JPH011584A - heat sensitive 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 that has sufficient color development sensitivity and color density, and has a high background whiteness.

[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 heat-sensitive 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, recording 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 these advantages, it is useful not only for copying books, documents, etc., but also 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 faster recording and higher density of descendants 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 a color developer to a practically acceptable level (e.g., 80 to 120°C).
Second, the melting start temperature with the leuco dye is lowered and the melting speed is increased. 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-53-39.1
No. 39, JP-A-53-26139, JP-A-53-56
As described in No. 36, JP-A-53-11036, etc., various waxes, fatty acid amides, alkylated biphenyls, substituted biphenylalkanes,
There is a method of adding a low melting point heat-melting substance such as coumarins or diphenylamines as a sensitizer (or melting point depressant). However, it cannot be said that the heat-sensitive recording materials produced based on these methods are sufficient in terms of color density, color sensitivity, background whiteness, image stability, etc.

〔the purpose〕

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

〔composition〕

According to the present invention, a carbonate ester compound represented by the following general formula [1] or (II) is used as an auxiliary component to improve sensitivity in a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer. A heat-sensitive recording material is provided.

However, in the formula, R represents an alkyl group or an aryl group, V,
X, Y and 2 each represent an alkyl group, an alkoxy group or a halogen atom, and Q, m and n each represent an integer of 0-3.

The carbonate ester compound represented by the above general formula used as an auxiliary component to improve sensitivity in the present invention contains a widely used color developer (electron-accepting compound) and leuco dye (electron-donating colorless dye). It has a high ability to dissolve when heated,
By adjusting the melting point of the carbonate ester compound used, a heat-sensitive recording material with any sensitivity can be obtained.

From the viewpoint of storage stability and sensitivity as a heat-sensitive recording material, the carbonate JS 11.1' compound used in the present invention has a melting point of 40 to
A temperature of 150°C is preferable, and a temperature of 50 to 120°C is particularly preferable. Specific examples of carbonate ester compounds used in the present invention are shown below, but the present invention is not limited thereto.

Compound Nα Structural formula The leuco dyes used in the present invention may be applied singly or in a mixture of two or more types, but as such leuco dyes, those applied to this type of heat-sensitive material can be arbitrarily applied. For example, triphenylmethane type, fluoran type, phenothiazine type, auramine type, spiropyran type,
Leuco compounds of dyes such as indolinophthalide 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-dimethylaminophthalide (also known as crystal violet lactone) -dimethylaminophenyl)-6-dibutylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6 -Chlorfluorane, 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-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-
chloranilino)xantylbenzoic acid lactam), 3-
Diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran.

3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(0-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)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-31-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-(N-ethyl-N-i-amyl)amino-6-methyl-7-anilinofluorane, 3-(N-methyl-N-isopropyl)amino-6-methyl-7 -anilinofluorane, 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)fluoran, 3-diethylamino-7 -Piperidinofluorane.

2-chloro-3-(N-methyltoluidino)-7-(p
-〇-butylanilino)fluorane, 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 etc.

Further, as the color developer used in the present invention, various electron-accepting compounds such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof, etc. are preferably used, and specific examples thereof Examples include the following.

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'-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, benzyl P-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate.

Octyl gallate, ■, 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, ■-hydroxy-2-naphthoic acid, zinc and aluminum of hydroxynaphthoic acid.

Metal salts such as calcium.

In the present invention, various conventional binders can be used as appropriate to bind and support the leuco dye, color developer, and auxiliary components on the support.

For example, polyvinyl alcohol, starch and its derivatives,
Cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic acid ester copolymer, acrylamide/acrylic acid ester/methacrylic acid terpolymer, styrene/ In addition to water-soluble polymers such as maleic anhydride copolymer alkali salts, isobutylene/maleic anhydride copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate and polyurethane.

Emulsions such as polyacrylic acid, polyacrylic ester, vinyl chloride/vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene copolymer, styrene/butadiene/acrylic copolymer, etc. latex, etc.

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. ,
Organic fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin can be mentioned, and examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts. In addition, various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, 3,4
-Epoxy-dialkyl hexahydrophthalate, higher ketones, other thermofusible organic compounds, etc. at 50-200℃
Examples include those having a melting point of about .

In addition, in the present invention, between the support and the thermosensitive coloring layer,
If necessary, a layer containing a filler, a binder, a thermofusible substance, etc. may be provided as an undercoat layer. In this case, specific examples of fillers, binders and thermofusible substances include:
The same materials as those exemplified in the heat-sensitive coloring layer may be mentioned.

Furthermore, in the heat-sensitive recording material of the present invention, a protective layer can be provided on the heat-sensitive coloring layer for the purpose of improving matching properties with a thermal head etc. and further enhancing recorded image storage stability. In this case, the above-mentioned fillers, binders, surfactants, and thermofusible substances can also be used as components constituting the protective layer.

The heat-sensitive recording material of the present invention can be produced, for example, by applying a coating solution for forming a heat-sensitive coloring layer containing each of the above-mentioned components onto a suitable support such as paper, synthetic paper, or plastic film, and drying the coating solution. . In this case, leuco dye, color developer,
The amount of sensitivity improver used is 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 The following mixtures were each ground in a magnetic ball mill for 2 hours to prepare [Liquid A], [Liquid B], [Liquid C], and [Liquid D].

cA solution] 10% aqueous solution of polyvinyl alcohol 20 parts water

60 parts [Liquid B] Bisphenol A 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water

60 parts [Liquid C] 10% aqueous solution of polyvinyl alcohol 20 parts water
60 parts [Liquid D] Calcium carbonate 20 parts 5% aqueous solution of methylcellulose 20 parts Water
60
Parts: [Liquid A] 10 parts, [Liquid B 330 parts, cC liquid 330 parts]
1 part, 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, and this was coated on high-quality paper with a basis weight of 50 g/rd to a dry adhesion amount. is 4 to 5 g/n (after coating and drying to form a heat-sensitive coloring layer, the layer surface is further calendered to have a surface smoothness of 500 to 600 seconds to prepare heat-sensitive recording material (a). did.

Example 2 A heat-sensitive recording material (b) was prepared in the same manner as in Example 1 except that the following cE liquid] was used as a filler for the CC liquid of Example I.
It was created.

[Liquid E]

10% aqueous solution of polyvinyl alcohol 20 parts water

60 parts Example 3 A thermosensitive recording material (C
)It was created.

[F liquid]

10% aqueous solution of polyvinyl alcohol 20 parts water
60 parts Comparative Example 1 A heat-sensitive recording material (d) was prepared in the same manner as in Example 1, except that water was used instead of [liquid C] in Example 1.

Comparative Example 2 A heat-sensitive recording material (e) was produced 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]

Stearic acid amide 20 parts 3-aqueous solution of methylcellulose 20 parts water
60 copies or more of the heat-sensitive recording materials (a) to (e) obtained as described above were printed using a heat-sensitive printing experimental device equipped with a thin-film head manufactured by Matsushita Electronic Components Co., Ltd. at a head power of 0.45 W/dot and a recording time of one line. 20m5ec/ (1, scanning line density 8 x 3.85
The pulse width was set to 1.6, 2.0 and 2 under the conditions of dots/mm.
．． Printing was performed at 4 m5ec, and the print density was measured using a Macbeth densitometer RD-514 (filter W-106). The results are shown in Table-1.

Table 1 Next, heat-sensitive recording materials (a) to (e) 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, the heat-sensitive recording material of the present invention has high color development sensitivity;
It can be seen that it is suitable for high-speed recording, has a high background whiteness, and is an extremely practical heat-sensitive recording material.

Claims (1)

[Claims] (1) In a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and its color developer, the general formula [
I] or [II], ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[II] (In the formula, R is an alkyl group or an aryl group, W, X, Y
and Z represents an alkyl group, an alkoxy group, or a halogen atom, and k, l, m, and n each represent an integer of 0 to 3.