US3821349A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Internal cooling of polyethylene terephthalate tubing
Assignee: Phillips Petroleum Co
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Filing: 1972-06-15
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Granted: 1974-06-28
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Expires: 1992-06-15
Abstract
Abstract Relatively heavy wall, clear polyethylene terephthalate tubing is prepared by extruding a tubular melt into contact with an external sizing and cooling surface while simultaneously cooling the inner surfaces by means of a mandrel within the tubing spaced apart from the inner walls thereof by a narrow annular gap. Upon exiting from the sizing sleeve, the tubing is passed through a water bath. The cooled tubing can be severed into open ended parison preforms and such preforms reheated and blow molded.
Inventors
- 👤 L Mozer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:31
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/90; B29C48/908; B29C48/03; B29C48/09; B29C48/901; B29C48/903; B29C48/91; B29C48/911; B29C48/9115; B29C48/919; B29C48/001; B29C48/0018; B29C48/0022; B29C48/10; B29C48/885; B29C48/905; B29C48/912
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
144 words
A method of forming clear thick walled polyethylene terephthalate tubing comprising forming a molten tubular extrudate of said polyethylene terephthalate at a melt temperature of from 500* to 590* F and solidifying said thusformed extrudate to form tubing by cooling said extrudate from the outside by passing it into direct contact with an external sizing sleeve having fluid at 20* to 60* F circulated there through while simultaneously cooling said extrudate from the inside by passing it axially over an internal cooling mandrel having fluid at 20* to 60* F circulated there through, which cooling mandrel is concentric with said extrudate, the external surface of said cooling mandrel being separated from an inner surface of said extrudate by a narrow annular gap having a finite dimension of no more than 25 mils, said cooled tubing having a wall thickness of greater than 90 mils.
Claim 2
Independent Claim
144 words
A method of forming clear thick walled polyethylene terephthalate tubing comprising forming a molten tubular extrudate of said polyethylene terephthalate at a melt temperature of from 500* to 590* F and solidifying said thusformed extrudate to form tubing by cooling said extrudate from the outside by passing it into direct contact with an external sizing sleeve having fluid at 20* to 60* F circulated there through while simultaneously cooling said extrudate from the inside by passing it axially over an internal cooling mandrel having fluid at 20* to 60* F circulated there through, which cooling mandrel is concentric with said extrudate, the external surface of said cooling mandrel being separated from an inner surface of said extrudate by a narrow annular gap having a finite dimension of no more than 25 mils, said cooled tubing having a wall thickness of greater than 90 mils.
Claim 3
Dependent Claim
20 words
A method according to claim 1 wherein said polymer is extruded at a melt temperature of 500* to 580* F.
Claim 4
Dependent Claim
21 words
A method according to claim 1 wherein said tubing on exiting from said sizing sleeve is passed through a water bath.
Claim 5
Dependent Claim
50 words
A method according to claim 3 wherein said external sizing sleeve is cooled with water at a temperature of 33* to 60* F, said mandrel is cooled with water at a temperature of 33* to 60* F, and said water bath is at a temperature of 33* to 60* F.
Claim 6
Dependent Claim
19 words
A method according to claim 3 wherein said melt temperature is within the range of 510* to 570* F.
Claim 7
Dependent Claim
19 words
A method according to claim 3 wherein said annular gap is within the range of 10 to 25 mils.
Claim 8
Dependent Claim
21 words
A method according to claim 3 wherein said tubing has a wall thickness within the range of 115 to 140 mils.
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) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |