The present invention relates generally to the field
5 of textile dyeing and more particularly, the present
invention relates to a process for optimized dyeing of
textiles using natural dyes based on a continuous dyeing
mechanism.
Background of the invention
10 [0002] Textile materials are usually dyed by transferring
and diffusing one or more types of desirable dyes to the
textile for producing a wide range of shades. Typically,
reactive dyes are used for dyeing textiles. However, the
reactive dyes may be of a synthetic origin and comprise
15 complex aromatic structure, which mitigates their
biodegradation process. Further, it has been observed that
existing dyeing processes for dyeing textiles with natural
dyes are associated with one or more issues, which may
include, but are not limited to, inadequate reproducibility
20 of shades, non-uniformity of dyeing, low color fastness with
respect to multiple washes and inadequate lightfastness of
the dyed colors. Further, the implementation of natural dye
application at industrial scale is still unsuccessful.
[0003] Furthermore, existing processes for dyeing textiles
25 with natural dyes are not able to determine and achieve
desired dyeing conditions (e.g. fabric process flow, etc.)
for adequate dyeing. Further, it has been observed that the
existing dyeing processes using natural dyes are not able to
provide adequate dyeing results during bulk dyeing of
30 textiles. The existing processes are not able to define one
or more dyeing parameters, e.g. temperature, dye
concentration percentage, moister, pH, time of contact of
3
dyes, dye fixing condition, temperature of fixation, washing
method, etc. effectively. Further, dyeing of textiles using
natural dyes requires optimization of the dyeing parameters,
which the existing processes are not able to optimize
5 effectively, therefore leading to loss of color of natural
dyed textile with subsequent washing and further degradation
of the quality of dyed textiles. Furthermore, the existing
dyeing processes are not able to provide for achieving
desired wet fastness properties and produces textiles with
10 shade variations and unevenness. Yet further, the existing
dyeing processes do not provide appropriate mordanting during
dyeing and are not sustainable, environment friendly and cost
effective.
[0004] In light of the aforementioned drawbacks, there is a
15 need for a dyeing process which provides for optimizing
dyeing of textiles using natural dyes. There is a need for a
dyeing process which provides for adequate color
reproducibility, moderate level of wet fastness properties
and uniform dyeing. Further, there is a need for a dyeing
20 process which provides for accurate dyeing results during
bulk dyeing of textiles and provides for adequate maintenance
of wet fastness properties. Furthermore, there is a need for
a dyeing process which provides for producing textiles
without shade variations and unevenness and appropriate
25 mordanting during dyeing. Yet further, there is a need for a
dyeing process which is sustainable, environment friendly and
cost effective.
Summary of the invention
[0005] In various embodiments of the present invention, a
30 process for optimized dyeing of textiles based on a
continuous dyeing mechanism is provided. The process
comprises padding a Ready for Dye (RFD) textile in a dye
liquor. The dyeing liquor is prepared from one or more natural
dye pastes. Further, the process comprises squeezing the dyed
4
textile for removing excess dye liquor from the dyed textile.
Furthermore, the process comprises wetting the squeezed dyed
textile for uniform dyeing. Lastly, the process comprises
steaming the wet dyed textile for fixation of dye on the dyed
5 textile.
Brief description of the accompanying drawings
[0006] The present invention is described by way of
embodiments illustrated in the accompanying drawings wherein:
10 [0007] FIG. 1 illustrates a continuous dyeing range (CDR)
machine for dyeing textiles with natural dyes, in accordance
with an embodiment of the present invention; and
[0008] FIG. 2 illustrates a wash-off range unit for washing
the dyed textiles, in accordance with an embodiment of the
15 present invention.
Detailed description of the invention
[0009] The present invention discloses a process for
optimized dyeing of textile using natural dyes based on a
20 continuous dyeing mechanism. The present invention provides
for a dyeing process that provides adequate color
reproducibility, moderate level of wet fastness properties
and uniform dyeing. The present invention further provides
for determining and achieving precise dyeing conditions for
25 adequate dyeing. Further, the present invention provides for
adequate dyeing results during bulk dyeing of textiles and
optimized dyeing parameters such as temperature sensitivity,
moister, pH, time of contact of dyes with fixing condition
of temperature, washing method, etc. for improving color and
30 quality of the textile dyed with the natural dyes in a
continuous dyeing mechanism. Furthermore, the present
invention provides for a dyeing process providing adequate
5
maintenance of wet fastness properties without shade
variations and with evenness during dyeing.
[0010] The disclosure is provided in order to enable a person
having ordinary skill in the art to practice the invention.
5 Exemplary embodiments herein are provided only for
illustrative purposes and various modifications will be
readily apparent to persons skilled in the art. The general
principles defined herein may be applied to other embodiments
and applications without departing from the scope of the
10 invention. The terminology and phraseology used herein is for
the purpose of describing exemplary embodiments and should
not be considered limiting. Thus, the present invention is
to be accorded the widest scope encompassing numerous
alternatives, modifications and equivalents consistent with
15 the principles and features disclosed herein. For purposes
of clarity, details relating to technical material that is
known in the technical fields related to the invention have
been briefly described or omitted so as not to unnecessarily
obscure the present invention.
20
[0011] In an embodiment of the present invention, textile
materials are dyed based on a continuous dyeing mechanism
with natural dyes. The continuous dyeing mechanism is carried
out using a continuous dyeing range which provides for
25 uninterrupted dyeing until the whole length of the textile
is dyed. In an exemplary embodiment of the present invention,
the textiles that are dyed with natural dyes in accordance
with the present invention may include, woven fabrics, terry
towels, sheeting fabrics and other textile materials.
30 Examples of terry towels may include terry towels made of
natural fiber (e.g. cotton) and other derivatives which may
include, but is not limited to, viscose, modal, tencel,
lyocell, wool, silk, etc., which may be in a pure form or in
a blended form with each other or existing synthetic fibers.
35 In an exemplary embodiment of the present invention, the
6
natural dyes may include, but are not limited to, natural
ayurvedic dyes, which may be derived from various plant herbs
having medicinal properties. The plant herbs may include, but
are not limited to, t.Chebula (haritaki), curcuma longa
5 (turmeric), rubia cordifolia (madder), butea monosperma
(flame of forest), indigofera tinctoria (indigo), iron vat,
paunica granatum (pomegranate), sea salt, areca nut,
myrobalan seeds, sappanwood, lac dye, saw palmetto, bitter
orange, rose mary, walnut, henna leaves, aloe vera, champa
10 flower, neem, cutch, catechu, onion, sandle wood, acacia
catechu, kerria lacca, mulberry tree, tegetas erecta, butea
monosperma, quercus infectoria, rubia cordifolia, plant
punica granatum and a combination thereof.
15 [0012] In an embodiment of the present invention, the
continuous dyeing mechanism for dyeing the textiles with the
natural dyes is carried out based on a continuous dyeing
range (CDR) operation. Further, the CDR operation is carried
out by optimizing one or more parameters associated with the
20 CDR operation. The one or more optimized parameters may
include, but are not limited to, temperature, moister, pH,
time of contact of dyes with fixing condition of temperature
and washing method. The optimization of parameters aids in
better fixation of dyes and achieving superior quality dyed
25 textiles.
[0013] The present invention would now be discussed in
context of embodiments as illustrated in the accompanying
drawings.
[0014] FIG. 1 illustrates a continuous dyeing range (CDR)
30 machine 100 for dyeing textiles with natural dyes, in
accordance with an embodiment of the present invention.
[0015] In an embodiment of the present invention, the CDR
machine 100 comprises a first feeding unit 102, a pad mangle
unit 104, an aeration unit 106, a thermax unit 108, a control
7
unit 110, a steam injection unit 112 and a wash-off range
unit 114. The CDR machine 100 is based on an E-control®
moister fix machine operation for providing easy and rapid
continuous dyeing of textiles. In an embodiment of the
5 present invention, the speed of the CDR machine 100 is
maintained in a range of between 10 meters and 60 meters per
minute, which provides an optimized speed of dyeing of the
textiles for efficient and effective dyeing.
10 [0016] In an embodiment of the present invention, a Ready
for Dyeing (RFD) textile is passed through the first feeding
unit 102 of the CDR machine 100. In an exemplary embodiment
of the present invention, the RFD is a pure cotton textile,
which is pre-treated prior to dyeing. In an exemplary
15 embodiment of the present invention, the pre-treatment
process of the RFD textile comprises singeing, enzymatic
desizing, scouring cum bleaching carried out using Benninger
continuous bleaching range, mercerization using Benninger
chain mercerization, bio scouring process or non-chlorine
20 based hydrogen peroxide scouring, neutralization and drying.
Further, the RFD textile has Tegwa of 8+ and instant
absorbency property. In an embodiment of the present
invention, the pad mangle unit 104 comprises a trough with a
dye liquor, which is used for dyeing the RFD textile.
25 [0017] In an embodiment of the present invention, the dye
liquor is prepared from the natural dyes for dyeing of the
RFD textile. In an exemplary embodiment of the present
invention, the dye liquor is prepared from a natural dye
paste and may be of any desirable color. The natural dye
30 pastes are prepared from one or more types of dye powder,
which is converted to a paste form by mixing with a plant
originated natural binder, water and a natural sea salt.
Further, a mordanting agent (i.e. a mordant) is added to the
dye paste based on at least a pre-mordanting process, a
35 simultaneous (meta) mordanting process, a post-mordanting
8
process, and preferably a simultaneous (meta) mordanting
process, for providing adequate binding property to dyes
during the RFD textile dyeing process. In an exemplary
embodiment of the present invention, the mordant used may
5 include, but is not limited to, iron salt based mordant,
aluminium salt based mordant, sea salt based mordant, or a
combination thereof. Advantageously, the natural dyes in
paste form are stable dyes and aids in overcoming settling
characteristics of natural dyes, which may be caused due to
10 bigger molecular size during dyeing in trough and further
aids to make the natural dyes suitable for padding
application. The natural dye paste is diluted by mixing the
dye paste with pH controlled water to form a dye liquor.
Further, pH of the water is maintained in the range of between
15 neutral to slightly acidic. In an exemplary embodiment of the
present invention, pH of the water is in a range of between
5 and 7. Further, in an embodiment of the present invention,
the pH of the dye liquor is maintained in the acidic range
of between 3.5 to 4.5, which aids in maintaining dye color
20 strength value and apparent color of dye during the dyeing
process.
[0018] In an embodiment of the present invention, the trough
is placed below the pad mangle unit 104. The RFD textile is
padded in the dye liquor present in the trough for dyeing
25 with the desired dye color using a kuster dyeing padding. The
dwell time for padding is in the range of between 3 to 4
minutes, which provides effective dyeing of the RFD textile.
[0019] In an exemplary embodiment of the present invention,
the desired dye colors associated with the natural dyes may
30 include one or more number of natural extracts from plant
herbs to achieve a desired color or shade. Examples of the
desired dye colors include, but are not limited to, yellow,
madder red, chebula black, brazil brown, cherry pink, bettle
pink, light pink, dark pink, pomo orange, oak brown, woad
35 blue, kassam olive and a combination thereof. The natural
9
dyes are used in one or more desired dosages for achieving
the desired dye color, which aids in providing appropriate
color fixation subsequent to washing.
5 [0020] In an embodiment of the present invention, subsequent
to dyeing of the RFD textile, the dyed textile is passed
through the pad mangle unit 104 for squeezing of the dyed
textile and removing excess dye liquor from the dyed textile.
In an exemplary embodiment of the present invention, pressure
10 in left, middle and right of the pad mangle unit 104 is
maintained at a specific pressure based upon the dye liquor
picked up by the dyed textile. In an embodiment of the present
invention, the pressure in the pad mangle unit 104 is
maintained at an optimum level to obtain the desired dye pick
15 up value. In an exemplary embodiment of the present
invention, the pressure in left, middle and right of the pad
mangle unit 104 is maintained in a range of between 15N to
40N. The pressure in the pad mangle unit 104 is maintained
based on the fabric quality and the dye liquor picked up by
20 the dyed textile. The said pressure range aids in preventing
center of selvedge color variation.
[0021] In an embodiment of the present invention, the
squeezed dyed textile is subsequently passed through the
aeration unit 106 for wetting the squeezed dyed textile and
25 obtaining an even dye result and even absorbency in the
textile material. Further, the aeration unit 106 removes air
bubbles from textile surface for uniform dyeing appearance
by bringing water and air in close contact. In an embodiment
of the present invention, the wet dyed textile from the
30 aeration unit 106 is passed through the thermax unit 108 and
steam injection unit 112 for steaming. The thermax unit 108
and the steam injection unit 112 comprises a steaming
chamber. In an exemplary embodiment of the present invention,
the steaming chamber of the thermax unit 108 and the steam
35 injection unit 112 further comprises five chambers for drying
10
and steaming the dyed textile. In an embodiment of the present
invention, the steaming aids in fixation of dyes on the dyed
textile. In an exemplary embodiment of the present invention,
the steaming of the dyed textile is carried out for a time
5 period in a range of between 2 minutes to 4 minutes depending
upon the color of the dyed textile. Advantageously, the said
time period range provides seamless dyeing of the textile for
adequate dyeing and prevents dripping of water droplets by
condensation on the final color of the dyed textile during
10 steaming in the steam injection unit 112. In an exemplary
embodiment of the present invention, the moisture percentage
of the steaming chambers is maintained in a range of between
25-30% by volume and the temperature of the steaming chambers
is maintained in a range of between 100°C and 130°C and
15 preferably at 120°C. The control unit 110 is configured to
maintain and control the atmosphere of the thermax unit 108.
The control unit 110, which is also referred to as power
unit, acts as an auto-leveler for maintaining the optimum
temperature and moisture conditions in the thermax unit 108.
20 [0022] In an exemplary embodiment of the present invention,
the speed of the CDR machine 100 is maintained at 55 meter
per minute when the RFD textile is fed from the first feeding
unit 102 and until the end of treating of the dyed textile,
which comes out of five chambers to get a dwell time of 2.81
25 minutes and subsequently fed to the wash-off range unit 114.
The said dwell time aids in providing optimized dyeing of
textiles. In an embodiment of the present invention, the dyed
textile from the steam injection unit 112 is fed to the washoff range unit 114 for washing of the dyed textile in order
30 to remove superficial dye color from the dyed textiles. The
operation of the wash-off range unit 114 has been explained
in detail with respect to Fig. 2.
[0023] Fig. 2 illustrates a wash-off range unit 200 (114,
Fig. 1) for washing the dyed textiles, in accordance with an
35 embodiment of the present invention. The wash-off range unit
11
200 comprises a second feeding unit 202, a washing unit 204,
a drum drier unit 206 and a textile batching unit 208. In a
preferred embodiment of the present invention, the wash-off
range unit 200 is maintained in a specified range of speed
5 for allowing a pre-defined dwell time in order to remove all
the unfixed dyes from the dyed textile’s surface.
[0024] In an embodiment of the present invention, the second
feeding unit 202 is fed with the dyed textile from the steam
injection unit 112 (Fig. 1) after steaming and provided to
10 the washing unit 204 of the washing-off range unit 200. In
an exemplary embodiment of the present invention, the washing
unit 204 comprises eight chambers and the dyed textile is
passed through the eight chambers sequentially for washing.
In an embodiment of the present invention, the temperature
15 of water in the washing unit 204 is maintained such that
unfixed dyes are adequately removed from the dyed fabric. The
temperature of the water during washing is maintained by a
steam heating system (not shown). Further, the water in the
washing unit 204 may be mixed with a pH neutral and non-ionic
20 detergent for washing of the dyed textile. Advantageously,
washing of the dyed textile aids in increasing the fastness
of the dye with the dyed textile and increased dye color
retention on the dyed textile.
[0025] In an embodiment of the present invention, the washed
25 dyed textile is fed to the drum drier unit 206 for drying.
The drum drier unit 206 comprises a set of multiple driers,
through which hot air is blown on to the washed dyed textile
for drying of the washed dyed textile. The walls of the dries
are coated with teflon and the teflon coating aids in
30 protecting the heated textile, coming out of the drier unit
206, from receiving a sudden shock due to critical
temperature difference. In an exemplary embodiment of the
present invention, data associated with the dyeing and
washing of the dyed textile is collected and analyzed
35 subsequent to the washing process and used to fine tune the
12
bulk dyeing of the textile. In an embodiment of the present
invention, the dried dyed textile from the drum dried unit
206 is fed to the textile batching unit 208 for collecting
the dyed textile, which is further provided final finishing.
5 In an exemplary embodiment of the present invention,
finishing is provided to the dyed textile using stenter
process, applying natural wax and applying a binder as
finishing agent followed by calendering.

We claim:
1. A process for optimized dyeing of textiles based on a
continuous dyeing mechanism, the process comprises:
padding a Ready for Dye (RFD) textile in a dye liquor,
5 wherein the dyeing liquor is prepared from one or more
natural dye pastes;
squeezing the dyed textile for removing excess dye
liquor from the dyed textile;
wetting the squeezed dyed textile for uniform dyeing;
10 and
steaming the wet dyed textile for fixation of dye on
the dyed textile.
2. The process as claimed in claim 1, wherein the padding of
the Ready for Dye (RFD) textile is carried out in the dye
15 liquor present in a trough placed below a pad mangle unit
(104) in a continuous dyeing range (CDR) machine (100) for
producing the dyed textile.
3. The process as claimed in claim 1, wherein the step of
squeezing the dyed textile is carried out by passing the
20 dyed textile through a pad mangle unit (104) in a CDR
machine (100) for removing excess dye liquor from the dyed
textile.
4. The process as claimed in claim 1, wherein the step of
wetting the squeezed dyed textile is carried out by passing
25 the squeezed dyed textile through an aeration unit (106)
in a CDR machine (100) for uniform dyeing.
5. The process as claimed in claim 1, wherein the step of
steaming the wet dyed textile is carried out by passing
the wet dyed textile through a thermax unit (108) and a
14
steam injection unit (112) in a CDR machine (100) for
fixation of the dye on the dyed textile.
6. The process as claimed in claim 1, wherein the process
comprises:
5 washing the dyed textile by feeding the steamed dyed
textile for removing unfixed dyes from the dyed textile’s
surface;
drying the washed dyed textile; and
batching the dried dyed textile and providing
10 finishing to the dyed textile.
7. The process as claimed in claim 6, wherein the step of
washing the dyed textile is carried out in a washing unit
(204) of a wash-off range unit (114,200) by feeding the
steamed dyed textile through a second feeding unit (202)
15 of the wash-off range unit (114,200) for removing unfixed
dyes from the dyed textile’s surface;
drying the washed dyed textile in a drum drier unit (206)
in the wash-off range unit (114,200); and
batching the dried dyed textile in a textile batching unit
20 (208) in the wash-off range unit (114,200) and providing
the finishing to the dyed textile.
8. The process as claimed in claim 2, wherein speed of the
CDR machine (100) is maintained in a range of between 10
meters and 60 meters per minute.
25 9. The process as claimed in claim 1, wherein the textiles
dyed with the natural dyes comprises woven fabrics, terry
towels and sheeting fabrics.
10. The process as claimed in claim 1, wherein the natural
dyes are derived from plant herbs, and wherein the plant
15
herbs comprise: t.Chebula (haritaki), curcuma longa, rubia
cordifolia, butea monosperma, indigofera tinctoria, iron
vat, paunica granatum, sea salt, areca nut, myrobalan
seeds, sappanwood, lac dye, saw palmetto, bitter orange,
5 rose mary, walnut, henna leaves, aloe vera, champa flower,
neem, cutch, catechu, onion, sandle wood, acacia catechu,
kerria lacca, mulberry tree, tegetas erecta, butea
monosperma, quercus infectoria, rubia cordifolia, plant
punica granatum and a combination thereof.
10 11. The process as claimed in claim 1, wherein the RFD textile
is a pure cotton textile and is pre-treated prior to
dyeing, and wherein pre-treatment of the RFD textile
comprises singeing, enzymatic desizing, scouring cum
bleaching using benninger continuous bleaching range,
15 mercerization using benninger chain mercerization, bio
scouring process, neutralization and drying.
12. The process as claimed in claim 1, wherein the natural dye
pastes are prepared from one or more types of dye powders,
and wherein the dye powders are converted to the dye pastes
20 by mixing with a plant originated natural binder, water
and a natural sea salt.
13. The process as claimed in claim 12, wherein a mordanting
agent is added to the dye paste based on a simultaneous
mordanting process for providing adequate binding property
25 to the natural dyes during the RFD textile dyeing process.
14. The process as claimed in claim 13, wherein the mordanting
agent comprises an iron salt based mordant or an aluminium
salt based mordant or a sea salt based mordant or a
combination thereof.
30 15. The process as claimed in claim 1, wherein the RFD textile
is padded in the dye liquor using a kuster dyeing padding.
16
16. The process as claimed in claim 10, wherein dye colors
obtained from the plant herbs comprises yellow, madder
red, chebula black, brazil brown, cherry pink, bettle
pink, light pink, dark pink, pomo orange, oak brown, woad
5 blue, kassam olive or a combination thereof.
17. The process as claimed in claim 2, wherein pressure in
left, middle and right of the pad mangle unit (104) is
maintained at an optimum level for obtaining a desired
dye liquor pick up value by the dyed textile.
10 18. The process as claimed in claim 17, wherein pressure in
the left, middle and right of the pad mangle unit (104)
is maintained in a range of between 15N to 40N.
19. The process as claimed in claim 5, wherein the steaming
of the wet dyed textile is carried out by passing through
15 the thermax unit (108) and the steam injection unit (112)
comprising five chambers for drying and steaming the dyed
textile.
20. The process as claimed in claim 19, wherein moisture
percentage of the chambers is maintained in a range of
between 25-30% by volume and temperature of the chambers
is maintained in a range of between 100°C and 130°C.
21. The process as claimed in claim 2, wherein dwell time of
the CDR machine (100) is 2.81 minutes.
22. The process as claimed in claim 7, wherein the washing
unit (204) comprises eight chambers, and wherein the dyed
textile is passed through the eight chambers sequentially
for washing.
23. The process as claimed in claim 7, wherein the drum drier
unit (206) comprises a set of multiple driers, and wherein
30 hot air is blown through the driers on to the washed dyed
textile for drying the washed dyed textile.
17
24. The process as claimed in claim 23, wherein walls of the
dries are coated with teflon.
25. The process as claimed in claim 7, wherein the step of
finishing comprises using stenter process, applying
natural wax and applying a binder as a finishing agent
followed by calendaring.
26. The process as claimed in claim 1, wherein the step of
steaming the dyed textile is carried out for a time period
in a range of between 2 minutes and 4 minutes depending
upon the color of the dyed textile.