JP2674434B2 - Laminated board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate suitable as a substrate for a printed circuit board having an ultraviolet ray transmission preventing function.

[0002]

2. Description of the Related Art In a printed circuit board, a metal foil of a double-sided metal foil-clad laminate is etched by a photoresist method to form a circuit, and a solder resist is provided on a predetermined portion by the photoresist method. An ultraviolet curable resin such as an acrylic modified epoxy resin is used as the solder resist. A layer of an ultraviolet curable resin is formed on the entire surface of the circuit, and ultraviolet rays are irradiated only to a portion where a solder resist is to be formed to cure the resin to function as a solder resist. The uncured resin is washed off and removed. In order to simultaneously irradiate the ultraviolet curable resin layers of the circuits on both sides with ultraviolet rays so that the solder resist can be formed, the laminated board, which is the circuit board, must have an ultraviolet shielding property. This is because, if the ultraviolet light emitted from one surface is transmitted to the opposite surface, the portion on the opposite surface where the solder resist is not desired to be formed is exposed and the resin in that portion is cured. A laminated plate is made by impregnating a sheet-like base material made of glass fiber with a resin, and stacking multiple sheets to heat and press-mold them. There have been proposed techniques for blending agents and optical brighteners, and techniques for pretreating sheet-shaped substrates with ultraviolet absorbers and optical brighteners.

[0003]

The laminated plate according to the above-mentioned prior art has a good ultraviolet ray shielding property, but it causes a problem that the laminated plate is discolored by heating and the chemical resistance is lowered (elution of the fluorescent whitening agent). was there. The problem to be solved by the present invention is
It is an object of the present invention to provide a laminate having an ultraviolet ray shielding property suitable as a substrate for a printed circuit and free from heat discoloration and deterioration in chemical resistance (elution of a fluorescent whitening agent).

[0004]

In order to solve the above-mentioned problems, in a laminated board according to the present invention, a sheet-like base material made of glass fibers is impregnated with a resin, and a plurality of the sheets are superposed and integrated. The glass fiber is characterized in that the alkali component (Na ₂ O and K ₂ O) contained in the glass fiber is 20 to 50% by weight, and the impregnating resin amount is 40% by weight or more. The impregnating resin amount is preferably 45% by weight or more.

[0005]

The laminated plate according to the present invention is one in which the defects of alkali glass for electrical insulation are suppressed and only the property of shielding ultraviolet rays is obtained. The sheet-like base material for impregnating the resin is made of glass fibers such as E glass and S glass, but the laminated board for a printed circuit is required to have high electric insulation properties, and therefore E containing a small amount of alkali Glass (about 0.6% by weight of alkali component) is used. However, the present inventors have found that, in a laminated plate for electrical insulation, if a sheet-shaped substrate is made of glass fiber whose alkali component is increased, a good ultraviolet shielding property can be obtained. If the content of the alkali component contained in the glass fiber is less than 20% by weight, the ultraviolet ray shielding effect is weak and 5
If the content exceeds 0% by weight, the electrical insulation properties of the laminate will deteriorate, so the content of the alkali component is limited to the above range. The electrical insulation characteristics of the laminated plate are maintained to such an extent that no practical problems will occur if the amount of resin impregnated into the sheet-shaped substrate is 40% by weight or more. By setting the resin impregnation amount to be in the range of 45% by weight or more, the electric insulation property is further improved.
Even if it is said that the resin impregnation amount is increased to improve the electric insulation property, when glass woven fabric is used, the limit is about 55% by weight in terms of manufacturing. It is impossible to impregnate a large amount of resin indiscriminately.

[0006]

【Example】

Examples 1 to 6 and Comparative Examples 1 to 3 A glass woven fabric was formed of glass fibers obtained by melt spinning glass with various alkali component contents as shown in Table 1 and Table 2. 100 parts by weight of brominated bisphenol A type epoxy resin (Epicoat EP-1046, manufactured by Yuka Shell Co., Ltd.),
4 parts by weight of dicyandiamide and 0.15 parts by weight of 2-ethyl-4-methylimidazole were mixed and dissolved in methyl ethyl ketone and methyl glycol to prepare a varnish having a solid content of 60% by weight. This varnish was impregnated into the above various glass woven fabrics and dried to obtain a prepreg having a resin amount of 42% by weight. Two pieces of this prepreg are piled up, and 18 μm copper foil is also placed on both sides.
The sheets were stacked one by one and heat-pressed at a temperature of 170 ° C. and a pressure of 60 kg / cm ² for 90 minutes to obtain a double-sided copper-clad laminate having a thickness of 0.4 mm.

Conventional Example 1 The varnish of the above-mentioned Example 1 was added to the optical brightener (Kayalight).
(B, manufactured by Nippon Kayaku Co., Ltd.) 0.5 part by weight was added to prepare a varnish. A glass woven cloth of E glass was impregnated with this varnish and dried, and then a double-sided copper-clad laminate was obtained in the same manner as in Example 1.

Conventional Example 2 The varnish used in the above-mentioned Example 1 contains 2-
A varnish was prepared by adding 5 parts by weight of (2'-hydroxy-5'-methylphenyl) benzotriazole. A glass woven cloth of E glass was impregnated with this varnish and dried, and then a double-sided copper-clad laminate was obtained in the same manner as in Example 1.

The characteristics of the copper clad laminates of Examples, Comparative Examples and Conventional Example are shown in Tables 1 to 3.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

The test methods and evaluation criteria for the properties shown in Tables 1 to 3 are as follows. Opposite side exposure property evaluation criteria ○: No exposure, △: Small exposure,
×: Large exposure Insulation resistance: Saturated water vapor pressure 121 ° C-measured after treatment at 2 atm for 24 hours Chemical resistance: Treatment with trichlene boiling for 30 minutes Chemical resistance evaluation criteria ○: No abnormality, ×: Rough skin or elution Heat discoloration: 170 ° C -Observation after 1 hour treatment Heat discoloration ○: No discoloration ×: Discoloration

[0014]

The laminated board according to the present invention retains sufficient insulating properties and ultraviolet shielding performance as an insulating substrate for a printed circuit, and since it does not use an ultraviolet absorber or a fluorescent whitening agent, It is possible to prevent deterioration of chemical resistance and discoloration due to heating caused by.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H05K 1/03 610 B29C 67/14 X // B29K 105: 08 B29L 31:34

Claims (2)

(57) [Claims] 1. A laminated plate in which a sheet-shaped base material made of glass fibers is impregnated with a resin and a plurality of the sheets are superposed and integrated with each other, wherein alkali components (Na ₂ O and K ₂ O) contained in the glass fibers are contained. ) Is 20 to 50% by weight, and the amount of impregnated resin is 40% by weight or more. 2. The laminated board according to claim 1, wherein the amount of impregnated resin is 45% by weight or more.