Laser marking information recording medium

Abstract

An object of the present invention is to provide an information recording medium that is equipped with a substrate having an uneven shape on at least one surface thereof and yet is capable of printing with good print quality. The laser marking information recording medium 1 of the present invention is an information recording medium in which a first substrate 2, a color-developing layer 4, and a second substrate 7 are laminated in this order. The first substrate 2 and / or the second substrate 7 are layers that transmit ultraviolet light. The second substrate 7 has an uneven shape on at least one surface.

Description

Technical Field

[0001] The present invention relates to an information recording medium for laser marking.

Background Art

[0002] Various methods have been proposed as methods for printing on an information recording medium and recording information. Among them, printing by a thermal printer is a typical printing method, and a thermal method and a thermal transfer method are known.

[0003] In the above thermal method, the thermal recording medium itself develops color and functions as an information recording medium. Specifically, the thermal head of a thermal printer is pressed against the thermal recording medium, and when the thermal recording medium is heated, color development occurs and printing is performed. The above thermal recording medium is used in a wide range of applications not only as a recording medium for facsimiles, automatic ticket vending machines, and scientific measuring instruments, but also as a thermal recording label for a POS system in a retail store or the like, receipt paper, and the like. As the above thermal recording medium, those having a laminated structure of [base material / thermal recording layer / protective layer] have been conventionally proposed, and recently, those having a novel laminated structure of [transparent film / thermal recording layer / adhesive layer] have also been proposed (see, for example, Patent Document 1). Since these thermal recording media are all manufactured by coating a coating liquid for forming a thermal recording layer or the like on a base material, in order to stably manufacture, it is necessary to ensure coatability using a base material having at least one smooth surface.

[0004] In the above thermal transfer method, printing is performed by transferring ink to an object to be printed such as a packaging film, so the object to be printed functions as an information recording medium. Specifically, the thermal head of a thermal printer is pressed against the object to be printed via an ink ribbon, and printing is performed by transferring the ink ribbon melted by heat to the object to be printed. Such a printing method is widely used in scenes such as printing lot numbers on product packaging films. In the above thermal transfer method, since it is necessary to uniformly transfer the ink ribbon to the surface of the object to be printed, at least the surface of the object to be printed on the thermal head side needs to be smooth.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Here, in any printing method using a thermal printer, printing is performed by pressing a thermal head against a thermal recording medium or the like, so it is necessary for the thermal head to come into uniform contact with the printing surface. Generally, the thermal recording medium or the object to be printed by a thermal printer often has a small thickness and is a thin sheet-like laminate. For this reason, if printing is performed on a sheet-like laminate having an uneven shape on one end face and a smooth other end face using a thermal printer, even if the thermal head is applied to the smooth end face, due to the influence of the uneven shape of the other end face, the way the thermal head hits becomes non-uniform, and there is a problem that the printing quality deteriorates, such as a part of the printing being missing. Therefore, in order to print on a thin sheet-like laminate with good printing quality, it is generally required that both sides of the laminate are smooth so that the thermal head hits uniformly. Against this background, usually, a base material for a thermal recording medium or an object to be printed having smooth both sides is used.

[0007] By the way, since the uses of information recording media are extensive, creating new demand is expected by providing on the market an information recording medium that can give a sense of beauty to viewers. As such an information recording medium that can give a sense of beauty, an information recording medium having on one end face a base material such as Japanese paper or a matte film, that is, a base material excellent in design properties such as texture, translucency, and fluffiness, can be considered.

[0008] However, since base materials such as Japanese paper and matte films have uneven surfaces, it is difficult to apply the thermal head evenly in the printing method using the thermal printer, and there has been a problem that it is difficult to achieve good printing quality. Also, in printing methods other than thermal printers, such problems have not been fully recognized yet, so specific studies have not been sufficiently carried out. For this reason, there has been a problem that an information recording medium having a base material with an uneven shape on at least one surface and capable of printing with good printing quality has not been specifically provided yet.

[0009] The present invention has been conceived under such circumstances, and its object is to provide an information recording medium having a base material with an uneven shape on at least one surface and capable of printing with good printing quality.

Means for Solving the Problems

[0010] As a result of intensive studies to achieve the above object, the present inventors have found that according to a specific information recording medium in which a first base material, a color developing layer, and a second base material are laminated in this order, even if the second base material has an uneven shape on at least one surface, it can be printed with good printing quality by laser marking. The present invention has been completed based on these findings.

[0011] That is, the present invention is an information recording medium in which a first base material, a color developing layer, and a second base material are laminated in this order, the above first base material and / or the above second base material is a layer that transmits ultraviolet rays, and the above second base material provides an information recording medium for laser marking having an uneven shape on at least one surface.

[0012] The above second base material is preferably at least one selected from the group consisting of Japanese paper, non-woven fabric, and a resin film having an uneven shape on at least one surface.

[0013] The surface of the second substrate having the concavo-convex shape is preferably provided on the side opposite to the color-developing layer.

[0014] The opacity of the second substrate is preferably 51% or less.

[0015] The color-developing layer preferably contains a leuco dye and a developer.

[0016] The developer preferably contains a non-phenolic developer.

[0017] The non-phenolic developer preferably contains at least a compound represented by the following formula (1) and / or a compound represented by the following formula (2).

Chemical formula

Chemical formula

[0018] The non-phenolic developer more preferably contains at least the compound represented by the above formula (1).

[0019] It is preferable that an intermediate layer is further provided between the color-developing layer and the second substrate.

[0020] The intermediate layer preferably contains a resin having a water-soluble portion and / or a crosslinking agent.

[0021] It is preferable that the color-developing part in the color-developing layer is visible through the second base material.

[0022] The first base material is preferably a layer that transmits ultraviolet rays.

[0023] It is preferable that the information recording body for laser marking can develop color by irradiation with ultraviolet laser light.

Effect of the Invention

[0024] According to the present invention, it is possible to provide an information recording body for laser marking that has a base material with an uneven shape on at least one surface and can be printed with good printing quality.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0026] [Information Recording Body for Laser Marking] The information recording medium for laser marking of the present invention has a laminated structure in which at least a first base material, a color developing layer, and a second base material are laminated in this order. The above-mentioned first base material and / or the above-mentioned second base material is a layer that transmits ultraviolet rays. Further, the above-mentioned second base material has an uneven shape on at least one surface. The information recording medium for laser marking of the present invention may have the surface with the uneven shape of the above-mentioned second base material on the side opposite to the above-mentioned color developing layer, or may have it on the side of the above-mentioned color developing layer. From the viewpoint of further improving the design property, it is preferable that the information recording medium for laser marking of the present invention has the surface with the uneven shape of the above-mentioned second base material on the side opposite to the above-mentioned color developing layer. Also, it is preferable that the information recording medium for laser marking of the present invention has the surface with the uneven shape of the above-mentioned second base material on the end face opposite to the above-mentioned color developing layer. When the surface with the uneven shape of the above-mentioned second base material is on one end face, since the surface with the uneven shape is located on the outermost layer, the design property based on the uneven shape is further improved.

[0027] The information recording medium for laser marking of the present invention preferably further includes an anchor layer. The above-mentioned anchor layer is a layer provided between the above-mentioned first base material and the above-mentioned color developing layer. Also, the information recording medium for laser marking of the present invention preferably further includes an intermediate layer. The above-mentioned intermediate layer is a layer provided between the above-mentioned color developing layer and the above-mentioned second base material. Also, the information recording medium for laser marking of the present invention preferably further includes a laminate layer. The above-mentioned laminate layer is a layer provided between the above-mentioned color developing layer and the above-mentioned second base material when there is no intermediate layer, and is a layer provided between the above-mentioned intermediate layer and the above-mentioned second base material when there is an intermediate layer. Further, it is preferable that the above-mentioned laminate layer is in contact with the above-mentioned second base material. Also, the information recording medium for laser marking of the present invention may include other layers other than the above. Examples of the above-mentioned other layers include a printing layer, an overcoat layer, a heat insulating layer, a protective layer, a light resistance improving layer, an adhesive layer, a release layer, a separator, and the like.

[0028] Hereinafter, an embodiment of the information recording medium for laser marking of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments.

[0029] FIG. 1 is a schematic cross-sectional view showing an embodiment of the information recording medium for laser marking of the present invention. As shown in FIG. 1, the information recording medium 1 for laser marking of the present embodiment has a laminated structure in which a color-developing layer 4 and a second substrate 7 are laminated in this order on a sheet-like first substrate 2, and the color-developing layer 4 is sandwiched between the first substrate 2 and the second substrate 7. Here, the first substrate 2 and / or the second substrate 7 is a layer that transmits ultraviolet rays. Further, the second substrate 7 has an uneven shape on at least one surface. Here, in the present specification, the surface of the second substrate 7 having the uneven shape may be referred to as an uneven surface. By satisfying the above configuration, the information recording medium 1 for laser marking of the present embodiment enables printing by laser marking with good printing quality while at least one surface of the second substrate 7 has an uneven shape.

[0030] The case where the first substrate 2 is a layer that transmits ultraviolet rays will be described as an example for laser marking. In this case, it is considered that the laser light irradiated on the first substrate 2 can pass through the first substrate 2 and act efficiently on the color-developing layer 4. And it is considered that the color-developing layer 4 can absorb the above laser light and develop color by its energy. Also, generally, since laser light has high energy, when the color-developing layer 4 absorbs the laser light, a phenomenon accompanied by some impact such as foaming, gasification, or shaving may occur. However, since the color-developing layer 4 is covered and protected by the first substrate 2, it is considered that the impact can be contained and laser marking can be performed without causing damage. Furthermore, since the first substrate 2 is a layer that transmits ultraviolet rays, it is considered that the first substrate 2 itself can avoid absorbing a large amount of laser light and being damaged such as having holes opened. Therefore, according to the information recording medium 1 for laser marking of the present embodiment, by irradiating laser light from the first substrate 2 side, a color-developed portion is generated in the color-developing layer 4, and laser marking becomes possible. Note that the same applies when the second substrate 7 is a layer that transmits ultraviolet rays, and laser marking becomes possible by irradiating laser light on the second substrate 7.

[0031] FIG. 2 is a schematic cross-sectional view showing another embodiment of the information recording body for laser marking of the present invention. As shown in FIG. 2, the information recording body 1 for laser marking of the present embodiment has a laminated structure in which an anchor layer 3, a coloring layer 4, an intermediate layer 5, a laminate layer 6, and a second substrate 7 are laminated in this order on a sheet-like first substrate 2. Here, the first substrate 2 and / or the second substrate 7 is a layer that transmits ultraviolet rays. Further, the second substrate 7 has an uneven shape on at least one surface. Also, the first substrate 2 and the anchor layer 3, the anchor layer 3 and the coloring layer 4, the coloring layer 4 and the intermediate layer 5, the intermediate layer 5 and the laminate layer 6, and the laminate layer 6 and the second substrate 7 are in contact with each other, respectively. By providing the anchor layer 3, the adhesion between the first substrate 2 and the coloring layer 4 is further improved, and delamination between layers can be more suppressed. Also, by providing the intermediate layer 5, the coloring layer 4 is protected, and adverse effects such as decolorization due to external factors are more suppressed, so that the print storage properties such as moisture and heat resistance can be more excellent. Also, by providing the laminate layer 6, the adhesion between the intermediate layer 5 and the second substrate 7 is further improved, and delamination between layers can be more suppressed.

[0032] (First Substrate) The first substrate 2 is a layer that can exhibit functions such as a function as a support of the information recording body 1 for laser marking, a function of protecting the coloring layer and the like, and a function of ensuring coatability. From the viewpoint of further improving the transmittance of laser light, the first substrate 2 is preferably a layer that transmits ultraviolet rays. Specifically, the first substrate 2 is preferably a layer that transmits at least a part of ultraviolet rays in the wavelength range of 10 to 400 nm, and more preferably a layer that transmits at least a part of ultraviolet rays with a wavelength exceeding 351 nm and 400 nm or less. Also, the first substrate 2 may be a single layer or a multi-layer.

[0033] From the viewpoint of further improving the coatability and / or the transparency of laser light, at least one surface of the first substrate 2 is preferably smooth, and more preferably both surfaces are smooth. As such a first substrate 2, for example, a substrate such as a commercially available known or conventional resin film can be appropriately used. Further, as the first substrate 2 having both smooth surfaces, a substrate such as a resin film whose both surfaces are not subjected to surface treatment such as embossing can be appropriately used.

[0034] Examples of the first substrate 2 include resin films and the like. Examples of the resin constituting the resin film include polyethylene (low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene), polypropylene (random copolymer polypropylene, block copolymer polypropylene, homopolypropylene), polybutene, polymethylpentene, ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate (random, alternating) copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, cyclic olefin-based polymer, ethylene-butene copolymer, ethylene-hexene copolymer and other polyolefin resins; polyurethane; polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT) and other polyesters; polystyrene; polycarbonate; polyimide-based resins; polyether ether ketone; polyether imide; polyamides such as aramid and wholly aromatic polyamide; polyphenyl sulfide; fluororesin; polyvinyl chloride; polyvinylidene chloride; cellulose resins such as triacetyl cellulose (TAC); silicone resins; acrylic resins such as polymethyl methacrylate (PMMA); polysulfone; polyarylate; polyvinyl acetate and the like. The above resins can be used alone or in combination of two or more. The above resin film may be stretched or not stretched.

[0035] The thickness of the first substrate 2 is not particularly limited. For example, it is preferably 5 μm or more, more preferably 10 μm or more. Also, the thickness of the first substrate 2 is not particularly limited. For example, it is preferably 150 μm or less, more preferably 100 μm or less. When the thickness is within the above range, the coatability and supportability can be more excellent.

[0036] From the viewpoint of further improving the physical strength, the thickness of the first substrate 2 may be 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, or 50 μm or more. When the first substrate 2 is a layer that transmits ultraviolet rays and laser light is irradiated on the first substrate 2, even if the thickness is within the above range, the laser light can act on the color developing layer 4 efficiently, so that color developability and physical strength can be compatible.

[0037] The haze of the first substrate 2 is not particularly limited. However, from the viewpoint of further improving visibility and / or laser marking suitability, it is preferably 30% or less, more preferably 20% or less, still more preferably 10% or less, still more preferably 5% or less, and particularly preferably 3% or less. The above haze can be measured by a conventional method. For example, it can be determined by a method in accordance with JIS K7136:2000. When the above haze is within the above range, the transparency of the first substrate 2 becomes higher, so that the visibility when visually recognizing the color developing portion in the color developing layer 4 through the first substrate 2 can be further improved. Also, when the above haze is within the above range, the transmittance of the laser light can be further improved, so that the color developability can be further improved and the damage to the first substrate 2 can be more suppressed, and thus the laser marking suitability can be further improved.

[0038] The total light transmittance of the first substrate 2 in the wavelength range of 300 nm to 400 nm is not particularly limited. However, from the viewpoint of further improving the laser marking suitability, it is preferably 40% or more, more preferably 50% or more, still more preferably 60% or more, and particularly preferably 70% or more. The total light transmittance in the wavelength range of 300 nm to 400 nm can be measured by a conventional method. For example, it can be determined by a method conforming to JIS K7375:2008. When the total light transmittance is within the above range, the transmittance of the laser light can be further improved, so that the color developability can be further improved, and the damage to the first substrate 2 can be further suppressed. Therefore, the laser marking suitability can be further improved. Further, the total light transmittance in the wavelength range exceeding 351 nm and 400 nm or less is preferably within the above range, the total light transmittance in the wavelength range exceeding 353 nm and 390 nm or less is preferably within the above range, and the total light transmittance in the wavelength range exceeding 353 nm and 360 nm or less is preferably within the above range.

[0039] (Second substrate) The second substrate 7 has an uneven shape on at least one surface. Further, the second substrate 7 may have an uneven shape on both surfaces. By the second substrate 7 having an uneven shape on at least one surface, the laser marking information recording body 1 can be imparted with a design property. Conventionally, such a substrate has been difficult to be used as a substrate for a thermal recording medium because coatability cannot be ensured for the uneven surface or the thermal head does not hit evenly due to the influence of the uneven surface, which may cause a decrease in printing quality. However, according to the present embodiment, it can be stably manufactured by the manufacturing method described later, and further, printing can be performed with good printing quality by a non-contact printing method such as laser marking. Further, the second substrate 7 may be a layer that transmits ultraviolet rays from the viewpoint of being easily permeable to laser light. The second substrate 7 may be a single layer or a multilayer.

[0040] The second substrate 7 is not particularly limited, and a substrate having an uneven shape on at least one surface can be appropriately used. Specifically, from the viewpoint of design, the second substrate 7 is preferably at least one selected from the group consisting of Japanese paper, non-woven fabric, and a resin film having an uneven shape on at least one surface. Examples of the resin constituting the resin film include the same ones as those exemplified in the item of the first substrate. Further, in the present embodiment, the resin film preferably has flexibility. By using such a resin film, the flexibility of the laser marking information recording body 1 becomes more appropriate, and operations such as bending and rounding can be easily applied, so that the handleability is further improved. As the resin film having an uneven shape on at least one surface, commercially available matte films, mesh films, etc. can be appropriately used.

[0041] From the viewpoint of further improving visibility and / or design, the opacity of the second substrate 7 is preferably 90% or less, more preferably 80% or less, still more preferably 70% or less, still more preferably 60% or less, still more preferably 55% or less, still more preferably 51% or less, still more preferably 50% or less, and particularly preferably 45% or less. The opacity can be measured by a conventional method, for example, by a method conforming to JIS P8149:2000. When the opacity is within the above range, the transparency of the second substrate 7 becomes higher, so that the visibility when visually recognizing the coloring portion in the coloring layer 4 through the second substrate 7 can be further improved.

[0042] In the uneven shape of the second substrate 7, the arithmetic mean height Sa may be 3.0 μm or more, may be 3.5 μm or more, or may be 10 μm or more. Further, in the uneven shape of the second substrate 7, the arithmetic mean height Sa may be 100 μm or less, may be 80 μm or less, or may be 50 μm or less. When the second substrate 7 has uneven shapes on both sides, the arithmetic mean height Sa of the surface opposite to the color developing layer 4 and the arithmetic mean height Sa of the surface on the color developing layer 4 side may be the same or different. When the arithmetic mean heights Sa of both sides of the second substrate 7 are different, the arithmetic mean heights Sa of both sides may both be within the above numerical range, or only the arithmetic mean height Sa of the surface opposite to the color developing layer 4 may be within the above numerical range. The arithmetic mean height Sa represents the average of the absolute values of the height differences of each point with respect to the average plane of the surface. When the arithmetic mean height Sa is 3.0 μm or more, the uneven shape becomes clearer, and more sufficient design and touch can be imparted. When the arithmetic mean height Sa is 100 μm or less, the thickness of the entire laser marking information recording body 1 becomes more appropriate, and the handleability is further improved.

[0043] In the uneven shape of the second substrate 7, the arithmetic mean curvature Spc of the convex vertex is 1000 mm -1 or more, may be 1500 mm -1 or more, may be 2000 mm -1 or more. Further, in the uneven shape of the second substrate 7, the arithmetic mean curvature Spc of the convex vertex is 10000 mm -1 or less, may be 5000 mm -1The following may be applicable. When the second substrate 7 has uneven shapes on both sides, the arithmetic mean curvature Spc of the convex vertices on the surface opposite to the color-developing layer 4 and the arithmetic mean curvature Spc of the convex vertices on the surface of the color-developing layer 4 side may be the same or different. When the arithmetic mean curvatures Spc of the convex vertices on both sides of the second substrate 7 are different, both the arithmetic mean curvatures Spc of the convex vertices on both sides may be within the above numerical range, or only the arithmetic mean curvature Spc of the convex vertices on the surface opposite to the color-developing layer 4 may be within the above numerical range. The arithmetic mean curvature Spc of the convex vertices represents the average of the principal curvatures of the convex vertices, and the larger the value, the sharper the vertex part indicates. When the arithmetic mean curvature Spc of the convex vertices is 1000 mm -1 or more, the convex vertex part becomes clearer, and more sufficient design and touch can be imparted. When the arithmetic mean curvature Spc of the convex vertices is 10000 mm -1 or less, the sharpness of the convex vertex part has an appropriate roundness and is more excellent in handleability.

[0044] In the uneven shape of the second substrate 7, the developed area ratio Sdr of the interface may be 0.5 or more, 1.0 or more, or 2.0 or more. Also, in the uneven shape of the second substrate 7, the developed area ratio Sdr of the interface may be 30 or less, 15 or less. When the second substrate 7 has uneven shapes on both sides, the developed area ratio Sdr of the interface on the surface opposite to the color-developing layer 4 and the developed area ratio Sdr of the interface on the surface of the color-developing layer 4 side may be the same or different. When the developed area ratios Sdr of the interfaces on both sides of the second substrate 7 are different, both the developed area ratios Sdr of the interfaces on both sides may be within the above numerical range, or only the developed area ratio Sdr of the interface on the surface opposite to the color-developing layer 4 may be within the above numerical range. The developed area ratio Sdr of the interface is an index representing how much the developed area (surface area) of the defined region increases with respect to the area of the defined region. In the case of a completely flat surface, the Sdr of that surface is 0, and in the case of a surface where the surface area increases by 10% due to the uneven shape, the Sdr of that surface is 0.1. When the developed area ratio Sdr of the interface is 0.5 or more, it means that the uneven shape is formed more densely, and more sufficient design and touch can be imparted.

[0045] The arithmetic mean height Sa, the arithmetic mean curvature Spc of the convex apex, and the developed area ratio Sdr of the interface can be measured by a conventional method. For example, they can be obtained by a method conforming to ISO25178 using a shape analysis laser microscope (e.g., manufactured by KEYENCE CORPORATION, device name: VK-X1000).

[0046] In the concavo-convex shape of the second substrate 7, from the viewpoint of further improving the designability, the Bekk smoothness may be 50 seconds or less, 40 seconds or less, 30 seconds or less, 20 seconds or less, 10 seconds or less, 5 seconds or less, or 3 seconds or less. When the second substrate 7 has concavo-convex shapes on both sides, the Bekk smoothness of the surface on the side opposite to the color developing layer 4 and the Bekk smoothness of the surface on the color developing layer 4 side may be the same or different. When the Bekk smoothness of both sides of the second substrate 7 is different, the Bekk smoothness of both sides may be within the above numerical range, or only the Bekk smoothness of the surface on the side opposite to the color developing layer 4 may be within the above numerical range. The above Bekk smoothness can be measured by a conventional method. For example, it can be obtained by a method conforming to JIS P8119:1998. When the second substrate 7 is a paper-based substrate such as Japanese paper or non-woven fabric, from the viewpoint of further improving the designability, its Bekk smoothness is preferably within the above range.

[0047] Note that the Bekk smoothness is one of the indexes for defining the smoothness of the surface of a sample piece such as paper. Specifically, it is obtained by pressing a test piece placed on the glass plane of the sample stage with a specific force, sucking atmospheric air from between the glass plane and the contact surface of the test piece by vacuum, and measuring the time required for a specific vacuum change. Here, the higher the smoothness of the surface of the test piece, the more time is required for air suction, so the numerical value (in seconds) becomes larger, and the lower the smoothness of the test surface, the smaller the numerical value (in seconds).

[0048] When the second base material 7 is a paper-based base material such as Japanese paper or non-woven fabric, its sizing degree may be 50 seconds or less, 40 seconds or less, 30 seconds or less, 20 seconds or less, 10 seconds or less, 5 seconds or less, or 3 seconds or less. The sizing degree can be measured by a conventional method. For example, it can be determined by the Stechi Hit method conforming to JIS P8122:2004. When it is within the above range, the transparency and texture of the second base material 7 increase, so the design property can be further improved. The second base material 7 with the sizing degree within the above range means that it is a base material through which water or coating liquid easily penetrates, so it may be inferior in coatability. However, according to the present embodiment, even such a second base material 7 can be suitably used.

[0049] Note that the sizing degree is an index representing the quality of a paper-based base material and is one of the indexes defining the resistance to penetration of water, ink, etc. Specifically, it is obtained by measuring the time required for water to contact the center of the test piece when water is absorbed from both sides of the test piece. Here, the higher the permeability of the test piece, the more quickly water is absorbed, so the numerical value (number of seconds) becomes smaller, and the lower the permeability of the test piece, the larger the numerical value (number of seconds).

[0050] The second base material 7 may be a layer having through-holes in the thickness direction. Generally, base materials such as Japanese paper with a sense of transparency and fluffiness and excellent texture, and resin films to which design properties are imparted by perforation processing, embossing processing, etc. have through-holes or irregularities in the thickness direction. In conventional thermal recording bodies, when using such a base material, when coating, the coating liquid penetrates in the thickness direction and immediately leaks through, or the coating liquid flows along the shape of the recess, so it has been difficult to ensure coatability. However, according to the present embodiment, even such a second base material 7 can be suitably used.

[0051] The thickness of the second base material 7 is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm. When the thickness is within the above range, the visibility and design property can be more excellent.

[0052] When the second substrate 7 is a resin film having an uneven shape on at least one surface, its thickness may be 100 μm or less, 80 μm or less, 60 μm or less, or 40 μm or less. When the thickness is within the above range, sufficient designability can be imparted while further imparting sufficient flexibility.

[0053] (Anchor layer) The anchor layer 3 is a layer for the purpose of enhancing the adhesion between the first substrate 2 and the color developing layer 4. The anchor layer 3 may not be provided if not necessary, and in that case, the color developing layer 4 can be directly laminated on the first substrate 2. The material for forming the anchor layer 3 is not particularly limited, and for example, it can be formed using a resin. Also, the anchor layer 3 may contain other components. Examples of the other components include surfactants, preservatives, inorganic pigments, organic pigments, viscosity modifiers, and the like.

[0054] Examples of the resin include acrylic resins such as acrylic resin, styrene-acrylic resin, acrylic-urethane resin, acrylic-amide resin, vinyl acetate-acrylic resin; maleic acid resins such as maleic acid resin, styrene-maleic acid resin, olefin-maleic acid resin; styrene butadiene latex (SBR) resin, and the like. These resins may be modified resins modified by known methods. Also, these resins can be used alone or in combination of two or more.

[0055] As used herein, the term "acrylic resin" means a resin obtained by homopolymerizing an acrylic monomer (acrylic resin), and / or a resin obtained by copolymerizing an acrylic monomer and another monomer (a monomer other than an acrylic monomer copolymerizable with the acrylic monomer). Here, the above-mentioned other monomer may be one kind or two or more kinds. Further, when simply described as "acrylic", unless otherwise specified, it means (meth)acrylic acid (salt) and / or (meth)acrylate. Here, "(meth)acrylic acid" means acrylic acid and / or methacrylic acid, and "(meth)acrylic acid (salt)" means (meth)acrylic acid and / or (meth)acrylate salt.

[0056] The salt in the above-mentioned (meth)acrylate is not particularly limited, and examples thereof include ammonium salts such as ammonia; alkanolamine salts such as triethanolamine, diethanolamine, and monoethanolamine; alkylamine salts such as methylamine salt, ethylamine salt, diethylamine salt, and triethylamine salt; polyamine salts such as diethyleneamine salt and diethylenetriamine salt; alkali metal salts such as lithium, sodium, and potassium; alkaline earth metal salts such as magnesium and calcium; polyvalent metal salts such as zinc and iron. These salts can be used alone or in combination of two or more.

[0057] The composition forming the above resin may be solid, emulsion, or solution. From the viewpoint of excellent handleability and coatability, it is preferably an emulsion or a solution.

[0058] Examples of the above surfactant include anionic surfactants such as sodium dioctyl sulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and alkyl ether sulfate ester salts; nonionic surfactants such as acetylene glycol and alkylene oxide adducts of acetylene glycol. These surfactants can be used alone or in combination of two or more.

[0059] As the coating amount (dry mass) of the anchor layer 3, for example, 0.1 g / m 2 ~5.0 g / m 2 is preferable, more preferably 0.3 g / m 2 ~4.0 g / m 2 and even more preferably 0.5 g / m 2 ~3.0 g / m 2 When the coating amount is within the above range, the adhesion between layers becomes more appropriate, and delamination between layers can be more suppressed.

[0060] (Color-developing layer) The color-developing layer 4 is a layer that develops color by the energy of laser light and forms a recorded image on the laser marking information recording medium 1. The material for forming the color-developing layer 4 is not particularly limited, and known materials can be appropriately used. For example, from the viewpoint of performing printing with excellent color-developing property and contrast by laser marking, the color-developing layer 4 preferably contains at least a leuco dye and a developer. The above developer may or may not contain a non-phenolic developer. From the viewpoint of environmental response and the like, the above developer preferably contains a non-phenolic developer.

[0061] The color-developing layer 4 may further contain other components as necessary. Examples of the above other components include a binder, a filler, a lubricant, a dispersant, a cross-linking agent, a preservative, a sensitizer, a surfactant, a viscosity modifier, and the like.

[0062] Examples of the above non-phenolic developer include urea compounds. As the above urea compound, one or more sulfonic acid ester structures (-S(=O) 2N, N'- diarylurea derivatives having (-O-) are preferred. Specifically, as the above N, N'- diarylurea derivatives, it is preferable to include a compound represented by the following formula (1) and / or a compound represented by the following formula (2), and it is more preferable to include a compound represented by the following formula (1). In the present specification, the "urea compound" means a compound having one or more urea bonds (-NH-C(=O)-NH-) in the molecule, and the "N, N'- diarylurea derivative" means a compound having an N, N'- diarylurea skeleton.

[0063]

Chemical formula

Chemical formula

[0064] The compound represented by the above formula (1) and / or the compound represented by the above formula (2) can react with, for example, a leuco dye described later by the energy of laser light and develop color.

[0065] In the above formula (1) and the above formula (2), R 1 is a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and a plurality of R 1 may be the same or different. A 1 is a hydrocarbon group having 1 to 4 carbon atoms, and a plurality of A 1 may be the same or different. m represents an integer of 0 to 4, and when m is 2 or more, a plurality of m may be the same or different.

[0066] In the above formula (1), the plurality of Rs 1 -SO 3 - is directly bonded to the carbon atom constituting the benzene ring. Also, the plurality of Rs 1 -SO 3 - may have the same or different substitution positions. The substitution position of R 1 -SO 3 - is preferably at the 2nd, 3rd, or 4th position, more preferably at the 3rd position.

[0067] In the above formula (2), R 1 -SO 3 - is directly bonded to the carbon atom constituting the benzene ring. The substitution position of R 1 -SO 3 - is preferably at the 2nd, 3rd, or 4th position, more preferably at the 3rd position.

[0068] In the above formula (1) and the above formula (2), among the "hydrocarbon group having 1 to 12 carbon atoms which may have a substituent" of the above R 1 , examples of the "hydrocarbon group having 1 to 12 carbon atoms" include a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 1 to 12 carbon atoms, an alicyclic alkyl group having 3 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and the like. Also, the plurality of "hydrocarbon groups having 1 to 12 carbon atoms which may have a substituent" may be the same or different.

[0069] Examples of the above "linear alkyl group having 1 to 12 carbon atoms, branched alkyl group having 1 to 12 carbon atoms, alicyclic alkyl group having 3 to 12 carbon atoms" include linear alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, cyclopentyl group, hexyl group, cyclohexyl group, 2-ethylhexyl group, lauryl group, branched alkyl groups having 1 to 12 carbon atoms, or alicyclic alkyl groups having 3 to 12 carbon atoms. These alkyl groups may further have a substituent described later.

[0070] Examples of the above-mentioned "aralkyl group having 7 to 12 carbon atoms" include unsubstituted aralkyl groups such as benzyl group, 1-phenylethyl group, 2-phenylethyl group, 3-phenylpropyl group, etc. Further, these aralkyl groups may further have substituents described below. Examples of the "aralkyl group having 7 to 12 carbon atoms and having a substituent" include aralkyl groups having substituents such as p-methylbenzyl group, m-methylbenzyl group, m-ethylbenzyl group, p-ethylbenzyl group, p-i-propylbenzyl group, p-t-butylbenzyl group, p-methoxybenzyl group, m-methoxybenzyl group, o-methoxybenzyl group, m,p-di-methoxybenzyl group, p-ethoxy-m-methoxybenzyl group, p-phenylmethylbenzyl group, p-cumylbenzyl group, p-phenylbenzyl group, o-phenylbenzyl group, m-phenylbenzyl group, p-tolylbenzyl group, m-tolylbenzyl group, o-tolylbenzyl group, p-chlorobenzyl group, etc.

[0071] Examples of the above-mentioned "aryl group having 6 to 12 carbon atoms" include unsubstituted aryl groups such as phenyl group, 1-naphthyl group, 2-naphthyl group, etc. Further, these aryl groups may further have substituents described below. Examples of the "aryl group having 6 to 12 carbon atoms and having a substituent" include aryl groups having substituents such as p-tolyl group, m-tolyl group, o-tolyl group, 2,5-dimethylphenyl group, 2,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,3-dimethylphenyl group, 3,4-dimethylphenyl group, mesitylene group, p-ethylphenyl group, p-i-propylphenyl group, p-t-butylphenyl group, p-methoxyphenyl group, 3,4-dimethoxyphenyl group, p-ethoxyphenyl group, p-chlorophenyl group, t-butylated naphthyl group, etc.

[0072] The above-mentioned "substituent" is not particularly limited. Among the above-mentioned "hydrocarbon group having 1 to 12 carbon atoms which may have a substituent", when the "hydrocarbon group having 1 to 12 carbon atoms" is a "linear alkyl group having 1 to 12 carbon atoms or a branched alkyl group having 1 to 12 carbon atoms", examples of the substituent include a halogen atom, an alkoxy group, and the like. Further, among the above-mentioned "hydrocarbon group having 1 to 12 carbon atoms which may have a substituent", when the "hydrocarbon group having 1 to 12 carbon atoms" is a "cycloalkyl group having 3 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms", examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an aryl group, and the like. Among them, the substituent is preferably an alkyl group or an alkoxy group. Here, the number of carbon atoms of the alkyl group and the alkoxy group as the substituent is not particularly limited, but among them, 1 to 6 carbon atoms are preferable, and 1 to 4 carbon atoms are more preferable. The above-mentioned "substituent" may be plural or may not be present. Further, the substitution positions of the plural "substituents" may be the same or different. The substitution position of the above-mentioned "substituent" is preferably any one of the 2-position, 3-position, or 4-position of the aralkyl group or the aryl group, and more preferably the 4-position.

[0073] In the above formula (1) and the above formula (2), the above R 1 is preferably an aryl group having 6 to 12 carbon atoms which is unsubstituted or has a substituent. More specifically, the above R 1 is preferably a phenyl group, a p-tolyl group, an m-tolyl group, an o-tolyl group, a 2,5-dimethylphenyl group, a 2,4-dimethylphenyl group, a 3,5-dimethylphenyl group, a 2,3-dimethylphenyl group, a 3,4-dimethylphenyl group, and among them, the p-tolyl group is more preferable. When it is such an R 1 the sensitivity becomes more excellent.

[0074] In the above formula (1) and the above formula (2), the above A 1 is a carbon atom constituting a benzene ring, and can be bonded to a carbon atom to which the above R 1 -SO 3 - is not bonded. Further, a plurality of A 1The substitution positions may be the same or different even if they are the same substitution position. The above A 1 The substitution positions of are preferably the 2nd, 3rd, and 4th positions.

[0075] In the above formula (1) and the above formula (2), the above m is preferably an integer of 0 to 2, more preferably an integer of 0 to 1, and even more preferably 0.

[0076] The above A 1 Examples of the hydrocarbon group having 1 to 4 carbon atoms of include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, and t-butyl group.

[0077] Specific examples of the compound represented by the above formula (1) include, but are not limited to, the following compounds.

[0078] That is, as the compound represented by the above formula (1), N,N'-di-[3-(o-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-toluenesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[3-(p-xylenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-xylenesulfonyloxy)phenyl]urea, N,N'-di-[3-(mesitylenesulfonyloxy)phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-ethyl-phenyl]urea, N,N’-di-[3-(benzenesulfonyloxy)-5-methyl-phenyl]urea, N,N’-di-[3-(benzenesulfonyloxy)-4-propyl-phenyl]urea,

[0079] N,N'-Di-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-propylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-isopropylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-t-butylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(o-methoxybenzenesulfonyloxy)phenyl]urea,

[0080] N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(p-toluenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(m-toluenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(o-toluenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N’-[3-(p-xylenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N’-[3-(mesitylenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N’-[3-(1-naphthalenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N’-[3-(2-naphthalenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N’-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(benzylsulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(ethanesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(benzenesulfonyloxy)-4-methylphenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N’-[3-(m-toluenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N’-[3-(o-toluenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[3-(p-toluenesulfonyloxy)-4-methylphenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N’-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea,

[0081] N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(benzylsulfonyloxy)phenyl]urea, N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(p-methylbenzylsulfonyloxy)phenyl]urea, N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0082] N,N'-Di-[4-(benzenesulfonyloxy)phenyl]urea, N,N'-Di-[4-(benzenesulfonyloxy)-3-methyl-phenyl]urea, N,N'-Di-[4-(benzenesulfonyloxy)-3-ethyl-phenyl]urea, N,N'-Di-[4-(benzenesulfonyloxy)-3-propyl-phenyl]urea, N,N'-Di-[4-(benzenesulfonyloxy)-3-t-butyl-phenyl]urea,

[0083] N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(p-toluenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(m-toluenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(o-toluenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(p-xylenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(mesitylenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N’-[4-(1-naphthalenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N’-[4-(2-naphthalenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N’-[4-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N’-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N’-[4-(benzylsulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N’-[4-(ethanesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N’-[4-(m-toluenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N’-[4-(o-toluenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N’-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N’-[4-(2-naphthalenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N’-[4-(benzylsulfonyloxy)phenyl]urea,N-[4-(p-Toluenesulfonyloxy)phenyl]-N’-[4-(p-methylbenzylsulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N’-[4-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0084] N,N'-Di-[4-(benzylsulfonyloxy)phenyl]urea, N,N'-Di-[4-(benzylsulfonyloxy)-3-methyl-phenyl]urea, N,N'-Di-[4-(phenylethanesulfonyloxy)phenyl]urea, N,N'-Di-[4-(phenylpropanesulfonyloxy)phenyl]urea, N,N'-Di-[4-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0085] N,N'-Di-[2-(benzenesulfonyloxy)phenyl]urea, N,N'-Di-[2-(benzenesulfonyloxy)-4-methyl-phenyl]urea, N,N'-Di-[2-(benzenesulfonyloxy)-4-ethyl-phenyl]urea, N,N'-Di-[2-(benzenesulfonyloxy)-5-methyl-phenyl]urea, N,N'-Di-[2-(benzenesulfonyloxy)-4-propyl-phenyl]urea,

[0086] N,N'-Di-[2-(o-toluenesulfonyloxy)phenyl]urea, N,N'-Di-[2-(m-toluenesulfonyloxy)phenyl]urea, N,N'-Di-[2-(p-toluenesulfonyloxy)phenyl]urea, N,N'-Di-[2-(p-toluenesulfonyloxy)-4-methyl-phenyl]urea,

[0087] N,N'-Di-[2-(p-xylenesulfonyloxy)phenyl]urea, N,N'-di-[2-(m-xylenesulfonyloxy)phenyl]urea, N,N'-di-[2-(mesitylenesulfonyloxy)phenyl]urea, and the like can be mentioned. Among them, as the compound represented by the above formula (1), from the viewpoint that good color development by laser light can be achieved and excellent moisture and heat resistance can also be obtained, N,N'-di-[3-(p-toluenesulfonyloxy)phenyl]urea is particularly preferred.

[0088] In addition, as specific compounds of the compound represented by the above formula (2), for example, the following compounds can be mentioned, but are not limited to these compounds.

[0089] That is, as the compound represented by the above formula (2), 3-[(3-phenylureido)phenyl]-4-methylbenzenesulfonate, 4-[(3-phenylureido)phenyl]-4-methylbenzenesulfonate, 2-[(3-phenylureido)phenyl]-4-methylbenzenesulfonate, 3-[(3-phenylureido)phenyl]-2-methylbenzenesulfonate, 4-[(3-phenylureido)phenyl]-2-methylbenzenesulfonate, 2-[(3-phenylureido)phenyl]-2-methylbenzenesulfonate, 3-[(3-phenylureido)phenyl]-3-methylbenzenesulfonate, 4-[(3-phenylureido)phenyl]-3-methylbenzenesulfonate, 2-[(3-phenylureido)phenyl]-3-methylbenzenesulfonate, 3-[(3-phenylureido)phenyl]-benzenesulfonate, 4-[(3-phenylureido)phenyl]-benzenesulfonate, 2-[(3-phenylureido)phenyl]-benzenesulfonate,

[0090] 3-[3-(4-Methylphenylureido)]phenyl-4-methylbenzenesulfonate, 4-[3-(4-methylphenylureido)]phenyl-4-methylbenzenesulfonate, 2-[3-(4-methylphenylureido)]phenyl-4-methylbenzenesulfonate, 3-[3-(4-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 4-[3-(4-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 2-[3-(4-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 3-[3-(4-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 4-[3-(4-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 2-[3-(4-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 3-[3-(4-methylphenylureido)]phenyl-benzenesulfonate, 4-[3-(4-methylphenylureido)]phenyl-benzenesulfonate, 2-[3-(4-methylphenylureido)]phenyl-benzenesulfonate,

[0091] 3-[3-(2-Methylphenylureido)]phenyl-4-methylbenzenesulfonate, 4-[3-(2-methylphenylureido)]phenyl-4-methylbenzenesulfonate, 2-[3-(2-methylphenylureido)]phenyl-4-methylbenzenesulfonate, 3-[3-(2-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 4-[3-(2-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 2-[3-(2-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 3-[3-(2-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 4-[3-(2-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 2-[3-(2-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 3-[3-(2-methylphenylureido)]phenyl-benzenesulfonate, 4-[3-(2-methylphenylureido)]phenyl-benzenesulfonate, 2-[3-(2-methylphenylureido)]phenyl-benzenesulfonate,

[0092] 3-[3-(3-Methylphenylureido)]phenyl-4-methylbenzenesulfonate, 4-[3-(3-methylphenylureido)]phenyl-4-methylbenzenesulfonate, 2-[3-(3-methylphenylureido)]phenyl-4-methylbenzenesulfonate, 3-[3-(3-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 4-[3-(3-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 2-[3-(3-methylphenylureido)]phenyl-2-methylbenzenesulfonate, 3-[3-(3-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 4-[3-(3-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 2-[3-(3-methylphenylureido)]phenyl-3-methylbenzenesulfonate, 3-[3-(3-methylphenylureido)]phenyl-benzenesulfonate, 4-[3-(3-methylphenylureido)]phenyl-benzenesulfonate, 2-[3-(3-methylphenylureido)]phenyl-benzenesulfonate,

[0093] 3-(3-Phenylureido)phenyl-4-propyloxybenzenesulfonate, 4-(3-phenylureido)phenyl-4-propyloxybenzenesulfonate, 2-(3-phenylureido)phenyl-4-propyloxybenzenesulfonate, 3-(3-phenylureido)phenyl-4-phenyloxybenzenesulfonate, 4-(3-phenylureido)phenyl-4-phenyloxybenzenesulfonate, 2-(3-phenylureido)phenyl-4-phenyloxybenzenesulfonate and the like can be mentioned. Among them, as the compound represented by the above formula (2), from the viewpoint that good color developability by laser light can be achieved and excellent heat and humidity resistance can also be obtained, 3-[(3-phenylureido)phenyl]-4-methylbenzenesulfonate is particularly preferable.

[0094] As the color former, it may contain the compound represented by the above formula (1) alone, or may contain two or more compounds represented by the above formula (1). Similarly, as the color former, it may contain the compound represented by the above formula (2) alone, or may contain two or more compounds represented by the above formula (2). Further, the color former may contain both the compound represented by the above formula (1) and the compound represented by the above formula (2).

[0095] The color former may contain a color former other than the color formers exemplified above (other color formers) within a range not impairing the effects of the present invention.

[0096] Examples of the other color formers include known non-phenolic color formers such as N-3-[(p-toluenesulfonyl)oxy]phenyl-N'-(p-toluenesulfonyl)-urea (trade name: PF-201), N-[2-(3-phenylureido)phenyl]-benzenesulfonamide (trade name: NKK-1304), 4,4'-bis[(4-methyl-3-phenoxycarbonylaminophenyl)ureido]diphenylsulfone (trade name: UU), etc., and known color formers such as 4,4'-isopropylidenediphenol (BPA), 4,4'-dihydroxydiphenylsulfone (BPS), 4-allyloxy-4'-hydroxydiphenylsulfone (trade name: BPS-MAE), 4-allyloxy-4'-hydroxy-diphenylsulfone (trade name: TGSA), 4-hydroxy-4'-propoxydiphenylsulfone, 4-hydroxy-4'-isopropoxysulfone (trade name: D-8), N-(m-tolylaminocarbonyl)-methionine, N-(m-tolylaminocarbonyl)-phenylalanine, and N-(phenylaminocarbonyl)-phenylalanine.

[0097] Furthermore, examples of other color developers include 1,1-bis(p-hydroxyphenyl)cyclohexane, 1,1-bis(p-hydroxyphenyl)propane, 2,2-bis(p-hydroxyphenyl)propane, 2,2-bis(p-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2'-methylenebis(4-chlorophenol), 2,2-bis(4-hydroxyphenyl)-4-methylpentane, poly(4-hydroxybenzoic acid), benzyl 4-hydroxybenzoate, 2,4-bis(phenylsulfonyl)phenol, α-{4-[(4-hydroxyphenyl)sulfonyl]phenyl}-ω-hydroxy poly (degree of polymerization n = 1 to 7) (oxyethylene oxyethylene oxy-p-phenylene sulfonyl-p-phenylene), 3,5-bis(α-methylbenzyl)salicylic acid, bis[zinc 4-(n-octyloxycarbonylamino)salicylate], 4,4'-bis(p-tolylsulfonylaminocarbonylamino)diphenylmethane, 4-hydroxybenzenesulfonanilide, N-(2-hydroxyphenyl)-2-[(4-hydroxyphenyl)thio]acetamide, N-(4-hydroxyphenyl)-2-[(4-hydroxyphenyl)thio]acetamide, 4-[4-[4-[4-[[4-(1-methylethoxy)phenyl]sulfonylphenoxy]butoxy]phenyl]sulfonyl]phenol, 4-tert-butylphenol·formaldehyde polycondensate, and the like.

[0098] The content ratio of the above color developer is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more with respect to 100% by mass of the total solid content of the color-forming layer 4. When the above content ratio is 10% by mass or more, the sensitivity can be further improved. Also, the content ratio of the above color developer is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less with respect to 100% by mass of the total solid content of the color-forming layer 4.

[0099] When the color developing layer 4 contains a non-phenolic color developer, the content ratio of the non-phenolic color developer is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 90% by mass or more, based on 100% by mass of the total amount of the color developers in the color developing layer 4. It may also be 100% by mass. When the content ratio is within the above range, the environmental load can be further suppressed. Also, the total content ratio of the compound represented by the above formula (1) and / or the compound represented by the above formula (2) is preferably within the above range based on 100% by mass of the total amount of the color developers in the color developing layer 4.

[0100] The melting point of the above color developer is not particularly limited. For example, it is preferably 130°C or higher, more preferably 140°C or higher, and still more preferably 150°C or higher. Also, the melting point of the above color developer is preferably 195°C or lower, more preferably 185°C or lower, for example. Further, the melting point of the above non-phenolic color developer is preferably within the above range. When the melting point is within the above range, the sensitivity to laser light can be adjusted to a more appropriate range, the laser marking suitability can be further improved, and the heat resistance and moisture-heat resistance can also be excellent.

[0101] The above-mentioned leuco dye is not particularly limited. For example, 2'-bromo-6'-(dibutylamino)-3'-methylspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one, 3-(1-ethyl-2-methylindol-3-yl)-3-(4-diethylamino-2-methylphenyl)-4-azaphthalide, 6-(dimethylamino)-3,3-bis[4-(dimethylamino)phenyl]-1(3H)-isobenzofuranone, 1,2-dihydro-1-ethyl-8-[N-(4-methylphenyl)-N-ethylamino]-2,2,4-trimethylspiro[11H]-chromeno(2,3-g)quinoline-11,3'-phthalide, 2'-[bis(phenylmethyl)amino]-6'-(diethylamino)-spiro[isobenzofuran-1(3H),9'-(9H)xanthene]-3-one, 3-(N-isobutyl-N-ethyl)amino-6-methyl-7-anilinofluoran, 3-(N-isopentyl-N-ethyl)amino-6-methyl-7-o-chloroanilinofluoran, 3-(N-methyl-N-p-toluidino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-p-toluidino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isopentyl)amino-6-methyl-7-anilinofluoran, 3-(N-ethoxypropyl-N-ethyl)amino-6-methyl-7-anilinofluoran, 3-(N-cyclohexyl-N-methyl)amino-6-methyl-7-anilinofluoran, 3-(N-methyl-N-n-propyl)amino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-p-toluidinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-8-methylfluoran, 3-diethylamino-7-(m-trifluoromethylanilino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-diethylamino-7-chlorofluoran, 3-dibutylamino-6-methyl-7-bromofluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, 3-dimethylamino-5-methyl-7-methylfluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, crystal violet lactone and the like can be mentioned. These leuco dyes can be used alone or in combination of two or more kinds.,

[0102] The average particle diameter of the above-mentioned leuco dye is not particularly limited, but is preferably 0.1 μm to 1.0 μm. Generally, since the leuco dye melts and reacts, as the average particle diameter increases, the reaction becomes sluggish and the sensitivity characteristics decrease. On the other hand, as the average particle diameter decreases, the risk of unexpected color development due to heat or the like during drying of the coating solution increases. By setting the average particle diameter of the leuco dye within the above range, the sensitivity characteristics and color development temperature of the leuco dye can be appropriately adjusted. In this specification, the average particle diameter means the particle diameter (D50, median diameter) at the integrated value 50% in the particle size distribution measured by the laser diffraction / scattering method. The average particle diameter by the laser diffraction / scattering method can be measured using a laser diffraction / scattering type particle size distribution measuring device (for example, manufactured by Microtrac Bell Co., Ltd., device name: MT3300EX-II).

[0103] The content ratio of the above-mentioned leuco dye is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 15% by mass or more with respect to 100% by mass of the total solid content of the color developing layer 4. When the above content ratio is 5% by mass or more, the sensitivity can be further improved. Also, the content ratio of the above-mentioned leuco dye is preferably 40% by mass or less, more preferably 30% by mass or less with respect to 100% by mass of the total solid content of the color developing layer 4.

[0104] The above binder includes, for example, acrylic resins such as acrylic resin, styrene-acrylic resin, acrylic-urethane resin, acrylic-amide resin, vinyl acetate-acrylic resin; maleic acid resins such as maleic acid resin, styrene-maleic acid resin, olefin-maleic acid resin; resins such as styrene butadiene latex (SBR) resin. These resins may be modified resins modified by known methods. Also, starch, casein, gelatin, polyamide, polyacrylamide, modified polyacrylamide, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl acetate, isobutylene-maleic anhydride copolymer, diisobutylene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, methyl vinyl-maleic anhydride copolymer, isopropylene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, polyurethane, polystyrene, polyvinyl pyrrolidone, acrylonitrile, methyl vinyl ether, etc. may be mentioned. These binders can be used alone or in combination of two or more kinds.

[0105] The content ratio of the above binder is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and particularly preferably 25% by mass or more with respect to 100% by mass of the total solid content of the color developing layer 4. Also, the content ratio of the above binder is preferably 60% by mass or less, more preferably 50% by mass or less with respect to 100% by mass of the total solid content of the color developing layer 4.

[0106] The above lubricants include, for example, hydrocarbon waxes such as paraffin, polyethylene, polystyrene; ester waxes such as carnauba wax; oils such as silicone oil, whale oil; fatty acids such as oleic acid; metal soaps such as zinc stearate, etc. These lubricants can be used alone or in combination of two or more kinds.

[0107] The content ratio of the above lubricant is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably 1% by mass or more with respect to 100% by mass of the total solid content of the color developing layer 4. Also, the content ratio of the above lubricant is preferably 10% by mass or less, more preferably 5% by mass or less with respect to 100% by mass of the total solid content of the color developing layer 4.

[0108] Examples of the above dispersant include anionic surfactants such as sodium dialkyl sulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and alkyl ether sulfate salts; nonionic surfactants such as acetylene glycol and alkylene oxide adducts of acetylene glycol; polyvinyl alcohols such as fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, and sulfonic acid-modified polyvinyl alcohol; and polymer dispersants such as styrene-acrylic copolymers and acrylic resins. These dispersants can be used alone or in combination of two or more.

[0109] The content ratio of the above dispersant is preferably 0.1% by mass or more, more preferably 1% by mass or more, and still more preferably 5% by mass or more with respect to 100% by mass of the total solid content of the color developing layer 4. Also, the content ratio of the above dispersant is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less with respect to 100% by mass of the total solid content of the color developing layer 4.

[0110] Examples of the above filler include inorganic fillers such as aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, aluminum silicate, calcium carbonate, magnesium carbonate, barium sulfate, silica gel, activated clay, talc, clay, kaolin, calcined kaolin, diatomaceous earth, white carbon, silicon oxide, silica, colloidal silica, and titanium oxide; and organic fillers such as styrene-acrylic resin particles, polystyrene resin particles, urea-formalin resin particles, and polyolefin resin particles. These fillers can be used alone or in combination of two or more.

[0111] The content ratio of the above filler is preferably 0.1% by mass or more, more preferably 1% by mass or more, and still more preferably 5% by mass or more, based on 100% by mass of the total solid content of the color - forming layer 4. Also, the content ratio of the above filler is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less, based on 100% by mass of the total solid content of the color - forming layer 4.

[0112] Examples of the above cross - linking agent include organic cross - linking agents such as cationic cross - linking agents and non - cationic cross - linking agents; inorganic cross - linking agents such as zirconium carbonate. Examples of the above cationic cross - linking agent include epichlorohydrin - based resins such as polyamide epichlorohydrin resin, polyamine epichlorohydrin resin, and polyamide polyamine epichlorohydrin resin. Examples of the above non - cationic cross - linking agent include oxazoline - based compounds such as oxazoline - group - containing polymers and oxazoline - group - containing low - molecular substances. These cross - linking agents can be used alone or in combination of two or more.

[0113] The content ratio of the above cross - linking agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably 1% by mass or more, based on 100% by mass of the total solid content of the color - forming layer 4. Also, the content ratio of the above cross - linking agent is preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less, based on 100% by mass of the total solid content of the color - forming layer 4.

[0114] The color - forming layer 4 may further contain a laser sensitizer. Examples of the above laser sensitizer include heavy - metal compounds. Specifically, for example, copper compounds such as copper phosphonate; molybdenum compounds such as amine molybdate; zinc compounds such as zinc oxide and zinc borate; cerium compounds such as cerium oxide; nickel compounds such as nickel oxide. In this specification, "heavy metal" means a specific gravity of 5.0 g / cm 3This means the above metal elements. Also, the color - developing layer 4 may not contain the above laser sensitizer. According to the information recording body 1 for laser marking of the present embodiment, since clear color development can be achieved without using a laser sensitizer, the environmental load can be further reduced.

[0115] The content ratio of the above laser sensitizer may be 20 mass% or less, 15 mass% or less, 10 mass% or less, 5 mass% or less, 3 mass% or less, 1 mass% or less, or 0.1 mass% or less with respect to 100 mass% of the total solid content of the color - developing layer 4.

[0116] The coating amount (dry mass) of the color - developing layer 4 is, for example, 0.3 g / m 2 ~10 g / m 2 is preferable, and more preferably 2.5 g / m 2 ~6.5 g / m 2 When the coating amount is within the above range, the color - developing property of the obtained information recording body 1 for laser marking can be made more appropriate.

[0117] (Intermediate layer) The intermediate layer 5 is a layer whose purpose is to further improve the print storage property (such as moisture - and heat - resistance) of the information recording body 1 for laser marking by suppressing the adverse effect that external factors such as chemicals migrate to the color - developing layer 4 and the color - developing density decreases. Among them, when the information recording body 1 for laser marking of the present embodiment includes the second base material 7 and the laminate layer 6, oil - soluble components in the second base material 7 and the laminate layer 6 may migrate to the color - developing layer 4, resulting in a problem of moisture - and heat - resistance that the color - developing density decreases during storage, especially during storage in a high - temperature and high - humidity environment. In such a case, by providing the intermediate layer 5 between the color - developing layer 4 and the second base material 7 or the laminate layer 6, the migration of oil - soluble components in the second base material 7 and the laminate layer 6 to the color - developing layer 4 can be suppressed, and the above - mentioned moisture - and heat - resistance can be improved.

[0118] The information recording medium 1 for laser marking according to this embodiment may or may not include an intermediate layer 5. From the viewpoint of further improving the print storage properties such as moisture and heat resistance, it is preferable to include the intermediate layer 5. The intermediate layer 5 can be mainly formed of a resin. The resin is not particularly limited, but preferably includes a resin having a water-soluble portion. The intermediate layer 5 may further contain other components as necessary. Examples of the other components include a crosslinking agent, a surfactant, a preservative, an inorganic pigment, an organic pigment, and the like. Among them, the intermediate layer 5 preferably contains a crosslinking agent. When the intermediate layer 5 contains a resin having a water-soluble portion, the water-soluble portion can more effectively suppress the migration of oil-soluble components in the second substrate 7, the laminate layer 6, and the like. Further, when the intermediate layer 5 contains a crosslinking agent, a dense crosslinked structure can be formed in the intermediate layer 5, so that the crosslinked structure portion can more effectively suppress the migration of oil-soluble components in the second substrate 7, the laminate layer 6, and the like.

[0119] Examples of the resin having a water-soluble portion include a hydroxy group-containing resin such as a polyvinyl alcohol (PVA) resin having a hydroxy group as the water-soluble portion; a carboxy group-containing resin such as an acrylic resin having a carboxy group as the water-soluble portion. Among them, the resin having a water-soluble portion is preferably a carboxy group-containing resin. Since the carboxy group is a highly hydrophilic functional group, it is particularly excellent in the effect of suppressing the migration of oil-soluble components into the color developing layer 4, and is considered to be able to form a crosslinked structure with a crosslinking agent described later.

[0120] The resin having a water-soluble portion is preferably a core-shell type resin. As used herein, the "core-shell type resin" means a resin having a structure in which hydrophobic core particles are coated with a water-soluble shell polymer.

[0121] Among the above core-shell type resins, as the water-soluble portion, a core-shell type resin having a carboxy group (core-shell type carboxy group-containing resin) is preferable. Here, it is considered that the above core-shell type carboxy group-containing resin contains a carboxy group in at least the structure of the water-soluble shell polymer.

[0122] Examples of the above core-shell type carboxy group-containing resin include core-shell type acrylic resins such as core-shell type acrylic resins, core-shell type styrene-acrylic resins, core-shell type acrylic-urethane resins, core-shell type acrylic-amide resins, and core-shell type vinyl acetate-acrylic resins; core-shell type maleic acid resins, and the like. As the above core-shell type carboxyl group-containing resin, a core-shell type acrylic resin is preferable, and among them, at least one selected from the group consisting of core-shell type acrylic resins, core-shell type styrene-acrylic resins, and core-shell type acrylic-urethane resins is more preferable, and at least one selected from the group consisting of core-shell type acrylic resins and core-shell type styrene-acrylic resins is even more preferable. Examples of the above core-shell type acrylic resin include resins commercially available under the name of BARIAS (manufactured by Mitsui Chemicals, Inc.).

[0123] In addition, examples of the above resin include SBR resins.

[0124] The content ratio of the above resin is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more with respect to 100% by mass of the total solid content of the intermediate layer 5. Also, the content ratio of the above resin may be 99% by mass or less, or may be 95% by mass or less with respect to 100% by mass of the total solid content of the intermediate layer 5.

[0125] The content ratio of the resin having the above water-soluble portion is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 90% by mass or more, based on 100% by mass of the total amount of the resin in the intermediate layer 5. It may also be 100% by mass. When the content ratio is within the above range, the barrier property of the intermediate layer 5 can be further improved, and the print storage property such as moisture and heat resistance can be further improved. Also, the content ratio of the core-shell type resin is preferably within the above range with respect to 100% by mass of the total amount of the above resin in the intermediate layer 5.

[0126] Examples of the above crosslinking agent include organic crosslinking agents such as cationic crosslinking agents and non-cationic crosslinking agents; inorganic crosslinking agents such as zirconium carbonate. Examples of the above cationic crosslinking agent include epichlorohydrin-based resins such as polyamide epichlorohydrin resin, polyamine epichlorohydrin resin, and polyamide polyamine epichlorohydrin resin. Examples of the above non-cationic crosslinking agent include oxazoline-based compounds such as oxazoline group-containing polymers and oxazoline group-containing low molecules. The above crosslinking agent is preferably a cationic crosslinking agent, and among them, polyamide epichlorohydrin resin is more preferable. These crosslinking agents can be used alone or in combination of two or more.

[0127] The content ratio of the above crosslinking agent is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, based on 100% by mass of the total solid content of the intermediate layer 5. Also, the content ratio of the above crosslinking agent is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 25% by mass or less, based on 100% by mass of the total solid content of the intermediate layer 5. When the content ratio is within the above range, an appropriate crosslinked structure can be formed, the barrier property of the intermediate layer 5 can be further improved, and the print storage property such as moisture and heat resistance can be further improved.

[0128] The coating amount (dry mass) of the intermediate layer 5 is, for example, 0.3 g / m 2 ~10 g / m 2 is preferable, and more preferably 1.0 g / m 2 ~4.0 g / m2 It is so. When the coating amount is within the above range, the barrier property of the obtained information recording medium 1 for laser marking can be made more appropriate, and the print storage property such as moisture and heat resistance can be further improved.

[0129] (Laminating layer) The laminating layer 6 is a layer for the purpose of enhancing the adhesion between the color developing layer 4 or the intermediate layer 5 and the second base material 7. The laminating layer 6 may not be provided if not necessary. In that case, for example, after coating the color developing layer 4 on the first base material 2, the second base material 7 can be laminated by bonding it before the color developing layer 4 is completely dried and then completely drying the color developing layer 4. From the viewpoint of improving the manufacturing efficiency, the information recording medium 1 for laser marking of the present embodiment preferably includes the laminating layer 6. The material for forming the laminating layer 6 is not particularly limited, and for example, known or commonly used laminating adhesives, adhesives, thermoplastic resins, hot melts, water-based adhesives, etc. can be used. Further, the laminating layer 6 may contain other components.

[0130] Examples of the above laminating adhesive include dry laminating adhesives such as urethane type, ether type, ester type, and epoxy type; non-solvent laminating adhesives such as urethane type, ether type, ester type, epoxy type, and isocyanate type. The above laminating adhesive may be of one-component type or two-component type. The above laminating adhesive may be of aliphatic type or aromatic type. Among them, from the viewpoint of excellent adhesive strength, a urethane type laminating adhesive is preferable, a urethane type dry laminating adhesive is more preferable, and a two-component type urethane type dry laminating adhesive is even more preferable. Also, from the viewpoint of environmental compatibility, an isocyanate type non-solvent laminating adhesive is preferable. The above two-component type laminating adhesive is used by mixing a main agent and a curing agent, and as the curing agent, known or commonly used curing agents such as isocyanate type curing agents can be used. The above laminating adhesive can be used alone or in combination of two or more.

[0131] The above-mentioned adhesive includes, for example, acrylic adhesives, rubber adhesives (natural rubber-based, synthetic rubber-based, mixed systems thereof, etc.), silicone adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, fluorine adhesives, and the like. Among them, acrylic adhesives are preferred from the viewpoints of excellent adhesion and transparency. The above-mentioned adhesive can be used alone or in combination of two or more kinds.

[0132] The coating amount (dry mass) of the laminate layer 6 is, for example, 0.3 g / m 2 ~50 g / m 2 is preferable, and more preferably 0.5 g / m 2 ~40 g / m 2 is. When the coating amount is within the above range, the adhesion between layers becomes more appropriate, and delamination between layers can be more suppressed.

[0133] (Other layers) The above-mentioned adhesive layer may be provided on the surface of the first base material 2 opposite to the coloring layer 4, or may be provided on the surface of the second base material 7 opposite to the coloring layer 4. From the viewpoint of making better use of the design property of the second base material 7, it is preferable that the above-mentioned adhesive layer is provided on the surface of the first base material 2 opposite to the coloring layer 4. By providing such an adhesive layer, the information recording body for laser marking of the present invention can be used for label applications. The above-mentioned adhesive layer can be mainly formed by an adhesive. The above-mentioned adhesive is not particularly limited, and examples thereof include the same ones as those exemplified in the item of the laminate layer. The above-mentioned adhesive layer may further contain other components as necessary.

[0134] The back coat layer may be provided on the surface of the first base material 2 opposite to the color developing layer 4, or may be provided on the surface of the second base material 7 opposite to the color developing layer 4. From the viewpoint of making better use of the design property of the second base material 7, it is preferable that the back coat layer is provided on the surface of the first base material 2 opposite to the color developing layer 4. Here, when an adhesive layer and a back coat layer are provided on the first base material 2, the adhesive layer can be laminated on the first base material 2 via the back coat layer, and when an adhesive layer and a back coat layer are provided on the second base material 7, the adhesive layer can be laminated on the second base material 7 via the back coat layer. By providing such a back coat layer, curling of the information recording body for laser marking can be further suppressed. The back coat layer can be mainly formed of a resin. The resin is not particularly limited, and examples thereof include the same ones as those exemplified in the items of the anchor layer and the intermediate layer. The back coat layer may further contain other components as necessary, and examples of the other components include a crosslinking agent, a surfactant, a preservative, and the like. The crosslinking agent is, for example, the same as those exemplified in the item of the intermediate layer.

[0135] [Laser Marking Method] The information recording body 1 for laser marking according to the present embodiment can be colored by irradiation with laser light. The laser light is not particularly limited, and examples thereof include carbon dioxide laser light, YAG laser light, YVO 4 Infrared laser light such as laser light; Visible light laser light such as green laser light; Ultraviolet laser light such as excimer laser light and THG laser light. Among them, the laser light is preferably ultraviolet laser light having a wavelength exceeding 351 nm and 400 nm or less, more preferably ultraviolet laser light having a wavelength exceeding 353 nm and 390 nm or less, further preferably ultraviolet laser light having a wavelength exceeding 353 nm and 360 nm or less, and particularly preferably THG laser light. When such laser light is used as a light source, better color developability can be obtained.

[0136] The information recording body 1 for laser marking according to this embodiment develops color based on, for example, the reaction between a leuco dye contained in the color developing layer 4 and a developer. Therefore, it can print more clearly as compared with color development based on phenomena such as scraping, gasifying, or carbonizing an object in conventional laser marking. Also, in the case of the laminated structure of this embodiment, since the first base material 2 and / or the second base material 7 protect the coating layer such as the color developing layer 4, dust generation during laser light irradiation can be suppressed, and contamination of the working environment can be further suppressed.

[0137] The information recording body 1 for laser marking according to this embodiment may be developed by irradiating the first base material 2 with laser light, or may be developed by irradiating the second base material 7 with laser light. Among them, it is preferable to develop the information recording body 1 for laser marking according to this embodiment by irradiating the first base material 2 with laser light. At this time, the first base material 2 is preferably a layer that transmits ultraviolet rays, and more preferably a layer that transmits ultraviolet rays and has smooth surfaces on both sides. Since the second base material 7 has an uneven shape on at least one surface, when laser light is irradiated, the laser light may be scattered or absorbed due to the uneven shape and material, and the transmittance of the laser light may decrease. Therefore, by irradiating the first base material 2 with laser light, the transmittance of the laser light can be further improved, and the color developability can be further improved.

[0138] [Manufacturing method of information recording body for laser marking] The manufacturing method of the information recording body for laser marking of the present invention is not particularly limited, and it can be manufactured by a known or commonly used method. For example, a coating liquid for the color developing layer is prepared by dispersing the material contained in the color developing layer 4 in a solvent such as water, this is coated on the smooth surface of the first base material 2, and before the coating liquid is completely dried, the second base material 7 is bonded and laminated so that the surface having the uneven shape of the second base material 7 is located on the side opposite to the color developing layer 4, whereby the information recording body 1 for laser marking in FIG. 1 can be obtained.

[0139] (Preparation process) The method for preparing the coating liquid for the color developing layer is not particularly limited. For example, it can be prepared by previously dispersing all the materials in the same solvent. Further, a dye and a developer that react with each other may be prepared as separate dispersions and then mixed to obtain the coating liquid for the color developing layer. At that time, other components may be added to either the dispersion containing the dye or the dispersion containing the developer, or to both. Examples of the method for preparing the coating liquid for the color developing layer include crushing treatments using stirring, ultrasonic treatment, ball mill, bead mill, sand mill, high-pressure homogenizer, etc. These methods can be used alone or in combination of two or more kinds.

[0140] (Coating step) The method for coating the coating liquid for the color developing layer is not particularly limited. For example, there are methods such as directly coating on a substrate, or coating on a release liner or the like and then transferring it to a substrate. Examples of the coating method include air knife coating, bar blade coating, pure blade coating, rod blade coating, short dwell coating, curtain coating, die coating, gravure coating, etc. Also, manual coating using a wire bar may be used. These methods can be used alone or in combination of two or more kinds.

[0141] (Drying step) The method for drying the coating liquid for the color developing layer is not particularly limited. For example, there are heating drying, normal temperature drying, vacuum drying, etc. These methods can be used alone or in combination of two or more kinds. By these methods, the color developing layer 4 can be formed.

[0142] When the information recording body for laser marking of the present invention includes layers other than the first substrate, the color developing layer, and the second substrate, the manufacturing method of the information recording body for laser marking can incorporate the above content. Also, when a laminate layer is provided, it can be laminated by known or conventional methods such as dry lamination method, non-solvent lamination method, extrusion lamination method, hot melt lamination method, etc.

[0143] As a method for manufacturing an information recording medium for laser marking according to an embodiment of the present invention, it is exemplified below with reference to FIG. 2. First, a coating liquid for an anchor layer is applied onto a first substrate 2 and dried to form an anchor layer 3. Next, a coating liquid for a color developing layer is applied onto the anchor layer 3 and dried to form a color developing layer 4. Next, a coating liquid for an intermediate layer is applied onto the color developing layer 4 and dried to form an intermediate layer 5. Next, a laminate layer 6 is formed on the intermediate layer 5. Then, the second substrate 7 and the laminate layer 6 are bonded directly so that the surface of the second substrate 7 having an uneven shape is located on the side opposite to the color developing layer 4, and they are laminated via the laminate layer 6, whereby the information recording medium 1 for laser marking can be obtained. Here, the coating liquid for the anchor layer and the coating liquid for the intermediate layer can be prepared by the same method as the preparation method of the coating liquid for the color developing layer. Further, the preparation method, the coating method, and the drying method are not particularly limited, and the methods listed above can be used. Further, the method of laminating via the laminate layer 6 is not particularly limited, and a known or conventional method can be applied according to the material of the laminate layer 6. For example, bonding by a dry lamination method using a dry lamination adhesive, bonding by a non-solvent lamination method using a non-solvent lamination adhesive, bonding by a hot melt lamination method using a hot melt adhesive, and bonding by an extrusion lamination method using a thermoplastic resin can be applied. When the above extrusion lamination method is used, a known or conventional anchor coating agent for extrusion lamination can also be used as an auxiliary agent. Further, when an adhesive is used as the material of the laminate layer 6, it can be bonded by applying pressure with or without heating.

[0144] The method for forming each of the above layers is not particularly limited. For example, multi-layer simultaneous coating may be performed using a curtain coater or the like, or they may be formed individually and sequentially. Further, some layers may be coated simultaneously and some layers may be formed individually and sequentially.

Example

[0145] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples at all.

[0146] Example 1 (Production of Information Recording Medium for Laser Marking) <Anchor layer> Using water as a solvent, a styrene acrylic resin with a solid content concentration of 38% by mass was applied and dried on the surface of a resin film (material: polypropylene, thickness: 30 μm) as the first substrate by a conventional method, so that the coating amount was 0.9 g / m 2 (dry mass) of the anchor layer was formed.

[0147] <Color developing layer> As a dye, 17.4% by mass of 3-dibutylamino-6-methyl-7-anilinofluoran, as a color developer, 26.8% by mass of N,N'-di-[3-(p-toluenesulfonyloxy)phenyl]urea, as a filler, 10.0% by mass of kaolin (water-dispersed product), as a binder, 33.1% by mass of styrene butadiene latex (SBR), as a lubricant, 1.5% by mass of polystyrene, as a dispersant, 9.1% by mass of an acrylic resin, as a crosslinking agent, 2.0% by mass of a polyamide epichlorohydrin resin, and water as a solvent were contained to prepare a coating liquid for the color developing layer (solid content concentration: 21% by mass) by a conventional method. The above coating liquid for the color developing layer was applied and dried on the surface of the above anchor layer by a conventional method, so that the coating amount was 4.5 g / m 2 (dry mass) of the color developing layer was formed. Note that the numerical values of the above respective materials indicate the mass ratio of each material with respect to 100% by mass of the color developing layer (dry state).

[0148] <Intermediate layer> As a resin, 85.0% by mass of a core-shell type acrylic resin, as a crosslinking agent, 15.0% by mass of a polyamide epichlorohydrin resin, and water as a solvent were contained to prepare a coating liquid for the intermediate layer (solid content concentration: 18.5% by mass) by a conventional method. The above coating liquid for the intermediate layer was applied and dried on the surface of the above color developing layer by a conventional method, so that the coating amount was 1.9 g / m 2An intermediate layer of (dry mass) was formed. The numerical values of the above materials indicate the mass ratio of each material with respect to 100% by mass of the intermediate layer (dry state).

[0149] <Laminated layer> A urethane-type adhesive for dry lamination containing ethyl acetate as a solvent and having a solid content concentration of 22% by mass (main agent: 93.7% by mass, curing agent: 6.3% by mass) was applied to the surface of the above intermediate layer by a conventional method to form a laminated layer. Thus, a laminate composed of [resin film (first substrate) / anchor layer / color-developing layer / intermediate layer / laminated layer] was produced.

[0150] Next, the laminated layer of the above laminate and a substrate A as the second substrate were dry laminated so as to be in direct contact (dry lamination method). The above substrate A is a non-woven fabric having uneven shapes on both sides (manufactured by Sanwa Shokai Co., Ltd., product name: long fiber wet non-woven fabric, opacity: 23.2%, Sa: 32.9 μm, Spc: 3418 mm -1 , Sdr: 8.75) was used. In this way, an information recording body for laser marking of Example 1 composed of [resin film (first substrate) / anchor layer / color-developing layer / intermediate layer / laminated layer / substrate A (second substrate)] was produced. The numerical values of the above materials indicate the mass ratio of each material with respect to 100% by mass of the laminated layer (dry state). The opacity of the above second substrate was measured by a method according to JIS P8149:2000 using a photo-voltaic type reflection densitometer (manufactured by Tokyo Denshoku Co., Ltd., apparatus name: TC-6DS / A). Also, the Sa, Spc, and Sdr of the above second substrate were all measured from the surface opposite to the color-developing layer by a method conforming to ISO25178 using a shape analysis laser microscope (manufactured by Keyence Corporation, apparatus name: VK-X1000).

[0151] Examples 2 to 5 (Production of Information Recording Body for Laser Marking) Instead of using Substrate A as the second substrate, as shown in Table 2, Example 2 used Substrate B (opacity: 46.8%), Example 3 used Substrate C (opacity: 49.4%), Example 4 used Substrate D (opacity: 50.2%), and Example 5 used Substrate E (opacity: 51.5%). Except for this, laser marking information recording media of Examples 2 to 5 were produced in the same manner as in Example 1. Here, the above Substrates B to E are all long fiber wet non-woven fabrics or special Japanese papers available from Sanwa Shokai Co., Ltd., and those having uneven shapes on both sides were used.

[0152] <Evaluation> The following evaluations were performed on the laser marking information recording media produced in the examples. The results are shown in Tables 1 and 2.

[0153] (1) Optical density of the printed part by THG laser For the laser marking information recording medium obtained in Example 1, printing was performed using a UV laser printer manufactured by Keyence Corporation with the operating speed set to any one of 1000 mm / sec, 1300 mm / sec, 1600 mm / sec, 1900 mm / sec, 2200 mm / sec, or 2500 mm / sec. Next, the optical density (OD value) of the developed printed part was measured from the second substrate side using a spectrophotometer (manufactured by Videojet Exalite Co., Ltd., device name: X-rite eXact), and the results are shown in Table 1. In this measurement, the frequency of the UV laser printer was 55 Hz and the laser power was 50%. During printing, mirror characters were printed by irradiating laser light on the first substrate side of the above information recording medium. Note that the above UV laser printer is a printing device with a laser light wavelength of 355 nm and using a THG laser as the light source.

[0154]

Table 1

[0155] (2) Suitability for barcode reading For the information recording bodies for laser marking obtained in Examples 2 to 5, a calibration barcode was printed, and an attempt was made to read the barcode by holding a barcode reader (manufactured by Welcome Design Co., Ltd., device name: USBee 1000A) from the second substrate side. Table 2 shows the results of evaluating the barcode reading suitability at this time based on the following criteria. ○: The barcode could be read in one attempt. △: The barcode could be read once in several attempts. ×: The barcode could not be read.

[0156]

Table 2

[0157] In each of the examples, although the information recording body included a second substrate having an uneven shape on at least one surface, printing could be performed with good printing quality. Also, as shown in Table 1, the information recording body for laser marking of Example 1 could be printed at a wide range of operating speeds by irradiating the first substrate with laser light.

[0158] Moreover, since each of the examples included a second substrate excellent in transparency and texture, they were excellent in design. Furthermore, since each of the second substrates had transparency, the viewer could clearly visually recognize the printed portion through the second substrate.

[0159] Also, at this time, since printing was possible without generating dust or damaging the first substrate, it was confirmed that the information recording body for laser marking of Example 1 was excellent in printing suitability with a THG laser (UV laser printer).

[0160] Also, as shown in Table 2, when the opacity of the second substrate was 50.2% or less, the barcode could be read and the barcode readability was good (Examples 2 to 4). Among them, when the opacity of the second substrate was 46.8%, it was possible to read the barcode by simply passing the barcode reader over it once, and the barcode readability was particularly excellent (Example 2). On the other hand, when the opacity of the second substrate was 51.5%, it was impossible to read the barcode even when the barcode reader was repeatedly passed over it (Example 5). From the above, it was confirmed that by using a second substrate with an opacity below a certain level, not only can the printing be easily visually recognized through the second substrate, but also the barcode can be accurately read.

[0161] Hereinafter, variations of the invention according to the present disclosure will be described. [Appendix 1] An information recording body in which a first substrate, a color developing layer, and a second substrate are laminated in this order, The first substrate and / or the second substrate is a layer that transmits ultraviolet light, The second substrate is an information recording body for laser marking having an uneven shape on at least one surface. [Appendix 2] The information recording body for laser marking according to Appendix 1, wherein the second substrate is at least one selected from the group consisting of Japanese paper, non-woven fabric, and a resin film having an uneven shape on at least one surface. [Appendix 3] The information recording body for laser marking according to Appendix 1 or 2, wherein the second substrate is Japanese paper or non-woven fabric. [Appendix 4] The information recording body for laser marking according to any one of Appendices 1 to 3, wherein the surface having the uneven shape of the second substrate is provided on the side opposite to the color developing layer. [Appendix 5] The information recording body for laser marking according to any one of Appendices 1 to 4, wherein the opacity of the second substrate is 51% or less. [Appendix 6] The information recording body for laser marking according to any one of Appendices 1 to 5, wherein the color developing layer contains a leuco dye and a developer. [Appendix 7] The information recording body for laser marking according to Appendix 6, wherein the developer contains a non-phenolic developer. [Appendix 8] The non-phenolic color former-containing laser marking information recording medium according to Appendix 7, wherein the non-phenolic color former contains at least the compound represented by the above formula (1) and / or the compound represented by the above formula (2). [Appendix 9] The non-phenolic color former-containing laser marking information recording medium according to Appendix 7 or 8, wherein the non-phenolic color former contains at least the compound represented by the above formula (1). [Appendix 10] The laser marking information recording medium according to any one of Appendices 1 to 9, wherein an intermediate layer is further provided between the color developing layer and the second base material. [Appendix 11] The laser marking information recording medium according to Appendix 10, wherein the intermediate layer contains a resin having a water-soluble portion and / or a cross-linking agent. [Appendix 12] The laser marking information recording medium according to Appendix 10 or 11, wherein the intermediate layer contains a resin having a water-soluble portion and a cross-linking agent. [Appendix 13] The laser marking information recording medium according to Appendix 11 or 12, wherein the resin having a water-soluble portion is a core-shell type resin having at least a carboxy group as the water-soluble portion. [Appendix 14] The laser marking information recording medium according to any one of Appendices 1 to 13, wherein the color-developing portion in the color developing layer is visible through the second base material. [Appendix 15] The laser marking information recording medium according to any one of Appendices 1 to 14, wherein the first base material is a layer that transmits ultraviolet rays. [Appendix 16] The laser marking information recording medium according to any one of Appendices 1 to 15, which can be colored by irradiation with ultraviolet laser light. [Appendix 17] The laser marking information recording medium according to any one of Appendices 1 to 16, wherein the first base material is a resin film. [Appendix 18] The laser marking information recording medium according to any one of Appendices 1 to 17, wherein the haze of the first base material is 30% or less. [Appendix 19] The laser marking information recording medium according to any one of Appendices 1 to 18, wherein the thickness of the first base material is 15 μm or more. [Appended Note 20] The laser marking information recording medium according to any one of Appended Notes 1 to 19, wherein the first base material is located on one end face of the laser marking information recording medium, and the second base material is located on the other end face of the laser marking information recording medium.

Explanation of Signs

[0162] 1 Laser marking information recording medium 2 First base material 3 Anchor layer 4 Color developing layer 5 Intermediate layer 6 Laminated layer 7 Second base material

Claims

1. This is an information recording body in which a first substrate, a color-developing layer, an intermediate layer, and a second substrate are stacked in this order. The first substrate and / or the second substrate is a layer that transmits ultraviolet light, The color-developing layer comprises a leuco dye and a color developer. The second substrate is an information recording body for laser marking, having an uneven shape on at least one surface.

2. The laser marking information recording body according to claim 1, wherein the second substrate is at least one selected from the group consisting of Japanese paper, nonwoven fabric, and resin film having an uneven shape on at least one surface.

3. The laser marking information recording body according to claim 1 or 2, wherein the surface having the uneven shape of the second substrate is provided on the side opposite to the color-developing layer.

4. The information recording body for laser marking according to claim 1 or 2, wherein the opacity of the second substrate is 51% or less.

5. The information recording body for laser marking according to claim 1 or 2, wherein the color developer comprises a non-phenolic color developer.

6. The laser marking information recorder according to claim 5, wherein the non-phenolic color developer comprises at least a compound represented by the following formula (1) and / or a compound represented by the following formula (2). 【Chemistry 1】 (In formula (1), R １ is a hydrocarbon group having 1 to 12 carbon atoms, which may have substituents, and a plurality of R １ They may be the same or different. A １ It is a hydrocarbon group having 1 to 4 carbon atoms, and multiple A １ (m may be the same or different. m represents an integer from 0 to 4, and multiple m values ​​may be the same or different.) 【Chemistry 2】 (Each symbol in formula (2) is the same as in formula (1) above.)

7. The information recording body for laser marking according to claim 6, wherein the non-phenolic color developer comprises at least a compound represented by formula (1).

8. The information recording body for laser marking according to claim 1 or 2, wherein the intermediate layer comprises a resin having a water-soluble portion and / or a crosslinking agent.

9. The information recording body for laser marking according to claim 1 or 2, wherein the colored portion in the colored layer is visible through the second substrate.

10. The information recording body for laser marking according to claim 1 or 2, wherein the first substrate is a layer that transmits ultraviolet light.

11. The laser marking information recording body according to claim 1 or 2, which can produce color by irradiation with ultraviolet laser light.

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