Process for treatment of olefin polymer fibrils
AssigneeGulf Oil Corporation
InventorWilliam H. Gonzales
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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.degree. 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.
Claims9
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.degree. C.
Dependencies are inferred from the claim text.