What Is Polyurethane-70?
Polyurethane-70 is a synthetic polymer created in a multi-step process that links together smaller molecular building blocks into a flexible yet durable film-forming material. Production starts with several polyester diols, including copolymers of adipic acid combined with 1,4-butanediol, adipic acid with hexanediol plus neopentyl glycol, and 1,4-butanediol. These diols react with the diisocyanates isophorone diisocyanate and hexamethylene diisocyanate to form a urethane backbone. In the next step this backbone is modified with the sodium salt of N-(2-aminoethyl)-3-aminoethanesulfonic acid, ethylene diamine and diethanolamine, giving the final polymer its water dispersibility and gentle skin feel.
Polyurethane chemistry first gained cosmetic attention in the late 1990s when formulators searched for lightweight flexible film formers that could outperform traditional resins. As manufacturing techniques improved suppliers engineered grades like Polyurethane-70 that disperse easily in water, tolerate a broad pH range and create breathable films, making them well suited for modern skincare and makeup.
Today Polyurethane-70 appears in a variety of leave-on and rinse-off products. It is common in sheet masks, peel-off masks, color cosmetics such as foundations and mascaras, long-wear sunscreens, hair styling creams, anti-aging serums and skin primers where it helps products stay put yet remain comfortable.
Polyurethane-70’s Cosmetic Benefits/Uses
Formulators value Polyurethane-70 for a single key function that can elevate many product types.
As a film forming agent it creates an invisible flexible layer on skin or hair. This film locks in moisture, improves wear time of pigments, enhances water and sweat resistance in sunscreens, provides a smooth blurring finish in primers, supports peel-off action in masks and helps control frizz in styling products. Because the film is breathable and non-tacky users experience lasting benefits without a heavy feel.
Who Can Use Polyurethane-70
Polyurethane-70 is generally suitable for normal, dry, oily and combination skin because its breathable film does not trap excessive oil yet still helps reduce moisture loss. Sensitive skin usually tolerates it well thanks to its low irritation profile, though anyone with a known allergy to polyurethane resins should avoid it.
The polymer is fully synthetic and contains no animal-derived raw materials, so it is typically considered vegan and vegetarian friendly. As always, final confirmation depends on the complete formula and the manufacturer’s sourcing policies.
No data suggest that Polyurethane-70 is harmful during pregnancy or breastfeeding because its large molecular size limits skin penetration. That said this is not medical advice and pregnant or nursing individuals should review any skincare product with their healthcare provider before use.
The ingredient does not make skin more sensitive to sunlight and has no documented impact on photosensitivity. Normal sun protection habits remain important.
Potential Side Effects/Adverse Reactions
Individual responses to topical Polyurethane-70 vary. The points below outline possible but uncommon reactions when the ingredient is used correctly in cosmetic formulations.
- Mild skin irritation – slight redness or stinging can occur in people with very reactive skin
- Contact dermatitis – rare allergic reactions may lead to itching flaking or rash
- Follicular congestion – in heavy formulations the film might trap sebaceous debris on very oily skin contributing to small bumps
- Interaction with potent actives – the film can increase residence time of highly active ingredients which might heighten their irritation potential
If any discomfort or adverse change appears stop using the product and seek professional guidance.
Comedogenic Rating
Rating: 1 / 5. Polyurethane-70 forms a light breathable film that stays on the surface and contains no oily residues that normally clog pores. Most users, including those prone to acne, can wear it without seeing extra breakouts. In very rich formulas its film can hold heavier ingredients against the skin a bit longer which might contribute to congestion on extremely oily skin, but the polymer itself is low risk. A thorough cleanse at the end of the day removes the film and helps keep pores clear.
Summary
Polyurethane-70 is a water-dispersible film former that locks in moisture, boosts pigment wear and adds water resistance while staying flexible and comfortable. These benefits come from its urethane backbone and hydrophilic side groups that let the film grip the surface but still breathe.
The ingredient has carved out a solid place in long-wear makeup, peel-off masks and modern sunscreens, though it flies under the radar for many shoppers compared with buzzier silicones and acrylates.
Current safety data shows a very low risk of irritation or sensitization because the large polymer molecules do not penetrate skin. Still everyone’s skin is different so patch testing a new product that contains Polyurethane-70 is a smart habit to confirm personal tolerance.