STUDIES ON SHRINK PROOFING OF WOOL WITH POLYMER

1. PROCEDURE FOR POLYURETHANE FINISH OF WOOL

Abstract

Various methods were used in treating a worsted fabric and a yarn with urethane prepolymer (adduct) synthesized from polypropylene glycol (P. P. G.) and a little excess of tolylene diisocyanate.
Procedure I. Two-stage-treatment by using hexamethyl ene-diamine (H. M. D. A.) and adduct in CCl₄
Procedure II. The same as Procedure I, except that water was used instead of H. M. D. A.
Procedure III. First impregnated with ice cooled organic solution containing H. M. D. A. and adduct, and then open cured.
Procedure IV. First impregnated with CCl₄ solution of adduct, and then open cured.
Procedure V. The same as Procedure IV except that “closed cured in nitrogen” instead of being “open cured”.
Among these, Procedure I, is the most commendable technique for obtaining unshrinkability of wool.
The effects of P. P. G. average molecular weights---400, 1000 and 2000---on polyurethane finished wool was investigated, and it was observed that with the increase of the molecular weight, the handle of the worsted fabric became softer and its shrink resistant property greater.
After the treatment, crease recovery of worsted fabric remains is unchanged but its strength became greater.
Yellowing caused by this polyurethane finish is small and it is not accelerated after the treatment.