Patent US3717696A successfully refreshed from Google Patents.
US3717696A
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Process for the preparation of polyamide-imide filaments
Assignee: Rhodiaceta SA
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Filing: 1971-02-09
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Granted: 1973-02-20
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Expires: 1991-02-09
Abstract
Abstract This invention provides a process for producing polyamide-imide filaments which are heat-stable and have high tensile strength by solvent spinning under specified conditions. In a preferred embodiment the polyamide-imide polymers in solution are extruded into filaments and fibers through a spinneret maintained at a temperature between 60* C. and 180* C. heated at a temperature higher than 160* C. up to about 240* C. at a constant length for 2 to 6 hours, and subsequently drawn at a drawing ratio of at least 3:1 at a temperature generally in the range of about 220* C. up to about 420* C.
Inventors
- 👤 Vincent Rochina
- 👤 Pierre Allard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:44
CPC Classifications
A; A61; A61H; A61H33/00; A61H33/06; A61H33/10; D; D01; D01F; D01F6/00; D01F6/58; D01F6/74
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
112 words
Process for producing heat stable filaments and fibers which comprises extruding through a spinneret maintained at a temperature between 60* and 180* C in an evaporatory atmosphere maintained at a temperature near or above the boiling point of the solvent, a solution in an inert organic polar solvent selected from dimethyl-formamide, dimethylacetamide, hexamethylphosphotriamide, tetramethylene-sulphone and N-methylpyrrolidone of a polymer having an inherent viscosity from 0.4 to 1.6 and consisting essentially of amide-imide linkages of the formula or of said amide-imide linkages and of amide linkages of the formula - NH - AR1 - NH - CO - R - CO - in which R represent a divalent benzene radical, Ar1 represents a
Claim 2
Dependent Claim
112 words
Process for producing heat stable filaments and fibers which comprises extruding through a spinneret maintained at a temperature between 60* and 180* C in an evaporatory atmosphere maintained at a temperature near or above the boiling point of the solvent, a solution in an inert organic polar solvent selected from dimethyl-formamide, dimethylacetamide, hexamethylphosphotriamide, tetramethylene-sulphone and N-methylpyrrolidone of a polymer having an inherent viscosity from 0.4 to 1.6 and consisting essentially of amide-imide linkages of the formula or of said amide-imide linkages and of amide linkages of the formula - NH - AR1 - NH - CO - R - CO - in which R represent a divalent benzene radical, Ar1 represents a
Claim 3
Dependent Claim
24 words
Process according to claim 1, wherein the drawing temperature is near or above the temperature corresponding to the maximum algebraic value of said curve.
Claim 4
Dependent Claim
11 words
A process according to claim 1, wherein the solvent is N-methylpyrrolidone.
Claim 5
Dependent Claim
108 words
Process according to claim 1 which comprises extruding through a spinneret maintained at a temperature between 60* and 180* C. in an evaporatory atmosphere maintained at a temperature near or above the boiling point of the solvent, a solution in an inert organic polar solvent selected from dimethylformamide, dimethylacetamide, hexamethylphosphotriamide, tetramethylenesulphone or N-methylpyrrolidone of a polymer having an inherent viscosity from 0.4 to 1.6 and consisting essentially of amide-imide linkages of the formula or of said amide-imide linkages and Of amide linkages of the formula - NH - Ar1 - NH - CO - R - CO -in which R represents a divalent benzene radical, Ar1 represents a
Claim 6
Dependent Claim
19 words
Process according to claim 4 wherein the filaments are drawn at a drawing ratio from 3:1 to about 5.2:1.
Claim 7
Dependent Claim
21 words
A process according to claim 1 wherein the polyamide-imide solution has a viscosity of 300 to 6,000 poises at 25* C.
Claim 8
Dependent Claim
17 words
A process according to claim 1 wherein the polyamide-imide solution is 15 to 35 percent by weight.
Claim 9
Dependent Claim
16 words
A process according to claim 1 wherein the spinneret is maintained at 90* to 180* C.
Claim 10
Dependent Claim
15 words
A process according to claim 1 wherein the spinning speed is 100 to 400 m./minute.
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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |