Ethylene/Propylene Copolymer is a synthetic hydrocarbon-based polymer that functions as a film-forming agent, viscosity-increasing agent, and lubricant. It is primarily utilized to stabilize oil-based formulations, providing a smooth, non-greasy texture and enhancing the longevity of pigments in color cosmetics.
- INCI Name:
- Ethylene/Propylene Copolymer
- Chemical/Scientific Name:
- 1-Propene, polymer with ethene
- Common Aliases:
- Ethylene-propylene rubber (EPR), Poly(ethylene-co-propylene)
| Category: | Texture Enhancers |
| Source Origin: | Synthetic (Petrochemical) |
| Comedogenic Rating: | 0 |
| Primary Industries: | Cosmetics, Skincare, Haircare |
| Solubility: | Lipophilic (Oil-soluble) |
At a Glance: Properties & Effects
| Texture Enhancement | |
| Formula Stability | |
| Hydration/Moisture | |
| Irritation Risk |
- Primary Benefits:
- Creates a flexible, breathable film on the skin surface.
- Prevents oil separation (syneresis) in anhydrous formulas.
- Improves the spreadability and “slip” of heavy creams and ointments.
- Enhances the water resistance of sunscreens and waterproof makeup.
- Potential Risks:
- None identified for topical use in cosmetics.
Biological Action & Cosmetic Profile
At a molecular level, this copolymer consists of long-chain hydrocarbons synthesized from ethylene and propylene monomers. Its primary role is physical rather than biological; it does not penetrate the skin barrier due to its high molecular weight. Instead, the polymer organizes the liquid oil phase of a formula into a structured gel-like matrix. This transition increases the viscosity of the product without the tackiness associated with many natural waxes or resins.Manufacturers frequently integrate this ingredient into lip products and foundations to ensure pigment suspension and uniform application. By forming a cohesive film, the copolymer reduces transepidermal water loss (TEWL) indirectly, though it is not classified as a primary humectant. Its lipophilic nature makes it exceptionally effective at thickening non-polar oils like Isododecane or Hydrogenated Polyisobutene.
Broader Applications & Origins
While widely recognized for its contribution to cosmetic textures, Ethylene/Propylene Copolymer originates from the industrial elastomer sector. Its chemical inertness and resistance to heat and UV degradation make it a preferred stabilizer for long-wear skincare. In haircare, the polymer acts as a conditioning agent that coats the hair shaft, smoothing the cuticle and providing heat protection during styling.
Routine Integration
- Synergies:
- Emollients: Combines effectively with Squalane or Mineral Oil to create elegant, silk-textured balms.
- Silicones: Enhances the film-forming properties of Dimethicone for improved skin-blurring effects.
- UV Filters: Improves the distribution of organic and inorganic sun filters on the skin surface.
Clinical Consensus & Safety
Dermatological safety assessments conducted by the Cosmetic Ingredient Review (CIR) Expert Panel have concluded that Ethylene/Propylene Copolymer is safe for use in cosmetic formulations. The panel noted that the polymer’s large molecular size prevents systemic absorption, and clinical testing indicates it is neither a sensitizer nor a significant irritant. Regulatory bodies, including the SCCS and CosIng, list it without restrictive concentrations, highlighting its high profile of biocompatibility and stability.
Is Ethylene/Propylene Copolymer safe for acne-prone skin?
Yes. This copolymer is non-comedogenic and does not clog pores. Its role is to stabilize the texture of the product rather than interacting with the sebaceous glands.
Is this ingredient considered vegan and cruelty-free?
Ethylene/Propylene Copolymer is 100% synthetic and petrochemically derived. It does not utilize animal-derived raw materials and is compatible with vegan formulations.
Why is this ingredient used in waterproof sunscreens?
The polymer’s hydrophobic properties allow it to form a water-resistant barrier on the skin. This ensures that active UV filters remain in place even after exposure to water or sweat.