Recording medium and method for manufacturing a recording medium having a three-dimensional image

Abstract

To provide a recording medium that suppresses a concentration difference in a color image between a foamed part and a non-foamed part, and enables formation of a stereoscopic image in which clear uneven feeling having a sufficient foaming height is expressed, and a method for manufacturing a recorded article having a stereoscopic image using the same.SOLUTION: A recording medium includes a base material, a foam layer which is provided on the base material and contains foam particles foamed by heat and a first binder resin, and a color developing layer provided on the foam layer. The color developing layer contains inorganic particles, and a second binder resin of the same kind as the first binder resin, and an elastic deformation rate of the color developing layer is 60% or more. A method for manufacturing a recorded article includes the steps of: imparting a foam promotion liquid and aqueous ink onto the recording medium; and heating a foam layer, foaming the foamed particles, and forming a stereoscopic image.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a recording medium and a method for manufacturing a recording material having a three-dimensional image. [Background technology]

[0002] Traditionally, three-dimensional image printing technology has been used for printing wallpaper, Braille, and other similar materials. Three-dimensional images are typically formed using methods such as overlaying with UV ink, physical extrusion such as embossing, 3D printing, and thermally expandable plastic foam. Among these, thermally expandable plastic foam is a material that can easily exhibit various functions such as heat shielding, heat insulation, sound insulation, sound absorption, vibration damping, and weight reduction, depending on the foam material and the state of the bubbles formed.

[0003] In the field of wallpaper, a technique is known for forming desired textures using wallpaper materials that have a foamed layer containing a foaming agent with an azo compound such as azodicarbonamide (ADCA) and a resin such as polyvinyl chloride. Furthermore, the technique for forming textures requires that the textures have sufficient height even when monochrome and color images are recorded simultaneously, and that it is possible to form a three-dimensional image with minimal difference in color development between the foamed and unfoamed areas.

[0004] A method has been proposed for forming a three-dimensional image by applying or printing a plasticizer for the shell wall resin of a foamed capsule onto a three-dimensional image-forming layer of a recording material for forming three-dimensional images, which contains foamed capsules, and then heating and foaming the foamed capsules to form a three-dimensional image (Patent Document 1). Another method has been proposed for forming a three-dimensional image by using a recording medium having an ink-receiving layer on the foamed layer, and converting the light energy irradiated after black ink application into thermal energy (Patent Document 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-129116 [Patent Document 2] Japanese Patent Application Publication No. 9-207428 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present inventors investigated the formation of a colored three-dimensional image using the method proposed in Patent Document 1. As a result, it was found that when color ink is applied to a recording medium simultaneously with a foaming accelerator to cause foaming capsules to foam, the color density of the formed foamed areas is significantly lower than that of the unfoamed areas.

[0007] Furthermore, the method proposed in Patent Document 2 uses black ink to convert light energy into thermal energy. For this reason, Patent Document 2 does not mention the use of colored ink. In addition, the present inventors investigated a combination of recording media used in the methods proposed in Patent Documents 1 and 2. As a result, it was found that the color density of the formed foamed portion was significantly lower than the color density of the unfoamed portion.

[0008] Therefore, an object of the present invention is to provide a recording medium capable of forming a three-dimensional image in which the density difference of the color image between the foamed and unfoamed areas is suppressed, and a clear sense of unevenness with sufficient foam height is expressed. Another object of the present invention is to provide a method for manufacturing a recording material having a three-dimensional image in which the density difference of the color image between the foamed and unfoamed areas is suppressed, and a clear sense of unevenness with sufficient foam height is expressed. [Means for solving the problem]

[0009] In other words, according to the present invention, a recording medium comprising a substrate, a foamed layer provided on the substrate containing foamed particles that foam when heated and a first binder resin, and a color-developing layer provided on the foamed layer, wherein the color-developing layer comprises inorganic particles and The firstIt contains two binder resins, The first binder resin and the second binder resin are the same resin, and this same resin is at least one selected from the group consisting of acrylic resin, polycarbonate-modified urethane resin, polyether-modified urethane resin, and polyacrylonitrile resin. A recording medium is provided, characterized in that the elastic deformation rate of the color-developing layer is 60% or more.

[0010] Furthermore, according to the present invention, a recording medium comprising a substrate, a foamed layer provided on the substrate containing foamed particles that foam when heated and a first binder resin, and a color-developing layer provided on the foamed layer, is provided with a foaming accelerator containing a foaming accelerator component that lowers the foaming start temperature of the foamed particles and an aqueous ink, and the step of heating the foamed layer of the recording medium to which the foaming accelerator and the aqueous ink have been applied, to foam the foamed particles and form a three-dimensional image, wherein the color-developing layer contains inorganic particles and The first It contains two binder resins, The first binder resin and the second binder resin are the same resin, and this same resin is at least one selected from the group consisting of acrylic resin, polycarbonate-modified urethane resin, polyether-modified urethane resin, and polyacrylonitrile resin. A method for manufacturing a recording material having a three-dimensional image is provided, characterized in that the elastic deformation rate of the color-developing layer is 60% or more. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a recording medium that can form a three-dimensional image in which the density difference of the color image between the foamed and unfoamed areas is suppressed, and in which a clear sense of unevenness with sufficient foam height is expressed. Furthermore, according to the present invention, it is possible to provide a method for manufacturing a recording material having a three-dimensional image in which the density difference of the color image between the foamed and unfoamed areas is suppressed, and in which a clear sense of unevenness with sufficient foam height is expressed. [Modes for carrying out the invention]

[0012] The present invention will be described in detail below with reference to preferred embodiments. Unless otherwise specified, the physical properties are those obtained at room temperature (25°C).

[0013] <Recording medium> The recording medium of the present invention comprises a substrate, a foamed layer provided on the substrate containing foamed particles that foam upon heat and a first binder resin, and a color-developing layer provided on the foamed layer. The color-developing layer contains inorganic particles and a second binder resin of the same type as the first binder resin. The elastic deformation rate of the color-developing layer is 60% or more.

[0014] The second binder resin in the color-developing layer is of the same type as the first binder resin in the foam layer. "Same type" of binder resin means that, when resins are classified as follows (e.g., acrylic resin, polycarbonate-modified urethane resin, polyether-modified urethane resin, and polyacrylonitrile resin), they belong to the same classification. If the binder resin in the foam layer and the binder resin in the color-developing layer are of different types, heating the foam layer to which the foam-accelerating liquid and water-based ink have been applied will result in different degrees of swelling and shrinkage of the binder resin in the foam layer and the color-developing layer. As a result, cracks are more likely to occur in the color-developing layer after heating, reducing the color development in the foamed areas and increasing the difference in color development between the foamed and unfoamed areas. In contrast, in the recording medium of the present invention, the binder resin in the foam layer and the binder resin in the color-developing layer are of the same type. Therefore, even when the foam layer to which the foam-accelerating liquid and water-based ink have been applied is heated, the degree of swelling and shrinkage of the binder resin in the foam layer and the color-developing layer will be similar. As a result, cracks are less likely to occur in the colored layer after heating, the color development in the foamed areas is less likely to decrease, and the difference in color development between the foamed and unfoamed areas does not widen, thus suppressing the occurrence of concentration differences.

[0015] In addition, the elastic deformation rate of the color-developing layer is 60% or more. When the foamed layer that has foamed during the formation of the three-dimensional image breaks through the adjacent color-developing layer and is exposed on the outermost surface of the recording medium, a layer that is hardly colored appears, resulting in a significant decrease in the color-developing property of the foamed part. That is, by suppressing the exposure of the foamed layer on the outermost surface of the recording medium, the difference in color-developing property between the foamed part and the non-foamed part can be reduced. The color-developing layer with an elastic deformation rate of 60% or more easily follows the shape of the foamed layer. Therefore, it is possible to suppress the exposure of the foamed layer on the outermost surface of the recording medium, and the difference in color-developing property between the foamed part and the non-foamed part can be reduced.

[0016] The elastic deformation rate of the color-developing layer in this specification is a physical property value measured and calculated in accordance with ISO-14577. Specifically, the elastic deformation rate (%) was calculated from the value measured when a indenter was pushed in with a load of 3 mN for 60 seconds from the surface of the color-developing layer to a depth of 1 μm in the thickness direction. As a measuring device for the elastic deformation rate, for example, a microhardness tester (trade name "Pico Indenter HM500, manufactured by Fisher Instruments") can be used.

[0017] (Base material) The base material functions as a support for supporting the foamed layer and the color-developing layer. The type of the base material is not particularly limited. Examples of the base material include paper made of ordinary natural pulp; kenaf paper; plastic film sheets such as polypropylene, polyethylene, and polyester; so-called synthetic paper or non-woven fabric obtained by making synthetic fibers, synthetic pulp, or synthetic resin films look like paper; and the like.

[0018] (Foamed layer) [Expanded particles] As the foamed particles, chemical foaming materials or microcapsule-type foaming materials can be used. Among them, microcapsule-type foaming materials (foamed particles) are preferred. The foamed particles have a shell layer containing a thermoplastic resin and a volatile material encapsulated within this shell layer, and are also called thermally expandable microcapsule-type foaming materials. When heat is applied to these foamed particles, the thermoplastic resin constituting the shell layer softens, and at the same time, the volatile material encapsulated within the shell layer vaporizes and expands in volume. Therefore, the foamed particles expand like a balloon.

[0019] Examples of the thermoplastic resin contained in the shell layer include, for example, polystyrene, styrene-acrylic acid ester copolymer, polyamide resin, polyacrylate, polyvinylidene chloride, polyacrylonitrile, polymethyl methacrylate, vinylidene chloride-acrylonitrile, methacrylate-acrylic acid copolymer, vinylidene chloride-acrylic acid copolymer, vinylidene chloride-acrylic acid ester copolymer, and the like. Among them, the thermoplastic resin is preferably polyacrylonitrile.

[0020] Examples of the volatile material include, for example, low molecular weight hydrocarbons such as ethane, ethylene, propane, propene, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether; chlorofluorocarbons such as CCl3F, CCl2F2, CClF3, CClF2-CClF2; tetraalkylsilanes such as tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyl-n-propylsilane; and the like. Among them, the volatile material is preferably a hydrocarbon having a molecular weight of 120 or less. Also, there is no particular limitation on the lower limit of the molecular weight of the volatile material (hydrocarbon), but for example, it is preferably 50 or more. Among them, from the viewpoint of foamability, the volatile material is preferably isobutane. The content of the foamed particles in the foam layer is preferably 5% by mass or more and 95% by mass or less based on the total mass of the foam layer.

[0021] The foaming start temperature of the foam particles is preferably between 80°C and 100°C. When manufacturing recording media, a coating liquid containing foam particles is usually applied to a substrate, and then the coating liquid is dried to form a foam layer. If the foaming start temperature of the foam particles is below 80°C, the drying temperature of the coating liquid must be set lower than the foaming start temperature, which may slightly reduce the productivity of the recording media. On the other hand, if the foaming start temperature of the foam particles is above 100°C, the heating temperature when forming the three-dimensional image becomes high, which may require excessive thermal energy.

[0022] [First binder resin] The foamed layer contains a first binder resin to enhance adhesion to the substrate and the colored layer. In particular, the first binder resin plays an important role in suppressing the peeling of the foamed layer from the substrate when the foamed particles in the foamed layer foam due to heat. It is preferable to use a water-insoluble resin as the first binder resin. By including a water-insoluble resin in the first binder resin, the first binder resin becomes less likely to dissolve even with water in the foaming accelerator, thus suppressing the decrease in adhesion between the colored layer and the substrate caused by the foaming accelerator. Furthermore, even if an aqueous ink containing water is applied to the recording medium, the decrease in adhesion between the colored layer and the substrate can be suppressed for the same reason. Here, a water-insoluble resin refers to a resin in which 95% or more by mass remains when the resin is immersed in 80°C hot water for 2 hours.

[0023] The first binder resin is preferably at least one water-insoluble resin selected from the group consisting of acrylic resin, polycarbonate-modified urethane resin, polyether-modified urethane resin, and polyacrylonitrile resin. Furthermore, the water-insoluble resin is preferably a non-absorbent resin. The foamed layer may contain both a water-soluble resin and a water-soluble resin, as long as the effects of the present invention are obtained.

[0024] [Composition of the foam layer] The mass ratio of foamed particles to the first binder resin is preferably 5:95 to 50:50. By setting the mass ratio of foamed particles to the first binder resin within the above range, both the foaming properties of the foamed particles and the binding properties of the first binder resin to the substrate can be improved. The foamed layer may further contain components such as pigments, antioxidants, dyes, and surfactants, as long as they do not impair the foaming properties.

[0025] The thickness of the foam layer is preferably between 20 μm and 40 μm. By keeping the thickness of the foam layer within the above range, a sufficient foaming height can be achieved, and the occurrence of cracks during foam layer formation can be suppressed.

[0026] (Coloring layer) [Inorganic particles] The color-developing layer contains inorganic particles such as inorganic pigments. Examples of inorganic pigments include white pigments such as light calcium carbonate, magnesium carbonate, kaolin, barium sulfate, aluminum silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, wet silica sol, dry silica sol, and alumina hydrate. Among these, silica and alumina hydrate are preferred from the viewpoint of ink absorption. The average secondary particle diameter of the inorganic particles is preferably 1 μm or less. By using inorganic particles with an average secondary particle diameter of 1 μm or less, the color development of the image in the unfoamed areas can be further improved. This average secondary particle diameter can be measured by dynamic light scattering.

[0027] [Second binder resin] The second binder resin is of the same type as the first binder resin described above, and the same type as the first binder resin can be used. That is, it is preferable that the first binder resin and the second binder resin are each at least one selected from the group consisting of acrylic resin, polycarbonate-modified urethane resin, polyether-modified urethane resin, and polyacrylonitrile resin.

[0028] [Third binder resin] The coloring layer preferably further contains a third binder resin different from the second binder resin. The third binder resin is preferably a thermoplastic resin with an elongation of 300% or more, as measured according to ATMM D638. By further incorporating such a third binder resin into the coloring layer, the elastic deformation rate of the coloring layer can be increased.

[0029] The third binder resin can be polyvinyl alcohol (PVA), oxidized starch, etherified starch, phosphate-esterified starch, carboxymethylcellulose, or ethylene-vinyl acetate copolymer. Among these, PVA is particularly preferred. As an example of PVA, PVA obtained by hydrolyzing polyvinyl acetate can be cited. The viscosity-average degree of polymerization of PVA is preferably 1,500 to 5,000. The degree of saponification of PVA is preferably 70 to 100. As PVA, modified PVA such as cation-modified PVA, in which the ends are cationically modified, or anion-modified PVA having anionic groups can also be used.

[0030] In the coloring layer, the content (mass%) of the second binder resin is preferably 0.2 to 1.0 times the mass ratio of the content (mass%) of the third binder resin. By using the above mass ratio, the conformability of the coloring layer to the foamed layer is further improved, and the occurrence of cracks in the coloring layer can be further suppressed.

[0031] [Composition of the color-developing layer] The colored layer can be formed, for example, by applying a coating solution for the colored layer containing inorganic particles and a second binder resin to the surface of the foamed layer and then drying it. Here, the dry coating amount of the colored layer is 3 g / m². 2 More than 10g / m 2 The following is preferable: By keeping the dry coating amount of the color-developing layer within the above range, the foam-promoting liquid applied to the color-developing layer can be more effectively penetrated into the foam layer, making it possible to form a three-dimensional image with a more sufficient foamed portion height.

[0032] Preferably, the contact angle between the surface of the color-developing layer and the water 2 seconds after contact with the surface of the color-developing layer is 50° or less. By making the contact angle between the surface of the color-developing layer and the water 50° or less, the foam-promoting liquid applied to the color-developing layer can be more effectively penetrated into the foam layer, making it possible to form a three-dimensional image with a more sufficiently high foamed portion.

[0033] The mass ratio of inorganic particles to binder resin (the sum of the second and third binder resins) is preferably inorganic particles:binder resin = 90:10 to 40:60. By setting the mass ratio of inorganic particles to binder resin within the above range, both the penetration of the foaming accelerator into the foam layer and the binding properties of the inorganic pigment and binder resin can be improved. The coloring layer may further contain components such as pH adjusters, antioxidants, and surfactants, as long as they do not impair the coloring properties and foaming properties.

[0034] (Method of manufacturing recording medium) To manufacture a recording medium, first, a coating liquid for a foamed layer containing foamed particles and a first binder resin is applied to the surface of a substrate to form a coating layer. After drying the formed coating layer, a coating liquid for a color-developing layer containing inorganic particles and a second binder resin is applied to the surface of the dried coating layer (foamed layer) to form a coating layer. Next, the formed coating layer is dried to form a color-developing layer, thereby obtaining a recording medium.

[0035] Conventional air knife coaters, die coaters, blade coaters, gate roll coaters, bar coaters, rod coaters, roll coaters, gravure coaters, curtain coaters, etc., can be used to apply each coating liquid to the surface of the substrate. Methods for drying the coating layer include, for example, blowing hot air onto it. Drying conditions (temperature, airflow, time, etc.) should be set appropriately depending on the type of substrate and the composition of the coating liquid. However, the drying temperature must be lower than the foaming start temperature of the foaming particles used.

[0036] 2 g / m² per side of the base material 2 It is preferable to provide the above foam layer, 20 g / m² 2 It is even more preferable to provide the above foamed layer. 2g / m 2 By providing the above foam layer, the foaming properties can be further improved.

[0037] A back coat layer may be provided on the surface of the substrate opposite to the surface on which the foam layer and color development layer are provided. The back coat layer may be the same layer as the foam layer and color development layer, or it may be a layer other than the foam layer and color development layer. In addition, an adhesive layer containing an adhesive resin such as acrylic resin or an ink-receiving layer for fixing the colorant may be formed.

[0038] <Method of manufacturing a record> By using the aforementioned recording medium, it is possible to manufacture a recording material having a three-dimensional image with a clear sense of relief and sufficient foam height, while suppressing the density difference of the color image between the foamed and unfoamed areas. In other words, the method for manufacturing a recording material having a three-dimensional image according to the present invention comprises the steps of applying a foaming accelerator and aqueous ink to the above-mentioned recording medium, and heating the foamed layer of the recording medium to which the foaming accelerator and aqueous ink have been applied to cause the foamed particles to foam and form a three-dimensional image.

[0039] Examples of heating devices for heating the foamed layer of the recording medium to a desired temperature include dryers, ovens, heating elements, and irons.

[0040] (Foaming accelerator) The foaming accelerator is a liquid composition that contains a foaming-promoting component that lowers the foaming initiation temperature of foaming particles, and preferably further contains water.

[0041] [Foam-promoting ingredients] The foaming accelerator contains foaming-promoting components that lower the foaming initiation temperature of foam particles. When the foaming accelerator containing the foaming-promoting components is applied to the foamed layer of a recording medium by methods such as inkjet ejection or coating, the thermoplastic resin contained in the shell layer of the foam particles can be softened. As a result, it is presumed that the foaming initiation temperature of the foam particles can be shifted to a lower temperature.

[0042] The foam-promoting component can be any component capable of softening the thermoplastic resin contained in the shell layer of the foam particles, and can be appropriately selected and used depending on the type of thermoplastic resin. In particular, the foam-promoting component is preferably a compound that does not have hydroxyl groups. The boiling point of the compound that does not have hydroxyl groups used as a foam-promoting component is higher than the temperature at which the foam layer is heated. Therefore, even when the foam layer is heated, the compound that does not have hydroxyl groups does not easily vaporize and can contribute to the softening of the thermoplastic resin in the shell layer. The content of the compound that does not have hydroxyl groups used as a foam-promoting component is preferably 10% by mass or more and 70% by mass or less, based on the total mass of the foam-promoting liquid.

[0043] The absolute difference (|SP1-SP2|) between the solubility parameter (SP1) of the resin forming the shell layer of the foamed particles (microcapsules) and the solubility parameter (SP2) of the foaming-promoting component is preferably 3.5 or less. By having the absolute difference of the solubility parameters within the above numerical range, the foaming properties in the region of the foamed layer where the foaming-promoting liquid containing the foaming-promoting component is applied can be further improved. Examples of foaming-promoting components include 2-pyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, and N-methyl-2-pyrrolidone.

[0044] The absolute difference (|HSP1-HSP2|) between the Hansen solubility parameter (HSP1) of the resin forming the shell layer of the foam particles (microcapsules) and the solubility parameter (HSP2) of the foam-promoting component is preferably 20 or less. Having the absolute difference of the Hansen solubility parameters within this range allows for further improvement of the foaming properties in the region of the foam layer where the foam-promoting solution containing the foam-promoting component is applied.

[0045] The solubility parameters (SP values) of the thermoplastic resin and foam-promoting component forming the shell layer are both calculated values. Furthermore, the Hansen solubility parameters (HSP values) of the thermoplastic resin and foam-promoting component forming the shell layer are both measured and calculated using dynamic light scattering.

[0046] [Other ingredients] If the foam-promoting component is a liquid at room temperature (25°C), the foam-promoting component itself may be used as the foam-promoting solution. Furthermore, the foam-promoting solution may contain other components besides the foam-promoting component. For example, it is preferable to include additional liquid components such as solvents to improve the discharge stability of the foam-promoting solution. As solvents, water and various water-soluble organic solvents can be used. Deionized water (ion-exchanged water) is preferred as the water. Examples of water-soluble organic solvents include alcohols, glycols, glycol ethers, and nitrogen-containing compounds.

[0047] Other components besides the liquid component include water-soluble organic compounds that are solid at 25°C, such as urea and its derivatives, trimethylolpropane, and trimethylolethane. Furthermore, various additives such as pH adjusters, defoamers, rust inhibitors, preservatives, fungicides, antioxidants, reduction inhibitors, and chelating agents may be included in the foaming accelerator as needed.

[0048] (Water-based ink) Water-based ink (hereinafter also simply referred to as "ink") is a water-based ink containing a colorant. Examples of colorants include pigments and dyes. Among these, the use of pigments as the colorant is preferred.

[0049] Specific examples of pigments include inorganic pigments such as carbon black and titanium dioxide; and organic pigments such as azo pigments, phthalocyanine pigments, perylene pigments, perinone pigments, quinacridone pigments, dioxazine pigments, diketopyrrolopyrrole pigments, quinophthalone pigments, isoindolinone pigments, and imidazolon pigments.

[0050] As for the pigment dispersion method, resin-dispersed pigments using a resin as a dispersant, and self-dispersing pigments in which hydrophilic groups are bonded to the surface of the pigment particles can be used. In addition, resin-bonded pigments in which organic groups containing resin are chemically bonded to the surface of the pigment particles, and microcapsule pigments in which the surface of the pigment particles is coated with resin or the like can be used. Pigments with different dispersion methods may be used in combination. The pigment content (mass%) in the ink is preferably 1.0% by mass or more and 10.0% by mass or less, and more preferably 2.0% by mass or more and 8.0% by mass or less, based on the total mass of the ink.

[0051] The ink is an aqueous ink containing an aqueous medium which is water or a mixed solvent of water and a water-soluble organic solvent. Deionized water (ion-exchanged water) is preferably used as the water. The water content (mass%) in the ink is preferably 50.0% to 95.0% by mass, based on the total mass of the ink. As the water-soluble organic solvent, any solvent usable for inkjet inks, such as alcohols, glycols, (poly)alkylene glycols, nitrogen-containing compounds, and sulfur-containing compounds, can be used. The water-soluble organic solvent content (mass%) in the ink is preferably 3.0% to 50.0% by mass, based on the total mass of the ink. If the water-soluble organic solvent content is outside the above range, the reliability of the inkjet aqueous ink, such as its adhesion resistance, may be slightly reduced.

[0052] In addition to the components mentioned above, the ink may also contain, as necessary, water-soluble organic compounds that are solid at 25°C, such as polyhydric alcohols like trimethylolpropane and trimethylolethane, and urea derivatives like urea and ethylene urea. Furthermore, the ink may contain, as necessary, various additives such as surfactants, pH adjusters, defoamers, rust inhibitors, preservatives, fungicides, antioxidants, reduction inhibitors, and chelating agents. [Examples]

[0053] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited in any way by the following examples unless it exceeds the gist of the invention. Unless otherwise specified, amounts of components expressed in "parts" and "%" are based on mass.

[0054] <Preparing the foaming particles> For the foaming particles, we prepared product name "Expancel 007-40" (manufactured by Nippon Philite). Using a thermomechanical analyzer (TMA) (product name "TMA2940", manufactured by TA instruments), we measured the foaming initiation temperature of the prepared foaming particles using the following procedure. 25 μg of the sample was placed in an aluminum container with a diameter of 7 mm and a depth of 1 mm, and a load of 0.1 N was applied from above. In this state, the container was heated from 60°C to 200°C at a heating rate of 5°C / min, and the displacement in the vertical direction of the measurement terminal was measured. The temperature at which the displacement began was defined as the "foaming initiation temperature". The measured foaming initiation temperature was "91°C".

[0055] <Manufacturing of recording media> (Recording medium 1) [Formation of foam layer] Polypropylene synthetic paper (product name "New Yupo FGS110", manufactured by Yupo Corporation) was prepared as the base material. The first binder resin and foam particles were added to deionized water in a ratio of first binder resin:foam particles = 100:50 (mass ratio), and thoroughly stirred to obtain a coating solution for the foam layer. Acrylic resin (acrylic emulsion, product name "Movinyl 6950", manufactured by Japan Coating Resin) was used as the first binder resin. The obtained coating solution was applied at a rate of 30 g / m². 2 After coating the substrate in this manner, the foamed layer was formed by drying it in a 70°C oven for 5 minutes.

[0056] [Formation of the color-developing layer] Alumina hydrate (product name "DISPERSAL HP30", manufactured by Sasol) was added to deionized water to a concentration of 30%. Furthermore, methanesulfonic acid was added in an amount equal to 0.5% relative to the amount of alumina hydrate, and the mixture was stirred to obtain a colloidal sol. The obtained colloidal sol was diluted with deionized water to obtain inorganic particle dispersion 1, which contained 27% alumina hydrate, an inorganic particle.

[0057] Alumina hydrate (product name "DISPERSAL HP14", manufactured by Sasol) was added to deionized water to a concentration of 30%. Furthermore, methanesulfonic acid was added in an amount equivalent to 1.6% of the alumina hydrate and the mixture was stirred to obtain a colloidal sol. The obtained colloidal sol was diluted with deionized water to obtain inorganic particle dispersion 2, which contained 27% alumina hydrate, an inorganic particle.

[0058] Wet silica (product name "NIPGEL AY-200", manufactured by Tosoh Silica) was added to deionized water to a concentration of 30%. Furthermore, a cation polymer (product name "Unisense FPA-102L", manufactured by Senka) was added in an amount equal to 10% of the amount of wet silica, and the mixture was stirred to obtain a slurry. The obtained slurry was diluted with deionized water to obtain inorganic particle slurry 3, which contained 22% wet silica, an inorganic particle.

[0059] Polyvinyl alcohol (product name "PVA235", manufactured by Kuraray, degree of polymerization 3,500, degree of saponification 88%, elongation 400%) was dissolved in deionized water to obtain an aqueous polyvinyl alcohol solution with a solid content of 8.0%. The second binder resin and the third binder resin were added to the inorganic particle dispersion 1 and mixed to obtain a coating solution for the color development layer. As the second binder resin, the same acrylic resin (acrylic emulsion, product name "Movinyl 6950", manufactured by Japan Coating Resin) as the first binder resin mentioned above was used. As the third binder resin, the above-mentioned polyvinyl alcohol (aqueous polyvinyl alcohol solution with a solid content of 8.0%) was used. In the coating solution for the color development layer, the content of the second binder resin relative to the inorganic particle content was 20%. Also, in the coating solution for the color development layer, the content of the third binder resin relative to the inorganic particle content was 40%.

[0060] The resulting color-developing coating solution has a dry coating rate of 5 g / m². 2 After coating the foam layer in this manner, it was dried in a 70°C oven for 10 minutes to form a color-developing layer, and recording medium 1 was obtained.

[0061] (Recording media 2-24) Recording media 2 to 24 were obtained in the same manner as recording media 1 described above, except that the composition of the foamed layer and the colored layer to be formed, as well as the dry coating amount of the coating liquid for forming the colored layer, were appropriately adjusted as shown in Tables 1-1 to 1-4.

[0062] <Measurement of physical properties of recording media> (contact angle) 1.5 μL of pure water was brought into contact with the surface of the color-developing layer of the recording medium. Then, using a contact angle meter (product name "1100DAT", manufactured by FIBRO), the contact angle (°) between the surface of the color-developing layer and the water was measured 2 seconds after contact. The results are shown in Tables 1-1 to 1-4.

[0063] (elastic deformation rate) The elastic deformation rate (%) of the colored layer was measured and calculated according to a method compliant with ISO-14577. Specifically, using a microhardness tester (product name "Picodenter HM500," manufactured by Fischer Instruments), the elastic deformation rate (%) was calculated from the value measured when an indenter was pressed into the colored layer from the surface to a depth of 1 μm in the thickness direction for 60 seconds with a load of 3 mN. The results are shown in Tables 1-1 to 1-4. Note that the "particle diameter" of inorganic particles listed in Tables 1-1 to 1-4 refers to the average secondary particle diameter.

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[0066] TIFF0007881364000003.tif152170

[0067] TIFF0007881364000004.tif150170

[0068] <Preparation of foaming accelerator> 30 parts dimethyl sulfoxide, 20 parts ethylene glycol, 0.2 parts nonionic surfactant (product name "Acetylenel E100", manufactured by Kawaken Fine Chemicals), and 49.8 parts deionized water were mixed. After thorough stirring, the mixture was pressure filtered through a 1.2 μm pore size filter to obtain a foaming accelerator.

[0069] <Preparation of water-based ink> A mixture was obtained by mixing 10.0 parts of pigment (CI Pigment Red 122), 9.4 parts of a liquid containing styrene-acrylic acid copolymer (acid value 120 mg KOH / g, weight-average molecular weight 8,000), and 80.6 parts of deionized water. The obtained mixture and 200 parts of zirconia beads (0.3 mm diameter) were placed in a batch-type vertical sand mill (manufactured by AIMEX), dispersed for 5 hours while cooling with water, and then centrifuged to remove coarse particles. The mixture was then pressure filtered through a cellulose acetate filter (manufactured by Advantec) with a pore size of 3.0 μm to obtain a pigment dispersion with a pigment content of 10.0% and a resin dispersant (styrene-acrylic acid copolymer) content of 3.0%. 50 parts of the obtained pigment dispersion, 15 parts of glycerin, 10 parts of ethylene glycol, 0.5 parts of a nonionic surfactant (product name "Acetylenel E100", manufactured by Kawaken Fine Chemicals), and 24.5 parts of deionized water were mixed and thoroughly stirred. The mixture was then pressure filtered through a 1.2 μm pore size filter to obtain an aqueous ink.

[0070] <Manufacturing of records> The foaming accelerator and water-based ink were each filled into cartridges and installed in an inkjet recording device (PIXUS PRO-10S, manufactured by Canon). In this embodiment, the recording duty cycle of an image recorded under the condition that eight droplets of approximately 3.8 ng of ink are applied to a unit area of ​​1 / 600 inch x 1 / 600 inch is defined as 100%.

[0071] (Example 1) Using the above inkjet recording device, a foaming accelerator was applied to achieve a recording duty cycle of 80%, and water-based ink was applied to achieve a recording duty cycle of 150%. Fifteen seconds after applying the foaming accelerator, a hot air gun (product name "HL2010E1", manufactured by Sakaguchi Electric Heating Co., Ltd.) was used to heat the foamed layer to a surface temperature of 85°C for 30 seconds. This caused the foam particles in the foamed layer to foam, forming a three-dimensional image and obtaining a recorded material.

[0072] (Examples 2-20, Comparative Examples 1-4) A recorded material was obtained in the same manner as in Example 1 described above, except that the types of recording media shown in Table 2 were used.

[0073] <Rating> (concentration difference) A reflective spectrophotometer (product name "FD-7", manufactured by Konica Minolta, D50 light source, 2° field of view, status A) was used to measure the density of foamed and unfoamed areas in the formed 3D image. The difference between the density of the foamed and unfoamed areas (density difference) was calculated, and the density difference was evaluated according to the evaluation criteria shown below. The results are shown in Table 2. A: The concentration difference was less than 0.05, which was at a level where the difference in concentration could not be perceived. B: The concentration difference was between 0.05 and 0.08, which was at a level where the difference in concentration was not very noticeable. C: The density difference was between 0.08 and less than 0.12, meaning that although a slight difference in density was noticeable, the gradation was not at a level that would cause problems. D: The concentration difference was 0.12 or higher, which was a level where the concentration difference was clearly noticeable.

[0074] (Foam height) A digital micrometer (product name "M-30", manufactured by Sony) was used to measure the height of the foamed portion (foam height) relative to the height of the unfoamed portion on the surface of the obtained recording material. The results are shown in Table 2. A: The foam height was 200 μm or more. B: The foam height was between 150 μm and 200 μm. C: The foam height was between 100 μm and 150 μm.

[0075] TIFF0007881364000005.tif176170

[0076] Furthermore, the disclosure of this embodiment includes the following configuration and manufacturing method. (Configuration 1) A recording medium comprising a base material, a foamed layer provided on the base material containing foamed particles that foam when heated and a first binder resin, and a color-developing layer provided on the foamed layer, The color developing layer contains inorganic particles and a second binder resin of the same type as the first binder resin. A recording medium, wherein an elastic deformation rate of the color developing layer is 60% or more. (Configuration 2) The recording medium according to Configuration 1, wherein the first binder resin and the second binder resin are each at least one selected from the group consisting of an acrylic resin, a polycarbonate-modified urethane resin, a polyether-modified urethane resin, and a polyacrylonitrile resin. (Configuration 3) The color developing layer further contains a third binder resin different from the second binder resin. The recording medium according to Configuration 1 or 2, wherein the third binder resin is a thermoplastic resin having an elongation rate of 300% or more measured in accordance with ATSM D638. (Configuration 4) The recording medium according to Configuration 3, wherein in the color developing layer, a content (% by mass) of the second binder resin is 0.2 times or more and 1.0 times or less in terms of a mass ratio with respect to a content (% by mass) of the third binder resin. (Configuration 5) The recording medium according to any one of Configurations 1 to 4, wherein an average secondary particle diameter of the inorganic particles is 1 μm or less. (Configuration 6) The recording medium according to any one of Configurations 1 to 5, wherein a dry coating amount of the color developing layer is 3 g / m 2 or more and 10 g / m 2 or less. (Configuration 7) The recording medium according to any one of Configurations 1 to 6, wherein a contact angle between the surface of the color developing layer and water after 2 seconds from bringing water into contact with the surface of the color developing layer is 50° or less. (Configuration 8) The recording medium according to any one of Configurations 1 to 7, wherein a thickness of the foaming layer is 20 μm or more and 40 μm or less. (Manufacturing Method 1) A recording medium including a substrate, a foaming layer provided on the substrate and containing foaming particles that foam by heat and a first binder resin, and a color developing layer provided on the foaming layer, the steps of applying a foaming promoting liquid containing a foaming promoting component for reducing a foaming start temperature of the foaming particles and an aqueous ink. The process includes heating the foam layer of the recording medium to which the foam-promoting liquid and the aqueous ink have been applied, and causing the foam particles to foam up to form a three-dimensional image. The color-developing layer contains inorganic particles and a second binder resin of the same type as the first binder resin. A method for manufacturing a recording material having a three-dimensional image, characterized in that the elastic deformation rate of the color-developing layer is 60% or more.

Claims

1. A recording medium comprising a base material, a foamed layer provided on the base material containing foamed particles that foam upon heat and a first binder resin, and a color-developing layer provided on the foamed layer, The color-developing layer contains inorganic particles and a second binder resin. The first binder resin and the second binder resin are the same resin, and this same resin is at least one selected from the group consisting of acrylic resin, polycarbonate-modified urethane resin, polyether-modified urethane resin, and polyacrylonitrile resin. A recording medium characterized in that the elastic deformation rate of the color-developing layer is 60% or more.

2. The color-developing layer further contains a third binder resin different from the second binder resin, The recording medium according to claim 1, wherein the third binder resin is a thermoplastic resin with an elongation of 300% or more as measured in accordance with ATMM D638.

3. The recording medium according to claim 2, wherein the content (mass%) of the second binder resin in the coloring layer is 0.2 times or more and 1.0 times or less in mass ratio to the content (mass%) of the third binder resin.

4. The recording medium according to claim 1 or 2, wherein the average secondary particle diameter of the inorganic particles is 1 μm or less.

5. The dry coating amount of the aforementioned color-developing layer is 3 g / m². ２ 10g / m or more ２ The recording medium according to claim 1 or 2, wherein the recording medium is as follows:

6. The recording medium according to claim 1 or 2, wherein the contact angle between the surface of the color-developing layer and the water two seconds after water is brought into contact with the surface of the color-developing layer.

7. The recording medium according to claim 1 or 2, wherein the thickness of the foamed layer is 20 μm or more and 40 μm or less.

8. A recording medium comprising a base material, a foamed layer provided on the base material containing foamed particles that foam upon heat and a first binder resin, and a color-developing layer provided on the foamed layer, is provided with a foaming accelerator containing a foaming accelerator that lowers the foaming start temperature of the foamed particles and an aqueous ink. The process includes heating the foam layer of the recording medium to which the foam-promoting liquid and the aqueous ink have been applied, and causing the foam particles to foam up to form a three-dimensional image. The color-developing layer contains inorganic particles and a second binder resin. The first binder resin and the second binder resin are the same resin, and this same resin is at least one selected from the group consisting of acrylic resin, polycarbonate-modified urethane resin, polyether-modified urethane resin, and polyacrylonitrile resin. A method for manufacturing a recording material having a three-dimensional image, characterized in that the elastic deformation rate of the color-developing layer is 60% or more.

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