initiation of curing furthermore this component exhibits a low vapor pressure and is therefore not removed in the conventional reduced pressure defoaming process and exhibits the effect of a storage stabilizer for the required period of time preferred embodiments of component c also exhibit excellent miscibility with components a and b and therefore do not cause uneven curing the quantity of component d relative to components a and b will be determined by the required storage time following mixing of all components of the present composition typically from 2 to 10 000 moles of component d are present per 1 mole of catalyst preferably from 10 to 150 moles of component d are used per mole of catalyst fillers and other additives may be added to the present composition in order to reduce thermal shrinkage during curing reduce the thermal expansion coefficient of the compositions or gas permeability or increase thermal stability weather resistance chemical resistance flammability or the mechanical strength of the cured elastomer typical additives include fumed silica quartz powder glass fibers carbon black alumina metal oxides such as iron oxide and titanium oxide and metal carbonates such as calcium carbonate and magnesium carbonate in addition pigments dyes blowing agents and antioxidants may be added so.