Hydroxyethyl acrylate/sodium acryloyldimethyl taurate copolymer is a synthetic polymer used primarily in cosmetic and personal care products as a rheology modifier, stabilizer, and emulsifier. It is widely known under commercial names like Sepinov EMT 10, and is valued for its sensory softness, excellent skin compatibility, and thickening performance in both aqueous and emulsion systems.

1. Name breakdown and chemical structure

• Hydroxyethyl acrylate (HEA):
  A hydrophilic monomer with a terminal hydroxyl group, contributing to water compatibility and mild film-forming properties.

• Sodium acryloyldimethyl taurate (NaADMT):
  A taurine-based anionic monomer with a sulfonate group and high electrolyte tolerance, giving the copolymer ionic character and emulsifying properties.

• Copolymer:
  A combination of the two monomers (HEA and NaADMT), structured into a random or block polymer chain, often pre-neutralized and delivered as a pre-swollen aqueous gel or dry powder.

The resulting copolymer is a hydrogel-forming polymer that is non-ionic to anionic in character, highly versatile, and compatible with a wide range of cosmetic actives, including acids, salts, alcohols, and oils.

2. Physical and chemical properties

• Appearance: white powder or transparent gel (pre-neutralized version)

• Solubility: readily dispersible in water, forms clear, stable gels

• pH range: stable from 3 to 10

• Electrolyte tolerance: excellent → compatible with ionic actives and salt-containing formulas

• Alcohol compatibility: stable in the presence of up to 50% ethanol

• Sensory profile: soft, smooth, non-sticky, silicone-like feel on skin

3. Functions and cosmetic applications

a. Rheology modification / thickening

• Efficient thickener for serums, gels, emulsions, and lotions

• Allows for precise viscosity control without affecting clarity

• Provides pseudoplastic flow → easier spreadability and pumpability

b. Emulsion stabilization

• Acts as a co-emulsifier and stabilizer, especially in oil-in-water (O/W) systems

• Prevents phase separation even with high oil loads or challenging actives

• Can replace traditional emulsifiers in minimalist or clean-label formulas

INCI Funcions

Emulsion stabilizer. Emulsions are thermodynamically unstable. Emulsion stabilisers improve the formation and stability of single and double emulsions. It should be noted that in the structure-function relationship, molar mass plays an important role.

Viscosity control agent. It controls and adapts viscosity to the required level for optimal chemical and physical stability of the product and dosage in gels, suspensions, emulsions, solutions. 

4. Compatibility and formulation benefits

• Compatible with:

  • Acids (e.g. glycolic, lactic, salicylic)

  • Electrolytes and salts (e.g. magnesium sulfate, sodium chloride)

  • Alcohol (e.g. ethanol, isopropyl alcohol)

  • Cationic ingredients (in some systems with proper pH control)

• Can be used cold-process, reducing energy use in manufacturing

• Enables creation of clear or translucent formulations

• Compatible with pigments and sunscreens for colored cosmetics or SPF products

5. Safety and environmental considerations

• Generally regarded as safe (GRAS) for topical use

• Non-sensitizing and non-irritating

• Used at low concentrations (0.1–2%), making it effective and efficient

• Not biodegradable (being synthetic), but used in low amounts

• Considered acceptable in eco-conscious formulations due to its non-toxic, non-bioaccumulative nature

6. Typical use levels and examples

• Clear serums → 0.5–1%

• Moisturizing gels → 1–1.5%

• Emulsions and lotions → 0.3–0.8% as a stabilizer

• Alcoholic gels → 0.5–2% with up to 50% ethanol

7. Conclusion

Hydroxyethyl acrylate/sodium acryloyldimethyl taurate copolymer is a versatile, high-performance rheological modifier and stabilizer, ideal for modern cosmetic formulations that require clarity, stability, pleasant texture, and broad compatibility. It allows formulators to create elegant, stable products even under challenging conditions (high alcohol, acids, salts), while enhancing user experience through its sensory properties.

UNII: 86FQE96TZ4

CAS: 111286-86-3    

Synonyms:

• Sepinov EMT 10
• Hydroxyethyl acrylate/sodium acryloyldimethyl taurate copolymer (45000 mpa.s at 1%)
• Hydroxyethyl acrylate/sodium acryloyldimethyl taurate copolymer (70000-100000 mpa.s at 1.5%)