Search

JP-7855958-B2 - Thermal recording materials

JP7855958B2JP 7855958 B2JP7855958 B2JP 7855958B2JP-7855958-B2

Inventors

  • 秋元 真也
  • 青山 茂生

Assignees

  • 王子ホールディングス株式会社

Dates

Publication Date
20260511
Application Date
20220726

Claims (7)

  1. A thermal recording material comprising a support including at least one colored surface, and a light-scattering layer disposed thereon, wherein the light-scattering layer contains non-hollow polymer particles and a clearing agent, the proportion of the non-hollow polymer particles being 25 to 60% by mass of the total solid content of the light-scattering layer, the proportion of the clearing agent being 10 to 40% by mass of the total solid content of the light-scattering layer, and the light-scattering layer substantially free of dye precursors and color developers . A thermal recording material wherein the clearing agent contains at least one selected from the group consisting of stearic acid amide, palmitic acid amide, aromatic oxalic acid ester, aromatic ethylene glycol ether, ethylene-bis-stearic acid amide, 1,2-diphenyloxyethane, 1,2-di(3-methylphenoxy)ethane, dibenzyl oxalate, dibenzyl terephthalate, benzyl biphenyl, benzyl-2-naphthyl ether, diphenyl sulfone, m-terphenyl, p-benzyloxybenzyl benzoate, cyclohexanedimethanol benzoate, p-toluenesulfonamide, o-toluenesulfonamide, 2,6-diisopropylnaphthalene, 4,4-diisopropylbiphenyl, and erucic acid amide .
  2. The thermal recording material according to claim 1, wherein the clearing agent contains at least one selected from the group consisting of stearic acid amide and palmitic acid amide.
  3. The thermal recording material according to claim 1, wherein the clearing agent contains both stearic acid amide and palmitic acid amide.
  4. The thermal recording material according to any one of claims 1 to 3 , wherein the content of the non-hollow polymer particles is 30 to 50% by mass of the total solid content of the light scattering layer.
  5. The thermal recording material according to any one of claims 1 to 3 , wherein the content of the transparentizing agent is 20 to 35% by mass of the total solid content of the light scattering layer.
  6. The thermal recording material according to any one of claims 1 to 3 , wherein the average particle size of the polymer particles that do not have a hollow is 0.2 to 3.0 μm.
  7. The thermal recording material according to any one of claims 1 to 3 , wherein the refractive index of the polymer particles that do not have a hollow space is 1.55 to 1.65.

Description

This invention relates to a thermal recording material. Thermal recording materials that record colored images using a heating-induced color reaction between a colorless or pale-colored dye precursor and phenols or organic acids are widely used. Because such thermal recording materials form colored images simply by heating, they offer advantages such as compact recording devices, easy maintenance, and low noise generation. Therefore, thermal recording materials are widely used as information recording materials in various applications, including label printers, automatic ticket vending machines, CD/ATM machines, order slip output machines in restaurants, and data output machines for scientific research equipment. Besides thermal recording materials that utilize the color development reaction between dye precursors and color developers, there are other thermal recording materials, such as the one reported in Patent Document 1. Patent Document 1 reports a recording material comprising a) a support including at least one colored surface; and b) a layer disposed thereon, wherein the layer contains polymer particles having a core/shell structure and an opacity reducing agent having a melting point of 45°C to 200°C, in an amount of 1% to 90% by weight based on the weight of the polymer particles, the particles having an outer first polymer shell with a calculated Tg of 40°C to 130°C, and the particles containing at least one void when dry. In this type of thermal recording material, the colored surface is concealed by an opaque layer. Heat causes an opacity-reducing agent to melt, making the layer on the colored surface transparent and allowing the colored surface to be seen, thus enabling printing. However, conventional thermal recording materials that substantially do not contain dye precursors and color developers have insufficient whiteness, color density, and printability, and there is room for improvement. Special table 2014-512290 publication In this specification, the expression "contains" includes the concepts of "contains," "consisting only of substance," and "consisting only of." In this specification, numerical ranges indicated using "~" refer to the range that includes the values before and after "~" as the lower and upper limits. The latex in this invention includes a gel or dried film state formed by drying the dispersion medium. Furthermore, in this invention, "average particle diameter" refers to the volume-based median diameter measured by laser diffraction. More simply, one may measure the particle diameter from individual particle images (SEM images) using an electron microscope and indicate the average value of 10 particles. The present invention relates to a thermal recording material comprising a support containing at least one colored surface and a light-scattering layer disposed thereon, wherein the light-scattering layer contains non-hollow polymer particles and a clearing agent, the content of the non-hollow polymer particles is 25 to 60% by mass of the total solid content of the light-scattering layer, the content of the clearing agent is 10 to 40% by mass of the total solid content of the light-scattering layer, and the light-scattering layer substantially does not contain a dye precursor or a color developer. [Support] The support in the present invention is not particularly limited in terms of type, shape, dimensions, etc., and can be appropriately selected and used from among, for example, high-quality paper (acidic paper, neutral paper), medium-quality paper, coated paper, art paper, cast-coated paper, glassine paper, resin-laminated paper, polyolefin-based synthetic paper, synthetic fiber paper, nonwoven fabric, synthetic resin film, and various transparent supports. In embodiments of the present invention, the support may have a colored surface on one side, or both sides may be colored. The color may be provided, for example, by a pigment, dye, or the inherent color of the support, and the support may be immersed in a coloring agent to provide a colored surface. The thickness of the support is not particularly limited, and is usually about 20 to 200 μm. The density of the support is also not particularly limited, but is preferably about 0.60 to 0.85 g/ cm³ . [Colored side] The thermal recording material of the present invention has at least one colored surface on the support. This makes it possible to print when the light scattering layer becomes transparent due to heat. The support may have a colored surface on one side, or on both sides. The colored surface only needs to have a sufficiently contrasting color density with respect to the light-scattering layer placed on it. The colored surface may have a uniform color density, a varying color density, or a patterned surface. The type of color of the colored surface is not particularly limited; any color is acceptable. The colored surface may be a colored layer formed on a support. The colored layer may contain dyes, pigments, ca