【発明の詳細な説明】[Detailed description of the invention]
本発明は残留ボイドの少ない積層板に関する。
従来、ガラス繊維不織布を基材とした積層板、
或はガラス繊維織布とガラス繊維不織布を組合せ
て基材としたコンポジツト積層板が多用されてい
る。一般に、ガラス繊維不織布に使用されるガラ
ス繊維は、繊維長７〜25mm、繊維径７〜10μのも
のである。このガラス繊維不織布は密度が小さ
く、これに樹脂を含浸乾燥して得たプリプレグは
多くの気泡を内在しており、従つて、このプリプ
レグを加熱加圧成形した積層板にはボイドが残留
する。残留したボイドは、積層板を加熱したとき
に表面にふくれができる原因となつている。
一方、積層板の製造工程においても、上記ガラ
ス繊維不織布、或はそのプリプレグは、移動中に
ガラス繊維の飛散が多く、人体に『かゆみ』を与
えるなど作業環境を悪化させている。
本発明は上記の点に鑑み、ガラス繊維不織布を
基材の一部乃至全部とする積層板において残留ボ
イドをなくした積層板を提供することを目的とす
る。加えて、積層板の製造工程においても作業性
を改善するものである。
すなわち、本発明は、ガラス繊維不織布を基材
の一部乃至全部とする積層板において、前記ガラ
ス繊維不織布が、短繊維と長繊維が混合されたも
のであり、短繊維の混合比率が0.3〜0.7、短繊維
と長繊維の少なくとも一方の繊維径が５μ以下で
あることを特徴とする。ガラス繊維は、繊維長６
mm以下のものが短繊維、６mmを越えるものが長繊
維である。
ガラス短繊維の混合比率が0.3より少ないと、
積層板の製造工程でガラス繊維の飛散が多く作業
環境を悪化させる。一方、ガラス短繊維の混合比
率が0.7を越えると、ガラス繊維不織布の強度が
弱くなるため、樹脂の含浸時や成形時に基材切れ
が生じ易く積層板の製品歩留りが悪くなる。ま
た、ガラス繊維不織布の密度を高めるために、短
繊維と長繊維の少なくとも一方の繊維径を５μ以
下とする。一般に、電気絶縁用に使用するＥガラ
スは、温度による粘度変化が大きいため繊維径の
小さいものを作るのが難しく高価であるが、短繊
維と長繊維の少なくとも一方に繊維径の小さいも
のを用いることにより、経済的に有利にガラス繊
維不織布の密を高めることができる。
本発明に使用されるガラス繊維不織布は、これ
を積層板を構成する基材の全部としてもよいし、
一部に使用してもよい。本発明に使用される樹脂
は、エポキシ樹脂、フエノール樹脂、不飽和ポリ
エステル樹脂、ポリブタジエン樹脂などである
が、特に限定しない。
次に本発明の実施例を説明する。
エポキシ樹脂100重量部にジシアンジアミド４
重量部、ジメチルベンジルアミン0.2重量部を配
合したエポキシ樹脂ワニスを、平織ガラス繊維織
布、ガラス繊維不織布にそれぞれ含浸乾燥してプ
リプレグを得た。前記ガラス繊維不織布は、繊維
径３μ、繊維長３mmのガラス短繊維と繊維径８
μ、繊維長12mmのガラス長繊維をエポキシ樹脂バ
インダーで結着したものであり（バインダー含有
量13重量％）、ガラス短繊維の混合比率は0.4であ
る。平織ガラス繊維織布のプリプレグを両表面に
各１枚、中間層にガラス繊維不織布プリプレグを
配置し、更に片面に銅箔を配置して、温度160
℃、圧力25Kg／cm2で60分間積層成形して1.6mm厚
の片面銅張積層板とした。この積層板の性能、ガ
ラス繊維不織布の基材切れの有無および使用した
ガラス繊維不織布プリプレグが人体に与える影響
等を第１表に示した。
比較例 １
実施例と同様のエポキシ樹脂ワニスを平織ガラ
ス繊維織布、ガラス繊維不織布に含浸乾燥してプ
リプレグを得た。前記ガラス繊維不織布は、繊維
径８μ、繊維長３mmのガラス短繊維と繊維径８
μ、繊維長12mmのガラス長繊維をエポキシ樹脂バ
インダー結着したものであり（バインダー含有量
13重量％）、ガラス短繊維の混合比率は0.2であ
る。前間プリプレグおよ銅箔を実施例と同様に積
層成形して1.6mm厚の片面銅張積層板を得た。こ
の積層板の性能、ガラス繊維不織布の基材切れの
有無および使用したガラス繊維不織布プリプレグ
が人体に与える影響等を第１表に示した。
比較例 ２
ガラス短繊維の混合比率が0.9である以外は比
較例１と同様のガラス繊維不織布を用い、他は同
様にして1.6mm厚の片面銅張積層板を得た。この
積層板の性能、ガラス繊維不織布の基材切れの有
無およびガラス繊維不織布プリプレグが人体に与
える影響を第１表に示した。
第１表において、残留ボイドの個数は、積層板
をＥ−１／180で処理後に層間剥離を起こした箇
所の数を示す。
The present invention relates to a laminate with few residual voids. Conventionally, laminates based on glass fiber nonwoven fabric,
Alternatively, composite laminates made of a combination of glass fiber woven fabric and glass fiber nonwoven fabric as a base material are often used. Generally, the glass fibers used for glass fiber nonwoven fabrics have a fiber length of 7 to 25 mm and a fiber diameter of 7 to 10 μm. This glass fiber nonwoven fabric has a low density, and the prepreg obtained by impregnating it with a resin and drying it contains many air bubbles, and therefore, voids remain in the laminate formed by heating and press-molding this prepreg. The remaining voids are the cause of blistering on the surface of the laminate when it is heated. On the other hand, in the process of manufacturing laminates, the glass fiber nonwoven fabric or its prepreg causes many glass fibers to scatter during movement, which worsens the working environment by causing "itchiness" to the human body. In view of the above points, an object of the present invention is to provide a laminate whose base material is partly or entirely made of glass fiber nonwoven fabric, and which is free from residual voids. In addition, it also improves workability in the process of manufacturing laminates. That is, the present invention provides a laminate having a glass fiber nonwoven fabric as part or all of the base material, wherein the glass fiber nonwoven fabric is a mixture of short fibers and long fibers, and the mixing ratio of the short fibers is 0.3 to 0.3. 0.7, characterized in that the fiber diameter of at least one of the short fibers and the long fibers is 5μ or less. Glass fiber has a fiber length of 6
Short fibers are short fibers that are less than mm, and long fibers are longer than 6 mm. When the mixing ratio of short glass fibers is less than 0.3,
During the manufacturing process of laminates, a lot of glass fiber is scattered, which worsens the working environment. On the other hand, if the mixing ratio of short glass fibers exceeds 0.7, the strength of the glass fiber nonwoven fabric will be weakened, and the base material will easily break during resin impregnation or molding, resulting in poor product yield of the laminate. Further, in order to increase the density of the glass fiber nonwoven fabric, the fiber diameter of at least one of the short fibers and the long fibers is set to 5 μm or less. In general, E-glass used for electrical insulation has a large viscosity change due to temperature, so it is difficult and expensive to make small fiber diameters, but at least one of the short fibers and long fibers is made with a small fiber diameter. By doing so, the density of the glass fiber nonwoven fabric can be economically advantageously increased. The glass fiber nonwoven fabric used in the present invention may be used as the entire base material constituting the laminate, or
May be used in some parts. Resins used in the present invention include epoxy resins, phenolic resins, unsaturated polyester resins, polybutadiene resins, etc., but are not particularly limited. Next, embodiments of the present invention will be described. Dicyandiamide 4 to 100 parts by weight of epoxy resin
A prepreg was obtained by impregnating and drying a plain-woven glass fiber woven fabric and a glass fiber non-woven fabric with an epoxy resin varnish containing 0.2 parts by weight of dimethylbenzylamine. The glass fiber nonwoven fabric includes short glass fibers with a fiber diameter of 3 μm and a fiber length of 3 mm and a fiber diameter of 8
μ, long glass fibers with a fiber length of 12 mm are bound with an epoxy resin binder (binder content: 13% by weight), and the mixing ratio of short glass fibers is 0.4. One plain-woven glass fiber woven prepreg is placed on each surface, a glass fiber non-woven prepreg is placed in the middle layer, and a copper foil is placed on one side, and the temperature is 160℃.
℃ and a pressure of 25 kg/cm 2 for 60 minutes to obtain a single-sided copper-clad laminate with a thickness of 1.6 mm. Table 1 shows the performance of this laminate, the presence or absence of breakage of the base material of the glass fiber nonwoven fabric, and the influence of the glass fiber nonwoven fabric prepreg used on the human body. Comparative Example 1 A prepreg was obtained by impregnating a plain weave glass fiber woven fabric and a glass fiber nonwoven fabric with the same epoxy resin varnish as in Example and drying them. The glass fiber nonwoven fabric consists of short glass fibers with a fiber diameter of 8μ and a fiber length of 3mm, and a fiber diameter of 8μ.
μ, long glass fibers with a fiber length of 12 mm are bound with an epoxy resin binder (binder content
13% by weight), and the mixing ratio of short glass fibers is 0.2. The front prepreg and copper foil were laminated and molded in the same manner as in Examples to obtain a single-sided copper-clad laminate with a thickness of 1.6 mm. Table 1 shows the performance of this laminate, the presence or absence of breakage of the base material of the glass fiber nonwoven fabric, and the influence of the glass fiber nonwoven fabric prepreg used on the human body. Comparative Example 2 A single-sided copper-clad laminate having a thickness of 1.6 mm was obtained using the same glass fiber nonwoven fabric as in Comparative Example 1 except that the mixing ratio of short glass fibers was 0.9. Table 1 shows the performance of this laminate, the presence or absence of breakage of the base material of the glass fiber nonwoven fabric, and the influence of the glass fiber nonwoven fabric prepreg on the human body. In Table 1, the number of residual voids indicates the number of locations where delamination occurred after the laminate was treated with E-1/180.
【表】
上述のように本発明は、ガラス繊維不織布とし
て、短繊維と長繊維を混合し、短繊維の混合比率
が0.3〜0.7、短繊維と長繊維の少なくとも一方の
繊維径が５μ以下であるガラス繊維不織布を用い
ているので、積層板にボイドの発生がなくなり、
製造工程においても基材切れの防止、作業環境の
改善を図れる点その工業的価値は極めて大なるも
のである。[Table] As described above, the present invention is a glass fiber nonwoven fabric in which short fibers and long fibers are mixed, the mixing ratio of the short fibers is 0.3 to 0.7, and the fiber diameter of at least one of the short fibers and the long fibers is 5μ or less. Since we use a certain type of glass fiber non-woven fabric, there are no voids in the laminate.
Its industrial value is extremely great in that it can prevent base material breakage and improve the working environment during the manufacturing process.