Unhairing and Liming of hides and skins

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General description

The aim of unhairing and liming is to remove the hair, epidermis, and to some degree, the interfibrillary proteins, and to prepare the hide or skin for the removal of adhering flesh and fat by the fleshing process.

Hair removal is performed by chemical and mechanical means. The keratinous material (hair, hair roots, epidermis) and fat are traditionally eliminated from the pelts mainly with sulphides (NaHS or Na2S) and lime. Alternatives to inorganic sulphides include organic sulphur compounds such as thioles or sodium thioglycolate in combination with strong alkali. Enzymatic preparations are sometimes added to improve the performance of the process. After liming in a tannery recognised as a 'technical plant' by the competent authority, the hides or skins are no longer subject to animal by-products controls.

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