JPH0197683A - Thermosensitive 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 more particularly to a leuco dye that is colorless or slightly light-colored at room temperature.

The present invention relates to an improvement in a heat-sensitive recording material provided on a support with a heat-sensitive color-forming layer containing as a color-forming component a color developer which reacts with the leuco dye under heat to form a color.

[Prior art]

Thermosensitive recording materials generally have a thermosensitive coloring layer containing a thermochromic composition as a main component on a support such as paper, synthetic paper, or plastic film.
A colored image can be obtained by heating with a strobe lamp or the like. Compared to other recording materials, this type of recording material
It has the advantages of being able to obtain records in a short time with a relatively simple device without complicated processes such as fixing, generating less noise and polluting the environment, and being inexpensive.
In addition to being used for copying books, documents, etc., it is also widely used as a recording material in a wide variety of applications, including electronic computers, facsimile machines, ticket vending machines, labels, and recorders. The thermochromic composition used in such heat-sensitive recording materials consists of a general coloring agent and a color developer that causes the coloring agent to develop color when heated.
Colorless or light-colored leuco dyes having a lactone, lactam or spiropyran ring have been used as color formers, and organic acids and phenolic substances have been used as color developers. A recording material made of a combination of a color forming agent and a color developing agent has the advantage that the obtained image has a particularly clear color tone, has a high background whiteness, and has excellent weather resistance. , is widely used.

Conventionally, bisphenol A and P-hydroxybenzoic acid esters have been used as color developers for leuco dyes, but although these phenols have a high color density, they lack the stability of colored images, so they cannot be left alone. It has the disadvantage that the concentration decreases, and the concentration decreases at high temperatures or at high temperatures.

On the other hand, JP-A-51J-145189 and JP-A No. 59-145
As described in Japanese Patent No. 190, it has been proposed to use a metal salt of an organic acid as a color developer, but although this product has good stability, it has the drawback of poor sensitivity.

〔the purpose〕

The present invention overcomes the problems of the prior art. That is, the object of the present invention is to provide a heat-sensitive recording material that has high sensitivity, little deterioration over time, and improved reliability.

(Structure) According to the present invention, in a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer, the color developer is at least one type of compound represented by the following general formula. A heat-sensitive recording material is provided.

(In the formula, R1 represents a hydrogen atom or a methyl group, R2 represents a lower alkylene group, and n represents an integer of 1-3, respectively.) That is, the heat-sensitive recording material of the present invention uses the above general formula as a color developer. Since at least one of the compounds shown above is used, it is highly sensitive and the recorded image has extremely little deterioration over time.

Examples of the color developer represented by the general formula used in the present invention include compounds such as those shown below.

p-hydroxybenzoic acid (2-acryloyloxy) ethyl ester, p-hydroxybenzoic acid (2-methacryloyloxy)
Ethyl ester, P-hydroxybenzoic acid (3-acryloyloxy) propyl ester, p-hydroxybenzoic acid (3-methacryloyloxy)
propyl ester.

3.4-dihydroxybenzoic acid (2-acryloyloxy)ethyl ester.

3.4-dihydroxybenzoic acid (2-methacryloyloxy) ethyl ester.

3.4-dihydroxybenzoic acid (3-acryloyloxy) propyl ester, 3.4-dihydroxybenzoic acid (3-methacryloyloxy) propyl ester.

2.4-dihydroxybenzoic acid (2-acryloyloxy)ethyl ester.

2.4-dihydroxybenzoic acid (2-methacryloyloxy) ethyl ester, 2.4-dihydroxybenzoic acid (3-acryloyloxy) propyl ester.

2.4-dihydroxybenzoic acid (3-methacryloyloxy) propyl ester, gallic acid (2-acryloyloxy) ethyl ester, gallic acid (2-methacryloyloxy) ethyl ester, gallic acid (3-acryloyloxy) propyl ester, gallic acid Acid (3-methacryloyloxy)propyl ester, etc.

These compounds are used in an amount of 0.5 parts by weight per 1 part by weight of leuco dye.
It is preferable to use the amount in the range of -10 parts by weight.

The leuco dyes used in the present invention may be applied singly or in a mixture of two or more types. As such leuco dyes, those applied to this type of heat-sensitive material may be arbitrarily applied. For example, triphenyl Methane type, fluorane type, phenothiazine type.

Leuco compounds of dyes such as auramine, spiropyran, and 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-dibutylaminophenyl.

3.3-Bis(P-dimethylaminophenyl)-6-chlorphthalide.

3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3
-N-methyl-N-isobutyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluorane, 3-diethylamino-7-chlorofluorane , 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane.

3-diethylamino-6-methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ethylamino)-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)xantylbenzoinated lactam), 3-diethylamino-6-methyl-7-(o-trichloromethylanilino)fluoran.

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

3-N-methyl-N-amylamino-6-methyl-7-
Anilino 2-fluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane.

3-diethylamino-6-methyl-7-(2', 4'
-dimethylanilino)fluoran, 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-41-dimethylaminophenyl)-3-(2'-methoxy -5'-nitrophenyl) phthalide, 3-(2'-hydroxy-4'-die thylaminophenyl)-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)fluoran, 3-(N-ethyl-P-toluidino)-7-(α-phenylethylamino)fluoran.

3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethyl, amino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-piperidinofluorane, 2 −
Chloro-3-(N-methyltoluidino)-7-(p-n
-butylanilino)fluorane.

3- (N-methyl-N-isopropylamino)-6-
Methyl-7-anilinofluorane.

3-dibutylamino-6-methyl-7-anilinofluorane.

3.6-bis(dimethylamino)fluorene spiro(9
゜3')-6'-dimethylaminophthalide, 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-fumesitidino 4', 5'-benzofluorane, and the like.

When the leuco dye and the color developer are bonded and supported on a support in order to produce the heat-sensitive recording material of the present invention, various commonly used binders can be used as appropriate, and specific examples thereof include, for example, These include:

Polyvinyl alcohol, starch and its derivatives, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, cellulose derivatives such as ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic ester copolymer, acrylamide/acrylic ester/methacrylic In addition to water-soluble polymers such as acid ternary copolymers, styrene/maleic anhydride copolymer alkali salts, isobutylene/maleic anhydride copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate , polyurethane, polyacrylic acid, polyacrylic acid ester, polymethacrylic acid ester, vinyl chloride-vinyl acetate copolymer, ethylene/vinyl acetate copolymer, and other emulsions, and styrene/butadiene copolymer.

Latex such as styrene-butadiene/acrylic copolymer.

In addition, in the present invention, in addition to the leuco dye and the color developer, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible substances (or lubricants), may be used. ), a pressure coloring inhibitor, 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. , urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, and other organic fine powders. Examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts, various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, , 4-epoxy-dialkyl hexahydrophthalate, higher ketones, p-benzylbiphenyl, benzyl p-benzyloxybenzoate, and other thermofusible organic compounds with melting points of about 50 to 200°C. It will be done.

Furthermore, in the present invention, it is possible to use a conventionally known color developer as necessary, and specific examples of such a color developer include:
For example, °bis(4-hydroxyphenyl)sulfone,
Benzyl p-hydroxybenzoate, tetrabromobisphenol S, tetrabromobisphenol A, 1,1
, 3-tris(4-hydroxy-2-methyl-5-tert-butylphenyl)butane, bis(2-methyl-
Examples include 4-hydroxy-5-tert-butylphenyl) sulfide and 1,1-bis(4-hydroxyphenyl)cyclohexane.

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

The heat-sensitive recording material of the present invention is used in various fields, but in particular, it takes advantage of the above-mentioned excellent color image stability,
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 heat-sensitive coloring layer containing a leuco dye and the color developer is provided on one side of the support, and a heat-sensitive coloring layer containing a leuco dye and the color developer is provided on the other side of the support.
A release mount may be provided via an adhesive layer, and in the case of a magnetic ticket, a magnetic recording layer containing a ferromagnetic material and a binder as main components may be provided in place of the release mount.

It is also possible to use the leuco dye and the color developer as a heat-sensitive transfer material provided on separate supports.

〔effect〕

Since the heat-sensitive recording material of the present invention uses at least one of the compounds represented by the above general formula as a color developer, it has higher sensitivity than conventional heat-sensitive recording materials, less fading of recorded images over time, and reliability. This is an improved version of

〔Example〕

The present invention will now be explained in more detail with reference to Examples.

Note that all parts and gourds below are based on weight.

Example 1 [Liquid A] 10% polyvinyl alcohol aqueous solution 10 parts water
80 parts [Liquid B] Calcium carbonate 15 parts Zinc stearate 5 parts 10% polyvinyl alcohol aqueous solution 30 parts Water
40 parts of each mixture with the above composition was mixed with a sand glider for 2~
[Liquid A] and [Liquid B] were prepared by pulverizing and dispersing for 4 hours.

Next, a heat-sensitive coloring layer coating solution was prepared by mixing and stirring so that the weight ratio of [Liquid A] and [Liquid B] was 1=3, and the coating solution was coated on commercially available high-quality paper so that the dry coating amount was 5 g/rrf. It was coated with a lab coating rod and dried. This coated paper was calendered to a smoothness of 700-1200 seconds to prepare a heat-sensitive recording material of the present invention.

Example 2 In Example 1, p-hydroxybenzoic acid (2-acryloyloxy) ethyl ester in [Liquid B] was added to 3°4
-dihydroxybenzoic acid (2-methacryloyloxy)
A heat-sensitive recording material of the present invention was prepared in the same manner as in Example 1 except that ethyl ester was used instead.

Example 3 In Example 1, 3-N-methyl-N- in [Liquid A]
Cyclohexylamino-6-methyl-7-anilinofluorane to 3-N-ethyl-N-isoamylamino-6-
Except that p-hydroxybenzoic acid (2-acryloyloxy) ethyl ester in [Liquid B] was replaced with 2,4-dihydroxybenzoic acid (2-acryloyloxy) ethyl ester instead of methyl-7-anilinofluorane. A heat-sensitive recording material of the present invention was prepared in the same manner as in Example 1.

Comparative Example 1 A comparative example was prepared in the same manner as in Example 1, except that p-hydroxybenzoic acid (2-acryloyloxy)ethyl ester in (Liquid B) was replaced with benzyl ρ-hydroxybenzoate. A thermosensitive recording material was created.

Comparative Example 2 A comparative heat-sensitive recording material was prepared in the same manner as in Example 1, except that P-hydroxybenzoic acid (2-acryloyloxy) ethyl ester in [Liquid B] was replaced with bisphenol A. Created.

The above heat-sensitive recording materials were tested for color development and humidity and heat storage stability. The results are shown in Table 1.
The test method was as follows.

(1) Printing tester made of color-forming electronic parts and equipped with a thin film head, head power 0.60V/dot, 1 line recording time 10
wrs/Q, scanning line density 8X7-. Printing was performed with a pulse width of 1.0 ms under the conditions of 7 dots/mm, and the print density was measured using a Macbeth densitometer RD-514 (filter vratten).
-106).

(2) Samples printed in the test of humidity and heat resistance (1) at 40℃, 90% R
After being left under H for 24 hours, the density of the image area was measured and evaluated.

Table 1 As is clear from Table 1, the heat-sensitive recording material of the present invention has higher sensitivity, better moist heat resistance, and improved reliability than the comparative example.

Claims (1)

[Claims] (1) A heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer, characterized in that the color developer is at least one of the compounds represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 represents a hydrogen atom or a methyl group, R_2 represents a lower alkylene group, and n represents an integer from 1 to 3.)