Knowde Enhanced TDS
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Features & Benefits
Applications & Uses
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- Application Method
- Applications
Insulator Coatings
- Application Details
Protective silicone coating for porcelain, glass and epoxy insulators as well as for other high-voltage insulating equipment where surface contamination causes service problems. POWERSIL® 552 BROWNGREEN forms a long-term hydrophobic surface. Thus it prevents the formation of wet conductive films and therefore the risk of pollution flashovers. It contains ATH as filler.
- Processing
Surface pretreatment
The insulator surface to be coated should be clean and free of dust and grease. For cleaning the following operations are suggested:
- Proper cleaning by using water and a suitable detergent might be sufficient,
- Insulators that show an adhering pollution, such like cement, other mineral or chemical pollution layers should be cleaned by either “cob corn-“ or carbon dioxide blasting,
- Any type of grease or fatty pollution is to be removed by using a suitable solvent like White Spirit or turpentine,
- Residual contaminants should be removed by thoroughly wiping,
- Finish the cleaning just before spraying POWERSIL® 552 BROWNGREEN with Isopropanol or an equivalent alcohol.
Check carefully that there is no residue of dirt or grease left before spraying! In most cases it is not necessary to apply a primer before coating. Proper shaking of drum is mandatory before material is used.
Coating Application
- POWERSIL® 552 BROWNGREEN is preferably applied by spraying. It can be applied by brushing or dipping as well. For spraying application, the airless process was found to be efficient. The following equipment settings were found to be suitable:
- Flat nozzle of 0.33 mm, 20°
- Settings of pressure output 50 - 150 bar
- The spray gun should be moved evenly across the surface at a distance of about 30 - 50 cm. Due to the thixotropic properties of POWERSIL® 552 BROWNGREEN it is usually possible to apply the first layer with a good cover.
- A second layer can be applied after approximately 10-20 minutes. A typical dry film thickness is 0.4 mm to 0.5 mm. Thus, the theoretical consumption is 0.7 kg to 0.9 kg of POWERSIL® 552 BROWNGREEN per square meter of insulator surface.
- Take losses for overspray and cleaning of the equipment into consideration. Rain can damage the coating. In case of rain, please protect the job site or stop application. Full cure is obtained in 8 - 12 hours after coating application depending on thickness, temperature and humidity.
- Curing of the coating releases by-products that lead to the formation of siloxanes. These may condensate at the surface, especially at low temperature and low ventilation rate. Therefore it is recommended to process the coating at a temperature above 20°C at well ventilated conditions. All spraying equipment should be cleaned with a nonpolar solvent (e. g. Xylene or White Spirit) immediately after use.
Maintenance
The product contains migratable matter that is able to encapsulate contaminants and to provide a hydrophobic surface. Coated insulators may appear dirty after some time in service. Nevertheless, washing and cleaning, especially with detergents and other chemicals is not recommended. In case of necessity of any cleaning, we recommend to use POWERSIL® Shine.
Inspection
The water repellent appearance can be evaluated by spraying with water. IEC 62073. A partly lowering of the effect does not necessarily require immediate action. Experience shows that the remaining parts of the insulator will provide the necessary insulation ability. Physical damage, such like scratching can be easily repaired by brushing of fresh coating after partly cleaning with White Spirit. To allow an instant replacement of broken insulators it is recommendable to store a number of coated spare insulators. These should be stored in a protective covering.
Properties
- Cured Properties
- Uncured Properties
- Properties
- Very good resistance to weathering
- Outstanding tracking resistance
- Note
Cured Properties: Cure conditions: 14d / 23°C / 50% RH.
| Value | Units | Test Method / Conditions | |
| Arc Resistance | 420 | seconds | IEC 61621 |
| Density (at 23°C) | 1.41 | g/cm³ | DIN EN ISO 1183-1 A |
| Dielectric Strength (1mm sheet) | 28 | kV/mm | IEC 60243-1 |
| Dissipation Factor (tan δ, at 50Hz) | 1x10⁻³ | — | IEC 62631-2-1 |
| Elongation (at break) | 100 | % | ISO 37 Type 1 |
| Permittivity (at 50Hz) | 2.9 | — | IEC 62631-2-1 |
| Shore Hardness A | 68 | — | DIN ISO 48-4 |
| Tensile Strength | 3 | N/mm² | ISO 37 Type 1 |
| Tracking Resistance | 1A 4.5 | — | IEC 60587 |
| Volume Resistivity | 5 x 10¹⁵ | Ohm-cm | IEC 62631-3-1 |
| Value | Units | Test Method / Conditions | |
| Density (at 23°C) | 1.11 | g/cm³ | DIN EN ISO 2811-2 |
| Dynamic Viscosity (at 25°C, Shear rate 10 s⁻¹) | 3000 | mPa·s | DIN EN ISO 3219 |
| Flash Point | 19 | °C | ISO 13736 |
| Skin Formating Time (at 23°C, 50% r.h) | 9 | minutes | — |
Packaging & Availability
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