Laminated board and process for production thereof

A roll of a long substrate (a woven glass fiber fabric, WE-18K RB-84, product of Nitto Boseki Co., Ltd.) was unwinded. On the upper side of the unwinded woven glass fiber fabric was coated an epoxy resin varnish P having the following formulation, by use of a knife coater so as to give a film thickness (as dried) of about 50 .mu.m.

Then, drying was conducted at 120.degree. C. for 1 minute. Subsequently, a varnish A1 having the following formulation was coated on the varnish P-coated side of the substrate by use of a knife coater so as to give a film thickness (before drying) of 0.9 mm.

Next, on the varnish A1-coated side of the substrate was laminated a nonwoven glass fiber fabric (EP-4075, product of Japan Vilene Co., Ltd.) having a unit area weight of 75 g / m.sup.2. On the back side of the substrate was coated a varnish B1 having the following formulation, by use of a roll coater.

The resulting material was dried at 140.degree. C. for 3 minutes by use of a dryer to obtain a prepreg com

A roll of a long substrate (a woven glass fiber cloth, WE-18K RB-84, product of Nitto Boseki Co., Ltd.) was unwinded. On the upper side of the substrate was coated the varnish P, followed by drying, in the same manner as in Example 1. On the varnish P-coated side of the substrate was coated a varnish A2 having the following formulation, by use of a knife coater so as to give a film thickness (before drying) of 0.9 mm.

The resulting material was dried at 150.degree. C. for 1 minute by use of a dryer. The subsequent procedures were carried out as mentioned in Example 1 to prepare a copper-clad laminated board having a thickness of 1.6 mm.

An epoxy resin varnish B3 having the following formulation was prepared.

The above varnish B3 was impregnated into a long substrate (a woven glass fiber fabric, WE-18K RB-84, product of Nitto Boseki Co., Ltd.) so that the resin content in the impregnated substrate became about 40% by weight, followed by drying at 140.degree. C. for 2 minutes, to obtain a woven glass fiber fabric prepreg [A].

Separately, the following inorganic fillers of the following amounts were added to the above-mentioned varnish B3 containing 100 parts by weight of the brominated epoxy resin, followed by stirring, to prepare a varnish A3 containing the brominated epoxy resin and inorganic fillers.

The varnish A3 was coated on one side of the woven glass fiber fabric prepreg [A] by use of a knife coater so as to give a film thickness (as dried) of 0.6 mm. Thereon was laminated a nonwoven glass fiber fabric (EP-4075, product of Japan Vilene Co., Ltd.) having a unit area weight of 75 g / m.sup.2, followed by drying at 1