ISO-PUR^® K760

Hydrophobic standard casting resin for electronics and electrical engineering.

ISO-PUR® K760

ISO-PUR^® K760 is a mineral-filled, cold-curing 2-component polyurethane casting resin based on polyether and ester polyols as well as polymeric aromatic diisocyanates. The casting compound was tested in accordance with VDE 0291 / Part 2 including hydrophobicity and resistance to hydrolysis. ISO-PUR^® K760 is used as the standard material for potting electrical components. 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. ISO-PUR^® K760 does not contain any plasticizers and does not tend to become brittle. The material shows very little shrinkage during curing. The resin shows good corrosion protection properties and high adhesion to metal, ceramics and many plastics. The standard mixing ratio resin : hardener is 4 : 1 parts by weight (pbw). ISO-PUR^® K760 is RoHS compliant according to EU Directives 2011/65/EU (“RoHS”) and 2015/863/EU (“RoHS III”).

Area of application

Hydrophobic standard casting resin for electronics and electrical engineering.

Technical data

Downloads

Product data sheet Safety data sheet resin Safety data sheet hardener

Resin

Colour

Viscosity (25°C; rot.; 1 s^-1)

Viscosity (25°C; rot.; 10 s^-1)

Density (23°C)

Beige

Approx. 8500 mPas

Approx. 3700 mPas

Approx. 1,43 g/cm³

Hardener

Colour

Viscosity (25°C; rot.; 1 s^-1)

Viscosity (25°C; rot.; 10 s^-1)

Density (23°C)

Brown

Approx. 130 mPas

Approx. 120 mPas

Approx. 1,23 g/cm³

Mixture

Mixing ratio resin : hardener

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Colour

Beige (other colours on request)

Density (23^oC)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 1,37 g/cm³

Approx. 1,38 g/cm³

Approx. 1,39 g/cm³

Approx. 1,40 g/cm³

Pot life (23°C) /

Gel time (23°C)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 8 min / approx. 12 min

Approx. 10 min / approx. 15 min

Approx. 12 min / approx. 18 min

Approx. 13 min / approx. 20 min

Approx. 15 min / approx. 30 min

Approx. 20 min / approx. 40 min

Mixed viscosity (25°C; rot.; 1 s^-1)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 3000 mPas

Approx. 3500 mPas

Approx. 3800 mPas

Approx. 4000 mPas

Approx. 4400 mPas

Approx. 4800 mPas

Mixed viscosity (25°C; rot.; 10 s^-1)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 1500 mPas

Approx. 1800 mPas

Approx. 1900 mPas

Approx. 2000 mPas

Approx. 2200 mPas

Approx. 2400 mPas

Cured product

Under standard curing condition

(14 days 23°C / 50% relative humidity) unless otherwise stated

Hardness Shore A
(23°C; 14d RT 50% rel. h.)

Hardness Shore A
(23°C; Oven curing: 4hRT + 24h80°C)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

> 90 / > 90

Approx. 88 / approx. 87

Approx. 76 / approx. 77

Approx. 62 / approx. 65

Hardness Shore D
(23°C; 14d RT 50% rel. h.)

Hardness Shore D
(23°C; Oven curing: 4hRT + 24h80°C)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 71 / approx. 72

Approx. 64 / approx. 63

Approx. 56 / approx. 55

Approx. 43 / approx. 38

Approx. 26 / approx. 25

Approx. 16 / approx. 17

Long-term temperature resistance /

Short-term temperature resistance

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 140°C / approx. 200°C

Approx. 130°C / approx. 180°C

Approx. 120°C / approx. 180°C

Approx. 110°C / approx. 160°C

Glass transition temperature (midset)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 40°C

Approx. 22°C

Approx. 13°C

Approx. 4°C

Approx. -13°C

Approx. -23°C

Tensile strength (5A specimen)
(2 mm thickness; speed: 10 mm/min; 23°C)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 24 N/mm²

Approx. 17 N/mm²

Approx. 11 N/mm²

Approx. 7 N/mm²

Approx. 3 N/mm²

Approx. 2 N/mm²

Elongation at break (5A specimen)
(2 mm thickness; speed: 10 mm/min; 23°C)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 65%

Approx. 85%

Approx. 100%

Approx. 120%

Approx. 125%

Approx. 135%

Tear resistance
(W-specimen; incision; speed: 10 mm/min; 23°C)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 83 N/mm

Approx. 59 N/mm

Approx. 16 N/mm

Approx. 8 N/mm

Approx. 4 N/mm

Approx. 2 N/mm

Dielectric strength

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 24 kV/mm

Approx. 21 kV/mm

Approx. 20 kV/mm

Approx. 21 kV/mm

Dielectric loss factor tan δ (25°C; 50 Hz)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 0,02

Dielectric constant ε (25°C; 50 Hz)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 4,20

Approx. 4,30

Approx. 4,00

Approx. 4,10

Approx. 4,00

Approx. 4,10

Thermal conductivity

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 0,30 W/K×m

Approx. 0,35 W/K×m

Approx. 0,40 W/K×m

Coefficient of thermal expansion

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 45×10^-6 K^-1

Approx. 50×10^-6 K^-1

Approx. 60×10^-6 K^-1

Approx. 75×10^-6 K^-1

Approx. 110×10^-6 K^-1

Approx. 120×10^-6 K^-1

Tracking resistance

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

KA 3c

Water absorption
After 28 days in water (immersion; 23°C)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 0,50%

Approx. 0,60%

Approx. 0,70%

Approx. 1,30%

Approx. 2,80%

Approx. 4,90%

Water vapour permeability
(75% relative humidity; 23°C; 1 mm thickness)

3 : 1 parts by weight

4 : 1 parts by weight

4,5 : 1 parts by weight

5 : 1 parts by weight

6 : 1 parts by weight

7 : 1 parts by weight

Approx. 6,60×10^-7 g/(day×mm²)

Approx. 7,00×10^-7 g/(day×mm²)

Approx. 7,20×10^-7 g/(day×mm²)

Approx. 9,90×10^-7 g/(day×mm²)

Approx. 1,40×10^-6 g/(day×mm²)

Approx. 1,90×10^-6 g/(day×mm²)

Storage and transport

Store in a dry and airtight, closed container at 10 – 35°C. Can be stored for at least 12 months in original sealed containers under the above conditions. Short-term deviations during trans-port and storage are acceptable.

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 thoroughly and knead for 3 minutes. Before casting, a homogeneous mass, free of streaks, must be obtained. Pour immediately afterwards 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 (containing diisocyanate): As of August 24, 2023, appropriate training must be provided before industrial or commercial use.