Category Archive: Products

Formex for Insulation of Batteries & Printed Circuit Boards (PCBs)

Electrical insulation involves non-electrically conductive material used to control the flow of electricity and protect sensitive components. Various materials can be used, such as rubber, plastic or material like Formex for insulation. These materials work by blocking the passage of electrons more effectively than semiconducting and conducting materials. This means that they can be used as a protective barrier around the conductor, ensuring energy stays on a specific path and doesn’t interact with other components, causing short-circuiting.

Importance of PCB & Battery Insulation

In applications involving PCBs, insulation acts as the dielectric material used to separate conducting elements and layers. Most PCBs used today are multilayered, which means multiple adhesion points are present. This increased board height requires more soldering and makes proper insulation vital to the board’s effectiveness. In PCB applications, having a thorough understanding of your PCB’s construction is the best way to ensure it’s insulated adequately and can operate at its highest potential.

Another key application for electrical insulation is in batteries. Electrical vehicle batteries, for example, require insulation between each component to ensure no electrical arc can arise between battery components. This is a necessary precaution to prevent fires, shocks, high temperatures, short circuits, and more.

When choosing a material to insulate PCBs and batteries, there are several factors that should be considered. One of the primary concerns is the material’s thickness in relation to its efficiency. Insulating material needs to be highly effective, but thickness also needs to be taken into account. Certain insulation applications feature highly compact components that are not suited to a particularly thick material.

It’s also important to consider what type of processing your insulator should undergo. Certain insulation materials are significantly easier to process than others and, depending on your application, this may be a significant concern. However, an easy-to-process material might not perform according to your required standards. Insulation weight and cost-to-function ratio should also be factored into decision-making. For PCB and battery insulation applications, a particularly high-performing material is ITW Formex. This material is uniquely suited to PCB and battery applications, meeting all of the typical demands.

Why Formex?

ITW Formex is ideal for protecting delicate components and is widely used throughout many applications. It offers excellent dielectric strength and provides reliable mechanical protection. Formex can be formed into even the most complex three-dimensional shapes by die-cutting, scoring, and bending. In PCB insulation applications, Formex is used for barriers between PC boards as well as between PC boards and housings.

Formex electrical insulation is made from polypropylene, which is lightweight and inexpensive, while meeting rigorous electrical barrier and insulation requirements. With a flame class rating of UL 94V-0, Formex has excellent flame-retardant properties and will not combust or melt at temperatures up to 239° F.

Additionally, ITW Formex features several key characteristics that allow it to outperform other insulation materials, such as preventing electrically charged components from arcing. Formex is ideal for many types of EV battery applications as it protects from contact corrosion, provides EMI shielding capabilities, and more. For electric vehicle battery applications, Formex stands up to chemical, mechanical, and environmental demands.

ESPE Manufacturing: Your Source for Reliable Insulation

PCBs and batteries are used throughout nearly every industry and require high performing, reliable insulation. Formex contains many beneficial characteristics that make it ideally suited to these applications. In addition to being uniquely easy to shape, it also features notable strength and valuable fire-retardant properties, all while being cost-effective.

ESPE Manufacturing Co., Inc., has been providing high-quality electrical insulation solutions since 1948 and features one of the largest inventories in the Midwest. We offer ITW Formex rolls and sheets and carry several varieties suitable for a wide selection of applications. Our experts can help you select the best type for your project. Browse our catalog or contact us to get started. To partner with us and take advantage of Formex insulation for your application, request a quote today.


Material Spotlight: Teflon® for Electrical Insulation 

ESPE Manufacturing works with a number of electrical insulation materials and with a variety of fabrication methods. Even the most complex specifications are manufactured accurately using techniques such as laser cutting, die cutting, digital plastic cutting, and more. We provide prototyping services and can fabricate custom parts in both high and low production volumes. Our products are available in many suitable materials, including PTFE or Teflon® for electrical insulation purposes.

This blog post will discuss what Teflon® is as well as the many advantages of using Teflon® for electrical insulation products.

What is Teflon®?

Teflon® is the widely recognized brand name for polytetrafluoroethylene (PTFE). PTFE is a type of plastic that is used to coat various products and equipment, creating a non-stick, waterproof, non-reactive, and corrosion-resistant protective barrier. Teflon® is extensively used throughout various industries, including automotive, construction, aerospace, and more, for applications such as pipes, gears, wires, and cables.

Why is Teflon® Good for Electrical Insulation?

Teflon® is impervious to nearly all solvents and chemicals, including those frequently used in electronics manufacturing. It is a very resilient, non-reactive material that can withstand temperatures ranging from -454° F to 600° F (-234° C to 315° C), making it an excellent insulator for electrical applications exposed to extreme heat or cold.

Teflon® is composed of carbon-fluorine bonds that are very flexible, even after significant bending and stressing. Teflon® insulated wires cannot be cross-linked and have a long, reliable flex life. The extreme durability of Teflon® ensures long-lasting protection of electrical components.

Teflon® also displays excellent dielectric strength, making it an excellent electrical insulator. Teflon® coated components are very low friction, meaning components will experience minimal resistance. At ESPE Manufacturing, we can produce a variety of Teflon® electrical insulation products, including:

  • Bearings
  • Bushings
  • Gears
  • Slide plates
  • Piston rings
  • Seals
  • O-rings
  • Spacers
  • And more

Advantages and Benefits of Teflon® Parts

There are many benefits of Teflon® parts, including:

  • Versatility. One of the primary benefits of Teflon® parts is their versatility, meaning it is suitable for an extensive range of applications and industries.
  • Corrosion resistance. Another key advantage of Teflon® parts is their corrosion resistance, which makes them especially useful for electrical insulation.
  • Water and oil resistance. Teflon® parts repel water and oil, which increases the lifetime of the part itself as well as the application it’s used in.
  • Non-stick. Teflon® is non-stick, meaning Teflon® parts are easy to clean, typically only requiring a wipe down.
  • Low friction. Teflon® parts exhibit low friction properties, which offer reduced wear and longer-lasting components. This makes Teflon® parts an excellent option for industrial applications involving parts or gears that slide against each other.
  • Dielectric properties and high melting point. The non-conductive properties and high melting point of Teflon® parts make them a popular choice for electrical wiring and insulation for a variety of industries.

Teflon® Electrical Insulation from ESPE Manufacturing

The significant advantages of Teflon® make it a natural choice for electrical insulation projects. Teflon® parts work longer and more effectively than alternatives and can easily be incorporated into a wide array of applications. ESPE Manufacturing offers a wide range of Teflon® fabrication services that can be customized to meet your application’s exact needs. We have a long history of delivering effective non-metallic solutions, and we possess one of the largest electrical insulation inventories in the Midwest. To learn more, view our catalog or contact us today.

Material Spotlight: Mylar®

Electrical insulation is crucial in various applications to prevent the free flow of electricity. Mylar helps channel electricity where it needs to go while preventing short circuits and eliminating electrocution dangers. ESPE Manufacturing Co., Inc. has an enormous selection of materials to fabricate components and parts that can be used as electrical insulation, including Mylar.

What is Mylar?

In the 1950s, a trio of chemical companies, Hoechst, DuPont, and Imperial Chemical, developed Mylar–a stretched polyester film that is commonly used for solar filters, protective plastic coatings, insulators, space blankets, and shiny helium balloons. The technical composition of the groundbreaking material is biaxially oriented polyethylene terephthalate, or BoPET. NASA was one of the first to use and experience the benefits in its 1964 Echo II balloon.

To create Mylar, molten PET is extruded as a thin film over a chilled roller or other surface. Special machinery draws the film in biaxial directions using heated rollers. The final step involves setting the film by holding it under pressure at a high temperature. The result is an extremely smooth and pure film that adheres to itself. To prevent this, inorganic particles or metals can be embedded in the surface.

The properties of Mylar make it an excellent component for food packaging applications such as yogurt lids, roasting bags, and various foil packages. Because of its electrical insulating properties, it is often used in manufacturing, automotive, electronics, and space travel applications.


The properties listed below allow for an ideal choice in a wide variety of applications:

  • Dielectric strength. Mylar is an excellent electrical insulator with a typical DC dielectric strength of 11.0 kV/mil and a typical AC dielectric strength of 7.0 kV/mil.
  • Corona threshold voltage. Mylar has one of the highest corona resistance levels of any plastic film, which makes it able to endure short surges of overvoltages easily.
  • Dielectric constant. The typical dielectric constant ranges from 2.8 to 3.7, depending on the temperature of the film.
  • Dissipation factor. The typical dissipation factor of Mylar ranges from 0.0002 to 0.016, depending on the temperature of the film.
  • Insulation Resistance. Mylar film has exceptional insulation resistance over a broad range of temperatures.
  • Volume Resistivity. The volume resistivity of the material decreases as temperature increases, with Mylar Type C having about one order of magnitude higher volume resistivity than Type EL film at 257° F.
  • Tracking Resistance. When dry, the material doesn’t track, but moisture can lead to tracking erosion.
  • Arc Resistance. Mylar possesses an arc resistance time of 73 to 94 seconds. This shows that the material has an advantage over materials that track.

The Advantages of Mylar for Electrical Insulation

The benefits of Mylar film come from its excellent electrical insulation properties under a wide variety of conditions. In addition to those listed above, it also includes the following advantages for electrical insulation:

Tensile strength and toughness

Mylar is tough and has a higher tensile strength than most insulating materials. It has a tensile strength of 25,000 psi and elongation at 170% without breaking.


Creep measurements indicate how a material deforms under a wide range of mechanical stressors. Under various conditions, the material resists creep very well.

Thermal aging

UL thermal aging standards show that Mylar has a temperature index of 302° F. This means that it will not degrade at service temperatures below 302° F, providing a long service life for various electrical insulator applications.

Mylar Available from ESPE Manufacturing

Mylar is one of many electrical insulation materials, and it provides a particularly wide range of benefits for industries such as automotive, electrical, lighting, wind energy, and many others. At ESPE, we offer a wide range of electrical insulation materials to fit the specifications of your project. For more information about this material, or to get started on your electrical insulation solution, contact us or request a quote today.

Mylar benefits


What to Know About Electrical Insulating Materials


At ESPE Manufacturing, we specialize in the manufacture of high-quality custom plastic parts and products, including electrical insulating materials. We maintain an extensive inventory of non-metallic materials for use in our manufacturing operations and distribution to our customers. One of our core material offerings is electrical insulation. Below, we provide an overview of this material, including what it is, why it is needed, how it is used, typical applications, and types available.

The 5 Basic Aspects of Electrical Insulation

1. What Is Electrical Insulation?

Electrical insulation refers to materials that do not allow electricity to flow through them freely (e.g., rubber or plastic). In contrast, conductors and semiconductors do allow electricity to flow through them freely (e.g., copper). This difference in performance stems from the difference in their resistivity. Electrical insulating materials have higher resistivity than semiconducting and conducting materials, which means electrons do not pass as easily through the former as they do through the latter.

electrical insulating vs conducting materials

2. Why Is It Needed?

Electrical insulators help control the flow of electricity. They ensure energy reaches the desired destination within the system by acting as a barrier around the conductor, preventing the energy from straying from the preferred path. In doing so, they also prevent electricity from flowing to other components, which can cause short-circuiting or electrocution depending on the configuration of the system.

3. A Glimpse at the Process

The following illustration points out the process of electrical insulation:

electrical insulation

4. Applications That Use Electrical Insulation

Some of the primary applications that require electrical insulation include:

  • Automotive components
  • Computers and computer peripherals
  • Consumer products
  • Conventional and uninterruptible power supplies
  • Electrical and power distribution systems
  • Lighting
  • Medical equipment
  • Telecommunications equipment

5. Commonly Used Electrical Insulation Materials

There are many types of electrical insulation materials available. Some of the most commonly used include:

  • Cardboard/Paper: These materials are a cost-effective option for insulation applications involving low heat and voltages.
  • Clay (ceramic or porcelain): This material is the standard for high-voltage and radio-frequency (RF) insulators.
  • Glass (limestone, silica, and soda ash): This material is used occasionally in low-voltage applications.
  • Mica: This material offers good electrical insulation and thermal conduction properties.
  • Perfluoroalkoxy (PFA): This material is flexible, transparent, and chemical resistant. It is commonly used in near-ocean applications due to its salt spray resistance.
  • Rubber: This material was used as an insulation in natural and synthetic variations up until the 1950s. However, it has since been largely replaced with plastics.

The experts at ESPE Manufacturing fabricate a variety of custom parts and products from electrical insulation material. Check out the list below to see the material options available.

Custom Manufactured Electrical Insulating Materials

Electrical Insulation Material Offerings and Options at ESPE

At ESPE, we utilize a wide range of electrical insulating materials in our custom manufacturing operations. The primary materials we work with are:

  • Formex: Formex is a brand of electrical insulation materials, all of which are made from flame-retardant polypropylene. They are a versatile and cost-effective solution for a variety of applications, ranging from consumer appliances and electronics to commercial data centers to industrial-scale systems.
  • Nomex: Nomex is a line of paper and pressboard insulation products. These meta-aramid polymer materials offer chemical, thermal, and radiation resistance in addition to their electrical insulation properties. They are commonly used in the aerospace, automotive, power generation, and marine industries.
  • Fishpaper/Vulcanized Fibre: Fishpaper is the generic term for electrical grade vulcanized fibre. It is lightweight, easy to work, and resistant to hot and cold conditions. It is often used in the production of components such as bushings, washers, gaskets, and more. Fibre is the generic term for commercial grade vulcanized fibre. It is hard, durable, and chemically pure and offers excellent strength, flexibility, and workability. It is often used in the manufacture of components such as gaskets, insulating plates, and washers.

We also offer a variety of other types and grades of electrical insulating plastics and papers.

ESPE Manufacturing: Your Expert and Partner for Electrical Insulation

Electrical insulation is essential to ensuring electrical and electronic devices, equipment, and systems are safe. However, the type employed depends on the application, with different applications requiring different electrical resistivity and other physical, mechanical, chemical, and thermal properties. While determining which electrical insulating materials are right for your application can be difficult, the experts at ESPE Manufacturing are here to help.

Whether you’re looking for an electrical insulation material supplier or a manufacturer of electrical insulating parts and products, we can meet your needs. To learn more about our material offerings and options, check out our material catalog. To discuss your material or manufacturing needs with one of our experts, contact us or request a quote today.