# US 9,434,199 B2 · Thermal recording material

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- Number: US 9,434,199 B2
- Document ID: US9434199B2
- Status: Granted
- Kind: B2
- Application number: 14/386,657
- Filed: 2013-03-19
- Published: 2015-02-19
- Granted: 2016-09-06
- Earliest claimed: 2012-03-21
- Assignees: Fine Ace Corporation
- Applicants: Fine Ace Corporation
- Inventors: Kazuo Kabashima
- Web page: https://patentgrep.com/patent/US9434199B2

## CPC

- B41M 5/3336: {Sulfur compounds, e.g. sulfones, sulfides, sulfonamides}
- B41M 5/3375: {Non-macromolecular compounds}
- C07C 315/04: by reactions not involving the formation of sulfone or sulfoxide groups
- C07C 317/22: with sulfone or sulfoxide groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- B41M 2205/04: Direct thermal recording [DTR]
- B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A thermal recording material having both of excellent coloring property and storage stability with a low cost is provided. The thermal recording material contains a leuco dye and a developer in a coloring layer, and the developer contains 2,4′-dihydroxydiphenylsulfone and 4,4′-dihydroxydiphenylsulfone with a specific ratio, and the above-mentioned two kinds of the dihydroxydiphenylsulfones are made a material obtained by sequentially undergoing a separating step for heightening the weight ratio of a 2,4′ material from a dichlorodiphenylsulfone mixture containing the 2,4′ material and a 4,4′ material, a reaction step of hydrolyzing the mixture to obtain a dihydroxydiphenylsulfone mixture, and a post-treatment step of subjecting to decolorization and purification.

## Claims

### Claim 1

A thermal recording material comprising:
a support and a coloring layer containing a colorless or pale colored dye precursor and a developer provided thereon, wherein the developer contains 2,4′-dihydroxydiphenylsulfone and 4,4′-dihydroxydiphenylsulfone, and
a weight ratio of the 2,4′-dihydroxydiphenylsulfone and the 4,4′-dihydroxydiphenylsulfone is within a range of exceeding 50/50 and 95/5 or less,
wherein the 2,4′-dihydroxydiphenylsulfone and the 4,4′-dihydroxydiphenylsulfone comprises 2,4′-dihydroxydiphenylsulfone and 4,4′-dihydroxydiphenylsulfone obtained by sequentially undergoing:
a separating step of obtaining a second mixture where a weight ratio of 2,4′-dichlorodiphenylsulfone is heightened from a first mixture containing the 2,4′-dichlorodiphenylsulfone and 4,4′-dichlorodiphenylsulfone,
a reaction step of reacting the second mixture to obtain a third mixture containing the 2,4′-dihydroxydiphenylsulfone and the 4,4′-dihydroxydiphenylsulfone, and
a post-treatment step of decolorizing and purifying the third mixture.

### Claim 2 (depends on 1)

The thermal recording material according to claim 1, wherein the weight ratio is substantially determined by undergoing a series of the steps.

### Claim 3 (depends on 1)

The thermal recording material according to claim 1, wherein the separating step contains a crystal precipitating step.

### Claim 4 (depends on 1)

The thermal recording material according to claim 1, wherein the separating step gives a material in which a weight ratio of the 2,4′-dichlorodiphenylsulfone and the 4,4% dichlorodiphenylsulfone is within a range of exceeding 50/50 and 95/5 or less by one separation.

### Claim 5 (depends on 1)

The thermal recording material according to claim 1, wherein the reaction of obtaining the third mixture is a hydrolysis reaction.

### Claim 6 (depends on 1)

The thermal recording material according to claim 1, wherein the reaction of obtaining the third mixture is a hydrolysis reaction carried out by adding an alkali.

### Claim 7 (depends on 1)

The thermal recording material according to claim 1, wherein the reaction step is to obtain a third mixture by adjusting a pH after the hydrolysis reaction.

### Claim 8 (depends on 1)

The thermal recording material according to claim 1, wherein the post-treatment step is a step wherein discoloration and purification are carried out by recrystallization using a solvent.

### Claim 9 (depends on 1)

The thermal recording material according to claim 1, wherein the coloring layer further contains at least one compound, as an auxiliary agent, selected from the following (A), (B) and (C):
(A) a trisphenol type compound represented by the following formula (I):
wherein R1 represents an alkyl group having 4 or less carbon atoms or a cyclohexyl group, and R2 represents an alkyl group having 4 or less carbon atoms,
(B) a diphenylsulfone crosslinking type compound represented by the following formula (II):
wherein n represents a numeral of 1 to 7,
(C) a urea urethane compound having a molecular weight of 2,000 or less, having both of a urea group(s) and a urethane group(s) in a molecular structure, and aromatic compound residues are directly bonded to both ends of the respective urea group(s) and urethane group(s).

### Claim 10 (depends on 9)

The thermal recording material according to claim 9, wherein the (C) is a urea urethane compound represented by the following formula (III) or (IV):
wherein X and Y each represent an aromatic compound residue, α represents an aromatic compound residue having a valence number of divalent or more, n represents an integer of 2 or more, and each residue may optionally have a substituent(s)
wherein Z and Y each represent an aromatic compound residue, β represents an aromatic compound residue having a valence number of divalent or more, n represents an integer of 2 or more, and each residue may optionally have a substituent(s).

### Claim 11 (depends on 9)

The thermal recording material according to claim 9, wherein the (C) is a urea urethane compound represented by the following formula (V):

### Claim 12 (depends on 9)

The thermal recording material according to claim 9, wherein the coloring layer contains at least one compound selected from diphenylsulfone, m-terphenyl, 4-benzylbiphenyl, 1,2-bis(3,4-dimethylphenyl)ethane, 2-benzyloxynaphthalene, 1,2-diphenoxymethylbenzene, 1,2-diphenoxyethane, 1,2-bis(3-methylphenoxy)ethane, dibenzyl oxalate, di(4-chlorobenzyl) oxalate, di(4-methylbenzyl) oxalate, dibenzyl terephthalate, stearic acid amide and 4-acetylbiphenyl as a sensitizer.

### Claim 13 (depends on 9)

The thermal recording material according to claim 9, wherein the coloring layer further contains at least one compound selected from 2,2-bis(4-hydroxyphenyl)propane, benzyl 4-hydroxybenzoate, an oligomer of hydroxybenzoate, 4-n-octyloxycarbonylaminosalicylic acid or a metal salt thereof, butyl bis(4-hydroxyphenyl)acetate, bis(3-allyl-4-hydroxyphenyl)sulfone,4-hydroxy-4′-isopropoxydiphenylsulfone,4-hydroxy-4′-n-propoxydiphenylsulfone,4,4′-bis(p-toluenesulfonylaminocarbonylamino)diphenylmethane, 4-hydroxy-4′-allyloxydiphenylsulfone,N-p-toluenesuifonyl-N′-3-(p-toluenesulfonyloxy)phenylurea, 4,4′-butylidenebis(6-t-butyl-3-methylphenol) and sulfonylurea derivative, as a developer.

### Claim 14 (depends on 9)

The thermal recording material according to claim 9, wherein the coloring layer further contains at least one compound selected from 4,4′-thiobis(2-methyl-6-t-butylphenol), 4,4′-thiobis(3-methyl-6-t-butylphenol), 2,2′-thiobis(6-t-butyl-4-methylphenol), 2,2′-methylenebis(4-methyl-6-t-butylphenol), tris(2,6-dimethyl-4-t-butyl-3-hydroxybenzyl)isocyanurate, 4-benzyloxy-4′-(2-methylglycidyloxy)diphenylsulfone,4,4′-diglycidyloxydiphenylsulfone, sodium-2,2′-methylenebis(4,6-di-t-butylphenyl)phosphate and N,N′-di-2-naphthyl-p-phenylenediamine as a preservation stabilizer.

### Claim 15 (depends on 1)

The thermal recording material according to claim 1, wherein the coloring layer contains at least one compound selected from diphenylsulfone, m-terphenyl, 4-benzylbiphenyl, 1,2-bis(3,4-dimethylphenyl)ethane, 2-benzyloxynaphthalene, 1,2-diphenoxymethylbenzene, 1,2-diphenoxyethane, 1,2-bis(3-methylphenoxy)ethane, dibenzyl oxalate, di(4-chlorobenzyl) oxalate, di(4-methylbenzyl) oxalate, dibenzyl terephthalate, stearic acid amide and 4-acetylbiphenyl as a sensitizer.

### Claim 16 (depends on 1)

The thermal recording material according to claim 1, wherein the coloring layer further contains at least one compound selected from 2,2-bis(4-hydroxyphenyl)propane, benzyl 4-hydroxybenzoate, an oligomer of hydroxybenzoate, 4-n-octyloxycarbonylaminosalicylic acid or a metal salt thereof, butyl bis(4-hydroxyphenyl)acetate, bis(3-allyl-4-hydroxyphenyl)sulfone,4-hydroxy-4′-isopropoxydiphenylsulfone,4-hydroxy-4′-n-propoxydiphenylsulfone,4,4′-bis(p-toluenesulfonylaminocarbonylamino)diphenylmethane, 4-hydroxy-4′-allyloxydiphenylsulfone,N-p-toluenesulfonyl-N′-3-(p-toluenesulfonyloxy)phenylurea, 4,4′-butylidenebis(6-t-butyl-3-methylphenol) and sulfonylurea derivative, as a developer.

### Claim 17 (depends on 1)

The thermal recording material according to claim 1, wherein the coloring layer further contains at least one compound selected from 4,4′-thiobis(2-methyl-6-t-butylphenol), 4,4′-thiobis(3-methyl-6-t-butylphenol), 2,2′-thiobis(6-t-butyl-4-methylphenol), 2,2′-methylenebis(4-methyl-6-t-butylphenol), tris(2,6-dimethyl-4-t-butyl-3-hydroxybenzyl)isocyanurate, 4-benzyloxy-4′-(2-methylglycidyloxy)diphenylsulfone,4,4′-diglycidyloxydiphenylsulfone,sodium-2,2′-methylenebis(4,6-di-t-butylphenyl)phosphate and N,N′-di-2-naphthyl-p-phenylenediamine as a preservation stabilizer.