Wire Enamel Insulating Varnish for Magnet Wire Applications

Wire enamel insulating varnish is a specialized coating applied to copper or aluminum conductors, cured to form a thin, durable insulating film, commonly uses in electrical components like motors, transformers, and coils.

Performances

Wire enamel insulating varnish provides electrical insulation, protecting the wire from short circuits and corrosion, and also enhances the wire’s mechanical strength and thermal stability. The enamel is typically a modified polyester with a polyamide overcoat.

Benefits

Wire enamel Coating bridge electrical safety, thermal management, and environmental demands. Innovations in polymer chemistry and application precision continue to expand their role in electrification technologies, particularly in renewable energy and e-mobility sectors. Copper wire enamel is popular product.

Wire enamel types

Polyesterimide

Base	PROPERTIES	RECOMMENDED FOR WIRE SIZE (mm DIA)	CLASS OF WIRE	CUT THROUGH FOR 2 Min AT °C	HEAT SHOCK AT 200 °c/30 Min	TANGENT DELTA VALUE °C
THEIC Polyesterimide	Improved Adherence for aluminium wire	0.2-5.0	200	340	2d	180-200
THEIC Polyesterimide	Excellent heat shock and high peel (UL approved File no E326858)	0.05-5.0	180	340	2d	185-210
Polyesterimide	Excellent adhesion and suitable for rectangular conductor	Upto 60 sq.mm rect.	155	260	4d	150-170
THEIC Polyesterimide	Excellent heat shock and suitable for rectangular conductor	1.6-5.0 mm Dia & Upto 60 sq.mm rect.	200	320	2d	190-210
THEIC Polyesterimide	Suitable for high speed enameling machines upto 200 VD	0.05-5.0	200	340	2d	195-210

Polyamide

Base	PROPERTIES	RECOMMENDED FOR WIRE SIZE (mm DIA)	CLASS OF WIRE	CUT THROUGH FOR 2 Min AT °C	HEAT SHOCK AT 250 °c/30 Min	TANGENT DELTA VALUE °C
Modified Polyamide	It’s very good replacement of traditional polyamide-imide wire enamel and its cresol soluble and free from NMP so application made easy	0.05-1.6	200	360	1d	190-210
Polyamide-Imide	Hermetic resistance, low coefficient of friction	0.05-1.6	200	360	1d	190-210

Modified Polyamide-Imide

Base	PROPERTIES	RECOMMENDED FOR WIRE SIZE (mm DIA)	CLASS OF WIRE	CUT THROUGH FOR 2 Min AT °C	HEAT SHOCK AT 280 °c/30 Min	TANGENT DELTA VALUE °C
Modified Polyamide – imide	Good adherence on thick gauges. Excellent hermetic resistance, low coefficient of friction & can be used as sole coat	1.6-5.0 mm Dia & Upto 60 sq.mm rect.	220	360	1d	160-170

Polyurethane

Base	PROPERTIES	RECOMMENDED FOR WIRE SIZE (mm DIA)	CLASS OF WIRE	CUT THROUGH FOR 2 Min AT °C	HEAT SHOCK AT 180 °c/30 Min	TANGENT DELTA VALUE °C
Polyurethane	Fast solderability & good cut through.	0.04-1.8	155	240	2d	145-165
Polyurethane	Fast solderability & good cut through	0.04-1.8	155	220	2d	135-155
Polyurethane	High cut through,good solderability & resistance to Styrented impregnating resins.	0.04-2.5	180	260	1d	175-185

Polyester

Base	PROPERTIES	RECOMMENDED FOR WIRE SIZE (mm DIA)	CLASS OF WIRE	CUT THROUGH FOR 2 Min AT °C	HEAT SHOCK AT 180 °c/30 Min	TANGENT DELTA VALUE °C
Polyester	High processing speed & high peel value	0.2-5.0	130	240	5d	100-115
THEIC Modified Polyester	High processing speed, high cut through and heat shock	0.05-5.0	155	340	2d	120-130
Modified Polyester	Excellent heat shock	0.05-5.0	155	320	2d	145-165

Polyvinyl Formal

Base	PROPERTIES	RECOMMENDED FOR WIRE SIZE (mm DIA)	CLASS OF WIRE	CUT THROUGH FOR 2 Min AT °C	HEAT SHOCK AT 180 °c/30 Min	TANGENT DELTA VALUE °C
Polyvinyl Formal	Excellent mechanical properties with transformer oil resistance (UL approved File No. E326858)	0.5-5 mm Dia & upto 40 sq.mm rect.	105	220	1d	95-115
Polyvinyl Formal	Specially Formulated for CTC	0.5-5 mm Dia & upto 40 sq.mm rect.	120	220	1d	130-140

Wire enamel Coating includes PUR, PEI, PAI and PVF, temperature indices: 105°C (standard) to 220°C. PUR has Solderable and self-bonding, anti-pinhole performance. Magnet wire adpots these wire enamels with insulation resistance widely used for transformer & motor windings.