The advantage of PVC calcium zinc composite stabilizer

The advantage of PVC calcium zinc composite stabilizer

As the environmental protection consciousness gradually strengthened, the traditional PVC stabilizers such as powdered lead salt stabilizer, barium, cadmium stabilizer is limited by some, has been correspondingly developed environmental protection PVC composite calcium zinc stabilizer, with excellent performance to win the broad market, widely used in building materials, light industry, agriculture, packing, electric power, public utilities and other departments, especially in the construction of plastic, agricultural areas such as plastics, plastic packaging materials, daily occupies an important position. The advantages of green PVC calcium zinc stabilizer are introduced.

Pure PVC resin for heat sensitive, when heating temperature reached 90 y: above, mild thermal decomposition reaction, occurs when the temperature rises to 120 oC after decomposition reaction,  in 150oC, for 10 minutes, PVC resin is the original white gradually become yellow, red, brown, black. The decomposition of PVC resin is caused by a series of chain reactions caused by the dehcl reaction, resulting in the rupture of the large molecular chain. The thermal stability mechanism of PVC thermal decomposition is achieved through the following aspects.

(1) to prevent the catalytic degradation of HCl by capturing HCl produced by PVC pyrolysis. Lead salt is mainly based on this mechanism, as well as metal soap, organic tin, phosphatides and epoxides.

(2) permutation of active allyl chloride atoms. Metal soap, phosphite and organic tin can be used as the mechanism.

(3) react with free radicals to terminate free radical reactions. Organic tin and phosphite are acting on this mechanism.

(4) the addition of conjugate double bonds can inhibit the growth of the conjugated chain. The organic tin and epoxies play a role in this mechanism.

(5) decompose peroxide, reducing the number of free radicals. Organic tin and phosphite are acting on this mechanism.

(6) passivating metal ions that catalyze the removal of HCl.

The same compound heat stabilizer can achieve the thermal stability in several different mechanisms.