US 6,957,554 B2Granted

Dehairing and fiber opening process for complete elimination of lime and sodium sulfide

AssigneeCouncil of Scientific and Industrial Research

InventorsSubramani Saravanabhavan, Palanisamy Thanikaivelan, Jonnalagadda Raghava Rao, Balachandran Unni Nair, Thirumalachari Ramasami

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Abstract

The use of lime and sodium sulfide in leather making creates a lot of environmental concern. However, there is no commercial beam house process that could totally eliminate the use of lime and sodium sulfide. In this invention, a novel bio-chemical process has been standardized employing specific enzymes and non-toxic chemical that could totally eliminate the use of lime and sodium sulfide in leather processing. It has been found that the extent of hair removal and opening up of fiber bundles is comparable to that of the conventional limed leathers. Performance of the leathers is shown to be on par with conventionally leathers. The process also enjoys reduction in chemical oxygen demand and total solids load compared to conventional process.

Claims17

Dependent claims

A novel dehairing and fibre opening process for complete elimination of lime and sodium sulfide suitable for all kind of raw materials, comprising:

i. adding water in an amount from about 5% to about 10% w/w, with respect to the weight of soaked hides/skins, and proteolytic enzyme, exhibiting activity at a temperature from about 25° C. to about 400° C. and a pH from about 7.5 to about 11.0, optionally in the presence of silicate salt, to prepare a paste,
ii. applying the paste, as formed in step (i), on the flesh or grain side of the hides/skin,
iii. piling the pasted hides/skins, grain to grain, for a period of not less than 12 hours followed by removing the hair to get dehaired hides/skins,
iv. treating the dehaired hides/skins, as obtained in step (ii), with silicate salt in presence of water, preferably under stirring condition, for a period of not less than 3 hrs, followed by fleshing to get pelt for subsequent post fibre opening processes.

1 more element

Dependencies are inferred from the claim text.