Study On The Hand Of PTT Fabrics In Extremely Cold Environment

Thin and tight Fabrics made of PTT (Polytrimethylene terephthalate) filaments featured with a soft handle as an exaggerated style of clothing was developed in recent years. However, the current high market price of PTT fiber makes it obtain the achievement in the products, which can digest the high cost. According to our analysis, the senior down and outdoor fabrics market is able to meet the high cost of PTT fabrics. Currently, the senior down and outdoor fabrics market is monopolized by the nylon and polyester fabrics. The Particular advantages of performance are the key point that PTT fabric can be applied and expanded in this field. Playing the "price war" is not appropriate.The hand of the existing nylon and polyester fabric will be hard in the extremely cold environment, which affects the comfort of down jacket. The low glass transition temperature and soft hand of PTT fabrics may lead to low brittle transition temperature and soft hand in extremely cold environment, which is the main objective of the research paper. Around the objective, the article is studied in the following four aspects.(1)The bending properties of three types of high-density and thin fabrics made of PTT, PET and Nylon filaments were carried on. Bending stiffness B and bending hysteresis 2HB of the fabric were measured by KES in the standard temperature and humidity. The relevance of warp/weft bending rigidity Bj/Bw and bending hysteresis 2HB of the three types of fabrics were discussed as well as the law of interdependence and the reasons. The difference between the bending curve of Microfiber fabric and that of the common fabric was analyzed. According to the measured data and the weave density, single yarn bending stiffness was converted. This paper compared the bending stiffness of yarns of different materials and discussed the effects of filament or fiber number, denier per filaments (DPF), on bending stiffness of yarn & fabric by experimental data.(2)Shearing properties of three types of fabrics were studied. Shearing stiffness G and shearing hysteresis 2HG/2HG5 of the fabrics were measured by KES in the standard temperature and humidity. The relevance of warp/weft shearing rigidity Gj/Gw and shearing hysteresis 2HG/2HG5 of the three types of fabrics was discussed. The relevance of shear deformation angle y and shearing stiffness G was discussed in this paper. Meanwhile the study discovered the law of interdependence and analyzed the reasons.(3)A simple testing device on bending and shearing stiffness of fabrics in the extremely cold environment was built. The instruments of KES and FAST on the handle evaluation of fabrics are widely used. These two instruments can work in standard temperature and humidity, but cannot work in the extremely cold environment. Then a convenient and effective testing method was designed in this paper. The main purpose of the designed experiment was to test the bending and shear properties that affect the performance of these fabrics hand most importantly. A device, based on cantilever method, was built to test bending stiffness. The relevance of the bending stiffness measured by device and KES was discussed by comparative experiments in standard temperature and humidity. A device, based on bias extension approach, was built to test shearing stiffness. The load of bias extension load is 20cN/cm was derived from theoretical analysis and experimental of diagonal stretching, and the load make all fabrics are in shear stage with sufficient shear deformation meanwhile. The relevance of the Shear angle y and shearing stiffness measured by KES was discussed by comparative experiments in standard temperature and humidity.(4)Bending and shearing properties of fabrics were studied in the extremely cold environment. Generally, hand of synthetic fabric become more rigid at low temperature. In order to explore the ideal fabric for down jacket and winter clothes, the bending and shearing properties of fabrics made of PTT, PTT/PET, PET and Nylon were tested by the testing devices in 20℃,-5℃,-15℃,-25℃, respectively. The results showed that the hand of PET fabric was harder than that of PTT fabric. As the temperature decreased, the stiffness of PTT and PET fabrics increased slightly, but the stiffness of Nylon fabrics increased significantly. That is to say, the hand of Nylon fabrics hardened rapidly with the temperature decreased.