polyurethane adhesive, solar cell protective sheet for adhesive, and the back surface protective sheet for solar cells

摘要

Provided is an adhesive that has favorable adhesive strength for use in the untreated surface material of an untreated polyester film or the like; suppresses a decrease in adhesion strength over time, even in outdoor exposure conditions; and is capable of maintaining adhesion strength over a long period of time. This polyurethane adhesive is a polyurethane adhesive using a main agent and a curing agent, wherein the main agent contains a specific polyester polyol (A), a specific polycarbonate polyurethane polyol (B), and a specific bisphenol type epoxy resin (C) at a specific ratio, and the curing agent contains a specific amount of a polyisocyanate component with an isocyanurate skeleton.