Elastic 2-component polyurethane casting compound with excellent electrical and mechanical properties.Due to its high impact strength and good resistance to water, transformer oil, gasoline and other chemicals it is well suited for the insulation of low voltage components as transformers, coils, electronics switches and others.
The casting compound is UL 94 V-0 recognized as self-extinguishing without any halogen or antimony containing flame retardants. It complies with the RoHS (2002/95/EG) and electronic waste regulations (2002/96/EG WEEE directive of the EU).
Stobicast® L 781.36 has been formulated as flame retardant according to the requirements of the Household Appliances standard IEC 60 335 having GWFI of 960°C (glow wire flammability index IEC 60695-2-12) and GWIT of 850 °C (glow wire ignition temperature IEC 60695-2-13).
Typical properties at 25°C
| Polyol | Polyisocyanate | Mixture | |
| Density [g/cm3]DIN 53217/1+2 | 1.48 | 1,22 | 1,42 |
| Viscosity [mPa·s] DIN 53019/1 |
2250 | 100 | 700 |
| Mixing ratio by weight | 100 | 16.0 |
Typical properties of tempered casting resin
(16 hours at 80 °C)
| Mechanical Properties | ||
| Shore Hardness | 70 A | DIN EN ISO 868 |
| Tensile Strength | 4 N/mm2 | DIN 53455 |
| Elongation at break | 130 % | |
| Impact Strength | 33 kJ/m2 | DIN 53453 |
| Water absorption (Disc 50x50x4 mm) |
36 mg in 24 h 63 mg in 96 h |
DIN 53495 |
| Thermomechanical Properties | ||
| Linear Thermal Expansion Coefficient | 125 10-6 K-1 | DIN 53752 |
| Thermal Conductivity |
0.7 W K-1m -1 |
DIN 52612 |
| Glass Transition Temperature | 0°C | DSC |
| Temperature range of Use (for typical Application) |
-40°C / +130°C | |
| Electrical Properties | ||
| Dielectrical Strength | 26 kV/mm | IEC 243 |
| Surface Resistivity | 10^14 Ω | IEC 93 |
| Spec. Current Flow at 20 °C | 10^14 Ω cm | IEC 93 |
| Electrolytic Corrosion | A / 1.2 | VDE 0303/6 |
| Dissipationfactor tan δ ⋅10-2 50 Hz (23/50/80°C) | 5.5 / 7.5 / 8.0 | IEC 250 |
| Dielectric Constant 50 Hz (23/50/80°C) | 4.2 / 5.3 / 7.1 | IEC 250 |
| UL Approval (UL File E 302173) | ||
| Relative Temperature Index RTI (mechanical) |
130°C | UL 746 B |
| Flammability | V-0 @ 3 mm V-2 @ 1,5 mm |
UL 94 |
| Glow Wire Ignition Temperature (GWIT) | 850 °C @ 3 mm | IEC 60695-2-13 |
| Glow Wire Flammability Index (GWFI) | 960 °C @ 3 mm | IEC 60695-2-12 |
| Hot Wire Ignition HWI | 0 | UL 746 A |
| Hot Arc Ignition HAI | 0 | UL 746 A |
| Comparative Tracking Index CTI | 0 / CTI 600 M | UL 746 A / IEC 112 |