Wuhan Handern Composite Sheet Extrusion Technology
DATE：2020/11/10 9:03:51 / READ： / SOURCE：This station
Wuhan Handern Composite Sheet Extrusion Technology
(1) Sheet extrusion process. On-line composite sheet extrusion is carried out in Jiangsu Jicheng Decoration Materials Co., Ltd. The three-layer co-extrusion composite board production line of Italy Unin Company is adopted. The diameter of the main screw is 120mm smaller, and the diameters of the two lateral screws are 70m and 45mm respectively. The die lip of the T-shaped head is controlled by a microcomputer with an accuracy of 0.1m. The extrusion temperature is controlled at 24 points, in which the temperature control of the main screw barrel is 16 sections, and the T-shaped die has 8 sections. The feed end starts at 190°C, the middle zone temperature is 22°C, the T-shaped die inlet end is 205°C, and the die lip outlet end is 195°C. The die lip gap is 2.3mm, and the distance between the die lip and the pressure roller is 20cm. After the sheet comes out of the die lip, it directly enters the lower roller, and enters the carriage line from the upper roller through the middle roller. The temperature of the three rolls is 90℃ for the bottom roll, 80℃ for the middle roll, and70°C. The PU-non-woven fabric sheet is pre-placed at the lower part of the first pressure roller near the side of the die lip. After the substrate extrusion process is stable, the distance between the three rollers is appropriately widened, and the sheet is fed into the first pressing roller from the underside of the extrudate to obtain a qualified composite board. . www.handern.com pet sheet equipment
(2) The main factors affecting the quality of composite panels. . www.handern.com pet sheet equipment
① Extrudate melt temperature. The temperature difference of the extrudate from the melt state into the cold press roll is large, which is easy to produce flow orientation and internal stress, especially when the die lip size is not well matched with the gap between the three rolls, the sheet will have a larger flow orientation Anisotropy. Therefore, it is very important to control the melt temperature of the extrudate. In principle, when the composite sheet can be extruded, the melt temperature of the extrudate should be reduced as much as possible. For PP and its multiphase blend system, it is better to control the melt temperature at 190℃～195℃. www.handern.com pet sheet equipment
②Control of the gap and temperature of the three rollers. Take the device where the extrudate enters the upper roll from the lower roll as an example. The gap between the bottom roll and the middle roll of the extrudate is mainly used to control the balance of the extrusion volume, and the gap between the middle roll and the top roll is mainly used to control the size of the sheet, and it can have the functions of glazing and printing patterns according to requirements. Generally, the gap between the middle and upper rollers is smaller than the gap between the lower and middle rollers. This is due to the cooling shrinkage of polymer materials, and the functional requirements of glazing and printing patterns. The temperature control between the three rollers is very important. The temperature of the three rollers decreases in turn, but note that if the roller temperature is too low, a large internal stress will be generated, resulting in a bow-shaped sheet. . www.handern.com pet sheet equipment
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