New developments in unsaturated polyester resins used for electrical insulation

Over the last several years in the electrical manufacturing industry there has been an increased demand for products that have reduced quantities of volatile organic content (VOC). In response to this demand the types of electrical insulating resins used have shifted from solvent containing resins to solventless type resins. The solventless types include unsaturated polyester resins and epoxy resins. While these products are solventless a certain amount of VOC can be detected. In unsaturated polyester resins this VOC is attributed to the monomer portion of the resin. Although manufacturers have significantly reduced their VOC emissions there is still a push for further reductions. This trend has prompted resin manufacturers to review their resin systems. One of the strategies for lowering VOC emissions in unsaturated polyester resins is the reduction or elimination of the monomer contained in these resins. This paper highlights the development work done to develop one such resin system.