A New Catalyst System for Cross-Linking Cotton Cellulose with Formaldehyde

A dual catalyst system containing magnesium and fluoborate ions facilitates the cross-linking of cotton cellulose with formaldehyde. Compared with previous formaldehyde cross-linking processes, the dual catalyst system permits operating at lower temperatures, shorter curing times, and lower concentrations of formaldehyde to produce high and nonvariable wash-wear characteristics which are durable in home and commercial launderings. In addition, this dual catalyst system may be used to impart durable-press properties to cotton fabric by using either pre-cure, partial cure, or post- cure techniques.

The magnesium cation seems to be unique in the dual catalyst system, since other divalent cations, e.g., barium and zinc, do not act synergistically with fluoborate. The role of fluoborate is discussed and data are shown which indicate that boron trifluoride is the active species which accelerates the cross-linking reaction in the presence of magnesium. ¹⁴Carbon tracer studies reveal that, under equivalent processing conditions, more formaldehyde is bound to cellulose by the dual catalyst system than by a single catalyst (magnesium chloride) system.