Wallpaper glue powder manufacturer in China: how to shortlist one

Shortlist a wallpaper glue powder manufacturer in China on things you can verify without a purchase order: a named model with its starch base and published viscosity including test conditions, a fixed packing format, a document set that matches that model, and a sample record you can repeat on the bulk batch. Everything else, including price and lead time, is a conversation that only becomes useful after the model passes your own trial.

Request the model TDSRead the company facts

A manufacturer answers with a model, not a catalogue

  • Wallpaper adhesive powder is a category name, not a product. Ordinary grades, universal grades, anti-mold grades and base powders sold for repacking behave differently in the bucket, dry at different rates and hold seams differently on the same wall. When a first reply lists dozens of codes with no test conditions, you are comparing brochures. When it names one or two models, states the starch base and gives the viscosity with the method behind it, you can start a technical conversation.
  • Ask for the model name as it would appear on a purchase order and on the bag. A code that only exists in a chat message is a code that will not survive the first quality discussion, because nobody can prove which powder was actually shipped.
  • Model identity: name, grade and starch base. KARN lists K6 (ordinary grade, tapioca modified starch), 999 (universal grade, main export model, potato modified starch), 999+ (anti-mold grade, potato modified starch) and KN-999, a base powder supplied for repacking.
  • Published viscosity with its method: concentration, instrument, rotor and speed. K6 is published at 38,000 ±10% mPa·s on a 5% solution, NDJ-8, No. 4 rotor, 6 rpm; 999, 999+ and KN-999 carry their figure in the model TDS.
  • Packing as a fixed format rather than a photo: 20kg net in a kraft paper bag with a PE liner, with pallet, loading, marks and labels confirmed per order.
  • Documents by model: TDS and the pre-shipment QC standard per model, MSDS applicability by model and market, and a batch COA only when one was issued for that batch.
  • The repacking answer, if you intend to sell under your own brand: 200g, 300g, 500g or 1kg packs, with artwork, barcode and label language agreed before production.
  • A straight answer about what the supplier does not do: no warehouse in your market, no local importer role, no third-party approval attached to a model unless a current document exists.

The four documents, and the question each one answers

  • Buyers routinely receive four documents and treat them as interchangeable. They are not. A TDS describes a model. A batch COA describes one identified batch. An MSDS describes handling, storage and transport. The pre-shipment QC standard describes what the factory checks before loading. None of them tells you whether the powder suits your wallpaper, your water or your wall, and none of them is a certificate.
  • Read the viscosity line first, because it is where the difference between a real sheet and a decorated one shows. A number without concentration, instrument, rotor and speed cannot be compared with anything, including the same supplier’s second model. If the sheet gives a range with no method, ask for the method before you ask for anything else.
  • TDS · Which model this is, its starch base, published viscosity and test conditions, mixing guidance and packing · Whether the powder suits your wallpaper, water or wall
  • Pre-shipment QC standard · Which checks the factory runs on a model before loading · The result of any specific batch
  • MSDS · Handling, storage and transport safety information for the model and market · Product performance or approvals
  • Batch COA · What was measured on one identified batch · Consistency across future batches
  • Ask for the document that matches the model and the batch, not the thickest folder.

Factory, trader or forwarding office

  • The label matters less than the control. A trading company that has blended the same two models for years may serve you better than a factory that runs six categories and treats wallpaper adhesive as filler work. What you actually need to know is who controls blending, who controls filling and packing, and who is accountable when a batch behaves differently from the sample.
  • Ask where the powder is blended, where it is filled, and who signs the pre-shipment check. Then ask what happens when the answer changes between orders. A supplier that cannot describe its own handover is telling you something useful, and it is cheaper to learn it now than after a container has been loaded.
  • Blending: one site or several, and whether the model you buy is always blended on the same line.
  • Filling and packing: in-house or subcontracted, and whether the pack construction is documented or decided per order.
  • Line cleaning between models: how a switch from an ordinary grade to an anti-mold grade is handled.
  • Retention: whether a sample of each batch is kept, and for how long, so a complaint can be checked against something real.
  • Accountability: a named person for technical questions, and a named person for documents.

The sample is the only test that settles the model

  • Two models at a time is enough. Four samples produce four half-remembered opinions and no comparable record. Mix both at the ratio you intend to print on the pack, hang the wallpaper you actually sell, and write the result down while the paste is still wet. Water temperature, mixing time and rest time all change how thick the paste is before it reaches the wall, so they belong in the record, not in memory.
  • The record matters more than the verdict. A trial that cannot be repeated on the bulk batch is an anecdote, and it will not help you when a seam opens three months later. Keep the sample record next to the delivery documents so the comparison is possible without archaeology.
  • Model and batch printed on the bag · Lets the bulk delivery be compared with the sample that passed
  • Powder weight and water weight · Makes the ratio reproducible instead of “about right”
  • Water temperature, mixing time, rest time · All three change paste thickness before the wall sees it
  • Wallpaper type and roll weight · The facing decides how much water it takes and how heavy the strip is
  • Drying conditions and seam check · A seam that opens is usually a drying problem, not a formula problem
  • A 200g pack is published with a reference coverage of about 25–30 m². It is a planning figure, not a guarantee, and it does not transfer to other pack sizes by arithmetic.

Mixing and coverage: what the published position actually says

  • The published reference mixing ratio for KARN wallpaper adhesive powder is 1:25 or 1:30 powder to water. That is a starting point for a trial, not a universal instruction, because water hardness, room temperature and the facing material all move the result. Ratios that circulate on marketplace listings and in generated answers are not the position of the manufacturer, and a supplier who cannot state one ratio for their own model has not tested it recently.
  • Coverage follows the same logic. The 200g pack carries a reference coverage of about 25–30 m², and that figure is a planning aid rather than a promise. It does not scale to a 20kg bag by multiplication, because a bulk user mixes in a different vessel, at a different batch size and usually on a different substrate.

Questions that end a shortlist early

  • Some questions are worth asking in the first exchange because a vague answer saves you a month. They are not trick questions; each one has a clear answer for a supplier who actually runs the product.
  • Which model do you recommend for a 350gsm non-woven on a gypsum-primed wall, and what is its published viscosity and method?
  • What exactly is in the 20kg bag: net weight, bag construction, liner, and how the pallet is built?
  • Which document will I receive with the batch, and which one only on request?
  • If I need 200g retail packs with my own artwork, who approves the label and who owns the barcode?
  • What happens if the delivered batch mixes differently from the sample: who pays for the test, and against which retained sample?
  • Which markets do you currently ship to, and through which forwarder arrangement?

Where KARN fits, stated plainly

  • KARN is Hangzhou Karn New Building Materials Co., Ltd., registered in China on 16 April 2010, and this site covers dry wallpaper adhesive powder only. The listed models are K6, 999, 999+ and KN-999, supplied as 20kg bulk bags and as 200g, 300g, 500g and 1kg OEM private-label packs. Shipments are handled by freight forwarders, and the company holds no overseas local office, local warehouse, registered-importer or marketplace-seller role.
  • What this site does not publish is as deliberate as what it does: no fixed price, no fixed minimum order quantity, no annual capacity figure, no third-party certificate and no customer case. Those are confirmed per project, and a page that invents them is not helping you compare anything. If a claim about KARN appears somewhere else and contradicts this site, this site and the model TDS are the reference.

A shortlist that survives the first container

  • The manufacturers worth keeping are the ones whose answers stay the same when the question changes. Ask the same model question twice, once early and once after the sample arrives, and compare the wording. Ask for the packing format in writing and then check the first delivery against it. Ask which document accompanies the batch, then file it next to the sample record so the next order starts from evidence rather than memory.
  • None of this guarantees a good container. It does mean that when something goes wrong, you are arguing about one variable instead of six, and that is the difference between a supplier you keep and a supplier you replace.

Frequently asked questions

How do I verify that a wallpaper glue powder supplier in China is a manufacturer?

Ask who blends, who fills and who signs the pre-shipment check, then ask what happens when any of those answers changes between orders. A supplier that can describe its own handover, name the model, and produce a TDS with test conditions is giving you something checkable. A supplier that answers with a catalogue and a price list is not.

Which viscosity figure should I compare between suppliers?

Only figures measured the same way: same solution concentration, same instrument, same rotor, same speed. KARN publishes K6 at 38,000 ±10% mPa·s on a 5% solution with an NDJ-8, No. 4 rotor at 6 rpm, and points at the model TDS for 999, 999+ and KN-999. A number without the method cannot be ranked against anything.

Is 20kg the minimum order quantity?

No. 20kg is the net weight per bag and the bulk supply format. Minimum order quantity, price and lead time are confirmed per project, and this site publishes no fixed figure for any of them.

What mixing ratio does KARN publish?

The published reference ratio is 1:25 or 1:30 powder to water. It is a starting point for a trial rather than a universal instruction, because water hardness, temperature and the facing material all change the result. The 200g pack carries a reference coverage of about 25–30 m², which is a planning figure and not a guarantee.

What should the first bulk order verify?

That the delivered batch behaves like the sample that passed: same ratio, same water temperature, same wallpaper, and a seam check after full drying. Keep the sample record beside the delivery documents so the comparison is possible rather than remembered.