METHOD FOR PRODUCING ORGANIC COMPOSITE COATED STEEL SHEET HAVING EXCELLENT SURFACE APPEARANCE

• Main Authors: OGAWA TAKASHI, OKAMOTO KOTARO, MATSUZAKI AKIRA
• Format: Patent
• Language: English
• Published: 15.09.2005
• Edition: 7
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

PROBLEM TO BE SOLVED: To obtain an organic composite coated steel sheet having excellent surface appearance free from unevenness. SOLUTION: When an organic composite coated steel sheet is produced in such a manner that the surface of a galvanized steel sheet or an aluminum based steel sheet is coated with an acid aqueous solution comprising phosphoric acid and/or a phosphoric acid compound by 0.001 to 6.0 mol/L expressed in terms of the quantity of P2O5, comprising oxide particulates by 0.001 to 3.0 mol/L, and comprising one or more of the respective metal ions of Mg, Ca, Sr, Ba, Mn, Al and Fe, water soluble ions containing at least one of the above metals and compounds containing at least one of the above metals by 0.001 to 3.0 mol/L by the total expressed in terms of the quantity of the above metal(s), so as to be dried and heated, thus a phosphoric acid-containing film with a film thickness of 0.005 to 4 μm is formed, and an organic film of 0.1 to 5 μm is formed thereon, the ratio between the quantity α (mol/L) of the phosphoric acid and/or phosphoric compound expressed in terms of P2O5and the quantity β (ppm) of the Zn ions, α/β is controlled to ≥1.7×10-5. COPYRIGHT: (C)2005,JPO&NCIPI