US4642262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making fibrids from thermoplastics
Assignee: PIOTROWSKI BERNHARD A
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Filing: 1984-03-09
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Granted: 1987-02-10
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Expires: 2004-03-09
Abstract
Abstract Disclosed is a method of making fibrids from thermoplastics synthetics and copolymers thereof by expanding by vaporization, in the presence of a gaseous propellant, a polymer solution under elevated pressure and elevated temperature in a mixing nozzle under shear inducing conditions wherein the true or apparent solution of the polymer in solvent is expanded by the use of superheated steam having an average energy density of at least 50 watt-seconds per cubic centimeter in the mixing nozzle.
Inventors
- 👤 Bernhard Piotrowski
- 👤 Robert Buning
- 👤 Bernhard Janser
- 👤 Egon Lang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:13
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/11; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2904; Y10T442/00; Y10T442/60; Y10T442/69
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
78 words
A method of making fibrids from thermoplastic synthetic substances comprising expanding by vaporization, in the presence of a gaseous propellant, a polymer solution, under elevated pressure and elevated temperature, in a mixing nozzle having a Laval discharge portion under shear-inducing conditions, wherein the true or apparent solution of the polymer in a solvent is expanded by the use of superheated steam at an average energy density of at least 50 watt-seconds per cubic centimeter in the mixing nozzle
Claim 2
Independent Claim
78 words
A method of making fibrids from thermoplastic synthetic substances comprising expanding by vaporization, in the presence of a gaseous propellant, a polymer solution, under elevated pressure and elevated temperature, in a mixing nozzle having a Laval discharge portion under shear-inducing conditions, wherein the true or apparent solution of the polymer in a solvent is expanded by the use of superheated steam at an average energy density of at least 50 watt-seconds per cubic centimeter in the mixing nozzle
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein the steam velocity is at least ten times the velocity of the polymer solution.
Claim 4
Dependent Claim
23 words
The method of claim 1, wherein the steam velocity is at least 300 ms -1 , preferably 400 to 800 ms -1 .
Claim 5
Dependent Claim
21 words
The method of claim 1, wherein the mass ratio of the steam to solvent is a maximum of 3:1, preferably 1:1.
Claim 6
Dependent Claim
58 words
The method of claim 1, wherein the fibrids are made from PVDF, PVC or copolymers of PVDF or PVC with a content of at least 50 wt.-% of PVDF or PVC, and acetone as solvent, the solution having a temperature of 90° to 150° C. and the concentration of the polymer ranging from 0.5 to 35% by weight.
Claim 7
Dependent Claim
37 words
The method of claim 1, wherein the thermoplastic synthetic is selected from the group comprising polyolefins, polyvinyl halides, polyvinylidene halides, other polymers on the basis of vinyl derivatives, polyamides, polyesters, polyacrylonitrile, polyurethanes, their copolymers and the like.
Claim 8
Dependent Claim
15 words
The method of claim 1, wherein the mixing nozzle is a two substance mixing nozzle.
Claim 9
Dependent Claim
10 words
An article produced according to the method of claim 1.
Claim 10
Dependent Claim
18 words
An article of claim 8, wherein the article is a porous sheet material, mat or other filtration means.
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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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |