PT93410A - Device and process for spray dyeing movable substrates - Google Patents

Abstract

Process and device for dyeing a substrate using a set of sprayers. In a preferred embodiment, each sprayer consists of an orifice for gas, from which an intermittent stream of pressurized gas is directed onto the substrate to be dyed. Along the course of the stream of gas there is a nozzle from which there is a continuous flow of liquid dye. When it is desired to dye, for example, in response to a data pattern (template), the stream of gas is rapidly connected up and disconnected cyclically, thus atomizing the dye which emerges from the nozzle and discrete spraying pulses are established which meter out a controlled amount of dye onto the substrate. When the stream of gas is interrupted, the nozzle projects an interrupted stream of liquid dye which does not come into contact with the substrate. <IMAGE>

Description

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70 649 1602A

The present invention relates to a device and process for spraying liquids to a moving substrate. More in particular, the invention described herein relates to a device and method by which a movable substrate may be dyed with a discrete and / or diffuse pattern. It is particularly suitable for the application of paints or other marking materials in movable textile fabrics, such as cloths, rugs or the like. The term liquid marker material, in the sense given herein, will include, in addition to paints or the like, materials which serve to bleach or otherwise modify a previously dyed substrate, as well as materials which, when applied, prevent, retard or otherwise modify the action of one or more paints, subsequently applied. It is known to apply liquid paints to moving substrates, particularly textile fabrics, from various streams which are directed to the materials and selectively controlled to produce the desired pattern. It is also known, in connection with such processes and devices, to use a control fluid, usually air, as a means for controlling the flow of liquid paint. While various techniques and approaches to such control have been used, such fluid control processes normally employ one of several approaches. In a first approach, as disclosed, for example, in U.S. Pat. 3 985 006 or 3 969 779 or 4 095 444, an ink stream is directed to the desired substrate and a transverse control fluid stream is used to divert current to a barrier or collection tank or the like in response to an externally provided pattern information or inversely when it is not desired to dye the substrate. In a second approach, as described, for example, in U.S. Pat. 3 443 878 or 3 570 275, an ink curtain is directed in a narrow spaced relationship parallel to the desired substrate and one or more fluid streams are directed through the curtain towards the substrate, thereby causing the curtain ink to shift from the substrate. In a third approach, as set forth, for example, in U.S. Pat. No. 4,501,038, a stream of control fluid, such as air, is directed to a mixing chamber into which an amount of paint is input according to a pattern information. The chamber may be positioned very close to the desired substrate, and may be configured such that, for example, air enters the chamber from the top, intersects an ink flow entering the chamber laterally and causes an ink spray to escape and of air from the boundaries of the chamber through a conduit extending from the base of the chamber to the desired substrate.

Such prior art approaches are believed to have inherent operating disadvantages that either impair their commercial utility or limit their general utility of pattern dyeing or become inappropriate to generate dyed pattern products of the type they are contemplated herein, as will be described below.

These products can be divided into two basic categories. The former may be referred to as &quot; diffuse pattern product &quot; in which the desired substrate was dyed with a pattern which exhibits soft and diffuse color outlines and may also exhibit color tones that overlap and blend almost imperceptibly with one another , the product can literally display dozens, or hundreds of different colors, shadows, or tones throughout the pattern area. The second category may be referred to as a &quot; random pattern product &quot; in which the color distribution within zones on the substrate, or along the entire substrate, has a random or pseudo-random appearance. The color may be in the form of spots or spots, or may be in the form of large areas having irregular outlines of random appearance. These products may sometimes exhibit features which are a combination of these two categories where, for example, irregular color fragments exhibit fuzzy outlines and contain a multiplicity of various shades or tones and which optionally may contain randomly distributed and / or overlapping color spots in localized portions of the substrate.

It is believed that none of the foregoing prior approaches can satisfactorily generate such standard substrates in a controlled and substantially reproducible manner, particularly where, as part of the pattern, relatively large zones of substrate are to be dyed with a single shade, or a shade blend, which should exhibit a high degree of uniformity of product appearance (and pattern), or where it is desired that extremely small random color stains of color be generated with a consistent and commercially reproducible visual effect. It is known, for example, that simply by directing an ink stream to a moving substrate may not result in a uniform and reproducible dyeing zone, but tends to produce irregularities in the front and back portions of the dyed areas and which will tend to show, in an exaggerated manner, the effects of any slight variations in the speed of the substrate as a very visible variation in the width of the type of the line. Similarly, it is believed that achieving the ability to dye near adjacent small zones accurately, even if the contours of the zone are to appear diffuse, is not merely a matter of assembling the prior art components into a more compact format. Problems involving ink stream overlap and interference and fluid flow control and fill, and valve speed must be exceeded. In addition, any system that depends on the rapid interruption of the flow of a fingering fluid must be able to cope with the effects of &quot; water hammer &quot;, which can seriously damage the execution of the pattern and cause havoc to the valves and conduits of the device, as well as the problem of avoiding contact of the ink with the substrate during non-standardization intervals &quot; and to contain such ink. The present invention relates to a device and method by which, in a preferred embodiment, a few sets of closely spaced dye or ink streams are normally directed to rails 5-

70 649 1602A corresponding collection; in a preferred embodiment a bias or lip surface is used to intercept the streams and to channel the liquid ink to the respective collection chute. Each stream in a given set is associated with a source of pressurized air or other fluid which, under command, forms and directs an atomized stream or jet of such fluid in a path which puts the stream of atomized fluid in contact with the liquid ink while the ink streams are transformed into a mist of divergent droplets of various sizes of ink which are impelled by combining the liquid or air currents in the direction of the substrate to be marked, Interrupting the atomized fluid streams in an oscillatory form, thereby causing the fluid to contact the liquid in extremely short duration pulses, and overlapping in such oscillatory pulses instructions standards, which control the number of such pulses to be m performed individually by each stream of atomized fluid in each oscillation sequence, uniform reproduction of patterns of various solid colors or various tones is possible. By employing such controlled pulses as well as by varying the distance the resulting spray has to travel to reach the substrate and / or by adjusting the relative physical position of the bias surface, the sources of liquid stream and stream of fluid and the substrate, that the droplet size distribution and the degree of droplet dispersion can be carefully controlled to meet intricate patterns having a great subtlety, delicacy and variety that can be produced with a high degree of reproducibility, Providing non-simultaneous actuation of adjacent streams of atomized fluid along a given set a wide variety of side-by-side or fill-in (i.e. across the substrate bandwidth) patterns can be produced. By providing a multiplicity of assemblies, multiple combinations of colors, or, if preferred, combinations ink and decolorizing materials or paint-resistant materials or other paint-modifying compositions.

70 649 1602A

As shown in the Figures, the invention is particularly well adapted to produce patterns incorporating &quot; random effect &quot; explained above. The invention and its advantages will be better understood by reading the description of the preferred embodiment below, when read in conjunction with the accompanying Figures, in which; Figure 1 schematically illustrates an elevational view of a device embodying the invention which may be used to standardize a continuous web of substrate, Figure 2 shows, schematically, a spray generating assembly of the type represented by 100 in Figure 1 , and the associated ink and air treatment device; Figure 3 shows, in cross section through a vertical plane perpendicular to the longitudinal axis of assembly 100 and bisecting ink tube 130, a side view of the spray generator of Figure 2; Figure 4 shows a plan view of a portion of assembly 100 shown in Figure 2, as seen from line IV-IV of Figure 3; Figure 5 shows a cross-sectional view of a portion of a spray generator illustrating a position of the ink nozzle 132 of Figure 3, as seen from line V-V of Figure 4; Figure 6 is a view similar to Figure 5, showing the nozzle 132 in a different position; Figure 7 illustrates a portion of assembly 100 as seen by lines VII-VII of Figure 5, Figure 8 is a cross-sectional view, along line VIII-VIII of Figure 7; Figure 9 is a cross-sectional view along line IX-IX of Figure 8, showing the V-shaped notches useful for aligning the intersecting air and ink streams; Figures 10 to 14 are photomicrographs (0.2X) showing the surface of the pattern-dyed knitted fabric of Example 1; -7-

70 649 1602A Figure 15 is a photomicrograph (1.1X) showing the surface of the woven cloth of Example 2,

Referring more specifically to the Figures, Figure 1 diagrammatically shows an overall side elevational view of a device suitable for patterning a web of mobile substrate fabric in accordance with the teachings given herein. While any substrate fabric capable of being dyed, or dyed to pattern by procedures such as those shown below may be used a preferred material is a textile substrate such as fabric or carpet in the form of a web; the term fabric will be used hereafter without any intention of unnecessarily limiting the explanation hereinafter. The fabric web 10 is supplied from any suitable source and is led over the rollers 12, 14 and underneath the valve housing 200 to the roller 16, which rotates in bearings associated with the platform 26. The substrate 10 is then directed towards the inside of the rolling structure 20, which is supported on the wheels 22 and which can be moved along the track 24 to adjust the distance between the frame 20 and the valve housing 200, and, accordingly, between the assemblies 100 and surface of the substrate 10. This allows the effects of varying the spacing between the assemblies 100 and the face of Substrate 10 to be easily and immediately observed. The substrate 10 is directed around the rollers 40, 42 and 44 s through the driven contact rollers 46, 48 and is then presented in a preferred embodiment in a substantially vertical orientation relative to the plurality of spray generator sets 100 mounted to the face of the valve housing 200. As shown in Figure 1, in a preferred embodiment, the substrate 10 may be separated from a backing member 50, which may be made of plastic or other paint impermeable material, by spacers 52, 54, positioned along the top and base edges of the backing member 50, above and below the level of the spray generator assembly 100, thereby ensuring that there is no contact between the back of the substrate 10 and the backing member 50. This prevents unwanted smearing from the back of the fabric and prevents excessive saturation or accumulation of visible ink on the fabric face. In a particularly preferred embodiment, the lower spacer 52 may be in the form of a trough-type manifold, which may serve to collect the sprayed liquid, which may pass through the substrate 10 and be collected in the backing member 50, the substrate 10 is then directed above the roller 60 and above the tension generating roller 62, which may have a rubber covered surface or the like and which may be over-driven, to ensure that the substrate 10 is relatively stretched in the region opposite the assemblies 100. As is shown, the substrate 10 may then be guided to appropriate ink fixing means 30 or to another processor in addition to the treatment.

Figures 2 and 3 illustrate, in varying degrees of detail, a preferred embodiment of the spray generator of the type represented by 100 in Figure 1. Figure 3 shows a partial cross-sectional view along a vertical plane perpendicular to the longitudinal axis of assembly 100 and across the longitudinal axis of the ink tube 130 of Figure 2. The elongated assembly 100 comprises a plurality of individual spray generators, each comprising an ink tube 130 and a spout 132 through which the liquid or other paint marking material may be pumped, and a dispersion aperture 140 and an associated surrounding portion 142, through which a relatively high pressure dispersion fluid such as air or other gas may be prevented. The individual spray generators are mounted in line with an adjacent spacing appropriate to the desired degree of definition. It is believed that adjacent side spacings of between about 0.5 inches and 2.5 inches, measured from the center lines of dispersion apertures 140, may be used adjacent the assembly 100, with good results spacings outside this range if a minimum overlap between adjacent spray patterns on the substrate is desired.

In the following discussion ink will be taken as the chosen marking material and air as the dispersing agent fluid,

70 649 1602A, although other marking materials and other gases or fluids may be used for particular purposes.

As shown in Figure 2, there is also associated with the generator an electronically controlled valve which is interposed in the pressurized air lines 202 and 204 and which serves to supply the aperture 140 with pressurized air from the communication tube 220, which in turn is suitably connected through the regulator 206 and the filter 208 to a pressurized air source 210. The valves 260 are, in a preferred embodiment, of the pneumatically actuated electric type, such as those distributed by Lee Company of Hestport, Connecticut. There is associated with each ink tube 130 an ink supply line 102 extending from the communication tube 120, which in turn is fed through the pressurizing pump 114, the filter 112 and the associated conduits, from the ink reservoir 110. The ink conduits 104 and 106 supply the reservoir 110 with an excess of ink from the communication tube 120 and with collected ink that is expelled by the nozzle 132 into the containment channel 162, thus forming, in one embodiment an ink recirculation device. The elongate, wedge-shaped assembly 120 of the assemblies, as shown in Figures 2 and 8, is constructed with a series of "V" -shaped grooves or grooves. 302, 304, spaced along their length (see Figure 9) in precisely opposite pairs along the top and bottom of the frame 110, at intervals corresponding to the desired spacing between the ink tubes 130 and the apertures 140. The conduits of air 114 may then be disposed within the V- 304 directly opposing the ink tubes 130 and connected to respective air lines 202. By aligning the grooves 302 with the intention of accommodating the air ducts 114 and the corresponding grooves 304 in order to accommodate the air ducts 114, the alignment of the intersection of the corresponding ink and air streams which is required to achieve maximum ink stream fragmentation can be more easily controlled. The ink tube positioning plate 310 and the air duct positioning plate 320 are formed to be secured to the frame 110 by the laterally spaced screws 342, which hold the ink tubes 130 and the air ducts 114 within the V-shaped grooves, due to the centralizing nature of the &quot; V &quot; 302, 304 (as compared to other possible conformations of the cross-section of the grooves) no further technique is required since the grooves 302 and 304 have been positioned directly opposite each other. Alignment pins 345 may be used to ensure correct alignment in the positioning plate assembly with respect to the frame 10. The assembly 100, comprising the frame 110 and the positioning plates 310, 320, is conveniently connected through the rigid member 290 and the mounting screws 344, to the front surface of the valve housing 200.

Although the angle shown between the ink tubes 130 and the air ducts 114 is shown to be about thirty degrees, this is merely a preferred embodiment. Angles smaller than and greater than that shown may be advantageously employed under certain conditions, provided that the pressurized ink stream is not sent in a path from the nozzle 132 which, in the absence of an interaction pulse or a gas stream, would result in a continuous contact with the substrate. The air conduit 114 is flanged so that the air at pressures of 413.4 kPa or more can be transferred to a replaceable opening 140 of the discharge port from the supply lines 202 (two of which are shown in Figure 3, merely to indicate a suggested arrangement for the closely adjacent lines 202). The supply line 202 is connected to the air manifold 220 (Figure 2) through recesses 214 in the housing housing front wall 212 of the valve 200. In one embodiment, the air valves 260 are positioned very close to the fittings 214 and can be disposed in a Pneumatic circuit similar to a circuit board. This pneumatic circuit board or &quot; valve chart &quot; can be equipped with suitable

70 649 1602A - so that the valve card, in which a plurality of individual air valves have been placed to individually control a plurality of individual spray generators, can simply be engaged with corresponding fittings 214, mounted on the inner part of the wall In such an embodiment, an appropriate number of valves 260 as shown in Figure 2 may be considered individually mounted on such a valve card with multiple valve charts mounted adjacently to provide control over the entire assembly 100 .

Associated with each aperture 140 is a surrounding or surrounding part 142, through which the nozzle 132 extends through a surrounding aperture 144. The surrounding portion 142 tends to maintain the high velocity of the dispersion medium jet formed by the aperture 140 and to direct the jet towards the substrate. Operation without the surrounding portion 142 or a similar surrounding portion would result in a process that would generate an unwanted cloud or mist of paint which would be difficult to control in terms of location, degree of mixing of the adjacent sprays, etc. The nozzle 132, fed with pressurized ink through the supply line 102 and the ink supply manifold 120 is associated with the tube 130 which fits within the &quot; V &quot; 302 of the wedge 110. The relative position of the nozzle within the surrounding portion 142 may be adjusted as shown in Figures 5 and 6 by moving the tube 130 into the groove 302 and securing the tube 130 in the desired position by means of a set It has been found that this adjustment alters the nature of the spray by altering the radial distance from the axis of the air jet emerging from the aperture 140, and thereby altering the character (e.g. speed, pressure, etc.) of the region within the air jet in which the paint is expelled from the protected edges of the nozzle 132. While positioning the nozzle 132 substantially above the axis of the aperture 140 is preferred, it is preferred that the Peak 132 is positioned within the surrounding portion 142 In one embodiment,

Particularly preferred embodiment, the nozzle part 132 is positioned at a very short radial distance from the axis of the aperture 140, such that, whenever the gas stream associated with the aperture 140 is activated, the liquid leaving of the nozzle 132 is immediately influenced by the jet and does not have the opportunity to form a defined and coherent current, except during interruptions in the gas flow of the aperture 140.

Perpendicular to the longitudinal axis of the ink nozzle 132 and, in the embodiment shown in the Figures, generally located opposite the aperture 140 and parallel to the assembly 100, there is a deflecting lip or surface 160. The surface 160 is mounted in such a way that the ink out of the nozzle 132 will, in the absence of a disturbing current from the aperture 140, form a stream which traverses a path terminating in the bias surface 160 and flows into an associated containment chute 162. The ink may be pumped, from the trough 162, through the ink tank 164 and the conduit 106, back into the ink reservoir 110 for reuse, or may be pumped into a suitable waste reservoir. In the preferred embodiment shown, the surface 160 may be mounted within the chute 162 and extend upwardly therefrom, and is preferably mounted by suitable conventional design adjusting means such that the degree to which the surface surface 160 extends to or beyond the course of the ink stream as well as the relative spacing and alignment of the surface 160 relative to the plurality of nozzles 132 and surrounding surfaces 142 in the assembly 100 can be adjusted. It is possible that the surface 160 is relatively stiff or may be a flexible and relatively thin blade to which stiffness is given by squeezing each blade end and applying appropriate tension along the length of the blade.

In operation, the liquid ink continuous stream tends to produce some droplets, which are substantially larger than the fine mist commonly associated with an atomization process such as is employed herein. For the purposes in view, the term &quot; microscopic fragmentation &quot; will be used to describe the process-

70 649 1602A whereby the liquid ink is fragmented into a relatively fine mist, i.e. wherein the average droplet diameter is generally and substantially smaller than 0.1 or 0.2 millimeters. The &quot; macroscopic fragmentation &quot; will be used to describe the process wherein the liquid paint is fragmented into droplets having an average diameter in the order of about 0.1 or 0.2 millimeters, or greater.

It is believed that when a continuous stream of ink is interrupted by the air advance current, the ink stream is atomized in the current zone directly in line with the forward wave front of the pressurized air, resulting in the microscopic fragmentation of the ink. The portion of the ink stream immediately above or below this in-line region remains coherent, but tends to be entrained at the periphery of the air stream passing through it tends to break into relatively large droplets and uneven ink smears is, undergoes macroscopic fragmentation) which are impelled in the substrate die.

Where the paint stream takes a perpendicular impact through the air stream, microscopic fragmentation occurs and a relatively fine mist is generated and propelled towards the substrate. In the configuration of the device shown in the Figures, a part of this mist usually strikes the bias lip 160 and coalesces therein as liquid paint. As the air stream reaches the diverting lip zone, a portion of the air stream tends to collide on the inside of the lip and tends to push some paint that may be there, either as a result of the coalescing mist or because it was the target of the interrupted ink stream, away from the collision zone. Some ink is pushed down to a collection chute 162, but some is pushed upwardly towards the edge of the shifting surface 160, and is finally pushed over the edge and is drawn by the stream of air towards the substrate, in the form of large droplets and irregularly shaped blots (i.e. products of macroscopic fragmentation).

Details of the process and operation of the device may be better described with reference to Figures 2 to 7.

70 649 1602A

The valves 260 associated with the air supply lines 202 prevent air from passing through the discharge port 140. As a result, the ink can flow from the nozzle 132 to the bypass surface 160 without interruption as shown in Figures 3 and 4, where it is dissipated and collected in a containment chute 162 and in the drip tank 164, and finally pumped back to the ink supply manifold 120 in a pressurized form or is discarded.

Figures 5 and 6 depict the in-use ink dispenser in which 140 air pulses generated by the rapid actuation and decoupling of valves 260 are fed into the aperture 260. As shown in Figure 5, the pressurized air entering the bore 114 and passes through of the aperture 140 forms a jet that interacts with the ink flowing normally in a continuous and uninterrupted stream from the tip end 132 to one side in front of the bias surface 160. In the preferred embodiment shown, the tip end 132 is positioned within the area occupied by the jet, in such a way that a. ink is influenced immediately as it exits the nozzle 132. This position tends to suppress the formation of relatively large smudges, spots and drips associated with macroscopic fragmentation, and tends to increase the formation of the fine mist associated with microscopic fragmentation

As a result of the interaction of the relatively low pressure paint stream (typically about 1.38 to about 27.56 kPa) with the relatively high pressure stream or jet (typically about 34.47 to about 413.4 kPa) in or in front of the surrounding part 142, the ink stream is dramatically separated, and is usually transformed into a shower of divergent droplets. In a preferred embodiment the ratio of the pressure of the dispersing material to the pressure of the marker material will generally fall within the range of about 5 to about 60, but may fall outside this range under certain conditions. For example if high viscosity marker materials are used, higher dispersion pressures than usual may be desired,

70 649 16G2A said ratio exceeds BQ.

A variety of different droplet sizes are produced, which are generally impelled towards the surface of the movable substrate web 10, which typically can be positioned from about 2.54 to about 33 cm from the nozzles 132, Varying the respective pressures of the ink and air streams, the viscosity of the ink, the degree to which the nozzle 132 protrudes through the surrounding discharge orifice 144 is introduced into the stream of air or jet flowing from the aperture 140, as well as other factors (e.g., the extent to which the containment lip is extended to the zone in which the spray paint is generated, the distance between the nozzle 132 and the bias surface 160, and the distance between the nozzle 132 and the substrate 10, a wide variety of visually attractive commercial products can be generated in a reproducible manner. The adjacent spacing of the individual nozzles 132 and the apertures 140, comprising a plurality of spray generators spaced along the longitudinal axis of the assembly 100, is generally secured to a given device so as to maintain a proper alignment. Such spacing is preferably such that, for a given distance from the nozzle to the substrate, the spray patterns of immediately adjacent spray generators have substantially overlapping paths, allowing overlapping and mixing of the spray patterns through relatively large percentages of the spray path between the nozzles 132 and surface of the substrate 10 as shown in Figure 7. In a preferred embodiment the included angle of the spray pattern may be in the range of about 25 to about 50 degrees, the adjacent spacing may be from about 0.762 to about 1.524 cm , and the distance from the nozzle to the substrate may be about 5.09 to about 20.32 cm; under such conditions, the overlapping and mixing of the spray generated not only with immediately adjacent nozzles 132 but with nozzles 132 spaced apart from each other by two or more nozzles has been observed. Such mixing and substantial overlapping of the individual spray patterns is believed to be while the spray droplets are dispersed,

70 649 1602A fflovem in the direction of the substrate contributes greatly to the mixing and diffusion which characterizes the diffuse pattern product &quot;.

In a preferred embodiment, the air flow control valves 260 for the aperture 140 are actuated by computer control means, indicated in Figure 2 as 270, which allow each of the individual ink streams to be selectively interrupted in response to the externally provided pattern of data, thereby providing the ability to reproduce complex patterns. Computer control may also be used to accommodate variations in ink pickup or ink deposition requirements between different types of substrates as well as variations in the speed of the substrate as it is drawn through the device. This can be achieved in a manner similar to that described in U.S. Pat. 3,844,413; 3,969,769; or 4,033,154.

As established therein, a digital rotary motion encoder, not shown in these Figures, is associated with the movement of the substrate through the structure 20. This provides a signal corresponding to the linear path of the substrate 10, which can then be used to measure an amount of predetermined ink, at a fixed length of the substrate region, in a reproducible manner.

For explanation purposes, a cycle time T may be defined as that period of time which corresponds to the time required for the substrate to travel any short distance, representing the boundary of the desired pattern detail, in the direction of the substrate path, that is, 0.254 cm. For a substrate speed of 1.524 m per minute, 0.254 cm of the substrate path is 100 milliseconds. Therefore, in the case where 0.254 cm is chosen as the minimum level of detail of the desired pattern along the length of the web, and where the web speed is 1.524 m per minute, the time cycle T will be set to 100 milliseconds. This time cycle T does not only represent the time interval necessary for the band to advance 0.254 cm, but also represents the time interval -17- /.·ν

70 649 1602A between the initiation of an air pulse (and hence the spray of the ink) and the initiation of the following air pulse. The desired duration of each air pulse within each 100 millisecond cycle, and therefore the duration of spray directed to the substrate, can be determined by considering the amount of ink collected or the ink deposition requirements dictated by the nature of the ink and substrate used. The role of standard data, which can be supplied via a magnetic disk or other means, is to specify, by default command, the required number of individual cycles of 100 milliseconds, in which the supply of air for each of the spray generators will be actuated so as to form the necessary sets of ink droplets necessary to generate the required pattern or to cover the appropriate zone of the substrate with the proper amount of paint. The overall effect is to generate a series of discrete spray droplets or clouds emanating from each spray generator on the individual cloud size and the spacing between cloud groups is determined by the data pattern, by the nature of the ink and the substrate , etc. By adapting this single spray approximation per cycle / multiple cycles per pattern command, variations in substrate speed can be completely ignored, since the ink is being measured in the substrate, in response to the true movement of the web, and not in response to an assumed substrate band speed or at the passage of an arbitrary time interval.

In the above example, the ink pickup requirements assumed require the ink to be applied for 20 milliseconds in each 100 millisecond cycle. Therefore, the air supply associated with each spray generator over set 100 required to dye to pattern at that time can be turned on for 20 milliseconds and off for 80 milliseconds, then turned on for 20 milliseconds. etc. to form pulses of pulverized droplets of uniform size (i.e., the size generated by an air pulse of 20 milliseconds) at intervals of 100 milliseconds, until the number of cycles of bonding / off imposed by the data standard for a specific spray generator, has occurred. If the substrate is now slowed to half its previous speed, the time spent by the web to advance 0.254 cm is now double, thus doubling the cycle time T, 0 &quot; dwell time &quot; of the substrate in front of the spray generators is now double its previous value. However, the ratio at which the paint is applied by the individual spray generators when the air supply is turned on is constant. If the same amount of paint is to be applied within a 0.254 cm extension of substrate as before, the the time lag during which the air supply is switched on remains at its predetermined level, i.e., 20 milliseconds; however, the time it is off may be extended to provide a global cycle time equal to the new time taken by the substrate to advance 0.254 cm. In this example, therefore, slowing the substrate velocity to half its previous value causes the aforementioned computer control to generate pulses of pulverized droplets of the same size as before, but at intervals of 200 milliseconds.

By constantly monitoring the small inevitable variations in the path of the band, and using such variations to slightly modify the time when the air supply is turned off, high quality products and pattern uniformity can be achieved. Due to certain restrictions related to valve response time, etc., it is recommended that the band speed is not increased (thus decreasing the time it is switched off) to the point where the time it is turned off is so short that the valve controlling the air flow can not be switched from on to off and back on to within the intended cycle time. Inks or other marker materials having a wide variety of flow characteristics have been used in general terms, high viscosity liquids tend to increase the degree of macroscopic fragmentation that occurs, whereas low viscosity liquids tend to increase the degree of -19-

70 649 1602 The desired microscopic fragmentation. Various thickeners, trichotonic agents, surface tension modifiers and the like have been used with interesting results. For example, the use of agents such as guar gum, which makes the liquid paint "sticky", causes the resulting ink pattern in the substrate to contain a random segment element of linear segment which resembles, in some zones with a spider web and containing blisters or irregularly shaped ink nodes positioned at various intervals along the length of the linear segments. The process and device described herein has been used to dye or color a variety of commercially available textile substrates and has resulted in many distinct visual effects. The following illustrative examples are intended to be representative only, and are not intended to be limiting in any way. EXAMPLE 1

A 100Âμ polyester knitted fabric having 16 strands per 2.54 and 34 rows per 2.54 meters and a weight of about 0.617 kilograms per 1.5 m wide was coated from behind with an SBR adhesive latex and dried. The fabric was heat-sealed, jet-dyed and again coated from behind. The fabric face was then brushed. The resulting tissue web was then treated using a device similar to that shown in Figures 1 and 2 at a fabric speed of 5.49 m per minute. The nozzle 132 was fitted within the surrounding portion 132 generally as shown in Figure 6. Three different inks were used during the single treatment. The liquid solution was made by adding Kelzan gum (marketed by Kelco Corp, of San Diego, California) to a liquid solution containing the dispersed paint to adjust &amp; viscosity at about 550 centipoise. Acetic acid was added to give a pH of about 4.5, and an antifoaming agent.

A rotary motion digital encoder associated with one of the main transport rollers in the frame 20 produces a signal 70 to the control computer 270 every 1 cm of linear movement of the tissue web, the flow rate of the solution liquid for each of the nozzles 132 was about 30 g per minute; each nozzle, laterally spaced along the assembly at 1 cm intervals, has an inner diameter end of 0.0508 cm, the central computer 270, at each encoder signal, triggers an air pulse at 241.15 kPa through apertures 140 over a period of 10 milliseconds. The selected pattern produced a series of impressions, the lines overlapping a diamond pattern. The structure 20 has been moved periodically during operation to provide a spacing between the assembly and the fabric ranging from about 2.54 cm to about 25.4 cm. The resulting patterns are shown in Figures 10 to 14 and result from spacings of approximately 2.54 cm, 7.62 cm, 12.7 cm, 17.8 cm and 25.4 cm, respectively. The resulting standardized fabric was heat set to dry and set the inks. As can be seen, the distinct pattern however in a certain way &quot; confusing &quot; of Figure 10 begins to be progressively more intensely diffuse in Figures 11 and 12 until it is nebulous in Figure 13 and largely undetectable in Figure 14. In each of the Figures, however, small spots or specks resulting from microscopic fragmentation and will become increasingly evenly distributed as the distance from the assembly to the tissue increases. EXAMPLE 2

A 100¾ polyester flat woven cloth having a finished 98 warp and 53 roll yarn construction and a finished weight of 0.217 kg was jet-dye-wiped oil as fabric prepared for printing and heat set. The fabric was treated as in Example 1, except in one detail, black and blue ink was used, the spacing of the assembly to the fabric was fixed at 27.9 cm, the resulting fabric was heated to dry and fix the ink, and is shown in the photograph of Figure 15. The ink stream, subject to macroscopic fragmentation, produced in the fabric a random-appearance pattern of spots, spots or bubbles,

70 649 1602A Irregular size. It is possible that the processes of Examples 1 and 2 are carried out using multiple colors, either during the initial process or in subsequent process repeats using the same fabric. It is still possible that other fabric constructions and face treatments (i.e., plush fabrics, velvet fabrics, nonwoven fabrics, etc.) may advantageously be treated using this invention.

Claims (10)

A method of dyeing a strip of sheet material, wherein said strip is positioned in the marker spray path, said spray being formed by the interaction of a pressurized flow of marker material and a stream of a pressurized gaseous dispersing agent, characterized in that it comprises the steps of projecting a substantially continuous liquid stream of a marker material along a path preventing it from contacting said web, forming a pressurizing dispersion stream of a gaseous dispersing agent, said dispersing stream being projected in an expanding path directed to said strip and being oriented to provide the intersection of said liquid marker liquid with said dispersing stream, said dispersing stream having maximum pressure sufficient to form, from said datum of marker material, a got shower and projecting at least a portion of said divergent droplets into said web, said pressure associated with said dispersing stream being rapidly modulated so as to form, from said direct current, a a plurality of discrete and spaced droplet pulses directed to said web, each pulse containing a controlled amount of marker material and thereby dosing a controllable amount of marker material to said web at a rate determined by the frequency and duration of said pulses, and said web moving in a path which places at least a part of said web in contact with said droplets, The method of claim 1, characterized in that said series of discrete pulses are spaced apart from droplets, being interrupted at intervals, according to the standard information, the process for dyeing a strip of sheet material, wherein said web being positioned in the marker spray path, said spray being formed by the interaction of a pressurized liquid of liquid marker material, and a stream of a pressurized gaseous dispersing agent, characterized in that it comprises steps of projecting a well defined and substantially continuous marker liquid material stream into a path intersecting a deflection surface positioned adjacent said band forming a pressurized dispersing stream of a gaseous dispersing agent, said gaseous dispersing stream being directed to a which provides for the collision of a part of said current in said band and a part and said chain in said deflection surface, said path generally being aligned with &amp; said liquid marker stream to provide the intersection of said marker liquid stream with &amp; said gas dispersing stream having a maximum pressure sufficient to form, from said liquid body of marker material stream, a droplet of marker material droplets and to project at least a portion of said droplet shower to said band varying said pressure associated with said dispersing stream in a periodic manner to cause macroscopic fragmentation of a portion of said liquid stream, as well as, to cause macroscopic fragmentation, of a part of said liquid material, to contact said deflection surface further causing microscopic fragmentation of a portion of said liquid stream, thereby forming a shower of liquid droplets comprising a relatively thin mist as a result of microscopic fragmentation, and moving said web in a path which, at least, a portion of said web in contact with at least a portion of the di to shower droplets. A method according to claim 3, wherein said periodic pressure variations comprise complete interruptions of said dispersing stream, thereby forming droplet pulses directed to said strip containing each pulse a controlled amount of liquid marker material, and dosing, therefore, a controllable amount of marker material for said band, at a rate determined by the frequency and duration of said pulses. A process according to claim 4, characterized in that said liquid stream is substantially and completely atomised by said dispersing stream, thereby preventing the flow of said liquid stream along any part of said path, except during said interruptions of said dispersing stream. A device for spraying a liquid marker material to the surface of a moving web by dividing a stream of said marker material into droplets through a pressurized gas collision stream directed to said surface, said device being characterized by comprising: (a) spray application means, comprising a nozzle for discharging: at least one stream of said marker material along a path preventing said web surface, and a gas discharge port, directed to said nozzle and said orifice being responsibly associated with a supply of marker material and pressurized gas, said nozzle and said orifice being oriented to produce respective streams which intersect at least partially , and which in the region of intersection produce a finely divided spray of said marker material, (b) valve means to the gas interposed between said nozzle and said gas supply, said valve means being capable of alternately initiating and restricting gas flow to said nozzle in a cyclic manner, independent of externally provided standard information and (e) conveying means for moving said web in a path, wherein said spray of the marker material contacts said web. A device according to claim 6, characterized in that said gas valve means is associated with a pattern information source, which generates signals which interrupt the cyclic operation of said valve means. 70 649 1602A A device for spraying a liquid marker material to the moving substrate surface by dividing a stream of said marker material into droplets through a pressurized gas collision stream directed to said surface, said device being characterized in that it comprises - (a) spray application means comprising a nozzle for discharging a stream of said marker material along a path, and a gas discharge orifice, directed toward said substrate, said nozzle and said orifice being respectively associated with a supply of marker material and pressurized gas, said orifice and said nozzle being oriented to produce respective streams which are at least partially intersected and which in the region of intersection produce a finely divided spray of said marker material; (b) gas valve means interposed between said nozzle and said gas supply, said valve means being capable of controlling the flow of gas to said nozzle in a cyclic manner; (c) diverting surface means positioned adjacently to said substrate and along said path of said marker material, to terminate said trajectory and divert said liquid streams to the collection means; (d) collection means associated with said deflecting surface means for collecting deflected liquid by said deflecting surface means; and (e) conveying means for moving said substrate in a path in which at least a part of said spray of marker material contacts said substrate. A device according to claim 5, characterized in that it further comprises pattern control means, associated with said gas valve means for actuating &quot; deactuating said valve means, and therefore controlling said gas flow to said nozzle. 70 649 1602A A device for spraying a liquid marker material to the surface of a moving substrate by fragmenting said marker material into droplets through a pressurized gas collision stream directed to said surface, said device being comprised of: ) spray application means comprising a nozzle for discharging a stream of said tracer material along a path, and a gas discharge orifice, for discharging therein a current of pressurized gas directed to said substrate, said nozzle is said orifice associated respectively with a supply of pressurized marker material and pressurized gas, said nozzle being positioned within the path of said pressurized gas stream to produce a finely divided spray by discharging said pressurized gas stream from said pressurized gas stream discharge orifice; (b) cover means axially surrounding said gas discharge port for shaping the stream of pressurized gas exiting said port; (e) gas valve means interposed between said nozzle and said gas supply, said valve means being capable of controlling the flow of gas to said nozzle in a cyclic manner; (d) diverting surface means, adjacently positioned to said substrate and along said trajectory of said marker material, to terminate said trajectory and divert said liquid stream to collection means; (e) collection means associated with said deflection surface means for collecting the deflected liquid by said deflection surface means; and (f) conveying means for moving said substrate, in a path in which at least a portion of said marker material spray contacts said substrate. -27 &quot; 70 649 IO2A The device of claim 10, further comprising pattern control means associated with said gas valve means for actuating said valve means, and thereby controlling said gas flow to the valve. said nozzle. A device according to claim 10, characterized in that said nozzle is positioned within said cover very close to the axis of said orifice. Lisbon, 12. M 1990 By MILLIKEN RESEARCH CORPORATION - 0 OFFICIAL AGENT -