The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 23, 1999
Filed:
Jul. 02, 1996
Nitto Denko Corp., Osaka, JP;
Abstract
A composite reverse osmosis membrane has a polyamide type skin layer whose specific surface area ranges from 3 to 1000. The composite reverse osmosis membrane of this invention is superior in the salt rejection property and water permeability. The composite reverse osmosis membrane comprises a negatively-charged crosslinked polyamide type skin layer obtained by reacting a compound having polyfunctional amino groups and a polyfunctional acid halide compound having polyfunctional acid halide groups, and a microporous support to support the skin layer. The specific surface area of the skin layer is at least 3. A first stage of reverse osmosis treatment is carried out in a membrane module using this composite reverse osmosis membrane. The skin layer can be coated with a layer of an organic polymer having positively-charged groups e.g. polyethyleneimine in order to be used as another membrane module. The organic polymer of this case is crosslinked, for example, by glutaraldehyde. The layer which is crosslink-coated on its surface area is a composite reverse osmosis membrane excellent in desalination of mineral salt in a low-concentration region and removal of cationic organic materials.