Acrylates copolymer is a common ingredient found in a wide variety of personal care and cosmetic products, from makeup to hair gels and sunscreens. This substance often appears on ingredient lists. Acrylates copolymer is a type of large synthetic molecule created by linking together smaller chemical units called acrylates. Its prevalence is due to its versatility in modifying the texture, look, and performance of many daily-use products.
Chemical Composition and Structure
A copolymer is a large molecule built from at least two different types of smaller units, known as monomers. Acrylates copolymer is a synthetic copolymer constructed from two or more acrylate monomers. These monomers are typically derived from acrylic acid and methacrylic acid, along with their various esters or salts.
The process of polymerization links these monomers into large, stable chains with high molecular weights. The specific combination and ratio of different acrylate monomers determines the final properties of the copolymer, such as flexibility or hardness. Some acrylates copolymers are also cross-linked, meaning the polymer chains are chemically bonded to each other, creating a robust network structure.
Primary Functions in Product Formulation
Acrylates copolymer is valued by formulators for its ability to modify the physical characteristics of a product, serving several distinct roles in formulation:
- Viscosity control: It acts as an efficient thickener, giving liquids and gels a desirable, spreadable consistency. This ensures products like lotions and shampoos are stable.
- Film-former: It creates a thin, flexible barrier when applied to the skin or hair. This film can help lock in active ingredients and impart water-resistant qualities to products like sunscreens.
- Emulsion stabilizer: It prevents the oil and water phases of a product, such as a moisturizer, from separating over time.
- Suspending agent: It keeps insoluble particles, such as pigments in makeup or exfoliating beads, evenly distributed throughout the product.
Safety and Regulatory Considerations
The primary safety concern is its application to the skin. Due to its large molecular size, the copolymer is considered too large to penetrate the skin barrier and enter the bloodstream. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that acrylates copolymers are safe for use in cosmetics when formulated to avoid irritation.
While the polymer itself is safe, the initial monomers used to create it, such as acrylic acid, can be irritating in their unpolymerized form. Manufacturers must ensure that residual levels of these monomers are kept extremely low. In rare instances, individuals with sensitive skin may experience mild irritation or an allergic reaction, making a patch test a reasonable precaution.
A growing concern relates to the environmental fate of acrylates copolymer when rinsed down the drain. Many acrylates copolymers are classified as non-biodegradable solid synthetic polymers. When these ingredients enter wastewater systems, they may contribute to microplastic pollution, as they are not easily filtered or broken down. Consequently, regulatory bodies, such as the European Chemicals Agency (ECHA), have proposed restrictions on intentionally added microplastics, including certain solid acrylates copolymers used in cosmetics.