Air – Drying Type Insulating Varnish Based On Shellac

Application/end use of the product

The varnishes can be used as general purpose insulating varnishes for application on the coils/armatures of electric motors, transformers, finishing of components of electric/electronic instruments, manufacture of laminated products (insulators) and also as finishing varnishes for traction motors.

Advantages of the process/products

The drying time of air-drying type varnish is less compared to the commercially available products. Films of the varnish possess increased resistance towards tracking and transformer oil unlike many commercially available varnishes whose films do not possess the above properties. The varnish is semi-synthetic, thus, more eco-friendly compared to purely synthetic resin based varnishes.

Shellac is non-toxic and non-hazardous, the product will be safer compared to the similar products fully based on synthetic resin.

The varnishes can be suitably pigmented, if desired. Films of the pigmented varnish possess all the desired characteristics.

Specifications of the final product (does the product confirm to any standard specifications): IS:10026-1982

Characteristics of the air-drying type insulating varnish

CharacteristicsAir-drying type (SHA64)
Drying time (for air-drying type)Within 60 min
FinishSmooth, non-tacky, glossy, uniform, hard film
Effect of varnish on enamelled wire(pencil hardness)>16 (>6H)
Dielectric strength (kV/mm):
In air
In air after immersion in water for 24hr

Greening of copperDoes not green
Resistance to tracking test as per IS: 10026-1982Passes, showed increased resistance towards tracking
Resistance to transformer oil (visual)Passes
Scratch hardness(g)1500
Specific gravity0.91
Test for flexibility (3 mm mandrel)Passes (8 mm)

The performance of the varnish has been reported to be satisfactory by consumers. Satisfactory performance of the varnish has been reported when applied on the coils of 6.6 kV 330 kW electric motors. Manufacturers of electric motors, transformers, laminated insulated products and also finishing varnish manufacturers can use our air drying shellac based insulating varnish.