Calcium Zinc Stabilizer


Calcium and zinc stabilizers are usually divided into: solid calcium and zinc stabilizers and liquid calcium and zinc stabilizers.

Calcium-zinc stabilizer is synthesized by a special composite process with calcium salt, zinc salt, lubricant, antioxidant as the main components. It can not only replace toxic stabilizers such as lead-cadmium salts and organotin salts, but also has quite good thermal stability, light stability, transparency and tinting power. Practice has proved that in PVC resin products, the processing performance is good, and the thermal stability is equivalent to that of lead salts, and it is a good non-toxic stabilizer.

The appearance of calcium and zinc stabilizers is mainly white powder, flake, and paste. Powdered calcium and zinc stabilizers are used as the most widely used non-toxic PVC stabilizers, often used in food packaging, medical apparatus, wire and cable materials, etc. At present, PVC calcium and zinc stabilizers that can be used in rigid pipes have appeared in China.

The thermal stability of powdered calcium and zinc stabilizers is not as good as that of lead salts, and it has certain characteristics such as lubricity, poor transparency, and easy to spray frost. In order to improve its stability and transparency, antioxidants such as hindered phenols, polyols, phosphite esters and β-diketones are often added to improve it.

The two major systems of calcium and zinc stabilizers are mainly divided into hydrotalcite system and zeolite system.

The price of powdered calcium and zinc stabilizer is uneven, and there is no standardized national standard to regulate it.

The appearance of liquid calcium and zinc stabilizers is mainly light yellow oily liquid. There is little difference in the stability between powder and liquid. Liquid calcium and zinc stabilizers usually have greater solubility, and have good dispersibility in PVC resin powders, and have far less effect on transparency than powder stabilizers. However, there is a greater risk of precipitation of liquid stabilizers. A suitable solvent needs to be selected.

Liquid stabilizers are usually used for PVC products with a total amount of plasticizers greater than 10~ 20phr.

Metal soaps and auxiliaries have high solubility in solvents; low volatility, high flash point, low viscosity, colorless or light color, no odor, non-toxic or low toxicity. For example, mineral oils such as liquid paraffin, white oil, diesel oil, spindle oil are used as solvents. It is worth noting that some solvents contain polycyclic aromatic hydrocarbons. According to the relevant provisions of Section 30 of the German Food and Commodity Law (LMBG), the maximum allowable limit of total PAH is 10mg (10PPM), and the maximum allowable limit of BaP benzo (a) pyrene is 1mg (1PPM). Some countries in the European Union are also preparing to adopt this standard. Auxiliary stabilizers themselves do not have thermal stabilization functions, but they can improve stabilization efficiency, because there is no cadmium single-component assistance, the main phosphite esters, epoxy compounds, phenolic antioxidants, β-diketones and other auxiliary substances are obvious. Especially important.

It has good dispersion, compatibility, processing fluidity with PVC resin processing, wide adaptability, and excellent product surface finish; excellent thermal stability, small initial hue, no precipitation phenomenon; does not contain heavy metals and other toxic ingredients, no vulcanization phenomenon; Congo red test time is long, has excellent electrical insulation, no impurities, and has high efficiency and weather resistance; wide application range, strong practicability, low consumption, and versatility; in white products, whiteness is better than its congeneric products.

Varieties, specifications and uses

According to different uses, there are different varieties of calcium-zinc composite stabilizers: CZ-1, CZ-2, CZ-3, etc., which are used in pipes, profiles, pipe fittings, plates, injection molding, blown films, cable materials and other plastic products.

Problems that must be solved when calcium and zinc stabilizers replace lead salts

Liquid calcium and zinc stabilizer is a compound of calcium and zinc organic salts, phosphite esters, polyols, antioxidants and solvents. Liquid calcium and zinc stabilizer has good compatibility with resins and plasticizers, good transparency, not easy to precipitate, less dosage, and easy to use. The main disadvantage is poor lubricity, reducing the softening point of products, and deterioration during long-term storage.

The solid composite calcium-zinc soap stabilizer is mainly stearic acid soap, followed by lauric acid soap and oleic acid soap. The product is characterized by good lubricity, does not reduce the softening point of PVC hard products, and is suitable for the processing of rigid PVC pipes and profiles.

The products obtained and processed by microemulsification technology overcome the above shortcomings. People focus on improving from two aspects: in order to improve the initial coloring, with a sufficient amount of zinc soap, use a chelating agent to make zinc chloride harmless. This becomes a high zinc combination: reduce the amount of zinc soap to inhibit zinc burning, and use additives to change the initial coloring. This practice becomes a low zinc combination., not only widely used in soft products, its thermal stabilization effect and transparency have been recognized, but also successfully used in hard product processing. In order to keep the calcium/zinc system both small initial coloring and inhibit zinc burning.

Generally, the lead salt is only attached to the surface of the PVC particles, and its effect is equivalent to hindering the fusion between the PVC particles, which will significantly delay the plasticization, reduce the friction between the PVC particles, reduce the shearing effect in the PVC, and the processing equipment bears a lower load. The more lead salt is used, the finer the particles of lead salt, the more obvious the secondary effect.

Traditional environmental protection products such as calcium and zinc stabilizers, in the plasticizing process, due to the large electronegativity, the polar groups have a certain affinity with the acute nodes of PVC resin, forming a bond with strong bond energy, thereby weakening or eliminating the attraction of ionic bonds in each layer of PVC. The intertwined segments of PVC are easy to diffuse, and the boundaries between molecular groups are easy to be small, which promotes the plasticization of PVC resin. This leads to the rapid increase of melt pressure, decrease of melt viscosity, increase of temperature, and decrease of plasticizing temperature after the resin is partially plasticized in the feeding section.

In addition, because the traditional PVC processing equipment serves the processing of lead salt stabilizers, even adding a sufficient amount of lubricant cannot prevent the further plasticization of the resin in a sufficient time, and it also destroys the original lubrication balance. At the same time, the later PVC melt consumes a large amount of heat stabilizer in the homogenization section, but cannot achieve the ideal viscosity and elasticity to meet the production needs of rigid PVC. This is a problem that calcium-zinc stabilizers must solve in replacing lead salts.

CH400, CH401, CH402 calcium-zinc composite heat stabilizer is an environmentally friendly and efficient multi-functional liquid calcium-zinc composite heat stabilizer. Excellent thermal stability and transparency, it will not produce surface precipitation and migration when used in PVC products, and it is better to use with heat-resistant oil, epoxy methyl ester, and epoxy soybean oil. It is suitable for PVC slurry processing and is widely used in PVC processing processes such as slush molding, plastic coating, and dipping.

The product not only has good compatibility and viscosity control, but also provides good initial tinting and color retention. The product has been proven to be an excellent heat stabilizer. It has good solubility, low volatility, low mobility and good light resistance, and is suitable for PVC products industries such as soft pipes, granulation, calendered films, toys, conveyor belts, advertising cloths, wallpapers, etc.

(1) It can replace organotin stabilizers and lead salt-based stabilizers to meet the environmental protection and hygiene requirements of non-toxic wires and cables; (2) It has excellent initial whiteness and thermal stability, and is resistant to vulcanization pollution; (3) It has good lubricity and unique coupling effect, giving the filler good dispersion, enhancing the wrapping with resin, improving product performance, reducing mechanical wear, and prolonging the service life of the equipment; (4) It has both toughening and melting promotion, and has good plasticizing fluidity; (5) It can give the PVC mixture good uniform plasticization and high-speed melting fluidity, so that the surface of the product is smooth.

Recommended dosage: 2-5PHR of the total mixture


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Shandong Xieheng Plastic Auxiliaries Co., Ltd. has actively participated in a number of international plastic industry exhibitions in 2023, showing the company's strength and product diversification, and further expanding the international market.

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