If you are importing polymers in primary forms, it's essential to know the chemical composition and what the predominant monomer is within the polymer.

For processed and finished items, it's useful to know the composition details of the polymer used and the manufacturing process. Remember that if the defining characteristic of the good is its manufacture from plastic, such as a plastic bottle or a plastic hose, it will be classified in Chapter 39 of the Tariff. If, however, the item is mentioned elsewhere in the Tariff, such as a toy made from plastic, it should be classified under the appropriate heading.

This guide provides an outline of the basic chemistry related to polymers, a simple summary of manufacturing processes and practical tips on classifying specific finished or processed goods.

Classifying polymers in primary forms

The definition of 'primary forms' is:

  • liquids and pastes, including dispersions (ie emulsions and suspensions) and solutions
  • blocks or irregular shape, lumps, powders (including moulding powders), granules, flakes and similar bulk forms

Polymers are large molecules made from monomers, and their constituent parts are called monomeric units. A monomer is a molecule or compound, usually containing carbon, which is capable of conversion to polymers, synthetic resins or elastomers by combination with itself or other similar molecules or compounds.

There are many different polymers that exhibit different characteristics and properties and are used for different purposes. For example, polyvinyl chloride (PVC) is commonly used in the building industry for use in double glazing frames. Polypropylene and polyethethylene terephthalate (PET) are commonly used in the manufacture of bottles.

To correctly classify your polymers in primary forms, you need to identify the predominant monomer:

  • polymers of ethylene (headign 3901)
  • polymers of propylene (heading 3902)
  • polymers of styrene (heading 3903)
  • polymers of vinyl chloride or other halogenated olefins (heading 3904)
  • polymers of vinyl acetate or of other vinyl esters and other vinyl polymers (heading 3905)
  • acrylic polymers (heading 3906)
  • polyacetals, other polyethers and epoxide resins, polycarbonates, alkyd resins, polyallyl esters and other polyesters (heading 3907)
  • polyamides (heading 3908)
  • amino-resins, phenolic resins and polyurethanes (heading 3909)
  • silicones (heading 3910)
  • petroleum resins, coumarone-indene resins, polyterpenes, polysulphides, polysulphones (heading 3911)

Copolymers are produced by the simultaneous polymerisation of two or more dissimilar monomers. They contain more than one type or repeat of monomeric unit. For example, the copolymer poly (ethylene co vinyl chloride) is created by polymerising an ethylene and vinyl chloride.

In Tariff classification, the term 'copolymer' covers all polymers in which no single monomer contributes 95% or more by weight to the total polymer content.

However, they are produced, copolymers - including co-polycondensates, co-polyaddition products, block copolymers and graft copolymers - are classified under the heading code covering the predominant comonomer. If no comonomer predominates, you should classify the goods in the heading code which is last in numerical order that is relevant to each of the comonomers.

Chemically modified polymers, where only appendages to the main polymer chain have been changed by chemical reaction, are classified under the heading code for the unmodified polymer.

Classifying processed or finished products

When classifying processed or finished plastic products, it's helpful to know as much about them as possible, including the:

  • function or role of the goods
  • polymer that they are made from
  • method of manufacture

The function or role of the goods is essential to classifying them correctly. The composition and method of manufacture may also be required to classify the goods correctly, although this is not always the case. However, it's a very good idea to have all this information to hand as it will speed the classification process for you.

Manufacturing techniques

Polymers in primary forms are processed using three different processes to create finished products:

  • injection moulding is used to form plastics into hollow shapes - for example, bottles and containers, toys or petrol tanks
  • compression moulding is used to form specific shapes using a mould - for example, knobs and handles for saucepans, irons or cookers or electrical fittings such as plugs, sockets and lamp fittings
  • extrusion creates shapes by forcing material through a metal forming die - for example, film, sheet, rods, profile shapes, tubes or pipes

Classifying specific types of finished or processed goods

If waste, parings and scrap (heading code 3915) have been transformed into a primary form, they should be classified as such, using the appropriate heading code between 3901 and 3914.

When classifying tubes, pipes and hoses (heading code 3917), you should bear in mind that the definition covers all hollow products, whether semi-manufactured or finished, that are used for moving gases or liquids, such as ribbed garden hoses, perforated tubes or lay-flat tubing. However, if the goods have an internal cross-section that is not round, oval, rectangular or any other regular polygon, they should be classified as profile shapes.

To classify wall or ceiling coverings made of plastic (heading code 3918), they must be wider than 54 centimetres and comprise plastics fixed permanently on a backing other than paper. The plastic layer must also be decorated, either by embossing, colouring, design-printing or graining. This is to differentiate them from some wallpapers.

There are very specific products covered under builders' ware of plastic (heading code 3925).

This heading code specifically covers:

  • reservoirs, tanks (including septic tanks), vats and similar containers, of a capacity exceeding 300 litres
  • structural elements used in floors, walls or partitions, and ceilings or roofs
  • gutters and gutter fittings
  • doors, windows and their frames, and thresholds for doors
  • balconies, balustrades, fencing, gates and similar barriers
  • shutters, blinds (including Venetian blinds) and similar articles and parts and fittings thereof
  • large-scale shelving for assembly and permanent installation, for example in shops, workshops and warehouses
  • ornamental architectural features, for example flutings, cupolas and dovecotes
  • fittings and mountings intended for permanent installation in or on doors, windows, staircases, walls or other parts of buildings - for example knobs, handles, hooks, brackets, towel rails, switch-plates and other protective plates

In some cases, textiles may be added to plastic products to provide reinforcement. If the plastic is cellular and has been covered on one face only with the textile fabric, you should classify it under the appropriate heading code in Chapter 39. If the plastic is covered on both faces, the goods should be classified as a textile, using the appropriate heading code in Chapter 59.

Common abbreviations for plastics and polymers






Butadiene-styrene block copolymer


Cellulose acetate


Cellulose butyrate


Cellulose / cellophane


Ethylene-vinyl acetate


General-purpose polystyrene


Glass-reinforced polyester


High-density polyethylene


High-impact polystyrene (toughened polystyrene)


Low-density polyethylene


Linear Low-density polyethylene


Melamine formaldehyde


Orientated polypropylene


Polyamide (nylon)

PA 6

Nylon 6

PA 6 6

Nylon 6 6

PA 4 6

Nylon 4 6

PA 6 10

Nylon 6 10

PA 11

Nylon 11

PA 12

Nylon 12


Polybutylene terephthalate






Polyethylene terephthalate