Cyclized Rubber (Alkylated Chlorosulfonated Rubber)
Cyclized rubber is produced by treating natural rubber with sulfuric acid or other agents to create cyclic structures, yielding a harder derivative used in paints and varnishes. It appears in primary flake or powder form. Falls under HTS 3913.90.1000 as a chemical derivative of natural rubber not elsewhere specified.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If petroleum sulfonates predominate
Specific chemical derivatives of natural polymers have dedicated subheadings in 3911 taking precedence.
If waste or scrap processed form
Processed natural rubber waste/scrap, even chemically treated, falls under 4004 regardless of primary form.
If pre-mixed into paint/varnish base
If beyond primary form and incorporated into paints, classifies under Chapter 32 as prepared pigment.
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Import Tips & Compliance
• Submit chemical structure analysis proving cyclization of natural rubber polyisoprene to confirm 3913 classification
• Label clearly as 'primary form' to distinguish from finished articles in Chapter 40 or 39 headings
• Watch for misclassification as reclaimed rubber (4003) if processing involves devulcanization
Related Products under HTS 3913.90.10.00
Chloroprene Rubber (CR)
Chloroprene rubber, a synthetic elastomer produced by polymerization of chloroprene (2-chloro-1,3-butadiene), is a chemical derivative of natural rubber isoprene structure. It is supplied in primary forms such as bales or pellets for use in manufacturing weather-resistant products like wetsuits and hoses. Classified under HTS 3913.90.1000 as it qualifies as a chemical derivative of natural rubber per chapter notes on polymers.
Hydroxyl-Terminated Polyisoprene (HTPI)
HTPI is a telechelic natural rubber derivative with hydroxyl end-groups, used as a reactive prepolymer in polyurethane elastomers and adhesives. Supplied as viscous liquid or solid in drums. HTS 3913.90.1000 covers this chemically modified natural rubber in primary form.
Epoxidized Natural Rubber (ENR)
ENR results from partial epoxidation of natural rubber's double bonds, improving oil resistance for tire compounds and adhesives. Available in latex or solid bale primary forms. Chemical modification places it definitively under HTS 3913.90.1000.
Gutta-Percha Resin
Gutta-percha, a trans-1,4-polyisoprene from Palaquium trees, is chemically similar to natural rubber but more rigid; used in golf balls and dental applications. Processed into primary resin pellets. As a natural polymer chemical derivative, it fits HTS 3913.90.1000.
Maleated Natural Rubber (MNR)
MNR features maleic anhydride grafted onto natural rubber backbone for better adhesion in rubber composites. Supplied as primary crumb or powder. Grafting qualifies it as chemical derivative under HTS 3913.90.1000.
Liquid Polyisoprene Rubber (LIR)
LIR-3000/700 series are low molecular weight liquid derivatives of natural cis-1,4-polyisoprene, used as reactive plasticizers in tires and sealants. Primary liquid form in drums. Chemical degradation/polymerization modification places under HTS 3913.90.1000.