Materials Descriptions

Material Description

Silicone Rubber (VMQ)
Styrene-butadiene rubber (SBR)
Polyacrylate Rubber (ACM)
Nitrile (NBR, Buna N)
Natural Rubber (NR)
Hydrogenated Nitrile (HNBR)
Fluorosilicone (FVMQ)
Flourocarbon Rubber (FKM)
Ethylene Acrylic Rubber (EAM)
Ethylene-Propylene Diene (EPDM)
Butyl Rubber (IIR)
Chloroprene Rubber (CR)
Polyurethane Rubber (AU/EU)

 
 

Silicone Rubber (VMQ)

Silicone rubber is an inorganic synthetic elastomer that is vulcanized creating a crosslinked silicon based polymer that is reinforced with fillers. A superior combination of mechanical and chemical properties can achieve a wide range of demanding applications. Excellent weathering and heat/cold resistance with a wide temperature spectrum of -76° to 480° F. Even higher temperature resistance can be achieved with special formulations.

Silicone rubber can be found in a variety everyday products and applications. Household and consumer products such as cookware, food storage, textile, footwear, electronics, sporting goods and hardware all utilize silicone rubber to some degree. Colorants can be added to silicone to produce virtually any color.

Because of its excellent physical and chemical performance and ease of manufacture it is commonly used in a variety of industrial, automotive, healthcare/medical, electric/electronics aviation and construction applications.

Hardness: 10-100 – Shore A
Tensile Strength: 0 – 1,500 PSI
Elongation: 100% to 1,100%

Chemical Structure:

 
 
 

Styrene-butadiene rubber (SBR)

Styrene-butadiene rubber is a family of synthetic rubbers derived from the monomers styrene and butadiene. This material has similar physical properties to natural rubber, but is more cost effective alternative. With excellent abrasion resistance, crack resistance, and water resistance this material is extensively used in the production of tires, gaskets/seals, grommets, hydraulic brake seals (non-petroleum based), diaphragms, and a variety of plumbing applications.
SBR is not recommended for exposure to fat, acids, ozone, hydrocarbons (such as oil, fuel), and solvents. SBR swells and is weakened by contact with hydrocarbon oils and will degrade with long term exposure to oxygen and ozone.

Hardness: 30-100 – Shore A
Tensile Strength: 500 – 3,000 PSI
Elongation: 450% – 600%

Chemical Structure:

 
 
 

Polyacrylate Rubber (ACM)

Polyacrylate is a specialty copolymer that has excellent resistance to high heat (max. 350° F) and petroleum fuels and oils. Excellent weathering and ozone resistance make it a prime material choice for automotive transmission and general industrial gasket/seal applications. Polyacrylate demstraight greater heat resistance compared to Nitrile, but is inferior for low temperature use – compared to other polymers.

Limitations of Polyacrylate makes it prone to attacked by water, alcohol, glycol and aromatic hydrocarbons.

Hardness: 40–90 Shore A
Tensile Strength: 2,500 PSI
Elongation: 100 – 450%

Chemical Structure:

 
 

Nitrile (NBR, Buna N)

Nitrile rubber is a family of unsaturated copolymers of butadiene and acrylonitrile monomers. It is a general purpose copolymer that exhibits good mechanical properties and high wear resistance compared to similar elastomers. Used in general industry, transportation and aerospace this synthetic rubber is resistant to petroleum based oil, hydrocarbon fuels, and a variety of chemicals. These properties make nitrile a good candidate for hoses, fuel systems, seals, grommets, floor mats, lab gloves, and protective ware. Nitrile is less likely to trigger allergic reactions compared to natural rubber.

Limiting factors of Nitrile are poor long term exposure to ozone sunlight and weather.

Hardness: 20-95 Durometer – Shore A
Tensile Strength: 200 – 3,500 PSI
Elongation: 350% – 650%

Chemical Structure:

 
 

Natural Rubber (NR)

Natural rubber is an elastic latex material harvested from Hevea and Ficus trees. In its vulcanized form natural rubber has excellent mechanical properties exhibiting high tensile strength and high abrasion/tear resistant properties. Natural rubber is resistant to most organic salts, acids, alcohols and alkali solutions. This material is suited for light to medium commercial applications where exposure to severe temperature and chemical conditions are limited.
The transportation industry utilizes natural rubber extensively in tire manufacture, and a variety of vibration and sealing components. Other applications include hoses, foot-ware, toys, balloons, and vibration adsorption. Medical use has been reduced because of allergic concerns.

Hardness: 30-95 – Shore A
Tensile Strength: 500 – 3,500 PSI
Elongation: 300% to 900%

Chemical Structure:

 
 

Hydrogenated Nitrile (HNBR)

Hydrogenated Nitrile is made by selective hydrogenation of the NBR butadiene groups. HNBR is recognized for its strong physical strength for long term exposure to heat, oil and chemicals, as well as, cost effectiveness. HBNR is commonly used in place of nitrile where temperature is a factor. It fills the gap between NBR’s and FKM’s. The unique properties of HNBR allow it to be used over a wide service temperature from -40° to 320° F. Overall, HNBR elastomers have excellent resistance to standard automotive grade fluids and a variety of industrial chemicals. The cost advantage for demanding applications requiring superior physical properties coupled with fuel, oil and chemical resistance makes it an excellent polymer choice.
HNBR has poor electrical and flame resistance properties. It is attacked by some oxygenated solvents and aromatic hydrocarbons.

Hardness: 30-95 Durometer – Shore A
Tensile Strength: 1,500 – 3,500 PSI
Elongation: 90% – 550%

 

Fluorosilicone (FVMQ)

Fluorosilicone has better fuel and oil resistance than other silicone rubbers. Physical properties of fluorosilicone such as tensile strength, elongation and tear resistance are comparable to general purpose silicone rubbers. Generally, this material is designed for static sealing applications because of poor abrasion resistance. Fluorosilicone has a temperature range of -75 to 450° F. Primarily used in aviation and automotive fuel systems.

Permeability to gases and abrasion resistance are poor. Exposure to brake fluids, ketones, amines, adelhydes is not recommended.

Hardness: 35-80 – Shore A
Tensile Strength: 200- 1,500 PSI
Elongation: 100% – 480%

Chemical Structure:

 

Flourocarbon Rubber (FKM)

Fluorocarbon Rubber is a specialized compound with excellent high heat, oil resistance and low compression set. Flourocarbon rubber also has excellent abrasion resistance and the ability to hold a seal under hard vacuum. Gas permeability is very low and similar to that of butyl rubber.
With a service life upwards of 392° F for prolong periods of time, and repeated thermal cycling, makes this an ideal sealing material for aviation engine components. Generally, fluorocarbon elastomers can be custom manufactured for applications in the transportation, aerospace, and petrochemical industries.

Flourocarbon elestomers are not suitable where low temperature flexibility is required. Vulnerable to exposure with ketones, amines, esters and alkali.

Hardness: 50 – 95 Shore A
Tensile Strength: 500 – 2,000 PSI
Elongation: 400% to 500%

Chemical Structure:

 

Ethylene Acrylic Rubber (EAM)

Ethylene Acrylic rubber is a copolymer of ethylene and methyl acrylate with a small amount of carboxylic acid. Ethylene Acrylic physical properties make it a highly durable, low compression set rubber with good resistance to high heat aging, mineral oil, UV and weathering. Also exhibits good low temperature flexibility and vibration dampening characteristics. Typical service temperature range is -22° to 302° F.

Generally not recommended for applications where exposure to fuel, brake fluid, aromatic hydrocarbons or phosphate esters are likely.

Hardness: 40 – 85 Shore A
Tensile Strength: 500 – 3,000 PSI
Elongation: 200% to 850%

Chemical Structure:

 

Ethylene-Propylene Diene (EPDM)

A synthetic rubber with very good performance utilized in a wide range of applications. Mainly used in seals for plumbing, potable water systems (certifiable to NSF std. 61), roofing membranes, wide-ranging automobile applications (door, trunk and window seals), heating systems, hoses and various industrial products. Capable of being compounded with high filler loads.

Because of a stable saturated polymer backbone construction it is resistant to heat, oxidation, ozone and UV weather aging. It is a non-polar elastomer with decent electrical resistivity and resistance to polar solvents like water, acids, alkalies, phosphate esters, and many ketones and alcohols. Able to achieve a wide temperature range from -58° to 320°F.

EPDM’s are compounded with sulfur or peroxide cure systems. Peroxide cure compounds are suitable for high temperature and typically have better compression set performance.

EPDM compounds are not recommended for exposure to petroleum oils, fuel, mineral oil and aromatic hydrocarbons.

Hardness: 30 to 95 – Shore A
Tensile Strength: > 2,000 PSI
Elongation: 100% to 600%

Chemical Structure:

 

Butyl Rubber (IIR)

Butyl rubber is a synthetic rubber comprised of a copolymer of isobutylene with a lesser amount isoprene. The primary benefits of butyl rubber are superior gas/moisture impermeability, weather resistance, ozone, flexibility and vibration dampening. These properties make it an excellent choice for durable inflatables, innerliners for tires, inflatable sporting goods, aquatic liners and a variety of mechanical products.

Butyl is generally not recommended for contact with petroleum oils and liquids.

Hardness: 40 to 90 – Shore A
Tensile Strength: 500 – 3,000 PSI
Elongation: 850%

Chemical Structure:

 

Chloroprene Rubber (CR)

Chloroprene, commonly known as Neoprene®, was originally developed as an oil resistant synthetic rubber with a similar molecular structure to that of natural rubber. It is a good general purpose rubber with excellent balance of physical and chemical properties. Generally good mechanical strength balanced with resistance to chemicals, ozone and weathering. Chloroprene has moderate fuel and oil resistance.

Chloroprene is highly resistant to commercial refrigerants such as Freon® and ammonia. This makes Chloroprene an excellent material choice for use in refrigeration systems.

Not recommended for exposure to strong oxidizing acids, esters, ketones, chlorinated aromatic and nitro hydrocarbons.

A wide range of applications include cable/wire jacketing, automotive (belts, hoses, motor mounts, CV boots, braking and steering systems) general industrial, construction, refrigeration, textile and sporting goods industries. Operational temperature range from -40° to 250° F

Hardness: 40 – 90 (Shore A)
Tensile Strength: 500 – 3,000 PSI
Elongation: 100% to 800%

Chemical Structure:

Neoprene® and Freon® are registered trademarks of DuPont

 
 

Polyurethane Rubber (AU/EU)

There are two main chemical compounds of molded polyurethane; polyester (AU), and polyether (EU). The physical characteristics of these polymers are such that they exhibit excellent tensile strength, abrasion and tear resistance.

Polyurethane is a versatile material that provides the elasticity of rubber with the strength of metal and ceramic. Polyurethanes performance is superior to that plastic, rubber and metal because its capability to resist abrasion, heat, oil, solvents and a variety of chemicals. These properties make it a material of choice for engineers designing products for high load and stress applications. Permeability is good and similar to that of butyl rubber

Polyurethane performs well in a temperature range of -60° to 175° F. Not compatible with esters, ketones, alcohols, acids, alkalis, amines, warm water and steam.

Hardness: 35-95 – Shore A
Tensile Strength: 500- 6,500 PSI
Elongation: 250% – 900%

Chemical Structure: