Patent US3816369A successfully refreshed from Google Patents.
US3816369A
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Process for the preparation of polyamides with alkali metal dihydrogen orthophosphate as catalyst
Assignee: Imperial Chemical Industries Ltd
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Filing: 1972-10-19
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Granted: 1974-06-11
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Expires: 1992-10-19
Abstract
Abstract Production of fiber forming polyamides from aromatic diamines and dicarboxylic acids by a melt poly condensation in the presence of at least one alkali metal dihydrogen orthophosphate as catalyst.
Inventors
- 👤 I Thomas
- 👤 J Traynor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:54
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/42; C08G69/02; C08G69/26; C08G69/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
26 words
A process as claimed in claim 1 in which the diaminodiphenyl sulphone or amide-forming derivative thereof forms substantially all of the diamine component in the mixture.
Claim 2
Dependent Claim
77 words
A process as claimed in claim 1 in which the diamine or amide-forming derivative thereof comprises up to 20 mole percent of at least one aliphatic diamine having the structure H2N CH2 (CR1R2)m CH2NH2 1 or amide forming derivative thereof, where R1 and R2, which may be the same or different, are hydrogen atoms or alkyl groups having not more than four carbon atoms, and m is 0 or an integer in the range 1 to 10.
Claim 3
Dependent Claim
15 words
A process as claimed in claim 1 in which the diaminodiphenyl sulphone is 4,4''-diaminodiphenyl sulphone.
Claim 4
Dependent Claim
36 words
A process as claimed in claim 3 in which the diamine or amide-forming derivative thereof comprises from 5 to 10 mole percent of at least one aliphatic diamine having the structure I, or amide-forming derivative thereof.
Claim 5
Dependent Claim
38 words
A process as claimed in any claim 1 in which the dicarboxylic acId, or amide-forming derivative thereof, is at least one Alpha , omega -polymethylene dicarboxylic acid having from six to 16 carbon atoms, or amide-forming derivative thereof.
Claim 6
Dependent Claim
39 words
A process as claimed in claim 6 in which up to 36 mole percent of the Alpha , omega -polymethylene dicarboxylic acid, or amide-forming derivative thereof, is replaced by at least one carbocyclic dicarboxylic acid or amide-forming derivative thereof.
Claim 7
Dependent Claim
26 words
A process as claimed in claim 6 in which the Alpha , omega -dicarboxylic acid or amide-forming derivative thereof is azeleic acid or amide-forming derivative thereof.
Claim 8
Dependent Claim
26 words
A process as claimed in claim 1 in which the alkali metal dihydrogen orthophosphate is sodium dihydrogen orthophosphate or potassium dihydrogen orthophosphate, or a mixture thereof.
Claim 9
Dependent Claim
47 words
A process as claimed in claim 1 in which the alkali metal dihydrogen orthophosphate, or mixture thereof, is present in a proportion of 0.0001 to 1 part by weight for every 100 parts by weight of the mixture of diamine and dicarboxylic acid or amide-forming derivatives thereof.
Claim 10
Dependent Claim
22 words
A process as claimed in claim 1 in which the mixture is heated at a temperature in the range 220* to 300*C.
Claim 11
Dependent Claim
64 words
A process as claimed in claim 1 in which the heating of the mixture is effected in two stages, in a first stage at a temperature in the range 160*C to 240*C, and in a second stage at a higher temperature in the range 220*C to 290*C and under a vacuum equivalent to an absolute pressure of 1.0 mm of mercury absolute or less.
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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |