What Is Polyurethane-6?
Polyurethane-6 is a man-made copolymer created by linking together several smaller building blocks, including isophthalic acid, adipic acid, hexylene glycol, neopentyl glycol, dimethylolpropanoic acid, isophorone diisocyanate and bis-ethylaminoisobutyl-dimethicone. When these units react they form long chains that behave like a flexible plastic, yet can dissolve in water or alcohol for use in beauty formulas. The ingredient traces its roots to the broader family of polyurethanes first developed in the 1930s as lightweight foams and coatings; chemists later tailored versions like Polyurethane-6 to meet the safety and performance needs of personal care. Production starts with precise mixing of the acids and glycols, followed by the addition of the diisocyanate under controlled heat. The dimethicone-based piece is blended in last to improve spreadability and shine. After curing and purification the result is a fine powder or viscous liquid ready for cosmetic labs.
You will most often see Polyurethane-6 in styling gels, hair sprays, mascaras, liquid eyeliners and long-wear foundations. Its clear, flexible film helps products stay put, resist smudging and feel comfortable on skin or hair.
Polyurethane-6’s Cosmetic Benefits/Uses
Polyurethane-6 brings several practical perks to modern formulas
- Binding: Acts like a glue that holds pigments, shimmer and other solid particles together so they stay evenly mixed and do not settle at the bottom of the bottle
- Film Forming: Creates a thin invisible layer on skin or hair that locks in color, boosts water resistance and gives a smooth touch without stiffness
- Hair Fixing: Provides flexible hold that keeps hairstyles in place while still allowing movement and brushability, reducing flakes compared with traditional hairsprays
Who Can Use Polyurethane-6
Polyurethane-6 suits most skin types including oily, combination, normal and dry because it forms an inert film on the surface instead of penetrating deeply. Sensitive or eczema-prone skin generally tolerates it as well since the polymer lacks fragrance and known sensitizers, though anyone with a past allergy to synthetic resins should be cautious.
This ingredient is fully synthetic with no animal-derived components so it is compatible with vegan and vegetarian lifestyles.
No data link Polyurethane-6 to developmental or lactation risks when used topically. Still, this is not medical advice and pregnant or breastfeeding individuals should run any skincare or haircare product past their doctor to be safe.
Polyurethane-6 does not cause photosensitivity and can be worn under or over sunscreen without affecting UV protection. It also plays nicely with common actives like vitamin C, niacinamide and AHA/BHAs.
Potential Side Effects/Adverse Reactions
Side effects from topical Polyurethane-6 vary by individual. The following are potential, yet uncommon, reactions and most users will not experience them when the ingredient is properly formulated.
- Mild skin redness or itching
- Transient eye or scalp stinging if spray mist or mascara gets into eyes
- Contact allergy presenting as a small rash or hives in people already sensitized to polyurethane compounds
- Product build-up on hair leading to dullness or weighed-down strands if not shampooed out regularly
If a negative reaction occurs discontinue use and consult a healthcare professional.
Comedogenic Rating
Rating: 1 / 5
Polyurethane-6 is a large, water-dispersible polymer that sits on the surface of skin rather than sinking into pores, so it has a very low tendency to trap oil or debris. It contains no fatty acids or heavy waxes that typically raise clogging risk, which is why formulators often use it in long-wear makeup without seeing a spike in breakouts.
Because of this low score, the ingredient is generally considered suitable for acne-prone or breakout-prone users.
Keep in mind that overall pore-clogging potential depends on the full formula, not just one ingredient, so the finished product’s texture and other additives also matter.
Summary
Polyurethane-6 is valued for three main jobs: it binds pigments and particles so formulas stay uniform, it forms a flexible clear film that locks color in place and boosts water resistance, and it offers gentle hair holding power that resists flaking. The polymer chain’s balanced mix of rigid and silicone-like segments lets it stretch, grip and shine all at once, which is why it shows up in everything from mascaras to styling sprays.
While not as famous as silicones or acrylates, Polyurethane-6 enjoys steady popularity among chemists who need reliable long-wear performance with a light feel. Its safety profile is favorable because it is non-sensitizing, non-phototoxic and minimally comedogenic when formulated correctly. Still, everyone’s skin is unique, so patch testing a new product that contains Polyurethane-6 is a smart way to confirm compatibility before full use.