VMQ/SILICONE vs. FVMQ: Choose Materials That Suit Your Needs

1. Introduction

In the modern industrial field, material selection is crucial for product performance and applications. Especially in scenarios with high requirements for resistance or mechanical performance and subsequent maintenance, different types of rubber materials exhibit unique advantages. VMQ and FVMQ are two common materials that, although both belong to silicone-based rubbers, have significant differences in chemical structure, performance, and application fields. This article will explore the key differences between VMQ and FVMQ in detail, helping you better understand their respective advantages and suitable scenarios.

2. What is VMQ/SILICONE?

1. Composition and Structure:

VMQ, also known as Silicone Rubber, is an elastomer composed of a polysiloxane (Polysiloxane) backbone. Its basic chemical structure consists of alternating silicon (Si) and oxygen (O) atoms in the backbone, with organic side groups like methyl and vinyl attached to the silicon atoms. This structure gives silicone rubber excellent thermal stability and chemical inertness, allowing it to maintain elasticity at extreme temperatures.

2. Key Features:

VMQ silicone rubber is renowned for its outstanding high and low-temperature resistance, remaining stable across a temperature range of -60°C to 225°C, with special formulations that can be used between -100°C and 300°C. Additionally, silicone rubber has excellent electrical insulation properties and stability against heat oxidation and ozone. It is non-toxic and environmentally friendly, suitable for applications requiring high safety and hygiene standards. However, silicone rubber has relatively low mechanical strength, poor oil, solvent, and acid-alkali resistance, and a more complex vulcanization process.

3. Applications:

Due to its unique properties, VMQ silicone rubber is widely used in high and low-temperature applications, such as manufacturing hoses, seals, and insulation layers for high-temperature cables. Its non-toxic and odorless characteristics make it widely used in the food and medical industries, such as food-grade seals, baby products, and medical devices. In summary, silicone rubber is an ideal choice for any application requiring a combination of thermal stability, flexibility, and safety.

3. What is FVMQ?

1. Composition and Structure:

FVMQ is a special elastomer with a silicon-oxygen bond (Si-O) backbone and trifluoropropyl groups in the side chain. FVMQ is polymerized similarly to dimethyl silicone rubber, using a cyclic siloxane ring-opening polymerization process. This structure gives fluorosilicone rubber the temperature resistance of silicone rubber and the oil and solvent resistance of fluororubber, providing unique advantages under extreme conditions.

2. Key Features:

FVMQ has excellent oil and solvent resistance, particularly maintaining stability under normal and high temperatures against petroleum-based fuels, lubricants, hydraulic oils, and certain synthetic oils. Its operating temperature range is -60°C to 200°C, with long-term use possible within this range, and up to 180°C under oil immersion conditions. Although its heat resistance and drug resistance are slightly inferior to ordinary fluororubber, its unique silicon-oxygen bond and fluorine side chain structure make it perform well in fuel oil environments. Disadvantages include relatively low mechanical strength, general resistance to ethanol gasoline, and higher costs.

3. Applications:

FVMQ is widely used in the aerospace and automotive industries. In aerospace, it is used in harsh environments requiring low temperature, oil resistance, and acid resistance, such as fuel oil seals on aircraft, integral tank seals, and sensor materials. In the automotive industry, FVMQ is commonly used in vehicle seals, oil seals, diaphragms, ducts, valves, and other components, particularly in special vehicle door and window seals and sensor materials. Due to its superior performance, FVMQ is particularly suitable for applications that require stability under extreme conditions.

4. Performance Comparison: VMQ vs. FVMQ

1. Temperature Resistance:

– FVMQ: Maximum operating temperature of 200°C, low-temperature resistance down to -80°C.

– VMQ: Maximum operating temperature of 250°C, low-temperature resistance ranging from -70°C to -120°C.

VMQ performs better at high temperatures, while both perform similarly under low temperatures, though VMQ has a broader low-temperature range.

2. Stability and Chemical Resistance:

– FVMQ: Exhibits excellent resistance to fuels, oxygen, oils, and chemical solvents, especially in chemical solvents and fuel oils.

– VMQ: Shows good resistance to oxygen and chemicals but is less resistant to solvents compared to FVMQ.

FVMQ outperforms VMQ in chemical solvent, fuel oil, and combustion stability.

3. Mechanical Properties: Elasticity, Hardness, and Abrasion Resistance:

– FVMQ: Has good elasticity, a hardness range of 50-80 Shore A, with relatively weak abrasion resistance.

– VMQ: Also has excellent elasticity, with a wider hardness range of 30-90 Shore A, and slightly weaker abrasion resistance.

Both materials have similar elasticity, but VMQ offers a broader range of hardness options. In terms of abrasion resistance, both perform moderately, with FVMQ slightly better than VMQ.

4. Aging Resistance:

– FVMQ:Exhibits excellent aging, ozone, and oxygen resistance.

– VMQ: Also shows strong aging resistance, particularly under exposure to heat, oxygen, and ozone.

Both materials have excellent aging resistance, suitable for applications requiring long-term exposure to harsh environments.

5. Application Scenario Analysis

1. Performance in Different Applications:

VMQ and FVMQ each have unique advantages in their respective fields of application. VMQ is widely used in scenarios requiring long-term high-temperature, low-temperature, and good electrical insulation, such as insulation layers for wires and cables, seals, and food-grade and medical-grade seals. Due to its non-toxic and odorless properties, VMQ is also often used in applications that come into contact with food and the human body.

FVMQ, on the other hand, is particularly suitable for sealing and protective components in extreme environments, especially in the aerospace and automotive industries. It can maintain elasticity and stability for long periods when exposed to fuel oils, lubricants, hydraulic oils, and other oil products, making it ideal for aircraft fuel systems, oil tank seals, and automotive oil seals, diaphragms, etc.

2. Case Studies:

– VMQ (Silicone Rubber):

– Food and Medical Equipment Industry:

In food processing equipment, VMQ seals are widely used due to their high-temperature resistance, non-toxicity, and odorless properties. They can work long-term in steam environments without affecting the taste or safety of the food. For example, in high-temperature baking equipment, VMQ seals can work for extended periods at 200°C without significant performance degradation.

– Medical Equipment:

In medical devices like respiratory masks and catheters, VMQ is the material of choice due to its biocompatibility and resistance to disinfection. It can withstand repeated high-temperature disinfection treatments while maintaining softness and sealing properties.

– Electronics Industry:

In the electronics industry, VMQ is used to make insulating materials, such as high-temperature cable sheaths. Its heat resistance and excellent electrical insulation make it perform well in high-temperature electrical environments. For instance, the VMQ insulation layer in electrical equipment can operate at 250°C, ensuring the normal operation of the equipment.

– FVMQ (Fluorosilicone Rubber):

– Aerospace Industry:

FVMQ is extensively used in the aerospace industry. For example, in an aircraft’s fuel system, FVMQ seals can maintain good sealing performance under extreme temperature variations (-60°C to 200°C), resist fuel oil corrosion, and prevent fuel leakage. A typical case is a certain model of passenger aircraft fuel system, where FVMQ seals have maintained excellent elasticity and oil resistance after long-term use, avoiding material aging and fuel leakage problems that could occur with conventional rubber.

– Automotive Industry:

In automotive manufacturing, FVMQ is used to make various critical seals, such as engine oil seals and fuel system seals. FVMQ can effectively resist the high temperatures and chemical erosion of engine lubricating oil, extending the lifespan of seals. In high-performance racing cars, FVMQ is often used as an oil seal material due to its oil resistance and high-temperature resistance, ensuring the normal

operation of the engine.

– Oil and Chemical Industry:

In the oil and chemical industries, FVMQ is used in oil pipelines and chemical containers that require sealing and protective components to resist chemical corrosion and maintain stable performance at high temperatures. For example, in a chemical plant’s reactor system, FVMQ seals provide excellent sealing performance and chemical resistance, maintaining the system’s tightness during chemical reactions and avoiding safety issues such as leaks.

6. Cost

1. Cost Comparison:

– VMQ: VMQ is generally more cost-effective and is available in various formulations to suit different budgets and performance requirements.

– FVMQ: Due to its specialized performance characteristics, FVMQ is typically more expensive, with costs driven by its unique resistance properties and use in high-performance applications.

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7. Selection Recommendations

1. Recommendations Based on Application Needs:

– Choose VMQ if:

– You require high-temperature resistance in applications like electrical insulation or food-grade materials.

– Cost is a significant factor, and the environment doesn’t demand high chemical or oil resistance.

– Choose FVMQ if:

– Your application involves exposure to harsh chemicals, fuels, or extreme temperatures.

– You need a material that can maintain performance in aerospace or automotive environments.

8. Conclusion

Jingteng Seiko—a leader in the fluid control industry—offers tailored solutions for automotive, medical, food, and other sectors. We uphold the highest standards in material selection and precision craftsmanship, ensuring every product undergoes rigorous testing before delivery. With a commitment to 100% reliability, Jingteng Precision ensures your equipment operates efficiently and effectively.

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Data of air/liquid flow, aging, high & low tempreture, chemical resistent test etc.