What are the different types of electrical insulation?

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Because they prevent the passage of electrical current between two conductors, electrical insulators are used in many applications. Below are the different electrical insulation solutions offered by ADDEV Materials.

Technical insulating films

These thin (<0.5mm) insulating polymer films, available in rolls, formats or cut peices, have a variable composition and applications

Examples:

Polyester films Mylar®, Lumirror®: PET, marketed in several thicknesses, compatible with custom cutting. It is a very good dielectric, ideal for a very wide range of applications (-70°C to +150°C).
Polyester films Kapton® polyimide films: PI, this high performance material is intended for high temperature dielectric use (up to 400°C in short term thermal peak)

Flexible electrical insulating papers

These insulating papers are less than 1mm thick; single-film or polymers, or made of fibres, compressed, or in non-woven form, or evan an assembly of these two designs.

Examples:

Nomex® papers and boards: based on aromatic polyamide for excellent thermal stability, good dielectric rigidity and high mechanical strength Typical use: transformers, generators, hybrid vehicles
Nokamex® laminates: assembly of a Kapton® polyimide film and Nomex® aramid paper

Adhesive insulators

Adhesive electrical insulators are flexible materials, in the form of rolls, with support; papers; films; glass fabrics or foams and coated with an adhesive mass.

There are mainly 5 types of insulating supports intended to receive one of the 3 types of adhesive mass, on 1 or 2 faces.

3 types of adhesive masses:

Rubber adhesive mass insulators: the most adhesive at low temperatures
Insulators with acrylic adhesive mass: the most versatile
Silicone adhesive mass insulators: for high temperatures

Important to note: Silicone adhesives have a particularly excellent resistance to extreme temperatures. Logically, silicone adhesives are therefore reserved for high-temperature insulating materials such as Kapton® or Teflon®.

Strengths

Weaknesses

Application Examples

Rubber

High Tack
Versatility
Low Cost

Low resistance to high and low temperatures and chemical aggression

Small transformers, mechanical process maintenance...

Acrylic

Increasing adhesive strength over time
High final adhesion
Mechanical resistance
Resistance to UV, cold, humidity, solvents...

Intermediate initial adhesion

Transformers, motors, mechanical maintenance under 150°C

Silicone

Resistance to extreme temperatures
Excellent adhesion on siliconized materials

Low initial adhesion
Low resistance to hydrocarbons and plasticizers

Extreme temperature applications

5 types of insulating materials

PET polyester films
Glass fabrics
Nomex® papers
Kapton® polyimide films
Teflon® fluorinated films

In addition to being known for their non-stick properties, fluoropolymers (PTFE, FEP, PFA, etc...) have much better dielectric properties than other materials.

Example:

Among the different types of fluoropolymer films, single-sided PTFE Teflon® tapes coated with a silicone adhesive mass, have high dielectric strength, high chemical resistance and excellent temperature resistance.

2 types of adhesives: single or double sided

An adhesive tape can be covered with an adhesive mass on one or both sides, depending on its use.

Double sided: assembly function (in addition to the electrical insulation provided by the backing)
Single-sided: protection, sliding... (in addition to the electrical insulating side provided by the support)

Example:

Kapton® type double sided tapes are composed of a polyimide film covered on both sides with a high temperature silicone adhesive mass. This product is ideal for electronic and electrical applications.

Rigid laminated insulation

This range consists of rigid materials, in the form of tubes or boards (thickness 0.1mm to several centimeters), designed by an assembly of several layers:

Insulating resin: phenolic, polyester, epoxy, or silicone
Added reinforcements: papers, glass mat or polyester, glass cloth, mica...

This method combines the properties of different electrical insulators to design thick and machinable materials.

Liquid insulators

It is also possible to ensure the electrical insulation of hollow or difficult to access areas by using materials in liquid form, such as varnishes, mastics, and impregnation resigns

Single or two-component epoxy, to combine mechanical performance and dielectric character
Silicone, for electrical insulation, high temperature resistance, and protection against vibrations