JP2023145307A - Fluid resistance reduction film, roll body and method for manufacturing fluid resistance reduction film - Google Patents

Abstract

To provide a fluid resistance reduction film capable of being applied to a surface of an object to effectively reduce fluid resistance, a roll body, and a method for manufacturing a fluid resistance reduction film.SOLUTION: A fluid resistance reduction film of the present disclosure is a fluid resistance reduction film having a fluid resistance reduction structure capable of reducing fluid resistance, and has, on a first surface, first regions having an uneven structure composed of convex parts and concave parts and second regions adjacent to the first region. The first regions and the second regions are alternately arranged in a first direction on the first surface. The first regions and the second regions extend in a band shape in a direction intersecting the first direction. The extent of elongation in the first direction on the first surface is smaller than the extent of elongation in the direction in which the first regions and the second regions extend in a band shape.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a fluid resistance reduction film, a roll body, and a method for manufacturing a fluid resistance reduction film.

BACKGROUND ART In recent years, research on fluid resistance reduction technology has been actively conducted in the fields of moving objects that move in fluids, fluid transfer, etc., in order to save energy and reduce carbon dioxide emissions.

BACKGROUND ART Conventionally, as a fluid resistance reduction technique, for example, providing unevenness on the surface of an object is known. For example, Patent Document 1 describes a technical concept that generates longitudinal vortices at the boundary between a smooth wall surface and a rough surface where minute irregularities are uniformly distributed to suppress separation of flow from the wall surface. Disclosed. Further, Patent Document 1 discloses a method of attaching a tape or sheet having unevenness to the surface as a method of providing a rough surface.

Japanese Patent Application Publication No. 2013-57390

The above-mentioned Patent Document 1 does not mention in detail the relationship between the elongation of a film having an uneven structure on its surface as a fluid resistance reducing structure and the unevenness. Further, there is no specific disclosure regarding means for applying a fluid resistance reduction structure to the surface of an object.
Here, when a film having a fluid resistance reduction structure is applied to the surface of an object, a curved surface having a small radius of curvature in a specific direction, such as a corner between two surfaces of the object, is applied to the surface of an object. may be applied to continuous surfaces including For example, a film may be applied from the front of a truck, bus, train, etc. to the side through the corner. When pasting, the film may be stretched from the front surface toward the side surface through the corner portion in order to follow the curved surface such as the corner portion. Therefore, it is preferable that the film has a certain degree of elongation in at least one direction from the viewpoint of facilitating attachment.
However, when a film having an uneven structure as a fluid resistance reducing structure is stretched, depending on the shape and material of the uneven structure, the film may not be able to withstand the stretching and may suffer damage such as collapse or peeling. If the uneven structure is damaged, the effect of effectively reducing fluid resistance may be hindered.

The present disclosure has been made in view of the above circumstances, and when applied to the surface of an object, it is applied to a surface including a curved surface having a small radius of curvature in a specific direction, such as a corner. The main object of the present invention is to provide a fluid resistance reducing film, a roll body, and a method for producing a fluid resistance reducing film that can effectively reduce fluid resistance even when the fluid resistance is reduced.

The fluid resistance reduction film of the present disclosure is a fluid resistance reduction film having a fluid resistance reduction structure capable of reducing fluid resistance, and includes a first region having a concavo-convex structure composed of convex portions and concave portions on a first surface. a second region adjacent to the first region; the first region and the second region are alternately arranged in a first direction on the first surface; The two regions extend in a strip shape in a direction intersecting the first direction, and the magnitude of the elongation in the first direction on the first surface is equal to the elongation in the direction in which the first region and the second region extend in the strip shape. smaller than the size of

In the fluid resistance reducing film of the present disclosure, a plurality of the convex portions may be arranged in the direction in which the first region extends.

In the fluid resistance reducing film of the present disclosure, a distance between adjacent convex portions in the direction in which the first region extends may be 1 to 12 times the height of the convex portions.

In the fluid resistance reducing film of the present disclosure, the convex portion may have a shape extending linearly along the first direction.

In the fluid resistance reducing film of the present disclosure, the width of the convex portion in a direction perpendicular to the first direction that extends linearly along the first direction is 1 times or more the height of the convex portion or more. It may be twice or less.

In the fluid resistance reducing film of the present disclosure, the length of the convex portion extending linearly along the first direction may be 0.2 mm or more and 50 mm or less.

In the roll body of the present disclosure, the fluid resistance reducing film is wound in the first direction.

The method for manufacturing a fluid resistance reduction film of the present disclosure includes a base material preparation step of preparing a resin base material constituting the fluid resistance reduction film, and a step of preparing a resin base material that intersects in the first direction on the first surface of the resin base material. a step of forming a fluid resistance reduction structure in which the first region and the second region extending in a direction are alternately formed in the first direction; and the fluid resistance reduction structure forming step in which the first region and the second region are formed. A winding step of winding up the resistance reducing film in the first direction.

The method for manufacturing a fluid resistance reduction film of the present disclosure includes a base material preparation step of preparing a resin base material constituting the fluid resistance reduction film, and a step of preparing a resin base material that intersects in the first direction on the first surface of the resin base material. a step of forming a fluid resistance reduction structure in which the first region and the second region extending in a direction are alternately formed in the first direction; and the fluid resistance reduction structure forming step in which the first region and the second region are formed. a winding step of winding up the resistance reducing film in the first direction, and the fluid resistance reducing structure forming step includes winding the resistance reducing film in the first region using a cylindrical plate that rotates along the first direction. , the method may include the step of forming a protrusion extending linearly along the first direction.

According to the present disclosure, it is possible to provide a fluid resistance reduction film that can be applied to the surface of an object to effectively reduce fluid resistance.

A schematic plan view and a schematic cross-sectional view showing an example of the fluid resistance reduction film of the present disclosure A schematic perspective view showing an example of the fluid resistance reduction film of the present disclosure Schematic diagram illustrating gas flow in the fluid resistance reduction film of the present disclosure Schematic diagram explaining gas flow in fluid resistance reduction film Schematic cross-sectional view illustrating the fluid resistance reduction film of the present disclosure A schematic perspective view showing another example of the fluid resistance reduction film of the present disclosure A schematic plan view and a schematic cross-sectional view showing other examples of the fluid resistance reduction film of the present disclosure A schematic plan view and a schematic cross-sectional view showing other examples of the fluid resistance reduction film of the present disclosure Diagram showing an application example of the fluid resistance reduction film of the present disclosure A schematic cross-sectional view illustrating the laminated structure of the fluid resistance reduction film of the present disclosure A diagram showing an example of a roll body of the present disclosure Schematic diagram explaining an example of another roll body Schematic diagram illustrating an example of the method for manufacturing the fluid resistance reduction film of the present disclosure Schematic diagram illustrating an example of another method for producing a fluid resistance reduction film

Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different ways, and should not be construed as being limited to the description of the embodiments exemplified below. Further, in order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual form, but this is just an example and does not limit the interpretation of the present disclosure. It's not something you do. In addition, in this specification and each figure, the same elements as those described above with respect to the previously shown figures are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

In this specification, when expressing a mode in which another member is placed on top of a certain member, when it is simply expressed as “above” or “below”, unless otherwise specified, the term This includes both cases in which another member is placed directly above or below a certain member, and cases in which another member is placed above or below a certain member via another member. In addition, in this specification, when expressing a mode in which another member is placed on the surface of a certain member, when it is simply written as "on the surface", unless otherwise specified, it means directly above the certain member so as to be in contact with it, Alternatively, it includes both a case where another member is placed directly below a certain member, and a case where another member is placed above or below a certain member via another member.

Moreover, in this specification, the form of a "film" includes a form of a "sheet form", a "web form", and a form of a "roll body".

Hereinafter, the fluid resistance reducing film, roll body, and method for manufacturing the fluid resistance reducing film of the present disclosure will be described in detail.

[Fluid resistance reduction film]
First, the fluid resistance reduction film of the present disclosure will be explained. The fluid resistance reduction film of the present disclosure has a fluid resistance reduction structure capable of reducing fluid resistance on its surface. More specifically, the fluid resistance reducing film of the present disclosure has a first region having an uneven structure and a second region adjacent to the first region on the first surface. The first regions and the second regions are alternately arranged in the first direction on the first surface. Further, the first region and the second region extend in a belt shape in a direction intersecting the first direction. In the fluid resistance reducing film of the present disclosure, the extent of elongation in the first direction on the first surface is smaller than the extent of elongation in the direction in which the first region and the second region extend in a strip shape.

The fluid resistance reduction film of the present disclosure can reduce fluid resistance by applying it to the surface of an object, and as a result, can save energy and reduce carbon dioxide emissions.
Further, the fluid resistance reducing film of the present disclosure can be applied to the surface of an object by, for example, pasting, and a fluid resistance reducing structure can be easily provided to the surface of the object. Further, the fluid resistance reducing film of the present disclosure can be applied to curved surfaces and three-dimensional shapes. Further, the fluid resistance reducing film of the present disclosure can be reapplied or replaced.
Furthermore, the fluid resistance reduction film of the present disclosure has a smaller elongation in a specific direction than an elongation in a direction crossing this specific direction, so it follows the surface of an object and stretches in a direction crossing this specific direction. Even when stretched, it is possible to prevent the concave-convex structure that constitutes the fluid resistance reduction structure from being damaged, and it can be applied to the surface of an object, especially the surface of an object with a curved surface, to effectively reduce fluid resistance. I can do it.
The fluid resistance reducing film of the present disclosure can be preferably applied to the flow of gas, especially air, among fluids.

Hereinafter, each structure of the fluid resistance reduction film of the present disclosure will be explained using the drawings.

1. Fluid resistance reduction structure

FIG. 1 is a schematic plan view and a schematic sectional view showing an example of the fluid resistance reducing film of the present disclosure, and FIG. 1(a) is a schematic plan view showing an example of the fluid resistance reducing film of the present disclosure, and FIG. b) is a sectional view taken along line AA in FIG. 1(a), and FIG. 1(c) is a sectional view taken along line BB in FIG. 1(a). Moreover, FIG. 2 is a schematic perspective view illustrating the fluid resistance reduction film of the present disclosure.
In addition, in FIG. 1, a sheet-like fluid resistance reduction film having a substantially rectangular planar shape is illustrated.

As shown in FIGS. 1(a) to (c) and FIG. 2, the fluid resistance reduction film 1 has a first region 2 on the first surface 10 and a second region 3 adjacent to the first region 2. The first regions 2 and the second regions 3 are arranged alternately in the first direction d1. Further, the first region 2 and the second region 3 extend in a belt shape in a direction intersecting the first direction (direction d2 in FIG. 1).
The first region 2 is provided with a concavo-convex structure 4 having convex portions 11 and concave portions 12, and a plurality of convex portions 11 and concave portions 12 are arranged in the direction in which the first region 2 extends (direction d2 in FIG. 1). ing.

1(a) to (c) and FIG. 2, H1 indicates the height of the convex portion 11, L1 indicates the length of the first region 2 in the direction in which the first region 2 extends (direction d2), and W1 indicates the width of the first region 2 in the first direction d1, and W2 indicates the width of the second region 3 in the first direction d1.

Here, the "height of the convex part 11" is the distance from the bottom to the top of the convex part 11, and in the fluid resistance reduction film 1 shown in FIG. It can also be defined as a step difference between the portion 11 and the recessed portion 12.

Furthermore, the "length of the first region 2" refers to the length of the first region 2 from the end of the convex portion 11 located at one end of the first region 2 in the direction in which the first region 2 extends (direction d2). This is the distance to the end of the convex portion 11 located at the other end of the first region 2 in the extending direction (direction d2).
For example, the length L1 of the first region 2 in the fluid resistance reduction film 1 shown in FIG. It can be defined as the distance to the right end of the convex portion 11 located at the right end of the first region 2 in the direction d2 shown in (a).

Further, the "width of the first region 2" is the distance from one end to the other end in the first direction d1 of the convex parts 11 arranged in the first region 2, and for example, In the resistance reduction film 1, the width W1 of the first region 2 is defined as the distance from one end to the other end in the first direction d1 of the convex portions 11 arranged in the first region 2 shown in FIG. 1(a). can be stipulated.

Moreover, the "width of the second region 3" refers to the distance from the end of the convex portions 11 arranged in one of the first regions 2 adjacent to the second region 3 on the second region 3 side in the first direction d1. , is the distance to the end of the convex portion 11 arranged in the other first region 2 adjacent to the second region 3 on the second region 3 side.
For example, the width W2 of the second region 3 in the fluid resistance reduction film 1 shown in FIG. From the end of the arranged convex parts 11 on the second region 3 side to the second region 3 side of the convex parts 11 arranged in the first region 2 adjacent to the second region 3 and lower in the figure. It can be defined as the distance to the edge.

In addition, each dimension and interval of the above-mentioned convex part 11 can be measured with a laser microscope, a stylus type surface profiler, or a scanning electron microscope (SEM).

3(a) and 3(b) are schematic diagrams illustrating the flow of gas in the fluid resistance reduction film of the present disclosure, and FIG. 3(b) is a cross-sectional view taken along the line AA in FIG. 3(a). . As shown in FIG. 3(a), when the gas F flows along the direction d2 on the surface (first surface 10) of the fluid resistance reduction film 1, as shown in FIG. 3(b), the first region 2 and A vortex is generated near the boundary between the first region 2 and the adjacent second region 3 . This vortex also includes a longitudinal vortex LV having a component in a direction perpendicular to the surface (first surface 10) of the fluid resistance reduction film 1. By generating this longitudinal vortex LV, it is possible to suppress the flow of gas F from peeling off from the surface of the fluid resistance reduction film 1.
That is, by applying the fluid resistance reduction film 1 to the surface of an object by pasting or the like, fluid resistance (particularly pressure resistance) applied to the object can be reduced.

In the fluid resistance reduction film 1, since the length L1 of the first region 2 in the direction in which the first region 2 extends (direction d2) is equal to or greater than a predetermined value, longitudinal vortices LV can be effectively generated. .

Here, when an object is placed in a gas flow, the drag that acts on the object includes, for example, pressure resistance and frictional resistance, and pressure resistance is generally generated by separation of the gas flow. Pressure resistance becomes a problem, for example, in moving objects such as cars, trains, and airplanes, in pipes such as ducts and gas pipes, and in objects such as windmills and air conditioning equipment. The flow velocity is, for example, about 3 m/s or more and 250 m/s or less (about 10 km/h or more and 900 km/h or less).

In the uneven structure, for example, when the flow velocity of the gas flowing through the object is within the above range, the height H1 of the convex portion 11 is appropriately adjusted within a predetermined range to facilitate the generation of longitudinal vortices LV. I can do it.

Here, in the flow around an object, the extremely thin layer on the surface of the object is strongly affected by viscosity. The layer that is strongly affected by this viscosity is called the boundary layer.

FIGS. 4(a) to 4(c) are schematic diagrams illustrating the flow of gas in the fluid resistance reduction film. More specifically, the width W1 of the first region 2 and the width W2 of the second region 3 of the fluid resistance reduction film 1 shown in FIG. FIG. 3 is a schematic diagram showing the relationship between the longitudinal vortex LV generated near the boundary between region 2 and the second region. Note that in FIGS. 4(a) to 4(c), δ indicates the thickness of the above-mentioned boundary layer.

For example, as shown in FIG. 4(a), when the width W1 of the first region 2 and the width W2 of the second region 3 are large, a large longitudinal vortex LV occurs near the boundary between the first region 2 and the second region. Although the vertical vortex LV is generated, it is difficult for the longitudinal vortex LV to wrap around the central portion of the first region 2 and the central portion of the second region.
For example, as shown in FIG. 4(c), when the width W1 of the first region 2 and the width W2 of the second region 3 are small, vertical The vortex LV is small and it is difficult for the longitudinal vortex LV to reach the outer edge of the boundary layer (thickness δ).
That is, if the width W1 of the first region 2 and the width W2 of the second region 3 are inappropriate for the speed of the gas flow, separation of the gas flow can be suppressed, but the effect is small. .

On the other hand, by setting the width W1 of the first region 2 and the width W2 of the second region 3 within appropriate predetermined ranges, for example, as shown in FIG. A large longitudinal vortex LV can be generated near the boundary with the region, and the effect of the longitudinal vortex LV (i.e., the flow of gas F is separated from the surface of the fluid resistance reduction film 1) in the entire boundary layer (thickness δ). It is possible to produce an effect that suppresses the

Next, the first region and the second region of the fluid resistance reducing film of the present disclosure will be explained.

In the fluid resistance reduction film of the present disclosure, the length of the first region 2 (the length in the fluid resistance reduction film shown in FIG. 1) in the direction in which the first region 2 extends (direction d2 in the fluid resistance reduction film 1 shown in FIG. 1). For example, L1) is preferably 30 mm or more, and more preferably 50 mm or more. If the length of the first region 2 in the direction in which the first region 2 extends is too short, it becomes difficult to generate longitudinal vortices near the boundary between the first region 2 and the second region 3 adjacent to the first region 2, and the fluid The effect of suppressing flow separation may be reduced.
On the other hand, since the length of the first region 2 in the direction in which the first region 2 extends is 50 mm or more, the longitudinal vortex LV is generated near the boundary between the first region 2 and the second region 3 adjacent to the first region 2. It can be generated efficiently and reliably.
Although there is no particular restriction on the upper limit of the length of the first region 2 in the direction in which the first region 2 extends, it is preferably 1000 mm or less, for example, from the viewpoint of ease of handling when pasting on the surface of an object. .

Here, the length of the first region 2 in the direction in which the first region 2 extends is, for example, as shown in FIG. 5(a), when the surface of the fluid resistance reduction film 1 is a curved surface, It refers to the length of the first region 2 in the direction in which the first region 2 extends (L1 shown in FIG. 5(a)).

In addition, in the fluid resistance reduction film of the present disclosure, the height of the convex portion (height H1 of the convex portion 11 in the fluid resistance reduction film 1 shown in FIG. 1(a)) is equal to the thickness δ of the boundary layer shown in FIG. It is preferably about 1/100 or more and 1/10 or less. Note that the faster the fluid flow rate, the thinner the boundary layer thickness δ becomes.

For example, the height of the convex portion is preferably 20 μm or more and 400 μm or less, more preferably 50 μm or more and 200 μm or less. As mentioned above, for example, in moving objects such as automobiles, trains, and aircraft, in pipes such as ducts and gas pipes, and objects such as wind turbines and air conditioning equipment, the flow velocity of gas flowing through objects is 3 m/s or more and 250 m/s. (approximately 10 km/h or more and 900 km/h or less). When applying the fluid resistance reducing film of the present disclosure to the surfaces of these objects, by appropriately adjusting the height of the convex portion within the above range, the first region 2 and the second region 3 adjacent to the first region 2 can be It is possible to easily generate longitudinal vortices LV near the boundary.

Further, in the fluid resistance reduction film according to the present disclosure, the width of the first region 2 in the first direction d1 (width W1 in the fluid resistance reduction film 1 shown in FIG. 1(a)) is the same size as the thickness δ of the boundary layer. It is preferable that For example, the width of the first region 2 in the first direction d1 is preferably 0.2 mm or more and 50 mm or less, and more preferably 1 mm or more and 25 mm or less. Since the width of the first region 2 in the first direction d1 is within the above range, a large longitudinal vortex LV is generated near the boundary between the first region 2 and the second region 3 adjacent to the first region 2, and A longitudinal vortex LV can be generated throughout the layer.

Further, in the fluid resistance reduction film according to the present disclosure, the width of the second region 3 in the first direction d1 (width W2 in the fluid resistance reduction film 1 shown in FIG. 1(a)) is the width of the second region 3 in the first direction d1. Although the width may be the same as or different from the width of the first region 2 in the first direction d1, it is preferably the same as the width of the first region 2 in the first direction d1. If the width of the second region 3 in the first direction d1 is about the same as the width of the first region 2 in the first direction d1, the first region 2 and the second region adjacent to the first region 2 A larger longitudinal vortex LV is generated near the boundary of region 3, and the longitudinal vortex LV can be effectively generated in the entire boundary layer.

Here, when the surface of the fluid resistance reduction film 1 is a curved surface, the width of the first region 2 in the first direction d1 is, for example, as shown in FIG. 5(b). This refers to the width of the first region 2 (W1 shown in FIG. 5(a)). The same applies to the width of the second region 3 in the first direction d1.

In the fluid resistance reduction film 1 shown in FIGS. 1 and 2, the shape of the convex portions 11 arranged in the first region 2 is illustrated as extending linearly along the first direction. Without limitation, in the fluid resistance reduction film of the present disclosure, the shape of the convex portion 11 prevents the fluid resistance reduction film from being damaged even when the first region 2 and the second region 3 are stretched in a direction in which the first region 2 and the second region 3 extend in a strip shape. It is possible to take various forms that can reduce fluid resistance. For example, the pattern shape of the convex portion in plan view includes various patterns such as a line shape and a dot shape.
Examples of the linear pattern include linear, polygonal, and curved patterns.

Note that the above-mentioned "linear pattern" refers to a pattern that has a longitudinal straight portion along a specific direction in plan view. Moreover, "a form extending linearly along the first direction" is a form having a longitudinal linear portion along the first direction in plan view.

For example, like the convex portion 11 shown in FIG. 2, a shape of a rectangular parallelepiped extending along the first direction d1 is applicable. However, the shape does not have to be strictly a rectangular parallelepiped; for example, in plan view, the portions other than the longitudinal linear portions along the first direction may be formed in curved lines. The cross-sectional shape may also be trapezoidal or the like other than rectangular. Furthermore, the longitudinal linear portion along the first direction does not need to be strictly straight, and may have irregularities or distortions depending on the material or manufacturing process.

In the present disclosure, "a form extending linearly along the first direction" refers to, for example, a cylindrical plate rotating along the first direction d1 in the method for manufacturing a fluid resistance reducing film of the present disclosure (FIG. 12), which will be described later. It is preferable that the shape has linearity to the extent that the mold releasability is not impaired.

Further, in the fluid resistance reduction film 1 shown in FIGS. 1 and 2, a linear pattern is exemplified as the pattern shape of the convex portion 11 in plan view, and the longitudinal direction of the linear pattern is oriented along the first direction d1. However, the longitudinal direction of the linear pattern of the convex portions 11 in the fluid resistance reduction film of the present disclosure is the direction in which the fluid resistance reduction film intersects the first direction d1. The direction can be such that the convex portion 11 can be prevented from being damaged even when stretched, and the fluid resistance reduction film can reduce fluid resistance.

For example, the longitudinal direction of the linear pattern of the convex portion 11 can be within an angular range of 0°±30° with respect to the first direction d1, within a range where fluid resistance can be reduced.
As will be described later, when shaping the convex portions 11 using a cylindrical plate, the longitudinal direction of the linear pattern extends along the first direction d1, that is, the linear pattern of the convex portions 11 is formed. It is preferable that the longitudinal direction of is substantially parallel to the first direction d1. Here, the expression that the longitudinal direction of the linear pattern of the convex portion 11 is approximately parallel to the first direction d1 means that the angle between the longitudinal direction of the linear pattern and the first direction d1 is 0°. It means ±5°.

In addition, in the fluid resistance reduction film 1 shown in FIGS. 1 and 2, the cross-sectional form of the convex portions 11 arranged in the first region 2 in the direction d2 is rectangular, but is not limited to this. However, in the fluid resistance reducing film of the present disclosure, the cross-sectional shape of the convex portion 11 in the direction d2 can be various shapes that can reduce fluid resistance. For example, in addition to a rectangular shape, examples include a trapezoidal shape, a triangular shape, a semicircular shape, a semielliptical shape, and a combination thereof.

When the convex portion 11 has a form extending linearly along the first direction d1, the width of the convex portion 11 in the direction orthogonal to the first direction d1 is 1 time or more and no more than 2 times the height H1 of the convex portion 11. It is preferable that If this width is too small, it may become difficult to form the convex portion 11. Moreover, if this width is too large, there is a possibility that the effect of reducing fluid resistance will not be sufficiently produced. On the other hand, if this width is one to two times the height H1 of the convex portion 11, the convex portion 11 can be formed more easily, and the effect of reducing fluid resistance can be sufficiently produced.
Here, the width of the convex portion 11 mentioned above is the largest width of the convex portion 11 in the direction orthogonal to the first direction d1 in plan view. For example, when the cross-sectional form of the convex part 11 in the direction perpendicular to the first direction d1 is trapezoidal, triangular, semicircular, semi-elliptical, etc., the largest width is usually the width of the bottom of the convex part 11. Become.

The interval between adjacent convex portions 11 in the direction in which the first region 2 extends is preferably 1 to 12 times the height H1 of the convex portions 11, and more preferably 5 times to 12 times.

In order to effectively reduce fluid resistance by generating a longitudinal vortex LV near the boundary between the first region 2 and the second region 3, the fluid that has once separated from the first surface due to collision with the convex portion 11 must be It is desirable that the phenomenon of approaching the first surface and colliding with the next convex portion 11 occurs continuously in the fluid flow direction. That is, it is desirable that the interval between adjacent convex portions 11 corresponds to the distance that the fluid, once separated from the first surface, approaches the first surface again.

Here, if the interval between adjacent protrusions 11 is less than one time the height H1 of the protrusions 11, the above distance is too short. Further, if the interval between adjacent convex portions 11 is greater than 12 times the height H1 of the convex portions 11, the above distance is too long. This distance is generally considered to be about eight times the height H1 of the convex portion 11.

Note that the interval between adjacent convex portions 11 in the direction in which the first region 2 extends corresponds to the width of the concave portion 12 in the direction in which the first region 2 extends.

Furthermore, in the fluid resistance reduction film according to the present disclosure, at least one of the plurality of convex portions arranged in the first region may have a shape different from the other convex portions. For example, at least one of the plurality of convex portions arranged in the first region may have a different height and width from the other convex portions.

Such a protrusion having a shape different from other protrusions can be used as a mark for positioning or product identification. Further, it can be manufactured more easily than when a separate mark is provided. Even if the convex portions used as such marks are small in size, they can be detected by forming them periodically in a specific direction, for example. Moreover, if the number of convex portions is small compared to other convex portions, the fluid control effect as a fluid resistance reducing film will not be reduced.
On the other hand, when providing a separate mark, an area for providing this mark is required, for example, on the first surface of the fluid resistance reduction film.

Further, in the fluid resistance reduction film according to the present disclosure, the recessed portions 12 of the uneven structure of the first region 2 may be recessed with respect to the first surface 10. For example, the fluid resistance reduction film 1A shown in FIG. 6 is an example in which the recessed portions 12 of the uneven structure 4 are recessed with respect to the first surface 10.

Moreover, in the fluid resistance reduction film according to the present disclosure, the pattern shape of the convex portions 11 included in the first region 2 in plan view may be dot-shaped.
For example, in the fluid resistance reduction film 1B shown in FIG. A plurality of them are arranged in the direction (first direction d1 shown in FIG. 7(a)) and in the direction in which the first region 2 extends (direction d2 shown in FIG. 7(a)).
Note that FIGS. 7(b) and 7(c) are sectional views taken along the line AA in FIG. 7(a), respectively.

In the fluid resistance reduction film 1B, since the contact area of the dot-shaped convex portions 11 is small, not only the direction in which the first region 2 extends (direction d2 shown in FIG. 7(a)) but also the width direction of the first region 2 The fluid resistance reduction film 1B can be stretched in all surface directions of the fluid resistance reduction film 1B including (the first direction d1 shown in FIG. 7(a)).

Further, since the ground contact area of the dot-shaped convex portions 11 is small, foreign matter is unlikely to accumulate between adjacent convex portions 11. Therefore, it also has the effect of suppressing a decrease in the fluid resistance reduction effect due to the accumulation of foreign matter.

In the fluid resistance reduction film 1B shown in FIG. 7(a), the plurality of dot-shaped convex portions 11 are arranged in the width direction of the first region 2 (the first direction d1 shown in FIG. 7(a)) and in the first direction d1 shown in FIG. 7(a). Although they are regularly arranged at regular intervals in the direction in which the regions 2 extend (direction d2 shown in FIG. 7(a)), the fluid resistance reducing film of the present disclosure is not limited thereto.
For example, the plurality of dot-shaped convex portions 11 are arranged in the width direction of the first region 2 (first direction d1 shown in FIG. 7(a)) and in the direction in which the first region 2 extends (direction d2 shown in FIG. 7(a)). ) may be arranged randomly.

Furthermore, the shapes of the plurality of dot-shaped convex portions 11 may be the same or different. For example, the height, ground contact area, etc. of each of the plurality of dot-shaped convex portions 11 may be the same or different.

Further, in the fluid resistance reducing film according to the present disclosure, the pattern shape of the recesses 12 in the first region 2 in plan view may be dot-like.
For example, in the fluid resistance reduction film 1C shown in FIG. 8, the pattern shape of the recesses 12 in the first region 2 in plan view is dot-like.
Note that FIG. 8(b) is a cross-sectional view taken along the line AA in FIG. 8(a).

In the fluid resistance reduction film 1C, since the opening area of the dot-shaped recesses 12 is small, not only the direction in which the first region 2 extends (direction d2 shown in FIG. 8(a)) but also the width direction of the first region 2 ( The fluid resistance reduction film 1C can be stretched in all surface directions of the fluid resistance reduction film 1C including the first direction d1) shown in FIG. 8(a).

Moreover, since the dot-shaped recesses 12 do not protrude from the first surface of the fluid resistance reduction film 1C, it is expected that the scratch resistance will be improved. In particular, this effect can be expected because the opening area of the dot-shaped recesses 12 is small.

In the fluid resistance reduction film 1C shown in FIG. 8(a), the plurality of dot-shaped recesses 12 are arranged in the width direction of the first region 2 (the first direction d1 shown in FIG. 8(a)) and in the first region 2 (direction d2 shown in FIG. 8A), the fluid resistance reducing film of the present disclosure is not limited to this.
For example, the plurality of dot-shaped recesses 12 are formed in the width direction of the first region 2 (first direction d1 shown in FIG. 8(a)) and in the direction in which the first region 2 extends (direction d2 shown in FIG. 8(a)). They may also be arranged randomly.

Furthermore, the shapes of the plurality of dot-shaped recesses 12 may be the same or different. For example, the depth, opening area, etc. of each of the plurality of dot-shaped recesses 12 may be the same or different.

Further, in the fluid resistance reduction film according to the present disclosure, a structure that exhibits the effect of reducing fluid resistance may be provided in the second region 3. For example, in the fluid resistance reduction film 1 shown in FIG. 1(a), the second region 3 has a groove structure extending along the direction in which the second region 3 extends (direction d2 shown in FIG. 1(a)). It's okay. A plurality of groove structures may be arranged in parallel in the width direction of the second region 3 (first direction d1 shown in FIG. 1(a)). For example, this parallel spacing can be on the order of tens of microns.

By providing such a groove structure in the second region 3, the frictional resistance of the fluid can be reduced. In particular, periodic grooves (ribblet structure) with intervals of several tens of microns are highly effective in reducing fluid frictional resistance.

2. Structure of Film The fluid resistance reducing film in the present disclosure can have at least a resin base material. The fluid resistance reduction film in the present disclosure only needs to have a fluid resistance reduction structure on the first surface. For example, the fluid resistance reduction structure may be configured separately from the resin base material, or the fluid resistance reduction structure may be configured separately from the resin base material. It may be configured integrally with the base material.

When the fluid resistance reducing structure is configured separately from the resin base material, examples of the material for the fluid resistance reducing structure include a curable resin composition and a thermoplastic resin. Examples of the curable resin composition include ionizing radiation curable resin compositions such as ultraviolet ray curable resin compositions and electron beam curable resin compositions, thermosetting resin compositions, and the like.
When the fluid resistance reducing structure is configured integrally with the resin base material, the material of the fluid resistance reducing structure can be the same as the material of the resin base material.

As the material for the resin base material, for example, a thermoplastic resin can be used, and it can be appropriately selected from general-purpose plastics and engineering plastics. Among these, vinyl chloride resin is preferred from the viewpoint of weather resistance and abrasion resistance.

The resin base material may contain additives such as plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, ultraviolet absorbers, antioxidants, antistatic agents, twist retardants, etc., as necessary. It's okay.

The thickness of the resin base material is not particularly limited, and is appropriately selected depending on the use of the fluid resistance reducing film. For example, when the fluid resistance reducing film of the present disclosure is used as a wrapping film or marking film for moving objects such as automobiles, trains, and airplanes, the thickness of the resin base material can be approximately 80 μm or more and 350 μm or less. .

Note that the shape of the fluid resistance reducing film of the present disclosure in plan view is not particularly limited, and is appropriately selected depending on the application and the like. The shape of the fluid resistance reduction film of the present disclosure in plan view may be a simple geometric shape such as a rectangular shape, a circular shape, an elliptical shape, a polygonal shape, etc., or it may be a complex shape. .

Here, in the fluid resistance reducing film according to the present disclosure, the extent of elongation in the first direction on the first surface is smaller than the extent of elongation in the direction in which the first region and the second region extend in a strip shape. Further, in the fluid resistance reducing film according to the present disclosure, it is more preferable that the amount of elongation in the first direction on the first surface is smaller than the amount of elongation on the first surface in a direction intersecting the first direction. In other words, in the fluid resistance reducing film of the present disclosure, it is more preferable that the amount of elongation in the first direction on the first surface is smaller than the amount of elongation on the first surface in any other direction.
By having such characteristics, the fluid resistance reduction film according to the present disclosure can be applied to the surface of an object to effectively reduce fluid pressure resistance, even if the object has a curved surface.

Here, the above-mentioned "elongation" refers to the amount of deformation when a tensile force is applied to the material. More specifically, when the original length is L and the amount of elongated deformation is ΔL, this ΔL is referred to as "elongation."
For example, to compare the magnitude of "elongation" in each direction of the fluid resistance reducing film in the present disclosure, a tensile test is performed using a tensile tester or the like at the same tensile force and speed in each direction, and It can be obtained by comparing the magnitude of the amount of deformation. In comparing the magnitude of this "elongation", it is not necessary to break the sample (fluid resistance reducing film), and it is sufficient to compare the magnitude of the amount of deformation due to elongation before breaking. It is sufficient if this effect is confirmed at least in the elastic region.

Further, the magnitude of "elongation" in each direction of the fluid resistance reducing film in the present disclosure may be evaluated by tensile modulus. The tensile modulus is determined by JIS K7161-1:2014 (Plastics - How to determine tensile properties - Part 1: General rules) and JIS K7127:1999 (Plastics - Test methods for tensile properties - Part 3: Measurement conditions for films and sheets) ). In this case, for example, a tensile modulus in each direction is measured by performing a tensile test on each direction of the sample (film-like gas resistance reducing structure) using a tensile tester. The conditions for the tensile test and the details of the tensile test are described in the Examples section below.

For example, when the convex part 11 has a form extending linearly along the first direction as in the fluid resistance reducing film 1 shown in FIGS. 1 and 2, the fluid resistance reducing film 1 is Preferably, the size is small. When the convex portions 11 are made of a material that does not have flexibility against stretching, when the fluid resistance reduction film 1 is stretched in the first direction d1, the convex portions 11 cannot withstand the stretching and may collapse or peel. This is because there is a risk that this may occur.

Here, in the direction d2 in which the first region 2 extends, even if the fluid resistance reduction film 1 is stretched, the concave portions between the plurality of arranged convex portions 11 are stretched. In comparison, there is less risk of the convex portion 11 collapsing or peeling off.

Therefore, in the fluid resistance reducing film according to the present disclosure, it is preferable that the amount of elongation in the first direction on the first surface is smaller than the amount of elongation on the first surface in the direction d2 in which the first region 2 extends.

Furthermore, for example, many trucks, buses, trains, etc. have corners that connect from a flat front part that is approximately perpendicular to the ground to a flat side part that is also approximately perpendicular to the ground. This corner usually has a small radius of curvature.
In a portion including such a corner, air, which is a fluid, flows from the front portion toward the side portion. Therefore, when applying the fluid resistance reduction film 1 shown in FIG. 1, the first region 2 and the second region 3 It is preferable that the pasting is performed so that the extending direction d2 coincides with the air flow direction. For example, the fluid resistance reduction film 1 is attached such that the direction d2 in which the first region 2 and the second region 3 extend is a direction from the front portion to the side portion along the curved surface of the corner with a small radius of curvature. For example, FIG. 9 shows an example in which the fluid resistance reducing film 1 is applied to the above-mentioned corresponding locations on the track.

At this time, the fluid resistance reducing film 1 may be stretched in the direction d2 in which the first region 2 and the second region 3 extend along the curved surface of the corner having a small radius of curvature. Therefore, it is preferable that the fluid resistance reducing film 1 has a certain degree of elongation in the direction d2 in which the first region 2 and the second region 3 extend, in order to facilitate attachment.
On the other hand, since the first direction d1 is not particularly stretched, it is not required that the stretch be particularly large.

In order to create such a fluid resistance reduction film, the resin base material constituting the fluid resistance reduction film must have a smaller elongation in a specific direction than the elongation in a direction that intersects with that specific direction. is preferred. An example of such a resin base material is a uniaxially stretched resin base material. For example, in a uniaxially stretched resin base material, the magnitude of elongation in the stretched direction is smaller than the magnitude of elongation in the direction crossing the stretched direction.
Furthermore, although it depends on the material of the resin base material, not only uniaxial stretching but also biaxial stretching is used, the magnitude of elongation in the MD (Machine Direction) direction is usually the same as the magnitude of the elongation in the TD (Transverse Direction) direction in the manufacturing process. It becomes smaller compared to the size of the elongation. For example, such a resin base material includes a biaxially stretched PET (polyethylene terephthalate) resin base material. Therefore, even in a biaxially stretched resin base material, the amount of elongation in one direction is smaller than the amount of elongation in the one direction, for example, the amount of elongation in the MD direction is smaller than the amount of elongation in the TD direction. Any resin base material that has a smaller elongation than the other one that intersects with can be used as the resin base material constituting the fluid resistance reduction film of the present disclosure.
In the present disclosure, it is sufficient that the produced fluid resistance reducing film has an elongation in the first direction d1 that is smaller than an elongation in the direction d2 intersecting the first direction. Therefore, the resin base material used does not necessarily need to be limited to a resin base material whose elongation in the first direction d1 is smaller than the elongation in the direction d2 intersecting the first direction. For example, the resin base material may have the same elongation size in the first direction d1 as the elongation size in the direction d2 that intersects the first direction. However, the resin base material may have a larger elongation than the elongation in the direction d2 intersecting the first direction.

3. Laminated Structure The fluid resistance reduction film in the present disclosure may have a laminated structure in which other layers are laminated. For example, another layer may be provided on the side opposite to the first surface. Examples of other layers include an adhesive layer, a printed layer, and the like.

(adhesive layer)
The fluid resistance reduction film according to the present disclosure may have an adhesive layer 21 on the side opposite to the first surface, for example, as shown in FIG. 10(a). The adhesive layer is a layer for attaching the fluid resistance reducing film to the surface of an object. By having an adhesive layer, the fluid resistance reducing film can be easily attached to the surface of an object.
The adhesive used in the adhesive layer is appropriately selected depending on the application, and examples thereof include acrylic adhesives, urethane adhesives, silicone adhesives, rubber adhesives, vinyl ether adhesives, and the like.

Although the adhesive layer may or may not have removability, it is particularly preferable to have removability. If the adhesive layer has removability, it can be reapplied when attaching the fluid resistance reduction film to the surface of an object, and it will not leave any adhesive residue when replacing or removing the fluid resistance reduction film. It is possible to peel the fluid resistance reduction film from an object without causing any damage.
Note that "repeelability" refers to the property that after a fluid resistance reducing film is attached to the surface of an object, it can be easily peeled off without destroying the object and without leaving any adhesive on the surface of the object.

The thickness of the adhesive layer is not particularly limited, and is appropriately selected depending on the use of the fluid resistance reducing film. For example, the thickness of the adhesive layer can be about 5 μm or more and 50 μm or less.

Examples of the method for forming the adhesive layer include a method of applying an adhesive composition and a method of laminating an adhesive film.

(Printing layer)
The fluid resistance reduction film in the present disclosure may have a printed layer on the side opposite to the first side. When the fluid resistance reduction film has a printed layer, it is possible to impart design properties to the film. The printing layer can display information such as letters, numbers, symbols, pictures, patterns, and marks, for example.

As a method for forming the printed layer, for example, the printed layer may be formed by directly printing on the resin base material of the fluid resistance reduction film, or, for example, as shown in FIG. The printed layer 23 may be formed by printing on the layer 22. The printing layer may be arranged in a pattern on the resin base material or the support layer, or may be arranged on the entire surface of the resin base material or the support layer. Furthermore, the printing method is not particularly limited.

The support layer is not particularly limited as long as it can be printed, and for example, a resin base material can be used.
The support layer may contain a colorant. By containing the colorant in the support layer, shielding properties can be imparted. For example, if a design is applied to the surface of the article, and the fluid resistance reduction film has a printed layer and the support layer contains a colorant, the fluid resistance reduction film may be attached to the surface of the article. Then, you can hide that design and create a new design.
The thickness of the support layer is not particularly limited, and is appropriately selected depending on the use of the fluid resistance reducing film.

In addition, when forming a printed layer by printing on the support layer, for example, as shown in FIG. A printed sheet having the above structure may be separately produced, and this printed sheet may be bonded to the resin base material of the fluid resistance reduction film via the second adhesive layer 24.

4. Applications The fluid resistance reduction film of the present disclosure can be applied to the surface of an object. The surface of the object may be a flat surface or a curved surface.

Specifically, the fluid resistance reduction film of the present disclosure can be applied to automobiles such as passenger cars, trucks, and buses, railway vehicles such as trains, Shinkansen trains, and locomotives, aircraft such as airplanes, helicopters, and drones, and gaseous vehicles such as bicycles. It can be applied to the surface of the casing or parts of a moving object that moves inside.
Furthermore, the fluid resistance reduction film of the present disclosure can be applied to, for example, the inner surfaces of pipes such as ducts and gas pipes, the surfaces of windmill blades, and the surfaces of air outlets and louvers of air conditioning equipment such as air conditioners. can.

Among these, the fluid resistance reduction film of the present disclosure is preferably applied to the surface of a housing or parts of a moving body, and is preferably applied to the surface of a moving body that is a non-streamlined object, specifically a bluff body. It is preferable to apply. This is because in a bluff body, pressure resistance makes a large contribution to fluid resistance, and the effects of the present disclosure are significantly exhibited. Examples of moving objects that are bluff bodies include trucks, buses, trains, and the like.

When applying the fluid resistance reducing film of the present disclosure to the surface of an object, the film is arranged so that the angle between the extending direction of the second region 3 of the fluid resistance reducing film and the fluid flow direction is, for example, 0°±15°. It is preferable to do so. Among these, it is preferable that the second region 3 of the fluid resistance reducing film is arranged so that the direction in which it extends is parallel to the flow direction of the fluid. As a result, longitudinal vortices LV are likely to be generated near the boundary between the first region 2 and the second region 3 adjacent to the first region 2, effectively suppressing separation of the fluid flow from the surface of the object. can do.

[Roll body]
Next, the roll body of the present disclosure will be explained. The roll body of the present disclosure is a roll body in which the fluid resistance reduction film of the present disclosure is wound up, and the fluid resistance reduction film of the present disclosure is wound in a first direction.

Generally, in order to mass-produce films, it is preferable to use a roll-to-roll method. The fluid resistance reducing film of the present disclosure is also preferably wound up as a roll during manufacturing and transportation.
However, it is important that the winding direction is a direction that matches the characteristics of the fluid resistance reducing film of the present disclosure. Regarding the winding direction, it is preferable that the elongation of the fluid resistance reducing film in the winding direction is small so as not to be adversely affected even if a tensile force acts on the fluid resistance reducing film.

The fluid resistance reducing film of the present disclosure can meet such requirements by setting the winding direction when forming a roll into the first direction of the fluid resistance reducing film. By forming the fluid resistance reducing film of the present disclosure into a roll, it can be made into a form more suitable for mass production and transportation than a sheet form.

FIG. 11 is a diagram showing an example of a roll body of the present disclosure. The roll body 30 shown in FIG. 11 is a roll body in which the fluid resistance reducing film 1 is wound around a winding core 31. In the roll body 30, the fluid resistance reduction film 1 is wound up along the first direction d1.
In the example shown in FIG. 11, the fluid resistance reducing film 1 has a web-like form that is elongated along the first direction d1.

As described above, in the fluid resistance reduction film 1, the amount of elongation in the first direction d1 on the first surface 10 is smaller than the amount of elongation in the direction d2 in which the first region 2 and the second region 3 extend in a strip shape. . Therefore, when forming the roll body 30, by winding up the fluid resistance reducing film 1 along the first direction d1, it is possible to prevent the fluid resistance reducing film 1 from stretching excessively.

On the other hand, for example, in a roll body in which the fluid resistance reducing film 1 is wound up along the direction d2 in which the first region 2 extends, such as the roll body 100 shown in FIG. Since the amount of elongation in the direction d2 is larger than the amount of elongation in the first direction d1, there is a risk that the fluid resistance reducing film 1 may be excessively elongated during winding into the roll body 100.
In the example shown in FIG. 12, the fluid resistance reducing film 1 has a web-like form that is elongated along the direction d2 in which the first region 2 and the second region extend in a strip shape.
Then, by holding the fluid resistance reducing film 1 in the state of the roll body 100 (that is, holding the fluid resistance reducing film 1 in a state excessively stretched in the direction d2), the fluid unwound from the roll body 100 In the resistance reducing film 1, there is a possibility that the elongation in the direction d2 has already become small. In addition, in the fluid resistance reduction film 1 whose elongation in the direction d2 has become small, the effect when applied to the corner connecting from the front part to the side part of the above-mentioned truck, bus, train, etc. is lost. Become.

In addition, in roll bodies, it is necessary to suppress the phenomenon in which the films being wound stick together (called blocking) and the phenomenon in which winding wrinkles occur due to uneven film thickness. The roll body of the present disclosure is also effective in solving the problems.

For example, in a roll body such as a roll body 100 shown in FIG. 12 in which the fluid resistance reducing film 1 is wound up along the direction in which the first region 2 extends (direction d2 shown in FIG. 12), the first region 2 The position of the second region 3 is always the same in the direction in which the winding core 101 extends (the first direction d1 shown in FIG. 12). That is, in the roll body 100, the first region 2 of the fluid resistance reduction film 1 wound closer to the inner circumference side and the first region 2 of the fluid resistance reduction film 1 wound closer to the outer circumference side are as follows. They overlap in the direction of the winding diameter. If this continues for hundreds of layers, the risk of blocking and curling wrinkles will increase.

On the other hand, for example, in a roll body in which the fluid resistance reduction film 1 is wound up along the first direction d1 like the roll body 30 shown in FIG. The position of the second region 3 is shifted according to the distance from the winding core 31 (winding diameter). That is, the first region 2 of the fluid resistance reduction film 1 wound more toward the inner circumference and the first region 2 of the fluid resistance reduction film 1 wound more toward the outer circumference have different positions in the direction of the winding diameter. will be shifted. At least in the direction of the winding diameter, the first regions 2 do not overlap at the same position over hundreds of layers.
Therefore, in the roll body 30, phenomena such as blocking and winding wrinkles can be suppressed.

Note that in the roll body of the present disclosure, the fluid resistance reducing film being wound up may have other layers on the first surface and on the surface opposite to the first surface. For example, a protective layer may be provided on the first surface, and a back layer may be provided on the surface opposite to the first surface. The above-mentioned protective layer and back layer can be provided, for example, by a method of laminating a protective film and a back film with a fluid resistance reducing film.

[Method for manufacturing fluid resistance reduction film]
Next, a method for manufacturing the fluid resistance reducing film of the present disclosure will be described.
In the present disclosure, the method for forming the uneven structure formed in the first region of the fluid resistance reduction film may be, for example, a method of forming the uneven structure on the resin base material, and the uneven structure may be formed on one side of the resin base material. A method of forming an uneven shape on the surface may also be used.

Examples of methods for forming an uneven structure on a resin base material include a method using a curable resin composition, applying the curable resin composition onto the resin base material in a predetermined pattern and curing it, and Using a curable resin composition, apply the ultraviolet curable resin composition onto a resin base material, press a mold against the coating film, and cure the ultraviolet curable resin composition by irradiating it with ultraviolet rays. Using the so-called photopolymer method (2P method) in which the ionizing radiation-curable resin composition is peeled off from the mold, the ionizing radiation-curable resin composition is applied onto the resin base material, and ionizing radiation such as ultraviolet rays or electron beams is applied. Examples include a so-called lithography method in which radiation is irradiated in a pattern and developed, and a method in which a resin layer is formed on a resin base material and the surface of the resin layer is embossed.
Alternatively, a resin layer with an embossed surface may be separately produced and the resin layer may be laminated onto the resin base material.

In the case of a method of applying a curable resin composition on a resin base material in a predetermined pattern and curing it, the method of applying the curable resin composition may be any method that can apply the curable resin composition in a desired pattern. The method is not particularly limited, and examples thereof include an inkjet method, a screen printing method, and the like. In addition, in the case of the photopolymer method or the lithography method, the method of applying the curable resin composition is not particularly limited as long as it can be applied uniformly, and any known application method may be applied. I can do it.

Furthermore, in the case of the embossing method, the material for the resin layer is not particularly limited as long as it is capable of embossing, and thermoplastic resins can be used. In this case, the thickness of the resin layer is not particularly limited as long as it is larger than the height of the uneven structure, and is appropriately selected depending on the use of the fluid resistance reducing film. For example, when the fluid resistance reducing film of the present disclosure is used as a wrapping film or marking film for a moving body such as a car, train, or aircraft, the thickness of the resin layer can be about 30 μm or more and 300 μm or less.

Further, as a method for forming an uneven shape on one side of the resin base material, for example, a method of embossing one or both sides of the resin base material can be mentioned.

Here, as mentioned above, in order to mass produce a film, it is generally preferable to produce it by a roll-to-roll method. Also in the fluid resistance reducing film of the present disclosure, in order to mass produce it, it is preferable to produce it by a roll-to-roll method.
When producing the fluid resistance reducing film of the present disclosure using a roll-to-roll method, for example, a manufacturing method including the following steps of preparing a base material, forming a fluid resistance reducing structure, and winding up the film may be used. can.

First, in the base material preparation step, a resin base material whose elongation in the first direction d1 is smaller than the elongation in the direction d2 intersecting the first direction is used as the resin base material constituting the fluid resistance reduction film. prepare.
In the present disclosure, it is sufficient that the produced fluid resistance reducing film has an elongation in the first direction d1 that is smaller than an elongation in the direction d2 intersecting the first direction. Therefore, the resin base material prepared in this base material preparation step is limited to a resin base material whose elongation in the first direction d1 is smaller than the elongation in the direction d2 intersecting the first direction. There is no need to be done. For example, the resin base material may have the same elongation size in the first direction d1 as the elongation size in the direction d2 that intersects the first direction. However, the resin base material may have a larger elongation than the elongation in the direction d2 intersecting the first direction.
Next, in a fluid resistance reduction structure forming step, first regions and second regions extending in a direction d2 intersecting the first direction d1 are alternately formed in the first direction on the first surface of the resin base material. Here, "forming a first region and a second region" specifically refers to a state in which the above-mentioned specific uneven structure is formed in the first region so that the first region and the second region can be distinguished. It means to do.
Thereafter, in a winding step, the fluid resistance reducing film in which the first region and the second region are formed is wound in a first direction.

Through such steps, the fluid resistance reducing film of the present disclosure can be manufactured with high productivity by a roll-to-roll method.
Further, in the winding step, the roll body of the present disclosure can be obtained by setting the winding direction when forming the roll body to the first direction d1 of the fluid resistance reduction film. Note that the effects of the roll body of the present disclosure have been described in detail in the description of the roll body of the present disclosure, so detailed description thereof will be omitted here.

In the method for manufacturing a fluid resistance reducing film of the present disclosure, the above-mentioned specific uneven structure may be formed in the first region using a cylindrical plate. For example, a cylindrical plate can be used in the photopolymer method or embossing method described above. Using cylindrical plates is preferred for mass production.

In particular, when the fluid resistance reduction film of the present disclosure has a form in which the convex portions 11 extend linearly along the first direction d1, like the fluid resistance reduction film 1 shown in FIGS. The resistance reduction structure forming step includes a step of forming a convex portion 11 having a shape extending linearly along the first direction d1 in the first region 2 using a cylindrical plate rotating along the first direction d1. It is preferable to include.
By making the rotation direction of the cylindrical plate the same as the longitudinal direction of the convex portion 11 (first direction), the convex portion 11 will be destroyed when the formed convex portion 11 is released from the cylindrical plate. This can be suppressed. That is, formation of defective convex portions 11 can be reduced.

The above will be explained in more detail using FIGS. 13 and 14. Here, FIG. 13 is a schematic diagram illustrating an example of the method for manufacturing the fluid resistance reducing film of the present disclosure. Moreover, FIG. 14 is a schematic diagram explaining an example of the manufacturing method of another fluid resistance reduction film.

For example, as shown in FIG. 14, a cylindrical plate 110 rotating along the direction d2 in which the first region 2 extends is used to apply the cylindrical plate 110 to the first region 2 of the fluid resistance reduction film 1 along the first direction d1. When forming the convex portion 11 having a linearly extending form, the direction in which the fluid resistance reducing film 1 flows (direction d2) due to rotation of the cylindrical version 110 is different from the longitudinal direction of the convex portion 11 (first direction d1). Therefore, when the formed protrusion 11 is released from the cylindrical version 110, the resistance received from the cylindrical version 110 is large, and therefore, the protrusion 11 may be destroyed by the cylindrical version 110.
In the example shown in FIG. 13, the fluid resistance reducing film 1 has a web-like form that is elongated along the direction d2 in which the first region 2 and the second region extend in a strip-like manner.

On the other hand, as shown in FIG. 13, a shape extending linearly along the first direction d1 is formed in the first region 2 of the fluid resistance reduction film 1 using the cylindrical plate 40 rotating along the first direction d1. When forming a convex portion 11 having a cylindrical plate 40, the direction in which the fluid resistance reducing film 1 flows due to rotation of the cylindrical plate 40 and the longitudinal direction of the convex portion 11 are the same direction (first direction d1). When the cylindrical version 11 is released from the cylindrical version 40, the resistance received from the cylindrical version 40 is small, and therefore, the protrusion 11 is prevented from being destroyed by the cylindrical version 40.
In the example shown in FIG. 13, the fluid resistance reducing film 1 has a web-like form that is elongated along the first direction d1.

Hereinafter, the present disclosure will be further explained by showing Examples and Comparative Examples.

[Examples 1 to 7]
A roll of a long uniaxially stretched vinyl chloride resin film is prepared, and a UV curable resin is applied onto the vinyl chloride resin film unwound from the roll. While shaping the UV curable resin with a cylindrical plate, it is cured by UV irradiation to form an uneven structure having a plurality of linear protrusions along the direction of uniaxial stretching of the vinyl chloride resin film, and this is rolled. I took it and got a rolled body. Next, a long film was unwound from the rolled roll body and cut into sheets to produce a fluid resistance reducing film having the configuration shown in FIG. 1. The dimensions of each component of the fluid resistance reducing film were as shown in Table 1.

[Evaluation 1]
The fluid resistance reducing films of Examples 1 to 7 were applied from the front part of a box-shaped model (length 1250 mm, width 260 mm, height 387 mm) to the side part through the corners to the area where the uneven structure was formed. (first area shown in FIG. 1) was attached so that the direction in which it extends matched the direction in which gas flows, a wind tunnel experiment was conducted, and the air resistance coefficient (Cd value) was measured at a wind speed of 25 m/s. The results are shown in Table 1.
On the other hand, as Comparative Example 1, the air resistance coefficient (Cd value) was measured in the same manner as above for the above model to which the fluid resistance reduction film was not attached. The results are shown in Table 1.

As shown in Table 1, it was confirmed that in Examples 1 to 7, the Cd value was smaller than in Comparative Example 1, and the air resistance was reduced.

[Example 8]
As a resin base material, a laminate in which a laminate film was laminated on a printing original fabric ("IJ180 mc-114" manufactured by 3M Company) having a transparent base material was prepared. A laminate film ("DOL1460Z" manufactured by Avery Dennison) that has a vinyl chloride resin film, an adhesive layer, and a release paper in this order is used as the laminate film, and after peeling off the release paper from the laminate film, the laminate film is laminated onto the printing material. The film was laminated.
Next, a UV curable ink ("Seikabeam HT509" manufactured by Dainichiseika Chemical Co., Ltd.) is ejected and cured onto the vinyl chloride resin film of the laminate film using a UV inkjet device to form a plurality of linear convex portions and A fluid resistance reducing film having the configuration shown in FIG. 1 was produced by forming an uneven structure having depressions.
The height of the uneven portion of the fluid resistance reducing film was 140 μm, the width of the first region and the width of the second region were each 7 mm, and the interval between the convex portions of the uneven structure was 1120 μm.

[Example 9]
In the same manner as in Example 8, a laminate was prepared in which a laminate film was laminated on a printing original fabric ("IJ180 mc-114" manufactured by 3M Company) having a transparent base material as a resin base material. A laminate film ("DOL1460Z" manufactured by Avery Dennison) that has a vinyl chloride resin film, an adhesive layer, and a release paper in this order is used as the laminate film, and after peeling off the release paper from the laminate film, the laminate film is laminated onto the printing material. The film was laminated.
Next, a UV curable resin composition ("Seikabeam HT509" manufactured by Dainichiseika Chemical Co., Ltd.) was applied onto the vinyl chloride resin film of the laminate film. Subsequently, a mold in which the shape of the desired uneven structure was reversed was pressed against the film of the UV curable resin composition, and the film of the UV curable resin composition was cured by UV irradiation. As a result, a concavo-convex structure having a plurality of linear convex portions and concave portions was formed, and a fluid resistance reducing film having the configuration shown in FIG. 1 was produced.
The height of the uneven portion of the fluid resistance reducing film was 140 μm, the width of the first region and the width of the second region were each 7 mm, and the interval between the convex portions of the uneven structure was 1120 μm.

[Comparative example 2]
The resin base material used in Example 8 and Example 9 was used as the film of Comparative Example 2. That is, the film of Comparative Example 2 is a laminate in which a laminate film is laminated on a printing material having a transparent base material ("IJ180 mc-114" manufactured by 3M), and the laminate film includes a vinyl chloride resin film. Using a laminate film ("DOL1460Z" manufactured by Avery Dennison) having an adhesive layer and a release paper in this order, the release paper was peeled off from the laminate film, and then the laminate film was laminated onto the printing material. Note that the film of Comparative Example 2 did not have a concavo-convex structure having a plurality of linear convex portions and concave portions.

[Evaluation 2]
The fluid resistance reducing films of Examples 8 and 9 and the film of Comparative Example 2 were tested under the following conditions in accordance with JIS K7161-1:2014 using "Instron 5565" manufactured by Instron Japan as a tensile tester. The tensile modulus in each direction was measured.

(Measurement condition)
・Test piece: length 150mm, width 25mm
・Distance between gauge lines: 75mm
・Tensile speed: 50mm/min
・Load cell: 1kN
・Number of measurements: 5

From a comparison between Examples 8 and 9 and Comparative Example 2, when the fluid resistance reduction structure of the present disclosure is provided, the tensile modulus in the MD direction is higher than that in the TD direction, and it tends to be difficult to stretch in the MD direction. It was shown that there is.

Although the embodiments of the fluid resistance reducing film, roll body, and method for manufacturing a fluid resistance reducing film according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. The above-mentioned embodiments are illustrative, and those having substantially the same configuration as the technical idea of the present disclosure and producing similar effects are included in the technical scope of the present disclosure in any case. .

1, 1A, 1B, 1C Fluid resistance reduction film 2 First region 3 Second region 4 Uneven structure 10 First surface 11 Convex portion 12 Concave portion 15 Track 21 Adhesive layer 22 Support layer 23 Print layer 24 Second adhesive layer 30 Roll Body 31 Winding core 40 Cylindrical version 41 Rotating shaft 100 Roll body 101 Winding core 110 Cylindrical version 111 Rotating shaft

Claims (9)

A fluid resistance reduction film having a fluid resistance reduction structure capable of reducing fluid resistance,
a first region having a concavo-convex structure composed of convex portions and concave portions on a first surface; and a second region adjacent to the first region;
The first region and the second region are alternately arranged in a first direction on the first surface,
The first region and the second region extend in a belt shape in a direction intersecting the first direction,
A fluid resistance reducing film, wherein an elongation in a first direction on the first surface is smaller than an elongation in a direction in which the first region and the second region extend in a band shape. The fluid resistance reduction film according to claim 1, wherein a plurality of the convex portions are arranged in a direction in which the first region extends. 3. The fluid resistance reduction film according to claim 2, wherein the distance between adjacent convex portions in the direction in which the first region extends is 1 to 12 times the height of the convex portions. The fluid resistance reduction film according to claim 3, wherein the convex portion has a form extending linearly along the first direction. 5. The width of the protrusion in a direction perpendicular to the first direction, which extends linearly along the first direction, is at least 1 time and at most 2 times the height of the protrusion. The fluid resistance reduction film described. The fluid resistance reduction film according to claim 5, wherein the length of the convex portion extending linearly along the first direction is 0.2 mm or more and 50 mm or less. A roll body, wherein the fluid resistance reducing film according to any one of claims 1 to 6 is wound up in the first direction. A method for producing a fluid resistance reducing film according to any one of claims 1 to 6, comprising:
a base material preparation step of preparing a resin base material constituting the fluid resistance reduction film;
a fluid resistance reduction structure forming step of forming alternately in the first direction the first region and the second region extending in a direction intersecting the first direction on the first surface of the resin base material; ,
a winding step of winding the fluid resistance reduction film in which the first region and the second region are formed in the first direction;
A method for producing a fluid resistance reducing film, comprising: A method for producing a fluid resistance reducing film according to any one of claims 4 to 6, comprising:
a base material preparation step of preparing a resin base material constituting the fluid resistance reduction film;
a fluid resistance reduction structure forming step of forming alternately in the first direction the first region and the second region extending in a direction intersecting the first direction on the first surface of the resin base material; ,
a winding step of winding the fluid resistance reduction film in which the first region and the second region are formed in the first direction;
Equipped with
The fluid resistance reduction structure forming step is a step of forming a convex portion having a shape extending linearly along the first direction in the first region using a cylindrical plate that rotates along the first direction. A method for producing a fluid resistance reduction film, comprising: