Standard International Trade Classification
U.S. imports of Natural Polymers & Modified Natural Polymers N.E.S. in Primary Forms (SITC 57595) totaled $32.4M in August 2026, imported from 44 countries.
Importers of Natural Polymers & Modified Natural Polymers N.E.S. in Primary Forms paid $4.2M in duties in August 2026, an average duty rate of 12.88% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule.
Last updated: August 2026 dataHardened proteins (such as casein plastics and zein), chemically modified natural rubber derivatives, and other biopolymers not classifiable under more specific headings constitute this residual category of natural and semi-synthetic polymers. Dextran, guar derivatives beyond standard gum grades, and chemically modified starches that have crossed into polymer territory may also appear here depending on their degree of modification. The NES designation makes precise documentation of chemical identity and processing history essential, as customs authorities may challenge classification if a product appears to belong under a more specific heading for proteins, rubber, or starch. This category intersects with bio-based materials innovation, where novel feedstocks are increasingly entering trade.
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901 import shipments a month
Importers should supply a detailed technical data sheet identifying the base natural material (protein, rubber, polysaccharide, etc.), the specific chemical modification applied, and the resulting polymer properties. A statement confirming the product is not more specifically classifiable under headings for natural rubber, proteins, or starches strengthens the classification position. A CBP binding ruling is advisable for novel or high-value materials.
No. Raw natural rubber is classified and regulated separately. Chemically modified rubber derivatives that have been transformed into polymer form — such as chlorinated rubber or cyclized rubber — are classified as chemical products rather than raw rubber, and do not carry the same phytosanitary or commodity-specific requirements. However, importers should confirm the degree of modification is sufficient to support the polymer classification.
Basic heading 127 of 465 in section 5
Basic heading 57595 · $32.4M of $27.5B
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Imports · August 2026
origin
Sweden and China together supply 47% of it. China pays 42.5% duty; Sweden 3.4%.
customs district
Census does not publish district detail for this classification system.
destination
Census does not publish state detail for this classification system.
entry
Census does not publish port detail for this classification system.
ImportsExports
Imports
$32.4MYoY · free account
Exports
$28.1MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $374.1M of Natural Polymers & Modified Natural Polymers N.E.S. in Primary Forms and exported $326.8M.
Through August 2026. Source: U.S. Census Bureau.