sharpening agent

To increase the speed of unhairing and to lower hair retention rates, sharpening agents are added.

Excessive sharpening agent result in hair pulping.

The hydrogen atoms supplied by the sharpening agent weaken the cystine molecular link whereby the covalent disulfide bond links are ultimately ruptured, weakening the keratin.

Controlled exposure of sharpening agent, or other alkali, to the hair will result in hair-save unhairing (during which the hair can be removed intact from the process vessel).

After soaking, the hides and skins are taken for liming: treatment with milk of lime (a basic agent) that may involve the addition of "sharpening agents" (disulfide reducing agents) such as sodium sulfide, cyanides, amines, etc.