US3821171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous,solid-phase polymerization of polyamide granules
Assignee: EIDP Inc
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Filing: 1972-06-09
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Granted: 1974-06-28
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Expires: 1992-06-09
Abstract
Abstract A solid-phase polymerization process for preparing polyamide granules of increased molecular weight by heating the granules while they are uncompacted and then subjecting polyamide molding granules to controlled heating above 200*C. in a solid-phase, plug-flow, gravity-conveyed polymerization zone.
Inventors
- 👤 D Beaton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:49
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/02; C08G69/04; C08G69/06; C08G69/26; C08G69/28; C08G69/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
67 words
The process of claim 1 in which the preselected temperature is between a 150 and 200*C. when the polycarbonamide is polyhexamethylene adipamide, b 135* and 185*C. when the polycarbonamide is polyhexamethylene sebacamide, c 170* and 205*C. when the polycarbonamide is polycaprolactam, d 140* and 185*C. when the polycarbonamide is polyhexamethylene dodecanediamide, and e 155* and 200*C. when the polycarbonamide is a copolymer of polyhexamethylene adipamide and epsilon-caprolactam.
Claim 2
Dependent Claim
31 words
The process of claim 2 in which the lower molecular weight polycarbonamide is heated to said preselected temperature prior to said granules passing into the plug flow, gravity conveyed reaction zone.
Claim 3
Dependent Claim
32 words
The process of claim 2 in which the lower molecular weight polycarbonamide is heated to said preselEcted temperature when it is the top layer in the plug flow, gravity conveyed reaction zone.
Claim 4
Dependent Claim
22 words
The process of claim 3 in which the lower molecular weight polycarbonamide is heated to said preselected temperature by heated inert gas.
Claim 5
Dependent Claim
12 words
The process of claim 5 in which the inert gas is nitrogen.
Claim 6
Dependent Claim
339 words
A plug flow process for the production of unagglomerated molding granules of high molecular weight saturated aliphatic polycarbonamide from saturated aliphatic polycarbonamide molding granules having a lower molecular weight which comprises: a. adding a layer of molding granules of said saturated aliphatic polycarbonamide having a lower molecular weight wherein the polycarbonamide is selected from the class consisting of polyhexamethylene adipamide, polyhexamethylene sebacamide, polycaprolactam, polyhexamethylene dodecanediamide, and a copolymer of polyhexamethylene adipamide and epsilon caprolactam into the top of a gravity-conveyed, partially filled reaction zone, the volume of the added layer of polycarbonamide molding granules being less than the volume necessary to fill said partially filled reaction zone, b. heating said added layer of polycarbonamide molding granules without agitation to a preselected temperature within the range of 135*C. to 205*C. while said layer exists as the top layer of the contents of the reaction zone by continuously passing a heated inert gas upwardly through said reaction zone, said heated inert gas having a temperature when it enters the bottom of the reaction zone higher than said preselected temperature but less than about 15*C. below the crystalline melting point of said polycarbonamide whereby agglomeration is prevented, c removing the portion of the contents of said reaction zone adjacent the bottom of the reaction zone unagglomerated from said reaction zone, which portion is at a temperature that is both in excess of 200*C. and said preselected temperature but not in excess of about 15*C. below the crystalline melting point of the polycarbonamide, d. adding a layer of said polycarbonamide molding granules having said lower molecular weight into the top of said reaction zone over the top of the previously added polycarbonamide layer, the volumetric amount of added polycarbonamide molding granules being such that the total solid volume of the contents of the reaction zone remains substantially constant, e. repeating steps (b), (c) and (d) above, f and recovering from the bottom of the reaction zone unagglomerated saturated aliphatic polycarbonamide molding granules having a higher molecular weight than those heated in step (a).
Claim 7
Dependent Claim
12 words
The process of claim 7 in which the polycarbonamide is polyhexamethylene adipamide.
Claim 8
Dependent Claim
23 words
The process of claim 8 in which the molding granules are heated in the reaction zone to a temperature between 225*C. and 240*C.
Claim 9
Dependent Claim
23 words
The process of claim 9 in which the residence time of the molding granules in the reaction zone is at least 2 hours.
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 |