A slot die for slot coating with improved coating efficiency and reduced bubble entrainment

Abstract

The application discloses a slot coating groove die head capable of improving coating efficiency and reducing bubble involvement, comprising a first coating module, a second coating module, a downstream gasket, an upstream gasket, a central gasket, an upstream guide vane and a downstream guide vane; the first coating module, the upstream gasket, the central gasket, the downstream gasket and the second coating module are sequentially fixed from left to right, the upper part of the upstream guide vane is fixedly connected with the lower part of the upstream gasket, and the upper part of the downstream guide vane is fixedly connected with the lower part of the downstream gasket. When coating, the upstream guide vane and the downstream guide vane can stabilize the upstream meniscus, destroy the vortex appearing on the contact surface between the upstream meniscus and the substrate, and reduce bubble involvement without damaging the overall flow, so that the surface quality of the film is ensured, and stable and efficient coating is realized. The array of micro grooves on the surface of the upstream guide vane and the downstream guide vane can ensure the stability of the flow, and further improve the preparation efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coating machines, in particular to a slit coating slot die head and use method for improving coating efficiency and reducing bubble entrapment. BACKGROUND

[0002] Slit coating technology plays a crucial role in thin film manufacturing, especially in high-precision coating applications, and has broad application prospects. This technology precisely controls the speed and width of the coating liquid flowing through the slit, resulting in uniform and controllable coating thickness, thereby ensuring high-precision thin film thickness consistency during production. This technology is particularly suitable for fields with stringent coating requirements, such as electronics, optics, and energy industries, and can achieve uniform coating on various complex surfaces such as curved surfaces and flexible substrates. In addition, with the continuous development of advanced manufacturing technology, slit coating technology has important application value in the mass production of functional thin films, optical films, and electronic thin films. Its control of thin film structure, performance, and quality consistency provides technical support for the innovation and commercialization of high-performance materials. Therefore, the research and development of slit coating technology is one of the keys to achieving high-end manufacturing and high-performance products.

[0003] However, the existing slit coating technology faces the problem of bubble entrapment in actual application, which is an important factor restricting coating efficiency and product quality. During the slit coating process, liquid coating is in contact with the substrate through the slit, and due to factors such as the flowability and interfacial tension of the coating liquid, bubbles are easily formed. Once these bubbles are wrapped and entrapped in the coating layer, they will cause bubble defects on the surface of the coating layer. The presence of bubbles not only affects the uniformity and smoothness of the film, but also may affect the functionality of the final product, especially in the fields of electronics, optics, and other high-precision requirements, the presence of bubbles may cause performance degradation. At the same time, due to the problem of bubble entrapment, the production efficiency in the coating process is often limited. In order to avoid the generation or entrapment of bubbles, additional control and processing are required during production, such as reducing the coating speed, optimizing the flow characteristics of the coating liquid, and increasing the surface tension of the substrate. Although these methods are effective, they often result in longer production cycles and higher costs.

[0004] Therefore, how to design a slit coating slot die head that effectively solves the problem of bubble entrapment and improves the stability and efficiency of the coating process has become a key problem that needs to be solved in the thin film coating industry. This not only requires the coating device to ensure uniformity and interface stability in the design, but also requires precise control of various liquids to meet the urgent needs of the industry for high-performance thin film coating processes. SUMMARY

[0005] In order to solve the above problems existing in the prior art, the present application designs a slit coating slot die head which can effectively solve the problem of bubble entrainment and improve the stability and efficiency of the coating process.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows: a slit coating slot die head for improving coating efficiency and reducing bubble entrainment, comprising a first coating module, a second coating module, a downstream gasket, an upstream gasket, a central gasket, an upstream guide vane and a downstream guide vane; the first coating module, the upstream gasket, the central gasket, the downstream gasket and the second coating module are fixed together from left to right, the upper part of the upstream guide vane is fixedly connected with the lower part of the upstream gasket, and the upper part of the downstream guide vane is fixedly connected with the lower part of the downstream gasket;

[0007] An arc-shaped manifold is formed in the inner wall of the first coating module, and an inclined flow channel is connected below the manifold;

[0008] The upstream gasket is provided with an inverted U-shaped groove, the top end shape of the inverted U-shaped groove is consistent with the upper end shape of the manifold of the first coating module, and the width of the inverted U-shaped groove is consistent with the width of the inclined flow channel connected below the manifold of the first coating module;

[0009] An inlet is formed in the outer wall of the second coating module;

[0010] An arc-shaped manifold is formed in the inner wall of the second coating module, and an inclined flow channel is connected below the manifold; the manifold is in communication with the inlet;

[0011] The downstream gasket is provided with an inverted U-shaped groove, the top end shape of the inverted U-shaped groove is consistent with the upper end shape of the manifold of the second coating module, and the width of the inverted U-shaped groove is consistent with the width of the inclined flow channel connected below the manifold of the second coating module;

[0012] The central gasket is provided with an inverted U-shaped groove at the bottom end, the top end shape of the inverted U-shaped groove is consistent with the upper end of the manifold of the first coating module, and the width of the inverted U-shaped groove is consistent with the inclined flow channel connected below the manifold of the first coating module.

[0013] Further, rectangular grooves are formed in the bottom end of the upstream gasket on the front and rear sides; the upstream guide vane comprises a rectangular connecting plate, an arc plate and a horizontal plate, the rectangular connecting plate has two pieces and is fixedly connected with the front and rear sides of the upper edge of the arc plate, and the lower edge of the arc plate is fixedly connected with the horizontal plate; the width d2 of the rectangular connecting plate is consistent with the width d1 of the rectangular groove formed at the bottom end of the upstream gasket, and the length h2 is greater than the length h1 of the rectangular groove formed at the bottom end of the upstream gasket;

[0014] The lower gasket is provided with rectangular grooves on both sides of the bottom end; the downstream flow guide piece comprises a rectangular connecting plate, a circular arc plate and a horizontal plate, the rectangular connecting plate is fixedly connected with the front and rear sides of the upper edge of the circular arc plate, and the lower edge of the circular arc plate is fixedly connected with the horizontal plate; the width d4 of the rectangular connecting plate is consistent with the width d3 of the rectangular groove at the bottom end of the lower gasket, and the length h4 is greater than the length h3 of the rectangular groove at the bottom end of the lower gasket.

[0015] Further, the first coating module, the upstream gasket, the central gasket, the downstream gasket and the second coating module are sequentially fixedly connected through bolts.

[0016] Further, the thickness w2 of the upstream flow guide piece is greater than the thickness w1 of the upstream gasket, and the two are in interference fit, and the installation process is locked by friction force; the thickness w4 of the downstream flow guide piece is greater than the thickness w3 of the downstream gasket, and the two are in interference fit, and the installation process is locked by friction force.

[0017] Further, the size of the upstream flow guide piece is selected according to the properties of the coating liquid and the coated substrate; and the size of the downstream flow guide piece is selected according to the properties of the coating liquid and the coated substrate.

[0018] Further, the surface of the upstream flow guide piece is provided with millimeter-level micro grooves in an array with an aspect ratio of 1:2; and the surface of the downstream flow guide piece is provided with micro grooves in an array.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. When the product is coated, the upstream flow guide piece and the downstream flow guide piece can stabilize the upstream meniscus without damaging the overall flow, destroy the vortex on the upstream meniscus and the contact surface of the substrate, and reduce the entrainment of air bubbles, so as to ensure the surface quality of the film and realize stable and efficient coating.

[0021] 2. The micro grooves in an array on the surface of the upstream flow guide piece and the downstream flow guide piece can ensure the stability of the flow, and further improve the preparation efficiency.

[0022] 3. The flat plate at the bottom of the upstream flow guide piece and the downstream flow guide piece can equivalently regulate the height of the tool bit, divide the downstream coating process into multiple coating processes with low tool bit height, and help the flow stability. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a schematic diagram (exploded view) of the overall structure of the application;

[0024] Figure 2 It is a sectional view of Figure 1 ;

[0025] Figure 3Schematic diagram of the surface array micro-grooves of the upstream guide vane and the downstream guide vane.

[0026] In the figure: 1-first coating module; 2-second coating module; 3-downstream gasket; 4-upstream gasket; 5-central gasket; 6-upstream guide vane; 7-downstream guide vane. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] like Figures 1-3 As shown, a slit coating slot die head for improving coating efficiency and reducing bubble entrapment includes a first coating module 1, a second coating module 2, a downstream gasket 3, an upstream gasket 4, a central gasket 5, an upstream guide plate 6, and a downstream guide plate 7; the first coating module 1, the upstream gasket 4, the central gasket 5, the downstream gasket 3, and the second coating module 2 are fixed together from left to right, the upper part of the upstream guide plate 6 is fixedly connected to the lower part of the upstream gasket 4, and the upper part of the downstream guide plate 7 is fixedly connected to the lower part of the downstream gasket 3;

[0029] An arc-shaped manifold is provided on the inner wall of the first coating module 1, and an inclined flow channel is connected below the manifold;

[0030] The upstream gasket 4 is provided with an inverted U-shaped groove, the top shape of which is consistent with the upper end shape of the manifold of the first coating module 1, and the width of which is consistent with the width of the inclined flow channel connected to the lower part of the manifold of the first coating module 1;

[0031] A liquid inlet is provided on the outer wall of the second coating module 2;

[0032] The inner wall of the second coating module 2 is provided with an arc-shaped manifold, and the lower part of the manifold is connected to an inclined flow channel; the manifold is connected to the liquid inlet;

[0033] The downstream gasket 3 is provided with an inverted U-shaped groove, the top shape of which is consistent with the upper end shape of the manifold of the second coating module 2, and the width of which is consistent with the width of the inclined flow channel connected below the manifold of the second coating module 2;

[0034] The bottom end of the central gasket 5 is provided with an inverted U-shaped groove, the top shape of which is consistent with the upper end of the manifold of the first coating module 1, and the width of which is consistent with the inclined flow channel connected below the manifold of the first coating module 1.

[0035] Further, the upstream gasket 4 is provided with rectangular grooves on both sides of the bottom end; the upstream flow guide piece 6 comprises a rectangular connecting plate, a circular arc plate and a horizontal plate, the rectangular connecting plate is fixedly connected with the front and back sides of the upper edge of the circular arc plate, and the lower edge of the circular arc plate is fixedly connected with the horizontal plate; the width d2 of the rectangular connecting plate is consistent with the width d1 of the rectangular groove at the bottom end of the upstream gasket 4, and the length h2 is greater than the length h1 of the rectangular groove at the bottom end of the upstream gasket 4.

[0036] The downstream gasket 3 is provided with rectangular grooves on both sides of the bottom end; the downstream flow guide piece 7 comprises a rectangular connecting plate, a circular arc plate and a horizontal plate, the rectangular connecting plate is fixedly connected with the front and back sides of the upper edge of the circular arc plate, and the lower edge of the circular arc plate is fixedly connected with the horizontal plate; the width d4 of the rectangular connecting plate is consistent with the width d3 of the rectangular groove at the bottom end of the downstream gasket 3, and the length h4 is greater than the length h3 of the rectangular groove at the bottom end of the downstream gasket 3.

[0037] Further, the first coating module 1, the upstream gasket 4, the central gasket 5, the downstream gasket 3 and the second coating module 2 are sequentially fixedly connected by bolts.

[0038] Further, the thickness w2 of the upstream flow guide piece 6 is greater than the thickness w1 of the upstream gasket 4, and the upstream flow guide piece 6 is locked by friction force in the installation process; the thickness w4 of the downstream flow guide piece 7 is greater than the thickness w3 of the downstream gasket 3, and the downstream flow guide piece 7 is locked by friction force in the installation process.

[0039] Further, the size of the upstream flow guide piece 6 is selected according to the properties of the coating liquid and the coating substrate; and the size of the downstream flow guide piece 7 is selected according to the properties of the coating liquid and the coating substrate.

[0040] Further, the surface of the upstream flow guide piece 6 is provided with millimeter-level micro grooves with an array aspect ratio of 1:2; and the surface of the downstream flow guide piece 7 is provided with micro grooves with an array.

[0041] According to the coating material and process, the steps of adjusting the flow guide piece are as follows:

[0042] Firstly, according to the coating process, the substrate wettability and the used material, the appropriate upstream flow guide piece 6 and downstream flow guide piece 7 are selected, and the selected upstream flow guide piece 6 and downstream flow guide piece 7 are respectively inserted into the rectangular grooves respectively provided on the left and right sides of the bottom end of the upstream gasket 4 and the downstream gasket 3. Then, the first coating module 1, the upstream gasket 4, the central gasket 5, the downstream gasket 3 and the second coating module 2 are locked by bolts, and the upstream flow guide piece 6 and the downstream flow guide piece 7 are locked by interference fit.

[0043] The optical liquid to be coated flows into the circular arc-shaped manifold formed in the inner wall of the first coating module 1 and the circular arc-shaped manifold formed in the inner wall of the second coating module 2 from the inlet formed in the outer wall of the second coating module 2, and then flows into the flow channel below the manifold, and flows into the upstream flow guide 6 and the downstream flow guide 7 through the slit gap formed by the upstream gasket 4, the central gasket 5 and the downstream gasket 3. When the fluid flows through the upstream flow guide 6 and the downstream flow guide 7, the stability of the flow is ensured due to the array of micro grooves on the surface of the upstream flow guide 6 and the downstream flow guide 7. At the same time, through research, it is found that the bubble entrainment is mainly caused by the vortex generated at the contact surface between the upstream meniscus and the substrate, and the upstream flow guide 6 and the downstream flow guide 7 can destroy the vortex without changing the overall flow direction, reduce the bubble entrainment, improve the coating speed and ensure the surface quality of the film.

[0044] The above description is for the ordinary skilled in the art to make various corresponding changes and modifications according to the technical solutions and technical concepts of the present application, and all these changes and modifications shall belong to the protection scope of the claims of the present application.

Claims

1. A slot coating die head for improving coating efficiency and reducing bubble entrapment, characterized by: The invention comprises a first coating module (1), a second coating module (2), a downstream gasket (3), an upstream gasket (4), a central gasket (5), an upstream guide plate (6) and a downstream guide plate (7); the first coating module (1), the upstream gasket (4), the central gasket (5), the downstream gasket (3) and the second coating module (2) are fixed together in sequence from left to right, the upper part of the upstream guide plate (6) is fixedly connected to the lower part of the upstream gasket (4), and the upper part of the downstream guide plate (7) is fixedly connected to the lower part of the downstream gasket (3); The inner wall of the first coating module (1) is provided with an arc-shaped manifold, and an inclined flow channel is connected below the manifold; The upstream gasket (4) is provided with an inverted U-shaped groove, the top shape of the inverted U-shaped groove is consistent with the shape of the upper end of the manifold of the first coating module (1), and the width of the inverted U-shaped groove is consistent with the width of the inclined flow channel connected below the manifold of the first coating module (1); A liquid inlet is provided on the outer wall of the second coating module (2); The inner wall of the second coating module (2) is provided with an arc-shaped manifold, and an inclined flow channel is connected below the manifold; the manifold is connected to the liquid inlet; The downstream gasket (3) is provided with an inverted U-shaped groove, the top shape of the inverted U-shaped groove is consistent with the shape of the upper end of the manifold of the second coating module (2), and the width of the inverted U-shaped groove is consistent with the width of the inclined flow channel connected below the manifold of the second coating module (2); An inverted U-shaped groove is formed at the bottom end of the central gasket (5), the top end of the inverted U-shaped groove is consistent with the upper end of the manifold of the first coating module (1), and the width of the inverted U-shaped groove is consistent with the inclined flow channel connected below the manifold of the first coating module (1); The upstream gasket (4) is provided with rectangular grooves on both the front and rear sides of the bottom end; the upstream guide plate (6) comprises a rectangular connecting plate, an arc plate and a horizontal plate, the rectangular connecting plate has two pieces, which are fixedly connected to the front and rear sides of the upper edge of the arc plate, and the lower edge of the arc plate is fixedly connected to the horizontal plate; the width d2 of the rectangular connecting plate is consistent with the width d1 of the rectangular groove provided at the bottom end of the upstream gasket (4), and the length h2 is greater than the length h1 of the rectangular groove provided at the bottom end of the upstream gasket (4); The downstream gasket (3) is provided with rectangular grooves on the front and rear sides of the bottom end respectively; the downstream guide plate (7) comprises a rectangular connecting plate, an arc plate and a horizontal plate, the rectangular connecting plate has two pieces, which are fixedly connected to the front and rear sides of the upper edge of the arc plate respectively, and the lower edge of the arc plate is fixedly connected to the horizontal plate; the width d4 of the rectangular connecting plate is consistent with the width d3 of the rectangular groove provided at the bottom end of the downstream gasket (3), and the length h4 is greater than the length h3 of the rectangular groove provided at the bottom end of the downstream gasket (3).

2. A slot coating die head for improving coating efficiency and reducing bubble entrapment according to claim 1, characterized in that: The first coating module (1), the upstream gasket (4), the central gasket (5), the downstream gasket (3) and the second coating module (2) are fixedly connected in sequence by bolts.

3. A slot coating die head for improving coating efficiency and reducing bubble entrapment according to claim 1, characterized in that: The thickness w2 of the upstream guide plate (6) is greater than the thickness w1 of the upstream gasket (4), and is an interference fit, and is locked by friction during the installation process; the thickness w4 of the downstream guide plate (7) is greater than the thickness w3 of the downstream gasket (3), and is an interference fit, and is locked by friction during the installation process.

4. A slot coating die head for improving coating efficiency and reducing bubble entrapment according to claim 1, characterized in that: The size of the upstream guide plate (6) is selected according to the properties of the coating liquid and the coating substrate; the size of the downstream guide plate (7) is selected according to the properties of the coating liquid and the coating substrate.

5. The slit coating slot die head for improving coating efficiency and reducing bubble entrapment according to claim 1, characterized in that: The surface of the upstream guide plate (6) has an array of millimeter-scale micro grooves with an aspect ratio of 1:2; the surface of the downstream guide plate (7) has an array of micro grooves.

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