COATING COMPOSITION, LAMINATE POLYESTER FILM, AND SOLAR CELL BACK SHEET

摘要

PROBLEM TO BE SOLVED: To provide a coating agent for a polyester film which is to be used for a solar cell back sheet and shows good adhesiveness after an endurance test.SOLUTION: A coating composition is provided, which comprises: a hydroxyl group-containing acrylic resin (I) obtained by copolymerizing a hydroxyl group-containing acrylic monomer and acrylic monomers that give an acrylic resin having an SP value of 7.0 to 9.0 (cal/mL), as essential components; and a polyisocyanate compound (II). Also disclosed are: a laminate polyester film having a cured film 1 of the above coating composition laminated on a polyester resin film 2; and a solar cell back sheet having a multilayer structure including the above laminate polyester film. The acrylic resin has a hydroxyl value of 1 to 200 mgKOH/g and a weight average molecular weight of 5000 to 500000; and an equivalent ratio [(b)/(a)] of isocyanate groups (b) in the isocyanate compound to hydroxyl groups (a) in the acrylic resin ranges from 0.5 to 5.0.