Bleaching and dyeing; fluid treatment and chemical modification – Treatment of hides – skins – feathers and animal tissues – Depilating
Reexamination Certificate
2007-04-03
2007-04-03
McGinty, Douglas (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Treatment of hides, skins, feathers and animal tissues
Depilating
C008S094170, C008S094180
Reexamination Certificate
active
10350375
ABSTRACT:
The present invention relates to a process for lime- and sulfide-free unhairing of skins/hides using animal and/or herbal (plant) enzymes. The process comprises presoaking the skins or hides in water for 2–6 hours, pasting an enzyme solution of animal or plant origin on the flesh or grain side of the skins/hides and leaving the solution on the skins/hides for 10–24 h at a temperature ranging from 10° C. to 60° C. The soaking liquor is removed and the hides/skins to a bath of water containing 1 to 15% of enzyme for unhairing, with or without intermittent shaking, while maintaining the pH of the bath liquor at 4.5–10.0 for 12–24 h at ambient temperature. The skins/hides are then unhaired for further processing. The total elimination of lime and sulfide in the unhairing process leads to reduced TDS (total dissolved solids), BOD (biological oxygen demand) and COD (chemical oxygen demand) in the effluent without affecting the collagen of the skin/hide or the grain pattern.
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Iyappan Kuttalam
Parvathaleswara Thotapalli
Rajini Raju
Ramalingam Samayavaram
Ramasami Thirumalaichari
Baker & Botts LLP
Council of Scientific and Industrial Research
Kumar Preeti
McGinty Douglas
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