Preparation Of PVC Slush Powder And Characterization Of Its Structure And Performance

More and more instrument panels of top-grade cars are likely to use the skins produced with polyvinyl chloride (PVC) slush powder by slush molding. Although PVC powder slush molding is already quite mature in the last century, it is new progress in recent years by using it to make car dashboard skins. The special material is produced by just a few companies in the world now, and there is little relevant literature information about its formula and preparation technology. But the slush molding is a novel technique for us, and the special material mainly relys on import. In this paper, the key-technology of PVC slush powder preparation was investigated in a full-scale, and powder’s structure and performance were characterized comprehensively.Compared with traditional injection and extrusion molding, PVC slush powder molding demands higher thermal stability of PVC. Therefore, in this paper, at first, the thermal stability formula system of PVC slush powder was studied. The thermal stability and combination effect of stabilizers and co-stabilizers using in PVC blends were studied by oven test method and thermo-gravimetry (TG) and finally a good stabilizer-blend was gained with better thermal stability than that of parallel sample.PVC slush powder contains a lot of plasticizer and other organic additives, and they are easy to constantly move into the surroundings and make the products become hard and brittle in the process of long-term use, thus the products’ performance and life span are seriously affected; at the same time, do harm to human health. The hot air loss of plasticizer and the influence on plasticizer hot air loss by adding inorganic nanoparticles, powdered acrylonitrile-butadiene (PNBR) and beta-cyclodextrin was mainly studied; in addition, the impacts of other liquid ingredients in the formulation on the air loss of PVC slush powder were also studied. On this basis, each component was optimized, and got a formula with less hot air loss.PVC slush powder is prepared by dry mixing technology, and a high speed mixer is as mixing equipment. The absorption of plasticizer by PVC resins and the dispersible uniformity of all additives are the keys. Various process parameters about heat-mixing and cold-mixing was mainly studied, including charging sequence, rotating speed, mixing temperature, holding time and dispersant. On this basis, the appropriate process conditions was determined, then PVC slush powder with excellent comprehensive performance was gained.