The amount of lubricant some introductory

Lubricant actual processing plastics with a variety of effects, such as the kneading , rolling processing , to prevent adhesion polymer cartridge , inhibition of friction and heat, reduce kneading torque and loads, thus preventing polymer material thermal degradation . In the extrusion molding, to improve mobility , the barrel and the polymeric material to improve adhesion of the mold , to prevent and reduce the  impact modifier retentate . Another film can improve the appearance and luster. From processing machinery perspective, mixing, rolling , slush molding , etc. , the external lubricant has an important role in extrusion, injection molding, lubricants is more effective.
The amount of lubricant is generally 0.5 % to 1% , selection should pay attention to the following aspects : ( 1 ) the flow properties of the polymer molding technology needs have been met , the primary role of lubrication considerations to ensure that internal and external balance ;
( 2 ) external lubrication is valid , it can be in the molding temperature, the surface layer of the plastic film to form a complete liquid prevail , so the melting point of the lubricant outside the molding temperature should be close, but to a difference of 10 ℃ ~ 30 ℃ order to form a complete film ;
( 3 ) When the lubricant is selected in production , so as to be meet the following requirements:
( 4 ) compatibility with the resin medium size, internal and external lubricating balance ; non-blooming , easy to scale ;
( 5 ) Small surface gravity , viscosity, at the interface scalability, and easy to form the interface layer ;
( 6 ) as far as possible without compromising the excellent performance of the polymer does not affect the performance of the secondary processing of plastics ;
( 6 ) itself is excellent in heat resistance and chemical stability , in the processing does not decompose volatile ;
( 7 ) non-corrosive , does not pollute the film , there is no toxicity.
However, the simple use of a lubricant is often difficult to achieve the purpose , to be used in combination of several lubricants , lubricating composite developed rapidly in recent years , the inganic pigments  choice can be viewed from multiple perspectives lubricant.
Commonly used lubricants are stearic acid , butyl stearate , oleamide , ethylene bis stearic acid amide and so on .
Many substances can be used as a lubricant waxes such as natural paraffin, liquid paraffin ( mineral oil ) , microcrystalline wax , etc., but the effect is mixed. Natural wax mostly used external lubrication , the lubricant can be used as a variety of plastic , mold release agents, the general amount 0.2 ~ 1phr, but the compatibility , thermal stability and dispersibility is not good , the amount can not be too large , preferably lubricants and used ; while white oil mostly used PVC, PS internal lubricants, lubricating properties, good thermal stability , the general amount 0.5phr. they are drug-free , can be used for food packaging. Another Microcrystalline wax : in Plastics Processing is also used as a lubricant , the amount of 1 ~ 2Phr, thermal stability and lubricity better than normal paraffin .
Low molecular weight polymers are widely used heat stabilizer for foaming board  as a lubricant such as polyethylene wax, low molecular weight polypropylene , its internal and external lubrication are better, and non-toxic . PVC and polyethylene wax materials suitable for extrusion, calendering , the dosage is usually 0.1 ~ 1phr, to improve processing efficiency, prevent the film adhesion, improved dispersion of the filler or pigment , compatibility and transparency is not very good ; irregular low molecular weight polypropylene can be used as the structure rigid PVC, PE lubricant performance, can improve the dispersibility of other additives .