US4374788A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for treatment of olefin polymer fibrils
Assignee: Chevron USA Inc
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Filing: 1979-02-28
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Granted: 1983-02-22
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Expires: 1999-02-28
Abstract
Abstract Fibrils prepared by a differential temperature precipitation process of the type described in U.S. Pat. No. 4,013,751 are refined in isopropanol at a subambient temperature not higher than about 10° C., and subsequently are treated with an aqueous solution of polyvinyl alcohol to sorb at least 1.0 weight % of polyvinyl alcohol on the fibrils. The treated fibrils, as compared with fibrils prepared by prior art processes disperse more readily in aqueous media and provide water-laid sheets having greater strength. The fibrils preferably are prepared from an olefin polymer having a weight average molecular weight of at least one (1) million.
Inventors
- 👤 William H. Gonzales
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:21
CPC Classifications
D; D21; D21H; D21H5/00; D21H5/12; D21H5/20; D21H5/202; D01; D01F; D01F6/00; D01F6/02; D01F6/04; D21H13/00; D21H13/10; D21H13/12; D21H13/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
92 words
In a process in which olefin polymer fibrils are prepared by: a. Cooling a hot olefin polymer solution under conditions of high shear to prepare fibrils, b. Recovering the precipitated fibrils, c. Refining the fibrils in the presence of a low molecular weight oxygen containing liquid, and d. Treating the fibrils with an aqueous solution of polyvinyl alcohol to sorb at least 1 weight % of polyvinyl alcohol on the fibrils, the improvement which consists of carrying out the refining step (c) at a subambient temperature not higher than about 10° C.
Claim 2
Dependent Claim
92 words
In a process in which olefin polymer fibrils are prepared by: a. Cooling a hot olefin polymer solution under conditions of high shear to prepare fibrils, b. Recovering the precipitated fibrils, c. Refining the fibrils in the presence of a low molecular weight oxygen containing liquid, and d. Treating the fibrils with an aqueous solution of polyvinyl alcohol to sorb at least 1 weight % of polyvinyl alcohol on the fibrils, the improvement which consists of carrying out the refining step (c) at a subambient temperature not higher than about 10° C.
Claim 3
Dependent Claim
28 words
The process of claim 1 in which the refining step (c) is carried out at a temperature in the range of about -20° C. to about 10° C.
Claim 4
Dependent Claim
35 words
The process of claim 2 in which the step (d) of treating the refined fibrils with a solution of polyvinyl alcohol also is carried out at a subambient temperature not higher than about 10° C.
Claim 5
Dependent Claim
22 words
A process of claim 1 in which the low molecular weight oxygen containing liquid employed in step (c) is n-propanol or isopropanol.
Claim 6
Dependent Claim
22 words
A process of claim 2 in which the low molecular weight oxygen containing liquid employed in step (c) is n-propanol or isopropanol.
Claim 7
Dependent Claim
22 words
A process of claim 3 in which the low molecular weight oxygen containing liquid employed in step (c) is n-propanol or isopropanol.
Claim 8
Dependent Claim
20 words
A process of claim 1 in which the low molecular weight oxygen containing liquid employed in step (c) is isopropanol.
Claim 9
Dependent Claim
20 words
A process of claim 2 in which the low molecular weight oxygen containing liquid employed in step (c) is isopropanol.
Claim 10
Dependent Claim
20 words
A process of claim 3 in which the low molecular weight oxygen containing liquid employed in step (c) is isopropanol.
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) | 1986-02-21 | 1986-08-23 | 1987-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-21 | 1990-08-23 | 1991-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-21 | 1994-08-23 | 1995-02-22 | $7700.00 | Window Closed / Lapsed |