Textile treatment process

Disclosed is a textile treatment process wherein a substrate is supported on one or more arms above a treatment liquor and is passed repeatedly through such liquor, characterised in that at least a part of that part of the substrate supported on the arm or arms and out of contact with the treatment liquor at any given time is heated employing heated air or steam, and that the liquor to goods ratio is in the range of from 5:1 to 15:1, and an apparatus suitable for performing such process.

The present invention relates to an improved process and apparatus for use 
in textile treatments carried out on winch-beck and like devices. 
Hitherto, processes employing winch-beck and like devices involve the 
support of the substrate, generally in endless form, on one or more 
horizontal arms, drive being applied to the substrate to convey same over 
the arm(s) and pass it repeatedly through a trough or sump of treatment 
liquor located below the arms. In general, at any given time the 
predominant part of the substrate is in contact with the liquor in the 
sump and only a small part, about 10%, is supported out of the liquor by 
the arms. Heat is applied to the liquor in the sump, either by means of 
heat exchangers in the liquor or by heating the sump itself. The 
maintenance of an even temperature in and throughout the liquor is 
generally effected by passage of the substrate or with the aid of rotary 
pumps. The maintenance and regulation of the liquor temperature need 
somewhat complex apparatus and technology for optimum results to be 
achieved. Additionally or alternatively, the effects of temperature 
irregularities, generally non-uniform dyeing, are compensated by 
increasing dyeing times. The liquor to goods ratio in such processes is 
generally of the order of from 15:1 to 40:1. 
The process of the present invention is a radical departure from the 
above-described process.

Thus, according to the present invention, there is provided a textile 
treatment process wherein the substrate is supported on one or more arms 
above a treatment liquor and is passed repeatedly through such liquor, 
characterized in that at least a part of that part of the substrate 
supported on the arm or arms and out of contact with the treatment liquor 
at any given time is heated employing heated air or steam, and in that the 
liquor to goods ratio is in the range of from 5:1 to 15:1, preferably 5:1 
to 10:1. 
The radical departure of the process of the present invention from hitherto 
known processes lies in the fact that heat is applied to the substrate 
rather than to the liquor. If desired, of course, in the process of the 
invention, heat can heated air or steam, and in that the liquor to goods 
ratio is in the range of from 5:1 to 15:1, preferably 5:1 to 10:1. 
The radical departure of the process of the present invention from hitherto 
known processes lies in the fact that heat is applied to the substrate 
rather than to the liquor. If desired, of course, in the process of the 
invention, heat can additionally be applied to the liquor, although this 
is not preferred. In the process of the invention, during the course of 
treatment, the liquor becomes heated by the passage therethrough of the 
heated substrate and this has been found to be sufficient, the low liquor 
to goods ratio being conducive to achievement of uniform temperature 
throughout the liquor at any given time and to a relatively steep rise in 
temperature of the liquor. The substrate is, of course, preferably heated 
uniformly across its full width. 
If desired, as a preliminary step in the process of the invention, the 
textile substrate may be wetted out, preferably as uniformly as possible, 
with water. Also, if desired, the substrate may be pre-heated to stabilize 
the fibres, this conveniently being carried out in a "dry-run" i.e. 
without liquor present, the substrate, for example being conveyed over the 
arm(s) and through a dry liquor sump, whilst being heated, preferably with 
steam. 
During the process of the invention the temperature of the substrate is 
preferably caused, by the application of the heated air or steam, to be 
raised to the temperature at which the components in the treatment liquor 
perform their function, e.g. in the case of dyeing or optical brightening, 
to the temperature of fixation of the dye or brightener. In general, and 
in a preferred mode of operation, during progress of the process of the 
invention, the heated air or steam gradually heats the substrate which, in 
turn, gradually heats the treatment liquor, the temperature differential 
between air or steam, substrate and liquor gradually diminishing during 
the treatment time until a stage is reached where a substantially uniform 
temperature is present throughout all three, which temperature is 
preferably in the range at which the components in the liquor perform 
their function. This mode of operation is illustrated in the graph shown 
in FIG. 2 of the accompanying drawings where temperature, in degrees 
centigrade, is plotted against time, in minutes, curve 1 being in respect 
of the steam or heated air (or rather of the atmosphere around the 
substrate supported on the arms), curve 2 being in respect of the 
substrate and curve 3 being in respect of the treatment liquor. As will be 
appreciated, the times and temperatures given in the graph are only 
illustrative and may be varied depending on the particular process being 
carried out. 
As will be appreciated, the process of the invention is preferably carried 
out employing a closed housing or hood, i.e. a housing or hood which 
enables the heated air or steam to be contained around the substrate while 
the latter is supported on the arm(s). Absolute closure of the housing or 
hood is, of course, not necessary, and indeed one or more openings to 
facilitate air or steam circulation or to act as vents are desirable. The 
term "closed housing or hood" is to be understood accordingly. Such 
housings are generally employed in winch-beck textile treatment processes. 
In general, in the process of the invention, an envelope of heated air or 
steam is caused to surround at least a part, preferably a predominant 
part, of that part of the substrate supported out of the treatment liquor, 
and extend across the full width of the substrate. 
The invention further provides an apparatus suitable for performing the 
process of the invention, which apparatus comprises a sump or trough to 
hold a treatment liquor, one or more arms located above the sump or trough 
for support of a textile substrate, means for applying drive to the 
substrate to cause same to be conveyed over said arm(s) and through said 
sump or trough, a closed housing or hood to partially define a zone 
surrounding said arm(s) and at least a part of the path of the substrate 
when supported on said arm(s), one or more inlets for the supply of steam 
or heated air into said zone, and one or more temperature sensors located 
in said zone and coupled to means for controlling the ingress of steam or 
heated air into said zone. 
Preferably, and as is conventional in the winch-beck dyeing art, the 
housing or hood and sump are joined or integral, that is to say together 
form a closed chamber. The term closed chamber is to be understood, in 
like manner. to closed housing or hood, not to be limited to absolute 
closure. 
The temperature sensor(s) located in the zone defined by the housing or 
hood enable(s) monitoring of the temperature in the zone and is(are) 
preferably linked to a regulating device operable on the steam or hot air 
inlet(s) or source, to control same in order to regulate the temperature 
in the zone, e.g. according to a desired or predetermined value or 
pattern. Preferably two such sensors are employed, a first preferably in a 
location relatively removed from the sump or trough (generally in the 
upper region of the zone defined by the housing or hood) and one 
preferably in a location relatively close to the sump or trough (generally 
in the lower region of the zone defined by the housing or hood). The 
second mentioned temperature sensor is preferably arranged to act 
primarily as a hot air or steam sensor to detect and control the lower 
level of the hot air or steam at least during the initial phases of the 
treatment process when it is of advantage to maintain a distance between 
the heated zone and the treatment liquor. As the temperature of the air or 
steam, substrate and liquor reach equilibrium, this separation between the 
heated zone and the liquor generally disappears. 
One embodiment of an apparatus according to the invention will now be 
described with reference to FIG. 1 of the accompanying drawings. 
The apparatus is a modified conventional winch-beck dyeing apparatus in 
that in common with such apparatus it comprises two horizontally arranged 
winch arms 5 and 10 mounted in a closed chamber, the lower part of which 
chamber forms a sump for the liquor 6, the upper part of which forming a 
housing or hood surrounding the winch arms and path of substrate 11 when 
the substrate is supported on the winch arms. The direction of passage of 
the substrate is shown by the arrows. A controllable vent 2 is located in 
the roof of the chamber. 
Unlike conventional winch-beck dyeing apparatus, however, the shown 
embodiment of the invention is not provided with any heating means for the 
sump, although such may be present but left inoperative. Instead, it 
comprises two steam or hot air inlets 3 and 4 which extend across the 
width of the chamber and two temperature sensors 1 and 7, sensor 1 being 
located adjacent the roof of the chamber, sensor 7 being located towards 
the bottom of the chamber but above the liquor level in the sump. A cold 
water sprinkler 8 is located adjacent the path of the substrate and 
extends across the width of the substrate. 
In operation according to a preferred mode of the process of the invention, 
hot air or steam is let into the chamber through inlets 3 or 4 whilst the 
substrate is conveyed, preferably at a speed within the range of from 20 
to 150 m/min, over winch arms 5 and 10 (one of which is driven) and 
transported through the liquor in the sump of the chamber. As the 
temperature rises in the zone surrounding the entrained substrate this is 
monitored by sensor 1 which, through a feedback device, is coupled to the 
inlets 3 and 4 (or alternatively to the source of hot air or steam) to 
control the temperature as desired. As the steam or hot air builds up in 
the upper part of the chamber the lower level of steam or hot air descends 
to a level 9, a short distance above the liquor 6, where it is detected by 
sensor 7. In the initial phases of the process, the lower level of steam 
or hot air is preferably maintained at this level 9, the sensor 7 being 
connected to a device for controlling the inlets 3 and 4 and the vent 2 
and either more steam or air being fed into the chamber or some allowed to 
escape through vent 2 depending on whether the level 9 rises or falls. 
During this phase of operation the temperature of the substrate rises and, 
due to its passage through the liquor, the temperature of the liquor 
consequently rises in the manner graphically represented in FIG. 2 of the 
drawings. As time passes, and as explained above, a stage is arrived 
whereat the temperature of the atmosphere around the entrained substrate, 
the temperature of the substrate and the temperature of the liquor become 
uniform, which temperature, in the case of dyeing and optical brightening 
processes, the preferred processes of the invention, lies in the fixation 
temperature range of the dye or brightener. Once this stage is reached 
there is no need to maintain the lower level of the hot air or steam above 
the liquor level and it may be allowed to fall. This "steady state" of 
temperature is then maintained for sufficient time for fixation to take 
place, after which the inlets 3 and 4 can be closed, vent 2 fully opened, 
the spent liquor run off and cold water sprayed onto the substrate from 
sprinkler 8 to cool and rinse the dyed substrate as it continues to be 
driven over arms 5 and 10. 
The liquor employed in the process of the invention may contain, in 
addition to the main components therein e.g. dyestuff or optical 
brightening aids such as carriers and softening agents. It is of 
particular advantage, however, for the liquor to contain a surface active 
agent or the like to facilitate thorough wetting of the substrate. 
As will be appreciated, to avoid or reduce slippage of the goods on the 
winch arms, driven roller pairs may be introduced along the path of the 
substrate. 
Because of the low liquor to goods ratios employed in the process of the 
invention and the consequent lowering of buoyancy given to the substrate 
in the liquor, with some sump designs undue bunching of the substrate can 
occur at that end of the sump where the substrate enters the liquor. This, 
however, can be avoided by use of a ramp or slide sloping towards the 
centre of the sump. 
The process and apparatus provided by the invention are particularly 
suitable for the processing, particularly dyeing, of carpets. 
The process of the invention is further illustrated by the following 
Examples in which the parts and percentages are by weight and the 
temperatures in degrees centigrade. 
EXAMPLE 1 
Carpet material of polyamide 6, having a polypropylene backing is dyed in a 
liquor ratio of 1:8 in a modified carpet winch beck as in FIG. 1. 
The dye liquor used contains the following components per 1000 parts: 
0.1 parts of the dyestuff of the following structural formula 
##STR1## 
0.2 parts of the dyestuff C.I. Acid Red 57 0.4 parts of the dyestuff C.I. 
Acid Blue 288 
0.3 parts of a commercial wetting agent based on a higher alkylbenzene 
sulphonate 
1 part of a mixture of the following components: 
400 parts of benzyl alcohol 
450 parts of monophenylglycol ether 
150 parts of octylphenylpentaglycol ether 
0.05 parts of 60% acetic acid. 
The carpet is moved over the winch and the process carried out as 
hereinbefore described, steam or hot air being fed into the chamber, 
whereby the substrate, over a period of 10 to 60 minutes is heated to a 
temperature between 60.degree. to 100.degree.. After the stage is reached 
whereat the atmosphere, substrate and liquor are at a substantially 
uniform temperature, the temperature is maintained for a further 10 to 60 
minutes for fixation to take place, whereafter the heating is stopped and 
the substrate cooled and rinsed by allowing water to flow in, and spraying 
with water. 
An evenly dyed carpet is obtained. 
EXAMPLE 2 
A polyamide carpet material with a polypropylene backing is dyed in similar 
manner to that described in Example 1, at a liquor to goods ratio of 8:1 
employing a liquor containing, per 1000 parts: 
0.55 parts C.I. Acid Orange 156 
0.3 parts C.I. Acid Red 57 
0.42 parts C.I. Acid Blue 40 
0.6 parts of a commercial foam dampening wetting agent based on a higher 
alkylbenzene sulphonate and 
0.15 parts of 60% acetic acid. 
A level brown dyed carpet results. 
EXAMPLE 3 
A loop pile carpet material of mixed basic and acid dyeable polyamide yarns 
with a polypropylene backing is dyed in similar manner to that set out in 
Example 1 with a liquor containing, per 1000 parts: 
0.26 parts C.I. Acid Orange 145 
0.05 parts C.I. Acid Red 57 
0.1 parts C.I. Acid Blue 72 
0.07 parts C.I. Basic Orange 37 
0.02 parts C.I. Basic Red 23 
0.022 parts C.I. Basic Blue 22 
0.6 parts commercial foam dampening wetting agent based on a higher 
alkylbenzene sulphonate 
0.6 parts commercial wetting agent based on a polyglycol behenylamine 
0.1 part acetic acid 60%. 
A differential level dyed carpet results. 
EXAMPLE 4 
A cut-loop polyamide carpet material with polypropylene backing is dyed 
following the procedure of Example 1 employing a liquor containing, per 
1000 parts: 
0.98 parts C.I. Acid Yellow 219 
0.14 parts C.I. Acid Red 57 
0.11 parts C.I. Acid Blue 40 
0.3 parts commercial wetting agent based on an aromatic sulphonate 
0.1 part acetic acid 60%. 
A level dyed carpet results. 
EXAMPLE 5 
A cut loop mixed polyamide/polyester carpet material with a polypropylene 
backing is dyed in similar manner to Example 1 with a liquor containing, 
per 1000 parts: 
0.04 parts C.I. Disperse Yellow 57 
0.05 parts C.I. Disperse Red 53 
0.02 parts C.I. Disperse Blue 56 
1.0 part commercial highly sulphonated anionic oil sulphonate 
0.5 parts commercial aliphatic polyglycolether. 
A level dyed beige carpet results. 
EXAMPLE 6 
A cup pile polyamide carpet material with a polypropylene backing is dyed 
in similar manner to Example 1 with a liquor containing, per 1000 parts: 
0.6 parts C.I. Acid Yellow 196 
1.0 part C.I. Acid Orange 156 
0.3 parts commercial wetting agent based on an aromatic sulphonate 
0.8 parts softener based on a fatty acid derivative 
0.3 parts acetic acid 60%. 
A soft, voluminous, level dyed carpet results. 
EXAMPLE 7 
A loop pile carpet material of basic dyeable polyamide with a polypropylene 
backing is dyed in similar manner to Example 1 with a liquor containing, 
per 1000 parts: 
0.6 parts C.I. Acid Orange 145 
0.03 parts C.I. Acid Red 57 
0.14 parts C.I. Acid Blue 72 
0.6 parts C.I. Basic Orange 57 
0.7 parts of an acid liberator (.gamma.-butyrolactone) 
0.3 parts commercial wetting agent based on higher alkylbenzene sulphonate 
0.3 parts commercial wetting agent based on a polyglycolated behenylamine. 
A differential, level dyed carpet results. 
EXAMPLE 8 
A cut-pile polyamide carpet with a polypropylene backing was dyed in 
similar manner to that described in Example 1 in a liquor containing, per 
1000 parts: 
0.15 parts C.I. Acid Orange 156 
0.1 parts C.I. Acid Red 57 
0.12 parts C.I. Acid Blue 40 
0.3 parts commercial wetting agent based on an aromatic sulphonate, and 
0.5 parts Borax. 
In this case, however, a liquor to goods ratio of 1:9 was employed and the 
carpet material was repeatedly passed through the liquor whilst 
maintaining the temperature of the atmosphere in the chamber between 
85.degree. and 95.degree. for from 10 to 20 minutes. By addition of 0.7 
parts of .gamma.-butyrolactone to the liquor the desired exhaustion was 
achieved. The carpet then further transported whilst maintaining the 
temperature to effect fixation of the dyeing.