Pvc lubrifiant is divizat în două categorii: intern lubrifiant și extern lubrifiant, dar diviziune de intern și extern lubrifiere is only relativ, there is no strict division standard, the main distinction is based on the size of the lubrifiant and rășină compatibilitate. Intern lubrifiere și rășină afinitate, sale rol is to reduce the intermolecular force, improve the dispersion of raw paper components; external lubrifiant and rășină affinity is small, its role is to reduce the friction between the resin and metal surfaces.
Due to the different polarity of the resin, the role of internal and external lubricants may change. În general vorbind, polar lubrifianți astfel as stearic acid alcool, stearic acid amidă, stearic acid butil ester și stearic acid monogliceride are clasificat as intern lubrifianți, while less polar lubricants such as parafină ceară și pe ceară classified as external lubrifianți, this is for the polar pvc and pa rășini, and the result is just the opus for the the non-polar resins such as pe and pp. Parafină ceară, pe ceară și pe, pp rășină are non-polar substanțe, have good compatibilitate, so it is a tipic intern lubrifiant.
The compatibilitate între lubrifiant și rășină is not constant, but changes with the processing temperature. Astfel ca stearic acid și stearil alcool pentru PVC extrudare turnare la începutul din temperatura topită este scăzută% 2c și PVC rășină compatibilitate este sărac % 2c în principal joacă rolul rolul of external lubrifiant; când temperatura crește, și pvc compatibilitate crește, mici molecule de lubrifianți sunt mai ușor de pătruns în lanțul molecular între lubrifiantul este schimbat în un intern lubrifiant rol.
Lubricant properties also change with the amount of its addition. When the amount of lubricant added is less than the degree of compatibility, there is no washing out of the pvc secondary particles outside the obvious internal lubrication, when the amount of lubricant added is greater than the degree of compatibility, part of the excluded in the pvc macro-particles and secondary particles outside the external lubricating effect of the obvious. Stearic acid is the most widely used lubricant after metal soap. It is a typical external lubricant in soft products, which can well reduce the friction heat generated by the resin and processing equipment, and can also well prevent the adhesion of the molten resin to the metal surface. However, in pvc-u, when the dosage is small, it plays the role of internal lubrication, which can obviously promote plasticization and reduce the viscosity of the melt; when the dosage is large, it can obviously slow down the speed of plasticization and play the role of external lubrication.
In view of the lubrifiant, especially metal soap lubricants in a certain temperature, pressure, shear heat, and the compatibility of pvc resin changes. In fact, foarte few lubricants are simply slippery or slippery, that a certain lubricant is slippery or slippery, refers to a certain situation in accordance with the regular addition is mainly lubrifiant or lubrifiant mainly outsidely outsidely.
The main reason why alkanewaxes are generally used as external lubricants is that they have little polarity and have a small degree of compatibility with extremely polar resins. înainte plastifiere, it uniform acoperit în the surface of pvc particule, so that the particule slide each other, hinder the expansion of the particle segment chain with each other, aderență, întârziat plastifiere; in the plastization, it is excluded from the outer surface of the the melt and the formation of liquid lubrifiant film, reducing the pvc melt and processing equipment metal surface adhesion and friction, thereby Reducerea fenomenul local supraîncălzire, îmbunătăți Termic Stabilitate și Mobilitate A Pvc Rășină.
