PAC-R — also called PAC-HV — is polyanionic cellulose in its high-viscosity grade. It cuts fluid loss and adds viscosity to the water phase from a single product. Ironstone supplies drilling-grade PAC-R with a certificate of analysis for every batch.
PAC-R does two jobs at once: it reduces API fluid loss by building a thin, low-permeability filter cake, and it raises the viscosity of the water phase. That makes it the choice for simpler water-based programs and top-hole sections where you want body and filtration control from one product. Like all polyanionic cellulose, it tolerates salt and hardness far better than technical-grade cellulose, so it keeps performing in seawater and brine.
Choose PAC-R (high viscosity) when you want viscosity and filtration control together — for example a low-solids water-based mud that needs body. Choose PAC-LV (low viscosity) when the mud is already at target rheology and you only want the filtrate down without thickening it. Both are the same polymer chemistry at different viscosity levels, so the filtration performance is comparable; the difference is how much viscosity each adds.
| Parameter | Value | Basis |
|---|---|---|
| Appearance | Off-white 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 – 8 | Manufacturer COA |
| Apparent viscosity | ≥ 50 mPa·s (cP) | Manufacturer COA — we specify this |
| Filtrate volume | ≤ 23 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.
We specify PAC-R on apparent viscosity and filtrate volume, and our order states both. Those are the two numbers a high-viscosity PAC is bought for, and they are what the certificate of analysis has to show for your batch.
We do not specify on purity. A purity figure does not predict filtration, and it can be raised by adding material that is not polymer at all. The reasoning is set out in full on the PAC-LV page. Tell us the viscosity and filtrate your fluid needs and we quote against them.
As with any cellulose polymer, dosage is set by pilot testing against your filtrate and viscosity targets in your own base fluid, then scaled to the system volume. Because PAC-R adds viscosity, watch the rheology as you treat so you do not overshoot. We include the technical data sheet with dosage guidance when we quote.
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.