Recording body, method for manufacturing recording body, and recording method

Abstract

Provided is a recording body including a support and a masking layer containing a fusible substance and a binder, the fusible substance being a wax having a branched structure containing an aromatic ring.

Description

Technical Field

[0001] This disclosure relates to a recording medium, a method for manufacturing a recording medium, and a recording method. Background Technology

[0002] In the past, wax-based thermal recording paper was widely used as a thermal recorder. It consists of a layer of colored material and a masking layer containing a molten substance. When the masking layer is heated, the transparency of the masking layer is utilized to form an image.

[0003] Examples of waxes as molten substances include, but are not limited to, low molecular weight polyethylene, carnauba wax (e.g., see Patent Documents 1-5), higher fatty acid esters (e.g., see Patent Document 6), hydrogenated castor oil wax (natural wax, plant-based) (e.g., see Patent Document 7), aliphatic hydrocarbon paraffin wax (natural wax, petroleum-based) (e.g., see Patent Documents 8-9), specific natural waxes, and specific synthetic waxes (e.g., see Patent Document 10). Examples of synthetic waxes include, but are not limited to, polymethylene or polyethylene obtained by polymerization of methane or ethylene (e.g., see Non-Patent Document 1).

[0004] List of cited references

[0005] Patent documents

[0006] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 07-290838

[0007] [Patent Document 2] Japanese Unexamined Patent Application Publication No. 08-073835

[0008] [Patent Document 3] Japanese Unexamined Patent Application Publication No. 08-183256

[0009] [Patent Document 4] Japanese Unexamined Patent Application Publication No. 08-183257

[0010] [Patent Document 5] Japanese Unexamined Patent Application Publication No. 63-141782

[0011] [Patent Document 6] Japanese Unexamined Patent Application Publication No. 2004-345111

[0012] [Patent Document 7] Japanese Patent No. 0252967

[0013] [Patent Document 8] Japanese Patent No. 0467966

[0014] [Patent Document 9] Japanese Patent No. 0488717

[0015] [Patent Document 10] Japanese Patent No. 0664015

[0016] [Non-Patent Literature 1] Toru Tomoeshige, Hiroyasu Fujii, "Synthetic Wax", Polymer, 1977, Vol. 26, September, pp. 637-642 Summary of the Invention

[0017] Technical issues

[0018] The purpose of this invention is to solve various problems in the past and provide a recording device with a high haze change rate and excellent transmittance during recording.

[0019] Solution to the problem

[0020] The recording medium of the present invention, as a means of solving the above-mentioned problems, includes a support and a masking layer containing a molten substance and a binder, wherein the molten substance is a wax having a branched structure containing aromatic rings.

[0021] Effects of the present invention

[0022] According to the present invention, a recording device with a high haze change rate and excellent transmittance during recording can be provided. Attached Figure Description

[0023] [ Figure 1A ]

[0024] Figure 1A This is a schematic diagram illustrating an example of a recording body according to an embodiment of the present invention.

[0025] [ Figure 1B ]

[0026] Figure 1B This is a schematic diagram illustrating another example of a recording body according to an embodiment of the present invention.

[0027] [ Figure 2A ]

[0028] Figure 2A This is a schematic diagram illustrating another example of a recording body according to an embodiment of the present invention.

[0029] [ Figure 2B ]

[0030] Figure 2B This is a schematic diagram illustrating another example of a recording body according to an embodiment of the present invention.

[0031] [ Figure 2C ]

[0032] Figure 2C This is a schematic diagram illustrating another example of a recording body according to an embodiment of the present invention.

[0033] The accompanying drawings are intended to illustrate embodiments of this disclosure and should not be construed as limiting its scope. Unless explicitly stated otherwise, the drawings should not be considered to be drawn to scale. Furthermore, throughout several views, the same or similar reference numerals denote the same or similar parts. Detailed Implementation

[0034] In describing the embodiments shown in the accompanying drawings, specific terminology has been used for clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology chosen, and it should be understood that each particular component includes all technical equivalents that have similar functionality, operate in a similar manner, and achieve similar results.

[0035] Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0036] The prior art image forming methods, including those in Patent Documents 1-10 and Non-Patent Document 1, employ a recording medium in which a coloring layer and a masking layer containing a molten substance are stacked as a thermal recording medium, and the masking layer becomes transparent when heated. In other words, it is an image forming method that utilizes changes in the translucency (haze) and light transmittance of the masking layer during recording (image forming).

[0037] However, in these existing proposals, the reduction in haze of the masking layer during recording (image formation) is small, sometimes resulting in insufficient transmittance. Therefore, when forming an image using a recorder with this masking layer, sufficient sharpness is sometimes not achieved.

[0038] The inventors conducted in-depth research and discovered that by using a wax with a branched structure containing aromatic rings as the molten material contained in the masking layer, excellent transmittance can be achieved. The mechanism by which transmittance is improved is not yet clear, but the following reasons can be speculated.

[0039] Compounds without aromatic ring-containing branched structures readily form straight-chain arrangements between molecules, making them easier to crystallize. On the other hand, compounds with aromatic ring-containing branched structures have less crystallization because the bulky branched structures hinder the intermolecular arrangement of straight-chain structures. That is, it is believed that the increased amorphous portion and reduced particle interfaces suppress light reflection at these interfaces, resulting in higher transmittance.

[0040] The recording medium of the present invention will now be described in detail.

[0041] (Record format)

[0042] The recording medium of the present invention includes a support and a masking layer containing at least a molten substance and an adhesive, and may also have a coloring layer and other layers as needed.

[0043] <Supporting Body>

[0044] There are no particular restrictions on the materials used for the aforementioned support bodies, and appropriate materials can be selected according to the purpose. Examples of materials for the support bodies include, but are not limited to, polyethylene, polypropylene, polyester, polyamide, polystyrene, polyvinyl chloride (PVC), polyethylene terephthalate (PFT), fabrics (nylon, polyester, cotton, etc.), and paper (synthetic paper, washable paper, lightweight coated paper, high-gloss printing paper, art paper, etc.).

[0045] There are no particular restrictions on the shape of the support body, and it can be appropriately selected according to the purpose. Examples of the shape of the support body include, but are not limited to, a membrane, a material formed by stacking the membrane, and a card shape with thickness.

[0046] There are no particular restrictions on the size and structure of the aforementioned support structure; it can be selected appropriately according to the purpose.

[0047] They can be used individually or in combination.

[0048] When the support is in the form of a film, the surface of the film can be subjected to surface treatment. Examples of such surface treatments include matte finishing, corona treatment, and metal vapor deposition.

[0049] In addition, the aforementioned support can also be colored by containing a colorant described later.

[0050] <Shielding Layer>

[0051] The aforementioned masking layer contains at least a molten substance and a binder, and may also contain other components (A) as needed.

[0052] Molten Substances

[0053] The aforementioned molten substance is a wax with a branched structure containing aromatic rings.

[0054] Here, the term "branched structure" in this invention refers to "a structure having substituents other than hydrogen on the side chains of the main chain". The "main chain" refers to the longest straight chain, and the "side chain" refers to a molecular chain that is not the aforementioned main chain.

[0055] Here, "wax" in this invention refers to "an organic substance that is solid or semi-solid at room temperature, melts in a temperature range from room temperature to around 100°C, has low melt viscosity, and has a melting point but no softening point".

[0056] That is, the "wax" described in this invention has a very low melt viscosity compared to ordinary resins, and its shape is easily changed if it is above the melting point.

[0057] Therefore, during non-recording (non-image formation), the substrate can be shielded by light scattering through the gaps in the masking layer. During recording (image formation), the gaps in the masking layer are filled, and by suppressing light scattering, the transmittance can be increased.

[0058] In this invention, substances described as "resin" or "polymer" do not refer to the "wax".

[0059] The waxes containing the branched structure with aromatic rings mentioned above represent waxes containing repeating units as shown in the following general formula (1).

[0060] [Chemical Formula 1]

[0061]

[0062] In the general formula (1), “A” is a bonding group, “B1” and “B2” are terminal groups, “X1” and “X2” are substituents, and “Y” is an aromatic ring group.

[0063] In the above general formula (1), "n" and "m" represent repeating units, where "n" is an integer from 0 to 1000 and "m" is an integer from 1 to 1000.

[0064] In this general formula (1), as the bonding group "A", there are no special restrictions as long as it is a group that connects the main chain and the aromatic ring group. It can be appropriately selected according to the purpose. Examples of bonding group "A" include, but are not limited to, "-(CH2)n-" group (n = 0 to 30), alkoxy group, ester group, ether group, azo group, thioether group, dithioether group, amide group, and urea group.

[0065] In the example of the bonding group "A", from the viewpoint of ease of synthesis, "-(CH2)n-" group (n=0~30), ester group, and ether group are preferred.

[0066] Wax can contain one type of bonding group "A" alone, or it can contain two or more types.

[0067] In this general formula (1), there are no particular restrictions on the terminal groups "B1" and "B2", which can be appropriately selected according to the purpose. Examples of terminal groups "B1" and "B2" include, but are not limited to, alkyl, hydroxyl, carboxyl, sulfonyl, amino, nitro, and phenyl. The terminal groups "B1" and "B2" can be the same or different.

[0068] In this general formula (1), there are no particular restrictions on the substituents "X1" and "X2", which can be appropriately selected according to the purpose. Examples of substituents "X1" and "X2" include, but are not limited to, hydrogen, cyano, acid anhydride, halogen, hydroxyl, carboxyl, sulfonyl, alkyl, alkenyl, alkynyl, amino, nitro, alkoxy, acetyl, formyl, and aldehyde.

[0069] The wax may contain only one of the substituents "X1" and "X2", or it may contain more than two.

[0070] In this general formula (1), the aromatic ring group "Y" is not particularly limited and can be appropriately selected according to the purpose. Examples include phenyl, benzophenyl, pyridyl, furanyl, pyrroleyl, etc. Part of the aromatic ring group "Y" can be replaced by alkyl, hydroxyl, phenyl, halogen, methoxy, sulfonyl, cyano, aldehyde, etc. Among these, phenyl and benzophenyl are preferred from the viewpoint of excellent transmittance and clarity.

[0071] The wax may contain one or more of the aromatic ring group "Y".

[0072] By using a wax with a branched structure containing aromatic rings as the aforementioned molten material, the masking layer containing this molten material can be transformed into a transmissive layer with a high haze variation rate and excellent transmissivity. When this masking layer is laminated together with the coloring layer described later, the colored portions of the coloring layer can be identified in the haze-reduced portions of the masking layer, while the colored portions of the coloring layer are fully masked in the haze-reduced portions of the masking layer, thus creating a contrast difference and enabling the production of images with high sharpness.

[0073] The "haze change rate" in this specification is the ratio of the difference between the haze in the recording before recording (before image formation) and the haze in the recording after recording (after image formation) to the haze in the recording before recording (before image formation). Specifically, it can be calculated using the following formula.

[0074] (Formula)...(Haze in the recording body before recording - Haze in the recording body after recording) / Haze in the recording body before recording

[0075] There are no particular limitations on the rate of change of haze, but it is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.

[0076] There are no particular limitations on the average particle size of the above-mentioned molten material, which can be appropriately selected according to the purpose. It is preferably 1.0 μm or more and 10.0 μm or less, and more preferably 2.0 μm or more and 7.0 μm or less.

[0077] When the average particle size of the molten material is 1.0 μm or more, the problems of reduced shielding and lower haze during non-recording due to smaller gaps between particles can be solved, and therefore it is preferred.

[0078] When the average particle size of the molten material is less than 10.0 μm, the problem of increased unevenness on the surface of the masking layer and the inability to obtain sufficiently low haze during recording can be solved, and therefore it is preferred.

[0079] There are no particular limitations on the methods for determining the average particle size mentioned above; appropriate methods can be selected according to the purpose. Examples include, but are not limited to, determining it from the particle morphology of the molten material observed from a cross-section of the recording body. Cross-sectional observation can be performed by preparing samples using conventional methods and using a transmission electron microscope (TEM).

[0080] The particle size measurements of the molten material observed by TEM are substantially consistent with those of the molten material in the coating solution used to form the masking layer. Therefore, the particle size distribution of the molten material after the masking layer is formed can be set based on the particle size distribution of the molten material in the coating solution. The volume average particle size of the molten material in the coating solution can be measured, for example, using an LA-960 (laser diffusion method, manufactured by Horiba Corporation).

[0081] There are no particular restrictions on the melting point of the above-mentioned molten material, and it can be appropriately selected according to the purpose, preferably above 40°C and below 180°C.

[0082] When the melting point of the molten material is above 40°C, the problem of deteriorated image contrast caused by unnecessary haze reduction in the storage environment of the recording medium can be solved.

[0083] When the melting point of the molten material is below 180°C, the problem of incomplete melting and deterioration of transmissibility during recording due to external stimuli can be solved, and therefore it is preferred.

[0084] As the wax containing the above-mentioned branched structure with aromatic rings, a suitable synthetic wax or a commercially available product can be used.

[0085] Examples of commercially available products containing a wax with a branched structure having an aromatic ring include, but are not limited to, trade names 1160H (manufactured by Mitsui Chemicals) and 1120H (manufactured by Mitsui Chemicals).

[0086] Adhesives

[0087] The adhesive contained in the masking layer is not particularly limited and can be appropriately selected according to the purpose. Examples of such adhesives include ethylene-vinyl acetate copolymer, partially saponified ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-sodium methacrylate copolymer, polyamide, polyester, polyurethane, polyvinyl alcohol, methylcellulose, carboxymethyl cellulose, starch, polyacrylic acid, isobutylene-maleic acid copolymer, styrene-maleic acid copolymer, polyacrylamide, polyvinyl alcohol acetal, polyvinyl chloride, polyvinylidene chloride, isoprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, butyl rubber, and acrylonitrile-butadiene rubber. Among the examples of adhesives, polyester, polyurethane, and polyacrylic acid are preferred from the viewpoint of excellent adhesion to the aforementioned support and image resistance.

[0088] These can be used individually or in combination with two or more.

[0089] There is no particular limitation on the amount of the adhesive added, which can be appropriately set according to the purpose. It is preferably 5 to 100 parts by mass relative to 100 parts by mass of the molten material in the masking layer, and more preferably 5 to 70 parts by mass.

[0090] When the amount of the adhesive added is 5 parts by mass or more relative to 100 parts by mass of the molten material in the above-mentioned masking layer, the problem of poor adhesion to the above-mentioned support, which leads to the peeling of the masking layer, can be solved, and therefore it is preferred.

[0091] When the amount of adhesive added is less than 100 parts by mass relative to 100 parts by mass of the molten material in the masking layer, the problem of reduced ratio of molten material in the masking layer, resulting in increased haze during recording and reduced contrast of the formed image, can be solved, and is therefore preferred.

[0092] Other Ingredients (A)

[0093] As for the other components (A) mentioned above, there are no particular restrictions, and they can be appropriately selected according to the purpose. For example, masking agents, fluxing agents, dispersants, colorants, photothermal conversion agents, etc. can be mentioned.

[0094] -Mascuring Agent-

[0095] There are no particular restrictions on the masking agents mentioned above, and they can be selected appropriately according to the purpose. Examples of masking agents include, but are not limited to, titanium dioxide, zinc oxide, zinc sulfide, silicon oxide, barium sulfate, barium carbonate, and calcium sulfate.

[0096] -Fusing agent-

[0097] There are no particular restrictions on the above-mentioned fluxing agents; they can be selected appropriately according to the purpose. For example, waxes other than the above-mentioned molten substances and monomeric organic hydrophobic substances can be cited.

[0098] There are no particular restrictions on waxes other than the aforementioned molten substances; they can be selected appropriately according to the purpose. Examples include carnauba wax, beeswax, lignite wax, paraffin wax, and synthetic waxes.

[0099] There are no particular limitations on the aforementioned monomeric organic hydrophobic substances; they can be appropriately selected according to the purpose. Examples include biphenyl, o-terphenyl, naphthalene, and anthracene. These can be used alone or in combination.

[0100] -Dispersant-

[0101] There are no particular restrictions on the dispersants mentioned above; they can be selected appropriately according to the purpose. For example, anionic surfactants, cationic surfactants, and nonionic surfactants can be cited.

[0102] These can be used individually or in combination.

[0103] -Coloring agents-

[0104] There are no particular limitations on the above-mentioned colorants, and they can be appropriately selected according to the purpose. Examples of colorants include, but are not limited to, carbon black, azo dyes and pigments, phthalocyanine, quinacridone, anthraquinone, perylene, quinophthalone, aniline black, titanium dioxide, zinc white, and chromium oxide.

[0105] These can be used individually or in combination.

[0106] -Photothermal conversion agent-

[0107] There are no particular limitations on the aforementioned photothermal conversion agents; they can be appropriately selected according to the purpose. Examples of photothermal conversion agents include, but are not limited to, carbon black, graphite, phthalocyanine compounds, anthocyanin compounds, dithiol metal complexes, naphthoquinone compounds, diimine compounds, azo compounds, iron oxide, manganese sulfide, and cesium tungstate.

[0108] There are no particular limitations on the average thickness of the aforementioned masking layer, which can be appropriately selected according to the purpose, but is preferably 1 μm or more and 15.0 μm or less.

[0109] When the average thickness of the masking layer is 1 μm or more, the problem of reduced image contrast caused by the masking layer itself becoming transparent and the increased haze in the non-transmissive part can be solved, and therefore it is preferred.

[0110] When the average thickness of the masking layer is less than 15.0 μm, the problem of insufficient heat transfer during recording and incomplete melting of molten material in the transmission section, resulting in poor transmittance, can be solved, and therefore it is preferred.

[0111] There are no particular limitations on the method for determining the average thickness of the aforementioned masking layer; it can be appropriately selected depending on the purpose. For example, it can be determined by observing the cross-section of the masking layer. Samples can be prepared using conventional methods, and cross-sectional TEM images can be taken using a transmission electron microscope (TEM, JEM-210, manufactured by Nippon Egis Corporation) for observation. Alternatively, the number of samples can be 10, and their average value can be taken as the average thickness.

[0112] <shading layer>

[0113] The aforementioned coloring layer contains colorants and binders, and may also contain other components (B) as needed.

[0114] As for the other component (B), there are no particular limitations, and it can be appropriately selected according to the purpose. For example, dispersants can be mentioned, but it is not limited to this. The colorant can be the same colorant described in the "-Colorant-" section above, the adhesive can be the same adhesive described in the "Adhesive" section above, and the dispersant can be the same dispersant described in the "-Dispersant-" section above, so the description is omitted.

[0115] There are no particular limitations on the method for forming the above-mentioned coloring layer, and it can be appropriately selected according to the purpose. For example, the coloring layer containing the above-mentioned colorant, the above-mentioned adhesive, and the above-mentioned other components (B) as needed can be coated onto the above-mentioned support or the above-mentioned masking layer using a coating liquid, for example, a gravure coating machine, a wire bar coating machine, a roller coating machine, etc., and then dried.

[0116] <Other Layers>

[0117] As for the other layers mentioned above, there are no special restrictions, and they can be selected appropriately according to the purpose. For example, a cover layer can be mentioned.

[0118] Covering Layer

[0119] In order to improve the head-fit of the thermal head, the recording device of the present invention may provide a cover layer on the masking layer. However, when providing the cover layer, it is preferable to provide it in a manner that does not hinder the effective application of external stimuli to the masking layer.

[0120] There are no particular limitations on the aforementioned overlay layer; it can be appropriately selected according to the purpose. For example, overlay layers shown in Japanese Patent Nos. 3657072, 3616845, 7073627, and 7143952 can be cited, but it is not limited to these. From the viewpoint of image protection durability, the overlay layers exemplified in Japanese Patent Nos. 7073627 and 7143952 are preferred.

[0121] There are no particular limitations on the average thickness of the aforementioned covering layer, which can be appropriately selected according to the purpose. From the viewpoint of image protection and thermal conductivity from the thermal head, it is preferably 0.01 μm to 50 μm.

[0122] There are no particular limitations on the method for determining the average thickness of the aforementioned coating layer, and it can be appropriately selected according to the purpose. For example, it can be determined by observing the cross-section of the coating layer. Cross-sectional observation can be performed by preparing samples using conventional methods and taking cross-sectional TEM images using a transmission electron microscope (TEM, JEM-210, manufactured by Nippon Egis Corporation). Furthermore, the number of samples is 10, and their average value is taken as the average thickness.

[0123] Hereinafter, an example of the recording medium of the present invention will be described with reference to the accompanying drawings. However, the uses of the recording medium of the present invention include, but are not limited to, these embodiments.

[0124] Furthermore, in the accompanying drawings, the same reference numerals are used to refer to the same structural parts, and sometimes repeated descriptions are omitted. Additionally, the number, position, shape, etc., of the constituent components described below are not limited to this embodiment; preferred numbers, positions, shapes, etc., used in implementing this invention may be adopted.

[0125] Figure 1A This is a schematic diagram illustrating an example of the recording medium of the present invention. Figures 1B to 2C This is a schematic diagram illustrating another example of the recording medium of the present invention.

[0126] Figure 1A The recording body 10 includes a support body 2 and a masking layer 1 disposed on the support body 2. Figure 1B The recording body 10 includes a masking layer 1 and a support body 2 disposed on the masking layer 1.

[0127] exist Figure 2A In this structure, a coloring layer 3 is provided on one side of the support 2, and a masking layer 1 is provided on the side of the support 2 where the coloring layer 3 is not provided. Figure 2B In the middle, support 2, color layer 3, and masking layer 1 are stacked in sequence. Figure 2C In the middle, a coloring layer 3, a masking layer 1, and a support 2 are stacked in sequence. Alternatively, a cover layer can be provided on the upper surface of the masking layer 1.

[0128] The layer structure of the recording body of the present invention can be any one of the following forms, starting from the bottom layer: (a) masking layer, support body, (b) support body, masking layer, (c) masking layer, support body, coloring layer, (d) masking layer, coloring layer, support body, and (e) support body, masking layer, coloring layer.

[0129] (Method for manufacturing recording media)

[0130] The method for manufacturing a recorder according to the present invention includes a masking layer forming step of coating a masking layer coating liquid onto a substrate, and may also include other steps as needed.

[0131] The “masking layer” is the same as that described in the above (record body) item, so the description is omitted.

[0132] <Shielding Layer Formation Process and Shielding Layer Formation Apparatus>

[0133] The masking layer formation process is a process of applying a masking layer coating liquid onto a substrate. This masking layer formation process can be appropriately performed using a masking layer formation apparatus.

[0134] The shielding layer formation process may also include other processes as needed. These other processes can be carried out by other suitable equipment.

[0135] Here, "base" refers to the <support layer> or <shading layer> described in the above (recording body) items. The <support layer> and <shading layer> described above are the same as those described in the above (recording body) items, so their description is omitted.

[0136] Here, the coating liquid for the masking layer contains the material described in the above-mentioned (recording body) item for the <masking layer>, which means it contains the <molten substance> and the <binder>, and may contain <other components (A)> as needed. The above-mentioned <molten substance>, <binder> and <other components (A)> are the same as those described in the above-mentioned (recording body) item, so their description is omitted.

[0137] There are no particular restrictions on the method for manufacturing the coating liquid for the masking layer. It can be appropriately selected according to the purpose. For example, the following methods can be cited, but it is not limited to them.

[0138] A wax with a branched structure containing aromatic rings, which is a molten substance, is added to ethanol and wet-milled using a disperser (e.g., a six-cylinder disperser, manufactured by IMEX) to prepare a wax dispersion. This wax dispersion, along with the aforementioned binder, and if necessary, with the aforementioned <other components (A)>, is then mixed to prepare a coating liquid for a masking layer.

[0139] This masking layer forming apparatus is an apparatus for applying a masking layer coating liquid onto a substrate. There are no particular limitations on this masking layer forming apparatus, and it can be appropriately selected according to the purpose. For example, coating apparatuses using gravure coating machines, wire bar coating machines, roller coating machines, etc. can be cited, but it is not limited to these.

[0140] Other processes and equipment

[0141] As another process step, a drying process can be cited. As another apparatus, a drying apparatus can be cited. The drying process can be suitably carried out by the drying apparatus.

[0142] (Recording Method)

[0143] The recording method of the present invention is a recording method for recording on a recording body, characterized in that an image is formed by the contrast between the hue of the color in the recording body and the hue of the masking layer in the recording body.

[0144] Specifically, the recording method involves melting the molten material contained in the masking layer through external stimulation, making the masking layer transmissible, and thus forming an image by utilizing the contrast difference between the transmissive and non-transmissive parts.

[0145] Since the recording body is the same as the recording body described above with a coloring layer, the description is omitted.

[0146] There are no particular restrictions on the external stimuli mentioned above; they can be selected appropriately according to the purpose. Examples include heat, light, electromagnetic waves, and pressure.

[0147] When the external stimulus is heat, heating devices such as heating pens and heating heads can be used as examples.

[0148] When the recording medium contains a photothermal conversion agent, a laser can be used to form an image.

[0149] As a specific example of the above-mentioned recording method, one could cite a method in which a layer of white, opaque, molten material is coated on the upper surface of a support or even a coloring layer as a masking layer, and the molten material on the surface is melted by touching a heating element such as a heating pen, thereby causing the coloring layer to develop color. In this case, compared with heat-sensitive color development methods using dyes, it has advantages such as strong lightfastness and resistance to temperature and humidity, and monochromatic color development can also be achieved by changing the color of the coloring layer.

[0150] [Example]

[0151] The following describes embodiments of the present invention, the scope of which includes, but is not limited to, the following embodiments. Unless otherwise specified, "parts" and "%" in the following embodiments and comparative examples refer to "parts by mass" and "% by mass".

[0152] (Example 1)

[0153] <Preparation of Coating Solution for Masking Layer>

[0154] A wax with an aromatic ring-containing branched structure (1160H, manufactured by Mitsui Chemicals Co., Ltd.) was added to ethanol as a melt material to achieve a solid content of 20% by weight. A wax dispersion was prepared by wet milling using a six-cylinder disperser (manufactured by IMEX Co., Ltd.). Laser diffraction particle size distribution measurement device (LA-960, manufactured by Horiba Co., Ltd.) was used to confirm that the wax in the dispersion was milled to a volume average particle size of less than 5 μm. Next, 100 parts of the wax dispersion and 5 parts of an aqueous polyacrylic acid solution (manufactured by BASF Japan, 34% by weight solids) were mixed to obtain a coating solution for a masking layer.

[0155] <Coating with a masking layer using a coating liquid>

[0156] A masking layer coating liquid was applied to one side of a polyester film (Lumirror, manufactured by Toray Industries, Inc.) with an average thickness of 20.0 μm, which served as a support. The film was then dried at 40°C for 30 seconds to form a masking layer with an average thickness of 7.0 μm, thus obtaining a recording device.

[0157] Determination of the average particle size of molten material in the shielding layer

[0158] The average particle size of the molten material in the masking layer was determined by observing the particle morphology of the molten material from a cross-section of the masking layer. Cross-sectional observation involved preparing samples using conventional methods and taking TEM images of the cross-section using a transmission electron microscope (TFM, JEM-210, manufactured by Nippon Electron). The particle sizes of five molten materials in the TEM images were measured, and their average value was taken as the average particle size of the molten material.

[0159] <Measurement of average thickness>

[0160] The average thickness of each layer was determined by observing the cross-section of each layer. Cross-sectional observation involved preparing samples using conventional methods and taking TEM images of the cross-section using a transmission electron microscope (TEM, JEM-210, manufactured by Nippon Electron). Ten samples were used, and their average value was taken as the average thickness.

[0161] (Examples 2-3, Comparative Examples 1-5)

[0162] Except for the changes made to the molten material as shown in Tables 1-2 in the above-described <Preparation of Coating Liquid for Masking Layer>, the recording media of Examples 2-3 and Comparative Examples 1-5 were prepared in the same manner as in Example 1. Furthermore, the oxidized polyethylene wax of Comparative Example 5 was a wax that did not contain aromatic rings but had a branched structure.

[0163] (Examples 4-5)

[0164] Except that the wax used in <Preparation of Coating Liquid for Masking Layer> is changed to the wax obtained by the following Synthesis Examples 1 and 2, the recording media of Examples 4 and 5 are prepared in the same manner as in Example 1.

[0165] (Synthesis Example 1: Synthesis of a wax with an aromatic ring-containing branched structure as described in Example 4)

[0166] 100g of ethylene polymer wax (HP10A, manufactured by Mitsui Chemicals) was heated to 160°C and melted while stirring. Then, while maintaining the temperature, 35g of molten 1-vinyl-4-ethoxybenzene (manufactured by Sigma-Aldrich Japan) and 6g of di-tert-butyl peroxide (manufactured by Sigma-Aldrich Japan) were slowly added dropwise over 2 hours. After the addition was completed, the reaction was allowed to continue for 1 hour, and then the molten wax was directly degassed in a vacuum (10mmHg) for 1 hour to remove volatile components. The wax was then cooled to obtain the wax of Example 4, which has a branched structure containing aromatic rings.

[0167] (Synthesis Example 2: Synthesis of a wax with an aromatic ring-containing branched structure as described in Example 5)

[0168] Except for replacing 1-vinyl-4-ethoxybenzene in Synthesis Example 1 with 4-vinyl-1,1'-biphenyl (Sigma-Aldrich Japan), the wax with a branched structure containing an aromatic ring of Example 5 was obtained by the same method.

[0169] [Table 1]

[0170]

[0171] [Table 2]

[0172]

[0173] [Evaluation of Transmittance]

[0174] The recordings of Examples 1-5 and Comparative Examples 1-5 were heated on a 120°C heating plate from the uncoated side of the masking layer for 30 seconds, and then cooled at room temperature for 30 seconds. The results were then measured using a haze meter (HZ-1, manufactured by Suga Testing Machine Co., Ltd.) and evaluated according to the following criteria. The results are shown in Table 3.

[0175] -Evaluation Criteria-

[0176] Good: Haze value less than 20

[0177] Poor: Haze value greater than or equal to 20

[0178] [Evaluation of vividness]

[0179] <Preparation of coating liquid for coloring layer>

[0180] 100 parts of carbon black (manufactured by Mitsubishi Chemical Corporation) and 150 parts of an aqueous solution of polyacrylic acid (manufactured by BASF JAPAN Corporation, solid content 34% by mass) were added to ethanol to make the solid content 30% by mass. Wet pulverization was performed using a six-cylinder disperser (manufactured by IMEX Corporation), and the carbon black was confirmed to be pulverized to a volume average particle size of less than 0.2 μm using a laser diffraction scattering particle size distribution measuring device (LA-960, manufactured by Horiba Corporation) to obtain a coating solution for the coloring layer.

[0181] <Coating with coating liquid for coloring layer>

[0182] In the recording media of Examples 1-5 and Comparative Examples 1-5, a coloring layer coating liquid was applied to the support surface that had not been coated with a masking layer coating liquid, and dried at 40°C for 30 seconds to form a coloring layer with an average thickness of 1 μm.

[0183] The recordings of Examples 1-5 and Comparative Examples 1-5 were heated on a 120°C heating plate from the uncoated side of the masking layer for 30 seconds, and then cooled at room temperature for 30 seconds. Then, measurements were taken using a reflectance concentration meter (concentration spectrophotometer, manufactured by X-Lite Corporation), and evaluated according to the following evaluation criteria.

[0184] -Evaluation Criteria-

[0185] Good: Reflectance value of 1.20 or above

[0186] Poor: Reflectance concentration value less than 1.20

[0187] [Table 3]

[0188]

[0189] As shown in Table 3, the recording media of Examples 1-5 exhibit higher transmittance and higher sharpness compared to the recording media of Comparative Examples 1-3 and 5. Furthermore, Comparative Example 4, due to its high transmittance before heating, transmits through the substrate. As a result, no change was observed between before and after heating; therefore, the recording media of Comparative Example 4 does not constitute a recording media.

[0190] (Application Example 1)

[0191] <Preparation of Coating Solution for Masking Layer>

[0192] A wax with an aromatic ring-containing branched structure (1160H, manufactured by Mitsui Chemicals) was added to ethanol as a melt material to achieve a solid content of 20% by weight. A wax dispersion was prepared by wet milling using a six-cylinder disperser (IMEX). Laser diffraction particle size distribution measurement device (LA-960, manufactured by Horiba) confirmed that the wax in the dispersion was milled to a volume average particle size of less than 5 μm.

[0193] 100 parts of cesium tungstate (manufactured by Sumitomo Metal Mining Co., Ltd.) and 50 parts of polyacrylic acid (manufactured by BASF JAPAN Co., Ltd.) as a photothermal conversion agent were added to ethanol to make the solid content 20% by weight. A cesium tungstate dispersion was prepared by wet milling using a six-cylinder disperser (manufactured by IMEX Co., Ltd.). The cesium tungstate in the dispersion was confirmed to have been milled to a volume average particle size of less than 0.1 μm using a laser diffraction scattering particle size distribution measuring device (LA-960, manufactured by Horiba Co., Ltd.).

[0194] 100 parts of wax dispersion, 0.5 parts of cesium tungsten oxide dispersion and 6 parts of polyacrylic acid aqueous solution (manufactured by BASF JAPAN, solid content 34% by mass) were mixed to obtain a coating solution for masking layer.

[0195] <Coating with a masking layer using a coating liquid>

[0196] A masking layer coating liquid is applied to one side of a polyester film (Lumirror, manufactured by Toray Industries, Inc.) with an average thickness of 20.0 μm, which serves as a support. The film is then dried at 40°C for 30 seconds to form a masking layer with an average thickness of 7.0 μm, thus obtaining a recording device.

[0197] [Evaluation of Transmittance]

[0198] A semiconductor laser device equipped with a LIMO25-F100-DL808 semiconductor laser (center wavelength: 808nm, manufactured by LIMO Corporation) was used as the semiconductor laser source. The irradiation distance was adjusted to 152mm and the linear velocity to 1,000mm / s, and an image was recorded on the aforementioned recording medium. At this time, a laser pulse velocity of 5mJ / mm² was applied. 2 ~30mJ / mm 2 The recording energy was used for image recording, and the recording energy at which saturation concentration was reached was taken as the saturation recording energy. The transmittance of the recorded image was measured using a haze meter (HZ-1, manufactured by Suga Testing Machine Co., Ltd.), and evaluated according to the following criteria. The results are shown in Table 4.

[0199] -Evaluation Criteria-

[0200] Good: Haze value less than 20

[0201] Poor: Haze level above 20

[0202] [Table 4]

[0203] Transmittance Application Example 1 Good (12.0)

[0204] As can be seen from the results in Table 4, the recorder in Application Example 1 has high transmittance.

[0205] The embodiments of the present invention include the following: <1> ~ <8> item:

[0206] <1>

[0207] A recording medium, comprising:

[0208] Support body; and

[0209] The masking layer contains a molten substance and a binder, wherein the molten substance is a wax with a branched structure containing aromatic rings.

[0210] <2>

[0211] according to <1> The recording medium, wherein the molten material contains repeating units represented by the following general formula (1).

[0212] [Chemical Formula 2]

[0213]

[0214] In general formula (1), “A” is a bonding group, “B1” and “B2” are terminal groups, “X1” and “X2” are substituents, “Y” is an aromatic ring group, “n” is an integer from 0 to 1000, and “m” is an integer from 1 to 1000.

[0215] <3>

[0216] according to <2> The recording body, wherein,

[0217] The aromatic ring group is either phenyl or benzophenyl.

[0218] <4>

[0219] according to <1> ~ <3> The record body described in any one of the following, wherein,

[0220] The average particle size of the molten material is greater than 1.0 μm and less than 10.0 μm.

[0221] <5>

[0222] according to <1> ~ <4> The record body described in any one of the following, wherein,

[0223] The content of the adhesive is 5 parts by mass or more and 100 parts by mass less than 100 parts by mass of the molten material in the masking layer.

[0224] <6>

[0225] according to <1> ~ <5> The recording body described in any one of the following further includes a coloring layer.

[0226] <7>

[0227] A method for manufacturing a recorder includes applying a masking layer coating liquid onto a substrate.

[0228] <8>

[0229] A recording method, comprising:

[0230] Utilizing the contrast between the hue of the color layer and the hue of the mask layer, based on <6> An image is formed on the recording medium.

[0231] according to <1> ~ <6> The recording body described in the document <7> The method for manufacturing the recording medium described herein, and <8> The recording method described herein can solve various problems existing in previous technologies and achieve the purpose of this invention.

[0232] The above embodiments are illustrative and do not limit the invention. Therefore, many additional modifications and variations are possible based on the above teachings. For example, within the scope of the invention, elements and / or features of different illustrative embodiments can be combined with and / or substituted for each other.

[0233] This patent application is based on and claims priority to Japanese Patent Application Nos. 2022-011973 and 2022-205425, filed with the Japan Patent Office on January 28, 2022 and December 22, 2022, respectively, the entire disclosure of each of which is incorporated herein by reference.

[0234] List of reference numerals

[0235] 1: Shielding layer

[0236] 2: Support body

[0237] 3: Coloring layer

[0238] 10: Recording format

Claims

1. A recording medium, comprising: Support body; and The masking layer contains a molten substance and a binder. The molten substance is a wax with a branched structure containing aromatic rings. The wax is an organic substance that is solid or semi-solid at room temperature, melts in a temperature range from room temperature to around 100°C, has low melt viscosity, and has a melting point but no softening point.

2. The recording medium according to claim 1, wherein, The molten material contains repeating units as shown in the following general formula (1), General formula (1) Here, in general formula (1), "A" is a bonding group, "B1" and "B2" are terminal groups, "X1" and "X2" are substituents, "Y" is an aromatic ring group, "n" is an integer from 0 to 1000, and "m" is an integer from 1 to 1000.

3. The recording medium according to claim 2, wherein, The aromatic ring group is either phenyl or benzophenyl.

4. The recording medium according to any one of claims 1 to 3, wherein, The average particle size of the molten material is greater than 1.0 μm and less than 10.0 μm.

5. The recording medium according to any one of claims 1 to 3, wherein, The content of the adhesive is 5 parts by mass or more and 100 parts by mass less than 100 parts by mass of the molten material in the masking layer.

6. The recording medium according to any one of claims 1 to 3, further comprising a coloring layer.

7. A method for manufacturing a recording medium according to any one of claims 1 to 6, comprising: The masking layer coating liquid is applied to the substrate.

8. A recording method, comprising: An image is formed on the recording medium according to claim 6 by utilizing the contrast between the hue of the color layer and the hue of the mask layer.

Images