CAS 2035-72-5 Reactive Benzophenone UV Absorber Monomer (UV724 / BHPMA) — Eliminate Migration & Blooming, Enable Long-Term Weathering & Anti-Yellowing for UV Curable Systems

With the rapid development of UV curing industry towards outdoor application, optical grade, low extractable and food-contact compliance, conventional small-molecule UV absorbers face a well-known technical bottleneck. They are only physically blended inside resin matrix. Under thermal cycling, humidity fluctuation, long-term UV exposure and solvent contact, these additives easily migrate to coating surface, bloom, precipitate or volatilize. Gradual loss of UV protection leads to fast yellowing, gloss reduction, chalking and cracking. Blooming also causes haze, odor and surface contamination, which blocks the application in optical film, food packaging and medical coating sectors.

CAS 2035-72-5, 2-Hydroxy-4-(methacryloyloxy)benzophenone (BHPMA, UV724), is a copolymerizable functional monomer integrating benzophenone UV chromophore and methacrylate reactive double bond. Different from additive light stabilizers, it delivers permanent UV protection via covalent bonding into crosslinked polymer network.

It appears as white to pale yellow crystalline powder, commercial purity ≥98% or ≥99% (GC). Melting point: 77–79℃, predicted boiling point: 437.4℃, density: 1.219 g/cm³. Insoluble in water, freely soluble in acetone, ethyl acetate, toluene and common acrylic reactive diluents. It has excellent compatibility with urethane acrylate, epoxy acrylate and other UV oligomers. It will not induce haze or turbidity for clear coatings and retains high transmittance, ideal for optical-grade requirements. MEHQ inhibitor (~3000ppm) is added to prevent premature self-polymerization during storage. Within recommended dosage range, it has minor influence on curing speed, easy to substitute into existing formulations.

Its anti-aging mechanism relies on ESIPT (Excited State Intramolecular Proton Transfer). The intramolecular hydrogen bond between ortho-hydroxyl and carbonyl absorbs UVA/UVB from 280–360 nm, and converts harmful UV energy into harmless heat non-radiatively, suppressing photo-oxidative chain scission and yellowing. The methacrylate double bond copolymerizes with acrylic monomers/oligomers during UV or thermal radical curing, chemically anchored into polymer network. No free residual small molecule remains after cure, which fundamentally prevents migration, blooming, solvent extraction and thermal volatilization, delivering persistent weather resistance. Meanwhile, the benzophenone moiety can act as hydrogen abstraction photoactive group to assist surface curing in selected systems.

Recommended loading level is 0.5–3.0 wt%. It can be used alone or synergistically combined with HALS and other UV absorbers to achieve superior performance in QUV and xenon accelerated aging tests. Pre-formulation screening on blooming, aging and compatibility is suggested for each system.

Typical Application Segments

*Outdoor UV coatings: wood varnish, plastic hard coat, architectural UV finish, long-term exterior protection

*Optical film hardcoat: PET / PC / PMMA protective film, display substrate coating, high-transparency anti-yellowing layer

*UV inks & overprint varnish: food-contact compliant overprint lacquer, flexible packaging printing ink, low migration requirement

*UV adhesive: lamination adhesive, flexible film bonding adhesive, avoid interface contamination from migrated additives

*Photopolymer resin for 3D printing & precision lithography, stabilize dimension and suppress yellowing

*Specialty substrates: medical UV coating, ophthalmic materials and composite impregnation requiring low extractables

We supply this product with stable commercial production and consistent batch-to-batch quality. COA is available for each lot, including GC/HPLC, moisture, melting point and transmittance data. Sample, pilot and bulk orders are acceptable. Our technical team supports formulation recommendation, aging benchmarking and compliance documentation.

Storage instruction: Keep tightly sealed, store in cool, dry and dark warehouse, away from heat, direct sunlight and strong oxidants to avoid self-polymerization. Operate in accordance with SDS.

As a premium reactive light stabilizer, CAS 2035-72-5 (UV724) is an ideal drop-in upgrade for traditional benzophenone absorbers, widely adopted in outdoor, optical and low-migration UV formulations, helping manufacturers solve blooming, migration and aging pain points and develop durable, compliant UV curable products.

Product Info

CAS No.: 2035-72-5

Chemical Name: 2-Hydroxy-4-(methacryloyloxy)benzophenone

Alias: 4-Benzoyl-3-hydroxyphenyl methacrylate, BHPMA, UV724

Formula: C17H14O4

MW: 282.29