Patents Represented by Law Firm Toren, McGeady and Stager
  • Patent number: 4111810
    Abstract: Semipermeable membranes useful in reverse osmosis and a process of preparing them comprising deacetylating naturally occurring chitin to produce chitosan, making a film of chitosan salt from an acid diluted aqueous solution of the chitosan, converting the film of chitosan salt to a film of chitosan having free amino groups by neutralizing the acid groups, and then subjecting the film of chitosan to a chemical treatment with an organic acid, by which to convert the chitosan to the acetylated form, having a degree of acetylation from about 0.3 to 0.8, to produce the reverse osmotic membranes.The products have excellent chemical properties as well as mechanical strengths sufficient to withstand the pressure difference in the operating condition.
    Type: Grant
    Filed: March 16, 1977
    Date of Patent: September 5, 1978
    Assignee: Shin-Etsu Chemical Company
    Inventors: Shigeru Arai, Fumio Akiya