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HSChapter 38
U.S. imports of mixtures of oligomers of tmq (2,2,4-trimethyl-1,2-dihydroquinoline) (HS 381231) totaled $3.8M in July 2026, traded with 5 countries.
Importers of Mixtures of Oligomers of TMQ (2,2,4-Trimethyl-1,2-Dihydroquinoline) paid $671K in duties in July 2026 — an effective duty rate of 19% on $3.5M in dutiable value, based on actual customs collections rather than the published tariff schedule. Mixtures of Oligomers of TMQ (2,2,4-Trimethyl-1,2-Dihydroquinoline) imports of $3.8M in July 2026 ran 30% above the year-to-date monthly average of $2.9M.
Last updated: July 2026 dataTMQ — a quinoline-derived antidegradant widely used to protect natural and synthetic rubber from heat aging and oxidation — is classified under a single 10-digit line (3812310000) within the antidegradant subheading of Chapter 38. Germany and Italy lead US import supply, with China and India also significant sources, reflecting both European specialty chemical production and Asian cost-competitive manufacturing. Imports of TMQ from China are subject to Section 301 tariffs, a factor that has increased attention to European and Indian supply as alternatives for tire and industrial rubber goods producers.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
89 shipments/mo
TMQ acts as an antidegradant — specifically an antioxidant — that inhibits the thermal and oxidative degradation of rubber during both processing and service life. It is widely used in tire sidewalls, conveyor belts, and other rubber goods exposed to elevated temperatures. The oligomeric mixture form provides a balance of volatility, solubility, and antidegradant efficiency compared to the pure monomer.
If TMQ oligomers are the primary or essential-character component of the blend, classification under 3812310000 is generally appropriate. However, if the blend contains substantial proportions of other antidegradant types — such as phenylenediamine-based antiozonants — the classification may shift to a different subheading based on the dominant component. A binding ruling from CBP is advisable for complex antidegradant packages where the essential character is not clear-cut.
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ImportsExports
Imports
$3.8MYoY · Pro
Exports
$487KYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 3812310000 | Compnd Plastzrs for Rub/Plast, Trimethyl/Dihydroqn | $3.8M | 17.88% | 93.41% | $671K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 3812310000 | Compnd Plastzrs for Rub/Plast, Trimethyl/Dihydroqn | $487K |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
Imports · July 2026
origin
Germany and China together supply 91% of it.
customs district
destination
entry
rate provision · imports
the effective duty rate is 17.88%.