A kind of cast film stabilizing device, casting device and the manufacturing method of cast film

Abstract

The present application relates to C08J, more particularly, the present application relates to a kind of cast film stabilizing device, flow casting device and the production method of cast film.It includes: first windbreak device, second windbreak device.In the flow casting process, the process air from the direction of stretching drying section to flow casting section can be intercepted by the first windbreak device in the form of labyrinth, to avoid direct influence on the film falling process;And the second windbreak device is arranged behind the flow casting die to further avoid the influence of the air from the stretching drying section to the flow casting section on the film falling process, and in order to avoid vortex in the wind field between the die and the windbreak in the flow direction of the die, ventilation guide hole is arranged on the upper part of the second windbreak device, so that the flowing air before and after the die flows from the area far away from the film surface, by the stabilizing device provided by the present application, the flowing air before and after the die where the film flows can be greatly eliminated, and the thickness unevenness of the film surface is improved, and the product quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to C08J, and more particularly, the present application relates to a cast film stabilizing device, a casting device and a method for manufacturing a cast film. BACKGROUND

[0002] The cellulose film made by solution casting method has excellent optical properties and apparent properties, and stable mechanical properties. Among them, in the process of making cellulose film by solution casting method, as shown in CN107650313A, cellulose solution is prepared by dissolving and mixing equipment, continuously and uniformly cast to a mirror surface ring belt support body of stainless steel material through a casting die, peeled off from the support body after drying, and further stretched, dried and wound, to finally form a cast film.

[0003] When the cellulose film is used for display film such as TAC film for polarizing plate, in order to ensure the display performance, the overall thickness uniformity of the film has strict difference requirements, and the control of thickness and uniformity in the casting process is very important. The casting process is that the cellulose solution flows out through the gap of the die, forms a cast film, and falls by gravity to the support body. The die discharge flow and the running speed of the support body are matched in different degrees to control the thickness of the cast film. In the above process, the running direction uniformity of the film thickness is affected by the pulsatility of the discharge flow, which can be solved by adding a non-pulsatile pump. In addition to the above factors, the cast film is also affected by the surrounding wind field during the process of falling by gravity, causing the time difference of the transverse film layer falling, thereby affecting the uniform contact of the cast film with the support body, and finally reflecting the uniformity difference of the film, mainly characterized by transverse lines and unevenness. In addition, due to the tension characteristics of the cast film body between the die and the support body, the wind field force is easy to produce breathing effect in the process of falling film, which aggravates the malady of transverse lines on the film surface.

[0004] Therefore, the main control method for the surrounding wind field of the casting die is to adjust the surrounding process air pressure to achieve a windless or zero pressure state as much as possible, which is difficult to achieve in a large process production environment. Another conventional measure is to set a wind shield device around the die, because the film and the support body are in running state, the wind shield cannot achieve complete wind blocking effect, at the same time causing turbulent flow of the wind field inside the shield, which aggravates the instability of the falling film. In addition, other negative pressure devices are used in front of the die to control the flow direction of the falling film surrounding wind field, but it is easy to cause drying aggravation effect for the cast film, which destroys the film process environment and causes the film to appear excessive warping and other maladies. SUMMARY

[0005] In order to solve the above problems, the present invention provides a method for stabilizing the wind field around the die head, and the method can effectively solve the problem that the wind field affects the film falling process. The surface uniformity and surface flatness of the product are good. The first aspect of the present invention provides a cast film stabilizing device, comprising a first windshield and a second windshield. When the solution is cast through the die head, along the casting direction, the first windshield is located at the front of the die head, and the second windshield is located at the rear of the die head. The front and rear parts along the casting direction mean that the part that passes through first is the front part, and the part that passes through later is the rear part, that is, after the casting liquid comes out of the die head, it passes through the second windshield, so it is the rear part, and because the first windshield is before the casting liquid comes out, it is the front part.

[0006] As a preferred technical solution of the present invention, the first windshield is composed of stacked windshields, with grooves formed at the lower ends of the N-1th, Nth, and N+1th windshields, forming a multi-layered structure with varying heights at the lower end of the first windshield. The stacked windshields, i.e., the Nth windshield is flanked by the N-1th and N+1th windshields, respectively.

[0007] As a preferred technical solution of the present invention, Figure 2 As shown, the ratio of the depth H of the groove to the width of the groove W is 1-3:1, and the following ratios are listed: 1:1, 1.5:1, 2:1, 2.5:1, and 3:1.

[0008] As a preferred technical solution of the present invention, the number of layers of the windshield is 3-10, preferably 5-7.

[0009] As a preferred technical solution of the present invention, the closest distance between the first windshield device and the solution discharge point of the die head is 10-150 mm, that is, the distance between the position of the first windshield device closest to the solution discharge point of the die head and the discharge point can be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, and 150 mm.

[0010] As a preferred technical solution of the present invention, the first windshield device is arranged perpendicular to the casting direction or at a certain angle. Preferably, the angle between the side surface of the first windshield device close to the die head and the casting direction is 45-90°, preferably 60-90°. Figure 3 Point A in the middle shows the included angle.

[0011] During the film casting die casting process, the surrounding air flow field is affected by multiple drying components, such as Figure 1The first air supply port, first air return port, second air supply port, and second air return port shown in the figure work together to form an unstable wind field. This causes the solution to drift in landing point, a nonlinear phenomenon, from discharge from the die head to contact with the support. This results in localized stretching or accumulation of the film, resulting in poor thickness uniformity and uneven film quality, such as horizontal and vertical striations. The first windshield device of the present invention utilizes a multi-layer windshield to effectively prevent the airflow from the stretching section to the casting section from adversely affecting the die head film landing, thereby ensuring film landing stability.

[0012] As a preferred technical solution of the present invention, a plurality of guide holes are provided on the upper portion of the second windshield device. The guide holes are selected from at least one of circular holes, polygonal holes, and fan-shaped holes, such as elongated holes, circular holes, square holes, and hexagonal holes, preferably elongated holes. The guide holes may also be called ventilation holes.

[0013] As a preferred technical solution of the present invention, the second windshield device is a plate-like structure, and is arranged orthogonally to the casting direction. Preferably, the thickness of the second windshield device is 50-150 mm, preferably 100-150 mm.

[0014] As a preferred technical solution of the present invention, the total area of ​​the guide holes accounts for 30-50% of the total area of ​​the second windshield device, preferably 45-50%.

[0015] As a preferred technical solution of the present invention, the distance between the lowest point of the guide hole and the highest point of the die is 10-500mm, preferably 10-50mm, the lowest point of the guide hole is the edge of the guide hole at the lowest position of the second wind shield device, that is, the horizontal height of the guide hole from the nearest edge of the support body in the casting device, the highest point of the die is the edge point with the highest position of the die, that is, the horizontal height of the die from the farthest edge of the support body in the casting device, and the distance between the lowest point of the guide hole and the highest point of the die is also the distance between the horizontal heights of the lowest point of the guide hole and the highest point of the die.

[0016] During the die film falling process, the surrounding air flow field is affected by the drying components composed of multiple air supply and return ports, such as Figure 1The first air supply port, the first air return port, the second air supply port, and the second air return port shown in the figure work together to form an unstable wind field. Among them, after the gas flowing from the stretching section to the casting section passes through the first windshield device and the die head, it is affected by the support body to form a gas vortex and turbulence in the casting direction area of ​​the die head. In order to avoid the direct effect of the airflow flowing from the casting section to the stretching section on the film landing point of the die head, a second windshield device is arranged. However, when a simple windshield is used as the second windshield device, it will aggravate the gas vortex and turbulence state, thereby causing the film landing point to drift, which is a nonlinear situation. It causes local stretching or accumulation of the film, thereby forming a situation with poor thickness uniformity, and producing problems such as horizontal and vertical stripes on the uneven film quality products. The present invention arranges guide holes on the upper part of the second windshield device, so that the air from the casting section and the stretching section can circulate through the guide holes, thereby avoiding the accumulation of airflow in the casting direction area of ​​the die head and ensuring the stability of the gas flow direction in this area.

[0017] A second aspect of the present invention provides a casting device comprising:

[0018] A support body, both sides of which are tensioned by a rotating drum; the support body is an annular belt-shaped support body;

[0019] a die head, located above one side of the support body;

[0020] The cast film stabilizing device as described above is located above the support body.

[0021] As a preferred technical solution of the present invention, the cross-sectional lower end shape of the first windshield device is consistent with the shape of the portion of the first windshield device projected onto the support body. If the projected portion is an arc, the cross-sectional lower end shape is an arc; if the projected portion is a straight line, the cross-sectional lower end shape is a straight line. Due to the presence of the grooves, the first windshield device forms a multi-layered structure with staggered heights, similar to a maze structure.

[0022] As a preferred technical solution of the present invention, the distance between the lower end of the first windshield device and the support body is 0.5-1 times the distance between the die head and the support body. The distance between the die head and the support body is the distance between the lowest point of the die head and the support body, excluding the distance of the groove part, that is, the lower end of the windshield is in a concave-convex form, and the distance is the spacing between the convex part and the support body. The distance between the lower end of the first windshield device and the support body is the distance between the lower end of the first windshield device and the projection position of the lower end of the first windshield device in the support body. Because the corresponding projection positions of the first windshield device and the support body are consistent in shape, that is, the distance between each point of the lower end of the first windshield device and the support body is consistent, preferably, the distance between the lower end of the first windshield device and the support body is 0.5-2mm.

[0023] As a preferred technical solution of the present invention, the distance between the second windshield device and the support body is 1-10 mm, preferably 1-2 mm, and the distance between the second windshield device and the support body is the distance between the edge of the second windshield device closest to the support body and the support body.

[0024] As a preferred technical solution of the present invention, the horizontal height of the ventilation holes from the nearest edge of the support body is 10-500 mm higher than the highest point of the die head, preferably 10-50 mm.

[0025] As a preferred technical solution of the present invention, the casting apparatus further includes a drying assembly located outside the support body. The drying assembly is composed of a plurality of return air inlets and air supply inlets, which are not specifically limited and can be selected according to the casting process. As an example, along the casting direction, the drying assembly includes, in sequence, a first air supply inlet, a first return air inlet, a second air supply inlet, a second return air inlet, a third return air inlet, and a third air supply inlet; along the casting direction, the drying assembly is located behind the second windshield device; the casting direction is also the direction of rotation of the support body.

[0026] The third aspect of the present invention provides a method for producing a cast film, comprising: using a casting device containing a cast film stabilizing device to perform casting to obtain the cast film.

[0027] As a preferred technical solution of the present invention, the production method includes: the solution is continuously cast through the die to form a cast film, and after drying along with the support body, it is peeled off from the support body and enters the stretching and drying process, and finally rolled up to obtain the film; the front part of the die head is provided with a first windshield device, and the rear part of the die head is provided with a second windshield device.

[0028] Compared with the prior art, the present invention has the following beneficial effects: during the casting process of the present invention, the process wind flowing from the stretching and drying section to the casting section can be intercepted by a first wind shielding device in a maze form to avoid direct influence on the film falling process; and a second wind shielding device is arranged behind the casting die film flow to further avoid the influence of the wind from the casting section to the stretching and drying section on the film falling process, and in order to avoid the formation of vortexes in the wind field between the die and the die casting direction wind shield, ventilation guide holes are arranged on the upper part of the second wind shielding device, so that the flow wind before and after the die is circulated from the area away from the film surface. The stabilizing device provided by the present invention can greatly eliminate the flow wind before and after the die film flow, and the uneven thickness of the film surface is improved, thereby improving the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 is an overview diagram of a thin film manufacturing method according to an embodiment of the present invention.

[0030] Figure 2 2 is a schematic structural diagram of a first windshield device according to an embodiment of the present invention.

[0031] Figure 3 Schematic diagram of the arrangement of the first windshield device according to an embodiment of the present invention.

[0032] Figure 4 1 is a schematic top view of the arrangement of the first windshield device according to an embodiment of the present invention.

[0033] Figure 5 2 is a schematic structural diagram of a second windshield device according to an embodiment of the present invention.

[0034] Figure 6 Schematic diagram of the arrangement of the second windshield device according to an embodiment of the present invention.

[0035] Figure 7 Schematic diagram of a method for evaluating the quality of a finished film according to an embodiment of the present invention.

[0036] Among them: solution 31, die head 22, support body 23, film 32, first air supply port 41, first air return port 42, second air supply port 43, second air return port 44, third air supply port 46, third air return port 45, peeling roller 32a, first wind shield device 11, second wind shield device 12. DETAILED DESCRIPTION

[0037] Example

[0038] Example 1

[0039] like Figure 1-6 As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 1:1; the number of layers of the windshield is 3, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 150 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 45°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from long strip holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 50 mm, the total area of ​​the guide holes accounts for 35% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 10 mm.

[0040] This example also provides a casting device, comprising:

[0041] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0042] The die head 22 is located above one side of the support body 23;

[0043] The cast film stabilization device as described above is located above the support body 23, and the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23. The distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23. The distance between the second wind shield device 12 and the support body 23 is 1 mm, and the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 10 mm higher than the highest point of the die head 22. The cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0044] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0045] Example 2

[0046] like Figure 1-6As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 3:1; the number of layers of the windshield is 10, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 150 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 90°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from long strip holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 150 mm, the total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 100 mm.

[0047] This example also provides a casting device, comprising:

[0048] A support body, both sides of which are tensioned by a rotating drum; the support body is an annular belt-shaped support body;

[0049] The die head 22 is located above one side of the support body;

[0050] The cast film stabilizing device as described above is located above the support body, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body, the distance between the lower end of the first wind shield device 11 and the support body is 0.5 times the distance between the die head 22 and the support body, the distance between the second wind shield device 12 and the support body is 10 mm, and the horizontal height of the ventilation hole at the nearest edge of the support body is 100 mm higher than the highest point of the die head 22. The cast device also includes a drying component, which is located on the periphery of the support body. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0051] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0052] Example 3

[0053] like Figure 1-6 As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 1.5:1; the number of layers of the windshield is 7, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 100 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 90°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from long strip holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 150 mm, the total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 50 mm.

[0054] This example also provides a casting device, comprising:

[0055] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0056] The die head 22 is located above one side of the support body 23;

[0057] The cast film stabilizing device as described above is located above the support body 23, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23, the distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23, the distance between the second wind shield device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, the cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0058] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0059] Example 4

[0060] like Figure 1-6 As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 1.5:1; the number of layers of the windshield is 7, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 150 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 90°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from long strip holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 150 mm, the total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 50 mm.

[0061] This example also provides a casting device, comprising:

[0062] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0063] The die head 22 is located above one side of the support body 23;

[0064] The cast film stabilizing device as described above is located above the support body 23, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23, the distance between the lower end of the first wind shield device 11 and the support body 23 is 1 times the distance between the die head 22 and the support body 23, the distance between the second wind shield device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, the cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0065] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0066] Example 5

[0067] like Figure 1-6As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 1.5:1; the number of layers of the windshield is 7, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 150 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 90°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from long strip holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 150 mm, the total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 50 mm.

[0068] This example also provides a casting device, comprising:

[0069] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0070] The die head 22 is located above one side of the support body 23;

[0071] The cast film stabilizing device as described above is located above the support body 23, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23, the distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23, the distance between the second wind shield device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, the cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0072] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0073] Example 6

[0074] like Figure 1-6 As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 1.5:1; the number of layers of the windshield is 7, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 150 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 45°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from circular holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 150 mm, the total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 50 mm.

[0075] This example also provides a casting device, comprising:

[0076] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0077] The die head 22 is located above one side of the support body 23;

[0078] The cast film stabilizing device as described above is located above the support body 23, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23, the distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23, the distance between the second wind shield device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, the cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0079] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0080] Example 7

[0081] like Figure 1-6 As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 1.5:1; the number of layers of the windshield is 7, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 150 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 90°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from square holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 150 mm, the total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 50 mm.

[0082] This example also provides a casting device, comprising:

[0083] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0084] The die head 22 is located above one side of the support body 23;

[0085] The cast film stabilizing device as described above is located above the support body 23, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23, the distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23, the distance between the second wind shield device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, the cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0086] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0087] Example 8

[0088] like Figure 1-6As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11 and a second windshield 12. When a solution is cast through a die 22, along the casting direction, the first windshield 11 is located in front of the die 22, and the second windshield 12 is located behind the die 22. The first windshield 11 is composed of stacked windshields. The windshields of the N-1 layer, the N layer, and the N+1 layer are grooved at their lower ends, forming a multi-layered structure with different heights at the lower end of the first windshield 11. The ratio of the depth H of the groove to the width of the groove W is 1.5:1; the number of layers of the windshield is 7, the closest distance between the first windshield device 11 and the solution discharge point of the die head 22 is 150 mm, the angle between the side surface of the first windshield device 11 close to the die head 22 and the casting direction is 90°, a plurality of guide holes are provided on the upper part of the second windshield device 12, the guide holes are selected from circular holes, the second windshield device 12 is a plate-like structure, and is arranged orthogonally to the casting direction, the thickness of the second windshield device 12 is 150 mm, the total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield device 12, and the distance between the lowest point of the guide hole and the highest point of the die head 22 is 50 mm.

[0089] This example also provides a casting device, comprising:

[0090] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0091] The die head 22 is located above one side of the support body 23;

[0092] The cast film stabilizing device as described above is located above the support body 23, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23, the distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23, the distance between the second wind shield device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, the cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0093] The example also provides a method for manufacturing a cast film, comprising: using a casting device containing a cast film stabilizing device to cast, casting solution 31 through die 22 onto support 23 to produce film 32, at this time the thickness of film 32 is 100 microns. Film 32 is transported with support 22, after primary drying by first air supply port 41 and first return air port 42, secondary drying by second air supply port 43 and second return air port 44, and finally final drying by third air supply port 46 and third return air port 45, the thickness is reduced to 80 microns, after stripping by stripping roller 32a, it enters the stretching, drying and winding process, and a standard film product is obtained.

[0094] Example 9

[0095] As shown in Figure 1-6 The example provides a cast film stabilizing device, comprising a first wind blocking device 11 and a second wind blocking device 12, when the solution is cast through die 22, along the casting direction, the first wind blocking device 11 is located in front of the die 22, and the second wind blocking device 12 is located behind the die 22. The first wind blocking device 11 is composed of stacked wind blocking plates, the lower ends of the N-1th, Nth and N+1th wind blocking plates form grooves, so that the lower end of the first wind blocking device 11 forms a staggered multi-layer structure. The depth H of the groove and the width W of the groove are in a ratio of 1.5:1; the number of layers of the wind blocking plate is 7, the closest distance from the die 22 to the solution discharge point of the first wind blocking device 11 is 150 mm, the angle between the side surface of the first wind blocking device 11 close to the die 22 and the casting direction is 90°, the upper part of the second wind blocking device 12 is provided with a plurality of guide holes, the guide holes are selected from round holes, the second wind blocking device 12 is a plate structure and is arranged perpendicular to the casting direction, the thickness of the second wind blocking device 12 is 150 mm, the total area of the guide holes accounts for 50% of the total area of the second wind blocking device 12, and the distance between the lowest point of the guide hole and the highest point of the die 22 is 50 mm.

[0096] The example also provides a casting device, comprising:

[0097] Support 23, both sides of the support 23 are tensioned by a rotating drum; the support 23 is an annular belt-shaped support 23;

[0098] Die 22, located above one side of support 23;

[0099] The cast film stabilizing device as described above is located above the support body 23, the shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23, the distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23, the distance between the second wind shield device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, the cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0100] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 220 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 200 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0101] Comparative Example 1

[0102] This example provides a method for producing a cast film, comprising: using a casting apparatus including a cast film stabilizer to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32 having a thickness of 150 microns. The film 32 rotates along the support 22, undergoing initial drying via a first air supply port 41 and a first air return port 42, secondary drying via a second air supply port 43 and a second air return port 44, and final drying via a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. The film is then stripped by a stripping roller 32a and subjected to stretching, drying, and winding steps to produce a standard film product. This does not include a stabilization device.

[0103] Comparative Example 2

[0104] like Figure 1-6As shown, this embodiment provides a cast film stabilization device, comprising a first windshield 11. When the solution is cast through the die head 22, along the casting direction, the first windshield 11 is located in front of the die head 22, and the second windshield 12 is located behind the die head 22. The first windshield 11 is composed of stacked windshields. The lower ends of the N-1 windshield, the Nth windshield, and the N+1 windshield form grooves, forming a multi-layered structure with staggered heights at the lower end of the first windshield 11. The ratio of the groove depth H to the groove width W is 1.5:1; the number of windshields is 7. The closest distance between the first windshield 11 and the solution discharge point of the die head 22 is 150 mm, and the angle between the side surface of the first windshield 11 close to the die head 22 and the casting direction is 90°.

[0105] This example also provides a casting device, comprising:

[0106] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0107] The die head 22 is located above one side of the support body 23;

[0108] The cast film stabilizing device as described above is located above the support body 23. The shape of the lower end of the cross section of the first wind shield device 11 is consistent with the shape of the part of the first wind shield device 11 projected onto the support body 23. The distance between the lower end of the first wind shield device 11 and the support body 23 is 0.5 times the distance between the die head 22 and the support body 23. The cast device also includes a drying component, which is located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first return air port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0109] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0110] Comparative Example 3

[0111] like Figure 1-6As shown, this embodiment provides a cast film stabilization device, comprising a second windshield 12. When the solution is cast through a die head 22, the second windshield 12 is located behind the die head 22 along the casting direction. A plurality of guide holes are provided on the upper portion of the second windshield 12. The guide holes are selected from the following: the second windshield 12 is a plate-like structure arranged orthogonally to the casting direction. The second windshield 12 has a thickness of 150 mm. The total area of ​​the guide holes accounts for 50% of the total area of ​​the second windshield 12. The distance between the lowest point of the guide holes and the highest point of the die head 22 is 50 mm.

[0112] This example also provides a casting device, comprising:

[0113] A support body 23, both sides of which are tensioned by a rotating drum; the support body 23 is an annular belt-shaped support body 23;

[0114] The die head 22 is located above one side of the support body 23;

[0115] The cast film stabilizing device as described above is located above the support body 23, the distance between the second wind shielding device 12 and the support body 23 is 1 mm, the horizontal height of the ventilation hole at the nearest edge of the support body 23 is 50 mm higher than the highest point of the die head 22, and the cast device also includes a drying component located on the periphery of the support body 23. Along the casting direction, the drying component includes a first air supply port 41, a first air return port 42, a second air supply port 43, a second return air port 44, a third air supply port 46, and a third return air port 45 in sequence.

[0116] This example also provides a method for producing a cast film, comprising: using a casting device including a cast film stabilizing device to cast a solution 31 through a die head 22 onto a support 23 to produce a film 32, wherein the film 32 has a thickness of 150 microns. The film 32 rotates along the support 22, undergoes initial drying by a first air supply port 41 and a first air return port 42, undergoes secondary drying by a second air supply port 43 and a second air return port 44, and finally undergoes final drying by a third air supply port 46 and a third air return port 45, reducing the thickness to 130 microns. After being stripped by a stripping roller 32a, the film 32 enters a stretching, drying, and winding process to produce a standard film product.

[0117] Performance evaluation

[0118] For the film products obtained in the examples, single-layer films of a certain size were taken as samples and the following method was used to evaluate the quality of the transverse stripes and wavy film surface. The evaluation results are shown in Table 1.

[0119] 1. Horizontal stripes

[0120] refer to Figure 7Sample 36 is evaluated for horizontal streaks. First, prepare a bracket 51 to secure one edge of sample 35, perpendicular to the casting direction. Secure it with a fixing plate 53, which presses or clamps it. Place a fluorescent tube 52 above bracket 51. The tube's length must be greater than the width of the product 35. The fluorescent tube 52 is 1 meter above the fixing plate and parallel to the secured edge of sample 35. The bracket is 1-1.2 meters above the ground, where a dark velvet cloth 54 is laid. Inspector P stands 1-1.5 meters from the bracket. They grasp the two corners of the sample with both hands and level the sample, observing the reflected light 57 from the fluorescent tube 52 in sample 35 horizontally. Personnel P holds sample 35 taut and swings it up and down through an angle β. During this swinging process, if sample 35 exhibits horizontal streaks, the reflected light 57 will show deformation, primarily characterized by changes in thickness. Within a given width of sample 35, the number of changes in the reflected light 57 serves as the evaluation criterion. Typically, the width is 100 mm.

[0121] The evaluation criteria are:

[0122] A: 0;

[0123] B: 1-10;

[0124] C:>10.

[0125] 2.Wavy membrane surface

[0126] refer to Figure 7 The horizontal stripe quality evaluation was performed on sample 35. The evaluation device and operation process were the same as those for the horizontal stripe.

[0127] The evaluation criteria are to observe the linearity of the reflected light 55 from the fluorescent lamp 52 on the sample 36. The evaluation criteria are whether the linearity of the reflected light 55 is continuous, intermittent, or cannot form an image.

[0128] A: continuous;

[0129] B: intermittent;

[0130] C: Unable to form an image.

[0131] 3. The comprehensive quality assessment results are based on the poorer rating in the horizontal stripes and wavy film surface tests.

[0132] Table 1

[0133] thickness Horizontal stripes Membrane surface unevenness Comprehensive quality assessment Example 1 130 B B B Example 2 130 B B B Example 3 130 A A A Example 4 130 B A B Example 5 130 A A A Example 6 130 A B B Example 7 130 A B B Example 8 80 A A A Example 9 200 A A A Comparative Example 1 130 C C C Comparative Example 2 130 B C C Comparative Example 3 130 C B C

[0134] As can be seen from the test results in the table, the stabilizing device provided by the present invention is beneficial to achieving qualified test results for horizontal stripes and uneven film surface when preparing films by the solution casting method, thereby improving the quality of film products for use as various display films.

Claims

1. A cast film stabilizing device, characterized in that: include: A first windshield device, the first windshield device is composed of stacked windshields, wherein grooves are formed at the lower ends of the N-1 layer of windshields, the N layer of windshields, and the N+1 layer of windshields, so that the lower end of the first windshield device forms a multi-layer structure with staggered heights; a second windshield device, wherein a plurality of guide holes are provided on an upper portion of the second windshield device; When the solution is cast through the die, along the casting direction, the first windshield device is located in front of the die, and the second windshield device is located at the rear of the die; The ratio of the depth H of the groove to the width W of the groove is 1-3:1, and the number of layers of the windshield is 3-10; The first windshield device is at a closest distance of 10-150 mm from the solution discharge point of the die head, and the angle between the side surface of the first windshield device close to the die head and the casting direction is 45-90°; The total area of ​​the guide holes accounts for 30-50% of the total area of ​​the second windshield device, and the horizontal height distance between the lowest point of the guide holes and the highest point of the die head is 10-500 mm.

2. The cast film stabilizing device according to claim 1, characterized in that: The guide hole is selected from at least one of a circular hole, a polygonal hole, and a fan-shaped hole.

3. A casting device, characterized in that include: Support body; a die head, located above one side of the support body; The cast film stabilizing device according to any one of claims 1 to 2 is located above the support.

4. The casting device according to claim 3, characterized in that The shape of the lower end of the cross section of the first windshield device is consistent with the shape of the portion of the first windshield device projected onto the supporting body.

5. The casting device according to claim 3, characterized in that The distance between the lower end of the first wind shielding device and the support body is 0.5-1 times the distance between the die head and the support body.

6. The casting device according to claim 3, characterized in that The distance between the second windshield device and the support body is 1-10 mm, and the distance between the second windshield device and the support body is the distance between the edge of the second windshield device closest to the support body and the support body; The horizontal height of the guide hole from the nearest edge of the support body is 10-500 mm higher than the highest point of the die head, and the casting device also includes a drying component.

7. A method for producing a cast film, characterized in that: include: The casting film is prepared by casting using the casting device containing the casting film stabilizing device according to any one of claims 3 to 6.

Images