ingredients for pharmaceuticals
Table 5: Major rubber materials and their operational temperature ranges
A typical oil seal consists of three common parts: an outer ring, the sealing element, and a spring. The exterior metal ring component provides strength and rigidity to the oil seal in the bore or recessed groove. Attached to that ring is the sealing element. This flexible interior component of the oil seal, the O-ring, prevents any fluid leaks between the shaft and housing. A spring ensures the constant pressure that deforms the O-ring, creating a reliable seal while maintaining radial force on the shaft.
Metal inserts must be carefully prepared in operations involving cleaning and roughening surfaces (grit-blasting or phosphatizing), stamping out parts, application of primer (usually by dipping), and curing of the primer (often by baking for a short time at moderate temperature).3 Primer curing minimizes the possibility of wiping primer off portions of the insert by stock flow during molding. The treated metal inserts must be used within a relatively short time (usually a day or less), so that functionality necessary for bonding is not lost by reaction with moisture in the air. Freshness of the primer surface is particularly important for peroxide-cured and base-resistant fluoroelastomer compounds. Compound formulation should be adjusted to attain good adhesion.