DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)

&

THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10, Rule 13]

A PROCESS AND SYSTEM FOR COLORATION OF YARN/FABRIC AND GARMENT THEREFROM;

ARVIND LIMITED, A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS NARODA ROAD, AHMEDABAD- 380025, GUJARAT, INDIA

THE FOLLOWING SPECIFICATION PRTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

TECHNICAL FIELD OF INVENTION
The present invention relates to a process of coloration of yarn or fabric and/or more particularly, to a spray coloration process and unit for yarn and/or fabric.

BACKGROUND OF THE INVENTION
Different types of yarn coloration methods are available in denim industry. The coloration of yarn is performed in various forms including sheet form, rope form, beam form and the like. In current state of art, sheet form and rope form are commonly used. However, these technologies consume large amount of water and chemicals. Further, the discharged water after coloration process needs to be treated in effluent treatment plant before discharging into the eco-system which increases the cost of coloration.

To overcome this challenge, a spray form technique and a foam form coloration technique are introduced in which dye is applied directly to the yarn without any dyebath. In foam coloration process, the dye is applied in the foam form. In the spray coloration process, the mist of dye coming from rotor unit is used to dye the yarn. However, it is observed that the fabric obtained from said dyed yarn with spray coloration process has challenges of shade variation across the width, poor ozone fastness property, poor rubbing fastness property, dull in appearance and constrain of increasing dye concentration. Also, the machine needs to be cleaned once machine is stopped or else it causes chocking of spray nozzles.
Accordingly, there is a need of a process and system to facilitate uniform dyeing of yarn and fabric by solving at least one of the aforementioned challenges.

SUMMARY OF THE INVENTION
In one aspect, the present invention provides a system for coloration of yarns or fabric. The system includes a spray unit having a plurality of spray rotor and a dye supply pipe positioned in a closed chamber. A fixation zone is connected to the spray unit. A washing unit is connected to the fixation zone. A drying unit is connected to the washing unit. The fixation zone and the spray unit include a steamer connected therebetween in case of coloration with reactive dye, sulphur dye. The closed chamber has an inert gas or non-reactive gas or non-oxidize gas that includes nitrogen or helium. The rotor rotates at speed of about 250 – 3500 rpm. The dyes are selected from the group of indigo, sulphur, vat, reactive, and oxidative colours.

In another aspect, the present invention provides a process for coloration of dye or fabric. In the first step, a dye is sprayed on a yarn or a fabric in a spray unit in a non-reactive atmosphere in a closed chamber. The dye molecules are sprayed on the surface of the yarn or the fabric and let penetrate gradually into the yarn or the fabric till the dye gets oxidized. In the next step, the dyed yarn or fabric is passed through a fixation zone. In the next step, the dyed yarn or fabric is washed in a washing unit. In the last step, the washed yarn or fabric is dried in a drying unit.
The dyed yarn or fabric taken out from the spray unit is passed through a steamer. The closed chamber has an inert gas or non-reactive gas or non-oxidize gas that includes nitrogen or helium for keeping indigo dye in leuco form or in reduced form thereby increasing effective contact time of dye with yarn. The contact time ranges from about 30 sec to about 40 sec. A garment may be manufactured by the fabric coloured by the process.

BRIEF DESCRIPTION OF DRAWING
Fig: 1 shows a flow chart of a process of coloration of yarn or fabric using spray unit.

DETAILED DESCRIPTION OF INVENTION
Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to particular structure of the invention selected for illustration in the drawings and are not intended to define or limit the scope of the invention.

In one aspect, the present invention provides a process of coloration of a yarn or fabric. The process includes the steps of colouring of yarn or fabric under neutral environment, fixing, drying and sizing. In another aspect, the present invention provides a system of coloration of yarn. The system includes a closed spray unit providing neutral environment connected with a fixation zone. The fixation zone and the spray unit include a steamer connected there between in case of coloration process with reactive dye, sulphur dye and the like. The fixation zone is connected with a washing unit. The washing unit is connected with a drying unit.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures.

Referring to the FIG. 1, a process for coloration of a yarn or fabric using a spray unit is shown. In an embodiment, the coloration process comprises steps of preparing a sheet of yarns (102), pre-treatment (104) and washing (106). After washing, the sheet of yarns is further processed into at least one spray unit (108). The washed yarn sheet undergoes coloration process in the spay unit (108). The colours/ dyes are dyes selected from the group of indigo, sulphur, vat, reactive, and oxidative colours.

A system (100) for coloration of a yarn or fabric includes a spray unit (108) connected with a fixation zone (112). The fixation zone (112) and the spray unit (108) include a steamer (110) connected there between in case of coloration process with reactive dye, sulphur dye and the like. The fixation zone (112) is connected with a washing unit (114) wherein the dyed yarn or fabric is subjected to open atmosphere for a predetermined time for oxidation of the dye. The washing unit (114) is connected with a drying unit (116).

In accordance with an embodiment, in first step, a yarn sheet is sprayed with a dye at least by one spray in a non-reactive atmosphere. In a next step, the dyed yarn is kept in the non-reactive medium for a predetermined time in the fixation zone. In the next step, the dyed yarn is subjected to open atmosphere for oxidation of dyes and then washed in a washing unit. In the next, the washed yarn is dried in the drying unit followed by sizing process, drying and winding if required.

In accordance with an embodiment of the present invention, at least one spray unit (108) comprises a plurality of spray rotor (Not Shown), a closed chamber (Not shown) and a plurality of dye supply pipe (Not shown). The closed chamber includes the rotor placed at predefined position therein and dye supply pipe. It is understood here that a steamer (110) can be used optionally. During coloration process, the rotors rotate at speed of about 250 – 3500 rpm. The coloration process is performed by pulverization of dye and chemicals.

In accordance with the present invention, the arrangement is kept in a closed chamber. The dye is supplied on the rotors by the supply pipe in perpendicular direction. In an embodiment, the plurality of rotor is placed in series in the spray unit (108) having the supply pipes to supply the dye continuously. The dye is sprayed on the yarn or a fabric by rotation of the rotors. The dye molecules are sprayed on the surface of the yarn and penetrates gradually into the yarn till the dye gets oxidized. Different chemicals are used to keep dye molecules in reduced form. Dyeing composition includes Anti-foaming agent, sequestering agent, wetting agent, dispersing agent, anti-migrating agent, caustic, and Reducing agent. Hydro is used to kept dye molecules in reduce form.

In accordance with the present invention, the closed chamber has an inert gas or non-reactive gas or non-oxidized gas that includes nitrogen or helium. The pressure of the inert gases ranges between 150 – 200 Bar. In an exemplary of present invention, the pressure of the inert gases is 180 Bar. It keeps indigo dye in leuco form or in reduced form which increases effective contact time of dye with yarn and results into uniform penetration of dye molecule in yarn. In accordance with an embodiment, the contact time ranges from about 30 sec to about 40 sec.

In next step, the dyed yarn is passed into a fixation zone (112). The fixation zone (112) has similar environment as that of the spray unit (108). The use of a steamer (110) depends on type of colour which can be used during coloration process. In the next step, the coloured yarn undergoes washing (114) and drying (116) process. In the next step, the coloured yarn undergoes continuous sizing (118) and drying (120) process. In next step, the dried yarn undergoes winding (122) process. Thereafter, the coloured yarn undergoes fabric making process that includes weaving or knitting and the dyed fabric undergoes garment making process.

In spraying process conducted in the spray unit of the present invention, the colour gets more time to penetrate inside the yarn that helps to solve problem of shade variation as well as improve the ozone fastness property, rubbing fastness property, and enhances brightness of the fabric. The spraying process of the present invention solves the problem of nozzle chocking by using inert and non-reactive gas i.e. nitrogen. It helps to keep dye in the reduced form, so, the use of higher concentration of dye is possible. In this process, the colour/ dye is uniformly distributed on the yarn.
Example:
The table shows the dye composition for dying the yarn or the fabric. The rotors rotate at 2000 rpm.
Ingredient Amount (GPL)
Anti-foaming agent 5
Sequestering agent 1
Wetting agent 8
Dispersing agent 5
Anti-migrating agent 2
Caustic 20
Indigo dye 180
Reducing agent 50

The embodiments of the invention shown and discussed herein are merely illustrative of modes of application of the present invention. Reference to details in this discussion is not intended to limit the scope of the claims to these details, or to the figures used to illustrate the invention.
It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.

,CLAIMS:WE CLAIM:
1. A system for coloration of yarns or fabric, the system comprising:
a spray unit (108) having a plurality of spray rotor and a plurality of dye supply pipe positioned in a closed chamber; a fixation zone (112) connected to the spray unit (108);
a washing unit (114) connected to the fixation zone (112); and
a drying unit (116) connected to the washing unit (114).

2. The system as claimed in claim 1, wherein the fixation zone (112) and the spray unit (108) include a steamer (110) connected there between for coloration with reactive dye, sulphur dye.

3. The system as claimed in claim 1 or 2, wherein the closed chamber and has an inert gas or non-reactive gas or non-oxidize gas that includes nitrogen or helium at a pressure that ranges between 150 – 200 bar.

4. The system as claimed in claims 1-3, wherein the rotor rotates at speed of about 250 – 3500 rpm.

5. The system as claimed in claims 1-4, wherein the dyes selected from the group of indigo, sulphur, vat, reactive, and oxidative colours.

6. A process for coloration of dye or fabric, the process comprises the steps of:
spraying a dye on a yarn or a fabric in a spray unit (108) in a non-reactive atmosphere in a closed chamber, the dye molecules are sprayed on the surface of the yarn and let penetrate gradually into the yarn till the dye gets oxidized;
passing the dyed yarn or fabric through a fixation zone (112);
washing the dyed yarn or fabric in a washing unit (114); and
drying the washed yarn or fabric in a drying unit (116).

7. The process as claimed in claim 6, wherein the dyed yarn or fabric taken out from the spray unit is passed through a steamer (110) in case of reactive and sulphur dye.

8. The process as claimed in claim 6, wherein the closed chamber has an inert gas or non-reactive gas or non-oxidize gas that includes nitrogen or helium for keeping indigo dye in leuco form or in reduced form thereby increasing effective contact time of dye with yarn.

9. The process as claimed in claim 8, wherein the contact time ranges from about 30 sec to about 40 sec.

10. A garment manufactured by the fabric colored by the process as claimed in claims 6-9.

Dated this 24th day of January, 2020
For Arvind Limited
By their Agent

(GIRISH VIJAYANAND SHETH) (IN/PA 1022)
KRISHNA & SAURASTRI ASSOCIATES LLP