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JP-7855366-B2 - Thermal recording device

JP7855366B2JP 7855366 B2JP7855366 B2JP 7855366B2JP-7855366-B2

Inventors

  • 平井 健二
  • 登坂 昌也
  • 越 達朗
  • 緑川 佳美

Assignees

  • 日本製紙株式会社

Dates

Publication Date
20260508
Application Date
20220228

Claims (10)

  1. A thermal recording body having a thermal recording layer on a support containing a colorless or pale-colored electron-donating leuco dye and an electron-accepting color developer, The thermal recording layer contains, as a metal chelate-type coloring component, iron stearate and the following general formula (Chemical Formula 1) (In the formula, R is an alkyl group having 18 to 35 carbon atoms) The compound contains a polyvalent hydroxyaromatic compound represented by (wherein R a represents an alkyl group having 18 to 35 carbon atoms), -X- represents -CH2- , -CO2- , -CO-, -O-, -CONH-, -CONRb- (wherein R b represents an alkyl group having 18 to 35 carbon atoms), -SO2- , -SO3- , or -SO2NH- , and p represents an integer of 2 or 3), The electron-accepting color developer contains at least one urea compound represented by the following general formula (Chemical Formula 3) , A thermal recording medium in which the total content (solid content) of the urea compound relative to all of the electron-accepting color developer is 80% by weight or more . (In the formula, Y represents -O- or -NH-, R1 represents a hydrogen atom or -SO2 - R3 , R3 represents a substituted or unsubstituted alkyl group, aralkyl group or aryl group, R2 represents a hydrogen atom or alkyl group, m is an integer from 0 to 2, and n is 0 or 1.)
  2. The thermal recording body according to claim 1, wherein the urea compound is selected from the group consisting of (1) to (3) below. (1) A first urea compound represented by the following general formula (Chemical Formula 4), (In the formula, R1 , R2 , R3 , and n are defined in the same way as above.) (2) A second urea compound represented by the following general formula (Chemical Formula 5), (In the formula, R2 is defined as above, and R4 to R8 may be the same or different, and represent a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, an alkoxy group, an aryloxy group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, a monoalkylamino group, a dialkylamino group, or an arylamino group, and m is defined as above.) (3) A third urea compound represented by the following formula (Chemical Formula 6) (In the formula, R2 , R4 to R8 are defined in the same way as above.)
  3. The thermal recording material according to claim 2, wherein the thermal recording layer contains at least two urea compounds selected from the group consisting of (1) to (3) above as an electron-accepting color developer, provided that not more than two compounds are selected from each of (1), (2), or (3).
  4. The thermal recording body according to claim 2 or 3, wherein the first urea compound is represented by the following general formula (Chemical Formula 7). (In the formula, R2 is defined as above, and R3 may be the same or different group represented by the formula (Chemical Formula 14) below, and the position of R3 - SO3 -O- in the benzene ring of the general formula (Chemical Formula 7) may be the same or different, and is the 3rd, 4th, or 5th position.) (In the formula, R4 to R8 may be the same or different, and represent a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, an alkoxy group, an aryloxy group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, a monoalkylamino group, a dialkylamino group, or an arylamino group.)
  5. The thermal recording body according to claim 4, wherein the first urea compound is represented by the following general formula (Chemical Formula 8). (In the formula, R9 may be the same or different, and each represents an alkyl group or an alkoxy group, and o represents an integer from 0 to 3.)
  6. The thermal recording body according to claim 5, wherein in the first urea compound, R9 represents an alkyl group having 1 to 4 carbon atoms, o represents an integer from 0 to 1, and the position of R9 in the benzene ring is at position 4.
  7. The thermal recording body according to any one of claims 2 to 6, wherein the second urea compound is represented by the following general formula (Chemical Formula 9) or the following general formula (Chemical Formula 10).
  8. The thermal recording body according to any one of claims 2 to 7, wherein the third urea compound is N-[2-(3-phenylureido)phenyl]benzenesulfonamide.
  9. A thermal recording body according to any one of claims 1 to 8, wherein the content (solid content) of the urea compound in the thermal recording layer is 1.0 to 70.0% by weight.
  10. The thermal recording body according to any one of claims 2 to 9, wherein the thermal recording layer contains a color developer other than the first urea compound, the second urea compound, and the third urea compound, and the total content (solid content) of the first urea compound, the second urea compound, and the third urea compound relative to the total color developer contained in the thermal recording layer is 90% by weight or more.

Description

This invention relates to a thermal recording material with excellent solvent resistance. A thermal recording medium generally has a thermal recording layer consisting of a colorless or pale electron-donating leuco dye (hereinafter sometimes simply referred to as "leuco dye") and an electron-accepting developer (hereinafter sometimes simply referred to as "developer"; the color-developing component containing these leuco dyes and developers is also simply referred to as "leuco dye-type color-developing component"), a binder, a filler, a sensitivity enhancer, a lubricant, and other auxiliary agents, and is an information recording medium that obtains recorded information (color-developed information) by heat from a thermal head, hot stamp, thermal pen, laser light, etc. Thermal recording media are used in a wide range of applications, including measuring recorders, computer terminal printers, fax machines, automatic ticket vending machines, and barcode labels. However, with the diversification and increased performance of recording devices, the required quality of thermal recording media has also become more stringent. For example, with the increase in recording speed, it is necessary to obtain high-density and clear recorded information even with minute amounts of thermal energy. At the same time, thermal recording media with excellent preservation properties such as light resistance, heat resistance, water resistance, oil resistance, and plasticizer resistance are required. Furthermore, the use of adding additional information to the opposite side (back side) of the thermal recording layer with stamps or pens has also expanded. Furthermore, thermal recording media that utilize the color reaction between leuco dyes and color developers have the problem that the recorded information fades over time. To address this problem of faded recorded information, thermal recording media containing a metal chelate-type color component consisting of an electron donor and an electron acceptor have been disclosed (Patent Documents 1 and 2). Furthermore, by using a combination of two specific color developers, thermal recording materials with improved water resistance, plasticizer resistance in the image area, and heat resistance in the blank area have been disclosed (Patent Document 3, etc.), as well as urea compounds as color developers to improve required performance such as color density, whiteness, preservation of the printed area, and oil resistance of thermal recording materials (Patent Documents 4, 5, etc.). Japanese Patent Publication No. 06-155915Japanese Patent Publication No. 2010-115836Japanese Patent Publication No. 2015-80852Japanese Patent Publication No. 2020-066148International Public Release WO2021/095751 The thermal recording body of the present invention is a thermal recording body having a thermal recording layer on a support, and a protective layer may be provided on the thermal recording layer, an undercoat layer between the support and the thermal recording layer, a backcoat layer on the side of the support opposite to the thermal recording layer, and so on. The thermal recording layer of the present invention mainly contains a colorless or pale electron-donating leuco dye and an electron-accepting developer (all leuco dye type color-developing components), and further contains a metal chelate type color-developing component mainly containing an electron acceptor and an electron donor. In the thermal recording material of the present invention, iron stearate is used as the higher fatty acid metal salt contained as an electron acceptor among the metal chelate-type color-developing components used in the thermal recording layer. Compared to other higher fatty acid metal salts commonly used as electron acceptors in metal chelate-type color-developing components, the present invention, which uses iron stearate, offers advantages such as superior heat resistance and resistance to yellowing in non-printed areas. In the thermal recording material of the present invention, the polyvalent hydroxyaromatic compound contained as an electron donor among the metal chelate-type color-developing components used in the thermal recording layer is represented by the following general formula (Chemical Formula 1). (In the formula, R is an alkyl group having 18 to 35 carbon atoms) (In the formula, R a represents an alkyl group having 18 to 35 carbon atoms.) -X- represents -CH2- , -CO2- , -CO-, -O-, -CONH-, -CONRb- (In the formula, R b represents an alkyl group having 18 to 35 carbon atoms.), -SO2- , -SO3- , or -SO2NH- , and p represents an integer of 2 or 3.) In the thermal recording material of the present invention, the polyvalent hydroxyaromatic compound, in other words, the polyvalent phenol derivative, contained in the thermal recording layer as an electron donor, needs to avoid reaction with electron acceptors and improve solvent resistance and dispersion stability when dispersed in an aqueous or solvent-based