Abstract
A catalyst system effective for either precure or postcure durable-press finishing under curing mild conditions has been developed. Mixtures of ammonium chloride and phosphoric acid or certain organic acids provide adequate catalysis for finishing cotton or cotton-containing fabrics with carbamates or certain other nitrogenous agents under mild-cure con ditions. The catalyst mixtures are not as strong as the mineral acids which were originally required for mild-cure finish ing. As a result, less closely controlled curing conditions can be used. Furthermore, there is no additional strength loss if finished fabric is not immediately neutralized and washed after treatment as occurs with mineral acid catalysis.
Advantage has been taken of this combination of features to propose a modified postcure durable-press finishing process. A "sensitized" material is produced by treating fabric impregnated with a cross-linking agent and catalyst mixture at 60-100°C. This material can be pressed to shape and postcured at 100°C to give fabric that is smooth and durably creased after laundering with either tumble- or line-drying. The combination of time and temperature that is operative in this postcure treatment is markedly less than that of the present, widely practiced, postcure process.
The ammonium chloride/acid catalyst system also appears attractive for precure treatment of polyester/cotton blend fabrics with formaldehyde at mild-cure temperatures. Finished 50/50 polyester/cotton fabrics had durable-press ratings of 4 and above even after line-drying. Ratings of this level are generally difficult to obtain upon line-drying of synthetic- containing blends.