Claims:A method of producing inherently coloured silk fibres comprising natural dye pigments of curcuminoids and natural mordants comprising of combination of tannins
2. A combination of natural dye-mordant complex imparting microbial resistance properties to silkworms, increases cocoon production, silk ratio and impart antimicrobial properties to the silk textile
3. The method of claim 1, wherein the natural mordants belonging to tannins comprises Myrobolan and Pomegranate peel extracts in combination
4. The method in claim 1, wherein the dye comprises of curcuminoid extracted from dried rhizomes of Curcuma longa
5. The method in claim 1, wherein the dye-mordant complex impart colour ranges from yellow to brown in ratios to the silk gland and produce silk fibres of yellow to brown colours
6. The method in claim 2, wherein the natural dye-mordant complex reduce incidence of bacterial, fungal, protozoal and viral infection in silkworms
7. The method in claim 2, wherein the natural dye-mordant complex enhance the cocoon yield by minimum 10% , Description:This present invention discloses the development and process of inherent impregnation of natural dyes into the silk fibroin with the aid of natural mordants and optimized production of high yield silk fibres. Intrinsically coloured silk is achieved by rearing Bombyx mori.L (PM ˣ CSR2) on its natural diet Morus alba supplemented with natural dye extracts and mordant extracts. The conventional rearing method is followed with slight improvements to combat the disadvantages of the prior art. The conditions used for cultivation is as follows-temperature of 23 to 25⁰C , 70% humidity, 0.03-0.04 m/sec air flow speed and fed with Morus alba leaves.
These combination of natural dye of choice with mordants are fed to Bombyx mori which incorporates the dye into the fibroin and impregnates the dyes into the silk fibres while producing it.
Natural dyes may be selected from the natural pigment Indigoid dyes CI 75780 Natural blue, Anthraquinone dyes CI 75330, Naphtha quinone dyes like juglone CI 75500, Flavanoid dyes like luteolin CI 75590, Quercitrin CI 75730, Carotenoid groups not limited to Beta Carotene, Lutein, Xanthophyll, Lycopene, Capsanthin, anthocyanin, Caramel, Curcumin, Alpha Carotene, Crocin, Bixin; C25H30O4, Nor bixin; C24H28O4, 5 hydroxynaphtha quinone, 1,2 dihydroxy anthtaquinone, Cyanidine-3-glucoside: C21H21O11+, triaryl carbonium , Bheta naphthol, Fast red toner, Beta naphthol + Baso4, Eosin YS, Malachite , green hydrochloride, Violaxanthin, zeaxanthin, Marrakich red, Cuttack silver, Indigo blue, Wisdom orange, Crafty brown, Capsanthin, Capsorubin, etc., from natural sources not limited to Annatto seeds, Babchi, Gerbera petals, Cinnamon, Paprika, Cauliflower rind, Onion peel, Pumpkin peel, Beetroot, Yellow rose, Manjista, Red rose, Pomegranate peel, Gallnut, Saffron, Nut brown etc.,
Natural mordants are used for fixating the natural dyes to the silk fibres. This additional step of fixating the natural dyes is known as mordanting. The term “mordant” refers to the natural/permissible/eco-friendly elements such as but not limited to alum, iron, tannins such as myrobolan of ellagitannin type from but not limited to oak galls, pomegranate rinds, sumac and other vegetable sources like the bark, leaves, fruits and galls.
The above given pigments, mordants and sources are only exemplary and further selective extracts may form part of the present invention.
The concentrations of the mordant used is optimized based on the depth of the shade required for the production of dyed fibres.
In one embodiment of the present invention the natural dye is selected from Diaroylmethane class such as Curcumin- 1,7-bis(4- hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione from Curcuma longa. Turmeric consists of various molecular constituents, including three gold colour alkaloidal curcuminoid, curcumidesmethoxy curcumin and bisdemethoxy curcumin. Mixture of the 3 components called the curcuminoids have in total pharmacological and health benefits. Curcumin has a good dyeing effect and produces a bright yellow colour. The curcuminoids contain a plurality of double bonds, a phenolic hydroxyl group and a carbonyl group, and has a strong chemical reaction property, and is a slightly acidic phenolic substance. Curcuminoids have a bright yellow color. The Curcuminoids are extracted through methods such as not limited to solvent extraction with ethanol, methanol and combination thereof, Supercritical fluid extraction technology etc., to yield yellow dye extraction turmeric. Preferably the turmeric rhizomes are subjected to drying techniques to produce dry rhizomes of moisture less than 10%, followed by pulverization to produce fine powder ready for extraction. The extract so obtained comprises Curcumin-the dye component with molecular weight lesser than 400g/mol, ideal for impregnation into the silk gland.
In one embodiment of the invention the natural mordant are extracted from the sources of Terminalia chebula and Punica granatum. Dried myrobolan (Terminalia chebula) fruits have high tannin content and suitable as mordant to form dye-mordant complex to impregnate the silk gland with the dye. Tannins are outlined as polyphenolic compounds containing phenoplast radical teams to modify them to make effective crosslink between proteins and alternative macromolecules. It is also an excellent antifungal and antimicrobial agent used for ages in the Indian medicine. The myrobolan comprises of tannins of the type ellagitannin responsible for mordanting and imparting darker shares. Peels of Punica granatum comprises of ellagic tannins responsible for the wide range of mordanting effect on natural dyes. The dried fruits and peel of the Terminalia chebula and Punica granatum respectively are preferably ground and extracted through technology such as and not limited to aqueous extraction, solvent extraction and supercritical fluid extraction to yield pure extracts of high purity.
In one embodiment of the invention, the natural dye-mordant complex is such that but no limiting to imparting shades of colours to the silk gland, producing dyed silk fibres inherently, increases dye fastness in conjunction to increasing the silkworms resistance to infections, producing fibres with antimicrobial and pharmacological properties. The combination when consumed by the silkworms also enhances the overall performance of the worms facilitating the production of silk fibres with no detrimental impact on the silk properties, increased silk ratio, enhanced silk yield, sheen, texture and quality.
In one embodiment of the invention, the natural dye-mordant complex comprising of curcuminoids and tannins enhance the resistance in the silkworms which results in lesser incidence of bacterial, fungal, protozoal and viral infestation hampering the cocoon yield and leading to economic loss. It in turn, enhances the crop yield by at least 10%, increases the overall performance of the silkworms and promotes economic benefit to the sericulture farmers.
In accordance to embodiments of the present invention the natural dye and mordant are extracted selectively to derive a formulation for application on silkworms.
The feeding period of the desired dye-mordant complex in combination is 3-4 times a day regular intervals from 5th instar.
In the present invention, the curcuminoid extracts of the natural dye can be used in varying concentrations of 50ppm to 500ppm in combination with the mordant complex of tannins derived from myrobolan and pomegranate peel in varying concentrations to attain fibres of colours varying from the shades of light yellow, yellow, dark yellow, light brown and dark brown.
This combination is sprayed on the late instar silkworms feeding on the natural diet Morus alba or it can be prepared by dipping the Morus alba in the pigment solution and feeding the silkworms the same. Any method of application can be used as long as the dye is sufficiently soluble and the method of extraction is feasible. Examples of such methods of extraction are but not limited to water extraction which include regular drinking water, deionized water or filtered wate, methanol, ethanol or the supercritical fluid extraction technique. As the silkworm feeds on this, the dye of choice depending on the dye-mordant complex and concentration, get impregnated into the fibroin and becomes coloured. In addition to this, the dye-mordant complex also enhances the consumption capacity, thus, increasing the silk yield and quality. Further to this, the silkworm starts producing violet colour silk fibres with silk content of 15% more than the conventional technique, with increased tensile strength, air permeability, dye fastness etc.,
It is affirmed that the natural dye-mordant complex incorporates into the fibroin silk gland and is thus superior to the existing techniques where the silk is only taken up by sericin which is washed off during the degumming process. Thus, this inherent dyeing process is feasible, cost effective, environmental friendly and economical to the farmers engaged in this activity.
The silk fibre thus inherently produced has better yield, quality, colour fastness and the general thickness and other properties of silk is maintained.
Post cocoon production, the cocoon is subjected to boiling water treatment known as degumming, where sericin is removed in this process. Degumming is a general process and any process known in the prior art for degumming done in the presence of an alkali can be used here. The resulting silk fibre is of improved quality, degummed, shiny, inherently coloured with improved colour fastness and ready for textile application.
Thus, in accordance to the embodiments of the present invention, ecologically harmful step of dyeing the in silk industry can be eliminated and a uniform, high quality, increased yield coloured silk fibre with no detrimental impact on the silk properties can be achieved inherently by the silkworms.
EXAMPLES:
In order to implement the present invention and for better understanding, particular embodiments is being explained below through non-limiting examples. It is also understood that the modification of the detail may be done without deviating from the scope of the invention.
Examples of method of production, formulation and combination to produce desired colour of choice that may be used
Example 1:
Solvent extracted Curcuma longa (Methanol at 25℃) dye at 200 ppm was formulation in presence of selected mordants for colour of choice. Mordants used are Myrobolan at 1% and Pomegranate seed extract at 3% in aqueous solution. 600ml of this aqueous solution is sprayed over 1kg of Morus alba fed to the 5th instar silkworm larvae at 1st, 4th, 6th and 8th hour intervals. After the 8th hour colour change was observed on the larval body. The silk gland dissected also depicted colour change from general green to yellowish brown. The silkworms started inherently producing yellow-brown shade cocoons by the 9th day of the 5th instar. The fibre inherently produced depicted an enhanced silk yield of 10%, shiny texture after degumming

Example 2:
Supercritical fluid extract of Curcuma longa dye at 50 ppm was formulation in presence of selected mordants for colour of choice. Mordants used are Supercritical fluid extracts of Myrobolan at 1% and Pomegranate seed extract at 1.5% in aqueous solution. 200ml of this aqueous solution is sprayed over 1kg of Morus alba fed to the 5th instar silkworm larvae at 1st, 4th, 6th and 8th hour intervals. After the 8th hour colour change was observed on the larval body. The silk gland dissected also depicted colour change from general green to light yellow. The silkworms started inherently producing yellow shade cocoons by the 9th day of the 5th instar. The fibre inherently produced depicted an enhanced silk yield of 12%, shiny texture after degumming
Example 3:
The yellow to brown shades of silk fibre produced comprises varying concentrations of Curcuma longa dye extract (50 ppm to 300 ppm) with fixatives (0.5% to 5%) extracted through techniques such as but not limited to solvent extraction (ethanol, methanol, hexane) and supercritical fluid extraction technology. This silk fibre has the benefits of antimicrobial, antifungal and other pharmacological properties imparting such benefits to the textiles and yarn woven. In addition to this, the silk fibres showcase better permeability, silk quality, texture, silk ratio, cocoon yield and excellent dye fastness. The silkworms also showcased better performance, lesser incidence of Flacherie disease, bacterial, fungal, viral other protozoal infections
The invention has been described broadly and each of the groups and subgroups forms a part of the invention. This includes the generic description of the invention regardless of whether or not the excised material is specifically recited herein or not.