JPS6335712B2 - - Google Patents
Info
- Publication number
- JPS6335712B2 JPS6335712B2 JP12068781A JP12068781A JPS6335712B2 JP S6335712 B2 JPS6335712 B2 JP S6335712B2 JP 12068781 A JP12068781 A JP 12068781A JP 12068781 A JP12068781 A JP 12068781A JP S6335712 B2 JPS6335712 B2 JP S6335712B2
- Authority
- JP
- Japan
- Prior art keywords
- treatment
- steel plate
- steel sheet
- galvanized steel
- plated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000011282 treatment Methods 0.000 claims description 44
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 claims description 30
- 229910000831 Steel Inorganic materials 0.000 claims description 26
- 239000011651 chromium Substances 0.000 claims description 26
- 239000010959 steel Substances 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 25
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 19
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 17
- 229910052804 chromium Inorganic materials 0.000 claims description 17
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 16
- 239000008397 galvanized steel Substances 0.000 claims description 16
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 14
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 claims description 13
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 238000004381 surface treatment Methods 0.000 claims description 4
- 238000007747 plating Methods 0.000 claims description 3
- 238000009713 electroplating Methods 0.000 claims description 2
- 238000005275 alloying Methods 0.000 claims 1
- 238000012360 testing method Methods 0.000 description 21
- 239000007788 liquid Substances 0.000 description 15
- 230000007797 corrosion Effects 0.000 description 12
- 238000005260 corrosion Methods 0.000 description 12
- 239000003638 chemical reducing agent Substances 0.000 description 10
- 238000000576 coating method Methods 0.000 description 10
- 239000003973 paint Substances 0.000 description 9
- 239000011248 coating agent Substances 0.000 description 8
- 150000003839 salts Chemical class 0.000 description 7
- 239000007921 spray Substances 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 239000002699 waste material Substances 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 238000009778 extrusion testing Methods 0.000 description 4
- -1 hydrogen ions Chemical class 0.000 description 4
- 229920000298 Cellophane Polymers 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 230000005856 abnormality Effects 0.000 description 3
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 3
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 229920002125 Sokalan® Polymers 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 239000004584 polyacrylic acid Substances 0.000 description 2
- WQGWDDDVZFFDIG-UHFFFAOYSA-N pyrogallol Chemical compound OC1=CC=CC(O)=C1O WQGWDDDVZFFDIG-UHFFFAOYSA-N 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 241001163841 Albugo ipomoeae-panduratae Species 0.000 description 1
- 101100008044 Caenorhabditis elegans cut-1 gene Proteins 0.000 description 1
- FBPFZTCFMRRESA-KVTDHHQDSA-N D-Mannitol Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-KVTDHHQDSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- 229930195725 Mannitol Natural products 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910000611 Zinc aluminium Inorganic materials 0.000 description 1
- 125000003668 acetyloxy group Chemical group [H]C([H])([H])C(=O)O[*] 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 229920000180 alkyd Polymers 0.000 description 1
- HXFVOUUOTHJFPX-UHFFFAOYSA-N alumane;zinc Chemical compound [AlH3].[Zn] HXFVOUUOTHJFPX-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 125000001951 carbamoylamino group Chemical group C(N)(=O)N* 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- VQWFNAGFNGABOH-UHFFFAOYSA-K chromium(iii) hydroxide Chemical compound [OH-].[OH-].[OH-].[Cr+3] VQWFNAGFNGABOH-UHFFFAOYSA-K 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 125000003700 epoxy group Chemical group 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 125000001301 ethoxy group Chemical group [H]C([H])([H])C([H])([H])O* 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 239000008103 glucose Substances 0.000 description 1
- 150000002334 glycols Chemical class 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229920000592 inorganic polymer Polymers 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000000594 mannitol Substances 0.000 description 1
- 235000010355 mannitol Nutrition 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000000956 methoxy group Chemical group [H]C([H])([H])O* 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 235000010981 methylcellulose Nutrition 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229920001451 polypropylene glycol Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 229940079877 pyrogallol Drugs 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- SCPYDCQAZCOKTP-UHFFFAOYSA-N silanol Chemical compound [SiH3]O SCPYDCQAZCOKTP-UHFFFAOYSA-N 0.000 description 1
- 125000005372 silanol group Chemical group 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 125000003396 thiol group Chemical group [H]S* 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229920003169 water-soluble polymer Polymers 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/24—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds
- C23C22/30—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds containing also trivalent chromium
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
- C23C2222/20—Use of solutions containing silanes
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Treatment Of Metals (AREA)
- Electroplating Methods And Accessories (AREA)
Description
本発明はメツキ鋼板の表面に耐食性、加工性、
塗装密着性を有するクロメート皮膜を形成させる
ためのメツキ鋼板のクロメート処理方法に関する
ものである。
従来から亜鉛或いはアルミニウムなどのメツキ
が施されたメツキ鋼板は、未塗装のまま或いは塗
装して更には之等の両者が組み合わされて使用さ
れている。そこで之等の用途に応じて防錆及び塗
装後の塗膜の密着性、耐食性の向上を目的とし
て、主としてクロム酸系処理またはリン酸塩系処
理が行なわれている。クロメート皮膜を形成させ
るためのクロム酸系処理としては、鋼板表面と処
理液とのエツチング反応を伴う化学反応によるも
の、６価クロムの一部を還元剤により３価クロム
に還元させて６価クロム及び３価クロムが共存す
る処理液を鋼板表面に塗布するもの、及び電解処
理法によるものなどに区分出来る。この中で金属
表面との化学反応によつてクロメート皮膜を形成
させる方法では、母材表面の金属（Zn、Alなど）
が金属イオンとなり同時に処理液中の水素イオン
が消費される。その結果、被処理母材の処理量に
応じて液中の遊離酸濃度が減少し、遂には適正な
クロメート皮膜が形成されなくなり、その処理液
は廃液処分にして新しい処理液に更新しなければ
ならない。
しかしながら、ここで廃液処分にするクロメー
ト処理液中には公害規制物質である多量の６価ク
ロム及び３価クロムを含んでいるので何等かの方
法でクロムを除去する無公害化の処理を行なわな
ければならないが、この廃液処理は非常に厄介で
あるばかりでなく多額の処理費を要する。
こうした廃液処理上の問題から最近では廃クロ
ム酸を生じない塗布型クロメート処理液の開発が
盛んに行なわれている。塗布型クロメート処理液
は６価クロムと還元剤によつて６価クロムが還元
された結果生ずる３価クロムを含み、或いは更に
造膜剤としてシリカゾル、アルミナゾル、アルキ
ルシリケートなどの無機高分子またはポリビニル
アルコール、ポリアクリル酸、ポリアクリル酸エ
ステルなどの水溶性高分子を添加したものを用い
て耐食性の向上を図つているのが一般的である。
また、６価クロムを３価クロムに還元させる還
元剤としては、一般に有機系還元剤として、エチ
レングリコール、プロピレングリコール、ポリプ
ロピレングリコールなどのグリコール類；メタノ
ール、エタノールなどの１価アルコール類；及び
ピロガロール、ブドウ糖、サツカロース、メチル
セルロース、マンニトールなどの多価アルコール
類；無機系還元剤として過酸化水素などがある。
こうした従来の還元剤では処理液の６価クロムと
３価クロムが一定の比率を保ち且つ水酸化クロム
などの沈殿或いは液のゲル化などを生ずることな
く安定な処理浴として維持するのが困難であつた
り、或いは処理浴が或る程度維持出来てもその反
面被処理板の耐食性、加工性、塗膜密着性などの
性能の点で充分でなかつたことなどが挙げられ
る。
本発明者等は上記問題点を解決すべく鋭意研究
の結果、シランカツプリング剤を還元剤として用
いることにより従来の公知技術では得られない優
れた処理浴の安定性、耐食性、加工性、塗膜密着
性を示すこと、及び亜鉛メツキ鋼板のみならず、
アルミニウムなど他の金属をメツキ金属として用
いたメツキ鋼板にも適用可能であることを見出し
本発明を完成するに到つた。
即ち、本発明は無水クロム酸（CrO3）溶液に
シランカツプリング剤を添加して無水クロム酸の
一部を還元させて得られた液の組成を無水クロム
酸0.1〜1mol／、３価クロムと６価クロムとの
モル比（Cr+3／Cr+6）を0.05〜0.7とした処理液
でメツキ鋼板を表面処理することを特徴とするメ
ツキ鋼板のクロメート処理方法に関するものであ
る。
以下、本発明を更に詳細に説明する。
本発明に用いる無水クロム酸は従来鋼板の表面
処理に用いられているもので充分である。
またシランカツプリング剤は一般式YRSiX3で
表わされ、Ｘはケイ素原子に結合している加水分
解性の基を表わし、アルコキシ基及びアセトキシ
基などがある。またＹは有機官能基を示し、ビニ
ル基、メタクリロキシ基、ウレイド基、環状エポ
キシ基、グリシドキシ基、メルカプト基、アミノ
基、ジアミノ基などが挙げられる。シランカツプ
リング剤による６価クロムの還元機構は次の通り
である。
シランカツプリング剤をクロム酸水溶液中に添
加すると之等の基または原子は加水分解を受けて
下式の様にシラノール及びHXを生ずる。
YRSiX3＋H2O→YRSi（OH）3＋3HX
例えばＹがメトキシ基及びエトキシ基の時、
HXはそれぞれメタノール、エタノールとなり、
この副生されたアルコールによつて６価クロムは
３価クロムに還元される。
本発明に用いる処理液は処理液１当り無水ク
ロム酸0.1〜1mol／を含み且つシランカツプリ
ング剤によつて還元された３価クロムを３価クロ
ムと６価クロムのモル比（Cr+3／Cr+6）で0.05〜
0.7含む様に調整する。処理液の組成をこの様に
限定するのは次の理由による。即ち、無水クロム
酸の濃度が0.1mol／未満では工業的生産工程
で行なわれている３〜７秒間程度の短時間処理で
は耐食性の優れた皮膜が形成されず、1mol／
を越えると皮膜が黄味を呈し外観が損われるので
好ましくない。
また３価クロムと６価クロムのモル比が0.05未
満では耐食性、加工性などの性能向上が期待され
ず、0.7を越えると３価クロムの含有率が非常に
高くなるので逆に耐食性が却つて低下するからで
ある。
本発明において処理対象とするメツキ鋼板とし
ては亜鉛アルミニウムなどの溶融メツキまたは電
気メツキを鋼板に施したメツキ鋼板が用いられ、
また亜鉛メツキ鋼板としては単に亜鉛をメツキし
ただけのメツキ鋼板の他に、亜鉛メツキ後更に高
温加熱して合金化処理を施したメツキ鋼板も用い
られる（本発明においては上記処理対象の各鋼板
をメツキ鋼板と総称する）。
かかるメツキ鋼板を本発明において用いる処理
液によつて表面処理する方法は通常実施されてい
る方法に従い、メツキ鋼板を必要に応じて脱脂
後、水洗して表面を清浄にした後に、浸漬法、ス
プレー法、ロールコーター法、ロール絞り法、エ
アーナイフ絞り法などの方法により処理液を鋼板
表面に塗布する。
乾燥は水分を蒸発する程度で良く、望ましくは
板温として70〜100℃が好ましい。
シランカツプリング剤を還元剤として用いると
従来の還元剤では得られない数々の優れた性能を
得ることが出来る。
之等の性能としては先ず第一に処理浴の安定性
が挙げられる。一般に３価クロムを含有するクロ
メート処理液はPHが３を越えると沈殿物が生じた
りゲル化する傾向がある。しかし、シランカツプ
リング剤を還元剤として使用した場合にはPHは
5.0程度でも何等液の安定性に問題はない。
次に第二の特徴として、メツキ鋼板の耐食性、
加工性も極めて優れている。これはシランカツプ
リング剤の本来の機能である加水分解によつて生
成されるシラノール基が金属表面に吸着されると
共にCrO4 -、Cr（OH）3などとの間で架橋反応など
の化学反応を起こして強固なクロメート皮膜を形
成することが考えられる。また一方、シランカツ
プリング剤は有機官能基をも有しているのでアル
キド、アクリル、エポキシ塗料などの塗膜密着性
にも優れている。
本発明のクロメート処理方法は、それによつて
処理されたメツキ鋼板の耐食性、加工性、塗膜密
着性を大幅に向上させるものであり、また本発明
のクロメート処理方法は塗布型であるため処理液
の老化もなく、従つて廃液処理の必要性もないこ
とと相俟つて産業上非常に価値の高いものであ
る。
以下、実施例、比較例によつて本発明を更に説
明する。
実施例
各種金属メツキ鋼板の表面に本発明方法による
クロメート処理液を塗布して熱風乾燥してクロメ
ート処理鋼板を得た。メツキ鋼板の種類、処理液
の調整方法及びその組成、PH、塗布方法、処理方
法、皮膜量（クロム付着量）、乾燥温度（板温）
などの詳細な条件を第１表に示す。
The present invention provides corrosion resistance, workability, and
The present invention relates to a method for chromate treatment of galvanized steel sheets to form a chromate film with paint adhesion. Conventionally, galvanized steel sheets plated with zinc or aluminum have been used uncoated, coated, or in combination. Therefore, depending on the intended use, chromic acid treatment or phosphate treatment is mainly carried out for the purpose of preventing rust and improving the adhesion and corrosion resistance of the coated film after painting. Chromate-based treatments for forming chromate films include chemical reactions involving etching reactions between the steel plate surface and the treatment solution, and hexavalent chromium by reducing a portion of hexavalent chromium to trivalent chromium using a reducing agent. It can be divided into two types: one in which a treatment solution containing trivalent chromium is applied to the surface of the steel plate, and one in which an electrolytic treatment method is used. Among these, in the method of forming a chromate film through a chemical reaction with the metal surface, the metal (Zn, Al, etc.) on the surface of the base material
becomes metal ions, and at the same time hydrogen ions in the processing solution are consumed. As a result, the free acid concentration in the solution decreases according to the amount of treated base material, and eventually an appropriate chromate film is no longer formed, and the treatment solution must be disposed of as waste and replaced with a new treatment solution. No. However, since the chromate treatment liquid to be disposed of as waste liquid contains a large amount of hexavalent chromium and trivalent chromium, which are pollution control substances, it is necessary to perform a pollution-free treatment to remove chromium by some method. However, this waste liquid treatment is not only very troublesome but also requires a large amount of treatment cost. Due to these problems in waste liquid treatment, there has recently been much effort to develop coating-type chromate treatment liquids that do not generate waste chromic acid. The coating type chromate treatment solution contains hexavalent chromium and trivalent chromium produced as a result of reduction of hexavalent chromium with a reducing agent, or further contains inorganic polymers such as silica sol, alumina sol, alkyl silicate, or polyvinyl alcohol as a film forming agent. It is common to use a material to which water-soluble polymers such as polyacrylic acid, polyacrylic acid ester, etc. are added to improve corrosion resistance. In addition, as reducing agents for reducing hexavalent chromium to trivalent chromium, organic reducing agents generally include glycols such as ethylene glycol, propylene glycol, and polypropylene glycol; monohydric alcohols such as methanol and ethanol; and pyrogallol, Polyhydric alcohols such as glucose, sutucarose, methyl cellulose, and mannitol; hydrogen peroxide as an inorganic reducing agent.
With these conventional reducing agents, it is difficult to maintain a stable processing bath in which the hexavalent chromium and trivalent chromium in the processing solution maintain a constant ratio and do not cause precipitation of chromium hydroxide or gelation of the solution. For example, the temperature may be too high, or even if the treatment bath can be maintained to a certain extent, the performance of the plate to be treated, such as corrosion resistance, workability, and coating adhesion, may not be sufficient. As a result of intensive research to solve the above-mentioned problems, the present inventors have found that by using a silane coupling agent as a reducing agent, excellent processing bath stability, corrosion resistance, processability, and coating properties that could not be obtained with conventionally known techniques. In addition to showing film adhesion and galvanized steel sheets,
We have completed the present invention by discovering that it is also applicable to plated steel plates using other metals such as aluminum as the plated metal. That is, in the present invention, a silane coupling agent is added to a chromic anhydride (CrO 3 ) solution to reduce a part of the chromic anhydride, and the composition of the resulting solution is changed to 0.1 to 1 mol of chromic anhydride/trivalent chromium. The present invention relates to a chromate treatment method for a galvanized steel sheet, characterized in that the surface of the galvanized steel sheet is treated with a treatment liquid having a molar ratio (Cr +3 /Cr +6 ) of chromium and hexavalent chromium of 0.05 to 0.7. The present invention will be explained in more detail below. As the chromic anhydride used in the present invention, those conventionally used for surface treatment of steel plates are sufficient. The silane coupling agent is represented by the general formula YRSiX 3 , where X represents a hydrolyzable group bonded to a silicon atom, such as an alkoxy group and an acetoxy group. Further, Y represents an organic functional group, and examples thereof include a vinyl group, a methacryloxy group, a ureido group, a cyclic epoxy group, a glycidoxy group, a mercapto group, an amino group, and a diamino group. The reduction mechanism of hexavalent chromium by the silane coupling agent is as follows. When a silane coupling agent is added to an aqueous chromic acid solution, these groups or atoms undergo hydrolysis to produce silanol and HX as shown in the following formula. YRSiX 3 +H 2 O→YRSi(OH) 3 +3HX For example, when Y is a methoxy group or an ethoxy group,
HX becomes methanol and ethanol respectively,
Hexavalent chromium is reduced to trivalent chromium by this by-produced alcohol. The treatment solution used in the present invention contains 0.1 to 1 mol of chromic anhydride per treatment solution, and converts trivalent chromium reduced by a silane coupling agent into a molar ratio of trivalent chromium to hexavalent chromium (Cr +3 / Cr +6 ) from 0.05
Adjust to include 0.7. The reason why the composition of the processing liquid is limited in this way is as follows. In other words, if the concentration of chromic anhydride is less than 0.1 mol/mol, a film with excellent corrosion resistance will not be formed in the short-time treatment of about 3 to 7 seconds, which is carried out in industrial production processes, and if the concentration of chromic acid anhydride is less than 1 mol/mol/
Exceeding this is not preferable because the film will take on a yellowish tinge and the appearance will be impaired. Furthermore, if the molar ratio of trivalent chromium to hexavalent chromium is less than 0.05, no improvement in performance such as corrosion resistance or workability can be expected, and if it exceeds 0.7, the content of trivalent chromium will become extremely high, and on the contrary, corrosion resistance will deteriorate. This is because it decreases. The plated steel plate to be treated in the present invention is a plated steel plate in which a steel plate is subjected to hot-dip plating or electroplating with zinc aluminum, etc.
In addition to galvanized steel plates that are simply plated with zinc, galvanized steel plates that are further heated at high temperatures and alloyed after galvanization are also used (in the present invention, each steel plate to be treated is (collectively called "metsuki steel sheet"). The method for surface-treating such a plated steel plate with the treatment liquid used in the present invention is according to a commonly practiced method. After degreasing the plated steel plate as necessary and cleaning the surface by washing with water, the plated steel plate is subjected to a dipping method, a spraying method, etc. The treatment liquid is applied to the surface of the steel plate by a method such as a method, a roll coater method, a roll drawing method, or an air knife drawing method. Drying is sufficient to evaporate moisture, and the plate temperature is preferably 70 to 100°C. When a silane coupling agent is used as a reducing agent, it is possible to obtain a number of excellent performances that cannot be obtained with conventional reducing agents. The first consideration of such performance is the stability of the processing bath. In general, chromate treatment solutions containing trivalent chromium tend to form precipitates or gel when the pH exceeds 3. However, when a silane coupling agent is used as a reducing agent, the pH is
Even if it is around 5.0, there is no problem with the stability of the liquid. The second feature is the corrosion resistance of plated steel sheets.
It also has excellent workability. This is because the silanol groups generated through hydrolysis, which is the original function of the silane coupling agent, are adsorbed onto the metal surface and also undergo chemical reactions such as crosslinking reactions with CrO 4 - , Cr(OH) 3 , etc. It is thought that this causes the formation of a strong chromate film. On the other hand, since the silane coupling agent also has an organic functional group, it has excellent adhesion to coatings such as alkyd, acrylic, and epoxy paints. The chromate treatment method of the present invention significantly improves the corrosion resistance, workability, and coating adhesion of the plated steel sheet treated with it, and since the chromate treatment method of the present invention is a coating type, it requires no treatment liquid. This combination of the fact that there is no aging and therefore no need for waste liquid treatment makes it extremely valuable industrially. The present invention will be further explained below with reference to Examples and Comparative Examples. EXAMPLE A chromate treatment solution according to the method of the present invention was applied to the surface of various metal-plated steel plates and dried with hot air to obtain chromate-treated steel plates. Types of galvanized steel sheets, treatment liquid adjustment method and its composition, PH, coating method, treatment method, film amount (chromium adhesion amount), drying temperature (plate temperature)
The detailed conditions are shown in Table 1.
【表】【table】
【表】【table】
【表】
この第１表に示す条件によつて得られたクロメ
ート処理鋼板より試験片を採取し、性能評価とし
て平面部、加工部としてエリクセン部、折曲部の
各部についての耐塩水噴霧性を、また塗膜密着性
としてはゴバン目試験、デユポン衝撃試験、エリ
クセン押出試験よる試験を行なつた。その試験結
果を第２表に示す。[Table] Test specimens were taken from the chromate-treated steel sheets obtained under the conditions shown in Table 1, and the salt water spray resistance of the flat section, the Erichsen section as the processed section, and the bent section was evaluated for performance evaluation. In addition, as for the adhesion of the coating film, tests were carried out using a goblin test, a Dupont impact test, and an Erichsen extrusion test. The test results are shown in Table 2.
【表】【table】
【表】
各試験の試験方法は次の通りである。
耐塩水噴霧性の試験はJIS Ｚ 2371（塩水噴霧
試験方法）に準拠し塩水噴霧試験後に白錆発生し
ないものを◎印、10％未満の発生は〇印、10％以
上30％未満のものを△印、30％以上のものを×印
とした。
即ちシランカツプリング剤を用いない比較例１
〜５、無水クロム酸濃度が高過ぎる比較例６、
Cr+3／Cr+6の比が本発明の規定範囲外である比較
例７〜12は何れも本発明の実施例に比し劣つてい
ることが判る。
平面部：平板な試験片をその儘試験に供し、塩水
噴霧試験160時間後で評価した。
エリクセン押出部：エリクセン押出試験により試
験片を４mm押出したものを試験に供し、塩水噴
霧試験120時間後で評価した。
折曲部：180℃折曲げた試験片を試験に供し、塩
水噴霧試験48時間後で評価した。
塗膜密着性の試験はアクリル系塗料を使用し
200℃で約２分間乾燥した塗装試験片について次
の様に各項目の試験を行なつた。
ゴバン目試験：塗装試験片に対し１mm平方のマス
目を鋼素地に達する様にカツターで切り込み、
セロハンテープを貼り付けて急速に引き剥が
し、塗装面の異常の程度を観察した。
デユポン衝撃試験：直径12.7mm（1/2インチ）、重
さ１Kgの重錘を50cmの高さから落下させ、セロ
ハンテープを貼り付け急速に剥がし、塗装面の
異常の程度を観察した。
エリクセン押出試験：エリクセン押出機により塗
装試験片を６mm押出し、セロハンテープを貼り
付け急速に剥がし、塗装面の異常の程度を観察
した。
上記各項目の塗膜密着性は塗膜の剥離程度によ
つて次の４段階に分けて表示した。
◎：塗膜剥離なし
〇：塗膜剥離10％未満
△：塗膜剥離10％以上30％未満
×：塗膜剥離30％以上
第２表に示すようにシランカツプリング剤で還
元されたクロメート処理液で表面処理を行なう本
発明の実施例１〜８のクロメート処理方法による
場合は、比較例１〜10のクロメート処理液を用い
る場合に較べて形成されるクロメート皮膜は平面
部における耐食性が優れていることは勿論の事、
エクセリン押出部や折曲部における耐食性も優れ
ており、クロメート皮膜が被処理板に極めて強固
に密着しているものであり、従つてまた加工性が
優れていることが判つた。また塗料の密着性につ
いてもゴバン目、デユポン衝撃、エリクセン押出
各試験共に本発明例は比較例に較べて優れている
ことが判つた。
またシランカツプリング剤で還元されたクロメ
ート処理液はPH5.0程度でも何等液の安定性に問
題なく、従来のクロメート処理浴の管理に比べて
非常に管理し易い浴に改善されている。[Table] The test method for each test is as follows. The salt spray resistance test is based on JIS Z 2371 (salt spray test method), and those that do not generate white rust after the salt spray test are marked with ◎, those with less than 10% are marked with ○, and those with 10% or more and less than 30% are marked with ◎. △ marked, and those with 30% or more were marked ×. That is, Comparative Example 1 without using a silane coupling agent.
~5, Comparative example 6 where the concentration of chromic anhydride is too high,
It can be seen that all of Comparative Examples 7 to 12, in which the ratio of Cr +3 /Cr +6 was outside the specified range of the present invention, were inferior to the Examples of the present invention. Flat part: A flat test piece was subjected to a permanent test, and evaluated after 160 hours of salt spray test. Erichsen extrusion part: A 4 mm test piece was extruded according to the Erichsen extrusion test and evaluated after 120 hours of the salt spray test. Bent part: A test piece bent at 180°C was subjected to the test, and evaluated after 48 hours of salt spray test. The paint film adhesion test uses acrylic paint.
The following tests were conducted on painted test pieces that had been dried at 200°C for about 2 minutes. Goban test: Cut 1 mm square squares into the painted test piece with a cutter to reach the steel base.
Cellophane tape was applied and rapidly peeled off to observe the degree of abnormality on the painted surface. Dupont impact test: A weight with a diameter of 12.7 mm (1/2 inch) and a weight of 1 kg was dropped from a height of 50 cm, and cellophane tape was applied and rapidly peeled off to observe the degree of abnormality on the painted surface. Erichsen extrusion test: A painted test piece was extruded by 6 mm using an Erichsen extruder, cellophane tape was applied and quickly peeled off, and the degree of abnormality on the painted surface was observed. The coating adhesion of each of the above items was classified into the following four levels depending on the degree of peeling of the coating. ◎: No paint film peeling 〇: Paint film peeling less than 10% △: Paint film peeling 10% or more and less than 30% ×: Paint film peeling 30% or more Chromate treatment reduced with a silane coupling agent as shown in Table 2 When using the chromate treatment methods of Examples 1 to 8 of the present invention, in which surface treatment is carried out with a liquid, the chromate film formed has superior corrosion resistance on flat surfaces compared to the case where the chromate treatment liquids of Comparative Examples 1 to 10 are used. Of course there are,
It was found that the corrosion resistance at the extruded portions and bent portions of Excelin was excellent, and the chromate film adhered extremely firmly to the plate to be treated, and therefore, the workability was also excellent. It was also found that the inventive examples were superior to the comparative examples in terms of paint adhesion in the goblin, Dupont impact, and Erichsen extrusion tests. Furthermore, the chromate treatment solution reduced with the silane coupling agent has no problem with the stability of the solution even at a pH of around 5.0, and is much easier to manage than conventional chromate treatment baths.
Claims (1)
リング剤を添加して無水クロム酸の一部を還元さ
せて得られた液の組成を無水クロム酸0.1〜
1mol／、３価クロムと６価クロムとのモル比
（Cr+3／Cr+6）を0.05〜0.7とした処理液でメツキ
鋼板を表面処理することを特徴とするメツキ鋼板
のクロメート処理方法。 ２ 表面処理を施すメツキ鋼板として亜鉛メツキ
を施した亜鉛メツキ鋼板を用いる特許請求の範囲
第１項に記載のメツキ鋼板のクロメート処理方
法。 ３ 表面処理を施すメツキ鋼板として亜鉛メツキ
を施した後に更に高温加熱して合金化処理を施し
た亜鉛メツキ鋼板を用いる特許請求の範囲第１項
に記載のメツキ鋼板のクロメート処理方法。 ４ 表面処理を施すメツキ鋼板としてアルミニウ
ムメツキを施したアルミニウムメツキ鋼板を用い
る特許請求の範囲第１項に記載のメツキ鋼板のク
ロメート処理方法。 ５ 表面処理を施されるメツキ鋼板がそのメツキ
を溶融メツキによりなされたものである特許請求
の範囲第１項ないし第４項のうちの何れか１項に
記載のメツキ鋼板のクロメート処理方法。 ６ 表面処理を施されるメツキ鋼板がそのメツキ
を電気メツキによりなされたものである特許請求
の範囲第１項ないしは第４項のうちの何れか１項
に記載のメツキ鋼板のクロメート処理方法。[Claims] 1. A silane coupling agent is added to a chromic anhydride (CrO 3 ) solution to reduce a part of the chromic anhydride.
A chromate treatment method for a galvanized steel sheet, comprising surface-treating the galvanized steel sheet with a treatment solution having a molar ratio of trivalent chromium to hexavalent chromium (Cr +3 /Cr +6 ) of 0.05 to 0.7. 2. The method for chromate treatment of a galvanized steel sheet according to claim 1, which uses a galvanized steel sheet that has been subjected to galvanization as the galvanized steel sheet to which the surface treatment is applied. 3. The method for chromate treatment of a galvanized steel sheet according to claim 1, which uses a galvanized steel sheet that is subjected to galvanization and then further heated at a high temperature to undergo alloying treatment as the surface-treated galvanized steel sheet. 4. The method for chromate treatment of a plated steel plate according to claim 1, which uses an aluminum plated steel plate that has been subjected to aluminum plating as the plated steel plate to which the surface treatment is applied. 5. The method for chromate treatment of a plated steel plate according to any one of claims 1 to 4, wherein the plated steel plate to be surface-treated is plated by hot-dip plating. 6. The method for chromate treatment of a plated steel plate according to any one of claims 1 to 4, wherein the plated steel plate to be surface-treated is plated by electroplating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12068781A JPS5822383A (en) | 1981-08-03 | 1981-08-03 | Chromate treatment of plated steel plate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12068781A JPS5822383A (en) | 1981-08-03 | 1981-08-03 | Chromate treatment of plated steel plate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5822383A JPS5822383A (en) | 1983-02-09 |
| JPS6335712B2 true JPS6335712B2 (en) | 1988-07-15 |
Family
ID=14792462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12068781A Granted JPS5822383A (en) | 1981-08-03 | 1981-08-03 | Chromate treatment of plated steel plate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5822383A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08982B2 (en) * | 1986-02-28 | 1996-01-10 | 日本パ−カライジング株式会社 | Metal chromating method |
| JPS62202084A (en) * | 1986-02-28 | 1987-09-05 | Nippon Parkerizing Co Ltd | Treatment of surface of metal |
| JPH0781193B2 (en) * | 1988-07-08 | 1995-08-30 | 株式会社日本ダクロシャムロック | Metal surface treatment method |
| JPH03243796A (en) * | 1990-02-22 | 1991-10-30 | Nippon Steel Corp | Production of organic compositely plated steel sheet having high corrosion resistance |
| JPH0696778B2 (en) * | 1990-10-05 | 1994-11-30 | 新日本製鐵株式会社 | Chromate treatment method for galvanized steel sheet |
| JP2628782B2 (en) * | 1990-10-08 | 1997-07-09 | 日本パーカライジング株式会社 | Chromate treatment method for galvanized steel sheet |
| JPH0753913B2 (en) * | 1990-11-14 | 1995-06-07 | 新日本製鐵株式会社 | Method for manufacturing organic composite plated steel sheet |
| JP3278509B2 (en) * | 1993-10-21 | 2002-04-30 | 日本パーカライジング株式会社 | Method for forming hardly soluble chromate film on zinc-containing metal plated steel sheet |
| US6149735A (en) * | 1995-11-30 | 2000-11-21 | Henkel Corporation | Chromate treatment bath composition and process for application to metals |
| WO2005087981A1 (en) * | 2004-03-10 | 2005-09-22 | Jfe Steel Corporation | Steel sheet for fuel tank and method for manufacture thereof |
-
1981
- 1981-08-03 JP JP12068781A patent/JPS5822383A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5822383A (en) | 1983-02-09 |
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