Laminate for water-repellent sheets and its manufacturing method, molded body and its manufacturing method, and water-repellent sheet

Abstract

The present invention provides a laminate that allows for easy modification of the uneven surface shape, enables the stable application of the uneven surface shape to the molded body surface even after thermoforming, and can be manufactured with a small number of steps. [Solution] A laminate for a water-repellent sheet comprising a first resin layer and a second resin layer, wherein the resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other, the first resin layer comprises a first thermoplastic resin and fine particles, the content of the fine particles in the first resin layer is 20 to 70% by mass, and the average particle size of the fine particles is 0.1 μm to 5.0 μm.

Description

[Technical Field]

[0001] The present invention relates to a laminate for water-repellent sheets, a method for manufacturing the same, a molded article, a method for manufacturing the same, and a water-repellent sheet. [Background technology]

[0002] In the food packaging sector, there is a growing demand for environmentally conscious package designs, and efforts are underway to reduce petroleum-derived plastics, partially replace them with paper, and recycle used packaging. While recycling food packaging is being considered, there are challenges such as the lack of established methods for collecting used materials and the increased costs associated with washing away residual contents. Furthermore, in developed countries such as Japan, where the aging population is expected to increase, the need for caregiving foods is growing. These foods aim to provide high nutritional value in small quantities, and products such as high-calorie jellies are offered. However, the contents are often high in protein, and their hydrophobic properties make them difficult to remove from the container. Even if they can be removed, it is difficult to remove the entire contents, resulting in some contents remaining in the container. For the reasons described above, there is a demand for food packaging containers with excellent water repellency and release properties.

[0003] Methods for imparting water repellency and release properties include creating fine irregularities on the surface, and various approaches are being investigated. Examples of methods for creating such shapes include transfer methods, coating methods, and peeling methods. Transfer methods include thermal transfer methods in which a film is heated and pressed using a mold with a fine shape (e.g., Patent Document 1), molten extrusion transfer methods in which molten resin is pressurized and cooled using a cooling roll with a fine shape (e.g., Patent Document 2), and embossing roll transfer methods using a fine-shaped roll. Coating methods include methods in which fine protrusions are created on the coating film by dispersing fine particles in a coating liquid (e.g., Patent Document 3). Peeling methods include methods in which a layer that imparts shape to the substrate is created by co-extrusion or lamination, and then the latter layer is peeled off to impart a fine shape to the substrate surface (e.g., Patent Document 4). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-124135 [Patent Document 2] Japanese Patent Publication No. 2015-25053 [Patent Document 3] International Publication No. 2018 / 003978 [Patent Document 4] Japanese Patent Publication No. 2014-218008 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the transfer method is a batch process, resulting in low productivity, and requires changing the mold when modifying the uneven surface shape. Furthermore, when the sheet obtained by transfer is thermoformed into a container or the like, the heat softens the sheet surface, causing the uneven structure to disappear. Conventional coating methods carry the risk of particles falling off the resulting sheet, and, like the transfer method, suffer from the problem of the uneven surface shape changing during thermoforming. In addition, conventional peeling techniques raise concerns that the shape may change significantly depending on the peeling method.

[0006] The object of the present invention is to provide a laminate that allows for easy modification of the uneven shape, can stably impart an uneven shape to the surface of the molded body even after thermoforming, and can be manufactured with a small number of steps. [Means for solving the problem]

[0007] According to the present invention, the following laminates and the like are provided. 1. comprising a first resin layer and a second resin layer, The resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other. The first resin layer comprises a first thermoplastic resin and fine particles. The content of the fine particles in the first resin layer is 20 to 70% by mass. The average particle size of the aforementioned fine particles is 0.1 μm to 5.0 μm. Laminate for water-repellent sheets. 2. The laminate for water-repellent sheets according to claim 1, wherein the fine particles of the first resin layer are organic fine particles. 3. The laminate for a water-repellent sheet according to claim 1 or 2, wherein the fine particles of the first resin layer are one or more selected from the group consisting of acrylic fine particles, crosslinked styrene fine particles, butadiene rubber fine particles, polyolefin fine particles, crosslinked urethane fine particles, acrylic rubber fine particles, melamine particles, cellulose fine particles, polyethersulfone fine particles, polyphenylene ether fine particles, polylactic acid fine particles, polymethyl methacrylate-styrene copolymer fine particles, polyimide fine particles, polyamideimide fine particles, polyetherimide fine particles, polyarylate fine particles, phenol resin fine particles, and polyamide resin. 4. The laminate for water-repellent sheets according to claim 1, wherein the fine particles of the first resin layer are inorganic fine particles. 5. The laminate for water-repellent sheets according to claim 1 or 2, wherein the fine particles of the first resin layer are one or more selected from the group consisting of silica, talc, calcium carbonate, titanium oxide, alumina, magnesium oxide, molybdenum, tungsten, tungsten carbide, metal boride, metal nitride, metal silicide, copper, zinc oxide, ammonium salt, synthetic zeolite, and barium sulfate. 6. A laminate for a water-repellent sheet according to any one of 1 to 5, wherein the first thermoplastic resin of the first resin layer is one or more selected from the group consisting of polystyrene, polycarbonate, and acrylic resin. 7. A laminate for a water-repellent sheet according to any one of 1 to 7, wherein the second resin layer comprises a thermoplastic resin. 8. A laminate for a water-repellent sheet according to any one of 1 to 8, wherein the second resin layer contains a polyolefin. 9. A laminate for a water-repellent sheet according to any one of 1 to 8, wherein part or all of the interface between the first resin layer and the second resin layer has an uneven shape. 10. The laminate for a water-repellent sheet according to any one of 1 to 9, wherein an interface between the first resin layer and the second resin layer is aseptic. 11. The laminate for a water-repellent sheet according to any one of 1 to 10, which can be peeled at the interface between the first resin layer and the second resin layer. 12. A laminate for a water-repellent sheet comprising a first resin layer and a second resin layer, the resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other, the first resin layer contains a first thermoplastic resin and fine particles, when the first resin layer is peeled off, an uneven shape is formed on a surface of the second resin layer on a side where the first resin layer has been laminated, a normalized intensity obtained by Fourier-transforming an image relating to height information of the uneven shape, integrating a power spectrum with respect to frequency components, and normalizing with an area of an integration region satisfies the following conditions 1 to 3, a laminate for a water-repellent sheet. Condition 1: Normalized intensity for an uneven shape having a height of 0.5 μm: 2.5×10 13 or more Condition 2: Normalized intensity for an uneven shape having a height of 1.0 μm: 2.0×10 13 or more Condition 3: Normalized intensity for an uneven shape having a height of 2.0 μm: 1.5×10 13 or more 13. A water-repellent sheet obtained by peeling the first resin layer from the laminate according to any one of 1 to 12. 14. Having an uneven shape on a surface, a normalized intensity obtained by Fourier-transforming an image relating to height information of the uneven shape, integrating a power spectrum with respect to frequency components, and normalizing with an area of an integration region satisfies the following conditions 1 to 3, a water-repellent sheet. Condition 1: Normalized intensity for an uneven shape having a height of 0.5 μm: 2.5×10 13 or more Condition 2: Normalized intensity for an uneven shape having a height of 1.0 μm: 2.0×10 13 or more Condition 3: Normalized intensity for uneven shape with a height of 2.0 µm: 1.5×10 13 or more 15. The water-repellent sheet according to 13 or 14, which is for food and drink packages, medical supply packages, medical containers, cell culture containers, cell culture bags, building protection, solar panel protection, transportation equipment exteriors, or cosmetic packages. 16. The method for producing a laminate for a water-repellent sheet according to any one of 1 to 12, comprising a step of co-extruding a resin constituting the first resin layer and a resin constituting the second resin layer. 17. A step of molding the laminate for a water-repellent sheet according to any one of 1 to 12, and a step of peeling off the first resin layer from the molded laminate for a water-repellent sheet, a method for producing a molded article. 18. A step of peeling a first resin layer from the laminate for a water-repellent sheet according to any one of 1 to 12 to obtain a sheet, and a step of molding the sheet, a method for producing a molded article. 19. The molded article is a container or a bag body, wherein an uneven shape is formed on the inner surface, the outer surface, or both the inner surface and the outer surface of the container or the bag body, the method for producing a molded article according to 17 or 18. 20. A molded article obtained by the method for producing a molded article according to any one of 17 to 19. 21. The molded article according to 20, which is for food and drink packages, medical supply packages, medical containers, cell culture containers, cell culture bags, building protection, solar panel protection, transportation equipment exteriors, or cosmetic packages. [Advantageous Effects of Invention]

[0008] According to the present invention, there can be provided a laminate in which the uneven shape can be easily changed, the uneven shape can be stably imparted to the surface of a molded article even when thermoforming is performed, and the laminate can be produced by a simple method. [Brief Description of Drawings]

[0009] [Figure 1]This is a schematic cross-sectional view of a laminate according to one aspect of the present invention. [Figure 2] This is a schematic cross-sectional view of a laminate according to one aspect of the present invention. [Figure 3] This is a schematic cross-sectional view showing a state in which the first resin layer has been peeled off from a laminate according to one aspect of the present invention. [Figure 4] This is a schematic diagram of the manufacturing apparatus used to produce the laminates of the examples and comparative examples. [Modes for carrying out the invention]

[0010] The following describes the laminate for water-repellent sheets and its manufacturing method, the molded article and its manufacturing method, and the water-repellent sheet according to the present invention. In this specification, "x~y" represents a numerical range of "x or more, y or less". If there are multiple lower limits such as "x or more" or multiple upper limits such as "y or less" with respect to a single technical matter, these upper and lower limits can be arbitrarily selected and combined.

[0011] [Laminate for the first water-repellent sheet] A laminate for a water-repellent sheet according to one aspect of the present invention (hereinafter also referred to as the "first laminate for a water-repellent sheet" or "first laminate") includes a first resin layer and a second resin layer adjacent to each other. The resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other. The first resin layer comprises a first thermoplastic resin and fine particles, with the fine particle content in the first resin layer being 20 to 70% by mass. The average particle size of the fine particles is 0.1 μm to 5.0 μm.

[0012] The laminate is intended for use in manufacturing a molded article consisting of a second resin layer. By peeling the first resin layer from the laminate at any stage in the manufacturing process of the molded article, a molded article can be obtained in which the surface of the second resin layer to which the first resin layer was laminated is exposed on the inner or outer surface.

[0013] The above-described laminate can be given a fine, uneven surface with excellent water-repellent properties on the surface of the second resin layer by including a specific amount of fine particles of a specific particle size in the first resin layer. Specifically, when the first and second resin layers are manufactured by co-extrusion or the like, the fine particles in the first resin layer appear as convex shapes at the interface between the two layers, and corresponding uneven shapes are formed (transferred) to the surface of the second resin layer. When the first resin layer is peeled off from such a laminate, the surface of the second resin layer with the transferred uneven shape is revealed, and depending on the nature of the unevenness, the surface (resin sheet) exhibits excellent water repellency and release properties.

[0014] Figure 1 shows a schematic cross-sectional view of the first laminate. Laminate 1 includes a first resin layer 10 and a second resin layer 20 provided adjacent to it. Note that the uneven shape caused by the fine particles is not shown in this figure. Also, Figure 1 is simply for explaining the layer structure, and the aspect ratio and film thickness ratio are not necessarily accurate. The same applies to the following drawings. Figure 2 shows an enlarged schematic diagram of the interface between the two layers in the laminate 1. Due to the action of the fine particles 11 contained in the first resin layer 10, countless convex protrusions are formed on the surface of the first resin layer 10, and the corresponding uneven shapes are transferred to the surface of the second resin layer 20. Although fine particles 11 are also present inside the first resin layer 10 other than at the interface, they are not shown in the figure. When the first resin layer 10 is peeled off from the laminate 1, the uneven shape 21 transferred to the second resin layer 20 becomes visible. This shape exhibits excellent water-repellent and release properties, so the peeled second resin layer 20 can be used as a water-repellent sheet or release sheet in various molded articles and the like where these properties are required.

[0015] As described above, the first laminate forms an uneven surface using minute particles, making it possible to achieve extremely fine, microscopic uneven surfaces that are difficult to achieve by physical means such as transfer methods. Furthermore, by appropriately adjusting the size, shape, and amount of the particles, the pitch and size of the uneven surface can be adjusted, allowing the unevenness of the sheet to be easily changed according to the required water-repellent performance. In addition, unlike conventional coating methods, no particles remain on the final molded product in principle, so problems such as particle detachment from containers cannot occur. Moreover, the laminate itself can be manufactured by a normal co-extrusion method, and another advantage is that the uneven surface can be formed by a simple method of peeling off the first resin layer (shape-imparting layer) without using special equipment such as transfer rolls. Moreover, if the first resin layer is thermoformed while still laminated and then peeled off, the uneven surface can be reliably imprinted on the surface of the final molded product. In other words, the first resin layer can function as a protective layer for the resin sheet (second resin layer), and there is no concern that the uneven surface will disappear due to thermoforming, as is the case with transfer methods and coating methods. The following describes the various components of the laminate of the present invention.

[0016] (First resin layer) As described above, the first resin layer is a layer with a specific structure, and its action imparts a fine uneven surface to the surface of the second resin layer. For this reason, the first resin layer is also called the "shape-imparting layer."

[0017] (fine particles) The fine particles used in the first resin layer are not particularly limited as long as their average particle size is between 0.1 μm and 5.0 μm. Their shape is also not particularly limited; examples include spherical, cubic, needle-shaped, irregularly shaped, konpeito-shaped, sunflower-shaped, etc.

[0018] In this invention, the term "fine particles" refers to various particles that can be dispersed in a resin while maintaining their particle state, and does not include rubber-like substances in polymers or the like that have been pre-blended with such substances.

[0019] The average particle size of the fine particles is 0.1 μm to 5.0 μm, and may be, for example, 0.1 μm to 4.0 μm or 0.1 μm to 3.0 μm. With such a size, a textured surface that exhibits high water-repellent performance can be formed on the second resin layer (water-repellent sheet).

[0020] The average particle size of fine particles is measured by the following method. Using photographs taken with an electron microscope (JEOL Corporation, product name: JSM-6010PLUS / LA) of the aggregate of microparticles to be measured, the 10¹⁵ μm size was used. 2 25 particles are randomly selected visually from the region, and the simple average (arithmetic mean) of the particle sizes of these 25 particles is calculated. The particle size is determined using the longest diameter of the particle (the length of the longest part visible in the photograph). For fine particles before mixing with resin, observe and measure them using the method described above, and calculate the average particle size. For fine particles mixed with resin (e.g., pellets, laminates, resin sheets, etc.), observe and measure the fine particles extracted by solvent extraction using the method described above, and calculate the average particle size.

[0021] The fine particles can be organic or inorganic. These can be used individually or in combination of two or more types.

[0022] Examples of organic microparticles include acrylic microparticles, crosslinked styrene microparticles, butadiene rubber microparticles, polyolefin microparticles, crosslinked urethane microparticles, acrylic rubber microparticles, melamine particles, cellulose microparticles, polyethersulfone microparticles, polyphenylene ether microparticles, polylactic acid microparticles, polymethyl methacrylate-styrene copolymer microparticles, polyimide microparticles, polyamideimide microparticles, polyetherimide microparticles, polyarylate microparticles, phenolic resin microparticles, and polyamide resins.

[0023] Examples of inorganic fine particles include silica, talc, calcium carbonate, titanium dioxide, alumina, magnesium oxide, molybdenum, tungsten, tungsten carbide, metal borides, metal nitrides, metal silicides, copper, zinc oxide, ammonium salts, synthetic zeolites, and barium sulfate.

[0024] The content of the fine particles in the first resin layer is 20 to 70% by mass. This content may be, for example, 25% by mass or more, 30% by mass or more, or 65% by mass or less. With such a content, a textured surface that exhibits high water-repellent performance can be formed on the second resin layer (water-repellent sheet).

[0025] (First thermoplastic resin) There are no particular restrictions on the first thermoplastic resin; it can be appropriately selected considering its compatibility and dispersibility with the fine particles mentioned above. Examples include polystyrene, acrylic resin, and polycarbonate. These can be used individually or in combination of two or more.

[0026] The first resin layer may consist of 70% or more by mass of the first thermoplastic resin and fine particles, 80% or more by mass of the first thermoplastic resin and fine particles, 95% or more by mass of the first thermoplastic resin and fine particles, 98% or more by mass of the first thermoplastic resin and fine particles, 99% or more by mass of the first thermoplastic resin and fine particles. The first resin layer may consist substantially of only the first thermoplastic resin and fine particles. In this case, it may contain unavoidable impurities. The first resin layer may consist only of the first thermoplastic resin and fine particles.

[0027] The thickness of the first resin layer is, for example, 5 to 500 μm, preferably 20 to 200 μm.

[0028] (Second resin layer) The second resin layer is a layer intended to be used as a component material of the molded body after the first resin layer has been removed. For this reason, the second resin layer is also called the "base layer." The resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other. Incompatibility means that when the resin constituting the first resin layer and the resin constituting the second resin layer are melted and mixed, they do not form a single phase. This prevents fine particles from migrating to the second resin layer and also makes it easier to separate the two layers.

[0029] The resin constituting the second resin layer is preferably a thermoplastic resin, such as polyolefin (e.g., polypropylene or polyethylene), polyamide, polycarbonate, acrylic resin, or ABS resin (acrylonitrile-butadiene-styrene copolymer resin).

[0030] The second resin layer may contain, as needed, additives such as pigments, antioxidants, stabilizers, and UV absorbers in addition to the thermoplastic resin described above.

[0031] The second resin layer may consist of 70% or more by mass of the above-mentioned thermoplastic resin, 80% or more by mass, 90% or more by mass, 95% or more by mass, 98% or more by mass, 99% or more by mass, 99.5% or more by mass, 99.9% or more by mass, or 100% by mass. The second resin layer may consist substantially of the thermoplastic resin described above. In this case, it may contain unavoidable impurities. The second resin layer may consist solely of the thermoplastic resin described above.

[0032] The thickness of the second resin layer is, for example, 1 to 3000 μm, preferably 5 to 2000 μm, and more preferably 15 to 1000 μm.

[0033] (Laminated structure) As described above, the first laminate contains a first resin layer and a second resin layer adjacent to each other. By peeling off the first resin layer, the fine irregularities of the surface on which the first resin layer was laminated in the second resin layer become apparent, exhibiting water-repellent and release properties. The interface between the first resin layer and the second resin layer is usually sterile.

[0034] The above uneven shape preferably has the following features. An image relating to height information of the uneven shape is subjected to Fourier transform, power spectrum integration is performed on frequency components, and a normalized intensity normalized by an area of an integration region satisfies the following conditions 1 to 3. Condition 1: Normalized intensity for uneven shape with height of 0.5 µm: 2.5×10 13 or more Condition 2: Normalized intensity for uneven shape with height of 1.0 µm: 2.0×10 13 or more Condition 3: Normalized intensity for uneven shape with height of 2.0 µm: 1.5×10 13 or more The normalized intensity for an uneven shape of each height is an index indicating how much an uneven shape having the respective height is present within a specific area. The inventors of the present invention focused on the abundance of uneven shapes having each of the above heights, and found that when all of the above conditions 1 to 3 are satisfied, the uneven surface exhibits excellent water repellent performance. The above normalized intensity is measured by the method described in the Examples.

[0035] The first laminate may be provided with a layer having the same function as the first resin layer on the opposite side of the second resin layer from the first resin layer. As for the configuration thereof, the content described for the first resin layer can be incorporated as it is. By peeling off the front and back layers from such a three-layer laminate, a sheet (second resin layer) with water repellent performance imparted to both surfaces can be obtained.

[0036] In addition to the layers described above, the first laminate may further be laminated with other layers. Examples of other layers include an inorganic filler-containing layer, a highly transparent layer (a layer that enhances the transparency of the laminate), an oxygen barrier layer, an anti-fogging layer, an adhesive layer (a layer that improves the adhesion between the respective layers) and the like. Known layers can be employed as these layers.

[0037] The thickness of the first laminate is, for example, 5 to 5500 µm, preferably 20 to 2100 µm.

[0038] [Second Laminate for Water Repellent Sheet] A laminate for a water-repellent sheet according to another aspect of the present invention (hereinafter also referred to as the "second laminate for a water-repellent sheet" or "second laminate") comprises a first resin layer and a second resin layer adjacent to each other, wherein the resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other. The first resin layer comprises a first thermoplastic resin and fine particles. When the first resin layer is peeled off, an uneven shape is formed on the surface of the second resin layer on the side where the first resin layer was laminated. A Fourier transform is performed on an image relating to the height information of this uneven shape, and the power spectral integral is performed with respect to the frequency components. The normalized intensity, normalized by the area of ​​the integration region, satisfies the following conditions 1 to 3. Condition 1: Normalized strength for uneven surface with a height of 0.5 μm: 2.5 × 10 13 That's all. Condition 2: Normalized strength for uneven surface with a height of 1.0 μm: 2.0 × 10 13 That's all. Condition 3: Normalized strength for uneven surface with a height of 2.0 μm: 1.5 × 10 13 That's all.

[0039] The second laminate is the same as the first laminate described above, except that the average particle size and content of the fine particles are not specified, and conditions 1 to 3 regarding the uneven shape are specified. The matters described for the first laminate can be applied to this laminate.

[0040] [First water-repellent sheet] By peeling off the first resin layer (shape-imparting layer) from the laminate for a water-repellent sheet according to one aspect of the present invention described above (including the first laminate and the second laminate; the same applies hereinafter), a water-repellent sheet (hereinafter also referred to as the "first water-repellent sheet") consisting of the second resin layer (base layer) is obtained. Since this sheet has a specific fine uneven surface shape, it has excellent water-repellent and release properties.

[0041] This sheet can be used in a wide range of applications requiring water repellency and release properties. Examples of such applications include food and beverage packaging, medical product packaging, medical containers, cell culture vessels, cell culture bags, building protection, solar panel protection, transport equipment exteriors, and cosmetic packaging.

[0042] When the above-mentioned sheet is used, for example, as a bag-shaped packaging for food and beverages, the release properties of the contents are improved, making it easier to remove the contents and allowing for complete removal without any residue. In the case of container-shaped packaging, removing the food from the container without damaging its shape allows for a more visually enjoyable dining experience. In addition to food and beverage packaging, the sheet's excellent water-repellent and release properties make it suitable for use in fields where preventing the adhesion of dirt and other contaminants is required. Furthermore, since the surface after peeling off the first resin layer becomes sterile, sterile sheets can be provided for applications such as packaging for medical supplies and cell culture vessels for regenerative medicine.

[0043] [Second water-repellent sheet] A water-repellent sheet according to another aspect of the present invention (hereinafter also referred to as the "second water-repellent sheet") has a surface that satisfies the following conditions 1 to 3. Condition 1: Normalized strength for uneven surface with a height of 0.5 μm: 2.5 × 10 13 That's all. Condition 2: Normalized strength for uneven surface with a height of 1.0 μm: 2.0 × 10 13 That's all. Condition 3: Normalized strength for uneven surface with a height of 2.0 μm: 1.5 × 10 13 That's all. Conditions 1-3 are as described above for the laminated structure.

[0044] [Method for manufacturing laminates for water-repellent sheets] The laminate for a water-repellent sheet according to one aspect of the present invention described above can be manufactured by a manufacturing method that includes a step of co-extruding a resin constituting a first resin layer and a resin constituting a second resin layer. Furthermore, by subsequently peeling off the first resin layer, a water-repellent sheet (resin sheet) with an uneven surface can be manufactured. According to the above manufacturing method, a laminate for water-repellent sheets can be manufactured through a simple process, and an uneven shape can be formed simply by peeling off the first resin layer without using special equipment such as transfer rolls.

[0045] The co-extrusion temperature can be set appropriately according to the type of resin for each layer, but for example, it can be performed in the temperature range of 150 to 450°C. The resin constituting the first resin layer and the resin constituting the second resin layer can be melted separately and co-extruded from a general coat hanger die. Alternatively, it can be co-extruded in a cylindrical shape from a circular die. As for the conditions for peeling the first resin layer, from the viewpoint of uniformity of the uneven surface shape of the second resin layer after peeling, it is preferable to peel the first resin layer from the second resin layer while maintaining a constant peeling speed. Peeling may be done manually or mechanically. Note that the peeling speed and peeling tension do not significantly affect the uniformity of the uneven surface shape.

[0046] [Molded articles and their manufacturing methods] A molded article can be manufactured using a laminate for water-repellent sheets or a water-repellent sheet according to one aspect of the present invention. A method for manufacturing a molded article according to one aspect of the present invention (hereinafter also referred to as the "first method for manufacturing a molded article") includes the steps of molding the above-mentioned laminate and peeling off the first resin layer from the molded laminate. According to this manufacturing method, thermoforming is performed with the first resin layer and the second resin layer in a laminated state, and then the first resin layer is peeled off, thereby reliably imparting a desired uneven shape to the surface of the molded body.

[0047] Examples of molding methods include vacuum forming, vacuum pressure forming, hot plate forming, hot plate pressure forming, high-pressure forming, and press forming. Known methods can be used for these.

[0048] The shape of the molded product is not particularly limited, but examples include container shapes, bag shapes, sheet shapes, film shapes, etc.

[0049] A method for manufacturing a molded article according to another aspect of the present invention (hereinafter also referred to as the "second method for manufacturing a molded article") includes the steps of peeling off the first resin layer from the laminate to obtain a resin sheet, and molding the resin sheet. The method for manufacturing the second molded article is the same as the method for manufacturing the first molded article, except that the first resin layer is peeled off before thermoforming. In this method as well, by adjusting the molding conditions, the relaxation of the uneven shape of the sheet surface can be kept to a minimum.

[0050] Applications for the resulting molded articles include, for example, food and beverage packaging, medical product packaging, medical containers, cell culture vessels, cell culture bags, building protection, solar panel protection, transport equipment exteriors, and cosmetic packaging. [Examples]

[0051] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0052] The materials used in the examples and comparative examples are as follows: • FP-1: Core-shell type butadiene rubber, manufactured by Mitsubishi Chemical Corporation, "C-223A", average particle size = 0.3 μm, copolymer with butadiene rubber as the core component and methyl methacrylate grafted as the shell component. FP-2: Acrylic microparticles (polymethyl methacrylate crosslinked microparticles), manufactured by Nippon Shokubai Co., Ltd. "Epostor MV-1002", average particle size = 1.9 μm • FP-3: Synthetic zeolite microparticles, manufactured by Mizusawa Chemical Industries, Ltd. as "Silton AMT-08L", cubic shape, average particle size = 0.81 μm, amorphous aluminosilicate obtained by chemically modifying synthetic zeolite. • FP-4: Polystyrene-based fine particles, manufactured by Soken Chemical Co., Ltd., "SX-130H", average particle size = 1.3 μm, cross-linked styrene monodisperse particles • PS-1: Impact-resistant polystyrene, manufactured by PS Japan Co., Ltd., "HT478", MFR = 3.0g / 10 min • PS-2: Polystyrene, manufactured by PS Japan Co., Ltd., "SGP10", MFR = 1.9g / 10 min • PP-1: Homopolypropylene, manufactured by Prime Polymer Co., Ltd. "Prime PolyPro F-300SP", MFR = 3.0g / 10 min • PP-2: Homopolypropylene, manufactured by Prime Polymer Co., Ltd., "Prime Polypro E-103WA", MFR = 3.0g / 10 min

[0053] Example 1 (1) Manufacturing of laminates For the first resin layer (shape-imparting layer), PS-1 (first thermoplastic resin, 65% by mass) and FP-1 (fine particles, 35% by mass) were pre-pelletized (average particle size 3.0 mm). In addition, PP-1 was prepared as the resin for the second resin layer (base layer). Using the manufacturing apparatus shown in Figure 4, a laminate consisting of the two layers described above was manufactured by the following method. Specifically, the resins of each layer were co-extruded, the molten resin co-extruded from the T-die 72 was brought into close contact with the cooling roll 76 by an air knife 74, and cooled by the cooling rolls 76 and 78 to manufacture the laminate 71. The manufacturing conditions are as follows: • Extrusion temperature: 230℃ • Laminate retrieval speed: 2.8 m / min • Cooling roll temperature: 80℃ • Thickness of the first resin layer: 20 μm • Thickness of the second resin layer: 200 μm • Overall thickness of the laminate: 220 μm The thickness of each layer and the overall thickness of the laminate were measured using a film thickness gauge (Mitutoyo Corporation "ID-H0530"). The thickness of each layer was measured after separating the first and second resin layers, while the overall thickness of the laminate was measured with the first and second resin layers still laminated together.

[0054] (2) Evaluation of uneven shape The surface shape of the second resin layer, which was obtained by peeling off the first resin layer from the resulting laminate, was evaluated as follows. The results are shown in Table 1. • Structural analysis (normalized strength based on unevenness height) The surface of the second resin layer, which was exposed after peeling off the first resin layer, was observed using a 3D laser microscope (Olympus Corporation's "LEXT4000LS") to obtain images containing height information. The images were acquired in TIF format. The specific observation conditions and measurement methods are as follows. Objective lens: MPLAPONLEXT 100x Optical zoom: 1x Measurement pitch: 0.06 μm Scanning mode: High-precision color Laser intensity: 100% Observation area: 128 μm × 128 μm / sample The acquired TIF format images were subjected to a Fast Fourier Transform (FFT) using image analysis software (imageJ). The specific conversion method is as follows: 1. Images in TIF format were converted to 8-bit monochrome. The Hanning window was applied to the 2.8-bit monochrome image. 3. After applying the Hanning window, the FFT was performed. 4. Power spectral integration (sequential integration over the width of dr in a circular pattern) was performed on the frequency component information obtained by FFT. 5. By normalizing this integral value by the area of ​​the integrated region, the normalized intensity of the structural scale was determined, and a graph was obtained with the normalized integral power spectrum value on the vertical axis and wavelength on the horizontal axis. A larger normalized intensity indicates more irregularities at that scale. 6. From the obtained results, the normalized strengths for each portion at heights of 0.5 μm, 1 μm, and 2 μm were extracted, and the amount of irregularities present at each height was quantified.

[0055] • Surface roughness For images related to height information obtained from 3D laser microscope observations in "Structural Analysis (Normalized Strength of Unevenness Height)," surface roughness was measured with a cutoff value of 25 μm, and the arithmetic mean height (Ra) and the level difference (Sk) of the core were obtained.

[0056] (2) Evaluation The following evaluations were performed on the obtained laminate. The results are shown in Table 1.

[0057] ·Water contact angle The water contact angle was measured using a contact angle meter (CA-XP, manufactured by Kyowa Interface Science Co., Ltd.). Specifically, under conditions of 23°C and 50% RH, approximately 0.9 μm of deionized water was dropped onto the surface of the second resin layer, where the first resin layer had been peeled off, using a syringe. The droplet was then photographed with the contact angle meter's CCD camera, and the contact angle was measured from the shape of the droplet.

[0058] ·Water repellency A water contact angle of 107° or higher was judged to be water-repellent, and was marked with a "○" for water repellency. If the water contact angle was less than 107°, it was not considered to be sufficiently water-repellent, and was marked with a "×" for water repellency.

[0059] Examples 2-5, Comparative Examples 1-3 The laminate was manufactured and evaluated in the same manner as in Example 1, except that the components and compositions listed in Table 1 were used as the materials constituting each layer. In Table 1, "-" indicates that the corresponding material was not used. The results are shown in Table 1.

[0060] [Table 1] [Explanation of Symbols]

[0061] 1. Laminate 10 First resin layer 11 Fine particles 20 Second resin layer 21 Uneven shape 71 Laminate 72 T-die 74 Air Knife 76,78 Cooling Rolls

Claims

1. It comprises a first resin layer and a second resin layer, The resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other. The first resin layer comprises a first thermoplastic resin and fine particles. The content of the fine particles in the first resin layer is 20 to 70% by mass. The average particle size of the aforementioned fine particles is 0.1 μm to 5.0 μm. Laminate for water-repellent sheets.

2. The laminate for a water-repellent sheet according to claim 1, wherein the fine particles of the first resin layer are organic fine particles.

3. The laminate for a water-repellent sheet according to claim 1 or 2, wherein the fine particles of the first resin layer are one or more selected from the group consisting of acrylic fine particles, crosslinked styrene fine particles, butadiene rubber fine particles, polyolefin fine particles, crosslinked urethane fine particles, acrylic rubber fine particles, melamine fine particles, cellulose fine particles, polyethersulfone fine particles, polyphenylene ether fine particles, polylactic acid fine particles, polymethyl methacrylate-styrene copolymer fine particles, polyimide fine particles, polyamideimide fine particles, polyetherimide fine particles, polyarylate fine particles, phenol resin fine particles, and polyamide resin fine particles.

4. The laminate for a water-repellent sheet according to claim 1, wherein the fine particles of the first resin layer are inorganic fine particles.

5. The laminate for a water-repellent sheet according to claim 1 or 4, wherein the fine particles of the first resin layer are one or more fine particles selected from the group consisting of silica, talc, calcium carbonate, titanium oxide, alumina, magnesium oxide, molybdenum, tungsten, tungsten carbide, metal boride, metal nitride, metal silicide, copper, zinc oxide, ammonium salt, synthetic zeolite, and barium sulfate.

6. The laminate for a water-repellent sheet according to any one of claims 1 to 5, wherein the first thermoplastic resin of the first resin layer is one or more selected from the group consisting of polystyrene, polycarbonate, and acrylic resin.

7. The laminate for a water-repellent sheet according to any one of claims 1 to 6, wherein the second resin layer comprises a thermoplastic resin.

8. The laminate for a water-repellent sheet according to any one of claims 1 to 7, wherein the second resin layer contains a polyolefin.

9. The laminate for a water-repellent sheet according to any one of claims 1 to 8, wherein part or all of the interface between the first resin layer and the second resin layer has an uneven shape.

10. The laminate for a water-repellent sheet according to any one of claims 1 to 9, wherein the interface between the first resin layer and the second resin layer is sterile.

11. A laminate for a water-repellent sheet according to any one of claims 1 to 10, which can be peeled off at the interface between the first resin layer and the second resin layer.

12. A laminate for a water-repellent sheet comprising a first resin layer and a second resin layer, The resin constituting the first resin layer and the resin constituting the second resin layer are incompatible with each other. The first resin layer comprises a first thermoplastic resin and fine particles. When the first resin layer is peeled off, an uneven shape is formed on the surface of the second resin layer on the side where the first resin layer was laminated. The image relating to the height information of the aforementioned uneven shape is subjected to a Fourier transform, the power spectral integral is performed with respect to the frequency components, and the normalized intensity normalized by the area of ​​the integration region satisfies the following conditions 1 to 3. Laminate for water-repellent sheets. Condition 1: Normalized strength for uneven surface with a height of 0.5 μm: 2.5 × 10 １３ That's all. Condition 2: Normalized strength for uneven surface with a height of 1.0 μm: 2.0 × 10 １３ That's all. Condition 3: Normalized strength for uneven surface with a height of 2.0 μm: 1.5 × 10 １３ That's all.

13. A water-repellent sheet obtained by peeling off the first resin layer from the laminate according to any one of claims 1 to 12.

14. The surface has an uneven shape, The image relating to the height information of the aforementioned uneven shape is subjected to a Fourier transform, the power spectral integral is performed with respect to the frequency components, and the normalized intensity normalized by the area of ​​the integration region satisfies the following conditions 1 to 3. Water-repellent sheet. Condition 1: Normalized strength for uneven surface with a height of 0.5 μm: 2.5 × 10 １３ That's all. Condition 2: Normalized strength for uneven surface with a height of 1.0 μm: 2.0 × 10 １３ That's all. Condition 3: Normalized strength for uneven surface with a height of 2.0 μm: 1.5 × 10 １３ That's all.

15. The water-repellent sheet according to claim 13 or 14, which is for use in food and beverage packaging, medical product packaging, medical containers, cell culture vessels, cell culture bags, building protection, solar panel protection, transport equipment exteriors, or cosmetic packaging.

16. A method for manufacturing a laminate for a water-repellent sheet according to any one of claims 1 to 12, comprising the step of co-extruding the resin constituting the first resin layer and the resin constituting the second resin layer.

17. A step of forming a laminate for a water-repellent sheet according to any one of claims 1 to 12, and The process includes peeling the first resin layer from the molded laminate for the water-repellent sheet, A method for manufacturing a molded product.

18. A step of obtaining a sheet by peeling off a first resin layer from a laminate for a water-repellent sheet according to any one of claims 1 to 12, and The process includes molding the aforementioned sheet, A method for manufacturing a molded product.

19. The molded body is a container or a bag, The container or bag has an uneven surface, an uneven surface, or both the inner and outer surfaces. A method for manufacturing a molded article according to claim 17 or 18.

20. A molded article obtained by the method for manufacturing a molded article according to any one of claims 17 to 19.

21. The molded body according to claim 20, which is for use in food and beverage packaging, medical product packaging, medical containers, cell culture containers, cell culture bags, building protection, solar panel protection, transport equipment exteriors, or cosmetic packaging.

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