NBR, Nitrile Butadiene Rubber is widely used in industrial and automotive fields such as sealing, rubber pipes, and rings due to its excellent oil resistance. However, the effects of different oils on NBR are different, and the performance will fluctuate with time and temperature. This article will analyze the oil resistance performance of NBR in different oil products, common test conditions and standards in different oil products, and help readers understand how to choose materials more scientifically to cope with complex environments.
1.the principle of oil resistance of NBR rubber NBR rubber is formed by governing acryl (an AN) and butadiene. It has excellent oil resistance. Its performance is directly related to the content of acrylite: -The high acrylite content (35%-50%): improves oil resistance and chemical resistance, but sacrificed low gentleness and elasticity. -The low-hydrite content (18%-25%): Enhanced low gentleness, but the oil resistance is slightly worse.
By controlling the ratio of acryl and butadiene, the performance of NBR can be adjusted to adapt to different oil environment. However, light hydrocarbons and polar molecules in oil products may cause NBR's swelling or hardening, so oil resistance testing is necessary.
2. Detailed explanation of oil product classification and test conditions 1. Mineral oil: lubricating oil, hydraulic oil, transformer oil test conditions-temperature: 100 ℃, 125 ℃-time: 72 hours, 168 hours
Measurement Indicators-Volume Change Rate-Hardness Change (Shaw's Hardness) -The stretch strength and fracture erection rate
Test performance-The swelling effect of paraffin base oil and cyclopecal oil is different, and the former has less influence on NBR. -The long-term high temperature contact may lead to a decrease in slight hardness and aging of materials. -In suggestion: Increase the acrylite content and increase the oil resistance and high temperature resistance of the material.
2. Fuel oil: gasoline, diesel, aviation kerosene test conditions-temperature: 23 ° C, 70 ° C-time: 24 hours, 96 hours-test standard: ASTM D471
Measurement indicators-volume change rate-quality change rate-stretch intensity and elongation rate
Test performance-gasoline: Due to the small molecular weight, it is easy to penetrate the NBR and cause significant expansion and reduce the hardness. -Diesel: The degree of expansion is slightly lighter than gasoline, but long contact time will accelerate aging. -Alipping kerosene: The erosion of NBR is gentle, but performance decline will also occur under high temperature conditions. -Igly: In the fuel system, it is recommended to use hydrogenated chores (HNBR) to replace NBR to improve oil resistance.
3. Synthetic oil: Test conditions for testing of phosphate hydraulic oil, polyether and ester oil-temperature: 100 ° C, 150 ° C-time: 96 hours, 168 hours-test standard: ISO 1817
Measurement indicators-volume change rate-stretch strength maintenance rate-hardness and fracture elongation rate
Test performance-phosphate hydraulic oil (such as Skydrol) has a strong corrosion of NBR, which will cause severe bloating and deterioration of rubber. -Colin and polyether contain polarity molecules, which exacerbate the aging of NBR, which is particularly obvious in high temperature environments. -Igly: When using this type of oil, you should optimize the NBR formula, or use other chemical rubber materials.
4. Testing conditions for carrier oil: coconut oil, soybean oil and other tests-temperature: 23 ° C, 70 ° C-time: 24 hours, 72 hours-test standards: ISO 1817
Measurement indicators-volume change rate-hardness change-broken elongation rate
Test performance-Animal and plant oil contains certain polarity molecules, and long-term contact can cause the NBR to expand slightly. -In high temperature conditions, the oxidation products of animal and plant oil may accelerate the aging of rubber. -The suggestion: Add antioxidants to delay the aging of materials, and adjust the acrylic content of the NBR appropriately.
5. Special oil products: Silicon oil, fluorite and other test conditions-temperature: 150 ° C or above-time: 72 hours to 300 hours-test standard: DIN 53521
Measurement Indicators-Stretch strength maintenance rate-volume change rate-quality change rate
Test performance-Silicon oil's bloating effect is lighter, but the mechanical strength of NBR will be reduced at high temperatures. -Feve oil is not compatible with NBR, which may lead to severe swelling and degradation. -Igly: When contacting special oils in high temperature environments, it is recommended to use multi-layer structure or protective coating.
3. Summary of test results and analysis of the type of oil type temperature range (℃) Test time The common phenomenon of testing is recommended to deal with measurement measures 23 ℃ -125 ℃ 72H-168H slightly swelling, decreased hardness, increases acrylonin content, increase oil resistance fuel oil 23 ° C- 70 ℃ 24H-96h significantly swelling, the stretching performance decreased consideration, HNBR replacing the synthetic oil 100 ℃ -150 ℃ 96h-168h severe aging, performance degradation, specialized formula optimization of animals and plant oils 23 ℃ -70 24h-72H sclerosis, mild swelling, added Antioxidant delay aging aging special oil above 150 ° C, 72H-300h, decreased, and severe bloating and coating surface protective layer
4. Future research and application direction With the continuous development of the needs of the industrial field, the research on oil resistance of NBR rubber still has room for improvement. Future research directions include: 1. Development of composite materials: combine NBR with other high -performance materials (such as HNBR and FKM) to improve high temperature resistance and chemical corrosion performance. 2. Surface treatment technology: Using nano -coating or functional coating to improve the oil resistance and service life of NBR. 3. Green formula design: Reduce the use of plasticizers and other additives that may affect the environment, and improve the environmental protection of materials. 4. Dynamic testing under high temperature conditions: Simulate durability under complex working conditions to meet the needs of high -end equipment.
NBR rubber has become an important material in various industrial applications with its excellent oil resistance. However, the effects of different oils on their performance are different. The rubber formula needs to be selected according to the specific application scenarios, and the oil resistance test and optimize. In the future, through innovation of technologies such as composite materials and surface treatment, the oil resistance of NBR rubber will be further enhanced to provide better material solutions for the development of the industrial field.