| 摘要 |
PURPOSE:To obtain a molded item of an ultra-high-molecular weight polypropylene whose tensional modulus is not less than 10GPa and whose breaking strength is not less than 0.6GPa, by heating a polypropylene having a viscosity-average molecular weight of not less than 1,000,000 in a solvent to dissolve the polypropylene, separating a single crystal appregate from the resulting solution, removing the solvent and subjecting the aggregate to stretching. CONSTITUTION:A polypropylene having a viscosity-average molecular weight of not less than 1,000,000, preferably of 2,000,000 and more is dissolved in a solvent by heating, a single crystal aggregate of the polypropylene is separated from the resulting solution, the solvent is removed from the aggregate to form a matlike product, and the product is stretched. From this an ultra-high-molecular weight polypropylene molded item having a tensional modulus of not less than 10 gigapascals and a breaking strength of 0.6 gigapascals and more can be obtained. Therefore it is quite suitable as a lightweight material wherein a high elasticity and a high strengh are required such as films and fibers. |
