At present the estimates production capacity in PVC resin, mostly 111 million pounds are small amounts of copolymer norbornene-type homopolymers and. Accounts for about 90 percent of the total by the suspension method, the rest being born a bulk polymerization and emulsion legal system, the king has prepared part mushy resin. But a small amount of solution copolymer is not included.

These products widely potential applications, is in the process of the polymerization, add a little polymerization additive, which affect the structure and performance of resin particles. As in suspension method, add some production resin water-soluble polymer with background dispersants or auxiliary dispersant, and latex resin combination by surfactant things.

Other general additives have sting mixture, antioxidants, slow granule, or simple alkali. Domestic resin is expected to have moderate growth, the future will largely depend on economic development cycle and the strength of the U.S. dollar.

All commercial use PVC is by addition polymerization reaction production. Polymerization process, generate free radical molecules initiator. And with the surrounding green vinyl monomer together to form a activity center. Reaction to continue until chain terminated. In trials are conditions, a separate PVC molecular complete chain growth needed to complete required almost only a small part time shift. This reaction is autocatalytic reaction, have been polymer molecular weight of initiator almost and the degree of concentration and chain transfer is irrelevant. Because the reaction process is in isothermal conditions, forming narrow polydispersity (MWD is very typical. In this reaction in the chain molecules in the average, estimated to be around 950 (122 ° F polymerization temperature) and 480 (158 ° F for polymerization temperature between.

Polymerization is completed, the polymer molecular mainly according to head a tail sequence. Polymer is part between gage), crystallization (with the rise of temperature, the structure without regular sex also sport is on the increase. About 60% of the polymer molecular will exist of unsaturated chain end, it mainly depends on the way, and termination of chain branched function may take place in 4% of the chain molecules. These factors on the thermal stability of the resin impact, when reaction temperature rises, with chain transfer these factors are increasing needs higher than chain letter about.

Want special attention is, hard PVC first ° F in nearly 212 occurring thermal decomposition, it mainly depends on molecular weight and heating conditions. In release hydrogen, resin will discoloration, brittle, finally for crosslinking and become not sexual material. Resin discoloration is due to thermal sensitive ene can and the formation of uncle chlorine atom, molecular chain rupture, causing many ene structure formation of generation.

Usable stabilizer to improve the mix ingredients and final products of the thermal stability, several materials can be used as stabilizers such as metal organic compounds, metal salt and metal soap). Antioxidants, radical inhibitors.

Can and main stabilizers on synergy auxiliary stabilizers is also effective. Other physical properties, PVC glass transition temperature (Tg) can think 5 link segments of temperature, hard start activities of PVC resin is 180 ° believed Tg).

As plasticizers, gradually to increase the value in the lower Tg. Although melting heat at a plastic systems is increasing, but due to measurement of the thermal stability of reason, this kind of resin is the melting point can't be measured directly.

For PVC with the valid range increment of polymers with mutual mix soluble plastic in paste resin, often adding plastic agent, its dosage can from a very low level, so the level to the very variety products can be prepared of PVC.

These compounds reduced molecule room bunch of force, and make the product more soft.

Plasticizer usually runs primarily plasticizer, auxiliary plasticizer or incremental agent, mainly depends on the compatibility of level, with polymer ratio of 1:1 say incompatible, auxiliary plasticizers mainly plasticizer compatible ratio within 1-3.

These materials leak lesser, volatile tendency is lower. Also many plasticizer is resistant to degrade, non-flammable, in chemistry is inert.