What is Organoclay? Definition, Properties, How It Works & Uses

Q: What is OrganoClay used for?

Organoclay is used as a rheology modifier in solvent-based paints and industrial coatings (anti-settling, sag control), oil-based drilling fluids (viscosifier and gelling agent), lubricating greases (thickener stable to 180°C), printing inks, adhesives and sealants, cosmetics and personal care products, and water treatment (adsorption of hydrophobic organic contaminants). Typical treat rate: 0.1–2.0 wt% depending on application.

Q: How is OrganoClay made?

Organoclay is made by wet-process ion exchange: natural sodium bentonite is slurried in water at 5–8% solids, then reacted with a quaternary ammonium compound (e.g., dimethyl dihydrogenated tallow ammonium chloride) at 60–70°C for 30–60 minutes. The organic cation displaces the natural Na⁺/Ca²⁺ interlayer cations, converting the hydrophilic clay surface to organophilic. The product is filtered, dried, and milled to ≥95% passing 200 mesh.

Q: What is the difference between bentonite and OrganoClay?

Bentonite is a naturally hydrophilic clay that swells in water — used in water-based drilling fluids and civil engineering. Organoclay is chemically modified bentonite in which the hydrophilic interlayer cations are replaced by organic quaternary ammonium cations, making the clay organophilic — it swells and gels in organic solvents and oils instead of water. They serve entirely different application environments.

Q: What is organoclay bentonite?

Organoclay bentonite (also called organic bentonite or organophilic bentonite) is the same product as organoclay — bentonite clay that has been chemically modified with quaternary ammonium compounds via ion exchange to become organophilic. The terms organoclay, organic bentonite, organophilic clay, and organobentonite are used interchangeably in industry.

Q: What is organoclay made of?

Organoclay is made from two components: (1) a natural smectite clay mineral — typically sodium montmorillonite (CEC 80–120 meq/100g) sourced from high-purity bentonite deposits, and (2) a quaternary ammonium compound, most commonly dimethyl dihydrogenated tallow ammonium chloride or trimethyl hydrogenated tallow ammonium chloride. The organic modifier content is 28–42% by weight (measured as loss on ignition at 1000°C).

Q: What is the CAS number for organoclay?

The most common CAS number for organoclay is 68153-34-4 (Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl, salts with bentonite). EC number: 268-880-0. HS code: 2508.10 (organophilic clay) or 3824.99 depending on application and customs jurisdiction.

Q: Does organoclay need an activator?

Conventional organoclay grades require a polar activator (95% ethanol at 30–50% of organoclay weight, or propylene carbonate at 20–30%) to achieve full platelet exfoliation and maximum gel strength — especially in low-to-medium polarity solvent systems. Self-activating grades (e.g., CP-180B, CP-992) have the activator pre-coated during manufacturing and require no external activator addition. In high-polarity systems (ketones, esters), the solvent itself often provides enough polarity to reduce or eliminate the activator requirement.

Q: How much organoclay should I add?

Typical treat rates: solvent-based coatings 0.3–1.5 wt% of total formulation; oil-based drilling fluids 1.5–4.0 ppb (pounds per barrel); lubricating greases 8–15 wt% on base oil; printing inks 0.5–2.0 wt%; cosmetics 0.5–2.0 wt%. Start at the lower end and increase until the target thixotropic index (typically ≥ 4.0) is achieved. Contact our technical team for formulation-specific guidance.

Q: Is CP organoclay equivalent to other commercial organoclay brands?

Yes. Organoclay is a generic chemical class — all commercial organoclay products use the same fundamental DMDA-modified or specialty-modified montmorillonite chemistry. CP Organoclay manufactures using wet-process ion exchange with equivalent performance verified by side-by-side comparison testing. We provide free samples for direct formulation comparison before any supply decision.

Organoclay Definition

Organoclay is an organically modified layered silicate mineral — produced by replacing the natural inorganic interlayer cations (Na⁺, Ca²⁺) of smectite clay (typically montmorillonite) with long-chain quaternary ammonium cations via ion exchange. This modification converts the inherently hydrophilic clay surface into an organophilic one, capable of swelling, exfoliating, and forming thixotropic gel networks in organic solvents and oils.

CAS No.: 68153-34-4 | HS Code: 2508.10 | EC No.: 268-880-0

In practical terms: bentonite swells in water; organoclay swells in oil and organic solvents. That single difference — achieved by one chemical modification step — is what makes organoclay the standard rheological additive for solvent-based coatings, oil-based drilling fluids, and lubricating greases worldwide.

What is Organoclay Made Of?

Organoclay is made from two primary components:

Component	Material	Key Parameter
Base clay	Natural sodium montmorillonite (high-purity bentonite)	CEC 80–120 meq/100g; platelet size 200–500 nm × ~1 nm thick
Organic modifier	Quaternary ammonium compound — typically dimethyl dihydrogenated tallow ammonium chloride (DMDA) or trimethyl hydrogenated tallow ammonium chloride	Final organic content: 28–42 wt% (measured as LOI at 1000°C)

The high cation exchange capacity of montmorillonite (80–120 meq/100g) allows efficient ion exchange with the bulky quaternary ammonium cation, while its large platelet aspect ratio (200–500:1) enables effective gel network formation at dosages as low as 0.3–1.5 wt%.

How is Organoclay Made?

Industrial organoclay production uses the wet process, which delivers higher purity and more complete ion exchange than the alternative dry process:

Beneficiation: Mine and purify high-purity sodium bentonite — remove impurities (quartz, feldspar), classify particle size
Slurry preparation: Disperse the purified bentonite in water to 5–8% solids concentration
Ion-exchange reaction: Add the quaternary ammonium compound dissolved in hot water (60–70°C); react for 30–60 minutes under agitation — the organic cation displaces Na⁺/Ca²⁺ from the clay interlayer:
Clay–Na⁺ + [R₄N]⁺Cl⁻ → Clay–[R₄N]⁺ + NaCl
Filtration and washing: Remove by-product salts (NaCl) by filtration and repeated washing
Drying and milling: Dry at controlled temperature (≤120°C); mill and classify to ≥95% passing 200 mesh (74 μm)

Key Takeaway — Wet vs Dry Process:

Wet process: higher purity, more complete ion exchange, better batch-to-batch consistency — preferred for coatings and cosmetics
Dry process: lower production cost, simpler — used for some drilling-grade products
At equal dosage, wet-process organoclay delivers higher thixotropic index and better transparency in clear coatings

How Organoclay Works — The Thixotropic Mechanism

When organoclay powder is dispersed in an organic solvent system under high shear (1,500–3,000 rpm for 15–20 minutes), the following sequence occurs:

Wetting: Organic solvent molecules and polar activator (if used) enter between the organoclay platelet stacks, reducing interlayer attraction
Swelling: The interlayer gallery expands from ~1.0–1.2 nm (dry) to 1.8–4.2 nm as solvent and activator intercalate
Exfoliation: High shear separates the stacks into individual platelets (1 nm thick, 200–500 nm wide)
Network formation: Exfoliated platelets self-organize through edge-to-face electrostatic interactions into a "house-of-cards" gel network that immobilizes the liquid phase

This network produces the defining property of organoclay — thixotropy:

Condition	Network State	Viscosity	Practical Effect
At rest (storage)	Intact "house-of-cards"	High	Pigments stay suspended; no settling
Under shear (application)	Network disrupted	Low	Easy pumping, spraying, brushing
After shear (applied film)	Network rebuilds (seconds to minutes)	High returns	No sagging on vertical surfaces

Key Physical Properties

Property	Typical Value
Physical form	Free-flowing white to light-yellow powder
Moisture content (105°C, 2 hr)	≤ 3.5%
Particle size (200 mesh, 74 μm)	≥ 95% passing
Bulk density	0.35–0.60 g/cm³
Specific gravity	~1.6–1.7 g/cm³
Loss on ignition (LOI, 1000°C)	26–42% (grade-dependent; indicates organic modifier content)
Thixotropic index (1 wt% in xylene)	≥ 4.0 (conventional grades); ≥ 3.5 (self-activating grades)
Shelf life	2 years (sealed, dry, below 50°C)
GHS hazard classification	Not classified as hazardous

Types of Organoclay

Type	Activation	LOI Range	Best For	CP Grades
Conventional (Type A)	Requires polar activator (ethanol or propylene carbonate)	26–32%	Aromatic / medium-polarity solvent systems; maximum gel strength	CP-34, CP-40, CP-982
Self-Activating (Type B)	No activator needed (PC pre-coated)	32–42%	High-solid coatings; simplified plant processing; OBM drilling	CP-180B, CP-992
Water-Dispersible (Type C)	Water dispersion	12–20%	Waterborne coatings; cosmetics; aqueous systems	CP-EW
Grease Grade (Type D)	Heat + shear	28–35%	Lubricating grease thickener; stable to 180°C	CP-250A

How to Choose the Right Organoclay Grade — Polarity Compatibility

Grade selection depends primarily on the polarity of the continuous phase solvent or oil. The Kauri-Butanol (KB) value is the standard measure:

Polarity Level	KB Value	Typical Solvents	Recommended Grade	Activator
Non-polar	< 30	Mineral spirits, aliphatic naphtha, hexane	CP-40	Required
Low-medium polarity	30–50	White spirit, VM&P naphtha, mineral oil	CP-34	Required
Medium polarity	50–65	Xylene, toluene	CP-34 / CP-180B	Optional (SA grade: none)
High polarity	65–85	Butyl acetate, MEK, ketone/ester blends	CP-180B	None required
Aqueous	—	Water, water-cosolvent blends	CP-EW	Water dispersion

In oil-based drilling fluids, base oil type determines grade choice: diesel/mineral oil base → CP-34 or CP-982; synthetic base (IO, LAO) → CP-992 or CP-180B.

What is Organoclay Used For?

Industry	Primary Function	Typical Treat Rate
Paints & Industrial Coatings	Anti-settling, anti-sagging, thixotropy	0.3–1.5 wt%
Oil-Based Drilling Fluids (OBM)	Viscosity building, suspension, filtration control	1.5–4.0 lb/bbl
Lubricating Greases	Thickener (no drop point); thermal stability	8–15 wt% on base oil
Printing Inks	Thixotropy, anti-misting, anti-settling	0.5–2.0 wt%
Adhesives & Sealants	Sag resistance, thixotropic structure	0.5–2.0 wt%
Cosmetics & Personal Care	Suspension, texture, emulsion stability	0.5–2.0 wt%
Water Treatment	Adsorption of hydrophobic contaminants	Application-specific
Construction & Asphalt	Viscosity modification, anti-settling	0.3–1.5 wt%

How We Explain Organoclay to New Customers

When a customer contacts us for the first time, they often say: "We need bentonite." This is the single most common misunderstanding we encounter. Bentonite is a naturally occurring mined clay mineral — it is hydrophilic, it swells in water, and it is used in water-based drilling fluids, civil engineering, and foundry applications. Bentonite alone will not function as a rheology modifier in paints, oils, or greases.

Organoclay is bentonite that has gone through an amine modification process — the natural interlayer cations are replaced with organic quaternary ammonium compounds, converting the clay from hydrophilic to organophilic. That modification is what makes organoclay work in oil-based systems: paints, coatings, drilling fluids, lubricating greases, printing inks, sealants, and cosmetics. If you need something that disperses in an organic solvent or oil and provides viscosity control, thixotropy, pigment suspension, or anti-settling performance — that is organoclay, not bentonite.

Our practical one-sentence description when introducing organoclay to a new customer: "It is a modified bentonite clay that gives you thixotropy and suspension in any oil-based or solvent-based system — high viscosity at rest, low viscosity under shear, and it stays stable over the full temperature range of your application."

What is the Difference Between Bentonite and Organoclay?

Property	Natural Bentonite	Organoclay
Surface character	Hydrophilic	Organophilic (hydrophobic)
Swelling medium	Water	Organic solvents / oils
Interlayer spacing	~1.0–1.2 nm (dry)	~1.8–4.2 nm (expanded after modification)
Interlayer cation	Na⁺, Ca²⁺ (inorganic)	Quaternary ammonium (organic)
Application environment	Water-based drilling fluids, civil engineering, foundry	Solvent coatings, OBM drilling, grease, cosmetics
Modification required	No	Yes — ion exchange with quaternary ammonium compounds

Organoclay vs Other Rheology Modifiers

Property	Organoclay	Fumed Silica	HPMC	Castor Oil Wax
Compatible system	Solvent / oil-based	Solvent / water	Water-based	Solvent-based
Thixotropy	Excellent	Good	Moderate	Good
Anti-settling	Excellent	Good	Poor	Moderate
Temperature stability	Excellent (to 180°C+)	Good	Fair	Poor (melts <85°C)
Transparency in clear coat	Good–Excellent	Poor (hazy)	N/A	Poor
Typical dosage	0.3–2.0 wt%	0.5–3.0 wt%	0.1–1.0 wt%	0.5–3.0 wt%

Key Takeaway: Organoclay is the preferred rheology modifier when you need thixotropy + anti-settling + temperature stability in a single additive in solvent or oil-based systems. Fumed silica offers slightly broader system compatibility but at higher haze and cost. Castor oil wax loses effectiveness above 85°C and is not suitable for high-temperature applications.

Frequently Asked Questions

What is OrganoClay used for?

Organoclay is used as a rheology modifier across multiple industries: solvent-based paints and industrial coatings (anti-settling, anti-sagging, thixotropy), oil-based drilling fluids (viscosifier), lubricating greases (clay thickener, stable to 180°C), printing inks, adhesives, cosmetics, and water treatment. Treat rates range from 0.3–1.5 wt% in coatings to 8–15 wt% in lubricating greases. See all application pages →

How is OrganoClay made?

Organoclay is made by wet-process ion exchange: sodium bentonite is slurried in water (5–8% solids), reacted with a quaternary ammonium compound at 60–70°C for 30–60 minutes, then filtered, washed, dried (≤120°C), and milled to ≥95% passing 200 mesh. The organic modifier content (loss on ignition at 1000°C) is 28–42 wt% depending on grade. Wet process vs dry process comparison →

What is the difference between bentonite and OrganoClay?

Bentonite is naturally hydrophilic (swells in water) and is used in water-based drilling fluids, civil engineering, and foundry. Organoclay is chemically modified bentonite — the water-swelling interlayer cations (Na⁺/Ca²⁺) are replaced by organic quaternary ammonium cations, converting it to organophilic (swells in oils and solvents). They serve completely different application environments. Learn more about bentonite →

What is organoclay bentonite?

Organoclay bentonite — also called organic bentonite, organophilic bentonite, or organobentonite — refers to the same product: bentonite clay chemically modified with quaternary ammonium compounds to become organophilic. The terms organoclay, organic bentonite, organophilic clay, and organobentonite are used interchangeably in industry literature and trade documentation.

What is organoclay made of?

Organoclay contains two components: high-purity sodium montmorillonite (CEC 80–120 meq/100g) and a quaternary ammonium compound (typically dimethyl dihydrogenated tallow ammonium chloride). The finished product is 58–72% clay mineral and 28–42% organic modifier by weight (measured as LOI at 1000°C).

What is the CAS number for organoclay?

The primary CAS number is 68153-34-4 (Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl, salts with bentonite). EC number: 268-880-0. HS code: 2508.10 (organophilic clay) or 3824.99 depending on the customs jurisdiction. We provide full product identification documentation with every shipment. Trade and HS code information →

Does organoclay need an activator?

Conventional organoclay grades (e.g., CP-34) require a polar activator — 95% ethanol at 30–50% of the organoclay weight, or propylene carbonate at 20–30% — added during high-shear dispersion in low-to-medium polarity solvents. Self-activating grades (e.g., CP-180B, CP-992) require no activator — the propylene carbonate is pre-coated during manufacturing. In high-polarity systems (MEK, butyl acetate, ketone blends), the solvent itself may reduce or eliminate the activator requirement. Full dispersion guide →

How much organoclay should I add?

Typical treat rates: solvent-based coatings 0.3–1.5 wt%; oil-based drilling fluids 1.5–4.0 lb/bbl; lubricating greases 8–15 wt% on base oil; printing inks and adhesives 0.5–2.0 wt%; cosmetics 0.5–2.0 wt%. Start at the lower end of the range, measure the thixotropic index (target ≥ 4.0 for most coatings applications), and adjust. Contact our technical team for formulation-specific guidance.

Is CP organoclay equivalent to other commercial organoclay brands?

Yes. Organoclay is a defined chemical class — all commercial grades use the same fundamental DMDA-modified or specialty-modified montmorillonite chemistry and wet-process manufacturing. CP Organoclay performance is verified by side-by-side comparison testing with equivalent grades. We provide free samples (200 g–2 kg) for direct formulation comparison before any supply decision. Grade matching guide →

What is Organoclay?