The Study Of Properties Of PTT/cotton Blended Yarns And Knitted Fabrics

The new polyester fiber- PTT (Poly Trimethylene Terephthalate)not only has the advantages of PET and PBT fiber, but offers the unique properties of elastic resilience and puffiness. Unlike spandex, PTT may be blended directly with other fibers, which makes spinning process sampler. In addition, PTT has excellent properties of softness, anti-creasing, good dimensional stability, chromatophile and shielding-even Y ray, therefore it is an ideal material for high-class dressesand factional fabrics, especially for knitting and weaving clothing because of its flexibility and softness.In the last ten years, PET/cotton fabric has been widely used. The property of blended fabric with low percent PET is no better than pure cotton fabric except hand feeling, so there is more with high percentPET at present in China. The new polyester fiber----PTT has excellentelastic recovery and yet its other properties are similar to PET. The PTT/cotton blended knitted fabric with low percent PTT has so good hand feeling that it is absolutely suitable for underwear.This paper studied the dyeing ability, elastic recovery of elongation, durability and water vapor permeability. The flexibility of PTT/cotton blended yarns of five different percentage (50/50, 35/65, 30/70, 25/75, 0/100) were tested. The testing results showed that the lower the PTT percentage, the higher the breaking strength, and the smaller the breaking elongation. When the yarns for one hour under the load of 25% of the breaking strength were stretched, the ranges of immediate elastic deformation reached to 57%~70%, the delayed deformation is about 5.3%~7.4% and the plastic strain is nearly 24.4%~36%. The higher the PTT percentage, the elastic resilience is better.This paper also analyzed the dyeing ability and elastic recovery of elongation of PTT/cotton blended knitted fabrics. The treatment process depends on depth of shade. Four dyeing programs were adopted such as one-bath process with disperse/direct dyestuff and disperse/active dyestuff and two-bath process with disperse/direct dyestuff and disperse/active dyestuff respectively. When dyeing color combinations and dark colors, two-bath process would be better, otherwise one-bath process is used.Besides chromatophile, the excellent elastic recovery of PTT fiber is another obvious advantage, therefore this paper mainly discussed the elastic recovery of elongation including one times and three times constant rate of elongation, as well as both the higher and lower ratio stretch and above-mentioned properties at the state of relaxation during wetting. The results proved that even if mixed with less PTT fiber, the blended fabrics get much better elasticity. The higher the content of PTT, the better the stability.Lastly some testing results affirmed that the PTT/Cotton blended knitted fabrics have good stability and water vapor permeability, this kind of fabrics are suitable for clothing.