Bomar Oligomer Product
UV/EB Oligomer

BR-643

BR-643: Difunctional Aliphatic Polybutadiene Urethane Acrylate Oligomer

BR-643 is a polybutadiene (PBD) urethane acrylate. Designed to meet rigorous electronic applications, BR-643 has many desirable properties typical to PBD resins, combined with radiation curability. In applications requiring thermal cycling resistance, BR-643 withstands the extremes of temperature typical of such tests, without undue degradation of properties.

Neat Properties
Property Value
Viscosity cP (60ºC) 17,000
Pt-Co (APHA) Color 50
Refractive Index (25ºC) 1.508
Density, g/cm3 (25ºC) 0.95
Monomer Dilution Properties
Value
Property I30 I50 TM50 TP50 H50 HE30
Durometer Hardness 84A 58D ? 69D 76D
Elastic Modulus (GPa [ksi]) 53.1 [7.7] 551.6 [80] ? 275.8 [40] 448.2 [65]
Elongation (%) 55 65 ? 25 3
MEK Double Rubs (#) 10 7 ? 40 >200
Tensile Strength (MPa [psi]) 7.6 [1100] 18.6 [2700] ? 13.8 [2000] 10.3 [1500]
Water Absorption (%) 24hrs 0.04 0.03 ?
Viscosity (cP) 19,000 @ 25ºC 2,100 @ 25ºC ? @ 25ºC 2,300 @ 25ºC 900 @ 25ºC — @ 25ºC

Features

  • Excellent hydrophobic properties
  • Acid/base resistance
  • Curable with radiation
  • Improves adhesion
  • Low-temperature flexibility
  • Excellent dielectric properties
  • Exhibits hydrolytic stability
  • Low water absorption

Applications

  • Coatings for electronics
  • Potting compounds
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