US4228076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of densifying open-celled polyurethane material
Assignee: IMAGINATIVETECHNOLOGY INTERNATIONAL Ltd A CORP OF IL
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Filing: 1979-05-31
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Granted: 1980-10-14
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Expires: 1999-05-31
Abstract
Abstract A method of densifying open-celled polyurethane foam is provided in which heated air at a temperature between about 425 DEG F. and 460 DEG F. is circulated through a mass of the foam so as to rapidly and uniformly raise the temperature of the mass to between about 365 DEG F. and 435 DEG F., the mass is then compressed to a desired thickness while its temperature is maintained between 365 DEG F. and 435 DEG F., and the mass is then immediately permitted to cool.
Inventors
- 👤 Winslow L. Pettingell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:14
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/56; B29C44/5627; B29C44/5636; B29K; B29K2075/00; B29K2105/00; B29K2105/04; B29K2105/045; Y; Y10; Y10S; Y10S264/00; Y10S264/66
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
146 words
A method of densifying a mass of fully cured open-celled polyurethane foam, said method comprising the consecutive steps of: passing heated gaseous material entirely through the mass, the temperature of said gaseous material being in the range of about 425° F. to 460° F. and the velocity of said gaseous material being insufficient to destroy the integrity of the cell walls of the mass, said gaseous material being inert with respect to the polyurethane, and the period of exposure of the mass to the gaseous material being insufficient to allow charring of the mass, yet sufficient to raise the entire mass substantially uniformly to a temperature between about 365° F. and 435° F.; compressing the mass while its temperature is between about 365° F. and 435° F. to reduce its thickness and thus increase its density to a desired degree; and permitting the mass to cool.
Claim 2
Independent Claim
146 words
A method of densifying a mass of fully cured open-celled polyurethane foam, said method comprising the consecutive steps of: passing heated gaseous material entirely through the mass, the temperature of said gaseous material being in the range of about 425° F. to 460° F. and the velocity of said gaseous material being insufficient to destroy the integrity of the cell walls of the mass, said gaseous material being inert with respect to the polyurethane, and the period of exposure of the mass to the gaseous material being insufficient to allow charring of the mass, yet sufficient to raise the entire mass substantially uniformly to a temperature between about 365° F. and 435° F.; compressing the mass while its temperature is between about 365° F. and 435° F. to reduce its thickness and thus increase its density to a desired degree; and permitting the mass to cool.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein the gaseous material is air.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein the gaseous material is circulated downwardly through the mass.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein the mass is maintained in the temperature range of 365° F. to 435° F. for a time not exceeding about one minute.
Claim 6
Dependent Claim
21 words
The method of claim 1 wherein the mass is moved into a zone at ambient temperature immediately after it is compressed.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein the mass is moved continuously endwise and is compressed between pinch rollers.
Claim 8
Dependent Claim
28 words
The method of claim 6 wherein the mass is maintained in the temperature range of 365° F. to 435° F. for a time not exceeding about one minute.
Claim 9
Dependent Claim
27 words
The method of claim 7 wherein the mass is permitted to cool by moving it endwise out of the pinch rollers into a zone at ambient temperature.
Claim 10
Dependent Claim
22 words
The method of claim 1 wherein the mass is moved in a discontinuous fashion and is compressed between two flat parallel surfaces.
Claim 11
Dependent Claim
18 words
The method of claim 9 wherein at least one of said flat parallel surfaces comprises a movable platen.
References Cited (Backward Citations)
US2933767A
Cited
US3050432A
Cited
US3061885A
Cited
US3060137A
Cited
US3112524A
Cited
US3325338A
Cited
US3400196A
Cited
US3475525A
Cited
US3443007A
Cited
US3506600A
Cited
US3577519A
Cited
US4073979A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |