Since the 1970s, Liquid Silicone Rubber (LSR) has emerged as a top choice in the manufacturing of silicone products and components. It has found extensive applications across multiple industries, such as automotive, medical and life sciences, baby products, and consumer goods. Thanks to its unique chemical composition and outstanding properties, LSR has firmly established its significance in these fields. Now, let’s delve into the properties of LSR and understand why it could be the optimal material for your products.
3 Reasons to Opt for Liquid Silicone Rubber (LSR)
When selecting materials for manufacturing crucial and durable components, LSR is definitely worth considering.SHENGHUI is a leader in the field of liquid silicone rubber injection molding. Since its establishment in [Founding Year], LSR has been the primary material we process in various injection molding techniques, including LSR injection, two-shot injection, multi-shot injection, and overmolding. With SHENGHUI’s extensive experience over the years and a team of professionals, we are undoubtedly the best partner to meet your silicone component requirements. Moreover, we excel in providing customized value – added solutions to precisely match customers’ specific needs.
The characteristics and chemical properties of LSR make it an ideal material for a wide range of industrial applications. If you want to learn more about LSR and its advantages, keep reading. You can also directly contact SHENGHUI to discover how our expert team can offer you value – added solutions.
1.Chemical Composition of Silicone Rubber: The unique physical properties of silicone rubber stem from its chemical structure. Silicone rubber is an elastomer mainly composed of a molecular chain known as the siloxane bond (-Si – O – Si -). This chain serves as the “backbone” of silicone rubber, and various organic chemical groups can be attached to it, thereby altering the mechanical and material properties of the silicone rubber.
One of the significant differences between silicone rubber and other elastomers lies in the strength of the siloxane bond. While the binding energy of a carbon – carbon bond is 355 kJ/mol, the siloxane bond has a strength of 433 kJ/mol. This gives silicone rubber better heat resistance, chemical stability, and electrical insulation.
At the same time, the intermolecular forces of silicone bonds are relatively low, allowing other chemical groups attached to them to rotate freely. As a result, liquid silicone rubber exhibits high elasticity, compressibility, resilience, and weather resistance.
2. Mechanical Properties of LSR: Different grades of silicone rubber possess diverse material properties. This versatility is one of the reasons why LSR is widely used in numerous fields. Whether you need medical products for drug delivery or pumping applications that require strength, flexibility, and repeatability, or automotive components that must endure high temperatures and vibrations, the mechanical properties of LSR make it an excellent material choice.
Key material properties of silicone rubber include fast curing, low compression set, tear resistance, heat resistance, water resistance, oil resistance, transparency, electrical insulation, as well as excellent overall strength and long service life. LSR can be used in a temperature range from – 40°C to 200°C (- 40°F – 392°F). It can be exposed to wind, rain, and ultraviolet light for extended periods or immersed in water, oil, or solvents. The material properties of different LSR grades are sufficient to meet the most demanding application scenarios.
3. LSR Provides Innovative Solutions to Engineering Challenges: LSR is waterproof and does not decompose when in contact with solvents. It is available in multiple hardness levels and a wide range of colors, making it a versatile material for various products. The low – viscosity property of LSR enables it to flow smoothly during the injection molding process, making it highly suitable for multi – cavity molds used in high – volume production. For products with intricate design features such as undercuts, thin walls, small components, and complex geometries, LSR makes production easier, providing greater flexibility and creativity for product designers.
Application Fields of Liquid Silicone Rubber
LSR components are widely used in many different industries. Its resistance to steam, heat, and moisture, as well as its high purity, make it an ideal choice for components that need to be manufactured in a hygienic environment with environmental control (such as an ISO clean room) and may require sterilization. Gaskets, seals, and diaphragms used in gas appliances and other household appliances (such as dishwashers, gas furnaces, and water heaters) must function properly in extreme temperatures and environments. Many automotive components require oil resistance, heat resistance, excellent sealing performance, shock absorption, and insulation properties. Therefore, LSR is used in various parts of a vehicle, including under the hood, in electric vehicle battery packs, sensors, and electrical connectors throughout the vehicle.
Properties of LSR Components
The specific material properties of LSR are attributed to its unique chemical structure. Its backbone is composed of a series of siloxane bonds, which are stronger and more stable compared to carbon – carbon bonds. This endows LSR with many excellent properties:
- Chemical Inertness: LSR has an organic backbone, making it chemically inert. It does not react with other chemical substances. It can also resist damage from water, oxidation, ultraviolet light, ozone, radiation, and various alkaline or acidic products. For products that need to be frequently cleaned, are exposed to water and moisture, are used outdoors, or are in other harsh environments, the chemical properties of LSR enable it to perform well under these conditions.
- Hypoallergenicity: LSR is inherently hypoallergenic and non – toxic. It will not cause irritation or allergic reactions even when in contact with sensitive skin. For respiratory products such as oxygen masks and CPAP masks, as well as products like earbuds, hearing aids, or wearable monitoring devices that are worn for long periods, LSR provides a safe and comfortable solution.
- Biocompatibility: The molecular structure of LSR also contributes to its biocompatibility. It is odorless and tasteless. Meeting the requirements of the Food and Drug Administration (FDA), it is widely used in baby products and other food – and beverage – related products.
- Physical Properties: LSR exhibits excellent physical and thermal stability, which is why it is more favored than other elastomeric polymers. Depending on the grade, LSR can maintain its physical properties within a wide temperature range from – 40°C to 200°C.
In addition, LSR has the following physical characteristics:
- Compression Set: LSR components can maintain their original shape after compression.
- Surface: LSR has a naturally smooth texture.
- Modulus: LSR offers a balance of flexibility and rigidity.
- Sealing Performance: LSR is widely chosen for its excellent sealing properties.
- Responsiveness: It is highly sensitive and responsive, making it an ideal material for precision sensing membranes.
- Insulation: LSR has natural electrical and thermal insulation properties.
- Hardness: It is available in a variety of hardness levels, with the most commonly used being Shore A hardness from 10 to 80.
LSR molded parts are odorless and tasteless. By using pigments and masterbatches, unique colors and visual effects can be achieved. These parts are also resistant to ozone and ultraviolet light. Other notable features of LSR parts include: resistance to steam and humidity, flame retardancy, low creep and compression set, weather resistance, shock absorption, corrosion resistance, resistance to mold, mildew, and bacteria growth, UL component recognition, and more.
There are various types of LSR available on the market to meet the potential application requirements of a wide range of industries. If you want to learn more about the specific properties of different LSR products, feel free to contact SHENGHUI and communicate with our in – house engineers.
Application Examples of Liquid Silicone Rubber
You may be wondering what specific products LSR is used in. LSR is an extremely versatile material, and new applications are being explored and tested every day. It is a crucial material in many markets, such as healthcare manufacturing, automotive component manufacturing, electronics and consumer goods, gaskets and other hardware.
Typical LSR products manufactured by SHENGHUI for customers include: valves for intravenous infusions and fluid handling equipment, diaphragms in pumps and regulators, gaskets and seals in connectors, components of handheld surgical instruments, syringe stoppers and septa, ear tips for hearing aids, needle – free valve sights, bellows and membranes, skin – contact devices, soft – touch buttons/surfaces, steam – sterilized parts, seals for housings and covers, and more.
These components play various roles in different industries. In the healthcare field, the biocompatibility, hypoallergenicity, and hygienic properties of LSR are of great importance, so it is used in products such as syringes, surgical sleeves, masks, and respirators. Home appliance or automotive manufacturers may value its heat and vibration resistance and use LSR for gaskets, seals, and other connections. Safety products rely on the durability of LSR, and consumer product manufacturers often use it to protect sensitive electronic components from moisture and vibration, such as in blenders and toothbrushes.
The applications of LSR are numerous. Its design flexibility allows for a high degree of customization. It can be formulated differently and molded into small components and complex geometries, which is essential for many precision applications such as automotive parts and special products. You can find LSR in industrial settings, hospitals, cars, laboratories, and ordinary households. If an application requires a material that is safe, durable, and customizable to specific needs, LSR is often a common choice.
Custom LSR Solutions for Your Business
SHENGHUI was an early pioneer in LSR injection molding and ranks among the top silicone injection molding companies globally. We have produced billions of liquid silicone rubber parts since 2002 and we offer our customers a full portfolio of value-added services from prototyping through high-volume LSR, LSR multi-shot and LSR over-molded parts production, to inline value-added secondary processes. Our 20 years of experience, advanced LSR molding technology and ISO 9001, ISO 13485, and IATF 16949 certified quality allow us to offer you extraordinary solutions and consistent quality parts and service you can rely on.
SHENGHUI For more information about LSR and LSR injection molding. Contact us today to discuss how SHENGHUI can offer a tailored solution to meet your specific product requirements.