ISO-PUR® K762
Universal low-viscosity PUR casting resin for 1 KV cable joints up to 10 kV.
Training required
Cable joint cast with certified low-viscosity 1 kV casting resin ISO-PUR® K762
ISO-PUR® K762 is a mineral-filled, cold-curing 2-component polyurethane casting resin based on hydrophobic polyether, ester polyols and polymeric aromatic diisocyanates. The potting compound is used for potting of electronic and electrical components and especially for potting low-voltage cast resin cable joints. Properties such as hydrophobicity and hydrolysis resistance comply with VDE 0291 / part 2. In terms of its technical properties, ISO-PUR® K762 is similar to ISO-PUR® K760, which is used as a standard material for potting electrical components, but ISO-PUR® K762 has a lower viscosity. Due to its very high hydrophobicity, the compound is excellently suited as moisture protection in the telecommunications sector, in 1kV cast resin cable joints and for sealing many other electronic and electrical components. Samples made of ISO-PUR® K762 show no embrittlement. The compound shows good corrosion protection properties and high adhesion to metal, ceramics and many plastics. ISO-PUR® K762 is RoHS compliant according to EU Directives 2011/65/EU (“RoHS”) and 2015/863/EU (“RoHS III”).
Area of application
Casting of electronic and electrical components of all kinds and in particular for casting low-voltage cable joints.
Technical data
Resin
Colour
Viscosity (25°C; rot.; 1 s-1)
Viscosity (25°C; rot.; 10 s-1)
Density (23oC)
Beige
Approx. 2250 mPas
Approx. 1400 mPas
Approx. 1,25 g/cm³
Hardener
Colour
Viscosity (25°C; rot.; 1 s-1)
Viscosity (25°C; rot.; 10 s-1)
Density (23oC)
Brown
Approx. 130 mPas
Approx. 120 mPas
Approx. 1,23 g/cm³
Mixture
Mixing ratio resin : hardener
Colour
3:1 parts by weight
Beige (other colours on request)
Density (23oC)
Approx. 1,25 g/cm³
Pot life (23°C)
Gel time (23°C)
Approx. 40 min
Approx. 80 min
Mixed viscosity (25°C; rot.; 1 s-1)
Mixed viscosity (25°C; rot.; 10 s-1)
Approx. 1200 mPas
Approx. 850 mPas
Dielectric strength
Approx. 7 kV/mm
Cured product
Mixing ratio resin: hardener
under standard curing condition
3 : 1 parts by weight
(14 days 23°C / 50% relative humidity) unless otherwise stated
Physical structure
Bubble-free, homogeneous
Hardness Shore D
(23°C; 14d RT 50% rel. h.)
Hardness Shore D
(23°C; oven curing: 4hRT + 24h80°C)
Approx. 55
Approx. 57
Glass transition temperature (midset)
Approx. 20°C
Tensile strength (5A specimen)
(2 mm thickness; speed: 10 mm/min; 23°C)
Elongation at break (5A specimen)
(2 mm thickness; speed: 10 mm/min; 23°C)
Approx. 16 N/mm2
Approx. 105%
Tear resistance
(W-specimen; incision; speed: 10 mm/min; 23°C)
Approx. 28 N/mm
Dielectric strength
Approx. 20 kV/mm
Thermal conductivity
Approx. 0,30 W/K×m
Coefficient of thermal expansion
Approx. 180×10-6 K-1
Tracking resistance
KA 3c
Water absorption after 28 days
in water (immersion; 23°C)
Approx. 0,70%
Water vapour permeability
(75% relative humidity; 23°C; 1 mm thickness)
Approx. 7,80×10-7 g/(Tag×mm2)
Storage and transport
Gebinde trocken und luftdicht verschlossen bei 10 – 35°C lagern. Mindestens 12 Monate haltbar in original verschlossenen Gebinden bei genannten Bedingungen. Kurzzeitige Abweichungen bei Transport und Lagerung sind akzeptabel.
Cleaning
To ensure good adhesion of the cast resin the customer should individually test the suitability of the involved surfaces. Possible pre-treatments like cleaning, activation processes (plasma process) etc. should also be taken into account. The contact surfaces should be free of dirt such as dust, grease or water. For cleaning we recommend ISO-RC® Degreaser for wipe degreasing or ISO-RC® Flux-Off + ISO-RC® Spraywash for spray degreasing (available in 400 ml spray cans).
Processing
Stir up the resin container thoroughly before use to remove any possible sedimentation. Weigh the resin and hardener in the desired mixing ratio and mix for 1 – 3 minutes (depending on mixed quantity and processing time). Apply suitable mixing speed in order to ensure complete homogeneous mixing without introducing too many air bubbles into the reaction mass. The ideal processing temperature is 20 – 25°C. In general, curing is delayed at lower temperatures and accelerated at higher temperatures. When using a double chamber bag, empty the corners well and knead for 3 minutes. Before casting a homogeneous mass, free of streaks, must be obtained. Then pour imme-diately and do not scrape the mixing vessel. Air bubbles in the reaction mass can be removed before the end of the potlife by evacuating the material or carefully fanning the surface with a hot air gun. Machine casting is also possible.
The EC safety data sheet provides information on safety-relevant product properties.
Hardener Component: From 24 August 2023, appropriate training must be provided prior to industrial or commercial use.