# PU sealant HS code: 3214.10 or 3506.90?

> How PU sealant is classified: 3214.10 as a mastic or 3506.90 as an adhesive, the duty difference, and the four documents customs asks for on entry.

Updated: 2026-11-12 · Source: https://karmindadhesive.com/resources/pu-sealant-hs-code/

Two headings decide what a polyurethane sealant costs at the border: 3214.10 (mastics) and 3506 (prepared glues and adhesives). The difference is not academic. In the EU the third-country rate for 3214 10 10 is 5% and for 3506 91 10 it is 6.5%; in the US, a PU windscreen adhesive was classified in 3214.10.0020 at 3.7%. On a €30,000 shipment that is a few hundred euros — and a misclassification that surfaces in an audit costs more than the duty.

## The two headings that matter

| Heading | What it covers | Typical rate |
|---|---|---|
| **3214.10** | Glaziers' putty, resin cements, caulking compounds and other mastics | EU 5% (3214 10 10); US 3.7% (3214.10.0020) |
| **3506.91 / 3506.90** | Prepared glues and adhesives, including adhesive sealants put up for retail sale | EU 6.5% (3506 91 10) |

The words in the tariff are old, but the distinction is functional: 3214 covers products used to fill and seal joints; 3506 covers products used to bond surfaces. A one-component PU sealant that is gunned into a joint and cures in place is a mastic, even if its data sheet calls it an adhesive.

## Why a sealant is not a glue, for customs purposes

The Explanatory Notes to 3506 exclude products having the character of mastics of 32.14. That is why a PU windscreen adhesive — a product whose primary job is to hold glass and seal water out — was classified in 3214 by US Customs rather than in 3506, despite the broker's original suggestion.

The practical test is a sentence: *if the product is applied as a bead into a gap and its job is to keep something out or fill the gap, it is a mastic; if it is applied as a film between two surfaces and its job is to carry load, it is an adhesive.* Many products do both, which is exactly why the declaration needs the application, not just the chemistry.

## What customs asks for, in order

| Document | What it must show |
|---|---|
| Commercial invoice | Product name, model, quantity, unit value, Incoterm, origin |
| Packing list | Cartons, pallets, net and gross weight, pack format |
| Technical data sheet | Chemistry (one- or two-component PU), use, application method |
| Safety data sheet | Hazard classification, flash point, transport UN number if dangerous |
| Composition statement | Polymer type, filler load, solvent content, in percentages |

A classification that cannot be tied to those five documents is a guess. The SDS matters twice: it drives the HS question (solvent-borne products can classify elsewhere) and the transport question (some PU grades are not dangerous goods, some are).

## Worked example: one pallet of cartridges

A 20 ft container of 310 ml cartridges, 12,800 pieces at 400 g each, is about 5.1 t of product. At a CIF value of €18,000:

- classified in 3214 10 10 at 5% → **€900 duty**
- classified in 3506 91 10 at 6.5% → **€1,170 duty**

The difference is €270 on one container. Where the code is wrong, the cost is not only the duty: an audit can reopen past entries, and the importer carries the penalty, not the factory.

## Where classification goes wrong

- **Declaring 3506 because the product is called an adhesive.** The name on the label does not decide; the function does.
- **Declaring 3214 for a structural adhesive.** A crash-rated panel bond is not a mastic, and describing it as one misstates the product to customs and to the customer.
- **Ignoring the solvent.** Solvent-borne products may fall outside both headings; the SDS is the document that tells you.
- **Assuming the factory's code travels.** The exporter's declaration is a starting point. The importer's broker is the party that signs.

## What this means for buyers

Ask the supplier for the composition statement and the SDS before the first shipment, and give your broker the application in one sentence — "gunned into a concrete joint to seal water out" or "bonded between panel and frame to carry load". The code follows from that sentence. If a supplier cannot say which heading their product falls under, that is a signal about the paperwork you will receive for the next five years.

## Sources

- EU tariff, heading 3214 and 3506: https://hscode.info/en/hs-code/sealant
- EU TARIC consultation: https://ec.europa.eu/taxation_customs/dds2/taric/taric_consultation.jsp?Lang=en
- US Customs ruling NY N324403 (PU windscreen adhesive, 3214.10.0020): https://www.customsmobile.com/rulings/docview?doc_id=NY+N324403
- US HTS current edition: https://hts.usitc.gov/current