The heat resistance of silicone rubber is also very outstanding. It can work for a long time at 180 ℃. It can withstand elasticity for several weeks or more even at a temperature slightly higher than 200 ℃. It can withstand a high temperature of more than 300 ℃ instantaneously. Silicone rubber has good air permeability, and the oxygen permeability is the highest among synthetic polymers.
◆ Silicone rubber has excellent heat resistance, cold resistance, ozone resistance and atmospheric aging resistance. It has good electrical insulation performance. The tensile strength and abrasion resistance are worse than ordinary rubber and have no oil resistance.
Neoprene rubber has good physical and mechanical properties, oil resistance, heat resistance, flame resistance, sunlight resistance, ozone resistance, acid and alkali resistance, and chemical reagent resistance. The disadvantage is poor cold resistance and storage stability. It has high tensile strength, elongation, reversible crystallinity and good adhesion. Resistance to aging and heat. Excellent oil and chemical resistance. Weather resistance and ozone aging resistance are only inferior to ethylene propylene rubber and butyl rubber. The heat resistance is equivalent to that of nitrile rubber. The decomposition temperature is 230~260 ℃, the short-term resistance is 120~150 ℃, and the long-term use is 80~100 ℃. It has certain flame retardancy. Oil resistance is second only to nitrile rubber. Good corrosion resistance to inorganic acid and alkali. Poor cold resistance and poor electrical insulation. The storage stability of raw rubber is poor, which will produce "self sulfur" phenomenon. The Mooney viscosity increases, and the raw rubber becomes hard.
Hydrogenated nitrile rubber (HNBR) is a kind of highly saturated elastomer obtained by special hydrogenation of nitrile rubber. Hydrogenated nitrile rubber has good oil resistance (good resistance to fuel oil, lubricating oil and aromatic solvent); And because of its highly saturated structure, it has good heat resistance, excellent chemical corrosion resistance (good resistance to Freon, acid and alkali), excellent ozone resistance, and high compression set resistance; At the same time, hydrogenated nitrile rubber also has high strength, high tear resistance, excellent wear resistance and other characteristics, and is one of the rubber with excellent comprehensive performance.
Nitrile rubber has excellent oil resistance, high wear resistance, good heat resistance and strong adhesion. Its disadvantages are poor low temperature resistance, poor ozone resistance, insulation performance and low elasticity. It can be used for a long time in 120 ℃ air or 150 ℃ oil. In addition, it also has good water resistance, air tightness and excellent bonding properties.
◆ It is commonly used in the seals or rubber parts used in the household appliances industry, the seals in the food machinery industry, or the seals on various products that contact with the human body.
