Silicone rubber is a synthetic rubber made from silicon, unlike natural rubber. It's an essential compound with excellent performance in various fields, making it a widely applicable material and the reason for its use in nearly all industries' products. Silicone rubber exhibits remarkable resistance to extreme temperatures, whether in hot or cold conditions. Compared to traditional rubber, silicone rubber exhibits significantly superior tensile strength, elongation, tear resistance, and compression set performance under extreme temperatures.
It also has good aging resistance, excellent electrical insulation, low toxicity, biocompatibility, and great sealing performance. Because of its properties, it is widely used in many fields. In the medical field, it is used to make things like catheters and artificial organs. In the electrical and electronic field, it is used for insulating materials and cable sheaths. In the automotive industry, it is used to make seals and shock-absorbing parts. In the food and beverage industry, it is used to make food-grade seals and baking molds. In the aerospace field, it is used for engine and fuel system seals.
What is Silicone Rubber Made From?
Silicone rubber is a type of synthetic rubber mainly composed of siloxane polymers, which consist of silicon, oxygen, and organic groups. Its main chain is a siloxane chain formed by alternating silicon and oxygen atoms, endowing it with unique thermal stability and flexibility. The high strength of the silicon-oxygen bond gives silicone rubber high temperature resistance and excellent chemical stability.
The processing of silicone rubber typically involves these steps: First, prepare siloxane polymers, organic group reagents, fillers like silica, cross-linkers like peroxides, and additives like antioxidants. Next, thoroughly mix the siloxane polymers with fillers and additives in a mixer for even dispersion. Then, add the cross-linker and trigger the cross-linking reaction via conditions like heating or light exposure. For instance, heated peroxides decompose into free radicals, cross-linking siloxane chains into a 3D network, while platinum-catalyzed hydrosilation reactions enable precise cross-linking under mild conditions for high-performance products. After that, put the cross-linked silicone rubber into a mold and form it into the desired product shape through molding processes such as compression molding, extrusion, and injection molding. Finally, post-treat the molded items with heat treatment, surface treatment, etc., to enhance performance, remove impurities, and improve surface properties.
Properties of Silicone material
With Extreme Temperature Range
Usually working in the temperature range of -50°C to 200°C, and special ones can reach -100°C to 250°C.
Good Sealing Performance
Tensile Strength Range: 200-1500 P.S.I.
Elongation: 700% Maximum
Durometer (Hardness) – Range: 30-90 Shore A
Resistances
Abrasion Resistance: Fair to Poor
Tear Resistance: Poor
Solvent Resistance: Poor
Oil Resistance: Fair to Poor
Aging Weather - Sunlight: Excellent
General Characteristics
Adhesion to Metals: Good
Compression Set: Good
Resilience/Rebound: Good
Electrical Properties
Dielectric Strength: 400 - 600 volts/mil
Volume Resistivity: 10¹³ - 10¹⁶ ohm - cm
Arc Resistance: 120 - 180 seconds
Flammability
UL 94 Rating: Usually V-0 (self - self-extinguishing in most formulations)
Flame Spread Index: Low
Thermal Conductivity
Thermal Conductivity Value: 0.12 - 0.20 W/(m·K)
Water Absorption
Water Absorption Percentage: Less than 0.5% by weight after 24 hours of immersion
Permeability
Gas Permeability: Moderate to high for some gases, like oxygen and carbon dioxide
Moisture Vapor Transmission Rate (MVTR): Low to moderate, depending on formulation
Chemical Resistance
Acid Resistance: Fair to good against weak acids, poor against strong acids
Base Resistance: Fair to poor
Biocompatibility
Medical Grade Compatibility: Widely used in medical devices due to high biocompatibility
Toxicity Level: Low - generally non-toxic and non-irritant
Processing Characteristics
Ease of Molding: High, can be molded using various techniques like injection molding, compression molding, and extrusion
Curing Time: Varies depending on formulation and curing method, can range from seconds to hours
Benefits and Advantages of Silicone
Silicone offers numerous benefits and advantages in various applications, mainly due to its unique chemical and physical properties. The following are some of the key benefits and advantages:
Versatility: Silicone can be easily formulated and processed into various forms, including liquids, gels, elastomers, and resins, to meet different application requirements.
Wide Temperature Tolerance: It can maintain good performance in extreme temperatures, ranging from very low to high, generally from -50°C to 200°C. Some special silicone rubbers can even withstand temperatures as low as -100°C or as high as 250°C.
Excellent Chemical Resistance: Silicone is highly resistant to a wide array of chemicals, including oils, solvents, acids, and alkalis.
Superior Electrical Insulation: Due to its exceptional electrical insulation, high dielectric strength, and low electrical conductivity, silicone is extensively utilized in the electrical and electronics sectors.
High Flexibility and Elasticity: Silicone maintains its flexibility and elasticity over a large deformation range, even at low temperatures.
Good Weatherability: It is highly resistant to ultraviolet (UV) radiation, ozone, and moisture, which enables it to retain its properties when exposed to outdoor elements for extended periods.
Low Toxicity and Biocompatibility: Silicone is generally non-toxic and has excellent biocompatibility, making it safe for use in contact with the human body.
Excellent Flame Retardancy: With the addition of flame retardant additives, certain silicone products achieve UL94 V-0 certification, following the UL94 (USA) flammability standard
Fire Resistance: Some silicone-based materials have good fire-resistant properties, which can slow down the spread of fire and release fewer harmful fumes.
What are the common applications of silicone?
Silicone has a wide range of applications in various fields due to its excellent properties, such as high temperature resistance, chemical stability, and biocompatibility. The following are some of its common applications:
Medical Field: Catheters, tubing Medical seals Drug-delivery systems.
Electronics and Electrical Industry Insulating wires, cables Electronic components Semiconductor chip encapsulation
Automotive Industry Weather stripping and seals Engine gaskets and seals Electrical connector seals Vibration-damping engine mounts
Aerospace and Aviation Aircraft engine seals Fuel system components Cockpit window seals
Construction Industry Window glazing seals Window and door weatherstripping Expansion joint fillers
Food and Beverage Industry food-grade seals, gaskets
Your Trusted Partner for Custom Silicone Solutions
While silicone excels in many applications, it's unsuitable when exposed to oils, solvents, or abrasive conditions. Since alternative, cost-effective materials exist, selecting the optimal compound for your needs is crucial. ZYXrubber simplifies material selection by partnering with businesses to analyze needs and deliver custom-designed part solutions using the most cost-effective materials.
Our experts work with you to analyze your needs and provide custom-designed part solutions based on your goals. include custom silicone tubing, o-rings, gaskets, and other parts. Contact us or call 86-199-2560-3717 to request a quote today to get started with custom silicone rubber production with ZYXrubber.
