YT56 Semi-Calendered Aramid Paper
YT56 Semi-Calendered Aramid Paper
Semi-calendered aramid paper offering a balance of flexibility, varnish absorption, and mechanical stiffness. Perfect for electrical barrier shielding and phase insulation.
Priced per requirement — tell us grade, width, thickness and quantity and we quote against it.
Technical specifications
| Composition | 100% meta-aramid fibre |
|---|---|
| Thermal class | Class H (180 °C) / Class R (220 °C) |
| Thickness range | 0.05–0.76 mm (2–30 mil), typical |
| Width range | Slit 10–1,000 mm |
| Density | 0.7–1.1 g/cm³ calendered, 0.3–0.6 g/cm³ uncalendered |
| Dielectric strength | 10–35 kV/mm, varies with thickness and grade |
| Limiting oxygen index | ≥ 28% — does not melt or support combustion |
| Form | Reels, slit to width; sheets to size on request |
| Compliance | UL, CE, RoHS, REACH |
Typical values for this material class, given as a guide. The datasheet carries the property table, test methods and tolerances for the grade and is the governing document.
Overview
YT56 is meta-aramid paper calendered part-way — denser and smoother than an uncalendered sheet, more open and more formable than a fully calendered one. It exists because a good many applications need both properties and cannot have either in full measure.
The result is a paper that still absorbs varnish usefully, but has enough body and surface finish to be handled, folded and inserted cleanly. Where a fully calendered sheet would resist impregnation and an uncalendered one would lack stiffness, YT56 sits between them.
The middle grade
Across the three finishes of the same fibre:
- YT510 (calendered) — maximum density, dielectric strength and machine handling
- YT56 (semi-calendered) — a working balance of stiffness, formability and varnish uptake
- YT511 (uncalendered) — maximum porosity and resin absorption
YT56 is usually the answer when a winding is partially impregnated, or when the insulation has to be folded or formed and then varnished.
Key properties
- Balanced density — useful varnish absorption with real mechanical stiffness
- Folds and forms without cracking at the crease
- Continuous service at 180 °C (Class H), used to 220 °C
- Good tear and puncture resistance for handling and insertion
- Inherently flame resistant
- Dimensionally stable through thermal cycling
Applications
Phase insulation
Phase-to-phase separators in motors and generators, where the part is formed to shape before insertion.
Electrical barriers
Barrier and shielding layers that must be cut, folded and located precisely.
Slot liners
Slot insulation in machines that are varnished after winding rather than fully impregnated.
Coil wrapping
Wrapping where the material must conform without splitting at the fold.
Standards and compliance
- UL recognised component — certification held by the manufacturer
- CE marked
- RoHS compliant
- REACH compliant
- Manufactured under ISO 9001:2015
Certificates of conformity and mill test certificates are supplied with each shipment. Third-party testing can be arranged on request where a specification demands independent verification.
Sizes, packing and supply
- Thickness: 0.05–0.76 mm, typical range
- Width: slit 10–1,000 mm
- Form: reels; sheets, folded parts and die-cut parts to drawing
Quality and inspection
Every consignment is inspected before shipment and supplied with its mill certificate. For repeat programmes we hold the approved specification on file so a reorder repeats a known outcome rather than reopening the conversation.
Frequently asked questions
When should I use YT56 instead of YT510?
When the part has to be folded or formed, or when the winding is varnished rather than fully impregnated. A fully calendered sheet is stiffer and can crack at a tight fold; YT56 takes the crease.
Does semi-calendering reduce dielectric strength?
It sits between the calendered and uncalendered grades, as you would expect from the density. The datasheet gives the values.
Can it be die-cut?
Yes, and it holds a clean edge. Send the drawing and we will quote tooling and parts separately.
Is it suitable for automated slot insertion?
Usually, though a fully calendered sheet feeds more predictably at speed. If the line runs fast, tell us and we will suggest which to trial.
What thickness should I specify?
That follows from the voltage stress and the mechanical duty. Describe the application and we will recommend against it.
Related products
Next step
Tell us the size and quantity
Send the thickness, slit width and annual volume for https://aramidpapers.com/wp-content/themes/aramidpapers and we come back with a costed offer, a firm lead time and the mill certificate you will receive with it.