Arcwire PI 240 Polyimide Wire Enamel
Polyimide enamel applied from polyamic acid solution and built from one chemistry through the whole pass sequence, for class 240 winding wire. The film holds its electrical strength at temperature and resists most solvents.
Grade Arcwire PI 240 | Range Electrical Insulation and Wire Enamels | Technology Polyimide, supplied as polyamic acid solution in organic solvent
Technical Data Sheet
Arcwire PI 240
Issue 2026.09
1. Product description
A polyimide enamel for the highest thermal class in the range, built from one chemistry through the whole pass sequence, for windings that run at a continuous conductor temperature beyond the reach of polyesterimide and polyamide-imide, and for short-term overload, cryogenic and chemically exposed duty. The film holds its electrical strength at temperature and resists most solvents, but it is not solderable and it is attacked by strong alkali and by prolonged hydrolysis. Where the slot is tight and abrasion during pull-in is the limiting factor, it is overcoated with a polyamide-imide topcoat rather than used bare.
2. Features
- Class 240, the upper end of the range
- Single chemistry through all passes, imidised in the oven
- Holds electrical strength at temperature and resists most solvents
- For short-term overload, cryogenic and chemically exposed duty
- Attacked by strong alkali and prolonged hydrolysis; not solderable
3. Recommended uses
Winding wire for machines and coils that run at a continuous conductor temperature beyond polyesterimide and polyamide-imide, and for short-term overload, cryogenic and chemically exposed duty. Overcoated with a polyamide-imide topcoat where the slot is tight and abrasion during pull-in is the limiting factor.
Substrates. Bare round and rectangular copper conductor, including silver and nickel plated copper for the highest temperature work.
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Polyimide, supplied as polyamic acid solution in organic solvent | Formulation |
| Appearance | Clear liquid, amber to brown | Visual inspection |
| Non-volatile matter | Low solids polyamic acid solution; the figure for the batch supplied is stated on the Certificate of Analysis | ISO 3251 |
| Thermal class and temperature index | Class 240, carried as a class number without a letter in the winding wire standards; temperature index matched to class 240 at the 20 000 h reference, stated for the wire construction supplied | IEC 60172 for the temperature index; thermal endurance to IEC 60216-1 |
| Film build, increase in conductor diameter | Grade 1 typically 0.015 to 0.060 mm and grade 2 typically 0.025 to 0.090 mm increase in diameter, on round copper conductor of 0.20 to 1.60 mm | Limits per IEC 60317-0-1; dimensions measured to IEC 60851-2 |
| Breakdown voltage, twisted pair at ambient temperature | 3.5 to 11 kV on grade 2 wire, rising with conductor diameter and build | IEC 60851-5 |
| Cut-through, softening under load | 350 °C to 390 °C, 110 K to 150 K above the rated thermal class | IEC 60851-6 |
| Heat shock | No cracking after 30 min at 260 °C (class temperature plus 20 K), wound on a mandrel of 1 to 5 times the conductor diameter | IEC 60851-6 |
| Resistance to solvents | No film softening, blistering or loss of adhesion after the specified solvent exposure; not resistant to strong alkali or prolonged hydrolysis | IEC 60851-4 |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Method | Wire enamelling line from polyamic acid solution, die or felt application |
| Conductor preparation | Bare round or rectangular copper, including silver and nickel plated copper for high temperature work, clean, dry and free of drawing lubricant and oxide |
| Passes and build | Ten to sixteen very thin passes to grade 1 or grade 2 build |
| Viscosity adjustment | Adjust only with the thinner specified for the grade, to suit die or felt application |
| Cure | Longer and hotter cure zone than the polyester chemistries require, with imidisation completed in the oven |
| Overcoat | Polyamide-imide topcoat where the slot is tight and abrasion during pull-in is the limiting factor |
| Terminations | Not solderable: terminations are stripped, welded or crimped |
Process. Applied on a wire enamelling line from polyamic acid solution in ten to sixteen very thin passes, with a longer and hotter cure zone than the polyester chemistries require and imidisation completed in the oven. Thermal class 240, which is designated as a bare class number in the winding wire standards and carries no letter.
6. Storage and handling
Store in the original closed containers in a cool, dry place at the temperature stated on the label, as polyamic acid solution is sensitive to moisture and heat, and let containers reach room temperature before opening. Shelf life is stated on the label and Certificate of Analysis. Handle and use the product in line with its Safety Data Sheet.
7. Safety and regulatory information
Read the Safety Data Sheet before use. Safety Data Sheets and regulatory declarations are issued by our technical centre against the product and batch supplied, so they are sent on request rather than published. Request a Safety Data Sheet or declaration.
This Technical Data Sheet is published for on-screen reference. The information is given in good faith from laboratory and application experience and describes typical values; it is not a specification and does not replace a trial on your own substrate and line. Arctic Materials may revise this sheet without notice. Issue 2026.09.
Technical Data Sheets on this site are for on-screen viewing. For a controlled copy, write to tech@arcticmaterials.com.
Other grades in this range
Need a Safety Data Sheet, a regulatory declaration or a grade specified to your line? Contact our technical centre.