U.S. patent application number 10/889381 was filed with the patent office on 2005-01-20 for through-dyeing of cotton warp yarns with indigo.
This patent application is currently assigned to DyStar Textilfarben GmbH & Co. Deutschland KG. Invention is credited to Bock, Alexander, Schrott, Wolfgang, Sutsch, Franz.
Application Number | 20050011014 10/889381 |
Document ID | / |
Family ID | 33461943 |
Filed Date | 2005-01-20 |
United States Patent
Application |
20050011014 |
Kind Code |
A1 |
Schrott, Wolfgang ; et
al. |
January 20, 2005 |
Through-dyeing of cotton warp yarns with indigo
Abstract
The present invention relates to a process for through-dyeing of
cotton warp yarns with indigo in an indigo dyeing range, which
comprises dyeing in one pass at a dyeing temperature of 30 to
90.degree. C. and an indigo concentration of 10-60 g/l.
Inventors: |
Schrott, Wolfgang;
(Ludwigshafen, DE) ; Sutsch, Franz;
(Rodersheim-Gronau, DE) ; Bock, Alexander;
(Darmstadt, DE) |
Correspondence
Address: |
CONNOLLY BOVE LODGE & HUTZ, LLP
P O BOX 2207
WILMINGTON
DE
19899
US
|
Assignee: |
DyStar Textilfarben GmbH & Co.
Deutschland KG
Industriepark Hochst/Geb. D706
Frankfurt am Main
DE
65926
|
Family ID: |
33461943 |
Appl. No.: |
10/889381 |
Filed: |
July 12, 2004 |
Current U.S.
Class: |
8/115.51 |
Current CPC
Class: |
D06P 3/6025 20130101;
D06P 1/22 20130101; D06P 1/228 20130101 |
Class at
Publication: |
008/115.51 |
International
Class: |
D06M 010/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2003 |
DE |
DE 103 32 165.9 |
Claims
1. A process for through-dyeing of cotton warp yarns with indigo in
an indigo dyeing range, which comprises dyeing in one pass at a
dyeing temperature of 30 to 90.degree. C. and an indigo
concentration of 5-500 g/l.
2. A process according to claim 1 that utilizes indigo in the form
of a solution of leuco indigo.
3. A process according to claim 2 wherein the leuco indigo has been
produced from indigo by catalytic hydrogenation.
4. A process according to claim 1 wherein the process is further
carried out in the presence of a wetting agent.
5. A process according to claim 4 wherein the wetting agent is used
in amounts of 5 to 50 g/l.
6. A textile article comprising cotton warp yarns dyed by the
process according to claim 1.
7. A process according to claim 3, wherein the process is further
carried out in the presence of a wetting agent.
8. A process according to claim 7, wherein the wetting agent is
used in amounts of 10 to 25 g/l.
9. A process according to claim 1, wherein said indigo
concentration is 10-50 g/l.
10. A process according to claim 1, wherein said indigo is a
pre-reduced indigo.
11. A process according to claim 10, wherein the pre-reduced indigo
is produced from an indigo without the use of a reducing agent.
12. A process according to claim 2, wherein the temperature is from
50 to 70.degree. C.
13. A process according to claim 1, wherein the dyeing is conducted
at a pH from 10.5 to 13.5.
14. A process according to claim 8, wherein the wetting agent is
fatty alcohol ethoxylate, alkanesulfonate, sulfonsuccinate, alkyl
phosphate, paraffin, hydrocarbon or mixtures thereof.
15. A process according to claim 8, wherein the wetting agent is a
salt of phosphoric esters.
Description
[0001] The present invention concerns a process for through-dyeing
of cotton warp yarns with indigo and also textile articles
comprising thus dyed cotton warp yarns.
[0002] Denim refers to a relatively coarse woven cotton fabric
which was originally used for robust workwear, but today is used
particularly for manufacturing fashionable jeans articles. The warp
yarns needed to produce denim can be dyed with indigo or else with
sulfur dyes, especially sulfur black, although dyeing to blue with
indigo is greatly predominant.
[0003] Traditionally, the warp yarn is dyed with indigo as a rope
or as a warp yarn sheet on specific dyeing ranges which consist of
a combination of one or more troughs with squeeze rolls and a
subsequent skying sector. The reduced dye is applied in the troughs
and oxidized in the skying sector (see for example Technical
Information TI/T 017 from BASF AG dated June 1995, title:
Continuous dyeing with indigo). The dyeing is typically carried out
in a dyebath at room temperature or slightly elevated temperatures
of about 20-35.degree. C., a pH of about 10.5 to 14 and an indigo
concentration of about 0.5 to 10 g/l. Wetting agents in a
concentration of about 0.1 to 5 g/l can be used as well. A redox
potential in the dyebath is maintained by using an excess of
hydrosulfite reducing agent in amounts of about 0.1 to 5 g/l. The
yarn contact time with the dyebath is generally 8 to 30 seconds per
pass. Dyeing in multiple passes, i.e., the repeated application of
dye from the dyebath by dipping with subsequent squeezeoff in the
dyeing trough and the following skying, makes it possible to
achieve deeper shades (see for example ITB Veredlung 2/90, title:
Indigo-Frberei: Verfahrens-und maschinentechnische Losungen,
author: Dipl. Ing. L. Haas).
[0004] German Patent Application DE 196 29 985 describes
single-pass dyeing wherein, to overcome the low affinity of indigo,
the dyebath additionally has added to it salt in the form of sodium
chloride in order that an electrolyte concentration of 200 to 350
g/l may be set.
[0005] These processes all produce a so-called ring dyeing, i.e.,
the fiber is dyed at the surface only, leaving the interior of the
fiber, the core, undyed. Ring dyeing makes it possible to endow
made-up denim articles with a high-contrast appearance in
particular washing and/or bleaching processes through a wash-down
of the initially dark blue fabric. An example is the familiar
stone-wash effect, which is achieved by washing the made-up article
with enzymes and pumice stones.
[0006] However, there are already signs that future jeans fashion
will demand effects which cannot be achieved with ring-dyed denim
alone. On the contrary, core-dyed warp yarns have to be available
for the development of new articles if these demands are to be
met.
[0007] The dyeing processes required have to be economical in that
they should not require additional cost and inconvenience on the
part of the dyer, but should be simple to carry out, ideally in a
dyer's existing dyeing equipment.
[0008] The present invention, then, provides such a process.
[0009] The invention relates to a process for through-dyeing of
cotton warp yarns with indigo in an indigo dyeing range, which
comprises dyeing in one pass at a dyeing temperature of 30 to
90.degree. C. and an indigo concentration of 5-500 g/l.
[0010] An indigo dyeing range in the realm of the present invention
is a range which consists of one dyeing trough or a combination of
multiple dyeing troughs with squeeze rolls and subsequent skying
sectors (see for example ITB Veredlung 2/90, title: Indigo-Frberei:
Verfahrens-und maschinentechnische Losungen, author: Dipl. Ing. L.
Haas).
[0011] Any commercially available indigo may be used. Indigo is
preferably used in amounts of 5-500 g/l and more preferably in
amounts of 10 to 50 g/l.
[0012] It is particularly advantageous to use pre-reduced indigo to
carry out the process of the invention. The pre-reduced indigo used
is ideally produced from indigo without use of reducing agent, such
as sodium dithionite for example, but by catalytic hydrogenation.
It is most advantageous to use indigo in the form of a leuco indigo
solution as described for example in EP 1 097 184 B1 and offered on
the market by DyStar Textilfarben GmbH & Co. Deutschland
KG.
[0013] To stabilize leuco indigo, i.e., to back-reduce leuco indigo
which has become oxidized in the dyebath, it is preferable to use a
hydrosulfite excess of 0.1 to 5 g/l and more preferably 0.2 to 2
g/l. It will be appreciated that in lieu of the hydrosulfite it is
possible to use other suitable reducing agents, for example glucose
or hydroxyacetone, or else combinations of various reducing agents
such as glucose/hydrosulfite.
[0014] The temperature at which the process of the invention is
carried out is preferably 30-90.degree. C. and more preferably in
the range from 50 to 70.degree. C.
[0015] The process of the invention can be carried out with or
without wetting agent, but preferably it is carried out in the
presence of a wetting agent. Examples of suitable wetting agents
are anionic wetting agents, for example fatty alcohol ethoxylate,
alkanesulfonate, sulfosuccinate, alkyl phosphate or paraffins and
hydrocarbons or else mixtures thereof, and most preference is given
to using salts of phosphoric esters.
[0016] The amounts in which the wetting agents mentioned are used
are preferably in the range from 5 to 50 g/l and more preferably in
the range from 10 to 25 g/l.
[0017] Dyebath pH in the process of the invention is preferably in
the range from 10.5 to 13.5.
[0018] The process of the invention surprisingly leads in just one
pass to yarns which are through-dyed, i.e., dyed in the core as
well in the surface region. The contact time with the dyebath is
preferably 8 to 30 seconds and more preferably 15 to 20 seconds.
The subsequent skying takes preferably 90 to 130 seconds and more
preferably 100 to 1 10 seconds.
[0019] It is a particular advantage to the dyer that the process of
the invention ends after just one pass. This is because this leaves
the dyer with the option of using the other dyeing troughs of his
indigo dyeing range which are not needed for dyeing to subject the
dyed cotton warp yarn to further treatment steps. Alternatively,
the dyer also has the option of course of realizing more
economical, small-scale ranges.
[0020] The process of the invention is particularly surprising
because the properties of indigo did not suggest that the use of
high indigo levels leads to a satisfactory dyed result. On the
contrary, it had hitherto been assumed that the large indigo dyeing
ranges of the prior art are indispensable for this purpose.
[0021] The core-dyed cotton warp yarns dyed in the core by the
process of the invention can be subjected to further treatment
steps to obtain certain effects and then be conventionally woven up
and processed into textile articles for the consumer, such as
garments in particular.
[0022] However, it is also possible for the dyed cotton warp yarns
to be processed into textile articles without further treatment
and, if desired, only then to undertake further treatment steps,
i.e., to modify the already made-up merchandise.
[0023] It is of course similarly possible to subject not only the
dyed cotton warp yarns but also the textile articles produced
therefrom to further processing steps.
[0024] The cotton warp yarns dyed by the process of the invention
can of course also be woven up, and further processed into articles
for the consumer, in admixture with further materials. Blends with
elastane may be mentioned by way of example.
[0025] The present invention also provides textile articles
comprising cotton warp yarns dyed by the process of the invention.
Examples of such textile articles are denim fabrics which have not
been made up, but in particular garments such as pants, skirts,
shirts, jackets, etc. or other textile type articles.
[0026] The examples which follow illustrate the invention. The
parts in the table examples are by weight.
EXAMPLE 1
[0027] A commercially available unpretreated dry cotton warp yarn
was dyed from a dyeing liquor of the following composition:
[0028] 20 g/l of indigo as commercially available DyStar Indigo Vat
40% solution
[0029] 2 g/l of hydrosulfite (BASF Hydrosulfit konz.)
[0030] 20 g/l of wetting agent (Primasol NF)
[0031] The pH of the liquor was 13.
[0032] The yarn was dyed at 50.degree. C. in the course of a dip
time of 25 seconds. The subsequent skying took 120 seconds.
[0033] This was followed by two rinses with water at 20.degree.
C.
[0034] A through-dyed yarn having a high level of applied indigo
was obtained. A dye analysis of the dyed yarn revealed a level of
5.8%.
EXAMPLE 2
[0035] A commercially available unpretreated dry cotton warp yarn
(yarn count: 8.5 Ne, 24 per rope) was dyed from a dyeing liquor of
the following composition:
[0036] 25 g/l of indigo as commercially available DyStar Indigo Vat
40% solution
[0037] 5 g/l of hydrosulfite (BASF Hydrosulfit konz.)
[0038] 25 g/l of wetting agent (Primasol NF)
[0039] The pH of the liquor was 12.6.
[0040] The yarn was dyed at 60.degree. C. in the course of a dip
time of 10 seconds. The subsequent skying took 120 seconds. The
yarn throughput was 12.61 kg/min.
[0041] This was followed by two rinses with water at 20.degree.
C.
[0042] A through-dyed yarn having a high level of applied indigo
was obtained. A dye analysis of the dyed yarn revealed a level of
6%.
[0043] The table examples which follow describe further embodiments
of the process of the invention. They are carried out similarly to
the abovementioned examples 1 and 2. A through-dyed yarn having a
high level of applied indigo is obtained in each case.
1 Product Example 3 Example 4 Example 5 Example 6 Example 7 Example
8 DyStar Indigo Vat 100 450 200 120 40% solution DyStar Indigo Vat
35 60% grains DyStar Indigo granules 80 Hydrosulfite conc. (BASF) 5
70 1 10 Glucose 10 20 20 2 Fatty alcohol ethoxylate 10 and
alkanesulfonate Sulfosuccinate Paraffins, hydrocarbons 30 and fatty
alcohol ethoxylate Alkyl phosphate 20 20 10 Fatty alcohol
ethoxylate and alkyl phosphates pH 13 11.8 12.8 13 12.4 11.0
Temperature (.degree. C.) 50 80 90 70 50 70 Number of passes 1 1 1
1 1 1
* * * * *