What Is Polyurethane-99?
Polyurethane-99 is a synthetic polymer created through a multistep process that starts with common building blocks found in industrial chemistry. First Succinic Acid reacts with 1,4-Butanediol and Neopentyl Glycol to form an ester polyol. This intermediate is then combined with Saturated Methylene Diphenyl Diisocyanate, giving the backbone of a polyurethane. To make the material friendly to water-based cosmetic formulas, chemists extend the chain with the sodium salt of 2-((2-aminoethyl)amino ethanesulfonic acid along with Ethylenediamine. The result is a high-performance film former that can disperse smoothly in water without relying on heavy solvents.
Polyurethane materials first appeared in the 1930s as replacements for rubber and varnishes. As scientists refined the chemistry they discovered that certain grades could create flexible, breathable films on skin and hair. By the early 2000s water-dispersible versions like Polyurethane-99 became attractive to cosmetic formulators seeking light textures that still deliver staying power.
Today you will find Polyurethane-99 in a range of beauty products. It is common in long-wear foundations, smudge-resistant mascaras, peel-off face masks, color cosmetics that promise transfer resistance, hair styling creams and body lotions that aim to leave a smooth protective veil.
Polyurethane-99’s Cosmetic Benefits/Uses
In skincare and makeup formulas Polyurethane-99 serves one key purpose that brings several practical benefits.
Film forming: Once the product spreads on skin or hair the polymer links together into a thin flexible layer. This invisible film locks pigments in place, helps active ingredients stay where they are needed and provides resistance to water, sweat and rubbing. Because the film is breathable it avoids the heavy or sticky feel some traditional fixatives can leave behind, making it popular for all-day wear products and lightweight moisturizers alike.
Who Can Use Polyurethane-99
Polyurethane-99 is generally well tolerated by most skin types, from oily to dry and even sensitive skin. Its lightweight breathable film rarely traps excess oil or moisture so it tends not to aggravate acne or flaking. People with a history of polymer allergies or very reactive skin should still pay extra attention when trying a new product that contains it, as any synthetic film former can occasionally cause irritation.
The polymer is produced entirely from petrochemical or mineral sources, with no animal-derived feedstocks or by-products. This makes it suitable for both vegetarians and vegans as long as the finished cosmetic has not been tested on animals, something that varies by brand and region.
Current data show no specific reproductive or developmental hazards linked to topical use of Polyurethane-99. Pregnant or breastfeeding users can typically use products that feature it, but this is not medical advice. Anyone who is expecting or nursing should still review all skincare products with their doctor to be extra safe.
Polyurethane-99 is not known to cause photosensitivity. It will not make skin more prone to sunburn or interfere with sunscreen actives. It also has no documented interactions with common skincare ingredients such as retinoids, vitamin C or hydroxy acids, so it can fit into most routines without special timing.
Potential Side Effects/Adverse Reactions
Individual responses to topical Polyurethane-99 can differ. The following points list potential side effects that have been reported in rare cases. When the ingredient is formulated correctly most users experience none of these issues.
- Mild skin irritation temporary redness or itching, usually resolves after product removal
- Contact dermatitis localized rash or inflammation in people sensitive to certain polymers or residual monomers
- Eye stinging or watering if the product migrates into the eyes, most often with mascaras or eyeliners
- Follicular congestion occasional clogged pores in very acne-prone skin when used in heavy layers or with occlusive products
- Allergic reaction rare cases of swelling or hives that require prompt medical attention
If any negative reaction occurs stop using the product immediately and seek guidance from a healthcare professional.
Comedogenic Rating
Rating: 1/5
Lab and in-use data show Polyurethane-99 forms a thin breathable film that lets sweat and sebum escape instead of sealing them in. Its molecules are large and stay on the surface rather than sinking into pores, so it has very low clogging potential. A few people with highly oil-rich skin have reported minor congestion when they layer it with heavy occlusive products, which is why the rating is not a perfect zero.
Overall this ingredient is considered suitable for acne-prone or breakout-prone skin.
Because the polymer is often paired with silicones, waxes or rich emollients in long wear makeup, the finished product’s overall pore-clogging risk can be higher than the polymer alone. Check the full ingredient list if you are extremely sensitive to buildup.
Summary
Polyurethane-99 is mainly used for film forming, creating a flexible water-resistant layer that keeps pigments in place, boosts wear time and shields skin or hair without a heavy feel. It achieves this by linking its polymer chains together as the formula dries, producing an even micro-thin coat that moves with the surface beneath it.
The ingredient enjoys steady popularity in long wear foundations, stay-put eye makeup and lightweight lotions though it is less common in minimalist or all-natural lines.
Current safety data indicate a low risk of irritation or sensitization for most users. Still, everyone’s skin is unique so it is smart to patch test any new product that contains Polyurethane-99 before applying it widely.