Slit coating groove die head capable of improving coating efficiency and reducing bubble entrainment

Abstract

The invention discloses a slit coating groove die head capable of improving coating efficiency and reducing bubble entrainment. The slit coating groove die head comprises a first coating module, a second coating module, a downstream gasket, an upstream gasket, a central gasket, an upstream flow deflector and a downstream flow deflector, the first coating module, the upstream gasket, the central gasket, the downstream gasket and the second coating module are sequentially fixed together from left to right, the upper part of the upstream flow deflector is fixedly connected with the lower part of the upstream gasket, and the upper part of the downstream flow deflector is fixedly connected with the lower part of the downstream gasket. During coating, the upstream flow deflector and the downstream flow deflector can stabilize the upstream meniscus, destroy vortexes appearing on the contact surface of the upstream meniscus and the substrate and reduce bubble entrainment under the condition of not destroying overall flow. Therefore, film surface quality is guaranteed, and stable and efficient coating is achieved. The surfaces of the upstream flow deflector and the downstream flow deflector are provided with arrayed micro grooves, so that the flowing stability can be ensured, and the preparation efficiency is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of coating machines, and in particular to a slit coating slot die head and a use method thereof for improving coating efficiency and reducing bubble entrainment. Background Art

[0002] Slit coating technology plays a vital 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, making the coating uniform and the thickness controllable, thereby ensuring high-precision film thickness consistency during the production process. This technology is particularly suitable for fields with strict requirements on coatings, such as electronics, optics, and the energy industry, and can achieve uniform coating on a variety of 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 large-scale production of new materials such as functional films, optical films, and electronic films. Its consistent control of film structure, performance, and quality 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 practical applications, which has become an important factor restricting coating efficiency and product quality. During the slit coating process, when the liquid coating contacts the substrate through the slit mouth, bubbles are easily formed due to factors such as the fluidity and interfacial tension of the coating liquid. Once these bubbles are wrapped by the coating liquid and drawn into the coating, bubble defects will appear on the coating surface. The presence of bubbles not only affects the uniformity and smoothness of the film, but may also affect the functionality of the final product. Especially in the fields of electronics and optics with high precision requirements, the appearance of bubbles may lead to performance degradation. At the same time, due to the problem of bubble entrapment, the production efficiency of the coating process is often limited. In order to avoid the generation or entrapment of bubbles, additional control and processing are required during the production process, such as reducing the coating speed, optimizing the flow characteristics of the coating liquid, and increasing the surface tension of the substrate. Although these measures are effective, they often lead to extended production cycles and increased costs.

[0004] In view of this, how to design a slot coating die that effectively solves the problem of bubble entrainment and improves the stability and efficiency of the coating process has become a key issue that the film coating industry needs to solve urgently. This not only requires the coating device to ensure coating uniformity and interface stability in structural design, but also requires precise control of multiple liquids to meet the industry's urgent demand for high-performance film coating processes. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention aims to design a slit coating slot die head which can not only effectively solve the problem of bubble entrapment, but also improve the stability and efficiency of the coating process, thereby improving the coating efficiency and reducing bubble entrapment.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present invention 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 plate and a downstream guide plate; the first coating module, the upstream gasket, the central gasket, the downstream gasket and the second coating module are fixed together in sequence from left to right, the upper part of the upstream guide plate is fixedly connected to the lower part of the upstream gasket, and the upper part of the downstream guide plate is fixedly connected to the lower part of the downstream gasket;

[0007] An arc-shaped manifold is provided on 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 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] The outer wall of the second coating module is provided with a liquid inlet;

[0010] The inner wall of the second coating module is provided with an arc-shaped manifold, and an inclined flow channel is connected below the manifold; the manifold is connected with the liquid inlet;

[0011] The downstream gasket is provided with an inverted U-shaped groove, the top 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] An inverted U-shaped groove is formed at the bottom of the central gasket, the top 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, the upstream gasket is provided with rectangular grooves at the front and rear sides of the bottom end respectively; the upstream guide plate comprises a rectangular connecting plate, an arc plate and a horizontal plate, the rectangular connecting plate has two pieces, which are respectively 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, and the length h2 is greater than the length h1 of the rectangular groove provided at the bottom end of the upstream gasket;

[0014] The downstream gasket has rectangular grooves on the front and rear sides of the bottom end respectively; the downstream guide plate includes a rectangular connecting plate, an arc plate and a horizontal plate, the rectangular connecting plate has two pieces, which are respectively 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 d4 of the rectangular connecting plate is consistent with the width d3 of the rectangular groove opened at the bottom end of the downstream gasket, and the length h4 is greater than the length h3 of the rectangular groove opened at the bottom end of the downstream gasket.

[0015] Furthermore, the first coating module, the upstream gasket, the central gasket, the downstream gasket and the second coating module are fixedly connected in sequence by bolts.

[0016] Furthermore, the thickness w2 of the upstream guide plate is greater than the thickness w1 of the upstream gasket, and is an interference fit, and is locked by friction during the installation process; the thickness w4 of the downstream guide plate is greater than the thickness w3 of the downstream gasket, and is an interference fit, and is locked by friction during the installation process.

[0017] Furthermore, the size of the upstream guide plate is selected according to the properties of the coating liquid and the coating substrate; the size of the downstream guide plate is selected according to the properties of the coating liquid and the coating substrate.

[0018] Furthermore, the surface of the upstream guide vane has millimeter-scale micro grooves with an array length-to-width ratio of 1:2; the surface of the downstream guide vane has an array of micro grooves.

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

[0020] 1. When the present invention is coating the product, the upstream guide vane and the downstream guide vane can stabilize the upstream meniscus without destroying the overall flow, destroy the vortex appearing on the contact surface between the upstream meniscus and the substrate, and reduce the involvement of bubbles. This ensures the surface quality of the film and achieves stable and efficient coating.

[0021] 2. The presence of arrays of micro grooves on the surfaces of the upstream guide vane and the downstream guide vane of the present invention can ensure the stability of the flow and further improve the preparation efficiency.

[0022] 3. The flat plates at the bottom of the upstream guide vane and the downstream guide vane of the present invention can equivalently adjust the blade height, dividing the downstream coating process into multiple coating processes with low blade heights, which is helpful for flow stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention (explosion diagram);

[0024] Figure 2 for Figure 1 Schematic cross-sectional view of ;

[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 in conjunction with the accompanying drawings.

[0028] like Figure 1-3 As shown, a slit coating slot die head for improving coating efficiency and reducing bubble entrapment 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 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 below the manifold of the first coating module 1;

[0031] The outer wall of the second coating module 2 is provided with a liquid inlet;

[0032] 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;

[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] An inverted U-shaped groove is formed at the bottom of the central gasket 5 , 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] Furthermore, the upstream gasket 4 is provided with rectangular grooves at the front and rear sides of the bottom end respectively; 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 respectively 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;

[0036] The downstream gasket 3 has rectangular grooves on the front and rear sides of the bottom end respectively; the downstream guide plate 7 includes a rectangular connecting plate, an arc plate and a horizontal plate, the rectangular connecting plates have two pieces, which are respectively 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 d4 of the rectangular connecting plate is consistent with the width d3 of the rectangular groove opened at the bottom end of the downstream gasket 3, and the length h4 is greater than the length h3 of the rectangular groove opened at the bottom end of the downstream gasket 3.

[0037] Furthermore, 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.

[0038] Furthermore, the thickness w2 of the upstream guide plate 6 is greater than the thickness w1 of the upstream gasket 4, and an interference fit is provided, and the installation process relies on friction to lock; the thickness w4 of the downstream guide plate 7 is greater than the thickness w3 of the downstream gasket 3, and an interference fit is provided, and the installation process relies on friction to lock.

[0039] Furthermore, 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.

[0040] Furthermore, the surface of the upstream guide vane 6 has millimeter-scale micro grooves with an array length-to-width ratio of 1:2; and the surface of the downstream guide vane 7 has an array of micro grooves.

[0041] The steps of adjusting the guide plate according to the coating material and process of the present invention are as follows:

[0042] First, according to the coating process, substrate wettability and materials used, appropriate upstream guide pieces 6 and downstream guide pieces 7 are selected, and the selected upstream guide pieces 6 and downstream guide pieces 7 are respectively inserted into the rectangular grooves respectively opened on the left and right sides of the bottom of the upstream gasket 4 and the rectangular grooves respectively opened on the left and right sides of the bottom of the downstream gasket 3. Afterwards, 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 with bolts, and the upstream guide piece 6 and the downstream guide piece 7 are locked by interference fit.

[0043] The optical liquid glue to be coated flows from the liquid inlet opened on the outer wall of the second coating module 2 into the arc-shaped manifold opened on the inner wall of the first coating module 1 and the arc-shaped manifold opened on the inner wall of the second coating module 2, and then flows into the flow channel below the manifold, and flows into the upstream guide plate 6 and the downstream guide plate 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 guide plate 6 and the downstream guide plate 7, the stability of the flow is guaranteed due to the presence of an array of micro grooves on the surface of the upstream guide plate 6 and the downstream guide plate 7. At the same time, according to research, the bubble entrainment is mainly due to the vortex generated at the contact surface between the upstream meniscus and the substrate. The upstream guide plate 6 and the downstream guide plate 7 can destroy the vortex without changing the overall flow direction, reduce the bubble entrainment, increase the coating speed, and ensure the surface quality of the film.

[0044] As described above, for ordinary technicians in this field, various other corresponding changes and modifications can be made based on the technical solutions and technical concepts of the present invention, and all these changes and modifications should fall within the protection scope of the claims of the present invention.

Claims

1. A slit coating slot die head for improving coating efficiency and reducing bubble entrainment, characterized in that: 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 end of which is in the same shape as the upper end of the manifold of the first coating module (1), and the width of the inverted U-shaped groove is in the same width as the inclined flow channel connected to the lower part of the manifold of the first coating module (1); The second coating module (2) has a liquid inlet on its outer wall; 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 end of which is in the same shape as the upper end of the manifold of the second coating module (2), and the width of the inverted U-shaped groove is in the same width as 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 in the same shape as the upper end of the manifold of the first coating module (1), and the width of the inverted U-shaped groove is in the same width as the inclined flow channel connected below the manifold of the first coating module (1).

2. According to claim 1, a slit coating slot die head for improving coating efficiency and reducing bubble entrapment, characterized in that: The upstream gasket (4) is provided with rectangular grooves at the front and rear sides of the bottom end respectively; 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 respectively 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 at 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 respectively 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 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).

3. According to claim 1, a slit coating slot die head for improving coating efficiency and reducing bubble entrapment, 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.

4. According to claim 1, a slit coating slot die head for improving coating efficiency and reducing bubble entrapment, 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.

5. A slit coating slot 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.

6. A 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 vane (6) has micro grooves of the order of millimeters with an array length-to-width ratio of 1:2; the surface of the downstream guide vane (7) has micro grooves of the order of millimeters.

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