Polyvinyl chloride (PVC, full name: Polyvinyl chloride) from ethylene and hydrogen chloride (calcium carbide route) or ethane, ethylene and chlorine (petrochemical route) to the synthesis of vinyl chloride monomer, and then polymerization into polyvinyl chloride resin. According to polymerization process can be divided into the body, suspension, emulsion, solution and other polymerization products, of which more than 80% of the suspension polymerization products, emulsion polymerization resin accounted for 10%, mainly for paste materials. Main body polymerization Yibin Tian Yuan chemical plant to introduce French technology, at present only in the preliminary preparation. Solution polymerization resin dosage is not much, domestic has not this product.
At present, the suspension polymerization resin of our country is divided into seven kinds of products according to the molecular weight, and each kind is divided into compact type and loose type according to its granule shape. Resin particle size of about $number micron, they are composed of countless 0.1 microns, the size of the particles condensed into, some particles of the entire surface has a layer of "skin film" covered, the skin membrane is more solid, more difficult to destroy, which is close-type resin, its plasticizer infiltration ability is poor. The "skin film" of the loose resin is thin and not all covered, it is advantageous for the plasticizer to infiltrate the inside of the granule, it is arranged into the random structure, and the crystallinity is at most $number (which includes a small amount of 20% per cent crystallinity).