Blow moulding occurs when molten plastic in the shape of a tube is expanded within a split mould of the shape of the finished product. Blown film is a variation of the extrusion process that continuously expands a tube of molten plastic into a thin bubble that is cooled in air to produce thin film, typically used for packaging and bags. C Glossary Index Catalyst is a substance that increases the rate of a chemical reaction. Calendering is an alternative to the extrusion method of making sheet materials such as vinyl flooring. Their use is being phased out because their emission into the atmosphere has been found to deplete the ozone layer.
Chlorine is derived from salt, and used to make vinyls.
Compression moulding is a simple process of compressing plastic into a hot cavity mould, which is then cooled, for thermoplastics. No cooling is needed for thermoset plastics. Copolymer is the polymer resulting from the use of two or more different monomers during polymerisation. Cracking is the process of separating crude oil into its chemical components by boiling and distilling. Cradle to grave studies assess the life cycle of a product from raw material, manufacture, use and waste disposal.