JPH075769B2 - Method for manufacturing epoxy resin laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an epoxy resin laminate having excellent heat resistance, moldability and workability.

[Prior art]

In recent years, in the manufacturing process of a printed circuit board, along with its high accuracy and high density, the printed circuit board is exposed to higher temperatures in the processing step, so that a laminated board having more excellent heat resistance is desired.

Conventionally, in a resin formulation of a heat-resistant epoxy laminate, a bisphenol A type epoxy resin is mixed with a trifunctional or higher-functional epoxy resin (cresol novolac type or phenol novolac type) to obtain a laminate excellent in heat resistance. It was

However, as the compounding amount of the trifunctional or higher epoxy resin is increased, the heat resistance is improved (such as the glass transition temperature is increased), but the rapid gelation peculiar to the trifunctional or higher epoxy resin is accompanied. In addition, deterioration of dimensional stability due to defective molding of the laminated plate and strain during pressurization is observed. Furthermore, due to the increase in cross-linking points, wear of the drill blade during drilling occurs.

Furthermore, blending a large amount of a trifunctional or higher epoxy resin is not desirable because it results in high cost.

[Object of the invention] The present invention was studied for the purpose of improving the formability of a laminated plate and eliminating the problems at the time of drilling without lowering the conventional heat resistance, to complete the present invention. It has come.

[Structure of Invention]

The present invention uses a trifunctional or higher functional epoxy resin having a molecular weight of 300 to 1
A varnish whose main component is an epoxy resin obtained by co-condensing 000 bisphenol A-type epoxy resins and bisphenol A-based compounds is prepared, a base material is impregnated with this varnish, and the obtained prepreg is laminated and heated. A method for producing an epoxy resin laminate, which is characterized by performing pressure molding.

In the present invention, the co-condensed epoxy resin used is 3
An epoxy resin obtained by co-condensing an epoxy resin having a functionality of 10 to 20% is preferable.

Conventionally, in order to obtain a laminate having excellent heat resistance, a bisphenol A type epoxy resin is blended with a bisphenol A type epoxy resin in an amount of 20 to 30% based on the total amount of the two. When a resin is used, even if the proportion of the epoxy resin having a functionality of 3 or more is reduced to 10 to 20%, it is possible to obtain the same heat resistance as the conventional one.

It is considered that this is because the reaction in the case of co-condensation is more uniform than that in the case of blending a conventional epoxy resin having three or more functional groups.

Due to the effect of reducing the epoxy resin having three or more functionalities and the uniform reaction, it is possible to greatly improve the molding failure at the time of molding the laminated plate, and it is possible to mold at a pressure lower than the normally applied pressure. .

This has a great effect on the improvement of dimensional stability by reducing the strain at the time of pressurization, and also improves the plate thickness accuracy of the laminated plate.

Furthermore, the wear of the drill blade during drilling is greatly improved.
It is considered that this is due to the reduction of the epoxy resin having a functionality of 3 or more.

As the trifunctional or higher functional epoxy resin, a phenol novolac type epoxy resin or a cresol novolac type epoxy resin is preferably used.

〔The invention's effect〕

In the epoxy resin laminate obtained according to the present invention, the epoxy resin having a functionality of 3 or more can be reduced without lowering the heat resistance, the moldability is superior to the conventional one, and particularly the low pressure can be applied, and the dimensional stability is improved. Remarkably improved.

Further, the wear of the drill blade during drilling can be greatly reduced, which is suitable as an industrial method for producing an epoxy resin laminate.

〔Example〕

 Examples and comparative examples of the present invention will be shown below.

Example Production of co-condensation type epoxy resin In a container equipped with a stirrer, a thermometer, a nitrogen gas introducing pipe and an external heating source, "Epicoat 828" (Bisphenol A epoxy resin manufactured by Yuka Shell Co .: epoxy equivalent 190) 190
Part, tetrabrom bisphenol A 200 parts, 1% caustic soda solution 0.2 parts, and nitrogen gas purging at 180 ° C
By reacting for 5 hours at the temperature of
A precondensate of 710 was obtained.

Further, 46 parts of this precondensate, 44 parts of "Epicoat 828" and 10 parts of "Epicoat 180S65" (made by Yuka Shell Co., cresol novolac type epoxy resin: epoxy equivalent 220) were used in the same container, and further 1% 0.28 parts of tetramethylammonium chloride aqueous solution was added, and after reacting at 140 ° C. for 4 hours, 92 parts of methyl isobutyl ketone was added,
When dissolved, the bromination rate is 20 with an epoxy equivalent of 470.
% Co-condensed epoxy resin was obtained.

Production of Epoxy Resin Laminated Plate The composition of the epoxy resin-containing varnish is as follows.

A varnish was prepared by dissolving the above blended materials in a solvent of methyl cellosolve and acetone so that the total solid content was 50% by weight.

After the glass cloth was impregnated with this varnish and dried, a prepreg having a resin content of 45% was obtained. Eight sheets of this prepreg were overlaid, and one sheet of 18 μ copper foil was overlaid on each side of the prepreg, and heated and pressed by a press to obtain an epoxy resin laminate having a thickness of 1.6 mm.

Comparative example An epoxy resin laminate was obtained by using the above-mentioned resin-blended epoxy resin in the same manner as in the example.

Table 1 shows the evaluation results of the epoxy resin laminates obtained in Examples and Comparative Examples.

The epoxy resin laminate manufactured according to the present invention is not only excellent in moldability, heat resistance, and drill workability, but also has good general characteristics as a printed circuit board and has excellent practical characteristics. Was confirmed.

Claims (1)

[Claims] 1. A trifunctional or higher functional epoxy resin having a molecular weight of 300.
~ 1000 bisphenol A type epoxy resin and a varnish whose main component is an epoxy resin obtained by co-condensing with a bisphenol A type compound are prepared, the varnish is impregnated into a substrate, and the obtained prepreg is laminated and heated. A method for producing an epoxy resin laminate, which comprises pressure molding.