Abstract: Crosslinkable polymers, suitable for use in the finishing of keratinous fibres such as wool, have polyoxyalkylene chains in which the alkylene groups consist of unbranched chains of not less than 3 carbon atoms. The polymer molecule contains at least two groupings capable of crosslinking, for example thiol, isocyanate, or thiosulphate groups, and the molecule also contains at least two carboxylic acid residues at least one of which is the residue of a polycarboxylic acid. The polyoxyalkylene chains are themselves linked at both ends to the rest of the molecule by carboxylic ester linkages. Particularly preferred compounds are water soluble and contain one or more solubilizing groups such as thiosulphate or the bi-sulphite adduct of isocyanate or, in the case of compounds with thiol groups, salt forming carboxylic groups. The compounds may be applied to textile fibres as aqueous emulsions or solutions and may be cured by drying in hot air or by steam.