US4642211A
Expired / Lapsed
US
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Preparation of dry polycaprolactam granules
Assignee: BASF SE
•
Filing: 1984-10-19
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Granted: 1987-02-10
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Expires: 2004-10-19
Abstract
Abstract Dry polycaprolactam granules containing from 8 to 13% by weight of caprolactam and its oligomers are prepared by a method in which a caprolactam melt is extruded, the extrudates are cooled to 100°-150° C., left at this temperature until the polycaprolactam has substantially crystallized, and then immediately granulated, and the granules are left in a stream of inert gas, in the absence of molecular oxygen, for from 1 to 4 hours at from 100° to 150° C., and are then cooled.
Inventors
- 👤 Peter Elbs
- 👤 Wolfgang-Dieter Jeserich
- 👤 Rudolf Wehr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:35
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08J2377/00; C08J2377/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
92 words
A process for the preparation of dry polycaprolactam granules containing from 8 to 13% by weight of caprolactam and its oligomers which comprises: extruding a polycaprolactam melt containing the stated amount of caprolactam and its oligomers, cooling the extrudates to 100°-150° C., maintaining the extrudates at this temperature until the polycaprolactam has substantially crystallized, and then immediately granulating the extrudates, and maintaining the granules in a stream of inert gas, in the absence of molecular oxygen, for from 1 to 4 hours at from 100° to 150° C., and cooling the granules.
Claim 2
Dependent Claim
92 words
A process for the preparation of dry polycaprolactam granules containing from 8 to 13% by weight of caprolactam and its oligomers which comprises: extruding a polycaprolactam melt containing the stated amount of caprolactam and its oligomers, cooling the extrudates to 100°-150° C., maintaining the extrudates at this temperature until the polycaprolactam has substantially crystallized, and then immediately granulating the extrudates, and maintaining the granules in a stream of inert gas, in the absence of molecular oxygen, for from 1 to 4 hours at from 100° to 150° C., and cooling the granules.
Claim 3
Dependent Claim
40 words
The process of claim 1, wherein the extrudates are cooled to 100°-150° C. by being brought into contact with water for a short time, and are then left in the air at this temperature until the polycaprolactam has substantially crystallized.
Claim 4
Dependent Claim
42 words
The process of claim 1, wherein the extrudates are brought into contact with water for from 0.5 to 5 seconds, after which the polycaprolactam is substantially crystallized in the course of from 2 to 20 seconds in air at from 100°-150° C.
Claim 5
Dependent Claim
18 words
The process of claim 1, wherein the inert gas used contains less than 10 ppm of molecular oxygen.
Claim 6
Dependent Claim
22 words
The process of claim 1, wherein the granules are left in a stream of inert gas at from 125° to 150° C.
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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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |