Division 4 For the purposes of this chapter, except where the context otherwise requires, copolymers (including co-polycondensates, co-polyaddition products, block copolymers and graft copolymers) and polymer blends are to be classified in the heading covering polymers of that comonomer which predominates by weight over every other single comonomer, comonomers whose polymers fall within the same heading being regarded as constituting a single comonomer.
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If no single comonomer predominates, copolymers or polymer blends, as the case may be, are to be classified in the heading which occurs last in numerical order among those which equally merit consideration.
The expression ‘copolymers’ covers all polymers in which no single monomer contributes 95 % or more by weight to the total polymer content.