WACKER® Primer G 791 A/B
WACKER® Primer G 791 A/B is a two-component, addition-curing primering system that is diluted in an organic solvent. The primer is applied to the substrate, and upon curing, it forms a primer film that firmly adheres to the substrate. Subsequently, applying a silicone rubber onto the primed substrate and undergoing vulcanization will create a tight bond between the silicone rubber and the substrate.
Product families
Applications
- Power Transmission & Distribution
Product Families
- Primers & Sealers
Other characteristics
- Brand
- WACKER
- Features
- Excellent Substrate Adhesion, Good Adhesion
- Product Type
2K (2 component) Coating, Primer, Solventborne Coating; 2K (2 component) Coating; Primer; Solventborne Coating
- Application Area
- Wires
- Compatible Substrates & Surfaces
- Elastomers & Rubbers
- Carrier
- Solvent-based
- Markets
- Electrical & Electronics
- Properties
- Silicone on silicone curing
- Cure
- Chemical Cure
- Safety Note
Due to its high content of organic solvent, WACKER® PRIMER G 791 A/B is subject to the same safety regulations as these i.e., it is a flammable liquid. Appropriate precautions are an absolute must.
- Technology
- Ready-to-Use Products
- Specific Features
- Adhesion promoting primer
- Application Details
Surfaces to be primed have to be dry and free from grease, oil, wax, dust, rust or other contaminants. Also mold-release agent from the previous vulcanization cycle on the silicone rubber substrate has to be removed.; The surface should be cleaned, e.g. with a non-polar solvent such as mineral spirits (boiling range between 80 °C and 140 °C), followed by a polar solvent, such as acetone. Very smooth surfaces may be roughened by grinding until the shine of the surface disappears. Loose particles must be removed.; Components A and B must be homogenized before use. A and B are mixed in a ratio of 1:1 by weight. The pot life of the catalyzed primer mixture is 2 – 3 days at room temperature and can be prolonged by cooling to approx. 1 week at 6 °C. Storage must be in properly sealed containers.; Wacker Primer G 791 A/B [1.0] is applied in a thin film layer with a brush, by dipping or spraying. The primer film has to be vulcanized for 20 – 60 minutes at 100 – 120 °C.; The silicone rubber should be applied to the primed surface soon after the heating process, if possible. It is recommended that this is done not later than approximately 2 days after priming the substrate. Otherwise a drop in adhesive strength may occur. Prior to the application of the silicone rubber, the primed surface has to be kept free of contaminations.; Note: Initial adhesion directly after vulcanization of the rubber will in many cases be high already. In some cases, however, initial adhesion will be sufficient for handling the composite while maximum adhesive strength will only be achieved after about 4 days. Additional post curing of the cured rubber at 70 °C – 150 °C will further improve adhesion. Once opened, containers of WACKER® PRIMER G 791 A/B should be kept well sealed and stored in a cool and dry place.
Technical data
Table 1 of 2
1 row| Characteristic | Value | Unit |
|---|---|---|
| Active Substance (A+B) | approx. 20 | wt % |
Table 2 of 2
8 rows| Characteristic | Value | Unit | Method |
|---|---|---|---|
| Density (at 23°C, Componenet A) | 0.77 | g/cm³ | DIN 51757 |
| Density (at 23°C, Componenet B) | 0.73 | g/cm³ | DIN 51757 |
| Dynamic Viscosity (Component A, at 23°C) | 4000 | mPa·s | Brookfield |
| Dynamic Viscosity (Component B, at 23°C) | 85 | mPa·s | Brookfield |
| Flash Point (Component A) | -4 | °C | ISO 13736 |
| Flash Point (Component B) | 3 | °C | ISO 13736 |
| Ignition Temperature (liquids) (A) | 391 | °C | EN 14522 |
| Ignition Temperature (liquids) (B) | 378 | °C | EN 14522 |
