Investigation of Flexible Crosslinking Systems for the Retention of Mechanical Strength and Abrasion Resistance in Durable Press Cotton Fabrics

N-methylol compounds, such as dimethyloldihydroxyethyleneurea (DMDHEU), are the most commonly used durable press finishing agents for cotton fabrics. Polyfunctional carboxylic acids are becoming important as non-formaldehyde replacements for these N-methylol reactants. The use of both chemistries has been shown to cause an irreversible reduction in the physical properties of finished fabric, beyond the reversible embrittlement caused by the actual crosslinking. This non-recoverable loss in properties has been ascribed to being due to depolymerization of cellulose caused either by the catalyst used for DMDHEU or by the presence of a protic acid. Multiple angle Laser light scattering was used to measure the molecular weight of cellulose in cotton fabrics treated with polycarboxylic acids and a Lewis acid. The overall results indicate a direct correlation between tensile strength loss of the treated cotton fabric and the molecular weight of cellulose. In addition, there is a direct correlation between wrinkle recovery angle and percent tensile strength loss, independent of the chemistry and crosslink structure used to react the fabric. Preliminary results on the retention of flex abrasion resistance indicate that this fabric property is also very sensitive to the nature of the catalysts and chemistries used in the durable press finishing process. Introduction Since the late 1980s, the casual wear market place has shown a steady increase in the demand for easy care, wrinkle-resistant 100% cotton apparel. The tensile strength, tearing strength and abrasion resistance of the durable press finished cotton fabrics are significantly reduced as a result of this finishing process. Severe tensile strength loss and poor abrasion resistance are the