SynChem – Resins & Varnishes WEVOSIL 26040 FL
Solvent-free, two-component silicone-based gap filler with high thermal conductivity .
The resulting soft-elastic moulding material is characterized by good low-temperature flexibility and excellent behaviour in the temperature shock test. The system contains mineral fillers, which can be abrasive.
Recommended temperature range: -60 °C to +200 °C.
The resin is processed together with WEVOSIL 26040 FL B.
Application
- Pressure-sensitive electrical components
- Complete assemblies in SMD technology
- Thermally conductive adhesive and encapsulation
Standards
- Temperature application range -60 °C - +200 °C
Delivery forms
30 kg containers
Color
WEVOSIL 26040 FL A: Natural
WEVOSIL 26040 FL B: Blue
Storage
Polymer (A-component) and crosslinker (B-component) must be stored dry and at a temperature of 5 °C to 30 °C and not in the open air. The containers should be stored upright and not
directly on the cold floor (floor temperature not below 5 °C). WEVOSIL 26040 has a shelf life of 6 months after production.
At temperatures above 25 °C, the settling of the fillers contained in the casting compound is accelerated. The potting compound is then more difficult to homogenize.
Hardening
- Pot life: 50-70 minutes at room temperature, depending on layer thickness and casting volume.
- Curing time: 4 hours at room temperature, or 1 hour at 100 °C
- Final chemical curing: several days at room temperature
Curing notes:
- Excessive humidity has a damaging effect on the uncured compound. If necessary, curing should take place in an air-conditioned room, a container with low humidity or in an oven.
- Curing at an elevated temperature (50 - 100°C) accelerates the curing reaction and can influence the adhesion of the potting compound to the walls of the component.
- The WEVOSIL 26040 FL casting compound reaches its final hardness after a few days at room temperature.
- After approx. 4 hours curing at room temperature (or 1 h @ 100 °C) approx. 90 - 95 % of the curing takes place. To achieve the final hardness, post-curing can then be carried out for 2 hours at 165 - 180 °C. However, this last step is not absolutely necessary. After a few days, the casting compound reaches its final hardness even at room temperature (depending on the system).
- Electrical tests of the component quality can usually be carried out after the first curing (4 hours at room temperature or 1 h @ 100 °C).
Protection
Our products are intended exclusively for industrial use. For further details, please read the safety data sheet.
Processing
Our processing instructions please find here.
Technical data
| Property | Unit of measure | Condition | Value | Test method |
|---|---|---|---|---|
| Mixing ratio | Gew-% | 100:100 | ||
| Pot lilfe | min | 25 °C | 50-70 | |
| Curing time | h | 25 °C | 4 | |
| Curing time | h | 100 °C | 1 |
| Property | Unit of measure | Condition | Value | Test method |
|---|---|---|---|---|
| Density | g/cm³ | WEVOSIL 26040 FL A | 3.08-3.12 | |
| Density | g/cm³ | WEVOSIL 26040 FL B | 3.08-3.12 | |
| Viscosity | mPas | WEVOSIL 26040 FL B / 22 °C | 100,000-150,000 | |
| Viscosity | mPas | 22 °C, WEVOSIL 26040 FL A | 100,000-150,000 | |
| Mixture viscosity | 22 °C | 100,000-150,000 | ||
| Hardness | Shore 00 | 60-80 | ISO 48-4 | |
| Water absorption | % | 30 d, RT | 0.1 | |
| Elongation at break | % | 30 | ISO 527-2 |
| Property | Unit of measure | Condition | Value | Test method |
|---|---|---|---|---|
| Glass transition temperature | °C | -100 | TMA | |
| Thermal conductivity | W/m*K | 4.0 | ISO 22007-2:2008 |
| Property | Unit of measure | Condition | Value | Test method |
|---|---|---|---|---|
| Dielectric strength | kV/mm | >20 | DIN EN 60243 | |
| Dielectric constant ε at 50 Hz, 23 °C | 7.0 | DIN EN 60250 | ||
| Dielectric constant; at 1 kHz, 23 °C | 6.78 | DIN EN 60250 | ||
| Dielectric constant ε at 1 MHz, 23 °C | 6.51 | DIN EN 60250 | ||
| Volume resistance specific at 23 °C, 50 % r.h. | Ωxcm | >10^13 | DIN EN 62631-3-1:2016 | |
| Surface resistivity at 23°C and 50 % r.h. | Ω | >10^14 | DIN EN 62631-3-2:2016 |