U.S. patents available from 1976 to present.
U.S. patent applications available from 2005 to present.

Environment-protecting method for the liming of raw hides

Patent 4457759 Issued on July 3, 1984. Estimated Expiration Date: Icon_subject October 29, 2002. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

2157969

2179899

3574516

Soaking method Patent #: 4278432
Issued on: 07/14/1981
Inventor: Monsheimer ,   et al.

Inventors

Application

No. 06/440222 filed on 10/29/1982

US Classes:

8/94.16, Depilating8/94.17Alkaline material removal

Examiners

Primary: Tungol, Maria Parrish

Attorney, Agent or Firm

International Classes

C14C 1/06 (20060101)
C14C 1/00 (20060101)

Foreign Application Priority Data

1981-03-12 HU

Abstract

The invention relates to an environment-protecting method for the liming of raw hides, wherein, after an optional mechanical degreasing step, the hides are subjected to presoaking, chemical degreasing, washing, alkaline swelling and collapsing, enzymatic unhairing, plucking and liming, and the sulfide ions remaining in the liquor after liming are deactivated. According to the invention the raw hides are treated, prior to liming, with 0.05 to 0.50% by weight of a proteolytic enzyme with an Anson-activity of 1.2 to 1.5 in a bath of a temperature not exceeding 35° C. and a pH value not exceeding 12, thereafter the hides are subjected to hair-destruction liming with a lime liquor containing not more than 2.0% by weight of disodium sulfide and/or sodium hydrogen sulfide, calculated for the weight of the raw hide, and the sulfide ions remaining in the lime liquor are oxidized directly in the liming vessel so that 100% by weight of water and at least 0.04% by weight of manganese sulfate are added to the used lime liquor in the presence of the limed hides, the hides are rotated in the liquor for at least 15 minutes, thereafter up to 1.0% by weight of technical hydrogen peroxide are added, preferably in three portions at intervals of 10 minutes, to the liquor within an additional rotation period not exceeding 150 minutes.

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