n dimentylbenzylamine n n dimethylcyclohexylamine and 1 2 dimethylimidazole other catalysts such as silaamines and basic nitrogen compounds such as tetraalkyl ammonium hydroxide alkali metal hydroxides such as sodium hydroxide and alkali metal alcoholates such as sodium methylate also have been used as catalysts these catalysts are generally used in an amount from about 0 01 to about 10 by weight preferably from about 0 05 to about 1 0 by weight based on the quantity of polyisocyanate and the quantity of materials reacting with the polyisocyanate the second stream also may contain materials such as blowing agents and surfactants among suitable blowing agents are water and readily volatile organic substances or dissolved inert gases such as acetone ethylacetate methanol ethanol halogen substituted alkanes including methylene chloride chloroform vinylidene chloride monofluorotrichloromethane chlorodifluoromethane and dichlorofluoro methane butane hexane heptane diethyl ether nitrogen air carbon dioxide etc examples of surfactants include the sodium salts of sulfonates or of fatty acids amine salts of fatty acids alkali metal or ammonium salts of sulfonic acids polyether siloxanes and the like the second component also may contain pigments dyes flame retardants stabilizers plasticizers fungicides and bactericides and fillers as previously noted the blend of backbone polyamine or polyol and the chain extruder amines of our invention may also contain one or more chain extender polyols or a second chain extruder polyamine.