JP2014240728A - Dew condensation suppression member for refrigerator/freezer, and refrigerator/freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dew condensation suppression member for a refrigerator/freezer which has an excellent dew condensation suppressing effect and excellent quick-drying properties, and a refrigerator/freezer which comprises the dew condensation suppression member for the refrigerator/freezer and which suppresses dew condensation.SOLUTION: A dew condensation suppression member for a refrigerator/freezer is characterized as follows: at least one surface of a base material has a minute protrusion structure body comprising a minute protrusion group in which a plurality of minute protrusions made of a hardened material of a resin composition are arranged in an intimate contact state; and a distance between the adjacent minute protrusions is in the range of 50-500 nm on average.

Description

  The present invention relates to a dew condensation suppressing member used in a refrigeration and / or freezer, and a refrigeration and / or freezer provided with the dew condensation suppressing member.

Refrigerated showcases placed in stores, refrigerated freezers for home use or business use, etc., when the cooled internal space is exposed to the outside air when opening and closing, condensation tends to occur, preventing deterioration of stored items such as food, Prevention of condensation is required from the viewpoint of visibility.
Conventionally, in order to prevent dew condensation inside the refrigerated freezer, various methods have been tried, such as using a heat insulating member to block cold heat or using a heater for preventing dew condensation.
Also, on the glass part that is in front of the refrigerated showcase, a heat-insulating layer or gas layer is formed between the double glasses, or a heating wire is passed through the glass surface, etc. Has been. All of these methods are difficult to retrofit to ready-made products.

In addition, as a means for preventing condensation, it has also been proposed to use an antifogging member having water absorption performance on the substrate surface.
For example, Patent Document 1 discloses an antifogging article having a base and a water-absorbing crosslinked resin layer having a saturated water absorption of 45 mg / cm ³ or more provided on the surface of the base. Further, Patent Document 2 contains inorganic oxide particles, a polymer having a reactive functional group, and a crosslinking agent that reacts with the reactive functional group on the transparent resin film, and has a specific water absorption amount. An antifogging film having a fine void layer is disclosed.
However, the antifogging member having such a water absorption performance cannot exhibit the water absorption performance when the absorbed water reaches the saturated water absorption amount. Therefore, it is necessary to release the absorbed moisture in order to demonstrate the water absorption performance again, but it may take a long time to release the absorbed moisture, or the water absorption performance will be complete even if moisture is released. May not recover. Moreover, the anti-fogging member which has a water absorption performance will fall in water absorption by deterioration of material itself. For these reasons, the anti-fogging member having water absorption performance has a problem that it is difficult to exert the dew condensation suppressing effect for a long period of time. Further, the antifogging member having water absorption performance also has a problem that discoloration occurs due to deterioration of the material.

On the other hand, in Patent Document 3, as a refrigerated showcase having a high anti-fogging performance by maintaining hydrophilicity for a long time, at least the outer surface of the transparent material to be configured has fine particles of tungsten oxide or a composite material of tungsten oxide. A refrigerated showcase in which the average particle diameter of the fine particles is in the range of 1 nm to 200 nm and the aspect ratio of the fine particles is in the range of 1 to 3.5 is proposed.
However, since tungsten oxide is a visible light responsive photocatalytic material, it is difficult to exert a dew condensation suppressing effect in a dark room such as the inside of a refrigerator.

International Publication No. 2007/052710 Pamphlet JP 2012-86506 A JP 2010-96359 A

  The present invention has been made in view of the above problems, and includes a dew condensation suppressing member for a refrigerated freezer having an excellent dew condensation suppressing effect and an excellent quick drying property, and the dew condensation suppressing member for the refrigerated freezer is suppressed. The purpose is to provide a refrigerated freezer.

  The dew condensation suppressing member for a refrigerated freezer according to the present invention has a microprojection structure provided with a microprojection group in which a plurality of microprojections made of a cured resin composition are placed in close contact with at least one surface of a substrate. The average distance between adjacent microprotrusions is 50 to 500 nm.

  In the dew condensation suppressing member for a refrigerated freezer according to the present invention, the static contact angle of pure water on the surface of the microprojection structure is 20 ° or less by the θ / 2 method because the dew condensation suppressing effect is further improved. Is preferred.

  The dew condensation suppressing member for a refrigerated freezer according to the present invention has a static contact angle of n-hexadecane on the surface of the microprojection structure of 20 ° or less by the θ / 2 method from the viewpoint of excellent antifogging properties. preferable.

  The refrigeration freezer which concerns on this invention is equipped with the dew condensation suppression member for refrigeration freezers which concerns on the said this invention, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the dew condensation suppression member for refrigeration freezers which has the outstanding dew condensation suppression effect and the outstanding quick-drying property, and the said refrigeration freezer dew condensation suppression member can be provided, and the refrigeration freezer by which the dew condensation was suppressed can be provided.

It is sectional drawing which shows typically an example of the dew condensation suppression member for refrigerated refrigerators which concerns on this invention. It is sectional drawing (FIG.2 (a)), a perspective view (FIG.2 (b)), and top view (FIG.2 (c)) with which it uses for description of the multimodal microprotrusion which has two or more vertices. It is a figure which shows an example of a Delaunay diagram typically. It is a figure where it uses for description of a convex-shaped protrusion group. It is the schematic which shows an example of the manufacturing method of the dew condensation suppression member for refrigerators which concerns on this invention.

I. Next, embodiments of the dew condensation suppressing member for a refrigerated freezer according to the present invention will be described in detail, but the present invention is not limited to the following embodiments, and the scope of the purpose The present invention can be implemented with various modifications.
The dew condensation suppressing member for a refrigerated freezer according to the present invention has a microprojection structure provided with a microprojection group in which a plurality of microprojections made of a cured resin composition are placed in close contact with at least one surface of a substrate. The average distance between adjacent microprotrusions is 50 to 500 nm.
In addition, the refrigeration freezer in this invention should just have at least 1 function of refrigeration and a freezer, and includes all of the refrigerator, freezer, and the refrigeration freezer which has both the functions of refrigeration and freezing.

The dew condensation suppressing member for a refrigerated freezer according to the present invention includes a microprojection group in which microprojections are formed on a substrate and the microprojections are closely arranged with the above-mentioned distance between adjacent projections. Because of its structure, the liquid is easily spread and wet, and the spread liquid is difficult to re-aggregate and is held by the member. The reason why the spread liquid is difficult to be re-aggregated is that the liquid is held in the valleys between the microprojections constituting the microprojection structure, thereby suppressing the liquid from collecting and forming droplets according to gravity. This is also considered to be a factor. Moreover, since the microprojection structure has a large surface area, the microprojection structure surface is excellent in quick drying. As described above, the dew condensation suppressing member for a refrigerated freezer of the present invention is excellent in dew condensation suppressing effect and excellent in quick-drying properties. Therefore, it is possible to suppress the growth of bacteria such as molds due to moisture without the addition of an antibacterial agent.
In addition, the dew condensation suppressing member for a refrigerated freezer according to the present invention has sufficient water wetting and spreading due to the specific shape of the microprojection structure, and therefore excellent dew condensation suppression without using a water absorbing material or a photocatalytic material. Has an effect. Accordingly, the present invention has a wide range of material selection and does not require light energy.
Further, the dew condensation suppressing member for a refrigerated freezer according to the present invention has flexibility by using a flexible resin base material as a base material, so that the installation location is not easily limited and the installation work is easy. is there.

  FIG. 1 is a cross-sectional view schematically showing an example of a dew condensation suppressing member for a refrigerated freezer according to the present invention. The dew condensation suppressing member 100 for a refrigerated freezer shown in FIG. 1 has a microprojection structure 20 having a microprojection group in which a plurality of microprojections 2 are arranged in close contact with one surface of a substrate 10. The microprojection structure 20 is formed on a microprojection layer 21 made of a material different from the base material 10.

<Base material>
The base material used for this invention can be suitably selected according to a use, and is not specifically limited. Examples of the material used for the base material include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins, polyurethane resins, polyethersulfone and polycarbonate, Resins such as polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, cycloolefin copolymer, glass such as soda glass, potassium glass, lead glass, ceramics such as lead lanthanum zirconate titanate (PLZT) Inorganic materials such as quartz and fluorite, metals, paper, wood, and composite materials thereof.
The substrate may be a sheet or a film. Also, the substrate may be supplied in the form of a roll, may not be bent so that it can be wound, but may be bent by applying a load, or may be completely bent. Any of those that do not exist. Although the thickness of a base material can be suitably selected according to a use and is not specifically limited, Usually, it is 20-5000 micrometers.

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

The transmittance in the visible light region of the substrate used in the present invention can be appropriately adjusted depending on the application, and is not particularly limited. A transparent substrate of 80% or more can be used, or less than 80%. A semi-transparent substrate or an opaque substrate can also be used. The transmittance can be measured by JIS K7361-1 (Plastic—Testing method for total light transmittance of transparent material).
For example, when used for a transparent member such as a front plate of a refrigerated showcase, it is preferable to use a transparent substrate.
Moreover, when installing the dew condensation suppression member for refrigerator refrigerators of this invention to a glass part, polyester-type resin base materials, such as a polyethylene terephthalate (PET), are preferable from the point which provides the scattering resistance at the time of glass breakage.

<Microprojection structure>
The dew condensation suppressing member for a refrigerated freezer according to the present invention includes a microprojection structure including a microprojection group in which a plurality of microprojections made of a cured resin composition are placed in close contact with at least one surface of a substrate. Have
As shown in FIG. 1, the microprojection structure may be formed on a microprojection layer 21 made of a material different from the base material 10, and although not shown, it is integrated with the surface of the base material. It may be formed.

  Each microprotrusion constituting the microprotrusion structure is formed so as to be planted on a base material, and the shape thereof is not particularly limited, but when cut by a horizontal plane orthogonal to the depth direction of the microprotrusion Assuming that the cross-sectional area occupancy of the material part forming the microprotrusion in the horizontal cross section when assumed is gradually increased gradually from the top of the microprotrusion toward the deepest portion, that is, each microprotrusion is tapered. What has the structure which becomes is preferable. Specific examples of the shape of such minute protrusions include those having a vertical cross-sectional shape such as semicircular, semielliptical, triangular, parabolic, bell-shaped. The plurality of microprotrusions may have the same shape or different shapes.

Further, the microprojection group constituting the microprojection structure may include microprojections having a plurality of vertices (hereinafter sometimes referred to as “multimodal microprojections”). Note that a microprojection having only one vertex may be referred to as a “unimodal microprojection” in comparison with a multimodal microprojection. In addition, each convex portion that forms each vertex related to a multi-peak microprojection or a single-peak microprojection is appropriately referred to as a “peak”.
In the present invention, since the surface area of the microprojection structure is further increased by including multimodal microprojections in the microprojection group, the quick drying property and the dew condensation suppression effect are further improved. In addition, the multi-peaked microprojections are relatively thicker at the hem than the single-peaked microprojections, and the external force is distributed at more vertices. Therefore, it is considered that the external force applied to each apex can be reduced and the micro-projections made of the resin composition can be hardly damaged. Therefore, the dew condensation suppressing member for a refrigerated freezer of the present invention has multi-peaked microprojections, thereby improving the mechanical strength and scratch resistance.

FIG. 2 is a cross-sectional view (FIG. 2 (a)), a perspective view (FIG. 2 (b)), and a plan view (FIG. 2 (c)) for explaining the multi-peak microprojections. Note that FIG. 2 is a diagram schematically showing for easy understanding, and FIG. 2A is a diagram showing a cross section by a broken line connecting the vertices of continuous minute protrusions. In FIG. 2, the xy direction is the in-plane direction of the substrate 10, and the z direction is the height direction of the microprotrusions. In the dew condensation suppressing member 100 for a refrigerated freezer shown in FIG. 2A, the unimodal microprotrusions 2 are, for example, gradually increased in cross-sectional area (surface orthogonal to the height direction ( In FIG. 2, the cross-sectional area when cut along a plane parallel to the XY plane) is reduced, and one vertex is produced. On the other hand, as the multi-peak microprotrusions, for example, a groove g is formed at the tip portion as if a plurality of microprotrusions are combined, and the apex is two (2A), and there are three apexes. (2B), and those having four or more vertices (not shown). The shape of the unimodal microprotrusions 2 can be approximated by a round shape at the top like a paraboloid of revolution or a shape with a sharp apex like a cone. On the other hand, the shape of the multimodal microprotrusions 2A and 2B can be approximated by a shape in which a groove-shaped recess is cut in the vicinity of the top of the monomodal microprotrusion 2 and the top is divided into a plurality of peaks. it can. The shape of the multi-peak microprotrusions 2A and 2B has a plurality of maximal points when the vertical cross-sectional shape is cut by a virtual cut surface including a plurality of peaks and including the height direction (Z-axis direction in FIG. 2). The shape is approximated by an algebraic curve Z = a ₂ X ² + a ₄ X ⁴ +... + A _2n X ²ⁿ +.

  The ratio of the number of multimodal microprotrusions in all the microprotrusions present on the surface of the microprotrusion structure is not particularly limited, but is preferably 10% or more from the standpoint of exerting the above effects, Preferably it is 30% or more, more preferably 50% or more.

In the present invention, the microprotrusions constituting the microprotrusion structure have a distance d between the adjacent microprotrusions (hereinafter, referred to as “dwelling”) from the viewpoint of holding the member so that the liquid easily wets and spreads and the spread liquid does not re-aggregate. It is closely arranged so that the average d _AVG of “distance between adjacent projections d”) is 50 to 500 nm. The adjacent minute protrusions related to the distance d between the adjacent protrusions are so-called adjacent minute protrusions, and are protrusions that are in contact with the skirt portions of the minute protrusions that are base portions on the base material side. In the dew condensation suppressing member for a refrigerated freezer according to the present invention, the minute protrusions are closely arranged so that when the line segments are created so as to sequentially follow the valley portions between the minute protrusions, A mesh-like pattern formed by connecting a number of surrounding polygonal regions is produced. The adjacent minute protrusions related to the distance d between the adjacent protrusions are protrusions that share a part of the line segments constituting the mesh pattern.
Further, the average distance d _AVG between the adjacent adjacent protrusions of the minute protrusions is preferably 70 to 400 nm, more preferably 70 to 300 nm, and particularly preferably 70 to 180 nm from the viewpoint of improving wettability. preferable.

In addition, the average value _HAVG of the height H of the microprojections constituting the microprojection structure is not particularly limited, but from the viewpoint of holding the member so that the liquid easily wets and spreads and does not re-aggregate. It is preferable that it is 50-350 nm, and it is especially preferable that it is 100-250 nm.
Here, the height of each microprotrusion means the height of the peak (the highest peak) having the highest height at the top. In the case of a single-peaked microprojection such as the microprojection 2 in FIG. 2A, the height of the only peak at the top is the projection height of the microprojection. In the case of a multi-peak microprojection such as the microprotrusions 2A and 2B in FIG. 2A, the height of the microprotrusions has the highest peak height among a plurality of peaks sharing the ridge at the top. The height.

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

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

  (3) Next, a Delaunay diagram with the detected maximum point as a generating point is created. Here, Delaunay diagram is obtained by dividing the Voronoi region adjacent to the Voronoi region when the Voronoi division is performed with each local maximum as the generating point, and connecting the adjacent generating points with line segments. This is a net-like figure made up of triangular aggregates. Each triangle is called a Delaunay triangle, and a side of each triangle (a line segment connecting adjacent generating points) is called a Delaunay line. FIG. 3 is a diagram in which a Delaunay diagram (a diagram represented by a white line segment) is superimposed on a schematic diagram of an enlarged photograph in plan view.

  (4) Next, the frequency distribution of the line segment length of each Delaunay line, that is, the frequency distribution of the distance between adjacent maximum points (distance between adjacent protrusions) is obtained. In addition, when there is a groove-like recess at the top of the protrusion, or when the top is split into a plurality of peaks, from the obtained frequency distribution, the microstructure in which there is a recess at the top of such protrusion, The data resulting from the fine structure in which the top part is divided into a plurality of peaks is removed, and only the data of the projection body itself is selected to create a frequency distribution.

  Specifically, a fine structure in which a concave portion exists on the top of the protrusion, or a fine structure related to a fine protrusion (multi-modal micro protrusion) in which the top is divided into a plurality of peaks has such a fine structure. The distance between adjacent protrusions is clearly different from the numerical range in the case of non-protruding microprotrusions (single-peak microprotrusions). Thus, by removing the corresponding data using this feature, only the data of the projection body itself is selected and the frequency distribution is detected. More specifically, for example, about 5 to 20 adjacent single-peaked microprojections are selected from an enlarged photograph of the microprojections (group) in plan view, and the value of the distance between the adjacent projections is sampled. The frequency distribution is excluded by excluding values that are clearly out of the numerical range obtained by sampling (usually, data having a value of 1/2 or less of the average distance between adjacent protrusions obtained by sampling). To detect.

The same method is applied to obtain the average value _HAVG of the height H of the microprojections. First, the relative height difference of each local maximum point position from a specific reference position is acquired from the local maximum point obtained by the above (2) to form a histogram. The average value _HAVG of the protrusion height and the standard deviation σ are obtained from the frequency distribution based on the histogram. In the histogram of the protrusion height H, in the case of a multi-peak microprotrusion, the plurality of data are mixed for one protrusion due to having a plurality of vertices. In this case, the frequency distribution is obtained by adopting the vertex having the highest height from among the plurality of vertices belonging to the same microprotrusion at the heel (base) portion as the protrusion height of the microprotrusion.

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

  In the frequency distribution of the embodiment including multi-peak microprojections having a plurality of vertices as shown in FIG. 2, the distance d between adjacent projections (value on the horizontal axis) is, for example, a maximum value of a short distance of 20 nm and 40 nm. There are two types of local maxima, long maxima of 120 nm and 174 nm. Among these maximum values, the maximum value of the long distance corresponds to the arrangement of the microprojection bodies (the part from the middle to the heel below the top part), while the maximum value of the short distance exists in the vicinity of the top part. Corresponds to the apex (peak) of. As a result, the presence of multi-peaked microprotrusions can be seen also from the frequency distribution of the distance between the maximal points.

In addition, each microprotrusion constituting the microprotrusion structure may have a height difference. When there is a height difference in the height of each microprojection, for example, when various members are arranged on the surface of the microprojection structure of the dew condensation suppressing member for a refrigerated freezer, Only the high microprotrusions come into contact with the member. As a result, even when the shape of the fine protrusion having a high height is lost due to contact with an object, for example, the shape of the fine protrusion having a low height is maintained, so that the scratch resistance is improved. Furthermore, since only the high microprojections out of the many microprojections come into contact with the member, the relatively small microprojections are less likely to be contaminated, so that the contamination resistance is also improved. improves.
In addition, when the heights of the microprotrusions are variously different, the sliding can be remarkably improved as compared with the case where the microprotrusion structure is composed of only the microprotrusions having the same height. The handling of the dew condensation suppressing member for a refrigerated refrigerator can be facilitated.

  The height difference of each microprotrusion is preferably 15 nm or more and 60 nm or less when defined by the standard deviation. By being 15 nm or more, the slip, scratch resistance and contamination resistance of the surface of the microprojection structure are further improved. When the thickness exceeds 60 nm, a rough feeling on the surface of the microprojection structure may be felt.

In addition, at least a part of the microprojection group constituting the microprojection structure is formed adjacent to the top microprojection and the periphery of the top microprojection, and the height is lower than the top microprojection. You may comprise the group of a group of microprotrusions (it calls a "convex-shaped protrusion group" in this invention) which consists of a some peripheral microprotrusion. Thereby, the contamination resistance and the scratch resistance on the surface of the microprojection structure can be further improved, and slipping can be further improved.
FIG. 4 shows a perspective view (FIG. 4A) and a plan view (FIG. 4B) of a convex protrusion group constituted by a plurality of minute protrusions. The convex projection group 22 shown in FIG. 4 includes a top microprojection 2C having a relatively high height and a plurality of peripheral microprojections 2D having a relatively low height arranged adjacent to the periphery thereof. 4 (a) and 4 (b) are diagrams schematically shown for ease of understanding, where the xy direction is the in-plane direction of the substrate, and the z direction is the height of the minute protrusion. It is the direction.
In the present invention, the top microprotrusion has a relatively higher height than the peripheral microprotrusions, and the height difference is 15 nm or more, and the height difference is 20 nm or more. Is preferred. In addition, the difference in height is preferably 60 nm or less from the viewpoint of suppressing the feeling of roughness on the surface of the microprojection structure.

  In the microprojection structure, although not particularly limited, as the stain resistance and scratch resistance are further improved, as the microprojections arranged around the convex projection group are separated from the top microprojections, It is preferable that they are arranged so that the height decreases sequentially.

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

The aspect ratio of the fine protrusions (average projection height _{H AVG} / average adjacent protrusions distance _{d AVG)} is not particularly limited, but is preferably 0.4 to 2.5, with 0.8 to 2.1 It is particularly preferred.

  In the dew condensation suppressing member for a refrigerated freezer of the present invention, the static contact angle of pure water on the surface of the microprojection structure is preferably 20 ° or less by the θ / 2 method, and particularly preferably 10 ° or less. preferable. Thereby, since the water adhering to the surface of the microprojection structure becomes easy to spread and spread, it is excellent in quick-drying and the effect of suppressing condensation is improved. The static contact angle of pure water on the surface of the microprojection structure is not particularly limited, but is usually 3 ° or more.

  The surface of the microprojection structure has a static contact angle of n-hexadecane of preferably 20 ° or less, particularly preferably 16 ° or less, according to the θ / 2 method. Thereby, since the oily dirt adhering to the surface of the microprojection structure becomes thin and spreads easily, the dirt is hardly noticeable and the antifogging property is improved. The static contact angle of n-hexadecane on the surface of the microprojection structure is not particularly limited, but is usually 8 ° or more.

In the present invention, the static contact angle is determined by dropping a 1.0 μL droplet of a solvent (pure water or n-hexadecane) whose contact angle is to be measured on the surface of the object to be measured. The contact angle measured according to the θ / 2 method for calculating the contact angle from the angle of the straight line connecting the left and right end points and the vertex of the dropped droplet to the solid surface. As the measuring device, for example, a contact angle meter DM 500 manufactured by Kyowa Interface Science Co., Ltd. can be used.
The static contact angle can be adjusted by changing the components of the resin composition forming the microprojection structure, the shape of the microprojection structure, and the like.

In the present invention, when the microprojection structure is formed on a microprojection layer which is a separate layer made of a material different from the base material, the thickness of the microprojection layer is not particularly limited, but is usually 3 to 30 μm. is there. Note that the thickness of the microprojection layer in this case means the distance in the direction perpendicular to the substrate plane from the interface on the substrate side of the microprojection layer to the height of the top of the microprojection having the highest height (FIG. T in 1).
In the present invention, the microprojection structure may be formed on both surfaces of the substrate.

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

The resin composition used in the present invention may contain fine particles such as organic fine particles or inorganic fine particles as necessary for the purpose of imparting strength, but the metal-containing fine particles having a particle size of 100 nm or more. The content is preferably less than 20% by mass relative to the total solid content, more preferably less than 10% by mass, and even more preferably less than 5% by mass. Thereby, the transparency of the dew condensation suppressing member for a refrigerated freezer is improved, and the cost is reduced. As the content of the metal-containing fine particles having a particle size of 100 nm or more in the resin composition is higher, the dew condensation suppressing member for a refrigerated freezer of the present invention may have increased haze and lower transparency.
Further, the microprojection structure is preferably formed by shaping as will be described later. However, the higher the content of the metal-containing fine particles having a particle diameter of 100 nm or more in the resin composition, the more easily a problem due to shaping is caused.
In view of the fact that the metal-containing fine particles are likely to aggregate, the content of the metal-containing fine particles having a particle diameter of 4 nm or more is more preferably less than 20% by mass, more preferably 10%. It is preferably less than 5% by weight, more preferably less than 5% by weight, and it is preferable not to contain metal-containing fine particles.

  Examples of the metal-containing fine particles include metal elements such as titanium, aluminum, cerium, zirconium, neodymium, tungsten, vanadium, lead, zinc, nickel, bismuth, tin, and scandium, silicon, boron, germanium, arsenic, tellurium, and the like. Metals such as semi-metal elements, alkali metals such as lithium, sodium, potassium, rubidium, cesium and francium, alkaline earth metals such as magnesium, calcium, strontium, barium and radium, or fine particles of oxides of these metals Can be mentioned.

  The resin composition used in the present invention may further comprise a polymerization initiator, a release agent, a photosensitizer, an antioxidant, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, and a viscosity adjustment as necessary. An agent, an adhesion improver, etc. can also be contained.

Further, the resin composition used in the present invention is not particularly limited, but from the viewpoint of improving the dew condensation suppressing effect on the surface of the microprojection structure, the static contact angle of pure water on the surface when a flat cured film is formed. However, it is preferable that it is 85 degrees or less by the (theta) / 2 method, More preferably, it is 70 degrees or less, More preferably, it is 60 degrees or less.
Further, the resin composition used in the present invention is not particularly limited, but from the viewpoint of improving the dew condensation suppressing effect on the surface of the microprojection structure, static contact of n-hexadecane on the surface when a flat cured film is formed. The angle is preferably 70 ° or less, more preferably 60 ° or less in the θ / 2 method.

  The dew condensation suppressing member for a refrigerator / freezer according to the present invention is stored, transported, bought and sold, post-processed or constructed in a state in which a peelable protective film is temporarily bonded to the surface of the microprojection structure, and the protective film is peeled off at appropriate times. It can also be set as the form removed. Thereby, damage and contamination of the surface of the microprojection structure during storage, transportation, etc. can be prevented.

  Further, the dew condensation suppressing member for a refrigerated freezer of the present invention is formed by forming an adhesive layer on a surface not having a microprojection structure, and further laminating a release film on the surface of the adhesive layer in a peelable manner. It can also be a product. As the adhesive, various types of known adhesive forms such as a pressure-sensitive adhesive (pressure-sensitive adhesive), a two-component curable adhesive, an ultraviolet curable adhesive, a thermosetting adhesive, and a hot-melt adhesive can be used. .

  The transmittance in the visible light region of the dew condensation suppressing member for a refrigerated freezer of the present invention can be appropriately adjusted depending on the application, and is not particularly limited, and may be 80% or more transparent or less than 80%. It may be translucent or opaque. The transmittance can be measured by JIS K7361-1 (Plastic—Testing method for total light transmittance of transparent material).

<Method for producing dew condensation suppressing member for refrigerated refrigerator>
Although the manufacturing method of the dew condensation suppression member for refrigerated freezers of this invention will not be specifically limited if it is a method which can manufacture the dew condensation suppression member for refrigerated freezers of this invention mentioned above, it is excellent in a moldability and can perform stable mass production. In view of this, a method of forming a microprojection structure on at least one surface of the substrate by shaping is preferable.
The microprojection structure may be shaped on the surface of another layer made of a material different from the base material provided on the base material, or the base material is made of a shapeable material such as a resin composition. When it becomes, you may shape directly on the said base-material surface.

As a manufacturing method of the dew condensation suppression member for refrigerated freezers of this invention, the following methods etc. are mentioned, for example. That is, first, a resin composition for forming a microprojection layer is applied onto a substrate to form a coating film, and the uneven shape of the original plate for forming a microprojection structure having a desired uneven shape is obtained by using the resin composition. For example, a method for forming a microprojection structure by curing the resin composition after shaping the coating film, and peeling the original plate for forming the microprojection structure.
The concave / convex shape of the original plate for forming a microprojection structure is a shape in which a large number of micropores are densely formed and corresponds to the shape of a group of microprojections provided in the microprojection structure.
Moreover, the method of shaping the concave / convex shape of the original plate for forming a microprojection structure into a resin composition and curing the resin composition can be appropriately selected according to the type of the resin composition.

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

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

  FIG. 5 shows the production of a dew condensation suppressing member for a refrigerated freezer according to the present invention, using an ultraviolet curable resin composition as a resin composition for forming a microprojection structure and using a roll mold as an original plate for forming the microprojection structure. An example of how to do this is shown. In this manufacturing method, first, in the resin supply step, an uncured and liquid ultraviolet curing that forms the receiving layer 21 ′ of the microprojection structure to be the microprojection layer 21 on the base material 10 in the form of a strip by the die 31. The conductive resin composition is applied. In addition, about application | coating of an ultraviolet curable resin composition, not only the case by the die | dye 31 but various methods are applicable. Subsequently, the pressing roller 33 presses and presses the substrate 10 against the peripheral side surface of the roll die 32 which is a shaping die, thereby bringing the uncured receiving layer 21 ′ into close contact with the substrate 10, The minute concavo-convex recesses formed on the peripheral side surface of the roll mold 32 are sufficiently filled with the ultraviolet curable resin composition constituting the receiving layer 21 ′. In this state, the ultraviolet curable resin composition is cured by irradiation with ultraviolet rays, whereby the microprojection layer 21 having the microprojection structure is formed on the surface of the substrate 10. Subsequently, the base material 10 is peeled from the roll mold 32 through the peeling roller 34 together with the hard microprojection layer 21. If necessary, an adhesive layer or the like is laminated on the base material 10 and then cut into a desired size. Thereby, the dew condensation suppressing member for a refrigerated freezer according to the present invention in which a microprojection structure having a desired shape is formed is efficiently mass-produced.

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

  In the above-described embodiment, the case where the microprojection structure is formed on the film-shaped base material by the shaping process using the roll mold is described. However, the present invention is not limited thereto, and the shape of the base material is not limited thereto. Depending on the process, the process and mold for the shaping process can be changed as appropriate. For example, a microprojection structure can be formed on a sheet-like substrate by a shaping process using a shaping mold having a flat plate shape or a specific curved surface.

<Uses of dew condensation suppression members for refrigerated refrigerators>
The dew condensation suppressing member for a refrigerated freezer of the present invention can be used as a member that constitutes a portion of the refrigerated freezer where condensation is likely to occur. Examples of the refrigerated freezer include a refrigerated freezer showcase, a domestic or commercial refrigerated freezer, a refrigerated freezer, a refrigerated freezer container, and the like. As described above, “refrigerated” in the present invention includes those having at least one function of refrigeration and freezing. For example, a refrigerated freezer showcase includes a refrigerated showcase, a freezer. It includes both a showcase and a refrigerated freezer showcase having both refrigeration and freezing functions.
The dew condensation suppressing member for a refrigerated freezer of the present invention is preferably used, in particular, in an aspect that is later attached to an interior member that constitutes an internal space to be cooled of a ready-made refrigerated freezer, or as an interior member of a refrigerated freezer. Can do. In the cooled internal space of the refrigerated freezer, dew condensation is likely to occur due to outside air entering when opening and closing or the like, so that the dew condensation suppressing effect of the member according to the present invention can be particularly effectively exhibited.
Examples of the interior member include an inner wall, a partition plate, an observation window, a sensor probe for measuring internal environment, a manual input unit and its peripheral member, and an internal illumination unit and its peripheral member.
Moreover, in particular, in the case of the dew condensation suppressing member for a refrigerated freezer of the present invention having a transmittance of 80% or more, even if the member is installed in the refrigerated freezer later, a dew condensation suppressing effect is imparted without hindering the design. It is preferable because it can be used.
Furthermore, the dew condensation suppressing member for a refrigerated freezer of the present invention is a material portion that forms the micro protrusion in a horizontal cross section when the micro protrusion is assumed to be cut by a horizontal plane perpendicular to the depth direction of the micro protrusion. The cross-sectional area occupancy rate has a structure that increases gradually and gradually as it approaches the deepest part from the top of the microprotrusions, and is transparent when the maximum value of the distance d between the adjacent microprotrusions is 380 nm or less. Even if it is a case where it uses for the internal side wall and partition member of a showcase, it is preferable from the point which suppresses condensation and improves visibility.

II. Refrigerated freezer The refrigerated freezer which concerns on this invention is equipped with the dew condensation suppression member for refrigerated refrigerators which concerns on the said this invention, It is characterized by the above-mentioned.
Since the dew condensation suppressing member for a refrigerated freezer has an excellent dew condensation suppressing effect and an excellent quick-drying property, in the refrigerated freezer according to the present invention, dew condensation is suppressed at a portion provided with the member.
As a refrigeration freezer which concerns on this invention, the refrigeration freezer illustrated as an application of the dew condensation suppression member for refrigeration freezers of the said this invention is mentioned, for example.
Such a refrigerated freezer is particularly susceptible to dew condensation due to outside air entering the cooled internal space during opening and closing, etc. Therefore, in the refrigerated freezer according to the present invention, the dew condensation suppressing member for the refrigerated freezer of the present invention is provided. Condensation can be particularly effectively suppressed by using the interior space as the interior member itself or by sticking it to the interior member.

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

(Production of mold 2)
A microprojection structure having an average distance between adjacent micropores of 150 nm and an average depth of 200 nm, in the same manner as in the manufacture of the mold 1, except that the same operation as that of the mold 1 was used and the repeated operation was added seven times. A forming mold 2 was obtained. Note that the fine uneven shape formed on the aluminum layer of the mold 2 has a part of micro holes that become micro projections having a plurality of apexes, and some micro holes have variations in depth. It was a shape.

(Production of mold 3)
Except that the first etching treatment time was 60 seconds, the second etching treatment time was 130 seconds, and the repeating operation was additionally performed seven times, the average distance between adjacent micro-holes was 200 nm, the average A mold 3 for forming a microprojection structure having a depth of 160 nm was obtained. Note that the fine uneven shape formed in the aluminum layer of the mold 3 has a part of micro holes that become micro projections having a plurality of vertices, and some micro holes have variations in depth. It was a shape.

(Production of mold 4)
Except that the first etching treatment time was 70 seconds, the second etching treatment time was 170 seconds, and the repeating operation was additionally performed five times, in the same manner as in the fabrication of the mold 1, the average distance between adjacent micropores was 400 nm, the average A mold 4 for forming a microprojection structure having a depth of 210 nm was obtained. In addition, the fine uneven shape formed in the aluminum layer of the mold 4 has a part of micro holes which become micro protrusions having a plurality of apexes, and some micro holes have variations in depth. It was a shape.

(Production of mold 5)
Except that the first etching treatment time was 70 seconds, the second etching treatment time was 170 seconds, and the repeating operation was additionally performed seven times, the average distance between adjacent micropores was 500 nm and the average was the same as in the manufacture of the mold 1. A mold 5 for forming a microprojection structure having a depth of 230 nm was obtained. In addition, the fine uneven shape formed in the aluminum layer of the mold 5 has a part of minute holes that become minute protrusions having a plurality of apexes, and some of the minute holes have variations in depth. It was a shape.

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

(Preparation of resin composition B)
The following components were mixed to prepare a resin composition B for forming a microprojection structure.
-EO-modified bisphenol A diacrylate 30 parts by mass-EO-modified trimethylolpropane triacrylate 20 parts by mass-dodecyl acrylate 50 parts by mass-diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide (lucillin TPO) 1 part by mass

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

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

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

[Example 2]
A dew condensation suppressing member for a refrigerated freezer of Example 2 was obtained in the same manner as in Example 1 except that the mold 2 was used as a mold for forming the microprojection structure.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 2 was observed by SEM, a microprojection group having an average distance between adjacent microprojections of 150 nm and an average microprojection height of 200 nm was formed. Moreover, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference of standard deviation 25 nm.

[Example 3]
A dew condensation suppressing member for a refrigerated freezer of Example 3 was obtained in the same manner as in Example 1 except that the mold 3 was used as a mold for forming the microprojection structure.
When the cross section of the surface of the dew condensation suppression member for a refrigerated freezer of Example 3 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 200 nm and an average microprojection height of 160 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.

[Example 4]
Example 4 is the same as Example 1 except that the resin composition B is used as the resin composition for forming the microprojection structure and the mold 2 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 4 was observed by SEM, a microprojection group having an average distance between adjacent microprojections of 150 nm and an average microprojection height of 200 nm was formed. Moreover, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference of standard deviation 25 nm.

[Example 5]
Example 5 is the same as Example 1 except that the resin composition C is used as the resin composition for forming the microprojection structure and the mold 2 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 5 was observed by SEM, a microprojection group having an average distance between adjacent microprojections of 150 nm and an average microprojection height of 200 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 35 nm.

[Example 6]
Example 6 is the same as Example 1 except that the resin composition A is used as the resin composition for forming the microprojection structure and the mold 4 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated refrigerator of Example 6 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 400 nm and an average microprojection height of 210 nm was formed. Moreover, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference of standard deviation 25 nm.

[Example 7]
Example 7 is the same as Example 1 except that the resin composition B is used as the resin composition for forming the microprojection structure and the mold 4 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 7 was observed with an SEM, a microprojection group having an average distance between adjacent microprojections of 400 nm and an average microprojection height of 210 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.

[Example 8]
Example 8 is the same as Example 1 except that the resin composition C is used as the resin composition for forming the microprojection structure and the mold 4 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 8 was observed by SEM, a microprojection group having an average distance between adjacent microprojections of 400 nm and an average microprojection height of 210 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.

[Example 9]
Example 9 is the same as Example 1 except that the resin composition A is used as the resin composition for forming the microprojection structure and the mold 5 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 9 was observed by SEM, a microprojection group having an average distance between adjacent microprojections of 500 nm and an average microprojection height of 230 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 35 nm.

[Example 10]
Example 10 is the same as Example 10 except that the resin composition B is used as the resin composition for forming the microprojection structure and the mold 5 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 10 was observed by SEM, a microprojection group having an average distance between adjacent microprojections of 500 nm and an average microprojection height of 230 nm was formed. Moreover, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference of standard deviation 25 nm.

[Example 11]
Example 11 is the same as Example 1 except that the resin composition C is used as the resin composition for forming the microprojection structure and the mold 5 is used as the mold for forming the microprojection structure. A dew condensation suppressing member for a refrigerated freezer was obtained.
When the cross section of the surface of the dew condensation suppressing member for a refrigerated freezer of Example 11 was observed by SEM, a microprojection group having an average distance between adjacent microprojections of 500 nm and an average microprojection height of 230 nm was formed. Further, a part of the microprotrusions are microprotrusions having a plurality of vertices, and the height of each microprotrusion has a height difference with a standard deviation of 30 nm.

[Comparative Example 1]
On the base material (material: PET, thickness: 25 μm, trade name: Lumirror, manufactured by Toray Industries, Inc.), the resin composition A is applied so as to form a flat film having a thickness of 20 μm after curing. The resin for refrigeration freezer of the comparative example 1 was obtained by irradiating an ultraviolet-ray with energy of 2000 mJ / cm < ² > and hardening resin.

[Comparative Example 2]
A member for a refrigerated freezer of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the resin composition B was used instead of the resin composition A.

[Comparative Example 3]
A refrigerated freezer member of Comparative Example 3 was obtained in the same manner as Comparative Example 1 except that the resin composition C was used instead of the resin composition A.

[Comparative Example 4]
In the refrigerated freezer member obtained in Comparative Example 1, the cured resin surface was roughened using # 2000 sandpaper to form irregularities on the surface, and the refrigerated freezer member of Comparative Example 4 was obtained. It was.

[Comparative Example 5]
In the refrigerated freezer member obtained in Comparative Example 1, the cured resin surface was roughened using # 1200 sandpaper to form irregularities on the surface, and the refrigerated freezer member of Comparative Example 5 was obtained. It was.

[Comparative Example 6]
First, the anti-glare film which has uneven | corrugated shape on the surface was produced by hardening the resin composition D in the film form of thickness 25 micrometers. Next, the antiglare film is bonded onto a base material (material: PET, thickness: 25 μm, trade name: Lumirror, manufactured by Toray Industries, Inc.) via an adhesive layer, whereby the refrigerated freezer member of Comparative Example 6 is obtained. Obtained.
When the cross-section of the surface of the refrigerated freezer member of Comparative Example 6 was observed by SEM, the surface on the antiglare film side had minute protrusions with variations in height within a range of 10 to 800 nm in height, between adjacent minute protrusions. Irregular uneven | corrugated shape arrange | positioned irregularly in the range of distance 500nm-1 micrometer was formed.

[Comparative Example 7]
A refrigerated freezer member of Comparative Example 7 was obtained in the same manner as in Example 1 except that the resin was cured by irradiating ultraviolet rays with an energy of 1500 mJ / cm ² .
When the cross section of the surface of the refrigerated freezer member of Comparative Example 7 was observed by SEM, the shape of the mold was not sufficiently shaped, the shape of each microprojection was not tapered, and each microprojection was closely It was not arranged. The average distance between adjacent microprotrusions was 650 nm, and the average microprotrusion height was 150 nm.

[Comparative Example 8]
A refrigerated freezer member of Comparative Example 8 was obtained in the same manner as in Example 4 except that the resin was cured by irradiating ultraviolet rays with an energy of 1500 mJ / cm ² .
When the cross section of the surface of the refrigerated freezer member of Comparative Example 8 was observed by SEM, the shape of the mold was not sufficiently shaped, the shape of each microprojection was not tapered, and each microprojection was closely It was not arranged. The average distance between adjacent minute protrusions was 600 nm, and the average minute protrusion height was 200 nm.

[Comparative Example 9]
A refrigerated freezer member of Comparative Example 9 was obtained in the same manner as in Example 5 except that the resin was cured by irradiating ultraviolet rays with an energy of 1500 mJ / cm ² .
When the cross section of the surface of the refrigerated freezer member of Comparative Example 9 was observed by SEM, the shape of the mold was not sufficiently shaped, the shape of each microprojection was not tapered, and each microprojection was closely It was not arranged. The average distance between adjacent minute protrusions was 600 nm, and the average minute protrusion height was 150 nm.

(Evaluation)
The following evaluation was performed about the dew condensation suppression member for refrigeration freezers obtained in Examples 1-11 and the member for refrigeration freezers obtained in Comparative Examples 1-9.

<Measurement of static contact angle>
The substrate side surface of the obtained refrigerated freezer dew condensation prevention member or refrigerated freezer member is attached to a black acrylic plate via an adhesive layer, and the dew condensation freezing member for refrigerated freezer on the side opposite to the black acrylic plate or refrigerated A drop of 1.0 μL of pure water (distilled water for liquid chromatography (manufactured by Junsei Chemical Co., Ltd.)) was dropped on the surface of the freezer member, and after contacted 1 second, contact angle meter DM manufactured by Kyowa Interface Science Co., Ltd. Using 500, the static contact angle was measured according to the θ / 2 method.
Moreover, the static contact angle was similarly measured using n-hexadecane instead of pure water.
The evaluation results are shown in Table 1.

<Quick drying evaluation>
The substrate side surface of the obtained refrigeration freezer dew condensation suppression member or the refrigeration freezer member is attached to a glass plate via an adhesive layer, and the surface of the dew condensation freezing member for the refrigeration freezer opposite to the side on which the glass plate is present. Or it arrange | positioned horizontally on the warm bath heated at 80 degreeC so that water vapor | steam might hit the member for refrigeration freezer, and water vapor | steam was applied for 3 minutes. Then, the dew condensation prevention member for refrigeration freezer or the member for refrigeration freezer was arrange | positioned horizontally so that a glass plate surface might become down, and it left still for 3 minutes in the environment of temperature 25 degreeC and humidity 50% RH.
Next, blue cobalt chloride paper (manufactured by Advantech Toyo Co., Ltd.) previously dried in an oven at 80 ° C. is applied to the surface of the condensation control member for a refrigerated freezer or a member for a refrigerated freezer that has been exposed to water vapor, and is visually presented. The color was observed and the quick drying property was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
Cobalt chloride paper turns blue when dried, and turns red when moisture adheres.
[Quick Drying Evaluation Criteria]
○: Cobalt chloride paper remained blue and was dry.
X: Cobalt chloride paper changed from blue to red, and adhesion of moisture was confirmed.

<Dew condensation suppression evaluation>
The base material side surface of the obtained refrigeration / freezer dew condensation suppression member or refrigeration / freezer member is pasted to the front door inner glass surface and inner wall of Hoshizaki Electric's refrigerated freezer showcase (RS-63XT) via an adhesive layer. I attached. Further, blue cobalt chloride paper (manufactured by Advantech Toyo Co., Ltd.) previously dried in an oven at 80 ° C. was pasted thereon. Further, as Comparative Examples 10 and 11, cobalt chloride paper similar to that described above was pasted on the front door and the inner wall on which nothing was pasted.
The refrigerated showcase was installed in an environment maintained at a temperature of 25 ° C. and a humidity of 60%, and the temperature inside the refrigerated showcase was set to a predetermined temperature shown in Table 2. The chamber was kept at a predetermined temperature for 20 minutes, then the door was opened, and the chamber was exposed to the outside air (temperature 25 ° C., humidity 60%). After the door was opened, the cloudiness of the front door after 1 minute and the color change of the cobalt chloride paper affixed to the front door and the inner wall were visually confirmed.
Next, the door of the refrigerated freezer display case was closed, and after 1 minute, the cloudy state of the front door and the color change of the cobalt chloride paper affixed to the front door and the inner wall were visually confirmed.
Based on the following criteria, the dew condensation suppression member for the refrigerated freezer or the refrigerated freezer member affixed to the front door and the inner wall of the refrigerated freezer showcase, and the dew condensation suppression evaluation of the front door and the inner wall in an unattached state were performed.
The evaluation results are shown in Table 2.
[Dew condensation suppression evaluation at the front door]
○: No cloudiness and cobalt chloride paper remains blue.
Δ: Slightly cloudy, cobalt chloride paper was blue to slightly purple.
X: There was clearly cloudiness, and the cobalt chloride paper changed from blue to red.
[Dew condensation suppression evaluation on the inner wall]
○: Cobalt chloride paper remains blue and does not change.
Δ: Cobalt chloride paper was slightly purple from blue.
X: Cobalt chloride paper changed from blue to red.

(Summary of results)
In the front door made of glass of the refrigerated freezer showcase (Comparative Example 10) and the resin inner wall of the refrigerated freezer showcase (Comparative Example 11), no dew condensation was observed by the above dew condensation suppression evaluation method. It was to be done.
On the other hand, in the dew condensation suppressing member for a refrigerated freezer obtained in Examples 1 to 11, the microprojection structure formed on the base material has a plurality of microprojections made of a cured product of the resin composition. Since the microprojections are arranged closely with a distance, the liquid easily spreads and is excellent in quick-drying and dew condensation suppression effects. Among these, Examples 1 to 8 in which the average distance between the microprotrusions was relatively small were particularly excellent in the dew condensation suppressing effect.
On the other hand, since the surface of the resin layer formed on the base material was unprocessed and flat, the members for refrigerated freezers obtained in Comparative Examples 1 to 3 were inferior in quick-drying and dew condensation suppression effects.
The members for refrigerated refrigerators obtained in Comparative Examples 4 to 9 were also inferior in quick-drying and dew condensation suppression effects. These are considered because the unevenness | corrugation shape of the resin layer surface formed on the base material was inadequate and hydrophilicity was not able to be improved. In Comparative Examples 7 to 9, since the ultraviolet irradiation was insufficient, the resin hardened in a state where the microprotrusions were in contact with each other. As a result, independent microprotrusions were not continuously formed, as if It is thought that hydrophilicity was lowered because it behaved as a large protrusion shape.

DESCRIPTION OF SYMBOLS 10 Base material 20 Microprotrusion structure 2 Microprotrusion 21 Microprotrusion layer 21 'Receptive layer 22 Convex protrusion group 31 Die 32 Roll die 33 Pressing roller 34 Peeling roller 100

The dew condensation suppressing member for a refrigerated freezer according to the present invention has a microprojection structure provided with a microprojection group in which a plurality of microprojections made of a cured resin composition are placed in close contact with at least one surface of a substrate. in a body, average 50~500nm der the distance between adjacent said microprojection is, the ratio of the number of microprojections having a plurality of vertices in the entire fine in protrusions constituting the microprojections group more than 10% characterized in that there.

Claims (4)

A microprojection structure including a microprojection group in which a plurality of microprojections made of a cured product of the resin composition are arranged in close contact with at least one surface of a substrate;
The dew condensation suppressing member for a refrigerated freezer, characterized in that the average distance between adjacent microprotrusions is 50 to 500 nm.   The dew condensation suppressing member for a refrigerator-freezer according to claim 1, wherein a static contact angle of pure water on the surface of the microprojection structure is 20 ° or less by a θ / 2 method.   The dew condensation suppressing member for a refrigerated freezer according to claim 1 or 2, wherein a static contact angle of n-hexadecane on the surface of the microprojection structure is 20 ° or less by a θ / 2 method.   A refrigerated freezer comprising the dew condensation suppressing member for a refrigerated freezer according to any one of claims 1 to 3.

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