What it is
Acrylates/Hydroxyethyl Acrylate Copolymer is a synthetic polymer formed by copolymerizing one or more acrylic acid or methacrylic acid esters with hydroxyethyl acrylate (HEA). The hydroxyl groups contributed by the HEA monomer introduce hydrophilicity and improve adhesion to skin and hair surfaces. In cosmetic formulations, the polymer forms a thin, flexible film upon drying that helps bind pigments, fix active ingredients in place, and improve wear. It also acts as a rheology modifier, increasing viscosity and stabilizing oil-in-water emulsions. It is used in sunscreens, foundations, primers, serums, and hair care products. Concentrations range from approximately 0.5% as a viscosity modifier to 25% in film-forming or fixative applications. The large polymer chain size limits dermal penetration, and the polymer itself exhibits low acute toxicity; residual unreacted monomers are the primary safety consideration in manufacturing.
Safety & warnings
The polymer itself has low dermal penetration and low acute toxicity due to its high molecular weight. The main safety concern is residual unreacted acrylate monomers, which can reach up to 1500 ppm but typically range 10–1000 ppm; residual acrylic acid and HEA monomers are known skin sensitizers and irritants. The CIR concluded the ingredient class is safe as formulated when irritation is avoided. Individuals with known acrylic or acrylate allergies should exercise caution. The monomer HEA carries GHS hazard classifications for skin corrosion/irritation (H314), skin sensitization (H317), and aquatic toxicity (H400), though these apply to the monomer, not the finished polymer.
Origin & sourcing
Acrylates/Hydroxyethyl Acrylate Copolymer is produced by free-radical emulsion or solution polymerization of acrylic monomers including hydroxyethyl acrylate (HEA), acrylic acid, methacrylic acid, and/or their simple esters. HEA itself is synthesized by reacting ethylene oxide with acrylic acid in the presence of a metal catalyst. The resulting copolymer is fully synthetic with no natural botanical source.
History
Acrylate polymers became widely used in cosmetics from the 1970s onward as film formers and rheology modifiers. The Cosmetic Ingredient Review (CIR) Expert Panel assessed Acrylates Copolymer and 33 related cosmetic acrylate ingredients in 2002, concluding they were safe when formulated to avoid skin irritation. An amended safety assessment covering acrylates copolymers was subsequently published to reflect updated usage data and formulation guidance.
Questions everyone asks
What does Acrylates/Hydroxyethyl Acrylate Copolymer do in sunscreen?
In sunscreen formulations it acts as a film former and emulsion stabilizer, helping create a uniform layer on skin that improves the even distribution of UV filters and contributes to long-wear performance.
Is this ingredient safe for sensitive skin?
The high-molecular-weight polymer itself has low irritation and sensitization potential. However, trace residual acrylate monomers from manufacturing can sensitize susceptible individuals.
Is Acrylates/Hydroxyethyl Acrylate Copolymer natural or synthetic?
It is fully synthetic, produced by free-radical polymerization of petrochemical-derived acrylate monomers. It has no botanical or mineral origin.
How is this copolymer different from plain Acrylates Copolymer?
The inclusion of hydroxyethyl acrylate (HEA) monomer introduces hydroxyl groups into the polymer backbone, increasing hydrophilicity and improving adhesion to skin compared with simpler all-alkyl acrylate copolymers.