HS Code for PIB

Polyisobutylene (PIB) is classified under HS code 3902.20, which falls under the category of polymers of propylene or other olefins in primary forms. Chapter 39 of the Harmonized System deals with plastics and articles thereof, and heading 3902 is dedicated to polymers of propylene or other olefins. Subheading 3902.20 specifically identifies polyisobutylene. The classification is determined by the chemical structure of the polymer, which is a synthetic rubber or semi-solid viscous polymer. For the purposes of this classification, "primary forms" are defined in Note 6 to Chapter 39 as liquids and pastes, including dispersions (emulsions and suspensions) and solutions, or blocks of irregular shape, lumps, powders, granules, flakes, and similar bulk forms. PIB is valued for its impermeability to gases and its flexibility. It is used extensively in the manufacture of inner tubes, adhesives, and as a viscosity modifier in lubricant oils. The classification process involves verifying that the substance is a polymer where isobutylene monomer units predominate by weight over any other single comonomer unit, in accordance with the polymer notes in Chapter 39. If the product is mixed with other substances, such as solvents or additives, it must still retain the character of a polymer in primary form to remain under this code.

Products Included

• Low molecular weight polyisobutylene in liquid form
• High molecular weight PIB in solid blocks
• Polyisobutylene granules for industrial use
• PIB dispersions used in adhesive manufacturing

Common Misclassification

PIB is frequently misclassified under 3901.10 or 3901.20 (Polyethylene) due to its similar appearance in pellet form. It may also be confused with 4002.31 (Butyl rubber), which is a copolymer of isobutylene and isoprene; pure PIB must be classified in Chapter 39, while the copolymer is classified in Chapter 40. Additionally, if PIB is heavily diluted in mineral oil (less than 50% polymer), it might be misclassified under 2710.19 as a lubricant additive.

FAQ

What is the HS code for PIB?

The HS code for Polyisobutylene in primary forms is 3902.20.

Is PIB classified as a plastic or a rubber?

In the Harmonized System, pure polyisobutylene is classified as a plastic under Chapter 39 (3902.20), whereas its copolymer, butyl rubber, is classified as synthetic rubber under Chapter 40.