Abstract: A selective membrane having a high fouling resistance. In one embodiment, the selective membrane is a composite polyamide reverse osmosis membrane in which a hydrophilic coating has been applied to the polyamide layer of the membrane, the hydrophilic coating being made by (i) applying to the membrane a quantity of a polyfunctional epoxy compound, the polyfunctional epoxy compound comprising at least two epoxy groups, and (ii) then, cross-linking the polyfunctional epoxy compound in such a manner as to yield a water-insoluble polymer.

Abstract: A domestic nanofiltration membrane based water purifier without a storage tank. The water purifier according to the present invention uses a nanofiltration membrane filter as a main filtering section and does not have a storage tank for containment of purified water. Although conventional reverse osmosis membrane based water purification systems provide good quality water, they have problems in that installation of the storage tanks due to insufficient flow rate results in the increased volumes of water purifiers, and at the same time, secondary pollution may be caused by microorganism propagation upon prolonged storage. In this regard, the present invention provides a domestic nanofiltration membrane based water purifier without a storage tank, in which a nanofiltration membrane filter with a pore size of approximately 0.1 to 10 nm is used as a main filtering section.

Abstract: A reverse osmosis membrane having excellent antifouling property, which is advantageous in terms of fundamental prevention of fouling generated by inorganic crystalloids, organic contaminants, and microorganisms, and a method for preparing the same. The membrane can be manufactured by hydrolyzing a titanium compound in an acidic aqueous solution to produce TiO2 particles of nano scale; dispersing the produced TiO2 particles in an acidic aqueous solution of pH 1-6 or an alkaline aqueous solution of pH 9-13 to yield a stable TiO2 dispersed solution; and immersing a reverse osmosis membrane prepared by a known method in the TiO2 dispersed solution to incorporate TiO2 into the membrane.

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 polyamic acid and polyimide of three-dimensional molecular structure such that these polymers are superior in adhesive strength and high-temperature stability while maintaining their inherent thermal resistance and mechanical properties, and thus can be effectively used as an adhesive material for high temperature adhesive tapes suitable for semiconductor assembly.

Abstract: An adhesive tape which can bond electronic parts at the environs of a lead frame, such as leads, diepads and radiant plate semiconductor chips, to each other and is superior in adhesiveness, thermal resistance and electrical properties. The adhesive tape is produced by coating on one side or both sides of a thermal resistant film an adhesive composition including an acryl resin, a mixed epoxy resin of a bisphenol A-type epoxy resin and a cresol novolak epoxy or a phenol novolak epoxy resin, a maleimide compound containing at least two intramolecular maleimide groups, an aromatic diamine compound, an epoxy-containing liquid silicon resin and an organic or inorganic filler and drying it.

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.

Abstract: A method for preparing polyamic acid and polyimide, which is suitable for use in adhesives or adhesive tapes for electronic parts. The polymers have such three-dimensional molecular structures that a significant improvement can be brought about in solvent solubility, thermal resistance, mechanical properties, and adhesive properties onto various substrates. The polyamic acid is prepared by reacting at least one tetracarboxylic dianhydride, at least one aromatic diamine, at least one diamine with a siloxane structure, represented by the following general formula I, and at least one polyamino compound represented by the following general formula II or III. The polyamic acid is converted into polyimide through thermal or chemical imidization.

Abstract: A composite polyamide reverse osmosis membrane and method of producing same. In one embodiment, the membrane is made by coating a porous polysulfone support for about 40 seconds with an aqueous solution containing (i) a polyfunctional primary or secondary amine in the form of 1.6 wt. % of meta-phenylenediamine (MPD), (ii) a polyfunctional tertiary amine in the form of 0.4 wt. % N,N,N′,N′-tetramethyl-1,6-hexanediamine (TMHD), and (iii) a polar solvent in the form of 0.2 wt. % 2-ethyl-1,3-hexanediol (EHD). Next, the excess aqueous solution is removed, and the coated support is dipped for about 1 minute in a 0.1 wt. % organic solvent solution of trimesoyl chloride (TMC) in a mixture of alkanes having from 8 to 12 carbon atoms. After draining the organic solvent solution off, the resulting composite membrane is air dried at room temperature for about 1 minute and then rinsed in a 0.2% Na2CO3 aqueous solution for 30 minutes at room temperature. The resultant membrane exhibits a flux of 46.

Abstract: Disclosed is a method for the preparation of 3-(hydroxyphenylphosphinyl)-propanoic acid which is commonly used as a flame retardant for polyester resins. The preparation of 3-(hydroxyphenylphosphinyl)-propanoic acid is attained by the condensation of phenylphosphonous dichloride and acrylic acid and the hydrolysis of the condensate. In the condensation, the mole ratio of phenylphosphonous dichloride to acrylic acid is within the range of 1:1.1 to 1:1.25. Under a pressure of greater than 1 atm, acrylic acid is added at 65.about.110.degree.C. at an amount more by 10.about.25 mole % than that of phenylphosphonous dichloride and the condensation is carried out at a temperature of 70.about.100.degree. C. under at greater than 1 atm, to produce 3-(hydroxyphenylphosphinyl)-propanoic acid at high yields with desired color.

Abstract: A method of producing an adhesive tape which can bond electronic parts at the environs of a lead frame, such as leads, diepads and radiant plates, semiconductor chips, to each other and which is superior in adhesiveness, thermal resistance and electrical properties. The adhesive tape is produced by coating on one side or both sides of a thermally resistant film an adhesive composition comprising a carboxylic group-containing acrylonitrile-butadiene copolymer ranging, in weight average molecular weight, from 5,000 to 10,000 with an acrylonitrile content of 5-50 weight %, a mixed epoxy resin selected from a set of bisphenol A-type epoxy and cresol novolak epoxy and a set of bisphenol A-type epoxy and phenol novolak epoxy, a compound having at least two intramolecular maleimide groups, an aromatic diamine compound, an epoxy-containing liquid silicon resin, a filler and a solvent and drying it.

Abstract: A composite polyamide reverse osmosis membrane and method of producing same. In a preferred embodiment, the membrane is made by coating a porous polysulfone support for about 1 minute with an aqueous solution containing 2 wt % m-phenylenediamine (MPD), 2 wt % 2-butoxyethanol and 2 wt % propylene glycol. Next, the excess MPD solution is removed, and the coated support is dipped for about 1 minute in 0.1 wt % organic solvent solution of trimesoyl chloride (TMC) in a mixture of alkanes having from 8 to 12 carbon atoms. After draining the TMC solution off, the resulting composite membrane is air dried at room temperature to 40.degree. C. for about 1 minute and then rinsed in a basic aqueous solution at 40-60.degree. C. for 1 to 30 minutes. The resultant membrane exhibits a flux of 27.5 gfd and a salt rejection of 98.2% when used at 225 psi for an aqueous solution containing 2000 ppm of NaCl.