Coating device

Abstract

To solve a problem that it is difficult to perform coating by a light-weight coating device which can be mounted on a holding member in a case that a coating liquid is applied to a sheet-like base material when the base material is horizontally transported.SOLUTION: A specific gravity of a base 10 provided with a die slot which measures a coating liquid and a manifold 11 which stores the coating liquid and supplies the coating liquid to a slot 18 at the downstream side is set to 3 or a lower value to enable coating by a light-weight coating device which can be mounted on a holding member of the base material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coating device, and more particularly to a coating device suitable for ejecting a coating liquid from a slit-shaped slot and forming a uniform thin coating film on a thin, long or sheet-like substrate. [Background technology]

[0002] When coating a sheet of substrate in the coating device described above, the coating head is mounted on a stage that holds the substrate, and a narrow gap of approximately 100 μm is maintained between the gap at the end of the slot and the substrate. The precision of this gap affects the coating thickness on the substrate, so it must be installed with a gap precision of 10 μm or less. In addition, if the gap at the end of the slot is uneven, there is a concern that the thickness of the coating fluid ejected from the manifold through the slot will be uneven across the width.

[0003] Therefore, it is necessary to grind the gap at the end of the slot with high precision, and then set the gap between the end of the slot and the substrate with high precision. To achieve this high-precision gap setting, Patent Documents 1 and 2 disclose configurations that use metal materials, such as stainless steel. However, metals that can be ground with high processing precision, such as stainless steel, have a specific gravity of about 7 to 8, making them heavy.

[0004] When coating a sheet of substrate by forming a uniform horizontal surface of coating fluid, the holding member (stage) that holds the substrate has a suction device that utilizes air bearings, which makes it impossible to place objects weighing more than 3 kg on the stage. While this important issue can be resolved by manufacturing the holding member from a lightweight metal with a specific gravity of 3 or less, such as aluminum, the grinding precision of lightweight metals is inferior to that of stainless steel, resulting in a large gap distribution at the end of the slot and a wide variation in the amount of coating fluid dispensed onto the substrate. In the case of table coating, a coating weight distribution of at least 10% delta, and preferably 3% delta or less, is required to achieve uniform coating.

[0005] Furthermore, Patent Document 3 discloses a slit die coater head for sheet-fed coating. Although the one in Patent Document 3 has a compact structure, it has a problem in that the gap is 20 μm, and it requires the skill to grind the gap with high precision and to assemble the whole unit with high precision. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7339445 [Patent Document 2] Patent No. 5545329 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-230361 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, when coating a coating liquid onto a sheet-like substrate that is not long, such as an A4 size substrate, while it is being transported horizontally, there is a problem in that it is difficult to coat the substrate using a lightweight coating device that can be mounted on a holding member.

[0008] The present invention aims to overcome the problems of the conventional coating devices, and to provide a coating device that can coat a sheet-like substrate using a lightweight coating device that can be mounted on a holding member that holds the substrate, and that can coat even long substrates using a lightweight coating device that can be mounted on a holding member that holds the substrate. [Means for solving the problem]

[0009] In order to overcome the above-mentioned problems, the coating device according to the present invention is a coating device that applies a coating liquid to a thin-film, long or sheet-like substrate being transported in the longitudinal direction, and is characterized in that the specific gravity of a base provided with a die slot that pre-meters the coating liquid and a manifold that stores the coating liquid and supplies it to the downstream slot is set to 3 or less. With this configuration, the specific gravity of the base is light, at 3 or less, making it possible to perform coating using a lightweight coating device that can be mounted on a holding member. The material of the base is not limited to metal.

[0010] Another coating device according to the present invention is characterized in that the equivalent diameter of the manifold is 7 mm or more. With this configuration, an equivalent diameter of 7 mm or more can be ensured when the manifold is a perfect circle, and an equivalent diameter of 11.5 mm or more can be ensured when the manifold is a semicircle.

[0011] In still another coating device according to the present invention, the base is formed of a metal mainly made of aluminum, and with this configuration, the metal mainly made of aluminum provides a certain degree of rigidity, allowing for stable dispensing of the coating solution.

[0012] A further coating device according to the present invention is characterized in that it is provided with an expansion prevention member that prevents the gap at the slot outlet downstream of the manifold from expanding. With this configuration, the gap at the slot outlet can be kept constant, allowing for stable discharge of the coating solution.

[0013] Another coating device according to the present invention is characterized in that the die of the die slot that pre-meters the coating liquid is held by a support member that supports the substrate to be transported. By adopting such a configuration, the device can be made compact. [Effects of the Invention]

[0014] According to the coating device of the present invention, the specific gravity of the base having the die slot and manifold is set to 3 or less, so that the base can be supported on a holding member that holds the substrate, making the entire device compact and allowing the coating liquid to be stably applied to the substrate. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a detailed longitudinal sectional view showing an embodiment of a coating device according to the present invention. [Figure 2] 2 is a schematic longitudinal cross-sectional view of the slot shown in FIG. 1, in which an adjustment bolt is provided to keep the gap between the slots in the width direction of the substrate constant. [Figure 3] FIG. 2 is a schematic vertical cross-sectional view of an embodiment in which the manifold in FIG. 1 is made into a perfect circle. [Figure 4] FIG. 2 is a schematic vertical cross-sectional view of an embodiment in which the manifold in FIG. 1 is semicircular. [Figure 5] 2 is a schematic longitudinal cross-sectional view of an embodiment in which the manifold in FIG. 1 is rectangular. [Figure 6] FIG. 2 is a schematic vertical cross-sectional view of an embodiment in which the manifold in FIG. 1 is trapezoidal. [Figure 7] A perspective view showing the opening of the slot DETAILED DESCRIPTION OF THE INVENTION

[0016] FIG. 1 is a detailed longitudinal cross-sectional view of an embodiment of a coating device according to the present invention. The base 10 is equipped with a circular manifold 11 that communicates with a die slot (not shown) for pre-metering the coating fluid. The base 10 is made of a metal such as aluminum or duralumin, an aluminum alloy, with a specific gravity of 3 or less. The base 10 comprises two halves 12A and 12B, each of which has an identical trapezoidal cross section, secured together so that their lower bases 13A and 13B are in contact with each other. The upper surfaces 14A and 14B of the halves 12A and 12B are flush with each other, and the lower bases 13A and 13B extend from the upper surfaces 14A and 14B, each of which is in contact with the other, and have a total length of 60 mm. The width of each upper surface 14A and 14B is 20 mm, for a total of approximately 40 mm.

[0017] Semicircular recesses 15A and 15B, which form half of the circular manifold 11, are formed in the upper bottom surfaces 13A and 13B, respectively, at positions 30 mm from the top surfaces 14A and 14B of the halves 12A and 12B. Each recess 15A and 15B has a diameter of 10 mm. A 30 mm long gap 16 between the lower bottom surfaces 13A and 13B above the recesses 15A and 15B that form the manifold 11 is filled with a shim 17 to fill the gap 16. Meanwhile, a 20 mm long slot-shaped gap 18 between the lower bottom surfaces 13A and 13B below the recesses 15A and 15B serves as a coating liquid passage.

[0018] Inclined surfaces 19A, 19B are connected at an angle of 50° to the lower ends of lower base surfaces 13A, 13B of each half body 12A, 12B, respectively, and each inclined surface 19A, 19B is connected to trapezoidal upper base surfaces 20A, 20B of each half body 12A, 12B. A pointed edge 21 is formed between the lower end of each lower base surface 13A, 13B and the lower end of each inclined surface 19A, 19B. A shim 22, a gap adjustment member that adjusts the width of gap 18 to the set coating thickness of the coating fluid, is removably disposed on pointed edge 21 at the tip of gap 18. The width of gap 18 formed by shim 22 can be set by the outer diameter of shim 22.

[0019] When the base 10 shown in FIG. 1 is turned sideways, the base 10 has a circular manifold 11 to which a coating liquid passage from a slot (not shown) in a die slot for pre-metering is connected from diagonally below, and a gap 18 for discharging the coating liquid from the manifold 11 to a substrate is positioned horizontally.

[0020] The equivalent diameter (Deq) of the manifold 11, which is the diameter of a cylinder having the same surface area, is generally expressed as Deq = 4 × A / L, where A is the cross-sectional area of the manifold and L is the wetted side length (inner circumferential length of the manifold).

[0021] In the above-described embodiment, the equivalent diameter is set to 10 mm, which is equal to the inner circumferential length of the manifold 11, since the manifold 11 is a perfect circle.

[0022] The base 10 is made of a material with a specific gravity of 3 or less, which means that compared to commonly used materials such as stainless steel, this material has a low elastic modulus and insufficient rigidity. Therefore, a gap-retaining member (not shown) is provided to prevent the base 10 from deflecting and maintain a constant gap between the two halves 12A and 12B in the longitudinal direction. A shim 22 is provided at an outlet 23 of the slot 18, downstream of the manifold 11 in the direction of flow of the coating liquid, as a discharge width regulating member for regulating the discharge width of the coating liquid at the slot 18. Adjusting the amount of threading of an adjustment bolt 24, which holds a base 25 of the base 10 to the base 10 shown in FIG. 2, changes the degree of deflection of the base 10 near the outlet 23 of the slot 18, thereby maintaining a constant gap at the slot outlet 23.

[0023] The coating fluid had a low shear viscosity of 10 Pas, a non-Newtonian coefficient of 0.7, and a zero shear viscosity of 30 Pas at a shear rate of 1 (1 / s), following the exponential law. The coating fluid was applied to the substrate in an amount of 200 μm, and the coating speed was 1 m / min. The coating fluid distribution was calculated using AndGraph (7) Manifold Effect (Non-Newtonian) Ver. 2, a calculation tool from AndTech.

[0024] 3 to 6 show manifolds of different shapes from the embodiment shown in Fig. 1, and each figure is provided with an annular supply pipe 26 for supplying the coating liquid pre-metered in the die slot to the manifold 11. Of these, Fig. 3 shows a manifold 11 with a circular cross section, Fig. 4 shows a semicircular cross section, Fig. 5 shows a rectangular cross section, and Fig. 6 shows a trapezoidal cross section, and thus manifolds 11 of different shapes can be formed.

[0025] FIG. 7 is a diagram showing the widthwise opening of slot 18 depending on the viscosity of the coating liquid. In the case of a low-viscosity coating liquid shown in FIG. 7A, the widthwise opening of slot 18 is constant, but in the case of a high-viscosity coating liquid shown in FIG. 7B, the widthwise opening of slot 18 becomes wider in the central portion. [Table 1]

[0026] Table 1 shows the coating evaluation of the coating liquid in Example 1-3 of the coating device of this embodiment in comparison with Comparative Example 1-4.

[0027] The manifold 11 has the same shape in Examples 1-3 and Comparative Examples 1-4, except for Comparative Example 4, which differs in the width of the base 10. The manifold 11 formed on the base 10 is circular in Example 1 and Comparative Examples 1 and 2, and semicircular in the remaining examples. The diameters and equivalent diameters of the manifold 11 are 10 mm for both Examples 1 and 2, 15 mm and 9.2 mm for Example 2, 11.5 mm and 7 mm for Example 3, 10 mm and 6.1 mm for Comparative Example 1, 5 mm for both Examples 2 and 3, 10 mm for both Examples 3 and 4, and 20 mm and 12.2 mm for Comparative Example 4. The base 10 is made of stainless steel with a specific gravity of 7.4 in Comparative Examples 3 and 4, and aluminum with a specific gravity of 2.7 in the other examples. The total weights (kg) of the bases 10 are 1.57, 1.59, 1.59, 1.56, 1.61, 4.29, and 4.56, respectively.

[0028] The coating weight distribution in the evaluation results shown in Table 1 is as follows: Example 1 (Δ1.7%), Example 2 (Δ2.4%), Example 3 (Δ7.0%), Comparative Example 1 (Δ12.3%), Comparative Example 2 (Δ27.4%), Comparative Example 3 (Δ1.7%), and Comparative Example 4 (Δ0.8%). Furthermore, the uniformity of the coating liquid was good for Example 1, Example 2, Comparative Example 3, and Comparative Example 4, with Example 3 being acceptable and Comparative Example 1-2 being poor. The overall evaluation was good for Examples 1-3, as they were able to achieve both coating weight and coating weight, and bad for Comparative Example 1-4, as they were unable to achieve both coating weight and coating weight.

[0029] As described above, according to this embodiment, the base is supported on a holding member that holds not only long but also sheet-like substrates, making it possible to miniaturize the entire apparatus and stably apply the coating liquid onto the substrate.

[0030] In this embodiment, the base 10 is described as being made of a light metal such as aluminum having a specific gravity of 3 or less, or duralumin, which is a type of aluminum alloy. However, the material of the base 10 of the present invention is not limited to the above-mentioned materials, and resin materials such as glass, polyimide, polycarbonate, polyarylate represented by U polymer, POM, PES, acrylic, and PVC can also be used. [Explanation of symbols]

[0031] 10 Foundations 11 Manifold 12A,12B half body 13A.13B Bottom surface 14A,14B Top surface 15A, 15B recess 16 Gap 17 Sim 18 slots 19A,19B Slope 20A,20B Top bottom surface 21 Apical edge 22 Sim 23 Slot Exit 24 Adjustment bolt 25 Base of adjustment bolt 26 Supply pipe

Claims

1. A coating device that applies a coating liquid to a thin-film, long or sheet-like substrate that is being transported in a longitudinal direction, A coating device characterized in that the specific gravity of a base provided with a die slot for pre-metering a coating liquid and a manifold for storing the coating liquid and supplying it to the downstream slot is set to 3 or less.

2. 2. The coating device according to claim 1, wherein the equivalent diameter of the manifold is 7 mm or more.

3. 2. The coating device according to claim 1, wherein the base is made of a metal mainly composed of aluminum.

4. 2. The coating device according to claim 1, further comprising an expansion prevention member for preventing the gap from expanding at the outlet of the slot downstream of the manifold.

5. 2. The coating device according to claim 1, wherein a die of a die slot for pre-metering the coating liquid is held by a support member for supporting the substrate to be transported.

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