O-ring performance is different, how do we choose the formula?

In our lives, O-rings are widely used, according to the different uses, its performance, we will take into account many factors, such as hardness, elongation, compression and so on. Of course, the specific performance, we can always according to customer requirements or O-ring working environment to judge, and then customize the customer's exclusive rubber material. So different roles of O-rings, how should we choose the formula?


According to the different pressure in the sealing system, different hardness of O-ring sealant was designed. High pressure should choose high hardness adhesive, low pressure is selected medium hardness or low hardness adhesive. In order to improve product quality and service life, the hardness of rubber compound has been serialized in the national standard. For example, the nitrile butadiene rubber used in hydraulic systems, in addition to special requirements, the hardness of the rubber material is divided into 60° 5°, 70° 5°, 80°+5°, 88° Earth 5°(Shore A) four hardness levels to meet the requirements of different pressures. Generally, 60~0 is low hardness, the product is medium hardness, 88 is high hardness, and the sealing pressure is in the range of 30~ 60MPa, the hardness of the O-ring is 85~90 is more appropriate.


As an O-ring used as a seal, in addition to considering the hardness of the rubber material, it is also required that the rubber material must have good comprehensive properties, and the compression permanent deformation should be small, especially the high hardness rubber material, good process performance is also essential. The design of high hardness compound generally requires a large amount of carbon black, and a large amount of carbon filling will bring difficulties to the rubber refining process, and the heat generated in the rubber refining process is large, and the rubber is easy to burn. At the same time, a large amount of carbon black will reduce the elasticity of the rubber material and increase the permanent compression deformation. Therefore, the selection and coordination of vulcanization system and filling system in the compound formula is very important. As far as nitrile rubber is concerned, in order to improve the heat resistance of the compound, reduce the permanent deformation of compression, and improve other properties, low sulfur (less than 0.5 parts) high speed and sulfur free and peroxide vulcanization systems are currently used. The vulcanized rubber has good physical and mechanical properties and heat resistance, small compression and permanent deformation, and is not easy to burn.


In terms of the design of medium hardness and low hardness compound formula, in line with the principle of simplifying the series compound formula as far as possible, and striving to reduce the basic formula on the basis of the method of increasing the amount of carbon black and softener, the design and test out the medium and low hardness grade compound, in order to achieve the purpose of convenient production management and satisfying the use requirements.


Different formulations of the O-ring, the performance of the function is not the same, our Forever Seals will be according to customer requirements, or according to the specific use of the O-ring to customize the formula. We have professional engineers to tailor your O-ring to meet your needs.


If you have other questions, please visit the Forever Seals official website for consultation www.freseals.com


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