JP2010231201A - Fine structure, and fine structure molding and automobile component including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine structure having excellent abrasion resistance by which fine structure is not easily broken due to friction from the external, such as rain collision and surface wiping, and to provide a fine structure molding and an automobile component which respectively include the fine structures. <P>SOLUTION: The fine structure is configured by arranging a plurality of fine projections which are two-dimensionally continued at a pitch of 50 μm and less. Each of the fine projections includes a base part and a coat part coating the base part and having an elastic modulus lower than that of the base part. The fine structure molding forms the fine structure at least on one surface of a base material. Further, an automobile component includes the fine structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fine structure having a water repellent function and an antireflection function. More specifically, the fine protrusions formed on the surface of the fine structure are suppressed from being damaged or destroyed by external friction or the like. The present invention relates to a fine structure, a fine structure molded body including the fine structure, and an automotive part.

  A fine structure has a structure with fine protrusions on the surface, and exhibits a water repellent function and an antireflection function. Therefore, by applying a fine structure to various substrate surfaces, light can be applied to the substrate surface. It is possible to provide a function such as an antireflection function and a water repellent function for preventing liquid, particularly water from adhering.

  For example, the fine structure is suitably used for various display devices such as a liquid crystal display and a CRT display in order to provide an antireflection function. In addition, it can be used for various types of window panels such as vehicles, ships, aircraft, etc., and its water-repellent function realizes a window panel that does not require a wiper. Has been. Furthermore, it is expected that dirt such as water stains can be prevented by using the body panel (see, for example, Patent Document 1).

JP 2005-31538 A

  However, in the fine structure described in Patent Document 1, for example, when used in a window panel of a vehicle, the fine structure is easily destroyed due to rain collision or surface cloth wiping. There is a problem that the water repellency is impaired.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to easily destroy the microstructure due to external friction such as rain collision or surface cloth wiping. An object of the present invention is to provide a fine structure excellent in abrasion resistance, a fine structure molded body provided with the fine structure, and an automobile part.

  As a result of intensive studies to achieve the above object, the present inventors have arranged fine protrusions at a predetermined pitch interval or less in a fine structure, and the fine protrusions cover the base and the base, and the base It has been found that the above object can be achieved by having a coating portion having a lower modulus of elasticity, and the present invention has been completed.

  That is, in the microstructure of the present invention, a plurality of fine protrusions are arranged at a pitch of 50 μm or less, and the fine protrusions have a base portion and a covering portion that covers the base portion and has a lower elastic modulus than the base portion. Features.

  Moreover, the microstructure molded body of the present invention is characterized in that the microstructure of the present invention is provided on at least one surface of a substrate. Furthermore, the automotive component of the present invention is characterized by including the microstructure of the present invention.

  According to the present invention, the fine protrusions are arranged at a predetermined pitch interval or less in the fine structure, and the fine protrusions have a base portion and a covering portion that covers the base portion and has a lower elastic modulus than the base portion. Therefore, a fine structure excellent in wear resistance, in which the fine structure is not easily broken due to external collision such as rain collision or surface cloth wiping, a fine structure molded body having the fine structure, and an automobile Parts can be provided.

It is a fragmentary sectional view showing a first embodiment of a microstructure according to the present invention. It is a fragmentary sectional view showing one embodiment of a fine structure fabrication object concerning the present invention. It is a schematic explanatory drawing which shows the microstructure which concerns on 2nd embodiment of this invention. It is a schematic explanatory drawing which shows the microstructure which concerns on 3rd embodiment of this invention.

Hereinafter, the fine structure of the present invention, the fine structure molded body provided with the fine structure, and parts for automobiles will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional view showing a first embodiment of a microstructure according to the present invention, and FIG. 2 is a partial cross-sectional view showing an embodiment of a microstructure molded body according to the present invention. FIG. 3 is a schematic explanatory view showing the fine structure according to the second embodiment of the present invention, and FIG. 4 is a schematic explanatory view showing the fine structure according to the third embodiment of the present invention.
In this specification, “%” for concentration, content, etc. represents mass percentage unless otherwise specified.

(1) Fine structure A fine structure 200 according to the present invention is formed by arranging a plurality of two-dimensionally continuous fine protrusions 100 at a pitch of 50 μm or less. 10 and a covering portion 20 that covers the base portion 10 and has a lower elastic modulus than the base portion 10. Specifically, it is as follows.
A fine structure 200 according to the first embodiment shown in FIG. 1 has a fine protrusion 100 formed in a frustum shape.
As the shape of the fine protrusion 100, a truncated cone shape such as a truncated cone and a truncated pyramid, and a truncated cone shape such as a cone and a pyramid are preferably used. Various shapes such as a shape, a deformed pyramid shape having a side surface formed of a curved surface, a shape with a rounded tip, and a shape inclined from a center line can be used.
In addition, a polygonal shape or a substantially circular shape is preferably used as the bottom shape, but various shapes such as a star shape and an elliptical shape can be used.
In the present embodiment, the fine protrusions 100 are formed on the planar bottom portion 14. However, the present invention is not limited to this embodiment. For example, as shown in FIG. 3, a recess is formed between the fine protrusions 100 on the bottom portion 14. It is also possible to provide 16.
In such an embodiment, as shown in FIG. 3, assuming a surface B ′ passing through the bottoms 16 b, 16 b... Of the recesses 16, 16. The region partitioned by 16b is defined as the bottom surface of the fine protrusion 100. Similarly, in the embodiment in which the root portion 100r of the fine protrusion 100 has a curved surface and it is difficult to clearly define the bottom portion 14 as shown in FIG. 4, the bottoms 100b, 100b between the root portions 100r, 100r. Assuming a plane B ′ that passes through ..., a region defined by the bottom 100b between the root portions 100r surrounding the fine projection 100 in the plane B ′ is defined as the bottom surface of the fine projection. In this way, the bottom surface is determined and used as a reference surface for determining the height (H + T), the center of gravity point, and the circumscribed circle diameter Db of the bottom surface, which will be described later.

  The pitch between the centroid points on the bottom surface of each fine protrusion 100, that is, the distance A shown in FIG. 1 is 50 μm or less. When the distance A exceeds 50 μm, the water repellent function is not effectively exhibited in various window panels using the fine structure. For example, since drizzle water drops are about 50 μm, the water drops enter the gaps between the fine protrusions.

Note that, in a microstructure that provides an antireflection function, the distance A is preferably 380 nm or less. If it exceeds 380 nm, a part of visible light recognizes the structure and diffusion and diffraction occur, so that the light reflectance may increase.
More preferably, the aspect ratio is 1 or more. When the aspect ratio is less than 1, the antireflection effect tends to decrease.
Here, the “aspect ratio” means a value obtained by dividing the height of the fine protrusion by the circumscribed circle diameter of the bottom surface. The circumscribed circle diameter is calculated as the diameter when the bottom shape is circular, the long diameter when it is elliptical, and the diameter of the circle that circumscribes the polygon when it is polygonal.

  When the fine structure satisfies these conditions, the fine protrusions have a size that cannot be recognized by visible light, so that coloring due to light interference is eliminated and the fine structure can be used as a transparent material. Moreover, since the reflection of scenery can be reduced by the antireflection effect, it can be suitably used for window panels of vehicles, ships, aircrafts, and the like. Furthermore, since the gaps between the fine protrusions are elongated and water intrusion due to water droplet collision is suppressed, super water repellency is exhibited such that water droplets such as rain do not adhere at all.

The fine protrusion 100 includes a base portion 10 and a covering portion 20 that covers the base portion and has a lower elastic modulus than the base portion. Preferably, the elastic modulus of the base portion 10 is 50 GPa to 80 GPa, and the elastic modulus of the covering portion 20 is 0.5 GPa to 5 GPa.
By adopting such a configuration, the base 10 suppresses plastic deformation and wear of the fine protrusions caused by external (shear) input. On the other hand, the covering portion 20 is elastically deformed by receiving external (shear) input, and relaxes and disperses the external (shear) input to the base 10.

  If the elastic modulus of the base portion 10 exceeds 80 GPa or the elastic modulus of the covering portion 20 is less than 0.5 GPa, the covering portion may hardly exert the effect of relaxing and dispersing external (shear) input. If the elastic modulus of the base portion 10 is less than 50 GPa or the elastic modulus of the covering portion 20 exceeds 5 GPa, the covering portion cannot be elastically deformed, and even if the covering portion can be elastically deformed, the base portion is plastically deformed. Or it may break.

  In addition, it is preferable that the front-end | tip part film thickness T of the coating | coated part 20 is 20% or less with respect to the height H of the base 10, More preferably, it is 10% or less, Most preferably, it is 5% or less. If it exceeds 20%, the coated part may be easily worn or broken. Moreover, it is preferable that the lower limit of the tip part film thickness T exceeds 1 nm. If it is 1 nm or less, it becomes difficult to coat uniformly, and thus there may be a limitation in production.

  Examples of the material of the base 10 include transparent inorganic materials such as glass, silicic acid oxide, and aluminum oxide, silicon nitride, magnesium oxide, titanium oxide, indium oxide, and the like.

  Examples of the material of the covering portion 20 include non-crosslinked acrylic / polyethylene, polypropylene, polyvinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, polyvinyl chloride, polycarbonate, modified polyphenylene ether, polyphenylene sulfide, polyether ether ketone, liquid crystalline polymer, Examples thereof include thermoplastic resins such as fluororesin, polyarate, polysulfone, polyethersulfone, polyamideimide, polyetherimide, and thermoplastic polyimide, styrene elastomers such as polystyrene, urethane elastomers, gel materials, and the like.

As for the material of the coating | coated part 20, it is preferable that the contact angle with respect to a water droplet is 90 degrees or more, and it is more preferable that it is 100 degrees or more. This is because the water repellent function of the fine structure is more effectively exhibited.
When the contact angle of the material with respect to water droplets is less than 90 °, or when the contact angle is further increased to improve the water repellency, the covering 20 can be surface-treated with a water repellent material.

  This surface treatment method is not particularly limited as long as the fine concavo-convex structure formed by the plurality of fine protrusions 100 is not filled with the water-repellent material. For example, LB method, PVD method, CVD Examples thereof include a method, a self-assembly method, a sputtering method, and a method in which a single molecule diluted with a solvent is applied.

Examples of the water repellent material include CH ₃ — (Si (CH ₃ ) ₂ —O) n—Si (CH ₃ ) ₂ OCH ₃ (n> 13), CH ₃ — (Si (CH ₃ ) ₂ —O). _{n-SiCH 3 (OCH 3)} 2 (n> 13), CH 3 - (Si (CH 3) 2 -O) n-Si (OCH 3) 3 (n> 13), CH 3 - (Si (CH 3 _{) 2 -O) n-Si (} OC 2 H 5) 3 (n> 13), CH 3 - (Si (CH 3) 2 -O) n-Si (CH 3) 2 (CH 2) 3 OCH 2 CH _{(OH) CH 2 NH (CH} 2) 3 Si (OCH 3) 3 (n> 13), (CH 3 - (Si (CH 3) 2 -O) n-Si (CH 3) 2 (CH 2) 3 _{OCH 2 CH (OH) CH 2} ) 2 n (CH 2) 3 Si (OCH 3) 3 (n> 13), CH 3 _{(Si (CH 3) 2 -O} ) n-Si (OH) 3 (n> 13), CH 3 - (Si (CH 3) 2 -O) n-Si (CH 3) 2 Cl (n> 13) _{, CH 3 - (Si (CH} 3) 2 -O) n-Si (CH 3) 2 (CH 2) 2 SiCH 3 Cl 2 (n> 13), CH 3 - (Si (CH 3) 2 -O) n-SiCl ₃ (n> 1 ₃ ), CH _3- (Si (CH ₃ ) ₂ -O) n-Si (OCOCH ₃ ) ₃ (n> 13), CH _3- (Si (CH ₃ ) ₂ -O _{) n-Si (NCO) 3} (n> 13), CH 3 - (Si (CH 3) 2 -O) n-Si (CH 3) 2 (CH 2) 3 O (CH 2) 3 OCONHSi (NCO) _{3 (n> 13), Rf-} (CH 2) 2 - (Si (CH 3) 2 -O) n-Si (CH 3) _{(CH 2) 3 OCH 2 CH} (OH) CH 2 NHSi (OCH 3) 3 (n> 13), (Rf- (CH 2) 2 - (Si (CH 3) 2 -O) n-Si (CH 3 ) ₂ (CH ₂ ) ₃ OCH ₂ CH (OH) CH ₂ ) ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) _{3 and} other silicone compounds.

  In addition, when the microstructure of the present invention is applied to applications such as contact with liquids other than water, for example, viewing window panels such as reactors and distillation towers in various plant devices, lens surfaces of endoscopes, etc. Depending on each application, it is preferable that the contact angle with respect to the contacting liquid is 90 ° or more by surface treatment or the like.

(2) Microstructure Molded Body A microstructure molded body according to an embodiment shown in FIG. 2 includes the above-described microstructure 200 on one surface of a base material 30. Further, when the substrate 30 is transparent, for example, when the substrate 30 is transparent, the microstructure 200 of the present invention can be provided on both the light incident surface and the transmitted light exit surface.

  The method for providing the microstructure of the present invention on the substrate is not particularly limited. For example, the microstructure can be formed directly on the substrate or by applying a material that can be easily molded with the same refractive index as the substrate. Examples include a method of transferring fine protrusions to a thin film.

  Specifically, when the base material is a resin, a base mold having innumerable fine protrusions is prepared, and one or both of the mold and the base film are heated and relatively pressed against each other. As a result, the base portion of the microstructure can be formed on the surface of the base material. Further, the active energy ray is irradiated between the mold and the base film in a state where the active energy ray curable resin is interposed, and the resin is cured, so that the surface of the substrate has the fine structure. A base can be formed.

  When the substrate is an inorganic material, the surface is formed by a method of forming the base of the fine structure by cutting the surface with an electron beam or the like, or a method of pouring a molten inorganic material into a mold having numerous fine protrusions. It is possible to form a microstructured compact having a microstructure base. If necessary, after pouring the molten inorganic material, the second mold having the same fine protrusions is pressed before cooling, or the inorganic material with the mold pressed on both sides is heated to the softening point. By applying pressure and transferring the shape, the base portion of the fine structure can be formed on both surfaces of the substrate.

  After the base is formed by the above-described method, etc., the base after formation is covered by the LB method, the PVD method, the CVD method, the self-assembly method, the sputtering method, or the method of applying a solution obtained by diluting a single molecule with a solvent. By this, the covering portion can be formed.

  When the microstructure of the present invention is incorporated in a base material in a display device, it is most effective to provide it on the forefront. Further, the microstructure of the present invention can be applied to one surface of the base material, and a conventional antireflection method can be applied to the other surface. As a conventional antireflection method, for example, a method of applying an antireflection structure in which fine protrusions are arranged only at a pitch equal to or less than the wavelength of light, a film thickness of an antireflection layer, and a thin film surface and a substrate adhesive surface are controlled. And a method of canceling the reflected light by causing the reflected light to interfere with each other.

(3) Molded product provided with fine structure The molded product provided with the fine structure according to the present invention includes, for example, mobile devices such as automobile and motorcycle meter panels, mobile phones, electronic notebooks, signboards, watches, and other display devices. It is preferably used for a display device that requires an antireflection function at the forefront of the screen and may be exposed to water such as rain or oil stains.

  The format of the display device is not particularly limited, for example, a method that combines mechanical display and illumination such as an analog meter, a method that uses a backlight or light emitting surface such as a liquid crystal, LED, or EL like a digital meter or monitor And a method using a reflective liquid crystal as in mobile devices.

  Since these molded products are mainly used in places exposed to light, in order to prevent deterioration due to light, UV absorbers, antioxidants, radical scavengers, etc. can be added to the material. . Further, a bluing agent or a fluorescent coloring pigment for compensating for yellowing due to deterioration of the resin can be used.

  As described above, the microstructure molded body of the present invention is obtained by forming the above-described microstructure on at least one surface of the base material, so that reflection of light can be suppressed to an extremely low level. . Applying it to various parts including automobiles, such as meter covers and window shields, prevents reflection of outdoor scenery and interiors, and exhibits excellent water repellency. This contributes to the realization of a windshield that does not require a wiper.

  In addition, it is preferable that at least 1 is transparent among the base part and coating | coated part which are contained in a microstructure, and a base material, and, as for a microstructure molded body, it is more preferable that all are transparent. This is because it can be suitably used for various window panels and glass surfaces.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples. In addition, the value of the elastic modulus described below is a value measured by the method described in JIS K6911.

Example 1
A base (elastic modulus: 70 GPa) of a cone having a pitch (A) of 100 nm and a height (H) of 200 nm between the center of gravity of the bottom surface is made of sol-gel glass on both surfaces of the float glass, and the base is covered with PVA. Then, a coating part (elastic modulus: 2 GPa) having a tip film thickness (T) of 5 nm (T / H = 2.5%) was formed to obtain a microstructured body of this example.

(Example 2)
A base (elastic modulus: 75 GPa) of a cone with a pitch (A) of 300 nm and a height (H) of 600 nm between the center of gravity points of the bottom is made of green glass on one side of the green glass, and the base is made of a ring gel. Then, a coated part (elastic modulus: 0.5 GPa) having a tip film thickness (T) of 15 nm (T / H = 2.5%) was formed to obtain a microstructured body of this example.

Example 3
A base (elastic modulus: 65 GPa) of a cone having a pitch (A) of 1000 nm and a height (H) of 1000 nm between the center of gravity of the bottom is made of sol-gel glass on one side of the float glass, and the base is made of acrylic resin (Mitsubishi And coated with Rayon Co., Ltd. to form a coating portion (elastic modulus: 3.5 GPa) having a tip film thickness (T) of 50 nm (T / H = 5%) to obtain a microstructured body of this example. .

Example 4
A base of a cone (elasticity: 65 GPa) having a pitch (A) of 300 nm and a height (H) of 600 nm between the center of gravity of the bottom is made of sol-gel glass on one side of the float glass, and the base is made of acrylic resin (Mitsubishi The coated part (elastic modulus: 3.5 GPa) having a tip film thickness (T) of 10 nm (T / H = 1.7%) was formed by coating with Rayon.
Next, water repellent treatment by sputtering (FAS C8F17, contact angle 116 ° of the material itself) was performed to obtain a microstructured molded body of this example.

(Comparative Example 1)
A base of a cone (elastic modulus: 65 GPa) having a pitch (A) of 100 nm and a height (H) of 200 nm between the center of gravity of the bottom surface on one side of the float glass is made of sol-gel glass. Got.

(Comparative Example 2)
On one side of the float glass, a base (elastic modulus: 65 GPa) of a cone having a pitch (A) of 300 nm and a height (H) of 600 nm between the center of gravity of the bottom is made of sol-gel glass, and then water-repellent treatment by sputtering (FAS C8F17, contact angle 116 ° of the material itself) was performed to obtain a microstructured body of this example.

(Example 5)
A base with a pitch (A) between the center of gravity of the bottom surface (A) of 100 nm and a height (H) of 200 nm on one side of the float glass, a clear apex and a flat surface at the tip, and a bottom with a continuous curve ( (Elastic modulus: 45 GPa) is made of sol-gel glass, and the base is dissolved in acrylic resin “Acrypet” (manufactured by Mitsubishi Rayon Co., Ltd.) at a concentration of 1% with MEK and coated with a wet coat thickness of 300 nm using a spin coater. -It dried and formed the coating | coated part (elastic modulus: 3.5 GPa) with a tip film thickness (T) 3nm.
Next, water repellent treatment by sputtering (FAS C8F17, contact angle 116 ° of the material itself) was performed to obtain a microstructured molded body of this example.

(Example 6)
It was produced in the same manner as in Example 5 except that the pitch (A) between the center of gravity points on the bottom surface was 400 nm, the height (H) was 500 nm, the base portion had an elastic modulus of 51 GPa, and the coating portion had a tip film thickness (T) of 20 nm.

(Example 7)
It was produced in the same manner as in Example 5 except that the pitch (A) between the center of gravity points on the bottom surface was 380 nm, the height (H) was 500 nm, the base was an elastic modulus of 51 GPa, and the tip film thickness (T) was 20 nm.

(Example 8)
A base with a pitch (A) between the center of gravity of the bottom surface (A) of 100 nm and a height (H) of 200 nm on one side of the float glass, a clear apex and a flat surface at the tip, and a bottom with a continuous curve ( (Elastic modulus: 80 GPa) is made of sol-gel glass, the base is dissolved in MMA-lauryl acrylate copolymer at a concentration of 1% with MEK, and coated and dried at a wet film thickness of 500 nm using a spin coater. A coating part (elastic modulus: 3.5 GPa, contact angle: 91 °) having a tip film thickness (T) of 5 nm was formed.

Example 9
A base with a pitch (A) between the center of gravity of the bottom surface (A) of 100 nm and a height (H) of 200 nm on one side of the float glass, a clear apex and a flat surface at the tip, and a bottom with a continuous curve ( (Elastic modulus: 85 GPa) is made of sol-gel glass, the base is dissolved in MMA-hexyl acrylate copolymer at a concentration of 1% with MEK, and coated and dried at a wet film thickness of 500 nm using a spin coater. A coating part (elastic modulus: 3.5 GPa, contact angle: 85 °) having a tip film thickness (T) of 5 nm was formed.

(Example 10)
A base with a pitch (A) between the center of gravity of the bottom surface (A) of 100 nm and a height (H) of 200 nm on one side of the float glass, a clear apex and a flat surface at the tip, and a bottom with a continuous curve ( (Elastic modulus: 85 GPa) is prepared with sol-gel glass, and the base is dissolved in MMA-trifluoromethyl acrylate copolymer at a concentration of 1% with MEK, and coated and dried at a wet film thickness of 500 nm using a spin coater. Then, a coating portion (elastic modulus: 3.5 GPa, contact angle: 100 °) having a tip film thickness (T) of 5 nm was formed.

(Example 11)
A base (elastic modulus: 65 GPa) of a cone having a pitch (A) between the center of gravity of the bottom surface of 100 nm and a height (H) of 200 nm is made of sol-gel glass on one side of the float glass, and the base is GENIOMERSLJ9111 (Asahi Kasei Corporation). The product is dissolved in a butyl acetate-hexane solvent at a concentration of 1%, and coated, dried and cured at a wet film thickness of 1000 nm using a spin coater, and a coated part (elastic modulus: 0) having a tip film thickness (T) of 10 nm. .45 GPa) was formed.

Example 12
A base (elastic modulus: 65 GPa) of a cone having a pitch (A) between the center of gravity of the bottom surface of 200 nm and a height (H) of 600 nm is made of sol-gel glass on one side of the float glass, and the base is GENIOMERSLJ9135 (Asahi Kasei Corporation). The product is dissolved in a butyl acetate-hexane solvent at a concentration of 1%, and coated, dried and cured with a spin coater at a wet film thickness of 1500 nm, and a coating film having a tip film thickness (T) of 15 nm (elastic modulus: 0) .5 GPa) was formed.

(Example 13)
A base (elastic modulus: 65 GPa) of a cone having a pitch (A) between the center of gravity of the bottom surface of 100 nm and a height (H) of 200 nm is made of sol-gel glass on one side of the float glass. (Made by Kasei Co., Ltd.) with an ethyl acetate solvent, dissolved at a concentration of 1% using a spin coater, coated and dried at a wet film thickness of 1000 nm, and then UV-cured in a nitrogen atmosphere to provide a coating with a tip film thickness (T) of 10 nm. Part (elastic modulus: 5.0 GPa) was formed.

(Example 14)
A base (elastic modulus: 65 GPa) of a cone having a pitch (A) between the center of gravity of the bottom surface of 200 nm and a height (H) of 200 nm is made of sol-gel glass on one side of the float glass, and the base is made of diamond beam MP141 ( Mitsubishi Rayon Co., Ltd.) was dissolved in ethyl acetate solvent to a concentration of 1%, coated and dried with a spin coater at a wet film thickness of 1000 nm, and then UV-cured in a nitrogen atmosphere to obtain a tip film thickness (T) of 10 nm. A covering portion (elastic modulus: 5.8 GPa) was formed.

Performance Evaluation Using the fine structure molded bodies of Examples 1 to 14 and Comparative Examples 1 and 2 described above, wear resistance and water repellency were evaluated by the following evaluation methods.

[Abrasion resistance evaluation test method]
After traversing 200 times under the following conditions using a traverse type wear tester, the case where there was no damage by visual inspection was marked with ◯, and the case where there was damage was marked with x.
Friction cloth: canvas cloth (JIS L 3102)
Load: 9.8kPa
Stroke length: 100mm
Friction speed: 30 reciprocations / minute

[Water Repellency Evaluation Test Method]
After carrying out the abrasion resistance evaluation test, the water repellency was evaluated in five stages according to the following criteria using a spray tester (manufactured by Toyo Seiki) based on the method defined in JIS L1092.
1: What wets and spreads over the entire surface 2: What wets and spreads without maintaining a spherical shape on the surface 3: What spherical droplets adhere to the surface 4: What slightly adherent spherical droplets adhere to the surface 5 : No droplets on the surface

Results The results of abrasion resistance evaluation and water repellency evaluation are shown in Tables 1 and 2. In each of the Examples and Comparative Examples, the state of the microstructure after the abrasion resistance evaluation test was observed with an electron microscope. In Comparative Examples 1 and 2, plastic deformation of the fine protrusions was confirmed. At ~ 14, the plastic deformation of the fine protrusions was clearly reduced. Among them, in Examples 1 to 4, 7 to 9, 12, and 13 in which the elastic modulus of the base portion and the covering portion is in a preferable range, the plastic deformation of the fine protrusions was hardly confirmed, and the abrasion resistance evaluation result was particularly good. .

  As mentioned above, although this invention was demonstrated in detail by some embodiment and an Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.

DESCRIPTION OF SYMBOLS 10 Base part 14 Bottom part 16 Recessed part 20 Covering part 30 Base material 100 Fine protrusion 200 Fine structure A Pitch (distance) between the gravity center points of the bottom face of fine protrusion
T Film thickness at the tip of the coating H Height of the base

Claims (7)

A fine structure comprising a plurality of two-dimensionally continuous fine protrusions arranged at a pitch of 50 μm or less,
The fine structure according to claim 1, wherein the fine protrusion has a base portion and a covering portion that covers the base portion and has a lower elastic modulus than the base portion.   The microstructure according to claim 1, wherein the elastic modulus of the base portion is 50 GPa to 80 GPa, and the elastic modulus of the covering portion is 0.5 GPa to 5 GPa.   The microstructure according to claim 1 or 2, wherein a contact angle of the surface of the covering portion with respect to water droplets is 90 ° or more.   The microstructure according to any one of claims 1 to 3, wherein the pitch is 380 nm or less.   A microstructure formed body comprising the microstructure according to any one of claims 1 to 4 on at least one surface of a substrate.   The microstructure molded body according to claim 5, wherein at least one selected from the group consisting of the base portion, the covering portion, and the base material is transparent.   An automotive part comprising the microstructure according to any one of claims 1 to 4.

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