Curable resin composition, paint using the same, and coat-finishing method

A paint comprising as a binder a curable resin composition comprising at least one vinyl polymer and containing all of the following four functional groups:

• (i) a blocked hydroxyl group which is easily cleaved by atmospheric moisture and heat application to form a free hydroxyl group;
• (ii) an epoxy group;
• (iii) an acid anhydride group;
• and
• (iv) a hydrolytic silyl group,
• wherein the blocked hydroxyl group (i) and the epoxy group (ii) are in a single vinyl polymer having a number average molecular weight of not greater than 1,500, or the blocked hydroxyl group (i) and the epoxy group (ii) are respectively in two different vinyl polymers each having a number average molecular weight of not greater than 1,500,
• wherein the acid anhydride group (iii) is in a vinyl polymer having a number average molecular weight of not greater tan 1,500 which may be the same as or different from the vinyl polymer containing at least one of the blocked hydroxyl group (i) and epoxy group (ii), or the acid anhydride group (iii) is in an acid anhydride group-cotaining compound,
• wherein the hydrolytic silyl group (iv) is in a vinyl polymer having a number average molecular weight of not greater than 5,000 which may be the same as or different from the vinyl polymer containing at least one of the blocked hydroxyl group (i), epoxy group (ii) and acid anhydride group (iii), or the hydrolytic silyl group (iv) is in a hydrolytic silyl group-containing compound which may also contain an epoxy group in addition to tile epoxy group (ii) in said vinyl polymer having a number average molecular weight not greater than 1,500;
• and wherein said blocked hydroxyl group has a structure represented by one of the formulas (I), (II) or (III) ##STR9## wherein R.sub.1 and R.sub.2 may be the same or different and is independently a C.sub.1-18 alkyl group, phenyl group, or aryl group, or a hydrogen atom, chlorine atom, or fluorine atoms;
• R.sub.3 is a C.sub.1-18 alkyl group, phenyl group, or aryl group;
• ##STR10## wherein R.sub.4 is a hydrogen atom or a C.sub.1-10 alkyl group;
• and R.sub.5 is a C.sub.1-22 alkyl group with at least one substituent selected from the group consisting of cycloalkyl group, aralkyl group, aryl group, alkoxy group, alkanoyloxy group, C.sub.1-18 alkyl group, and a halogen atom;
• and ##STR11## wherein X is a C.sub.1-18 alkyl group with at least one substituent selected from the group consisting of alkoxy group, aryalkyl group, aryl group, arloxy group, alkanoyloxy group, C.sub.1-10 alkyl group, and a halogen atom.