Claims:

1. A method of preparing indigo water colour, the method comprising
preparing a paste of one or more binders with hot water;
mixing an indigo dye with the paste to form a mixture; and
treating the mixture with a compound selected from glycerine and methyl cellulose.

2. The method as claimed in claim 1, wherein the binder is selected from gum arabic and polyethylene glycol.

3. The method as claimed in claim 1 wherein the temperature of water is in the range of from 80°C to 90°C.

4. The method as claimed in claim 1, wherein the dye is selected from natural dyes includes natural indigo, rubia, and nimbus.

5. The method as claimed in claim 4, comprising mixing natural indigo with compounds selected from sodium hydroxide, sodium dithionate, Glucose, thiourea dioxide, fructose, or a combination thereof, to obtain a reduced natural indigo dye.

6. The method as claimed in claim 1 comprising adding one or more auxiliaries selected from humectant and filler.

7. The method as claimed in claim 6, wherein the humectant is selected from honey, glucose and sugar syrup.

8. The method as claimed in claim 6, wherein the filler is dextrin.

9. The method of preparing indigo water colour as claimed in claim 1 in the form of a cake, the method comprising:
mixing natural indigo with sodium hydroxide and sodium dithionate as claimed in claim 5 to obtain a paste of reduced natural indigo;
adding gum Arabic comprising water to the paste to form a mixture;
treating the mixture with glycerine; and
drying for 24-48 hours to form water colour cake of reduced natural indigo dye.

10. An indigo dye water colour composition, the composition comprising
an indigo dye;
one or more binder; and
glycerine.

11. The composition as claimed in claim 11, wherein the indigo dye is selected from natural indigo or indigo derivatives selected from indigo, rubia, and nimbus.

12. The composition as claimed in claim 11, wherein the binder is selected from gum Arabic and polyethylene glycol.

13. The composition as claimed in claim 1, wherein the binder is mixed with normal or hot water.

14. The composition as claimed in claim 11 optionally comprising sodium hydroxide and sodium dithionate.

15. The composition as claimed in claim 11, wherein the composition is in form of a cake comprising natural indigo, sodium hydroxide, sodium dithionate, gum Arabic mixed with water and glycerine.

16. The composition as claimed in claim 11, wherein the composition is in form of a liquid comprising indigo, gum Arabic mixed with water and glycerine.

17. The composition as claimed in any of the preceding claims comprising
2 – 15 parts of dye;
30 – 60 parts of one or more binder;
30 – 60 parts of water;
8 – 10 parts of glycerine;
2 – 15 parts of sodium hydroxide; and
2 – 16 parts of sodium dithionate.

18. The composition as claimed in any of the preceding claims additionally comprising one or more auxiliaries selected from humectant and filler.

19. The composition as claimed in claim 18, wherein the humectant is selected from honey, glucose and sugar syrup.

20. The composition as claimed in claim 18, wherein the filler is dextrin.
, Description:

FORM 2
THE PATENTS ACT,
1970 (39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10, Rule 13]

A METHOD OF PREPARING NATURAL DYE BASED WATER COLOUR;

ARVIND LIMITED, A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS NARODA ROAD, AHMEDABAD - 382345, GUJARAT, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
FIELD OF INVENTION

The present invention provides method of preparing watercolor solution. More particularly, the present invention provides indigo based water colour.

BACKGROUND OF INVENTION

Mostly water colours which are available in the market are based on pigment. The pigment colour will not provide a faded look naturally. Further, the pigment colours suffer from a drawback of being toxic to highly toxic.

Therefore, there is an unmet need for a process of preparation of a water colour that will give different hue or tone of colour with time, and which is more sustainable and non-hazardous.

OBJECT OF INVENTION

An object of the invention is to provide a method of preparing indigo watercolor.

Another object of the present invention is to provide an indigo watercolor composition.

SUMMARY OF INVENTION

An aspect of the present invention relates to a method of preparing indigo water colour, the method comprising the steps of –
i. preparing a paste of one or more binders with hot water,
ii. mixing an indigo dye with the paste to form a mixture,
iii. treating the mixture with a compound selected from glycerine and methyl cellulose.

Another aspect of the present invention relates to an indigo dye watercolor composition comprising an indigo dye, one or more binder and glycerine.

It is understood that the embodiments listed hereinabove are not intended to be limiting to the scope of the present invention, nor is this summary intended to identify the essential features of the present invention. A person skilled in the art would also understand that there are several more embodiments of this inventions other than those enlisted here. The present invention will become clearer with the reading of the following description.

DESCRIPTION OF DRAWINGS

FIGURE.1: A - Synthetic Indigo; B, F, G, H - Natural Indigo with different concentration and hue of the water colour as per the present invention, C – Rubia water colour as per the present invention; D – combination of Nimbus and Rubia water colour as per the present invention; E – Nimbus water colour as per the present invention.

DETAILED DESCRIPTION OF INVENTION

The present invention is directed to a method of preparing indigo water colour, the method comprising the steps of –
preparing a paste of one or more binders with hot water;
mixing an indigo dye with the paste to form a mixture; and
treating the mixture with a compound selected from glycerine and methyl cellulose.

The binder is selected from gum Arabic and polyethylene glycol.

Hot water has a temperature in the range of 80-90 ?.

The dye is selected from natural indigo, rubia and nimbus.

In an embodiment of the present invention, the natural indigo is mixed with compounds selected from sodium hydroxide, sodium dithionate, glucose, thiourea dioxide, fructose, or a combination thereof, to obtain a reduced natural indigo dye.

In an embodiment of the present invention, one or more auxiliaries selected from humectant and filler are added.

The humectant is selected from honey, glucose, and sugar syrup.

The filler is dextrin.

In an embodiment of the present invention the water colour is prepared in the form of a cake, the method comprising the steps of –
mixing natural indigo with sodium hydroxide and sodium dithionate to obtain a paste of reduced natural indigo;
adding gum Arabic comprising water to the paste to form a mixture;
treating the mixture with glycerine; and
drying for 24-48 hours to form water colour cake of reduced natural indigo dye

The method of the present invention involves preparation of a binder and reduction of the indigo followed by mixing process and allow to settle for 24 hours.

The commercially used processes involve additional steps of adding chemicals like plasticizer, filler, humectant, other additives, which may be harmful to human beings. The present invention does away with the need of the steps of adding fillers, humectant, etc.

In an embodiment of the invention an indigo dye water colour composition comprises of
an indigo dye;
one or more binder; and
glycerine.

The composition optionally comprises of one or more auxiliaries selected from humectant and filler.

The natural dye is selected from natural indigo, rubia, and nimbus.

The binder is selected from gum arabic and polyethylene glycol.

The binder is mixed with normal or hot water.

The composition optionally comprises sodium hydroxide and sodium dithionate.

In an embodiment of the present invention, the composition is in form of a cake comprising natural indigo, sodium hydroxide, sodium dithionate, gum Arabic mixed with water and glycerine.

In an embodiment of the present invention, the composition comprises
2-15 parts of dye;
30-60 parts of one or more binder;
30-60 parts of water;
8-10 parts of glycerine;
2-15 parts of sodium hydroxide; and
2-16 parts of sodium dithionate

In an embodiment of the present invention, the composition comprises one or more auxiliaries.

In an embodiment, the present invention provides a method of preparing reduced natural indigo dye cake, the method comprising the steps of –
i. Adding 30-60 parts of hot water into 30-60 parts gum Arabic with stirring to obtain a first homogeneous paste of gum Arabic,
ii. Mixing 2-15 parts of natural indigo dye, 2-15 parts of sodium hydroxide and 2-15 parts of sodium dithionite in the first homogeneous paste to obtain a second homogeneous paste,
iii. Adding 8-10 parts of glycerine to the second homogenous paste to obtain third homogeneous paste,
iv. Drying the third homogenous paste for 24-48 hours to obtain reduced natural indigo dye cake.

In an embodiment, the present invention provides a method of preparing reduced natural indigo dye solution, the method comprising the steps of –
i. Adding 30-60 parts of hot water into 30-60 parts gum Arabic with stirring to obtain a first homogeneous solution of gum Arabic,
ii. Mixing 2-15 parts of natural indigo dye, 2-15 parts of sodium hydroxide and 2-15 parts of sodium dithionite in the first homogeneous solution to obtain a second homogenous solution, and
iii. Adding 8-10 parts of glycerine to the second homogenous paste to obtain reduced natural indigo dye solution.

Similarly, another embodiment of the present invention also provides a method of preparing rubia, the method comprising the steps of –
i. Adding 30-60 parts parts of hot water into 30-60 parts parts gum Arabic with stirring to obtain a first homogeneous solution of gum Arabic,
ii. Mixing 2-15 parts of rubia in the first homogeneous solution to obtain a second homogenous solution, and
iii. Adding 8-10 parts of glycerine to the second homogenous solution to obtain rubia.

Hot water allows for dissolution of binder or gum Arabic in water and therefore, in order to make homogenous paste hot water (Temp-70-80 C) is required.

Gum Arabic acts a binder in the composition. Polyethylene glycol can be used as an alternative to gum Arabic as a binder.

Another embodiment of the present invention provides a reduced natural indigo dye cake comprising:
- 30-60 parts of Gum Arabic,
- 30-60 parts of Hot water,
- 2-15 parts of Dye,
- 2-15 parts of Sodium Hydroxide,
- 2-15 parts of Sodium Dithionite, and
- 8-10 parts of Glycerine.

Yet another embodiment of the present invention provides a reduced natural indigo dye solution comprising:
- 30-60 parts of Gum Arabic,
- 30-60 parts of Hot water,
- 2-15 parts of Dye,
- 2-15 parts of Sodium Hydroxide,
- 2-15 parts of Sodium Dithionite, and
- 8-10 parts of Glycerine.

Further, an embodiment of the present invention provides an rubia comprising:
- 30-60 parts of Gum Arabic,
- 30-60 parts of Hot water,
- 2-15 parts of Dye, and
- 8-10 parts of Glycerine.

Similarly, another embodiment of the present invention provides a rubia dye solution comprising:
- 30-60 parts of Gum Arabic,
- 30-60 parts of Hot water,
- 2-15 parts of Dye, and
- 8-10 parts of Glycerine.

In an embodiment, glycerine can be replaced with methyl cellulose.

The water colour of the present invention is based on reduced natural indigo dye and rubia, and nimbus. The advantage of incorporation of reduced natural indigo into water colour is to get a different tone of blue colour because it changes its hue or tone with time when it is applied on paper or canvas or any other object. Further, as it is natural dye, it is more sustainable and non-hazardous.

The commercially used water colours involve additional chemicals like plasticizer, filler, humectant, other additives, which may be harmful to human beings. The present invention does away with the need for additional fillers, humectant, etc.

The making process of water colour consists of preparation of binder and then adding of pigment or dyes and glycerine or other auxiliary into the binder.

EXAMPLES:

It is understood that the examples listed below are for illustration only and are not intended to be limiting to the scope of the present invention.

Example 1

• Preparation of binder
41 parts of solid powder of gum Arabic and 41 parts of hot water were mixed along with stirring until a homogeneous paste of gum Arabic (first homogeneous paste) was obtained.

• Preparation of Reduced Natural indigo
3 parts of natural indigo dye, 3 parts of Sodium Hydroxide and 3 parts of Sodium Dithionite were added into the binder gum Arabic paste along with stirring until a homogeneous paste was obtained (second homogeneous paste). To this homogeneous paste, 9 parts of Glycerine was added, and the paste thus obtained (third homogeneous paste) was dried for 36 hours. After drying, the reduced natural indigo dye cake was obtained.

Table 1: Composition of Water colour
Gum Arabic 41 parts
Hot water 41 parts
Natural Indigo Dye 3 parts
Sodium Hydroxide 3 parts
Sodium Dithionite 3 parts
Glycerine 9 parts

Example 2
• Preparation of binder
43 parts of solid powder of gum Arabic and 43 parts of hot water were mixed along with stirring until a homogeneous paste of gum Arabic (first homogeneous paste) was obtained.
• Preparation of Reduced Natural indigo
2 parts of natural indigo dye, 2 parts of Sodium Hydroxide and 2 parts of Sodium Dithionite were added into the binder gum Arabic paste along with stirring until a homogeneous paste was obtained (second homogeneous paste). To this homogeneous paste, 8 parts of Glycerine was added, and the paste thus obtained (third homogeneous paste) was dried for 36 hours. After drying, the reduced natural indigo dye cake was obtained.

• Table 2: Composition of Water colour
Gum Arabic 43 parts
Hot water 43 parts
Natural Indigo Dye 2 parts
Sodium Hydroxide 2 parts
Sodium Dithionite 2 parts
Glycerine 8 parts

Example 3
• Preparation of binder
43 parts of solid powder of gum Arabic and 43 parts of hot water were mixed along with stirring until a homogeneous paste of gum Arabic (first homogeneous paste) was obtained.
• Preparation of Reduced Natural indigo
2 parts of natural indigo dye, 2 parts of Sodium Hydroxide and 2 parts of Sodium Dithionite were added into the binder gum Arabic paste along with stirring until a homogeneous paste was obtained (second homogeneous paste). To this homogeneous paste, 8 parts of Glycerine was added, and the paste thus obtained (third homogeneous paste) was dried for 36 hours. After drying, the reduced natural indigo dye cake was obtained.

Table 3: Composition of Water colour
Gum Arabic 42 parts
Hot water 42 parts
Natural Indigo Dye 2 parts
Sodium Hydroxide 2 parts
Sodium Dithionite 2 parts
Glycerine 10 parts

Example 4
• Preparation of binder
12 parts of carboxymethyl cellulose (CMC) and 76 parts of hot water were mixed along with stirring until a homogeneous paste of CMC (first homogeneous paste) was obtained.
• Preparation of Water color with rubia
3 parts rubia dye were added into the binder paste of carboxymethyl cellulose (CMC) along with stirring until a homogeneous paste was obtained (second homogeneous paste). To this homogeneous paste, 9 parts of Glycerine was added, and the paste thus obtained (third homogeneous paste) was dried for 36 hours. After drying, the rubia dye cake was obtained.

Table 4: Composition of Water colour
CMC 12 parts
Hot water 76 parts
Rubia 3 parts
Glycerine 9 parts

Example 5
• Preparation of binder
12 parts of carboxymethyl cellulose (CMC) and 76 parts of hot water were mixed along with stirring until a homogeneous paste of CMC (first homogeneous paste) was obtained.
• Preparation of Water color with rubia
3 parts rubia dye were added into the binder paste of carboxymethyl cellulose (CMC) along with stirring until a homogeneous paste was obtained (second homogeneous paste). To this homogeneous paste, 9 parts of Glycerine was added, and the paste thus obtained (third homogeneous paste) was dried for 36 hours. After drying, the nimbus dye cake was obtained.

Table 5: Composition of Water colour
CMC 12 parts
Hot water 76 parts
Nimbus 3 parts
Glycerine 9 parts

The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to a person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.