JPS63256487A - Thermal color forming recording material using fluoran compound - Google Patents

Abstract

PURPOSE:To augment the development of a color capable of absorbing electromagnetic waves ranging from a visible ray region to a near IR region, by using a fluoran compound having an amine residue at 3-position and a mono-substd. amino group or di-substd. amino group at 7-position as a color forming dye, and using a quinoid-type electron-acceptive compound as a color developer. CONSTITUTION:A quinoid-type electron acceptive compound is used, either singly or in combination, as a color developer, in a thermal recording material comprising a color forming dye based on a fluoran compound having an amine residue at 3-position and a mono-substd. or di-substd. amino group at 7-position and the color developer. When the fluoran compound is used with the quinoid- type compound as the color developer, a color is developed which shows strong absorption of electromagnetic waves ranging from a visible ray region to a near IR region. The quinoid-type compound absorbs the electromagnetic waves in only the visible ray region, so that it does not interfere with the use of a record reader utilizing the absorption of electromagnetic waves in a near IR region.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermosensitive color-forming recording material that utilizes color development that also absorbs in the near-infrared region of electromagnetic waves.

[Conventional technology]

Recently, new applications are being developed in connection with the development of both electronics and information management systems. One example is usage. At this time, there is a tendency for reading devices that use semiconductor radar to be frequently used to read the markings because they are inexpensive. However, this semiconductor laser has a wavelength of 650
Since it emits visible light and near-infrared rays of nm or more, the markings read by this device must absorb visible light and near-infrared rays in this wavelength range.

Heat-sensitive recording materials have conventionally been widely used for computer output, facsimiles, recording paper for recorders, tickets, passes, etc., but when using reading devices that use semiconductor lasers as described above, The type of heat-sensitive recording material used is also different from conventional ones.

[Problem to be solved by the invention]

Although such heat-sensitive recording materials include, for example, those using phthalide compounds, thiofluorane compounds, fluorene compounds, and fluoran compounds as color-forming dyes, as their uses expand and diversify, the above-mentioned There has also been a demand for diversification of heat-sensitive recording materials that absorb electromagnetic waves in the long wavelength range.

[Means for the invention to solve the problem]

Therefore, the present inventor investigated heat-sensitive recording materials using fluoran compounds, and found that fluoran compounds having an amine residue at the 3-position and a mono- or di-substituted amino group at the 7-position are quinoid-type compounds t- It was discovered that when used as a color developer, it can be used as a thermosensitive color-forming recording material that generates color that strongly absorbs electromagnetic waves from the visible region to the near-infrared region.

[Structure of the invention]

Therefore, the object of the present invention is to provide a heat-sensitive recording material comprising a color-forming dye of a fluoran compound having an amine residue at the 3-position and a mono- or di-substituted amino group at the 7-position and a color developer. It is an object of the present invention to provide a novel recording material that uses a quinoid type electron-accepting compound alone or in combination as an agent and has enhanced color development that absorbs electromagnetic waves from the visible region to the near-infrared region.

The fluoran compound used in the present invention having an amino residue at the 3-position and a mono-substituted amino group or a di-substituted amine group at the 7-position is usually colorless or light-colored, but develops a black or green color depending on a color developer. It is a sex dye. They are well-known compounds with the general formula % formula % where X represents a mono-substituted amino group or a di-substituted aino group, where the mono-substituted amino group is arylamine 7
or a benzylamino group, and the di-substituted amino group is a dialkylamino group, a dialkylamino group, a dibenzylamino group, an alkyl-arylamino group or an alkyl-benzylamino group, and the penzenylamino group in which they are present is The ring is a halogen atom, an alkyl group of 01 to C5, 0
1-C5 alkoxy group, nitro group, carbamoyl group,
The alkoxyl may be substituted with a nyl group or/and a halogenated alkyl group.

Phase and R2 are each independently an alkyl group of 01 to 018, an alkenyl group of C1 to 01B, a cycloalkyl group of 05 to C6, an aryl group or an alkoxy group, a phenyl group, a cycloalkyl group, a saturated heterocyclic group or an unsaturated group. Represents a C1-CS alkyl group substituted with a heterocyclic group.

R3, Ra and R5 each independently represent a hydrogen atom, a halogen atom, an 01-C8 alkyl group, an 01-C8 alkenyl group, an 01-C8 alkoxy group, a 7-enyl group, or an aralkyl group.

Furthermore, R1 and R2 may be combined with the nitrogen atom to which they are attached to form a pyrrolidino, piperidino, or morpholif group, and R4 and R5 may be combined with each other to form IIA. A naphthalene ring may also be formed.

However, when X is a di-substituted amino group, R5 is a hydrogen atom.

ff1B represents a benzene ring, a naphthalene ring, a pyridine ring, a quinoline ring, an inquinoline ring, a siacine ring, or a benzocyacine ring, and these rings are halogen atoms, 01-
It may be substituted with a C8 alkyl group or/and a nitro group.

R1, R2, R3, B4, R5, R1 and B2 and R4
and R5, the cycloalkyl group, phenyl group, aralkyl group, naphthyl group, heterocyclic group, and aryl group that are bonded or formed are monologen atoms, C1 to C5 alkyl groups, 01 to C5 alkoxy groups, carbamoyl groups, or / and alkoxylic? It may be substituted with a nyl group.

Of course, it goes without saying that the alkyl group, alkenyl group, and alkoxy group are not only linear, but may also have a branched chain.

As mentioned above, the fluoran compound represented by the general formula (1) is a well-known color-forming dye that develops a black or green color tone.

In particular, many compounds that develop a black color are known, and among them, the representative ones that are in practical use are 3-diethylamino-6-methyl-7-anilinofluorane, 3-non-n -butylamino-6-methyl-7-anilinofluorane, '3-N-cyclohexyl-N-methylamino-6-methyl-7-anilinofluorane, 3-N-n-propyl-
N-methylamino-6-methyl-7-anilinofluorane, 3-cy:S'F-ruami, t-b-chloro-
7-7 dilinofluorane, 3-N-inbutyl-N-ethylamino-6-methyl-
7-anilinofluorane, 3-N-isopentyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-7-
m-) Lifluorotetramethyl-anilinofluorane, 3-di-n-butylamino-7-(0-chloroanilino)fluorane, 3-N-ethyltoluidino-6-methyl-7-anilinofluorane, 3-piperidino -6-Methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-N-n-amyl-N-ethylamino-6-methyl-
7-anilinofluorane, 3-N-f'trahydrofurfuryl-N-methylamino-6-methyl-7-anilinofluorane, and the like.

In addition, there are relatively many compounds that develop a greenish color, such as 3-diethylamino-tudipenzol-aminofluorane, 3--/ethylamino-5-methyl-7-dipendylaminofluoran, and 3-N-isobutyl-N. -ethylamino-7-anilinofluorane, 3-pyrrolidino-7-dibenzolaminofluorane, and the like. The black coloring type and green coloring type fluoran compounds that can be used in the present invention are not limited to the fluoran compounds described above.

a Yl and Yl may be the same or different, and they represent an oxygen atom or/and a group represented by the formula =C (2, in which O
2 is a cyano group or a 7-substituted cargonyl group in a C1 to C5 alkoxy group.

A quinoid type electron-accepting compound is formed by a combination of Yl and Yl, in which both Yl and Yl are in the acid dimethane form,
There are three forms: the quinomethane form, where one is a rag atom and the other is -C12.

The bond in each of the above formulas is a hydrogen atom, an alkyl group, an alkoxy group, an aryoloxy group, or, for example, a chlorine atom,
Bromine atom, nitro group, cyano group, arylsulfonyl group, alkylcar-nyl group, aryloxycar-nyl group, alkyloxycar-nyl group, arylsulfonyl group, alkylsulfonyl group, arylsulfinyl group, alkylsulfinyl group, etc. ], and furthermore, adjacent bonds may be further bonded to form a new aryl ring. Of course, it may also have.

When the quinoid type electron-accepting compound is a quinone type, at least one of the groups bonded to the bond needs to be an electron-withdrawing group as described above.

Specific examples of the quinoid type electron-accepting compounds include 2,5-cycloo-1,4-benzoquinone, 2,
6-dichloro-1,4-benzoquinone, 2,3,5.6
-tetrachloro-1,4-benzoquinone (commonly called "chloranil"), 2,3,5,6-tetracyano-1,
4-benzoquinone, 2,3-dichlorot'! -5,6-
Dicyano-1,4-benzoquinone, 3.4.5.6-tetracyano-1,2-benzoquinone, 2.3-dichloro-1,4-naphthoquinone, 3.6-dipromo 2.5-
Jetoxyl is nyl-1,4-benzoquinone, 3.6
-cyphenylsulfonyl-2,5-jetoxycaryl-1,4-benzoquinone, 7.7.8.8-tetracyano-1,4-quinodimethane (3,6-bis(dicyanomethylene) -1,4-cyclo Hexadiene (commonly known as "tetracyanoquinodimethane"), 7,7,8.
8-tetrakis (methoxycaryl) -1,4-quinodimethane, ? ,9,10.10-tetracyano-1,
4-naphthoquinodimethane, 9.9,10.10-tetracyano-2,6-naphthoquinodimethane, 11,11,1
2゜12-tetracyano-9,10-anthraquinodimethane, 11,11.12.12-tetracyano-2,6
-Anthraquinodimethane, 10-(dicyanomethylene)
Anthrone, 10-bis(ethoxycaryl)methyleneantrone, 11.11-dicyano-12,12-
Examples include, but are not limited to, bis(ethoxycarnyl)-9,10-anthraquinodimethane.

In general, quinoid electron-accepting compounds exhibit a yellowish appearance. Therefore, in the case of the heat-sensitive recording paper manufactured in each example, the background portion exhibits a pale yellow color.

However, this pale yellow pigment absorbs electromagnetic waves only in the visible region, and there is no problem with a kama-reading device that utilizes electromagnetic wave absorption in the near-infrared region.

In the heat-sensitive color-forming recording material of the present invention in which a fluoran compound having an amonyl residue at the 3-position and a mono-substituted amino group or a di-substituted amino group at the 7-position is combined with a quinoi P-type electron-accepting compound as a color developer. The proportions of these compounds are determined in consideration of the electron-accepting ability of the quinoid-type electron-accepting compound, and cannot be generally determined. However, it is usually preferable to use 0.5 to 5 parts by weight of the latter to 1 part by weight of the former.

In this case, the quinoid type electron-accepting compound as a color developer may be used alone or in combination. Further, in order to adjust electromagnetic wave absorption in the visible region, it may be used in combination with other conventionally used color developers. For example, such color developers include bisphenol compounds typified by bisphenol A'), hydroxybenzoic acid esters typified by benzyl 4-hydroxybenzoate, and 4-hydroxy-41-isopropoxydi7 Le, X, Le*
7 t Representative j: -SulfyP-roxyphenylsulfones, zinc thiocyanate complexes typified by complex salts of zinc thiocyanate and antihyrinthate, and inorganic acidic substances typified by activated clay.

Furthermore, color developers effective in absorbing electromagnetic waves in the near-infrared region, such as organic sulogen compounds that generate halogen radicals such as tribromomethylphenylsulfone, 4
- It is also possible to use it in combination with nitrobenzoic acid derivatives represented by zinc nitrobenzoate and their metals.

It goes without saying that the fluoran compound represented by the general formula (1) can be used alone, but it is also possible to use a mixture of these compounds. These fluoran compounds exhibit a black or green color depending on a conventional color developer. In the present invention, these fluoran compounds and a conventional color developer exhibit color development of red, blue, etc. It is also possible to use a dye in combination, and it is also possible to use a mixture with a color-forming dye that absorbs near-infrared light when coloring.

The method for producing thermal recording paper using the fluoran compound represented by the general formula (1) and the quinoid type electron-accepting compound is the same as that for conventional color-forming dyes, and for example, Japanese Patent Publication No. 39-27579 , Special Publication No. 43-4160,
Special Publication No. 45-14039 or Japanese Patent Publication No. 59-708
It can be manufactured according to the method described in Publication No. 7 and the like.

That is, for example, a dispersion in which fine particles of the fluoran compound of general formula (1) or a mixture thereof with other color-forming dyes and fine particles of an acidic color developer are neutralized and dispersed in an aqueous solution of a water-soluble binder is applied to paper. By drying, a heat-sensitive recording paper with excellent color development can be obtained. When a sensitizer is added to the dispersion, a heat-sensitive recording paper with extremely high sensitivity can be obtained. The dispersion may further contain fillers, dispersants, color image stabilizing agents, antioxidants, desensitizers, antiblocking agents, antifoaming agents, light stabilizers, fluorescent whitening agents, etc. Can be done. Furthermore, it is also possible to color the thermosensitive recording paper by adding dyes or pigments to this dispersion.

Above is a detailed explanation of its use in thermal recording paper.
The method of use of the present invention is not limited to this, and for example, thermal transfer recording, current recording, and electrostatic recording isobaric can also be applied.

The recording paper produced according to these methods can be provided with a protective layer on its surface if necessary, and can also be provided with an adhesive layer on its back side to make it convenient to use as a label.

In addition, recording materials manufactured according to these methods are used, for example, in copying books, documents, etc., electronic computers, facsimile machines, bar codes, ticket vending machines, labels, car P, etc., and are also used for high-density input information, e.g. Since the recorded information cannot be seen with the naked eye, it can be used in a wide range of applications such as prevention of forgery, prevention of duplication, unlocking devices, and radar disks.

Here, an interesting use example utilizing the coloring characteristics of the thermosensitive color-forming recording material of the present invention will be given.

For example, in a thermal recording paper manufactured using a mixture of both bisphenol A and tetracyanoquinodimethane as a t-color developer, color is developed at a low temperature (e.g. 120°C) in some areas, and at a high temperature (e.g. If the color is developed at a temperature of 210 degrees Celsius), even though these locations appear to be almost the same color, only the locations where the color develops due to the high temperature will be sensitive to a device that can read information using infrared rays.

Alternatively, if a part of the thermosensitive recording paper is heated at a low temperature to develop a color (for example, black), then heated at a higher temperature to develop a color (the order of heating may be reversed), the color will appear uniform to the naked eye. Information that can be read by a device capable of reading information using infrared rays can be recorded in the black part.

The wavelength range of the electromagnetic waves absorbed by the above-mentioned fluoran compounds using conventionally used color developers (so-called acidic substances, such as bisphenol A5 clay) is limited to the visible range.

〔Effect of the invention〕

The thermosensitive color-forming recording material of the present invention, which is a combination of the above-mentioned fluoran compound and quinoid type electron-accepting compound, has a wavelength range of electromagnetic waves absorbed by the coloring extended from the visible region to the near-infrared region. Furthermore, an interesting characteristic of color development is that as the heating temperature for color development increases, the wavelength range of electromagnetic waves absorbed by the color development expands to longer wavelengths.

Such changes in the electromagnetic wave absorption range depending on the coloring temperature are not observed in the combination of the fluoran compound and the so-called acidic color developer used conventionally. This will be explained in detail below. , FIG. 1 and FIG. 2 are reflection curves showing the coloring characteristics of the thermosensitive color-forming recording material of the present invention. Figure 1 shows the thermosensitive recording paper (1) of Example 1 (a combination of 3-N-n-propyl-N-methylamino-6-methyl-7-anilinofluorane, tetracyanoquinodimethane, and 0ffl). 210℃
(curve figure), reflection curves of colored areas heated and colored at temperatures of 230°C (curve B) and 250°C (curve C) and thermal recording paper (10) of Comparative Example 1 (with the same fluoran compound as Example 1). combination with bisphenol-A) 1-230
250° C. (curve D) and 250° C. (curve E). combination of amino-6-methyl-7-anilinofluorane and tetracyanoquinodimethane)'j-210°C (curve F
), 230°C (curve G) and 250°C (curve H). combination) 'i 230℃ (curved work)
and 2 reflection curves obtained by heating and coloring at a temperature of 250° C. (curve J).

That is, in FIGS. 1 and 2, when the fluoran compound represented by the general formula (1) is used as a quinoid type electron acceptor t-color developer, it is not possible to develop the color using the generally used acidic base. This is clearly different from the case of using colorants, in that the absorption wavelength range of electromagnetic waves reaches the near-infrared region, and by increasing the coloring temperature, the absorption wavelength range is extended to longer wavelengths. Characteristics that were not yet known have been revealed.

Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Dye dispersion difluoran clay 11. ! M15
PVA aqueous solution 41.4M water
4αOf color developer dispersion tetracyanoquinodimethane 1α5t clay &O2151PV
A water soluble 11. <1. st water
4αO2 Glass beads (diameter 1 to 1.5 m) 1
Put it in a polyethylene bottle with 50 f, tightly stopper it, and turn it into a red
The mixture was ground for several hours in a paint conditioner manufactured by Devi1 to obtain a dye dispersion and a color developer dispersion.

Next, the dye dispersion liquid and the color developer dispersion liquid were mixed in a weight ratio of 1:2 to prepare a coating liquid t-g.

This coating liquid is applied to white base paper, dried, and heat-sensitive recording paper 11
)t-manufactured.

Regarding the thermal recording paper (1), use a drying tester (manufactured by Kishino Kagaku Kikai Co., Ltd.) f: 210°C, 230°C and 2
All six colors developed by heating both sides at a temperature of 50° C. were black. Reflection curves (wavelengths 400 to 1200n) of the colored parts of this thermal recording paper at various temperatures
m) was measured using a spectrophotometer (Hitachi Seisaku Shinten, Model 0-3400 and the attached integrating sphere). These reflection curves are shown in FIG.

Example 2 3-N-n-propyl added to the dye dispersion of Example 1
3-di-n-butylamino-6-methyl- instead of N-methylamino-6-methyl-7-anilinofluorane
Using 7-anilinofluorane, otherwise Example 1
Thermal recording paper +II) was produced in exactly the same manner as described above. Color was developed in the same manner as in Example 1, and the reflection curve of the colored area was measured, and is shown in FIG. Note that this color development was black.

Comparative Example 1 Example 10 A thermosensitive recording paper (Dt-manufactured) was prepared in the same manner as in Example 1 except that bisphenol A' was used in place of tetracyanoquinodimethane in the color developer dispersion. The reflection curve was measured for each sample and is shown in Figure 1 together with the results of Example 1.The color developed was black.

Comparative Example 2 A bisphenol compound was used in place of tetracyanoquinodimethane in the color developer dispersion used in Example 2, and in the same manner as in Example 2 except for that, the thermal recording paper (Incorporated) was prepared.
was manufactured. The reflection curve of the colored area was measured and is shown in FIG. 2 together with the results of Example 2. Note that this color development was black.

Example 3 The dye dispersion of Example 1, the dye dispersion of Example 2, and the following black color-forming fluoran compound 3-N-hexyl-N-
Methylamino-6-methyl-7-anilinofluorane 3-N-isobutyl-N-ethylamino-6-methyl-
7-anilinofluorane 3-N-n-amyl-N-ethylamino-6-methyl-
7-anilinofluorane A dye dispersion prepared using 3-di-n-butylamino-7-(0-lytetraanilino)fluoran in the same manner as in Example 1 was used, and the dye dispersion of Example 1 was prepared. In place of tetracyanoquinodimethane in the coloring agent dispersion, chloranil was used. The colored parts are exposed to electromagnetic waves in the near-infrared region (700 nm,
780℃m, 830℃m, 900℃m and 10100
The reflectance at 0n was measured using a spectrophotometer (same as above) and the results are shown in Table 1. Note that all of these colors were black.

Example 4 3-N-n-propyl- in the dye dispersion of Example 1
In place of N-methylamino-6-methyl-7-anilite fluorane, use the following green coloring fluorane compound.
Thermal recording paper and X[I were produced. Color was developed in the same manner as in Example 3, and the reflectance of the colored area was measured, and the results are shown in Table 8g1 along with the results of Example 3. Note that these colors were greenish black.

Example 5 3,6-dipromo2,5-diethoxycargenylbenzoquinone Kl was used instead of tetracyanoquinodimethane in the color developer dispersion of Example 1, and the rest was Example 1.
Thermal recording paper XH1 was produced in exactly the same manner as described above. Color was developed in the same manner as in Example 1, and the reflectance (same as in Example 3) of the colored portion was measured, and the results are shown in Table 1 together with the results of Examples 3 and 4. Note that this color development was black.

1st surface reflectance (Aya 6) Recording paper temperature (℃) 700 780 830 90
0 11000nm
nm nm21016.94&459.1
6a57a4(■250 1(L81&02A0 27
．． 1 5C1,521012,024,031,54C
L45(LO(2501(L314921.5245
32.2 actual 210 1 & 3 51.4 6LO72-212
Stop 250 1 (Ll 2α2 27.0 3
&23&9210 14.0 34.9 4&0 55
．． 8 64.6 cases ” 250 1 (L2
19.3 25.8 3 (153 & 43 210
14046.55 & 765,4 69.5 (DO25
011,221,127,132,637,82102
L1 52.4 6L3 7α77Z2(x)250
1a1 35741.5 51.8 62.5210
21.9 64.7 74.4 8α0 82.8 real
α' 250 14.8 3&5 45.7
545 6a1 example 2101α1 36.4 61,3
77.3 194 (XID250 9.3 2&
441057.2 6 & 6 210 1
6.2 44.9 55.0 62.5 6a19,
l■1 In Table 1, the smaller the reflectance value, the greater the electromagnetic wave absorption.

That is, the thermosensitive color-forming recording material of the present invention produces color by strongly absorbing electromagnetic waves in the near-infrared region.

[Brief explanation of drawings]

FIGS. 1 and 2 show the reflection curves of the colored portions of each heat-sensitive recording paper, which are colored by varying the heating temperature. In Figure 1, curves A, B and C are thermal recording paper (1
) at 210°C, 230°C and 250°C, curves and E are thermal recording paper (IID) heated and colored at 230°C and 250°C. In Figure 2, curves F%G and B are thermal recording paper Paper (I
11 is heated at 210°C, 230°C and 250°C, and Curved and J are thermal recording paper manufactured by Co., Ltd., heated and colored at 230°C and 250°C.

Claims (1)

[Claims] A thermosensitive color-forming recording material using a fluoran compound having an amine residue at the 3-position and a mono- or di-substituted amino group at the 7-position as a color-forming dye, and a quinoid-type electron-accepting compound as a color developer.