Resistance to Various Fluids

CR possesses medium oil resistance making the polymer suitable for articles resistant to intermittent oil exposure or exposure to less aggressive oils such as paraffinic and napthenic oils or corresponding hydraulic oils. The resistance to regular fuels is limited, and insufficient in fuels with high aromatic content. 

Additives in oils may cause hardening of vulcanizates. CR, however, proves to be more stable than a typical NBR vulcanizate. 

Unless a lead oxide cure is used, CR compounds can fail to meet severe water resistance requirements. The use of a lead oxide cure allows limited swell in water, so that volume changes of only a few percent can be obtained. Properly compounded CR also exhibits good resistance to dilute acids and alkaline solutions at moderate temperatures. 

A list of the swell resistance in various chemicals is given in Table 1.12. 

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