Patent US6636248B1 successfully refreshed from Google Patents.
US4226973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for upgrading prepolymer particles
Assignee: BP Corp North America Inc
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Filing: 1979-06-22
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Granted: 1980-10-07
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Expires: 1999-06-22
Abstract
Abstract A horizontal, agitated, twin-shaft, jacketed vessel with adjustable vanes performs the functions of drying, crystallization, and solid phase polymerization for upgrading prepolymer particles.
Inventors
- 👤 Russell V. Malo
- 👤 Gary A. Gustafson
- 👤 Ronald E. Bockrath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:37
CPC Classifications
B; B29; B29B; B29B13/00; C; C08; C08G; C08G63/00; C08G63/78; C08G63/785; C08G63/80
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
45 words
A process for upgrading polyester prepolymer particles comprising continuously conveying polyester prepolymer particles through a thermovane processor under an inert gas sweep at a temperature below the softening point of the polyester and sufficient to achieve crystallization and/or solid-state polymerization without sticking of the particles.
Claim 2
Dependent Claim
45 words
A process for upgrading polyester prepolymer particles comprising continuously conveying polyester prepolymer particles through a thermovane processor under an inert gas sweep at a temperature below the softening point of the polyester and sufficient to achieve crystallization and/or solid-state polymerization without sticking of the particles.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein the polyester comprises diol and diacid moieties wherein said diol comprises ethylene glycol and said diacid comprises terephthalic acid.
Claim 4
Dependent Claim
11 words
The process of claim 2 wherein the polyester is a homopolymer.
Claim 5
Dependent Claim
13 words
The process of claim 2 wherein the polyester is a poly(ethylene terephthalate) copolymer.
Claim 6
Dependent Claim
16 words
The process of claim 4 wherein the copolymer comprises moieties of isophthalic acid and trimellitic acid.
Claim 7
Dependent Claim
29 words
The process of claim 5 wherein the polyester particles are crystallized and further polymerized in a first thermovane processor and thereafter still further polymerized in a second thermovane processor.
Claim 8
Dependent Claim
69 words
A process for upgrading partially crystallized poly(ethylene terephthalate) copolyester particles having a degree of crystallization of at least about 5 percent, said process comprising continuously conveying the particles through two serially-connected thermovane processors, without sticking, under an inert gas sweep and at a temperature below 235° C. wherein the particles are dried, crystallized, and polymerized in the first thermovane processor and thereafter further polymerized in the second thermovane processor.
Claim 9
Dependent Claim
69 words
A process for upgrading partially crystallized poly(ethylene terephthalate) copolyester particles having a degree of crystallization of at least about 5 percent, said process comprising continuously conveying the particles through two serially-connected thermovane processors, without sticking, under an inert gas sweep and at a temperature below 235° C. wherein the particles are dried, crystallized, and polymerized in the first thermovane processor and thereafter further polymerized in the second thermovane processor.
Claim 10
Dependent Claim
30 words
The process of claim 7 wherein the inert gas is nitrogen and flows at a rate of from about 0.5 to about 20 kilograms of nitrogen per kilogram of particles.
Claim 11
Dependent Claim
23 words
The process of claim 8 wherein the nitrogen flow rate is from about 1 to about 2 kilograms nitrogen per kilogram of particles.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-07 | 1984-04-07 | 1984-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-07 | 1988-04-07 | 1988-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-07 | 1992-04-07 | 1992-10-07 | $7700.00 | Window Closed / Lapsed |