Improving the Process for Treating Cotton Fabrics with Crosslinked Polyols

Addition of NaCl to pad bath solutions contaimng polyethylene gly col (50% PEG-1,000), crosslinking resm (11% DMDHEU) and mixed acid catalysts (3.3% MgCl₂ · 6H ₂O/citric acid) substantially mcreased the add-on of 100% cotton fabrics (compared to fabrics treated with solutions without salt) when they were dried and cured. Fabrics comprised of synthetic fibers (e.g., polypropylene) and cot ton blend fabrics containing 50% or more of synthetic fibers had only slightly higher weight gains when salt was in the pad bath solution. Concentrations of added NaCl were varied from 1 to 10% by weight and molar ratios of mixed acid catalysts were varied from 10/1 to 1/1 (MgCl₂ · 6H₂O/citric acid). Concentrations of added NaCl and mixed catalyst ratios to obtain highest weight gams in the cotton fabrics were 5% and 5/1, respectively. Higher weight gains for cellulosic fabrics are attributed to reduction in penetration of the DMDHEU into the fiber due to an increase in the viscosity of the polyol solutions when NaCl is present, thus permitting optimum reaction of resin with the polyol at the fiber surface. The mode of action of the NaCl is also briefly discussed in relation to hypotheses that are consistent with fundamen tal polymer and physical chemistry.