JPS62238787A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material having a high developed color density and a high color forming sensitivity, suitable for high-speed recording, having a high ground brightness and being extremely high in practicality, by using a specified ether compound as an auxiliary component, in a thermal recording material utilizing a color forming reaction between a leuco dye and a color developer. CONSTITUTION:An ether compound of general formula (I), wherein R is a 1-18C substd. or unsubstd. alkyl, substd. or unsubstd. aryl or aralkyl, is used as an auxiliary component, in a thermal recording material utilizing a color forming reaction between a leuco dye and a color developer. The ether compound has a high capability of dissolving color developers and leuco dyes widely used, when being heated. A thermal recording material having an arbitrary sensitivity can be obtained by controlling the melting point of the ether compound being used.

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 (particularly bisphenol A) 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 its advantages, it can be used for copying books, documents, etc.

It is useful as a recording material for various information and measuring instruments such as electronic computers, facsimiles, telex machines, and 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.

The phenolic compound itself is expensive and has little practical use. As a second method, for example, JP-A-53-3913
No. 9, JP-A-53-26139, JP-A-53-563
No. 6, JP-A No. 53-11036, etc., the heat-sensitive coloring layer contains various waxes, fatty acid amides, alkylated biphenyls, substituted biphenylalkanes, coumarins, diphenylamines, etc. with low melting points. There is a method of adding a melting substance as a sensitizer (or melting point depressant). However, the heat-sensitive recording materials produced based on these methods are still not sufficient in terms of color density, color sensitivity, background whiteness, etc.

〔the purpose〕

The purpose of the present invention is to achieve a color density of 1 and a sufficient color sensitivity.

Suitable for high-speed recording, and has high background whiteness.

It is an object of the present invention to provide a heat-sensitive recording material with extremely high practicality.

〔composition〕

The heat-sensitive recording material of the present invention is a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer.

It is characterized in that an ether compound represented by the following general formula (1) is used in combination as an auxiliary component.

(In the formula, R represents a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, a substituted or unsubstituted aryl group, or an aralkyl group.) This ether compound has a high ability to dissolve widely used color developers (electron-accepting compounds) and leuco dyes (electron-donating colorless dyes) when heated, and can adjust the melting point of the ether compound used in combination. Accordingly, a heat-sensitive recording material with arbitrary sensitivity can be obtained.

From the viewpoint of storage stability and sensitivity as a heat-sensitive recording material, the ether compound used in the present invention preferably has a melting point of 40 to 150°C, particularly preferably 50 to 120°C.

Specific examples of the ether compound of the present invention are shown below, but the present invention is not limited thereto.

Compound NO Structural Formula The leuco dyes used in the present invention can be applied singly or in combination of two or more types, 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(ρ-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-chlorophthalide.

3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran.

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-(N-ρ-toly-N-ditylamino)-6-methyl-7-anilinofluorane.

3-pyrrolidino-6-methyl-7-anilinofluorane.

2-(N-(3'-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)fluorane.

3-dibutylamino-7-(0-chloroanilino)fluoran.

3-N-methyl-N-isoamylamino-6-methyl-
7-7nilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-7nylinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N,N-diethylamino)- 5-methyl-7-(
N.

N-dibenzylamino)fluoran.

Benzoylleucomethylene blue, 6'-chloro-a'-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-trifluoro methylanilino) fluorane.

3-pyrrolidino-7-(di-p-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)fluoran, 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, etc. are preferably used, and the specific examples thereof are as follows. Give an example.

4.4'-isopropylidene 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)
, 2.2'-methylenebis(4-methyl-6-tert-butylphenol).

2.2'-methylenebis(4-ethyl-6-tert-butylphenol), 4.4'-butylidenebis(6-7ert-butyl-2
methyl)phenol, 4.4'-thiobis(6-t,crtbutyl-2-methyl)phenol, 4.4'-diphenolsulfone.

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, 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-〇-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, calcium, etc.

In the present invention, the leuco dye, color developer, and auxiliary components are bonded and supported on a support.

Various conventional binders can be used as appropriate, for example,
Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate,
Polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/meth, acrylic acid ternary copolymer, styrene/maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer In addition to water-soluble polymers such as combined alkali salts, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic acid ester, and vinyl chloride/vinyl acetate copolymer Latexes such as polymers, polybutyl methacrylate, ethylene/vinyl acetate copolymers, styrene/butadiene/acrylic copolymers, etc. can be used.

In the present invention, in addition to the leuco dye, color developer, and auxiliary components, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible A sexual substance (or lubricant), etc. can be used in combination. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, tin hydroxide, barium sulfate, clay, talc, and surface-treated inorganic fine powders such as calcium and silica. ,
Examples include organic fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin.

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

〔effect〕

The heat-sensitive recording material of the present invention has improved sensitivity, is suitable for high-speed recording, and has a 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 [Liquid A] 3-(N-methyl-N-cyclohexyl 20 parts amino)-6-methyl-7-anilitufluoran 10% of hydroxyethyl cellulose 20I! aqueous solution water
601! [Liquid B] Bisphenol A 20 parts 10% of hydroxyethyl cellulose 20 Aqueous solution
60/! [Liquid C] P-benzyloxybenzyl alcohol 20 parts (Compound of Compound Example No. 1, melting point 83-84°C) 5% aqueous solution of methylcellulose 20 parts Water
601! [D
Liquid] Calcium carbonate 20 parts Methyl cellulose 5% aqueous solution 20 parts Water
60/
! Next, 10 parts of liquid A, 30 parts of liquid B, 30 parts of liquid C, and 20 parts of liquid D.
part and 20% of isobutylene-maleic anhydride copolymer
A thermosensitive coloring layer forming solution was prepared by mixing 10 parts of an alkaline aqueous solution, and this was coated and dried on high-quality paper with a basis weight of 50 g/rd so that the dry adhesion amount was 4 to 5 g/rri' to form a thermosensitive coloring layer. After that, the surface smoothness is further increased from 500 to 600.
A heat-sensitive recording material (a) was prepared by calendering the surface of the layer to a temperature of 10 seconds.

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

(E) Liquid P-hydroxybenzoic acid benzyl ester 20 parts 10% aqueous solution of hydroxyethylcellulose 20 parts water
60
//Example 3 Thermal recording material (C) was prepared in the same manner as in Example 1 except that the following liquid [F] was used instead of the CB) liquid in Example 1.
It was created.

[F liquid]

1,7-bis(4-hydroxyphenylthio)-3,5
-Dioxahebutane 20 parts 10% aqueous solution of hydroxyethyl cellulose 20 parts Water
60 Comparative Example 1 Example 1 except that water was used instead of liquid (C) in Example 1.
A thermosensitive recording material (d) was prepared in the same manner as above.

Comparative Example 2 A heat-sensitive recording material (e) was produced in the same manner as in Example 2 except that water was used instead of liquid (C) in Example 2.

Comparative Example 3 A heat-sensitive recording material (f) was prepared in the same manner as in Example 3 except that water was used instead of liquid (C) in Example 3.

Comparative Example 4 A heat-sensitive recording material (g) 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 stearamide 20 parts 5% aqueous solution of methylcellulose 20/l water
60/
I Comparative Example 5 A heat-sensitive recording material (h) was prepared in the same manner as in Example 2, except that the liquid CG) was used instead of liquid (C) in Example 2.

Comparative Example 6 A thermosensitive recording material (i) was obtained in the same manner as in Example 3, except that the liquid (G) was used instead of the liquid (C) in Example 3.

The heat-sensitive recording materials (a) to (i) obtained as described above are
Using a thermal printing experimental device with a thin film head made by Matsushita Electronics Co., Ltd., the pulse width was set to 1 with a head power of 0.45 sp/dot, a recording time of 1 line of 20 m5 ec/Q, and a scanning line density of 8 x 3.85 dots/m+s. .6.2.0.2.4
(msec), and the print density was measured using a Macbeth densitometer RD-514 (filter 1+1-106). The results are shown in Table-1.

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

Table 2 From the above results, it can be seen that the heat-sensitive recording material of the present invention has high color development sensitivity, is suitable for high-speed recording, and also has high background whiteness, 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, there are general formulas, ▲mathematical formulas, chemical formulas, tables, etc. as auxiliary components▼ (where R is 1 to 1 carbon atoms) 18) represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or an aralkyl group.