KR100359958B1 - Multiple Layer and Slide Die Coating Method and Apparatus - Google Patents

Abstract

The die coating method and apparatus of the present invention comprises an upstream bar (104, 154, 226) having an upstream lip, a central bar, a downstream bar (108, 158, 232) having a downstream lip and a vacuum bar (110, 160, 224). Having dies 100, 150, and 220. The upstream lip is formed as a land and the first manifold bar is formed as a sharp edge. The shape of the land coincides with the shape of the surface to be covered. Coating performance can be improved by changing at least one of slot height H, overbyte O and convergence angle C. The die may have slide surfaces 236 and 244, and the coating liquid flows out of the die from the passageway and slides along the slide surface to provide continuous coating beads between the sharp edges of the manifold bar, the upstream die lip, and the coated surface. Can be formed. The die may include several passageways for covering the multilayer.

Description

Multiple Layer and Slide Die Coating Method and Apparatus

<Technology field>

The present invention relates to a coating method. More specifically, the present invention relates to a coating method using a die.

Background

U.S. Patent No. 2,681,294 discloses a vacuum method for stabilizing coating beads in metered coating systems of direct extrusion and slide type. This stabilization enhances the coverage of these systems. However, these coating systems lack the overall capacity sufficient to provide a wet thin layer even at very low liquid viscosities required for some coated products.

US Pat. No. 2,761,791 teaches the simultaneous application of various liquids in separate layers on a moving web using various types of extrusion and slide coaters. However, these coating systems lack the overall performance sufficient to maintain the desired multiple wet layer thickness at the required web speed and coating gap for some coated products. U. S. Patent No. 5,256, 357 discloses a multi-layer coated die having an underbite at one corner of the slot. In some cases, underbytes in one of the two corners improve the sheathing environment.

U. S. Patent No. 4,445, 458 discloses an extruded bead-coated die having an inclined downward surface for applying interfacial forces to the downstream side of the coated beads and reducing the vacuum required to maintain the beads. Vacuum reduction minimizes cracked defects and coating marks. To improve the coating quality, the obtuse angle of the inclined plane with respect to the slot axis and the position along the slot axis of the oblique angle toward the moving web (overhang) and away from the moving web must be optimized. As a result of the optimization, the high quality required for coating of the photosensitive emulsion is obtained. However, the thin layer performance required for some coating products is lacking.

U. S. Patent No. 3,413, 143 discloses a two slot die with excess coating liquid pumped through the upstream slot into the coating bead zone. About half of the incoming liquid is pumped out of the bead zone through the downstream slots and the remainder is applied to the moving web. Excess liquid in the beads has a stabilizing effect and can improve performance without using a vacuum chamber. However, the device has a gap-to-wet thickness ratio of only a maximum of 3, which does not provide the performance required for some cladding products.

U.S. Patent No. 4,443,504 discloses a slide coating device in which the angle between the slide surface and the horizontal reference plane is in the range of 35 ° to 50 ° and the limited takeoff angle between the tangent to the coating roll and the slide surface is in the range of 85 ° to 100 °. It is starting. Operating within these ranges provides a compromise between performance from high fluid moments under the slide and coating uniformity from high liquid leveling forces on the slide surface. However, this system, even with a vacuum chamber, does not provide the performance required for some cladding products.

European patent application EP 552653 describes the shielding of the slide coating die surface adjacent to the coating beads, under the coating beads having a low energy fluorinated polyethylene surface. The shield range extends away from the coating beads starting at 0.05 to 5.00 mm below the coating lip tip. The low surface energy shield is separated from the clad lip tip by a bare metal strip. This causes the beads to be statically placed on the contact line. The low energy shield removes coating marks to facilitate die cleaning. The use of this in extrusion coated dies is not mentioned at all.

1 shows a known coating die 10 having a vacuum chamber 12 as part of a metered coating system. The coating liquid 14 is correctly supplied to the die 10 by the pump 16 and then applied to the moving web 18 supported by the backup roller 20. The coating liquid is supplied to the manifold 24 through the channel 22 and distributed in the coating on the slot 26 and the moving web 18 in the die. As shown in FIG. 2, the coating liquid passes through the slot 26 to form a continuous coating bead 28 between the upstream die lip 30, the downstream die lip 32, and the web 18. Dimensions (f ₁ ) and (f ₂ ), which are the widths of ribs 30 and 32, are typically in the range of 0.25 to 0.76 mm. Vacuum chamber 12 stabilizes the beads by applying a vacuum upstream of the beads. While this arrangement works well in many environments, die coating is required to improve the performance of known methods.

Summary of the Invention

The present invention is a die coating apparatus for coating a multilayer fluid coating on a surface. The apparatus includes a die having an upstream bar having an upstream lip, a wedge bar having a wedge edge and a downstream bar having a downstream lip. The upstream lips are formed as lands, the wedge edges are formed as sharp edges, and the downstream lips are also formed as sharp edges. The first passage passes through the die between the upstream bar and the wedge bar, and the second passage passes through the die between the wedge bar and the downstream bar. The first passageway has a first slot defined by the upstream lip and the wedge edge, and the second passageway has a second slot defined by the wedge edge and the downstream lip. The first coating liquid forms a continuous coating bead between the upstream die lip, the wedge edge and the coated surface for application on the surface to be coated out of the die from the first slot. The second coating liquid flows out of the die from the second slot to form a continuous coating bead between the wedge edge, the downstream die lip and the surface to be coated for application onto the first coating liquid. Even when the vacuum is increased, the beads do not move much into the space between the land to be coated and the land.

The shape of the land corresponds to the shape of the surface to be covered. If the surface is curved, the land is also curved. The die may also apply a vacuum upstream of the beads to stabilize the beads. The vacuum may be applied using a vacuum chamber having a land mounted vacuum bar. The shape of the vacuum land also matches the shape of the surface to be covered. Lands and vacuum lands can have the same bend radius and have the same or different convergence angles for the surface to be coated.

Changing at least one of slot height, overbite and convergence angle can improve coating performance. The slot height, overbite and convergence angle are selected in combination with each other, and the die between the tangent plane parallel to the line on the surface to be coated directly opposite the length of the land, the corner angle of the downstream bar, the sharp edge and the surface of the downstream bar of the covered slot. The attack angle and covering gap distance between the sharp edge and the surface to be covered are selected in combination with each other.

In another embodiment, the die includes an upstream bar having an upstream lip, a separator, and a downstream bar having a downstream lip. The upstream lip is formed as a land and the downstream lip is formed as a sharp edge. The first passage passes through the die between the upstream bar and the separator, and the second passage passes through the die between the separator and the downstream bar. The first and second passages combine to form a single slot defined by an upstream lip and a downstream lip. The two coating liquids are combined inside the die slots and flow through the slots as separate stacks to form the coating beads and transport to the surface to be coated.

The die coating method according to the present invention comprises the steps of passing a first coating liquid through a first slot; Passing the second coating liquid through the second slot; Forming a continuous coating bead with a first coating liquid between an upstream die lip, a wedge edge, and the surface being coated to apply on the surface being coated; And forming a continuous coating bead with a second coating liquid between the wedge edge, the downstream die lip, and the surface being coated for application onto the first coating liquid. Even during vacuum stretching, the beads do not move much into the space between the land and the surface to be coated.

The method also includes the length of the land, the corner angle of the downstream bar, the die attack angle between the tangent plane parallel to the line on the surface to be directly facing the sharp edge of the downstream lip and the downstream bar surface of the sheathing slot, and the sharp edge of the downstream lip. Selecting a coating gap distance between the edge and the surface to be coated in combination with each other; And selecting the slot height, the overbyte, and the convergence angle in combination with each other. The method may also include applying a vacuum upstream of the beads to stabilize the beads.

Another method includes passing the first coating liquid through the first passageway; Passing the second coating liquid through the second passageway; Combining the first and second coating liquids inside the die slot; Flowing the first and second coating liquids through the slots as separate stacks to form coating beads; And conveying the beads to the surface to be coated.

The present invention is a die coating apparatus for coating a fluid coating on a surface. The present arrangement includes an upstream bar with upstream lips, a manifold bar, a downstream bar with downstream lips, a vacuum bar and a die with a slide surface. The upstream lip is formed as a land and the first manifold bar is formed as a sharp edge. The first passageway passes through the die between the manifold bar and the downstream bar. The coating liquid flows out of the die from the passageway and slides along the slide surface to form continuous coating beads between the sharp edges of the manifold bars, the upstream die lips and the coated surface. Even during vacuum stretching, the beads do not move much into the space between the land and the surface to be coated. The shape of the land corresponds to the shape of the surface to be covered.

The present invention is also a multi-layer die coating apparatus for coating a multi-layered fluid coating on a surface. The apparatus includes an upstream bar having an upstream lip, a first manifold bar, a second manifold bar, a downstream bar having a downstream lip, a vacuum bar and a die having a slide surface. The upstream lip is formed as a land and the first manifold bar is formed as a sharp edge. The first passageway passes through a die between the first manifold bar and the second manifold bar. The first coating liquid flows out of the die from the first passageway and slides along the slide surface to form a continuous coating bead between the sharp edge of the manifold bar, the upstream die lip, and the coated surface for application on the surface to be coated. . The second passageway passes through the die between the second manifold bar and the downstream bar. The second coating liquid flows out of the die from the second passageway and slides along the slide surface to form a continuous coating bead between the sharp edges of the manifold bar, the upstream die lip and the coated surface for application on the first coating liquid.

The die coating method according to the present invention comprises the steps of passing the coating liquid through a passage defined by a manifold bar with sharp edges and a downstream bar with downstream lips; And sliding the coating liquid exiting the passage along the slide surface to form a continuous coating bead between the sharp edge of the manifold bar, the upstream die lip formed as a land, and the surface being coated. Even during vacuum stretching, the beads do not move much into the space between the land and the surface to be coated.

The method also includes selecting a combination of the length of the land, the corner angle of the first manifold bar and the covering gap distance between the sharp edge and the surface to be coated; And selecting the overbyte and the convergence angle in combination with each other.

The multi-layer coating method includes passing a first coating liquid through a first passageway defined by a first manifold bar and a second manifold bar formed as sharp edges; Sliding the first coating liquid flowing out of the first passage along the slide surface; Forming a continuous coating bead between the sharp edge of the manifold bar, the upstream die lip and the surface being coated to apply a first coating liquid onto the surface to be coated; Passing the second coating liquid through a second passageway defined by the second manifold bar and the downstream bar; Sliding a second coating liquid flowing out of the second passage along the slide surface; And forming a continuous coating bead between the sharp edge of the manifold bar, the upstream die lip and the surface being coated to apply the second coating liquid onto the first coating liquid.

<Detailed Description of the Invention>

The present invention is a die coating method and apparatus that includes sharp edges and lands arranged to improve and optimize performance. Lands are arranged to conform to the shape of the surface in the direct coating solution application zone. Lands can be bent to fit the web passing around the backup roller or flat to fit the free span of the web between the rollers.

3 shows an extrusion die 40 with a vacuum chamber 42 of the present invention. The coating liquid 14 is supplied to the die 40 by the pump 46 and then applied to the moving web 48 supported by the backup roller 50. The coating liquid is supplied to the manifold 54 through the channel 52 and distributed in the coating on the slot 56 and the moving web 48. As shown in FIG. 4, the coating liquid 14 passes through the slot 56 to form a continuous coating bead 58 between the upstream die lip 60, the downstream die lip 62, and the web 48. do. The coating liquid may be one of various liquids or other fluids. The upstream die lip 60 is part of the upstream bar 64 and the downstream die lip 62 is part of the downstream bar 66. The height of the slots 56 may not be adjusted or decked by the U-shaped shims, which may be made of brass or stainless steel. Vacuum chamber 42 stabilizes the coated beads by applying a vacuum upstream of the beads.

As shown in FIG. 5, the upstream lip 60 is formed as a curved land 68, and the downstream lip 62 is formed as a sharp edge 70. This arrangement improves the overall performance over known die type coaters. Improved performance means that it can work at increased web speeds and coating gaps, at higher coating liquid viscosities, and to produce wet coat layers at thinner thicknesses.

The sharp edge 70 should be clean, free of nicks and cuts, and straight within 1 micron of 25 cm in length. The corner radius should be less than 10 microns. The radius of the curved land 68 should be equal to the radius of the backup roller 50 plus a minimum non-critical 0.13 mm tolerance for the coating gap and web thickness. Alternatively, the radius of curved land 68 may exceed the radius of backup roller 50, and the shims may be used to orient the land with respect to web 48. Even if the radius of the land is larger than that of the backup roller, by operating the land with the shims, the predetermined convergence angle C achieved by the land having the same radius as the backup roller 50 can be achieved.

5 also shows the dimensions of the geometrical operating parameters for monolayer extrusion. The length L ₁ of the curved land 68 on the upstream bar 64 may range from 1.6 mm to 25.4 mm. Preferred length L ₁ is 12.7 mm. The corner angle A ₁ of the downstream bar 66 may range from 20 ° to 75 °, preferably 60 °. The corner radius of the sharp edge 70 should be about 2 microns to about 4 microns, preferably less than 10 microns. The die attack angle A ₂ between the surface of the bar 66 downstream of the sheath slot 56 and the contact plane P parallel to the line on the surface of the web 48 directly opposite the sharp edge 70 ranges from 60 ° to 120 °. And preferably 90 ° to 95 °, such as 93 °. The covering gap G ₁ is the vertical distance between the sharp edge 70 and the web 48. (The coating gap G ₁ is measured at sharp edges, but in some drawings it has been spaced away from the sharp edges for clarity. Regardless of the G ₁ position shown in the drawing, The gap is increased.) The gap is measured at the sharp edge.)

Slot height H may range from 0.076 mm to 3.175 mm. The overbite O is the sharp edge of the downstream bar 66 in the direction toward the web 48 in the direction toward the web 48 at the downstream edge 72 of the curved land 68 on the upstream bar 64. 70). The overbite can also be seen in any given covering gap G _{1 such} that the downstream edge 72 of the curved land 68 is away from the web 48 with respect to the sharp edge 70. The overbite can range from 0 mm to 0.51 mm and should be set within 2.5 microns of each other at the opposite end of the die slot. For such a coating system, for example, a precise installation system is required to achieve precise overbite uniformity. Convergence angle C is the counterclockwise angle of the bent lands 68 spaced apart at a position parallel to (or concentric) the web 48 with the downstream edge 72 as the center of rotation, as shown in FIG. to be. The convergence angle can range from 0 ° to 2.29 °, with the opposite ends of the die slots being set within 0.023 ° of each other. Slot height, overbite and convergence angle as well as fluid properties such as viscosity affect the performance and method of the die sheathing apparatus.

In terms of overall performance, for liquids with a viscosity of 1,000 centipoise (cp) or less, it is preferred that the slot height is 0.18 mm, the overbite is 0.076 mm, and the convergence angle is 0.57 °. Different slot heights can result in nearly identical performance levels. Performance benefits can also be found when the viscosity exceeds 1,000 centipoise. Keeping the convergence angle at 0.57 °, the optimal combination of several different slot heights and overbytes is as follows:

Slot height overbyte

0.15 mm 0.071 mm

0.20 mm 0.082 mm

0.31 mm 0.100 mm

0.51 mm 0.130 mm

In the above-described liquid viscosity, the optimal overbyte value at any given convergence angle appears to be directly proportional to the square root of the slot height value. Similarly, the optimal appropriate overbyte value of any given slot height value appears to be inversely proportional to the square root of the convergence angle.

As shown in FIG. 6, the vacuum chamber 42 may be integral to or secured to the upstream bar 64 to allow precise and repeatable vacuum gas flow. Vacuum chamber 42 may be formed using vacuum bar 74 and may be connected to vacuum source channel 80 through optional vacuum limiter 76 and vacuum manifold 78. The curved vacuum land 82 can be an integral part of the upstream bar 64 or a portion of the vacuum bar 74 that is secured to the upstream bar 64. The vacuum land 82 has the same bend radius as the bent land 68. The curved lands 68 and vacuum lands 82 may be polished together to be "side by side" with each other. In this case, the vacuum lands 82 and curved lands 68 have the same convergence angle C relative to the web 48.

The vacuum land gap G ₂ is the distance between the vacuum land 82 and the web 48 at the bottom of the vacuum land, and the sum of the displacements due to the covering gap G ₁ , the overbyte O, and the convergence angle C of the curved land 68. (Unlike the G ₁ position shown in the figure, the gap is the vertical distance between the bottom of the vacuum land and the web). If the vacuum land gap G ₂ is large, ambient air flows into the vacuum chamber 42. Although the vacuum source may have a capacity sufficient to replenish a certain vacuum pressure level in the vacuum chamber 42, the coating performance may be degraded when air is introduced.

In FIG. 7, the vacuum land 82 is part of the vacuum bar 74 attached to the upstream bar 64. During fabrication, the curved land 68 is finished with a "grounded" convergence angle C. The vacuum bar 74 is then joined, the vacuum land 82 is finish polished using different polishing centers such that the vacuum land 82 is parallel to the web 48, and the vacuum land gap G ₂ is the desired overbyte value. Is equal to the coating gap G ₁ when set. The vacuum land length L ₂ may range from 6.35 mm to 25.4 mm. Preferred length L ₂ is 12.7 mm. This embodiment has a greater overall coating performance in a more difficult coating environment than the embodiment of FIG. 6, but always finish polished under certain operating conditions. Thus, the vacuum land gap G ₂ may be far from its optimum value since the covering gap G ₁ or the overbite O changes.

8 and 9, the upstream bar 64 of the die 40 is mounted on the upstream bar deployer 84, and the vacuum bar 74 is mounted on the vacuum bar deployer 86. The curved land 68 on the upstream bar 64 and the vacuum land 82 on the vacuum bar 74 are not directly connected to each other. The vacuum chamber 42 is connected to its vacuum source via a vacuum bar 74 and a placer 86. Mounting and placing on the vacuum bar 74 is separate from mounting and placing on the upstream bar 64. This improves die performance and enables precise and repeatable vacuum system airflow. The firm arrangement of the vacuum bar system also helps to improve performance compared to known systems. In addition, this arrangement for the vacuum bar 74 can improve the performance of other known coaters such as slots, extrusion and slide coaters. The flexible vacuum seal strip 88 seals between the upstream bar 64 and the vacuum bar 74.

The gap G ₂ between the vacuum land 82 and the web 48 is not affected by the change in the coating gap G ₁ , the overbite O or the convergence angle C, and can keep its optimum value during the coating process. The vacuum land gap G ₂ may be set in the range of 0.076 mm to 0.508 mm. Preferred gap G ₂ values are 0.15 mm. Each position of the preferred vacuum lands 82 is parallel to the web 48.

During the coating process, the vacuum level is adjusted to produce the highest quality coating layer. Typical vacuum levels are 51 mmH ₂ O when the coating liquid having a viscosity of 2 centipoise is coated with a wet layer thickness of 6 microns and a web speed of 30.5 m / min. In the case of reduced wet layer thickness, increased viscosity or increased web speed, higher vacuum levels than 150 mmH ₂ O may be required. The dies of the present invention have lower satisfactory minimum vacuum levels and higher satisfactory maximum vacuum levels than known systems, and may operate at zero vacuum levels that are not possible with known systems in some circumstances.

10A and 10B show some batch adjustments and vacuum chamber closure. Adjusting the overbite, the downstream bar 66 against the upstream bar 64 such that the sharp edge 70 moves toward or away from the web 48 relative to the downstream edge 72 of the curved land 68. Are translated. Adjusting the convergence angle, the upstream bar 64 and around the axis passing through the downstream edge 72 such that the curved land 68 moves away from or parallel to the web 48 from the position shown in FIG. The downstream bars 66 rotate together. Adjusting the sheath gap causes the upstream bar 64 and the downstream bar 66 to translate together to change the distance between the sharp edge 70 and the web 48, and the vacuum bar stops on its mount 86. And the vacuum sealing strip 88 is bent to prevent air leakage during adjustment. Air leakage from the die end to the vacuum chamber 42 is minimized by an end plate 90 attached to the end of the vacuum bar 74 that overlaps the end of the upstream bar 64. The vacuum bar 74 is 0.10 mm to 0.15 mm longer than the upstream bar 64 such that the clearance between each end plate 90 and the upstream bar 64 in the central state ranges from 0.050 mm to 0.075 mm.

One unexpected operating characteristic was observed during the coating process. In other words, even during the vacuum increase, the beads do not move much into the space between the curved land 68 and the moving web 48. This allows higher vacuum levels to be used than the vacuum levels possible with the use of known extrusion coaters and provides a correspondingly high level of performance. The present invention shows improved performance over known systems even when little or no vacuum is required. The fact that the beads do not move very much into the space between the curved land 68 and the web 48 is also different in the "runout" effect of the backup roller 50 on the downstream coating weight than in the case of known extrusion coaters. It means not.

11 is a graph of coating test results comparing the performance of a known extrusion die to the extrusion die of the present invention. In this test, the coating liquid of viscosity 1.8 centipoise containing an organic solvent was apply | coated to the flat polyester film web. The performance standard was the minimum wet layer thickness at four different coating gap levels for each of the two coating systems in the speed range of 15 to 60 m / min. Curves A, B, C and D were performed with known gaps of 0.254 mm, 0.203 mm, 0.152 mm and 0.127 mm using known conventional dies, respectively. Curves E, F, G and H each use a die according to the invention in the same covering gap. Compared with conventional dies, it is easily identified that the wet thickness according to the invention is lower. 12 shows comparative test results for similar coating liquids with a viscosity of 2.7 centipoise in the same coating gap. Again, the performance benefits of the present invention are clearly identified.

FIG. 13 summarizes data obtained from coating tests in which a liquid having seven different viscosities and containing different organic solvents was applied to a flat polyester film web. This result compares the performance of the conventional extrusion coating machine (conventional product) and this invention (invention product). Mix performance standards. The performance advantages of the present invention can be found at web speed (Vw), wet layer thickness (Tw), coating gap, vacuum level, or a combination thereof.

One measure of coater performance is the ratio (G / Tw) of the coating gap to the wet layer thickness for a particular coating liquid and web speed. 14 shows a series of constant G / Tw lines and viscosity values of the extrusion die of the present invention for nine different coating liquids. The liquid was coated on a flat polyester film substrate at a web speed of 30.5 m / min. Several viscosity values appear disordered due to the effects of other coverage factors. Four additional performance lines were added after calculating the G / Tw values for the web speed of 30.5 m / min from FIGS. 11 and 12. From top to bottom, the performance solid line is G / Tw for a liquid of 2.7 centipoise and 1.8 centipoise coated by a known extrusion die and 2.7 centipoise and 1.8 centipoise coated by the extrusion die of the present invention. Is the G / Tw of the liquid. The line for performance of the present invention has a larger G / Tw value than the line for performance of conventional clad dies. In addition, the lines for the present invention approximate constant G / Tw lines of 18.8 and 16.8 on average, respectively. The line of the known coater indicates that the G / Tw variation is significantly larger over its entire length. The present invention further improved the operating characteristics for coating bead retention with lower wet thickness values than known systems.

15 and 16 show a multilayer extrusion die 100 having a vacuum chamber 102 of the present invention. Die 100 includes an upstream bar 104, a wedge bar 106, and a downstream bar 108. Vacuum pressure for the vacuum chamber 102 is supplied through the vacuum bar 110. Upstream bar 104 is mounted on upstream bar deployer 112, and vacuum bar 110 is supported by vacuum bar deployer 114. The first coating liquid 116 is supplied to the first manifold 120 through the first channel 118 and distributed through the first slot 122 to form a first wet coating layer on the web 48. The second coating liquid 124 is supplied to the second manifold 128 through the second channel 126 and distributed through the second slot 130 to form a second wet coating layer on the first coating layer. Both liquids are combined in the coating beads 132.

Alternatively, a second channel 126 can be formed in the wedge bar 106. In addition, channels (not shown) may be formed to intersect through die 100, such as through wedge bar 106. The channel may receive cold or hot water or other fluid to cool or heat the die.

In this arrangement, two sharp edges, downstream edge 134 and wedge edge 136, may have overbite adjustment. Both flow slots 122 and 130 may each have a slot height adjustment. In some cases, it has been found that underbytes in either of these two corners can improve the multilayer coating environment. Both overbytes (toward the web 48) and underbytes (away from the web 48) of the two edges 134 and 136 are measured with respect to the downstream edge 138 of the curved land 140. The adjustment value for the sharp edge 134 on the downstream bar 108, moving along the cladding slot 130, may range from underbytes of 0.51 mm to overbytes of 0.51 mm. The adjustment value for the wedge edge 136 on the wedge bar 106, moving along the cladding slot 122, may range from underbytes of 0.51 mm to overbytes of 0.51 mm. The two slot heights H ₁ and H ₂ may range from 0.076 mm to 3.175 mm. If the convergence angle on the curved land 140 is set to 0.57 ° and the two slot heights are used at 0.254 mm, the preferred overbite value is 0.0 mm for the wedge edge 136 and downstream on the downstream bar 108. In the case of the edge 134 is an overbyte of 0.076 mm. The gap between vacuum land 142 and web 48 on vacuum bar 110 may range from 0.076 mm to 0.508 mm, but is preferably 0.15 mm. The flexible sealing strip 144 seals between the upstream bar 104 and the vacuum bar 110. The principle of this die can also be applied to multilayer dies for coating of three or more layers.

17 and 18 show another embodiment of a multilayer extrusion die 150 having a vacuum chamber 152. Die 150 includes an upstream bar 154, a slot shim 156, and a downstream bar 158. Vacuum pressure for the vacuum chamber 152 is supplied through the vacuum bar 160. Upstream bar 154 is mounted on upstream bar deployer 162, and vacuum bar 160 is supported by vacuum bar deployer 164. The first coating liquid 116 is supplied to the first manifold 168 through the first channel 166, and the second coating liquid 124 is supplied to the second manifold 172 through the second channel 170. do. Both coatings are combined in die 150 and flow through slot 174 as a separate stack. Coating liquids 116 and 124 pass through coating beads 176 to form two wet coating layers on web 48. Alternatively, a wedge bar may be used in place of slot shim 156 to separate two manifolds 168 and 172.

Only one sharp edge 178 on the downstream bar 158 is involved in the overbite adjustment of the downstream edge 180 of the curved land 182 on the upstream bar 154. The range of slot heights, overbytes and convergence angles is the same as specified in FIG. Preferably, the slot height is 0.18 mm, the overbite is 0.076 mm and the convergence angle is 0.57 °. The gap range between vacuum land 184 and web 48 on vacuum bar 160 is 0.076 mm to 0.508 mm, preferably 0.15 mm. The flexible sealing strip 186 prevents leakage between the upstream bar 154 and the vacuum bar 160.

19 shows a known slide coating die 200 using a vacuum chamber 202 having a liquid distribution manifold 204, a flow slot 206, and a slide surface 208. The coating liquid is coated on the web 18 passing around the backup roller 20. The cover bead edge 210 is a flat face 3.2 mm wide that extends across the die. The bead edge 210 is typically disposed along the backup roller radius line R at an angle A ₃ of 10 ° below horizontal to tilt the die slide surface 208 at an angle A ₄ of 25 ° below horizontal.

20 shows a multilayer slide sheath die 220 of the present invention having a conventional face angle using a vacuum chamber 222. Die 220 includes a vacuum bar 224, an upstream bar 226, a first manifold bar 228, a second manifold bar 230, and a downstream bar 232. The cover bead edge 238 is disposed along the backup roller radius line R at an angle A ₃ of 10 ° below horizontal to cause the die slide surface 236 to be inclined at an angle A ₄ of 25 ° below horizontal. The dimensions and positions of interest are bead edge angle A ₁ , overbite O, convergence angle C, sheath gap G ₁ and vacuum land gap G ₂ . There is no flow slot that feeds the coating liquid directly to the coating beads. The coating liquid flows down the slide surface 236 and flows over the bead edge 238. This slide coating die exhibits improved performance over known slide coating machines. The bead edge angle A ₁ may range from 50 ° to 90 °. Preferred bead edge A ₁ is 80 °. When the convergence angle C is set to 0.57 °, the preferred overbyte O is 0.076 mm. In operation, the first coating liquid 116 passes through the coating beads through the first slot 240 and down the slide surface 236 to form a first layer on the web 48. The second coating liquid 124 passes through the coating beads through the second slot 242 and over the first coating liquid on the slide surface 236 below the slide surface 244 to form a second layer on the first layer. .

21 shows a combination extrusion and slide coater 250 of the present invention that can be used with a combination extrusion and slide coater of multiple or single layers. Coater 250 includes a vacuum bar 224, an upstream bar 226, a first manifold bar 228, a second manifold bar 230, and a downstream bar 232. The bead edge 238 is disposed along the backup roller radius line R at an angle A ₃ of 10 degrees below horizontal so that the die slide surface 236 is inclined at an angle A ₄ of 25 degrees below horizontal. Alternatively, the bead edge 238 can be arranged such that fluid flowing out of the first slot 252 is perpendicular to the web 48 at the point of application.

The dimensions and locations of interest are bead edge angle A ₁ , first slot 252 height, overbite O, convergence angle C, sheath gap G ₁ and vacuum land gap G ₂ . Preferred bead corner angle A ₁ is 80 °. When the convergence angle C is set to 0.57 ° and the first slot 252 height is used at 0.15 mm, the preferred overbyte is 0.076 mm. The first coating liquid 116 passes through the coating beads through the first slot 252 to form a first coating layer on the web 48. The second coating liquid 124 passes through the coating beads through the second slot 254 below the slide surface 236 to form a second coating layer on the first layer. The third coating liquid 256 passes through the bead through the third slot 258 and below the slide surface 244 over the second coating liquid 124 on the slide surface 236 to form a third layer on the second layer. Form.

FIG. 22 shows the slide coating die of the present invention using a plane angle that is more inclined than is possible with known systems. The die 310 is disposed by the sheathing bead edge along the radial line R at an angle A ₃ in the range 35 ° to 90 ° above horizontal, preferably 45 °. The slide surface 312 is present at an angle A ₆ in the range of 30 ° to 75 °, preferably 55 ° from the tangent plane P to the backup roller 314. This places the slide surface 312 at an angle A ₇ of 10 ° from the vertical. The coating liquid is pumped through the inlet channel 316 to the manifold 318 and through the coating slot 320 below the slide surface 312 to be coated on the web 48. Bead stability is provided by the vacuum chamber 324 in which the vacuum bar 326 is mounted and adjusted separately from the upstream bar support 328. The slide surface length L can be variously selected according to the coating liquid rheology and flow rate to obtain a smooth and flawless coating. Slide surface length L may range from 1.6 mm to 50.8 mm. Liquids with a viscosity of less than 10 centipoise move better at slide lengths of 12.7 mm or less. Liquids whose viscosity exceeds about 10 centipoise move better at lengths greater than 12.7 mm.

In one example, the slide surface length was 38.1 mm, the overbite was 0.076 mm, and the convergence angle was 0.38 °. A coating liquid having a viscosity of 100 centipoise was coated on aluminum foil at a web speed of 15.2 m / min. The vacuum was 63.5 mmH ₂ O, the coating gap was 0.508 mm and the wet layer thickness was 0.027 mm (G / Tw = 18.8). The coating was smooth and flawless.

FIG. 23 shows a multilayer version of the die of FIG. 22. FIG. 24 shows a multilayer combination extrusion and slide version of the die of FIG. 22. The overbyte and convergence angle are as described above. In both cases the preferred corner angle A ₁ is 80 °.

1 is a schematic cross-sectional view of a known coating die.

FIG. 2 is an enlarged cross-sectional view of the slot and lip of the die of FIG. 1. FIG.

3 is a cross-sectional view of the extrusion die of the present invention.

4 is an enlarged cross-sectional view of the slot and lip of the die of FIG.

5 is a cross-sectional view of a slot and a lip similar to FIG. 4.

6 is a cross-sectional view of an alternate vacuum chamber arrangement.

7 is a cross-sectional view of another alternative vacuum chamber arrangement.

8 is a cross-sectional view of an alternative extrusion die of the present invention.

9A and 9B are enlarged cross-sectional views of the slot, face, and vacuum chamber of the die of FIG. 8.

10A and 10B are schematic views of the die of FIG. 8.

11 shows coating test results comparing the performance of known extrusion dies and extrusion dies of the present invention for coating liquids having a viscosity of 1.8 centipoise.

12 shows the comparative test results for the coating liquid having a viscosity of 2.7 centipoise.

Figure 13 summarizes the data obtained as a result of the coating test.

14 is a graph of a constant G / Tw line of the extrusion coating die of the present invention for nine different coating liquids.

15 is a cross-sectional view of a multilayer extrusion die in accordance with the present invention.

FIG. 16 is a cross sectional view of the vacuum chamber and the face of the die of FIG. 15; FIG.

17 is a cross-sectional view of another embodiment of a multilayer extrusion die.

18 is a cross-sectional view of the vacuum chamber and the face of the die of FIG. 17.

19 is a sectional view of a known slide coating die.

20 is a cross-sectional view of the multilayer slide coating die of the present invention.

21 is a cross sectional view of a multi-layer combined extrusion and slide coater of the present invention.

22 is a cross-sectional view of a die according to another embodiment of the present invention.

FIG. 23 is a cross-sectional view of the multilayer version of the die of FIG. 22.

FIG. 24 is a cross-sectional view of a multi-layer combined extrusion and slide version of the die of FIG. 22.

Claims (11)

A die 100 comprising an upstream bar 104 having an upstream lip, a wedge bar 106 having a wedge edge and a downstream bar 108 having a downstream lip, wherein the upstream lip is formed as a land 140, The wedge edge is formed as a sharp edge 136 and is no further from the surface than the corner of the adjacent land, the downstream lip is formed as a sharp edge 134], and the die between the upstream bar 104 and the wedge bar 106. First passage 118 through 100 and second passage 126 through die 100 between wedge bar 106 and downstream bar 108, where the first passage 118 is upstream. A first slot 122 defined by a lip and wedge edge, and a second passageway 126 includes a second slot 130 defined by a wedge edge and a downstream lip; 116 is applied on the surface that flows out of die 100 through first slot 122 and is coated. To form a continuous coating bead 132 between the upstream die lip, wedge edges and the surface being coated, and the second coating liquid 124 flows out of the die 100 through the second slot 130 and is first A multi-layer die coating apparatus for coating a multi-layered fluid coating on a surface, forming a continuous coating bead 132 between the wedge edge, the downstream die lip, and the surface being coated for application onto the coating liquid. The method of claim 1, Vary one or more of slot height H, overbyte O, and convergence angle C, select slot height, overbyte and convergence angle in combination with each other, length L of land 140, corner angle of downstream bar 108 A ₁ , die attack angle A ₂ between the tangent plane parallel to the line on the surface to be directly facing the sharp edge 134 and the surface of the downstream bar of the covering slot, and the coating gap between the sharp edge 134 and the surface to be coated. And means for improving the coating performance by selecting the distance G in combination with each other. The method according to claim 1 or 2, And a slide surface (236) and (244) on which at least one of the coating liquid layers slides. A die 220 comprising an upstream bar 226 with an upstream lip, a manifold bar 228, a downstream bar 232 with a downstream lip, a vacuum bar 224 and a slide surface 236, wherein the upstream lip is Formed as a land, and the first manifold bar 228 is formed as a sharp edge 238 adjacent the surface], and a first passageway through the die 220 between the manifold bar 228 and the downstream bar 232. Wherein the coating liquid flows out of the passageway from the die 220 and slides along the slide surface 236 to form a continuous coating bead between the sharp edge 238 of the manifold bar, the upstream die lip, and the coated surface, Die device for coating a fluid coating on a surface. The method according to any one of claims 1, 2 or 4, A die coating apparatus in which the shape of the land matches the shape of the surface to be covered. The upstream lip passes the first coating liquid 116 through a first slot 122 defined by an upstream bar 104 having an upstream lip and a wedge bar 106 having a wedge edge, wherein the upstream lip is a land 140. And wedge edges are formed as sharp edges 136; Passing the second coating liquid 124 through a second slot 130 defined by a wedge bar 106 and a downstream bar 108 having a downstream lip, where the downstream lip is formed as a sharp edge 134. step; Forming a continuous coating bead 132 with the first coating liquid 116 between the upstream die lip, the wedge edge and the coated surface for application on the coated surface; And forming a continuous coating bead 132 with a second coating liquid 124 between the wedge edge, the downstream die lip, and the surface being coated for application onto the first coating liquid. Method of die coating on a phase. The method of claim 6, The length of the land L, the corner angle A ₁ of the downstream bar, the die attack angle A ₂ between the tangent plane parallel to the line on the surface to be directly opposite the sharp edge of the downstream lip and the surface of the downstream bar of the sheath slot, and the sharp edge Selecting a coating gap distance G between the surfaces to be coated in combination with each other; And selecting the slot height H, the overbyte O, and the convergence angle C in combination with each other. The method of claim 6, Sliding the one or more of the first and second coating liquids 116 and 124 along the slide surfaces 236 and 244 after the coating liquid flows out of the slots 122 and 180. How to. Passing the coating liquid 116 through a passageway defined by a manifold bar 228 with sharp edges and a downstream bar 232 with downstream lips; And sliding the coating liquid 116 flowing out of the passage along the slide surface 236 to form a continuous coating bead between the sharp edge of the manifold bar, the upstream die lip formed as a land, and the coated surface. Die coating method. The method of claim 9, Selecting the length L of the land, the corner angle A ₁ of the manifold bar, and the covering gap distance G between the sharp edge and the surface to be covered, in combination with each other; And selecting the overbyte O and the convergence angle C in combination with each other. The method of claim 6 or 10, Selecting the shape of the land to match the shape of the surface being covered.