【発明の詳細な説明】[Detailed description of the invention]
〔技術分野〕
この発明は、電気絶縁用等として用いられる樹
脂含浸基材に関する。
〔背景技術〕
樹脂含浸基材は、一般に次のようにしてつくら
れる。基材を樹脂ワニスに漬ける等して樹脂ワニ
スを基材に含浸させたあと、乾燥機等により乾燥
させて樹脂含浸基材を得る。
このようにして得られた樹脂含浸基材は、所定
枚が必要に応じて金属箔とともに積層成形されて
積層板にされたり、内装用回路板や外装用金属箔
張積層板等とともに積層成形されて多層プリント
配線板にされたりする。
しかしながら、前記製法により得られた樹脂含
浸基材を用いてつくつた積層板や多層プリント配
線板等の積層製品は、耐熱性，耐湿性等の性能が
充分に満足できるものではなかつた。
〔発明の目的〕
この発明は、耐熱性，吸湿性，電気絶縁性等の
性能が優れた積層製品を製造することが可能な樹
脂含浸基材を提供することを目的としている。
〔発明の開示〕
発明者らは、前記のような樹脂含浸基材の製造
を改良することにより、この発明の目的を達成し
ようとした。そこで、まず、従来の製法により得
られる樹脂含浸基材について様々な物性を調べ
た。その結果、従来の製法により得られる樹脂含
浸基材は、気泡や樹脂未含浸部（繊維間などにあ
る）等の樹脂の浸透していない部分が大きいこと
がわかり、このような樹脂の浸透していない部分
が大きいことが、積層板等の耐熱性等の性能を低
くする原因であることがわかつた。従来、基材の
樹脂に対する含浸状態は、レジンコンテントでみ
るようにしていたがレジンコンテントは、直接樹
脂が浸透していない部分の大きさに対応するもの
ではないので、レジンコンテントが良好であつて
も樹脂の浸透していない部分が大きかつたのであ
る。
発明者らは前記のような結果を得たうえでさら
に研究を重ねた。その結果、樹脂の浸透していな
い部分の大きさを面積でみることとし、樹脂の浸
透していない部分の総面積が全面積中0.3％以下
となつた樹脂含浸基材を用いれば、性能の優れた
積層製品を得ることができるということを見出し
た。さらに、基材として厚みが0.08〜0.30mmのも
のを用いることにより、上記樹脂の浸透していな
い部分の総面積を、より一層正確かつ容易に測定
しうることを見出し、ここにこの発明を完成し
た。
したがつて、この発明は、基材に樹脂ワニスを
含浸させたのち乾燥させてなる樹脂含浸基材であ
つて、前記基材の厚みが0.08mm以上0.30mm以下で
あり、かつ、樹脂の浸透していない部分の総面積
が全面積中0.3％以下になつていることを特徴と
する樹脂含浸基材をその要旨としている。以下
に、この発明を詳しく説明する。
ここで、基材としては、ガラス布，ナイロン
布，テトロン布その他の布、樹脂ワニスとして
は、ポリイミド樹脂ワニス，ポリエステル樹脂ワ
ニス，エポキシ樹脂ワニス等、いずれも、積層板
や多層プリント配線板等の積層製品製造に一般に
用いられているものが用いられる。
この発明にかかる樹脂含浸基材をつくるにあた
つても、従来と同様、樹脂ワニスを基材に含浸さ
せたあと、基材を乾燥させて樹脂含浸基材を得る
のであるが、表面からみた樹脂の浸透していない
部分の総面積が全面積中0.3％以下、好ましくは
0.1％以下、より好ましくは0.05％以下となつた
樹脂含浸基材が得られるようにするところが従来
とは異なる。具体的な、樹脂ワニスの含浸方法と
しては、たとえば、基材を樹脂ワニス中に浸して
加圧，除圧を行う方法等があげられる。
樹脂の浸透していない部分は、たとえば、白色
度，光透過率等を調べたりＸ線を照射したりする
ことにより知ることができる。繊維中の樹脂未含
浸部は、全体的に周囲に比べて白色度が普通0.4
以上の差をもつて低くなり、光透過率も一定値以
上低くなる。気泡は、周囲に比べて白色度が普通
0.4以上の差をもつて低い線、あるいは、光透過
率が一定値以上低い線により囲まれている。ま
た、樹脂の浸透していない部分の総面積は、たと
えば、気泡の平均面積に気泡の数をかけたもの
と、繊維中の樹脂未含浸部の平均面積にその数を
かけたものとの和を求めることより得ることがで
きる。
このようにして得られた樹脂含浸基材は、樹脂
が浸透していない部分の大きさが非常に小さい。
そのため、この樹脂含浸基材を用いると、耐熱
性，吸湿性，電気絶縁性等の性能が優れた積層製
品を製造することが可能になるのである。
なお、上記のようにして樹脂の浸透していない
部分を調べる場合、より一層正確かつ容易な測定
を確実に行うために、基材の厚みは0.08mm以上
0.30mm以下となつていることが必要である。厚み
が0.08mm未満では、樹脂含浸基材全体の光透過率
あるいは白色度等が高くなり、逆に0.30mmを越え
ると全体の光透過率あるいは白色度等が低くなつ
て、いずれにおいても、気泡や樹脂未含浸部等が
ある部分と他の部分との差（有意差）が小さくな
つてしまうからである。
また、樹脂の浸透していない部分の大きさの総
面積の場合、たとえば0.3％を基準として、樹脂
含浸基材の良否の判定を行うことができる。
つぎに、実施例および比較例について説明す
る。
（実施例 １）
厚み0.15mm，幅1050mmのガラス布を、樹脂量65
％の硬化剤含有Br化エポキシ樹脂が入れられた
含浸槽内に漬け、ロールにより加圧したあと除圧
することにより、樹脂量が45％となるよう樹脂ワ
ニスを均一に含浸させた。つぎに、乾燥して樹脂
含浸基材を得た。
得られた樹脂含浸基材８枚を、圧力30Kg／cm2，
温度170℃，時間90分間の条件で積層成形し、積
層板を得た。
（実施例 ２）
厚み0.2mm，幅1050mmのガラス布を、実施例１
と同様のエポキシ樹脂が入れられた含浸槽内に漬
け、50Torrの減圧状態に２分保持した後、常圧
にすることにより、樹脂量が45％となるよう樹脂
ワニスを均一に含浸させた。つぎに、乾燥して樹
脂含浸基材を得た。
得られた樹脂含浸基材６枚を、圧力30Kg／cm2，
温度170℃，時間90分間の条件で積層成形し、積
層板を得た。
（比較例 １）
ロールにより加圧したあと除圧することを行わ
なかつたほかは実施例１と同じようにして樹脂含
浸基材をつくつた。
得られた樹脂含浸基材を使用し、実施例１と同
じ条件で積層板をつくつた。
（比較例 ２）
基材の厚みを厚0.40mmとした他は実施例１と同
じようにして樹脂含浸基材をつくつた。
得られた樹脂含浸基材を使用し、実施例１と同
じ条件で積層板をつくつた。
実施例１，２および比較例１，２の樹脂含浸基
材の樹脂の浸透していない部分の面積割合の測定
結果を第１表に示す。また、実施例１，２および
比較例１，２で得られた積層板の耐熱性（オーブ
ン耐熱性）および吸湿処理後耐熱性の測定結果お
よびボイドの有無を調べた結果も第１表に示す。
ただし、吸湿処理後耐熱性の測定は、積層板を４
時間煮沸したあと、260℃溶融半田上に載せるこ
とＡおよび260℃溶融半田に漬けることＢにより
行つた。
[Technical Field] The present invention relates to a resin-impregnated base material used for electrical insulation and the like. [Background Art] A resin-impregnated base material is generally produced as follows. After the base material is impregnated with the resin varnish by, for example, dipping the base material in the resin varnish, it is dried using a dryer or the like to obtain a resin-impregnated base material. The resin-impregnated base material obtained in this manner may be laminated into a laminate by laminating a predetermined number of sheets together with metal foil as necessary, or laminated with a circuit board for interior use, a metal foil-clad laminate for exterior use, etc. It is also used to make multilayer printed wiring boards. However, laminate products such as laminate boards and multilayer printed wiring boards made using the resin-impregnated base material obtained by the above-mentioned manufacturing method do not have sufficiently satisfactory performance such as heat resistance and moisture resistance. [Object of the Invention] The object of the present invention is to provide a resin-impregnated base material with which a laminated product with excellent properties such as heat resistance, hygroscopicity, and electrical insulation can be manufactured. DISCLOSURE OF THE INVENTION The inventors sought to achieve the objects of this invention by improving the production of resin-impregnated substrates as described above. Therefore, we first investigated various physical properties of resin-impregnated base materials obtained by conventional manufacturing methods. As a result, it was found that the resin-impregnated base material obtained by the conventional manufacturing method has large areas where the resin has not penetrated, such as air bubbles and non-resin-impregnated areas (such as between fibers). It was found that the large portion of the laminate plate that was not covered by the laminate was the cause of the poor heat resistance and other performance of the laminate. Conventionally, the state of impregnation of the resin in the base material was measured by the resin content, but since the resin content does not correspond to the size of the area where the resin has not directly penetrated, it is important to check whether the resin content is good or not. However, there was a large area where the resin had not penetrated. After obtaining the above results, the inventors conducted further research. As a result, we decided to look at the size of the part where the resin has not penetrated in terms of area, and if we use a resin-impregnated base material in which the total area of the part where the resin has not penetrated is 0.3% or less of the total area, the performance will be improved. It has been found that excellent laminated products can be obtained. Furthermore, it was discovered that by using a base material with a thickness of 0.08 to 0.30 mm, the total area of the portion where the resin has not penetrated could be measured even more accurately and easily, and this invention was hereby completed. did. Therefore, the present invention provides a resin-impregnated base material obtained by impregnating a base material with a resin varnish and then drying the base material, wherein the thickness of the base material is 0.08 mm or more and 0.30 mm or less, and the penetration of the resin is The gist of the material is a resin-impregnated base material characterized by the total area of untreated parts being 0.3% or less of the total area. This invention will be explained in detail below. Here, the base material may be glass cloth, nylon cloth, Tetron cloth or other cloth, and the resin varnish may be polyimide resin varnish, polyester resin varnish, epoxy resin varnish, etc. Those commonly used in the production of laminated products are used. In producing the resin-impregnated base material according to the present invention, the resin-impregnated base material is obtained by impregnating the base material with resin varnish and then drying the base material, as in the conventional method. The total area of the part that is not penetrated by the resin is 0.3% or less of the total area, preferably
The difference from the conventional method is that a resin-impregnated base material with a content of 0.1% or less, more preferably 0.05% or less is obtained. A specific method for impregnating the resin varnish includes, for example, a method in which the base material is immersed in the resin varnish and then pressurized and depressurized. The areas where the resin has not penetrated can be determined by, for example, examining the whiteness, light transmittance, etc., or by irradiating with X-rays. The overall whiteness of the non-resin-impregnated part of the fiber is usually 0.4 compared to the surrounding area.
The light transmittance decreases with the above difference, and the light transmittance also decreases by more than a certain value. Bubbles have a normal whiteness compared to their surroundings.
It is surrounded by a line with a low light transmittance of 0.4 or more, or a line with a low light transmittance of a certain value or more. In addition, the total area of the parts that are not impregnated with resin is, for example, the sum of the average area of air bubbles multiplied by the number of air bubbles and the average area of non-resin impregnated parts of the fiber multiplied by the number of air bubbles. You can get it by asking for it. In the resin-impregnated base material obtained in this manner, the size of the portion not penetrated by the resin is extremely small.
Therefore, by using this resin-impregnated base material, it is possible to manufacture a laminated product with excellent properties such as heat resistance, moisture absorption, and electrical insulation. In addition, when examining areas where the resin has not penetrated as described above, the thickness of the base material should be at least 0.08 mm to ensure even more accurate and easy measurement.
It is necessary that the diameter is 0.30mm or less. If the thickness is less than 0.08 mm, the light transmittance or whiteness of the entire resin-impregnated base material will be high, and if it exceeds 0.30 mm, the overall light transmittance or whiteness will be low, and in either case, bubbles may occur. This is because the difference (significant difference) between a portion including a resin-unimpregnated portion and other portions becomes small. Furthermore, in the case of the total area of the portions not penetrated by the resin, the quality of the resin-impregnated base material can be determined based on, for example, 0.3%. Next, Examples and Comparative Examples will be described. (Example 1) A glass cloth with a thickness of 0.15 mm and a width of 1050 mm was coated with a resin amount of 65 mm.
% hardening agent-containing brominated epoxy resin was placed in an impregnating bath, pressure was applied with a roll, and the pressure was then removed to uniformly impregnate the resin varnish to a resin amount of 45%. Next, it was dried to obtain a resin-impregnated base material. The eight resin-impregnated base materials obtained were heated at a pressure of 30Kg/cm 2 ,
Laminate molding was performed at a temperature of 170°C for 90 minutes to obtain a laminate. (Example 2) A glass cloth with a thickness of 0.2 mm and a width of 1050 mm was prepared in Example 1.
The sample was immersed in an impregnating tank containing the same epoxy resin as above, held at a reduced pressure of 50 Torr for 2 minutes, and then brought to normal pressure to uniformly impregnate the resin varnish to a resin content of 45%. Next, it was dried to obtain a resin-impregnated base material. The six resin-impregnated base materials obtained were heated at a pressure of 30Kg/cm 2 ,
Laminate molding was performed at a temperature of 170°C for 90 minutes to obtain a laminate. (Comparative Example 1) A resin-impregnated base material was produced in the same manner as in Example 1, except that the pressure was not removed after being pressurized with a roll. Using the obtained resin-impregnated base material, a laminate was made under the same conditions as in Example 1. (Comparative Example 2) A resin-impregnated base material was produced in the same manner as in Example 1, except that the thickness of the base material was changed to 0.40 mm. Using the obtained resin-impregnated base material, a laminate was made under the same conditions as in Example 1. Table 1 shows the measurement results of the area ratios of the resin-impregnated portions of the resin-impregnated base materials of Examples 1 and 2 and Comparative Examples 1 and 2. Table 1 also shows the measurement results of the heat resistance (oven heat resistance) and heat resistance after moisture absorption treatment of the laminates obtained in Examples 1 and 2 and Comparative Examples 1 and 2, as well as the results of examining the presence or absence of voids. .
However, when measuring the heat resistance after moisture absorption treatment, the laminate was
After boiling for an hour, A was placed on molten solder at 260°C and B was immersed in molten solder at 260°C.
〔発明の効果〕〔Effect of the invention〕
この発明にかかる樹脂含浸基材は、基材に樹脂
ワニスを含浸させたのち乾燥させてなる樹脂含浸
基材であつて、前記基材の厚みが0.08mm以上0.30
mm以下であり、かつ、樹脂の浸透していない部分
の総面積が全面積中0.3％以下になつているので、
耐熱性，吸湿性，電気絶縁性等の性能が優れた積
層製品を製造することが可能である。
The resin-impregnated base material according to the present invention is a resin-impregnated base material obtained by impregnating a base material with a resin varnish and then drying the base material, the thickness of the base material being 0.08 mm or more and 0.30 mm or more.
mm or less, and the total area of the part where the resin has not penetrated is less than 0.3% of the total area, so
It is possible to manufacture laminated products with excellent properties such as heat resistance, moisture absorption, and electrical insulation.