US3989677A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of polyamides
Assignee: Bayer AG
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Filing: 1974-11-15
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Granted: 1976-11-02
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Expires: 1994-11-15
Abstract
Abstract An improved process for the production of polyamides of low extract content by the activated anionic polymerisation of at least one lactam containing at least 5 ring members at temperatures above the melting point of the polyamide in a continuously working polymerisation apparatus, optionally followed directly by shaping, the improvement comprises treating the polyamide melt obtained by polymerising said lactam in said polymerisation apparatus with water or steam and subsequently freeing it from volatile constituents by evaporation before the polyamide melt is discharged into the open.
Inventors
- 👤 Bert Brassat
- 👤 Rolf Brockmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:20
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/46; C08G69/02; C08G69/08; C08G69/14; C08G69/16; C08G69/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
96 words
In a process for the production of polyamides of low extract content by activated anionic polymerisation of at least one lactam containing at least 5 ring members at a temperature above the melting point of the polyamide in a continuously working polymerisation apparatus comprising an extruder, the improvement comprising treating the polyamide melt obtained by polymerising said lactam in said extruder with water or steam for an average time of from about 0.5 to about 5 minutes before the polyamide melt is discharged into the open; and subsequently freeing the melt from volatile constituents by evaporation.
Claim 2
Dependent Claim
96 words
In a process for the production of polyamides of low extract content by activated anionic polymerisation of at least one lactam containing at least 5 ring members at a temperature above the melting point of the polyamide in a continuously working polymerisation apparatus comprising an extruder, the improvement comprising treating the polyamide melt obtained by polymerising said lactam in said extruder with water or steam for an average time of from about 0.5 to about 5 minutes before the polyamide melt is discharged into the open; and subsequently freeing the melt from volatile constituents by evaporation.
Claim 3
Dependent Claim
24 words
A process as claimed in claim 1, wherein the moldable polyamide melt is treated with water or steam for from 0.5 to 5 minutes.
Claim 4
Dependent Claim
17 words
A process as claimed in claim 2, wherein the treatment time is from 1 to 2 minutes.
Claim 5
Dependent Claim
26 words
A process as claimed in claim 1, wherein the lactam is caprolactam, lauric lactam, α-pyrrolidone, oenanthic lactam, capryllactam, or the corresponding C-substituted lactam, or mixtures thereof.
Claim 6
Dependent Claim
21 words
A process as claimed in claim 1, wherein said polymerisation apparatus is a ram or screw extruder or a tube reactor.
Claim 7
Dependent Claim
26 words
A process as claimed in claim 1, wherein a 5 to 20 fold excess of water or steam is used, based on the quantity of catalyst.
Claim 8
Dependent Claim
25 words
A process as claimed in claim 1, wherein the volatile constituents are evaporated off by the action of a vacuum or of an entraining gas.
Claim 9
Dependent Claim
18 words
A process as claimed in claim 7, wherein a vacuum of from 10 to 100 Torr is applied.
Claim 10
Dependent Claim
13 words
A process as claimed in claim 7, wherein the entraining gas is nitrogen.
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) | 1979-11-02 | 1980-05-03 | 1980-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-02 | 1984-05-03 | 1984-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-02 | 1988-05-03 | 1988-11-02 | $7700.00 | Window Closed / Lapsed |