Tin catalysts for use in rim polyol blends containing acidic internal mold release agents and diethyltoluenediamine chain extender

In a polyol-containing B-side composition for reaction with a polyisocyanate-containing A-side composition to make a polyurethane, polyurethaneurea and/or polyurea elastomer by reaction injection molding, which B-side composition also contains an acidic internal mold release composition and diethyltoluenediamine chain extender, the improvement which comprises, per 100 pbw polyol, 0.05 to 0.5 pbw diorganotin dicarboxylate of the following general formula:

• R.sub.2 Sn(O.sub.2 C--R').sub.2
• where
• R is a C.sub.1 -C.sub.8 alkyl, aryl or alkaryl group, and
• R' is a C.sub.1 -C.sub.4 alkyl group having at least one halogen atom which is alpha to the carboxyl functionality.

In a polyol-containing B-side composition for reaction with a polyisocyanate-containing A-side composition to make a polyurethane, polyurethaneurea and/or polyurea elastomer by reaction injection molding, which B-side composition also contains an acidic internal mold release composition which is a carboxy-functional siloxane, the reaction product of a tertiary amine reacted with an epoxide in the presence of a carboxy-functional siloxane, or a fatty acid-containing material, and diethyltoluenediamine chain extender, the improvement which comprises, per 100 pbw polyol, 0.05 to 0.5 pbw diorganotin dicarboxylate of the following general formula:

• R.sub.2 Sn(O.sub.2 C--R').sub.2
• where
• R is a C.sub.1 -C.sub.8 alkyl group, and
• R' is a C.sub.1 -C.sub.4 alkyl group having at least one halogen atom which is alpha to the carboxyl functionality.