U.S. patent application number 15/400832 was filed with the patent office on 2017-04-27 for washing machine comprising a bleaching device and a reservoir for water-insoluble solid particles.
This patent application is currently assigned to Henkel AG & Co. KGaA. The applicant listed for this patent is Henkel AG & Co. KGaA. Invention is credited to Thorsten Bastigkeit, Nicole Bode, Arnd Kessler, Thomas Mueller-Kirschbaum, Christian Nitsch, Peter Schmiedel, Iwona Spill.
Application Number | 20170114488 15/400832 |
Document ID | / |
Family ID | 53525194 |
Filed Date | 2017-04-27 |
United States Patent
Application |
20170114488 |
Kind Code |
A1 |
Spill; Iwona ; et
al. |
April 27, 2017 |
WASHING MACHINE COMPRISING A BLEACHING DEVICE AND A RESERVOIR FOR
WATER-INSOLUBLE SOLID PARTICLES
Abstract
The present invention relates to a washing machine comprising a
washing chamber for receiving a wash liquor and textile substrates
to be cleaned, and a decoloration device (3) which has an inlet (4)
for introducing wash liquor from the washing chamber into the
decoloration device (3) as well as an outlet (5) for discharging
wash liquor from the decoloration device (3) into the washing
chamber, and which, moreover, has at least one electrochemical
activator that is suitable for initiating, within the decoloration
device (3), a process for forming free radicals in the wash liquor.
According to the present invention, the washing machine includes a
reservoir containing water-insoluble solid particles. Furthermore,
a method for washing textile substrates in such a washing machine
is also disclosed.
Inventors: |
Spill; Iwona; (Berlin,
DE) ; Schmiedel; Peter; (Duesseldorf, DE) ;
Bode; Nicole; (Duesseldorf, DE) ; Nitsch;
Christian; (Duesseldorf, DE) ; Kessler; Arnd;
(Monheim am Rhein, DE) ; Bastigkeit; Thorsten;
(Wuppertal, DE) ; Mueller-Kirschbaum; Thomas;
(Solingen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Henkel AG & Co. KGaA |
Duesseldorf |
|
DE |
|
|
Assignee: |
Henkel AG & Co. KGaA
Duesseldorf
DE
|
Family ID: |
53525194 |
Appl. No.: |
15/400832 |
Filed: |
January 6, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2015/065623 |
Jul 8, 2015 |
|
|
|
15400832 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06F 39/083 20130101;
D06F 35/003 20130101; D06F 39/02 20130101; D06F 39/085 20130101;
D06F 35/006 20130101; D06F 34/22 20200201; D06F 35/00 20130101 |
International
Class: |
D06F 35/00 20060101
D06F035/00; D06F 39/00 20060101 D06F039/00; D06F 39/08 20060101
D06F039/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2014 |
DE |
10 2014 213 312.2 |
Claims
1. A washing machine comprising a washing chamber for receiving a
wash liquor and textile substrates to be cleaned, a reservoir for a
large number of water-insoluble solid particles, and a decoloration
device which comprises an inlet for introducing wash liquor from
the washing chamber into the decoloration device as well as an
outlet for discharging wash liquor from the decoloration device
into the washing chamber, and which further comprises at least one
electrochemical activator that is suitable for initiating, within
the decoloration device, a process for forming free radicals in the
wash liquor.
2. The washing machine according to claim 1, wherein the activator
comprises an electrode arrangement including an anode, preferably a
boron-doped diamond electrode, and a cathode.
3. The washing machine according to claim 1, wherein the
decoloration device further comprises a UV radiation source.
4. The washing machine according to claim 1, wherein further
comprising at least one pump, said pump capable of pumping the wash
liquor out from the washing chamber into the decoloration device
and/or out therefrom.
5. The washing machine according to claim 1, further comprising a
control unit for regulating the use and/or the intensity and/or the
duration of the process for forming free radicals.
6. The washing machine according to claim 5, wherein the control
unit has a temperature sensor for detecting the temperature of the
wash liquor.
7. The washing machine according to claim 1, wherein the
decoloration device is located in one or more housings inside or
outside the washing machine.
8. A method for washing textile substrates by using the washing
machine according to claim 1, comprising the steps of: a) filling
the washing chamber of the washing machine with the textile
substrates to be washed; b) starting a wash cycle; c) washing the
laundry by bringing the textile substrates into contact with water,
a detergent, and a large number of water-insoluble solid particles;
d) introducing wash liquor from the washing chamber into the
decoloration device; e) treating the wash liquor in the
decoloration device by using the electrochemical activator; and f)
discharging the treated wash liquor from the decoloration device
into the washing chamber, wherein the introducing and/or
discharging of the wash liquor and the treatment of the wash liquor
in the decoloration device may be performed continuously,
discontinuously, or sequentially.
9. The method according to claim 8, wherein the wash liquor is
adjusted to a temperature of 10.degree. C. to 100.degree. C.
10. The method according to claim 8, wherein the weight ratio of
textile substrate to water-insoluble solid particles is in the
range of 1:1 to 1:30.
11. The method according to claim 8, wherein the water-insoluble
particles a. are inorganic in nature, comprising zeolites, clays,
and/or ceramic; and/or b. are organic in nature, comprising polymer
particles.
12. The method according to claim 11, wherein the water-insoluble
polymer particles comprise polyesters, polyurethanes, and/or
polyamides, including copolymers thereof.
13. The method according to claim 8, wherein the water-insoluble
particles are present in the form of balls, cubes, and/or
cylinders.
14. The method according to claim 8, wherein the particles each
have a mean weight in the range of 20 to 50 mg.
15. The method according to claim 8, wherein the large number of
soiled water-insoluble solid particles are generated with the use
of the electrochemical activator, by being introduced to and
discharged from the decoloration device.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to a washing machine
having a decoloration device, as well as a method for washing
textile substrates in said washing machine.
BACKGROUND OF THE INVENTION
[0002] It is known that colorful textiles (textile substrates) can
lose their color in the washing process. Depending on the wash
temperature, the selected wash program, and the detergent used,
there may be varying degrees of the intensity with which one or
more dyes are washed out from the textile substrates. The dissolved
dyes pass into the wash liquor--generally, washing suds--and are
thereby brought into contact with other textile substrates, into
which the dyes may pass. This leads to undesired discoloration,
especially with bright-colored textile substrates, and may--as an
example of the worst scenario--completely ruin an article of
clothing.
[0003] Today, a large number of different dyes are used in the
textile industry. These dyes vary greatly in the chemical structure
thereof, properties thereof, and binding thereof to a textile.
Thus, for example, distinctions may be made between direct dyes,
reactive dyes, dispersion dyes, acid dyes, vat dyes, and
others.
[0004] Different fabric types--such as cotton, polyamide, or
polyester--require different dye types, in order to have efficient
and long-lasting coloring of these fabrics. This wide range of dyes
used in the textile industry represents a major challenge for
finding efficient measures against discoloration.
[0005] Various efforts have already been made, especially in the
area of detergent compositions, to prevent the color loss process.
Thus, today, color detergents are usually offset with dye transfer
inhibitors, which are intended to prevent the transfer of dyes to
other textile substrates. These additives have a disadvantage in
mostly only being effective one or a small number of dyes, but not
against a broader spectrum of dyes. Commercial dye transfer
inhibitors thus exhibit, for example, a favorable effect against
red direct dye, but no effect or only very little effect against
dispersion dyes, acid dyes, or vat dyes. Precisely such a broad
spectrum of colors does exist, however, in household color loads in
the washing machine, because--for efficiency reasons--colors are
generally only sorted in the broadest sense (darks and lights), but
typically not by individual shades. Achieving an appropriate
effectiveness against such a mixture of colors would require
incorporating a large number of different dye transfer inhibitors
into the detergent compositions. This, however, would have the
undesired effects of raising both the complexity of the detergent
formulation and the costs for the detergent.
[0006] U.S. Pat. No. 3,927,967 A discloses a method for removing
stains from textile substrates, with which the textile substrates
are subjected to a treatment with a detergent solution, a
photoactivator, and oxygen, and are irradiated with visible light
during this treatment process. However, such a method could not be
used to treated dyed textile substrates, in particular, to
eliminate the color loss process, because the treatment would
tackle not only dyes dissolved into the wash liquor but also the
dyes that are bonded to the textile substrates, thereby bleaching
the textile substrates in an undesirable manner and causing the
textile substrates to lose color.
[0007] WO 2009/067838 A2 discloses a method for cleaning the
laundry with electrolyzed water, by means of oxidative radicals.
For this purpose, a water tank is provided, in addition to the
washing machine. The water contained in the tank is electrolyzed by
an electrolysis unit, and thereby enriched with oxidative radicals
that are highly reactive and thus have, inter alia, a cleaning and
disinfecting action. The water treated in this manner is then
supplied to the actual washing process. It is disadvantageous here
that the textile substrates to be washed come into contact with the
electrolyzed water during the wash process. This causes not only
stains in the textile substrates but also the dyes that are bonded
to the textile substrates to be attacked, which may lead to an
undesired fading of the colors.
[0008] WO 01/71083 A discloses a washing machine that has a drum
for receiving articles to be washed, wherein the drum has at least
two rotatable drum sections and a drive, the drum comprising a
plurality of different drum modes, including one mode in which the
rotatable drum parts are driven so as to cause a relative rotation
therebetween. A controller controls the device in order to perform
a plurality of different wash programs, wherein each wash program
has a corresponding drum mode.
[0009] WO 2010/094959 A1 relates to cleaning substrates by using a
solvent-free cleaning system that requires the use of only small
amounts of water. In particular, the document concerns cleaning
textile fibers with the aid of such a system, and provides a device
for use in relation thereto.
[0010] WO 2007/128962 A makes it possible to efficiently separate
the substrate from polymer particles after completion of the
cleaning process, and describes a design for use of two internal
drums.
[0011] The present invention therefore addresses the problem of
providing simple and low-cost measures that minimize the risk of
discoloration during the wash cycle in a washing machine, while
simultaneously protecting the textile substrates to be washed in
the presence of water-insoluble solid particles.
[0012] Furthermore, other desirable features and characteristics of
the present invention will become apparent from the subsequent
detailed description of the invention and the appended claims,
taken in conjunction with the accompanying drawings and this
background of the invention.
BRIEF SUMMARY OF THE INVENTION
[0013] A washing machine comprising a washing chamber for receiving
a wash liquor and textile substrates to be cleaned, a reservoir for
a large number of water-insoluble solid particles, and a
decoloration device (3) which has an inlet (4) for introducing wash
liquor from the washing chamber into the decoloration device (3) as
well as an outlet (5) for discharging wash liquor from the
decoloration device (3) into the washing chamber, and which
moreover has at least one electrochemical activator that is
suitable for initiating, within the decoloration device (3), a
process for forming free radicals in the wash liquor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will hereinafter be described in
conjunction with the following drawing figures, wherein like
numerals denote like elements, and
[0015] FIG. 1 illustrates an embodiment of a decoloration device
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The following detailed description of the invention is
merely exemplary in nature and is not intended to limit the
invention or the application and uses of the invention.
Furthermore, there is no intention to be bound by any theory
presented in the preceding background of the invention or the
following detailed description of the invention.
[0017] The aforementioned problem is solved in a first embodiment
by a washing machine comprising a washing chamber for receiving a
wash liquor and textile substrates to be cleaned, a reservoir for a
large number of water-insoluble solid particles, and a decoloration
device (3) which has an inlet (4) for introducing wash liquor from
the washing chamber into the decoloration device (3) as well as an
outlet (5) for discharging wash liquor from the decoloration device
(3) into the washing chamber, and which moreover has at least one
electrochemical activator that is suitable for initiating, within
the decoloration device (3), a process for forming free radicals in
the wash liquor.
[0018] The washing machine in the sense of the present invention
may fundamentally entail a conventional washing machine, for
example, a cuboid washing machine having a capacity of about 1 to
20 kg, in particular, 4 to 9 kg of laundry, but may also entail an
industrial-use washing machine having any capacity. The invention
thus encompasses washing machine types of different designs and
significantly larger capacities. The washing chamber entails the
space through which wash liquor flows during a wash cycle. In a
household washing machine, this is generally a washing drum and the
immediately surrounding space.
[0019] It has been shown that the dyes passed into the wash liquor
during the wash cycle can be decomposed by free radicals. Free
radicals have at least one unpaired electron and are therefore
extremely reactive, and thus usually short-lived (generally <1
second). They are able to react with the dyes dissolved in the wash
liquor and decompose them. One example is the decomposition of the
dye Acid Orange 7, which is broken down by the interaction with
free radicals into colorless aromatic by-products that are then, in
turn, converted by oxidation into aliphatic acids.
[0020] The washing machine according to the present invention makes
use of this interaction behavior between free radicals and dyes.
For this purpose, the washing machine comprises the decoloration
device, into which the wash liquor enriched with dissolved dyes can
be introduced from the washing chamber. The activator, which is
suitable for initiating a process for forming free radicals in the
wash liquor within the decoloration device, is arranged in the
decoloration device. The free radicals thus formed attack and break
down the dyes in the wash liquor. The wash liquor, having been
treated in this manner, is then guided out from the decoloration
device and into the washing chamber, and supplied to the further
washing process in the washing machine. The proportion of dissolved
dyes in the whole of the wash liquor located in the washing chamber
is thereby significantly reduced, whereby the risk of textile
discoloration is minimized.
[0021] The excellent effect of the free radicals against a variety
of dyes has proven especially advantageous. This makes it possible
to largely forgo detergent additives that are effective only
against individual dyes, and possible to omit stringent sorting of
the textile substrates to be washed according to the different
shades prior to the wash.
[0022] The washing machine according to the present invention is
advantageous in that potentially exclusively the treatment of the
wash liquor and/or also of the water-insoluble solid particles may
take place within the decoloration device; an undesired effect of
the reactive free radicals on the textile substrates located in the
washing chamber--in general, in a washing drum--and the dyed bonded
therein is not possible or is largely eliminated. Both the inlet
for introducing the wash liquor from the washing chamber into the
decoloration device and the outlet for discharging the wash liquor
into the washing chamber are designed for the purpose of making it
impossible for textile substrates and optionally water-insoluble
solid particles to reach the decoloration device. To accomplish
this, the inlet and/or the outlet of the decoloration device may be
fitted, for example, with suitable filters or grates that do not
allow textile substrates to pass through but do allow the wash
liquor and optionally the water-insoluble solid particles to pass
through. The dimensions--in particular, the cross-sectional
area--of the inlet and/or of the outlet may also be sized so as to
render it impossible for textile substrates to enter into the
decoloration device. On the other hand, the inlet and outlet may
also be designed so that the water-insoluble solid particles are
introduced in a targeted manner into the decoloration device.
According to the present invention, control of the inlet and outlet
devices may also be provided, in order to control same in a
time-dependent manner and thus bring in or out only the
respectively desired components.
[0023] The length of the inlet and, in particular, the outlet of
the decoloration unit is then sized such that, taking into account
the mean flow rate of the wash liquor through the decoloration
device and the mean lifespan of the free radicals, it can be
assumed that practically no free radicals are present any longer in
the treated wash liquor upon exiting from the decoloration
device.
[0024] The wash liquor generally entails a wash liquor in which a
detergent is dissolved in water. Depending on the requirements,
other components may be mixed into this wash liquor. In certain
cases, pure water or other suitable liquids may also be put to use.
Components of commercially available detergents are well known to a
person skilled in the art.
[0025] In a preferred embodiment of the present invention, the
electrochemical activator has an electrode arrangement comprising
an anode and a cathode. It is assumed that the chemical processes
take place as follows: in this case, the free radicals in the wash
liquor are formed through an electrochemical process. For this
purpose, the anode and the cathode may be introduced into the
decoloration device and connected to the positive and negative
poles, respectively, of a direct current voltage source. The
working hypothesis is that in the electrochemical process that then
occurs, the water contained in the wash liquor is cleaved to form
OH radicals. The hydroxyl radicals formed in this manner are
capable of oxidizing and thereby rendering non-detrimental the dyes
dissolved in the wash liquor.
[0026] The material of the electrodes may be composed of a variety
of materials, which have, in particular, a high oxygen overvoltage.
For example, the material may be composed of graphite, steel, or
precious metals such as platinum, or also from metal oxides or
mixed oxides. A diamond electrode--in particular, a boron-doped
one--is especially preferably used as the anode. This generally
entails a base body made of plastic, metal, or a semiconductor, for
example, silicon, covered with a thin, polycrystalline diamond
layer. In order to achieve sufficient conductivity for the
electrochemical process, the diamond layer is preferably doped with
boron during production.
[0027] The effect surface area of the anode is preferably between 1
and 500 cm.sup.2, particularly preferably between 2 and 100
cm.sup.2. The electrochemical process is performed at current
intensities in the range of 0.01 to 30 A, preferably 0.1 to 10 A.
In a preferred embodiment of the present invention, the
decoloration device comprises a further activator, in particular, a
UV radiation source, i.e., the process for forming free radicals in
the decoloration device is also initiated by UV irradiation. In
this embodiment variant, the wash liquor used is one that
optionally contains chemical additive components such as hydrogen
peroxide (H.sub.2O.sub.2) or titanium dioxide (TiO.sub.2). The UV
radiation emitted in the decoloration device by the radiation
source activates the hydrogen peroxide or titanium dioxide
optionally contained in the wash liquor, producing--as short-lived
products of this reaction--highly reactive hydroxyl radicals (OH
radicals) that are capable of breaking down the dyes in the wash
liquor. In addition to the aforementioned hydrogen peroxide and
titanium dioxide, it shall be readily understood that a large
number of other chemical additives that can be activated by
irradiation with UV under formation of free radicals are also
suitable. The use of hydrogen peroxide is especially helpful,
because hydrogen peroxide is already present as a bleaching agent
in a large number of detergent compositions.
[0028] The concentration of hydrogen peroxide in the liquid portion
of the wash liquor is preferably 0.1 to 50 mmol/L, particularly
preferably 1 to 20 mmol/L. The liquid portion of the wash liquor is
then understood to be the portion of the whole wash
liquor--inclusive of the water-insoluble solid particles--that is
obtained when the water-insoluble sold particles are separated out
from the liquid portion by means of centrifuging 8 kg of the wash
liquor, including the water-insoluble solid particles, for five
minutes in a centrifuge having a horizontally-mounted cylindrical
rotating body of 515-mm inner diameter and 370-mm inner depth, at
1500 rotations per minute.
[0029] Due to the isolated treatment of the washing suds in the
decoloration device, which is accessible only for the wash liquor
and optionally the water-insoluble solid particles, but not for
textile substrates, and due to the short lifespan of the free
radicals, it is not possible for the UV radiation and/or the free
radicals to act directly on the textile substrates and cause any
damage thereto, for example, by decoloration.
[0030] A quartz lamp or a UV light-emitting diode may be used as
the UV radiation source. However, other UV radiation sources are
also conceivable, such as sunlight, gas discharge lamps,
fluorescent lamps, LEDS, or lasers.
[0031] If a UV radiation source is provided as an activator, it is
generally preferable for this source to be placed in the
decoloration device in such a manner--and/or for the decoloration
device to be designed in such a manner--that the washing chamber is
not exposed to any direct UV radiation, more preferably, is not
exposed to any UV radiation, so that dyes in the textile
substrates, which may be present in the washing chamber, are not
damaged. This can be done, for example, by having an aperture or a
curve present at the entrance and exit in the direction of the
washing chamber, forcing the wash liquor to flow through the
aperture or around the curve. For example, the entrance and exit of
the decoloration device may present as arranged in one direction,
and thus not the direction of the washing chamber.
[0032] The preferred wavelength range of the emitted UV radiation
is between 100 and 400 nm, particularly preferably between 250 and
400 nm. Initial tests indicate that there is a dependency between
the wavelength of the emitted radiation and the type of
decomposable dye. In addition to irradiation with a continuum, it
shall be readily understood that it is also possible to irradiate
discontinuously with UV, as well as to irradiate with one or more
discrete wavelengths.
[0033] According to another embodiment of the washing machine
according to the present invention, beyond the pump generally
provided in a washing machine, at least one additional pump may be
provided, which pumps the wash liquor out from the washing chamber
into the decoloration device and/or out therefrom. This enables a
more efficient design of the decoloration process.
[0034] The use, intensity, and duration of the process for forming
free radicals in the decoloration device are preferably adjustable.
Thus, the use of the process may be coupled to the fulfillment of
certain operating parameters, e.g., to a certain temperature of the
wash liquor or to a certain phase of the wash cycle. For a
temperature-dependent control, a temperature sensor may be
provided, as an example, by which the temperature of the wash
liquor can be ascertained. A purely time-based control may also be
provided, where the process starts at a presettable time.
[0035] Similarly, the duration of the process may be set so that
the process stops as soon as the dye within the wash liquor falls
below a certain quantity. In wash cycles having a particularly low
temperature, during which there is no fear of washing out of dyes
into the wash liquor, the use of the process may also be stopped
entirely. At high wash temperatures and during washing of textile
substrates that especially readily lose color, the intensity and
duration of the process can be increased accordingly.
[0036] The temperature of the wash liquor at which the washing
machine according to the present invention can be operated may be
between 10.degree. C. and 100.degree. C., preferably between
20.degree. C. and 60.degree. C.
[0037] The decoloration device may be fixedly incorporated into a
housing of the washing machine, according to one embodiment of the
present invention. Here, the voltage supply for the activator and
optionally for the pump may be coupled to the voltage supply of the
washing machine. The decoloration device may, for example, be
attached underneath the drum, or on the inside of the door of the
washing machine. For the intake of the wash liquor into the
decoloration device and back out therefrom, corresponding lines may
be provided in the washing machine, which lines can be connected to
the inlet or outlet of the decoloration device. Thus, for example,
the washing chamber may have a wash liquor outlet that can be
connected to the inlet of the decoloration device. Correspondingly,
the outlet of the decoloration device may be connectable to a wash
liquor inlet of the washing chamber, so that the treated wash
liquor can be guided out from the decoloration device back into the
washing chamber. In another embodiment, however, the decoloration
device may also be integrated into the pumping circuit that is
generally present.
[0038] Alternatively, the decoloration device may also be
configured as a separate, preferably battery-operated module. This
module may, for example, be attached to the inner side of the door
of the washing machine with the aid of a corresponding holder. The
advantage of a module that can be introduced separately is that the
module need only be used when necessary, and can thus be subjected
to less wear. Moreover, a separate module can also be introduced
after the fact, even in an already existing washing machine, or can
be taken out from a defective washing machine and introduced into a
new washing machine.
[0039] A special feature of UV radiation is that UV radiation also
has a germ-killing effect in a wavelength range of 200 to 300 nm.
This makes it possible to deactivate microorganisms such as
bacteria, viruses, and protozoa. Thanks to this capability, UV
radiation has been widely applied as an eco-friendly,
chemical-free, and highly effective method for disinfecting water.
Moreover, UV radiation is used to protect water from harmful
microorganisms.
[0040] In contrast to chemical-based methods for disinfecting
water, irradiation with UV is based on a physical process by which
microorganisms are quickly and effectively deactivated. When
subjected to the germicidal wavelengths of UV radiation, then
bacteria, viruses, and protozoa lose the ability to reproduce and
infect.
[0041] UV radiation has proven to be highly effective against
pathogenic organisms including the causative agents of cholera,
polio, typhoid, hepatitis, and other bacterial, viral, and
parasitic diseases. Therefore, according to the present invention,
UV radiation (alone or in combination with hydrogen peroxide) is
used for UV oxidation, a process during which the number of
microorganisms on the textile substrates and/or the water-insoluble
solid particles and/or in the liquid phase of the wash liquor is
reduced considerably.
[0042] Even photocatalytic water splitting is made possible
according to the present invention by the use of short-wave UV
radiation in the range of 250 to 300 nm, with use of suitable
photocatalysts. These photocatalysts are added either to the
detergent or to the water-insoluble solid particles, or may be
composed partially or entirely thereof. It is also possible to
introduce these photocatalysts so as to reside stationarily in the
decoloration device. It is thus basically possible to forgo the use
of quantities of hydrogen peroxide, due to the detergent or to
hydrogen peroxide-generating components.
[0043] The present invention thus also discloses a module that: can
be inserted into a washing machine; has a decoloration device
having an inlet for introducing wash liquor into the decoloration
device and an outlet for discharging the wash liquor out from the
decoloration device; and that has at least one electrochemical
activator that is suitable for initiating, within the decoloration
device, a process for forming free radicals in the wash liquor.
[0044] An essential feature of the washing machine according to the
present invention is the presence of the decoloration device, which
is integrated into the method above, as well as the aforementioned
water-insoluble solid particles and a reservoir for the
particles.
[0045] The washing machine according to the present invention
typically has a hinged door in a housing, in order to make it
possible to access the interior of the washing drum to provide an
essentially closed system. Preferably, the door closes a window of
the stationary, cylindrical drum, which is rotatably mounted within
another drum, while the rotatably-mounted cylindrical drum is
attached vertically within the housing. As a result, a
front-loading device is preferred. Alternatively, the stationary
cylindrical drum may be attached vertically within the housing, the
access device then being located on the upper side of the
device.
[0046] The washing machine is suitable for contacting the particles
with the soiled substrate. Ideally, these particles are effectively
circulated in order to promote effective cleaning.
[0047] According to the present invention, the washing machine
comprises at least one reservoir, in particular, having a
corresponding controller for the water-insoluble solid particles,
the reservoir being located, for example, within the washing
machine and suitable for controlling the flow of the particles
within the washing machine, and containing the particles for
regeneration.
[0048] In another embodiment, the present invention relates also to
a method for washing textile substrates by using the above-defined
washing machine, comprising the steps of: [0049] filling the
washing chamber of the washing machine with the textile substrates
to be washed; [0050] starting a wash cycle; [0051] washing the
laundry by bringing the textile substrates into contact with water,
a detergent, and a large number of water-insoluble solid particles,
and introducing wash liquor from the washing chamber into the
decoloration device (3); [0052] treating the wash liquor in the
decoloration device by using the electrochemical activator; and
[0053] discharging the treated wash liquor from the decoloration
device (3) into the washing chamber, wherein the introducing and/or
discharging of the wash liquor and the treatment of the wash liquor
in the decoloration device may be performed continuously,
discontinuously, or sequentially.
[0054] The functions of the decoloration device shall now be
described in further detail, with reference to FIG. 1.
[0055] Below, the present invention shall be described in further
detail with reference to embodiments and to accompanying drawings,
which illustrate a schematic depiction of an embodiment of the
decoloration device. The functions of the decoloration device shall
be described in greater detail first.
[0056] FIG. 1 illustrates an embodiment of a decoloration device
according to the present invention--referred to as a whole by the
reference sign (3)--which is suitable for receiving wash liquor.
For this purpose, the decoloration device (3) has an inlet (4) and
an outlet (5). Wash liquor (not shown) can pass through the inlet
(4) from the vicinity of the decoloration device (3) into the
internal space thereof. Via the outlet (5), the wash liquor can
then emerge back out from the decoloration device (3). The
direction of flow of the wash liquor is indicated schematically
with arrows.
[0057] An electrode arrangement (7) is arranged within the
decoloration device (3). The arrangement of the electrode
arrangement (7) within the decoloration device (3) is depicted only
schematically in FIG. 1; in particular, any depiction of the
electrical connections has been omitted. The electrode arrangement
(7) comprises an anode (8) and a cathode (9). The anode (8) is
connected to the positive pole of an electrical direct current
voltage source (10), and the cathode (9) is connected to the
negative pole thereof. The anode (8) may be a boron-doped diamond
anode, and the cathode (9) may be a stainless steel electrode. The
direct current voltage source (10) delivers a voltage of, for
example, 2.4 volts.
[0058] If now wash liquor enriched with dyes or rinse water
containing water-insoluble solid particles enters the decoloration
device (3) via the inlet (4), then there is electrochemical
splitting of the water contained in the wash liquor or rinse water.
This results in hydroxyl radicals, that interact with and break
down the dyes contained in the wash liquor or rinse water. The
decolored wash liquor or rinse water is finally guided back out of
the decoloration reservoir (3) via the outlet (5).
[0059] The terms "decolored wash liquor" or "rinse water" are
intended to signify, according to the present invention, that the
dye content of the wash liquor or rinse water--inclusive of the
particles--is significantly lower on leaving the decoloration
device 3 than on entering the decoloration device (3). The absolute
degree of decoloration is dependent on a variety of parameters,
such as the original dye content in the wash liquor, the residence
time of the wash liquor in the decoloration device (3), the
voltage, the current intensity, and the like.
[0060] Moreover, the decoloration device according to the present
invention may additionally comprise a UV radiation source (not
shown). If now a wash liquor (optionally containing hydrogen
peroxide (H.sub.2O.sub.2)) in which dyes are dissolved is
introduced through the inlet (4) into the decoloration device (3),
then H.sub.2O.sub.2 molecules are activated by UV radiation emitted
by the optionally additionally present quartz lamp, producing
short-lived, highly-reactive hydroxyl radicals (OH). These OH
radicals attack and break down the dyes dissolved in the washing
liquid. The washing liquid, having been thus decolored, is then
guided through the outlet (5) back out from the decoloration
reservoir (3).
[0061] The washing machine according to the present invention,
which comprises a decoloration device (3), and the method executed
therewith to washing textile substrates thus represent an approach
with the aid of which the risk of discoloration during the washing
process in a washing machine can be minimized. In particular, the
present invention is characterized in that a wide range of dyes can
easily be broken down at the same time, without adverse effects on
the textile substrates themselves caused by the color
neutralization process. As a consequence of this reduced risk of
discoloration, it is possible to largely forgo pre-sorting of
textiles by colors prior to the wash, which represents significant
time savings.
[0062] Another aspect of the present invention encompasses a method
for cleaning a soiled textile substrate, wherein the method
includes treating the wet substrate with a formulation that
includes a large number of water-insoluble solid particles, wherein
the particles are optionally reused after a regeneration with or
without use of a detergent in further cleaning processes according
to the method.
[0063] Optionally, the water-insoluble solid particles may be
exposed to a voltage through the electrode arrangement alone, or
optionally in combination with UV radiation, for the purpose of
regeneration in the decoloration device during the wash cycle or in
a separate step.
[0064] According to the present invention, the substrate to be
cleaned encompasses textile substrates, each optionally from a
variety of materials, which may be either natural fibers such as
cotton, or synthetic textile fibers such as Nylon 6.6 or a
polyester.
[0065] The water-insoluble solid particles may be inorganic and/or
organic in nature. The solid particles particularly preferably
entail, for example, zeolites, clays, or ceramics. The particles
may exhibit a certain level of hydrophilicity, in order to enable
wetting with the wash liquor.
[0066] The organic water-insoluble solid particles may encompass
any of a large number of different polymers. Particularly preferred
are polyalkenes such as polyethylene and polypropylene, polyesters,
and polyurethanes. However, the polymer particles are preferably
made of polyamide, especially particles made of nylon, most
preferably in the form of nylon chips. The polyamides are
particularly effective for aqueous stain/dirt removal, whereas
polyalkenes are particularly useful for removing oil-containing
stains. Optionally, copolymers of the above polymeric materials may
be used for the purposes of the present invention.
[0067] Different nylon homopolymers or copolymers may be used,
including Nylon 6 and Nylon 6.6. Preferably, the polyamide
encompasses Nylon 6.6 homopolymer having a mean molecular weight in
the range of 5,000 to 30,000 daltons, preferably 10,000 to 20,000
daltons, most preferably 15,000 to 16,000 daltons. The mean molar
masses set forth here and hereinbelow, optionally, for other
polymeric components refer to weight-average molar masses M.sub.w,
which can basically be determined by means of gel permeation
chromatography with the aid of an RI detector, the measurement
advantageously being performed against an external standard.
[0068] The water-insoluble solid particles or granulate, particles,
or molded bodies are of such a shape and size as to enable
favorable flowability and close contact with the textile substrate.
Preferred shapes of the particles include spheres and cubes, but
the preferred particle shape is cylindrical. The particles are
preferably dimensioned so as to each have a mean weight in the
range of 20 to 50 mg, preferably 30 to 40 mg. In the case of the
most preferred cylindrically-shaped particles, the preferred mean
particle diameter is 1.5 to 6.0 mm, particularly preferably 2.0 to
5.0 mm, most preferably 2.5 to 4.5 mm, whereas the length of the
cylindrical particles is preferably in the range of 2.0 to 6.0 mm,
particularly preferably 3.0 to 5.0 mm, and most preferably in the
range of 4.0 mm.
[0069] Prior to the cleaning, the textile substrate is preferably
moistened by wetting with water, in order to provide additional
improvement for the wash liquor and thereby improve the transport
properties within the system (pre-treatment). This facilitates a
more efficient transfer of the detergent to the substrate and
removal of dirt and stains from the substrate. Most conveniently,
the substrate may be wetted by contact with tap water. Preferably,
the wetting treatment is performed in order to achieve a
substrate-to-water weight ratio of 1:0.1 to 1:5; the ratio more
preferably lies between 1:0.2 and 1:2, wherein particularly
favorable results are obtained with ratios such as 1:0.2, 1:1, and
1:2. However, in some cases, successful results may be achieved
with the substrate-to-water ratio up to 1:50, although such ratios
are not preferred in terms of the significant amounts of wastewater
generated.
[0070] In the method according to this aspect of the present
invention, which can be regarded as an interstitial method between
cleaning and scouring, a weight ratio of textile substrate to
water-insoluble solid particles is adjusted in the range of 1:1 to
1:30, in particular, 1:1.5 to 1:2.5, especially 1:2. Then, the
proportion of water-insoluble solid particles is determined as the
weight of the particles in the dry state, i.e., after 24 hours of
storage at 21.degree. C. and a relative humidity of 65%.
[0071] In addition, it has been shown that the water-insoluble
solid particles can be regenerated, and that the particles can be
satisfactorily used anew in the cleaning method, although a certain
deterioration in performance is generally observed at three uses of
the particles. When the particles are used anew, optimal results
are obtained when the particles are coated anew prior to being
reused with the detergent.
[0072] The water-insoluble solid particles can be regenerated in a
known manner, such as, for example, is described in WO 2012/035342
A1. In the context of the present invention, the regeneration is
performed by introducing the particles, optionally with the
detergent, into the decoloration device, e.g., in a separate rinse
cycle, optionally through addition of cleaning agents that may also
be aggressive in nature. The temperature of the regeneration step
is independent of the wash temperature, if the textile substrate is
taken out from the washing machine prior to the regeneration.
Furthermore, the usual detergent raw materials may be used.
[0073] While at least one exemplary embodiment has been presented
in the foregoing detailed description of the invention, it should
be appreciated that a vast number of variations exist. It should
also be appreciated that the exemplary embodiment or exemplary
embodiments are only examples, and are not intended to limit the
scope, applicability, or configuration of the invention in any way.
Rather, the foregoing detailed description will provide those
skilled in the art with a convenient road map for implementing an
exemplary embodiment of the invention, it being understood that
various changes may be made in the function and arrangement of
elements described in an exemplary embodiment without departing
from the scope of the invention as set forth in the appended claims
and their legal equivalents.
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