JPS62242588A - Thermal recording material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 color-forming dye such as a leuco dye as a color-forming agent, and a phenolic compound (especially bisphenol A) as a color-developing agent to cause the dye to develop specific heat color. For example, a heat-sensitive coloring layer is provided in which a coloring system made of an acidic substance such as an organic acid is further dispersed with a binder, a filler, a sensitivity improver, a lubricant, and other auxiliary agents.

Special Publication No. 43-=1160, Special Publication No. 45-1/1039
No. 48-27736, and 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). Therefore, 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.
Due to its advantages of low noise generation, low environmental pollution, and low cost, it is used for copying books, documents, etc., as well as for recording various information and measuring instruments such as computers, facsimiles, telex machines, medical measuring instruments, etc. Useful as a material.

On the other hand, in recent years, along with the development of society, there has been an increasing demand for higher speed and higher density recording. 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 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. 0, JP-A-53-26130, 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, it cannot be said that the heat-sensitive recording materials produced based on these methods are still sufficient in terms of color density, color sensitivity, background whiteness, etc.

〔the purpose〕

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

〔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, and is characterized in that it uses an ether compound represented by the following general formula (T) as an auxiliary component.

(wherein, R is a straight chain, branched or cyclic divalent hydrocarbon group,
n represents an integer of 1-2. ) The ether compound represented by the general formula (1) used in combination as an auxiliary component in the present invention is a mixture of widely used color developers (electron-accepting compounds) and leuco dyes (electron-donating colorless dyes) when heated. By adjusting the melting point of the ether compound used in combination, a heat-sensitive recording material with a desired 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 side Structural formula The leuco dyes used in the present invention may be applied singly or in combination of two or more types, but such leuco dyes include:
The following materials are optionally applied to this type of heat-sensitive material, such as triphenylmethane-based, fluoran-based,
Leuco compounds of dyes such as phenothiazine, auramine, spiropyran, and indolinophthalide are preferably used.

A specific example of such a leuco dye is I.

Examples 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-diethylaminophenyl, 3.3-bis(P-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(1)-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-(N-p-tolyl-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-chloromethylanilino)fluoran.

3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 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.

Benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylosbilane, 6'-bromo-3'-methoxy-benzoindolino-pyrylosbilane.

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, ]-(2'-methoxy-4'-dimethylaminophenyl)-3-( 2'-hydroxy-4'-chloro-51
-methylphenyl)phthalide, 3-morpholino-7-(N-propyltrifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-( N-benzyl-1-lifluoromethylanilino)fluorane.

3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-t-luidino) )-7-(α-phenylethylamino)fluoran.

3-diethylamino-? -(o-methoxycarbonylphenylamino)fluoran.

3-Diethylamino-5-methyl-7-(α-)engineered methylethylamino)fluoran.

3-diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(p-n
-butylanilino)fluorane, 3-(N-benzyl-N-cyclohexylamino)-5
,6-pendi-two-α-naphthylamino-4'-bromofluorane.

3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N-(2-ethoxypropyl)aminol 6-methyl-furanilifluorane, 3-N-ethyl-N-tetrahydrofurfuryl Amino-6-methyl-
7-anilinofluorane.

3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc.

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(O-methylphenol)
.

4.4″-Secondary-butylidene bisphenol4.
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-t,crt-butyl-
2 methyl) phenol.

4.4'-thiobis(6-tert, butyl-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, l-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/,! ! In addition to water-soluble polymers such as water-maleic acid copolymer alkali salts, isobutylene-maleic anhydride copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, and styrene/butadiene copolymers , polyacrylic acid, polyacrylic ester, vinyl chloride/vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer, etc. latex. I can do it.

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, zinc 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 is 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 Paper 1 synthetic paper or a plastic film, and drying the coating solution. In this case, the amounts of leuco dye, color developer, and color development sensitivity increasing agent used are 5 to 40% by weight and 20% by weight, respectively.
~60% by weight, 20-60! IK amount % is appropriate.

〔effect〕

The heat-sensitive recording material of the present invention has improved sensitivity, x
It is suitable for 6-speed recording, has high background whiteness, and is 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 hydroxyethylcellulose 20〃Aqueous solution water
60〃[Liquid B] Bisphenol A 20 parts 10% of hydroxyethyl cellulose 20'〃Aqueous solution water
60Il [Liquid C] 2-(β-naphthyloxy)ethanol 20 parts (compound of specific compound example No. 3, melting point 78-79°C) 5% aqueous solution of methylcellulose 20 parts water
60 copies [D
Liquid] Calcium carbonate 20 parts Methyl cellulose 5% aqueous solution 20n water
Next, 10 parts of liquid A, 30 parts of liquid N, 30 parts of liquid C, 20 parts of liquid D, and 10 parts of a 20% alkaline aqueous solution of isobutylene-maleic anhydride copolymer were mixed to prepare a thermosensitive coloring layer forming liquid. The basis weight of this is 50 g/n (the dry adhesion amount is 4 to 5 on high-quality paper).
After coating and drying to provide a heat-sensitive color forming layer, the layer surface was further calendered to have a surface smoothness of 500 to 600 seconds to prepare a heat-sensitive recording material (o).

Example 2 A thermosensitive recording material (
b) was created.

(E) Liquid P-hydroxybenzoic acid benzyl ester 20 parts 10% aqueous solution of hydroxyethylcellulose 20 parts water
5
Qtt Example 3 A heat-sensitive recording material (C) was prepared in the same manner as in Example 1 except that the following liquid (F) was used instead of the [mouth] 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 Sharp/J except that water was used instead of liquid (C) in Example 3.
- A thermosensitive recording material (f) was prepared in the same manner as 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 methyl cellulose 20 Il water
60/!
Comparative Example 5 A heat-sensitive recording material (h) was prepared in the same manner as in Example 2, except that the above liquid [G] 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 manufactured by Drop Electronic Components@, the head power was 0.451/dot, the recording time per line was 20m5ec/Q, and the scanning line density BX was 3.85dot1.
The pulse width was set to 1.6.2 under the conditions of 11. Q, 2.4 (ms
ec), and the print density was measured using a Macbeth densitometer R-Rho 514 (filter υ-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, the heat-sensitive recording material of the present invention has high color development sensitivity 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.▼ (wherein R is a straight chain, 1. A heat-sensitive recording material characterized in that an ether compound represented by a branched or cyclic divalent hydrocarbon group (n represents an integer of 1 to 2) is used in combination.