Ingredients and mixing process. The quality of PVC compound preparation can reflect the extrusion speed of the extruder, the main parameters of the processing technology and the product quality, so this process should be strictly implemented. When batching, the ingredients in the formula should be measured to prevent the actual formula from being changed due to excessive measurement deviation, thereby increasing the difficulty of quality analysis and quality management. This point is often overlooked in the actual processing process and should be paid great attention.

1. Mixing temperature. Mixing is usually carried out in high speed mixers. The material generates heat by high-speed friction in the mixer. During the mixing operation, temperature adjustment is critical. Two points should be paid special attention to in temperature control: First, after the PVC resin and additives are put into the mixer, start stirring immediately, and use friction to heat up. When the temperature exceeds 120T, the material can be discharged into the cold mixer; Mixing in the cold mixer for a certain period of time, when the material temperature is lower than 45°C, the cold mixer gate can be opened to discharge the material.

2. Mixing time. During the mixing process, the material undergoes density transition, uniformity and partial gelation and other operations. At the same time, the removal of water and volatile matter in the material takes a certain period of time to complete. If the mixing time is too short, the extrusion process will be difficult, the material melting time will be long, and the quality of the product will be deteriorated; if the mixing time is too long, the temperature will rise too high, which will easily cause discoloration and decomposition of the material, and consume a lot of energy and low productivity. .

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Rigid PVC Sheet