An O ring is a torus shaped ring with a circular cross-section that is used as a mechanical seal or gasket. It can be made using various materials like elastomers, thermoplastics such as PTFE and metal. The primary function of an O-ring is sealing in static and dynamic applications. 

Rubber O rings or Elastomeric O rings are used as an O ring Seal to prevent the loss of fluid or gas. A typical seal assembly consists of a gland that contains and supports the O ring. 

Material Selection Criteria for Rubber O-rings

The choice of your base elastomer or material is made based on two primary factors:

1. Operating Temperature

During compression, a seal changes from its original state and overtime, with exposure to excessive temperatures, beyond a material’s limit, there will be a loss in the elastic memory of the seal. This will result in leakage and system failure. 

      2. Media that needs to be sealed

All elastomers undergo physical or chemical changes when they come in contact with aggressive media. The limit of permissible volume change – shrinkage or swelling – that an elastomer can tolerate, will determine the material of choice for an O-ring seal.

 

What are the materials used in making Rubber O-rings?

In the following points we will go through the various materials or basic elastomers that are used for Rubber O-ring Seals. Depending on requirements of heat resistance, chemical resistance and other physical influences, the base elastomer and the hardness of the finished product (O-ring Seal) are determined. 

• Acrylonitrile-Butadiene (NBR)

Nitrile rubber is the general term for acrylonitrile-butadiene copolymer. The physical properties of the copolymer vary greatly based on the content of acrylonitrile in it. NBR is a versatile compound as it has good mechanical properties and high wear resistance. It is resistant to heat up to 100 deg. C. However, it is not recommended for outdoor applications, as it is not resistant to ozone, weather and atmospheric aging. 

• Styrene Butadiene Rubber (SBR)

Styrene Butadiene Rubber (SBR) O-rings are used in highly abrasive conditions. SBR is known to have good physical properties such as impact strength, good resilience, tensile strength, and excellent abrasion resistance with favorable ageing characteristics. The weaknesses of SBR are that it requires reinforcement and has sub-par low temperature resistance. 

• Ethylene Propylene Diene Monomer (EPDM)

EPDM copolymer is made of Ethylene and Propylene. They are particularly used in outdoor applications and in brake systems that use fluids having glycol base. They have good low temperature resistance and are also resistant to ozone, steam, weather and atmospheric ageing. They are used very often in Automobile Industries. They are not compatible with mineral oil products such as oils, greases and fuels.

• Chloroprene Rubber (CR)

Chloroprene rubber was the first synthetic rubber that was developed commercially. It exhibits good ozone, ageing and chemical resistance. It has good mechanical properties over a wide temperature range from -40 deg C to 121 deg C. It also shows good resistance to high aniline point oils. 

• Silicone Rubber 

Silicone is a polymer of silicon, carbon, hydrogen and oxygen. It is generally stable and non-reactive, and can maintain its properties across a wide temperature range. This material is used when the retention of the initial shape of the product is required. 

• Fluoroelastomer (FKM)

Fluoroelastomers have excellent resistance to mineral oils, greases, certain aliphatic and aromatic hydrocarbons, ozone, weather and aging. They are also resistant to certain solvents, chemicals and high temperatures. Due to their resistance to petroleum based greases and oils, they are widely used in Oil & Gas, Chemical, Automotive and Aerospace applications. FKM Compounds come under the category of High Performance Elastomers. 

• Fluorosilicone (FVMQ / FSL)

Fluorosilicone rubber is a type of silicone rubber with the fluorine group attached to the main polymer chain. As a result, FVMQ seals are more stable with resistance to a wide range of oils, acids, fuels and non-polar solvents. FVMQ also has good compression set resistance and maintains excellent tensile strength. 

• Hydrogenated Nitrile (HNBR)

This is created by the Hydrogenation of NBR. HNBR has superior mechanical characteristics such as high strength, higher heat resistance and wear behavior in dynamic applications. It also helps to reduce extrusion.

• Perfluoroelastomer (FFKM)

FFKM is a champion polymer in sealing applications. It has the widest operating temperature range than any other compound due to the presence of more fluorine than even FKM elastomers. It is also resistant to a wide variety of chemicals and solvents such as hot amines, sour gases and hydrocarbons. 

• Tetrafluoroethylene Propylene (FEPM)

Tetrafluoroethylene Propylene (FEPM) is a high performance elastomer composed of tetrafluoroethylene and propylene. It is compatible with a wide variety of chemicals such as bases, amines, water, engine oils, ozone and alcohols. But it is important to note that it is not compatible with chlorinated and aromatic hydrocarbons and even acetone. 

What are the applications or uses of Rubber O-rings?

• Aerospace:

Sealing Systems: Used in aircraft engines, fuel systems, and hydraulic systems to ensure reliable sealing under extreme temperatures and pressures.

• Automotive:

Engine Components: Provide reliable seals in fuel injectors, coolant systems, and turbochargers.

Transmission Systems: Used in automatic and manual transmissions to prevent fluid leaks and ensure smooth operation.

• Oil and Gas:

Used in valves, pumps, and flanges to prevent leaks and maintain system integrity under high temperatures and aggressive chemicals.

• Chemical Processing:

Pumps and Valves: Provide chemical resistance and prevent leaks in pumps and valves handling aggressive chemicals.

• Pharmaceutical and Food Industries:

Sterile Environments: Used in equipment that requires strict hygiene standards, such as mixers, pumps, and filling machines.

• Semiconductor Manufacturing:

Vacuum Systems: Essential for maintaining vacuum integrity in semiconductor manufacturing processes.

Chemical Resistance: Provide reliable sealing in the presence of aggressive chemicals used in semiconductor fabrication.

What are the properties of Rubber O-rings?

Rubber O-rings are versatile sealing components with a range of properties that make them suitable for various applications. Here are some of the key properties of rubber O-rings:

1. Elasticity and Resilience:

• Elasticity: Rubber O-rings can return to their original shape after deformation, allowing them to create an effective seal by filling gaps.
• Resilience: They can withstand repeated cycles of compression and decompression without significant loss of performance.

2. Compression Set Resistance: 

Rubber O Rings have a lower compression set enabling good sealing performance. This means that the level of deformation is less under a compressive load. 

3. Chemical Resistance:

Different rubber materials offer varying levels of resistance to oils, solvents, chemicals, gases. 

• Nitrile (Buna-N): Good resistance to oils, fuels, and other petroleum-based fluids.
• Viton (FKM): Excellent resistance to high temperatures, chemicals, and oils.
• EPDM: Good resistance to water, steam, and weathering, but poor resistance to oils and fuels.

4. Temperature Range:

Rubber O rings can operate in a wide variety of temperatures, depending on the material:

• Silicone O Rings & FVMQ O Rings can operate at temperatures as low as -70° C
• FFKM O Rings can operate at temperatures as high as +315° C

5. Hardness:

Hardness is measured on the Shore-A scale, typically ranging from 35 to 95. The appropriate hardness depends on the application, with softer O-rings providing better sealing on uneven surfaces and harder O-rings offering better resistance to extrusion.

6. Tear and Abrasion Resistance:

Rubber O rings have varying degrees of resistance to tearing and abrasion. Materials like Polyurethane have excellent resistance to abrasion, while others like Silicone are more prone to tearing.

7. Permeability:

Permeability refers to a material’s ability to resist gas or liquid to pass through it. The extent of Permeability of Rubber O rings can vary depending on the type of the elastomeric material. 

Fluorocarbon (FKM) offers very good permeability to gases, and is also highly resistant to a wide variety of harsh chemicals. As a result, it’s the ideal choice in Chemical Processing Industries.

8. Electrical Insulation:

Rubber O-rings are generally good electrical insulators, which can be beneficial in certain applications.

9. Ageing and Weather Resistance:

This refers to the ability of O Rings to resist ageing due to exposure to Ozone, UV Light, and environmental conditions:

• EPDM: Excellent resistance to Ozone, UV Light and Weathering.
• Silicone: It also offers excellent resistance to Ozone and Weathering.

10. FDA Compliance:

Special rubber compounds and Some specific elastomeric grades in Silicone, EPDM can be formulated to be compliant with US FDA regulations for use in food, beverage and pharmaceutical applications.

11. Cost Effectiveness:

Elastomeric O-rings are generally cost-effective, offering a high performance-to-cost ratio. They are easy to manufacture and replace, making them a practical choice for many sealing applications.

 

What are Engineering Plastics?

Engineering Plastics are high performance synthetic materials with high durability and heat resistance. These engineering plastics are used in industrial components that require superior functionality. The high performance plastics are specifically designed to have better characteristics than general purpose or commodity plastics. These properties may include better mechanical, electrical, and thermal properties; improved chemical and ultraviolet light resistance; and biocompatibility for food packaging applications.

In this article, we will go through the difference between commodity plastics and engineering plastics, the properties of engineering plastics, its uses and applications etc. 

What is the difference between Commodity Plastics and Engineering Plastics? 

Commodity plastics or General Purpose Plastics are used in high volume applications where technical requirements are not stringent. These commodity plastics are relatively inexpensive to produce and possess weaker mechanical properties. 

Some examples of Commodity Plastics include:

• Polypropylene (PP)
• Polyethylene (PE)
• Polyvinyl Chloride (PVC)
• Polystyrene (PS) etc. 

The technologically advanced engineering plastics possess greater mechanical and thermal properties. They have the capability to replace traditional engineering materials such as ceramics and metals in specific cases because of their higher performance and enhanced durability. 

What are the different types of Engineering Plastics?

There are various types of engineering plastics. These may include:

• Poly tetra fluoro ethylene (PTFE).
• Reinforced Poly tetra fluoro ethylene (RPTFE).
• Poly chloro trifluoro ethylene (PCTFE).
• Poly ether ether ketone (PEEK).
• Reinforced Poly ether ether ketone (RPEEK).
• PolyImide (PI).
• PolyOxyMethylene (POM).

What are the Properties of Engineering Plastics?

1.Abrasion Resistance

Abrasion resistance is the ability of a material to resist the loss of volume from its surface due to rubbing, sliding or scraping. Engineering plastics have a low coefficient of friction compared to metals in the same or similar applications. They also possess self-lubrication properties, making them ideal for extended wear and use in load-bearing applications.

2.Chemical Resistance

Chemical resistance describes the ability of a material to withstand a chemical attack for a specific period without significant deterioration of its performance properties. Some types of engineering plastics possess the ability to resist corrosive chemicals without the loss in their form and structure. 

3.Dimensional stability

Dimensional stability is a measure of a material’s ability to retain its fit, form, and functional properties throughout its lifecycle. Engineering Plastic parts are used in demanding applications and are subject to high levels of mechanical stress. These plastic parts also possess the advantage of being lighter in weight compared to metals. For additional dimensional stability, the thermoplastic can be reinforced with glass fibers or other fillers. 

4.Electrical properties

Electrical properties are related to a material’s ability to conduct or insulate electrical currents. Electrical conductivity and resistivity are the two critical electrical properties of engineering plastics. Most engineering plastics are poor electrical conductors which makes them ideal for applications where electrical insulation is desired, such as in various electronic and wiring applications.

5.Thermal Resistance

Thermal resistance refers to a material’s ability to resist changes in its form and structure under varying temperatures. Different engineering plastics possess different levels of thermal resistance, hence it is important to choose the right grade for a particular application. Engineering Plastic like PEEK can be used in high-temperature applications up to 250 deg. C, and PTFE can be used in low-temperature applications as low as -150 deg. C 

6.Flammability

Flammability can be defined as a material’s ability to catch fire. Depending on the type of engineering plastic, the material’s extent of flammability may vary. For eg. materials such as PEEK or PPS are specifically formulated to provide flame resistance and prevent ignition. Polytetrafluoroethylene (PTFE) is a non-flammable engineering plastic. It is a strong, waxy and tough resin produced by the polymerization of tetrafluoroethylene. This engineering plastic is used in high temperature applications, and is stable in conditions up to 500 deg. F

7.Food compatibility

Food compatibility refers to a material’s safety for use when it comes in contact with food. Since engineering plastics are heat resistant, chemical resistant and wear & tear resistant, the material’s form and chemical structure does not change when it comes in contact with food at different temperatures. Of all the engineering plastics, PTFE and PEEK are the most compatible in food and beverage applications. 

8.Impact strength

Impact strength is the ability of a material to absorb energy during plastic deformation. The toughness of plastics is measured by their resistance to impact. Nylon and PEEK have the best impact strength.

9.UV Resistance

Amongst all the Engineering Plastics, PTFE is known to have the best UV Resistance because of the strong carbon-fluorine bonds found in the material. 

What are the Uses and Applications of Engineering Plastics?

ISMAT’s Novum Series of Engineering Plastics are primarily used in industries, as seals and gaskets. They are used across various industries like:

• Food & Beverage
• Automotive 
• Oil & Gas
• Aerospace
• Chemical 
• Medical & Pharmaceutical
• Drinking Water or Potable Water Applications

Engineering plastics can be used to manufacture the following components:

• Valve Seats
• Stem Seals
• Valve sleeves
• Envelope gaskets
• Chevron packings
• O-rings
• Guide rings
• Spring energized seals
• Washers
• Gaskets
• Wear rings
• Piston seals
• Custom designed parts

What is the Process of Manufacturing Engineering Plastic Components?

At ISMAT, manufacturing of the engineering plastic components is done under the following steps:

• Cold compression moulding

Compression moulding is the process of manufacturing complex composite components with the application of pressure under varying temperatures – depending on the composite. Cold compression moulding is a curing process for thermoplastics, where the curing takes place at room temperature. 

• Sintering

Once the moulding process is completed, the components are then taken for Sintering. 

Sintering is a heat treatment process where a material is converted to a solid mass with the application of heat, below the material’s melting point.

• Machining 

Once the component has been cured, it is machined according to the specific dimensions.

• Deflashing

Deflashing involves the removal of excess plastic material from its body surface. Deburring is a type of deflashing technique that removes sharp edges or burrs from plastic materials, leaving the material with smooth edges and fine finished surface.

• Quality Inspection

Quality Inspection is the process of evaluating and verifying if the inspected materials and products conform with the specified requirements. Quality inspectors are a critical part of ensuring that products are of high quality and produced in compliance with the client’s standards.

Summary

Engineering Plastics possess greater physical and chemical properties in comparison to other commodity plastics and metals. These materials can be used in various industrial applications due to factors such as: superior abrasion resistance, thermal resistance and chemical resistance. Engineering plastics may be used in the manufacture of Seals, Valve seats, Gaskets, Washers and other custom molded components. Get in touch with us to learn more about engineering plastics. Follow us on LinkedIn for more such articles. 

Industrial Sealing Solutions need to be precisely engineered, because they are often used in environments with aggressive chemicals and extreme temperatures. One elastomer that stands as a champion for such environments is Vertex F or Perfluoroelastomer (FFKM) 

FFKM, often known as the “Rubber Teflon,”  is a unique elastomeric polymer that thrives in the most challenging environments, due to its fully fluorinated backbone derived from poly(tetrafluoroethylene) or PTFE. Vertex F (FFKM) contains higher amounts of fluorine than standard FKM, resulting in higher temperature ratings (up to approximately 325°C/617°F). There are also some FFKM grades that have excellent resistance to low temperatures up to -40 deg C as well.

ISMAT offers a comprehensive range of VERTEX F perfluoroelastomer compounds. These compounds are available in various forms such as molded and vulcanized O-Rings, X-Rings, Lipseals, and custom parts, that are used in industries across: Oil & Gas, Aerospace, Automobile etc. 

Let’s dive deeper into why exactly Vertex F or FFKM is better than other compounds?

Features and Benefits of VERTEX F / FFKM:

Chemical and Temperature Resistance:

Withstanding the most aggressive chemicals and extreme temperatures, VERTEX F series materials excel where others falter, ensuring reliability in the harshest conditions.

Long Service Life:

Reduced downtime and maintenance requirements translate to lower total cost of ownership, making VERTEX F series materials a cost-effective choice in the long run.

Low Compression Set:

Enhanced sealing force and reduced leakage over extended periods result from low compression set, ensuring consistent performance over time.

High Purity:

Controlled environment room production ensures high purity and precision in every component, meeting the most stringent quality standards.

Precision Manufacturing:

Flashless, wasteless tool design concepts ensure high precision and quality with short lead time. 

ISMAT strives to provide these industrial sealing solutions to their customers through:

Engineering Expertise:

ISMAT’s team of engineering experts collaborates closely with clients to tailor solutions for their specific applications. From conceptualization to production, ISMAT ensures every aspect is optimized for performance and reliability.

Decades of Experience:

With decades of experience in solving complex challenges, ISMAT brings a wealth of knowledge to the table. Combined with cutting-edge manufacturing and tooling technologies, ISMAT is the go-to partner for enhancing application performance and reducing total cost of ownership.

Versatile Manufacturing:

From high-specification O-Rings to intricate custom components, ISMAT’s manufacturing capabilities cover a broad spectrum. Whether it’s micro-scale seals or large-diameter solutions, ISMAT delivers precision without compromise.

In conclusion, the VERTEX F series by ISMAT represents the pinnacle of FFKM innovation, offering unmatched reliability, longevity, and performance in the most demanding environments. With ISMAT as your development partner, rest assured that your sealing challenges will be met with precision, expertise, and unwavering commitment to excellence.