| 摘要 |
PURPOSE:To contrive to prevent the dispersibility of film or sheet from becoming not uniform by a method wherein dispersion or mixture of powdered ultra-high- molecular polyethylene in organic solvent is kept above a certain temperature. CONSTITUTION:Firstly, dispersion or mixture containing 10-60wt% of polyethylene is prepared by adding powder of ultra-high-molecular polyethylene with mean molecular weight of one million or more in organic solvent. Secondly, the dispersion or mixture is kept at a temperature of 80 deg.C or higher in order to allow the ultra-high-molecular polyethylene to absorb some portion of the organic solvent. Thirdly, the dispersion or mixture is melted by being heated up to the temperature above the melting temperature of the dispersion or mixture in order to be extruded in the shape of film or sheet. Finally, the resultant film or sheet is heated in order to volatilize the organic solvent and, after that, cooled. The organic solvent is added to improve the workability of the polyethylene. If the content of the polyethylene is less than 10wt%, the strength of extrude is decreased, while if more than 60wt%, the extrusion if uniform film or sheet becomes difficult. In addition, if neither heating nor heat retaining of the dispersion of mixture is performed, the unsmooth bite of an extruder is resulted. |
