JP6600809B2 - Base material and equipment using the base material - Google Patents

Description

The present invention relates to a base material and a device using the base material. In particular, the present invention relates to a base material that easily evaporates moisture and the like and an apparatus using the base material.

  In the evaporator of the conventional refrigeration equipment and air conditioning equipment, when the surface temperature of the fin in the evaporator becomes a negative temperature, frost forms on the surface of the fin. As a result, the amount of air passing between the fins is reduced, and the cooling capacity of the evaporator is reduced.

  In addition, security cameras and in-vehicle cameras used outdoors are subject to condensation on the camera in rainy weather or cold areas, and the camera performance is degraded.

  In order to solve the above problems, a technique is known in which a large number of uneven portions are formed on the surface of the evaporator fin to absorb heat, and a water repellent film is formed on the uneven portions (Patent Document). 1). This can prevent generation of condensed water and frost on the fin surface. In addition, as the water-repellent coating of Patent Document 1, a fluorine-based or silicone-based paint is used.

JP 2013-36733 A

  However, the technique disclosed in Patent Document 1 has the following problems. This will be described with reference to FIG.

  FIG. 6 is a cross-sectional view showing a water-repellent substrate 22 produced by a conventional method. The water-repellent substrate 22 includes a base 23, protrusions 24, and a hydrophobic coating 25.

  There are innumerable protrusions 24 from the surface of the base 23. The hydrophobic coating 25 is present on the surfaces of the base 23 and the protrusions 24 in the form of hair. Moreover, the cross-sectional width dimension D of the protrusion 24 is formed in the range of 75 to 100 μm. The gap between the projections 24 between the projections 24 is also the same size.

  For this reason, condensed water adheres between the protrusions 24, and the condensed water spreads and grows into large water droplets, or grows from condensed water to frost in a low temperature region. As a result, the cooling performance of the evaporator is degraded. Increasing the gap can prevent the condensation water from adhering, but the temperature drops and water is produced by frost.

  This invention solves the said conventional subject, and makes it a subject to provide the base material which can prevent condensed water and frost formation, and the apparatus using the base material.

  In order to achieve the above object, a plurality of quadrangular pyramid-shaped protrusions located on at least one surface of the base, and a distance between tip portions of the plurality of protrusions is 5 nm or more and less than 10 nm A substrate is used. A device having the above substrate is used.

  In the base material of the present invention, water droplets and frost grow only on the tips of the protrusions subjected to the hydrophilic treatment. Therefore, water droplets and frost separate from the base material due to their own weight. Since frost formation and dew condensation water can be removed without using a heating device, it is possible to prevent the cooling performance of the evaporator from being lowered and to prevent the camera lens and the member made of resin from being fogged.

(A) The figure which shows the base material in embodiment of this invention, (b) Sectional drawing of the base-material surface in embodiment of this invention The figure which shows the production | generation process of the condensed droplet on the base-material surface in embodiment of this invention (A) The figure which shows the base material in the form of Example 3, (b) Sectional drawing of the base-material surface in the form of Example 3 Sectional drawing of the test apparatus in dew condensation water evaluation and frost formation evaluation in Examples and Comparative Examples (A) The figure which shows the example of application of Example 1 of this invention, (b) The figure which shows the example of application of Example 4 of this invention Sectional drawing of the conventional base material in the form of patent document 1

  Hereinafter, the base material 1 which concerns on embodiment of this invention is demonstrated. Fig.1 (a) is a perspective view of the base material 1, FIG.1 (b) shows sectional drawing which described the detail of the dotted line part of the base material 1 surface of Fig.1 (a). The material of the base material 1 is resin or metal.

  The substrate 1 has a base portion 2 and a plurality of protrusions 3 having a trapezoidal cross section and a quadrangular pyramid shape, and has a hydrophilic portion 4 at the tip of the protrusion 3. The protrusion 3 is located at least on the surface of one surface of the base 2. There may be a protrusion 3 on the other surface of the base 2.

  The boundary between the base portion 2 and the protrusion portion 3 corresponds to the boundary of presence / absence of processing for generating the protrusion portion 3. A method of generating the protrusion 3 will be described below in <Generation of the base material 1 and the protrusion 3>.

  Further, in the base material 1, the surface of the base portion 2 and the projection portion 3 is subjected to water repellent treatment, and only the hydrophilic portion 4 corresponding to the tip of the projection portion 3 is subjected to hydrophilic treatment. By setting the distance d between the protrusions 3 shown in FIG. 1B to 5 to 10 nm, condensed water grows only at the hydrophilic portion 4 and becomes a material that can prevent dew condensation and frost formation.

  Here, the length L ′ of the tip of the protrusion 3 is preferably 10% or more and 25% or less with respect to the length L of the protrusion 3. If it is less than 10% or less, hydrophilic treatment of only the tip portion becomes difficult. If it is greater than 25%, the area where condensed water is adsorbed increases, and the effect of preventing condensed water and frost formation is reduced.

  In addition, the distance between the protrusions 3 here indicates the distance between the centers of the protrusions 3.

  Further, the angle θ is an angle with respect to the vertical direction. As shown in FIG. 1B, in the cross-sectional view of the substrate 1 in the direction parallel to the vertical direction, it is an angle formed by the upper end portion of the side surface of the protrusion 3 and the vertical direction.

<Substrate 1>
The substrate 1 that can be used in the embodiment is characterized in that a plurality of protrusions 3 having a trapezoidal cross section and a quadrangular pyramid are formed on the surface of the substrate 1.

  When the base material 1 is a metal material, an alloy containing aluminum, titanium, or magnesium as a main component is preferable. In this case, it is preferable that the projections 3 are formed by aluminum fine hole machining by an anodic oxidation method. In particular, in the case of an aluminum alloy, not only an anodic oxidation method but also boehmite treatment that reacts with water to form an oxide film is possible, and both are suitable for fine surface unevenness treatment.

  Moreover, if the base material 1 is a resin material, acrylonitrile-butadiene-styrene copolymer synthetic resin (ABS resin) or thermoplastic resin such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), or high rigidity It is preferable to use any one of thermosetting resins such as acrylic resin, epoxy resin, urethane resin, and silicon resin. In this case, the projection 3 is preferably formed by etching or metal paste pattern printing. As a result, fine irregularities can be formed on the surface of the substrate 1.

<Shape of the protrusion 3>
The protrusion 3 is a quadrangular pyramid. Each protrusion length L of the protrusion 3 is 0.1 μm to 10 μm. The distance d between the protrusions 3 is preferably 5 nm to 10 nm.

  When the length L of the protrusion 3 is smaller than 0.1 μm, it is difficult to regularly generate the protrusion 3.

  When the length L of the protrusion 3 is larger than 10 μm, the surface energy attached on the surface of the recess becomes larger than the energy of the condensed droplet moving to the tip when the condensation droplet adheres to the recess between the protrusions 3. Then, the droplet grows on the concave surface.

  Further, when the distance d between the protrusions is smaller than 5 nm, it is difficult to regularly generate the protrusions 3. When the distance d between the protrusions is greater than 10 nm, the condensed droplets adhere to the recesses between the protrusions 3 and the condensed water spreads and grows into large water droplets.

  Further, the protrusion 3 that can be used in the embodiment is preferably formed with an angle θ of less than 90 ° with respect to the vertical direction. Here, the vertical direction indicates the vertical direction regardless of the shape of the substrate 1.

  When the angle θ is less than 90 ° with respect to the vertical direction, even if the water vapor 5 adheres to the protrusion 3, the condensed droplet falls down due to the downward inclination, and the condensed droplet or frost hardly grows in the inclined portion. Become.

  When the angle θ exceeds 90 ° with respect to the vertical direction, the liquid crystal is flat or inclined upward, and thus condensed droplets grow on the entire protrusion or the protrusion recess.

  Condensed droplet growth will be described in the following <Condensed droplet generation process in the protrusion 3>.

<Surface treatment of the protrusion 3 excluding the base portion 2 and the hydrophilic portion 4>
The surface treatment of the protrusion 3 excluding the base portion 2 and the hydrophilic portion 4 that can be used in the embodiment is preferably a water repellent treatment. The reason will be described in the following <Condensed droplet generation process in the protrusion 3>.

  As the water repellent treatment, a method of forming a molecular film made of alkylsilane containing no fluorine bond is preferable. Since the carbon-fluorine bond has a small surface tension, a coating agent having super water repellency can be obtained by including a silane coupling agent containing a carbon-fluorine bond.

  However, such a coating agent is not excellent in abrasion resistance, and there is a problem that the water repellency performance deteriorates as it is used. Therefore, a method of forming a molecular film made of alkylsilane containing no fluorine bond is preferable.

  If this surface treatment is performed, the distance d and the length L between the protrusions 3 can be effective even if not described above.

<Generation process of condensed droplets in the protrusion 3>
A process of generating condensed droplets in the protrusion 3 is shown in FIGS.

  As shown in FIG. 2A, there is water vapor 5 floating around the protrusion 3. These water vapors 5 are likely to be generated from singular points on the surface of the protrusion 3. As a result, as shown in FIG. 2B, the water vapor 5 adheres to the hydrophilic portion 4 at the tip of the protruding portion 3. Next, as shown in FIG. 2 (c), the water vapor 5 grows in situ and becomes condensed droplets 6.

  Hydrophilic treatment is performed on the hydrophilic portion 4, which is the tip of the protruding portion 3, and the protruding portion 3 and the base portion 2 excluding the hydrophilic portion 4 are subjected to water repellent treatment. As a result, the condensed droplet 6 grows only in the hydrophilic portion 4, and the condensed droplet grows into frost in a low temperature environment.

  When the blown air is in contact with the base portion 2 like the fins of the evaporator, the water vapor is easily in contact with the base portion 2 even when natural convection occurs, and the environment is a low temperature environment and a high humidity environment. Condensed droplets depend on the relationship between the water vapor pressure in the air and the saturated vapor pressure when condensed droplets are generated in the minus temperature range, and the surface tension when the surface on which the condensed droplets are generated is water-repellent. The initial radius is about 5 to 10 nm.

  From the above knowledge, it is considered that the initial radius Φ of the condensed condensed droplet 6 shown in FIG. 2C is about 5 nm to 10 nm in the minus temperature environment. By setting the distance d between the protrusions 3 to 5 nm to 10 nm which is the same size as the initial radius Φ, it can be said that condensed droplets are hardly generated even if water vapor adheres to the recesses of the protrusions 3.

  By setting it as the above structure, the base material 1 can prevent dew condensation water and frost formation.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited at all by the following examples.
(Example)
Table 1 shows the configuration of the substrate 1 used in the following examples and comparative examples.

（実施例１、２）
図１（ａ）、図１（ｂ）で示した基材１を作製した。基材１としてアルミ材を使用する。基底部２表面に複数の突起部３を陽極酸化法により生成させる。陽極酸化法はアルミニウムを酸性の電解液中で電気分解して（陽極酸化）微細穴を形成することができる。また、特定条件下において自己組織化により図１に示す突起部３のように規則性構造の生成がされる。生成される突起部３の形状寸法は表１に示す。

(Examples 1 and 2)
The substrate 1 shown in FIGS. 1A and 1B was produced. An aluminum material is used as the substrate 1. A plurality of protrusions 3 are generated on the surface of the base 2 by an anodic oxidation method. In the anodic oxidation method, aluminum can be electrolyzed in an acidic electrolytic solution (anodic oxidation) to form fine holes. In addition, a regular structure is generated like the protrusion 3 shown in FIG. 1 by self-organization under specific conditions. Table 1 shows the shape and size of the generated protrusion 3.

  Next, a water repellent treatment is performed on the entire surface of the substrate 1. The processing method is as follows.

  A silane coupling agent, water, and acetic acid are prepared, and a mixed solution is prepared so that the pH becomes acidic. 12 hours after the preparation of the acidic mixed solution, ethanol was added to the mixed solution to prepare a water repellent treatment solution. After dipping the substrate 1 in this water repellent treatment liquid, the substrate 1 was allowed to stand in a thermostatic bath at 100 ° C. for 1 hour to impart water repellency to the entire surface of the substrate 1.

  Next, in order to produce the hydrophilic portion 4 at the tip of the protrusion, the shape of the protrusion 3 is formed into a trapezoid by finely polishing the tip. Hydrophilicity is imparted to the cut end portion by an etching process to generate the hydrophilic portion 4.

The difference between the first and second embodiments is the size of the protrusion 3.
(Example 3)
The substrate 7 shown in FIGS. 3A and 3B was used. 3 (a) and 3 (b) are diagrams corresponding to FIGS. 1 (a) and 1 (b). The base material 7 has a trapezoidal column shape.

As shown in FIG. 3B, the surface of the substrate 7 has a base portion 8 and a plurality of protrusions 3 having a trapezoidal cross section. Further, the tip of the protrusion 3 has a hydrophilic portion 4.
The base material 7 was produced in the same production method as in Example 1.

(Example 4)
ABS resin is used as the substrate. A plurality of protrusions 3 are generated on the surface of the base 2 by etching. Table 1 shows the shape and size of the generated protrusion 3. For the water repellent treatment, a water repellent treatment solution prepared by the same treatment method as in the example is used. Since the tip of the protrusion has already been subjected to a hydrophilic treatment by etching, after masking the tip so that the hydrophilic agent is not immersed,
The substrate 1 is dipped in the water repellent treatment liquid to impart water repellency.

(Comparative Example 1)
For Comparative Example 1, an untreated base material 1 was produced using an aluminum material as the base material.

(Comparative Example 2)
For Comparative Example 2, an aluminum material is used as the base material 1 and the protrusions 3 are formed, but the surface of the base material 1 is not subjected to water repellency or hydrophilic treatment, as shown in FIGS. 1 (a) and 1 (b). The base material 1 as shown was produced.

(Comparative Examples 3-5)
About Comparative Examples 3-5, the aluminum material was used as the base material 1, and the base material 1 was produced in the same process as Example 1 for the preparation methods.

(Evaluation)
Next, the dew condensation water adsorption evaluation and the frost formation evaluation of the base materials 1 and 7 having the configuration shown in Table 1 were performed. Each evaluation method is as follows.

<Adsorption evaluation of condensed water>
An outline of the test apparatus is shown in FIG. FIG. 4 includes a Peltier element 10, an aluminum plate 11, a resin plate 12, a heat sink 13, a fan 14, a thermocouple 15 in the Peltier element, a thermocouple 16 attached to the sample surface, and the substrate 1.

  The test conditions are as follows. The substrate 1 was placed on the aluminum plate 11 at an atmospheric temperature of 20 ° C. and humidity of 40%, the surface temperature of the substrate 1 was set to 10 ° C., and adsorption of condensed water was observed with a microscope. At that time, the time until the condensed droplets could be visually confirmed on the surface of the substrate 1 was measured. At this time, the acceptance criteria for the suppression of dew condensation water were set to ○ when the measurement time was 30 minutes or longer as compared with the case of Comparative Example 1, and × when the measurement time was less than that.

<Frost evaluation>
The test apparatus shown in FIG. 4 was used as in the case of the condensed water adsorption evaluation. Similar to the condensed water adsorption evaluation, the time until frost formation can be visually confirmed on the surface of the substrate 1 was measured. At this time, the acceptance criterion for frost suppression was evaluated as ◯ when the measurement time was 1 hour or more with respect to the case of Comparative Example 1, and x when the measurement time was less than that.

<Comprehensive judgment of the degree of dew condensation / frosting>
As the acceptance criteria for the degree of dew condensation / frosting inhibition in the present invention, both the dew condensation adsorption adsorption evaluation and the frost formation evaluation were evaluated as “good”. When there was a failure in either, it was set as x.

<Consideration of Table 1>
As is clear from the results from Table 1, the base material 1 according to the example has a greater degree of suppression of dew condensation and frosting than those according to the comparative example, and is excellent in antifogging and defrosting properties. .

<Substrate material>
Comparing Example 1 and Example 4, Example 1 uses aluminum material, and Example 4 uses ABS resin. In any case, the three-dimensional shape has a quadrangular prism, and the hydrophilic portion 4 can be formed by forming the protruding portion 3 and water-repellent treatment, and applying hydrophilic treatment to the tip of the protruding portion 3 to suppress the adsorption of condensed water and frost formation. It was.

<Distance between protrusions and protrusion length>
Comparing Examples 1 to 4 and Comparative Example 4, in Comparative Example 4, the distance between the protrusions is 10 nm, and the protrusion length is 10 μm. For this reason, the condensed droplets adhere to the recesses between the protrusions 3, and the degree of suppression of either condensed water adsorption or frost formation is reduced.

  As a result, the distance between the protrusions 3 is preferably 5 nm or more and less than 10 nm, and the protrusion length is preferably 0.1 μm or more and less than 10 μm.

<End length of protrusion>
Comparing Example 1 and Comparative Example 3, the three lengths L of the protrusions are the same, but in Comparative Example 3, the length L ′ of the tip of the protrusion 3 is 30% of the three lengths L of the protrusions. In Example 1, it is 20%.
Therefore, in the comparative example 3, the area which condensed water adsorb | sucks became large, and the suppression degree of any dew condensation water adsorption | suction and frost formation became small.

  As a result, the tip length L ′ of the protrusion is preferably 10% or more and 25% or less of the length L ′ of the tip of the protrusion 3 with respect to the length L of the protrusion 3.

<An angle at which the protrusion is formed>
Comparing Examples 1 to 4 and Comparative Example 5, in Comparative Example 5, the angle θ at which the protrusion 3 is formed exceeds 90 ° with respect to the vertical direction. Therefore, condensed droplets grew not only on the hydrophilic portion of the protrusion 3 but also on the entire protrusion 3, and the degree of suppression of either condensed water adsorption or frost formation was reduced.

  As a result, the angle θ at which the protrusion is formed is preferably less than 90 ° with respect to the vertical direction regardless of the shape of the substrate.

<Surface treatment>
When Examples 1 to 4 and Comparative Examples 1 and 2 are compared, in Comparative Example 2, the portion excluding the tip of the protrusion 3 and the base 2 are not subjected to water repellent treatment. Therefore, the time until the dew condensation water adsorption can be confirmed is the same as that of the base material on which the protrusions shown in Comparative Example 1 are not formed. Regarding the frost formation, since the amount of surface irregularities is larger than that of Comparative Example 1, the time until frost formation can be confirmed is shortened.

  As a result, the portion excluding the tip of the protrusion 3 and the base 2 are preferably subjected to water repellent treatment.

<Summary of base material 1>
As described above, the base material 1 of the present invention has a water repellent treatment on the surface of the base material 1, a trapezoidal cross section, and a plurality of quadrangular pyramid projections, and the distance between the projections is 5 nm to It is 10 nm, and only the tip of the protrusion 3 is hydrophilically treated. By the said structure, the outstanding anti-fogging property and defrosting property can be acquired.

  The base material 1 of the present invention can remove frost and condensed water without using a heating device.

<Application example>
The apparatus of the application example of the base material 1 of this Embodiment is shown to Fig.5 (a) and FIG.5 (b).

  Fig.5 (a) is the example which applied the base material 1 of embodiment to the evaporator 18 (heat exchanger) of a refrigerator. The evaporator 18 includes the base material 1 and a cooling pipe 19. A cooling pipe 19 is provided through the plurality of base materials 1. The liquefied coolant flows through the cooling pipe 19. The evaporator 18 vaporizes and expands the coolant to absorb heat.

  By using the base material 1, the evaporator 18 is less likely to form frost. As a result, a decrease in cooling performance can be suppressed.

  FIG. 5B is an example in which the substrate 1 of the embodiment is applied to an outdoor camera 20. The outdoor camera 20 includes a base material 1 that is a cover, a camera control unit 21, and a camera body 26. The camera body 26 shoots under the control of the camera control unit 21.

  The camera body 26 shoots through the base material 1 of the cover. By using the base material 1, dew condensation or frost formation can be suppressed even in rainy weather or in a low temperature environment, and fogging can be prevented.

  In addition, it can be used for general heat exchanger equipment such as air conditioners and refrigerators. Can be widely used for cameras in general. Moreover, it can be used generally for glass such as window glass and automobile glass.

  The base material of the present invention can be used as a condensed water / frosting prevention material. Moreover, the base material of this invention can be used with the apparatus which has heat exchangers, such as a refrigerator, an air conditioner, and a refrigerator. It can also be used with devices that have water drops, such as cameras, glasses, and windows.

DESCRIPTION OF SYMBOLS 1 Base material 2 Base part 3 Protrusion part 4 Hydrophilic part 5 Water vapor 6 Condensed droplet 7 Base material 8 Base part 10 Peltier element 11 Aluminum plate 12 Resin plate 13 Heat sink 14 Fan 15 Thermocouple 16 Thermocouple 18 Evaporator 19 Cooling pipe 20 Camera 21 Camera control unit 22 Base material 23 Base 24 Projection 25 Hydrophobic coating 26 Camera body

Claims (7)

A plurality of quadrangular pyramidal protrusions located on at least one surface of the base,
A distance between tip portions of the plurality of protrusions is 5 nm or more and less than 10 nm ,
The tip of the protrusion is hydrophilically treated,
The tip is a base material that is an area of 10% to 25% of the length of the protrusion from the upper surface of the protrusion and the upper surface. The length of the protrusion is 0.1 μm or more and less than 10 μm,
The base material according to claim 1, wherein an angle of a side surface of the protruding portion is less than 90 ° with respect to a vertical direction. The base material according to claim 1, wherein water is repellent except for the tip of the protrusion. The base material according to claim 3, wherein the water repellent treatment is constituted by a molecular film made of alkylsilane containing no fluorine bond. The base material according to any one of claims 1 to 4 , wherein the plurality of protrusions are formed by aluminum fine hole machining by an anodic oxidation method. Wherein the plurality of projections, the base material according to any one of claims 1 to 5 formed by pattern printing of an etching process or a metal paste. The apparatus which has the said base material of any one of Claims 1-6 .

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