Plastic Film Processing Plastics Additives and Applications

Plastic additives are added during the processing and use of plastic films. Because some of the resin or film products do not have the inherent performance to meet the requirements of their processing technology. Adding auxiliaries only needs to change their processability; while some materials have better processing performance, but the performance of the products does not meet ours. Requirements, it is also necessary to add additives to change its product performance. Of course, these two effects are mutually reinforcing, sometimes for the purpose of achieving both. Here we first introduce additives that can change the performance of plastic packaging films.

General requirements for additives

Compatibility In general, the additive only has good compatibility with the resin, so that the additive can exist in the film for a long time, stably and uniformly, and effectively perform its function. If the compatibility is not good, the "migration" phenomenon easily occurs. Performance in the liquid additive is "sweating", showing "blooming" phenomenon in solid additives. But sometimes when the film is less stringent, it can still allow its lack of compatibility, such as the compatibility between the filler and the resin is not good, but as long as the filling of the small particle size, it can still meet the performance requirements of the film, of course, if Treating it with a coupling agent or a surfactant will give fuller play to its function. However, some auxiliaries such as an opener, an antistatic agent, etc., which improve the surface properties of the film, are required to have a slight mobility so that they function on the surface of the film.

Durability Durability requires the long-term presence or absence of additives in the film with little or no loss, and the loss of adjuvants is mainly through three routes: volatilization, pumping, and migration. This is mainly related to the molecular weight of the auxiliary, the solubility in the medium and the solubility in the resin. The adaptability to the processing conditions The processing conditions of some resins are more severe, such as high processing temperature, this time should consider whether the selected additives will be decomposed, and whether the additives have any corrosive effect on the processing equipment.

The use of film for the constraints of additives for different uses of the film on the odor, toxicity, weather resistance, thermal properties, etc. have certain requirements. For example, plastic bags containing foods are non-toxic because they are different from the additives used in plastic bags for general packaging.

In the same resin system, the synergies and phase reactions in the auxiliary agents are combined, and some of the two auxiliary agents produce a “synergistic effect”, that is, they have more functions than a single additive. However, if it is not properly formulated, some auxiliaries may produce “phase interactions,” which will impair the function of each auxiliaries and even render certain auxiliaries ineffective. This should be particularly noted, such as carbon black and amines or phenols. The use of antioxidants can produce antagonistic effects. Plastic packaging film commonly used performance additives

Plasticizers and heat stabilizer plasticizers, as the name implies, increase the plasticity of the material, ie, it is added to the resin. On the one hand, the fluidity of the resin is increased during molding, and the processing performance is improved. On the other hand, the film after the manufacture can be made. Increased flexibility and elasticity of the substance.

The thermal stabilizer is an additive added for the purpose of improving the thermal stability of the resin. Mainly used for the processing of polyvinyl chloride and vinyl chloride copolymers. Light stabilizer polymer materials will rapidly age under sunlight, light and high-energy radiation, showing yellowing, brittleness, cracking, loss of luster on the surface, mechanical properties and electrical properties are also greatly reduced, and eventually lost. Use value. In this complex destruction process, ultraviolet light is the main cause of aging effects on polymer materials. It is mainly the result of the joint effect of ultraviolet light in the sun and oxygen in the atmosphere on polymer macromolecules.