US5543495A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for increasing the molecular weight of polyamides and other condensation polymers
Assignee: Invista North America LLC
•
Filing: 1994-03-08
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Granted: 1996-08-06
•
Expires: 2014-03-08
Abstract
Abstract This invention concerns a process for increasing the molecular weight and viscosity of polyamides and other condensation polymers, by first injecting an inert gas into the polymer melt at elevated pressure, then stripping the volatiles from the polymer through the application of reduced pressure, followed by holding the polymer at elevated temperatures long enough for the reaction to occur. Activators may be added to the polymer. Port areas used in the stripping zone, may be kept hot for continuous operation.
Inventors
- 👤 Colin Anolick
- 👤 Gregory D. Cramer
- 👤 Ramdas Dujari
- 👤 Win-Chung Lee
- 👤 Sundar M. Rao
- 👤 Robert C. Wheland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:43
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/82; C08G63/87; C08G69/00; C08G69/02; C08G69/26; C08G69/28; C08G63/83
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
134 words
A process for increasing the molecular weight of polyamide or polyester polymers, said process performed in a pressurized vessel where the polymer is in melt form, which process comprises the successive steps of: (a) injecting and mixing steam or an inert gas, as a stripping agent, into the polymer melt, under elevated pressure, so as to result in a polymer condensation reaction, with the concurrent production of evaporated gases; (b) reducing the pressure of the polymer melt so that the partial pressure of the product of the polymer condensation reaction is reduced and removing the resulting evaporated gases through a vent port; and (c) after removing the evaporated gases, holding the polymer melt at reaction temperature for a sufficient time to allow the reaction to proceed to a desired increased number average molecular weight.
Claim 2
Dependent Claim
134 words
A process for increasing the molecular weight of polyamide or polyester polymers, said process performed in a pressurized vessel where the polymer is in melt form, which process comprises the successive steps of: (a) injecting and mixing steam or an inert gas, as a stripping agent, into the polymer melt, under elevated pressure, so as to result in a polymer condensation reaction, with the concurrent production of evaporated gases; (b) reducing the pressure of the polymer melt so that the partial pressure of the product of the polymer condensation reaction is reduced and removing the resulting evaporated gases through a vent port; and (c) after removing the evaporated gases, holding the polymer melt at reaction temperature for a sufficient time to allow the reaction to proceed to a desired increased number average molecular weight.
Claim 3
Dependent Claim
23 words
Process of claim 1 where an activator is added to the polymer melt prior to the holding period described in claim 1 (c).
Claim 4
Dependent Claim
10 words
The process of claim 1 wherein the polyester is polyethyleneterephthalate.
Claim 5
Dependent Claim
10 words
The process of claim 1 wherein the polyester is polyethyleneterephthalate.
Claim 6
Dependent Claim
22 words
The process of claim 1 wherein the polyamide, is selected from the group consisting of nylon 6, nylon 66, and nylon 612.
Claim 7
Dependent Claim
22 words
The process of claim 1 wherein the polyamide, is selected from the group consisting of nylon 6, nylon 66, and nylon 612.
Claim 8
Dependent Claim
33 words
The process of claim 2 wherein the polymer is polyamide and the activator is selected from the group consisting of sodium hypophosphite (SHP), manganese hypophosphite (MnHP), phenylphosphinic acid (PPA) and 2-(2'-pyridyl)ethylphosphonic acid (PEPA).
Claim 9
Dependent Claim
13 words
The process of claim 7 wherein the activator is 2-(2'-pyridyl) ethylphosphonic acid (PEPA).
Claim 10
Dependent Claim
22 words
The process of claim 1 wherein the stripping agent is selected from the group consisting of steam, nitrogen, carbon dioxide and argon.
Claim 11
Dependent Claim
22 words
The process of claim 2 wherein the stripping agent is selected from the group consisting of steam, nitrogen, carbon dioxide and argon.
Claim 12
Dependent Claim
19 words
The process of claim 9 wherein 0.1% to 4.0%, based on polymer weight, of the stripping agent is used.
Claim 13
Dependent Claim
19 words
The process of claim 10 wherein 0.1% to 4.0% based on polymer weight, of the stripping agent is used.
Claim 14
Dependent Claim
19 words
The process of claim 1 wherein the the elevated pressure of step (a) is 2 psig to 300 psig.
Claim 15
Dependent Claim
19 words
The process of claim 2 wherein the the elevated pressure of step (a) is 2 psig to 300 psig.
Claim 16
Dependent Claim
18 words
The process of claim 13 wherein the elevated pressure of step (a) is 5 psig to 150 psig.
Claim 17
Dependent Claim
18 words
The process of claim 14 wherein the elevated pressure of step (a) is 5 psig to 150 psig.
Claim 18
Dependent Claim
19 words
The process of claim 1 wherein step (a) is carried out in a twin screw or single screw extruder.
Claim 19
Dependent Claim
19 words
The process of claim 2 wherein step (a) is carried out in a twin screw or single screw extruder.
Claim 20
Dependent Claim
18 words
The process of claim 1 wherein the reduced pressure employed in step (b) is less than 25 psia.
Claim 21
Dependent Claim
18 words
The process of claim 2 wherein the reduced pressure employed in step (b) is less than 25 psia.
Claim 22
Dependent Claim
17 words
The process of claim 19 wherein the reduced pressure in step (b) is less than 20 psia.
Claim 23
Dependent Claim
17 words
The process of claim 20 wherein the reduced pressure in step (b) is less than 20 psia.
Claim 24
Dependent Claim
23 words
The process of claim 1 wherein the stripping agent is steam and the reduced pressure in step (b) is less than 10 psia.
Claim 25
Dependent Claim
23 words
The process of claim 2 wherein the stripping agent is steam and the reduced pressure in step (b) is less than 10 psia.
Claim 26
Dependent Claim
17 words
The process of claim 23 wherein the reduced pressure in step (b) is less than 5 psia.
Claim 27
Dependent Claim
26 words
The process of claim 1 conducted at a temperature that is about 2° C. to about 75° C. above the melting temperature of the polymer used.
Claim 28
Dependent Claim
26 words
The process of claim 2 conducted at a temperature that is about 2° C. to about 75° C. above the melting temperature of the polymer used.
Claim 29
Dependent Claim
23 words
The process of claim 27 wherein the polymer is nylon 66 and the process is conducted at a temperature of about 290° C.
Claim 30
Dependent Claim
23 words
The process of claim 28 wherein the polymer is nylon 66 and the process is conducted at a temperature of about 290° C.
Claim 31
Dependent Claim
18 words
The process of claim 6 where the activator is added in the form of a solution in water.
Claim 32
Dependent Claim
20 words
The process of claim 6 where the activator is added as a dispersion in nylon or a low viscosity polyamide.
Claim 33
Dependent Claim
33 words
The process of claim 1 where the walls of the low pressure zone are heated to a temperature of 5° C. to 20° C. above the temperature of the polymer in the process.
Claim 34
Dependent Claim
33 words
The process of claim 2, where the walls of the low pressure zone are heated to a temperature of 5° C. to 20° C. above the temperature of the polymer in the process.
Claim 35
Dependent Claim
16 words
The process of claim 1 wherein the evaporated gases are removed through a heated vent port.
Claim 36
Dependent Claim
16 words
The process of claim 2 wherein the evaporated gases are removed through a heated vent port.
Claim 37
Dependent Claim
40 words
The process of claim 2 wherein the activator is added to the polymer melt after the removal of evaporated gases in step (c) and holding the melt at reaction temperature until the polymer reaches a desired number average molecular weight.
Claim 38
Dependent Claim
167 words
A process for increasing the molecular weight of a polyamide or polyester condensation polymer melt, after said polymer has been subjected to a drying process to remove moisture, said process performed in a pressurized vessel where the polymer is in melt form, which process comprises the steps of: (a) injecting and mixing steam or an inert gas, as a stripping agent, into the polymer melt, under elevated pressure, so as to result in a polymer condensation reaction, with the concurrent production of evaporated gases; (b) reducing the pressure of the polymer melt so that the partial pressure of the product of the polymer condensation reaction is reduced and removing the resulting evaporated gases through a vent port; and (c) after removing the evaporated gases, holding the polymer melt at reaction temperature for a sufficient time to allow the reaction to proceed to a desired increased number average molecular weight; wherein an activator is added to the polymer melt prior to the holding period described in part (c).
Claim 39
Dependent Claim
167 words
A process for increasing the molecular weight of a polyamide or polyester condensation polymer melt, after said polymer has been subjected to a drying process to remove moisture, said process performed in a pressurized vessel where the polymer is in melt form, which process comprises the steps of: (a) injecting and mixing steam or an inert gas, as a stripping agent, into the polymer melt, under elevated pressure, so as to result in a polymer condensation reaction, with the concurrent production of evaporated gases; (b) reducing the pressure of the polymer melt so that the partial pressure of the product of the polymer condensation reaction is reduced and removing the resulting evaporated gases through a vent port; and (c) after removing the evaporated gases, holding the polymer melt at reaction temperature for a sufficient time to allow the reaction to proceed to a desired increased number average molecular weight; wherein an activator is added to the polymer melt prior to the holding period described in part (c).
Claim 40
Dependent Claim
29 words
The process of claim 37 wherein the activator is selected from the group consisting of sodium hypophosphite (SHP), manganese hypophosphite (MnHP), phenylphosphinic acid (PPA) and 2-(2'-pyridyl) ethylphosphonic acid (PEPA).
Claim 41
Dependent Claim
26 words
The process of claim 2 wherein the activator is added at a concentration of about 0.1 gram to 10 grams per million grams of polymer product.
Claim 42
Dependent Claim
29 words
The process of claim 37 wherein the activator is added to said polymer melt while the polymer is subjected to a temperature of about 280° C. to 340° C.
Claim 43
Dependent Claim
130 words
A process for increasing the molecular weight of polyethyleneterephtalate, said process performed in a pressurized vessel where the polymer is in melt form, which process comprises the steps of: (a) injecting and mixing steam or an inert gas, as a stripping agent, into the polymer melt, under elevated pressure, so as to result in a polymer condensation reaction, with the concurrent production of evaporated gases; (b) reducing the pressure of the polymer melt so that the partial pressure of the product of the polymer condensation reaction is reduced and removing the resulting evaporated gases through a vent port; and (c) after removing the evaporated gases, holding the polymer melt at reaction temperature for a sufficient time to allow the reaction to proceed to a desired increased number average molecular weight.
Claim 44
Dependent Claim
130 words
A process for increasing the molecular weight of polyethyleneterephtalate, said process performed in a pressurized vessel where the polymer is in melt form, which process comprises the steps of: (a) injecting and mixing steam or an inert gas, as a stripping agent, into the polymer melt, under elevated pressure, so as to result in a polymer condensation reaction, with the concurrent production of evaporated gases; (b) reducing the pressure of the polymer melt so that the partial pressure of the product of the polymer condensation reaction is reduced and removing the resulting evaporated gases through a vent port; and (c) after removing the evaporated gases, holding the polymer melt at reaction temperature for a sufficient time to allow the reaction to proceed to a desired increased number average molecular weight.
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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) | 1999-08-06 | 2000-02-05 | 2000-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-06 | 2004-02-05 | 2004-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-06 | 2008-02-05 | 2008-08-06 | $7700.00 | Window Closed / Lapsed |