Metal surface treating agents, their preparation, use in treating steel materials, coated steel materials and their production

摘要

A chromate-free metal surface treating agent which is well adapted for use with a metal-coated steel material is provided. This agent provides excellent workability, adhesion, and corrosion resistance when used as a pretreatment before providing an overcoat, for example, by applying a coating composition. A steel material which has been treated with such surface treating agent, and a method for treating a metal surface with such surface treating agent, as well as a coated steel material having an overcoat formed on the surface treated steel material, and its production method are also provided. The metal surface treating agent contains a compound which contains all of the following structures (a) to (c): (a) a straight chain and/or branched organic polymer skeleton formed by carbon - carbon bond optionally containing nitrogen atom between the carbon - carbon bond; (b) a primary, secondary, or tertiary amino group; and (c) a silyl group having a hydrolyzable group and/or hydroxy group bonded by silicon - carbon bond in one molecule and/or its (partial) hydrolysis and condensation product as its critical component, and this critical component is dissolved in water and/or an organic solvent.