MXPA99000201A - Sealing system for improved applicator die - Google Patents

Abstract

Una boquilla aplicadora mejorada (50) para depositar alternativamente diferentes materiales líquidos de recubrimiento sobre una banda continua en movimiento, comprende un cuerpo de boquilla (52) que tiene barras conmutadoras (80, 84) para la abertura y el cierre de los respectivos conductos de flujo (60, 70) para suministrar los diferentes materiales líquidos de recubrimiento hacia un orificio alargado (68) para el recubrimiento desde los respectivos múltiples (72, 74). Las barras conmutadoras (80, 84), los conductos de flujo (69, 70) y los múltiples (72, 74) son substancialmente tan anchos como el orificio (68) para el recubrimiento y son substancialmente paralelos a dicho orificio (68) de la boquilla, con lo que el cambio entre los diferentes materiales de recubrimiento puede realizarse muy rápidamente.

Description

SEALING SYSTEM FOR. IMPROVED APPLICATOR NOZZLE CAM-O PE INVENTION The present invention relates to an improved applicator nozzle for applying a liquid coating such as a pressure-sensitive adhesive to the sheet or web in motion.

BACKGROUND OF THE INVENTION Pressure sensitive labels typically consist of a backing paper or film, a thin layer of release material normally made from silicones, a layer of pressure sensitive adhesives and a front layer, or front of paper or plastic, usually referred to as "front material". Pressure sensitive labels are usually made from long continuous rolls of label material, which are printed or marked in some way with desired marks or indications and then separated into individual labels. Conventional processes for the manufacture of continuous webs of pressure sensitive labeling material usually take the form illustrated in Figure 1. As shown in this Figure, a sheet or web P1026 / 99MX continuous backing paper 10 is desembobina or continuously unwound from paper roll 12, is passed through the station 14 printing support, through station 16 silicone coating and to the curing oven 18, wherein the silicone release layer is dried and cured. In some systems, the printing station 14 is after the silicone coating station 16. Then, the band is passed to the coating station 20 where a thin layer of pressure sensitive adhesive is applied to the silicone layer. The band is then passed to the dryer oven 24, where the pressure sensitive adhesive is dried to a sticky or sticky state. Alternatively, the pressure sensitive adhesive is solidified by cooling, such as, for example, when a hot melt adhesive is used. After passing through the dryer oven 24, the web is passed to the rolling station 26, where the web is laminated with a layer of facing material 28 continuously withdrawn from the supply 30 of the facing material. The finished web is then wound into the roll of product 31. In order to apply to the web 10 the pressure sensitive adhesive in the coating station 20, an applicator nozzle such as the P1026 / 99MX which is schematically illustrated in Figure 2. As shown in this Figure, the web 10 is passed through a backup roller 22 such that the silicone layer in the web 10 faces the applicator nozzle 34. applicator nozzle 34 includes an orifice 36 for coating arranged or disposed in approximately perpendicular to the direction of travel of the band 10, gift of width of the orifice 36 for coating is approximately as wide as the width of the band 10. this context, the "width" refers to the dimension taken transversely to the direction of travel of the band passing through the hole for coating the nozzle. The pressure sensitive adhesive is supplied to the hole 36 for coating from an inlet 38 which communicates with a manifold 40 to distribute the pressure sensitive adhesive. Throughout the entire hole width 36 for coating. Multiple 40 communicates with the hole 36 for coating through a groove or narrow and long "pre-plateau" 44 and then through a slot or elongated and even closer 48. "plateau" in the applicator nozzles type described above, the manifold 20, the pre-plateau 44 and the plateau 48 are normally arranged or arranged substantially parallel to the holes for coating the P1026.99MX nozzles and are substantially as wide as these holes. The pre-plateau 44 is also usually very long (ie, the dimension corresponding to the direction of flow of the coating material) with respect to its thickness. For example, the length / width ratios in these pre-plateaus are normally between approximately 25/1 and 50/1, while the length / thickness proportions of the plateaus are normally between approximately 50/1 and 100/1. In the nozzle illustrated in Figures 1 and 2, the pre-plateau 44 is approximately 750μm thick and 1 inch long, while the plateau 48 is approximately 100 to 200μm thick and 0.75 inches long. The manifolds, the pre-plateaus and the plateaus arranged substantially parallel to their corresponding holes for coating and substantially as wide as these same holes, are widely used in the applicator nozzles since they facilitate the uniform supply of the liquid coating material through of the entire width of the band that will be covered. Also, the plateaus are normally adjustable, so that the thickness of the applied coating can be adjusted as desired. Conventional manufacturing processes such as those illustrated in Figures 1 and 2, can operate in P1026 / 99MX a wide range of production speeds. For example, it is not uncommon for commercial modes of the previous arrangement to operate at speeds of 50 to 500 meters per minute using bands that are one meter or more in width. In addition, many different pressure sensitive adhesives can be used in these processes for the manufacture of pressure sensitive labels. For example, hot melt adhesives, solvent based adhesives and emulsion based adhesives can be used for this purpose. Also, within each of these categories, many different compositions can be used. Further, to the moving webs in addition to the pressure sensitive adhesives a wide variety of different liquid coatings can be applied using the techniques and applicator nozzles as described above. In commercial operation, it is often necessary to switch from one pressure-sensitive adhesive to another in order to meet customer demands and other performance requirements. This is commonly accomplished by switching from the pressure sensitive adhesive previously used by a new pressure sensitive adhesive upstream of the inlet hole to the nozzle. Also, the nozzle is normally closed and sometimes cleaned by passing a cleaning fluid P1026 / -9MX suitable, such as can be a soap solution, through the nozzle before the new adhesive is fed through it. In some cases, an operator passes a shim or gauge or other implement through the hole for coating, in order to ensure that no adhesive is lodged in it. Due to the relatively large mass of the web roll 10 and the need to keep the web 10 moving at constant speed during commercial operation, it is customary to keep the web 10 moving during the two or three minutes normally required to change a web. pressure sensitive adhesive to another. Because the strip produced during the changeover period will normally have an amount of pressure-sensitive adhesive out of specification or will not have any pressure-sensitive adhesive at all, it is customary to discharge all this material to the waste each time it is applied. makes a change At the production speeds normally found today, this translates into a loss of 100 to 1,000 or more meters of product during each change. In accordance with the above, there is a need for a new applicator nozzle that allows a much faster change between pressure sensitive adhesives than is possible in conventional practice. P102- / 99MX In this regard, applicator nozzles that have the ability to process two or more pressure sensitive adhesives at the same time are already known. See, for example, U.S. Patent No. 3,480,998 to von Erdberg and U.S. Patent No. 4,152,387 to Cloeren. However, these nozzles are manufactured to continuously produce multilayer coatings, not to alternately produce single layer coatings. Therefore, they are not able to completely eliminate the flow of a layer or the rapid change that is necessary to reduce or eliminate the large amount of waste reproduced in normal practice. U.S. Patent No. 4,756,271 to Gary Maier discloses an applicator nozzle that allows the change from one pressure sensitive adhesive to another to alternately produce single layer coatings. However, in nozzles of this type, sealing the nozzles to prevent leakage of one pressure sensitive adhesive to the other can be a problem. The leakage of a pressure sensitive adhesive towards the other adhesive in a nozzle layers of processing multiple adhesives can lead to a product out of specification. Also, pressure sensitive adhesives can get trapped in the "dead zones" of the P1026 / 99MX given, where they can harden, thus making the nozzle inoperative. This problem is exacerbated with the nozzles such as those illustrated in the Maier patent in which one or more flow channels are closed for prolonged periods of time. The nozzle shown in the aforementioned Maier patent uses a rotary or rotating cam to make the change between different adhesives. During this change, the front face or edge of the cam slides over the outlet channel leading to the cover hole. With this design, effective sealing can be difficult, since any sealing means supplied at the leading edge of the cam is consistently worn or eroded as the cam moves between different coating positions. In accordance with the foregoing, there is a need for a nozzle that allows not only rapid change from one adhesive to another but also has the ability to operate or operate for extended periods of time with little or no leakage.

SPM &KIQ OF INVENTION In accordance with the present invention there is provided an improved applicator nozzle including two manifolds for receiving two different liquids from P1026 / 99MX coating such as pressure-sensitive adhesives, two separate passages communicating between the respective manifolds and the pre-plateau of the nozzle, and a closing means for opening and closing the different passages for allow the coating liquid in the two manifolds to flow alternately to the pre-plateau of the nozzle and to the orifice for coating. Each of the manifolds of the nozzle and each of the respective reflux passages communicating with the pre-plateau of the nozzle are arranged essentially parallel to the width of the cover orifice and essentially have the same width as this orifice. . In addition, the closure means is adapted to open and close each flow passage by a quick or spring action. In addition, a sealing system is provided for sealing the closure means in the nozzle body of the nozzle of the invention to prevent leakage of the two coating liquids. Because the manifolds and associated flow passages of the applicator nozzle of the invention are parallel to the coating orifice and as wide as this orifice, each of the coating liquids is supplied to the coating orifice as evenly as possible. along the entire length of the hole for coating. Also, because the means of P1026 / 99 X closing opens and closes to the respective flow passages operates with a spring or fast action, switching between adhesives occurs very quickly, thus minimizing the production of product out of specification. In addition, because the closure means is mounted on the body of the applicator nozzle of the invention with a sealing system, leakage or draining of one of the two coating lines towards the other is practically eliminated as much as the leak or runoff of the coating liquids to the outside of the nozzle. As a result of these particularities, it is possible for the applicator nozzle of the invention to switch from one coating liquid to another in periods of time as short as 0.1 to 1.0 seconds. This results in the production of normally one to three meters of product out of specification instead of 100 to 1,000 meters as found in current practice. In addition, because leakage of the coating liquids is essentially eliminated, the applicator nozzle of the invention can operate for very long periods of time with little or no maintenance or shutdown. This also contributes to improved production speeds and lower waste production.

P1026 / 99MX BRIEF DESCRIPTION OF THE DRAWINGS The present invention can be more readily understood by reference to the following drawings, wherein: Figure 1 is a schematic illustration of a typical prior art assembly or installation for the manufacture of label material; and Figure 2 is a schematic illustration of a prior art applicator nozzle used in the assembly or installation of Figure 1; and Figure 3 is a schematic illustration of the improved applicator nozzle of the present invention; Figure 4 is an end view of the improved applicator nozzle of Figure 3; and Figure 5 is a partial schematic perspective view of a switch bar or closure means used in the applicator nozzle of Figures 3 and 4; and Figure 6 is a schematic end view illustrating the structure of the preferred sealing means used to seal the switch bar of Figure 5 on the body of the improved applicator nozzle of the Figure 3; and Figure 7 is another perspective schematic view illustrating the relationship of the switch bar of Figure 5 with the other elements of the improved nozzle of Figures 3, 4 and 5; and Figure 8 is a schematic perspective view illustrating the shape of the multiples of the improved applicator nozzle of Figure 3; Figure 9 is a schematic illustration of a coating system comprising the improved applicator nozzle of the present invention and the various peripherals.

DETAILED DESCRIPTION-. OF THE PREFERRED MODALITIES As shown in Figure 3, the applicator nozzle of the invention generally indicated as 50 is composed of an elongated nozzle body 52 having a width generally as wide as the width of the moving web that will be coated The body 52 of the nozzle is composed of a central section 54, an upper section 56 and a lower section 58. The upper section 56 and the lower section 58 define between them a narrow and elongated pre-plate 60 or slot. plate 60 communicates with the plate 62 defined between the upper lip 64 of the nozzle and the lower lip 66 of the nozzle. The outer edges of the upper lip 64 of the nozzle and the lower lip 66 of the nozzle define a P1026 / 99MX orifice 68 for coating from which the liquid material is deposited from the nozzle 50 on the moving band that will be coated. In accordance with conventional practice, the upper lip 64 of the nozzle and the lower lip 66 of the nozzle can be adjustable, so that the thickness of the plate 62 and, hence, the amount of liquid material deposited in the band in movement through hole 68 for coating, can be adjusted as desired. Alternatively, one or both lips of the nozzle can be fixed, if desired. In order to alternately supply the first and second liquid coating materials to the cover hole 68, the first inlet port 69 and the second inlet port 70 are defined in the central section 54 of the body 52 of the nozzle. The first inlet 69 communicates with a first manifold 72 which is defined by an elongated groove in the central section 54 of the body 52 of the nozzle. In the same way, the second inlet 70 communicates with the second manifold 74, which is also defined by an elongated slot or channel in the central section 54 of the body 52 of the nozzle. Each of the manifolds 72 and 74 are substantially parallel to the width of the hole 68 for coating and P1026 / 99MX substantially have the same width as said hole. In addition, each of the manifolds 72 and 74 can be defined in the upper and lower sections 56 and 58 of the nozzle instead of the central section 54, if desired. In order to load the liquid coating material in the manifold 72 to the pre-plate 60, a first liquid or pre-plateau 76 switching passage is provided. The first passage 76 for liquid is defined by two congruent surfaces, one of which is defined by a front end 78 of the central section 54 of the nozzle and the other is defined by a closing means or closure element, which, in the particular embodiment shown is composed of a first switching bar 80. In the same way, the second manifold 74 communicates with the pre-plate 60 by means of the second liquid passage or pre-switch plate 82, wherein the second Liquid passage or switching pre-plateau 82 is also defined by two congruent surfaces, one of which is formed at the forward end 78 of the central section 54 of the nozzle and the other is defined by the second switching rod 84. first and second fluid passages 76 and 82, as well as the corresponding switch rods 80 and 84, as well as the manifolds 72 and 74, are also P1026 /..- X substantially parallel to the hole 68 for coating and are practically as wide as this hole. A first actuator 86 includes a piston rod 88 (Figure 5) connected or integrally connected to the first switch bar 80 and a force generator 90 to generate a magnetic, pneumatic or hydraulic force on the rod 88 of the piston. A mechanical actuator such as an asymmetric cam can also be used for this purpose. The force generator 90 is of the dual action variety and, therefore, has the ability to move the switch bar 80 up or down in the upper section 56 of the nozzle body to open and close the first passage 76 of the liquid. In the same way, a second actuator 92 includes a piston rod (not shown) and a force generator 94 for moving the second switch bar 84 between the open and closed positions to allow and to prevent the flow of liquid coating material. through the second passage 82 of liquid. During normal operation, one of the switch bars 80 and 84 is in an open position while the other is in the closed position. Therefore, at any time only one of the liquid coating materials supplied from the orifice P10-6 / 99MX input 96 and 70, will flow to the pre-plate 60, the plate 62 and the hole 68 for coating. In addition, the change from one liquid coating material to the other can be done extremely quickly by reversing the positions of the two switching bars by means of the actuators 86 and 92. In other words, the passages 76 and 82 for liquid are adapted to open quickly and to close quickly due to the short travel distance of the commutator bars 80 and 84 as well as the rapid movement of these commutator bars which is possible due to the force generators 90 and 94. Thus, for example, in a nozzle in which the liquid passages 76 and 82 are 500 to 5,000 μm thick, the change can occur in as little as 0.01 to 1.0 seconds. Figure 5 illustrates the structure of the switching bars 80 and 84 in more detail. As shown in this Figure, the switch bar 80 is composed of a rigid body member 96 having a front end 98 and a rear end 100. The forward end 98 is composed of a flat and angled surface, which together with the forward end 78 of the central section 54 of the nozzle defines the first passage 76 to stop liquid. In addition, the rigid body member 96 defines an upstream side surface 102 and a downstream side surface 104, both of which are parallel P1026 / 99MX as well as parallel to the piston 88. With this structure, the switch bar 80 moves slidably in the upper section 56 of the nozzle in response to the actuation of the actuator 86 The ratio of the switching bar 80 to with respect to the other elements of the nozzle 50 it is further illustrated in Figure 7, and it will be understood that the ratio of the switch bar 84 to the other corresponding elements of the nozzle is the same. As shown in Figure 7, the switch bar 80 is mounted to move slidably in a direction parallel to the side surfaces 102 and 104 for opening and closing the first passage 76 for liquid. In addition, the downstream end 106 of the liquid passage 76 terminates at the upstream end 108 of the pre-plate 60. In addition, the first manifold 72 and the first passage 76 for liquid are connected together by the first pre-plateau. 107 of multiple, the first manifold 72 is adjacent very closely to the first passage 76 for liquid. By closely adjacent it is meant that the first manifold 72 is as close as possible to the liquid passage 76 (ie, the first manifold pre-plate 107 is as short as possible) within reasonable machining tolerances. In other words, the manifold 72 is not that close to passage 76 of P1026 / 99MX flow so that any machining out of specification would cause excessive wear on the front end of the manifold, as this would lead to failure of the nozzle 50 by wear. However, within this restriction, manifold 72 is as close as possible to passage 76 for liquid. Also, it is desirable that the commutator bars 80 and 84 and, in particular, the output ends of these commutator bars be machined as accurately as possible, since this results in virtually no dead zones or zones at the ends. of exit of the passages 76 and 82 of the commutator bars towards the pre-plate 60. In order to avoid the leakage of the liquid materials that will be processed by the applicator nozzle 50 of the invention, a sealing system indicated in generally as 110. See Figures 5, 6 and 7. The sealing system 110 includes a first primary seal 112 and a first secondary seal 114, each of which is defined on the upstream side surface 102 of the side bar 80. Located between the primary and secondary seals 112 and 114 is a fluid seal 116 that is connected to a source of cleaning fluid supplied in a continuous or intermittent manner, such as water supplied. strada at a lower pressure, for example, 5 psig, which is discharged continuously to P1026 / 99 X discarded or recirculated by exit ports, not shown. The sealing system 110 further includes a second primary seal 118, a second secondary seal 120 and a second fluid seal 122, all defined on the downstream side surface 104 of the switch bar 80. As illustrated in Figure 6, each one of the primary and secondary seals takes the form of a strip 124 of material placed substantially parallel to the hole 68 for coating and substantially as long as said hole. Each of these seals, in cross section, is preferably composed of a U-shaped member made of a flexible material such as a plastic or an elastomer, the U-shaped member carrying a U-shaped member therein. elongated spring or an initially soft polymer cord 126 for pushing the legs or legs 128 and 130 of the U-shaped member 124 in the outward direction. In the embodiment shown, the leg 130 includes teeth 132 for engaging the carrier surface 133 of the upper portion 56 of the nozzle in which the switch bar 80 is slidably received. The sealing system 110 virtually eliminates leakage of liquid coating materials between the commutator bars 80 and 84 and their associated nozzle body sections. This effectively prevents forced closing of the nozzle 50 effect P1026.99MX of the hardening of the liquid that will be coated in these areas, which can occur when using pressure sensitive adhesives. As shown in Figures 5 and 7, the end surfaces of the switch bar 80 are also arranged parallel to the piston 88 and, in the embodiment shown, perpendicular to the side surfaces 102 and 104 of the switch bar. The upper section 56 of the nozzle also defines the mating surfaces to slidably receive these end surfaces of the commutator bar, these mating surfaces are also arranged or arranged parallel to the piston 88. To prevent material leakage of liquid coating between the end surfaces of the switch bar 80 and the mating surfaces of the upper section 56 of the nozzle body, can be used to the same sealing system described above. However, in the preferred embodiment of the invention, these surfaces can be effectively sealed by forming these coupling surfaces from a suitable material such as flat sheets of fiber-reinforced Teflon® or a soft material, such as such as brass or copper. With the preceding structure, the applicator nozzle of the invention can achieve a change P1026 / 99MX extremely fast liquid coating material from one to another. This is due, in part, to the fact that the switching bars 80 and 84 move by a fast action only a very small distance between the open and closed positions. However, this is also because the passages 76 and 82 for liquid, as well as the manifolds 72 and 74 which are arranged substantially parallel to the cover hole 68 and are practically as wide as said hole. As illustrated in Figures 3, 4, 5 and 6, the passages 76 and 82 for liquid actually form "commutator pre-plates" between the pre-plate 60 and the manifolds 72 and 74 respectively. In addition, the manifolds 72 and 74 communicate with the passages 76 and 82 for liquid, by means of the respective pre-plateaus of the manifold, one of which is illustrated at 107 of Figure 7. As is well known, the pre-plateaus and the manifolds arranged and arranged in substantially parallel form and practically as wide as their associated coating orifices, facilitate uniform dosing and distribution of the coating materials across the entire width of the strip to be coated. Therefore, the formation of the passages 76 and 82 for liquid of the nozzle of the invention as well as the additional "pre-plateaus" immediately promote the flow P1026 / 99MX uniform coating material with the opening of the associated switching bar. This significantly reduces the time necessary for the flow of the new coating material to reach or reach the stable operating state and, thereby, further reduces the production of waste. Another additional reason why the nozzle of the invention can achieve a rapid change between different coating compositions resides in the close separation between the manifolds 72 and 74, passages 76 and 82 of liquid and pre-plate 60. Due to this separation scale , essentially there is no dead space in which the unused coating material can be trapped or remain. In accordance with the foregoing, the dead time necessary to remove the solidified coating material from the nozzle is essentially eliminated. Another important feature of the applicator nozzle of the invention is that it is relatively maintenance free. This is mainly due to the elimination of leaks, which is due in turn to the adoption of several different design features as described above. For example, the little or little separation of the manifolds and the pre-plateau to the flow passages 76 and 82, reduces the dead spaces for P1026? 99MX the trapping of liquid coating material. In addition, the sealing system 110, as well as the end face sealing system described above, practically prevents the liquid coating material from being trapped between the lateral and end surfaces of the commutator bars and the mating surfaces of the associated sections. body of the mouthpiece, in which they are lodged. These particularities together allow the applicator nozzle 50 to cooperate in an essentially problem-free manner for extended periods of time, while at the same time allowing extremely fast changing between different coating liquids in a simple and easy manner. Figure 9 illustrates a preferred embodiment of the present invention, wherein the applicator nozzle 50 of the invention is provided with a cleaning system for cleaning the manifolds 72 and 74 as well as an automatic control system for controlling the operation of the nozzle switching and cleaning system. As shown in this figure, the first inlet 69 of the nozzle 50 is connected by suitable pipe to a source 132 of the first liquid coating material and to a source 134 of cleaning liquid. Control valves 136 and 138 are provided, connected to an automatic controller (not shown), to enable and P1026 / 99MX avoid the flow of the first liquid coating material and the cleaning liquid towards the inlet 69 as desired. The outer ends of the manifold 72 of the applicator nozzle 50 shown in Figure 9 are provided with outlet holes that are connected by suitable tubing to the waste discharge ports (not shown), the control valves 140 and 142 are provided. to allow and prevent the flow of fluid in manifold 72 out of these outlet ports, as desired. As shown in Figure 9, the second inlet port 70 is connected to a similar unit for supplying a second coating liquid and a cleaning liquid to manifold 74. During operation, the automatic control system causes the first actuators 86 of the applicator nozzle 50 opens the switch bar 80 as well as the control valve 136 to enable the first liquid coating material from the source 132 to flow into and through the nozzle 50 in the manner described above. When a change to the second coating liquid is desired, the automatic control system causes the first actuators 86 to move the switching bar 80, so that the P1026 / 99MX first passage 76 for liquid. Simultaneously, the automatic control system causes the second actuators 92 to move the switch bar 84 to open the second passage 82 for liquid. Essentially at the same time, the control valve 136 is closed to stop the flow of the first coating liquid towards the nozzle 50 and the flow of the second coating liquid towards the nozzle 50 starts upon opening the corresponding control valve connected to the source of the liquid. second coating liquid. Essentially at the same time, the cleaning system of the apparatus of the invention is operated to remove the liquid coating material from the manifold 72. This is done by the automatic control system when opening the control valves 138, 140 and 142. As a result, the fountain cleaning solution 134 flows into the manifold 72 from the first inlet 69 and then out of the manifold 72 from the two output ports located at their outer ends. After a suitable period of time, the flow of the cleaning solution is terminated by the automatic control system by closing the control valves 138, 140 and 142 to complete the cleaning operation. When it is desired to switch the operation of the applicator nozzle back to the first coating liquid, the above operation P1026 / 99MX is driven in the reverse direction, where manifold 74 will be cleaned while manifold 72 is in operating mode to supply the first coating liquid to the strip to be coated. A particular advantage of the applicator nozzle of the invention equipped with a cleaning system as illustrated in Figure 9, is that a much greater degree of flexibility than with the previous systems is possible. This is because a third coating liquid, different from the first and second, can be introduced into the nozzle channel that is not working after it has been cleaned and while the other nozzle channel is still running. In this way, it will be appreciated that the applicator nozzle of the invention, when equipped with a cleaning system such as that illustrated in Figure 9, can process three, four or, in fact, an unlimited number of different coating materials. without stopping between successive coating runs. Although in the foregoing only a few embodiments of the present invention have been described, it should be appreciated that many modifications can be made without departing from the spirit and scope of the invention. For example, the applicator nozzle of the invention can be provided with a heating element and / or channels for P-026 / -9 X receive and flow a thermal transfer fluid as well as an associated temperature control system to control the temperature of the liquid coating materials that will be processed in the nozzle. In addition, the nozzle control system can be installed to move the switching rods 80 and 82 at slightly different times, during each change, since this can have a beneficial effect or performance in certain cases. Also, the control system can be installed to allow both commutator bars to open or both to close at the same time. This would not only allow multiple layers of liquid coatings to be applied simultaneously, but would also facilitate cleaning and entrainment of the nozzle. It is intended that all these modifications be included within the scope of the present invention, which will be limited only by the following claims.

P1026 / 99MX

Claims (11)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A nozzle to deposit, alternately, multiple liquid materials on the surface of a moving band, to form a uniform layer of coating on it, the nozzle comprises: a nozzle body defining entry holes, first and second, an elongated hole for coating and passages for liquid, first and second communicating between the coating orifice and the liquid inlet orifices, first and second, respectively, and a closing means for alternately closing the first and second liquid passages, placed through the first and second passages for liquid; the closure means comprises at least two closure elements having at least one sliding surface mounted for reciprocating linear sliding movement at an angle with the first and second passages for liquid in the body of the nozzle, the closing element includes a sealing means on at least one sliding surface of the
2. P1025 / 99MX same to prevent liquid materials from leaking out of the nozzle. The nozzle according to claim 1, wherein the closing elements are switching rods arranged in a generally parallel manner to the covering orifice, the length of the switching rods is substantially the same as the length of the covering orifice.
3. 3. The nozzle according to claim 2, wherein the sealing means traverses the length of the commutator bars.
4. The nozzle according to claim 3, wherein the sealing means includes a first seal composed of at least one strip of compressible material.
5. 5. A nozzle for alternately depositing multiple liquid materials on the surface of a moving band to form a uniform layer of coating thereon, the nozzle comprising: a nozzle body defining entry holes, first and second, a elongated hole for coating and first and second passages for liquid communicating between the covering orifice and the first and second inlet orifices respectively and a closing means for alternatingly closing the first and second passages placed through the first and second passages.
6. P1026 / 99MX first and second passages comprising a first closing element for closing the first passage and a second closing element for closing the second passage, each of the closing elements will be slidably movable in the body of the nozzle and comprise: a switch bar generally arranged parallel to the elongated hole for coating, having a length substantially equal to the length of the elongated hole for coating and includes a sealing means comprising: at least one strip of flexible material running through the length of the switching bar on at least one slidable surface thereof to prevent liquid materials, first and second, from leaking out of the nozzle. The nozzle according to claim 5, wherein each commutator bar is constructed to be slidably movable between an open position and a closed position, each of the commutator bars having a primary seal composed of a first strip of compressible material, a secondary seal composed of a second strip of compressible material and a liquid seal between them. The nozzle according to claim 6, wherein each of the closure elements has two
7. P1026 -9MX main sliding surfaces substantially parallel to the cover hole, each of the main sliding surfaces is provided with primary, secondary and liquid seals that extend substantially the entire length of the switch bar.
8. 8. The nozzle according to claim 7, wherein at least the primary and secondary seals comprise a strip of flexible plastic or elastic material having a U-shaped cross section and a compressible strip carried within the enclosure formed by the U-shaped cross-section. The nozzle according to claim 1, wherein the closure element comprises commutator rods that can be slidably moved between an open position and a closed position, the commutator rods have at least one slidable surface, the slide surface is provided with a seal primary comprising a first strip of compressible material, a secondary seal comprising a second strip of compressible material and a seal between them. The nozzle according to claim 9, wherein the commutator rods are generally arranged parallel to the cover hole, the length of the commutator rods is substantially

   P1026 / -9MX same as the length of the covering hole and the switching bars have two sliding surfaces practically parallel to the covering hole, each of the sliding surfaces is provided with primary, secondary and liquid seals extending substantially all the way length of the commutator bars. The nozzle according to claim 10, wherein at least one of the primary and secondary seals comprises a strip of flexible plastic or elastic material having a U-shaped cross section and a compressible strip carried within the enclosure formed by the section transverse U-shaped

   P1026 / 99MX