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Frequently Asked Questions

Below is a sampling of some of the most frequently asked questions about applications related to Nomex® brand insulation. If you have any additional questions you would like addressed, contact us.

What effect does moisture have on Nomex® insulation? 

Nomex® paper is hygroscopic, and will reach equilibrium at room temperature at a moisture content equivalent to approximately 10% of the surrounding relative humidity (i.e., 5% moisture content at 50% RH). With increased moisture content, some mechanical properties (such as elongation) actually increase, and most stay within 20% of the dry value under conditions up to 95% RH. Dimensional change occurs with moisture content, with the largest effect being in the Z (or thickness) direction. Electrical properties change very little, even in an environment at 95% RH. When used properly, there is not a concern, as long as the paper is allowed to breathe freely. If used in a sealed system, however, Nomex® paper should be dried prior to further processing.

The DuPont brochure, titled "Moisture Effects and Processing Information for Nomex®” paper, provides more detail on this subject. Click here to obtain a copy.

I need help identifying a new UL system to produce my electrical equipment. What does DuPont have to offer? 

The DuPont brochure titled “UL-Recognized 600 Volt Class Electrical Insulation Systems Based on Nomex®” provides detailed information on insulation systems. In addition, these insulation systems are listed in the literature page of this web site. Many new systems based on Nomex® brand papers and pressboards are under development, as part of our ongoing research and product innovation.

Contact us to get information on some of our most recent innovations. DuPont Engineering Polymers has many additional UL systems for their RYNITE® and ZYTEL® resins, many of which contain Nomex® insulation materials as major insulation. Their systems are published in a brochure titled, “Thermoplastics for UL/IEC Electrical Insulation Systems: Transformers, Motors, Coils, Relays, and Encapsulated Components.” You can obtain this information by contacting the Engineering Polymer group at their web site,

I have an application for a Nomex® material which is thicker than 30 mil (0.76 mm) Type 410. What would you recommend?

DuPont offers three types of Nomex® pressboard, ranging in thickness from 40 mils (1.0 mm) to 380 mils (9.6 mm). These products range in density from 0.5 g/cc (Type 992) to 1.15 g/cc (Type 994). Depending on the application, one of these types of pressboard may likely satisfy your requirement. Click here to get more information on our Type 992, 993 and 994 pressboards.

Where can I purchase Nomex®  products?

Click here.