Stabilizing additives are used in chemical industry. What are the properties and classification of stabilizing additives when they are used?

There are many types of PVC processing aids.  The purpose of PVC processing aids is to clamp the PVC plastics in accordance with the specification, so that the PVC processing aids will produce a chemical reaction to the PVC materials, resulting in a better atomization effect. , to achieve its high quality plasticity. During the process of molding, storage, and use of plastics, the physical and mechanical properties are gradually degraded due to the intrinsic factors and the sum of external environments, until they finally lose their use value.  This phenomenon is called plastic aging. Intrinsic factors include the chemical structure and physical configuration of the resin polymer itself; external factors include light, heat, air (oxygen), microbes, and the like. The pros and cons of plastics aging depends on internal and external factors.  Additives added to retard or suppress this destructive effect are collectively referred to as stabilization aids.  When we process PVC materials, commonly used PVC processing aids include heat stabilizers, light stabilizers, antioxidants, and anti-mold agents.

The purpose of understanding PVC processing technology is to obtain a product that has the best mechanical properties, weatherability and appearance properties. Only by understanding PVC processing technology can we develop the best PVC processing aid products. To this end, it must first be understood that the PVC product performs best under what conditions. It is generally believed that the optimum degree of plasticity of PVC is between 65-70%. That is, the best performance occurs when only 30% to 35% of PVC is present in the particulate state. In theory, because of the characteristics of PVC, vinyl chloride cannot be dissolved in vinyl chloride solution after polymerization and is in the form of suspended particles. As the polymerization proceeds, the particles grow slowly until the monomers are consumed. The large particles of PVC are composed of numerous small particles. The plasticization of PVC in production is the breaking of large particles into small particles and melting into the molecular chains of PVC. It can be said that the mechanical properties of PVC products must be related to the plasticizing state of PVC. When the PVC particles are all melted and plasticized into PVC molecular chains, the mechanical properties of the products should be the best. The more unrecovered large particles remain, the worse their mechanical properties. Why, then, is the general PVC plasticity of 65-70%, the best mechanical test results? This is because of the poor thermal stability of PVC. The degree of plasticization of PVC reaches 100% and requires a very high temperature or a long period of time. During this time, PVC will be decomposed in large amounts and the performance will be decreased.