LOW-HARDNESS POLYURETHANE ELASTOMER FORMING COMPOSITION AND PRESSURE-SENSITIVE ADHESIVE SHEET

PROBLEM TO BE SOLVED: To provide a super-low-hardness elastomer forming composition which has non-bleeding property, is excellent in ruggedness following-up property, has transparency, high strength and high elongation rate and, particularly, is extremely excellent in transparency at an Asker C hardness of 30 or less, and to provide a pressure-sensitive adhesive sheet made of a super-low-hardness elastomer using the super-low-hardness elastomer forming composition. SOLUTION: In the composition for forming a low-hardness elastomer having an Asker C hardness of 30 or less made of (A) a polyisocyanate compound and (B) polyol, the theoretical molecular weight (MWc) of a virtual hydroxide group-terminated prepolymer between a bi-functional aliphatic polyisocyanate compound included in (A) polyisocyanate and (B) polyol falls into the range of 2,100 to 5,000, and the equivalent ratio of isocyanate group/hydroxide group in the isocyanate group of (A) polyisocyanate compound and the hydroxide group of (B) polyol falls into the range of 0.50 to 0.90. COPYRIGHT: (C)2011,JPO&INPIT