Abstract: Disclosed is an optical-modulation object, including birefringent island-in-the-sea yarns, whose island portions are grouped, based on two or more spinning cores, in a matrix. The optical-modulation object causes formation of an optical modulation interface between island portions and sea portions, thus maximizing optical modulation efficiency, as compared to conventional birefringent island-in-the-sea yarns.

Abstract: Disclosed is a liquid crystal display device, provided with an optical-modulation film including a matrix and birefringent island-in-the-sea yarns having two or more spinning cores arranged in the matrix to considerably reduce production costs and remarkably increase luminance. The optical-modulation film includes birefringent island-in-the-sea yarns whose island portions are grouped based on two or more spinning cores, present in the matrix, thus causing formation of optical modulation interfaces between the island portions and sea portions, thus maximizing optical modulation efficiency, as compared to conventional birefringent fibers.

Abstract: Disclosed is a luminance-enhanced film. The luminance-enhanced film includes an intermediate layer comprising a birefringent island-in-the-sea yarn and a sheet laminated on both sides of the intermediate layer, wherein the interface between the intermediate layer and the sheet has an air-gap area ratio of 5% or less, and is characterized in that it is substantially free of curling and does not contain bubbles, thus exhibiting considerably superior optical efficiency and adhesion force. A liquid crystal display utilizing the luminance-enhanced film also advantageously exhibits considerably improved luminance.

Abstract: Disclosed is a spinneret for preparing island-in-the-sea yarns, wherein island ingredient supply channels are partitioned into a plurality of groups in a discharge portion. The island-in-the-sea yarns prepared using the spinneret can prevent aggregation of island portions in the center thereof, although the number of island portions is 500 or more. Accordingly, island-in-the-sea yarns are considerably advantageous for the preparation of microfibers, since 500 or more island portions can be disposed in one island-in-the-sea yarn and fineness of island portions can thus be reduced. In addition, the island-in-the-sea yarns have an advantage of considerably reduced production costs, since 500 or more microfibers can be produced from one island-in-the-sea yarn. Furthermore, the island-in-the-sea yarns render a specific color according to the ratio of sea portions to island portions and diameter of fibers, without adding chromogenic compounds such as dyes, and are thus applicable to photochromic fibers.

Abstract: Disclosed is a luminance-enhanced film, including birefringent island-in-the-sea yarns which comprise island portions and sea portions, each composed of a specific material. Accordingly, unlike conventional stack-type luminance-enhanced films, the luminance-enhanced film of the present invention comprises birefringent island-in-the-sea yarn, as a layer, in the sheet, thus considerably improving luminance without forming a plurality of layers. In addition, several hundred layers are not laminated on one film and the film can be easily fabricated at considerably reduced costs. Furthermore, the luminance-enhanced film has considerably more birefringent interfaces, as compared to films fabricated by conventional methods wherein birefringent fibers are incorporated into sheets, thus considerably improving luminance-enhancement effects and being industrially applicable.

Abstract: Disclosed is a luminance-enhanced film, including birefringent island-in-the-sea yarns, whose island portions are grouped, based on two or more spinning cores, present in a sheet. The luminance-enhanced film causes formation of an optical modulation interface between island portions and sea portions, thus maximizing optical modulation efficiency, as compared to conventional birefringent island-in-the-sea yarns. The birefringent island-in-the-sea yarns of the present invention are free of aggregation of island portions in the center thereof, although the number of island portions is 500 or more. As a result, the birefringent island-in-the-sea yarns maximize an optical modulation interface area, and thus considerably improve optical modulation efficiency, as compared to conventional birefringent island-in-the-sea yarns including one spinning core.

Abstract: Disclosed is an optical-modulation object, including birefringent island-in-the-sea yarns, whose island portions are grouped, based on two or more spinning cores, in a matrix. The optical-modulation object causes formation of an optical modulation interface between island portions and sea portions, thus maximizing optical modulation efficiency, as compared to conventional birefringent island-in-the-sea yarns.

Abstract: A method of manufacturing a plastic container includes adding nano-sized silica particles to a saturated polyester in an amount of 20 ppm to 10% by weight during transesterification or esterification and polycondensing an aromatic dicarboxylic acid and ethylene glycol as starting materials. The silica particles have an average particle diameter of 3–100 nm. The saturated polyester is polyethyleneterephthalate.

Abstract: The present invention concerns a method for producing a foamed product based on aromatic polyester resin, wherein at least one of IPA, DEG, TEG and PEG is selected and copolymerized at the step of aromatic polyester polymerization to produce aromatic polyester resin with a low melting point whose melting point ranges 80 to 180?. The resin is then cross-linked by means of an organic peroxide cross-link agent, subject to melt mixing at a temperature ranging 80 to 180? and then foamed in order to produce a foamed product based on aromatic polyester resin of a low melting point, excellent in thermal resistance, foaming magnification, strength, etc. The aromatic polyester resin represented by polyethyleneterephthalate is known excellent in chemical properties such as chemical resistance, solvent resistance, weather resistance, etc., and physical properties such as thermal resistance, dimension stability, rigidity, gas barrier capability, etc.

Abstract: Disclosed is a method for preparing saturated polyester used in various molded products, such as films, synthetic fibers, vessels and housings. In particular, the method improves mechanical properties, including tensile strength or impact resistance, of saturated polyester. In DMT method or TPA method, the saturated polyester is synthesized through transesterification or esterification and polycondensation, in which metal compounds, such as metal acetate compounds, metal hydroxides, and metal oxides, are added in the larger amounts upon synthesis, and thus crystalline internal grains are formed, thereby improving the mechanical properties. As such, the metal compound can be used alone or in combination with a phosphorous-based compound.

Abstract: A method for preparing polyester fibers whose water absorbency is comparable to that of natural fibers in which, at a suitable addition time from polyester polymerization to a stage prior to spinning; hydrophilic inorganic particles such as calcium oxide particles, magnesium oxide particles, and manganese oxide particles are added at an amount of 0.01-50 weight % based on the total weight of the fibers. This method enables polyester fibers to have superior water absorbency as well as excellent physical properties. As the inorganic particles are low-priced, this helps to keep down the total cost of producing the fibers.