PVC, or polyvinyl chloride, is a widely used thermoplastic polymer that can be found in a variety of products, including pipes, cables, flooring, and upholstery. However, PVC is thermally unstable at processing temperatures, and without the addition of stabilizers, it can degrade and lose its mechanical properties over time. Therefore, stabilizers are an essential component of PVC formulations. This blog will guide you through the exploration of various types of stabilizers and their applications.
Types of Stabilizers in PVC
Ba-Zn Stabilizer
Ba-Zn stabilizers are used in PVC to enhance thermal stability and improve the physical properties of the material like promoting foams and producing uniform bubble structure. They are cost-effective and provide excellent processing stability. Ba-Zn stabilizers are also known for their low toxicity and environmental friendliness.
Ba-Cd-Zn Stabilizer
Ba-Cd-Zn stabilizers are similar to Ba-Zn stabilizers. They are effective in improving the weather ability and impact resistance of PVC. Moreover, its lubrication system can prevent bleeding during processing or printing as well.
Ca-Zn Stabilizer
Ca-Zn stabilizers are non-toxic and environmentally friendly. They are used in PVC to improve heat stability, processability, and mechanical properties. They can effectively improve the processing efficiency and prevent bleeding during the process. Ca-Zn stabilizers are also effective in reducing the cost of PVC production.
K-Zn Stabilizer
K-Zn stabilizers are a type of mixed metal stabilizer that contains potassium and zinc. They are used in PVC plastics to improve stability, promote foaming and produce uniform bubble structure. K-Zn stabilizers are also known for their low toxicity and environmental friendliness.
TiO2
TiO2 is a white pigment that is commonly used in PVC as a stabilizer and a UV absorber. It is effective in improving the wearability and light stability of PVC.
Azodicarbonamide
Azodicarbonamide is a blowing agent that is used in PVC to increase the porosity and reduce the density of the material. It is effective in improving the thermal insulation properties of PVC.
DOA
DOA (dioctyl adipate) is a plasticizer that is used in PVC to improve fluidity by reducing the intermolecular forces within the polymer matrix. It is effective in maintaining the flexibility of PVC at low temperatures. DOA is also employed in adhesives, sealants, and coatings to improve their adhesion properties.
Anti-blocking Agent
Anti-blocking agents are used in PVC to improve the flowability, dispensability of the material and prevent it from sticking to itself by creating a thin layer between particles.
Calcium Stearate
Calcium stearate is a lubricant that is used in PVC to improve the flowability of the material. It is effective in reducing the friction and wear of PVC during processing. Calcium stearate is also known for improving the surface finish of rubber products.
Zinc Stearate
Zinc stearate is a stabilizer and a lubricant that is used in PVC as a release agent, thickening agent and emulsifier. It also boasts good heat resistance, excellent transparency, yellowing resistance, quick drying and increased standability.
Functions of Stabilizers
Stabilizers are essential additives in PVC to prevent its degradation during processing and use. They protect PVC from the harmful effects of heat, UV radiation, and mechanical stress. In this section, we will discuss the three main functions of stabilizers in PVC: heat stability, UV resistance, and processing stability.
Heat Stability
Heat stability is one of the most important functions of stabilizers in PVC. When PVC is exposed to high temperatures, it can undergo thermal degradation, which results in discoloration, loss of mechanical strength, and reduced performance. Stabilizers prevent this degradation process by scavenging and neutralizing free radicals produced during thermal decomposition. They act as antioxidants, protecting the polymer from oxidation and thermal degradation.
UV Resistance
PVC is susceptible to degradation caused by UV radiation from sunlight. This degradation process can cause discoloration, cracking, and loss of mechanical properties. Stabilizers protect PVC from the harmful effects of UV radiation by absorbing and dissipating the energy from UV rays. They act as UV absorbers, preventing the formation of free radicals that can cause degradation.
Processing Stability
Stabilizers also play a crucial role in maintaining the processing stability of PVC. During processing, PVC is subjected to high temperatures and shear stresses, which can cause degradation and reduce the quality of the final product. Stabilizers prevent this degradation process by reducing the viscosity of the melt and improving the flow properties of PVC. They act as lubricants, reducing friction between the polymer chains and improving the processability of PVC.
In summary, stabilizers are essential additives in PVC, with three main functions: heat stability, UV resistance, and processing stability. They protect PVC from thermal degradation, UV radiation, and mechanical stress, ensuring the quality and performance of the final product.
Applications
PVC stabilizers play a crucial role in enhancing the durability, functionality, and safety of products across various industries.
PVC Film
In the packaging industry, film applications require stabilizers to resist the degrading effects of heat and light. These stabilizers extend the life of PVC film used in food packaging and bags, ensuring they do not release harmful substances and maintain their mechanical properties over time.
PVC Artificial Leather
PVC artificial leather utilized for upholstery, fashion, and automotive applications demands consistent performance. Here, stabilizers improve the material’s resistance to wear and tear and their balanced internal and external lubrication effectively improves processing efficiency.
Coating Line Product
Stabilizers play a pivotal part in coating line products such as AC foaming agents and promote foaming, which reduces the degradation temperature. It is eco-friendly because they do not contain heavy metal cadmium, and meet the standards of REACH, RoHS, EN-71, etc.
The harmonized use of PVC stabilizers across these applications serves not only to prolong the functionality of the products but also to ensure safety and performance in line with industry standards.