Method for Modifying Fibrous Substrates with Siloxan Copolymers

A method of modifying fibrous substrates, comprising contacting said fibrous substrate with at least one siloxane copolymer obtained by

• reacting, in a first step, organopolysiloxane(s) (1) which have at least one silicon-bonded hydrogen atom per molecule, with substantially linear algometric or polymeric compounds (2) of the formula
• R1-(A-CnH2n)m-A1-H (I)
• where R1 is a monovalent optionally substituted hydrocarbyl radical capable of hydrosilylation,
• A is a bivalent polar organic radical selected from the group consisting of —O—, —C(O)—O—, —O—C(O)—, —O—C(O)—O—, —C(O)—NH—, —NH—C(O)—, urethane radicals, and urea radicals,
• A1 is a bivalent polar organic radical selected from the group consisting of —O—, —NH— and —NR′— where R′ is a monovalent hydrocarbyl radical of 1 to 18 carbon atoms,
• n is an integer from 1 to 20, and
• m is 0 or a positive integer,
• to form a H-A1-group-containing intermediate compound (4) and,
• reacting, in a second step,
• the resulting H-A1-group-containing intermediate (4) with at least one organic compound (5) which has two or more isocyanate groups per molecule,
• wherein the mole equivalents of isocyanate groups are less than or equal to the mole equivalents of isocyanate-reactive groups.