Basic knowledge of PVC product production process

Problems that should be paid attention to in compounding materials

In the process of PVC resin, various additives should be added to improve the performance of PVC to meet the needs of processing and product performance. In the production of plastic door and window profiles, it is generally necessary to add heat stabilizers, processing modifiers, impact modifiers, lubricants, light stabilizers, fillers and pigments. Although the amount of additives added is 0.1% to 10% of the PVC resin, their respective roles are very important. It can be said that none of them are indispensable, and the change of the added amount has a great impact on the processing and the performance of the final product. Big. Therefore, not only the ingredients must be accurately weighed, but also the mixing process must be evenly mixed to achieve the consistency of the materials.

Material preparation

The preparation process of PVC materials mainly includes batching, hot mixing, cold mixing, transportation and storage. The methods include small-scale production methods of manual batching and manual transportation, and large-scale production methods of automatic batching and automatic transportation. In recent years, my country’s hard PVC profile extrusion industry has entered a period of rapid development. The scale of the company continues to expand. For companies with an annual output of 10,000 tons, the use of artificial ingredients for material processing methods can no longer meet the needs of mass production. Process automation has become a commonly used method. The automatic method of material processing is generally suitable for professional profile production plants with a production capacity of more than 5,000 tons. Its labor intensity is low, the production environment is good, and human errors can be avoided, but the investment is large, the system maintenance cost is high, the system cleaning is difficult, and the formula is not suitable The frequent changes, especially color changes. Enterprises with a production capacity of less than 4,000 tons often use manual ingredients, transportation, and mixing. The biggest problem of artificial ingredients is high labor intensity, dust pollution is formed in the ingredients and mixing, but the investment is small and the production is flexible.

The automation of material processing refers to a computer-controlled automatic batching system as the core, supplemented by pneumatic conveying, and then combined with hot and cold mixers to form a complete PVC batching and mixing production line. This technology was introduced to our country in the mid-1980s and was applied in some large enterprises of a certain scale. The advantages of this technology are high batching precision, high production efficiency, and less pollution, which can meet the needs of mass extrusion production. At present, some factories in our country can produce this kind of computer-controlled automatic batching system.

Ingredients are the first process of mixing. The key to ingredients is the word “quasi”. In large modern enterprises producing plastic profiles, most of the ingredients adopt a computer-controlled multi-component automatic weighing system. The more widely used method is weighing measurement. According to different weighing methods, it can be divided into batches of cumulative weighting, loss-in-weight weighting and continuous weighting of flowing process materials. The batch-to-batch accumulative weighing method is very harmonious with the batch-to-batch feeding and mixing working method required in the mixing process, and is most suitable for the compounding of PVC, so it is used more in the production of PVC profiles.

Post time: Mar-11-2021