a paper-based phenolic resin laminate.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention, as a result of intensive studies, has developed a paper base material which has been pretreated with a water-soluble phenol resin and dried, and then impregnated with an oil-modified phenol resin and dried. It is characterized by stacking a number of sheets to form an intermediate layer, and after pre-treating and drying a paper base material with a water-soluble phenol resin, a single sheet of prepreg impregnated and dried with an epoxy resin is laminated and molded as a surface layer. Bisphenol-type epoxy, novolac-type epoxy, etc. can be used as the epoxy resin. Paper base materials originally have a negative effect on preventing silver migration. By comprising, silver migration can be effectively suppressed.

Example Next, the present invention will be explained in detail.

Example 1 The following water-soluble phenolic resin was used. first,
Phenol 9401, paraformaldehyde 900? The initial condensate of maldehyde was diluted with a mixed solvent of water and methanol under a trimethylamine catalyst so that the resin solids amounted to 15% by weight.

On the other hand, oil-modified phenolic resin is metacresol 500
f, tung oil 60 (l) under para-toluenesulfonic acid catalyst
React at 0°C for 1 hour, then add phenol 450F, rose formaldehyde 3852.25% ammonia water 27%
．． 5F was added, reacted at 80°C for 4 hours, dehydrated, and then diluted with a solvent so that the resin solid content was 50% by weight.

The epoxy resin is epoxy resin (product name ESA-001
, made by Custom Chemical Co., Ltd.), 20 parts by weight of novolac type phenol resin (trade name TD-2093, made by Dainippon Ink) as a curing agent, and 0 parts of benzyldimethylamine as a curing accelerator.
．． A fest containing 3 parts by weight is used.

First, 11 mils kraft paper was impregnated with 15% of the water-soluble phenolic resin and dried, and then impregnated with the tung oil-modified phenolic resin and dried to obtain a prepreg with a resin content of 48% (
Prepreg (A)). Next, water-soluble phenolic resin 2 on 11 mils kraft paper! -15% impregnated and dried, and further impregnated and dried with the above epoxy resin to obtain a prepreg with a resin content of 48% (referred to as prepreg (B)).

Six sheets of the above prepreg (A) are used as an intermediate layer, and the prepreg (
B) One sheet was used as both surface layers and heat-formed at 1f:100 under a pressure of 9/m at 160 tl for 30 minutes to obtain a laminate with a thickness of 1.6 m (referred to as invention product 1).

Example 2 A combination of prepregs (A) and (B) similar to those in Example 1 was further placed with copper foil on one side, and heat-formed at 160°C for 30 minutes under a pressure of 100 Kp/, -yl, and L6■ A thick copper-clad laminate was obtained (referred to as invention product 2).

Conventional Example 8 sheets of prepreg (A) similar to Example 1 were stacked and 100
K9/cdO) under pressure at 160° C. for 30 minutes to obtain a laminate with a thickness of 1.6 (referred to as a conventional product).

In Table 1, the presence or absence of silver migration was investigated using a test piece in which a test pattern 2 was printed on a laminate 1 with a conductive paint containing silver as a main component, as shown in FIG. 40℃
- Test pattern 2 in an atmosphere of 95% RH! DC50v between poles? : was applied, and the appearance after treatment for 1000 hours was observed with a microscope (30 to 100 magnification) and determined.

Moreover, the fertility resistance was measured based on the JIS standard after 2 hours of boiling.

Effects of the Invention As is clear from the results in Table 1, by molding a single layer of epoxy resin prepreg on the outermost surface, a remarkable effect of preventing silver migration can be seen. is a dog.

[Brief explanation of drawings]

FIG. 1 is a plan view of a silver migration test piece.

Claims (1)

[Claims] A prepreg obtained by impregnating and drying an oil-modified phenol resin on a paper base material pretreated with a water-soluble phenolic resin was used as the intermediate layer, and a prepreg obtained by impregnating and drying an epoxy resin on a paper base material pretreated with a water-soluble phenolic resin was used as the intermediate layer. A method for manufacturing a laminate, characterized by laminating and molding one sheet of prepreg as a surface layer.