In the previous report (A. TAKAOKA, J. Soc. Textile & Cellulose Inds. Japan, 18, 741 (1962)), the effects of heat-treatment of acrylic fiber on its dyeing properties had been investigated to determine if such heat-treatments prior to dyeing could be a major cause of variations in hue.
In this report, the effects of heat-treatment of acrylic fiber on its physical and chemical properties have been investigated to discuss the relation between dyeing properties and fiber structure. Samples of Orlon 42 were treated with hot water (100°-150°C), steam (100°-150°C), and hot air (100°-200°C) without tension, and then their physical properties (shrinkage, apparent fineness, specific gravity, tensile strength, breaking elongation, Young's modulus and whiteness) were measured. On the other hand chemical properties were examined by means of infrared spectrum analysis, elementary analysis (nitrogen content) and potentiometric titration (acid group content).
With regard to the effects of wet heat-treatment, the fibers shrank markedly, apparent fineness and wet breaking elongation increased, and tensile strength (g/d) and Young's modulus decreased. The higher the temperature of the heat-treatment is, the greater this tendency becomes. The effects of dry heat-treatment on the fiber properties are, by comparison, negligible. Specific gravity measured by means of the density gradient tube method increases a little both in wet heat-treatment and in dry one, but the increment is not so large as to discuss on the effects of heat-treatment conditions. High temperature treatment makes the fibers slightly yellow in both treatments, but no marked chemical change of the fibers is recognized from the results of infrared spectrum analysis and nitrogen analysis. It was however recognized that the acid group content decreases about 10% on hot water treatment at 140° and 150°C.
From these results, the change in dyeing properties on heat-treatment is reconfirmed to be due to the physical change of the fibers.
抄録全体を表示