HK1150640B - Apparatus for dyeing textile substrates with foamed dye - Google Patents

Description

Apparatus for dyeing textile substrates with foam dyes

Technical Field

This application is a continuation-in-part application of co-pending U.S. patent application No.11/805,893, having an application date of 25/5/2007, a publication date of 22/11/2007 and publication numbers of 2007 and 0266505-A1, of 10/833,450, of 2004-4/28/2004, publication dates of 11/3/2005 and publication numbers of 2005 and 0241078-A1, which has now been abandoned.

Background

The invention relates to an apparatus for dyeing textile substrates with foam dyes. In one form, the invention is directed to an apparatus for dyeing a textile substrate comprising cellulosic fibers with a reduced leuco-state dye that is foamed with an inert gas and applied to the textile substrate in a leuco-foam state in an inert atmosphere and subsequently oxidized on the textile substrate to affix the indigo dye to the cellulosic fibers of the textile substrate. In another form, the invention is directed to dyeing a textile substrate with a foam dye applied by a plurality of spaced apart applicators in increasing amounts.

The dyeing of cellulosic textile materials such as cotton yarn or fabrics with leuco-state dyes such as indigo dye has a wide market, especially for denim jeans articles such as jeans. The fastness of indigo dyes to cotton and the dark or light shades that can be obtained make fabrics dyed with indigo dyes a very popular product. However, dyeing cellulosic textile materials with indigo dye is a complex, complex and expensive process, since the indigo dye in its natural state cannot attach to the cellulosic fibres. In order to enable the indigo dye to be attached to the cellulose fibres, it is necessary to reduce the dye by removing oxygen, for example by mixing the dye with a hydrogen-containing reagent (bisulphite) or other reducing agent, so that the dye is a colourless leuco-state material. The dye must then be treated to maintain it in a substantially leuco state until it is applied to the cellulosic textile material. To be able to be applied, the leuco-state indigo dye must be sufficiently dilute to penetrate into the voids of the cellulosic material. Typically, the indigo dye is a paste dye supplied from a supply, for example in a 40% solution. The solution must then be further diluted with a non-oxidizing liquid, such as hydrogen containing soda and caustic soda, to a concentration of, for example, 2%, in order to maintain the leuco state of the dye so that it can penetrate into the advancing textile substrate which is impregnated with the diluted indigo dye in the vat. As a result of this dilution, it is necessary to pass the textile substrate through a series of indigo vats arranged one after the other and to expose it intermediately to the atmosphere or other oxidizing agents in order to effect color fixing of the indigo dye applied during the preceding immersion process. To obtain the desired dark or light colour, the dyeing zone generally used has any number between 4 and 8 dye vats arranged in series with guide rolls between the vats to ensure that the indigo between the vats is properly oxidised. Furthermore, the dye in the vat must be continuously and rapidly recirculated in one or more tanks to which reduced water or other similar material is added and conditioned to remove the oxygen absorbed in the vat and return any oxidized indigo dye to the reduced leuco state.

One of the outstanding problems with prior art indigo dyeing areas is the disposal of waste dye and waste water. Since a plurality of vats are provided and a large amount of dyeing liquid must be used, a large amount of dyeing liquid is discarded at the end of each dyeing operation. This creates undesirable significant expense and environmental problems.

Another prior art dyeing system is disclosed in U.S. Pat. No.4,613,335 issued to Hans-Ulrich Berendt et al on 23.9.1986. This patent discloses a process for dyeing or printing a textile material comprising cellulose with a reduced leuco-state dye in a foam carrier. Although dyeing is mentioned in the invention, the invention is primarily directed to printing and does not disclose placing the substrate in a sealed inert atmosphere. Instead, the substrate is exposed to the atmosphere as it approaches the applicator, as it passes through the applicator, and as it exits the applicator. Thus, as the substrate approaches and passes under the applicator, there is no control over the condition of the substrate and oxidation of the dye after it is applied to the substrate.

In contrast, one form of the invention places the applicator face and substrate in a controlled inert atmosphere so that the foam can be applied without or with controlled oxidation of the dye in its leuco-state, and the foam can be at least partially broken in the inert atmosphere so that the dye in its leuco-state can be spread on the substrate before being fully oxidized as the substrate leaves the inert atmosphere, without or with controlled and limited oxidation, thereby ensuring that the dye is affixed to the substrate in the desired manner when the substrate is exposed to the atmosphere.

In another form of the invention, the apparatus is not limited to dyeing any particular textile fabric substrate, and the dye may be in a leuco state or any other form, which has been subjected to a foaming treatment for application to the substrate while it is in motion. Furthermore, the apparatus is not limited to a staining chamber sealed from ambient air, but may use a sealed chamber or use a chamber open to ambient air. This form of apparatus uses a plurality of spaced foam applicators that apply dye in foam form to the surface of the substrate with an increasing amount of dye, and are spaced so that the foam can at least partially break between the applicators.

Disclosure of Invention

Briefly, in one form, the present invention provides an apparatus for dyeing a textile substrate comprising cellulosic fibers with a reduced leuco-state dye in the form of a foam. The apparatus includes a housing having an interior chamber sealed from the atmosphere and through which the substrate travels from an inlet having a seal to an outlet having a seal, the substrate entering the chamber through the inlet and the substrate exiting the chamber through the outlet. An inert gas supply is in communication with the chamber for providing an inert environment in the chamber. At least one foam applicator has an applicator face in the chamber and the applicator face extends from one side of the width of the substrate to the other side to apply foam containing the leuco-state dye to the substrate in the chamber. A foam generator generates foam containing the leuco-state dye in the absence of oxygen, and the generator is in communication with the applicator for supplying the leuco-state dye to the applicator. Thus, oxidation occurs primarily only after the substrate exits the chamber. However, small amounts of oxygen may be present in the inert gas and small amounts of controlled amounts of oxygen may be intentionally added to the inert gas in order to effect the desired controlled partial oxidation of the dye before it leaves the chamber. The inert gas supply is preferably under pressure to provide a pressurized inert environment in the chamber and to minimize the amount of any atmospheric air entering through the inlet and outlet. Furthermore, the at least one applicator is preferably spaced from the inlet so as to provide a free reach of the substrate in which air trapped in voids of the substrate can escape, and the at least one applicator is spaced from the outlet so that, before the substrate exits the chamber and the dye is oxidized, foam on the substrate can break and deposit and distribute the leuco-state dye on the substrate.

In a preferred embodiment of this form of the invention, a plurality of applicators are provided having application surfaces located in the chamber and arranged with spaces therebetween such that the foam can at least partially break and the leuco-state dye can at least partially be deposited on the substrate before the foam is applied by a subsequent applicator. A holddown element, which may be in the form of a roller, may be disposed between the applicators for engagement with the substrate to displace the substrate between the applicators to maintain the substrate in foam receiving engagement with the applicator face. The applicator is preferably parabolic in shape so as to distribute the foam evenly across the width of the substrate.

In the preferred embodiment, the inert gas is nitrogen and the foam generator generates a foam comprising nitrogen of the leuco-state dye. One advantage that results from using nitrogen in the form of a foam is that: when the foam is broken in the chamber, the nitrogen increases the amount of inert nitrogen in the chamber environment.

This form of the invention is particularly applicable where woven denim fabrics are dyed with indigo dye, which may be applied in an amount of from about 5% to 20% by weight of the fabric and preferably from 10% to 15% by weight.

In order to make the chamber accessible, the housing may have an openable cover which is sealingly mounted on the housing, and the pressing element may be mounted on a frame which is movable such that when the cover is opened, the pressing element is moved away from the space between the applicators.

In another form of the invention, the apparatus is directed to dye a traveling textile fabric substrate in a housing having an interior chamber through which the substrate travels. A feed roller assembly feeds the substrate into the chamber and an exit roller assembly pulls the substrate out of the chamber. A plurality of spaced foam applicators are disposed in the chamber and have applicator faces extending transversely relative to the advancing substrate for applying dye in foam form to the surface of the substrate in progressively increasing amounts, with spaces between the applicators being such that foam between applicators can at least partially break, thereby facilitating application of dye by a subsequent applicator. In order to maintain the travelling substrate in contact with the foam transport face of the applicator, the holddown elements may be in the form of rollers extending between the applicator at a level below the level of the applicator face. The holddown elements are preferably idler rollers and are intended to minimize the increase in stretch in the advancing substrate as it advances over successively arranged applicators, the depth of the holddown elements between the applicators decreasing progressively in the direction of travel of the substrate to reduce the angle of inclination and thereby reduce the stretch that causes friction. This reduction in depth can be achieved by providing the housing with a cover to which the pressing elements are attached with a spacer block in between, and the number of spaced-apart blocks decreases with successively arranged pressing elements in the direction of travel of the substrate. The chamber may be sealed from the atmosphere in the manner described above in connection with the invention, or may be vented to the atmosphere when dyed with a non-leuco-state dye. The feed roller assembly and the exit roller assembly are driven synchronously to maintain a substantially uniform tension in the substrate as it travels through the apparatus, thereby facilitating the application of foam in a uniform and increasing amount. A first holddown element or roller is mounted in front of a first one of the applicators and a last holddown element or roller is mounted behind a last one of the applicators, and the first and last holddown elements guide the substrate at a position at the same level as the feed roller assembly and the exit roller assembly.

In both versions of the invention described above, the holddown element between the applicators is preferably an idler roller or an inverted applicator with a face that engages and holds down the top surface of the applicator. During use of the inverted applicator, a dye foam is applied to the top surface of the substrate, which may have the same color as the dye, a different color than the dye, the same dye as the dye, a different dye than the dye applied by the lower applicator. Furthermore, whether only the lower applicator is used or both the lower and upper applicators are used, different applicators may be used to apply different colors and/or different dyes in the same apparatus, whether in an inert atmosphere or in ambient air.

Drawings

FIG. 1 is a side view of a stained area (dying range) in which the apparatus of one form of the preferred embodiment of the present invention is located;

FIG. 2 is a plan view of the stained area shown in FIG. 1;

FIG. 3 is an end view of the inlet end of the dyeing apparatus included in the dyeing zone shown in FIGS. 1 and 2;

FIG. 4 is a plan view of the apparatus of FIG. 3 with a portion of the cover removed;

FIG. 5 is a side view of the apparatus shown in FIG. 3;

FIG. 6 is a side view of the apparatus of FIG. 3 with the side panel removed;

FIG. 7 is similar to FIG. 6, but with the cover and roller frame open;

FIG. 8 is a view similar to FIG. 6 and showing an alternative outlet seal and drain;

FIG. 9 is a view similar to FIG. 6 showing a modified apparatus having a plurality of holddown elements in the form of an inverted applicator;

FIG. 10 is a side view of another form of apparatus of the preferred embodiment of the dyeing apparatus of the present invention with side panels removed;

FIG. 11 is an end view of the apparatus shown in FIG. 10;

FIG. 12 is a side view of the feed roll assembly of the apparatus of FIG. 10;

FIG. 13 is a side view of the exit roller assembly of FIG. 10;

FIG. 14 is an enlarged view of one of the applicators of the apparatus of FIG. 10;

figures 15, 16 and 17 show the handling of the lid of the device of figure 10 from the closed position (figure 15) to the initial vertical raised position (figure 16) to the pivoted open position (figure 17); and

fig. 18 is a plan view of a cover of the device shown in fig. 10.

Detailed Description

Fig. 1 to 8 show a dyeing apparatus 10 in one form of a preferred embodiment of the present invention, wherein fig. 1 and 2 show the apparatus as being included in a dyeing region 12. A web S of textile substrate is fed to the area 12 from a supply roll 14 or from a supply of pleating material in a supply tank 16. The substrate S is then relaxed in the J-box 18, withdrawn from the J-box by the feed roller assembly 20, removed from the feed roller assembly and moved under the cross-grid 48 on which the viewer 0 stands to monitor the dyeing operation in the dyeing apparatus 10. The substrate is drawn through the dyeing apparatus 10 by a driven pull roll assembly 22. The drive of the feed roll assembly 20 and the pull roll assembly 22 are controlled so that a desired state of tension is maintained in the substrate S as it travels through the apparatus 10. The substrate from the pull roll assembly 22 may be subjected to a supplemental treatment at a supplemental dye application station 24 where a foam applicator 26 applies a surface treatment substance, such as the same or a different dye as that applied in the dyeing apparatus 10, or any other desired surface treatment material, which may be applied to either surface of the substrate. The treated substrate is then passed through an infrared dryer 28 to reduce the moisture content to the desired level. Any other type of dryer may alternatively be used. The substrate S from the dryer 28 passes under a cross-over grid 50 and over a series of guide rolls 30 and is wound onto a driven take-up roll 32 to form a substrate roll 34 of dyed substrate S.

As schematically shown in fig. 2, inert gas is fed to the dyeing apparatus 10 from a gas source 36, which may be a supply tank containing inert gas or an inert gas generator, such as a nitrogen generator. Gas is fed through supply line 40 to the interior of apparatus 10 to provide an inert environment.

Inert gas is also fed from the gas source through the second supply line 38 to the foam generator 42, which also receives reduced leuco-state dye from the dye supply tank 44. The dye supply tank 44 is held under a seal that prevents air from entering the supply tank 44 as dye is fed from the supply tank 44 to the foam generator 42, thereby preventing oxidation of the leuco-state dye. The foam generator is any conventional type of foam generator that can utilize nitrogen to form foam with dye dispersed therein, which is then fed through the supply line 46 into the dyeing apparatus 10.

Fig. 3-8 show the dyeing apparatus 10 in detail. The leading guide roller 52 guides the substrate S from the horizontal direction to the vertical direction, under which the substrate travels. The front guide roller 52 is mounted on a housing 54 of the dyeing apparatus 10.

As the substrate S travels vertically from the leading guide roller 52, its edge E passes through a pair of opposed sensing forks 56, which sense the position of the edge E as shown in fig. 3 and 4. In response to sensing the position of the edge E of the substrate S, the servo motor 58 adjusts the end seal 60 so as to limit the foam applied to the laterally extending portion of the substrate without much foam escaping from the applicator beyond the position of the side edge E of the substrate S.

Opposite side panels 64 and corner support legs 66 are formed on the housing 54. The upper portion of the housing 54 is shaped as a chamber 68 formed by front and rear walls 70, 71, side panels 64 of the housing, a bottom wall 72, an L-shaped wall section 73 extending from the bottom wall 72 to an inlet seal 92 and an outlet seal 126, and a pivotable cover 74 which rests sealingly against the upper edges of the wall section 70 and the panels 64 and between which sealing material, such as resiliently compressible foam, is provided, or the seal may be provided by a channel containing water formed at the top of the wall section 70 and the panels 64, and the bottom edge 76 of the cover being placed within the water in the channel (not shown in the figures). The cover 74 is opened and closed by a pair of laterally spaced piston-cylinder mechanisms 78 having an end 80 attached at a central location on the cover 74 and other ends 78 attached to upstanding posts 84 extending upwardly from the top of the housing 54. To provide room for such pivoting of the cap 74, the cap is mounted on a pivot shaft 86 on which is also mounted a support rod 88 located adjacent the piston cylinder mechanism 78 and in the center of the cap 74. These support bars 88 stabilize the cover 74 during pivoting.

A viewing window 90 is formed in the cover 74 through which an observer 0 can monitor the operation of the dyeing apparatus 10 as the substrate S travels through the dyeing apparatus. At the front of the chamber 68, an inlet seal 92 is provided through which the substrate S enters the chamber 68. The inlet seal 92 is formed by two pairs of spaced apart inflatable pockets 93 which prevent air from entering the inert environment within the chamber 68. Above the inlet seal 92, an inlet guide roller 94 guides the substrate S to a plurality of longitudinally spaced foam applicators 96, 98, 100, 102 and 104. The guide roller 94 is located below the level of the face 106 of the first foam applicator 96 to ensure positive engagement of the substrate S with the applicator face 106.

Applicators 96, 98, 100, 102 and 104 are mounted to bottom wall 72 by flanges 103 on the applicator secured to bottom wall 72.

A pinch roller mounting frame 108 is mounted above the foam applicator 96. The frame 108 mounts four pinch rollers 110, 112, 114 and 116 on its underside. These pressure rollers 110, 112, 114 and 116 are disposed between the foam applicators and project downwardly below the level of the face of the applicators, thereby forcing the substrate S to deflect downwardly between the applicators, thereby ensuring positive engagement of the substrate S with the applicator face 106.

The frame 108 carrying the pinch rollers 110, 112, 114 and 116 pivots on a pivot axis 178 that is spaced in a rearward and upward direction from the last foam applicator 104. The frame is held in the operative position by wing nuts 180 which may be attached to the upright brackets 122 located in front of the first foam applicator 96. A coil spring 121 secured to the rear wall 71 of the chamber 68 and a rearward extension 140 of the frame 108 biases the frame 108 to the open position such that when the wing nuts 120 are released, the frame 108 will pivot upward into the open position.

Beyond the last foam applicator 104, exit guide rollers 124 are mounted below the level of the foam applicator to guide the substrate S away from the foam applicator and down through outlet seals 126 having pairs of spaced apart inflated sealing vesicles, with the outlet seals 126 and vesicles 128 being identical to the inlet seals 92 and vesicles 93 to prevent atmospheric air from entering the chamber 68.

Spaced below the exit seal 126 are guide rollers 130 that guide the substrate in a vertically downward direction and then in a horizontally outward direction to the pull roll assembly 22.

The inlet seal 92 and inlet guide roller 94 are spaced from the first foam applicator 96 so as to provide free reach of the advancing substrate within which air that may have been carried in the interstices of the substrate S and thus into the chamber 68 will have a chance to escape from the substrate interstices, thereby substantially avoiding any undesirable oxidation of the reduced leuco-state dye as it is applied to the substrate.

The foam applicators 96, 98, 100, 102 and 104 are spaced from one another so that as the substrate travels from one foam applicator to the next, it is deflected by intermediate guide rollers 110, 112, 114 and 116 to provide free time between the applicators so that the foam can break and the dye is dispersed before it is applied by the next applicator. Similarly, the exit guide roll 124 and the exit seal 126 are spaced from the last foam applicator 104 so that the foam can break and the dye can be dispersed before the substrate exits the inert atmosphere within the chamber 68 and the dye is exposed to atmospheric oxygen at a location beyond the exit seal 126.

In the preferred embodiment shown in fig. 1-8, each of the foam applicators 96, 98, 100, 102 and 104 is a parabolic applicator of the type disclosed in U.S. patent No.4,655,056, issued to Dieter FZeiffer on 7.4.1987. Applicators of this type are particularly useful in: such a parabolic foam applicator achieves an equal distribution of foam and allows the foam to be distributed equally from the input device over the full extent of the applicator face. Other types of applicators may be used with different results.

The applicator in the supplemental dye application station 24 may also have a parabolic shape, particularly if the dye application station applies foam, but in other types of applicators any other type of dye or other surface treatment substance may be applied.

As can be seen in fig. 6 and 7, the grooves 131 located at each side of the chamber 68 and outside the applicator are inclined at a central position towards a drain 132 collecting any excess dye or other liquid and having a closure 134 which can be opened at the end of the dye run cycle so that the chamber 68 can be flushed. The closure 134 is also opened upon activation when nitrogen or other inert gas is supplied under pressure from the inert gas source 36 into the chamber 68. When atmospheric air is heavier than nitrogen, the introduction of nitrogen under pressure will cause atmospheric air to be expelled from the enclosure 134. When all or substantially all of the atmospheric air is exhausted from the chamber 68, the enclosure 134 is sealed and the substrate S is threaded with a lead plate or other device to begin operation. Alternatively, the substrate may be threaded prior to evacuating air from the chamber 68, which results in a shorter length of substrate in the substrate for perfect dyeing.

Since the inlet seal 92 and inlet guide roll 94 are spaced from the first applicator 96, oxygen-containing air is purged from the interstices of the fibrous structure, which prevents the dye liquor from being prematurely oxidized and allows the dye liquor to migrate subsurface, which if oxidized would be restricted, thereby allowing the dye to become immobilized, which results in loss of control over the distribution of the dye molecules.

However, when commercially available inert gases, such as nitrogen, contain some small amount of oxygen and when commercial inert gas generators do not produce a completely pure inert gas, then a small amount of oxygen is present in the inert atmosphere, resulting in some inadvertent slight oxidation of the dye on the substrate before the substrate exits the chamber. The invention has the advantages that: if desired, a small and controlled amount of some oxygen may be intentionally introduced in any conventional manner such that the dye on the substrate may undergo partial oxidation between dye application processes and/or after dye application before the substrate exits the chamber and the dye substantially oxidizes in the ambient atmosphere.

If acceptable, only one foam applicator may be included in the apparatus and all foam supplied through the one applicator, but it is preferred to use multiple foam applicators and each applicator applies a portion of dye, either equally distributed or selectively distributed, depending on the preference, and in the case of multiple foam application devices, much darker shades can be obtained with the same amount of dye. In the case of multiple foam applicators, each applying a relatively small amount of dye-containing foam, the migration of dye into the fiber surface can be controlled. Subsequently, a relatively small amount of foam is placed in an overlapping manner on the same fiber surface area, which will enable an enrichment of the dye. The present invention enables sequential dye application without oxidation of the dye prior to the final dye application. If the foam is applied at one applicator, rather than multiple applicators, the substrate surface fibers cannot satisfactorily absorb the larger foam volume because applying the larger foam volume at a single applicator will cause the dye to be dispersed to a greater extent into the interior of the substrate rather than concentrated on the surface fibers. This results in less moisture being absorbed during the dyeing process and thus less need for drying and less waste water being produced.

In the case of dye delivery systems filled with reduced dye in the space, the dye liquor itself, which is applied to the surface of the fiber in increasing amounts, may have a relatively low viscosity formulation, will provide a controlled specific injection rate. The minimum viscosity of the foam can be maintained during foam application and the foam is only in a temporary delivery state. The foam breaks almost immediately upon contact with the fiber and does not interfere with the dye injection process. The overlapping of a small quantity of dyeing liquor with increasing quantities with the time interval or injection phase between each subsequent foam application takes place with the dye in the non-oxidized state, in clear contrast to the prior art.

In this form of the preferred embodiment, the indigo dye in the reduced leuco state can be run at a normal range of finishing speeds, for example at about sixty meters per minute. A typical fabric weight is 400 grams per square meter and a typical amount of indigo dye to be applied to one side of the fabric, which may be divided into portions in any manner between five applicators, may for example be from about 5% to about 30% of the fabric weight. For example, 2% of dye may be applied per applicator in a total amount of 10%, or 3% of dye may be applied per applicator in a total amount of 15%, or unequal amounts or any combination of amounts may be applied by different applicators.

Figure 8 shows a variation of the position of the outlet seal and the discharge conduit. In this arrangement, the exit seal 136 is disposed in a horizontal manner so that the substrate is discharged in a horizontal manner, and exit guide rollers 138, disposed in a similar manner to the guide rollers 110, 112, 114 and 116, which are similarly mounted on the frame 108 in the manner shown in fig. 1-7, deflect the substrate downwardly to follow the direction of the last applicator 104 so as to be directed to the horizontal exit seal 136.

In this variation, the drain conduit 142 is located at the rear of the housing 54, and the groove 141 is inclined downwardly and rearwardly to drain liquid from the chamber 146 into the groove 141 and drain conduit 142, so that when the drain conduit closure 148 is opened, liquid is drained from the drain conduit 142.

Variables such as dye liquor flow, substrate speed, chemical formulation, nitrogen purity, fabric preparation, and fiber source can have different effects on the shade of color produced. Furthermore, although the substrate dyed with indigo in the leuco-state is predominantly cellulosic, the substrate may contain some minor amounts of synthetic fibers in order to achieve any desired result. The variation in shade can be easily achieved by varying the number of applicators engaged in the dye solution applicator, but the total flow rate will be the same. For example, it may be found that in the case of a fiber absorbency of 15% achieved by one applicator, the dyeing liquor has penetrated to the back side of the textile substrate, although if the same total fiber absorbency of 15% is achieved successively in a stepwise manner by five applicators, no significant dyeing liquor appears on the back side of the textile substrate. As the fabric exits the chamber 68, the reduced leuco-state dye is oxidized almost immediately upon exposure to ambient air.

The interesting advantages of the invention are: when the foam collapses, nitrogen used to form the foam is released into the environment within the chamber 68, thereby increasing the nitrogen content in the chamber 68 during replenishment of any nitrogen that escapes from the chamber. This reduces the amount of nitrogen that must be supplied to the chamber 68.

The number of applicators used in the apparatus according to the invention may range from one to six or more, depending on the desired application mobility. Further, the dye liquor may be applied at ambient temperature, but higher temperatures may be utilized if desired to provide certain advantages in certain fabrics and processes.

Although the figures show and the detailed description describes an apparatus having four applicators, it should be understood that: the device may be operated with all or less than all applicators actively applying the foam dye or with only one applicator included, and the device of the present invention may be manufactured with only one applicator or with any number of applicators, all of which may be in an active state or some of which may be in a deactivated state.

The pressure of the nitrogen within chamber 68 need only be slightly greater than atmospheric pressure. The degree to which this pressure is above atmospheric pressure needs to be sufficient to prevent oxygen-containing atmosphere in the environment from entering the chamber 68 and causing the applied dye to oxidize.

Instead of using an idler roller as the compacting element, an inverted applicator as shown in fig. 9 may be used. In this figure, the device 200 is similar to the devices shown in fig. 6 and 8 in that: it includes a housing 202, a first guide roller 204, an entry seal 206, an entry guide roller 208, a plurality of upwardly facing applicators 210 mounted on a platform 212, and a subsequently disposed exit seal 216.

The device 200 has an openable lid 220 similar to the lid shown in figures 6 and 8. However, it does not include a separate frame. Instead, the cover 220 has an internally located, downwardly offset platform 222 on which is mounted a hold-down element located at the same position and for the same purpose as the idler roller hold-down element shown in FIGS. 6 and 8. In this variation, the compacting element is an inverted applicator 224 that is identical to, but inverted relative to, the lower applicator 210. These inverted applicators 224 have the same compaction purpose as the rollers shown in fig. 6 and 8, and their additional role is: the foam dye is applied to the top surface of the substrate S as it passes under the applicator face 226 of the inverted applicator 224.

In the case of these inverted applicator holddown elements, the dye applied to the upper surface may be the same or different from the dye applied to the lower surface of the substrate, and a variety of different dyes may be applied by each applicator, including leuco-type dyes and standard dyes, and operation of the apparatus 200 is carried out with the inclusion of a sealed inert atmosphere or unsealed ambient atmospheric air in the apparatus 200.

Fig. 10-18 show another form of the preferred embodiment of the present invention. It includes a dyeing apparatus 300 similar to the apparatus 10 and 200 of the previous form and can be included in a total dyeing zone similar to the dyeing zone 12 of the previous embodiment. Referring to the area shown in fig. 2, when apparatus 300 is used with an inert atmosphere in the manner described above for apparatus 10 and 200, apparatus 300 of the embodiment shown in fig. 10-18 will use a similar inert gas source, foam generator and dye supply tank. This form of apparatus 300 of embodiments of the present invention may also use ambient air, in which case, the inert gas source would not be included and only the foam generator and dye source would be used, and the dye source and foam generator would not require inert conditions.

The apparatus 300 includes a housing 302 supported on legs 304 and having end walls 306, side walls 308, a bottom wall 310 and a cover 312. These walls 306, 308, 310 and the lid 312 form an interior chamber 314. To dye with leuco-state dye by the device 300, the chamber 314 may be air-tight, as in the previous embodiment, with the cover 312 sealed on top of the walls in the same manner as the cover 74 of the previous embodiment.

The traveling textile fabric substrate S is fed by a feed roll assembly 316 to a chamber 314 having three rolls, two of which 318 are vertically spaced apart and a third roll 320 is between the two rolls and creates an offset. The rollers are driven by a motor 322 (shown in figure 12). After passing through the feed roll assembly 316, the substrate S travels around a tension detection roll 324, which is mounted on a load cell 326 from which the substrate S passes through an entry end seal 328 into the chamber 314. The substrate exits the chamber 314 at the other end of the chamber through an exit end seal 330, which is identical to the entry end seal 328, and the substrate passes through an exit roller assembly 332 having a roller arrangement comprising two spaced rollers 334 and a biased roller 36, similar to the rollers 318 and 320 of the feed roller assembly 316. Motor driven rollers 334 and 336 similar to and synchronized with feed roller assembly drive motor 322.

Fig. 13 shows the exit roller assembly 332. As shown in fig. 13, a drive belt 338 travels around offset roller 336 and two spaced rollers 334 and two guide pulleys 340. The belt tensioning element 342 is adjustably mounted for contact with the drive belt 338 to maintain the belt in driving tension.

Five foam applicators 344 are mounted in the housing 312 and extend into the chamber 314. The foam applicators 344 extend through the apparatus and are spaced apart from and extend parallel to each other for sequential advancement of the substrate S over the applicator.

The applicator 344 is similar to the applicators 96-104 shown above and described in connection with the embodiment shown in fig. 1-8 and the embodiment 210 shown in fig. 9 and as disclosed in U.S. patent No.4,655,056 issued to Dieter f. As can be seen in the enlarged view of fig. 14, each applicator 344 has an L-shaped conduit 346 through which the foamy dye from the foam supply is supplied. The L-shaped conduit 346 leads into the top of the parabolic applicator 344 and is displaced therein to a slot 348 of the applicator face 350 over which the substrate travels and receives foam from the applicator. The applicator face 350 is convexly rounded so that the substrate S can cover the slot 348 without significant leakage of foam from the slot.

At the bottom of the parabolic applicator 344, a pneumatically operable ball valve 352 operates so that discharge of the applicator can be achieved at the end of the applicator or the applicator can be otherwise purged or emptied to introduce the purged material into a discharge manifold 354.

The substrate is pressed against the applicator face 350 to ensure that the foam is properly applied to the substrate without significant leakage. This is achieved by four pinch rollers 356, each located between two applicators 344, with a first pinch roller 358 located in front of the first applicator and a last pinch roller 360 located behind the last applicator. Each of the intermediate, first and last pinch rollers 356, 358 and 360 extends downwardly below the level of the applicator face 350, causing the engaged substrate S to travel upwardly to the applicator face 350 and downwardly therefrom. The first pinch roller 358 engages the substrate at the level where it enters through the entrance end seal 388, and the last pinch roller 360 positions the substrate to move from the pinch roller at the level of the exit end seal 330.

To avoid the drive mechanism being complicated and to eliminate the need for a seal for an external drive or power source, particularly when the interior chamber 314 is to be sealed from ambient air, the pressure rollers 356, 358, and 360 are idler rollers that cannot drive the substrate S without being driven under uniform tension. For this reason, all the pressure rollers 356, 358 and 360 are attached to the underside of the cover 312 in the presence of spacer blocks 362 which determine the downward extension of each pressure roller, and the number of spacer blocks 362 on which the intermediate pressure rollers 356 are mounted decreases with successive rollers in the downstream direction of travel of the substrate S, thereby reducing the depth of successive pressure rollers, resulting in a progressively decreasing angle of inclination as the substrate advances over successive applicator faces, thereby reducing the amount of friction developed which can lead to increased stretching. Uniform stretching is advantageous because it results in the amount of foam applied at each applicator being as close to a uniform amount as possible. Variations in the stretching action in the substrate will result in variations in the amount of foam applied by the applicator to the substrate surface. The amount of stretch in the substrate is controlled by the relative drive speeds of the rollers of the feed roller assembly 316 and the rollers of the exit roller assembly 332, and by gradually reducing the number of spacers 362 along the sequence of the pressure rollers. In this regard, it is desirable that the enhancement of the stretching action in the substrate as it travels through the apparatus be limited to a range of 1 to 2 and 1/2 times the stretching action in the substrate as it enters the apparatus. The spacer blocks 362 may be of any size and number that provides an optimized result. For example, spacer blocks 362 having a thickness of 1/8, 3/16, or 1/4 inches, and a number that is reduced from about 6 blocks to about 3 blocks may be used as appropriate to provide satisfactory results.

Desirably, the spacing between the applicators 344 is sufficient to cause at least partial collapse of the foam between the applicators so that the dye will be effectively absorbed in the surface fibers of the fabric substrate before the foam is applied by the next applicator. Thus, in combination with the gradual reduction in depth of the intermediate pinch rollers 356, this results in each applicator being able to apply foam relatively uniformly without much moisture being absorbed into the fabric. For the apparatus of the present invention, the amount of dye foam that is typically applied when using one applicator can now be divided into several portions and one of them applied at each applicator. For example, in the apparatus shown in the figures, one fifth of the foam dye is applied by each applicator and each portion of the applied dye is applied only to the surface of the substrate, rather than allowing a significant amount of foam dye to penetrate into the fabric as would be the case if all of the foam dye were applied at one applicator. In a typical operation, the moisture picked up by the apparatus of the present invention may comprise 15% by weight of the fabric, whereas in a conventional dyeing operation moisture is picked up to 90% to 100%. As a result, time-consuming drying can be greatly reduced or eliminated and the amount of waste water can be minimized.

To limit the discharge of foam across the width of the substrate S, side seals 364 and 366 similar to the side seal 60 of the embodiment shown in fig. 3 and 4 are provided. The edge of the advancing substrate may be sensed by a sensing fork, shown as reference numeral 56 in fig. 3, as described in the previous embodiment, or various electronic sensors may be used.

When the apparatus 300 is used to apply leuco-state dyes, requiring an inert atmosphere, the bottom wall 310 is located proximate to the upper extent of the applicator 344, thereby minimizing the volume of the chamber 314 and thus the amount of inert gas that needs to be held in the chamber. Furthermore, when leuco-state dyes are used, the space between the access end seal 328 and the first applicator 344 is large because it allows at least some of the oxygen that may be carried into the substrate to dissipate. Similarly, the space between the last applicator and the exit end seal 330 is also large because it allows the foam to at least partially collapse if the dye is secured to the substrate prior to exposure to the atmospheric environment.

As shown in fig. 11, any unapplied foam that accumulates as liquid in chamber 314 is discharged through side conduit 368 to flap 370, which may be opened manually or automatically as desired. Similarly, a drain valve 374 (fig. 10) on the drain manifold 354 may be operated to drain accumulated liquid from the drain manifold 354.

Monitoring and control of the operation of the apparatus 300 is performed by an operator 0 who performs monitoring and control using a control panel 378 installed at the entrance side of the apparatus 300.

The embodiments of the device 300 shown in fig. 10-18 may be used to apply leuco-state dyes or may be used to apply non-leuco-state dyes with substantially equal advantage. When the device 300 is used to apply non-leuco-state dyes, the chamber or the end seal need not be airtight or the cover need not be sealed in place. Conversely, there is ambient air present before and after the cover is closed and this ambient air can enter through the unsealed opening, including the opening that results from the disconnection from the inert gas supply. In addition, when the foam is broken, air is released therefrom.

Fig. 15, 16 and 17 show the sequence of operations for opening the cover 312. Figure 15 shows the lid closed during operation of the device. The first step in opening the lid is to lift the lid 312 vertically. This is accomplished by extending the shorter front piston cylinder mechanism 380 located at the bottom of the front leg 304 of the device 300. These shorter piston-cylinder mechanisms 380 are attached to the lower end of the longer front piston-cylinder mechanism 382. The upper end 384 of the front piston-cylinder mechanism 382 is attached to the front corner of the cap 312, which is raised by lengthening the shorter front piston-cylinder mechanism 380 and simultaneously lengthening the shorter rear piston-cylinder mechanism 386 mounted on the rear corner extension 388 of the housing 302. The upper end of the rear piston-cylinder mechanism 386 is attached to the corner pivot 390 of the cap 312 and the extension of the rear piston-cylinder mechanism 386 raises the rear of the cap 312 to the same height as the front piston-cylinder mechanism 380 raises the front of the cap. This initial vertical raising of the cap 312 is particularly desirable when the cap 312 is sealed during operation.

After initially raising the cover 312 vertically, the front piston-cylinder mechanism 382 is extended sufficiently to raise the front of the cover 312, in the process of which the cover pivots about the rear pivot 390 to swing the cover 312 open to the position shown in FIG. 17. As the cover 312 approaches its upper extent of pivoting, a latch plate 394 secured at an incline at the side of the top of the cover 312 engages with a latch 396 pivotally mounted on a reciprocating crossbar 397, which is mounted on and extends between upstanding posts 398, until the latch plate 394 displaces the latch 396 a sufficient distance to engage the latch 396 in an opening 400 in the latch plate 394, thus holding the cover 312 in the open position shown in fig. 17. An arm 402 fixed to and extending from one end of the rod 397 has an outer end 404 attached to a spring mechanism 406 having an end 408 fixed to the reciprocating cross bar 397 and the other end 410 attached to a bracket 412 on the post 398. The spring mechanism 406 normally forces the cross bar 397 to position the latches 396 in the downwardly extending position, as shown in fig. 10. When it is desired to pivot the cover 312 downwardly to its closed position, the latch 396 is manually or mechanically disconnected from the latch plate 394.

The spacer blocks 362 described in the form of the invention described in connection with fig. 10-18 can also be used in the form shown in fig. 1-8 and 9 in order to achieve the same object and to obtain the same advantages. Further, all forms of the invention described herein can be used for leuco-type dyes and also for other dye systems than leuco-type, such as sulfur dyes, vat dyes, conventional aqueous textile dyes, and any other dye that can be applied in foam form, and the heating system can be set to achieve the best results for the particular dye selected. Further, the textile fabric substrate may be a woven, knitted or non-woven material, which may be cellulosic, non-cellulosic or a mixture thereof. Furthermore, the applicators of any of the versions of the present invention may be provided individually or in combination by dedicated individual foam generators to simultaneously supply different dyes and chemicals to the substrate and apply layered materials.

The apparatus of the present invention is particularly suitable for dyeing substrates in fabric form, including heavy denim fabrics used to make jeans which can be dyed in any variegated pattern to highlight fashion effects, which cannot be achieved by conventional dyeing in which yarns are dyed instead of fabrics, but in conventional machines light fabrics are sometimes dyed instead of heavy fabrics.

The present invention has been described above, but it is easily understood by those skilled in the art that: the invention can have wide application and application occasions. Many embodiments and modifications other than those described herein, as well as many variations, modifications, and equivalents thereof, may be suggested by the present disclosure and the foregoing description of the invention without departing from its spirit or scope. Thus, while the invention has been described in detail herein with reference to the preferred embodiments, it should be understood that: the disclosure of the present invention shows only an example of the present invention and is only intended to fully describe the present invention. The foregoing disclosure is not intended to be, and should not be construed to, limit the present invention or otherwise to exclude any other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the following claims and the equivalents thereof.

Claims (4)

1. An apparatus for dyeing a traveling textile fabric substrate, the apparatus comprising:

a housing having an interior chamber through which the substrate travels from an inlet through which the substrate enters the chamber to an outlet through which the substrate exits the chamber;

a feed roll assembly for feeding the traveling substrate to the inlet;

an exit roller assembly for pulling the traveling substrate out of the chamber;

a plurality of spaced apart foam applicators in the chamber, the foam applicators having applicator faces extending transversely relative to the traveling substrate for applying dye in foam form to the surface of the substrate in progressively increasing amounts, the applicators being spaced apart so that foam between the applicators can at least partially break;

a plurality of laterally extending holddown elements in the chamber extending laterally between the applicators relative to the traveling substrate and at a position below the level of the applicator face to guide and hold the substrate against the applicator face;

the depth of the holddown elements between the applicators is progressively reduced in the downstream direction of travel of the substrate to reduce the angle of inclination of the substrate as it travels over successive applicator faces, thereby minimizing an increase in the degree of stretching of the substrate as it travels through the apparatus past successive applicator faces.

2. An apparatus for dyeing a traveling textile fabric substrate according to claim 1 and further characterized in that said holddown elements are mounted to said housing with a spacer therebetween and the number of said spacers for each holddown element between said applicators decreases in the direction of travel of the substrate.

3. An apparatus for dyeing a traveling textile fabric substrate, the apparatus comprising:

a housing having an interior chamber through which the substrate travels from an inlet through which the substrate enters the chamber to an outlet through which the substrate exits the chamber;

a feed roll assembly for feeding the traveling substrate to the inlet;

an exit roller assembly for pulling the traveling substrate out of the chamber;

a plurality of spaced apart foam applicators in the chamber, the foam applicators having applicator faces extending transversely relative to the traveling substrate for applying dye in foam form to the surface of the substrate in progressively increasing amounts, the applicators being spaced apart so that foam between applicators can at least partially break;

a plurality of laterally extending holddown elements in the chamber extending laterally between the applicators relative to the traveling substrate and at a position below the level of the applicator face to guide and hold the substrate against the applicator face;

the housing includes an openable cover and the pressing member is mounted on the cover.

4. An apparatus for dyeing a traveling textile fabric substrate, the apparatus comprising:

a housing having an interior chamber through which the substrate travels from an inlet through which the substrate enters the chamber to an outlet through which the substrate exits the chamber;

a feed roll assembly for feeding the traveling substrate to the inlet;

an exit roller assembly for pulling the traveling substrate out of the chamber;

a plurality of spaced apart foam applicators in the chamber, the foam applicators having applicator faces extending transversely relative to the traveling substrate for applying dye in foam form to the surface of the substrate in progressively increasing amounts, the applicators being spaced apart so that foam between applicators can at least partially break;

a plurality of laterally extending holddown elements in the chamber extending laterally between the applicators relative to the traveling substrate and at a position below the level of the applicator face to guide and hold the substrate against the applicator face;

the interior chamber being substantially air tight with the inlet and outlet air seals, the chamber being capable of containing an inert gas for effective application of the leuco-state foam dye to the textile fabric substrate without significant oxidation of the dye prior to being discharged from the apparatus; and

the housing includes an openable cover and the pressing member is mounted on the cover.