US4442260A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of salt solution useful for making nylon
Assignee: EIDP Inc
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Filing: 1983-03-14
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Granted: 1984-04-10
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Expires: 2003-03-14
Abstract
Abstract A process is described for making highly concentrated solutions of nylon salt in which the diamine is added in two portions, one before and one after a step in which water is evaporated from a solution of maximum solubility.
Inventors
- 👤 Howland A. Larsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:05
CPC Classifications
C; C07; C07C; C07C209/00; C07C209/68; C07C51/00; C07C51/41; C07C51/412; C08; C08G; C08G69/00; C08G69/02; C08G69/26; C08G69/28
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
86 words
A process for making 66-nylon salt solution which comprises, in sequence (a) preparing a water solution in which the solute phase contains 73.5-77.5% adipic acid and 22.5-26.5% hexamethylene diamine, by weight, at a temperature of 55°-60° C. in which the total solute concentration is 60-69% and the water concentration is 31-40%, and (b) concentrating the solution by evaporating water until the solute comprises between 89 and 96%, by weight, and (c) adding hexamethylene diamine until the hexamethylene diamine and adipic acid are in about stoichiometric proportions.
Claim 2
Dependent Claim
86 words
A process for making 66-nylon salt solution which comprises, in sequence (a) preparing a water solution in which the solute phase contains 73.5-77.5% adipic acid and 22.5-26.5% hexamethylene diamine, by weight, at a temperature of 55°-60° C. in which the total solute concentration is 60-69% and the water concentration is 31-40%, and (b) concentrating the solution by evaporating water until the solute comprises between 89 and 96%, by weight, and (c) adding hexamethylene diamine until the hexamethylene diamine and adipic acid are in about stoichiometric proportions.
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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) | 1987-04-10 | 1987-10-10 | 1988-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-10 | 1991-10-10 | 1992-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-10 | 1995-10-10 | 1996-04-10 | $7700.00 | Window Closed / Lapsed |