EP0757726A1 - Procede de pretraitement de substrats metalliques avant application de peinture - Google Patents

Procede de pretraitement de substrats metalliques avant application de peinture

Info

Publication number
EP0757726A1
EP0757726A1 EP95915597A EP95915597A EP0757726A1 EP 0757726 A1 EP0757726 A1 EP 0757726A1 EP 95915597 A EP95915597 A EP 95915597A EP 95915597 A EP95915597 A EP 95915597A EP 0757726 A1 EP0757726 A1 EP 0757726A1
Authority
EP
European Patent Office
Prior art keywords
treatment
painting
copper
ions
zinc phosphate
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.)
Withdrawn
Application number
EP95915597A
Other languages
German (de)
English (en)
Other versions
EP0757726A4 (fr
Inventor
Hitoshi A-203 COPO-ATOU ISHII
Yasuhiko Nagashima
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Henkel Corp
Original Assignee
Henkel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Henkel Corp filed Critical Henkel Corp
Publication of EP0757726A1 publication Critical patent/EP0757726A1/fr
Publication of EP0757726A4 publication Critical patent/EP0757726A4/fr
Withdrawn legal-status Critical Current

Links

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
    • C23C22/82—After-treatment
    • C23C22/83—Chemical after-treatment

Definitions

  • This invention concerns a method of pre-treating various metal substrates, for example steel, steel sheet, zinc based plated steel sheet and aluminum and its alloys.
  • the invention concerns a method of pre-treat- ing metal substrates prior to painting which provides excellent paint film adhesion in those cases where painting is carried out with a cationic electrodeposition type paint, for example.
  • phosphate based conversion coating forming liquid compositions and chromate treatments are generally used as methods of pre- treating various metal substrates prior to painting.
  • the zinc phosphate based conversion coating forming liquid compositions are advantage ⁇ ous when compared with the chromate treatments, which involve environmentally harmful hexavalent chromium, in that they have excellent effluent treatment properties, and in that various metal substrates, such as cold-rolled steel sheet and zinc based plated steel sheet for example, can be treated at the same time, and these methods are widely used as pre-treatments prior to the painting of automobile bodies and domestic electrical appliances.
  • the adhesion between the paint film and the base metal can be cited as typical indi ⁇ cators of performance required when a metal substrate is painted.
  • a metal substrate is painted, it is possible to improve the aforementioned aspects of painting performance by subjecting the metal to a zinc phosphate based conver- sion coating forming liquid composition as a pre-treatment prior to painting.
  • Fur ⁇ thermore even in systems where painting is carried out after a zinc phosphate based conversion coating is in place, the painting performance can be further im ⁇ proved by improving the surface characteristics of the zinc phosphate based con ⁇ version coating itself.
  • a zinc phosphate based conversion coating is comprised in the main of zinc phosphate crystals (hopeite) but, on iron and steel materials, the iron com ⁇ ponent which is dissolved out from the base is taken into the film and co-precipi ⁇ tated in part as zinc iron phosphate crystals (phosphophilite).
  • Zinc iron phos ⁇ phate crystals are chemically stable when compared with zinc phosphate crys- tals, i.e., they have better resistance to dissolution by acids and alkalies, so that the painting performance can be improved by increasing the co-precipitation rate of zinc iron phosphate crystals.
  • This present invention resolves these problems of the prior art and pro ⁇ vides a method of pre-treating metal substrate prior to painting with which it is possible to reduce the costs, with low polluting characteristics, and to obtain ade ⁇ quate painting performance (adhesion of the paint film, corrosion resistance after painting) in cases where the improving effect of the film is inadequate and in cases where it is not possible to use a chromate treatment or resin based treat ⁇ ment as an after-treatment, without adding components for improving the film properties, such as nickel ions, to the zinc phosphate based conversion coating forming liquid compositions.
  • this present invention provides a method of pre-treating metal substrates prior to painting, characterized in that the surface of the metal substrate, following treatment with a zinc phosphate based conversion coating forming liquid composition, is brought into contact with an aqueous solution con ⁇ taining 2 - 200 parts per million by weight (hereinafter usually abbreviated "ppm") of copper(ll) cations at pH 4 - 6. Moreover, the preferred temperature conditions of the said aqueous solution are 20 - 45 ° C.
  • the metal substrate which is treated in this present invention is, in the main, steel, steel sheet, zinc based plated steel sheet or aluminum alloy, but it is not limited to these materials.
  • the aqueous solution which is used in the treatment of this present inven ⁇ tion (referred to below as the treatment liquid) is an aqueous solution containing copper(ll) cations at a concentration of 2 - 200 ppm, along with some counterions for the copper ions. If the copper ions concentration is less than 2 ppm, then an adequate painting performance usually is not obtained, and if the copper ions concentration exceeds 200 ppm, then not only does the corrosion resistance after painting generally deteriorate but undesirable corrosion of the apparatus is also accelerated.
  • the preferable concentration of copper ions is 5 - 50 ppm. No particular limitation is imposed upon the source of supply of the copper ions, and they can be added in the form of a salt, such as copper sulfate, copper nitrate, copper phosphate or copper chloride for example.
  • the pH of the treatment liquid should be from 4 -6. In those cases where it is less than pH 4, the zinc phosphate based chemically formed film which has been produced earlier is often dissolved away completely, and, conversely, in those cases where the pH exceeds 6, the copper ions are usually precipitated as hydroxide.
  • acid components such as nitric acid, sulfuric acid, phos ⁇ phoric acid, and hydrochloric acid for example, or alkaline components, such as sodium hydroxide, sodium carbonate, and aqueous ammonia for example, can be used to adjust the pH of the treatment liquid.
  • the temperature of the treatment liquid is preferably 20 - 45
  • the fundamental zinc phosphate based conversion coating process for a metal substrate generally involves an alkaline degreasing, a first water rinse, treating with a zinc phosphate based conversion coating forming liquid composi ⁇ tion, a second water rinse, and a rinse with deionized water.
  • the phrase "following the zinc phosphate based conversion coating" in this description of the present invention signifies a process step between treatment with the zinc phos ⁇ phate based conversion coating forming liquid composition and the rinse with de ⁇ ionized water.
  • the after treatment with a solution containing copper ions according to this invention preferably is carried out between treat- ment with a zinc phosphate based conversion coating forming liquid composition and the second water rinse or between the second water rinse and the rinse with deionized water, and at least one treatment with a solution containing copper ions is necessary.
  • each process step as described above may be a multi-stage treatment, and a surface activation process with an activating agent of the titanium colloid type, as is well known in the zinc phos- phating art, usually is preferably included as a process step prior to the treatment with a zinc phosphate based conversion coating forming liquid composition, with a view to providing finer crystals in the phosphate coating formed.
  • a treatment time i.e., time of contact between the liquid treatment compositions and the metal substrates, of 10 - 120 seconds is preferred.
  • Known liquid zinc phosphate based conversion coating forming liquid compositions can be used for the treatment liquid in the zinc phosphate based conversion coating forming process.
  • a treatment liquid which contains zinc ions and phosphate ions as the main components, at least one species selected from among nitrate ion, nitrite ion and chlorate ion as an oxidizing agent, and sodium ions for example as neutral ions, can be used.
  • additional metal ions such as nickel ion and manganese ion for example, and fluoride, for example, as an etching agent, may advantageously be added to the zinc phos ⁇ phate based conversion coating forming liquid compositions, with a view to im- proving painting performance, as is generally known in the art.
  • the adhesion of the paint film is determined by the strength of adhesion at the in ⁇ terface between the zinc phosphate based conversion coating thereby formed and the paint film.
  • the strength of adhesion of the paint film can be in ⁇ creased by improving the zinc phosphate conversion coating surface to a surface condition with which the strength of adhesion with an organic paint film is strong ⁇ er. If the adhesion of the paint film is improved, then the progress of corrosion is also suppressed, so that an improvement of corrosion resistance can also be expected.
  • the method of treatment according to this present invention is aimed at improving the zinc phosphate based conversion coating surface, and it is thought that a surface state which provides good adhesion with an organic paint film is achieved by covering the film surface with a copper compound such as copper phosphate.
  • base metals such as iron, zinc and aluminum are less noble metals than copper, and if these metal substrates are brought into contact with an aqueous solution containing copper ions, some metallic copper is almost al ⁇ ways deposited on the base metal, because baser metals normally spontaneous- ly dissolve in the presence of ions of nobler metals that can be deposited, in amounts corresponding to the amount of nobler metal deposited.
  • Metallic cop ⁇ per deposited in this way can result in a deterioration of corrosion resistance, by way of a local electrical cell action with the base metal.
  • Rectangular cold-rolled steel (“CRS”) sheets 70 millimeters (hereinafter usually abbreviated “mm”) wide x 150 mm long and 0.8 mm thick (type SPCC- SD), electrogalvanized (“EG”) steel sheets (zinc coating: 20 grams/meter 2 ) and aluminum alloy (“AA”) sheets (type JIS-A5052) were used, and these were sub ⁇ jected to treatment using the treatment processes described below. Also, the paint film adhesion and corrosion resistance were evaluated with test sheets which had been processed through the final painting, Treatment Process Steps and Conditions
  • Zinc phosphate based conversion coating A nickel-free treatment liquid consisting of water and: zinc ions, 1.3 grams per liter (hereinafter usually abbreviated "g/l"); manganese ions: 0.5 g/l; phosphate ions, 15 g/l; nitrate ions, 7 g/l; fluosilicate ions, 1.0 g/l; nitrite ions in an amount to yield 3
  • points of accelerant as measured by the saccharometer method; free acid points, i.e., the number of milliliters (hereinafter usually abbreviated "ml") of 0.1 N sodium hydroxide needed to titrate 10 ml of treatment liquid with bromophenol blue as indicator, 0.9; temperature, 43° C; contact time, 120 seconds; contact method, dipping.
  • ml milliliters
  • Water rinse Deionized water (electrical conductivity less than 0.2 ⁇ S/cm), ambient temperature, 20 seconds, spray.
  • Comparative Examples 1 - 6 in which either the cop ⁇ per ion concentration of the treatment liquid or the pH of the treatment liquid was outside the range of this invention, did not have adequate painting performance. With Comparative Examples 1 and 2 in particular, where the copper ion concen ⁇ tration exceeded the upper limit value, the paint film adhesion was good but there was a clear and pronounced deterioration in corrosion resistance, believed to be due to the excessive deposition of metallic copper. (3) Moreover, Comparative Examples 7 and 8 are controls in which the after- treatment following the zinc phosphate based conversion coating was omitted.
  • the method of pre-treatment prior to painting of this present invention is characterized by treatment with a dilute solution of copper ions as an after-treat ⁇ ment following a zinc phosphate based conversion coating, and, in comparison with conventional after-treatments which have been used in practice, there are improvements in terms of waste water treatment and chemical costs, and the in ⁇ vention can be carried out even with the conventional water rinsing process and with little limitation in terms of processing.

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)

Abstract

On met en contact une surface de substrat métallique revêtue par conversion de phosphate de zinc avec une solution aqueuse possédant un pH compris entre 4 et 6 et contenant de 2 à 200 ppm de cations cuivreux afin d'améliorer l'adhésion de la peinture, appliquée ensuite de manière cathodique.
EP95915597A 1994-04-12 1995-04-12 Procede de pretraitement de substrats metalliques avant application de peinture Withdrawn EP0757726A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP6098249A JPH07278891A (ja) 1994-04-12 1994-04-12 金属材料の塗装前処理方法
JP98249/94 1994-04-12
PCT/US1995/004303 WO1995027809A1 (fr) 1994-04-12 1995-04-12 Procede de pretraitement de substrats metalliques avant application de peinture

Publications (2)

Publication Number Publication Date
EP0757726A1 true EP0757726A1 (fr) 1997-02-12
EP0757726A4 EP0757726A4 (fr) 1997-04-09

Family

ID=14214689

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95915597A Withdrawn EP0757726A4 (fr) 1994-04-12 1995-04-12 Procede de pretraitement de substrats metalliques avant application de peinture

Country Status (4)

Country Link
EP (1) EP0757726A4 (fr)
JP (1) JPH07278891A (fr)
WO (1) WO1995027809A1 (fr)
ZA (1) ZA953033B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2329755A (en) * 1997-09-26 1999-03-31 Samsung Display Devices Co Ltd A method of preparing a positive electrode for nickel-based battery and a slurry composition for the same

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19511573A1 (de) * 1995-03-29 1996-10-02 Henkel Kgaa Verfahren zur Phosphatierung mit metallhaltiger Nachspülung
DE19606018A1 (de) * 1996-02-19 1997-08-21 Henkel Kgaa Zinkphosphatierung mit geringen Gehalten an Nickel- und/oder Cobalt
DE19606017A1 (de) * 1996-02-19 1997-08-21 Henkel Kgaa Zinkphosphatierung mit geringen Gehalten an Kupfer und Mangan
DE19956383A1 (de) * 1999-11-24 2001-05-31 Henkel Kgaa Verfahren zur Phospatierung mit metallhaltiger Nachspülung
JP3778791B2 (ja) * 2000-11-07 2006-05-24 マツダ株式会社 塗装前処理方法及び成形物
US8282801B2 (en) 2008-12-18 2012-10-09 Ppg Industries Ohio, Inc. Methods for passivating a metal substrate and related coated metal substrates
ES2873381T3 (es) * 2015-04-07 2021-11-03 Chemetall Gmbh Procedimiento para el ajuste específico de la conductividad eléctrica de revestimientos de conversión
CN106350856A (zh) * 2016-09-11 2017-01-25 经阁铝业科技股份有限公司 一种铝型材阳极电泳表面处理工艺
CN108456878B (zh) * 2018-03-08 2019-07-16 东北大学 一种纳米颗粒表面改性提升转化膜性能方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3579429A (en) * 1967-04-14 1971-05-18 Amchem Prod Process for applying a white paint electrophoretically
EP0149720A2 (fr) * 1984-01-07 1985-07-31 Gerhard Collardin GmbH Procédé de post passivation de surfaces métalliques phosphatées, utilisant des solutions contenant des cations de titane et/ou manganèse et/ou cobalt et/ou nickel et/ou cuivre

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4897129A (en) * 1986-05-12 1990-01-30 The Lea Manufacturing Company Corrosion resistant coating

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3579429A (en) * 1967-04-14 1971-05-18 Amchem Prod Process for applying a white paint electrophoretically
EP0149720A2 (fr) * 1984-01-07 1985-07-31 Gerhard Collardin GmbH Procédé de post passivation de surfaces métalliques phosphatées, utilisant des solutions contenant des cations de titane et/ou manganèse et/ou cobalt et/ou nickel et/ou cuivre

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9527809A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2329755A (en) * 1997-09-26 1999-03-31 Samsung Display Devices Co Ltd A method of preparing a positive electrode for nickel-based battery and a slurry composition for the same

Also Published As

Publication number Publication date
ZA953033B (en) 1995-12-21
WO1995027809A1 (fr) 1995-10-19
EP0757726A4 (fr) 1997-04-09
JPH07278891A (ja) 1995-10-24

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