Die nozzle and coating device using same

Abstract

To provide a coating apparatus coating and drying functional coating material composed of functional powder, binder resin and a solvent on a substrate to form a functional thin film.SOLUTION: A coating apparatus includes: a liquid supply nozzle applying coating material on a substrate continuously travelling on a roll; and a liquid feeding means supplying the coating material to the liquid supply nozzle. When it is defined that a side where the substrate approaches to the nozzle is upstream and a side where the substrate comes apart from the nozzle is downstream, the liquid supply nozzle is composed of a first block forming a downstream-side nozzle and a second block forming an upstream-side nozzle along at least the travelling direction of the substrate. The tip end of the first block is provided with a wire bar having an uneven shape, and the wire bar comes in contact with the top face of the tip end of the second block.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a die nozzle for applying and drying a functional coating material comprising a functional powder, a binder resin, and a solvent onto a substrate to form a functional thin film, and to a coating device using the same. [Background technology]

[0002] Conventional die nozzles and coating devices using them include the die method, in which the coating solution is extruded from the die nozzle to form a coating film on the substrate, and the gravure method, in which the coating solution is transferred to the recesses of a gravure plate, and the coating solution on the surface is scraped off with a doctor blade and transferred to the substrate. These devices are used to directly coat the substrate to form a functional thin film.

[0003] In general, the gravure method is superior for forming thin functional thin films, but the die nozzle method is superior for forming functional thin films over a wide area. When using the die nozzle method for forming thin functional thin films, there is a device that supplies paint from both sides through slits formed on both sides of a bar coater placed at the tip of the nozzle, and discharges excess ink from one side (see, for example, Patent Document 1).

[0004] FIG. 8 shows a conventional coating device described in Patent Document 1 and a developed view. By supplying a predetermined amount of coating liquid 812 to a rotating bar 829 from the upstream and downstream sides of the conveying direction of the web 811 and by having a discharge mechanism, it is possible to form a thin functional thin film.

[0005] Furthermore, as a conventional die nozzle type coating device, there is a device in which a porous member is embedded in the nozzle so that when the tip of the nozzle, which is set facing downward, comes into contact with the object to be coated and coating is performed, the porous member comes into contact with the object to be coated (for example, see Patent Document 2).

[0006] FIG. 9 shows a conventional coating device described in Patent Document 2. This conventional coating device applies a coating liquid to a porous material by bringing the porous material and the substrate into contact with each other. This coating device includes a porous material to which the coating liquid is supplied from one end and which applies the coating liquid to the substrate from the other end, a conveyor that moves the substrate and the porous material relative to each other, and a liquid supply nozzle that supplies the coating liquid to one end of the porous material. This coating device allows the bubble diameter of the porous material in the other end region to be larger than the bubble diameter of the porous material in the one end region. Therefore, the bubble diameter in the region of the porous material where the coating liquid is supplied can be made smaller than the bubble diameter in the region that contacts the substrate, and the coating liquid can be supplied uniformly across the width of the porous material. This allows for easy and uniform coating of a film even on substrates that are warped or wavy. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5150907 [Patent Document 2] Patent No. 5442054 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the configuration of Patent Document 1 uses a bar coater to apply a coating solution to a web 811 in response to the rotational movement of a bar 829 that adjusts the coating amount. The coating device includes basic blocks 850 and 853, each of which has an upstream cavity block 823 and a downstream cavity block 824, and width-determining blocks 851, 852, 854, and 855 located at both ends of the basic blocks 850 and 853. This requires high dimensional accuracy for each basic block and the bar coater, as well as precise assembly accuracy for the basic blocks. Problems with component dimensional accuracy and assembly accuracy can result in uneven coating or coating streaks, making it difficult to form a stable coating film. Furthermore, because the bar coater rotates, component dimensions change over time due to wear of the sliding parts, necessitating frequent and complex maintenance. Furthermore, the requirement for extremely high dimensional accuracy results in extremely high component costs.

[0009] In the configuration of Patent Document 2, when a coating liquid containing fine particles is used, the fine particles clog the pores of the porous material, causing the pores to become increasingly clogged over time. This makes it difficult to stably supply the coating liquid. After a certain period of use, an additional cleaning process is required. If the clogged pores cannot be sufficiently eliminated even by cleaning, problems arise: coating film formation varies; and the porous material becomes a consumable item and requires replacement. Furthermore, because the nozzle contacts the object to be coated in a linear fashion, problems arise: damage to the substrate; and variations in film thickness due to wear of the nozzle over time.

[0010] The present invention aims to solve the problems of the prior art by providing a die nozzle and a coating device using the same that can apply and dry a functional coating material consisting of a functional powder, a binder resin, and a solvent to a substrate to form a functional thin film. [Means for solving the problem]

[0011] In order to achieve the above object, the die nozzle of the present invention comprises a liquid supply nozzle that applies paint onto a substrate that is continuously running on a roll, and a liquid delivery means that supplies paint to the liquid supply nozzle. If the side on which the substrate approaches the liquid supply nozzle is defined as the upstream side, and the side on which the substrate moves away from the liquid supply nozzle is defined as the downstream side, the liquid supply nozzle is composed of at least a first block that defines the downstream nozzle along the running direction of the substrate, and a second block that defines the upstream nozzle. A wire bar with an uneven shape is provided at the tip of the first block, and the wire bar is in contact with the upper surface of the tip of the second block. [Effects of the Invention]

[0012] As described above, the die nozzle and coating device using the same according to the present invention can apply a functional paint consisting of a functional powder, a binder resin, and a solvent with little variation and reduce wear and tear on parts of the die coating section due to abrasion, and can then dry on a substrate to form a thin functional thin film. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view showing the basic configuration of a die nozzle according to a first embodiment and a coating device using the same. [Figure 2] 4 is an enlarged view showing the shape of a wire bar provided at the tip of a first block in the coating device according to the first embodiment. FIG. [Figure 3-1] 3 is an enlarged view of a liquid supply nozzle in the coating apparatus according to the first embodiment. FIG. [Figure 3-2] FIG. 3-2 is a schematic partial enlarged view showing a lip surface at the tip of the upstream second block in FIG. 3-1. [Figure 3-3] FIG. 3-2 is an exploded perspective view showing the configuration of the liquid supply nozzle of FIG. 3-1. [Figure 4] 1 is a schematic diagram of a process for forming a functional thin film in the first embodiment. [Figure 5] FIG. 10 is a schematic cross-sectional view showing the cross-sectional configuration of a die nozzle and coating device having a buffer function for a wire bar according to a second embodiment. [Figure 6]10 is an enlarged view of a liquid supply nozzle having a load control unit for a wire bar in a coating device according to a second embodiment. FIG. [Figure 7] FIG. 10 is a schematic view of a roll having a shock-absorbing function in a coating device according to a second embodiment. [Figure 8] FIG. 1 is a development view of a conventional coating device described in Patent Document 1. [Figure 9] FIG. 1 is a diagram showing a conventional coating device described in Patent Document 2. DETAILED DESCRIPTION OF THE INVENTION

[0014] The die nozzle of the first aspect comprises a liquid supply nozzle that applies paint onto a substrate that runs continuously on a roll, and a liquid delivery means that supplies paint to the liquid supply nozzle. If the side where the substrate approaches the liquid supply nozzle is defined as the upstream side, and the side where the substrate moves away from the liquid supply nozzle is defined as the downstream side, the liquid supply nozzle is composed of a first block that defines the downstream nozzle and a second block that defines the upstream nozzle at least along the running direction of the substrate, and a wire bar with an uneven shape is provided at the tip of the first block, and the wire bar is in contact with the upper surface of the tip of the second block.

[0015] In this configuration, by placing a blade, which is the uneven portion of the wire bar 108 having an uneven R-curved surface, at the tip of the downstream first block 106, it becomes possible to apply the ink by bringing the wire bar 108 into contact with the substrate. The uneven R-curved surface of the wire bar 108 narrows the ink flow path, increasing the flow rate and enabling the stable formation of a coating film on the substrate. Furthermore, by bringing the blade into contact with the tip of the upstream second block 107, the opening area is narrowed, making it possible to supply ink to the nozzle tip even with a small amount of ink being delivered, enabling the formation of a thin film.

[0016] A die nozzle according to a second aspect may be the die nozzle according to the first aspect, wherein the first block is a member having an uneven shape in which the difference between the bottom and the apex of the unevenness at the tip of the downstream nozzle is 50 to 300 μm.

[0017] A die nozzle according to a third aspect may be the die nozzle according to the first or second aspect, wherein the slit gap of the liquid supply nozzle is 0.1 mm or more and 2 mm or less.

[0018] A die nozzle according to a fourth aspect is the die nozzle of any one of the first to third aspects, wherein a lip surface at a tip of the upstream second block provided in the liquid supply nozzle may be flat.

[0019] A coating device according to a fifth aspect includes the die nozzle according to any one of the first to fourth aspects and a roll that is disposed opposite the liquid supply nozzle of the die nozzle and that continuously transports the substrate, and the roll has a member made of resin disposed in the area facing the liquid supply nozzle.

[0020] A sixth aspect of the coating device is the fifth aspect, wherein the roll has a diameter of 50 mm or more.

[0021] A seventh aspect of the manufacturing method of a battery electrode is a method of manufacturing a battery electrode using the coating device according to the fifth or sixth aspect, and includes a coating step of coating an active material paste supplied to a liquid supply nozzle by a liquid delivery means onto a continuously running substrate, that is, a current collector, and the active material paste is discharged from between the uneven shape of a wire bar provided at the tip of a first block and the flat surface at the tip of a second block, and coated onto the current collector.

[0022] Hereinafter, a die nozzle and a coating device according to an embodiment will be described with reference to the accompanying drawings. Note that substantially the same components in the drawings are given the same reference numerals.

[0023] (Embodiment 1) 1 is a schematic cross-sectional view showing the basic configuration of a die nozzle 100 according to embodiment 1 and a coating device 200 using the same. For convenience, in the drawing, the coating direction of the paint is shown as the X direction, the vertically upward direction as the Z direction, and the depth direction of the paper as the Y direction (width direction). This die nozzle 100 includes a liquid supply nozzle 105 and a liquid delivery means for supplying paint to the liquid supply nozzle 105, which applies paint to a substrate 109 on a continuously running roll 110. Here, the side where the substrate 109 approaches the liquid supply nozzle 105 is defined as the upstream side, and the side where the substrate 109 moves away from the liquid supply nozzle 105 is defined as the downstream side. The liquid supply nozzle 105 is composed of a first block 106 that defines the downstream nozzle and a second block 107 that defines the upstream nozzle. A wire bar 108 having an uneven shape is provided at the tip of the first block 106. The wire bar 108 is in contact with the upper surface of the tip of the second block 107. The wire bar 108 also extends in the Y direction.

[0024] This die nozzle 100 allows a functional paint consisting of functional powder, binder resin, and solvent to be applied to a substrate with little variation and reduces wear and tear on the die coating parts, and can be dried to form a thin functional thin film.

[0025] Furthermore, the die nozzle 100 and a roll 110 that is provided at a position opposite the liquid supply nozzle 105 of the die nozzle 100 and that allows the substrate 109 to travel continuously constitute a coating device 200.

[0026] Each of the components constituting the coating device 200 will be described below.

[0027] <Paint> The coating liquid 101 is a functional coating material made of, for example, functional powder, binder resin, and solvent.

[0028] <Liquid delivery means> The liquid delivery means includes, for example, a tank portion 102 for holding the coating liquid 101, a liquid delivery mechanism 103 for delivering the coating liquid 101 in a precise, fixed amount, and a liquid spreading mechanism 104 for spreading the coating liquid in the horizontal direction (within the XY plane).

[0029] <Liquid supply nozzle> The liquid supply nozzle 105 is composed of a first block 106 that defines the upstream nozzle and a second block 107 that defines the downstream nozzle. A wire bar 108 having an uneven shape is provided at the tip of the first block 106. The wire bar 108 is in contact with the upper surface of the tip of the second block 107. The wire bar 108 extends in the Y direction as shown in FIG. 2.

[0030] <role> The roll 110 is capable of continuously running with the substrate 109 on which the thin film is to be formed wound around it. The roll 110 is disposed opposite the liquid supply nozzle 105 in the X direction. The roll 110 is capable of rotating clockwise.

[0031] 2 is an enlarged view showing the shape of the wire bar 108 provided at the tip of the first block in the coating apparatus according to embodiment 1. The wire bar 108 has an R-shaped curved surface 201, and dimension A is defined as the uneven pitch, and dimension B is defined as the uneven height.

[0032] Fig. 3-1 is an enlarged view of the liquid supply nozzle 105 in the coating apparatus according to embodiment 1. Fig. 3-2 is a schematic enlarged partial view showing the lip surface 202 at the tip of the second block 107 on the upstream side in Fig. 3-1. Fig. 3-3 is an exploded perspective view showing the configuration of the liquid supply nozzle 105 in Fig. 3-1. Details will be described using Figures 3-1 to 3-3. The liquid supply nozzle 105 of the coating device according to the first embodiment includes a wire bar 108, which is embedded in the tip of a first block 106 made of two pieces of stainless steel, aluminum, or the like and has a width equal to or greater than the coating width. The wire bar 108 is in contact with the upper surface of a second block 107. For example, when the average particle size of the functional powder is 2 μm, the uneven pitch A of the curved surface of the wire bar 108 may be, for example, 100 μm, and the uneven height B may be, for example, 50 to 300 μm. The uneven pitch A and curved surface 201 of the wire bar 108 may be obtained by wrapping a metal wire of the appropriate dimensions around a metal round bar, or by machining the metal round bar to have an uneven shape.

[0033] The coating film formation process will be explained using FIG. (1) A coating liquid 101 is supplied to a liquid supply nozzle 105 via a liquid supply mechanism 103 at a predetermined speed, passes through the uneven portion of a wire bar 108, and forms a coating film 111 on a substrate 109. (2) The width of the coating film is controlled to a predetermined width by a liquid spreading mechanism 104 that spreads the coating liquid horizontally. (3) When the coating liquid is applied to the substrate 109, the wire bar 108 attached to the tip of the first block 106 has an uneven, rounded surface, which narrows the ink flow path, increasing the flow rate of the coating liquid and enabling the formation of a highly accurate thin film on the substrate 109. In addition, by contacting the tip of the second block 107 with the blade, which is the uneven part of the wire bar, the opening area can be stably controlled even if it is extremely small, making it possible to supply ink to the nozzle tip without variation even when the amount of liquid sent is minute. (4) The coating liquid coming out from the uneven portion of the wire bar 108 forms a puddle at the tip of the second block 107, making it possible to form a thin film on the surface of the substrate 109. As shown in FIG. 3-2, the tip of the second block 107 is called a lip surface 202, and its shape may be either a sharp edge or a flat shape, and can be selected depending on the fluidity of the coating liquid and the thickness of the thin film. Note that the lip surface 202 may be a small flat surface, for example, about 0.1 mm.

[0034] The slit gap 301 of the liquid supply nozzle is important for the thickness of the coating film. When forming a thin film with a thickness of 15 μm to 1 mm in an undried state immediately after coating, the slit gap 301 is set to 0.1 mm or more and 2 mm or less. It is desirable to determine the slit gap based on the viscosity and thixotropy of the coating liquid.

[0035] The coating liquid thus stably supplied is applied to a substrate 109 wound around a roll 110, and a thin functional thin film 111 is formed.

[0036] 4(a) to 4(c) are schematic cross-sectional views showing the change over time in the surface shape of the coating surface in the functional thin film formation process. Immediately after application, the curved surface shape of the wire bar 108 attached to the tip of the nozzle is transferred to form a curved surface shape 401 (Fig. 4(a)), but over time the coating liquid sags horizontally, forming a smooth coating film 402 (Fig. 4(b)). After drying, it becomes a functional thin film 111 (Fig. 4(c)). Since it is necessary to form a smooth coating film before drying, the coating liquid is adjusted using the concentration of a volatile solvent that adjusts the viscosity of the coating liquid.

[0037] (Embodiment 2) 5 is a schematic cross-sectional view showing the cross-sectional configuration of a die nozzle 100a and a coating device 200a having a buffer mechanism 501 for a wire bar 108 according to embodiment 2. FIG. 5 shows an overall view of a coating device having a buffer mechanism 501 that allows the wire bar 108 to move in the direction opposite the roll 110.

[0038] Another problem is that the thickness of the substrate 109 on which the functional thin film 111 is formed may not have a constant dimensional accuracy. In such cases, the downstream nozzle is provided with a wire bar 108 having an uneven tip, and the coating liquid is applied to the substrate 109 fed by the roll 110 with the wire bar 108 in contact with the substrate 109. Therefore, variations in the thickness of the substrate 109 may prevent the wire bar 108 from contacting the substrate 109 in parallel, causing the substrate 109 to be scraped locally, or the wire bar 108 may not contact the substrate 109 at all, resulting in the formation of a thick coating film. In such cases, uneven coating or coating streaks may occur, and the substrate 109 may be damaged.

[0039] Furthermore, in order to form a particularly thin functional thin film, the parallelism between the nozzle and the roll 110 is important for stable application of the coating liquid. If the mounting accuracy of the components or the dimensional accuracy of the parts is insufficient, as in the case described above, the wire bar 108 will not be able to contact the substrate 109 parallel to the substrate 109, which may result in localized scraping of the substrate 109, or the wire bar 108 not contacting the substrate 109 at all, resulting in the formation of a thick coating film. In such cases, there is a possibility of uneven coating or coating streaks occurring, and damage to the substrate 109 may occur.

[0040] Therefore, in the die nozzle 100a and coating device 200a according to the second embodiment, a buffer mechanism 501 is provided at the portion where the wire bar 108 is attached. This makes it possible to compensate for variations in the dimensional accuracy of the substrate 109 and to ensure the parallelism between the nozzle and the roll 110, thereby enabling the stable application of the coating liquid to form a thin functional thin film.

[0041] FIG. 6 is an enlarged view of a liquid supply nozzle having a load control unit for a wire bar in a coating apparatus according to the second embodiment. The upstream nozzle has a wire bar 108 having an uneven shape at the tip of the nozzle, a buffer mechanism 501 that enables the wire bar 108 to move in the direction facing the roll 110, and a weight control unit.

[0042] The buffer mechanism 501 can be made of, for example, a resin material or an elastomer material having viscoelastic properties.

[0043] The load control section is provided with a spring 601 for attachment, so that the wire bar 108 and the roll 110 can be brought into contact with each other with a constant load.

[0044] FIG. 7 is a schematic diagram of a roll 110 having a buffer function 701 in a coating apparatus 200a according to the second embodiment. As described above, variations in the thickness of the substrate 109 or a decrease in the accuracy of the attachment of components can cause the substrate 109 to be scraped, or the wire bar 108 can not contact the substrate 109, resulting in the formation of a thick coating film. As shown in Figure 7, by providing a buffer function 701 to the roll 110, the variations in the thickness of the substrate 109 and a decrease in the accuracy of the attachment of components can be absorbed, thereby suppressing the occurrence of uneven coating, coating streaks, and damage to the substrate 109.

[0045] As the cushioning function 701 of the roll 110, for example, a sheet of a resin material or an elastomer material having viscoelastic properties can be used as the surface layer of the roll 110.

[0046] Here, the material of the wire bar 108 may be a highly durable material such as a metal iron-based material (such as SUS), titanium, or Ni alloy, as a wear prevention measure, for example, by applying a coating liquid which is a functional paint consisting of functional powder, binder resin, and solvent.

[0047] Furthermore, when using a coating liquid that does not require consideration of wear of the wire bar 108, a resin material such as engineering plastic may be used.

[0048] Furthermore, even if damage to the substrate 109 by the wire bar 108 is expected, by using a soft plastic material with hardness adjusted according to the substrate 109, it is possible to form a thin functional thin film without damaging the substrate 109.

[0049] The coating device according to the present disclosure may also be used to manufacture battery electrodes for lithium secondary batteries. For example, the active material paste supplied to the liquid supply nozzle by the liquid delivery means may be coated onto a continuously running current collector, which is a substrate. In this case, in the coating step, the active material paste is discharged from between the uneven surface of the wire bar provided at the tip of the first block and the flat surface at the tip of the second block, and coated onto the current collector.

[0050] In addition, an antistatic functional film can be formed by using a coating solution containing conductive particles on the plastic film substrate 109. Also, a thin functional thin film such as an anti-reflection film can be formed by using a coating solution containing titanium oxide particles or barium titanate particles.

[0051] In addition, the present disclosure includes appropriate combinations of any of the various embodiments and / or examples described above, and can achieve the effects of each embodiment and / or example. [Industrial Applicability]

[0052] The die nozzle of the present invention and the coating device using the same make it possible to form thin functional thin films, such as battery electrodes formed on a metal substrate 109 used in a lithium secondary battery using a coating liquid containing an active material, antistatic functional films formed on a plastic film substrate 109 using a coating liquid containing conductive particles, and anti-reflection films formed using a coating liquid containing titanium oxide particles or barium titanate particles. [Explanation of symbols]

[0053] 100 Die Nozzle 101 Coating liquid 102 Tank section 103 Liquid delivery mechanism 104 Liquid spread mechanism 105 Liquid supply nozzle 106 Block 1 107 Block 2 108 Wire Bar 109 Base material 110 rolls 111 Functional Thin Films 200 Coating equipment 201 R curved surface 202 Lip surface 301 Slit Gap 401 R curved shape 402 Smooth coating film 501 Buffer mechanism 601 Spring 701 Buffer function

Claims

1. a liquid supply nozzle for applying a coating material onto a substrate that is continuously running on a roll; a liquid supply means for supplying paint to the liquid supply nozzle; Equipped with When the side where the substrate approaches the liquid supply nozzle is defined as the upstream side, and the side where the substrate moves away from the liquid supply nozzle is defined as the downstream side, the liquid supply nozzle is composed of at least a first block that defines a downstream nozzle and a second block that defines an upstream nozzle along the running direction of the substrate, a wire bar having an uneven shape is provided at a tip of the first block, and the wire bar is in contact with a surface of the tip of the second block on the slit gap side.

2. The die nozzle according to claim 1, wherein the wire bar is a member having an uneven shape in which the difference between the bottom and top of the unevenness is 50 to 300 μm.

3. 3. The die nozzle according to claim 1, wherein the slit gap of the liquid supply nozzle is 0.1 mm or more and 2 mm or less.

4. The die nozzle according to claim 1 , wherein a lip surface at a tip end of the second block on the upstream side of the liquid supply nozzle is flat.

5. The die nozzle according to any one of claims 1 to 4; a roll that is provided at a position facing the liquid supply nozzle of the die nozzle and that allows the substrate to continuously travel; Equipped with The roll is a coating device in which a member made of resin is disposed in a range facing the liquid supply nozzle of the die nozzle.

6. The coating device according to claim 5 , wherein the roll has a diameter of 50 mm or more.

7. 7. A method for manufacturing a battery electrode using the coating apparatus according to claim 5 or 6, comprising a coating step of coating the active material paste supplied to the liquid supply nozzle by the liquid delivery means onto a continuously traveling current collector as the substrate, the active material paste is discharged from between the uneven shape of the wire bar provided at the tip of the first block and the flat surface at the tip of the second block, and coated onto the current collector.

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