JPS63130383A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance developed color density, color forming sensitivity and ground brightness, by jointly using a triphenyl compound of formula (1) as an auxiliary component in a thermal recording material utilizing a color forming reaction between a leuco dye and a color developer therefor. CONSTITUTION:In formula (1), R is a saturated or unsaturated hydrocarbon group, each of X, Y and Z, which may be the same or different, is a halogen, alkyl or alkoxyl, and each of l, m and n is independently an integer of 0-3. A triphenyl compound of formula 91) has a high ability to dissolve widely used color developers and leuco dyes when being heated, so that a thermal recording material with an arbitrary sensitivity can be obtained by controlling the melting point of the compound. It is particularly preferable that the compound has a melting point of 50-120 deg.C, from the viewpoints of preservation stability and sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive recording material, and particularly to a heat-sensitive recording material with excellent color development.

[Prior art]

General heat-sensitive recording materials are coated on a support such as paper or film, and contain a colorless or light-colored dye such as a leuco dye as a color former, and a phenolic compound (especially bisphenol^) as a color developer to make the color develop when heated. A heat-sensitive coloring layer in which a binder, a filler, a sensitivity improver, a lubricant, and other auxiliary agents are further dispersed in a coloring system made of an acidic substance such as an organic acid is provided. Kosho 45-14
No. 039 and Japanese Patent Application Laid-Open No. 48-27736, it has been widely put into practical use. This type of thermal recording sheet produces a colored image through an instantaneous chemical reaction between a coloring agent and a color developer during heating (a thermal printer or facsimile machine with a built-in thermal head is used for heating). because there is,
Compared to other recording materials, records can be obtained in a short time using relatively simple equipment without complicated processing such as development and fixing, there is less noise generation and environmental pollution, and the cost is low. Due to the advantages of
It is useful as a recording material for various information and measuring instruments such as medical measuring instruments.

On the other hand, in recent years, along with the development of society, the demand for higher speed and higher density recording 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 recording materials that can handle this. The first method is to lower the melting point of the electron-accepting compound used as the color developer to a practically acceptable level (e.g., 80 to 120°C) and lower the melting point with the leuco dye. The objective is to reduce the speed and speed up the process. However, it is difficult to control the melting point of phenolic compounds, which are color developers that are currently widely used in the field of heat-sensitive recording materials, and the phenolic compounds themselves are expensive, making them impractical. The second method is, for example, as described in JP-A-53-39139, JP-A-53-26139, JP-A-53-5636, JP-A-53-11036, etc.
There is a method in which a heat-melting substance with a low melting point, such as various wax moieties, fatty acid amides, alkylated biphenyls, substituted biphenyl alkanes, coumarins, and diphenylamines, is added to the heat-sensitive coloring layer as a sensitizer (or melting point depressant).

However, it is difficult to say that the thermosensitive recording materials produced by fM based on these methods are sufficient in terms of single color density, single color sensitivity, background whiteness, etc.

〔the purpose〕

An object of the present invention is to provide an extremely practical heat-sensitive recording material that has sufficient single color density and color sensitivity, is suitable for high-speed recording, and has a high background whiteness.

〔composition〕

The heat-sensitive recording material of the present invention is characterized in that it uses a triphenyl compound represented by the following general formula (1) as an auxiliary component in a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and its color developer. shall be.

(In the formula, R is a saturated or unsaturated hydrocarbon group.

X, Y and Z represent a halogen atom, an alkyl group, an alkoxyl group, X, Y and Z may be the same or different, and Q, rm and n each independently represent an integer from 0 to 3.) The triphenyl compound represented by the general formula (I) used in combination as an auxiliary component in the present invention contains a widely used color developer (electron-accepting compound) and leuco dye (1! child-donating colorless dye). It has a high ability to dissolve when heated, and by adjusting the melting point of the triphenyl compound used in combination, a heat-sensitive recording material with any sensitivity can be obtained.

The triphenyl compound used in the present invention has a melting point of 40-150°C from the viewpoint of storage stability and sensitivity as a heat-sensitive recording material.
Those with a temperature of 50 to 120°C are particularly preferred. Specific examples of the triphenyl compound of the present invention are shown below, but the present invention is not limited thereto.

Kayatsu Nα Structural formula The leuco dyes used in the present invention can be applied singly or in a mixture of two or more, but such leuco dyes include:
Those applied to this type of heat-sensitive material can be arbitrarily applied. For example, leuco compounds of dyes such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based 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-dibutylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorphthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlor Fluoran, 3-dimethylamino-5,7-dimethylfluoran, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-U-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane.

2-(N-(:l'-trifluoromethylphenyl)
amino)-6-dinithylaminofluorane, 2-(3
, 6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam).

3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-N -Methyl-N-ynylamino-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)fluoran, Benzoylleucomethylene blue.

6'-Chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane.

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-ρ-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7 -(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)-7-(α-phenylethylamino)fluoran.

3-diethylamino-7-(O-methoxycarbonylphenylamino)fluoran.

3-diethylamino-5-methyl-7-(α-phenylethylamino)fluorane, 3-diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(p-ropethylanilino)fluoran.

3-(N-benzyl-N-cyclohexylamino)-5
, 6-penzo7-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.

As the color developer used in the present invention, various electron-accepting compounds 1 such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof are preferably used.

Specific examples thereof are shown below. 6 4.4'-Impropylidene bisphenol, 4.4
′ -isopropylidene bis(0-methylphenol)
.

4.4'-Secondary-butylidene bisphenol 4
．． 4'-isopropylidene bis(2-tert-butylphenol), 4.4'-cyclohexylidene diphenol, 4.4
′ -isopropylidene bis(2-chlorophenol)
.

2t2'-methylenebis(4-methyl-6-tert-butylphenol), 2.2'-methylenebis(4-ethyl-6-tert-butylphenol).

4.4'-Butylidene bis(6-tertbutyl-2
methyl)phenol, 4.4'-thiobis(6-tertbutyl-2-methyl)phenol, 4.4'-diphenolsulfone, 4.4'-diphenol sulfoxide, isopropyl P-hydroxybenzoate, P -Benzyl hydroxybenzoate, benzyl protocatechuate, stearyl gallate.

lauryl gallate, Octyl gallate.

1,7-bis(4-hydroxyphenylthio)-3,5
-Dioxahebutane.

1.5-bis(4-hydroxyphenylthio)-3-oxapentane, 1.3-bis(4-hydroxyphenylthio)-propane, 1.3-bis(4-hydroxyphenylthio)-2-hydroxy propane.

N,N'-diphenylthiourea.

N,N'-di(m-chlorophenyl)thiourea.

salicylanilide, 5-chloro-salicylanilide, salicyl-〇-chloroanilide, 2-Hydroxy-3-naphthoic acid.

2-hydroxy-1-naphthoic acid, -hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum, calcium, etc.

In the present invention, in order to bind and support the leuco dye, color developer and auxiliary components on the support, various conventional binders can be used as appropriate, such as polyvinyl alcohol, starch and its derivatives, methoxy Cellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose and other cellulose derivatives, sodium polyacrylate, polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid ternary copolymer , 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, polyurethane, styrene-butadiene. Copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride/
Latexes such as vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinyl acid copolymer, and styrene/butadiene/acrylic copolymer can be used.

Furthermore, in the present invention, in addition to the leuco dye, color developer, and auxiliary components, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, may be used in combination, if necessary. In this case, the filler may be, for example,
Calcium carbonate, silica, zinc Mide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay,
Examples include inorganic fine powders such as talc, surface-treated calcium and silica, and organic fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin.

The heat-sensitive recording material of the present invention is produced, for example, by applying a coating liquid for forming a heat-sensitive layer containing the above-mentioned components onto a suitable support such as paper, synthetic paper, or plastic film, and drying the coated liquid. In this case, the amounts of the leuco dye, color developer, and coloring sensitivity enhancer used are 5 to 40% by weight and 20 to 40% by weight, respectively.
60% by weight, preferably 20-60% by weight.

〔effect〕

The heat-sensitive recording material of the present invention has improved sensitivity, is suitable for high-speed recording, and has high background whiteness, making it extremely practical.

〔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.

Example 1 [Δ liquid] 10% aqueous solution water
60/1 [Liquid B] Bisphenol A 20 parts 10% aqueous solution of polyvinyl alcohol 20n water

60nCC liquid] Polyvinyl alcohol 10% aqueous solution '1Qtr
water
601I [Liquid D] Calcium carbonate 20 parts Methyl cellulose 5% aqueous solution 201/water

60 no! Next, 10 parts of liquid A, 30 parts of liquid B, 30 parts of liquid C, 20 parts of liquid D, and 10 parts of a 20% alkaline aqueous solution of inbutylene-maleic anhydride copolymer were mixed to prepare a thermosensitive coloring layer forming liquid. Basis weight 50g/
After coating and drying the heat-sensitive coloring layer on high-quality paper to a dry adhesion weight of 4 to 5 g/m, the layer surface was further calendered to achieve a surface smoothness of 500 to 600 seconds. A thermosensitive recording material (a) was prepared.

Example 2 Thermal recording material (b) was prepared in the same manner as in Example 1 except that the following liquid [E] was used instead of liquid [C] in Example 1.
It was created.

(E) Liquid polyvinyl alcohol 10% water in2 20n
water
6Qrr Example 3 A thermosensitive recording material (C
)It was created.

[F liquid]

10% aqueous solution of polyvinyl alcohol iQn water

6II Example 4 A heat-sensitive recording material (d) was prepared in the same manner as in Example 1 except that the following liquid (G) was used instead of liquid (C) in Example 1.

[G liquid]

10% aqueous solution of polyvinyl alcohol 201I
water
60! ! Comparative Example 1 Example 1 except that water was used instead of liquid [C] in Example 1.
A thermosensitive recording material (e) was prepared in the same manner as above.

Comparative Example 2 A heat-sensitive recording material (f) was prepared in the same manner as in Example 1 except that the following [old solution] was used instead of [C) solution of Example 1.

[H) Liquid stearamide 20 parts 5% aqueous solution of methyl cellulose 'lQn water
6
011 Heat-sensitive recording materials (a) to (f) obtained as above
)of.

Using a thermal printing experimental device equipped with a thin film head manufactured by Matsushita Electronics Co., Ltd., the pulse width was set to 1.5 mm under conditions of head power of 0.451/dot, 1 line recording time of 20 m5 ec/Q, and scanning line density of 8 x 3.85 dot/mm. 6.2, 0.2.4 (
msec), and the print density is measured using Macbeth Densitometer R.
Measured with D-514 (filter W-106). The results are shown in Table-1.

Table 1 Next, the heat-sensitive recording materials (a) to (f) were subjected to a 24-hour storage test under dry conditions at 60 DEG C., and changes in skin density were examined. The results are shown in Table-2.

Table 2 From the above results, the color development sensitivity of the heat-sensitive recording material of the present invention is
, and is suitable for high-speed recording.

It can be seen that the background whiteness is high, making it an extremely practical heat-sensitive recording material.

Claims (1)

[Claims] (1) In heat-sensitive recording materials that utilize the color-forming reaction between leuco dye and its color developer, auxiliary components include general formulas, ▲mathematical formulas, chemical formulas, tables, etc.▼ (where R is saturated or unsaturated. The hydrocarbon group of
Y and Z represent a halogen atom, an alkyl group, or an alkoxyl group, and X, Y, and Z may be the same or different;
, m and n each independently represent an integer of 0 to 3. ) A heat-sensitive recording material characterized in that it uses a triphenyl compound represented by: