JP2018118466A - Mold having discrete protrusion structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold capable of efficiently molding a functional film such as a microneedle having a large chemical holding amount per unit area and a high shape retention property and a filter having a high opening ratio and a high form accuracy.SOLUTION: A mold of a present invention is a mold having a discrete protrusion structure having protrusions regularly arranged on a surface of a plate. The protrusion is composed of a sharp portion having a pyramidal shape and a prism portion serving as a base of the sharp portion. When a width of the sharp portion is a1, a height of the sharp portion is h1, a pitch of the protrusion is P, a width of the prism portion is a2, and a height of the prism portion is h2, a following expression (i)to(iii) are satisfied. P/a1≤2.5(i), (h1+h2)/a2≥2(ii), h1<h2(iii).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mold having a discrete protrusion structure.

  Currently, functional films having fine irregularities on the surface and functional films having fine through holes are required in the fields of medical products and cosmetics. The functional film having fine irregularities on the surface includes a film having a microneedle (concave) shape for a process paper to which cosmetic components such as collagen are poured and solidified as a microneedle-shaped crystal, or a chemical applied to the needle surface. And a film having a microneedle (convex) shape for administration to the skin. Examples of the film having fine through holes on the surface include filters that perform cell separation and filtration.

  In order to form these functional films, a mold having a fine protrusion structure is often required. For example, when a film having a microneedle (concave) shape is formed, a mold having a discrete protrusion structure corresponding to the inverted microneedle (convex) shape is used, and the film is formed by injection or imprinting. There is a way. In addition, when a film having a microneedle (convex) shape is formed, there is a method in which a mold having a microneedle (concave) shape, which is an inverted shape thereof, is similarly used for injection or imprinting. Here, in order to manufacture a mold having a microneedle (concave) shape, a mold having a discrete protrusion structure corresponding to the reversal of the microneedle (concave) shape, that is, the microneedle (convex) shape to be a product is used. A micro-needle (concave) -shaped mold may be manufactured by performing reverse replication such as electroforming from a mold having a discrete protrusion structure, which is a master mold, as a master mold (for example, Patent Documents) 1 and 2).

 In addition, when a film having fine through holes is formed, there is a method of forming through holes by heating a mold having a discrete protrusion structure and pressing it against a laminated structure (for example, see Patent Document 3). .

  As described above, the formation of a film having a micro uneven shape such as a microneedle is often performed by molding such as injection or imprint using the fluidity of a resin, and molding with high moldability to the mold shape is performed. Done. It is also known that the transferability is high when reverse replication such as electroforming is performed from a mold having a discrete projection structure which is a master mold. That is, in these methods, when a functional film having fine irregularities such as microneedles is formed, the shape of the mold having the original discrete projection structure is an important component that determines the irregular shape of the product.

  In addition, when a functional film having fine through-holes is formed, the shape of the mold having the discrete protrusion structure determines the shape and arrangement of the fine holes because it is performed by molding such as imprint using the fluidity of the resin. In addition to being an important component, the height of the protrusion structure and the shape of the tip are important components that affect the moldability such as the thickness of the product and the quality of penetrability.

  As a method of manufacturing a mold having such a discrete protrusion structure, Patent Document 1 discloses a method of manufacturing a mold having a discrete protrusion structure having a conical or frustum shape by wire cutting from two or more directions. Has been. Further, Patent Document 2 discloses a die that sharpens by sharpening the tip portion by etching into a substantially square frustum shape formed by grooving by cutting or grinding from two directions. A manufacturing method is disclosed.

  Further, Patent Document 3 discloses a die structure having such a discrete protrusion structure, such as a conical shape and a cylindrical connecting structure, and a die structure in which a pyramid shape and a quadrangular prism are combined.

JP-T-2006-513811 JP 2008-114345 A International Publication No. 2014/171365 Pamphlet

  In a mold having a discrete projection structure having a conical or frustum shape as described in Patent Document 1, since the entire projection is a frustum or frustum shape, the bottom of the projection is large, and the projection per unit area It is difficult to make the number sufficiently large. When microneedles are molded using a mold having such a discrete protrusion structure, the bottom of the microneedles is large and the number of microneedles per unit area cannot be sufficiently increased. There was a problem that it was difficult to obtain a sufficient amount of cosmetics or the like.

  Simply, when the discrete protrusion structure has a conical shape with a small bottom area, the protrusion tip is too sharp and it is difficult to obtain sufficient strength as a mold, and the molded microneedle is also sufficient for piercing. There was a problem that it was difficult to obtain strength.

  In addition, since the discrete protrusion structure is formed by wire cutting, a flat portion is likely to be formed at the tip of the protrusion, and when the microneedle is formed with such a mold, the tip is not sharp and sufficient puncture is performed. There was a problem that it was difficult to obtain the properties.

  In a mold having a discrete protrusion structure with a sharpened tip portion of a substantially quadrangular pyramid as described in Patent Document 2, the tip shape is made by etching, and the tip portion shape is not arbitrarily defined, There were problems such as chipping during use. Further, as described in Patent Document 2, it is necessary to perform both machining such as cutting or grinding and etching, and there is a problem that the die manufacturing efficiency is poor because the process is complicated. Further, when the microneedle is molded using a mold having such a discrete protrusion structure, there is a problem that the sharp portion of the tip tends to be lost even in the molded microneedle.

  Although Patent Document 3 discloses a mold structure in which a pyramid shape and a quadrangular prism are combined, its arrangement and detailed shape are not sufficiently clear. When a film having a through hole is formed using such a mold, the separation rate as a filter can be increased as the aperture ratio is higher. However, the mold described in Patent Document 3 is optimized in this respect. It wasn't removed.

A mold having a discrete projection structure according to the present invention for solving the above-mentioned problems is a mold having projections regularly arranged on a plate surface, and the projection has a pointed portion having a pyramid shape and a base of the pointed portion. It consists of a prismatic part that becomes
When the width of the sharp part is a1, the height of the sharp part is h1, the pitch of the protrusion is P, the width of the prism is a2, and the height of the prism is h2, the following formulas (i) to ( It has a discrete protrusion structure characterized by satisfying iii).
P / a1 ≦ 2.5 (i)
(H1 + h2) / a2 ≧ 2 (ii)
h1 <h2 (iii).

Moreover, it is preferable that the metal mold | die which has the discrete protrusion structure of invention has the following characteristics.
-The width | variety a2 of the said prismatic part satisfies the following formula | equation.
a2 ≦ 50 μm.
-The shape of the bottom of the prismatic part is any of three, four, six, and octagon.
The apex of the sharp part has R, and this R satisfies the following formula.
R ≦ a1 / 4

According to the present invention, there is provided a mold having protrusions regularly arranged on a plate surface, the protrusions including a sharp portion having a pyramid shape and a prism portion serving as a base of the sharp portion, the sharp portion. The following formulas (i) to (iii) are satisfied, where a1 is the height, the height of the sharp portion is h1, the pitch of the protrusion is P, the width of the prism is a2, and the height of the prism is h2. By providing a mold having a discrete protrusion structure, a microneedle having a large amount of chemicals to be retained per unit area and having a high shape retaining property, and a filter having a high opening ratio and good shape accuracy The functional film such as can be efficiently formed.
P / a1 ≦ 2.5 (i)
(H1 + h2) / a2 ≧ 2 (ii)
h1 <h2 (iii)

FIGS. 1A and 1B are schematic views for explaining a protrusion of a mold having a discrete protrusion structure according to the present invention. FIG. 1A is a front view and FIG. 1B is a top view. FIG. 2 is a schematic cross-sectional view illustrating details of a mold having a discrete protrusion structure according to the present invention. 3A to 3H schematically illustrate the cross-sectional shape of the protrusion in the mold having the discrete protrusion structure of the present invention. 4A to 4H schematically illustrate the shape of the bottom surface of the prism portion in the mold having the discrete protrusion structure of the present invention. FIG. 5 schematically illustrates the sharp part of the mold having the discrete protrusion structure of the present invention. 6A to 6E schematically illustrate a method for manufacturing a mold having a discrete protrusion structure according to the present invention. FIG. 7 shows a profile of a mold having a discrete protrusion structure obtained in the example.

Embodiments of the present invention will be described below.
FIGS. 1A and 1B are schematic views for explaining a protrusion of a mold having a discrete protrusion structure according to the present invention. FIG. 1A is a front view and FIG. 1B is a top view. The protrusion 20 in the mold 10 having discrete protrusions of the present invention is a structure protruding on the surface of the plate 23. In addition, the protrusion 20 includes a sharp portion 21 having a pyramid shape and a prism portion 22 serving as a base thereof. In this way, by being composed of a sharp portion and a prism portion, it is possible to make a structure having sufficient strength while having puncture properties at the sharp portion, and by making the base a prism portion, individual protrusions And the protrusions can be arranged densely. It is preferable that the protrusions 20 are regularly arranged on the surface of the plate 23. The sharpened portion 21 and the prismatic portion 22 of the protrusions 20 that are arranged may have different shapes, but preferably have the same shape.

  A point at which the distance from the plate surface is maximum in the sharp portion 21 is called a vertex. The pitch P of the protrusions 20 of the mold 10 having the discrete protrusion structure of the present invention refers to an interval taken in the narrowest direction among the repeated intervals of the apexes of the protrusions 20 arranged on the surface of the plate 23, A surface cut parallel to the direction defining the pitch is called a cross section of the protrusion.

  FIG. 2 is a schematic cross-sectional view for explaining details of the discrete protrusion structure in the present invention. FIG. 2 is a cross-sectional view of the protrusion that passes through the apex of the discrete protrusion structure and is cut in parallel to the pitch direction (hereinafter, the section of the protrusion is simply referred to as this section).

  As shown in FIG. 2, the protrusion structure in the present invention has a shape in which the width of the protrusion is gradually or discretely reduced from the plate surface to the apex in the cross section of the protrusion.

  As shown in FIG. 2, the protrusion structure in the present invention is divided into a sharp portion 21 and a prism portion 22 depending on the angle formed by the outline line in the cross section of the protrusion and the perpendicular of the plate surface. A portion including an apex of the discrete protrusion structure and having an angle between the outline of the cross section of the protrusion and the perpendicular of the plate surface is greater than 5 degrees is referred to as a sharp portion 21. Although only two steps are shown in FIG. 2, even in a multi-stage structure of three or more steps, a range including an apex of the discrete protrusion structure and an angle formed between the outline in the cross section of the protrusion and the perpendicular to the plate surface is greater than 5 degrees. This part is defined as a sharp part. In order to ensure the strength of the sharp portion, it is more preferable that the angle formed between the outline of the cross section of the protrusion and the perpendicular of the plate surface including the apex of the discrete protrusion structure is 30 degrees or more and 90 degrees or less. In the case where the inclination of the outline differs between the right and left of the cross section of the projection, the outline on the side having a larger angle with the perpendicular to the plate surface should satisfy this relationship.

  Further, the prism portion 22 is a portion between the sharp portion and the plate surface. The prism portion may be a portion that can be substantially regarded as a prism, and may have a so-called truncated pyramid shape in which the angle formed by the outline of the cross section of the protrusion and the perpendicular of the plate surface is not less than 0 degrees and not more than 5 degrees. Further, even if a part of the prism portion has a portion where the angle between the outline line in the cross section of the protrusion and the perpendicular to the plate surface is 5 degrees or more, the outline line in the cross section of the protrusion and the plate surface in the entire prism portion. If the average value of the angle formed with the vertical line is 5 degrees or less, it may be regarded as a prism portion. In order to arrange the protrusions densely, it is more preferable that the angle formed by the outline of the cross section of the protrusion and the perpendicular of the plate surface is 0 degree or more and 3 degrees or less. It is a particularly preferable aspect that the contour line in the cross-sectional shape of the protrusion has a bending point as shown in FIG. 2 between the prism portion and the sharp portion.

  The width a1 of the sharp portion in the protrusion structure of the present invention refers to the width of the lowermost portion of the sharp portion in the cross section of the protrusion. Further, the height h1 of the sharp portion in the projection structure of the present invention means the length in the plate perpendicular direction from the lowest portion to the apex of the sharp portion.

  The width a2 of the prism portion in the protrusion structure of the present invention refers to the width of the portion in contact with the plate surface in the protrusion cross section. In addition, the height h2 of the prism portion in the projection structure of the present invention refers to the length in the plate normal direction from the uppermost portion of the prism portion (that is, the lowermost portion of the sharp portion) to the plate surface.

  The bottom shape of the prismatic part in the protruding structure of the present invention refers to the shape of the prismatic part on the plate surface. In the present invention, the relationship between the pitch of the protrusions and the width of the sharp portion formed of a pyramid shape is preferably P / a1 ≦ 2.5. That is, the relationship between the pitch of the protrusions and the width of the sharp portion formed of a pyramidal shape is P / a1 ≦ 2.5 means that the protrusions are densely arranged on the plate surface. Here, when P / a1 ≦ 2.5, the outer shape of the microneedle can be reduced, and the medicine can be efficiently administered to the human body. Further, the presence of the sharp portion can improve the puncture property. In the separation filter, the through holes can be arranged densely, and the object can be separated efficiently.

  In the present invention, it is preferable that (h1 + h2) / a2 ≧ 2. That is, (h1 + h2) / a2 ≧ 2 means that the amount of chemicals retained in the microneedle is increased. An increase in the amount of drug held per microneedle enables efficient drug administration. In the separation filter, since the penetrable thickness is increased, a thick filter can be manufactured.

  In the present invention, the width of the prism portion is preferably 50 μm or less. That is, the projection in the present invention is fine. Since the protrusions are fine as described above, the puncture property of the microneedle is improved, the stimulation is reduced in puncturing the skin, and pain can be suppressed. In the separation filter, since the pore diameter is fine, it can be separated according to the size of the object such as various cells.

  In the projection of the present invention, the sharp portion and the prism portion can have a sectional shape of the projection as shown in FIGS. 3A to 3H in order to arrange them closely without impairing the puncture property. Combinations of prismatic sections (Figs. 3 (a) to 3 (c)) in which the angle formed between the outline in the cross section of the protrusion and the perpendicular to the plate surface is 0 degrees, the outline in the cross section of the protrusion and the perpendicular to the plate surface There are combinations (FIGS. 3D to 3F) including a prism portion having an angle greater than 0 degrees, or curved surfaces (FIGS. 3G to 3H).

  4A to 4H schematically illustrate the bottom surface of a prismatic part of a mold having a discrete protrusion structure according to the present invention. In the present invention, it is preferable that the bottom surface of the prismatic part is any one of three, four, six and octagons. Since the bottom surface of the prism portion is any one of the three, four, six, and octagonal shapes, the protrusions can be arranged closest to the plate surface.

  FIG. 5 schematically illustrates the sharp part of the mold having the discrete protrusion structure of the present invention. In the present invention, the apex of the sharp portion has R, and the range is preferably R ≦ a1 / 4. A preferable range of R is 0.01 μm to 1 μm. Since the apex has R, the risk of breakage at the time of piercing can be reduced when the through hole is formed.

  Next, an example of a method for producing a mold protrusion having a discrete protrusion structure according to the present invention will be described with reference to FIG. The surface of the plate 23 (FIG. 6A) is cut from one direction with a tool to form a groove (FIG. 6B). Thereafter, the tool is rotated 90 degrees, and the surface of the plate 23 is cut again from the second direction (FIG. 6C). Thereafter, cutting can be performed stepwise in the depth direction (FIG. 6D), and the projections 20 can be formed on the plate 23 (FIG. 6E). By using a diamond tool, a narrow groove can be formed, and a high aspect shape can be arranged on the surface of the plate 23 more densely than that produced by a rotating tool.

  The material which comprises the metal mold | die which has the discrete protrusion structure of this invention is not restrict | limited in particular. In manufacturing the mold, it is preferable to form the protrusion on the plating layer. Therefore, it is preferable to perform plating such as electroless Ni—P plating on the surface or region of the mold to be cut. This is because the corrosion resistance and wear resistance of the mold are greatly improved by performing plating, and high-precision processing is possible in subsequent cutting. The plating film thickness in the plating process can be appropriately set according to the depth of the groove to be formed and the purpose of use. In addition, various materials such as copper and aluminum alloys, glass, silicon, and stainless steel can be used as mold materials. In the method of manufacturing by cutting, a tool is scanned on the plating to form a protrusion on the mold surface. The tool trajectory is preferably scanned from two or more directions so that projections are formed during cutting. The tool trajectory may be set as appropriate in accordance with the shape of the protrusion to be formed.

According to said cutting, a metal mold | die can be cut into various shapes, Thereby, the molded article using this metal mold | die can also be formed in various shapes. For example, the convex shape or the concave shape formed in the molded part can form a polygonal pyramid such as a triangular pyramid, a quadrangular pyramid, a hexagonal pyramid, or an octagonal pyramid.
The mold manufacturing method includes direct cutting, laser processing, and electron beam processing on the metal surface, direct cutting, laser processing, and electron beam processing on the plating layer formed on the metal surface. The method of casting is mentioned. Moreover, after apply | coating a resist on a board | substrate, after forming a resist by predetermined patterning with a photolithographic technique, the board | substrate is etched, The method of obtaining the inversion pattern by electroforming after resist removal etc. is mentioned. A concave pattern can be obtained by applying anisotropic etching. As the substrate, a silicon substrate or the like can be applied in addition to the metal plate.

  A machine tool that can be used for machining into a mold is preferably one that can be precisely cut. The tool cutting edge material used can be any material such as high-speed steel, cemented carbide, cermet, ceramics, etc., but if you consider precise and ultra-fine cutting, use a diamond tool. desirable.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

Example 1
As a plate, the surface of a stainless steel plate was coated with a material mainly composed of Ni having free machinability to a thickness of about 100 μm. Thereafter, the Ni portion was cut from three directions with a diamond tool to form a sharp portion on the plate surface. Thereafter, cutting was performed stepwise in the depth direction to form a prismatic portion, and the following shape was obtained.
Shape of sharp part: height of hexagonal pyramid sharp part h1: 4 μm
Sharp part width a1: 8.3 μm
Bottom shape of prismatic part: height h2 of hexagonal prismatic part: 24 μm
Square column width a2: 9.4 μm
Projection height: 28 μm
Protrusion pitch: 17 μm
Size: 25 mm × 25 mm (pattern area).

  The obtained metal mold | die was observed using the Keyence Corporation laser microscope (VK-8510), and the obtained cross-sectional profile is shown in FIG. As shown in FIG. 7, the obtained mold had a sharp portion, and high aspect protrusions were densely arranged. ((P / a1 = 2.05), (h1 + h2) /a2=2.86).

  Since the mold having the discrete protrusion structure of the present invention has a high aspect and the protrusion structure is densely arranged, the molded product obtained by the mold of the present invention can be used for cell separation, filtration membrane, gas permeation, etc. It can be used for filters having the above functions, super water-repellent films, antifouling films, microneedles and the like.

10: Mold 20 having a discrete projection structure 20: Protrusion 21: Sharp portion 22: Square column portion 23: Plate a1: Sharp portion width a2: Square column portion width h1: Sharp portion height h2: Square column portion height P : Projection pitch

Claims (4)

A mold having protrusions regularly arranged on the surface of the plate, the protrusions including a sharpened portion having a pyramid shape and a prism portion serving as a base of the sharpened portion,
When the width of the sharp part is a1, the height of the sharp part is h1, the pitch of the protrusion is P, the width of the prism is a2, and the height of the prism is h2, the following formulas (i) to ( A mold having a discrete protrusion structure that satisfies iii).
P / a1 ≦ 2.5 (i)
(H1 + h2) / a2 ≧ 2 (ii)
h1 <h2 (iii) The metal mold | die which has the discrete protrusion structure of Claim 1 whose width | variety a2 of the said prismatic part satisfy | fills the following formula | equation.
a2 ≦ 50μm   The metal mold | die which has a discrete protrusion structure of Claim 1 or 2 whose bottom face shape of the said prismatic part is a shape in any one of a three, four, six, and octagon. The metal mold | die which has the discrete protrusion structure in any one of Claims 1-3 in which the vertex of the said sharp part has R, and this R satisfies the following formula | equation.
R ≦ a1 / 4

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