Process for fabricating porous silicone product

• US 5,362,761 A
• Filed: 10/12/1993
• Issued: 11/08/1994
• Est. Priority Date: 07/11/1991
• Status: Expired due to Fees

• Current Assignee: Dow Corning Toray Company Limited (Dow, Inc.), Lignyte Co., Ltd.
• Original Assignee: Dow Corning Toray Company Limited (Dow, Inc.), Lignyte Co., Ltd.
• Inventors: Tanaka, Yoshiaki, Nakamura, Tatsuya, Uragami, Tadashi, Ozaki, Masaru
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US08/134,837
• Time in Patent Office: 392 Days
• Field of Search: 521/64, 521/61, 521/66, 521/154, 521/62, 521/63, 521/72
• US Class Current: 521/64
• CPC Class Codes: B01D 2323/14 Ageing features
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 67/0095 Drying
• CPC Class Codes: B01D 71/70 Polymers having silicon in the main chain, with or without sulfur, nitrogen, oxygen or carbon only
• CPC Class Codes: B01D 71/701 Polydimethylsiloxane
• CPC Class Codes: C08J 2201/0484 the liquid phase being aqueous
• CPC Class Codes: C08J 2383/04 Polysiloxanes
• CPC Class Codes: C08J 9/26 by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out

Abstract

A process of fabricating a porous silicone product utilizing a silicone emulsion capable of forming an elastomer by removal of water therefrom. The silicone emulsion comprises a water emulsion of an organopolysiloxane, a cross-linking agent, and a curing catalyst. The process comprises the steps of freezing the silicone emulsion, and drying the frozen silicone emulsion, whereby water is sublimed therefrom and the porous silicone product is obtained. The resulting porous silicone product is best utilized as a selective permeable membrane for separation of a liquid component from a liquid solution containing two or more liquid components.

Claims

1. A process for fabricating a porous silicone product by utilizing silicone emulsion capable of forming an elastomer by removal of water therefrom, said silicone emulsion comprising a water emulsion of an organopolysiloxane, a cross-linking agent, and a curing catalyst, said process comprising the steps of:

freezing said silicone emulsion; and

drying said frozen silicone emulsion, whereby water is sublimed therefrom and said porous silicone product is obtained.

2. A process as set forth in claim 1, wherein said silicone emulsion comprises:

a) a substantially straight chain organopolysiloxane having at least two silanol groups per one molecule;

b) a cross-linking agent selected from the group consisting of colloidal silica, silicate of alkali metal, hydrolyzable silane, and partially hydrolyzed condensate of hydrolyzable silane;

c) a curing catalyst;

d) an emulsifier; and

e) water.

3. A process as set forth in claim 1, wherein said freezing step is carried out after first cooling said silicone emulsion to such a temperature so as not to freeze said silicone emulsion.

4. A process as set forth in claim 2, wherein said freezing step is carried out after first cooling said silicone emulsion to such a temperature so as not to freeze said silicone emulsion.

5. A process as set forth in claim 1, wherein said porous silicone product is elastomeric.

6. A process as set forth in claim 1, wherein said porous silicone product has open cells.