What Is Polyurethane-36?
Polyurethane-36 is a fully synthetic film-forming polymer created by linking PPG-17 with isophorone diisocyanate and dimethylol propionic acid, then neutralizing the mix with triethylamine while water is present. A final step with hydrazine lengthens the chains and fine-tunes the texture. This chemistry places Polyurethane-36 in the family of water-dispersible polyurethanes, materials first explored in the mid 20th century for industrial coatings and later adapted for cosmetics when formulators noticed their flexible, weightless feel on skin and hair. Today the ingredient is produced in closed reactors where temperature and pH are carefully controlled to guide each reaction, after which the finished polymer is filtered and blended into an aqueous dispersion ready for cosmetic use.
Because it dries to a thin yet durable film, Polyurethane-36 appears in many long-wear beauty products. You will commonly find it in mascaras and liquid eyeliners that need smudge resistance, long-lasting foundations and BB creams, transfer-proof lip colors, peel-off or leave-on face masks, sprayable sunscreens, hair styling gels and even certain nail treatments that aim for a breathable finish.
Polyurethane-36’s Cosmetic Benefits/Uses
Its single role in formulas is film forming, meaning it spreads into a uniform layer that holds makeup pigments in place, boosts water resistance, reduces flaking and gives products a smooth flexible finish that moves with the skin or hair without feeling tight.
Who Can Use Polyurethane-36
Polyurethane-36 is generally considered suitable for most skin types, including oily, dry, combination and normal skin, because it sits on the surface and does not react with sebum or natural moisture. Extremely sensitive or eczema-prone skin may find any film former uncomfortable if the product is layered too thickly, as the resulting seal can trap heat and sweat which might aggravate redness or itch.
The polymer is produced entirely from petroleum-derived or laboratory-made feedstocks so it contains no animal matter. For that reason products using Polyurethane-36 are normally acceptable to both vegans and vegetarians unless other ingredients in the same formula come from animal sources.
Current data show that large synthetic polymers like Polyurethane-36 have minimal skin penetration and are not absorbed into the bloodstream. Pregnant or breastfeeding women can therefore use cosmetics containing it within normal usage limits, but this is not medical advice and anyone expecting or nursing should confirm all personal care choices with a healthcare professional.
Polyurethane-36 is not known to cause photosensitivity and does not interfere with sunscreen filters. It is also widely used around the eyes in mascaras and eyeliners, indicating a good safety record for that delicate area when products are properly formulated.
Potential Side Effects/Adverse Reactions
Responses to topical Polyurethane-36 can vary from person to person. The effects listed below are possible yet uncommon when the ingredient is used as intended by reputable manufacturers. Most users will not experience any problems.
- Mild skin irritation – a tingling or burning sensation shortly after application, usually resolving once the product is removed
- Contact dermatitis – redness, itching or rash in individuals allergic to one of the polymer’s building blocks or residual processing agents
- Tight or dry feeling – the film may reduce normal skin respiration in very dry environments leading to temporary discomfort
- Eye irritation – flakes or particles from dried products like mascara can bother the eyes if they break off and enter the tear film
- Clogged pores – unlikely but possible if heavy layers are left on overnight especially on acne-prone areas
If any of the above reactions occur stop using the product and consult a qualified medical professional.
Comedogenic Rating
Polyurethane-36 has a comedogenic rating of 1 out of 5. The polymer molecules are large and primarily stay on the very top of the skin, so they cannot easily slip into pores and start the clogging process. That said, any film former can trap sweat, sebum or other ingredients underneath if applied in very heavy layers or not removed at the end of the day, which is why the rating is not a perfect zero. In practical use the ingredient is acceptable for people who are prone to acne or breakouts, provided the final product is removed thoroughly with a gentle cleanser. Users who already struggle with congestion might want to avoid sleeping in thick, long-wear formulas that contain several film formers in combination.
Summary
Polyurethane-36’s main job is to create a smooth flexible film that locks makeup pigments in place, boosts water and smudge resistance and gives products a lightweight feel that moves with skin or hair instead of cracking. It does this by forming a continuous network as the water in the formula evaporates, leaving behind an elastic layer that grips to the surface yet remains breathable enough for comfortable wear.
The ingredient is popular in long-wear mascaras, eyeliners, foundations, lip colors, peel-off masks and certain hair styling products, though it is still less widespread than older film formers like acrylates because it costs more to make and requires careful pH control during production.
Current safety data and its large molecular size suggest little to no skin penetration, with irritation or allergy being uncommon. As with any cosmetic ingredient, individual sensitivities vary so it is always smart to perform a small patch test when trying a new product that features Polyurethane-36.