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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 $3.2M in April 2026, traded with 5 countries.
Importers of Mixtures of Oligomers of TMQ (2,2,4-Trimethyl-1,2-Dihydroquinoline) paid $678K in duties in April 2026 — an effective duty rate of 21% on $3.2M 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 $3.2M in April 2026 ran 33% above the year-to-date monthly average of $2.4M.
Last updated: April 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.
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.
Monthly import values over time
HS10 import codes under this HS6 parent. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Duty Collected |
|---|---|---|---|---|
| 3812310000 | COMPND PLASTZRS FOR RUB/PLAST, TRIMETHYL/DIHYDROQN | $3.2M | 21.48% | $678K |
COMPND PLASTZRS FOR RUB/PLAST, TRIMETHYL/DIHYDROQN
HS10 export codes under this HS6 parent. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 3812310000 | COMPND PLASTZRS FOR RUB/PLAST, TRIMETHYL/DIHYDROQN | $575K |
COMPND PLASTZRS FOR RUB/PLAST, TRIMETHYL/DIHYDROQN
131.0K kg
PRODUCTS AND RESIDUALS OF CHEMICAL INDUSTRY, NESOI
HS 382499
DIAGNOSTIC OR LABORATORY REAGENTS INCL KITS, NESOI
HS 382219
CHEM ELEM DOPED, USED IN ELECTRON, DISCS WAFERS ET
HS 381800
SUPPORTED CATALYSTS W PREC METAL/PREC MTL COMPND
HS 381512
SUPPORTED CATALYSTS, NESOI
HS 381519
ADDITIVE FOR LUB OIL CONT PETRO/BITUMINOUS MINOIL
HS 381121
Supplier Network
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| State | Imports | Exports | Balance |
|---|---|---|---|
| South Carolina | $2.5M | $248K | -$2.3M |
| Ohio | $261K | $194K | -$67K |
| Michigan | $82K | $66K | -$16K |
| Port | Imports | Exports | Balance |
|---|---|---|---|
| CHARLESTON, SC | $2.5M | $25K | -$2.5M |
| SAVANNAH, GA | $205K | -- | -$205K |
| NEW YORK, NY | -- | $198K | +$198K |