What Is Polyurethane-98?
Polyurethane-98 is a man-made polymer created through a series of controlled chemical reactions. It begins with two liquid building blocks called diols. One is formed when 1,2-butylene oxide reacts with propylene glycol, while the other comes from combining adipic acid and isophthalic acid with 3-methylpentane-1,5-diol. These two pieces are blended then joined to a small but highly reactive molecule known as trimethylhexamethylene diisocyanate. Last, hydroxyethyl acrylamide is added to “cap” the ends and lock the structure in place, giving the final product its stability and performance.
This type of polyurethane first appeared in specialty coatings in the late 1990s. Chemists noticed it formed flexible, durable films that resisted chipping and water, qualities that soon caught the attention of cosmetic formulators. Today Polyurethane-98 is most at home in nail polishes and nail strengtheners, though it may also show up in liquid eyeliners, brow gels and certain long-wear makeup bases where a clear, tough yet comfortable film is needed.
Polyurethane-98’s Cosmetic Benefits/Uses
In beauty formulas Polyurethane-98 offers two main advantages:
- Binding – It helps all the other ingredients in a product stick together and stay evenly spread on the surface of the nail or skin. This gives smoother application, better wear time and less cracking or peeling.
- Nail conditioning – The thin flexible film it forms adds a protective coat over the nail plate. This shields nails from water and everyday wear, helping them feel stronger and look glossier over time.
Who Can Use Polyurethane-98
Because Polyurethane-98 sits on the surface and forms an inert film, it is generally well tolerated by dry, normal, oily and sensitive skin types. Those with an established allergy to polyurethane resins or acrylates should avoid it, as even trace contact could trigger redness or itching.
The ingredient is fully synthetic and contains no animal by-products, making it suitable for both vegans and vegetarians provided the finished formula carries the same cruelty-free standards.
No studies point to systemic absorption from topical use, so products with Polyurethane-98 are not expected to pose a risk during pregnancy or breastfeeding. This is not medical advice and anyone who is pregnant or nursing should clear all personal care products with a doctor first.
Polyurethane-98 does not increase photosensitivity, meaning it will not make skin more prone to sunburn. It also plays well with common cosmetic actives such as retinol or vitamin C, so routine layering should not cause issues.
Potential Side Effects/Adverse Reactions
Side effects from topical Polyurethane-98 vary from person to person. The points below cover possible reactions, though most users experience none of them when products are properly formulated and used as directed.
- Contact dermatitis – Rare cases of redness, itching or rash in those allergic to polyurethane or acrylate chemistries
- Eye irritation – Stinging or watering if liquid product accidentally gets into the eyes before it dries
- Mild respiratory discomfort – Temporary throat or nasal irritation from inhaling solvent fumes during application of some nail lacquers
- Nail brittleness – Repeated use alongside harsh removers may leave nails feeling dry or fragile
If any of these reactions occur stop using the product and consult a healthcare professional or pharmacist for guidance.
Comedogenic Rating
Rating: 0/5 (non-comedogenic). Polyurethane-98 is a large inert polymer that forms a surface film rather than sinking into pores and it contains no oily or waxy residues that could block follicles. Its molecular size keeps it sitting on top of the skin where it can be washed away easily.
This makes it suitable for people who are prone to acne or frequent breakouts.
Very heavy, multilayer use without proper cleansing could trap existing sebum and debris, so remove long-wear products thoroughly at day’s end.
Summary
Polyurethane-98 works mainly as a binder and nail conditioner. It links other ingredients together then dries into a clear flexible film that helps polish stay smooth, chip resistant and glossy while adding a protective coat over the nail plate.
The polymer sees steady but niche use, most often in high-performance nail lacquers or budge-proof eye products where a tough yet comfortable film is needed. It is less common in everyday skincare so casual users may not notice it on many labels.
Safety data show a very low risk of irritation or allergy for the majority of people. Still, individual sensitivities exist so it is wise to patch test any new product containing Polyurethane-98 before full application.