Apparatus and method for laminating a substrate with a thermoplastic film

Abstract

The present invention relates to an apparatus (1) for laminating a substrate (12) with a thermoplastic film (11), said apparatus (1) comprising: a laminating unit (2) for laminating a substrate (12) with the thermoplastic film (11); a feeding device (4) for feeding the thermoplastic film (11) to the laminating unit (2), wherein the feeding device (4) for the thermoplastic film (11) comprises a heating device (14) for a first side (16) of the film (11) and a cooling device (15) for a second side (17) of the film (11), as well as a number of controllable driven rollers (10) by which the film (11) is guided to pass through the heating device (14) and the cooling device (15), wherein the tension of the film (11) can be adjusted by the speed of the driven rollers (10).

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for continuously laminating a substrate with a thermoplastic coating material, in particular a film. The substrate may be a film, but may also be a solid made of plastic, metal, or other material. [Background technology]

[0002] Various methods for laminating substrates with thermoplastic films are known. EP 3183117 B1 describes a method and apparatus for joining two film-like substrates, in which at least one film is guided on a conveyor belt through a cooling and heating device in such a way that one side of the film is cooled and the other is heated.

[0003] EP 3526042 B1, by contrast, discloses a similar method in which one film is guided over a cooled roller and subsequently joined to a second film on this roller. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent No. 3183117 [Patent Document 2] European Patent No. 3526042 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it has been found that changes in the length of the thermoplastic film due to gravity or heat can cause problems during feeding and subsequent lamination of the thermoplastic film, particularly creasing and tearing of the film.

[0006] It is therefore an object of the present invention to identify an apparatus and method for laminating a substrate with a thermoplastic film that does not have the aforementioned drawbacks.

[0007] This object is achieved by the subject matter of the independent claims. Advantageous embodiments and developments are the subject matter of the dependent claims. [Means for solving the problem]

[0008] According to one aspect of the present invention, an apparatus for laminating a substrate with a thermoplastic film is provided, the apparatus comprising: a laminating unit for laminating the substrate with the thermoplastic film; and a thermoplastic film supply device for the laminating unit. The thermoplastic film supply device comprises a device for heating a first side of the film and a device for cooling a second side of the film, and a number of controllable driven rollers that guide the film through the heating and cooling devices, and the tension of the film can be adjusted by the speed of the driven rollers.

[0009] In this specification and below, laminating unit is understood to mean the device that coats substrate with thermoplastic film, especially by pressure.For this purpose, if substrate is designed as film, two film guide rollers are typically provided.If substrate is not designed as film, laminating unit often comprises at least one roller for applying thermoplastic film to substrate.

[0010] The device has the advantage that the thermoplastic film can be guided substantially without contact by controllable driven rollers. Thus, in the feeding device, the film is not at least partially laid flat on a conveyor belt, a large-diameter roller, or another surface, but is merely supported and conveyed at specific points by the controllable driven rollers, possibly deflected, and otherwise guided in a contactless manner. The rotation speed of the driven rollers is controllable, and can even be adjusted, so that tension within the film can be equalized by establishing a speed difference between individual rollers. For example, if the guided film loses tension, the speed difference between two rollers can be set so that the film is again tensioned. This is particularly advantageous, since heating a thermoplastic film both expands and softens it.

[0011] The apparatus for laminating a substrate with a thermoplastic film can also include a substrate supply device, the design of which depends on the type of substrate. In particular, an infrared emitter can be provided as a device for heating the film, but other heat sources, such as a laser, can also be provided. For cooling, a cooled metal sheet, for example, can also be provided.

[0012] According to one embodiment, the driven rollers are arranged at least upstream and downstream of the cooling and heating device in the direction of film movement. This embodiment has the advantage that changes in the length of the thermoplastic film caused by heating or cooling of the film can be compensated for by adjusting the speed of the rollers.

[0013] The thermoplastic film is in particular guided away from the heating device, so that it does not come into contact with elements of the heating device.

[0014] The cooling device may comprise at least one cooling roller along which the film is guided. In this embodiment, a controllable driven roller may be provided, in particular upstream of the cooling roller, by means of which the tension of the film can be controlled or adjusted via the speed difference to the cooling roller.

[0015] Alternatively, the thermoplastic film can be guided away from the cooling device, which in this latter case is positioned along the film web stretched between the rollers of the feeding device, but on the opposite side of the film from the heating device, rather than on the same side.

[0016] According to one embodiment, a grid is arranged between the heating device and the thermoplastic film to protect the heating device from contact with the film. Such a grid has the advantage of preventing contact between the thermoplastic film and the heating device. As an additional safety feature, the feeding device can include at least one device for generating an air flow between the thermoplastic film and the heating device.

[0017] The device for generating the air flow can be designed as a blower, compressed air source, or vacuum source. This has the advantage of preventing the film from adhering to the grid or heating device if the web tension is too low or if the web tears. To this end, the device for generating the air flow can be switched on automatically and / or manually when the web tension is lost. In this case, the device can, for example, blow cool air between the heating device and the film or grid. If a grid is provided, the air passes through the grid and blows the film away from the heating device.

[0018] There are various options for the arrangement of the driven rollers and, optionally, further rollers or deflecting rollers of the feeding device. For example, the thermoplastic film can be guided at least partially vertically upward and / or downward in the feeding device. However, it can also be guided at least partially obliquely upward and / or downward. Furthermore, the thermoplastic film can be guided at least partially on an arc. The choice of arrangement can depend, among other things, on the available space and other practical considerations.

[0019] According to one embodiment, the supply device includes an alternative film supply path that does not include a heating or cooling device. Thus, in this alternative supply path, the film is supplied to the laminating unit without being heated. For example, this alternative supply path can be used if a different material is used for lamination instead of a thermoplastic film, or if the bond between the film and the substrate is established by a different method, such as a separately applied adhesive. The presence of the alternative supply path is particularly advantageous when different methods are used simultaneously or alternately in one system.

[0020] According to one embodiment, the device comprises a device for collecting condensate formed in the cooling device. This device can be designed, for example, as a trough and can be arranged to collect the condensate that forms and drips from the cooling device due to the humid ambient air. That is to say, it is known that considerable amounts of condensate are formed during the operation of the cooling device, and it is not intended that this amount enters the system in a disorderly manner, since this could damage, inter alia, the surface of the thermoplastic film.

[0021] According to a further aspect of the present invention, a method for laminating a substrate with a thermoplastic film is identified, the method comprising feeding the film to a lamination unit, the feeding being effected by a number of controllable driven rollers along which the film is guided, the film being heated on a first side and cooled on a second side during feeding, and the tension of the film during feeding being controlled, and in particular also regulated by the speed of the driven rollers.

[0022] In particular, the speed in the feeder can be partially adjusted, which is made possible by the fact that the driven rollers can be adjusted individually. If the speed of the rollers can be adjusted independently of each other, it is possible to set a speed difference between successive rollers, thereby increasing or decreasing the tension in the film.

[0023] In this way, the film can be guided at least partially contactlessly and supported only at certain points by controllable driven or simple rollers, which also has the advantage that the film experiences lower friction forces than when guided via conveyor belts or rollers.

[0024] A substrate, which may be in the form of a film or in another form, is also fed to the lamination unit.

[0025] According to one embodiment, the film is held away from the heating device by a current of air blown into the space between the film and the heating device, and for this purpose in particular the air blown into the space can exit through openings in the grid to move the film away from the heating device.

[0026] According to one embodiment, the condensate formed on the cooling device is absorbed and optionally drained.

[0027] Embodiments of the invention are explained in more detail below with reference to schematic drawings. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 shows a schematic diagram of an apparatus for laminating a substrate with a thermoplastic film according to a first embodiment of the invention. [Figure 2] FIG. 2 shows a schematic representation of an apparatus for laminating a substrate with a thermoplastic film according to a second embodiment of the invention. [Figure 3] FIG. 3 shows schematically an apparatus for laminating a substrate with a thermoplastic film according to a third embodiment of the invention. [Figure 4] FIG. 4 shows schematically an apparatus for laminating a substrate with a thermoplastic film according to a fourth embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Figure 1 shows an apparatus 1 for laminating a substrate with a thermoplastic film, in which the thermoplastic film is designated by reference numeral 11, the substrate by reference numeral 12 and the already laminated substrate by reference numeral 13.

[0030] The apparatus 1 comprises a laminating unit 2 which comprises, inter alia, a number of rollers 3 for pressing a film 11 onto a substrate 12. Furthermore, the apparatus 1 comprises a feeding device 4 for the laminating unit 2 of the thermoplastic film 11. The film 11 is unwound from an unwinder 5 and conveyed to the laminating unit 2 by the feeding device 4, after which the coated substrate 13 is wound up by a winder 6.

[0031] The feeder 4 comprises a number of controllable driven rollers 10. In the illustrated embodiment, three driven rollers 10 are shown, however this is merely an example and more or fewer driven rollers may be provided.

[0032] The feeding device 4 comprises further rollers or rolls which serve to guide and deflect the film 11, which are shown by way of example only and will not be described in more detail. The thermoplastic film 11 is conveyed to the laminating unit 2 in the direction of arrow 7 by a driven roller 10. In the embodiment shown, the substrate 12 is also conveyed to the laminating unit 2 along arrow 8 by a suitable feeding device 9. After lamination, the laminated substrate 13 is conveyed along arrow 7 to the winder 6.

[0033] The film 11 is fed in a largely contactless manner. Only in the area of ​​the rollers 10 is the film 11 guided or supported at certain points. The film 11 is not supported between the rollers 10. The film is therefore subject to tensions caused, inter alia, by gravity acting on the film and by the rotational speed of the rollers 10.

[0034] Along its path through the feeder 4, the thermoplastic film 11 is guided between rollers 10, past a heating device 14 on a first side 16 of the film 11 and a cooling device 15 on a second side 17 of the film 11. The heating devices 14 and cooling devices 15 are also shown here by way of example only. The number and arrangement of the heating devices 14 and cooling devices 15 can vary.

[0035] Heating the first side 16 softens and partially melts the thermoplastic film 11 on the first side 16 so that it can bond to the substrate 12 in the laminating unit 2. Cooling the second side 17 prevents the film 11 from completely melting and helps maintain a certain stability necessary for the transfer process to the laminating unit 2.

[0036] The film 11 is guided away from the heating device 14 and the cooling device 15. Between the heating device 14 and the film 11 is placed a grid 18 intended to prevent the film 11 from adhering to the heating device 14.

[0037] Feeder 4 includes an alternative feed path for film to laminating unit 2, indicated by dashed line 19 in Figure 1, that is not guided through heating device 14 and cooling device 15. The alternative feed path can be used for films that are not composed of thermoplastic material or that are not heated or cooled for other reasons.

[0038] The apparatus 1 further comprises a trough 20 for collecting condensate that forms on the cooling device 15 due to the humid ambient air. The trough 20 is arranged below the cooling device 15 so that the condensate flows out of the cooling device 15 by gravity and drips into the trough 20. On this path, the condensate does not pass through further elements of the supply device 4, in particular the heating device 14, which may be damaged by the condensate. The trough 20 is thus arranged so that condensate that forms on the apparatus 15 drips directly into the trough 20. Draining the condensate ensures that there is no contact between the condensate and the film 11, which could deteriorate the quality of the surface.

[0039] Figure 2 shows a second embodiment of an apparatus 1 for laminating a substrate with a thermoplastic film. This apparatus 1 differs from the embodiment shown in Figure 1 in that it is provided with several driven rollers 10 that guide the film 11 on a semicircular path.

[0040] 3 shows a third embodiment of an apparatus 1 for laminating a substrate with a thermoplastic film 11. This embodiment differs from the previous ones in that several driven rollers 10 are arranged one above the other so that the film 11 is guided partially vertically. In the embodiment shown, two heating devices 14 and two cooling devices 15 are arranged one above the other.

[0041] This configuration is particularly space-saving and can be implemented in a small installation space. In this embodiment, the cooling devices 15 are arranged one above the other, but not above the heating device 14, so that condensate does not drip onto the heating device 14. A trough 20 for collecting condensate is again provided immediately below the lower cooling device 15.

[0042] 4 shows a fourth embodiment of an apparatus 1 for laminating a substrate 12 with a thermoplastic film 11. This embodiment differs from the previous ones in that the film 11 is not guided in a contactless manner in the feeding device 4, but is instead partially guided by a cooling roller 21. The second side 17 of the film 11 is therefore placed in a predetermined position on the surface of the cooling roller 21. The speed of the cooling roller 21 can also be controlled and driven.

[0043] However, the film is guided contactlessly in the route between the first driven roller 10 and the cooling roller 21. Said roller 10 has the task of compensating for the stresses induced in the film 11 by heating.

[0044] In this embodiment, a scraper 22 is provided which scrapes the condensate formed on the cooling roller 21 from the roller 21 and causes it to drip into the trough 20. In this case, the scraper 22 is arranged in the region of the lower surface 23 of the roller 21, while the film 11 is guided on the upper surface 24 of the roller 21. In this way, contact between the condensate on the surface of the roller 21 and the film 11, which could deteriorate the quality of the film 11, is prevented. Preferred aspects of the present invention include the following. [1] An apparatus (1) for laminating a substrate (12) with a thermoplastic film (11), said apparatus (1) comprising: a laminating unit (2) for laminating the substrate (12) with a thermoplastic film (11); A feeding device (4) for feeding the thermoplastic film (11) to the laminating unit (2). Equipped with wherein the feeding device (4) for the thermoplastic film (11) comprises a device (14) for heating a first side (16) of the film (11) and a device (15) for cooling a second side (17) of the film (11), as well as a number of controllable driven rollers (10) by which the film (11) is guided to pass through the heating device (14) and the cooling device (15), and the tension of the film (11) can be adjusted by the speed of the driven rollers (10). [2] The device (1) according to [1], wherein the driven roller (10) is arranged upstream and downstream of at least the heating and cooling devices (14, 15) in the moving direction of the film (11). [3] The apparatus (1) according to [1], wherein the thermoplastic film (11) is guided away from the heating device (14). [4] The apparatus (1) according to any one of [1] to [3], wherein the cooling device (15) includes at least one cooled roller (21) along which the film (11) is guided. [5] The device (1) according to any one of [1] to [3], wherein the thermoplastic film (11) is guided away from the cooling device (15). [6] The device (1) according to any one of [1] to [5], wherein a grid (18) is disposed between the heating device (14) and the thermoplastic film (11) to prevent the heating device (14) from coming into contact with the film (11). [7] The apparatus (1) according to any one of [1] to [6], wherein the supply device (4) comprises at least one device for generating an air flow between the thermoplastic film (11) and the heating device (14). [8] The device (1) according to any one of [1] to [7], wherein the thermoplastic film (11) is guided at least partially vertically upward and / or downward within the feeding device (4). [9] The device (1) according to any one of [1] to [8], wherein the thermoplastic film is guided at least partially obliquely upward and / or downward within the feeding device.

[10] The device (1) according to any one of [1] to [9], wherein the thermoplastic film (11) is guided at least partially on an arc within the supply device (4).

[11] The apparatus (1) according to any one of [1] to

[10] , wherein the supply device (4) is provided with an alternative supply path for the film (11) that does not include any heating device (14) or cooling device (15).

[12] The apparatus (1) according to any one of [1] to

[11] , further comprising a device (20) for collecting condensate produced in the cooling device (15).

[13] A method for laminating a substrate (12) with a thermoplastic film (11), said method comprising feeding said film (11) to a laminating device (2), said feeding being performed by a number of controllable driven rollers (10) along which said film (11) is guided, said film (11) being heated on a first side (16) and cooled on a second side (17) during feeding, and wherein tension in said film (11) during feeding is adjusted by the speed of said driven rollers (10).

[14] The method according to

[13] , wherein the film (11) is held away from the heating device (14) by an air flow blown into a space between the film (11) and the heating device (14).

[15] The method according to

[13] or

[14] , wherein the condensate formed in the cooling device (15) is collected. [Explanation of symbols]

[0045] 1 device 2 Laminating Unit 3 Rollers 4 Feeding device 5 Unwinding machine 6 Winder 7 Arrows 8 Arrows 9 Feeding device 10 Roller 11 Film 12 Base material 13 Laminated substrate 14 Heating device 15 Cooling device 16 First Side 17 Second Side 18 Grid 19 Dashed Line 20 Trough 21 Roller 22 Scraper 23 Bottom side 24 Top side

Claims

1. An apparatus (1) for laminating a substrate (12) with a thermoplastic film (11), said apparatus (1) comprising: a laminating unit (2) for laminating the substrate (12) with a thermoplastic film (11); a feeding device (4) for feeding the thermoplastic film (11) to the laminating unit (2); Equipped with wherein the supply device (4) for the thermoplastic film (11) comprises a device (14) for heating a first side (16) of the thermoplastic film (11) and a device (15) for cooling a second side (17) of the thermoplastic film (11), and a number of controllable driven rollers (10) by which the thermoplastic film (11) is guided to pass through the heating device (14) and the cooling device (15), and the tension of the thermoplastic film (11) can be adjusted by the speed of the driven rollers (10); The apparatus further comprises a grid (18) disposed between the heating device (14) and the thermoplastic film (11) to prevent the heating device (14) from contacting the thermoplastic film (11).

2. 2. The device (1) according to claim 1, wherein the driven roller (10) is arranged upstream and downstream of at least heating and cooling devices (14, 15) in the direction of movement of the thermoplastic film (11).

3. 3. The device (1) according to claim 1 or 2, wherein the thermoplastic film (11) is guided away from the heating device (14).

4. Apparatus (1) according to any of the preceding claims, wherein the cooling device (15) comprises at least one cooled roller (21) along which the thermoplastic film (11) is guided.

5. The device (1) according to any one of claims 1 to 3, wherein the thermoplastic film (11) is guided away from the cooling device (15).

6. The device (1) according to any one of claims 1 to 5, wherein the supply device (4) comprises at least one device for generating an air flow between the thermoplastic film (11) and the heating device (14).

7. The device (1) according to any of the preceding claims, wherein the thermoplastic film (11) is guided at least partly vertically upwards and / or downwards in the feeding device (4).

8. Apparatus (1) according to any of the preceding claims, wherein the thermoplastic film is guided at least partly obliquely upwards and / or downwards in the feeding device.

9. The device (1) according to any one of the preceding claims, wherein the thermoplastic film (11) is guided in the feeding device (4) at least partially on a circular arc.

10. The apparatus (1) according to any of the preceding claims, wherein the feeding device (4) comprises an alternative feeding path for the film (11) that does not include any heating device (14) or cooling device (15).

11. The apparatus (1) according to any one of the preceding claims, further comprising a device (20) for collecting condensate produced in the cooling device (15).

12. A method for laminating a substrate (12) with a thermoplastic film (11), said method comprising feeding said thermoplastic film (11) to a laminating device (2), said feeding being performed by a number of controllable driven rollers (10) along which said thermoplastic film (11) is guided, said thermoplastic film (11) being heated on a first side (16) and cooled on a second side (17) during feeding, and the tension of said thermoplastic film (11) being adjusted by the speed of said driven rollers (10), A method wherein the thermoplastic film (11) is held away from the heating device (14) by a current of air blown into the space between the thermoplastic film (11) and the heating device (14).

13. 13. The method according to claim 12, wherein the condensate formed in the cooling device (15) is collected.

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