Polyester thread is divided into short fiber thread and long silk thread. Generally, high strength thread refers to the long silk thread with high tension.
Such as the strength and its unevenness, the breaking elongation and its unevenness, the elastic elongation and its recovery rate, and the yellowing of the yarn can reflect the deformation processing damage and the service performance of the continuous filament polyester thread. The recovery rate, swelling degree, network degree, thermal shrinkage rate of coil curvature and coil elasticity which express deformation effect and stability. The appearance defects that may occur during the reaction deformation, such as wool defect or hair defect, adhesion and untwisted defect, abnormal crimping that is different from the normal crimping form, uneven dyeing caused by different yarn structure or deformation effect or uneven density in the drum, and yarn defects such as stiff yarn, stain and bad winding shape. Under specified conditions, the ability of high-strength sewing thread to form good stitches while maintaining certain mechanical properties, called stitchability, is a comprehensive index to evaluate the quality of stitches. According to the sewing material, thickness, organization, color, sewing style, sewing equipment or means, the selection of the type and specification of matching stitches and needles, generally follow the following principles:
Coordination with fabric characteristics can ensure the unity of shrinkage, heat resistance, wear resistance, durability, etc., to avoid wrinkles caused by excessive differences between thread and fabric. General soft thin material with thin thread, with small needle machine, hard thick material with thick thread, with large needle machine.
In coordination with sewing equipment, the flat sewing machine adopts left-turn sewing thread, which can be twisted to maintain the strength of sewing thread.
Fine cotton thread is used in the sewing machine, which is not easy to deform and wrinkle, and makes the chain stitch beautiful and comfortable. Double stitch should be selected with good extension. The crotch seam and shoulder seam should be made with firm stitches. Button eyeliner should be worn with durable stitches.
Special purpose clothing, such as stretch clothing needs stretch nylon thread, fire clothing should be heat resistant, flame retardant and waterproof treatment of high strength thread.