Most of the synthetic rubber used today is used to create a range of rubber moulded products.
Compared to other materials like steel or plastic, rubber is a complex material with various components undergoing a chemical reaction during vulcanisation before entering the manufacturing cycle.
Rubber moulding challenges
Rubber can take on many shapes in its applications and maintain its properties through a lifetime of dynamic stressing. As a result, the rubber used for moulding must be tough enough to fulfil its function even after being stretched or twisted thousands of times.
Another challenge rubber needs to withstand in moulding applications is extreme temperatures.
By understanding all the requirements for a rubber compound, a rubber formulation chemist will determine the different components to create the ideal compound. However, the exact formulation for optimal performance is difficult to determine. Therefore, the following factors are tested before the actual product is developed:
- Fluid immersion
- Ozone ageing
- Temperature stressing
- Elongation testing
- Tensile strength
Pneumatic Rubber seals
Pneumatic Rubber seals can be manufactured in many different shapes and sizes.When selecting the rubber compound for moulding pneumatic rubber seals, the engineer needs to know what conditions the pneumatic rubber seal will be exposed to to ensure it can withstand those challenges.
Rubber compound considerations
Each rubber compound has different physical characteristics like durometer hardness and tensile strength. Durometer hardness is the hardness of a material and a lower durometer results in more impression. These rubber products are generally less dense and more supple.
Tensile strength is the maximum stress the pneumatic rubber seal can undergo while being stretched or pulled – whether it is brittle or more tear and crack resistant.
These are the most common materials rubber seals are made from:
This is an all-purpose polymer, and neoprene rubber seals are moderately resistant to petroleum products while offering good resistance to the ozone and weathering. Homogenous neoprene rubber seals provide moderate resistance to oil. Sponge neoprene rubber seals contain tiny individual sealed cells to resist moisture, dirt, and air.
Ethylene Propylene Diene Monomer (EPDM)
EPDM provides excellent resistance to weathering, ozone, and UV rays. In addition, it is an affordable synthetic rubber that is exceptionally durable and flexible. As a result, it is ideal for manufacturing a range of different types of rubber seals.
This is one of the most widely used materials. Nitrile rubber seals are highly resistant to oil and chemicals. It can also withstand temperatures from -40°C to 108°C. As a result, it is ideal for manufacturing rubber seals used in various applications.
Silicone is non-reactive, stable, and resistant to extreme temperatures, ozone exposure, UV and general weathering. It can be used from -60°C to 232°C without becoming brittle in freezing conditions or losing dimensional tolerance at extremely high temperatures. Silicone is used frequently in the production of O-rings, seals, and gaskets.
Butyl is a synthetic rubber used to manufacture elastic rubber seals that are resistant to cracking and degrading. It offers exceptional air-barrier performance and is excellent for vibration damping.
Fluorosilicone is a long-lasting rubber product that is stable in extreme temperatures. Its unique properties ensure it’s widely used in various industrial applications for sealing products.
Polytetrafluoroethylene (PTFE) is a synthetic compound that is non-reactive, making it ideal for corrosive chemical applications. In addition, it is self-lubricating and resistant to acids most chemicals.
Commonly referred to as Viton®, this is a rubber compound that can withstand high temperatures, is resistant to oil and resistant to a wide range of chemicals, and surpasses the fluid resistance of other commercial rubbers. As a result, it is ideal for applications that require hard-wearing O-rings, gaskets, and pneumatic rubber seals.
The more aggressive and unforgiving the environment, the more critical it becomes to optimise the seal design and material selection. With exceptional Chemical and Thermal resistance, our FFKM O Rings combine Sealing Performance of Elastomers with chemical resistance comparable with PTFE.
Contact Fuzion Trading for details
Moulded rubber seals are created through custom-fit moulds and are usually done for pneumatic applications and specialist engineered applications. We supply rubber seals for various applications from the highest-grade materials. If you want to learn moreor are interested in any of our offers, get in touch with one of our representatives.