UR5641 Optically Clear Flame Retardant Polyurethane

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UR5641 is an optically clear flexible polyurethane resin, with the added bonus of having excellent flame retardant properties. Due to its exceptional properties it makes it suitable for the protection of LED luminaires which are located in hazardous environments. The resin system is based on halogen free aliphatic chemistry ensuring that cured UR5641 is resistant to the yellowing effects of UV light, making it useful in exterior as well as interior applications.


Approvals RoHS Compliant (2015/863/EU): Yes
UL Approval: Meets UL94 V-0
Typical Properties
Liquid Properties: Base Material Polyurethane
Density Part A – Resin (g/ml) 1.12
Density Part B – Hardener (g/ml) 1.15
Part A Viscosity (mPa s @ 23ºC) 1850
Part B Viscosity (mPa s @ 23ºC) 1550
Mixed System Viscosity (mPa s @ 23ºC) 1600
Mix Ratio (Weight) 0.96:1
Mix Ratio (Volume) 1:1
Usable Life (20°C) 12 mins
Gel Time (23°C) 25 mins
Cure Time (23 °C) 24 hours
Cure Time (60 °C) 4 hours
Colour Part A – Resin Clear
Colour Part B – Hardener Clear
Storage Conditions Dry Conditions: Above 5°C, Below 30°C
Shelf Life 9 months
(Measured on a 100ml sample in a cylinder of diameter 49.4mm @ 23°C)
Shrinkage <1%

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