Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms
Alginic acid, its salts and esters, in primary forms
Natural polymers and modified natural polymers, e.g. hardened proteins, chemical derivatives of natural rubber, n.e.s., in primary forms (excl. alginic acid and its salts and esters)