ON THE SOFTNESS AND SHEARING PROPERTIES OF SILK FABRICS

Abstract

The pliable handle of textile fabrics different from paper and plastic film may be due to the large deformation in shear.
In this paper, firstly the typical load-deformation curves in shear of silk fabrics such as Habutae, crepe and taffeta, and more nonwoven fabric, paper and glass cloth are discussed generally, secondly the softness of silk fabrics are examined by the relation between bending stiffness EI and shear angle _??_, and finally the relationships between air quantity ratio and shear properties, and also the relations between sensory scale values of softness and flexural rigidities and shear angles for Habutae cloths were investigated. The results obtained were as follows:
1. The shapes of shearing load-deformation curves are different by the kinds of fabrics. They may be explained by the effects of frictional and elastic forces, on the other hand the character of fabric can be assumed by the shape of load-deformation curve in shear.
2. The relation between the bending stiffness EI and shear angle _??_ of silk fabrics shows an inverse correlation. Assuming that softness is dependent on shear angle _??_ and liveliness depends upon bending stiffness EI for silk fabrics, it is considered that when both EI and _??_ of fabrics are large its fabric will show soft and lively handle.
3. Shear angle for Habutae cloths increase as the air quantity ratio increase. The air quantity ratio on Habutae cloths is related to shear angle _??_ and apparent specific gravity and percentage of air quantity in the fabric. The sensory values of softness on Habutae cloths are largely connected with shear angle _??_ rather than in flexural rigidity EI. From the above fact it is considered that Habutae cloths become soft in proportion to the air quantity ratio increase and also the deformation in shear increase.