Classification and selection of lubricants in plastics industry
April 09, 2024
Classification and selection of lubricants in plastics industry We all know that plastics in the process of heating and melting molding, will be driven by mechanical force and shear force agitation, plastic and plastic, plastic and machinery will produce a variety of friction, friction will produce heat, and too much friction will produce friction heat, so that the temperature of the plastic core can not be derived and the phenomenon of burning and bubbles.
Therefore, in the plastic processing process, it is generally necessary to add lubricants to reduce the attraction between polymer molecules, so as to improve its fluidity, and reduce the adhesion of the surface of the product and the effect of plastic adhesion. In addition to improving fluidity, lubricants can also play the role of melting accelerator, anti-adhesion agent, anti-static agent, and slippery agent. Understanding the significance of the existence of lubricants, we will look at its classification and function. There are two main types of lubricants: internal lubricants and external lubricants 1. The main role of internal lubricant and external lubricant The main function of the internal lubricant is to weaken the interaction between the internal chain segments of the polymer, so that the polymer molecules are easy to slide, improve the fluidity of the polymer melt, such lubricants and polymer molecules have compatibility, can be evenly distributed around the polymer molecules, such as, common processing AIDS: stearic acid The main function of the external lubricant is to make the surface of the product good luster, the product is easy to release, to prevent the surface of the product from sticking, they have poor compatibility with the resin, can not be evenly dispersed around the resin molecules, can not be dispersed in the interior. The amount of external lubricant should not be too much, too much easy to make the surface frosting or sticky. For example, polyethylene wax 2. Main functions of internal lubricant and external lubricant The function of the internal lubricant is mainly to weaken the attraction between the macromolecular chains, make the molecular chains easy to slide, and reduce the interface friction; Smooth gelation of powder resin; Reduce the melt viscosity of resin and improve the fluidity of resin; Increase production capacity and reduce mechanical load. The main function of the external lubricant is to reduce the local overheating of the resin and aging decomposition; Improve the gloss of the surface of plastic products; Make the product easy to demoulding, prevent the product from sticking with the mold surface. Common varieties of lubricants Excellent lubricant? How to choose? 1) Good dispersion, easy to disperse evenly; 2) Suitable compatibility with polymers. Too large, will play a plastic, plastic softening; Too small, will frost or damp on the surface; 3) Good thermal stability, no volatilization, no decomposition, no discoloration at the processing temperature, and different components react; 4) Non-toxic, colorless, tasteless, no migration; 5) Low price, easy to get.
