Bomar Oligomer Product
UV/EB Oligomer


BR-641D: Difunctional Aliphatic Polybutadiene Urethane Acrylate Oligomer

BR-641D is a Polybutadiene (PBD) urethane acrylate, which was designed to meet rigorous electronic coating applications. This oligomer has exceptional adhesion to various metals,
glass, and polycarbonate substrates. BR-641D has many desirable properties that are typical to PBD resins, combined with radiation curability. In applications requiring thermal cycling resistance, BR-641D withstands the extremes of temperature typical of such tests, without undue degradation of properties. In addition to the adhesion properties listed in the table below, BR-641D showed excellent adhesion to PMMA, ABS, PVC, Nylon-6, Polystyrene, and Polypropylene.

Neat Properties
Property Value
Viscosity cP (60ºC) 15,000
Pt-Co (APHA) Color 26
Refractive Index (25ºC) 1.48
Density, g/cm3 (25ºC) 0.93
Monomer Dilution Properties
Property I30 I50 TM50 TP50 H50 HE30
Tensile Strength (MPa [psi]) 4.8 [700] 7.6 [1100]
Elongation (%) 300 400
Elastic Modulus (MPa [ksi]) 1.4 [0.2] 2.1 [0.3]
Durometer Hardness 85A 54D
Water Absorption (%) 24hrs 0.06 0.06
MEK Double Rubs (#) 60 40
Viscosity (cP) 12,000 @ 25ºC 1,600 @ 25ºC ‖ @ 25ºC ‖ @ 25ºC ‖ @ 25ºC ‖ @ 25ºC

** Tensile Properties per ASTM D882   - Not Tested   || Incompatible   X Unable to Measure


  • Excellent hydrophobic properties
  • Acid/base resistance
  • Excellent elongation
  • Low water absorption
  • Low-temperature flexibility
  • Excellent dielectric properties
  • Outstanding adhesion
  • Thermal cycling capability


  • Electronics coatings
  • Potting compounds
  • Electronics adhesives
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