High Temp, Fireproof, Flexible Material: Rishon® vs. Rubber

Rubber is an essential material used in several industries. Rubber has played an important role throughout the development of human civilization and continues to be of great importance today.  The use of rubber is so significant that the global market size of rubber stood at USD 40.77 Billion in 2019 and is projected to reach USD 51.21 Billion by 2027.  Rishon components have replaced rubber components in the aerospace industry (as well as others), in a variety of applications and for several important reasons.


What is Rishon?

Rishon is a material which was created by RCF Technologies in 1975. It is a combination of a proprietary silicone and fiberglass (in most cases) although other substrates can be used. The elastomer is coated onto the fabric and forced through the weave of the fabric under heat and pressure forming a homogeneous material.

Rishon material can be:
  • Flexible or rigid
  • Has an operating temperature range of -170°F to +850°F
  • Is fireproof (Rishon is an FAA approved Fire Barrier in thicknesses as low as .037”)
  • Is chemically compatible with most fluids (including Skydrol)
  • Is an excellent vulcanizing material
  • Absorbs sound and vibration
  • Insulates against heat and flame
  • Is electrically nonconductive, but can be made electrically conductive with almost no added weight


Rishon is used primarily in the aerospace industry, though has also been used in the automotive, Industrial, Marine and Medical sectors as well. Rishon material is used by RCF Technologies to design and manufacture components such as:

These products are principally used for applications requiring high temperatures or fireproofing and offer longer life and lighter weight than most components made utilizing other materials.


Rubber Temperature Table

Low F
High F
Rishon® -170° 850°
Natural Rubber  -67° 180°
Neoprene -50° 275°
Silicone -70° 570°
Nitrile -30° 250°
EPDM -60° 300°
SBR -50° 225°
Butyl -75° 250°
Fluorosilicone -100° 350°

Natural Rubber

Rubber is a material that was originally made from natural sources such as the rubber tree and other plants (including dandelions which produce the latex that natural rubber is made from).

Natural rubber has:
  • Good durability
  • A temperature range of -67°F to +180°F
  • Is elastic
  • Is flexible
  • Is a good electrical insulator
  • Is resistant to many corrosive substances
  • Has resistance to degrading, abrasions, and surface friction

Natural rubber is used in many consumer and industrial items, including tires, gloves, some types of foam rubber, flooring and roofing, balls, and insulation.



Neoprene is a synthetic rubber made up of carbon, hydrogen, and chlorine polymers and was invented in 1930. It is used in applications that face harsh conditions and a lot of wear, such as automotive and industrial applications.

Neoprene has:
  • A temperature range of -50°F to +275°F
  • Is resistant to oil and solvents
  • Is chemically inert
  • Has high tensile strength
  • Is flexible
  • Is weather and flame resistant

Neoprene can however absorb water over time and does not work well as an electrical insulator.


Silicone Rubber

Silicone rubber is:
  • Generally stable
  • Non-reactive to most chemicals
  • Has a temperature range of -70°F to 570°F
  • Is resistant to ultraviolet rays, ozone, and fire.

Silicone rubber is manufactured in many different colors and is very malleable, available as both solid and liquid products.


Nitrile Rubber

Nitrile rubber has:
  • A temperature range of -30°F to +250°F
  • Is resistant to oil and water
  • Is quite durable


EPDM Rubber

EPDM rubber is a synthetic rubber compound and has:
  • A temperature range of -60°F to +300°F
  • Insulates
  • Reduces noise

EPDM rubber however, is not resistant against petroleum-based oils, mineral oils, and some other lubricants.


SBR Rubber

SBR rubber has:
  • A temperature range of -50°F to +225°F
  • Is hard and durable
  • Is resistant to some fluids


Butyl Rubber

Butyl rubber, also known as isobutylene isoprene, has:
  • A temperature range of -75°F to +250°F
  • Has low moisture and gas permeability
  • Has good shock absorption


Fluorosilicone Rubber

Fluorosilicone rubber, also known as FVMQ, has:
  • A temperature range of -100°F to +350°F
  • Is resistant to transmission fluids, engine oils, fire, synthetic lubricants, and ozone

Both natural and artificial rubbers are used in a variety of applications and across most industries. Each rubber varies regarding elasticity, electrical insulating properties, resistance to impact, water, cold, and abrasion, temperature range and more.

For more information about Rishon Material, and RCF Technologies products, please contact us today!

What Are Fireproof Gaskets?

Combustion requires three elements: heat, combustible material, and oxygen. Combined, they contribute to the sequence of reactions that cause incineration: 

  1. Pyrolysis. This process occurs when a combustible material like plastic begins to soften and decompose under temperatures that exceed its thermal resistance capabilities. The decomposition of the material produces flammable gases (chain fragments or hydrogen radicals).
  2. Ignition. As oxygen mixes with these gases, it creates a combustible mixture, which ignites as temperatures reach a certain level. 
  3. Renewal. The heat released during combustion continues to react with the melting material, releasing additional combustible gases that renew the combustion cycle.

Fireproof gaskets are gaskets designed to mitigate or eliminate the occurrence and spread of fire. They are made of materials that resist softening, igniting, and/or producing combustible gases under high-temperatures, ultimately reducing the risk of incineration.

When designing and manufacturing fireproof gaskets, one of the primary challenges is identifying and sourcing a material that demonstrates both the desired flame retardant properties and the mechanical and chemical properties required to achieve a proper seal. In addition to flame retardance and seal production, other key performance characteristics include: 

  • Ability to adhere to various substrates
  • Low water absorption
  • Resilience
  • Tear resistance
  • Temperature range

Types of Materials Used for Fireproof Gaskets

Industry professionals use a variety of high-temperature materials to manufacture fireproof gaskets. Some of the most commonly employed are: 

  • Rishon®
  • EPDM
  • Neoprene
  • Viton
  • Silicone

Applications of Fireproof Gaskets

Fireproof gaskets serve a critical role in a wide range of industrial applications, preventing or delaying the spread of fire that can lead to damage to sensitive equipment or injury to employees. Examples of common use cases for these components include:

  • Appliances, such as refrigerators, washers, dryers
  • Consumer electronic devices, such as computers and laptops
  • Engines
  • Industrial and commercial electronic equipment and systems
  • Lighting fixtures and systems

Fireproof Rishon Gaskets from RCF Technologies

RCF Technologies specializes in creating custom gaskets with our proprietary Rishon material. We have been creating seals, gaskets, and other industrial parts for over 40 years. Rishon material combines the best elements of fabrics and elastomers to create one homogenous, durable material. Rishon material and products made from Rishon are:

  • Chemically compatible 
  • Fireproof
  • Durable
  • Lightweight
  • Temperature resistant

Contact RCF Technologies today to learn more about our custom gaskets and other industrial parts.

Benefits of High-Temperature Materials in Aviation

High-temperature materials are critical to aviation applications. Aircraft engines can reach temperatures as high as 2100°C, and vehicles at high altitudes are subject to extreme temperature fluctuations. To ensure safe and reliable operation, aircraft equipment and components must be capable of withstanding these temperatures, as well as high pressure, corrosion, vibrations, and impact. Fortunately, with advances in materials technology, a variety of heat-resistant materials have become available for use in aviation.

High-Temperature Materials

Composite materials have become particularly popular in aviation since the 1980s and consist of two or more blended materials to produce a final product that exhibits characteristics different from those of the base materials. Composites used for aviation typically offer exceptional resistance to impacts, fatigue, corrosion, and broad temperature variations. 

They often display high strength-to-weight ratios, flexibility, radar absorption, and flutter suppression, which make them especially useful for aviation applications in which stability and reduced weight are vital. Ceramic matrix composites, braided composites, and intermetallic alloys are especially useful high-temperature materials for aviation applications.

Ceramic Matrix Composites

In ceramic matrix composites (CMCs), the constituent materials are blended in a grid of ceramic fibers for a particularly tough and durable material. CMCs can withstand extremely high temperatures and are used to enhance overall aircraft structural performance. They are lighter than nickel superalloys, with greater temperature tolerance and significant resistance to pesting and fatigue. 

Braided Composites

As the name implies, braided composites are composed of interwoven strands of the base materials. Technological advancements have largely automated the manufacturing process, making braided composites more popular than ever. They are especially valuable for their strength, toughness, and resistance to damage. 

Intermetallic Alloys

In addition to composite materials, intermetallic alloys have found a niche in the aviation industry. Intermetallic alloys consist of multiple metals, often nickel and titanium, blended to form an alloy with solid crystalline structure. The specific properties of intermetallic alloys depend largely on the constituent metals, but those used in aviation tend to have high melting points, superior thermal conductivity, low density, and high resistance to corrosion and oxidation.

High-temperature composites and intermetallic alloys can be tailored to meet the needs of a broad range of applications in the aviation industry, particularly for insulation and hardware such as high-temperature gaskets.

High-Temperature Insulation

High-temperature insulation is crucial for the protection of sensitive aircraft components from temperature fluctuations and high levels of compression. This specialized insulation can be found in a broad range of applications within the aviation industry. 

Aircraft Interiors

High-temperature insulation is a key component of temperature control systems in aircraft interiors. It is often used to insulate air ducts and tubing, as well as paneling for walls, ceilings, and overhead storage compartments. 

Thrust Reversal Systems

Thrust reversal systems help to slow the aircraft by rerouting engine exhaust toward the front of the vehicle, creating air resistance and reducing the speed of the aircraft. Insulation must be used to protect surrounding components from the extreme heat of the released exhaust.

Electrical Components and Batteries

Many electronic components used in aviation are highly sensitive and must therefore be protected from heat and electromagnetic interference. High-heat insulation protects electronic instruments, the ignition battery, and auxiliary power units from extreme temperatures and interference. In addition, high-heat insulation helps to insulate against electrical fires for enhanced aircraft safety.

Black Boxes

High-temperature insulation is also used to protect the black boxes of aircraft to ensure they can withstand extreme conditions that may occur during an emergency. The exterior armor of a black box must be composed of a highly durable and thermally efficient insulating material, so that it can be recovered in the event of an unexpected emergency

High-Temperature Gaskets

Similar to high-temperature insulation, high-temperature gaskets are critically important to the safe operation of aircraft. They ensure an airtight seal between mating surfaces to insulate against leaks. Due to the extreme temperatures in which aircraft equipment operates, high-temperature gaskets are useful for a variety of applications. 

Window gaskets are installed to seal the glass and sheet metal around aircraft windows, and must withstand extreme temperature fluctuations and pressure at high altitude. Similarly, fuel door gaskets are used to seal the fuel system from harsh external environments. To be fully effective, fuel door gaskets must also be resistant to corrosion from the harsh chemicals in jet fuel. 

High-temperature gaskets are also widely used to seal exterior aircraft components, such as the wings and other surfaces. In this setting, the gaskets must withstand extreme pressure, high speeds, and the extremely low temperatures of the upper atmosphere.

High-Temperature Aerospace Parts from RCF Technologies

At RCF, we understand that aircraft components and insulation must be composed of materials that can withstand the high temperatures common in aerospace applications. To this end, we have developed our specialized Rishon® composite material, which exhibits a number of characteristics that make it particularly useful in the aerospace industry. The hallmark properties of Rishon include:

  • Broad Temperature Range
  • Fireproof
  • Chemical Compatibility
  • Speedy Vulcanization Process
  • Sound and Vibration Absorbent
  • Heat and Flame Insulator
  • Electrical Conductivity
  • Low Outgassing

For more than 40 years, RCF Technologies has worked closely with our customers in aviation to design and produce industry specialized seals, couplings, ducting, and gaskets for commercial aircraft. Our broad range of experience in high-temperature applications extends to aerospace, automotive, marine, and petrochemical applications. 

To learn more about our high temperature components and solutions, contact us today!

All About Electrically Conductive Materials

As most people are aware, metals serve as excellent conductors of electricity, while non-metals (such as plastics and rubbers) do not. Electrical conductivity—or lack thereof—make these two types of materials generally suited for different use cases in the industrial sector. When choosing a manufacturing material for an electrical or electronic device, it is important to consider its electrical properties, including its conductivity, to ensure the end product functions as intended.

The following blog post serves as a guide to electrically conductive materials, outlining what causes their key property, the types available, how they relate to manufacturing, and how to turn a typically non-conductive material into a conductive one.

What Causes Electrical Conductivity?

Manufacturing materials vary in the number (one to eight) of valence electrons present in the outer shell of their atoms. In general, the lower the number, the more conductive the material (usually a conductor) and, the higher the number, the less conductive the material (usually an insulator).

Most metals have between one to three valence electrons, which allows the electrically charged subatomic particles to dislodge and mobilize easily. The free movement of electrons results in the passing of a charge—i.e., the conduction of electricity. In contrast, rubber and plastic materials typically have few, if any, free electrons, making them poor electrical conductors but excellently suited for insulating applications.

Examples of Electrically Conductive Materials

Many of the most highly conductive materials are metals. The three metals with the highest electrical conductivity are:

  1. Silver
  2. Copper
  3. Gold

Each of these metals has one valence electron. Aluminum is the next most conductive metal, despite having three valence electrons. Although silver and gold offer greater conductivity than copper and aluminum, respectively, the latter materials are more commonly used due to their lower cost and broader availability.

The Impact of Electrical Conductivity on Manufacturing

The electrical properties of a material influence how it is used in electrical and electronic devices. For example:

  • Conductors—highly conductive materials (e.g., metals such as silver, gold, or copper)—are used for manufacturing electrical wires and cables
  • Insulators—materials with poor electrical conductivity (e.g., rubber or plastic)—are used for making insulation and other electrical protection products
  • Semiconductors—materials that are neither good nor bad conductors of electricity (e.g., silicon)—are widely used to make integrated circuits for computers, phones, TVs and many other electronic devices

How to Make Non-Conductive Materials Conductive

As an alternative to metals, product manufacturing companies may also use a typically non-conductive material, such as a fabric or elastomer, that has been altered to have enhanced electrical conductivity. Material manufacturers can convert a non-conductive substrate into an electric conductor by employing a specialized technique that integrates electrically conductive additives into the base material.

Electrically Conductive Products From RCF Technologies

At RCF Technologies, we leverage our proprietary material—Rishon®—to create a wide range of electrically conductive products, such as couplings and seals. Although Rishon is naturally non-conductive, we can incorporate minute quantities of additives that enhance its conductivity without increasing its weight. To learn more about our electrically conductive products, contact us today.