US3882095A
Expired / Lapsed
US
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Process for forming polyolefin fibers
Assignee: Fort James Corp
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Filing: 1972-03-16
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Granted: 1975-05-06
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Expires: 1992-03-16
Abstract
Abstract The process of forming polyolefin fibers comprising polymerizing an olefin in a solvent or dissolving a high molecular weight polyolefin in the solvent at a temperature above the melt dissolution temperature of the polyolefin to be formed, and cooling the reaction mass to a temperature below the melt dissolution temperature to form a fibrous gel containing polyolefin microfibrils, macrofibrils and fibers.
Inventors
- 👤 Robert W Fowells
- 👤 Robert A Damon
- 👤 James G Coma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:37
CPC Classifications
B; B01; B01J; B01J3/00; B01J3/04; B01J19/00; B01J19/18; D; D01; D01D; D01D5/00; D01D5/38; D01D5/40; B01J2219/00; B01J2219/00002; B01J2219/00027; B01J2219/00033; B01J2219/00049; B01J2219/00051; B01J2219/00074; B01J2219/00087; B01J2219/00094
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
128 words
A PROCESS FOR PREPARING POLYOLEFIN FIBERS COMPRISING FORMING A SOLUTION OF A POLYOLEFIN IN A SOLVENT AT A TEMPERATURE ABOVE THE MELT DISSOLUTION TEMPERATURE OF THE POLYOLEFIN, SUBJECTING THE POLYOLEFIN SOLUTION TO A SHEAR STRESS OF GREATER THAN ABOUT ZERO POUNDS (FORCE)FT2 UP TO ABOUT 6.25 POUNDS (FORCE)FT2 WHILE COOLING THE POLYOLFIN SOLUTION TO A TEMPERATURE BELOW THE MELT DISSOLUTION TEMPERATURE OF THE POLYOLEFINE, THE MAGNITUDE OF SAID SHEAR STRESS BEING SUFFICIENTLY GREAT TO PRECIPITATE THE POLYOLEFIN AS A FIBROUS GEL HAVING INTERCONNECTING CAPILARY SPACES FILLED WITH SOLVENT INTERTWINED WITHIN A FIBRILLAR STRUCTURE OF FIBROUS POLYOLEFIN, AND SUBSEQUENTLY SUBJECTIG THE FIBROUS GEL FORMED DURING COOLING TO A SHEAR STRESS OF GREATER THAN ABOUT 0.1 POUND (FORCE/FT2 THEREBY PRODUCING DISCRETE, DIRECTLY RECOVERABLE, POLYOLEFIN FIBERS WITHOUT REQUIRING FURTHER PROCESSING STEPS.
Claim 2
Dependent Claim
128 words
A PROCESS FOR PREPARING POLYOLEFIN FIBERS COMPRISING FORMING A SOLUTION OF A POLYOLEFIN IN A SOLVENT AT A TEMPERATURE ABOVE THE MELT DISSOLUTION TEMPERATURE OF THE POLYOLEFIN, SUBJECTING THE POLYOLEFIN SOLUTION TO A SHEAR STRESS OF GREATER THAN ABOUT ZERO POUNDS (FORCE)FT2 UP TO ABOUT 6.25 POUNDS (FORCE)FT2 WHILE COOLING THE POLYOLFIN SOLUTION TO A TEMPERATURE BELOW THE MELT DISSOLUTION TEMPERATURE OF THE POLYOLEFINE, THE MAGNITUDE OF SAID SHEAR STRESS BEING SUFFICIENTLY GREAT TO PRECIPITATE THE POLYOLEFIN AS A FIBROUS GEL HAVING INTERCONNECTING CAPILARY SPACES FILLED WITH SOLVENT INTERTWINED WITHIN A FIBRILLAR STRUCTURE OF FIBROUS POLYOLEFIN, AND SUBSEQUENTLY SUBJECTIG THE FIBROUS GEL FORMED DURING COOLING TO A SHEAR STRESS OF GREATER THAN ABOUT 0.1 POUND (FORCE/FT2 THEREBY PRODUCING DISCRETE, DIRECTLY RECOVERABLE, POLYOLEFIN FIBERS WITHOUT REQUIRING FURTHER PROCESSING STEPS.
Claim 3
Dependent Claim
25 words
The process of claim 1, wherein the fibrous gel formed is subsequently subjected to shear stress forces by passing the gel through a disc refiner.
Claim 4
Dependent Claim
18 words
The process of Claim 2, wherein the polyolefin has a viscosity average molecular weight greater than about 40,000.
Claim 5
Dependent Claim
15 words
The process of claim 2, wherein the polyolefin has a melt index of essentially zero.
Claim 6
Dependent Claim
23 words
The process of claim 2, wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene and copolymers of ethylene and propylene.
Claim 7
Dependent Claim
26 words
The process of claim 2, wherein the solvent has a solubility parameter such that ( delta s - delta p)2 is less than about 3.0 cal/cc.
Claim 8
Dependent Claim
18 words
The process of claim 2, wherein the fibrous polyolefin is in the form of microfibrils, macrofibrils and fibers.
Claim 9
Dependent Claim
48 words
The process of claim 7, wherein the majority of the microfibrils have a diameter less than about 1.0 micron, the majority of the macrofibrils have a diameter between about 1 and about 20 microns and the majority of the fibers have a diameter greater than about 10 microns.
Claim 10
Dependent Claim
40 words
The process of claim 2, wherein the polyolefin solution is formed by polymerizing an olefin in the presence of a coordination catalyst system in the solvent at a temperature above the melt dissoluton temperature of the polyolefin to be formed.
Claim 11
Dependent Claim
14 words
The process of claim 9, wherein the coordination catalyst is of the Ziegler type.
Claim 12
Dependent Claim
43 words
The process of claim 10, wherein the Ziegler type catalyst comprises a catalyst selected from the group consisting of titanium trichloride, titanium tetrachloride, vanadium tetrachloride and vanadium oxytrichloride, and a cocatalyst selected from the group consisting of diethyl aluminum chloride and triethyl aluminum.
Claim 13
Dependent Claim
21 words
The process of claim 9, wherein the polymerization temperature is between the melt dissolution temperature and the temperature of molecular randomization.
Claim 14
Dependent Claim
13 words
The process of claim 9, wherein an excess of monomeric olefin is employed.
Claim 15
Dependent Claim
25 words
The process of claim 9, wherein the olefin is gaseous and the reaction medium is saturated with the olefin prior to introduction of the catalyst.
Claim 16
Dependent Claim
27 words
The process according to claim 9, wherein the polymerization is carried out in the absence of chain transfer agents to form a polyolefin of high molecular weight.
Claim 17
Dependent Claim
14 words
The process of claim 2, wherein a preformed polyolefin is dissolved in the solvent.
Claim 18
Dependent Claim
25 words
The process of claim 2, wherein the fibrillar structure of the fibrous gel produced during cooling is essentially in the form of macrofibrils and fibers.
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) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |