Crosslinkable siloxanes by acid-catalyzed polymerization of oxasilacycles

A process for preparing oxasilacycles of the formula (5)

• comprising reacting compounds of the formula (2),
• with siloxanes of the formula (3),
• RO—Si(R7)2O[Si(R7)2O]oSi(R7)2—OR (3),
• where
• R is hydroxy, or an unsubstituted or substituted hydrocarbonoxy radical or acyloxy radical having from 1 to 50 carbon atoms,
• R1′, R2′ are each hydrogen, halogen, cyano, OH, or an unsubstituted or substituted hydrocarbonoxy radical, acyloxy radical, alkoxy radical or hydrocarbon radical having from 1 to 50 carbon atoms, in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S, and where two or three of the radicals R1, R2, R1′, R2′, R1″,
• R2″ are optionally joined to one another,
• R3′, R4′ are each an unsubstituted or substituted hydrocarbon radical having from 1 to 50 carbon atoms, in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S, or a high molecular weight radical,
• R5 is an unsubstituted or substituted hydrocarbon radical having from 1 to 10 carbon atoms,
• R6 is an unsubstituted or substituted hydrocarbon radical having from 1 to 50 carbon atoms, n which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S,
• R7 is an unsubstituted or substituted hydrocarbon radical having from 1 to 10 carbon atoms,
• n′ is an integer of at least 1,
• o is an integer of at least 0 and
• s is an integer of at least 1.

A process for crosslinking siloxanes of formula (4) and (7) comprising crosslinking by free-radical, cationic, anionic or coordination polymerization via terminal double bonds:

• where
• R are hydrogen, or an optionally substituted C1-50 hydrocarbon radical or C3-50 acyl radical,
• R1, R2, R1′, R2′, R1″, R2″ are hydrogen, halogen, cyano, OH, or an optionally substituted C3-50 hydrocarbonoxy radical C1-50, acyloxy radical, C1-50 alkoxy radical or C1-50 hydrocarbon radical, in which nonadjacent carbon atoms in each case are optionally replaced by heteroatoms N, O, P, and or S, and where two or three of the radicals R1, R2, R1′, R2′, R1″, R2″ are optionally joined to one another,
• R3, R4, R3′, R4′, R3″ are optionally substituted C1-50 hydrocarbon radicals in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S, or a high molecular weight radical,
• R4″ are hydrogen, or optionally substituted C1-49 hydrocarbon radicals in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S, or are high molecular weight radicals,
• R6 are optionally substituted C1-50 hydrocarbon radicals in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S,
• R7, R10 are optionally substituted C1-10 hydrocarbon radicals having from 1 to 10 carbon atoms,
• R8 are radicals R6 or R9,
• R9 are radical of the formula (6)
• n, n′, n″ are integers of at least 1,
• x, y, y1 are each 0 or 1,
• z is an integer of at least 1,
• o is an integer of at least 0,
• p is an integer of at least 1,
• s is an integer of at least 1, and
• EG is a hydrocarbon or silyl group.

A process for the polymerization of oxasilacycles of the formulae (1) and (5)

• comprising polymerizing the oxasilacycles of the formulae (1) and/or (5), and optionally linear siloxanes of the formula (3) and/or cyclic siloxanes of the general formula (3a)
• in the presence of an acid catalyst K
• where
• R are hydrogen, or an optionally substituted C1-50 hydrocarbon radical or C1-50 acyl radical,
• R1, R2, R1′, R2′, R1″, R2″ are hydrogen, halogen, cyano, OH, or an optionally substituted C1-50 hydrocarbonoxy radical C1-50, acyloxy radical, C1-50 alkoxy radical or C1-50 hydrocarbon radical, in which nonadjacent carbon atoms in each case are optionally replaced by heteroatoms N, O, P, and/or S, and where two or three of the radicals R1, R2, R1′, R2′, R1″, R2″ are optionally joined to one another,
• R3, R4, R3′, R4′, R3″ are optionally substituted C1-50 hydrocarbon radicals in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S, or a high molecular weight radical,
• R4″ are hydrogen, or optionally substituted C1-49 hydrocarbon radicals in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S, or are high molecular weight radicals,
• R6 are optionally substituted C1-50 hydrocarbon radicals in which nonadjacent carbon atoms are optionally replaced by heteroatoms N, O, P, and/or S,
• R7, R10 are optionally substituted C1-10 hydrocarbon radicals having from 1 to 10 carbon atoms,
• n, n′ are integers of at least 1,
• o is an integer of at least 0,
• s is an integer of at least 1,
• to form a polymeric product.