Sewing thread is an important auxiliary material for making shoes. Sewing thread plays the role of stitching, connecting, setting, and decorating the side and bottom of all kinds of shoes. The compatibility of sewing thread’s physical and chemical properties, product quality, and thread and sewing materials is closely related to the physical quality, appearance, performance, production efficiency, and economic benefits of footwear products. Although sewing thread is different in terms of usage and material of sewing, most cases, the performance of sewing thread is different. But the sewing line must meet two basic requirements: one is to form a seam, and two is to ensure that all kinds of wearing performance seam. Shoe sewing thread performance of total quality requirements is: there is enough sewing strength and abrasion fastness, service life, reliability and safety of the line should be higher than the upper surface of the material itself, heat resistance and good antistatic performance, reasonable twist and twist knot, can adapt to high-speed sewing, which can be good. From the actual production in China, the sewing thread should be selected from the following main aspects:
1. Cotton sewing thread. The cotton yarn has the advantages of high strength, low elongation, high heat resistance, stable sewing performance, good antistatic performance, and good general stitching property, but it has large washing shrinkage and poor color fastness. It is not suitable for sewing high-grade products.
2. Hemp sewing thread.Including the twine and linen two awns. Footwear mainly used awn twine, awn twine strength, and elongation, with little moisture quickly and wear resistance and high elongation of sesame line is generally about 5%, wet strength can increase 40 ~ 60%. It is mainly used for leather shoes and cloth shoes, such as the stitching and inner line of leather shoes, and the line at the bottom of the seam. The shoe soles, leather shoes, and welt seam.
3. Polyester sewing thread. Polyester sewing thread includes two types of polyester staple fiber line (terylene line) and polyester long thread (short polyester long silk thread). The common characteristics of the polyester lines are high strength, small washing shrinkage, elasticity, corrosion resistance, wear resistance, and weather resistance, good thermal stability and dimensional stability, good seams, and beautiful stitching threads.
4. Nylon sewing thread. Nylon sewing threads are nylon filament, with high strength, and abrasion resistance, good elasticity, high fatigue resistance, good corrosion resistance, good performance, and strong staining characteristics, and sewing performance is good, but there are great elongation, attached heat resistance, light resistance and resistance to yellowing performance is poor, the type of difference feel have the disadvantage of waxy sense and thermal shrinkage is large, mainly used in shoes, boots, sewing thread, sewing line, help stem money decorative stitching and sewing boots felt in the shovel line, etc.
5. Polyester cotton core wire polyester cotton core wire line is the high strength polyester filament as a core wire, the surface resistance of cotton yarn covered in polyester filament, the wire has high strength, good thermal stability, easy sewing, beautiful stitch, and other advantages, can adapt to the above 4500 RPM high-speed sewing requirements, but the price is high. At present, a small number of leather shoes and leather products are used.
6. Polyester cotton blended yarnAt present, the vast majority of the polyester and 35% cotton blended lines are 65%. Polyester cotton blended yarn has many advantages, such as high strength, good dimensional stability, good elasticity, less shrinkage, and strong durability. It is mainly used for the sewing of cloth shoes, and its use is similar to polyester yarn.