JPH06112611A - Laminated board for printed circuit - Google Patents

Abstract

PURPOSE:To acquire a laminated board for a printed circuit having tracking resistance by using a thermosetting impregnated glass fabric wherein inorganic filler is contained by a specified wt.% to resin of a surface layer. CONSTITUTION:An inorganic filler whereto gibbsite type ammonium hydroxide of 50 parts and superfine powder silica of 2 parts to 100 parts of resin are mixed is added to epoxy resin varnish, agitated and mixed to prepare inorganic filler containing varnish. The inorganic filler-containing varnish is infiltrated and dried in glass fabric to make its resin content 30 to 40%, and a glass fabric prepreg A is acquired. Then, epoxy resin varnish is infiltrated and dried in glass fabric to make its resin content 40 to 50%, and a glass fabric prepreg B is acquired. Thereafter, 6 sheets of the epoxy resin glass fabric prepreg B are laminated, one sheet of the inorganic filler-containing epoxy resin glass fabric prepreg A is laminated on each of both sides thereof, and one sheet of copper foil is further laminated on each of both sides thereof for lamination molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit laminate used in electric equipment, electronic equipment, communication equipment and the like.

[0002]

2. Description of the Related Art As consumer electronic devices and industrial electronic devices are becoming smaller and more sophisticated, heavy loads such as transformers and transistors are used in power supply boards to which high voltage is applied, such as computers and measuring instruments. Since it is mounted, a thermosetting resin glass woven fabric laminated plate has been used from the viewpoint of strength. Furthermore,
In addition to this, tracking resistance has been required from the standpoint of ensuring safety for higher density.
Conventionally, in a phenolic resin laminate used for consumer equipment, due to this tracking resistance, an adhesive used for adhering a metal foil to the laminate is made of a melamine resin, an alicyclic epoxy resin or a polyester resin which is hard to be carbonized. Has been used. However, as epoxy laminates such as composite laminates tend to become thinner as the size and density increase, the metal foil tends to become thinner, making it difficult to apply adhesive to the metal foil, or curling after application. Due to this, the metal foil with adhesive cannot be used. On the other hand, for industrial equipment, alicyclic epoxy resins and unsaturated polyester resin-based resins with few aromatic rings have been used to improve tracking resistance, but high cost, heat resistance, metal There were problems such as weak peeling strength from the foil.

[0003]

The present invention has been made as a result of various studies in order to solve the above problems.
The purpose thereof is to provide a laminate for a printed circuit, which has tracking resistance without deteriorating electrical characteristics and other characteristics.

[0004]

The present invention is characterized in that the surface layer is made of a thermosetting resin glass woven fabric containing an inorganic filler in an amount of 10 to 200% by weight based on the resin of the surface layer. It is a laminated board for a printed circuit. The inorganic filler used in the present invention is contained in the surface layer resin in an amount of 10 to 200% by weight, preferably 20 to 150% by weight. If it is 10% by weight or less, the effect of tracking resistance is small, and if it is 200% by weight or more, the resin viscosity becomes too high when the inorganic filler is mixed, and it becomes difficult to impregnate the glass woven fabric substrate. The epoxy resin varnish may be mixed with the inorganic filler only in the surface layer or in a layer other than the surface layer.

As the inorganic filler, there are aluminum hydroxide, silica, talc, wollastonite, magnesium hydroxide, clay and the like, but aluminum hydroxide is preferable in view of flame retardancy, processability and heat resistance. . Furthermore, when aluminum hydroxide is used for the surface layer, the effect of improving tracking resistance is great. The thermosetting resin used in the present invention is preferably an epoxy resin, but other than this, a polyimide resin, an unsaturated polyester resin, a phenol resin or the like can be used. According to the present invention, while improving the tracking resistance, while maintaining the solder heat resistance and the copper foil peeling strength, it is possible to improve the surface roughness by entering the inorganic filler between the filaments of the glass woven fabric. it can.

[0006]

[Function] The reason why the inorganic filler compounded in the thermosetting resin of the surface layer improves the tracking resistance is that the inorganic filler is present on the surface of the molded laminate, whereby the proportion of the resin on the surface is improved. It is thought to be due to the decrease. Aluminum hydroxide (hydrated alumina) is preferred as the inorganic filler because the heat of discharge decomposes the aluminum hydroxide to generate water, and the water and the organic matter decomposed by the discharge react to make it volatile. It is considered that the formation of the track is prevented by the generation of the substance.

[0007]

EXAMPLES Examples of the present invention and comparative examples (conventional examples) are described below.
Indicates. "Part" means "part by weight" and "%" means "% by weight". << Example 1 >> The composition of the varnish containing the epoxy resin is as follows. (1) Brominated epoxy resin (Ep-1046 manufactured by Yuka Shell Co., Ltd.) 100 parts (2) Dicyandiamide 4 (3) 2 Ethyl 4-methylimidazole 0.15 (4) Methylcellosolve 36 (5) Acetone 60 Mix the above materials To produce a uniform varnish. Subsequently, an inorganic filler having the following composition was added to 100 parts of the resin content of the epoxy resin varnish, and the mixture was stirred and mixed to prepare an inorganic filler-containing varnish. (1) Gibbsite type aluminum hydroxide 50 parts (Showa Denko's Heidilite H-42) (2) Ultrafine powder silica (Shionogi Pharmaceutical Carplex) 2

A glass woven fabric (WE-18KRB-84 manufactured by Nitto Boseki) containing this inorganic filler-containing varnish having a resin content of 30 to 40%
Was impregnated and dried to obtain a glass woven fabric prepreg (A). Subsequently, the epoxy resin varnish was added to a glass woven fabric (WE-18KRB-84 manufactured by Nitto Boseki) with a resin content of 40 to 50%.
Impregnated and dried to become glass woven prepreg (B)
Got Next, six pieces of the epoxy resin glass woven cloth prepreg (B) are stacked, and one sheet of the inorganic filler-containing epoxy resin glass woven cloth prepreg (A) is stacked on both sides thereof.
Furthermore, layer 18 μm thick copper foil on each side,
Laminating was performed for 90 minutes at a molding temperature of 165 ° C. and a pressure of 60 kg / cm ² to obtain a copper-clad laminate having a thickness of 1.6 mm.

Example 2 Eight sheets of only the inorganic filler-containing epoxy resin glass woven prepreg (A) of Example 1 were overlaid, and copper foil of 18 μm in thickness was overlaid on both sides thereof, and the following Example 1 was used. A copper clad laminate was obtained in the same manner as in. <Example 3> In the same manner as in Example 1, except that the content of gibbsite type aluminum hydroxide was changed from 50 parts to 100 parts in the inorganic filler-containing epoxy resin glass woven prepreg (A) of Example 1. A copper clad laminate was obtained. << Comparative Example >> Eight sheets of the epoxy resin glass woven prepreg (B) of Example 1 alone were overlaid, and a copper foil having a thickness of 18 μm was overlaid on both sides thereof, respectively. Got

In the above examples and comparative examples, tracking resistance, solder heat resistance, and copper foil peeling strength were measured. The results are shown in Table 1. The dimensional stability, the reliability of through-hole plating, the electrical insulation, etc. were also measured, but no difference was observed between the example and the comparative example.

[0011]

[Table 1]

[0012]

The printed circuit laminate of the present invention is particularly suitable for industrial printed circuit boards because it has particularly excellent tracking resistance, heat resistance, copper foil peeling strength and surface smoothness. .

Claims (1)

[Claims] 1. A laminated board for a printed circuit, wherein the surface layer is made of a thermosetting resin-impregnated glass woven cloth containing 10 to 200% by weight of an inorganic filler with respect to the resin of the surface layer.