USING A SELF-ADHESIVE PLASTIC FILM

Description

[0001] The invention relates to a use of a self-adhesive plastic film.

[0002] The use of self-adhesive plastic films—that is, plastic films coated with adhesive on one side—is known in the art in various forms and for various applications. In addition to their use as labeling films, which are printed and / or cut to any desired shape, the full or partial bonding of, for example, vehicles or vehicle parts is also known as an alternative to repainting and / or as surface protection. Microstructured films are also known, with which the surface properties of a bonded surface can be modified. Thus, suitable microstructures can achieve self-cleaning effects or a reduction in frictional resistance on surfaces subject to turbulent flow.

[0003] When self-adhesive plastic films are applied to surfaces exposed to high airflow, such as the outer skin of aircraft, increased erosion of the film regularly occurs at the edge of the film facing the airflow due to high flow velocities and / or particles entrained by the flowing fluid. As a result, partially eroded plastic films must be regularly removed and replaced with new plastic films. This is particularly labor-intensive and costly, especially for large-area plastic films.

[0004] Documents EP 1 557 440 A1 and EP 2 631 278 A1 describe adhesive tapes whose longitudinal edges are provided with a serrated shape in order to improve the tool-free, manual tearing off of a piece of adhesive tape to a desired length.

[0005] The document US 2004 / 0126541 A concerns a riblet film with a correspondingly designed surface.

[0006] The document US 2015 / 0225069 A1 describes an adhesive patch for airflow control to reduce noise in aircraft.

[0007] Also well known are patterned foils for decorating cars and painter's tape for decorating interior walls.

[0008] The invention is based on the object of using a plastic film in such a way that the disadvantages of the prior art no longer occur or only occur to a reduced extent.

[0009] This object is achieved by using a plastic film according to claim 1. Advantageous further developments are the subject of the dependent claims.

[0010] A self-adhesive plastic film is apparently provided for application to surfaces over which water flows, wherein the plastic film is flat, has a circumferential edge and is provided with adhesive on one side, and the edge of the plastic film is designed at least in sections as a wavy edge in the plane of the film.

[0011] Furthermore, a surface over which a flow passes is disclosed, with a self-adhesive plastic film applied thereto, wherein there is at least one predetermined main flow direction for the flow over the surface, the plastic film is designed according to the disclosure of the description and the plastic film is arranged on the surface over which a flow passes in at least one main flow direction onto a wavy edge of the plastic film.

[0012] The invention relates to the use of a self-adhesive art

[0013] plastic film on a surface over which a flow occurs with at least one predetermined main flow direction, wherein the plastic film is flat, has a circumferential edge, is provided with adhesive on one side and is glued to the surface over which a flow occurs in such a way that the flow over the surface in at least one main flow direction impinges on a wavy edge of the plastic film, and wherein in order to reduce the erosion of the plastic film, the edge of the plastic film is designed at least in sections as a wavy edge in the plane of the film, wherein the wave shape has an amplitude of 1 cm to 10 cm and a wavelength of 1 cm to 10 cm.

[0014] First, some terms used in connection with the invention will be explained.

[0015] A "flowing surface" is a surface over which a fluid—for example, air—flows in such a way that wall friction occurs between the fluid and the surface. The flow can be laminar or turbulent.

[0016] A "main flow direction" refers to the direction in which the airflow over a surface predominantly occurs or is expected. In an aircraft, the main flow direction over the outer wall—which can vary locally across the entire outer wall—results, for example, from the airflow around the aircraft during cruise flight. On the outer wall of an express train, for example, two main flow directions can be expected, which are decisive depending on the direction of travel of the train.

[0017] The invention recognizes that erosion of plastic films applied to surfaces subject to flow occurs particularly at the edge directly impacted by the flow. At this edge, the plastic film acts as a step on the surface being flowed over and thus represents a flow obstacle. The plastic film is already subjected to greater stress by the flow itself at the edge in question than in the rest of the area. Furthermore, particles carried along by the flow fluid—such as grains of sand or ice crystals—regularly impact the step at the edge in question of the plastic film. Erosion of the plastic film at this edge is therefore significantly greater than in the rest of the plastic film.

[0018] When using the plastic film according to the invention, this erosion is reduced by partially forming the edge of the plastic film as a wavy edge in the plane of the film. The wavy shape of the edge is therefore visible in the plan view of the film. If the section of the edge onto which the flow impinges has a corresponding wavy edge, erosion in this area can be significantly reduced. The wavy shape of the edge changes the flow in the area of the correspondingly designed edge in such a way that the effects that promote erosion, e.g., the impact of particles carried by the flow, can be reduced.

[0019] The wave-shaped edge can preferably be sawtooth-shaped, triangular, or sinusoidal. The waveform has an amplitude of 1 cm to 10 cm, preferably an amplitude of 1 cm to 5 cm, more preferably approximately 2 cm. The lateral extension of a wave of the waveform, comparable to the wavelength, is 1 cm to 10 cm, more preferably 1 cm to 5 cm, and particularly preferably approximately 2 cm.

[0020] In many cases, the plastic film has a substantially rectangular shape. In this case, it is preferred if at least one side of the rectangle is designed as a wavy edge. The plastic film can then be applied to a surface with this side oriented against the main flow direction. Particularly in cases where there are multiple main flow directions, however, several sides of the plastic film can also be designed as wavy edges.

[0021] It is preferred if the plastic film is beveled, at least in the region of the wavy edge, such that the side coated with adhesive protrudes beyond the other side. In cross-section, the plastic film thus has a wedge shape at the wavy edge, which, when applied to a surface, can further improve the flow in the region of the edge in question. The additional wedge shape can further reduce the flow effects that cause or at least promote erosion.

[0022] The plastic film can be a sacrificial film, lacquer film, image film, or riblet film. A lacquer film is usually a single-colored plastic film whose surface is at least similar to lacquer in appearance and / or technical properties. An image film can be provided with any pattern, for example, using digital printing.

[0023] A sacrificial film is a plastic film that is used to protect another, usually larger and / or higher-quality film. The areas of the other film's edge where erosion is expected are overlapped. The erosion then occurs on the cheaper and / or easier-to-replace sacrificial film, but not on the film being protected.

[0024] A riblet film is a microstructured film whose structure reduces the frictional resistance during a turbulent overflow in at least one predetermined direction, which preferably coincides with the at least one main flow direction.

[0025] The plastic film can preferably be made of polyvinyl chloride (PCV), polyurethane (PU), polyethylene (PE) or polyethylene terephthalate (PET), the adhesive can be an acrylic-based adhesive.

[0026] In the case of the overflow surface with a self-adhesive plastic film applied thereto, where the overflow over the surface has at least one predetermined main flow direction, the plastic film is arranged on the overflow surface in such a way that the overflow over the surface impinges on a wavy edge of the plastic film in at least one main flow direction. For further explanation, reference is made to the above explanations.

[0027] The plastic film can, in particular, be a sacrificial film, which is arranged overlapping at least in the areas above the edge of a film to be protected, and which is impinged upon by the flow in at least one main flow direction. In this case, any erosion occurs on the sacrificial film, but not on the film protected by the sacrificial film. To minimize erosion of the sacrificial film, it is designed according to the disclosure of the description, thus, in particular, having a wavy edge arranged according to the main flow direction(s).

[0028] If the plastic film is a sacrificial film, the overlap with the film to be protected is preferably 1.5 cm to 5 cm, preferably 1.5 cm to 2.5 cm, and more preferably approximately 2 cm. The overlap is defined as the length, starting from the edge of the film to be protected, over which the sacrificial film is adhered to the film to be protected. Such an overlap provides both good erosion protection and minimal additional weight due to the sacrificial film.

[0029] If the plastic film is to replace an already damaged or eroded sacrificial film, the latter can first be removed before the new plastic film is applied. However, it is also possible to apply the plastic film directly over a damaged or eroded sacrificial film. In this case, the damaged or eroded sacrificial film remains underneath the newly applied plastic film.

[0030] The surface over which the air flows may preferably be the outer skin of an aircraft, preferably a commercial aircraft.

[0031] For an explanation of the use according to the invention, reference is made to the above statements.

[0032] The invention will now be described by way of example using advantageous embodiments with reference to the accompanying drawings. They show: Figure 1a, b: a first embodiment of a surface over which a flow passes with a plastic film; Figure 2a, b: a second embodiment of a surface over which a flow passes with a plastic film; Figure 3a, b: a third embodiment of a surface over which a flow passes with a plastic film; and Figure 4: an alternative embodiment for protecting films from erosion by means of a sacrificial film.

[0033] In <h2 style=";text-align:left;direction:ltr">Figure 1a, ba first embodiment of a flow-over surface 1 with a plastic film 10 is shown both in a top view and in a side view.

[0034] The overflow surface 1 is a section of the outer skin of an aircraft (not shown) over which air flows during cruise flight in the main flow direction indicated by the arrow 90.

[0035] A flat, self-adhesive plastic film 10 is arranged on the surface 1. The plastic film 10 is firmly bonded to the surface 1 by means of its adhesive coating on the side 12 facing the surface 1 and has a rectangular shape.

[0036] On the side of the rectangular plastic film 10 on which the air flow impinges on the plastic film 10 in the main flow direction 90, the edge of the plastic film 10 is formed as a wavy edge 11. The wavy edge 11 is triangular in shape.

[0037] In addition, the plastic film 10 is bevelled in the region of the wavy edge 11 such that the side 12 of the plastic film 10 provided with adhesive protrudes beyond the other side 13.

[0038] The correspondingly designed edge 11 can reduce the erosion of the plastic film 10 as a result of the overflow.

[0039] In <h2 style=";text-align:left;direction:ltr"> Figure 2a, b A second embodiment of a surface 1 is shown, over which the fluid flows in the main flow direction 90. The plastic film 10 in this embodiment is comparable to that of <h2 style=";text-align:left;direction:ltr"> Figure 1a, bdesigned, whereby the plastic film 10 is used as a sacrificial film 10 for the film 20 to be protected.

[0040] The essentially rectangular plastic film 10 is adapted to overlap the surface 1 or the film 20 to be protected with the edge facing the flow direction 90. The overlap 21 is approximately 2 cm. The film 20 is largely protected by the plastic film 10 from erosion due to the flow direction 90.

[0041] In order to keep the erosion of the plastic film 10 as low as possible despite its property as a sacrificial film itself, the plastic film 10 has a wavy edge 11 on its edge facing the flow.

[0042] In the embodiment according to <h2 style=";text-align:left;direction:ltr"> Figure 2a, bthe wave-shaped edge 11 is triangular. Alternatively, the wave-shaped edge 11 can also be sinusoidal, for example. The same applies to the embodiment in <h2 style=";text-align:left;direction:ltr"> Figure 3a, b shown, which otherwise corresponds to the embodiment according to <h2 style=";text-align:left;direction:ltr"> Figure 2a, b matches.

[0043] The <h2 style=";text-align:left;direction:ltr"> Figure 2a, b and <h2 style=";text-align:left;direction:ltr"> 3a, bThe plastic films 10 shown, i.e., sacrificial films used, already have a reduced tendency to erosion due to their wavy edge 11. Nevertheless, even a corresponding sacrificial film represents a flow obstacle for the flow 90 along the surface 1, so that erosion generally occurs at the wavy edge 11, albeit to a significantly reduced extent compared to films from the prior art. Particularly in aircraft construction, however, it is even possible in some scenarios to apply a sacrificial film to a surface in such a way that it does not form a direct flow obstacle due to the transition from surface to sacrificial film, whereby the erosion-promoting effects occurring due to a flow obstacle can also be avoided.

[0044] In <h2 style=";text-align:left;direction:ltr"> Figure 4is shown as an example how a wing profile 50 is covered with a foil 53, 54 on both the upper side 51 and the lower side 52. The sacrificial foil 55 extends completely over the profile nose 56 in such a way that it overlaps with both foils 53, 54. <h2 style=";text-align:left;direction:ltr"> Figure 4 The arrangement of the sacrificial foil shown may require independent protection.

Claims

1. Use of a self-adhesive plastic film (10) on an overflowed surface (1), with at least one predetermined main direction of flow (90), wherein the plastic film (10) is planar, has a peripheral border, is provided with adhesive on one side (12) and is adhesively attached on the overflowed surface (1) in such a way that the overflow of the surface (1) in at least one predetermined main direction of flow (90) impinges on a wavy edge (11) of the plastic film (10), characterized in that, to reduce the erosion of the plastic film (10), the border of the plastic film (10) is designed at least in some portions as an edge (11) that is wavy in the plane of the film, wherein the wave form has an amplitude of 1 cm to 10 cm and a wave length of 1 cm to 10 cm.

2. Use according to Claim 1, characterized in that the plastic film (10) is a sacrificial film, which is arranged as overlapping at least in the regions over the border of a film (20) to be protected that are impinged by the flow in at least one main direction of flow (90).

3. Use according to one of the preceding claims, characterized in that the overlap (21) is 1.5 cm to 5 cm, preferably 1.5 cm to 2.5 cm, more preferably about 2 cm.

4. Use according to one of the preceding claims, characterized in that the plastic film (10) is adhesively attached as a sacrificial film over an already worn sacrificial film.

5. Use according to one of the preceding claims, characterized in that the overflowed surface (1) is the outer skin of an aircraft.

6. Use according to one of the preceding claims, characterized in that the wavy edge (11) is of a sawtooth, triangular or sinusoidal form, wherein the wave form preferably has an amplitude of 1 cm to 5 cm, more preferably of approximately 2 cm, and / or the wave form has a wave length of preferably 1 cm to 5 cm, particularly preferably approximately 2 cm.

7. Use according to one of the preceding claims, characterized in that the plastic film (10) has a rectangular form and at least one side of the rectangle is designed as a wavy edge (11).

8. Use according to one of the preceding claims, characterized in that, at least in the region of the wavy edge (11), the plastic film (10) is bevelled in such a way that the side (12) of the plastic film that is provided with adhesive is projecting beyond the other side (13).

9. Use according to one of the preceding claims, characterized in that the plastic film (10) is designed as a sacrificial film, lacquer film, image film or riblet film.

10. Use according to one of the preceding claims, characterized in that the plastic film (10) is of polyvinyl chloride (PCV), polyurethane (PU), polyethylene (PE) or polyethylene terephthalate (PET) and / or the adhesive is an acrylic-based adhesive.