Bomar Oligomer Product
UV/EB Oligomer

BR-640D

BR-640D: Difunctional Aliphatic Polybutadiene Urethane Acrylate Oligomer

BR-640D is a polybutadiene (PBD) urethane acrylate with a functionality of two. Designed to meet rigorous electronic applications, BR-640D has many desirable properties typical to PBD resins, combined with radiation curability. In applications requiring thermal cycling resistance, BR-640D withstands the extremes of temperature typical of such tests, without undue degradation of properties. Excellent hydrophobic properties exhibited where 0.012 and 0.037% water was absorbed by cured coating when submerged in water for 24 hours. In addition to the adhesion properties listed in the table below, BR-640D showed excellent adhesion to ABS, acrylic, nylon-6, PVC, and PS.

Neat Properties
Property Value
Viscosity cP (60ºC) 5,000
Pt-Co (APHA) Color 15
Refractive Index (25ºC) 1.48
Density, g/cm3 (25ºC) 0.94
Monomer Dilution Properties
Value
Property I30 I50 TM50 TP50 H50 HE30
Durometer Hardness 76A 45D 66D 45D
Elastic Modulus (GPa [ksi]) 1.9 [0.27] 4.5 [0.65] 241.3 [35] 11.7 [1.7]
Elongation (%) 190 190 10 60
MEK Double Rubs (#) 65 9 >200 10
Tensile Strength (MPa [psi]) 3.4 [500] 5.5 [800] 9.0 [1300] 3.4 [500]
Water Absorption (%) 24hrs 0.01 0.04 0.09 0.85
Viscosity (cP) 15,000 @ 25ºC 1,500 @ 25ºC ‖ @ 25ºC ‖ @ 25ºC 60 @ 25ºC 9,900 @ 25ºC

Features

  • Excellent hydrophobicity
  • Low water absorption
  • Excellent dielectric properties
  • Acid/Base resistance
  • Low temperature flexibility
  • Thermal cycling capabilities

Applications

  • Electronics coatings and adhesives
  • Potting compounds
  • Water vapor barrier coatings
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