JPH09109551A - Heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve stability and storing properties of a recording image by using a carboxylic acid of formula as a color developing agent for developing a leuco dye on a substrate when it is heated. SOLUTION: In a heat-sensitive recording material with a heat-sensitive color developing layer wherein a leuco dye and a color developing agent for developing the leuco dye in heating are main ingredients, as the color developing agent, a carboxylic acid compd. of formula I is used. In the formula I, n is an integer of 1-3, R1 is a hydroxide group, an alkyl group, an alkoxy group, a halogen group or a hydrogen atom and R2 is an aliph. hydrocarbon group. In addition, X is a divalent group of formula II, wherein p and q are respectively integer of 0 or 1 and A is a divalent aliph. hydrocarbon group and B is a divalent aliph. hydrocarbon group or an arom. hydrocarbon group which may have a substd. group. In addition, Y and Z are respectively a divalent group contg. at least one heteroatom and they may be the same or different from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material, and more particularly to a heat-sensitive recording material having excellent storage stability of recorded images.

[0002]

2. Description of the Related Art In general, various recording materials have been proposed which utilize a color-forming reaction by heat, pressure or the like between a colorless or pale-colored electron-donating substance (leuco dye) and a developer which forms a color when the dye is contacted. ing. One such thermal recording material is
Published in various publications such as JP-B-43-4160, JP-B-45-14039 and JP-A-48-27736, it is not necessary to perform frequent processing such as development and fixing, and it is a relatively simple apparatus. Due to its advantages such as being able to record in a short time, generating less noise, and being inexpensive, it is widely used as various recording materials for electronic computers, facsimile machines, ticket vending machines, label printers, recorders, and the like.

Color-forming dyes used in heat-sensitive recording materials include, for example, colorless or light-colored leuco dyes having a lactone, lactam or spiropyran ring, and conventional developers include organic acids and phenolic substances. ing. The heat-sensitive recording material using this leuco dye and a developer,
It is widely used because of its high image density and high whiteness of the background. On the other hand, as the demand for the thermal recording system has increased in recent years, there has been an increasing demand for improvement in the preservability of recording chemicals, light, heat, water, etc., and there is a strong demand for the development of recording materials that can meet this demand. It is rare. Heretofore, in order to cope with high storage stability of recorded images, a phenol sulfone compound has been used as a highly reliable developer, for example, in JP-A-58-82788 and JP-A-60-13852. JP-A-61-47292 discloses a metal salt of benzoic acid, and JP-A-62-169681 proposes a substituted salicylic acid compound. A heat-sensitive recording material using these compounds as a developer. Is still insufficient in terms of the fastness of the image part to water and the like.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has as its object to provide a heat-sensitive recording material having high stability of recorded images and excellent storability. I do.

[0005]

According to the present invention, there is provided a heat-sensitive recording material having a heat-sensitive color-forming layer containing, as a main component, a leuco dye and a color developing agent for developing the leuco dye upon heating. A heat-sensitive recording material is provided, wherein a carboxylic acid compound represented by the following general formula (1) is used as a developer.

[0006]

Embedded image

However, n in the formula represents an integer of 1 to 3,
R ₁ represents a hydroxyl group, an alkyl group, an alkoxy group, a halogen group or a hydrogen atom, and R ₂ represents an aliphatic hydrocarbon group. X represents a divalent group represented by the following general formula (2). -(A) _p -Y- (B) _q -Z- (2) (In the formula, p and q each represent an integer of 0 or 1, and A
Represents a divalent aliphatic hydrocarbon group, and B represents a divalent aliphatic hydrocarbon group or aromatic hydrocarbon group which may have a substituent. Y and Z each represent a divalent group containing at least one hetero atom, which may be the same or different. ) Specific examples of the compound represented by the general formula (1) used in the present invention include those shown in Table 1 below.
The present invention is not limited to these.

[0008]

Embedded image

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

[Table 3]

[0012]

[Table 4]

[0013]

[Table 5]

[0014]

[Table 6]

[0015]

[Table 7]

[0016]

[Table 8]

[0017]

[Table 9]

[0018]

[Table 10]

[0019]

[Table 11]

[0020]

[Table 12]

[0021]

[Table 13]

[0022]

[Table 14]

[0023]

[Table 15]

[0024]

[Table 16]

[0025]

[Table 17]

[0026]

[Table 18]

[0027]

[Table 19]

[0028]

[Table 20]

[0029]

[Table 21]

[0030]

[Table 22]

[0031]

[Table 23]

[0032]

[Table 24]

[0033]

[Table 25]

[0034]

[Table 26]

[0035]

[Table 27]

[0036]

[Table 28]

[0037]

[Table 29]

[0038]

[Table 30]

[0039]

[Table 31]

[0040]

[Table 32]

[0041]

[Table 33]

[0042]

[Table 34]

[0043]

[Table 35]

[0044]

[Table 36]

[0045]

[Table 37]

[0046]

[Table 38]

[0047]

[Table 39]

[0048]

[Table 40]

[0049]

[Table 41]

[0050]

[Table 42]

[0051]

[Table 43]

[0052]

[Table 44]

[0053]

[Table 45]

[0054]

[Table 46]

[0055]

[Table 47]

[0056]

[Table 48]

[0057]

[Table 49]

[0058]

[Table 50]

The leuco dye used in the present invention includes
In general, leuco dyes known in this type of leuco recording material are used alone or in combination of two or more kinds.
Triphenylmethanephthalide type, triallylmethane type,
Fluoran series, phenothiazine series, thiofluorane series,
Leuco compounds of dyes such as xanthene type, indophthalyl type, spiropyran type, azaphthalide type, chromenopyrazole type, methine type, rhodamine anilinolactam type, rhodamine lactam type, quinazoline type, diazaxanthene type and bislactone type are preferably used. . Specific examples of such leuco dyes include those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluorane, 3 -Dimethylamino-5,
7-Dimethylfluorane, 3- (N-methyl-N-isoamylamino) -6-methyl-7-anilinofluorane, 3- (N-methyl-N-isobutylamino) -6-
Methyl-7-anilinofluorane, 3- (Np-tolyl-N-ethylamino) -6-methyl-7-anilinofluorane, 3- (N-methyl-N-amylamino) -6
-Methyl-7-anilinofluorane, 3- (N, N-di-n-amylamino) -6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexylamino) -6- Methyl-7-anilinofluorane, 3- (N
-Methyl-N-iso-propylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-Ni)
so-propylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane,
3-diethylamino-7,8-benzfluoran, 3-
Diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-
6-methyl-7-chlorofluorane, 3-pyrrolidino-
6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (m-trichloroanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutylamino-7- (O-chloroanilino) fluorane, 3-diethylamino-6-
Methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino) fluorane, 3- (N, N-diethylamino)-
5-methyl-7- (N, N-dibenzylamino) fluorane, benzoylleucomethylene blue, 6'-chloro-8'-methoxybenzoindolinospiropyran, 6 '
-Bromo-8'-methoxybenzoindolinospiropyran, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-chlorophenyl) phthalide, 3- (2'-hydroxy -4'-Dimethylaminophenyl) -3- (2'-methoxy-5'-nitrophenyl) phthalide, 3- (2'-hydroxy-
4'-dimethylaminophenyl) -3- (2'-methoxy-5'-methylphenyl) phthalide, 3- (2'-methoxy-4'-dimethylaminophenyl) -3- (2 '
-Hydroxy-4'-chloro-5'-methylphenyl)
Phthalide, 3-morpholino-7- (N-propyltrifluoromethylanilino) fluorane, 3-pyrrolidino-
7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-
7- (di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluorane, 3- (N-ethyl-N)
-P-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-methoxycarbonylphenylethyl) fluorane, 3-diethylamino-5-methyl-7- (α-phenylethylamino) Fluorane, 3-diethylamino-7-piperidinoaminofluorane, 2-chloro-3- (N-methyltoluidino) -7- (p-N-butylanilino) fluorane, 3,6-bis (dimethylamino) fluorenspyro ( 9,3 ')-6'-Dimethylaminophthalide, 3-
(N-ethyl-N-cyclohexylamino) -5,6-
Benzo-7-α-naphthylamino-4′-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3- (N-ethyl-N-2-ethoxypropylamino) -6-methyl -7- Anilino Fluoran,
3- (N-ethyl-N-tetrafurfurylamino) -6
-Methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino-4 ', 5'-benzofluorane, 3- (p-dimethylaminophenyl) -3
-{1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} phthalide, 3- (p-dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2 -Yl} -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3-
(1-p-Dimethylaminophenyl-1-phenylethylene-2-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-
1-p-chlorophenylethylene-2-yl) -6-dimethylaminophthalide, 3- (4'-dimethylamino-
2'-methoxy) -3- (1 "-p-dimethylaminophenyl-1" -p-chlorophenyl-1 ", 3" -butadiene-4 "-yl) benzophthalide, 3- (4'-dimethylamino-2) '-Benzyloxy) -3- (1 "-
p-dimethylaminophenyl-1 "-phenyl-1",
3 "-butadiene-4" -yl) benzophthalide, 3-
Dimethylamino-6-dimethylamino-fluorene-9
-Spiro-3 '-(6'-dimethylamino) phthalide,
3,3-bis {2- (p-dimethylaminophenyl)-
2- (p-methoxyphenyl) ethenyl} -4,5,
6,7, tetrachlorophthalide, 3-bis {1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl}-
5,6-dichloro-4,7-dibromophthalide, bis (p-dimethylaminostyryl) -1-naphthalenesulfonylmethane, bis (p-dimethylaminostyryl)-
1-p-tolylsulfonylmethane and the like.

In the present invention, the carboxylic acid compound represented by the above-mentioned general formula (1) is used as the color developer, and if necessary, other electron-accepting compounds,
For example, phenolic compounds, thiophenolic compounds,
A thiourea derivative, an organic acid and a metal salt thereof can be used in combination, and specific examples thereof include, but are not limited to, those shown below.

4,4'-isopropylidene diphenol, 4,4'-isopropylidene bis-o-methyl phenol, 4,4'-sec-butylidene bisphenol, 4,4'-isopropylidene bis (2-tert) −
Butylphenol), zinc p-nitrobenzoate, 1,
3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzylisocyanuric acid, 2,2
-(3,4'-dihydroxyphenyl) propane, bis (4-hydroxy-3-methylphenyl) sulfide,
4- (β- (p-methoxyphenoxy) ethoxy) salicylic acid, 1,7-bis (4-hydroxyphenylthio)
-3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane, monobenzyl phthalate monocalcium salt, 4,4′-cyclohexylidene diphenol, 4,4 ′ -Isopropylidenebis (2-chlorophenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-2-methylphenol), 1, 1,3-Tris (2
-Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-diphenol sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone,
4-benzyloxy-4'-hydroxydiphenyl sulfone, 4,4'-diphenol sulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis (4-hydroxyphenylthio) propane, N, N '
-Diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicylanilide, methyl bis (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, 1,3-bis (4- Hydroxyphenyl) benzene, 1,4-bis (4-hydroxyphenyl) benzene, 2,4′-diphenolsulfone,
3,3'-diallyl-4,4'-hydroxyphenyl sulfone, 3,4-dihydroxy-4'-methyldiphenyl sulfone, zinc 1-acetyloxy-2-naphthoate, zinc 2-acetyloxy-3-naphthoate , Zinc 3-acetyloxy-1-naphthoate, α, α-bis (4
-Hydroxyphenyl) -α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4'-
Thiobis (2-methylphenol), 4,4′-thiobis (2-chlorophenol) and the like.

In order to obtain the heat-sensitive recording material of the present invention, a heat-sensitive color forming layer containing a leuco dye, a color developer and a late auxiliary component may be provided on the support, and various conventional binders may be used as the binder. Can be used as appropriate. Specific examples of such a binder include the following.
Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylic ester copolymer, acrylamide / acrylic ester / methacrylic Acid terpolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein, and other water-soluble polymers, as well as polyvinyl acetate , Emulsions such as polyurethane and polyvinyl acetate copolymer, and latex such as styrene / butadiene / acrylic copolymer.

Further, in the present invention, various heat-fusible substances can be used in combination as the sensitivity improving agent, and specific examples thereof include the followings, but the present invention is not limited thereto. . Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate and zinc behenate, p-benzyl Biphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, phenyl β-naphthoate, 1-hydroxy-
Phenyl 2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, guaiacol carbonate, dibenzyl terephthalate, dimethyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-di Benzyloxynaphthalene, 1,2-diphenoxyethane, 1,2-bis (3-
Methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-diphenoxybutane,
1,4-diphenoxy-2-butene, 1,2-bis (4
-Methoxyphenylthio) ethane, dibenzoylmethane, 1,4-diphenylthiobutane, 1,4-diphenylthio-2-butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2-vinyloxyethoxy) biphenyl, p-aryloxybiphenyl, p-
Propagyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyl disulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, P-benzyloxybenzyl alcohol, 1,3-phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, 1,2
-Bis (4-methoxyphenoxy) propane, 1,5-
Bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, bis (4-methylbenzyl) oxalate, bis (4-chlorobenzyl) oxalate and the like.

When a heat-sensitive recording material is obtained, if necessary, an additive component commonly used in this kind of heat-sensitive recording material, for example, a filler, a surfactant, a lubricant, a pressure color-developing preventing agent or the like can be used in combination. . In this case, as the filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin,
Inorganic fine powders such as talc and surface-treated calcium and silica, as well as organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin and vinylidene chloride resin can be mentioned. Examples of the lubricant include higher fatty acids and metal salts thereof, higher fatty acid amides, higher fatty acid esters, and various animal, vegetable, mineral or petroleum waxes. Further, in the present invention, if necessary, an intermediate layer may be provided between the support and the thermosensitive coloring layer, and the above-mentioned various fillers, expandable and non-expandable fine hollow particles and the like together with the binder and the like, It may be bonded and supported to form an intermediate layer.

[0066]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to Examples and Comparative Examples. Examples 1 to 3 A mixture having the following composition was separately dispersed in a lath mayonnaise bottle using a glass ball for 2 days in a ball mill to prepare [solution A], [solution B] and [solution C]. did. [Liquid A] 3-N, N-dibutylamino-6-methyl-7-anilinofluoran 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts [Liquid B] Developer shown in Table 2 20 parts polyvinyl alcohol 10% aqueous solution of 20 parts Water 60 parts [C liquid] Silicon dioxide 20 parts Water 60 parts Next, [A liquid] 10 parts, [B liquid] 30 parts, [C liquid] 10
Was mixed with 10 parts of a zinc stearate dispersion (concentration: 30%) to obtain a thermosensitive coloring layer forming liquid. This heat-sensitive color forming layer-forming liquid was applied and dried on the surface of a commercially available high-quality paper (basis weight: 53 g / m ² ) so that the amount of dye adhering after drying was 0.5 g / m ² to form a heat-sensitive color forming layer. Next, the surface smoothness is 500
The surface of the layer was calendered for about 600 seconds to prepare the heat-sensitive recording material of the present invention.

Comparative Example A thermosensitive recording material was prepared in the same manner as in Example 1 except that the following [Solution E] was used instead of [Solution B] in Examples 1 to 3. [Solution E] 4,4′-dihydroxydiphenyl sulfone 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts The heat-sensitive recording material obtained as described above was 2 kg / cm ² for 1 second in a heat block of 150 ° C. Printing was performed under the conditions, and a water resistance test was performed on each printed sample. Table 2 shows the results. The test conditions are as follows, and the measurement of color density and background density is the same as above.

<Water resistance test> Density of the background part and the colored part after the test sample was immersed in tap water for 16 hours

[0069]

[Table 51]

[0070]

The heat-sensitive recording material using the carboxylic acid compound represented by the formula (1) of the present invention as a developer has a high storage stability of recorded images and exhibits particularly excellent water resistance.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kyoji Tsutsui 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (2)

[Claims] 1. A thermosensitive recording material having a thermosensitive color developing layer, which comprises a leuco dye and a developer which develops a color when the leuco dye is heated, as a main component on a support. ) A heat-sensitive recording material comprising a carboxylic acid compound represented by Embedded image However, n in the formula represents an integer of 1 to 3, R ₁ represents a hydroxyl group, an alkyl group, an alkoxy group, a halogen group or a hydrogen atom, and R ₂ represents an aliphatic hydrocarbon group. X represents a divalent group represented by the following general formula (2). -(A) _p -Y- (B) _q -Z- (2) (In the formula, p and q each represent an integer of 0 or 1, and A
Represents a divalent aliphatic hydrocarbon group, and B represents a divalent aliphatic hydrocarbon group or aromatic hydrocarbon group which may have a substituent. Y and Z each represent a divalent group containing at least one hetero atom, which may be the same or different. ) 2. The heat-sensitive recording material according to claim 1, wherein X in the formula (1) is a group represented by the following formula (3). Embedded image