JPH0235409B2 - - Google Patents
Info
- Publication number
- JPH0235409B2 JPH0235409B2 JP57166480A JP16648082A JPH0235409B2 JP H0235409 B2 JPH0235409 B2 JP H0235409B2 JP 57166480 A JP57166480 A JP 57166480A JP 16648082 A JP16648082 A JP 16648082A JP H0235409 B2 JPH0235409 B2 JP H0235409B2
- Authority
- JP
- Japan
- Prior art keywords
- resin
- aromatic polyamide
- insulating material
- electrical insulating
- nonwoven fabric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229920005989 resin Polymers 0.000 claims description 15
- 239000011347 resin Substances 0.000 claims description 15
- 239000000835 fiber Substances 0.000 claims description 12
- 239000004760 aramid Substances 0.000 claims description 11
- 229920003235 aromatic polyamide Polymers 0.000 claims description 11
- 239000011810 insulating material Substances 0.000 claims description 8
- 239000004745 nonwoven fabric Substances 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 6
- 239000005011 phenolic resin Substances 0.000 claims description 4
- 239000002904 solvent Substances 0.000 claims description 4
- 150000001408 amides Chemical class 0.000 claims description 2
- 239000003822 epoxy resin Substances 0.000 claims description 2
- 239000004014 plasticizer Substances 0.000 claims description 2
- 229920000647 polyepoxide Polymers 0.000 claims description 2
- 229920001225 polyester resin Polymers 0.000 claims 1
- 239000004645 polyester resin Substances 0.000 claims 1
- 229920001721 polyimide Polymers 0.000 claims 1
- 239000009719 polyimide resin Substances 0.000 claims 1
- -1 polymetaphenylene isophthalamide Polymers 0.000 claims 1
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 9
- 238000005470 impregnation Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 5
- 229920000784 Nomex Polymers 0.000 description 4
- 239000004763 nomex Substances 0.000 description 4
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 229920001568 phenolic resin Polymers 0.000 description 3
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical compound NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 description 1
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- FDQSRULYDNDXQB-UHFFFAOYSA-N benzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC(C(Cl)=O)=C1 FDQSRULYDNDXQB-UHFFFAOYSA-N 0.000 description 1
- 125000002529 biphenylenyl group Chemical group C1(=CC=CC=2C3=CC=CC=C3C12)* 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 239000012772 electrical insulation material Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 229940018564 m-phenylenediamine Drugs 0.000 description 1
- 229920006149 polyester-amide block copolymer Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- HNJBEVLQSNELDL-UHFFFAOYSA-N pyrrolidin-2-one Chemical compound O=C1CCCN1 HNJBEVLQSNELDL-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Organic Insulating Materials (AREA)
- Insulated Conductors (AREA)
Description
〔産業上の利用分野〕
本発明は、電気絶縁材の製造法に関する特に耐
熱性に優れかつ絶縁破壊電圧が大である絶縁材料
を製造する方法に関するものである。
〔従来技術〕
近年の技術的な進歩と省エネルギーの要請か
ら、耐熱絶縁物に対する要求は著しいものがあ
る。即ち、エネルギーコストの増加と世界的資源
枯渇に対する対策とから全ての機器の小型・軽量
化が求められ、これを可能にする技術の開発が進
められている。この流れの中で電気機器もまた例
外でなく、効率向上と小型化の要請から必然的に
耐熱性の向上が求められるに至つた。
例えば、耐熱性、耐久性の向上という点から電
気機器に吸湿性、耐熱性、絶縁破壊電圧などを改
善し寿命を向上させるために、樹脂含浸した絶縁
材を用いることが提案されている。
一般に耐熱性の薄葉材料としてはフイルムと紙
とがあるが、フイルムは一般に樹脂含浸には向い
ていない。一方、紙としては芳香族ポリアミド
（アラミド）紙（例えばデユポン(株)の「ノーメツ
ククス」紙や日本アロマ(株)の「Ａテイシユー」）
などがある。
これらの素材は、確かに耐熱性に優れ、難燃性
でもあり樹脂含浸するが、その構造上含浸性は余
り良好でない。一方、比較的含浸性の良いものに
乾式紙つまり不織布があるが、これらは一般にポ
リエステルと芳香族ポリアミドから成り（例えば
日本バイリーン(株)、ペロン(株)、カールフロイデン
ベルグ(株)の製品）、その耐熱性はポリエステルに
より制約されている。何故ならば、かかるポリエ
ステルは芳香族ポリアミドの接着剤であつて、一
般に樹脂含浸させても絶縁破壊電圧（Breaking
Down Voltage＝B.D.V.）が上りにくいからで
ある。
例えば、現在最も一般に用いられている耐熱合
成絶縁紙として「Nomex410」をみると、本品の
物性データは後掲の第１表に示す通りである。こ
れに例えばフエノール樹脂を含浸させた場合、フ
エノール樹脂の含浸量とB.D.V.の関係は後掲の
第２表の通りになる。この樹脂含浸によるB.D.
V.の上昇は単に構造体に隙間が多く樹脂が充分
に浸透すればよいという事ではないと思われる。
例えば「Nomex410」より粗な構造を有する
「Nomex424」の場合には、樹脂含浸を行つても
B.D.V.の上昇ははるかに少ない（第３表参照）。
これは乾式紙（つまり不織布）の場合でも同様で
あり、例えば日本バイリーン社の「H8008CT」
の場合の物性及び樹脂含浸後のB.D.V.は後掲の
第４表に示す通りで、樹脂含浸してもB.D.V.の
増加は望めない。
〔発明が解決しようとする課題〕
本発明は、上述の耐熱合成紙の欠点を解決した
特殊な構造を有する芳香族ポリアミド不織布を基
材とする電気絶縁材を製造する方法を提供しよう
とするものである。
〔課段を解決するための手段〕
本発明は、かかる課題を解決するために、(イ)芳
香族ポリアミドの延伸熱処理した繊維と(ロ)芳香族
ポリアミドの延伸未熱処理繊維及び／又は未配向
未結晶化繊維とからなる混合ウエブに極性アミド
系溶媒を含む可塑剤をウエブに対し該溶媒量にし
て0.5〜200重量％付着せしめ、熱ロールによつて
加熱加圧して形成した、密度0.8〜1.3ｇ／cm2の不
織布に、樹脂を含浸させることを特徴とする電気
絶縁材の製造法である。
本発明に於ける芳香族ポリアミドとは、下記
(1)、(2)、(3)の構造単位よりなり
R1、R2、R3は、同一でも異なつてもよく水素
原子または炭素数３以下のアルキル基を示す。実
質的に(1)と(2)は当モルよりなる。(3)は、(1)及び(2)
と必ずしも同時に含まれていなくてもよい。
Ar1、Ar2、Ar3は芳香族性残基であり、同一で
も異なつてもよい。Ar1、Ar2、Ar3の代表例は、
パラフエニレン、メタフエニレン、ビフエニレン
または(4)式で表わされる残基を示す。
Ｙは−CH2−、
[Industrial Field of Application] The present invention relates to a method for manufacturing electrical insulating materials, and particularly to a method for manufacturing insulating materials that have excellent heat resistance and high dielectric breakdown voltage. [Prior Art] Due to recent technological advances and demands for energy conservation, there is a significant demand for heat-resistant insulators. In other words, as a countermeasure against increasing energy costs and global resource depletion, all devices are required to be made smaller and lighter, and technologies that make this possible are being developed. Electrical equipment is no exception to this trend, and demands for improved efficiency and miniaturization have inevitably led to demands for improved heat resistance. For example, from the standpoint of improving heat resistance and durability, it has been proposed to use resin-impregnated insulating materials in electrical equipment in order to improve moisture absorption, heat resistance, dielectric breakdown voltage, etc., and extend lifespan. Films and papers are generally used as heat-resistant thin materials, but films are generally not suitable for resin impregnation. On the other hand, as paper, aromatic polyamide (aramid) paper (for example, "Nometsukux" paper by Dupont Co., Ltd. and "A Teishu" by Nippon Aroma Co., Ltd.)
and so on. These materials certainly have excellent heat resistance, are flame retardant, and can be impregnated with resin, but their impregnability is not very good due to their structure. On the other hand, dry paper, or nonwoven fabric, has relatively good impregnation properties, but these are generally made of polyester and aromatic polyamide (for example, products from Nippon Vilene Co., Ltd., Perron Co., Ltd., and Karl Freudenberg Co., Ltd.). , its heat resistance is limited by polyester. This is because such polyester is an aromatic polyamide adhesive, and generally has a low dielectric breakdown voltage (Breaking voltage) even if it is impregnated with resin.
This is because the down voltage (BDV) is difficult to rise. For example, looking at "Nomex 410", which is currently the most commonly used heat-resistant synthetic insulating paper, the physical property data of this product are as shown in Table 1 below. For example, when this is impregnated with phenolic resin, the relationship between the amount of phenolic resin impregnated and BDV is as shown in Table 2 below. BD by this resin impregnation
It seems that the increase in V is not simply due to the fact that there are many gaps in the structure and the resin has to penetrate sufficiently.
For example, in the case of "Nomex424", which has a rougher structure than "Nomex410", even if resin impregnation is performed,
The increase in BDV is much smaller (see Table 3).
This is also the case with dry paper (that is, nonwoven fabric); for example, "H8008CT" by Nippon Vilene Co., Ltd.
The physical properties and BDV after resin impregnation are shown in Table 4 below, and no increase in BDV can be expected even after resin impregnation. [Problems to be Solved by the Invention] The present invention aims to provide a method for manufacturing an electrical insulating material based on an aromatic polyamide nonwoven fabric having a special structure that solves the above-mentioned drawbacks of heat-resistant synthetic paper. It is. [Means for Solving the Problems] In order to solve the problems, the present invention provides (a) drawn and heat-treated fibers of aromatic polyamide and (b) drawn and unheat-treated fibers of aromatic polyamide and/or non-oriented fibers. A mixed web consisting of uncrystallized fibers is formed by attaching a plasticizer containing a polar amide solvent to the web in an amount of 0.5 to 200% by weight based on the amount of the solvent, and heating and pressing with a hot roll to form a mixed web with a density of 0.8 to 200. This is a method for producing an electrical insulation material, which is characterized by impregnating a 1.3 g/cm 2 nonwoven fabric with a resin. The aromatic polyamide in the present invention is as follows.
Consists of structural units (1), (2), and (3) R 1 , R 2 and R 3 may be the same or different and represent a hydrogen atom or an alkyl group having 3 or less carbon atoms. Substantially, (1) and (2) consist of equimolar amounts. (3) is (1) and (2)
It does not necessarily have to be included at the same time. Ar 1 , Ar 2 and Ar 3 are aromatic residues and may be the same or different. Typical examples of Ar 1 , Ar 2 and Ar 3 are:
Indicates paraphenylene, metaphenylene, biphenylene, or a residue represented by formula (4). Y is −CH 2 −,
【式】−Ｏ−、−Ｓ−、[Formula] -O-, -S-,
以上の如き本発明方法によれば、従来品に比し
極めて大きな電気絶縁性（B.D.V.）を有するシ
ート状の電気絶縁材を得ることができる。
〔実施例〕
以下実施例を挙げ本発明をより詳細に説明す
る。なお、例中に単に「部」とあるは、特ににこ
とわらない限り重量部を表わす。
実施例 １
ｍ−フエニレンジアミン108部、イソフタル酸
クロライド197部、テレフタル酸６部より得られ
た共重合物から、Ｘ線回折による結晶配向度92％
の延伸未熱処理繊維（Ａとする）及び65％の延伸
未熱処理繊維（Ｂとする）及び未延伸未熱処理繊
維すなわち未配向未結晶化繊維（Ｃとする）を得
た。いずれも太さ1.5deであり捲縮させてから長
さ51mmに切断した。Ａを40部、Ｂ又はＣを60部の
割合で混合し、カード機を通し横方向に繊維を並
べてニードルパンチを施し、目付80ｇ／m2の結合
ウエブとした。ウエブ100部に３％Ｎ−メチル−
２−ピロリドン（NMP）水溶液100部を均一に
添付し温度280℃、線圧400Kg／cmの熱圧条件でプ
レスした。この薄葉材物の密度は1.20ｇ／cm3であ
る。これにフエノール樹脂（市販の「セメダイ
ン」＃100）の20％メチルエチルケトン（MEK）
溶液を塗布した場合のB.D.V.と塗布量の関係を
後掲の第５表に示した。
実施例２、３、比較例１
実施例１に於て用いたのと全く同じ薄葉材にエ
ポキシ樹脂を含浸させたく、シエル化学社の「エ
ピコート」828 40部、エピコート871 60部、「エ
ピキユア」Z20部の20％MEK溶液を塗布した場
合のB.D.V.と塗布量の関係を後掲の第６表に示
した。
一方、BTレジン（三菱ガス化学社、ビスマレ
イミド−トリアジン樹脂）を塗布した場合を第７
表に示した。また比較のため「Nomex」410に同
じ樹脂を含浸した場合を第７表に示した。
実施例４、比較例２
実施例１に於て用いたのと全く同じ薄葉材に
JIS2号絶縁油を含浸させた場合の油含浸量とB.
D.V.の関係を第８表に示した。油を含浸させた
場合B.D.V.の上昇は認められない。尚、同じ油
を「Nomex」410に含浸させた場合のデータも併
記した。この結果からも明白な通り、「Nomex」
410の場合はB.D.V.が上昇する。
According to the method of the present invention as described above, it is possible to obtain a sheet-shaped electrical insulating material having extremely high electrical insulation properties (BDV) compared to conventional products. [Example] The present invention will be described in more detail with reference to Examples below. In the examples, the term "parts" refers to parts by weight unless otherwise specified. Example 1 A copolymer obtained from 108 parts of m-phenylenediamine, 197 parts of isophthalic acid chloride, and 6 parts of terephthalic acid had a degree of crystal orientation of 92% by X-ray diffraction.
A stretched unheat-treated fiber (designated A), a 65% stretched unheat-treated fiber (designated B), and an undrawn unheat-treated fiber, that is, an unoriented uncrystallized fiber (designated C) were obtained. Each had a thickness of 1.5 mm and was crimped and then cut to a length of 51 mm. 40 parts of A and 60 parts of B or C were mixed, passed through a card machine, and needle-punched by arranging the fibers in the transverse direction to form a bonded web with a basis weight of 80 g/m 2 . 3% N-methyl to 100 parts of web
100 parts of 2-pyrrolidone (NMP) aqueous solution was uniformly applied and pressed under hot pressure conditions of a temperature of 280°C and a linear pressure of 400 kg/cm. The density of this thin sheet material is 1.20 g/cm 3 . Add to this 20% methyl ethyl ketone (MEK) of phenolic resin (commercially available "Cemedine"#100).
The relationship between BDV and coating amount when the solution was applied is shown in Table 5 below. Examples 2 and 3, Comparative Example 1 In order to impregnate the same thin leaf material used in Example 1 with epoxy resin, we used 40 parts of "Epicoat" 828, 60 parts of "Epicure" from Ciel Chemical Co., Ltd. The relationship between BDV and coating amount when Z20 parts of 20% MEK solution is coated is shown in Table 6 below. On the other hand, the case in which BT resin (Mitsubishi Gas Chemical Co., Ltd., bismaleimide-triazine resin) was applied was
Shown in the table. For comparison, Table 7 shows the case where "Nomex" 410 was impregnated with the same resin. Example 4, Comparative Example 2 The same thin material as used in Example 1 was used.
Oil impregnation amount and B when impregnated with JIS No. 2 insulating oil.
Table 8 shows the relationship between domestic violence and domestic violence. No increase in BDV was observed when impregnated with oil. Additionally, data is also shown when "Nomex" 410 is impregnated with the same oil. As is clear from this result, "Nomex"
If it is 410, the BDV will increase.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
第１図は本発明方法による不織布断面の走査型
電子顕微鏡写真図（倍率1000倍）、第２図は従来
の不織布断面の走査型電子顕微鏡写真図（倍率
1000倍）である。
Figure 1 is a scanning electron micrograph of a cross-section of a nonwoven fabric produced by the method of the present invention (magnification: 1000x), and Figure 2 is a scanning electron micrograph of a cross-section of a conventional nonwoven fabric (magnification of
1000 times).
Claims (1)
香族ポリアミドの延伸未熱処理繊維及び／又は未
配向未結晶化繊維とからなる混合ウエブに、極性
アミド系溶媒を含む可塑剤をウエブに対し該溶媒
量にして0.5〜200重量％付着せしめ熱ロールによ
つて加熱加圧して密度0.8〜1.3ｇ／cm3の不織布を
形成せしめ、該不織布に樹脂を含浸させることを
特徴とする電気絶縁材の製造法。 ２ 芳香族ポリアミドがポリメタフエニレンイソ
フタルアミドである特許請求の範囲第１項記載の
電気絶縁材の製造法。 ３ 樹脂として、フエノール樹脂、エポキシ樹
脂、ポリイミド樹脂及びポリエステル樹脂の群か
ら選ばれた少なくとも１種の樹脂を使用する特許
請求の範囲第１項記載の電気絶縁材の製造法。[Claims] 1. A polar amide solvent is applied to a mixed web consisting of (a) drawn heat-treated aromatic polyamide fibers and (b) drawn unheat-treated aromatic polyamide fibers and/or unoriented uncrystallized fibers. 0.5 to 200% by weight of the plasticizer contained in the solvent is attached to the web, heated and pressed with a hot roll to form a nonwoven fabric with a density of 0.8 to 1.3 g/cm 3 , and the nonwoven fabric is impregnated with resin. A method for manufacturing an electrical insulating material characterized by: 2. The method for producing an electrical insulating material according to claim 1, wherein the aromatic polyamide is polymetaphenylene isophthalamide. 3. The method for producing an electrical insulating material according to claim 1, wherein at least one resin selected from the group of phenol resin, epoxy resin, polyimide resin, and polyester resin is used as the resin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16648082A JPS5956309A (en) | 1982-09-27 | 1982-09-27 | Electric insulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16648082A JPS5956309A (en) | 1982-09-27 | 1982-09-27 | Electric insulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5956309A JPS5956309A (en) | 1984-03-31 |
| JPH0235409B2 true JPH0235409B2 (en) | 1990-08-10 |
Family
ID=15832176
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16648082A Granted JPS5956309A (en) | 1982-09-27 | 1982-09-27 | Electric insulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5956309A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0582010U (en) * | 1992-04-09 | 1993-11-05 | エスエムケイアールアンドディ株式会社 | Movable iron core type electromagnetic actuator |
| WO2020262186A1 (en) * | 2019-04-25 | 2020-12-30 | ルビコン株式会社 | Solid electrolytic capacitor and method for manufacturing same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49101897A (en) * | 1973-02-02 | 1974-09-26 | ||
| JPS5221475A (en) * | 1975-08-07 | 1977-02-18 | Mitsubishi Rayon Co | Composite |
-
1982
- 1982-09-27 JP JP16648082A patent/JPS5956309A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49101897A (en) * | 1973-02-02 | 1974-09-26 | ||
| JPS5221475A (en) * | 1975-08-07 | 1977-02-18 | Mitsubishi Rayon Co | Composite |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0582010U (en) * | 1992-04-09 | 1993-11-05 | エスエムケイアールアンドディ株式会社 | Movable iron core type electromagnetic actuator |
| WO2020262186A1 (en) * | 2019-04-25 | 2020-12-30 | ルビコン株式会社 | Solid electrolytic capacitor and method for manufacturing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5956309A (en) | 1984-03-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3868448B2 (en) | Heat resistant synthetic fiber sheet | |
| US5002637A (en) | Composite material reinforced by para-oriented aramide fiber sheet and process for preparing the same | |
| JP2655753B2 (en) | Method for producing aromatic polyamide paper with high porosity | |
| JP5640993B2 (en) | Nonwoven fabric containing polyphenylene sulfide fiber | |
| JPH0325537B2 (en) | ||
| KR102517812B1 (en) | Corona resistant resin affinity laminate | |
| WO1998056987A1 (en) | Heat-resistant fiber paper | |
| US4418241A (en) | Insulated coil | |
| EP0059866A2 (en) | Thin insulating sheet | |
| KR100601061B1 (en) | Wholly aromatic polyamide fiber synthetic paper sheet | |
| EP0836204B1 (en) | High voltage electric appliance | |
| EP0092210B1 (en) | Wholly aromatic polyamide fiber non-woven sheet and processes for producing the same | |
| JPH0235409B2 (en) | ||
| US4595457A (en) | Oil-impregnatable insulating board | |
| US5173359A (en) | Composite material for electrical applications reinforced by para-oriented aramide fibrous substance and process for preparing same | |
| JP2003096698A (en) | Heat-resistant insulating paper sheet and method for producing the same | |
| JPH10315398A (en) | Heat resistant sheet for electric insulation | |
| JPH07202362A (en) | Thermoplastic resin printed wiring board | |
| JP3588423B2 (en) | Heat-resistant fiber paper, method for producing the same, and prepreg using the heat-resistant fiber paper | |
| JPH1120083A (en) | Composite sheet and its manufacture | |
| JPH0328764B2 (en) | ||
| JP2001192955A (en) | Heat-resistant nonwoven fabric, method of producing the same, and substrate material for printed circuit board therefrom | |
| JP2986632B2 (en) | Aramid board with little hygroscopic deformation | |
| RU2084030C1 (en) | Electric insulation material | |
| JPH0140138B2 (en) |