Shrinkage properties of fabrics of high-modulus viscose rayon staple fibre

Abstract

In this article the writers investigate the shrinkage properties of fabrics processed from high-modulus fibres and compare them with the same properties of fabrics produced from ordinary viscose rayon staple fibre. The fabric of high-modulus fibre used in the investigation was chosen for its versatility. The investigation was carried out with staple fabric Article 72110 and ordinary plainweave fabrics of the same density. The shrinkage properties of these fabrics after repeated washing were analyzed in the normal operating conditions of a self-servlce laundry, The specimens were passed through all the stages of the washing and finishing process in laundries. The shrinkage was determined after one, three, five, I0, 40, and 50 washing and finishing cycles. Two methods of washing were employed, at 60°C for colored and 90°C for white fabrics, using a steam-heated KP-II3 washing machine; the pH of the washing liquor was i0.5~ii.5. The shrinkage was determined after the above washing cycles in accordance with GOST 9715--76. The diagram in Fig. 1 shows that the fabrics shrink warpwise mainly in the first few washing cycles -- the first to the 10th. A further increase in the number of washing cycles leaves the shrinkage of the fabrics from high-modulus fibre almost unchanged (curves i, 3) but the shrinkage of the viscose rayon staple fabrics continues to increase (curves 2, 4). At a washing temperature of 60°C the maximum shrinkage of the ordinary rayon staple fabric is 10% and that of the fabric from high-modulus fibre 3.2% while at a washing temperature of 90°C the maximum shrinkages are 11.8 and 4.1%, respectively. The warpwise shrinkage of the fabric of high-modulus fibre is therefore three times lower than that of the ordinary rayon staple fabric. The effect of the increase in the washing temperature on the shrinkage of the fabric of high-modulus fibre is only marginal. At a washing temperature of 90°C the shrinkage is 0.5-1.0% higher than at 60°C. The diagram in Fig. 2 shows the weftwise shrinkage of the fabrics vs the number of washing cycles at washing temperatures of 60 and 90°C. The pattern of the curves describing the variation of the weftwise shrinkage of the fabrics with the number of washing cycles shows that in both types of fabric the shrinkage reaches a maximum in the first few washing cycles.