PREPARATION OF URETHANES AND CATALYSTS THEREFOR

1454102 Polyurethanes MINNESOTA MINING & MFG CO 9 Oct 1973 [10 Oct 1972] 47144/73 Heading C3R Non-foamed polyurethanes are prepared by reacting a polyisocyanate with a polyhydroxy compound in the presence of a catalyst which is a mixture comprising: (i) a soft acid (defined) metal compound in which the metal is antimony, molybdenum, titanium, vanadium, tungsten, tin (IV) or tin (II), the tin (II) soft acid metal compounds being stannous salts of carboxylic acids, stannous chloride or stannous iodide, in combination with (ii) a compound having a pK a of greater than 0À23 which possesses no hydroxy substitution and is a carboxylic acid, anhydride of a carboxylic acid or an acetoxy siloxane. Numerous examples of suitable compounds (i) and (ii) are listed, those used in the examples being mixtures of stannous octoate or stannous 2-ethyl hexanoate with 2-ethylhexanoic acid and mixtures of stannous octoate with glacial acetic acid, octanoic acid, cyclohexane acetic acid, isodecanoic, tetrachlorophthalic mono n-hexyl carbitol ester or cis-cyclohexane dicarboxylic mono-n-hexyl carbitol ester. The use of the catalyst mixture results in a longer gel time and a faster cure rate and also an increased pot-life for the reaction mixture.