Which Type of Rubber is Best Suited for Suspension Bushings
Frequently, customers ask: "There are many types of rubber; which type does Yunqi use in its products?"
Frequently, customers ask: "There are many types of rubber; which type does Yunqi use in its products?"
Firstly, let's take a look at the classification of rubber formulations. Based on the primary purpose of rubber formulation design, formulations can be divided into basic formulations, performance formulations, and practical formulations.
P1: Basic Formulations
Basic formulations, also known as standard formulations, typically represent the minimum required combination of raw materials needed to convert a certain type of rubber into an elastomer. This formulation serves as a standard for studying and identifying the basic process and physical-mechanical properties of new types of rubber and new compounding agents. Based on the basic formulation, further improvements, optimizations, and adjustments can be made to achieve formulations with specific performance requirements. Although different departments may have varying basic formulations, the basic formulation for the same type of rubber is generally quite similar.
Common Types of Rubber:
Natural Rubber (NR)
Advantages: Excellent resilience, high strength, good tear and abrasion resistance, good elasticity for snapping, good low-temperature flexibility, and good adhesion to fabric or metal.
Disadvantages: Poor resistance to heat, ozone, and sunlight, and insufficient resistance to oil, gasoline, and solvents.
Applications: Typically used in suspensions, bushings, and tires.
Styrene-Butadiene Rubber (SBR)
Good resilience, excellent impact strength, good tensile and wear properties;
However, poor resistance to ozone and sunlight exposure, as well as poor resistance to oil, gasoline, and solvents;
Low cost, used in general large-scale polymer applications.
Butyl Rubber (IIR)
Advantages: Excellent impermeability to gases and steam, high energy absorption (high damping), good resistance to ozone and sunlight exposure, good heat and oxidation resistance, and good resistance to water and steam.
Disadvantages: High compression set, poor elasticity, and poor resistance to oil, gasoline, and solvents.
Applications: Used in vehicle bodies, cabins, subframe bushings, bumper blocks, etc.
Ethylene Propylene Diene Monomer (EPDM)
EPDM is an excellent rubber vibration-damping material, widely used in various vibration-damping products. It has good resistance to oxidation, ozone, and corrosion. EPDM adapts well to harsh climates, with stable physical properties and low cost. It is easy to vulcanize and has good adhesion when bonding to metal.
The disadvantage of EPDM is that its high-temperature resistance is inferior to VQM, with a maximum operating temperature of 150°C.
Chloroprene Rubber (CR)
Advantages: Good fire resistance, moderate oil and gasoline resistance, good adhesion to metal, good weathering, ozone, and aging resistance.
Disadvantages: Average low-temperature flexibility.
Applications: Hose covers, mounts, etc.
Silicone Rubber (VQM)
VQM has a silicon-oxygen chain structure with a bond energy of 443.5 KJ/MOL, much higher than the average carbon-carbon bond energy. As a result, VQM has excellent high and low-temperature resistance, with an operating temperature range of -60°C to 300°C. VQM also has good ozone resistance and biological inertness, preventing oxidation failure and avoiding the release of harmful substances during use. However, its mechanical strength is relatively weak. Therefore, it is generally used in the hot end of exhaust systems, some high-temperature-resistant power dampers, and, as recently reported, even in the main spring of hydraulic mounts.
P2: Performance Formulations
Performance formulations, also known as technical formulations, are designed to meet specific performance requirements. The goal is to satisfy both the product's performance and process requirements while enhancing certain characteristics. Performance formulations build upon basic formulations by thoroughly considering various performance factors to meet the demands of the product's usage conditions. When developing new products, the experimental formulations used are typically performance formulations, making them the most commonly utilized by formulation designers. However, these formulations may not always meet the comprehensive requirements of production.
P3: Practical Formulations
Practical formulations, also known as production formulations, consider a wide range of factors, including performance, processability, cost, and equipment constraints. The final practical formulation selected should be capable of meeting industrial production conditions, achieving an optimal balance between product performance, cost, and manufacturing processes. Formulations developed in laboratory conditions might not necessarily yield final results, as production may encounter technical challenges. In such cases, the formulation may need further adjustments to maintain the desired basic performance. Practical formulations must ensure the quality of the finished product while also considering the suitability of the formulation across all stages of the production process under existing conditions.
P4: Our Formulation
At Yunqi, we utilize a proprietary rubber formulation that we have developed in-house. This practical formulation meets OEM requirements and is designed from a product-oriented perspective. It is based on natural rubber, with a unique blend that enhances the original properties while improving resistance to heat, ozone, and sunlight, as well as addressing the limitations in resistance to oil, gasoline, and solvents. Our formulation strikes the optimal balance between physical and mechanical properties, performance, processability, and cost-effectiveness. Yunqi is committed to continuous research and development to further improve our products, ensuring we deliver superior quality to our customers.