US3574516A - Dehairing of hides and skins - Google Patents
Dehairing of hides and skins Download PDFInfo
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- US3574516A US3574516A US537671A US3574516DA US3574516A US 3574516 A US3574516 A US 3574516A US 537671 A US537671 A US 537671A US 3574516D A US3574516D A US 3574516DA US 3574516 A US3574516 A US 3574516A
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- United States
- Prior art keywords
- skins
- hides
- dehairing
- hair
- treated
- Prior art date
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- Expired - Lifetime
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- 238000000034 method Methods 0.000 abstract description 19
- 150000001875 compounds Chemical class 0.000 abstract description 7
- 150000007529 inorganic bases Chemical class 0.000 abstract description 7
- 239000007864 aqueous solution Substances 0.000 abstract description 6
- ROSDSFDQCJNGOL-UHFFFAOYSA-N Dimethylamine Chemical compound CNC ROSDSFDQCJNGOL-UHFFFAOYSA-N 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 239000000243 solution Substances 0.000 description 9
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 7
- 239000000920 calcium hydroxide Substances 0.000 description 7
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 7
- 150000003839 salts Chemical class 0.000 description 6
- 150000001340 alkali metals Chemical class 0.000 description 5
- 230000007935 neutral effect Effects 0.000 description 5
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 4
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 239000001110 calcium chloride Substances 0.000 description 4
- 229910001628 calcium chloride Inorganic materials 0.000 description 4
- 244000309466 calf Species 0.000 description 4
- PFUVRDFDKPNGAV-UHFFFAOYSA-N sodium peroxide Chemical compound [Na+].[Na+].[O-][O-] PFUVRDFDKPNGAV-UHFFFAOYSA-N 0.000 description 4
- 239000002351 wastewater Substances 0.000 description 4
- 241000283690 Bos taurus Species 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- -1 alkaline earth metal sulfides Chemical class 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 230000008961 swelling Effects 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 description 2
- 150000003973 alkyl amines Chemical class 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 150000007530 organic bases Chemical class 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 150000002978 peroxides Chemical class 0.000 description 2
- 231100000614 poison Toxicity 0.000 description 2
- 229960001922 sodium perborate Drugs 0.000 description 2
- YKLJGMBLPUQQOI-UHFFFAOYSA-M sodium;oxidooxy(oxo)borane Chemical compound [Na+].[O-]OB=O YKLJGMBLPUQQOI-UHFFFAOYSA-M 0.000 description 2
- 102000008186 Collagen Human genes 0.000 description 1
- 108010035532 Collagen Proteins 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910001508 alkali metal halide Inorganic materials 0.000 description 1
- 229910001615 alkaline earth metal halide Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000004061 bleaching Methods 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- QBWCMBCROVPCKQ-UHFFFAOYSA-N chlorous acid Chemical compound OCl=O QBWCMBCROVPCKQ-UHFFFAOYSA-N 0.000 description 1
- 229940077239 chlorous acid Drugs 0.000 description 1
- 229920001436 collagen Polymers 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 125000002147 dimethylamino group Chemical group [H]C([H])([H])N(*)C([H])([H])[H] 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000010985 leather Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 230000007096 poisonous effect Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- UKLNMMHNWFDKNT-UHFFFAOYSA-M sodium chlorite Chemical compound [Na+].[O-]Cl=O UKLNMMHNWFDKNT-UHFFFAOYSA-M 0.000 description 1
- 229960002218 sodium chlorite Drugs 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C1/00—Chemical treatment prior to tanning
- C14C1/06—Facilitating unhairing, e.g. by painting, by liming
Definitions
- the present invention relates to a process for dehairing skins and hides, as well as a composition for carrying out such process based on compound having an oxidizing action which not only preserves the skins and hides but also permits recovery of the hair in view of its preservation during the dehairing and in addition avoids poisonous waste water.
- the object of the invention is to provide a process and composition for use therein for dehairing hides based on compounds having an oxidizing action which avoids the aforementioned disadvantages and in addition renders it possible to recover the hair removed in the dehairing operation in such a form that they may be used for other purposes.
- the essence of the invention resides in that the skins and hides to be dehaired are treated with an aqueous solution of peroxides or active oxygen yielding compounds at a pH between 10 and 13.5 in the presence of an inorganic base and, if desired, in the presence of an organic base and/or of a neutral salt.
- suitable oxidizing agents for instance, are peroxides, such as, sodium peroxide and hydrogen peroxide, as well as sodium perborate.
- the quantity of oxidizing agent employed preferably is between about 0.5 and 5% based upon the weight of the skins or hides treated.
- Alkali metal or alkaline earth metal hydroxides can, for example, 'be used as the inorganic base.
- the quantity of the inorganic base is between about 0.5 and 5% and that of the organic base, such as a lower alkyl amine of l-S carbon atoms is between about 0.5 and 3% based upon the weight of the skins treated.
- the water soluble alkali metal or alkaline earth metal halides or sulfates can, for example, be employed as the added neutral salts.
- the quantity of the neutral salts employed is between 1.0 and 5.0% based on the weight of the skins treated.
- the hair is loosened at the root, as in dehairing with alkali metal or alkaline earth metal sulfides, and can be removed easily.
- the essential advantage of the process according to the invention therefore is that the hair is preserved as it is not dissolved during the dehairing operation and can be recovered if it already is separated from the skins in the treating drum, simply by filtration of the liquor or if this is not the case with the usual machines used in the tannery.
- the process according to the invention renders it possible to avoid the presence of sulfur ions which represent a strong poison in waste water and which cannot be avoided in most dehairing procedures which have been introduced commercially.
- a further advantage of the process according to the invention is that in addition to the hair the dehaired hides also are bleached. After tanning of the pure white dehaired skins obtained it is possible to effect a very uniform aniline dyeing. At present all means are sought after which can increase the portion of the skins which can be processed to aniline dyed leather.
- Aqueous solutions of sodium peroxide containing calcium hydroxide as well as an amine, such as, dimethyl amine or a neutral salt, such as, calcium chloride have proved particularly suited for the purposes of the invention.
- EXAMPLE 1 1000 kg. of softened cow hides were treated with 20 kg. of Na O dissolved in 1000 kg. of water and 40 kg. of calcium hydroxide as well as 5 kg. of calcium chloride in a dehairing drum with occasional movement as described in Example 1. The time required for the treatment was up to a maximum of 50% longer than that required in EX- ample 1 but the swelling as compared to that of Example 1 was reduced.
- EXAMPLE 3 1000 kg. of softened cow hides were treated with 15- 17.5 kg. of Na O dissolved in 1000 kg. of water and 30 kg. of calcium hydroxide as well as 2.5 to 5 kg. of a 30% dimethyl amine solution in a dehairing drum with occasional movement as described in Example 1. The swelling as compared to that of Example 1 was significantly reduced and the loosening of the hair substantially improved over that of Example 2.
- EXAMPLE 4 1000 kg. of softened calf skins were treated on the flesh side with a solution prepared by dissolving or suspending 2025 kg. of Na 0 40 kg. of calcium hydroxide and 5 kg. of a 30% dimethyl amine solution in kg. of water. After 16 hours the hair which was hardly attacked was removed mechanically. The skins were only slightly swollen.
- EXAMPLE 5 1000 kg. of softened calf skins were treated with kg. of Na O dissolved in 1000 kg. of water, 30 kg. of calcium hydroxide and 5 kg. of a 30% dimethyl amine solution in a drum with only occasional slow movement of the drum. After 24 hours treatment, the hair was removed with a dehairing machine.
- EXAMPLE 6 1000 kg. of softened calf skins were treated with 25- kg. of Na O dissolved in 1000 kg. of water, 50 kg. of calcium hydroxide and 5 kg. of calcium chloride in a drum with only occasional slow movement of the drum as in Example 5. While the swelling was significantly reduced over that of Example 5, the loosening of the hair was sufiicient that it could easily be removed mechanically.
- EXAMPLE 7 1000 kg. of softened calf skins were treated with 25 kg. of Na O dissolved in 5000-10,000 kg. of water, 50 kg. of calcium hydroxide and 5 kg. of a 30% dimethyl amine solution as described in Example 5. This embodiment of the process permits an optimal protection of the skins against mechanical influences.
- EXAMPLE 8 100 kg. of softened and defleshed cow hides were treated with a solution of 2-3 kg. of NaOH, 2-4 kg. of H 0 by weight) and 2-5 kg. of sodium sulfate in 50 to 200 kg. of water in a drum. The hair was completely removed after 10-15 hours treatment.
- EXAMPLE 9 ganic per compound selected from the group consiting of sodium peroxide, sodium perborate and hydrogen peroxide in an amount of 0.5 to 5% based upon the weight of the skins and hides and containing an inorganic base selected from the group consiting of alkali metal and alkaline earth metal hydroxides of a pH of about 10 to 13.5 until the hair is sufiiciently loosened to permit its mechanical removal from the skins and hides.
- an inorganic base selected from the group consiting of alkali metal and alkaline earth metal hydroxides of a pH of about 10 to 13.5 until the hair is sufiiciently loosened to permit its mechanical removal from the skins and hides.
- aqueous solution also contains 1 to 5% of a salt selected from the group consisting of neutral water soluble alkali metal and alkaline earth metal sulfates and chlorides.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Detergent Compositions (AREA)
Abstract
A METHOD OF DEHAIRING SKINS AND HIDES CONSISTING OF TREATING THE SKINS AND HIDES WITH AN AQUEOUS SOLUTION CONTAINING AN INORGANIC PER COMPOUND AND AN INORGANIC BASE AT A PH OF ABOUT 10 TO 13.5 UNTIL THE HAIR IS SUFFICIENTLY LOOSENED TO PERMIT ITS MECHANICAL REMOVAL FROM THE SKINS AND HIDES.
Description
United States Patent 3,574,516 DEHAIRING 0F HIDES AND SKINS Eckhart Heidemann, Darmstadt, and Fritz Hahn, Frankfurt am Main, Germany, assignors to Deutsche Goldund Silber-Scheideanstalt vormals Roessler No Drawing. Filed Mar. 28, 1966, Ser. No. 537,671 Int. Cl. C14c 1/06 US. Cl. 8-94.16 7 Claims ABSTRACT OF THE DISCLOSURE A method of dehairing skins and hides consisting of treating the skins and hides with an aqueous solution containing an inorganic per compound and an inorganic base at a pH of about 10 to 13.5 until the hair is sufficiently loosened to permit its mechanical removal from the skins and hides.
The present invention relates to a process for dehairing skins and hides, as well as a composition for carrying out such process based on compound having an oxidizing action which not only preserves the skins and hides but also permits recovery of the hair in view of its preservation during the dehairing and in addition avoids poisonous waste water.
Recently acid solutions of sodium chlorite have been suggested for dehairing hides and skins. Chlorous acid and C10 are produced in such solutions. The dehairing with such solutions proceeds in such a manner that the hair was always destroyed starting from the hair tip so that the decomposition products thereof are present in the waste water as they are dissolved to such an extent that they cannot be filtered off. The resulting albumen content in the waste water cannot at the present time be toler ated by the industry and can only be decreased with great difiiculty. In addition, the industry has found that the oxidative attack on the collagen of the dehaired hide resulting from the process is a substantial disadvantage as it engenders a considerable reduction in tear strength of leathers produced therefrom.
The object of the invention is to provide a process and composition for use therein for dehairing hides based on compounds having an oxidizing action which avoids the aforementioned disadvantages and in addition renders it possible to recover the hair removed in the dehairing operation in such a form that they may be used for other purposes.
The essence of the invention resides in that the skins and hides to be dehaired are treated with an aqueous solution of peroxides or active oxygen yielding compounds at a pH between 10 and 13.5 in the presence of an inorganic base and, if desired, in the presence of an organic base and/or of a neutral salt. Examples of suitable oxidizing agents, for instance, are peroxides, such as, sodium peroxide and hydrogen peroxide, as well as sodium perborate. The quantity of oxidizing agent employed preferably is between about 0.5 and 5% based upon the weight of the skins or hides treated. Alkali metal or alkaline earth metal hydroxides can, for example, 'be used as the inorganic base. Preferably, the quantity of the inorganic base is between about 0.5 and 5% and that of the organic base, such as a lower alkyl amine of l-S carbon atoms is between about 0.5 and 3% based upon the weight of the skins treated. The water soluble alkali metal or alkaline earth metal halides or sulfates can, for example, be employed as the added neutral salts. Preferably, the quantity of the neutral salts employed is between 1.0 and 5.0% based on the weight of the skins treated.
In the process according to the invention, the hair is loosened at the root, as in dehairing with alkali metal or alkaline earth metal sulfides, and can be removed easily.
ice
The hair itself undergoes very little attack. A bleaching effect is achieved on the hair which is of advantage in the further processing of the hair. The essential advantage of the process according to the invention therefore is that the hair is preserved as it is not dissolved during the dehairing operation and can be recovered if it already is separated from the skins in the treating drum, simply by filtration of the liquor or if this is not the case with the usual machines used in the tannery. In addition, the process according to the invention renders it possible to avoid the presence of sulfur ions which represent a strong poison in waste water and which cannot be avoided in most dehairing procedures which have been introduced commercially.
A further advantage of the process according to the invention is that in addition to the hair the dehaired hides also are bleached. After tanning of the pure white dehaired skins obtained it is possible to effect a very uniform aniline dyeing. At present all means are sought after which can increase the portion of the skins which can be processed to aniline dyed leather.
In comparison with the prior processes, only short times are required to effect loosening of the hair whereby loss of skin substance with reduction of tearing strength and other consequences engendered thereby are reduced substantially or avoided.
Aqueous solutions of sodium peroxide containing calcium hydroxide as well as an amine, such as, dimethyl amine or a neutral salt, such as, calcium chloride have proved particularly suited for the purposes of the invention.
The following examples will serve to illustrate the invention with reference to several embodiments thereof.
EXAMPLE 1 EXAMPLE 2 1000 kg. of softened cow hides were treated with 20 kg. of Na O dissolved in 1000 kg. of water and 40 kg. of calcium hydroxide as well as 5 kg. of calcium chloride in a dehairing drum with occasional movement as described in Example 1. The time required for the treatment was up to a maximum of 50% longer than that required in EX- ample 1 but the swelling as compared to that of Example 1 was reduced.
EXAMPLE 3 1000 kg. of softened cow hides were treated with 15- 17.5 kg. of Na O dissolved in 1000 kg. of water and 30 kg. of calcium hydroxide as well as 2.5 to 5 kg. of a 30% dimethyl amine solution in a dehairing drum with occasional movement as described in Example 1. The swelling as compared to that of Example 1 was significantly reduced and the loosening of the hair substantially improved over that of Example 2.
EXAMPLE 4 1000 kg. of softened calf skins were treated on the flesh side with a solution prepared by dissolving or suspending 2025 kg. of Na 0 40 kg. of calcium hydroxide and 5 kg. of a 30% dimethyl amine solution in kg. of water. After 16 hours the hair which was hardly attacked was removed mechanically. The skins were only slightly swollen.
3 EXAMPLE 5 1000 kg. of softened calf skins were treated with kg. of Na O dissolved in 1000 kg. of water, 30 kg. of calcium hydroxide and 5 kg. of a 30% dimethyl amine solution in a drum with only occasional slow movement of the drum. After 24 hours treatment, the hair was removed with a dehairing machine.
EXAMPLE 6 1000 kg. of softened calf skins were treated with 25- kg. of Na O dissolved in 1000 kg. of water, 50 kg. of calcium hydroxide and 5 kg. of calcium chloride in a drum with only occasional slow movement of the drum as in Example 5. While the swelling was significantly reduced over that of Example 5, the loosening of the hair was sufiicient that it could easily be removed mechanically.
EXAMPLE 7 1000 kg. of softened calf skins were treated with 25 kg. of Na O dissolved in 5000-10,000 kg. of water, 50 kg. of calcium hydroxide and 5 kg. of a 30% dimethyl amine solution as described in Example 5. This embodiment of the process permits an optimal protection of the skins against mechanical influences.
EXAMPLE 8 100 kg. of softened and defleshed cow hides were treated with a solution of 2-3 kg. of NaOH, 2-4 kg. of H 0 by weight) and 2-5 kg. of sodium sulfate in 50 to 200 kg. of water in a drum. The hair was completely removed after 10-15 hours treatment.
EXAMPLE 9 ganic per compound selected from the group consiting of sodium peroxide, sodium perborate and hydrogen peroxide in an amount of 0.5 to 5% based upon the weight of the skins and hides and containing an inorganic base selected from the group consiting of alkali metal and alkaline earth metal hydroxides of a pH of about 10 to 13.5 until the hair is sufiiciently loosened to permit its mechanical removal from the skins and hides.
2. The method of claim 1 in which the quantity of said inorganic base is 0.5 to 5% based upon the weight of the skins and hides.
3. The method of claim 2 in which said aqueous solution also contains 0.5 to 3% of a lower slkyl amine of 1-5 carbon atoms based upon the weight of the skins and hides.
4. The process of claim 3 in which said lower alkyl amine is dimethyl amine.
5. The process of claim 4 in which said per compound is sodium peroxide.
6. The method of claim 2 in which said aqueous solution also contains 1 to 5% of a salt selected from the group consisting of neutral water soluble alkali metal and alkaline earth metal sulfates and chlorides.
7. The method of claim 6 in which said salt is calcium chloride.
References Cited UNITED STATES PATENTS 2,353,878 8/1944 Christopher 894.16
FOREIGN PATENTS 451,115 1935 Great Britain 8--111X 1,362,720 1964 France 8-94.16X
OTHER REFERENCES Wool-Its Chemistry and Physics, Alexander and Hudson, 1954, pp. 260-64.
LEON D. ROSDOL, Primary Examiner M. HALPERN, Assistant Examiner U.S. Cl. X.R. 8-94.15
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 3.574 .516 Dated April 13, 1971 lnventofls) Eckhart Heidemann et a1.
It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
In the heading to the printed specification, after line insert Claims priority, application Germany, March 26, 196
Signed and sealed this 23rd day of May 1972.
(SEAL) Attest:
EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US53767166A | 1966-03-28 | 1966-03-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3574516A true US3574516A (en) | 1971-04-13 |
Family
ID=24143623
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US537671A Expired - Lifetime US3574516A (en) | 1966-03-28 | 1966-03-28 | Dehairing of hides and skins |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US3574516A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4457759A (en) * | 1981-03-12 | 1984-07-03 | Bor- Mubor- Es Cipoipari Kutato Intezet | Environment-protecting method for the liming of raw hides |
| EP0519399A2 (en) * | 1991-06-19 | 1992-12-23 | Peroxidos Do Brasil Ltda. | Process for the depilation of animal skins |
| WO1996002624A1 (en) * | 1994-07-13 | 1996-02-01 | So-Safe Specialty Products Pty. Ltd. | A cleaning kit and a cleaning composition and methods of use |
| US5833718A (en) * | 1996-06-13 | 1998-11-10 | Ppg Industries, Inc. | Sodium potassium sulfide composition and method for preparing same |
| US7013838B2 (en) * | 2002-12-20 | 2006-03-21 | Frank Jay Hague | Bleached expanded pigskin and products |
-
1966
- 1966-03-28 US US537671A patent/US3574516A/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4457759A (en) * | 1981-03-12 | 1984-07-03 | Bor- Mubor- Es Cipoipari Kutato Intezet | Environment-protecting method for the liming of raw hides |
| EP0519399A2 (en) * | 1991-06-19 | 1992-12-23 | Peroxidos Do Brasil Ltda. | Process for the depilation of animal skins |
| EP0519399A3 (en) * | 1991-06-19 | 1993-03-10 | Peroxidos Do Brasil Ltda. | Process for the depilation of animal skins |
| WO1996002624A1 (en) * | 1994-07-13 | 1996-02-01 | So-Safe Specialty Products Pty. Ltd. | A cleaning kit and a cleaning composition and methods of use |
| US5833718A (en) * | 1996-06-13 | 1998-11-10 | Ppg Industries, Inc. | Sodium potassium sulfide composition and method for preparing same |
| US7013838B2 (en) * | 2002-12-20 | 2006-03-21 | Frank Jay Hague | Bleached expanded pigskin and products |
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