聚氨酯中多元醇的羟基数目

Polyurethane has an excellent flexibility, adhesiveness and high impregnation rate, widely utilized such as automotive films, insulating materials, and paints. The polyurethane resin is a polymer which involves the urethane bond, obtained by the polymerization reaction between polyisocyanate and polyol (also called, polyester or polyether). ･･･ ―NCO + HO― ･･ 􀃆 ･･ ―NHCOO― ･･･ (1) There are several different test methods for measuring hydroxyl groups (-OH) of polyols. In this application note, the test method using pyridine solution containing phthalic anhydride is applied to the polyol sample. The hydroxyl number is expressed as milligrams (mg) of potassium hydroxide as equilibrium amount of hydroxide groups contained in 1g of sample.