Polyimide Prepolymer Powder from Mexico
Thermosetting polyimide prepolymer powder in primary form for aerospace composites. Under 3911.90.91.50 as NES thermosetting product, classified by predominant imide monomer units.
Duty Rate — Mexico → United States
16.5%
Rate breakdown
9903.05.5510%Section 301 (forced labor) — additional 10% ad valorem on products of Mexico
Import Tips
• Include cure cycle instructions proving thermoset transformation from prepolymer state
• Test for 95% imide content to rule out copolymer shifts per subheading note (a)(2)
• Comply with ITAR if for defense applications; separate from tariff classification