Masses which may be cross-linked to give elastomers with cleavage of alcohols from alkoxysilyl end groups

In a composition which is crosslinkable with elimination of alcohols from alkoxysilyl end groups to give elastomers in the presence of a catalyst, the improvement comprising selecting as at least one catalyst, a tin compound having a coordination number of 5 or 6 and coordinately bonded to a P═O group of a phosphorus compound, the tin compound prepared by reaction of a phosphorus compound having a P═O group, of the formulae (I), (III):

• O═PR1m(OR2)n(OH)3-m-n (I),
• where
• n is 3, where m is 0,
• n is 0, 1, or 2, where m is 1, 2, or 3,
• m+n is 1, 2, or 3,
• R1 and R2 are C1-C30-hydrocarbon radicals, optionally substituted by hydroxy, halogen, or cyano radicals, or radicals of the general formula (II):
• —[(CR32)b—O]c(CR42)d-L-M (II),
• where
• R3 and R4 are independently selected from hydrogen radicals, methyl radicals, and hydroxy radicals,
• b and d are 2 or 3,
• c is an integer from 1 to 15,
• L each independently is a radical selected from the group consisting of —O—, —COO—, —OOC—, —CONR5—, —NR6CO—, and —CO—,
• R5 and R6 each independently are a hydrogen radical or a C1-C10-alkyl radical, and
• M is a monovalent C1-C20-hydrocarbon radical, optionally substituted with hydroxy, fluoro, chloro, bromo, C10-C10-alkoxyalkyl, or cyano groups, with the proviso that on each carbon atom only one of the radicals R3 and R4 may be a hydroxyl radical;
• O═PR7o(NR82)p(OR9)3-o-p (III),
• where
• R7 is as defined for R1,
• R8 is as defined for R1, and where it is possible for the radicals R8 to be bonded to one another,
• R9 is as defined for R1, or is hydrogen,
• o is 0, 1, or 2,
• p is 1, 2, or 3, and
• o+p is 1, 2, or 3,
• or condensates or hydrolysates of compounds of the formulae (I), (III) having one or more P—O—P bonds;
• with
• an organic tin compound of formula (IV):
• R104-rSnXr (IV),
• an organic tin compound of the formula (V):
• R102SnY (V),
• an organic tin compound of the formula (VI):
• R103SnY1/2 (VI),
• an organic tin compound of the formula (VII):
• R10SnY3/2 (VII),
• where
• R10 is C1-C20-hydrocarbon radicals, optionally substituted by halogen radicals or by cyano radicals,
• X is halo, —OH, —OR10, —SR10, —OOCR10, —NR102, —NHR10, —OSiR103 or —OSi(OR10)3,
• Y is O or S, and
• r is the values 1, 2, or 3.