In the context of the invention, esterquats are understood to be quaternized carboxylic acid monoesters, diesters or triesters corresponding to general formula (I): in which R1CO??? is a saturated and/or unsaturated acyl group containing 2 to 22 carbon atoms, more especially 2 to 12 carbon atoms and preferably 8 to 10 carbon atoms, R2 is an optionally substituted, linear or branched alkyl, alkenyl