The Heat Treatment of Orlon Acrylic Fiber to Render it Fireproof

Abstract

A Method for preparing a black, fireproof textile fiber candidate (called Fiber AF) from Orlon ¹ is described. Fiber AF is prepared by heat treating fibers or fabrics of Orlon, preferably the latter, in air at temperatures in excess of 160° C. The logarithm of the reaction time is inversely proportional to the heating temperature. The important variables found in the process were heating time and temperature, fabric construction, and heating atmosphere. Fiber AF is fireproof and has an unusually high resistance to destruction upon short- time thermal irradiation. Fiber AF can resist thermal irradiation over 100-fold higher than ordinary clothing fabrics. Upon continued exposure to high temperatures, Fiber AF gradually loses its tensile properties. At 900° C., it is completely consumed in 3 hr. While Fiber AF has fair tensile properties, its transverse properties are poor, excluding its possible utility in various types of fireproof garments where good abrasion resistance is required.