JP2022188898A - Uneven resin film and laminated film - Google Patents

Abstract

To provide an uneven resin film and a laminated film that can reduce pressure resistance.SOLUTION: Preferably, in an uneven resin film 1, uneven parts comprising a plurality of convex parts 11 and concave parts 12 and flat parts are alternately arranged in a first direction d1 in an uneven structure, the heights of the uneven parts are 20 μm or more and 200 μm or less, the lengths of the uneven parts in a second direction d2 orthogonal to the first direction are 30 mm or more, and the widths of the uneven parts and the widths of the flat parts in the first direction are 0.2 mm or more and 50 mm or less.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an uneven resin film and a laminated film capable of reducing gas resistance.

2. Description of the Related Art In recent years, in the fields of moving bodies that move in fluids, fluid transfer, and the like, research on fluid resistance reduction technology has been actively conducted in order to realize energy saving and carbon dioxide reduction.

Conventionally, as a technique for reducing fluid resistance, it is known to provide unevenness on the surface of an object, for example. For example, among fluid resistances, riblets are known as a technique for reducing frictional resistance, and dimples are known as a technique for reducing pressure resistance (for example, Patent Document 1). Further, Patent Document 2 discloses a technical idea of arranging a rough surface and a smooth surface to generate a longitudinal vortex at the boundary between the rough surface and the smooth surface to suppress flow separation.

WO2010/29844 JP 2013-57390 A

However, Patent Document 1 and Patent Document 2 do not specifically disclose means for applying a fluid resistance reduction structure to the surface of an object. In addition, Patent Document 2 does not refer to specific shapes and configurations of the rough surface and the smooth surface in detail.

The present disclosure has been made in view of the above circumstances, and a main object thereof is to provide an uneven resin film and a laminated film capable of reducing pressure resistance.

An embodiment of the present disclosure provides an uneven resin film having an uneven structure capable of reducing pressure resistance on its surface.

In the uneven resin film of the present disclosure, in the uneven structure, uneven portions having a plurality of protrusions and recesses and flat portions are alternately arranged in the first direction, and the height of the uneven portions is 20 μm or more and 200 μm. The length of the uneven portion in a second direction orthogonal to the first direction is 30 mm or more, and the width of the uneven portion and the width of the flat portion in the first direction are 0.2 mm or more and 50 mm or less. is preferably

In the above case, it is preferable that the concave-convex portion has a plurality of convex portions and concave portions linearly extending along the first direction. In this case, the width of the linear concave portion is preferably 1 to 12 times the height of the uneven portion. Further, in this case, it is preferable that the width of the linear convex portion is 1 to 2 times the height of the uneven portion.

Further, in the above case, it is preferable that the convex portion of the concave-convex portion protrudes with respect to the surface of the flat portion.

Further, the uneven resin film of the present disclosure may have a resin substrate and a resin layer disposed on one surface of the resin substrate, and may have the uneven structure on the surface of the resin layer. .

Further, the uneven resin film of the present disclosure may have a resin base material and have the uneven structure on the surface of the resin base material.

Another embodiment of the present disclosure provides a laminated film having the uneven resin film described above.

The laminated film of the present disclosure may have an adhesive layer on the surface of the uneven resin film opposite to the uneven structure.

The laminated film of the present disclosure may have a printed layer on the surface of the uneven resin film opposite to the uneven structure.

The present disclosure can provide an uneven resin film and a laminate film capable of reducing pressure resistance.

1A and 1B are a schematic plan view and a cross-sectional view illustrating an uneven resin film of the present disclosure; FIG. 1 is a schematic perspective view illustrating an uneven resin film of the present disclosure; FIG. FIG. 4 is a schematic diagram illustrating gas flow in the uneven resin film of the present disclosure. FIG. 4 is a schematic diagram illustrating gas flow in an uneven resin film. 1 is a schematic cross-sectional view illustrating an uneven resin film of the present disclosure; FIG. 1 is a schematic perspective view illustrating an uneven resin film of the present disclosure; FIG. 1A and 1B are a schematic plan view and a cross-sectional view illustrating an uneven resin film of the present disclosure; FIG. 1A and 1B are a schematic plan view and a cross-sectional view illustrating an uneven resin film of the present disclosure; FIG. FIG. 4 is a schematic cross-sectional view illustrating an uneven portion in the uneven resin film of the present disclosure; 1 is a schematic plan view illustrating an uneven resin film of the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating an uneven resin film of the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating a laminated film of the present disclosure; FIG.

Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be embodied in many different modes and should not be construed as limited to the description of the embodiments exemplified below. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual form, but this is only an example and limits the interpretation of the present disclosure. not something to do. In addition, in this specification and each figure, the same reference numerals may be given to the same elements as those described above with respect to the existing figures, and detailed description thereof may be omitted as appropriate.

In this specification, when expressing a mode of arranging another member on top of a certain member, when simply describing “above” or “below”, unless otherwise specified, 2 includes both cases in which another member is arranged directly above or directly below, and cases in which another member is arranged above or below a certain member via another member. In addition, in this specification, when expressing a mode in which another member is arranged on the surface of a certain member, unless otherwise specified, when simply described as “on the surface”, it means directly above, so as to contact the certain member, unless otherwise specified. Alternatively, it includes both the case of arranging another member directly below and the case of arranging another member above or below a certain member via another member.

Moreover, in this specification, the terms "film" and "sheet" are not to be distinguished from each other based only on the difference of names. For example, "film" also includes sheets.

Hereinafter, the uneven resin film and laminated film of the present disclosure will be described in detail.

A. Concavo-convex Resin Film The concavo-convex resin film of the present disclosure has, on its surface, a concavo-convex structure capable of reducing pressure resistance.

By applying the uneven resin film of the present disclosure to the surface of an object, pressure resistance can be reduced, and as a result, energy saving and carbon dioxide reduction can be realized. The concave-convex resin film of the present disclosure can be applied to the surface of an object by, for example, sticking, and can easily provide a gas resistance reduction structure to the surface of the object. In addition, since the concave-convex resin film of the present disclosure is in the form of a film, it can be applied to a curved surface or a three-dimensional shape. Furthermore, the uneven resin film of the present disclosure can be reattached or replaced.

Each configuration of the uneven resin film of the present disclosure will be described below.

1. Concavo-convex structure The concavo-convex structure in the present disclosure is not particularly limited as long as it is a concavo-convex structure that can reduce pressure resistance and can generate turbulence. Rough and smooth structure in which parts (rough surface) and flat parts (smooth surface) are alternately arranged; dimple structure with multiple recesses; pillar structure with multiple pillars; A random concave-convex structure formed by

The rough-smoothing structure and the dimple structure will be described below.

(1) Rough-Smooth Structure In the rough-smooth structure according to the present disclosure, uneven portions (rough surfaces) having a plurality of protrusions and recesses and flat portions (smooth surfaces) are alternately arranged.

Among them, in the rough and smooth structure, that is, the uneven structure, uneven portions having a plurality of convex portions and concave portions and flat portions are alternately arranged in the first direction, and the height of the uneven portion is 20 μm or more and 200 μm or less. and the length of the uneven portion in a second direction orthogonal to the first direction is 30 mm or more, and the width of the uneven portion and the width of the flat portion in the first direction are 0.2 mm or more and 50 mm or less. is preferred.

1(a) to (c) and FIG. 2 are a schematic plan view, a cross-sectional view and a perspective view showing an example of the uneven resin film of the present disclosure, and FIG. 1(b) is A- of FIG. FIG. 1(c) is a cross-sectional view taken along line BB of FIG. 1(a), and FIG. 2 is a perspective view of FIG. 1(a). As shown in FIGS. 1(a) to 1(c) and FIG. 2, the uneven resin film 1 has an uneven structure 4 on its surface. The portions 2 and flat portions 3 are alternately arranged in the first direction d1. The height H1 of the uneven portion 2 is within a predetermined range, the length L1 of the uneven portion 2 in the second direction d2 perpendicular to the first direction d1 is equal to or greater than a predetermined value, and the uneven portion 2 in the first direction d1 and the width W2 of the flat portion 3 are within a predetermined range.

3(a) and 3(b), the uneven resin film of the present disclosure has an uneven structure in which uneven portions having a plurality of convex portions and concave portions and flat portions are alternately arranged in the first direction on the surface. 3(b) is a cross-sectional view taken along the line AA of FIG. 3(a). FIG. As shown in FIG. 3(a), when the gas F flows along the surface of the uneven resin film 1, as shown in FIG. A secondary flow, a longitudinal vortex LV, is generated near the boundary parallel to . Therefore, separation of the flow from the surface of the uneven resin film 1 can be suppressed.

In the concave-convex structure, the length L1 of the concave-convex portion 2 in the second direction d2 is equal to or greater than a predetermined value. can.

Here, when an object is placed in a gas flow, the resistance acting on the object includes, for example, pressure resistance and frictional resistance, and the pressure resistance is generated by separation of the flow. Pressure resistance is a problem, for example, moving bodies such as automobiles, trains, and aircraft; pipes such as ducts and gas pipes; windmills; /s or more and about 250 m/s or less (about 10 km/h or more and 900 km/h or less).

In the concave-convex structure, for example, when the flow velocity of the gas flowing through the object is within the above range, the height H1 of the concave-convex portion 2 is appropriately adjusted within a predetermined range, so that the gap between the concave-convex portion 2 and the flat portion 3 is reduced. A longitudinal vortex LV can be easily generated in the vicinity of the boundary.

Here, in the flow around the object, a very thin layer on the surface of the object is strongly affected by the viscosity. A layer strongly affected by this viscosity is called a boundary layer.

FIGS. 4(a) to 4(c) show an uneven structure in which uneven portions having a plurality of convex portions and concave portions and flat portions are alternately arranged in the first direction on the surface of the uneven resin film. 3 is a schematic diagram showing the relationship between the width of the uneven portion and the flat portion in the first direction and the longitudinal vortex generated near the boundary between the uneven portion and the flat portion; FIG. For example, as shown in FIG. 4A, when the width W1 of the uneven portion 2 and the width W2 of the flat portion 3 in the first direction are large, a large vertical vortex LV is generated near the boundary between the uneven portion 2 and the flat portion 3. Although generated, the longitudinal vortex LV is less likely to wrap around the central portion of the uneven portion 2 and the central portion of the flat portion 3 . Further, for example, as shown in FIG. 4C, when the width W1 of the uneven portion 2 and the width W2 of the flat portion 3 in the first direction are small, the The longitudinal vortex LV is small, and it is difficult for the longitudinal vortex LV to reach the outer edge of the boundary layer. In these cases, flow separation can be suppressed, but the effect is small. In FIGS. 4(a) to 4(c), δ indicates the boundary layer thickness.

On the other hand, in the uneven structure, the width W1 of the uneven portion 2 and the width W2 of the flat portion 3 in the first direction d1 are within a predetermined range. A large longitudinal vortex LV is generated near the boundary between the portion 2 and the flat portion 3, and the longitudinal vortex LV can be generated in the entire boundary layer.

Therefore, in the uneven structure, uneven portions having a plurality of protrusions and recesses and flat portions are alternately arranged in the first direction, and the length of the uneven portion in the second direction orthogonal to the first direction is The boundary between the uneven portion and the flat portion is equal to or greater than a predetermined value, the height of the uneven portion is within a predetermined range, and the width of the uneven portion and the width of the flat portion in the first direction are within a predetermined range. Longitudinal vortices can be efficiently generated in the vicinity, and flow separation can be effectively suppressed.

The concave-convex portion and the flat portion will be described below.

In the uneven structure according to the present disclosure, it is preferable that uneven portions having a plurality of protrusions and recesses and flat portions are alternately arranged in the first direction.

(a) Concavo-convex portion In the concave-convex structure according to the present disclosure, the length of the concave-convex portion in the second direction is preferably 30 mm or more, and more preferably 50 mm or more, for example. If the length of the concave-convex portion in the second direction is too short, longitudinal vortices are less likely to occur in the vicinity of the boundary between the concave-convex portion and the flat portion, which may reduce the effect of suppressing flow separation. In addition, since the length of the uneven portion in the second direction is 50 mm or more, a longitudinal vortex can be reliably generated in the vicinity of the boundary between the uneven portion and the flat portion. Also, the length of the uneven portion in the second direction is, for example, preferably 1000 mm or less, and more preferably 200 mm or less. If the length of the uneven portion in the second direction is too long, even if the pressure resistance can be reduced, the frictional resistance increases, and the gas resistance may not be sufficiently reduced. may increase.

Here, the length L1 of the uneven portion 2 in the second direction d2 is the distance from one end to the other end of the uneven portion 2 in the second direction d2, as shown in FIG. say. Further, for example, as shown in FIG. 1(c), when the surface of the uneven resin film 1 is flat, the length of the uneven portion in the second direction is, for example, as shown in FIG. 1(a). It refers to the length L1 of the uneven portion 2 on the plane in the two directions d2. For example, as shown in FIG. 5A, when the surface of the uneven resin film 1 is curved, the length of the uneven portion in the second direction is the length of the uneven portion 2 on the curved surface in the second direction d2. It refers to the length L1.

Further, in the uneven structure according to the present disclosure, the height of the uneven portion is preferably, for example, 20 μm or more and 200 μm or less, and more preferably 50 μm or more and 200 μm or less. As described above, for example, moving objects such as automobiles, trains, and aircraft; pipes such as ducts and gas pipes; windmills; (approximately 10 km / h or more and 900 km / h or less), and when the flow velocity is within the above range, the height of the uneven part is appropriately adjusted within the above range, so that the vicinity of the boundary between the uneven part and the flat part It is possible to make it easier to generate longitudinal vortices in. Further, for example, the speed of an automobile is approximately 10 km/h or more and 120 km/h or less, and in this case, the flow velocity of the air flowing through the automobile is approximately 3 m/s or more and 33 m/s or less (approximately 10 km/h or more and 120 km/h or less). When the flow velocity is within the above range, longitudinal vortices can be easily generated in the vicinity of the boundary between the uneven portion and the flat portion by appropriately adjusting the height of the uneven portion within the range of 50 μm or more and 200 μm or less. can be done.

More preferably, the height of the uneven portion is about 1/10 or more and 1/100 or less of the thickness of the boundary layer. Further, the faster the gas flow, the thinner the thickness of the boundary layer. Therefore, the higher the gas flow, the lower the height of the irregularities within the above range.

Here, the height H1 of the uneven portion 2 refers to the distance from the bottom portion of the concave portion 12 to the top portion of the convex portion 11 of the uneven portion 2, as shown in FIG. 1(c), for example.

Further, in the concave-convex structure of the present disclosure, the width of the concave-convex portion in the first direction is, for example, 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 uneven portion in the first direction is within the above range, a large longitudinal vortex LV is generated near the boundary between the uneven portion 2 and the flat portion 3, as shown in FIG. can generate a longitudinal vortex LV.

More preferably, the width of the uneven portion in the first direction is the same as the boundary layer thickness. Further, the faster the gas flow rate, the thinner the thickness of the boundary layer. Therefore, it is preferable that the faster the gas flow rate, the smaller the width of the uneven portion in the first direction within the above range.

The width of the uneven portion in the first direction may be the same as or different from the width of the flat portion in the first direction, which will be described later, as long as it is within the above range. Above all, it is preferable that the width of the uneven portion in the first direction and the width of the flat portion in the first direction are the same. In this case, longitudinal vortices can be generated more efficiently in the vicinity of the boundary between the uneven portion and the flat portion.

Here, the width W1 of the uneven portion 2 in the first direction d1 is, for example, from one end of the uneven portion 2 in the first direction d1 to the other end as shown in FIGS. is the distance between Further, for example, as shown in FIG. 1B, when the surface of the uneven resin film 1 is flat, the width of the uneven portion in the first direction is the width of the uneven portion 2 on the plane in the first direction d1. Refers to W1. For example, as shown in FIG. 5B, when the surface of the uneven resin film 1 is curved, the width of the uneven portion in the first direction is the width of the uneven portion 2 on the curved surface in the first direction d1. Refers to W1.

The uneven portion has a plurality of protrusions and recesses. In the concave-convex portion, it is sufficient that a plurality of convex portions and concave portions are arranged so as to be uniformly distributed. The pattern shape of the protrusions and recesses in plan view may be, for example, a regular pattern or a random pattern. In the case of regular patterns, for example, patterns such as lines, dots, and lattices can be used.

Line-shaped patterns include, for example, straight lines; wavy lines such as sinusoidal waves and triangular waves; and the like. Among them, the linear pattern is preferably a linear pattern.

In addition, in the dot-shaped pattern, examples of the dot arrangement include a square lattice arrangement, a rectangular lattice arrangement, a triangular lattice arrangement, a hexagonal lattice arrangement, a rhombic lattice arrangement, and a parallelogram lattice arrangement. Above all, when the pattern shape of the projections or recesses in a plan view is dot-shaped, the dot arrangement is preferably a triangular lattice arrangement or a rhombic lattice arrangement. In the case of such an arrangement of dots, longitudinal vortices can be easily generated in the vicinity of the boundary between the uneven portion and the flat portion.

Examples of the lattice pattern include square lattice, rectangular lattice, triangular lattice, hexagonal lattice, rhombus lattice, and parallelogram lattice.

For example, FIGS. 2 and 6 show examples in which the pattern shape of the projections 11 and the recesses 12 in plan view is linear, and FIGS. 8(a) and 8(b) are examples in which the pattern shape of the recesses 12 in plan view is dot-shaped and in a triangular lattice arrangement. 7B and 7C are cross-sectional views taken along line AA in FIG. 7A, and FIG. 8B is a cross-sectional view along line AA in FIG. 8A.

When the pattern shape of the projections and recesses in plan view is linear, the longitudinal direction of the linear pattern of the projections and recesses preferably intersects the second direction perpendicular to the first direction. , is substantially perpendicular to the second direction, ie substantially parallel to the first direction. Specifically, when the pattern shape of the projections and recesses is linear, the longitudinal direction of the linear patterns of the projections and recesses should intersect the second direction orthogonal to the first direction. is preferably substantially perpendicular to the second direction, eg substantially parallel to the first direction, as shown in FIGS. 2 and 6, for example. That is, it is preferable that the concave-convex portion has a plurality of convex portions and concave portions linearly extending along the first direction. As will be described later, the uneven resin film is arranged so that the boundary line between the uneven portion 2 and the flat portion 3 is substantially parallel to the flow direction d3 of the gas F, as shown in FIG. It is preferably used as That is, as shown for example in FIG. It is preferable that they are arranged and used such that the second direction d2 is substantially parallel. Therefore, when the longitudinal direction of the linear pattern of protrusions and recesses intersects the second direction orthogonal to the first direction, the longitudinal direction of the linear pattern of protrusions and recesses is It can be crossed with respect to the gas flow direction. In such a case, longitudinal vortices can be easily generated in the vicinity of the boundary between the uneven portion and the flat portion. Further, when the longitudinal direction of the line-shaped pattern of protrusions and recesses is substantially perpendicular to the second direction orthogonal to the first direction, the longitudinal direction of the line-shaped pattern of protrusions and recesses is It can be substantially perpendicular to the gas flow direction. In such a case, it is possible to further facilitate the generation of longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion.

Further, when the longitudinal direction of the line-shaped pattern of the protrusions and recesses intersects the second direction, the angle formed by the longitudinal direction of the line-shaped pattern and the second direction is, for example, 90°± 45° is preferred. Similarly, when the longitudinal direction of the linear pattern of the protrusions and recesses intersects the second direction, the angle formed by the longitudinal direction of the linear pattern and the second direction is, for example, 90°. ±45° is preferred.

That is, when the longitudinal direction of the line-shaped pattern of protrusions and recesses intersects the gas flow direction, the angle formed by the longitudinal direction of the line-shaped pattern and the gas flow direction is, for example, 90°. °±45° is preferred. Similarly, when the longitudinal direction of the linear pattern of the protrusions and recesses intersects the gas flow direction, the angle formed by the longitudinal direction of the linear pattern and the gas flow direction is, for example, 90°±45° is preferred.

Here, when the longitudinal direction of the line-shaped pattern of the protrusions and recesses is substantially parallel to the first direction, it means that the angle between the longitudinal direction of the line-shaped pattern and the first direction is 0°± 5°. Similarly, when the longitudinal direction of the linear pattern of the protrusions and recesses is substantially parallel to the first direction, it means that the angle formed by the longitudinal direction of the linear pattern and the first direction is 0°± 5°.

Further, when the longitudinal direction of the line-shaped pattern of the protrusions and recesses is substantially perpendicular to the gas flow direction, it means that the angle formed by the longitudinal direction of the line-shaped pattern and the gas flow direction is 90°. ±5°. Similarly, when the longitudinal direction of the linear pattern of the protrusions and recesses is substantially perpendicular to the direction of gas flow, it means that the angle formed by the longitudinal direction of the linear pattern and the direction of gas flow is 90°. °±5°.

Note that the longitudinal direction of a linear pattern is, for example, the direction in which the linear pattern extends in the case of a linear pattern, and the direction in which the wavy pattern extends in the case of a wavy pattern.

Moreover, in the uneven portion, the protrusion may protrude with respect to the surface of the flat portion, or the recess may be recessed with respect to the surface of the flat portion. For example, FIGS. 2 and 7B are examples in which the convex portion 11 of the uneven portion 2 protrudes from the surface of the flat portion 3, and FIGS. This is an example in which the recessed portion 12 of the portion 2 is recessed with respect to the surface of the flat portion 3 .

Among them, it is preferable that the convex portion protrudes from the surface of the flat portion. In such a case, longitudinal vortices can be easily generated in the vicinity of the boundary between the uneven portion and the flat portion.

Therefore, for example, as shown in FIG. 2, the uneven portion 2 has a plurality of convex portions 11 and concave portions 12 linearly extending along the first direction d1, and the convex portion 11 is Protruding is particularly preferred. In such a case, longitudinal vortices can be efficiently generated near the boundary between the uneven portion and the flat portion.

Moreover, the cross-sectional shape of the protrusions and recesses is not particularly limited, and examples thereof include a rectangular shape, a trapezoidal shape, a triangular shape, a semicircular shape, and a semielliptical shape. For example, FIG. 9A shows an example in which the cross-sectional shape of the projections 11 and the recesses 12 is rectangular, and FIG. 9B shows an example in which the cross-sections of the projections 11 and the recesses 12 are trapezoidal. 9(c) to (e) are examples in which the cross-sectional shape of the convex portion 11 is triangular, and FIG. 9(f) is an example in which the cross-sectional shape of the convex portion 11 is semi-elliptical. 9g) to (h) are examples in which the cross-sectional shape of the recess 12 is triangular, and FIG. 9(i) is an example in which the cross-sectional shape of the recess 12 is semicircular.

Among them, the cross-sectional shape of the protrusions or recesses is preferably trapezoidal, semicircular, or semielliptical. In the case of these shapes, it is easy to form the uneven portion, and the durability of the uneven portion can be enhanced.

When the pattern shape of the projections and recesses in plan view is linear, the width of the linear projections is preferably, for example, 1 to 2 times the height of the projections and recesses. Specifically, when the pattern shape of the projections and recesses is linear, the width of the linear projections is preferably 1 to 2 times the height of the projections and recesses. If the width of the line-shaped protrusions is too small, it may be difficult to form the protrusions and recesses. Moreover, if the width of the line-shaped convex portion is too large, it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion.

Here, the width of the line-shaped convex portion is the width W3 of the convex portion 11 as shown in FIGS.

Further, when the pattern shape of the projections and recesses in plan view is linear, the width of the linear recesses is, for example, preferably 1 to 12 times the height of the projections and recesses. It is more preferably 4 times or more and 10 times or less. Specifically, when the pattern shape of the projections and recesses in plan view is linear, the width of the linear recesses is preferably 1 to 12 times the height of the projections and recesses. , more preferably 4 times or more and 10 times or less. If the width of the line-shaped concave portion is too small, the density of the convex portions becomes high, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the concave-convex portion and the flat portion. Also, if the width of the line-shaped concave portion is too large, the density of the convex portion will be low, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the concave-convex portion and the flat portion. In addition, when the width of the line-shaped concave portion is 4 to 10 times the height of the uneven portion, longitudinal vortices are generated near the boundary between the uneven portion and the flat portion, effectively suppressing flow separation. can do.

Here, the width of the linear concave portion is the width W4 of the concave portion 12, for example, as shown in FIGS. For example, in FIGS. 9(d), (g) to (i), the width of the recess 12 is zero.

Further, when the pattern shape of the projections and recesses in plan view is linear, the pitch of the linear projections is preferably, for example, 2 times or more and 14 times or less the height of the projections and recesses. , more preferably 5 times or more and 12 times or less. Specifically, when the pattern shape of the projections and recesses in plan view is linear, the pitch of the linear projections is 2 times or more and 14 times or less the height of the projections and recesses. It is preferably 5 times or more and 12 times or less, more preferably. If the pitch of the line-shaped protrusions is too small, the density of the protrusions increases, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion. In addition, if the pitch of the line-shaped protrusions is too large, the density of the protrusions becomes low, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion.

Here, the pitch of the linear protrusions is, for example, the pitch P1 of the protrusions 11 shown in FIGS. 9A to 9I, and refers to the distance between adjacent protrusions 11.

Further, when the pattern shape of the projections in plan view is dot-shaped, the size of the dot-shaped projections in plan view is, for example, 1 to 2 times the height of the uneven portion. is preferred. If the size of the dot-shaped protrusions is too small, it may become difficult to form the protrusions and recesses. Moreover, if the size of the dot-shaped convex portion is too large, it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion.

Further, when the pattern shape of the recesses in plan view is dot-shaped, the size of the dot-shaped recesses in plan view is preferably, for example, 1 to 12 times the height of the uneven part. , more preferably 4 times or more and 10 times or less. If the size of the dot-shaped concave portions is too small, the density of the convex portions increases, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion. Also, if the size of the dot-shaped concave portions is too large, the density of the convex portions will be low, and it may be difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the concave-convex portion and the flat portion. In addition, when the size of the dot-shaped recesses is 4 times or more and 10 times or less than the height of the uneven part, a vertical vortex is generated near the boundary between the uneven part and the flat part to effectively separate the flow. can be suppressed.

Here, the size of the dot-shaped protrusions or recesses in plan view refers to, for example, the diameter when the plan view shape of the protrusions or recesses is circular, and the plan view shape of the protrusions or recesses is elliptical. In the case of a shape, it refers to the major axis, and in the case that the projection or recess has a rectangular shape in plan view, it refers to the length of the diagonal line.

Further, when the pattern shape of the projections or recesses in plan view is dot-shaped, the pitch of the tod-shaped projections or recesses is, for example, 2 times or more and 14 times or less the height of the projections and recesses. is preferable, and 5 times or more and 12 times or less is more preferable. If the pitch of the dot-shaped protrusions or recesses is too small, the density of the protrusions increases, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the protrusions and recesses and the flat portion. Also, if the pitch of the dot-shaped protrusions or recesses is too large, the density of the protrusions will be low, and it may be difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the protrusions and recesses and the flat portion.

Here, the pitch of dot-shaped protrusions or recesses refers to the distance between adjacent protrusions or recesses.

Further, when the pattern shape of the projections in plan view is a lattice shape, the width of the lattice-shaped projections is preferably, for example, 1 to 2 times the height of the irregularities. If the width of the grid-shaped protrusions is too small, it may be difficult to form the uneven portions. Moreover, if the width of the grid-shaped convex portion is too large, it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion.

Further, when the pattern shape of the projections in a plan view is a lattice shape, the interval between the lattice-shaped projections is preferably, for example, 1 to 12 times the height of the irregularities. It is more preferable to be 10 times or less. If the intervals between the grid-like projections are too small, the density of the projections increases, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion. Moreover, if the intervals between the lattice-shaped convex portions are too large, the density of the convex portions will be low, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion. In addition, when the interval between the lattice-shaped projections is 4 to 10 times the height of the irregularities, a longitudinal vortex is generated near the boundary between the irregularities and the flat part, effectively separating the flow. can be suppressed.

Further, when the pattern shape of the concave portion in plan view is a lattice shape, the width of the concave portion in the lattice shape is, for example, preferably 1 to 12 times, and 4 times or more, the height of the uneven portion. It is more preferably 10 times or less. If the width of the grid-shaped concave portions is too small, the density of the convex portions increases, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the concave-convex portion and the flat portion. Also, if the width of the grid-like concave portions is too large, the density of the convex portions becomes low, which may make it difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion. In addition, when the width of the grid-shaped concave portion is 4 to 10 times the height of the uneven portion, longitudinal vortices are generated near the boundary between the uneven portion and the flat portion, effectively suppressing flow separation. can do.

Further, when the pattern shape of the concave portions in a plan view is a lattice shape, the interval between the concave portions in the lattice shape is preferably, for example, 1 to 2 times the height of the concave and convex portions. If the intervals between the grid-like concave portions are too small, it may become difficult to form the uneven portions. Moreover, if the intervals between the grid-like concave portions are too large, it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion.

Further, when the pattern shape of the projections or recesses in plan view is a lattice shape, the pitch of the lattice-shaped projections or recesses is, for example, 2 times or more and 14 times or less the height of the projections and recesses. is preferable, and 5 times or more and 12 times or less is more preferable. If the pitch of the grid-shaped protrusions or recesses is too small, the density of the protrusions increases, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the protrusions and recesses and the flat portion. Also, if the pitch of the grid-like projections or recesses is too large, the density of the projections will be low, and it may be difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the projections and depressions and the flat portion.

The dimensions of the irregularities, recesses, and projections are measured by observing the surface or thickness direction cross-section of the irregular resin film with a laser microscope, a stylus surface profiler, or a scanning electron microscope (SEM). can be done.

The shape of the uneven portion in plan view is not particularly limited as long as it is a shape that can generate a vertical vortex near the boundary between the uneven portion and the flat portion, and examples thereof include a rectangular shape and an arc shape. . For example, FIG. 1A shows an example in which the uneven portion 2 has a rectangular shape in plan view, and FIG. 10 shows an example in which the uneven portion 2 has a rectangular shape and an arc shape in plan view. Above all, it is preferable that the shape of the concave-convex portion in a plan view is a rectangular shape.

In the concave-convex structure, it is preferable that the concave-convex portions and the flat portions are alternately arranged in the first direction. In this case, the uneven portions and the flat portions may be alternately arranged in the first direction. For example, the uneven portions and the flat portions may be alternately arranged in parallel in the first direction. They may be alternately arranged non-parallel. For example, FIG. 1A shows an example in which uneven portions 2 and flat portions 3 are alternately arranged in parallel in the first direction d1, and FIG. is arranged non-parallel to . For example, when applying an uneven resin film to a three-dimensional curved surface of an object, uneven portions and flat portions may be alternately arranged non-parallel in the first direction. Among them, it is preferable that the uneven portions and the flat portions are alternately arranged in parallel in the first direction.

(b) Flat portion In the uneven structure according to the present disclosure, the width of the flat portion in the first direction 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 flat portion in the first direction is within the above range, a large vertical vortex LV is generated near the boundary between the uneven portion 2 and the flat portion 3, as shown in FIG. can generate a longitudinal vortex LV.

More preferably, the width of the plateau in the first direction is the same as the boundary layer thickness. Further, the faster the gas flow rate, the thinner the thickness of the boundary layer. Therefore, it is preferable that the faster the gas flow rate, the smaller the width of the flat portion in the first direction within the above range.

Here, the width W2 of the flat portion 3 in the first direction d1 is the width W2 in the first direction d1 in the flat portion 3 positioned between adjacent uneven portions 2 as shown in FIGS. The distance from one end of the flat portion 3 to the other end. Further, for example, as shown in FIG. 1B, when the surface of the uneven resin film 1 is flat, the width of the flat portion in the first direction is the width of the flat portion 3 on the plane in the first direction d1. Refers to W2. Further, for example, as shown in FIG. 5B, when the surface of the uneven resin film 1 is curved, the width of the flat portion in the first direction is the width of the flat portion 3 on the curved surface in the first direction d1. Refers to W2.

(2) Dimple structure The dimple structure has a plurality of recesses.

In the dimple structure, it is sufficient that the plurality of recesses are arranged so as to be uniformly distributed. The pattern shape of the recesses in plan view may be, for example, a regular pattern or a random pattern.

Examples of the arrangement of the concave portions include a square lattice arrangement, a rectangular lattice arrangement, a triangular lattice arrangement, a hexagonal lattice arrangement, a rhombus lattice arrangement, and a parallelogram lattice arrangement.

The shape of the recess in plan view is not particularly limited, and examples thereof include a circular shape and an elliptical shape. Moreover, the planar view shape of a recessed part may be irregular.

The cross-sectional shape of the recess is not particularly limited, and examples thereof include a semicircular shape, a semielliptical shape, and a trapezoidal shape.

The depth of the recess is appropriately set so as to have a dimple structure capable of reducing pressure resistance. Specifically, the depth of the recess is preferably 0.10 mm or more and 10.0 mm or less, more preferably 0.13 mm or more and 8.0 mm or less, and 0.15 mm or more and 5.0 mm or less. is more preferred. If the depth of the concave portion is too small, the volume of the concave portion becomes small, which may result in insufficient vortex (turbulent flow) generation. Also, if the depth of the concave portion is too large, it may become difficult to form a film.

The size of the concave portion in a plan view is appropriately set so as to have a dimple structure capable of reducing pressure resistance. Specifically, the radius of curvature of the recess is preferably 1.25 mm or more and 100 mm or less, more preferably 1.50 mm or more and 10 mm or less, and even more preferably 1.75 mm or more and 5 mm or less. If the radius of curvature of the concave portion is too small, the volume of the concave portion becomes small, which may result in insufficient vortex (turbulent flow) generation. Also, if the radius of curvature of the concave portion is too large, it may become difficult to form a film.

The dimensions of the concave portions can be measured by observing the surface or thickness direction cross-section of the uneven resin film with a laser microscope, a stylus surface profiler, or a scanning electron microscope (SEM).

2. Structure of Concavo-convex Resin Film The concavo-convex resin film in the present disclosure can have at least a resin base material. The resin film in the present disclosure only needs to have the uneven structure on the surface. For example, the uneven structure may be configured integrally with the resin base material, or may be configured separately from the resin base material. may have been That is, the uneven resin film of the present disclosure may have a resin substrate and have the uneven structure on the surface of the resin substrate, or alternatively, the resin substrate and one surface of the resin substrate and the surface of the resin layer may have the uneven structure.

In addition, the uneven resin film in the present disclosure has, as the uneven structure, for example, a rough and smooth structure in which uneven portions (rough surfaces) having a plurality of protrusions and recesses and flat portions (smooth surfaces) are alternately arranged. In this case, for example, as shown in FIGS. The uneven portion 2 may be configured separately from the resin base material 10 . Further, when the concave-convex portion is formed separately from the resin base material, for example, as shown in FIGS. It may be the surface of the base material 10, and as shown in FIGS. and a flat portion 3.

The uneven structure may be transparent or opaque.

A resin can be used as the material of the uneven structure. When the concave-convex structure is formed integrally with the resin base material, the same material as the resin base material described below can be used as the material of the concave-convex structure. Further, when the uneven structure is formed separately from the resin substrate, the material for the uneven structure may be, for example, an ionizing radiation-curable resin composition such as an ultraviolet-curable resin composition or an electron beam-curable resin composition. or a cured product of a curable resin composition such as a thermosetting resin composition; a thermoplastic resin; and the like.

In addition, the uneven structure contains additives such as ultraviolet absorbers, antioxidants, plasticizers, stabilizers, lubricants, fillers, coloring agents, processing aids, antistatic agents, and anti-twisting agents as necessary. You may Weather resistance can be improved when the uneven structure contains an ultraviolet absorber.

The method of forming the uneven structure may be, for example, a method of forming an uneven structure on a resin substrate, or a method of forming an uneven shape on one surface of the resin substrate.

As a method for forming an uneven structure on a resin substrate, for example, a curable resin composition is used, and the curable resin composition is applied in a predetermined pattern on the resin substrate and cured; Using a resin composition, apply an ultraviolet curable resin composition on a resin substrate, press a mold against the coating film, irradiate ultraviolet rays to cure the ultraviolet curable resin composition, and then remove from the mold. Peeling, so-called photopolymer method (2P method); using an ionizing radiation-curable resin composition, coating the ionizing radiation-curable resin composition on a resin substrate, and applying ionizing radiation such as ultraviolet rays and electron beams in a pattern. A so-called lithographic method of irradiating and developing; a method of forming a resin layer on a resin substrate and embossing the surface of the resin layer; and the like. Alternatively, a resin layer having an embossed surface may be prepared separately, and the resin layer may be laminated on the resin substrate.

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

In the case of the embossing method, the material of the resin layer is not particularly limited as long as it can be embossed, and a thermoplastic resin 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 according to the use of the uneven resin film. For example, when the uneven resin film of the present disclosure is used as a wrapping film or marking film for moving bodies such as automobiles, trains, and aircraft, the thickness of the resin layer can be about 30 μm or more and 300 μm or less.

Moreover, as a method of shaping uneven|corrugated shape in one side of a resin base material, the method of embossing the single side|surface or both surfaces of a resin base material, etc. are mentioned, for example.

When the resin base material is integrally formed with the concave-convex structure, for example, a thermoplastic resin can be used as the material of the resin base material, and it can be used by appropriately selecting from general-purpose plastics and engineering plastics. . Among them, vinyl chloride resin is preferable from the viewpoint of weather resistance and abrasion resistance.

In addition, if necessary, the resin base material may contain additives such as plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, ultraviolet absorbers, antioxidants, antistatic agents, and anti-twisting agents. may contain. When the resin base material is integrally formed with the concave-convex structure and the resin base material contains an ultraviolet absorber, the weather resistance can be enhanced.

The resin substrate may be transparent or opaque.

The thickness of the resin substrate is not particularly limited, and is appropriately selected according to the use of the uneven resin film. For example, when the uneven resin film of the present disclosure is used as a wrapping film or marking film for moving bodies such as automobiles, trains, and aircraft, the thickness of the resin substrate can be about 80 μm or more and 350 μm or less.

3. Size and shape of uneven resin film The size of the uneven resin film of the present disclosure in plan view is not particularly limited as long as the uneven resin film can have an uneven structure capable of reducing pressure resistance on the surface. It is selected as appropriate according to the application and the like. The uneven resin film of the present disclosure may be arranged on the entire surface of the object, or may be arranged on a part of the surface of the object.

In addition, the shape of the uneven resin film of the present disclosure in plan view is not particularly limited as long as it can be an uneven resin film having an uneven structure capable of reducing pressure resistance on the surface, depending on the application and the like. Selected as appropriate. The shape of the uneven resin film of the present disclosure in plan view may be, for example, a simple geometric shape such as a rectangular shape, a circular shape, an elliptical shape, a polygonal shape, or a complicated shape.

In addition, the thickness of the entire uneven resin film of the present disclosure is not particularly limited, and is appropriately selected according to the application of the uneven resin film, and can be, for example, 35 μm or more and 350 μm or less.

4. Applications When the uneven resin film of the present disclosure has, as the uneven structure, for example, a rough and smooth structure in which uneven portions (rough surface) having a plurality of protrusions and recesses and flat portions (smooth surface) are alternately arranged, The uneven resin film may be arranged and used so that the angle formed by the boundary line between the uneven portion (rough surface) and the flat portion (smooth surface) and the gas flow direction is, for example, 0°±15°. preferable. That is, when the uneven resin film of the present disclosure has an uneven structure, for example, an uneven structure in which uneven portions having a plurality of convex portions and concave portions and flat portions are alternately arranged in the first direction, the uneven structure The resin film is preferably arranged and used so that the angle formed by the first direction and the gas flow direction is, for example, 90°±15°.

Among them, in the above case, the uneven resin film is arranged so that the boundary line between the uneven portion 2 and the flat portion 3 is substantially parallel to the flow direction d3 of the gas F, as shown in FIG. It is more preferable to be used as That is, in the above case, for example, as shown in FIG. It is more preferable to be arranged and used so that the second direction d2 orthogonal to . As a result, longitudinal vortices can be easily generated in the vicinity of the boundary between the uneven portion and the flat portion, and flow separation can be suppressed.

Here, when the boundary line between the uneven portion and the flat portion is substantially parallel to the flow direction of the gas, it means that the angle between the boundary line between the uneven portion and the flat portion and the flow direction of the gas is 0°±5. °. The first direction being substantially perpendicular to the gas flow direction means that the angle formed by the first direction and the gas flow direction is 90°±5°.

Further, when the uneven resin film of the present disclosure has, for example, a dimple structure as the uneven structure, the uneven resin film can be arbitrarily arranged with respect to the gas flow direction.

The uneven resin film of the present disclosure can be applied to the surface of an object. Specifically, the uneven resin film of the present disclosure can be used in automobiles such as passenger cars, trucks, and buses; railway vehicles such as trains, bullet trains, and locomotives; aircraft such as airplanes, helicopters, and drones; It can be applied to the housing of a moving body or the surface of a part. In addition, the uneven resin film of the present disclosure can also be applied to, for example, the inner surface of pipes such as ducts and gas pipes; the surface of windmill blades; the surface of outlets and louvers of air conditioning equipment such as air conditioners; Among them, the uneven resin film of the present disclosure is preferably applied to the surface of the housing or parts of a moving body, and is applied to the surface of a moving body that is a non-streamline object, specifically a bluff body. preferably. This is because, in a bluff body, the contribution of pressure resistance is large among gas resistances, and the effects of the present disclosure are exhibited remarkably. A mobile body that is a bluff body includes, for example, preferably a truck, a bus, and the like. More specifically, the uneven resin film of the present disclosure can be used as a wrapping film or a marking film for moving bodies.

Further, when the uneven resin film of the present disclosure is applied to the surface of an object, the surface of the object may be flat or curved.

In addition, the uneven resin film of the present disclosure can reduce pressure resistance among gas resistances, but the gas is not particularly limited. The gas density is preferably, for example, 0.08 kg/m ³ or more and 10 kg/m ³ or less. Among them, the gas is preferably air.

B. Laminated Film The laminated film in the present disclosure has the uneven resin film described above.

Since the laminated film in the present disclosure has the uneven resin film described above, by applying it to the surface of an object, pressure resistance can be reduced, and as a result, energy saving and carbon dioxide reduction can be realized. In addition, the laminated film in the present disclosure can be applied to the surface of an object by, for example, sticking, and can easily provide a gas resistance reduction structure to the surface of the object. Moreover, since the laminated film in the present disclosure is film-like, it can be applied to a curved surface or a three-dimensional shape. Furthermore, the laminated film in the present disclosure can be reattached or replaced.

Each configuration of the laminated film in the present disclosure will be described below.

1. Concave-convex resin film The concavo-convex resin film in the present disclosure has been described in detail in the section “A. Concave-convex resin film” above, so description thereof will be omitted here.

2. Other Configurations The laminated film in the present disclosure may further have other configurations in addition to the uneven resin film.

(1) Adhesive Layer The laminated film 20 in the present disclosure may have an adhesive layer 21 on the surface opposite to the uneven structure of the uneven resin film 1, as shown in FIG. 12(a), for example. The adhesive layer is a layer for attaching the uneven resin film to the surface of an object. By arranging the adhesive layer on one side of the uneven resin film, the uneven resin film can be easily attached to the surface of the object.

The adhesive used in the adhesive layer is appropriately selected according to the application of the laminated film, and examples thereof include acrylic adhesives, urethane adhesives, silicone adhesives, rubber adhesives, vinyl ether adhesives, and the like. mentioned.

In addition, the adhesive layer may or may not have removability, but it is preferable that it has removability. When the adhesive layer has releasability, it can be reapplied when the laminated film is applied to the surface of the object, and when the laminated film is reapplied or removed, the object can be removed without leaving adhesive residue. It is possible to peel the laminated film from.

The term "removability" refers to the property of being able to peel off easily without destroying the object and leaving no adhesive on the surface of the object after the laminated film has been applied to the surface of the object.

Moreover, the adhesive layer may contain a coloring agent. By including a colorant in the adhesive layer, shielding properties can be imparted. For example, when a design is applied to the surface of an article, the adhesive layer contains a coloring agent, and the laminated film further has a printed layer as described later, the laminated film can be attached to the surface of the article. Then, the design can be hidden and a new design can be applied.

The thickness of the adhesive layer is not particularly limited, and is appropriately selected according to the use of the laminated film. For example, when the laminated film of the present disclosure is used as a wrapping film or marking film for moving bodies such as automobiles, trains, and aircraft, the thickness of the adhesive layer can be about 5 μm or more and 50 μm or less. If the thickness of the adhesive layer is too thin, the adhesion to objects may be insufficient.

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

Further, a separator may be arranged on the surface of the adhesive layer opposite to the uneven resin film.

(2) Printed layer The laminated film in the present disclosure may have a printed layer on the surface opposite to the uneven structure of the uneven resin film. Designability can be imparted by having the printed layer on the laminated film.

The printed layer can display information such as letters, numbers, symbols, pictures, patterns, and marks.

In addition, 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 uneven resin film, or, for example, as shown in FIG. The printed layer 23 may be formed by printing on the layer 22 . The printed layer may be arranged in a pattern on the resin base material or the support layer, or may be arranged over the entire surface of the resin base material or the support layer. Also, 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.

Moreover, the support layer may contain a coloring agent. By containing a coloring agent in the support layer, shielding properties can be imparted. For example, when a design is applied to the surface of an article, if the laminated film has a printed layer and the support layer contains a colorant, the laminated film can be attached to the surface of the article to achieve the design. can be hidden and a new design can be applied.

The thickness of the support layer is not particularly limited, and is appropriately selected according to the use of the laminated film.

Further, when forming the printed layer by printing on the support layer, for example, as shown in FIG. A printed sheet having the may be formed.

(3) Protective layer The laminated film in the present disclosure may have a protective layer on the uneven structure side of the uneven resin film. The protective layer can protect the concavo-convex structure and improve the abrasion resistance.

When a protective layer is arranged on the uneven structure side of the uneven resin film, it is preferable that the dimensions of the unevenness on the protective layer side of the laminated film satisfy the above-described dimensions of the uneven structure of the uneven resin film. .

For example, a resin can be used as the material of the protective layer. Among them, electron beam curable resins and fluororesins are preferable from the viewpoint of weather resistance and abrasion resistance.

In addition, the protective layer contains additives such as ultraviolet absorbers, antioxidants, plasticizers, stabilizers, lubricants, fillers, coloring agents, processing aids, antistatic agents, and flame retardants, as necessary. You may Weather resistance can be enhanced when the protective layer contains an ultraviolet absorber.

The thickness of the protective layer is preferably, for example, 0.01 μm or more and 10 μm or less.

3. Size and Shape of Laminated Film The planar view size of the laminated film in the present disclosure is appropriately selected according to the application and the like. The laminated film in the present disclosure may be placed on the entire surface of the object, or may be placed on part of the surface of the object.

In addition, the shape of the laminated film in plan view in the present disclosure is appropriately selected depending on the application, and can be, for example, the same as the shape of the uneven resin film in plan view.

4. Applications In the present disclosure, the arrangement of the laminated film in the gas flow direction is appropriately set according to the type of uneven structure of the uneven resin film, and may be the same as the arrangement of the uneven resin film in the gas flow direction. can.

The use of the laminated film in the present disclosure can be the same as the use of the uneven resin film described above.

Note that the present disclosure is not limited to the above embodiments. The above embodiment is an example, and any device that has substantially the same configuration as the technical idea described in the claims of the present disclosure and achieves the same effect is the present invention. It is included in the technical scope of the disclosure.

Examples and comparative examples are given below to further illustrate the present disclosure.

[Examples 1 to 11]
First, using a printing material ("MPI1105" manufactured by Avery Dennison) having a vinyl chloride resin film, an adhesive layer and a release paper in this order, a pattern is printed on the vinyl chloride resin film of the printing material to form a printing layer. formed. Next, using a laminate film ("DOL1460" manufactured by Avery Dennison) having a vinyl chloride resin film, an adhesive layer, and a release paper in this order, after peeling the release paper from the laminate film, the laminate film is laminated on the printed layer. did. Next, on the vinyl chloride resin film of the laminate film, a UV inkjet device was used to eject and cure a UV curable ink to form an uneven portion having a plurality of linear convex portions and concave portions. Moreover, as shown in FIG. 1A, the uneven portions were formed so that the uneven portions and the flat portions were alternately arranged in stripes. The dimensions of the uneven portion and the flat portion were as shown in Table 1. Thus, a wrapping film was produced.

[evaluation]
The wrapping films of Examples 1 to 11 are pasted on a track-shaped model (length 1250 mm, width 260 mm, height 387 mm), a wind tunnel experiment is performed, and the air resistance coefficient (Cd value) is measured at a wind speed of 25 m / s. did. Moreover, the case where the wrapping film was not attached was used as a comparative example.

It was confirmed that in Examples 1 to 11, the Cd value was smaller than in the comparative example, and the gas resistance was reduced. Among them, in Examples 1 to 7, the height of the uneven portion, the length of the uneven portion in the second direction, the width of the uneven portion in the first direction, and the width of the flat portion are all within predetermined ranges. Compared with Examples 8 to 11, the gas resistance reduction effect was large.

REFERENCE SIGNS LIST 1 ... uneven resin film 2 ... uneven portion 3 ... flat portion 4 ... uneven structure 10 ... resin substrate 11 ... convex portion 12 ... concave portion 20 ... laminated film 21 ... adhesive layer 23 ... printing layer d1 ... first direction d2 ... second Direction H1 ... Height of the uneven portion L1 ... Length of the uneven portion in the second direction W1 ... Width of the uneven portion in the first direction W2 ... Width of the flat portion in the first direction

Claims (11)

An uneven resin film having an uneven structure capable of reducing pressure resistance on its surface. In the concave-convex structure, concave-convex portions having a plurality of convex portions and concave portions and flat portions are alternately arranged in the first direction,
The height of the uneven portion is 20 μm or more and 200 μm or less,
The length of the uneven portion in a second direction orthogonal to the first direction is 30 mm or more,
The uneven resin film according to claim 1, wherein the width of the uneven portion and the width of the flat portion in the first direction are 0.2 mm or more and 50 mm or less. 3. The uneven resin film according to claim 2, wherein said uneven portion has a plurality of said convex portions and said concave portions linearly extending along said first direction. The concave-convex resin film according to claim 3, wherein the width of the linear concave portion is 1 to 12 times the height of the concave-convex portion. 5. The uneven resin film according to claim 3 or 4, wherein the width of the linear protrusions is 1 to 2 times the height of the uneven portions. The uneven resin film according to any one of claims 2 to 5, wherein the convex portion of the uneven portion protrudes with respect to the surface of the flat portion. Claims 1 to 6, wherein the uneven resin film has a resin base material and a resin layer disposed on one surface of the resin base material, and has the uneven structure on the surface of the resin layer. The uneven resin film according to any one of claims 1 to 1. The uneven resin film according to any one of claims 1 to 6, wherein the uneven resin film has a resin substrate, and the surface of the resin substrate has the uneven structure. A laminated film comprising the uneven resin film according to any one of claims 1 to 8. 10. The laminated film according to claim 9, which has an adhesive layer on the surface opposite to the uneven structure of the uneven resin film. 11. The laminated film according to claim 9, wherein the uneven resin film has a printed layer on the surface opposite to the uneven structure.

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