Kolon Industries, Inc.

Saehan Industries Incorporated

Saekan Industries Incorporation

Young Seo Yoon

Ja-Young Koo

Chang Won Park

Nowon Kim

Jong-Eun Kim

Jong Han Kim

Disclosed is a process for preparing polyurethane particulate and polyurethane particulate prepared therefrom. The polyurethane particulate has properties such that it is easy to control to a spherical form, the polyurethane particulate can be prepared in a desired particle size, the color thereof is stably exhibited, a washing process thereof is easy because almost no foam is generated in the washing process, and the preparation cost can be lowered because the particles do not lump and a separate grinding process is not needed, by using an inorganic suspension stabilizer in the manufacture process of the polyurethane particulate.

Process for preparing polyurethane particulate and polyurethane particulate prepared therefrom

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 amine in the form of 2 wt % of meta-phenylenediamine (MPD), (ii) a polar solvent in the form of 0.3 wt % 2-ethyl-1,3-hexanediol (EHD), and (iii) an amine salt-forming combination of 2.3 wt % camphorsulfonic acid (CSA) and 1.1 wt % triethylamine (TEA). 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 heated at 90&deg; C. for about 3.5 minutes and then rinsed in a 0.2% Na CO aqueous solution at room temperature. The resultant membrane exhibits a flux of 47.9 gfd and a salt rejection of 97.6% when used at 225 psi for an aqueous solution containing 2000 ppm of NaCl. In another embodiment, the aqueous solution contains (i) a polyfunctional amine in the form of 2 wt % of MPD, (ii) a combination of polar solvents in the form of 0.3 wt % of EHD and 2 wt % of dimethyl sulfoxide, and (iii) an amine salt-forming combination of 1 wt % of 1,1,3,3-tetramethylguanidine and 1.6 wt % toluene sulfonic acid. The resultant membrane exhibits a flux of 63.7 gfd and a salt rejection of 90.8% when used at 225 psi for an aqueous solution containing 2000 ppm of NaCl.

Composite polyamide reverse osmosis membrane and method of producing the same

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 2 wt % of meta-phenylenediamine (MPD), 1 wt % 1,4-diazabicyclo[2,2,2]octane (DABCO) and 0.85 wt % methanesulfonic acid (MSA). 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 heated at 90.degree. C. for about 3.5 minutes and then rinsed in a basic aqueous solution at 40-60.degree. C. for 30 minutes. The resultant membrane exhibits a flux of 32.3 gfd and a salt rejection of 97.0% when used at 225 psi for an aqueous solution containing 2000 ppm of NaCl.

Composite polyamide reverse osmosis membrane and method of producing the

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Seoul, South Korea

Young Seo Yoon