US4374975A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of high molecular weight polyester
Assignee: Shell USA Inc
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Filing: 1982-02-02
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Granted: 1983-02-22
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Expires: 2002-02-02
Abstract
Abstract A process for the continuous production of high molecular weight polyethylene terephthalate wherein the crystallized prepolymer having an intrinsic viscosity of at least 0.3 is dried, preheated and polymerized in a single moving bed reaction zone. The method is characterized by an inert gas atmosphere and a reaction zone with a temperature gradiant ranging from about 170 DEG C. at the uppermost portion and a higher temperature of about 225 DEG C. at the lowermost portion.
Inventors
- 👤 Ben Duh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:52
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/80
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
95 words
In a process for the continuous solid state polymerization of crystalline linear polyester prepolymer wherein the crystalline polyester is further polymerized, the improvement comprising introducing a crystalline linear polyester prepolymer having an appreciable moisture content to a single moving bed reaction zone, countercurrently contacting said polyester within the reaction zone with a heated inert gas wherein the temperature of the crystalline polyester is increased from about 170° C. to its polymerization temperature of about 200° C. to 225° C. whereby said polyester is further polymerized in its crystalline form without severe degradation of the polyester.
Claim 2
Dependent Claim
95 words
In a process for the continuous solid state polymerization of crystalline linear polyester prepolymer wherein the crystalline polyester is further polymerized, the improvement comprising introducing a crystalline linear polyester prepolymer having an appreciable moisture content to a single moving bed reaction zone, countercurrently contacting said polyester within the reaction zone with a heated inert gas wherein the temperature of the crystalline polyester is increased from about 170° C. to its polymerization temperature of about 200° C. to 225° C. whereby said polyester is further polymerized in its crystalline form without severe degradation of the polyester.
Claim 3
Independent Claim
72 words
A method for the solid state polymerization of polyester resins comprising heating a crystallized prepolymer into a single moving bed reaction zone for a time sufficient to dry and solid state polymerize the polyester to a desirable I.V. wihtout severe degradation due to a high moisture content of the polyester, wherein there is a temperature gradiant of from 170° C. at the uppermost section to about 225° C. at the lowermost section.
Claim 4
Independent Claim
72 words
A method for the solid state polymerization of polyester resins comprising heating a crystallized prepolymer into a single moving bed reaction zone for a time sufficient to dry and solid state polymerize the polyester to a desirable I.V. wihtout severe degradation due to a high moisture content of the polyester, wherein there is a temperature gradiant of from 170° C. at the uppermost section to about 225° C. at the lowermost section.
Claim 5
Independent Claim
87 words
A method for the solid state polymerization of polyethylene terephthalate comprising feeding a crystalline polyethylene terephthalate characterized by an I.V. of at least 0.3 and an initial moisture content of up to 0.35 percent by weight, into a single moving bed reaction zone wherein said zone there is a counter-current flow of hot inert gas and there is a temperature gradiant of from about 170° C. at the upper most section of said zone and from about 225° C. at the lower most section of said zone.
Claim 6
Independent Claim
87 words
A method for the solid state polymerization of polyethylene terephthalate comprising feeding a crystalline polyethylene terephthalate characterized by an I.V. of at least 0.3 and an initial moisture content of up to 0.35 percent by weight, into a single moving bed reaction zone wherein said zone there is a counter-current flow of hot inert gas and there is a temperature gradiant of from about 170° C. at the upper most section of said zone and from about 225° C. at the lower most section of said zone.
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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) | 1986-02-21 | 1986-08-23 | 1987-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-21 | 1990-08-23 | 1991-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-21 | 1994-08-23 | 1995-02-22 | $7700.00 | Window Closed / Lapsed |