U.S. patent application number 16/618588 was filed with the patent office on 2020-05-21 for low temperature colouring method.
The applicant listed for this patent is UNIVERSITY OF LEEDS. Invention is credited to Stephen Martin BURKINSHAW.
Application Number | 20200157737 16/618588 |
Document ID | / |
Family ID | 62563190 |
Filed Date | 2020-05-21 |
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United States Patent
Application |
20200157737 |
Kind Code |
A1 |
BURKINSHAW; Stephen Martin |
May 21, 2020 |
LOW TEMPERATURE COLOURING METHOD
Abstract
The present invention relates to a method of colouring polymer
substrates at low temperatures. The method comprises subjecting the
polymer substrate that is to be coloured to a colouring liquor
comprising a solvent in which the colourant has a high solubility
and then adding a solvent in which the colourant has a low
solubility, typically water.
Inventors: |
BURKINSHAW; Stephen Martin;
(Leeds, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNIVERSITY OF LEEDS |
Leeds, West Yorkshire |
|
GB |
|
|
Family ID: |
62563190 |
Appl. No.: |
16/618588 |
Filed: |
May 31, 2018 |
PCT Filed: |
May 31, 2018 |
PCT NO: |
PCT/GB2018/051480 |
371 Date: |
December 2, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06P 3/60 20130101; D06P
3/143 20130101; D06P 3/54 20130101; D06P 3/8238 20130101; D06P
1/0032 20130101; D06P 1/928 20130101; D06P 2001/906 20130101; D06P
3/8233 20130101; D06P 3/045 20130101 |
International
Class: |
D06P 1/92 20060101
D06P001/92; D06P 1/00 20060101 D06P001/00; D06P 3/54 20060101
D06P003/54; D06P 3/82 20060101 D06P003/82; D06P 3/14 20060101
D06P003/14; D06P 3/04 20060101 D06P003/04; D06P 3/60 20060101
D06P003/60 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2017 |
GB |
1708816.2 |
Apr 26, 2018 |
GB |
1806803.1 |
Claims
1. A method of colouring a polymer substrate, the method
comprising: a) subjecting the polymer substrate to a colouring
liquor at a temperature T1, T1 being below 100.degree. C., said
colouring liquor comprising at least one colourant dissolved in a
first solvent system to provide the polymer substrate wetted with
the colouring liquor; b) adding a second solvent system to the
polymer substrate wetted with the colouring liquor, without raising
the temperature above a temperature T2, T2 being below 100.degree.
C., to provide the coloured polymer substrate wetted with a mixture
of the first solvent system and the second solvent system; and c)
separating the coloured polymer substrate from the mixture of the
first and second solvent systems and any remaining colourant;
wherein the colourant or colourant dye is more soluble in the first
solvent system than in the second solvent system.
2. (canceled)
3. (canceled)
4. A method of claim 1, wherein the second solvent system is
water.
5. A method of claim 1, wherein the first solvent system and the
second solvent system are miscible.
6. (canceled)
7. A method of claim 1, wherein the first solvent system is a polar
organic solvent or a mixture of polar organic solvents.
8. A method of claim 7, wherein the first solvent system comprises
acetone.
9. A method of claim 7, wherein the first solvent system comprises
a solvent selected from glycerol, ethylene glycol diacetate (EGD),
triethylene glycol monomethyl (TGM), dipropylene glycol methyl
ether (DME) and 1-methoxy-2-propanol.
10. A method of claim 1, wherein the polymer substrate is a fibre
substrate.
11. A method of claim 10, wherein the fibre substrate comprises
fibres selected from: a polyester, nylon, a polyurethane, wool,
silk, cotton or a mixture thereof.
12. A method of claim 11, wherein the fibre substrate comprises
polyester fibres.
13. A method of claim 12, wherein the fibre substrate comprises
polyester fibres and at least one fibre selected from cotton,
regenerated cellulose, wool, silk, polyamide, a different
polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere
and a polyurethane.
14. A method of claim 13, wherein the fibre substrate comprises a
material that is a blend of polyester fibres and at least one fibre
selected from cotton, regenerated cellulose, wool, silk, polyamide,
a different polyester, polyvinylchloride, polyacrylonitrile,
mohair, cashmere and a polyurethane.
15. A method of claim 14, wherein the fibre substrate comprises a
first material that comprises polyester fibres and a second
material that comprises at least one fibre selected from cotton,
regenerated cellulose, wool, silk, polyamide, a different
polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere
and a polyurethane.
16. A method of claim 15, wherein the fibre substrate is a whole
garment.
17. A method of claim 1, wherein the ratio of the total volume of
the first solvent system to the total volume of the second solvent
system is in the range 1:2 to 1:20.
18. A method of claim 16, wherein the ratio of the total volume of
the first solvent system to the total volume of the second solvent
system is in the range 30:70 to 10:90.
19. A method of claim 1, wherein the weight ratio of the polymer
substrate to the first solvent system is in the range from 3:1 to
1:3.
20. A method of claim 1, wherein the at least one colourant is at
least one dye.
21. A method of claim 20, wherein the at least one dye is a
disperse dye.
22. A method of claim 1, wherein the method comprises dissolving
the at least one colourant in the first solvent system to form the
colouring liquor
23. A method of claim 1, wherein the colouring liquor does not
comprise a dispersing agent.
24. (canceled)
Description
[0001] The present invention relates to a method of colouring
polymer substrates at low temperatures. The method comprises
subjecting the polymer substrate that is to be coloured to a
colouring liquor comprising a solvent in which the colourant has a
high solubility and then adding a solvent in which the colourant
has a low solubility, typically water. The method is particularly
useful for dyeing polyester fibres and polyester fibre blends with
disperse dyes.
BACKGROUND
[0002] A large proportion of the textile products produced in the
world today comprise polyesters. In particular poly(ethylene
terephthalate) (PES) accounted for .about.58.5%
(53.1.times.10.sup.6 T) of the 90.6.times.10.sup.6 T world textile
fibre demand in 2015. The outstanding success and enduring
popularity of PES fibres can be attributed to their generally
excellent textile characteristics and high chemical resistance,
coupled with the ability of polyester fibre to be manufactured in
virtually any physical form as required for different applications,
which include blending with other types of fibre. In the latter
context, a chief use of polyester fibres is in combination with
cotton fibres. In such polycotton blend materials, the cotton
component provides comfort, absorbency, etc. whilst the polyester
constituent imparts strength and resilience as well as
stain-resistance.
[0003] Polyester fibres are dyed exclusively using disperse dyes,
which furnish a wide shade gamut and display generally very good
fastness properties on polyester. Disperse dyes belong to several
chemical classes, predominantly anthraquininoid, (AQ), and azo, as
exemplified by C.I. Disperse Red 60 and C.I. Disperse Blue 165.
##STR00001##
[0004] Disperse dyes typically have low aqueous solubility.
Solubility increases, however, markedly with increasing
temperature, as exemplified by C.I. Disperse Red 121: 3.3 0.00033
gL.sup.-1 at 25.degree. C.; 0.0088 gL.sup.-1 at 130.degree. C. This
is of significance for their application to polyester fibre under
High Temperature (HT) dyeing conditions.
[0005] The solubility of disperse dyes is greatly increased in the
presence of commercial dispersing agents, a feature that forms the
basis of both the finishing process that is used to prepare
commercial forms of the dye and the application method that is
employed in their application to polyester fibres under aqueous
immersion processes. Commercial disperse dyes typically comprise up
to 60% by mass dispersing agent, adding considerably to the cost of
the dyes. Dispersing agents (examples include lignin sulfonates or
formaldehyde polycondensates or arylsulfonic acids) are not
particularly environmentally friendly. The removal and disposal of
such materials from the dyed textile fibre at the end of dyeing
adds considerably to the cost, energy efficiency and environmental
risk of commercial dyeing.
[0006] Owing to the very low rate of diffusion of the dyes within
PES fibres at temperatures up to the commercial boil (i.e.
98.degree. C.), commercially acceptable rates of dyeing with
disperse dyes are most commonly achieved by the use of elevated
temperatures in the region of 130-140.degree. C. in a process
commonly referred to as High Temperature (HT) dyeing. Currently,
the vast majority of polyester fibre is dyed using such immersion
processes at 130-140.degree. C. Because such high temperatures are
required for dyeing, the dyeing process is energy-intensive and the
machines that are utilised for dyeing must be able to operate at
pressures >1 atmosphere; consequently, the machines are
typically very expensive.
[0007] PES fibres contain small amounts of oligomer, principally
the cyclic trimer tris(ethylene terephthalate), as well as smaller
amounts of other oligomeric compounds. Such compounds migrate to
the fibre surface during HT dyeing and can deposit on the surfaces
of both the fibre and machine during cooling, which can reduce the
visual depth of shade brilliance of dyeings; the removal of the
compounds from the dyeing machine constitutes an additional problem
in immersion dyeing. The removal of the oligomers, in addition to
the excess dye and the dispersing agents, is routinely achieved
using a reduction clearing process in which the dyed material is
treated with Na.sub.2S.sub.2O.sub.4 and a non-ionic surfactant,
typically with heating. This process adds additional time to the
process as well as additional materials and energy. It also
generates environmentally unacceptable efluents, including
Na.sub.2S.sub.2O.sub.4 and, in the case of azo-disperse dyes,
aromatic amines biproducts.
[0008] A further limitation of HT dyeing methods is that many
fabrics, and particularly natural fabrics (e.g. wool, silk) and
more sensitive manmade fabrics (e.g. polyurethanes, for example,
Lycra.RTM.) are not stable under the high temperature conditions.
Where polyesters are combined (either woven together as a blend or
joined together as parts of a garment) with these materials, other
less effective dyeing methods must be used (which can lead to
discernible differential colour strengths for the individual
fabrics in the blend) or pre-dyed fabric must be blended, which is
a complex and costly process. This means that for blends or
garments that are formed of more than one different material, the
fibres have to be dyed separately before being woven together or
joined together.
[0009] When PES was first introduced in the 1950s, the preferred
dyeing method used was carrier dyeing, in which a carrier,
typically a low molar mass, solid organic compound, such as
o-phenyl phenol, is included in the aqueous dyeing liquor. This
carrier facilitates the dyeing of the fabric and allows the use of
lower temperatures than HT dyeing, typically 98.degree. C. However,
the carriers often have detectable smells, they often impair the
light fastness of the dyed material and they also pose
environmental concerns and, as a result, HT dyeing processes
predominate commercially nowadays and the use of carrier dyeing has
steadily declined.
[0010] Disperse dyes are much more soluble in organic solvents than
they are in water. However, organic solvents are ineffective for
disperse dyeing because the dye has a greater affinity for the
solvent than it does for the fibres. Consequently, when disperse
dyes are applied from organic solvents low dye uptake onto the
fibres is achieved so that the depth of shade that can be accessed
using high temperature aqueous dyeing techniques cannot be
replicated using organic solvent based dyeing liquors.
[0011] It is not just in the dyeing of polyesters where
improvements in dyeing can be made. Methodologies for dyeing wool,
silk and polyamide fibres are often carried out at high
temperatures and usually require specific values of pH for their
successful application, leading to the use of additional chemicals
to control the pH. The methods can also be time consuming. For
example, dyeing with vat dyes is a complicated, time-consuming,
multi-stage process that involves several pH changes and requires
the use of environmentally questionable strong reducing agents.
[0012] In addition, dyeing auxiliaries are commonly used to assist
aqueous immersion dyeing processes. The assistance provided by a
given dyeing auxiliary will typically relate to a specific aspect
of dyeing, such as wetting, dye levelling, fibre protection, etc.
Thus, many different types of dyeing auxiliary are commonly used in
aqueous dye application, such as dispersants, sequestrants,
lubricants, etc.). For example, dyeing processes for polyester
fibres typically utilise dispersing agents and surfactants which
are added to the dyebath to aid dye dispersion and levelling, as
discussed above. Also, the pH at which dyeing is performed is
commonly adjusted so as to be within a defined range, such as
slightly acidic (pH.about.4.5-6.0), although selected disperse dyes
are suitable for application at high pH (.about.pH 9.5). Because
aqueous dyebaths routinely contain many auxiliaries often in large
amounts, the wastewater generated during immersion dyeing is likely
to contain a wide variety of auxiliary chemicals; indeed, many of
the auxiliaries that are utilised in immersion dyeing (such as s
dispersing agents that are used in polyester dyeing) are intended
to be removed from the dyed material at the end of dyeing, meaning
that such chemicals will be present in the wastewater that ensues
from dyeing processes. Although many strategies have been explored
for treating dyeing effluent that contains residual dyeing
auxiliaries, no single treatment method is effective for all
auxiliaries or types of dye/fibre system. An additional advantage
of certain embodiments of the current invention is that it is
possible to reduce the number and amount of dyeing auxiliaries that
are used in dyeing processes, thus offering savings in chemical
costs as well as environmental advantages.
[0013] Although, the methods of the invention were developed for
the dyeing of fibre substrates, the inventors have found that they
can be applied more generally to other polymer substrates.
BRIEF SUMMARY OF THE DISCLOSURE
[0014] In a first aspect of the invention is provided a method of
colouring a polymer substrate, the method comprising: [0015] a)
subjecting the polymer substrate to a colouring liquor at a
temperature T1, T1 being below 100.degree. C., said colouring
liquor comprising at least one colourant dissolved in a first
solvent system to provide the polymer substrate wetted with the
colouring liquor; [0016] b) adding a second solvent system to the
polymer substrate wetted with the colouring liquor, without raising
the temperature above a temperature T2, T2 being below 100.degree.
C., to provide the dyed polymer substrate wetted with a mixture of
the first solvent system and the second solvent system; and [0017]
c) separating the dyed polymer substrate from the mixture of the
first and second solvent systems and any remaining colourant;
wherein the colourant or each colourant is more soluble in the
first solvent system than in the second solvent system.
[0018] The polymer substrate may be a fibre substrate. The
colourant may be a dye. The inventors have found that greater depth
of colour can be achieved using the same quantity of colourant when
using the above method than can be achieved using HT disperse
dyeing methods. This greater depth of colour is achieved at a lower
temperature than used in conventional HT methods and it is not
necessary to use dispersing agents. Thus, the method of the first
aspect is likely to be less energy intensive, less costly and pose
lower risk to the environment than known HT methods. Also being a
low temperature process it can be performed on or in the presence
of sensitive natural and man-made fibres. Without wishing to be
bound by theory, it is believed that the addition of the second
solvent system to the solution of the colourant in the first
solvent system lowers the solubility of the colourant in the
solvents. This in turn generates a molecular dispersion from which
uptake of the colourant into the fibre is possible and indeed that
is more favoured than with the dispersions formed in HT dyeing
methods.
[0019] The inventors also have found that when applied to the acid
dyeing of certain substrates, the methods of the invention provide
effective dyeing without the use of added dyeing auxiliaries, at
lower temperatures and more quickly than traditional methods.
[0020] The lower temperatures used allow for the simultaneous
colouring of more than one polymer type at a time. The methods
apply not just to disperse dyes but also to other types of
colourant, including acid dyes, direct dyes, reactive dyes and vat
dyes. The inventors have shown that it is possible to dye more than
one polymer (e.g. fabric) type at a time using the methods of the
invention, with different colourant being simultaneously used to
colour different polymers (e.g. fabrics).
[0021] In a second aspect of the invention is provided a polymer
(e.g. fibre) substrate obtainable (e.g. obtained) according to the
method of the first aspect.
The Method
[0022] It may be that the total amount of the second solvent system
is added as a single portion to the polymer (e.g. fibre) substrate
wetted with the colouring liquor. It may be that it is added
continuously over a predetermined period of time. It may be that it
is added portionwise. Thus, it may be that the total amount of the
second solvent system is added in a predetermined number of equal
sized portions, a predetermined period of time apart. The inventors
have found that the portionwise addition of the second solvent
system provides the most effective colouring. Without wishing to be
bound by theory, it is believed that the portionwise addition
provides a more controlled formation of the molecular dispersion of
the colourant (e.g. dye). In certain embodiments, the inventors
have observed 100% uptake of the colourant into the substrate,
leaving no colourant left in the resultant mixture of the first
solvent system and the second solvent system.
[0023] The second solvent system is added to cause the colourant to
precipitate out of the colouring liquor. Typically, where the
polymer substrate is a fibre substrate, this precipitation will
occur within the fibre substrate
[0024] The number of equal sized portions of the second solvent
system may be in the range from 2 to 10, e.g. in the range from 3
to 6.
[0025] The dyed polymer (e.g. fibre) substrate wetted with a
mixture of the first solvent system and the second solvent system
may be held at a temperature T3, T3 being below 100.degree. C., for
a predetermined period of time after the addition of the second
solvent system
[0026] Typically, the coloured (e.g. dyed) polymer (e.g. fibre)
substrate wetted with a mixture of the first solvent system and the
second solvent system will be cooled or allowed to cool to a
temperature T4 before the coloured (e.g. dyed) polymer (e.g. fibre)
substrate is separated from the mixture of the first and second
solvent systems and any remaining dye.
[0027] It may be that the total colouring (e.g. dyeing) time is
less than 3 hours. It may be that the total colouring (e.g. dyeing)
time is less than 90 minutes. It may be that the total colouring
(e.g. dyeing) time is less than 45 minutes. It may be that the
total colouring (e.g. dyeing) time is greater than 20 minutes. The
total colouring (e.g. dyeing) time is the period of time from the
first addition of the second solvent system to the cooling of the
dyed polymer (e.g. fibre) substrate wetted with a mixture of the
first solvent system and the second solvent system.
[0028] It may be that the step of subjecting the polymer (e.g.
fibre) substrate to a colouring liquor involves spraying the
colouring liquor onto the substrate (e.g. fibre) substrate. It may
be that the step of subjecting the polymer (e.g. fibre) substrate
to a colouring liquor involves placing the substrate into the
colouring liquor.
[0029] It may be that the step of adding the second solvent system
to the polymer (e.g. fibre) substrate wetted with the colouring
liquor involves spraying the second solvent system onto the polymer
(e.g. fibre) substrate wetted with the colouring liquor. It may be
that the step of adding the second solvent system to the polymer
(e.g. fibre) substrate wetted with the colouring liquor involves
adding the second solvent system into a colouring liquor in which
the substrate is located.
[0030] The method may comprise the step of dissolving the colourant
(e.g. dye) in the first solvent system to form the colouring
liquor.
[0031] It may be that the colouring liquor does not comprise a
dispersing agent. Typical dispersing agents include anionic,
polyelectrolyte, compounds (and mixtures thereof), such as lignin
sulfonates or formaldehyde polycondensates of arylsulfonic acids
(e.g. disodium methylenebisnaphthalene sulfonate, sodium
oleyl-p-anisidinesulfonate). It may be that the dyeing liquor does
not comprise a carrier. Typical carriers include, for example,
o-dichlorobenzene, 1,2,4-trichlorobenzene, dimethyl phthalate,
diallyl phthalate, o-phenyl phenol, p-phenyl phenol, diphenyl,
1-methylnaphthalene, ethylene carbonate and propylene carbonate.
Thus, the colouring liquor may consist essentially of the at least
one colourant (e.g. a dye, for example a disperse dye) dissolved in
the first solvent system (e.g. a polar organic solvent). Thus,
where the invention comprises the step of dissolving the colourant
(e.g. dye) in the first solvent system to form the colouring
liquor, the colourant (e.g. dye) that is dissolved may be
substantially pure (e.g. greater than 90% or greater than 95%
pure). The inventors have found that excellent colour strength can
be obtained using the method of the invention in the absence of a
dispersing agent or a carrier.
[0032] It may be that the second solvent system does not comprise a
dispersing agent. It may be that the second solvent system does not
comprise a carrier. Thus, the second solvent system may consist
essentially of the solvent or solvents that form the second solvent
system.
[0033] Alternatively, the colouring liquor and/or the second
solvent system may comprise at least one additive selected from: a
dispersing agent, a carrier, a stabiliser, a surfactant, an
antioxidant, a pH modifier/buffer, lubricant, softener, hydrotope,
wetting agent and migrating agent. The colouring liquor and/or the
second solvent system may comprise at least one additive selected
from: a stabiliser, a surfactant, an antioxidant, a pH
modifier/buffer, lubricant, softener, hydrotope, wetting agent and
migrating agent.
[0034] T1 and T2 may be the same. T1, T2 and T3 may be the
same.
[0035] T1 may be greater than 70.degree. C. T1 may be greater than
80.degree. C. T1 may be greater than 90.degree. C.
[0036] T2 may be greater than 70.degree. C. T2 may be greater than
80.degree. C. T2 may be greater than 90.degree. C.
[0037] T3 may be greater than 70.degree. C. T3 may be greater than
80.degree. C. T3 may be greater than 90.degree. C.
[0038] T4 may be less than 70.degree. C. T4 may be less than
60.degree. C.T1 may be in the range 25.degree. C. to 70.degree. C.
T2 may be in the range 25.degree. C. to 70.degree. C. T2 may be in
the range 25.degree. C. to 70.degree. C. Certain types of
colourant, and particularly dyes used to colour natural fibres,
such as, wool, silk and cotton, can be used effectively at
temperatures below 70.degree. C. using the methods of the
invention.
[0039] The method may be conducted at a pressure of about 1 atm.
The method may be conducted at a pressure in the range from 0.9 atm
to 1.5 atm. The method may be conducted at an elevated pressure,
e.g. a pressure greater than 1 atm and up to 5 atm.
[0040] It may be that the weight ratio of the polymer (e.g. fibre)
substrate to the first solvent system is in the range from 4:1 to
1:4. It may be that the weight ratio of the polymer (e.g. fibre)
substrate to the first solvent system is in the range from 3:1 to
1:3. It may be that the weight ratio of the polymer (e.g. fibre)
substrate to the first solvent system is in the range from 2:1 to
1:2.5. It may be that the weight ratio of the polymer (e.g. fibre)
substrate to the first solvent system is in the range from 1:1 to
1:2. It may be that the weight ratio of the polymer (e.g. fibre)
substrate to the first solvent system is in the range from 1:0.1 to
1:15.
[0041] It may be that the ratio of the polymer (e.g. fibre)
substrate to the total amount of the second solvent system is in
the range from 3:1 to 1:15. It may be that the weight ratio of the
polymer (e.g. fibre) substrate to the total amount of the second
solvent system is in the range from 2:1 to 1:10. It may be that the
weight ratio of the polymer (e.g. fibre) substrate to the total
amount of the second solvent system is in the range from 1:1 to
1:4.
[0042] It may be that the weight ratio of the polymer (e.g. fibre)
substrate to the total amount of the first and second solvent
systems is in the range from 1:1 to 1:20. It may be that the weight
ratio of the polymer (e.g. fibre) substrate to the total amount of
the first and second solvent systems is in the range from 1:1 to
1:10. It may be that the weight ratio of the polymer (e.g. fibre)
substrate to the total amount of the first and second solvent
systems is in the range from 1:2 to 1:5.
[0043] It may be that the amount of colourant (e.g. dye) used is in
the range from 0.5 to 10% of the mass of the polymer substrate
(e.g. 0.5 to 10% on mass fibre). It may be that the amount of
colourant (e.g. dye) used is in the range from 1 to 5% of the mass
of the polymer substrate (e.g. 1 to 5% on mass fibre).
[0044] Typically, the total volume of the first solvent system to
which the polymer (e.g. fibre) substrate is subjected is less than
the total volume of the second solvent system to which the polymer
(e.g. fibre) substrate is subjected. The ratio of the total volume
of the first solvent system to the total volume of the second
solvent system may be in the range 1:2 to 1:20. The ratio of the
total volume of the first solvent system to the total volume of the
second solvent system may be in the range 1:3 to 1:15. The ratio of
the total volume of the first solvent system to the total volume of
the second solvent system may be in the range 30:70 to 10:90.
[0045] The colouring process may be followed by reduction clearing,
rinsing and optionally further treatments depending on the nature
of the substrate (e.g. whether the substrate is a single or
multicomponent blend of fibres), and end-use requirement. Exemplary
further treatments include softening, heat setting, etc.
The Solvent Systems
[0046] The methods of the invention involve the use of two solvent
systems. The colourant (e.g. dye) is more soluble in the first
solvent system than it is in the second solvent system.
[0047] The first solvent system should be capable of dissolving at
least one colourant.
[0048] The first solvent system may be supercritical CO.sub.2. The
first solvent system may be a surfactant (e.g. a polyethoxylated
fatty acid or and fatty acid ester or a mixture thereof) or a
solution of a surfactant in water.
[0049] Preferably, however, the first solvent system may comprise
an organic solvent or a mixture of two or more organic solvents.
The first solvent system may be an organic solvent or a mixture of
two or more organic solvents. The first solvent system may be an
organic solvent. The first solvent system may comprise a mixture of
two or more organic solvents. Where the first solvent system
comprises an organic solvent or a mixture of two or more organic
solvents, the inventors have shown that the presence of water is
tolerated in the first solvent system but, typically, the first
solvent system may comprise water but the water will typically
represent less than 50% (e.g. less than 10%) by total weight of the
first solvent system. Thus, the first solvent system may comprise
less than 5% (e.g. less than 1%) water. The first solvent system
may comprise a mixture of water and an organic solvent.
[0050] The first solvent system may be an organic solvent having a
molecular weight below 200 or a mixture of two or more organic
solvents each having a molecular weight below 200. The first
solvent system may be an organic solvent having a molecular weight
below 175 or a mixture of two or more organic solvents each having
a molecular weight below 175. The first solvent system may be an
organic solvent having a molecular weight below 150 or a mixture of
two or more organic solvents each having a molecular weight below
150. The first solvent system may be an organic solvent having a
molecular weight below 120 or a mixture of two or more organic
solvents each having a molecular weight below 120. The first
solvent system may be an organic solvent having a molecular weight
below 100 or a mixture of two or more organic solvents each having
a molecular weight below 100. The first solvent system may be an
organic solvent having a molecular weight below 80 or a mixture of
two or more organic solvents each having a molecular weight below
80. The first solvent system may be an organic solvent having a
molecular weight above 80 or a mixture of two or more organic
solvents each having a molecular weight above 80.
[0051] The first solvent may be an organic solvent that is a liquid
at 25.degree. C. and 1 atm or a mixture of two or more organic
solvents each of which is a liquid at 25.degree. C. and 1 atm. The
first solvent may be an organic solvent that is a liquid at
0.degree. C. and 1 atm or a mixture of two or more organic solvents
each of which is a liquid at 0.degree. C. and 1 atm.
[0052] The first solvent system may be selected from: a non-polar
organic solvent (examples include pentane, hexane, benzene,
toluene, dichloromethane, cyclohexane, heptane, CCl.sub.4 etc), a
polar aprotic solvent (e.g. acetone, methyl-t-butylketone,
N-methylpyrollidinone, N,N-dimethylformamide,
N,N-dimethylacetamide, tetrahydrofuran, diethylether, ethylacetate,
dimethylsulfoxide, diethylene glycol diethyl ether, ethylene glycol
diacetate etc.) and a protic polar solvent (e.g. ethanol, methanol,
propanol, isopropanol, ethylene glycol, glycerol, triethylene
glycol monomethyl ether, dipropylene glycol methyl ether,
1-methoxy-2-propanoletc) or a mixture thereof. The first solvent
system may comprise a polar organic solvent or a mixture of two or
more polar organic solvents. The first solvent system may be a
polar organic solvent or a mixture of two or more polar organic
solvents. The first solvent system may comprise a polar aprotic
organic solvent or a mixture of two or more polar aprotic organic
solvents. The first solvent system may be an organic solvent
comprising an ether group or a mixture of two or more organic
solvents comprising an ether group. The first solvent system may be
an organic solvent comprising both an ether group and a hydroxy
group or a mixture of two or more organic solvents comprising both
an ether group and a hydroxy group. The first solvent system may be
a polar aprotic organic solvent or a mixture of two or more polar
aprotic organic solvents. The first solvent system may comprise an
organic solvent that comprises carbon, hydrogen, oxygen, nitrogen
and sulphur or a mixture of two or more organic solvents that
comprise carbon, hydrogen, oxygen, nitrogen and sulphur. The first
solvent system may comprise an organic solvent that comprises
carbon, hydrogen and oxygen or a mixture of two or more organic
solvents that comprise carbon, hydrogen and oxygen.
[0053] The first solvent system may comprise acetone. The first
solvent system may be acetone. The first solvent system may be a
mixture of acetone and one or more other polar organic solvent,
e.g. a mixture of acetone and ethanol.
[0054] The first solvent system may comprise DMSO. The first
solvent system may be DMSO. The first solvent system may be a
mixture of DMSO and one or more other polar organic solvent, e.g. a
mixture of DMSO and ethanol or a mixture of DMSO and acetone.
[0055] The first solvent system may comprise glycerol. The first
solvent system may be glycerol. The first solvent system may be a
mixture of glycerol and one or more other polar organic solvent,
e.g. a mixture of acetone and glycerol.
[0056] The first solvent system may comprise a solvent selected
from ethylene glycol diacetate, triethylene glycol monomethyl
ether, dipropylene glycol methyl ether and 1-methoxy-2-propanol.
The first solvent system may be a solvent selected from ethylene
glycol diacetate, triethylene glycol monomethyl ether, dipropylene
glycol methyl ether and 1-methoxy-2-propanol or a mixture
thereof.
[0057] The first solvent system may comprise a solvent selected
from glycerol, ethylene glycol diacetate, triethylene glycol
monomethyl ether, dipropylene glycol methyl ether and
1-methoxy-2-propanol. The first solvent system may be a solvent
selected from glycerol, ethylene glycol diacetate, triethylene
glycol monomethyl ether, dipropylene glycol methyl ether and
1-methoxy-2-propanol or a mixture thereof.
[0058] The second solvent system should be one in which the
colourant (e.g. dye) is poorly soluble. The second solvent system
may be an organic solvent in which the colourant (e.g. dye) is less
soluble than the colourant (e.g. dye) is in the first solvent
system. Typically, the second solvent system comprises water. The
second solvent system may be water or an aqueous solution. The
second solvent system may be a mixture of water or an aqueous
solution and an organic solvent. The second solvent system may be
water. The second solvent may comprise a mixture of two or more
organic solvents.
[0059] Where the second solvent system is an aqueous solution it
may be a solution of an electrolyte, an acid, a base or a buffer or
a mixture of an electrolyte with an acid, a base or a buffer.
[0060] Suitable electrolytes include NaCl, Na.sub.2SO.sub.4,
ammonium sulfate and others that are commonly used in the
application of dyes by dyeing.
[0061] Suitable bases include Na.sub.2CO.sub.3, NaHCO.sub.3,
K.sub.2CO.sub.3, KOH, NaOH and others that are commonly used in the
application of dyes by dyeing. Suitable acids include acetic acid,
formic acid, and others that are commonly used in the application
of dyes by dyeing.
[0062] Suitable buffers include those based upon citrate,
phosphate, acetate and others that are commonly used in the
application of dyes by dyeing.
[0063] Electrolytes are particularly useful when using a reactive
dye, a vat dye or a direct dye.
[0064] Bases are particularly useful when using a reactive dye.
[0065] It may be that the first solvent system is miscible with the
second solvent system. Thus, where the second solvent system is or
comprises water, the first solvent system may be water
miscible.
[0066] Both the first and second solvent system are typically
selected such that the polymer (e.g. fibre) substrate is not
soluble in either the first or second solvent system.
[0067] Typically, the total volume of the first solvent system to
which the polymer (e.g. fibre) substrate is subject is less than
the total volume of the second solvent system to which the polymer
(e.g. fibre) substrate is subjected. The ratio of the total volume
of the first solvent system to the total volume of the second
solvent system may be in the range 1:1.1 to 1:10. The ratio of the
total volume of the first solvent system to the total volume of the
second solvent system may be in the range 1:2 to 1:20. The ratio of
the total volume of the first solvent system to the total volume of
the second solvent system may be in the range 1:3 to 1:15. The
ratio of the total volume of the first solvent system to the total
volume of the second solvent system may be in the range 30:70 to
10:90.
The Substrate
[0068] The polymer substrate may comprise natural, man-made and/or
synthetic polymers of organic or inorganic derivation, including,
polypeptides, polysaccharides, hydrocarbons, elastomers, thermosets
and thermoplastics, as exemplified by, but not limited to, polymers
such as collagen, keratin, cellulosics, alginates, polysulfide,
polyamide, poly(lactic acid), polyvinyl chloride,
polyacrylonitrile, polyethylene, polypropylene, polystyrene,
polyurethane, aramid and polyimide.
[0069] The polymer substrate may take any solid physical form,
including powder, pellet, sheet, film, fibre or any irregular
shape. The polymer substrate may be a moulded plastic shape, e.g. a
car bumper or a pair of spectacles. The polymer substrate may be a
3D printed object.
[0070] The polymer substrate may comprise more than one type of
polymer. The polymer substrate may comprise two or more polymers
present conjointly in various mixtures formed by physical blending,
mixing, dissolution, precipitation, the interconnection of moulded
or 3D printed parts, etc.
[0071] The inventors have found that the methods of the invention
can be used to simultaneously colour different polymers with
different types and classes of colourant.
[0072] The polymer substrate may be a fibre substrate, e.g. a yarn,
a fabric or a garment or part of a garment.
[0073] The fibre substrate may comprise synthetic fibres or natural
fibres or a mixture thereof. The fibre substrate may comprise
fibres selected from: a polyester, a polyamide, a polyurethane, a
polyalkylene, a polyacrylonitrile, wool, silk, natural or
regenerated cellulose, cellulose ester, hair, polyvinyl chloride,
carbon or a mixture thereof.
[0074] Exemplary polyesters include poly(ethylene terephthalate)
(PES), poly(butylene terephthalate) (PBT), poly(trimethylene
terephthalate) (PTT). Exemplary polyurethanes include Lycra.RTM..
Exemplary polyamides include nylon.
[0075] The fibre substrate may be or may comprise polyamide fibres,
e.g. nylon fibres.
[0076] The fibre substrate may comprise polyester fibres or a
mixture of a polyester with a fibre selected from cotton, wool,
silk and polyurethane (e.g. Lycra.RTM.). The fibre substrate may
comprise PES fibres or a mixture of PES with a fibre selected from
cotton, wool, silk and polyurethane (e.g. Lycra.RTM.). The fibre
substrate may be a polyester. The fibre substrate may be PES. The
fibre substrate may comprise a mixture of a polyester with a fibre
selected from cotton, wool, silk and polyurethane (e.g.
Lycra.RTM.). The fibre substrate may comprise a mixture of PES with
a fibre selected from cotton, wool, silk and polyurethane (e.g.
Lycra.RTM.).
[0077] The fibre substrate may comprise silk or wool fibres.
[0078] It may be that the fibre substrate comprises both polyester
fibres and at least one other type of fibre selected from cotton,
regenerated cellulose, wool, silk, polyamide, a different
polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere
and a polyurethane. The fibre substrate may comprise a material
that is a blend of polyester fibres and at least one fibre selected
from other type of fibre selected from cotton, regenerated
cellulose, wool, silk, polyamide, a different polyester,
polyvinylchloride, polyacrylonitrile, mohair, cashmere and a
polyurethane. The fibre substrate may be a material that is a blend
of polyester fibres and at least one fibre selected from cotton,
regenerated cellulose, wool, silk, polyamide, a different
polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere
and a polyurethane. Alternatively, the fibre substrate comprises a
first material that comprises polyester fibres and a second
material that comprises at least one fibre selected from cotton,
regenerated cellulose, wool, silk, polyamide, a different
polyester, polyvinylchloride, polyacrylonitrile, mohair, cashmere
and a polyurethane. The fibre substrate may be a whole garment,
e.g. a trainer or pair of trainers, a shirt or blouse, a dress, a
pair of trousers, a skirt, a t-shirt etc.
[0079] It may be that the fibre substrate comprises both polyester
fibres and at least one other type of fibre selected from cotton,
wool, silk, mohair, cashmere and a polyurethane. The fibre
substrate may comprise a material that is a blend of polyester
fibres and at least one fibre selected from other type of fibre
selected from cotton, wool, silk, mohair, cashmere and a
polyurethane. The fibre substrate may be a material that is a blend
of polyester fibres and at least one fibre selected from cotton,
wool, silk, mohair, cashmere and a polyurethane. Alternatively, the
fibre substrate comprises a first material that comprises polyester
fibres and a second material that comprises at least one fibre
selected from cotton, wool, silk, mohair, cashmere and a
polyurethane.
[0080] As mentioned above, the inventors have found that the
methods of the invention can be used to simultaneously colour
different polymers with different types and classes of colourant.
In particular, the methods of the invention can be used to
simultaneously colour (e.g. dye) different fibres with different
types and classes of colourant (e.g. dye). This offers the
possibility that, with judicious choice of fabric, a blended fabric
could be generated in which a pattern is designed into the weave of
the fabric and the different fibres within the weave can
simultaneously and selectively be dyed different colours. Likewise,
a whole garment that is formed of two or more different materials
(e.g. a shoe, for example a sports shoe or pair of sports shoes)
can be dyed once formed and the various materials can be dyed
different colours simultaneously. This would allow for the bespoke
dyeing, based on the purchaser's selected colour preferences, of a
whole garment either in a distribution warehouse or in a shop.
The Colourant(s)
[0081] The at least one colourant may comprise at least one
pigment.
[0082] The at least one colourant may comprise at least one
dye.
[0083] The at least one colourant may be a single dye. The at least
one colourant may be mixture of two or more dyes.
[0084] Suitable dyes include disperse dyes, solvent dyes, vat dyes,
sulphur dyes, mordant dyes, acid dyes, direct dyes and reactive
dyes. The disperse dyes, solvent dyes, vat dyes, sulphur dyes,
mordant dyes, acid dyes, direct dyes and reactive dyes that can be
used in the methods of the invention include all dyes classified as
such in The Colour Index.TM. published by the Society of Dyers and
Colourists (SDC) and American Association of Textile Chemists and
Colourists (AATCC). In certain embodiments, the disperse dyes,
solvent dyes, vat dyes, sulphur dyes, mordant dyes, acid dyes,
direct dyes and reactive dyes that can be used in the methods of
the invention may include all dyes classified as such in The Colour
Index.TM. on the 1 May 2017.
[0085] The at least one dye may include a disperse dye. The single
dye may be a disperse dye.
[0086] The at least one dye may include an acid dye (e.g. a
non-metallised acid dye or a pre-metallised acid dye). The single
dye may be an acid dye (e.g. a non-metallised acid dye or a
pre-metallised acid dye).
[0087] The at least one dye may include a vat dye. The single dye
may be a vat dye.
[0088] The at least one dye may include a reactive dye. The single
dye may be a reactive dye.
[0089] The at least one dye may include a direct dye. The single
dye may be a direct dye.
[0090] The at least one pigment may include a pigment selected from
an organic pigment, an inorganic pigment and a metallic
pigment.
[0091] Where the polymer (e.g. fibre) substrate to be coloured
comprises different polymers (e.g. different fibres), a mixture of
two or more classes or types of colourant (e.g. dye) may be used.
For example, where a fibre substrate comprises both polyester
fibres (e.g. PES) and a natural fibre (e.g. cotton, silk or wool),
a mixture of a disperse dye (to dye the polyester fibres) and a
reactive dye (to dye the natural fibres) might be used.
Alternatively a mixture of a disperse dye (to dye the polyester)
and a direct dye (to dye the natural fibre) might be used. In a
further alternative, a mixture of a disperse dye (to dye the
polyester fibres) and an acid dye (to dye the natural fibres) might
be used. In a further example, where a fibre substrate comprises
polyester fibres (e.g. PES), cotton fibres and either wool or silk
fibres, a mixture of a disperse dye (to dye the polyester fibres),
a reactive dye (to dye the cotton fibre) and an acid dye (to dye
the wool or silk fibres) might be used.
[0092] The invention may further be described in the following
numbered paragraphs: [0093] 1. A method of dyeing a fibre
substrate, the method comprising: [0094] a) subjecting the fibre
substrate to a dye liquor at a temperature T1, T1 being below
100.degree. C., said dye liquor comprising at least one dye
dissolved in a first solvent system to provide the fibre substrate
wetted with the dye liquor; [0095] b) adding a second solvent
system to the fibre substrate wetted with the dye liquor, without
raising the temperature above a temperature T2, T2 being below
100.degree. C., to provide the dyed fibre substrate wetted with a
mixture of the first solvent system and the second solvent system;
and [0096] c) separating the dyed fibre substrate from the mixture
of the first and second solvent systems and any remaining dye;
wherein the dye or each dye is more soluble in the first solvent
system than in the second solvent system. [0097] 2. A method of
paragraph 1, wherein the step of adding the second solvent system
comprises adding the second solvent system portionwise to the
mixture of the fibre substrate and the dye liquor. [0098] 3. A
method of paragraph 1 or paragraph 2, wherein the second solvent
system comprises water. [0099] 4. A method of paragraph 3, wherein
the second solvent system is water. [0100] 5. A method of any
preceding paragraph, wherein the first solvent system and the
second solvent system are miscible. [0101] 6. A method of any
preceding paragraph, wherein the first solvent system is an organic
solvent or a mixture of one or more organic solvents. [0102] 7. A
method of paragraph 6, wherein the first solvent system is a polar
organic solvent or a mixture of polar organic solvents. [0103] 8. A
method of paragraph 7, wherein the first solvent system is acetone.
[0104] 9. A method of any preceding paragraph, wherein the fibre
substrate comprises fibres selected from: a polyester, nylon, a
polyurethane, wool, silk, cotton or a mixture thereof. [0105] 10. A
method of paragraph 10, wherein the fibre substrate comprises
polyester fibres or a mixture of a polyester with a fibre selected
from cotton, wool, silk and a polyurethane 11. A method of any
preceding paragraph, wherein the ratio of the total volume of the
first solvent system to the total volume of the second solvent
system may be in the range 1:2 to 1:20. [0106] 12. A method of
paragraph 11, wherein the ratio of the total volume of the first
solvent system to the total volume of the second solvent system may
be in the range 30:70 to 10:90. [0107] 13. A method of any
preceding paragraph, wherein the weight ratio of the fibre
substrate to the first solvent system is in the range from 3:1 to
1:3. [0108] 14. A method of any preceding paragraph, wherein the at
least one dye is a disperse dye. [0109] 15. A method of any
preceding paragraph, wherein the method comprises dissolving the at
least one dye in the first solvent system to form the dye liquor
16. A method of any preceding paragraph, wherein the dye liquor
does not comprise a dispersing agent. [0110] 17. A fibre substrate
obtainable according to the method of any preceding paragraph.
BRIEF DESCRIPTION OF THE DRAWINGS
[0111] Embodiments of the invention are further described
hereinafter with reference to the accompanying drawings, in
which:
[0112] FIG. 1 shows the high temperature (HT) PES dyeing method
used as a comparator in the Examples below;
[0113] FIG. 2 shows the reduction clearing process employed for the
Examples;
[0114] FIG. 3 provides a general depiction of controlled
precipitation dyeing method of the invention;
[0115] FIG. 4 shows the colour strength of 2% omf dyeings on PES
achieved using controlled precipitation method of the invention;
Teratop Yellow HL-G 150%; 120 mins at 98.degree. C.;
[0116] FIG. 5 shows the colour strength of 2% omf dyeings on PES
achieved using controlled precipitation method of the invention;
Teratop Yellow HL-G 150%; 30', 60' and 90' at 98.degree. C.;
[0117] FIG. 6 shows the colour strength of 2% omf dyeings on PES
achieved using controlled precipitation method of the invention for
20 mins at 98.degree. C.; Teratop Yellow HL-G 150%;
[0118] FIG. 7 shows the colour strength of 2% omf dyeings on PES
achieved using controlled precipitation method of the invention for
120 mins at 85.degree. C.; Teratop Yellow HL-G 150%;
[0119] FIG. 8 shows the colour strength of 2% omf dyeings on PES
achieved using controlled precipitation method of the invention for
20 mins at 98.degree. C. (Teratop Blue HL-G 150%: left and Teratop
Pink HL-G 150%: right);
[0120] FIG. 9 shows the dyeing method used for the dyeing methods
described in Examples 3, 4 and 5;
[0121] FIG. 10 shows the colour strength of 2% omf dyeing of crude
grade Teratop Yellow HL-G 150% on a fabric composite comprising
polyester fabric attached to scoured PA 66 fabric;
[0122] FIG. 11 shows the colour strength of 2% omf dyeings of
commercial Teratop Yellow HL-G 150% on PES as a function of dyeing
temperature using DMSO as solvent
DETAILED DESCRIPTION
[0123] Organic solvents are organic compounds that are liquids at
room temperature and atmospheric pressure. Typically, organic
solvents are compounds that comprise both carbon atoms and hydrogen
atoms. One exception to this is carbon tetrachloride. Organic
solvents may also comprise oxygen, nitrogen, chlorine, fluorine or
sulphur.
[0124] The term `wetted` is used in this specification to mean that
the polymer (e.g. fibre) substrate is in contact with a liquid,
e.g. the dye liquor or the mixture of the first solvent system and
the second solvent system. It may mean that the substrate (e.g.
fibre substrate) is soaked in the liquid, e.g. saturated with the
liquid. It may mean that the substrate (e.g. fibre substrate) is
coated in the liquid. It may mean that the substrate (e.g. fibre
substrate) is immersed in the liquid. Other techniques that could
be used include spraying, soaking, vapourisation, imbibition,
etc.
[0125] The polymer (e.g. fibre) substrate is described as
`coloured` where the colourant molecules have become absorbed into
the substrate (e.g. into the fibres). Throughout the description
and claims of this specification, the words "comprise" and
"contain" and variations of them mean "including but not limited
to", and they are not intended to (and do not) exclude other
moieties, additives, components, integers or steps. Throughout the
description and claims of this specification, the singular
encompasses the plural unless the context otherwise requires. In
particular, where the indefinite article is used, the specification
is to be understood as contemplating plurality as well as
singularity, unless the context requires otherwise.
[0126] Features, integers, characteristics, compounds, chemical
moieties or groups described in conjunction with a particular
aspect, embodiment or example of the invention are to be understood
to be applicable to any other aspect, embodiment or example
described herein unless incompatible therewith. All of the features
disclosed in this specification (including any accompanying claims,
abstract and drawings), and/or all of the steps of any method or
process so disclosed, may be combined in any combination, except
combinations where at least some of such features and/or steps are
mutually exclusive. The invention is not restricted to the details
of any foregoing embodiments. The invention extends to any novel
one, or any novel combination, of the features disclosed in this
specification (including any accompanying claims, abstract and
drawings), or to any novel one, or any novel combination, of the
steps of any method or process so disclosed.
[0127] The reader's attention is directed to all papers and
documents which are filed concurrently with or previous to this
specification in connection with this application and which are
open to public inspection with this specification, and the contents
of all such papers and documents are incorporated herein by
reference.
EXAMPLES
General Methods
Materials
[0128] Scoured poly(ethylene terephthalate) (PES) fabric (120
gm.sup.-2), scoured, bleached and mercerised woven cotton fabric
(180 gm.sup.-2) and scoured PA 66 fabric (116 gm.sup.-2) was
obtained from Whaleys (Bradford, UK). Commercial grade as well as
crude grade (ie as-synthesised) samples of three disperse dyes,
namely Teratop Yellow HL-G 150%, Teratop Blue HL-G 150% and Teratop
Pink HL-G 150% were kindly provided by Huntsman (Switzerland).
Commercial dyes were used in this work so as to reflect commercial
dyeing practice whilst equivalent crude grade dyes were also used
to determine whether it would be possible to dye PES using
dispersant-free disperse dyes. The three dyes used were chosen
arbitrarily as being representative of modern commercial disperse
dyes. A 2% omf depth of shade was used for each of the three dyes
as this provided typical pale/medium depth dyeings.
[0129] Samples of Polysorbate 20, Polysobate 60, Polysorbate 80,
Lecithin and Superclean were obtained from Sigma-Aldrich. All other
chemicals were of general purpose grade.
[0130] From measured values of the relative dye contents of the
respective pairs of commercial grade and crude grade dye samples,
the amount of crude grade dye employed in dyeing was adjusted so
that the depth of shade obtained (ie 2% omf) was the same as that
secured using the commercial grade dye, was obtained.
Comparative General Method
[0131] The high temperature (HT) dyeing method used for comparison
in this work is shown in FIG. 1.
[0132] The PES fabric (5 g or 10 g) was dyed using both the
commercial grade and grade crude disperse dyes following the
procedure shown in FIG. 1. At the end of dyeing, the dyed sample
was removed from the dyebath, squeezed to remove surplus dye liquor
and rinsed in water according to the procedure depicted in FIG. 1.
The dyed sample was then squeezed once more and subjected to the
reduction clear procedure displayed in FIG. 2. At the end of the
reduction clearing process the sample was removed, squeezed to
remove surplus liquor and rinsed in cold water as shown in FIG. 2.
The reduction cleared dyeing was squeezed and allowed to dry in the
open air.
General Method of the Invention
[0133] The controlled precipitation method of the invention is
illustrated in a general sense in FIG. 3.
Example 1--Development of the Methodology Using Disperse Dyes, PES
and Acetone
[0134] The method depicted in FIG. 3 was carried out with a.sub.1;
a.sub.2; a.sub.3; a.sub.4=10 cm.sup.3 water; t.sub.1=30';
t.sub.2=30'; a.sub.3=30'; a.sub.4=30'; x=98.degree. C.
[0135] The disperse dye was dissolved in a given volume (in this
case 10 cm.sup.3) of acetone and the ensuing solution was applied
to the PES fibre.
[0136] When the temperature of the dyebath reached 98.degree. C., a
volume (10 cm.sup.3) of water was added and dyeing continued for a
certain period of time, after which a further 10 cm.sup.3 of water
was added. This process continued until the final dyebath volume
was 50 cm.sup.3, corresponding to a 1:10 liquor ratio. Thus, over
the length of the dyeing process, the ratio of water:acetone was
gradually increased from 0:100 at the start of dyeing to 80:20 at
the end of dyeing.
[0137] Without wishing to be bound by theory, the purpose of
progressively introducing water to the acetone dye solution was to
gradually force the disperse dye to precipitate out of solution in
a controlled manner, so as to achieve increased dye-fibre
substantivity and, thus, increased dye uptake, in a controlled and
measured manner.
[0138] Following the procedure just described, the total dyeing
time at 98.degree. C. was 120 mins. FIG. 4 reveals that using this
approach, the ensuing dyeing displayed very high colour strength,
which was considerably greater than that secured using the
commercial grade dye and the conventional HT dyeing method at
130.degree. C. Visual inspection revealed that the dye
precipitation method of the invention not only provided a deeper
depth of shade than the HT method but, significantly, the level of
dyebath exhaustion secured was much greater.
[0139] Thus the higher colour strength of the 120 mins 98.degree.
C. dyeing (FIG. 4) can be attributed to the greater extent of dye
exhaustion achieved. The fact that the residual dyebath was
essentially free of unexhausted disperse dye offers obvious cost
and environmental potential. In other words, in order to achieve a
colour strength that is equivalent to that furnished using a
commercial grade dye employing a conventional 2% omf dyeing method
at 130.degree. C. (ie an f.sub.k value of .about.50) will require
less disperse dye, if the controlled precipitation dyeing method of
the invention is used (ie .about.1.25% omf dye), because virtually
100% dye exhaustion is achieved. Furthermore, because crude grade
disperse dye was used for the precipitation dyeing method of the
invention, then the exhausted dyebath will contain essentially no
dye, zero dispersing agent and zero levelling agent, compared to
the residual dyebath that will ensue from the conventional HT
dyeing method.
[0140] Attempts were made to reduce the length of dyeing time at
98.degree. C.; for this, in FIG. 3, a.sub.1, a.sub.2, a.sub.3 and
a.sub.4=10 cm.sup.3 water and the total time at the commercial boil
was 90 min, 60 min and 30 min (in all cases
a.sub.1=a.sub.2=a.sub.3=a.sub.4. As FIG. 5 shows, reducing the
dyeing time at 98.degree. C. did not affect the colour yield of the
ensuing dyeings; a comparison of FIGS. 4 and 5 shows that the
colour yields of all four dyeings were the same.
[0141] When the total time at the commercial boil was further
reduced to 20 mins (ie, a.sub.1, a.sub.2, a.sub.3 and a.sub.4=10
cm.sup.3 water and a.sub.1=a.sub.2=a.sub.3=a.sub.4=5') the colour
strength of the dyed fabric was similar to that achieved for dyeing
times of 30, 60, 90 and 120 mins (FIG. 6). However, with further
reduction of dyeing time at the commercial boil the colour strength
of the dyeings reduced.
[0142] When the temperature of dyeing was lowered from 98.degree.
C. to 85.degree. C., it was found (FIG. 7) that whilst the colour
strength of dyeings carried out for 120 min were the same as those
achieved at 98.degree. C., shorter dyeing times at 85.degree. C. of
60 min and 90 min produced dyeings that were of lower colour
strength. As observed for dyeings undertaken at the commercial
boil, the residual dyebath obtained after 120 min at 85.degree. C.
was observed on visual inspection to be devoid of dye.
[0143] When two other disperse dyes, namely Teratop Blue HL-G 150%
and Teratop Pink HL-G 150%, were applied to PES using the
precipitation dyeing method of the invention for 20 min at
98.degree. C., and the colour strengths of the dyeings were
compared to those secured using the HT dyeing method (ie at
130.degree. C.) are shown in FIG. 8.
[0144] It is apparent that for each of the dyes, higher colour
strength dyeings were achieved using the precipitation dyeing
method of the invention at 98.degree. C. (FIG. 8) and, also, that
the extent of dye exhaustion observed, was much higher for the HT
dyeing method.
Example 2--Fastness
[0145] Table 1 shows that 2% omf dyeings obtained using the three
commercial grade dyes when applied using the HT method (i.e.
130.degree. C.) displayed very good fastness to washing at
60.degree. C., as expected; visual inspection also showed the
impressive depths of shade of the dyeings after wash fastness
testing. The results presented in Table 1 also reveal that the
corresponding dyeings which had been produced using crude grade
samples of the three dyes employing the precipitation dyeing method
of the invention at 98.degree. C. for 20 min displayed essentially
the same high level of wash fastness. The latter findings are
impressive when it is recalled that the colour strength of the
98.degree. C. dyeings were much greater than that of their
130.degree. C. counterparts. Thus, as expected, the manner by which
the disperse dyes were applied (ie differences in dyeing
temperature, dyeing duration and acetone) had no effect on wash
fastness.
TABLE-US-00001 TABLE 1 fastness of 2% omf dyeings on PES produced
using the HT method (commercial grade dyes at 130.degree. C.) and
20 min precipitation method of the invention at 98.degree. C., to
ISO 105-C06/C2S (60.degree. C.) Teratop HL- dyeing change bleached
G 150% grade temp/.degree. C. in shade wool acrylic polyester
polyamide cotton Diacetate Yellow commercial 130 5 5 5 5 4/5 5 4.5
crude 98 5 5 5 5 4.5 5 4.5 Blue commercial 130 4/5 4/5 5 4 5 5 4/5
crude 98 4/5 4/5 5 4 4/5 5 4/5 Pink commercial 130 5 4 5 4 4/5 5
4/5 crude 98 5 4 5 4 4/5 5 4/5
[0146] When the above method was followed but using polyester
fabric which had been previously wetted-out using water and
squeezed to remove surplus water, the colour strength of the
ensuing dyeing obtained for 20 min at 98.degree. C. was comparable
to that achieved using dry polyester fabric.
Example 3--Other Fabrics and Other Classes of Dyes
[0147] The methods of the invention can also be used to dye other
substrates using other dye types. The following example describes
the dyeing of wool, silk and polyamide substrates with acid dyes
and a disperse dye.
[0148] The general method used throughout this example is shown in
FIG. 9. A Roaches Pyrotec S dyeing machine) was used. 0.1 g of
commercial dye was dissolved in 10 cm.sup.3 acetone and the ensuing
solution was placed in a 300 cm.sup.3 capacity dye tube, followed
by 5 g of fabric. The sealed dye tube was heated to 85.degree. C.
and then 10 cm.sup.3 of water was injected into the dyeing tube. A
further total of 40 cm.sup.3 of water was injected at time
intervals, as shown in FIG. 9. The total dyeing time at 85.degree.
C. was 20 min.
[0149] Both non-metallised acid (Erionyl Red A-28F (Huntsman)) and
1:2 pre-metallised acid dyes (Supralan Yellow 4GL (Dystar); Lanaset
Yellow 2R (Huntsman) and Neutrilan Yellow A-3R (Yorkshire)) were
applied to wool, silk and PA fabrics using the dyeing methods of
the invention. In addition, both commercial grade as well as crude
grade samples of the disperse dye Teratop Yellow HL-G 150%
(Huntsman) was applied to wool, PA and wool fibres.
[0150] Both silk and wool were successfully dyed at 85.degree. C.
in 20 min using the non-metallised dye Erionyl Red A-28F. colour
measurement L*=34.3 a*=63.4 b*=58.1
[0151] In comparison to the conventional method for dyeing wool
with such dye types, which is normally carried out at higher
temperature (for wool: 98.degree. C.) under acidic conditions for
60-90 min, the novel dyeing method is advantageous insofar as it
enables the fibres to be dyed at a lower temperature of 85.degree.
C. (for wool) in a short time (ie 20 min) without recourse to pH
adjustment, thereby offering savings in time, energy and
chemicals.
[0152] Both silk and wool were successfully dyed at 85.degree. C.
for 20 min using the 1:2 metal complex dye Supralan Yellow 4GL at
85.degree. C. for 20 min using the novel dyeing method colour
measurement L*=83.8 a*=6.9 b*=116.5. Once again, compared to the
conventional method for dyeing wool with such dye types, which is
normally carried out at higher temperature (for wool: 98.degree.
C.) under acidic conditions for 60-90 min, the novel dyeing enables
the fibres to be dyed at 85.degree. C. in a short time (ie 20 min)
and without using pH adjustment, thereby offering savings in time,
energy and chemicals.
[0153] The novel dyeing method also enabled wool and silk to be
dyed at 85.degree. C. for 20 min using the 1:2 metal complex dyes
Neutrilan Yellow A-3R colour measurement L*=48.7 a*=34.5 b*=8.1 and
Lanaset Yellow 2R. Once again, compared to the conventional method
for dyeing wool with such dye types, which is normally carried out
at higher temperature (for wool) under acidic conditions for 60-90
min, the novel dyeing enables the fibres to be dyed at 85.degree.
C. in a short time (ie 20 min), thereby offering savings in time,
energy and chemicals.
[0154] Both commercial (i.e. containing dispersants) and crude
(i.e. not containing dispersants) samples of the disperse dye
Teratop Yellow HL-G 150% were successfully applied to both scoured
wool and silk and PA fibres using the novel dyeing method at
85.degree. C. and 20 min.
Example 4--Blends of Fibres
[0155] The methods of the invention can also be used to dye a
combination of different types of fibre. The following example
describes the dyeing of polyester/cotton blends as well as
polyester/Nylon blends using disperse dye.
[0156] The general method used throughout this example is shown in
FIG. 9. A Roaches Pyrotec S dyeing machine) was used. The
appropriate amount of crude grade disperse dye to provide a 2% omf
shade was dissolved in 10 cm.sup.3 acetone and the ensuing solution
was placed in a 300 cm.sup.3 capacity dye tube, followed by a
fabric composite comprising 2.5 g of polyester fabric attached to
2.5 g of scoured, bleached and mercerised woven cotton fabric. The
sealed dye tube was heated to 98.degree. C. and then 10 cm.sup.3 of
water was injected into the dyeing tube. A further total of 40
cm.sup.3 of water was injected at time intervals, as shown in FIG.
9. The total dyeing time at 85.degree. C. was 20 min.
[0157] 2% omf dyeings of the crude (i.e. not containing
dispersants) disperse dyes Teratop Yellow HL-G 150%, Teratop Blue
HL-G 150% and Teratop Pink HL-G 150%, were successfully achieved
using the novel dyeing method at 98.degree. C. and 20 min. Whilst
the polyester component was fully dyed, the cotton fabric was
uncoloured. This was anticipated based on the relative
hydrophobicity of the cotton and polyester fibres and the
corresponding different substantivity for the fibres displayed by
the disperse dye.
[0158] Following the method described above, a 2% omf dyeing using
the crude grade disperse dye Teratop Yellow HL-G 150% was obtained
using a fabric composite comprising 2.5 g of polyester fabric
attached to 2.5 g of scoured PA 66 fabric.
[0159] Both the polyester and nylon 66 fabrics were dyed, as shown
by FIG. 10, but the polyester was of higher depth of shade, as
expected, owing to the greater hydrophobicity of the polyester
material and the corresponding greater substantivity displayed by
the dye towards the polyester fibre.
Example 5--Solvent Mixtures
[0160] The first solvent can comprise a mixture of two or more
organic solvents or a mixture of water and an organic solvent.
[0161] The general method used throughout this example is shown in
FIG. 9, with the acetone replaced with mixed solvent systems as
described below. A Roaches Pyrotec S dyeing machine) was used.
Crude grade disperse dye Teratop Yellow HL-G 150%, was dissolved in
a mixture of 10 cm.sup.3 acetone and 2 cm.sup.3 of water. The
ensuing solution was placed in a 300 cm.sup.3 capacity dye tube,
followed by polyester fabric. The sealed dye tube was heated to
98.degree. C. and then 10 cm.sup.3 of water was injected into the
dyeing tube. A further total of 40 cm.sup.3 of water was injected
at time intervals. The total dyeing time at 98.degree. C. was 20
min.
[0162] The colour strength of the ensuing dyeing was very similar
to that obtained when acetone only had been used as the first
solvent.
[0163] When the above method was used but crude grade disperse dye
Teratop Yellow HL-G 150% was dissolved in a mixture of 4 cm.sup.3
acetone and 6 cm.sup.3 of ethanol, successful dyeing was
achieved.
Example 6--Other Solvents
[0164] Although acetone is an excellent solvent for crude grade
disperse dyes, other, higher boiling solvents were examined. Being
higher boiling, these solvents offer a reduced fire risk compared
to acetone.
[0165] Different amounts (5, 10 and 20 cm.sup.3) of DMSO were used
to dissolve 2% omf commercial Teratop Yellow HL-G and different
amounts of water (45, 40 and 30 cm.sup.3) were added portionwise so
as to achieve a 1:10 LR overall were used. The colour strength of
the dyed polyester is shown in FIG. 11
[0166] From FIG. 11 it is apparent that lower values of colour
strength are obtained in comparison to that of PES which had been
dyed using acetone, which can be attributed to the lower solubility
of the dye in DMSO. However, as FIG. 11 shows, by increasing the
amount of DMSO employed, higher colour strength dyeings were
achieved. While these dyeings did not exhibit the high colour
strengths of the acetone processes, they still offer benefits in
terms of lower temperature of process with lower energy use and the
ability to dye PES concurrently with non-PES fibres.
[0167] Various other high boiling point solvents were used to dye
PES at a 2% omf depth of shade of crude Teratop Yellow HL-G, namely
ethylene glycol diacetate (EGD), triethylene glycol monomethyl
ether (TGM), dipropylene glycol methyl ether (DME) and
1-methoxy-2-propanol.
[0168] Samples of PES fabric were dyed at 95.degree. C. using the
controlled precipitation dyeing method shown in FIG. 3, employing
each of the above solvents (10 cm.sup.3) and 4 additions of water
(40 cm.sup.3 water in total; 1:10 LR in total), the total dyeing
time at 95.degree. C. being 20 mins.
[0169] Colour measurement data (illuminant D.sub.65; specular
included; UV excluded; 10.degree. standard observer)
triethylene glycol monomethyl ether (TGM) L*=88.9a*=30.5b*=95.3
ethylene glycol diacetate (EGD) L*=86.1a*=19.1b*=80.1
[0170] Each of the four solvents were able to dissolve the crude
disperse dye and can be utilised in the precipitation dyeing
method.
Example 7--Vat Dyes
[0171] To investigate whether the novel precipitation dyeing method
could be used to apply to vat dyes, indigo was selected. Samples of
PES fabric were dyed at 95.degree. C. using the controlled
precipitation dyeing method shown in FIG. 3, employing acetone as
solvent (10 cm.sup.3) and 4 additions of water (40 cm.sup.3 water
in total; 1:10 LR in total), the total dyeing time at 95.degree. C.
being 20 mins.
[0172] It was found that the vat dye could be applied from acetone
using the precipitation dyeing method.
[0173] No reductants or pH adjustments were needed to achieve this
result.
[0174] Colour measurement data (illuminant D.sub.65; specular
included; UV excluded; 10.degree. standard observer)
[0175] L*=55.9 a*=-6.3 b*=-10.9
Example 8--One Pot Dyeing of Mixtures of Fibres with Mixtures of
Classes of Dyes
[0176] The novel precipitation dyeing method may offer the
potential for dyeing fibre blends using different classes/types of
dye simultaneously, in the same dyebath, in the absence/much
reduced amounts of dyebath auxiliaries.
[0177] For this example, samples (2.5 g) of fabric were dyed at
different temperatures using the controlled precipitation dyeing
method shown in FIG. 3, employing acetone as primary solvent and
using additions of water or solutions of inorganic electrolyte or
alkali, as well as electrolyte/alkali, the total dyeing time being
20 mins. The amounts are given in the examples below
PES/Cotton Using Reactive Dye and Disperse Dye
[0178] Duractive Black B (C.I. Reactive Black 5) and crude Teratop
Yellow HL-G were dissolved in acetone. Separate samples of PES
fabric and cotton fabric were dyed together at 95.degree. C. using
the controlled precipitation dyeing method shown in FIG. 3,
employing 4 additions of either a) water or b) a solution
comprising 15 gl.sup.-1 Na.sub.2CO.sub.3 and 50 gl.sup.-1 NaCl
(1:10 LR in total), the total dyeing time being 20 mins.
[0179] It was found that it is possible to dye both the hydrophobic
PES and hydrophilic cotton substrates in the same dyebath in 20
minutes at 95.degree. C., using a mixture of non-ionic disperse dye
and anionic reactive dye. As expected the colour yield secured
using both electrolyte and alkali favoured reactive dye uptake.
[0180] Since it is now known that reactive dye exhaustion on cotton
in the absence of added inorganic electrolyte can be increased
through the use of low liquor ratio, dyeings were also made using
two 10 cm.sup.3 additions (1:6 LR) of a solution comprising 15
gl.sup.-1 Na.sub.2CO.sub.3; an improvement in depth of shade of the
reactive dye on the cotton component was achieved compared to that
obtained at a 1:10 LR.
[0181] To samples of PES fabric and cotton fabric Commercial
Novacron Red FN-2BL was applied in conjunction with crude Teratop
Yellow HL-G dissolved in acetone. Four 10 cm.sup.3 additions of a
solution comprising 15 gl.sup.-1 Na.sub.2CO were made (1:10 LR);
the total dyeing time was 20 mins at 95.degree. C. It was found
that the precipitation method enables PES and cotton substrates to
be dyed in the same dyebath in 20 minutes at 95.degree. C., using a
mixture of disperse dye and reactive dye.
Colour Measurement
[0182] PES L*=75.8 a*=18.9 b*=116.5
[0183] cotton L*=52.9 a*=4.3 b*=-19.8
PES/Cotton Using Direct Dye and Disperse Dye
[0184] C.I. Direct Red 81 and crude Teratop Yellow HL-G were
dissolved in acetone. Samples of PES fabric and cotton fabric were
dyed at 95.degree. C. using the controlled precipitation dyeing
method shown in FIG. 3, employing 4 additions of water or a
solution containing 20 gl.sup.-1 NaCl (1:10 LR in total), the total
dyeing time being 20 mins.
Colour Measurement
[0185] PES L*=73.1 a*=16.1 b*=117.6
[0186] cotton L*=41.1 a*=66.9 b*=19.4
[0187] Dyeings were also made using two 10 cm.sup.3 additions (1:6
LR) of water
[0188] Colour Measurement
[0189] PES L*=78.4 a*=35.8 b*=111.9
[0190] cotton L*=52.3 a*=61.6 b*=11.2
[0191] It was found that both PES and cotton fibres can be dyed
simultaneously in the same dyebath in 20 minutes at 95.degree. C.,
using a mixture of disperse dye and direct dye; as expected the
colour yield secured using electrolyte favoured dye uptake, and
using a lower liquor ratio (ie 1:6) improved direct dye adsorption
in the absence of added inorganic electrolyte.
PES/Wool Using Non-Metallised and Pre-Metallised Acid Dyes in
Conjunction with Disperse Dye
[0192] Commercial samples of either a) the non-metallised acid dye
Erionyl Red A-28F or b) the 1:2 pre-metallised acid dye Neutrilan
Yellow A-3R were dissolved in acetone along with crude (i.e.
containing no auxiliaries) Teratop Yellow HL-G. Samples of PES
fabric and wool fabric were dyed at 85.degree. C. using the
controlled precipitation dyeing method shown in FIG. 3, employing 4
additions of water (1:10 LR in total), the total dyeing time being
20 mins.
[0193] It was found that PES and wool fibres can be dyed
simultaneously in the same dyebath in 20 minutes at 85.degree. C.,
using a mixture of disperse dye and either non-metallised acid or
pre-metallised acid dyes in the absence of all dyeing auxiliaries.
The wool fabric component was dyed either a red colour or yellow
colour depending on the type of acid dyes used, and the polyester
fabric component was dyed a yellow colour
PES/Silk Using Non-Metallised and Pre-Metallised Acid Dyes in
Conjunction with Disperse Dye
[0194] Commercial samples of either a) the non-metallised acid dye
Erionyl Red A-28F or b) the 1:2 pre-metallised acid dye Neutrilan
Yellow A-3R were dissolved in acetone along with crude (i.e.
containing no auxiliaries) Teratop Yellow HL-G. Samples of PES
fabric and silk fabric were dyed at 85.degree. C. using the
controlled precipitation dyeing method shown in FIG. 3, employing 4
additions of water (1:10 LR in total), the total dyeing time being
20 mins.
[0195] It was found that PES and wool fibres can be dyed
simultaneously in the same dyebath in 20 minutes at 85.degree. C.,
using a mixture of disperse dye and either non-metallised acid or
pre-metallised acid dyes in the absence of all dyeing auxiliaries.
The silk fabric component was dyed either a red colour or yellow
colour depending on the type of acid dyes used, and the polyester
fabric component was dyed a yellow colour
PES/Cotton/Wool Using Non-Metallised Acid and Reactive Dyes in
Conjunction with Disperse Dye
[0196] Commercial samples of the non-metallised acid dye Erionyl
Red A-2BF and Duractive Black B were dissolved in acetone along
with with crude Teratop Yellow HL-G. Samples of PES fabric, wool
fabric and cotton fabric were dyed at 85.degree. C. using the
controlled precipitation dyeing method shown in FIG. 3, employing 4
additions of water (1:10 LR in total), the total dyeing time being
20 mins.
[0197] The cotton fabric component was dyed a blue colour, the wool
fabric was dyed a red colour and the polyester fabric component was
dyed a yellow colour.
[0198] The results showed that PES, wool and cotton fibres can be
dyed different colours simultaneously in the same dyebath in 20
minutes at 85.degree. C., using a mixture of disperse dye, reactive
dye and non-metallised acid dye in the absence of all dyeing
auxiliaries.
Example 8--One Pot Dyeing of a Solid Object
[0199] This example describes the results obtained from dyeing 3D
printed nylon 12 (PA12) with a disperse dye (Dianix Blue-ACE) at
the boil (98.degree. C.) under atmospheric pressure, using two
different solvent systems. The dyed samples obtained were compared
in terms of depth of shade and the process conditions employed
(i.e. temperature, solvent system employed).
[0200] The substrate dyed were white solid, 3D printed nylon 12
parts.
[0201] The dye used in this trial was of commercial grade and was
used as supplied without purification; Dianix Blue ACE manufactured
by Dystar.
[0202] Photographs of all samples were recorded in a light cabinet
under D.sub.65 illuminant, using a Samsung Galaxy S6+ mobile phone
camera.
[0203] All dyeing was carried-out by placing the dye, substrate and
solvent in a container placed on a hot plate and heated to the
required processing temperature. The temperature of the dyebath was
measured using a mercury-in-glass thermometer.
Solvent System 1 (Water)
[0204] A 2% omf (Dianix Blue-ACE) dyeing was produced following the
procedure shown in FIG. 12A, employing a 10:1 LR. At the end of
dyeing, the sample was rinsed thoroughly under running tap water
and dried in the open air. A photograph of the dyed sample is shown
in FIG. 12B
Solvent System 2 (Water:Glycerol; 80:20)
[0205] A 2% omf (Dianix Blue-ACE) was produced following the
procedure shown in FIG. 12C, employing a 10:1 LR (liquor comprising
of water:glycerol; 80:20) At the end of dyeing, the samples was
rinsed thoroughly under running tap water and dried in the open
air. A photograph of the dyed sample is shown in FIG. 12D
[0206] Upon visual inspection of the dyed samples it was apparent
that, the sample obtained using the glycerol: water solvent system
had the highest depth of shade (compare FIG. 12B and FIG. 12D).
* * * * *