JPH0141743B2 - - Google Patents
Info
- Publication number
- JPH0141743B2 JPH0141743B2 JP57021255A JP2125582A JPH0141743B2 JP H0141743 B2 JPH0141743 B2 JP H0141743B2 JP 57021255 A JP57021255 A JP 57021255A JP 2125582 A JP2125582 A JP 2125582A JP H0141743 B2 JPH0141743 B2 JP H0141743B2
- Authority
- JP
- Japan
- Prior art keywords
- nonwoven fabric
- fibers
- aromatic polyamide
- web
- hot
- 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
Links
- 239000000835 fiber Substances 0.000 claims description 35
- 239000004745 nonwoven fabric Substances 0.000 claims description 33
- 239000004760 aramid Substances 0.000 claims description 28
- 229920003235 aromatic polyamide Polymers 0.000 claims description 28
- 150000001408 amides Chemical class 0.000 claims description 13
- -1 polymetaphenylene isophthalamide Polymers 0.000 claims description 13
- 239000007864 aqueous solution Substances 0.000 claims description 11
- 238000012545 processing Methods 0.000 claims description 11
- 239000002904 solvent Substances 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 239000004014 plasticizer Substances 0.000 claims description 4
- 238000007731 hot pressing Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 description 14
- 239000000463 material Substances 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 230000000704 physical effect Effects 0.000 description 6
- 238000005470 impregnation Methods 0.000 description 5
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000003825 pressing Methods 0.000 description 4
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000004744 fabric Substances 0.000 description 3
- PAMIQIKDUOTOBW-UHFFFAOYSA-N 1-methylpiperidine Chemical compound CN1CCCCC1 PAMIQIKDUOTOBW-UHFFFAOYSA-N 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- 239000004566 building material Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000012772 electrical insulation material Substances 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000012815 thermoplastic material Substances 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- AVQQQNCBBIEMEU-UHFFFAOYSA-N 1,1,3,3-tetramethylurea Chemical compound CN(C)C(=O)N(C)C AVQQQNCBBIEMEU-UHFFFAOYSA-N 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 241000264877 Hippospongia communis Species 0.000 description 1
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 1
- ZWXPDGCFMMFNRW-UHFFFAOYSA-N N-methylcaprolactam Chemical compound CN1CCCCCC1=O ZWXPDGCFMMFNRW-UHFFFAOYSA-N 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 239000012210 heat-resistant fiber Substances 0.000 description 1
- GNOIPBMMFNIUFM-UHFFFAOYSA-N hexamethylphosphoric triamide Chemical compound CN(C)P(=O)(N(C)C)N(C)C GNOIPBMMFNIUFM-UHFFFAOYSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012784 inorganic fiber Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- QZUPTXGVPYNUIT-UHFFFAOYSA-N isophthalamide Chemical compound NC(=O)C1=CC=CC(C(N)=O)=C1 QZUPTXGVPYNUIT-UHFFFAOYSA-N 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- HNJBEVLQSNELDL-UHFFFAOYSA-N pyrrolidin-2-one Chemical compound O=C1CCCN1 HNJBEVLQSNELDL-UHFFFAOYSA-N 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
- 238000004383 yellowing Methods 0.000 description 1
Landscapes
- Nonwoven Fabrics (AREA)
Description
本発明は芳香族ポリアミド不織布の製造方法に
関する。更に詳しくは実質的に配向、結晶化され
ている芳香族ポリアミド繊維より成る緻密で表面
平坦性のすぐれた芳香族ポリアミド不織布の製造
方法に関する。
従来、ポリエステル、ナイロン等の熱可塑性合
成繊維を基材として適当な方法で結合又は絡合し
て不織布を製造する事は、市場に広く出まわつて
いる入手容易な素材より面状体を作成できる利点
を有し、広く行なわれている。しかしながら、こ
れらの製品は熱可塑性繊維を使用している為、製
造過程に於ては加工性に利点を有する反面、使用
に於ては耐熱性、難燃性に乏しい欠点を有し、特
に耐熱性、難燃性が要求される建材、内装材、電
気絶縁材、軽量複合材等の分野に使用することは
困難である。
かかる耐熱性、難燃性の要求に対し、素材とし
ては芳香族ポリアミド、特にポリメタフエニレン
イソフタルアミドが優れた性能を有することが知
られている。しかしながら、ポリメタフエニレン
イソフタルアミドを始めとする芳香族ポリアミド
は熱可塑性を有せず、かかる素材を使用した面状
体作成は困難である。従来知られている物として
は、例えばポリメタフエニレンイソフタルアミド
溶液を水溶液中に分散して、特定の形状のパルプ
を作成し、このパルプと短繊維とを水中で混抄
し、乾燥後加熱加圧して得られる合成紙がある。
しかし、該合成紙はパルプと言う特殊な形状を有
するポリメタフエニレンイソフタルアミドの使用
が必須であり、この物は一般に市販されておらず
入手が極めて困難であり、仮に入手できたとして
も、普通その製法から10倍以上と言う大量の水を
含有しており、その運搬等を考えると極めて不経
済である。また、該合成紙はパルプを使用する
為、内部にボイドを有し、かつ含浸性が悪いと言
う欠点を有し、絶縁ワニス、絶縁油等の使用を必
須条件とする絶縁材料用途に対しては、含浸不良
に基因する絶縁耐力の低下並びに機器のライフ低
下をきたし望ましくない。
かかる合成紙の持つ欠点を解決する為に、パル
プを使用しない高含浸性の芳香族ポリアミド不織
布も提案されている。この様な物は次の２種に大
別される。即ち、(i)ポリエチレンテレフタレート
等の熱可塑性素材をバインダーとして並用する不
織布、(ii)使用するポリメタフエニレンイソフタル
アミド繊維の少なくとも一部に実質的に配向、結
晶化していない繊維を用いる不織布である。しか
しながら前記(i)の不織布は並用した熱可塑性素材
の為、耐熱性、難燃性が低下すると言う欠点を有
し、前記(ii)の不織布は一般に市場に無く、入手が
極めて困難な特殊なポリメタフエニレンイソフタ
ルアミド繊維を使用する欠点を有する。また、こ
れら(i)、(ii)の不織布とも表面平坦性に乏しく、且
つ緻密性に欠けると言う重大な欠点を有し、不織
布に接着剤を塗付するとか、表面コーテイング加
工等の表面の緻密性平坦性が要求される用途には
使用が困難である。
本発明者等は、市場に出まわつており、入手が
容易な実質的に配向、結晶化されている芳香族ポ
リアミド繊維を使用し、その耐熱性、難燃性を損
うことなく、含浸性と表面平坦性、緻密性と言う
相反する性能を兼ね備えた芳香族ポリアミド不織
布を得るべく鋭意検討した結果、本発明に到達し
たものである。
即ち、本発明は、配向結晶化したポリメタフエ
ニレンイソフタルアミド繊維のウエブに極性アミ
ド系溶媒又はその水溶液よりなる可塑剤を極性ア
ミド系溶媒量として１重量％以上（対繊維重量）
付着せしめ熱圧ロールを用いて温度150〜400℃、
圧力（線圧）10〜1000Kg／cm、加工速度３ｍ／
min以上で熱圧加工することによつて表面の中心
線平均粗さ（Ra）が5μｍ以下の表面平坦性を有
する芳香族ポリアミド不織布を形成することを特
徴とする製造法である。
本発明方法において不織布を構成するポリメタ
フエニレンイソフタルアミドとは、ポリマーの主
たる繰返し単位がメタフエニレンイソフタルアミ
ドであるポリマーを総称し、少量の第三成分を含
む共重合体であつても良い。
ポリメタフエニレンイソフタルアミド繊維の製
造方法としては、ポリメタフエニレンイソフタル
アミドを溶解した紡糸原液を乾式あるいは湿式あ
るいは半乾半湿のいずれかの方法で紡糸し、次い
で水洗し沸水延伸を施した後、乾燥し更にガラス
転移温度以上で延伸熱処理する工程をとる。
本発明に於てはかかる工程を経て製造され普通
に市販されている、実質的に配向、結晶化してい
る芳香族ポリアミド繊維が好ましく使用できる。
本発明において、芳香族ポリアミド繊維に対
し、小割合の他の耐熱性繊維を併用することも可
能であり、例えば芳香族ポリエステル繊維、炭素
繊維、無機繊維、ガラス繊維、金属繊維等を含む
ことができる。
また、本発明において不織布とは、不織布製造
の従来法によつて得られるシート状に抄造したも
の、又はそれに後加工を施したものを言う。具体
的には、捲縮を付与したステーブルをフラツトカ
ード又はローラカード等のカード機により開繊化
し、シート状にしたもの、長繊維のトウを積層し
たものを、針を植えた一対の末広がりベルトを用
いて幅方向に延展する、いわゆる長繊維のトウ開
繊法によつて得られたシート状物、あるいは、長
繊維をベルト状にランダムに積層することによつ
て得られるシート状物、あるいは、５〜20mm程度
の短繊維を水又は空気を用いて分散後、網上に捕
集して得られるシート状物等を、例えばニードリ
ング、接着剤処理等の手段を用い絡合もしくは結
合させたものを言う。
本発明に於て、不織布の表面の平坦性を表わす
尺度は、JIS B0601−1976に規定された表面粗さ
を示す中心線平均粗さ（Ra）を用いて記述され
る。具体的な測定方法は測定機として東京精密(株)
サーフコム30Bを用い、触針径2μ、測定力70mgで
JIS B0601−1976に準じて実施した。
Ra値は粗さ曲線から、その中心線の方向に測
定長さＬの部分を抜き取り、この抜き取り部分の
中心線をＸ軸、縦倍率の方向をＹ軸として、粗さ
曲線をＹ＝ｆ（Ｘ）で表わした時、次の式で与え
られた値でμｍ単位で表わす。
Ra＝Ｉ／Ｌ∫L O｜ｆ（ｘ）｜dx
本発明に於て不織布の緻密性を表わす尺度は密
度を使用した。密度は常法により不織布を一定面
積に切り出し、その重量を化学天秤にて0.1mgま
で測定し、厚みを厚み計（ONO SHOKKI DG
−211）により0.1μｍまで測定し求めた。
本発明によつて得られる芳香族ポリアミド不織
布のRa値は5μｍ以下であり、通常、実質的に配
向、結晶化している芳香族ポリアミド繊維シート
を熱圧加工して得られる不織布のRa値は10μｍ以
上であり、また一部配向、結晶化していない芳香
族ポリアミド繊維を共存させた芳香族ポリアミド
繊維シートを熱圧加工して得られる不織布の場合
でも、Ra値は６〜7μｍ以上であることと比較す
ると極めて表面平坦性が優れていることがわか
る。
また、本発明によつて得られる芳香族ポリアミ
ド不織布の密度は、0.6ｇ／cm3以上、好ましくは
0.7〜１ｇ／cm3であり、通常、実質的に配向、結
晶化している芳香族ポリアミド繊維シートを熱圧
加工して得られる不織布の密度は0.3〜0.4ｇ／
cm3、配向、結晶化していない芳香族ポリアミド繊
維を一部共存させたシートを熱圧加工して得られ
る不織布の場合でも密度は0.7ｇ／cm3、前記パル
プを使用した芳香族ポリアミド合成紙で密度が
0.9〜1.0ｇ／cm3であることと比較すると、極めて
緻密な構造となつていることがわかる。
この様に本発明の芳香族ポリアミド不織布は実
質的に100％繊維から成る為、本質的にパルプ使
いの合成紙より優れた含浸性を有したまま、その
表面平坦性、緻密性は、パルプ使いの合成紙並み
に優れたレベルに達している事が解る。
このようにRa値が5μｍの芳香族ポリアミド不
織布を得る方法は、素材の芳香族ポリアミド繊維
が持つ耐熱性、難燃性を損わない方法であればい
かなる方法を用いても良いが、好適には下記の方
法により製造することができる。
例えば、芳香族ポリアミド繊維からなるウエブ
に極性アミド溶媒又はその水溶液よりなる可塑剤
を付着せしめ、熱圧ロールを用い熱圧加工する方
法によつて得られる。
極性アミド溶媒としては、例えばＮ−メチル−
２−ピロリドン、Ｎ，Ｎ−ジメチルホルムアミ
ド、Ｎ，Ｎ−ジメチルアセトアミド、ジメチルス
ルホキシド、ヘキサメチルホスホルミド、テトラ
メチル尿素、Ｎ−メチルカプロラクタム、Ｎ−メ
チルピペリジンなど、或いはこれらの混合物を挙
げることができる。
前記極性アミド溶媒単独又はその水溶液の芳香
族ポリアミド繊維からなるウエブへの付着量はウ
エブに対し、極性溶媒に換算して１〜100重量％
が好ましい。
極性アミド水溶液の場合の付着量は、その濃度
によつて適宜選択すべきであるが、一般に濃度が
高い程、減らすのが好ましい。
極性アミド溶液に換算した付着量が１重量％未
満では、熱圧加工後の機械物性並びに表面平坦
性、緻密性が不充分である。付着量が増加するに
従い、熱圧加工後の機械物性、表面平坦性、緻密
性は向上するが、一方、付着量が100重量％をこ
える様になると、もはや物性の向上はわずかであ
り、極性アミド溶媒のロス及びエネルギーロスが
増大するので、コスト的に無駄である。
ウエブに極性アミド溶媒及び／又は水を付着す
る方法は、ウエブに均一に付着することができる
通常工業的に用いられている方法が使用でき、例
えばスプレー法又は含浸法等を挙げることができ
る。
本発明の不織布を得るための熱圧加工条件は、
ウエブに付着する極性アミド溶媒又はその水溶液
の付着量に影響されるので、適宜選択することに
よつて決めるのが良いが、通常温度150〜400℃、
圧力10〜1000Kg／cm、加工速度（通紙速度）３
ｍ／min以上の条件で行なう。
前記温度が150℃より低い場合は、素材が芳香
族ポリアミド繊維であるため、融着性が低く、機
械的性の充分なものが得られず、一方、400℃よ
り高い場合は、通紙速度との兼ね合いもあるが、
芳香族ポリアミド繊維が熱劣化を起こし、黄変す
る等の問題がでてくる。
前記圧力は低過ぎると融着が不充分であり、一
方、高い方はいくら高くてもかまわないが、エネ
ルギー的に無駄であり1000Kg／cmまでが好まし
い。
熱圧加工方法は、二本以上の熱圧ロールを用い
て行なうのが良い。
本発明の不織布は、実質的に配向、結晶化され
た芳香族ポリアミド繊維から構成されているため
耐熱性、難燃性にすぐれている。また、パルプを
使用しない為、合成紙と比較してボイドレスであ
り、且つ含浸性が優れている。しかもRa値、密
度に示されるごとく、表面平坦性、緻密性が極め
て優れている事が大きな特徴である。これは極性
アミド溶媒又はその水溶液を付着したウエブを熱
圧加工するために、不織布の緻密性、表面平坦性
が大幅に向上したものと考えられる。
このようにして得られた不織布は、その耐熱
性、難燃性、高含浸性及び表面平坦性を活かし電
気絶縁材料、建材、内装材、離型シート、更には
ハニカム等の軽量複合材への用途が期待される。
以下、本発明の実施例について述べる。
尚、実施例中の重合体の固有粘度は濃硫酸を用
い、濃度0.5ｇ／dl、温度30℃で測定した。
また、油含浸性は25℃大気圧下で５cm角のサン
プルを真空乾燥後、絶縁油１号（JIS規格）の油
面上におき、サンプル表面に絶縁油があらわれる
までの時間であらわした。
実施例１〜３、比較例１〜３
単糸デニール1.5de、繊維長51mmの市販ポリメ
タフエニレンイソフタルアミドスフ（商品名コー
ネツクス、延伸熱処理繊維）をシングルスカツチ
ヤーで予備開綿後、フラツトカードを２回通し、
クロスレイドウエバーでベルトコンベアー上にウ
エブを形成し、引き続きニードル機で９バーブの
針を用い、針密度84本／cm2のニードルをかけ目付
230ｇ／m2の絡合ウエブを得た。このウエブの両
面にスプレー装置を用い、Ｎ−メチル−２−ピロ
リドン５重量％水溶液を該ウエブに対し100重量
％付着した。次いで熱圧ロールを用い、種々の温
度で線圧400Kg／cm、速度８ｍ／minの条件でプ
レスし、張力をかけながら連続的に巻き取つた。
得られた不織布の物性を第１表に示す。
なお、比較例２としてニードルウエブの物性
を、比較例３として可塑剤なしの場合で温度250
℃、線圧400Kg／cm、速度８ｍ／minの条件でプ
レスした不織布の物性を第１表に示す。
強伸度はインストロン測定機を用い、チヤツク
間隔20cm、サンプル巾1.5cm、ヘツド速度10cm／
minの条件で測定した。
The present invention relates to a method for producing aromatic polyamide nonwoven fabric. More specifically, the present invention relates to a method for producing a dense aromatic polyamide nonwoven fabric with excellent surface flatness, which is made of substantially oriented and crystallized aromatic polyamide fibers. Conventionally, nonwoven fabrics have been manufactured by combining or entangling thermoplastic synthetic fibers such as polyester and nylon in an appropriate manner as a base material, and it has been possible to create planar bodies from readily available materials that are widely available on the market. It has advantages and is widely practiced. However, since these products use thermoplastic fibers, while they have an advantage in processability in the manufacturing process, they have the disadvantage of poor heat resistance and flame retardancy when used, especially in heat resistance. It is difficult to use it in fields such as building materials, interior materials, electrical insulation materials, and lightweight composite materials that require high heat resistance and flame retardancy. It is known that aromatic polyamides, particularly polymetaphenylene isophthalamide, have excellent properties as materials to meet such demands for heat resistance and flame retardancy. However, aromatic polyamides such as polymetaphenylene isophthalamide do not have thermoplasticity, and it is difficult to fabricate a planar body using such materials. Conventionally known methods include, for example, dispersing a polymetaphenylene isophthalamide solution in an aqueous solution to create a pulp of a specific shape, mixing this pulp with short fibers in water, drying and then heating. There is synthetic paper obtained by pressing.
However, this synthetic paper requires the use of polymetaphenylene isophthalamide, which has a special form called pulp, and this material is generally not commercially available and is extremely difficult to obtain. Because of its manufacturing method, it usually contains a large amount of water, more than 10 times as much, and is extremely uneconomical when transporting it. In addition, since the synthetic paper uses pulp, it has voids inside and has poor impregnation properties, so it is not suitable for insulating material applications that require the use of insulating varnish, insulating oil, etc. This is undesirable because it causes a decrease in dielectric strength due to poor impregnation and shortens the life of the equipment. In order to solve the drawbacks of such synthetic paper, highly impregnable aromatic polyamide nonwoven fabrics that do not use pulp have also been proposed. Such items are broadly classified into the following two types. That is, (i) a nonwoven fabric in which a thermoplastic material such as polyethylene terephthalate is also used as a binder, and (ii) a nonwoven fabric in which at least a portion of the polymetaphenylene isophthalamide fibers used are fibers that are not substantially oriented or crystallized. be. However, since the nonwoven fabric of (i) is a thermoplastic material, it has the disadvantage of reduced heat resistance and flame retardancy, and the nonwoven fabric of (ii) is generally not available on the market and is a special material that is extremely difficult to obtain. There are disadvantages to using polymetaphenylene isophthalamide fibers. In addition, both of these nonwoven fabrics (i) and (ii) have serious drawbacks such as poor surface flatness and lack of density. It is difficult to use in applications that require denseness and flatness. The present inventors used aromatic polyamide fibers that are substantially oriented and crystallized, which are available on the market and are easily available. The present invention was developed as a result of extensive research aimed at obtaining an aromatic polyamide nonwoven fabric that has the contradictory properties of surface flatness, surface flatness, and denseness. That is, in the present invention, a plasticizer made of a polar amide solvent or an aqueous solution thereof is added to a web of oriented crystallized polymetaphenylene isophthalamide fibers in an amount of 1% by weight or more (based on the weight of the fibers).
Temperature 150-400℃ using a hot pressure roll for adhesion.
Pressure (linear pressure) 10-1000Kg/cm, processing speed 3m/
This manufacturing method is characterized by forming an aromatic polyamide nonwoven fabric having a surface flatness with a center line average roughness (Ra) of 5 μm or less by performing hot-pressure processing at a temperature of 5 μm or more. The polymetaphenylene isophthalamide constituting the nonwoven fabric in the method of the present invention is a general term for polymers whose main repeating unit is metaphenylene isophthalamide, and may also be a copolymer containing a small amount of a third component. . As a method for producing polymetaphenylene isophthalamide fibers, a spinning stock solution in which polymetaphenylene isophthalamide was dissolved was spun using either a dry method, a wet method, or a semi-dry and semi-wet method, and then washed with water and subjected to boiling water stretching. After that, a step of drying and further stretching heat treatment at a temperature higher than the glass transition temperature is performed. In the present invention, substantially oriented and crystallized aromatic polyamide fibers produced through such a process and commonly available on the market can be preferably used. In the present invention, it is also possible to use a small proportion of other heat-resistant fibers in combination with the aromatic polyamide fibers, such as aromatic polyester fibers, carbon fibers, inorganic fibers, glass fibers, metal fibers, etc. can. Furthermore, in the present invention, the term "nonwoven fabric" refers to a fabric made into a sheet obtained by a conventional method for manufacturing a nonwoven fabric, or a fabric that is subjected to post-processing. Specifically, crimped stable is spread into a sheet using a card machine such as a flat card or roller card, and a sheet made of long fiber tow is laminated into a pair of tapered belts with needles. A sheet-like product obtained by a so-called long fiber tow spreading method in which the long fibers are stretched in the width direction, or a sheet-like product obtained by laminating long fibers randomly into a belt shape, or After dispersing short fibers of about 5 to 20 mm using water or air, a sheet-like material obtained by collecting on a net is entangled or bonded using means such as needling or adhesive treatment. say something. In the present invention, a measure representing the surface flatness of a nonwoven fabric is described using centerline average roughness (Ra), which indicates surface roughness specified in JIS B0601-1976. For the specific measurement method, use Tokyo Seimitsu Co., Ltd. as the measuring device.
Using Surfcom 30B, stylus diameter 2μ, measuring force 70mg.
It was conducted in accordance with JIS B0601-1976. The Ra value is determined by extracting a portion of measurement length L from the roughness curve in the direction of its center line, and setting the center line of this sampled portion as the X axis and the vertical magnification direction as the Y axis, and plotting the roughness curve as Y=f( X), the value given by the following formula is expressed in μm. Ra=I/L∫ L O |f(x)|dx In the present invention, density was used as a measure to express the denseness of the nonwoven fabric. To determine the density, cut out a certain area of nonwoven fabric using a conventional method, measure its weight to the nearest 0.1 mg using a chemical balance, and measure the thickness using a thickness meter (ONO SHOKKI DG).
-211) to 0.1 μm. The Ra value of the aromatic polyamide nonwoven fabric obtained by the present invention is 5 μm or less, and the Ra value of the nonwoven fabric obtained by thermopressing a substantially oriented and crystallized aromatic polyamide fiber sheet is usually 10 μm. In addition, even in the case of a nonwoven fabric obtained by heat-pressing processing an aromatic polyamide fiber sheet in which partially oriented and uncrystallized aromatic polyamide fibers coexist, the Ra value must be 6 to 7 μm or more. A comparison shows that the surface flatness is extremely excellent. Further, the density of the aromatic polyamide nonwoven fabric obtained by the present invention is 0.6 g/cm 3 or more, preferably
Normally, the density of a nonwoven fabric obtained by heat-pressing a substantially oriented and crystallized aromatic polyamide fiber sheet is 0.3 to 0.4 g/ cm3 .
cm 3 , even in the case of a nonwoven fabric obtained by heat-pressing a sheet partially coexisting with aromatic polyamide fibers that are not oriented or crystallized, the density is 0.7 g/cm 3 , and aromatic polyamide synthetic paper using the above pulp The density is
When compared with 0.9 to 1.0 g/cm 3 , it can be seen that the structure is extremely dense. As described above, since the aromatic polyamide nonwoven fabric of the present invention is made of substantially 100% fibers, it has essentially better impregnating properties than synthetic paper made from pulp, but its surface flatness and density are superior to those made from synthetic paper made from pulp. It can be seen that it has reached the same level of excellence as synthetic paper. As described above, the aromatic polyamide nonwoven fabric with an Ra value of 5 μm may be obtained by any method as long as it does not impair the heat resistance and flame retardancy of the aromatic polyamide fibers used as the raw material. can be produced by the following method. For example, it can be obtained by attaching a plasticizer made of a polar amide solvent or an aqueous solution thereof to a web made of aromatic polyamide fibers, and subjecting the web to hot pressure processing using a hot pressure roll. As a polar amide solvent, for example, N-methyl-
Mention may be made of 2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, tetramethylurea, N-methylcaprolactam, N-methylpiperidine, etc., or mixtures thereof. can. The amount of the polar amide solvent alone or its aqueous solution attached to the web made of aromatic polyamide fibers is 1 to 100% by weight in terms of polar solvent based on the web.
is preferred. The amount of adhesion in the case of a polar amide aqueous solution should be appropriately selected depending on its concentration, but generally it is preferable to reduce the amount as the concentration increases. If the adhesion amount is less than 1% by weight in terms of polar amide solution, the mechanical properties, surface flatness, and density after hot-pressure processing will be insufficient. As the amount of adhesion increases, the mechanical properties, surface flatness, and density after hot-pressure processing improve, but on the other hand, when the amount of adhesion exceeds 100% by weight, the improvement in physical properties is small and the polarity Since the loss of amide solvent and energy loss increase, it is wasteful in terms of cost. As a method for applying the polar amide solvent and/or water to the web, any method commonly used in industry that can uniformly apply the polar amide solvent and/or water to the web can be used, such as a spray method or an impregnation method. The hot-press processing conditions for obtaining the nonwoven fabric of the present invention are as follows:
It is affected by the amount of polar amide solvent or its aqueous solution attached to the web, so it is best to determine it by selecting it appropriately, but usually the temperature is 150 to 400℃,
Pressure 10-1000Kg/cm, processing speed (paper passing speed) 3
Perform the test under conditions of m/min or higher. If the temperature is lower than 150℃, the material is aromatic polyamide fiber, so the fusion properties are low and sufficient mechanical properties cannot be obtained.On the other hand, if the temperature is higher than 400℃, the paper passing speed is low. Although there is a balance between
Aromatic polyamide fibers undergo thermal deterioration, causing problems such as yellowing. If the pressure is too low, the fusion bond will be insufficient, while if it is too high, it does not matter how high it is, but it is wasteful in terms of energy, so it is preferably up to 1000 kg/cm. The hot pressing method is preferably carried out using two or more hot pressing rolls. Since the nonwoven fabric of the present invention is substantially composed of oriented and crystallized aromatic polyamide fibers, it has excellent heat resistance and flame retardancy. Furthermore, since it does not use pulp, it is void-free and has excellent impregnation properties compared to synthetic paper. Moreover, as shown by the Ra value and density, the major feature is that the surface flatness and density are extremely excellent. This is thought to be due to the fact that the web coated with the polar amide solvent or its aqueous solution was subjected to hot-pressure processing, which significantly improved the denseness and surface flatness of the nonwoven fabric. The nonwoven fabric obtained in this way takes advantage of its heat resistance, flame retardance, high impregnability, and surface flatness to be used as electrical insulation materials, building materials, interior materials, release sheets, and even lightweight composite materials such as honeycombs. Expected uses. Examples of the present invention will be described below. Incidentally, the intrinsic viscosity of the polymer in the examples was measured using concentrated sulfuric acid at a concentration of 0.5 g/dl and a temperature of 30°C. Oil impregnation was measured by vacuum drying a 5 cm square sample at 25° C. and atmospheric pressure, then placing it on the surface of insulating oil No. 1 (JIS standard), and measuring the time until the insulating oil appeared on the surface of the sample. Examples 1 to 3, Comparative Examples 1 to 3 Commercially available polymetaphenylene isophthalamide fabric (trade name: Cornex, drawn heat-treated fiber) with a single yarn denier of 1.5 de and fiber length of 51 mm was pre-opened with a single cutter, and then flat carded. Pass twice,
A cross-laid web is used to form a web on a belt conveyor, and then a needle machine is used to create a web using a 9-barb needle with a needle density of 84/ cm2 .
An entangled web of 230 g/m 2 was obtained. Using a spray device, 100% by weight of a 5% by weight aqueous solution of N-methyl-2-pyrrolidone was applied to both sides of the web. Next, using a hot press roll, the material was pressed at various temperatures at a linear pressure of 400 Kg/cm and a speed of 8 m/min, and was continuously rolled up while applying tension. Table 1 shows the physical properties of the obtained nonwoven fabric. In addition, as Comparative Example 2, the physical properties of the needle web were measured, and as Comparative Example 3, the physical properties of the needle web were measured at a temperature of 250°C without a plasticizer.
Table 1 shows the physical properties of the nonwoven fabric pressed under the conditions of ℃, linear pressure of 400 kg/cm, and speed of 8 m/min. The strength and elongation was measured using an Instron measuring machine, chuck spacing 20cm, sample width 1.5cm, head speed 10cm/
Measured under conditions of min.
【表】
実施例４〜５、比較例４
実施例１と同様にして得られたウエブに対し、
５重量％のＮ−メチル−２−ピロリドン水溶液を
第２表に示す各付着量（水溶液基準）でスプレー
した後、温度250℃、線圧400Kg／cm、速度８ｍ／
minの条件でプレスし、張力をかけながら連続的
に巻取つた。得られた不織布の物性を第２表に示
した。[Table] Examples 4 to 5, Comparative Example 4 For the web obtained in the same manner as in Example 1,
After spraying a 5% by weight N-methyl-2-pyrrolidone aqueous solution at each coating amount (based on the aqueous solution) shown in Table 2, the temperature was 250°C, the linear pressure was 400 kg/cm, and the speed was 8 m/cm.
It was pressed under the conditions of min and continuously rolled up while applying tension. The physical properties of the obtained nonwoven fabric are shown in Table 2.
Claims (1)
ミド繊維のウエブに極性アミド系溶媒又はその水
溶液よりなる可塑剤を極性アミド系溶媒量として
１重量％以上（対繊維重量）付着せしめ、熱圧ロ
ールを用いて、温度150〜400℃、圧力（線圧）10
〜1000Kg／cm、加工速度３ｍ／min以上で熱圧加
工することにより、表面の中心線平均粗さ（Ra）
が5μｍ以下の表面平坦性を有する芳香族ポリア
ミド不織布を形成することを特徴とする製造法。1 A plasticizer consisting of a polar amide solvent or an aqueous solution thereof is attached to a web of oriented crystallized polymetaphenylene isophthalamide fibers in an amount of 1% by weight or more (based on the weight of the fiber) as an amount of the polar amide solvent, and then the web is heated using a hot pressure roll. , temperature 150~400℃, pressure (linear pressure) 10
By hot-pressing processing at ~1000Kg/cm and a processing speed of 3m/min or more, the centerline average roughness (Ra) of the surface can be improved.
A manufacturing method characterized by forming an aromatic polyamide nonwoven fabric having a surface flatness of 5 μm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57021255A JPS58144155A (en) | 1982-02-15 | 1982-02-15 | Aromatic polyamide nonwoven fabric |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57021255A JPS58144155A (en) | 1982-02-15 | 1982-02-15 | Aromatic polyamide nonwoven fabric |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58144155A JPS58144155A (en) | 1983-08-27 |
| JPH0141743B2 true JPH0141743B2 (en) | 1989-09-07 |
Family
ID=12049969
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57021255A Granted JPS58144155A (en) | 1982-02-15 | 1982-02-15 | Aromatic polyamide nonwoven fabric |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58144155A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58180650A (en) * | 1982-04-19 | 1983-10-22 | 帝人株式会社 | Aromatic polyamide nonwoven fabric |
| JP2676237B2 (en) * | 1988-12-06 | 1997-11-12 | 金井 宏之 | Fiber mat for silicone rubber composite sheet |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5225173A (en) * | 1975-08-13 | 1977-02-24 | Mitsubishi Rayon Co | Manufacture of heattresistant unwoven fabric and paper |
| JPS5249307A (en) * | 1975-10-16 | 1977-04-20 | Mitsubishi Rayon Co | Process for making fireresistant sheettlike mater al |
-
1982
- 1982-02-15 JP JP57021255A patent/JPS58144155A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5225173A (en) * | 1975-08-13 | 1977-02-24 | Mitsubishi Rayon Co | Manufacture of heattresistant unwoven fabric and paper |
| JPS5249307A (en) * | 1975-10-16 | 1977-04-20 | Mitsubishi Rayon Co | Process for making fireresistant sheettlike mater al |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58144155A (en) | 1983-08-27 |
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