Introduction of PVC plastic profiles

China's plastic profile heat stabilizer system mainly includes lead salt, organotin, calcium zinc and its composite stabilizer. Lead salt stabilizer is the most widely used stabilizer in the production of plastic doors and windows in China. It has the advantages of low price and good stability. However, due to the toxicity of lead, although it is not directly in contact with human body, it still poses a potential threat to the environment and human health. . PVC is resistant to acid and alkali corrosion. Hard PVC without plasticizer is not easily decomposed by mold. However, some PVC profiles and doors using lead salt stabilizers lose their luster after 1 to 2 years, after 3 to 4 years. Some surfaces have chalking.

This may be due to the fact that a component of the formulation reacts with sulfides in moist air to degrade the doors and windows. In addition, in the United States and other places, lead-salt is used as a stabilizer to add more than 10 parts of PVC plastic doors and windows of ultraviolet shielding agent titanium dioxide. After a period of time, the lead-containing resin powder formed by decomposition of the resin is found on the surface of the plastic profile. This has been confirmed by NASA's Space Flight Center and the military Aberdeen Test Center for the use of lead stabilizers for hard PVC doors and windows in North America.

In China's PVC profile lead salt stabilizer formulation system, the amount of titanium dioxide used is only about 1/2 of the amount of foreign addition, so the photoaging is severe, resulting in easy discoloration and further formation of lead-containing powder. Lead salt stabilizers and other sulfur-containing components in the formulation, such as fillers and colorants, may also react to coloration, and care should be taken when formulating the formulation system. In the recycling process, PVC containing lead stabilizers can also cause this drawback if a feed or scrap containing a thiol tin stabilizer is added.