Oil-resistant rubber Oil resistance usually refers to resistance to non-polar oils: fuel oil, mineral oil and synthetic lubricants. Rubber is classified according to oil resistance (polar rubber): CR, NBR, HNBR, ACM, AEM, CSM, FKM, FMVQ, CO, PUR. Non-oil-resistant rubber classification (non-polar rubber): NR, IR, BR, SBR, IIR, EPR, EPDM. Fuel resistance: Fluororubber FKM and fluorosilicone rubber FMVQ have the best resistance to fuel oil. Chloroprene rubber and chlorinated polyethylene rubber CPE have the worst fuel resistance. The fuel resistance of nitrile rubber increases with the increase of acrylonitrile content. The fuel resistance of epichlorohydrin rubber is better than that of nitrile rubber. Resistance to mixed fuels: Fluororubber FMVQ and fluororubber FKM have the best resistance to mixed fuel oils. Acrylic rubber has the worst resistance to mixed fuels. The resistance of nitrile rubber to mixed fuels increases with the increase of acrylonitrile content. Fluorine rubber with high fluorine content has better stability to mixed fuel. Rubber type Gasoline/methanol 85/15 Gasoline/ethanol 85/15 Average swelling degree (54 degrees)/% Average swelling degree (54 degrees)/% ECO 92 74 NBR 89 61 FMVQ 25 22 VITON A/FPM2601 23-28 16-20 VITON GH 19 15 BITON VI-R-4590 13 13 Resistance to acidic oxidized fuel: For acidic oxidized fuel, the hydroperoxide in the acidic oxidized fuel can deteriorate the performance of the vulcanized rubber, so the commonly used nitrile rubber and chlorohydrin rubber in the fuel system are difficult to meet the requirements of long-term use. Only fluorine-containing elastomers such as fluororubber FKM, fluorosilicone rubber FMVQ, fluorinated phosphorus nitrile and hydrogenated nitrile rubber have better performance. Ordinary nitrile rubber cannot work for a long time in 125-degree acidic gasoline. Only nitrile rubber with low sulfur-donating body activated by cadmium oxide and white carbon black as main raw materials can better resist acid gasoline. Increasing the content of acrylonitrile can reduce the permeability of acid gasoline. Mineral oil resistance: Nitrile rubber is a commonly used mineral oil resistant rubber. The mineral oil resistance of nitrile rubber increases with the increase of acrylonitrile content. However, the heat resistance of nitrile rubber with high acrylonitrile content is limited. When the oil temperature reaches 150 degrees, hydrogenated nitrile rubber, fluororubber FKM, fluorosilicone rubber FMVQ and acrylate rubber should be used. When the oil temperature reaches 150 degrees, fluororubber FKM and fluorosilicone rubber FMVQ have the best effect. However, the cost is high. In order to reduce the cost, less than 50% of acrylate rubber can be incorporated into fluororubber FKM, and the performance of the vulcanized rubber after use will not decrease by more than 20%. Acrylic rubber has better mineral oil resistance than nitrile rubber. Ethyl acrylate type rubber Acrylic rubber has better hot oil resistance than butyl acrylate type rubber. Resistance to synthetic lubricants: Principle of like dissolves like: polar polymers dissolve in polar solvents, and non-polar polymers dissolve in non-polar solvents. EPDM rubber is a hydrogen rubber and expands extremely in hydrogen oils. Silicone rubber in silicone oil and fluororubber in perfluorinated hydrogenated liquids all expand greatly in volume. Resistance to synthetic hydrogen lubricants: The oil resistance of nitrile rubber increases with the increase of acrylonitrile content. Aromatic hydrogen has a greater effect on the expansion of nitrile rubber than aliphatic hydrogen. Nitrile rubber with high acrylonitrile content is used to resist synthetic hydrogen oil with high aromatic hydrogen content. Nitrile rubber with medium acrylonitrile content is used to resist synthetic hydrogen oil with low aromatic hydrogen content. Nitrile rubber with low acrylonitrile content is used for synthetic oils such as paraffin oil used for low expansion. Or where low-temperature flexibility is more important than oil resistance. Using hydrogenated nitrile rubber can improve heat resistance, ozone resistance and resistance to additives. Hydrogenated nitrile rubber is suitable for hot oil resistance of 140-150 degrees. Oil and heat resistance is between nitrile rubber and fluororubber. Fluororubber can withstand long-term operation in synthetic hydrogen lubricants at 200 degrees. Silicone rubber can withstand long-term operation in synthetic hydrogen lubricants at 200 degrees. And it maintains good flexibility at -60 degrees. It is good for both paraffin oil and PAOS. But it is not resistant to low-viscosity synthetic hydrogen oils. It will expand greatly. Chlorohydrin rubber can withstand long-term operation in synthetic hydrogen lubricants at -40 to +120 degrees, with low air permeability and good ozone resistance. The disadvantages are corrosion to the mold and reversion after high-temperature aging. The ability of chlorosulfonated polyethylene rubber to resist synthetic hydrogen lubricants increases with the increase of chlorine content. In the range of -20 to +120 degrees, it can only be used in high-paraffin mineral oil and PAOS, and expands greatly in cyclohexane oil and aromatic hydrogen oil. Polyurethane rubber AU/EU/ can also resist synthetic hydrogen lubricants, but its compression deformation tends to deteriorate with increasing temperature (over 70 degrees). In addition, it has poor hydrolysis resistance. Resistance to polyalkylene glycol (PAG) synthetic lubricants In general, properly formulated NBR, chloroprene rubber, and EPDM vulcanizates can resist PAG synthetic lubricants. However, chloroprene rubber and EPDM are not resistant to mineral oils. If there is even a little mineral oil in the system, it may cause extreme swelling. Fluororubber is not resistant to PAG synthetic lubricants. Resistance to organic ester synthetic lubricants There are two types of organic ester synthetic lubricants: dicarboxylic acid esters and polyol esters. Usually, appropriately matched NBR and fluororubber are selected to resist phosphate ester synthetic lubricants Silicone rubber can resist phosphate ester synthetic lubricants, but its physical properties are very poor and its use is limited. EPDM and butyl rubber can only resist pure phosphate esters. If a small amount of mineral oil is mixed in, it will swell. Fluororubber is not resistant to phosphate ester synthetic lubricants EPDM, EPDM and butyl rubber can work for a long time in phosphate ester synthetic lubricants below 121 degrees. Resistance to synthetic lubricating oil containing silicon Generally, silicone oil is not easy to cause rubber expansion, but it can extract plasticizers in rubber. Non-plasticizer-containing styrene-butadiene rubber, EPDM rubber, NBR rubber, hydrogenated NBR rubber, and fluororubber are all resistant to silicone liquids. Resistance to fluorinated element oil Polyperfluorohydrogen ether is a non-flammable liquid that can be used in the temperature range of 230-260. Among the known rubbers, none can work for a long time in this temperature range. EPDM rubber can be used in fluorinated element oil at 100 degrees. Fluororubber can be used at 150 degrees. Resistance to polyphenyl ether liquid Polyphenyl ether is the most radiation-resistant liquid and is extremely stable to high temperature and oxidation. EPDM rubber can be used in polyphenyl ether at 100 degrees. Fluororubber can be used at 200 degrees. But fluororubber is not radiation-resistant. Resistance to hydrogen chloride liquid Hydrogen chloride synthetic liquid is a non-water-based flame retardant liquid. Fluororubber and silicone rubber work well. The matching system of oil-resistant rubber 1. Vulcanization system In general, increasing the crosslinking density can improve the oil resistance of vulcanized rubber. In oxidized fuel oil, nitrile rubber vulcanized with peroxide or semi-effective vulcanization system has better oil resistance than sulfur vulcanization. The stability of nitrile rubber vulcanized with peroxide vulcanization system is best at 40 degrees, but it is not ideal in oxidized fuel oil at 125 degrees. However, nitrile rubber vulcanized with cadmium oxide and sulfur donor system has better resistance to long-term heat aging in oxidized fuel oil at 125 degrees. 2. Filling system and plasticizer Adding carbon black and white carbon black can improve oil resistance. Softeners should be selected that are not easily extracted by oils. It is best to use low molecular polymers, such as low molecular polyethylene, oxidized polyethylene, polyester plasticizers and liquid rubber. Softeners or plasticizers with large polarity and large molecular weight are beneficial to oil resistance. 3. Anti-aging agents are mainly added antioxidants that are not easily extracted. DNP/SANTO FLEX IP/FLEXZONE 3C>> Common chemical product common name and scientific name comparison table (I) Common chemical product common name and scientific name comparison table (II) Overview of various thermosetting resins Definition and classification of resins TPU film/sheet applicable industries Definition and classification of resins