The aforementioned catalyst may be used alone or as a mixture of two or more of the aforementioned catalysts.Amino compounds having an alkoxysilyl group, e.g. 3-amino-propyltrimethoxysilane are also suitable as catalysts.Preferred catalysts to control the curing rate of the inventive curable compositions include, for example, organometal compounds such as iron or tin compounds, in particular the 1