UV-531 Benzophenone UV Absorber (Octabenzone)

UV-531 (octabenzone, CAS 1843-05-6, formula C21H26O3) is a 2-hydroxybenzophenone UV absorber used to protect polyolefins, PVC, adhesives, and coatings from sunlight. It absorbs ultraviolet light and releases the energy as low-level heat, which slows the yellowing, chalking, and loss of strength that sunlight causes in unprotected polymers. RawSource supplies UV-531 in bulk against your grade and volume.

RawSource supplies UV-531 as a technical benzophenone UV absorber comparable to Cyasorb UV-531 (Syensqo) and Chimassorb 81 and Uvinul M 408 (BASF). RawSource is an independent distributor and is not affiliated with, endorsed by, or sponsored by the brand owners; the brand names are used only to identify the comparable commercial grade.

UV-531 is one of the most widely used benzophenone absorbers because it is low in cost, compatible with common polyolefins, and effective in film and molded parts. It is often paired with a hindered-amine light stabilizer (HALS), which mops up the radicals that form once some UV gets through, so the two additives protect the polymer by different mechanisms.

Applications

Polyolefin film and molded parts

In polyethylene and polypropylene, including agricultural and packaging film, UV-531 screens ultraviolet light that would otherwise break chains and make the part brittle. It is compounded into the resin so protection is distributed through the wall of the part.

PVC, ABS, and styrenics

In PVC profile, sheet, and in ABS and styrenic parts, UV-531 helps hold color and gloss under outdoor exposure. It is chosen where a benzophenone absorber gives adequate protection at a favorable cost point.

Coatings and adhesives

In coatings and pressure-sensitive adhesives, UV-531 absorbs ultraviolet light in the film, protecting both the binder and the substrate underneath. It is used where the formulation tolerates a benzophenone-class absorber.

Host polymers and typical use

UV-531 is dispersed into the polymer or coating during compounding or formulation, where it absorbs ultraviolet light before it can break polymer chains, fade pigments, or dull the surface. The systems below are where UV-531 is most often specified.

Typical use levels for polymer UV absorbers fall in the 0.1 to 1.0 percent range, set by part thickness, expected outdoor exposure, and the co-stabilizer package (commonly a hindered-amine light stabilizer). Confirm loading on the bench and the exact specification on the Certificate of Analysis for each lot.

Handling and regulatory status

UV-531 is an industrial additive for plastics and coatings and is not sold for cosmetic or food use unless a grade is specified for that. It can be classified as a skin sensitizer, and benzophenone UV absorbers are under regulatory review for endocrine activity as a chemical class, so follow the Safety Data Sheet for the exact classification and handling.

Bulk UV-531 Supply from RawSource

RawSource supplies UV-531 benzophenone UV absorber in bulk to coatings, plastics, and polymer compounding buyers and their purchasing teams. We source to your target grade, purity, and physical form across domestic and import channels, so we match specification, lead time, and landed cost to your program. Multiple qualified producers make UV-531 to a common identity, which keeps supply competitive and available on demand.

Every lot ships with a Certificate of Analysis (CoA) and the current Safety Data Sheet (SDS). We source to order rather than carry fixed stock, so pricing and availability are confirmed by quote. Send your grade, annual volume, and any specification limits for a current bulk price.

Request a bulk UV-531 quote

To buy UV-531 in bulk from RawSource, send your target grade, physical form, packaging, destination, and any specification requirement, and we return a current bulk quote. A CoA and SDS accompany every shipment. Request a quote to get started.