Claims:Claims:

1. A cost-effective and an eco-friendly dyeing method for a material of polyester-cotton blends;
the method comprising:
a) subjecting the material to hot boiling in the presence of auxiliaries to obtain a treated material;
b) subjecting the treated material obtained in step (a) to polyester dyeing in the bath comprising disperse dyes and auxiliaries to dye a polyester fiber component of the material to obtain a dyed material;
c) subjecting the dyed material obtained in step (b) to a pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath to obtain a cationized dyed material;
d) subjecting the cationized dyed material obtained in step (c) to hot wash to obtain a washed cationized dyed material;
e) subjecting the washed cationized dyed material obtained in step (d) to neutralization to obtain a neutralized cationized dyed material;
f) subjecting the neutralized cationized dyed material obtained in step (e) to cotton dyeing in the bath comprising reactive dyes, auxiliaries and alkali to dye a cotton fiber component of the cationized dyed material to obtain a dyed material;
g) subjecting the dyed material obtained in step (f) to wash with water to obtain a washed dyed material;
h) subjecting the washed dyed material obtained in step (g) to neutralization to obtain a neutralized dyed material;
i) subjecting the neutralized dyed material obtained in step (h) to treatment with wash off agent to obtain a treated dyed material;
j) subjecting the treated dyed material obtained in step (i) to hot wash to obtain a washed dyed material; and
k) subjecting the washed dyed material obtained in step (j) to wash with water to obtain a dyed material;
the dyed material has good color fastness to wash and to both wet rubbing and dry rubbing properties without sacrificing the shade of the dyed color;
said method reduces water consumption, effluent generation, steps of dyeing, power consumption, energy consumption, waste disposal, dyeing cost and pollution; thereby making the method cost-effective and eco-friendly.

2. The method as claimed in claim 1, wherein the hot boiling step (a) comprises loading the bath with material and water, adding auxiliaries selected from wetting agents, dispersing agents and lubricating agents in the bath, raising the temperature of the bath to 80°C to 95°C, running the material in the bath for at least 5 to 20 minutes of the residence time followed by cooling down the bath to 78°C and draining the bath to obtain a treated material.

3. The method as claimed in claim 1, wherein the step (b) comprises loading the treated material obtained in step (a) and water, adding auxiliaries in the dye bath, checking and maintaining the pH of the bath in the range of 4 to 6, heating the bath to 60°C, adding the disperse dyes in the bath, raising the temperature of the dye bath to 90° C then to 110°C finally to 135°C followed by running the material in the bath for at least 25 to 50 minutes of the residence time to dye polyester fiber component of the material, cooling the dye bath from 135°C to 74°C, and draining the bath to obtain a dyed material.

4. The method as claimed in claim 1, wherein the step (c) comprises loading the dyed material obtained in step (b) and water in a bath followed by adding auxiliaries, raising the temperature of the bath to 60°C, adding alkali to the bath to adjust the pH of the bath in the range of 10 to 14, running the bath for at least 5 to 15 minutes, adding 10 to 90 gm/liter of cationizing agent to the bath followed by running the bath for at least 5 to 15 minutes, raising the temperature of the bath to 85°C at the rate of 3°C/minute followed by running the material in the bath for at least 25 to 60 minutes of the residence time, cooling the bath to 74°C, adding a reducing agent followed by raising the temperature to 80°C, running the material in the bath for at least 15 to 30 minutes of the residence time, cooling the bath to 74°C and draining the bath to obtain a cationized dyed material.

5. The method as claimed in claim 4, wherein the step (c) comprises loading the dyed material obtained in step (b) and water in a bath followed by adding the auxiliaries selected from dispersing agents, wetting agents and lubricating agents, raising the temperature of the bath to 60°C, adding the alkali to the bath to adjust the pH in the range of 11.5 to 12.5, running the bath for at least 10 minutes, adding 20 to 80 gm/liter of the cationizing agent to the bath followed by running the bath for at least 10 minutes of residence time, raising the temperature of the bath to 85°C at the rate of 3°C/minute followed by running the bath for at least 30 to 45 minutes of the residence time, cooling the bath to 74°C, adding the reducing agent followed by raising the temperature to 80°C, running the material in the bath for at least 15 to 25 minutes of the residence time, cooling the bath to 74°C, and draining the bath to obtain the cationized dyed material.

6. The method as claimed in claim 1, wherein the step (d) comprises loading the cationized dyed material obtained in step (c) and water in the bath followed by heating the bath to raise the temperature in the range of 75°C to 90°C, running the material in the bath for at least 8 to 15 minutes of residence time and draining the bath after wash to obtain a washed cationized dyed material.

7. The method as claimed in claim 1, wherein the step (e) comprises loading the washed cationized dyed material obtained in step (d) and water followed by adding acid to the bath to adjust the pH of the bath in the range of 4 to 6, running the material in the bath for at least 5 to 15 minutes of the residence time while maintaining the pH in the range of 4 to 6 and draining the bath to obtain a neutralized cationized blend material.

8. The method as claimed in claim 1, wherein the step (f) of the cotton dyeing comprises loading the neutralized cationized blend material obtained in step (e) and water in the bath, raising the temperature of the bath to 50° C, dosing the reactive dyes along with auxiliaries at 50° C, adding first alkali followed by addition of second alkali to adjust the pH of the bath in the range of 9 to 12.5, raising the temperature of the dye bath from 50° C to 60° C at the rate of 1.5°C/minute followed by running the material in the bath for at least 25 to 60 minutes of the residence time to dye cotton fiber component of the material and draining the bath to obtain a dyed material.

9. The method as claimed in claim 9, wherein the step (f) comprises loading the neutralized cationized blend material obtained in step (e) and water in the bath, adding auxiliaries selected from lubricating agents, dye bath conditioners and buffers to the bath, raising the temperature of the dye bath to 50° C, dosing the reactive dyes at 50° C over 20 minutes, running the material in the bath for at least 20 minutes of the residence time, adding first alkali of sodium carbonate over 30 minutes followed by addition of second alkali of sodium hydroxide over 20 minutes to adjust the pH of the bath in the range of 10.5 to 11.5, raising the temperature of the bath from 50° C to 60° C at the rate of 1.5°C/minute followed by running the material in the bath for at least 45 to 55 minutes of the residence time to dye cotton fiber component of the material and draining the bath to obtain the dyed material.

10. The method as claimed in claim 1, wherein the step (g) comprises loading the dyed material obtained in step (f) and water in the bath, running the bath for at least 5 to 15 minutes of the residence time at the temperature in the range of 25°C to 30°C and draining the bath after treatment to obtain a washed dyed material.

11. The method as claimed in claim 1, wherein the step (h) comprises loading the washed dyed material obtained in step (g) and water in the bath followed by addition of acid to it to adjust the bath pH in the range of 4.5 to 6.5, running the material in the bath for at least 5 to 15 minutes of the residence time while maintaining pH in the range of 4.5 to 6.5 and draining the bath after the treatment to obtain a neutralized dyed material.

12. The method as claimed in claim 1, wherein the step (i) comprises loading the neutralized dyed material obtained in step (h) and water in the bath followed by adding a wash off agent to it followed by heating the bath to raise the temperature in the range of 80°C to 100°C, running the material in the bath at the maintained temperature for at least 5 to 15 minutes of the residence time and draining the bath to obtain a treated dyed material.

13. The method as claimed in claim 1, wherein the step (j) comprises loading the treated dyed material obtained in step (i) and water in the bath followed by heating the bath to raise the temperature in the range of 80°C to 90°C, running the material in the bath for at least 5 to 15 minutes of the residence time and draining the bath after wash to obtain a washed dyed material.

14. The method as claimed in claim 1, wherein the step (k) comprises loading the dyed material obtained in step (j) and water in the bath, running the material in the bath for at least 5 to 15 minutes of the residence time at the temperature in the range of 25°C to 30° C and draining the bath upon wash to obtain a dyed material.

15. The method as claimed in claim 1, wherein the method comprises dyeing the polyester fibre component of the material followed by pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath followed by dyeing the cotton fibre component of the material, reduces
• number of steps to 11,
• 24 to 32 % of fresh water consumption,
• 25 to 32 % of effluent generated and drained,
• 8 to 14% of the total time consumption,
• 7 to 18 % of cost of dyeing; and
• eliminates the step of dye-fixing and use of glauber's salt;

Dated this 31st day of October 2019

(Dr. Shilpa Gharve)
Agent of the Applicant
, Description:FIELD OF INVENTION:
The present invention relates in general to a dyeing method of polyester-cotton blends.
In particular, the present invention relates to a cost-effective and eco-friendly dyeing method of polyester-cotton blends, particularly the material is subjected to polyester dyeing followed by combining a pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath subsequently subjecting the material to cotton dyeing in the absence of electrolyte/salt achieving good fastness properties.
The present invention has several advantages including but not limited to reducing water consumption, effluent generation, waste disposal, time consumption, chemical consumption, energy consumption, cost of dyeing, etc., thereby making the current method cost-effective and eco-friendly.

BACKGROUND OF THE INVENTION:
A wide variety of natural and man-made fabrics are available today. But all fabrics are not perfect and have some good, fair or poor characteristics. To make perfect fabrics, the industry experts have produced blended fabrics by spinning intimate mixture of two or more fibres together in varying proportions. The blending of cellulosic fibres with man-made fibres to produce fabrics with improved characteristics has long been accepted throughout the world.
Polyester blended cotton fabric is important and popular choice of textiles used in the manufacture of clothing and other textile products due to its multi-dimensional uses and aesthetic attributes. Though this blend has a large variety of lucrative characteristics such as breathability, tear resistance and abrasion resistance, still this blend costs less than 100% cotton. However, the dyes and dyeing conditions used to dye cotton and polyester fibres are different from each other and thus it is necessary to dye blends of cotton and polyester fibres in two different dye baths.
Cotton fibres and the reactive dyes both are hydrophilic in nature. Therefore, the reactive dyes have a high degree of affinity for cellulosic cotton fibres and form a covalent chemical bond with the hydroxyl groups of cotton and exhibit excellent fastness properties. The reactive dyes used to dye cotton fibres include but not limited to the vinyl sulfone, dichloroquinoxalone, halotriazine and halopyrimidine types which are well known in the art. These reactive dyes are stable under alkaline pH conditions. Hence, the dyeing of cotton fibre with reactive dyes is generally carried out under alkaline condition at a temperature in the range of 40°C to 110°C in the presence of an electrolyte. The electrolyte promotes exhaustion of the dye from the dye bath to the cotton fibre. Further, these reactive dyes may not be thermally stable.
Unlike cotton fibres, the polyester fibres are hydrophobic and thus, they are generally dyed with hydrophobic disperse dyes. Since, the disperse dyes are sparingly soluble in water, they usually disperse in water with the aid of a dispersing agent like a surfactant in combination with other suitable auxiliaries. Generally, disperse dyes diffuse into the fibre under the influence of heat and dyeing auxiliaries to color the polyester fibre. However, disperse dyes are generally not stable at higher pH but may be stable at higher temperature. Further, dispersion of the disperse dyes may be sensitive to electrolytes which may tend to cause dispersion instability. Thus, dyeing of the polyester with disperse dye is normally carried out at pH 5-7 at a temperature in the range of 120°C to 140°C in the presence of a surfactant in combination with other auxiliaries but in the absence of the electrolyte.
Generally dyeing method comprises pre-treatment consisting of scouring and bleaching, polyester part dyeing, reduction clearing and cotton part dyeing. Although lot of research work is going on for developing efficient blend dyeing method yet two bath process is still being used mostly for polyester blend cotton dyeing.
The polyester-cotton blends are generally dyed by three well known exhaust dyeing procedures which are:
a) a conventional two bath dyeing: In the conventional two bath dyeing, the polyester-cotton blend is first subjected to a dyeing with a disperse dye in a dye bath at pH in the range of 5 to 7 at temperature in the range of 120°C to 140°C to dye the polyester fiber component of the blend. The blend is further subjected to dyeing with reactive dye in the presence of an electrolyte and an alkali in a second dye bath at the temperature in the range of 50°C to 110°C to dye the cotton fiber component of the blend.
b) a reverse two bath dyeing: In this dyeing, first dyeing the cotton fiber component of the blend with the reactive dye is followed by second dyeing of the polyester fiber component with the disperse dye in the separate dye bath. Thus, it is reverse of the conventional dyeing method.
c) a one bath, multi-step dyeing: In the one bath multi-step dyeing method, a single dye bath is prepared using reactive dye and the cotton fiber component of the blend is dyed under alkaline conditions and at low temperature in the presence of electrolyte. The dye bath is then acidified to lower the pH and a disperse dye is added and the polyester fiber component of the blend is dyed at the temperature in the range of 120°C to 130°C.
The problem of lower water solubility and dispersion to aggregate during dyeing is associated with disperse dyes and thus there are observations that some disperse dyes remain adhered on the fabric surface after polyester part dyeing. These adhered dyes on the fabric surface can adversely affect the color fastness properties of fabric and cause inevitable unevenness of subsequent processes. To avoid these mentioned problems, the alkaline reduction clearing is traditionally done after polyester part dyeing to wash-off unfixed dyes and auxiliaries from the surface of the fabric. Generally alkaline reduction clearing is carried out in the presence of alkali and reduction clearing agent at the temperature in the range of 60°C -80°C for 20-30 minutes. The commonly used alkali in the reduction clearing is sodium hydroxide and sodium bicarbonate. This reduction clearing step imparts brightness and improves color fastness properties of the dyed fabric and thus helps in maintaining the quality parameters imposed by the industry and satisfies the buyers /consumers. However, the reducing agents used for reduction clearing process are expensive and also have adverse environmental effect.
Further, to increase affinity of the reactive dyeing and to reduce wastage of reactive dyes, cotton fiber component of the blend is subjected to cationization in the presence of cationizing agent and alkali.
In conventional dyeing method, the cationization is carried out initially before dyeing cotton fiber components of the blend with reactive dyeing. Similarly the reduction clearing process is done separately after polyester part dyeing which consumes substantial volume of water, chemicals, process time thus requiring expanded production cost. Now-a-days, due to increased awareness of adverse effects on the environment competitiveness as well as cost competitiveness, industry and government are remarkably well concerned regarding the eco-friendly and efficient technological methods of dyeing due to increased pressure and demands claimed by the environmentalists, buyers and end users. As the adequate water resources are gradually diminishing alarmingly, all manufacturing plants including textile industries are trying to best use the water resources by imparting process modifications due to environmental and commercial concerns as well.
Accordingly, the alternative methods that have been devised instead of earlier convention method dyeing are as follows:
CN109610203 (A) discloses energy-saving and emission reduction dyeing process with a low bath ratio. The dyeing process comprises the following steps: pretreatment, polishing and polyester dyeing one-bath, polyester dyeing cleaning, cotton dyeing, soaping, thermal washing, and color fixation.
In CN109610203 (A), CN107794784 (A), CN106948195 (A) and CN106868894 (A), the polyester dyeing and reduction cleaning processes are combined or integrated.
Polyester-cotton blends, if dyed in a single bath may lead to non-uniform dyeing. Further, dyeing strength depends upon the amount of electrolyte and alkali used in the dye bath as well as kind of dyes and their amount and kind of fibers to be dyed. Deep shades require more dye which in turn requires more electrolyte and more alkali. The present conventional dyeing causes pollution due to high effluent generation, use of large quantity of electrolyte or salt, increase of colorant, chemical oxygen demand (COD), biological oxygen demand (BOD), total dissolved solids (TDS) and highly toxic chlorinated organic byproduct (AOX) in the stream. At the same time it consumes large quantity of water and energy. The existing art minimizes the use of electrolyte, reduces the water consumption and reduces the generation of effluent.
Accordingly, there is need to study and devise method of dyeing which focuses on the reduction of water consumption, utility consumption, chemicals consumption, process time, effluent generation, cost of dyeing, pollution, keeping all the parameters as required.

OBJECTS OF THE INVENTION:
The main object of the invention is to provide a cost-effective and eco-friendly dyeing method of material of polyester-cotton blends; wherein the material is subjected to polyester dyeing followed by subjecting the material to a pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath subsequently subjecting the material to cotton dyeing.
Another object of the invention is to provide the cost-effective and the eco-friendly dyeing method of material of polyester-cotton blends; wherein the dyeing method combines the pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath leading to reduction of water consumption, chemical consumption, effluent generation, cost of dyeing and number of steps of dyeing method; thereby making the process cost-effective and eco-friendly.
Another object of the invention is to provide the cost-effective and the eco-friendly dyeing method of material of polyester-cotton blends; wherein the dyeing method further eliminates dye-fixing leading to reduction of water consumption, effluent generation, chemicals used in the dye-fixing and number of steps of dyeing method; thereby making the process cost-effective and eco-friendly.
Yet another object of the invention is to provide the cost-effective and an eco-friendly dyeing method of material of polyester-cotton blends; wherein the dyeing method eliminates electrolyte/salt; thereby making the dyeing method eco-friendly.

Summary of the invention:
In the presently claimed invention, it is surprisingly found that the polyester-cotton blend textile material is dyed with disperse dyes followed by carrying out a pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath and finally dyeing the material with reactive dyes depending upon the desired shade to be achieved at particular temperature and pH of the bath to obtain a dyed material with a smooth texture with a desired uniform shade with good color fastness, which is otherwise very difficult to dye polyester and cotton fiber components of the blend in the absence of an electrolyte /salt or leads to compromise in dye shade, uniform dyeing, fastness properties of the material or causes increase in steps of dyeing, water consumption, chemical consumption, effluent generation, power and energy consumption as well as cost. The experiments were carried out to optimize temperature and pH of the bath and residence time of the material in the bath to dye polyester fiber component and cotton fiber component of the polyester-cotton blend material according to the invention. After the experimental, it was optimized to dye polyester-cotton blend material by dyeing the polyester fiber component of the blend material with disperse dyes along with auxiliaries at temperature of 90°C to 135°C and pH in the range of 4 to 6; loading the bath with water and the dyed material followed by raising the temperature of the bath to 60°C, adding alkali to adjust the pH of the bath to 10 to 14, running the bath for at least 10 minutes of residence time, adding 10 to 90 gm/liter of cationizing agent to the bath followed by running the bath for at least 10 minutes, raising the temperature of the bath to 85°C at the rate of 3°C/min followed by running the bath for at least 45 minutes, cooling the bath to 74°C, adding reduction clearing agent selected from sodium dithionite followed by raising the temperature to 80°C, running the bath for at least 20 minutes, cooling the bath to 74°C subsequently draining the bath to obtain a cationized dyed material followed by cotton dyeing with reactive dyes in the presence of auxiliaries at temperature of 60°C and pH in the range of 9 to 12.5 to obtain a dyed material having smooth surface, good color fastness to wash and to both dry and wet rubbing properties without sacrificing color shade with simultaneous reduction of dyeing cost. The presently claimed invention eliminates the separate reduction clearing process step diametrically and using no extra wash off chemicals. In the presently claimed invention, the pre-treatment consisting of scouring and cationization was carried out after polyester part dyeing unlike traditional process. As per our experiment and observations, the alkali used in the scouring can be used to carry out the reduction clearing as well. NaOH may be used as surface cleaning agent and reduction clearing agent used as a discoloration agent thus removing the unfixed dyes and auxiliaries from the fabric surface fulfilling the purpose the reduction clearing process without using any extra wash off chemicals like alkali and water. The method of dyeing according to the invention eliminates the use of salt/electrolyte and reduces water consumption, alkali consumption, time and number of the steps of dyeing which ultimately reduces energy, manpower, etc, thereby reducing the overall cost of the method of dyeing. Thus, the method of the presently claimed invention also reduces water consumption and effluent generation and eliminates the use of salt/electrolyte thereby reducing pollution, which is main advantage besides economic benefits.

According to the method of the invention, there is provided a cost-effective and an eco-friendly dyeing method for a material of polyester-cotton blends;
the method comprising:
a) subjecting the material to hot boiling in the presence of auxiliaries to obtain a treated material;
b) subjecting the treated material obtained in step (a) to polyester dyeing in a bath comprising disperse dyes and auxiliaries to dye a polyester fiber component of the material to obtain a dyed material;
c) subjecting the dyed material obtained in step (b) to a pre-treatment consisting of scouring and cationization simultaneously performing reduction clearing in a single bath to obtain a cationized dyed material;
d) subjecting the cationized dyed material obtained in step (c) to hot wash to obtain a washed cationized dyed material;
e) subjecting the washed cationized dyed material obtained in step (d) to neutralization to obtain a neutralized cationized dyed material;
f) subjecting the neutralized cationized dyed material obtained in step (e) to cotton dyeing in the bath comprising reactive dyes, auxiliaries and alkali to dye a cotton fiber component of the cationized dyed material to obtain a dyed material;
g) subjecting the dyed material obtained in step (f) to wash with water to obtain a washed dyed material;
h) subjecting the washed dyed material obtained in step (g) to neutralization to obtain a neutralized dyed material;
i) subjecting the neutralized dyed material obtained in step (h) to treatment with wash off agent to obtain a treated dyed material;
j) subjecting the treated dyed material obtained in step (i) to hot wash to obtain a washed dyed material; and
k) subjecting the washed dyed material obtained in step (j) to wash with water to obtain a dyed material;
the dyed material has good color fastness to wash and to both wet rubbing and dry rubbing properties without sacrificing the shade of the dyed color;
said method reduces water consumption, effluent generation, steps of dyeing, power consumption, energy consumption, waste disposal, dyeing cost and pollution; thereby making the method cost-effective and eco-friendly.

Typically, the hot boiling step (a) comprises loading a bath with material and water, adding auxiliaries selected from wetting agent, dispersing agent and lubricating agent in the bath, raising the temperature of the bath in the range of 80°C to 95°C, running the material in the bath for at least 5 to 20 minutes of the residence time followed by cooling down the bath to 78°C and draining the bath to obtain a treated material.
Typically, the material to water ratio in step (a) is 1:5 to 8 (wt./vol.), preferably 1:6 (wt./vol.).
The lubricating agent used in step (a) is selected from low foaming anionic or non-ionic lubricating agents like C12 to C14 fatty alcohol ethoxylate, EO/PO adducts, phosphate ester such as Dikapal AP Liquid and the likes.
Typically, dispersing agent used in step (a) is selected from polymeric dispersing agent such as Exhosperse HC and the likes.
Typically, wetting agent used in step (a) is selected from non-ionic wetting agent such as Exowet ES and the likes.
Typically, the hot boiling step (a) comprises loading the bath with material and water in a ratio of 1:6 (wt./vol.); adding 1 gm/liter of wetting agent, 0.7 gm/liter of dispersing agent and 0.5 gm/liter of lubricating agent in the bath; raising the temperature of the bath to 90°C; running the material in the bath for at least 10 minutes of the residence time followed by cooling down the bath to 78°C and draining the bath to obtain the treated material.

Typically, the step (b) of the polyester dyeing comprises loading the treated material obtained in step (a) and water, adding auxiliaries to the dye bath, checking and maintaining the pH of the bath in the range of 4 to 6, heating the bath to 60°C, adding the disperse dyes in the bath, raising the temperature of the dye bath to 90°C followed by heating to 110°C and finally to 135°C followed by running the material in the bath for at least 25 to 50 minutes of the residence time to dye polyester fiber component of the material, cooling the dye bath from 135°C to 74°C and draining the bath to obtain a dyed material.
Typically, the step (b) comprises loading the treated material obtained in step (a) and water in the bath followed by addition of auxiliaries to the bath, checking and maintaining the pH of the bath in the range of 4.5 to 5.5, heating the bath to 60°C, adding the disperse dyes in the bath, raising the temperature of the bath to 90° C at the rate of 3°C /minute followed by raising the temperature from 90°C to 110°C at the rate of 2.5°C/minute further raising the temperature of the bath from 110°C to 130°C at the rate of 1.5°C /minute followed by running the material in the bath for at least 25 to 45 minutes of the residence time to dye polyester fiber component of the material, cooling the dye bath from 130°C to 110°C at the rate of 1.5°C/minute followed by cooling the bath from 110°C to 90°C at the rate of 2.5°C/minute further cooling from 90°C to 74°C at the rate of 3°C/minute and draining the bath to obtain the dyed material.
Typically, the material to water ratio in step (b) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).
Typically, the disperse dyes used in step (b) are selected from anthraquinonoid and azo-based disperse dyes. These dyes are also used either alone or in combination depending on the desired shade. For example, to achieve black color, Coralene brilliant red HP3BS and Coralene black RLS may be used in a specific proportion.
Typically, the auxiliaries are selected from lubricating agents like fatty alcohol ethoxylate such as Dep. ACA B-Liq. and the likes; dye bath conditioners such as Sunsoft LM7, Albatex AB55 and the likes; dispersing agents such as Levocol CWS and the likes; pH regulators such as acetic acid and the likes; buffers such as sodium acetate, Orgakol TSP, and the likes.

Typically, step (c) comprises pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath, wherein step (c) comprises loading the dyed material obtained in the step (b) and water in a bath followed by adding auxiliaries, raising the temperature of the bath to 60°C, adding alkali to adjust the pH of the bath in the range of 10 to 14, running the bath for at least 5 to 15 minutes, adding 10 to 90 gm/liter of cationizing agent to the bath followed by running the bath for at least 5 to 15 minutes, raising the temperature of the bath to 85°C at the rate of 3°C/minute followed by running the material in the bath for at least 25 to 60 minutes of the residence time, cooling the bath to 74°C, adding a reducing agent followed by raising the temperature to 80°C, running the material in the bath for at least 15 to 30 minutes of the residence time, cooling the bath to 74°C and draining the bath to obtain a cationized dyed material.
Typically, step (c) comprises loading the dyed material obtained in step (b) and water in a bath followed by adding the auxiliaries selected from dispersing agent, wetting agent and lubricating agent, raising the temperature of the bath to 60°C, adding the alkali to the bath to adjust the pH in the range of 11.5 to 12.5, running the bath for at least 10 minutes, adding 20 to 80 gm/liter of cationizing agent to the bath followed by running the bath for at least 10 minutes, raising the temperature of the bath to 85°C at the rate of 3°C/minute followed by running the material in the bath for at least 30 to 50 minutes of the residence time, cooling the bath to 74°C, adding the reducing agent followed by raising the temperature to 80°C, running the material in the bath for at least 15 to 25 minutes of the residence time, cooling the bath to 74°C and draining the bath to obtain the cationized dyed material.
Typically, the material to water ratio in step (c) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).
Typically, the alkali used in step (c) is selected from sodium hydroxide, potassium hydroxide and the likes.
Typically auxiliaries used in step (c) is selected from polymeric dispersing agent such as Exhosperse HC and the likes, wetting agent like non-ionic wetting agent such as Exowet ES and the likes, anionic and non-ionic lubricating agent like fatty alcohol ethoxylate such as Dep. ACA B-Liq and the likes.
The cationizing agent used in step (c) is selected from 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMAC).
Typically, the reducing agent used in step (c) is selected from sodium dithionite and the likes.
Typically, step (c) further comprises bleaching along with scouring and cationization of the material by adding 1 to 8 gm/liter of hydrogen peroxide.

Typically, the step (d) comprising loading the cationized dyed material obtained in step (c) and water in the bath followed by heating the bath to raise the temperature in the range of 75°C to 90°C, running the bath for at least 8 to 15 minutes of the residence time and draining the bath after the wash to obtain a washed cationized dyed material.
Typically, the step (d) comprises loading the cationized dyed material obtained in step (c) and water in the bath followed by heating the bath to raise the temperature to 80°C, running the bath for at least 10 minutes of the residence time and draining the bath after the wash to obtain the washed cationized dyed material.
Typically, the material to water ratio in step (d) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

Typically, the step (e) of neutralization is carried out by loading the washed cationized dyed material obtained in step (d) and water followed by adding acid to the bath to adjust the pH of the bath in the range of 4 to 6, running the material for at least 5 to 15 minutes of the residence time while maintaining the pH in the range of 4 to 6 and draining the bath to obtain a neutralized cationized dyed material.
The acid used in the neutralization in step (e) is selected from acetic acid, citric acid, formic acid and the likes.
Typically, the step (e) of neutralization is carried out by loading the washed cationized dyed material obtained in step (d) and water followed by adding acetic acid solution (33%) to the bath to adjust the pH of the bath in the range of 4.5 to 5.5, running the material for at least 10 minutes of the residence time while maintaining the pH in the range of 4.5 to 5.5 and draining the bath to obtain the neutralized cationized dyed material.
Typically, the material to water ratio in step (e) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

Typically, the step (f) of cotton dyeing comprises loading the neutralized cationized dyed material obtained in step (e) and water in the bath, raising the temperature of the dye bath to 50° C, dosing the reactive dyes along with auxiliaries at 50° C, adding first alkali followed by addition of second alkali to adjust the pH of the bath in the range of 9 to 12.5, raising the temperature of the dye bath from 50° C to 60° C at the rate of 1.5°C/minute followed by running the material in the bath for at least 25 to 60 minutes of the residence time to dye cotton fiber component of the material and draining the bath to obtain a dyed material.
Typically, the reactive dyes used are selected from ME and HE class of reactive dyes. The dyes are used either alone or in combination depending upon the desired shade. For example to achieve black color, Corafix yellow ECO+, Corafix red ECo+, and Corafix Black GDE may be used in a specific proportion.
Typically, the weak alkali used in step (f) is selected from sodium bicarbonate and the likes. The strong alkali used is selected from sodium hydroxide, potassium hydroxide and the likes.
Typically, the step (f) of cotton dyeing comprises loading the neutralized cationized dyed material obtained in step (e) and water in the bath, adding auxiliaries consisting of lubricating agents, dye bath conditioners and buffers in the dye bath, raising the temperature of the dye bath to 50° C, dosing the reactive dyes at 50° C over 20 minutes, running the material in the bath for at least 20 minutes of the residence time, adding first alkali of sodium carbonate over 20 minutes followed by addition of second alkali of sodium hydroxide over 30 minutes to adjust the bath pH in the range of 10.5 to 11.5, raising the temperature of the dye bath from 50° C to 60° C at the rate of 1.5°C/minute followed by running the material in the bath for at least 45 to 55 minutes of the residence time to dye cotton fiber component of the material and draining the bath to obtain the dyed material.
Typically, the auxiliaries used in step (f) are selected from lubricating agents like fatty alcohol ethoxylate such as Dep. ACA B-Liq. and the likes; dye bath conditioners such as Sunsoft LM7, Albatex AB55 and the likes; buffers such as Orgakol TSP, and the likes.
Typically, the material to water ratio in step (f) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

Typically, the step (g) of wash with water comprises loading the dyed material obtained in step (f) and water in the bath, running the bath for at least 5 to 15 minutes of the residence time at the temperature in the range of 25°C to 30°C and draining the bath after treatment to obtain a washed dyed material.
Typically, the step (g) of wash with water comprises loading the dyed material obtained in step (e) and water in the bath, running the bath for at least 10 minutes of the residence time at the temperature of 25° C and draining the bath after treatment to obtain the washed dyed material.
Typically, the material to water ratio in step (g) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.)
The step (g) may be repeated again.

Typically, the step (h) of neutralization comprises loading the washed dyed material obtained in step (g) and water in the bath followed by addition of acid to adjust the pH in the range of 4.5 to 6.5, running the material in the bath for at least 5 to 15 minutes of the residence time while maintaining the pH in the range of 4.5 to 6.5 and draining the bath after the treatment to obtain a neutralized dyed material.
The acid used in the neutralization in step (h) is selected from acetic acid, citric acid, formic acid and the likes.
Typically, the step (h) of neutralization comprises loading the washed dyed material obtained in step (g) and water followed by addition of acetic acid solution (33%) to adjust the pH in the range of 4.5 to 5.5, running the material in the bath for at least 10 minutes of residence time while maintaining the pH in the range of 4.5 to 5.5 and draining the bath upon completion of the neutralization step (h) to obtain the neutralized dyed material.
Typically, the material to water ratio in step (h) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

Typically, the step (i) of treatment with wash off agent comprises loading the neutralized dyed material obtained in step (h) and water in the bath followed by addition of a wash off agent followed by heating the bath to raise the temperature in the range of 80°C to 100°C, running the material in the bath at the maintained temperature for at least 5 to 15 minutes of the residence time and draining the bath to obtain a treated dyed material.
Typically, the wash off agent is selected from acrylic polymeric based washing off agents such as Diakol ECO and the likes.
Typically, the step (i) of treatment with wash off agent comprises loading neutralized dyed material obtained in step (h) and water followed by addition of 2 gm/liter of wash off agent namely Diakol ECO, heating the bath to raise the temperature to 95°C, running the material in the bath at the maintained temperature for at least 15 minutes of the residence time and draining the bath after completion of step (i) to obtain the treated dyed material.
Typically, the material to water ratio in step (i) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

Typically, the step (j) of hot wash comprises loading the treated dyed material obtained in step (i) and water followed by heating the bath to raise the temperature in the range of 80°C to 90°C, running the material in the bath for at least 5 to 15 minutes of the residence time and draining the bath after wash to obtain a washed dyed material.
Typically, the step (j) comprises loading the treated dyed material obtained in step (i) and water followed by heating the bath to raise the temperature to 85°C, running the material in the bath for at least 10 minutes of the residence time and draining the bath after wash to obtain the washed dyed material.
Typically, the material to water ratio in step (j) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

Typically, the step (k) of wash with water comprises loading the washed dyed material obtained in step (j) and water, running the material in the bath for at least 5 to 15 minutes of the residence time at the temperature in the range of 25° C to 30° C and draining the bath upon wash to obtain a dyed material.
Typically, the step (k) comprises loading the washed dyed material obtained in step (j) and water, running the material in the bath for at least 10 minutes of the residence time at 25° C and draining the bath upon wash to obtain the dyed material.
This step (k) may be repeated again.
Optionally, the dyed material is washed with water.

According to the present invention of the cost-effective and the eco-friendly dyeing method for the material of polyester-cotton blends which comprises dyeing the polyester fibre component of the material followed by pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath followed by dyeing the cotton fibre component of the material, reduces
• number of steps to 11;
• 24 to 32 % of fresh water consumption,
• 25 to 32 % of effluent generated and drained,
• 8 to 14% of the total time consumption,
• 7 to 18 % of cost of dyeing; and
• eliminates step of dye-fixing and use of glauber's salt;
thereby making the invention cost-effective and eco-friendly.

DETAILED DESCRIPTION OF THE INVENTION:
The terms “a,” “an,” “the” and similar referents used in the context of describing the invention following claims are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it was individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intend for the invention to be practiced otherwise than specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the below-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
Specific embodiments disclosed herein can be further limited in the claims using consisting of or/and consisting essentially of language. When used in the claims, whether as filed or added per amendment, the transition term “consisting of excludes any element, step, or ingredient not specified in the claims. The transition term “consisting essentially of limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic(s). Embodiments of the invention so claimed are inherently or expressly described and enabled herein.
As used herein, the term "material" refers to fabric or fiber or yarn. The fabric or yarn is either woven or knitted or felted fabric/yarn made up of blends of the fibers of cotton with polyester.
As used herein, the terms "polyester-cotton blends" refers to fabric or fiber or yarn of cotton and polyester blending in different proportions as per the need. The fabric or yarn is either woven or knitted or felted fabric/yarn made up of blending the cotton fibers and polyester fibers.
As used herein, the term "cationizing agent" refers to any cationizing agent which introduces the cationic group on the surface of the cellulosic material that renders the material's cationic property and increases their affinity for anionic dyes.
As used herein, the term "weight percent (wt. %)" when used without qualification, typically refers to the weight percent of a particular solid component as compared with all solid components present in the reaction mixture.

DETAILED DESCRIPTION OF THE EMBODIMENTS:
In the following description, the embodiments are described in sufficient details to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical and other changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. The detailed description that follows begins with a definition section followed by a description of various embodiments of the invention. A series of examples are presented later followed by a brief conclusion.
Cotton cellulose material has excellent properties such as good moisture absorbency, comfortable to wear, and easy to dye. These properties makes cotton textiles very popular amongst us. The cotton is composed of 90-96% cellulose based on the weight of the fibers and 4% to 10% non-cellulosic components. The cotton fibers are naturally yellowish or brown in color.
The material used in the present invention is polyester-cotton blend in the ratio of 20:80 to 80:20. The fabric is having density of = 50 gsm and =1000 gsm.
The cotton fiber component being hydrophilic has affinity towards reactive dyes and the polyester fiber component being hydrophobic has affinity towards disperse dye. Generally, the dyeing of cotton is carried out in alkaline pH and at lower temperature range of 60°C to 80°C in the presence of electrolyte/salt and dyeing of the polyester is carried out at acidic pH and at higher temperature range of 100°C to 135°C respectively. Due to this, the conventional process is carried out in two separate baths. The polyester dyeing is followed by alkali reduction clearing to improve fastness.
It is well known that reduction clearing process is a vital part of polyester blend dyeing especially for medium to dark colors. In the case of dyeing of polyester-cotton blend, dyeing process comprehends the sequence e.g. pre-treatment including scouring and cationization, polyester part dyeing, reduction clearing and finally cotton part dyeing along with other mandatory steps including hot boiling, neutralization, washing with water, hot wash, treatment with wash off agent, dye-fixing, etc..

The conventional method of dyeing polyester-cotton blends used commercially consist of the following steps:
1. Hot Boiling: The bath is loaded with a polyester-cotton blend and water along with auxiliaries comprising 0.5 gm/liter of Dikapal AP Liquid, 1 gm/liter of Exo Wet ES and 0.7 gm/liter of Exsosperse HC. The bath is heated to 90°C and the material is run in the bath for 10 minutes. The bath is cooled to 78°C subsequently the bath is drained after the treatment to obtain a treated material;
2. Polyester Dyeing: The bath is loaded with the treated material obtained in step (1) and water along with auxiliaries consisting of 1 gm/liter of Dep. ACA B-Liq., 0.5 gm/liter of sodium acetate, 0.7 gm/liter of Sunsoft LM7C, 1.3 gm/liter of Levocol CWS and 1.0 gm/liter of acetic acid followed by heating the bath to 60°C. Bath pH is checked and maintained between 4.5 to 5.5. After pH confirmation, dispersed polyester dyes consisting of 0.002% of Coralene Brilliant Red HP3BSand 2.25 % of Coralene Black RLS are added to the bath over 20 minutes. The bath is heated to 90°C at the rate of 2.5°C/minute followed by heating the bath from 90°C to 130°C at the rate of 1.5°C/minute. When temperature of the bath reaches to 130°C, the material is run in the bath for 40 minutes. Further the bath is cooled to 90°C at the rate of 1.5°C/minute followed by cooling the bath from 74°C at the rate of 2.5°C /minute. A dyed material so obtained is tested for the shade of polyester dyed portion after carbonization treatment. Upon matching of the carbonized cutting shade with carbonized standard cutting shade, the bath is drained to obtain a dyed material;
3. Reduction clearing: The polyester-cotton blend upon polyester fiber component dyeing is subjected to reduction clearing which comprises the steps of: The dyed material obtained in step (2) and water is loaded in the bath. 2 gm/liter of sodium hydroxide and 2 gm/liter of sodium dithionite are added to the bath. The bath is heated to 60°C followed by heating the bath to raise the temperature to 80°C. The bath is run for 20 minutes followed by cooling the bath to 74°C to remove unused disperse dye. The bath is drained after the treatment to obtain a treated dyed material;
4. Reduction clearing: The treated dyed material so obtained in step (3) is again subjected to reduction clearing according to step (3) to obtain a treated dyed material.
5. Hot wash: The treated dyed material obtained in step (4) is subjected to hot wash by loading the material obtained in step (4) and water, running the material in water at 80°C for 10 minutes in the bath and draining the bath after wash to obtain a washed dyed material;
6. Neutralization: The washed dyed material obtained in step (5) is subjected to neutralization which comprises the steps of : The bath is loaded with the material obtained in step (5) and water followed by adding acetic acid solution (33%) to adjust the bath pH between 5 to 6, running the dyed material in the bath for 10 minutes by maintaining the pH of the bath between 5 to 6 and the bath is drained after completion of neutralization to obtain a neutralized dyed material;
7. Cotton Dyeing: The bath is loaded with the neutralized dyed material obtained in step (6) and water along with auxiliaries consisting of 1 gm/liter of Dep. ACA B-Liq., 0.5 gm/liter of Albatex AB55, and 0.5 gm/liter of Orgakol TSP. The bath is heated to 50° C. The dyes consisting of 0.40 % of Corafix Yellow ECO+, 0.13 % of Corafix Red ECO+ and 7.83 % of Corafix Black GDE are added to the bath over 20 minutes at 50° C. The material is run in the bath for at least 10 minutes. 80 gm/liter of gluaber's salt is added in the bath over 40 minutes. The bath is run for another 20 minutes. 6 gm/liter of sodium carbonate as first alkali is added in the bath over period of 20 minutes followed by running the bath for 5 minutes. The second alkali, 1.9 gm/lit of caustic (NaOH) is added in the bath over 30 minutes followed by running the bath for at least 5 minutes to adjust the bath pH in the range of 9 to 10. The temperature of the dye bath is increased from 50°C to 60°C followed by running the material in the bath for at least 50 minutes at 60° C to dye cotton fiber component of the material. The depth of the shade of the dyed material is checked by taking small window cutting. The bath is drained after dyeing to obtain a dyed material;
8. Wash with water: The dyed material obtained in step (7) is subjected to wash by running the material in the bath comprising water for 10 minutes at 25°C and the bath is drained after wash to obtain a washed dyed material;
9. Wash with water: The washed dyed material obtained in step (8) is again subjected to wash by running the material in the bath comprising water for 10 minutes at 25°C and the bath is drained after wash to obtain a washed dyed material;
10. Neutralization: The washed dyed material obtained in step (9) is subjected to neutralization where the bath is loaded with the material obtained in step (9) and water followed by adding acetic acid solution (33%) to adjust the bath pH in the range of 4.5 to 5.5, running the dyed material in the bath for 10 minutes by maintaining bath pH in the range of 4.5 to 5.5 and the bath is drained after neutralization to obtain a neutralized dyed material;
11. Treatment with wash off agent: The neutralized dyed material obtained in step (10) and water are loaded in the bath. To this bath, 2 gm/liter of Diakol ECO is added. The bath is heated to raise the temperature to 85°C. The material is run in the bath for 20 minutes at the maintained temperature and the bath is drained after completion of the treatment to obtain a treated dyed material.
12. Hot wash: The treated dyed material obtained in step (11) is subjected to hot wash by loading the material and water in the bath followed by heating the bath to raise the temperature to 85°C, running the material in the bath for 10 minutes and the bath is drained after wash to obtain a washed dyed material;
13. Hot wash: The washed dyed material obtained in step (12) is once again subjected to hot wash according to step (12) and the bath is drained after wash to obtain a washed dyed material;
14. Wash with water: The washed dyed material obtained in step (13) is subjected to wash with water by loading the material and water in the bath followed by running the material in the water at 25°C for 10 minutes and the bath is drained after wash to obtain a washed dyed material;
15. Wash with water: The dyed material obtained in step (14) is once again subjected to wash with water according to step (14) and the bath is drained after wash to obtain a washed dyed material; and
16. Dye-fixing: The washed dyed material obtained in step (15) is subjected to dye-fixing by loading the material obtained in step (15) and water in the bath, adding 1.2 gm/liter of Alwafix WFF in the bath followed by running the material in the bath for 10 minutes and the bath is drained after treatment to obtain a dyed material.

According to the conventional dyeing method by using globular salt, to dye 240 Kg of Cotton/polyester blend; results into
• number of steps: 16
• the cost of the dyeing is around Rs. 36627/-;
• the total water consumption is around 14760 Liters;
• the total time consumption is around more than 10 Hours 36 minutes;
• the effluent generated is around 14040 Liters; and
• the total salt consumption is around 115.2 Kg.

There is another conventional method of dyeing a polyester-cotton blends material by cationization consisting of the following steps:
i. subjecting the polyester-cotton blend material to hot boiling in the presence of auxiliaries to obtain a treated material;
ii. subjecting the treated material obtained in step (i) to a pre-treatment comprising scouring and cationization in the presence of alkali to adjust the pH in the range of 9 to 10 to obtain a cationized material;
iii. subjecting the cationized material obtained in step (ii) to hot wash treatment to obtain a washed cationized material;
iv. subjecting the washed cationized material obtained in step (iii) to neutralization treatment to obtain a neutralized cationized material;
v. subjecting the neutralized cationized material obtained in step (iv) to a polyester dyeing in a bath comprising disperse dyes and auxiliaries to dye a polyester fiber component of the material to obtain a cationized dyed material;
vi. subjecting the cationized dyed material obtained in step (v) to a reduction clearing to obtain a treated cationized dyed material;
vii. subjecting the treated cationized dyed material obtained in step (vi) to hot wash treatment to obtain a washed cationized dyed material;
viii. subjecting the washed cationized dyed material obtained in step (vii) to neutralization treatment to obtain a neutralized cationized dyed material;
ix. subjecting the neutralized cationized dyed material obtained in step (viii) to wash with water treatment to obtain a washed cationized dyed material;
x. subjecting the washed cationized dyed material obtained in step (ix) to cotton dyeing in a bath comprising reactive dyes, auxiliaries, and alkali to dye a cotton fiber component of the cationized dyed material to obtain a dyed material;
xi. subjecting the dyed material obtained in step (x) to wash with water treatment to obtain a washed dyed material;
xii. subjecting the washed dyed material obtained in step (xi) to neutralization treatment to obtain a neutralized dyed material;
xiii. subjecting the neutralized dyed material obtained in step (xii) to treatment with wash off agent to obtain a treated dyed material;
xiv. subjecting the treated dyed material obtained in step (xiii) to hot wash to obtain a washed dyed material; and
xv. subjecting the washed dyed material obtained in step (xiv) to wash with water to obtain a dyed material;
The dyed material so obtained by the above-mentioned conventional method has color fastness properties to wash as well as rubbing and shade of the color as desired by the requirement.

The above-referred conventional the method of dyeing for 240 kg of the material of polyester-cotton blends results into
• the number of steps: 15;
• the cost of the dyeing is around 38768;
• the total water consumption is around 13872 Liters;
• the total time consumption is around 10 Hours 42 minutes; and
• the effluent generated is around 13150 Liters.

The main objective of the present invention is to simultaneously carry out the pre-treatment consisting of scouring and cationization and reduction clearing steps in a single bath as well as eliminate the use of electrolyte/salt and dye-fixing agent, thereby leading to reduction in number of steps of dyeing, water consumption, effluent generation, chemicals consumption, cost of dyeing, energy, manpower, etc and making the method of dyeing of the invention cost-effective and eco-friendly.

The presently claimed invention is directed to a cost-effective and eco-friendly method of dyeing a polyester-cotton blends material.
In the presently claimed invention, the method consisting of:
a) subjecting the material to hot boiling in the presence of auxiliaries to obtain a treated material;
b) subjecting the treated material obtained in step (a) to polyester dyeing in the bath comprising disperse dyes and auxiliaries to dye a polyester fiber component of the material to obtain a dyed material;
c) subjecting the dyed material obtained in step (b) to a pre-treatment consisting of scouring and cationization, with simultaneous reduction clearing in a single bath to obtain a cationized dyed material;
d) subjecting the cationized dyed material obtained in step (c) to hot wash to obtain a washed cationized dyed material;
e) subjecting the washed cationized dyed material obtained in step (d) to neutralization to obtain a neutralized cationized dyed material;
f) subjecting the neutralized cationized dyed material obtained in step (e) to cotton dyeing in the bath comprising reactive dyes, auxiliaries, and alkali to dye a cotton fiber component of the cationized dyed material to obtain a dyed material;
g) subjecting the dyed material obtained in step (f) to wash with water to obtain a washed dyed material;
h) subjecting the washed dyed material obtained in step (g) to neutralization to obtain a neutralized dyed material;
i) subjecting the neutralized dyed material obtained in step (h) to treatment with wash off agent to obtain a treated dyed material;
j) subjecting the treated dyed material obtained in step (i) to hot wash to obtain a washed dyed material; and
k) subjecting the washed dyed material obtained in step (k) to wash with water to obtain a dyed material;
the dyed material has good color fastness to wash and to both wet rubbing and dry rubbing properties without sacrificing the shade of the dyed color;
said method reduces water consumption, effluent generation, steps of dyeing, power consumption, energy consumption, waste disposal, dyeing cost and pollution; thereby making the method cost-effective and eco-friendly.

In one of the embodiments of the invention, the step (a) of hot boiling comprises the steps of: The bath is loaded with polyester-cotton blend material (fabric) and water. Auxiliaries consisting of wetting, dispersing agent and lubricating / anti-creasing agent are added in the bath. The bath is heated to raise the temperature in the range of 80°C to 95°C. The material is run in the bath for at least 5 to 20 minutes of a residence time followed by cooling down the bath to 78°C. Finally, the bath is drained to obtain a treated material.
The temperature of the bath is raised to 90°C in step (a) to carry out the hot boiling treatment.
The material to water ratio in step (a) is 1:5 to 8 (wt./vol.), preferably 1:6 (wt./vol.).
The lubricating agent used in step (a) is selected from low foaming anionic or non-ionic lubricating agents like C12 to C14 fatty alcohol ethoxylate, EO/PO adducts, phosphate ester such as Dikapal AP Liquid and the likes.
The dispersing agent used in step (a) is selected from polymeric dispersing agent such as Exhosperse HC and the likes.
The lubricating/anti-creasing agent used in step (a) is selected from Albafluid HGL polymeric blends of surfactant.
The wetting agent used in step (a) is selected from non-ionic wetting agent such as Exowet ES and the likes.
In a preferred embodiment of the invention, the hot boiling step (a) comprises: The bath is loaded with material and water in a ratio of 1:5 to 8 (wt./vol.). 1 gm/liter of wetting agent, 0.7 gm/liter of dispersing agent and 0.5 gm/liter of lubricating agent are added in the bath. The bath is heated to raise a temperature to 90°C. The material is run in the bath for at least 10 minutes of the residence time. The bath is cooled down to 78°C. The bath is drained after the treatment to obtain a treated material.

In one of the embodiments of the invention, the step (b) of the polyester dyeing comprises: The bath is loaded with the treated material obtained in step (a) and water. The disperse dyes along with auxiliaries are added in the bath. The bath pH is maintained in the range of 4 to 6. The bath is heated to raise the temperature to 60°C. The bath is further heated to raise the temperature to 90°C then to 110°C finally to 135°C. The material is run in the bath for at least 25 to 50 minutes of the residence time to dye polyester fiber component of the material. The bath is cooled to 74°C and the bath is finally drained to obtain a dyed material.
In the preferred embodiment of the invention, the step (b) of the polyester dyeing comprises: The bath is loaded with the treated material obtained in step (a) and water. The auxiliaries are added in the dye bath. The bath pH is checked and maintained in the range of 4.5 to 5.5. The bath is heated to raise the temperature to 60°C. The disperse dyes are added in the bath. The bath is heated to raise the temperature of the bath to 90° C at the rate of 3°C/minute followed by raising the temperature of the bath from 90°C to 110°C at the rate of 2.5°C/minute finally raising the temperature of the bath from 110°C to 130°C at the rate of 1.5°C/minute. The material is run in the bath for at least 25 to 45 minutes of the residence time to dye polyester fiber component of the material. The dye bath is cooled from 130°C to 110°C at the rate of 1.5°C/minute followed by cooling the bath from 110°C to 90°C at the rate of 2.5°C/minute finally cooling the bath from 90°C to 74°C at the rate of 3°C/minute. The bath is drained at the end of step (b) to obtain the dyed material.
The material to water ratio in step (b) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).
The disperse dyes used in step (b) are selected from anthraquinonoid and azo-based disperse dyes. These dyes are also used either alone or in combination depending upon the desired shade. For example to achieve black color, Coralene brilliant red HP3BS and Coralene black RLS may be used in a specific proportion.
Typically, the auxiliaries are selected from lubricating agents like fatty alcohol ethoxylate such as Dep. ACA B-Liq. and the likes; dye bath conditioners such as Sunsoft LM7, Albatex AB55 and the likes; dispersing agents such as Levocol CWS and the likes; pH regulators such as acetic acid and the likes; buffers such as sodium acetate, Orgakol TSP, and the likes.
In the step (b), the bath is loaded with the treated material obtained in step (a) and water. The auxiliaries consisting of 1 gm/liter of Dep. ACA B-Liq., 0.5 gm/liter of sodium acetate, 0.7 gm/liter of Sunsoft LM7, 1.3 gm/liter of Levocol CWS and 1.0 gm/liter of acetic acid are added in the bath. The bath pH is checked and it is maintained in the range of 4.5 to 5.5. The bath is heated to 60°C. After pH confirmation, the dispersed polyester dyes consisting of 0.002 % of Coralene Brilliant Red HP3BS and 2.25 % of Coralene Black RLS are added to the bath over 20 minutes. The bath is heated to 90°C at the rate of 3°C/minute followed by heating the bath to raise the temperature from 90°C to 110°C at the rate of 2.5°C/minute finally heating the bath to raise the temperature of the bath from 110°C to 130°C at the rate of 1.5°C/minute. When temperature of the bath reaches to 130°C, the material is run in the bath for at least 25 to 45 minutes of the residence time. Further the bath is cooled to 110°C at the rate of 1.5°C/minute followed by cooling the bath from 110°C to 90°C at the rate of 2.5°C /minute finally cooling the bath from 90°C to 74°C at the rate of 3°C /minute. Finally, the material is tested for a shade of polyester dyed portion after carbonization treatment. Upon matching of the carbonized cutting shade with the carbonized standard cutting shade, the bath is drained;
Scouring treatment removes components including wax, pectin, protein, etc. and improves bleaching and acceptability of dye by the material. Scouring comprises alkali treatment to material mostly at higher temperature, particularly temperature above 60°C. Scouring, in common practice, involves boiling the material in sodium hydroxide (2 to 3 gm/liter and pH in the range of 10 to 14) in the presence of surfactants or wetting agents for about 30 to 60 minutes. Upon completion of scouring process, it is washed with plentiful amount of water. Scouring helps to improve water absorbency and the appearance of the material becomes clean and soft.
Particularly, the wetting agents or surfactants used are selected from the group consisting of low foaming alkali stable wetting agents or surfactants including nonionic alcohol, EO/PO adducts, alkyl end capped phenol and the likes.
However, natural color of cotton material is not removed in the scouring process. To meet the whiteness requirement, the material is subjected to bleaching. Hydrogen peroxide is an environmentally safe bleaching agent for the material. The bleaching of the material is carried out by treating it with hydrogen peroxide in an alkaline medium, stabilizer and either at high temperatures, particularly at 90°C to 110°C or at a long dwell time (approximately 30 to 60 minutes). Approximately 2 to 3 gm/liter of caustic soda is used in bleaching to adjust the bath pH in the range of 10.5 to 10.8. Upon completion of the bleaching process, it is first neutralized and then washed with plentiful amount of water. The bleaching is optional and need to be carried out only when there is whiteness requirement.
In one of the embodiments of the invention, the step (c) comprises pre-treatment consisting of scouring and cationization with simultaneous and reduction clearing in a single bath, wherein the step (c) comprising the steps of: Water and the dyed material obtained in step (b) are loaded in the bath. Auxiliaries are added to the bath and the bath is heated to raise the temperature to 60°C. The alkali is added to the bath to adjust the bath pH in the range of 10 to 14. The bath is run for at least 5 to 15 minutes. 10 to 90 gm/liter of cationizing agent is added to the bath followed by running the bath for at least 5 to 15 minutes. The bath is heated to raise the temperature of the bath to 85°C at the rate of 3°C/minute followed by running the material in bath for at least 25 to 60 minutes of the residence time. The bath is cooled to 74°C. The reducing agent is added to bath followed by heating the bath to raise the temperature of the bath to 80°C. The material is run in the bath for at least 15 to 30 minutes of the residence time. The bath is cooled to 74°C. The bath is subsequently drained to obtain a cationized dyed material.
Typically, the material to water ratio in step (c) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).
Typically, the alkali used is selected from sodium hydroxide, potassium hydroxide and the likes.
Typically auxiliaries used in step (c) are selected from polymeric dispersing agents such as Exhosperse HC and the likes, wetting agents like non-ionic wetting agents such as Exowet ES and the likes, anionic and nonionic lubricating agents like fatty alcohols ethoxylates such as Dep. ACA B-Liq and the likes.
The cationizing agent used in step (c) is selected from 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMAC).
Typically, the reducing agent used in step (c) is selected from sodium dithionite and the likes.
Typically, the step (c) further comprises bleaching along with scouring and cationization of the material by adding 1 to 8 gm/liter of hydrogen peroxide.
Particularly, the stabilizer used is selected from the group consisting of organic stabilizers such as pentasodium diethylenetriamine penta acetic acid, amino tri-(methylene phosphonic acid), saccharide-acrylate copolymers with carboxylic acids and the likes.
In the preferred embodiment of the invention, the step (c) comprising of the steps of: Water and the dyed material obtained in step (b) are added in the bath. Auxiliaries including 0.5 gm/liter of Dep. ACA B-Liq. and 0.7 gm/liter of Exsosperse HC are added to the bath. The bath is heated to raise the temperature to 60°C. 1/4th on the basis cationizing agent, dosage of sodium hydroxide is added to the bath to adjust the bath pH in the range of 11.5 to 12.5. The material is run in the bath for at least 10 minutes of the residence time. 20 to 80 gm/liter of cationizing agent is added to the bath followed by running the dyed material in the bath for at least 10 minutes of the residence time. The bath is heated to raise the temperature to 85°C at the rate of 3°C/minute followed by running the material in bath for at least 45 minutes of the residence time. The bath is cooled to 74°C. 3 gm/liter of reducing agent, sodium dithionite, is added followed by heating the bath to raise the temperature to 80°C. The material is run in the bath for at least 20 minutes of the residence time. The bath is cooled to 74°C. The bath is subsequently drained to obtain the cationized dyed material.

In one of the embodiments of the invention, the step (d) of the hot wash comprises: The cationized dyed material obtained in step (c) and water are loaded in the bath. The bath is heated to raise temperature in the range of 75°C to 90°C. The material is run in the bath for at least 8 to 15 minutes of the residence time. Finally the bath is drained after wash to obtain a washed cationized dyed material.
In a preferred embodiment of the invention, the step (d) comprises the steps of: The cationized dyed material obtained in step (c) and water are loaded in the bath. The bath is heated to raise the temperature to 80°C. The material is run in the bath for at least 10 minutes of the residence time and the bath is drained after wash to obtain the washed cationized dyed material.
Typically, the material to water ratio in step (d) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

In one of the embodiments of the invention, the step (e) comprises: The bath is loaded with the washed cationized dyed material obtained in step (d) and water. The acid is added to the bath to adjust the pH in the range of 4 to 6. The cationized dyed material is run in the bath for at least 5 to 15 minutes of the residence time while maintaining the pH in the range of 4 to 6. The bath is drained upon completion of the neutralization and a neutralized cationized blend material is obtained.
The acid used in the neutralization in step (e) is selected from acetic acid, citric acid, formic acid and the like.
In a preferred embodiment of the invention, the step (e) comprises: The bath is loaded with the neutralized cationized dyed material obtained in step (d) and water. Acetic acid solution (33%) is added to the bath to adjust the pH in the range of 4.5 to 5.5. The neutralized cationized dyed material is run in the bath for at least 10 minutes of the residence time while maintaining the pH in the range of 4.5 to 5.5. The bath is drained after completion of neutralization and the neutralized cationized blend material is obtained.
Typically, the material to water ratio in step (e) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

In one of the embodiments of the invention, the step (f) of the cotton dyeing comprises: The neutralized cationized dyed material obtained in step (e) and water are loaded in the bath. The bath is heated to raise the temperature to 50° C. The reactive dyes along with the auxiliaries are added to the bath at 50° C. The first alkali is added to the bath followed by addition of second alkali to adjust the pH of the bath in the range of 9 to 12.5. The bath is heated to raise the temperature of the bath from 50° C to 60° C at the rate of 1.5°C /minute. The dyed cationized material is run in the bath for at least 25 to 60 minutes of the residence time to dye cotton fiber component of the material and the bath is drained at the end of step (g) to obtain a dyed material.
Typically, the reactive dyes used are selected from ME and HE class of reactive dyes. The dyes are used either alone or in combination depending upon the desired shade. For example to achieve black color Corafix yellow ECO+, Corafix red ECo+, and Corafix Black GDE may be used in a specific proportion.
Typically, the weak alkali used is selected from sodium bicarbonate and the likes. The strong alkali used is selected from sodium hydroxide, potassium hydroxide and the likes.
In a preferred embodiment of the invention, the step (f) of the cotton dyeing comprises: The bath is loaded with neutralized cationized dyed material obtained in step (e) and water. Auxiliaries consisting of lubricating agents, dye bath conditioners and buffers are added to the bath. The bath is heated to raise the temperature to 50° C. The reactive dyes are added to the bath over at least 20 minutes at 50°C. The bath is run for at least 20 minutes. The first alkali of sodium bicarbonate is added in the bath over 20 minutes followed by addition of second alkali of sodium hydroxide over 30 minutes to adjust the pH in the range of 10.5 to 11.5. The bath is run for 5 minutes and further it is heated to raise the temperature from 50°C to 60°C at the rate of 1.5°C /minute. The material is run in the bath for at least 45 to 55 minutes of the residence time to dye cotton fiber component of the material. A depth of the shade of the dyed material is checked by taking small window cutting. The bath is drained after dyeing to obtain a dyed material.
The auxiliaries used in the step (f) are selected from lubricating agents like fatty alcohols ethoxylates such as Dep. ACA B-Liq. and the likes; dye bath conditioners such as Sunsoft LM7, Albatex AB55 and the likes; buffers such as Orgakol TSP, and the likes.
The material to water ratio in step (f) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

In one of the embodiments of the invention, the step (g) of wash with water comprises: The dyed material obtained in step (f) and water are loaded in the bath. The material is run in the bath for at least 5 to 15 minutes of the residence time at the temperature in the range of 25°C to 30°C and the bath is drained after the treatment to obtain a dyed material.
In a preferred embodiment of the invention, the step (g) comprises: The dyed material obtained in step (f) and water are loaded in the bath. The material is run in the bath for at least 10 minutes of the residence time at temperature in the range of 25° C. The bath is drained after the treatment to obtain the dyed material.
This step (g) may be repeated depending upon the requirement.
Typically, the material to water ratio in step (g) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

In one of the embodiments of the invention, the step (h) of neutralization comprises: The dyed material obtained in step (g) and water are loaded in the bath. The acid is added to the bath to adjust the pH in the range of 4.5 to 6.5. The material is run in the bath for at least 5 to 15 minutes of the residence time while maintaining the pH in the range of 4.5 to 6.5. The bath is drained after the treatment to obtain a neutralized dyed material.
The acid used in the neutralization in step (h) is selected from acetic acid, citric acid, formic acid and the likes.
In a preferred embodiment of the invention, the step (h) of neutralization consisting of: The bath is loaded with the dyed material obtained in step (g) and water. The acetic acid solution (33%) is added to the bath to adjust the pH in the range of 4.5 to 5.5. The dyed material is run in the bath for at least 10 minutes of the residence time while maintaining the pH in the range of 4.5 to 5.5. The bath is drained upon completion of the neutralization step (h) to obtain the neutralized dyed material.
Typically, the material to water ratio in step (h) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

In one of the embodiments of the invention, the step (i) of treatment with wash off agent comprises: The neutralized dyed material obtained in step (h) and water are loaded in the bath. A wash off agent is added in the bath. The bath is heated to raise the temperature in the range of 80°C to 100°C. The material is run in the bath at the maintained temperature for at least 5 to 15 minutes of the residence time. The bath is drained after the treatment to obtain a treated dyed material.
The wash off agent used in the step (i) is selected from acrylic polymeric based washing off agents such as Diakol ECO and the likes.
In a preferred embodiment of the invention, the step (i) of treatment with wash off agent comprises: The neutralized dyed material obtained in step (h) and water are loaded in the bath. 2 gm/liter of Diakol ECO (wash off agent) is added to the bath and the bath is heated to raise the temperature to 95°C. The material is run in the bath at the maintained temperature for at least 15 minutes of the residence time. The bath is drained after completion of the step (i) to obtain the treated dyed material.
Typically, the material to water ratio in step (i) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

In one of the embodiments of the invention, the step (j) of treatment of hot wash comprises: The treated dyed material obtained in step (i) and water are loaded in the bath. The bath is heated to raise the temperature in the range of 80°C to 90°C. The material is run in the bath for at least 5 to 15 minutes of the residence time. The bath is drained after wash to obtain a washed dyed material.
In a preferred embodiment of the invention, the step (j) of treatment of hot wash comprises: The treated dyed material obtained in step (i) and water are loaded in the bath. The bath is heated to raise the temperature to 85°C. The material is run in the bath for at least 10 minutes of the residence time. The bath is drained after wash to obtain the washed dyed material.
Typically, the material to water ratio in step (j) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).

In one of the embodiments of the invention, the step (k) of wash with water comprises: The washed dyed material obtained in step (j) and water are added in the bath. The material is run in the bath for at least 5 to 15 minutes of the residence time at the temperature in the range of 25°C to 30° C. The bath is drained upon wash to obtain a dyed material.
In the preferred embodiment of the invention, the step (k) of wash with water comprises: The dyed material obtained in step (k) and water are loaded in the bath. The material is run in the bath for at least 10 minutes of the residence time at 25°C. The bath is drained upon wash to obtain the dyed material.
Typically, the material to water ratio in step (k) is 1:3 to 5 (wt./vol.), preferably 1:3.7 (wt./vol.).
This step (k) may be repeated again.
Optionally, the dye material obtained in step (k) is additionally washed with water.

According to the present invention of the cost-effective and the eco-friendly dyeing method for the material of polyester-cotton blends which comprises dyeing the polyester fibre component of the material followed by pre-treatment consisting scouring and cationization with simultaneous reduction clearing in a single bath followed by dyeing the cotton fibre component of the material; the method results into
• the number of steps: 11;
• the cost of the dyeing is around Rs. 33076.3;
• the total water consumption is around 10320 Liters;
• the total time consumption is around more than 9 Hours 30 minutes;
• the effluent generated is around 9600 Liters; and
• eliminates the chemicals like dye-fixer and glauber's salt.
Against conventional dyeing method of polyester-cotton blend material, the presently claimed invention reduced the followings:
• number of steps to 11,
• 24 to 32 % of fresh water consumption,
• 25 to 32 % of effluent generated and drained,
• 8 to 14% of the total time consumption,
• 7 to 18 % of cost of dyeing; and
• eliminates sodium sulfate decahydrate, glauber's salt.

Thus, the method of single bath dyeing of presently claimed invention is cost-effective and eco-friendly.
The presently claimed invention may reduce effluent generation further by recycling the residual pre-treatment baths remained in step (c) in a subsequent pre-treatment step (c).
The presently claimed invention intend to eliminate the use of two separate baths i.e. one for pre-treatment consisting of scouring and cationization and second for alkaline reduction clearing and also to eliminate the use of glauber's salt which leads to pollution and increased TDS.
In the presently claimed invention, experimental conditions used in and quantities of the raw materials used in the pre-treatment, the dyeing and the acid reduction clearing are optimized after examining the material properties including whiteness, water absorbance, diffusion time, capillary effect, surface morphology, and thermal properties, as well as dye fixation, color yield, and color fastness properties.
The dyed polyester-cotton blend materials A, B and C prepared according to the conventional method using the glauber's salt, another conventional method of dyeing a polyester-cotton blends material by cationization and according to the method of the present invention respectively are tested for the fastness properties i.e. color fastness to wash and color fastness to rubbing.
The test of color fastness to wash is carried out by ISO 105-C06: A2S while that of the dry and wet rubbing fastness properties is carried out by ISO 105-x12.
Surface smoothness is one of the important qualities and requirements imposed by the consumer. As clothing remains next to human skin, it is very sensitive issue to ensure this quality properly. The surface smoothness of the blend material is scrutinized manually. The surface of the dyed material according to the invention is found to be satisfactorily fine with no mentionable changes.
Color fastness to wash:
The color fastness properties to wash of dyed fabric samples A, B and C are tested and compared with each other. The rating of color staining to cotton for the dyed materials A and B is being rated 4. On the other hand, unpredictably the color staining to cotton for the dyed material C is rated 5. Analysis of the color fastness to wash results of all three materials are illustrated in table 1.
TABLE 1
Rating of color fastness properties to wash properties
Samples Staining to Wash Fastness Rating
Polyester-cotton blend of sample A Cotton 4
Nylon 4
Polyester 4
Acrylic 4
Wool 4
Polyester-cotton blend of sample B Cotton 4
Nylon 4
Polyester 4
Acrylic 4
Wool 4
Polyester-cotton blend of sample C Cotton 5
Nylon 4 to 5
Polyester 4 to 5
Acrylic 5
Wool 5

Color fastness to rubbing:
The color fastness properties to both dry and wet rubbing of dyed fabric samples A, B and C are tested and compared with each other. The ratings of color staining in this regard were interestingly found 5 and 3 for the sample B in case of dry and wet rubbing respectively. The results of color fastness to both dry and wet rubbing for the samples A to C are depicted in Table 2.
TABLE 2
Rating of color fastness to both dry and wet rubbing properties

Samples Staining to Dry Rubbing Wet Rubbing
Polyester-cotton blend of sample A Standard rubbing cloth
Cotton
Cotton 4 2 to 3
Polyester-cotton blend of sample B 4 2 to 3
Polyester-cotton blend of sample C 5 3

Thus, the present invention improves color fastness properties of dyed polyester-cotton blend.
The present invention is illustrated by the following example, which is not intended to limit the effective scope of the invention.

Reference Example 1:
Conventional method of dyeing of polyester-cotton blend material (without cationization and with Glauber's Salt)
The polyester-cotton blend (80:20) Knit PC Fleece construction having 270-280 gsm (SAMPLE "A") was used herein.
1. Grey Boiling: The material (240 Kg) was loaded in the bath. The bath was filled up with 1440 liters of water and the auxiliaries including Exhosperse HC (0.7 gm/liter), Exowet ES (1 gm/liter) and Dep. ACA B-Liq. (0.5 gm/liter) were added in the bath. The temperature of the bath was raised to 90°C and the material was run in the bath for 10 minutes. The bath was cooled to 78°C and it was drained to obtain a treated material.
2. Polyester Dyeing: The bath was loaded with the treated material obtained in step (1) and 888 liters of water. The auxiliaries inclduing Dep.ACA B-Liq. (1 gm/liter), sodium acetate (0.5 gm/liter), Sunsoft LM7 (0.7 gm/lit), Levocol CWS (1.3 gm/liter) and acetic acid (1 gm/liter) were added to the bath. The bath was heated to 60°C. The bath pH was adjusted and maintained between 5 to 5.5. The disperse dyes namely Coralene Brilliant Red HP3BS (0.002%) and Coralene Black RLS (2.25%) were added to the bath over 20 minutes. The bath was heated to 90°C at the rate of 2.5°C/minute followed by heating the bath from 90°C to 130°C at the rate of 1.5°C/minute. The material was run in the bath at 130°C for 40 minutes of the residence time. The bath was cooled from 130°C to 90°C at the rate of 1.5°C/minute followed by cooling the bath from 90°C to 74°C at the rate of 2.5°C/minute. The carbonized cutting shade of material was matched with carbonized standard cutting shade. Upon matching of the shade, the bath was drained to obtain a dyed material.
3. Hot reduction clearing: The bath was loaded with the dyed material obtained in step (2) and 888 liters of water. The bath was heated to 60°C. 3 gm/liter of sodium dithionite and 3 gm /liter of caustic were added at 60°C. The bath was heated to 80°C. The material was run in the bath for 20 minutes. The bath was cooled to 74°C and the bath was drained after treatment to obtain a treated dyed material without excess disperse dyes and auxiliaries.
4. Hot reduction clearing: The treatment of hot reduction clearing was repeated as per step (3) and the bath was drained after the treatment to obtain a treated dyed material.
5. Hot wash: The bath was loaded with the treated dyed material obtained in step (4) and 888 liters of water. The bath was heated to 80°C. The material was run in the bath at 80°C for 10 minutes. The bath was drained after treatment to obtain a washed dyed material.
6. Neutralization: The bath was loaded with the washed dyed material obtained in step (5) and 888 liters of water. Acetic acid solution (33%) as neutralizaing agent was added to the bath to adjust the pH between 5 to 5.5. The material was run in the bath for 10 minutes while maintaining the pH between 5 to 5.5. The bath was drained after treatment to obtain a neutralized dyed material.
7. Cotton Dyeing: The bath was loaded with the neuttralized dyed material obtained in step (6) and 888 liters of water. The auxiliaries inclduing Dep. ACA B-Liq. (1 gm/liter), Albatex AB55 (0.5 gm/liter) and Orgakol TSP (0.5 gm/lit) were added to the bath. The bath was heated to 50°C. The disperse dyes namely Corafix yellow ECO+ (0.40%), Corafix red ECo+ (0.13 %) and Corafix Black GDE (7.83 %) were added to the bath over 20 minutes at 50°C. The material was run for 10 minutes. Glauber's salt (115.2 Kg) was added to the bath over 40 minutes. The material was run in the bath for 20 minutes. Sodium carbonate (6 gm/liter) was added to the bath over 20 minutes. The bath was run for 5 minutes. Sodium hydroxide (1.90 gm/liter) was added to the bath over 30 minutes. The bath was run for 5 minutes. The bath was heated to raise the temperature from 50°C to 60°C. The material was run in the bath at 60°C for 50 minutes. The shade cutting of the material was checked and compared with standard shade cutting. Upon depth match, the bath was drained to obtain a dyed material.
8. Wash with water: The bath was loaded with the dyed material obtained in step (7) and 888 liters of water. The material was run in the bath for 10 minutes at 25°C. The bath was drained after treatment to obtain a washed dyed material.
9. Wash with water: The treatment of wash with water was repeated as per step (8) and the bath was drained after the treatment to obtain a treated dyed material.
10. Neutralization: The bath was loaded with the treated dyed material obtained in step (9) and 888 liters of water. Acetic acid solution (33%) as neutralizaing agent was added to the bath to adjust bath pH between 5 to 5.5. The bath was run for 10 minutes while maintaining the pH between 5 to 5.5. The bath was drained after treatment to obtain a neutralized dyed material.
11. Treatment with wash off agent: The bath was loaded with the neuttralized dyed material obtained in step (10) and 888 liters of water. Diakol ECO (2 gm/liter) was added. The bath was heated to 85°C and the material was run in the bath for 20 minutes at maintained temperature. The bath was drained upon treatment to obtain a treated dyed material.
12. Hot wash: The bath was loaded with the treated dyed material obtained in step (11) and 888 liters of water. The bath was heated to 85°C. The material was run in the bath for 10 minutes. The bath was drained after treatment to obtain a washed dyed material.
13. Hot wash: The bath was loaded with the washed dyed material obtained in step (12) and 888 liters of water. The bath was heated to 85°C. The material was run in the bath for 10 minutes. The bath was drained after treatment to obtain a washed dyed material.
14. Wash with water: The bath was loaded with the washed dyed material obtained in step (13) and 888 liters of water. The material was run in the bath for 10 minutes at the temperature of 25°C. The bath was drained after treatment to obtain a washed dyed material.
15. Wash with water: The dyed material obtained in step (14) is once again subjected to wash with water according to step (14) and the bath is drained after wash to obtain a washed dyed material; and
16. Dye-fixing: The bath was loaded with the washed dyed material obtained in step (14) and 888 liters of water. Alwafix WFF (1.2 gm/liter) was added to the bath. The material was run in the bath for 10 minutes. The bath was drained after treatment to obtain a dyed material.

RESULTS:
• Number of steps: 16
• Time: approx.10 Hours 36 minutes,
• Water consumption:14760 Liters,
• Effluent drained: 14040 Liters,
• Glauber's Salt used: 115.2 Kg,
• Cost of the dyeing process: Rs. 36627/-,
• Depth of the black color: 100% with STD, and
• Surface smoothness of the dyed material was scrutinized manually and it was found to be satisfactorily fine with no mentionable changes.
• Color fastness properties
• The dyed polyester-cotton blend materials "A" prepared according to example 1 was tested for the color fastness properties i.e. color fastness to wash and color fastness to rubbing by ISO 105-C06: A2S and ISO 105-x12 respectively.
• The color fastness property to wash of dyed fabric sample A was tested and rating of color staining to Cotton/ Nylon/ Polyester/ Acrylic/ Wool for the dyed material A was being rated 4.
• The color fastness properties to both dry and wet rubbing of dyed fabric sample A was tested and color fastness to both dry and wet rubbing for the sample A was being rated 4 and 2 respectively.

Reference Example 2:
Conventional method of dyeing of polyester -cotton blend
The polyester-cotton blend (80:20) Knit PC Fleece construction having 270-280 gsm (SAMPLE "B") was used herein.
i. Hot Boiling: The material (240 Kg ) was loaded in the bath. The bath was filled up with 1440 liters of water and the auxiliaries including Exhosperse HC (0.7 gm/liter), Exowet ES (1 gm/liter) and Dep. ACA B-Liq. (0.5 gm/liter) were added in the bath. The temperature of the bath was raised to 90°C and the material was run in the bath for 10 minutes. The bath was cooled to 78°C and it was drained to obtain a treated material.
ii. Pre-treatment (scouring and cationization in a single bath): Machine bath was loaded with the treated material obtained in step (i) and 888 liters of water. To this, auxiliaries namely 0.70 gm/liter of Exhosperse HC, 1 gm/liter of Exowet ES, and 0.5 gm /liter of Dep. ACA B-Liq. were added. The bath was heated to raise the temperature to 60°C. The material was run in the bath for 10 minutes. To this bath, 9.75 Kg of caustic soda was added at 60°C to adjust the pH of the bath to 11 to 11.5 and the bath was run for 10 minutes. 39 Kg of cationizing agent, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (Rishlyte® 9098) was added to the bath at 60°C in 10 minutes and the bath was allowed to run for 3 minute. The temperature of the bath was increased to 85°C by 3°C/minute. Cationization was carried out at 85°C by running the material in the bath for 45 minutes. The bath was cooled to 78°C in 5 minutes. The bath was drained to obtain a cationized material.
iii. Hot wash: Machine bath was loaded with the cationized material obtained in step (ii) and 888 liters of water. The bath was heated to 80°C. The cationized material was run in the bath for 10 minutes. The bath was drained after treatment to obtain a washed cationized material.
iv. Neutralization: Machine bath was loaded with the washed cationized material obtained in step (iii) and 888 liters of water. Acetic acid solution (33%) as neutralizaing agent was added to the bath to adjust the bath pH between 5 to 5.5. 0.5 gm /liter of Invatex AC was added to the bath. The cationized materal was run in the bath for 10 minutes while maintaining the pH between 5 to 5.5. The bath was drained after treatment to obtain a neutralized cationized material.
v. Polyester Dyeing: Machine bath was loaded with the neutralized material obtained in step (iv) and 888 liters of water. The auxiliaries inclduing ACA B-Liq. (2 gm/liter), sodium acetate (0.5 gm/liter), Sunsoft LM7 (0.7 gm/liter), Levocol CWS (1.3 gm/liter) and acetic acid (1 gm / liter) were added to the bath. The bath was heated to 60°C. The pH of the bath was adjusted and maintained between 5 to 5.5. The disperse dyes namely Coralene Brilliant Red HP3BS (0.002%) and Coralene Black RLS (2.25%) were added to the bath over 20 minutes. The bath was heated to 90°C at the rate of 3°C/minute followed by heating the bath from 90°C to 110°C at the rate of 2.5°C/minute further heating the bath from 110°C to 130°C at the rate of 1.5°C/minute. The material was run in the bath at 130°C for 40 minutes. The bath was cooled from 130°C to 110°C at the rate of 1.5°C/minute followed by cooling the bath from 110°C to 90°C at the rate of 2.5°C/minute further the bath was cooled from 90°C to 74°C at the rate of 3°C/minute. The carbonized cutting shade of material was matched with carbonized standard cutting shade. Upon matching of the shade, the bath was drained to obtain a cationized dyed material.
vi. Hot reduction clearing: Machine bath was loaded with the cationized dyed material obtained in step (v) and 888 liters of water. Sodium dithionite (4 gm/liter) and sodium hydroxide (4 gm /liter) were added over 8 minutes. The bath was heated to 80°C over 6 minutes. The cationized dyed material was run in the bath for 10 minutes. The bath was drained after treatment to obtain a washed cationized dyed material.
vii. Hot wash: Machine bath was loaded with the washed cationized dyed material obtained in step (vi) and 888 liters of water. The bath was heated to 80°C. The cationized dyed material was run in the bath for 10 minutes. The bath was drained thereafter to obtain a washed cationized dyed material.
viii. Neutralization: Machine bath was loaded with the washed cationized dyed material obtained in step (vii) and 888 liters of water. Acetic acid solution (33%) was added to the bath to adjust the bath pH between 5 to 5.5. 0.5 gm /liter of Invatex AC was added to the bath. The cationized dyed materal was run in the bath for 10 minutes while maintaining the pH between 5 to 5.5. The bath was drained after treatment to obtain a neutralized cationized dyed material.
ix. Wash with water: Machine bath was loaded with the neutralized cationized dyed material obtained in step (viii) and 888 liters of water. The cationized dyed material was run in the bath for 10 minutes at 25°C. The bath was drained after treatment to obtain a washed cationized dyed material.
x. Cotton dyeing: Machine bath was loaded with the washed cationized dyed material obtained in step (ix) and 888 liters of water. The auxiliaries inclduing Dep. ACA B-Liq. (1 gm/liter), Albatex AB55 (0.5 gm/liter) and Orgakol TSP (0.5 gm/liter) were added to the bath. The bath was heated to 50°C. The disperse dyes namely Corafix yellow ECO+ (0.40%), Corafix red ECo+ (0.13 %) and Corafix Black GDE (7.83 %) were added to the bath over 20 minutes at 50°C. The bath was run for 20 minutes. The first alkali of sodium bicarbonate (5 gm/liter) was added in the bath over 20 minutes followed by addition of second alkali of sodium hydroxide (1.5 gm/liter) over 30 minutes to adjust the pH of the bath between 11 to 11.5. The bath was run for 5 minutes and further it was heated to raise the temperature of the bath from 50°C to 60°C at the rate of 1.5°C/minute. The material was run in the bath for 40 minutes of the residence time to dye cotton fiber component of the material. A depth of the shade of the dyed material was checked by taking small window cutting. The bath was drained after dyeing to obtain a dyed material.
xi. Wash with water: Machine bath was loaded with the dyed material obtained in step (x) and 888 liters of water. The dyed material was run in the bath for 10 minutes at 25°C. The bath was drained after treatment to obtain a washed dyed material.
xii. Neutralization: Machine bath was loaded with the washed dyed material obtained in step (xi) and 888 liters of water. Acetic acid solution (33%) was added to the bath to adjust the bath pH between 5 to 5.5. 0.5 gm /liter of Invatex AC was added to the bath. The dyed material was run in the bath for 10 minutes while maintaining pH between 5 to 5.5. The bath was drained after treatment to obtain a neutralized dyed material.
xiii. Treatment with wash off agent: Machine bath was loaded with the neutralized dyed material obtained in step (xi) and 888 liters of water. Diakol ECO (2 gm/liter) was added. The bath was heated to 85°C and the material was run in the bath for 20 minutes at maintained temperature. The bath was drained upon the completion of the treatment to obtain a treated dyed material.
xiv. Hot wash: Machine bath was loaded with the treated dyed material obtained in step (xiii) and 888 liters of water. The bath was heated to 80°C. The dyed material was run in the bath for 10 minutes. The bath was drained thereafter to obtain a washed dyed material.
xv. Wash with water: Machine bath was loaded with the washed dyed material obtained in step (xiv) and 888 liters of water.The dyed material was run in the bath for 10 minutes of residence time at 25°C. The bath was drained thereafter to obtain the dyed material.

RESULTS:
• the number of steps: 15;
• the cost of the dyeing is around Rs. 38768/-;
• the total water consumption is around 13872 Liters;
• the total time consumption is around 10 Hour 42 minutes;
• the effluent generated is around 13150 Liters; and
• Depth of the black color: 100% with STD;
• Surface smoothness of the dyed material was scrutinized manually and it was found to be satisfactorily fine with no mentionable changes;
• Color fastness properties
The dyed polyester-cotton blend materials "B" prepared according to the example 2 was tested for the color fastness properties i.e. color fastness to wash and color fastness to rubbing by ISO 105-C06: A2S and ISO 105-x12 respectively.
• The color fastness property to wash of dyed fabric sample B was tested and rating of color staining to Cotton/ Nylon/ Polyester/ Acrylic/ Wool for the dyed material B was being rated 4.
• The color fastness properties to both dry and wet rubbing of dyed fabric sample B was tested and color fastness to both dry and wet rubbing for the sample B was being rated 4 and 2 respectively.

Example 3:
A method of dyeing of polyester-cotton blend according to the invention
The polyester-cotton blend (80:20) Knit PC Fleece construction having 270-280 gsm (SAMPLE "C") was used herein.
a) Hot Boiling: A machine bath was loaded with 240 Kg of the polyester-cotton blend material (Sample C) and 1440 liters of water. The auxiliaries consisting of 1 gm/liter of Exo Wet ES, 0.5 gm/liter of Dep. ACA B-Liq. and 0.7 gm/liter of Exsosperse HC were added to the bath over 20 minutes. The bath was heated to 90°C and the material was run in the bath for 10 minutes. The bath was cooled to 78°C. The bath was drained after the treatment to obtain a treated material.
b) Polyester Dyeing: The machine bath was loaded with the treated material obtained in step (a) and 888 liters of water. The auxiliaries inclduing Dep. ACA B-Liq. (1 gm/liter), sodium acetate (0.5 gm/liter), Sunsoft LM7 (0.7 gm/liter), Levocol CWS (1.3 gm/liter) and acetic acid (1 gm/liter) were added to the bath. The bath pH is checked and it is maintained in the range of 5 to 5.5. The bath was heated to 60°C. The disperse dyes namely Coralene brilliant red HP3BS (0.002%) and Coralene black RLS (2.25%) were added to the bath over 20 minutes. The bath was heated to 90°C at the rate of 3°C/minute followed by heating the bath from 90°C to 110°C at the rate of 2.5°C/minute further heating the bath from 110°C to 130°C at the rate of 1.5°C/minute. The material was run in the bath at 130°C for 40 minutes of the residence time. The bath was cooled from 130°C to 110°C at the rate of 1.5°C/minute followed by cooling the bath from 110°C to 90°C at the rate of 2.5°C/minute, further the bath was cooled from 90°C to 74°C at the rate of 3°C/minute. The carbonized cutting shade of material was matched with carbonized standard cutting shade. Upon matching of the shade, a dyed material was obtained after draining of the bath.
c) Pre-treatment consisting of scouring and cationization with simultaneous reduction clearing in a single bath: The machine bath was loaded with the dyed material obtained in step (b) and 888 liters of water. 0.5 gm/liter of Dep. ACA B-Liq. and 0.7 gm/liter of Exsosperse HC were added in the bath. The bath was heated to raise the temperature to 60°C. 7.50 gm/liter of sodium hydroxide was added to the bath to adjust the pH between 11 to 11.5. The material was run in the bath for 10 minutes of residence time. 30 gm/liter of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (RL 9098) was added to the bath at 60°C followed by running the dyed material in the bath for 10 minutes of residence time. The bath was heated to raise the temperature to 85°C at the rate of 3°C/minute followed by running the material in bath for 45 minutes of the residence time. The bath was cooled to 74°C. 3 gm/liter of sodium dithionite was added to bath followed by heating the bath to raise the temperature to 80°C. The material was run in the bath for 20 minutes of the residence time. The bath was cooled to 74°C. The bath was subsequently drained to obtain a cationized dyed material.
d) Hot wash: The machine bath was loaded with the cationized dyed material obtained in step (c) and 888 liters of water. The bath was heated to 80°C. The cationized dyed material was run in the bath for 10 minutes. The bath was drained thereafter to obtain a cationized dyed material.
e) Neutralization: The machine bath was loaded with the cationized dyed material obtained in step (d) and 888 liters of water. Acetic acid solution (33%) was added to the bath to adjust the pH between 5 to 5.5. The cationized dyed material was run in the bath for 10 minutes while maintaining the pH between 5 to 5.5. The bath was drained after treatment to obtain a neutralized cationized dyed material.
f) Cotton dyeing: The machine bath was loaded with the neutralized cationized dyed material obtained in step (e) and 888 liters of water. 1 gm/liter of Dep. ACA B-Liq., 0.5 gm/liter of Albatex AB55, and 0.5 gm/liter of Orgakol TSP were added to the bath. The bath was heated to raise the temperature of the bath to 50° C. 0.40 % of Corafix Yellow ECO+, 0.13 % of Corafix Red ECO+ and 7.83 % of Corafix Black GDE were added to the bath over 20 minutes at 50°C. The bath was run for 20 minutes. The first alkali of sodium bicarbonate (6 gm/liter) was added in the bath over 20 minutes followed by addition of second alkali of sodium hydroxide (1.9 gm/liter) over 30 minutes to adjust the pH of the bath between 11 to 11.5. The bath was run for 5 minutes. Further, the bath was heated to raise the temperature of the bath from 50°C to 60°C at the rate of 1.5°C /minute. The material was run in the bath for 50 minutes of the residence time to dye cotton fiber component of the material. A depth of the shade of the dyed material was checked by taking small window cutting. The bath was drained after dyeing to obtain a dyed material.
g) Wash with water: The machine bath was loaded with the dyed material obtained in step (f) and 888 liters of water. The dyed material obtained in step (e) was run in the bath for 10 minutes of the residence time at 25°C. The bath was drained to obtain a dyed material.
h) Neutralization: The machine bath was loaded with the dyed material obtained in step (g) and 888 liters of water. Acetic acid solution (33%) was added to the bath to adjust the bath pH between 5 to 5.5. The dyed material was run in the bath for 10 minutes while maintaining pH between 5 to 5.5. The bath was drained after treatment to obtain a neutralized dyed material.
i) Treatment with wash off agent: The machine bath was loaded with the neutralized dyed material obtained in step (h) and 888 liters of water. 2 gm/liter of Diakol ECO was added to the bath. The bath was heated to 95°C. The dyed material was run in the bath for 15 minutes at maintained temperature. The bath was cooled to 80°C. The bath was drained upon treatment to obtain a treated dyed material.
j) Hot wash: The machine bath was loaded with the treated dyed material obtained in step (i) and 888 liters of water. The bath was heated to 85°C. The dyed material obtained in step (i) was run in the bath for 10 minutes. The bath was drained thereafter to obtain a washed dyed material.
k) Wash with water: The machine bath was loaded with the washed dyed material obtained in step (j) and 888 liters of water. The dyed material was run in the bath for 10 minutes at 25°C. The bath was drained thereafter to obtain a dyed material.

RESULTS:
• the number of steps: 11;
• the cost of the dyeing is around Rs. 33076;
• the total water consumption is around 10320 Liters;
• the total time consumption is around more than 9 Hours 30 minutes;
• the effluent generated is around 9600 Liters; and
• eliminates the use of chemicals like dye-fixer and glauber's salt.
• Depth of the black color: 100% with STD;
• Surface smoothness of the dyed material was scrutinized manually and it was found to be satisfactorily fine with no mentionable changes;
• Color fastness properties
• The dyed polyester-cotton blend materials "C" prepared according to the example 3 was tested for the color fastness properties i.e. color fastness to wash and color fastness to rubbing by ISO 105-C06: A2S and ISO 105-x12 respectively.
• The color fastness property to wash of dyed fabric sample C was tested and rating of color staining to Cotton/ Acrylic/ Wool for the dyed material C was being rated 5 and for Nylon/ Polyester was being rated 4 to 5.
• The color fastness properties to both dry and wet rubbing of dyed fabric sample C was tested and color fastness to both dry and wet rubbing for the sample C was being rated 5 and 3 respectively.

According to the above-mentioned results of examples 1 to 3, it is evident that the current invention reduces number of steps to 11, 24 to 32 % of fresh water consumption, 25 to 32 % of effluent generated and drained, 8 to 14% of time consumed in the dyeing and 7 to 18 % of cost of dyeing. At the same time it eliminates the use of dye-fixing agent as well as use of glauber's salt. It also enhances the colour fastness to wash as well as to rubbing properties with satisfying strength or depth of colour of the dyed material. Thus, the process of dyeing of polyester-cotton blends material of the invention comprising polyester dyeing followed by pre-treatment consisting of scouring and cationization with simultaneous alkaline reduction clearing in the single bath and finally cotton dyeing along with other steps is cost-effective and eco-friendly.