After a comprehensive analysis of the original production process of the plant, I believe that there are many reasons for the quality problems of the filter plate, in which the production process is a very important factor, for this filter plate production process to study. Filter Plate According to GB / T5283 requirements, Filter Plate plastic filter plate, filter box at room temperature physical and mechanical properties should meet the following requirements: tensile strength greater than or equal to 26MPa; bending strength greater than or equal to 41MPa; notched impact strength greater than or equal to 6.86kJ / ㎡; heat distortion temperature greater than or equal 110 ° C (0.64 MPa).
As the raw materials in the water exceeded, Filter Plate especially PP is easy to moisture, so the raw materials must be dry before mixing. PP, CaCO3, talcum powder placed in the oven at 100 ~ 110 ℃ drying 1 ~ 1.5h.
Calculate the amount of coupling agent based on the mass of the material and dilute the coupling agent with analytically pure alcohol. But note that the diluted concentration should not be less than 20%. After adding the coupling agent, the coating can be formed on the surface of a certain thickness of the coating, the coating and the filler has a good combination, but also with the matrix resin has good compatibility, Filter Plate when subjected to external force, the filler And the matrix resin at the same time deformation and absorption of impact energy, to achieve the coordination of rigidity and toughness.
The dry PP, CaCO3, Filter Plate talc powder in proportion to the high-speed mixer, sealed open, start the motor, from the low speed gradually increase the speed to 750r / min, mixed 15 ~ 20min after the power. Wait 3 ~ 4min after opening the sealing cover, adding coupling agent, so that it evenly dispersed to the material surface. And then close the sealing cover, high-speed mixing 20 ~ 30min. Remove the material, Filter Plate into the oven at 100 ℃ again dry 0.5 ~ 1h.
Before the extrusion granulation, should be about 1h in advance of the twin-screw extruder preheat. The temperature of each zone is set as follows: the three sections of the feeding section are 200, 210, 215 ℃, the compression section is 220 ℃, the head is 220 ℃. Since the melting point of pure PP is 183 ° C, Filter Plate the melt temperature is set to 185 to 200 ° C so that the actual temperature is greater than 183 ° C so as to increase the melt flowability and increase the extrusion speed, Filter Plate but it is important to note that the warm- , So that the melt due to high temperature and yellowing, or even charred.
Before cleaning, remove the residue left in the barrel, cleaning the screw. After the temperature of the twin screw extruder reaches the preset temperature, Filter Plate a small amount of pure PP is added to the hopper, open the cooling circulating water, and then turn on the lubrication, vacuum, host and feed. Filter Plate After the pure PP in the hopper is added, the mixed dry material is added and the speed of the feed and the host is continuously adjusted during the extrusion process to increase the production efficiency. Feeding too fast will appear flash phenomenon; too slow will break material, accompanied by a strong friction between the friction of the friction, and also produce a lot of friction heat to raise the material temperature, Filter Plate resulting in the material in the barrel to turn yellow. Filter Plate Adjust the host speed of 300r / min, while the feed speed varies depending on the change in the feed hole. Pay attention to observe the melt temperature, so that it is not less than 183 ℃, Filter Plate nor higher than 210 ℃, in order to avoid plasticization or aging, resulting in reduced product performance.