O ring rubber formulation design

2019 - O ring rubber formulation design 11 - 13 ( A) Main performance requirements should be according to the working conditions of the o-ring as medium, temperature, pressure, stress and other rubber formulation design. Used as a static sealing o-ring rubber, the key performance index is medium resistance and compression set. As dynamic sealing o-ring, besides small medium resistance, compression set, also require rubber has a good tear resistance, abrasion resistance, heat resistance and compression resistance ( Have adapted to working pressure hardness) 。 （ 2) 1 formula design points. Analysing choice according to the working medium of the o-ring and to choose suitable analysing working temperature. Working medium for fuel oil, hydraulic oil, engine oil, lubricating oil and other oil, working temperature below 150 ℃, how choose NBR; When using a temperature higher than 150 ℃, can choose hydrogenated nitrile rubber, fluorine rubber, fluorinated silicone rubber, etc. When working medium for phosphate or too hot, can choose ethylene propylene rubber; Working medium for acid, alkali, salt and other low concentration chemical corrosive medium, and using the temperature does not exceed 100 ℃, can make the rubber, natural rubber, styrene-butadiene rubber, and other general and high concentration of strong corrosive medium should choose fluorine rubber; Used in high temperature hot air, we can use silicone rubber o-ring. 2. Vulcanization system using organic peroxide ( Such as DCP) Nitrile rubber vulcanization, with a small compression permanent deformation, heat resistance, low temperature resistant performance is good, not easy to scorch and storage as well as good security, and its defect is low elongation, hot tear performance is poor, curing speed slow. In order to overcome the above shortcomings, can choose low sulfur or sulfur, DCP - may be adopted Sulfur/accelerator composite vulcanization system. Commonly used accelerator DM, CZ, TMTD, EZ, etc. 3. Filling system generally according to the working pressure to determine the o-ring rubber hardness, high working pressure, hardness is high, and vice versa. O-ring Shao Er A hardness of the rubber, divided into 60 & plusmn; 5,70 ± 5,80 ± 5,90 ± Five four levels. To meet the requirements of different hardness o-ring, commonly used to increase or reduce the dosage of carbon black carbon black methods to achieve. Using hot crack of black carbon black or spray rubber compression permanent deformation of small, low heating, large contact pressure, the o-ring sealed performance is good. But to get Shao Er A hardness of 90 & plusmn; 5 high hardness rubber, requires a large amount of filling ( More than 120 quality copy) , will bring difficulties to mixing process, and will make other physical properties of rubber is reduced. Therefore, for high hardness of the o-ring rubber, can choose high wear-resistant carbon black or with a reinforcing carbon black, fine particle cracking carbon black ( 英国《金融时报》) , etc. Thickener can be matched with the right amount of hard, such as in vinegar, methylacrylic acid magnesium, etc. 4. Softener is based on NBR o-ring rubber, is the most commonly used plasticizer sebacic acid, dibutyl phthalate, dibutyl phthalate esters plasticizer dioctyl ester, etc. 5. Stabilizer was pulled out of the stabilizer should be chosen to be medium, such as the reaction type stabilizer. Commonly used antiager have antiager MB, RD, 4010, 4010, na and antiager A, antiager D, etc. （ 3) Formula sample NBR o-ring rubber formula examples are shown in table