JPH0717106B2 - Thermal recording material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material excellent in color development.

[Prior art]

A general heat-sensitive recording material is a colorless or light-colored coloring dye such as leuco dye as a coloring agent on a support such as paper or film, and a phenolic compound (particularly bisphenol A) as a developer for coloring the coloring when heated. , A color-forming system composed of an acidic substance such as an organic acid, and further provided with a thermosensitive color-developing layer in which a binder, a filler, a sensitivity improver, a lubricant, and other auxiliary agents are dispersed, for example, Japanese Patent Publication No. 43-4160. Japanese Patent Publication No.45-14039,
It was introduced in Japanese Patent Laid-Open No. 48-27736 and is widely put to practical use. This type of heat-sensitive recording sheet obtains a color image by a momentary chemical reaction between a color-developing agent and a color-developing agent during heating (a thermal printer or a Facsimile having a built-in thermal head is used for heating). Therefore, compared to other recording materials, recording can be obtained in a short time with a relatively simple device without performing complicated processing such as development and fixing, there is little noise and environmental pollution, and cost is low. Due to its advantages such as low cost, it is useful for copying books, documents and the like, and is also useful as a recording material for various information and measuring instruments such as electronic calculators, facsimiles, telex and medical measuring instruments.

On the other hand, in recent years, along with the development of society, there has been an increasing demand for high speed recording and high density recording. For this reason, it is strongly desired to develop a recording material capable of coping with the speedup of the recording apparatus itself. The first method is to lower the melting point of the electron-accepting compound as a color developer to a practically acceptable level such as storage stability (for example, 80 to 120 ° C.), and set the melting start temperature with the leuco dye. It is to lower the speed and increase the speed. However, it is difficult to control the melting point of phenolic compounds such as 4,4′-isopropylidenediphenol and hydroxybenzoic acid benzyl ester, which are color-developing agents widely used in the field of thermal recording materials, and However, the phenolic compound itself is expensive and poor in practicality, and the sensitivity, image stability and whiteness of the background are not satisfactory. The second method is, for example, JP-A-53-39139 and JP-A-53-39139.
-26139, JP-A-53-5636, JP-A-53-11036, etc., various waxes, fatty acid amides, alkylated biphenyls, substituted biphenyl alkanes, coumarins are used in the thermosensitive color developing layer. Or a method of adding a low-melting-point heat-melting substance such as diphenylamines as a sensitizer (or melting point depressant) or JP-A-48-192131
53-48751, JP-A-56-62189, JP-A-58-112788
And JP-A-60-110486, there is a method of using a sensitivity improver. However, it is hard to say that the heat-sensitive recording materials produced by these methods are still sufficient in terms of color density, color sensitivity, background whiteness and the like.

〔Purpose〕

An object of the present invention is to provide a thermosensitive recording material having sufficient color density and color sensitivity, excellent long-term storage stability of recorded images, suitable for high-speed recording, high background whiteness, and extremely high practicality. is there.

〔Constitution〕

According to the present invention, in a thermosensitive recording material provided with a thermosensitive coloring layer containing a colorless or light-colored electron-donating dye and a developer, at least a compound represented by the following general formula (I) is used as the developer. There is provided a heat-sensitive recording material characterized by using one kind.

General formula (In the formula, R represents a hydrogen atom or a halogen atom) In the present invention, since the N, N'-diarylsulfamide-based compound represented by the general formula (I) is used as a developer, a high concentration is obtained. It is possible to obtain a heat-sensitive recording material which gives a colored image of 1.

Examples of specific compounds of the N, N'-diaryl sulfamides represented by the general formula (I) include those shown below.

In the present invention, these compounds may be used alone or in combination with conventional developers such as organic acids and phenols described below. The amount used is 1 to 10 parts by weight, preferably 2 to 6 parts by weight, based on 1 part by weight of the electron-donating dye. In addition, these compounds can usually be easily synthesized by reacting sulfuryl chloride on an aniline derivative at low temperature.

The colorless or light-colored electron-donating dyes used in the present invention are applied singly or as a mixture of two or more kinds, and as such dyes, those applied to this type of heat-sensitive material are arbitrarily applied, For example, leuco compounds of dyes such as triphenylmethane type, fluorane type, phenothiazine type, auramine type, spiropyran type and indolinophtalide type 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 red 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-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- -Anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluorane, 2- {3,6 -Bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoic acid lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) Fluorane, 3-dibutylamino-7- (o-chloroanilino) fluorane, 3-N-methyl-N-isoamylamino-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
-Dibenzylamino) fluorane, benzoyl leuco methylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrrolispirane, 6'-bromo-3'-methoxy-benzoindolino-pyrrolispirane, 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-trifluoromethylanilino) 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-piperidi Fluoran, 2-chloro-3-(N-Mechirutoruijino)-7-(p
-N-butylanilino) fluorane, 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 and the like.

In the present invention, as the color developer that can be used in combination with the color developer, various electron-accepting compounds such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof are preferable. It is applied and the specific example is 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 4,4'-cyclohexylidene diphenol, 4,4'-isopropylidene bis (2-chlorophenol), 2,2'-methylene bis (4-methyl-6-tert-butylphenol), 2,2'-methylene bis (4 -Ethyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-2methyl)
Phenol, 4,4'-thiobis (6-tertbutyl-2-methyl) phenol, 4,4'-diphenol sulfone, 4,4'-diphenol fluphoxide, isopropyl P-hydroxybenzoate, P-hydroxy Benzyl benzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-hydroxy) Phenylthio) -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, salicyl-o-chloroanilide 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.

In the present invention, in order to bond and support the electron-donating dye, the color developer and the auxiliary component on the support, various conventional binders can be appropriately used. For example, polyvinyl alcohol, starch and derivatives thereof. , Cellulose derivatives such as methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid ternary copolymer Polymers, styrene / maleic anhydride copolymer alkali salts, isobutylene / maleic anhydride copolymer alkali salts, water-soluble polymers such as polyacrylamide, sodium alginate, gelatin, casein, polyvinyl acetate, polyuree Styrene, styrene / butadiene copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene / vinyl acetate copolymer, styrene / butadiene / acrylic copolymer, etc. Latex can be used.

Further, in the present invention, together with the electron-donating dye, the color developer and the auxiliary component, if necessary, further auxiliary components commonly used in this type of heat-sensitive recording material, for example, a filler, a surfactant, and a thermal agent. A fusible substance (or a lubricant) 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, talc,
Inorganic fine powders such as surface-treated calcium and silica, as well as organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, and polystyrene resin can be mentioned. Are, for example, higher fatty acids or esters, amides or metal salts thereof, various waxes, condensates of aromatic carboxylic acids and amines, phenyl benzoate, higher fatty acid glycols, 3,4
-Epoxy-dialkyl hexahydrophthalate, higher ketones, and other heat-fusible organic compounds having a melting point of about 50 to 200 ° C.

The heat-sensitive recording material of the present invention can have various structures, and all of the conventionally known structures utilizing the color-forming reaction between the electron-donating dye and the color developer are included.
For example, the heat-sensitive recording material of the present invention comprises a heat-sensitive recording material having a structure in which an electron-donating dye and a developer are supported on the support as the same coating layer or separate coating layers, or an electron-donating dye. It can be used as a heat transfer type heat-sensitive recording material comprising a transfer sheet formed by supporting a support as a transfer layer and a receiving sheet formed by supporting a developer as a receiving layer. In the case of a heat transfer type heat-sensitive recording material, a desired color image can be formed on the receiving layer surface of the receiving sheet by superposing the transfer sheet so as to be in contact with the transfer layer and thermally printing from the front surface or the back surface of the polymerization sheet. .

The heat-sensitive recording material of the present invention is produced, for example, by applying a heat-sensitive layer-forming coating liquid containing each of the above-mentioned components onto a suitable support such as paper, synthetic paper, or a plastic film, and drying it. It is used as a heat-sensitive recording material for the high-speed recording which requires high image stability.

The heat-sensitive recording material of the present invention is used in various fields, and in particular, it is used for the excellent color image stability described above,
It can be advantageously used as a heat-sensitive recording type label sheet or a heat-sensitive recording type magnetic ticket paper. In the case of a heat-sensitive recording type label sheet, a thermosensitive coloring layer containing the above-mentioned fluoran compound and the developer of the present invention is provided on one surface of the support, and the other surface of the support is provided with an adhesive layer. A release mount may be provided. In the case of a magnetic ticket paper, a magnetic recording layer containing a ferromagnetic material and a binder as main components may be provided instead of the release mount.

〔effect〕

The heat-sensitive recording material of the present invention has improved sensitivity, is suitable for high-speed recording, has high background whiteness, is excellent in storage stability, and has a stable image with little change over time.
It is extremely practical.

〔Example〕

Next, the present invention will be described in more detail with reference to examples. The parts and% shown below are based on weight.

[Synthesis of 4,4'-dichlorophenylsulfamide] p- was added to 500 ml of dry chloroform and 63.6 ml of dry pyridine.
100 g of chloroaniline was dispersed, cooled to -20 to -30 ° C, 31.8 ml of furfuryl chloride was added dropwise over 1.5 hours with stirring, and then the mixture was left at room temperature for 12 hours to complete the reaction. Next, the black solution was poured into 1200 ml of 2N acetic acid, the chloroform layer was extracted with N-caustic soda (200 ml × 3), and the extract was acidified with dilute acetic acid to precipitate crystals. After filtration and drying, melting point 121-122 ℃ by recrystallization with carbon tetrachloride.
White needle crystals were obtained.

Example 1 [Liquid A] 3- (N-methyl-N-cyclohexylamino) -6-
Methyl-7-anilinofluorane 20 parts 10% aqueous solution of hydroxyethyl cellulose 20 〃 water 60 〃 [solution B] 4,4'-dichlorophenylsulfamide 20 parts [Compound of compound example No. (2) (melting point 121- 122 ° C)] 4,4'-isopropylidenediphenol 20〃 10% aqueous solution of hydroxyethylcellulose 20〃 water 40〃 [liquid C] calcium carbonate 20 parts Methylcellulose 5% aqueous solution 20〃 water 60〃 then liquid A 10 parts, Liquid B 30 parts, liquid C 30 parts and isobutylene-
10 parts of a 20% aqueous solution of a maleic anhydride copolymer was mixed to prepare a thermosensitive color forming layer-forming liquid, which was applied to a fine paper having a basis weight of 50 g / m ² to give a dry adhesion of 4 to 5 g / m ^2. After coating and drying to provide a thermosensitive coloring layer, the surface smoothness is further 500 ~ 6
The thermosensitive recording material (a) was prepared by calendering the layer surface so that it would be 00 seconds.

Example 2 A thermosensitive recording sheet (b) was prepared in the same manner as in Example 1 except that the following liquid [D] was used instead of the liquid [B] of Example 1.
made.

[Compound Specific Example No. 3 compound, melting point 156-158 ° C]

4-Hydroxybenzoic acid benzyl ester 20 parts 10% aqueous solution of hydroxyethyl cellulose 20 parts water 40 parts Example 3 In Example 1, instead of the solution [A], the following solution [E],
A thermal recording sheet (c) was prepared in the same manner as in Example 1 except that the liquid [F] was used instead of the liquid [B].

[E] Liquid 3-diethylamino-6-methyl-7-anilinofluorane 20 parts 10% aqueous solution of hydroxyethyl cellulose 20〃 water 60〃 [F] Liquid diphenylsulfamide 20 parts [Compound Specific Example No. (1) Compound (melting point 109-110
° C)] 4,4'-Isopropylidene diphenol 20 parts 10% aqueous solution of hydroxyethyl cellulose 20〃water 40〃 Comparative Example 1 All were carried out except that [G] solution was used instead of [B] solution of Example 1. A thermal recording sheet (d) was prepared in the same manner as in Example 1.

[G] liquid 4,4'-isopropylidenediphenol 20 parts 10% aqueous solution of hydroxyethyl cellulose 20〃water 60〃 Comparative example 2 All operations were carried out except that [H] solution was used instead of [B] solution of Example 1. A thermal recording sheet (e) was prepared in the same manner as in Example 1.

[H] liquid 4-hydroxybenzoic acid benzyl ester 20 parts 10% aqueous solution of hydroxyethyl cellulose 20〃 water 60〃 The heat-sensitive sheets (a) to (e) obtained as described above were applied to a thermal inclination tester (manufactured by Toyo Seiki). Pressure 2 kg, contact time 1 second 1
Printed at 50 ° C.

In the storage stability test, printing was performed under the same conditions after 60 hours at 60 ° C.
The results are shown in Table-1.

Claims (1)

[Claims] 1. A thermosensitive recording material provided with a thermosensitive coloring layer containing a colorless or light-colored electron-donating dye and a developer, wherein at least one compound represented by the following general formula (I) is used as a developer. A heat-sensitive recording material characterized by using. (In the formula, R represents a hydrogen atom or a halogen atom.)