JPH0715020B2 - Paper-based phenol resin prepreg manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a paper-based phenolic resin prepreg used for a paper-based phenolic resin laminated plate or the like.

[Conventional technology]

In recent years, there is a strong need for higher density of printed wiring boards for consumer equipment, and the paper-based phenolic resin copper-clad laminates used are required to have high electrical insulation.

A paper base phenol resin prepreg is used for the insulating layer of the paper base phenol resin copper clad laminate. This prepreg is made by impregnating a paper base material with a resin varnish.

[Problems to be Solved by the Invention]

If it is attempted to improve the electrical insulation of the prepreg by the conventional method for producing a paper-based phenolic resin prepreg, the punching property is deteriorated.

Therefore, the present invention aims to provide a method for producing a paper-based phenol resin prepreg capable of obtaining a paper-based phenol resin laminate having improved electrical insulation without deteriorating punching properties. And

[Means for Solving the Problems] In order to solve the above problems, the present invention relates to a paper substrate phenol in which a paper substrate is impregnated with a hydrophilic varnish and dried, and then impregnated with a hydrophobic resole varnish and dried. In the method for producing a resin prepreg, a hydrophilic varnish plasticized with an alkylphenol is used as the hydrophilic varnish,
The method for producing a paper-based phenol resin prepreg is characterized in that the impregnated amount of the hydrophilic varnish is 25 to 35% by weight.

Here, the impregnation amount of the hydrophilic varnish is Required by.

As the paper base material, the hydrophilic varnish (hydrophilic resin varnish) and the hydrophobic resole varnish used in the present invention, those used in the production of ordinary paper base phenol resin prepregs can be used. For example, a hydrophilic varnish is a water-based (hydrophilic, mostly monomer) varnish such as melamine resin and phenol resin, which is an addition polycondensation varnish with an aldehyde such as formaldehyde in the presence of an alkaline catalyst such as caustic soda and amine. The solvent is water or a mixed solvent of water and methanol or the like. However, in the present invention, the hydrophilic varnish obtained by plasticizing the hydrophilic varnish with an alkylphenol is used because the punching property is further improved. The hydrophobic resole varnish is, for example, a reaction product obtained by reacting a phenol and an aldehyde with a small amount of free monomers, which is insoluble in water and soluble in alcohol, etc., dissolved in alcohol, etc.

The paper substrate is impregnated with the hydrophilic varnish, for example in the usual way, and dried. In this invention, the hydrophilic varnish is impregnated so that the impregnated amount of the hydrophilic varnish is 25% by weight or more and 35% by weight or less. The hydrophobic resole varnish is then impregnated, for example in the usual way, and dried. In this way, a paper-based phenol resin prepreg (resin paper) is obtained.

A desired number of the obtained paper base phenolic resin prepregs are stacked, and if necessary, a metal foil such as a copper foil is stacked on one or both surfaces of the stacked product, and further, if necessary, a prepreg and a metal foil A paper-based phenolic resin laminate is obtained by interposing an adhesive between them and performing heat-pressing (press) molding. The laminated board using the prepreg obtained by the method of the present invention can realize the improvement of electrical insulation without deteriorating the punching property.

[Action]

If the amount of impregnation of the hydrophilic varnish plasticized with alkylphenol into the paper substrate is less than 25% by weight, the electrical insulation cannot be improved, and if it exceeds 35% by weight, the punching property deteriorates.

〔Example〕

Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples.

Preparation Example 1 of hydrophilic varnish 100 parts by weight of phenol (hereinafter, "parts by weight" will be referred to as "parts"), 70 parts of butylphenol, 170 parts of formalin (50%)
And 3 parts of trimethylamine were reacted at 80 ° C. for 2 hours, 100 parts of melamine and 80 parts of formalin (50%) were added, and the mixture was further reacted at 80 ° C. for 1 hour. The obtained cocondensate was diluted with water and methanol to obtain a varnish having a solid content concentration of 15%. To 100 parts of this varnish, 5 parts of antimony pentoxide sol having a solid content of 50% was added and uniformly dispersed.

Preparation Example 2 of hydrophilic varnish 100 parts of phenol, 70 parts of nonylphenol, 90 parts of formalin (50%) and 2 parts of triethylamine were reacted at 80 ° C for 1 hour (A).

On the other hand, 100 parts of melamine, 100 parts of formalin (37%) and 2 parts of triethylamine were reacted at 80 ° C. for 30 minutes (B).

50 parts of the reaction product of (A) above and 50 parts of the reaction product of (B) above were mixed and further reacted at 80 ° C. for 1 hour, and the obtained cocondensate was diluted with water and methanol to obtain 15% solids. A varnish with a partial concentration was obtained.

-Example 1-Kraft paper was passed through once and impregnated with a melamine resin varnish plasticized with an alkylphenol resin (hydrophilic varnish obtained in Preparation Example 1 above) and dried to obtain a resin component (impregnation amount). A base material containing 25% by weight was obtained.

Next, the obtained substrate was passed through twice, phenol,
Impregnated with resole varnish consisting mainly of formalin and paulownia oil, dried and 50% resin content (including the one-time pass)
To obtain a paper-based phenol resin prepreg (resin paper).

Eight pieces of the obtained resin paper and a copper foil with an adhesive were laminated and heat-pressed to obtain a copper-clad laminate.

The single pass means the first immersion in the varnish of the paper substrate, and the second pass means the immersion in the varnish of the paper substrate subjected to the first immersion, that is, the second immersion. Means immersion.

-Example 2-A resin paper was obtained in the same manner as in Example 1 except that the resin content of the base material obtained by single-passing was 35%, and a copper clad laminate was obtained.

-Comparative Example 1-In Example 1, resin paper was obtained in the same manner as in Example 1 except that the resin content of the substrate obtained by single pass was changed to 15% to obtain a copper clad laminate.

-Comparative Example 2-A resin paper was obtained in the same manner as in Example 1 except that the resin content of the base material obtained by one pass was 40%, and a copper clad laminate was obtained.

-Comparative Example 3-In Example 1, the melamine resin was used in one pass, and the resin content of the base material obtained in one pass was
A resin paper was obtained in the same manner as in Example 1 except that the content was 15% to obtain a copper clad laminate.

-Comparative Example 4- In Comparative Example 3, a resin paper was obtained in the same manner as in Comparative Example 3 except that the resin content of the base material obtained by one pass was changed to 30% to obtain a copper clad laminate.

The properties of the obtained copper clad laminate are shown in Table 1. The punching property is 1.78 pitch part (pin diameter 0.9m
m) x 13 x 6 locations = 156 in total were confirmed, and the rate of occurrence of surface cracks in 156 was evaluated. When surface cracks occur, the electrical insulation deteriorates.

○… 0 to 10 △… 10 to 50 × ×… 50 or more In the example, both insulation resistance and punching property are good, but in the comparative example, either one of them is bad.

In addition, in Examples 1 and 2, similar results were obtained even when the varnish of Preparation Example 2 was used instead of the varnish of Preparation Example 1.

〔The invention's effect〕

As described above, when the prepreg obtained by the method for producing a paper-based phenolic resin prepreg according to the present invention is used, the paper-based phenolic resin laminate having improved electrical insulation without deteriorating the punching property. The board can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Ezaki 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP 59-45315 (JP, A) JP 55-135661 ( JP, A)

Claims (1)

[Claims] 1. A method for producing a paper-based phenol resin prepreg in which a paper base material is impregnated with a hydrophilic varnish and dried, and then impregnated with a hydrophobic resole varnish and dried, wherein the hydrophilic varnish is plasticized with alkylphenol. Using the hydrophilic varnish prepared above,
A method for producing a paper-based phenolic resin prepreg, which comprises 25 to 35% by weight.