Organoclay for Paint & Coatings

Why Use Organoclay in Solvent-Based Coatings?

We have supplied organoclay to the paint and coatings industry for over 20 years. In that time, the two problems we hear from customers every time are the same: pigment settling during storage (paint separates in the can; pigments form a hard cake at the bottom), and sagging on vertical surfaces during application. Both are solvable — completely — with the right organoclay at the right dosage. If these problems persist after using organoclay, the issue is almost always grade selection, dosage, or dispersion method — not the additive itself. Our technical team troubleshoots these cases daily.

What sets our approach apart: we don't simply recommend a standard grade. We look at your specific solvent system, your formulation cost target, and your production equipment, and we give you the grade that solves your problem at the best price point. The goal is a long-term stable supply relationship — not a one-time sale.

Solvent-based industrial coatings face three persistent formulation problems. Organoclay solves all three simultaneously — in a single additive at treat rates of 0.2–2.0 wt%:

Problem	Root Cause	Organoclay Solution
Pigment settling during storage	Dense pigments (TiO₂, barium sulfate, red iron oxide) sink through low-viscosity medium at rest	Thixotropic gel network immobilizes pigments at rest → no hard cake; easily re-dispersible soft sediment
Sagging of wet film on vertical surfaces	Gravity pulls the wet film downward before cure begins	Gel network rebuilds within seconds of application shear stopping → film holds in place at all film builds
Poor application behavior (too thick to spray or brush)	High-viscosity network present during application	Network breaks down instantly under application shear → low viscosity during spraying, rolling, or brushing → levels smoothly

Organoclay in coatings: A quaternary ammonium-modified montmorillonite that forms a reversible thixotropic platelet network in organic solvent and resin systems. At rest: high viscosity (anti-settling, anti-sagging). Under shear: low viscosity (easy application). After shear: rapid viscosity recovery (no sag). Effective at 0.2–2.0 wt% of total formulation weight.

How Organoclay Works in Coating Systems

When organoclay powder is dispersed under high shear in a solvent or resin system, individual clay platelets (1 nm thick, 200–500 nm wide) exfoliate from stacked aggregates and self-organize through edge-to-face electrostatic interactions into a three-dimensional "house-of-cards" gel network that provides thixotropy:

At rest (storage): Gel network intact → high viscosity → pigments and fillers suspended; no settling or hard cake
Under shear (brushing, rolling, spraying at 1,000–10,000 s⁻¹): Network disrupts → viscosity drops to application viscosity → coating flows and levels
After shear (applied film): Network rebuilds in 5–30 seconds → viscosity returns → wet film holds on vertical surfaces without sagging

Beyond rheology, organoclay platelets align in the drying film — creating a tortuous path for moisture and corrosive ions that measurably improves corrosion barrier performance in epoxy and polyurethane primers. In our testing across 50+ anti-corrosion coating formulations, adding 0.5 wt% CP-34 reduced moisture vapor transmission rate by 18–24% compared to the control formulation without organoclay.

Grade Selection by Coating Type

Coating Type	Key Requirement	Recommended Grade	Treat Rate
Industrial protective coatings (epoxy, PU, alkyd)	Heavy pigment anti-settling, anti-sagging, barrier reinforcement	CP-34, CP-40, CP-388	0.3–1.5 wt%
Marine coatings (antifouling, hull, coal tar epoxy)	Extreme sag resistance, stability in aggressive solvent systems	CP-34, CP-40, CP-EL	0.5–2.0 wt%
Architectural coatings (exterior, interior alkyd)	Anti-settling, good brushability, light color	CP-10, CP-10A, CP-26, CP-100	0.2–0.8 wt%
Transparent coatings, clear lacquers	Clear gel (≤10 μm fineness), no haze	CP-MP, CP-MPS, CP-EDS, CP-EZ10	0.2–1.0 wt%
Wood & furniture coatings	Anti-sagging on vertical panels, leveling, transparency	CP-EZ10, CP-180B, CP-MP	0.2–1.5 wt%
Anti-corrosion primers (zinc-rich, phosphate)	Dense pigment suspension, barrier reinforcement	CP-34, CP-APA, CP-EZ10	0.3–1.5 wt%
Road marking & traffic paint	High sag resistance at thick film build, temperature stability	CP-34, CP-40	0.5–1.5 wt%
High-solid coatings (>80% NV)	Anti-sagging without activator, simple processing	CP-180B, CP-APA (self-activating)	0.5–2.0 wt%

Select by Solvent Polarity

Organoclay grade selection also depends on the polarity of your solvent system. Match your solvent to the grade using Kauri-Butanol (KB) value:

Solvent System	KB Value	Dispersing Type	CP Grade
Aliphatic / mineral spirits / naphtha	<40	Conventional (with activator)	CP-EL, CP-GL, CP-24B
Xylene / toluene / aromatic blends	40–65	Conventional or self-activating	CP-34, CP-40, CP-10, CP-180B
Ketones / esters / ether esters (MEK, butyl acetate)	65–85	Self-activating (no activator needed)	CP-APA, CP-MP, CP-EDS
Wide / mixed / unknown polarity	Any	Wide-range easy-dispersing	CP-388, CP-MPS, CP-MPZ, CP-MP10

Full Product Specifications — Coatings Grades

Grade	LOI (1000°C)	Moisture	Dispersion Fineness	Polarity Range	Dispersing Type
CP-10	30–34%	≤3.5%	≤40 μm	Non-polar to medium	Easy-dispersing
CP-10A	30–34%	≤3.5%	≤40 μm	Non-polar to medium	Easy-dispersing
CP-26	26–29%	≤3.5%	≤40 μm	Non-polar to medium	Easy-dispersing (economical)
CP-100	26–29%	≤3.5%	≤40 μm	Non-polar to medium	Easy-dispersing (economical)
CP-34	28–30%	≤3.5%	Standard	Low to medium-high	Conventional
CP-40	28–30%	≤3.5%	Standard	Low to medium-high	Conventional
CP-180B	29–32%	≤3.5%	Standard	Intermediate to low	Conventional / self-activating
CP-388	31–34%	≤3.5%	Standard	Non-polar to high	Easy-dispersing
CP-APA	32–35%	≤3.5%	Standard	Moderate to high	Self-activating
CP-MP	34–36%	≤3.5%	≤10 μm	Low to high	Easy-dispersing (high clarity)
CP-MPS	31–34%	≤3.5%	≤10 μm	Non-polar to high	Easy-dispersing (high clarity)
CP-EDS	34–37%	≤3.5%	≤10 μm	Medium to high	Easy-dispersing (high clarity)
CP-EZ10	32–35%	≤3.5%	≤10 μm	Low to medium	Enhanced easy-dispersing
CP-MP10	42%	≤3.5%	≤40 μm	Low to high	Self-activating (wide range)

Note on LOI: Higher LOI = higher organic modifier content = better compatibility with polar solvents and higher polarity systems. Grades with dispersion fineness ≤10 μm are recommended for transparent and clear coatings.

How to Disperse Organoclay in Paint

Conventional Grades (CP-34, CP-40, CP-24B, CP-180B, CP-EL, CP-GL)

Add to solvent phase first — add organoclay (0.3–1.5 wt% of total formulation) to the measured solvent before adding resin or pigments
Add polar activator — 95% ethanol at 30–50% of organoclay weight, or propylene carbonate at 20–30% of organoclay weight
High-shear mixing — mix at 1,500–3,000 rpm for 15–20 minutes using a high-speed disperser or Cowles blade
Rest period — allow 10–15 minutes for gel network to fully build before measuring or adding other components
Verify TI — measure thixotropic index (6 rpm / 60 rpm ratio); target ≥ 4.0 for most industrial applications

Self-Activating / Easy-Dispersing Grades (CP-10, CP-APA, CP-MP, CP-388, CP-MP10)

No activator needed — add directly to the solvent or resin phase
Mix at 1,500–2,500 rpm for 15–20 minutes
Post-addition option — CP-10, CP-10A, CP-APA, CP-MP10 can be added after grinding to correct finished-paint viscosity

Key Takeaway — Common Mistakes to Avoid:

Under-mixing: less than 15 min at 1,500+ rpm → incomplete exfoliation → poor gel strength
Excess activator: more than 60% of organoclay weight → gel network disruption → viscosity loss
Adding to resin before solvent: organoclay must contact solvent first for proper wetting
Surfactants before activation: some surfactants interfere with platelet activation — add organoclay first, surfactants after gel forms

Troubleshooting Guide

Problem	Likely Cause	Solution
Low thixotropic index / poor gel	Insufficient shear; wrong activator dose; added to resin instead of solvent	Increase mixing time to 20 min at ≥2,000 rpm; verify activator at 30–50% of organoclay weight; add to solvent phase first
Gel too strong / coating too thick	Overdose of organoclay or activator	Reduce organoclay by 10–15%; check activator not exceeding 50% of organoclay weight
Haze in clear / transparent coating	Coarse particle grade used; incomplete dispersion	Switch to ≤10 μm fineness grade (CP-MP, CP-MPS, CP-EDS); extend mixing time to 20–25 min at 2,500 rpm
Pigment still settling after organoclay addition	Treat rate too low; grade not matched to solvent polarity	Increase organoclay to 0.8–1.2 wt%; verify grade is correct for solvent polarity range
Sagging on vertical surface despite organoclay	Film build too high; TI below 4.0; resin too low viscosity	Increase organoclay by 20%; measure TI at 6/60 rpm; consider increasing base resin viscosity

Frequently Asked Questions

What is organoclay used for in paint?

Organoclay is used as a thixotropic rheology modifier in solvent-based, high-solid, and oil-based paints and industrial coatings. It prevents pigment settling during storage, prevents wet film sagging on vertical surfaces, and maintains good application behavior (low viscosity under brush, roller, or spray shear). Effective treat rate: 0.2–2.0 wt% of total formulation weight.

What is the difference between bentonite and organoclay in coatings?

Bentonite is hydrophilic and only functions in water-based systems — it will not disperse in organic solvents. Organoclay is chemically modified bentonite (quaternary ammonium ion exchange) that disperses in organic media. For solvent-based paints, organoclay is the correct rheology modifier; bentonite is used in waterborne coatings and should not be confused with organoclay.

How do I add organoclay to paint?

Add organoclay to the solvent phase (not resin) before grinding. For conventional grades, add polar activator (95% ethanol at 30–50% of organoclay weight), then mix at 1,500–3,000 rpm for 15–20 minutes, and allow 10 minutes rest. For self-activating grades (CP-APA, CP-MP10, CP-388), omit the activator and add directly. Full dispersion guide with step-by-step instructions →

How much organoclay do I need in paint?

Architectural coatings: 0.2–0.8 wt%. Industrial protective coatings: 0.3–1.5 wt%. Marine coatings and thick-film systems: 0.5–2.0 wt%. Transparent coatings: 0.2–1.0 wt%. Start at the lower end and measure thixotropic index (6 rpm / 60 rpm) — target ≥ 4.0. Contact our technical team with your specific formulation for precise guidance.

Can organoclay be added after grinding?

Yes — easy-dispersing and self-activating grades (CP-10, CP-10A, CP-APA, CP-MP10) can be post-added after grinding to correct finished-paint viscosity. They do not require a pre-gel step or polar activator, making them ideal for post-correction. Conventional grades (CP-34, CP-40) must be added before or during grinding for maximum gel strength.

Which organoclay grade is best for transparent coatings?

For clear lacquers, wood finishes, and transparent topcoats: use ultra-fine particle grades with dispersion fineness ≤10 μm — CP-MP, CP-MPS, CP-MPZ, CP-EDS, or CP-EZ10. These produce clear, haze-free gels even at treat rates above 0.5 wt%. Standard-fineness grades may introduce haze in high-clarity applications.

Can organoclay replace fumed silica in paint?

Yes. In solvent-based systems, organoclay typically delivers higher thixotropic index per unit weight than fumed silica, with better pigment suspension and no dilatancy. At 0.5 wt% in a xylene-based alkyd system, CP-34 achieves thixotropic index ≥ 4.5 vs approximately 3.0–3.5 for fumed silica at the same treat rate, based on our internal comparative testing. Detailed comparison →

What is organoclay thixotropic index in paint?

Thixotropic index (TI) is the ratio of low-shear viscosity to high-shear viscosity (measured at 6 rpm and 60 rpm with a Brookfield viscometer). Organoclay achieves TI values of 3.0–8.0 depending on grade, dosage, and system. A TI of ≥ 4.0 is generally sufficient for pigment anti-settling and sag resistance in standard industrial coatings. Higher TI values (5.0–8.0) are targeted for thick-film and marine coating applications.

Recommended grades for paint & coatings: CP-34 (aromatic systems, with activator) · CP-APA (self-activating, ketone/ester/aromatic) · CP-180B (transparent coatings, fumed silica replacement) · CP-27A (marine & epoxy systems) · CP-EZ (ultra-fine ≤10μm, high-gloss) · CP-EW (waterborne coatings)