A Complete Guide to General Purpose Silicone Rubber
What is General Purpose Silicone Rubber?
General purpose silicone rubber is a widely used elastomer known for its combination of thermal stability, flexibility and resistance to various environmental factors. It is suitable for food contact applications with heat stability within a wide temperature range, typically from -50°C to 180°C. As an FDA-compliant material, it ensures safety and reliability in applications involving direct contact with consumables. Its balanced performance across a range of conditions makes it ideal for numerous everyday uses without focusing on a specific niche.
Composed of silicon-oxygen polymer chains, general purpose silicone rubber exhibits the inherent properties of silicone, such as resistance to extreme temperatures, UV light and ozone. Unlike specialised grades such as high-temperature or steam-resistant silicones, it is considered a suitable material for everyday applications that require rubber sealing solutions that offer durability, flexibility and cost-effectiveness.
Appearance
Initially translucent but can be pigmented to any RAL colour.
Tear Strength
Resistance
to tearing around 26N/mm.
Density
Formulated
for a density of between 1.5 g/cm3 and 1.2g/cm3.
Hardness
Available
between 24ᵒ Shore A and 79ᵒ Shore A.
Tensile Strength
Tensile
strength between 9N/mm2 and 10N/mm2.
Elongation at Break
Flexibility
between 420% and 920% without breaking.
Temperature Range
Operates
effectively between -50°C and 180°C.
Rebound Resilience
Recovery
from deformation between 42% and 53%.
Learn how general purpose silicone is formulated, how it differs from specialist grades and common applications within the industry.
How is General Purpose Silicone Rubber Made?
The manufacturing process of general purpose silicone rubber begins with the synthesis of the base polymer. Silicon, extracted from silica sand, undergoes chemical reactions with hydrocarbons to produce chlorosilanes. These intermediates are then hydrolysed and polymerised to create polydimethylsiloxane (PDMS), the foundation of silicone rubber.
Reinforcing fillers such as silica are incorporated into the PDMS to enhance the mechanical strength and stability of the material. The formulation may also include additives to improve specific properties like colour, elasticity or processability. General purpose silicones typically use curing agents such as peroxides or platinum catalysts to initiate the vulcanization process, where cross-linking between polymer chains occurs. This step transforms the raw material into a solid rubber with the desired elasticity and resilience.
Compared to specialised silicone rubbers, the production of general purpose silicone involves fewer advanced additives or curing methods. This results in the production of a cost-effective material that is suitable for a wide range of standard applications. After curing, the rubber undergoes quality control testing to ensure consistency and performance. It can then be extruded into rubber sections for sealing applications.

Advantages of General Purpose Silicone Rubber
General purpose silicone offers a balanced set of properties that make it suitable for diverse applications. One of its most notable features is its thermal stability which allows it to operate effectively across a temperature range of approximately -50°C to 180°C. This makes it a reliable choice for environments with moderate temperature variations.
The material also exhibits an excellent resistance to environmental factors such as UV radiation, ozone and weathering. These properties make it suitable for outdoor applications and products exposed to prolonged sunlight or harsh weather conditions. Additionally, general purpose silicone rubber is chemically inert and resistant to many common oils, solvents and chemicals. This helps ensure durability in contact with various substances and suitability for use in the medical industry.
Flexibility and elasticity are key characteristics of general purpose silicone. This helps it maintain its shape and performance under mechanical stress. It is also non-toxic and can be formulated to meet a food-grade or medical-grade standard which expands its range of applications. Furthermore, the materials affordability compared to specialised silicone rubber or other compounds makes it a practical choice for general-purpose use.

Common Applications and Uses
Silicone rubbers versatility makes it an essential material across many industries. Its balanced properties enable it to address diverse needs in healthcare, food processing and construction.
Industries

Food and Beverage
For the food industry, general purpose silicone rubber is widely employed in food preparation and storage products. It is used in seals, gaskets, and moulds for food processing equipment and kitchenware. Its heat resistance and non-toxic properties allow it to endure high-temperature cooking or baking without compromising food safety. Being FDA-compliant ensures that it meets stringent safety regulations, making it a reliable choice for food-grade applications.

Medical, Pharmaceutical & Healthcare
In the healthcare sector, general purpose silicone rubber is often used in non-critical medical components such as tubing, rubber seals and stoppers. Its biocompatibility and ability to meet FDA standards make it a safe choice for contact with bodily fluids. The materials resistance to sterilisation processes, including autoclaving, ensures it remains functional and durable in medical environments. Additionally, its flexibility and inert nature make it ideal for disposable and reusable medical devices.

Construction
In the construction sector, general purpose silicone rubber is one of the preferred materials for sealants, adhesives and gaskets used in windows, doors and building joints. It offers excellent weatherproofing capabilities which help maintain its flexibility and strength even when exposed to temperature fluctuations, UV light and moisture. This durability ensures long-lasting seals that contribute to energy efficiency and structural integrity, making it a valuable material for both residential and commercial construction projects.
Material Compound Datasheets
General purpose silicone can be extruded in a range of different hardnesses, each suitable for different applications. The properties and characteristics of these hardnesses may differ. Please see the downloadable PDF material compound datasheets for this information.
Looking for a different grade of Silicone?
As well as general purpose Silicone, we are also able to manufacture rubber sealing products in a selection of other specialised Silicone compounds. This includes high tear strength silicone, metal detectable silicone, high temperature silicone and flame retardant silicone.
Contact Us
With over 50 years' experience in the rubber sealing industry, our team has extensive experience in finding sealing solutions for our customers. Contact our experts via phone or email for sealing advice or bespoke quotations.
Email:
sales@sealsplusdirect.co.uk
Telephone:
01425 617722