Study On Dimensional Stability Of Soybean Knitted Fabric

Soybean fiber is a new type of protein fiber which is developed independently and produced commercially by Chinese specialists. The fiber has many good properties of the natural fiber and chemical fiber. Its foreground is very good. However, the fiber has some deficiencies such as less curl texture and heat sensitivity, which results in some trouble in dimensional stability. To improve further the properties of soybean knitted fabric, the knitting, dyeing and finishing technology of soybean knitted fabric were studied in this thesis. From above discussion the optimal data of production can be derived.This thesis pays some emphasis on the dimensional stability of the soybean knitted fabric. The affecting factors on the dimensional stability of the soybean knitted fabric were found from knitting technology, the interlacing with the lycra and PTT, dyeing and heat setting technology, and the improving measures were put forward.To make foundation of the following study the properties of the yarns were tested. It was found that the soybean spun yarn has such characteristics as higher strength and breaking elongation rate, less hairness on appearance comparing with cotton yarn. At the same time soybean spun yarn has higher thermo-hydro shrinkage, which is increasing remarkably with the increasing of the temperature of water bath.The relation between opening percentage and shrinkage of the knitted fabric was analyzed in this thesis. The dimensional stability of soybean knitted fabric is optimal when the opening percentage ranges from 16 to 17.5. As to cotton knitted fabric, when the opening percentage ranges from 13 to 16, the dimensional stability of fabric is optimal.The properties of the soybean knitted fabric can be improved by interlacing with lycra or PTT. For the fabric made of soybean protein yarn and lycra, it has less shrinkage, better dimensional stability, higher breaking strength and elastic recovery percentage of elongation, worse drapability and permeability. The changing degree of these properties is high as the content of lycra is increasing. As to the fabric interlaced with PTT, it has less shrinkage, which decrease with the increasing of content of PTT. Its breaking strength and elastic recovery percentage of elongation become higher but the permeability decreases.The relation between the dyeing and thermosetting technology of soybean knitted fabric and its dimensional stability was studied in this thesis, the optimal dyeing and thermosetting condition was obtained with the help of orthogonal experiment.