Chemical Engineering - Polymer Technology - Discussion

Calendering is a speciality process for high-volume, high quality plastic film and sheet, mainly used for PVC as well as for certain other modified thermoplastics. The melted polymer is subject to heat and pressure in an extruder and formed into sheet or film by calendering rolls.

Mastication, the process by which the viscosity of natural rubber is reduced to a suitable level, is an important step in the mixing process. Rubber polymers such as Natural Rubber (NR) require mastication to reduce their viscosity/elasticity and to even out variations between different polymer lots.

Plastics extrusion is a normally high volume manufacturing process where a polymer material, enriched with the desired additives, is melted and formed in a continuous process. The raw material (polymer) in the form of granulates, is gravity fed into the hopper and through the feed throat, drops on a rotating screw.