About Solvent-borne Attapulgite Rheology Modifier
Our solvent-borne rheology modifier is a fine colloidal attapulgite designed for industrial, protective and primer coatings based on organic solvents. It is used to stop dense pigments and fillers from hard-settling in storage and to give the applied film enough structure to resist sagging on vertical and overhead surfaces.
In a solvent-borne paint the attapulgite needles are dispersed during the grind, where shear separates them and lets them form a network through the vehicle. At rest, that network suspends zinc dust, iron oxides, barytes and other heavy solids, so the paint can be remixed easily after months in the can. Under the shear of spraying or brushing, the network collapses and the paint flows, then recovers quickly enough to hold film thickness on the substrate. Unlike organoclays, this grade does not need a polar activator such as propylene carbonate or alcohol, although a suitable wetting agent or dispersant helps develop full efficiency.
Obsidian Minerals controls the fineness of this grade to keep residue above 45 µm low, protecting gloss and film appearance in primers and topcoats. It performs across the alkyd, epoxy, chlorinated rubber and similar binder systems common in industrial work, although compatibility should always be confirmed in the customer's formulation. Each batch is tested in our NABL-accredited laboratory and shipped with a CoA, Technical Data Sheet and MSDS/SDS.
Typical specifications
| Parameter | Typical Value | Test Method |
|---|---|---|
| Free moisture (105 °C) | ≤ 14 % | Internal method |
| Residue greater than 45 µm | ≤ 1.0 % | Wet sieve, internal method |
| pH (5 % slurry) | 7.5–9.5 | Internal method |
| Loose bulk density | 0.30–0.45 g/cm³ | Internal method |
| Recommended loading | 0.5–1.5 % on total formulation | — |
| Appearance | Cream to off-white fine powder | Visual |
Typical values for guidance. Guaranteed limits are stated on the Technical Data Sheet and batch CoA. Rheological performance depends on the binder, solvent blend and dispersion energy used.
Key features & benefits
Hard-settling prevention
The needle network holds dense pigments and fillers such as zinc dust, iron oxide and barytes in soft, easily remixed suspension, reducing rejected batches and stirring time at the point of use.
Sag control at film build
Fast structure recovery after spraying or brushing lets the solvent-borne coating hold wet film thickness on vertical steel, helping applicators reach specified film builds in fewer passes.
No polar activator needed
This solvent-borne rheology modifier develops structure through mechanical dispersion, so there is no need to add propylene carbonate, alcohol or similar activators to the mill base.
Stable across conditions
The mineral network is largely unaffected by temperature changes during storage and transport, helping maintain consistent in-can viscosity between the factory and the job site.
Applications
Zinc-rich and anti-corrosive primers
Keeps heavy zinc dust and anti-corrosive pigments suspended during storage and supports uniform dry film thickness when primers are sprayed onto blast-cleaned structural and fabricated steel in shops and yards.
Industrial maintenance coatings
Provides sag resistance in high-build epoxy, alkyd and similar maintenance coatings applied by brush, roller or airless spray to tanks, pipelines, structures and plant equipment in the field.
Road marking and heavy-filled paints
Helps solvent-borne road marking and other highly filled paints resist settling of fillers and extenders, so products stay usable from the first to the last drum.
Usage & handling
- Typical loading is 0.5–1.5 % by weight on the total formulation, confirmed by a ladder study.
- Add the powder to the mill base early in the grind, after the wetting agent and before most of the pigment, so it receives full dispersion energy.
- Use a high-speed disperser or mill; insufficient shear leaves needle bundles intact and reduces efficiency.
- Store in a dry area and keep bags closed, as absorbed moisture can change performance in moisture-sensitive systems.
Packaging & supply
- 25 kg or 50 kg HDPE or paper bags
- 1 MT or 1.2 MT FIBC jumbo bags for high-volume paint plants
- Private-label packaging for coatings distributors on request
Frequently asked questions
Where is the solvent-borne rheology modifier added in the process?
Add it to the mill base at the start of the grind, after the wetting agent and before most pigments and fillers. This gives the attapulgite the full shear of the dispersion step, which is what separates the needles and develops structure. Post-adding the powder at let-down usually gives poor efficiency; if post-addition is necessary, ask about our pre-activated gel form.
Can attapulgite replace organoclay in solvent-borne coatings?
In many anti-settling and sag-control applications, attapulgite can replace part or all of an organoclay. It does not need a polar activator and tolerates moisture and temperature changes. Organoclays may still be preferred in very low polarity systems or where high clarity is required. A side-by-side trial in your formulation is the most practical way to decide.
Will this solvent-borne grade affect gloss?
At typical loadings in primers and semi-gloss industrial coatings, the effect on appearance is usually small when the grade is properly dispersed. Low residue above 45 µm helps avoid film defects. In high-gloss topcoats, any mineral thickener can reduce gloss slightly, so the loading should be optimised and measured on drawdowns during development.
What loading should I start with in an anti-corrosive primer?
A starting point of about 0.5 to 1.0 % by weight on the total formulation is common for anti-settling in primers, rising toward 1.5 % where higher sag resistance is required. Prepare three levels, then compare viscosity, sag on a stepped applicator and settling after heat-aged storage to select the final level.