Polyisobutylene

39.02 Polymers of propylene or of other olefms, in primary forms. 3902.10 - Polypropylene - Polyisobutylene 3902.30 - Propylene copolymers 3902.90 - Other 3902.20 of all olefins (i.e. acyclic h drocarbons having one or more The important polymers o this heading are polyprop lene, copolymers. For the classification of polymers (inc uding polymers and polymer blends, see the General Explanatory ? r The eneral physical properties of polypropylene are polyetk,ylene. Polypropylene and propylene cop01 ers applications, for example, packaging film, mo ded housewares, etc., wire and cable coating, food container products, bottles, ha s and containers for storing precision equipment, ducting, tank linings, piping for chemical p ant, tufted carpet backing. z" K Polyisobutylene when suMicient1 olymerised resembles rubber but is not classified in Chapter 40 as it does not conform to the e inition of synthetic rubber. It is used for waterproof coatings and for modifying other plastics. Ji! Polyisobutylene, slightly polymerised and meeting the requirements of Note 3 (a) to this Chapter, is also included in this heading. It is a viscous liquid used to modify the properties of lubricating oils. The heading, however, does not cover liquid s thetic polyisobutylene or other liquid synthetic polyolefins not meeting the requirements of Note 3 to this Chapter (heading 27.10).