PVC smērviela is sadalīts divās kategorijās: iekšējais smērviela un ārējā smērviela, but the division of internal and external lubrication is only relative, there is no strict division standard, the main distinction is based on the size of the lubricant and resin compatibility.
Iekšējais eļļošana un sveķi afinitāte, tā loma ir samazināt starpmolekulārais spēks, uzlabot izkliede izkliede no izejmateriāla komponentiem; ārējā smērviela un sveķi afinitāte is small, tā role is samazināt samazināt berze starp the resin and metal virsmām.
Sakarā ar atšķirīgo polaritāti of the resin, the role of internal and external lubricants may change. Vispār, the extremely strong lubricant such as stearic acid alcohol, stearic acid amide, stearic acid butyl ester and stearic acid monoglyceride are listed as internal lubricant, and the less polar lubricant such as paraffin wax and PE wax are listed as external lubricant, who is for for the extremely strong PVC and PA resins, and the result is just the opposite for the non-polar resins such as PE and PP. Parafīns vasks, PE vasks un PE, PP sveķi are nepolāras vielas ar labs saderība, so it is a tipisks iekšējais smērviela.
saderība starp smērviela un sveķi ir nav konstante, bet izmaiņas ar apstrāde temperatūra. Tāds as stearīns skābe un stearils spirts lietots in PVC ekstrūzija formēšana at sākums, dēļ to zems kausējums temperatūra, un PVC sveķi saderība ir slikts, galvenokārt rotaļas loma of ārējā smērviela; kad temperatūra paaugstinās, un PVC saderība palielinās, maza molekula smērviela ir vieglāk enter starp the molekula ķēde, it kļūst loma of iekšējais smērviela.
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 molten resin to metal surfaces. However, in PVC-U, when the dosage is small, it plays the role of internal lubrication, which can obviously promote the plasticisation and reduce the viscosity of the melt; when the dosage is large, it can obviously slow down the speed of plasticisation and play the role of external lubrication.
In view of the lubricant, especially metal soap lubricants in a certain temperature, pressure, shear heat, and the compatibility of PVC resin changes. In fact, very few lubricants are purely internal or external slip, that a certain lubricant is internal or external slip, refers reis a certain situation in con accordance with the conventional add is galvenokārt ietvaros the lubricity, or outside the lubrication of the main.
