Multi-strip fine danier polyester pre-extension yarn and its manufacturing method

Abstract

A multi-strip prestretched fine-denier polyester yarn is disclosed, which has excellent physical properties, uniform stretch stress and high dyeability. Its preparing process features use of radiation-type external blowing cooler and selective of beneficial spinning condition and hole arrangement on spinneret plate, and includes false twist, stretching twist and air blowing twist.

Description

technical field [0001] The invention relates to a method for manufacturing fine-denier polyester filaments, in particular to a method for manufacturing polyester fine-denier pre-stretched filaments and fine-denier stretched filaments. Background technique [0002] Polyester fiber has excellent mechanical properties and dyeability, and is low in cost, so it is the most commonly used among the three major synthetic fibers. In recent years, as the use of clothing materials has become more advanced, the handle and functional requirements of fabrics have been further improved. The single-filament denier (or single-fiber fineness, d.p.f) fine-denier synthetic fiber braids and fabrics obtained by melt spinning Its fleece products have been widely used as clothing materials. However, in its manufacturing process, the cooling effect of the polyester filaments after melting and extruding has a considerable impact on the physical properties and uniformity of the filaments. [0003] At...

AI Technical Summary

Problems solved by technology

However, during the production of the former in the spinning stage, as the denier per filament (d.p.f) becomes smaller, the number of holes in the spinneret needs to be increased. The cooling difference between the tow on the wind-receiving side and the tow farther away from the wind-receiving side is large, and the tow cannot be cooled uniformly. The physical properties of each single fiber are very different and the uniformity is poor; ) is less than 0.3den, the difference is more obvious, and it is impossible to provide pre-stretched filaments for production; and the latter needs to reduce the total output of polyester melt in order to maintain the number of holes in the spinneret, but this will make The residence time of the polyester melt in the melt pipeline increases, resulting in serious cracking of the polyester melt, a large amount of low polymers are produced, and the spinning condition is extremely deteriorated; Production in this way often reduces the output, and it is also easy to cause problems such as dyeing spots (unevenness) during dyeing after processing due to the difference in physical properties between the two strands of tow.

[0007] In addition, the radiation-type internal blowing device is difficult to adjust the cooling air, and the wind speed is too small to achieve sufficient cooling of the tow, resulting in a high long-term variation rate of uniformity (Uster halfinert value), and more serious cases of mutual adhesion between monofilaments However, smooth spinning is not possible; the wind speed is too high, and the cooling air in the opposite blowing direction interferes with each other, causing the tow to be unstable and the monofilaments to collide with each other, resulting in poor production conditions; It is also not conducive to the production of polyester fine denier pre-stretched yarn

[0008] Therefore, how to reduce the denier per filament (d.p.f) without sacrificing the output and at the same time make stable production of high-quality polyester fine denier pre-stretched yarn has become the subject that polyester synthetic fiber manufacturers are eager to break through. Patents US 5,288,553, US 5,145,623, US 5,407,621, and US 5,250,245 are based on the selection of ester pellets with a special range of melt viscosity, the selection of the hole diameter and hole length of the spinneret, and the limitation of the residence time of the polyester melt in the pipeline and other spinning conditions. The polyester fine denier pre-stretched yarn with a fineness of 0.2 to 0.8den, but the above-mentioned patent does not specify which cooling method is used, and the length of the windless belt is 2cm to (12× single filament denier -2 (d.p.f)) cm, because the length of the windless belt is too long, when increasing the number of holes on the spinneret per unit area, it still cannot achieve the expected uniformity. The long-term variation (Uster half inert value) is less than 0.3% and the thermal The requirement that the stress variation is less than 2%; Japanese Patent Laid-Open Publication No. 55-132708 discloses a polyester, polyamide, polyolefin filament stretching method (d.p.f) less than 0.3den. Control the viscosity of the molten body to be less than 950 poise when it is discharged, and keep the surrounding temperature below 200°C at 1 to 3 cm below the spinneret, and keep the cooling air within 10 cm below the spinneret at an angle of 5° to 85° upward from the horizontal direction. ° Angle cooling tow, this method can not stabilize the spinning because the surface of the spinneret is easily affected by the cooling wind, resulting in uneven temperature

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