Inhibited Styrene Monomer

Inhibited styrene monomer contains 10-15 ppm tert-butylcatechol (TBC) as a polymerization stabilizer, maintaining stability during storage and transport. Classified under HTS 2902.50.00.00 per Chapter 29 note 2(f) allowing stabilizers necessary for preservation. Used in resin manufacturing and as copolymer feedstock.

Import Duty Rates by Country of Origin

Origin CountryMFN RateCh.99 SurchargesTotal Effective Rate
🇨🇳ChinaFree+35.0%35%
🇲🇽MexicoFree+10.0%10%
🇨🇦CanadaFree+10.0%10%
🇩🇪GermanyFree+10.0%10%
🇯🇵JapanFree+10.0%10%

Alternative Classifications

This product could be classified differently depending on its characteristics or intended use.

2914.79.40.00Lower: 13% vs 35%

If >0.5% TBC or other phenolic stabilizer

Predominant phenolic function from excess stabilizer would classify under oxygen-function compounds of heading 2914 per Chapter 29 note 4.

3824.99Lower: 15% vs 35%

If formulated as polymer initiator blend

Styrene with additives rendering it suitable for specific polymerization use classifies as chemical preparation in 3824 rather than base compound.

2902.30.00.00Same rate: 35%

If primarily toluene impurity present

Benzene/toluene dominant mixtures fall under earlier cyclic hydrocarbon headings per Chapter 29 note 3 classification rule.

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Import Tips & Compliance

Document stabilizer concentration (<50 ppm) in SDS to qualify under permitted additions of Chapter 29 note 2(f); excess may trigger mixture classification

Use nitrogen-blanketed tank containers to prevent premature polymerization during ocean transit, common cause of denied entries

Provide GC/MS analysis confirming >99% styrene content despite inhibitor presence

Related Products under HTS 2902.50.00.00

Styrene Monomer

Styrene monomer (C6H5CH=CH2) is a clear, colorless liquid cyclic hydrocarbon used primarily as a building block for polystyrene plastics and synthetic rubbers. It falls under HTS 2902.50.00.00 as a separate chemically defined cyclic hydrocarbon, specifically styrene. This unsaturated aromatic compound polymerizes readily when initiated.

Polymer-Grade Styrene

High-purity polymer-grade styrene (>99.7% purity, low aldehydes/ peroxides) specifically manufactured for polystyrene (PS) and ABS resin production. Meets HTS 2902.50.00.00 as chemically defined styrene cyclic hydrocarbon. Supplied in bulk for injection molding and extrusion applications.

Styrene for SBR Rubber Production

Styrene monomer refined for styrene-butadiene rubber (SBR) copolymerization, with strict control of impurities affecting rubber curing. HTS 2902.50.00.00 classification as pure cyclic hydrocarbon. Bulk liquid transported to tire manufacturing facilities.

Electronic-Grade Styrene Monomer

Ultra-high purity electronic-grade styrene (<1 ppm metals, <5 ppb particles) used in photoresist manufacturing for semiconductor production. Still classifies under HTS 2902.50.00.00 as chemically defined styrene despite end-use purity specs. Supplied in cleanroom-compatible containers.

Styrene with Anti-Dusting Agent

Styrene containing trace odoriferous substance (e.g., methyl acrylate) added solely for safety identification per Chapter 29 note 2(g). Remains classified HTS 2902.50.00.00 as the addition doesn't render it suitable for specific use. Used in standard polymer applications.