Sewing threads are especially engineered threads to satisfy the requirements of the end product. The overall performance in terms of strength, durability and usefulness of the substrate depends on the sewing thread. Though the consumption of sewing thread is not more than 1% of the textile to be sewn, they are of considerable importance. These threads find the end use applications in almost every technical textile sector i.e. Indutech, Hometech, Meditech, Sporttech, Protech, Packtech, Clothtech etc. The present paper deals with the introduction to the different types of sewing threads along with their compositions, specifications and properties & also different end use applications.
History of sewing threads goes back to 2500 years ago when man used to make threads from animal hairs by rubbing and twisting. Later on jute, silk, linen, were used. Then cotton threads became so popular. Today is the era of synthetic threads where these threads are specially engineered to satisfy the functional requirements of the end products.
Processes and materials used for joining depend on the structure and properties of the substrate being joined and the properties required of the joint. Stitched seams predominates because the resulting seam is flexible, can be extensible can be unpicked and reformed and because stitching can be carried out on variety of substrates. Fusing, adhesive sealing and welding, the stitch less joining processes are limited to thermoplastic substrates or components. Stitch less joint is also tending to be stiff and inextensible, these properties narrowing further the range of applications in which they are appropriate.
Sewing threads may be defined as smooth, evenly spun, hard-twisted ply yarn, treated by the special finishing process to make it resistant to stresses in its passage through the needle eye and through material involved in seaming and stitching operation. It joins the different components of the substrate by forming a seam that primarily provides uniform stress transfer from one piece of substrate to another, thus preserving the overall integrity of the assembly.
Threads for the high temperature applications are required to withstand and hold the seams secure in their position in extreme temperature conditions between 260C- 1100C. Threads are usually made from glass, carbon, polytetrafluoroethylene, steel and aramide fibres. Polyesters, Polypropylene, Nylon6, Nylon6.6, are widely used for low temperature applications such as car upholstery, leather industry, packing like cement and fertilizer bags. Medical sutures are used for wound closure and are specially design and sterilized to fulfill the end applications.
The authors are associated with Wool Research Association, Thane