Lowly lactone-modified reactive monomer composition, acrylic polyol resins produced with the same, curable resin compositions and coating compositions

A method for the preparation of a hydroxyalkyl (meth)acrylate composition modified by a small amount of lactones wherein a proportion of monomers having not less than 2 continuous chains (n≧2) of lactones is less than 50% by mol (GPC area %), characterized in that a hydroxyalkyl(meth)acrylate is allowed to react with a lactone in a reaction molar ratio of more than 1 in the case of preparing the polylactone-modified hydroxyalkyl (meth)acrylate through allowing to react the hydroxyalkyl(meth)acrylate with a lactone monomer by ring-opening polymerization according to a reaction represented by a general formula (2) described below,

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• (in the formula, R, R1, R2, and R3 are independently a hydrogen or a methyl group, “j” is an integer of 2-6, xn pieces of R4 and R5 are independently a hydrogen or an alkyl group having a carbon number of 1-12, “x” is 4-7, “n” is 0 or an integer of not less than 1, and an average value of “n” in a composition is not less than 0.3 to less than 1.0).

A melamine-curable type water-based coating composition comprising 5-30 parts by weight of an acrylic polyol resin (A) obtained using a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones represented by the above-described general formula (1) as claimed in claim, wherein a proportion of monomers having not less than 2 continuous chains (n≧2) of lactones is less than 50% (GPC area %), as polymerizing components, and 10-60 parts by weight of an amino-plasto resin (IV-B).

A coating characterized by containing (i) crosslinked particles obtained by dispersing a mixture of an acrylic polyol resin (VI-A) with a polyisocyanate compound (VI-B) into a water-based medium and by crosslinking thereof, or (ii) composite-type crosslinked particles composed of a urethane-urea/ethylene-based resin obtained through polymerizing polymerizable ethylenic unsaturated compounds containing a hydroxyalkyl(meth)acrylate composition (a) modified by a small amount of lactones in water in which crosslinked urethane-urea particles are dispersed, as resin components for forming a thin layer.

A polyester unsaturated monomer composition modified by a small amount of lactones, in which a proportion of monomers having not less than 2 continuous chains (n≧2) of lactones is less than 50% (GPC area %), which is obtained by a ring-opening polymerization of a lactone monomer with respect to a polymerizable unsaturated monomer containing carboxylic group.

A method for the preparation of a polyester unsaturated monomer composition modified by a small amount of lactone, wherein 0.3-less than 1.0 mol of a lactone monomer is polymerized by ring-opening with respect to 1 mol of a radically polymerizable unsaturated monomers containing carboxylic group, whereby, a proportion of monomers having not less than 2 continuous chains (n≧2) of lactones is adjusted to less than 50% (GPC area %).

A method for the preparation of a polyester unsaturated monomer composition modified by a small amount of lactone, characterized in that 0.3-less than 1.0 mol of a lactone monomer is polymerized by ring-opening with respect to 1 mol of a radically polymerizable unsaturated monomer containing carboxylic group using a stannous halide, monobutyltin tris-2-ethylhexanate, stannous octoate, dibutyltin dilaurate, or a mixture thereof as a catalyst, followed by separating the unreacted radically polymerizable unsaturated monomer containing carboxylic group.