JPH0478747B2 - - Google Patents
Info
- Publication number
- JPH0478747B2 JPH0478747B2 JP59247590A JP24759084A JPH0478747B2 JP H0478747 B2 JPH0478747 B2 JP H0478747B2 JP 59247590 A JP59247590 A JP 59247590A JP 24759084 A JP24759084 A JP 24759084A JP H0478747 B2 JPH0478747 B2 JP H0478747B2
- Authority
- JP
- Japan
- Prior art keywords
- aqueous solution
- carbon fiber
- carbon fibers
- treatment
- strength
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 41
- 239000004917 carbon fiber Substances 0.000 claims description 41
- 239000007864 aqueous solution Substances 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 13
- 238000004381 surface treatment Methods 0.000 claims description 9
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 21
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 12
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000002131 composite material Substances 0.000 description 9
- 239000011159 matrix material Substances 0.000 description 9
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 6
- 229920005989 resin Polymers 0.000 description 6
- 239000011347 resin Substances 0.000 description 6
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
- 239000000853 adhesive Substances 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 3
- -1 ammonium dihydrogen Chemical class 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000005611 electricity Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000004513 sizing Methods 0.000 description 3
- 239000004317 sodium nitrate Substances 0.000 description 3
- 235000010344 sodium nitrate Nutrition 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- FERIUCNNQQJTOY-UHFFFAOYSA-N Butyric acid Chemical compound CCCC(O)=O FERIUCNNQQJTOY-UHFFFAOYSA-N 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical class [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 2
- LWIHDJKSTIGBAC-UHFFFAOYSA-K tripotassium phosphate Chemical compound [K+].[K+].[K+].[O-]P([O-])([O-])=O LWIHDJKSTIGBAC-UHFFFAOYSA-K 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-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
- WWILHZQYNPQALT-UHFFFAOYSA-N 2-methyl-2-morpholin-4-ylpropanal Chemical compound O=CC(C)(C)N1CCOCC1 WWILHZQYNPQALT-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- USFZMSVCRYTOJT-UHFFFAOYSA-N Ammonium acetate Chemical compound N.CC(O)=O USFZMSVCRYTOJT-UHFFFAOYSA-N 0.000 description 1
- 239000005695 Ammonium acetate Substances 0.000 description 1
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229930182556 Polyacetal Natural products 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 description 1
- 239000004676 acrylonitrile butadiene styrene Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 235000019257 ammonium acetate Nutrition 0.000 description 1
- 229940043376 ammonium acetate Drugs 0.000 description 1
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- VZTDIZULWFCMLS-UHFFFAOYSA-N ammonium formate Chemical compound [NH4+].[O-]C=O VZTDIZULWFCMLS-UHFFFAOYSA-N 0.000 description 1
- VBIXEXWLHSRNKB-UHFFFAOYSA-N ammonium oxalate Chemical compound [NH4+].[NH4+].[O-]C(=O)C([O-])=O VBIXEXWLHSRNKB-UHFFFAOYSA-N 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- RQPZNWPYLFFXCP-UHFFFAOYSA-L barium dihydroxide Chemical compound [OH-].[OH-].[Ba+2] RQPZNWPYLFFXCP-UHFFFAOYSA-L 0.000 description 1
- 229910001863 barium hydroxide Inorganic materials 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000001723 curing Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- MSJMDZAOKORVFC-UAIGNFCESA-L disodium maleate Chemical compound [Na+].[Na+].[O-]C(=O)\C=C/C([O-])=O MSJMDZAOKORVFC-UAIGNFCESA-L 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 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 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 235000011056 potassium acetate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 229910000160 potassium phosphate Inorganic materials 0.000 description 1
- 235000011009 potassium phosphates Nutrition 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 239000011208 reinforced composite material Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910001961 silver nitrate Inorganic materials 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- WXMKPNITSTVMEF-UHFFFAOYSA-M sodium benzoate Chemical compound [Na+].[O-]C(=O)C1=CC=CC=C1 WXMKPNITSTVMEF-UHFFFAOYSA-M 0.000 description 1
- 239000004299 sodium benzoate Substances 0.000 description 1
- 235000010234 sodium benzoate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- ZNCPFRVNHGOPAG-UHFFFAOYSA-L sodium oxalate Chemical compound [Na+].[Na+].[O-]C(=O)C([O-])=O ZNCPFRVNHGOPAG-UHFFFAOYSA-L 0.000 description 1
- 229940039790 sodium oxalate Drugs 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 229910000162 sodium phosphate Inorganic materials 0.000 description 1
- 235000011008 sodium phosphates Nutrition 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 229920006305 unsaturated polyester Polymers 0.000 description 1
Description
〔産業上の利用分野〕
本発明は炭素繊維の表面処理に関するものであ
る。
〔従来の技術〕
炭素繊維で補強された複合材料は軽量でかつ強
度、弾性率にすぐれているため近年の価格の低下
とあいまつて、スポーツ、レジヤー用品、宇宙航
空機器材等幅広い分野にわたつて用途開発が進め
られている。しかるに、炭素繊維はマトリツクス
との接着強度が弱いため、表面を処理することに
よつて活性化させる必要があり、薬剤処理、気相
処理、電解処理等種々の表面処理法が提案されて
いる。その中でも電解酸化処理法は操作性の良
さ、反応制御の容易さ、省エネルギー等の見地か
ら実用的な表面処理方法である。
従来、炭素繊維とマトリツクスの接着強度を評
価するために層間剪断強度（ILSS）が用いられ
てきているが、一般にILSSはある一定の表面処
理レベル以上では表面処理の程度に対して鈍感に
なり、炭素繊維とマトリツクスの接着強度を直接
反映したものになつていないと考えられる。とこ
ろが複合材の剥離強度を表す繊維方向と90°方向
の引張り強さ（TS1）はILSSが飽和した後も表
面処理の強さに応じて上昇することが明らかにな
り、炭素繊維とマトリツクス接着強度を評価する
には、そのパラメーターとしてILSSを測定する
だけでなくTS1も併せて測る必要があることがわ
かつた。TS1を向上させるためには電解処理する
際の電流密度を強くすると効果的であるが、しか
し電流密度を強くしていくとエツチングが過度と
なるため電解処理後の炭素繊維の強度の低下の原
因となり不利である。
〔発明が解決しようとする問題点〕
そこで本発明者らは炭素繊維の強度を低下させ
ることなく、複合物のTS1を向上せしめることを
目的として鋭意検討した結果、本発明に到達し
た。
〔問題点を解決するための手段〕
すなわち本発明は、炭素繊維を陽極としてPH＞
７である水溶液で電解処理した後に、さらにPH≦
７である水溶液中で電解処理を行う点にある。
本発明法によると、炭素繊維の基質強度を下げ
ることなくTS1を向上させることが可能となる。
TS1を向上せしめる直接の要因は明らかではな
いが、炭素繊維表面に付着している不純物の除去
がTS1の向上に効果をもたらしていると考えられ
る。炭素繊維の表層にはブレカーサー油剤に由来
するケイ素酸化物や焼成過程で分解遊離した低分
子量の炭化物及び表面処理で表層が酸化されて生
成した低分子量の酸化物等の様々な不純物が付着
している。これら付着物は炭素繊維とマトリツク
の接着強度に何ら良好な効果を与えないばかり
か、その後のサイジング工程やプリプレグの作成
工程或いは作成された複合材料の性能に悪影響を
及ぼす恐れがある。サイジング工程では水和性の
酸化物がサイズ剤の凝集を引き起こし、又プリプ
レグ作成工程では、これら酸化物によつて過度に
硬化した樹脂成分が偏在するため均一なプリプレ
グ作成が困難になり、上記プリプレグを用いて作
成されたコンポジツトの性能が低いことが明らか
になつた。それに対して本発明では、これら付着
物を除去して清浄な表面を露出させること、及び
その結果起こる微小な空孔の増加によつて複合物
のTS1が向上したものと考えられる。実際、PH＞
７である水溶液中で炭素繊維を通電処理するとPH
≦７である水溶液で処理した場合と異なり、黒色
物質が多量に溶出するのが観察された。また上記
炭素繊維の表面をESCAで分析したところ、PH≦
７である水溶液中で処理した場合には除去できな
かつたケイ素酸化物が除去されていることが判明
したが、同時に導入された含酸素官能基密度が低
いことが明らかになつた。原因は定かではない
が、PH＞７である水溶液中で、電解酸化すると酸
素が炭素繊維の比較的グラフアイト化が進行して
いない部分に導入され、低分子量の酸化物として
表層から取り除かれるために全体としての密度が
低くなつているものと考えられる。ところが、該
炭素繊維を続けてPH≦７である水溶液中で電解酸
化したところ、効果的に含酸素官能基が導入され
ることがわかり、その結果複合物のTS1を一層向
上させることができるようになつた。
以上の様にして得られた炭素繊維は、従来の電
解酸化処理を施された炭素繊維と比較して複合物
のILSSを下げることなくTS1を大幅に向上する
ことができた。さらには電解酸化における電流密
度が従来の電解処理より低くても効果があるため
炭素繊維基質を損ねることなく特に弾性率が
25t／mm2から35t／mm2程度である中弾性の炭素繊維
に関しては処理した後も高いストランド強度を維
持することができた。
本発明に用いられる炭素繊維とはPAN、ピツ
チ、レーヨン等から製造された炭素繊維及び黒鉛
繊維の総称である。
またPH＞７である電解水溶液は特に制限はない
が水酸化ナトリウム、水酸化カリウム、水酸化バ
リウム等の水酸化物、アンモニア、リン酸ナトリ
ウム、リン酸カリウム、炭酸ナトリウム、炭酸水
素アンモニウム等の無機塩、酢酸ナトリウム、酢
酸カリウム、マレイン酸ナトリウム、安息香酸ナ
トリウム等の有機塩等の水溶液を単独で、もしく
は二種以上の混合物で用いる。さらにPH≦７であ
る電解水溶液はこれも特に制限はないがリン酸、
硝酸、硫酸、ホウ酸、炭酸等の無機酸、酢酸、酪
酸、アクリル酸、マレイン酸、シユウ酸等の有機
酸、硝酸ナトリウム、硝酸カリウム、硝酸銀、硝
酸アンモニウム、硫酸ナトリウム、硫酸アンモニ
ウム、硫酸水素アンモニウム、リン酸二水素アン
モニウム等の無機塩、ギ酸アンモニウム、酢酸ア
ンモニウム、シユウ酸アンモニウム、シユウ酸ナ
トリウム等の有機塩等の水溶液を単独で、もしく
は二種以上の混合物で用いる。
炭素繊維の処理方法は、従来の電解処理と同様
でバツチ式、連続式いずれでもよく、通電方法も
ローラー通電方式、オーバフロー方式いずれでも
さしつかえない。処理に用いる水溶液の濃度は
0.1wt％から20wt％、好ましくは5wt％程度、温
度は室温から100℃、好ましくは室温付近、処理
時間は双方の電解液中でそれぞれ数秒から数十
分、好ましくは５秒から５分が望ましい。洗浄効
果を上げるために電解液を流動させたり、不活性
ガスを用いたバブリングや超音波振動を利用する
ことができる。
以上の様にして得られた炭素繊維を複合材料に
用いる場合、マトリツクスには特に制限はない
が、通常熱硬化性樹脂としてエポキシ樹脂、ポリ
アセタール樹脂、不飽和ポリエステル等、熱可塑
性樹脂としてポリアミド、ポリエステル、ポリプ
ロピレン、ABS、ポリカーボネート等の樹脂が
用いられる。
〔実施例〕
以下、実施例によつて本発明を具体的に説明す
る。
実施例 １
弾性率が24t／mm2である炭素繊維トウ（炭素繊
維6000本相当）を５％NaOH水溶液中で30秒、
その後５％リン酸水溶液中で30秒それぞれ電流密
度1.5A／m2で通電処理したトウ(A)と５％リン酸
水溶液中で１分間通電処理したトウ(B)及び未処理
の炭素繊維トウをそれぞれ２ｍとり、蒸留水で10
分間洗浄した後、沸騰蒸留水10ｇで２時間抽出を
行つた。抽出液の吸光度をλ＝400nｍで測定す
ると第１表の様な結果が得られた。
本処理法で表面処理した炭素繊維が最も不純物
の付着が少ないことがわかる。
[Industrial Application Field] The present invention relates to surface treatment of carbon fibers. [Prior art] Composite materials reinforced with carbon fibers are lightweight and have excellent strength and elastic modulus, so as prices have declined in recent years, they are being used in a wide range of fields such as sports, leisure goods, and aerospace equipment materials. Development is underway. However, since carbon fibers have a weak adhesive strength with the matrix, they must be activated by surface treatment, and various surface treatment methods such as chemical treatment, gas phase treatment, and electrolytic treatment have been proposed. Among them, the electrolytic oxidation treatment method is a practical surface treatment method from the viewpoints of ease of operation, ease of reaction control, energy saving, etc. Conventionally, interlaminar shear strength (ILSS) has been used to evaluate the adhesive strength between carbon fiber and matrix, but ILSS generally becomes insensitive to the degree of surface treatment above a certain level of surface treatment. It is thought that this does not directly reflect the adhesive strength between carbon fiber and matrix. However, it has become clear that the tensile strength in the fiber direction and 90° direction (TS1), which indicates the peel strength of composite materials, increases depending on the strength of the surface treatment even after the ILSS is saturated, and the bond strength between carbon fiber and matrix increases. In order to evaluate this, it was found that it was necessary to measure not only ILSS but also TS1 as a parameter. In order to improve TS1, it is effective to increase the current density during electrolytic treatment, but increasing the current density causes excessive etching, which causes a decrease in the strength of carbon fiber after electrolytic treatment. This is disadvantageous. [Problems to be Solved by the Invention] Therefore, the present inventors conducted extensive studies aimed at improving the TS1 of a composite without reducing the strength of carbon fibers, and as a result, they arrived at the present invention. [Means for solving the problem] That is, the present invention uses carbon fiber as an anode to
After electrolytic treatment with an aqueous solution with pH 7, further pH≦
7, in which the electrolytic treatment is performed in an aqueous solution. According to the method of the present invention, it is possible to improve TS1 without reducing the matrix strength of carbon fibers. Although the direct factor that improves TS1 is not clear, it is thought that the removal of impurities attached to the carbon fiber surface has an effect on improving TS1. Various impurities adhere to the surface layer of carbon fibers, such as silicon oxides derived from breaker oil, low molecular weight carbides decomposed and liberated during the firing process, and low molecular weight oxides generated when the surface layer is oxidized during surface treatment. There is. These deposits not only do not have any good effect on the adhesive strength between the carbon fibers and the matrix, but also may have an adverse effect on the subsequent sizing process, prepreg production process, or performance of the composite material produced. In the sizing process, hydratable oxides cause agglomeration of the sizing agent, and in the prepreg production process, resin components excessively hardened by these oxides are unevenly distributed, making it difficult to produce uniform prepregs. It became clear that the performance of composites made using the method was poor. In contrast, in the present invention, it is considered that the TS1 of the composite was improved by removing these deposits to expose a clean surface and by increasing the number of minute pores as a result. In fact, PH＞
When carbon fiber is treated with electricity in an aqueous solution with a pH of 7.
Unlike the case of treatment with an aqueous solution where ≦7, a large amount of black material was observed to be eluted. Furthermore, when the surface of the above carbon fiber was analyzed by ESCA, it was found that PH≦
It was found that the silicon oxides that could not be removed when treated in an aqueous solution (No. 7) were removed, but at the same time it was also revealed that the density of the introduced oxygen-containing functional groups was low. The cause is not clear, but when electrolytically oxidized in an aqueous solution with a pH > 7, oxygen is introduced into the parts of the carbon fiber where graphitization has not progressed and is removed from the surface layer as a low molecular weight oxide. It is thought that the overall density is decreasing. However, when the carbon fiber was subsequently subjected to electrolytic oxidation in an aqueous solution with pH≦7, it was found that oxygen-containing functional groups were effectively introduced, and as a result, the TS1 of the composite could be further improved. It became. The carbon fiber obtained as described above was able to significantly improve TS1 without lowering the ILSS of the composite compared to carbon fiber subjected to conventional electrolytic oxidation treatment. Furthermore, because it is effective even when the current density in electrolytic oxidation is lower than that in conventional electrolytic treatment, it is possible to improve the elastic modulus without damaging the carbon fiber matrix.
For carbon fibers with medium elasticity of about 25t/mm 2 to 35t/mm 2 , high strand strength could be maintained even after treatment. The carbon fiber used in the present invention is a general term for carbon fiber and graphite fiber manufactured from PAN, pitch, rayon, etc. There are no particular restrictions on electrolytic aqueous solutions with pH>7, but hydroxides such as sodium hydroxide, potassium hydroxide, barium hydroxide, inorganic materials such as ammonia, sodium phosphate, potassium phosphate, sodium carbonate, ammonium hydrogen carbonate, etc. Salts, aqueous solutions of organic salts such as sodium acetate, potassium acetate, sodium maleate, sodium benzoate, etc. are used alone or in a mixture of two or more. Furthermore, the electrolytic aqueous solution with pH≦7 is phosphoric acid, although there are no particular restrictions on this.
Inorganic acids such as nitric acid, sulfuric acid, boric acid, carbonic acid, organic acids such as acetic acid, butyric acid, acrylic acid, maleic acid, oxalic acid, sodium nitrate, potassium nitrate, silver nitrate, ammonium nitrate, sodium sulfate, ammonium sulfate, ammonium hydrogen sulfate, phosphoric acid Aqueous solutions of inorganic salts such as ammonium dihydrogen, organic salts such as ammonium formate, ammonium acetate, ammonium oxalate, and sodium oxalate are used alone or in a mixture of two or more. The carbon fiber treatment method may be the same as conventional electrolytic treatment, either batch or continuous, and the energization method may be either roller energization or overflow. The concentration of the aqueous solution used for treatment is
0.1wt% to 20wt%, preferably about 5wt%, temperature from room temperature to 100°C, preferably around room temperature, and treatment time in both electrolytes from several seconds to several tens of minutes, preferably from 5 seconds to 5 minutes. . In order to improve the cleaning effect, it is possible to flow the electrolyte, use bubbling using an inert gas, or use ultrasonic vibration. When the carbon fibers obtained as described above are used in composite materials, there are no particular restrictions on the matrix, but thermosetting resins usually include epoxy resins, polyacetal resins, unsaturated polyesters, etc., and thermoplastic resins include polyamides, polyesters, etc. , polypropylene, ABS, polycarbonate, and other resins are used. [Example] Hereinafter, the present invention will be specifically explained with reference to Examples. Example 1 A carbon fiber tow (equivalent to 6000 carbon fibers) with an elastic modulus of 24 t/mm 2 was soaked in a 5% NaOH aqueous solution for 30 seconds.
Tow (A) was then energized in a 5% phosphoric acid aqueous solution for 30 seconds at a current density of 1.5 A/ m2 , tow (B) was energized in a 5% phosphoric acid aqueous solution for 1 minute, and untreated carbon fiber tow. Take 2 m of each and add 10 m of distilled water.
After washing for a minute, extraction was performed with 10 g of boiling distilled water for 2 hours. When the absorbance of the extract was measured at λ=400 nm, the results shown in Table 1 were obtained. It can be seen that the carbon fibers surface-treated using this treatment method have the least adhesion of impurities.
【表】
実施例 ２
実施例１で得た炭素繊維(A)、(B)及び(A)と同様の
条件で電解液を５％リン酸水溶液のかわりに５％
硝酸ナトリウム水溶液を使用して通電処理した炭
素繊維（Ａ−２）、(B)と同様条件で電解液を５％
リン酸水溶液のかわりに５％硝酸ナトリウム水溶
液、５％水酸化ナトリウム水溶液をそれぞれ使用
して通電処理した炭素繊維（Ｂ−２）、（Ｂ−３）
及び未処理の炭素繊維の表面をESCAで分析し、
Si2p／C1s、O1s／C1sを測定した。結果は第２表の
通りであつた。[Table] Example 2 Under the same conditions as the carbon fibers (A), (B), and (A) obtained in Example 1, the electrolyte was changed to 5% in place of the 5% phosphoric acid aqueous solution.
Carbon fibers treated with electricity using a sodium nitrate aqueous solution (A-2) and 5% electrolyte under the same conditions as (B).
Carbon fibers (B-2) and (B-3) treated with electricity using 5% sodium nitrate aqueous solution and 5% sodium hydroxide aqueous solution instead of phosphoric acid aqueous solution, respectively.
and analyzed the surface of untreated carbon fiber with ESCA,
Si 2p /C 1s and O 1s /C 1s were measured. The results were as shown in Table 2.
【表】
実施例 ３
弾性率が28t／mm2である炭素繊維を実施例１の
(A)、(B)の条件で電解質、電流密度をかえて処理し
た炭素繊維及び未処理の炭素繊維を充分水洗した
後、マトリツクス樹脂パイロフイル＃340（三菱レ
イヨン(株)製、商標）を用いて積層し、加熱、硬化
してTS1、ILSSを測定した。試験片の作成方法
及び試験法はTS1はASTM−D3039に、ILSSは
ASTM−D2344に従つた。また、それぞれのス
トランド強度を＃340樹脂を用いてJIS−Ｒ−7601
に基づいて測定した。さらにESCAで繊維表面の
O1s／C1sを測定した。結果は第３表の通りであつ
た。[Table] Example 3 Carbon fiber with an elastic modulus of 28t/mm 2 was used in Example 1.
After thoroughly washing the carbon fibers treated with different electrolytes and current densities under conditions (A) and (B) and untreated carbon fibers, matrix resin pyrofil #340 (manufactured by Mitsubishi Rayon Co., Ltd., trademark) was used. The TS1 and ILSS values were measured after lamination, heating, and curing. The test piece preparation method and test method are based on ASTM-D3039 for TS1, and for ILSS.
According to ASTM-D2344. In addition, the strength of each strand was measured using #340 resin according to JIS-R-7601.
Measured based on. Furthermore, ESCA is used to improve the fiber surface.
O 1s /C 1s was measured. The results were as shown in Table 3.
【表】【table】
本発明法により、層間剪断強度ばかりでなく繊
維方向と90°方向の引張り強さも向上した炭素繊
維強化複合材料が得られる。
By the method of the present invention, a carbon fiber reinforced composite material with improved not only interlaminar shear strength but also tensile strength in the 90° direction with respect to the fiber direction can be obtained.
Claims (1)
を陽極としてPH＞７である水溶液中で電解処理し
た後に、さらにPH≦７である水溶液中で電解処理
せしめることを特徴とする炭素繊維の表面処理
法。1. A method for surface treatment of carbon fibers, which comprises electrolytically treating the carbon fibers in an aqueous solution with a pH>7 using the carbon fibers as an anode, and then electrolytically treating the carbon fibers in an aqueous solution with a pH≦7. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59247590A JPS61124677A (en) | 1984-11-22 | 1984-11-22 | Surface treatment of carbon fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59247590A JPS61124677A (en) | 1984-11-22 | 1984-11-22 | Surface treatment of carbon fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61124677A JPS61124677A (en) | 1986-06-12 |
| JPH0478747B2 true JPH0478747B2 (en) | 1992-12-14 |
Family
ID=17165765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59247590A Granted JPS61124677A (en) | 1984-11-22 | 1984-11-22 | Surface treatment of carbon fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61124677A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2592293B2 (en) * | 1987-06-01 | 1997-03-19 | 三菱レイヨン株式会社 | Surface treatment method for carbon fiber |
| JP3136883B2 (en) * | 1994-01-28 | 2001-02-19 | 東レ株式会社 | Carbon fiber reinforced resin composite and prepreg |
| US11434581B2 (en) * | 2015-02-03 | 2022-09-06 | Nanocomp Technologies, Inc. | Carbon nanotube structures and methods for production thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5643858A (en) * | 1979-09-17 | 1981-04-22 | Nec Corp | Digital conference telephone system |
| JPS5824554A (en) * | 1981-08-07 | 1983-02-14 | Mitsubishi Gas Chem Co Inc | Separation of malononitrile |
-
1984
- 1984-11-22 JP JP59247590A patent/JPS61124677A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5643858A (en) * | 1979-09-17 | 1981-04-22 | Nec Corp | Digital conference telephone system |
| JPS5824554A (en) * | 1981-08-07 | 1983-02-14 | Mitsubishi Gas Chem Co Inc | Separation of malononitrile |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61124677A (en) | 1986-06-12 |
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