Patent JPS6212937A successfully refreshed from Google Patents.
US4387213A
Expired / Lapsed
US
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Process for the condensation of linear polyalkylene terephthalates
Assignee: Huels AG
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Filing: 1980-12-22
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Granted: 1983-06-07
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Expires: 2000-12-22
Abstract
Abstract A process for condensing a linear polyalkylene terephthalate having a viscosity number of at least 60 cc/g in two stages, at an elevated temperature, in the solid phase, and in the presence of an alkanediol, comprises, in a first stage, treating the polyalkylene terephthalate in an inert gas stream at a reaction temperature 30°-80° C. below its melting point, with 0.2-3.5% by weight, based on the weight of the polyalkylene terephthalate, of an alkanediol whose boiling point under normal pressure is 20°-70° C. above the reaction temperature, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 0.3 to 2 times the gross reactor volume; and, in a second stage, condensing the polyalkylene terephthalate in an inert gas stream at a temperature 5°-25° C. below its melting point, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 2.5 to 10 times the gross reactor volume.
Inventors
- 👤 Gernot Horlbeck
- 👤 Horst Heuer
- 👤 Hanns-Jorg Bax
- 👤 Hans Jadamus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:48
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/80
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
204 words
A process for recondensing a linear polyalkylene terephthalate in two stages, at an elevated temperature, in the solid phase, and in the presence of an alkanediol, and the polyalkylene terephthalate having a viscosity number of at least 60 cc/g as measured in a solution of 0.23 g of polyalkylene terephthalate in 100 ml of phenol/1,1,2,2-tetrachloroethane (weight ratio 60:40) at 25° C., comprising, in a first stage, treating the polyalkylene terephthalate in an inert gas stream at a reaction temperature 30°-80° C. below its melting point, with 0.2-3.5% by weight, based on the weight of the polyalkylene terephthalate, of an alkanediol whose boiling point under normal pressure is 20-70° C. above the reaction temperature, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 0.3 to 2 times the gross reactor volume, and wherein the first stage is conducted until the polyalkylene terephthalate has achieved essentially its minimum carboxy end group concentration; and, in a second stage, condensing the polyalkylene terephthalate in an inert gas stream at a temperature 5°-25° C. below its melting point, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 2.5 to 10 times the gross reactor volume.
Claim 2
Dependent Claim
204 words
A process for recondensing a linear polyalkylene terephthalate in two stages, at an elevated temperature, in the solid phase, and in the presence of an alkanediol, and the polyalkylene terephthalate having a viscosity number of at least 60 cc/g as measured in a solution of 0.23 g of polyalkylene terephthalate in 100 ml of phenol/1,1,2,2-tetrachloroethane (weight ratio 60:40) at 25° C., comprising, in a first stage, treating the polyalkylene terephthalate in an inert gas stream at a reaction temperature 30°-80° C. below its melting point, with 0.2-3.5% by weight, based on the weight of the polyalkylene terephthalate, of an alkanediol whose boiling point under normal pressure is 20-70° C. above the reaction temperature, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 0.3 to 2 times the gross reactor volume, and wherein the first stage is conducted until the polyalkylene terephthalate has achieved essentially its minimum carboxy end group concentration; and, in a second stage, condensing the polyalkylene terephthalate in an inert gas stream at a temperature 5°-25° C. below its melting point, wherein the amount of inert gas passed through per hour, measured under standard conditions, corresponds to 2.5 to 10 times the gross reactor volume.
Claim 3
Dependent Claim
39 words
A process of claim 1 wherein the first and second stages are carried out in the same reactor and the second stage is effected by continuing the first stage with said increased inert gas flow and said increased temperature.
Claim 4
Dependent Claim
24 words
A process of claim 2, wherein the polyalkylene terephthalate is treated in the fist stage at a temperature 35°-60° C. below its melting point.
Claim 5
Dependent Claim
30 words
A process of claim 2, wherein the polyalkylene terephthalate is treated in the first stage with 0.3-1% by weight, based on the weight of the polyalkylene terephthalate, of the alkanediol.
Claim 6
Dependent Claim
31 words
A process of claim 2, wherein the polyalkylene terephthalate is treated in the first stage with an alkanediol whose boiling point under normal pressure is 30°-60° C. above the reaction temperature.
Claim 7
Dependent Claim
33 words
A process of claim 2, wherein in the first stage, the amount of inert gas passed through per hour, measured under normal conditions, corresponds to 0.5 to 1.5 times the gross reactor volume.
Claim 8
Dependent Claim
24 words
A process of claim 2, wherein the polyalkylene terephthalate, in the second stage, is condensed at a temperature 10°-20° C. below its melting point.
Claim 9
Dependent Claim
33 words
A process of claim 2, wherein in the second stage, the amount of inert gas passed through per hour, measured under normal conditions, corresponds to 3 to 7 times the gross reactor volume.
Claim 10
Dependent Claim
11 words
A process of claim 2, wherein the inert gas is nitrogen.
Claim 11
Dependent Claim
22 words
A process of claim 2 wherein the alkanediol used in the first stage corresponds to the alkylene portion of the polyalkylene terephthalate.
Claim 12
Dependent Claim
17 words
A process of claim 2 wherein the viscosity number of the starting polyalkylene terephthalate is 60-100 cc/g.
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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) | 1986-06-06 | 1986-12-06 | 1987-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-06 | 1990-12-06 | 1991-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-06 | 1994-12-06 | 1995-06-07 | $7700.00 | Window Closed / Lapsed |