Impregnation Resins and Varnishes

Dolph’s® offers a wide range of impregnation resins. These products are, specially designed to fulfill the most demanding conditions of the electrical insulation and electronic protection markets. Dolph’s products are available for all common processes:
– VPI – Vacuum Pressure Impregnation
– Trickling and Dip-Roll
– Dipping and Hot-Dipping

Solvent-free resins have been developed over the past 15 years under European environmental regulation initiatives to minimize the level of global organic emissions (IEC 1999/13 CE). Much progress have been made. At the same time, efforts are ongoing to minimize VOC (volatile organic compound) resin content and to eliminate toxicological risks for workers and the environment. The range of solvent-free resins is growing quickly. For example, monomer-free resin solutions and resins containing reactive monomers/oligomers are green and safe and are not considered as volatile organic compound. However, due to their higher viscosity and slightly lower reactivity over solventless resins, they are generally less versatile and are best suited to well-optimized processes and impregnating equipment.

The main advantages of solvent-free varnishes are:

  • Excellent tank stability even at high temperatures
  • No VOCs (volatile organic compound)
  • Low emissions during curing
  • Green labels
  • Outstanding technical properties

Dolph’s® varnishes and resins are integral components of insulating systems for all classes of rotating equipment, motors and generators. These materials provide environmental protection, vibration reduction and, in some cases, additional dielectric strength. The choice of the right material depends on the end-use application.

The product range of water-borne varnishes reflects the efforts of a dedicated team with worldwide experience, true concern for the environment, and substantial safety and technical expertise. A representative solution is our Aqua-Therm® product range, which includes the following attractive features:

  • Easy and safe use
  • Low environmental impact
  • Excellent impregnability
  • Outstanding bonding properties
  • Good overall protection

Solventless resins are very reactive resins with monomers that could be considered to be VOCs. They show outstanding reactivity compared with varnishes and allow very quick penetration and draining due to their low viscosity. Nothing else at this stage can compete with these resins in term of high productivity and minimum process cost. Organic emissions can be substantially minimized through process choice.

The main advantages of solventless varnishes are:

  • Room temperature impregnation
  • Excellent stability at room temperature
  • Very high reactivity
  • Adaptable to any impregnation process or machine
  • Excellent resin film build and slot fill
  • Outstanding technical properties

Solvent-based varnishes are becoming increasingly less popular due to the effects of their solvent content and organic emissions. Nevertheless, due to their excellent tank stability, their versatile processability and typically good technical performance, they will continue to be important in the future.

The main advantages of solvent-based varnishes are:

  • Easy processing
  • Outstanding stability
  • Adaptable to any machine (motors, generators, transformers)
  • Good resin film build
  • Excellent general technical properties
VonRoll Impregnating Resins and Coatings 2022
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