US5158986A
Expired / Lapsed
US
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Microcellular thermoplastic foamed with supercritical fluid
Assignee: Massachusetts Institute of Technology
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Filing: 1991-04-05
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Granted: 1992-10-27
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Expires: 2011-04-05
Abstract
Abstract A supermicrocellular foamed material and a method for producing such material, the material to be foamed such as a polymerplastic material, having a supercritical fluid, such as carbon dioxide in its supercritical state, introduced into the material to form a foamed fluid/material system having a plurality of cells distributed substantially throughout the material. Cell densities lying in a range from about 10 9 to about 10 15 per cubic centimeter of the material can be achieved with the average cell sizes being at least less than 2.0 microns and preferably in a range from about 0.1 micron to about 1.0 micron.
Inventors
- 👤 Sung W. Cha
- 👤 Nam P. Suh
- 👤 Daniel F. Baldwin
- 👤 Chul B. Park
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:01
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/122; B; B29; B29C; B29C44/00; B29C44/34; B29C44/3442; B29C44/3446; B29C44/3469; B29C44/348; C08J2201/00; C08J2201/02; C08J2201/03; C08J2203/00; C08J2203/08; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/13
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
37 words
A foamed material comprising a non-thermosetting, polymerized plastic material to be foamed; a supercritical fluid introduced into said polymerized plastic material to form a supercritical fluid/material system having a plurality of cells distributed substantially throughout said material.
Claim 2
Dependent Claim
37 words
A foamed material comprising a non-thermosetting, polymerized plastic material to be foamed; a supercritical fluid introduced into said polymerized plastic material to form a supercritical fluid/material system having a plurality of cells distributed substantially throughout said material.
Claim 3
Dependent Claim
22 words
A foamed material according to claim 1 wherein said supercritical fluid is a carbon dioxide fluid which is in its supercritical state.
Claim 4
Dependent Claim
31 words
A foamed material according to claim 1 wherein said polymerized plastic material is selected from the group consisting of amorphous polymers, semi-crystalline polymers, liquid crystal polymers, thermosetting polymers, and elastomeric polymers.
Claim 5
Dependent Claim
48 words
A foamed material according to claim 1 wherein said supercritical fluid is introduced into said polymerized plastic material at a first selected pressure and at a first selected temperature whereby said cells are formed when said polymerized plastic material having said supercritical fluid introduced therein is thermodynamically destabilized.
Claim 6
Dependent Claim
92 words
A non-thermosetting polymer plastic foamed material having a plurality of closed cells substantially uniformly distributed therein, the cell density of said cells in said material lying in a range from about 10 9 to about 10 15 cells per cubic centimeter of said material, the average size of said cells being less than 2 microns, wherein the total volume of the cells formed in said foamed material comprise a fractional percentage of the total volume of said foamed material which lies within a range from about 20 to about 90 fraction percent.
Claim 7
Dependent Claim
92 words
A non-thermosetting polymer plastic foamed material having a plurality of closed cells substantially uniformly distributed therein, the cell density of said cells in said material lying in a range from about 10 9 to about 10 15 cells per cubic centimeter of said material, the average size of said cells being less than 2 microns, wherein the total volume of the cells formed in said foamed material comprise a fractional percentage of the total volume of said foamed material which lies within a range from about 20 to about 90 fraction percent.
Claim 8
Dependent Claim
45 words
A foamed material according to claim 5 wherein said density lies in a range from about 10 12 to about 10 15 cells per cubic centimeter of said material and the average size thereof is within a range from about 0.1 to about 1.0 micron.
Claim 9
Dependent Claim
19 words
A foamed material according to claims 5 or 6 wherein said fractional percentage is less than 50 fraction percent.
Claim 10
Independent Claim
85 words
A method of producing a foamed material comprising the steps of providing a non-thermosetting, polymerized plastic material to be foamed; introducing a supercritical fluid into said polymerized plastic material to be foamed at a first temperature and at a first pressure; externally changing the temperature and pressure from said first temperature and said first pressure to a different selected second temperature and a different selected second pressure to produce a supermicrocellular foamed material containing a plurality of voids or cells distributed substantially throughout said material.
Claim 11
Independent Claim
85 words
A method of producing a foamed material comprising the steps of providing a non-thermosetting, polymerized plastic material to be foamed; introducing a supercritical fluid into said polymerized plastic material to be foamed at a first temperature and at a first pressure; externally changing the temperature and pressure from said first temperature and said first pressure to a different selected second temperature and a different selected second pressure to produce a supermicrocellular foamed material containing a plurality of voids or cells distributed substantially throughout said material.
Claim 12
Dependent Claim
80 words
A method in accordance with claim 8 wherein said introducing step includes supplying a fluid at a temperature and pressure below the critical temperature and the critical pressure at which said fluid is in its supercritical fluid state; raising the temperature and pressure of said fluid to said first temperature and said first pressure above said critical temperature and said critical pressure, whereby said fluid in its supercritical fluid state is introduced into said polymerized plastic material to be foamed.
Claim 13
Dependent Claim
35 words
A method in accordance with claim 8 wherein the introduction of said supercritical fluid takes place over a time period sufficient to cause said polymerized plastic material to become effectively saturated with said supercritical fluid.
Claim 14
Dependent Claim
24 words
A foamed material in accordance with claim 5 wherein the average size of said closed cells is such that said foamed material is transparent.
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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) | 1995-10-27 | 1996-04-27 | 1996-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-27 | 2000-04-27 | 2000-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-27 | 2004-04-27 | 2004-10-27 | $7700.00 | Window Closed / Lapsed |