BLS 531

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BLS 531 (1843-05-6) is an ultraviolet light absorber (UVA) of the benzophenone class, imparting good light stability for plastics and other organic polymers.  Due to its highly effective broad UV absorption properties and excellent polymer compatibility, BLS 531 offers maximum polymer protection and low color contribution, retards yellowing and loss of physical properties


Chemical Name:                     2-Hydroxy-4-n-Octoxybenzophenone

CAS Number:                         1843-05-6

Chemical Structure:

BLS 531


Typical Properties         

Product Form:                         Solid

Melting Point:                          46.5-49oC

Molecular Weight:                   326 g/mol


BLS 531 is useful for the light stabilization of plastics, including polyolefins (polypropylene, polyethylene, EVA), flexible PVC, acrylics, linear and unsaturated polyesters, polycarbonates, and others. Specialty applications include adhesives, sealants, and in coatings with moderate weatherability requirements. Combinations of BLS 531 with HALS show synergistic performance and are recommended in polyethylene and EVA agricultural films as well as in polypropylene and HDPE thick section applications.


  • Highly compatible with a wide range of organic substrates
  • Low color contribution
  • Particularly suitable for thick films, typically > 100 um and thick sections
  • Low migration rates reduce danger of blooming
  • Low volatility
  • Compatibility with other stabilizers
  • FDA cleared for use in polyolefins and petroluem wax

Guidelines for Use

Typical recommended use levels in plastic applications range between 0.1% and 0.7%. Combinations with other light stabilizers such as HALS and benzoates often show enhanced performance. The exact formulation to be used is dependent on the substrate, performance requirements, and other factors, and should be determined by the user based on testing to simulate actual conditions of use. Please contact Mayzo for specific recommendations.


This product may be stored up to two years in a sealed container. Containers should be kept tightly closed when not in use and stored in a cool, dry place.


Please consult the Safety Data Sheet (SDS) prior to handling or using this product.

FDA Regulations

BLS 531 has been cleared for use in olefin polymers under 21 CFR §178.2010 and in petroleum wax under 21 CFR §178.3710. Please contact your Mayzo representative for complete details, including restrictions of use.

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