US3920508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyolefin pulp and process for producing same
Assignee: Fort James Corp
•
Filing: 1972-10-05
•
Granted: 1975-11-18
•
Expires: 1992-10-05
Abstract
Abstract A polyolefin pulp suitable for papermaking is described which is formed of a mass of discrete fibers formed of convoluted strands, the convoluted strands being twisted or wound-up film or sheetlike elements, the pulp having a drainage factor greater than 1.0 seconds/gram and a compressability constant (N) between about 0.3 and 0.4. Further, a process of manufacturing such fibers by forming a dispersion (mixture) of a solvent, a polyolefin, a water dispersing agent for the pololefin fibers to be formed and water and flashing the mixture through a nozzle. Water is present as a continuous phase in the mixture. The polyolefin is crystalline, or partially crystalline, preferably polyethylene, polypropylene, copolymers of ethylene and propylene, and mixtures thereof. The fibers thus formed can be easily refined and used for making paper webs.
Inventors
- 👤 Hayato Yonemori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:04
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/11
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
179 words
A PROCESS FOR PRODUCING A POLYOLEFIN PULP COMPRISING FORMING A MIXTURE OF A POLYOLEFIN, A SOLVENT FOR THE POLYOLEFIN AT ELEVATED TEMPERATURES, WATER AS THE CONTINUOUS PHASE, AND POLYVINYL ALCOHOL DISSOLVED IN THE WATER, THE MIXTURE BEING AT A TEMPERATURE ABOVE THE MELT DISSOLUTION TEMPERATURE OF THE POLYOLEFIN IN THE SOLVENT AND AT SUBSTANTIALLY AUTOGENEOUS PRESSURE, THE POLYOLEFIN BEING PRESENT IN AN AMOUNT OF FROM ABOUT 0.5 TO 15 PERCENT BY WEIGHT OF THE SOLVENT, THE POLYVINYL ALCOHOL BEING PRESENT IN AN AMOUNT FROM ABOUT 0.1 TO 5 PERCENT BY WEIGHT OF THE POLYOLEFIN, THE SOLVENT BEING INERT AND STABLE AT THE MIXTURE TEMPERATURE AND SUBSTANTIALLY IMMISCIBLE IN WATER OR FORMING A POLYMER SOLUTION WHICH IS SUBSTANTIALLY IMMISCIBLE IN WATER; PASSING THE MIXTURE THROUGH A NOZZLE INTO A ZONE OF LOWER PRESSURE TO VAPORIZE THE SOLVENT AND FORM AN AQUEOUS SLURRY OF FIBROUS POLYOLEFIN, THE PRESSURE IN THE ZONE BEING SUCH THAT THE TEMPERATURE OF THE MIXTURE FALLS BELOW THE SOFTENING POINT OF THE POLYOLEFIN, AND; REFINING THE AQUEOUS SLURRY OF FIBROUS POLYOLEFIN INTO A PULP OF DISCRETE FIBERS.
Claim 2
Dependent Claim
179 words
A PROCESS FOR PRODUCING A POLYOLEFIN PULP COMPRISING FORMING A MIXTURE OF A POLYOLEFIN, A SOLVENT FOR THE POLYOLEFIN AT ELEVATED TEMPERATURES, WATER AS THE CONTINUOUS PHASE, AND POLYVINYL ALCOHOL DISSOLVED IN THE WATER, THE MIXTURE BEING AT A TEMPERATURE ABOVE THE MELT DISSOLUTION TEMPERATURE OF THE POLYOLEFIN IN THE SOLVENT AND AT SUBSTANTIALLY AUTOGENEOUS PRESSURE, THE POLYOLEFIN BEING PRESENT IN AN AMOUNT OF FROM ABOUT 0.5 TO 15 PERCENT BY WEIGHT OF THE SOLVENT, THE POLYVINYL ALCOHOL BEING PRESENT IN AN AMOUNT FROM ABOUT 0.1 TO 5 PERCENT BY WEIGHT OF THE POLYOLEFIN, THE SOLVENT BEING INERT AND STABLE AT THE MIXTURE TEMPERATURE AND SUBSTANTIALLY IMMISCIBLE IN WATER OR FORMING A POLYMER SOLUTION WHICH IS SUBSTANTIALLY IMMISCIBLE IN WATER; PASSING THE MIXTURE THROUGH A NOZZLE INTO A ZONE OF LOWER PRESSURE TO VAPORIZE THE SOLVENT AND FORM AN AQUEOUS SLURRY OF FIBROUS POLYOLEFIN, THE PRESSURE IN THE ZONE BEING SUCH THAT THE TEMPERATURE OF THE MIXTURE FALLS BELOW THE SOFTENING POINT OF THE POLYOLEFIN, AND; REFINING THE AQUEOUS SLURRY OF FIBROUS POLYOLEFIN INTO A PULP OF DISCRETE FIBERS.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein the polyolefin is a crystalline polyolefin selected from the group consisting of polyethylene, polypropylene, ethylene-propylene copolymers and mixtures thereof.
Claim 4
Dependent Claim
10 words
The process of claim 2 wherein the polyolefin is polyethylene.
Claim 5
Dependent Claim
37 words
The process of claim 3 wherein the molecular weight and concentration of the polyethylene in the solvent is selected to provide a solution viscosity at the temperature of the mixture between about 100 and about 3500 centipoises.
Claim 6
Dependent Claim
23 words
The process of claim 1 wherein the solvent to water volume ratio is between about 0.5 : 1 to about 2 : 1.
Claim 7
Dependent Claim
20 words
The process of claim 1 wherein the solvent has a boiling point lower than the melting range of the polyolefin.
Claim 8
Dependent Claim
158 words
A process for producing a polyolefin pulp comprising forming a mixture at a temperature between about 130*C and about 160*C and under substantially autogeneous pressure of a crystalline polyolefin, a solvent for the polyolefin at elevated temperatures, polyvinyl alcohol and water; the polyolefin being present in an amount up to 15 percent by weight of the solvent, the solvent to water ratio being between about 0.5 : 1 and about 2 : 1, the water bieng present as the continuous phase of the mixture the polyvinyl alcohol being present in an amount up to about 15 percent by weight of the polyolefin, the solvent having a boiling point lower than the melting range of the polyolefin and stable at the mixture temperature; passing the mixture through a nozzle into a zone of lower pressure to vaporize the solvent and form an aqueous slurry of fibrous polyolefin, and refining the firbrous polyolefin slurry into a pulp of discrete fibers.
Claim 9
Dependent Claim
158 words
A process for producing a polyolefin pulp comprising forming a mixture at a temperature between about 130*C and about 160*C and under substantially autogeneous pressure of a crystalline polyolefin, a solvent for the polyolefin at elevated temperatures, polyvinyl alcohol and water; the polyolefin being present in an amount up to 15 percent by weight of the solvent, the solvent to water ratio being between about 0.5 : 1 and about 2 : 1, the water bieng present as the continuous phase of the mixture the polyvinyl alcohol being present in an amount up to about 15 percent by weight of the polyolefin, the solvent having a boiling point lower than the melting range of the polyolefin and stable at the mixture temperature; passing the mixture through a nozzle into a zone of lower pressure to vaporize the solvent and form an aqueous slurry of fibrous polyolefin, and refining the firbrous polyolefin slurry into a pulp of discrete fibers.
References Cited (Backward Citations)
US896051A
Cited
US3042970A
Cited
US3081519A
Cited
US3244688A
Cited
US3219601A
Cited
US3542715A
Cited
US3402231A
Cited
US3432483A
Cited
US3342921A
Cited
US3386488A
Cited
US3770856A
Cited
US3743570A
Cited
US3743272A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |