Types of polyester filament

Polyester is an important variety of synthetic fiber, is the trade name of polyester fiber. It is based on refined terephthalic acid (PTA) or dimethyl terephthalate (DMT) and ethylene glycol (MEG) as raw materials, through esterification or transesterification and condensation polymerization reaction to prepare the forming polymer - polyethylene terephthalate (PET), through spinning and post-processing made of fiber. The so-called polyester filament is the length of more than a kilometer of silk, the filament is wound into a ball. According to the different production methods, polyester filament is generally divided into primary silk, stretch silk and deformed silk three categories.

raw yarn refers to the yarn spun by direct melt without stretching. According to the different spinning speed, it is generally divided into unstretched yarn(UDY), semi-pre-oriented yarn(MOY), pre-oriented yarn (POY) and high-oriented yarn (HOY).

1.Unstretched filament (UDY) : its fiber molecules have basically no orientation and are not crystallized. This kind of filament has low strength, large elongation and poor dimensional stability, so it cannot be directly applied in general.

2.2. Semi-oriented yarn (MOY) : the fiber molecules have a small amount of orientation, the orientation is higher than UDY, lower than pre-oriented silk, the structure of this kind of silk is still not stable enough to be directly applied.

3. Pre-oriented yarn (POY) : The fiber itself has been moderately stretched, has a certain orientation, there are a few micro-grains, but it is still lower than the requirements of finished silk. This kind of silk has low strength and high elongation, so it is still not suitable for direct processing of fabrics, but it can be combined with other fibers to produce composite silk to meet weaving needs, giving fabrics a special style.

3.High orientation silk (HOY) : It is made by one-step ultra-high speed spinning. The molecular orientation of the fiber is high, and the dyeing property of the fiber is good, but the elongation and thermal shrinkage of the fiber are large, which cannot meet the general consumption requirements.

Stretched yarn refers to the fiber obtained by moderate stretching of the fiber in the process of spinning. According to the different degree of stretching, it can be divided into stretched yarn (DY) and fully stretched silk (FDY).

1. Stretch yarn (DY) : It refers to the yarn made by low-speed stretching in the process of spinning, with a crystallinity of about 40%. This kind of silk is straight and smooth, closely arranged with each other, but with poor fluffiness.

2.Fully stretched yarn(FDY) : It refers to the yarn produced by one-step process of spinning and stretching. This kind of yarn has stable quality, less hair and broken end, and good dyeing uniformity, which is an ideal yarn for high-speed weaving processing. Its products are also widely used, the market capacity is larger, is one of the main raw materials of domestic home textiles, clothing fabrics.

Using the characteristics of synthetic fiber thermoplasticized deformation, under the action of machinery and heat, the straightened fiber into crimped fiber, called deformation filament, also known as deformation fiber. According to the different raw materials and processing technology, it can be divided into conventional deformation wire (TY), tensile deformation wire (DTY) and air deformation wire (ATY).

1. Conventional deformed yarn (TY) : It is the yarn produced by the three-step process of spinning, winding, stretching, twisting and false twisting, or the silk produced by the process of high-speed spinning and low-speed false twisting. It has certain elasticity and fluffiness and good dimensional stability.

2. Draw textured yarn (DTY) : Generally using POY as raw material, the low-elastic yarn obtained by one-step stretch deformation method has a certain elasticity, feel less soft than TY, but stable quality, strong elongation has met the requirements of use.

3. Air textured yarn (ATY) : It refers to the interlocking processing of the yarn bundle by air injection technology to form irregular twisted wire loops, so that the wire bundle has the shape of fluffy wool loops. Generally, FDY is used as raw material for production, and some products can also be produced with POY as raw material. The finished products are used together to produce home textile fabrics.