Surface treatment agent for metal, surface treatment method for metallic material, and surface-treated metallic material

Abstract

An agent for treating metal surfaces which comprises an aqueous medium and, incorporated therein, (A) a cationic urethane resin which is water-soluble or in an aqueous emulsion form, (B) a cationic polycondensation product obtained from a phenol compound and an aldehyde, and (C) a zirconium compound and / or titanium compound. A coating film formed from the treating agent imparts excellent corrosion resistance and alkali resistance to a metallic material. When the proportion of the urethane resin (A) is equal to or higher than that of the polycondensation product (B), yellowing resistance can be also imparted. By incorporating a metal compound (D) containing a specific metal, excellent blacking resistance also can be imparted. Furthermore, by incorporating an acid ingredient (E) and a vanadium compound (F), a further improvement in performances can be attained.

Description

technical field [0001] The present invention relates to a metal surface treatment agent, a metal surface treatment method and a surface treatment metal material, which are used to form a metal coil and a formed product surface with excellent corrosion resistance and alkali resistance, and In some cases, excellent blackening resistance and excellent yellowing resistance can also be provided, and a coating film not containing chromium can be provided. More specifically, the present invention relates to a surface treatment agent, a surface treatment method, and a surface-treated metal material, which are used in automobile bodies, automobiles, etc. Formed products such as parts, building materials, and home appliance parts, castings, coils, etc., can be given excellent corrosion resistance, alkali resistance, and depending on the situation, excellent blackening resistance and yellowing resistance, and form The most important is the chromium-free coating. Background technique ...

AI Technical Summary

Problems solved by technology

[0005] However, these metal surface treatment methods that do not use chromium, in contrast to the advantage that the treatment solution does not contain hexavalent chromium, its corrosion resistance is not good enough, especially the corrosion resistance of scars and processed parts is obviously lower than that of Poor chromate coating

Furthermore, there is a disadvantage that the anti-blackening property is insufficient in a high-temperature and high-humidity environment.

What's more, generally speaking, the resin film has the characteristic of turning yellow or brown under the influence of heat (yellowing property), so it has the disadvantage of discoloration due to the influence of heat generated during welding and punching.

Therefore, the current situation is that there is no chromium-free metal surface treatment that can form a film on the surface of a metal material that has excellent corrosion resistance, alkali resistance, and blackening resistance, and can further have excellent yellowing resistance in some cases. agent

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