Title of Invention	A PROCESS FOR THE PREPARATION OF AN ECOFRIENDLY BLACK COLOURANT FORM MYROBALAN SLUDGE FOR USE IN LEATHER INDUSTRY
Abstract	The present invention relates to a process for the preparation of an ecoftiendly black colourant from myrobalan sludge for use in leather industry. This ecorriendly colourant finds potential use as a black pigment for finishing of leather. This process of the present invention provides a novel method of economical use of myrobalan sludge, which would otherwise have reated disposal problem in the environment, to prepare eco-friendly black colourant for learner industry using non-toxic chemicals, suggesting a viable long term solution for the dual problem of the colourant as well as the myrobalan extract industry, ensuring generation of wealth from waste.

Title of Invention

A PROCESS FOR THE PREPARATION OF AN ECOFRIENDLY BLACK COLOURANT FORM MYROBALAN SLUDGE FOR USE IN LEATHER INDUSTRY

Abstract

The present invention relates to a process for the preparation of an ecoftiendly black colourant from myrobalan sludge for use in leather industry. This ecorriendly colourant finds potential use as a black pigment for finishing of leather. This process of the present invention provides a novel method of economical use of myrobalan sludge, which would otherwise have reated disposal problem in the environment, to prepare eco-friendly black colourant for learner industry using non-toxic chemicals, suggesting a viable long term solution for the dual problem of the colourant as well as the myrobalan extract industry, ensuring generation of wealth from waste.

Full Text	The present invention relates to a process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry. This ecofriendly colourant finds potential use as a black pigment for finishing of leather. As per definitions provided by the Society of Dyers and Colourists, Colour Terras and Definitions, revised in 1979 ( Journal of the Society of Leather Technologists & Chemists 68,123,1984), "A pigment is a substance in a particular form that is substantially insoluble in a medium but which can be mechanically dispersed in the medium to modify its colour and/or light scattering properties". Pigments are available in different forms of earth colours, prepared pigments and colour lakes. Earth colours, which are the natural pigments, exhibit good body and covering power, while the prepared pigments like chrome yellow, red lead, titan white etc. exhibit less body and covering power. Both natural and synthetic pigments are used in several industries like textiles, leather, plastics, food, pharmaceuticals, cosmetics etc. to impart aesthetic value to the finished products. The pigments available in the market usually fall under the category of prepared pigments and coloured lakes. Leather finishing requires substantial amount of pigments not only for making leathers of various appealing shades, but also for covering the defects present on the leather surface, to ensure good value addition to the finished product in the international market. Finely ground pigment is mixed with other film forming materials, plasticisers ,preservatives etc. and is suspended in water to required concentration before applying on leather surface manually or mechanically. Dye solution of similar shade is sometimes added to the season for the purpose of brightening the shade. It has been reported by R.J.Tremlett (Journal of the Society of Leather Technologists & Chemists,79,5,1995) that black colourants account for about 50% and brown colourants account for about 25% of the total consumption of colourants in leather industry, while the remaining 25% is accounted for by the other shades. Concern for eco-friendly technologies has of late become very prominent. The growing public awareness to protect the environment has persuaded all processing industries to use environmentally safe processes and ecofriendly chemicals / formulations / auxiliaries. Efforts are being made to eliminate the use of chemicals, which are toxic or hazardous. The restrictions imposed recently by the European countries like Germany, France, Netherlands etc., (Federal Law Gazette, No.36 of 1993, Bonn, FRG., and Chemical Weekly, Sevak Publications, Bombay,Vol.XLII.No.I, Sep.3, 1996,p.74) on the usage of colourants based on hazardous/carcinogenic aromatic amines in consumer goods have gone a long way to prompt the researchers to look for better and safer alternatives. As reported by M.D.Garret (Pigment Handbook, Vol.1,Properties and Economics, Ed.T.C.Patton, A Wiley Interscience Publication, New York 1973, p.709) and 0'Flaherty, Roddy & Lollar ( The Chemistry and Technology of Leather,Vol.IV,Evaluation of leather, Reinhold Publishing Corporation,1965, p.204), carbon black, lamp black and bone black have been and are being used as pigments. Carbon blacks are manufactured by thermal decomposition or incomplete combustion of hydrocarbon compounds, whereas bone black is produced by charring animal bones in the absence of air. As reported by Seymour Broad (Pigment Handbook, Vol.l,Properties and Economics, Ed.T.C.Patton. A Wiley Interscience Publication, New York, 1973, p.781.), natural pigments based on hematoxylein and iron were also used in pigment formulations. T.C.Thorstensen (Practical Leather Technology, Robert E.Krieger Publishing Company, New York,1975,p.175.) reported that logwood {Hematoxylon campechianum) pigment was the only natural black pigment used in leather industry. Logwood extract is obtained from the heart wood and continuous exploitation of this plant material for the purpose of making black pigment will ultimately result in deforestation leading to serious environmental problem. Logwood pigments are generally precipitated out of an aqueous extract of logwood using iron or chromium salts. Since chromium has been identified as toxic and hazardous substance, the existing process of preparing black pigment from natural plant source is expected to affect adversely the environment, which has of late gained prime importance, thereby suggesting a probable shortage of availability of ecofriendly natural pigments in the long run. According to J.M.Matthews (Application of dyestuffs to textiles, paper, leather and other materials, John Wiley & Sons Inc., New York, 1947, p.265), getting black colours by the combination of phenolic compounds and iron salts is a well established practice in some of the traditional textile dyeing/printing processes. Various plant materials are used, either individually or in combination of two or three along with metallic strikers, for obtaining blacks on textile materials. India being a tropical country enjoys rich flora. It boasts of various tannin bearing plants having potential commercial usage. Terminalia chebula is one such tannin bearing plant of Indian origin and its fruits are commonly known as myrobalan nuts. Myrobalan has been one of the most important tanning materials used for vegetable tannage of leather. It is commercially used, either individually or along with other tanning materials, for the manufacture of tannin extracts in the form of solid or spray dried powder. During the manufacture of myrobalan extract, large quantities of waste materials are obtained in the form of rejects, sludge and spent materials, which are currently being either utilised as boiler feed or discarded. Proper disposal of these waste materials seems to be a crying need of the hour to solve a practical problem of the vegetable tanning extract manufacturing units regarding the economical disposal of the accumulatad wastes. The main object of the present invention is to provide a process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry which obviates the drawbacks detailed above.. Another object of the present invention is to solve the solid waste disposal problems faced by the tannin extract manufacturing units. Yet another object of the present invention is to replace the toxic synthetic colorants with non-hazardous materials. Still another object of the present invention is to utilize the waste materials of the tannin extract manufacturing industry for the preparation of non-hazardous colorants, thereby generating wealth out of waste. Accordingly the present invention provides a process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry which comprises; i) purifying the myrobalan sludge by treating with 200-300% by wt. of water, ii) adjusting the solid content of the aqueous slurry of myrobalan to 10-20% by conventional methods, iii) adjusting the pH of the slurry to 6-10 by adding alkali, as herein described, iv) reacting the slurry with 10-15%(w/v) an aqueous solution of a non-toxic iron salt, as herein described, stirring for 8 to 12 hrs and allowed to settle for 2 to 8 hrs, v) drying the residual cake by conventional methods at a temperature in the range of 90-110°C, vi) Pulverizing the dried cake into an aveiage particular size of less than 5 microns, to obtain the said black colournat. In an embodiment of the present invention, the purification of toe sludge may be carried out by stirring in plain water, followed by decanting and filtering the aqueous mixture. In another embodiment of the present invention, pH of the liquor may be adjusted to 6-10 with aqueous alkali solutions like, sodium carbonate, sodium hydroxide, potassium hydroxide. In yet another embodiment of the present invention, non-toxic metallic salt could be selected from among ferric chloride, ferric ammonium sulphate and ferric alum. Sludge obtained during the vegetable tannin extraction of myrobalan is used as the raw material for this present invention. The sludge is stirred with 200-300% by weight of plain water to make it free from several impurities like sand, fibers of myrobalan nuts etc. Conventional filtration or decantation process is employed for the purification of the sludge. Solid content of the slurry is adjusted to 10-20% either by diluting or evaporating water. pH of the slurry is adjusted to 6-10 by adding aqueous alkali solution. To the above liquor, 10-50% w/v aqueous solution of a non-toxic iron salt is added with constant stirring, which is continued for 8 to 12 hrs, and the mixture is allowed to settle for 2 to 8 hrs. It is then centrifuged conventionally and the settled cake is dried by conventional methods to a temperature in the range of 90-ll0°C to get dry black pigment lumps. The dried lumps are pulverised in conventional way to a particle size of less than 5 microns. This micronised pigment is used for the purpose of leather finishing. Thus this process of the present invention provides a novel method of economical use of myrobalan sludge, which would otherwise have created disposal problem in the environment, to prepare eco-friendly black colourant for leather industry using non-toxic chemicals, suggesting a viable long term solution for the dual problem of the colourant as well as the myrobalan extract industry, ensuring generation of wealth from waste. The following exaaples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention. Example I 1000 gms of Myrobalan sludge was taken in a 5 lit beaker, and 2 lits of water was added to it with constant stirring. The mixture was allowed to settle for 15 mins. Sand and other insoluble heavy particles, settled at the bottom, were removed by decantation. Fibrous materials are removed by filtration through a coarse filter. The solid content of the slurry of the purified sludge was adjusted to 15% w/v and pH of the mixture was found to be 3. 20% w/v, Aqueous solution of sodium carbonate was added dropwise to the slurry to raise the pH to 6 and the mixture was stirred for 2 hrs. 75ml of 20% w/v, Aqueous ferric alum solution was then added to the above liquor with constant stirring for 1 hr. Stirring was continued for a further period of 8 hrs and the liquor was allowed to settle for 3 hrs. The settled pigment was centrifuged and dried at 100-110°C in a hot air oven. The dried pigment cake was pulverised in a mini ball mill to a particle size of less than 5 microns. The pigment was used in the formulation of leather finishing. Example 2 800 gms of myrobalan sludge was taken in a 5 lit beaker, 2 lits of water was added to it with constant stirring and allowed to settle for 25 mins. Sand and other insoluble heavy particles were removed by decantation. Fibrous materials were removed by filtration through a coarse filter. The solid content of the slurry of the purified sludge was adjusted to 20% w/v and pH of the mixture was found to be 2.8, which was raised to 8 by adding 30% w/v, aqueous solution of potassium hydroxide to it with constant stirring for 2 hrs. 5 0 ml of 3 0% w/v Aqueous ferric ammonium sulphate solution was then added to the above liquor with constant stirring for 2 hrs and the stirring was continued for a further period of 10 hrs. The mixture was then allowed to settle for a period of 5 hrs. The settled pigment was centrifuged and dried at 100-110°C in a hot air oven. The dried pigment was pulverised in a mini ball mill to a particle size of less than 5 microns. The pigment was used in the formulation of season for leather finishing. Example i 1500 gms of Myrobalan sludge was taken in a 5 lit beaker, 2.5 lits of water was added to it with constant stirring and allowed to settle for 30 mins. Sand and other excipient heavy particles are removed by decantation. Floating myrobalan fibre particles were removed by filtration through a coarse filter. The solid content of the slurry of the purified sludge was adjusted to 20% w/v, and the pH of the mixture was found to be 3.2, which was raised to 10 by adding 40% w/v, aqueous solution of sodium hydroxide dropwise to the mixture with continuous stirring for 1.5 hrs. 50 ml of 20% w/v, Aqueous ferric chloride solution was then added with constant stirring for 1 hr and stirring was continued for a further period of 10 hrs. The mixture was then allowed to settle for 8 hrs. The settled pigment was centrifuged and dried at 100-110°C in a hot air oven. The dried pigment was pulverised in a mini ball mill to a particle size of less than 5 microns. The pigment was used in the formulation of season for leather finishing. The main advantages of the present invention are the following. 1. Ecofriendly , natural black colourant for leather is made from large quantities of solid waste material obtained during the manufacture of myrobalan tannin extract in the form of sludge, which is currently discarded, thereby generating wealth out of waste and also minimising the solid waste disposal problems faced by the myrobalan tannin extract manufacturing units. 2. The process yields a ready-to-use colourant for leather finishing formulations. 3. This process makes use of plant product waste and non-toxic metallic salts, which are environmentally friendly. 4. The colourants prepared by this process are free from banned chemicals like arylamines. We Claim: 1. A process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry which comprises; i) purifying the myrobalan sludge by treating with 200-300% by wt. of water, ii) adjusting the solid content of the aqueous slurry of myrobalan to 10-20% by conventional methods, iii) adjusting the pH of the slurry to 6-10 by adding alkali, as herein described iv) reacting the slurry with 10-15% (w/v) of an aqueous solution of a non-toxic iron salt, as herein described, stirring for 8 to 12 hrs and allowed to settle for 2 to 8 hrs, v) drying the residual cake by conventional methods at a temperature in the rangeof90-110°C, vi) pulverizing the dried cake into an average particle size of less than 5 microns, to obtain the said black colournat. 2. A process as claimed in claim 1 wherein the alkali used is selected from sodium carbonate, sodium hydroxide and potassium hydroxide. 3. A process as claimed in claim 1 and 2, wherein the non-toxic metallic salt used is selected from ferric chloride, ferric ammonium sulphate and ferric alum. 4. A process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry substantially as herein described with reference to the examples.

Full Text

The present invention relates to a process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry. This ecofriendly colourant finds potential use as a black pigment for finishing of leather.
As per definitions provided by the Society of Dyers and Colourists, Colour Terras and Definitions, revised in 1979 ( Journal of the Society of Leather Technologists & Chemists 68,123,1984), "A pigment is a substance in a particular form that is substantially insoluble in a medium but which can be mechanically dispersed in the medium to modify its colour and/or light scattering properties".
Pigments are available in different forms of earth colours, prepared pigments and colour lakes. Earth colours, which are the natural pigments, exhibit good body and covering power, while the prepared pigments like chrome yellow, red lead, titan white etc. exhibit less body and covering power. Both natural and synthetic pigments are used in several industries like textiles, leather, plastics, food, pharmaceuticals, cosmetics etc. to impart aesthetic value to the finished products. The pigments available in the market usually fall under the category of prepared pigments and
coloured lakes.

Leather finishing requires substantial amount of pigments not only for making leathers of various appealing shades, but also for covering the defects present on the leather surface, to ensure good value addition to the finished product in the international market. Finely ground pigment is mixed with other film forming materials, plasticisers ,preservatives etc. and is suspended in water to required concentration before applying on leather surface manually or mechanically. Dye solution of similar shade is sometimes added to the season for the purpose of brightening the shade. It has been reported by R.J.Tremlett (Journal of the Society of Leather Technologists & Chemists,79,5,1995) that black colourants account for about 50% and brown colourants account for about 25% of the total consumption of colourants in leather industry, while the remaining 25% is accounted for by the other shades.
Concern for eco-friendly technologies has of late become very prominent. The growing public awareness to protect the environment has persuaded all processing industries to use environmentally safe processes and ecofriendly chemicals / formulations / auxiliaries. Efforts are being made to eliminate the use of chemicals, which are toxic or hazardous. The

restrictions imposed recently by the European countries like Germany, France, Netherlands etc., (Federal Law Gazette, No.36 of 1993, Bonn, FRG., and Chemical Weekly, Sevak Publications, Bombay,Vol.XLII.No.I, Sep.3, 1996,p.74) on the usage of colourants based on hazardous/carcinogenic aromatic amines in consumer goods have gone a long way to prompt the researchers to look for better and safer alternatives.
As reported by M.D.Garret (Pigment Handbook, Vol.1,Properties and Economics, Ed.T.C.Patton, A Wiley Interscience Publication, New York 1973, p.709) and 0'Flaherty, Roddy & Lollar ( The Chemistry and Technology of Leather,Vol.IV,Evaluation of leather, Reinhold Publishing Corporation,1965, p.204), carbon black, lamp black and bone black have been and are being used as pigments. Carbon blacks are manufactured by thermal decomposition or incomplete combustion of hydrocarbon compounds, whereas bone black is produced by charring animal bones in the absence of air.
As reported by Seymour Broad (Pigment Handbook, Vol.l,Properties and Economics, Ed.T.C.Patton. A Wiley Interscience Publication, New York, 1973, p.781.), natural pigments based on hematoxylein and iron were also used in pigment formulations. T.C.Thorstensen

(Practical Leather Technology, Robert E.Krieger Publishing Company, New York,1975,p.175.) reported that logwood {Hematoxylon campechianum) pigment was the only natural black pigment used in leather industry. Logwood extract is obtained from the heart wood and continuous exploitation of this plant material for the purpose of making black pigment will ultimately result in deforestation leading to serious environmental problem. Logwood pigments are generally precipitated out of an aqueous extract of logwood using iron or chromium salts. Since chromium has been identified as toxic and hazardous substance, the existing process of preparing black pigment from natural plant source is expected to affect adversely the environment, which has of late gained prime importance, thereby suggesting a probable shortage of availability of ecofriendly natural pigments in the long run.
According to J.M.Matthews (Application of dyestuffs to textiles, paper, leather and other materials, John Wiley & Sons Inc., New York, 1947, p.265), getting black colours by the combination of phenolic compounds and iron salts is a well established practice in some of the traditional textile dyeing/printing processes. Various plant materials are used, either individually
or in combination of two or three along with metallic strikers, for obtaining blacks on textile materials.
India being a tropical country enjoys rich flora. It boasts of various tannin bearing plants having potential commercial usage. Terminalia chebula is one such tannin bearing plant of Indian origin and its fruits are commonly known as myrobalan nuts.
Myrobalan has been one of the most important tanning materials used for vegetable tannage of leather. It is commercially used, either individually or along with other tanning materials, for the manufacture of tannin extracts in the form of solid or spray dried powder. During the manufacture of myrobalan extract, large quantities of waste materials are obtained in the form of rejects, sludge and spent materials, which are currently being either utilised as boiler feed or discarded. Proper disposal of these waste materials seems to be a crying need of the hour to solve a practical problem of the vegetable tanning extract manufacturing units regarding the economical disposal of the accumulatad wastes.
The main object of the present invention is to provide a process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather
industry which obviates the drawbacks detailed above.. Another object of the present invention is to solve the solid waste disposal problems faced by the tannin extract manufacturing units.
Yet another object of the present invention is to replace the toxic synthetic colorants with non-hazardous materials.
Still another object of the present invention is to utilize the waste materials of the tannin extract manufacturing industry for the preparation of non-hazardous colorants, thereby generating wealth out of waste.
Accordingly the present invention provides a process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry which comprises;
i) purifying the myrobalan sludge by treating with 200-300% by wt. of water,
ii) adjusting the solid content of the aqueous slurry of myrobalan to 10-20% by conventional methods,
iii) adjusting the pH of the slurry to 6-10 by adding alkali, as herein described,
iv) reacting the slurry with 10-15%(w/v) an aqueous solution of a non-toxic iron salt, as herein described, stirring for 8 to 12 hrs and allowed to settle for 2 to 8 hrs,
v) drying the residual cake by conventional methods at a temperature in the
range of 90-110°C, vi) Pulverizing the dried cake into an aveiage particular size of less than 5
microns, to obtain the said black colournat.
In an embodiment of the present invention, the purification of toe sludge may be carried out by stirring in plain water, followed by decanting and filtering the aqueous mixture.
In another embodiment of the present invention, pH of the liquor may be adjusted to 6-10 with aqueous alkali solutions like, sodium carbonate, sodium hydroxide, potassium hydroxide.
In yet another embodiment of the present invention, non-toxic metallic salt could be selected from among ferric chloride, ferric ammonium sulphate and ferric alum.
Sludge obtained during the vegetable tannin extraction of myrobalan is used as the raw material for this present invention. The sludge is stirred with 200-300% by weight of plain water to make it free from several impurities like sand, fibers of myrobalan nuts etc. Conventional filtration or decantation process is employed for the purification of the sludge. Solid content of the slurry is adjusted to 10-20% either by diluting or evaporating water. pH of the slurry is
adjusted to 6-10 by adding aqueous alkali solution.
To the above liquor, 10-50% w/v aqueous solution of a non-toxic iron salt is added with constant stirring, which is continued for 8 to 12 hrs, and the mixture is allowed to settle for 2 to 8 hrs. It is then centrifuged conventionally and the settled cake is dried by conventional methods to a temperature in the range of 90-ll0°C to get dry black pigment lumps. The dried lumps are pulverised in conventional way to a particle size of less than 5 microns. This micronised pigment is used for the purpose of leather finishing.
Thus this process of the present invention provides a novel method of economical use of myrobalan sludge, which would otherwise have created disposal problem in the environment, to prepare eco-friendly black colourant for leather industry using non-toxic chemicals, suggesting a viable long term solution for the dual problem of the colourant as well as the myrobalan extract industry, ensuring generation of wealth from waste.
The following exaaples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention.
Example I
1000 gms of Myrobalan sludge was taken in a 5 lit beaker, and 2 lits of water was added to it with constant stirring. The mixture was allowed to settle for 15 mins. Sand and other insoluble heavy particles, settled at the bottom, were removed by decantation. Fibrous materials are removed by filtration through a coarse filter. The solid content of the slurry of the purified sludge was adjusted to 15% w/v and pH of the mixture was found to be 3.
20% w/v, Aqueous solution of sodium carbonate was added dropwise to the slurry to raise the pH to 6 and the mixture was stirred for 2 hrs. 75ml of 20% w/v, Aqueous ferric alum solution was then added to the above liquor with constant stirring for 1 hr. Stirring was continued for a further period of 8 hrs and the liquor was allowed to settle for 3 hrs. The settled pigment was centrifuged and dried at 100-110°C in a hot air oven.
The dried pigment cake was pulverised in a mini ball mill to a particle size of less than 5 microns.
The pigment was used in the formulation of leather finishing.
Example 2
800 gms of myrobalan sludge was taken in a 5 lit beaker, 2 lits of water was added to it with constant stirring and allowed to settle for 25 mins. Sand and other insoluble heavy particles were removed by decantation. Fibrous materials were removed by filtration through a coarse filter. The solid content of the slurry of the purified sludge was adjusted to 20% w/v and pH of the mixture was found to be 2.8, which was raised to 8 by adding 30% w/v, aqueous solution of potassium hydroxide to it with constant stirring for 2 hrs.
5 0 ml of 3 0% w/v Aqueous ferric ammonium sulphate solution was then added to the above liquor with constant stirring for 2 hrs and the stirring was continued for a further period of 10 hrs. The mixture was then allowed to settle for a period of 5 hrs. The settled pigment was centrifuged and dried at 100-110°C in a hot air oven.
The dried pigment was pulverised in a mini ball mill to a particle size of less than 5 microns.
The pigment was used in the formulation of season for leather finishing.
Example i
1500 gms of Myrobalan sludge was taken in a 5 lit beaker, 2.5 lits of water was added to it with constant stirring and allowed to settle for 30 mins. Sand and other excipient heavy particles are removed by decantation. Floating myrobalan fibre particles were removed by filtration through a coarse filter. The solid content of the slurry of the purified sludge was adjusted to 20% w/v, and the pH of the mixture was found to be 3.2, which was raised to 10 by adding 40% w/v, aqueous solution of sodium hydroxide dropwise to the mixture with continuous stirring for 1.5 hrs.
50 ml of 20% w/v, Aqueous ferric chloride solution was then added with constant stirring for 1 hr and stirring was continued for a further period of 10 hrs. The mixture was then allowed to settle for 8 hrs. The settled pigment was centrifuged and dried at 100-110°C in a hot air oven.
The dried pigment was pulverised in a mini ball mill to a particle size of less than 5 microns.
The pigment was used in the formulation of season for leather finishing.
The main advantages of the present invention are the
following.
1. Ecofriendly , natural black colourant for leather is
made from large quantities of solid waste material
obtained during the manufacture of myrobalan tannin
extract in the form of sludge, which is currently
discarded, thereby generating wealth out of waste and
also minimising the solid waste disposal problems faced
by the myrobalan tannin extract manufacturing units.
2. The process yields a ready-to-use colourant for leather finishing formulations.
3. This process makes use of plant product waste and non-toxic metallic salts, which are environmentally friendly.
4. The colourants prepared by this process are free from banned chemicals like arylamines.

We Claim:
1. A process for the preparation of an ecofriendly black colourant from myrobalan
sludge for use in leather industry which comprises;
i) purifying the myrobalan sludge by treating with 200-300% by wt. of water, ii) adjusting the solid content of the aqueous slurry of myrobalan to 10-20% by
conventional methods, iii) adjusting the pH of the slurry to 6-10 by adding alkali, as herein described iv) reacting the slurry with 10-15% (w/v) of an aqueous solution of a non-toxic
iron salt, as herein described, stirring for 8 to 12 hrs and allowed to settle for 2
to 8 hrs, v) drying the residual cake by conventional methods at a temperature in the
rangeof90-110°C, vi) pulverizing the dried cake into an average particle size of less than 5 microns,
to obtain the said black colournat.
2. A process as claimed in claim 1 wherein the alkali used is selected from sodium carbonate, sodium hydroxide and potassium hydroxide.
3. A process as claimed in claim 1 and 2, wherein the non-toxic metallic salt used is selected from ferric chloride, ferric ammonium sulphate and ferric alum.
4. A process for the preparation of an ecofriendly black colourant from myrobalan sludge for use in leather industry substantially as herein described with reference to the examples.

Documents:

1868-del-1997-abstract.pdf

1868-del-1997-claims.pdf

1868-del-1997-complete-spacification(granted).pdf

1868-del-1997-correspondence-others.pdf

1868-del-1997-correspondence-po.pdf

1868-del-1997-description (complete).pdf

1868-del-1997-form-1.pdf

1868-del-1997-form-19.pdf

1868-del-1997-form-2.pdf

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Patent Number

232475

Indian Patent Application Number

1868/DEL/1997

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

17-Mar-2009

Date of Filing

04-Jul-1997

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG,NEW DELHI-110001,INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	DORAISWAMY MURALIDHARAN	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.
2	WUPPALAMARTHY MADHULATHA	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.
3	VAJHALA SYAMA SUNDARA RAO	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.
4	THIRUMALACHARI RAMASAMI	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.
5	NARASIMHAN KANNAN CHANDRABABU	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.
6	KRISHNASWAMY PARTHASARATHY	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.
7	KONDAPURAM VIJAYA RAGHAVAN	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.
8	GOPALAKRISHNA THYAGARAJAN	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR,CHENNAI-600 020,INDIA.

PCT International Classification Number

C09B 61/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA