At Mitsubishi Chemical Group (MCG), we know electrical questions often land on your desk. Let us help by digging into the three terms that matter: dielectric strength, dielectric constant, and dissipation factor.

Dielectric Strength

As we know, plastics are insulators, meaning they prevent electrons from passing through them to protect us or other devices from electrical shocks or conductivity. Each material has a specific insulative capacity that can range from hundreds of volts per mil (0.001*) to more than 1000 volts per mil. Dielectric strength measures volts a material will insulate per mil.

Example calculation:

A block of Duratron™ PEI at half-inch thickness with a dielectric strength of 830 volts/mil can insulate 415,000 volts.
So even a thin plastic can block very high voltages!

Dielectric Constant (DC) and Dissipation Factor (DF)

Two terms you will almost always see used together are:

Dielectric constant (DC)—How much electrical energy a material stores in an electric field. Lower DC means the material stores less charge—often desirable for insulative applications.

Dissipation factor (DF)—The energy lost as heat compared to stored energy. Lower DF means less heat build-up within strong electrical fields.

The best dielectric materials hold DC and DF steady across temperature and frequency ranges. The chart below shows how Duratron™ PEI keeps its dielectric behavior stable in high temperatures and gigahertz (GHz) frequency ranges.

 

Duratron™ PEI

Sultron™ PPSU

Duratron™ PAI

Duratron™ PI
Dielectric strength (volts/mil) 830 360 580 700
Dielectric constant at 1 megahertz (MHz)

3.15

 3.4 4.2 3.41
Dissipation factor at 1 MHz 0.0013 0.0017 0.026 0.0038

Quick Checklist for Customer Calls

When a customer asks about materials for electrical performance, walk through these questions to guide them to the right choice:

Insulation or ESD?

  • Do they need an insulating material or a statically dissipative (ESD) material?

Voltage and Thickness

  • For insulation: What voltage must the material withstand?
  • What is the minimum plastic thickness required?

Static Dissipation Needs

  • For ESD: Which conductivity/resistivity range and heat deflection temperature (HDT) fit the application?
  • Refer to MCG’s ESD product line for options.

Frequency Range

  • Is the application above 60 Hz (typical for motors/appliances)?
  • If so, what frequency in MHz or GHz?

Environmental Factors

  • Will the part face high temperatures, chemicals, hot water, or steam?
  

 

MCG has your back

Our technical team helps match materials to electrical specs. Questions? Contact us.

Learn more

Simplify Your Workflow with MCAM Connect

Easily manage orders, access critical data, and get tailored support — all from one powerful platform.