Compositions comprising 100 parts by weight of silane-crosslinking polymers of the formula x -Y-[O-CO-NH-(CR 1 2) b -SiR a (OR 2) 3-a] 2-x where Y is a divalent polymer radical, R may be the same or different and is a monovalent, optionally substituted hydrocarbyl radical, R 1 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 2 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, x is 0 or 1, a may be the same or different and is 0, 1 or 2 and b may be the same or different and is an integer from 1 to 10, with the proviso that component includes less than 15 mol% of polymers of the formula with x = 1, and 5 to 500 parts by weight of silane-crosslinking polymers of the formula R 6 -Q-Z-[O-CO-NH-(CR 4 2) d -SiR 3 c (OR 5) 3-c] 1-y y where Z is a divalent polymer radical having no hydroxyl group, R 3 may be the same or different and is a monovalent, optionally substituted hydrocarbyl radical, R 4 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 5 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 6 is a monovalent, optionally substituted hydrocarbyl radical, y is 0 or 1, c may be the same or different and is 0, 1 or 2 and d may be the same or different and is an integer from 1 to 10, with the proviso that component includes less than 15 mol% of polymers of the formula with y = 1, 100 parts by weight of silane-crosslinking polymers of the formula x -Y-[O-CO-NH-(CR 1 2) b -SiR a (OR 2) 3-a] 2-x where Y is a divalent polymer radical, R may be the same or different and is a monovalent, optionally substituted hydrocarbyl radical, R 1 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 2 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, x is 0 or 1, a may be the same or different and is 0, 1 or 2 and b may be the same or different and is an integer from 1 to 10, with the proviso that component includes less than 15 mol% of polymers of the formula with x = 1, and Y is a divalent polymer radical, R may be the same or different and is a monovalent, optionally substituted hydrocarbyl radical, R 1 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 2 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, x is 0 or 1, a may be the same or different and is 0, 1 or 2 and b may be the same or different and is an integer from 1 to 10, 5 to 500 parts by weight of silane-crosslinking polymers of the formula R 6 -Q-Z-[O-CO-NH-(CR 4 2) d -SiR 3 c (OR 5) 3-c] 1-y y where Z is a divalent polymer radical having no hydroxyl group, R 3 may be the same or different and is a monovalent, optionally substituted hydrocarbyl radical, R 4 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 5 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 6 is a monovalent, optionally substituted hydrocarbyl radical, y is 0 or 1, c may be the same or different and is 0, 1 or 2 and d may be the same or different and is an integer from 1 to 10, with the proviso that component includes less than 15 mol% of polymers of the formula with y = 1, Z is a divalent polymer radical having no hydroxyl group, R 3 may be the same or different and is a monovalent, optionally substituted hydrocarbyl radical, R 4 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 5 may be the same or different and is a hydrogen atom or a monovalent, optionally substituted hydrocarbyl radical, R 6 is a monovalent, optionally substituted hydrocarbyl radical, y is 0 or 1, c may be the same or different and is 0, 1 or 2 and d may be the same or different and is an integer from 1 to 10,