A Comprehensive Guide to Rubber Gasket Materials

by Mike H. Marketeer

What are Gaskets?

Like mechanical seals, gaskets are designed and manufactured to fill the gap between two mating surfaces, both inside and outside a fluid processor or similar equipment.


The intended purpose of gaskets is to stop fluids from seeping out of the equipment, thereby saving precious processing fluid and the harm it may cause to the environment of both the processor and the personnel in its proximity.

Classification of Gaskets

Gaskets may be set apart by material, function, application, or purpose. However, the fact that they’re cut from a different, flexible cloth is what makes them most different from conventional mechanical seals.


Let’s brush over the following types:


·         Cork Gaskets

·         Non-asbestos Gaskets

·         Rubber Gaskets

·        Cork Gaskets

Natural cork is mixed with elastomer to make these gaskets resistant and suitable for applications involving fuel, oil, and solvents.


·        Non-Asbestos Gaskets

Compressed fiber with elastomer bindings gives non-asbestos gaskets the tenacity to resist attacks from acids, water, lubricants, and steam produced from mechanical seal faces during processing.


·        Rubber Gaskets

As far as gasket solutions go, rubber is the most common material of all. The many elastomer options in this category make it suitable for all applications, from feedwater pumps to pipes to mixers and more.


Let’s take a more detailed look at some of the materials offered in this industrial sealing solution.

1.    Hypalon

Hypalon is an elastic material made from chloro-sulfonyl-polyethylene. The gaskets made from this textile are mostly used as external mechanical seals due to their UV-resistant capabilities.


Apart from not giving into sun damage, this material is fairly resistant to lubricants, processing components of a chemical nature, and can take temperatures as low as -22°F and as high as 356°F.


Defining Characteristics

·         Durometer Rating: 65

·         Best Against Leakage: All fluids

·         Best Resistance: High temperatures.

·         Mild Resistance: Lubricants and component chemicals.

·         External Merits: Immune to weathering, ozone, and UV rays.

·         Standard: Smooth finish on one or both sides.

2.    Silicone

Silicone is a manmade elastomer known for its anti-adhesive and electrical insulating capabilities. Like Hypalon, its gaskets are also used as exterior mechanical seals due to their resistance to the harmful effects of extreme weather conditions.


Among the many benefits provided by the application of silicone gaskets is their ability to remain flexible under temperatures ranging anywhere from -94°F to 482°F.


Defining Characteristics

·         Durometer Rating: 60

·         Versatility: Customizable to a wide range of thicknesses and lengths.

·         Best Resistance: Heat and electric current.

·         External Merits: Immune to weathering and oxidization.

·         Standard: Silicone has many forms including, commercial, FDA-approved, medical, flame-resistant, high-temperature, and conductive gaskets.

3.    EPDM

EPDM, short for ethylene propylene diene monomer, is a synthetic rubber derived from oil and natural gas whose main selling point is durability. As a copolymer, this material is both viscous and elastic and retains its integrity better than any naturally derived rubber gasket.


What Hypalon can’t do, EPDM more than makes up for with its resistance to ketones, alkalis, and acids. However, the same can’t be said for temperature. EPDM gaskets are recommended for medium sealing applications because they’re suited to the comparatively milder temperatures of -4°F - 158°F.


Defining Characteristics

·         Durometer Rating: 60

·         Best Feature: Durability

·         Best Resistance: Ketones, alkalis, and acids.

·         External Merits: Immune to ozone and weathering.

·         Standard: Most common iterations are commercial grade and FDA-approved EPDM.

4.    Neoprene

Neoprene is an elastomer that’s derived by polymerizing chloroprene. Gaskets made from this material can fit just about any mating surface, proving themselves to be a formidable plug against any and all sorts of leakage, hazardous or otherwise.


Due to being a low-cost mechanical seal, neoprene gaskets are the first option for many manufacturers, in search of a seal that can withstand lubricants, process components, sun damage, ozone, extreme temperatures, fluids (gas and liquid), pressure, and the general weather. Indeed, some variations of neoprene can hold under temperatures as low as -22°F and as high as 158°F.


Defining Characteristics

·         Durometer Rating: 60

·         Best Resistance: lubricants, process chemicals, fluids, and pressure.

·         External Merits: Immune to the environment.

·         Standard: Forms include commercial, medium, and high-grade neoprene.

5.    Gum

Gum is derived from the latex of certain trees, from where it’s refined and made ready for different applications. This natural rubber is preferred for its elasticity and tenacity in specific conditions, mainly those requiring water resistance.


Natural rubber gaskets may not be completely immune to lubricants, undiluted strong acids, alkalis, and hydrocarbons. However, their resistance to dilute acids, alcohol, ketones, and organic acids makes them an FDA-approved mechanical seal, often adopted by the food and drink processing industry. As for their temperature resilience, the lowest they can take is about -40°F, and the highest: 158°F.


Defining Characteristics

·         Durometer Rating: 60

·         Better Than: Synthetic rubber

·         Best Resistance: Alcohol, ketones, dilute, and organic acids.

·         Merits: Waterproof and FDA-approved.

·         Standard: Must comply with US FDA 21 CFR177.2600 for rubber in repeated contact with food, and (EC) No 1935/2004 for rubber that may or may not come into contact with food.