JP2740600B2 - Printed circuit laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As consumer electronic equipment and industrial electronic equipment are becoming smaller and more sophisticated, a power supply board to which a high voltage is applied, such as a computer or a measuring instrument, has a heavy load such as a transformer or a transistor. , Thermosetting resin glass woven fabric laminates have been used from the viewpoint of strength. Furthermore,
In addition, tracking resistance has come to be required from the standpoint of ensuring security in order to increase the density.
Conventionally, in phenolic resin laminates used for consumer equipment, melamine resin, alicyclic epoxy resin, or polyester resin, which hardly carbonizes, is used for the adhesive used to adhere the metal foil to the laminate due to the tracking resistance. Has been used. However, epoxy laminates such as composite laminates tend to be thinner as the size and density increase, so it is difficult to apply an adhesive to the metal foil, or it may curl after coating. This makes it impossible to use the metal foil with adhesive. On the other hand, in the case of industrial equipment, alicyclic epoxy resins and resins with few aromatic rings such as unsaturated polyester resins have been used to improve tracking resistance. There were problems such as weak peeling strength with foil.

[0003]

SUMMARY OF THE INVENTION The present invention has been made as a result of various studies to solve the above problems.
An object of the present invention is to provide a printed circuit board having tracking resistance without deteriorating electric characteristics and other characteristics.

[0004]

According to the present invention, 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 an amount of 10 to 200% by weight, preferably 20 to 150% by weight, based on the resin of the surface layer. When the content is 10% by weight or less, the effect of tracking resistance is small, and when the content is 200% by weight or more, the resin viscosity at the time of mixing the inorganic filler becomes too high, and it becomes difficult to impregnate the glass woven fabric substrate. The inorganic filler may be added to the epoxy resin varnish only in the surface layer, or may be added to a layer other than the surface layer.

The inorganic filler includes aluminum hydroxide, silica, talc, wollastonite, magnesium hydroxide, clay and the like. Aluminum hydroxide is preferred from the viewpoint of flame retardancy, workability and heat resistance. . Further, when aluminum hydroxide is used for the surface layer, the effect of improving the 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 tracking resistance, while maintaining solder heat resistance and copper foil peel strength, it is possible to improve the surface roughness by inserting an 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 formed laminated board, thereby reducing the proportion of the resin on the surface. It is thought to decrease. Aluminum hydroxide (alumina hydrate) is preferred as the inorganic filler because aluminum hydroxide is decomposed by the heat of discharge to generate water, and water reacts with the organic matter decomposed by the discharge to become volatile. It is considered that the formation of the material prevents formation of tracks.

[0007]

Examples of the present invention and comparative examples (conventional examples) are described below.
Is shown. “Parts” indicates “parts by weight” and “%” indicates “% by weight”. Example 1 The composition of a varnish containing an epoxy resin is as follows. (1) 100 parts of brominated epoxy resin (Ep-1046 manufactured by Yuka Shell) (2) dicyandiamide 4 (3) 2-ethyl 4-methylimidazole 0.15 (4) methyl cellosolve 36 (5) acetone 60 To produce a uniform varnish. Subsequently, an inorganic filler having the following composition was added to the epoxy resin varnish based on 100 parts of the resin component, and the mixture was stirred and mixed to prepare an inorganic filler-containing varnish. (1) Gibbsite type aluminum hydroxide 50 parts (Heidilite H-42 manufactured by Showa Denko) (2) Ultra fine powder silica (Carplex manufactured by Shionogi Pharmaceutical Co., Ltd.) 2

This varnish containing an inorganic filler is coated on a glass woven fabric (WE-18KRB-84 manufactured by Nitto Boss) with a resin content of 30 to 40%.
To obtain a glass woven prepreg (A). Subsequently, the epoxy resin varnish was applied to a glass woven fabric (WE-18KRB-84, manufactured by Nitto Boss) so that the resin content was 40 to 50%.
Impregnated and dried to become a glass woven prepreg (B)
I got Next, six sheets of the epoxy resin glass woven prepreg (B) are stacked, and one sheet of the inorganic filler-containing epoxy resin glass woven prepreg (A) is stacked on both sides thereof,
Furthermore, copper foil with a thickness of 18 μm is layered on each side,
Lamination molding was performed at a molding temperature of 165 ° C. and a pressure of 60 kg / cm ² for 90 minutes to obtain a copper-clad laminate having a thickness of 1.6 mm.

<< Embodiment 2 >> Only the inorganic filler-containing epoxy resin glass woven prepreg (A) of Embodiment 1 was stacked on eight sheets, and copper foil of 18 μm thickness was stacked on both sides thereof one by one. In the same manner as in the above, a copper-clad laminate was obtained. << Example 3 >> In the same manner as in Example 1 except that the amount of the gibbsite type aluminum hydroxide was changed from 50 parts to 100 parts in the prepreg (A) of the epoxy resin glass woven fabric containing the inorganic filler of Example 1. A copper-clad laminate was obtained. << Comparative Example >> Eight epoxy resin glass woven fabric prepregs (B) of Example 1 alone were stacked, and copper foils having a thickness of 18 μm were stacked on both surfaces thereof one by one. I got

In the above Examples and Comparative Examples, tracking resistance, solder heat resistance, and copper foil peeling strength were measured. Table 1 shows the results. In addition, dimensional stability, through-hole plating reliability, electrical insulation, and the like were also measured, but no difference was observed between the example and the comparative example.

[0011]

[Table 1]

[0012]

The printed circuit board 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)

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