JP2012066417A - Mold, method for manufacturing the same, method for manufacturing resin molding using the mold, and resin molding manufactured by the method for manufacturing the resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold which gives water repellency to a plastic molding.SOLUTION: The mold 10 which forms a water-repellent area on a surface of a resin molding includes a mold body part 11 and a plating part 12 formed on at least a part of an inner peripheral surface of the mold body part 11. The plating part 12 has a minute periodic structure 20 on a contact surface side which resin material contacts. The minute periodic structure 20 is formed by having its cross section of a sawteeth-shape where V-shaped concave parts are closely arranged. The concave part expands toward the inside of a mold storing the resin material. A dimension between both shoulders of the concave part is equal to or larger than 1.0 μm and smaller than 100 μm.

Description

  The present invention relates to a mold for molding a resin molded body such as a plastic molded body, and in particular, a mold capable of imparting water repellency to a desired portion of the surface of the resin molded body, a method for manufacturing the mold, and the use of this mold. The present invention relates to a method for producing a molded resin product and a resin molded product produced by the production method.

  In the medical field, there is a high demand for using disposable plastic medical tools from the viewpoint of prevention of infections to medical staff and convenience in the diagnosis field. For example, reagents called kit products are integrated. In addition, products made up of multiple plastic parts are increasing year by year.

  In blood tests, plastic test chips equipped with micro-channels are frequently used, and in order to reduce the burden on patients and physical pain, the amount of blood collected is reduced to 1 μL or less. In order to improve the analysis technology, a transport technology that sends a very small amount of collected sample to the analysis unit without waste is essential. For this reason, it is important to prevent adhesion and retention or diffusion of blood and proteins contained in it to plastic tools such as microchannels, and this requires extremely controlled hydrophilicity and water repellency in the microchannels. It is effective. For example, if water repellency can be intentionally imparted to a desired portion of the microchannel, the sample can be sent reliably.

The water repellency is one form of the property of “the shape can be easily changed”, which the liquid has, and indicates the ease with which the liquid adheres to the solid surface, which is called “wetting”. In order to express water repellency objectively and quantitatively, a contact angle is often used, which indicates static water repellency.
The contact angle is an angle θ on the side containing the liquid among the angles formed by the tangent to the liquid surface and the solid surface at the point where the solid is in contact with the liquid surface, as shown in FIG.
Hydrophilicity: θ <90 °
Water repellency: 90 ° <θ <150 °
Super water repellency: 150 ≦ θ ≦ 180 °

  Until now, water repellency has been "chemically" applied to the product surface by applying a water-repellent polymer such as a fluororesin, but it is difficult to apply to medical devices due to problems such as peeling of the coating layer.

The cleaning effect due to water repellency resulting from the fine structure of the surface is conventionally known as the Lotus effect.
Non-Patent Document 1 experimentally reports that it is necessary to satisfy the following physical conditions (1) to (3) at the same time in order to develop the Lotus effect.
(1) It has a periodic uneven structure.
(2) The uneven pitch is about 5 to 20 μm.
(3) As shown in FIG. 13, the aspect ratio (a / b) of the groove width (a) and the protrusion width (b) is 2 or less.

Reiner Furstner and Wilhelm Barthlott, "Wetting and Self-Cleaning Properties of Artificial Superhydrophobic Surfaces", Langmuir 2005, 21, 956-961, Furstner & Barthlott, Langmuir, 21, 2005 Solga A, Cerman Z, Striffler BF, Spaeth M, Barthlott W: The dream of staying clean: Lotus and biomimetic surfaces, Bioinspir Biomim, 2 (4), S126-S134, 2007 Tomohiko Kawai, Kenzo Sugawara, Akira Yamamoto, Takayuki Oda, Yasuhiro Saida, Hiroshi Minami, Takeshi Ohki, Fuminobu Nakamura, Kazuyoshi Yaha: Development of Ultra-precision Machining Machine, Proc. C (2004) 2723 -2729

Although the industrial application of the Lotus effect has already begun, a method of applying micron-sized fine particles to the surface of an object is the mainstream.
In addition, as a processing method of an object for forming a fine structure, blasting in which abrasive particles are sprayed on the surface with compressed air is known, but forming a regular periodic structure on the surface of the object Impossible. Surface processing with a femtosecond laser with a wavelength of 800-1200 nm is not suitable for a relatively rough treatment of 5-20 μm because the period of irregularities is limited by the wavelength of the laser.

  Non-Patent Document 1 discloses conditions (1) to (3) for expressing water repellency. However, water repellency is imparted to plastic molded articles such as plastic medical devices, which have been used in recent years. Non-patent document 1 does not disclose any technique to be applied. That is, for a molded body produced by pouring resin into a mold such as a plastic molded body, it is necessary to devise the mold so that the molded body transferred from the mold has water repellency.

  The present invention was created in view of the above points, and was manufactured by a mold for imparting water repellency to a plastic molded body, a manufacturing method thereof, a manufacturing method of a resin molded body using the mold, and a manufacturing method thereof. It aims at providing the resin molding.

  In order to achieve the above object, a first configuration of the present invention is a mold for forming a water-repellent region on the surface of a resin molded body, and includes a mold body portion and an inner peripheral surface of the mold body portion. A plated portion formed at least in part, and the plated portion has a fine periodic structure on the side of the contact surface with which the resin material abuts, and the fine periodic structure has a sawtooth shape in which V-shaped concave portions are connected without gaps. It is formed in the cross section, the recess is expanded toward the inside of the mold in which the resin material is accommodated, and the dimension between the shoulders of the recess is 1.0 μm or more and less than 100 μm. It is a feature.

  In the mold of the present invention, the fine periodic structure is composed of a plurality of pyramids. As the pyramid, for example, a quadrangular pyramid, a triangular pyramid, a hexagonal pyramid, or the like can be used.

In the mold of the present invention, the fine periodic structure is composed of a plurality of grooves formed in the plated portion, and the grooves are formed in a V-shaped cross section, and at least the following (A1) to (A2) Have either.
(A1) A straight line portion extending in one direction.
(A2) A curved portion extending so that the extending direction gradually bends.

  In order to achieve the above object, a second configuration of the present invention is a mold for forming a water-repellent region on the surface of a resin molded body, and includes at least a mold main body and an inner peripheral surface of the mold main body. A plating part formed in part, and the plating part has a fine periodic structure on the side of the contact surface with which the resin material abuts, and the fine periodic structure has a plurality of square pyramids of the same shape on the mold surface. And the first axis direction along the first axis direction and the second axis direction along the surface intersecting the first axis direction, and the spacing between the apexes of adjacent quadrangular pyramids is 1.0 μm or more It is characterized by being less than 100 μm.

In the mold of the present invention, a first pitch that is an interval between the vertices of the quadrangular pyramids along the first axial direction and a second pitch that is an interval between the vertices of the quadrangular pyramids along the second axial direction are The angle α formed by the first axial direction and the second axial direction is selected as one of the following (C1) to (C2). Yes.
(B1) 1st pitch = 2nd pitch (B2) 1st pitch> 2nd pitch (B3) 1st pitch <2nd pitch (C1) α = 90 °
(C2) α ≠ 90 °

In order to achieve the above object, a third configuration of the present invention is a method for manufacturing a mold, in which a first step of forming a plated portion on a workpiece surface of a workpiece and a flat upper surface of the plating portion And a third step of forming a fine periodic structure by cutting the surface flattened in the second step.
This method for manufacturing a mold preferably further includes a fourth step of heat-treating the plated portion.

The 4th structure of this invention for achieving the said objective is the manufacturing method of the molded object which manufactures a resin molded object using the said metal mold | die.
A fifth configuration of the present invention for achieving the above object is a resin molded body manufactured by the manufacturing method.

  According to the present invention, a plastic molded body can be manufactured by injection molding. For example, a material made of a thermoplastic resin is heated and softened, pressed into a mold, and cooled to be solidified. Thereby, a water-repellent region can be formed on the surface of the plastic molded body.

It is a top view which shows the one part surface of the metal mold | die which concerns on 1st Embodiment of this invention. It is sectional drawing of the metal mold | die along the AA line of FIG. It is a flowchart which shows the manufacturing method of the metal mold | die which concerns on 1st Embodiment of this invention. It is a schematic plan view of the surface of the metal mold | die which concerns on 2nd Embodiment of this invention. It is a schematic plan view of the surface of the metal mold | die which concerns on the modification of 2nd Embodiment of this invention. It is a top view which shows the one part surface of the metal mold | die which concerns on 3rd Embodiment of this invention. It is a perspective view which shows the one part surface of the metal mold | die which concerns on 4th Embodiment of this invention. It is a plane photographic image of the surface of the sample concerning an embodiment of the present invention. It is a figure which shows the measurement result of the surface roughness of each sample. It is a figure which shows the contact angle of each sample and a resin molded product. (A) And (B) is a figure which shows the immunosensor which concerns on the Example of this invention. It is a figure for demonstrating water repellency. It is a schematic sectional drawing which shows the uneven structure for expressing a lotus effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings where necessary.

[First Embodiment]
FIG. 1 is a plan view showing a partial surface of a mold 10 according to the first embodiment of the present invention. The mold 10 is a mold for forming a water-repellent region on at least a part of the surface of a plastic molded body. In order to form the water-repellent region in the plastic molded body, the mold 10 is provided with a fine periodic structure 20 on at least a part of the inner surface 10A of the mold as shown in FIG. FIG. 2 is a cross-sectional view of the mold 10 taken along line AA of FIG.

As shown in FIG. 2, the mold 10 includes a mold main body 11 and a plating part 12 provided on the inner surface of the mold main body 11.
The fine periodic structure 20 is formed by processing the plated portion 12, and has a pyramid that is a plurality of fine structures. Each pyramid is formed in the same shape, and in this embodiment, the pyramid is formed in a quadrangular pyramid 21 in which one side is selected to have a size of the order of several tens of μm.

Each square pyramid 21 is aligned and formed on the mold surface. Specifically, adjacent quadrangular pyramids 21 are formed with a common side (hereinafter sometimes referred to as a base) forming the bottom thereof, and the bases between adjacent quadrangular pyramids 21 are linear. The quadrangular pyramids 21 are aligned so that they are arranged in a straight line, for example, along the X direction (see FIG. 1) which is the first axial direction and the Y direction (see FIG. 1) which is the second axial direction. Is formed. The angle α formed by the X direction and the Y direction is selected as 90 ° in this embodiment. The quadrangular pyramid 21 in the illustrated example is formed as a regular quadrangular pyramid. In the present embodiment, as shown in FIG. 2, the fine periodic structure 20 is formed in a sawtooth cross section in which V-shaped concave portions 22 are connected without gaps. A plurality of sawtooth cross sections are formed in the X and Y directions, specifically, at intervals of pitches P _X and P _Y described later. As shown in FIG. 2, the recess 22 is formed in a V shape by surfaces passing through the bottom 21 </ b> B and a pair of tops 21 </ b> A as shoulders on both sides and on the upper side.
In FIG. 1, a solid line represents a ridge line extending from the bottom 21B to the top 21A, a broken line represents a line of the bottom 21B, and a one-dot chain line represents a shoulder line.

In the present embodiment, the pitch L (FIG. 2) that is the interval between the apexes 21A of the adjacent quadrangular pyramids 21 is set to 1.0 μm ≦ L <100 μm. If the pitch L is too small, the plastic molded body using the mold cannot lower the contact angle and exhibit water repellency. This is considered to be because when the pitch L is smaller than 0.8 μm, the shape formed by the fine structure formed on the inner surface of the mold is not sufficiently transferred to the plastic molding. On the other hand, when the pitch L was 1.0 μm, the fine periodic structure 20 could be transferred to the plastic molded body. On the other hand, when the pitch L is larger than 100 μm, the contact angle is in the range of 0 ° to 90 ° and exhibits hydrophilicity. In addition, it has been conventionally known that when the pitch is larger than 100 μm, hydrophilicity is exhibited (Non-Patent Documents 1 and 2). In FIG. 1, the pitch in the X direction is represented as P _X, and the pitch in the Y direction is represented as P _{Y. In} this embodiment, P _X and P _Y are set to the same dimension.
Further, d is the height of each square pyramid 21 and the depth of the recess 22 is d, and this d is selected on the order of several tens of micrometers as with the pitch L.
As the plating part 12 on which such a fine periodic structure 20 is formed, a nickel film or a copper film can be used (Non-Patent Document 3). In this embodiment, the plating part 12 can be formed by electroless plating, for example. Further, the crystal of the plated portion 12 is amorphous.

  The material for forming the mold main body 11 is not particularly limited as long as it is normally used, and die steel, powdered high-speed steel, cemented carbide or the like can be used.

The manufacturing method of the metal mold | die 10 of this embodiment is demonstrated using the flowchart of FIG.
For example, when it is desired to impart water repellency to a part of the surface of a plastic molded body, a mold used for injection molding the plastic molded body is referred to as a mold body 11 (hereinafter referred to as a workpiece). ) Is prepared (step S1).
Corresponding to the surface portion of the plastic molded body to which water repellency is to be imparted, the plated portion 12 is formed on a part of the processed surface of the workpiece, specifically, on a part of the inner peripheral surface of the mold. (Step S2). For example, a nickel film having a thickness of about 100 μm is deposited on the work surface of the work piece by electroless (Ni—P) plating. The thickness of the film may be, for example, several tens of μm to several hundreds of μm.
Next, the upper surface of the plating part is flattened using a flat plate groove processing machine (step S3). For example, the nickel film is cut and flattened to a flatness of the order of 10 nm.
The flat plate grooving machine is a kind of cutting machine, and the tool is a device used to perform grooving on a two-dimensional plane using a single crystal diamond with sharp edges and few irregularities. The processing method is mainly milling using a rotary tool. Even with a microstructure of the order of 10 μm, the cutting reaction force is very small, so that it can be processed by manufacturing a minute tool.
Further, the workpiece is cut by exchanging the cutting tool of the flat plate grooving machine while the workpiece is fixed, and the fine periodic structure 20 shown in FIG. 1 is formed (step S4). In this case, the workpiece is processed with a diamond tool.
For example, as shown in FIG. 1, a plurality of V-shaped grooves extending in the X direction are formed side by side on the surface of the flattened plating portion 12, and the cross-section V-shaped extending in a direction that forms an angle α with the X direction. A plurality of rectangular groove portions are formed side by side, and a plurality of quadrangular pyramids 21 are formed at each pitch L by intersecting the groove portions. Thus, the X direction and the Y direction are collectively referred to as a biaxial direction, and cutting that forms a groove in the biaxial direction is referred to as “biaxial cutting”. The “biaxial laser processing” to be described later is a method of forming a groove portion extending in the biaxial direction by laser processing here.

  The fine periodic structure 20 of the mold 10 is transferred to the plastic molded body molded using the mold 10 formed in this manner, and a water-repellent region is formed. In this case, water repellency with a contact angle θ of 90 ° or more could be expressed on the surface of the plastic molded body.

  Thus, a plastic molded body can be manufactured by injection molding using the mold 10 of the present embodiment. For example, a material made of a thermoplastic resin is heated and softened, pushed into a mold, and further cooled and solidified. Thereby, the area | region which has water repellency can be formed in the surface of a plastic molding.

According to Non-Patent Document 1, a rectangular cross-section concave portion 210 and a rectangular cross-section convex portion shown in FIG. 13 are provided on a metal processing surface at a pitch of 5 to 20 μm to impart water repellency to the metal processing surface. 220 is regularly formed, but in order to actually perform processing on the order of several μm, the processing surface of the metal is processed to have a flatness and surface roughness of the order of 10 nm, which is two orders of magnitude lower than that. It is necessary to pre-process the surface. However, if the chamfering and the processing of the fine periodic structure are performed with different processing machines, it is impossible to achieve a flatness of the order of 10 nm.
On the other hand, according to the method for manufacturing the mold 10 of the present embodiment, a workpiece made of a mold forming material is prepared, a nickel film is formed on the workpiece surface of the workpiece, and the nickel film is formed. In order to process, it is possible to form a fine structure by cutting after flattening. This is based on the fact that, since the particles of the plating part 12 are finer than the mold body part 11, the processing on the nano-micron order is easy and the hardness is hard.

  Furthermore, after the plated portion 12 is processed to form the fine periodic structure 20, the nickel film is crystallized by heat-treating the amorphous structure of the nickel film, thereby improving the wear resistance. Further, even if electroless plating is used as the plating portion 12, only the electroless plating treatment is performed on a part of the mold surface so as to impart a water repellent effect to a part of the surface of the plastic molded body. The load can be minimized.

[Second Embodiment]
FIG. 4 is a schematic plan view of the surface of the mold 30 according to the second embodiment of the present invention, particularly the fine periodic structure 20.
As shown in this figure, in the mold 30 according to the second embodiment, each quadrangular pyramid 21 constituting the fine periodic structure 20 is formed in a rectangular pyramid having a rectangular bottom surface. Specifically, in the illustrated example, the pitch P _{X in the} X direction is set larger than the pitch P _{Y in the} Y direction. In the present embodiment, as in the first embodiment, the angle α formed by the X direction and the Y direction is selected to be 90 ° in the present embodiment.
In the plastic molded body molded by such a mold 30, in the water-repellent region formed by transferring the fine periodic structure 20 of the mold 30, the long side of the bottom surface of the rectangular cone extends, that is, X in the illustrated example. Water drops easily flow to the direction side.

[Modification of Second Embodiment]
FIG. 5 is a schematic plan view of the surface of the mold 40 according to a modification of the second embodiment of the present invention, particularly the fine periodic structure 20.
As shown in this figure, in the mold 40 according to the present embodiment, the bottom surface of each square pyramid 21 constituting the fine periodic structure 20 is formed in a rhombus. Specifically, in the illustrated example, the pitch P _Y pitch P _X and Y direction of the X direction is selected to be the same size, in the present embodiment, unlike the embodiment described above, X and Y directions Is selected to be greater than 90 °.
In the plastic molded body molded by such a mold 40, in the water-repellent region formed by transferring the fine periodic structure 20 of the mold 40, water droplets extend in the direction in which the long diagonal line (dashed line 41 in the figure) extends. It becomes easy to flow.
As another application example, the bottom surface of each quadrangular pyramid 21 may be formed into a parallelogram with P _X ≠ P _Y and an angle α ≠ 90 ° (where α ≠ 0, 180) instead of a rhombus.
In this way, the pitch P _{X in the} X direction and the Y direction defining the first side forming the bottom surface of the quadrangular pyramid and the second side connected to the first side and forming the angle α with the first side. By changing the pitch P _Y and the angle α, it is possible to control the direction in which water drops on the surface of the plastic molded body flow.

[Third Embodiment]
FIG. 6 is a plan view showing a part of the surface of the mold 50 according to the third embodiment of the present invention. Similar to the mold 10 according to the first embodiment, the mold 50 includes a mold body 11 and a plating part 12, and a fine periodic structure 20 is formed by processing the plating part 12. Yes. In the fine periodic structure 20 of the present embodiment, a pyramid that is a plurality of fine structures is formed in the triangular pyramid 25. Each triangular pyramid 25 is formed in the same shape, and in this embodiment, one side is selected to have a dimension size on the order of several tens of μm.

The triangular pyramids 25 are aligned and formed on the mold surface. Specifically, the adjacent triangular pyramids 25 are formed with a common base that forms the bottom thereof, and each triangular pyramid 25 has, for example, a first axis so that the bases of the adjacent triangular pyramids 25 are connected in a straight line. The X direction (see FIG. 6) as the direction, the Y direction (see FIG. 6) as the second axial direction, and the Z direction (see FIG. 6) as the third axial direction are arranged in a straight line. It is formed with the same position. In this embodiment, the angles α1 and α2 formed by the respective directions are selected to be 60 °. The triangular pyramid 25 in the illustrated example is formed in a regular triangular pyramid. Similar to the first embodiment, the fine periodic structure 20 of the present embodiment is formed in a sawtooth-shaped cross section in which V-shaped concave portions 22 are connected without gaps (the shape is different from that of the first embodiment). A plurality of sawtooth cross sections are formed in the X direction, the Y direction, and the Z direction, specifically, at a predetermined pitch interval. In FIG. 6, the solid line represents the ridge line extending from the bottom 21 </ b> B of the recess 22 to the top 21 </ b> A, and the broken line represents the line of the bottom 21 </ b> B.
Also in this embodiment, the pitch L is set to 1.0 μm ≦ L <100 μm, where the interval between the apexes 21A of the adjacent triangular pyramids 25 is the pitch L.

  The fine periodic structure 20 of the mold 50 is transferred to the plastic molded body molded using the mold 50 formed in this manner, and a water-repellent region is formed.

[Fourth Embodiment]
FIG. 7 is a perspective view showing a part of the surface of a mold 60 according to the fourth embodiment of the present invention. Similar to the mold 10 according to the first embodiment, the mold 60 includes a mold body portion 11 and a plating portion 12. The fine periodic structure 20 of the present embodiment includes a plurality of groove portions 27 formed in the plated portion 12. Each groove portion 27 is formed in a V-shaped cross section. The groove part 27 is expanded toward the inside of the mold in which the resin material is accommodated, and the dimension between both shoulders of the groove is set to 1.0 μm or more and less than 100 μm. These groove portions 27 are adjacent to each other and share a V-shaped groove shoulder 27A.
As described above, the fine periodic structure 20 of the present embodiment is also formed in a sawtooth cross section in which the V-shaped concave portions 22 are connected without gaps, as in the above-described embodiment.
The groove portion 27 in the illustrated example is formed as a straight portion extending in one direction (D1 direction in FIG. 7) over its entire length.

  The fine periodic structure 20 of the mold 60 is transferred to the plastic molded body molded using the mold 60 formed in this manner, and a water-repellent region is formed.

Next, experimental examples will be described.
Experimental purpose: Evaluation of water repellency of plastic moldings transferred from molds Experimental conditions:
Die: Die steel (SKD11) was prepared as a steel material used for the mold. The following four samples were prepared using the metal mold to be evaluated.
Sample 1: Mold itself (so-called SKD11 equivalent as a base material)
Sample 2: Mold having a non-periodic structure by blasting the surface Sample 3: Mold having a fine periodic structure by biaxial laser processing on the surface Sample 4: Having a fine periodic structure by biaxial cutting on the surface Mold Here, the sample 4 corresponds to the mold of the embodiment of the present invention, and an electroless plating process is performed on the die steel (SKD11) to form a plated portion, and an upper surface of the plated portion is formed. The fine periodic structure 20 was formed by performing a flattening process and further performing a V-shaped groove processing along the same direction on the flat surface 71 in the biaxial direction. FIG. 8 is a plan photographic image of the surface of the sample 4. The fine periodic structure 20, that is, a plurality of quadrangular pyramids 72 were formed adjacent to the surface 71 by this biaxial cutting.
Resin material: 100% polyacid (manufactured by Unitika Ltd., “Teramac”, TE-2000)
Molding machine: A 40 ton molding machine was used with a speed of 33% and a pressure of 30%.
Molding temperature condition: The material manufacturer recommends a mold temperature of 10-30 ° C and a cylinder temperature of 180-210 ° C. As a result of implementation and error, the mold temperature is 30 ° C, the nozzle temperature is 230 ° C, and the front temperature. 235 ° C., central temperature 230 ° C., rear temperature 225 ° C.
Evaluation method of water repellency: Static water repellency was determined by contact angle.
Measurement of contact angle: A microscope (VH-E500, Keyence, × 50) and image analysis software (Image J, open source free software) were used.
Other: To remove the influence of the surface roughness of the base material surface on the contact angle, the surface of the base material before processing the fine structure is polished to a center line average roughness Ra = 0.05 μm. It was. For the measurement of the surface roughness, a three-dimensional surface roughness meter (sv-3000m4, Mitutoyo Corporation) was used.

FIG. 9 shows the measurement results of the surface roughness of each sample, and FIG. 10 shows the contact angle between the mold and the resin molded product of each sample 1-4, that is, static water repellency.
The initial value of the contact angle θ was 78.1 ° for the mold steel (equivalent to SKD11) as the sample 1 and 52.0 ° for the surface of the sample 1 subjected to Ni—P plating. The difference between the two is considered to be the effect of the surface free energy of the material. In the non-periodic structure obtained by blast processing of Sample 2, it was difficult to perform processing rougher than Ra = 0.21 μm, but the contact angle θ was improved by 17.9 °. Sample 3 having a periodic structure with a pitch L = 0.4 to 0.8 μm by biaxial laser processing has a periodic structure with a contact angle θ of +57.4 degrees from the initial value and a pitch L = 10 μm by biaxial cutting. In Sample 4, the contact angle θ was greatly improved to + 43.7 ° from the initial value.
Furthermore, the water repellency of the plastic molded body to which the mold having the fine periodic structure of Sample 3 and Sample 4 is transferred will be described.
First, as shown in FIG. 10, in the plastic molded body using the mold of Sample 3, the contact angle θ is 44.6 ° lower than the contact angle θ (= 135.5 °) of the mold itself, and 90 It was 9 °. This was thought to be because the fine periodic structure was not fully transferred due to the low-fluidity biomass plastic. From this, it can be understood that the pitch L of the fine periodic structure 20 is desirably larger than 0.8 μm.
On the other hand, as shown in FIG. 10, in the sample 4, that is, the plastic molded body using the mold according to the embodiment of the present invention, the contact angle θ is 14 from the contact angle θ (= 95.7 °) of the mold itself. Increased by 4 ° to 110.1 °. In this embodiment, it was improved 58.1 ° compared to before processing.

  As can be seen from the experimental results, it was confirmed that a plastic molded body having water repellency could be produced using the mold of the present embodiment.

Next, an example of a plastic product using the mold of the present invention will be illustrated.
[Immunosensor]
When a 1 μL blood sample is dropped into the microchannel, the immunosensor separates the blood cells, supplements the substance to be measured with the antibody immobilized on the electrode, and quantitatively analyzes the blood sample by an electrochemical reaction. As shown in FIG. 11A, the immunosensor 100 accommodates, for example, a microchannel 101, a blood cell separation membrane 102, a holder 103 that supports the blood cell separation membrane 102, an electrode portion 104, and an electrode portion 104. And a housing 105.
In this immunosensor 100, it is necessary to prevent blood from adhering to and staying on the microchannel 101, the holder 103, the plastic portion of the electrode portion 104, and the inner peripheral surface of the partition wall of the housing 105. In this case, water repellent properties can be imparted to these members by additionally processing the fine periodic structure 20 of the present invention only on a desired portion of a mold that has already been prototyped. For example, an insertion piece corresponding to a portion requiring water repellency is incorporated into a mold and built-in injection molding is performed. A hatched portion in FIG. 11A is a portion to which the fine periodic structure 20 is applied, and Δ in FIG. 11B schematically represents a quadrangular pyramid 21 forming the fine periodic structure 20.
Thus, by applying the fine periodic structure 20 to each component of the immunosensor 100 to impart water repellency, the sensor sensitivity can be improved.

[Other use examples of the present invention]
New biosensors and chemical analysis methods have been proposed in the past, but even if they are excellent in principle, they are often not used in practice because they do not match the cost.
According to the present invention, super-water repellency can be imparted only to a desired portion of the inspection chip with the fine periodic structure 20 on the mold surface. Therefore, the present invention greatly contributes to the improvement of the accuracy of the medical test chip, and it is also possible to realize an analyzer technique that has not been used so far. For example, if high-precision analysis technology of the order of 10 pg / mL, which is an order of magnitude more sensitive than the current (0.1 ng / mL), is realized, early diagnosis and accuracy of cancer, hepatitis, infectious diseases, etc. will be improved. It can be expected that various diagnostic technologies will be put into practical use at once.
Further, the present invention can be applied not only to medical test chips but also to other medical products and industrial products.

Although detailed above, the present invention can be implemented in various forms without departing from the spirit of the invention.
Of course, the application of the present invention is not limited to medical devices, and may be used for other industrial purposes.
The fine structure constituting the fine periodic structure of the present invention is not limited to the quadrangular pyramid 21, the triangular pyramid 25, and the groove 27, but may be a pyramid such as another hexagonal pyramid. The groove part 27 is configured such that a part of the entire length is formed as a straight part, or a curved part (D2 direction indicated by a two-dot chain line in FIG. 7) is formed in which the extending direction of a part of the entire length is gradually curved. Of course, it may be.

10, 30, 40, 50, 60 Mold 10A Mold inner surface 11 Mold body 12 Plated portion 20 Fine periodic structure 21 Square pyramid 21B Groove bottom 25 Triangular pyramid 27 Groove

Claims (9)

A mold for forming a water-repellent region on the surface of a resin molded body,
A mold body, and a plating part formed on at least a part of the inner peripheral surface of the mold body,
The plated portion has a fine periodic structure on the contact surface side with which the resin material abuts,
The fine periodic structure is formed in a sawtooth cross section in which V-shaped concave portions are continuous without gaps,
The concave portion is expanded toward the inside of the mold in which the resin material is accommodated,
The metal mold | die characterized by the dimension between the both shoulders of the said recessed part being 1.0 micrometer or more and less than 100 micrometers.   The mold according to claim 1, wherein the fine periodic structure includes a plurality of pyramids. The fine periodic structure is composed of a plurality of grooves formed in the plated portion,
2. The mold according to claim 1, wherein the groove is formed in a V-shaped cross section and has at least one of the following (A1) to (A2).
(A1) A straight line portion extending in one direction.
(A2) A curved portion extending so that the extending direction gradually bends. A mold for forming a water-repellent region on the surface of a resin molded body,
A mold body, and a plating part formed on at least a part of the inner peripheral surface of the mold body,
The plated portion has a fine periodic structure on the contact surface side with which the resin material abuts,
The fine periodic structure is formed by arranging a plurality of quadrangular pyramids on the mold surface so as to intersect the first axial direction along the surface and the second axial direction along the surface intersecting the first axial direction. And
A mold characterized in that the interval between the apexes of adjacent quadrangular pyramids is 1.0 μm or more and less than 100 μm. The first pitch that is the interval between the apexes of the quadrangular pyramids along the first axial direction and the second pitch that is the interval between the apexes of the quadrangular pyramids along the second axial direction are the following (B1 ) To (B3), and the angle α formed by the first axial direction and the second axial direction is selected from any of the following (C1) to (C2) The mold according to claim 4, characterized in that:
(B1) 1st pitch = 2nd pitch (B2) 1st pitch> 2nd pitch (B3) 1st pitch <2nd pitch (C1) α = 90 °
(C2) α ≠ 90 ° A first step of forming a plated portion on the work surface of the work piece;
A second step of flattening the upper surface of the plated portion;
And a third step of forming a fine periodic structure by cutting the surface flattened in the second step.   Furthermore, the manufacturing method of the metal mold | die of Claim 6 including the 4th process of heat-processing the said plating part.   The molded object manufacturing method which manufactures a resin molded object using the metal mold | die of the said Claims 1-5.   A resin molded body manufactured by the method for manufacturing a molded body according to claim 8.