JPH05270128A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance properties such as coloring sensitivity, high-speed recordability and texture whiteness by adding a benzylsulfide compound expressed by specific formula to a thermal recording material which uses a coloring reaction between leuco dye and a color developer. CONSTITUTION:0.5 to 10.0 pts.wt., preferably 1 to 5 pts.wt. of a benzylsulfide compound expressed by formula I for 1 pt.wt. of leuco dye, are added to a thermal recording material. In the formula, R1 is hydrogen atom, halogen atom, C1 to C4 alkyl group, alkoxy group or alkenyl group; R2 is -(CH2)-n, -(CH2)-nX (CH2)-n; X is -S-, -O-, a phenylene group; n is an integer of 1 to 10. In addition, the benzylsulfide compound can contain not only a thermal coloring layer but also an overcoat layer or an under layer. Further, a leuco dye used is of triphenylmethane, and a color developer used is a phenol compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to improvement of a heat-sensitive recording material in which a heat-sensitive color forming layer which develops color by heat is provided on a support.

[0002]

2. Description of the Related Art Various recording materials have been proposed which utilize a color-forming reaction between a colorless or light-colored leuco dye and a color-developing agent which develops color upon contact with heat and pressure. One of the heat-sensitive recording materials is advantageous in that it does not require complicated processing such as development and fixing, can be recorded in a short time with a relatively simple device, generates little noise, and has a low cost. It is useful as various recording materials such as electronic calculators, facsimiles, ticket vending machines, label printers and recorders.

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 thermal recording material using the leuco dye and the color developer is widely used because of its high image density and high whiteness of the background.

As a high-sensitivity developer, p-hydroxybenzoic acid ester is disclosed in, for example, JP-A-56-144193 and JP-A-59-2 in order to cope with high-speed recording.
Although hydroxynaphthoic acid esters have been proposed in Japanese Patent No. 2793, etc., the heat-sensitive recording materials using these compounds as color developers have a drawback that storage stability of image areas is poor. Further, JP-A-59-165680 proposes to use a thioester compound as a developer, but a heat-sensitive recording material using the compound has a high fastness to oils and fats in the image area but is high. It is hard to say sensitivity.
In addition, various proposals have been made for increasing the sensitivity by adding various heat-fusible substances.
-57989, JP-A-58-87088,
A phenyl ether derivative is proposed in JP-A-61-31287, a naphthol derivative is disclosed in JP-A-58-87064, and a benzylbiphenyl is proposed in JP-A-60-82382.

[0005]

However, the heat-sensitive recording materials using these color developers or heat-fusible substances have the following problems in terms of color development sensitivity, background whiteness, storability (image fading, white powder generation, etc.). But it's still not enough. The object of the present invention is excellent in color development sensitivity and suitable for high-speed recording materials,
Moreover, it is to provide a heat-sensitive recording material having a high degree of background whiteness.

[0006]

According to the present invention, a heat-sensitive recording material utilizing a color-forming reaction between a colorless or light-colored leuco dye and a color developer that develops the color when the leuco dye is brought into contact with (I) A heat-sensitive recording material containing a benzyl sulfide compound represented by the formula (1).

[Chemical 1]

Since the heat-sensitive recording material of the present invention contains the benzyl sulfide compound represented by the above general formula (I), it has excellent coloring sensitivity, is suitable for high-speed recording materials, and has a high degree of background coloring. Become.

The benzyl sulfide compound represented by the general formula (I) used in the present invention may be contained not only in the thermosensitive color developing layer but also in any of the overcoat layer and the underlayer. When it is contained in the thermosensitive coloring layer, the amount thereof used is 0.5 to 10.0 parts by weight, preferably 1 to 5 parts by weight, based on 1 part by weight of the leuco dye. Specific examples of the benzyl sulfide compound represented by the general formula (I) used in the present invention are shown below, but the present invention is not limited thereto.

[Table 1]

In the present invention, the leuco dyes used in the thermosensitive coloring layer may be used alone or in admixture of two or more.
As such leuco dyes, those applied to this type of heat-sensitive material are arbitrarily applied, for example, triphenylmethane-based, fluorane-based, phenothiazine-based, auramine-based, spiropyran-based, indolinophtalide-based, etc. Leuco compounds of dyes 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-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-isobutyl-6-
Methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3- (Np-tolyl-N-ethylamino) -6-
Methyl-7-anilinofluorane, 3-pyrrolidino-6-
Methyl-7-anilinofluorane, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluorane, 2- {3,6-bis (diethylamino) -9- (o-
Chloranilino) xanthylbenzoic acid lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino-7- (o-chloranilino) fluorane, 3-dibutylamino-7- (o -Chloranilino) fluorane, 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-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino ) Fluoran, 3- (N, N-diethylamino) -5
-Methyl-7- (N, N-dibenzylamino) fluorane, benzoyl leuco methylene blue, 6'-chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-
3'-methoxy-benzoindolino-spiropyran, 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-propyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethyl) Anilino) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl)
Methylaminofluorane, 3-diethylamino-5-chloro-
7- (α-phenylethylamino) fluorane, 3- (N-ethyl
-p-Toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7-
(α-Phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3- (N-methyltoluidino) -7- (pn-butylanilino) fluorane, 3-
(N-methyl-N-isopropylamino) -6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3,6-bis (dimethylamino) fluorene spiro ( 9,3 ')-6'-Dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino) -5,6-benzo-7-α
-Naphthylamino-4'-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N
-(2-Ethoxypropyl) amino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-tetrahydrofurfurylamino-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.

Further, as the color developer used in the thermosensitive color developing layer of the present invention, various electron-accepting compounds which develop the above leuco dye upon contact, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic compounds Acids and metal salts thereof are preferably applied, and specific examples thereof include those shown below.

4,4'-isopropylidene bisphenol,
4,4'-isopropylidene bis (o-methylphenol),
4,4'-secondary butylidene bisphenol 4,4'-isopropylidene bis (2-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'-butylidenebis
(6-tert-butyl-2-methylphenol), 1,1,3
-Tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis ( 6-tert-butyl-2-methylphenol),
4,4'-diphenol sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone, 4-benzyloxy-4'-hydroxydiphenyl sulfone, 4,4'-diphenol sulfoxide, P-hydroxy isopropyl benzoate, P -Benzyl hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,
5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane, 1,3-bis (4-hydroxyphenylthio) -propane, 1,3-bis (4-hydroxyphenylthio) ) -2-Hydroxypropane, N, N'-diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, 2-hydroxy-3-naphthoic acid, 2 -Hydroxy-1
-Naphthoic acid, 1-hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum and 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'-diphenol sulfone, 3,3'-diallyl-4,4'-diphenol sulfone, 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) etc.

In order to produce the heat-sensitive recording material of the present invention,
When the leuco dye and the color developer are bound and supported on a support, various conventional binders can be appropriately used, and specific examples thereof include the following.

Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose and ethyl cellulose, polyacrylic acid sodium -Da, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene /
Maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, soda alginate, gelatin, other water-soluble polymers such as casein, polyvinyl acetate, polyurethane, polyacrylic acid, Polyacrylic acid ester, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene /
Emulsion such as vinyl acetate copolymer, latex such as styrene / butadiene copolymer and styrene / butadiene / acrylic copolymer.

Further, in the present invention, the above-mentioned benzyl sulfide compound is used as the sensitivity improving agent, but if necessary, various other heat-fusible substances can be used in combination. Include, but are not limited to: stearic acid,
Fatty acids such as behenic acid, stearic acid amide, fatty acid amides such as palmitic acid amide, zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, fatty acid metal salts such as zinc behenate, p-
Benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, phenyl β-naphthoate, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, Diphenyl carbonate, glare coal carbonate, dibencil terephthalate, dimethyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-diphenoxyethane, 1, 2-bis (3-methylphenoxy) ethane, 1,2-
Bis (4-methylphenoxy) ethane, 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) bifer, p-aryloxypphenyl, p-propargyloxybiphenyl, 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.

In the case of obtaining a heat-sensitive recording material according to the present invention, a leuco dye, a color developer, the compound of the present invention and, if necessary, additional components commonly used in this kind of heat-sensitive recording material such as a filler and a surface active agent. Agents and 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,
In addition to barium sulfate, clay, kaolin, talc, inorganic fine powder such as surface-treated calcium and silica, urea-
Examples thereof include organic fine powders such as formalin resin, styrene-methacrylic acid copolymer, polystyrene resin, and vinylidene chloride resin.

Regarding the layer structure, it may be a single layer or a multilayer, and an over layer, an under layer and a back layer may be provided if necessary.

[0018]

Next, the present invention will be described in more detail with reference to Examples. In addition, all the following parts and% are based on weight.

Example 1 The following mixture was ground in a magnetic ball mill for 2 days to prepare [Liquid A], [Liquid B], [Liquid C], and [Liquid D]. [Solution A] 3- (N-methyl-N-cyclohexyl) amino-6-methyl 20 parts -7-anilinofluorane 10% aqueous solution of polyvinyl alcohol 20 parts Water 60 parts [Solution B] 4,4'-isopropyi Redene diphenol 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts [C liquid] Specific example No. Compound of 1 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts [D liquid] calcium carbonate 20 parts methyl cellulose 20 parts water 60 parts [A liquid] 10 parts, [B liquid] 30 parts, [C liquid] 20
Part, [D liquid] 40 parts, and 10 parts of zinc stearate dispersion liquid (trade name HZ730 concentration 30%) manufactured by Chukyo Yushi Co., Ltd. are used as a thermosensitive color forming layer forming liquid, which has a basis weight of 50 g / m ^2.
After coating and drying on high quality paper so that the amount of dye adhering after drying will be 0.5 g / m ² , a thermosensitive coloring layer is provided, and then the layer surface is calendered so that the surface smoothness becomes 500 to 600 seconds. It was applied to prepare a heat-sensitive recording material.

Example 2 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 C] in Example 1. [Liquid E] Specific example No. Compound of 2 20 parts Water 60 parts 10% aqueous solution of polyvinyl alcohol 20 parts

Example 3 A thermosensitive recording material was prepared in the same manner as in Example 1 except that the following [F solution] was used instead of the [B solution] in Example 1. [F liquid] 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane 20 parts Water 60 parts 10% aqueous solution of polyvinyl alcohol 20 parts

Comparative Example 1 A thermosensitive recording material was prepared in the same manner as in Example 1 except that the following [G liquid] was used instead of the [C liquid] in Example 1. [Solution G] P-benzylbiphenyl 20 parts Water 60 parts 10% aqueous solution of polyvinyl alcohol 20 parts

Comparative Example 2 A thermosensitive recording material was prepared in the same manner as in Example 1 except that the following [solution H] was used in place of [solution C] in Example 1. [Liquid H] Stearamide 20 parts Water 60 parts Polyvinyl alcohol 10% aqueous solution 20 parts

The heat-sensitive recording material prepared as described above is
Printing was performed with a thermal paper coloring tester manufactured by Okura Electric Co., Ltd., and the coloring density was measured with a Macbeth densitometer RD-914. The above results are shown in Table 2.

[Table 2] As is clear from the above results, the recording material using the benzyl sulfide compound of the present invention is excellent in color developing sensitivity and color density and has high background whiteness.

[0025]

Since the heat-sensitive recording material of the present invention contains the benzyl sulfide compound represented by the above general formula (I), it has high sensitivity, excellent high-speed recording characteristics, high background whiteness, and is extremely practical. It has high quality.

Claims (1)

[Claims] 1. A heat-sensitive recording material utilizing a color-forming reaction between a colorless or light-colored leuco dye and a color-developing agent which develops a color when the leuco dye is brought into contact with a thermosensitive recording material having the following general formula (I):
A heat-sensitive recording material containing a benzyl sulfide compound represented by Chemical formula 1. [Chemical 1]