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US3843570A
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US
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Process for producing a porous material of polytetrafluoroethylene
Assignee: Kureha Corp
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Filing: 1974-01-25
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Granted: 1974-10-22
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Expires: 1994-01-25
Abstract
Abstract A porous material comprising polytetrafluoroethylene and having micropores is obtained by polymerizing a polymerizable monomer capable of forming a thermoplastic resin, which has been adsorbed or attached to fine particles of polytetrafluoroethylene, milling the resulting polymeric mixture of the polytetrafluoroethylene and the thermoplastic resin at a temperature higher than the softening point of the thermoplastic resin to form a shaped article and then removing therefrom said thermoplastic resin.
Inventors
- 👤 N Murayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:48
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/26; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
120 words
A PROCESS FOR PRODUCING A POROUS ARTICLE OF POLYTETRAFLUOROETHYLENE HAVING FINE AND UNIFORM PORES, WHICH COMPRISES POLYMERIZING AND POLYMERIZABLE MONOMER WHICH HAS BEEN ADSORBED OR ATTACHED TO FINE PARTICLES OF POLYTETRAFLUOROETHYLENE AND IS CAPABLE OF FORMING A THERMOPLASTIC RESIN, THE AMOUNT OF SAID POLYMERIZABLE MONOMER BEING AT LEAST 30 PERCENT BY WEIGHT BASED ON SAID POLYTETRAFLUOROETHYLENE AND THE THERA POLYMERIC MIXTURE OF POLYTETRAFLUOROETHYLENE AND THE THERMOPLASTIC RESIN FORMED BY POLYMERIZATION, MILLING SAID POLYMERIC MIXTURE AT A TEMPERATURE HIGHER THAN THE SOFTENING POINT OF THE THERMOPLASTIC RESIN TO FORM A SHAPED ARTICLE COMPRISING A FIBROUS MATERIAL HAVING A NETWORK STRUCTURE, AND THEREAFTER REMOVING SAID THERMOPLASTIC RESIN FROM SAID SHAPED ARTICLE TO PRODUCE A POROUS POLYTETRAFLUOROETHYLENE ARTICLE HAVING FINE AND UNIFORM PORES.
Claim 2
Dependent Claim
120 words
A PROCESS FOR PRODUCING A POROUS ARTICLE OF POLYTETRAFLUOROETHYLENE HAVING FINE AND UNIFORM PORES, WHICH COMPRISES POLYMERIZING AND POLYMERIZABLE MONOMER WHICH HAS BEEN ADSORBED OR ATTACHED TO FINE PARTICLES OF POLYTETRAFLUOROETHYLENE AND IS CAPABLE OF FORMING A THERMOPLASTIC RESIN, THE AMOUNT OF SAID POLYMERIZABLE MONOMER BEING AT LEAST 30 PERCENT BY WEIGHT BASED ON SAID POLYTETRAFLUOROETHYLENE AND THE THERA POLYMERIC MIXTURE OF POLYTETRAFLUOROETHYLENE AND THE THERMOPLASTIC RESIN FORMED BY POLYMERIZATION, MILLING SAID POLYMERIC MIXTURE AT A TEMPERATURE HIGHER THAN THE SOFTENING POINT OF THE THERMOPLASTIC RESIN TO FORM A SHAPED ARTICLE COMPRISING A FIBROUS MATERIAL HAVING A NETWORK STRUCTURE, AND THEREAFTER REMOVING SAID THERMOPLASTIC RESIN FROM SAID SHAPED ARTICLE TO PRODUCE A POROUS POLYTETRAFLUOROETHYLENE ARTICLE HAVING FINE AND UNIFORM PORES.
Claim 3
Dependent Claim
33 words
The process according to claim 1 wherein the polymerizable monomer capable of forming the thermoplastic resin is selected from the group consisting of methyl methacrylate, styrene, vinyl chloride, vinylidene chloride, and copolymers thereof.
Claim 4
Dependent Claim
29 words
The process according to claim 1 wherein the polymeric mixture is admixed with an additional synthetic resin such as polyvinyl chloride and then milled to form a shaped article.
Claim 5
Dependent Claim
36 words
The process according to claim 1 wherein the polymeric mixture admixed with a filler is milled to form a shaped article, the thermoplastic is removed from the shaped article and then the filler is removed therefrom.
Claim 6
Dependent Claim
20 words
The process according to claim 1 wherein the shaped article is extracted with a solvent to remove the thermoplastic resin.
Claim 7
Dependent Claim
38 words
The process according to claim 5 wherein said thermoplastic resin is poly (methyl methacrylate) and wherein said solvent is selected from the group consisting of benzene, toluene, ethylbenzene, chloroform, methyl ethyl ketone, acetone, tetrahydrofuran, tetrachloroethane, acetonitrile and butanone.
Claim 8
Dependent Claim
27 words
The process according to claim 5 wherein said thermoplastic resin is polystyrene and said solvent is selected from the groups consisting of benzene, toluene, tetrahydrofuran and chloroform.
Claim 9
Dependent Claim
29 words
The process according to claim 5 wherein said thermoplastic resin is polyvinyl chloride and said solvent is selected from the group consisting of tetrahydrofuran, cyclohexanone, nitrobenzene, dimethylsulfoxide and dimethylformamide.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |