Patent US4025593A successfully refreshed from Google Patents.
US4025593A
Expired / Lapsed
US
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Fabrication of discontinuous fibrils
Assignee: Hercules LLC
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Filing: 1975-06-09
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Granted: 1977-05-24
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Expires: 1995-06-09
Abstract
Abstract A continuous fibrillated structure, formed by the abrupt pressure release of a two-phase liquid mixture of polymer and solvent at elevated temperature and pressure so as to cause the instantaneous vaporization of the solvent, is shredded by introducing a make-up fluid into the two-phase liquid mixture before the pressure release is complete.
Inventors
- 👤 Carlo Raganato
- 👤 Georges Voituron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:09
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/11
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
146 words
In a process for the manufacture of a fibrillated structure by the abrupt pressure release of a liquid mixture of molten polymer and solvent which is at a temperature and pressure such as to be in the form of a system of two phases consisting of a continuous liquid phase, which is poor in polymer and a second liquid phase dispersed therein which is rich in polymer, the abrupt pressure release taking place in a device which creates high losses and bringing about the instantaneous vaporization of the solvent and the solidification of the said polymer normally in the form of a continuous fibrillated structure, the improvement which comprises introducing a diluent fluid into the two-phase liquid mixture in the device before the pressure release is completed so that the abrupt pressure release results in the production of discontinuous fibrils instead of a continuous fibrillated structure.
Claim 2
Dependent Claim
146 words
In a process for the manufacture of a fibrillated structure by the abrupt pressure release of a liquid mixture of molten polymer and solvent which is at a temperature and pressure such as to be in the form of a system of two phases consisting of a continuous liquid phase, which is poor in polymer and a second liquid phase dispersed therein which is rich in polymer, the abrupt pressure release taking place in a device which creates high losses and bringing about the instantaneous vaporization of the solvent and the solidification of the said polymer normally in the form of a continuous fibrillated structure, the improvement which comprises introducing a diluent fluid into the two-phase liquid mixture in the device before the pressure release is completed so that the abrupt pressure release results in the production of discontinuous fibrils instead of a continuous fibrillated structure.
Claim 3
Dependent Claim
26 words
A process as defined in claim 1, wherein the diluent fluid is introduced into the two-phase liquid mixture before the abrupt pressure release of the latter.
Claim 4
Dependent Claim
14 words
A process as defined in claim 1, wherein the diluent fluid is a gas.
Claim 5
Dependent Claim
13 words
A process as defined in claim 3, wherein the diluent fluid is nitrogen.
Claim 6
Dependent Claim
14 words
A process as defined in claim 1, wherein the diluent fluid is a vapor.
Claim 7
Dependent Claim
14 words
A process as defined in claim 5, wherein the diluent fluid is water vapor.
Claim 8
Dependent Claim
14 words
A process as defined in claim 1, wherein the diluent fluid is a liquid.
Claim 9
Dependent Claim
15 words
A process as defined in claim 7, wherein the diluent fluid is water under pressure.
Claim 10
Dependent Claim
15 words
A process as defined in claim 8, wherein the diluent fluid contains a wetting agent.
Claim 11
Dependent Claim
27 words
A process as defined in claim 1, wherein the diluent fluid is identical with the solvent used for making the two-phase liquid mixture to be released abruptly.
Claim 12
Dependent Claim
35 words
A process as defined in claim 1, wherein the diluent fluid is at a temperature between 20° C. and its boiling point at the pressure at which it is injected into the two-phase liquid mixture.
Claim 13
Dependent Claim
29 words
A process as defined in claim 1, wherein the ratio between the volume of diluent fluid introduced and the volume of two-phase liquid mixture is from 0.3 to 10.
Claim 14
Dependent Claim
26 words
A process as defined in claim 1, wherein the polymer is selected from the group consisting of polyolefins, polyamides, polyesters, polyurethanes, polycarbonates, vinyl and acrylic polymers.
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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) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |