Analysis of the main raw materials for the production

The main raw materials for the production of PVC heat shrinkable film are: PVC resin, plasticizer, stabilizer, modifier and lubricant. The last article mainly explained PVC resin. Today, I will introduce the remaining four types: plasticizers, stabilizers, modifiers and lubricants:

Plasticizer is one of the important additives in the processing of PVC heat shrinkable materials. It can reduce the force between polymer molecules, increase the plasticity of the polymer, and improve the molding performance of PVC. The amount of plasticizer should not be too much, otherwise the mechanical properties of the film will be reduced, the shrinkage stress of the film will be reduced, and the shrinkage rate will be affected.

PVC has good characteristics, but it also has shortcomings, one of which is poor thermal stability. The function of the stabilizer is to inhibit or prevent the thermal degradation of PVC during processing, and to extend its service life. The heat stabilizer should not affect the color and transparency of the product, and has good compatibility with resins and plasticizers, and is non-toxic and cost-effective. Low cost and small dosage.

In the production of PVC heat shrinkable film, the amount of plasticizer added is small, so it is difficult to plasticize. The method of increasing the plasticizing temperature will increase the possibility of thermal decomposition of PVC. Adding an appropriate amount of ACR processing modifier to the formulation can improve processing performance. ACR and PVC resin have similar solubility parameters, good compatibility, and greater adhesion between the two. ACR has a greater hardness than PVC. Under a certain stress, it produces greater friction, which makes the PVC particles easier to break and melt. The gelation speed and melting quality of the material are improved, and the melt strength is high.

The position of lubricants in polymer processing is also very important. In the production of PVC heat shrinkable film, an appropriate amount of lubricants should also be added to reduce harmful friction and reduce interfacial adhesion. According to the mechanism of the lubricant, adjust the internal , The matching amount of external lubricants to reduce matching costs. Stearic acid and oxidized polyethylene wax have carboxyl and hydroxyl polar groups on the molecular chain, which can significantly improve the compatibility of PVC and have a unique internal and external lubrication effect.