JPH04185486A - Thermosensitive recording material - Google Patents

Abstract

PURPOSE:To obtain a thermosensitive recording material capable of developed color density and excellent preservability of a recorded image part by using a specified phenol compound as a developer. CONSTITUTION:A phenol compound expressed by formula I is used as a developer and further, various electron-receptive compounds are jointly used, if necessary to prepare a thermosensitive coloring layer formation liquid. Then this liquid is applied to a high quality paper and this coat is dried to obtain a thermosensitive coloring layer. In addition, the layer surface is calendered to prepare a thermosensitive recording material. This recording material obtained demonstrates an adequate coloring density and an excellent safety and stability over the image and texture parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-sensitive recording material, and particularly to a heat-sensitive recording material with excellent storage stability.

[Conventional technology]

Heat between a colorless or light-colored leuco dye and a color developer,
Various recording materials have been proposed that utilize color reactions caused by pressure or the like.

One type of thermal recording material is that it does not require complicated processing such as development and fixing, can be recorded in a short time using relatively simple equipment, generates little noise, and is low in cost. Due to computer, facsimile,
It is useful as a variety of recording materials for ticket vending machines, labels, recorders, etc.

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 organic acids, phenolic substances, and the like have been conventionally used as color developers. Recording materials using this leuco dye and color developer are widely used because of their high image density and high background whiteness.

On the other hand, as the demand for thermal recording methods has increased in recent years, the demand for preservation quality of recorded images has increased. For this reason, there is a strong desire not only to increase the speed of the recording apparatus itself, but also to develop heat-sensitive recording materials that can handle this.

[Problem to be solved by the invention]

As a highly sensitive color developer, for example, JP-A-56-144193
P-hydroxybenzoic acid ester has been proposed in Japanese Patent Publication No. 59-22793, etc., and hydroxynaphthoic acid ester has been proposed in Japanese Patent Application Laid-Open No. 59-22793, etc., but heat-sensitive recording materials using these compounds have problems with the storage stability of the image area. have Furthermore, JP-A-59
JP-A-165680 proposes the use of a thioester compound as a color developer, but recording materials using this compound have a drawback of low sensitivity, although the fastness to oils and fats in the image area is high.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material with sufficient color density and good storage stability in recorded image areas.

[Means to solve the problem]

According to the present invention, in a recording material that utilizes a color-forming reaction between a colorless or light-colored leuco dye and a color developer that causes the leuco dye to develop special color on contact, the color developer is represented by the following general formula (1). A heat-sensitive recording material characterized in that it uses at least one type of phenolic compound is provided.

(In the formula, X, Y, and Z each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group,
represents an aryloxy group, an aralkyl group, or an aralkyloxy group, and furthermore, X, Y, and 2 may mutually form a ring).
) Since the phenolic compound represented by
It has excellent storage stability of colored images and has a high degree of background color development.

Specific examples of the phenolic compound represented by the general formula (1) used in the present invention are shown below, but the present invention is not limited thereto.

Compound No. Structure The leuco dye used in the present invention is generally a leuco dye known for this type of leuco recording material, such as triphenylmethane, fluoran, or phenothiazine.

Leuco compounds of dyes such as auramine and spiropyran 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 (also known as crystal violet lactone), 3.3-bis(p- dimethylaminophenyl)-6-diethylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorphthalide, 3.3-his(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlor fluorane,
3-dimethylamine-5,7-dimethylfluorane, 3
-diethylamine-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorophenyl 3-(N-p-tolyl-
N-ditylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-+N-(3'-trifluoromethylphenyl)
amino)-6-dinithylaminofluorane, 2-H,
6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(o-chloroanilino) ) fluorane.

3-dibutylamino-7-(o-chloroanilino)fluoran, 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N,N- diethylamino)-5-methyl-7-(
N,N-diethylamino)fluorane, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-virillospiran.

6'-Bromo-3'-methoxy-benzoindolino-pyrylosbilane, 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'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)
Phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3-morpholino-7-(N-propyrut) 3-pyrrolidino-7-trifluoromethylanilino)fluorane, 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-p-toluidino)-7-(α-phenyl ethylamino)fluoran, 3-diethylamino-7-(0-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-piperidinofluoran Oran, 2-
Chloro-3-(N-methyltoluidino)-7-(p-n
-butylanilino)fluorane, 3-(N-benzyl-N-cyclohexylamino)~5
．． 6-penzo 7-α-naphthylamino-4-promofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
-15--benzofluorane, 3-diethylamino-6-methyl-7-(2',4'-
Dimethylamino-fluorene etc.

3-(P-dimethylaminophenyl)-3-+],]-
His(P-dimethylaminophenyl)ethylene-2-yl)phthalide, 3-(p-dimethylaminophenyl)-311,1-bis(p-dimethylaminophenyl)ethylene-2-yl)-6-dimethylamino Phthalide, 3-(p-dimethylaminophenyl)-3-(1-p-
dimethylaminophenyl-1-phenylethylene-2-
yl) phthalide, 3-(p-dimethylaminophenyl)-3-(]-]p
-dimethylaminophenyl-1p-chlorophenylethylene-2-yl)-6-dimethylaminophthalide, 3-
(4'-dimethylamino-2'-methoxy)-3-(1
"-P-dimethylaminophenyl-1"-p-chlorophenyl-ILZ3N-butadien-4"-yl) A: nzophthalide, 3-(4'-dimethylamino-2'-benzyloxy)-3-(1"- p-dimethylaminophenyl-11-phenyl-1''.

3″-butadien-4″-yl)benzophthalide, 3-
Dimethylamino-6-dimethylamino-fluorene-9
-spiro-3'-(6'-dimethylamino)phthalide,
3. BisH-cp-dimethylaminophenyl)-2-
(p-methoxyphenyl)ethynyl l-4,5,6,7
-titrachlorophthalide, 3~His++, ]-bis(4-pyrrolidinophenyl)
ethylene-2-yl)-5,5-dichloro-4,7-dibromophthalide, bis(p-dimethylaminostyryl)-1-naphthylenesulfonylmethane, etc.

Further, in the present invention, the phenolic compound represented by the general formula (I) is used as a color developer, but if necessary, various electron-accepting compounds such as phenolic compounds, thiophenolic compounds, thiourea Derivatives, organic acids, metal salts thereof, etc. can be used in combination, and specific examples thereof include those shown below.

Bentonite, zeolite, acid clay, activated clay, silica gel, phenolic resin, 4.4'-impropylidene bisphenol, 4.4'
-inpropylidene bis(0-methylphenol), 4.4' -tcangli-butylidene bisphenol 4
．． 4'-isopropylidene bis(0-tert-butylphenol), 4.4'-cyclohexylidene diphenol, 4.4'
-isopropylidene bis(2-chlorophenol), 2.2'-methylenebis(4-methyl-6-tert-butylphenol), 2.2'-methylenebis(4-ethyl-6-tert-butylphenol), 4.4 '-Butylidene bis(6-tert-butyl-
2-methyl)phenol, 1.1.3-)lis(2-methyl-4-hydroxy-
5-tert-butylphenyl)butane, 1.1.3-tris(2-methyl-4-hydroxy-5
-cyclohexylphenyl)butane, 4.4'-thiobisC6-tert-butyl-2-methyl)phenol, 4.4'-diphenolsulfone, 4.2'-diphenolsulfone, 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, 1,7-bis(4-hydroxyphenylthio)-3,5
-dioxahebutane, 1,5-bis(4-hydroxyphenylthio)-3-oxapentane, ], 3-bis(4-hydroxyphenylthio)-propane, 2,2'-methylenebis(4-ethyl-6) -tert-butylphenol), 1.3-bis(4-hydroxyphenylthio)-2-hydroxypropane, N,N'-diphenylthiourea, N,N'-di(m-chlorophenyl)thiourea, salicylanilide, 5-chloro-salicylanilide.

salicyl-〇-chloroanilide, 2-Hydroxy-3-naphthoic acid.

Antipyrine complex of zinc thiocyanate, zinc salt of 2-acetyloxy-3-naphthoic acid, 2-hydroxy-1-
Naphthoic acid, I-hydroxy-2-naphthoic acid, zinc, aluminum of hydroxynaphthoic acid.

Metal salts such as calcium Bis-(4-hydroxyphenyl)acetic acid methyl ester, Bis-(4-hydroxyphenyl)acetic acid benzyl ester, 1.3-bis(4-hydroxycumyl)benzene, 1.
4-bis(4-hydroxycumyl)benzene, 2.4'
-diphenolsulfone, 3,3'-diallyl-4,4'-diphenolsulfone.

antipyrine complex of α, α-bis(4-hydroxyphenyl)-α-methyltoluene zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 3, dihydroxy-4′-methyldiphenylsulfone, and the like.

In order to obtain the heat-sensitive recording material of the present invention, the leuco dye, developer and auxiliary components may be supported on a support.

As the binder in this case, various conventional binders can be used as appropriate. Specific examples of such binders include the following.

Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic acid ester copolymer, acrylamide/acrylic acid ester/methacrylic acid In addition to water-soluble polymers such as terpolymer, styrene/maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, Emulsions such as polyurethane, polyacrylic acid ester, polymethacrylic acid ester, vinyl chloride/vinyl acetate copolymer, ethylene/vinyl acetate copolymer, styrene/butadiene copolymer, styrene/butadiene/acrylic copolymer, etc. Latex.

Furthermore, when obtaining a heat-sensitive recording material according to the present invention, various heat-fusible substances can be used as a heat sensitivity improver, if necessary, and specific examples thereof include the following compounds.

Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and valmitic acid amide, fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc valmitate, and zinc behenate, P-benzyl biphenyl, terphenyl,
Triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β-naphthoic acid phenyl ester, ]-hydroxy-2-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid methyl ester, diphenyl carbonate, Terephthalic acid dibenzyl ester, terephthalic acid dimethyl ester, 1
, 4-dimethoxynaphthalene, 1,4-jethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1.2
-bis(phenoxy)ethane, 1,2-bis(3-methylphenoxy)ethane, 1.2-bis(4-methylphenoxy)ethane, 1,4-bis(phenoxy)butane,
1.4-bis(phenoxy)-2-butene, 1,2-bis(4-methoxyphenylthio)ethane, dibenzoylmethane,! , 4-bis(phenylthio)butane, 1.4
-bis(phenylthione-2-butene, ], ]2-bis(4-methoxyphenylthio)ethane, 1,3-bis(
2-vinyloxyethoxy)benzene, ], 4-bis(
2-vinyloxyethoxy)benzene, P-(2-vinyloxyethoxy)biphenyl, P-aryloxybiphenyl, P-propargyloxybiphenyl, dibenzoyloxymethane, 1,3-sibenzoyloxybroban, dibenzyl disulfide, 1,1-diphenylethanol, 1.1-diphenylpropatol, p-(benzyloxy)benzyl alcohol, 1,3-diphenoxy-2-propatol, N-octadecylcarbamoyl-P-methoxycarbonylbenzene, N-octadecylcarbamoyl Benzene, oxalic acid dibenzyl ester, l.

5-bis(P-methoxyphenyloxy)-3-oxapentane and the like.

Further, in the present invention, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, lubricants, pressure coloration inhibitors, etc., can be used in combination, if necessary. In this case, the filler includes, for example, calcium carbonate,
Silica, zinc oxide, titanium oxide, aluminum hydroxide,
In addition to inorganic fine powders such as zinc hydroxide, barium sulfate, clay, talc, and surface-treated calcium and silica, urea-formalin resin, styrene/methacrylic acid copolymer,
Examples include organic fine powder such as polystyrene resin, and examples of lubricants include higher fatty acids and their metal salts, higher fatty acid amides, higher fatty acid esters, and various animal, vegetable, mineral, or petroleum waxes. can be given.

Further, regarding the layer structure, it may be multilayer or multilayer, and an over layer, an under layer, and a back layer may be provided as necessary.

〔Effect of the invention〕

The heat-sensitive recording material of the present invention using the phenolic compound represented by the general formula (1) as a color developer has excellent color density, high background whiteness, and excellent storage stability.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Examples 1-2 and Comparative Examples 1-2 The following mixtures were each ground in a magnetic ball mill for two days to prepare [Liquid A], [Liquid B], and [Liquid C].

[Liquid A] 3-(N-methyl-N-cyclohexyl)amino 2
0 parts - 10% aqueous solution of 6-methyl to 7-anilite fluoran polyvinyl alcohol 20 parts water
60 copies [B
Liquid] Phenolic compound in Table 1 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water
60
@ [Liquid C] Calcium carbonate 20 parts 5% aqueous solution of methylcellulose 20 parts water
60 parts Next, 10 parts of [Liquid A], 30 parts of [Liquid B] and 30 parts of [Liquid C] were mixed to form a thermosensitive coloring layer forming liquid, which was weighed at 50 g/
Dye adhesion amount after drying on m2 of high quality paper is 0.5g/m2
A heat-sensitive color layer was formed by applying and drying the mixture to a horse, and then the layer surface was calendered to obtain a surface smoothness of 500 to 600 seconds to prepare a heat-sensitive recording material.

The heat-sensitive recording material obtained as described above was tested at 150°C and 2 kg/c+ using a thermal gradient tester manufactured by Toyo Seiki Seisakusho.
Printed under the conditions of J1 second, and then printed under the dry condition of 60℃ for 4
It was stored for 24 hours at 0° C. and 90% humidity, and the image density and background density were measured using a Maghes densitometer RD914. The above results are shown in Table I.

As is clear from the results in Table 1, the recording material of the present invention has sufficient color density and excellent storage stability in the image area and the background area.

Patent applicant Rico Co., Ltd.

Claims (1)

[Claims] (1) In a heat-sensitive recording material that utilizes a color-forming reaction between a colorless or light-colored leuco dye and a color developer that causes the leuco dye to develop color upon contact, the color developer may be of the following general formula (
A heat-sensitive recording material characterized by using at least one type of phenolic compound represented by I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, X, Y, and Z are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, and an aralkyloxy group. (represents a group, and furthermore, X, Y, and Z may mutually form a ring)