Some Properties of Viscose Rayon Fabrics Treated with Tetrakishydroxy Phosphonium Chloride (THPC) Resins

Abstract

Data are reported on the moisture regain, water of imbibition, tear strength, elastic properties, and flame resistance of chemically modified viscose rayon fabrics.

The data reveal that THPC behaves as if it were a derivative of formaldehyde. Under moderate curing conditions, substitution of hydroyxy groups in cellulose occurs, but when curing conditions are more severe, cross-linking takes place. Both triethanolamine and urea inhibit the reaction of THPC with cellulose and reduce acid degradation. Treatment of fabric with THPC-urea or THPC-melamine resins also leads to polymer deposition, especially at high curing temperatures. Both in the presence and absence of urea, when substantial quantities of triethanolamine are added, THPC decomposes, and the amount of phosphorus fixed is reduced. Triethanolamine appears to act in a complex manner; its effect is due not solely to its alkalinity. Only in the presence of urea does the fabric acquire flame resistance, although phosphorus is fixed even in the absence of urea. Fabric aminized with 2-amino ethyl sulfuric acid is on subsequent treatment with THPC, also flameproofed. Due to the presence of amino groups in the fabric, however, THPC reacts with fewer hydroxyl groups, and the losses in tear strength are less.