Internal release agents, active hydrogen containing mixtures which contain such agents and the use thereof in a process for the production of molded products

An active hydrogen group containing mixture comprising:

• a) one or more compounds having molecular weights of from 400 to 10,000 and containing at least two isocyanate reactive groups,
• b) one or more compounds having molecular weights of 62 to 399 containing at least two isocyanate reactive groups, and
• c) from about 4 to about 12% by weight based upon the amount of components a) and b) of the reaction product of i) an ester having an acid number of 15 or less, prepared by reacting (1) one mole of a tetrahydroxy compound prepared by reacting one mole of a C.sub.2 to C.sub.8 alkylene diamine with from 4 to 12 moles of an alkylene oxide, with (2) four moles of an acid mixture consisting of at least one saturated monocarboxylic acid and at least one unsaturated monocarboxylic acid, with the molar ratio of saturated to unsaturated acid being from 1:1 to 3:1 and ii) a neutralizing amount of a neutralizing agent selected from the group consisting of sodium bicarbonate, cesium bicarbonate, and zinc oxide, said reaction product having an acid number of one or less.

In a process for the preparation of a molded product comprising mixing an isocyanate and an active hydrogen containing material to form a reaction mixture, injecting said reaction mixture into a mold via the RIM process, allowing said reaction mixture to fully react to form said molded product, and removing said molded product from said mold, the improvement wherein said reaction mixture contains from about 4 to about 12% by weight based upon the amount of active hydrogen containing material of the reaction product of i) an ester having an acid number of 15 or less, prepared by reacting (1) one mole of a tetrahydroxy compound prepared by reacting one mole of a C.sub.2 to C.sub.8 alkylene diamine with from 4 to 12 moles of an alkylene oxide, with (2) four moles of an acid mixture consisting of at least one saturated monocarboxylic acid and at least one unsaturated monocarboxylic acid, with the molar ratio of saturated to unsaturated acid being from 1:1 to 3:1 and ii) a neutralizing amount of a neutralizing agent selected from the group consisting of sodium bicarbonate, cesium bicarbonate, and zinc oxide, said reaction product having an acid number of one or less.