US4517142A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing permeable polymeric membranes
Assignee: Yissum Research Development Co of Hebrew University of Jerusalem
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Filing: 1981-08-06
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Granted: 1985-05-14
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Expires: 2001-08-06
Abstract
Abstract The invention provides a method for producing permeable polymeric membranes comprising decomposing, in a polymeric matrix, molecular moieties, bound to the polymer or contained in compounds dispersed therein, into smaller, discrete, molecular units, whereby the smaller, discrete molecular units, which are formed, spontaneously leave the polymeric matrix and a membrane of defined permeation characteristics is obtained.
Inventors
- 👤 Avraham M. Baniel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:27
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0023; B01D67/003; C; C08; C08J; C08J5/00; C08J5/20; C08J5/22; C08J5/2206; C08J5/2218; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/18
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
101 words
In a method for producing permeable polymeric membranes by removal of substances contained in a polymeric mass resulting in the formation of pores, the improvement comprising providing a single phase thermoplastic polymeric mass consisting essentially of a polymeric backbone and having either (a) pendant groups having decomposable molecular units chemically bound to said polymeric backbone or (b) compounds having decomposable molecular units molecularly dispersed in said polymeric mass and inducing the decomposition of said molecular units into smaller, discrete molecular units which spontaneously leave the polymeric mass by diffusion without melting of the polymer mass and/or decomposition of said polymeric backbone.
Claim 2
Dependent Claim
101 words
In a method for producing permeable polymeric membranes by removal of substances contained in a polymeric mass resulting in the formation of pores, the improvement comprising providing a single phase thermoplastic polymeric mass consisting essentially of a polymeric backbone and having either (a) pendant groups having decomposable molecular units chemically bound to said polymeric backbone or (b) compounds having decomposable molecular units molecularly dispersed in said polymeric mass and inducing the decomposition of said molecular units into smaller, discrete molecular units which spontaneously leave the polymeric mass by diffusion without melting of the polymer mass and/or decomposition of said polymeric backbone.
Claim 3
Dependent Claim
61 words
A method for producing permeable polymeric membranes according to claim 1 wherein said polymeric mass consists of a selected polymer having molecular units contained in compounds molecularly dispersed therein said compounds being fully decomposable to form small discrete molecules which substantially all leave the polymeric mass by diffusion whereby a permeable membrane substantially consisting solely of the selected polymer is obtained.
Claim 4
Dependent Claim
40 words
A method for producing permeable polymeric membranes according to claim 1 wherein said decomposable molecular units are selected to decompose so that there remains at the sites of decomposition and after diffusion of said decomposed molecular units, chemically active groups.
Claim 5
Dependent Claim
18 words
A method for producing permeable polymeric membranes according to claim 3 wherein said chemically active groups are charged.
Claim 6
Dependent Claim
20 words
A method for producing permeable polymeric membranes according to claim 3 wherein said chemically active groups contain bound metal atoms.
Claim 7
Dependent Claim
18 words
A method for producing permeable polymeric membranes according to claim 3 wherein said active groups contain cryptand moieties.
Claim 8
Dependent Claim
40 words
A method according to claim 1 wherein said polymeric mass is a thermoplastic polymer, and includes the steps of shaping said polymeric mass into a desired membrane form prior to the step of inducing the decomposition of said molecular units.
Claim 9
Dependent Claim
22 words
A method for producing permeable polymeric membranes according to claim 7 wherein said decomposition is induced while maintaining said membrane under tension.
Claim 10
Dependent Claim
22 words
A method for producing permeable polymeric membranes according to claim 7 wherein said shaped polymeric mass is subjected to cross-linking after shaping.
Claim 11
Dependent Claim
24 words
The method of claim 7, wherein said thermoplastic polymer is selected from the group consisting of polyvinyl chloride, polyvinyl acetate, polysulfone, polyethylene and nitrocellulose.
Claim 12
Dependent Claim
62 words
The method of claim 7, wherein said decomposible molecular units are selected from the group consisting of t-butyl p-toluenesolfonate, di-t-Buadipate, N-t-butoxy carbonyl α amine lauric acid t-butylester, benzoyl peroxide, di-t-butyl malonate, poly-t-butyl methul metacrylate, t-butyloleate, t-butyl acetate, t-butyl chloroacetate, t-butyl orthocarbone, t-butyl orthosilicate, t-butoxycarbonyl methyl amide, t-butoyxcarbonyl ethylene diamide, t-butoxycarbonyl ethanol amide, ethylene glycol ester of t-butyoxylcarbonyl and glyceryl ester of t-butoxycarbonyl.
Claim 13
Dependent Claim
28 words
The method of claim 7, wherein said decomposition is induced by immersion of said membrane in concentrated hydrochloric acid at room temperature to 40° C., for 20-48 hours.
Claim 14
Dependent Claim
56 words
The method of claim 7, wherein said decomposition is induced by incorporating an acid catalyst selected from the group consisting of methyl sulfonic acid and p-toluene sulfonic acid in said polymeric mass shaping polymeric mass into a desired membrane form, and holding said membrane in an oven at about 45° C. for 2 to 4 hours.
Claim 15
Dependent Claim
22 words
The method of claim 7, wherein said decomposition is induced by irradiation of said membrane with an ultraviolet lamp for 2 hours.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-13 | 1988-11-12 | 1989-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-13 | 1992-11-12 | 1993-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-13 | 1996-11-12 | 1997-05-14 | $7700.00 | Window Closed / Lapsed |