What Is Polyurethane-57?
Polyurethane-57 is a man-made polymer created by reacting different building blocks from the urethane family. Its technical name, “1,3-Dioxolan-2-one, polymer with 1,6-hexanediol, 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane and 1,5-pentanediol, 2-hydroxyethyl acrylate-blocked,” hints at the mix of diols and isocyanates that link together to form a flexible yet sturdy network. This network is then “blocked” with hydroxyethyl acrylate so it stays stable until it is added to a cosmetic formula.
Polyurethanes first found fame in the 1930s as protective coatings and foams. Chemists later noticed that certain versions, like Polyurethane-57, could form thin, invisible films that felt comfortable on skin. As cosmetic labs looked for ways to boost makeup wear time and improve texture in the 1990s and 2000s, these film-forming grades of polyurethane made their way into primers, foundations and skin treatments.
The production process starts with carefully measuring the diols and isocyanates, reacting them under heat, then stopping (or blocking) any leftover reactive spots with hydroxyethyl acrylate. The finished polymer is usually supplied as a liquid dispersion or fine powder that blends easily into water-based or solvent-based cosmetic bases.
You will most often spot Polyurethane-57 in long-wear foundations, liquid eyeliners, mascara, peel-off masks, transfer-resistant lip color, setting sprays and some anti-aging serums where a flexible film can smooth the look of fine lines.
Polyurethane-57’s Cosmetic Benefits/Uses
In beauty formulas Polyurethane-57 plays one key role that brings several payoffs for both the product and the user.
Binding: This polymer helps ingredients stick together and stay put on skin or hair. By forming a light, elastic film it keeps pigments evenly dispersed, boosts wear time, reduces flaking and gives products a smooth, flexible finish that moves with facial expressions.
Who Can Use Polyurethane-57
Polyurethane-57 is generally well tolerated by most skin types, including normal, oily, combination and dry. Sensitive skin usually does fine with it too because the polymer sits on top of the skin instead of sinking in, reducing the chance of irritation. Exceptionally reactive or allergy-prone skin should still proceed with caution since any film-forming agent can occasionally trap heat or sweat and trigger redness.
The ingredient is synthetic and contains no animal-derived components, so it is considered suitable for both vegans and vegetarians.
Current research shows no evidence that Polyurethane-57 poses a special risk to women who are pregnant or breastfeeding. That said this is not medical advice and anyone expecting or nursing should run any skincare product past a qualified health professional just to be safe.
Polyurethane-57 does not increase photosensitivity, so it will not make skin more prone to sunburn. Standard daytime sun protection is still recommended for overall skin health.
Potential Side Effects/Adverse Reactions
Responses to topical Polyurethane-57 vary from person to person. The points below list potential issues but most users will not experience them when the ingredient is used correctly in a well-formulated product.
- Mild skin irritation such as light redness or itching, usually short-lived
- Contact dermatitis in people who are allergic to urethane-based polymers
- Acne flare-up in very acne-prone users if the film traps excess oil and debris
- Eye stinging if a product like mascara or eyeliner migrates into the eye before it fully sets
If any discomfort or reaction occurs discontinue use and consult a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1/5
Polyurethane-57 forms a thin breathable film that is lightweight and not oily so it rarely clogs pores. Still, any film former can trap extra sebum or sweat in very oily skin which is why it does not get a perfect zero. Overall it is considered suitable for people prone to acne or breakouts, especially when used in well balanced formulas that rinse off easily.
No well documented interactions with common acne medications or treatments have been reported.
Summary
Polyurethane-57 is mainly a binder that keeps pigments and other ingredients stuck together and attached to skin or hair. By laying down a flexible film it improves wear time, cuts flaking, boosts color payoff and leaves a smooth finish that moves with facial expressions.
It is not as famous as silicone elastomers or vinyl polymers but it has a loyal following in long wear makeup and peel off masks where lasting power matters.
Current data shows it is low risk for irritation, has very low comedogenicity and is fine for most skin types including sensitive skin. As with any new cosmetic ingredient a quick patch test is smart before adding a product with Polyurethane-57 to your daily routine.