Textured resin film and laminated film

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

[Technical field]

[0001] The present disclosure relates to a concave-convex resin film and a laminate film capable of reducing gas resistance. [Background technology]

[0002] 2. Description of the Related Art In recent years, in the fields of moving objects that move through fluids and fluid transport, research into fluid resistance reduction technology has been actively conducted in order to achieve energy savings and carbon dioxide reduction.

[0003] Conventionally, as a technique for reducing fluid resistance, for example, providing irregularities on the surface of an object is known. For example, riblets are known as a technique for reducing frictional resistance among fluid resistances, and dimples are known as a technique for reducing pressure resistance (for example, Patent Document 1). Furthermore, Patent Document 2 discloses a technical idea of ​​arranging rough surfaces and smooth surfaces to generate longitudinal vortices at the boundary between the rough surfaces and the smooth surfaces, thereby suppressing flow separation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2010 / 29844 [Patent Document 2] JP 2013-57390 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is no specific disclosure of a means for applying a fluid resistance reduction structure to the surface of an object in Patent Document 1 or Patent Document 2. Furthermore, 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 consideration of the above-mentioned circumstances, and has as its main object to provide a concave-convex resin film and a laminate film that can reduce pressure resistance. [Means for solving the problem]

[0007] One embodiment of the present disclosure provides an uneven resin film having an uneven structure on a surface thereof that can reduce pressure resistance.

[0008] In the uneven resin film of the present disclosure, the uneven structure has uneven portions having a plurality of protrusions and recesses and flat portions arranged alternately in a first direction, and it is preferable that the height of the uneven portions is 20 μm or more and 200 μm or less, the length of the uneven portions in a second direction perpendicular to the first direction is 30 mm or more, and the width of the uneven portions and the width of the flat portions in the first direction are 0.2 mm or more and 50 mm or less.

[0009] In the above case, the concave-convex 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 to 12 times the height of the concave-convex portion. Also, in this case, the width of the linear convex portion is preferably 1 to 2 times the height of the concave-convex portion.

[0010] In the above case, it is preferable that the protrusions of the uneven portion protrude beyond the surface of the flat portion.

[0011] Furthermore, 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 the uneven structure may be provided on the surface of the resin layer.

[0012] Furthermore, the uneven resin film of the present disclosure may have a resin substrate, and the uneven structure may be provided on the surface of the resin substrate.

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

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

[0015] The laminate film of the present disclosure may have a printed layer on the surface of the uneven resin film opposite to the uneven structure. Effect of the Invention

[0016] The present disclosure can provide a concave-convex resin film and a laminate film that can reduce pressure resistance. [Brief description of the drawings]

[0017] [Figure 1] 1A and 1B are schematic plan and cross-sectional views illustrating an example of an uneven resin film according to the present disclosure. [Diagram 2] FIG. 1 is a schematic perspective view illustrating an example of an uneven resin film according to the present disclosure. [Diagram 3] 2 is a schematic diagram illustrating a gas flow in the uneven resin film of the present disclosure. FIG. [Figure 4] 3A and 3B are schematic diagrams illustrating gas flows in a concave-convex resin film. [Diagram 5] 1 is a schematic cross-sectional view illustrating an example of an uneven resin film according to the present disclosure. [Figure 6] FIG. 1 is a schematic perspective view illustrating an example of an uneven resin film according to the present disclosure. [Figure 7] 1A and 1B are schematic plan and cross-sectional views illustrating an example of an uneven resin film according to the present disclosure. [Figure 8] 1A and 1B are schematic plan and cross-sectional views illustrating an example of an uneven resin film according to the present disclosure. [Figure 9] 2 is a schematic cross-sectional view illustrating an example of an uneven portion in the uneven resin film of the present disclosure. FIG. [Figure 10] 1 is a schematic plan view illustrating an example of an uneven resin film according to the present disclosure. [Figure 11] 1 is a schematic cross-sectional view illustrating an example of an uneven resin film according to the present disclosure. [Figure 12] 1 is a schematic cross-sectional view illustrating a laminated film of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following describes the embodiments of the present disclosure with reference to the drawings. However, the present disclosure can be implemented in many different forms, and should not be interpreted as being limited to the description of the embodiments exemplified below. In addition, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual form in order to make the explanation clearer, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0019] In this specification, when describing a mode in which another component is disposed on a certain component, the term "above" or "below" is intended to include both a case in which another component is disposed directly above or below a certain component so as to be in contact with the component, and a case in which another component is disposed above or below a certain component with another component interposed therebetween, unless otherwise specified. Also, in this specification, when describing a mode in which another component is disposed on the surface of a certain component, the term "on the surface" is intended to include both a case in which another component is disposed directly above or below a certain component so as to be in contact with the component, and a case in which another component is disposed above or below a certain component with another component interposed therebetween, unless otherwise specified.

[0020] In addition, in this specification, the terms "film" and "sheet" are not distinguished from each other merely based on the difference in name. For example, "film" also includes a sheet.

[0021] The uneven resin film and laminate film of the present disclosure will be described in detail below.

[0022] A. Textured resin film The uneven resin film of the present disclosure has an uneven structure on its surface that can reduce pressure resistance.

[0023] The uneven resin film of the present disclosure can reduce pressure resistance by applying it to the surface of an object, thereby realizing energy saving and carbon dioxide reduction. The uneven resin film of the present disclosure can be applied to the surface of an object by, for example, pasting, and can easily impart a gas resistance reducing structure to the surface of the object. In addition, since the uneven resin film of the present disclosure is in the form of a film, it can also be applied to curved surfaces and three-dimensional shapes. Furthermore, the uneven resin film of the present disclosure can be re-pasted or replaced.

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

[0025] 1.Uneven structure The uneven structure in the present disclosure is not particularly limited as long as it is an uneven structure capable of reducing pressure resistance and generating turbulence, and examples include a rough-smooth structure in which uneven portions (rough surfaces) having multiple convex and concave portions and flat portions (smooth surfaces) are arranged alternately; a dimple structure having multiple concave portions; a pillar structure having multiple pillars; a random uneven structure formed by roughening the surface by polishing with sandpaper, sandblasting, etc.; and the like.

[0026] The rough-smooth structure and the dimple structure will be described below.

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

[0028] In particular, in the rough-and-smooth structure, i.e., the uneven structure, uneven portions having multiple protrusions and recesses and flat portions are alternately arranged in a first direction, the height of the uneven portions is 20 μm or more and 200 μm or less, the length of the uneven portions in a second direction perpendicular to the first direction is 30 mm or more, and the width of the uneven 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] 1(a)-(c) and 2 are schematic plan views, cross-sectional views and perspective views showing an example of the uneven resin film of the present disclosure, in which FIG. 1(b) is a cross-sectional view taken along line AA in FIG. 1(a), FIG. 1(c) is a cross-sectional view taken along line BB in FIG. 1(a), and FIG. 2 is a perspective view of FIG. 1(a). As shown in FIGS. 1(a)-(c) and 2, the uneven resin film 1 has an uneven structure 4 on its surface, in which uneven portions 2 having a plurality of convex portions 11 and concave portions 12 and flat portions 3 are alternately arranged in a first direction d1. The height H1 of the uneven portions 2 is within a predetermined range, the length L1 of the uneven portions 2 in a second direction d2 perpendicular to the first direction d1 is equal to or greater than a predetermined value, and the width W1 of the uneven portions 2 and the width W2 of the flat portions 3 in the first direction d1 are within a predetermined range.

[0030] 3(a) and (b) are schematic diagrams illustrating the flow of gas when the uneven resin film of the present disclosure has an uneven structure in which uneven portions having a plurality of convex and concave portions and flat portions are alternately arranged in a first direction on the surface, and FIG. 3(b) is a cross-sectional view taken along line AA in FIG. 3(a). When gas F flows along the surface of the uneven resin film 1 as shown in FIG. 3(a), a secondary flow, i.e., a vertical vortex LV, is generated near the boundary between the uneven portion 2 and the flat portion 3, which is parallel to the flow direction d3 of the gas F, as shown in FIG. 3(b). Therefore, separation of the flow from the surface of the uneven resin film 1 can be suppressed.

[0031] In the above-described uneven structure, since the length L1 of the uneven portion 2 in the second direction d2 is equal to or greater than a predetermined value, vertical vortices LV can be reliably generated near the boundary between the uneven portion 2 and the flat portion 3.

[0032] When an object is placed in a gas flow, the drag acting on the object includes, for example, pressure resistance and friction resistance, and pressure resistance occurs due to flow separation. Pressure resistance is a problem in, for example, moving objects such as automobiles, trains, and airplanes; pipes such as ducts and gas pipes; wind turbines; air conditioning equipment; and the flow speed of the gas flowing through these objects is, for example, about 3 m / s to 250 m / s (about 10 km / h to 900 km / h).

[0033] In the above-mentioned uneven structure, for example, when the flow velocity of the gas flowing through the object is within the above-mentioned range, by appropriately adjusting the height H1 of the uneven portion 2 within a predetermined range, it is possible to make it easier for longitudinal vortices LV to be generated near the boundary between the uneven portion 2 and the flat portion 3.

[0034] In the flow around an object, a very thin layer on the object's surface is strongly affected by viscosity. This layer that is strongly affected by viscosity is called the boundary layer.

[0035] 4(a)-(c) are schematic diagrams 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 when the uneven resin film has an uneven structure in which the uneven portion having a plurality of convex portions and concave portions and the flat portion are alternately arranged in the first direction. 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, a large longitudinal vortex LV is generated near the boundary between the uneven portion 2 and the flat portion 3, but the longitudinal vortex LV is difficult to reach the center portion of the uneven portion 2 and the center portion of the flat portion 3. Also, 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 the longitudinal vortex LV is difficult to reach the outer edge of the boundary layer. In these cases, the separation of the flow can be suppressed, but the effect is small. In addition, in Figures 4(a) to (c), δ represents the boundary layer thickness.

[0036] In contrast, in the above-mentioned uneven structure, 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, a large longitudinal vortex LV is generated near the boundary between the uneven portion 2 and the flat portion 3, as shown in Figure 4(b), for example, and the longitudinal vortex LV can be generated throughout the entire boundary layer.

[0037] Therefore, in the above-mentioned uneven structure, uneven portions having multiple convex portions and concave portions and flat portions are arranged alternately in a first direction, the length of the uneven portions in a second direction perpendicular to the first direction is equal to or greater than a predetermined value, the height of the uneven portions is within a predetermined range, and the width of the uneven portions in the first direction and the width of the flat portions are within a predetermined range, so that vertical vortices can be efficiently generated near the boundaries between the uneven portions and the flat portions, and flow separation can be effectively suppressed.

[0038] The uneven portion and the flat portion will be described below.

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

[0040] (a) Uneven part In the uneven structure of the present disclosure, the length of the uneven portion in the second direction is, for example, preferably 30 mm or more, more preferably 50 mm or more. If the length of the uneven portion in the second direction is too short, vertical vortices are unlikely to be generated near the boundary between the uneven portion and the flat portion, and the effect of suppressing flow separation may be reduced. In addition, by having the length of the uneven portion in the second direction be 50 mm or more, vertical vortices can be reliably generated near the boundary between the uneven portion and the flat portion. In addition, the length of the uneven portion in the second direction is, for example, preferably 1000 mm or less, 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 friction resistance increases, and it may not be possible to sufficiently reduce the gas resistance, and the manufacturing cost may increase.

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

[0042] 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, more preferably 50 μm or more and 200 μm or less. As described above, for example, in objects such as moving bodies such as automobiles, trains, and aircraft, pipes such as ducts and gas pipes, windmills, and air conditioning equipment, the flow speed 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), and when the flow speed is within the above range, by appropriately adjusting the height of the uneven portion within the above range, it is possible to easily generate vertical vortices near the boundary between the uneven portion and the flat portion. Furthermore, for example, the speed of a car 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 car 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, 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 make it easier for vertical vortices to occur near the boundary between the uneven portion and the flat portion.

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

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

[0045] 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 to 50 mm, more preferably 1 mm to 25 mm. By having the width of the concave-convex portion in the first direction within the above range, large longitudinal vortices LV are generated near the boundary between the concave-convex portion 2 and the flat portion 3, as shown in FIG. 4(b), for example, and longitudinal vortices LV can be generated throughout the boundary layer.

[0046] It is more preferable that the width of the uneven portion in the first direction is the same as the boundary layer thickness. Also, since the boundary layer thickness becomes thinner as the gas flow velocity increases, it is preferable that the width of the uneven portion in the first direction is smaller within the above range as the gas flow velocity increases.

[0047] The width of the concave-convex portion in the first direction may be the same as or different from the width of the flat portion in the first direction described below, so long as it is within the above range. In particular, it is preferable that the width of the concave-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 concave-convex portion and the flat portion.

[0048] Here, the width W1 of the concave-convex portion 2 in the first direction d1 refers to the distance from one end to the other end of the concave-convex portion 2 in the first direction d1, as shown in Figures 1(a) and 1(b), for example. In addition, when the surface of the concave-convex resin film 1 is flat, as shown in Figure 1(b), for example, the width of the concave-convex portion in the first direction refers to the width W1 of the concave-convex portion 2 on the flat surface in the first direction d1. In addition, when the surface of the concave-convex resin film 1 is curved, as shown in Figure 5(b), for example, the width of the concave-convex portion in the first direction refers to the width W1 of the concave-convex portion 2 on the curved surface in the first direction d1.

[0049] The uneven portion has a plurality of convex portions and concave portions. In the uneven portion, the plurality of convex portions and concave portions may be arranged so as to be uniformly distributed. The pattern shape of the convex portions and concave portions in a plan view may be, for example, a regular pattern or a random pattern. In the case of a regular pattern, for example, a line-like, dot-like, lattice-like pattern, etc. may be mentioned.

[0050] Examples of the line pattern include a straight line pattern, a wavy line pattern such as a sine wave pattern or a triangular wave pattern, etc. Among these, the line pattern is preferably a straight line pattern.

[0051] In the dot pattern, the dot arrangement may be, for example, a square lattice arrangement, a rectangular lattice arrangement, a triangular lattice arrangement, a hexagonal lattice arrangement, a rhombic lattice arrangement, a parallelogram lattice arrangement, etc. Among these, when the pattern shape of the convex or concave portions 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 a dot arrangement, it is possible to easily generate longitudinal vortices near the boundary between the concave and convex portions 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, Figures 2 and 6 show examples in which the pattern shape of the convex portions 11 and the concave portions 12 in a plan view is linear, Figures 7(a) to (c) show examples in which the pattern shape of the convex portions 11 in a plan view is dot-like and has a triangular lattice arrangement, and Figures 8(a) to (b) show examples in which the pattern shape of the concave portions 12 in a plan view is dot-like and has a triangular lattice arrangement. Figures 7(b) and (c) are cross-sectional views taken along line AA in Figure 7(a), and Figure 8(b) is a cross-sectional view taken along line AA in Figure 8(a).

[0054] When the pattern shape of the convex portions and the concave portions in a plan view is a line shape, the longitudinal direction of the linear pattern of the convex portions and the concave portions preferably intersects with the second direction perpendicular to the first direction, and more preferably is substantially perpendicular to the second direction, i.e., is substantially parallel to the first direction. Specifically, when the pattern shape of the convex portions and the concave portions is a straight line, the longitudinal direction of the linear pattern of the convex portions and the concave portions preferably intersects with the second direction perpendicular to the first direction, and is preferably substantially perpendicular to the second direction, i.e., is substantially parallel to the first direction, as shown in, for example, FIG. 2 and FIG. 6. That is, the concave-convex portion preferably has a plurality of convex portions and concave portions extending linearly along the first direction. As described later, the above-mentioned concave-convex resin film is preferably used by being arranged so that the boundary line between the concave-convex portion 2 and the flat portion 3 is substantially parallel to the flow direction d3 of the gas F, as shown in, for example, FIG. 3(a). That is, the above-mentioned uneven resin film is preferably arranged and used so that the first direction d1 is substantially perpendicular to the flow direction d3 of the gas F, that is, so that the second direction d2 perpendicular to the first direction d1 is substantially parallel to the flow direction d3, as shown in FIG. 3(a), for example. Therefore, when the longitudinal direction of the linear pattern of the convex portions and the concave portions intersects with the second direction perpendicular to the first direction, the longitudinal direction of the linear pattern of the convex portions and the concave portions can be made to intersect with the flow direction of the gas. In such a case, it is possible to easily generate a longitudinal vortex in the vicinity of the boundary between the uneven portion and the flat portion. In addition, when the longitudinal direction of the linear pattern of the convex portions and the concave portions is substantially perpendicular to the second direction perpendicular to the first direction, the longitudinal direction of the linear pattern of the convex portions and the 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 a longitudinal vortex in the vicinity of the boundary between the uneven portion and the flat portion.

[0055] In addition, when the longitudinal direction of the line-shaped pattern of the protrusions and recesses intersects with the second direction, the angle between the longitudinal direction of the line-shaped pattern and the second direction is preferably, for example, 90°±45°. Similarly, when the longitudinal direction of the linear pattern of the protrusions and recesses intersects with the second direction, the angle between 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 portions and the concave portions intersects with the gas flow direction, the angle between 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 portions and the concave portions intersects with the gas flow direction, the angle between the longitudinal direction of the linear pattern and the gas flow direction is preferably, for example, 90°±45°.

[0057] Here, the longitudinal direction of the line-shaped pattern of the protrusions and recesses being substantially parallel to the first direction means that the angle between the longitudinal direction of the line-shaped pattern and the first direction is 0°±5°. Similarly, the longitudinal direction of the linear pattern of the protrusions and recesses being substantially parallel to the first direction means that the angle between the longitudinal direction of the linear pattern and the first direction is 0°±5°.

[0058] Furthermore, the longitudinal direction of the line-shaped pattern of the protrusions and recesses being substantially perpendicular to the gas flow direction means that the angle between the longitudinal direction of the line-shaped pattern and the gas flow direction is 90°±5°.Similarly, the longitudinal direction of the linear pattern of the protrusions and recesses being substantially perpendicular to the gas flow direction means that the angle between the longitudinal direction of the linear pattern and the gas flow direction is 90°±5°.

[0059] The longitudinal direction of a line pattern refers to, for example, the direction in which the linear pattern extends in the case of a straight line pattern, and refers to the direction in which the wavy line pattern extends in the case of a wavy line pattern.

[0060] In the uneven portion, the convex portions may protrude from the surface of the flat portion, and the concave portions may be recessed from the surface of the flat portion. For example, Fig. 2 and Fig. 7(b) show examples in which the convex portions 11 of the uneven portion 2 protrude from the surface of the flat portion 3, while Fig. 6, Fig. 7(c) and Fig. 8(b) show examples in which the concave portions 12 of the uneven portion 2 are recessed from the surface of the flat portion 3.

[0061] In particular, it is preferable that the convex portion protrudes from the surface of the flat portion, because in this case, it is possible to easily generate longitudinal vortices in the vicinity of the boundary between the concave-convex portion and the flat portion.

[0062] 2, it is particularly preferable that the uneven portion 2 has a plurality of protrusions 11 and recesses 12 that extend linearly along the first direction d1, and that the protrusions 11 protrude from the surface of the flat portion 3. In such a case, it is possible to efficiently generate longitudinal vortices near the boundaries between the uneven portion and the flat portion.

[0063] In addition, the cross-sectional shapes of the convex portions and the concave portions are not particularly limited, and examples thereof include a rectangular shape, a trapezoidal shape, a triangular shape, a semicircular shape, a semi-elliptical shape, etc. For example, Fig. 9(a) is an example in which the cross-sectional shapes of the convex portions 11 and the concave portions 12 are rectangular, Fig. 9(b) is an example in which the cross-sectional shapes of the convex portions 11 and the concave portions 12 are trapezoidal, Fig. 9(c) to (e) are an example in which the cross-sectional shape of the convex portions 11 is triangular, Fig. 9(f) is an example in which the cross-sectional shape of the convex portions 11 is semi-elliptical, Fig. 9(g) to (h) are an example in which the cross-sectional shape of the concave portions 12 is triangular, and Fig. 9(i) is an example in which the cross-sectional shape of the concave portions 12 is semicircular.

[0064] Among these, the cross-sectional shape of the projections or recesses is preferably a trapezoid, semicircular or semi-elliptical shape, since these shapes facilitate the formation of the projections and recesses and also enhance the durability of the projections and recesses.

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

[0066] Here, the width of the linear convex portion is, for example, 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] In addition, when the pattern shape of the convex portions and the concave portions in plan view is a line shape, the width of the line-shaped concave portions is, for example, preferably 1 to 12 times, more preferably 4 to 10 times, the height of the concave portions. Specifically, when the pattern shape of the convex portions and the concave portions in plan view is a straight line, the width of the straight line-shaped concave portions is preferably 1 to 12 times, more preferably 4 to 10 times, the height of the concave portions. If the width of the line-shaped concave portions is too small, the density of the convex portions will be high, and it may be difficult to generate a longitudinal vortex sufficiently near the boundary between the concave portions and the flat portion. In addition, if the width of the line-shaped concave portions is too large, the density of the convex portions will be low, and it may be difficult to generate a longitudinal vortex sufficiently near the boundary between the concave portions and the flat portion. In addition, if the width of the line-shaped concave portions is 4 to 10 times the height of the concave portions, a longitudinal vortex can be generated near the boundary between the concave portions and the flat portion, and separation of the flow can be effectively suppressed.

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

[0069] In addition, when the pattern shape of the convex portions and the concave portions in plan view is a line shape, the pitch of the line-shaped convex portions is, for example, preferably 2 to 14 times, more preferably 5 to 12 times, the height of the concave portions. Specifically, when the pattern shape of the convex portions and the concave portions in plan view is a straight line, the pitch of the straight line-shaped convex portions is preferably 2 to 14 times, more preferably 5 to 12 times, the height of the concave portions. If the pitch of the line-shaped convex portions is too small, the density of the convex portions will be high, and it may be difficult to generate a longitudinal vortex sufficiently near the boundary between the concave portions and the flat portion. In addition, if the pitch of the line-shaped convex portions is too large, the density of the convex portions will be low, and it may be difficult to generate a longitudinal vortex sufficiently near the boundary between the concave portions and the flat portion.

[0070] Here, the pitch of the linear convex portions is, for example, the pitch P1 of the convex portions 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 to 2 times the height of the concave-convex portion. If the size of the dot-shaped convex portion is too small, it may be difficult to form the concave-convex portion. If the size of the dot-shaped convex portion is too large, it may be difficult to sufficiently generate longitudinal vortices near the boundary between the concave-convex portion and the flat portion.

[0072] In addition, when the pattern shape of the recesses in plan view is dot-shaped, the size of the dot-shaped recesses in plan view is, for example, preferably 1 to 12 times, more preferably 4 to 10 times, the height of the unevenness. If the size of the dot-shaped recesses is too small, the density of the protrusions will be high, and it may be difficult to generate a sufficient longitudinal vortex near the boundary between the unevenness and the flat portion. If the size of the dot-shaped recesses is too large, the density of the protrusions will be low, and it may be difficult to generate a sufficient longitudinal vortex near the boundary between the unevenness and the flat portion. If the size of the dot-shaped recesses is 4 to 10 times the height of the unevenness, it is possible to generate a longitudinal vortex near the boundary between the unevenness and the flat portion, and effectively suppress flow separation.

[0073] Here, the size of a dot-shaped convex or concave portion in a planar view refers to, for example, the diameter when the convex or concave portion has a circular shape in a planar view, the major axis when the convex or concave portion has an elliptical shape in a planar view, and the length of the diagonal when the convex or concave portion has a rectangular shape in a planar view.

[0074] Furthermore, when the pattern shape of the convex or concave portions in plan view is dot-shaped, the pitch of the dot-shaped convex or concave portions is, for example, preferably 2 to 14 times, more preferably 5 to 12 times, the height of the concave and convex portions. If the pitch of the dot-shaped convex or concave portions is too small, the density of the convex portions will be high, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the concave and convex portions and the flat portion. If the pitch of the dot-shaped convex or concave portions is too large, the density of the convex portions will be low, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the concave and convex portions and the flat portion.

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

[0076] In addition, when the pattern shape of the convex portion in plan view is a lattice shape, the width of the lattice-shaped convex portion is preferably, for example, 1 to 2 times the height of the concave-convex portion. If the width of the lattice-shaped convex portion is too small, it may be difficult to form the concave-convex portion. If the width of the lattice-shaped convex portion is too large, it may be difficult to sufficiently generate longitudinal vortices near the boundary between the concave-convex portion and the flat portion.

[0077] In addition, when the pattern shape of the convex portion in plan view is a lattice shape, the interval between the lattice-shaped convex portions is, for example, preferably 1 to 12 times, more preferably 4 to 10 times, the height of the concave-convex portion. If the interval between the lattice-shaped convex portions is too small, the density of the convex portions will be high, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the concave-convex portion and the flat portion. If the interval between the lattice-shaped convex portions is too large, the density of the convex portions will be low, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the concave-convex portion and the flat portion. In addition, if the interval between the lattice-shaped convex portions is 4 to 10 times the height of the concave-convex portion, longitudinal vortices can be generated near the boundary between the concave-convex portion and the flat portion, and flow separation can be effectively suppressed.

[0078] In addition, when the pattern shape of the recesses in plan view is a lattice shape, the width of the lattice-shaped recesses is, for example, preferably 1 to 12 times the height of the unevenness, and more preferably 4 to 10 times. If the width of the lattice-shaped recesses is too small, the density of the protrusions will be high, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the unevenness and the flat portion. If the width of the lattice-shaped recesses is too large, the density of the protrusions will be low, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the unevenness and the flat portion. In addition, if the width of the lattice-shaped recesses is 4 to 10 times the height of the unevenness, longitudinal vortices can be generated near the boundary between the unevenness and the flat portion, and flow separation can be effectively suppressed.

[0079] In addition, when the pattern shape of the recesses in plan view is a lattice shape, the interval between the lattice-shaped recesses is preferably, for example, 1 to 2 times the height of the uneven portion. If the interval between the lattice-shaped recesses is too small, it may be difficult to form the uneven portion. If the interval between the lattice-shaped recesses is too large, it may be difficult to sufficiently generate longitudinal vortices near the boundary between the uneven portion and the flat portion.

[0080] In addition, when the pattern shape of the convex or concave portions in plan view is a lattice shape, the pitch of the lattice-shaped convex or concave portions is, for example, preferably 2 to 14 times the height of the concave and convex portions, and more preferably 5 to 12 times. If the pitch of the lattice-shaped convex or concave portions is too small, the density of the convex portions will be high, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the concave and convex portions and the flat portion. If the pitch of the lattice-shaped convex or concave portions is too large, the density of the convex portions will be low, and it may be difficult to generate sufficient longitudinal vortices near the boundary between the concave and convex portions and the flat portion.

[0081] The dimensions of the unevenness, recesses and protrusions can be measured by observing the surface or cross section in the thickness direction of the uneven resin film with a laser microscope, a stylus 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 near the boundary between the uneven portion and the flat portion, and examples thereof include a rectangular shape, an arc shape, etc. For example, Fig. 1(a) shows an example in which the uneven portion 2 in plan view has a rectangular shape, and Fig. 10 shows an example in which the uneven portion 2 in plan view has a rectangular shape and an arc shape. Among these, the shape of the uneven portion in plan view is preferably rectangular.

[0083] In the above uneven structure, it is preferable that the uneven portions and the flat portions are alternately arranged in the first direction. In this case, it is sufficient that the uneven portions and the flat portions are alternately arranged in the first direction. For example, the uneven portions and the flat portions may be alternately arranged parallel to the first direction, or may be alternately arranged non-parallel to the first direction. For example, FIG. 1(a) is an example in which the uneven portions 2 and the flat portions 3 are alternately arranged parallel to the first direction d1, and FIG. 10 is an example in which the uneven portions 2 and the flat portions 3 are alternately arranged non-parallel to the first direction d1. For example, when applying an uneven resin film to a three-dimensional curved surface of an object, the uneven portions and the flat portions may be alternately arranged non-parallel to the first direction. In particular, it is preferable that the uneven portions and the flat portions are alternately arranged parallel to the first direction.

[0084] (b) Flat area In the concave-convex structure of the present disclosure, the width of the flat portion in the first direction is preferably 0.2 mm to 50 mm, more preferably 1 mm to 25 mm. By having the width of the flat portion in the first direction within the above range, a large longitudinal vortex LV is generated near the boundary between the concave-convex portion 2 and the flat portion 3, as shown in FIG. 4(b), for example, and the longitudinal vortex LV can be generated throughout the boundary layer.

[0085] It is more preferable that the width of the flat portion in the first direction is the same as the boundary layer thickness. Also, since the boundary layer thickness becomes thinner as the gas flow velocity increases, 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 increases.

[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 concave-convex portions 2, as shown in Figures 1(a) and 1(b), for example. In addition, in the case where the surface of the concave-convex resin film 1 is flat, as shown in Figure 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 flat surface in the first direction d1. In addition, in the case where the surface of the concave-convex resin film 1 is curved, as shown in Figure 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 recesses.

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

[0089] Examples of the arrangement of the recesses 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.

[0090] The shape of the recess in plan view is not particularly limited, and examples thereof include a circle, an ellipse, etc. The shape of the recess in plan view may be irregular.

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

[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 is small, so that the generation of vortex (turbulence) may be insufficient. Also, if the depth of the recess is too large, it may be difficult to form a film.

[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 will be small, and the generation of vortex (turbulence) may be insufficient. Also, if the radius of curvature of the recess is too large, it may be difficult to form a film.

[0094] The dimensions of the recesses can be measured by observing the surface or cross section in the thickness direction of the uneven resin film with a laser microscope, a stylus surface profiler, or a scanning electron microscope (SEM).

[0095] 2. Structure of the textured resin film The uneven resin film of the present disclosure can have at least a resin substrate. The resin film of the present disclosure may have the uneven structure on the surface, and 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 the uneven structure on the surface of the resin substrate, or may have a resin substrate and a resin layer disposed on one side of the resin substrate and the uneven structure on the surface of the resin layer.

[0096] In addition, when the uneven resin film of the present disclosure has an uneven structure in which uneven portions (rough surfaces) having a plurality of convex portions and concave portions and flat portions (smooth surfaces) are alternately arranged, for example, as shown in Figures 11(a) to (b), the uneven portions 2 may be integral with the resin substrate 10, or as shown in Figures 11(c) to (f), the uneven portions 2 may be formed separately from the resin substrate 10. In addition, when the uneven portions are formed separately from the resin substrate, for example, as shown in Figures 11(c) to (d), the bottoms of the concave portions 12 of the uneven portions 2 and the flat portions 3 may be the surfaces of the resin substrate 10, or as shown in Figures 11(e) to (f), a resin layer 13 may be arranged on one surface of the resin substrate 10, and the resin layer 13 may have the uneven portions 2 and the flat portions 3.

[0097] The relief structure may be transparent or opaque.

[0098] Resins can be used as the material of the uneven structure. When the uneven structure is integrally formed with the resin substrate, the material of the uneven structure can be the same as the material of the resin substrate described below. When the uneven structure is formed separately from the resin substrate, the material of the uneven structure can be, for example, a cured product of an ionizing radiation curable resin composition such as an ultraviolet curable resin composition or an electron beam curable resin composition, or a curable resin composition such as a thermosetting resin composition; a thermoplastic resin; and the like.

[0099] Furthermore, the uneven structure may contain additives such as ultraviolet absorbers, antioxidants, plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, antistatic agents, and flame retardants, if necessary. When the uneven structure contains an ultraviolet absorber, weather resistance can be improved.

[0100] The method for forming the uneven structure may be, for example, a method for forming an uneven structure on a resin substrate, or a method for forming an uneven shape on one surface of a resin substrate.

[0101] Examples of methods for forming an uneven structure on a resin substrate include a method in which a curable resin composition is used, the curable resin composition is applied onto a resin substrate in a predetermined pattern, and then cured; a so-called photopolymer method (2P method) in which an ultraviolet-curable resin composition is applied onto a resin substrate, a mold is pressed against the coating film, and ultraviolet rays are irradiated to cure the ultraviolet-curable resin composition, followed by peeling from the mold; a so-called lithography method in which an ionizing radiation-curable resin composition is used, the ionizing radiation-curable resin composition is applied onto a resin substrate, and ionizing radiation such as ultraviolet rays or electron beams is irradiated in a pattern and developed; a method in which a resin layer is formed on a resin substrate and the surface of the resin layer is embossed; and the like. Alternatively, a resin layer with an embossed surface may be separately prepared, and the resin layer may be laminated onto the resin substrate.

[0102] In the case of a method of applying a curable resin composition onto a resin substrate in a predetermined pattern and curing the composition, the application method of the curable resin composition is not particularly limited as long as it can apply the composition in a desired pattern, and examples of the application method include an inkjet method, a screen printing method, etc. In addition, in the case of a photopolymer method or a lithography method, the application method of the curable resin composition is not particularly limited as long as it can apply the composition uniformly, and a known application method can be applied.

[0103] 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 for wrapping films or marking films 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.

[0104] Examples of a method for forming an uneven shape on one surface of a resin substrate include a method of embossing one or both surfaces of the resin substrate.

[0105] When the resin substrate is integrally formed with the concave-convex structure, the material of the resin substrate may be, for example, a thermoplastic resin, which may be appropriately selected from general-purpose plastics and engineering plastics. Among them, vinyl chloride resin is preferred from the viewpoints of weather resistance and abrasion resistance.

[0106] Furthermore, the resin substrate may contain additives such as plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, UV absorbers, antioxidants, antistatic agents, flame retardants, etc. When the resin substrate is integrally formed with the uneven structure and contains a UV absorber, weather resistance can be improved.

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

[0108] The thickness of the resin substrate is not particularly limited and is appropriately selected depending on the application of the uneven resin film, etc. For example, when the uneven resin film of the present disclosure is used as a wrapping film or a marking film for a moving body such as an automobile, a train, or an airplane, the thickness of the resin substrate can be about 80 μm or more and 350 μm or less.

[0109] 3. Size and shape of the textured resin film The size of the uneven resin film of the present disclosure in a plan view is not particularly limited as long as it can be a uneven resin film having an uneven structure on the surface that can reduce pressure resistance, and is appropriately selected depending on the application, etc. The uneven resin film of the present disclosure may be disposed on the entire surface of an object, or may be disposed on a part of the surface of an object.

[0110] In addition, the shape of the uneven resin film of the present disclosure in a plan view is not particularly limited as long as the uneven resin film has an uneven structure on the surface that can reduce pressure resistance, and may be appropriately selected depending on the application, etc. The shape of the uneven resin film of the present disclosure in a 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] Furthermore, the overall thickness of the uneven resin film of the present disclosure is not particularly limited and may be appropriately selected depending on the application of the uneven resin film, and may be, for example, 35 μm or more and 350 μm or less.

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

[0113] In particular, in the above case, it is more preferable that the uneven resin film is arranged and used so that the boundary between the uneven portion 2 and the flat portion 3 is approximately parallel to the flow direction d3 of the gas F, as shown in Fig. 3(a), for example. That is, in the above case, it is more preferable that the uneven resin film is arranged and used so that the first direction d1 is approximately perpendicular to the flow direction d3 of the gas F, that is, so that the second direction d2 perpendicular to the first direction d1 is approximately parallel to the flow direction d3 of the gas F, as shown in Fig. 3(a), for example. This makes it easier to generate vertical vortices near the boundary between the uneven portion and the flat portion, and prevents flow separation.

[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 either flat or curved.

[0118] The uneven resin film of the present disclosure can reduce the pressure resistance of the gas resistance, but the gas is not particularly limited. The density of the gas is, for example, 0.08 kg / m 3 More than 10kg / m 3 It is preferable that the gas is air.

[0119] B. Laminated film The laminate film in the present disclosure has the above-mentioned uneven resin film.

[0120] Since the laminate film in the present disclosure has the above-mentioned uneven resin film, it can reduce pressure resistance by applying it to the surface of an object, and as a result, energy saving and carbon dioxide reduction can be realized. In addition, the laminate film in the present disclosure can be applied to the surface of an object by, for example, sticking, and can easily impart a gas resistance reduction structure to the surface of the object. In addition, since the laminate film in the present disclosure is in the form of a film, it can be applied to curved surfaces and three-dimensional shapes. Furthermore, the laminate film in the present disclosure can be re-applied or replaced.

[0121] Hereinafter, each component of the laminate film according to the present disclosure will be described.

[0122] 1. Textured resin film The uneven resin film in the present disclosure has been described in detail in the section "A. Uneven Resin Film" above, so a detailed description thereof will be omitted here.

[0123] 2. Other configurations The laminate film of the present disclosure may further have other components in addition to the uneven resin film.

[0124] (1) Adhesive layer The laminate film 20 in the present disclosure may have an adhesive layer 21 on the surface of the uneven resin film 1 opposite to the uneven structure, 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 disposing the adhesive layer on one surface of the uneven resin film, the uneven resin film can be easily attached to the surface of an object.

[0125] The adhesive used in the adhesive layer is appropriately selected depending on the application of the laminated film, and examples thereof include acrylic adhesives, urethane adhesives, silicone adhesives, rubber adhesives, and vinyl ether adhesives.

[0126] The adhesive layer may or may not have removability, but is preferably removably. When the adhesive layer has removability, the laminate film can be reattached to the surface of an object, and when the laminate film is reattached or removed, the laminate film can be peeled off from the object without leaving any adhesive residue.

[0127] The term "removable" refers to the property that, after a laminate film is applied to the surface of an object, it can be easily peeled off without destroying the object and without leaving any adhesive on the surface of the object.

[0128] The adhesive layer may also contain a colorant. By containing a colorant in the adhesive layer, it is possible to impart a shielding property. For example, in a case where a design is applied to the surface of an article, if the adhesive layer contains a colorant and the laminated film further has a printed layer as described below, the laminated film can be attached to the surface of the article to hide the design and to apply a new design.

[0129] The thickness of the adhesive layer is not particularly limited and is appropriately selected according to the application of the laminated film. For example, when the laminated film of the present disclosure is used as a wrapping film or a marking film for a moving body such as an automobile, a train, or an 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 the object may be insufficient.

[0130] Examples of methods for forming the adhesive layer include a method of applying an adhesive composition and a method of attaching an adhesive film.

[0131] A separator may be disposed on the surface of the adhesive layer opposite the uneven resin film.

[0132] (2) Printing layer The laminate film in the present disclosure may have a printed layer on the surface opposite to the concave-convex structure of the concave-convex resin film. By having the printed layer on the laminate film, design properties can be imparted.

[0133] The print layer can display information such as letters, numbers, symbols, pictures, patterns, marks, and the like.

[0134] The method for forming the printed layer may be, for example, directly printing on the resin substrate of the uneven resin film to form the printed layer, or, for example, as shown in FIG. 12(b), printing on a support layer 22 to form a printed layer 23. The printed layer may be arranged in a pattern on the resin substrate or support layer, or may be arranged on the entire surface of the resin substrate or support layer. The printing method is not particularly limited.

[0135] The support layer is not particularly limited as long as it is capable of being printed, and for example, a resin substrate can be used.

[0136] The support layer may also contain a colorant. By containing a colorant in the support layer, it is possible to impart a shielding property. For example, in a case where a design is applied to the surface of an article, if the laminate film has a printed layer and the support layer contains a colorant, the laminate film can be attached to the surface of the article to hide the design and to apply a new design.

[0137] The thickness of the support layer is not particularly limited and is appropriately selected depending on the application of the laminated film, etc.

[0138] In addition, when forming a printed layer by printing on a support layer, for example, as shown in Figure 12 (b), a printed sheet having a support layer 22 and a printed layer 23 arranged on one side of the support layer 22 may be separately prepared, and this printed sheet may be attached to the resin substrate 10 via a second adhesive layer 24, or the printed layer, resin substrate, and resin layer may be formed in that order on the support layer.

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

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

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

[0142] Furthermore, the protective layer may contain additives such as ultraviolet absorbers, antioxidants, plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, antistatic agents, and flame retardants, if necessary. When the protective layer contains an ultraviolet absorber, weather resistance can be improved.

[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 laminated film The size of the laminate film in the present disclosure in a plan view is appropriately selected depending on the application, etc. The laminate film in the present disclosure may be disposed on the entire surface of an object, or may be disposed on a part of the surface of an object.

[0145] The shape of the laminate film in the present disclosure in plan view may be appropriately selected depending on the application, etc., and may be, for example, the same as the shape of the uneven resin film in plan view.

[0146] 4.Applications In the present disclosure, the arrangement of the laminate film relative to the gas flow direction is appropriately set depending on the type of uneven structure possessed by the uneven resin film, and can be the same as the arrangement of the uneven resin film relative to the gas flow direction described above.

[0147] The uses of the laminate film in the present disclosure can be similar to the uses of the above-mentioned uneven resin film.

[0148] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. EXAMPLES

[0149] The present disclosure will be further described below with reference to examples and comparative examples.

[0150] [Examples 1 to 11] First, a print roll ("MPI1105" manufactured by Avery Dennison) having a vinyl chloride resin film, an adhesive layer, and a release paper in this order was used to print a pattern on the vinyl chloride resin film of the print roll to form a print layer. Next, a laminate film ("DOL1460" manufactured by Avery Dennison) having a vinyl chloride resin film, an adhesive layer, and a release paper in this order was used, and the release paper was peeled off from the laminate film, and the laminate film was laminated on the print layer. Next, a UV-curable ink was ejected and cured on the vinyl chloride resin film of the laminate film using a UV inkjet device to form an uneven portion having a plurality of linear convex portions and concave portions. In addition, the uneven portion was formed so that the uneven portion and the flat portion were alternately arranged in a stripe shape, as shown in FIG. 1(a). The dimensions of the uneven portion and the flat portion were as shown in Table 1. In this way, a wrapping film was produced.

[0151] [evaluation] The wrapping films of Examples 1 to 11 were attached to a truck-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) at a wind speed of 25 m / s. A comparative example was prepared by not attaching the wrapping film.

[0152] [Table 1]

[0153] It was confirmed that the Cd value was smaller and the gas resistance was reduced in Examples 1 to 11 compared to the comparative example. 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 were all within the predetermined ranges, so the gas resistance reduction effect was greater than in Examples 8 to 11. [Explanation of symbols]

[0154] 1 … Textured resin film 2 … Uneven part 3 … Flat area 4 … Uneven structure 10 ... Resin substrate 11 ... Convex part 12 … Recess 20...Laminated film 21 … Adhesive layer 23…Printing layer d1 … 1st direction d2…Second direction H1 … Height of uneven part L1 … Length of the uneven part in the second direction W1: Width of the uneven portion in the first direction W2: Width of flat part in the first direction

Claims

1. The surface has an uneven structure capable of reducing pressure resistance, In the concave-convex structure, concave-convex portions having a plurality of convex portions and concave portions and flat portions 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 concave-convex portion in a second direction perpendicular to the first direction is 30 mm or more, A concave-convex resin film, wherein the width of the concave-convex portion and the width of the flat portion in the first direction are 0.2 mm or more and 50 mm or less.

2. The uneven portion has a plurality of the protrusions and recesses that extend linearly along the first direction.

3. The uneven resin film according to claim 2 , wherein the width of the linear recess is from 1 to 12 times the height of the uneven portion.

4. The uneven resin film according to claim 2 or 3, wherein the width of the linear convex portions is from 1 to 2 times the height of the uneven portions.

5. The uneven resin film according to claim 1 , wherein the convex portions of the uneven portion protrude relative to a surface of the flat portion.

6. The uneven resin film according to any one of claims 1 to 5, wherein the uneven resin film has a resin substrate and a resin layer arranged on one side of the resin substrate, and the uneven structure is provided on the surface of the resin layer.

7. The uneven resin film according to claim 1 , wherein the uneven resin film has a resin substrate and the uneven structure is formed on a surface of the resin substrate.

8. A laminated film comprising the uneven resin film according to any one of claims 1 to 7.

9. The laminate film according to claim 8 , further comprising an adhesive layer on a surface of the uneven resin film opposite to the uneven structure.

10. The laminate film according to claim 8 or 9, further comprising a printed layer on a surface of the uneven resin film opposite to the uneven structure.

Images