Extrusion molding of plastic plates (sheets)
DATE：2022/11/3 8:34:34 / READ： / SOURCE：This station
Extrusion molding of plastic plates (sheets)
Table 7-7 Performance indexes of PP diaphragmNote: The change rate of longitudinal dimension is not considered for the sheet with thickness less than 0.5mm.
⑤ The filter screen has three layers of 40/80/40 mesh. The 80 mesh filter screen should be placed in the middle of the filter screen with small mesh to increase its strength.
⑥ The working surface of the three calendering rolls shall be plated with hard chromium, and the surface roughness R shall not be greater than 0.1 μ m. The surface shall be smooth and clean without air holes.
⑦ The distance between the three roll calender and the die lip shall be controlled within the range of 50~150mm, and the distance shall be adjusted according to the shrinking size of the width during production.
⑧ The working surface temperature of calender roller is adjustable, and the temperature of each position on the roller surface is consistent, and the temperature is controlled within ± 0.5 ℃.
⑨ The rotational speed of the roller matches the speed of the film extruded from the die lip. Generally, the rotational speed of the roller is 10%~20% faster than the flow rate of the film extruded from the die lip.
⑩ The finished diaphragm can be rolled or cut according to the user's requirements.
7.3 PVC sheet (sheet) extrusion molding
(1) Raw materials for PVC sheet (sheet) extrusion molding: rigid suspension method SG4 or SG5 PVC resin as the main raw materials; The suspension method SG2 or SG3 PVC resin is used as the main raw material for soft materials, and stabilizer, plasticizer, filler and other auxiliary materials are properly added according to the application conditions of the product to form the raw material formula. The food packaging is made of hard sheet and sanitary PVC resin. See Table 4-8 for the formula of extrusion materials for different plates (sheets). Extrusion molding formula of soft tablets (by weight): PVC SG2 100, tribasic lead sulfate (3PbO) 3, dibasic lead phosphite (2PbO) 1, dioctyl phthalate (DOP) 30, dibutyl phthalate (DBP) 25, PVC plates (tablets) are extruded. The specifications of the extruder are also suitable for colorants.
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