Liquid-repellent structure and packaging material

Abstract

To provide a liquid-repellent structure which has excellent liquid-repellency against water and excellent liquid-repellency against oil or a liquid material containing the oil.SOLUTION: A liquid-repellent structure is structured so that a substrate layer 2 and a liquid-repellent layer 3 are subsequently laminated on a surface to which liquid-repellency is imparted. The substrate layer contains a first filler 2F, the liquid-repellent layer 3 contains a fluorine-containing resin and a second filler 3Fα, and glossiness at a measurement angle of 60 degrees on the surface of the liquid-repellent layer is within a range of 1.5-5.0 GU.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a liquid-repellent structure and a packaging material having this liquid-repellent structure on a side that comes into contact with an article. [Background technology]

[0002] Various aspects of water-repellent structures are known. For example, Patent Document 1 discloses a water-repellent structure in which a fine particle layer in which scale-like inorganic fine particles are fixed by a binder resin and a water-repellent film layer covering the surface of the fine particle layer are provided on the surface of a substrate. Patent Document 2 discloses a single-layer water-repellent heat seal film containing a thermoplastic resin and hydrophobic particles. Patent Document 3 discloses that in a water-repellent laminate for a lid material comprising a substrate and a thermal adhesive layer on the substrate, the thermal adhesive layer contains a thermoplastic resin, water-repellent fine particles, and bead particles having an average particle size larger than that of the water-repellent fine particles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-132055 A [Patent Document 2] JP 2017-155183 A [Patent Document 3] International Publication No. 2017 / 204258 Summary of the Invention [Problem to be solved by the invention]

[0004] In the inventions described in Patent Documents 1 to 3, water repellency is evaluated based on the contact angle with a water droplet. In the inventions described in Patent Documents 2 and 3, yogurt repellency (adhesion of yogurt) is also evaluated. However, in the inventions described in these documents, liquid repellency against viscous liquids containing oil (e.g., curry, mayonnaise) is not considered.

[0005] An object of the present disclosure is to provide a liquid-repellent structure that has excellent liquid repellency against water as well as against oil or a viscous liquid material containing oil, etc. Another object of the present disclosure is to provide a packaging material having the liquid-repellent structure on the side that comes into contact with an article. [Means for solving the problem]

[0006] That is, the invention described in claim 1 is a method for forming a liquid-repellent layer on a surface to be imparted with liquid repellency. A liquid repellent structure formed by laminating The underlayer contains a first filler, the liquid-repellent layer contains a fluorine-containing resin and a second filler, The gloss of the liquid-repellent layer surface at a measurement angle of 60 degrees is within a range of 1.5 to 5.0 GU. the law of nature, the second filler is a spherical filler, The liquid repellent layer further contains a scale-like filler, The first filler has an average primary particle size in the range of 5 to 30 μm; The average primary particle size of the second filler is within a range of 10 to 100 nm; The average primary particle diameter of the scaly filler is within the range of 4 to 6 μm. The liquid repellent structure is characterized in that

[0007] Next, the invention described in claim 2 is as follows: The weight of the scaly filler divided by the weight of the spherical filler is within a range of 0.05 to 0.30. 2. The liquid repellent structure according to claim 1,

[0008] Next, the invention described in claim 3 is as follows: The first filler is larger than the second filler. The present invention is characterized in that 1 or 2 It is a liquid repellent structure described in .

[0009] Next, the invention described in claim 4 is as follows: The liquid repellent structure according to any one of claims 1 to 3 is provided on a side that comes into contact with an article. Characterized by packaging material It is. Effect of the Invention

[0012] Glossiness is a concept related to unevenness at the wavelength level of visible light. As will be seen from the examples and comparative examples described below, when this glossiness is within the range of 1.5 to 5.0 GU, excellent liquid repellency is exhibited not only against water but also against viscous liquids containing oil (e.g. mayonnaise). [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view that illustrates a specific example of a liquid-repellent structure according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, specific examples of the present disclosure will be described with reference to the accompanying drawings. Fig. 1 shows a specific example of a liquid repellent structure 10 according to the present invention.

[0015] As can be seen from this figure, the liquid-repellent structure 10 comprises a substrate 1 having a surface to be treated (a surface to which liquid repellency is to be imparted), and an undercoat layer 2 and a liquid-repellent layer 3 formed in this order on the surface to be treated.

[0016] The gloss of the surface of this liquid-repellent layer 3 at a measurement angle of 60 degrees must be within the range of 1.5 to 5.0 GU. As will be seen from the examples and comparative examples described later, whether the gloss is greater than or less than this range, the liquid repellency is poor. In particular, the property (peeling ability) of repelling viscous liquids containing oil such as mayonnaise and preventing their adhesion is poor. In contrast, when the gloss is within this range, the layer exhibits excellent liquid repellency against water and oil, and also exhibits excellent liquid repellency against viscous liquids containing oil (e.g. mayonnaise).

[0017] Since the gloss level varies depending on the composition and coating amount of the undercoat layer 2 and the liquid-repellent layer 3, the gloss level of the surface of the liquid-repellent layer 3 can be set within the above range by appropriately controlling the composition and coating amount of each of these layers. Each layer, including the substrate 1, will now be described in order.

[0018] (base material) The substrate 1 is not particularly limited as long as it has a surface to be imparted with liquid repellency and serves as a support, and may be, for example, a film (thickness: about 10 to 200 μm) or a plate (thickness: about 1 to 10 mm). Examples of film-shaped substrates include paper, resin film, metal foil, etc. By using the inner surface of a film packaging material made of these materials as the treatment surface and sequentially forming a base layer 2 and a liquid repellent layer 3 on this, a packaging bag to which the contents do not easily adhere can be obtained. Examples of plate-shaped substrates include paper, resin, metal, glass, etc.

[0019] Furthermore, by forming the undercoat layer 2 and the liquid-repellent layer 3 on the inner surface of a container molded from these materials, a container to which the contents do not easily adhere can be obtained.

[0020] Examples of the paper include fine paper, special fine paper, coated paper, art paper, cast coated paper, imitation paper, craft paper, etc. Examples of the resin include polyolefin, acid-modified polyolefin, polyester (e.g., polyethylene terephthalate (PET)), polyethylene (PE), Examples of the material include polypropylene (PP), polyamide (PA), polyvinyl chloride (PVC), cellulose acetate, cellophane resin, etc. Examples of the metal include aluminum and nickel.

[0021] (base layer 2) The underlayer 2 is a layer disposed between the substrate 1 and the liquid-repellent layer 3, and is formed so as to cover a part or the whole of the surface to be treated of the substrate 1. By interposing the underlayer between the substrate 1 and the liquid-repellent layer 3, it is possible to increase the adhesion between the substrate 1 and the liquid-repellent layer 3. Furthermore, by providing the underlayer 2, it is possible to further improve the liquid repellency of the liquid-repellent structure.

[0022] The underlayer 2 contains at least a thermoplastic resin 2R.

[0023] The thermoplastic resin 2R is not particularly limited, and examples thereof include low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-α-olefin copolymer, homo, block, or random polypropylene, propylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, etc. For example, an ethylene-α-olefin copolymer can be called a block copolymer or random copolymer of propylene and α-olefin. Examples of the α-olefin component include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and 4-methyl-1-pentene.

[0024] The thermoplastic resin 2R may be a modified polyolefin modified with a specific acid. The modified polyolefin is obtained by graft-modifying a polyolefin with an unsaturated carboxylic acid derivative component derived from, for example, an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like. In addition, modified polyolefins such as hydroxyl-modified polyolefins and acrylic-modified polyolefins can also be used as the polyolefin. Examples of modified polyolefin resins include Auroren manufactured by Nippon Paper Industries Co., Ltd., ZAIXXEN manufactured by Sumitomo Seika Chemicals Co., Ltd., UNISTOLE manufactured by Mitsui Chemicals, Inc., and ARROWBASE manufactured by Unitika Ltd.

[0025] As shown in FIG. 1, the underlayer 2 must contain a first filler 2F. The first filler 2F is preferably larger than the second filler 3Fβ contained in the liquid-repellent layer 3. When the underlayer 2 contains the first filler 2F having such a large particle size, the surface of the underlayer 2 is formed with unevenness based on the first filler 2F, and the liquid-repellent layer 3 is provided along the unevenness of the surface of the underlayer 2. This makes it possible to make the unevenness of the surface of the liquid-repellent layer 3 large and complex, thereby reducing the glossiness and enhancing the liquid repellency. The average primary particle size of the first filler 2F is preferably within the range of 5 to 30 μm.

[0026] As the first filler 2F, for example, the following commercially available products can be used. An example of a commercially available silica filler is Sunsphere manufactured by AGC Si-Tech Co., Ltd. An example of a commercially available silicone filler is Silicone Powder KMP manufactured by Shin-Etsu Silicone. An example of a commercially available acrylic resin filler is Ganz Pearl manufactured by Aica Kogyo Co., Ltd., and Art Pearl (crosslinked acrylic beads) manufactured by Negami Chemical Industry Co., Ltd. An example of a commercially available urethane resin filler is Art Pearl (crosslinked urethane beads) manufactured by Negami Chemical Industry Co., Ltd. An example of a commercially available polyethylene filler is Flow Beads manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0027] The undercoat layer 2 may contain other additives as necessary, such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

[0028] The undercoat layer 2 can be formed by preparing a coating liquid containing a thermoplastic resin 2R, a first filler 2F and other additives that are added as necessary, and a solvent, applying the coating liquid onto the substrate 1 to form a coating film, and drying the coating film.

[0029] That is, first, a coating liquid containing a first filler 2F, a thermoplastic resin 2R, a solvent, and additives as necessary is prepared. Examples of the solvent include water, alcohol, and organic solvents. The thermoplastic resin may be in the form of an emulsion dispersed in water, alcohol, or the like. Such an emulsion may be prepared by a method of emulsifying a polymer generated by a polymerization reaction of a corresponding monomer, or may be prepared by emulsion polymerization of the corresponding monomer.

[0030] The obtained coating liquid is applied onto the substrate 1. As the coating method, a known method can be used without any particular limitation, and examples thereof include an immersion method (dipping method); and a method using a coater, a printer, a brush, etc. In addition, examples of the types of coaters and printers used in these methods and the coating methods thereof include gravure coaters such as direct gravure method, reverse gravure method, kiss reverse gravure method, and offset gravure method, reverse roll coaters, microgravure coaters, coaters combined with chamber doctor, air knife coaters, dip coaters, bar coaters, comma coaters, die coaters, etc.

[0031] The coating film formed on the substrate 1 is dried and cured by heating, whereby the undercoat layer 2 can be formed on the substrate 1.

[0032] The coating amount of the undercoat layer 2 is 1.0 to 10.0 g / m 2 As will be seen from Examples 8 and 9 described later, the glossiness of the surface of the liquid-repellent layer 3 at a measurement angle of 60 degrees varies depending on the amount of the undercoat layer 2 applied. 2 It is desirable to select an optimum coating amount within this range.

[0033] (liquid repellent layer) The liquid-repellent layer 3 is a layer having liquid repellency, and is formed so as to cover the surface of the undercoat layer 2. Liquid repellency is a concept that includes both water repellency and oil repellency, and specifically, it is a property of repelling liquid or oily materials in a liquid, semi-solid, or gel state. Examples of water-based or oily materials include water, oil, mayonnaise, yogurt, curry, fresh cream, jelly, pudding, syrup, porridge, soup, and other foods, detergents such as hand soap and shampoo, medicines, cosmetics, and chemicals. In the liquid-repellent structure 10, the liquid-repellent layer 3 forms the innermost layer or the outermost layer so that these come into direct contact with each other.

[0034] The liquid-repellent layer 3 contains a binder resin 3R and a filler 3F dispersed in the binder resin 3R. In addition, other additives may be included as necessary within a range that does not impair the liquid-repellent function. In this example, the filler 3F is composed of a scale-like third filler 3Fα and a spherical second filler 3Fβ smaller than the third filler 3Fα. By blending such spherical second filler 3Fβ in the liquid-repellent layer 3, a fine and complex uneven structure can be formed on the surface of the liquid-repellent layer 3. Furthermore, by blending scale-like third filler 3Fα in addition to the spherical second filler 3Fβ, a fine and even more complex uneven structure can be formed on the surface of the liquid-repellent layer 3. In this way, complex unevenness is formed on the surface of the liquid-repellent layer 3, which comes into contact with and supports contents such as oil or a liquid containing oil, thereby further enhancing the liquid repellency.

[0035] In addition, when the liquid repellent layer 3 contains the scaly second filler 3Fα in addition to the spherical third filler 3Fβ, if the weight of the scaly filler 3Fα is small, the undercoat layer 2 is not covered. Therefore, it is necessary to increase the amount of liquid-repellent layer 3 applied, and the coarse unevenness formed by the scaly filler 3Fα will be buried, making it difficult to form a fine and complex uneven structure. To avoid this, and to cover base layer 2 with a small amount of application and form a fine and complex uneven structure on its surface, it is desirable that the weight of scaly filler 3Fα divided by the weight of the spherical filler be within the range of 0.05 to 0.30.

[0036] Next, the binder resin 3R contains at least a fluorine-containing resin. The binder resin 3R may further contain one or both of a thermoplastic resin and a crosslinking agent. When the binder resin 3R contains a crosslinking agent, the binder resin 3R in the liquid-repellent layer 3 may have a crosslinked structure in which the fluorine-containing resin and the thermoplastic resin are crosslinked via the crosslinking agent.

[0037] The fluorine-containing resin is not particularly limited, and resins having a structure such as perfluoroalkyl, perfluoroalkenyl, or perfluoropolyether can be appropriately used. From the viewpoint of further improving the liquid repellency of the liquid repellent layer 3, the fluorine-containing resin preferably contains a fluorine-acrylic copolymer. The fluorine-acrylic copolymer is a copolymer consisting 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.

[0038] The fluorine content in the fluorine-containing resin is, for example, 30 to 60 mass %, and may be 40 to 50 mass %. The fluorine content means the ratio of the mass of fluorine atoms to the total mass of atoms constituting the fluorine-containing resin.

[0039] As the fluorine-containing resin, commercially available fluorine-based paints can be used. Examples of commercially available fluorine-based paints include 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, Unidyne manufactured by Daikin Industries, Ltd., H-3539 series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and Modiper F series manufactured by NOF Corporation.

[0040] From the viewpoint of further improving the liquid repellency against liquids containing surfactants and having high viscosity (e.g., hand soap, body soap, shampoo, and rinse), the fluorine-containing resin may not contain a structural unit derived from pyrrolidone or its derivatives (pyrrolidones). Examples of pyrrolidones include N-vinyl-2-pyrrolidone, N-vinyl-3-methyl-2-pyrrolidone, N-vinyl-5-methyl-2-pyrrolidone, and N-vinyl-3,3-dimethyl-2-pyrrolidone. Examples of fluorine-containing resins that do not contain a structural unit derived from pyrrolidones include Asahiguard AG-E060, AG-E070, and AG-E090 manufactured by Asahi Glass Co., Ltd., and Unidyne TG-8111 manufactured by Daikin Industries, Ltd.

[0041] The thermoplastic resin is not particularly limited, and for example, the resin used as the thermoplastic resin 2R of the underlayer 2 can be used. For example, low-density polyethylene and the like can be used.

[0042] The melting point of the thermoplastic resin is, for example, 50 to 135°C. By having a melting point of 135°C or less, the fluorine-containing resin is easily bled out onto the surface of the liquid-repellent layer 3. By having the fluorine-containing resin bleed out onto the surface, the surface free energy can be reduced, and this allows the surface of the liquid-repellent layer 3 to exhibit excellent liquid repellency. Note that, although there is a method of drying at high temperatures to promote the bleeding out of the fluorine-containing resin, if the melting point of the thermoplastic resin is too high, a correspondingly high temperature is required, which may cause problems such as deformation of the substrate 1. On the other hand, by having a melting point of 50°C or more, a certain degree of crystallinity is ensured, and thus the occurrence of blocking due to softening is suppressed. From this viewpoint, the melting point of the thermoplastic resin is preferably 60 to 120°C. °C is more preferable.

[0043] It is also possible to use modified polyolefins modified with a specific acid as the thermoplastic resin. The modified polyolefins are obtained by graft-modifying polyolefins with unsaturated carboxylic acid derivative components derived from, for example, unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, esters of unsaturated carboxylic acids, etc. In addition, modified polyolefins such as hydroxyl-modified polyolefins and acrylic-modified polyolefins can also be used as the polyolefins. Examples of modified polyolefin resins include Auroren manufactured by Nippon Paper Industries Co., Ltd., Zaixen manufactured by Sumitomo Seika Chemicals Co., Ltd., Unistall manufactured by Mitsui Chemicals, Inc., and Arrowbase manufactured by Unitika Ltd.

[0044] The modified polyolefin is also preferred from the viewpoint that it easily reacts with a crosslinking agent to form a crosslinked structure because a functional group has been introduced therein. Examples of the functional group include a carboxyl group, a hydroxyl group, a (meth)acryloyl group, and an amino group. By using a modified polyolefin having such a functional group together with a crosslinking agent described later, a crosslinked structure consisting of a thermoplastic resin, a fluorine-containing resin, and a crosslinking agent is formed in the liquid-repellent layer 3, and the liquid-repellent layer 3 can be provided with better durability.

[0045] The crosslinking agent is preferably one having a functional group that reacts with the fluorine-containing resin. For example, a crosslinking agent having a functional group such as an aziridine group, an isocyanate group, a carbodiimide group, or an amino group can be used as such a crosslinking agent. For example, commercially available crosslinking 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 Industry Co., Ltd., and Cymel manufactured by Cytec Industries.

[0046] In addition, fluorine-containing resins are generally used as aqueous dispersions in which they are dispersed in water. Therefore, many of the fluorine-containing resins have hydrophilic groups such as hydroxyl groups and amino groups to enhance their affinity with water. By using a crosslinking agent having functional groups that react with the fluorine-containing resin, these functional groups of the fluorine-containing resin react with the functional groups of the crosslinking agent to form a crosslinked structure in the liquid-repellent layer 3. In addition, these functional groups of the fluorine-containing resin are reduced by reacting with the crosslinking agent, so that the functional groups remaining in the liquid-repellent layer 3 are reduced. Therefore, even if the liquid-repellent layer 3 is in contact with a liquid material for a long period of time, the decrease in liquid repellency can be suppressed, and excellent liquid repellency can be maintained for a long period of time. In addition, when the fluorine-containing resin is used as a dispersion in which it is dispersed in a solvent other than water, the fluorine-containing resin may have a structure (e.g., a hydrocarbon chain, etc.) for enhancing the affinity with the solvent used.

[0047] The content of the thermoplastic resin in the binder resin 3R (based on the mass of the binder resin 3R) is, for example, 5 to 90 mass %, and may be 10 to 50 mass %, or 20 to 30 mass %. When the content of the thermoplastic resin in the binder resin 5b is 5 mass % or more, the second filler 3Fα can be sufficiently prevented from falling off from the liquid-repellent layer 3, while when it is 90 mass % or less, the content of the fluorine-containing resin and the crosslinking agent can be sufficiently ensured, and the liquid-repellent layer 3 is likely to exhibit excellent liquid repellency and durability.

[0048] Next, examples of materials constituting the scaly third filler 3Fα include silica, mica, aluminum oxide, talc, titanium oxide, calcium carbonate, barium sulfate, zinc oxide, smectite, and zeolite. Examples of commercially available scaly silica include Sunlovely manufactured by AGC Si-Tech Co., Ltd. Examples of commercially available scaly mica include Repco Mica manufactured by Repco Co., Ltd. Examples of commercially available scaly aluminum oxide include Serashure manufactured by Kawai Lime Industry Co., Ltd. The third filler 3Fα may be one that has not been subjected to hydrophobic treatment or liquid repellency treatment, or may be one that has been subjected to hydrophobic treatment or liquid repellency treatment.

[0049] As shown in the figure, the scale-like third filler 3Fα may form an aggregate inside the liquid-repellent layer 3. These fillers 3Fα and their aggregates form unevenness on the surface of the liquid-repellent layer 3. The aggregates are composed of the third filler 3Fα and the binder resin 3R that covers it.

[0050] The average primary particle size of the scaly third filler 3Fα is preferably 0.1 to 6 μm, and may be 0.1 to 4 μm or 4 to 6 μm. When the average primary particle size of the third filler 3Fα is 0.1 μm or more, aggregates are easily formed, while when the average primary particle size is 6 μm or less, the liquid repellency derived from the complex and fine shape of the third filler 3Fα is fully expressed.

[0051] The weight of the third filler 3Fα contained in the liquid repellent layer 3 is 0.01 to 2.5 g / m 2 It is desirable that the range is 0.01 to 1.5 g / m 2 and may be 0.01 to 0.6 g / m 2 The weight of the third filler 3Fα may be 0.01 g / m 2 If the amount is less than 2.5 g / m, the filler 3Fα is embedded in the binder resin 3R and the complex scale-like uneven shape cannot be imparted, so that liquid repellency cannot be obtained. 2 If the weight of the filler 3Fα is more than 0.01 to 2.5 g / m, the large irregularities formed by the undercoat layer 2 are buried, and liquid repellency cannot be obtained. 2 Within this range, appropriate irregularities can be formed on the surface of the liquid-repellent layer 3, making it possible to obtain liquid repellency.

[0052] Examples of materials constituting the spherical second filler 3Fβ include silica, silicone, acrylic resin, urethane resin, talc, mica, titanium oxide, calcium carbonate, barium sulfate, zinc oxide, smectite, zeolite, and aluminum oxide. For example, the following commercially available products can be used as the filler 3Fβ. That is, an example of the silica filler is AEROSIL50 manufactured by Nippon Aerosil Co., Ltd. SecondThe average primary particle size of the filler 3Fβ is desirably 10 to 100 nm.

[0053] The average particle size of these fillers 2F, 3Fα, and 3Fβ refers to the average value obtained by measuring the major axis and minor axis lengths of any total of 10 fillers within the field of view of SEM or TEM and dividing the sum by 2.

[0054] The method for forming the liquid-repellent layer 3 is the same as the method for forming the underlayer 2. That is, the liquid-repellent layer 3 can be formed by preparing a coating liquid containing a binder resin 3R, a filler 3F and other additives, and a solvent, applying the coating liquid onto the underlayer 2 to form a coating film, and drying the coating film. The solvent used in the coating liquid, the method for applying the coating liquid, and the method for drying the coating film are the same as those for forming the underlayer 2.

[0055] The coating amount of the liquid-repellent layer 3 thus formed is 0.5 to 10.0 g / m 2 The glossiness of the surface of the liquid-repellent layer 3 at a measurement angle of 60 degrees varies depending on the coating amount of the liquid-repellent layer 3, and as will be seen from the examples and comparative examples described later, there is a tendency for the glossiness of the surface of the liquid-repellent layer 3 at a measurement angle of 60 degrees to decrease as the coating amount of the liquid-repellent layer 3 increases. For example, when the composition and coating amount of the undercoat layer 2 are specific values ​​and the composition of the liquid-repellent layer 3 is specific (Examples 1 to 7, Comparative Examples 1 to 3), when the coating amount of the liquid-repellent layer 3 is 1.8 g / m 2 When the coating amount of the liquid-repellent layer 3 is more than 0.5 to 1.8 g / m (Comparative Examples 1 to 3), the gloss level is less than 1.5 GU, and the peelability against viscous liquid containing oil (mayonnaise) is significantly poor. 2 When the gloss level is within this range, the gloss level is within the range of 1.5 to 5.0 GU, and the peelability from viscous liquids containing oil (mayonnaise) is also excellent.

[0056] On the other hand, as can be seen from Examples 8 to 28, when the composition and coating amount of the undercoat layer 2 or the composition of the liquid-repellent layer 3 are different from those of Examples 1 to 7, the coating amount of the liquid-repellent layer 3 is 0.5 to 1.8 g / m 2By setting the coating amount to a range different from the above range, the gloss level can be set within the range of 1.5 to 5.0 GU, and excellent peeling properties can be exhibited against viscous liquid substances (mayonnaise) containing oil.

[0057] As described above, the glossiness and liquid repellency vary depending not only on the amount of liquid repellent layer 3 applied but also on the composition of base layer 2, the amount of application, and the composition of liquid repellent layer 3. Therefore, the glossiness can be controlled by controlling the amount of application of liquid repellent layer 3 depending on the composition of base layer 2, the amount of application, and the composition of liquid repellent layer 3.

[0058] <Packaging material> The packaging material according to this embodiment has a liquid-repellent structure 10 on the side that comes into contact with an article. The packaging material according to this embodiment can be applied to articles containing moisture (e.g., water, beverages, yogurt) and articles containing oil (e.g., curry and fresh cream), and can also be applied to an article that is one type selected from the group consisting of hand soap, body soap, shampoo, and conditioner. Specific embodiments of the packaging material include retort pouches for curry or pasta sauce, containers and lids for yogurt or pudding, containers for toiletries such as hand soap, shampoo, conditioner, or refill pouches for these, tubes for toothpaste or medicines, etc. EXAMPLES

[0059] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0060] In order to fabricate the liquid repellent structures according to the examples and comparative examples, the following materials were prepared.

[0061] First, as the substrate 1, a polyethylene terephthalate film (manufactured by Unitika Ltd., thickness 38 μm) was used.

[0062] The following resins were prepared as thermoplastic resin 2R. All of them were acid-modified polyethylene resins. Abbreviations used in this specification are also shown below.

[0063] Arrowbase SB5230N (manufactured by Unitika Ltd.)...Abbreviation: Resin a In addition, the following three types of fillers were prepared as the first filler 2F. Abbreviations used in this specification are also shown.

[0064] Flow Beads CL-2080 (manufactured by Sumitomo Seika Chemicals Co., Ltd.) - abbreviation: F2-a Sunsphere NP100 (AGC Si-Tech Co., Ltd.) - Abbreviation: F2-b AEROSIL90G (manufactured by Nippon Aerosil Co., Ltd.) - abbreviation: F2-c As the binder resin 3R, a fluorine-containing resin and an acrylic resin were prepared.

[0065] The fluorine-containing resins are as follows. The abbreviations used in this specification are also shown.

[0066] Asahi Guard AG-E060 (manufactured by Asahi Glass Co., Ltd.) - Abbreviation: Fluorine resin a Next, the following filler was prepared as the second spherical filler 3Fβ. The abbreviations used in this specification are also shown below.

[0067] AEROSIL50 (manufactured by Nippon Aerosil Co., Ltd.)...Abbreviation: 3Fβ-a The third scale-like filler 3Fα was Sunlovely manufactured by AGC Si-Tech Co., Ltd. In this specification, it is abbreviated as "3Fα-a".

[0068] As a solvent, 2-propanol was used.

[0069] <Preparation of liquid-repellent structure> (Examples 1 to 28, Comparative Examples 1 to 10) Each component was added to a solvent so that the mass ratio (solid content) of each component in the undercoat layer 2 was as shown in Table 1. This was thoroughly stirred to prepare a coating solution for forming the undercoat layer, which was then applied to a PET film as a substrate by reverse gravure and dried in an oven to form a undercoat layer on the substrate. The coating speed was 30 m / min and the oven temperature was 100°C.

[0070] Next, each component was added to a solvent so that the mass ratio (solid content) of each component in the liquid-repellent layer 3 was as shown in Table 1. This was thoroughly stirred to prepare a coating liquid for forming a liquid-repellent layer, which was then applied onto the underlayer 2 by reverse gravure and dried in an oven to form a liquid-repellent layer on the underlayer 2. The coating speed was 30 m / min and the oven temperature was 100°C.

[0071] [Table 1]

[0072] <Gloss measurement> Each liquid-repellent structure was placed flat on a sheet of black drawing paper with the liquid-repellent layer facing up, and the glossiness was measured at an angle of 60° using a surface gloss meter (Micro-Tri-Gloss) manufactured by BYK.

[0073] <Evaluation of Liquid-Repellent Structure> The liquid repellent structure was evaluated from the following viewpoints.

[0074] (Liquid repellency evaluation) The liquid-repellent structure was placed flat with the liquid-repellent layer side facing up, and 2 μL of the following liquid was dropped onto the liquid-repellent layer using a dropper. The liquid-repellent structure was then stood vertically and left to stand for 30 seconds, and the state of the dropped liquid was visually observed. The liquid repellency was evaluated based on the observation results and the following evaluation criteria. An evaluation result of 2 or more is acceptable for practical use, but 3 or more is preferable.

[0075] [Liquid used] pure water Salad oil: Nissin Salad Oil (Nissin Oillio). Hand soap: Kurashi More Medicated Hand Soap (Japanese Soap).

[0076] [Evaluation Criteria] 1: The liquid remained on the liquid-repellent layer and did not move, or the liquid soaked into the liquid-repellent layer. 2: The liquid flowed down from the liquid-repellent layer, but left a linear mark. 3: The liquid flowed down from the liquid-repellent layer, but left dotted traces. 4: The liquid ran off the liquid-repellent layer, leaving no trace. 5: The droplets became round and rolled off the water-repellent layer, or peeled off.

[0077] (Removability evaluation) The peelability evaluation for viscous foods was carried out by the following method. A polypropylene (PP) film was laid flat, and 2 g of the following viscous food was taken with a medicine spoon and dropped onto the PP film. The liquid-repellent structure was placed so that the surface on the liquid-repellent layer side faced the PP film, and then it was placed on the PP film with a 50 g / 25 cm 2 The liquid-repellent structure was pressed against the viscous food with a load of 1000 g and left to stand for 10 seconds. After that, the liquid-repellent structure was peeled off, and the state of adhesion of the viscous food to the contact surface of the liquid-repellent layer that had been in contact with the viscous food was visually observed. From the observation results, the adhesion was evaluated based on the following evaluation criteria. An evaluation result of 2 or more is practically acceptable, but 3 or more is preferable.

[0078] [Viscous food used] Mayonnaise: Kewpie Mayonnaise (Kewpie Corporation).

[0079] [Evaluation Criteria] 1: Viscous food was found to be attached to 70% or more of the contact surface. 2: Viscous food was found to be attached to 30% or more but less than 70% of the contact surface. 3: Viscous food was found to adhere to 10% or more but less than 30% of the contact surface. 4: Viscous food was found to adhere to less than 10% of the contact surface. 5: No sticky food was found on the contact surface.

[0080] The results are shown in Table 2.

[0081] [Table 2]

[0082] <Consideration> In Examples 1 to 7 and Comparative Examples 1 to 3, the composition and coating amount of the undercoat layer 2 and the composition of the liquid-repellent layer 3 were constant, while the coating amount of the liquid-repellent layer 3 was varied. As can be seen from the results of Examples 1 to 7 and Comparative Examples 1 to 3, the glossiness monotonically decreased as the coating amount of the liquid-repellent layer 3 increased. However, the lower the glossiness, i.e., the greater the coating amount of the liquid-repellent layer 3, the better the liquid repellency to these four types of samples, including the liquid repellency to hand soap and the peelability to mayonnaise. In other words, those with excellent liquid repellency to the four types of samples, pure water, salad oil, hand soap, and mayonnaise, had a coating amount of the liquid-repellent layer 3 of 0.50 to 1.76 g / m 2 Examples 1 to 7 have a gloss level in the range of 1.6 to 5.0 GU, while Comparative Examples 1 to 3, which have a larger amount of liquid-repellent layer 3 applied and higher gloss levels, are inferior in liquid repellency against hand soap and in releasability against mayonnaise.

[0083] Incidentally, as can be seen from Examples 8 to 28, when the composition and coating amount of the underlayer 2 or the composition of the liquid-repellent layer 3 are different from those of Examples 1 to 7, the glossiness may be within the range of 1.5 to 5.0 GU even if the coating amount of the liquid-repellent layer 3 is different from that of Examples 1 to 7. And, regardless of the coating amount of the liquid-repellent layer 3, as long as the glossiness is within the range of 1.5 to 5.0 GU, the liquid repellency is excellent for the above-mentioned four types of samples.

[0084] For example, in Example 17, silica particles having an average primary particle diameter of 10 μm were used as the first filler 2F contained in the undercoat layer 2. In this example, the coating amount of the liquid-repellent layer 3 was 2.05 g / m 2 However, the gloss level is 1.8GU, and the liquid repellency is excellent against the four types of samples mentioned above.

[0085] For example, Comparative Example 7 with a gloss level of 5.3 GU and Comparative Example 8 with a gloss level of 5.5 GU only exhibit poor liquid repellency against hand soap and mayonnaise, whereas Example 18 with a gloss level of 4.8 GU exhibits high liquid repellency against the four types of samples mentioned above.

[0086] From this result, it is understood that the appropriate parameter relating to liquid repellency is not the coating amount of the liquid repellent layer 3, but the glossiness. Also, by referring to Examples 8 to 28 in addition to Examples 1 to 7, it can be understood that if the glossiness is within the range of 1.5 to 5.0 GU, the liquid repellency is excellent against the four types of samples mentioned above, and excellent liquid repellency is also exhibited against viscous liquid substances containing oil (e.g. mayonnaise).

[0087] In addition, Example 10 is an example in which the liquid repellent layer 3 contains the scaly third filler F3α but does not contain the spherical second filler F3β. When comparing Example 10 with Examples 4 and 5, which contain the spherical second filler F3β and have the same coating amount, the gloss of Examples 4 and 5, which contain the spherical second filler F3β, is lower than that of Examples 10 and 2, which do not contain the spherical second filler F3β. 10. It can therefore be seen that by blending the spherical second filler F3β, a fine and complex uneven structure can be formed on the surface of the liquid-repellent layer 3. And, due to such unevenness on the surface of the liquid-repellent layer 3, Examples 4 and 5 exhibit excellent liquid repellency. It can also be seen that the liquid repellency against salad oil and the peelability against mayonnaise are particularly excellent.

[0088] Moreover, Example 12 is an example in which the liquid repellent layer 3 contains the spherical second filler F3β but does not contain the scaly third filler F3α. Comparing this Example 12 with Examples 4 and 5 which contain the scaly third filler F3α and have the same application amount, Example 12 has the same gloss as Examples 4 and 5 which contain the scaly third filler F3α, but the liquid repellency is different. For this reason, it can be said that by blending the scaly third filler F3α in addition to the spherical second filler F3β, it is possible to form a finer and more complicated uneven structure on the surface of the liquid-repellent layer 3. And due to such unevenness on the surface of the liquid-repellent layer 3, Examples 4 and 5 exhibit excellent liquid repellency. The invention as originally claimed is set forth below. [1] A liquid-repellent structure formed by sequentially laminating a base layer and a liquid-repellent layer on a surface to which liquid repellency is to be imparted, The underlayer contains a first filler, the liquid-repellent layer contains a fluorine-containing resin and a second filler, A liquid-repellent structure, characterized in that the gloss of the surface of the liquid-repellent layer at a measurement angle of 60 degrees is within the range of 1.5 to 5.0 GU. [2] Item 2. The liquid repellent structure according to item 1, wherein the second filler is a spherical filler. [3] 3. The liquid-repellent structure according to item 2, wherein the liquid-repellent layer further contains a scale-like filler. [4] 4. The liquid repellent structure according to item 3, wherein a value obtained by dividing the weight of the scaly filler by the weight of the spherical filler is within a range of 0.05 to 0.30. [5] 5. The liquid repellent structure according to any one of items 1 to 4, wherein the first filler is larger than the second filler. [6] 6. A packaging material having the liquid repellent structure according to any one of items 1 to 5 on a side that comes into contact with an article. [Explanation of symbols]

[0089] 10: Liquid repellent structure 1: Base material 2: Base layer 2R: Thermoplastic resin 2F: First filler 3: Liquid repellent layer 3R: Binder resin 3F: Filler 3Fα: Secondary filler 3Fβ: Third filler

Claims

1. A liquid-repellent structure formed by sequentially laminating a base layer and a liquid-repellent layer on a surface to which liquid repellency is to be imparted, The underlayer contains a first filler, the liquid-repellent layer contains a fluorine-containing resin and a second filler, the gloss of the surface of the liquid-repellent layer at a measurement angle of 60 degrees is within a range of 1.5 to 5.0 GU; the second filler is a spherical filler, The liquid repellent layer further contains a scale-like filler, The first filler has an average primary particle size in the range of 5 to 30 μm; The average primary particle size of the second filler is within a range of 10 to 100 nm; The liquid repellent structure is characterized in that the average primary particle diameter of the scale-like filler is within the range of 4 to 6 μm.

2. 2. The liquid repellent structure according to claim 1, wherein a value obtained by dividing the weight of the scaly filler by the weight of the spherical filler is within a range of 0.05 to 0.

30.

3. 3. The liquid repellent structure according to claim 1, wherein the first filler is larger than the second filler.

4. A packaging material having the liquid repellent structure according to any one of claims 1 to 3 on a side that comes into contact with an article.

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