What Are the Different Types of Silicone Rubber?
Silicone rubber is a versatile material known for its unique properties and wide range of applications. There are several types of silicone rubber, each engineered for specific uses and performance characteristics and featuring different physical properties, chemical compositions, and curing methods.
In this guide, we will provide an overview of the different types of silicone rubber, the properties of silicone rubber, and the disadvantages and advantages of silicone rubber.
Order different types of silicone rubber with us today. Expert silicone manufacturer based in the UK.What is Silicone Rubber?
Silicone rubbers are flexible materials made from silicone polymers. They are strengthened with additives such as carbon, hydrogen, or oxygen, along with a crosslinker and catalyst. The crosslinker bonds polymer chains together during manufacturing.
As elastomers, silicone rubbers stretch or compress under pressure and bounce back to their original shape when the pressure is released. They come in different types like:
- Heat Cured Rubber (HCR)
- Liquid Silicone Rubber (LSR), and Room Temperature Vulcanization (RTV-1 and RTV-2), each processed at specific temperatures to achieve varying viscosity and structure.
These rubbers are enhanced with additives like mineral fillers or silicone resins to improve properties such as flexibility, tear strength, and temperature resistance.
They can also be customised with additional additives, like colourants or agents for fire resistance and easy release from moulds. This versatility allows silicone rubbers to perform well in diverse applications, meeting specific needs across industries.
United Silicones provides a wide range of custom silicone tubing specifications for your application. Talk to us today.
Properties of Silicone Rubber
Silicone rubber is a highly versatile material known for its unique combination of properties. Here are some of the key properties of silicone rubber that make it widely used in various industries.
The Advantages of Silicone Rubber
Temperature Resistance: It maintains elasticity and mechanical properties over a wide temperature range, typically from -50°C to 250°C, depending on the formulation.
Flexibility and Elasticity: Silicone rubber is highly flexible and elastic, allowing easy moulding and stretching without losing its shape or properties.
Chemical Resistance: It resists water, oxidation, ozone, and many chemicals, enhancing durability in various environments.
Electrical Insulation: With excellent electrical insulation properties, it is ideal for critical applications in electrical and electronic equipment.
Biocompatibility: Medical-grade silicone rubber is biocompatible and safe for medical implants and devices used in contact with the human body.
Non-stick Surface: Silicone rubber is naturally non-stick, beneficial for applications such as baking moulds and cooking utensils.
UV and Weather Resistance: It withstands UV radiation and weathering, making it suitable for outdoor applications.
Tear Resistance: Silicone rubber has good tear strength, contributing to its durability in mechanical applications.
The Disadvantages of Silicone Rubber
Poor Tear Strength: Silicone rubber has relatively low tear strength compared to other elastomers. This means it can tear more easily under stress.
High Cost: Silicone rubber is generally more expensive than other types of rubber due to its complex manufacturing process, meaning it may not be cost-effective for all applications, especially where large quantities are needed.
Limited Oil and Solvent Resistance: Standard silicone rubber does not perform well in environments with prolonged exposure to oils and solvents. Meaning it is not suitable for applications involving frequent contact with oils, fuels, or solvents.
Abrasion Resistance: Silicone rubber has poor abrasion resistance, meaning it can wear down quickly when subjected to friction.
Adhesion Issues: Silicone rubber has low surface energy, making it difficult to bond with other materials without special adhesives or surface treatments.
Appearance: Silicone rubber may not always be aesthetically pleasing, as it can appear less refined compared to other materials.
If you would like to know more about the uses of silicone in different industries, take a look at our What is Silicone Tubing Used For? guide.
The Different Types of Silicone Rubber and Their Applications
From kitchen appliances and automotive applications to medical devices, different types of silicone rubber have been utilised for their unique properties and applications.
High Consistency Rubber (HCR)
High Consistency Rubber (HCR) is known for its thermal stability, chemical resistance, mechanical strength, and biocompatibility.
Advantages:- It can withstand temperatures from approximately -50°C to 300°C, making it suitable for both high and low-temperature applications.
- Has a chemical resistance to many oils, acids, alkalis and solvents, making it suitable for many chemical, mechanical and industrial applications.
- High-strength material, providing durability and reliability in demanding environments.
- Higher cost due to stringent manufacturing and testing requirements.
- Requires expertise in handling and processing to maintain biocompatibility.
Industrial applications:
- HCR is commonly used in seals, gaskets, and flexible components across automotive, aerospace, medical, and industrial sectors.
Liquid Silicone Rubber (LSR)
- Liquid Silicone Rubber (LSR) is characterised by its liquid form before curing, allowing for precise injection moulding of complex shapes.
- LSR exhibits excellent thermal stability, flexibility, durability, and biocompatibility.
- It can withstand temperatures from approximately -55°C to +300°C, making it ideal for automotive, medical, and consumer product applications.
- LSR is resistant to UV light, weathering, ageing, and various chemicals, making it suitable for demanding environments.
- LSR's liquid form allows for precise injection moulding of complex shapes, making it ideal for intricate industrial components.
- However, its higher cost compared to other types of silicone may limit its use in some industrial applications where cost-effectiveness is a primary concern.
- Additionally, LSR requires specialised equipment and expertise for processing, which may add to initial setup costs and production complexity.
Despite these considerations, LSR's exceptional properties make it a preferred choice in industries requiring high-performance materials with precise moulding capabilities.
Industrial applications:
- LSR is commonly used for automotive parts, medical devices, and advanced consumer electronics.
Fluorosilicone Rubber (FSR)
Fluorosilicone Rubber (FSR) combines the properties of silicone rubber with enhanced chemical resistance to fuels, oils, solvents, and other harsh chemicals. FSR maintains flexibility, elasticity, and thermal stability over a wide temperature range (-50°C to 300°C), making it suitable for aerospace, automotive, and industrial applications.
Advantages:- FSR shows enhanced chemical resistance to fuels, oils, solvents, and harsh chemicals.
- Can withstand temperatures from approximately -50°C to 300°C, displaying exceptional thermal resistance.
- Suitable for seals, gaskets, and components requiring resilience and durability in challenging conditions.
- Higher cost compared to standard silicone rubbers.
- May have slightly lower physical properties compared to standard silicones.
Industrial applications:
- FSR is commonly used in aerospace components, automotive seals, and industrial machinery where chemical resistance and durability are critical. - Links to relevant industries pages
High Temperature Vulcanised (HTV) Silicone Rubber
High-Temperature Vulcanised (HTV) Silicone Rubber is a robust material known for its excellent mechanical properties and high-temperature resistance. HTV silicone can withstand continuous temperatures from -50°C to +250°C, with special formulations capable of higher temperatures.
Advantages:- Excellent mechanical properties: Known for its mechanical strength and resilience.
- High-temperature resistance: Can withstand continuous temperatures from -50°C to +250°C.
- Suitable for moulding complex shapes and parts requiring superior mechanical strength.
- Thermal stability and reliability: Ideal for applications where durability is critical.
- Less flexible compared to liquid silicone rubber (LSR).
- Processing may involve longer curing times and higher temperatures.
Industrial applications:
- Widely used in automotive, aerospace, and industrial sectors for components requiring high-temperature resistance and mechanical strength.
Electrically Conductive Silicone Rubber
Electrically Conductive Silicone Rubber incorporates conductive fillers such as carbon or metal particles into silicone rubber matrices. This formulation provides electrical conductivity while maintaining the inherent properties of silicone rubber such as flexibility, elasticity, and temperature resistance.
Advantages:- Electrical conductivity: Provides EMI shielding and static dissipation.
- Retains silicone rubber properties: Maintains flexibility, elasticity, and temperature resistance.
- Suitable for electrical connectors, flexible circuits, and components in electronic devices, automotive, and aerospace systems.
- Higher cost due to specialised formulations and conductive fillers.
- Conductive fillers may affect other properties of the silicone.
Industrial applications:
- Used in applications requiring EMI shielding, static dissipation, and electrical conductivity in various electronic and automotive components.
Medical Grade Silicone Rubber
Medical-grade silicone rubber is specially formulated to meet stringent biocompatibility and safety standards for medical and healthcare applications. It is non-toxic, hypoallergenic, and biocompatible, making it suitable for use in medical implants, devices, seals, gaskets, and tubing.
Advantages:- Biocompatibility: Meets stringent biocompatibility and safety standards.
- Non-toxic and hypoallergenic: Suitable for medical implants and devices.
- Maintains properties under sterilisation: Resistant to autoclaving, gamma irradiation, and ethylene oxide sterilisation.
- Longevity and reliability: Critical for medical applications.
- Higher cost due to stringent manufacturing and testing requirements.
- Requires specialised handling and processing to maintain biocompatibility.
Industrial applications:
- Essential in medical and healthcare sectors for applications requiring reliability, longevity, and patient safety in various medical devices and implants.
Why Choose United Silicones?
When selecting a silicone rubber manufacturer, reliability and expertise are essential. We pride ourselves in being leaders in this industry due to our commitment to quality and innovation.
Our extensive experience ensures that clients receive the best materials tailored to their specific needs and we ensure that we continually source high-quality materials and resources to ensure that we deliver exceptional products. Our team of experts is dedicated to helping you choose the right type of silicone rubber for your application, ensuring optimal performance and durability.
