This document describes a process for stabilizing textile materials against shrinkage during laundering. Specifically, it involves treating cellulosic materials with non-volatile acetals of monoaldehydes and dialdehydes containing up to eight carbon atoms, and heating the treated material in the presence of an acidic catalyst and curing at over 121°C. Several examples are provided of treating fabrics like viscose with various acetals like glyoxal tetra(methoxyethyl)acetal and obtaining reduced shrinkage after multiple washes compared to untreated fabrics. The process can also produce durable mechanical effects on the textile surface through mechanical working like calendering during curing.