| 摘要 |
PURPOSE:To obtain the polyolefin family sheet excellent in impact resistance by rolling crystalline polyolefin family resin in biaxial direction under the temperature condition satisfying the formula, keeping the time equal to 30min or more. CONSTITUTION:It is necessary that rolling temperature T is in the range of Tms-5 deg.K<=T<=Tms+5 deg.K, and preferably in the range of Tms-3 deg.K<=T<=Tms+ 3 deg.K. here, T; rolling temperature, Tms: the melting point of sheet or block like material before rolling. In said temperature range, material must be rolled, while keeping the time equal to 30min or more, and its rolling must be carried out in biaxial direction. This sheet has not the defect of imferior adapting to a mold, and also there is not the sag impeding the process, when a large molded product is produced by vacuum molding or pressure molding. Consequently, the impact resistance of the sheet is heightened, and also its strength and Young's modulus are improved. As the molecular structure of polyolefin has no necessity of denaturation, its original characteristics such as mechanical strength, electrical property, water resistance and chemicals resistance are kept as they are. |
