TW201617142A - Device for film casting - Google Patents

Abstract

The invention relates to a method for producing a film (11) and to a device (1) for film casting comprising at least one continuous belt (2) which circulates between at least one drive roller (3) and at least one deflection roller (4), an upper strand of the continuous belt (2) being housed at least in sections by means of a drying tunnel (5), and when seen in the direction of circulation of the continuous belt (2), at least one casting device (7) for applying a film on an outer surface of the continuous belt (2) is arranged upstream of the drying tunnel (5) housed at least in sections in the upper strand, a lower strand of the continuous belt (2) is housed at least in sections by means of a drying tunnel (6).

Description

Cast film device

The present invention relates to a device for casting a film, comprising at least one endless belt, which is rotated between at least one driving drum and at least one steering drum, wherein the returning section above the annulus is at least partially dried by a tunnel Surrounding, and, in the direction of rotation of the annulus, at least one casting device for coating the film to the outer surface of the annulus is disposed in front of the drying tunnel that at least partially surrounds the upper return section.

The invention also relates to a method of making a film.

Devices of the type described in the opening paragraph are used for the production of films, in particular polyvinyl alcohol films (PVOH films). Among them, as a processing belt for coating and transporting a film, the endless belt is wound between the driving drum and the steering drum, and is tensioned between the driving drum and the steering drum.

When a device of the type described in the opening paragraph is used, the turn of the drum causes a nearly 180° turn of the annulus. The upper row segment and the next segment segment are substantially parallel to each other. The upper return line constitutes a bearing surface and/or a transport surface for the medium, for example in a liquid state, and is applied to a movable belt that is rotated between the drive drum and the steering drum, the belt being for example metal production.

The return section above the annulus is typically passed through a dry tunnel for drying the film. In this drying tunnel, a number of heating elements are usually arranged on one side of the surface of the annulus coated with the film. The film is usually peeled off from the upper row after passing through the drying tunnel.

A primary disadvantage of the conventional embodiment is that a very large overall length is usually required in order to achieve a sufficiently long drying section for the film. Cannot be implemented due to space or cost reasons Longer dry tunnels may require stripping of the still relatively wet film from the upper row, which in turn creates a greater risk of film damage.

In view of the above, it is an object of the present invention to overcome the above disadvantages of the prior art.

The solution of the invention to achieve the above object is a device of the type described in the opening paragraph, wherein the return section below the annulus is at least partially surrounded by a dry tunnel.

According to the solution of the present invention, it is possible to peel off a film having a low humidity (solvent content) while shortening the total length of the device, thereby greatly reducing the risk of damage of the film.

In order to make contact with the next return line segment as needed, for example to carry out a cleaning or maintenance operation, the dry tunnel at least partially surrounding the next return line segment may have at least one door, the opening direction of the door being from the outer surface of the endless belt In addition, the outer surface of the annulus can be accessed by opening the door.

In order to peel off the film which is as dry as possible, in the direction of rotation of the annulus, it is preferred to arrange a stripping device, in particular a peeling roller, after the drying tunnel which at least partially surrounds the lower return section, in order to The return section of the loop is peeled off.

Another solution of the invention to achieve the above object is a method of the type described in the opening paragraph, wherein in step i) the coating nozzle of the casting device and the outer surface of the annulus are in some manner The distance is adjusted so that when the film is subsequently applied to the outer surface of the annulus by the coating nozzle in step ii) to form the film, the accumulation of the material is formed in the coating nozzle, and the coating nozzle and The space between the coating nozzle and the outer surface of the annulus is completely filled with the material.

By the method of the present invention, uniform coating of the material can be achieved from the beginning of the casting process. Compared to the solutions known in the prior art, the present invention is capable of preventing uneven coating of materials at the beginning of the casting process, thereby preventing irregularities in the film. Uneven coating of materials as known in the prior art results in the need to return the film to the film under the loop The starting area is scraped. Therefore, there is a big problem in the conventional manufacturing method because it is necessary to carry out the above operation in a continuous process. In addition, in the conventional solution, it is necessary to be able to freely touch the next line segment in order to scrape the film, so that it is impossible to surround the next line segment in the conventional solution. The idea of the method of the invention is such that the distance between the casting device and the surface of the annulus is as small as possible, so that the material is reflowed at the beginning of the casting process, thereby achieving a very uniform film from the beginning of the casting process. . Therefore, when the method of the present invention is employed, it is preferred to use the apparatus of any one of claims 1 to 4.

In order to achieve a uniform coating of the material and a uniform thickness of the film, the loop can be moved further in the direction of rotation without interruption during at least step ii).

The front end of the film can be easily and reliably peeled off from the endless belt by: at least before step ii), placing a film on the outer surface of the endless belt is firstly carried out in step ii) On the section of the coating material.

After the material is applied to the film, the material is preferably applied directly to the outer surface of the annulus. According to this aspect of the invention, only at the beginning of the casting process, the membrane is placed in a region corresponding to the front end of the film in the direction of rotation of the annulus, and, as is conventional, Subsequent areas of the film are cast directly onto the surface of the annulus. The advantage of this solution is that the film can be reliably peeled off with very low cost and production time.

According to one aspect of the invention for optimally utilizing the processing length for film drying, in step iii), after passing through the drying tunnel which at least partially surrounds the return section below the loop, the film is first applied The sheet is peeled from the outer surface of the annulus by means of a surface that is removed from the outer surface of the annulus.

1‧‧‧ device

2‧‧‧环带

3‧‧‧Drive roller

4‧‧‧Steering drum

5‧‧‧Dry tunnel

6‧‧‧Dry tunnel

7‧‧‧ casting device

8‧‧‧ peeling roller

9‧‧‧Applicator mouth

10‧‧‧

11‧‧‧

12‧‧‧ Film

13‧‧‧Materials

14‧‧‧ diaphragm

15‧‧‧ outer surface

Figure 1 is a view of the apparatus of the present invention; Figure 2 is a cross-sectional view of the drying tunnel of the apparatus of Figure 1 surrounded by a lower return section; Figure 3 is a cross-sectional view of the coating nozzle of the casting apparatus in the case of a running direction transverse to the belt of the apparatus shown in Figure 1; and Figure 4 is a section of the belt of the apparatus of Figure 1. Top view.

For ease of understanding, the present invention will be further described below in conjunction with the accompanying drawings.

In the different embodiments, the same components are denoted by the same reference numerals and the same component names, and all the disclosures contained in the specification are applicable to the same components having the same symbols or the same component names as appropriate. The descriptions of the orientations selected in the manual are related to the related drawings as above, below, and on the side, and the orientation is changed as appropriate for the new orientation. Moreover, the individual features or combinations of features included in the various embodiments illustrated and described form a stand-alone solution, an innovative solution, or a solution in accordance with the present invention.

For the purpose of specific description, all descriptions relating to the range should be understood to include any and all sub-domains. For example, "1 to 10" should be understood to include all sub-domains from the lower limit 1 to the upper limit 10 Within, that is, all sub-domains start at a lower limit of 1 or greater than 1, and terminate at an upper limit of 10 or less than 10, such as 1 to 1.7 or 3.2 to 8.1 or 5.5 to 10.

As shown in FIG. 1, the apparatus 1 for casting film of the present invention has an endless belt 2 that is rotated between a driving drum 3 and a steering drum 4. The device 1 is preferably a PVOH film casting device. The return section above the annulus 2 is surrounded by a drying tunnel 5. Viewed in the direction of rotation of the annulus 2, a conventional casting device 7 is arranged in front of the drying tunnel 5 for applying the film to the outer surface of the annulus 2 (indicated by symbol 15 in Figure 4). The direction of rotation of the annulus 2 is shown by arrows in Figure 1.

According to the invention, the return section below the annulus 2 is also surrounded by the drying tunnel 6. Although the upper row and the next row are respectively surrounded by the own drying tunnels 5, 6 in the illustrated embodiment, according to another aspect of the invention, a separate one will be provided and the upper row and the lower row. A dry tunnel surrounded by a return section.

As shown in FIG. 2, the drying tunnel 6 can have one or more doors 10, 11. The opening directions of the doors 10, 11 are outward from the outer surface 15, so that the ring belt 2 can be accessed by opening the doors 10, 11. Outer surface 15.

A peeling device 8, such as a peeling roller, may be disposed after the drying tunnel 6 to peel the film 12 from the return section below the endless belt 2.

The device 1 is particularly suitable for carrying out the method of the invention.

As shown in Fig. 3, according to the invention, the distance between the coating nozzle 9 of the casting device 7 and the outer surface 15 of the annulus 2 is adjusted in a certain manner in step i) such that it is subsequently passed through in step ii) When the coating nozzle 9 applies the material 13 to the outer surface 15 of the endless belt 2 to form the film 12, the accumulation of the constituent material 13 in the coating nozzle 9 and the coating nozzle 9 and the coating nozzle 9 and the ring are formed. The space between the outer surfaces 15 of the belt 2 is completely filled with the material 13.

During the coating of the material 13 in step ii), the annulus 2 can be moved further in the direction of rotation without interruption, so that a uniform distribution of the film 12 is achieved.

As shown in Figure 4, the membrane 14 can be placed onto the section of the outer surface 15 of the annulus 2 at least prior to step ii), i.e., prior to application of the material. After laying the membrane 14, the material 13 can be applied to the membrane and the annulus 2 can be moved further to directly coat the material 13 of the surface 15 of the annulus 2 behind the membrane 14. The area of the surface 15 covered by the film 14 corresponds to the front end of the film 12, which is first peeled off from the endless belt 2 by the peeling device 8.

The peeled film 12 can be wound into a roll or conveyed to a subsequent processing step. Finally, it should be noted that, in order to better understand the structure of the device of the present invention, the device and its components are not shown to be proportioned and/or enlarged and/or reduced.

1‧‧‧ device

2‧‧‧环带

3‧‧‧Drive roller

4‧‧‧Steering drum

5‧‧‧Dry tunnel

6‧‧‧Dry tunnel

7‧‧‧ casting device

8‧‧‧ peeling roller

12‧‧‧ Film

Claims (9)

A casting device (1) comprising at least one endless belt (2), which is rotated between at least one driving drum (3) and at least one steering drum (4), wherein the belt (2) is above The return section is at least partially surrounded by the drying tunnel (5) and, as viewed in the direction of rotation of the annulus (2), at least partially arranged before the drying tunnel (5) surrounding the upper return section A casting device (7) for applying a film to the outer surface (15) of the annulus (2), characterized in that the return section below the annulus (2) is at least partially dried by a tunnel (6) Surrounded by. The device of claim 1, wherein the drying tunnel (6) at least partially surrounding the lower row segment has at least one door (10, 11), and the opening direction of the door is from the ring belt (2) The outer surface (15) faces outward, so that the outer surface (15) of the endless belt (2) can be accessed by opening the door. A device according to claim 1 or 2, characterized in that, in the direction of rotation of the annulus (2), a stripping device is arranged after the drying tunnel (6) which at least partially surrounds the lower return section (8), in particular peeling the drum, in order to peel the film (12) from the return section below the endless belt (2). A method of producing a film (12), characterized in that in step i) the coating nozzle (9) of the casting device (7) and the outer surface (15) of the ring belt (2) are somehow The distance is adjusted such that when the material (13) is subsequently applied to the outer surface (15) of the endless belt (2) through the coating nozzle (9) in step ii) to form the film (12), The accumulation of the material (13) is formed in the coating nozzle (9), and the space between the coating nozzle (9) and the outer surface (15) of the coating nozzle (9) and the annulus (2) is completely The material (13) is filled. The method of claim 4, characterized in that the endless belt (2) is moved further in the direction of rotation without interruption during at least this step ii). The method of claim 4, wherein the method is at least in the step ii) Previously, the membrane (14) is placed onto the outer surface of the annulus (2) on the section of the first coated material (13) in step ii). The method of claim 6, wherein the material (13) is directly applied to the outer band (2) after the material (13) is applied to the film (14). Surface (15). The method of claim 7, characterized in that in step iii), after passing through the drying tunnel (6) which at least partially surrounds the return section below the annulus (2), the membrane is first applied The sheet (14) is peeled from the outer surface (15) of the endless belt (2) in such a manner that the outer surface (15) of the endless belt (2) is peeled off. The method of any one of claims 4 to 8, which is characterized in that the apparatus of any one of claims 1 to 3 is used.