PAC-LV is polyanionic cellulose in its low-viscosity grade — a filtration-control polymer for water-based drilling fluid that cuts fluid loss without adding much viscosity. Ironstone supplies drilling-grade PAC-LV with a certificate of analysis for every batch.
PAC-LV reduces API fluid loss by helping form a thin, low-permeability filter cake on the wellbore wall, so very little water passes into the formation. The low-viscosity grade is chosen when the mud is already at the target rheology and you only want to bring the filtrate down — common in dense, solids-loaded, and brine systems where extra viscosity would be a problem. Because it is a purified, high-substitution cellulose, PAC-LV keeps working in seawater and field brines where cheaper cellulose grades lose performance.
| Parameter | Value | Basis |
|---|---|---|
| Appearance | Off-white to cream free-flowing powder | Manufacturer COA |
| Starch or starch derivatives | Absent | Manufacturer COA (API 13A method) |
| Moisture | ≤ 10% | Manufacturer COA |
| Degree of substitution | ≥ 0.90 | Manufacturer COA |
| pH (1% solution) | 6.0 – 8.5 | Manufacturer COA |
| Apparent viscosity | ≤ 40 mPa·s (cP) | Manufacturer COA — we specify this |
| Filtrate volume | ≤ 16 mL | Manufacturer COA — we specify this |
| Particle size | Stated on the certificate of analysis | Manufacturer COA |
Ironstone does not operate a laboratory. Every figure in this table comes from the manufacturer’s certificate of analysis or data sheet, and the certificate for your batch states the exact figures. Independent testing or inspection before loading can be arranged on request.
Purity is the share of the dry solids that is active polymer. The balance is mainly residual reaction salt and sodium glycolate, with smaller amounts of unreacted cellulose and residual alkali, and in the bag you receive, water.
Purity is not a tested requirement. API Spec 13A and China’s GB/T 5005 both recommend PAC purity above 96% NaCMC on a dry basis, but both carry it as a note rather than a requirement, and a note in a standard is informative by drafting convention: it cannot contain a requirement. What the standards test on PAC is four things: that starch is absent, moisture at or below 10%, apparent viscosity, and filtrate volume. On a low-viscosity grade none of those four measures active content, so material well below 96% can pass all of them and be sold as API grade.
Treat any supplier datasheet carefully when it prints a table headed “API 13A” with rows for purity, degree of substitution and pH. Those rows are the vendor’s own. None of the three is in the standard.
Published datasheets for drilling-grade PAC run from about 70% to 98% active polymer, and some vendors quote as low as 65%. Much of what is sold as PAC therefore sits well below the level its own standard recommends, and at the bottom of that range you are buying technical-grade cellulose with a PAC label.
Ask for the figure in writing, with the test method and the basis. Then read it carefully, because the number is blind to adulteration, and worse than blind. Purity is measured either by subtracting the salt and the glycolate from the total, or by washing the sample in ethanol and weighing what stays behind. Starch, guar and mineral filler survive both routes: they carry no salt or glycolate, and they do not dissolve in ethanol. So adding filler raises the reported purity, by roughly one point for every point added. A 20% starch cut turns a genuine 96% product into a reported 96.8% while the polymer you actually receive falls to about 77%.
What catches that is a panel of checks, not one number. The iodine test finds starch, though not modified or waxy starches, and it does not find guar at all. Degree of substitution is the better cross-check: it counts carboxymethyl groups per gram, so dilution with any non-ionic polysaccharide pulls it down in proportion. A certificate showing 95% purity and a degree of substitution at or above 0.90 is far harder to fake than purity alone. A sulphated ash figure catches mineral filler. And the performance tests are the real defence: apparent viscosity and filtrate volume, run on your own fluid, will fail a starch-cut product whatever the purity line says.
Basis matters just as much. A 95% figure on a dry basis is 85.5% active polymer in the bag at the 10% moisture ceiling, and about 87% at the 8% moisture datasheets typically report, against 95% if the same figure were quoted as shipped. Almost no supplier states which one they mean. Make every supplier state the basis and the moisture, then convert every offer the same way.
One caution on comparing this way. Cost per tonne of active polymer is the right first cut, not the whole decision. Viscosity grade is not interchangeable, so cheap active polymer in the wrong grade is worth nothing to you. Chain length drives filtration control more than the mass of polymer does, so two products both at 95% can give different filtrate. In a saturated brine a higher-substitution 90% product can beat a low-substitution 98% one. And the salt is not always dead weight: it matters less in a salt mud than in a fresh-water system, where the extra chloride loads the fluid and clouds chlorides as a contamination reading. Use active content to rank comparable offers, not to choose between grades.
Which is why we specify performance rather than purity. Our order states the apparent viscosity and the filtrate volume the batch has to hit, and the certificate has to show them. Those are the numbers your fluid actually runs on, and unlike a purity figure they cannot be improved by adding filler. Tell us the filtrate you need and we quote against it.
Dosage depends on the filtrate target, the base fluid, and the solids in the system, so it is set by pilot testing rather than a fixed number: treat a measured sample of mud with increasing amounts, measure the filtrate after each step, and scale the amount that works to the full system volume. When we quote, we include the technical data sheet with the manufacturer’s dosage guidance as a starting point.
Indicative, reviewed monthly. Updated 2026-08-13. This is not a quotation: a firm price needs your volume and port.
We quote rather than publish a list price. Polymer and freight prices both move, so a published number is out of date before you read it. Send your volume, your grade and your delivery port by WhatsApp or email. We reply within one working day, and we hold the price we quote for seven days against that volume and that port.
What we take responsibility for.Our purchase order states the specification on this page, not the supplier’s typical values. Before we release payment to the factory we require a certificate of analysis for your batch, and that certificate must include the starch test result. If it fails the specification we reject the batch: that is our problem, not yours. Independent inspection before loading is available on request, at cost.