Because PVC processing aids are highly compatible with PVC and have a high relative molecular weight (about (1-2) × 105-2.5 × 106g/mol) and no coating powder, they are subject to heat and mixing during the molding process. They first soften and tightly bond the surrounding resin particles. Through friction and heat transfer, melting (gel) is promoted. The viscosity of the melt does not decrease, or even increase; Due to the entanglement of molecular chains, the elasticity, strength, and extensibility of PVC have been improved.
In addition, due to the fact that the compatible and incompatible parts of PVC constitute processing aids with a core-shell structure. As a whole, it is incompatible with PVC and therefore serves as an external lubricant, but does not precipitate and forms scales, which has a delaying effect on melting. Therefore, based on these application characteristics, PVC processing aids can be divided into two categories: universal and lubricating. The function of universal PVC processing aids is to reduce melting temperature, enhance thermal strength and uniformity, reduce melt fracture, and impart greater ductility. These functions have great benefits for PVC processing: reducing the melting temperature means extending the thermal stability time, providing a safety factor for the utilization of recycled materials, and allowing for further processing; Improved thermal strength and reduced melt fracture, which means it can increase processing speed, accelerate traction, and also improve apparent quality and formability; Improved the uniformity of the melt, which can minimize the surface ripples and melt rupture of the extruded material, thereby increasing productivity, enhancing ductility and thermoformability.
Post time: Sep-05-2024
