GB2084515A - Method for producing spaced- dyed yarn - Google Patents

Abstract

Yarn is space dyed in a plurality of tones of one colour, by a single set of printing rolls having an intermittent relief pattern of at least two different depths filled with dye. The yarn is formed into a prefabric before passing through the nip of the printing rolls and the space dyed yarn is recovered from the prefabric. In preferred embodiments there may be a background colour applied uniformly, and more than one sort of printing rolls to produce multi-colour effect. <IMAGE>

Description

SPECIFICATION Method for producing space-dyed yarn The present invention relates to an improved method for producing space-dyed yarn and particularly to a method for producing yarn spacedyed in different tones. More particularly, the invention relates to a method for producing spacedyed yarn dyed with different tones of the same colour using only one set of printing rolls for each colour.

It is known that when a continuous yarn dyed in a multicoloured pattern, in which the pattern is repeated frequently, is utilized to prepare a knitted, woven or tufted material, the finished article tends to develop undesirable striations or streaking. The phenomenon is particularly noticeable when multicoloured yarn is utilized for preparing tufted carpeting or upholstery fabric.

To overcome the difficulty of streaking, a technique known as space-dyeing was developed to provide a yarn which was dyed with multiple colours but the pattern of the multiple colours is repeated only at long intervals along the yarn. The long intervals between repeating patterns prevents the development of streaking or striations in the finished article.

Gibson et al. in U.S.A. Patent 3,605,225 disclose the formation of a woven fabric on which diagonal stripes of various colours are then printed followed by the disassembly of the fabric by deweaving it, to produce a multiplicity of multicoloured yarns.

Gibson et al. disclose that the process may be combined with pad dyeing to provide the yarn with an overall background colour but even with this additional step, the number of colours which can be applied to the yarn is limited.

U.S. Patent 4,058,848 to Whitaker discloses a novel method for space dyeing a woven fabric wherein the fabric is prepared by utilizing a sacrificial filling which is dissolved after the space dyeing operation to recover the multicoloured yarn.

Knitted tubing may be subjected to similar processes as disclosed in U.S. Patents 3,012,303, 3,543,359,4,033,717, 3,701,315, 3,919,749 and 4,185,364.

The concept of spaced dyeing has been applied to individual yarns as disclosed in U.S.A. Patent Nos. 3,871,196 and 3,803,880.

It has also been disclosed to knit textile yarn into a tube and to freely distribute dyestuffs on to the knitted tube in order to impart various colours to the yarn. The tube is passed through rollers which press the tube flat and force differential migration of the dyestuff. The dyestuff is set, and the tube deknitted. However, the free distribution of the dyestuff on to the knitted textile yarn presents a severe limitation to the number of colours which may be applied to the yarn and prohibits precise control of the specific areas and location to which the colours are applied. The method is disclosed in U.S.A. Patent No.

4,828,405.

The prior art processes which space dye woven or knitted fabrics or space dye the individual yarns suffer from the disadvantage that not only are different printing rolls required for different colours but different printing rolls are required for different tones or shades of a particular colour. When a large number of colours and shades are required in a multicoloured yarn, the number of printing stations becomes large and the process becomes difficult to control and economically unattractive.

It is the object of the present invention to provide a method for producing space dyed yarn wherein two or more tones or shades of a colour can be applied to the yarn with one set of printing rolls.

According to the present invention there is provided a method for space dying a yarn which comprises: providing a prefabric from the yarn to be space dyed; providing two printing rolls to form a nip, wherein at least one of said printing rolls is provided with a relief pattern having at least two depths; filling the relief pattern with dye; passing the prefabric through the nip of the printing rolls to transfer dye from the relief pattern to the prefabric in at least two tones; and recovering the yarn.

The pair of printing rolls can each contain a matching relief pattern one of which is the mirror image of the other, having portions of the relief pattern in different depths, so that when the dye is transferred from the relief pattern to the prefabric, the colour is deposited in different tones or shades on the prefabric.

The tone or shade can further be controlled by registration of the matching patterns on the matching printing rolls. The deepest tones are produced when the relief patterns are in exact registration. When the relief patterns are slightly out of registration, the edges of the pattern show a gradation in tone.

The prefabric may be passed serially through two or more sets of printing rolls where multiple colours in at least two tones for each colour can be printed on the prefabric.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is a diagrammatic representation of a preferred embodiment of the invention; FIGURE 2 is a diagrammatic representation of straightening, padding, printing and dye setting operations according to an embodiment of the present invention; FIGURE 3 is a perspective view of two printing rolls having matching patterns; and FIGURE 4 illustrates the layout for the pattern of the two sets of matching printing rolls shown in Fig. 2.

As used herein, space dyeing refers to applying dye intermittently to a yarn or fabric. Coloured dyes may be applied intermittently to a fabric or yarn which has been dyed a solid colour and the dyes may be applied intermittently with some overlap of colours to provide an additional colour.

The dye can be applied intermittently to an undyed yarn or fabric and the fabric subsequently overdyed with a solid colour to provide a multicoloured yarn.

The process of the present invention can be utilized to prepare space dyed yarns prepared from continuous multifilament or staple yarns. Yarns can be prepared from synthetic or natural materials. Continuous multifilament or staple yarns prepared from nylon (polyamides), polyesters and acrylic polymers can be space dyed by the process of the present invention. The process of the present invention can also be applied to yarn prepared from natural materials such as for example cotton, wool and linen. The space dyed yarns prepared according to the method of the present invention can be utilized to prepare cloth, upholstery fabric, carpeting (particularly tufted carpeting) and knitted goods.

The space dyed yarn prepared according to the present invention overcomes the problem of streaking and provides colours in a multiplicity of tones or shades with a minimum of printing stations required for the process.

Figure 1 is a diagrammatic representation of a preferred embodiment of a complete process of the present invention.

The yarn which is to be space dyed is formed into a prefabric. The prefabric can be in the form of a knitted sock such as disclosed in U.S.A. Patent No. 3,701,315 or U.S.A. Patent No. 3,012,303, can be formed from a woven fabric such as disclosed in U.S.A. Patent No. 4,045,848 or can be in the form of parallel strands of yarn having a temporary entraining strand of yarn woven into an array of wraps as disclosed in U.S.A. Patent No.

3,908,247. Any cloth-like array is suitable for processing in the present invention. However, a prefabric in the form of a knitted tube or sock has been found to be particularly useful for space dyeing by the method of the present invention. A knitted flat cloth such as disclosed in U.S.A.

Patent No. 3,919,749 is also useful in the practice of the present invention. The prefabrics useful in the practice of the present invention are characterized in that they maintain the form of the prefabric as they proceed through the process but can be easily separated into the individual strands of yarn after the process has been completed.

Methods for fabricating prefabrics useful in the process of the present invention are well known in the art and will not be described further herein.

The prefabric is generally straightened to remove any wrinkles and kinks to insure that the fabric is lying flat so that it may be evenly dyed and printed in the process. When a knitted sock is utilized as the prefabric, the straightening and levelling of the knitted sock can be readily accomplished by the use of lease rods.

The prefabric can be dyed an overall solid background colour in a padding operation. The prefabric is contacted with the dye for a sufficient length of time for the fibers in the yarn to take up the required amount of dye to provide the background colour. The excess liquid from the dye bath is then separated from the prefabric and the prefabric is passed to the printing station.

It is preferred that the prefabric from the dyeing operation be damp when it is passed through the printing stations. The damp prefabric is more receptive to the dye applied from the printing rolls and the pattern can be applied in a more uniform manner.

The prefabric however need not first be dyed a solid background colour. The prefabric can be overdyed after printing, can be left as a white background or can be dyed after being incorporated into a finished article. The overall dyeing if used, may be incorporated into the process to suit the requirements of the equipment available and the finished product required by the operator.

The prefabric is then passed to the printing station where the prefabric is passed through the nip of at least one pair of printing rolls and preferably at least two pairs of printing rolls. The pairs of printing rolls have the desired intermittent pattern formed in relief on the face of at least one of the printing rolls. It is preferred that each pair of printing rolls have matching or mirror image patterns formed in relief thereon. In printing, the relief pattern on the printing roll is filled with dye, the excess dye removed from the outermost surface of.the printing roll by means of a device such as for example a doctor blade and the dye transferred to the prefabric as it passes through the nip of the printing rolls.The excess dye is removed from the outermost surface of the printing roll to ensure that the dye contained in the relief pattern on the printing roll is transferred to the prefabric as it passes through the nip of the printing rolls and not from the outermost surface of the rolls.

The intermittent relief pattern on the printing rolls is formed to different depths. The different depths of the relief pattern holding the dye provides varying amount of dye for transfer to the prefabric at the point where the pattern is brought adjacent to the prefabric at the nip of the rolls.

Where the relief pattern on the printed roll is deepest, the largest amount of dye is transferred to the adjacent portion of the prefabric. By varying the depth of the relief pattern, the dye can be transferred to the prefabric to form different tones or shades of a single colour on the prefabric. The penetration of the dye into the prefabric can be controlled by the depth of the relief pattern at a particular point, the pressure of the rolls and where the rolls have matching patterns, the registration of the pattern on the rolls.

When the rolls of one printing roll set have matching or mirror image patterns, registration of the patterns on the rolls increases the penetration of the colour. If the matching rolls are not in registration, the tone of the colour at the edges of the pattern will be of different tone or shade than the portion where registration occurs.

The relief pattern is formed of an intermittent pattern at two or more depths. A pattern having at least two different depths is necessary to provide at least two tones in the space-dyed printed pattern on the prefabric and yarn. Each portion of the relief pattern having a different depth provides colour deposited on the prefabric having a different tone or shade. The tone or shade of colour can also be modified by the combination of the colour of the dye printed on the prefabric and an overall background colour to which the prefabric has been previously dyed.

The relief pattern on the printing rolls can be in any random form for depositing areas or splotches of dye on the prefabric as it passes through the nip of the printing rolls. However, it has been found preferably to provide a pattern in the form of stripes which are printed on the prefabric at an angle to the longitudinal axis of the prefabric. An angle of from about 15 to about 400 with the longitudinal axis of the prefabric has been found to be suitable.

A flat layout of the pattern for two sets of printing rolls which print different colours in different tones or shades is shown in Fig, 4. Rolls 6 and 6' show a striped pattern at an angle of about 300 with the longitudinal axis of the prefabric. The pattern contains relief portions of two different depths noted by a and b. The relief portion area a is the shallowest portion of the pattern and would approximately correspond to a half tone printing plate. Area b is greater in depth than area a. Area b is the deeper relief portion of the pattern and would therefore transfer the largest portion of the dye to the prefabric and therefore provide the darkest tone or shade. The mating roll can be plain but preferably has a pattern which is the mirror image of the pattern on the roll with which it mates.

The pattern for the rolls 1 5 and 1 5' of the second printing station is also shown in Fig. 4. The pattern for the second printing station is in the form of stripes having relief areas d and e. Relief area d is the shallower depth; relief area e is the deeper relief portion of the pattern. The pattern is in the form of stripes at an angle of about 300 with the longitudinal axis of the prefabric. The 300 angle with the longitudinal axis of the prefabric is in the opposite direction from the angle at which the pattern on rolls 6 and 6' was formed. The patterns therefore cross each other on the printed prefabric the mating roll can be plain or have a pattern which is a matching pattern or a mirror image of the pattern on the roll with which it mates.

Since the stripes in the relief pattern on the two sets of printings rolls (6, 6' and 1 5, 1 5') are at different angles to the longitudinal axis of the prefabric, the stripes in the pattern when impressed on the prefabric cross each other. Since the patterns are of different colours, a third colour is introduced into the prefabric at the point where the patterns over print each other. By this method, a third colour can be printed on the prefabric by the use of only tvvo printing stations. In addition to the two or three colours introduced on to the prefabric, the three colours are in different tones or shades since the dye is transferred to the prefabric in different amounts due to the different depths of the relief pattern and the amount of dye which can be held therein.The depth of the relief pattern can vary from about 0.0005 inches (0.0127 mm) to about 0.070 inches (1.778 mm) to provide the various tones and shades of colour to the yarn in the prefabric. The depth of the relief pattern is also determined by the denier of the yarn and the tone required.

When the printing stations are disposed horizontally with one roll of a pair of printing rolls mounted above the other, it is advantageous to form the matching portions of the relief pattern in different depths on the top and bottom rolls to insure printing the same tone or shade on the bottom and top surfaces of the prefabric. Gravity aids in transferring the dye from the relief pattern on the upper roll to the prefabric and therefore the transfer of dye to the prefabric occurs at a faster rate than from the relief pattern on the lower roll.

The relief pattern in the upper roll can therefore be formed to a slightly shallower depth than the matching relief pattern in the lower roll to obtain substantially the same tone transferred to the fabric. As an example, if the deep relief pattern in the upper roll has a depth of 0.016 inches (0.4064 mm) the depth of the matching pattern in the lower roll should be about 0.018 inches (0.4572 mm) to insure transfer of a pattern of equal shade or tone to the prefabric. Likewise, if the relief pattern in the upper roll has a depth of 0.004 inches (0.1016 mm) the depth of the pattern in the lower roll should be about 0.005 inches (0.127 mm) to insure that the tone or shade of the colour transferred to the prefabric is about the same on both surfaces.This novel aspect of the invention is useful when the printing stations are disposed horizontally with one of the matched pair of printing rolls disposed above the other. If the printing stations are disposed vertically with the matching printing rolls disposed side by side, the depth of the matching portions of the relief patterns should be the same.

The pressure applied to the printing rolls at the nip can be varied to modify the penetration of the dye into the prefabric. In addition, the shade and/or tone of the pattern deposited on the prefabric can be varied to some extent by modifying the registration of the matching patterns on the printing rolls. The deepest tone or darkest shades are obtained when the matching patterns are in perfect registration. When the matching patterns are not in perfect registration, the edges of the patterns become blurred and the tone or shade of the colour changes. The gradation of tone or shade can provide a pleasing effect to the yarn produced by the present process.

Although the printing rolls shown have a striped pattern which prints in different directions for the different printing stations or colours, other forms of intermittent patterns can be utilized in the present process. Irregular shapes, geometric forms, crosses, stars, random splotches, amoeba like forms, donut like profiles and the like may be utilized as the relief pattern on the printing rolls. A striped pattern can be engraved on two or more sets of printing rolls at the same angle so that the coloured stripes on one set of printing rolls are printed in the vacant space between the stripes on another set of printing rolls.

The patterns can be varied by a combination of geometric or irregular figures to provide intermittently coloured yarns and prefabrics with interesting visual appearances. The patterns in two or more printing stations can be arranged so that portions of the patterns print over each other to form additional intermittent colour in the prefabric and the yarn produced by the process.

The prefabric leaving the printing stations proceeds to a means for setting the dye in the yarn. The dye is usually set by confining the prefabric in a heated zone where the prefabric is heated by steam or dry gases. In the heating zone, the dye is set and any loops or crimps imparted to the yarn in making the prefabric can be partially set in the yarn.

After the dye is set, the prefabric is passed through a scouring and drying zone wherein the prefabric is washed and dried. in the washing or scouring zone, the prefabric is contacted with water or some other solvent to remove the dye materials which have not been set in the prefabric.

In addition, conditioning agents can be imparted to the prefabric to improve the hand, lubricity or other properties of the yarn.

The washed and dried prefabric is then passed to a zone wherein the yarn is recovered and wound on for example bobbins or spools. If the prefabric has been knitted in the form of a tube or sock, the prefabric is unravelled to recover the yarn and the yarn is wound on a supporting means which can be transferred to a process in which the yarn is utilized. If the prefabric is of a woven type, the weft is removed and individual warp yarns recovered on a windup means and support.

The yarn prepared according to the process of the present invention has imparted thereto colours in a random intermittent pattern wherein each colour is present in at least two shades or tones on the yarn.

Figure 2 is a diagrammatic representation showing some of the major operations which canbe combined with the multiple tone printing rolls to provide the intermittently dyed multicoloured space dyed yarn of the present invention.

As shown in Fig. 2, prefabric 1 which can be in the form of a woven cloth, a knitted cloth or tube is straightened by passing over lease rods 2 wherein wrinkles or kinks in the prefabric are removed. The straightened and level prefabric passes into padding bath 4 and proceeds through the bath over rollers of rods 3 in a tortuous path.

The tortuous path provides a sufficient residence time of the prefabric in the dye bath to provide the colour required. The overall solid background colour imparted to the yarn and prefabric in the padding bath can be controlled by adjusting the concentration of dye in the padding bath and the length of time which the yarn or prefabric is in contact with the dye solution in the bath. The prefabric 1 passes between the nip of padding rollers 5 wherein the excess dye is moved from the prefabric.

The wet prefabric then proceeds to printing station 30 where it passes between the nip of printing rolls 6 and 6' and 1 5 and 15'. Printing rolls 6 and 6' have matching intermittent patterns in relief on their surface. Relief patterns can be formed by known means such as for example engraving and rotogravure. It is essential however that relief patterns be formed at at least two different depths on the rolls. Since the rolls as shown in printing station 30 are on a horizontal stand, to ensure even colour tones and hues on both sides of the prefabric, the matching portions of the pattern in the lower roll 6' should be slightly deeper than the equivalent portion of the matching pattern in upper roll 6.The slight differences in depth of the relief pattern is necessary to ensure even tones from the upper printing roll and the lower printing roll since the flow of dye from the upper printing roll is assisted by the effects of gravity and therefore permeates the prefabric at a faster rate than the dye held in the relief pattern on the lower roll.

The upper printing roll 6 is supplied with dye from dye trough 7. The excess ink from the surface of printing roll 6 is removed by doctor blade 8 which is a part of dye trough 7. The doctor blade 8 removes the dye from the surface of printing roll 6 and leaves the relief portions of the pattern filled with dye. Lower printing roll 6' rotates in a pool of dye contained in a dye trough 10. The excess dye is removed from the surface of the printing roll by doctor blade 9. As the prefabric 1 passes between the nips of printing rolls 6 and 6', the dye contained in the intermittent relief patterns on the rolls is transferred to the prefabric. The dye penetration of the fabric can be adjusted by adjusting the pressure applied to the prefabric at the nip of the printing rolls.

If only one of the printing rolls 6 and 6' has the relief pattern of different depths, then only one dye supply would be required and only one doctor blade would be needed.

The prefabric 1 which has passed through the nip of printing rolls 6 and 6' has printed thereon an intermittent colour pattern having different tones of the colour which was applied at the nip between the printing rolls. The prefabric then passes to the nip between printing rolls 1 5 and 15'. At the nip between printing rolls 1 5 and 1 5', a second colour in two or more shades or tones is applied to the prefabric in an intermittent pattern.

Dye is supplied to printing roll 15 from dye trough 11 and excess dye is removed from the surface of the printing roll by doctor blade 12 which is a part of dye trough 11.

Lower printing roll 15' rotates in a pool of dye in dye trought 14. The excess dye is removed from the surface of printing roll 15' by means of doctor blade 13. The surface of the roll is wiped substantially clean of dye and the dye is carried to the prefabric in the relief pattern formed on the printing rolls.

The matching pattern in roll 15' is of a slightly deeper depth than the relief pattern in roll 1 5 since the flow of dye from the relief pattern on the upper printing roll is assisted by the forces of gravity. The flow of dye from the relief pattern in roll 1 5' is retarded by the forces of gravity and therefore more dye is supplied to the lower roll than to the upper printing roll.

The prefabric 1 then passes from printing station 30 to dye setting zone 1 6. Dye setting zone 16 is a chamber in which the prefabric is raised to an elevated temperature to set the dye and to partially set any crimps or loops which have been formed in the yarn. The prefabric enters the dye setting zone 1 6 through inlet 20, passes through the dye setting zone in a tortuous path over rollers 1 7. The tortuous path provides a sufficient amount of residence time for the prefabric to reach the temperature of the gases in the dye setting zone and to permit the dye to set.

Heated gases are admitted into the dye setting zone through inlet means 18 and are removed through outlet means 1 9 to provide a flow of super heated steam or hot gases through the dye setting zone.

The dyed prefabric leaves the dye setting zone through outlet means 21 and pass to a scouring, drying, unravelling and windup means to form the multicoloured intermittently dyed yarn which is useful for forming, for example fabrics, carpets and knitted goods. The straightening, dyeing, dye setting, scouring, drying unravelling and windup means are not discussed in detail herein since they are well known in the art and form no critical portion of the present invention.

The present invention is the novel and more obvious configuration of the printing rolls which permits the intermittent dyeing of the yarn in two or more shades or tones of the same colour by one set of printing rolls. The conformation and configuration of the printing rolls is extremely useful since the number of printing stations in a printing stand can be substantially reduced when forming the multicoloured intermittently dyed yarn of the present invention.

Figure 3 is a view in perspective of the essential features of the configuration of printing rolls 6 and 6' in printing station 30. The essential features of the printing rolls 6 and 6' are shown without regard to supporting structure or means for rotating the rolls or means to transport the prefabric between the nip of the rolls. Fabric printing machines are well known in the art and the supporting structure and operating means for the printing machine will not be discussed in detail herein since the present invention is more concerned with the form of the pattern carried by the printing rolls rather than any structure or operating means which aid them in carrying out their function.

Printing rolls 6 and 6' carry an intermittent relief pattern on the rolls. As shown in Fig. 3, the relief pattern is formed as stripes in two depths which provide two different tones or shades to the colour deposited on the prefabric 1. The relief pattern can be formed by engraving or other means known in the art for forming relief patterns on printing rolls.

In operation, the dye is deposited in relief patterns a and b on roll 6 from dye trough 7. The dye is removed from the surface 25 of printing roll 6 by means of doctor blade 8 shown as a part of dye trough 7. Doctor blade 8 can be a means separate from dye trough 7 but must perform the function of removing the excess ink from the surface 25 of printing roll 6. Printing roll 6' revolves in a pool of dye present in dye trough 10.

The dye is deposited in the intermittent relief patterns a and b of roll 6' and the excess dye is wiped from the surface 25 of printing roll 6' by doctor blade means 9. A doctor blade is shown in Fig. 3 but other means for effectively removing the excess dye from the surface of printing roll 6' may be utilized. Means for supplying dye to a relief pattern on a printing roll and removing the excess dye from the surface of the printing roll are well known in the art and means other than those shown can be effectively employed in the process tf the present invention.

As shown in Fig. 3, printing rolls 6 and 6' have matching random patterns and contact the prefabric 1 in registration to provide the intermittent colour in sharp registration on-the prefabric. The printing rolls 6 and 6' can be out of register to some degree and provide additional tones at the edges of the relief patterns on the prefabric. By providing a small degree of misregister of the printing rolls which should not exceed about 5 degrees, an interesting and visually pleasing effect can be imparted to the yarn.

As shown in Fig. 3 rolls 6 and 6' have matching relief patterns on their surface. However, the multiple tone effects can be achieved if only one roll that is either 6 or 6' has the relief pattern of different depth. However, it is preferred that the printing rolls have matching relief patterns of varying depth. The depth of the relief pattern on bottom printing roll 6' should be from about 2% to about 35% deeper than the matching portion of the relief pattern in upper roll 6. The difference in the depth of the relief pattern provides for more even tones to the pattern imprinted on the prefabric. However, if the printing rolls are in a vertical stand where the rolls are side by side the depth of the relief pattern in each roll should be the same.

It is clear that more than two tones or shades of a colour can be space-dyed on a prefabric or yarn by providing printing rolls having a relief pattern with more than two different depths.

The dyes utilized in the process of the present invention are well known in the art of printing colours in fabrics and yarns and need not be described in detail herein. The dyes correspond to the colours required and should have physical properties which permit them to be retained in the relief pattern on the roll and to be readily transferred to the prefabric.

The invention has been set forth in sufficient detail for one skilled in the art to practice the invention. However many modifications of a minor nature can be utilized without affecting the novel use of the printing rolls having the relief patterns of different depths thereon. The relief patterns can be provided by engraving or other means known to those skilled in the art.

Claims (9)

1. A method for space dyeing a yarn which comprises: providing a prefabric from the yarn to be space dyed; providing two printing rolls to form a nip, wherein at least one of said printing rolls is provided with a relief pattern having at least two depths; filling the relief pattern with dye; passing the prefabric through the nip of the printing rolls to transfer dye from the relief pattern to the prefabric in at least two tones; and recovering the yarn.

2. A method according to claim 1 wherein the two printing rolls have matching relief patterns.

3. A method according to claim 1 or 2 wherein the depths of the matching relief patterns in the two printing rolls are different.

4. A method according to any one of the preceding claims, wherein the prefabric is serially passed through the nip of at least two sets of printing rolls whereby at least two colours are space dyed on the prefabric.

5. A method according to any one of the preceding claims, wherein at least one of said sets of printing rolls has matching patterns which are in registration.

6. A method according to any one of the preceding claims, wherein at least one of said sets of printing rolls has matching patterns which are in registration.

7. A method according to any one of the preceding claims which comprises: preparing a prefabric from the yarn to be space dyed; passing the prefabric through a dyeing zone containing an aqueous dyeing medium to provide a prefabric with a solid background colour; passing the wet prefabric through the nips of the printing rolls to transfer dye from the relief pattern to the prefabric in at least two tones by each set of rolls; setting the dye; scouring and drying the prefabric; and unravelling the prefabric and winding the yarn on a support means.

8. A method according to any of the preceding claims wherein the prefabric is in the form of a knitted sock.

9. A method for space dyeing a yarn substantially as described herein and as illustrated in Figure 1 with or without reference to Figures 2 to 4 of the accompanying drawings.

1 0. A space dyed yarn whenever prepared by a method according to any one of the preceding claims.