Use of expandable epoxy systems for barrier materials in high voltage liquid-filled transformers

A barrier component for a liquid-filled transformer prepared by

• a) producing a foamable resin system by blending, in the presence of at least one blowing agent,
• b) at least one polyglycidyl compound;
• and
• ii) at least one curing agent for the polyglycidyl;
• b) applying a first and second layer of the foamable resin system onto each major surface of a first substrate layer to produce a laminated structure;
• and
• c) subjecting the laminated structure to heat and pressure as the first and second layer of the foamable resin system react.

A method for manufacturing a barrier component for a liquid-filled transformer comprising:

• a) blending
• (i) at least one polyglycidyl compound;
• and
• (ii) at least one curing agent for the polyglycidyl compound in the presence of at least one blowing agent to produce a foamable resin system;
• b) applying a first layer and second layer of the foamable resin system onto each major surface of a first substrate layer to produce a laminated structure;
• c) subjecting the laminated structure to heat and pressure as the first and second layer of the foamable resin system react.

A method for manufacturing a high voltage liquid-filled transformer comprising:

• a) blending
• (i) at least one polyglycidyl compound;
• and
• (ii) at least one curing agent for the polyglycidyl compound in the presence of at least one blowing agent to produce a foamable resin system;
• b) applying a first layer and second layer of the foamable resin system onto each major surface of a first substrate layer to produce a laminated structure;
• c) subjecting the laminated structure to heat and pressure as the first and second layer of the foamable resin system react;
• d) fitting the laminated structure into the housing;
• and
• e) impregnating the fitted laminated structure with a dielectric liquid.