A method includes charging PET bottle flakes having particular characteristics as a raw material into a crystallizer to generate a crystalline version thereof, drying the crystalline version with dehumidified air at a temperature of 160-180° C. and with a dew point of −40° C. to bring down a moisture level thereof below 100 ppm, melting the dried crystalline version through an extruder configured to have a temperature therein maintained at 285-295° C., and feeding the melted raw material into a spin beam. The method also includes generating, through a spinneret, a number of filaments based on extruding, through the spinneret, the melted raw material fed into the spin beam, forming a yarn based on combining the number of filaments, and winding the formed yarn to generate a spool of Partially Oriented Yarn (POY) configured to be utilized as another raw material to generate a Draw Texturized Yarn (DTY).

A method for improving the quality of a polyester industrial yarn is provided. First, in the cooling process of preparing a polyester industrial yarn prepared by polyester spinning, the longitudinal height is kept unchanged, and the cross-sectional area of the slow cooling chamber is enlarged. The chamber maintains the surface temperature of the spinneret by means of heat preservation, and then uses an oil agent containing 67.30-85.58 wt % crown ether in the oiling process of polyester industrial yarn prepared by polyester spinning. Enlarging the cross-sectional area of the slow-cooling chamber refers to the cross section of the slow cooling chamber is changed from a circular shape to a rectangular shape while keeping the spinneret connected to the slow cooling chamber unchanged. The cleaning cycle of the spinneret is prolonged by 35-45%, the full package rate of polyester industrial yarn is larger than 99%.

A method for improving the quality of a polyester industrial yarn is provided. First, in the cooling process of preparing a polyester industrial yarn prepared by polyester spinning, the longitudinal height is kept unchanged, and the cross-sectional area of the slow cooling chamber is enlarged. The chamber maintains the surface temperature of the spinneret by means of heat preservation, and then uses an oil agent containing 67.30-85.58 wt % crown ether in the oiling process of polyester industrial yarn prepared by polyester spinning. Enlarging the cross-sectional area of the slow-cooling chamber refers to the cross section of the slow cooling chamber is changed from a circular shape to a rectangular shape while keeping the spinneret connected to the slow cooling chamber unchanged. The cleaning cycle of the spinneret is prolonged by 35-45%, the full package rate of polyester industrial yarn is larger than 99%.

A method for tuning characteristics of a polyamide nanofiber nonwoven comprising the step of targeting a specific average nanofiber diameter and/or a specific relative viscosity for the polyamide nanofiber nonwoven. The specific average nanofiber diameter is within a range from 100 nm to 1000 nm and/or the specific relative viscosity is within a range from 5 to 75, e.g., from 15 to 50. The process further comprises the steps of extruding a polyamide composition having a moisture content with a pressurized gas through a fiber forming channel having a channel temperature to form the polyamide nanofiber nonwoven having the target average nanofiber diameter and/or relative viscosity and controlling the moisture content, the pressure of pressurized gas, and/or the channel temperature based on the specific average nanofiber diameter and/or the specific relative viscosity.

A method for tuning characteristics of a polyamide nanofiber nonwoven comprising the step of targeting a specific average nanofiber diameter and/or a specific relative viscosity for the polyamide nanofiber nonwoven. The specific average nanofiber diameter is within a range from 100 nm to 1000 nm and/or the specific relative viscosity is within a range from 5 to 75, e.g., from 15 to 50. The process further comprises the steps of extruding a polyamide composition having a moisture content with a pressurized gas through a fiber forming channel having a channel temperature to form the polyamide nanofiber nonwoven having the target average nanofiber diameter and/or relative viscosity and controlling the moisture content, the pressure of pressurized gas, and/or the channel temperature based on the specific average nanofiber diameter and/or the specific relative viscosity.

A low-shrinkage polyester industrial yarn and a preparation method thereof are provided. The preparation method includes the following steps: subjecting the modified polyester to polycondensation, melting, measuring, extruding, cooling, oiling, stretching, heat setting and winding, wherein the content of the crown ether in the oil agent is 67.30-85.58 wt %. The material of the prepared low shrinkage polyester industrial yarn is a modified polyester, the molecular chain of the modified polyester includes a terephthalic acid segment, an ethylene glycol segment, and a branched diol segment, and the structural formula of the branched diol is as follows: ##STR00001## Wherein R.sub.1 and R.sub.2 are each independently selected from a linear alkylene group having 1-3 carbon atoms, R.sub.3 is selected from an alkyl group having 1-5 carbon atoms, and R.sub.4 is selected from an alkyl group consisting of 2-5 carbon atoms.

A low-shrinkage polyester industrial yarn and a preparation method thereof are provided. The preparation method includes the following steps: subjecting the modified polyester to polycondensation, melting, measuring, extruding, cooling, oiling, stretching, heat setting and winding, wherein the content of the crown ether in the oil agent is 67.30-85.58 wt %. The material of the prepared low shrinkage polyester industrial yarn is a modified polyester, the molecular chain of the modified polyester includes a terephthalic acid segment, an ethylene glycol segment, and a branched diol segment, and the structural formula of the branched diol is as follows: ##STR00001## Wherein R.sub.1 and R.sub.2 are each independently selected from a linear alkylene group having 1-3 carbon atoms, R.sub.3 is selected from an alkyl group having 1-5 carbon atoms, and R.sub.4 is selected from an alkyl group consisting of 2-5 carbon atoms.

A thermal-moisture comfortable polyester FDY for summer use and a preparation method thereof are provided. The FDY is made of matting agents dispersed polyester via the steps of spinning melt metering, extruding via the compositional spinneret, cooling, oiling, drawing, heat setting and winding. The woven fabrics manufactured with the FDY possess a wicking height and an evaporation rate of larger than or equal to 135 mm and 0.22 g/h, respectively. The compositional spinneret is simultaneously provided with cruciform orifices and circular orifices, and the length ratio of cruciform orifice to circular orifice is equal to the product of their equivalent diameter ratio and a coefficient K, here equivalent diameter is the ratio of orifice cross-section area to its circumference and K ranges from 0.97 to 1.03, and the oiling involves the oiling agent containing 67.30-85.58 wt % of crown ether.

A thermal-moisture comfortable polyester FDY for summer use and a preparation method thereof are provided. The FDY is made of matting agents dispersed polyester via the steps of spinning melt metering, extruding via the compositional spinneret, cooling, oiling, drawing, heat setting and winding. The woven fabrics manufactured with the FDY possess a wicking height and an evaporation rate of larger than or equal to 135 mm and 0.22 g/h, respectively. The compositional spinneret is simultaneously provided with cruciform orifices and circular orifices, and the length ratio of cruciform orifice to circular orifice is equal to the product of their equivalent diameter ratio and a coefficient K, here equivalent diameter is the ratio of orifice cross-section area to its circumference and K ranges from 0.97 to 1.03, and the oiling involves the oiling agent containing 67.30-85.58 wt % of crown ether.

The present invention relates to a method for manufacturing a wholly aromatic liquid-crystalline polyester fiber with enhanced spinnability, and more specifically, to a method for manufacturing a wholly aromatic liquid-crystalline polyester fiber including: pelletizing a resin manufactured by adding 1.08 equivalents to 1.12 equivalents of acetic anhydride to raw material monomers including hydroxy benzoic acid, hydroxy naphthoic acid, biphenol, terephthalic acid, and isophthalic acid, followed by solid-phase polycondensation, and melt-spinning under oil conditions in which winding-up improving oil is diluted to 0.5% to 2% and silicone spinning oil for high temperature is diluted to 0.5% to 2%, respectively, with water as a solvent.