Cellulose Ethers · CAS 9004-65-3 · From China
Send a mortar plant one drum of under-spec HPMC — viscosity below the label, or the wrong methoxyl substitution — and a whole run of tile adhesive slides off the wall with its open time gone and its QC failed. That failure lands on your name, not the powder's. This page is built so it never reaches your line: the right viscosity grade first, a measured 2% solution second.
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Why HPMC Buying Is Different
HPMC does the invisible work in a dry-mix mortar: it holds the mixing water in the paste so cement can cure instead of the wall sucking it dry, and it builds the body that gives an installer working time. Get the viscosity and substitution right and nobody notices it is there. A tile-adhesive plant that receives cellulose ether one viscosity band low — or cut with starch so the real HPMC content is short — watches water retention collapse, open time fall from twenty minutes to five, and freshly laid tiles slide off a vertical wall. The QC batch fails, the site rejects the delivery, and the anger travels straight up the chain to the person who bought the powder.
The cruel part is that the failure is silent until it is on the wall. A bag of under-spec HPMC looks, weighs and pours exactly like the real thing; the gap only shows in performance, weeks after the money is paid. So this page is built around two instruments rather than a datasheet: the viscosity-by-application matrix that gets you to the correct grade, and the three bench checks that prove the drum in front of you is genuine cellulose ether at its stated viscosity.
Viscosity Is The Axis
Find your product line on the left. A higher viscosity grade holds more water and builds more body; a low grade keeps a self-levelling mix flowing. The surface-treatment column decides instant cold-water dissolution versus controlled dissolution. Viscosity is measured on a 2% aqueous solution, NDJ rotational viscometer, 20 °C.
| Your product line | Viscosity grade (2% NDJ) | Surface treatment | Typical addition |
|---|---|---|---|
| Tile adhesive cement-based C1 / C2 | 40,000–75,000 mPa·s | Instant surface-treated, lump-free in cold mix | 0.2–0.5% · 2–5 kg/ton |
| Wall putty / skim coat interior & exterior | 60,000–100,000 mPa·s | Instant Regular | 0.3–0.5% · 3–5 kg/ton |
| Self-levelling underlayment flow is critical | 400–4,000 mPa·s (low, keeps flow) | Instant | 0.03–0.15% · 0.3–1.5 kg/ton |
| Machine-spray plaster gypsum / cement render | 100,000–150,000 mPa·s | Instant essential — fast pump dissolution | 0.1–0.3% · 1–3 kg/ton |
| Detergent & liquid cleaners thickener / film former | 20,000–75,000 mPa·s | Instant cold-soluble | Per formula · thickening target |
Not sure which band your formula needs? Send the recipe and your water-retention or open-time target — we bracket two grades and sample both.
Tell us your product line — we'll shortlist gradesSee The Actual Product
The Material
White fibrous HPMC — the 2% viscosity is measured onto every COA, not just labelled.
How It Ships
Palletised 25 kg bags, twinned with RDP for one mortar-plant container.
In Use
Water retention and open time for tile adhesive, putty and plaster.
A Measured Number, Not A Printed One
A label that says 200,000 mPa·s means nothing until someone dissolves the powder and turns a viscometer. We do that on every lot, write the reading on the certificate, and keep a sealed retention sample so any dispute settles against a real number.
Send application & target grade
Your product line, the water retention or open time you need, and the viscosity band you run today if any.
We shortlist 1–2 grades
From the matrix, bracketing your line — say a 40,000 and a 75,000 mPa·s HPMC for a tile adhesive.
Samples ship with a protocol
Labelled by grade to Central Asia, South America, the Middle East, Africa or Southeast Asia, with a one-page dissolution guide.
You trial in your own mortar
Check water retention, open time and sag on your cement, in your climate — the only test that settles the grade.
Lock it, measure every lot
The winning grade becomes your contract spec; each lot's measured 2% NDJ viscosity goes on its COA against your figure.
Cut With Starch, PVA Or Talc
A low quote is faked two ways: cutting the cellulose ether with cheap fillers — starch, PVA, talc, limestone — to dilute the real HPMC content, or simply overstating the viscosity grade. Neither shows on the seller's paperwork. These three checks need only a beaker, a crucible and an NDJ viscometer.
Genuine HPMC burns off almost completely — residual ash sits at roughly 1% or below. Burn a weighed sample in a crucible and weigh the residue.
Walk away
High ash → talc, limestone or mineral filler. A drop of iodine turning the solution blue-black → starch cut.
Healthy sign
Low ash, no colour change with iodine — cellulose ether, not a filler blend.
Dissolve 2 g in 100 ml of water. A pure HPMC solution is clear and light-transmitting, with no grit and no sediment at the bottom.
Walk away
Milky, cloudy or turbid, or a layer of undissolved sediment → insoluble filler diluting the cellulose ether.
Healthy sign
A clear, viscous, transparent solution you can read newsprint through.
Put that same 2% solution on an NDJ rotational viscometer at 20 °C and read the actual centipoise against the grade on the bag.
Walk away
Reads 150,000 when the bag says 200,000 → overstated grade. You paid for viscosity that was never in the drum.
Healthy sign
Measured viscosity within tolerance of the stated grade, matching the COA figure.
We run all three at the factory, and you can have an independent third-party pre-shipment inspection repeat them before the balance payment.
Get verified, on-spec HPMCThe Mortar Twin-Pack
Almost no dry-mix plant buys HPMC alone. The two additives that define a modern mortar sit next to each other on the same silo line, so they ride in the same container — one order, one set of documents, freight spread across both.
The cellulose ether holds mixing water so cement hydrates fully, and thickens the mix for open time and anti-sag. Chosen by viscosity grade, as in the matrix above.
Redispersible polymer powder forms a flexible film through the hardened mortar, adding adhesion, deformability and water resistance — the C2 / S1 performance HPMC alone cannot give.
Building a full tile-adhesive or render recipe? We consolidate HPMC, RDP and admixtures against your formula.
See RDP redispersible polymer powderReading The Quotes
Two quotes for "HPMC 200,000, 25 kg bags" can sit far apart and both be honest — because HPMC is not one product. A high-viscosity, high-purity, cold-water-instant grade is a different animal from a low-viscosity regular one, and both are worlds away from cellulose ether cut with starch. When a quote looks impossibly cheap for the grade you asked for, the explanation is rarely generosity — it is a lower measured viscosity, a lower substitution and purity, or the filler blend from the section above.
We quote against your locked viscosity grade, name the factory, and put the measured 2% NDJ figure on the COA — so you compare the same cellulose ether, not the same four letters.
— Matt, XILINK founder · 13 years sourcing & exporting industrial products from China
Send Your Application & Viscosity Grade — Reference Price In 24hThe four levers behind every HPMC quote
Viscosity grade
Higher viscosity means longer, more tightly controlled etherification. A 200,000 mPa·s grade always costs more than a 40,000 one — same chemistry, held to a finer window.
Substitution & purity
Methoxyl and hydroxypropoxyl substitution and the purity of the cellulose feedstock set gel temperature and performance. Tighter, purer grades sit above generic ones.
Surface treatment
Cold-water-instant, surface-treated HPMC takes an extra step to delay dissolution and stop lumping — dearer than a regular grade, but what a site-mixed mortar needs.
Pure HPMC vs cut
A genuine 99%+ cellulose ether costs what it costs. A quote well under the market is usually diluted with starch or PVA — cheaper per bag, failed batch on the wall.
What We Ship
Every lot ships with a certificate of analysis carrying the measured values — 2% viscosity, methoxyl and hydroxypropoxyl substitution, ash, moisture — against your locked grade, plus the production date on the bags. Independent third-party inspection before the balance payment is available on any order.
You don't have to fill a container with one product. A trial order of HPMC from 1 ton rides alongside redispersible polymer powder (RDP) and other dry-mix additives — one container, one set of documents to your port, whether that's in Central Asia, South America, the Middle East, Africa or Southeast Asia.
Building a full mortar line? See the whole construction chemicals range we consolidate from China.
| CAS number | 9004-65-3 |
| Form | White to off-white fibrous / granular powder |
| Viscosity range | 400 – 200,000 mPa·s · 2% aqueous solution, NDJ rotational viscometer, 20 °C |
| Substitution | Methoxyl 19–24% · hydroxypropoxyl 4–12%, by grade |
| Surface treatment | Cold-water instant (surface-treated) or regular |
| Purity / ash | ≥ 99% cellulose ether · ash ≤ 1.5% |
| Gel temperature | 60–90 °C, by grade |
| Packaging | 25 kg multi-wall kraft bags with inner PE liner · palletised & shrink-wrapped or floor-loaded to suit your port |
| Trial order | From 1 ton · consolidates with RDP & admixtures in one container |
| Documents | Per-lot COA with measured 2% viscosity · MSDS · third-party inspection on request |
Straight Answers
As a starting point: tile adhesive runs 40,000–75,000 mPa·s, wall putty 60,000–100,000, machine-spray plaster 100,000–150,000, and self-levelling underlayment a low 400–4,000 so the mix keeps flowing. Detergents use a cold-soluble thickening grade. Send your product line and the water-retention or open-time target and we bracket two grades, then sample both so you confirm it on your own cement.
Dissolve a 2% solution and read it on an NDJ rotational viscometer at 20 °C against the grade on the bag. We measure every production lot this way and print the figure on its COA, and we keep a sealed retention sample so any future lot can be re-tested against your locked number. Pair it with an ash test and a solution-clarity test to rule out starch or filler dilution, and a third-party inspector can repeat all three before you pay the balance.
If the mortar is mixed on site with cold water, or you are thickening a cold liquid such as a detergent, you want surface-treated cold-water-instant HPMC — it disperses without lumping. If you control the mixing and can raise temperature, or dry-blend where dissolution is staged, a regular grade works and costs a little less. Tell us how the powder meets water in your process and we match the treatment.
Trial orders start from 1 ton, and HPMC consolidates with redispersible polymer powder and other dry-mix additives in the same container — the twin-pack most mortar plants buy. One set of shipping documents covers the whole load, and the ocean freight spreads across every product in it, so you can validate the grade and the supply chain before committing to volume.
Common viscosity grades are usually produced within 7–15 days of order confirmation; freshly made cellulose ether beats warehouse stock. Ocean transit depends on your route and is confirmed with the quote. For repeat buyers we schedule staggered shipments so the mortar line never runs short of HPMC.
Right Grade, Measured, Loaded
Tell us what you make — tile adhesive, putty, render, self-levelling, detergent — with whatever numbers you have. We reply within 24 hours with the shortlisted HPMC viscosity grades, the sample plan and the current-month reference price.
Samples with a measured 2% viscosity before any container
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