JP2004149979A - Carbon fiber strand - Google Patents
Carbon fiber strand Download PDFInfo
- Publication number
- JP2004149979A JP2004149979A JP2002319004A JP2002319004A JP2004149979A JP 2004149979 A JP2004149979 A JP 2004149979A JP 2002319004 A JP2002319004 A JP 2002319004A JP 2002319004 A JP2002319004 A JP 2002319004A JP 2004149979 A JP2004149979 A JP 2004149979A
- Authority
- JP
- Japan
- Prior art keywords
- carbon fiber
- tan
- fiber strand
- sizing agent
- resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229920000049 Carbon (fiber) Polymers 0.000 title claims abstract description 103
- 239000004917 carbon fiber Substances 0.000 title claims abstract description 103
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 88
- 238000004513 sizing Methods 0.000 claims abstract description 78
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 46
- 239000000203 mixture Substances 0.000 claims abstract description 44
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 38
- 239000003822 epoxy resin Substances 0.000 claims abstract description 33
- 239000000835 fiber Substances 0.000 claims abstract description 9
- 238000005259 measurement Methods 0.000 claims description 10
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 claims description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 8
- 229910052760 oxygen Inorganic materials 0.000 claims description 8
- 239000001301 oxygen Substances 0.000 claims description 8
- 229920001400 block copolymer Polymers 0.000 claims description 5
- 229920005989 resin Polymers 0.000 abstract description 32
- 239000011347 resin Substances 0.000 abstract description 32
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract 1
- 229910052799 carbon Inorganic materials 0.000 abstract 1
- 238000000034 method Methods 0.000 description 17
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 16
- 239000011159 matrix material Substances 0.000 description 16
- 239000002131 composite material Substances 0.000 description 13
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 10
- 239000000047 product Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- 239000004593 Epoxy Substances 0.000 description 7
- 238000001035 drying Methods 0.000 description 7
- 239000011342 resin composition Substances 0.000 description 7
- 238000004381 surface treatment Methods 0.000 description 7
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 6
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 description 6
- -1 acrylic ester Chemical class 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 230000000704 physical effect Effects 0.000 description 6
- 239000004918 carbon fiber reinforced polymer Substances 0.000 description 5
- 239000000839 emulsion Substances 0.000 description 5
- 238000007654 immersion Methods 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 229920003986 novolac Polymers 0.000 description 5
- 229920001187 thermosetting polymer Polymers 0.000 description 5
- 238000011282 treatment Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- 239000000805 composite resin Substances 0.000 description 4
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229920002239 polyacrylonitrile Polymers 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 239000000654 additive Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000003995 emulsifying agent Substances 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 229920001567 vinyl ester resin Polymers 0.000 description 3
- 125000004189 3,4-dichlorophenyl group Chemical group [H]C1=C([H])C(Cl)=C(Cl)C([H])=C1* 0.000 description 2
- XMTQQYYKAHVGBJ-UHFFFAOYSA-N 3-(3,4-DICHLOROPHENYL)-1,1-DIMETHYLUREA Chemical compound CN(C)C(=O)NC1=CC=C(Cl)C(Cl)=C1 XMTQQYYKAHVGBJ-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 239000004412 Bulk moulding compound Substances 0.000 description 2
- OWYWGLHRNBIFJP-UHFFFAOYSA-N Ipazine Chemical compound CCN(CC)C1=NC(Cl)=NC(NC(C)C)=N1 OWYWGLHRNBIFJP-UHFFFAOYSA-N 0.000 description 2
- MGJKQDOBUOMPEZ-UHFFFAOYSA-N N,N'-dimethylurea Chemical compound CNC(=O)NC MGJKQDOBUOMPEZ-UHFFFAOYSA-N 0.000 description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 2
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 2
- 239000003677 Sheet moulding compound Substances 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 125000001931 aliphatic group Chemical group 0.000 description 2
- PXKLMJQFEQBVLD-UHFFFAOYSA-N bisphenol F Chemical compound C1=CC(O)=CC=C1CC1=CC=C(O)C=C1 PXKLMJQFEQBVLD-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- 238000004945 emulsification Methods 0.000 description 2
- 230000006355 external stress Effects 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- 238000009730 filament winding Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000012779 reinforcing material Substances 0.000 description 2
- 150000005846 sugar alcohols Polymers 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- CBOLARLSGQXRBB-UHFFFAOYSA-N 1-(oxiran-2-yl)-n,n-bis(oxiran-2-ylmethyl)methanamine Chemical compound C1OC1CN(CC1OC1)CC1CO1 CBOLARLSGQXRBB-UHFFFAOYSA-N 0.000 description 1
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- JAHNSTQSQJOJLO-UHFFFAOYSA-N 2-(3-fluorophenyl)-1h-imidazole Chemical compound FC1=CC=CC(C=2NC=CN=2)=C1 JAHNSTQSQJOJLO-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical class C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003945 anionic surfactant Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000004359 castor oil Substances 0.000 description 1
- 235000019438 castor oil Nutrition 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 239000003093 cationic surfactant Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000001804 emulsifying effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000007380 fibre production Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- ZEMPKEQAKRGZGQ-XOQCFJPHSA-N glycerol triricinoleate Natural products CCCCCC[C@@H](O)CC=CCCCCCCCC(=O)OC[C@@H](COC(=O)CCCCCCCC=CC[C@@H](O)CCCCCC)OC(=O)CCCCCCCC=CC[C@H](O)CCCCCC ZEMPKEQAKRGZGQ-XOQCFJPHSA-N 0.000 description 1
- 238000009787 hand lay-up Methods 0.000 description 1
- LVHBHZANLOWSRM-UHFFFAOYSA-N methylenebutanedioic acid Natural products OC(=O)CC(=C)C(O)=O LVHBHZANLOWSRM-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 239000011208 reinforced composite material Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000001721 transfer moulding Methods 0.000 description 1
- 229920006305 unsaturated polyester Polymers 0.000 description 1
- 229920006337 unsaturated polyester resin Polymers 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Images
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、樹脂の強化材等に好適な炭素繊維ストランドに関し、更に詳述すればマトリックス樹脂に十分密着して引張強度の優れた複合材料を製造することのできる炭素繊維ストランドに関する。
【０００２】
【従来の技術】
炭素繊維は他の繊維と比較して強度や弾性率が高く、軽いという特徴を有するため、熱可塑性樹脂や熱硬化性樹脂をマトリックス樹脂とする複合材料の強化材として多用されている。この炭素繊維で強化した複合材料は、軽量で高強度であるので、航空宇宙産業を始めとし、各種の産業に広く利用されている。
【０００３】
熱硬化性樹脂系の複合材料を製造する方法としては、中間基材であるプリプレグを用いて賦形成型する方法がある。更に、炭素繊維ストランドを用いて引抜成形、レジントランスファーモールディング（ＲＴＭ）法、フィラメント・ワインディング（ＦＷ）法、シート・モールディング・コンパウンド（ＳＭＣ）法、バルク・モールディング・コンパウンド（ＢＭＣ）法、ハンドレイアップ法などによって熱硬化性樹脂系の複合材料を製造できる。
【０００４】
熱硬化性樹脂系複合材料の製造に用いられる熱硬化性のマトリックス樹脂としては例えばエポキシ樹脂、不飽和ポリエステル樹脂、ビニルエステル樹脂、フェノール樹脂等が挙げられるが、これらのうちでも特にエポキシ樹脂は耐熱性、物性等バランスの良い複合材料を与えるので好ましい。
【０００５】
エポキシ樹脂としては、ビスフェノールＡ型エポキシ樹脂、テトラグリシジルアミン、トリグリシジルアミン等の多官能エポキシ樹脂、ノボラック型エポキシ樹脂等が挙げられるが、特にビスフェノールＡ型エポキシ樹脂が接着性、物性等に優れ万能であるためマトリックス樹脂として広く使用されている。
【０００６】
複合材料を製造する際には、上述のように炭素繊維ストランドを用いてこれを加工するものであるが、この加工工程において、炭素繊維ストランドはガイド等で擦れることにより毛羽が生じやすく、取扱い性が悪くなる。この問題を避けるため、通常、炭素繊維ストランドにサイズ剤を付与し、炭素繊維ストランドの表面をサイズ剤でコートすることにより、ストランドの収束性を高め、耐擦過性や取扱い性を向上させる処理がなされている。
【０００７】
サイズ剤は一般的にマトリックス樹脂との接着性を考慮し、マトリックス樹脂がエポキシ樹脂の場合はエポキシ樹脂をサイズ剤に使用し（特許文献１、２）、マトリックス樹脂が不飽和マトリックス樹脂の場合はビニルエステル樹脂をサイズ剤に使用する提案がなされている。しかし、これらはサイズ剤と炭素繊維との接着性については考慮されていないため、その効果は不十分である。
【０００８】
一方、サイズ剤と炭素繊維との接着性を改善させることを目的として、炭素繊維の表面官能基と反応する可能性がある極性基を有するサイズ剤が提案されている（特許文献３、４、５、６）。これらのサイズ剤を使用した複合材料は、炭素繊維―マトリックス樹脂間の接着性指標の一つである層間剪断強度（ＩＬＳＳ）の測定値において優れた値を示している。しかし、これらサイズ剤を用いて製造した複合材料は、繊維軸方向に張力がかかると、炭素繊維全体に張力が分散すること無く比較的少数の炭素繊維に応力が集中してその少数の炭素繊維が破断することを順次繰返し、結果的に複合材料の全部を破壊することになる。このため、繊維軸方向の強度は期待するほど大きくならないのが現状である。
【０００９】
【特許文献１】
特公昭６２−５６２６６号公報（第１欄２７行〜第２欄第２行））
【特許文献２】
特開平７−１９７３８１号公報（段落番号（００３８）
【特許文献３】
特開昭５６−１６７７１５号公報（第２頁右上欄第５〜１２行）
【特許文献４】
特開昭６３−５０５７３号公報（第３頁第９〜１９行）
【特許文献５】
特開平１１−９３０７８号公報（第３頁、段落番号（００２０））
【特許文献６】
特開２００１−２０１８１号公報（請求項１）
【００１０】
【発明が解決しようとする課題】
本発明者は上記問題を解決するために炭素繊維に付与するサイズ剤につき種々検討しているうちに、熱処理をしたサイズ剤（硬化物）の動的粘弾性測定により得られるα緩和ピークのｔａｎδ（αｔａｎδ）と、β緩和ピークのｔａｎδ（βｔａｎδ）との積（αｔａｎδ・βｔａｎδ）の値がサイズ剤を付与した炭素繊維とマトリックス樹脂とからなる複合材の繊維軸方向の強度に大きな影響を与えることを発見した。更に詳細に検討した結果、αｔａｎδ及びβｔａｎδ単独では、複合材の繊維軸方向の強度との間に相関がないことも確認した。
【００１１】
本発明は、上記発見に基づき完成するに至ったもので、その目的とするところは、繊維軸方向の強度の優れた炭素繊維強化樹脂複合材料を製造することのできる炭素繊維ストランドを提供することにある。
【００１２】
【課題を解決するための手段】
上記目的を達成する本発明は、以下に記載するものである。
〔１〕 １３０℃で２時間熱処理したサイズ剤組成物のα緩和ピークのｔａｎδとβ緩和ピークのｔａｎδとの積αｔａｎδ・βｔａｎδが０．０４〜０．０７未満である未熱処理サイズ剤を少なくとも７０質量％含むサイズ剤組成物を付与してなる炭素繊維ストランド。
〔２〕 サイズ剤がエポキシ樹脂である〔１〕に記載の炭素繊維ストランド。
〔３〕 サイズ剤組成物中に３０質量％未満のＰＯ／ＥＯブロック共重合体を含む〔１〕又は〔２〕に記載の炭素繊維ストランド。
〔４〕 サイズ剤組成物の付与量が０．３〜５．０質量％である〔１〕〜〔３〕の何れかに記載の炭素繊維ストランド。
〔５〕 炭素繊維ストランドを構成する単繊維数が１０００〜５００００本である〔１〕〜〔４〕の何れかに記載の炭素繊維ストランド。
〔６〕 炭素繊維ストランドを構成する炭素繊維の、Ｘ線光電子分光法により測定される表面酸素濃度比Ｏ／Ｃが０．０５〜０．３である〔１〕〜〔５〕の何れかに記載の炭素繊維ストランド。
【００１３】
以下、本発明を詳細に説明する。
【００１４】
【発明の実施の形態】
本発明の炭素繊維ストランドは、炭素繊維ストランドにサイズ剤組成物を付与してなる。
【００１５】
炭素繊維ストランドは、炭素繊維（フィラメント）を束ねたものである。炭素繊維ストランドは１０００〜５００００本の炭素繊維からなるものが好ましい。
【００１６】
前記炭素繊維ストランドを構成する炭素繊維は、ポリアクリロニトリル（ＰＡＮ）系炭素繊維、ピッチ系炭素繊維、レーヨン系炭素繊維等が例示できる。これらの炭素繊維のうち、取り扱い性能、製造工程通過性能に適したＰＡＮ系炭素繊維が特に好ましい。ここで、ＰＡＮ系炭素繊維は、アクリロニトリル構造単位を主成分とし、イタコン酸、アクリル酸、アクリルエステル等のビニル単量体単位１０モル％以内を含有する共重合体を炭素繊維化したものが一般的である。
【００１７】
炭素繊維ストランドを構成する炭素繊維は、マトリックス樹脂との接着性を高めるために、Ｘ線光電子分光法により測定される表面酸素濃度比Ｏ／Ｃが０．０５〜０．３であることが好ましい。表面酸素濃度比Ｏ／Ｃが０．０５未満の場合は炭素繊維とマトリックス樹脂との接着性が劣り、これを用いて得られる複合材料の物性低下の原因となるので好ましくない。一方、表面酸素濃度比Ｏ／Ｃが０．３を超える場合は炭素繊維自体の強度が低下するので好ましくない。
【００１８】
炭素繊維の表面酸素濃度比Ｏ／Ｃを上記範囲にするためには、炭素繊維の製造工程において原料繊維を炭素化して炭素繊維を製造した後、得られた炭素繊維の表面処理を施すことにより行うことができる。
【００１９】
表面処理としては、液相処理、気相処理などがある。生産性、処理の均一性、安定性等の観点から、液相電解表面処理が好ましい。これら表面処理自体は公知のものである。
【００２０】
炭素繊維の表面処理の程度を管理するための指標としては、Ｘ線光電子分光法（ＸＰＳ）により測定される炭素繊維の表面酸素濃度比Ｏ／Ｃが好ましい。
【００２１】
本発明においては、Ｏ／Ｃは日本電子（株）製Ｘ線光電子分光器ＥＳＣＡ ＪＰＳ−９０００ＭＸを用いて、次の記載に従って求めるものである。即ち、予めサイジング剤を除去した炭素繊維を１０〜６Ｐａに減圧した前記ＥＳＣＡの測定室中に入れる。次いで、Ｍｇを対極として電子線加速電圧１０ｋＶ、１０ｍＡの条件で発生させたＸ線を炭素繊維に照射し、炭素原子、酸素原子から発生する光電子のスペクトルを測定する。Ｏ／Ｃは、それらの面積比から算出する。
【００２２】
発生する光電子の割合は各元素により異なる。日本電子（株）製Ｘ線光電子分光器ＥＳＣＡ ＪＰＳ−９０００ＭＸを用いる場合は、装置特性に起因して定める換算係数は２．６９である。
【００２３】
上記のようにして、必要により表面処理を施した炭素繊維は、充分に洗浄し、表面処理中に付着した電解質を除去することが好ましい。
【００２４】
本発明において、炭素繊維ストランドに付与するサイズ剤組成物は、エポキシ系サイズ剤を主成分とする。炭素繊維強化樹脂のマトリックス樹脂としてエポキシ樹脂が広く用いられている点から、サイズ剤組成物中５０質量％以上、さらに好ましくは６０質量％以上がエポキシ樹脂であることが好ましい。
【００２５】
エポキシ系サイズ剤としては、特に制限が無く、公知のエポキシ系サイズ剤が使用でき、具体的にはビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ダイマー酸型エポキシ樹脂、グリシジルエステル型エポキシ樹脂、アミノエポキシやノボラック型等の多官能エポキシ樹脂、スチレン・ブタジエン共重合体等のエラストマー変性エポキシ樹脂、ウレタン変性エポキシ樹脂等の変性エポキシ樹脂を例示できる。好ましくは、上記エポキシ樹脂は室温で液状であるものがよい。
【００２６】
市販品エポキシ系サイズ剤の化学構造式を以下に例示する。
【００２７】
【化１】
【化２】
【化３】
エポキシ系サイズ剤以外に各種の添加剤を配合しても良い。添加剤としては、特に限定されるものではないが、エポキシ系サイズ剤以外の公知のサイズ剤、分散剤、乳化剤、安定剤等を添加しても良い。
【００３１】
エポキシ系サイズ剤以外のサイズ剤としては、不飽和ポリエステル、ビニルエステル、アクリル樹脂等の公知のサイズ剤が使用できる。
【００３２】
また、製造する複合材料中で外部応力が一定の領域に集中せず、均一に分散されるように、前記サイズ剤組成物中には、有機微粒子として、プロピレンオキシド（ＰＯ）／エチレンオキシド（ＥＯ）ブロック共重合体を３０質量％未満含むことが好ましく、より好ましくは５質量％以上、３０質量％未満である。
【００３３】
ＰＯ／ＥＯブロック共重合体は乳化剤として公知のものが利用できる。具体的には、プロピレンオキシドとエチレンオキシドとのモル比が２〜８：８〜２で、２５℃での粘度が５０００〜３００００ｍＰａ・ｓのものが使用できる。
【００３４】
サイズ剤組成物中には炭素繊維の取扱い性や、耐擦過性、耐毛羽性、含浸性を向上させるため、平滑剤、界面活性剤等の補助成分を添加しても良い。
【００３５】
平滑剤としては、室温で液状である高級脂肪族系エーテル型ポリオキシエチレン付加物、高級脂肪族ポリオキシエチレン付加物、多価アルコールの高級脂肪酸エステル類、多価アルコールの高級脂肪酸エステル類ポリオキシエチレン付加物等が使用できる。
【００３６】
界面活性剤としては、ノニオン系、カチオン系、アニオン系の何れのものであっても良い。
【００３７】
本発明において使用するサイズ剤組成物は、上記サイズ剤及び必要により添加した添加剤を含み、且つ以下に述べる様に、その硬化物が所定の動的粘弾性特性を示すものである。即ち、本発明で用いるサイズ剤組成物を熱処理して硬化させたサイズ剤組成物は、図１に示す動的粘弾性測定曲線から得られるα緩和ピークのｔａｎδ（αｔａｎδ）とβ緩和ピークのｔａｎδ（βｔａｎδ）との積（αｔａｎδ・βｔａｎδ）が０．０４〜０．０７未満を示すもので、０．０４５〜０．０６６がより好ましい。
【００３８】
熱処理条件は、１３０℃で２時間である。
【００３９】
本発明者は、以下のように考えた。即ち、動的粘弾性測定から得られるｔａｎδは外部応力に対する熱エネルギーの散逸性を評価する指標であり、材料の靭性を推定することができる。具体的には、高ｔａｎδの材料であれば、高靭性であることが期待できる。サイズ剤がエポキシ樹脂の場合は、主に、高分子主鎖の分子運動に帰するα緩和と、局所運動に帰するβ緩和が存在し、両者が材料の靭性を支配する主要因と考えられる。従って、本発明者は両者を考慮したαｔａｎδとβｔａｎδとの積αｔａｎδ・βｔａｎδの値を高くすることにより、炭素繊維強化樹脂の物性を向上させることができると考えた。
【００４０】
ここで、αｔａｎδ・βｔａｎδが０．０４未満の場合は、サイズ剤の靭性が低くなり、炭素繊維強化樹脂の物性が劣化するので好ましくない。一方、αｔａｎδ・βｔａｎδが０．０７を超える場合は、炭素繊維束の集束性が劣るようになり、炭素繊維ストランドに対するマトリックス樹脂の含浸性が不均一になるので好ましくない。
【００４１】
炭素繊維ストランド中の上記サイズ剤組成物の含有量は０．３〜５．０質量％が好ましい。
【００４２】
サイズ剤組成物の付与量が０．３質量％未満の場合は、炭素繊維とマトリックス樹脂との接着性が不十分になり、炭素繊維ストランドの集束性も劣る。一方、サイズ剤組成物の付与量が５．０質量％を超える場合は、炭素繊維ストランドの開繊性が悪くなり、その結果複合材料製造の際の炭素繊維ストランドに対するマトリックス樹脂の含浸性が低下するので好ましくない。
【００４３】
サイズ剤組成物の炭素繊維ストランドに対する付与方法は、スプレー法、液浸法、転写法等、当業者に周知の方法を採択し得る。液浸法が、汎用性、効率性、付与の均一性に優れる点で好ましい。液浸法において炭素繊維ストランドをサイズ剤組成物液に浸漬する際、サイズ剤組成物液中に設けられた液没ローラー又は液浸ローラーを用いて開繊と絞りを繰り返し、サイズ剤組成物をストランドの内部まで十分浸透させることが好ましい。
【００４４】
サイズ剤組成物の付与方法としては、アセトン等の溶剤にエポキシ樹脂等を含むサイズ剤組成物を溶解させた溶液中に炭素繊維を浸漬する溶剤法と、乳化剤等を用いてサイズ剤組成物を水に乳化させた水系エマルジョン中に炭素繊維を浸漬するエマルジョン法とがある。人体への安全性及び自然環境の汚染を防止する観点からエマルジョン法が好ましい。
【００４５】
炭素繊維ストランドをサイズ剤組成物付与処理した後、通常乾燥工程に送り、サイズ剤組成物付与時に付着した分散媒の水あるいは溶剤を乾燥させる。乾燥工程で採用し得る乾燥方法としては、乾燥炉を通過させる方法、過熱したローラーに接触させる方法等、既知の方法が採択し得る。乾燥温度は特に制限されないが、汎用的な水系エマルジョンを使用する場合は通常８０℃〜２００℃に設定される。また、乾燥工程の後、２００℃以上の熱処理工程を更に設け、サイズ剤組成物の粘度を調整しても良い。
以下、実施例により本発明を更に具体的に説明する。
【００４６】
【実施例】
各炭素繊維ストランドの諸物性値は、以下の方法により測定した。
【００４７】
＜動的粘弾性測定＞
サイズ剤１００質量部、硬化剤（日立化成（株）製 カヤハード）３０質量部の割合で混合した樹脂組成物を１３０℃で２時間、金型を用いて成形・硬化させ、サイズ剤硬化物を得た。このサイズ剤硬化物を長さ３０ｍｍ、幅６ｍｍ、厚み３ｍｍとなるように調製し、動的粘弾性測定用試験片とした。
【００４８】
動的粘弾性は（株）ＵＢＭ製 動的粘弾性測定装置 型式：Ｒｈｏｇｅｌ Ｅ−４０００を用いて、昇温速度４℃／分、周波数１０Ｈｚの条件で−１００℃から２００℃の間で測定した。
【００４９】
図１に例示する動的粘弾性測定曲線から、α緩和ピークのｔａｎδ（αｔａｎδ）とβ緩和ピークのｔａｎδ（βｔａｎδ）とを求め、それらの積αｔａｎδ・βｔａｎδを算出した。
【００５０】
＜層間剪断強度（ＩＬＳＳ）＞
チバガイギー社製ＥＰＮ１１３８（商品名：フェノールノボラック型エポキシ樹脂）７０質量部、ジャパンエポキシレジン社製エピコート８３４（商品名：ビスフェノールＡ型エポキシ樹脂）１２質量部、同社製エピコート１００２（商品名：ビスフェノールＡ型エポキシ樹脂）１８質量部の割合で混合した樹脂組成物に、更に同社製硬化剤ＤＩＣＹ（ジシアンジアミド）５質量部、保土ケ谷化学製硬化促進剤ＤＣＭＵ（３−［３，４−ジクロロフェニル］−１，１−ジメチルウレア）１０質量部を加え、プリプレグ用樹脂組成物を作製した。フィルムコーターを用いて、この樹脂組成物を離型紙の上に塗布し、樹脂フィルムを得た。この樹脂フィルム上にサイズ組成物処理された炭素繊維ストランドを等間隔に引き揃えて並べた後、加熱して樹脂を該炭素繊維ストランドに含浸させることにより、目付１５０ｇ／ｍ２、樹脂含浸率３７質量％の一方向（ＵＤ）プリプレグを作製した。
【００５１】
上記にて作製したＵＤプリプレグを成形後の厚みが３ｍｍとなるように積層し、金型に入れ、１３０℃で２時間、６８６ｋＰａ（７ｋｇ／ｃｍ２）の圧力で成形し一方向の炭素繊維強化成形板（ＣＦＲＰ板）を作製した。このＣＦＲＰ板のＩＬＳＳをＡＳＴＭ−Ｄ−２３４４に準拠して測定した。測定温度は室温であった。
【００５２】
＜０°引張試験＞
チバガイギー社製ＥＰＮ１１３８（商品名：フェノールノボラック型エポキシ樹脂）７０質量部、ジャパンエポキシレジン社製エピコート８３４（商品名：ビスフェノールＡ型エポキシ樹脂）１２質量部、同社製エピコート１００２（商品名：ビスフェノールＡ型エポキシ樹脂）１８質量部の割合で混合した樹脂組成物に、更に同社製硬化剤ＤＩＣＹ（ジシアンジアミド）５質量部、保土ケ谷化学製硬化促進剤ＤＣＭＵ（３−［３，４−ジクロロフェニル］−１，１−ジメチルウレア）１０質量部を加え、プリプレグ用樹脂組成物を作製した。この樹脂組成物をフィルムコーターを用いて離型紙上に塗布し、樹脂フィルムを得た。この樹脂フィルム上にサイズ剤組成物処理された炭素繊維ストランドを等間隔に引き揃えて並べた後、加熱して樹脂を該炭素繊維ストランドに含浸させることにより、目付１５０ｇ／ｍ２、樹脂含浸率３７質量％のＵＤプリプレグを作製した。
【００５３】
作製したＵＤプリプレグを成形後の厚みが１ｍｍとなるように積層し、金型に入れ、１８０℃で２時間、６８６ｋＰａ（７ｋｇ／ｃｍ２）の圧力で成形し一方向の炭素繊維強化成形板（ＣＦＲＰ板）を作製した。このＣＦＲＰ板の０°引張試験をＡＳＴＭ−Ｄ−３０３９に準拠し、室温で行った。
【００５４】
実施例１〜６、比較例１〜３
Ｘ線光電子分光法により測定される炭素繊維の表面酸素濃度比Ｏ／Ｃが０．２である未サイジングの炭素繊維ストランド（東邦テナックス社製ベスファイト、２４０００フィラメント）をサイズ浴に連続的に浸漬させた。サイズ剤組成物水エマルジョンは、分子量の異なるビスフェノールＡ型エポキシ樹脂（ジャパンエポキシレジン社製エピコート８２８、１００１）、ノボラック型エポキシ樹脂（ジャパンエポキシレジン社製エピコート１５７Ｓ６５）、４官能アミノエポキシ樹脂（ジャパンエポキシレジン社製エピコート６０４）、エラストマー変性エポキシ樹脂（ジャパンエポキシレジン社製エピコートＹＸ３１０）、ウレタン変性エポキシ樹脂（大日本インキ化学工業株式会社製ＨＹＤＲＡＮ−Ｎ３２０）、ＰＯ／ＥＯブロック共重合体（ライオン株式会社製商品名レオコンＥＤ２７４Ｒ）の配合比を表１に示すように変化させたサイズ剤組成物１００質量部を硬化ひまし油エーテル１０質量部で乳化した水エマルジョンであった。
【００５５】
その後、サイズ剤組成物エマルジョンを含浸させた炭素繊維ストランドの水分を乾燥除去（１５０℃、３分）し、炭素繊維ストランドを得た。その際、浴濃度を調整することにより、表１に挙げる炭素繊維ストランドを得た。これらの炭素繊維ストランドを用いて、上記に挙げた各種評価試験を行った。その結果を表１、２にまとめて示した。
【００５６】
一方、上記各サイズ剤組成物を上記＜動的粘弾性測定＞で述べた方法に従って硬化させ、動的粘弾性測定用試験片を作製した。これらの試験片を用いて測定して得た動的粘弾性曲線からサイズ剤組成物のαｔａｎδ・βｔａｎδを算出した。結果を表１、２に示した。
【００５７】
【表１】
【表２】
【００５９】
【発明の効果】
本発明においては、所定条件で硬化させたサイズ剤組成物αｔａｎδ・βｔａｎδが０．０４〜０．０７未満の範囲内になるサイズ剤組成物を炭素繊維ストランドに付与しているので、０°引張り強度が優れた炭素繊維強化複合材料を得ることができる。
【図面の簡単な説明】
【図１】サイズ剤組成物の硬化物の動的粘弾性曲線の一例を示すチャートである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a carbon fiber strand suitable for a resin reinforcing material and the like, and more particularly to a carbon fiber strand capable of producing a composite material having excellent tensile strength by sufficiently adhering to a matrix resin.
[0002]
[Prior art]
Carbon fibers have high strength and elastic modulus as compared with other fibers and are light in weight. Therefore, carbon fibers are frequently used as a reinforcing material for a composite material using a thermoplastic resin or a thermosetting resin as a matrix resin. Since the composite material reinforced with carbon fiber is lightweight and high in strength, it is widely used in various industries including the aerospace industry.
[0003]
As a method for producing a thermosetting resin-based composite material, there is a method of forming and using a prepreg as an intermediate base material. Furthermore, pultruding using carbon fiber strands, resin transfer molding (RTM), filament winding (FW), sheet molding compound (SMC), bulk molding compound (BMC), and hand lay-up A thermosetting resin-based composite material can be manufactured by a method or the like.
[0004]
Examples of the thermosetting matrix resin used in the production of the thermosetting resin-based composite material include an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, and the like. It is preferable because it gives a composite material having a good balance of properties and physical properties.
[0005]
Examples of the epoxy resin include bisphenol A type epoxy resins, polyfunctional epoxy resins such as tetraglycidylamine and triglycidylamine, and novolak type epoxy resins. In particular, bisphenol A type epoxy resins are excellent in adhesiveness, physical properties, etc. Therefore, it is widely used as a matrix resin.
[0006]
When manufacturing a composite material, the carbon fiber strand is processed using a carbon fiber strand as described above, but in this processing step, the carbon fiber strand is liable to be fuzzed by being rubbed by a guide or the like, and the handling property is increased. Gets worse. In order to avoid this problem, a treatment is usually performed to impart a sizing agent to the carbon fiber strands and coat the surface of the carbon fiber strands with the sizing agent to enhance the convergence of the strands and improve the abrasion resistance and handleability. Has been done.
[0007]
The sizing agent generally takes into consideration the adhesiveness with the matrix resin. When the matrix resin is an epoxy resin, the epoxy resin is used as the sizing agent (Patent Documents 1 and 2), and when the matrix resin is an unsaturated matrix resin, It has been proposed to use a vinyl ester resin as a sizing agent. However, their effects are insufficient because the adhesion between the sizing agent and the carbon fibers is not considered.
[0008]
On the other hand, for the purpose of improving the adhesion between the sizing agent and the carbon fiber, sizing agents having a polar group that may react with the surface functional group of the carbon fiber have been proposed (Patent Documents 3 and 4, 5, 6). Composite materials using these sizing agents show excellent values in the measured values of the interlaminar shear strength (ILSS), which is one of the indicators of the adhesion between the carbon fiber and the matrix resin. However, when tension is applied in the fiber axis direction, the composite material manufactured using these sizing agents concentrates stress on a relatively small number of carbon fibers without dispersing the tension throughout the carbon fibers, and the small number of carbon fibers Is sequentially repeated, and as a result, all of the composite material is destroyed. Therefore, at present, the strength in the fiber axis direction does not increase as expected.
[0009]
[Patent Document 1]
JP-B-62-56266 (column 1, line 27 to column 2, line 2)
[Patent Document 2]
JP-A-7-197381 (paragraph number (0038))
[Patent Document 3]
JP-A-56-167715 (page 2, upper right column, lines 5 to 12)
[Patent Document 4]
JP-A-63-50573 (page 3, lines 9 to 19)
[Patent Document 5]
JP-A-11-93078 (page 3, paragraph number (0020))
[Patent Document 6]
JP 2001-18181 A (Claim 1)
[0010]
[Problems to be solved by the invention]
The present inventor has been studying various sizing agents to be applied to carbon fibers in order to solve the above-mentioned problem, and found that tan δ of the α relaxation peak obtained by dynamic viscoelasticity measurement of the heat-treated sizing agent (cured product). (alpha tan [delta]) and, beta relaxation peak of tanδ (β tan δ) and the product (α tan δ · β tan δ ) composite fiber axis values consisting of carbon fiber and the matrix resin imparted with sizing agent It has been found that it has a great effect on the directional strength. As a result of further detailed examination, it was confirmed that α tan δ and β tan δ alone had no correlation with the strength of the composite material in the fiber axis direction.
[0011]
The present invention has been completed based on the above findings, and it is an object of the present invention to provide a carbon fiber strand capable of producing a carbon fiber reinforced resin composite material having excellent strength in a fiber axis direction. It is in.
[0012]
[Means for Solving the Problems]
The present invention that achieves the above object is as described below.
[1] The unheated size of the sizing composition that has been heat-treated at 130 ° C. for 2 hours, wherein the product α tan δ · β tan δ of tan δ of the α relaxation peak and tan δ of the β relaxation peak is less than 0.04 to 0.07. A carbon fiber strand provided with a sizing composition containing at least 70% by mass of an agent.
[2] The carbon fiber strand according to [1], wherein the sizing agent is an epoxy resin.
[3] The carbon fiber strand according to [1] or [2], wherein the sizing composition contains less than 30% by mass of a PO / EO block copolymer.
[4] The carbon fiber strand according to any one of [1] to [3], wherein the applied amount of the sizing composition is 0.3 to 5.0% by mass.
[5] The carbon fiber strand according to any one of [1] to [4], wherein the number of single fibers constituting the carbon fiber strand is 1,000 to 50,000.
[6] Any of [1] to [5], wherein the surface oxygen concentration ratio O / C of the carbon fiber constituting the carbon fiber strand measured by X-ray photoelectron spectroscopy is 0.05 to 0.3. The carbon fiber strand according to the above.
[0013]
Hereinafter, the present invention will be described in detail.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The carbon fiber strand of the present invention is obtained by applying a sizing composition to a carbon fiber strand.
[0015]
The carbon fiber strand is a bundle of carbon fibers (filaments). The carbon fiber strand is preferably composed of 1,000 to 50,000 carbon fibers.
[0016]
Examples of the carbon fiber constituting the carbon fiber strand include polyacrylonitrile (PAN) -based carbon fiber, pitch-based carbon fiber, rayon-based carbon fiber, and the like. Among these carbon fibers, PAN-based carbon fibers suitable for handling performance and production process passing performance are particularly preferable. Here, the PAN-based carbon fiber is generally obtained by converting a copolymer containing a acrylonitrile structural unit as a main component and a vinyl monomer unit of 10% by mole or less such as itaconic acid, acrylic acid and acrylic ester into carbon fiber. It is a target.
[0017]
The carbon fibers constituting the carbon fiber strands preferably have a surface oxygen concentration ratio O / C of 0.05 to 0.3 measured by X-ray photoelectron spectroscopy in order to enhance the adhesion with the matrix resin. . If the surface oxygen concentration ratio O / C is less than 0.05, the adhesiveness between the carbon fiber and the matrix resin is poor, which is not preferable because it causes the deterioration of the physical properties of the composite material obtained using the same. On the other hand, when the surface oxygen concentration ratio O / C exceeds 0.3, the strength of the carbon fiber itself decreases, which is not preferable.
[0018]
In order to keep the surface oxygen concentration ratio O / C of the carbon fiber within the above range, the carbon fiber is carbonized in the carbon fiber production process to produce the carbon fiber, and then the obtained carbon fiber is subjected to a surface treatment. It can be carried out.
[0019]
The surface treatment includes a liquid phase treatment and a gas phase treatment. Liquid phase electrolytic surface treatment is preferred from the viewpoints of productivity, treatment uniformity, stability and the like. These surface treatments are known.
[0020]
As an index for controlling the degree of surface treatment of the carbon fiber, a surface oxygen concentration ratio O / C of the carbon fiber measured by X-ray photoelectron spectroscopy (XPS) is preferable.
[0021]
In the present invention, O / C is determined according to the following description using an X-ray photoelectron spectrometer ESCA JPS-9000MX manufactured by JEOL Ltd. That is, the carbon fiber from which the sizing agent has been removed in advance is put into the ESCA measurement chamber which has been reduced to 10 to 6 Pa. Next, the carbon fiber is irradiated with X-rays generated at an electron beam acceleration voltage of 10 kV and 10 mA using Mg as a counter electrode, and the spectrum of photoelectrons generated from carbon atoms and oxygen atoms is measured. O / C is calculated from their area ratio.
[0022]
The ratio of generated photoelectrons varies depending on each element. When using an X-ray photoelectron spectrometer ESCA JPS-9000MX manufactured by JEOL Ltd., the conversion factor determined based on the device characteristics is 2.69.
[0023]
As described above, it is preferable that the carbon fiber subjected to the surface treatment as necessary is sufficiently washed to remove the electrolyte adhered during the surface treatment.
[0024]
In the present invention, the sizing composition applied to the carbon fiber strand has an epoxy sizing agent as a main component. From the viewpoint that an epoxy resin is widely used as a matrix resin of a carbon fiber reinforced resin, it is preferable that 50% by mass or more, more preferably 60% by mass or more in the sizing composition is an epoxy resin.
[0025]
The epoxy sizing agent is not particularly limited, and a known epoxy sizing agent can be used. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, dimer acid type epoxy resin, glycidyl ester type epoxy resin, Examples include polyfunctional epoxy resins such as aminoepoxy and novolak, elastomer-modified epoxy resins such as styrene-butadiene copolymer, and modified epoxy resins such as urethane-modified epoxy resins. Preferably, the epoxy resin is liquid at room temperature.
[0026]
The chemical structural formula of a commercially available epoxy sizing agent is illustrated below.
[0027]
Embedded image
Embedded image
Embedded image
Various additives other than the epoxy sizing agent may be blended. The additive is not particularly limited, but a known sizing agent other than the epoxy sizing agent, a dispersant, an emulsifier, a stabilizer, and the like may be added.
[0031]
As the sizing agent other than the epoxy sizing agent, known sizing agents such as unsaturated polyester, vinyl ester, and acrylic resin can be used.
[0032]
In the sizing composition, propylene oxide (PO) / ethylene oxide (EO) is used as organic fine particles so that the external stress is not concentrated in a certain region and is uniformly dispersed in the composite material to be manufactured. The content of the block copolymer is preferably less than 30% by mass, more preferably 5% by mass or more and less than 30% by mass.
[0033]
As the PO / EO block copolymer, those known as emulsifiers can be used. Specifically, those having a molar ratio of propylene oxide to ethylene oxide of 2 to 8: 8 to 2 and a viscosity at 25 ° C. of 5,000 to 30,000 mPa · s can be used.
[0034]
Auxiliary components such as a leveling agent and a surfactant may be added to the sizing composition in order to improve the handling properties of the carbon fiber, the abrasion resistance, the fuzz resistance, and the impregnation.
[0035]
Examples of the leveling agent include higher aliphatic ether polyoxyethylene adducts, higher aliphatic polyoxyethylene adducts, higher fatty acid esters of polyhydric alcohols, higher fatty acid esters of polyhydric alcohols which are liquid at room temperature. Ethylene adducts and the like can be used.
[0036]
The surfactant may be any of nonionic, cationic and anionic surfactants.
[0037]
The sizing composition used in the present invention contains the above-mentioned sizing agent and optional additives, and as described below, the cured product thereof exhibits predetermined dynamic viscoelastic properties. That is, the sizing composition obtained by heat-treating the sizing composition used in the present invention has tan δ (α tan δ) and β relaxation peak of the α relaxation peak obtained from the dynamic viscoelasticity measurement curve shown in FIG. of tanδ (β tan δ) and the product (α tan δ · β tan δ ) is intended to indicate a less than 0.04 to 0.07, 0.045 to 0.066 is more preferable.
[0038]
The heat treatment condition is 130 ° C. for 2 hours.
[0039]
The present inventor considered as follows. That is, tan δ obtained from the dynamic viscoelasticity measurement is an index for evaluating the dissipative property of thermal energy with respect to external stress, and can estimate the toughness of the material. Specifically, a high tan δ material can be expected to have high toughness. When the sizing agent is an epoxy resin, there are mainly α relaxation attributed to the molecular motion of the polymer main chain and β relaxation attributed to the local motion, and both are considered to be the main factors controlling the toughness of the material. . Accordingly, the present inventors have by increasing the value of the product α tan δ · β tan δ of considering both alpha tan [delta] and beta tan [delta], considered that it is possible to improve the physical properties of carbon fiber reinforced plastic .
[0040]
Here, when α tan δ · β tan δ is less than 0.04, the toughness of the sizing agent is lowered, and the physical properties of the carbon fiber reinforced resin are undesirably deteriorated. On the other hand, when α tan δ · β tan δ exceeds 0.07, the convergence of the carbon fiber bundle becomes poor, and the impregnation of the matrix resin into the carbon fiber strand becomes ununiform, which is not preferable.
[0041]
The content of the sizing composition in the carbon fiber strand is preferably from 0.3 to 5.0% by mass.
[0042]
When the application amount of the sizing composition is less than 0.3% by mass, the adhesiveness between the carbon fiber and the matrix resin is insufficient, and the convergence of the carbon fiber strand is also poor. On the other hand, when the application amount of the sizing composition exceeds 5.0% by mass, the spreadability of the carbon fiber strand is deteriorated, and as a result, the impregnation of the matrix resin into the carbon fiber strand during the production of the composite material is reduced. Is not preferred.
[0043]
As a method for applying the sizing composition to the carbon fiber strand, a method known to those skilled in the art such as a spray method, a liquid immersion method, and a transfer method can be adopted. The liquid immersion method is preferred because it is excellent in versatility, efficiency, and uniformity of application. When the carbon fiber strand is immersed in the sizing composition liquid in the immersion method, opening and squeezing are repeated by using an immersion roller or an immersion roller provided in the sizing composition liquid, and the sizing composition is removed. It is preferable to sufficiently permeate the inside of the strand.
[0044]
As a method for applying the sizing composition, a solvent method in which carbon fibers are immersed in a solution obtained by dissolving a sizing composition containing an epoxy resin or the like in a solvent such as acetone, and a sizing composition using an emulsifier or the like. There is an emulsion method in which carbon fibers are immersed in an aqueous emulsion emulsified in water. The emulsion method is preferred from the viewpoint of safety to human bodies and prevention of pollution of the natural environment.
[0045]
After the carbon fiber strand is subjected to the sizing composition application treatment, it is usually sent to a drying step to dry the water or solvent of the dispersion medium adhered at the time of applying the sizing composition. As a drying method that can be adopted in the drying step, a known method such as a method of passing through a drying furnace or a method of contacting with a heated roller can be adopted. The drying temperature is not particularly limited, but is generally set at 80 ° C to 200 ° C when a general-purpose aqueous emulsion is used. After the drying step, a heat treatment step at 200 ° C. or higher may be further provided to adjust the viscosity of the sizing composition.
Hereinafter, the present invention will be described more specifically with reference to examples.
[0046]
【Example】
Various physical property values of each carbon fiber strand were measured by the following methods.
[0047]
<Dynamic viscoelasticity measurement>
A resin composition mixed at a ratio of 100 parts by mass of a sizing agent and 30 parts by mass of a curing agent (Kayahard manufactured by Hitachi Chemical Co., Ltd.) was molded and cured using a mold at 130 ° C. for 2 hours to obtain a cured sizing agent. Obtained. The cured product of the sizing agent was prepared so as to have a length of 30 mm, a width of 6 mm, and a thickness of 3 mm, and was used as a test piece for measuring dynamic viscoelasticity.
[0048]
The dynamic viscoelasticity was measured between -100 ° C and 200 ° C under the conditions of a temperature rising rate of 4 ° C / min and a frequency of 10Hz using a dynamic viscoelasticity measuring device manufactured by UBM Co., Ltd. Model: Rhogel E-4000. .
[0049]
From the dynamic viscoelasticity measurement curve illustrated in FIG. 1, tan δ (α tan δ) of the α relaxation peak and tan δ (β tan δ) of the β relaxation peak are obtained, and the product α tan δ · β tan δ is calculated. did.
[0050]
<Interlaminar shear strength (ILSS)>
70 parts by mass of EPN1138 (trade name: phenol novolak type epoxy resin) manufactured by Ciba Geigy Co., 12 parts by mass of Epicoat 834 (trade name: bisphenol A type epoxy resin) manufactured by Japan Epoxy Resin Co., Ltd., Epicoat 1002 (trade name: bisphenol A type) manufactured by Ciba Geigy The resin composition mixed at a ratio of 18 parts by mass of epoxy resin), 5 parts by mass of a curing agent DICY (dicyandiamide) manufactured by the same company, and a curing accelerator DCMU (3- [3,4-dichlorophenyl] -1,1 manufactured by Hodogaya Chemical). (Dimethylurea) (10 parts by mass) to prepare a resin composition for prepreg. This resin composition was applied on release paper using a film coater to obtain a resin film. After arranging the carbon fiber strands treated with the size composition on this resin film at equal intervals, the resin is impregnated into the carbon fiber strands by heating to obtain a basis weight of 150 g / m 2 and a resin impregnation rate of 37. A mass% unidirectional (UD) prepreg was prepared.
[0051]
The UD prepreg prepared above is laminated so that the thickness after molding becomes 3 mm, placed in a mold, molded at 130 ° C. for 2 hours under a pressure of 686 kPa (7 kg / cm 2 ), and reinforced in one direction with carbon fibers. A molded plate (CFRP plate) was produced. The ILSS of this CFRP plate was measured according to ASTM-D-2344. The measurement temperature was room temperature.
[0052]
<0 ° tensile test>
70 parts by mass of EPN1138 (trade name: phenol novolak type epoxy resin) manufactured by Ciba Geigy Co., 12 parts by mass of Epicoat 834 (trade name: bisphenol A type epoxy resin) manufactured by Japan Epoxy Resin Co., Ltd., Epicoat 1002 (trade name: bisphenol A type) manufactured by Ciba Geigy The resin composition mixed at a ratio of 18 parts by mass of epoxy resin), 5 parts by mass of a curing agent DICY (dicyandiamide) manufactured by the same company, and a curing accelerator DCMU (3- [3,4-dichlorophenyl] -1,1 manufactured by Hodogaya Chemical). (Dimethylurea) (10 parts by mass) to prepare a resin composition for prepreg. This resin composition was applied on release paper using a film coater to obtain a resin film. After arranging carbon fiber strands treated with the sizing composition on this resin film at equal intervals and then arranging them, the resin is impregnated with the carbon fiber strands by heating to give a basis weight of 150 g / m 2 and a resin impregnation rate. A 37 mass% UD prepreg was prepared.
[0053]
The prepared UD prepreg is laminated so as to have a thickness of 1 mm after molding, placed in a mold, and molded at 180 ° C. for 2 hours under a pressure of 686 kPa (7 kg / cm 2 ) to form a unidirectional carbon fiber reinforced molded plate ( CFRP plate). The CFRP plate was subjected to a 0 ° tensile test at room temperature in accordance with ASTM-D-3039.
[0054]
Examples 1 to 6, Comparative Examples 1 to 3
An unsized carbon fiber strand (Vesfight, 24000 filament, manufactured by Toho Tenax Co.) having a surface oxygen concentration ratio O / C of 0.2 measured by X-ray photoelectron spectroscopy is continuously immersed in a size bath. I let it. The water emulsion of the sizing composition is composed of bisphenol A type epoxy resins having different molecular weights (Epicoat 828, 1001 manufactured by Japan Epoxy Resin Co., Ltd.), novolak type epoxy resins (Epicoat 157S65 manufactured by Japan Epoxy Resin Co., Ltd.), and four-functional amino epoxy resin (Japan Epoxy) Resin Epicoat 604), Elastomer-modified epoxy resin (Epicoat YX310 manufactured by Japan Epoxy Resin), Urethane-modified epoxy resin (HYDRAN-N320 manufactured by Dainippon Ink and Chemicals, Inc.), PO / EO block copolymer (Lion Corporation) The water emulsion was obtained by emulsifying 100 parts by mass of a sizing composition having a blending ratio of trade name (Reocon ED274R, manufactured by trade name) as shown in Table 1 with 10 parts by mass of hardened castor oil ether.
[0055]
Thereafter, the water of the carbon fiber strand impregnated with the sizing composition emulsion was removed by drying (150 ° C., 3 minutes) to obtain a carbon fiber strand. At that time, the carbon fiber strands listed in Table 1 were obtained by adjusting the bath concentration. Using these carbon fiber strands, various evaluation tests described above were performed. The results are summarized in Tables 1 and 2.
[0056]
On the other hand, each of the above sizing compositions was cured according to the method described in the above <Dynamic viscoelasticity measurement> to prepare a test piece for dynamic viscoelasticity measurement. Α tan δ · β tan δ of the sizing composition was calculated from a dynamic viscoelastic curve obtained by using these test pieces. The results are shown in Tables 1 and 2.
[0057]
[Table 1]
[Table 2]
[0059]
【The invention's effect】
In the present invention, the sizing composition α tan δ · β tan δ cured under the predetermined conditions is applied to the carbon fiber strand so that the sizing composition is in the range of 0.04 to less than 0.07. A carbon fiber reinforced composite material having excellent 0 ° tensile strength can be obtained.
[Brief description of the drawings]
FIG. 1 is a chart showing an example of a dynamic viscoelasticity curve of a cured product of a sizing composition.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002319004A JP2004149979A (en) | 2002-10-31 | 2002-10-31 | Carbon fiber strand |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002319004A JP2004149979A (en) | 2002-10-31 | 2002-10-31 | Carbon fiber strand |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2004149979A true JP2004149979A (en) | 2004-05-27 |
Family
ID=32461995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002319004A Pending JP2004149979A (en) | 2002-10-31 | 2002-10-31 | Carbon fiber strand |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2004149979A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4973808B2 (en) * | 2010-03-30 | 2012-07-11 | 東レ株式会社 | Prepreg, fiber reinforced composite material, and method for producing prepreg |
| WO2012147401A1 (en) * | 2011-04-27 | 2012-11-01 | 東レ株式会社 | Prepreg, fiber-reinforced composite material, and method for producing prepreg |
| JP2019183377A (en) * | 2018-04-16 | 2019-10-24 | 三洋化成工業株式会社 | Fiber sizing agent, fiber bundle, fiber product, prepreg and molded body |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5841973A (en) * | 1981-09-07 | 1983-03-11 | 東邦レーヨン株式会社 | Emulsion type sizing agent for carbon fiber |
| JPS61225373A (en) * | 1985-03-27 | 1986-10-07 | 東邦レーヨン株式会社 | Carbon fiber bundle |
| JPH02307978A (en) * | 1989-05-17 | 1990-12-21 | Mitsubishi Rayon Co Ltd | Sizing agent for high-performance carbon fiber |
| JPH07279040A (en) * | 1993-08-25 | 1995-10-24 | Toray Ind Inc | Carbon fiber and its production |
| JPH08113876A (en) * | 1994-10-19 | 1996-05-07 | Toray Ind Inc | Carbon fiber and its production |
| JPH09228248A (en) * | 1996-02-14 | 1997-09-02 | Toray Ind Inc | Carbon fiber, its production and prepreg produced by using the carbon fiber |
| JP2002173873A (en) * | 2000-09-19 | 2002-06-21 | Toray Ind Inc | Carbon fiber strand, its package and method for producing carbon fiber sheet |
| JP2002317383A (en) * | 2001-04-25 | 2002-10-31 | Toho Tenax Co Ltd | Carbon fiber bundle for filament winding |
| JP2004169260A (en) * | 2002-10-31 | 2004-06-17 | Toho Tenax Co Ltd | Carbon fiber strand |
-
2002
- 2002-10-31 JP JP2002319004A patent/JP2004149979A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5841973A (en) * | 1981-09-07 | 1983-03-11 | 東邦レーヨン株式会社 | Emulsion type sizing agent for carbon fiber |
| JPS61225373A (en) * | 1985-03-27 | 1986-10-07 | 東邦レーヨン株式会社 | Carbon fiber bundle |
| JPH02307978A (en) * | 1989-05-17 | 1990-12-21 | Mitsubishi Rayon Co Ltd | Sizing agent for high-performance carbon fiber |
| JPH07279040A (en) * | 1993-08-25 | 1995-10-24 | Toray Ind Inc | Carbon fiber and its production |
| JPH08113876A (en) * | 1994-10-19 | 1996-05-07 | Toray Ind Inc | Carbon fiber and its production |
| JPH09228248A (en) * | 1996-02-14 | 1997-09-02 | Toray Ind Inc | Carbon fiber, its production and prepreg produced by using the carbon fiber |
| JP2002173873A (en) * | 2000-09-19 | 2002-06-21 | Toray Ind Inc | Carbon fiber strand, its package and method for producing carbon fiber sheet |
| JP2002317383A (en) * | 2001-04-25 | 2002-10-31 | Toho Tenax Co Ltd | Carbon fiber bundle for filament winding |
| JP2004169260A (en) * | 2002-10-31 | 2004-06-17 | Toho Tenax Co Ltd | Carbon fiber strand |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4973808B2 (en) * | 2010-03-30 | 2012-07-11 | 東レ株式会社 | Prepreg, fiber reinforced composite material, and method for producing prepreg |
| US20120328858A1 (en) * | 2010-03-30 | 2012-12-27 | Takayuki Fujiwara | Prepreg, fiber-reinforced composite material, and method for producing prepreg |
| TWI447028B (en) * | 2010-03-30 | 2014-08-01 | Toray Industries | Prepreg,fiber-reinforced composite material and method for manufacturing prepreg |
| US9139706B2 (en) | 2010-03-30 | 2015-09-22 | Toray Industries, Inc. | Prepreg, fiber-reinforced composite material, and method for producing prepreg |
| WO2012147401A1 (en) * | 2011-04-27 | 2012-11-01 | 東レ株式会社 | Prepreg, fiber-reinforced composite material, and method for producing prepreg |
| JP2019183377A (en) * | 2018-04-16 | 2019-10-24 | 三洋化成工業株式会社 | Fiber sizing agent, fiber bundle, fiber product, prepreg and molded body |
| JP7269781B2 (en) | 2018-04-16 | 2023-05-09 | 三洋化成工業株式会社 | Fiber sizing agents, fiber bundles, textile products, prepregs and moldings |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1403420B1 (en) | Sizing agent for carbon fiber, aqeous dispersion thereof; carbon fiber treated by sizing; sheet;form object comprising the carbon fiber; and carbon fiber;reinforced composite material | |
| JPWO2007060833A1 (en) | Carbon fiber bundles, prepregs and carbon fiber reinforced composite materials | |
| WO2004040055A1 (en) | Carbon fiber strand | |
| JP2005179826A (en) | Sizing coated carbon fiber and method for producing the same | |
| JP2011021281A (en) | Sizing agent for reinforcing fiber, synthetic fiber strand and fiber-reinforced composite material | |
| JP6115461B2 (en) | Carbon fiber coated with sizing agent and method for producing the same, carbon fiber reinforced thermoplastic resin composition | |
| JP2022164772A (en) | Method for producing sheet molding compound and molded product | |
| JP4518046B2 (en) | Oil for carbon fiber precursor and carbon fiber precursor | |
| JP2004169260A (en) | Carbon fiber strand | |
| JP5189547B2 (en) | Carbon fiber bundle and carbon fiber reinforced composite material | |
| JP4437420B2 (en) | Carbon fiber strands | |
| JP2004149979A (en) | Carbon fiber strand | |
| JP7167980B2 (en) | Epoxy resin composition for carbon fiber reinforced composite material, prepreg, carbon fiber reinforced composite material | |
| JP2005256226A (en) | Sizing-coated carbon fiber and method for producing the same | |
| JP2004316052A (en) | Oil formulation for producing carbon fiber and method for producing the carbon fiber | |
| JP6015027B2 (en) | Sizing agent, carbon fiber bundle and method for producing carbon fiber bundle | |
| JP2005264361A (en) | Oil agent for carbon fiber precursor | |
| JP2007145963A (en) | Intermediate for producing carbon fiber-reinforced composite material and carbon fiber-reinforced composite material | |
| JPH10131052A (en) | Sized carbon fiber strand and prepreg using the carbon fiber as reinforced fiber | |
| JP2004149721A (en) | Carbon fiber strand | |
| JP2016188271A (en) | Manufacturing method of prepreg | |
| JP3971664B2 (en) | Carbon fiber strand | |
| JP2004149978A (en) | Method for producing carbon fiber strand | |
| JP4155852B2 (en) | Carbon fiber strands | |
| JP2005281464A (en) | Polyamide-coated carbon fiber and its production method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050609 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20070611 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070619 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070816 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20080205 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20080617 |