Patent ID: 6890895

Claim:
A method of softening and conditioning natural and synthetic fibers with compositions that include more than 40% by weight of fiber conditioning non-ionic surfactants, based on the total weight of softening active substances, which comprises introducing into said fibers a cationic surfactant obtainable by the formation of addition salt of an alkanolamine ester with a mineral organic acid or by quaternization of an alkanolamine ester by reaction with an alkylating agent, said alkanolamine ester prepared by the esterification reaction of an alkanolamine of the general formula (I) with a dicarboxylic acid, or with a reactive derivative thereof, of the general formula (II) HOOC—R 4 —COOH (II) with an optionally alkoxylated fatty alcohol of the general formula (III) in which formulae R 1 is hydrogen, a C 1 -C 6 alkyl group or the residue R 2 is a C 1 -C 6 alkylene group, R 3 is hydrogen or methyl, n is 0 or an integer from 1 to 20, R 4 is an optionally substituted or unsaturated C 1 -C 36 alkylene group, or arylene, and R 5 is a linear or branched C 2 -C 22 alkyl or alkenyl group and with a fatty acid of the general formula (IV) R 6 —COOH (IV), in which R 6 is a linear or branched C 6 -C 23 alkyl or alkenyl group, or an alkyl ester or a glyceride of the fatty acid, and/or an optionally alkoxylated polyol is incorporated into the esterification.