Nitrile Butadiene Rubber (NBR), a copolymer of butadiene and acrylonitrile, has found wide – spread application in the production of clutch facings. As a key component in clutch facings friction materials, it plays a vital role in the performance and quality of clutch facings. NBR interacts closely with clutch facings mixtures and clutch facings mixes, influencing the overall characteristics of the final product.

NBR is added to the clutch facings mixture mainly to enhance its bonding properties and flexibility. In the clutch facings production process, it acts as a binder that holds together various components in the clutch facings mixes, such as fibrous materials and friction – enhancing fillers. Typically, NBR content in the clutch facings mixture ranges from 10% – 30% by weight, depending on the specific requirements of the clutch facings.

One of the most prominent features of NBR is its outstanding oil resistance. In a laboratory test, when exposed to common lubricating oils for 1000 hours at 100°C, the volume swelling of NBR – based clutch facings was less than 5%. This is crucial for clutch facings as they often come into contact with engine oils during operation. Good oil resistance ensures that the clutch facings maintain their mechanical and friction properties, extending the service life of the clutch.

NBR – modified clutch facings friction materials exhibit high friction stability. In a friction coefficient test conducted under different pressure and speed conditions, the friction coefficient of NBR – containing clutch facings remained within a relatively stable range of 0.3 – 0.45. This stable friction performance provides reliable power transmission and smooth operation of the clutch system.

NBR endows the clutch facings with good flexibility. This allows the clutch facings to adapt well to the uneven surfaces of the clutch plates during engagement and disengagement. In a durability test, NBR – based clutch facings could withstand over 100,000 engagement – disengagement cycles without significant wear or damage, indicating their high durability.

Although NBR has many advantages, its heat resistance is relatively limited. When the temperature exceeds 150°C, the mechanical properties of NBR – based clutch facings start to degrade rapidly. In a heat – aging test at 180°C for 100 hours, the tensile strength of NBR – containing clutch facings decreased by about 30%. This restricts the application of NBR – based clutch facings in high – temperature – demanding clutch systems.

The production cost of NBR is relatively high compared to some other rubbers. In the production of clutch facings, the high cost of NBR can increase the overall production cost by about 15% – 25%, especially when the NBR content in the clutch facings mixture is relatively high. This cost factor may pose challenges for manufacturers aiming to produce cost – effective clutch facings.

In conclusion, Nitrile Butadiene Rubber offers significant advantages in the production of clutch facings, especially in terms of oil resistance and friction stability. However, its limitations in heat resistance and high cost need to be carefully considered when choosing materials for clutch facings friction materials.