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What You Should Know About Silicone Rubber
July 27,2021
People often mistake silicone as a kind of plastic due to its malleability, water resistance, and flexibility. The plastics industry also considers silicone as plastic. We would say: No, Silicone isn’t plastic, even though it does share some characteristics with common plastic that we’re all used to. Plastic comes with a ton of issues, such as leaching toxic chemicals into your food and drink, which silicone fixes. However, that’s why silicone becomes so popular. Technically, silicone could be considered part of the rubber family.
（Extension Reading: Is Silicone Rubber better than Rubber?）
What Is Silicone rubber?
Silicone rubber is also known as elastomer (rubber-like material) composed of Silicon (a naturally occurring element), Oxygen, Carbon, Hydrogen. Silicone rubbers are widely used in industry, and there are multiple formulations. Silicone rubbers are often one- or two-part polymers. Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and temperatures from −55 to 300 °C (−70 to 570 °F) while still maintaining its useful properties. Due to these properties and its ease of manufacturing and shaping, silicone rubber can be found in a wide variety of products, including voltage line insulators; automotive applications; cooking, baking, and food storage products; apparel such as undergarments, sportswear, and footwear; electronics; medical devices and implants; and in-home repair and hardware, in products such as silicone sealants.
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What are the advantages of silicone rubber?
Advantage 1: High-Temperature Resistance
The most well-known property of silicone is high-temperature resistance, which can still work normally within the range of −55 to 300 °C (−70 to 570 °F). Heat resistance can reach 260°C, so silicone rubber is very suitable for cooking and mechanical equipment under severe environmental temperatures.
〈Extension Reading: High-Temperature Silicone: Characteristics, Applications, and Buying Guide〉
Advantage 2: Non-Toxic
Although silicone rubber is a polymer, it is composed of a fairly natural mineral (silica). This also creates the safety characteristics of non-toxic and heavy metal-free silicone rubber itself, so it is suitable for skin-friendly medical products and food-contact kitchenware containers.
Advantage 3: Waterproof
If there is something in common between silicone rubber and plastic, it is probably waterproof. However, the waterproof performance of silicone rubber is better than that of plastic. The reason is that the ductility and elasticity of silicone are very high after molding, unlike plastic parts that are shaped after molding. Therefore, it can often be seen that silicone rubber is used as a raw material for gaskets such as waterproof sealings and O-rings.
Advantage 4: Durable, Long Lifespan
From the perspective of silicone manufacturers, this is really not an advantage. Why? Because silicone rubber-made products have high tensile strength and are not easily deformed, the failure rate and replacement rate of the products are relatively low. Not only that, the wasted silicone rubber can be decomposed naturally in nature, and it can be said to be a very environmentally friendly material.
〈Extension Reading: Cultivating a Deeper Understanding of Silicone Hardness〉
| Physical Property | Data |
|---|---|
| Shore A(Hardness) | 25°–80° |
| Tensile Strength | 4-12.5 Mpa |
| Tear Strength | 9 - 55 kN/m |
| Elongation after fracture in % | 90 - 1120 % |
| Density | 1.1 - 1.6 g/cm3 |
| Insulation resistance | 1 - 100 TΩ.m |
What Are the Types of Silicone Rubber?
Liquid Silicone Rubber（LSR）
Liquid Silicone Rubber (LSR) is a low-viscosity silicone material known for its excellent flow and thermal curing properties, enabling rapid molding. LSR is soft, non-toxic, and resistant to high temperatures, making it ideal for medical devices, baby pacifiers, phone cases, and electronic seals. Additionally, it is suitable for large-scale automated production.
〈Extension Reading: Discover the Versatility and Benefits of Liquid Silicone Rubber (LSR)〉
Solid Silicone Rubber
Solid silicone rubber is a high-molecular polymer that forms after high-temperature vulcanization, offering greater strength and stability. It is suitable for manufacturing components requiring pressure resistance and tear strength, such as sealing rings, gaskets, and mechanical parts. Due to its durability, anti-aging properties, and precision processing capabilities, it is widely used in industrial and automotive manufacturing.
Silicone Foam Rubber
Silicone foam rubber is produced using a foaming process, incorporating uniform air pockets for excellent elasticity and cushioning. Lightweight and soft, it provides shock absorption, soundproofing, and resistance to extreme temperatures, making it a popular choice for vibration pads, waterproof sealing strips, and industrial packaging in electronics.
Applications of Silicone Rubber
Silicone rubber is applied in almost all industries. The following are some of its main application fields:
Medical and Healthcare
Due to its non-toxic and antibacterial properties, silicone rubber is extensively used in medical devices and health products, such as catheters, artificial skin, contact lenses, and surgical seals. Soft and hypoallergenic, silicone rubber is also applied to baby pacifiers, medical silicone pads, and prosthetics, providing users with a comfortable and safe experience.
〈Extension Reading: Applications of Liquid Silicone Rubber in Medical Devices〉
Electronics and Electrical Equipment
With its superior heat resistance, insulation, and waterproof properties, silicone rubber is ideal for producing wire sheaths, electronic component seals, and thermal conductive pads. These applications effectively protect devices from external damage and enhance heat dissipation. Thus, high-tech products like smartphones, computers, and household appliances heavily rely on silicone rubber.
〈Extension Reading: Behind the Scenes: Backlit Silicone Keypad Technology〉
Food and Cooking
Silicone rubber’s heat resistance, non-toxic nature, and lack of chemical reactivity with food make it suitable for the food and cooking industry. Common products include silicone baking trays, spatulas, airtight container seals, and baby tableware. Its softness and ease of cleaning enhance kitchen convenience while offering consumers safe and healthy choices.
〈Extension Reading: How to distinguish food-grade silicone and regular silicone?〉
Industrial and Construction
In the industrial and construction sectors, silicone rubber is primarily used as a sealant and adhesive. Its weather resistance, corrosion resistance, and high elasticity make it suitable for waterproof window seals, vibration-dampening automotive parts, and protective electronic coatings. Silicone rubber’s exceptional physical stability allows it to maintain long-term performance even in harsh environments, making it ideal for various infrastructure projects.
〈Extension Reading: The Future of Liquid Silicone in Automotive Applications〉
Consumer Goods
Silicone rubber’s waterproof properties, vibrant color options, and eco-friendliness make it widely used in consumer products like watch straps, phone cases, and fitness bands. Its plasticity and design flexibility also make it an ideal material for innovative fashion accessories.
〈Extension Reading: What is eco-friendly silicone? An analysis of its 4 key material advantages and applications!〉
Five common myths of silicone rubber
Is silicone rubber the same as plastic?
Although there are some common features between silicone rubber and plastic, in essence, they are completely different materials. Plastics have brought many problems to the environment and ecosystem. For example, plastics contain chemical poisons, which may enter people’s diets in various ways. Silicone rubber does not produce dioxin when it burns, and it does not release toxic substances during heating or use. It is a material that is highly environmentally friendly, which just solves the environmental and ecological crisis caused by plastics. That is the reason why silicone rubber has become so popular.
Is silicone rubber safe?
Organosilicon, which is the raw material of silicone rubber compounds, is recognized as having chemical stability. Silicone rubber will not react with food or beverages in contact with it. Therefore, many experts and authorities believe that silicone rubber is non-toxic and safe for use in food utensils. At present, there are no reported health hazards related to the use of silicone-made cookware on the market or in research reports, and they do not produce any harmful fumes. Therefore, silicone rubber is absolutely safe and non-toxic. Hearing this, everyone may have a question: Since silicone rubber is non-toxic, it should be taken as food-grade, right? Silicone rubber's resistance to ultimate temperature and chemicals means that it will not react with food or any medium encountered in production. However, only materials that meet FDA standards are considered "food grade" levels. Even silicone rubber will be classified into many categories according to product applications. The suppliers of silicone rubber raw material that GUSN works with are coming from well-known international brands. We have full range of materials available for your project. Choosing a safe and reliable brand of silicone rubber raw materials is the most critical progress in project development!
〈Extension Reading: Is Silicone Toxic? A Comprehensive Analysis of Silicone Safety〉
Will silicone rubber melt when heated?
First of all, we need to understand the physical reaction of silicone rubber when it is at a high temperature. Silicone rubber is a "Thermoset" polymer, that strengthens when heated, but cannot be remolded or softened after initial forming. In opposite, plastic is a "thermoplastic" polymer that can be reheated and remolded. It will turn liquid when the temperature increases, and get hard in shape after cooling down. In this way, we can understand why silicone rubber can withstand high temperatures without being deformed. We believe that people who care about health are worried that the silicone spatulas, spoons used for cooking will melt when heated. You can rest assured about this. In fact, the silicone cooking ware can withstand a high temperature of 230°C. The temperature of the oil during cooking does not exceed 200°C. On the contrary, the temperature resistance of plastic products does not exceed 140°C, which is far less safe and practical than silicone rubber.
Does silicone rubber turn yellow?
Presumably, everyone has the experience that after long-term use, the silicone phone case turns yellow. To exclude yellowing factors caused by bad habits such as coffee and tea stains. The yellowing of silicone-made products is purely the oxidation of the sulfide components inside or the oxidation caused by ultraviolet rays and sun exposure. However, this kind of yellowing is a natural reaction and does not affect the quality and lifespan of the product itself, but only affects the appearance. However, the silicone rubber itself is more or less anti-ultraviolet, so of course, there is more than one factor for yellowing. It may also involve factors such as the poor quality of raw materials, the quality of the production process, and the quality of vulcanizing agents. In short, choosing high-quality silicone rubber can ultimately reduce such problems.
Is silicone rubber electrically conductive?
Silicone rubber has a very high resistivity, that is, insulating properties. However, silicone rubber can be made electrically conductive by adding the conductive material, such as our exclusive silicone rubber strips (zebra connectors) It is produced in the same way to turn insulating silicone rubber into an outstanding medium to the PCB circuit board.
〈Extension Reading: Understanding Thermal Silicone Rubber: A Comprehensive Guide〉
Conclusion
Silicone rubber is non-toxic and is not a hazardous waste, making it the better choice. A basic tip for safe silicone rubber use: If you are going to use silicone rubber, be sure it is high quality with an official datasheet guarantee and does not contain any fillers. The raw material of GSUN used are only from reliable brands such as Shin-Etsu from Japan, Dowsil From the USA, and WACKER from Germany. We are committed to providing our clients with the optimal solution for the material choosing to enable them to continue business growth.
