Category Archive: Uncategorized

Flame Retardant Properties of Polypropylene (Formex, Nomex, Fishpaper)

Flame retardancy is important in electronic and electrical equipment materials to comply with fire safety standards. Polypropylene is a versatile material with a flame retardant capability, making it popular in various manufacturing applications.

This article will explore the flame retardant properties of polypropylene, specifically Formex, Nomex, and Fishpaper — the three types used by ESPE Manufacturing Co. We will delve into the features behind their flame retardancy and their applications.

What Is Flame Retardancy?

Flame retardant properties are the capacity of a material to hinder the progression of flames or delay the onset of a fire. They are particularly important in industries prioritizing fire safety, such as construction, transportation, and electronics and electrical equipment.

The function of flame-resistant compounds is to inhibit the chemical reactions that occur during combustion. This reduces the material’s combustibility and contribution to the spread of fire.

Numerous techniques exist for applying flame resistance to materials. These include using chemicals, coatings, and flame retardant fibers or fillers within the substance.

Polypropylene Materials

ESPE Manufacturing Co. works with various electrical insulating materials to meet the needs of various applications. Here are some of the materials we employ and provide:


Formex is a type of electrical insulation material made from flame retardant polypropylene. It prevents electrically charged components from arcing and protects the users, equipment, and maintenance personnel. Its properties also ensure that the material will not melt or combust up to 115 °C (239 °F).

This material has received a UL 94V-0 rating, indicating that it meets specific flame resistance criteria and has undergone Underwriters Laboratories (UL) testing. This proves that they do not propagate flames and extinguish them on their own within a few seconds.


Nomex is a meta-aramid material renowned for its ability to resist flames, which can be attributed to its distinctive chemical composition. The material consists of polyamide molecules with long chains, making them highly heat-resistant and difficult to ignite. When exposed to high temperatures, the polymer chains within Nomex link together. This forms a protective layer of char that insulates the material and slows down the combustion process.

This polypropylene type has a wide temperature range from -196 °C (-320 °F) to 250 °C (482 °F) without significant degradation in its mechanical properties. This makes it suitable for high-temperature environments, such as aerospace, marine, electrical, and automotive industries. Furthermore, it has been extensively tested and has received the UL 94V-0 rating.

Fishpaper and Vulcanized Fiber

Fishpaper is an electrical insulation material composed of thin layers of paper that have been treated with a thermosetting resin. The resin acts as a binding agent, holding the layers of paper together and providing the material with its flame retardant properties. Due to this composition, fishpaper has a high flame resistance and is not prone to igniting or supporting combustion.

This material has moderate heat resistance and can withstand up to 120 °C (248 °F). This temperature range is ideal for electrical insulation applications with a moderate heat exposure risk. However, specialized grades can withstand higher temperatures of up to 155 °C (311 °F) or even 180 °C (356 °F). It has also received the UL 94V-0 rating.

Partner With ESPE Manufacturing Co. for Premium Electrical Insulation Materials

ESPE Manufacturing has been a trusted provider of electrical insulators for more than 70 years! We serve a wide range of markets and have a deep understanding of our materials’ unique properties. We also have an expert team that can assist you in selecting the most suitable material for your specific needs.

Contact us today to discover more about our top-quality products and services! You can also request a quote, and we will gladly help you with your needs.

Material Spotlight: Fishpaper & Vulcanized Fibre

Click to ExpandMaterial-Spotlight-Fishpaper-Vulcanized-Fibre

Even though electricity is one of the breakthrough technologies that are most frequently utilized and relied upon, it is also one of the most hazardous when mishandled or when its uses are misunderstood. Therefore, electrical insulation has to play its role. Non-metallic materials — such as plastic, rubber, or PVC — are frequently used to create insulation. These materials are designed to limit the current flow between conductors.

Fishpaper and vulcanized fibre sheets are multi-functional engineering materials used in various mechanical and electrical applications, particularly electrical insulation. Although they may appear similar to one another, they have characteristic differences. Mechanically, these materials do not share the same tensile strength and tensile modulus, and their electrical properties — such as dielectric strength and arc resistance — also differ.

Let’s define what these two materials are.

Fishpaper and Vulcanized Fibre

The term “fishpaper” refers to electrical-grade vulcanized fibre sheets in general. It is a vulcanized cotton electrical insulation board or paper easily cut and shaped to insulate electric motors, generators, and transformers. This material is also a good choice for oil-filled transformers.

On the other hand, a vulcanized fibre is a chemically natural cellulose material that is free of adhesives and resins, making it environmentally friendly. It is a low-pressure laminate created by the reaction of cotton or natural wood with various chemicals such as acids, bases, and zinc chloride. Aside from that, vulcanized fibre sheets can be formed, slit, molded, or wound into tubes for use in various applications.

Vulcanized fibre can also be used for including washers, insulating plates, switch and appliance insulation, electric motor insulation, gaskets, automobile parts, luggage, patterns, and more.

Advantages of Fishpaper and Vulcanized Fibre

The following are the advantages of using fishpaper and vulcanized fibre:

  • Fishpaper and vulcanized fibre have excellent dielectric properties and are suitable for oil-filled inductors.
  • Mechanical strength. Because it is fibrous, fishpaper electrical insulation has high mechanical strength.
  • Heat resistance. Cellulosic paper is more heat-resistant than many plastic materials because it is hard and wear-resistant.
  • At low temperatures, fishpaper and vulcanized fibre retain more flexibility than plastic materials.
  • Cost-effective. Fishpaper and vulcanized fibre are suitable for diverse general-purpose applications due to their size, versatility, and resistance to heat, chemicals, and tear,

Fishpaper and Vulcanized Fibre As Insulators

Fishpaper and vulcanized fibre sheets are effective electrical insulators for various reasons. One of those is that they are durable and flexible, with unique combinations of strength and formability. Fishpaper is also insoluble in common solvents like benzene, petroleum, alcohol, ammonia, turpentine, naphtha, and ether.

Furthermore, fishpaper has a very light property, weighing roughly half the weight of aluminum. As a result, it’s an excellent insulator for applications where weight reduction is essential for maintaining maximum product performance and optimizing fuel efficiency. Some types of fishpaper insulation and vulcanized fibre — such as those that comply with UL-94 and ASTM D-365 standards — are also used in components such as wear plates, arc chutes, and circuit breaker baffles.

In addition to being used as electrical insulators, here are some of the other applications of electrical-grade fishpaper insulation in the mechanical and electrical industries:

  • Electronic devices
  • Automotive parts and components
  • Circuit breakers
  • Electrical instruments
  • Gaskets
  • Fuse tubes
  • Railroad track installation

On the other hand, the following are the common applications of vulcanized fibre:

  • Washers
  • Insulating plates
  • Switch and appliance insulation
  • Electric motor
  • Automobile parts
  • Luggage
  • Gaskets

ESPE Manufacturing Co., Inc. Services

Using quality components for insulation ensures electrical safety and helps retain the integrity of various equipment and devices. Not only is insulation crucial in avoiding accidents and property destruction, but it also protects the value of your products by preventing electrical damage and prolonging the lifespan of various industrial and commercial goods and equipment.

ESPE Manufacturing Co., Inc. manufactures a diverse range of vulcanized fibre and fishpaper products to meet the specific needs of our customers. Our employees are trained for the job, whether prototyping an intricate part on our laser or running production quantities on our mechanical and hydraulic cutting presses. So if you need vulcanized fibre sheets and fishpaper insulation products, ESPE has one of the Midwest’s most extensive inventories!

To find a specific insulation product that works for you, you can view our catalog or contact us if you have any questions or inquiries.

Guide: What Is Stamping?

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As the global markets continuously evolve, the demand to quickly produce large quantities of high-quality complex parts rises simultaneously. Because of this, stamping, a popular manufacturing process, has been sought-after by many manufacturers as a cost-effective and efficient solution to large-quantity manufacturing needs in various industries.

One of the popular processes in the manufacturing industry is metal stamping. However, non-metal stamping, especially stamped parts made from electrical insulation and barrier materials, is also gaining popularity among many manufacturers in fabricating different components for various purposes.

As a leading supplier of a large inventory of stamped products, ESPE Manufacturing Co. specializes in stamping electrical insulation, barrier materials, and other non-metallic materials such as plastic, rubber, paper, and more! This article will walk you through what stamping is in the manufacturing industry, its benefits, and its applications.

Stamping In Manufacturing

Also referred to as pressing, stamping is a manufacturing process of converting or altering flat sheets into different shapes to produce a valuable component or part. The process is usually carried out on sheet metal. But it can also be used on other non-metal materials, including a broad range of specialty polymers, aramid papers, neoprene, acrylic, and more.

The stamping process involves placing your material of choice in a stamping press where a tool and die surface form the workpiece into a final shape. Parts or components produced from stamping are used in automotive, electronics, medical, defense, aerospace, and many other sectors.

Non-Metal Stamping Operation

ESPE’s stamping operations involve slitting material and feeding it into the presses, where stamping takes place at 50-200 strokes per minute.

When selecting a non-metal material for a stamping operation, it is essential to consider a few factors to achieve optimal production and performance, including the material’s properties and characteristics.

Manufacturers should look at the material’s mechanical, electrical, magnetic, and thermal properties, as well as its durability and performance under normal and high-stress operating conditions. Moreover, the design for stamping should also meet the application’s absorption, compression, and alignment requirements.

Benefits Of Stamping

Manufacturers utilize the stamping technique because it is time- and cost-efficient. Specifically, stamping provides the following advantages:


Stamping reaches a micron-level accuracy on the cuts applied to the sheet material. Hence, this process’s sophistication and intricate nature allow manufacturers to shape and sell parts in the most complex forms at the highest quality.

Cost Efficiency

Stamping enables manufacturers to mass produce parts with lower labor costs, which helps to achieve lesser expenditures and higher profit.


Detailed part specifications are easily achieved through stamping, as it allows for alteration of the shape and design of material into any desired form, even the more complex ones.

Advantages of Non-Metallic Stamping

In addition to the general benefits of stamping, there are a couple of advantages in stamping non-metallic parts and products, like electrical barriers and insulators, including:

Mass Production

The tools that shape and cut sheet materials are called stamping dies. These dies can be used for multiple production runs or swapped out quickly for different parts, making the stamping process fast and efficient.

Higher Accuracy

With durable dies set up, the stamping process can produce high volumes of identical parts with strict tolerances.


The common industries that utilize stamped electrical barriers and insulators, and other non-metallic parts and components include:

  • Aerospace
  • Agriculture
  • Architecture
  • Automotive
  • Dental
  • Electronics
  • Food and Beverage
  • Machine tools
  • Marine
  • Medical
  • Oil and gas
  • Packaging
  • Renewable energy
  • And more

Top-Quality Stamping Services At ESPE Manufacturing Co.

ESPE Manufacturing Co. understands the fundamental role of stamping in responding to the manufacturing industry’s growing demands for different components or custom parts supply. We live up to our reputation as the technical authority in producing the best quality stamped parts.

Our stamping outputs are made from electrical insulation and barrier materials, such as ITW Formex®, ITW Statex®, and Nomex®, as well as vulcanized fiber and fishpaper. We also offer non-metal materials like polymers, vinyl, acrylic, nylon, and aramid papers. We manufacture thousands of products from stamping, such as washers, arc chutes, and other insulators — from prototype to production quantities.

ESPE Manufacturing Co. is your partner for proficient and top-quality stamping operations that involve compound die, progressive die, and punch press, which allow us to sustain and meet any geometric complexities, designs, and specifications!

Contact us directly to learn more about our stamping capabilities or request a quote today, and our friendly experts will be happy to assist you.