US5684055A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semi-continuous production of solid state polymeric foams
Assignee: WASHINGTON, University of
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Filing: 1994-12-13
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Granted: 1997-11-04
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Expires: 2014-12-13
Abstract
Abstract The present invention provides a method for the semi-continuous production of microcellular foam articles. In a preferred embodiment, a roll of polymer sheet is provided with a gas channelling means interleaved between the layers of polymer. The roll is exposed to a non-reacting gas at elevated pressure for a period of time sufficient to achieve a desired concentration of gas within the polymer. The saturated polymer sheet is then separated from the gas channelling means and bubble nucleation and growth is initiated by heating the polymer sheet. After foaming, bubble nucleation and growth is quenched by cooling the foamed polymer sheet.
Inventors
- 👤 Vipin Kumar
- 👤 Henry G. Schirmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 00:34
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/3442; B29C44/3446; B29C44/3453; B29C44/3469; B29C44/348; C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/122; C08J9/34; C08J2201/00; C08J2201/02; C08J2201/032; C08J2203/00; C08J2203/06; C08J2205/00; C08J2205/04; C08J2205/044; C08J2205/052; C08J2325/00; C08J2325/02; C08J2325/04; C08J2325/06; C08J2327/00; C08J2327/02; C08J2327/04; C08J2327/06; C08J2333/00; C08J2333/04; C08J2333/06; C08J2333/10; C08J2333/12; C08J2355/00; C08J2355/02; C08J2367/00; C08J2367/02; C08J2369/00; Y; Y10; Y10S; Y10S264/00; Y10S264/13; Y10S264/83
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
96 words
A method for foaming polymeric materials, comprising the steps of: (a) interleaving an article of polymeric material with a gas channeling means; (b) exposing the interleaved article at elevated pressure to a non-reacting gas which is soluble in the polymer for a time sufficient to achieve a desired concentration of gas within the polymer, thereby forming an exposed polymeric article which is at least partially gas-saturated; (c) separating the exposed polymer article from the interleaved gas channelling means; and (d) heating the exposed polymer article sufficiently to initiate bubble nucleation and to achieve desired bubble growth.
Claim 2
Independent Claim
96 words
A method for foaming polymeric materials, comprising the steps of: (a) interleaving an article of polymeric material with a gas channeling means; (b) exposing the interleaved article at elevated pressure to a non-reacting gas which is soluble in the polymer for a time sufficient to achieve a desired concentration of gas within the polymer, thereby forming an exposed polymeric article which is at least partially gas-saturated; (c) separating the exposed polymer article from the interleaved gas channelling means; and (d) heating the exposed polymer article sufficiently to initiate bubble nucleation and to achieve desired bubble growth.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein a plurality of articles are interleaved with gas channeling means.
Claim 4
Dependent Claim
20 words
The method of claim 1 or 2 wherein the polymeric article is a continuous sheet folded in a festooned manner.
Claim 5
Dependent Claim
17 words
The method of claim 1 or 2 wherein the polymeric article is a stack of polymeric sheets.
Claim 6
Dependent Claim
17 words
The method of claim 1 or 2 wherein the polymeric article is a roll of polymeric material.
Claim 7
Dependent Claim
20 words
The method of claim 1 or 2 wherein the gas channelling means comprises a sheet of flexible, gas permeable material.
Claim 8
Dependent Claim
15 words
The method of claim 6 wherein the flexible, gas permeable material is porous paper sheet.
Claim 9
Dependent Claim
15 words
The method of claim 1 or 2 wherein the gas channeling means is particulate material.
Claim 10
Dependent Claim
28 words
The method of claim 1 wherein bubble nucleation and growth is initiated by heating the exposed polymer article to above the glass transition temperature of the exposed polymer.
Claim 11
Dependent Claim
38 words
The method of claim 9 wherein bubble nucleation and growth is initiated by drawing the exposed polymer article through a heating means selected from the group consisting of hot liquid baths, hot gas or gases, and radiant heaters.
Claim 12
Dependent Claim
21 words
The method of claim 10 wherein the exposed polymer article is held under tension while being drawn through the heating means.
Claim 13
Dependent Claim
18 words
The method of claim 1 wherein bubble nucleation and growth is terminated by cooling the exposed polymer article.
Claim 14
Dependent Claim
28 words
The method of claim 1 or 2 wherein the polymer article is selected from the group consisting of polystyrene, polyvinyl chloride, polycarbonate, PMMA, ABS copolymers and polyethylene terephthalate.
Claim 15
Dependent Claim
23 words
The method of claim 1 or 2 wherein the non-reacting gas is selected from the group consisting of nitrogen, carbon dioxide and air.
Claim 16
Dependent Claim
21 words
The method of claim 1 or 2 wherein the polymer article is polyethylene terephthalate and the non-reactive gas is carbon dioxide.
Claim 17
Dependent Claim
18 words
The method of claim 15 wherein the gas channelling means is a sheet of flexible, gas permeable material.
Claim 18
Dependent Claim
14 words
The method of claim 16 wherein the gas permeable material is porous paper sheet.
Claim 19
Dependent Claim
27 words
The method of claim 15 wherein the interleaved article is exposed to carbon dioxide at a pressure in the range of about 50 to about 1400 psi.
Claim 20
Dependent Claim
25 words
The method of claim 15 wherein the interleaved article is exposed to carbon dioxide for a period of between about 3 and about 100 hours.
Claim 21
Dependent Claim
32 words
The method of claim 15 wherein bubble nucleation and growth is initiated by heating the exposed polymer article to a temperature in the range of about 80° C. to about 200° C.
Claim 22
Dependent Claim
18 words
The method of claim 15 wherein bubble nucleation and growth is quenched by cooling the exposed polymer article.
Claim 23
Dependent Claim
19 words
The method of claim 1 further comprising the step of cooling the polymer article after bubble nucleation and growth.
Claim 24
Dependent Claim
13 words
The method of claim 22 wherein the cooling is accomplished by natural convection.
Claim 25
Dependent Claim
13 words
The method of claim 23 wherein the cooling is accomplished by forced convection.
Claim 26
Dependent Claim
20 words
The method of claim 24 wherein the cooling is accomplished by drawing the polymer article through a means for cooling.
Claim 27
Dependent Claim
22 words
The method of claim 24 wherein the cooling of the polymer article is accomplished by drawing the polymer article through cold air.
Claim 28
Dependent Claim
22 words
The method of claim 24 wherein the cooling of the polymer article is accomplished by drawing the polymer article through cold water.
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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) | 2000-11-03 | 2001-05-05 | 2001-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-03 | 2005-05-05 | 2005-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-03 | 2009-05-05 | 2009-11-04 | $7700.00 | Window Closed / Lapsed |