Uses of lubricants in plastics processing

The main role of lubricants is to decrease the friction between plastic materials and processing machinery as well as the friction between the molecules of plastic materials, so as to improve the processing properties of plastics and improve the performance of products.

Lubricant in the actual processing of plastics with a variety of performance. For example, it can prevent polymer adhesion to barrel, inhibit friction heat and reduce the mixing torque and load during mixing and calendering processing, thereby preventing the thermal degradation of polymeric materials. At the time of extrusion, it can increase liquidity, improve the adhesion of polymer materials with the barrel and mold, prevent and reduce retention.

Lubricants according to chemical structure can be divided into amides of fatty acids, hydrocarbons, fatty acids, esters, alcohols,

In the processing of plastics industry, according to the different interfaces between material and material, it can be divided into external lubricant and internal lubricant. Inner lubricant has a certain affinity with polymer, metal soaps and compound lubricants; but according to use, it can be divided into inner lubricant (such as fatty alcohols, fatty acids, etc) and external lubricants (such as fatty and fatty amides, paraffin etc) and composite lubricant (such as metal SOAP calcium stearate, fatty acid soaps and fatty amides, etc).

The use of lubricants generally is 0.5%~1%, its selection should be noted as follows:

1 When the flow properties of polymer has meet forming process needs, the main consideration is the role of outer lubrication to guarantee both inside and outside balance.

2 Whether external lubrication is effective or not, the criteria is whether it can form a complete liquid films on plastic surface at forming temperature. Therfore, outer lubricants melting point should be close to molding temperature,  but a difference of 10℃~30℃ can form a complete film.

3 Do not reduce the mechanical strength and other physical properties of the polymer.

The most commonly used lubricants include stearic acid, butyl stearate, oleamide, formamide, ethylene bis stearamide, etc. OKCHEM also has lead stearate, plastic talc powder, calcium stearate, oleic acid (high-pure), barium stearate and so on. If you have interest in lubricants and other plastic raw materials, please click here for more!

Source: https://www.okchem.com/news/uses-lubricants-plastics-processing.html