Patent US3812224A successfully refreshed from Google Patents.
US3812224A
Expired / Lapsed
US
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Process for the production of porous polymeric materials
Assignee: Polysar Ltd
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Filing: 1972-03-13
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Granted: 1974-05-21
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Expires: 1992-03-13
Abstract
Abstract A porous cellular composition is made by freezing a plastically deformable or pourable system containing a solid polymer and a compatible liquid which is capable of freezing to a crystalline state and then subliming the liquid. The composition contains interconnecting cells of not more than 1,000 microns in width and is suitable for the production of leather-like breathable sheets, filter elements and non-woven fabrics.
Inventors
- 👤 A Smith
- 👤 J Ingram
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:32
CPC Classifications
B; B29; B29C; B29C37/00; B29C37/0092; C; C08; C08J; C08J9/00; C08J9/26; B29C71/00; B29C71/0009; B29C2071/0036; B29C2791/00; B29C2791/004; B29C2791/006; B29K; B29K2105/00; B29K2105/04; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/13; Y10S264/17; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
42 words
The process according to claim 1 in which the compacted polymeric material comprises from about 0.5 to about 80 percent by weight of said polymeric resin and from about 20 to about 99.5 percent by weight of a solvent for said material.
Claim 2
Dependent Claim
29 words
The process according to claim 1 in which said solution during freezing is cooled to a temperature at least 10* C below the freezing temperature of said organic solvent.
Claim 3
Dependent Claim
86 words
The process according to claim 1 in which the compacted polymeric material comprising about 20-60 percent by weight of said polymeric resin having a second order transition temperature of not less than about 10* C and about 80-40 percent of said organic solvent for said resin is formed into a sheet and is subjected to a temperature and pressure below the triple point of said solvent whereby the solvent crystals sublime and a porous sheet is produced having pores of less than 500 microns in width.
Claim 4
Dependent Claim
32 words
The process according to claim 4 in which the sheet of compacted polymeric material has added thereto before freezing containing a fibrous reinforcement in order to form a reinforced porous polymeric sheet.
Claim 5
Dependent Claim
21 words
The process according to claim 1 in which the organic solvent is selected from the group consisting of benzene, cyclohexane, 1-4-dichlorobenzene.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |