JPS6116888A - Heat sensitive recording body - Google Patents

Abstract

PURPOSE:To improve the recording sensitiveness by containing a specific phenokydine compound in a heat sensitive recording layer. CONSTITUTION:At least one sort of compound which can be indicated by a formula is contained in a heat sensitive recording layer of a heat resistive recording body utilized a coloration reaction between a colorless or light color basic dye and a coloration drug colorable with a contact of a dye. In the formulae, R1 and R2 indicate the hydrogen atom or alkyl group of C1-C4, Y1 and Y2 indicate the hydrogen atom, the chlorine atom, acetyl group, propinyl group, methoxyl group, methylthio group, methoxycarbonyl group, cyano group, nitro group, or cyclohexinylsel group, and (n) indicates 2 or 4. However, Y1 and Y2 can not be the hydrogen atom at the same time. The using ratio of the basic dye and the coloration drug is 100wt.pts of the dye to 100-700wt.pts. of coloration drug, and preferably approximately 150-400wt.pts. are used. Thereby, an extremely favorable recording sensitiveness improvement effect can be obtained without a deterioration of a degree of a white coloration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive recording medium, and particularly to a heat-sensitive recording medium that has high whiteness and excellent high-speed recording suitability.

Conventionally, heat-sensitive recording materials are well known in which a coloring reaction between a colorless or light-colored basic dye and a coloring agent is used to bring a recoloring substance into contact with heat to obtain a colored image. In recent years, with the improvement of thermal recording apparatuses such as thermal printers using such thermal recording bodies, the speed in the thermal recording layer has been significantly increased. As the speed of such equipment and hardware increases, the heat-sensitive recording media used are naturally required to greatly improve the recording sensitivity, and many proposals have been made in this regard. However, as the recording sensitivity improves, new drawbacks such as a decrease in the whiteness of the recording layer are accompanied, so that satisfactory results are not necessarily obtained. In view of the current situation, the present inventors have conducted various studies with the aim of improving the recording sensitivity of a heat-sensitive recording medium without reducing whiteness.

In particular, many proposals have been made to improve recording sensitivity by using a thermofusible substance in combination with a basic dye and a coloring agent, but the scope of investigation of this thermofusible substance has been greatly expanded. As a result of extensive research, we have found that when a compound represented by the following general formula (1) is used as a thermofusible substance, stearic acid amide, palmitic acid amide, etc., which have been proposed as a thermofusible substance, can be produced. The present inventors have discovered that an extremely good recording sensitivity improvement effect can be obtained without causing a decrease in whiteness compared to fatty acid amides, etc., and have achieved the present invention.

The present invention provides a heat-sensitive recording material that utilizes a coloring reaction between a colorless or light-colored basic dye and a coloring agent that can develop color when it comes into contact with the dye. This is a heat-sensitive recording material characterized by containing at least one of the compounds shown below.

The alkyl group, Yl and Yl represent a hydrogen atom, a chlorine atom, an acetyl group, a propionyl group, a methoxy group, a methylthio group, a methoxycarbonyl group, a cyano group, a nitro group, or a cyclohexenyl group, and n represents 2 or 4. . however,
Both Yl and Yl are never hydrogen atoms. ) It is not clear why certain thermofusible substances such as those mentioned above exhibit the effect of improving recording sensitivity without reducing whiteness, but the chemical structure is similar to that of basic dyes or organic coloring agents. One factor is considered to be that the compatibility of the entire mixed system is increased as a result.

Specific examples of such thermofusible substances include 1-(2-chlorophenoxy)-2-phenoxyethane (+++, p, 81°C), 1-(2-chlorophenoxy)-2-(2 -methylphenoxy)ethane (m, p, 8
7°C), 1-(2-chlorophenoxy)-2-(3-methylphenoxy)ethane (n+, p, 85°C), 1-(
2-Chlorphenoxy)-2-(4-methylphenoxy)ethane (song, 9.89°C), 1-(4-chlorophenoxy)-2-phenoxyethane (m, p, 100°C)
, 1-(4-chlorophenoxy)-2-(2-methylphenoxy)ethane (s+, p, 81.s°C), 1-
(4-Chlorphenoxy)-2-(3-methylphenoxy)ethane (m, p.

79.5°C), 1-(4-chlorophenoxy)-2-(
4-methylphenoxy)ethane (m, p, 'l 32'
C), 1-(4-acetylphenoxy)-2-phenoxyethane (m, p, 139°C), 1-(4-acetylphenoxy)-2-(2-methylphenoxy)ethane (m
, p, 1) 9.5°C), 1-(4-propionylphenoxy)-2-phenoxyethane (9.120°C)
, 1-(2-methoxyphenoxy)-2-(4-methylphenoxy)ethane (i+', p.

89°C), 1-(3-methoxyphenoxy)-2-(4
-methylphenoxy)ethane (m, p, 75°C), 1.
2-di(4-methoxyphenoxy)ethane (m, p,
128℃), 1-(4-methoxyphenolic)-2-
Phenoxyethane (m, p', 103°C), 1-(4
-methoxyphenoxy) -2-(2-methylphenoxy)ethane (+s, p, 80°C), 1-(4-methoxyphenoxy)-2-(3-methylphenoxy)ethane (m, p, 1) 2°C ), 1-(4-methoxyphenoxy)-2-(4-methylphenoxy)ethane (m, p,
129°C), 1-(4-methylthiophenoxy)-2
-phenoxyethane (m, p, 1) 2℃), 1-(4-
methoxycarbonylphenoxy)-2-phenoxyethane (n+, p, 106°C), 1-(4-cyanophenoxy)-2-phenoxyethane (m, p, 1) 0°C), 1
-(4-cyanophenoxy)-2-(2-methylphenoxy)ethane (m, p', 98°C), 1-(4-cyanophenoxy)-2-(3-methylphenoxy)ethane (
■, p, 96.5℃), 1-(4-cyanophenoxy)
-2-(4-methylphenoxy)ethane (m.

p, 1) 1.5°C), 1-(4-nitrophenoxy)-
2-phenoxyethane (m, p, 87°C), 1-(4-
Nitrophenoxy)-2-(4-methylphenoxy)ethane (+, p, 103°C), 1-(4-cyclohexenylphenoxy)-2-phenoxyethane (m, p, 1)
6°C), 1-(4-chlorophenoxy)-2-(4-t
-butylphenoxy)ethane (m, p, 1) 1°C), 1
-(4-methoxyphenoxy)-2-(4-t-butylphenoxy)ethane (m, p, 109.5°C), 1-
(4-acetylphenoxy)-2-(4-t-butylphenoxy)ethane (+n, p, 101.5°C), 1-
(4-methylthiophenoxy)-2-(4-t-butylphenoxy)ethane (m, p, 98°C), 1-(4-cetylphenoxy)-4-phenoxybutane (m, p,
106°C), 1-(4-methoxyphenoxy)-4-phenoxybutane (n+, p, 100°C), 1-(4-methylthiophenoxy)-4-phenoxybutane (m.

9.109°C), or 1-(4-cyanophenoxy)-
Examples include 4-phenoxybutane (m, p, 72°C).

These thermofusible substances are generally synthesized by Williamson's ether synthesis method, but two or more of them may be used in combination, and as long as the desired effect of the present invention is not inhibited, for example, stearamide, Fatty acid amide such as stearic acid methylene bisamide, oleic acid amide, palmitic acid amide, coconut fatty acid amide, 2.2'-methylenebis(4-methyl-6-t-butylphenol), 4.4
Hindered phenols such as '-butylidenebis(6-t-butyl-3-methylphenol), 1.1',3-)lis(2-methyl-4-hydroxy-5-t-butylphenol)butane, 2-( Ultraviolet absorbers such as 2'-hydroxy-5'-methylphenyl)-benzotriazole and 2-hydroxy-4-benzyloxybenzophenone, and various known thermofusible substances can also be used in combination.

The amount of the thermofusible substance having the above-mentioned specific structure used is not necessarily limited, but is generally 10 to 1000 parts by weight, preferably 50 to 500 parts by weight, per 100 parts by weight of the coloring agent. It is desirable to adjust within a range of degrees.

In the heat-sensitive recording material of the present invention, examples of the colorless or light-colored basic dye constituting the recording layer include the following.

3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide, 3.3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl")-3-(1, 2-dimethylindole-3-
yl)phthalide, 3-(p-dimethylaminophenyl)
-3-(2-methylindol-3-yl)phthalide,
3.3-bis(1,2-dimethylindol-3-yl)-5-dimethylaminophthalide, 3.3-bis(1°2-dimethylindol-3-yl)-6-dimethylaminophthalide, 3.3-bis(9-ethylcarbazol-3-yl)-6-dimethylaminophthalide, 3.3-
Triallyl such as bis(2-phenylindol-3-yl)-6-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-(1-methylpyrrol-3-yl)-6-dimethylaminophthalide, etc. Methane dye, 4.4
'-Bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl-leucoolamine, N72.
4.5-) Diphenylmethane dyes such as dichlorophenylleucoolamine, thiazine dyes such as benzoylleucomethylene blue and p-nitrobenzoylleucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3
Spiro dyes such as -ethyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho(6'-methoxybenzo)spiropyran, 3-propyl-spiro-dibenzobilane , Rhodamine-B-anilinolactam, Rhodamine(p=,ni)roanilino)lactam, Rhodamine(0-chloroanilino)lactam and other lactam dyes, 3-dimethylamino-7-medoxyfluorane, 3-diethylamino-6 -Medoxyfluorane, 3-diethylamino-7-medoxyfluorane, 3-
Diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3-(N-
Ethyl-p-)luidino)-7-methylfluorane, 3
-diethylamino-7-N-acetyl-N-methylaminofluorane, 3-ethylamino? -N-methylaminofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-N-methyl-N-benzylaminofluorane, 3-diethylamino-7-N-chloroethyl-N-methyl Aminofluorane, 3-diethylamino-7-N-diethylaminofluorane, 3-(N-ethyl-p-)luidino)-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-p-) Luidino〉-6-methyl-7-(p-)luidino)fluoran, 3-diethylamino-6-methyl-
7-phenylaminofluorane, 3-dibutylamino-
6-Methyl-7-phenylaminofluorane, 3-diethylamino-7-(2-carbomethoxy-phenylamino)fluorane, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-phenyl Aminofluorane, 3-pyrrolidino-6-methyl-7-phenylaminofluorane, 3-piperidino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl7-xylidinofluorane, 3 -diethylamino-7
-(o-chlorophenylamino)fluoran, 3-dibutylamino-7-(o-chlorophenylamino)fluoran, 3-pyrrolidino-6-methyl-7-p-butylphenylaminofluoran, 3-(N-methyl-N -n-
amyl)amino-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-Nn-amyl)amino-
6-Methyl-7-phenylaminofluorane, 3-(N
-ethyl-N-iso-amyl)amino-6-methyl-
7-phenylaminofluorane, 3-(N-methyl-N
-n-hexyl)amino-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-Nn-hexyl)amino-6-methyl-7-phenylaminofluorane, 3-(N-ethyl -N-β-ethylhexyl)amino-6-methyl-7-phenylaminofluoran and the like.

In the present invention, the coloring agent used in combination with the above-mentioned basic dye is not particularly limited.
Various coloring agents are used that have the property of liquefying, vaporizing, or melting when the temperature rises, and that have the property of causing coloration when they come into contact with the above-mentioned basic dye. Typical specific examples include 4-tert-butylphenol, α-naphthol,
β-naphthol, 4-acetylphenol, 4-te
rt-octylphenol, 4.4'-5ee-butylidene diphenol, 4-phenylphenol, 4.4'
-dihydroxy-diphenylmethane, 4.4'-isopropylidenediphenol, hydroquinone, 4.4'-
Cyclohexylidene diphenol, 4゜4'-dihydroxydiphenyl sulfide, 4゜4'-thiobis(6
-tert-butyl-3-methylphenol), 4.4
'-dihydroxydiphenylsulfone, hydroquinodimonobenzyl ether, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,4.4'
-trihydroxybenzophenone, 2.2', 4.4'
monotetrahydroxybenzophenone, dimethyl 4-hydroxyphthalate, methyl 4-hydroxybenzoate, 4-
Ethyl hydroxybenzoate, propyl 4-hydroxybenzoate, 5ec-butyl 4-hydroxybenzoate, 4
-pentyl hydroxybenzoate, phenyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, tolyl 4-hydroxybenzoate, chlorophenyl 4-hydroxybenzoate, phenylpropyl 4-hydroxybenzoate, phenethyl 4-hydroxybenzoate, 4 -Phenolic compounds such as p-chlorobenzyl hydroxybenzoate, p-methoxybenzyl 4-hydroxybenzoate, novolac type phenolic resin, phenol polymer, benzoic acid, 1) tert-butylbenzoic acid, trichlorobenzoic acid, Terephthalic acid, 3-see-butyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3.5-dimethyl-4-hydroxybenzoic acid, salicylic acid, 3-isopropylsalicylic acid, 3
tert-butylsalicylic acid, 3-benzylsalicylic acid, 3-(α-methylbenzyl)salicylic acid, 3-chloro-5-(α-methylbenzyl)salicylic acid, 3.5-di-tart-butylsalicylic acid, 3-phenyl-5- (
α,α-dimethylbenzyl)salicylic acid, 3,5-di-
Aromatic carboxylic acids such as α-methylbenzyl salicylic acid, and their phenolic compounds; Examples include acidic substances.

The ratio of the basic dye to the coloring agent is generally 100 to 700 parts by weight, preferably 150 to 400 parts by weight, per 100 parts by weight of the dye. Incidentally, it is of course possible to use two or more kinds of the basic dye and the coloring agent in combination as necessary.

Coating liquids containing these materials are generally prepared by using water as a dispersion medium and dispersing dyes and coloring agents together or separately using a ball mill, attritor, sand grinder, or other stirring or pulverizing machine. Ru.

Such coating liquids usually contain starches and binders as binders.
Hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, gum arabic, polyvinyl alcohol, styrene/maleic anhydride copolymer salt, styrene/butadiene copolymer emulsion, etc. account for 2 to 40% by weight of the total solids, preferably 5%. ~25% by weight is used. Furthermore, various auxiliary agents can be added to the coating liquid as necessary. Examples include dispersants such as sodium dioctyl sulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, and fatty acid metal salts, other antifoaming agents, fluorescent dyes, and coloring dyes.

In addition, in order to improve the adhesion of residue to the recording head and further whiten the heat-sensitive recording layer, kaolin, clay, talc, etc.
Inorganic pigments such as calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine particulate anhydrous silica, and activated clay can also be added. In addition, stearic acid, polyethylene,
A dispersion of carnauba wax, paraffin wax, calcium stearate, zinc stearate, ester wax, etc. or a wax such as Elsion may be added to prevent the recording layer from sticking when it comes into contact with the recording head.

In the heat-sensitive recording material of the present invention, the method for forming the recording layer is not particularly limited, and can be formed according to conventionally well-known and commonly used techniques. A suitable coating device such as a coater or a blade coater is used.

Further, the amount of the coating liquid to be applied is not particularly limited, and is generally adjusted to a dry weight of 2 to 12 g/nf, preferably 3 to 10 g/rd.

Note that the support is not particularly limited, and paper, synthetic fiber paper, synthetic resin film, etc. can be used as appropriate, but paper is generally preferably used.

Furthermore, it is possible to provide an overcoat layer on the recording layer for purposes such as protecting the recording layer, and it is of course also possible to provide an undercoat layer on the support. This can be added using known techniques.

Thus, the heat-sensitive recording material obtained according to the present invention has excellent suitability for high-speed recording, high whiteness, and extremely well-balanced properties in terms of quality.

The present invention will be described in more detail with reference to Examples below, but it is of course not limited thereto.

Further, unless otherwise specified, parts and percentages in the examples indicate parts by weight and percentages by weight, respectively.

Example 1 ■ Preparation of liquid A 3-(N-cyclohexyl-N-methylamino)-6-
Methyl-7-phenylaminofluorane
10 parts 1-(4-methoxyphenoxy)-
2-phenoxyethane sheath, py1oa℃ 20
1 part methyl cellulose 5% aqueous solution 15 parts water
120 parts of this composition was ground to an average particle size of 3 μm using a sand grinder.

■ Preparation of B solution 4,4'-isopropylidene diphenol 30 parts Methyl cellulose 5% aqueous solution 30 parts water
70 parts of this composition was ground to an average particle size of 3 μm using a sand grinder.

■ Formation of recording layer 165 parts of liquid A, 130 parts of liquid B, 30 parts of silicon oxide pigment, 2
150 parts of 0% oxidized starch aqueous solution and 55 parts of water were mixed and stirred to prepare a coating liquid. The obtained coating liquid was coated and dried on a base paper of 50 g/rrr so that the coated amount after drying was 7.5 g/+yl to obtain a heat-sensitive recording paper.

Example 2 In preparing liquid A, 1-(4-methoxyenoxy)-2-
1-(4-chlorophenoxy)-2-phenoxyethane (m, p) instead of phenoxyethane.

A thermosensitive recording paper was obtained in the same manner as in Example 1, except that the temperature was 100°C.

Example 3 In preparing liquid A, 1-(4-methoxyenoxy)-2-
1-(4-cyanophenoxy)-2-(2-methylphenoxy)ethane (+n, p,
A thermosensitive recording paper was obtained in the same manner as in Example 1, except that the temperature was 98°C.

Comparative Example 1 In preparing liquid A, 1-(4-methoxyphenoxy)-2
- A thermosensitive recording paper was obtained in the same manner as in Example 1 except that stearamide was used instead of phenoxyethane.

Comparative Example 2 In preparing liquid A, 1-(4-methoxyphenoxy)-2
- Thermal sensitivity was carried out in exactly the same manner as in Example 1, except that stearamide was used instead of phenoxyethane, and benzyl p-hydroxybenzoate was used instead of 4,4'-isopropylidene diphenol in the preparation of liquid B. I got the recording paper.

The five types of heat-sensitive recording paper thus obtained were subjected to a comparative test of recording sensitivity and whiteness of the recording layer, and the results are shown in the table. The recording sensitivity is determined by measuring the color density of a recorded image recorded using a G'■ type practical high-speed thermal facsimile (Hitachi HI FAX-700 model) using a Macbeth density needle (Macbeth RD-100R model). did. The brightness was measured using a Hunter whiteness needle.

Claims (1)

[Claims] (1) In a heat-sensitive recording material that utilizes a color reaction between a colorless or light-colored basic dye and a coloring agent that can develop color when in contact with the dye, the following general formula [I] is contained in the heat-sensitive recording layer. 1. A heat-sensitive recording material containing at least one of the compounds represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼〔I〕 (In the formula, R_1 and R_2 are hydrogen atoms or C_1 to C_
4 alkyl group, Y_1 and Y_2 are hydrogen atom, chlorine atom, acetyl group, propionyl group, methoxy group, methylthio group, methoxycarbonyl group, cyano group, nitro group,
or represents a cyclohexenyl group, and n represents 2 or 4. However, both Y_1 and Y_2 are not hydrogen atoms. )