A type of polyester yarn for an industrial sewing thread and preparing method thereof are provided. The preparing method is composed of a viscosity enhancing by a solid state polycondensation and a melt spinning for a modified polyester, and the modified polyester is a product of esterification and polycondensation of evenly mixed terephthalic acid, ethylene glycol, tert-butyl branched dicarboxylic acid, trimethylsilyl branched diol and a doped Sb.sub.2O.sub.3 powder, wherein the tert-butyl branched dicarboxylic acid is selected from the group consisting of 5-tert-butyl-1,3-benzoic acid, 2-tert-butyl-1,6-hexanedioic acid, 3-tert-butyl-1,6-hexanedioic acid and 2,5-di-tert-butyl-1,6-hexanedioic acid. Moreover, the modified polyester is dispersed with a doped ZrO.sub.2 powder. An obtained fiber has an intrinsic viscosity drop of 23-28% when stored at 25° C. and R.H. 65% for 60 months.

A type of polyester yarn for an industrial sewing thread and preparing method thereof are provided. The preparing method is composed of a viscosity enhancing by a solid state polycondensation and a melt spinning for a modified polyester, and the modified polyester is a product of esterification and polycondensation of evenly mixed terephthalic acid, ethylene glycol, tert-butyl branched dicarboxylic acid, trimethylsilyl branched diol and a doped Sb.sub.2O.sub.3 powder, wherein the tert-butyl branched dicarboxylic acid is selected from the group consisting of 5-tert-butyl-1,3-benzoic acid, 2-tert-butyl-1,6-hexanedioic acid, 3-tert-butyl-1,6-hexanedioic acid and 2,5-di-tert-butyl-1,6-hexanedioic acid. Moreover, the modified polyester is dispersed with a doped ZrO.sub.2 powder. An obtained fiber has an intrinsic viscosity drop of 23-28% when stored at 25° C. and R.H. 65% for 60 months.

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 type of high-modulus-low-shrinkage activated PET industrial yarn and preparing method thereof are disclosed. The preparing method is to manufacture filament from a modified polyester, which is the product of the esterification and the successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol and tert-butyl branched heptanediol, through a series of processes composed of viscosity enhancing by solid state polycondensation, melting, metering, extruding, cooling, oiling, stretching, heat setting, relaxation heat-treating, oiling with activation oil, winding and pre-activation treatment. The relaxation heat-treating indicates passing the modified polyester yarns through a space with a certain temperature within 200-220° C. under a proper relaxation state; and the proper relaxation state means a 3.0-5.0% of overfeed for the winding. The improvement of activator efficiency by importing the tert-butyl branched diol into the polyester, together with the synergistic effect of heat setting temperature and high winding overfeed rate, will reduce the fiber thermal shrinkage.

Particular techniques involve a device for wetting multiple threads with a fluid, and a dosing pump which is connected to the wetting means by multiple conveying lines. The dosing pump has multiple conveying means for generating multiple dosing flows of the fluid and has multiple pump outlets, to which the delivery lines are connected. The conveying means are formed by at least one planetary gear set arranged between housing plates. To achieve, as far as possible, a uniform throughflow without a significant dead space volume, multiple planet gears of the planetary gear set are guided freely by a centering plate between adjacent housing plates. The planet gears of the planetary gear set have in each case one passage opening, which are connected by a channel system to a central pump inlet. It is thus possible to realize close fits and flushing of gaps.

Particular techniques involve a device for wetting multiple threads with a fluid, and a dosing pump which is connected to the wetting means by multiple conveying lines. The dosing pump has multiple conveying means for generating multiple dosing flows of the fluid and has multiple pump outlets, to which the delivery lines are connected. The conveying means are formed by at least one planetary gear set arranged between housing plates. To achieve, as far as possible, a uniform throughflow without a significant dead space volume, multiple planet gears of the planetary gear set are guided freely by a centering plate between adjacent housing plates. The planet gears of the planetary gear set have in each case one passage opening, which are connected by a channel system to a central pump inlet. It is thus possible to realize close fits and flushing of gaps.

A polyamide multifilament includes a polyamide resin and has a total fineness of 30.0 to 150.0 dtex, a tenacity of 7.5 to 10.0 cN/dtex, and an elongation at break of 15.0 to 35.0%. A method of producing the polyamide multifilament includes the steps of: providing polyamide chips; and making yarn using a method of direct spinning and drawing, wherein |ηa−ηb|<0.3 is satisfied, assuming that sulfuric acid relative viscosity of said polyamide chips is ηa, and that sulfuric acid relative viscosity of said polyamide multifilament made into yarn is ηb.

A polyamide multifilament includes a polyamide resin and has a total fineness of 30.0 to 150.0 dtex, a tenacity of 7.5 to 10.0 cN/dtex, and an elongation at break of 15.0 to 35.0%. A method of producing the polyamide multifilament includes the steps of: providing polyamide chips; and making yarn using a method of direct spinning and drawing, wherein |ηa−ηb|<0.3 is satisfied, assuming that sulfuric acid relative viscosity of said polyamide chips is ηa, and that sulfuric acid relative viscosity of said polyamide multifilament made into yarn is ηb.

Provided is a cut-resistant polyethylene yarn, and more particularly, a cut-resistant polyethylene yarn which allows manufacture of a product having excellent cut resistance and providing excellent wearability.