GB2029469A - Winch dyeing - Google Patents

Abstract

Carpets and felts 45 are dyed in a winch machine 29 which includes a jet bar 13 for directing a jet of dye liq. against the carpet or felt below the surface 49 of the dyebath 33 as the carpet or felt leaves the dyebath, dyestuff being a added at 39 to the liq. drawn from the bath via line 37. <IMAGE>

Description

SPECIFICATION Method of winch dyeing and equipment for use therein This invention relates to a method of winch dyeing, to an improved winch dyeing machine and to a jet bar for use in such a machine.

According to a first feature of the present invention we provide a method for dyeing a textile material in web form with a dyestuff which comprises circulating the web in a winch dyeing machine containing a dyebath liquor from which the dyestuff has been omitted at an appropriate temperature for dyeing the textile material with the dyestuff and directing at the textile material as it passes through the dyebath liquor a current, extending evenly across the width of the textile material, of a liquid containing the dyestuff.

The current of the liquid containing the dyestuff is preferably directed at the textile material just below the surface of the dyeing liquor in the winch dyeing machine and just before the textile material passes out of the dyebath liquor.

The current of liquid preferably comprises the dyebath liquor, from the winch dyeing machine, and a concentrated solution or suspension of the dyestuff. The current may be provided by circulating the dyebath liquor through a circulation pipeline and a jet bar, submerged within the dyebath liquor and capable of directing the liquor into a current, the solution or suspension of dyestuff being introduced into the circulating dyebath liquor as it passes through the circulation pipe.

The method is particularly suitable for the dyeing of dimensionally stable textile materials, such as carpets and felts, because there is a tendency for other, more flexible, textile materials to form lateral folds and thus not to take up the dyestuff from the current in an even manner.

A current which is irregular or uneven across its width can lead to uneven take-up of the dyestuff and thus to stripiness along the direction of motion of the textile material.

It has been found using this process that most of the dyestuff is absorbed immediately by the textile material, that the concentration of dye in the dyebath liquor rarely exceeds about 10-20% of that required at the start of a normal winch dyeing process, and that the textile material can be evenly dyed.

Sufficient dyestuff is added in this manner to achieve the desired depth of shade on the substrate. After dyestuff addition is complete, dyeing is only continued for a short period typically about 10-15 minutes during which the substrate takes up some of the residual dyestuff from the dyebath liquor and reaches the desired depth of shade. The method thus permits a greatly reduced dyeing time because the winch can be heated as rapidly as the heating means allows instead of being heated at a rate governed by the dyeing process and the dyeing process itself only lasts about as long as is required to add the dyestuff.

According to a second feature of the present invention there is provided an improved winch dyeing machine comprising a liquor bath, a winch for circulating a continuous web of textile material through the liquor bath, means for heating the contents of the liquor bath, a jet bar capable of providing a current of liquid extending evenly across the working width of the winch and of being positioned below the normal liquor level in the liquor bath, a circulation system for circulating liquor from the liquor bath through the jet bar and thence back into the liquor bath and means for adding a liquid containing a dyestuff into the circulation system.

A preferred form of jet bar, which forms a third feature of the present invention comprises a tubular shroud having a longitudinal slot and distribution means within the shroud for directing liquid at the inner wall of the shroud, along the length of the slot, in a direction rotationally displaced from the slot whereby liquid may be directed at the inner wall of the shroud and, during passage round the inner surface of the shroud, be diffused and caused to issue in a planar jet through the slot.

When the jet bar is immersed in a second liquid the planar jet becomes a current of the first liquid through the second liquid.

The distribution means is preferably a second inner tube within the shroud having (i) a line of holes, or a narrow longitudinal slit rotationally displaced from the slot in the shroud, and (ii) means for connection to a source of liquid.

The circulation system conveniently comprises a pipeline containing a pump leading from the liquor bath to the distribution means of the jet bar whereby the dyeing liquor may be circulated through the jet bar and back into the bath.

The dyestuff addition means conveniently comprises a dyestuff liquid storage vessel, connected to the recirculation pipeline by a pipe and a dosing pump.

In operation the liquor bath of the winch dyeing machine is filled with a dyebath liquor, containing all the dyeing ingredients except for the dyestuff, in the normal manner and a concentrated solution of the dyestuff is placed in the storage vessel. The jet bar is suspended below the liquor level and preferably in such a position that the current of liquid is directed at the circulating textile material just before it passes out of the dyebath liquor. The dyebath liquor may be heated to the dyeing temperature as quickly as the heating means will permit and circulation of dyebath liquor through the circulation system and jet bar commenced. When the dyeing temperature is reached, dye solution from the storage vessel is conveniently dosed into the circulation pipe at approximately the rate at which dye is adsorbed by the textile material.This rate will depend on the nature of the textile material and the dyestuff and on the conditions of, for example, pH and temperature in the dyebath liquor. Under optimum conditions the dyestuff can be added over a period of 25 to 30 minutes during which most of the dyestuff is adsorbed by the textile material directly from the current of dyebath liquor emanating from the jet. In order to avoid dyestuff wastage, it is desirable to continue circulation of the textile material and the dyestuff liquor for a short period, normally about 10-15 minutes, after addition of the required quantity of dyestuff to the circulating dyebath liquor is complete, in order to allow the textile material to take up unabsorbed dyestuff which has become diffused throughout the dyebath liquor.

It is desirable to maintain the textile material as close as possible to the jet bar and to prevent motion of the textile material towards or away from the jet bar in order to minimise diffusion of the dyestuff throughout the dyebath liquor. Lateral stability of the textile material in relation to the jet bar may be achieved by maintaining it constantly in contact with the shroud.

The invention will be further illustrated by reference to the accompanying drawings which show a jet bar and part of a winch dyeing machine according to the present invention. In the drawings, Figure 1 shows a jet bar according to the present invention partly cut away; Figure 2 shows a section through part of a winch dyeing machine adapted to perform the method of the present invention and containing the jet bar shown in Fig. 1.

In the drawings the jet bar 11 comprises a tubular shroud 1 3 having closed ends 1 5 and a longitudinal slot 1 7. Mounted eccentrically within the shroud 1 3 and on the opposite side of the longitudinal axis from the slot 1 7 is an inner tube 1 9 having closed ends 20 and two side arms 21 which extend through the shroud 1 3. The inner tube 1 9 has a line of small holes 23 at regular intervals along its length directed at the inner surface of the shroud so that liquid emanating in jets from the holes 23 is diffused and directed around the inner surface of the shroud 1 3 and out through the slot 1 7 in a substantially tangential direction (illustrated by arrows 25).

A line of small holes 27 is formed in the shroud 1 3 to allow air in the shroud to escape as the jet bar 11 is lowered into the liquor contained in a winch dyeing machine 29.

A support frame 31 attached to the jet bar 11 allows it to be supported from the winch dyeing machine 29.

The winch dyeing machine is provided with the usual liquor bath 33 and an upper bar 35 over which the textile material 45 passes to the winch (not shown) in the direction shown by arrow 46.

A circulation system comprises a circulation pipe line 37, leading from the liquor bath 33 into both side arms 21, and containing a circulation pump 36. A pipe 39 leading into the circulation pipe line 37, from a storage vessel 41, contains a dosing pump 43.

In operation the liquor bath 33 is filled with water, containing all the usual dyebath ingredients except for the dyestuff, to level 49. The jet bar 11 is supported in the liquor as shown in Fig. 2 below the upper bar 35.

A carpet to be dyed 45 is fitted into the winch dyeing machine and circulated through the liquor in the normal manner.

The liquor is circulated through the jet bar 11 via pipe line 37 by pump 38 and heated as rapidly as possible to the dyeing temperature, normally 90-100"C for a wool or nylon carpet. A concentrated solution of dyestuff, containing sufficient to dye the carpet to the required depth of shade is then fed from the storage vessel 41, into the circulating liquor in pipeline 37, via pipe 39 and dosing pump 43 over a period of 20 to 30 minutes. In this way the carpet 45 is evenly dyed to the required depth of shade.

When the required quantity of dyestuff has been added, feed of the dyestuff is discontinued but circulation of the carpet and the dyebath liquor is continued for about 10 to 1 5 minutes in order to take up dyestuff which has been distributed throughout the dyebath liquor until the required depth of shade is achieved. The carpet is then processed further according to normal practice.

If there is a tendency for the carpet to move laterally towards or away from the jet bar, it is desirable to provide means for preventing such movement and maintaining the carpet against the shroud. Such means may conveniently comprise a roller placed just below the jet bar and biased against the reverse side of the carpet.

Example In this Example a carpet is dyed using a winch dyeing machine as described hereinbefore with reference to Figs. 1 and 2, the various parts of the machine having the capacities indicated in brackets.

The liquor bath (100 litres) of the winch dyeing machine 29 is filled with 100 litres of water containing 1 %, by weight, of a levelling agent (Matexil LA NS obtainable from Imperial Chemical Industries Ltd) and 3%, by weight, of a pH controlling agent (ammonium acetate) and a length of carpet (2.5 kilograms) is fitted around the winch. A dyeing liquor comprising 3+ grams of Nylomine Yellow A4R, 3 gram of Nylomine Red AB and 3 gram of Nylomine Blue AG in 4 < litres of water is placed in the storage vessel 41.

The temperature of the solution in the liquor bath 33 is raised to the boiling point as quickly as possible (2"C/min) and during the heating up period the solution is circulated through the jet bar 11 by means of the circulation pump 36 (100 litres/hour). When the temperature of the solution is 80"C the dosing pump (12 litres/hour) is started and the dyeing liquor added to the circulating solution over a period of 20 minutes. Circulation is continued for a further period of 10 minutes after addition of the dyeing liquor is complete after which the carpet is removed from the winch and washed in a conventional manner.

The shade and levelness of the dyeing produced by this methos is equal to that produced using the conventional technique, i.e. adding the dyestuff to the winch before dyeing commences, heating the dye liquor to the boil at a rate of 1"C/min. and maintaining the dyeing liquor at the boil for 30 minutes.

The present method thus reduces the dyeing time from 90 minutes to 60 minutes without any deterioration in the quality of the dyeing.

If the dyeing liquor is added directly to the liquor bath 33 when the solution is at the boil without the use of the jet bar 11, in order to reduce the dyeing time to 60 minutes, the levelness of the dyeing is well below commercially acceptable standards.

Claims (8)

1. A method for dyeing a textile material in web form with a dyestuff which comprises circulating the web in a winch dyeing machine containing a dyebath liquor, from which the dyestuff has been omitted, at an appropriate temperature for dyeing the textile material with the dyestuff, and directing at the textile material, as it passes through the dyebath liquor, a current, extending evenly across the width of the textile material, of a liquid containing the dyestuff.

2. A method according to Claim 1 wherein the current of liquid containing the dyestuff is directed at the textile material immediately below the surface of the dyebath liquor as the textile material is about to pass out of the dyebath liquor.

3. A method according to Claim 1 or Claim 2 wherein the current of liquid comprises a mixture of the dyebath liquor and a concentrated solution or suspension of the dyestuff.

4. A method according to Claim 3 wherein the current of liquid is provided by circulating the dyebath liquor through a pipe and a jet bar, submerged within the dyebath liquor and capable of providing a current of liquid extending evenly across the width of the textile material, and adding the concentrated solution or suspension of dyestuff to the dyebath liquor as it passes through the pipe.

5. A method according to any one of Claims 1 to 4 wherein the textile material is a carpet.

6. A winch dyeing machine which comprises a liquor bath, a winch for circulating a continuous web of a textile material through the liquor bath, means for heating the contents of the liquor bath, a jet bar capable of providing a planar jet of liquid extending evenly across the working width of the winch and of being positioned below the normal liquor level in the liquor bath, a circulation system for introducing liquor from the liquor bath into the jet bar and means for adding a liquid, containing a dyestuff, into the circulation system.

7. A jet bar for use in a winch dyeing machine according to Claim 5 which comprises a tubular shroud having a longitudinal slot and distribution means within the shroud for directing liquid at the inner wall of the shroud, along the length of the slot, in a direction rotationally displaced from the slot whereby liquid may be directed at the inner wall of the shroud and, during passage round the inner surface of the shroud, become diffused and caused to issue in a planar jet through the slot.

8. A jet bar according to Claim 7 wherein the distribution means comprises a second tube situated within the shroud having (i) a line of holes or a narrow longitudinal slit rotationally displaced from the slot in the shroud and (ii) a connection piece for introducing a liquid into the second tube.