Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
  • B05C5/02—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
  • B05C5/0254—Coating heads with slot-shaped outlet
  • B05C5/0258—Coating heads with slot-shaped outlet flow controlled, e.g. by a valve

Definitions

• the present invention relates to coating dies or applicator dies for applying a liquid coating material to a moving sheet or web.
• a coating die is used to apply a thin layer of liquid material (e.g., thermoplastic or solvent based) to a support substrate such as a sheet or film.
• a thin layer of liquid material e.g., thermoplastic or solvent based
• the most common coating process is to provide a continuous layer of coated material on the substrate by having a continuous stream of material applied to the moving substrate.
• the present disclosure relates to a coating apparatus and more particularly to a
• the coating die for intermittently applying liquid material onto a substrate.
• the coating die includes a shut-off bar located in the material flow channel within the die, the shut-off bar being activated (i.e., raised and lowered) using magnetic actuators which have fast acceleration and are highly accurate. Closing the shut-off bar stops the flow of coating material through and out of the die, thus interrupting the flow of coating material onto the substrate being coated.
• this invention is directed to a coating die having a die body with a flow channel therethrough, the flow channel in fluid communication with a die inlet and a die outlet.
• a shut-off bar in the die is moveable from an open position out of the flow channel to a closed position into the flow channel, the shut- off bar having an upstream surface, a downstream surface, and an end therebetween.
• the downstream surface physically contacts the flow channel
• the shut-off bar end makes no contact with the walls that define the flow channel.
• a flow channel wall may define a shoulder, so that when in the closed position, the downstream surface of the shut- off bar physically contacts the shoulder of the flow channel.
• the shut-off bar may move linearly from the open position out of the flow channel to the closed position in the flow channel.
• the shut-off bar may move orthogonally in relation to the flow channel, which may be vertically.
• the end of the shut-off bar may be slanted down from the upstream surface to the downstream surface.
• this invention is directed to a coating die having a die body with a flow channel therethrough, the flow channel in fluid communication with a die inlet and a die outlet, and with the flow channel defined by a first wall and an opposite second wall, the second wall defining a shoulder.
• the coating die includes a shut-off bar moveable from an open position out of the flow channel to a closed position into the flow channel, the shut-off bar having upstream surface and a downstream surface. When the shut-off bar is in the closed position, it extends across the flow channel and the downstream surface physically contacts the shoulder stopping flow through the flow channel.
• this invention is directed to a coating die having a die body with a flow channel therethrough, the flow channel in fluid communication with a die inlet and a die outlet.
• the die includes a shut-off bar moveable from a first position to a second position, so that when in the first position, the flow channel is open for flow of coating material therethrough and when in the second position, the flow channel is closed to flow of coating material therethrough.
• the seal formed by the shut-off bar is at a right angle to the flow channel.
• the shut-off bar may move at a right angle to the flow channel, for example, linearly from the first position to the second position in the flow channel.
• the shut-off bar may move orthogonally in relation to the flow channel, which may be vertically.
• FIG. 1 A is a schematic side view of a coating die apparatus for patch coating
• FIG. . IB is a schematic side view of another coating die apparatus for patch coating
• FIG. 2 is a perspective view of a coating die of the present disclosure
• FIG. 3 is a side view of the coating die of the present disclosure
• FIG. 4 is a side view of a shut-off bar
• FIG. 4A is an enlarged side view of the coating die of FIG. 3 illustrating the shut-off bar of FIG. 4 in a closed position
• FIG. 4B is an enlarged side view of the shut-off bar in an open position.
• the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise.
• the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
• the present disclosure relates to coating dies that have a shut-off bar positioned to stop the flow of coating material within the flow channel of the die when the shut- off bar is in the closed position. In the closed position, the shut-off bar extends across the material flow channel, blocking flow of coating material therethrough.
• the shut-off bar moves essentially transverse or orthogonal to the direction of material flow and the seal formed by the shut-off bar to block the flow is essentially transverse or orthogonal to the direction of material flow.
• the flow channel includes a shoulder against which the shut-off bar seals, the seal being essentially transverse or orthogonal to the direction of the material flow channel. Coating dies having a shut-off bar are particularly suited for patch coating applications.
• FIGS. 1 A and IB illustrate two generic processes for manufacturing continuous webs of patch coated material. Both processes include a coating die in accordance with the present disclosure that applies a coating material (for example, a thermoplastic material, solvent based, or a high-solids liquid material) to a moving substrate or web.
• a coating material for example, a thermoplastic material, solvent based, or a high-solids liquid material
• “length” refers to the dimension in the direction of travel of the substrate (i.e., the machine direction) past the coating outlet and "width” refers to the dimension taken transverse to the machine direction.
• FIG. 1 A a continuous sheet or web of substrate 5 is provided onto which regions of coating 6 are applied. Between regions of coating 6 are substrate regions void of coating 7. Coated regions 6 and void regions 7 are formed by coating die 10A applying the coating material in an intermittent manner; that is, coating die 10A starts, stops, and restarts the application of the coating material onto substrate 5 as substrate 5 passes by coating die 10A.
• Coating die 10A has a first or upper die body 12, a second or lower die body 14 and a flow channel 15 therebetween. Coating material passes through flow channel 15 from a coating material source (not illustrated), such as an extruder, to outlet 16 where the coating material is applied to substrate 5.
• coating die 10A deposits coated material on substrate 5 opposite a backup roll 9.
• the apparatus of FIG. 1 A which utilizes backup roll 9 opposite coating die 1 OA, is often referred to as "supported web" or "on-roll” coating.
• FIG. IB Similar to the process illustrated in FIG. 1 A, in FIG. IB a continuous sheet or web of substrate 5 is provided onto which regions of coating 6 are applied. Between regions of coating 6 are substrate regions void of coating 7. Coated regions 6 and void regions 7 are formed by coating die 10B applying the coating material in an intermittent manner; that is, coating die 10B starts, stops and restarts the application of the coating material onto substrate 5 as substrate 5 passes by coating die 10B.
• Coating die 10B has a first or upper die body 12, a second or lower die body 14 and a flow channel 15 therebetween. Coating material passes through flow channel 15 from a coating material source (not illustrated), such as an extruder, to outlet 16 where the coating material is applied to substrate 5.
• the apparatus of FIG. IB is often referred to as "tension web" coating or "off-roll” coating.
• coated regions 6 are eventually dried or cured, resulting in an elongate product having patches of coated regions 6 extending in the machine direction or direction of substrate 5 with regions void of coating 7 between adjacent coated regions 6.
• Coating processes such as illustrated in FIGS. 1 A and IB can operate at a wide range of production speeds. For example, it is not uncommon for commercial embodiments of the above arrangement to operate at rates from a few feet per minute (a meter or so per minute) to 3500 feet per minute (about 1070 meters per minute) using webs having widths of less than one foot, one meter, or more. It is understood that substrates of almost any length and/or width can be used with these coating processes. Although in most embodiments the substrate being coated is a flexible substrate such as a polymeric film, rigid substrates may also be coated with the dies and processes described herein.
• the coating material may be, for example, hot melt or thermoplastic materials (e.g., adhesives), solvent-based materials, low VOC-based materials, emulsion-based adhesives, and high-solids materials.
• hot melt or thermoplastic materials e.g., adhesives
• solvent-based materials e.g., solvent-based materials
• low VOC-based materials emulsion-based adhesives
• high-solids materials e.g., a wide variety of different liquid coatings, such as pressure sensitive adhesives, conductive coatings, insulating or non-conductive coatings, and inks
• Two applications that are particularly conducive to patch coating are formation of battery cells (e.g., lithium ion batteries) and solar panel or photovoltaic parts.
• alternating coated regions 6 and regions void of coating 7 are produced by a coating die according to this disclosure that has an internal shut-off bar that is actuated to interrupt the flow of coating material through the die.
• a coating die 100 has a general overall configuration that is well known, having a first or upper die body 102 and a mating second or lower die body 104. Die bodies 102, 104 define therebetween a flow channel 105 for passage of coating material through die 100. Coating material enters die at an inlet (not illustrated) and exits via outlet 106; in the Figures, the inlet is located at the right side of the illustration and outlet 106 is on the left side, so that coating material flows through channel 105 from right to left.
• Flow channel 105 is generically referred to herein and is not described in detail. Those skilled in the art of coating dies and coating processes understand that flow channel 105 includes a manifold downstream of the inlet, the manifold being for distributing the coating material across the width of the die.
• the manifold may be any suitable type, such as a horseshoe or Winter manifold, a coat hanger manifold, a fishtail manifold, or a t-manifold, and does not affect the inventive features of die 100. Downstream of the manifold may be a preland region prior to a land region that leads to outlet 106.
• Flow channel 105 may include other features, such as transition areas or run-out areas.
• Coating die 100 includes an internal shut-off bar that is used to interrupt the flow of coating material in flow channel 105 through die 100.
• a shut- off bar 110 for die 100 includes a blade 112 that extends the width of at least outlet 106 and in most embodiments the width of die 100.
• Blade 112 defines an upstream surface 114 and a downstream surface 11 of shut-off bar 110.
• Blade 112 is sufficiently rigid to withstand the pressure of coating material pushing against it without deforming; as an example, a blade 112 about 0.1 inch (about 2.5 mm) to 0.25 inch (about 6.3 mm) thick is able to withstand fluid pressures on the order of 28 psi (about 2 kg-force/cm 2 ), although both higher and lower pressures may be encountered on blade 112, depending on the pressure of the coating material entering die 100 and the time duration shut-off bar 110 is closed.
• a thinner blade 112 is preferred over a thicker blade 112, as a thinner blade will require less actuator force to overcome the fluid pressure pushing back up against blade 112 and its end 115 as it is lowered.
• Blade 112 has an end 1 15 between upstream surface 114 and downstream surface
• end 115 is an angled or slanted end, sloping down from upstream surface 114 to downstream surface 116. Benefits of a slanted end 115 are described below.
• a portion of shut-off bar 110 is moveable into and out from flow channel 105 to interrupt the flow of coating material therethrough.
• FIGS. 4 A and 4B illustrate shut-off bar 110 in a closed and an open position
• shut-off bar 110 moves in a direction essentially transverse or orthogonal to flow channel 105 and to the material flowing within channel 105.
• shut-off bar 110 moves essentially vertically, and in preferred embodiments moves exactly vertically and in a linear motion.
• FIG. 4A shut-off bar 110 extends into flow channel 105 and creates a dam across flow channel 105 to inhibit (and preferably completely stop) the flow of coating material through flow channel 105.
• FIG. 4B shut-off bar 110 is retracted at least partially out and preferably completely out from flow channel 105 and thus allows coating material to flow through flow channel 105.
• channel 105 has a topography that is not constant along its length.
• One skilled in the art of coating die design is able to readily determine the specific topography of flow channel 105, both of upper wall 122 and lower wall 124, needed to obtain the desired coating characteristics for the coating process.
• both upper wall 122 of channel 105 and lower wall 124 of channel 105 are not level, so that the height of flow channel 105, measured between upper wall 122 and lower wall 124, varies along the length of flow channel 105.
• the elevation of lower wall 124 deviates more than that of upper wall 122 does.
• the topography of flow channel 105 includes an upstream necked region 126, an enlarged region 127 and a downstream necked region 128, with shut-off bar 110 positioned to extend into channel 105 proximate to the transition from enlarged region 127 to downstream necked region 128.
• the transition between enlarged region 127 and downstream necked region 128 is defined by a shoulder 130 (see FIG. 4B).
• shut-off bar 110 is located downstream from the manifold portion of flow channel 105. In some designs, shut-off bar 110 is within the portion of flow channel 105 that is considered the preland region, upstream of the land region. In other designs, shut-off bar 110 is within the portion of flow channel 105 that is a transition region upstream of the preland region.
• shut-off bar 110 when in the extended or closed position, shut-off bar 110 is in close proximity to and preferably abuts shoulder 130.
• the flow of coating material through flow channel 105 in this embodiment, is from right to left, so that downstream surface 116 of shut-off bar 110 physically contacts and provides a seal with shoulder 130.
• the physical contact between shut-off bar 110 and shoulder 130, transverse to the flow direction of material in flow channel 105, provides a more secure and leak-free seal than would a seal that extends in the flow direction of material in flow channel 105, such as a seal between end 115 of shut-off bar 110 and lower wall 124.
• shut-off bar 110 does not “bottom out” (i.e., end 115 does not contact lower wall 124).
• various seals 132, 133 may be present.
• shut-off bar 110 In addition to the transverse physical contact between shoulder 130 and shut-off bar 110, the fluid pressure of the coating material dammed by closed shut-off bar 110 pushes against upstream surface 114 of shut-off bar 110, further increasing the contact and seal between shoulder 130 and downstream surface 116 of shut-off bar 110. To allow flow of coating material through flow channel 105, shut-off bar 110 is retracted or opened, as illustrated in FIG. 4B.
• shut-off bar 110 One benefit of having an angled, slanted or sloped end 115 of shut-off bar 110 can be seen in FIG. 4B.
• the slanted end 115 In the open, retracted position (FIG. 4B), the slanted end 115 creates a smooth transition in upper wall 122 between the enlarged region 127 of flow channel 105 and necked region 128, which provides a smoother fluid flow past shut-off bar 110.
• the pressure drop distribution through the area where shut-off bar 110 is located can be easily calculated and designed when the upper wall 122 has a smooth transition. Having the slanted or sloped end 115 also decreases the force needed to overcome the fluid pressure pushing back up against blade 112 as t is lowered.
• Another benefit of having a slanted or sloped end 115 is that the sloped end 115 can be angled backwards, to push coating fluid back towards the die inlet.
• shut-off bar 110 moves in a direction essentially transverse or orthogonal to flow channel 105 and to the material flowing within channel 105.
• shut-off bar 110 moves essentially vertically, and in preferred embodiments moves exactly vertically.
• Shut-off bar 110 can be actuated by any suitable magnetic, pneumatic, hydraulic, or mechanical means, although a magnetic actuator is preferred because of the fast acceleration and high accuracy.
• Some magnetic actuators are capable of the following features: travel distance 0.01 to 2 inches (about 0.025 to 5 cm); acceleration 0.1 to 20 G's (about 3.5 to 706 km/hr-second); peak force 0.3 to 300 lbs (about 0.136 to 136 kg); continuous force 0.1 to 100 lbs (about 0.045 to 45 kg); and resolution 0.0005 to 0.000004 inches (about 0.127 to 0.0013272 mm).
• a suitable magnetic actuator is a Voice Coil Positioning Stage, such as available from H2W Technologies, Inc. of Valencia, California. The Voice Coil Positioning Stage is particularly suited for short stroke lengths where intricate position, velocity and acceleration control is necessary.
• a plurality of actuators 140 is usually spaced along the length of shut-off bar 110, although in some embodiments, a single actuator 140 may be sufficient.
• FIG. 2 illustrates three actuators 140.
• actuators 140 may be manually controlled, for precision coating it is preferred that actuators 140 are computer controlled.
• a pressure relief valve and/or a material by-pass valve may be present in flow channel 105, close to the die inlet, usually upstream of the manifold.
• shut-off bar 110 opens and closes in, for example, one second or less, the build-up of back pressure on upstream surface 114 of blade 112 is minimal.
• the back pressure will be much higher, due to the accumulation of stopped coating material.
• a pressure relief valve and/or by-pass valve in fluid communication with flow channel 105 can be included to release undesired pressure from flow channel 105.
• the relief valve would be set at 30 psi (about 2.1 kg-f/cm 2 ) or slightly above 30 psi (about 2.1 kg-f/cm 2 ). If shut-off bar 110 is closed and the pressure starts to build up to undesired levels, the relief valve will open and by-pass fluid back to the die inlet, the coating material source, or to a reservoir. Maintaining a generally constant internal pressure results in a better coating.
• material to be coating is introduced to the inlet of die 100.
• a substrate such as a film substrate, is fed in position proximate outlet 106.
• Those skilled in the art of coating will be able to adjust the tension of the substrate and the distance between outlet 106 and the substrate to provide a proper coating on the substrate. Knowing the desired run speed (i.e., substrate speed), the desired length of coating (e.g., coated region 6) and the desired length of un-coated area (e.g., un-coated region 7) between coated areas, the duration of 'coating on' and 'coating off can be calculated, usually in seconds.
• shut-off bar 110 is extended or closed via actuator(s) 140, blocking the flow of coating material through flow channel 105.
• shut-off bar 110 is raised or opened, allowing coating material to again flow through channel 105 and out via outlet 106.
• die 100 can be used to form patch coatings on a substrate, each patch being 11.00 inches (about 28 cm) long (in the machine direction) and about 10 inches (25 cm) wide. Between adjacent patches is an uncoated region 0.787 inches (about 20 mm) long extending the width of the substrate. With the coating being done at 35 meters/minute, this requires coating material flowing for 2.09 seconds to form the patch and then the coating material flow being shut off for 0.03 second to form the uncoated region, after which the coating material again flows.

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• 2010
  • 2010-10-06 US US12/899,109 patent/US8992204B2/en not_active Expired - Fee Related
• 2011
  • 2011-10-05 JP JP2013532901A patent/JP5877841B2/ja not_active Expired - Fee Related
  • 2011-10-05 CN CN201180048772.7A patent/CN103153485B/zh not_active Expired - Fee Related
  • 2011-10-05 WO PCT/US2011/054867 patent/WO2012047963A2/en not_active Ceased

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