Carbomer 940 (Thickener)

Carbomer 940 – High-Performance Crosslinked Polyacrylic Acid Thickener and Gelling Agent

Basic Information

• INCI Name: Carbomer

• CAS Number: 9003-01-4 (common), also 76050-42-5

• Appearance: White, fluffy powder

• Molecular Weight: High molecular weight polymer

• Carboxylic Acid Content: 56.0–68.0% (dried basis)

• Viscosity (0.5% neutralized aqueous dispersion): 40,000–60,000 cP

• Solubility: Swells and disperses in water upon neutralization

• Storage: Store in a cool, dry place, protected from moisture and direct sunlight

Overview
Carbomer 940 is a high-molecular-weight crosslinked polyacrylic acid polymer. It is produced by the polymerization of acrylic acid with small amounts of polyfunctional crosslinking agents, such as allyl ethers of pentaerythritol. This crosslinked structure gives the polymer its unique ability to swell and form highly viscous, clear gels upon neutralization with alkaline agents (e.g., triethanolamine, sodium hydroxide). Carbomer 940 is one of the most widely used rheology modifiers in the cosmetic, pharmaceutical, and personal care industries due to its exceptional thickening, suspending, and stabilizing properties.

Mechanism of Action
In its dry, acidic form, Carbomer 940 has a tightly coiled molecular structure. When dispersed in water and neutralized with a base, the carboxylic acid groups (–COOH) ionize to carboxylate (–COO⁻), creating electrostatic repulsion between the polymer chains. This causes the polymer to uncoil and expand, forming a three-dimensional network that traps water and creates a clear, viscous gel. The resulting gel exhibits excellent clarity, short-flow (non-drip) rheology, and high shear tolerance.

Key Properties

• High thickening efficiency: Provides high viscosity at low concentrations (typically 0.2–1.0%).

• Clear gel formation: Produces sparkling clear gels with excellent transparency.

• Short-flow rheology: Creates non-drip, shear-thinning gels with good spreadability.

• pH responsiveness: Effective in the pH range of 5–8, requiring neutralization for full viscosity development.

• Emulsion stabilization: Improves the stability and homogeneity of emulsion systems.

• Suspending properties: Provides superior suspension of insoluble particles and active ingredients.

• Compatibility: Compatible with a wide range of cosmetic and pharmaceutical ingredients.

Applications

• Cosmetics and personal care: Used in creams, lotions, gels, serums, sunscreens, shampoos, and styling gels to control viscosity, improve texture, and provide clarity.

• Pharmaceuticals: Used as an excipient in topical formulations, ointments, and gels for drug delivery.

• Hand sanitizers: Forms clear, stable gels with high alcohol content.

• Other: Used in household products, industrial formulations, and as a suspending agent.

Recommended Use
Typical usage levels range from 0.2–1.0% of the formulation. Disperse the powder in water with agitation until fully hydrated, then neutralize with an alkaline agent (e.g., triethanolamine, sodium hydroxide, or aminomethyl propanol) to achieve the desired viscosity. Optimize based on specific formulation requirements.

Safety and Handling

• Generally recognized as safe for use in cosmetics and pharmaceuticals at recommended concentrations.

• Low irritation potential; well-tolerated by skin.

• Avoid inhalation of dust – use appropriate personal protective equipment (gloves, dust mask, safety goggles).

• Store in a cool, dry place, away from direct sunlight and moisture.

• Shelf life: typically 24 months under recommended storage conditions.

Quality Assurance
Each batch is tested for viscosity, carboxylic acid content, and clarity to ensure consistent performance.