How to do waste plastics processing?
Waste plastics recycling is conducive to environmental protection, saving resources. Thermoplastic waste is of good valueRenewable resources, which can be recycled, granulated or modified and then granulated, can be used again to produce plastic products.First, the characteristics of waste plasticsWaste plastics can be divided into three types according to the occasions they are produced. One is the waste material produced in the production processWaste material is clean, less pollution and contain impurities, such as film production of substandard film, cutting edge, PP flatIn the production of silk silk, pipes and profiles in the production of material or part of the unqualified products, injection production in underfilled partsAnd so on. One kind is used, material system single plastic waste, such as the demolition of pipes, doors and windows, through strictSorting of packaging materials or other waste plastics products according to the type of resin; and another is difficult to distinguish or impossibleSeparate mixed waste plastics such as multilayer co extruded composite films, coated plastic products, plastics and other materialsSynthetic products, etc..
Different kinds of waste plastics have different characteristics. As far as impurity content is concerned, waste materials in the middle and outer corners of the factory produce impuritiesThe content is less than 0.1%, the leftover material and other used products are piled up for a certain time, and the impurity content is 0.1% ~0.5%, mixed with aluminum, cloth and paper composite waste plastics, impurities are often greater than 10%. For used waste plastics,Depending on the conditions of use, ultraviolet radiation, the effects of heat and oxygen aging, and the effects of pollutants are includedRing. For different shapes of waste plastics, the volume density of materials after crushing is very different, film, sheet, flatThe volume density of the crushing material is smaller, which is a problem that must be considered in the process of waste plastics recycling and granulation.
For the cleaning and crushing before granulation, there are three processes as follows.1. first cleaning and then crushing processLarge plastic waste products with little pollution and complicated structure should be cleaned first and then broken, such as automobilesBumpers, dashboards, turnover boxes, plates, etc. First with detergent water immersion, then rinse with water, removeAfter drying. Due to the large size and can not be placed into the crusher hopper larger parts, should be broken after rough crushing, ready to squeezeA granulator feeding. In order to ensure the quality of recycled aggregate, it should be dried after fine crushing, usually with heating interlayerIn the rotary dryer, the superheated steam is inserted in the interlayer, and the drying efficiency is higher when the edge is heated and rotated.
Two. Pretreatment of waste plasticsWaste plastics from waste packages such as bags, shopping bags, bottles, cans, boxes, and waste agricultural filmsPretreatment prior to granulation. The pretreatment process mainly includes classification, cleaning, crushing and drying.Classification work is the classification of miscellaneous waste plastics products according to the type of raw materials and product shapes classification. By raw materialsClass sorting requires operators to have a good knowledge of identifying plastic varieties, and the purpose of sorting is to avoid different speciesThe resulting polymers are incompatible with recycled materials and have poor performance. They are classified according to the shape of the product to facilitate the use of waste plasticsThe crushing process can be carried out smoothly, because the film, flat and fabric used in crushing equipment with some thick and hard wareThe crushing equipment often can not replace each other.
