Polyimide Prepolymer Powder
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.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If thermoplastic polyimides that melt
Thermoplastic variants classified as fluoropolymers or specific polys in 3904 if meltable.
If cured into carbon fiber prepregs
Advanced composites with >50% fibers shift to 6815, not polymer primary form.
If as flexible polyimide films
Processed films over 0.10mm thick classified by form in 3921.90.
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Import Tips & Compliance
• 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
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