In order to delineate the effects on reagent migration on the textile-performance properties of durable-press fabrics, dimethyloldihydroxyethyleneurea (DMDHEU) and N-methylolpolyethyleneurea, degree of polymerization = 2, were applied to cotton printcloth under slow and rapid drying conditions, which effected uniform and nonuniform crosslink distributions through the fabric thickness. These reagents are representative of conventional and network polymer forming cross-linking reagents, respectively. The crosslink uniformity (or nonuniformity) was measured in the DMDHEU series with a negative Direct Red 81 staining technique. Fabrics with a uniform distribution of crosslinks throughout the fabric thickness were the point of reference. The concentration of crosslinks on fabric surfaces effected by reagent migration during rapid drying resulted in a) comparable development of resilience, b) slightly better retentions of breaking strength, tearing strength, and elongation, c) greater weight losses in Accelerotor abrasion, and d) comparable retention of Stoll-flex abrasion resistance. These trends occurred with both reagent systems and were detected at both the low and high levels of reagent incorporation. The results are discussed in relation to the distribution of crosslinks.

The balance of textile performance properties and the distribution of crosslinking reagent residues throughout fabric were studied in relation to lick roller application of DMDHEU. Features of the lick roller treated fabric were compared to the conventional pad(immersion)-dry-cure product and to a corresponding product designed to have a high degree of uniformity of reagent residue distribution throughout the thickness of the fabric by minimizing migration. A special Osnaburg-fabric was used to facilitate several aspects of the study including the measurement of distribution of reagent residues. The fabric treated to a high degree of uniformity of reagent residue distribution exhibited substantially higher abrasion resistance than the conventional product when compared at equal levels of durable press appearance rating; it was slightly lower in strength properties. The product from lick roller treatment at optimum liquor pickup approached the high uniformity standard in uniformity of reagent residue distribution throughout the fabric thickness and in abrasion resistance. In breaking strength, tearing strength, and elongation (especially in the warp), this product from lick roller treatment performed close to the high uniformity standard. The performance of another product from lick roller treatment that involved lower liquor pickup is also described, Performance properties and distributions of reagent residues are discussed in detail.

The pore structure of cotton was followed through three pretreatments that com monly precede chemical modification for imparting easy care or other functional properties. These treatments included scouring/bleaching, caustic mercerization, and a liquid ammonia treatment with removal by volatilization at elevated temperature. The results include data on the pore structure of the fiber in the greige state. A reverse gel permeation chromatographic technique was used. Columns were prepared from whole cotton fibers in the form of batting, and three series of water soluble solutes were used to study their elution characteristics. The solutes were series of oligomeric sugars, ethylene glycols, and glymes ( ethylene glycol dimethyl ethers) with molecular dimensions in the range of conventional finishing agents for cotton. Scouring/bleaching decreased the water holding capacity of the greige cotton as measured by water of imbibition, but increased it as indicated by gel permeation measurements. The internal volume accessible to water was substantially increased by caustic mercerization, but was only slightly affected by liquid ammonia treatment. The relative accessibility of the cotton fibers to molecules the size of durable press finishing agents was slightly increased by scouring/bleaching, substantially increased by caustic mercerization, but moderately reduced by liquid ammonia treatment. Accessibility to molecules near the permeability limits of the fibers followed similar trends, but differences were greater. Scouring/bleaching increased the permeability limit of the greige fibers, but subsequent mercerization or liquid ammonia treatment decreased it. There was a noteworthy difference in permeability limit and relative accessibility to large molecules. This is accounted for by a decrease in the rate of change in pore size on scouring/bleaching, but substantial increases, to generally more than double, on subsequent caustic mer cerization or liquid ammonia treatment of the scoured / bleached cotton.

Migration of dimethyloldihydroxyethyleneurea in the thickness direction of fabric was examined under conditions of forced-draft drying at temperatures from 40°C to 160°C. The subsequently cured fabrics were subjected to de Boer migration mea surements to clarify extents of migration of reagent residues to fabric surfaces. Migration was a primary function of forced-draft drying; differences in temperature of drying exerted no additional distinguishable effect. Unhalanced and variable migrations were observed for forced-draft drying in common laboratory ovens. Durable-press ap pearance rating is discussed in relation to add-on of reagent for the products of these treatments.

Pore structures of cotton fabric crosslinked with several formaldehyde-free durable press reagents are elucidated, and results are compared with those for the industry standard, DMDHEU (dimethyloldihydroxyethyleneurea). The formaldehyde-free reagents were BTCA (butanetetracarboxylic acid), DHDMI (dihydroxydimethylimidazolidinone), and the glyoxal/glycol system; the fabric was an 80 × 80 cotton print-cloth. Treatments were designed to impart the same degree of conditioned wrinkle recovery (WRA) to the fabric. A reverse gel permeation chromatographic technique was used to follow changes in pore size distribution. Columns were prepared by settling water slurries of the ground cotton in a conventional manner. Two series of water soluble solutes, which were series of oligomeric sugars and ethylene glycols, were used to study the elution characteristics of the unmodified and crosslinked samples. Internal structure differences were also elucidated by means of moisture regain, considered to be a measure of the internal surface of the cotton fiber in the conditioned state, and water of imbibition, a measure of internal volume in the water-swollen state. Formaldehyde-free crosslinking reagents effect a lower level of collapse of the internal pore structure of the cotton fiber than does DMDHEU at generally comparable levels of resilience.