US4091058A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of fibrids from poly(amide-imide) resins
Assignee: BASF SE
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Filing: 1976-09-28
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Granted: 1978-05-23
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Expires: 1996-09-28
Abstract
Abstract Fibrids are prepared by introducing a solution of a polymer into a liquid precipitation medium while exposing it to shearing forces. A poly(amide-imide) resin solution is admixed with a solvent which is miscible with the resin solvent but which is a non-solvent for the resin itself.
Inventors
- 👤 Bruno Sander
- 👤 Kurt Scherling
- 👤 Rolf Steinberger
- 👤 Eckhard Ropte
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:25
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/40; D01F; D01F6/00; D01F6/88; D01F6/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
108 words
A process for the manufacture of fibrids by dissolving a poly(amide-imide) resin in an organic solvent and introducing the resulting solution into water while at the same time exposing it to shearing forces, in which process the solution of the poly(amide-imide) resin in an organic solvent is mixed, before its introduction into water, with a liquid in a volume ratio of said solvent to said liquid of from 1:1.5 to 1:5, said liquid being a non-solvent for the poly(amide-imide) resin but being homogeneously miscible in all proportions with water and with the organic solvent, and which liquid is selected from the group consisting of tetrahydrofurane and 1,4 dioxane.
Claim 2
Dependent Claim
108 words
A process for the manufacture of fibrids by dissolving a poly(amide-imide) resin in an organic solvent and introducing the resulting solution into water while at the same time exposing it to shearing forces, in which process the solution of the poly(amide-imide) resin in an organic solvent is mixed, before its introduction into water, with a liquid in a volume ratio of said solvent to said liquid of from 1:1.5 to 1:5, said liquid being a non-solvent for the poly(amide-imide) resin but being homogeneously miscible in all proportions with water and with the organic solvent, and which liquid is selected from the group consisting of tetrahydrofurane and 1,4 dioxane.
Claim 3
Dependent Claim
23 words
A process as claimed in claim 1 wherein said solvent is a member selected from the group consisting of 1-methyl-2-pyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.
Claim 4
Dependent Claim
40 words
A process as claimed in claim 2 wherein the solution of the poly(amide-imide) resin has a solids content of 5 to 35% by weight and a viscosity of of 2,000 to 200,000 cP, as measured by a falling ball viscometer.
Claim 5
Dependent Claim
75 words
A process as claimed in claim 1 wherein said poly(amide-imide) resin is a polymer containing recurring units having the formula ##STR3## where n is an integer, R' and R" are the same or different and respectively are m-phenylene, p-phenylene or ##STR4## and x is CH 2 , O, S, CO or SO 2 , said polymer optionally containing additional amide linkages of the formula --OC--R'--CONH--R"--NH-- in which R' and R" have the meanings given above.
Claim 6
Dependent Claim
32 words
A process as claimed in claim 1 wherein said shearing forces are created by mechanically rotated elements at given energy densities in the range of 20 to 80 watt. sec/cm 3 .
Claim 7
Dependent Claim
38 words
A process as claimed in claim 1 wherein said shearing forces are generated hydraulically at given energy densities in the zone in which the fibrids are formed in the range of 5 to 30 watt. sec/cm 3 .
Claim 8
Dependent Claim
50 words
A process as claimed in claim 1 wherein the fibrids formed have a length of from 0.1 to 5 mm, a thickness of from 5 to 200 μm, a Schopper-Riegler freeness of from 20 to 90 °SR and a specific surface area of from 1 to 80 m 2 /g.
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) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |