JP4729832B2 - Polylactic acid crimped yarn with excellent high-temperature mechanical properties - Google Patents

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比較例１
乾燥したポリＬ−乳酸（（株）島津製作所製ラクティ５０００、Ｌ体比率95%％、Ｄ体比率5%）を、紡糸温度260℃、紡糸速度1200m/分として実施例１と同様に未延伸糸１０を得た。次いで、得られた未延伸糸を図５の装置で、第１ローラー２１の温度を80℃、第２ローラー２２の温度を120℃、第３ローラー２３の温度を室温とし、第１ローラー２１と第２ローラー２２の間の延伸倍率を2.30倍として延伸熱処理し、33dtex、36フィラメントの延伸糸を得た。次いで、ダブルツイスターを用いてこの延伸糸に5300T/mのＳ撚を施し、ボビンに巻き取った。次に、スチームセッターを用いて一旦真空状態にした後にスチームを供給してボビンごと120℃に加圧・加熱した。熱セットした撚糸を再びＺ方向に5300T/mの撚糸を行い、捲縮糸を得た。これの90℃での強度を表２に示すが、0.3cN/dtexと不充分なものであった。
【００４２】
比較例２
紡糸口金のみ12ホールのものに交換して比較例１と同じ条件で紡糸した未延伸糸を用いて、図６に示す装置において、加熱ローラー２６の温度80℃にて加熱した後、延伸ローラー３１との間で2.30倍の延伸および仮撚を加工速度300m/分にて行った。ヒーター２９は、長さ200mmであり、温度は120℃に設定した。仮撚回転子３０としては３軸ツイスターを用いた。得られた捲縮糸は33dtex、12フィラメントであった。これの90℃での強度を表２に示すが、0.3cN/dtexと不充分なものであった。
【００４３】
比較例３
比較例１で作製した延伸糸を用いて、図７に示す装置にて仮撚加工を行った。延伸ローラ３１とフィードローラー２５の速度を100m/分に設定し、ヒーター２９の温度を120℃、仮撚回転子３０としては中空スピンドルを用いた。得られた捲縮糸の90での℃強度を表２に示すが、0.4cN/dtexと不充分なものであった（図２）。 比較例４
36ホールの口金に換え、ポリマーの吐出量を変えた以外は比較例１と同様にして未延伸糸を得た後、図８に示す装置にて仮撚加工した。加工条件は延伸ローラー３１の表面速度300m/分、延伸倍率を2.30倍、ヒーター２９として1mの中空ヒーターを用い、150℃で加熱した。仮撚回転子３０としてはベルトニップツイスターを用いた。得られた84dtex、36フィラメントの仮撚加工糸の90℃での強度を表２に示すが、0.3cN/dtexと不充分なものであった。
【００４４】
比較例５
実施例５で使用したポリ乳酸を乾燥した後、220℃で溶融紡糸し、チムニー４により25℃の冷却風で糸を冷却固化させた後、集束給油ガイド６により繊維用油剤を塗布し、交絡ガイド７により糸に交絡を付与した（図３）。その後、周速3000m/分の非加熱の第１引き取りローラー８で引き取った後、非加熱の第２引き取りローラー９を介して糸を巻き取った。巻き取ったホモポリＬ乳酸繊維は非晶性であり、結晶サイズは測定できなかった。この未延伸糸１０を用いて実施例２と同様に延伸仮撚を行った。得られた84dtex、36フィラメントの仮撚加工糸の90℃での強度を表２に示すが、0.3cN/dtexと不充分なものであった。また、CR値も2%と捲縮も不充分なものであった。
【００４５】
比較例６
実施例５で5000m/分で巻き取った糸の90℃での強度を表２に示すが、0.3cN/dtexと不充分なものであった。
【００４６】
比較例７
実施例５で使用したポリ乳酸を乾燥した後、図９の装置を用い210℃で溶融紡糸し、チムニー４により15℃の冷却風で糸を冷却固化させた後、内壁温度150℃とした有効加熱長130cmの筒状加熱装置３６内を通過させ、自然冷却した後、集束給油ガイド６により繊維用油剤を塗布し、交絡ガイド７により糸に交絡を付与した。その後、周速4500m/分の非加熱の第１引き取りローラー３７で引き取った後、周速4550m/分、110℃の第２引き取りローラー３８を介し、4470m/分で巻き取り、84dtex、36フィラメントの糸１０を得た。この糸を用いて実施例２と同様に延伸仮撚を行った。得られた84dtex、36フィラメントの仮撚加工糸の90℃での強度を表２に示すが、0.3cN/dtexと不充分なものであった。
【００４７】
比較例８
筒状加熱装置３６を用いず、第１引き取りローラー３７の周速3500m/分、第２引き取りローラー３８の周速を4550m/分とし、4490m/分で巻き取った以外は比較例７と同様に紡糸を行い、さらにこの巻き取り糸を用いて、やはり比較例７と同様に延伸仮撚加工を行った。得られた84dtex、36フィラメントの仮撚加工糸の90℃での強度を表２に示すが、0.3cN/dtexと不充分なものであった。
【００４８】
【表２】

実施例６
乾燥したアルキレンオキサイドとしてビスフェノールＡエチレンオキサイド付加物を6mol%、さらにイソフタル酸を6mol%共重合した極限粘度0.65のPET（融点220℃）と、乾燥した実施例５で使用したポリ乳酸を235℃で２軸混練機を用い溶融ブレンドし、ブレンドポリマーチップを得た。この時、共重合PETのブレンド比はブレンドポリマーに対し20重量%とした。このブレンドポリマーチップのT_gは61℃とホモポリＬ乳酸の60℃とほぼ同等であった。このブレンドポリマーチップを乾燥し、紡糸温度を235℃として溶融紡糸し、チムニー４により25℃の冷却風で冷却固化させた後、集束給油ガイド６により繊維用油剤を塗布し、交絡ガイド７により糸に交絡を付与した（図３）。その後、周速1500m/分の非加熱の第１引き取りローラー８で引き取った後、非加熱の第２引き取りローラー９を介し巻き取った。この未延伸糸を図５の装置により、第１ローラー２１の温度を90℃、第２ローラー２２の温度を130℃、第３ローラー２３の温度を室温とし、第１ローラー２１と第２ローラー２２の間の延伸倍率を2.80倍として延伸熱処理した。さらにこの延伸糸２４を図４の装置により、フィードローラー１２と延伸ローラー１６の間の延伸倍率は1.05倍、ヒーター１３の温度を140℃として実施例１と同様に延伸仮撚し、165dtex、48フィラメントの仮撚加工糸を得た。得られた仮撚加工糸の物性は表３に示すが、実施例１、２のものと比較しても捲縮特性が高く仮撚加工糸として非常に優れた物であった。
また、これの広角Ｘ線回折を行ったところ、PETが配向結晶化していることが確認された。
【００４９】
実施例７
共重合PETのブレンド比を40重量%として実施例６と同様に、紡糸、延伸、延伸仮撚加工を行い84dtex、72フィラメントの仮撚加工糸を得た。得られた仮撚加工糸の物性は表３に示すが、実施例１、２のものと比較しても捲縮特性が高く仮撚加工糸として非常に優れた物であった。
また、これの広角Ｘ線回折を行ったところ、PETが配向結晶化していることが確認された。
【００５０】
実施例８
共重合PETのブレンド比を10重量%とした以外は実施例７と同様に、紡糸、延伸、延伸仮撚加工を行い84dtex、72フィラメントの仮撚加工糸を得た。得られた仮撚加工糸の物性は表３に示すが、実施例１、２のものと比較しても捲縮特性が高く仮撚加工糸として非常に優れた物であった。
また、これの広角Ｘ線回折を行ったところ、PETが配向結晶化していることが確認された。
【００５１】
実施例９
共重合PETとして分子量1000のポリエチレングリコールを4重量%、さらにイソフタル酸を6mol%共重合した極限粘度0.55のPET（融点240℃）を用い、これと乾燥した実施例１で使用したポリ乳酸を250℃で２軸混練機を用い溶融ブレンドし、ブレンドポリマーチップを得た。この時、共重合PETのブレンド比はブレンドポリマーに対し20重量%とした。このブレンドポリマーチップを乾燥し、紡糸温度を250℃とした以外は実施例６と同様に紡糸、延伸、延伸仮撚加工を行い164dtex、48フィラメントの仮撚加工糸を得た。得られた仮撚加工糸の物性は表３に示すが、実施例１、２のものと比較しても捲縮特性が高く仮撚加工糸として非常に優れた物であった。
また、これの広角Ｘ線回折を行ったところ、PETが配向結晶化していることが確認された。
【００５２】
実施例１０
共重合PETとしてアジピン酸を10mol%、さらにイソフタル酸を6mol%共重合した極限粘度0.65のPET（融点225℃）を用い、これと乾燥した実施例１で使用したポリ乳酸を235℃で２軸混練機を用い溶融ブレンドした以外は、実施例６と同様に紡糸、延伸、延伸仮撚加工を行い84dtex、48フィラメントの仮撚加工糸を得た。この時、共重合PETのブレンド比はブレンドポリマーに対し20重量%とした。得られた仮撚加工糸の物性は表３に示すが、実施例１、２のものと比較しても捲縮特性が高く仮撚加工糸として非常に優れた物であった。
【００５３】
【表３】

比較例９
乾燥した相対粘度3.4のナイロン６と乾燥した実施例１で使用したポリ乳酸を245℃で２軸混練機を用い溶融ブレンドし、ブレンドポリマーチップを得た。この時、ナイロン６のブレンド比はブレンドポリマーに対し10重量%とした。このブレンドポリマーチップを乾燥し、紡糸温度を245℃として実施例６と同様に溶融紡糸したが、ナイロン６とポリ乳酸の相溶性が不良であるため、糸切れが頻発した。巻き取った未延伸糸１０を延伸倍率を1.5倍として実施例６と同様に延伸熱処理を行ったが、延伸性は劣悪であり糸切れが頻発した。さらに、この延伸糸を用い、延伸倍率を1.30倍として実施例６と同様に延伸仮撚加工を行ったが、やはり糸切れが頻発した。得られた仮撚加工糸の90℃での強度を表４に示すが、0.2cN/dtexと不充分なものであった。
【００５４】
比較例１０
ポリ乳酸と完全に相溶する高T_gポリマーとして、ポリメチルメタクリレート（PMMA）をポリ乳酸にブレンドした例を示す。PMMA（住友化学社製スミペックスLG21）と乾燥した実施例５で使用したポリ乳酸を220℃で２軸混練機を用い溶融ブレンドし、ブレンドポリマーチップを得た。この時、PMMAのブレンド比はブレンドポリマーに対し50重量%とした。このブレンドポリマーチップのT_gは75℃とホモポリＬ乳酸の60℃に比べ大きく向上した。このブレンドポリマーチップを乾燥し、紡糸温度を220℃として比較例９と同様に溶融紡糸した。巻き取った未延伸糸を、延伸倍率を1.7倍として比較例９と同様に延伸熱処理を行ったが、延伸性は劣悪であり糸切れが頻発した。さらに、この延伸糸を用い、延伸倍率を1.50倍として比較例９と同様に延伸仮撚加工を行ったが、やはり糸切れが頻発した。得られた仮撚加工糸の90℃強度を表４に示すが、0.2cN/dtexと不充分なものであった。
このように、ポリマーのT_gが向上しても、必ずしも高温力学特性の向上につながるわけではなかった。
【００５５】
比較例１１
特開2000-109664号公報実施例２記載の方法で重合した重量平均分子量19万の脂肪族ポリエステルカーボネート（カーボネート単位が14%）と乾燥した光学純度99%、重量平均分子量20万のホモポリＬ乳酸を240℃で２軸混練機を用い溶融ブレンドし、ブレンドポリマーチップを得た。この時、脂肪族ポリエステルカーボネートのブレンド比はブレンドポリマーに対し50重量%とした。このブレンドポリマーチップのT_gは65℃であった。このブレンドポリマーチップを乾燥し、紡糸温度を240℃とした以外は比較例９と同様に溶融紡糸したが、脂肪族ポリエステルカーボネートとポリ乳酸の相溶性が不良であるため、糸切れが頻発した。巻き取った未延伸糸を比較例９と同様に延伸熱処理を行ったが、延伸性は劣悪であり糸切れが頻発した。さらに、この延伸糸を用い、延伸倍率を1.30倍として比較例９と同様に延伸仮撚加工を行ったが、やはり糸切れが頻発した。得られた仮撚加工糸の90℃での強度を表４に示すが、0.2cN/dtexと不充分なものであった。
【００５６】
比較例１２
乾燥した固有粘度1.45のナイロン１１と乾燥した実施例５で使用したポリ乳酸を別々に溶融し、ナイロン１１を芯成分、ホモポリＬ乳酸を鞘成分とした芯鞘複合紡糸を紡糸温度220℃で行った。この時、ナイロン１１の複合比は20重量%とした。これ以外は比較例９と同様にして紡糸、延伸、延伸仮撚加工を行った。得られた仮撚加工糸の90℃での強度を表４に示すが、0.3cN/dtexと不充分なものであった。 比較例１３
ナイロン１１の代わりに極限粘度1.0のポリブチレンテレフタレートを用い、紡糸温度を250℃とした以外は比較例１２と同様にして紡糸、延伸、延伸仮撚加工を行った。得られた仮撚加工糸の90での℃強度を表４に示すが、0.3cN/dtexと不充分なものであった。
【００５７】
比較例１４
ナイロン１１の代わりに極限粘度0.65のPET（融点255℃）を用い、紡糸温度を290℃とした以外は比較例９と同様にして紡糸、延伸、延伸熱処理を行った。得られた仮撚加工糸の90℃での強度を表４に示すが、0.3cN/dtexと不充分なものであった。
【００５８】
【表４】

実施例１１
実施例２で得られた仮撚加工糸を用いて地組織とし、実施例３で得られた延伸糸を立毛パイル部とするトリコット編物を28ゲージのトリコット編機を用いて64コースの編密度で製編し、自動車内装縫製加工用布帛生機を得た。そして、常法にしたがい精練、染色し、これをシート表皮材に用い、カーシートを作製した。これを用いた乗用車を３ヶ月使用したが、毛玉等の外観変化はなく、優れた耐久性を示した。また、このカーシートはソフトな風合いを有し、高級感に富むものであった。
【００５９】
比較例１５
比較例５で得られた仮撚加工糸からなる原糸を地組織とし、比較例３で得られた延伸糸を立毛パイル部として実施例１１と同様にしてカーシートを作製した。そして、実施例１１と同様に車のカーシートとして３ヶ月の使用テストを行ったが、シートに毛玉が多量に発生し耐久性に劣るものであった。
【００６０】
実施例１２
実施例３で得られた延伸糸をフロント糸に使用し、実施例２で得られた仮撚加工糸をバック糸に使用し、28ゲージのトリコット編機を用いて64コースの編密度で製編し、トリコット生地を得た。そして、常法にしたがい精練、染色、起毛加工を行ない、自動車天井用表皮材を作製した。これを用いた乗用車を３ヶ月使用したが、毛玉等の外観変化はなく、優れた耐久性を示した。また、この天井用表皮材はソフトな風合いを有し、高級感に富むものであった。
【００６１】
比較例１６
比較例３で得られた延伸糸をフロント糸に使用し、比較例５で得られた仮撚加工糸をバック糸に使用し、実施例１２と同様にして自動車天井用表皮材を作製した。そして、実施例１２と同様に車のカーシートとして３ヶ月の使用テストを行ったが、毛玉が多量に発生し耐久性に劣るものであった。
【００６２】
実施例１３
実施例２で得られた糸を経糸および緯糸に用い、平織りを作製した。経糸の糊付け乾燥を110℃で行ったが、糸が伸びるトラブルは発生しなかった。得られた平織りを常法にしたがい60℃で精練した後、140℃で中間セットを施した。さらに常法にしたがい110℃で染色した。得られた布帛は、きしみ感、ソフト感があり、衣料用として優れた風合いを有していた。
【００６３】
比較例１７
比較例３で得られた糸を経糸および緯糸に用い、平織りを作製した。経糸の糊付け乾燥を110℃で行ったが、糸が伸びてしまい乾燥が不可能であった。
【００６４】
実施例１４
吐出量、口金ホール数を変更した以外は実施例２と同様に溶融紡糸、延伸仮撚加工を行い、CR＝20%、沸収＝5%、90℃での強度＝0.9cN/dtexで165dtex、48フィラメントの仮撚加工糸を得た。
【００６５】
これを経糸および緯糸に用いて２／２ツイルを製織し、常法にしたがい布帛を染色および仕上げ加工して目付150g/m² の生地を得た。そしてこの生地を縫製し、カーテンレールを用いる片開きカーテンを作製した。これを１年間使用したが、毛玉の発生等は無く優れた耐久性を示した。
【００６６】
比較例１８
吐出量、口金ホール数を変更した以外は比較例３と同様に溶融紡糸、延伸、仮撚加工を行い、90℃での強度＝0.4cN/dtexで165dtex、48フィラメントの仮撚加工糸を得た。これを用い、実施例１４と同様にカーテンを作製し１年間使用したが、毛玉が発生し耐久性に劣るものであった。
【００６７】
実施例１５
乾燥した実施例６で使用した共重合PET（融点220℃）と、乾燥した実施例１で使用したポリ乳酸を235℃で２軸混練機を用い溶融ブレンドし、ブレンドポリマーチップを得た。この時、共重合PETのブレンド比はブレンドポリマーに対し20重量%とした。そして、このブレンドチップを紡糸温度240℃でＹ型（吐出孔長0.5mm）口金吐出孔から紡糸し、紡速800m/分で引き取った。次いで、１段目の延伸倍率を1.4倍、トータル倍率を3.5倍の条件で２段延伸を行い、さらにジェットノズルを用いて捲縮を付与してから450dtex、90フィラメントの捲縮糸を巻き取った。この捲縮糸はCR＝18%、90℃での強度＝0.8cN/dtexであった。
【００６８】
得られた捲縮糸を２本引き揃えて合糸し、下撚り（200T/m）し、それを２本用いて上撚り（200T/m）で撚り合わせ、乾熱140℃で撚り止め処理を施した後、カットパイルカーペットとして公知の方法にてタフトした。このときには、通常のレベルカットにて、1/10ゲージ、目付が1200g/m² となるようにステッチを調節してタフトした。その後、バッキングを実施した。タフトに際し、基布はアクリルとポリエチレンテレフタレートの混紡糸を用いた織り基布を使用した。これを自動車用カーマットとして１ヶ月間使用したが、毛玉の発生は無かった。
【００６９】
比較例１９
比較例１で使用したポリ乳酸ポリマーを用いて紡糸温度を260℃として、実施例１５と同様に溶融紡糸、延伸、捲縮付与を行い450dtex、90フィラメントの捲縮糸を巻き取った。この捲縮糸は、90℃での強度＝0.8cN/dtexであった。そして、これを用いて実施例１５と同様にカットパイルカーペットを作製した。これを自動車用カーマットとして１ヶ月間使用したが、毛玉が発生し耐久性に劣るものであった。
【００７０】
実施例１６
実施例６で作製した共重合PETブレンドポリ乳酸ポリマーを用い、紡糸温度220℃で中空繊維（中空率２０％）の溶融紡糸を行った。この時、口金直下に取り付けたサブチムニーにより非対称急冷を施した。これを1600m/分で引き取りトウとし、90℃水槽中で2.50倍に延伸した。そして、クリンパーを通した後、カットし、135℃で弛緩熱処理を施し、単糸繊度6dtex、繊維長60mmのカットファイバーを得た。この捲縮糸はCR＝15%、沸収＝7%、90℃での強度＝0.7cN/dtexであった。これを詰め綿に用い、掛け布団およびクッション枕を作製した。なお、糸物性値はカット前の糸で測定した。
【００７１】
【発明の効果】
本発明の高温力学特性に優れたポリ乳酸捲縮糸を使用することにより、最終製品や加工工程での耐熱性の問題点を解決でき、ポリ乳酸繊維の用途展開を大きく拡げることができる。
【図面の簡単な説明】
【図１】本発明のポリ乳酸捲縮糸の90℃での強伸度曲線を示す図である。
【図２】従来ポリ乳酸捲縮糸（比較例３）の強伸度曲線を示す図である。
【図３】紡糸、延伸装置を示す図である。
【図４】仮撚装置を示す図である。
【図５】延伸装置を示す図である。
【図６】比較例の仮撚装置を示す図である。
【図７】比較例の仮撚装置を示す図である。
【図８】比較例の仮撚装置を示す図である。
【図９】比較例の紡糸、延伸装置を示す図である。
【符号の説明】
１：スピンブロック
２：紡糸パック
３：口金
４：チムニー
５：糸条
６：集束給油ガイド
７：交絡ガイド
８：第１引き取りローラー
９：第２引き取りローラー
１０：巻き取り糸
１１：未延伸糸
１２：フィードローラー
１３：ヒーター
１４：冷却板
１５：仮撚回転子
１６：延伸ローラー
１７：セカンドヒーター
１８：デリバリーローラー
１９：仮撚加工糸
２０：フィードローラー
２１：第１ローラー
２２：第２ローラー
２３：第３ローラー
２４：延伸糸
２５：フィードローラー
２６：加熱ローラー
２７：セパレートローラー
２８：ニップローラー
２９：ヒーター
３０：仮撚回転子
３１：延伸ローラー
３２：交絡ノズル
３３：巻き取り糸
３４：リラックスローラー
３５：冷却板
３６：筒状加熱装置
３７：第１引き取りローラー
３８：第２引き取りローラー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polylactic acid crimped yarn excellent in high temperature mechanical properties.
[0002]
[Prior art]
Recently, there has been a strong demand for the development of polymer materials that can be decomposed in the natural environment in response to environmental problems on a global scale, and research and development of various polymers such as aliphatic polyesters and attempts to put them into practical use are active. It has become. Attention has been focused on polymers that are degraded by microorganisms, that is, biodegradable polymers.
[0003]
On the other hand, most of the conventional polymers are made from petroleum resources, but they have been stored in the ground since the geological era due to the fact that the petroleum resources will be depleted in the future and that they are consumed in large quantities. There is concern that carbon dioxide will be released into the atmosphere and global warming will become more serious. However, if a polymer can be synthesized using plant resources that grow by taking in carbon dioxide from the atmosphere, it is possible not only to suppress global warming by carbon dioxide circulation, but also to solve the problem of resource depletion at the same time. . For this reason, attention has been focused on polymers using plant resources as raw materials, that is, polymers using biomass.
[0004]
From the above two points, biodegradable polymers using biomass attract great attention and are expected to replace conventional polymers made from petroleum resources. However, biodegradable polymers using biomass generally have problems such as low mechanical properties and heat resistance and high cost. As a biodegradable polymer using biomass that can solve these problems, polylactic acid is currently attracting the most attention. Polylactic acid is a polymer made from lactic acid obtained by fermenting starch extracted from plants. Among biodegradable polymers using biomass, it has the best balance of mechanical properties, heat resistance, and cost. And development of the fiber using this is performed at a rapid pitch.
[0005]
The development of polylactic acid fibers is preceded by agricultural materials and civil engineering materials that make use of biodegradability, but it is expected to be applied to interior materials such as automobile interior materials and curtains and carpets as large-scale applications that follow. Has been. For these applications, polylactic acid crimped yarn is indispensable for imparting bulkiness and stretchability, but especially in automobile interior materials, the interior temperature in summer exceeds 80 ° C, so mechanical properties at high temperatures Was also sought.
[0006]
However, polylactic acid fiber has a glass transition temperature (T_g) When the temperature exceeds 60 ° C., there is a problem that the strength rapidly decreases. As a polylactic acid crimped yarn, for example, a polylactic acid false twisted yarn is described in Japanese Patent Application Laid-Open No. 2000-290845. When the strength at 90 ° C. is measured, it is 0.4 cN / dtex or less and can be used practically. There was nothing (Fig. 2).
[0007]
For this reason, in order to develop polylactic acid crimped yarns into automobile interior materials, it was essential to improve the strength at 90 ° C. Furthermore, the conventional polylactic acid crimped yarn has not only a problem in the quality of the final product at a high temperature, but also a problem in the processing process of the product. For example, when used for warp of a woven fabric, the yarn is glued for the purpose of improving the weaving property of the yarn and improving the weaving property, but when hot air drying is performed, the yarn stretches due to the tension applied to tension the warp was there. In addition, there is also a problem that the fabric stretches when tension is applied in the drying process after coating the functional drug on the fabric using the polylactic acid crimped yarn.
[0008]
As described above, polylactic acid fibers have a great limitation in application development due to the above problems. For this reason, polylactic acid fibers with improved mechanical properties at high temperatures have been desired.
[0009]
[Problems to be solved by the invention]
The present invention provides an unprecedented polylactic acid crimped yarn having excellent high-temperature mechanical properties.
[0010]
[Means for Solving the Problems]
The above-mentioned object is achieved by a polylactic acid crimped yarn excellent in high-temperature mechanical properties in which 50% by weight or more is composed of a lactic acid monomer, which simultaneously satisfies the following properties.
[0011]
Strength at 90 ℃ ≧ 0.5cN / dtex
CR ≧ 10%
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The polylactic acid referred to in the present invention means a product obtained by polymerizing lactic acid, and the optical purity of the L-form or D-form is preferably 90% or more, since the melting point is high. Moreover, in the range which does not impair the property of polylactic acid, you may copolymerize components other than lactic acid, or may contain additives, such as a polymer other than polylactic acid, particle | grains, a flame retardant, and an antistatic agent. However, from the viewpoint of biomass utilization and biodegradability, it is important that the lactic acid monomer is 50% by weight or more as a polymer. The lactic acid monomer is preferably 75% by weight or more, more preferably 96% by weight or more. In addition, the molecular weight of the polylactic acid polymer is preferably 50,000 to 500,000 in terms of weight average molecular weight, because the balance between mechanical properties and yarn-making property is good.
[0013]
In the polylactic acid crimped yarn of the present invention, it is important that the strength at 90 ° C. is 0.5 cN / dtex or more. Here, the strength at 90 ° C. can be obtained by conducting a tensile test of the crimped yarn at 90 ° C. and reading the maximum point stress in the strong elongation curve diagram. It has been found that if the strength at 90 ° C. is 0.5 cN / dtex or more, the quality of the product when used as an automobile interior material and the process passability in the processing process of the product can be improved. The strength at 90 ° C. is preferably 0.8 cN / dtex or more.
[0014]
In the polylactic acid crimped yarn of the present invention, if the boiling yield is 0 to 18%, the dimensional stability of the fiber and the fiber product is good and preferable. The boiling yield is more preferably 3 to 10%, still more preferably 3 to 6%.
[0015]
In the polylactic acid crimped yarn of the present invention, it is important that the CR value, which is an indicator of crimp characteristics, is 10% or more. When the CR value is 10% or more, sufficient bulkiness and stretchability can be obtained in the final product. The CR value is preferably 15% or more, more preferably 20% or more.
[0016]
In addition, in order to maintain sufficiently high process passability and mechanical strength of the product when the polylactic acid crimped yarn is made into a fiber product, the strength of the polylactic acid crimped yarn of the present invention at room temperature is 2.0 cN / dtex or more. It is preferable that Further, when the polylactic acid crimped yarn of the present invention has an elongation at room temperature of 15 to 50%, it is preferable because processability when the polylactic acid fiber is made into a fiber product is improved.
[0017]
The polylactic acid crimped yarn of the present invention is preferably a false twisted yarn, but may of course be a side-by-side composite yarn, a mechanical crimped yarn, or an indented crimped yarn. Further, not only long fibers but also short fibers and spun yarns using the same may be used.
[0018]
The cross-sectional shape of the polylactic acid crimped yarn of the present invention can be freely selected for a round cross-section, a hollow cross-section, a multi-leaf cross-section such as a trilobal cross-section, and other irregular cross-sections.
[0019]
The polylactic acid crimped yarn excellent in high-temperature mechanical properties of the present invention can take various fiber product forms such as woven fabrics, knitted fabrics, non-woven fabrics, and molded articles such as cups.
[0020]
Although the manufacturing method of the polylactic acid fiber excellent in the high temperature mechanical characteristic of this invention is not specifically limited, For example, the following methods are employable.
[0021]
As a first method, a method using an oriented crystallization structure by high speed spinning can be mentioned. For example, homopoly L lactic acid having a weight average molecular weight of 100,000 to 300,000 is discharged from a die at a spinning temperature of 210 to 250 ° C., and the yarn is cooled and solidified by cooling air. Thereafter, an oil agent for fibers is applied, taken up at a high speed, and wound up as it is. At this time, it is preferable to determine the take-up speed so that the crystal size of the wound polylactic acid fiber in the (200) plane direction is 6 nm or more. Then, the polylactic acid fiber crystallized by high speed spinning is stretched and false twisted at a heater temperature of 110 ° C. or higher, and heat-treated with a second heater as necessary. The reason why the high-temperature mechanical properties are greatly improved by this method compared to the conventional polylactic acid false twisted yarn is not well understood, but by restructuring the fiber structure generated by high-speed spinning while breaking it by redrawing, It is thought that a different structure is expressed from the polylactic acid crimped yarn and the high-speed spun polylactic acid fiber. Use of this method is preferable because it does not impair the biodegradability of polylactic acid.
[0022]
As a second method, a method of blending poly (lactic acid) with polyethylene terephthalate (PET) copolymerized with alkylene diol, bisphenol A derivative, or the like can be mentioned. For example, such copolymerized PET is melt blended with homopoly L lactic acid having a weight average molecular weight of 100,000 to 300,000, then discharged from a die at a spinning temperature of 210 to 250 ° C., and the yarn is cooled and solidified by cooling air. Thereafter, an oil agent for fibers is applied and taken up, and wound up as it is. The blended polylactic acid fiber is further stretched false-twisted at a heater temperature of 110 ° C. or higher, and heat-treated with a second heater as necessary. At this time, the blending ratio of the copolymerized PET is preferably 25% by weight or less in consideration of the biodegradability of polylactic acid. Further, it is preferable that the copolymerization PET has a melting point of 230 ° C. or lower, because the melt blending temperature with polylactic acid can be lowered, so that thermal decomposition of polylactic acid can be suppressed. Usually, aromatic polyester such as PET and polybutylene terephthalate (PBT) and nylon are not compatible with polylactic acid at all, and these blend polymers usually cannot be spun. The present inventors have found that the compatibility with polylactic acid is remarkably improved by copolymerization. In order to improve the compatibility with polylactic acid and maintain the crystallinity of copolymerized PET, the copolymerization ratio of alkylene diol or bisphenol A derivative to PET should be 2 to 15 mol% or 2 to 15% by weight. preferable. Here, the alkylene diol includes, for example, an alkylene oxide polymer such as polyethylene glycol, an oligomer, a diol having a large number of carbon atoms such as neopentyl glycol, hexamethylene glycol, and the like.
[0023]
As a third method, there can be mentioned a method of blending polylactic acid with PET copolymerized with a long-chain carboxylic acid. Examples of the long chain carboxylic acid include adipic acid and sebacic acid. This also exhibits the same effect as the copolymerized PET described above. Polymer blending, spinning, and drawing false twisting can be carried out in the same manner as in the case of alkylene diol or bisphenol A derivative copolymerized PET.
[0024]
The polylactic acid crimped yarn excellent in high-temperature mechanical properties of the present invention is not only used for automobile interior materials but also for clothing such as shirts, blousons and pants, clothing materials such as cups and pads, interiors such as curtains, carpets, mats and furniture, Furthermore, it can be suitably used for industrial materials such as belts, nets, ropes, heavy cloths, bags, sewing threads, felts, non-woven fabrics, filters, and artificial turf.
[0025]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples. In addition, the measuring method in an Example used the following method.
[0026]
A. Weight average molecular weight of polylactic acid
THF (tetrohydrofuran) was mixed with the chloroform solution of the sample to obtain a measurement solution. This was measured by GPC, and the weight average molecular weight was calculated in terms of polystyrene.
[0027]
B. Intrinsic viscosity of polyester [η]
Measured in orthochlorophenol at 25 ° C.
[0028]
C. Relative and intrinsic viscosity of nylon
The relative viscosity of nylon 6 was measured at 25 ° C. by preparing a 0.01% / mL 98% sulfuric acid solution.
[0029]
The intrinsic viscosity of nylon 11 was measured at 20 ° C. by preparing a 0.5% by weight metacresol solution.
[0030]
D. Strength and elongation at room temperature
At room temperature (25 ° C.), an initial sample length = 200 mm, a pulling rate = 200 mm / min, and a load-elongation curve was obtained under the conditions shown in JIS L1013. Next, the load value at break was divided by the initial fineness, which was used as the strength, and the elongation at break was divided by the initial sample length to obtain a strong elongation curve.
[0031]
E. Strength at 90 ° C
At a measurement temperature of 90 ° C., a strong elongation curve was obtained in the same manner as in D above, and the maximum point load value was divided by the initial fineness to obtain the strength at 90 ° C.
[0032]
F. Boiling
Boiling (%) = [(L0-L1) / L0)] x 100 (%)
L0: Original length of skein measured with an initial load of 0.09cN / dtex
L1: The skein measured at L0 was treated in boiling water for 15 minutes in a substantially load-free state, and after air drying, the skein length under an initial load of 0.09 cN / dtex
G. Polymer T_g
T with 2nd run using PERKIN ELMER DSC-7_gWas measured. At this time, the sample weight was 10 mg, and the temperature elevation rate was 16 ° C./min.
[0033]
H. Polylactic acid (200) plane direction crystal size
Using a 4036A2 type X-ray diffractometer manufactured by Rigaku Corporation, the diffraction intensity in the equator direction was measured under the following conditions.
[0034]
X-ray source: Cu-Kα ray (Ni filter)
Output: 40kV x 20mA
Slit: 2mmφ-1 ° -1 °
Detector: Scintillation counter
Counting recording device: RAD-C type manufactured by Rigaku Corporation
Step scan: 0.05 ° step
Integration time: 2 seconds
The (200) plane direction crystal size L was calculated using the following Scherrer equation.
[0035]
L = Kλ / (β₀cosθ_B)
L: Crystal size (nm)
K: Constant = 1.0
λ: X-ray wavelength = 0.15418 nm
θ_B : Bragg angle
β₀= (Β_E ²-Β_I ²)^1/2
β_E: Apparent half width (measured value)
β_I: Device constant = 1.046 × 10^-2rad.
I. CR value
The crimped yarn was scraped off, treated in boiling water for 15 minutes in a substantially load-free state, and air-dried for 24 hours. The sample was immersed in water under a load equivalent to 0.088 cN / dtex (0.1 gf / d), and the skein length L′ 0 after 2 minutes was measured. Next, the skein length L′ 1 after 2 minutes was measured after exchanging with a slight load equivalent to 0.0018 cN / dtex (2 mgf / d) except for skein corresponding to 0.0088 cN / dtex in water. And CR value was calculated by the following formula.
[0036]
CR (%) = [(L'0-L'1) / L'0] x 100 (%)
Example 1
Dry weight average molecular weight 190,000, homopolylactic acid (optical purity 99% L lactic acid) is melt-spun at 240 ° C, and the yarn is cooled and solidified with a cooling air of 25 ° C by Chimney 4 and then used for fibers by the converged oiling guide 6 The oil was applied and entangled with the yarn by the entanglement guide 7 (FIG. 3). Thereafter, the yarn was taken up by the non-heated first take-up roller 8 at a peripheral speed of 5000 m / min, and then the yarn 10 was wound up through the non-heated second take-up roller 9. The crystal size in the (200) plane direction of the wound homopoly L lactic acid fiber was 7.7 nm. The undrawn yarn 10 was stretched false twisted with the apparatus shown in FIG. At this time, the temperature of the heater 13 was 130 ° C., the stretching ratio between the feed roller 12 and the stretching roller 16 was 1.30 times, the speed of the stretching roller 16 was 400 m / min, and the second heater 17 was not used. A triaxial twister was used as the false twist rotor 15. The yarn physical properties are shown in Table 1, and a false twisted yarn with good crimp characteristics and shrinkage characteristics of 84 dtex and 36 filaments was obtained. The strength at 90 ° C. was 0.8 cN / dtex, indicating sufficient high-temperature mechanical properties (FIG. 1).
[0037]
Example 2
Using the undrawn yarn of Example 1, the temperature of the second heater 17 was 150 ° C., the relaxation rate between the draw roller 16 and the delivery roller 18 was 6%, and false twisted yarn was obtained in the same manner as in Example 1. The yarn physical properties are shown in Table 1. The strength at 90 ° C. was 0.9 cN / dtex, indicating sufficient high-temperature mechanical properties. In addition, the boiling point was reduced to 6% or less due to the effect of the second heater.
[0038]
Example 3
The undrawn yarn of Example 1 was set at the temperature of the first roller 21 of 130 ° C., the temperature of the second roller 22 of 130 ° C., and the temperature of the third roller 23 of room temperature using the apparatus of FIG. The drawing heat treatment was performed with the draw ratio between the two rollers 22 set to 1.35 times. Further, the drawn yarn 24 was drawn and false-twisted in the same manner as in Example 2 by setting the draw ratio between the feed roller 12 and the drawn roller 16 to 1.10 times using the apparatus shown in FIG. The properties of the obtained false twisted yarn are shown in Table 1. Even when compared with those of Examples 1 and 2, the crimped yarn had high crimp characteristics and was very excellent as a false twisted yarn.
[0039]
Example 4
Spinning and drawing false twisting were carried out in the same manner as in Example 2 with the peripheral speed of the first take-up roller 8 being 4000 m / min and the drawing ratio of drawing false twisting being 1.57 times to obtain a false twisting yarn of 84 detex and 36 filaments. It was. The crystal size in the (200) plane direction of the undrawn yarn 10 was 6.8 nm. The physical properties of this false twisted yarn are shown in Table 1. The strength at 90 ° C. was 0.6 cN / dtex, indicating sufficient high-temperature mechanical properties.
[0040]
Example 5
Using homopolylactic acid having a weight average molecular weight of 140,000 (optical purity 99% L lactic acid), melt spinning at 220 ° C., spinning at a relaxation rate of 3% between the drawing roller 16 and the delivery roller 18 as in Example 2, Drawing false twisting was performed to obtain 84 dtex, 24 filament false twisted yarn. The crystal size in the (200) plane direction of the undrawn yarn was 7.7 nm. The physical property values are shown in Table 1. The strength at 90 ° C. was 0.8 cN / dtex, indicating sufficient high-temperature mechanical properties.
[0041]
[Table 1]

Comparative Example 1
Dried poly L-lactic acid (Lacty 5000 manufactured by Shimadzu Corporation, L body ratio 95%, D body ratio 5%) was unstretched in the same manner as in Example 1 at a spinning temperature of 260 ° C. and a spinning speed of 1200 m / min. Yarn 10 was obtained. Next, the obtained undrawn yarn is set to the apparatus shown in FIG. 5, the temperature of the first roller 21 is 80 ° C., the temperature of the second roller 22 is 120 ° C., the temperature of the third roller 23 is room temperature, Drawing heat treatment was performed with the draw ratio between the second rollers 22 set to 2.30 times to obtain drawn yarns of 33 dtex and 36 filaments. Next, this stretched yarn was subjected to 5300 T / m S twist using a double twister and wound on a bobbin. Next, after evacuating using a steam setter, steam was supplied and the bobbin was pressurized and heated to 120 ° C. The heat-set twisted yarn was again twisted at 5300 T / m in the Z direction to obtain a crimped yarn. The strength at 90 ° C. is shown in Table 2, which was insufficient at 0.3 cN / dtex.
[0042]
Comparative Example 2
In the apparatus shown in FIG. 6, the heating roller 26 is heated at a temperature of 80 ° C. in the apparatus shown in FIG. 2.30 times stretching and false twisting were performed at a processing speed of 300 m / min. The heater 29 was 200 mm long, and the temperature was set to 120 ° C. A triaxial twister was used as the false twist rotor 30. The crimped yarn obtained was 33 dtex, 12 filaments. The strength at 90 ° C. is shown in Table 2, which was insufficient at 0.3 cN / dtex.
[0043]
Comparative Example 3
Using the drawn yarn produced in Comparative Example 1, false twisting was performed with the apparatus shown in FIG. The speed of the drawing roller 31 and the feed roller 25 was set to 100 m / min, the temperature of the heater 29 was 120 ° C., and the false twisting rotor 30 was a hollow spindle. Table 2 shows the strength at 90 ° C. of the crimped yarn obtained, which was insufficient at 0.4 cN / dtex (FIG. 2). Comparative Example 4
An undrawn yarn was obtained in the same manner as in Comparative Example 1 except that the amount of discharged polymer was changed in place of the 36-hole die, and false twisted with the apparatus shown in FIG. The processing conditions were as follows: the surface speed of the stretching roller 31 was 300 m / min, the stretching ratio was 2.30 times, and a 1 m hollow heater was used as the heater 29 at 150 ° C. A belt nip twister was used as the false twist rotor 30. The strength at 90 ° C. of the false twisted yarn of 84 dtex and 36 filaments obtained is shown in Table 2, but it was insufficient at 0.3 cN / dtex.
[0044]
Comparative Example 5
The polylactic acid used in Example 5 was dried, melt-spun at 220 ° C., cooled and solidified with a chimney 4 with 25 ° C. cooling air, and then the fiber oil agent was applied by the converged oiling guide 6 and entangled. The yarn was entangled with the guide 7 (FIG. 3). Thereafter, the yarn was taken up by the non-heated first take-up roller 8 at a peripheral speed of 3000 m / min, and then wound around the non-heated second take-up roller 9. The wound homopoly L lactic acid fiber was amorphous and the crystal size could not be measured. Using this undrawn yarn 10, drawn false twist was performed in the same manner as in Example 2. The strength at 90 ° C. of the false twisted yarn of 84 dtex and 36 filaments obtained is shown in Table 2, but it was insufficient at 0.3 cN / dtex. The CR value was also 2%, and the crimp was insufficient.
[0045]
Comparative Example 6
The strength at 90 ° C. of the yarn wound at 5000 m / min in Example 5 is shown in Table 2, which was insufficient at 0.3 cN / dtex.
[0046]
Comparative Example 7
After the polylactic acid used in Example 5 was dried, it was melt spun at 210 ° C. using the apparatus shown in FIG. 9, the yarn was cooled and solidified with a cooling air of 15 ° C. using Chimney 4, and the inner wall temperature was 150 ° C. After passing through a cylindrical heating device 36 having a heating length of 130 cm and naturally cooling, a fiber oil agent was applied by the focused oiling guide 6, and the yarn was entangled by the entanglement guide 7. Then, after taking up with a non-heated first take-up roller 37 with a peripheral speed of 4500 m / min, it was wound at 4470 m / min through a second take-up roller 38 with a peripheral speed of 4550 m / min and 110 ° C. Yarn 10 was obtained. Using this yarn, stretch false twisting was performed in the same manner as in Example 2. The strength at 90 ° C. of the false twisted yarn of 84 dtex and 36 filaments obtained is shown in Table 2, but it was insufficient at 0.3 cN / dtex.
[0047]
Comparative Example 8
Similar to Comparative Example 7, except that the cylindrical heating device 36 was not used, the peripheral speed of the first take-up roller 37 was 3500 m / min, the peripheral speed of the second take-up roller 38 was 4550 m / min, and winding was performed at 4490 m / min. Spinning was performed, and using this wound yarn, stretch false twisting was performed in the same manner as in Comparative Example 7. The strength at 90 ° C. of the false twisted yarn of 84 dtex and 36 filaments obtained is shown in Table 2, but it was insufficient at 0.3 cN / dtex.
[0048]
[Table 2]

Example 6
PET (melting point 220 ° C.) having an intrinsic viscosity of 0.65 obtained by copolymerizing 6 mol% of bisphenol A ethylene oxide adduct and 6 mol% of isophthalic acid as a dried alkylene oxide, and the dried polylactic acid used in Example 5 at 235 ° C. Melt blending was performed using a biaxial kneader to obtain blend polymer chips. At this time, the blending ratio of the copolymerized PET was 20% by weight with respect to the blend polymer. T of this blend polymer chip_gWas approximately equal to 61 ° C. and 60 ° C. for homopoly-L-lactic acid. This blended polymer chip is dried, melt-spun at a spinning temperature of 235 ° C., cooled and solidified with a cooling air of 25 ° C. by chimney 4, and then a fiber oil agent is applied by a focused oiling guide 6, and a yarn is entangled by an entanglement guide 7. Was entangled (Fig. 3). Then, after taking up with the non-heated 1st take-up roller 8 of the peripheral speed of 1500 m / min, it wound up via the non-heated 2nd take-up roller 9. 5, the first roller 21 and the second roller 22 are heated at a temperature of the first roller 21 of 90 ° C., a temperature of the second roller 22 of 130 ° C., and a temperature of the third roller 23 of room temperature. The stretching heat treatment was performed at a stretching ratio of 2.80 times. Further, the drawn yarn 24 was drawn and false-twisted in the same manner as in Example 1 by setting the draw ratio between the feed roller 12 and the draw roller 16 to 1.05 times and the temperature of the heater 13 to 140 ° C. with the apparatus of FIG. A false twisted yarn of filament was obtained. The physical properties of the obtained false twisted yarn are shown in Table 3. Even when compared with those of Examples 1 and 2, the crimped yarn had high crimp characteristics and was very excellent as a false twisted yarn.
Further, when wide-angle X-ray diffraction of this was performed, it was confirmed that PET was oriented and crystallized.
[0049]
Example 7
Spinning, drawing, and drawing false twisting were carried out in the same manner as in Example 6 with a copolymer PET blend ratio of 40% by weight to obtain 84 dtex, 72 filament false twisting yarn. The physical properties of the obtained false twisted yarn are shown in Table 3. Even when compared with those of Examples 1 and 2, the crimped yarn had high crimp characteristics and was very excellent as a false twisted yarn.
Further, when wide-angle X-ray diffraction of this was performed, it was confirmed that PET was oriented and crystallized.
[0050]
Example 8
Spinning, drawing, and drawing false twisting were carried out in the same manner as in Example 7 except that the blending ratio of the copolymerized PET was set to 10% by weight to obtain a false twisted yarn of 84 dtex and 72 filaments. The physical properties of the obtained false twisted yarn are shown in Table 3. Even when compared with those of Examples 1 and 2, the crimped yarn had high crimp characteristics and was very excellent as a false twisted yarn.
Further, when wide-angle X-ray diffraction of this was performed, it was confirmed that PET was oriented and crystallized.
[0051]
Example 9
As the copolymerized PET, polyethylene glycol having a molecular weight of 4% by weight and PET having an intrinsic viscosity of 0.55 copolymerized with 6 mol% of isophthalic acid (melting point: 240 ° C.) were used. Melt blending was performed at 2 ° C. using a twin-screw kneader to obtain a blend polymer chip. At this time, the blending ratio of the copolymerized PET was 20% by weight with respect to the blend polymer. This blend polymer chip was dried, and spinning, stretching, and stretching false twisting were performed in the same manner as in Example 6 except that the spinning temperature was 250 ° C., to obtain a false twisted yarn of 164 dtex and 48 filaments. The physical properties of the obtained false twisted yarn are shown in Table 3. Even when compared with those of Examples 1 and 2, the crimped yarn had high crimp characteristics and was very excellent as a false twisted yarn.
Further, when wide-angle X-ray diffraction of this was performed, it was confirmed that PET was oriented and crystallized.
[0052]
Example 10
As the copolymerized PET, 10 mol% adipic acid and 6 mol% isophthalic acid copolymerized PET with an intrinsic viscosity of 0.65 (melting point 225 ° C) were used, and the dried polylactic acid used in Example 1 was biaxial at 235 ° C. Except for melt blending using a kneader, spinning, drawing and drawing false twisting were carried out in the same manner as in Example 6 to obtain 84 dtex, 48 filament false twisting yarn. At this time, the blending ratio of the copolymerized PET was 20% by weight with respect to the blend polymer. The physical properties of the obtained false twisted yarn are shown in Table 3. Even when compared with those of Examples 1 and 2, the crimped yarn had high crimp characteristics and was very excellent as a false twisted yarn.
[0053]
[Table 3]

Comparative Example 9
The dried nylon 6 having a relative viscosity of 3.4 and the dried polylactic acid used in Example 1 were melt blended at 245 ° C. using a biaxial kneader to obtain blend polymer chips. At this time, the blend ratio of nylon 6 was 10% by weight with respect to the blend polymer. This blended polymer chip was dried and melt-spun in the same manner as in Example 6 at a spinning temperature of 245 ° C. However, because the compatibility between nylon 6 and polylactic acid was poor, yarn breakage occurred frequently. The undrawn yarn 10 wound was subjected to a drawing heat treatment in the same manner as in Example 6 with a draw ratio of 1.5, but the drawability was poor and yarn breakage occurred frequently. Further, the drawn yarn was used and drawn false twisting was performed in the same manner as in Example 6 with a draw ratio of 1.30 times. However, yarn breakage frequently occurred. Table 4 shows the strength of the obtained false twisted yarn at 90 ° C., which was insufficient at 0.2 cN / dtex.
[0054]
Comparative Example 10
High T completely compatible with polylactic acid_gAn example in which polymethyl methacrylate (PMMA) is blended with polylactic acid as a polymer is shown. PMMA (Sumitomo Chemical Co., Ltd. Sumipex LG21) and the dried polylactic acid used in Example 5 were melt blended at 220 ° C. using a biaxial kneader to obtain blend polymer chips. At this time, the blend ratio of PMMA was 50% by weight with respect to the blend polymer. T of this blend polymer chip_gWas significantly improved compared to 75 ° C. and 60 ° C. of homopoly L-lactic acid. This blend polymer chip was dried and melt-spun as in Comparative Example 9 at a spinning temperature of 220 ° C. The undrawn yarn wound was subjected to drawing heat treatment in the same manner as in Comparative Example 9 with a draw ratio of 1.7, but the drawability was poor and yarn breakage occurred frequently. Furthermore, using this drawn yarn, the drawing false twisting process was performed in the same manner as in Comparative Example 9 with the draw ratio set to 1.50 times. However, yarn breakage frequently occurred. The 90 ° C. strength of the obtained false twisted yarn is shown in Table 4, but it was insufficient at 0.2 cN / dtex.
Thus, the polymer T_gEven if improved, it did not necessarily lead to improved high-temperature mechanical properties.
[0055]
Comparative Example 11
JP-A-2000-109664 Publication Acrylic polyester carbonate having a weight average molecular weight of 190,000 (carbonic acid unit: 14%) polymerized by the method described in Example 2 and a dried optical purity of 99% and a homopoly L lactic acid having a weight average molecular weight of 200,000 Were melt blended at 240 ° C. using a twin-screw kneader to obtain blend polymer chips. At this time, the blend ratio of the aliphatic polyester carbonate was 50% by weight with respect to the blend polymer. T of this blend polymer chip_gWas 65 ° C. This blend polymer chip was dried and melt spun in the same manner as in Comparative Example 9 except that the spinning temperature was 240 ° C. However, the thread breakage occurred frequently due to poor compatibility between the aliphatic polyester carbonate and polylactic acid. The undrawn yarn wound was subjected to a drawing heat treatment in the same manner as in Comparative Example 9, but the drawability was poor and yarn breakage occurred frequently. Further, the drawn yarn was used and drawn false twisting was performed in the same manner as in Comparative Example 9 with a draw ratio of 1.30 times. However, yarn breakage frequently occurred. Table 4 shows the strength of the obtained false twisted yarn at 90 ° C., which was insufficient at 0.2 cN / dtex.
[0056]
Comparative Example 12
The dried nylon 11 having an intrinsic viscosity of 1.45 and the dried polylactic acid used in Example 5 were melted separately, and core-sheath composite spinning using nylon 11 as a core component and homopoly L lactic acid as a sheath component was performed at a spinning temperature of 220 ° C. It was. At this time, the composite ratio of nylon 11 was 20% by weight. Except for this, spinning, stretching, and stretching false twisting were performed in the same manner as in Comparative Example 9. The strength of the obtained false twisted yarn at 90 ° C. is shown in Table 4, which was insufficient at 0.3 cN / dtex. Comparative Example 13
Spinning, drawing, and drawing false twisting were performed in the same manner as in Comparative Example 12 except that polybutylene terephthalate having an intrinsic viscosity of 1.0 was used instead of nylon 11 and the spinning temperature was 250 ° C. Table 4 shows the strength at 90 ° C. of the obtained false twisted yarn, which was insufficient at 0.3 cN / dtex.
[0057]
Comparative Example 14
Spinning, drawing, and drawing heat treatment were performed in the same manner as in Comparative Example 9 except that PET (melting point 255 ° C.) having an intrinsic viscosity of 0.65 was used instead of nylon 11 and the spinning temperature was 290 ° C. The strength of the obtained false twisted yarn at 90 ° C. is shown in Table 4, which was insufficient at 0.3 cN / dtex.
[0058]
[Table 4]

Example 11
A tricot knitted fabric using the false twisted yarn obtained in Example 2 as a ground structure and the drawn yarn obtained in Example 3 as a napped pile portion is used for a knitting density of 64 courses using a 28 gauge tricot knitting machine. The fabric raw machine for automobile interior sewing processing was obtained. Then, scouring and dyeing were performed according to a conventional method, and this was used as a sheet skin material to prepare a car seat. A passenger car using this was used for 3 months, but there was no change in the appearance of pills and the like, and excellent durability was exhibited. Moreover, this car seat had a soft texture and was rich in luxury.
[0059]
Comparative Example 15
A car seat was produced in the same manner as in Example 11 using the raw yarn made of false twisted yarn obtained in Comparative Example 5 as the ground texture and the drawn yarn obtained in Comparative Example 3 as the napped pile portion. Then, a three month use test was conducted as a car seat of a car as in Example 11, but a large amount of pills were generated on the seat and the durability was poor.
[0060]
Example 12
Using the drawn yarn obtained in Example 3 as the front yarn, the false twisted yarn obtained in Example 2 as the back yarn, and using a 28-gauge tricot knitting machine with a knitting density of 64 courses. Knitted to obtain a tricot fabric. Then, scouring, dyeing, and raising were performed according to a conventional method to produce a car roof material. A passenger car using this was used for 3 months, but there was no change in the appearance of pills and the like, and excellent durability was exhibited. Moreover, this skin material for ceiling had a soft texture and was rich in a high-class feeling.
[0061]
Comparative Example 16
Using the drawn yarn obtained in Comparative Example 3 as the front yarn and the false twisted yarn obtained in Comparative Example 5 as the back yarn, an automobile ceiling skin material was produced in the same manner as in Example 12. Then, a three month use test was conducted as a car seat for a car as in Example 12, but a large amount of pills were generated and the durability was poor.
[0062]
Example 13
A plain weave was prepared using the yarn obtained in Example 2 as warp and weft. The warp sizing and drying was performed at 110 ° C., but there was no trouble that the yarn was stretched. The obtained plain weave was scoured at 60 ° C. according to a conventional method, and then an intermediate set was applied at 140 ° C. Furthermore, it dye | stained at 110 degreeC according to the conventional method. The obtained fabric had a squeaky feeling and a soft feeling, and had an excellent texture for clothing.
[0063]
Comparative Example 17
A plain weave was prepared using the yarn obtained in Comparative Example 3 as warp and weft. The warp paste was dried at 110 ° C., but the yarn was stretched and could not be dried.
[0064]
Example 14
Except for changing the discharge amount and the number of cap holes, melt spinning and drawing false twisting were performed in the same manner as in Example 2. CR = 20%, boiling point = 5%, strength at 90 ° C. = 165 ctex / dtex A 48-filament false twisted yarn was obtained.
[0065]
Using this for warp and weft, weaving 2/2 twill, dyeing and finishing fabric according to the usual method, weight per unit 150g / m²Got the dough. And this cloth was sewed to produce a one-sided curtain using a curtain rail. Although this was used for one year, there was no generation | occurrence | production of a hairball etc. and the outstanding durability was shown.
[0066]
Comparative Example 18
Except for changing the discharge amount and the number of cap holes, melt spinning, drawing, and false twisting were performed in the same manner as in Comparative Example 3, and a 165 dtex, 48 filament false twisted yarn was obtained with a strength at 90 ° C = 0.4 cN / dtex. It was. Using this, a curtain was produced in the same manner as in Example 14 and used for one year, but pills were generated and the durability was poor.
[0067]
Example 15
The copolymerized PET (melting point 220 ° C.) used in the dried Example 6 and the polylactic acid used in the dried Example 1 were melt blended at 235 ° C. using a biaxial kneader to obtain a blend polymer chip. At this time, the blending ratio of the copolymerized PET was 20% by weight with respect to the blend polymer. The blend chip was spun from a Y-type (discharge hole length: 0.5 mm) nozzle discharge hole at a spinning temperature of 240 ° C. and taken up at a spinning speed of 800 m / min. Next, the first stage draw ratio is 1.4 times and the total ratio is 3.5 times, and the second stage is drawn, and after crimping is applied using a jet nozzle, a 450 dtex, 90 filament crimped yarn is wound. It was. This crimped yarn had CR = 18% and strength at 90 ° C. = 0.8 cN / dtex.
[0068]
Two of the obtained crimped yarns are drawn together and twisted, twisted at the bottom (200 T / m), twisted together with the upper twist (200 T / m), and twisted at a dry heat of 140 ° C. Then, it was tufted by a known method as a cut pile carpet. At this time, with a normal level cut, 1/10 gauge, basis weight 1200g / m²The stitch was adjusted so that Thereafter, backing was performed. At the time of tufting, a woven base fabric using a blended yarn of acrylic and polyethylene terephthalate was used as the base fabric. This was used for 1 month as a car mat for automobiles, but no pills were generated.
[0069]
Comparative Example 19
Using the polylactic acid polymer used in Comparative Example 1, the spinning temperature was 260 ° C., and melt spinning, drawing and crimping were performed in the same manner as in Example 15 to wind a 450 dtex, 90 filament crimped yarn. The crimped yarn had a strength at 90 ° C. = 0.8 cN / dtex. And the cut pile carpet was produced similarly to Example 15 using this. This was used for 1 month as a car mat for automobiles, but pills were generated and the durability was poor.
[0070]
Example 16
Using the copolymerized PET blend polylactic acid polymer prepared in Example 6, melt spinning of hollow fibers (hollow rate 20%) was performed at a spinning temperature of 220 ° C. At this time, asymmetric quenching was performed by a sub-chimney attached directly under the base. This was taken up at 1600 m / min as a tow and stretched 2.50 times in a 90 ° C. water bath. Then, after passing through a crimper, it was cut and subjected to relaxation heat treatment at 135 ° C. to obtain a cut fiber having a single yarn fineness of 6 dtex and a fiber length of 60 mm. This crimped yarn had CR = 15%, boiling yield = 7%, and strength at 90 ° C. = 0.7 cN / dtex. This was used for stuffed cotton to make a comforter and a cushion pillow. The yarn physical properties were measured with the yarn before cutting.
[0071]
【The invention's effect】
By using the polylactic acid crimped yarn excellent in high-temperature mechanical properties of the present invention, it is possible to solve the problem of heat resistance in the final product and the processing step, and to greatly expand the application development of the polylactic acid fiber.
[Brief description of the drawings]
FIG. 1 is a diagram showing a strong elongation curve at 90 ° C. of a polylactic acid crimped yarn of the present invention.
FIG. 2 is a diagram showing a strong elongation curve of a conventional polylactic acid crimped yarn (Comparative Example 3).
FIG. 3 is a view showing a spinning and drawing apparatus.
FIG. 4 is a view showing a false twisting device.
FIG. 5 is a view showing a stretching apparatus.
FIG. 6 is a view showing a false twisting device of a comparative example.
FIG. 7 is a view showing a false twisting device of a comparative example.
FIG. 8 is a view showing a false twisting device of a comparative example.
FIG. 9 is a view showing a spinning and drawing apparatus of a comparative example.
[Explanation of symbols]
1: Spin block
2: Spin pack
3: Base
4: Chimney
5: Yarn
6: Focused lubrication guide
7: Confounding guide
8: First take-up roller
9: Second take-up roller
10: Winding yarn
11: Undrawn yarn
12: Feed roller
13: Heater
14: Cooling plate
15: False twisting rotor
16: Stretching roller
17: Second heater
18: Delivery roller
19: False twisted yarn
20: Feed roller
21: First roller
22: Second roller
23: Third roller
24: drawn yarn
25: Feed roller
26: Heating roller
27: Separate roller
28: Nip roller
29: Heater
30: false twist rotor
31: Stretching roller
32: Entanglement nozzle
33: Winding yarn
34: Relax roller
35: Cooling plate
36: Cylindrical heating device
37: First take-up roller
38: Second take-up roller

Claims (4)

A polylactic acid crimped yarn excellent in high-temperature mechanical properties composed of 50% by weight or more of a lactic acid monomer that satisfies the following properties at the same time.
Strength at 90 ℃ ≧ 0.5cN / dtex
CR ≧ 10% The polylactic acid crimped yarn according to claim 1, having a boiling yield of 18% or less. The polylactic acid crimped yarn according to claim 1 or 2, wherein the crimped yarn is a false twisted yarn. A fiber product comprising the polylactic acid crimped yarn according to any one of claims 1 to 3 at least partially.

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