CONTROLLED APPLICATION OF LIQUID TO YARN

Abstract: A method of applying liquid to a travelling yarn (11) includes providing for the yarn (11) to be intermittently relatively moved transversely of its direction of travel into and out of a liquid application zone (15), and maintaining a flow of liquid through the zone. Liquid is thereby taken up by the yarn (11) when the latter is in the zone (15) and is thus applied intermittently along the length of yarn. The flow of liquid through the application zone is laterally confined (31) with respect to the direction of travel of the yarn, and the liquid is delivered (32) as a stream from a reservoir (33) to the application zone (15) in a manner whereby integrity of the stream is sustained at yarn speeds greater than 100m/min. Corresponding apparatus is also disclosed.

Description: "CONTROLLED APPLICATION OF LIQUID TO YARN" This invention relates to the controlled application of liquid to a travelling yarn, and as such may be employed in space dyeing or in the application to yarns of polymers, setting agents or dye substantivity modifiers. In the manufacture of textile products, special aesthetic effects can be achieved if the yarn used is coloured in different sections along its length with different colours or different shades of the same colour. The sequence of the colour bands may be to a specific pattern or may be random. Such yarn is known as being 'space dyed' and has been manufactured previously at high cost either because of the use of expensive equipment or because the methods employed are labour intensive. For convenience the invention will be primarily described herein in relation to space dyeing, but it is to be emphasized that this in no way implies a limitation on the scope of application of the invention. Methods of applying fluid to yarn in a non-uniform manner, in particular dye liquor so as to produce multicoloured or space dyed effects, include the following: (1) A method such as disclosed in United States Patent 4, 184,348 in which hanks of yarn are partially immersed 5 in one dyebath and then another section of the hank is immersed in a second dyebath of a different colour. (2) A method such as disclosed in United States Patent 4,329,143 in which the yarn is first knitted into Q fabric, dye is applied to the fabric in a random manner, then fixed and washed off and finally the yarn is unravelled from the knitted fabric as product from the process. *L5 (3) A method such as disclosed in United States Patent 4,027,271 in which yarn is deflected into and out of the nip area of a pair of rollers to which dye is applied. (4) A method such as disclosed in British " Patent 1, 20 313,764 in which yarn is brought into contact with a lick roller by means of a second roller which is caused to oscillate. The lick roller is partially immersed in a dye liquor. 25 (5) A method such as disclosed in United States Patent 4,153,961 in which yarn being wound onto hanks passes beneath oscillating dye nozzles. (6) A method such as disclosed in British Patent 30 1,552,020 in which dye pulses are applied to yarns from spray nozzles, the supply of dye to which is interrupted by means of electromechanical valves. (7) A method such as disclosed in British Patent 1,374,668 in which intermittent dye pulses are applied to a preheated moving yarn as it passes through one or more application grooves. Dye is delivered to the groove along a duct opening into the groove and is pulsed by solenoid valves or the like. (8) A method such as disclosed in British Patent 1,228,664 in which yarn is spaced dyed by injecting liquors containing reactive dyes into preformed yarn packages. (9) A method such as disclosed in British patent 1,229,855 in which revolving bars are alternately dipped into a liquid bath and brought into contact with the travelling yarn. (10) method such as disclosed in U.S. patent 3,813,902 in which multiple travelling yarns contact liquid flowing over the shoulder of an adjustable plate. Liquid is delivered to the plate by a conventional lick roller. Methods involving dipping of hanks into dye liquors have the disadvantages that it is not possible to dye short lengths of yarn, that truly random dyed yarn cannot be produced, and that the cost of labour involved in the production is unacceptably high. Method (2) is time consuming and entails a high labour cost. In addition, the mechanical action of knitting/deknitting causes irregularities in the product yarn. Methods (3) and (4) are only suited to yarns of a high tensile strength as yarn breakage can easily occur when the yarn is mechanically moved into and out of the dye roller nip or into and out of contact with the lick roller. Yarn flattening and distortion is likely in the nip configuration. A further disadvantage of method (4) is that dyeing becomes non-uniform over a period of time as contaminants from the yarn concentrate in the dye bath in which the lick roller is immersed, causing changes in shade. A general disadvantage of methods which rely on devices such as lick rollers, revolving bars and engraved or embossed rollers, and this includes method (9) and the indirect delivery technique of method (10) , is the inevitably low operating speeds required if liquid throw-off is to be avoided. Throw-off entails loss of liquid, a messy environment (which may be most undesirable in multiple yarn machinery) , and inability to properly control the fluid quantity in the application zone. It will be appreciated that the surface speed of the roller or other element carrying the liquid must generally correspond to the forward speed of the yarn. It is thought that throw-off will occur at surface speeds, and therefore yarn speeds, between 10 and 50m/min, depending on the particular configuration used and the viscosity of the liquid, but modern commercial winders are capable of yarn speeds up to 3000m/min. Another general feature of lick rollers and like configurations is the practice of delivering liquid to the application zone at a rate far in excess of the rate at which liquid is being taken up by the roller. This alone precludes fine controlled application of the liquid. Because of dye spatter, method (5) can also only be operated at low speeds and further processing is expensive because the handling of hanks is labour intensive. Dye spatter is also a problem with method (6) , which with method (7) suffers the further disadvantages that the reproducibility of the pattern is poor and that the slow response times of the valves preclude the application of short printed lengths at high speeds.. Method (7) requires the yarn to be preheated and, in common with all methods in which the flow of dye is interrupted, the evenness of dyeing along the yarn varies because of liquid surging. With method (8) , it is not possible to produce short pattern lengths and there is also a lack of reproducibility because the depth of shades produced depends so much on the density of the yarn packages being treated. Prior methods as described above therefore either tend to require expensive and complicated machinery or are expensive because of low production rates or high labour requirements. It is accordingly an objective of the invention to provide a method and apparatus by which the controlled application of the liquid may be achieved at high yarn speeds. The invention provides a method of applying liquid to a travelling yarn, comprising providing for the yarn to be intermittently relatively moved transversely of its direction of travel into and out of a liquid application zone, and maintaining a flow of liquid through the zone, whereby the liquid is taken up by the yarn when the latter is in the zone and is thus applied intermittently along the length of the yarn, characterized in that said flow of liquid through the application zone is laterally confined with respect to the direction of travel of the yarn, and in that said liquid is delivered as a stream from a reservoir to said application zone in a manner whereby integrity of the stream is sustained at yarn speeds greater than lOO /min, and preferably at a volume rate which, when the yarn is in the application zone, is no more than 50% greater than the rate at which liquid is being taken up by the yarn. The invention also provides apparatus for applying liquid to a travelling yarn, comprising: means defining a liquid application zone; reservoir for the liquid; means to deliver liquid from the reservoir to said application zone and to maintain a flow of the liquid through said zone; means to cause the yarn to intermittently relatively move transversely of its direction of travel into and out of said liquid application zone; characterized in that: said defining means includes structure for, relative to the direction of travel of the yarn, laterally confining said flow of liquid through the application zone, and in that said delivery means is arranged to deliver the liquid as a stream in a manner whereby the integrity of the stream is sustained at yarn speeds greater than lOOm/min. In accordance with the invention, there is still further provided apparatus for applying liquid to a travelling yarn, comprising: means defining a fluid application zone; and means to cause the yarn to intermittently 0 relatively move transversely of its direction of travel into and out of said liquid application zone; characterized in that said means to intermittently move the yarn comprises directly driven reciprocable abutment means to intermittently move the yarn away from ■, c a natural position in said application zone, which abutment means comprises a rotatable plate with a projecting pin disposed for engagement with the yarn at the side surface of the pin when the plate rotates in one direction. 20 The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagramatic perspective view of duplex apparatus according to the invention for applying two different liquids to a travelling yarn; Figure 2A is a longitudinal central cross-section of one of the fluid applicators shown in Figure 1; Figure 2B is an end elevation on the line 2B-2B in Figure 2A; Figure 3 is a schematic side view of a yarn treatment arrangement incorporating the apparatus of Figure 1, which arrangement might be used for space dyeing, for the random application of a dye substantivity modifier, or for the random application of a fluid containing the components necessary for polymer treatment; Figure 4 is a partly sectioned isometric view of an alternative, more compact, embodiment of apparatus according to the invention; Figure 4A separately depicts the fluid distribution form which is a component of the apparatus depicted in Figure 4; Figure 5 is a schematic side view of an alternative yarn treatment arrangement incorporating the apparatus shown in Figure 4; Figure 6 is an isometric diagrammatic view of a further embodiment of apparatus according to the invention; and Figure 7 sets out sequences of steps for various processes in which the method of the invention may be used. The apparatus 10 of Figures 1, 2 and 2A includes a yarn tensioning device 12 for a travelling yarn 11, a pair of substantially identical fluid applicators 14, 14' defining liquid application zones 15, 15', means 16 for causing yarn 17 to intermittently move transversely of its direction of travel into and out of the liquid application zones 15, 15*, and an intersecting fluid distribution form 18 with co-operating guide pins 19, 19a. In use, yarn 11 is drawn continuously past the various components, by a winder or like device not shown in Figure 1. Means 16 comprises reciprocable abutment means in the form of a pair of pins 20, 21 arranged to opposite sides of the yarn and fixed to a plate or cross-arm 22 mounted for rotation with the drive shaft 24 of an electric stepper motor 26. Cross-arm 22, and accordingly pins 20, 21, are oscillatable by motor 26 in accordance with a predetermined fluid application program. This program may be stored in ROM in a microprocessor 28 which controls the motor. It- is to be noted that in its natural position determined by tensioning device 12 and other guide elements such as form 18, yarn 11 lies in the liquid application zones 15, 15' and is intermittently moved out by the action of the respective reciprocable pins 20, 21. The detailed configuration of fluid applicators 14, 14' is shown in Figures 2A and 2B. Each applicator comprises a solid block 30 with a forward V-section recess 31, the inner portion of which defines the fluid application zone 15, 15'. It will be observed that the zone is bounded by a stationary surface and is laterally confined with respect to the direction of travel of the yarn. During operation, liquid is continuously delivered from a reservoir 33 via a metering pump and associated flow control device 33a and a small tube 32 which opens in the upper end of the floor of recess 31. The use of a tube 32 rather than a lick roller system or the like allows liquid delivery rates corresponding to yarn speeds well in excess of lOOm/min and certainly up to present commercial winder speeds of 3000m/min. Excess fluid may be recovered from the zone for recycling or disposal by an optional suction tube 34 which opens at the lower end of the zone. In use of the apparatus, fluid, for example dye liquor of different colours, is continuously fed to each liquid application zone 15 at a steady ' rate controlled by device 33a such that there is no jetting from the mouth of tube 32 but so as to maintain a continuous flow of the fluid in a film which flows along the surface defining zone 15 to suction tube 34. Pins 20, 21 are reciprocated to intermittently move the yarn transversely of its direction of travel out of the zones 15, 15' respectively. The respective liquid is taken up by the yarn when the latter is in each zone and is thus applied intermittently along the length of the yarn. Because the films in the zones flow as a continuous film with no jetting from the mouth of tube 32, this transverse movement of the yarns at the applicators 14, 14' can be a little as 1 mm. For optimum control and to minimise the presence of excess liquid, the volume rate of delivery of liquid to each zone 15, 15' when the yarn is in the zone is no more than 50%, preferably no more than 10%, greater than the volume rate at which liquid is being taken up by the yarn. At a rate above 50%, the yarn itself tends to cause spatter and there is loss of desired control. In most cases, the volume rate of delivery is also at least equal to the volume rate at which liquid is being taken up by the yarn, but a lower rate may be employed to obtain special effects. Most preferably, the liquid is delivered to the application zone at a volume rate which, when the yarn is in the application zone, is substantially equal to the volume rate at which liquid is being taken up by the yarn. The rate thus selected will depend of course on yarn speed and on the nature of both the yarn and the liquid, and will necessarily be determined by empirical techniques for a given application. Pins 20, 21 form a secondary role in providing surfaces to facilitate the distribution of the liquid in and/or along the yarn. Intersecting distribution form 18, in co-operation with pins 19, 19a, further assists to this end: it is preferable that the position of form 18 with respect to pins 19, 19a is adjustable in order that, for different yarns, the optimum amount of liquid distribution can be effected without significantly affecting yarn tension. It is preferred but not essential that applicator blocks 30, 30', pins 20, 21, 19, 19a and form 18 are constructed from or contain a hard wearing material such as a ceramic. It is found, surprisingly, that when the motor shaft is restored to its position corresponding to yarn contact with the fluid film in one or both application zones 15, 15', the yarn also rapidly returns into contact with the fluid if the yarn velocity is in excess of 48 metres per minute. For lower velocities, although the invention may still be employed, the rate of return may not be as rapid as might be desirable to ensure an accurate response in accordance with a preprogrammed pattern. Figure 3 schematically depicts a practical arrangement in which the apparatus of Figure 1 might be incorporated. Yarn 11 is drawn continuously from a package 40 through a tensioner 12 and a pair of applicators 14, 14'. In this case, in its centre position, the yarn travels through the liquid films in the fluid application zones of the applicators. Contact between the yarn and the fluid application zones is interrupted by means of stepper motor 26 which is controlled by means of microprocessor 28 and its associated electronics. The path of the treated yarn is changed by means of free-running pulleys 42 or yarn guides, for optimum presentation to a winder 44. This . configuration may be conveniently employed for space dyeing, for the random application of a dye substantivity modifier, or for the random application of components necessary for polymer treatment, for example a polymer pre-cursor and a gaseous catalyst. More compact apparatus 10' ' in accordance with the invention is depicted as a second embodiment thereof in Figures 4 and 4A, in which like parts are indicated by like reference numerals. In this case, the liquid applicator 14'* is similar to the applicator 14 of Figure 1, but the yarn moving means 16' ' instead includes a solid form 17 which seats in and complements the V-recess of the applicator, with respect to which it is pivotable about a transverse axis by means of a pair • of pins 50 on the form that seat in complementary grooves 51 on the upper surface of block 30' '. The actual fluid application zone 15'' is inclined and the adjacent edge 17a of pivotable form 17 also acts as a distribution aid. A small hook element 19'' on the underside of the form serves as the means for actually engaging and transversely moving the yarn: to this end, form 17 is pivotably oscillated according to a predetermined program in a manner similar to the control of stepper motor 16 in the embodiment of Figure 1. The pivoted arrangement of form 17 is also useful in allowing knots, such as that indicated at 60 in Figure 4, to clear the apparatus without resulting in breakage of the yarn. It may be advantageous for the section of form 17 which is in contact with the yarn to have one or more convolutions to aid in fluid distribution. An arrangement utilizing the apparatus of Figures 4 and 4A is schematically depicted in Figure 5. Yarn 11 f ' is drawn from a package 40' ' through a tensioner at 12'', applicator apparatus 10" and a yarn steamer 46 to a winder 44''. Form 17 is oscillated in this case by a solenoid 48 which is in turn controlled by a microprocessor and associated electronics 28'*. Figure 6 shows a further embodiment of the invention whereby a moving yarn is " intermittently moved transversely of its direction of travel into and out of a fluid application zone. There, fluid is fed to each fluid application zone 15' ' ' at a rate such that jetting occurs from the mouth of a respective tube 32' ** which thereby acts a jet nozzle and acts to confine the jetted stream laterally with respect to the direction of yarn travel. The stream may be broken into droplets if desired. Pins 20 1 '*, 21''' are oscillated to move the yarn transversely out of its direction of travel into and out of the zones 15'*', 15' 1 '. A suction device, 34''', may be used to collect the fluid when the yarn is not in contact with the droplet stream. It will be appreciated that the microprocessor used to control, for example, the stepper motor of the first embodiment or the pivotable form of the second, may be programmed to result in a discernible pattern of liquid application or may be provided with, say, a random number selection routine so that an entirely random effect can be obtained in the yarn. It is not possible with many prior methods to obtain an assumed indefinite random effect. It is a feature of the present invention that, ' while one applicator only may be employed, a multiplicity of applicators may be incorporated in order that a number of different fluids may be applied to each yarn. This is of particular use in space dyeing to achieve multicoloured effects. The invention is not limited to applicators which only have one fluid feed tube per applicator as in some cases it is desirable to feed two or more fluids to a yarn at the same time (for example if the fluids are unstable when premixed prior to application) . It may also be of advantage to treat the yarn with a liquid using one applicator and with a gas using a second applicator (for example a polymer precursor may be applied using the first applicator and a gaseous catalyst using the second) . Furthermore a number of yarns may be treated simultaneously by installing a number of treatment units in parallel if so desired. Various treatment sequences are set out, by way of example, in Figure 7. " It is a further feature of the present invention that fluids may be metered onto the yarn at liquid pick-ups in the range 1 to 50% (per cent weight of fluid absorbed per unit weight of yarn in the treated area) , which is much lower than by previously known methods. This feature has economic advantages in that less energy is required in drying the treated yarn than for the existing methods. By virtue of the inventive method, a high degree of evenness of liquid application can be achieved. Because the fluid is metered to the applicators in a controlled continuous manner whereby the excess of liquid is no more than 50% when the yarn is in contact with the liquid, and because it is the moving yarn which is brought into and out of contact with the fluid, the linear distribution of fluid is very uniform. This is in contrast, for example, to those methods which have been cited above which use electromechanical means to interrupt the flow of dye as a means of achieving space dyed effects. In such methods surging (and hence uneven application) occurs at the start of each dye pulse and wicking may occur to give rise to an unwanted streak of colour after each dye pulse. It has also been found that the radial distribution of fluid can be made very uniform, even when using a single fluid application, by the use of distribution forms such as 18, 17. Even radial distribution has not been possible to such an extent with any prior method. Both of the illustrated embodiments allow the passage of knots through the apparatus without breaking the yarn being processed, a feature which is most important for the efficient operation of yarn handling equipment. A further feature of the illustrated embodiments is that fluid may be recycled by means of the suction tubes when yarn is not in contact with the •fluid applicators. This feature has a secondary advantage in minimising fluid spatter, a disadvantage of some previous methods. The yarns which may be treated by the methods of the present invention are not limited in their type and may include yarns spun from staple fibres, continuous filament yarns, or textured or crimped yarns, and may be of single or multiple ply. The yarns may be composed, e.g. of natural fibres such as wool, silk, cotton, flax or mohair or of synthetic fibres composed of polyamides, polyesters, acrylics, polyolefins, man-made cellulosics (e.g. viscose rayon, cellulose acetate) , glass fibre or blends thereof. When the apparatus according to the invention is used for the application of dyes or pigments to yarn in a controlled manner, those agents and their formulations can be chosen according to their suitability for the fibres to be coloured. If desired, a swelling agent for the fibres, carrier, thickener, solvent, surface active agent, polymer precursor, levelling agent, or one or more of the other components known to those skilled in the art, may be added to the dye or pigment in order to achieve the objectives of the invention more effectively. The invention is not limited.to any dye fixation method or dyestuff combination or any post-treatment required in the treatment of the yarn such as drying', steaming, felting or any other methods known to those skilled in the art. 17 Example A white worsted spun pure wool yarn (R75 tex, 2 ply) was passed at a velocity of 385 m/min through an apparatus as shown in Figure 1. A dye liquor of composition according to Formulation A was fed to the upper applicator and a dye liquor of composition according to Formulation B was fed to the lower applicator. The total liquid feed rate was equal to 30% of the yarn feed by weight. The microprocessor was so programmed that the yarn was caused to contact the liquid in the application zone for short intervals of time in a random manner. The length of the individual coloured sections of the yarns ranged from 20 to 40mm. Each colour was sharply defined and was consistent in area, shade and depth around and along the length of the yarn. One package of the space-dyed yarn was knitted into an outerwear garment. The attractive three-colour effect was uniform throughout the complete garment. DYE FORMULATION A & B AMOUNT (parts by weight) C.I. REACTIVE RED 84 25 (FORMULATION A) C.I. REACTIVE BLUE 69 25 (FORMULATION B) UREA . 400 LACTIC ACID (88%) 10 SOD, DI-ISO-OCTYL SULPHOSUCCINATE 1.5 LAMEPRINT 651 (GRUNAU) 2 MATEXIL PNVP (ICI) 10 WATER 600

Claims: CLAIMS : 1. A method of applying liquid to a travelling yarn, comprising providing for the yarn to be intermittently relatively moved transversely of its direction of travel into and out of a liquid application zone, and maintaining a flow of liquid through the zone, whereby the liquid is taken up by the yarn when the latter is in the zone and is thus applied intermittently along the length of the yarn, characterized in that said flow of liquid through the application zone is laterally confined with respect to the direction of travel of the yarn, and in that said liquid is delivered as a stream from a reservoir to said application zone in a manner whereby integrity of the stream is sustained at yarn speeds greater than lOOm/min. 2. A method according to claim 1 further characterized in that said liquid is delivered to said application zone at a volume rate which, when the yarn is in the application zone, is no more than 50% greater than the volume rate at which liquid is being taken up by the yarn. 3. A method according to claim 1 or 2 further characterized in that said flow of liquid is maintained in said application zone along a surface which remains substantially stationary. 4. A method according to claim 3 further characterized in that said flow of liquid is a continuous film on said surface which moves substantially parallel to the direction of travel of the yarn. 5. A method according to claim 3 or 4 further characterized in that the liquid is delivered to the application zone along duct means opening in said surface. 6. A method according to any preceding claim further characterized in that said liquid is delivered to the application zone at a volume rate which, when the yarn is in the application zone, is substantially equal to the volume rate at which liquid is being taken up by the yarn. 7. A method according to any preceding claim further characterized in that said application zone is stationary and the yarn intermittently moves into and out of the application zone. 8. A method according to claim 7 further characterized in that the yarn is in the application zone in its natural position and is intermittently moved out of the zone by directly driven reciprocating abutment means. 9. A method according to any preceding claim further characterized by bringing the travelling yarn, after it has traversed said application zone, into temporary contact with form means to facilitate distribution of the liquid in or along the yarn. 10. Apparatus for applying liquid to a travelling yarn, comprising: means defining a liquid application zone; a reservoir for the liquid; means to deliver liquid from the reservoir to said application zone and to maintain a flow of the liquid through said zone; and means to cause the yarn to intermittently relatively move transversely of its direction of travel into and out of said liquid application zone; characterized in that: said defining means includes structure for, relative to the direction of travel of the yarn, laterally confining said flow of liquid through the application zone, and in that said delivery means is arranged to deliver the liquid as a stream in a manner whereby the integrity of the stream is sustained at yarn speeds greater than lOOm/min. 11. Apparatus according to claim 10 further characterized in that the application zone is defined by a surface which remains substantially stationary. 12. Apparatus according to claim 11 further characterized in that said delivery means includes duct means opening in said surface. .13. Apparatus according to claim 10, 11 or 12 further characterized in that said means to cause the yarn to intermittently relatively move comprises means to intermittently move the yarn away from a natural position in said application zone. 14. Apparatus according to claim 13 further characterized in that said means to intermittently move the yarn comprises directly driven reciprocable abutment means. 15. Apparatus according to any one of claims 10 to 14 further characterized by form means downstream of said application zone, for facilitating distribution of the liquid in or along the yarn. 16. Apparatus for applying liquid to a travelling yarn, comprising: means defining a fluid application zone; and means to cause the yarn to intermittently relatively move transversely of its direction of travel into and out of said liquid application zone; characterized in that said means to intermittently move the yarn comprises directly driven reciprocable abutment means to intermittently move the yarn away from a natural position in said application zone, which abutment means comprises a rotatable plate with a projecting pin disposed for engagement with the yarn at the side surface of the pin when the plate rotates in one direction.

Inventors: MIHAJLOVIC STEVEN VINCENT, PEARSON ANTHONY JOHN CRAWFORD, WHITE MAXWELL ALEXANDER, MIHAJLOVIC, STEVEN, VINCENT, PEARSON, ANTHONY, JOHN, CRAWFORD, WHITE, MAXWELL, ALEXANDER
Applicants: COMMW SCIENT IND RES ORG, COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH OR
Application year: 1985
Main classification: D06B11
IPC codes: D06B11