A type of easy-to-dye porous modified polyester fibers and preparing method thereof are disclosed. The preparing method is using the modified polyester melt through a porous spinneret with FDY process; wherein the modified polyester is a product of an esterification and successive polycondensation reactions of an evenly mixed terephthalic acid, ethylene glycol, main chain silicated diol, 2,2,3,4,5,5-hexamethyl-3,4-hexanediol, and metal oxide doped Sb.sub.2O.sub.3 powder; wherein the main chain silicated diol is selected from the group consisting of dimethylsiloxane diol, dimethyldiphenyldisiloxane glycol and tetramethyldisiloxane diol. The structural formula of 2,2,3,4,5,5-hexamethyl-3,4-hexanediol is as follows:

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The dye uptake and the K/S value of the prepared easy-to-dye porous modified polyester fiber are high. This invention features a method with ease of application and a product with good dyeing performance and good quality.

A type of easy-to-dye porous modified polyester fibers and preparing method thereof are disclosed. The preparing method is using the modified polyester melt through a porous spinneret with FDY process; wherein the modified polyester is a product of an esterification and successive polycondensation reactions of an evenly mixed terephthalic acid, ethylene glycol, main chain silicated diol, 2,2,3,4,5,5-hexamethyl-3,4-hexanediol, and metal oxide doped Sb.sub.2O.sub.3 powder; wherein the main chain silicated diol is selected from the group consisting of dimethylsiloxane diol, dimethyldiphenyldisiloxane glycol and tetramethyldisiloxane diol. The structural formula of 2,2,3,4,5,5-hexamethyl-3,4-hexanediol is as follows:

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The dye uptake and the K/S value of the prepared easy-to-dye porous modified polyester fiber are high. This invention features a method with ease of application and a product with good dyeing performance and good quality.

Provided is a medical fabric that is thin, and has both high tear strength and low water permeability. The medical fabric is characterized in that multifilament yarns having a total fineness of 7-80 dtex are disposed in the warp and weft, the single yarn fineness of at least one of the multifilament yarns among the warp and weft is 0.5 dtex or less, the twist factor A of the weft is 50-2,000, the thickness is 10-90 μm, and the water permeability both before and after puncture by a needle is 300 cc/min/cm.sup.2 or less.

Provided is a medical fabric that is thin, and has both high tear strength and low water permeability. The medical fabric is characterized in that multifilament yarns having a total fineness of 7-80 dtex are disposed in the warp and weft, the single yarn fineness of at least one of the multifilament yarns among the warp and weft is 0.5 dtex or less, the twist factor A of the weft is 50-2,000, the thickness is 10-90 μm, and the water permeability both before and after puncture by a needle is 300 cc/min/cm.sup.2 or less.

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.

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.

An apparatus for making spunbonded nonwoven from continuous thermoplastic filaments has a spinneret for downwardly emitting the continuous filaments in a filament direction, a cooling chamber directly beneath the spinneret for receiving the filaments from the spinneret and cooling the spun filaments with cooling air and having relative to a longitudinally extending machine direction a pair of longitudinal sides extending parallel to the machine direction and a pair of transverse sides extending substantially perpendicular to the machine direction between the longitudinal sides. Respective air-supply manifolds on the transverse sides feed cooling air therefrom into the cooling chamber. The cooling air is extracted from the cooling chamber at the longitudinal sides. A stretcher directly beneath the cooling chamber receives and elongates the cooled filaments, and a device deposits the stretched filaments as a band and conveys the band off in the machine direction.

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%.

An apparatus for making spunbond from continuous thermoplastic filaments has a spinneret for spinning the continuous filaments and advancing them in a filament-travel direction, a cooler for cooling the filaments, a stretcher for stretching the filaments, a depositing device including a foraminous belt extending in a machine direction transverse to the filament-travel direction for deposition of the filaments as a nonwoven web and conveyance away from the stretcher, a diffusor between the stretcher and the foraminous belt so that filaments and primary air from the stretcher enter into the diffusor, and a suction device for extracting air through the foraminous belt at an unobstructed extraction region underneath the diffusor outlet and having a width b in a machine direction that is greater than a width B of the diffusor outlet. The diffusor forms upstream and downstream secondary air-inlet gaps at opposite ends through which secondary air is aspirated into the diffusor.