Compositions comprising 100 parts by weight of silane-crosslinking polymers, selected from polymers of the formula R 2 -O-Z 1 -O-CO-NH-(CH 2)-SiR a (OR 1) 3-a and polymers of the formula R 4 -O-Z 2 -O-CO-NH-(CH 2) 3 -Si(OR 3) 3, where Z 1 denotes divalent polymer radicals which are free from C-bonded hydroxyl groups, Z 2 denotes divalent polymer radicals which are free from C-bonded hydroxyl groups, R may be identical or different and represents a monovalent, SiC-bonded, optionally substituted hydrocarbyl radical, R 1 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, R 3 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, R 2 represents monovalent, optionally substituted hydrocarbyl radicals, R 4 represents monovalent, optionally substituted hydrocarbyl radicals, and a is 0 or 1, 0 to 300 parts by weight of silane-crosslinking polymers having at least two end groups of the formula -SiR 7 c (OR 8) 3-c, where R 7 may be identical or different and represents monovalent, SiC-bonded, optionally substituted hydrocarbyl radicals, R 8 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, and c is 0, 1 or 2, and also 20 to 400 parts by weight of a tackifier resin, characterized in that tackifier resin comprises compounds selected from phenol-modified terpene resins, hydrocarbon resins, rosins, and acrylic ester resins. 100 parts by weight of silane-crosslinking polymers, selected from polymers of the formula R 2 -O-Z 1 -O-CO-NH-(CH 2)-SiR a (OR 1) 3-a and polymers of the formula R 4 -O-Z 2 -O-CO-NH-(CH 2) 3 -Si(OR 3) 3, where Z 1 denotes divalent polymer radicals which are free from C-bonded hydroxyl groups, Z 2 denotes divalent polymer radicals which are free from C-bonded hydroxyl groups, R may be identical or different and represents a monovalent, SiC-bonded, optionally substituted hydrocarbyl radical, R 1 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, R 3 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, R 2 represents monovalent, optionally substituted hydrocarbyl radicals, R 4 represents monovalent, optionally substituted hydrocarbyl radicals, and a is 0 or 1, Z 1 denotes divalent polymer radicals which are free from C-bonded hydroxyl groups, Z 2 denotes divalent polymer radicals which are free from C-bonded hydroxyl groups, R may be identical or different and represents a monovalent, SiC-bonded, optionally substituted hydrocarbyl radical, R 1 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, R 3 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, R 2 represents monovalent, optionally substituted hydrocarbyl radicals, R 4 represents monovalent, optionally substituted hydrocarbyl radicals, and a is 0 or 1, 0 to 300 parts by weight of silane-crosslinking polymers having at least two end groups of the formula -SiR 7 c (OR 8) 3-c, where R 7 may be identical or different and represents monovalent, SiC-bonded, optionally substituted hydrocarbyl radicals, R 8 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, and c is 0, 1 or 2, and also R 7 may be identical or different and represents monovalent, SiC-bonded, optionally substituted hydrocarbyl radicals, R 8 may be identical or different and represents hydrogen atom or monovalent, optionally substituted hydrocarbyl radicals, and c is 0, 1 or 2, 20 to 400 parts by weight of a tackifier resin, characterized in that tackifier resin comprises compounds selected from phenol-modified terpene resins, hydrocarbon resins, rosins, and acrylic ester resins. phenol-modified terpene resins, hydrocarbon resins, rosins, and acrylic ester resins.