| 摘要 |
PURPOSE:To produce effectively the film with high rigidity by following method in which specially determined sorbitol derivative is added to the high crystalline PP having the isotactic pendat fractional ratio for insoluble part of special boiled heptan and the content ratio for soluble part thereof, and then it is made in film and is drawn. CONSTITUTION:High crystalline polypropylene contains more than 0.955 isotactic pentad fractionl ratio for the insoluble part of boiled heptan and less than 9wt% content ratio for soluble part of said heptan. 0.05-1.0wt part sorbitol derivative (e.g. dibenzylidene sorbitol etc.) shown by formula (R is alkyl radical of H, C1-18 or alkoxy radical of C1-4) is added to 100wt part high crystalline polypropylene and is mixed. Then, the mixture is extruded at molten state, after it is pelletized by a pelletizing machine and it is rapidly cooled by cooling rolls. Next, the sheet obtained is drawn at least in the direction of one axis and the objective film is produced. |
