JP5630635B2 - MICROSTRUCTURE, ITS MANUFACTURING METHOD, AND AUTOMOBILE PARTS USING THE MICROSTRUCTURE - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a resin-made base having a plurality of fine protrusions and a durable fine structure including a functional layer coated with the fine protrusions, a method for manufacturing the same, and an automotive part using the fine structure. .

  By performing a treatment with a silane compound on an inorganic compound vapor-deposited film formed by sputtering or the like on the glass or resin surface, the substrate surface and the silane compound form a chemical bond, giving various performances semipermanently. It has been widely known that this is possible, and is widely used industrially.

  As an example of the treatment with a silane compound, a treatment for a front plate or a spectacle lens of a display screen used for an OA device or the like can be given. When a person uses the front plate or eyeglass lens of the display screen, dirt, fingerprints, sweat, cosmetics, and the like adhere to it. Therefore, by treating the surface with a certain kind of silane compound, it has been devised to make it difficult to adhere to such dirt or to easily wipe off the dirt.

For example, an article in which a stain-resistant film made of a fluoroalkylsilane compound layer is formed on the surface of a glass plate has been proposed (see Patent Documents 1 and 2).
An article in which a stain-resistant film made of a fluoroalkylsilane compound and a polysiloxane compound is formed on the surface of a glass plate has also been proposed (see, for example, Patent Document 3).

  Furthermore, since the window for construction has a problem that dirt due to rain, mud, exhaust gas or the like adheres and the transparency of the base material is lost, the anti-contamination treatment is desired. In order to impart stain resistance to the resin surface, there is generally a technique of coating the surface with a fluorine-based resin such as polytetrafluoroethylene or polyvinylidene fluoride.

JP-A-2-248480 JP-A-6-184527 JP-A-6-256756

However, in such a prior art, no matter how much these fluorine-based resins are coated on a flat surface, in principle, the static contact angle cannot exceed 120 °. For example, Japanese Patent Laid-Open No. 9-137117 As disclosed in the publication, its performance is limited.
Furthermore, the conventional silane compound coating can be formed only on the glass surface, and even if the coating is formed on a general resin surface, it does not have a bond with the base material, so it has a drawback that it is easily peeled off. there were.

Also, a method of forming a silane compound film on a resin substrate has been proposed, but even in that case, a vapor-deposited film made of an inorganic compound such as silicon dioxide must be formed on the resin surface. However, there is a problem that the cost is high.
On the other hand, in the method of coating the resin surface with the fluororesin, some chemical bonding is necessary because the fluororesin is poor in adhesiveness with the base resin. Although the silane compound has a functional group for forming a chemical bond with the substrate, the general resin surface often does not have a functional group for reacting with the silane compound.

  The present invention has been made in view of such problems of the prior art. The object of the present invention is to have a fine structure having a functional layer coated with a resin base and having excellent durability. It is an object of the present invention to provide a manufacturing method and an automobile part using the microstructure.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by applying a predetermined silicon compound to the fine protrusions disposed on the resin base. The present invention has been completed.

That is, the fine structure of the present invention is a fine structure having a resin base having a plurality of two-dimensionally continuous fine protrusions and a functional layer covering the fine protrusions, and the fine protrusions are Corona discharge treatment or plasma treatment has been performed, the wetting tension of the surface of the fine protrusion immediately after the treatment is 50 to 70 mN / m, and the fine protrusion comprises a cone-shaped convex portion. The top portion forms a circular or polygonal top surface, and the diameter Dt of the circle circumscribing the circular top surface or the polygonal top surface and the distance P between the tops of adjacent cone-shaped convex portions are Dt ≧ 0. 4P is satisfied, the distance P between the tops is 380 nm or less, the diameter Dt of the circumscribed circle is 30 nm or less, and the functional layer includes a compound containing silicon directly bonded to the surface of the fine protrusion. It is characterized by being formed.

  Moreover, the manufacturing method of the microstructure according to the present invention includes (A) a step of forming a resin base having the fine protrusions, and (B) the surface of the fine protrusions by subjecting the base to oxidation treatment or discharge treatment. And (C) covering the surface of the fine protrusion with a compound containing silicon to form a functional layer.

  Furthermore, the automobile part of the present invention is characterized by using the fine structure as described above.

  According to the present invention, since the predetermined silicon-based compound is applied to the fine protrusions disposed on the resin base, the fine structure having excellent durability, the manufacturing method thereof, and the fine structure are used. The auto parts that had been can be provided.

It is sectional drawing which shows the microstructure which concerns on 1st embodiment of this invention. It is a perspective view which shows the microstructure concerning 2nd embodiment of this invention. It is a perspective view which shows the microstructure which concerns on 3rd embodiment of this invention. It is a schematic explanatory drawing which shows the microstructure which concerns on 4th embodiment of this invention. It is a schematic explanatory drawing which shows the microstructure which concerns on 5th embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a fine structure according to the first embodiment of the present invention, FIG. 2 is a perspective view showing the fine structure according to the second embodiment of the present invention, and FIG. It is a perspective view which shows the microstructure which concerns on 3rd embodiment of this.
A fine structure according to the present invention includes a resin base having a plurality of two-dimensionally continuous fine protrusions and a functional layer covering the fine protrusions. The top-to-top distance P is 50 μm or less, and the functional layer is formed by chemically bonding a silicon-containing compound directly to the surface of the fine protrusion.
<Structure>
As shown in FIG. 1, the microstructure according to the first embodiment includes a resin-made base portion 10 having a flat plate shape, and cone-shaped projections 12 that are fine projections formed integrally with the base portion 10. The functional layer 20 covering the cone-shaped protrusion 12 is provided.
The cone-shaped protrusion 12 shown in the present embodiment is shown as a truncated cone shape as an example, but may be formed in a truncated pyramid shape.
Moreover, the cone-shaped protrusion 12 of the microstructure according to the second embodiment shown in FIG. 2 is formed in a conical shape, and the cone of the microstructure according to the third embodiment shown in FIG. The protrusion 12 is formed in a pyramid shape.
In addition, although the cone-shaped protrusion 12 shown in FIG. 3 has shown the thing of a quadrangular pyramid shape, it is not restricted to this, For example, it can form in a triangular pyramid shape, a pentagonal pyramid shape, etc.

Here, the “cone” basically means a pyramid having a planar side surface (a ridge line is a straight line) or a cone having a linear generatrix. However, the shape of the cone-shaped convex portion in the present invention is not limited to a cone or a pyramid in such an accurate sense, but as long as it has a tapered shape, the shape of a bell or vertebra that has a curved busbar or ridgeline shape. It may be a shape, a semi-spindle shape, or a pyramid having a two-dimensional curved surface or a three-dimensional curved surface.
In consideration of moldability and fracture resistance, the tip can be flattened or rounded. In the present invention, in addition to the original cone and pyramid, such shapes are included. It will be called “conical”.

  As shown in FIGS. 2 and 3, the plurality of cone-shaped projections 12 are two-dimensionally arranged, and the continuous directions x and y form about 90 °. The arrangement is not limited to the so-called orthogonal arrangement, and it is possible to adopt a so-called close-packed arrangement in which the continuous direction forms about 60 °.

1 to 3 have a circular or polygonal bottom surface. In FIG. 1, the diameter Db of the circle circumscribing the circular or polygonal bottom surface is 50 μm or less, and It is provided so that the distance P between the tops of the adjacent cone-shaped projections 12 is 50 μm or less.
Here, when the cone-shaped protrusion 12 is a truncated cone, the distance P between the peaks is a diameter of the top surface of the truncated cone having a circular shape or a polygonal shape or a distance between centers of circumscribed circles. In addition, when the cone-shaped protrusion 12 takes the above-mentioned close-packed arrangement, the larger distance (the longer pitch) is adopted as the inter-top distance P.
The top diameter Dt is the diameter of the top surface of the frustum that is circular or polygonal or the diameter of the circumscribed circle.

  It should be noted that the circumscribed circle diameter Db and the top portion distance P on the bottom surface do not necessarily have the same value. Both can be varied within the range of 50 μm or less, and can be varied between arbitrary cone-shaped convex portions and cone-shaped convex portions, but both are constant values within the range of 50 μm or smaller. It is preferable that both be taken, and it is more preferred that both take a constant value of 380 nm or less.

By controlling the circumscribed circle diameter Db on the bottom surface and the distance P between the tops to 50 μm or less, in particular, to a constant value within this range, the smoothness as a product can be maintained, and there is an advantage that there is no change in appearance. can get.
Note that if the distance P between the tops is controlled to 380 nm or less, preferably a constant value within this range, a fine structure having a protrusion pitch less than or equal to the visible light wavelength can be obtained, so that reflection of incident light can be prevented. The structure can be applied to a transparent member described later.

Further, the top diameter Dt is controlled to 30 nm or less, particularly to a constant value within this range . Thereby, the advantage that functions, such as antifouling property, super water repellency, and super hydrophilicity, can be provided, without impairing transparency as a product.

  Furthermore, in the microstructure of the present invention, the top diameter Dt and the distance P between the tops are controlled to a relationship of D ≧ 0.4P, preferably a constant value within this range, so that the surface of the microstructure and water It is possible to obtain a high static contact angle by reducing the contact area.

Furthermore, in the microstructure of the present invention, when the height of the cone-shaped protrusion 12 is H (see FIG. 1), the aspect ratio (H / Db) is preferably 0.2 to 10. .
By satisfying such an aspect ratio, it becomes easy to ensure the durability and productivity of the fine structure without impairing the function as a product.

In the microstructure of the present invention, the dynamic friction coefficient on the surface, specifically, the functional layer 20 is preferably 0.05 to 0.25, and more preferably 0.05 to 0.20. By having such a dynamic friction coefficient, excellent fracture resistance is expressed over a long period of time, and good durability can be realized.
When the dynamic friction coefficient exceeds 0.25, the slidability is deteriorated and the functional layer may be peeled off or broken, and it is difficult to develop various performances such as water repellency over a long period of time.

In the microstructure of the present invention, the wetting tension on the surface of the front of the cone-shaped projection 12 that covers the functional layer 20 shall be the 50~70mN / m.
When the wetting tension is less than 50 mN / m, the adhesion of the compound containing silicon element described later may not be exhibited. Further, when it exceeds 70 mN / m, the molecular weight of the resin constituting the cone-shaped protrusion 12 (the base 10 is the same in this embodiment), the destruction of the fine structure, and the durability of various performances due to embrittlement occur. Sometimes.
Such wetting tension can be typically realized by performing corona discharge treatment or plasma treatment on the cone-shaped convex portion, which will be described later.
Here, in the present embodiment, “immediately after processing” means a time zone before the functional layer 20 is coated as described above. Usually, there is a tendency for the wetting tension to increase as the elapsed time from the end of the corona discharge treatment or the plasma treatment is shorter, but it should be approximately within 3 hours from the end.

In the present invention, details of the mechanism that can realize the dynamic friction coefficient as described above are not clear at present, but it seems that the wet tension of the cone-shaped projections is a major factor in realizing the dynamic friction coefficient.
With regard to the expression of the wetting tension, it is presumed that a polar group is introduced by applying corona discharge treatment or the like to the cone-shaped convex portion, and is in accordance with the Wenzel equation.
Further, in the present invention, the details of the mechanism having durability against the mechanical addition as described above are not clear at present, but the mechanical characteristics of the resin constituting the cone-shaped convex portion may be a factor. Conceivable. That is, it is considered that structural destruction does not occur by converting the energy of the external force into heat energy in an elastic deformation region that does not leave a permanent strain with respect to the external force by selecting an optimal material.

In the microstructure of the present embodiment described above, the bottom surface shape of the cone-shaped protrusion 12 may be circular or polygonal as described above. However, from the viewpoint of ease of molding or mold production, A quadrangle (see FIGS. 2 and 3) is preferable.
Moreover, in this embodiment, although the base 10 has comprised flat form (refer FIGS. 1-3), it is not limited to this, Curve shape may be sufficient.

In addition, in this embodiment, although the base 10 and the cone-shaped protrusion 12 are integrally molded, it is not limited to this, It is also possible to form both members separately.
Furthermore, it is also possible to add a substrate (not shown) and install the microstructure of the present invention including a base and a functional layer on the substrate.
Moreover, it is preferable that the cone-shaped projections 12 have a congruent relationship with each other, but the present invention is not limited to this, and the shape of the cone-shaped projections 12 may be varied depending on the intended function expression.

FIG. 4 is a schematic explanatory view showing a microstructure according to the fourth embodiment of the present invention, and FIG. 5 is a schematic explanatory view showing a microstructure according to the fifth embodiment of the present invention.
In the embodiment shown in FIGS. 1 and 3, the base 10 is not exposed between the cone-shaped protrusions 12 or in the vicinity of the edge, but is exposed as shown in FIG. Furthermore, it is also possible to provide a recess between the conical projections 12.
In such an embodiment, as shown in FIG. 4, assuming a virtual plane B ′ passing through the bottom of each recess, a plane B partitioned by sequentially connecting the bottoms of a plurality of recesses surrounding one fine protrusion. A part of 'is defined as the bottom surface of the fine protrusion.
Further, in the embodiment in which the base portion 10 is not exposed but the root portion of each fine protrusion has a curved surface, as shown in FIG. 5, a surface B ′ passing through the bottom between adjacent root portions is assumed, and one fine portion is assumed. A part of the surface B ′ partitioned by sequentially connecting the bottoms between the plurality of root portions surrounding the protrusion is defined as the bottom surface of the fine protrusion.
In addition, when providing such an exposed part and a recessed part, it is preferable to coat | cover a functional layer also to these parts.

<Material>
Next, the material of the microstructure of the present invention will be described.
First, the material of the base 10 and the cone-shaped projections 12 that are fine projections is not particularly limited. For example, acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate, triacetyl cellulose, and diacetyl cellulose. And cellulose resins such as styrene resin, vinyl chloride resin, polynorbornene, polyethylene naphthalate, cycloolefin copolymer resin or amorphous nylon resin, and copolymers and polymer alloys thereof.

  When the above-mentioned microstructure is used for light transmission, for example, for a window glass or other transparent member, the circumscribed circle diameter Db and the top distance P are set to constant values of 380 nm or less, respectively, and the base material is used. Is preferably an acrylic resin, polycarbonate resin, polyethylene terephthalate resin, styrene resin, polynorbornene resin, cycloolefin copolymer resin, or amorphous nylon resin.

  In addition, in the above-mentioned resins, various kinds of rubbers for improving impact resistance, ultraviolet absorbers for improving weather resistance, and other modifiers such as antioxidants, colorants, flame retardants and antistatic agents are used. Additives can be included.

Next, the material of the functional layer 20 includes a compound having silicon, and the functional layer 20 is formed by chemically bonding this compound to the surface of the cone-shaped protrusion 12.
Typical examples of the compound having silicon include silane compounds, particularly fluorine-containing silane compounds, and commercially available silane compounds, preferably commercially available fluorine-containing silane compounds, can be widely used.
The silane compound has water repellency, but by further including fluorine in the chemical structure, the surface can be reduced in energy and a high static contact angle can be realized. Moreover, by being a silane compound, the adhesiveness with a cone-shaped convex part and a base part can be improved, and it becomes possible to improve durability of various performances, such as water repellency.

The silane compound is not particularly limited as long as it has a group that becomes a silanol group by hydrolysis, and examples thereof include a chlorosilane compound, an alkoxysilane compound, an acyloxysilane compound, and a silazane compound.
Further, the number of the above groups per molecule is not particularly limited, and a plurality of groups may be present at both ends or in the middle of the molecule.
However, an alkoxysilane compound is particularly preferable in consideration of safety of by-products, environmental impact, and cost. Moreover, any of a monofunctional, bifunctional, and trifunctional compound may be sufficient, and a mixture thereof may be sufficient, but it is more preferable to use a trifunctional compound in consideration of adhesion to the base.

Examples of the compound having at least one group that becomes a silanol group by hydrolysis in the molecule include the following.
_{CH 3 - (CH 2 -CH 2} -CH 2 -O) n-Si (OCH 3) 3: n = 2~40
_{CH 3 - (CH 2 -CH 2} -CH 2 -O) n-Si (OCH 2 CH 3) 3: n = 2~40
_{{CH 3 - (CH 2 -CH} 2 -CH 2 -O) n} 2 -Si (OCH 3) 2: n = 2~40
_{{CH 3 - (CH 2 -CH} 2 -CH 2 -O) n} 3 -SiOCH 3: n = 2~40
_{CH 3 - (CH 2) n} -Si (OCH 3) 3: n = 8~100
_{CH 3 - (CH 2) n} -Si (OCH 2 CH 3) 3: n = 8~100
_{{CH 3 - (CH 2)} n} 2 -Si (OCH 3) 2: n = 8~100
_{{CH 3 - (CH 2)} n} 2 -Si (OCH 2 CH 3) 2: n = 8~100
_{{CH 3 - (CH 2)} n} 3 -SiOCH 3: n = 8~100
_{{CH 3 - (CH 2)} n} 3 -SiOCH 2 CH 3: n = 8~100
_{CH 3 - (CH 2 -CH 2} -CH 2 -O) n-SiCl 3: n = 2~40
_{{CH 3 - (CH 2 -CH} 2 -CH 2 -O) n} 2 -SiCl 2: n = 2~40
_{{CH 3 - (CH 2 -CH} 2 -CH 2 -O) n} 3 -SiCl: n = 2~40
_{CH 3 - (CH 2) n} -SiCl 3: n = 8~100
^{_{{CH 3 - (CH 2)}} n} 2 -SiCl 2: n = 8~100
_{{CH 3 - (CH 2)} n} 3 -SiCl: n = 8~100

Further, among the compounds having at least one group that becomes a silanol group by hydrolysis in the molecule, examples of the compound having a perfluoroalkyl group or a perfluoroether group include the following.
_{CF 3 - (CF 2 -CF 2} -CF 2 -O) n-Si (OCH 3) 3: n = 2~40
_{CF 3 - (CF 2 -CF 2} -CF 2 -O) n-Si (OCH 2 CH 3) 3: n = 2~40
_{{CF 3 - (CF 2 -CF} 2 -CF 2 -O) n} 2 -Si (OCH 3) 2: n = 2~40
_{{CF 3 - (CF 2 -CF} 2 -CF 2 -O) n} 3 -SiOCH 3: n = 2~40
_{CF 3 - (CF 2) n} -Si (OCH 3) 3: n = 8~100
_{CF 3 - (CF 2) n} -Si (OCH2CH 3) 3: n = 8~100
_{{CF 3 - (CF 2)} n} 2 -Si (OCH 3) 2: n = 8~100
_{{CF 3 - (CF 2)} n} 2 -Si (OCH 2 CH 3) 2: n = 8~100
_{{CF 3 - (CF 2)} n} 3 -SiOCH 3: n = 8~100
_{{CF 3 - (CF 2)} n} 3 -SiOCH 2 CH 3: n = 8~100
_{CF 3 - (CF 2 -CF 2} -CF 2 -O) n-SiCl 3: n = 2~40
_{{CF 3 - (CF 2 -CF} 2 -CF 2 -O) n} 2 -SiCl 2: n = 2~40
_{{CF 3 - (CF 2 -CF} 2 -CF 2 -O) n} 3 -SiCl: n = 2~40
_{CF 3 - (CF 2) n} -SiCl 3: n = 8~100
_{{CF 3 - (CF 2)} n} 2 -SiCl 2: n = 8~100
_{{CF 3 - (CF 2)} n} 3 -SiCl: n = 8~100

In order to impart super hydrophilicity to the microstructure, a hydroxyl group, a carboxyl group, an amino group, an ammonium group, a —COONa group, a —SO ₃ Na group, a —SO ₃ NH ₄ group, a —COONH ₄ group, It is preferable to have a polar group according to a —PO ₃ Na ₂ group or —PO ₃ (NH ₄ ) ₂ group and a combination thereof.

Next, the manufacturing method of the microstructure according to the present invention will be described.
As described above, the microstructure manufacturing method of the present invention is a method for manufacturing the predetermined microstructure, and includes the following steps.
(A) A step of molding a resin base having the cone-shaped projections (B) A step of subjecting the base to an oxidation treatment or a discharge treatment to introduce OH groups onto the surface of the cone-shaped projections (C) The projections A process of forming a functional layer by coating a compound containing silicon element on the surface

Here, the method for creating the base portion having the cone-shaped convex portion in the step (A) is not particularly limited, and the following method, which is a general method for creating a fine concavo-convex structure, can be used.
First, a silicon or aluminum mold having a desired structure is created by lithography using an electron beam, and then a photocurable resin or a thermosetting resin is applied on the mold coated with a release agent as a nanoimprint. The desired structure is transferred to the resin by pressing it through the substrate at an arbitrary pressure for a predetermined time.
At this time, when using a photo-curable resin, a substrate having UV transparency such as a quartz plate is used and cured by irradiating the resin with UV. Moreover, when using a thermosetting resin, it is hardened by heating using a metallic substrate with good thermal conductivity.
Note that the mold and the substrate are not limited to a flat plate shape, and it is also possible to use a roll shape having improved continuity or a large area.

The step (B) corresponds to the pretreatment of the coating of the silicon-containing compound in the step (C), and is not particularly limited as long as OH groups can be introduced into the surface of the cone-shaped convex portion. A treatment method selected from a discharge treatment, a flame treatment, a plasma discharge treatment, a glow discharge treatment, and an ozone treatment, and more preferably the following corona discharge treatment, particularly in view of simplicity of operation.
This treatment removes deposits such as mold release agents that have previously adhered to the surface of the base having a fine structure, and includes silicon-containing compounds represented by silane compounds, hydroxyl groups and amino groups that can be covalently bonded to silicon-containing compounds. A polar group such as a system can be more reliably introduced.

<Corona discharge treatment>
Here, corona discharge treatment is a type of gas discharge, in which gas molecules are ionized to exhibit conductivity, and the surface of an object such as a film is activated by the ion flow, such as EC treatment, discharge treatment, etc. As a widely used technology.
The gas used for the discharge treatment may be air, but a special mixed gas such as nitrogen, carbon dioxide, ammonia gas, argon gas and helium gas may be used as long as oxygen is contained in an amount of 0.1 vol% or more.
By containing 0.1 vol% or more of oxygen, ozone radicals can be generated efficiently, and as a result, deposit removal and introduction of the polar group are facilitated.

In addition, the high frequency applied to the electrode during the corona discharge treatment is not particularly limited, and a corona that is generated by applying a voltage to the electrode from a conventionally known sinusoidal high frequency power generator is used for the object. What is necessary is just to process the surface of a certain cone-shaped protrusion.
Specifically, corona discharge degree is preferably set to 1~20W / cm ^2, and more preferably be 2~10W / cm ^2.
Also, corona discharge amount is preferably set to 100~2000W · min / ^{m 2,} and more preferably be 300~900W · min / ^{m 2.} When the amount of corona discharge is less than 100, the surface treatment is insufficient and the adhesion of the silicon-containing compound may not be exhibited. If it exceeds 2000, the molecular weight of the resin, the destruction of the structure, and the durability of various performances due to embrittlement may occur, which is not preferable.

  In addition, by performing such treatment as corona discharge treatment, as described above, the wetting tension on the surface of the cone-shaped protrusion can be set to 50 to 70 mN / m.

<Oxidation treatment>
・ Immersion method As a surface modification method for activating the film surface, as described in JP-A-2005-88578, a method of immersing in a solution such as an alkali, an acid, or a surfactant and various solvents is used. Can be applied.
-UV irradiation method Moreover, as described in Unexamined-Japanese-Patent No. 2007-182503, the method of irradiating an excimer ultraviolet-ray or a low-pressure ultraviolet-ray to the film surface is applicable.

  Next, the step (C) is a step of forming a functional layer by coating the silicon-containing compound on the surface of the cone-shaped protrusion that has been treated as described above. After coating, heat treatment is performed to form a functional layer.

<Application method>
The method for applying the silicon-containing compound is not particularly limited. Spray coating, bar coater coating, spin coating, dip coating, roll coating, gravure coating, curtain flow coating, bar coating, blade coating , Methods used in normal coating operations such as die coating, reverse roll coating, and slit coating.
At this time, the silicon-containing compound may be diluted to various concentrations with various solvents in order to facilitate coating or to adjust the film thickness of the functional layer. As the solvent, specifically, perfluoroether, hydrofluoroether, perfluoropolyether, hydrofluoropolyether and the like can be used.

<Heat treatment method>
There is no limitation as long as a chemical bond, typically a covalent bond, can be generated between the silicon-containing compound and the cone-shaped protrusion, and ordinary heating / heating treatment is sufficient.
The atmosphere for performing the heat treatment may be either air or an inert gas such as argon gas.
The heat treatment temperature is not particularly limited as long as it is a temperature at which the base, the substrate or the cone-shaped projections are not thermally deformed or deteriorated, but is preferably about 80 to 130 ° C. The heat treatment time is preferably about 5 minutes to 120 minutes, although it depends on the heat treatment temperature.

Although the thickness of the functional layer formed is not specifically limited, 1-20 micrometers is preferable.
If it is less than 1 μm, it is difficult to obtain the effect of increasing the reactivity with the silicon-containing compound. On the other hand, if it exceeds 20 μm, the functional layer may be cracked, which is not preferable from the viewpoint of layer strength.
In addition, the film in which the cured film containing inorganic compound fine particles was formed is often used as an anti-glare film.

In addition, in the manufacturing method of this invention, you may start a silicon | silicone containing compound coating | cover ((C) process) to a cone-shaped convex part during the process at (B) process. In this case, it is easy to suppress the wetting tension on the surface of the protrusion and to ensure the adhesion between the cone-shaped convex part (or base part) and the functional layer, and in both steps (B) and (C). Productivity can be improved because the total time required can be shortened.
On the other hand, the coating of the silicon-containing compound (step (C)) may be started at the end of the treatment in step (B). In this case, the excessive wetting tension on the surface of the protrusion is suppressed, and the decrease in the molecular weight of the resin constituting the cone-shaped convex portion (or base), the destruction of the fine structure, and the deterioration in the durability of various performances due to embrittlement are prevented. Easy to do.
Further, in the step (C), (1) a step of immersing the surface of the fine protrusion in a compound containing silicon or a solution thereof, or (2) applying a compound containing silicon or a solution thereof on the surface of the fine protrusion. A process may be included.
Specifically, a compound containing silicon or a solution thereof may be applied to the surface of the cone-shaped convex portion. According to these methods, the silicon-containing compound can be coated with a relatively simple apparatus without introducing a special apparatus for processing, which is advantageous in terms of production / productivity and cost.

As described above, the fine structure of the present invention obtained through the treatment as described above preferably has a dynamic friction coefficient of 0.05 to 0.25, and more preferably 0.05 to 0.20.
By having such a dynamic friction coefficient, excellent fracture resistance is expressed over a long period of time, and good durability can be realized.
Moreover, the fine structure obtained by the production method of the present invention is coated with a functional layer having functions such as super water repellency and super hydrophilicity at a high density, and has excellent durability.
This is because pretreatment removes deposits such as a release agent previously adhered to the surface of the base having a fine structure, so that a silicon-containing compound, typically a hydroxyl group or amino group to which a silane compound can be covalently bonded. This is because the functional group-containing compound is coated at a higher density because polar groups such as are introduced at a higher density.

Next, the automobile part of the present invention will be described.
The automobile part of the present invention is constituted by using the fine structure of the present invention described above. Specifically, by utilizing the water repellency and antifouling property, the window shield, the rear window, the side Water repellent film and antifouling film applicable to the outside such as transparent openings such as windows and roofs, side mirrors, light parts, camera lens parts, camera lens cover parts, wheels, body parts, bumper parts, etc. Taking advantage of the properties and anti-fogging properties, mention may be made of the above-mentioned transparent opening, the light part, the camera lens part, the interior side of the camera lens cover part, the hydrophilic film and the anti-fog film applicable to the rearview mirror it can.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples. In addition, in the Example shown below, the evaluation test method of various physical properties is as follows.

(1) Stationary contact angle: Using a contact angle meter (CA-A type: manufactured by Kyowa Interface Chemical Co., Ltd.), make a 6 μl water droplet on the needle tip at room temperature and let it touch the surface of the sample to be measured. I made it. The angle between the droplet generated at this time and the surface was measured, and five points were measured by a three-point plot (θ / 2 direction), and the average value of these values was defined as the static contact angle.
(2) Endurance contact angle: Campus cloth was installed on a 30 × 30 mm indenter, and after sliding back and forth 1000 times on the surface of the base material, the static contact angle with respect to pure water was measured at five points using the above-mentioned method for measuring the static contact angle. The average value of these values was defined as the durable contact angle.
(3) Coefficient of dynamic friction: Using a surface property tester (HEIDEN Type 14W: manufactured by Shinto Chemical Co., Ltd.), fixing a PET film to a 20 × 20 mm acrylic indenter, and installing it on a 50 × 100 mm sample, Measurements were made at a feed rate of 100 mm / min, a feed length of 70 mm, and a load of 0.1 kgf / cm ² .
(4) Wetting tension measurement after corona treatment: After the corona treatment, a wetting tension test liquid mixture (manufactured by Wako Pure Chemical Industries, Ltd.) No. After adhering 50-73 to 5 cm with a rolling pin, the sample was allowed to stand for 2 seconds, and the wetting tension of the reagent with no visual change was taken as the measured value.

<Specification of one microstructure>
Table 1 shows the specifications of one microstructure used in the following examples.

Example 1
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 1, the fine structure 1 having a frustum shape with P of 100 nm, Dt of 30 nm, and H of 200 nm is arranged in a hexagonal close-packed state (Db: 100 nm). Was formed on one side.
Using a corona discharge treatment apparatus, the microstructure surface was subjected to corona discharge treatment under the following <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of the following <compound 1> was gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

[Compound]
<Compound 1>
_{CF 3 - (CF 2 -CF 2} -CF 2 -O) n-Si (OCH 2 CH 3) 3: n = 2~40
<Compound 2>
_{(CH 3 CH 2 O) 3} Si-O- (CF 2 -CF 2 -CF 2 -O) n-Si (OCH 2 CH 3) 3: n = 2~40
<Compound 3>
_{(CH 3 CH 2 O) 3} Si-O- (CH 2 -O) -COONa: n = 2~40

[Corona discharge treatment conditions]
<Condition 1>
In air, humidity 40%, 25 ° C., radiation amount 480 W · min / m ² , discharge degree 14.4 W / cm ²
<Condition 2>
₁ vol% O ₂ /99.9 vol% N ₂ , humidity 40%, 25 ° C., radiation amount 480 W · min / m ² , discharge degree 14.4 W / cm 2
<Condition 3>
In air, humidity 40%, 25 ° C., radiation amount 1600 W · min / m ² , discharge 48 W / cm ²

( Reference Example 2 )
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 1, the fine structure 2 in the shape of a frustum having P of 150 nm, Dt of 40 nm, and H of 200 nm is arranged in a hexagonal dense state (Db: 150 nm). Was formed on one side. Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

( Reference Example 3 )
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 1, the fine structure 3 in the shape of a frustum having P of 200 nm, Dt of 60 nm, and H of 200 nm is arranged in a hexagonal close-packed state (Db: 200 nm). Was formed on one side. Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

Example 4
The same procedure as in Example 1 was carried out except that <Compound 1> was changed to <Compound 2> to produce the microstructure of this Example.

(Example 5)
The same operation as in Example 1 was performed except that <Condition 1> was changed to <Condition 2>, and the microstructure of this Example was created.

(Example 6)
The same procedure as in Example 1 was performed, except that <Condition 1> was changed to <Condition 2> and <Compound 1> was changed to <Compound 2>, thereby producing a microstructure of this Example.

( Reference Example 7 )
The same operation as in Example 1 was performed except that the corona discharge treatment was not performed, and the microstructure of this example was created.

( Reference Example 8 )
The same operation as in Example 1 was performed except that <Condition 1> was changed to <Condition 3>, and the microstructure of this example was created.

Example 9
The same procedure as in Example 1 was carried out except that <Compound 1> was changed to <Compound 3>, and the microstructure of this Example was produced.

(Example 10)
The same procedure as in Example 1 was performed, except that <Condition 1> was changed to <Condition 2> and <Compound 1> was changed to <Compound 3>, thereby producing a microstructure of this Example.

(Comparative Example 1)
For Example 1, a flat mold was used in place of the mold created by the electron beam drawing apparatus, and the same operation was performed except that the corona discharge treatment was not performed, and the microstructure of this comparative example was created. .

(Comparative Example 2)
The same operation as in Example 1 was performed except that a flat mold was used instead of the mold created by the electron beam drawing apparatus, and a microstructure of this comparative example was created.

(Comparative Example 3)
The same operation as in Example 1 was performed except that a flat mold was used instead of the mold created by the electron beam drawing apparatus, the corona discharge treatment was not performed, and <compound 1> was changed to <compound 3>. The microstructure of this comparative example was made.

(Comparative Example 4)
The same operation as in Example 1 was performed except that a flat mold was used instead of the mold created by the electron beam drawing apparatus, and <Compound 1> was changed to <Compound 3>. Created a structure.

(Comparative Example 5)
For Example 1, the same operation was performed except that the corona discharge treatment was not performed and the silane compound was not applied, and the microstructure of this comparative example was created.

Table 2 shows the results of measurement performed on the obtained microstructure by the above method.
As a result, in Examples 1, 4 to 6 and Reference Examples 2 , 3 , 7 , and 8 , which are within the scope of the present invention, the static contact angle with water is 134 ° or more, and water adhesion hardly occurs. It became a thing. In particular, in Examples 1, 4, 5 and Reference Examples 2 , 3 , the durable contact angle is also 145 ° or more. This is because it has a fine structure and the adhesion between the base and the silane compound is good by corona discharge treatment and optimization of the silane compound. On the other hand, since Comparative Examples 1 and 2 are not fine structures, the water repellency is low.
In Examples 9 and 10, the static contact angle with water was 10 ° or less, and high antifogging properties were exhibited. This is because it has a fine structure and the adhesion between the base and the silane compound is good by corona discharge treatment and optimization of the silane compound. On the other hand, since Comparative Examples 3 and 4 are not fine structures, the hydrophilicity is low, and thus the antifogging property is also low.
In Examples 1, 4 to 6, Reference Examples 2, 3, 7, 8, and Examples 9 and 10 , H / P is in the range of 0.2 to 10 for durability (durable contact angle). It is thought that it has contributed. In Examples 1, 4 to 6, 9, 10, and Reference Examples 2 and 3 , the wet tension of the fine protrusions after the discharge treatment is in the range of 50 to 70 mN / m. Corner) and durability (endurance contact angle).

<Specifications of other microstructures>
Table 3 shows the specifications of other fine structures used in the following examples, and Table 4 shows the results of measurement by the above method for the other fine structures.
Another microstructure shown in the present embodiment is called a moth-eye type in which a projection tip and a root are formed by a curved surface. Note that <Condition 1> and <Compound 1> shown in Table 4 are the same as those described in the one microstructure described above, and thus detailed description thereof is omitted in this example.

( Reference Example 11 )
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 3, a molded body in which the microstructure 4 having P of 100 nm, Dt of 35 nm, and H of 200 nm was arranged in one side in a hexagonal fine state (Db: 100 nm) was produced.
Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

( Reference Example 12 )
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 3, a molded body in which the microstructure 5 having P of 200 nm, Dt of 75 nm, and H of 2000 nm was arranged in one side in a hexagonal fine state (Db: 200 nm) was produced.
Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

(Example 13)
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 3, a molded body in which the microstructure 6 having P of 200 nm, Dt of 10 nm, and H of 2000 nm was arranged in one side in a hexagonal fine state (Db: 200 nm) was produced.
Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

(Example 14)
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 3, a molded body in which the microstructure 7 having P of 200 nm, Dt of 5 nm, and H of 2000 nm was arranged in one side in a hexagonal fine state (Db: 200 nm) was produced.
Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

(Example 15)
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. As a result, as shown in Table 3, a molded body in which the microstructure 8 having P of 200 nm, Dt of 5 nm, and H of 2200 nm was arranged in one side in a hexagonal fine state (Db: 200 nm) was produced.
Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

( Reference Example 16 )
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 3, a molded body in which the microstructure 9 having P of 100 nm, Dt of 45 nm, and H of 200 nm was arranged in one side in a hexagonal fine state (Db: 100 nm) was produced.
Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 1> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.

As a result of measuring the obtained other fine structures by the above method, as shown in Table 4, in Examples 13 to 15 and Reference Examples 11 , 12 , and 16 that are within the scope of the present invention, And the static contact angle was 143 ° or more, and water adhesion hardly occurred. In any of Examples 13 to 15 and Reference Examples 11 , 12 , and 16 , the durable contact angle is 143 ° or more. This is because it has a fine structure and the adhesion between the base and the silane compound is good by corona discharge treatment and optimization of the silane compound.

( Reference Example 17 )
Using a mold created with a commercially available electron beam lithography system, UV-curing acrylic resin (Toa Gosei Co., Ltd. PAK01) is poured between the mold and the PET film as the base material, and ultraviolet rays are irradiated from the PET film side. Thus, as shown in Table 3, a molded body in which the microstructure 10 having P of 100 nm, Dt of 40 nm, and H of 200 nm was arranged in one side in a hexagonal fine state (Db: 100 nm) was produced.
Using a corona discharge treatment apparatus, the surface of the microstructure is subjected to corona discharge treatment under <condition 1>, and a 0.1% hydrofluoroether (3M Novec HFE-7100) solution of <compound 2> which is a silane compound is gravured on the surface. It was applied to a thickness of 30 μm using a coater, and dried in a drying oven at 120 ° C. for 5 minutes to prepare a fine structure.
As a result of measuring the obtained other fine structure by the above method, as shown in Table 4, in Examples 13 to 15 and Reference Examples 11 , 12 , 16 , and 17 , which are within the scope of the present invention, In addition, the static contact angle with water was 142 ° or more, and water adhesion hardly occurred. In any of Examples 13 to 15 and Reference Examples 11 , 12 , 16 , and 17 , the durable contact angle is 140 ° or more. This is because it has a fine structure and the adhesion between the base and the silane compound is good by corona discharge treatment and optimization of the silane compound.
In Examples 13 to 14 and Reference Examples 11 , 12 , 16 , and 17 , H / P in the range of 0.2 to 10 is considered to contribute to durability (durable contact angle). Further, in Examples 13 to 15 and Reference Examples 11 , 16 , and 17 , the wetting tension of the fine protrusions after the discharge treatment is in the range of 50 to 70 mN / m. In Examples 13 and 15, and Reference Examples 11 and 12 , A dynamic friction coefficient in the range of 0.05 to 0.25 is considered to contribute to the adhesion (static contact angle) and durability (durable contact angle) of the compound. Similarly, in Reference Examples 16 and 17 , the relationship between the top diameter Dt and the top-to-top distance P is Dt ≧ 0.4P, which reduces the contact area between the surface of the microstructure and water and is high. This is thought to contribute to obtaining a static contact angle.

The present invention is not limited to the embodiment described above. For example, in the above-described embodiment, the fine protrusions that are the cone-shaped protrusions have been described as examples, but it is added that the present invention is not limited to the form.
The present invention is not limited to the above-described embodiments, and the following modifications can be made.

10 Base 12 Fine projection (conical projection)
20 Functional layer Db circumscribed circle diameter Dt bottom diameter P top distance P

Claims (15)

A resin base having a plurality of fine protrusions that are two-dimensionally continuous, and a microstructure having a functional layer covering the fine protrusions,
The microprotrusions have been subjected to corona discharge treatment or plasma treatment, and the wetting tension of the microprotrusion surface immediately after the treatment is 50 to 70 mN / m,
The fine projection is formed of a cone-shaped convex portion, and the top portion of the cone-shaped convex portion forms a circular or polygonal top surface, and is adjacent to the diameter Dt of a circle circumscribing the circular top surface or the polygonal top surface. And the distance P between the tops of the cone-shaped convex portions to satisfy the relationship of Dt ≧ 0.4P,
The distance P between the tops is 380 nm or less, the diameter Dt of the circumscribed circle is 30 nm or less,
The fine structure according to claim 1, wherein the functional layer is formed by chemically bonding a compound containing silicon directly to a surface of the fine protrusion. The fine structure according to claim 1 , wherein the aspect ratio H / P is 0.2 to 10 where H is the height of the fine protrusion. The fine structure according to claim 1 or 2 , wherein a coefficient of dynamic friction on a surface of the fine structure is 0.05 to 0.25. The microstructure according to any one of claims 1 to 3 , wherein the silicon-containing compound has a group that becomes a silanol group by hydrolysis. The microstructure according to any one of claims 1 to 4 , wherein the compound containing silicon has a perfluoroalkyl group or a perfluoroether group. The compound containing silicon is a hydroxyl group, a carboxyl group, an amino group, an ammonium group, a —COONa group, a —SO ₃ Na group, a —SO ₃ NH ₄ group, a —COONH ₄ group, a —PO ₃ Na ₂ group, and a —PO. _{3 (NH 4)} microstructure according to any one of claims 1 to 5, characterized in that at least one polar group selected from the group consisting of ₂ groups. A group in which the base is made of acrylic resin, polycarbonate resin, polyester resin, cellulose resin, styrene resin, vinyl chloride resin, polynorbornene resin, cycloolefin polymer resin, cycloolefin copolymer resin, and amorphous nylon The microstructure according to any one of claims 1 to 6 , wherein the microstructure is at least one selected from the group consisting of a resin, a copolymer, and a polymer alloy. The distance P between the tops of the adjacent fine protrusions is a constant value of 380 nm or less, and the base is an acrylic resin, polycarbonate resin, polyethylene terephthalate resin, styrene resin, polynorbornene resin, cycloolefin polymer resin, The microstructure according to any one of claims 1 to 6 , wherein the microstructure is a transparent resin comprising a cycloolefin copolymer resin or amorphous nylon. An automobile part comprising the fine structure according to any one of claims 1 to 8 . A method for producing the microstructure according to any one of claims 1 to 8 ,
(A) a step of molding a resin base having the fine protrusions, (B) a step of subjecting the base to oxidation treatment or discharge treatment to introduce polar groups on the surface of the fine protrusions, and (C) the fine portions A method for manufacturing a microstructure, comprising a step of forming a functional layer by coating a surface of a protrusion with a compound containing silicon. The method for manufacturing a microstructure according to claim 10 , wherein the discharge treatment is a corona discharge treatment or a plasma treatment. The method for producing a microstructure according to claim 11 , wherein oxygen is contained in the introduced gas in the corona discharge treatment or the plasma treatment at a ratio of 0.1 vol% or more. The method for manufacturing a microstructure according to claim 10 , wherein the step (C) is started after the end of the step (B). The method for manufacturing a microstructure according to claim 10 , wherein the step (C) is started during the execution of the step (B). The step (C) includes (1) a step of immersing the surface of the fine protrusion in a compound containing silicon or a solution thereof, or (2) a step of applying a compound containing silicon or a solution thereof on the surface of the fine protrusion. The method for manufacturing a fine structure according to any one of claims 10 to 14 , wherein:

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