JP2022146926A - Color developer, heat-sensitive recording material, and coating for heat-sensitive recording layer - Google Patents

Abstract

To provide a color developer that has excellent plasticizer resistance.SOLUTION: Provided is a color developer for a heat-sensitive recording layer, represented by the following general formula (1) or the following general formula (2). (R0-X)-Y-(Z) --- (2). R1, R2 and R3 each represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group or an allyl group, and, in the general formula (2), R0 represents an alkyl group having an aryl group, or an aryl group optionally having a substituent of an alkyl group, an aralkyl group, an aryl group, or an alkoxy group, X represents -OCO-, -SO2NHCO-, -NHCO-, -NHCS-, or -SO2- attached to the N-terminus of Y, Y is a peptide residue other than a cystine residue, and Z represents an OH group or an OR" group that binds to the C-terminus of Y.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a developer, a heat-sensitive recording material, and a coating material for a heat-sensitive recording layer.

A heat-sensitive recording material having a heat-sensitive recording layer provided on a support is used in various industrial fields. A thermosensitive recording layer containing a colorless or pale-colored basic dye at room temperature and an organic color developer, and capable of obtaining color recording by applying heat energy (Jule heat) from a thermosensitive head, a thermal pen, etc., and a thermosensitive recording layer containing the same Recording materials have already been widely put into practical use.

The required performance of the printed portion formed by the heat-sensitive recording material is affected by, for example, basic dyes, color developers, sensitizers, etc., which are components of the heat-sensitive recording material, and the color developer has a particularly large effect. As color developers, petrochemical-derived synthetic compounds such as phenolic compounds and sulfonylurea compounds have been proposed. Among them, many phenolic compounds have been developed and put to practical use.

For example, 4,4'-dihydroxydiphenylsulfone (Patent Document 1) has been proposed.

JP-A-57-11088

However, although the diphenylsulfone derivatives such as 4,4'-dihydroxydiphenylsulfone described in Patent Document 1 have good printing properties, etc., they have low resistance to plasticizers. There is a risk of

Accordingly, an object of the present invention is to provide a color developer, a heat-sensitive recording material and a heat-sensitive recording wear coating which are excellent in plasticizer resistance.

前記一般式（１）中、
Ｒ^１及びＲ^２は、それぞれ、水素原子、Ｃ１～Ｃ８のアルキル基、Ｃ１～Ｃ８のアルコキシ基、Ｃ７～Ｃ１１のアラルキル基、又はアリル基を表し、
Ｒ^３は、水素原子、Ｃ１～Ｃ８のアルキル基、Ｃ７～Ｃ１１のアラルキル基、又はアリル基を表し、
Ｒ^１、Ｒ^２及びＲ^３は、互いに同一でも異なっていてもよく、
Ｒ^１が複数の場合は、各Ｒ^１は互いに同一でも異なっていてもよく、
Ｒ^２が複数の場合は、各Ｒ^２は互いに同一でも異なっていてもよく、
Ｒ^３が複数の場合は、各Ｒ^３は互いに同一でも異なっていてもよい。

（Ｒ^０－Ｘ）－Ｙ－（Ｚ） ・・・（２）

前記一般式（２）中、
Ｒ^０はＣ６～Ｃ１０のアリール基を有するアルキル基、又は、Ｃ１～Ｃ８のアルキル基、Ｃ７～Ｃ１１のアラルキル基、Ｃ６～Ｃ１０のアリール基、若しくはＣ１～Ｃ８のアルコキシ基の置換基を有していてもよいアリール基を表し、
Ｘは、ＹのＮ末端に結合する基であって、－ＯＣＯ－、－ＳＯ_２ＮＨＣＯ－、－ＮＨＣＯ－、－ＮＨＣＳ－、又は－ＳＯ_２－を表し、
Ｙは、アミノ酸残基又はペプチド残基を表し、Ｙ基中の、セリン残基、スレオニン残基、アスパラギン酸残基、グルタミン酸残基、又はチロシン残基のＯＨ基は、ＯＲ^０基又はＯＲ”基に置換していてもよく、システイン残基のＳＨ基は、ＳＲ^０基又はＳＲ”基に置換していてもよく、ヒスチジン残基のＮＨ基は、ＮＲ^０基又はＮＲ’基に置換していてもよく、リシン残基又はオルニチン残基のＮＨ_２基は、ＮＨＲ^０基又はＮＨＲ’基に置換していてもよく、Ｒ’はアミノ保護基を表し、Ｒ”はカルボキシ保護基を表し、
ただし、Ｙは、シスチン残基以外のアミノ酸残基、又はシスチン残基を有さないペプチド残基であり、
Ｚは、ＹのＣ末端に結合する基であって、ＯＨ基又はＯＲ”基を表し、
複数のＲ^０、Ｒ’及びＲ”は、互いに同一でも異なっていてもよく、
Ｒ^０が複数の場合は、各Ｒ^０は互いに同一でも異なっていてもよく、
Ｒ’が複数の場合は、各Ｒ’は互いに同一でも異なっていてもよく、
Ｒ”が複数の場合は、各Ｒ”は互いに同一でも異なっていてもよく、
Ｒ^０、Ｒ’及びＲ”のうち２つ以上の基が互いに結合して環を形成していてもよい。 In order to achieve the above object, the developer of the present invention
A developer for a thermosensitive recording layer,
It is characterized by containing a 4-hydroxydiphenylsulfone derivative represented by the following general formula (1) and an N-substituted amino acid derivative represented by the following general formula (2).

In the general formula (1),
R ¹ and R ² each represent a hydrogen atom, a C1-C8 alkyl group, a C1-C8 alkoxy group, a C7-C11 aralkyl group, or an allyl group;
R ³ represents a hydrogen atom, a C1-C8 alkyl group, a C7-C11 aralkyl group, or an allyl group;
R ¹ , R ² and R ³ may be the same or different,
When R ¹ is plural, each R ¹ may be the same or different,
When R ² is plural, each R ² may be the same or different,
When R ³ is plural, each R ³ may be the same or different.

(R ⁰ -X)-Y-(Z) (2)

In the general formula (2),
R ⁰ is an alkyl group having a C6-C10 aryl group, or has a substituent of a C1-C8 alkyl group, a C7-C11 aralkyl group, a C6-C10 aryl group, or a C1-C8 alkoxy group; represents an aryl group that may be
X is a group that binds to the N-terminus of Y and represents -OCO-, -SO _{2 NHCO-, -NHCO-, -NHCS- or -SO 2 -} ;
Y represents an amino acid residue or a peptide residue, and the OH group of a serine residue, a threonine residue, an aspartic acid residue, a glutamic acid residue, or a tyrosine residue in the Y group is an OR ⁰ group or an OR" The SH group of the cysteine residue may be substituted with an SR ⁰ group or an SR″ group, and the NH group of the histidine residue may be substituted with an NR ⁰ group or an NR′ group. the _NH2 group of a lysine residue or an ornithine residue may be substituted with an NHR ⁰ group or an NHR' group, where R' represents an amino protecting group and R" represents a carboxy protecting group. ,
provided that Y is an amino acid residue other than a cystine residue, or a peptide residue that does not have a cystine residue,
Z is a group that binds to the C-terminal of Y and represents an OH group or an OR″ group;
A plurality of R ⁰ , R′ and R″ may be the same or different,
When R ⁰ is plural, each R ⁰ may be the same or different,
When there are multiple R', each R' may be the same or different,
When R" is plural, each R" may be the same or different,
Two or more groups of R ⁰ , R′ and R″ may be bonded together to form a ring.

The heat-sensitive recording material of the present invention is
A thermosensitive recording material having a thermosensitive recording layer on a support,
The thermosensitive recording layer contains a colorless or light-colored basic dye at room temperature and a developer capable of developing color upon contact with the basic dye by heating,
The color developer is the color developer of the present invention.

The coating material for the heat-sensitive recording layer of the present invention is
A heat-sensitive recording layer coating for use in forming a heat-sensitive recording layer,
Containing a colorless or light-colored basic dye at room temperature and a developer capable of developing color upon contact with the basic dye upon heating,
The color developer is the color developer of the present invention.

According to the present invention, it is possible to provide a color developer, a heat-sensitive recording material, and a layer coating material for a heat-sensitive recording layer, which are excellent in plasticizer resistance.

As described above, the color developer, the heat-sensitive recording material, and the heat-sensitive recording layer coating material of the present invention contain the 4-hydroxydiphenylsulfone derivative represented by the general formula (1) as the color developer, and the general formula ( The N-substituted amino acid derivative represented by 2) is used in combination. According to this, for example, the plasticizer resistance is further improved without reducing the color density, whiteness, and various good storage properties of the 4-hydroxydiphenylsulfone derivative represented by the general formula (1). can do

Performances required for thermosensitive recording materials include whiteness of unprinted areas, color density of printed areas, storage stability of printed areas, and the like under various environmental conditions.

The storage stability of the printed part is the stability when the printed part is placed in an environment of heat and high humidity, the stability when water adheres, the stability when oils and alcohols adhere, It means the performance of the print part's persistence due to these external factors, such as the stability when attached to the plasticizer used to bring out the plasticity of tanning used in leather products such as synthetic leather and film products. .

In particular, thermal recording materials are often used for POS cash register paper. POS cash register paper is sometimes stored in leather or synthetic leather wallets for a long period of time, and there is a possibility that the printed portion of the POS cash register paper will disappear due to the plasticizer. On the other hand, in food label applications, film products such as wraps used may come into direct contact with food label paper, and the plasticizer in the film product may erase the printed portion of the food label paper. Thus, the plasticizer resistance of the printed portion is one of the most important items for the storage stability of the heat-sensitive recording material.

As described above, the color developer, heat-sensitive recording material, and heat-sensitive recording layer coating material of the present invention are excellent in plasticizer resistance, and are therefore suitable for use in the above-mentioned POS register paper, food labels, and the like. It can be used for a wide range of applications without being limited to

The 4-hydroxydiphenylsulfone derivative represented by the general formula (1) is excellent in, for example, printing properties, heat resistance, wet heat resistance, water resistance and the like. In the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the 4-hydroxydiphenylsulfone derivative represented by the general formula (1) is N-substituted by the general formula (2). By using an amino acid derivative in combination, for example, the 4-hydroxydiphenylsulfone derivative represented by the general formula (1) has excellent printing properties, heat resistance, moist heat resistance, water resistance, etc., while maintaining plasticizer resistance. can be further improved.

In the present invention, compounds (e.g., compounds represented by the general formula (1), compounds represented by the general formula (2), etc.) are tautomers or stereoisomers (e.g., geometric isomers, ligands). If there are isomers such as stereoisomers and optical isomers), any isomers can be used in the present invention unless otherwise specified. In addition, when a compound can form a salt, the salt can also be used in the present invention unless otherwise specified. The salt may be an acid addition salt or a base addition salt. Furthermore, the acid forming the acid addition salt may be an inorganic acid or an organic acid, and the base forming the base addition salt may be an inorganic base or an organic base. Examples of the inorganic acid include, but are not limited to, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypofluorous acid, hypochlorous acid, hypobromous acid, Hypoiodous acid, fluorous acid, chlorous acid, bromous acid, iodous acid, fluoric acid, chloric acid, bromic acid, iodic acid, perfluoric acid, perchloric acid, perbromic acid, periodic acid, etc. is mentioned. The organic acid is also not particularly limited, but examples thereof include p-toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromobenzenesulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid and acetic acid. The inorganic base is not particularly limited, but includes, for example, ammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide, carbonate and hydrogen carbonate. More specifically, for example, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, calcium hydroxide and calcium carbonate; The organic base is also not particularly limited, and examples thereof include ethanolamine, triethylamine and tris(hydroxymethyl)aminomethane. The method for producing these salts is not particularly limited, either, and they can be produced, for example, by adding an acid or base as described above to the above compounds as appropriate by a known method.

Further, in the present invention, chain substituents (e.g., hydrocarbon groups such as alkyl groups and unsaturated aliphatic hydrocarbon groups) may be linear or branched unless otherwise specified, and the number of carbon atoms thereof is , but not particularly limited, for example, 1 to 40, 1 to 32, 1 to 24, 1 to 18, 1 to 12, 1 to 6, or 1 to 2 (2 or more in the case of an unsaturated hydrocarbon group) can be In the present invention, the number of ring members (the number of atoms constituting the ring) of the cyclic group (e.g., aryl group, heteroaryl group, etc.) is not particularly limited. ~18, 6-12, or 6-10. In addition, when there are isomers in a substituent or the like, any isomers may be used unless otherwise specified. For example, simply referred to as a "naphthyl group" may be a 1-naphthyl group or a 2-naphthyl group.

In the general formula (2), the alkyl group having a C6-C10 aryl group is not particularly limited, but examples thereof include a benzyl group (phenylmethyl group), a phenethyl group (phenylethyl group), a phenylpropyl group, A phenylbutyl group, a phenylpropyl group, and the like can be mentioned. In the present invention, "an alkyl group having a C6-C10 aryl group" refers to a group in which at least one hydrogen of an alkyl group is substituted with a C6-C10 aryl group.

In the general formula (1), the C1-C8 alkyl group or cycloalkyl group for R ¹ , R ² and R ³ is not particularly limited, but examples include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group, octyl group, isohexyl group, 2-methylpentyl group, 2-methylhexyl group, 2- Linear or branched alkyl groups such as ethylpentyl group, 2-ethylhexyl group, 3-methylpentyl group, 3-methylhexyl group, 3-ethylpentyl group, and 3-ethylhexyl group can be mentioned. In addition, instead of these alkyl groups, cycloalkyl groups such as cyclopropyl, cyclobutyl, 2-methylcyclopropyl, cyclopropylmethyl, cyclopentyl and cyclohexyl groups can be mentioned. The C1-C8 alkyl group for R ¹ , R ² and R ³ is preferably a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group or tert-butyl group, and propyl or isopropyl groups are more preferred. A propyl group or an isopropyl group is particularly preferred as the C1-C8 alkyl group for R ³ .

In the general formula (1), the C7-C11 aralkyl group for R ¹ , R ² and R ³ is not particularly limited, but examples include benzyl group (phenylmethyl group), phenethyl group (phenylethyl group), phenylpropylated phenyl, phenylbutyl, phenylpropyl, and naphthylmethyl groups. Naphthylmethyl groups include 1-naphthylmethyl groups and 2-naphthylmethyl groups. The C7-C11 aralkyl group for R ¹ , R ² and R ³ is preferably a phenylmethyl group, and the C7-C11 aralkyl group for R ³ is particularly preferably a phenylmethyl group.

In the general formula (1), the C1 to C8 alkoxy groups in R ¹ and R ² are not particularly limited, but examples include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec -butoxy group, t-butoxy group, pentyloxy group, isopentyloxy group, neopentyloxy group, hexyloxy group, isohexyloxy group, heptyloxy group, octyloxy group, etc. linear or branched Alkoxyl groups may be mentioned. Also, for example, it is preferable that neither of R ¹ and R ² is an alkoxy group, or only one of them is an alkoxy group.

When R ¹ , R ² and R ³ contain an allyl group, for example, R ¹ and R ² are preferably allyl groups.

In the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the 4-hydroxydiphenylsulfone derivative represented by the general formula (1) is not particularly limited, but for example, 4,4'-dihydroxydiphenyl Sulfone, 2,4-dihydroxydiphenylsulfone, 4-hydroxy-4'-i-propoxydiphenylsulfone, 4-hydroxy-4'-n-propoxydiphenylsulfone, 4-hydroxy-4'-benzyloxydiphenylsulfone, bis( 3-allyl-4-hydroxyphenyl)sulfone, 4-[(4-allyloxy)phenylsulfonyl]phenol, 4-benzyloxy-4'-hydroxydiphenylsulfone, and the like. From the viewpoint of better plasticizer resistance, the 4-hydroxydiphenylsulfone derivative represented by the general formula (1) includes 4,4′-dihydroxydiphenylsulfone and bis(3-allyl-4-hydroxyphenyl ) sulfones. Incidentally, bis(3-aryl-4-hydroxyphenyl) sulfone, for example, in powder X-ray diffractometry using Cu-Kα rays, according to an X-ray diffraction diagram having peaks at at least diffraction angles of 7.2° and 22.0° It is preferred to have a characterized crystalline form. However, bis(3-allyl-4-hydroxyphenyl)sulfone is not limited to bis(3-allyl-4-hydroxyphenyl)sulfone having this crystal form, and is optional.

Hereinafter, in this specification, the 4-hydroxydiphenylsulfone derivative represented by the general formula (1) is sometimes referred to as "color developer (B)".

In the heat-sensitive recording layer of the heat-sensitive recording material of the present invention or the heat-sensitive recording layer coating material of the present invention, the content of the developer (B) is not particularly limited, but from the viewpoint of color density, the heat-sensitive recording layer It is preferably 30 to 800 parts by mass, more preferably 50 to 500 parts by mass, and even more preferably 100 to 400 parts by mass with respect to 100 parts by mass of the basic dye.

In the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the color developer contains an N-substituted amino acid derivative represented by the following general formula (2), as described above.

(R ⁰ -X)-Y-(Z) (2)

In the general formula (2), R ⁰ is an alkyl group having a C6-C10 aryl group, or a C1-C8 alkyl group, a C7-C11 aralkyl group, a C6-C10 aryl group, or a C1-C8 represents an aryl group optionally having an alkoxy substituent. Examples of the alkyl group having a C6-C10 aryl group include a benzyl group, a phenethyl group, an o-tolylmethyl group, an m-tolylmethyl group, a p-tolylmethyl group, an o-tolylethyl group, an m-tolylethyl group, and a p-tolylethyl group. mentioned. Examples of the aryl group which may have a C1 to C8 alkyl group substituent include o-tolyl group, m-tolyl group, p-tolyl group, 1-ethylphenyl group, 2-ethylphenyl group, 3-ethyl phenyl group, 1-propylphenyl group, 2-propylphenyl group, 3-propylphenyl group, 1-butylphenyl group, 2-butylphenyl group, 3-butylphenyl group, 1-pentylphenyl group, 2-pentylphenyl group , 3-pentylphenyl group, and the like. Examples of the aryl group optionally having a substituent of the C7-C11 aralkyl group include a p-benzylbiphenyl group. Examples of the C6-C10 aryl group which may have a substituent include a biphenyl group and a 3,3'-dimethylbiphenyl group. The aryl group optionally having a C1-C8 alkoxy group substituent includes a 6-methoxyphenyl group.

In the general formula (2), X is a group that binds to the N-terminus of Y, and as described above, -OCO-, -SO _{2 NHCO-, -NHCO-, -NHCS-, or SO 2 -} ( sulfonyl group).

In the general formula (2), Y represents an amino acid residue or a peptide residue as described above, and a serine residue, a threonine residue, an aspartic acid residue, a glutamic acid residue, or a tyrosine residue in the Y group. The OH group of the group may be substituted with an OR ⁰ group or an OR" group, the SH group of a cysteine residue may be substituted with an SR ⁰ group or an SR" group, the NH group of a histidine residue may be substituted with an NR ⁰ group or an NR' group, the NH ₂ group of a lysine residue or an ornithine residue may be substituted with an NHR ⁰ group or an NHR' group, and R' is an amino-protected and R″ represents a carboxy-protecting group. As an amino _- protecting group (R′ group) protecting the NH group of a histidine residue in the Y group, or the NH group of a lysine residue or an ornithine residue, , for example, R ⁰ X groups, and also acyl groups and alkyl groups.The carboxy-protecting group (R″ group) for protecting the aspartic acid residue or glutamic acid residue in the Y group includes alkoxy groups, aryloxy groups, amino groups, alkylamino groups, arylamino groups, and the like. In addition, examples of protective groups for the OH group of serine, threonine, or tyrosine residues in the Y group, or the SH groups of cysteine residues include the aforementioned carboxy protective groups (R″ groups).

However, as described above, Y is an amino acid residue other than a cystine residue or a peptide residue without a cystine residue.

In the general formula (2), Z is a group bonded to the C terminal of Y as described above, and represents an OH group or an OR″ group.

In the general formula (2), as described above,
R ⁰ , R′ and R″ may be the same or different,
When R ⁰ is plural, each R ⁰ may be the same or different,
When there are multiple R', each R' may be the same or different,
When R" is plural, each R" may be the same or different,
Two or more groups of R ⁰ , R′ and R″ may be bonded together to form a ring.

The method for producing the N-substituted amino acid derivative represented by the general formula (2) is not particularly limited. or an isocyanate compound.

Amino acids, peptides, and esters and amides thereof used as constituents of the N-substituted amino acid derivative represented by the general formula (2) are not particularly limited, and may be L-form or D-form. or DL-body. The amino acid may be, for example, a natural amino acid, an unnatural amino acid, an α-amino acid, or a β-amino acid. Examples of the ester include, but are not limited to, C1 to C4 alkyl esters, aryl esters, aralkyl esters, and the like. The amides include, but are not limited to, amides, alkyl-substituted amides, aryl-substituted amides, and the like.

Specific examples of amino acids, peptides, and esters and amides thereof used as constituents of the N-substituted amino acid derivative represented by the general formula (2) include glycine, glycine methyl ester, glycine ethyl ester, ester derivatives such as glycine-tert-butyl ester, glycine phenyl ester, glycine p-cresyl ester, glycine m-cresyl ester, glycine benzyl ester; amide derivatives such as glycinamide, N'-methylglycinamide, glycylanilide; ester derivatives such as glycine, phenylglycine methyl ester, phenylglycine ethyl ester, phenylglycine benzyl ester; , ester derivatives such as phenylalanine methyl ester, phenylalanine ethyl ester, and phenylalanine benzyl ester; amide derivatives such as phenylalanine amide, N′-methylphenylalanine amide, and phenylalanyl anilide; Ester derivatives such as valine-tert-butyl ester and valine benzyl ester, valinamide, leucine, leucine methyl ester, isoleucine, serine, o-substituted serine such as o-methylserine, o-benzylserine, serine methyl ester, serine benzyl ester, etc. ester derivatives of threonine, o-substituted threonine such as o-methylthreonine, o-benzylthreonine, ester derivatives such as threonine methyl ester, threonine-tert-butyl ester, tyrosine, o-methoxytyrosine, o-benzyloxytyrosine, o-substituted tyrosines such as tyrosine, 3-(3′,4′-dihydroxyphenyl)alanine (DOPA), ester derivatives such as tyrosine methyl ester, tyrosine benzyl ester, tyrosinamide, proline, hydroxyproline, proline methyl ester, proline -tert-butyl ester, ester derivatives such as proline benzyl ester, proline amide, lysine, ornithine, lysine methyl ester, lysine ethyl ester, lysine benzyl ester, ornithine methyl ester ornithine ethyl ester, ester derivatives such as ornithine benzyl ester, arginine, arginine methyl ester, arginine ethyl ester, histidine, histidine methyl ester, tryptophan, tryptophan methyl ester, tryptophan benzyl ester, tryptophanamide, cysteine, cystine, S-methyl S-substituted cysteine such as cysteine, S-ethylcysteine, S-benzylcysteine, S-phenylcysteine, ester derivatives such as cysteine methyl ester, cysteine benzyl ester and S-oxidized derivatives such as cysteine sulfoxide and sulfone, methionine, methionine sulfoxide , S-oxidized derivatives such as methionine sulfone, ester derivatives such as methionine methyl ester, methionine benzyl ester, ester derivatives such as methionine amide, aspartic acid, aspartic acid methyl ester, aspartic acid ethyl ester, aspartic acid benzyl ester, asparagine, glutamic acid , glutamic acid methyl ester, glutamic acid ethyl ester, ester derivatives such as glutamic acid benzyl ester, and glutamine. Furthermore, amino acids such as homoserine, homocysteine, norleucine, and derivatives thereof may be used. In addition, C1-C8 aminocarboxylic acids such as β-alanine, 5-aminovaleric acid and 7-aminoheptanoic acid are also selected.

Examples of the peptide include, but are not limited to, glycylglycine, glycylglycine methyl ester, glycylglycinamide, glycylalanine, glycylalanine methyl ester, glycylvaline, glycylleucine, glycylphenylalanine, glycylphenylalanine methyl ester, glycylphenylalanine amide, glycylproline, alanylalanine, alanylproline, alanylmethionine, alanylmethionine methyl ester, alanylphenylalanine, glycylglycylglycine and the like.

The N-substituted amino acid derivative represented by the general formula (2) is, for example, an amino acid, peptide, or derivative thereof whose amino group is protected. The protecting group is not particularly limited, and may be, for example, a protecting group commonly used in the fields of amino acid chemistry or peptide synthesis chemistry.

In the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the functional group (-XNH- group ) is not particularly limited, but includes, for example, a sulfonylamino group, a urethane group, a (thio)urea group (ureid), and a sulfonylurea group. These functional groups, for example, sulfonylamino groups are derived from arylsulfonyl chlorides. The urethane group is derived from a chloroformate such as chloroformate benzyl ester or a carbonic acid ester such as diphenyl carbonate. The (thio)urea group is derived from an iso(thio)cyanate such as phenyl iso(thio)cyanate. Sulfonylureas are derived from sulfonylureas such as toluenesulfonyl isocyanate.

The compound (X1) forming a sulfonylamino group is not particularly limited, but specific examples include benzenesulfonyl chloride, p-toluenesulfonyl chloride, m-toluenesulfonyl chloride, o-toluenesulfonyl chloride, p- Chlorides such as methoxybenzenesulfonyl, p-xylenesulfonyl chloride, m-xylenesulfonyl chloride, mesitylenesulfonyl chloride, 1-naphthalenesulfonyl chloride and 2-naphthalenesulfonyl chloride, bromides and iodides.

The compound (X2) forming a urethane group is not particularly limited, but examples thereof include halogenated formic acid esters such as benzyl chloroformate and phenyl chloroformate, and carbonate esters such as diphenyl carbonate and dibenzyl carbonate.

The compound (X3) forming a (thio)urea group is not particularly limited, but examples include benzyl isocyanate, phenyl isocyanate, p-tolyl isocyanate, m-tolyl isocyanate, o-tolyl isocyanate, 1-naphthyl isocyanate, 2- naphthyl isocyanate, phenylene 1,4-diisocyanate (1,4-phenylene-diisocyanate), phenylene 1,3-diisocyanate (1,3-phenylene-diisocyanate), tolylene 2,4-diisocyanate, tolylene-2,6-diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, naphthalene 1,5-diisocyanate (1,5-naphthalenediyl-diisocyanate), 4,4'-diisocyanato-3,3'-dimethylbiphenyl, methylenediphenyl-4,4'-diisocyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenylmethane, phenylisothiocyanate, m-tolylisothiocyanate, p-tolylisothiocyanate and the like.

The compound (X4) forming a sulfonylurea group is not particularly limited, but examples thereof include benzenesulfonyl isocyanate and p-toluenesulfonyl isocyanate.

The N-substituted amino acid derivative obtained using the compound (X1) forming a sulfonylamino group in the general formula (2) is not particularly limited, but examples include N-benzenesulfonyl-glycine, N-benzenesulfonyl -glycine methyl ester, N-benzenesulfonyl-glycinamide, N-benzenesulfonyl-methionine methyl ester, N-benzenesulfonyl-cysteine-S-benzyl, N-(p-toluenesulfonyl)-glycine, N-(p-toluene sulfonyl)-alanine, N-(p-toluenesulfonyl)-β-alanine, N-(p-toluenesulfonyl)-phenylalanine, N-(p-toluenesulfonyl)-phenylalanine methyl ester, N-(p-toluenesulfonyl) -phenylalanine benzyl ester, N-(p-toluenesulfonyl)-methionine, N-(p-toluenesulfonyl)-methionine benzyl ester, N-(m-toluenesulfonyl)-isoleucine, 3-N-(o-toluenesulfonyl) aminocaproic acid, N-(2,4-xylenesulfonyl)-alanine, N-(2,4,6-mesitylenesulfonyl)-serine, N-(p-ethylbenzenesulfonyl)-threonine, N,N'-di(p -tert-butylbenzenesulfonyl)-lysine, N,N'-di(p-tert-butylbenzenesulfonyl)-ornithine, N-(1-naphthalenesulfonyl)-tryptophan, N-2-naphthalenesulfonyl-asparagine, etc. -arylsulfonyl-amino acids, esters and amides, N-aralkylsulfonyl-amino acids, esters and amides such as N-benzylsulfonyl-valine, N-benzylsulfonyl-tyrosine, N-benzylsulfonyl-phenylglycine and the like.

The N-substituted amino acid derivative obtained using the compound (X3) forming a urea group in the general formula (2) is not particularly limited, but examples include N-phenylaminocarbonyl-glycine, N-phenylamino Carbonyl-glycine-methyl ester, N-phenylaminocarbonyl-glycinebenzyl ester, N-phenylaminocarbonyl-glycinamide, N-phenylaminocarbonyl-alanine, N-phenylaminocarbonyl-alanine-methyl ester, N-phenylaminocarbonyl -β-alanine, N-phenylaminocarbonyl-methionine, N-phenylaminocarbonyl-methionine-methyl ester, N-phenylaminocarbonyl-glutamine, N,N'-di(phenylaminocarbonyl)-lysine, N,N' -di(phenylaminocarbonyl)-ornithine, N-phenylaminocarbonyl-phenylalanine, N-phenylaminocarbonyl-norvaline, N-(p-tolylaminocarbonyl)-glycine, N-(p-tolylaminocarbonyl)-alanine, N-(p-tolylaminocarbonyl)-valine, N-(p-tolylaminocarbonyl)-phenylalanine, N-(p-tolylaminocarbonyl)-cysteine-S-benzyl, N-(p-tolylaminocarbonyl)- Methionine, N-(p-tolylaminocarbonyl)-glutamic acid, N-(p-tolylaminocarbonyl)-glutamine, N-(m-tolylaminocarbonyl)-glycine, N-(p-tolylaminocarbonyl)-glycyl glycine, N-(p-tolylaminocarbonyl)-glycylglycylglycine, N-(m-tolylaminocarbonyl)-glycylalanine, N-(m-tolylaminocarbonyl)-leucylalanine, N-(m- tolylaminocarbonyl)-methionine, N-(m-tolylaminocarbonyl)-methionine-sulfone, N-(m-tolylaminocarbonyl)-valine, N-(m-tolylaminocarbonyl)-tyrosine, N-(m- tolylaminocarbonyl)-tyrosine-methyl ester, N-(m-tolylaminocarbonyl)-phenylalanine, N-(phenylaminocarbonyl)-phenylalanine, N-(m-tolylaminocarbonyl)-methionine, N-(m-tolyl) aminocarbonyl)-valine, N-(m-tolylaminocarbonyl)-phenylglycine, N-phenylglycine , N-(3-isopropenyl-α,α-dimethylbenzyl)aminocarbonyl-methionine, and N-(m-tolylaminocarbonyl)-tyrosine. .

Other examples of N-substituted amino acid derivatives obtained using the compound (X3) forming a urea group include N-(m-tolylaminocarbonyl)-phenylalanine-methyl ester, N-(m-tolyl aminocarbonyl)-phenylalanine-ethyl ester, N-(m-tolylaminocarbonyl)-phenylalanine-benzyl ester, N-(phenylaminocarbonyl)-phenylalanine-methyl ester, N-(phenylaminocarbonyl)-phenylalanine-ethyl ester, N-(phenylaminocarbonyl)-phenylalanine-benzyl ester, N-(m-tolylaminocarbonyl)-β-phenylalaninamide, N,N'-di(m-tolylaminocarbonyl)-lysine, N,N'-di (m-tolylaminocarbonyl)-lysine-methyl ester, N,N'-di(m-tolylaminocarbonyl)-ornithine, N,N'-di(m-tolylaminocarbonyl)-ornithine-methyl ester, N- (m-tolylaminocarbonyl)-glutamic acid, N-(o-tolylaminocarbonyl)-alanine, N-(o-tolylaminocarbonyl)-homoserine, N-(o-tolylaminocarbonyl)-valine, 1,6- hexamethylenebis(N-aminocarbonyl-phenylalanine), 2,4-phenylenebis(N-aminocarbonyl-phenylalanine), 1,3-tolylenbis(N-aminocarbonyl-phenylglycine) and the like.

The N-substituted amino acid derivative obtained using the compound (X3) forming a thiourea group in the general formula (2) is not particularly limited, but examples include N-phenylaminothiocarbonyl-phenylalanine, N- Phenylaminothiocarbonyl-phenylalanine-methyl ester, N-phenylaminothiocarbonyl-valine-isopropyl ester, N-phenylaminothiocarbonyl-tyrosine-methyl ester, N-phenylaminothiocarbonyl-methionine-methyl ester, N-phenylamino Thiocarbonyl-glycylglycine, N-phenylaminothiocarbonyl-glycylalanine, Nm-tolylaminothiocarbonyl-phenylalanine, Nm-tolylaminothiocarbonyl-phenylalanine-benzyl ester, Nm-tolylaminothio carbonyl-phenylalaninamide, Nm-tolylaminothiocarbonyl-valine, Nm-tolylaminothiocarbonyl-valine-isopropyl ester, Nm-tolylaminothiocarbonyl-methionine-methyl ester, Nm-tolylamino Thiocarbonyl-glycylglycine, Np-tolylaminothiocarbonyl-phenylalanine, Np-tolylaminothiocarbonyl-phenylalanine-benzyl ester, Np-tolylaminothiocarbonyl-phenylalanineamide, Np-tolylamino Thiocarbonyl-valine, Np-tolylaminothiocarbonyl-valine-isopropyl ester, Np-tolylaminothiocarbonyl-methionine-methyl ester, Np-tolylaminothiocarbonyl-glycylglycine and the like.

The N-substituted amino acid derivative obtained using the compound (X2) forming a urethane group in the general formula (2) is not particularly limited, but examples include N-benzyloxycarbonyl-glycine, N-benzyloxy carbonyl-phenylglycine, N-benzyloxycarbonyl-valine, N-benzyloxycarbonyl-methionine, N-benzyloxycarbonyl-tyrosine, N-benzyloxycarbonyl-hydroxyproline, N-benzyloxycarbonyl-arginine, N-benzyloxy carbonyl-glycine and the like.

In the general formula (2), the N-substituted amino acid derivative obtained using the compound (X4) forming a sulfonylurea group is not particularly limited, but for example, N-(p-toluenesulfonylaminocarbonyl )-glycine, N-(p-toluenesulfonylaminocarbonyl)-phenylalanine, N-(p-toluenesulfonylaminocarbonyl)-phenylalanine-methyl ester, N-(p-toluenesulfonylaminocarbonyl)-phenylalanine-ethyl ester, N -(p-toluenesulfonylaminocarbonyl)-phenylalanineamide, N-(p-toluenesulfonylaminocarbonyl)-β-alanine, N-(p-toluenesulfonylaminocarbonyl)-β-alanine-methyl ester, N-(p -toluenesulfonylaminocarbonyl)-methionine-methyl ester, N-(p-toluenesulfonylaminocarbonyl)-leucine, N,N'-di(p-toluenesulfonylaminocarbonyl)-lysine-methyl ester, N,N'- and di(p-toluenesulfonylaminocarbonyl)-ornithine-methyl ester.

In the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the NH group of the histidine residue in the Y group of the N-substituted amino acid derivative represented by the general formula (2) or the lysine residue The amino-protecting group (R' group) protecting the NH ₂ group of the group or the ornithine residue includes R ⁰ X group, and also acyl group and alkyl group. These amino-protecting groups (R' groups) can be introduced by known methods. For example, acyl groups can be introduced using acid anhydrides. Alkyl groups can be introduced, for example, with alkyl halides such as trityl chloride in the presence of amines and the like.

Protecting the aspartic acid residue or glutamic acid residue in the Y group of the N-substituted amino acid derivative represented by the general formula (2) in the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention Carboxy-protecting groups (R″ groups) include alkoxy groups, aryloxy groups, amino groups, alkylamino groups, arylamino groups, etc. Also, serine, threonine, or tyrosine residues in the Y group. or the SH group of a cysteine residue includes the aforementioned carboxy-protecting group (R″ group). These carboxy-protecting groups (R″ groups) can be introduced by known methods.

In the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the N-substituted amino acid derivative preferred as the color developer represented by the general formula (2) is not particularly limited, but for example, N- N-allylsulfonyl-amino acids such as (p-toluenesulfonyl)-glycine, N-(p-toluenesulfonyl)-alanine, N-(p-toluenesulfonyl)-β-alanine, N-phenylaminocarbonyl-glycine, N -phenylaminocarbonyl-valine, N-(m-tolylaminocarbonyl)-phenylalanine, N-(phenylaminocarbonyl)-phenylalanine, N-(m-tolylaminocarbonyl)-cysteine-S-benzyl, N-(m- tolylaminocarbonyl)-methionine, N-(m-tolylaminocarbonyl)-tyrosine, N-(p-tolylaminocarbonyl)-phenylalanine, N-(p-tolylaminocarbonyl)-cysteine-S-benzyl, N-( N-aminocarbonyl-amino acids such as p-tolylaminocarbonyl)-methionine, N-(p-tolylaminocarbonyl)-methionine, N-(phenylaminocarbonyl)-methionine, N-(p-tolylaminocarbonyl)-tyrosine and particularly preferably N-(m-tolylaminocarbonyl)-phenylalanine, N-(phenylaminocarbonyl)-phenylalanine, N-(m-tolylaminocarbonyl)-methionine, N-(p-tolylaminocarbonyl) -methionine, N-(phenylaminocarbonyl)-methionine, N-(m-tolylaminocarbonyl)-valine, N-(m-tolylaminocarbonyl)-phenylglycine and N-(m-tolylaminocarbonyl)-tyrosine can be mentioned.

In the general formula (2), Z is preferably an OH group, X is preferably a -NHCO- group, specifically, the N-substituted amino acid derivative is N-(m-tolylaminocarbonyl) -phenylalanine, N-(m-tolylaminocarbonyl)-methionine, N-(p-tolylaminocarbonyl)-methionine, N-(phenylaminocarbonyl)-methionine, N-(m-tolylaminocarbonyl)-valine, N It is preferable to use at least one selected from the group consisting of -(m-tolylaminocarbonyl)-phenylglycine and N-(m-tolylaminocarbonyl)-tyrosine.

As the color developer represented by the general formula (2), these N-substituted amino acid derivatives may be used singly or in combination of two or more.

N-substituted amino acid derivatives such as N-(m-tolylaminocarbonyl)-phenylalanine and N-(phenylaminocarbonyl)-phenylalanine represented by the general formula (2) used in the present invention are However, from the viewpoint of whether amino acids, which are also food products, can be used in heat-sensitive recording materials, they found that they can be used as color developers. Amino acids have a basic amino group and an acidic carboxy group coexisting in the same molecule and are neutralized in the molecule, so that they do not develop color even when they come into contact with a basic dye.

The present inventors have found that intramolecular neutralization is eliminated by introducing a functional group that contributes to the required performance and color developing ability as a color developer of a heat-sensitive recording material as a protective group for the amino group of an amino acid, and furthermore, the amino acid In particular, he has proposed an invention relating to a heat-sensitive recording material using an N-substituted amino acid derivative made from a natural amino acid as a color developer (Japanese Patent No. 6726048). The N-substituted amino acid derivative represented by the general formula (2) is a color developer described in Japanese Patent No. 6726048.

Hereinafter, in this specification, the N-substituted amino acid derivative represented by the general formula (2) may be referred to as a color developer (C).

In the heat-sensitive recording layer coating material of the present invention or the heat-sensitive recording layer of the heat-sensitive recording material of the present invention, the content of the developer (C) is determined from the viewpoint of color density and plasticizer resistance. It is preferably 5 to 400 parts by mass, more preferably 8 to 300 parts by mass, and more preferably 10 to 200 parts by mass with respect to 100 parts by mass of the basic dye.

In the color developer of the present invention, the heat-sensitive recording layer coating material of the present invention, or the heat-sensitive recording layer of the heat-sensitive recording material of the present invention, the content of the color developer (C) is not particularly limited. From the viewpoint of the property, it may be, for example, 1 part by mass or more, preferably 3 parts by mass or more, more preferably 4 parts by mass or more, and further 5 parts by mass with respect to 100 parts by mass of the developer (B). or more, preferably 10 parts by mass or more, preferably 14 parts by mass or more, preferably 20 parts by mass or more, preferably 30 parts by mass or more, preferably 40 parts by mass or more, preferably 60 parts by mass or more, 80 parts by mass or more is preferred.

In the developer of the present invention, the coating material for a heat-sensitive recording layer of the present invention, or the heat-sensitive recording layer of the heat-sensitive recording material of the present invention, the content of the developer (C) with respect to 100 parts by mass of the developer (B) Although the upper limit of the amount is not particularly limited, it is preferably an appropriate amount within the range where the effect of plasticizer resistance can be obtained. Specifically, for example, it may be 500 parts by mass or less, 450 parts by mass or less, 300 parts by mass or less, 200 parts by mass or less, or 100 parts by mass. It may be below.

In the heat-sensitive recording layer, the total content of the developer (B) and the developer (C) is 35 to 500 parts by weight with respect to 100 parts by weight of the basic dye in the heat-sensitive recording layer from the viewpoint of color density. parts, more preferably 40 to 400 parts by mass, and more preferably 60 to 300 parts by mass.

In the heat-sensitive recording layer coating material of the present invention or the heat-sensitive recording layer of the heat-sensitive recording material of the present invention, the total content of the color developer (B) and the color developer (C) is not particularly limited. From the viewpoint of density, for example, 1 to 500 parts by weight, 5 to 300 parts by weight, 10 to 200 parts by weight, 10 to 100 parts by weight, and 14 to 100 parts by weight with respect to 100 parts by weight of the basic dye in the thermosensitive recording layer. , or preferably 30 to 100 parts by mass, and, for example, preferably 35 to 500 parts by mass, more preferably 40 to 400 parts by mass, and more preferably 60 to 300 parts by mass.

In the color developer, heat-sensitive recording material, and heat-sensitive recording layer coating material of the present invention, the color developer (B) and the color developer (C) are used within a range that does not impair the effects of the present invention. A color developer other than the colorant (B) and the color developer (C) may be used in combination. The other developer is not particularly limited, and may be any known or existing developer, for example. When the other color developer is used, one type of the other color developer may be used alone, or two or more types may be used in combination.

In the heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the colorless or light-colored basic dye at room temperature is not particularly limited, but examples include triphenylmethane-based, fluoran-based, diphenylmethane-based, spiro-based, fluorene-based, and thiazine dyes. system compounds and the like. The colorless or light-colored basic dye at room temperature can be selected from conventionally known leuco dyes, for example. The colorless or pale-colored basic dye at room temperature is preferably a colorless or pale-colored basic dye that is solid at room temperature, more preferably a colorless or pale-colored basic dye with a melting point of 60°C or higher, and a melting point of 130°C. The above colorless or light-colored basic dyes are more preferred.

In addition, in this invention, room temperature may be sufficient as "normal temperature", for example. In the present invention, “normal temperature” or “room temperature” may be, for example, −10° C. or higher, −5° C. or higher, 0° C. or higher, 5° C. or higher, or 10° C. or higher. ℃ or less, 50 ℃ or less, 45 ℃ or less, 40 ℃ or less, 35 ℃ or less, or 30 ℃ or less. That is, in the present invention, the "colorless or light-colored basic dye at normal temperature" is, for example, the temperature range of the "normal temperature" or "room temperature" (e.g., -10 ° C. to 60 ° C. or 10 ° C. to 30 ° C. temperature range) and colorless or light-colored basic dyes. In the present invention, the "colorless or light-colored basic dye that is solid at normal temperature" is, for example, the temperature range of the "normal temperature" or "room temperature" (for example, -10 ° C. to 60 ° C. or 10 ° C. to 30 It may be a colorless or light-colored basic dye that is solid in a temperature range such as °C.

In the present invention, the "colorless or light-colored basic dye at room temperature" may be any basic dye that can be used in the heat-sensitive recording layer of the heat-sensitive recording material by developing color upon heating. Such basic dyes are not particularly limited. There may be. The specific examples thereof are also not particularly limited, but are as described above, for example. In the present invention, "light color" is not particularly limited, but may be, for example, pale yellow, pale blue, or the like.

In the heat-sensitive recording material and heat-sensitive recording layer coating composition of the present invention, specific examples of colorless or light-colored basic dyes at room temperature are as follows. However, in the heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, the colorless or light-colored basic dye at room temperature is not limited to the following specific examples. In the heat-sensitive recording material and heat-sensitive recording layer coating composition of the present invention, the colorless or light-colored basic dyes at room temperature may be used singly or in combination of two or more.

[Specific examples of colorless or light-colored basic dyes at room temperature]
3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)phthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-( 1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3,3-bis(P-methylaminophenyl)-6-dimethylaminophthalide, 3-diethylamino-7-dibenzylaminobenzo[α ] Fluorane, 3-(1-ethyl-2-methylindol-3-yl)-3-(4-diethylamino-2-n-hexyloxyphenyl)-4-azaphthalide, 3-(1-ethyl-2-methyl Indol-3-yl)-3-(4-diethylamino)-2-methylphenyl-4-azaphthalide, 3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide , 3-(2-methyl-1-n-octylindol-3-yl)-3-(4-diethylamino-2-ethoxyphenyl)-4-azaphthalide, 3-(N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-(o,p-dimethylanilino)fluorane, 3- (N-ethyl-Np-toluidino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-(N,N-dibutylamino)-6 -methyl-7-anilinofluorane, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluorane, 3-diethylamino-7-(o-chloroanilino)fluorane, 3-diethylamino -7-(m-trifluoromethylanilino)fluorane, 3-di(n-pentyl)amino-6-methyl-7-anilinofluorane, 3-[N-(3-ethoxypropyl)-N-ethyl amino]6-methyl-7-anilinofluorane, 3-(Nn-hexyl-N-ethylamino)-7-(o-chloroanilino)fluorane, 3-(N-ethyl-N-2-tetrahydrofuran furylamino)-6-methyl-7-anilinofluorane, 2,2-bis{4-[6′-(N-cyclohexyl-N-methylamino)-3′-methylspiro[phthalide-3,9′- xanthene]-2′-ylamino]phenyl}propane, and 3-dibutylamino-7-(o-chloroa nilino)fluorane, 3,6-dimethoxyfluorane, 3-pyrrolidino-6-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino- 7,8-dibenzofluorane, 3-diethylamino-6,7-dimethylfluorane, 3-(N-methyl-p-toluidino)-7-methylfluorane, 3-(N-methyl-N-isoamylamino) -7,8-benzofluorane, 3,3′-bis(1-n-amyl-2-methylindol-3-yl)phthalide, 3-(N-methyl-N-isoamylamino)-7-phenoxyfluor orane, 3,3′-bis(1-n-butyl-2-methylindol-3-yl)phthalide, 3,3′-bis(1-ethyl-2-methylindol-3-yl)phthalide, 3, 3′-bis(p-dimethylaminophenyl)phthalide, 3-(N-ethyl-Np-tolylamino)-7-(N-phenyl-N-methylamino)fluorane, 3-diethylamino-7-anilinoflurane Olan, 3-diethylamino-7-benzylaminofluorane, 3-pyrrolidino-7-dibenzylaminofluorane

As described above, the heat-sensitive recording layer in the heat-sensitive recording material of the present invention and the coating material for the heat-sensitive recording layer of the present invention are colorless or light-colored at normal temperature, and are colored by contact with the basic dye upon heating. It may or may not contain optional components other than these.

Examples of the optional component include a sensitizer. Although the sensitizer is not particularly limited, for example, conventionally known sensitizers can be used in combination. Specific examples of the sensitizer include stearic acid amide, bis-stearic acid amide, fatty acid amide such as palmitic acid amide, p-toluenesulfonamide, stearic acid, calcium such as behenic acid and palmitic acid, zinc Alternatively, fatty acid metal salts such as aluminum, p-benzylbiphenyl, diphenylsulfone, benzyl benzyloxybenzoate, 2-benzyloxynaphthalene, 1,2-bis(p-tolyloxy)ethane, 1,2-bis(phenoxy)ethane, 1,2-bis(3-methylphenoxy)ethane, 1,3-bis(phenoxy)propane, dibenzyl oxalate, p-methylbenzyl oxalate, m-terphenyl, 1-hydroxy-2-naphthoic acid and the like. be done.

Further, for example, 2-benzyloxynaphthalene, 1,2-bis(p-tolyloxy)ethane, 1,2-bis(phenoxy)ethane, 1,2-bis(3-methylphenoxy)ethane, 1,3-bis One or more selected from (phenoxy)propane, dibenzyl oxalate, p-methylbenzyl oxalate, m-terphenyl, and 1-hydroxy-2-naphthoic acid may be used in combination with benzoin.

Examples of the optional component include storage stabilizers. Although the storage stabilizer is not particularly limited, for example, a conventionally known storage stabilizer can be used in combination. Specific examples of the storage stabilizer include 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 2,2′-methylenebis(4-ethyl-6-tert-butylphenol), 2,2′-ethylidenebis(4,6-di-tert-butylphenol), 4,4′-thiobis(2-methyl-6-tert-butylphenol), 4,4′-butylidenebis(6-tert-butylm -cresol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4′-bis[(4-methyl-3-phenoxycarbonylaminophenyl)ureido]diphenylsulfone, tris(2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl)isocyanurate, 4, 4'-thiobis(3-methylphenol), 4,4'-dihydroxy-3,3',5,5'-tetrabromodiphenylsulfone, 4,4'-dihydroxy-3,3',5,5'-tetra methyldiphenylsulfone, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy -3,5-dimethylphenyl)propane and other hindered phenol compounds, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenylsulfone, 4-benzyloxy-4'-(2-methylglycyl Epoxy compounds such as oxy)diphenylsulfone, glycidyl terephthalate, bisphenol A type epoxy resin type, cresol novolac type epoxy resin, phenol novolak type epoxy resin, N,N'-di-2-naphthyl-p-phenylenediamine, 2, 2′-methylenebis(4,6-di-tert-butylphenyl) sodium salt or polyvalent metal salt of phosphate, bis(4-ethyleneiminecarbonylaminophenyl)methane, 4,4′-bis[(4-methyl- 3-Phenoxycarbonylaminophenyl)ureido]diphenylsulfone and diphenylsulfone crosslinked compounds represented by the following formula (3). These storage stabilizers contribute to the storage stability of the printed portion of the heat-sensitive recording material.

（式中、ｎは１～７の整数を表す。）

(In the formula, n represents an integer of 1 to 7.)

When using a storage stabilizer, the content of the storage stabilizer is not particularly limited, but for example, 2.0 parts per 100 parts by mass of the total content of the developer (B) and the developer (C). 5 to 100 parts by mass is preferable, and 5 to 50 parts by mass is more preferable.

Examples of the optional components include auxiliary agents. Examples of the auxiliary agent include, but are not limited to, dispersants such as sodium dioctyolsuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, fatty acid metal salts, zinc stearate, calcium stearate, polyethylene wax, Waxes such as carnauba wax, paraffin wax, ester wax, etc., hydrazide compounds such as adipic acid dihydrazide, glyoxal, boric acid, dialdehyde starch, methylol urea, glyoxylate, waterproofing agents such as epoxy compounds, antifoaming agents, coloring Examples include dyes, fluorescent dyes, and pigments.

Examples of the optional component used in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention and the coating material for the heat-sensitive recording layer of the present invention include binders. The binder is not particularly limited, but examples include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, and amide-modified polyvinyl alcohol having a degree of polymerization of 200 to 1900. , sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, ethyl cellulose, cellulose derivatives such as acetyl cellulose, polyvinyl acetate, polyvinyl Acrylamide, polyacrylate, polyvinyl butyral polystyrene and their copolymers, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, chroman resin and the like. These binders may be used singly or in combination of two or more. They may be dissolved in a solvent and used, or may be used in an emulsified or pasty dispersed state in water or other medium.

Examples of the optional component used in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention and the paint for the heat-sensitive recording layer of the present invention include pigments. Examples of the pigment include, but are not limited to, silica, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, zinc oxide, aluminum hydroxide, polystyrene resin, urea-formalin resin, styrene-methacrylic acid copolymer, Examples include inorganic or organic pigments such as styrene-butadiene copolymers and hollow plastic pigments.

The types and amounts of the basic dyes, color developers, sensitizers, binders, pigments and other additives used in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention and the paint for the heat-sensitive recording layer of the present invention are: is not particularly limited, and can be appropriately determined according to the quality performance required for the thermosensitive recording layer, for example.

The method for producing the heat-sensitive recording layer coating material of the present invention is not particularly limited. Except for using C) (N-substituted amino acid derivative represented by the general formula (2)) in combination, it can be produced in the same manner as for general coating materials for heat-sensitive recording layers. Specifically, for example, in addition to a colorless or light-colored basic dye at room temperature and a developer capable of developing color upon contact with the basic dye by heating, a binder, a sensitizer, a filler, a lubricant, Other additives and the like can be added to produce the coating material for the heat-sensitive recording layer of the present invention. The heat-sensitive recording layer coating material of the present invention can also be produced, for example, by the production method described in Examples below.

In the heat-sensitive recording material of the present invention, the method for forming the heat-sensitive recording layer and the method for producing the heat-sensitive recording material are not particularly limited. It may be the same as the method for forming a general heat-sensitive recording layer and the method for producing a heat-sensitive recording material. Specifically, for example, the heat-sensitive recording layer coating material (coating solution) of the present invention produced as described above is applied on a support to form a heat-sensitive recording layer, and the heat-sensitive recording material of the present invention is prepared. can be manufactured. In the heat-sensitive recording material of the present invention, the support is not particularly limited, and may be, for example, at least one of paper and film. That is, the heat-sensitive recording material of the present invention may be, for example, heat-sensitive recording paper whose support is paper. Further, the heat-sensitive recording material of the present invention may be, for example, a heat-sensitive recording film whose support is a film. The paper is not particularly limited, but examples thereof include paper, recycled paper, synthetic paper, and the like. Examples of the film include, but are not limited to, plastic films, non-woven fabrics, and metal foils. Further, the support of the present invention may be made of, for example, a single material, or may be a composite sheet in which a plurality of materials are combined.

The heat-sensitive recording layer in the heat-sensitive recording material of the present invention and the paint for the heat-sensitive recording layer of the present invention preferably contain, for example, 20 to 400 parts by mass of a sensitizer with respect to 100 parts by mass of a basic dye. It preferably contains 5 to 50% by weight of binder per minute.

The heat-sensitive recording material of the present invention may or may not contain optional components other than the support and the heat-sensitive recording layer. For example, as an optional component, an overcoat layer made of a polymeric substance containing an organic pigment may be provided for the purpose of enhancing the storage stability of the heat-sensitive recording layer. Further, for example, an undercoat layer containing organic pigments, inorganic pigments, hollow fine particles, etc. may be provided as the above optional constituent elements for the purpose of preventing dregs from adhering to the thermal head, improving print quality, and improving sensitivity. Also good.

In the present invention, the basic dyes, color developers, sensitizers and, if necessary, storage stabilizers used in the heat-sensitive recording layer or paint for the heat-sensitive recording layer are dispersed in water as a dispersion medium, for example, in a ball mill, attritor, It may be used after being finely dispersed by a stirring pulverizer such as a sand mill so that the average particle size is 2 μm or less.

By mixing and stirring pigments, binders, auxiliaries, and the like, if necessary, into the finely dispersed liquid dispersion, the coating material for the heat-sensitive recording layer can be produced as described above.

Furthermore, the heat-sensitive recording material of the present invention can be produced by applying the heat-sensitive recording layer coating thus obtained onto a support and then drying it to form a heat-sensitive recording layer on the support. can be done. The coating amount of the heat ^- sensitive recording layer coating material on the support is not particularly limited. More preferably 7 g/m ² .

As the support in the heat-sensitive recording material of the present invention, for example, paper, recycled paper, synthetic paper, plastic film, non-woven fabric, metal foil and the like can be used as described above. A composite sheet obtained by combining these can also be used as the support. The thickness of the support is not particularly limited, and can be appropriately adjusted, for example, according to the application of the heat-sensitive recording material of the invention.

According to the present invention, it is possible to provide a heat-sensitive recording material that satisfies the performance requirements as a heat-sensitive recording material, such as color density, whiteness, and wet heat resistance, heat resistance, water resistance, and plasticizer resistance of the printed area. can.

Examples of the present invention are shown below together with comparative examples. However, the present invention is not limited to the following examples. In the following examples, "parts" means "mass parts" unless otherwise specified, and "%" means "% by mass" unless otherwise specified.

In this example, the coating material for the heat-sensitive recording layer and the heat-sensitive recording material were produced as follows.

[Preparation of paint for undercoat layer]
100 parts of plastic hollow particles (trade name: Lopake (registered trademark) SN-1055: hollowness: 55% solid content: 26.5%), 100 parts of calcined kaolin 50% dispersion, styrene-butadiene latex (trade name: L-1571 solid content 48%) 25 parts, 1 of oxidized starch
A paint for the undercoat layer was prepared by mixing 50 parts of a 0% aqueous solution and 20 parts of water. This undercoat layer coating material was used in the production of heat-sensitive recording materials in Examples 1 to 13 and Comparative Examples 1 to 9 below.

(Example 1)
[Production (preparation) of paint for thermal recording layer]
A solution (preparation of basic dye dispersion)
3-(N,N-dibutylamino)-6-methyl-7-anilinofluorane 10 parts 10% polyvinyl alcohol aqueous solution 10 parts water 16.7 parts

B solution (preparation of color developer (B) dispersion)
4,4'-Hydroxydiphenylsulfone 20 parts 10% polyvinyl alcohol aqueous solution 20 parts Water 33.3 parts

C solution (preparation of color developer (C) dispersion)
N-(m-tolylaminocarbonyl)-phenylalanine 20 parts 10% polyvinyl alcohol aqueous solution 20 parts water 33.3 parts

D solution (preparation of sensitizer dispersion)
1,2-bis(3-methylphenoxy)ethane 15 parts 10% polyvinyl alcohol aqueous solution 15 parts water 25 parts

The dispersion liquids of the above liquids A, B, C and D were pulverized with a sand grinder until the average particle size became 1 μm or less, and the dispersion liquids were mixed at the following ratio to prepare a coating liquid.
A solution (basic dye dispersion) 36.7 parts B solution (color developer (B) dispersion) 55.0 parts C solution (color developer (C) dispersion) 18.3 parts D solution (sensitization agent dispersion) 55.0 parts

27 parts of aluminum hydroxide (trade name: Hygilite (registered trademark) H-42), 10 parts of amorphous silica (trade name: Mizukasil (registered trademark) P-605), 10% of oxidized starch A composition consisting of 100 parts of the melt, 19.4 parts of a zinc stearate dispersion (trade name: Hydrin (registered trademark) Z-8-36), and 20 parts of water was mixed to prepare the thermosensitive recording layer of this example. We manufactured (prepared) a paint for

[Production (production) of thermal recording material]
A fine paper (acidic paper) with a basis weight of 53 gm ² was prepared as a support. On the support, the aforementioned paint for undercoat layer was applied and dried so that the weight per area after drying was 6 g/m ² to form an undercoat layer. Thereafter, the above paint for thermosensitive recording layer is applied to the undercoat layer so that the weight per unit area after drying is 3.8 g/m ² , and dried to form a thermosensitive recording layer. A sheet having a coat layer and a heat-sensitive recording layer was obtained. The obtained sheet was treated with a supercalender so that the smoothness was 900 to 1200 seconds to prepare a heat-sensitive recording material. The smoothness was measured by a method according to J1S P8155:2010 "Paper and paperboard-Smoothness test method-Oken method".

[Various tests]
For the heat-sensitive recording material produced (prepared) in this example, the following 1. ~ 5. Various tests were conducted according to the test method of

1. Thermal recording test (color development test)
The heat-sensitive recording material thus prepared was applied with an applied energy of 0.38 mJ/dot using a heat-sensitive recording paper printing tester (TH-PMD manufactured by Okura Denki Co., Ltd.). The print density of the recorded portion was measured with a Macbeth reflection densitometer (trade name: RD-914, manufactured by Glutag Macbeth). This was used as a sample (blank).

2. Humidity and heat resistance test After the thermal recording material recorded in the thermal recording property test was left in an environment of a test temperature of 40°C and 90% RH for 24 hours, the image density of the printed part and the density of the unprinted part of the test piece were measured using a Macbeth reflection densitometer. measured in

3. Heat resistance test After the thermal recording material recorded in the thermal recording property test was left in a constant temperature environment at a test temperature of 60°C for 24 hours, the image density of the printed part and the density of the unprinted part of the test piece were measured with a Macbeth reflection densitometer. .

4. Water resistance test The thermal recording paper recorded in the thermal recording property test was immersed in water for 15 hours, then the test piece was air-dried, and the image density and unprinted area were measured with a Macbeth reflection densitometer.

5. Plasticizer resistance test A plastic wrap film (trade name: Hiwrap (registered trademark) KMA, manufactured by Mitsui Chemicals) was wrapped three times on a polycarbonate pipe (48 mmφ), and the thermosensitive recording paper recorded in the thermosensitive recording test was placed on it. A cling film was wrapped three times over the film and allowed to stand in an environment of 20° C. and 65% RH for 24 hours.

The above 1. for the heat-sensitive recording material of this example. ~ 5. The various test results of were as described in Table 1 below.

(Example 2)
Example 1 was carried out in the same manner as in Example 1 except that 55.0 parts of B solution and 18.3 parts of C solution in Example 1 were changed to 64.1 parts of B solution and 9.2 parts of C solution. 2 and a heat-sensitive recording material of Example 2 were prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Example 2.

(Example 3)
The same operation as in Example 1 was performed except that 55.0 parts of B solution and 18.3 parts of C solution in Example 1 were changed to 69.6 parts of B solution and 3.7 parts of C solution. A heat-sensitive recording layer coating material of Example 3 and a heat-sensitive recording material of Example 3 were prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Example 3.

(Example 4)
Example 1 was carried out in the same manner as in Example 1 except that 55.0 parts of B solution and 18.3 parts of C solution in Example 1 were changed to 36.7 parts of B solution and 36.7 parts of C solution. 4 and a heat-sensitive recording material of Example 4 were prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Example 4.

(Example 5)
Example 5 was prepared in the same manner as in Example 1 except that 55.0 parts of B solution and 18.3 parts of C solution in Example 1 were changed to 18.3 parts of B solution and 55 parts of C solution. Heat-sensitive recording layer paint and Example 5 A heat-sensitive recording material was prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Example 5.

(Example 6)
The same procedure as in Example 1 was carried out except that N-(m-tolylaminocarbonyl)-phenylalanine in solution C of Example 1 was changed to N-(phenylaminocarbonyl)-phenylalanine, and the thermal sensitivity of Example 6 was obtained. Recording Layer Coating Material and Example 6 A heat-sensitive recording material was prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Example 6.

(Example 7)
Thermal recording of Example 7 was carried out in the same manner as in Example 1 except that N-(m-tolylaminocarbonyl)-phenylalanine in solution C of Example 4 was changed to N-(phenylaminocarbonyl)-phenylalanine. Layer Coatings and Example 7 A heat-sensitive recording material was prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Example 7.

(Example 8)
The same procedure as in Example 1 was repeated except that 4,4'-dihydroxydiphenylsulfone in solution B of Example 1 was changed to 2,4-dihydroxydiphenylsulfone to obtain a coating material for a thermosensitive recording layer of Example 8 and an embodiment. Example 8 A heat-sensitive recording material was prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Example 8.

(Example 9)
Example 9 was prepared in the same manner as in Example 1 except that 4,4'-dihydroxydiphenylsulfone in solution B of Example 1 was changed to 4-hydroxy-4'-n-propyloxydiphenylsulfone. Heat-sensitive recording layer coating material and Example 9 A heat-sensitive recording material was prepared.
Table 2 shows various test results of the heat-sensitive recording material according to Example 9.

(Example 10)
Example 10 was prepared in the same manner as in Example 1, except that 4,4'-dihydroxydiphenylsulfone in solution B of Example 1 was changed to 4-hydroxy-4'-1-propyloxydiphenylsulfone. A heat-sensitive recording layer coating material and a heat-sensitive recording material of Example 10 were prepared.
Table 2 shows various test results of the heat-sensitive recording material according to Example 10.

(Example 11)
Thermal recording of Example 11 was carried out in the same manner as in Example 1 except that bis(3-allyl-4-hydroxyphenyl)sulfone was used instead of 4,4'-dihydroxydiphenylsulfone in solution B of Example 1. Layer Coatings and Example 11 A thermosensitive recording material was prepared.
Table 2 shows various test results of the heat-sensitive recording material according to Example 11.

(Example 12)
Thermal recording of Example 12 was carried out in the same manner as in Example 1 except that 4-[(4-allyloxy)phenylsulfonyl]phenol was used instead of 4,4'-dihydroxydiphenylsulfone in solution B of Example 1. Layer Coatings and Example 12 A heat-sensitive recording material was prepared.
Table 2 shows various test results of the heat-sensitive recording material according to Example 12.

(Example 13)
A thermosensitive recording layer of Example 13 was prepared in the same manner as in Example 1, except that 4,4'-dihydroxydiphenylsulfone in solution B of Example 1 was changed to 4-benzyloxy-4'-hydroxydiphenylsulfone. A heat-sensitive recording material for Example 13 was prepared.
Table 2 shows various test results of the heat-sensitive recording material according to Example 13.

[Comparative Example 1]
The same operation as in Example 1 was performed except that 55.0 parts of B liquid and 18.3 parts of C liquid in Example 1 were changed to 73.3 parts of B liquid, and C liquid was not used. A heat-sensitive recording layer coating material of Example 1 and a heat-sensitive recording material of Comparative Example 1 were prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Comparative Example 1.

[Comparative Example 2]
The same operation as in Example 1 was performed except that 55.0 parts of B liquid and 18.3 parts of C liquid in Example 1 were changed to 73.3 parts of C liquid, and B liquid was not used. A heat-sensitive recording layer coating material of Example 2 and a heat-sensitive recording material of Comparative Example 2 were prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Comparative Example 2.

[Comparative Example 3] The same procedure as in Comparative Example 2 was carried out, except that N-(m-tolylaminocarbonyl)-phenylalanine in solution C was changed to N-(phenylaminocarbonyl)-phenylalanine. A heat-sensitive recording layer coating material of Comparative Example 3 and a heat-sensitive recording material of Comparative Example 3 were prepared.
Table 1 shows various test results of the heat-sensitive recording material according to Comparative Example 3.

[Comparative Example 4] The same procedure as in Example 8 was carried out except that 55.0 parts of B liquid and 18.3 parts of C liquid in Example 8 were changed to 73.3 parts of B liquid, and C liquid was not used. A heat-sensitive recording layer coating material of Comparative Example 4 and a heat-sensitive recording material of Comparative Example 4 were prepared by carrying out the operations.
Table 2 shows various test results of the thermal recording material according to Comparative Example 4.

[Comparative Example 5] The same procedure as in Example 9 was carried out except that 55.0 parts of B liquid and 18.3 parts of C liquid in Example 9 were changed to 73.3 parts of B liquid, and C liquid was not used. A heat-sensitive recording layer coating material of Comparative Example 5 and a heat-sensitive recording material of Comparative Example 5 were prepared by carrying out the operations.
Table 2 shows various test results of the heat-sensitive recording material according to Comparative Example 5.

[Comparative Example 6] The same procedure as in Example 10 was performed except that 55.0 parts of B liquid and 18.3 parts of C liquid in Example 10 were changed to 73.3 parts of B liquid, and C liquid was not used. A heat-sensitive recording layer coating material of Comparative Example 6 and a heat-sensitive recording material of Comparative Example 6 were prepared by carrying out the operations.
Table 2 shows various test results of the heat-sensitive recording material according to Comparative Example 6.

[Comparative Example 7] The same procedure as in Example 11 was performed except that the 55.0 parts of B liquid and 18.3 parts of C liquid in Example 11 were changed to 73.3 parts of B liquid, and C liquid was not used. A heat-sensitive recording layer coating material of Comparative Example 7 and a heat-sensitive recording material of Comparative Example 7 were prepared by carrying out the operations.
Table 2 shows various test results of the thermal recording material according to Comparative Example 7.

[Comparative Example 8] The same procedure as in Example 12 was carried out except that 55.0 parts of B liquid and 18.3 parts of C liquid in Example 12 were changed to 73.3 parts of B liquid, and C liquid was not used. A heat-sensitive recording layer coating material of Comparative Example 8 and a heat-sensitive recording material of Comparative Example 8 were prepared by the operation.
Table 2 shows various test results of the heat-sensitive recording material according to Comparative Example 8.

[Comparative Example 9] The same procedure as in Example 13 was performed except that 55.0 parts of B liquid and 18.3 parts of C liquid in Example 13 were changed to 73.3 parts of B liquid, and C liquid was not used. A heat-sensitive recording layer coating material of Comparative Example 9 and a heat-sensitive recording material of Comparative Example 9 were prepared by carrying out the operations.
Table 2 shows various test results of the heat-sensitive recording material according to Comparative Example 9.

The heat-sensitive recording materials of Examples 1 to 7 contain 4,4'-dihydroxydiphenylsulfone, which is one of the 4-hydroxydiphenylsulfone derivatives represented by the general formula (1), as the color developer (B), and , a heat-sensitive recording material comprising a support and a heat-sensitive recording layer containing a developer containing an N-substituted amino acid derivative represented by the general formula (2) as a developer (C). The heat-sensitive recording materials of Examples 1 to 7 contain the color developer (B) alone while maintaining the properties of the heat-sensitive recording material in which the heat-sensitive recording layer containing the color developer (B) is provided on the support. The plasticizer resistance was superior to that of the heat-sensitive recording material (Comparative Example 1) in which a heat-sensitive recording layer was provided on the support. Furthermore, the heat-sensitive recording materials of Examples 1 to 7 are more resistant to plasticizers than the heat-sensitive recording materials (Comparative Examples 2-3) in which a heat-sensitive recording layer containing the color developer (C) alone is provided on the support. was excellent.

The heat-sensitive recording materials of Examples 8 to 13 contained a 4-hydroxydiphenylsulfone derivative represented by the general formula (1) as the developer (B), and a developer (C) represented by the general formula ( 2), which is a heat-sensitive recording material comprising a support and a heat-sensitive recording layer containing N-(m-triaminocarbonyl)-phenylalanine, which is one of the N-substituted amino acid derivatives represented by formula 2). The heat-sensitive recording materials of Examples 8 to 13 contain the developer (B) alone while maintaining the properties of the heat-sensitive recording material in which the heat-sensitive recording layer containing the developer (B) is provided on the support. The plasticizer resistance was superior to the heat-sensitive recording materials (Comparative Examples 4 to 9) in which a heat-sensitive recording layer was provided on the support.

As described above, according to the present invention, it is possible to provide a color developer, a heat-sensitive recording material, and a heat-sensitive recording layer coating material which are excellent in plasticizer resistance. According to the color developer, heat-sensitive recording material and heat-sensitive recording layer coating material of the present invention, for example, the color density, whiteness and various good storage properties of the compound represented by the general formula (1) are reduced. It is also possible to further improve the plasticizer resistance without Applications of the color developer, heat-sensitive recording material, and heat-sensitive recording layer coating material of the present invention are not particularly limited, and, for example, they can be widely used in the same applications as common color developers, heat-sensitive recording materials, and heat-sensitive recording layer coating materials. , and the industrial applicability is enormous.

Claims (9)

A developer for a thermosensitive recording layer,
A color developer comprising a 4-hydroxydiphenylsulfone derivative represented by the following general formula (1) and an N-substituted amino acid derivative represented by the following general formula (2).

In the general formula (1),
R ¹ and R ² each represent a hydrogen atom, a C1-C8 alkyl group, a C1-C8 alkoxy group, a C7-C11 aralkyl group, or an allyl group;
R ³ represents a hydrogen atom, a C1-C8 alkyl group, a C7-C11 aralkyl group, or an allyl group;
R ¹ , R ² and R ³ may be the same or different,
When R ¹ is plural, each R ¹ may be the same or different,
When R ² is plural, each R ² may be the same or different,
When R ³ is plural, each R ³ may be the same or different.

(R ⁰ -X)-Y-(Z) (2)

In the general formula (2),
R ⁰ is an alkyl group having a C6-C10 aryl group, or has a substituent of a C1-C8 alkyl group, a C7-C11 aralkyl group, a C6-C10 aryl group, or a C1-C8 alkoxy group; represents an aryl group that may be
X is a group that binds to the N-terminus of Y and represents -OCO-, -SO _{2 NHCO-, -NHCO-, -NHCS- or -SO 2 -} ;
Y represents an amino acid residue or a peptide residue, and the OH group of a serine residue, a threonine residue, an aspartic acid residue, a glutamic acid residue, or a tyrosine residue in the Y group is an OR ⁰ group or an OR" The SH group of the cysteine residue may be substituted with an SR ⁰ group or an SR″ group, and the NH group of the histidine residue may be substituted with an NR ⁰ group or an NR′ group. the _NH2 group of a lysine residue or an ornithine residue may be substituted with an NHR ⁰ group or an NHR' group, where R' represents an amino protecting group and R" represents a carboxy protecting group. ,
provided that Y is an amino acid residue other than a cystine residue, or a peptide residue that does not have a cystine residue,
Z is a group that binds to the C-terminal of Y and represents an OH group or an OR″ group;
A plurality of R ⁰ , R′ and R″ may be the same or different,
When R ⁰ is plural, each R ⁰ may be the same or different,
When there are multiple R', each R' may be the same or different,
When R" is plural, each R" may be the same or different,
Two or more groups of R ⁰ , R′ and R″ may combine with each other to form a ring. The 4-hydroxydiphenyl sulfone derivative is 4,4'-dihydroxydiphenyl sulfone, 2,4-dihydroxydiphenyl sulfone, 4-hydroxy-4'-i-propoxydiphenyl sulfone, 4-hydroxy-4'-n-propoxydiphenyl Sulfone, 4-hydroxy-4'-benzyloxydiphenylsulfone, bis(3-allyl-4-hydroxyphenyl)sulfone, 4-[(4-allyloxy)phenylsulfonyl]phenol and 4-benzyloxy-4'-hydroxydiphenyl 2. The developer according to claim 1, which is at least one selected from sulfones. wherein said N-substituted amino acid derivative represented by general formula (2) is at least one selected from N-(m-tolylaminocarbonyl)-phenylalanine and N-(phenylaminocarbonyl)-phenylalanine; 3. The color developer according to 1 or 2. The content of the N-substituted amino acid derivative represented by the general formula (2) is 1 part by mass or more with respect to 100 parts by mass of the 4-hydroxydiphenylsulfone derivative represented by the general formula (1). The color developer according to any one of claims 1-3. A thermosensitive recording material having a thermosensitive recording layer on a support,
The thermosensitive recording layer contains a colorless or light-colored basic dye at room temperature and a developer capable of developing color upon contact with the basic dye by heating,
A heat-sensitive recording material, wherein the developer is the developer according to any one of claims 1 to 4. 6. The thermal recording material according to claim 5, wherein said support is at least one of paper and film. A heat-sensitive recording layer coating for use in forming a heat-sensitive recording layer,
Containing a colorless or light-colored basic dye at room temperature and a developer capable of developing color upon contact with the basic dye upon heating,
A paint for a heat-sensitive recording layer, wherein the developer is the developer according to any one of claims 1 to 4. The content of the N-substituted amino acid derivative represented by the general formula (2) is 1 part by mass or more with respect to 100 parts by mass of the 4-hydroxydiphenylsulfone derivative represented by the general formula (1). The coating material for a heat-sensitive recording layer according to claim 7. 9. The heat-sensitive recording layer coating material according to claim 7, which is used for forming the heat-sensitive recording layer in the heat-sensitive recording material according to claim 5 or 6.