Development Of PTT Weft Knitted Fabrics And Analysis Of Their Performances

PIT (Polytrimethylene Terephthalate) is a new product of aromatic polyesters. PIT overcomes the rigidity of PET and suppleness of PBT, and combines the advantages of polyester and polyamide, especially better elastic recovery and easier dyeing, focuses of fibers and materials field. Therefore, many countries have entitled PTT to one of the new-developed fibers in twenty-first century.At present, elastic yarns and fabrics occupied an important position in the world textile industry. In the fifties of twentieth century, Du Pont Company firstly industrialized the process of the new fiber-LYCRA, after that, this new-generated elastic fiber has wider uses. However, the complex machines and technologies, high cost materials, and serious pollution blocked the producing scale and LYCRA could not meet the demands of markets. Taking into account the convenience of procedure and lower cost, people have researched and developed the modified polyester and polyether forms, rather than the expensive polyurethane elastic fibers.It is easier to knit the fabrics with the PTT filaments. Generally, it is possible to get the power stretch fabrics of interlock stitch by controlling appropriate stitch density and yarn count. During the knitting procedure, PTT does not need to be made the core-spun yarns and can be used as separate elastic yarns, thus the processing is shortened. Owing to the zigzag macromolecular structure and lower glass transition temperature,coloration of PIT is easier than PET at 110, the best dyeing temperature for PIT. Meanwhile, comfort, ease care and durability, good impact strength, high elastic recovery and soft hand meet the demands of textile markets, so PTT fabrics are suitable to make swimming coats, underwear and top grade costumes. Under these conditions, the successful outcomes of this research paper will show a great benefit in technology and economic value.Based on so advantageous performance, how to show the differences between PTT and other elastic fibers in the knitting fabrics? In this paper, a large variety of products, including suede, warm- keeping fabrics, pure PTT fabrics (interlock and flat stitch), and some interweaved fabrics were developed. Take warm-keeping fabrics as an example, are worked by the pre-process, dyeing and heat-set techniques, which show the general technical lines and ways of PTT knitting fabrics.After finishing, all kinds of fabrics' performances were tested. By the experiments of the same and different elongation stretches and repeated stretches, the excellent elastic recovery ability of pure PTT knitting fabrics and improvement of resilience of the interweaved fabrics were proved owing to the addition of PTT. By testing the folded recovery angles and bend-rigidity, bend performances of PTT fabrics and their excellent folded recovery ability, soft hand and comfort were analyzed and proved. In other performances, such as, drapability, resistant hair, resistant abrasion and elongation, etc, PTT knitting fabrics also exhibit their own advantages.After a series of experiments and tests, including the mechanics, elastic recovery and bend performances, etc, some detailed describing for PTT weft fabrics from macroscopical angles were identified, and theirperformances in many aspects, products' adaptability, supply a stable foundation of developing and the usage of this fiber in the near future were also given in this paper.