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Identifying silicone and rubber

What is Rubber?

Generally, we consider all elastic materials as rubber, whose dimensions change when subjected to large tensile stress and return to their original size when the stress is removed. Rubber is divided into two types: natural rubber and synthetic rubber. Natural rubber is extracted from plants such as rubber trees and rubber grass and processed into rubber after extracting the gum; synthetic rubber is obtained by polymerization of various monomers.


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What is Silicone?

Silicone, also known as silicone rubbers, is a polymer compound composed of silicon and oxygen. Due to the high energy of the silicon-oxygen bond, silicone is more heat-resistant than other rubbers or elastomers. In addition, the silicon-oxygen bond in silicone has resistance to ozone and UV attacks, allowing it to be used for long periods of time in a variety of harsh environments. Therefore, it has been widely used in industries such as electronics, construction, medical, and food processing.


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Silicone-related Terminology

Both of Silicone polymers and rubber are in the injection moulding raw material list.


Terms such as  silicone elastomerand silicone polymer all describe synthetic materials containing silicon. Their relationship can be explained as follows:


Silicone polymers are a class of large molecule compounds formed by covalent bonding of silicon atoms with other elements such as oxygen, carbon, and hydrogen. They can exist in various forms, such as oil, resin, gel, and elastomer. This compound has excellent thermal stability, chemical stability, and electrical insulating properties, making it widely used in industrial lubricants, medical implants, electronic protective coatings, and many other fields.


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Silicone elastomer is a special type of silicone polymer composed of elements such as silicon, oxygen, carbon, and hydrogen. It has good elasticity and can return to its original shape after being stretched or deformed. Silicone elastomers can maintain their elasticity in high or low temperature environments, and are therefore commonly used in the manufacture of seals, gaskets, kitchen utensils, medical equipment, and other products.


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To summarize, silicone polymers are a broad category that includes various forms of silicon-containing materials, including silica gel and silicone elastomers. Silica gel and silicone elastomers are both forms of silicone polymers, but they have different properties and uses.


Differences between silicone and rubber

Silicone is a form of synthetic rubber. Both rubber and silicone rubber are elastic materials that can deform under high tensile stress and recover their original shape when the stress is removed. Although they are similar in some respects, they also have many differences.


Heat resistance

Both natural rubber and silicone can operate at low temperatures. In fact, these materials can operate efficiently in environments as cold as -50°C. However, when natural rubber is used in continuous environments with temperatures above 85°C, it becomes stiff and loses elasticity. On the other hand, the silicon-oxygen bond structure in silicone gives it excellent heat resistance, allowing it to withstand elevated temperatures of up to 200-300°C. Therefore, in applications that require high temperature resistance, silicone is the better choice.


Chemical Properties

The key difference between rubber and silicone rubber is that the main chain of silicone rubber contains silicon and oxygen, while the main chains of most forms of rubber contain carbon-carbon bonds. The skeleton of silicone consists of silicon and oxygen, while the skeleton of rubber contains carbon-carbon bonds, resulting in significant differences in chemical properties. Therefore, silicone is more resistant to chemical corrosion and oxidation than rubber.


Electrical Properties

Silicone has excellent electrical insulation properties, making it a good choice for insulators in electrical and electronic devices. This electrical insulation property of silicone is due to the large number of silicon-oxygen bonds in its molecular chain, which gives it good electrical insulation and arc resistance. In comparison, although natural rubber also has good insulation properties, its double bonds in the molecular chain are prone to oxidation reaction, making it rapidly age in high temperature, humid and other environments. Therefore, in some high-demand electrical and electronic devices, silicone is a better choice.


Environmental Impact

Although natural rubber is a renewable resource, rubber tree planting requires land occupation and consumes a large amount of water resources. At the same time, the production of natural rubber also generates wastewater and waste, which need to be treated and cleaned, causing environmental impact. In contrast, silica gel is a synthetic material made from silicon (sand). Although the extraction and processing of silicon also have an impact on the environment, these impacts can be minimized by adopting more environmentally friendly production methods and technologies. In addition, one of the advantages of silica gel is that it is not biodegradable, which means that it can be used for a long time without polluting the environment.


Tensile Strength

Generally, natural rubber has better tensile strength than silicone, allowing it to withstand higher levels of stress and strain and bounce back to its original shape. This is one of the reasons why it is commonly used in items such as rubber bands, tires, and certain types of gaskets and seals. While silicone may not be as strong in terms of tensile strength, its strength can be adjusted for different applications by altering the formula and manufacturing process of the silicone.


In summary, although silicone and rubber both belong to elastomers, the differences between them are very obvious. The specific choice between silicone and rubber will depend on the requirements of the application, such as the expected temperature range, exposure to chemicals or UV light, electrical needs, budget, and environmental considerations.


Rubber

Silicone

-50°C-85°C

-50°C-300°C

carbon-carbon bonds

silicon-oxygen bond

good insulating properties, but not as good as silicone.

good electrical insulation and arc resistance

Renewable resources

Non-biodegrad

 can undergo intense stretching stress and return to their original dimensions after the stress is removed

adjust the tensile strength of silicone by changing its formula and manufacturing process

 

Types of silicone & rubber

Rubber is a widely used material with many different types, natural rubber and synthetic rubber are two common types. In addition, there are other types of rubber such as nitrile rubber, chloroprene rubber, and butyl rubber. These different types of rubber have different characteristics and can be used for various applications.


Natural Rubber: This type is harvested mainly in the form of latex from the Para rubber tree. The latex is a sticky, milky colloid drawn off by making incisions in the bark and collecting the fluid in vessels. This process is called "tapping." The latex then is refined into rubber ready for commercial processing.


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Synthetic Rubber: Synthetic rubber refers to artificial rubber manufactured through chemical processes. It has been widely used as a substitute for natural rubber, and can be produced using raw materials such as petroleum or natural gas. Includes many different types, such as:


  • Styrene-Butadiene Rubber (SBR): Used in tires because of its abrasion resistance.


  • Nitrile Rubber (NBR): Has excellent oil resistance, so it's often used in oil seals and O-rings.


  • Neoprene (CR): Resistant to weathering, ozone, and heat, and also has good flame retardancy. It's used in a variety of applications, including electrical insulation and gaskets.


  • Ethylene Propylene Diene Monomer (EPDM): It is resistant to weathering, ozone, and many chemicals and is often used in outdoor applications, like roofing materials.


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Styrene-Butadiene Rubber

Silicone is a versatile material and comes in a variety of forms, each with its unique properties and applications. Here are some common types:


Liquid Silicone Rubber (LSR): This is often used in applications that require complex, high-precision parts, like medical devices and kitchen utensils.


High Consistency Rubber (HCR): This type of silicone is often used in applications that require high heat resistance, like gaskets and seals in high-temperature environments.


Room-Temperature-Vulcanizing (RTV) Silicone: This is a type of silicone rubber that cures at room temperature, and it's often used in mold-making and in adhesives and sealants.


Fluorosilicone Rubber (FSR): This has improved chemical resistance compared to other types of silicone and is often used in applications that involve exposure to fuels and other harsh chemicals.


Applications of silicone and rubber

Silicone and rubber are versatile materials with a wide range of applications due to their distinct properties. Here are some applications for both:


Automobile Manufacturing

In the automotive manufacturing industry, rubber and silicone are essential materials for plastic injection molding automotive parts. Rubber is widely used to manufacture tires, seals, and pipes, while silicone is used to manufacture sealing gaskets, tire coatings, and electronic components. For automobile manufacturers, choosing high-quality rubbers and silicones are crucial because the quality of these materials directly affects the safety, reliability, and performance of automobiles.


Construction Industry

In the construction industry, rubber is widely used to produce waterproof and seismic materials due to its durability and elasticity, such as rubber flooring, rubber roofing, and rubber door mats. Silicone is also highly favored for its high temperature resistance, sealing and plasticity. It can be used to manufacture sealants and building sealant materials, such as silicone flooring, silicone glass, and other products that effectively prevent water and air penetration, maintaining a comfortable and dry indoor environment.


Medical equipment

Rubber and silicone are very common materials used in medical injection moulding. Rubber is made from natural or synthetic substances and is typically used to manufacture sealing components and pipelines in various medical devices. In contrast, silicone is a chemically synthesized material that has characteristics such as adsorption, permeability, and high temperature resistance. Therefore, silicone is mainly used to manufacture contact surfaces and coatings in medical equipment, such as artificial lenses, pacemakers, and oximeters.


Advantages of silicone and rubber products

Both silicone and rubber products have their unique advantages, making them suitable for various production process. Here's a brief overview of each:


Rubber Products:


  • High Elasticity: Rubber products have high elasticity, can withstand significant stretching force, and have good shape memory, making them very suitable for applications that require high flexibility and durability.


  • Wear Resistance: Rubber has excellent wear resistance and impact resistance, and can withstand a lot of friction and impact, making it an ideal choice for products such as tires, belts, and seals.


  • Cost-benefit discount:Natural rubber is usually cheaper than silicone, making it a more cost-effective choice in product manufacturing.


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Silicone Products:


  • Heat Resistance:One of the most significant advantages of silicone is its excellent temperature resistance, as it can maintain its physical properties and performance at high temperatures, making it an ideal choice for products such as engine components, cookware, and electronic devices.


  • Corrosion Resistance: Silicone has resistance to many chemicals, including water, ozone, and ultraviolet rays. This makes it ideal for outdoor applications and environments where it may come into contact with different chemical substances.


  • Excellent Electrical Insulation:Silicone is an excellent electrical insulation material with outstanding electrical properties. It is widely used in the manufacturing of electronics


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How to choose a silicone supplier?

China is one of the world's largest producers of silicone, providing a wide range of high quality and affordable products with excellent communication and collaboration skills to meet customer needs and requirements. Therefore, when choosing a silicone supplier, the following factors should be considered:


First, we need to ensure that the supplier has sufficient experience and professional knowledge to provide high-quality silicone products. Secondly, we need to ensure that the supplier's production equipment and processes comply with industry standards and have sufficient capacity to meet our needs. In addition, we also need to consider whether the supplier's prices and delivery times are reasonable. Finally, we should understand the supplier's after-sales service timeliness and quality, so that we can receive timely support and solutions when problems arise.


Keyplast is a high-tech enterprise established in 1978 that uses high-quality silicone rubber for product manufacturing. With a professional team and rich manufacturing experience, it can provide tailor-made solutions for multiple markets.


Top 5 Silicone Suppliers

1.Shenzhen Hong Ye Jie Technology Co., Ltd.

2.Shenzhen Rongxingda Polymer Material Co., Ltd.

3.Foshan Chngoo Co., Ltd.

4.Xiamen Hands Chain Silicone Co., Ltd.

5.Key-Plast Co., Ltd.

 

Conclusion Of silicone and rubber

In general, rubber and silicone are common injection molding materials, but due to their different properties, they are suitable for different applications. Rubber has good elasticity and wear resistance, but is prone to aging and deformation at high temperatures. It is usually applied in industries such as automobile manufacturing, construction, and medical. Silicone is more resistant to high temperatures and corrosion than rubber, and can maintain elasticity even at low temperatures. It has also been widely used in fields such as electronics, medical, and aerospace. Therefore, the choice between rubber and silicone mainly depends on the specific requirements of the application.


Keyplast Injection Molding

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