EPOXYLITE E478
Harmonization Code : 3910.00.00.90 | Silicones in Primary Forms; Others
Main features
- One-Component Thixotropic VPI Processing
- Class 180 Insulation-System Use
- Medium-Voltage Motor Impregnation
Product Description
EPOXYLITE E478 Thixo Epoxy VPI Resin is a one-component, heat-cured, 100% solids thixotropic epoxy for vacuum pressure impregnation of medium-voltage motors and generators. The resin has a typical viscosity of 1,500 to 3,000 cP at 25 deg C and 20 rpm, supporting controlled retention during VPI processing. stated cure options are six hours at 149 deg C or four hours at 163 deg C. The cured material has typical Shore D hardness of 85 and is used in recognized insulation systems through Class 180. Applications include uncatalyzed tape systems and random-wound motors below 7 kV.
Key features
- One-component thixotropic processing: The 100% solids resin is supplied ready for heat-cure VPI processing.
- Controlled VPI viscosity: Typical viscosity is 1,500 to 3,000 cP at 25 deg C and 20 rpm.
- Class 180 insulation-system use: The product is documented in recognized insulation systems through Class 180.
Applications
- Vacuum pressure impregnation of medium-voltage motors
- Vacuum pressure impregnation of generators below 7 kV
- Uncatalyzed tape systems
- Random-wound motors
TDS, SDS & Technical Documents
Technical Specifications
Physical Properties
Viscosity
1500-3000 mPa.s
Viscosity is a measurement of a fluid’s resistance to flow.
Viscosity is commonly measured in centiPoise (cP). One cP is defined as
the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP.
A product like honey would have a much higher viscosity -around 10,000 cPs-
compared to water. As a result, honey would flow much slower out of a tipped glass than
water would.
The viscosity of a material can be decreased with an increase in temperature in
order to better suit an application
Thermal Properties
Flash Point
94 °C
The flashpoint of a solvent is the lowest possible temperature at which it can vaporize to form an ignitable vapor.
Flashpoint is often confused with “autoignition temperature”, which is the temperature at which a solvent ignites without an ignition source.
Glass Transition Temperature (Tg)
92 °C
The glass transition temperature for organic adhesives is a temperature region where the polymers change from glassy and brittle to soft and rubbery. Increasing the temperature further continues the softening process as the viscosity drops too. Temperatures between the glass transition temperature and below the decomposition point of the adhesive are the best region for bonding.
The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs.
General Properties
Film Thickness
50-100 µm
Film thickness is the thickness of a backing film without taking into account any coatings or adhesive layers. It is measured in micron and the conversion factor to mil is 0.039.
Electrical Properties
Dielectric Strength
151 kV/mm
Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material.
Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property.
As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow.
Volume Resistivity
> 1 x 10^16 Ohms⋅cm
Volume resistivity, also called volume resistance, bulk resistance or bulk resistivity is a thickness dependent measurement of the resistivity of a material perpendicular to the plane of the surface.
Additional Information
Technical properties
As-supplied / before-processing properties
Typical as-supplied values for the one-component thixotropic VPI resin.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Product form | One-component thixotropic resin | - | As supplied |
| Solids content | 100 | % | As supplied |
| Viscosity | 1,500 to 3,000 | cP | At 25 deg C and 20 rpm |
| Weight per gallon | 9.4 to 9.8 | lb/gal | As supplied |
Technical properties
After-processing / final-state properties
Final-state values retain the stated cure and insulation-system scope.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Cure schedule | 6 h at 149 deg C; 4 h at 163 deg C | - | Heat-cure options |
| Shore D hardness | 85 | - | Typical cured value |
| Insulation-system class | Up to Class 180 | - | UL-recognized systems; exact system scope applies |
