JP2022094525A - Liquid-repellent structure and packaging material - Google Patents

Abstract

To provide a liquid repellent structure having excellent liquid repellency for a long period of time.SOLUTION: A liquid repellent structure includes: a surface onto which liquid repellency is to be imparted; and a liquid repellent layer formed on the surface. The liquid repellent layer includes: a binder resin containing a fluorine-containing resin; and a filler dispersed in the binder resin. A value Smr2/Smr1 obtained by dividing, with a load area ratio Smr1 separating a projection crest part and a core part of a liquid repellent layer surface, a load area ratio Smr2 separating a projection valley part and the core part of the liquid repellent layer surface obtained by a three-dimensional surface roughness analysis is 5 or less.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to liquid repellent structures and packaging materials.

Various aspects of the water repellent structure are known. For example, Patent Document 1 discloses a single-layer water-repellent heat-sealing film containing a thermoplastic resin and hydrophobic particles.

Japanese Unexamined Patent Publication No. 2017-155183

In the invention described in Patent Document 1, water repellency is evaluated by the contact angle with water droplets and the like. However, in the invention described in the same document, the liquid repellency to liquid substances containing oil (for example, salad oil, curry, fresh cream) has not been investigated. In particular, the liquid repellency is required to be maintained for a long period of time, but it is unclear whether this is possible in the invention described in the same document.

It is an object of the present disclosure to provide a liquid-repellent structure having excellent liquid-repellent properties over a long period of time. Another object of the present disclosure is to provide a packaging material having the above-mentioned liquid-repellent structure on the side in contact with the article.

The liquid-repellent structure according to the present disclosure is a liquid-repellent structure including a surface to be imparted with liquid-repellent properties (hereinafter, sometimes referred to as a "processed surface") and a liquid-repellent layer formed on the surface. In the body, the liquid-repellent layer contains a binder resin containing a fluorine-containing resin and a filler dispersed in the binder resin, and a protrusion valley on the surface of the liquid-repellent layer obtained by a three-dimensional surface roughness analysis. The value Smr2 / Smr1 obtained by dividing the load area ratio Smr2 that separates the portion and the core portion by the load area ratio Smr1 that separates the protruding mountain portion and the core portion on the surface of the liquid-repellent layer is 5 or less.

The liquid-repellent layer provided in the liquid-repellent structure has excellent liquid-repellent properties against water and oil, and can maintain the liquid-repellent properties for a long period of time. As will be described later, the value of Smr2 / Smr1 indicates the surface texture (state of unevenness) of the liquid-repellent layer on the surface of the liquid-repellent structure, and by setting this value to 5 or less, it becomes difficult for the liquid to enter the recess. The inventors speculate that not only the liquid repellency but also the liquid repellency durability is improved.

In the liquid-repellent structure, the fluorine atom concentration on the surface of the liquid-repellent layer obtained by X-ray photoelectron spectroscopy may be 35 to 50 atom%. This makes it easier to improve the liquid repellent durability.

In the liquid-repellent structure, the filler may include a first filler having a structure in which a plurality of primary particles are connected in a bead shape. The beaded structure of the beaded filler can easily impart flexibility to the liquid repellent layer due to its three-dimensional structure, and can maintain the liquid repellent property for a longer period of time.

In the liquid-repellent structure, the fluorine-containing resin may contain a fluorine-acrylic copolymer. By containing the fluorine-acrylic copolymer, the liquid repellency can be maintained for a longer period of time.

In the liquid repellent structure, the filler may contain a scaly second filler. By including the scaly filler in the liquid-repellent layer, unevenness is formed more efficiently on the surface thereof, and it becomes easy to maintain the liquid-repellent property for a longer period of time.

The liquid-repellent structure may further include an underlayer between the surface and the liquid-repellent layer, the underlayer containing a thermoplastic resin and a third filler having an average primary particle diameter of 5-60 μm. You can stay. This makes it possible to form coarse irregularities on the liquid-repellent structure. Since the coarse unevenness facilitates point contact between the liquid-repellent layer and the contents, deterioration of the liquid-repellent property can be further suppressed.

In the liquid-repellent structure, the surface roughness Sa may be 1.5 to 15.0 μm so that the effect of holding the contents by point contact can be easily obtained.

The present disclosure provides a packaging material having the above-mentioned liquid-repellent structure on the side in contact with the article. As described above, the liquid-repellent layer provided in the liquid-repellent structure has excellent liquid-repellent properties against water and oil, and can maintain the liquid-repellent properties for a long period of time. The liquid-repellent layer can be particularly preferably used for articles containing at least one of an oil component and an O / W type emulsion.

According to the present disclosure, it is possible to provide a liquid-repellent structure having excellent liquid-repellent properties for a long period of time. The liquid-repellent structure of the present disclosure can exhibit excellent liquid-repellent properties over a long period of time not only for water but also for oils, O / W type emulsions and the like. Further, according to the present disclosure, it is possible to provide a packaging material having the above-mentioned liquid-repellent structure on the side in contact with the article.

FIG. 1 is a cross-sectional view schematically showing an embodiment of the liquid repellent structure according to the present disclosure. FIG. 2 is a cross-sectional view schematically showing another embodiment of the liquid repellent structure according to the present disclosure. FIG. 3 is a cross-sectional view schematically showing another embodiment of the liquid repellent structure according to the present disclosure. FIG. 4 is a diagram showing an image of immersion of a milky lotion in a liquid-repellent structure. FIG. 5 is a diagram showing the concepts of Smr1 and Smr2.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals will be used for the same elements or elements having the same function, and duplicate description will be omitted.

<Liquid repellent structure>
FIG. 1 is a cross-sectional view schematically showing an embodiment of the liquid repellent structure according to the present disclosure. As shown in FIG. 1, the liquid-repellent structure 10A has a base material 1 having a surface to be treated 1a (a surface to be imparted with liquid-repellent property) and a liquid-repellent layer 3A formed on the surface to be treated 1a. And prepare.

(Base material)
The base material 1 is not particularly limited as long as it has a surface to be imparted with liquid repellency and serves as a support. For example, the base material 1 may be in the form of a film (thickness: about 10 to 200 μm) or in the form of a plate. (Thickness: about 1 to 10 mm) may be used. Examples of the film-like base material include paper, resin film, metal foil and the like. By forming the inner surface of the film packaging material made of these materials as the surface to be treated 1a and forming the liquid-repellent layer 3 on the inner surface, it is possible to obtain a packaging bag to which the contents do not easily adhere. Examples of the plate-shaped base material include paper, resin, metal, glass and the like. By forming the inner surface of the container formed by molding these materials as the surface to be treated 1a and forming the liquid-repellent layer 3 on the inner surface, it is possible to obtain a container to which the contents do not easily adhere.

Examples of the paper include high-quality paper, special high-quality paper, coated paper, art paper, cast-coated paper, imitation paper, and kraft paper. Examples of the resin include polyolefin, acid-modified polyolefin, polyester (for example, polyethylene terephthalate (PET)), polyethylene (PE), polypropylene (PP), polyamide (PA), polyvinyl chloride (PVC), cellulose acetate, cellophane resin and the like. Be done. Examples of the metal include aluminum and nickel.

When the base material 1 is in the form of a film, it is preferable that the base material 1 has heat-sealing properties with the liquid-repellent layer 3. Further, when the base layer is interposed between the base material 1 and the liquid-repellent layer 3, as will be described later, it is preferable that the base material 1 has heat-sealing properties with the base layer. The melting point of the base material 1 is preferably 170 ° C. or lower. As a result, when the packaging bag is formed by heat sealing, the adhesion between the base material 1 and the liquid repellent layer 3 becomes stronger, so that the heat sealing property is further improved. From this point of view, it is more preferable that the melting point of the base material 1 is 150 ° C. or lower. The melting point of the base material 1 can be measured by differential scanning calorimetry.

(Liquid repellent layer)
The liquid-repellent layer 3A is a layer having liquid-repellent properties, and has a first filler 5f and a binder resin 5b. The liquid repellent layer 3A is formed so as to cover a part or all of the surface of the base material 1. The liquid repellency is a concept including both water repellency and oil repellency, and specifically, is a property of repelling liquid, semi-solid, or gel-like water-based or oil-based materials. Water-based or oil-based materials include water, oil (salad oil, etc.), yogurt, curry, fresh cream, jelly, pudding, syrup, porridge, soup and other foods, hand soap, body soap, shampoo, rinse and other detergents, and hands. Examples include cosmetics such as creams and emulsions, pharmaceuticals, and chemicals. In the liquid-repellent structure 10, the liquid-repellent layer 3A forms the innermost layer or the outermost layer so that they are in direct contact with each other. The liquid-repellent layer according to the present embodiment repels not only water but also oil, O / W type emulsion (milky lotion, milk, vinaigrette sauce, Hollandaise sauce, buoy base, woodworking adhesive, acrylic paint) and the like for a long period of time. Liquid property (liquid repellent durability) can be maintained.

As shown in FIG. 1, the liquid-repellent layer 3A contains the first filler 5f. The first filler 5f is, for example, spherical, and the average primary particle size thereof is preferably 3 to 1000 nm, and may be 5 to 100 nm or 5 to 20 nm. When the average primary particle diameter of the first filler 5f is 3 nm or more, the first filler tends to form fine irregularities without being buried in the fluorine-containing resin, and when it is 1000 nm or less, the fluorine-containing resin tends to be formed. And the first filler tend to form fine irregularities. The average primary particle size of the first filler is a value obtained by measuring the lengths of the major axis and the minor axis for any total of 10 primary fillers in the field of view of SEM or TEM, and dividing the sum by two. Means the average value.

Examples of the material constituting the first filler 5f include silica, titanium oxide, aluminum oxide, mica, talc, calcium carbonate, barium sulfate, zinc oxide, smectite, zeolite, acrylic resin and the like.

The first filler 5f may be a beaded filler having a structure in which a plurality of primary particles are connected in a beaded shape. The beaded structure of the beaded filler may have a structure in which spherical particles are connected in a chain shape as a branched structure in addition to a structure in which spherical particles are connected in a chain shape. The beaded structure tends to impart flexibility to the liquid-repellent layer due to its three-dimensional structure. The beaded filler can also be called a pearl necklace type filler.

The average particle size (average secondary particle size) of the beaded filler is preferably 50 to 1000 nm, and may be 100 to 400 nm or 100 to 200 nm. When the average particle size of the bead-shaped filler is 50 nm or more, the flexibility of the bead-shaped filler tends to be easily imparted to the liquid-repellent layer, and when the average particle size is 1000 nm or less, the bead-shaped filler tends to form fine irregularities. Tend. The average particle size of the beaded filler is the average value obtained by measuring the major and minor diameters of any 10 beaded fillers in the field of TEM and dividing the sum by two. means.

The content of the first filler 5f in the liquid-repellent layer 3A may be, for example, 20 to 80% by mass, 30 to 75% by mass, or 30 to 50% by mass, based on the total amount of the liquid-repellent layer. You may. When the content of the first filler 5f is within the above range, it becomes easy to suppress the dropping of the first filler 5f, and sufficient unevenness can be imparted to the liquid repellent layer 3A, which is caused by the first filler 5f. It is easy to obtain excellent liquid repellency.

A commercially available product can be used as the first filler 5f. Commercially available silica fillers include, for example, Aerosil made by Nippon Aerosil (AEROSIL50, 90G, 130, 200, 300, 380, etc.), Leolosil made by Tokuyama Corporation (QS-10, 20, 40), and silica made by Shinetsu Silicone. Examples include spherical fine particles QSG, Snowtex series manufactured by Nissan Chemical Co., Ltd. (Snowtex ST-30, PS-S-PO, ST-XS, etc.), 530 and 550 manufactured by Fuji Silysia Chemical Ltd. Examples of commercially available aluminum oxide fillers include AEROXIDE Alu manufactured by Evonik Degussa. Examples of commercially available titanium oxide fillers include AEROXIDE TiO2 manufactured by Evonik Degussa. Examples of commercially available acrylic resin fillers include Epostal manufactured by Nippon Shokubai Co., Ltd. In addition, as commercially available beads-shaped fillers, for example, the HDK series (HDK V15, N20, T30, T40, etc.) manufactured by Asahi Kasei Wacker Silicone Co., Ltd. and the Snowtex series (Snowtex PS-S-PO) manufactured by Nissan Chemical Industries, Ltd. Etc.).

FIG. 2 is a cross-sectional view schematically showing another embodiment of the liquid repellent structure according to the present disclosure. As shown in FIG. 2, the liquid-repellent structure 10B includes a base material 1 having a surface to be treated 1a and a liquid-repellent layer 3B formed on the surface to be treated 1a. As shown in FIG. 2, the liquid-repellent layer 3B may further contain a second filler 6f in addition to the first filler 5f and the binder resin 5b. The second filler 6f is scaly (plate-shaped) and can be called a scaly (plate-shaped) filler. When the filler contains the second filler 6f, the liquid repellent layer 3B may contain an aggregate F of the first filler 5f and the second filler 6f. The first filler 5f, the second filler 6f, and the aggregate F form irregularities on the surface of the liquid repellent layer 3B. The aggregate F is composed of a first filler 5f and a second filler 6f, and a binder resin 5b covering them. The liquid-repellent layer 3B having such a structure has irregularities formed on its surface more efficiently, and it becomes easy to maintain the liquid-repellent property (oil-repellent property) for a long period of time.

The second filler 6f may exist in the form of its primary particles, secondary aggregates or tertiary aggregates. The secondary agglomerates are formed by overlapping a plurality of primary particles of the second filler 6f in parallel orientation. The tertiary agglomerates of the second filler 6f are those in which the primary particles and the secondary agglomerates are irregularly overlapped to grow crystals in each direction.

The average particle size of the second filler 6f is preferably 0.1 to 10 μm, may be 0.1 to 6 μm, or may be 0.1 to 4 μm or 4 to 6 μm. When the average particle size of the second filler 6f is 0.1 μm or more, aggregate F is likely to be formed, while when it is 10 μm or less, the liquid repellency derived from the complicated and fine shape of the second filler 6f. Is fully expressed. The average particle size of the second filler is the average value obtained by measuring the lengths of the major axis and the minor axis for any total of 10 second fillers in the field of view of the SEM and dividing the sum by two. means.

Examples of the material constituting the second filler 6f include silica, mica, aluminum oxide, talc, titanium oxide, calcium carbonate, barium sulfate, zinc oxide, smectite, zeolite, and boron nitride. As a commercially available product of scaly silica, for example, Sun Lovely manufactured by AGC SI-Tech Co., Ltd. can be mentioned. As a commercially available product of scaly mica, for example, Repco mica manufactured by Repco Co., Ltd. can be mentioned. As a commercially available product of scaly aluminum oxide, for example, Cerasur manufactured by Kawai Lime Industry Co., Ltd. can be mentioned. As a commercially available product of scaly boron nitride, for example, ShoBN manufactured by Kawai Lime Industry Co., Ltd. can be mentioned. The second filler 6f may not be treated with a hydrophobic treatment or a liquid repellent treatment.

The content of the second filler 6f in the liquid repellent layer 3B may be, for example, 5 to 100 parts by mass, or 5 to 75 parts by mass, or 5 to 50 parts by mass with respect to 100 parts by mass of the first filler 5f. It may be a mass part. When the content of the second filler 6f is within the above range, it becomes easy to suppress the formation of excessively large aggregates due to the excessive lamination (aggregation) of the primary particles of the second filler 6f. At the same time, excellent liquid repellency due to the first filler 5f and the second filler 6f can be easily obtained.

The plurality of aggregates F may be arranged apart from each other in the liquid repellent layer 3B. That is, a plurality of aggregates F may be arranged in an island shape. Alternatively, a large number of aggregates F may be continuously formed, and a porous layer made of the aggregates F may be formed in the liquid repellent layer 3B. Further, the aggregate F has a complicated shape derived from the complicated and fine shape of the second filler 6f. That is, the aggregate F has a pleated surface and a plurality of primary particles of the second filler 6f (for example, particles having an average primary particle diameter of 0.1 to 6 μm) aggregated in a randomly arranged state. It has a void formed by folds. According to the studies by the present inventors, if the size of one aggregate F ((major axis + minor axis) / 2) is 4 μm or more, the aggregate F greatly contributes to the improvement of the liquid repellent property of the liquid repellent layer.

The binder resin 5b contains at least a fluorine-containing resin. The binder resin 5b may further contain one or both of the thermoplastic resin and the cross-linking agent. When the binder resin 5b contains a cross-linking agent, the binder resin 5b may have a cross-linked structure in which the fluorine-containing resin or the thermoplastic resin is cross-linked via the cross-linking agent in the liquid-repellent layer 3.

The fluorine-containing resin is not particularly limited, and a resin having a structure such as perfluoroalkyl, perfluoroalkenyl, or perfluoropolyether can be appropriately used. The fluorine-containing resin preferably contains a fluorine-acrylic copolymer from the viewpoint of further improving the liquid repellency of the liquid repellent layer 3. The fluorine-acrylic copolymer is a copolymer composed of a fluorine-containing monomer and an acrylic monomer. The fluorine-acrylic copolymer may be a block copolymer or a random copolymer. By using the fluorine-acrylic copolymer, the weather resistance, water resistance, chemical resistance and film forming property of the liquid repellent layer 3 can also be improved.

The fluorine atom concentration on the surface of the liquid-repellent layer obtained by X-ray photoelectron spectroscopy (XPS) can be 35 to 50 atom%, and may be 40 to 45 atom%. When the fluorine atom concentration is at least the lower limit, the surface tension of the liquid-repellent layer can be easily reduced in energy, and the liquid-repellent durability can be easily improved.

The composition analysis in the thickness direction of the surface layer including the surface of the liquid-repellent layer by XPS can be performed under the following analysis conditions using, for example, Quantera-SXM manufactured by ULVAC-PHI Co., Ltd. as an apparatus.
(Analysis conditions)
X-ray source: Al Kα
X-ray beam size: Approximately 20 μmφ
Measurement area: Approximately 20 μmφ
Detection angle: 45 degrees from the sample surface Ions for sputtering: Ar
Acceleration voltage of sputtering ions: 1kV
Raster size of spatter ion: 3 x 3 mm ²
Measurement peaks: F1s, C1s, S2s
No. of Sweps: 3 (F1s), 3 (C1s), 32 (S2s)
Pass Energy: 224eV
Step Size: 0.4eV
Ratio: 2 (F1s), 2 (C1s), 2 (S2s)
Analysis software: MultiPak

As the fluorine-containing resin, a commercially available fluorine-based paint can be used. Commercially available fluorine-based paints include, for example, Asahi Guard manufactured by Asahi Glass Co., Ltd., SF Coat manufactured by AGC Seimi Chemical Co., Ltd., Futergent manufactured by Neos Co., Ltd., Fluorolink manufactured by Solvay Co., Ltd., and Unidyne manufactured by Daikin Kogyo Co., Ltd. Examples thereof include the H-3339 series manufactured by Daiichi Kogyo Seiyaku Co., Ltd. and the Modiper F series manufactured by Nichiyu Co., Ltd.

By using the fluorine-containing resin, it is possible to improve the liquid repellency particularly against oil content and O / W type emulsion. From this point of view, the fluorine-containing resin may not contain structural units derived from pyrrolidone or its derivatives (pyrrolidones). Here, examples of the pyrrolidones include N-vinyl-2-pyrrolidone, N-vinyl-3-methyl-2-pyrrolidone, N-vinyl-5-methyl-2-pyrrolidone, and N-vinyl-3,3-. Examples thereof include dimethyl-2-pyrrolidone. Examples of the fluorine-containing resin containing no structural unit derived from pyrrolidones include Asahi Guard AG-E060, AG-E070, AG-E082, AG-E090 manufactured by Asahi Glass Co., Ltd. and Unidyne TG-manufactured by Daikin Industries, Ltd. 8111 is mentioned.

The thermoplastic resin is not particularly limited, and is, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-α-olefin copolymer, homo, block, random polypropylene, propylene-α-olefin copolymer, or ethylene. -Examples include a vinyl acetate copolymer and the like. For example, in the case of an ethylene-α-olefin copolymer, it can be said to be a block copolymer of propylene and α-olefin, a random copolymer, or the like. Examples of the α-olefin component include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene and the like.

The melting point of the thermoplastic resin is, for example, 50 to 135 ° C. When the melting point is 135 ° C. or lower, the fluorine-containing resin can be easily bleeded out to the surface of the liquid-repellent layer. By bleeding out the fluorine-containing resin to the surface, the surface free energy can be reduced, whereby excellent liquid repellency can be exhibited on the surface of the liquid repellent layer. There is a method of drying the fluorine-containing resin at a high temperature to promote bleed-out, but if the melting point of the thermoplastic resin is too high, a corresponding high temperature is required, which may cause problems such as deformation of the base material 1. There is. On the other hand, when the melting point is 50 ° C. or higher, a certain degree of crystallinity is ensured, so that the occurrence of blocking due to softening is suppressed. From this point of view, it is more preferable that the melting point of the thermoplastic resin is 60 to 120 ° C.

The thermoplastic resin may be a modified polyolefin modified with a predetermined acid. The modified polyolefin is an unsaturated carboxylic acid derivative component derived from, for example, an unsaturated carboxylic acid, an acid anhydride of the unsaturated carboxylic acid, an ester of the unsaturated carboxylic acid, etc., and is obtained by graft-modifying the polyolefin. Further, as the polyolefin, modified polyolefins such as hydroxyl group-modified polyolefins and acrylic-modified polyolefins can also be used. Examples of the modified polyolefin resin include Aurolene manufactured by Nippon Paper Industries Co., Ltd., Zyxen and Sepoljon manufactured by Sumitomo Seika Chemical Co., Ltd., Unitol manufactured by Mitsui Chemicals Co., Ltd., and Arrow Base manufactured by Unitika Ltd.

Since the modified polyolefin has a functional group introduced therein, it is also preferable from the viewpoint that it easily reacts with a cross-linking agent to form a cross-linked structure. Examples of the functional group include a carboxyl group, a hydroxyl group, a (meth) acryloyl group, and an amino group. By using the modified polyolefin having these functional groups together with a cross-linking agent described later, a cross-linked structure composed of a thermoplastic resin, a fluorine-containing resin and a cross-linking agent is formed on the liquid-repellent layer 3, and the liquid-repellent layer has better durability. It can be applied to the layer 3.

The cross-linking agent preferably has a functional group that reacts with the fluorine-containing resin. As such a cross-linking agent, for example, a cross-linking agent having a functional group such as an aziridine group, an isocyanate group, a carbodiimide group, or an amino group can be used. Examples of commercially available cross-linking agents include Chemitite manufactured by Nippon Shokubai Co., Ltd., Takenate manufactured by Mitsui Chemicals, Inc., Carbodilite manufactured by Nisshinbo Chemical Co., Ltd., Meikanate manufactured by Meisei Chemical Works, Ltd., and Cymel manufactured by Cytec Industries, Ltd. ).

The fluorine-containing resin is generally used as an aqueous dispersion dispersed in water. Therefore, most of the fluorine-containing resins have hydrophilic groups such as hydroxyl groups and amino groups in order to enhance the affinity with water. By using a cross-linking agent having a functional group that reacts with the fluorine-containing resin, these functional groups of the fluorine-containing resin react with the functional groups of the cross-linking agent to form a cross-linked structure in the liquid-repellent layer. Become. Further, since these functional groups of the fluorine-containing resin are reduced by reacting with the cross-linking agent, the functional groups remaining in the liquid-repellent layer are reduced. Therefore, even when the liquid-repellent layer comes into contact with the liquid material for a long period of time, the decrease in the liquid-repellent property can be suppressed, and the excellent liquid-repellent property can be maintained for a long period of time. When the fluorine-containing resin is used as a dispersion dispersed in a solvent other than water, the fluorine-containing resin has a structure (for example, a hydrocarbon chain or the like) for enhancing the affinity with the solvent used. May be good.

The content of the fluorine-containing resin in the binder resin 5b (based on the mass of the binder resin 5b) is, for example, 5% by mass or more, and may be 15% by mass or more or 50% by mass or more. The content of the fluorine-containing resin in the binder resin 5b may be 100% by mass, but when the binder resin 5b contains a thermoplastic resin or a cross-linking agent, the content of the fluorine-containing resin may be 99% by mass or less. It may be 75% by mass or less. When the content of the fluorine-containing resin in the binder resin 5b is 5% by mass or more, the liquid-repellent layer tends to exhibit excellent liquid-repellent properties, while when it is 99% by mass or less, the thermoplastic resin or the cross-linking agent The content can be sufficiently secured, the filler can be sufficiently suppressed from falling off from the liquid-repellent layer, and the durability of the liquid-repellent layer can be sufficiently enhanced.

The content of the thermoplastic resin in the binder resin 5b (based on the mass of the binder resin 5b) is, for example, 5 to 90% by mass, and may be 10 to 50% by mass or 20 to 30% by mass. When the content of the thermoplastic resin in the binder resin 5b is 5% by mass or more, it is possible to sufficiently suppress the filler from falling off from the liquid-repellent layer, while when it is 90% by mass or less, the fluorine-containing resin And the content of the cross-linking agent can be sufficiently secured, and the liquid-repellent layer tends to exhibit excellent liquid-repellent properties and durability.

The ratio _WC / _WJ of the mass _WC of the cross-linking agent contained in the binder resin 5b and the mass WJ of the fluorine-containing resin contained in the binder resin _5b is, for example, 0.01 to 0.5, which is 0. It may be 0.05 to 0.3 or 0.1 to 0.2. When the ratio _WC / _WJ is 0.01 or more, it is possible to sufficiently suppress the filler from falling off from the liquid-repellent layer, and it is possible to sufficiently enhance the durability of the liquid-repellent layer. On the other hand, when the ratio _WC / _WJ is 0.5 or less, the content of the fluorine-containing resin can be sufficiently secured, and the fluorine-containing resin can be sufficiently bleeded out to the surface of the liquid-repellent layer. Good liquid repellency can be exhibited.

The ratio _WB / _WS of the mass _WB of the binder resin 5b contained in the liquid-repellent layer to the mass _WS of the filler may be 0.1 to 5, 0.2 to 2 or 0.3 to 0.3. It may be 1. Here, the mass _WB of the binder resin 5b corresponds to the total mass of the mass _WJ of the fluorine-containing resin, the mass _WP of the thermoplastic resin contained in some cases, and the mass _WC of the cross-linking agent. When the ratio _WB / _WS is within the above range, an uneven structure due to the filler is likely to be formed on the surface of the liquid-repellent layer even though the entire filler is sufficiently covered with the binder resin 5b. As a result, it is possible to prevent the filler from falling off from the liquid-repellent layer, and to enjoy both the liquid-repellent property due to the filler and the liquid-repellent property due to the fluorine-containing resin contained in the binder resin 5b. Since the mass _WS of the filler does not substantially change even when the liquid-repellent layer 3 is burned, the value of the ratio _WB / _WS is measured by measuring the change in mass due to the combustion of the liquid-repellent layer. It can be calculated from the value.

The mass per unit area of the liquid repellent layer is, for example, 0.3 to 10.0 g / m ² , 1.0 to 3.0 g / m ² or 1.5 to 2.5 g / m ² . May be good. When the mass of the liquid-repellent layer per unit area is 0.3 g / m ² or more, excellent liquid-repellent properties due to the fluorine-containing resin can be achieved. On the other hand, when the mass of the liquid-repellent layer per unit area is 10.0 g / m ² or less, the uneven structure and the liquid-repellent effect of the fluorine-containing resin can be efficiently obtained.

The liquid-repellent layer may contain other additives, if necessary, to the extent that the liquid-repellent function is not impaired. Examples of other additives include flame retardants, slip agents, anti-blocking agents, antioxidants, light stabilizers, tackifiers and the like.

The liquid-repellent layer may not contain structural units derived from pyrrolidones, particularly from the viewpoint of further improving the oil content and the liquid-repellent property of the O / W type emulsion. That is, the structural unit derived from pyrrolidones may not be contained not only in the fluorine-containing resin but also in any of the other components constituting the liquid-repellent layer. The presence or absence of structural units derived from pyrrolidones in the liquid-repellent layer can be determined by infrared spectroscopy, nuclear magnetic resonance spectroscopy, thermal decomposition GC-MS, or the like.

In the above embodiment, the case where the liquid-repellent layer is formed in direct contact with the surface to be treated 1a of the base material 1 is exemplified, but the base layer is formed on the surface to be treated 1a of the base material 1. , A liquid-repellent layer may be formed on the base layer. The base layer is a layer arranged between the base material 1 and the liquid-repellent layer, and can be formed so as to cover a part or all of the surface (processed surface 1a) of the base material 1. By interposing the base layer between the base material 1 and the liquid-repellent layer, the adhesion between the base material 1 and the liquid-repellent layer can be improved. Further, by providing the base layer, the liquid repellency of the liquid repellent structure can be further improved.

FIG. 3 is a cross-sectional view schematically showing another embodiment of the liquid repellent structure according to the present disclosure. As shown in FIG. 3, the liquid-repellent structure 10C has a base material 1 having a surface to be treated 1a, a base layer 2 formed on the surface to be treated 1a, and a liquid-repellent layer 3C on the base layer 2. And prepare. The underlayer contains a thermoplastic resin 7b and a third filler 7f. The liquid-repellent layer 3C may contain the first filler 5f and the binder resin 5b as shown in FIG. 1, and in addition to the first filler 5f and the binder resin 5b as shown in FIG. It may contain two fillers 6f. FIG. 3 shows the former aspect as an example. By providing the base layer 2 under the liquid-repellent layer 3C, unevenness is formed more efficiently on the surface thereof, and it becomes easy to maintain the liquid-repellent property for a long period of time.

(Underground layer)
The base layer can be formed of a resin similar to the thermoplastic resin used for the liquid repellent layer. Specific embodiments of the thermoplastic resin are as described above.

The base layer may contain a third filler having an average primary particle size of 5 to 60 μm. The material of the third filler is an inorganic material such as silica, talc, mica, titanium oxide, calcium carbonate, barium sulfate, zinc oxide, smectite, zeolite, aluminum oxide, silicone, acrylic resin, urethane resin, and polyolefin resin (polypropylene). , Polyethylene) and other resin materials. By containing the third filler, rough irregularities can be formed on the surface of the base layer, and by providing the liquid repellent layer on the surface, rough and complicated irregularities can be formed by the liquid repellent structure. can. As a result, the liquid repellency can be further improved. From this point of view, the average primary particle size of the third filler may be 10 to 50 μm and may be 20 to 50 μm.

Examples of the third filler include Sunsphere (silica) manufactured by AGC SI Tech Co., Ltd., Silicone powder KMP series (silicone) manufactured by Shinetsu Chemical Industry Co., Ltd., Ganz Pearl (acrylic resin) manufactured by Aika Kogyo Co., Ltd., and Negami Kogyo. Art Pearl (acrylic resin) manufactured by Negami Kogyo Co., Ltd., Flow beads (polyethylene resin) manufactured by Sumitomo Seika Co., Ltd., Flow beads (polypropylene resin) manufactured by Sumitomo Seika Co., Ltd. ), Miperon (ultra-high molecular weight polyethylene) manufactured by Mitsui Kagaku Co., Ltd., and the like.

The base layer can impart coarse irregularities to the liquid-repellent structure. Since the coarse unevenness facilitates point contact between the liquid-repellent layer and the contents, deterioration of the liquid-repellent property can be further suppressed. The surface roughness Sa of the liquid-repellent structure may be 1.5 to 15.0 μm because the effect of point contact is sufficiently easy to obtain and the contents are difficult to be taken into the recesses. It may be 0 to 14.0 μm, and may be 5.0 to 10.0 μm.

The ratio W _BU / W _SU of the mass _WBU of the thermoplastic resin contained in the base layer to the mass W _SU of the third filler may be 0.1 to 1, and may be 0.2 to 0.5. You may. When the ratio W _BU / W _SU is within the above range, the removal of the third filler is suppressed, but a coarse uneven structure due to the third filler is likely to be formed. The value of the ratio W _BU / W _SU can be easily adjusted by the amount of the paint charged. The value of the ratio W _BU / W _SU can also be calculated from the measured value by measuring the change in mass due to the combustion of the underlying layer.

The mass per unit area of the base layer is, for example, 1.0 to 20.0 g / m ² , and may be 3.0 to 10.0 g / m ² . When the mass per unit area of the base layer is 1.0 g / m ² or more, it becomes easy to achieve excellent liquid repellency. On the other hand, when the mass per unit area of the base layer is 20.0 g / m ² or less, it becomes easy to sufficiently obtain the effect of point contact.

(Surface texture of liquid-repellent structure)
The load area ratio Smr2 that separates the protruding valley portion and the core portion of the liquid repellent layer surface obtained by the three-dimensional surface roughness analysis is divided by the load area ratio Smr1 that separates the protruding peak portion and the core portion of the liquid repellent layer surface. The value Smr2 / Smr1 is 5 or less. Thereby, excellent liquid repellent durability can be obtained. FIG. 4 is a diagram showing an image of immersion of a milky lotion in a liquid-repellent structure. The figure (a) shows the uneven cross-sectional shape when Smr2 / Smr1 is more than 5, and the figure (b) shows the uneven cross-sectional shape when Smr2 / Smr1 is 5 or less, and the inferred immersion image of the emulsion for each uneven cross-sectional shape. Is shown. In FIG. 3A, the milky lotion L has entered the recess on the surface of the liquid-repellent structure 10. In FIG. 3B, the milky lotion L does not enter the recess on the surface of the liquid-repellent structure 10. Even if the liquid has a high leveling property and a high viscosity such as a milky lotion, it is presumed that if Smr2 / Smr1 is 5 or less, the milky lotion is difficult to enter into the recess and the milky lotion easily flows down. It is considered that this ensures excellent liquid repellent durability.

Smr2 / Smr1 may be 4.5 or less, 4 or less, and 3.5 or less. Further, the lower limit of Smr2 / Smr1 can be 1.67 and may be 2 or more. From the viewpoint of the shape of the convex portion, Smr1 can be 20 to 60, and may be 30 to 60.

The values of Smr1, Smr2 and Smr2 / Smr1 can be adjusted, for example, by adjusting the degree of dispersion of the particles. For example, the value of Smr2 / Smr1 can be increased by dispersing glass beads using a locking shaker (for example, manufactured by Seiwa Giken Co., Ltd.) or by strong stirring using a normal stirrer, while by low stirring using a normal stirrer. , Smr2 / Smr1 can be reduced.

The load area ratios Smr1 and Smr2 are parameters defined in JIS B0681-2. FIG. 5 is a diagram showing the concepts of Smr1 and Smr2. The vertical axis is the height of the surface unevenness, and the horizontal axis is the total area (load area ratio) when the surface unevenness is cut at each height. The surface load curve is a curve representing the height from 0% to 100% of the load area ratio. As shown in the figure, in the central part of the load curve for the roughness curve, the straight line where the division line of the load curve drawn with the difference ΔSmr of the load area ratio Smr set to 40% has the gentlest slope is taken as the equivalent straight line. When the core part (Sk in the figure) is between the two height positions where the equivalent straight line intersects the vertical axis at the positions where the load area ratio is 0% and 100%, the load curve of _Smr1 is the protruding mountain part. The load area ratio at the point where it intersects the boundary line with the core part. Similarly, Smr2 refers to the load area ratio at the point where the load curve intersects the boundary line between the protruding valley portion and the core portion.

<Manufacturing method of liquid-repellent structure>
A method for manufacturing a liquid-repellent structure will be described. The manufacturing method according to the present embodiment includes a step of preparing a coating liquid for forming a liquid-repellent layer, a step of forming a coating liquid coating on the surface to be treated of the base material, and drying and curing the coating film. It is provided with a step of forming a liquid-repellent layer. Hereinafter, each step will be described.

First, a coating liquid containing a filler, a fluorine-containing resin, a solvent, a thermoplastic resin if necessary, and a cross-linking agent if necessary is prepared. Examples of the solvent include water, alcohol, organic solvents and the like. The blending amount (solid content) of each component in the coating liquid may be appropriately adjusted so that the content of each component in the liquid-repellent layer becomes as described above. At this time, the degree of dispersion of the particles is adjusted so that the Smr2 / Smr1 is 5 or less. The thermoplastic resin may be in the form of an emulsion dispersed in water, alcohol or the like. Such a polyolefin emulsion may be prepared by a method of emulsifying a polymer produced by a polymerization reaction of a corresponding monomer or the like, or may be prepared by emulsifying and polymerizing a corresponding monomer.

The obtained coating liquid is applied onto the substrate. As the coating method, a known method can be used without particular limitation, and examples thereof include a dipping method (dipping method); a method using a spray, a coater, a printing machine, a brush, or the like. The types of coaters and printing machines used in these methods and their coating methods include gravure coaters such as direct gravure method, reverse gravure method, kiss reverse gravure method, and offset gravure method, reverse roll coater, and micro gravure. Examples include coaters, chamber doctor combined coaters, air knife coaters, dip coaters, bar coaters, comma coaters, and die coaters. The amount of the coating liquid applied can be appropriately adjusted so that the mass per unit area of the above-mentioned liquid-repellent layer can be obtained.

The coating film formed on the substrate is dried and cured by heating. This makes it possible to obtain a liquid-repellent structure including a base material and a liquid-repellent layer provided on the base material. When the coating liquid contains a cross-linking agent, a cross-linked structure composed of a fluorine-containing resin, a thermoplastic resin used as necessary, and a cross-linking agent is formed on the liquid-repellent layer. The heating conditions are not limited as long as the solvent can be volatilized and a crosslinking reaction can occur, but the heating conditions can be, for example, 60 to 100 ° C. for 0.5 to 5 minutes.

When the liquid-repellent structure further includes a base layer, the manufacturing method according to the present embodiment includes a step of preparing a coating liquid for forming the base layer and a coating liquid for forming the liquid-repellent layer, and a treatment of the base material. A step of forming a coating liquid for forming an undercoat layer on a surface, a step of forming an undercoat layer by drying and curing the coating film, and forming a coating film of a coating liquid for forming a liquid-repellent layer. It comprises a step and a step of forming a liquid repellent layer by drying and curing the coating film. The preparation and application of the coating liquid for forming the base layer and the drying and curing of the coating film can be carried out according to the description of the preparation and application of the coating liquid for forming the base layer and the drying and curing of the coating film.

<Packaging material>
The packaging material according to the present embodiment has a liquid-repellent structure on the side in contact with the article. The packaging material according to the present embodiment shall be applied to an article containing water (for example, water, beverage, yogurt), an article containing oil (for example, salad oil, curry, fresh cream), and an article containing an O / W type emulsion. Can be done. Specific aspects of the packaging material include retort pouches for curry and pasta sauce, containers and lids for yogurt and pudding, milky lotions, hand soaps, shampoos, toiletry containers such as rinses, refill pouches for these, and toothpaste. And tubes for pharmaceuticals.

The present disclosure will be described in more detail with reference to the following experimental examples, but the present disclosure is not limited to these examples.

The following materials were prepared in order to prepare the liquid-repellent structure according to the experimental example.
(Base material)
-Polyethylene terephthalate (PET) film (fluorine-containing resin)
Asahi Guard AG-E060 (trade name, manufactured by Asahi Glass Co., Ltd., fluorine-acrylic copolymer having no structural unit derived from pyrrolidones, cationic water-based material)
Asahi Guard AG-E070 (trade name, manufactured by Asahi Glass Co., Ltd., fluorine-acrylic copolymer having no structural unit derived from pyrrolidones, cationic water-based material)
Asahi Guard AG-E082 (trade name, manufactured by Asahi Glass Co., Ltd., fluorine-acrylic copolymer having no structural unit derived from pyrrolidones, cationic water-based material)
Asahi Guard AG-E090 (trade name, manufactured by Asahi Glass Co., Ltd., fluorine-acrylic copolymer having no structural unit derived from pyrrolidones, anionic water-based material)
-Unidyne TG-8111 (trade name, manufactured by Daikin Industries, Ltd., fluorine-acrylic copolymer having no structural unit derived from pyrrolidones, aqueous material of cation)
-Unidyne TG-8811 (trade name, manufactured by Daikin Industries, Ltd., a fluorine-acrylic copolymer having a structural unit derived from pyrrolidones, an aqueous material of a cation)
(First filler)
・ AEROSIL50 (trade name, manufactured by Nippon Aerosil Co., Ltd., spherical filler)
・ AEROSIL200 (trade name, manufactured by Nippon Aerosil Co., Ltd., spherical filler)
・ AEROSIL300 (trade name, manufactured by Nippon Aerosil Co., Ltd., spherical filler)
・ AEROSIL380 (trade name, manufactured by Nippon Aerosil Co., Ltd., spherical filler)
・ Snowtex ST-30 (trade name, manufactured by Nissan Chemical Industries, Ltd., spherical filler)
・ HDK V15 (trade name, manufactured by Asahi Kasei Wacker Silicone Co., Ltd., beaded filler)
・ HDK N20 (trade name, manufactured by Asahi Kasei Wacker Silicone Co., Ltd., beaded filler)
・ HDK T30 (trade name, manufactured by Asahi Kasei Wacker Silicone Co., Ltd., beaded filler)
・ HDK T40 (trade name, manufactured by Asahi Kasei Wacker Silicone Co., Ltd., beaded filler)
(Second filler)
・ Sun Lovely (trade name, manufactured by AGC Si-Tech Co., Ltd., scaly filler, average particle size 4 to 6 μm)
・ Sun Lovely LFS (trade name, manufactured by AGC Si-Tech Co., Ltd., scaly filler, average particle size 4 to 6 μm)
・ Show BN UHP-S2 (trade name, manufactured by Showa Denko KK, scaly filler, average particle size 0.5-0.9 μm)
・ Showa N UHP-1K (trade name, manufactured by Showa Denko KK, scaly filler, average particle size 6-10 μm)
(Third filler)
-Art Pearl SE-010T (trade name, manufactured by Negami Kogyo Co., Ltd., crosslinked acrylic resin particles, average primary particle diameter 10 μm)
-Art Pearl SE-020T (trade name, manufactured by Negami Kogyo Co., Ltd., crosslinked acrylic resin particles, average primary particle diameter 20 μm)
-Art Pearl SE-030T (trade name, manufactured by Negami Kogyo Co., Ltd., crosslinked acrylic resin particles, average primary particle diameter 30 μm)
-Art Pearl SE-050T (trade name, manufactured by Negami Kogyo Co., Ltd., crosslinked acrylic resin particles, average primary particle diameter 50 μm)
(Thermoplastic resin)
-Aurolen AE-301 (trade name, manufactured by Unitika Ltd., modified polyolefin resin)
・ Zyxen AC (trade name, manufactured by Nippon Paper Industries, Ltd., modified polyolefin resin)
-Seporjon VA406N (trade name, manufactured by Sumitomo Seika Chemical Co., Ltd., modified polyolefin resin)
-Arrow base SB5230N (trade name, manufactured by Unitika Ltd., modified polyolefin resin)
(solvent)
・ Alcohol solvent (2-propanol)

<Preparation of liquid-repellent structure (without base layer)>
Each component was added to the solvent so that the composition of the liquid repellent layer was as shown in Tables 1 to 3. This was sufficiently stirred to prepare a coating liquid for forming a liquid-repellent layer, and the coating liquid was applied onto a PET film as a base material using a bar coater. Then, the applied coating liquid was heated at 80 ° C. for 1 minute to dry and harden, and a liquid-repellent layer was formed on the substrate. The coating amount was adjusted so that the mass per unit area of the liquid-repellent layer was 1.8 g / m ² .

<Preparation of liquid-repellent structure (with base layer)>
Each component was added to the solvent so that the composition of the underlayer was as shown in Tables 1 to 3. This was sufficiently stirred to prepare a coating liquid for forming an underlayer, and the coating liquid was applied onto a PET film as a base material using a bar coater. Then, the applied coating liquid was heated at 80 ° C. for 1 minute to dry and cure, and a base layer was formed on the substrate. The coating amount was adjusted so that the mass per unit area of the base layer was 6.0 g / m ² . Then, a liquid-repellent layer was formed on the base layer in the same manner as in the case of no base layer.

<Evaluation of liquid-repellent structure>
The liquid-repellent structure was evaluated from the following viewpoints. The evaluation results are shown in Tables 4-6.

(Evaluation of surface properties)
JIS B0681-2 Product Geometric Characteristics Specifications (GPS) -Surface texture: 3D-Part 2: Arithmetic mean height (Sa) of contour surface described in 4.1.7 items of terms, definitions and surface texture parameters. The load area ratio (Smr1 and Smr2) described in 4.4.4 items was measured. When the sample was tilted, Sa was measured by three-dimensional measurement after performing surface correction (tilt correction). Arbitrary three points of the liquid-repellent structure were measured, the average value was taken as the surface roughness Sa, and the load area ratio ratio Smr2 / Smr1 was calculated.
Measuring equipment: Olympus OLS4000 (laser microscope)
Measurement magnification: x20
Measurement mode: Multi-layer

(Fluorine atom concentration on the surface of the liquid repellent layer)
The fluorine atom concentration on the surface of the liquid repellent layer was measured by X-ray photoelectron spectroscopy (XPS). A Quantera-SXM manufactured by ULVAC-PHI was used as an apparatus, and the analysis was performed under the following analytical conditions.
(Analysis conditions)
X-ray source: Al Kα
X-ray beam size: Approximately 20 μmφ
Measurement area: Approximately 20 μmφ
Detection angle: 45 degrees from the sample surface Ions for sputtering: Ar
Acceleration voltage of sputtering ions: 1kV
Raster size of spatter ion: 3 x 3 mm ²
Measurement peaks: F1s, C1s, S2s
No. of Sweps: 3 (F1s), 3 (C1s), 32 (S2s)
Pass Energy: 224eV
Step Size: 0.4eV
Ratio: 2 (F1s), 2 (C1s), 2 (S2s)
Analysis software: MultiPak

(Evaluation of liquid repellency)
The liquid-repellent structure was placed flat so that the surface on the liquid-repellent layer side was facing up, and 2 μL of the following liquid was dropped onto the liquid-repellent layer with a dropper. Then, the liquid-repellent structure was erected vertically and allowed to stand for 30 seconds as it was, and the state of the dropped liquid was visually observed. From the observation results, the liquid repellency was evaluated based on the following evaluation criteria. If the evaluation result is 2 or more, it can be said that there is no practical problem. The evaluation result is preferably 3 or more.
[Liquid used]
Pure water yogurt: Meiji Bulgaria yogurt L81 low sugar (Meiji)
Salad oil: Nisshin salad oil (Nisshin Oilio)
Curry (normal temperature): Bon Curry Gold Medium spicy (Otsuka Foods)
Emulsion: Emulsion containing soy milk isoflavone (Smooth Honpo)
[Evaluation criteria]
5: The droplets were rounded and rolled off from the water-repellent layer. Or it came off.
4: It flowed down from the liquid-repellent layer, and no trace of the flow remained.
3: It flowed down from the liquid-repellent layer, but the traces of the flow remained in dots.
2: It flowed down from the liquid-repellent layer, but the traces of the flow remained linear.
1: It stayed on the liquid repellent layer and did not move. Or it soaked into the liquid repellent layer.

(Durability evaluation)
The liquid-repellent structure was cut into a size of 50 mm in width and 100 mm in length to obtain a test piece. 150 ml of each of the liquids used in the liquid repellency evaluation was poured into a 200 ml beaker, the test piece was immersed in the liquid to half the length, and left at room temperature (25 ° C.) for 5 days. After standing, the test piece is pulled up from the liquid, and the state of adhesion of each liquid to the surface of the immersion part of the liquid-repellent structure on the side where the liquid-repellent layer is formed is visually observed, and the durability is based on the following evaluation criteria. (Liquid repellency after long-term contact with each liquid) was evaluated. If the evaluation result is 2 or more, it can be said that there is no practical problem. The evaluation result is preferably 3 or more.
[Evaluation criteria]
5: No liquid adhesion was observed in the immersed portion.
4: Liquid adhesion was observed in an area of less than 10% of the immersed portion.
3: Liquid adhesion was observed in an area of 10% or more and less than 30% of the immersed portion.
2: Liquid adhesion was observed in an area of 30% or more and less than 70% of the immersed portion.
1: Liquid adhesion was observed in an area of 70% or more of the immersed portion.

It was found that the liquid-repellent structures of Experimental Examples 1 to 57 having the configuration of the present disclosure have excellent liquid-repellent properties over a long period of time.

1 ... Substrate, 1a ... Surface to be treated (surface to which liquid repellency should be imparted), 2 ... Underlayer, 3A, 3B, 3C ... Liquid repellent layer, 5b ... Binder resin, 5f ... First filler, 6f ... Two fillers, 7b ... thermoplastic resin, 7f ... third filler, F ... aggregates, 10,10A, 10B, 10C ... liquid repellent structures, L ... emulsion.

Claims (9)

A liquid-repellent structure comprising a surface to be imparted with liquid-repellent properties and a liquid-repellent layer formed on the surface.
The liquid-repellent layer contains a binder resin containing a fluorine-containing resin and a filler dispersed in the binder resin.
The load area ratio Smr2 that separates the protruding valley portion and the core portion of the liquid repellent layer surface, which is obtained by the three-dimensional surface roughness analysis, is the load area ratio Smr1 that separates the protruding peak portion and the core portion of the liquid repellent layer surface. A liquid-repellent structure having a value Smr2 / Smr1 divided by 5 or less. The liquid-repellent structure according to claim 1, wherein the fluorine atom concentration on the surface of the liquid-repellent layer is 35 to 50 atom%, which is obtained by X-ray photoelectron spectroscopy. The liquid-repellent structure according to claim 1 or 2, wherein the filler contains a first filler having a structure in which a plurality of primary particles are connected in a bead shape. The liquid-repellent structure according to any one of claims 1 to 3, wherein the fluorine-containing resin contains a fluorine-acrylic copolymer. The liquid-repellent structure according to any one of claims 1 to 4, wherein the filler contains a scaly second filler. An underlayer is further provided between the surface and the liquid repellent layer.
The liquid-repellent structure according to any one of claims 1 to 5, wherein the base layer contains a thermoplastic resin and a third filler having an average primary particle diameter of 5 to 60 μm. The liquid-repellent structure according to claim 6, wherein the surface roughness Sa is 1.5 to 15.0 μm. A packaging material having the liquid-repellent structure according to any one of claims 1 to 7 on the side in contact with the article. The packaging material according to claim 8, wherein the article contains at least one of an oil component and an O / W type emulsion.

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