What Is Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer?
Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer is a man-made polymer created by linking together small units of poly(1,4-butanediol) and isophorone diisocyanate, then finishing the chain with hydroxyethyl acrylate. All three building blocks are produced in modern chemical plants from widely available petrochemical feedstocks, so the final ingredient is fully synthetic and not taken from plants or animals. Chemists began exploring this type of polymer in the late 1990s while searching for film formers that were clear, flexible and resistant to water. After safety testing it started to appear in cosmetic labs in the early 2000s and has since become a favorite for products that need staying power without a heavy feel.
Manufacturing involves a carefully controlled step-growth reaction. First, poly(1,4-butanediol) reacts with isophorone diisocyanate to build a backbone with urethane links. Hydroxyethyl acrylate is then added to cap the chain with acrylate groups that help the finished polymer spread evenly and cure into a smooth film. The process takes place in closed reactors with precise temperature and pH control to keep the molecular weight within a narrow range, giving consistent performance batch after batch.
Because the polymer forms a clear flexible film, you will find it in a wide variety of cosmetics. Long-wear foundations, primers, BB creams, sunscreens, liquid lipsticks, mascaras and brow gels rely on it to boost durability. It is also common in sheet masks, peel-off masks, anti-aging serums and lightweight moisturizers where it locks in actives while leaving a soft finish. Hair styling sprays and gels sometimes use it to give hold without stiffness.
Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer’s Cosmetic Benefits/Uses
This ingredient is prized for one key function that delivers several practical benefits in everyday products.
Film forming: When applied to skin or hair the polymer spreads out then dries into an invisible flexible layer. This film helps makeup resist sweat and humidity, keeps sunscreens in place longer, traps moisture so skin feels smoother and reduces transfer of pigments onto clothes or masks. Because the film is breathable it avoids the tight plastic feel older film formers sometimes caused, giving a comfortable finish suitable for daily wear.
Who Can Use Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer
This film former is generally well tolerated by all skin types. Oily and combination skin appreciate its weightless feel that does not add extra grease while dry skin benefits from the moisture-locking barrier it creates. Even sensitive skin can usually use it because the polymer stays on the surface and has very low reactivity, though a small number of people who react to many synthetic ingredients may still notice redness or itching.
The ingredient is produced entirely from petroleum-derived feedstocks with no animal inputs so it is suitable for vegetarians and vegans. Most manufacturers also avoid animal testing in line with current cosmetic regulations but consumers who follow a strict cruelty-free lifestyle should still check the brand’s overall policy.
No studies have flagged safety concerns for pregnant or breastfeeding women because the large polymer molecules do not penetrate deeply and are not absorbed into the bloodstream. That said this is not medical advice and anyone who is expecting or nursing should review new products with a doctor to be sure they fit their individual health plan.
Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer does not make skin more sensitive to sunlight and can be worn during the day without increasing the risk of sunburn. It is also fragrance-free and non-volatile so it is unlikely to trigger headaches in scent-sensitive users.
Potential Side Effects/Adverse Reactions
Responses to topical use of Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer can differ from person to person. The effects listed below are only possibilities and, when the ingredient is used correctly in a finished product, most people will not notice any trouble.
- Mild skin irritation – a small number of users may feel itching or see slight redness, especially if their skin barrier is already compromised
- Allergic contact dermatitis – very rare sensitivity to trace residual monomers or stabilizers can cause a rash or swelling
- Eye irritation – if mascara or spray products containing the polymer get into the eyes they may sting until rinsed out with clean water
- Tight or dry feeling – the flexible film can occasionally make skin feel a bit tight particularly in low humidity or when layered with many mattifying products
If any unwanted reaction occurs stop using the product and seek advice from a dermatologist or healthcare provider.
Comedogenic Rating
Rating: 0 / 5
Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer earns a zero because its large synthetic molecules stay on the skin surface, contain no greasy oils or waxes, and are not metabolized into pore-clogging by-products. It forms an airy film that lets skin breathe rather than sealing follicles shut, so it has virtually no track record of provoking blackheads or breakouts.
That makes it a green-light ingredient for people who struggle with acne or congestion, though the overall formula and other ingredients still matter.
Summary
Bis-Hydroxyethyl Acrylate Poly(1,4-Butanediol)-9/Ipdi Copolymer is mainly valued as a lightweight film former that dries into a clear flexible layer. This film boosts makeup wear time, keeps sunscreens in place, locks in moisture and reduces product transfer while remaining comfortable and breathable.
The polymer is fairly popular in long-wear foundations, mascaras, brow gels and certain skincare masks yet it is not a household name since brands rarely spotlight film formers on the front label. Behind the scenes formulators appreciate its reliable performance and ease of use.
Safety studies show very low irritation and virtually no systemic absorption, so most users can apply it with confidence. As with any new cosmetic though it is smart to patch test first to make sure your individual skin stays happy.