HS 3506.91 vs 3506.10 vs 3208 for Loudspeaker Adhesives

Two pallets leave the same Dongguan supplier on one booking. One holds twelve 20 kg pails of waterborne surround adhesive; the other, 3,000 blister-packed 20 g cyanoacrylate bottles. Your broker, reading an invoice that says "adhesive" twice, puts both on one line. The correct answer is at least two subheadings and possibly three headings — a difference that decides duty rate, which trade-remedy programmes touch the entry, and how defensible the declaration looks if anyone reads it closely.

HS 3506.91 is where most industrial loudspeaker adhesives land. But 3506.10 pulls small retail packs out from underneath it regardless of chemistry, and heading 3208 pulls certain solvent-borne grades out of Chapter 35 entirely. Below: the legal test for each, the products that sit on the wrong side of it, and the data you need from the supplier.

Everything here is a reasoned candidate, not a ruling. Classification is done per product, on the product as presented, by the authority of the country of import. Confirm each before you enter goods against it.

Where heading 3506 sits, and what it does not cover

Heading 35.06 reads: Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg.

First, "not elsewhere specified or included" makes 3506 residual: an adhesive specified in another heading goes there instead. Within Chapter 35 alone that removes starch and dextrin glues (3505.20), casein glues (3501.90) and gelatin glues (3503). None is speaker work, but the principle matters — the same residual logic is what sends certain solvent-borne adhesives to Chapter 32.

Second, the semicolon splits the heading in two. The first limb covers prepared adhesives generally; the second covers a defined presentation — retail put-up, 1 kg or less — and is chemistry-blind. The subheadings follow the same split:

• 3506.10 — products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg
• 3506.91 — other: adhesives based on polymers of headings 39.01 to 39.13 or on rubber
• 3506.99 — other: other

Because 3506.10 is the first one-dash subheading, you test it before you get near 91 or 99. Get that order wrong and you classify a retail pack by its chemistry — the most common error in this heading.

The two tests that pull goods out of 3506.91

The 3506.10 test: retail put-up, and 1 kg net

The 3506.10 conditions are cumulative. Both must be met.

Condition one: put up for retail sale as glues or adhesives. This is about presentation, not about who the buyer is. The clear case is a 20 g bottle on a printed blister card, barcoded, ready to hang on a rack. The hard case is the 500 g industrial bottle with a printed label, shipped 24 to a case to a factory. One reading holds the packing form itself satisfies "put up for retail sale" — a consumer-scale unit ready for sale without repacking; the competing reading holds that goods invoiced in trade quantities to an industrial user are not put up for retail sale at all. Authorities have not been consistent, which is why the format is worth a ruling if you ship it repeatedly.

Condition two: net weight not exceeding 1 kg. Three details decide it:

• Net, not gross. The weight of the adhesive itself, excluding the bottle, the card and the carton.
• Per individual retail package, not per shipment or per outer carton. A master carton holding fifty 20 g bottles weighs a kilogram of adhesive; each package is 20 g, and it is the package that is tested.
• Two-part kits are genuinely open. If a retail blister holds 25 g of resin and 25 g of hardener, is the test the 50 g combined put-up or each component? The natural reading is the put-up as presented, and 50 g clears either way — but scale it to a 600 g + 600 g pack and the question decides the subheading. Get a ruling before importing that format.

The practical consequence: the same adhesive, in two pack sizes, is two different subheadings. A cyanoacrylate in a 20 g retail bottle and the identical product in a 500 g industrial bottle do not share a code, may not share a duty rate, and are not covered by the same ruling. Private-label programmes trip over this constantly — the decision to sell in small packs is made by marketing, the consequence found by the broker.

The 3208 argument: when an adhesive is legally a "solution"

This is the least-known boundary here, and the one most likely to be sitting wrong on an existing entry.

Note 4 to Chapter 32 defines, for the purposes of heading 32.08, the expression solutions as meaning — except in the case of collodions — solutions of the products specified in headings 39.01 to 39.13 in volatile organic solvents when the weight of the solvent exceeds 50% of the weight of the solution. Heading 32.08 then covers, alongside paints and varnishes in a non-aqueous medium, "solutions as defined in Note 4 to this Chapter". Chapter 39 carries the mirror exclusion: those solutions are out of Chapter 39 and in 32.08.

The argument runs like this. A solvent-borne adhesive whose binder is a polymer of headings 39.01 to 39.13 — an acrylic (39.06), a vinyl acetate polymer (39.05), a polyurethane (39.09), an epoxide resin (39.07) — and in which volatile organic solvent exceeds 50% by weight meets the Note 4 definition, and is therefore specified in heading 32.08. Because 35.06 applies only to prepared adhesives not elsewhere specified or included, the goods leave Chapter 35 and are declared in 32.08 — most often 3208.20 for acrylic or vinyl polymers, 3208.90 for others.

Three counter-arguments carve out most of what a speaker-adhesive house actually sells:

1. Rubber-based systems are outside Note 4 entirely. Note 4 is limited to products of headings 39.01 to 39.13. Rubber is not among them. A solvent-borne contact adhesive based on polychloroprene or another elastomer therefore cannot become a Note 4 solution however much solvent it carries, and stays in 3506.91, which explicitly covers adhesives based on rubber.
2. Water-based grades cannot reach 3208 by this route. Note 4 requires volatile organic solvents. Water is not one. A waterborne foam-and-rubber surround adhesive is outside the argument by definition — which removes one of the highest-volume grades in a driver bond schedule from the question altogether.
3. A compounded, filled adhesive may not be a "solution" at all. Note 4 speaks of solutions of a polymer in a solvent; a product carrying tackifiers, fillers, pigments and additives is arguably a prepared mixture, and stays in 3506. This is the argument most often run successfully and the one most dependent on the exact formulation — which is why it needs a ruling rather than a view.

One boundary sits nearby: an unvulcanised compounded rubber solution or dispersion not prepared and put up as an adhesive can fall to 4005.20 rather than 3506. Preparation as an adhesive is the dividing line.

The candidate matrix

Read this as arguments with their decisive facts attached, not as a code list to copy onto an invoice.

The cyanoacrylate question, set out properly. A cyanoacrylate is supplied as a monomer — an ester of cyanoacrylic acid — that polymerises in the joint on contact with surface moisture. Read strictly, the product as presented is not "based on polymers of headings 39.01 to 39.13 or on rubber", because at importation there is no such polymer in the bottle; that reading puts bulk cyanoacrylate in the residual 3506.99. The counter-argument is that the cured adhesive is a poly(cyanoacrylate), an acrylic polymer of heading 39.06, and that "based on" describes the chemistry of the system rather than its state in the container. Both are arguable and national practice is not uniform. If you import bulk cyanoacrylate regularly, this is the line in your tariff file most worth a ruling.

Getting to an answer you can defend

What only the supplier can tell you

Most of the matrix turns on facts only the manufacturer holds. Ask, per grade, in writing:

1. The base polymer family, named — acrylic, vinyl acetate, polyurethane, epoxide, polychloroprene or other rubber, cyanoacrylate monomer.

2. Water and organic solvent content as a percentage by weight of the product as supplied. Note 4's 50% line is a weight-of-solution test, so an approximation is not enough near the threshold.

3. Whether the product is a polymer solution or a compounded mixture carrying fillers, tackifiers and additives, and what proportion is non-binder solids.
4. Net weight per individual container, and the container format.
5. Whether any grade is packed and labelled for retail sale, private-label programmes included.
6. For two-part systems, whether A and B ship packed together or as separate line items — separated components can classify differently from the kit, and a hardener shipped alone is not necessarily an adhesive.
7. The six-digit subheading on the export documentation. The first six digits are common to all HS members, so a mismatch there is worth chasing before the goods sail; below six digits the codes are national and yours governs your entry.

Items 1 to 3 already sit in a document you need anyway. The safety data sheet's composition section gives the binder and solvent identities; its physical-properties section gives flash point, which tells you at once whether the product is solvent-borne. Ask for the SDS in the same message as the UN number, proper shipping name, class and packing group, and most of your classification evidence arrives as a by-product of the dangerous-goods work. The same enquiry discipline that gets you a usable quote — send both substrates and the cure window — collects these fields too.

One warning specific to this category: a quantity stated in "units" is not a quantity, and a code cannot be built on it. A listing quoting a minimum of 1,000 units without saying whether a unit is a bottle, a cartridge, a syringe or a kilogram — as the Aosibo Adhesives listing on CMH explicitly does — is normal for this trade. But net weight per container decides 3506.10, so pin the unit of measure down first.

The rulings that bind

For a programme you will repeat, a ruling is cheap next to one held container.

United States. A binding ruling from CBP, requested through the eRulings portal to the National Commodity Specialist Division, with a full description, the composition, the pack format and, where useful, a sample. Search the CROSS database first — adhesives are heavily ruled territory and a materially identical product may already have an answer.

European Union. Binding Tariff Information, applied for through the EU Customs Trader Portal, binds the customs authorities of all member states and the holder for three years — which matters if you enter through more than one port. The United Kingdom runs its own advance tariff ruling process separately.

Both are free of official charge. Stated target markets for this kind of range routinely span both — the Aosibo listing names the United States, Canada, the United Kingdom, Germany, France, the Netherlands, Indonesia and the UAE — and a programme shipping into two or three of them wants a ruling in each major market rather than one view carried across borders.

Common questions

The duty rate looks the same either way. Does the code still matter?

Yes. Penalty exposure for a material misstatement does not depend on revenue loss, trade-remedy programmes and preferential-origin rules are written to codes rather than to rates, and a held container costs demurrage regardless of what it would have paid in duty. Work the landed-cost model from the correct code, not the convenient one.

My supplier gave me a code. Can I just use it?

Use it as an input, not as an answer. Classification for import is the importer's duty of reasonable care, and it does not transfer to the seller or to the broker acting on your invoice. If that division of responsibility is not clear in your operation, start with what an importer of record actually carries.

We reformulated to a lower-solvent version. Does the code change?

It can, and that is the trap in the 3208 argument. Note 4 is applied to the product as presented, so a change crossing the 50% solvent line moves the goods between chapters without altering the product name, the part number or anything on your purchase order. Put a change-notification clause covering solvent system and base polymer in the contract, and re-check the classification when it fires.

What to put in the file before you enter

1. A one-page composition summary per grade: base polymer family, solvent identity and weight percentage, water percentage, solids and filler content.
2. The safety data sheet for that exact grade, with the composition and flash-point sections legible.
3. Net weight per individual container, plus a photograph of the pack as presented including any retail card or label.
4. For two-part systems, whether components ship together or separately, and the weight of each.
5. Your classification reasoning written out — heading first, then subheading, with the Note 4 test answered yes or no.
6. The supplier's six-digit export subheading, for comparison.
7. Ruling requests filed for any grade you import more than once, especially bulk cyanoacrylate and any solvent-borne grade near the 50% line.

Aosibo Adhesives illustrates why this file is per grade rather than per supplier. Its published range spans a waterborne foam-and-rubber surround adhesive, lead-wire, damper and magnet-circuit adhesives, a centring adhesive in one-part, epoxy and halogen-free versions, and two-part epoxy and acrylic AB systems and cyanoacrylates — which on a strict reading can straddle 3506.91, 3506.99, potentially 3506.10 in a retail format, and heading 3208 if any grade is a high-solvent polymer solution. That is three subheadings and two chapters from one supplier's catalogue. Sending a per-grade composition and pack-format table with your first order, and classifying line by line off it, is the cheapest customs control an adhesive importer has. The code is also what connects a drum of glue to everything else in the entry, so settle it alongside the wider question of how duty and tariff programmes apply to China-origin goods.