The different application of Oxidized Bitumen 

It is hypothesized that leakage results from the inability of the sealant, or sealants, to adequately bond to the metal surface.  

Even cured epoxy-polyamine resins, though non-tacky, are relatively soft and can cause problems during cell assembly. 

Others, attempting to improve upon the seals of alkaline batteries have used sealants consisting of fatty polyamides or both oxidized bitumen and fatty polyamide resins, all of these solutions have the same drawback--leakage still occurs since these materials do not always completely seal the interface of the metal surface and the gasket. 

Moreover, sealants such as oxidized bitumen and fatty polyamides are soft, somewhat tacky materials at and above room temperature and so are subject to damage and contamination during the assembly of electrochemical cells.