JP2015189029A - Powder adhesion suppression member - Google Patents

Abstract

Disclosed is a powder adhesion suppressing member capable of suppressing adhesion even with a powder having a small particle diameter. A microprojection structure including a microprojection group in which a plurality of microprojections made of a cured resin composition is arranged in close contact with at least one surface of a base material, and adjacent to each other. The average distance between the microprotrusions is 500 nm or less, and the portion of the material that forms the microprotrusions in a horizontal cross section when the microprotrusions are cut along a horizontal plane perpendicular to the depth direction of the microprotrusions. The cross-sectional area occupancy has a structure that increases gradually and gradually as it approaches the deepest part from the top of the microprotrusions, and the static contact angle of pure water on the surface on the microprotrusion structure side is the θ / 2 method A powder adhesion suppressing member that is 90? [Selection] Figure 1

Description

  The present invention relates to a powder adhesion suppressing member.

  Powders generally have a high cohesive force and may adhere as they come into contact with objects. When the powder adheres and is fixed, it may be difficult to remove the powder, and not only the appearance deteriorates, but the powder adhered to the substrate or the like may cause a failure of the substrate.

Conventionally, methods for imparting water repellency and antistatic properties to the surface have been studied as methods for suppressing adhesion of dust and the like.
For example, in Patent Document 1, as a technique for suppressing adhesion of dirt, gum, pressure-sensitive adhesive sheets, and oil stains, a coating layer made of a crosslinked body in which a fluorine-based resin and a silicone-modified acrylic resin are crosslinked is specified. An adhesion prevention sheet is disclosed.

  Patent Document 2 discloses a specific polyamide-based film in which a layer made of a specific aliphatic polyamide composition is disposed on the outermost layer as a technique that is excellent in antistatic properties and makes it difficult to electrostatically adhere powder, dust, and the like. It is disclosed.

Patent Document 3 includes a binder component, conductive particles, and a fluororesin, the conductive particles are joined together by the binder component, the binder component is in close contact with the base, and the surface of the conductive particles is covered with the fluororesin An antifouling membrane with a surface is disclosed.
According to Patent Document 3, the antifouling film can be formed by mixing the binder component dispersion, the conductive particle dispersion, and the fluororesin dispersion to form a paint, and applying the paint to the ground. It is said that. However, when the antifouling film is formed by applying the paint, it is difficult to control the fine shape to a desired shape. Therefore, it is difficult to form a repetitive structure of fine irregularities as shown in FIG. 1 of Patent Document 3 or to form a film surface in which the surface of the conductive fine particles is covered with a fluororesin.

International Publication No. 2008/84847 Pamphlet JP 2012-61851 A International Publication No. 2012/144121 Pamphlet

  The inventors of the present invention have found that even a surface with water repellency and antistatic properties cannot sufficiently suppress the adhesion of powder having a small particle size.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a powder adhesion suppressing member capable of suppressing adhesion even with a powder having a small particle size.

The powder adhesion suppressing member according to the present invention includes a microprojection structure provided with a microprojection group in which a plurality of microprojections made of a cured resin composition are placed in close contact with at least one surface of a substrate. And the average distance between adjacent microprotrusions is 500 nm or less,
Assuming that the microprojections are cut along a horizontal plane perpendicular to the depth direction of the microprojections, the cross-sectional area occupancy of the material portion forming the microprojections in the horizontal cross section is the deepest from the top of the microprojections. It has a structure that increases gradually and gradually as it approaches the part direction,
The static contact angle of pure water on the surface on the microprojection structure side is 90 ° or more by the θ / 2 method.

  In the powder adhesion suppressing member of the present invention, the surface of the microprojection structure has one or more atoms selected from fluorine atoms and silicon atoms added by chemical vapor treatment, This is preferable because adhesion can be further suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a powder with a small particle size, the powder adhesion suppression member by which adhesion is suppressed can be provided.

FIG. 1 is a schematic cross-sectional view showing an example of a powder adhesion suppressing member according to the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the powder adhesion suppressing member according to the present invention. FIG. 3 is a cross-sectional view (a), a perspective view (b), and a plan view (c) for explaining multi-modal microprotrusions. FIG. 4 is a diagram illustrating an example of a Delaunay diagram. FIG. 5 is a schematic cross-sectional view showing an example of a microprojection structure. FIG. 6 is a perspective view (a) and a plan view (b) of a convex protrusion group constituted by a plurality of minute protrusions. FIG. 7 is a schematic view showing an example of a method for forming a microprojection structure using a roll mold.

Hereinafter, the powder adhesion suppressing member according to the present invention will be described.
In the present invention, the term “adhesion” refers to a state in which two substances are in contact with each other and adhered by intermolecular force.

The powder adhesion suppressing member according to the present invention includes a microprojection structure provided with a microprojection group in which a plurality of microprojections made of a cured resin composition are placed in close contact with at least one surface of a substrate. And the average distance between adjacent microprotrusions is 500 nm or less,
Assuming that the microprojections are cut along a horizontal plane perpendicular to the depth direction of the microprojections, the cross-sectional area occupancy of the material portion forming the microprojections in the horizontal cross section is the deepest from the top of the microprojections. It has a structure that increases gradually and gradually as it approaches the part direction,
The static contact angle of pure water on the surface on the microprojection structure side is 90 ° or more by the θ / 2 method.

  The powder adhesion suppressing member according to the present invention will be described with reference to the drawings. 1 and 2 are schematic cross-sectional views showing an example of a powder adhesion suppressing member according to the present invention. A powder adhesion suppressing member 10 shown in FIG. 1 includes a microprojection group in which a plurality of microprojections 3 made of a cured resin composition are closely arranged on at least one surface of a substrate 1. The protrusion structure 2 is provided, and the average distance d between adjacent minute protrusions is 500 nm or less. And the cross-sectional area occupancy rate of the material portion forming the microprojection in the horizontal cross section when the microprojection is cut along a horizontal plane perpendicular to the depth direction of the microprojection is the top of the microprojection It has a structure that gradually increases gradually as it approaches the deepest part direction. Further, in the powder adhesion suppressing member 10 shown in FIG. 2, the microprojection structure 2 is integrally formed on the surface of the substrate 1.

Since the powder adhesion suppressing member of the present invention has the specific microprojection structure on the surface, adhesion of powder is suppressed.
The action of suppressing the adhesion of powder on the surface of the specific microprojection structure is unclear, but is presumed as follows.
Conventionally, there has been known a method for suppressing adhesion of relatively large objects such as dust by imparting antistatic properties. However, the present inventors have obtained the knowledge that even a surface to which antistatic properties are imparted cannot sufficiently suppress the adhesion of a powder having a small particle diameter of, for example, about 400 nm. As a result of intensive studies, it was found that powders with a small particle size are relatively affected by van der Waals forces as intermolecular forces. Van der Waals force is an agglomeration force generated between electrically neutral atoms and molecules. Therefore, even if antistatic properties are imparted to the surface, it is possible to obtain the effect of suppressing the adhesion of powder with a small particle size. There wasn't.
The powder adhesion suppressing member of the present invention has a microprojection structure including a microprojection group in which a plurality of microprojections are closely arranged, and the average distance between adjacent microprojections is 500 nm or less. Yes, the cross-sectional area occupancy of the material part forming the microprojection in the horizontal cross section when assuming that the microprojection is cut in a horizontal plane perpendicular to the depth direction of the microprojection is from the top of the microprojection to the deepest portion. It has a structure that gradually increases gradually as it approaches. Since the microprojection group is formed by closely arranging a plurality of microprojections, the powder hardly enters between the microprojections. Further, when the powder comes into contact with the surface of the microprojection structure 2 as described above, the contact area is reduced. As a result, the van der Waals force generated between the surface of the microprojection structure 2 and the powder is relatively Becomes smaller. Therefore, even if it is a powder with a small particle size, adhesion is suppressed.
Furthermore, the surface on the microprojection structure side of the present invention has a static contact angle of pure water of 90 ° or more by the θ / 2 method and is hydrophobic. A surface having a large static contact angle generally tends to have a small surface free energy. For this reason, it is presumed that adhesion between the powder and the surface of the microprojection structure through moisture is suppressed.

<Base material>
The substrate used in the present invention can be appropriately selected depending on the application, and may be a flat substrate or a curved substrate, and further formed according to the application. A substrate having a three-dimensional shape may be used.
Examples of the material used for the base material include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins, polyurethane resins, polyethersulfone and polycarbonate, Resins such as polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, cycloolefin copolymer, glass such as soda glass, potassium glass, lead glass, ceramics such as PLZT, inorganic such as quartz and fluorite Examples include materials, metals, paper, wood, and composite materials thereof.
Further, the substrate may be any of those supplied in the form of a roll, those that do not bend enough to be wound, but that are curved by applying a load, and those that do not bend completely. You can choose.
In addition, when it is set as the powder adhesion suppression member by which the microprotrusion structure 2 was integrally formed on the surface of the base material 1 like FIG. 2, the hardened | cured material of the resin composition mentioned later as the base material 1 It is integrally formed.

The structure of the base material used in the present invention is not limited to a structure composed of a single layer, and may have a structure in which a plurality of layers are laminated. When it has the structure by which the several layer was laminated | stacked, the layer of the same composition may be laminated | stacked, and the several layer which has a different composition may be laminated | stacked.
In addition, when the microprojection structure to be described later is formed on a microprojection layer made of a material different from the substrate, the surface performance of the substrate such as adhesion between layers, coating suitability, and surface smoothness is improved. From the above, an intermediate layer may be formed on the substrate.

  The transmittance in the visible light region of the substrate used in the present invention can be appropriately adjusted depending on the application, and is not particularly limited. A transparent substrate of 80% or more can be used, and a translucent substrate or an opaque substrate of less than 80% can also be used. The transmittance can be measured by JIS K7361-1 (Plastic—Testing method for total light transmittance of transparent material).

  What is necessary is just to set the thickness of a base material suitably according to a use. In the case of using a film-like base material, it can be, for example, about 100 μm to 1 mm.

<Microprojection structure>
The microprojection structure includes a microprojection group in which a plurality of microprojections made of a cured product of the resin composition are closely arranged, and the average distance between adjacent microprojections is 500 nm or less. By having such a microprojection structure surface, adhesion is suppressed even with a powder having a small particle size.
The microprojection structure may be formed as a microprojection layer using a material different from the base material 1 as shown in FIG. 1, and is formed integrally with the surface of the base material as shown in FIG. It may be. In addition, although not shown, the microprojection structure may be formed on both surfaces of the base material.

Each microprotrusion constituting the microprotrusion structure is formed so as to be planted on a base material, and the microprotrusion in a horizontal cross section when it is assumed that the microprojection is cut along a horizontal plane perpendicular to the depth direction of the microprotrusion. The cross-sectional area occupancy rate of the material portion forming the slab has a structure in which the microprotrusions gradually and gradually increase from the top of the microprotrusions toward the deepest portion, that is, each microprotrusion tapers. Since the microprojection structure having such a tapered microprojection can reduce the contact area with the powder, the van der Waals force between the microprojection structure and the powder is reduced to reduce the powder. Body adhesion can be suppressed. In addition, since the shape is tapered, there is also an advantage that even if the powder enters between the fine protrusions, it easily comes out.
Specific examples of the shape of such microprojections include those having a vertical cross-sectional shape such as a semicircular shape, a semi-elliptical shape, a triangular shape, a parabolic shape, and a bell shape. The plurality of microprotrusions may have the same shape or different shapes.

Furthermore, it is more preferable that the tops of the microprojections have a curved surface. Having a curved surface at the top means that the top has a curved surface shape such as a spherical shape, a spheroid shape, a rotating paraboloid shape, a bell shape, or a curved surface shape that can approximate these curved surface shapes. Say. In addition, in this invention, a top part is the concept which shows a vertex and its vicinity, and means the range of about 10% of the height H of the microprotrusion mentioned later from the vertex of a microprotrusion.
Since the microprotrusions have a curved surface at the top, the contact area of the powder can be made smaller than that having a flat top, which is excellent in the effect of suppressing the adhesion of powder.

In the present invention, a plurality of minute protrusions are closely arranged in the minute protrusion group. Since the minute protrusions are closely arranged, the powder hardly enters between the minute protrusions, and the adhesion of the powder is suppressed. Closely and in the present invention, or base positions of adjacent microprotrusions are in contact, means that close enough in contact, specifically, when the average value of the diameters of the section of the base position of the microprojections has a R _AVG In addition, R _AVG is preferably 80 to 100% of d _AVG , and more preferably 90 to 100%. The above R _AVG is R if the cross section at the base position of the microprojection is a circle, and if it is not a circle, the maximum and minimum values of the cross section width are obtained, and the average value is R. The average value is obtained.

Further, the microprojection group constituting the microprojection structure may include microprojections having a plurality of vertices (hereinafter sometimes referred to as “multimodal microprojections”). Note that a microprojection having only one vertex may be referred to as a “unimodal microprojection” in comparison with a multimodal microprojection. In addition, each convex portion that forms each vertex related to a multi-peak microprojection or a single-peak microprojection is appropriately referred to as a “peak”.
In the present invention, the contact area of the powder can be further reduced by including multi-peaked microprojections in the group of microprojections, which is preferable from the viewpoint of improving the powder adhesion suppressing effect. Multi-modal micro-projections are relatively thicker than the unimodal micro-protrusions, with the thickness of the hem portion relative to the dimensions near the apexes, and because the external force is distributed and received at more apexes. It is considered that the external force applied to each apex can be reduced and the microprojections made of the resin composition can be hardly damaged. Therefore, by having multi-peaked microprojections, there is also an advantage that mechanical strength and scratch resistance are improved.

FIG. 3 is a cross-sectional view (FIG. 3 (a)), a perspective view (FIG. 3 (b)), and a plan view (FIG. 3 (c)) for explaining the multi-modal microprotrusions. Note that FIG. 3 is a diagram schematically showing for easy understanding, and FIG. 3A is a diagram showing a section taken along a broken line that connects the vertices of continuous microprotrusions. In FIG. 3, the xy direction is the in-plane direction of the substrate 1, and the z direction is the height direction of the microprotrusions. In the microprojection structure 2 shown in FIG. 3A, the unimodal microprojections 3 are, for example, gradually cross-sectional area (surface perpendicular to the height direction (FIG. 3 In FIG. 1, the cross-sectional area when cut along a plane parallel to the XY plane) is reduced, and one vertex is formed. On the other hand, as the multi-peak microprotrusions, for example, a groove g is formed at the tip portion as if a plurality of microprotrusions are combined, and the apex is two (3A), and there are three apexes. (3B), and those having four or more vertices (not shown). The shape of the unimodal microprotrusions 3 can be approximated by a round shape at the top like a paraboloid of revolution or a shape with a sharp apex like a cone. On the other hand, the shape of the multimodal microprotrusions 3A and 3B can be approximated by a shape in which a groove-shaped recess is cut in the vicinity of the top of the single-peak microprotrusion 3 and the top is divided into a plurality of peaks. it can. The shape of the multi-peak microprotrusions 3A and 3B has a plurality of maximal points when the longitudinal cross-sectional shape is cut by a virtual cut surface including a plurality of peaks and including the height direction (Z-axis direction in FIG. 3). The shape is approximated by an algebraic curve Z = a ₂ X ² + a ₄ X ⁴ +... + A _2n X ²ⁿ +.

  The ratio of the number of multimodal microprotrusions in the total microprotrusions existing on the surface of the microprotrusion structure is not particularly limited, but is 10% or more from the viewpoint of further suppressing the adhesion of powder. Is preferable, more preferably 30% or more, still more preferably 50% or more.

In addition, at least a part of the microprojection group constituting the microprojection structure is formed adjacent to the top microprojection and the periphery of the top microprojection, and the height is lower than the top microprojection. You may comprise the group of a group of microprotrusions (it calls a "convex-shaped protrusion group" in this invention) which consists of a some peripheral microprotrusion. By having the aggregate of the fine protrusions, the adhesion of the powder is further suppressed.
FIG. 6 shows a perspective view (FIG. 6 (a)) and a plan view (FIG. 6 (b)) of a convex projection group constituted by a plurality of minute projections. The convex projection group 22 shown in FIG. 6 includes a top microprojection 3C having a relatively high height and a plurality of peripheral microprojections 3D having a relatively low height arranged adjacent to the periphery thereof. FIGS. 6A and 6B are diagrams schematically shown for easy understanding, where the xy direction is the in-plane direction of the substrate, and the z direction is the height of the minute protrusion. Direction.
In the present invention, the top microprotrusion has a relatively higher height than the peripheral microprotrusions, and has a height difference of 10 nm or more, and the height difference is 20 nm or more. Is preferred. In addition, the difference in height is preferably 50 nm or less from the viewpoint of suppressing the feeling of roughness on the surface of the microprojection structure.

  The microprojection structure is not particularly limited, but in view of further suppressing the adhesion of powder, the microprojections arranged around the convex projection group gradually increase as they move away from the top microprojections. It is preferable that they are arranged so as to become lower.

The ratio of the number of the microprojections constituting the convex projection group to the total microprojections present on the surface of the microprojection structure is not particularly limited, but is 10% or more from the viewpoint of exerting the effect. Is preferable, more preferably 30% or more, still more preferably 50% or more.
The convex protrusion group does not include a micro protrusion that is adjacent only to the peripheral micro protrusion and has a height lower than that of the top micro protrusion. Further, when the convex protrusion groups are formed adjacent to each other, the peripheral minute protrusions may be shared by the adjacent convex protrusion groups.
The ratio of the number of the microprojections constituting the convex projection group is, for example, the number of the microprojections out of the number of microprojections whose presence was confirmed by image analysis by observing the surface of the microprojection structure with an SEM or the like. This can be obtained by calculating the ratio of the number of microprojections constituting the group.

In the present invention, the microprojection structure prevents the powder from dropping between the projections and reduces the contact area with the powder. The distance d is referred to as “inter-protrusion distance d”.) The average d _AVG is 500 nm or less. The adjacent minute protrusions related to the distance d between the adjacent protrusions are so-called adjacent minute protrusions, and are protrusions that are in contact with the skirt portions of the minute protrusions that are base portions on the base material side. In the powder adhesion suppressing member according to the present invention, when the microprojections are arranged closely so that a line segment is created so as to sequentially follow the valley portions between the microprojections, each microprojection is surrounded in plan view. A mesh-like pattern formed by connecting a large number of polygonal regions is formed. The adjacent minute protrusions related to the distance d between the adjacent protrusions are protrusions that share a part of the line segments constituting the mesh pattern.
The average distance d _AVG between adjacent adjacent protrusions of the micro protrusions is preferably 400 nm or less, and preferably 50 to 300 nm from the viewpoint of preventing the powder from falling between the protrusions and suppressing the adhesion of the powder. Particularly preferred. In addition, when the powder adhesion suppressing member itself needs to have transparency, the powder adhesion suppressing member is such that the average distance d _AVG between the adjacent adjacent protrusions of the minute protrusions is equal to or less than the shortest wavelength λmin in the visible light band. It is preferable from the point which can reduce reflection of visible light. The shortest wavelength λmin in the visible light band may vary somewhat depending on observation conditions, light intensity (luminance), individual differences, and the like, but is typically λmin = 380 nm. From the viewpoint of ensuring the antireflection property, the average distance d _AVG between the adjacent protrusions of the minute protrusions is preferably 300 nm or less, and more preferably 200 nm or less.

In the powder adhesion suppressing member of the present invention, the height H of the microprojections constituting the microprojection structure and the average value _HAVG of the heights may be set as appropriate. Among these, it is preferable to select the minute protrusion height H so that the aspect ratio of the minute protrusions (average protrusion height H _AVG / average adjacent protrusion interval d _AVG ) is 0.5 to 2.5. It is preferable to select the microprojection height H so that the ratio is 0.8 to 2.1.
The average _{H AVG} height H of the minute projections is preferably at 1μm or less, preferably further 500nm or less, is preferably even more 50～350Nm, particularly preferably 100~250nm .
By setting the aspect ratio to be equal to or higher than the lower limit, the adhesion of the powder is further suppressed. Further, by setting the aspect ratio to be equal to or lower than the lower limit value, it is difficult for the minute protrusions to be bent or collapsed.
Here, the height of the microprotrusions refers to the height of the peak (the highest peak) having the highest height at the top of the microprotrusions. In the case of a single-peak microprojection such as the microprojection 3 in FIG. 3A, the height of the only peak at the top is the height of the microprojection. In the case of a multi-peak microprotrusion such as the microprotrusions 3A and 3B in FIG. 3A, the height of the microprotrusions is the highest peak height among a plurality of peaks sharing the ridge at the top. To do.

Moreover, the microprotrusions may have variations in height. When the height varies, the effect of suppressing the adhesion of powder having a variation in size can be expected more. The variation in the height of the fine protrusion is not particularly limited, but the standard deviation σ _H of the height H of the fine protrusion is preferably 2 to 30% of the average value _HAVG of the protrusion height, and is 5 to 25%. More preferably, it is more preferably 10 to 20%.

In the present invention, the distance d between adjacent protrusions and the height H of the minute protrusions are measured by the following method.
(1) First, an in-plane arrangement of projections (planar shape of the projection arrangement) is detected using an atomic force microscope (AFM) or a scanning electron microscope (SEM).

  (2) Subsequently, a maximum point of the height of each protrusion (hereinafter simply referred to as a maximum point) is detected from the obtained in-plane arrangement. There are various methods for obtaining the maximum point, such as a method of sequentially comparing the planar view shape and the enlarged photograph of the corresponding cross-sectional shape to obtain the maximum point, and a method of obtaining the maximum point by image processing of the plan view enlarged photo. Can be applied.

  (3) Next, a Delaunay diagram with the detected maximum point as a generating point is created. FIG. 4 is a schematic plan view showing an example of a Delaunay diagram. As shown in the example of FIG. 4, the Delaunay diagram is defined such that, when Voronoi division is performed using each local maximum point 41 as a generating point, adjacent generating points are defined as adjacent generating points. This is a net-like figure composed of a triangular aggregate obtained by connecting each other with a line segment 42. Each triangle is called a Delaunay triangle, and a side of each triangle (a line segment connecting adjacent generating points) is called a Delaunay line.

  (4) Next, about 5 to 20 minute projections adjacent to each other from the frequency distribution of the line length of each Delaunay line, that is, an enlarged photograph in plan view of the distance between adjacent maximum points (distance between adjacent projections). , Sample the value of the distance between adjacent protrusions, and clearly deviate from the numerical range obtained by sampling (typically the value for the average distance between adjacent protrusions obtained by sampling) Is excluded, and the frequency distribution is detected.

  Specifically, a fine structure in which a concave portion exists on the top of the protrusion, or a fine structure related to a fine protrusion (multi-modal micro protrusion) in which the top is divided into a plurality of peaks has such a fine structure. From the numerical range in the case of non-protruding microprotrusions (single-peak microprotrusions), the distance between adjacent local maximum points clearly differs greatly. By removing the corresponding data using this feature, only the data of the projection body itself is selected and the frequency distribution is detected. More specifically, for example, about 5 to 20 adjacent single-peaked microprojections are selected from an enlarged photograph of the microprojections (group) in plan view, and the value of the distance between the adjacent maximum points is determined. A value that is clearly out of the numerical range obtained by sampling and sampling (usually data whose value is ½ or less of the average distance between adjacent maximum points obtained by sampling) To detect the frequency distribution.

(5) The frequency distribution of the distance d between adjacent protrusions thus determined is regarded as a normal distribution, and the average value d _AVG and the standard deviation σ _d are determined. In the present invention, the maximum value d _max of the distance d between adjacent protrusions is defined as d _max = d _AVG + 2σ _d and is calculated.

A similar technique is applied to define the height of the protrusion. In this case, a relative height difference of each local maximum point position from a specific reference position is acquired from the local maximum point obtained by the above (2), and is histogrammed. The average value H _AVG of the projection height and the standard deviation σ _H are obtained from the frequency distribution by the histogram. When multi-peak microprojections are included, one microprojection has a plurality of vertices, so that a plurality of data are mixed in the histogram of the projection height H for one projection. Become. Therefore, in this case, the frequency distribution is obtained by adopting the vertex having the highest height from among the plurality of vertices belonging to the same microprotrusion as the protuberance.

  The reference position for measuring the height of the microprojections is the base position of the projection, that is, the valley bottom (minimum point of height) between the adjacent microprojections is used as the reference for the height 0. However, when the height of the valley bottom itself varies depending on the location, for example, when the envelope surface connecting the valley bottoms between the microprojections has a concavo-convex shape with a large period compared to the distance between adjacent projections of the microprojections ( (1) First, an area that is sufficient to converge the average value of the heights of the valley bottoms measured from the surface opposite to the surface of the microprojections 31 of the microprojection structure 30. Calculate in (2) Next, a surface having the average height and parallel to the surface opposite to the microprojection surface 31 of the microprojection structure 30 is considered as a reference plane. (3) Then, the height of each microprotrusion from the reference plane is calculated by setting the reference plane to 0 again.

When the height of the valley between the adjacent microprotrusions 32 varies depending on the location, for example, the periodic undulation as shown in FIG. 5 occurs on a plane parallel to the front and back surfaces of the transparent substrate (XY plane in FIG. 5). The height may be constant in only one direction (for example, the X direction) and in a direction perpendicular to the direction (for example, the Y direction), or in a plane (XY plane in FIG. 5) parallel to the front and back surfaces of the transparent substrate. Both directions (X direction and Y direction) may have undulations.
In order to ensure good smoothness of the powder adhesion suppressing member, the height difference (h in FIG. 5) of the concavo-convex surface 33 undulated in the period D is preferably 10 nm or less, and ranges from 1 nm to 5 nm. More preferably, it is within. In addition, the height difference of the uneven surface formed by the uneven surface 33 can be obtained by measuring the height difference of the position of the valley bottom portion of the minute protrusion 32 separated by, for example, 500 nm or more. The position of the bottom of the valley of the fine protrusion 32 can be obtained by observing the antireflection article 10 using a TEM photograph or SEM photograph of a vertical section cut in the thickness direction.

  What is necessary is just to adjust the thickness (T in FIG. 1 or FIG. 2) of a fine uneven | corrugated layer suitably. For example, in the case where the fine uneven layer is provided on the one surface side of the substrate, the thickness of the fine uneven layer is preferably 3 μm to 30 μm, and more preferably 5 μm to 10 μm. Moreover, when the microprojection structure is integrally formed on the surface of the base material, the thickness of the fine uneven layer depends on the thickness of the base material and is not particularly limited. In addition, the thickness T of the fine concavo-convex layer in FIG. 1 is defined by the thickness from the interface of the fine concavo-convex layer to the base material to the top of the highest fine protrusion.

In the powder adhesion suppressing member of the present invention, the static contact angle of pure water on the surface of the microprojection structure is 90 ° or more by the θ / 2 method, so that the surface free energy is small and the powder adhesion is suppressed. Even if the powder adheres, it tends to fall off. In the present invention, among others, the static contact angle of pure water on the surface of the microprojection structure is preferably 90 ° to 170 °, and more preferably 100 ° to 165 °.
In the present invention, the static contact angle is a straight line connecting the left and right end points of the dropped liquid and the apex 1 second after the dropping of 1.0 μL of pure water or n-hexadecane on the surface of the measurement object. The contact angle measured in accordance with the θ / 2 method for calculating the contact angle from the angle to the solid surface. As the measuring device, for example, a contact angle meter DM 500 manufactured by Kyowa Interface Science Co., Ltd. can be used.
The static contact angle can be adjusted by changing the type of material forming the surface of the microprojection structure and the uneven shape of the microprojection structure.

  In the present invention, the microprojection structure is made of a cured product of the resin composition. In addition, in this invention, hardened | cured material means what solidified through or without passing through a chemical reaction. Moreover, in this invention, resin is the concept containing a polymer other than a monomer and an oligomer.

In the present invention, the resin composition suitably used for forming the microprojection structure contains at least a resin and, if necessary, other components such as a polymerization initiator.
The resin is not particularly limited, for example, ionizing radiation curable resins such as acrylate, epoxy, and polyester, acrylate, urethane, epoxy, polysiloxane, and other thermosetting resins, acrylate, Various materials such as polyester-based, polycarbonate-based, polyethylene-based, polypropylene-based thermoplastic resins, and various curing resins for shaping can be used. Moreover, you may contain a non-reactive polymer. The ionizing radiation means electromagnetic waves or charged particles having energy that can be cured by polymerizing molecules. For example, all ultraviolet rays (UV-A, UV-B, UV-C), visible rays, gamma rays , X-rays, electron beams and the like.
As the resin, an ionizing radiation curable resin is preferable because it is excellent in moldability and mechanical strength. The ionizing radiation curable resin used in the present invention is a mixture of a monomer or a polymer having radically polymerizable and / or cationically polymerizable bonds in a molecule as appropriate, and ionized using a suitable polymerization initiator. It is cured by radiation. Further, in the present invention, being excellent in moldability means that it can be accurately molded into a desired shape.
Among them, the resin composition used in the present invention preferably contains at least one selected from the group consisting of acrylate-based, epoxy-based, and polyester-based ionizing radiation curable resins, and further includes an acryloyl group and / or a methacryloyl group. It is preferable to contain at least one selected from acrylate-based ionizing radiation curable resins.

The resin composition used in the present invention may further comprise a polymerization initiator, a release agent, a photosensitizer, an antioxidant, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, and a viscosity adjustment as necessary. An agent, an adhesion improver, etc. can also be contained.
Moreover, you may contain a well-known fluorine containing compound or a silicon containing compound from the point which provides hydrophobicity to the surface by the side of a microprotrusion structure.

  Especially, it is preferable to have 1 or more types of atoms selected from the fluorine atom and silicon atom which were added by the chemical vapor phase process on the surface of the said microprotrusion structure. By adding fluorine atoms or silicon atoms by chemical vapor treatment, fluorine atoms or silicon atoms can be added to the surface of the microprojection structure without impairing the shape of the microprojection structure. By having one or more atoms selected from fluorine atoms and silicon atoms on the surface of the microprojection structure, the hydrophobicity of the surface is increased, and the static contact angle of pure water on the surface on the microprojection structure side is θ In addition to being easily adjusted to 90 ° or more by the / 2 method, the surface free energy is reduced and the adhesion of powder is further suppressed.

The chemical vapor phase treatment used in the present invention is a conventionally known process that can add one or more atoms selected from fluorine atoms and silicon atoms to the surface of a microprojection structure made of a cured product of a resin composition. It can be appropriately selected from chemical vapor processing. As an aspect which has 1 or more types of atoms selected from the fluorine atom and silicon atom which were added to the surface of the said microprotrusion structure by chemical vapor processing, for example, chemical vapor processing is carried out on the surface of the said microprotrusion structure And a mode having a fluorine-containing compound or a silicon-containing compound deposited on the surface of the microprojection structure by chemical modification by chemical vapor treatment.
When a fluorine-containing compound or a silicon-containing compound is added to the surface of the microprojection structure by a solution coating method, the uneven shape on the surface of the microprojection structure is impaired, and the powder adhesion suppressing effect is impaired. On the other hand, according to the method of adding fluorine atoms or silicon atoms to the surface of the microprojection structure by chemical vapor processing, the pure water is static without impairing the irregular shape of the surface of the microprojection structure. The contact angle can be increased. That is, according to the chemical vapor phase treatment, the surface of the microprojection structure can be provided by following the irregularities on the surface of the microprojection structure, whether it is a deposited film or a surface chemical modification. Does not impair the uneven shape. Therefore, when the surface of the microprojection structure has one or more atoms selected from fluorine atoms and silicon atoms added by chemical vapor treatment, the powder adhesion suppressing effect can be enhanced. .
In addition, the specific method of chemical vapor processing is described in detail in the manufacturing method of the microprotrusion structure mentioned later.

(Manufacturing method of microprojection structure)
In the present invention, the method for producing the microprojection structure is not particularly limited, but a method for forming the microprojection structure by shaping on at least one surface of the substrate from the viewpoint of excellent moldability and stable mass production. preferable.
The microprojection structure may be shaped on the surface of another layer made of a material different from the base material provided on the base material, or the base material is made of a shapeable material such as a resin composition. When it becomes, you may shape directly on the said base-material surface.

Examples of the method for producing the microprojection structure include the following methods. That is, first, the resin composition is applied onto a substrate to form a coating film, and the uneven shape of the microprojection structure forming original plate having a desired uneven shape is formed into a coating film of the resin composition. Thereafter, the resin composition is cured to form a microprojection structure, and the original plate for forming the microprojection structure is peeled off.
The concave / convex shape of the original plate for forming a microprojection structure is a shape in which a large number of micropores are densely formed and corresponds to the shape of a group of microprojections provided in the microprojection structure.
Moreover, the method of shaping the concave / convex shape of the original plate for forming a microprojection structure into a resin composition and curing the resin composition can be appropriately selected according to the type of the resin composition.

The original plate for forming the microprojection structure is not particularly limited as long as it is not deformed and worn when repeatedly used, and may be made of metal or resin, Usually, metal is preferably used because it is excellent in deformation resistance and wear resistance.
The surface having the concavo-convex shape of the original plate for forming a microprojection structure is not particularly limited, but is preferably made of aluminum from the viewpoint of being easily oxidized and easily processed by anodization.
Specifically, the original plate for forming the microprojection structure has high purity by sputtering or the like directly on the surface of a metal base material such as stainless steel, copper, or aluminum, or through various intermediate layers. An aluminum layer is provided, and the aluminum layer is formed with an uneven shape. Prior to providing the aluminum layer, the surface of the base material may be made into a super mirror surface by an electrolytic composite polishing method in which electrolytic elution action and abrasion action by abrasive grains are combined.
Examples of a method for forming a concavo-convex shape on the original plate for forming a microprojection structure include, for example, an anodic oxidation step of forming a plurality of micropores on the surface of the aluminum layer by an anodic oxidation method, and etching the aluminum layer. A first etching step for forming a tapered shape in the opening of the microhole, and a second for enlarging the hole diameter of the microhole by etching the aluminum layer at an etching rate higher than the etching rate of the first etching step. It can be formed by sequentially repeating the etching process.
When forming an uneven shape on the original plate for forming a microprojection structure, the purity (impurity amount), crystal grain size, anodizing treatment and / or etching treatment conditions of the aluminum layer are appropriately adjusted to obtain a desired shape. It can be a shape. In the anodic oxidation treatment, more specifically, the micropores can be produced to the desired depth and shape by managing the liquid temperature, the applied voltage, the time for the anodic oxidation, and the like.

Moreover, examples of the shape of the original plate for forming a microprojection structure include a flat plate shape and a roll shape, and are not particularly limited, but a roll shape is preferable from the viewpoint of improving productivity. In the present invention, it is preferable to use a roll-shaped mold (hereinafter sometimes referred to as “roll mold”) as the original plate for forming the microprojection structure.
As the roll mold, for example, as described above, a cylindrical metal material is used as a base material, and the aluminum layer provided on the peripheral side surface of the base material directly or through various intermediate layers, as described above. In other words, the concavo-convex shape is produced by repeating the anodizing treatment and the etching treatment.

  In FIG. 7, the powder adhesion suppressing member of the present invention is manufactured using an ultraviolet curable resin composition as a resin composition for forming a microprojection structure and using a roll mold as an original plate for forming the microprojection structure. An example of the method is shown. In this manufacturing method, first, in the resin supplying step, an uncured and liquid ultraviolet curable resin that constitutes the receiving layer 2 ′ on which the microprojection structure 2 is formed on the substrate 1 in the form of a strip film by the die 31. Apply the composition. In addition, about application | coating of an ultraviolet curable resin composition, not only the case by the die | dye 11 but various methods are applicable. Subsequently, the pressing roller 13 presses and presses the base material 1 against the peripheral side surface of the roll mold 12 which is a shaping mold, thereby bringing the uncured receiving layer 2 ′ into close contact with the base material 1, The concave and convex portions formed on the peripheral side surface of the roll mold 12 are sufficiently filled with the ultraviolet curable resin composition constituting the receiving layer 2 ′. In this state, the ultraviolet curable resin composition is cured by irradiation with ultraviolet rays, whereby the microprojection layer 2 having the microprojection structure is formed on the surface of the substrate 1. Subsequently, the base material 1 is peeled from the roll mold 12 through the peeling roller 14 together with the hard microprojection layer 2. If necessary, an adhesive layer or the like is laminated on the substrate 1 and then cut into a desired size. Thereby, the microprojection structure of a desired shape is efficiently mass-produced.

In order to mix multi-peak microprojections and monomodal micro-protrusions, it must be realized by varying the micro-hole intervals of the micro-projection structure forming original plate produced in the anodizing process. Can do. Multi-modal microprotrusions are created by micropores having a concave portion corresponding to the top of the microprotrusions, and such micropores are produced by etching processing. It is thought that they are formed integrally.
In order to make at least a part of the microprojection structure into the convex projection group described above, it is essential that the height of each microprotrusion has a predetermined range. The variation in the height of each microprojection is due to the variation in the depth of the microhole formed in the original plate for forming the microprojection structure. It can be said that it is caused by variation. In this way, a mixture of a relatively high top microprojection and a plurality of relatively low peripheral microprojections can be realized by increasing the variation in anodizing treatment.

  Further, in the above-described embodiment, the case where the forming method of the microprojection structure is produced on the film-shaped base material by the shaping process using the roll mold is described. Depending on the shape of the material, for example, when forming a microprojection structure by processing a flat plate or a single wafer using a mold for shaping with a specific curved surface shape, It can be appropriately changed according to the shape of the material.

If necessary, it is preferable to add one or more kinds of atoms selected from fluorine atoms and silicon atoms by performing chemical vapor treatment on the surface of the microprojection structure obtained as described above. In the present invention, the chemical vapor treatment method is a conventionally known method capable of adding one or more kinds of atoms selected from fluorine atoms and silicon atoms to the surface of a microprojection structure made of a cured product of a resin composition. Can be selected as appropriate.
In the present invention, the chemical vapor deposition method is preferably a chemical vapor deposition (CVD) method or a reactive ion etching method. Hereinafter, each chemical vapor processing method will be described.

(Chemical vapor deposition (CVD) method)
In the present invention, the CVD method can be appropriately selected from conventionally known methods. Specifically, for example, a thermal CVD method, a photo CVD method, a plasma CVD method, an epitaxial CVD method, an atomic layer CVD method, a metal organic chemical vapor deposition method, and the like can be mentioned. The method is preferably used.

  Specifically, for example, the microprojection structure is obtained by evaporating at least one fluorine-containing compound by heating, mixing it with an inert gas such as argon gas or helium gas as a carrier gas, and converting the gas into plasma. A fluorine-containing compound or a silicon-containing compound can be added to the surface of the body.

As the fluorine-containing compound, a conventionally known compound applicable to the CVD method can be used. Among them, at least one terminal contains a perfluoroalkyl group having 1 to 6 carbon atoms and contains an oxygen atom. It is preferable to use a fluorine-containing compound having 10 or less carbon atoms. Specifically, for example, perfluoroalkanes such as tetrafluoromethane, perfluoroethane, perfluoropropane, perfluorobutane, perfluoropentane, and perfluorohexane, hexafluoropropylene, perfluoro (4-methyl-2-pentene). ), Perfluoroalkenes such as perfluoro (2-methyl-2-pentene) and perfluoro-1-hexene. In the present invention, a fluorine-containing compound having a perfluoroalkyl group having 3 to 6 carbon atoms is preferable from the viewpoint of making the surface of the microprojection structure hydrophobic, and further, the number of carbon atoms is 4 to 6 The perfluoroalkyl group is more preferable. In addition, the fluorine-containing compound preferably contains an unsaturated hydrocarbon group or an iodo group in which active species such as ions and radicals are easily generated.
Moreover, what is necessary is just to select suitably from the conventionally well-known silicon-containing compound applicable to CVD method as said silicon-containing compound. Specific examples include hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), hexamethyldisilazane (HMDS), and octamethylcyclotetrasiloxane.
The mixing ratio of the fluorine-containing compound and silicon-containing compound gas to the inert gas is not particularly limited, but is preferably 1:99 to 30:70 (volume ratio), and 2:98 to 10:90. (Volume ratio) is more preferable.

(Reactive ion etching method)
In the present invention, one or more atoms selected from fluorine atoms and silicon atoms may be added using a reactive ion etching method. In the reactive ion etching method, usually, addition of one or more kinds of atoms selected from fluorine atoms and silicon atoms and etching of the substrate surface are simultaneously performed. In the present invention, fluorine atoms and silicon atoms are used. The purpose is to add one or more selected atoms, and the condition is set so that the surface of the microprojection structure is not etched or does not affect the surface shape even if it is etched.

In the present invention, the reactive ion etching method uses one or more gaseous compounds selected from fluorine-containing compounds and silicon-containing compounds, and adds a fluorine-containing compound to the surface of the microprojection structure by plasma. .
In the reactive ion etching method, oxygen may be further mixed with the gaseous compound. The mixing ratio of one or more gaseous compounds selected from fluorine-containing compounds and silicon-containing compounds and oxygen is preferably 100: 0 to 80:20 (volume ratio), and 100: 0 to 85: More preferably, it is 15 (volume ratio). When the proportion of oxygen is increased, the surface of the microprojection structure may be etched.

As the fluorine-containing compound, a fluorinated alkyl compound is preferably used. Specific examples thereof include tetrafluoromethane, trifluoromethane, hexafluoroethane, and the like. Among these, tetrafluoromethane is preferably used from the viewpoint of making the surface of the microprojection structure hydrophobic.
Examples of the silicon-containing compound include hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), hexamethyldisilazane (HMDS), and octamethylcyclotetrasiloxane.

  When a chemical vapor deposition (CVD) method or a reactive ion etching method is used, a fluorine-containing compound is deposited on the surface of the microprojection structure. Even in this case, the outermost surface of the microprojection structure has an uneven shape due to the uneven shape of the microprojection structure, and is selected from fluorine atoms and silicon atoms added by chemical vapor processing. The film thickness of the portion including one or more kinds of atoms is appropriately selected so that the outermost surface of the microprojection structure has an uneven shape due to the uneven shape of the microprojection structure. For example, when a chemical vapor deposition (CVD) method or a reactive ion etching method is used, the film thickness of the portion containing fluorine atoms is preferably 5 nm to 50 nm, and preferably 10 nm to 40 nm. More preferred.

<Other configurations>
The powder adhesion suppressing member of the present invention is stored, transported, traded, post-processed or constructed in a state in which a peelable protective film is temporarily bonded to the surface of the microprojection structure, and the protective film is peeled and removed in a timely manner. It can also be set as the form to do. Thereby, damage and contamination of the surface of the microprojection structure during storage, transportation, etc. can be prevented.

In addition, the powder adhesion suppressing member of the present invention can form an adhesive layer or an adhesive layer on a surface that does not have a microprojection structure, and can peel a release film on the surface of the adhesive layer or adhesive layer as necessary. An adhesive (adhesion) processed product formed by laminating can be used.
The pressure-sensitive adhesive layer or adhesive used for the pressure-sensitive adhesive layer (adhesive layer) may be appropriately selected from conventionally known pressure sensitive adhesives (pressure-sensitive adhesives), two-part curable adhesives, ultraviolet curable adhesives, Any adhesive form such as a thermosetting adhesive or a hot melt adhesive can be suitably used.
Moreover, what is necessary is just to select suitably from a conventionally well-known thing as a release film. Specific examples of the release film include acrylic resin, polyester resin, polyvinyl chloride resin, cellulose resin, silicone resin, chlorinated rubber, and casein.

<Use of powder adhesion control member>
The powder adhesion suppressing member of the present invention can be used for any application that requires suppression of powder adhesion. The powder adhesion suppressing member of the present invention has an effect of suppressing adhesion regardless of the particle diameter of the powder, and among these, it can be suitably used for powder having a particle diameter of 0.1 to 30 μm. The powder having a particle diameter of 1 to 25 μm can be preferably used.
The powder adhesion suppressing member of the present invention includes any powder of inorganic powder such as titanium oxide, iron oxide, zinc oxide, aluminum hydroxide, boron nitride, talc, mica and silica, and organic powder such as various polymers. The adhesion of the body can also be suppressed, and among these, the adhesion of the powder containing a metal oxide such as titanium oxide, iron oxide, or zinc oxide can be preferably suppressed. Specific examples of the powder containing a metal oxide include cosmetics such as powder foundation, face powder, blusher, and eye shadow, powder blasting agent, and chalk.
The powder adhesion suppressing member of the present invention is, for example, a clean room using powder, wallpaper for interiors such as cosmetics, food production, hospital rooms, ceiling materials, floor materials, air conditioning ducts, nozzles; food processing devices, etc. Various device exteriors and interiors; mirrors, cooking tables, cooking utensils, makeup tools, containers, desks, blackboard edges and receiving parts using chalk, etc.

  Hereinafter, it demonstrates more concretely using an Example. In addition, this invention is not limited to an Example.

(Preparation of resin composition A)
The following components were mixed to prepare a resin composition A for forming a microprojection structure.
-EO-modified bisphenol A diacrylate 70 parts by mass-Polyethylene glycol diacrylate 30 parts by mass-Diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide (Lucillin TPO) 1 part by mass

(Preparation of resin composition B)
The following components were mixed to prepare a resin composition B for forming a microprojection structure.
-EO-modified bisphenol A diacrylate 50 parts by mass-EO-modified trimethylolpropane acrylate 30 parts by mass-tridecyl acrylate 5 parts by mass-dodecyl acrylate 5 parts by mass-methyl methacrylate 5 parts by mass-hexyl methacrylate 5 parts by mass-diphenyl (2, 4,6-trimethoxybenzoyl) phosphine oxide (Lucillin TPO) 1 part by mass

(Preparation of comparative resin composition C)
The following components were mixed to prepare a comparative resin composition C for forming a microprojection structure.
-EO-modified bisphenol A diacrylate 70 parts by mass-Polyethylene glycol diacrylate 30 parts by mass-Diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide (Lucirin TPO) 1 part by weight-Silica gel 5 parts by mass

(Production of mold 1)
The polished aluminum plate having a purity of 99.50% was polished and then anodized in an electrolyte solution of 0.02 M oxalic acid aqueous solution at an applied voltage of 40 V and 20 ° C. for 100 seconds. Next, as a first etching process, an etching process was performed for 50 seconds with the electrolytic solution after anodization. Subsequently, as the second etching treatment, a pore size treatment was performed for 120 seconds with a 1.0 M phosphoric acid aqueous solution. Furthermore, the said process was repeated and these were added and implemented 5 times in total. As a result, an anodized aluminum layer having minute holes formed densely on the aluminum substrate was formed. Finally, a mold release agent for forming a microprojection structure was obtained by applying a fluorine-based release agent and washing away the excess release agent. In addition, the fine uneven | corrugated shape formed in the aluminum layer of the metal mold | die 1 was the average distance between adjacent micropores of 100 nm, and the average depth of 160 nm. In addition, a part of the microholes that become a microprotrusion having a plurality of vertices exist, and some of the microholes have a variation in depth.

(Production of mold 2)
Except that the first etching treatment time was 60 seconds, the second etching treatment time was 130 seconds, and the repeating operation was additionally performed seven times, the average distance between adjacent micro-holes was 200 nm, the average A mold 2 for forming a microprojection structure having a depth of 160 nm was obtained. Note that the fine uneven shape formed on the aluminum layer of the mold 2 has a part of micro holes that become micro projections having a plurality of apexes, and some micro holes have variations in depth. It was a shape.

(Production of mold 3)
Except that the first etching treatment time was 70 seconds, the second etching treatment time was 170 seconds, and the repeating operation was additionally performed five times, in the same manner as in the fabrication of the mold 1, the average distance between adjacent micropores was 400 nm, the average A mold 3 for forming a microprojection structure having a depth of 210 nm was obtained. Note that the fine uneven shape formed in the aluminum layer of the mold 3 has a part of micro holes that become micro projections having a plurality of vertices, and some micro holes have variations in depth. It was a shape.

(Production of mold 4)
Except that the first etching treatment time was 70 seconds, the second etching treatment time was 170 seconds, and the repeating operation was additionally performed seven times, the average distance between adjacent micropores was 500 nm and the average was the same as in the manufacture of the mold 1. A mold 4 for forming a microprojection structure having a depth of 230 nm was obtained. In addition, the fine uneven shape formed in the aluminum layer of the mold 4 has a part of micro holes which become micro protrusions having a plurality of apexes, and some micro holes have variations in depth. It was a shape.

<Chemical vapor phase processing method>
As a chemical vapor treatment method for the surface of the microprojection structure, chemical vapor treatment was performed by the following treatment method.

(Chemical vapor phase processing method 1: CVD method)
The CVD method was performed in combination with RF GENERATOR PRF-153B (ANELVA) and processing unit DEA-506 (ANEVAVA) as energy control devices. A base material on which a microprojection structure to be described later was formed was installed on the reaction stage in the processing apparatus, and the degree of vacuum in the reaction chamber was set to 5 × 10 ⁻³ Pa or less.
Hexamethyldisiloxane (HMDSO; manufactured by Tokyo Chemical Industry Co., Ltd.) was put into a stainless steel container and connected to an argon (Ar) gas line. The stainless steel container containing HMDSO was heated on a 50 ° C. warm bath and vaporized to mix with Ar gas and perform the treatment. At this time, the temperature control and the throttle were adjusted so that the vaporization amount could be mixed 3% with respect to the total Ar flow rate. The mixed gas was flowed at a flow rate of 100 sccm, the internal pressure in the reaction chamber was set to 50 mTorr, and plasma was generated at an energy of 100 W, followed by a CVD process for 3 minutes.
Argon gas having a purity of 99.999% (manufactured by Taiyo Nippon Sanso) was used.

(Chemical vapor phase treatment method 2: reactive ion etching method)
The reactive ion etching method was performed by combining RF GENERATOR PRF-153B (ANELVA) and processing device DEA-506 (ANELVA) as an energy control device in the same manner as the CVD method. A base material on which a microprojection structure to be described later was formed was installed on the reaction stage in the processing apparatus, and the degree of vacuum in the reaction chamber was set to 5 × 10 ⁻³ Pa or less. Next, tetrafluoromethane gas (produced by Showa Denko, purity: 100.00%) was flowed at a flow rate of 100 sccm, the internal pressure in the reaction chamber was changed to 50 mTorr, and plasma was generated at an energy of 100 W, followed by a reactive ion etching treatment for 2 minutes.

[Example 1]
(1) The resin composition A is applied and filled so that the surface having the concavo-convex shape of the mold 1 is covered and the thickness of the microprojection layer on which the microprojection structure is formed is 20 μm after curing, A base material (material: PET, thickness: 25 μm, product name: Lumirror, manufactured by Toray Industries, Inc.) is bonded from an oblique direction on the substrate, and then the bonded body is pressed with a rubber roller under a load of 10 N / cm ^2. did. After confirming that the uniform composition was applied to the entire mold, the resin was cured by irradiating ultraviolet rays with energy of 2000 mJ / cm ² from the substrate side. Then, it peeled from the metal mold | die and obtained the sheet | seat 1 which has a microprotrusion structure.
When the cross section of the surface of the obtained sheet 1 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 100 nm and an average microprojection height of 160 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.
(2) Next, the surface of the microprojection structure of the sheet 1 was processed by the chemical vapor processing method 1 to obtain a sheet-like powder adhesion suppressing member 1.

[Example 2]
(1) In the same manner as in Example 1 except that the resin composition B was used in place of the resin composition A and the mold 2 was used instead of the mold 1 in (1) of Example 1, A sheet 2 having a structure was obtained.
When the cross section of the surface of the obtained sheet 2 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 100 nm and an average microprojection height of 160 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.
(2) Next, the surface of the microprojection structure of the sheet 2 was treated by the chemical vapor treatment method 1 to obtain a sheet-like powder adhesion suppressing member 2.

[Example 3]
(1) A sheet 3 having a microprojection structure was obtained in the same manner as in Example 1 except that the resin composition B was used in place of the resin composition A in (1) of Example 1.
When the cross section of the surface of the obtained sheet 3 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 200 nm and an average microprojection height of 160 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.
(2) Next, the surface of the microprojection structure of the sheet 3 was treated by the chemical vapor treatment method 1 to obtain a sheet-like powder adhesion suppressing member 3.

[Example 4]
(1) A sheet 4 having a microprojection structure was obtained in the same manner as (1) of Example 2.
When the cross section of the surface of the obtained sheet 4 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 100 nm and an average microprojection height of 160 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.
(2) Next, the surface of the microprojection structure of the sheet 4 was treated by the chemical vapor treatment method 2 to obtain a sheet-like powder adhesion suppressing member 4.

[Example 5]
(1) A sheet 5 having a microprojection structure was obtained in the same manner as in Example 3 (1).
When the cross section of the surface of the obtained sheet 5 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 200 nm and an average microprojection height of 160 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.
(2) Next, the surface of the microprojection structure of the sheet 5 was processed by the chemical vapor processing method 2 to obtain a sheet-like powder adhesion suppressing member 5.

[Example 6]
(1) A sheet 6 having a microprojection structure was obtained in the same manner as in Example 1 except that the mold 3 was used instead of the mold 1 in (1) of Example 1.
When the cross section of the surface of the obtained sheet 6 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 400 nm and an average microprojection height of 210 nm was formed. Moreover, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference of standard deviation 25 nm.
(2) Next, the surface of the microprojection structure of the sheet 6 was treated by the chemical vapor treatment method 1 to obtain a sheet-like powder adhesion suppressing member 6.

[Example 7]
(1) In the same manner as in Example 1 except that the resin composition B was used in place of the resin composition A and the mold 3 was used instead of the mold 1 in (1) of Example 1, A sheet 7 having a structure was obtained.
When the cross section of the surface of the obtained sheet 7 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 400 nm and an average microprojection height of 210 nm was formed. Moreover, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference of standard deviation 25 nm.
(2) Next, the surface of the microprojection structure of the sheet 7 was treated in the same manner as in (2) of Example 1 to obtain a sheet-like powder adhesion suppressing member 7.

[Example 8]
(1) A sheet 8 having a microprojection structure was obtained in the same manner as in Example 1 except that the mold 4 was used instead of the mold 1 in (1) of Example 1.
When the cross section of the surface of the obtained sheet 8 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 500 nm and an average microprojection height of 230 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 35 nm.
(2) Next, the surface of the microprojection structure of the sheet 8 was treated in the same manner as in (2) of Example 1 to obtain a sheet-like powder adhesion suppressing member 8.

[Example 9]
(1) In the same manner as in Example 1 except that the resin composition B was used in place of the resin composition A and the mold 4 was used instead of the mold 1 in (1) of Example 1, A sheet 9 having a structure was obtained.
When the cross section of the surface of the obtained sheet 9 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 500 nm and an average microprojection height of 230 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 35 nm.
(2) Next, the surface of the microprojection structure of the sheet 9 was treated in the same manner as in (2) of Example 1 to obtain a sheet-like powder adhesion suppressing member 9.

[Comparative Example 1]
(1) On the substrate (material: PET, thickness: 25 μm, trade name: Lumirror, manufactured by Toray Industries, Inc.), the resin composition A is applied so that the thickness after curing is 20 μm, and the substrate side The resin was cured by irradiating ultraviolet rays with an energy of 2000 mJ / cm ² to obtain a comparative sheet 1 having no microprojection structure.
(2) Next, the cured film surface of the comparative sheet 1 was treated in the same manner as in (2) of Example 1 to obtain a sheet-like comparative powder adhesion suppressing member 1.

[Comparative Example 2]
(1) In Comparative Example 1, Comparative Sheet 2 was obtained in the same manner as Comparative Example 1 except that Resin Composition B was used instead of Resin Composition A.
(2) Next, the cured film surface of the comparative sheet 2 was treated in the same manner as in (2) of Example 1 to obtain a sheet-like comparative powder adhesion suppressing member 2.

[Comparative Example 3]
First, the anti-glare film which has an uneven | corrugated shape on the surface was produced by hardening the comparative resin composition C on a 25-micrometer-thick film. Next, the antiglare sheet of Comparative Example 4 is obtained by pasting the antiglare film on a base material (material: PET, thickness: 25 μm, trade name: Lumirror, manufactured by Toray Industries, Inc.) via an adhesive layer. It was.
When the cross section of the surface of the anti-glare sheet of Comparative Example 4 was observed with an SEM, the surface on the anti-glare film side had a minute protrusion with a variation in height within a height range of 10 to 800 nm, and the distance between adjacent minute protrusions. Irregular uneven | corrugated shape with which the average value of the distance of adjacent protrusions is 740 nm was irregularly arrange | positioned in the range of 500 nm-1 micrometer.

<Measurement of contact angle>
The base material side surface of the sheet obtained in each example and comparative example was attached to a black acrylic plate through an adhesive layer, and pure water (on the surface of the microprojection structure opposite to the black acrylic plate) A 1.0 μL droplet of distilled water for liquid chromatography (manufactured by Pure Chemical Co., Ltd.) was dropped, and after 1 second, the contact angle meter DM 500 manufactured by Kyowa Interface Science Co., Ltd. was used according to the θ / 2 method. The static contact angle was measured. The results are shown in Table 1.

<Powder adhesion suppression evaluation>
(1) Preparation of powder The following powders 1 to 3 were each crushed with an agate mortar, and then classified into series through a sieve of 16 mesh (a sieve opening of 1.18 mm), and then the passed powder was 100 mesh. The sieve was passed through a sieve with a sieve opening of 0.150 mm, and the passed powder was further sieved with a sieve of 270 mesh (a sieve opening of 0.053 mm), and the passed powder was collected.
The obtained powders were each dried by heating in an oven at 130 ° C. for 24 hours to obtain test powders 1 to 3.
-Powder 1: Titanium oxide (average primary particle size 0.20 μm, manufactured by Sakai Chemical Industry Co., Ltd., R-310)
-Powder 2: Titanium oxide (average primary particle size 16 nm (X-ray particle size), manufactured by Sakai Chemical Industry Co., Ltd., STR-100N)
Powder 3: Aluminum oxide (average primary particle size 1.0 μm, Showa Denko KK A-43-M)

(2) Powder adhesion test The base material side surface of the sheet obtained in each Example and Comparative Example was fixed on a 50 mm × 50 mm acrylic plate via an adhesive layer, and the fixed sheet was fixed on the acrylic sheet. Cut to the same size as the board. The charge on the surface of each sheet obtained by an ionizer (manufactured by ASONE, SFV-3000) was neutralized.
About 1 g of the test powder was uniformly placed on each of the obtained sheets and weighed. The weighed value here is M ₀ .
The sheet on which the powder was placed was allowed to stand for 3 minutes, and then the sheet was turned over and held for 5 seconds to allow the powder to fall naturally. The sheet was weighed again. Weighed value of the here and M _i.
The mass of the sheet itself is M,
Adhesion rate = (M _i −M) / (M ₀ −M)
Was calculated to evaluate the powder adhesion suppression effect. The results are shown in Table 1.

[Summary of results]
The powder adhesion suppressing members of Examples 1 to 9 having the microprojection structure in which the average value (pitch) between the microprotrusions is 500 nm or less and the static contact angle of pure water on the surface is 90 ° or more, It became clear that adhesion | attachment was suppressed compared with the comparative powder adhesion suppression member of Comparative Examples 1-2 with flat.

DESCRIPTION OF SYMBOLS 1 Base material 2 Microprotrusion structure 2 'Receptive layer 3 Microprotrusion 3A, 3B Multimodal microprotrusion 3C Top microprotrusion 3D Peripheral microprotrusion 10 Powder adhesion suppression member 11 Die 12 Roll die (original)
13 Pressing roller 14 Peeling roller 22 Convex protrusion group 30 Microprotrusion structure 31 Microprotrusion structure surface 32 Microprotrusion 33 Uneven surface due to waviness 41 Local maximum point (base point)
42 line segment (Delaunay line)
43 Microprotrusions

Claims (2)

A microprojection structure having a microprojection group in which a plurality of microprojections made of a cured resin composition is disposed in close contact with at least one surface of a substrate, and between adjacent microprojections The average distance is 500 nm or less,
Assuming that the microprojections are cut along a horizontal plane perpendicular to the depth direction of the microprojections, the cross-sectional area occupancy of the material portion forming the microprojections in the horizontal cross section is the deepest from the top of the microprojections. It has a structure that increases gradually and gradually as it approaches the part direction,
A powder adhesion suppressing member, wherein a static contact angle of pure water on the surface on the microprojection structure side is 90 ° or more by a θ / 2 method.   2. The powder adhesion suppressing member according to claim 1, wherein the surface of the microprojection structure has one or more atoms selected from fluorine atoms and silicon atoms added by chemical vapor treatment.