Other

39.11 - Petroleum resins, coumarone-indene resins, polyterpenes, polysulphides, polysulphones and other products specified in Note 3 to this Chapter, not elsewhere specified ox included, in primary forms. 3911.10 - Petroleum resins, cownarone, indene or coumarone-indene resins and polyterpenes 3911.90 - Other This heading covers the following products : (I) Petroleum resins, coumarone, indene or coumarone-indene resins and polyterpenes constitute a group of resins, not highly polymerised, made b polymerising more or less impure fiacbons obtained, respectively, from deeply cracke petroleum distillates, from coal tar or from turpentine or other sources of terpenes. They are used in adhesives and coatings and are often incorporated as softeners in rubber or plastics, for example, for use in floor tiles. 7' (2) Polysulphides are polymers characterised by the presence of rnonosulphide linka es in the polymer chain, for example, poly(pheny1ene sulphide). In polysulphides each sulp ur atom is bound on both sides by carbon atoms, as opposed to the thioplasts of Chapter 40, which contain sulphur-sulphur linkages. Polysul hides are used in coatings and in moulded articles, for example, aircraft and automobi e parts, pump impellers. % P (3) Polysulphones are polymers characterised by the presence of sulphone linkages in the olymer chain, for exam le, the roduct obtained b reacting the sodium salt of gisphenol A (4,4'-isopropy idene-dip enol) with bis (4-c lomphenyl) sulphone. They are used in electncal parts, domestic appliances, etc. 'f K E (4) Polymers with isocyanate groups, not elsewhere specified or included, such as (a) Polyureas based on hexamethylene diisocyanate (HDI), synthesised by the reaction of HDI with water to roduce prepolymers with an average number of monomer units of between 3 and 4. &e products are used in the manufacture of paints and varnishes. (b) Polyisocyanurates based on hexamethylene diisocyanate (HDI), synthesised by the reaction of HDI to produce prepolymers with isocyanurate links between monomer units. The prepolymers have an average number of monomer units of between 3 and 5. The products are used in the manufacture of paints and varnishes. (5) Other roducts s ecified in Note 3 to the Chapter include polyxylene resins, poly (1,tdiisopropy benzene), polyvinyl ketones, polyethyleneimines and polyimides. P For the classification of olyrners (includin copolymers , chemically modified polymers and polymer blends, see the eneral Explanatory ote to this hapter. k A