What Is Polyurethane-77?
Polyurethane-77 is a man-made polymer created through a two-step process. First Methyl Ricinoleate, a derivative of castor oil, reacts with Propanediol to form a flexible polyester. This fresh polyester is then linked with 1,10-Decanediol and Isophorone Diisocyanate, yielding a resilient polyurethane network known as Polyurethane-77. The result is a smooth film-forming material that behaves like a liquid plastic in water-based formulas yet dries to a soft breathable layer on skin.
The cosmetic industry started exploring specialty polyurethanes in the late 1990s when chemists looked for safer alternatives to thick, heavy carbomer gels. Polyurethane-77 gained popularity because it offers consistent texture, is stable across a wide pH range and pairs well with modern clean-beauty preservatives. Current manufacturing uses large stainless reactors where temperature and mixing speed are tightly controlled to keep by-products low and purity high.
In finished products you will most often find Polyurethane-77 in lightweight moisturizers, gel creams, sheet mask essences, sunscreen lotions, hair styling creams and long-wear makeup bases. It is chosen when formulators want a silky feel without greasiness and need dependable viscosity that will not break down in a hot bathroom or a cold purse.
Polyurethane-77’s Cosmetic Benefits/Uses
Polyurethane-77 serves a single yet crucial role in personal care formulas: it controls viscosity. By thickening water-based mixtures it keeps creams from separating, suspends pigments in makeup and lets gels cling to skin long enough to deliver active ingredients. Because it forms an invisible film, it also enhances spreadability and can give products a soft focus finish without leaving a tacky residue.
Who Can Use Polyurethane-77
Polyurethane-77 is generally well tolerated across normal, dry, oily and combination skin because it is non occlusive and free of common irritants like fragrance or alcohol. Sensitive or eczema-prone users usually do fine with it but should keep an eye on how their skin responds since any film-forming polymer can occasionally trap heat or sweat in very reactive skin.
The ingredient is plant derived for the most part and synthesized in a lab without animal inputs so it is suitable for vegan and vegetarian lifestyles. As always finished products may contain other animal-based ingredients so a label check is still necessary.
The polymer’s large molecular size means it does not penetrate deeply, which is why it is considered low risk for women who are pregnant or breastfeeding. This is not medical advice and anyone expecting or nursing should clear every new skincare product with a doctor first.
Polyurethane-77 does not cause photosensitivity and has no known interactions with sunscreen actives, exfoliating acids or retinoids. It is also odorless so it will not conflict with fragrances added by the brand.
Potential Side Effects/Adverse Reactions
Responses to topical Polyurethane-77 can vary from person to person. The points below describe potential issues but most users will not experience them when the ingredient is formulated and used correctly.
- Mild skin irritation such as redness or itching in very sensitive individuals
- Contact dermatitis triggered by residual isocyanate traces in exceptionally reactive skin
- Eye stinging or watering if the product migrates into the eye area before it dries
- Build-up or pilling on the skin when layered with heavy silicones or oils
- Dry feeling or tightness if used in high concentrations without accompanying emollients
If any uncomfortable reaction occurs stop using the product and consult a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1 / 5
Polyurethane-77 earns a low score because its large polymer chains sit on the surface without seeping into follicles and it leaves behind a light breathable film rather than an oily residue that can block pores. It is not metabolized by skin bacteria and does not oxidize into pore-clogging by-products. Only in very heavy formulations layered with rich oils could it theoretically contribute to congestion.
This makes Polyurethane-77 generally suitable for acne-prone or breakout-prone skin.
As with any film former, thorough cleansing at the end of the day helps prevent buildup that could trap dead skin cells over time.
Summary
Polyurethane-77 is primarily a viscosity controller that thickens and stabilizes water-based cosmetics while adding a silky slip. Its film-forming nature suspends pigments evenly, keeps emulsions from separating and leaves skin with a soft focus finish that feels weightless.
The ingredient enjoys steady but niche popularity among formulators who want an alternative to carbomers or heavier gums. You will mostly spot it in modern gel creams, sunscreens and long-wear makeup rather than old-school lotions.
Safety profiles show a very low risk of irritation or sensitization so most users can incorporate it confidently. Still, everyone’s skin is unique so performing a simple patch test when trying a new product containing Polyurethane-77 is a smart precaution.