JPH03261590A - Thermal recording material - Google Patents

Abstract

PURPOSE:To prevent background fog and to keep a sufficient PCS value even when a thermal recording material is exposed to high temp. and high humidity by adding a specific graft copolymer to the recording layer of the thermal recording material using a specific basic dye. CONSTITUTION:At least one kind of a compound represented by formulae [I] - [IV] (wherein R1 - R33 are respectively a specific atom, a specific group or a specific ring, a, b, c and d are respectively a carbon atom, X is a halogen atom and l, m, n and k are respectively 0 or an integer of 1 - 4) is added to a recording layer as a colorless or light-colored basic dye and a graft copolymer consisting of 20 - 90wt.% of an alkali salt of a styrene/(meth)acrylic acid copoly mer [styrene 60 - 80wt.%/(meth)acrylic acid 20 - 40wt.%] and 10 - 80wt.% of at least one kind of a monomer selected from an acrylonitrile monomer, an acrylic ester monomer and an acrylic acid monomer is added thereto.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a thermal recording material having excellent characteristics for optical character (or mark) reading devices having a reading wavelength range in the infrared region. be.

``Prior Art'' Conventionally, thermosensitive recording materials have been used that record information transmitted through the medium of thermal energy by utilizing a color reaction between a colorless or light-colored basic dye and an organic or inorganic electron-accepting substance. Are known.

In recent years, along with the streamlining of administrative processes, the number of cases in which recorded images on recording media are read and processed using optical character reading devices (including mark reading) has increased significantly. Character reading devices are increasingly being used.

For example, in the distribution industry, POS systems are attracting attention as a powerful tool in order to quickly respond to consumer needs, and price tags with OCR characters, barcodes, etc. are processed by computer at the same time as cash register payment. Although efforts are being made to improve business efficiency, the reader uses a small, inexpensive device with a reading wavelength in the infrared region.

However, the recorded images (black colored image, blue colored image, red colored image, green colored image, etc.) obtained with general thermosensitive recording materials are in the visible region (
For optical character readers with a reading wavelength range of 400 to 700 nm), it is possible to read as a read color, but for optical character reading equipment with a reading wavelength range of 700 to 900 nm, it is possible to read as a read color. It could not be applied because it all functions as a dropout color regardless of the color tone.

For this reason, the development of basic dyes suitable for optical character reading devices that utilize near-infrared light is underway; for example, 2
Phthalide derivatives having two vinyl groups (Japanese Patent Publication No. 5B-5
940, etc.) and phthalide derivatives with a fluorene skeleton (
JP-A No. 59-199757, etc.) have been proposed.

However, thermal recording materials using these basic dyes are more prone to background fogging than thermal recording materials using ordinary basic dyes, and in particular, the difference between the printed area and the background area is affected by temperature and humidity. optical contrast (POS value)
This has the disadvantage that optical character reading devices tend to have a tendency to reduce their readability, and therefore there is a strong demand for improvements in these areas.

"Problems to be Solved by the Invention" In view of the current situation, the present inventors have conducted extensive studies in order to obtain a heat-sensitive recording material that does not have the above-mentioned drawbacks. As a result, the inventors discovered that such defects can be significantly improved by incorporating a specific graft copolymer into the recording layer, leading to the completion of the present invention.

"Means for Solving the Problems" The present invention provides a heat-sensitive recording layer on a support that utilizes a coloring reaction between a colorless or light-colored basic dye and a coloring agent that can be colored by contacting the dye. In the heat-sensitive recording material, the recording layer contains at least one of the compounds represented by formulas (1) to [■] below as a basic dye, and (a) styrene/(meth)acrylic. Acid copolymer [styrene 60-80% by weight/(meth)acrylic 120-40%
20 to 90% by weight of an alkali salt of 20% to 90% by weight of an alkali salt of This is a heat-sensitive recording material characterized by containing a graft copolymer with 10 to 80% by weight of a monomer.

Rs R [In the formula, R1-R1 are each a hydrogen atom; c, ~c8 alkyl group; C1-C1 cycloalkyl group; C4-C
, alkoxyalkyl group; c, ~C9 unsaturated alkyl group; tetrahydrofurfuryl group: tetrahydropyran-2-methyl group; Good aralkyl group; halogen atom, C, -C, alkyl group, aryl group optionally substituted with cl-C1 alkoxyl group; halogen atom, C1-C4 alkyl group, 01
- indicates a C2-C3 alkyl group having a phenoxy group which may be substituted with a C4 alkoxyl group, and R3 and R2, R3 and R, R5 and Rh form a heterocycle with each other or with an adjacent benzene ring You can also. [In the formula, R1-R11k are each a hydrogen atom; a halogen atom; a nitro group; an optionally substituted C3 to C7 saturated or unsaturated alkyl group; an optionally substituted C2 to C8 cycloalkyl group; an optionally substituted C1-C1 alkoxyl group; an optionally substituted 02-C4 acyloxy group; an optionally substituted C6-Cro aryl group; an optionally substituted C1-C1□ aralkyl group; optionally substituted phenoxy group; optionally substituted C1-C4 thioalkoquine saturated alkyl group; optionally substituted C3-
C8 cycloalkyl group; optionally substituted C6-C,
.

Aryl group; optionally substituted C1-C1□ aralkyl group; tetrahydrofurfuryl group; optionally substituted C2-Cb acyl group, which forms a heterocycle with each other or with adjacent benzene rings You can also. ) and R1? represents a hydrogen atom; a C8-C4 alkyl group. a, b, c, and d each represent a carbon atom, but one or two of them may be nitrogen atoms. A hydrogen atom; a halogen atom: a CI-C4 alkyl group; a C3-C4 alkoxyl group; an optionally substituted amino group; a nitro group may be bonded to the carbon atom as a substituent, and a-b, b- c.
Alternatively, the c-d bond may form another aromatic ring. ] indicates an integer. Further, the broken line indicates that a naphthalene ring may be formed with an adjacent benzene ring. ] [In the formula, RtO
is a halogen atom; a C8-C3 alkyl group icI'-"
C4 alkoxyl group; cyclohexyl group; phenyl group; optionally substituted amino group; R□ and R13 each represent a hydrogen atom; C1 to C4 alkyl group; R1! ,
Rta is each a halogen atom; a C+ to C4 alkyl group;
Indicates a C1-C4 alkoxyl group. R13 and R26 are each a hydrogen atom; an optionally substituted C1-C saturated or unsaturated alkyl group; an optionally substituted C2-Cs cycloalkyl group; an optionally substituted C6-C1° aryl group : C9 to C+z aralkyl group which may be substituted; Tetrahydrofurfuryl group; C2 to C8 acyl group;
Indicates a sulfonyl group. X represents a halogen atom, ISm
, n are each 0 or 1 to 4F? 33 [In the formula, R2 and ~R3° each represent an alkyl group of 01 to C8; a cycloalkyl group of C3 to C8; an alkoxyalkyl group of C3 to C8; an unsaturated alkyl group of C3 to C1. Furthermore, RZ7 and R21l, and R29 and R3° may form a heterocycle with each other or with an adjacent benzene ring.

R1 and R3□ are each hydrogen atom; C1 to C4 alkyl group; halogen atom, C1 to C4 alkyl group, 01 to C4
represents a phenyl group which may be substituted with an alkoxyl group or a substituted or unsubstituted amino group, and R33 represents an optionally substituted C8-C4 alkyl group; represents an optionally substituted phenyl group. As mentioned above, the invention has an important feature in that a specific graft copolymer is contained in the recording layer of a heat-sensitive recording material using a specific basic dye. By using this, background fogging is prevented, and the decrease in optical contrast between the printed area and the background area due to the influence of temperature and humidity is greatly improved, and the PCS value is sufficient even when exposed to high temperature or high temperature conditions. The present invention provides a heat-sensitive recording medium that can maintain the following properties.

The copolymer used in the present invention is (al styrene/(meth)acrylic acid copolymer [60-80% by weight of styrene and (meth)acrylic #120-4
0% by weight of an alkali salt of the copolymer] and 0) at least one selected from acrylamide monomers, acrylonitrile monomers, acrylamide monomers, and acrylic acid monomers. It is a product obtained by graft copolymerization of 10 to 80% by weight of monomers.

The above-mentioned graft copolymer can be prepared, for example, by the following method.

First, predetermined amounts of styrene and acrylic acid (or methacrylic acid) are polymerized by a bulk polymerization method using a radical polymerization initiator and, if necessary, a chain transfer agent.Then, the obtained styrene/acrylic acid copolymer is After adding an alkali to the polymer and neutralizing it to prepare an aqueous solution of styrene/acrylic acid copolymer, a predetermined amount of component monomer and a radical polymerization initiator are added and copolymerized. The desired graft copolymer is obtained.

The molecular weight of the styrene/(meth)acrylic acid copolymer is preferably about 30,000 or more.

Examples of the alkali used to neutralize the styrene/acrylic acid copolymer include sodium hydroxide, potassium hydroxide, alkylamine, alkanolamine, morpholine, and ammonia.

Further, specific examples of the monomers of the component (base) include acrylamide, methacrylamide, N-alkylolacrylamide, N-(alkoxymethyl)acrylamide, diacetone acrylamide, N-(alkylaminoalkyl)acrylamide, N-(alkyl Sulfonic acid) acrylamide monomers such as acrylamide, acrylonitrile monomers such as methacrylonitrile, methyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate,
Examples include acrylic ester monomers such as dimethylaminoethyl methacrylate, tetrahydrofurfuryl methacrylate, and methoxyethyl methacrylate, and acrylic acid monomers such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid.

As described above, in the present invention, the weight composition ratio of styrene and acrylic acid (or methacrylic acid) is 60 to 80:20 to 40.
20 to 90% by weight of an alkali salt of a styrene/(meth)acrylic acid copolymer selected from acrylamide monomers, acrylonitrile monomers, acrylic ester monomers, and acrylic acid monomers A graft copolymer comprising 10 to 80% by weight of at least one monomer is used.

Incidentally, if the proportion of styrene in the alkali salt of a styrene/(meth)acrylic acid copolymer is less than 60% by weight, it tends to cause fogging on the skin, and if it exceeds 80% by weight, the alkali salt of the copolymer becomes watery. On the other hand, in graft copolymers, styrene and
The ratio of alkali salt of (meth)acrylic acid copolymer is 20
If it is less than 90% by weight, the viscosity of the graft copolymer will increase, making it difficult to prepare a coating solution for a heat-sensitive recording layer, and if it exceeds 90% by weight, only a heat-sensitive recording material with poor recording sensitivity will be obtained.

Therefore, in the present invention, a graft copolymer having a specific ratio as described above is used.

In the thermal recording body of the present invention, the general formula CI) ~ (mV)
A basic dye represented by the following is used, and specific examples of such basic dyes include the following.

-(I) 3-dimethylamino-6-[N-ethyl-N-(2-ethoxyethyl)aminocofluorene-9-spiro-3'
-(6'-dimethylamino)phthalide, 3-dimethylamino-6-[N-ethyl N-(2-methoxyethyl)aminocofluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3 -di-n-butylamino-6-
[N-Methyl-N-(2-methoxyethyl)aminocofluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3-pyrrolidino-6-[N-ethyl-N-(
2-ethoxyethyl)aminocofluorene-9-spiro-3'-(6'-pyrrolidino)phthalide, 3-(N-methyl-N-cyclohexylamino)-6-(N-ethyl-N-(2- ethoxyethyl)aminocofluorene-9
-spiro-3'-(6'-dimethylamino)phthalide,
3-diethylamino-6-(N-methyl-N-allylamino)fluorene-9-spiro-3'-(6'-dimethylaξ))phthalide, 3-dimethylamino-6-(diallylamino)fluorene-9-spiro -3'-(6'-
dimethylamino)phthalide, 3-di-n-butylamino-6-(N-methyl-N-allylamino)fluorene-
9-spiro-3'-(6'-dimethylamino)phthalide, 3-pyrrolidino-6-(N-ethyl-N-2-butenylamino)fluorene-9-spiro-3'(6'-dimethylamino)phthalide, 3-(N-methyl-N-cyclohexylamino)-6-(N-ethyl-N-propargylamino)fluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3-dimethylamino-6-( N-
Methyl N-tetrahydrofurfurylamino)fluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3-diethylamino-6-(N-ethyl-N-tetrahydrofurfurylamino)fluorene-9-spiro-
3'-(6'-dimethylamino)phthalide, 3-diethylamino-6-(N-methyl-N-tetrahydrofurfurylamino)fluorene-9-spiro-3'-(6'-dimethylamino>phthalide, -n-propylamino 6-(N-methyl-N-tetrahydrofurfurylamino)fluorene-9-spiro-3'-(6'dimethylamino)phthalide, 3-morpholino 6-(N-butyl-N-
Tetrahydrofurfuryl a)) Fluorene-9-spiro-3'-<6'pyrrolidino)phthalide, 3-(N-ethyl-N-cyclopentylamino)-6-(N-ethyl N-tetrahydrobilane-2-methyla )) Fluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3-dimethylamino-6-[N-ethyl-N-(
2-phenylethyl)aminocofluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3-diethylamino-6-[N-methyl~N-(1-phenylethyl)aminocofluorene-9- spiro-3'-(6'
-dimethylamino)phthalide, 3-diethylamino-6
-(N-ethyl-N-p-chlorobenzylamino)fluorene-9-spiro-3'-(6'-dimethylamino)
Phthalide, 3-pyrrolidino-6-(N-n-butyl-N
-(2-phenylethyl)aminocofluorene-9-spiro-3'-(6'-morpholino)phthalide, 3-(N
-n-octyl-N-methylamino)-6-(N-methyl-N-(1-phenylethyl)aminocofluorene 9
-spiro-3'-(6'-dimethylamino)phthalide,
3-dimethylamino-6-[N-methylN-(2-phenoxyethyl)aminocofluorene-9-spiro-3'
-(6'-dimethylamino)phthalide, 3-diethylamino-6-(N-methyl-N-(2-phenoxyethyl)aminocofluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3 -di-n-butylamino 6
-(N-ethyl-N-(2-(p-methoxyphenoxy)ethylcoamino)fluorene-9 spiro-3'-(6
'-diethylamino〉phthalide, 3-pyrrolidino-6-
(N-n-butyl-N-(3-(p-chlorophenoxy)propylcoamino)fluorene-9-spiro-3'-
(6'pyrrolidino)phthalide, 3-(N-methyl-N-
cyclohexylamino)-6-(N-methyl-N(2-
(p-methylphenoxy)ethyl)amino)fluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3-diethylamino6-dimethylaminofluorene-9-spiro-3'-(6'- dimethylamino)phthalide, 3,6-bis(diethylamino)fluorene-9-
Spiro-3'-(6'-dimethylamino)phthalide, 3
Di-n-butylamino-6-dimethylaminofluorene-9-spiro-3''(6'-dimethylamino>phthalide, 3-di-n-butylamino-6-ethylaminofluorene-9-spiro- 3'-(6'-dimethylamino)
Phthalide, 3.6bis(dimethylamino)fluorene-
9-spiro-3'-(6'-diethylamino)phthalide, 3-diethylamino-6-dimethylaminofluorene-9-spiro-3'-(6'-diethylamino)phthalide, 3-di-n-butylamino -6-dimethylaminofluorene-9-spiro-3'-(6'diethylamino)
Phthalide, 3,6-bis(diethylamino)fluorene-9-spiro-3'(6'-diethylamino)phthalide, 3-di-n-butylamino-6-ethylaminofluorene-9-spiro-3'- (6'-diethylamino)
Phthalide, 3,6-bis(dimethylamino)fluorene-9-spiro-3'-(6'-di-n-butylamino)
Phthalide, 3-diethylamino-6-dimethylaminofluorene-9-spiro-3'-(6'-di-n-butylamino)phthalide, 3-dimethylamino-6-methylaminofluorene-9-spiro-3'- (6'-dimethylamino)phthalide, 3-dimethylamino-6-sibenzylaminofluorene-9-spiro-3'-(6'dimethylamino)phthalide, 3-pyrrolidino-6-dimethylaminofluorene-9-spiro -3'(6'-dimethylamino)phthalide, 3-piperidino-6-dimethylaminofluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3-dimethylamino-6-<N-methyl-
N-cyclohexylamino)fluorene-9-spiro-
3'-(6'-dimethylamino)phthalide, 3゜6-bis(dimethylamino)fluorene-9-spiro-3'-
(6'-dimethylamino)phthalide, etc.

- Produced by [■] ・3.3-bis[1,1-bis(4-dimethylaminophenyl)ethylene-2-yl)-4,5゜6.7-titrachlorophthalide, 3,3- Bis[1,1-bis(4-diethylaminophenyl>ethylene-2-yl)-4,5
, 6,7-titrachlorophthalide, 3,3-bis[1,
1-bis(2-methyl-4-diethylaminophenyl)
ethylene-2-yl) -4,5,6,7-titrachlorophthalide, 3.3-bis(1,l-bis(2-methoxy-4-diethylaminophenyl)ethylene 2-yl)
-4,5,6,7-titrachlorophthalide, 3,3-bis[1,1-bis(4-dimethylaminophenyl-1-
Propen-2-il2 4.5.6. Fuchtrachlorophthalide, 3゜3-bis[1,1-bis(4-dimethylaminophenyl)ethylene-2-yl]-5-pyrrolidinophthalide, 3,3-bis[l,1-bis( 4-dimethylaminophenyl)ethylene-2-yl]-6-pyrrolidinophthalide, 3,3-bis[1,l-bis(4-dimethylaminophenyl)ethylene-2-yl)-5,6-
Dichlorophthalide, 3゜3-bis[l, 1-bis(4-
dimethylaminophenyl)ethylene-2-yl]phthalide, 3.3-bis[l, 1-bis(4-dimethylaminophenyl)ethylene-2-yl]-5-dimethylaminophthalide, 3.3-bis[l, 1,1-bis(4-dimethylaminophenyl)ethylene-2-yl]-6-dimethylaminophthalide, 3,3-bis[1,14''s(4-dimethylaminophenyl)ethylene-2-yl ]-5-nitrophthalide, 3゜3-bis[1,1-bis(4-dimethylaminophenyl)ethylene-2-yl]-6-nitrophthalide, 3.3-bis[1,1-bis(4-diethylamino phenyl)ethylene-2-yl]-5ethoxyphthalide, 3.3-bis[1,1-bis(4-diethylaminophenyl)ethylene-2-yl]-6-nitoxyphthalide, 3.3-bis[1, 1-bis(4-dimethylaminophenyl)ethylene-2-yl]-5-methylphthalide, 3゜3-bis[1,elbis(4-dimethylaminophenyl)ethylene-2-ylgo6-methylphthalide, 3,3- Bis[1,l-bis-(4-N ethyl-N
-benzylaminophenyl)ethylene 2-yl)-4,
5,6,7-titrachlorophthalide, 3,3-bis[1
,1-bis-(4-N-methyl-N-p-t-lylagonophenyl)ethylene-2-yl)-4,5,6,7-
Titrachlorophthalide, 3,3-bis[1,■-bis(
4-dimethylagonophenyl)ethylene-2-yl]-
5,6-penzophthalide, 3,3-bis(1゜1-bis(4-dimethylaminophenyl)ethylene-2-yl)
-4-Azaphthalide, 3,3-bis[1,1-bis(4
-dimethylaminophenyl)ethylene-2-yl]-5
-Azaphthalide, 3゜3-bis[1,1-bis(4-dimethylaminophenyl)ethylene-2-yl]-6-azaphthalide, 3.3-bis[1,1-bis(4-dimethylaminophenyl) Ethylene-2-yl]-7-azaphthalide, 3,3-bisC1,1-bis(4-dimethylaminophenyl)ethylene-2-yl]4,7-diazaphthalide, 3.3-bis[1゜1- Bis(4-dimethylaminophenyl)ethylene-2-yl)-5,6-benzo-4,7-diazaphthalide, 3,3-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2- Iltuphthalide, 3,3-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl)-4,5°6.7-
Titrachlorophthalide, 3,3-bis[1,1-bis(
4-pyrrolidinophenyl)ethylene-2-yl2-5-
Nitrophthalide, 3,3-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl)-6-nitrophthalide, 3゜3-bis(1,I-bis(4-pyrrolidinophenyl)ethylene) -2-yl2-5-ethoxyphthalide, 3,3-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl)-6-nitrophthalide,
3.3-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl-5-methylphthalide, 3.3
-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2-ylgo-6-methylphthalide, 3,3-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2
-yl]-5-pyrrolidinophthalide, 3,3-bis(1
,1-bis(4-pyrrolidinophenyl)ethylene-2-
Il2-6-virolidinophthalide, 3゜3-bis[1,
1-bis(4-pyrrolidinophenyl>ethylene-2-yl)-5,6-dichlorophthalide, 3,3-bis[1,
1-bis(4-piperidinophenyl)ethylene-2-yl]phthalide, 3,3-bis[1,1-bis(4-piperidinophenyl)ethylene-2-yl]-5-dimethylaminophthalide 3,3-bis[1,1-bis(4-piperidinophenyl)ethylene-2-yl]-6-dimethylaminophthalide, 3,3-bis[1゜l-bis(4-
piperidinophenyl)ethylene 2-yl)-4,5,6
, 7-titrachlorophthalide, 3.3-bis[1,1-
Bis(4-morpholinophenyl>ethylene-2-yl)
-4,5゜6.7-titrachlorophthalide, 3,3-bis[1,1-bis(4-hexamethyleneiminophenyl)ethylene-2-yl)-4,5,6,7-titrachloro Phthalide, 3,3-bis[1,1-bis(2-methyl-4-pyrrolidinophenyl)ethylene-2-yl)-4
, 5,6,7-titrachlorophthalide, 3,3-bis[
1,1-bis(2-methoxy-4-pyrrolidinophenyl)ethylene-2-yl)-4,5,6,7-titrachlorophthalide, 3,3-bis[l, 1-bis(4- pyrrolidinophenyl)-1-propen-2-yl)-4゜5.
6.7-Titrachlorophthalide, 3.3-bis(1,1
-bis(l-methyl-1,2,3,4tetrahydroquinolin-5-yl)ethylene-2-yl)-4,5,6,7
-titrachlorophthalide, 3,3-bis[1,1-bis(julolidin-9-yl)ethylene-2-yl)-4
, 5゜6.7-titrachlorophthalide, 3.3-bis[
1,1-bis(4-pyrrolidinophenyl)ethylene-2
-yl)-5,6-dichloro-4,7-dibromophthalide, 3,3-bis[1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl]4,7-dichloro5,6
-dipromofuclide, 3,3-bis[1,1-bis(4
-pyrrolidinophenyl〉ethylene-2-yl]-5-chloro-4゜6.7-dribromophthalide, 3.3-bis[1゜1-bis(4-pyrrolidinophenyl)ethylene-
2-yl]-6-chloro-4,5,7-)dibromophthalide, 3,3-bis(1-(4-ethylphenyl)-1
-(4-dimethylaminophenyl)ethylene-2-yl)-4,5,6,7-titrachlorophthalide, 3,3-
Bis(1-(4-methylphenyl)-1-(4-pyrrolidinophenyl)ethylene-2-yl)-4,5,6,7
-Titrachlorophthalide, 3,3-bis[1-phenyl 1-(4-dibenzylaminophenyl)ethylene 2-yl)-4,5,6,7-Titrachlorophthalide, 3.3
-bis[1,1-bis(4-ethoxyphenyl)ethylene-2-yl)-4,5゜6.7-titrabromophthalide, 3,3-bis[1-(4-ethoxyphenyl)-1
-(4-methoxyphenyl)ethylene-2-yl)-4
, 5゜6.7-titrachlorophthalide, 3,3-bis[
1-(4-cyclohexylphenyl)-1-(4-pyrrolidinophenyl)ethylene-2-yl]4.5,6.7
-titrachlorophthalide, 3.3-bis(1-(4-allylphenyl)-1-(4-diethylaminophenyl)
ethylene-2-yl]4.5,6.7-titrachlorophthalide, 3゜3-bis(1-(4-ethoxyphenyl)
-1-(2-dimethylaminophenyl)ethylene-2-
yl)-4,5,6,7-titrabromophthalide, 3.
3-bis(1-(4-N-tetrahydrofurfuryl-N
-methylaminophenyl)-1-(3chloro-4-ethoxyphenyl)ethylene-2-yl2-6-chloro-4
,5,7-) dibromophthalide, 3,3-bis(1-(
4-(2-phenoxyethyl)phenyl)-1-(4-
N-methyl-N-ethylaminophenyl)ethylene-2
-yl)-5-nitrophthalide, 3,3-bis(1-(
4-(2-p-chlorophenoxyethyl)phenyl)-
1-(4-N-methyl-N-ethylaminophenyl)ethylene-2-yl)-6-nitrophthalide, 3,3-bis(1-(4-N-pchlorophenyl-N-ethylaminophenyl)1- (3,4-dimethylphenyl)ethylene-2yl]-5-ethoxyphthalide, 3,3-bis(
1-(4-methoxyphenyl)-1-(4-pyrrolidinophenyl)ethylene-2-yl)phthalide, 3,3-bis(1-(3-nitrophenyl)1-(3-propargylphenyl)ethylene -2-yl)-4,5,6,7-titrafluorophthalide, 3,3-bis(1-(4-(2
-dimethylaminoethylamino)phenyl)-1-(3
-acetylphenyl)ethylene-2-yl)phthalide,
3.3-bis(1-(4= (3-diethylaminopropylac])phenyl)-1-(3-p-ethylbenzoylphenyl>ethylene-2-yl)-4,5,6,7
-Titrachlorophthalide, 3゜3-bis(1-(4-(
p-chlorophenyl)phenyl)-1-(4-phenethylphenyl)ethylene-2-yl)phthalide, 3.3-
Bis[1(2,6-dimethyl-4-tert-butylphenyl)-1-(4-aminophenyl)ethylene-2-
yl)-4,5,6,7-titrabromophthalide, 3.
3-bis(1-(4-n-butoxyphenyl)1-(
4-(N-cyclohexyl-N-methylamino)phenyl]ethylene-2-yl)-4゜5.6.7-titrapromofuclide, 3.3-bis(1-(2-methyl-4-
(2-methylmercaptoethyl)phenyl)-1-(4
-N,N-diarylaminophenyl)ethylene-2-yl) = 5,6-dichloro-4,7-dibromophthalide,
3.3-bis(1-(4-(3,3,5-)limethylcyclohexyl)phenyl)-1-(N-pmethylphenyl-N-ethylachnophenyl)ethylene-2-yl)
-4,5,6,7-titrabromophthalide, 3,3-bis(1-(2-methyl-4-chloroethoxypropylphenyl)-1-(2,6-diethyl-4=butylphenyl)ethylene- 2-yl]-5-chloro-4,6,7 tribromophthalide, 3,3-bisC1-(4-p-methylbenzoyloxyphenyl)-1-(3,5-dimethylphenyl)ethylene-2 -yl]-4,5,6-)lichlorophthalide, 3.3-bis(1-(4-methylmercaptophenyl)-1-(4-(N-p-)luoylphenyl-N-2butenylamino)phenyl ] Ethylene-2-yl)-4,5,6-)dibromophthalide, 3.3
-bis(1-(2-methyl-4-pyrrolidinophenyl)
-1-(3-chloro-4-methylphenyl)-1-propen-2-yl)-4,5,6,7-titrachlorophthalide, 3.3-bis(l-(4(3-o -)lylbropyl)phenyl]-1=(3-methyl-4-dibutylaminophenyl)l-buten-2-yl) -4,5,6,
7-titrachlorophthalide, 3.3-bis(1-(3-
Allyl-4-(2-p-ethylphenoxyethyl)phenyl)-1-(4-N-ethoxypropyl N-ethylaminophenyl)ethylene-2-yl)-5,6-dichloro-4,7-dibromophthalene do, 3.3-bis[1-(
2-methoxy-4-cyclohexylphenyl)-1-(
2-ethyl-4-chloroethylmercaptoethylphenyl)ethylene-2-yl]phthalide, 3,3-bis(1
-(4-(2-cyclohexylethyl)phenyl)-1
-(N-tetrahydrofurfuryl-N-β-methlylaminophenyl)ethylene-2-yl)-4゜5.6.7
-titrachlorophthalide, 3.3-bis (1-(4-
(3,3-dimethoxypropyl)phenyl)-1-(N
-p-chlorophenyl-N-isopropylaminophenyl)ethylene-2yl)-5-ethylphthalide, 3.3
-bis[1-(3,5-dichloro-4-dimethylaminophenyl)-1-phenylethylene-2-yl)-4゜5.6.7-titrabromophthalide, 3,3-bis(1
-(2-propionyloxy-4-pyrrolidinophenyl)-1-(2-chloro-4-ethoxyphenyl-5-methylphenyl)ethylene-2-yl)-5-butoxyphthalide, 3.3-bis( 1 (4-isoamylphenyl)
-1-phenylethylene-2-yl-4-nitrophthalide, 3.3-bis(1-(4-α-naphthylphenyl)1-(4-(N-3-methylcyclohexyl-N-
acetylamino)phenyl]ethylene-2-yl)-4
-nitrophthalide, 3.3-bis[1(4-p-dimethylaminophenylphenyl)-1-(4-morpholinophenyl)ethylene-2yl]-5-diallylaminophthalide, 3.3bis(1-( 4-isopropoxyphenyl)1-(4-piperazinophenyl)ethylene-2yl)
-4,5,6,7-titrachlorophthalide, 3.3-bis(1-(4-bromophenyl)-1(1-methyl-1)
, 2,3,4-tetrahydroquinolin-6-yl>ethylene-2-yl]-4゜5.6.7-titrachlorophthalide, 3,3-bis(1-(4-isopropoxyphenyl)- 1(2,2,4-1-tmethyl-1,2-dihydroquinolin-6-yl)ethylene-2-yl]-4゜5
．． 6.7-Titrachlorophthalide, 3.3-bis(1-
(2-acetylamino-4-piperidinophenyl)-1
-C2-acetoxy-4-(3゜5-dimethylphenoxy)phenyl]ethylene2-yl)phthalide, 3.3-
Bis[I-phenyl-1-(4-dimethylaminophenyl)ethylene-2-yl)-4,5,6,7-titrachlorophthalide, 3.3-bis[1-phenyl-1-(4
-pyrrolidinophenyl)ethylene-2-yl] ~4,5
, 6.7-titrachlorophthalide, 3゜3-bis(1-
(4-methoxyphenyl)-1(4-dimethylaminophenyl)ethylene-2yl)-4,5,6,7-titrachlorophthalide, 3.3-bis(1-(4-ethoxyphenyl)-1 -(4-'; dimethylaminophenylethylene-2-yl)-4,5,6,7-titrachlorophthalide, 3,3-bis(1-(4-methoxyphenyl)-
1-(4-pyrrolidinophenyl)ethylene-2-yl)
-4,5,6,7-titrachlorophthalide, 3,3-bis[1-(4-phenoxyphenyl)-1-(4-pyrrolidinophenyl)ethylene-2-yl)-4,5, 6,
7-tetrachlorophthalide, 3,3-bis(1-(4-
ethoxyphenyl)-1-(4-diethylaminophenyl〉ethylene-2-yl)-4,5,6,7-titrachlorophthalide, 3.3-bis(1-(4-butoxyphenyl)-1-( 4-piperidinophenyl〉ethylene-2
-yl)-4,5,6,7-titrachlorophthalide, 3
,3-bis(1-(2-methyl-4-methoxyphenyl)-1-(4-diethylaminophenyl)ethylene-2
-yl]-4゜5.6.7-titrachlorophthalide, 3
,3-bis(1-(2-methyl-4-methoxyphenyl)-1-(4-pyrrolidinophenyl)ethylene-2-yl)-4,5,6,7-titrachlorophthalide, 3,3
-bis(1-(3-chloro-4-ethoxyphenyl)-
1-(4-aminophenyl)ethylene-2-yl)-4
, 5,6,7-titrachlorophthalide, 3,3-bis(
1-(4-methoxyphenyl)-1-(2-methyl-4
-pyrrolidinophenyl)ethylene-2-yl) -4,
5,6゜7-titrachlorophthalide, 3,3-bis[1
(4-ethoxyphenyl)-1-(3-ethoxy4-diethylaminophenyl)ethylene-2-yl)-4,5
, 6,7-titrachlorophthalide, 3,3-bis(1-
(3-methylphenyl)-1-(4-N-methyl-N-
benzylaminophenyl)ethylene-2-yl) -4
, 5,6,7-titrachlorophthalide, 3,3-bis(
1-(3゜5-dichlorophenyl)-1-(4-hexamethyleneiminophenyl)ethylene-2-yl]-4゜5.6.7-titrachlorophthalide, 3.3-bis(1
-(4-ethoxyphenyl)-1-(4piperidinophenyl)ethylene-2-yl)-5゜6-benzophthalide, 3.3-bis[1-(4methylphenyl)-1-(julolidine-9- yl) ethylene-2-yl)-4,5
, 6,7-titrachlorophthalide, 3,3-bis(1-
(4propoxyphenyl)-1-(3-methyl-4pyrrolidinophenyl)ethylene-2-yl]-4゜7-diazaphthalide, 3,3-bis(1-(4-n-butylphenyl)- 1-(4-dimethylaminophenyl)ethylene-2-yl)-5,6-benzo-4,7-diazaphthalide, 3.3-bis[1-(3-ethyl-4-ethoxyphenyl)-1-( 4-diethylachnophenyl)ethylene-2-yl]-4-azaphthalide, 3.3-bis[(4-ethoxyphenyl)-1-(4-piperidinophenyl)ethylene-2-yl]-5- Di-n-butylaminophthalide, 3,3-bis[1-(4-ethoxyphenyl)-1-(4-piperidinophenyl)ethylene-2-yl]-6-dinitylaminophthalide, 3. 3-bis(1
-(4-methoxyphenyl)-1-(4-dimethylaminophenyl)ethylene-2-yl)-6-pyrrolidinophthalide, 3.3-bis(1-(4-N-methylN-β-
dimethylethylaminophenyl)-1-(4-fluorophenyl)ethylene-2-yl]4-azaphthalide, 3
．． 3-bis(1-(4N-ethyl-N-β-chloroethylaminophenyl)-1-(4-cyclohexyloxyphenyl)ethylene-2-yl]-4-azaphthalide,
3゜3-bis[1,1-bis(4-n-butylphenyl)ethylene-2-yl)-4,5,6,7-titrachlorophthalide, etc.

- 2-chloro-3-methyl-6-(p-(pphenylaminophenylamino)〉phenylamino)fluoran, 2
-Chloro-3-methyl-6-[p-(p'-(p'-chlorophenylamino)phenylamino)phenylaminocofluorane, 2-chloro-3-methyl-6-(p-
(p'-toluidinophenylamino)phenylamino)
Fluoran, 3-methyl-6-(p-(p'-phenylaminophenylamino)phenylamino)fluoran, 3-methyl-6-(p-(m'-)luidinophenylamino)phenylamino)fluoran, 2 .3-dimethyl-6-(p-(p'-phenylaminophenylamino)phenylamino)fluoran, 1,3.4-
) Dimethyl-6-(p-(p'-phenylaminophenylamino)phenylamino)fluorane, 2-cyclohexyl-6-(p-(p'-phenylaminophenylamino))phenylamino)fluorane, 2-phenyl −
6-(p-(p-phenylaminophenylamino)
phenylamino)fluoran, 2,3-dimethyl-6-
(p-(p-phenylaminophenylamino)phenylamino)-4',5',6',7'tetrachlorofluorane, 2-isoamyl-6(p-(p'-phenylaminophenylamino)) phenylamino) fluorane,
2-Methyl-6(p-(N-ethyl-N-p'-(N'
-ethyl-N'-phenylamino)phenylaminocophenylamino)fluoran, 3-(p-(p-
phenylaminophenylamino)phenylamino)fluoran, 2-chloro-3-methyl-6-(p-(p
−Phenylaminophenylamino〉phenylamino〕)−
4', 5', 6', 7'-tetrabromofluorane, 2
．． 3-dimethyl-6-[p(N-methyl-N-p'-(
N'-Methyl-N'-p'-tolylamino)phenylamino)phenylagonocofluorane, 3-methoxy-6
-(p-(p'-phenylaminophenylamino)phenylamino)fluorane, 3-chlorol:1-6- (p
-(p'-phenylaminophenylamino)phenylamino)fluorane, 2-tert-butyl-6(p-(
p'-phenylaminophenylamino)phenylamino)fluoran, 2-chloro-3=methyl-6-(p-(
p'-phenylaminophenylamino)-4',5',7'-trichloro-6'-furomofluorane, 2,3-dimethyl-6-(p-(p-phenylaminophenylamino)phenyl amino)-6'
-Chlorofluorane, 2-methyl-3-chloro-6-[
p (p'(m',m''-dimethoxyphenylamino)phenylamino)phenylaminocofluorane,3-chloro-6(p-(p'-(m-methyl-m#-
Chlorophenylamino)phenylamino)phenylaminocofluorane, 2,3 dimethyl-6-(p-(p'-
phenylaminophenylamino)-0-methyl-〇-chlorophenylamino)fluoran, 6-(p -(p
'-phenylaminophenylamino)phenylamino)1,2-benzofluorane, 6-(p-(p'-phenylaminophenylamino)phenylamino/)-3,4
-benzofluorane, 2-chloro3-methyl-6-(p
-(p'-dimethylaminophenylaq)phenylamino)fluorane, 3-methyl-6-(p-(p
'-Dimethylaminophenylamino))phenylamino)fluoran, 3-chloro-6-(p-(p'-dimethylaminophenylamino)phenylamino)fluoran, 2-chloro-3-methyl-6-(p- (p'
-diethylaminophenylamino)phenylamino)fluorane, 3-methyl-6-(p -(p'-diethylaminophenylamino)phenylamino)fluorane, 2-chloro-3-methyl-6-(p-(p' -Methylaminophenylaξ])phenylamino)fluorane,
3-Methyl-6-(p(p'-ethylaminophenylamino)phenylamino)fluoran, 2,3-dimethyl-6-(p-<p-dimethylaminophenylamino>phenylamino)fluoran, 1,3. 4-Trimethyl-6-(p-(p'-diethylaminophenylamino)phenylamino)fluorane, 2-cyclohexyl-6-(p-(p'-dimethylaminophenylamino)phenylamino) Fluoran, 2-phenyl-6
-(p-(p'-N-methylN-ethylaminophenylamino)phenylamino)fluorane, 2,3-dimethyl-6-(p(p'-dimethylaminophenylamino)phenylamino)-4',5 ',6',7'-tetrachlorofluorane, 2-isoamyl-6-(p -(
p'-diethylaminophenylamino)phenylamino)fluorane, 3-(p-(p'-di-npropylaminophenylamino)phenylamino)fluorane, 3-methoxy-6-(p-(pdimethylaminophenylamino)phenyl amino) fluorane, 6-(p
-(p-dimethylaminophenylamino)phenylamino)-1,2-benzofluorane, 6-(p
-(p'-diethylaminophenylamino)phenylamino)-3゜4-benzofluorane, 2-phenylamino-3methyl-6-(p-(p-phenylaminophenylamino)phenylamino)fluorane, 2 −
Phenylamino-6-(p-(p-phenylaminophenylamino)phenylamino)fluoran, 2-
Phenylamino-3-chloro-6-(p-(p'-phenylaminophenylamino)phenylamino)fluoran and the like.

- Produced by [■] ・Bis(p-dimethylaminostyryl)-p-methylphenylsulfonylmethane, bis(p-diethylaminostyryl)-p-methylphenylsulfonylmethane, bis(p-diethylaminostyryl)-p-methylphenylsulfonylmethane,
p-dimethylaminostyryl)-benzenesulfonylmethane, bis(p-diethylaminostyryl)-benzenesulfonylmethane, bis(p-pyrrolidinostyryl)-
p-methylphenylsulfonylmethane, bis(p-pyrrolidinostyryl)-benzenesulfonylmethane, bis(
p-dimethylaminostyryl)-p-chlorophenylsulfonylmethane, bis(p-dimethylaminostyryl)
-p-nitrophenylsulfonylmethane, bis(p-diethylaminostyryl)p-n-1'decylphenylsulfonylmethane, bis(p-pyrrolidinostyryl)-p
-dimethylaminophenylsulfonylmethane, bis(p
-di-n-butylaminostyryl)-p-methylphenylsulfonylmethane, bis[l,1-bis(p-dimethylaminophenyl)ethylene-2-yl]-benzenesulfonylmethane, bis(1-(p-dimethylaminophenyl)
-1-(p-methoxyphenyl)ethylene-2-yl2-p-methylphenylsulfonylmethane, bis(1-(
p-pyrrolidinophenyl)-1-(p-methoxyphenyl)ethylene-2-yl)-p-methylphenylsulfonylmethane, bis(1-(p-dimethylaminophenyl)-1-methylethylene-2-yl) p-benzenesulfonylmethane, bis(p-N-ethyl-N-isoamylaminostyryl)-pmethylphenylsulfonylmethane, and the like.

These various basic dyes can be used alone or in combination of two or more. Further, the amount of the basic dye used is 0.01 to 2 g per 1 rrf of the thermal recording material,
More preferably, it should be contained in the recording layer in an amount of about 0.05 to 1 g.

In the present invention, basic dyes represented by the general formulas [I] to (rV) as described above are used, but if necessary, in addition to the above basic dyes, various commonly known colorless dyes may be used. Alternatively, it is also possible to use a light-colored basic dye in combination. Specific examples include the following.

3.3-bis(p-dimethylaminophenyl)6-dimethylaminophthalide, 3.3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl')-3-(1,2 Dimethylindol-3-yl>phthalide, 3(p-dimethylaminophenyl)-1-
(2-methylindol-3-yl)phthalide, 3,3
Bis(2-dimethylindol-3-yl)-5-
Dimethylaminophthalide, 3. 3-bis(1,2-dimethylindol-3-yl)-6dimethylaminophthalide, 3.3-bis(9-ethylcarbazol-3-yl)-6-dimethylaminophthalide, 3.3-bis (2
-phenylindol-3-yl)-6-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-(
Triarylmethane dyes such as 1-methylpyrrol-3-yl)-6-dimethylaminophthalide, 44'-bis(
dimethylamino)benzhydrylbenzyl ether, N
-halophenyl-leucoauramine, N-2,4,5-
Diphenylmethane dyes such as trichlorophenyl leuco auramine, thiazine dyes such as benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran , 3-benzyl-spirodinaphthopyran,
Spiro dyes such as 3-methyl-naphtho-(6'methoxybenzo)spiropyran, 3-propylspiro-dibenzobilane, rhodamine-B-anilinolactam, rhodamine(p-nitroanilino)lactam, rhodamine(0-chloroanilino)lactam, etc. lactam dyes, 3-dimethylamino-7-methoxyfluoran, 3-diethylamino-6-methoxyfluoran, 3-diethylamino-
7-methoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7
-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3-(N-ethyl-p-)luidino)-7-methylfluorane, 3-diethylamino-7-
N-acetyl-N-methylaminofluorane, 3-diethylamino-7-N-methylaminofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-
Diethylamino-7-N-methyl-N-benzylaminofluorane, 3-diethylamino-'IN-chloroethyl-N-methylaminofluorane, 3-diethylamino-
7N-diethylaminofluorane, 3-(N-ethyl-
p-Toluidino)-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-p-toluidino)-6-
Methyl-7-(p-toluidino)fluorane, 3-diethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-7-(2-carbomethoxy-
phenylamino)fluorane, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-phenylaminofluorane, 3-pyrrolidino-6-methyl7-phenylaminofluorane, 3-piperidino6 -Methyl-
7-phenylaminofluorane, 3-diethylamino-
6-Methyl-7-kyzylidinofluorane, 3-diethylamino-7-(o-chlorophenylamino)fluoran, 3-di-n-butylamino-7-(o-chlorophenylamino)fluoran, 3-pyrrolidino-6- Methyl = 7
-pn-butylphenylaminofluorane, 3-diethylamino-7-(o-fluorophenylamino>fluorane, 3-di-n-butylamino-7-(o-fluorophenylamino)fluorane, 3-di- n-butylamino-6-methyl-7-phenylaminofluorane, 3
-(N-methyl-Nn-alkyl)amino-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-
N-n-amyl>amino-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-N-isoamyl)
amino-6-methyl-7-phenylaminofluorane,
3-(N-methyl-Nn-hexyl)amino-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-Nn-hexyl)amino-6-methyl-twophenylaminofluorane, Fluoran dyes such as 3-(N-ethyl-N to β-ethylhexyl)amino-6-methyl-7-phenylaminofluoran and 3-di-n-pentyl-6methyl-7-phenylaminofluoran. In addition, two or more types of these basic dyes can be used in combination as necessary.

Moreover, these basic dyes and the general formulas (13 to (IV
) The usage ratio with the basic dye represented by formula (1) is not particularly limited, but it is usually 0, 1 to 10 parts by weight per 1 part by weight of the dye represented by general formulas (1) to [■]. The other dyes mentioned above are preferably used in an amount of about 1 to 5 parts by weight.

Various materials are known for inorganic or organic coloring agents that develop color upon contact with basic dyes such as those mentioned above, such as activated clay,
Inorganic acidic substances such as acpargite, colloidal silica, aluminum silicate, 4ter t-butylphenol, 4-hydroxydiphenoxide, α-naphthol, β
-naphthol, 4-hydroxyacetophenol, 4-t
ert-octylcatechol, 2,2'-dihydroxydiphenol, 4,4'-isopropylidene bis(2-
tert-butylphenol), 4.4'-5ec-
Butylidene diphenol, 4-phenylphenol, 4
．． 4′-isopropylidenediphenol, 2°2-bis(4-hydroxyphenyl)-4-methylpentane, 2
, 2'-methylenebis(4-chlorophenol), hydroquinone, 4,4'-cyclohexylidene diphenol, 4,4'-dihydroxydiphenyl sulfide,
Hydroquinone monobenzyl ether, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone,
2.4.4'-IJ hydroxybenzophenone, 2.
2',4.4'-tetrahydroxybenzophenone, 4
-dimethyl hydroxyphthalate, methyl 4-hydroxybenzoate, 1-propyl 4-hydroxybenzoate, 5ec-butyl 4-hydroxybenzoate, pentyl 4-hydroxybenzoate, phenyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, Tolyl 4-hydroxybenzoate, chlorophenyl 4-hydroxybenzoate, phenylpropyl 4-hydroxybenzoate, phenethyl 4-hydroxybenzoate, p-chlorobenzyl 4-hydroxybenzoate, p-methoxybenzyl 4-hydroxybenzoate , novolak type phenolic resin, phenolic compounds such as phenol polymers, benzoic acid, ptert-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, 3
-sec-phthyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, 3-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3-(α -methylbenzyl)salicylic acid, 3-chloro-5=(α-methylbenzyl)salicylic acid, 3.5-di-tert-butylsalicylic acid, 3-phenyl-5(α,α-dimethylbenzyl)salicylic acid, 3゜5-di-tert-butylsalicylic acid, - Aromatic carboxylic acids such as α-methylbenzylsalicylic acid, 4,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, bis(3-allyl-4-
hydroxyphenyl) sulfone, 4-hydroxy-4'
- 4-hydroxydiphenylsulfone derivatives such as methyldiphenylsulfone, 3.4-dihydroxydiphenylsulfone, 3.4-dihydroxy-41-methyldiphenylsulfone, bis(3-tert-butyl-4-hydroxy-6-methylphenyl) Sulfide, bis(2-
Sulfide derivatives such as methyl-4-hydroxy-5-tert-butylphenyl) sulfide, as well as these phenolic compounds, aromatic carboxylic acids, etc., such as zinc, magnesium, aluminum, calcium, titanium, etc.
Examples include salts with polyvalent metals such as manganese, tin, and nickel, and organic acidic substances such as antipyrine complexes of zinc thiocyanate.

The ratio of the basic dye to the coloring agent should be selected appropriately depending on the type of basic dye and coloring agent used, and is not particularly limited, but generally 1 part by weight of the basic dye. ~50 parts by weight, preferably 1 to 10 parts by weight, of colorants are used.

Coating liquids containing these heat-sensitive materials are generally prepared by using water as a dispersion medium and separately dispersing the basic dye and coloring agent using a stirring/pulverizing machine such as a ball mill, vertical attritor or horizontal sand mill, etc. prepared.

As mentioned above, the present invention is characterized in that the specific graft copolymer is blended into the heat-sensitive recording layer. The amount of the graft copolymer used is not particularly limited, but it is 0% based on the total solid content of the recording layer.
．． If it is less than 1% by weight, a sufficient effect cannot be obtained, and if it exceeds 10% by weight, the recording sensitivity may decrease. It is desirable to mix it in a range of 0.5 to 5% by weight.

Although the specific graft copolymer used in the present invention also functions as a binder, it is generally desirable to use a known binder together. Specific examples of such binders include starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, gum arabic, polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, diisobutylene/maleic anhydride copolymer salt, styrene, etc. Maleic anhydride copolymer salt, ethylene/
Examples include acrylic acid copolymer salts, styrene/acrylic acid copolymer salts, styrene/butadiene copolymer emulsions, urea resins, melan resins, amide resins, etc., and these are usually included in the total solid content of the coating liquid. It is used in an amount of 1 to 70% by weight, preferably 4 to 30% by weight, based on the box size.

Furthermore, various auxiliary agents can be added to the coating liquid as necessary, such as dispersants such as sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium lauryl alcohol sulfate, fatty acid metal salts, etc. , ultraviolet absorbers such as benzophenone, other antifoaming agents, fluorescent dyes, coloring dyes, etc. are added as appropriate.

In addition, waxes such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, and ester wax, kaolin, clay, talc, calcium carbonate, calcined kaolin, titanium oxide, diatomaceous earth, fine particulate anhydrous silica, It is also possible to add inorganic pigments such as activated clay, among others, from the viewpoint of maintaining whiteness, it is preferable to use 1 to 10 weight degrees of calcium carbonate based on the total solid content. Moreover, a sensitizer can also be used in combination depending on the purpose. Specific examples of the sensitizer include stearic acid amide, stearic acid methylene bisamide, oleic acid amide, palmitic acid amide, fatty acid amides such as coconut fatty acid amide, 2.2'-
Methylenebis(4-methyl-6-tert-butylphenol), 4゜4'-butylidenebis(6-tert-butyl-3methylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2
UV absorption of hindered phenols such as 4-diter t-butyl-3-methylphenol, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-benzyloxybenzophenone, etc. agent, 1,2-di(3-methylphenoxy)ethane, 1,2-diphenoxyethane, 1-phenoxy-2-
Examples include (4-methylphenoxy)ethane, dimethyl terephthalate, dibutyl terephthalate, dibenzyl terephthalate, diptyl isophthalate, phenyl 1-hydroxynaphthoate, and various known thermofusible substances.

The amount of the sensitizer used is not particularly limited, but it is generally desirable to adjust the amount to about 4 parts by weight or less per 1 part by weight of the coloring agent.

The method for forming the recording layer is not particularly limited; for example, the recording layer coating liquid is applied to the support by an appropriate coating method such as air knife coating, variper blade coating, pure blade coating, short dwell coating, curtain coating, etc. and dried. It is formed by such methods as

The amount of coating liquid applied is also not particularly limited, and is usually 2 to 1 on dry weight.
2 g/n (preferably adjusted in a range of about 3 to IO g/m).

As the support, paper, plastic film, synthetic paper, etc. can be used, but paper is most preferably used in terms of cost, coatability, etc.

The heat-sensitive recording material of the present invention thus obtained has effective improvement in background fog, extremely remarkable reduction in optical contrast between the printed area and the background area due to temperature and humidity, and is resistant to changes in the external environment. It is possible to maintain an excellent PC8 value even when the temperature is high.

Note that, if necessary, it is possible to further improve the storage stability by providing a protective layer on the recording layer or also providing a protective layer on the back side of the heat-sensitive recording material. Furthermore, various known techniques in the field of heat-sensitive recording material manufacturing may be added as necessary, such as providing an undercoat layer on the support, applying an adhesive treatment to the back surface of the recording material, and processing it into an adhesive label.

"Examples" The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto unless it goes beyond the gist of the present invention. Further, parts and % in the examples represent parts by weight and % by weight, respectively, unless otherwise specified.

Example 1 ■ Preparation of liquid A 3.3-bis(1-(4-methoxyphenyl)1-(4
-dimethylaminophenyl)ethylene-2-yl)-4
,5,6,7-titrachlorophthalide
4 parts 3-di-n-butylamino-6-methyl-7phenylaminofluorane 10 parts Methyl cellulose 5% aqueous solution 5 parts water
40 parts of this composition was ground in a sand mill to an average particle size of 3 μm.

■ Preparation of Solution B 4. 4'-isopropylidene diphenol 30 parts Methyl cellulose 5% aqueous solution 5 parts water
55 parts of this composition was pulverized in a sand grinder to an average particle size of 3 μm.

■ C-wave preparation 1.2-bis-(3-methylphenoxy)ethane

20 parts methyl cellulose 5% water mWL
5 parts water
55 parts This composition was milled with a sand mill to an average particle size of 3 μm.
crushed to.

■ Formation of recording layer 59 parts of liquid A, 90 parts of liquid B, 80 parts of liquid C, silicon oxide pigment (
15 parts (oil absorption 180 m1/100 g), 2 parts calcium carbonate, 30 parts of 20% starch oxide aqueous solution, 60 wt% ammonium salt of styrene-acrylic acid copolymer [60 wt% Step 1/40 wt% acrylic acid]. A recording layer coating liquid was prepared by mixing and stirring 10 parts of a 25% aqueous solution of a graft copolymer with 40% by weight of acrylamide and 10 parts of water. The obtained coating liquid was applied to a base paper of 100 g/rd to a dry weight of 5 g/rd and dried to obtain a thermal recording paper.

Example 2 In preparing Solution A, 3,3-bis(1-(4methoxyphenyl)-1-(4-dimethylaminophenyl)ethylene-2-yl)-4,5,6°7-titrachlorophthalene 3゜3-bis(1-(4-methoxyphenyl)-1(4-pyrrolidinophenyl)ethylene-
2-yl]-4.5,6.7-titrachlorophthalide 4
A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 50% of the thermal recording paper was used.

Example 3 In preparing Solution A, 3,3-bis(1-(4methoxyphenyl)-i(4-dimethylaminophenyl)ethylene-2-yl)-4,5,6°7-titrachlorophthalide Instead of 4 parts, 3゜6-bis(dimethylamino)fluorene-9-spiro-3'-(6'-dimethylamino)
A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 4 parts of phthalide was used.

Example 4 In preparing Solution A, 3,3-bis(1-(4methoxyphenyll-1-(4-dimethylaminophenyl)ethylene-2-yl)-4,5,6°7-titrachlorophthalide A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 4 parts of 3(p-(p'-phenylaminophenylamino))phenylamino)fluorane was used instead of 4 parts.

Example 5 In preparing Solution A, 3,3-bis(1-(4methoxyphenyl)-1-(4-dimethylaminophenyl)ethylene-2-yl)-4,5,6°7-titrachlorophthalene A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 4 parts of bis(p-dimethylaminostyryl)-p-methylphenylsulfonylmethane was used instead of 4 parts of methane.

Example 6 In Example 1, a 25% aqueous solution of a graft copolymer of 60% by weight of ammonium salt of styrene/acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic acid] and 40% by weight of acrylamide was prepared. Instead of 10 parts, add 10 parts of a 25% aqueous solution of a graft copolymer of 70% by weight of ammonium salt of styrene/acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic] and 30% by weight of methyl acrylate. A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 50% of the thermal recording paper was used.

Example 7 In Example 1, a 25% aqueous solution of a graft copolymer of 60% by weight of ammonium salt of styrene/acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic acid] and 40% by weight of acrylamide was prepared. Instead of 10 parts, 1 part of a 25% aqueous solution of a graft copolymer of 70% by weight of potassium salt of styrene/acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic acid] and 30% by weight of acrylonitrile.
A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 0 part was used.

Example 8 In Example 1, a 25% aqueous solution of a graft copolymer of 60% by weight of ammonium salt of styrene/acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic acid] and 140% by weight of acrylic 75 was prepared. Instead of 10 parts, add 10 parts of a 25% aqueous solution of a graft copolymer of 70% by weight of ammonium salt of styrene-acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic] and 30% by weight of maleic acid.
A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 50% of the thermal recording paper was used.

Example 9 In Example 1, a 25% aqueous solution of a graft copolymer of 60% by weight of ammonium salt of styrene/acrylic acid copolymer [60% by weight of Steton/40% by weight of acrylic acid] and 140% by weight of acrylic acid was prepared. Instead of 10 parts, 60% by weight of ammonium salt of styrene-acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic], 30% by weight of acrylamide and 10% by weight of maleic acid were used. A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 10 parts of a 25% aqueous solution was used.

Example 10 A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 2 parts of calcium carbonate was not used in the formation of the recording layer in Example 1.

Comparative Example 1 In Example 1, a 25% aqueous solution of a graft copolymer of 60% by weight of ammonium salt of styrene/acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic acid] and 40% by weight of acrylamide was used. except that instead of 10 parts, 20 parts of a 10% solution of polyvinyl alcohol was used.
A thermosensitive recording paper was obtained in the same manner as in Example 1.

Comparative Example 2 In Example 1, a 25% aqueous solution of a graft copolymer of 60% by weight of ammonium salt of styrene/acrylic acid copolymer [60% by weight of Step 1/40% by weight of acrylic acid] and 40% by weight of acrylamide was used. A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 10 parts was not used.

Comparative Example 3 In Example 5, 10 parts of a 25% aqueous solution of a graft copolymer of 60% by weight of ammonium salt of styrene/acrylic M copolymer [60% by weight of Stereph/40% by weight of acrylic acid] and 40% by weight of acrylamide was used. A thermosensitive recording paper was obtained in the same manner as in Example 5 except that .

The 13 types of thermal recording paper obtained as described above were evaluated in the following items, and the results are listed in Table 1.

[Skin fog]

The heat-sensitive recording paper was treated for 48 hours at 40° C. and 50% RH, and the whiteness after treatment was measured using a Hunter whiteness meter.

[Heat resistance in near-infrared region]

Heat-sensitive recording paper was pressed for 5 seconds on a heating plate at 120°C (4 kg/c
ut) to develop color, then heat the recording paper at 60°C for 4 hours.
It was treated for 8 hours. Regarding the recording paper after processing, wavelength 830
The reflectance (%) of the recorded image and the background part in nm was measured using a spectrophotometer, and the PC3 value was calculated. In addition, PC3
The value was calculated using the following formula.

The PCS value required for recording paper varies depending on the type of optical character reading device used, but it is generally in the range of 0.7 to 1.0, preferably 0.75 to 1.0 in the reading wavelength range. required.

[Moisture resistance in near-infrared region]

Heat-sensitive recording paper colored in the same manner as above was heated at 50°C and 75°C.
The sample was treated under conditions of %RH for 48 hours, and the PC3 value after the treatment was measured and calculated in the same manner as above.

"Effect" As is clear from the results of each example, the heat-sensitive recording material of the present invention maintains a high PCS value even when stored under high temperature or high humidity conditions, and has extremely low background fog. It was a heat-sensitive recording material with high commercial value.

Claims (1)

[Claims] (1) In a heat-sensitive recording material provided with a heat-sensitive recording layer on a support that utilizes a color reaction between a colorless or light-colored basic dye and a coloring agent that can develop a color when it comes into contact with the dye, the recording The layer contains at least one compound represented by the following general formulas [I] to [IV] as a basic dye, and (a) styrene/(meth)acrylic acid copolymer [styrene 60 to 80% by weight / (meth)acrylic acid 20 to 40% by weight] and (b) an acrylamide monomer, an acrylonitrile monomer, an acrylic ester monomer, and an acrylic acid monomer. 1. A heat-sensitive recording material comprising a graft copolymer with 10 to 80% by weight of at least one monomer selected from the following. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [In the formula, R_1 to R_6 are hydrogen atoms, respectively; C_1 to
C_8 alkyl group; C_5 to C_8 cycloalkyl group; C_3 to C_8 alkoxyalkyl group; C_3 to
C_9 unsaturated alkyl group; tetrahydrofurfuryl group; tetrahydropyran-2-methyl group; halogen atom,
C_1 to C_4 alkyl group, C_1 to C_4 aralkyl group which may be substituted with an alkoxyl group; halogen atom, C_1 to C_4 alkyl group, aryl group which may be substituted with a C_1 to C_4 alkoxyl group; halogen atom , C_1 to C_4 alkyl group, C_1 to C_4
represents a C_2 to C_8 alkyl group having a phenoxy group which may be substituted with an alkoxyl group. Furthermore, R_1 and R_2, R_3 and R_4, and R_5 and R_6 can also form a heterocycle with each other or with an adjacent benzene ring. ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [II] [In the formula, R_7 to R_16 are each a hydrogen atom; a halogen atom; a nitro group; a saturated or unsaturated alkyl group of C_1 to C_9 which may be substituted; It may be C_5~
C_8 cycloalkyl group; C_1- which may be substituted
C_4 alkoxyl group; C_2 to C which may be substituted
_6 acyloxy group; optionally substituted C_6 to C_1
Aryl group of _0; C_7 to C_12 which may be substituted
an aralkyl group; an optionally substituted phenoxy group; an optionally substituted C_1 to C_4 thioalkoxyl group;
Amino group▲There are mathematical formulas, chemical formulas, tables, etc.▼(R_1_
8, R_1_9 is each a hydrogen atom; C_ which may be substituted
1 to C_9 saturated or unsaturated alkyl group; optionally substituted C_5 to C_8 cycloalkyl group; optionally substituted C_6 to C_1_0 aryl group; optionally substituted C_7 to C_12 aralkyl group; tetrahydro Furfuryl group; represents an optionally substituted C_2 to C_6 acyl group, but can also form a heterocycle with each other or with adjacent benzene rings. ), and R_1_7 is a hydrogen atom; C_1 to C_4 are alkyl groups. a, b, c
, d each represent a carbon atom, but 1 to 2 of them may be nitrogen atoms. Hydrogen atoms; halogen atoms; C_1 to C_4 alkyl groups; C_
1 to C_4 alkoxyl group; optionally substituted amino group; nitro group may be bonded, and a-b, b-c or c-d bond may form another aromatic ring. ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [III] [In the formula, R_2_0 is a halogen atom; C_1 to C_8 alkyl groups; C_1 to C_4 alkoxyl groups; cyclohexyl group; phenyl group; optionally substituted amino group , R_2_1 and R_2_3 are each hydrogen atoms; C_1
~C_4 represents an alkyl group, R_2_2, R_2_4
are each a halogen atom; C_1 to C_4 alkyl group; C
Indicates an alkoxyl group of _1 to C_4. R_2_5, R
_2_6 are each hydrogen atoms; C_1 to C may be substituted
_9 saturated or unsaturated alkyl group; optionally substituted C
_5 to C_8 cycloalkyl group; optionally substituted C
Aryl group of _6 to C_1_0; C_ which may be substituted
It shows an aralkyl group of 7 to C_12; a tetrahydrofurfuryl group; an acyl group of C_2 to C_6; and a sulfonyl group. X represents a halogen atom, and l, m, n, and k each represent 0 or an integer of 1 to 4. Further, the broken line indicates that a naphthalene ring may be formed with an adjacent benzene ring. ]▲There are mathematical formulas, chemical formulas, tables, etc.▼[IV] [In the formula, R_2_7 to R_3_0 are C_1 to C, respectively.
_8 alkyl group; C_5 to C_8 cycloalkyl group; C_3 to C_8 alkoxyalkyl group; C_3 to C
Indicates the unsaturated alkyl group of _9. Also, R_2_7 and R_
2_8, R_2_9 and R_3_0 may form a heterocycle with each other or with an adjacent benzene ring. R_3_1,
R_3_2 is each hydrogen atom; C_1 to C_4 alkyl group; halogen atom, C_1 to C_4 alkyl group, C_
R_3_3 represents an optionally substituted C_1-C_4 alkyl group; R_3_3 represents an optionally substituted phenyl group. ]