【発明の詳細な説明】[Detailed description of the invention]
産業上の利用分野
本発明は、電気電子機器などの電気絶縁材とし
て使用される印刷回路用絶縁板の製造法に関す
る。
従来の技術
印刷回路用絶縁板は、紙あるいは各種繊維の
布、マツト等のシート状基材にフエノール樹脂、
メラミン樹脂、ポリエステル樹脂、エポキシ樹
脂、シリコン樹脂等の熱硬化性樹脂を含浸乾燥し
て得たプリプレグを複数枚積み重ね、これを加熱
加圧成形して製造している。
発明が解決しようとする問題点
しかし、上記シート状基材は、パルプやガラス
繊維等を紙、ガラス布等に加工したものであり、
その製造工数が多くかかり、コスト高となる欠点
がある。これを改善するために、パルプ、ガラス
繊維等の充填材と樹脂を混合混練してなる粒状乃
至粉状の成形材料を射出成形や圧縮成形して板状
の成形品を得、これを印刷回路用絶縁板として使
用することも提案されているが、板層が薄い場
合、曲げ強さ等の強度が十分でなくまだ広く実用
化されていない。
本発明は、低コストで機械的強度を十分に保持
した印刷回路用絶縁板を提供することを目的とす
る。
問題点を解決するための手段
上記目的を達成するために、本考案は、シート
状基材に樹脂を含浸乾燥したプリプレグと、充填
材と樹脂を混合混練してなる粒状乃至粉状の成形
材料とを用意し、前記成形材料を中心層に位置す
るようにプリプレグで挾んで加熱加圧することを
特徴とするものである。
作 用
本発明では、中心層が成形材料で構成されるた
め、その分シート状基材の使用量が減つて低コス
トとなり、絶縁板の機械的強度も両表面に配置さ
れたシート状基材で十分に確保される。
実施例
本発明で使用するシート状基材とは、紙、ガラ
ス布、綿布、ポリエステル布などであり、これに
フエノール樹脂、メラミン樹脂、ポリエステル樹
脂、エポキシ樹脂、シリコン樹脂等の熱硬化性樹
脂を含浸乾燥してプリプレグとする。また、粒状
乃至粉状成形材料は、ガラス繊維、ガラス粉、ク
レー等の無機充填材、パルプ、木粉等の有機充填
材と前記熱硬化性樹脂を混合混練して得たもので
ある。
次に本発明の一実施例を説明する。
実施例 １
ガラス繊維（長さ３mm）50重量部とエポキシ樹
脂（シエル化学製、商品名エピコート1001）40重
量部、硬化剤としてジシアンジアミド７重量部、
触媒として２−エチル−４メチルイミダゾール
0.5重量部からなる樹脂組成物とを通常の方法で
混合混練して成形材料を得た。一方、前記樹脂組
成物をメチルエチルケトンに溶解して固形分50％
のワニスとし、これをガラス布に含浸して140℃
で５分間乾燥しプリプレグを得た。
上記用意した成形材料をプリプレグで挾み金型
内で加熱加圧成形して印刷回路用絶縁板を得た。
比較例 １
実施例１における成形材料のみを用いて金型内
で加熱加圧成形し、実施例１と同一厚さの印刷回
路用絶縁板を得た。
第１表に、実施例１、比較例１で得た絶縁板の
性能を示す。
INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing an insulating board for printed circuits used as an electrical insulating material for electrical and electronic equipment. Conventional technology Insulating boards for printed circuits are made by using a sheet-like base material such as paper, cloth made of various fibers, matte, etc., and a phenol resin,
It is manufactured by stacking a plurality of prepregs obtained by impregnating and drying thermosetting resins such as melamine resin, polyester resin, epoxy resin, silicone resin, etc., and molding them under heat and pressure. Problems to be Solved by the Invention However, the above-mentioned sheet-like base material is made by processing pulp, glass fiber, etc. into paper, glass cloth, etc.
The drawback is that it requires a large number of manufacturing steps and is expensive. In order to improve this, a granular or powdery molding material made by mixing and kneading a filler such as pulp or glass fiber with a resin is injection molded or compression molded to obtain a plate-shaped molded product, and this is used as a printed circuit board. It has also been proposed to be used as an insulating board for industrial use, but when the board layer is thin, the strength such as bending strength is insufficient and it has not yet been widely put into practical use. An object of the present invention is to provide an insulating board for printed circuits that is low in cost and has sufficient mechanical strength. Means for Solving the Problems In order to achieve the above object, the present invention provides a granular or powdery molding material made by mixing and kneading a sheet-like base material impregnated with a resin and dried prepreg, a filler and a resin. The method is characterized in that the molding material is sandwiched between prepregs so as to be located in the center layer, and heated and pressurized. Effects In the present invention, since the center layer is composed of a molding material, the amount of sheet-like base material used is reduced accordingly, resulting in lower costs, and the mechanical strength of the insulating plate is improved by using the sheet-like base materials disposed on both surfaces. will be sufficiently secured. Examples The sheet-like substrate used in the present invention is paper, glass cloth, cotton cloth, polyester cloth, etc., and thermosetting resin such as phenol resin, melamine resin, polyester resin, epoxy resin, silicone resin, etc. is applied to this material. Impregnate and dry to make prepreg. The granular or powdery molding material is obtained by mixing and kneading the thermosetting resin with an inorganic filler such as glass fiber, glass powder, or clay, or an organic filler such as pulp or wood flour. Next, one embodiment of the present invention will be described. Example 1 50 parts by weight of glass fiber (length 3 mm), 40 parts by weight of epoxy resin (manufactured by Ciel Chemical Co., Ltd., trade name Epicote 1001), 7 parts by weight of dicyandiamide as a hardening agent,
2-ethyl-4methylimidazole as catalyst
A molding material was obtained by mixing and kneading 0.5 parts by weight of a resin composition using a conventional method. On the other hand, the resin composition was dissolved in methyl ethyl ketone and the solid content was 50%.
varnish, impregnated glass cloth with it and heated to 140℃.
The prepreg was dried for 5 minutes to obtain a prepreg. The molding material prepared above was sandwiched between prepregs and molded under heat and pressure in a mold to obtain an insulating board for printed circuits. Comparative Example 1 An insulating board for printed circuits having the same thickness as Example 1 was obtained by heat-pressing molding in a mold using only the molding material in Example 1. Table 1 shows the performance of the insulating plates obtained in Example 1 and Comparative Example 1.
【表】
発明の効果
第１表から明らかなように、本発明によれば機
械的強度の良好な印刷回路用絶縁板を得られ、シ
ート状基材の使用量が少ないことから安価に製造
できる点、その工業的価値は極めて大である。[Table] Effects of the Invention As is clear from Table 1, according to the present invention, an insulating board for printed circuits with good mechanical strength can be obtained, and since the amount of sheet-like base material used is small, it can be manufactured at low cost. However, its industrial value is extremely large.