Abstract: The present invention relates to a method for separating and refining high purity 2,6-naphthalene dicarboxylic acid having an excellent color and purity of 99.9% or more by using crude 2,6-naphthalene dicarboxylic acid. And more particularly, the present invention relates to a method for separating and refining 2,6-naphthalene dicarboxylic acid, in which adjustment of pressure and temperature during multiple-step crystallization process enables controlling nucleation and the crystal growth rate, thereby allowing a particle size distribution and form to be controlled.

Abstract: The present invention relates to a process for preparing polyethylene naphthalate, comprising the steps of: esterifying 2,6-naphthalene dicarboxylic acid and ethylene glycol, or glycols using the two materials as major material to obtain prepolymer which comprises bis(beta-hydroxyethyl)naphthalate or low polymer as main material; and performing polycondensation reaction to thereby prepare polyethylene naphthalate. The process of the present invention has advantages of: enabling esterification with a low molar ratio of ethylene glycol to reduce reaction time, thereby increasing process efficiency; minimizing formation of side reaction products to improve properties; and preventing deterioration of the products by performing polycondensation at a low temperature to thereby obtain polyethylene naphthalate polymers of high quality.

Abstract: The present invention relates to a process for preparing polyketone with improved catalytic activity and intrinsic viscosity, and specifically a process for preparing polyketone, using a mixed solvent of 40 to 60 mol % acetic acid and 40 to 60 mol % water, as a liquid medium, and the precursor of palladium chloride-1,3-bis[di(methoxyphenyl)phosphino]propane, as a catalyst component.

Abstract: High-purity 2,6-dimethylnaphthalene is prepared by (1) subjecting a dimethylnaphthalene isomer mixture rich in 1,5-dimethylnaphthalene, high boiling point materials, unreacted 1,5-dimethyltetralin, and low boiling point materials, which are produced from a dehydrogenation reaction of 1,5-dimethyltetralin, to separation, using a distillation column; subjecting the dimethylnaphthalene mixture separated by the distillation column to liquid state isomerization in the presence of an isomerization catalyst; (3) a first crystallization (melt crystallization process) by cooling the product of liquid state isomerization with a refrigerant without a solvent to form crystals; and (4) a second crystallization (solution crystallization process) of mixing the crystals of the first crystallization step with a solvent to form crystals.

Abstract: The present invention relates to a method for achieving high purity separation and refinement by controlling morphology and particle size of 2,6-dimethylnaphthalene. And more particularly, the present invention relates to a method for obtaining high purity 2,6-dimethylnaphthalene crystals, in which crystallization is carried out with a solvent that enables the crystals to form a square-platy shape. During the process, crystallization variables such as, stirring speed, cooling speed, solvent and composition ratio, are adjusted to control morphology and particle size of 2,6-dimethylnaphthalene and to remove aggregation, thereby obtaining 2,6-dimethylnaphthalene crystals of high purity.

Abstract: Disclosed herein is a Polyester Fiber Having Excellent Light-Shielding and Flame Retardant Characteristic. The Polyester Fiber comprises: phosphorus-based flame retardant 0.05˜5% by weight, based on phosphorus atom; and inorganic particles having 0.05˜1 ?m average particle size 1-5% by weight, based on fiber weight. Further disclosed is Textile Goods prepared from the Polyester Fiber. The polyester fiber according to the present invention is prepared from polyester polymer having Intrinsic viscosity of 0.55˜0.75 dl/g and the Intrinsic viscosity difference of between the fiber and polymer (IV drop) is within 0.03 dl/g and it exhibits the excellent flame retardant and light shielding characteristic. Therefore, the polyester fiber can be applied to fiber for clothes, light shielding curtain for a car and blackout curtain for a house and theater.

Abstract: The present invention relates to disposable hygiene products such as a diaper or a sanitary napkin applying an elastic spandex fiber with high power retention. A polyurethane-based spandex fiber is produced by reacting an organic diisocyanate with a polymer diol to prepare a prepolymer, dissolving the prepolymer in an organic solvent, and reacting the resulting solution with a diamine and a monoamine. A disposable hygiene product having better functionality and wearing comfort is provided by using a spandex fiber as an elastic yarn, wherein the spandex fiber has power retention of 70% or more.

Abstract: The present invention relates to cellulose fiber containing 500 to 2000 of filaments and having homogeneous physical properties and the multi-filaments according to the present invention is characterized in that the strength and the breaking elongation of the multi-filaments are 4 to 9 g/d and 4 to 15%, respectively. In particular, the present invention is characterized in that each mono-filament selected 100 strands from every three part divided from multi-filaments has properties as following: (a) 3 to 9 g/d in average strength, 7 to 15% in average breaking elongation and 0.035 to 0.055 in by birefringence, (b) the differences of the above three parts are below 1.0 g/d in average strength, 1.5% in breaking elongation and 0.7 denier in denier, (c) the CV (%) (coefficient of variation) of the above three parts are below 10%, and (d) the birefringence differences of the above three parts are below 0.004.

Abstract: Disclosed herein is a process of producing high purity and high yield dimethylnaphthalene by dehydrogenating a dimethyltetralin isomer using a metal catalyst for dehydrogenation. The metal catalyst contains a carrier selected from alumina (Al2O3), silica (SiO2), a silica-alumina mixture and zeolite. The metal catalyst also contains 0.05 to 2.5% by weight of platinum (Pt), 0.1 to 3.0% by weight of tin (Sn) or indium (In), 0.5 to 15.0% by weight of at least one selected from the group consisting of potassium (K), magnesium (Mg) and cesium (Cs), 0.3 to 3.0% by weight of chlorine, and 0.01 to 3.0 % by weight of zinc (Zn) or gallium (Ga) as active components based on an element weight of the final catalyst.

Abstract: The present invention relates to cellulose fiber containing 500 to 2000 of filaments and having homogeneous physical properties and the multi-filaments according to the present invention is characterized in that the strength and the breaking elongation of the multi-filaments are 4 to 9 g/d and 4 to 15%, respectively. In particular, the present invention is characterized in that each mono-filament selected 100 strands from every three part divided from multi-filaments has properties as following: (a) 3 to 9 g/d in average strength, 7 to 15% in average breaking elongation and 0.035 to 0.055 in by birefringence, (b) the differences of the above three parts are below 1.0 g/d in average strength, 1.5% in breaking elongation and 0.7 denier in denier, (c) the CV (%) (coefficient of variation) of the above three parts are below 10%, and (d) the birefringence differences of the above three parts are below 0.004.

Abstract: A polyethylene terephthalate monofilament obtained by spinning a polyethylene terephthalate chip having an intrinsic viscosity of 0.8 to 1.3, which gives a stress-strain curve exhibiting an elongation of less than 2.5% at an initial stress of 2.0 g/d, with an initial modulus value of 80 to 160 g/d, an elongation of 7.5% or less in a stress range of from 2.0 g/d to 9.0 g/d, and an elongation of at least 2.0% or more in a stress range of from 10.0 g/d to the point of break, is provided.

Abstract: Disclosed is a method for purifying 2,6-naphthalenedicarboxylic acid (NDA) that is present in a solid state in a solution. According to the method, sintered metal membrane filtration units are used to efficiently separate and purify 2,6-naphthalenedicarboxylic acid separated after hydrogenation and crystallization in a continuous process. An apparatus for implementing the method is further provided.

Abstract: Disclosed herein are a process for the refinement of nitrogen trifluoride gas and an adsorbent therefor. A nitrogen trifluoride (NF3) gas including carbon tetrafluoride (CF4) as an impurity is permeated into a bed of zeolite 3A, 4A or 5A which undergoes ion exchange and impregnation with alkali earth metal and is thermally treated at 150 to 600° C. for 0.5 to 100 hours so as to be able to selectively adsorb nitrogen trifluoride onto the bed, followed by the desorption of the nitrogen trifluoride therefrom.

Abstract: The present invention provides a lyocell raw cord prepared from at least 2-ply lyocell multifilaments, which gives a stress-strain curve exhibiting that (a) the lyocell raw cord has an elongation of 1.5% or less at an initial stress of 1.0 g/d, and an initial modulus value of 50 to 100 g/d; (b) has an elongation of 7% or less in a stress region of 1.0 g/d to 4.0 g/d; and (c) has an elongation of 1% or more at a tensile strength of 4.0 g/d to the breaking point, as measured in the dried state. The lyocell raw cord prepared according to the present invention can be used as industrial fibers, in particular, fibers for tire cords.

Abstract: The present invention relates to a polyethylene terephthalate nanocomposite fiber with enhanced modulus, and specifically to a technique for preparing a PET nanocomposite fiber with excellent initial and high-temperature modulus, which comprises adding 1 to 4% by weight of a compound selected from the group consisting of C56H122O12Si7, C31H71NO12Si8n, C59H127NO12Si8, and C33H76N2O12Si8, each of which is an organic/inorganic hybrid nanocompound, based on the total weight of the polymers, to prepare a polyethylene terephthalate nanocomposite chip having 85 mol % or more of the ethylene terephthalate units and an intrinsic viscosity in the range of 0.50 to 1.20, and then melt-spinning and stretching the composite chip.

Abstract: A method for separating and purifying 2,6-dimethylnaphthalene, is provided in which 2,6-dimethylnaphthalene of high purity is obtained from a mixture of dimethylnaphthalene isomers with a high yield, by means of a combined process of column melt crystallization and sweating operation.

Abstract: Provided are a novel microorganism and a method for purifying 2,6-naphthalene dicarboxylic acid with high purity using the microorganism. The microorganism is Pseudomonas sp. Strain HN-72 isolated from soil and has the ability to convert 2-formyl-6-naphthoic acid contained as an impurity in a crude naphthalene dicarboxylic acid, which is an oxidation product of 2,6-dimethylnaphthalene, to 2,6-naphthalene dicarboxylic acid. The Pseudomonas sp. strain HN-72 has excellent effects in producing high-purity 2,6-naphthalene dicarboxylic acid in high yield.

Abstract: Disclosed is a 3-D crimp polyethylene terephthalate multifilament (BCF) having a stress-strain curve that (a) it elongates less than 5.0% when subjected to an initial stress of 1.0 g/d, (b) it has an initial modulus of 20 to 60 g/d, (c) it elongates at least 20% when subjected to a stress region of 1.0 to 2.5 g/d and (d) it elongates from a tensile strength of at least 3.0 g/d to the tensile strength at break. The BCF has improved physical properties such as excellent flame retardancy, high toughness, improved crimp uniformity and improved compressive elasticity modulus.

Abstract: A high strength polyamide fiber consisting of polyamide monofilaments each having a fineness of less than 4 denier and a stress-strain curve where (a) the monofilament elongates less than 5% when subjected to an initial stress of 1.0 g/d, (b) it elongates less than 12% when subjected to a middle stress of 4.5 g/d, and (c) it elongates more than 3% over a tensile strength range from a tensile strength of at least 9.0 d/g to the tensile strength at break of the monofilament, the elongation values being measured at ambient temperature.

Abstract: The present invention relates to a process for producing tetrahydrofuran polymer or tetrahydrofuran copolymer by using heteropolyacid catalyst, and more particularly, to a process for producing tetrahydrofuran polymer by using hydronium ion water having a pH of 5.5 or less as a reaction initiator in the initiation step.