JP3830307B2 - Method for producing molding material impregnated with thermoplastic resin - Google Patents

Description

【００３２】
さらに好ましくは、
【００３３】
【数５】

【００３４】
である。
【００３５】
ここで、δは成形材料の任意の表面における最大高さから最小高さを引いた絶対値と定義する。
【００３６】
凹凸指数δが５０μｍを超えると、成形材料を多数積層した場合に局所的な厚さ斑となるばかりか、凹凸部分によって形成されるボイドが最終製品に残存して欠陥となる場合があるからである。
【００３７】
このような凹凸指数δは、以下の手段で測定できる。例えば、株式会社キーエンス製のレーザーフォーカス式変位計で半導体レーザーを光源とする装置を用いてよい。本装置によれば直径２μｍの極小スポットを０．１μｍの分解能で計測することが可能である。
【００３８】
成形材料の断面
本発明の製造方法により得られる成形材料の他の特徴の一つは、成形材料の断面形状が実質的に平行四辺形であることである。すなわち、成形材料の厚さ（Ｔｍｍ）と幅（Ｗｍｍ）の比が下記の式で示される範囲である。
【００３９】
【数６】

【００４０】
Ｗ／Ｔが１未満であると成形材料の厚さが大きくなり、該成形材料の内部に繊維の蛇行やボイドなどの内部欠陥が生じ易いばかりか、該成形材料を加工する際に熱で容易に溶け難くなるため、最終製品の生産性が低下することになり好ましくない。また、Ｗ／Ｔが１００００を超えると成形材料の厚さが小さくなり、幅方向に目開きのない成形材料の製作が困難となる。
【００４１】
ここで、平行四辺形としては、矩形であることが製作上及びレベルアップのし易さなど利用上の面から好ましいが、矩形以外の平行四辺形であってもよい。
【００４２】
成形材料の巻き径
成形材料を巻回した場合の巻き最小直径は５０ｍｍ以上が望ましく、さらに望ましくは１５ｍｍ以上である。巻き最小直径が１５ｍｍ未満の場合には成形材料は強化繊維の切断または屈曲による破損を生ずる。従って、成形材料の荷姿は前記最小直径以上であれば問題ない。
【００４３】
成形材料の製造方法
成形材料は、以下の手段で製作することが可能である。例えば、先ず、強化繊維に熱可塑性樹脂を含浸する手段には次の各手段が列挙できる。
【００４４】
（１）強化繊維を熱可塑性樹脂粉末のサスペンジョン液中を通過させて、該強化繊維に熱可塑性樹脂を付着させ、次いで熱可塑性樹脂のガラス転移温度または融点以上の温度で熱可塑性樹脂を溶融し一体化する。該方法によれば、熱可塑性樹脂をより完全に強化繊維に含浸することが可能になる。この場合、熱可塑性樹脂粉末の平均粒子径は５〜２０μｍ程度が好ましく、熱可塑性樹脂は粉末状となるものに限定される。
【００４５】
（２）強化繊維を熱可塑性樹脂粉末の流動床中を通過させて、場合によっては熱可塑性樹脂粉末を帯電させて該強化繊維に熱可塑性樹脂を付着させ、次いで熱可塑性樹脂のガラス転移温度または融点以上の温度で熱可塑性樹脂を溶融し一体化する。該方法によれば、熱可塑性樹脂をより完全に強化繊維に含浸することが可能になる。この場合、熱可塑性樹脂粉末の平均粒子径は５〜２０μｍ程度が好ましく、熱可塑性樹脂は粉末状となるものに限定される。
【００４６】
（３）強化繊維を熱可塑性樹脂溶液中を通過させて、該強化繊維に熱可塑性樹脂を付着させ、次いで熱可塑性樹脂の溶剤を除去する。該方法によれば、熱可塑性樹脂をより完全に強化繊維に含浸することが可能になる。この場合、熱可塑性樹脂は溶剤に溶解するものに限定される。
【００４７】
（４）溶融した熱可塑性樹脂を強化繊維に押出機等で注入し、一体化する。該方法によれば、熱可塑性樹脂をより多く強化繊維に含浸することが可能になる。この場合、熱可塑性樹脂は強化繊維の表面に被覆した状態となりやすいので、樹脂の含浸工程を設けることが好ましい。
【００４８】
（５）強化繊維を熱可塑性樹脂の繊維と混紡し、次いで熱可塑性樹脂のガラス転移温度または融点以上の温度で熱可塑性樹脂を溶融し一体化する。該方法によれば、熱可塑性樹脂をより多く強化繊維に含浸することが可能になる。この場合、熱可塑性樹脂は繊維となるものに限定される。
【００４９】
（６）強化繊維を熱可塑性樹脂のフィルムでサンドイッチし、次いで熱可塑性樹脂のガラス転移温度または融点以上の温度で熱可塑性樹脂を溶融し一体化する。該方法によれば、熱可塑性樹脂をより多く強化繊維に含浸することが可能になる。この場合、熱可塑性樹脂はフィルムとなるものに限定される。
【００５０】
次いで、断面が実質的に平行四辺形であり且つ上下の表面が実質的に平面である成形材料を得る手段としては、前記強化繊維への熱可塑性樹脂を含浸する手段の下流側に、断面を実質的に平行四辺形に賦形する手段と上下の表面を実質的に平面とする手段とを講じる。
【００５１】
このような手段としては、熱可塑性樹脂がガラス転移温度未満とならないようにした状態の成形材料を、先ず、少なくとも熱可塑性樹脂のガラス転移温度以上、流動温度未満に温調された第１番目の上下一対の凹凸ローラーに通過させ、少なくともガラス転移温度未満に調整された最終番目の上下一対の凹凸ローラーに通過させることによって達成される。
【００５２】
ガラス転移温度が２００℃を超えるポリイミド樹脂のような高いガラス転移温度を有する熱可塑性樹脂の場合、複数個の上下一対の凹凸ローラーを設け、段階的に温度を低下させ、最終番目の凹凸ローラーが室温付近に調整されるように導入することが好ましい。
【００５３】
前記手段によれば、断面が実質的に平行四辺形であり且つ上下の表面が実質的に平面である成形材料を得ることが可能となる。
【００５４】
成形材料及び製造プロセスの一例
以下に本発明の成形材料の製造プロセスの一例を具体的に述べる。
【００５５】
図１は本発明の製造方法により得られる一実施の形態に係る成形材料を示す。成形材料３０は少なくとも一方向に配向した強化繊維モノフィラメント１２に熱可塑性樹脂１５を含浸したシート状組成物であって、断面が実質的に平行四辺形であり且つ、上下の面の凹凸指数δが５０μｍ以下、好ましくは３０μｍ以下である成形材料である。ここでいうところの凹凸指数とは、図２に示すように成形材料３０の表面３３において、凹凸の最大値から最小値を引いた絶対値である。
【００５６】
図３は本発明の一実施の形態に係る成形材料を製造するためのプロセスを示すものである。
【００５７】
すなわち強化繊維モノフィラメント１２を１０００〜４０００００本束ねた強化繊維束の強化繊維シート１３または強化繊維束を複数本並べてなる強化繊維シート１３（以下強化繊維シートと呼称）を少なくとも粉末状熱可塑性樹脂と分散媒とを含むサスペンジョン液５０が入った浴槽５１にガイドローラー４０を介して導入する。ここで強化繊維シート１３は複数本の互い違いに浴槽５１内に配置されたガイドバー４２、４３、４４、４５、４６を通過する間に、開繊されつつ粉末状熱可塑性樹脂が強化繊維モノフィラメント１２（図１）の間に取り込まれる。
【００５８】
粉末状熱可塑性樹脂が強化繊維モノフィラメント１２の間に取り込まれることを容易にするためには、一般に、粉末状熱可塑性樹脂の平均粒子径が５〜２０μｍ、最大粒子径が１００μｍ未満であることが必要である。粉末状熱可塑性樹脂の粒子径が５μｍ未満であると粒子径が小さすぎて強化繊維モノフィラメント１２の間に取り込まれたものが素抜けし脱落するため量的に樹脂が非常に少なくなり成形材料３０としての性能が発現できない。一方、粉末状熱可塑性樹脂の粒子径が１００μｍ以上であると粒子径が大きすぎるために強化繊維モノフィラメント１２の間に取り込まれる樹脂の量が非常に少なくなり成形材料３０としての性能が発現できないからである。実際に、強化繊維モノフィラメント１２の間に取り込まれる樹脂量は、前述の樹脂の粒子径の他に、サスペンジョン液５０の濃度、分散媒の種類、強化繊維の種類などによって任意に調整される。
【００５９】
尚、強化繊維シート１３には一般的に取り扱い性を改善するためや成形物の性能を発現するために適当な集束剤が数％施されているものもある。このような集束剤の付着した強化繊維シート１３を用いる場合には強化繊維シート１３の開繊性に対してはマイナス要因となり粉末状熱可塑性樹脂の付着を妨げるように作用する場合や集束剤が最終成形品の諸特性に悪影響を及ぼす場合には、サスペンジョン液５０に導入する上流側で溶剤や焼却によって強化繊維シート１３に含まれる集束剤を除去する工程を設けることが好ましい。
【００６０】
強化繊維モノフィラメント１２の間に粉末状熱可塑性樹脂を付着した強化繊維シート１８は粉末状熱可塑性樹脂の融点またはガラス転移温度以上に加熱された加熱炉６５にガイドローラー４１を介して導入され、粉末状熱可塑性樹脂は融けて強化繊維モノフィラメント１２と一体となって成形材料の中間物２０となる。ここで、加熱炉６５には上部スチールベルト６０と下部スチールベルト６１とが一対となったベルトコンベア６３を設け、粉末状熱可塑性樹脂を付着した強化繊維シート１８がベルトコンベア６３を通過するようにすることで粉末状熱可塑性樹脂が強化繊維モノフィラメント１２の間に充分に含浸した状態となり、且つ、表面の平滑性をも付与することになる。
【００６１】
尚、粉末状熱可塑性樹脂を付着した強化繊維シート１８に含まれるサスペンジョン液５０の分散媒を飛散させるためにガイドローラー４１と加熱炉６５との間に乾燥機５５を設けることが好ましい。なぜなら、乾燥機５５を設けないと、加熱炉６５の温度が一般には１５０℃以上となるため分散媒によってはこの温度で突沸し、成形材料の中間物２０にボイドや表面くぼみ等の欠陥が発生する場合があるためである。
【００６２】
次いで、成形材料の中間物２０は、加熱炉６５を通過後、熱可塑性樹脂の温度がガラス転移温度以下にならない様に凸ローラー７０と凹ローラー７１とが一対となったローラーに通過させ成形材料の中間物２０の断面形状を形成する。
【００６３】
加熱炉６５の下流側に設けられた第１番目の一対のローラー７０、７１の出側と第２番目の一対のローラー７２、７３の入り側との距離は出来るだけ短い方が第１番目で形成された断面形状を維持するために好ましい。このためには、凸ローラーと凹ローラーの直径は小さくし、複数本設けることが好ましい。この場合、第２番目の一対のローラーと第３番の一対のローラーの距離も前記第１番目の一対のローラーと第２番目の一対のローラーの距離と同様であり、以後のローラーについても同様である。凸ローラーと凹ローラーの対の数は使用する熱可塑性樹脂の種類や強化繊維の種類やライン速度に依って異なるが、精度の高い断面形状を得るためには少なくとも３組〜５組設けることが望ましい。図３には５組の例として、凸ローラー７０、７２、７４、７６、７８と凹ローラー７１、７３、７５、７７、７９を示している。
【００６４】
このような凸ローラーと凹ローラーの直径は３０〜１００ｍｍ、また、図４に示すように一対のローラー間の距離（互いに隣接するローラー間の距離）７１ａは３５〜１０５ｍｍ程度が好ましい。
【００６５】
凸ローラー７０、７２、７４、７６、７８と凹ローラー７１、７３、７５、７７、７９の温度は、断面形状が実質的な平行四辺形であり且つ上下の表面が実質的に平面である成形材料を得るために非常に重要である。
【００６６】
成形材料の中間物２０は、加熱炉６５の下流側に設けられた第１番目の一対の凹凸ローラー７０、７１に導入されるまでの間に温度が低下するが、成形材料の中間物２０は、加熱炉６５の下流側に設けられた第１番目の一対の凹凸ローラー７０、７１に導入されるまでの間に熱可塑性樹脂の温度がガラス転移温度未満とならないようにし、且つ、少なくとも熱可塑性樹脂のガラス転移温度以上、流動温度未満に温調された第１番目の上下一対の凹凸ローラー７０、７１を通過させ、少なくともガラス転移温度未満に調整された最終番目の上下一対の凹凸ローラー７８、７９を通過させることによって本発明の成形材料３０が得られる。
【００６７】
第１番目の一対の凹凸ローラー７０、７１に導入されるまでの間に成形材料の中間物２０の熱可塑性樹脂の温度がガラス転移温度未満とならないようにすることと第１番目の一対の凹凸ローラー７０、７１の温度が熱可塑性樹脂のガラス転移温度以上で流動温度未満であることとは、第１番目の一対の凹凸ローラー７０、７１での成形材料の変形を容易にするためであり、また、表面平滑性を発現するためである。第１番目の一対の凹凸ローラー７０、７１の温度が熱可塑性樹脂のガラス転移温度未満であると樹脂の変形が困難なため実質的な平行四辺形とはならないばかりか、成形材料の中間物２０は急冷却されることによりその表面に皺が発生する。
【００６８】
一方、第１番目の一対の凹凸ローラー７０、７１の温度が熱可塑性樹脂の流動温度以上となると熱可塑性樹脂が流動するため成形材料が固化しないので形状が定まらない。
【００６９】
最終番目の一対の凹凸ローラー７８、７９の温度がガラス転移温度未満であるのは第１番目以降の一対の凹凸ローラーで形成された成形材料の断面形状を更に決定的な状態にするためである。
【００７０】
前記一対の凹凸ローラーの数は使用する熱可塑性樹脂の種類や強化繊維の種類によって任意に設定することができる。
【００７１】
一対の凹凸ローラーにより成形材料へ負荷する圧力は線圧で０．５〜５ｋｇ／ｃｍ程度であれば断面形状が実質的な平行四辺形であり表面平滑性である成形材料が得られる。
【００７２】
尚、熱可塑性樹脂の種類によっては、第２番目以後の一対の凹凸ローラーの温度を段階的に室温まで下げるような温度設定をとってもよい。
【００７３】
これらの温度制御は図５に示すような凸ローラーと凹ローラーに埋め込まれた温度制御可能なヒーター１０１によって、各ローラー毎に行われる。ヒーター１０１は熱媒のような液体状のものであってもよい。
【００７４】
また、一対の凹凸ローラーによってできる平行四辺形の断面形状は第１番目の一対の凹凸ローラー７０、７１から最終番目の一対の凹凸ローラー７８、７９までの断面形状が最終の成形材料３０の断面形状と同じであってよく、または、少なくとも最終番目の一対の凹凸ローラー７８、７９の断面形状が最終の成形材料３０と同じであり且つ第１番目の一対の凹凸ローラー７０、７１から最終番目の一つ上流側の一対の凹凸ローラー７６、７７の断面形状が最終番目より小さくてよい。
【００７５】
次に、前述のようにして成形材料の中間物２０は複数の一対の凹凸ローラーによって断面形状が実質的に平行四辺形で且つ上下の表面が実質的に平面である最終の成形材料３０となる。成形材料３０はワインダー９０によって巻き取ることもできる。
【００７６】
【実施例】
以下に実施例により具体的に説明するが、本発明はその要旨を超えない限り下記実施例に限定されるものではない。
【００７７】
〔実施例１〕
図３に示すように、強化繊維シート１３として東邦レーヨン（株）製の炭素繊維束ＨＴＡ−１２Ｋ（炭素繊維モノフィラメント１２０００本、引張り強度３９２０ＭＰａ、弾性率２３５、比重１．７７、伸度１．７％、汎用サイズ品）の１本束を用い、炭素繊維束（強化繊維シート１３）は強化繊維ボビン１０に２ｋｇ巻いてあるものを用いた。
【００７８】
マトリックス用樹脂としてはＶｉｃｔｒｅｘ社製ポリエーテルエーテルケトン（以下ＰＥＥＫと呼称：融点３３４℃、ガラス転移温度１４３℃）を機械粉砕により平均粒子径１０μｍ、最大粒子径５０μｍの粉末状熱可塑性樹脂としたものを用いた。炭素繊維束ＨＴＡ−１２Ｋはガイドローラー４０を介してＰＥＥＫ樹脂の入ったパウダーサスペンジョン液５０の入った浴槽５１に導入される。
【００７９】
ここで、パウダーサスペンジョン液５０はＰＥＥＫ粉末をアセトンやアルコール等を含む極性有機溶媒に分散させたもので、ＰＥＥＫ樹脂/極性有機溶媒の濃度は約７〜１０ｇ／リットルの範囲となるように運転中にコントロールした。
【００８０】
浴槽５１には固定式のガイドバー４２〜４６を５本設け、炭素繊維束はガイドバー４２〜４６を交互に通過させ、通過する間に、開繊されつつＰＥＥＫ樹脂が炭素繊維モノフィラメントの間に取り込まれるようにした。尚、炭素繊維束にはエポキシ系の集束剤が付着しているためサスペンジョン浴槽５１に入る前にアセトンで除去する工程を設けた。
【００８１】
前述のようにして、炭素繊維束にＰＥＥＫ樹脂粉末が取り込まれた炭素繊維束（粉末状熱可塑性樹脂を付着した強化繊維シート１８）を得た。該炭素繊維束は次いで１２０℃に設定された乾燥機１８を通過し、ここで極性有機溶媒を除去した。次いで、加熱炉６５に導入した。加熱炉６５に設けられた上下一対のスチールベルトコンベア６３が３８０℃一定に保たれるように設定して炭素繊維束を通過させた。
【００８２】
この時のスチールベルトコンベア６３による圧力は３ｋｇｆ／ｃｍ² とした。加熱炉６５により炭素繊維束に付着したはＰＥＥＫ樹脂は溶融し、炭素繊維モノフィラメントと一体化した成形材料の中間物２０を得た。次いで、該成形材料の中間物２０は、加熱炉６５の下流側に設けられた第１番目の一対のローラー（凸ローラー７０と凹ローラー７１）に導入した。尚、加熱炉６５を出てから第１番目の一対のローラーに入る時点での該成形材料の中間物２０の温度は２２０℃であった。
【００８３】
前記一対の凹凸ローラーは５対設置し該成形材料の中間物２０を通過させた。尚、図４に示すように第１番目の一対のローラー７０、７１の出側と第２番目の一対のローラー７２、７３の入り側との距離７１ａは６０ｍｍとし、図５に示すように一対の凹凸ローラーによってできる断面は成形材料の幅（凹凸ローラーの凹凸部分の幅７１ｂ）となる長方形であり、第１番目のローラーから第５番目のローラーまで、それぞれ、５．５ｍｍ、５．７ｍｍ、５．９ｍｍ、６．０ｍｍ、６．０ｍｍとした。
【００８４】
また、一対の凹凸ローラーの温度は、第１番目のローラーから第５番目のローラーまで、それぞれ、２２０℃、１８０℃、１５０℃、１２０℃、８０℃とした。
【００８５】
一対の凹凸ローラーにより成形材料へ負荷する圧力は線圧で２ｋｇ／ｃｍとした。
【００８６】
このようにして最終の成形材料３０を得た。成形材料３０は最後にワインダー９０に巻き付けられた。得られた成形材料３０は、その断面を顕微鏡で観察した結果ほぼ長方形であり、その幅（Ｗ）が６．０ｍｍ、厚さ（Ｔ）が０．１３０ｍｍの矩形であり、Ｗ／Ｔは４６．２であった。また、硫酸で分解して測定したＰＥＥＫ樹脂含有量は３５％、炭素繊維体積含有率は５８％、ボイド率は０．６％であった。
【００８７】
また、成形材料３０の表面を株式会社キーエンス製のレーザーフォーカス式変位計を用いて計算した凹凸指数δは、３０μｍであり、非常に表面平滑性に優れていた。成形材料３０の巻き最小直径は１５ｍｍで、これより小さくすると炭素繊維の切断による破損が発生した。
【００８８】
はんだごてで成形材料３０の両端部を接合して複数本並べてシート状とし、これを一方向に１６ｐｌｙ金型内に積層し、ホットプレスを用いて温度３９０℃、圧力３ｋｇｆ／ｃｍ² 、保持時間３分間の条件で積層板を製作した。硫酸で分解して測定した積層板のボイド率は０．１％であった。
【００８９】
この積層板について、ＡＳＴＭ Ｄ ３０３９ 及びＡＳＴＭ Ｄ ３８６４に準拠して９０°引張強度試験及び圧縮層間せん断強度試験を実施した。
【００９０】
９０°引張強度及び圧縮層間せん断強度は、各々８５ＭＰａ及び１１２ＭＰａであった。これらの結果を下記表１に示す。
【００９１】
〔実施例２〕
前記実施例１で凹凸ローラーの第１ローラー温度を２００℃とした以外は前記実施例１と同様にして、成形材料３０を得た。
【００９２】
得られた成形材料３０は、その断面を顕微鏡で観察した結果ほぼ長方形であり、その幅（Ｗ）が６．０ｍｍ、厚さ（Ｔ）が０．１３１ｍｍの矩形であり、Ｗ／Ｔは４５．８であった。また、硫酸で分解して測定したＰＥＥＫ樹脂含有量は３５％、炭素繊維体積含有率は５７％、ボイド率は０．９％であった。
【００９３】
また、成形材料３０の表面を株式会社キーエンス製のレーザーフォーカス式変位計を用いて計算した凹凸指数δは、４０μｍであり、表面平滑性に優れていた。
【００９４】
成形材料３０の巻き最小直径は１５ｍｍで、これより小さくすると炭素繊維の切断による破損が発生した。
【００９５】
はんだごてで成形材料３０の両端部を接合して複数本並べてシート状とし、これを一方向に１６ｐｌｙ金型内に積層し、ホットプレスを用いて温度３９０℃、圧力３ｋｇｆ／ｃｍ² 、保持時間３分間の条件で積層板を製作した。硫酸で分解して測定した積層板のボイド率は０．３％であった。
この積層板について、ＡＳＴＭ Ｄ ３０３９ 及びＡＳＴＭ Ｄ ３８６４に準拠して９０°引張強度試験及び圧縮層間せん断強度試験を実施した。
【００９６】
９０°引張強度及び圧縮層間せん断強度は、各々８３ＭＰａ及び１１０ＭＰａであった。これらの結果を下記表１に示す。
【００９７】
〔実施例３〕
前記実施例１で凹凸ローラーの第１ローラー温度を１８０℃とした以外は前記実施例１と同様にして、成形材料３０を得た。
【００９８】
得られた成形材料３０は、その断面を顕微鏡で観察した結果ほぼ長方形であり、その幅（Ｗ）が６．０ｍｍ、厚さ（Ｔ）が０．１３２ｍｍの矩形であり、Ｗ／Ｔは４５．５であった。また、硫酸で分解して測定したＰＥＥＫ樹脂含有量は３５％、炭素繊維体積含有率は５７％、ボイド率は１．１％であった。
また、成形材料３０の表面を株式会社キーエンス製のレーザーフォーカス式変位計を用いて計算した凹凸指数δは、５０μｍであり、表面平滑性に優れていた。
【００９９】
成形材料３０の巻き最小直径は１５ｍｍで、これより小さくすると炭素繊維の切断による破損が発生した。
【０１００】
はんだごてで成形材料３０の両端部を接合して複数本並べてシート状とし、これを一方向に１６ｐｌｙ金型内に積層し、ホットプレスを用いて温度３９０℃、圧力３ｋｇｆ／ｃｍ² 、保持時間３分間の条件で積層板を製作した。硫酸で分解して測定した積層板のボイド率は０．３％であった。
【０１０１】
この積層板について、ＡＳＴＭ Ｄ ３０３９ 及びＡＳＴＭ Ｄ ３８６４に準拠して９０°引張強度試験及び圧縮層間せん断強度試験を実施した。
【０１０２】
９０°引張強度及び圧縮層間せん断強度は、各々８２ＭＰａ及び１０９ＭＰａであった。これらの結果を下記表１に示す。
【０１０３】
〔比較例１〕
前記実施例１で凹凸ローラーの第１番目から第５の温度を１００℃、９０℃、８０℃、７０℃、６０℃とした以外は前記実施例１と同様にして、成形材料３０を得た。
【０１０４】
得られた成形材料３０は、その断面を顕微鏡で観察した結果ほぼ長方形であり、その幅（Ｗ）が５．９ｍｍ、厚さ（Ｔ）が０．１３８ｍｍであり、Ｗ／Ｔは４１．９であった。また、硫酸で分解して測定したＰＥＥＫ樹脂含有量は３５％、炭素繊維体積含有率は５４％、ボイド率は３％であった。
【０１０５】
また、成形材料３０の表面を株式会社キーエンス製のレーザーフォーカス式変位計を用いて計算した凹凸指数δは、７０μｍであり、表面平滑性に劣るものであり、表面に皺も認められた。
【０１０６】
成形材料３０の巻き最小直径は１５ｍｍで、これより小さくすると炭素繊維の切断による破損が発生した。
【０１０７】
はんだごてでプリプレグ両端部を接合して複数本並べてシート状とし、これを一方向に１６ｐｌｙ金型内に積層し、ホットプレスを用いて温度３９０℃、圧力３ｋｇｆ／ｃｍ² 、保持時間３分間の条件で積層板を製作した。硫酸で分解して測定した積層板のボイド率は１．０％であった。
【０１０８】
この積層板について、ＡＳＴＭ Ｄ ３０３９ 及びＡＳＴＭ Ｄ ３８６４に準拠して９０°引張強度試験及び圧縮層間せん断強度試験を実施した。
【０１０９】
９０°引張強度及び圧縮層間せん断強度は、各々７６ＭＰａ及び９１ＭＰａであった。これらの結果を下記表１に示す。
【０１１０】
〔比較例２〕
前記実施例１で凹凸ローラーを取り外し、その代わりにストレートタイプのヒートバー１本を設け、この温度を１００℃とした以外は前記実施例１と同様にして、成形材料を得た。
【０１１１】
得られた成形材料３０は、その断面を顕微鏡で観察した結果、断面中央部に対して両端が薄い扁平状であり、その幅（Ｗ）が７．８ｍｍ、厚さ（Ｔ）が平均で０．１０３ｍｍであり、Ｗ／Ｔは７５．７であった。また、硫酸で分解して測定したＰＥＥＫ樹脂含有量は３５％、炭素繊維体積含有率は５２％、ボイド率は５％であった。
【０１１２】
また、成形材料３０の表面を株式会社キーエンス製のレーザーフォーカス式変位計を用いて計算した凹凸指数δは、１４０μｍであり、表面平滑性に非常に劣るものであり、表面に皺も認められた。
【０１１３】
成形材料３０の巻き最小直径は１５ｍｍで、これより小さくすると炭素繊維の切断による破損が発生した。
【０１１４】
はんだごてでプリプレグ両端部を接合して複数本並べてシート状とし、これを一方向に２０ｐｌｙ金型内に積層し、ホットプレスを用いて温度３９０℃、圧力３ｋｇｆ／ｃｍ² 、保持時間３分間の条件で積層板を製作した。硫酸で分解して測定した積層板のボイド率は１．７％であった。
【０１１５】
この積層板について、ＡＳＴＭ Ｄ ３０３９ 及びＡＳＴＭ Ｄ ３８６４に準拠して９０°引張強度試験及び圧縮層間せん断強度試験を実施した。
【０１１６】
９０°引張強度及び圧縮層間せん断強度は、各々７０ＭＰａ及び８５ＭＰａであった。これらの結果を下記表１に示す。
【０１１７】
【表１】

【０１１８】
【発明の効果】
以上のように本発明によれば、強化繊維に熱可塑性樹脂が高度に含浸され、且つ断面形状が実質的に平行四辺形であり、且つ上下の表面が実質的に平面である連続成形材料を提供することが可能となる。
【０１１９】
従って本発明の製造方法により得られる成形材料によれば、製品の加工温度を与えた状態で比較的短い時間で僅かな圧力を付加するのみで強化繊維が規則正しく配列されたボイドのない最終成形品を得ることが可能となる。
【０１２０】
本発明の製造方法により得られる成形材料によれば、例えばファイバープレースメントのような低コスト加工方法に適用できるようになるとともに、これによって得られた成形物はスポーツ用具、産業用部材あるいは航空機用部材などの各種の用途に広く適用できるようになる。
【図面の簡単な説明】
【図１】 本発明の製造方法により得られる成形材料の構造を示す斜視図である。
【図２】 本発明の製造方法により得られる成形材料の凹凸指数δを示す縦断面図である。
【図３】 本発明の成形材料の連続的な製造プロセスを示す側面図である。
【図４】 本発明の成形材料の断面を平行四辺形に製造するためのプロセスを示す側面図である。
【図５】 本発明の成形材料の断面を平行四辺形に製造するためのプロセスを示す正面図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding material in which a reinforcing fiber sheet oriented in one direction is impregnated with a thermoplastic resin, a molding material having a substantially parallelogram cross-sectional shape and substantially flat upper and lower surfaces, and production thereof Regarding the method.
[0002]
In recent years, for example, a fiber placement method has attracted attention as one of low-cost processing methods for fiber-reinforced resin composite materials. In this method, a composition in which a reinforcing fiber is impregnated with a matrix resin is pressed with a head while being heated so as to have an appropriate tack, and is continuously stuck to the mold surface of a molded body.
[0003]
The present invention relates to a molding material suitable for the fiber placement method and a manufacturing method thereof.
More specifically, the molding material of the present invention is used as a sports equipment, an industrial member or an aircraft member.
[0004]
[Prior art]
Conventionally, a thermoplastic resin is used as a matrix resin, and this matrix resin is impregnated into a bundle of unidirectionally oriented fibers or a narrow tape to form a molding material. The molding material is arranged, heat is applied, and the matrix resin is melted and molded. The method of obtaining an object is known as the fiber placement method. The fiber placement method combines the advantages of automatic lamination and filament winding. That is, it can be laminated in a complicated shape or recess, there is no loss of molding material caused by cutting compared to molding in which sheets are laminated, and compaction can be performed simultaneously.
[0005]
As the tape-shaped molding material used here, for example, the following are applied.
[0006]
French Patent No. 2031719 shows the following. That is, the plurality of fibers are separated from each other in a venturi through which fluid flows. The plurality of separated fibers pass through a feeder having a powdered synthetic resin, and the powdered synthetic resin adheres thereto. The plurality of fibers to which the powdery synthetic resin is adhered then travels through a heated mold, and is solidified by the mold to form a strip-shaped object.
[0007]
Japanese Patent Publication No. 3-58894 shows the following. That is, a plurality of fibers are dipped in a tank containing resin particles, passed therethrough to adhere resin particles, and then the plurality of fibers to which resin particles are attached are heated and melted to obtain 2 Narrow pressure is applied between cylinders cooled by a stream of water to form a mold strip filled with molten resin. The strip is then shrunk by cooling by passing through a temperature-controlled water cooled smoother to give a smooth finish.
[0008]
[Problems to be solved by the invention]
In the fiber placement method, molding materials are lined up without gaps, and the matrix resin is melt-heated and molded. If there is a gap between the tape-shaped molding materials, the fiber strength such as the interlayer strength of the molded product and 90 ° tensile strength This causes a decrease in the adhesion performance at the interface between the resin and the resin.
[0009]
In order to reduce such voids, it is necessary to pressurize from outside during molding to remove the resin flow and bubbles.
[0010]
A molding material obtained by a conventionally known method is not satisfactory in the following points.
[0011]
That is, in the above-mentioned French Patent No. 2031719, there is virtually no method for controlling the distribution of the resin among the plurality of fibers. Therefore, the resin spread between the fibers cannot be uniform, and the method cannot obtain a high fiber content, so that a high strength cannot be obtained when formed into a molded product. Further, in the above-mentioned French patent publication, a plurality of fibers adhered with a powdered synthetic resin are solidified by a heated mold to obtain a band-like material, but simply by passing the heated mold, Even if a strip is obtained, a continuous strip having a predetermined cross-sectional shape with high accuracy cannot be obtained.
[0012]
In Japanese Patent Publication No. 3-58894, when a plurality of fibers pass through a plurality of rollers provided in an aqueous dispersion resin particle tank, the resin particles separate the plurality of fibers from each other and enter between the fibers. Since the amount of the resin can be adjusted by the concentration of the aqueous dispersion resin particle tank, a high fiber content can be obtained, and a product having a relatively high impregnation property can be obtained. However, molding of the molding material is performed by narrowing the pressure between the two upper and lower cooled cylinders. However, in this method, since the cooling is rapidly performed by the cooling cylinder, the molding material contracts and occurs on the surface. Habits occur. In order to prevent this, it has been proposed to pass through a smoother cooled by temperature-adjustable water, but since the smoother has no means for regulating the width direction of the strip, it has a predetermined cross-sectional shape with high accuracy. A continuous strip cannot be obtained. The temperature-adjustable water in the cooling cylinder is estimated to be less than 100 ° C. At this temperature, for example, a heat-resistant polymer material having a heat deformation temperature of 100 ° C. or higher, such as a thermoplastic polyimide resin, may be damaged by shrinkage. Will not be smooth. Therefore, the molded product obtained by this method has an unstable cross-sectional shape and does not necessarily have good surface smoothness.
[0013]
The present invention has been made in view of such problems, and is highly impregnated with a thermoplastic resin between reinforcing fibers, has a substantially parallelogram cross-sectional shape, and has substantially upper and lower surfaces. An object of the present invention is to provide a continuous molding material that is flat and a method for producing the same.
[0014]
[Means for Solving the Problems]
  To solve the above problemsThe present invention includes a means for adhering a thermoplastic resin to a reinforced fiber sheet oriented in one direction, a means for heating and integrating the reinforcing fiber sheet to which the thermoplastic resin is adhered in a heating furnace, And a means for heating and melting the reinforcing fiber sheet to which the thermoplastic resin is adhered in a heating furnace. The reinforcing fiber sheet to which the thermoplastic resin is attached is passed between a pair of upper steel belt and lower steel belt between belt conveyors, the cross section is a parallelogram, and the upper and lower surfaces are planes The means to do is to provide a plurality of upper and lower pairs of concave and convex rollers on the downstream side of the heating furnace, and the temperature of the thermoplastic resin becomes less than the glass transition temperature until it is introduced into the first concave and convex rollers. And pass through the first uneven roller that is adjusted to at least the glass transition temperature of the thermoplastic resin and lower than the flow temperature, and passes through the final uneven roller that is adjusted to at least less than the glass transition temperature. It is a manufacturing method of the molding material characterized by the above-mentioned.
[0015]
  The molding material obtained by the production method of the present invention is:Molding material in which reinforced fiber sheet oriented in one direction is impregnated with thermoplastic resinAndThe cross-sectional shape is substantially a parallelogram, and the upper and lower surface irregularities index δ is δ ≦ 50 μm.The
[0016]
  Of the present inventionObtained by manufacturing methodA preferred embodiment of the molding material is:
The unevenness index δ may be a molding material having δ ≦ 30 μm,
The minimum winding diameter of the molding material may be 15 mm,
The minimum winding diameter of the molding material may be 50 mm,
The ratio of the thickness (Tmm) to the width (Wmm) of the molding material may be 1 ≦ W / T ≦ 10000,
The cross-sectional shape of the molding material may be rectangular,
The volume content of reinforcing fibers in the molding material may be 30 to 70%,
The reinforcing fiber of the molding material may be selected from carbon fiber, metal-coated carbon fiber, aramid fiber, glass fiber, or a combination of two or more types,
The thermoplastic resin of the molding material is polyethylene, polypropylene, polystyrene, ABS, PMMA, polyvinyl alcohol, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyamide, polyacetal, polycarbonate, polybutylene terephthalate, polysulfone, polyethersulfone, polyphenylene sulfide, You may combine single or 2 types or more chosen from the polyamideimide, polyetherimide, polyetheretherketone, and thermoplastic polyimide.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
  Of the present inventionObtained by manufacturing methodThe molding material is composed of reinforcing fibers oriented in one direction and a thermoplastic resin impregnated between the reinforcing fibers.
[0020]
Reinforcing fiber
Examples of the reinforcing fibers include carbon fibers, metal-coated carbon fibers, aramid fibers, and glass fibers.
[0021]
Carbon fibers are obtained by firing polyacrylonitrile, pitch, rayon, etc. by a known method, and are usually subjected to surface treatment or size treatment, but those not subjected to these are also used.
[0022]
The metal-coated carbon fiber is a fiber in which a metal film such as nickel is formed on the surface of the carbon fiber.
[0023]
An aramid fiber is a synthetic fibrous polymer composed of aromatic groups linked through amide bonds, and more than 85% of the amide bonds are directly bonded to two aromatic rings, and more than 50% of the amide groups. May be substituted with an imide group. The aramid fiber includes a meta-aramid fiber mainly composed of a meta-aromatic compound and a para-aramid fiber mainly composed of a para-aromatic compound. As the meta-aramid fiber, a fiber made of polymetaphenylene isophthalamide, such as Nomex (trade name) manufactured by DuPont, Cornex (trade name) manufactured by Teijin Limited, or the like can be used. Further, as the para-aramid fiber, a fiber made of polyparaphenylene isophthalamide, such as Kevlar (trade name) manufactured by DuPont can be used. Further, as a copolymer type para-aramid fiber, Technora (trade name) manufactured by Teijin Limited can be used.
[0024]
In addition, various glass raw materials made of silica sand, alumina, etc. are once formed into marbles called marble, which are then melted and spun and melted to create a flow of molten glass from a melting furnace or melting furnace. These fibers are obtained by a direct melt method in which spinning is performed directly from a number of spinning furnaces provided along the flow, and are fibers called E glass, S glass, A glass, and T glass.
[0025]
These fibers can be used alone or in combination of two or more.
[0026]
Thermoplastic resin
As the thermoplastic resin, for example, general-purpose resins such as polyethylene, polypropylene, polystyrene, ABS, PMMA, polyvinyl alcohol, polyethylene terephthalate, polyvinyl chloride, and polyvinylidene chloride may be used. Polyamide, polyacetal, polycarbonate, poly General engineering plastics such as butylene terephthalate may be used, and special engineering plastics such as polysulfone, polyethersulfone, polyphenylene sulfide, polyamideimide, polyetherimide, polyetheretherketone, and thermoplastic polyimide are used. It's okay.
[0027]
These thermoplastic resins can be used alone or in combination of two or more.
[0028]
Resin composition
The proportion of the reinforcing fiber and the thermoplastic resin contained in the molding material is preferably 30 to 70% in terms of the volume content of the reinforcing fiber. This is because if it is less than 30%, the effect of reinforcing the molded product is poor, and if it exceeds 70%, the thermoplastic resin is insufficient in quantity, resulting in a decrease in the interfacial strength between the reinforcing fiber and the thermoplastic resin.
[0029]
The molding material may contain additives such as a fluidity modifier, a flame retardant, and a colorant depending on the purpose of use. However, the use of additives may lead to a decrease in chemical and mechanical performance that the molding material basically possesses. Therefore, when additives are used, the purpose of using the molding material is not hindered. You may use for.
[0030]
  Surface of molding material
  Of the present inventionObtained by manufacturing methodOne of the greatest characteristics of the molding material is that the upper and lower surfaces of the molding material are substantially flat. That is, the unevenness index δ on the upper and lower surfaces of the molding material is represented by the following formula.
[0031]
[Expression 4]

[0032]
More preferably,
[0033]
[Equation 5]

[0034]
It is.
[0035]
Here, δ is defined as an absolute value obtained by subtracting the minimum height from the maximum height on an arbitrary surface of the molding material.
[0036]
If the concavo-convex index δ exceeds 50 μm, not only will there be local thickness unevenness when many molding materials are laminated, but voids formed by the concavo-convex portions may remain in the final product and become defects. is there.
[0037]
Such unevenness index δ can be measured by the following means. For example, an apparatus using a semiconductor laser as a light source in a laser focus displacement meter manufactured by Keyence Corporation may be used. According to this apparatus, it is possible to measure a very small spot having a diameter of 2 μm with a resolution of 0.1 μm.
[0038]
  Cross section of molding material
  Of the present inventionObtained by manufacturing methodOne of the other characteristics of the molding material is that the cross-sectional shape of the molding material is substantially a parallelogram. That is, the ratio of the thickness (Tmm) to the width (Wmm) of the molding material is in a range represented by the following formula.
[0039]
[Formula 6]

[0040]
When W / T is less than 1, the thickness of the molding material increases, and internal defects such as meandering and voids of fibers are likely to occur inside the molding material, and heat is easily applied when processing the molding material. Therefore, the productivity of the final product is lowered, which is not preferable. On the other hand, when W / T exceeds 10,000, the thickness of the molding material becomes small, and it becomes difficult to produce a molding material having no openings in the width direction.
[0041]
Here, as the parallelogram, a rectangle is preferable from the viewpoint of production and ease of leveling up, but a parallelogram other than a rectangle may be used.
[0042]
Winding diameter of molding material
When the molding material is wound, the minimum winding diameter is desirably 50 mm or more, and more desirably 15 mm or more. When the minimum winding diameter is less than 15 mm, the molding material is damaged by cutting or bending the reinforcing fibers. Therefore, there is no problem as long as the packing form of the molding material is not less than the minimum diameter.
[0043]
Manufacturing method of molding material
The molding material can be manufactured by the following means. For example, first, the following means can be listed as means for impregnating the reinforcing fiber with the thermoplastic resin.
[0044]
(1) The reinforcing fiber is passed through the suspension liquid of the thermoplastic resin powder, the thermoplastic resin is adhered to the reinforcing fiber, and then the thermoplastic resin is melted at a temperature equal to or higher than the glass transition temperature or the melting point of the thermoplastic resin. Integrate. According to this method, it becomes possible to more completely impregnate the reinforcing fiber with the thermoplastic resin. In this case, the average particle size of the thermoplastic resin powder is preferably about 5 to 20 μm, and the thermoplastic resin is limited to a powder form.
[0045]
(2) Passing the reinforcing fiber through a fluidized bed of thermoplastic resin powder, and optionally charging the thermoplastic resin powder to adhere the thermoplastic resin to the reinforcing fiber, and then the glass transition temperature of the thermoplastic resin or The thermoplastic resin is melted and integrated at a temperature equal to or higher than the melting point. According to this method, it becomes possible to more completely impregnate the reinforcing fiber with the thermoplastic resin. In this case, the average particle size of the thermoplastic resin powder is preferably about 5 to 20 μm, and the thermoplastic resin is limited to a powder form.
[0046]
(3) The reinforcing fiber is passed through the thermoplastic resin solution to adhere the thermoplastic resin to the reinforcing fiber, and then the solvent of the thermoplastic resin is removed. According to this method, it becomes possible to more completely impregnate the reinforcing fiber with the thermoplastic resin. In this case, the thermoplastic resin is limited to those that dissolve in the solvent.
[0047]
(4) The molten thermoplastic resin is injected into the reinforcing fiber with an extruder or the like and integrated. According to this method, it becomes possible to impregnate the reinforcing fibers with more thermoplastic resin. In this case, since the thermoplastic resin tends to be in a state where it is coated on the surface of the reinforcing fiber, it is preferable to provide a resin impregnation step.
[0048]
(5) The reinforcing fiber is blended with the fiber of the thermoplastic resin, and then the thermoplastic resin is melted and integrated at a temperature equal to or higher than the glass transition temperature or the melting point of the thermoplastic resin. According to this method, it becomes possible to impregnate the reinforcing fibers with more thermoplastic resin. In this case, the thermoplastic resin is limited to those that become fibers.
[0049]
(6) The reinforcing fibers are sandwiched with a thermoplastic resin film, and then the thermoplastic resin is melted and integrated at a temperature equal to or higher than the glass transition temperature or the melting point of the thermoplastic resin. According to this method, it becomes possible to impregnate the reinforcing fibers with more thermoplastic resin. In this case, the thermoplastic resin is limited to a film.
[0050]
Next, as a means for obtaining a molding material whose cross section is substantially a parallelogram and whose upper and lower surfaces are substantially flat, the cross section is formed on the downstream side of the means for impregnating the reinforcing fiber with the thermoplastic resin. Means for forming a substantially parallelogram and means for making the upper and lower surfaces substantially planar are provided.
[0051]
As such means, the molding material in a state in which the thermoplastic resin does not become less than the glass transition temperature, first, at least the glass transition temperature of the thermoplastic resin, the first temperature is adjusted to be less than the flow temperature. This is achieved by passing through a pair of upper and lower concave and convex rollers and passing through a pair of upper and lower concave and convex rollers adjusted at least below the glass transition temperature.
[0052]
In the case of a thermoplastic resin having a high glass transition temperature such as a polyimide resin having a glass transition temperature exceeding 200 ° C., a plurality of upper and lower pairs of concave and convex rollers are provided, and the temperature is lowered step by step. It is preferable to introduce so as to be adjusted to around room temperature.
[0053]
According to the above means, it is possible to obtain a molding material whose cross section is substantially a parallelogram and whose upper and lower surfaces are substantially flat.
[0054]
  Examples of molding materials and manufacturing processes
  The molding material of the present invention is shown belowFeeAn example of the manufacturing process will be specifically described.
[0055]
  FIG. 1 illustrates the present invention.Obtained by manufacturing methodThe molding material which concerns on one embodiment is shown. The molding material 30 is a sheet-like composition in which the reinforcing fiber monofilament 12 oriented in at least one direction is impregnated with the thermoplastic resin 15, has a substantially parallelogram in cross section, and has an uneven index δ on the upper and lower surfaces. The molding material is 50 μm or less, preferably 30 μm or less. As used herein, the unevenness index is an absolute value obtained by subtracting the minimum value from the maximum value of the unevenness on the surface 33 of the molding material 30 as shown in FIG.
[0056]
FIG. 3 shows a process for producing a molding material according to an embodiment of the present invention.
[0057]
That is, a reinforcing fiber sheet 13 of reinforcing fiber bundles in which 1000 to 400,000 reinforcing fiber monofilaments 12 are bundled or a reinforcing fiber sheet 13 (hereinafter referred to as a reinforcing fiber sheet) formed by arranging a plurality of reinforcing fiber bundles is dispersed in at least a powdered thermoplastic resin. It introduce | transduces via the guide roller 40 into the bathtub 51 containing the suspension liquid 50 containing a medium. Here, while the reinforcing fiber sheet 13 passes through the guide bars 42, 43, 44, 45, 46 arranged alternately in the bathtub 51, the powdered thermoplastic resin is reinforced fiber monofilament 12 while being opened. Captured during (FIG. 1).
[0058]
In order to facilitate the incorporation of the powdered thermoplastic resin between the reinforcing fiber monofilaments 12, the average particle size of the powdered thermoplastic resin is generally 5 to 20 μm and the maximum particle size is less than 100 μm. is necessary. If the particle size of the powdered thermoplastic resin is less than 5 μm, the particle size is too small, and what is taken in between the reinforcing fiber monofilaments 12 comes off and falls off. The performance as can not be expressed. On the other hand, if the particle size of the powdered thermoplastic resin is 100 μm or more, the amount of resin taken in between the reinforcing fiber monofilaments 12 is so small that the performance as the molding material 30 cannot be exhibited. It is. Actually, the amount of resin taken in between the reinforcing fiber monofilaments 12 is arbitrarily adjusted depending on the concentration of the suspension liquid 50, the type of dispersion medium, the type of reinforcing fiber, etc. in addition to the particle diameter of the resin.
[0059]
In some cases, the reinforcing fiber sheet 13 is generally provided with several percent of a suitable sizing agent in order to improve the handleability and to develop the performance of the molded product. When the reinforcing fiber sheet 13 to which such a sizing agent is attached is used, it acts as a negative factor on the openability of the reinforcing fiber sheet 13 and acts to prevent the adhesion of the powdered thermoplastic resin. When adversely affecting various properties of the final molded product, it is preferable to provide a step of removing the sizing agent contained in the reinforcing fiber sheet 13 by solvent or incineration on the upstream side introduced into the suspension liquid 50.
[0060]
The reinforcing fiber sheet 18 having a powdered thermoplastic resin adhered between the reinforcing fiber monofilaments 12 is introduced into a heating furnace 65 heated to a temperature equal to or higher than the melting point or glass transition temperature of the powdered thermoplastic resin via a guide roller 41, and powdered. The thermoplastic resin melts together with the reinforcing fiber monofilament 12 to become an intermediate 20 of the molding material. Here, the heating furnace 65 is provided with a belt conveyor 63 in which an upper steel belt 60 and a lower steel belt 61 are paired so that the reinforcing fiber sheet 18 to which the powdered thermoplastic resin is adhered passes through the belt conveyor 63. By doing so, the powdered thermoplastic resin is sufficiently impregnated between the reinforcing fiber monofilaments 12, and the surface smoothness is also imparted.
[0061]
In addition, it is preferable to provide the dryer 55 between the guide roller 41 and the heating furnace 65 in order to disperse the dispersion medium of the suspension liquid 50 contained in the reinforcing fiber sheet 18 to which the powdered thermoplastic resin is adhered. This is because if the dryer 55 is not provided, the temperature of the heating furnace 65 is generally 150 ° C. or higher, and depending on the dispersion medium, bumping occurs at this temperature, and defects such as voids and surface depressions occur in the intermediate 20 of the molding material. It is because there is a case to do.
[0062]
Next, after passing through the heating furnace 65, the intermediate 20 of the molding material is passed through a roller in which the convex roller 70 and the concave roller 71 are paired so that the temperature of the thermoplastic resin does not become the glass transition temperature or lower. The cross-sectional shape of the intermediate 20 is formed.
[0063]
The distance between the exit side of the first pair of rollers 70 and 71 provided on the downstream side of the heating furnace 65 and the entrance side of the second pair of rollers 72 and 73 is as short as possible. This is preferable for maintaining the formed cross-sectional shape. For this purpose, it is preferable to reduce the diameter of the convex roller and the concave roller and to provide a plurality of them. In this case, the distance between the second pair of rollers and the third pair of rollers is the same as the distance between the first pair of rollers and the second pair of rollers, and the same applies to the subsequent rollers. It is. The number of pairs of convex rollers and concave rollers varies depending on the type of thermoplastic resin used, the type of reinforcing fibers, and the line speed, but at least 3 to 5 sets should be provided to obtain a highly accurate cross-sectional shape. desirable. In FIG. 3, convex rollers 70, 72, 74, 76, 78 and concave rollers 71, 73, 75, 77, 79 are shown as five examples.
[0064]
The diameter of the convex roller and the concave roller is preferably 30 to 100 mm, and the distance 71a between the pair of rollers (distance between adjacent rollers) 71a is preferably about 35 to 105 mm as shown in FIG.
[0065]
The temperature of the convex rollers 70, 72, 74, 76, 78 and the concave rollers 71, 73, 75, 77, 79 is a molding whose cross-sectional shape is a substantially parallelogram and whose upper and lower surfaces are substantially flat. Very important to get the material.
[0066]
The temperature of the intermediate 20 of the molding material decreases until it is introduced into the first pair of concave and convex rollers 70 and 71 provided on the downstream side of the heating furnace 65, but the intermediate 20 of the molding material The temperature of the thermoplastic resin does not become lower than the glass transition temperature until it is introduced into the first pair of concave and convex rollers 70 and 71 provided on the downstream side of the heating furnace 65, and at least the thermoplasticity The first pair of upper and lower concavo-convex rollers 70, 71, which are adjusted to a temperature equal to or higher than the glass transition temperature of the resin and lower than the flow temperature, are passed through the first pair of concavo-convex rollers 78, 71. By passing 79, the molding material 30 of the present invention is obtained.
[0067]
The temperature of the thermoplastic resin of the molding material intermediate 20 is not lower than the glass transition temperature before being introduced into the first pair of uneven rollers 70 and 71, and the first pair of unevenness. That the temperature of the rollers 70 and 71 is equal to or higher than the glass transition temperature of the thermoplastic resin and lower than the flow temperature is to facilitate the deformation of the molding material in the first pair of concave and convex rollers 70 and 71, Moreover, it is for expressing surface smoothness. If the temperature of the first pair of concavo-convex rollers 70 and 71 is lower than the glass transition temperature of the thermoplastic resin, it is difficult to deform the resin, so that it does not become a substantially parallelogram, and the intermediate 20 of the molding material. As a result of rapid cooling, wrinkles are generated on the surface.
[0068]
On the other hand, when the temperature of the first pair of concavo-convex rollers 70 and 71 is equal to or higher than the flow temperature of the thermoplastic resin, the shape of the molding material is not solidified because the thermoplastic resin flows and the molding material is not solidified.
[0069]
The reason why the temperature of the final pair of uneven rollers 78 and 79 is lower than the glass transition temperature is to make the cross-sectional shape of the molding material formed by the first and subsequent pairs of uneven rollers more critical. .
[0070]
The number of the pair of concavo-convex rollers can be arbitrarily set according to the type of thermoplastic resin used and the type of reinforcing fiber.
[0071]
If the pressure applied to the molding material by the pair of concavo-convex rollers is a linear pressure of about 0.5 to 5 kg / cm, a molding material having a substantially parallelogram cross-sectional shape and surface smoothness can be obtained.
[0072]
Depending on the type of the thermoplastic resin, the temperature setting may be made so that the temperature of the second and subsequent pairs of concave and convex rollers is gradually lowered to room temperature.
[0073]
These temperature controls are performed for each roller by a temperature-controllable heater 101 embedded in a convex roller and a concave roller as shown in FIG. The heater 101 may be in a liquid form such as a heat medium.
[0074]
Further, the cross-sectional shape of the parallelogram formed by the pair of concave and convex rollers is the cross-sectional shape from the first pair of concave and convex rollers 70 and 71 to the final pair of concave and convex rollers 78 and 79, and the sectional shape of the final molding material 30. Or the cross-sectional shape of at least the last pair of concavo-convex rollers 78 and 79 is the same as that of the final molding material 30 and the first pair of concavo-convex rollers 70 and 71 is the final first one. The cross-sectional shape of the pair of uneven rollers 76 and 77 on the upstream side may be smaller than the final one.
[0075]
Next, as described above, the intermediate 20 of the molding material becomes the final molding material 30 having a substantially parallelogram-shaped cross-section and a substantially flat upper and lower surface by a plurality of pairs of concave and convex rollers. . The molding material 30 can also be wound up by a winder 90.
[0076]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded.
[0077]
[Example 1]
As shown in FIG. 3, carbon fiber bundle HTA-12K (12,000 carbon fiber monofilaments, tensile strength 3920 MPa, elastic modulus 235, specific gravity 1.77, elongation 1.7) manufactured by Toho Rayon Co., Ltd. as reinforcing fiber sheet 13. %, A general-purpose size product), and a carbon fiber bundle (reinforcing fiber sheet 13) having 2 kg wound around the reinforcing fiber bobbin 10 was used.
[0078]
As a matrix resin, a polyether ether ketone (hereinafter referred to as PEEK: melting point 334 ° C., glass transition temperature 143 ° C.) manufactured by Victrex was mechanically pulverized into a powdery thermoplastic resin having an average particle size of 10 μm and a maximum particle size of 50 μm Was used. The carbon fiber bundle HTA-12K is introduced through a guide roller 40 into a bathtub 51 containing a powder suspension liquid 50 containing PEEK resin.
[0079]
Here, the powder suspension liquid 50 is obtained by dispersing PEEK powder in a polar organic solvent containing acetone, alcohol or the like, and is operating so that the concentration of the PEEK resin / polar organic solvent is in the range of about 7 to 10 g / liter. Controlled.
[0080]
The bathtub 51 is provided with five fixed guide bars 42 to 46, and the carbon fiber bundle is alternately passed through the guide bars 42 to 46, and while passing, the PEEK resin is opened between the carbon fiber monofilaments while being opened. It was made to be taken in. In addition, since the epoxy-type sizing agent adhered to the carbon fiber bundle, a step of removing with acetone before entering the suspension bath 51 was provided.
[0081]
As described above, a carbon fiber bundle (reinforcing fiber sheet 18 with a powdery thermoplastic resin attached) in which PEEK resin powder was incorporated into the carbon fiber bundle was obtained. The carbon fiber bundle then passed through a dryer 18 set at 120 ° C. where the polar organic solvent was removed. Next, it was introduced into the heating furnace 65. A pair of upper and lower steel belt conveyors 63 provided in the heating furnace 65 was set to be kept at 380 ° C., and the carbon fiber bundle was passed.
[0082]
The pressure by the steel belt conveyor 63 at this time is 3 kgf / cm.²It was. The PEEK resin adhered to the carbon fiber bundle by the heating furnace 65 was melted to obtain an intermediate 20 of the molding material integrated with the carbon fiber monofilament. Subsequently, the intermediate 20 of the molding material was introduced into a first pair of rollers (the convex roller 70 and the concave roller 71) provided on the downstream side of the heating furnace 65. The temperature of the intermediate 20 of the molding material at the time of entering the first pair of rollers after leaving the heating furnace 65 was 220 ° C.
[0083]
Five pairs of the pair of concavo-convex rollers were installed, and the intermediate 20 of the molding material was passed therethrough. As shown in FIG. 4, the distance 71a between the exit side of the first pair of rollers 70 and 71 and the entry side of the second pair of rollers 72 and 73 is set to 60 mm, and the pair as shown in FIG. The cross section formed by the concavo-convex roller is a rectangle that becomes the width of the molding material (the width of the concavo-convex portion of the concavo-convex roller 71b), and the first to fifth rollers are 5.5 mm, 5.7 mm, It was set to 5.9 mm, 6.0 mm, and 6.0 mm.
[0084]
Moreover, the temperature of a pair of uneven | corrugated roller was 220 degreeC, 180 degreeC, 150 degreeC, 120 degreeC, and 80 degreeC from the 1st roller to the 5th roller, respectively.
[0085]
The pressure applied to the molding material by the pair of concave and convex rollers was 2 kg / cm as linear pressure.
[0086]
In this way, the final molding material 30 was obtained. The molding material 30 was finally wound around the winder 90. As a result of observing the cross section with a microscope, the obtained molding material 30 is almost rectangular, its width (W) is 6.0 mm, thickness (T) is 0.130 mm, and W / T is 46. .2. The PEEK resin content measured by decomposition with sulfuric acid was 35%, the carbon fiber volume content was 58%, and the void ratio was 0.6%.
[0087]
Further, the unevenness index δ calculated on the surface of the molding material 30 using a laser focus displacement meter manufactured by Keyence Corporation was 30 μm, and the surface smoothness was extremely excellent. The minimum winding diameter of the molding material 30 was 15 mm, and if it was smaller than this, the carbon fiber was broken by cutting.
[0088]
A plurality of the molding materials 30 are joined to each other with a soldering iron to form a sheet, which is laminated in a 16 ply mold in one direction, and a temperature of 390 ° C. and a pressure of 3 kgf / cm using a hot press.²A laminate was produced under the condition of holding time of 3 minutes. The void ratio of the laminate measured by decomposing with sulfuric acid was 0.1%.
[0089]
This laminate was subjected to a 90 ° tensile strength test and a compression interlayer shear strength test in accordance with ASTM D 3039 and ASTM D 3864.
[0090]
The 90 ° tensile strength and compression interlayer shear strength were 85 MPa and 112 MPa, respectively. These results are shown in Table 1 below.
[0091]
[Example 2]
A molding material 30 was obtained in the same manner as in Example 1 except that the first roller temperature of the uneven roller in Example 1 was set to 200 ° C.
[0092]
As a result of observing the cross section with a microscope, the obtained molding material 30 is almost rectangular, its width (W) is 6.0 mm, thickness (T) is 0.131 mm, and W / T is 45. .8. The PEEK resin content measured by decomposition with sulfuric acid was 35%, the carbon fiber volume content was 57%, and the void ratio was 0.9%.
[0093]
Further, the unevenness index δ calculated on the surface of the molding material 30 using a laser focus displacement meter manufactured by Keyence Corporation was 40 μm, and the surface smoothness was excellent.
[0094]
The minimum winding diameter of the molding material 30 was 15 mm, and if it was smaller than this, the carbon fiber was broken by cutting.
[0095]
A plurality of the molding materials 30 are joined to each other with a soldering iron to form a sheet, which is laminated in a 16 ply mold in one direction, and a temperature of 390 ° C. and a pressure of 3 kgf / cm using a hot press.²A laminate was produced under the condition of holding time of 3 minutes. The void ratio of the laminate measured by decomposing with sulfuric acid was 0.3%.
This laminate was subjected to a 90 ° tensile strength test and a compression interlayer shear strength test in accordance with ASTM D 3039 and ASTM D 3864.
[0096]
The 90 ° tensile strength and compression interlayer shear strength were 83 MPa and 110 MPa, respectively. These results are shown in Table 1 below.
[0097]
Example 3
A molding material 30 was obtained in the same manner as in Example 1 except that the first roller temperature of the concavo-convex roller was 180 ° C. in Example 1.
[0098]
As a result of observing the cross section with a microscope, the obtained molding material 30 is almost rectangular, its width (W) is 6.0 mm, thickness (T) is 0.132 mm, and W / T is 45. .5. The PEEK resin content measured by decomposition with sulfuric acid was 35%, the carbon fiber volume content was 57%, and the void ratio was 1.1%.
Further, the unevenness index δ calculated on the surface of the molding material 30 using a laser focus displacement meter manufactured by Keyence Corporation was 50 μm, and the surface smoothness was excellent.
[0099]
The minimum winding diameter of the molding material 30 was 15 mm, and if it was smaller than this, the carbon fiber was broken by cutting.
[0100]
A plurality of the molding materials 30 are joined to each other with a soldering iron to form a sheet, which is laminated in a 16 ply mold in one direction, and a temperature of 390 ° C. and a pressure of 3 kgf / cm using a hot press.²A laminate was produced under the condition of holding time of 3 minutes. The void ratio of the laminate measured by decomposing with sulfuric acid was 0.3%.
[0101]
This laminate was subjected to a 90 ° tensile strength test and a compression interlayer shear strength test in accordance with ASTM D 3039 and ASTM D 3864.
[0102]
The 90 ° tensile strength and compression interlayer shear strength were 82 MPa and 109 MPa, respectively. These results are shown in Table 1 below.
[0103]
[Comparative Example 1]
A molding material 30 was obtained in the same manner as in Example 1 except that the first to fifth temperatures of the uneven roller in Example 1 were 100 ° C, 90 ° C, 80 ° C, 70 ° C, and 60 ° C. .
[0104]
As a result of observing the cross section with a microscope, the obtained molding material 30 is substantially rectangular, its width (W) is 5.9 mm, thickness (T) is 0.138 mm, and W / T is 41.9. Met. The PEEK resin content measured by decomposition with sulfuric acid was 35%, the carbon fiber volume content was 54%, and the void ratio was 3%.
[0105]
Further, the unevenness index δ calculated from the surface of the molding material 30 using a laser focus displacement meter manufactured by Keyence Corporation was 70 μm, which was inferior to the surface smoothness, and wrinkles were observed on the surface.
[0106]
The minimum winding diameter of the molding material 30 was 15 mm, and if it was smaller than this, the carbon fiber was broken by cutting.
[0107]
A plurality of prepreg ends are joined together with a soldering iron to form a sheet, which is laminated in a 16 ply mold in one direction, and a hot press is used at a temperature of 390 ° C. and a pressure of 3 kgf / cm.²A laminate was produced under the condition of holding time of 3 minutes. The void ratio of the laminate measured by decomposing with sulfuric acid was 1.0%.
[0108]
This laminate was subjected to a 90 ° tensile strength test and a compression interlayer shear strength test in accordance with ASTM D 3039 and ASTM D 3864.
[0109]
The 90 ° tensile strength and compression interlayer shear strength were 76 MPa and 91 MPa, respectively. These results are shown in Table 1 below.
[0110]
[Comparative Example 2]
A molding material was obtained in the same manner as in Example 1 except that the concavo-convex roller was removed in Example 1 and a straight type heat bar was provided instead, and this temperature was set to 100 ° C.
[0111]
As a result of observing the cross section with a microscope, the obtained molding material 30 has a flat shape with thin ends at the center of the cross section, its width (W) is 7.8 mm, and its thickness (T) is 0 on average. .103 mm and W / T was 75.7. The PEEK resin content measured by decomposition with sulfuric acid was 35%, the carbon fiber volume content was 52%, and the void ratio was 5%.
[0112]
The unevenness index δ calculated from the surface of the molding material 30 by using a laser focus displacement meter manufactured by Keyence Corporation was 140 μm, which was very inferior in surface smoothness, and wrinkles were observed on the surface. .
[0113]
The minimum winding diameter of the molding material 30 was 15 mm, and if it was smaller than this, the carbon fiber was broken by cutting.
[0114]
A plurality of prepreg ends are joined together with a soldering iron to form a sheet, which is laminated in a 20 ply mold in one direction, and temperature is 390 ° C., pressure 3 kgf / cm using a hot press.²A laminate was produced under the condition of holding time of 3 minutes. The void ratio of the laminate measured by decomposing with sulfuric acid was 1.7%.
[0115]
This laminate was subjected to a 90 ° tensile strength test and a compression interlayer shear strength test in accordance with ASTM D 3039 and ASTM D 3864.
[0116]
The 90 ° tensile strength and compression interlayer shear strength were 70 MPa and 85 MPa, respectively. These results are shown in Table 1 below.
[0117]
[Table 1]

[0118]
【The invention's effect】
As described above, according to the present invention, the continuous molding material in which the reinforcing fiber is highly impregnated with the thermoplastic resin, the cross-sectional shape is substantially a parallelogram, and the upper and lower surfaces are substantially flat. It becomes possible to provide.
[0119]
  Therefore, the present inventionObtained by manufacturing methodAccording to the molding material, it is possible to obtain a final molded product having no voids in which reinforcing fibers are regularly arranged only by applying a slight pressure in a relatively short time with the processing temperature of the product applied.
[0120]
  Of the present inventionObtained by manufacturing methodAccording to the molding material, for example, it can be applied to a low-cost processing method such as fiber placement, and the molded product obtained thereby can be widely used in various applications such as sports equipment, industrial members or aircraft members. Applicable.
[Brief description of the drawings]
FIG. 1 of the present inventionObtained by manufacturing methodIt is a perspective view which shows the structure of a molding material.
FIG. 2 of the present inventionObtained by manufacturing methodIt is a longitudinal cross-sectional view showing the unevenness index δ of the molding material.
FIG. 3 shows the molding material of the present invention.Continuous manufacturing processFIG.
FIG. 4 is a side view showing a process for manufacturing a cross-section of the molding material of the present invention into a parallelogram.
FIG. 5 is a front view showing a process for producing a cross-section of the molding material of the present invention into a parallelogram.

Claims (1)

Means for adhering the thermoplastic resin to the reinforcing fiber sheet oriented in one direction; means for heating and integrating the reinforcing fiber sheet to which the thermoplastic resin adheres in a heating furnace; A method for producing a molding material using a means for flattening the surface,
The means for heating and melting and reinforcing the reinforcing fiber sheet to which the thermoplastic resin is adhered in a heating furnace includes a pair of upper steel belt and lower steel belt in the reinforcing fiber sheet to which the thermoplastic resin is adhered. Is a means of passing between belt conveyors,
The means for making the cross-section a parallelogram and making the upper and lower surfaces flat is provided with a plurality of upper and lower pairs of concave and convex rollers on the downstream side of the heating furnace, and before being introduced into the first concave and convex rollers, a thermoplastic resin The temperature of the glass is not lower than the glass transition temperature, and is passed through the first concavo-convex roller that is temperature-controlled at least above the glass transition temperature of the thermoplastic resin and lower than the flow temperature, and is adjusted to at least lower than the glass transition temperature. A method for producing a molding material, characterized in that it is a means for passing the final uneven roller.

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