• Fashion & Textile Research Journal
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• v.20 no.1
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• pp.93-100
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• 2018

This study comparatively analyzed the changes in the dimensional stability and the mechanical properties of stretch knit fabrics associated with washings conditions in order to determine the most appropriate washing method. Polyester and spandex knit fabrics were washed 25 cycles with nine washing condition profiles that controled detergent, hardness. temperature and RPM. The knit fabrics with repeated washings were evaluated by dimensional stability and measured by the KES-FB system. Polyester and spandex fibers have good chemical resistance. However, the changes in the dimensional stability and the mechanical properties were observed in washed knit fabrics. After repeated washings, the knit fabrics washed in an alkali or neutral detergent had good dimensional stability compared with the knit fabric washed in functional detergent. The washed knit fabrics were extended, stiff, rough, and had a smaller volume. The changes were the result of the rearrange of polyester fibers which twisted around spandex core and chemical interactions involving the detergent and the physical and mechanical forces of washing. Especially, using an alkali detergent resulted in increased stiffness and roughness of the knit fabric. In conclusion, the washing in water with low hardness and a neutral detergent can minimize the changes in dimensional stability and mechanical properties of polyester and spandex knit fabric.