| 摘要 |
PURPOSE: To prevent the neck-in phenomenon, the irregularity in the thickness, and the leakage of drip-like solid resin of molten resin by providing a roll member at the part of a chill roll in contact with both the back edges of a molten sheet immediately after extrusion from a lip port between the port and the roll. CONSTITUTION: A roll member 5 for extruding in the direction for reducing at least a drawdown angle is provided at the part of a chill roll 3 in contact with both the back edges of a molten sheet directly after extruding from a lip port 2 is provided between the port 2 of a T die 1 and the roll 3. As a result, neck-in can be prevented, and the irregular thickness can be prevented as well. The difference of the drawdown angles at the back edges and the center of the sheet is normally 1 to 17 deg.. The member 5 is preferably made at the surface of fluorine resin, and it is desired to form the holding mechanism 6 of the member in the structure capable of regulating the drawdown angle in the case of bringing the member into contact with the sheet. The distance from the port 2 to the member 5 is set to about 30 to 100mm according to the size of the roll 3 and the line speed. |
