JP2003160555A - NEW p-HYDROXYBENZOIC ACID ESTER DERIVATIVE AND HEAT- SENSITIVE RECORDING MATERIAL USING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a new color developer which reduces the occurrence of fogging and has good sensitivity and concentration of developing, and has the excellent storage stability of a developing image. <P>SOLUTION: When a new p-hydroxybenzoic acid ester derivative in which a p-hydroxybenzoyloxy group and a sulfonylamino group are adjacently positioned to each other through an alkylene group, concretely, 2-(toluene-4- sulfonylamino)ethyl p-hydroxybenzoate, 2-(benzenesulfonylamino)ethyl p- hydroxybenzoate 2-(4-chlorobenzene sulfonylamino)ethyl p-hydroxybenzoate or the like are used as a color developer for a heat-sensitive recording material, the developing sensitivity of the new p-hydroxy benzoic acid ester or the developing concentration thereof is the same as those of known conventional color developers such as benzyl p-hydroxybenzoate and bisphenol A, and the occurrence of fogging is reduced, and further the storage stability of the developing image is remarkably improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel p-hydroxybenzoic acid ester derivative having a sulfonylamino group in the molecule, and a heat-sensitive recording material using the derivative, which retains good color development sensitivity and color density. On the other hand, there is little background stain and the storage stability of a color image is excellent.

[0002]

BACKGROUND OF THE INVENTION Thermal recording paper, carbonless paper, and the like are well known as recording materials that utilize the color-forming reaction between a color-forming agent that is an electron-donating colorless dye and an electron-accepting developer. Among them, thermosensitive recording materials have the advantage that clear recording can be obtained with a relatively simple device, so that facsimiles, recorders for measurement, computer-terminals, label printers, ticket issuing machines such as ticket, printers, etc. Widely used in various fields. These heat-sensitive recording materials are basically finely pulverized water in which constituent components such as a color former, a color developer, a sensitizer for improving color development sensitivity, and a pigment are separately controlled in particle size by an adhesive-added system. After being prepared as a dispersion liquid, it is mixed, coated on a support such as plastic, paper, and synthetic paper, dried, and finished as a thermosensitive coloring layer.

The heat-sensitive recording material is required to have a white background, high color-developing sensitivity and high density at low energy, and excellent storage stability of images under various environments.
The color developing agent for heat-sensitive recording is mainly 2,2-bis (4
-Hydroxyphenyl) propane (common name: bisphenol A) is widely used. Sufficient color development sensitivity is imparted to this compound by selecting a sensitizer, but on the other hand, stability of a color image is likely to be impaired by aging, heat, plasticizer in plastic, oil, sunlight, etc. Therefore, it is actually used in the field where preservation is not required so much. In addition, the above bisphenol A
It is used in large quantities as an industrial raw material for plastics because of its low manufacturing cost, but in recent years, there is concern about environmental hormones, and a new color developer for heat-sensitive recording that replaces this is also desired from this viewpoint. There is.

[0004]

2. Description of the Related Art As a developer for heat-sensitive recording which replaces the above bisphenol A, for example, JP-A-54-74762 (Prior Art 1) discloses ethyl p-oxybenzoate, p-oxybenzoate.
Disclosed are p-hydroxybenzoic acid ester compounds such as -butyl oxybenzoate, heptyl p-oxybenzoate, and benzyl p-oxybenzoate. Above all,
Benzyl p-hydroxybenzoate has the advantages of low color energy, high color development sensitivity, high color density, and low background fog, but like bisphenol A, the storage stability of the color image is insufficient and it fades over time. However, it cannot be used as it is because of the phenomenon of white clearing.

Then, there is the following conventional technique for improving the storability of a color image by changing a part of the structure of the p-hydroxybenzoic acid ester compound. (1) JP-A-59-199286 (Prior Art 2) HO-ph-CO-OR-O-CO-ph-OH (R
Is a C ₂ -C ₁₂ alkylene group; ph is a phenylene group), glycol-bis-p-
A heat-sensitive recording paper using a hydroxybenzoic acid ester as a color developer is disclosed, and it is described that it has suitability for high-speed recording and that fading and white spots of recorded images are improved.

(2) JP-A-7-173108 (Prior Art 3) A 3,4-dihydroxybenzoic acid ester derivative is disclosed as a color developer for heat-sensitive recording, and the storage stability of an image, particularly heat resistance, is disclosed. It is described as being excellent.

(3) Japanese Patent Application Laid-Open No. 11-322727 (Prior Art 4) As a developer for heat-sensitive recording, a hydroxybenzoic acid ester compound represented by the general formula (B) is disclosed, which is disclosed under severe conditions. It is described that the color development part after storage and the discoloration of the background part are little and excellent in various storage stability.

[Chemical 2]

[0008] Further, by using the above-mentioned benzyl p-hydroxybenzoate which is excellent in color developing sensitivity in combination with other components, it is possible to improve the image storability.
It is as follows. (4) JP-A-59-209192 (Prior Art 5) An undercoat layer containing a compound represented by the general formula (C) was formed on the lower surface of a color forming layer using benzyl p-hydroxybenzoate. A heat-sensitive recording material is disclosed, and it is described that the heat-resistant decoloring property and bleeding property of the image area can be improved.

[Chemical 3] (In the formula (C), R is a C ₂ -C ₅ alkylene group.)

(5) Japanese Patent Application Laid-Open No. 59-218891 (Prior Art 6) Benzyl p-hydroxybenzoate is used as a color developer, and dibenzyl terephthalate is used as a sensitizer, a coloring aid and a storage stabilization aid. A heat-sensitive recording material containing three functional agents is disclosed, and it is described that storage stability is improved such as prevention of discoloration after recording and discoloration due to fingerprint adhesion.

(6) Japanese Patent Application Laid-Open No. 58-211493 (Prior Art 7) A heat-sensitive recording material in which a sulfamide compound represented by the general formula (D) is used in combination with a developer such as p-hydroxybenzoic acid ester. It is disclosed that the image storability is improved.

[Chemical 4] (In the formula (D), R ₃ and R ₄ are each hydrogen, halogen, an aryl group, a trihalogenomethyl group, or a C _{1 to} C ₃₀ alkyl group.)

(7) JP-A-58-87089 (Prior Art 8) A heat-sensitive recording paper is disclosed in which a developer such as p-hydroxybenzoic acid ester is used in combination with a hindered phenol compound. It is described that the decoloring property due to heat and humidity can be suppressed.

(8) JP-A-59-41296 (Prior Art 9) A heat-sensitive recording sheet using p-hydroxybenzoic acid benzyl ester as a developer and zinc N-ethyl-N-phenyldithiocarbamate. Is disclosed, heat resistance,
It is described that storage stability such as moisture resistance and grease resistance can be achieved.

(9) Japanese Patent Publication No. 26874/1990 (Prior Art 10) A developer such as p-hydroxybenzoic acid ester is added to a metal salt of p-alkylbenzoic acid represented by the general formula (E), or O.
-A heat-sensitive recording material in which a metal salt of benzoylbenzoic acid is used in combination is disclosed, and it is described that the color image is stable and the ground color is stable even under high humidity conditions.

[Chemical 5] (In the formula (E), R ₅ is hydrogen or a C ₁ -C ₃ alkyl group;
R ₆ when R ₅ is hydrogen, CO-C ₆ H _5, shows a hydrogen otherwise; M represents a polyvalent metal. )

[0014]

In the above prior art, p
-Hydroxybenzoic acid ester retains the features of high sensitivity, high color density, and low background stain, but on the other hand, it is not at a sufficiently satisfactory level in terms of improving storage stability of color images and preventing whitening. , Further improvement is required. The present invention is a novel developer which can substitute for the above-mentioned bisphenol A or a known p-hydroxybenzoic acid ester compound, has less background fog, good color development sensitivity and color density, and is further excellent in storage stability of a color image. The development of colorants is a technical issue.

[0015]

Means for Solving the Problems The inventors of the present invention have intensively studied to solve the above-mentioned problems mainly on p-hydroxybenzoic acid ester, and as a result, a novel p-hydroxybenzoic acid having a sulfonylamino group in the molecule. Ester compounds,
More specifically, when a p-hydroxybenzoic acid ester derivative in which a p-hydroxybenzoyloxy group and a sulfonylamino group are positioned adjacent to each other via an alkylene group is used as a developer for heat-sensitive recording, a sulfonylamino group is obtained. It has been found that the presence of the compound can improve the storage stability of the image to a satisfactory level while maintaining the color development sensitivity and color density.
The present invention has been completed.

That is, the present invention 1 is represented by the following general formula (A).

[Chemical 6] (In the formula (A), R ₁ is a C ₂ -C ₄ alkylene group; R ₂ is an unsubstituted benzene ring, or one of an alkyl group, a phenyl group, a cycloalkyl group, an alkoxyl group, a halogen atom, or Two or more are benzene rings substituted with 1 to 4. However, when R ₂ is the substituted benzene ring, adjacent substituents may be bonded to each other to further form a benzene ring or an alicyclic ring. ) A novel p-hydroxybenzoic acid ester derivative having a sulfonylamino group in the molecule.

The second aspect of the present invention is p-hydroxybenzoic acid 2-
(Toluene-4-sulfonylamino) ethyl, 2- (benzenesulfonylamino) ethyl p-hydroxybenzoate,
Novel p selected from the group consisting of 2- (4-chlorobenzenesulfonylamino) ethyl p-hydroxybenzoate
-A hydroxybenzoic acid ester derivative.

The present invention 3 is a heat-sensitive recording material containing a color-developing agent and a color-developing agent, wherein the color-developing agent is the p-hydroxybenzoate derivative of the present invention 1 or 2. is there.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is firstly a novel p-hydroxybenzoic acid ester derivative having a sulfonylamino group in the molecule, and secondly, a structural formula belongs to the first novel derivative. Specific compounds such as 2- (toluene-4-sulfonylamino) ethyl p-hydroxybenzoate and 2- (benzenesulfonylamino) ethyl p-hydroxybenzoate. Thirdly, these compounds are used as a developer. It is a heat-sensitive recording material used for.

The novel p-hydroxybenzoic acid ester derivative having a sulfonylamino group in the molecule of the present invention 1 is represented by the above general formula (A), and basically comprises a p-hydroxybenzoyloxy group and a sulfonylamino group. The groups have a structure in which they are adjacent to each other via an alkylene group. R ₁ of the formula (A) is C ₂ ~
It is a C ₄ alkylene group, and ethylene group and propylene group are preferable. This propylene group is a concept including both an n-propylene group and an isopropylene group. R _{2 of} formula (A)
Is an unsubstituted benzene ring or a substituted benzene ring. In the case of this substituted benzene ring, the substituent bonded to the benzene ring is an alkyl group, a phenyl group, a cycloalkyl group, an alkoxyl group, or a halogen atom. C as an alkyl group
₁ -C ₄ alkyl, C ₅ -C ₆ is a cycloalkyl group
Cycloalkyl is preferably C ₁ -C ₄ alkoxyl as the alkoxyl group. As halogen, chlorine,
Bromine and iodine are preferred. The number of bonded substituents is 1 to
When the number of the substituents is 4, the number of the substituents is plural, and only one kind may be bonded to the benzene ring, or two or more kinds may be bonded. In the case of a substituted benzene ring, adjacent substituents may be bonded to each other to further form a benzene ring or an alicyclic ring. For example, R ₂ may form an unsubstituted or substituted naphthalene ring. Of.

Specific examples of the p-hydroxybenzoic acid ester derivative of the above general formula (A) include 2- (benzenesulfonylamino) ethyl p-hydroxybenzoate and 2- (toluene-4-sulfonyl) p-hydroxybenzoate. amino)
Ethyl, p-hydroxybenzoic acid 2- (toluene-2-
Sulfonylamino) ethyl, p-hydroxybenzoic acid 2
-(4-Ethylbenzenesulfonylamino) ethyl, p-
2- (4-Isopropylbenzenesulfonylamino) ethyl hydroxybenzoate, p-hydroxybenzoic acid 2-
(4-n-propylbenzenesulfonylamino) ethyl,
2- (2,5-Dimethylbenzenesulfonylamino) ethyl p-hydroxybenzoate, p-hydroxybenzoic acid 2
-(2,4,6-Trimethylbenzenesulfonylamino) ethyl, p-hydroxybenzoic acid 2- (4-methoxybenzenesulfonylamino) ethyl, p-hydroxybenzoic acid 2- (4-isopropoxybenzenesulfonylamino)
Ethyl p-hydroxybenzoic acid 2- (naphthalene-1)
-Sulfonylamino) ethyl, p-hydroxybenzoic acid 2- (naphthalene-2-sulfonylamino) ethyl, p-
Hydroxybenzoic acid 2- (5,6,7,8-tetrahydro-
Naphthalene-1-sulfonylamino) ethyl, p-hydroxybenzoic acid 2- (5,6,7,8-tetrahydro-naphthalene-2-sulfonylamino) ethyl, p-hydroxybenzoic acid 2- (4-chlorobenzenesulfonylamino)
Ethyl, p-hydroxybenzoic acid 3- (benzenesulfonylamino) propyl, p-hydroxybenzoic acid 2-
(Benzenesulfonylamino) propyl, p-hydroxybenzoic acid 3- (toluene-4-sulfonylamino) propyl, p-hydroxybenzoic acid 2- (toluene-2-sulfonylamino) propyl, p-hydroxybenzoic acid 3
-(4-Ethylbenzenesulfonylamino) propyl, p
-Hydroxybenzoic acid 2- (4-ethylbenzenesulfonylamino) propyl, p-hydroxybenzoic acid 3- (4
-Isopropylbenzenesulfonylamino) propyl,
2- (4-isopropylbenzenesulfonylamino) propyl p-hydroxybenzoate, 3- (4-n-propylbenzenesulfonylamino) propyl p-hydroxybenzoate, 2- (4-n-propylbenzene) p-hydroxybenzoate Sulfonylamino) propyl, p-hydroxybenzoic acid 3- (2,5-dimethylbenzenesulfonylamino) propyl, p-hydroxybenzoic acid 2- (2,5-
Dimethylbenzenesulfonylamino) propyl, p-hydroxybenzoic acid 3- (2,4,6-trimethylbenzenesulfonylamino) propyl, p-hydroxybenzoic acid 2- (2,4,6-trimethylbenzenesulfonylamino)
Propyl, p-hydroxybenzoic acid 3- (4-methoxybenzenesulfonylamino) propyl, p-hydroxybenzoic acid 2- (4-methoxybenzenesulfonylamino)
Propyl, p-hydroxybenzoic acid 3- (naphthalene-
1-sulfonylamino) propyl, p-hydroxybenzoic acid 2- (naphthalene-1-sulfonylamino) propyl, p-hydroxybenzoic acid 3- (naphthalene-2-sulfonylamino) propyl, p-hydroxybenzoic acid 2
-(Naphthalene-2-sulfonylamino) propyl, p-
Hydroxybenzoic acid 3- (5,6,7,8-tetrahydro-
Naphthalene-1-sulfonylamino) propyl, p-hydroxybenzoic acid 2- (5,6,7,8-tetrahydro-naphthalene-1-sulfonylamino) propyl, p-hydroxybenzoic acid 3- (5,6,7, 8-Tetrahydro-naphthalene-2-sulfonylamino) propyl, p-hydroxybenzoic acid 2- (5,6,7,8-tetrahydro-naphthalene-2-sulfonylamino) propyl, p-hydroxybenzoic acid 3- (4- (Chlorobenzenesulfonylamino)
Propyl, 2- (4-chlorobenzenesulfonylamino) propyl p-hydroxybenzoate and the like can be mentioned.
Among the novel p-hydroxybenzoic acid ester derivatives of the present invention, p-hydroxybenzoic acid 2- (toluene-
4-sulfonylamino) ethyl, p-hydroxybenzoic acid 2- (benzenesulfonylamino) ethyl, p-hydroxybenzoic acid 2- (toluene-2-sulfonylamino) ethyl, p-hydroxybenzoic acid 2- (4-chlorobenzenesulfonyl) Amino) ethyl, 2- (toluene-4-sulfonylamino) propyl p-hydroxybenzoate, p-
2- (Benzenesulfonylamino) propyl hydroxybenzoate, 2- (4-chlorobenzenesulfonylamino) propyl p-hydroxybenzoate and the like are preferable, and more preferably p-hydroxybenzoic acid 2- as shown in the present invention 2. (Toluene-4-sulfonylamino) ethyl,
2- (benzenesulfonylamino) ethyl p-hydroxybenzoate and 2- (4-chlorobenzenesulfonylamino) ethyl p-hydroxybenzoate.

The method for synthesizing the p-hydroxybenzoic acid ester derivative of the present invention is not particularly limited and can be synthesized by any method. Therefore, the specific synthetic method thereof will be described in detail below by taking 2- (toluene-4-sulfonylamino) ethyl p-hydroxybenzoate as an example. First, as a reaction of the first step, about 2-fold equivalent of 2-aminoethanol, equivalent sodium hydroxide, and a small amount of water and acetone to p-toluenesulfonyl chloride were stirred in an ice-cooled flask. Then, an acetone solution of p-toluenesulfonyl chloride is gradually added dropwise. At this time, caution is required because it is accompanied by heat generation. After the reaction is completed, acetone and water are removed and sodium chloride is precipitated. Next, water is added so that sodium chloride is dissolved, the solution is separated, and washed with saline several times. Then, it is neutralized with dilute sulfuric acid so as to be weakly acidic. Wash again with saline to make sure the wash is weakly acidic. Then, a small amount of an appropriate acidic catalyst is added to p-toluenesulfonylaminoethanol obtained in the first reaction using xylene as a solvent, p-hydroxybenzoic acid is added, and the temperature is raised with stirring to 140 to 16
A condensation reaction is performed at 0 ° C., and the produced water is azeotropically removed together with xylene. After completion of the reaction, crystallization with a mixed solution of xylene and isopropyl alcohol, filtration of the crystals, washing with water and drying,
Crystals of the desired product are obtained.

As described above, p-hydroxybenzoic acid, amino alcohols, and sulfonyl halides are used as raw materials for the synthesis of the p-hydroxybenzoic acid ester derivative. The above amino alcohols are not particularly limited as long as they are compounds that share a hydroxyl group and an amino group in the molecule, and specific examples include 2-aminoethanol, 1-amino-2-propanol and 3-amino-1.
-Propanol, 4-amino-1-butanol and the like can be mentioned, and 2-aminoethanol is particularly preferable. Specific examples of the sulfonyl halides include benzenesulfonyl chloride, p-toluenesulfonyl chloride, o
-Toluenesulfonyl chloride, 4-ethylbenzenesulfonyl chloride, 4-isopropylbenzenesulfonyl chloride, 4-n-propylbenzenesulfonyl chloride, 2,5-dimethylbenzenesulfonyl chloride,
2,4,6-trimethylbenzenesulfonyl chloride, 4
-Methoxybenzenesulfonyl chloride, 4-isopropoxybenzenesulfonyl chloride, 1-naphthalenesulfonyl chloride, 2-naphthalenesulfonyl chloride, 4-cyclohexylbenzenesulfonyl chloride,
4-chlorobenzenesulfonyl chloride, 5,6,7,8
-Tetrahydro-naphthalene-1-sulfonyl chloride, 5,6,7,8-tetrahydro-naphthalene-2-sulfonyl chloride and the like. Also, bromide, iodide, etc. can be used in place of the chloride, and in addition,
The compound having a sulfonyl halide group is not particularly limited. Among the sulfonyl halide compounds, p-toluenesulfonyl chloride, benzenesulfonyl chloride and 4-chlorobenzenesulfonyl chloride are particularly preferable.

The heat-sensitive recording material of the present invention 3 basically contains a color developing agent which is a colorless dye and a color developing agent which comprises the above-mentioned p-hydroxybenzoic acid ester derivative as essential components. Of course, various additives such as sensitizers can be contained. The color former is a triarylmethane compound, a diarylmethane compound, a rhodamine-lactam compound, a fluorane compound, an indolylphthalide compound, a divinylphthalide compound, a pyridine compound, a spiro compound, a fluorene compound. , And thiazine compounds. Among these, fluoran compounds are preferable, and especially di-n-butylamino-7- (2'-chlorophenylamino) fluorane, 3
-Dimethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-di-n-butylamino-6-methyl-7
-Anilinofluorane, 3-di-n-pentylamino-
6-methyl-7-anilinofluorane, 3-Nn-propyl-N-methylamino-6-methyl-7-anilinofluorane, 3-Nn-butyl-N-methylamino-
6-methyl-7-anilinofluorane, 3-N-isobutyl-N-methylamino-6-methyl-7-anilinofluorane, 3-N-isobutyl-N-ethylamino-6
-Methyl-7-anilinofluorane, 3-N-isopentyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (2'-methoxyethyl) -N-isobutylamino-6 -Methyl-7-anilinofluorane,
3-N- (3'-ethoxypropyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (3'-methylphenylamino) fluorane, 3-N -Cyclohexyl-N-methylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7-anilinofluorane and the like are preferable.

Further, when it is necessary to further adjust the color development performance and the storage stability such as heat resistance, moisture resistance and plasticizer resistance of the image, one or more other known color developers may be used. . The above-mentioned known developer is not particularly limited and any one can be used, but specifically, 2,2-bis (4-hydroxyphenyl) propane, 4-hydroxy-4′-isopropoxy-diphenyl sulfone, 4,4'-dihydroxy-diphenyl sulfone, 2,4'-dihydroxy-
Diphenyl sulfone, 4,4'-dihydroxy-diphenyl sulfide, 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane, N- (p
-Toluenesulfonyl) carbamoylate-p-cumylphenyl, benzyl p-hydroxybenzoate, bis (3-
Allyl-4-hydroxy-phenyl) sulfone, 4-hydroxy-2 ', 5'-dimethyl-diphenyl sulfone, 2-methyl-4-hydroxy-diphenyl sulfone, 2,4-bis (phenylsulfonyl) phenol, 2,
4-bis (p-methylphenylsulfonyl) phenol,
2,4-bis (phenylsulfonyl) -m-cresol and the like can be mentioned.

The color developer comprising the novel p-hydroxybenzoic acid ester derivative of the present invention may be used alone or in combination, and one or more of the above-mentioned other known color developers may be added to this derivative. Can also be used together. On the other hand, the color former may be used singly or in combination of two or more as required. The mixing ratio of the color former and the color developer in the heat-sensitive recording material is 50 to 50 parts by weight based on 100 parts by weight of the color developer.
It is 800 parts by weight, preferably 100 to 500 parts by weight.

On the other hand, when it is necessary to further improve the color developing sensitivity, a sensitizer can be added and used. The sensitizer, behenic acid, capric acid, octylic acid, stearic acid, isostearic acid, lauric acid, palmitic acid, myristic acid, oleic acid, (nuclear substitution) benzoic acid,
(Nuclear Substitution) Zinc salt of monobasic acid such as salicylic acid, calcium salt, magnesium salt, aluminum salt, and amide compound of said monobasic acid, and anilide compound of said monobasic acid, ethylenebisstearylamide, ethylenebislaurylamide , Β-naphthylbenzyl ether, benzyl 4-benzyloxybenzoate, dibenzyl oxalate, oxalate-di-p-methylbenzyl, oxalate-di-p-chlorobenzyl, bis (4-methylphenyl) carbonate, p-benzyl Biphenyl, m-terphenyl, 1,
2-bis (3-methylphenoxy) ethane, 1,2-bis
(4-Methylphenoxy) ethane, 1,2-diphenoxyethane, diphenyl sulfone, 1,2-bis (3,4-dimethylphenyl) ethane, p-benzyloxybiphenyl, diphenyl carbonate, 1-hydroxy-2-naphthalene Phenyl carboxylate, benzyl 1-hydroxy-2-naphthalenecarboxylate, phenyl 3-hydroxy-2-naphthalenecarboxylate, methylenebenzoate,
Acetoacetic acid anilide, 1,4-bis (2-vinyloxyethoxy) benzene, dimethylphthalate, dibutylphthalate, dibenzyl terephthalate, dibenzoylmethane,
Examples include tosylanilide, benzenesulfonic acid anilide, 4-methylphenoxy-p-biphenyl, p-tolylbiphenyl ether, bis (p-methoxyphenoxyethyl) ether, 1- (2-naphthyloxy) -2-phenoxyethane and the like. These sensitizers can be used alone or in combination, and the addition ratio thereof is 20 to 100 parts by weight of the color former.
It is 800 parts by weight, preferably 50 to 400 parts by weight.

In addition, an antioxidant, a UV absorber, a light resistance stabilizer, a water resistance improver, etc. may be added to the heat-sensitive recording material of the present invention, if necessary, for the purpose of adjusting the storage stability of the image. To 100 parts by weight of coloring agent, 0.05 to 1
0 parts by weight can be used. Further, if necessary, various additives for the purpose of adjusting other performances can be used.

The heat-sensitive recording material is morphologically the p-type recording material of the present invention.
-A thermosensitive color-developing layer consisting of a hydroxybenzoate derivative and a color-developing agent as essential components is formed on the surface of a sheet-shaped support. Examples of the above-mentioned support include normal paper obtained by wet-making natural fibers, synthetic paper, mixed paper of natural fibers and synthetic fibers, various plastic sheets, resin-coated paper, and the like, with paper being particularly preferable. That is, a preferable example of the heat-sensitive recording material is heat-sensitive recording paper. The heat-sensitive recording material can be produced by a known method. Specifically, the developer and the color-developing agent of the present invention are usually used as essential components, and other known developers, sensitizers and various additives are added. Agents, etc., or as required, pigments, metal soaps,
Amides, waxes, dispersants, defoamers, etc. are added, and each of these components is finely pulverized and dispersed in a water solvent containing a water-soluble or water-dispersible binder, and the dispersion is formed into a sheet. It is manufactured by coating on a support and drying. The fine pulverization of each component is basically performed by pulverizing to a particle size of 0.5 to 3 μm using an attritor, a ball mill, a sand mill or the like. As the dispersion method, there are a method of mixing those in which each component is individually dispersed, a method of collectively dispersing, and the like, which is not particularly limited, but the one in which the color developer and the color developer are individually dispersed is mixed. The method is preferred.

Further, the above-mentioned binder is for the purpose of preventing the peeling by binding the constituents to the support when forming the heat-sensitive color forming layer on the support, and specifically, polyvinyl alcohol and modified polyvinyl alcohol. , Methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methoxycellulose, polyacrylic amide, modified polyacrylic amide, starches, gelatin, casein, sodium alginate,
Polymers such as styrene-maleic acid copolymers, styrene-butadiene copolymers, modified styrene-butadiene copolymers, sodium polystyrene sulfonate, sodium polyacrylate, etc. dissolved or dispersed in water Can be used. The above-mentioned pigment is added for the purpose of improving the whiteness of the heat-sensitive recording layer and increasing the amount thereof. Specifically, calcium carbonate, magnesium carbonate, kaolin, silica, titanium oxide, talc, clay, zinc oxide, aluminum hydroxide,
Examples thereof include magnesium sulfate, calcium silicate, magnesium silicate, organic polymer beads and the like. Examples of the metal soaps include metal salts of fatty acids such as zinc stearate, calcium stearate, magnesium stearate and aluminum stearate. Examples of the amides include fatty acid amides such as stearic acid amide and lauric acid amide, ethylenebisstearylamide, and ethylenebislaurylamide. Examples of the waxes include paraffin wax, microcrystalline wax, polyethylene wax, sasol wax, carnauba wax, montan wax and the like. As the dispersant, known surfactants can be used, and fatty acid salts, alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ethers. Anionic surfactants such as disulfonates, alkyl phosphates, naphthalene sulfonic acid formalin condensates, and polycarboxylic acid type polymer surfactants can be mentioned.
In addition, known nonionic surfactants and cationic surfactants can also be used.

As described above, the heat-sensitive recording material can be obtained by coating the surface of the sheet with the dispersion liquid which constitutes the heat-sensitive color forming layer and drying it. The coating method on the sheet is basically a method of applying a dispersion liquid comprising a thermosensitive coloring layer to the sheet,
An impregnation method in which the sheet is immersed in the dispersion liquid may be used, or a spraying method using a spray or the like may be used. The coating method is not particularly limited, and conventionally known techniques such as an air knife coater, a bar coater, a roll coater, a blade coater, and a curtain coater can be used. The coating amount on the sheet is not particularly limited, but is preferably about ² to 10 g / m ² . On the other hand, in the heat-sensitive recording material, an undercoat layer may be provided on the support before forming the heat-sensitive color forming layer in order to improve the color forming sensitivity. In addition, a protective layer may be provided on the surface of the heat-sensitive recording layer in order to enhance storage stability and improve appearance. Further, if necessary, a printing layer may be provided on the surface of the thermosensitive coloring layer, or a natural rubber adhesive, an acrylic adhesive, styrene-
It is also possible to provide an adhesive layer of a synthetic rubber adhesive such as a butadiene-based or styrene-isoprene-based block copolymer.

[0032]

As described above, a heat-sensitive recording material using a known developer such as benzyl p-hydroxybenzoate and bisphenol A has the advantages of high sensitivity and high color density, but has the disadvantage of producing a color image. There is a problem that storage stability is poor and whitening and fading easily occur, but as will be apparent from the test examples described below, when the p-hydroxybenzoic acid ester derivative of the present invention is used as a developer for heat-sensitive recording, Although the mechanism is not clear, the presence of a sulfonylamino group in the molecule in addition to the basic p-hydroxybenzoic acid ester skeleton maintains the coloring sensitivity and coloring density comparable to those of the above-mentioned known developers. However, it has less background fog and is excellent in image storage stability such as heat resistance and plasticizer resistance. That is, the novel p-hydroxybenzoic acid ester derivative of the present invention has a remarkable superiority in storage stability of images as compared with conventionally known color developers.
It is highly practical as a developer for heat-sensitive recording. Further, the p-hydroxybenzoic acid ester derivative of the present invention can be expected to have biodegradability, and is promising as a developer for heat-sensitive recording with little environmental pollution. Furthermore, since the p-hydroxybenzoic acid ester derivative of the present invention has a p-hydroxybenzoic acid skeleton, it can be expected to be used as a bactericide.

[0033]

EXAMPLES Synthesis examples of the p-hydroxybenzoic acid ester derivative of the present invention, production examples of heat-sensitive recording paper containing the derivative, and color-developing performance test examples of the heat-sensitive recording paper will be sequentially described below. "%" And "part" shown in Examples and Test Examples
Is basically on a weight basis. The present invention is not limited to the following examples and test examples, and it goes without saying that any modifications can be made within the scope of the technical idea of the present invention.

<< Synthesis Example of p-Hydroxybenzoic Acid Ester Derivative >> (a) Synthesis Example 1 Monoethanolamine 12 was used as the first step reaction step.
A flask was charged with 2 g, 40 g of sodium hydroxide, a small amount of water and acetone. 190 g of tosyl chloride dissolved in acetone was gradually added dropwise with stirring under ice cooling. After reacting for 3 hours, acetone and water were removed by an evaporator to precipitate sodium chloride. Then, water to the extent that sodium chloride was dissolved was added, the solution was separated, washed twice with saline, and then neutralized with dilute sulfuric acid to make it weakly acidic. The layers were separated and washed again with saline, and it was confirmed that the washing solution was weakly acidic. Then, as a reaction step of the second step, xylene is added to the product of the first step and p as a catalyst.
-Toluenesulfonic acid was added in a small amount, 69 g of p-hydroxybenzoic acid was added, the temperature was raised with stirring, the condensation reaction was performed at 150 ° C, and the produced water was azeotropically removed together with xylene. After completion of the reaction for 8 hours, xylene and isopropyl alcohol were added, and after crystallization, filtration and washing with water were performed. After drying, 103 g of white crystals were obtained.

About the obtained crystals, melting point, IR, NM
When R was measured, it was as follows. (1) Melting point 122.8 ° C to 123.3 ° C The melting point was measured according to JIS K 0064. (2) IR (KBR) (cm ^-1 ) 3392, 3299, 1922, 1705, 1608,
1592, 1514, 1445, 1390, 1279,
1215, 1158, 1093, 1033, 950, 8
53,817,771,670,550. Particularly, 3392 and 3299 cm ⁻¹ are considered to be absorption peaks of hydroxyl group and sulfonylamino group, and 1324 and 1158 cm ⁻¹ are considered to be absorption peaks of sulfonylamino group. (3) ¹³ C-NMR ((CD ₃ ) ₂ SO) δ value (ppm) 21.0, 41.7, 63.0, 115.3, 120.3
126.5, 129.7, 131.8, 137.9, 14
2.7, 162.1, 165.5. From the above results, it was confirmed that the obtained compound was 2- (toluene-4-sulfonylamino) ethyl p-hydroxybenzoate.

(B) Synthesis Example 2 Monoethanolamine 122 was used as the first step reaction.
g, 40 g of sodium hydroxide, a small amount of water and acetone were charged to the flask. While stirring under ice cooling, 176 g of benzenesulfonyl chloride was gradually added dropwise. After reacting for 3 hours, remove acetone and water with an evaporator,
Sodium chloride was precipitated. Then, water to the extent that sodium chloride was dissolved was added, the layers were separated, and washed twice with saline. Then, it was neutralized with dilute sulfuric acid so as to be weakly acidic. The layers were separated and washed again with saline, and it was confirmed that the washing solution was weakly acidic. Then, as a second-step reaction step, xylene is added to the first-step reaction product and p as a catalyst.
-Toluenesulfonic acid was added in a small amount, 69 g of p-hydroxybenzoic acid was added, the temperature was raised with stirring, the condensation reaction was carried out at 150 ° C, and the produced water was azeotropically removed together with xylene. After completion of the reaction for 8 hours, xylene and isopropyl alcohol were added, and after crystallization, filtration and washing with water were performed. After drying, 77 g of white crystals were obtained.

About the obtained crystals, melting point, IR, NM
When R was measured, it was as follows. (1) Melting point 152.5 ° C to 153.2 ° C (2) IR (KBR) (cm ^-1 ) 3321, 3262, 1681, 1607, 1588,
1514, 1430, 1392, 1314, 1291,
1224, 1159, 1133, 1091, 1027,
968,850,770,754,727,595,5
69. Particularly, 3321 and 3262 cm ⁻¹ are considered to be absorption peaks of hydroxyl group and sulfonylamino group, and 1314 and 1159 cm ⁻¹ are considered to be absorption peaks of sulfonylamino group. (3) ¹³ C-NMR ((CD ₃ ) ₂ SO) δ value (ppm) 41.6, 62.9, 115.2, 120.1, 126.
4,129.2,131.7,132.4,140.7,1
62.0, 165.4. From the above results, it was confirmed that the obtained compound was 2- (benzenesulfonylamino) ethyl p-hydroxybenzoate.

(C) Synthesis Example 3 Monoethanolamine 122 was used as the first step reaction.
g, 40 g of sodium hydroxide, a small amount of water and acetone were charged to the flask. 4-chlorobenzenesulfonyl chloride 21 dissolved in acetone while stirring under ice cooling
1 g was gradually added dropwise. After reacting for 3 hours, it was neutralized with dilute sulfuric acid so as to be weakly acidic. Then, acetone was removed by an evaporator to deposit a first-step reaction product, and crystals were separated by filtration. Then, as a second-step reaction step, xylene and a small amount of p-toluenesulfonic acid as a catalyst were added to the crystals separated by filtration, 69 g of p-hydroxybenzoic acid was added, and the temperature was raised with stirring at 150 ° C. A condensation reaction was performed, and the produced water was azeotropically removed together with xylene. After reaction for 8 hours,
After adding xylene and isopropyl alcohol and crystallization,
It was filtered and washed with water. After drying, 133 g of white crystals were obtained.

The melting point, IR, and NMR of the obtained crystal were measured in the same manner as in Synthesis Example 1, and the results were as follows. (1) Melting point 149.5 ° C to 150.5 ° C (2) IR (KBR) (cm ^-1 ) 3263, 1914, 1685, 1610, 1588,
1514, 1473, 1461, 1334, 1283
1232, 1155, 1089, 1012, 991, 9
04,850,829,768,755,698,62
3,559. Particularly, 3263 cm ⁻¹ is considered to be the absorption peak of hydroxyl group and sulfonylamino group, and 1334 and 1155 cm ⁻¹ is considered to be the absorption peak of sulfonylamino group. (3) ¹³ C-NMR ((CD ₃ ) ₂ SO) δ value (ppm) 41.6, 62.8, 115.2, 120.1, 128.
3,129.3,131.6,137.3,139.6,1
62.0, 165.4. From the above results, it was confirmed that the obtained compound was 2- (4-chlorobenzenesulfonylamino) ethyl p-hydroxybenzoate.

Therefore, each p obtained in the above Synthesis Examples 1 to 3 is
Examples of production of heat-sensitive recording paper using a hydroxybenzoic acid ester derivative as a color developer will be sequentially described. Example 1 (1) Preparation of Basic Dye Dispersion Liquid 20 g of 3-N, N-dibutylamino-6-methyl-7-anilinofluorane was added to polyvinyl alcohol having a concentration of 5%.
(Kuraray Co., Ltd .; trade name PVA-117) was pulverized for 20 hours using a ball mill in 80 g of an aqueous solution to prepare a basic dye dispersion liquid (that is, a color developer dispersion liquid) having an average particle diameter of 1.0 μm. did. (2) Preparation of Developer Dispersion Liquid 120 g of an aqueous solution containing 80 g of 2- (toluene-4-sulfonylamino) ethyl p-hydroxybenzoate of Synthesis Example 1 above, 6 g of methyl cellulose and 0.1 g of sodium dioctylsulfosuccinate. And finely pulverized with a ball mill for 10 hours to obtain an aqueous dispersion of a color developer having an average particle diameter of 1.0 μm. (3) Preparation of sensitizer 60 g of β-naphthylbenzyl ether was added to a 140% aqueous solution of polyvinyl alcohol (PVA-117) having a concentration of 5%.
The powder was finely pulverized for 20 hours in a ball mill using a ball mill to prepare a sensitizer dispersion having an average particle size of 1.0 μm. (4) Preparation of Lubricant Dispersion Liquid 80 g of zinc stearate as a lubricant, 6 g of methyl cellulose and 0.1 g of sodium dioctylsulfosuccinate.
Wet it with 320 g of an aqueous solution containing 1 g, and rotate at 3,
The mixture was stirred with a homogenizer at 000 rpm for 2 hours to prepare a zinc stearate dispersion liquid having an average particle diameter of 5.5 μm. (5) Preparation of Thermosensitive Coloring Layer Coating Liquid 3 g of the above basic dye dispersion, 3 g of developer dispersion, 4 g of sensitizer dispersion, 60% concentration of calcium carbonate (trade name TP-123CS manufactured by Okutama Kogyo Co., Ltd.) 3.5 g of the dispersion of 1), 3.0 g of the zinc stearate dispersion, and 7.4 g of water were mixed to obtain a thermosensitive color developing layer coating solution. (6) Production of thermosensitive recording paper The coating amount of the thermosensitive coloring layer after drying is 5 g / m ² on high-quality paper.
So that the thermosensitive coloring layer coating solution is applied using a wire bar and dried in an oven at 60 ° C. to obtain a smoothness of 2
The heat-sensitive recording paper of Example 1 was prepared by calendering so that it would be 00 seconds (Beck method).

Example 2 Based on the production method of Example 1 above, instead of Synthesis Example 1, 2- (benzenesulfonylamino) ethyl p-hydroxybenzoate of Synthesis Example 2 was used as a developer. A thermal recording paper was prepared in the same manner as in Example 1 except for the above.

Example 3 Based on the production method of Example 1 above, instead of Synthesis Example 1, p-hydroxybenzoic acid 2- (4-chlorobenzenesulfonylamino) of Synthesis Example 3 was used.
A thermosensitive recording paper was prepared in the same manner as in Example 1 except that ethyl was used as the color developer.

Example 4 Based on the production method of Example 1 above, 1,2-bis (3-methylphenoxy) was used as the sensitizer in place of the β-naphthylbenzyl ether used in Example 1. ) A thermal recording paper was prepared in the same manner as in Example 1 except that ethane was used.

Example 5 On the basis of the production method of Example 1 described above, oxalic acid-di-p- was used as the sensitizer instead of the β-naphthylbenzyl ether used in Example 1.
A thermal recording paper was prepared in the same manner as in Example 1 except that methylbenzyl was used.

Example 6 Based on the production method of Example 1 above, except that p-benzylbiphenyl was used as the sensitizer in place of the β-naphthylbenzyl ether used in Example 1, A thermal recording paper was prepared in the same manner as in Example 1.

Example 7 Based on the production method of Example 1 above, except that m-terphenyl was used as the sensitizer in place of the β-naphthylbenzyl ether used in Example 1, except that A thermal recording paper was prepared in the same manner as in Example 1.

Comparative Example 1 Based on the production method of Example 1 described above, p- which is a known developer, instead of Synthesis Example 1, was used.
Example 1 except that benzyl hydroxybenzoate was used
The same procedure was followed to prepare a thermosensitive recording paper.

Comparative Example 2 Based on the production method of Example 1 above, instead of Synthesis Example 1, a known developer, 2,
A thermal recording paper was prepared in the same manner as in Example 1 except that 2-bis (4-hydroxyphenyl) propane was used.

Therefore, the above Examples 1 to 7 and Comparative Examples 1 to
Using each thermosensitive recording paper obtained in 2, the print density and background density during color development were measured, and a storage stability test of heat resistance and plasticizer resistance was performed. << Example of color development performance test of thermosensitive recording paper >> Each of the thermosensitive recording papers of Examples 1 to 7 and Comparative Examples 1 and 2 was subjected to a thermal inclination tester (manufactured by Toyo Seiki Co., Ltd.).
Then, the color was developed under the conditions of a heat plate temperature of 140 ° C. and a printing time of 0.5 seconds, and the print density and background density at the time of color development were measured using a Macbeth densitometer. In addition, as a heat resistance test, the thermosensitive recording paper after color development was left under conditions of 60 ° C and 48 hours, and the image density and background density were measured with a Macbeth densitometer. Was examined over time. Further, as a plasticizer resistance test, a thermosensitive recording paper after coloring was wrapped around the outer periphery of a glass bottle, and a soft vinyl chloride resin film (Mitsui Chemicals Co .; trade name Hilap V-450) was wrapped around it in a triple layer at 40 ° C. After leaving it for 3 hours, the image density after storage was measured with a Macbeth densitometer to evaluate the durability against the plasticizer.

FIG. 1 shows the result. The novel p of the present invention
Examples 1 to 7 in which the hydroxybenzoic acid ester derivative was used retained a level comparable to Comparative Examples 1 and 2 in which a known color developer was used, in terms of printing density at the time of color development. . Looking at the heat-resistant storage stability of the printed portion, the densities after heating and leaving in Comparative Examples 1 and 2 were almost halved as compared with the time of color development, whereas the density reductions in Examples 1 to 7 were small and were high. The print density was secured. From the heat-resistant storage stability of the background portion, it was found that Examples 1 to 7 had almost no background stain as compared with Comparative Examples 1 and 2. Regarding the plasticizer resistance, the print densities of Comparative Examples 1 and 2 are around 0.5, while those of Examples 1 to 7 are all 0.7 or more, and particularly, Examples 1 and 4 to 7 are It showed a high level exceeding 0.8. As described above, when the p-hydroxybenzoic acid ester derivative of the present invention is used as a color developer, the color density and color sensitivity are comparable to those of known color developers such as p-hydroxybenzoic acid ester and bisphenol A. It was revealed that there is no stain, and there is little background stain, and that the storage stability such as heat resistance and plasticizer resistance, which are often problematic with known developers, can be significantly improved.

[Brief description of drawings]

FIG. 1 is a chart showing the color development performance test results of thermal recording papers of Examples 1 to 7 and Comparative Examples 1 and 2.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akira Sanada             4 No. 671 Mizusui, Noguchi Town, Kakogawa City, Hyogo Prefecture             Harima Kasei Co., Ltd. (72) Inventor Ryoichi Fujii             4 No. 671 Mizusui, Noguchi Town, Kakogawa City, Hyogo Prefecture             Harima Kasei Co., Ltd. (72) Inventor Torasuke Saito             4 No. 671 Mizusui, Noguchi Town, Kakogawa City, Hyogo Prefecture             Harima Kasei Co., Ltd. F-term (reference) 2H026 AA07 BB26                 4H006 AA01 AA03 AB99

Claims (3)

[Claims] 1. A compound represented by the following general formula (A): (In the formula (A), R ₁ is a C ₂ -C ₄ alkylene group; R ₂ is an unsubstituted benzene ring, or one of an alkyl group, a phenyl group, a cycloalkyl group, an alkoxyl group, a halogen atom, or Two or more are benzene rings substituted with 1 to 4. However, when R ₂ is the substituted benzene ring, adjacent substituents may be bonded to each other to further form a benzene ring or an alicyclic ring. ) A novel p-hydroxybenzoic acid ester derivative having a sulfonylamino group in the molecule. 2. 2- (Toluene-4-sulfonylamino) ethyl p-hydroxybenzoate, 2- (benzenesulfonylamino) ethyl p-hydroxybenzoate, 2- (4-chlorobenzenesulfonylamino) p-hydroxybenzoate A novel p-hydroxybenzoic acid ester derivative selected from the group consisting of ethyl. 3. A heat-sensitive recording material containing a color-developing agent and a color-developing agent, wherein the color-developing agent is the p-hydroxybenzoic acid ester derivative according to claim 1 or 2.