Uneven resin film and laminate film

Abstract

To provide an uneven resin film having an uneven structure capable of reducing pressure resistance on its surface.SOLUTION: In an uneven structure of an uneven resin film 1, uneven parts 2 having a plurality of protrusions 11 and recesses 12 and flat parts 3 are alternately arranged in a first direction d1, where a height of the uneven parts 2 is 20 μm or more and 200 μm or less; a length L1 of the uneven parts 2 in a second direction d2 perpendicular to the first direction d1 is 30 mm or more; and a width W1 of the uneven parts 2 and a width W2 of the flat parts 3 in the first direction d1 are 0.2 mm or more and 50 mm or less. The uneven parts 2 have a plurality of protrusions 11 and recesses 12 extending linearly along the first direction d1. A width of the linear recesses 12 is 1 to 12 times the height H1 of the uneven parts 2. A width of the linear protrusions 11 is 1 to 2 times the height H1 of the uneven parts 12. The protrusions 11 of the uneven parts 12 protrude from the surface of the flat parts 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a concavo-convex resin film and a laminated film capable of reducing gas resistance.

Background Art

[0002] In recent years, in the fields of moving bodies moving in a fluid and fluid transfer, etc., research on fluid resistance reduction technology has been actively conducted in order to achieve energy savings and carbon dioxide reduction.

[0003] Conventionally, as a fluid resistance reduction technology, for example, it is known to provide irregularities on the surface of an object. For example, among fluid resistances, riblets are known as a method for reducing frictional resistance, and dimples are known as a method 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 and generating longitudinal vortices at the boundary between the rough surface and the smooth surface to suppress the separation of the flow.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] 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. Further, Patent Document 2 does not mention in detail the specific shapes and configurations of the rough surface and the smooth surface.

[0006] The present disclosure has been made in view of the above circumstances, and the main object thereof is to provide a concavo-convex resin film and a laminated film capable of reducing pressure resistance.

Means for Solving the Problem

[0007] One embodiment of the present disclosure provides an uneven resin film having an uneven structure on the surface capable of reducing pressure resistance.

[0008] In the uneven resin film of the present disclosure, in the above uneven structure, an uneven portion having a plurality of convex portions and concave portions and a flat portion are alternately arranged in a 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, and the width of the uneven portion and the width of the flat portion in the first direction are preferably 0.2 mm or more and 50 mm or less.

[0009] In the above case, the uneven portion preferably has a plurality of the convex portions and the concave portions extending linearly along the first direction. In this case, the width of the linear concave portion is preferably 1 time or more and 12 times or less the height of the uneven portion. Also, in this case, the width of the linear convex portion is preferably 1 time or more and 2 times or less the height of the uneven portion.

[0010] Also, in the above case, the convex portion of the uneven portion preferably protrudes with respect to the surface of the flat portion.

[0011] Further, the uneven resin film of the present disclosure may have a resin base material and a resin layer disposed on one surface of the resin base material, and may have the uneven structure on the surface of the resin layer.

[0012] Further, the uneven resin film of the present disclosure may have a resin base material and may have the uneven structure on the surface of the resin base material.

[0013] Another embodiment of the present disclosure provides a laminated film having the above-described uneven resin film.

[0014] The laminated film of the present disclosure may have an adhesive layer on the surface opposite to the uneven structure of the uneven resin film.

[0015] The laminated film of the present disclosure may have a printing layer on the surface of the uneven resin film opposite to the uneven structure.

Advantages of the Invention

[0016] In the present disclosure, it is possible to provide an uneven resin film and a laminated film capable of reducing pressure resistance.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0018] The 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 modes and is not construed as being limited to the description content of the embodiments illustrated below. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual form, but this is merely an example and does not limit the interpretation of the present disclosure. Further, in this specification and each drawing, elements that are the same as those described above with respect to the previously presented drawings may be denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0019] In this specification, when expressing the aspect of arranging one member on another member, if simply expressed as "on" or "under", unless otherwise specified, it includes both the case where another member is arranged directly on or under so as to be in contact with a certain member, and the case where another member is arranged above or below a certain member with yet another member interposed therebetween. Also, in this specification, when expressing the aspect of arranging one member on the surface of another member, if simply expressed as "on the surface", unless otherwise specified, it includes both the case where another member is arranged directly on or under so as to be in contact with a certain member, and the case where another member is arranged above or below a certain member with yet another member interposed therebetween.

[0020] Also, in this specification, the terms "film" and "sheet" are not distinguished from each other based only on the difference in name. For example, "film" includes sheets.

[0021] Hereinafter, the concavo-convex resin film and the laminated film of the present disclosure will be described in detail.

[0022] A. Concavo-convex resin film The concavo-convex resin film of the present disclosure has a concavo-convex structure on the surface that can reduce pressure resistance.

[0023] The concavo-convex resin film of the present disclosure can reduce pressure resistance when applied to the surface of an object, and as a result, energy conservation and carbon dioxide reduction can be achieved. The concavo-convex resin film of the present disclosure can be applied to the surface of an object, for example, by pasting or the like, and a gas resistance reduction structure can be easily imparted to the surface of the object. Further, since the concavo-convex resin film of the present disclosure is in the form of a film, it can also be applied to a curved surface or a three-dimensional shape. Furthermore, the concavo-convex resin film of the present disclosure can be re-pasted or re-applied.

[0024] Hereinafter, each component of the concavo-convex resin film of the present disclosure will be described.

[0025] 1. Concavo-convex structure The concavo-convex structure in the present disclosure is not particularly limited as long as it can reduce pressure resistance and can generate turbulent flow. For example, a rough-smooth structure in which concavo-convex portions (rough surfaces) having a plurality of convex portions and concave portions and flat portions (smooth surfaces) are alternately arranged; a dimple structure having a plurality of concave portions; a pillar structure having a plurality of pillars; a random concavo-convex structure formed by roughening the surface by polishing with paper or a file, sandblasting, or the like; and the like can be mentioned.

[0026] Hereinafter, the rough-smooth structure and the dimple structure will be described.

[0027] (1) Rough-smooth structure In the rough-smooth structure in the present disclosure, concavo-convex portions (rough surfaces) having a plurality of convex portions and concave portions and flat portions (smooth surfaces) are alternately arranged.

[0028] Among them, in the rough-smooth structure, that is, the concavo-convex structure, the concavo-convex portions having a plurality of convex portions and concave portions and the flat portions are alternately arranged in a first direction, the height of the concavo-convex portions is 20 μm or more and 200 μm or less, the length of the concavo-convex portions in a second direction orthogonal to the first direction is 30 mm or more, and the width of the concavo-convex portions and the width of the flat portions in the first direction are preferably 0.2 mm or more and 50 mm or less.

[0029] Figs. 1(a) to 1(c) and Fig. 2 are a schematic plan view, a cross-sectional view, and a perspective view showing an example of the concavo-convex resin film of the present disclosure. Fig. 1(b) is a cross-sectional view taken along line A-A of Fig. 1(a), Fig. 1(c) is a cross-sectional view taken along line B-B 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 concavo-convex resin film 1 has a concavo-convex structure 4 on its surface. In the concavo-convex structure 4, a concavo-convex portion 2 having a plurality of convex portions 11 and concave portions 12 and a flat portion 3 are alternately arranged in a first direction d1. The height H1 of the concavo-convex portion 2 is within a predetermined range, the length L1 of the concavo-convex portion 2 in a second direction d2 orthogonal to the first direction d1 is equal to or greater than a predetermined value, and the width W1 of the concavo-convex portion 2 and the width W2 of the flat portion 3 in the first direction d1 are within a predetermined range.

[0030] Figs. 3(a) and 3(b) are schematic diagrams illustrating the flow of gas in the case where the concavo-convex resin film of the present disclosure has a concavo-convex structure in which a concavo-convex portion having a plurality of convex portions and concave portions and a flat portion are alternately arranged in a first direction. Fig. 3(b) is a cross-sectional view taken along line A-A of Fig. 3(a). As shown in Fig. 3(a), when gas F flows along the surface of the concavo-convex resin film 1, as shown in Fig. 3(b), a secondary flow, that is, a longitudinal vortex LV, is generated in the vicinity of the boundary parallel to the flow direction d3 of the gas F between the concavo-convex portion 2 and the flat portion 3. Therefore, the separation of the flow from the surface of the concavo-convex resin film 1 can be suppressed.

[0031] In the above concavo-convex structure, by making the length L1 of the concavo-convex portion 2 in the second direction d2 equal to or greater than a predetermined value, a longitudinal vortex LV can be surely generated in the vicinity of the boundary between the concavo-convex portion 2 and the flat portion 3.

[0032] Here, when an object is placed in the flow of gas, the drag acting on the object includes, for example, pressure drag and frictional drag, etc. Pressure drag is generated by the separation of the flow. Pressure drag becomes a problem in, for example, moving bodies such as automobiles, trains, and airplanes; pipes such as ducts and gas pipes; wind turbines; air conditioning equipment; etc. The flow velocity of the gas flowing through these objects 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).

[0033] In the uneven structure described above, for example, when the flow velocity of the gas flowing over an object is within the above range, by appropriately adjusting the height H1 of the uneven portion 2 within a predetermined range, it is possible to easily generate a longitudinal vortex LV in the vicinity of the boundary between the uneven portion 2 and the flat portion 3.

[0034] Here, in the flow around an object, in a very thin layer on the object surface, it is strongly affected by viscosity. The layer that is strongly affected by this viscosity is called the boundary layer.

[0035] Figs. 4(a) to 4(c) are schematic diagrams showing the relationship between the widths of the uneven portions and the flat portions in the first direction and the longitudinal vortices generated near the boundaries of the uneven portions and the flat portions when the uneven resin film has an uneven structure in which a plurality of convex portions and concave portions and flat portions are alternately arranged in the first direction on the surface. For example, as shown in Fig. 4(a), when the width W1 of the uneven portion 2 and the width W2 of the flat portion 3 in the first direction are large, although a large longitudinal vortex LV is generated near the boundary between the uneven portion 2 and the flat portion 3, it is difficult for the longitudinal vortex LV to reach the central portion of the uneven portion 2 and the central portion of the flat portion 3. Further, for example, as shown in Fig. 4(c), 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 longitudinal vortex LV generated near the boundary between the uneven portion 2 and the flat portion 3 is small, and it is difficult for the longitudinal vortex LV to reach the outer edge of the boundary layer. In these cases, although the separation of the flow can be suppressed, the effect is small. In Figs. 4(a) to 4(c), δ indicates the boundary layer thickness.

[0036] On the other hand, in the uneven structure described above, since 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, for example, as shown in Fig. 4(b), a large longitudinal vortex LV is generated near the boundary between the uneven portion 2 and the flat portion 3, and the longitudinal vortex LV can be generated throughout the boundary layer.

[0037] Therefore, in the concavo-convex structure described above, the concavo-convex portions having a plurality of convex portions and concave portions and the flat portions are alternately arranged in the first direction, the length of the concavo-convex portions in the second direction orthogonal to the first direction is equal to or greater than a predetermined value, the height of the concavo-convex portions is within a predetermined range, and the widths of the concavo-convex portions and the flat portions in the first direction are within a predetermined range, so that longitudinal vortices can be efficiently generated in the vicinity of the boundaries between the concavo-convex portions and the flat portions, and the separation of the flow can be effectively suppressed.

[0038] Hereinafter, the concavo-convex portions and the flat portions will be described.

[0039] In the concavo-convex structure according to the present disclosure, it is preferable that the concavo-convex portions having a plurality of convex portions and concave portions and the flat portions are alternately arranged in the first direction.

[0040] (a) Concavo-convex portion In the concavo-convex structure according to the present disclosure, the length of the concavo-convex portions in the second direction is preferably, for example, 30 mm or more, and more preferably 50 mm or more. If the length of the concavo-convex portions in the second direction is too short, it becomes difficult to generate longitudinal vortices in the vicinity of the boundaries between the concavo-convex portions and the flat portions, and the effect of suppressing the separation of the flow may be reduced. Further, by setting the length of the concavo-convex portions in the second direction to 50 mm or more, longitudinal vortices can be surely generated in the vicinity of the boundaries between the concavo-convex portions and the flat portions. Also, the length of the concavo-convex portions in the second direction is preferably, for example, 1000 mm or less, and more preferably 200 mm or less. If the length of the concavo-convex portions in the second direction is too long, even if the pressure resistance can be reduced, the frictional resistance may increase, and it may not be possible to sufficiently reduce the gas resistance, and the manufacturing cost may increase in some cases.

[0041] Here, the length L1 of the uneven portion 2 in the second direction d2 refers to the distance from one end to the other end of the uneven portion 2 in the second direction d2, as shown in, for example, Fig. 1(a). Also, when the surface of the uneven resin film 1 is flat as shown in, for example, Fig. 1(c), the length of the uneven portion in the second direction refers to the length L1 of the uneven portion 2 on the plane in the second direction d2, as shown in, for example, Fig. 1(a). Further, when the surface of the uneven resin film 1 is a curved surface as shown in, for example, Fig. 5(a), the length of the uneven portion in the second direction refers to the length L1 of the uneven portion 2 on the curved surface in the second direction d2.

[0042] Also, in the uneven structure of 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, in moving bodies such as automobiles, trains, and airplanes; pipes such as ducts and gas pipes; wind turbines; air conditioning equipment; etc., the flow velocity of the gas flowing through the object is about 3 m / s or more and 250 m / s or less (about 10 km / h or more and 900 km / h or less). When the flow velocity is within the above range, by appropriately adjusting the height of the uneven portion within the above range, it is possible to easily generate longitudinal vortices near the boundary between the uneven portion and the flat portion. Also, for example, the speed of an automobile is about 10 km / h or more and 120 km / h or less. In this case, the flow velocity of the air flowing through the automobile is about 3 m / s or more and 33 m / s or less (about 10 km / h or more and 120 km / h or less). When the flow velocity is within the above range, by appropriately adjusting the height of the uneven portion within the range of 50 μm or more and 200 μm or less, it is possible to easily generate longitudinal vortices near the boundary between the uneven portion and the flat portion.

[0043] More preferably, the height of the uneven portion is about 1 / 10 or more and 1 / 100 or less of the boundary layer thickness. Also, since the boundary layer thickness becomes thinner as the flow velocity of the gas increases, it is preferable that the height of the uneven portion is lower within the above range as the flow velocity of the gas increases.

[0044] Here, the height H1 of the uneven portion 2 refers to the distance from the bottom of the concave portion 12 of the uneven portion 2 to the top of the convex portion 11, as shown in, for example, Fig. 1(c).

[0045] In addition, in the concavo-convex structure in the present disclosure, the width of the concavo-convex portion in the first direction is preferably, for example, 0.2 mm or more and 50 mm or less, and more preferably 1 mm or more and 25 mm or less. When the width of the concavo-convex portion in the first direction is within the above range, for example, as shown in FIG. 4(b), a large longitudinal vortex LV is generated near the boundary between the concavo-convex portion 2 and the flat portion 3, and the longitudinal vortex LV can be generated throughout the boundary layer.

[0046] More preferably, the width of the concavo-convex portion in the first direction is the same as the boundary layer thickness. Further, since the boundary layer thickness becomes thinner as the gas flow velocity increases, it is preferable that the width of the concavo-convex portion in the first direction is smaller within the above range as the gas flow velocity increases.

[0047] As long as the width of the concavo-convex portion in the first direction is within the above range, it may be the same as or different from the width of the flat portion in the first direction described later. Among them, it is preferable that the width of the concavo-convex 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 near the boundary between the concavo-convex portion and the flat portion.

[0048] Here, the width W1 of the concavo-convex portion 2 in the first direction d1 refers to the distance from one end to the other end of the concavo-convex portion 2 in the first direction d1, as shown in FIGS. 1(a) and (b), for example. Further, when the surface of the concavo-convex resin film 1 is a plane, as shown in FIG. 1(b) for example, the width of the concavo-convex portion in the first direction refers to the width W1 of the concavo-convex portion 2 on the plane in the first direction d1. Also, when the surface of the concavo-convex resin film 1 is a curved surface, as shown in FIG. 5(b) for example, the width of the concavo-convex portion in the first direction refers to the width W1 of the concavo-convex portion 2 on the curved surface in the first direction d1.

[0049] The concavo-convex portion has a plurality of convex portions and concave portions. In the concavo-convex portion, it is sufficient that the plurality of convex portions and concave portions are arranged so as to be uniformly distributed. The pattern shape of the convex portion and the concave portion in plan view may be, for example, a regular pattern or a random pattern. In the case of a regular pattern, for example, patterns such as a linear pattern, a dot pattern, and a lattice pattern can be mentioned.

[0050] Examples of the linear pattern include a straight line pattern; a wavy line pattern such as a sine wave and a triangular wave; and the like. Among them, the linear pattern is preferably a straight line pattern.

[0051] Also, in the dot 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. Among them, when the pattern shape of the convex portion or the concave portion in plan view is dot-shaped, the dot arrangement is preferably a triangular lattice arrangement or a rhombic lattice arrangement. In the case of such a dot arrangement, it is possible to easily generate a longitudinal vortex near the boundary between the concavo-convex portion and the flat portion.

[0052] Examples of the lattice pattern include a square lattice pattern, a rectangular lattice pattern, a triangular lattice pattern, a hexagonal lattice pattern, a rhombic lattice pattern, and a parallelogram lattice pattern.

[0053] For example, FIGS. 2 and 6 are examples in which the pattern shape of the convex portion 11 and the concave portion 12 in plan view is linear, FIGS. 7(a) to (c) are examples in which the pattern shape of the convex portion 11 in plan view is dot-shaped and is a triangular lattice arrangement, and FIGS. 8(a) to (b) are examples in which the pattern shape of the concave portion 12 in plan view is dot-shaped and is a triangular lattice arrangement. Note that FIGS. 7(b) and (c) are cross-sectional views taken along line A-A of FIG. 7(a), respectively, and FIG. 8(b) is a cross-sectional view taken along line A-A of FIG. 8(a).

[0054] When the pattern shapes of the convex and concave portions in plan view are linear, the longitudinal direction of the linear patterns of the convex and concave portions preferably intersects with the second direction orthogonal to the first direction, and is more preferably substantially perpendicular to the second direction, that is, substantially parallel to the first direction. Specifically, when the pattern shapes of the convex and concave portions are linear, the longitudinal direction of the linear patterns of the convex and concave portions preferably intersects with the second direction orthogonal to the first direction, and is preferably substantially perpendicular to the second direction, that is, substantially parallel to the first direction, as shown in FIGS. 2 and 6, for example. That is, it is preferable that the concavo-convex portion has a plurality of convex and concave portions linearly extending along the first direction. As will be described later, as shown in FIG. 3(a), for example, the concavo-convex resin film is preferably arranged and used such that the boundary line between the concavo-convex portion 2 and the flat portion 3 is substantially parallel to the flow direction d3 of the gas F. That is, as shown in FIG. 3(a), for example, the concavo-convex resin film is preferably arranged and used such that the first direction d1 is substantially perpendicular to the flow direction d3 of the gas F, that is, the second direction d2 orthogonal to the first direction d1 is substantially parallel. Therefore, when the longitudinal direction of the linear patterns of the convex and concave portions intersects with the second direction orthogonal to the first direction, the longitudinal direction of the linear patterns of the convex and concave portions can be made to intersect with the flow direction of the gas. In such a case, it is possible to easily generate longitudinal vortices in the vicinity of the boundary between the concavo-convex portion and the flat portion. Further, when the longitudinal direction of the linear patterns of the convex and concave portions is substantially perpendicular to the second direction orthogonal to the first direction, the longitudinal direction of the linear patterns of the convex and concave portions can be made substantially perpendicular to the flow direction of the gas. In such a case, it is possible to further easily generate longitudinal vortices in the vicinity of the boundary between the concavo-convex portion and the flat portion.

[0055] Further, when the longitudinal direction of the linear pattern of the convex and concave portions intersects the second direction, the angle formed by the longitudinal direction of the linear pattern and the second direction is preferably, for example, 90° ± 45°. Similarly, when the longitudinal direction of the linear pattern of the convex and concave portions intersects the second direction, the angle formed by the longitudinal direction of the linear pattern and the second direction is preferably, for example, 90° ± 45°.

[0056] That is, when the longitudinal direction of the linear pattern of the convex and concave portions intersects the gas flow direction, the angle formed by the longitudinal direction of the linear pattern and the gas flow direction is preferably, for example, 90° ± 45°. Similarly, when the longitudinal direction of the linear pattern of the convex and concave portions intersects the gas flow direction, the angle formed by the longitudinal direction of the linear pattern and the gas flow direction is preferably, for example, 90° ± 45°.

[0057] Here, that the longitudinal direction of the linear pattern of the convex and concave portions is substantially parallel to the first direction means that the angle formed by the longitudinal direction of the linear pattern and the first direction is 0° ± 5°. Similarly, that the longitudinal direction of the linear pattern of the convex and concave portions is substantially parallel to the first direction means that the angle formed by the longitudinal direction of the linear pattern and the first direction is 0° ± 5°.

[0058] Also, that the longitudinal direction of the linear pattern of the convex and concave portions is substantially perpendicular to the gas flow direction means that the angle formed by the longitudinal direction of the linear pattern and the gas flow direction is 90° ± 5°. Similarly, that the longitudinal direction of the linear pattern of the convex and concave portions is substantially perpendicular to the gas flow direction means that the angle formed by the longitudinal direction of the linear pattern and the gas flow direction is 90° ± 5°.

[0059] Note that the longitudinal direction of the linear pattern refers to, 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.

[0060] Also, in the concavo-convex portion, the convex portion may protrude with respect to the surface of the flat portion, or the concave portion may be recessed with respect to the surface of the flat portion. For example, FIGS. 2 and 7(b) are examples where the convex portion 11 of the concavo-convex portion 2 protrudes with respect to the surface of the flat portion 3, and FIGS. 6, 7(c), and 8(b) are examples where the concave portion 12 of the concavo-convex portion 2 is recessed with respect to the surface of the flat portion 3.

[0061] Among them, it is preferable that the convex portion protrudes with respect to the surface of the flat portion. In such a case, it is possible to easily generate longitudinal vortices in the vicinity of the boundary between the concavo-convex portion and the flat portion.

[0062] Therefore, as shown in FIG. 2 for example, it is particularly preferable that the concavo-convex portion 2 has a plurality of convex portions 11 and concave portions 12 that extend linearly along the first direction d1, and the convex portions 11 protrude with respect to the surface of the flat portion 3. In such a case, longitudinal vortices can be efficiently generated in the vicinity of the boundary between the concavo-convex portion and the flat portion.

[0063] Also, the cross-sectional shapes of the convex portion and the concave portion are not particularly limited, and examples include a rectangular shape, a trapezoidal shape, a triangular shape, a semi-circular shape, a semi-elliptical shape, etc. For example, FIG. 9(a) is an example where the cross-sectional shapes of the convex portion 11 and the concave portion 12 are rectangular, FIG. 9(b) is an example where the cross-sectional shapes of the convex portion 11 and the concave portion 12 are trapezoidal, FIGS. 9(c) to (e) are examples where the cross-sectional shape of the convex portion 11 is triangular, FIG. 9(f) is an example where the cross-sectional shape of the convex portion 11 is semi-elliptical, FIGS. 9(g) to (h) are examples where the cross-sectional shape of the concave portion 12 is triangular, and FIG. 9(i) is an example where the cross-sectional shape of the concave portion 12 is semi-circular.

[0064] Among them, it is preferable that the cross-sectional shape of the convex portion or the concave portion is trapezoidal, semi-circular, or semi-elliptical. In the case of these shapes, it is easy to form the concavo-convex portion, and the durability of the concavo-convex portion can be enhanced.

[0065] When the pattern shape of the convex and concave portions in plan view is linear, the width of the linear convex portion is preferably, for example, 1 to 2 times the height of the uneven portion. Specifically, when the pattern shape of the convex and concave portions is linear, the width of the linear convex portion is preferably 1 to 2 times the height of the uneven portion. If the width of the linear convex portion is too small, it may be difficult to form the uneven portion. Also, if the width of the linear convex portion is too large, it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven portion and the flat portion.

[0066] Here, the width of the linear convex portion is, for example, the width W3 of the convex portion 11 as shown in FIGS. 9(a) to (i), and refers to the largest width among the widths of the convex portion 11.

[0067] Also, when the pattern shape of the convex and concave portions in plan view is linear, the width of the linear concave portion is preferably, for example, 1 to 12 times the height of the uneven portion, and more preferably 4 to 10 times the height of the uneven portion. Specifically, when the pattern shape of the convex and concave portions in plan view is linear, the width of the linear concave portion is preferably 1 to 12 times the height of the uneven portion, and more preferably 4 to 10 times the height of the uneven portion. If the width of the linear concave portion is too small, the density of the convex portions becomes high, and it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven portion and the flat portion. Also, if the width of the linear concave portion is too large, the density of the convex portions becomes low, and it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven portion and the flat portion. Also, when the width of the linear concave portion is 4 to 10 times the height of the uneven portion, vertical vortices can be generated in the vicinity of the boundary between the uneven portion and the flat portion, and the separation of the flow can be effectively suppressed.

[0068] Here, the width of the linear concave portion is, for example, the width W4 of the concave portion 12 as shown in FIGS. 9(a) to (i), and refers to the smallest width among the widths of the concave portion 12. For example, in FIGS. 9(d), (g) to (i), the width of the concave portion 12 is zero.

[0069] In addition, when the pattern shape of the convex and concave portions in plan view is linear, the pitch of the linear convex portion is preferably, for example, 2 times or more and 14 times or less, more preferably 5 times or more and 12 times or less, with respect to the height of the uneven portion. Specifically, when the pattern shape of the convex and concave portions in plan view is linear, the pitch of the linear convex portion is preferably 2 times or more and 14 times or less, more preferably 5 times or more and 12 times or less, with respect to the height of the uneven portion. If the pitch of the linear convex portion is too small, the density of the convex portion becomes high, and it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven and flat portions. Also, if the pitch of the linear convex portion is too large, the density of the convex portion becomes low, and it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven and flat portions.

[0070] Here, the pitch of the linear convex portion is, for example, the pitch P1 of the convex portion 11 as shown in FIGS. 9(a) to (i), and refers to the distance between adjacent convex portions 11.

[0071] In addition, when the pattern shape of the convex portion in plan view is dot-shaped, the size of the dot-shaped convex portion in plan view is preferably, for example, 1 time or more and 2 times or less with respect to the height of the uneven portion. If the size of the dot-shaped convex portion is too small, it may be difficult to form the uneven portion. Also, if the size of the dot-shaped convex portion is too large, it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven and flat portions.

[0072] In addition, when the pattern shape of the concave portion in plan view is dot-shaped, the size of the dot-shaped concave portion in plan view is preferably, for example, 1 time or more and 12 times or less, and more preferably 4 times or more and 10 times or less, with respect to the height of the uneven portion. If the size of the dot-shaped concave portion 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. On the other hand, if the size of the dot-shaped concave portion is too large, the density of the convex portions decreases, 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, when the size of the dot-shaped concave portion is 4 times or more and 10 times or less the height of the uneven portion, longitudinal vortices can be generated in the vicinity of the boundary between the uneven portion and the flat portion, and peeling of the flow can be effectively suppressed.

[0073] Here, the size of the dot-shaped convex or concave portion in plan view refers to the diameter when the plan view shape of the convex or concave portion is circular, the major axis when the plan view shape of the convex or concave portion is elliptical, and the length of the diagonal when the plan view shape of the convex or concave portion is rectangular.

[0074] In addition, when the pattern shape of the convex or concave portion in plan view is dot-shaped, the pitch of the dot-shaped convex or concave portion is preferably, for example, 2 times or more and 14 times or less, and more preferably 5 times or more and 12 times or less, with respect to the height of the uneven portion. If the pitch of the dot-shaped convex or concave portion 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. On the other hand, if the pitch of the dot-shaped convex or concave portion is too large, the density of the convex portions decreases, and it may become difficult to sufficiently generate longitudinal vortices in the vicinity of the boundary between the uneven portion and the flat portion.

[0075] Here, the pitch of the dot-shaped convex or concave portion refers to the distance between adjacent convex portions or concave portions.

[0076] In addition, when the pattern shape of the convex portion in plan view is lattice-shaped, the width of the lattice-shaped convex portion is preferably, for example, 1 time or more and 2 times or less with respect to the height of the uneven portion. If the width of the lattice-shaped convex portion is too small, it may be difficult to form the uneven portion. On the other hand, if the width of the lattice-shaped convex portion is too large, it may be difficult to sufficiently generate vertical vortices near the boundary between the uneven portion and the flat portion.

[0077] In addition, when the pattern shape of the convex portion in plan view is lattice-shaped, the interval between the lattice-shaped convex portions is preferably, for example, 1 time or more and 12 times or less with respect to the height of the uneven portion, and more preferably 4 times or more and 10 times or less. If the interval between the lattice-shaped convex portions is too small, the density of the convex portions becomes high, and it may be difficult to sufficiently generate vertical vortices near the boundary between the uneven portion and the flat portion. On the other hand, if the interval between the lattice-shaped convex portions is too large, the density of the convex portions becomes low, and it may be difficult to sufficiently generate vertical vortices near the boundary between the uneven portion and the flat portion. Also, when the interval between the lattice-shaped convex portions is 4 times or more and 10 times or less the height of the uneven portion, vertical vortices can be generated near the boundary between the uneven portion and the flat portion, and the separation of the flow can be effectively suppressed.

[0078] In addition, when the pattern shape of the concave portion in plan view is lattice-shaped, the width of the lattice-shaped concave portion is preferably, for example, 1 time or more and 12 times or less with respect to the height of the uneven portion, and more preferably 4 times or more and 10 times or less. If the width of the lattice-shaped concave portion is too small, the density of the convex portions becomes high, and it may be difficult to sufficiently generate vertical vortices near the boundary between the uneven portion and the flat portion. On the other hand, if the width of the lattice-shaped concave portion is too large, the density of the convex portions becomes low, and it may be difficult to sufficiently generate vertical vortices near the boundary between the uneven portion and the flat portion. Also, when the width of the lattice-shaped concave portion is 4 times or more and 10 times or less the height of the uneven portion, vertical vortices can be generated near the boundary between the uneven portion and the flat portion, and the separation of the flow can be effectively suppressed.

[0079] Further, when the pattern shape of the concave portion in plan view is a lattice shape, the interval between the lattice-shaped concave portions is preferably, for example, 1 time or more and 2 times or less with respect to the height of the uneven portion. If the interval between the lattice-shaped concave portions is too small, it may be difficult to form the uneven portion. Also, if the interval between the lattice-shaped concave portions is too large, it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven portion and the flat portion.

[0080] Further, when the pattern shape of the convex portion or the concave portion in plan view is a lattice shape, the pitch of the lattice-shaped convex portion or concave portion is preferably, for example, 2 times or more and 14 times or less with respect to the height of the uneven portion, and more preferably 5 times or more and 12 times or less. If the pitch of the lattice-shaped convex portion or concave portion is too small, the density of the convex portion becomes high, and it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven portion and the flat portion. Also, if the pitch of the lattice-shaped convex portion or concave portion is too large, the density of the convex portion becomes low, and it may be difficult to sufficiently generate vertical vortices in the vicinity of the boundary between the uneven portion and the flat portion.

[0081] Note that the dimensions of the uneven portion, the concave portion, and the convex portion can be measured by observing the surface or the cross-section in the thickness direction of the uneven resin film with a laser microscope, a stylus-type surface profiler, or a scanning electron microscope (SEM).

[0082] The shape of the uneven portion in plan view is not particularly limited as long as it can generate vertical vortices in the vicinity of the boundary between the uneven portion and the flat portion, and examples include a rectangular shape and an arc shape. For example, FIG. 1(a) is an example in which the shape of the uneven portion 2 in plan view is a rectangular shape, and FIG. 10 is an example in which the shape of the uneven portion 2 in plan view is a rectangular shape and an arc shape. Among them, the shape of the uneven portion in plan view is preferably a rectangular shape.

[0083] In the above concavo-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 concave-convex portions and the flat portions only need to be alternately arranged in the first direction. For example, the concave-convex portions and the flat portions may be alternately arranged in parallel in the first direction, or may be alternately arranged non-parallel in the first direction. For example, FIG. 1(a) shows an example in which the concave-convex portions 2 and the flat portions 3 are alternately arranged in parallel in the first direction d1, and FIG. 10 shows an example in which the concave-convex portions 2 and the flat portions 3 are alternately arranged non-parallel in the first direction d1. For example, when applying the concavo-convex resin film to the three-dimensional curved surface of an object, the concave-convex portions and the flat portions may be alternately arranged non-parallel in the first direction. Among them, it is preferable that the concave-convex portions and the flat portions are alternately arranged in parallel in the first direction.

[0084] (b) Flat portion In the concavo-convex structure in 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. When the width of the flat portion in the first direction is within the above range, for example, as shown in FIG. 4(b), a large longitudinal vortex LV is generated near the boundary between the concave-convex portion 2 and the flat portion 3, and the longitudinal vortex LV can be generated throughout the boundary layer.

[0085] More preferably, the width of the flat portion in the first direction is the same as the boundary layer thickness. Further, since the boundary layer thickness becomes thinner as the gas flow velocity is faster, it is preferable that the width of the flat portion in the first direction is smaller within the above range as the gas flow velocity is faster.

[0086] Here, the width W2 of the flat portion 3 in the first direction d1 refers to the distance from one end to the other end of the flat portion 3 in the first direction d1 in the flat portion 3 located between adjacent uneven portions 2 as shown in FIGS. 1(a) and 1(b), for example. Also, when the surface of the uneven resin film 1 is flat as shown in FIG. 1(b), for example, the width of the flat portion in the first direction refers to the width W2 of the flat portion 3 on the plane in the first direction d1. Further, when the surface of the uneven resin film 1 is a curved surface as shown in FIG. 5(b), for example, the width of the flat portion in the first direction refers to the width W2 of the flat portion 3 on the curved surface in the first direction d1.

[0087] (2) Dimple structure The dimple structure has a plurality of concave portions.

[0088] In the dimple structure, it is sufficient that the plurality of concave portions are arranged so as to be uniformly distributed. The pattern shape of the concave portions in plan view may be, for example, a regular pattern or a random pattern.

[0089] 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 rhombic lattice arrangement, a parallelogram lattice arrangement, and the like.

[0090] The shape of the concave portion in plan view is not particularly limited, and examples thereof include a circular shape and an elliptical shape. Also, the shape of the concave portion in plan view may be irregular.

[0091] The cross-sectional shape of the concave portion is not particularly limited, and examples thereof include a semi-circular shape, a semi-elliptical shape, a trapezoidal shape, and the like.

[0092] The depth of the recess is appropriately set so as to form 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 even more preferably 0.15 mm or more and 5.0 mm or less. If the depth of the recess is too small, the volume of the recess becomes small, and thus the generation of vortices (turbulent flow) may be insufficient. On the other hand, if the depth of the recess is too large, film formation may become difficult.

[0093] The size of the recess in plan view is appropriately set so as to form 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 recess is too small, the volume of the recess becomes small, and thus the generation of vortices (turbulent flow) may be insufficient. On the other hand, if the radius of curvature of the recess is too large, film formation may become difficult.

[0094] Note that the dimensions of the recess can be measured by observing the surface or a cross-section in the thickness direction of the uneven resin film using a laser microscope, a stylus-type surface profiler, or a scanning electron microscope (SEM).

[0095] 2. Configuration of the uneven resin film The uneven resin film in the present disclosure can have at least a resin substrate. The resin film in the present disclosure only needs to have the above-mentioned uneven structure on the surface. For example, the uneven structure may be integrally formed with the resin substrate, or may be formed separately from the resin substrate. That is, the uneven resin film of the present disclosure may have a resin substrate and have the above-mentioned uneven structure on the surface of the resin substrate, or may have a resin substrate and a resin layer disposed on one surface of the resin substrate, and have the above-mentioned uneven structure on the surface of the resin layer.

[0096] In addition, when the concavo-convex resin film in the present disclosure has, as the concavo-convex structure, for example, a rough-smooth structure in which a concavo-convex portion (rough surface) having a plurality of convex portions and concave portions and a flat portion (smooth surface) are alternately arranged, for example, as shown in FIGS. 11(a) to (b), the concavo-convex portion 2 may be integrally formed with the resin substrate 10, and as shown in FIGS. 11(c) to (f), the concavo-convex portion 2 may be separately formed from the resin substrate 10. Further, when the concavo-convex portion is separately formed from the resin substrate, for example, as shown in FIGS. 11(c) to (d), the bottom of the concave portion 12 of the concavo-convex portion 2 and the flat portion 3 may be the surface of the resin substrate 10, and as shown in FIGS. 11(e) to (f), a resin layer 13 is disposed on one surface of the resin substrate 10, and the resin layer 13 may have the concavo-convex portion 2 and the flat portion 3.

[0097] The concavo-convex structure may be transparent or opaque.

[0098] As the material of the concavo-convex structure, a resin can be used. When the concavo-convex structure is integrally formed with the resin substrate, the material of the concavo-convex structure can be the same as the material of the resin substrate described later. Further, when the concavo-convex structure is separately formed from the resin substrate, examples of the material of the concavo-convex structure include cured products of curable resin compositions such as ultraviolet curable resin compositions and electron beam curable resin compositions, or curable resin compositions such as thermosetting resin compositions; thermoplastic resins; and the like.

[0099] In addition, the concavo-convex structure may contain additives such as ultraviolet absorbers, antioxidants, plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, antistatic agents, and flame retardants as necessary. When the concavo-convex structure contains an ultraviolet absorber, the weather resistance can be enhanced.

[0100] As a method for forming the concavo-convex structure, for example, a method of forming the concavo-convex structure on the resin substrate or a method of imparting a concavo-convex shape to one surface of the resin substrate may be used.

[0101] As a method for forming an uneven structure on a resin substrate, for example, a method of using a curable resin composition, applying the curable resin composition on the resin substrate in a predetermined pattern, and curing it; a method of using an ultraviolet curable resin composition, applying the ultraviolet curable resin composition on the resin substrate, pressing a mold against the coating film, irradiating ultraviolet rays to cure the ultraviolet curable resin composition, and then peeling it from the mold, so-called photopolymer method (2P method); a method of using an ionizing radiation curable resin composition, applying the ionizing radiation curable resin composition on the resin substrate, irradiating ionizing radiation such as ultraviolet rays or electron beams in a pattern, and developing, so-called lithography method; a method of forming a resin layer on the resin substrate and embossing the surface of the resin layer; and the like. Further, a resin layer having an embossed surface may be separately produced and laminated on the resin substrate.

[0102] In the case of the method of applying a curable resin composition on a resin substrate in a predetermined pattern and curing it, the application method of the curable resin composition is not particularly limited as long as it can be applied in a desired pattern. For example, an inkjet method, a screen printing method, and the like can be mentioned. Also, in the case of the photopolymer method or the lithography method, the application method of the curable resin composition is not particularly limited as long as it can be applied uniformly, and a known application method can be applied.

[0103] Also, 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 it is appropriately selected according to the use of the uneven resin film and the like. For example, when the uneven resin film of the present disclosure is used as a wrapping film or a marking film for moving bodies such as automobiles, trains, and airplanes, the thickness of the resin layer can be about 30 μm or more and 300 μm or less.

[0104] Also, as a method for imparting an uneven shape to one surface of the resin substrate, for example, a method of embossing one or both surfaces of the resin substrate can be mentioned.

[0105] When the resin substrate is integrally formed with the uneven structure, as the material of the resin substrate, for example, a thermoplastic resin can be used, and it can be appropriately selected and used from general-purpose plastics and engineering plastics. Among them, from the viewpoints of weather resistance and abrasion resistance, a vinyl chloride resin is preferable.

[0106] In addition, the resin substrate may contain additives such as plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, ultraviolet absorbers, antioxidants, antistatic agents, and flame retardants as required. When the resin substrate is integrally formed with the uneven structure and the resin substrate contains an ultraviolet absorber, the weather resistance can be enhanced.

[0107] The resin substrate may be transparent or opaque.

[0108] The thickness of the resin substrate is not particularly limited and is appropriately selected according to the use of the uneven resin film or the like. For example, when the uneven resin film of the present disclosure is used as a wrapping film or a marking film for moving bodies such as automobiles, trains, and airplanes, the thickness of the resin substrate can be about 80 μm or more and 350 μm or less.

[0109] 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 it can be an uneven resin film having an uneven structure capable of reducing pressure resistance on the surface, and is appropriately selected according to the use or the like. The uneven resin film of the present disclosure may be disposed on the entire surface of an object or on a part of the surface of the object.

[0110] In addition, the shape of the concavo-convex resin film of the present disclosure in plan view is not particularly limited as long as it can be a concavo-convex resin film having a concavo-convex structure capable of reducing pressure resistance on the surface, and is appropriately selected according to the application and the like. The shape of the concavo-convex 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, etc., or may be a complex shape.

[0111] In addition, the thickness of the entire concavo-convex resin film of the present disclosure is not particularly limited, and is appropriately selected according to the application of the concavo-convex resin film and the like. For example, it can be 35 μm or more and 350 μm or less.

[0112] 4. Applications When the concavo-convex resin film of the present disclosure has a concavo-convex structure, for example, a concavo-convex structure (rough surface) having a plurality of convex portions and concave portions and a flat portion (smooth surface) are alternately arranged, the concavo-convex resin film is preferably arranged and used such that the angle formed by the boundary line between the concavo-convex portion (rough surface) and the flat portion (smooth surface) and the gas flow direction is, for example, 0° ± 15°. That is, when the concavo-convex resin film of the present disclosure has a concavo-convex structure in which, for example, a concavo-convex portion having a plurality of convex portions and concave portions and a flat portion are alternately arranged in a first direction, the concavo-convex resin film is preferably arranged and used such that the angle formed by the first direction and the gas flow direction is, for example, 90° ± 15°.

[0113] Among them, in the above case, the concavo-convex resin film is more preferably arranged and used such that the boundary line between the concavo-convex portion 2 and the flat portion 3 is substantially parallel to the gas flow direction d3 of the gas F, as shown in, for example, FIG. 3(a). That is, in the above case, the concavo-convex resin film is more preferably arranged and used such that the first direction d1 is substantially perpendicular to the gas flow direction d3 of the gas F, as shown in, for example, FIG. 3(a), that is, the second direction d2 orthogonal to the first direction d1 is substantially parallel. Thereby, it is possible to easily generate longitudinal vortices in the vicinity of the boundary between the concavo-convex portion and the flat portion, and suppress the separation of the flow.

[0114] Here, the boundary between the uneven portion and the flat portion being substantially parallel to the gas flow direction means that the angle between the boundary between the uneven portion and the flat portion and the gas flow direction is 0°±5°, and the first direction being substantially perpendicular to the gas flow direction means that the angle between the first direction and the gas flow direction is 90°±5°.

[0115] Furthermore, when the uneven resin film of the present disclosure has an uneven structure, for example a dimple structure, the uneven resin film can be disposed arbitrarily with respect to the gas flow direction.

[0116] 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 applied to the surface of the housing or parts of a moving body that moves through gas, such as automobiles such as passenger cars, trucks, and buses; railway vehicles such as trains, bullet trains, and locomotives; aircraft such as airplanes, helicopters, and drones; and bicycles. In addition, the uneven resin film of the present disclosure can also be applied to, for example, the inner surface of a pipe such as a duct or a gas pipe; the surface of a windmill blade; the surface of an outlet or louver of an air conditioning device such as an air conditioner; and the like. Among them, the uneven resin 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. This is because, in a bluff body, the contribution of pressure resistance is large among gas resistances, and the effect of the present disclosure is significantly exhibited. As a moving body that is a bluff body, for example, preferably, a truck, a bus, and the like can be mentioned. More specifically, the uneven resin film of the present disclosure can be used as a wrapping film or marking film for a moving object.

[0117] Furthermore, 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.

[0118] In addition, the concavo-convex resin film of the present disclosure can reduce the pressure resistance among the gas resistances, and the gas is not particularly limited. The density of the gas is, for example, 0.08 kg / m 3 or more and 10 kg / m 3 or less. Among them, the gas is preferably air.

[0119] B. Laminated Film The laminated film in the present disclosure has the above-mentioned concavo-convex resin film.

[0120] Since the laminated film in the present disclosure has the above-mentioned concavo-convex resin film, by applying it to the surface of an object, the pressure resistance can be reduced, and as a result, energy saving and carbon dioxide reduction can be achieved. In addition, the laminated film in the present disclosure can be applied to the surface of an object, for example, by pasting, and a gas resistance reduction structure can be easily imparted to the surface of the object. Further, since the laminated film in the present disclosure is in the form of a film, it can also be applied to curved surfaces and three-dimensional shapes. Furthermore, the laminated film in the present disclosure can also be re-pasted or re-applied.

[0121] Hereinafter, each component of the laminated film in the present disclosure will be described.

[0122] 1. Concavo-Convex Resin Film Since the concavo-convex resin film in the present disclosure has been described in detail in the section of "A. Concavo-Convex Resin Film" above, the description here will be omitted.

[0123] 2. Other Components The laminated film in the present disclosure may further have other components in addition to the concavo-convex resin film.

[0124] (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, for example, Fig. 12(a). The adhesive layer is a layer for attaching the uneven resin film to the surface of an object. By disposing 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.

[0125] The adhesive used for the adhesive layer is appropriately selected according to the use of the laminated film and the like. For example, acrylic adhesives, urethane adhesives, silicone adhesives, rubber adhesives, vinyl ether adhesives, and the like can be mentioned.

[0126] Further, the adhesive layer may or may not have re-peelability, but among them, it preferably has peelability. When the adhesive layer has re-peelability, it is possible to reattach the laminated film to the surface of the object when attaching the laminated film to the surface of the object, and when reattaching or removing the laminated film, it is possible to peel the laminated film from the object without leaving adhesive residue.

[0127] Note that "re-peelability" refers to the property that after attaching the laminated film to the surface of an object, it can be easily peeled off without damaging the object and without leaving the adhesive on the surface of the object.

[0128] Further, the adhesive layer may contain a colorant. By containing a colorant in the adhesive layer, shielding properties can be imparted. For example, when the surface of an article has a design, if the adhesive layer contains a colorant and the laminated film further has a printing layer as described later, by attaching the laminated film to the surface of the article, the design can be hidden and a new design can be applied.

[0129] The thickness of the adhesive layer is not particularly limited and is appropriately selected according to the use of the laminated film and the like. For example, when the laminated film in the present disclosure is used as a wrapping film or a marking film for moving bodies such as automobiles, trains, and airplanes, 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 the object may be insufficient.

[0130] 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.

[0131] Further, a separator may be disposed on the surface of the adhesive layer opposite to the uneven resin film.

[0132] (2) Printing layer The laminated film in the present disclosure may have a printing layer on the surface opposite to the uneven structure of the uneven resin film. By having a printing layer on the laminated film, a design property can be imparted.

[0133] The printing layer can display information such as characters, numbers, symbols, patterns, designs, marks, and the like.

[0134] Further, as a method for forming the printing layer, for example, the printing layer may be formed by directly printing on the resin base material of the uneven resin film, or, for example, as shown in FIG. 12(b), the printing layer 23 may be formed by printing on the support 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. Further, the printing method is not particularly limited.

[0135] The support layer is not particularly limited as long as printing can be performed, and for example, a resin base material can be used.

[0136] Further, the support layer may contain a colorant. By containing a colorant 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 printing layer and the support layer contains a colorant, by attaching the laminated film to the surface of the article, the design can be hidden and a new design can be applied.

[0137] The thickness of the support layer is not particularly limited and is appropriately selected according to the use of the laminated film and the like.

[0138] Also, when forming a printing layer by printing on the support layer, for example, as shown in FIG. 12(b), a printing sheet having a support layer 22 and a printing layer 23 disposed on one surface of the support layer 22 may be separately produced, and this printing sheet may be bonded to the resin base material 10 via a second adhesive layer 24, or a printing layer, a resin base material, and a resin layer may be sequentially formed on the support layer.

[0139] (3) Protective layer The laminated film in the present disclosure may have a protective layer on the surface of the uneven resin film on the uneven structure side. The protective layer can protect the uneven structure and improve the abrasion resistance.

[0140] When a protective layer is disposed on the surface of the uneven resin film on the uneven structure side, it is preferable that the dimensions of the unevenness on the surface of the laminated film on the protective layer side satisfy the dimensions of the uneven structure of the above-described uneven resin film.

[0141] As the material of the protective layer, for example, a resin can be used. Among them, from the viewpoints of weather resistance and abrasion resistance, an electron beam curable resin and a fluororesin are preferable.

[0142] Further, the protective layer may contain additives such as an ultraviolet absorber, an antioxidant, a plasticizer, a stabilizer, a lubricant, a filler, a colorant, a processing aid, an antistatic agent, and a flame retardant, if necessary. When the protective layer contains an ultraviolet absorber, the weather resistance can be enhanced.

[0143] The thickness of the protective layer is preferably, for example, 0.01 μm or more and 10 μm or less.

[0144] 3. Size and Shape of the Laminate Film The size of the laminate film in plan view in the present disclosure is appropriately selected according to the use and the like. The laminate film in the present disclosure may be disposed on the entire surface of an object or on a part of the surface of the object.

[0145] In addition, the shape of the laminate film in plan view in the present disclosure is appropriately selected according to the use and the like, and for example, it can be the same as the shape of the concavo-convex resin film in plan view.

[0146] 4. Use In the present disclosure, the arrangement of the laminate film with respect to the gas flow direction is appropriately set according to the type of the concavo-convex structure of the concavo-convex resin film, and can be the same as the arrangement of the concavo-convex resin film with respect to the gas flow direction described above.

[0147] The use of the laminate film in the present disclosure can be the same as the use of the concavo-convex resin film described above.

[0148] Note that the present disclosure is not limited to the above-described embodiments. The above-described embodiments are examples, and those having a configuration substantially the same as the technical idea described in the claims of the present disclosure and exhibiting the same operational effects are included in the technical scope of the present disclosure regardless of what they are.

Example

[0149] Hereinafter, examples and comparative examples will be shown to further explain the present disclosure.

[0150] [Examples 1 to 11] First, a printing master roll (Avery Dennison's "MPI1105") having a vinyl chloride resin film, an adhesive layer, and a release paper in this order was used, and a pattern was printed on the vinyl chloride resin film of the printing master roll to form a printing layer. Next, a laminate film (Avery Dennison's "DOL1460") having a vinyl chloride resin film, an adhesive layer, and a release paper in this order was used. After peeling the release paper from the laminate film, the laminate film was laminated on the printing layer. Next, on the vinyl chloride resin film of the laminate film, using a UV inkjet device, UV curable ink was ejected and cured to form uneven portions having a plurality of linear convex portions and concave portions. Further, as shown in Fig. 1(a), the uneven portions were formed such that the uneven portions and the flat portions were alternately arranged in a stripe shape. The dimensions of the uneven portions and the flat portions were as shown in Table 1. Thereby, a wrapping film was produced.

[0151] [Evaluation] The wrapping films of Examples 1 to 11 were attached to a track-shaped model (length 1250 mm, width 260 mm, height 387 mm), and a wind tunnel experiment was conducted to measure the air resistance coefficient (Cd value) under the condition of a wind speed of 25 m / s. Further, the case where the wrapping film was not attached was used as a comparative example.

[0152] [Table 1]

[0153] In Examples 1 to 11, it was confirmed that the Cd value became smaller and the gas resistance was reduced as compared with the comparative example. Among them, in Examples 1 to 7, since 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 were all within a predetermined range, the gas resistance reduction effect was larger than that in Examples 8 to 11. [Explanation of Reference Numerals]

[0154] 1... Uneven resin film 2... Uneven portion 3... Flat portion 4 … Concave-convex structure 10 … Resin substrate 11 … Protrusion 12 … Recess 20 … Laminated film 21 … Adhesive layer 23 … Printing layer d1 … First direction d2 … Second direction H1 … Height of the concave-convex part L1 … Length of the concave-convex part in the second direction W1 … Width of the concave-convex part in the first direction W2 … Width of the flat part in the first direction

Claims

【Claim 1】 An uneven resin film having an uneven structure on its surface capable of reducing pressure resistance.

Images