Thermosensitive recording body

Abstract

The objective of this invention is to provide a thermal recorder that exhibits excellent high-speed printability, as well as superior oil resistance, plasticizer resistance, and printability, among other properties required for thermal recorders. A thermal recorder comprises a base coating on a support, and a thermal recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on the base coating. The electron-accepting developer in the thermal recording layer contains a urea compound represented by the following general formula (Chemical Formula 1). The base coating contains 50-95% by weight of pigment (solid content) and 50% or more by weight of hollow plastic particles relative to the pigment (solid content). (Where X represents -O- or -NH-, R...) 1 Represents a hydrogen atom or -SO2-R 3 R 3 Indicates substituted or unsubstituted alkyl, aralkyl, or aryl groups, R 2 (This represents a hydrogen atom or an alkyl group, m represents an integer from 0 to 2, and n represents 0 or 1.)

Description

Technical Field

[0001] This invention relates to a thermal recorder that utilizes the color reaction between a colorless or light-colored electron-donating leuco dye (hereinafter also referred to as "leuco dye") and an electron-accepting color developer (hereinafter also referred to as "color developer"). The thermal recorder exhibits excellent high-speed printability, as well as excellent oil resistance, plasticizer resistance, and printability. Background Technology

[0002] Generally, thermal recorders are products obtained by coating a substrate such as paper, synthetic paper, film, or plastic with a coating solution containing colorless or light-colored leuco dyes and developers. The image is recorded through a transient chemical reaction caused by heating using a thermal printhead, thermal embossing, thermal pen, laser, or similar device. Thermal recorders are widely used as recording media in fax machines, computer terminal printers, automatic ticket vending machines, measuring recorders, and receipts in supermarkets and convenience stores.

[0003] In recent years, thermal recorders have been expanded to various applications such as tickets, receipts, labels, bank ATMs, gas and electricity meter readings, and transportation tickets. Therefore, it is believed that various properties are required, such as water resistance, plasticizer resistance of the image part, heat resistance of the white paper part, oil resistance, and preservation of the image part and white paper part under harsh conditions.

[0004] To address these requirements, patent documents have been disclosed regarding thermal recorders that improve water resistance, plasticizer resistance of the image section, and heat resistance of the white paper section by using two specific color developers in combination (Patent Document 1), and urea compounds that serve as color developers to improve the required performance of thermal recorders, such as color intensity, whiteness, and preservation of the printed section (Patent Documents 2 and 3).

[0005] In addition, as a method to improve the sensitivity and printing quality of thermal recorders, a base coating containing hollow particles has been proposed between the support and the thermal recording layer (Patent Documents 4, 5, etc.).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2015-80852

[0009] Patent Document 2: International Publication WO2019 / 044462

[0010] Patent Document 3: Japanese Patent Application Publication No. 2020-066148

[0011] Patent Document 4: Japanese Patent Application Publication No. 2020-152027

[0012] Patent Document 5: Japanese Patent 6782511 Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] Therefore, the purpose of this invention is to provide a thermal recorder that, among the various properties required for thermal recorders, exhibits excellent high-speed printability, as well as excellent oil resistance, plasticizer resistance, and printability.

[0015] Methods for solving problems

[0016] The inventors conducted in-depth research and found that by including a specific urea compound as a color developer in the thermal recording layer disposed on the support, and by providing a base layer between the support and the thermal recording layer, and by including a specific amount of hollow plastic particles in the base layer, the above-mentioned problems can be solved, thus completing the present invention.

[0017] That is, the present invention is a thermal recording medium, wherein a base coating is provided on a support, and a thermal recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting color developer is provided on the base coating. The thermal recording layer contains a urea compound represented by the following general formula (chemical formula 1) as the electron-accepting color developer. The base coating contains 50 to 95% by weight of pigment as solid component and contains 50% or more of plastic hollow particles as solid component relative to the pigment.

[0018] [Chemical Formula 1]

[0019]

[0020] (In the formula, X represents -O- or -NH-, R 1 Represents a hydrogen atom or -SO2-R 3 R 3 Indicates substituted or unsubstituted alkyl, aralkyl, or aryl groups, R 2 (This represents a hydrogen atom or an alkyl group, m represents an integer from 0 to 2, and n represents 0 or 1.)

[0021] Invention Effects

[0022] This invention provides a thermal recorder that not only has excellent color rendering properties but also good high-speed printability, thereby providing a thermal recorder with good oil resistance, plasticizer resistance, and printability. Detailed Implementation

[0023] The thermal recorder of the present invention has a thermal recording layer on a support, and an undercoat layer between the support layer and the thermal recording layer. The thermal recording layer contains a specific urea compound as an electron-accepting colorimetric agent, and the undercoat layer contains a specific amount of hollow plastic particles.

[0024] Hereinafter, various materials used in the thermal recording layer of the thermal recorder of the present invention are exemplified, but binders, crosslinking agents, pigments, etc., can also be used in the base layer and each coating layer provided as needed, without hindering the desired effect on the above-mentioned issues.

[0025] For the thermal recorder of the present invention, its thermal recording layer contains at least one urea compound represented by the above general formula (chemical formula 1) as a colorimetric agent. In the above general formula (chemical formula 1), R... 3 Preferably, it is a substituted or unsubstituted aryl group, more preferably a group represented by the following formula.

[0026] [Chemical Formula 11]

[0027]

[0028] (where R is in the formula) 4 ~R 8 (Optionally, the same or different groups may represent hydrogen atom, halogen atom, nitro group, amino group, alkyl group, alkoxy group, aryloxy group, alkyl carbonyloxy group, aryl carbonyloxy group, alkyl carbonylamino group, aryl carbonylamino group, alkyl sulfonylamino group, aryl sulfonylamino group, monoalkylamino group, dialkylamino group, or arylamino group.)

[0029] The urea compound is preferably selected from (1) to (3) below.

[0030] (1) The first urea compound represented by the following general formula (chemical formula 2),

[0031] [Chemical Formula 2]

[0032]

[0033] (where R is in the formula) 1 R 2 and R 3 Same as the definition described above.

[0034] (2) The second urea compound represented by the following general formula (chemical formula 3),

[0035] [Chemical Formula 3]

[0036]

[0037] (where R is in the formula) 2 And m is defined the same as above, R 4 ~R 8 (This will be explained later.)

[0038] (3) The third urea compound represented by the following formula (chemical formula 4),

[0039] [Chemical Formula 4]

[0040]

[0041] (where R is in the formula) 2 As defined above, R 4 ~R 8 (This will be explained later.)

[0042] Furthermore, the urea compound used in this invention is more preferably selected from at least two of the urea compounds represented in (1) to (3) above. However, in this case, the urea compound is not selected from more than two of (1), (2), or (3) respectively. That is, the at least two urea compounds are a combination of the first urea compound and the second urea compound, a combination of the first urea compound and the third urea compound, a combination of the second urea compound and the third urea compound, and a combination of the first urea compound to the third urea compound represented in (1) to (3).

[0043] The first urea compound used in this invention is represented by the following formula (Chemical Formula 2), preferably by the following formula (Chemical Formula 5).

[0044] [Chemical Formula 2]

[0045]

[0046] [Chemical Formula 5]

[0047]

[0048] In the general formula (chemical formula 2), R 1 Represents a hydrogen atom or -SO2-R 3 n represents 0 or 1, preferably 1.

[0049] In general formulas (chemical formula 2) and (chemical formula 5), ​​R 3 This indicates that the alkyl, aralkyl, or aryl group can be substituted or unsubstituted. The alkyl group is, for example, a straight-chain, branched, or alicyclic alkyl group, and preferably has 1 to 12 carbon atoms. The aralkyl group preferably has 7 to 12 carbon atoms, and the aryl group preferably has 6 to 12 carbon atoms. Furthermore, when they are substituted, the substituents are preferably alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, aryl groups having 6 to 12 carbon atoms, or halogen atoms. Additionally, multiple R... 3 Choose either the same or different.

[0050] R in the benzene ring of general formula (chemical formula 2) 1 The positions of -O- can be chosen to be the same or different, preferably 3, 4 or 5.

[0051] R in the benzene ring of general formula (chemical formula 2) and general formula (chemical formula 5)3 The positions of -SO2-O- can be chosen to be the same or different, preferably 3, 4 or 5.

[0052] Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopentyl, hexyl, cyclohexyl, 2-ethylhexyl, lauryl, etc.

[0053] Examples of such aralkyl groups include benzyl, 1-phenylethyl, 2-phenylethyl, 3-phenylpropyl, p-methylbenzyl, m-methylbenzyl, m-ethylbenzyl, p-ethylbenzyl, p-isopropylbenzyl, p-tert-butylbenzyl, p-methoxybenzyl, m-methoxybenzyl, o-methoxybenzyl, m-, p-dimethoxybenzyl, p-ethoxym-methoxybenzyl, p-phenylmethylbenzyl, p-cumylbenzyl, p-phenylbenzyl, o-phenylbenzyl, m-phenylbenzyl, p-tolylbenzyl, m-tolylbenzyl, o-tolylbenzyl, p-chlorobenzyl, and other unsubstituted or substituted aralkyl groups, alkoxy groups, aralkyl groups, aryl groups, or halogen atoms.

[0054] Examples of aryl groups include phenyl, p-tolyl, m-tolyl, o-tolyl, 2,5-dimethylphenyl, 2,4-dimethylphenyl, 3,5-dimethylphenyl, 2,3-dimethylphenyl, 3,4-dimethylphenyl, mesitylene, p-ethylphenyl, p-isopropylphenyl, p-tert-butylphenyl, p-methoxyphenyl, 3,4-dimethoxyphenyl, p-ethoxyphenyl, p-chlorophenyl, 1-naphthyl, 2-naphthyl, tert-butylated naphthyl, and other unsubstituted or substituted aryl groups, such as those substituted with alkyl, alkoxy, aralkyl, aryl, or halogen atoms.

[0055] R 2 The symbol represents a hydrogen atom or an alkyl group, preferably a hydrogen atom. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, etc.

[0056] R in the benzene ring of general formula (chemical formula 2) 2 The positions can be the same or different, preferably 3, 4 or 5.

[0057] The first urea compound of the present invention is further preferably a urea compound represented by the following general formula (Chemical Formula 6).

[0058] [Chemical Formula 6]

[0059]

[0060] In the general formula (Chemical Formula 6), R 9 It is an alkyl or alkoxy group, preferably an alkyl group, where o represents an integer from 0 to 3, preferably 0 to 2, and more preferably 0 to 1. The alkyl group has, for example, 1 to 12 carbon atoms, preferably 1 to 8, and more preferably 1 to 4.

[0061] R in the benzene ring of general formula (chemical formula 6) 9 The positions can be the same or different, preferably 3, 4 or 5, with 4 being the most preferred.

[0062] In addition, examples of the first urea compound of the present invention include N,N'-bis[3-(benzenesulfonyloxy)phenyl]urea, N,N'-bis-[3-(benzenesulfonyloxy)-4-methyl-phenyl]urea, N,N'-bis-[3-(benzenesulfonyloxy)-4-ethyl-phenyl]urea, N,N'-bis-[3-(benzenesulfonyloxy)-5-methyl-phenyl]urea, N,N'-bis-[3-(benzenesulfonyloxy)-4-propyl-phenyl]urea, N,N'-bis-[3-(o-toluenesulfonyloxy)phenyl]urea, N,N'-bis-[3-(m-toluenesulfonyloxy)phenyl]urea, and N,N'-bis-[3-(p-toluenesulfonyloxy)phenyl]urea. N,N'-di-[3-(p-toluenesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[3-(p-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(tris(toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(1-naphthalenesulfonyloxy)phenyl]urea, N,N'-di-[3-(2-naphthalenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-propylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-isopropylbenzenesulfonyloxy)phenyl]urea [3-(p-tert-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, N,N'-di-[3-(m-,p-dimethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-ethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-propoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-butoxybenzenesulfonyloxy)phenyl]urea, N N'-bis-[3-(p-cumylbenzylsulfonyloxy)phenyl]urea, N,N'-bis-[3-(p-cumylbenzylsulfonyloxy)phenyl]urea, N,N'-bis-[3-(o-phenylbenzylsulfonyloxy)phenyl]urea, N,N'-bis-[3-(p-phenylbenzylsulfonyloxy)phenyl]urea, N,N'-bis-[3-(p-chlorobenzylsulfonyloxy)phenyl]urea, N,N'-bis-[4-(benzylsulfonyloxy)phenyl]urea, N,N'-bis-[4-(p-toluenesulfonyloxy)phenyl]urea, N,N'-bis-[3-(ethanesulfonyloxy)phenyl]urea, N,N'-bis-[3-(benzylsulfonyloxy)phenyl]urea, etc., but not limited to these.

[0063] The second urea compound used in this invention is represented by the following formula (Chemical Formula 3).

[0064] [Chemical Formula 3]

[0065]

[0066] In the general formula (chemical formula 3), R 2 R 4 ~R 8 Same definition as described above. In general formula (chemical formula 3), R 4 ~R 8 Preferably, it is a hydrogen atom, alkyl group, or alkoxy group. In particular, as R... 4 R 5 R 7 R 8 Hydrogen atoms are preferred as R 6 Preferably, it contains hydrogen atoms or alkyl groups. As R 6 Alkyl groups are particularly preferred.

[0067] The alkyl group (including alkyl carbonyloxy, alkyl carbonylamino, alkyl sulfonylamino, monoalkylamino, and dialkylamino groups containing alkyl groups) and aryl group (including aryloxy, aryl carbonyloxy, aryl carbonylamino, aryl sulfonylamino, and arylamino groups containing aryl groups) are defined in the same way as the alkyl and aryl groups in the above general formula (Chemical Formula 2).

[0068] The alkoxy group is, for example, a straight-chain, branched, or alicyclic alkoxy group, and preferably has 1 to 12 carbon atoms.

[0069] The -O-(CONH) in the benzene ring of general formula (chemical formula 3) m The -SO2-substituted phenyl group is preferably positioned at the 3, 4, or 5 position (the same applies in the following general formulas (Chemical Formula 7 and Chemical Formula 8)).

[0070] In the general formula (chemical formula 3), m represents an integer from 0 to 2, preferably an integer from 0 to 1.

[0071] As the second urea compound of the present invention, a urea compound represented by the following general formula (Chemical Formula 7) or the following general formula (Chemical Formula 8) is preferred.

[0072] [Chemical Formula 7]

[0073]

[0074] [Chemical Formula 8]

[0075]

[0076] The third urea compound used in this invention is represented by the following formula (Chemical Formula 4).

[0077] [Chemical Formula 4]

[0078]

[0079] In the general formula (chemical formula 4), R 2 R 4 ~R 8 Same as the definition described above.

[0080] As the third urea compound, N-[2-(3-phenylureo)phenyl]benzenesulfonamide is preferred. This compound is represented by the following formula and, for example, can be obtained from Nippon Soda Co., Ltd. under the trade name NKK1304.

[0081] [Chemical Formula 12]

[0082]

[0083] The content of urea compounds in the thermal recording layer of the present invention (solid component, in the case of multiple urea compounds, is the total amount) is 1.0 to 70.0% by weight, preferably 5.0 to 65.0% by weight, more preferably 10.0 to 60.0% by weight.

[0084] The content of the first urea compound in the thermal recording layer of the present invention is 1.0 to 50.0% by weight, preferably 5.0 to 40.0% by weight. Furthermore, the content of the second urea compound is 5.0 to 50.0% by weight, preferably 5.0 to 40.0% by weight. Furthermore, the content of the third urea compound is 5.0 to 50.0% by weight, preferably 5.0 to 40.0% by weight.

[0085] It should be noted that when the thermal recording layer of the present invention comprises a first urea compound and a second urea compound, the content of the second urea compound in the thermal recording layer is preferably 0.1 to 30.0 parts by weight, more preferably 0.5 to 25.0 parts by weight, further preferably 1.0 to 20.0 parts by weight, and particularly preferably 2.0 to 15.0 parts by weight, relative to 1.0 parts by weight of the first urea compound. Furthermore, when the thermal recording layer of the present invention comprises a first urea compound and a third urea compound, the content of the third urea compound in the thermal recording layer is preferably 0.1 to 30.0 parts by weight, more preferably 0.5 to 25.0 parts by weight, further preferably 1.0 to 20.0 parts by weight, and particularly preferably 2.0 to 15.0 parts by weight, relative to 1.0 parts by weight of the first urea compound. Furthermore, when the thermal recording layer of the present invention contains a second urea compound and a third urea compound, the content of the third urea compound in the thermal recording layer is preferably 0.1 to 30.0 parts by weight, more preferably 0.3 to 25.0 parts by weight, further preferably 0.5 to 20.0 parts by weight, and particularly preferably 0.7 to 15.0 parts by weight, relative to 1.0 parts by weight of the second urea compound.

[0086] The thermal recording layer of the present invention can use a colorimetric agent other than the compounds mentioned in the first to third paragraphs. Examples of such colorimetric agents include, for instance, inorganic acidic substances such as activated clay, palygorskite, colloidal silica, and aluminum silicate; 4,4'-isopropylidene diphenol; 1,1-bis(4-hydroxyphenyl)cyclohexane; 2,2-bis(4-hydroxyphenyl)-4-methylpentane; 4,4'-dihydroxydiphenyl sulfide; hydroquinone monobenzyl ether; benzyl 4-hydroxybenzoate; 4,4'-dihydroxydiphenyl sulfone; 2,4'-dihydroxydiphenyl sulfone; and 4-hydroxy-4'-isopropoxydiphenyl sulfone. Phenyl sulfone, 4-hydroxy-4'-n-propoxydiphenyl sulfone, bis(3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxyphenyl-4'-benzyloxyphenyl sulfone, 3,4-dihydroxyphenyl-4'-methylphenyl sulfone, 1-[4-(4-hydroxybenzenesulfonyl)phenoxy]-4-[4-(4-isopropoxybenzenesulfonyl)phenoxy]butane, the phenol condensation composition disclosed in Japanese Patent Application Publication No. 2003-154760, the aminobenzenesulfonamide derivative disclosed in Japanese Patent Application Publication No. 8-59603, bis(4-hydroxyphenylthioethoxy)methane, 1,5-Di(4-hydroxyphenylthio)-3-oxapentane, bis(p-hydroxyphenyl)acetic acid butyl ester, bis(p-hydroxyphenyl)acetic acid methyl ester, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,4-bis[α-methyl-α-(4'-hydroxyphenyl)ethyl]benzene, 1,3-bis[α-methyl-α-(4'-hydroxyphenyl)ethyl]benzene, di(4-hydroxy-3-methylphenyl)sulfide, 2,2'-thiobis(3-tert-octylphenol), 2,2'-thiobis(4-tert-octylphenol), as described in WO02 / 081229 or Japanese Patent Application Publication No. 2002-301873 Compounds, including thiourea compounds such as N,N'-di-m-chlorophenylthiourea, p-chlorobenzoic acid, stearyl gallate, bis[4-(n-octyloxycarbonylamino)zinc salicylate] dihydrate, 4-[2-(p-methoxyphenoxy)ethyloxy]salicylic acid, 4-[3-(p-toluenesulfonyl)propyloxy]salicylic acid, 5-[p-(2-p-methoxyphenoxyethoxy)cumyl]salicylic acid, and salts of these aromatic carboxylic acids with polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, and nickel, as well as antipyrine complexes of zinc thiocyanate, and complex zinc salts of p-formylbenzoic acid with other aromatic carboxylic acids. These colorimetric agents can be used alone or in mixtures of two or more.1-[4-(4-hydroxybenzenesulfonyl)phenoxy]-4-[4-(4-isopropoxybenzenesulfonyl)phenoxy]butane, for example, can be obtained as trade name JKY-214 manufactured by API Corporation. The phenol condensation composition disclosed in Japanese Patent Application Publication No. 2003-154760, for example, can be obtained as trade name JKY-224 manufactured by API Corporation. Furthermore, compounds disclosed in WO02 / 081229, etc., can be obtained as trade names NKK-395 and D-100 manufactured by Nippon Soda Co., Ltd. In addition, it may also contain metal chelate type coloring components such as higher fatty acid metal complex salts and polyhydroxy aromatic compounds disclosed in Japanese Patent Application Publication No. 10-258577.

[0087] When the thermal recording layer of the present invention contains a color developer other than the first urea compound to the third urea compound, the total content (solid component) of the first urea compound to the third urea compound used relative to all the color developers (including the aforementioned first urea compound to the third urea compound) contained in the thermal recording layer is preferably 50% by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more.

[0088] As the leuco dye used in this invention, any leuco dye known in the field of pressure-sensitive or thermal recording paper can be used without particular limitation. Preferred leuco dyes include triphenylmethane compounds, fluoran compounds, fluorene compounds, and divinyl compounds. Specific examples of representative colorless or light-colored dyes (dye precursors) are shown below. Furthermore, these dye precursors can be used alone or in mixtures of two or more.

[0089] <Triphenylmethane-based leuco dyes>

[0090] 3,3-Bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone) and 3,3-bis(p-dimethylaminophenyl)phthalide (also known as malachite green lactone).

[0091] <Fluorane leuco dyes>

[0092] 3-Diethylamino-6-methylfluorane, 3-Diethylamino-6-methyl-7-aniline fluorane, 3-Diethylamino-6-methyl-7-(o,p-dimethylaniline)fluorane, 3-Diethylamino-6-methyl-7-chlorofluorane, 3-Diethylamino-6-methyl-7-(m-trifluoromethylaniline)fluorane, 3-Diethylamino-6-methyl-7-(o-chloroaniline)fluorane, 3-Diethylamino-6-methyl-7-(p-chloroaniline)fluorane, 3-Diethylamino-6-methyl-7-(o-fluoroaniline)fluorane, 3-Diethylamino-6-methyl-7-(m-methylaniline)fluorane, 3-Diethylamino-6-methyl-7-n-octylaniline fluorane, 3-Diethylamino -6-Methyl-7-n-octylaminofluorane, 3-diethylamino-6-methyl-7-benzylaminofluorane, 3-diethylamino-6-methyl-7-dibenzylaminofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-6-chloro-7-aniline fluorane, 3-diethylamino-6-chloro-7-p-methylaniline fluorane, 3-diethylamino-6-ethoxyethyl-7-aniline fluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-(m-trifluoromethylaniline)fluorane, 3-diethylamino-7-(o-chloroaniline)fluorane, 3-diethylamino-7-(p-chloroaniline)fluorane, 3-diethylamino-7-(p-chloroaniline)fluorane, 3-diethylamino-7-(o-chloroaniline)fluorane, 3-Diethylamino-benzo[a]fluorane, 3-Diethylamino-benzo[c]fluorane, 3-Dibutylamino-6-methylfluorane, 3-Dibutylamino-6-methyl-7-aniline fluorane, 3-Dibutylamino-6-methyl-7-(o,p-dimethylaniline)fluorane, 3-Dibutylamino-6-methyl-7-(o-chloroaniline)fluorane, 3-Dibutylamino-6-methyl-7-(p-chloroaniline)fluorane, 3-Dibutylamino-6-methyl-7-(o-fluoroaniline)fluorane, 3-Dibutylamino-6-methyl-7-(m-trifluoromethylaniline)fluorane, 3-Dibutylamino-6-methyl-7-chlorofluorane, 3-Dibutylamino-6-methyl-7-chlorofluorane, 3-Dibutylamino-6- Ethoxyethyl-7-aniline fluorane, 3-dibutylamino-6-chloro-7-aniline fluorane, 3-dibutylamino-6-methyl-7-p-methylaniline fluorane, 3-dibutylamino-7-(o-chloroaniline) fluorane, 3-dibutylamino-7-(o-fluoroaniline) fluorane, 3-di-n-pentylamino-6-methyl-7-aniline fluorane, 3-di-n-pentylamino-6-methyl-7-(p-chloroaniline) fluorane, 3-di-n-pentylamino-7-(m-trifluoromethylaniline) fluorane, 3-di-n-pentylamino-6-chloro-7-aniline fluorane, 3-di-n-pentylamino-7-(p-chloroaniline) fluorane, 3-pyrrolidino-6-methyl-7-aniline fluorane,3-Piperidino-6-methyl-7-anilinofluorane, 3-(N-methyl-N-propylamino)-6-methyl-7-anilinofluorane, 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-xylmethylamino)-6-methyl-7-(p-chloroanilino)fluorane, 3-(N-ethyl-p-toluidine)-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-isopentylamino)-6-methyl-7 -Anilinefluorane, 3-(N-ethyl-N-isopentylamino)-6-chloro-7-anilinefluorane, 3-(N-ethyl-N-tetrahydrofurfurylamino)-6-methyl-7-anilinefluorane, 3-(N-ethyl-N-isobutylamino)-6-methyl-7-anilinefluorane, 3-(N-ethyl-N-ethoxypropylamino)-6-methyl-7-anilinefluorane, 3-cyclohexylamino-6-chlorofluorane, 2-(4-oxahexyl)-3-dimethylamino-6-methyl-7-anilinefluorane, 2-(4-oxahexyl)-3-diethylamino-6-methyl-7-anilinefluorane 2-(4-oxahexyl)-3-dipropylamino-6-methyl-7-aniline fluorane, 2-methyl-6-p-(p-dimethylaminophenyl)aminoaniline fluorane, 2-methoxy-6-p-(p-dimethylaminophenyl)aminoaniline fluorane, 2-chloro-3-methyl-6-p-(p-phenylaminophenyl)aminoaniline fluorane, 2-chloro-6-p-(p-dimethylaminophenyl)aminoaniline fluorane, 2-nitro-6-p-(p-diethylaminophenyl)aminoaniline fluorane, 2-amino-6-p-(p-diethylaminophenyl)aminoaniline fluorane, 2-diethylamino-6-p-(p-diethylaminophenyl)aminoaniline fluorane Ethylaminophenyl)aminoaniline fluorane, 2-phenyl-6-methyl-6-p-(p-phenylaminophenyl)aminoaniline fluorane, 2-benzyl-6-p-(p-phenylaminophenyl)aminoaniline fluorane, 2-hydroxy-6-p-(p-phenylaminophenyl)aminoaniline fluorane, 3-methyl-6-p-(p-dimethylaminophenyl)aminoaniline fluorane, 3-diethylamino-6-p-(p-diethylaminophenyl)aminoaniline fluorane, 3-diethylamino-6-p-(p-dibutylaminophenyl)aminoaniline fluorane, 2,4-dimethyl-6-[(4-dimethylamino)aniline]-fluorane.

[0093] <Fluorene-based leuco dyes>

[0094] 3,6,6'-Tris(dimethylamino)spiro[fluorene-9,3'-phthalide], 3,6,6'-Tris(diethylamino)spiro[fluorene-9,3'-phthalide].

[0095] <Divinyl leuco dyes>

[0096] 3,3-Bis-[2-(p-dimethylaminophenyl)-2-(p-methoxyphenyl)vinyl]-4,5,6,7-tetrabromophthalide, 3,3-Bis-[2-(p-dimethylaminophenyl)-2-(p-methoxyphenyl)vinyl]-4,5,6,7-tetrachlorophthalide, 3,3-Bis-[1,1-bis(4-pyrrolidinylphenyl)ethylene-2-yl]-4,5,6,7-tetrabromophthalide, 3,3-Bis-[1-(4-methoxyphenyl)-1-(4-pyrrolidinylphenyl)ethylene-2-yl]-4,5,6,7-tetrachlorophthalide.

[0097] <Other>

[0098] 3-(4-Diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindole-3-yl)-4-azaphthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-octyl-2-methylindole-3-yl)-4-azaphthalide, 3-(4-cyclohexylethylamino-2-methoxyphenyl)-3-(1-ethyl-2-methylindole-3-yl)-4-azaphthalide, 3,3-bis(1-ethyl-2-methylindole-3-yl)phthalide, 3,6-bis(diethylamino)fluorane-γ-(3'-nitro)anilinolactam, 3,6-bis(di-) Ethylamino)fluorane-γ-(4'-nitro)anilinolactam, 1,1-bis-[2',2',2",2"-tetra-(p-dimethylaminophenyl)-vinyl]-2,2-dionitrile ethane, 1,1-bis-[2',2',2",2"-tetra-(p-dimethylaminophenyl)-vinyl]-2-β-naphthoyl ethane, 1,1-bis-[2',2',2",2"-tetra-(p-dimethylaminophenyl)-vinyl]-2,2-diacetyl ethane, bis-[2,2,2',2'-tetra-(p-dimethylaminophenyl)-vinyl]-dimethylmalonate.

[0099] As the sensitizer used in this invention, existing known sensitizers can be used. Examples of such sensitizers include stearamide, palmitamide and other fatty acid amides, ethylene diamide, lignite wax, polyethylene wax, 1,2-bis-(3-methylphenoxy)ethane, p-benzylbiphenyl, β-benzyloxynaphthalene, 4-biphenyl-p-tolyl ether, m-terphenyl, 1,2-diphenoxyethane, dibenzyl oxalate, di(p-chlorobenzyl) oxalate, di(p-methylbenzyl) oxalate, dibenzyl terephthalate, and benzyl p-benzyloxybenzoate. Esters, phenyl-α-naphthyl carbonate, 1,4-diethoxynaphthalene, phenyl 1-hydroxy-2-naphthoic acid ester, o-xylene-bis(phenyl ether), 4-(m-methylphenoxymethyl)biphenyl, dibenzyl 4,4'-ethylenedioxy-bisbenzoate, dibenzoyloxymethane, 1,2-di(3-methylphenoxy)ethylene, bis[2-(4-methoxy-phenoxy)ethyl] ether, methyl p-nitrobenzene, phenyl p-toluenesulfonate, o-toluenesulfonamide, p-toluenesulfonamide, etc. These sensitizers can be used alone or in combination of two or more.

[0100] Examples of pigments used in this invention include kaolin, calcined kaolin, calcium carbonate, alumina, titanium dioxide, magnesium carbonate, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, and silicon dioxide. These pigments can also be used in combination depending on the required quality.

[0101] Examples of binders used in this invention include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, acetylated polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol, nitrile-modified polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol, silicone-modified polyvinyl alcohol, other modified polyvinyl alcohols, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, and cellulose derivatives such as ethyl cellulose and acetyl cellulose, casein, gum arabic, oxidized starch, etherified starch, dialdehyde starch, esterified starch, polyvinyl chloride, polyvinyl acetate, polyacrylamide, polyacrylate, polyvinyl butyral, polystyrene and its copolymers, polyamide resins, silicone resins, petroleum resins, terpene resins, ketone resins, coumarone resins, etc. These polymers can be used not only in solvents such as water, alcohols, ketones, esters, and hydrocarbons, but also in water or other media in an emulsified or dispersed paste-like state. Depending on the required quality, they can also be used in combination.

[0102] Examples of lubricants used in this invention include fatty acid metal salts such as zinc stearate and calcium stearate, waxes, and silicone resins.

[0103] In this invention, without impairing the desired effects on the aforementioned problems, as stabilizers to improve the oil resistance of the image section, 4,4'-butylidene (6-tert-butyl-3-methylphenol), 2,2'-di-tert-butyl-5,5'-dimethyl-4,4'-sulfonyldiphenol, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, etc., may be added. Furthermore, benzophenone-based and triazole-based ultraviolet absorbers, dispersants, defoamers, antioxidants, fluorescent dyes, etc., may be used.

[0104] The types and amounts of leuco dyes, developers, sensitizers, and other components used in the thermal recording layer of this invention can be determined according to the required performance and recording suitability, and are not particularly limited. Generally, relative to 1 part by weight of leuco dye, approximately 0.5 to 10 parts by weight of developer, 0.1 to 10 parts by weight of sensitizer, 0.5 to 20 parts by weight of pigment, 0.01 to 10 parts by weight of stabilizer, and 0.01 to 10 parts by weight of other components are used. A binder of approximately 5 to 25% by weight in the solid components of the thermal recording layer is appropriate.

[0105] In this invention, the leuco dye, color developer, and other materials added as needed are micronized to a particle size of less than several micrometers using a ball mill, atritor, sand grinder, or suitable emulsification device. A binder and various additives, depending on the purpose, are then added to prepare a coating liquid. Water or alcohol can be used as the solvent in this coating liquid, with a solid content of approximately 20-40% by weight.

[0106] In the thermal recording device of the present invention, an undercoating layer is provided between the support and the thermal recording layer.

[0107] The base coat mainly consists of binders and pigments.

[0108] As the adhesive used in the base layer, an adhesive that can be used in the aforementioned thermal recording layer can be appropriately used. One or more of these adhesives can be used.

[0109] The pigment used as a base coating contains hollow plastic particles. The hollow plastic particles used in this invention are tiny hollow particles that have a thermoplastic resin shell, contain air or other gases inside, and are in a foamed state. Examples of thermoplastic resins include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylate, polyacrylonitrile, polybutadiene, or copolymers thereof. Particularly preferred are styrene-based resins such as polystyrene, acrylic resins such as polyacrylate and polyacrylonitrile, copolymers thereof, or copolymer resins primarily composed of polyvinylidene chloride and polyacrylonitrile. Such organic hollow particles can be obtained as SX8782 manufactured by JSR Corporation, MH5055 and MH8108A manufactured by Zeon Corporation of Japan, ROPAQUE HP-91 manufactured by Rohm and Haas Japan, and microspheres manufactured by Matsumoto Oils & Fats Co., Ltd.

[0110] The volumetric hollowness of the plastic hollow particles used in this invention is preferably around 40% to 95%. A volumetric hollowness of 40% or more improves heat insulation and further enhances color rendering properties. Conversely, a volumetric hollowness of 95% or less improves the shell strength of the hollow particles, effectively maintaining the hollow state and easily obtaining a base coating with good surface strength. Here, the volumetric hollowness is calculated using (d³ / D³) × 100. In this formula, d represents the inner diameter of the organic hollow particle, and D represents the outer diameter of the organic hollow particle.

[0111] The base coating may contain pigments other than hollow plastic particles. For example, inorganic pigments such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, kaolin, calcined kaolin, clay, and talc, as well as organic pigments such as hollow plastic particles, can be used. One or more of these pigments can be used. As a pigment other than hollow plastic particles, calcined kaolin is preferred.

[0112] The pigment content in the base coat is typically 50–95% by weight, preferably 70–90% by weight, relative to the pigment (solid component) in the base coat. The content of hollow plastic particles in the base coat is 50% by weight or more, preferably 70–100% by weight, more preferably 80–100% by weight, relative to the pigment (solid component) in the base coat.

[0113] Depending on the requirements, various additives such as dispersants, plasticizers, pH adjusters, defoamers, water-retaining agents, preservatives, coloring dyes, and UV protectants can be appropriately added to the coating liquid of the primer layer.

[0114] The thermal recorder of the present invention may further have a protective layer on the thermal recording layer.

[0115] The protective layer mainly consists of binders and pigments, and crosslinking agents can be further added to it.

[0116] As the adhesive, an adhesive suitable for use in the aforementioned thermal recording layer can be appropriately used, preferably carboxyl-modified polyvinyl alcohol and non-core-shell acrylic resins with a glass transition temperature (Tg) higher than 50°C. One or more of these adhesives can be used.

[0117] Examples of crosslinking agents include epichlorohydrin resins such as polyamine epichlorohydrin resins and polyamide epichlorohydrin resins, polyamide urea resins, polyalkylene polyamine resins, polyalkylene polyamide resins, polyamine polyurea resins, modified polyamine resins, modified polyamide resins, polyalkylene polyamine urea-formaldehyde resins, or polyalkylene polyamine polyamide polyurea resins, glyoxal, hydroxymethyl melamine, melamine-formaldehyde resins, melamine urea resins, potassium persulfate, ammonium persulfate, sodium persulfate, ferric chloride, magnesium chloride, borax, boric acid, alum, and ammonium chloride. If the protective layer contains both an epichlorohydrin resin and a polyamine / polyamide resin as crosslinking agents, the water resistance becomes particularly good, and therefore it is preferred.

[0118] The amount of binder in the protective layer, or the total amount of binder and pigment, in terms of solid components, is typically 80.0 to 100.0% by weight, preferably 90.0 to 100.0% by weight, and the binder is preferably about 30.0 to 300.0% by weight relative to 100 parts by weight of pigment.

[0119] Depending on the requirements, various additives such as lubricants, stabilizers, ultraviolet absorbers, dispersants, defoamers, antioxidants, and fluorescent dyes that can be used in the above-mentioned thermal recording layers can be appropriately added to the coating liquid of the protective layer.

[0120] In this invention, there are no particular limitations on the means of coating the thermal recording layer and other coating layers besides the thermal recording layer, i.e., the protective layer, the primer layer, etc., and coating can be performed according to known and commonly used techniques. For example, an external coating machine or an internal coating machine equipped with various coating machines such as an air knife coating machine, a bar blade coating machine, a curved blade coating machine, an angled blade coating machine, a roller coating machine, and a curtain coating machine can be appropriately selected.

[0121] The coating weight of the thermal recording layer and other coating layers can be determined according to the required performance and recording adaptability, without particular limitations. The typical coating weight of the thermal recording layer, based on solid components, is 2–12 g / m². 2 The coating weight of the protective layer, based on the solid component, is preferably 0.5–5.0 g / m². 2 .

[0122] In addition, various well-known techniques in the field of thermal recording can be applied as needed after each layer is coated, such as smoothing treatments such as supercalendering.

[0123] Example

[0124] The present invention is illustrated below with examples, but is not intended to limit the present invention. It should be noted that, unless otherwise specified, in the various embodiments and comparative examples, "parts" means "parts by weight" and "%" means "% by weight".

[0125] To manufacture a thermal recorder, the dispersions and coatings can be prepared as follows.

[0126] [Preparation of each coating solution]

[0127] Stir and disperse the complex composed of the following formulations to prepare coating liquid 1-4 for the primer layer.

[0128] <Coating liquid for primer layer 1>

[0129] Fired kaolin (manufactured by BASF, trade name: ANSILEX 90) 40.0 parts

[0130] Hollow plastic particles (manufactured by Zeon Corporation, Japan; trade name: Nipol MH8108A; 50% hollow content; 27% solid content) 222.2 parts

[0131] Styrene / butadiene copolymer latex (manufactured by Zeon Corporation, Japan, trade name: ST5526, solid content 48%) 10.0 parts

[0132] <Coating liquid for primer layer 2>

[0133] 30.0 parts of calcined kaolin (ANSILEX 90)

[0134] Hollow plastic particles (Nipol MH8108A) 259.3 parts

[0135] Styrene / butadiene copolymer latex (ST5526) 10.0 parts

[0136] <Coating liquid for primer layer 3>

[0137] Fired kaolin (ANSILEX 90) 20.0 parts

[0138] 296.3 parts of hollow plastic particles (Nipol MH8108A)

[0139] Styrene / butadiene copolymer latex (ST5526) 10.0 parts

[0140] <Coating liquid for primer layer 4>

[0141] 10.0 parts of calcined kaolin (ANSILEX 90)

[0142] 333.3 parts of hollow plastic particles (Nipol MH8108A)

[0143] Styrene / butadiene copolymer latex (ST5526) 10.0 parts

[0144] <Coating liquid for primer layer 5>

[0145] Hollow plastic particles (Nipol MH8108A) 370.0 parts

[0146] Styrene / butadiene copolymer latex (ST5526) 10.0 parts

[0147] <Coating liquid for primer layer 6>

[0148] Fired kaolin (ANSILEX 90) 60.0 parts

[0149] 148.1 parts of hollow plastic particles (Nipol MH8108A)

[0150] Styrene / butadiene copolymer latex (ST5526) 10.0 parts

[0151] <Coating liquid for primer layer 7>

[0152] 50.0 parts of calcined kaolin (ANSILEX 90)

[0153] 185.1 parts of hollow plastic particles (Nipol MH8108A) Styrene / butadiene copolymer latex (ST5526) 10.0 parts

[0154] 50.0 parts water

[0155] <Coating liquid for primer layer 8>

[0156] 100.0 parts of calcined kaolin (ANSILEX 90) Styrene / butadiene copolymer latex (ST5526) 10.0 parts

[0157] 50.0 parts water

[0158] The color developer dispersion (Al~5 solution), leuco dye dispersion (B solution), and sensitizer dispersion (C solution) of the following formulations were each wet-milled using a sand mill until the average particle size was 0.5 μm.

[0159] Colorimetric reagent dispersion (A1 solution)

[0160] N,N'-bis-[3-(p-toluenesulfonyloxy)phenyl]urea (hereinafter referred to as "urea compound 1") 6.0 parts

[0161] Fully saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, trade name: PVA117, solid content 10%) 5.0 parts

[0162] 1.5 parts water

[0163] Colorimetric reagent dispersion (A2 solution)

[0164] The urea compound represented by the following chemical formula (Chemical Formula 9) (hereinafter referred to as "urea compound 2"), 6.0 parts.

[0165] [Chemical Formula 9]

[0166]

[0167] Fully saponified polyvinyl alcohol aqueous solution

[0168] (PVA117) 5.0 copies

[0169] 1.5 parts water

[0170] Colorimetric reagent dispersion (A3 solution)

[0171] N-[2-(3-phenylureo)phenyl]benzenesulfonamide (hereinafter referred to as "urea compound 3") 6.0 parts

[0172] 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0173] 1.5 parts water

[0174] Colorimetric reagent dispersion (A4 solution)

[0175] Urea carbamate compound represented by chemical formula (Chemical Formula 13) (manufactured by Fine Ace Co., Ltd., UU) 6.0 parts

[0176] [Chemical Formula 13]

[0177]

[0178] 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0179] 1.5 parts water

[0180] Colorimetric reagent dispersion (A5 solution)

[0181] 4-Hydroxy-4'-isopropoxydiphenyl sulfone (manufactured by Mitsubishi Chemical Corporation, trade name: NYDS) 6.0 parts

[0182] 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0183] 1.5 parts water

[0184] Leuco dye dispersion (solution B)

[0185] 3-Dibutylamino-6-methyl-7-aniline fluorane (manufactured by Yamamoto Chemical Co., Ltd., trade name: ODB-2) 6.0 parts

[0186] 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0187] 1.5 parts water

[0188] Sensitizer dispersion (C solution)

[0189] 1,2-Bis-(3-methylphenoxy)ethane (manufactured by Samkwang Corporation, trade name: KS232) 6.0 parts

[0190] 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0191] 1.5 parts water

[0192] Next, the dispersions are mixed in the following proportions to prepare a coating solution for the thermal recording layer.

[0193] Coating solution for thermal recording layers

[0194] Colorimetric reagent dispersion (A1 solution) 36.0 parts

[0195] Leuco dye dispersion (solution B) 18.0 parts

[0196] Sensitizer dispersion (C solution) 5.0 parts

[0197] 25.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0198] Next, the complexes in the following proportions will be mixed to prepare a coating liquid for the protective layer.

[0199] <Protective Coating Liquid>

[0200] Aluminum hydroxide dispersion (manufactured by Martinswerk, trade name: Martifin OL, 50% solid content) 9.0 parts

[0201] Carboxyl-modified polyvinyl alcohol aqueous solution (manufactured by Kuraray, trade name: KL318, degree of polymerization: approx. 1800, degree of saponification: 85-90 mol%, solid content 10%) 30.0 parts

[0202] Polyamide epichlorohydrin resin (manufactured by Starlight PMC Co., trade name: WS4030, solid content 25%) 4.0 parts

[0203] Modified polyamine resin (manufactured by Taoka Chemical Co., trade name: Sumirez Resin SPI-102A, solid content 45%) 2.2 parts

[0204] Zinc stearate (manufactured by Chukyo Yushi Co., trade name: HYDRIN Z-7-30, solid content 30%) 2.0 parts

[0205] [Example 1]

[0206] Using the bending blade coating method, a coating liquid 1 for the base coat was coated on one side of a support (high-grade paper with a basis weight of 47 g / m 2 (Japanese: jisshitsu-shi)) so that the coating amount in terms of solid content became 10.0 g / m 2 , and then dried to obtain a base coat-coated paper.

[0207] Using the bar blade coating method, a coating liquid for the thermal recording layer was coated on the base coat of the base coat-coated paper so that the coating amount in terms of solid content became 6.0 g / m 2 , and then dried and treated with a super calender to make the smoothness 100 - 500 seconds to produce a thermal recording medium.

[0208] [Example 2]

[0209] Instead of coating liquid 1 for the base coat, coating liquid 3 for the base coat was used. The compounding amount of liquid A1 in the coating liquid for the thermal recording layer was changed to 18 parts. Further, 18 parts of liquid A4 was added to the coating liquid for the thermal recording layer. Otherwise, the operation was the same as in Example 1 to produce a thermal recording medium.

[0210] [Example 3]

[0211] Instead of coating liquid 1 for the base coat, coating liquid 3 for the base coat was used. Instead of liquid A1 in the coating liquid for the thermal recording layer, liquid A2 was used. Otherwise, the operation was the same as in Example 1 to produce a thermal recording medium.

[0212] [Example 4]

[0213] Instead of coating liquid 1 for the base coat, coating liquid 3 for the base coat was used. Instead of liquid A1 in the coating liquid for the thermal recording layer, liquid A3 was used. Otherwise, the operation was the same as in Example 1 to produce a thermal recording medium.

[0214] [Example 5]

[0215] Instead of the primer coating liquid 1, the primer coating liquid 4 is used. The amount of liquid A1 in the thermal recording layer coating liquid is changed to 18 parts. Then, 18 parts of liquid A2 are added to the thermal recording layer coating liquid. Otherwise, the thermal recording body is produced in the same manner as in Example 1.

[0216] [Example 6]

[0217] Instead of the base coat coating liquid 1, the base coat coating liquid 2 is used. The amount of liquid A1 in the thermal recording layer coating liquid is changed to 18 parts. Then, 18 parts of liquid A3 are added to the thermal recording layer coating liquid. Otherwise, the thermal recording body is produced in the same manner as in Example 1.

[0218] [Example 7]

[0219] Instead of the primer coating liquid 1, the primer coating liquid 3 is used. The amount of liquid A1 in the thermal recording layer coating liquid is changed to 18 parts. Then, 18 parts of liquid A3 are added to the thermal recording layer coating liquid. Otherwise, the thermal recording body is produced in the same manner as in Example 1.

[0220] [Example 8]

[0221] Instead of the primer coating liquid 1, the primer coating liquid 5 is used. The amount of liquid A1 in the thermal recording layer coating liquid is changed to 18 parts. Then, 18 parts of liquid A3 are added to the thermal recording layer coating liquid. Otherwise, the thermal recording body is manufactured in the same manner as in Example 1.

[0222] [Example 9]

[0223] Using a rod-blade method, a protective coating liquid is applied to the thermal recording layer of the thermal recording layer coated paper, resulting in a coating weight of 2.0 g / m² based on solid components. 2 Then, it is dried and processed with a supercalender to achieve a smoothness of 100-500 seconds. Otherwise, it is operated in the same manner as in Example 8 to produce a thermal recorder.

[0224] [Example 10]

[0225] Instead of the primer coating liquid 1, the primer coating liquid 3 is used. The amount of liquid A1 in the thermal recording layer coating liquid is changed to 18 parts. Then, 9 parts of liquid A3 and 9 parts of liquid A4 are added to the thermal recording layer coating liquid. Otherwise, the thermal recording body is produced in the same manner as in Example 1.

[0226] [Example 11]

[0227] Instead of the base coat coating liquid 1, use the base coat coating liquid 3, without using liquid A1 in the thermal recording layer coating liquid, add 18 parts of liquid A2 and 18 parts of liquid A3, and otherwise operate in the same manner as in Example 1 to produce a thermal recorder.

[0228] [Comparative Example 1]

[0229] The thermal recorder was fabricated by changing the base coat coating liquid 1 to the base coat coating liquid 6, but otherwise operating in the same manner as in Example 1.

[0230] [Comparative Example 2]

[0231] The thermal recorder was fabricated in the same manner as in Example 3, without the application of a base coating.

[0232] [Comparative Example 3]

[0233] The thermal recorder was fabricated by changing the base coat coating liquid 3 to the base coat coating liquid 8, and otherwise operating in the same manner as in Example 3.

[0234] [Comparative Example 4]

[0235] The thermal recorder was fabricated by changing the base coat coating liquid 3 to the base coat coating liquid 6, and otherwise operating in the same manner as in Example 4.

[0236] [Comparative Example 5]

[0237] The thermal recorder was fabricated by changing the base coat coating liquid 4 to the base coat coating liquid 6, and otherwise operated in the same manner as in Example 5.

[0238] [Comparative Example 6]

[0239] The thermal recorder is fabricated in the same manner as in Example 5, without the application of a base coating.

[0240] [Comparative Example 7]

[0241] The thermal recorder was fabricated by changing the base coat coating liquid 4 to the base coat coating liquid 8, and otherwise operated in the same manner as in Example 5.

[0242] [Comparative Example 8]

[0243] The thermal recorder is fabricated in the same manner as in Example 6, without the application of a base coating.

[0244] [Comparative Example 9]

[0245] The thermal recorder was fabricated by changing the base coat coating liquid 2 to the base coat coating liquid 8, and otherwise operated in the same manner as in Example 6.

[0246] [Comparative Example 10]

[0247] The thermal recorder is fabricated in the same manner as in Example 11, without the application of a base coating.

[0248] [Comparative Example 11]

[0249] The thermal recorder was fabricated by changing the base coat coating liquid 3 to the base coat coating liquid 8, otherwise operating in the same manner as in Example 11.

[0250] [Comparative Example 12]

[0251] The base coat coating liquid 1 was changed to base coat coating liquid 7. In the coating liquid for the thermal recording layer, liquid A1 was not added, but 36.0 parts of liquid A5 were added. Otherwise, the thermal recording body was prepared in the same manner as in Example 1.

[0252] [Comparative Example 13]

[0253] The base coat coating liquid 1 was changed to base coat coating liquid 3. In the coating liquid for the thermal recording layer, liquid A1 was not added, but 36.0 parts of liquid A5 were added. Otherwise, the thermal recording body was prepared in the same manner as in Example 1.

[0254] The following evaluation is performed on the thermal recording device produced.

[0255] <Color rendering properties (printing density)>

[0256] For the thermal recording media, a grid pattern was printed using an TH-PMD (thermal recording paper printing test machine, equipped with a Kyocera thermal head) manufactured by Okura Electric Co., Ltd., at a printing speed of 50 mm / sec and an applied energy of 0.41 mJ / dot. The printing density of the printing section was measured using a Macbeth density meter (RD-914, using an amber filter) to evaluate the color rendering performance (printing density).

[0257] <Adaptability to high-speed printing>

[0258] For the thermal recorder, a Zebra 140XiIII label printer was used to print the barcode (CODE39) in both the longitudinal (barcode orthogonal to the print head movement direction) and transverse (barcode parallel to the print head movement direction) conditions at a print level of +10 and a print speed of 30.4 cm / s (12 inches / s).

[0259] Next, for the printed barcodes, a barcode verification machine (Honeywell QCPC600, 640nm light source) was used to conduct reading tests to evaluate the barcode reading adaptability. The evaluation results were recorded using the ANSI standard symbol grade.

[0260] Symbol rating: Divide the barcode into 10 parts along the direction perpendicular to the bar, perform a reading test at each position, and use a 5-level rating of (excellent) A, B, C, D, and F (poor) to represent the average value.

[0261] <Heat resistance of the white paper section>

[0262] For the thermal recorder, after being treated at 80°C for 24 hours, it was left to stand at 23°C for 50% RH for 3 hours.

[0263] The concentration of the non-printing section (white paper section) was measured using a Macbeth concentration meter (RD-914, using an amber filter). The base color value was calculated from the difference between the values ​​before and after treatment. The heat resistance of the non-printing section (white paper section) was evaluated according to the following criteria.

[0264] Background color value = (Concentration of non-printing areas after processing) - (Concentration of non-printing areas before processing)

[0265] Advantages: The background color chromaticity value is less than 0.3;

[0266] Allowed: The background color value is 0.3 or higher and less than 0.5;

[0267] Not allowed: The background color value is 0.5 or higher.

[0268] <Plasticizer Resistance>

[0269] For the thermal recorder, a grid pattern was printed using the TH-PMD (thermal recording paper printing test machine, equipped with a Kyocera thermal head) manufactured by Okura Electric Co., Ltd., under the conditions of applying energy of 0.41mJ / dot and printing speed of 50mm / sec.

[0270] After wrapping a layer of polyvinyl chloride (PVC) cling film (Mitsui Chemicals Hi-LapKMA) around a paper tube, a printed thermal recorder is attached, and then three layers of PVC cling film are wrapped around it. The tube is then left to stand for 24 hours at 40°C.

[0271] The printing density of the printing section was measured using a Macbeth density meter (RD-914, with an amber filter), and the residual rate was calculated from the values ​​before and after treatment to evaluate the plasticizer resistance.

[0272] Residual rate (%) = (Print density of the printed section after treatment / Print density of the printed section before treatment) × 100

[0273] Advantages: Survival rate is over 90%;

[0274] Acceptable: The survival rate is above 70% and less than 90%;

[0275] Not allowed: Survival rate less than 70%.

[0276] <Printing performance (heat-sensitive tip chip resistance)>

[0277] For the thermal recorder, a 10cm grid was printed using a SATO label printer (L'espritR-8). The debris (thermal head debris) that adhered to the thermal head after printing was evaluated visually according to the following criteria.

[0278] Advantage: Almost no thermal head debris was observed adhering to the surface.

[0279] A small amount of thermal head debris was observed adhering to the image, but no defects or scratches were observed in the resulting image, indicating that it is practically problem-free.

[0280] Unacceptable: A large amount of thermal head debris was observed adhering to the image, resulting in missing parts and scratches.

[0281] The results are shown in the table below.

[0282] [Table 1]

[0283]

[0284] [Table 2]

[0285]

Claims

1. A heat-sensitive recording body, which is provided with a primer layer on a support, and a heat-sensitive recording layer containing a non-colored or light-colored electron-donating leuco dye and an electron-accepting color developer on the primer layer, In the heat-sensitive recording layer, as an electron-accepting color developer, at least two kinds of urea compounds selected from the following (1) to (3) are contained, wherein, not more than two are selected from (1), (2), or (3) each, in the primer layer, a pigment is contained at 50% by weight or more to 95% by weight or less in terms of solid content, and a plastic hollow particle is contained at 50% by weight or more in terms of solid content relative to the pigment, (1) a first urea compound represented by the following general formula 6, Formula 6 In Chemical Formula 6, R 9 optionally the same or different, represent an alkyl group having 1 to 4 carbons, o represents an integer of 0 to 1, and the position of R 9 in the benzene ring is the 4-position, (2) a second urea compound represented by the following general formula 8, Formula 8, (3) a third urea compound represented by N-[2-(3-phenylureido)phenyl]benzenesulfonamide, in the heat-sensitive recording body, a content of the urea compound in the heat-sensitive recording layer is 1.0% by weight or more to 70.0% by weight or less in terms of solid content, a content of the first urea compound in the heat-sensitive recording layer is 1.0% by weight or more to 50.0% by weight or less in terms of solid content, or a content of the second urea compound in the heat-sensitive recording layer is 5.0% by weight or more to 50.0% by weight or less in terms of solid content, or a content of the third urea compound in the heat-sensitive recording layer is 5.0% by weight or more to 50.0% by weight or less in terms of solid content, but the total content of the first to third urea compounds used is within the above range.

2. The heat-sensitive recording body according to claim 1, wherein the heat-sensitive recording layer contains a color developer other than the first, second, and third urea compounds, a total content of the first, second, and third urea compounds in terms of solid content is 90% by weight or more relative to the total color developer contained in the heat-sensitive recording layer.

3. The heat-sensitive recording body according to claim 1 or 2, wherein a volume void ratio of the plastic hollow particle is 40% or more to 95% or less.

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