Title of Invention	"PROCESS FOR THE EXTRACTION OF THE YELLOW COLOURING PRINCIPLE OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L ) AND METHOD FOR THE DYEING OF TEXTILE SUBSTRATES THEREWITH"
Abstract	The present invention relates to a process for the extraction of the yellow colouring principle inherent in the seeds of the plant fenugreek (Trigonella foenum-graecum L) by subjecting such seeds to treatment with a solution of one or.more acids at a temperature in the range of from 25°C. to 100°C. for a predetermined period of time followed by solubilisation with one or a mixture of alkalis of the acid-treated seeds and extraction and recovery of the desired yellow colouring principle. The invention also includes a method for the dyeing of textile substrates with the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) so extracted. The textiles capable of being so dyed include cotton, viscose rayon and the like.

Title of Invention

"PROCESS FOR THE EXTRACTION OF THE YELLOW COLOURING PRINCIPLE OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L ) AND METHOD FOR THE DYEING OF TEXTILE SUBSTRATES THEREWITH"

Abstract

The present invention relates to a process for the extraction of the yellow colouring principle inherent in the seeds of the plant fenugreek (Trigonella foenum-graecum L) by subjecting such seeds to treatment with a solution of one or.more acids at a temperature in the range of from 25°C. to 100°C. for a predetermined period of time followed by solubilisation with one or a mixture of alkalis of the acid-treated seeds and extraction and recovery of the desired yellow colouring principle. The invention also includes a method for the dyeing of textile substrates with the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) so extracted. The textiles capable of being so dyed include cotton, viscose rayon and the like.

Full Text	The present invention relates to a process for the extraction of the bright yellow colouring principle inherent in the seeds of fenugreek (Trigonella foenum-graecum L) and to the dyeing of texile substrates therewith. In the description and claims which follow, the terms "colourant", "colouring matter" and "dye" are employed interchangeably to express or denote the same substance. Research conducted in recent times has established that that many synthetic dyes based on azo chromophore are intrinsically carcinogenic in nature and effect. For this reason, there has for some time been a growing demand for the creation of dyes which are both user- and environment-friendly. In such a situation, the vegetable world suggests itself as an obvious source to investigate and draw from in order to obtain dyes which are innocuous to humans, animals and the environment. As a result, there is now a large number of vegetable or vegetable-based dyes already in use for the dyeing of textile substrates. Unfortunately, there are numerous shortcomings encountered when attempting to extract dyes or colourants from vegetal sources. Primarily, the range or gamut of colours obtainable from such sources is extremely limited. A second drawback resides in the inability to obtain dyes of vegetal origin possessing good or even adequate colour fastness properties. These shortcomings and drawbacks have been particularly in evidence in attempts to obtain bright yellow dyes or colourants. In view of these shortcomings existent in the prior art, it will be clear that there is a need for the provision of dyes or colourants of vegetable origin, particularly bright yellow dyes and colourants, which possess good colour fastness characteristics. Earlier efforts and research have established that there is a number of vegetable sources from which yellow colouring matter suitable for the dyeing of textile substrates can be extracted. Examples of the vegetal sources which have been so' employed for this purpose include French marigold, jackfruit, flame of forest, black oak, dyer's chamomile, dyer's greenweed, safflower, weld, kamala, kaiphal, onion skin, hemp, yellow larkspur, saffron, harsinghar flowers, Indian mahogany/ annato seeds, turmeric, berberry, dolu and henna. The intrinsic colouring principle of these sources is based on the presence therein of several different types of chemical components such as flavonoids, carotenoids, diaroylmethanes, alkaloids, and quinones. The procedure which has hitherto conventionally been adopted for the extraction of the yellow colouring principle from vegetable sources has involved immersing the vegetal source in water having a pH of from 3 to 14 at a temperature in the range of from 25°C. to 100°C. for a period of time of from 1 to 24 hours. The aqueous extract of the colourant thus obtained can be used per se to dye textile material which is immersed therein. Alternatively, the aqueous extract is first filtered or filtered and dried prior to being employed as the medium for dyeing the textile material. In order to improve the wash and light fastness of the dyed material, it'has been considered advisable to pre-treat the textile material with one or more mordants prior to dyeing it. Alternatively, the material may first of all be treated with a mordant before being dyed. Yet another alternative followed is to mordant and dye the textile material simultaneously. In some instances, it has been preferred to effect a post-dyeing treatment with mordant to get the final colour. Examples of the mordants which may be employed for these purposes include tannic acid, tannins and metal salts of metals selected from iron, copper, chromium, tin, calcium, aluminium and like. These salts may be selected from the sulphates, hydroxides, halides, specifically chlorides, and complex salts of any thereof. In an endeavour to obtain a bright yellow dye which affords improved results in the dyeing of textiles such as cotton, viscose rayon, wool, silk and synthetics such as nylon, the applicants have experimented with a great number of vegetal sources. One of these sources investigated is the plant fenugreek (Trigonella foenum-graecum L.), essentially the seeds of this plant. The incentive for such investigation has been the knowledge that fenugreek seeds contain the following constituents: Volatile oil containing 3-hydroxy-4,5-dimethyl-2-furanone, dihydroxy-benzofuran, dihydroactinidiolide, murolene, elemene and selemene; Alkaloids such as trigoneline, gentianine and carpaine; Saponins based mainly on sapogenins.diosgenin and its isomer yarnogenin, gitogenin and tigogenin; Flavonoids including vitexin and its glycosides and esters, isovitexin, orientin, vicenins 1 and 2, quercetin and luteolin; and Mucilage composed essentially of galactomannan. Of the constituents mentioned, flavonoids are known to be yellow in colour. Indeed, many flavonoids such as those to be found in Reseda luteola (luteolin), Arthraxon hispidus (luteolin, arthraxin), Miscanthus tinctorius (luteolin, arthraxin), Butea monosperma (butin, butein), Mallotus philippinensis (rottlerin), and Allium cepa (quercetol) have already been employed for the dyeing of textile materials and, in particular, the colouring principle extracted from Reseda luteola, Arthraxon hispidus and Miscanthus tinctorius has been observed to evince better light fastness when compared with colouring principles extracted from other vegetable sources. It is, therefore, a primary object of the present invention to provide a process for the extraction of the yellow colouring principle of fenugreek seeds. A more specific object is the provision of a method for the dyeing of textile materials such as cotton, viscose rayon, wool, silk and nylon with the yellow colouring principle extracted from fenugreek seeds. A further object of the invention is a method for the dyeing of textile materials such as cotton, viscose rayon, wool, silk and nylon which involves the fixing of the yellow colouring principle of fenugreek seeds thereon. Accordingly, the present invention provides a process for the extraction of the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) which comprises treating fenugreek seeds with one or more acids or a source capable of yielding acid, adding to the mixture of seeds and acid a pre-determined amount of an alkali or mixture of alkalis in order to solubilise the acid-treated seeds, removing in any known manner any insoluble residue from the mixture to leave a clear solution of fenugreek extract containing the desired yellow colouring principle and, where desired, subjecting said solution to drying and recovering in any known manner said yellow colouring principle in powder form. To facilitate their treatment with the acid, the fenugreek seeds are preferably employed in comminuted or powdered form. The preferred acid employed for treatment of the fenugreek seeds is nitric acid. Where two or more acids are employed for the treatment of the seeds, the acids may be added to the seeds sequentially or simultaneously with adjustment of the temperature of the reaction accordingly. Preferably, the acid treatment of the fenugreek seeds is effected at a temperature of from 25° C. to 100°C for a period of from 10 minutes to 2 hours or even more. For facilitating the reaction procedure, water may be added to the mixture of acid and seeds. Where water is employed, the acid content may be provided or augmented by a compound or salt which yields the desired acid on contact with the added water. An example of such compound is ammonium sulphate. According to a further feature of the invention, the aqueous mixture of acid and fenugreek seeds is boiled at a temperature of approximately 60° C. to 80° C. for a period of about 1 to 2 hours. The employment of this preferred boiling step is dependent on a number of factors such as the particular acid or acid yielding compound employed, the ratio of such acid to the seeds, the treatment time and the temperature of the treatment step. A particularly preferred boiling temperature is 70°C. for a period of about 2 hours. Examples of the alkalis which may be employed in order to solubilise the acid-treated seeds include sodium hydroxide (caustic soda), sodium carbonate and potassium hydroxide. The preferred alkali is sodium hydroxide. Preferably, the mixture of acid and seeds, either prior or subsequent to the, addition of alkali thereto, is subjected to filtration and/or centrifugation in either order and then allowed to stand for a period of from 10 to 60 minutes at a temperature of from 30° C. to 40° C. Thereafter, the step of removing insoluble residue from the mixture can be effected in a manner known per se such as by decantation, centrifugation and/or filtration This results in a clear solution of the fenugreek extract containing the yellow colouring principle of fenugreek. This resulting solution of fenugreek extract containing the yellow colouring principle may be employed directly for the dyeing of textile substrates. Alternatively, the solution can be dried in air or in a vacuum drier. This presents the commercial advantage that the dried material in powder form lends itself to be' capable of storage to be employed subsequently for the re-creation of a dyeing solution. The dried material may be utilized for this purpose either per se or preferably after subjection to additional particle size reduction to below approximately 200 mesh. Where the resulting solution of fenugreek extract is not dried, it can be treated in any known manner to separate the yellow colouring principle therefrom. This separation can conveniently be effected by salting out the colouring principle for instance with sodium chloride or by precipitating it with appropriate modification of the pH of the solution. The separated colouring matter can then be dried in air or in a vacuum drier as described above and, where necessary, subjected to particle size reduction to below approximately 200 mesh. According to a further embodiment of the invention, there is provided a method for the dyeing yellow of textile substrates which comprises applying to the chosen substrate an aqueous dyeing solution of the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) extracted by the process herein described and boiling the aqueous solution containing the textile substrate for a pre-determined period of time while maintaining the pH thereof approximately neutral or moderately acidic. Preferably, the step of boiling the aqueous solution containing the textile substrate being dyed is carried out at a temperature of 80° C. to 100° C. for a period of from 30 to 60 minutes. The aqueous dyeing solution employed by the method of the invention may comprise the clear solution of fenugreek extract containing the desired yellow colouring principle resulting from the process described herein following the treatment with alkali and the step of removal of any insoluble residue. Alternatively, the aqueous dyeing solution can comprise a dispersion in water of the dried yellow colouring principle obtained after drying the clear solution of fenugreek extract resulting from the process described herein. The textiles capable of being so dyed include cotton, viscose rayon and the like. According to a preferred feature, the textile material to be dyed is pre-treated prior to dyeing with one or more auxiliary chemicals or mordants of synthetic or natural origin or with a mixture of mordants of both synthetic and natural origin. Alternatively, the material may be mordanted and dyed simultaneously. Any number of mordants may be employed for this purpose. Examples thereof include tannic acid, tannins and metal salts of metals selected from iron, copper, chromium, tin, calcium, aluminium and like. Preferred salts of these metals are the sulphates, hydroxides, halides, specifically chlorides, and complex salts of any thereof. Where desired, the method may- include a post-dyeing treatment of the textile substrate or substrates with a mordant to fix the final colour. For this purpose, the preferred mordant employed is a soluble salt of a metal selected from copper, sodium and phosphorus with the adjustment of the pH of the dyeing solution to the range of 9 to 10. In respect of cotton textiles, yarns or fibres, the method of the invention imparts a yellow colouration to the dyed textile material which possesses a light fastness of 3 and above as tested by AATCC testing method. The invention will be described in detail in the following non-limitative Examples. Example 1 EXTRACTION OF THE YELLOW COLOURING PRINCIPLE INHERENT IN THE SEEDS OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L) 100 g. of crushed fenugreek seeds were placed in an appropriate container. Next, 30 ml. of nitric acid were added to the crushed seeds with thorough stirring. The stirred mixture of acid and seeds was allowed to stand for 10 minutes whereafter 500 ml. of water were added thereto. The aqueous mixture was boiled for 60 minutes and the pH adjusted to between 10 and 11. The boiled solution was' filtered to remove any insoluble residue and leave a clear solution of fenugreek extract containing the yellow colouring principle thereof. The resulting solution was dried under vacuum to provide the desired yellow colouring principle of fenugreek (Trigonella foenum-graecum L). Example 2 DYEING OF COTTON YARN WITH THE YELLOW COLOURING PRINCIPLE OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L) Into 500 ml. of the boiled and filtered dye solution of Example 1, there were immersed 100 g. cotton yarn. The cotton yarn was maintained in the dyeing solution for 60 minutes at 80°C. during which period 2% copper sulphate and 7% trisodium phosphate were added so as to adjust the pH of the solution to 9. The resulting dyed cotton yarn exhibited a bright lemon yellow colour having a light fastness of 3 and above when measured on a light fastness tester having a xenon arc lamp simulating the sun. The invention will now be defined in the claims which follow and which must not be interpreted as limitative of the scope thereof. WE CLAIM: 1. A process for the extraction of the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) which comprises treating fenugreek seeds with one or more acids or a source capable of yielding acid such as herein described adding to the mixture of seeds and acid a pre-determined amount of an alkali or mixture of alkalis in order to solubilise the acid-treated seeds, removing in any known manner any insoluble residue from the mixture to leave a clear solution of fenugreek extract containing the desired yellow colouring principle and, where desired, subjecting said solution to drying and recovering in any known manner said yellow colouring principle in powder form. 2. A process as claimed in claim 1 wherein the treatment of the fenugreek seeds is effected with a mixture of two or more acids added to the seeds either simultaneously or sequentially with adjustment of the temperature of the reaction accordingly. 3. A process as claimed in claim 1 or 2 wherein the acid treatment of said seeds is effected at a temperature of from 25° C to 100° C for a period of from 10 minutes to 2 hours. 4. A process as claimed in any of claims 1 to 3 wherein the mixture of acid and seeds is diluted with water and the acid content is provided or augmented by a compound or salt which yields the desired acid on contact with the added water. 5. A process as claimed in claim 4 wherein the aqueous mixture of acid and fenugreek seeds is boiled at a temperature from 60 ° C to 80 ° C for a period of about 1 to 2 hours. 6. A process as claimed in claim 5 wherein said aqueous mixture of acid and fenugreek seeds is boiled at a temperature of approximately 70°C for a period of about 2 hours. 7. A process as claimed in any of claims 1 to 6 wherein the alkali employed to solubilise the acid treated seeds is selected from sodium hydroxide (caustic soda), sodium carbonate and potassium hydroxide. 8. A process as claimed in any of claims 1 to 7 wherein said fenugreek seeds are in comminuted or powdered form. 9. A process as claimed in any of claims 1 to 8 wherein the treated mixture of acid and fenugreek seeds either prior or subsequent to the addition of alkali thereto is subjected to filtration and/or centrifugation in either order before being allowed to stand and cool. 10. A process as claimed in claim 9 wherein any remaining insoluble residue is removed from the cooled mixture in a manner known per se to yield said clear solution of the fenugreek extract containing the yellow colouring principle of fenugreek. 11. A process as claimed in any of claims 1 to 10 wherein said clear solution of the fenugreek extract is subjected to drying in air or under vacuum to produce said yellow colouring principle of fenugreek in powder form. 12. A process as claimed in any of claims 1 to 10 wherein said clear solution of fenugreek extract containing the yellow colouring principle of fenugreek is treated in any known manner to separate out said colouring principle from said solution, e.g. by salting out said colouring principle with sodium chloride or by precipitating it with appropriate modification of the pH of the solution, and the separated colouring principle is recovered in a known manner and dried in air or under vacuum colouring principle is recovered in a known manner and dried in air or under. 13. A process as claimed in claim 11 or 12 wherein the dried yellow colouring principle is subjected to additional particle size reduction to below approximately 200 mesh. 14. A process for the extraction of the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) substantially as herein described with reference to foregoing Example 1. 15. Textile substrates whenever dyed by yellow colouring principle of fenugreek (Trigonella foenum-graecum L) extracted by the process claimed in any of claims 1 to 14.

Full Text

The present invention relates to a process for the extraction of the bright yellow colouring principle inherent in the seeds of fenugreek (Trigonella foenum-graecum L) and to the dyeing of texile substrates therewith. In the description and claims which follow, the terms "colourant", "colouring matter" and "dye" are employed interchangeably to express or denote the same substance.
Research conducted in recent times has established that that many synthetic dyes based on azo chromophore are intrinsically carcinogenic in nature and effect. For this reason, there has for some time been a growing demand for the creation of dyes which are both user- and environment-friendly. In such a situation, the vegetable world suggests itself as an obvious source to investigate and draw from in order to obtain dyes which are innocuous to humans, animals and the environment. As a result, there is now a large number of vegetable or vegetable-based dyes already in use for the dyeing of textile substrates.
Unfortunately, there are numerous shortcomings encountered when attempting to extract dyes or colourants from vegetal sources. Primarily, the range or gamut of colours obtainable from such sources is extremely limited. A second drawback resides in the inability to obtain dyes of vegetal origin possessing good or even adequate colour fastness properties. These shortcomings and drawbacks have been particularly in evidence in attempts to obtain bright yellow dyes or colourants.
In view of these shortcomings existent in the prior art, it will be clear that there is a need for the provision of dyes or colourants of vegetable origin, particularly bright yellow dyes and colourants, which possess good colour fastness characteristics.
Earlier efforts and research have established that there is a number of vegetable sources from which yellow colouring matter suitable for the dyeing of textile substrates can be extracted. Examples of the vegetal sources which have been so' employed for this purpose include French marigold, jackfruit, flame of forest, black oak, dyer's chamomile, dyer's greenweed, safflower, weld, kamala, kaiphal,
onion skin, hemp, yellow larkspur, saffron, harsinghar flowers, Indian mahogany/ annato seeds, turmeric, berberry, dolu and henna.
The intrinsic colouring principle of these sources is based on the presence therein of several different types of chemical components such as flavonoids, carotenoids, diaroylmethanes, alkaloids, and quinones.
The procedure which has hitherto conventionally been adopted for the extraction of the yellow colouring principle from vegetable sources has involved immersing the vegetal source in water having a pH of from 3 to 14 at a temperature in the range of from 25°C. to 100°C. for a period of time of from 1 to 24 hours. The aqueous extract of the colourant thus obtained can be used per se to dye textile material which is immersed therein. Alternatively, the aqueous extract is first filtered or filtered and dried prior to being employed as the medium for dyeing the textile material.
In order to improve the wash and light fastness of the dyed material, it'has been considered advisable to pre-treat the textile material with one or more mordants prior to dyeing it. Alternatively, the material may first of all be treated with a mordant before being dyed. Yet another alternative followed is to mordant and dye the textile material simultaneously. In some instances, it has been preferred to effect a post-dyeing treatment with mordant to get the final colour.
Examples of the mordants which may be employed for these purposes include tannic acid, tannins and metal salts of metals selected from iron, copper, chromium, tin, calcium, aluminium and like. These salts may be selected from the sulphates, hydroxides, halides, specifically chlorides, and complex salts of any thereof.
In an endeavour to obtain a bright yellow dye which affords improved results in the dyeing of textiles such as cotton, viscose rayon, wool, silk and synthetics such as nylon, the applicants have experimented with a great number of vegetal
sources. One of these sources investigated is the plant fenugreek (Trigonella foenum-graecum L.), essentially the seeds of this plant. The incentive for such investigation has been the knowledge that fenugreek seeds contain the following constituents:
Volatile oil containing 3-hydroxy-4,5-dimethyl-2-furanone, dihydroxy-benzofuran, dihydroactinidiolide, murolene, elemene and selemene;
Alkaloids such as trigoneline, gentianine and carpaine;
Saponins based mainly on sapogenins.diosgenin and its isomer yarnogenin, gitogenin and tigogenin;
Flavonoids including vitexin and its glycosides and esters, isovitexin, orientin, vicenins 1 and 2, quercetin and luteolin; and
Mucilage composed essentially of galactomannan.
Of the constituents mentioned, flavonoids are known to be yellow in colour. Indeed, many flavonoids such as those to be found in Reseda luteola (luteolin), Arthraxon hispidus (luteolin, arthraxin), Miscanthus tinctorius (luteolin, arthraxin), Butea monosperma (butin, butein), Mallotus philippinensis (rottlerin), and Allium cepa (quercetol) have already been employed for the dyeing of textile materials and, in particular, the colouring principle extracted from Reseda luteola, Arthraxon hispidus and Miscanthus tinctorius has been observed to evince better light fastness when compared with colouring principles extracted from other vegetable sources.
It is, therefore, a primary object of the present invention to provide a process for the extraction of the yellow colouring principle of fenugreek seeds.
A more specific object is the provision of a method for the dyeing of textile materials such as cotton, viscose rayon, wool, silk and nylon with the yellow colouring principle extracted from fenugreek seeds.
A further object of the invention is a method for the dyeing of textile materials such as cotton, viscose rayon, wool, silk and nylon which involves the fixing of the yellow colouring principle of fenugreek seeds thereon.
Accordingly, the present invention provides a process for the extraction of the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) which comprises treating fenugreek seeds with one or more acids or a source capable of yielding acid, adding to the mixture of seeds and acid a pre-determined amount of an alkali or mixture of alkalis in order to solubilise the acid-treated seeds, removing in any known manner any insoluble residue from the mixture to leave a clear solution of fenugreek extract containing the desired yellow colouring principle and, where desired, subjecting said solution to drying and recovering in any known manner said yellow colouring principle in powder form.
To facilitate their treatment with the acid, the fenugreek seeds are preferably employed in comminuted or powdered form.
The preferred acid employed for treatment of the fenugreek seeds is nitric acid. Where two or more acids are employed for the treatment of the seeds, the acids may be added to the seeds sequentially or simultaneously with adjustment of the temperature of the reaction accordingly.
Preferably, the acid treatment of the fenugreek seeds is effected at a temperature of from 25° C. to 100°C for a period of from 10 minutes to 2 hours or even more.
For facilitating the reaction procedure, water may be added to the mixture of acid and seeds. Where water is employed, the acid content may be provided or augmented by a compound or salt which yields the desired acid on contact with the added water. An example of such compound is ammonium sulphate.
According to a further feature of the invention, the aqueous mixture of acid and fenugreek seeds is boiled at a temperature of approximately 60° C. to 80° C. for a
period of about 1 to 2 hours. The employment of this preferred boiling step is dependent on a number of factors such as the particular acid or acid yielding compound employed, the ratio of such acid to the seeds, the treatment time and the temperature of the treatment step. A particularly preferred boiling temperature is 70°C. for a period of about 2 hours.
Examples of the alkalis which may be employed in order to solubilise the acid-treated seeds include sodium hydroxide (caustic soda), sodium carbonate and potassium hydroxide. The preferred alkali is sodium hydroxide.
Preferably, the mixture of acid and seeds, either prior or subsequent to the, addition of alkali thereto, is subjected to filtration and/or centrifugation in either order and then allowed to stand for a period of from 10 to 60 minutes at a temperature of from 30° C. to 40° C. Thereafter, the step of removing insoluble residue from the mixture can be effected in a manner known per se such as by decantation, centrifugation and/or filtration This results in a clear solution of the fenugreek extract containing the yellow colouring principle of fenugreek.
This resulting solution of fenugreek extract containing the yellow colouring principle may be employed directly for the dyeing of textile substrates. Alternatively, the solution can be dried in air or in a vacuum drier. This presents the commercial advantage that the dried material in powder form lends itself to be' capable of storage to be employed subsequently for the re-creation of a dyeing solution. The dried material may be utilized for this purpose either per se or preferably after subjection to additional particle size reduction to below approximately 200 mesh.
Where the resulting solution of fenugreek extract is not dried, it can be treated in any known manner to separate the yellow colouring principle therefrom. This separation can conveniently be effected by salting out the colouring principle for instance with sodium chloride or by precipitating it with appropriate modification of the pH of the solution. The separated colouring matter can then be dried in air or
in a vacuum drier as described above and, where necessary, subjected to particle size reduction to below approximately 200 mesh.
According to a further embodiment of the invention, there is provided a method for the dyeing yellow of textile substrates which comprises applying to the chosen substrate an aqueous dyeing solution of the yellow colouring principle of fenugreek (Trigonella foenum-graecum L) extracted by the process herein described and boiling the aqueous solution containing the textile substrate for a pre-determined period of time while maintaining the pH thereof approximately neutral or moderately acidic.
Preferably, the step of boiling the aqueous solution containing the textile substrate being dyed is carried out at a temperature of 80° C. to 100° C. for a period of from 30 to 60 minutes.
The aqueous dyeing solution employed by the method of the invention may comprise the clear solution of fenugreek extract containing the desired yellow colouring principle resulting from the process described herein following the treatment with alkali and the step of removal of any insoluble residue. Alternatively, the aqueous dyeing solution can comprise a dispersion in water of the dried yellow colouring principle obtained after drying the clear solution of fenugreek extract resulting from the process described herein.
The textiles capable of being so dyed include cotton, viscose rayon and the like.
According to a preferred feature, the textile material to be dyed is pre-treated prior to dyeing with one or more auxiliary chemicals or mordants of synthetic or natural origin or with a mixture of mordants of both synthetic and natural origin. Alternatively, the material may be mordanted and dyed simultaneously.
Any number of mordants may be employed for this purpose. Examples thereof include tannic acid, tannins and metal salts of metals selected from iron, copper,
chromium, tin, calcium, aluminium and like. Preferred salts of these metals are the sulphates, hydroxides, halides, specifically chlorides, and complex salts of any thereof.
Where desired, the method may- include a post-dyeing treatment of the textile substrate or substrates with a mordant to fix the final colour. For this purpose, the preferred mordant employed is a soluble salt of a metal selected from copper, sodium and phosphorus with the adjustment of the pH of the dyeing solution to the range of 9 to 10.
In respect of cotton textiles, yarns or fibres, the method of the invention imparts a yellow colouration to the dyed textile material which possesses a light fastness of 3 and above as tested by AATCC testing method.
The invention will be described in detail in the following non-limitative Examples.
Example 1
EXTRACTION OF THE YELLOW COLOURING PRINCIPLE INHERENT IN THE SEEDS OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L)
100 g. of crushed fenugreek seeds were placed in an appropriate container. Next, 30 ml. of nitric acid were added to the crushed seeds with thorough stirring. The stirred mixture of acid and seeds was allowed to stand for 10 minutes whereafter 500 ml. of water were added thereto. The aqueous mixture was boiled for 60 minutes and the pH adjusted to between 10 and 11. The boiled solution was' filtered to remove any insoluble residue and leave a clear solution of fenugreek extract containing the yellow colouring principle thereof. The resulting solution was dried under vacuum to provide the desired yellow colouring principle of fenugreek (Trigonella foenum-graecum L).
Example 2
DYEING OF COTTON YARN WITH THE YELLOW COLOURING PRINCIPLE OF FENUGREEK (TRIGONELLA FOENUM-GRAECUM L)
Into 500 ml. of the boiled and filtered dye solution of Example 1, there were immersed 100 g. cotton yarn. The cotton yarn was maintained in the dyeing solution for 60 minutes at 80°C. during which period 2% copper sulphate and 7% trisodium phosphate were added so as to adjust the pH of the solution to 9.
The resulting dyed cotton yarn exhibited a bright lemon yellow colour having a light fastness of 3 and above when measured on a light fastness tester having a xenon arc lamp simulating the sun.
The invention will now be defined in the claims which follow and which must not be interpreted as limitative of the scope thereof.

WE CLAIM:
1. A process for the extraction of the yellow colouring principle of fenugreek
(Trigonella foenum-graecum L) which comprises treating fenugreek seeds with
one or more acids or a source capable of yielding acid such as herein described
adding to the mixture of seeds and acid a pre-determined amount of an alkali or
mixture of alkalis in order to solubilise the acid-treated seeds, removing in any
known manner any insoluble residue from the mixture to leave a clear solution of
fenugreek extract containing the desired yellow colouring principle and, where
desired, subjecting said solution to drying and recovering in any known manner
said yellow colouring principle in powder form.
2. A process as claimed in claim 1 wherein the treatment of the fenugreek
seeds is effected with a mixture of two or more acids added to the seeds either
simultaneously or sequentially with adjustment of the temperature of the reaction
accordingly.
3. A process as claimed in claim 1 or 2 wherein the acid treatment of said
seeds is effected at a temperature of from 25° C to 100° C for a period of from 10
minutes to 2 hours.
4. A process as claimed in any of claims 1 to 3 wherein the mixture of acid
and seeds is diluted with water and the acid content is provided or augmented by
a compound or salt which yields the desired acid on contact with the added water.
5. A process as claimed in claim 4 wherein the aqueous mixture of acid and
fenugreek seeds is boiled at a temperature from 60 ° C to 80 ° C for a period of
about 1 to 2 hours.
6. A process as claimed in claim 5 wherein said aqueous mixture of acid and
fenugreek seeds is boiled at a temperature of approximately 70°C for a period of
about 2 hours.
7. A process as claimed in any of claims 1 to 6 wherein the alkali employed to
solubilise the acid treated seeds is selected from sodium hydroxide (caustic soda),
sodium carbonate and potassium hydroxide.
8. A process as claimed in any of claims 1 to 7 wherein said fenugreek seeds
are in comminuted or powdered form.
9. A process as claimed in any of claims 1 to 8 wherein the treated mixture of
acid and fenugreek seeds either prior or subsequent to the addition of alkali
thereto is subjected to filtration and/or centrifugation in either order before being
allowed to stand and cool.
10. A process as claimed in claim 9 wherein any remaining insoluble residue is
removed from the cooled mixture in a manner known per se to yield said clear
solution of the fenugreek extract containing the yellow colouring principle of
fenugreek.
11. A process as claimed in any of claims 1 to 10 wherein said clear solution of
the fenugreek extract is subjected to drying in air or under vacuum to produce said
yellow colouring principle of fenugreek in powder form.
12. A process as claimed in any of claims 1 to 10 wherein said clear solution of
fenugreek extract containing the yellow colouring principle of fenugreek is treated
in any known manner to separate out said colouring principle from said solution,
e.g. by salting out said colouring principle with sodium chloride or by precipitating
it with appropriate modification of the pH of the solution, and the separated
colouring principle is recovered in a known manner and dried in air or under
vacuum colouring principle is recovered in a known manner and dried in air or
under.
13. A process as claimed in claim 11 or 12 wherein the dried yellow colouring
principle is subjected to additional particle size reduction to below approximately
200 mesh.
14. A process for the extraction of the yellow colouring principle of fenugreek
(Trigonella foenum-graecum L) substantially as herein described with reference to
foregoing Example 1.
15. Textile substrates whenever dyed by yellow colouring principle of
fenugreek (Trigonella foenum-graecum L) extracted by the process claimed in any
of claims 1 to 14.

Documents:

707-del-2001-abstract.pdf

707-del-2001-claims.pdf

707-del-2001-correspondence-others.pdf

707-del-2001-correspondence-po.pdf

707-del-2001-description (complete).pdf

707-del-2001-form-1.pdf

707-del-2001-form-2.pdf

707-del-2001-form-3.pdf

707-del-2001-gpa.pdf

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Patent Number

230759

Indian Patent Application Number

707/DEL/2001

PG Journal Number

11/2009

Publication Date

13-Mar-2009

Grant Date

27-Feb-2009

Date of Filing

26-Jun-2001

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

HAUZ KHAS, NEW DELHI-110016, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	GULRAJANI, MOHAN LAL	HOUSE 10, STREET C, IIT CAMPUS, HAUZ KHAS, NEW DELHI-110 016, INDIA
2	AGARWAL, KRISHNA KUMAR	KD-41 KAVI NAGAR, GHAZIABAD, UTTAR PRADESH, INDIA

PCT International Classification Number

A01C 1/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA