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

A thermosetting resin composition which comprises:

• 2-50 parts of an acrylic polyol resin (VII-A) containing a the hydroxyalkyl(meth)acrylate composition comprising
• 0.3 to less than 1.0 mole of polymerized lactone monomer being polymerized by ring-opening with respect to 1 mole of hydroxyalkyl(meth)acrylate, wherein the content of the lactone monomer in the hydroxyalkyl(meth)acrylate composition is 0-10% by weight, and
• a proportion of monomers having two or more Continuous chains (n≧2) of lactones less than 37.4% (area by GPC),
• the hydroxyalkyl(meth)acrylate composition being represented by formula (1) described below,
• where
• 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 an integer greater than or equal to zero, and
• an average value of “n” in the hydroxyalkyl(meth)acrylate composition is not less than 0.3 to less than 1.0,
• and 30-80 parts of an acrylic copolymer (VII-B) having an alkoxylsilyl group, wherein the total of (VII-A) and (VII-B) is 100 parts by weight.

A method for the preparation of a carboxylic group-containing acrylate composition (a′) represented by a general formula (VIII-3) described below, said method comprising:

• reacting a hydroxyalkyl(meth)acrylate composition, said hydroxyalkyl(meth)acrylate composition comprising 0.3 to less than 1.0 mole of polymerized lactone monomer being polymerized by ring-opening with respect to 1 mole of hydroxyalkyl(meth)acrylate, wherein the content of the lactone monomer in the composition is 0-10% by weight, and
• a proportion of monomers having two or more continuous chains (n≧2) of lactones less than 37.4% (area by GPC),
• the composition being represented by formula (1) described below,
• where
• R, R1, R2, and R3 are independently a hydrogen or a methyl group,
• “j” is an integer of 2-6,
• xn nieces 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 an integer greater than or equal to zero, and
• an average value of “n” in the composition is not less than 0.3 to less than 1.0, with a carboxylic acid or anhydride thereof (VIII-b) represented by a general formula (VIII-2) described below,
• (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 an integer greater than or equal to zero, an average value of “n” in said composition is not less than 0.3 to less than 1.0, R9 is a residual group of a carboxylic acid, and “m” is an integer of 1-3).