Calendering is used to produce a variety of sheet-like polymer products. In particular it is the leading method for processing vinyl.
Calendering was originally developed to process rubber, but today is widely used to make thermoplastic films, sheets, and coatings. Calendering is used most frequently in the production of vinyl products, primarily plasticized PVC (polyvinyl chloride). Calendering is popular because the thickness of the product can be set accurately and finish coatings or textures may be applied.
Calenders work by forcing a heat-softened material between two to five counter-rotating rollers that compact the sheet as it passes through. The thickness of the product film is determined by the gap between the two cylinders, called the nip region. The product sheet is then passed over cooling rollers and then may be spooled as a finished product.
(Copyright Armstrong World Industries, Lancaster, PA)
(Copyright Lubrizol Co., Wickliffe, Ohio)
One of the more common products manufactured using calendering is vinyl floor coverings, shown above on the left. Conveyer belts, shown on the right, are also produced using calendering.
- Excellent control of product thickness
- Increases the strength of material
- Allows any desired texture or pattern to be applied
- High operating cost compared to other sheeting processes
- Low tolerances cause engineering problems
- Many mechanical parts that may fail
Armstrong World Industries , Lancaster, PA
Lubrizol Co. , Wickliffe, Ohio
Chanda, Manas, and Salil K. Roy. Plastics Technology Handbook . New York: Marcel Dekker, Inc., 1998.
Wilkes, James O. , Fluid Mechanics for Chemical Engineers . Upper Saddle River, NJ: Prentice Hall PTR, 1999.