Whilst a gasket may be a relatively simple component in many cases, the importance of choosing the right gasket materials cannot be underestimated. Selecting a material that lacks the required properties leads to gasket failure, the repercussions of which can be extremely costly, both in terms of production delays and equipment damage, or even injury.
Gaskets come in many different variations, shapes and sizes, including flat gaskets and moulded gaskets. Regardless of the shape of a gasket, its most important function is to provide a buffer between two mating surfaces, acting as a mechanical seal against liquids, gas, dust or any other element that could be detrimental to the application.
These functions considered, in order for a gasket to be successful, it’s vital that it is manufactured from a material that can resist the elements it will be exposed to in order to maintain an efficient seal.
Let’s address some of the key factors to be considered when choosing the right gasket materials.
Selecting Resistant Gasket Materials
There are a range of environmental factors that can impact on the efficiency and durability of a gasket. Depending on the application, you may need to consider:
UV/Ozone
Outdoor applications are subjected to UV light from the sun and Ozone from the atmosphere, which can result in gasket degradation for materials that do not exhibit strong UV resistance. Materials such as Nitrile rubber and natural rubber are ill-suited for outdoor applications as they can be attacked by UV and Ozone, whereas Silicone rubber is a good choice for outdoor gaskets as it performs well when exposed to UV and Ozone.
Chemicals
Resistance to chemicals, oils and fuels may be an important factor to consider when choosing materials for certain gasket applications. When certain materials are exposed to abrasive chemicals, they can deteriorate, causing a gasket to fail. EPDM rubber offers a good resistance to many chemicals and hydraulic oils, making it an ideal gasket choice for automotive applications.
Moisture
Gaskets for preventing sealing against liquids must be non-absorbent and moisture resistant. Neoprene and Silicone rubbers react well when exposed to water or moisture for long periods of time.
Shock and Vibration
In applications where vibration or shock can cause damage to components, a shock absorbing gasket material is important to dampen any shock that could lead to product or equipment failure. Developed for use in the Rail industry, HT800 Silicone Sponge features a compact cell structure that resists impact and isolates vibration, making it an ideal choice for protective gaskets.
Temperature
Another factor that cannot be ignored when selecting gaskets is temperature resistance. In certain applications, sealing material must be able to withstand extreme low and/or high temperatures, as well as temperature fluctuations, without changing shape or degrading. Silicone rubber materials generally provide a strong resistance to extreme temperatures.
Compression
The compression set of a material is how much a certain material can be compressed without its shape being permanently deformed. A material with a high compression set will not return to its original shape after compression, whereas a material with a low compression set is highly flexible and will return to its original shape and density after compression.
Low compression set materials, for example, Silicone foams or PORON® Urethane, are well suited for electrical and lighting enclosure gaskets, preventing the ingress of dust and debris. For strong gasket materials with a high compression set, EPDM rubber can provide a good solution.
Shore Hardness
In order to find a suitable gasket material, the materials’ shore hardness must be considered. A sealing material must be soft enough to fit a gap between two mating surfaces, but also hard enough to withstand pressure, vibration or impact it is exposed to. Soft materials such as cellular sponges and foams have a low shore hardness, whereas hard plastics and rubber compounds feature a high shore hardness. Solid rubber materials feature a more balanced shore hardness.
When it comes to finding a gasket material with a suitable shore hardness, it is always advisable to work with experienced gasket manufacturers to identify the materials that best suit your application.
Industry Standards
In addition to providing necessary strength, durability and resistance, gaskets are also subject to many industry standards for safety. For example, sealing materials for use in the rail industry must meet standards including EN45545-2, BS6853:1999, NFF-16-101 and the LUL (London Underground) safety standards. In order to choose materials that comply with necessary industry standards, it is important to seek technical advice from gasket manufacturers.
Choosing Gasket Manufacturers
With over 100 years of experience in the rubber and plastics industry, CB Frost has gained considerable expertise in supplying and converting gasket materials for most industrial sectors, including rail, construction, lighting, HVAC, electrical, defence, and most recently, the electrical vehicles market.
As a UK industry leader, our team possesses excellent technical knowledge to advise customers on the most suitable gasket materials in our extensive rubber, sponge, foam product range. We also have extensive in house conversion capabilities, including high speed cutting, extrusion, moulding and fabrication.
To discuss your gasket needs, please contact us by calling +44 (0)121 773 8494.
