JP2018144392A - Heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive recording material that satisfies the required performance as a developer.SOLUTION: Provided is a heat-sensitive recording material having on a support a heat-sensitive recording layer containing a basic dye of colorless or pale color at room temperature and a developer capable of color development upon contact with the dye by heating, and in which, as the developer, at least one N-substituted amino acid derivative represented by the general formula (1) (R-X)-Y-(Z)is contained and N-p-toluenesulfonyl N'-3-(p-toluenesulfonyl-oxy) phenylurea is contained. (In the formula (1), R represents an alkyl group which may have a substituent, or an aryl group; X is a group bonding to the N terminus of Y and represents -OCO-, -SONHCO-, -NHCO-, -NHCS-, or -SO; Z is a group bonding to the C-terminus of Y and represents an OH group or OR" group; and Y is an amino acid residue other than a cystine residue or a peptide residue not having a cystine residue, and m=1.).SELECTED DRAWING: None

Description

  The present invention relates to a heat-sensitive recording material. Specifically, an N-substituted amino acid derivative is used as a developer, and Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea is used together with the developer. The present invention relates to a heat-sensitive recording material having improved water resistance.

  In general, a heat-sensitive recording material is a color-sensitive recording material obtained by adding a colorless or light-colored basic dye and an organic developer at room temperature to heat energy (diure heat) of a heat-sensitive head, heat pen, etc. Has already been widely put into practical use.

The performance required for the heat-sensitive recording material includes the whiteness of the unprinted portion, the whiteness of the unprinted portion under various environmental conditions, the color density of the printed portion, and the storage stability of the printed portion.
The storage stability of the printed part means the performance that does not disappear when the printed image is placed in a high humidity environment, when water adheres, when oils adhere, or when a plasticizer adheres. To do.

  On the other hand, the required performance of printing formed by a heat-sensitive recording material largely depends on dyes, developers, and sensitizers that are the main components of the heat-sensitive recording material, and is particularly affected by the developer. For this reason, synthetic compounds derived from petrochemicals such as phenolic compounds and sulfonylurea compounds have been proposed as color developers that satisfy the above required performance. Among them, many phenolic compounds have been developed and put into practical use.

  However, some phenolic compounds are suspected of endocrine disrupting substances and their use tends to be suppressed. For example, bisphenol A (2,2-bis (4-hydroxyphenyl) propane) has been used in large quantities as a raw material for polyesters and as a color developer for thermal paper. Are regulated as second and third monitoring chemical substances in the revised law, and as a priority evaluation chemical substance in the revised law, and their use is suspected of endocrine disrupting substances in the EU, the United States, Canada, Japan The country has already been refraining.

  Bisphenol S (4,4'-dihydroxydiphenylsulfone) is registered as a designated chemical substance and regulated as a second monitoring chemical substance in the law regarding the examination and manufacturing regulations of chemical substances before revision due to suspicion such as chromosomal abnormalities. It had been.

  There is a proposal that a synthetic compound such as 4,4'-diaminodiphenylalkane is used as a raw material as a non-phenolic developer such as a sulfonylurea compound (Patent Document 1). The use of a non-phenolic color developer using an acylated amino acid mainly composed of a natural amino acid has also been proposed (Patent Document 2). In addition, a heat-sensitive recording material that obtains an image by applying a browning reaction (Maillard reaction) by heating amino acids and saccharides has been proposed (Patent Document 3).

JP 05-147357 A Japanese Patent Laid-Open No. 07-109423 JP 2005-254664 A

  However, the sulfonylurea compound proposed in Patent Document 1 has problems such as using as a raw material a synthetic compound having a molecular structure similar to bisphenol A as a constituent component, and a demand as a color developer for a thermal recording material. It was not enough for performance.

  Although the use of a developer using an acylated amino acid made of a natural amino acid as the main raw material in Patent Document 2 is not within the category of the causative substances of endocrine disruption described above, In various storage stability of the printing unit and the printing unit, the quality performance does not reach the required performance as a developer of the heat-sensitive recording material.

  The proposal for obtaining an image by applying the browning reaction (Maillard reaction) by heating amino acids and sugars in Patent Document 3 does not satisfy the required performance as a developer.

  The present invention has been made in view of the above circumstances, and an N-substituted amino acid derivative having no concern about color density, whiteness, and endocrine disrupting action has been developed in order to improve the water resistance of the printed portion. A thermosensitive recording material using toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea is provided.

  The present inventors have studied from the viewpoint of whether amino acids that are also foods can be used as developers of heat-sensitive recording materials. As a result, it was found that amino acids do not develop color even when they come into contact with basic dyes, because basic amino groups and acidic carboxyl groups coexist in the same molecule and neutralize in the molecule. By introducing a functional group that contributes to the required performance and color developing ability of a heat-sensitive recording material as a protective group for the amino group of the amino acid, the present inventors have eliminated intramolecular neutralization, and In particular, the present inventors have completed an invention relating to a heat-sensitive recording material in which an N-substituted amino acid derivative using a natural amino acid as a raw material is used as a developer (Japanese Patent Application No. 2006-140814).

  The present inventors have further improved the storage stability of the printed part, in particular water resistance, without lowering the color density, whiteness, and heat resistance of the heat-sensitive recording material using the N-substituted amino acid derivative as a developer. To provide an excellent thermal recording material. As a result, when the N-substituted amino acid derivative was used as a developer, Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea was used in combination, whereby the N-substituted amino acid was used. It was found that the storage stability of the printed part, in particular water resistance, was further improved without lowering the color density, whiteness and heat resistance of the heat-sensitive recording material using the derivative as a developer, and the present invention was completed. It was.

The present invention relates to a heat-sensitive recording material provided with a heat-sensitive recording layer on a support, which contains a colorless or light-colored basic dye at room temperature and a color developer that can be brought into contact with the dye by heating. And at least one N-substituted amino acid derivative represented by the following general formula (1) as the developer, and Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea The present invention relates to a heat-sensitive recording material.
(R-X) _m -Y- (Z) _m (1)
(In Formula (1), R 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 alkoxy group. Represents an aryl group which may have a substituent.
X is a group attached to the N-terminus of _{Y, -OCO -, - SO 2} NHCO -, - NHCO -, - NHCS-, or -SO ₂ - represent.
Y represents an amino acid residue or a peptide residue, and an 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 group or an OR ″ group. The SH group of the cysteine residue may be substituted with the SR group or the SR ″ group, and the NH group of the histidine residue may be substituted with the NR group or the NR ′ group. Well, the NH ₂ group of the lysine residue or ornithine residue may be substituted with an NHR group or an NHR ′ group, R ′ represents an amino protecting group and R ″ represents a carboxy protecting group.
Z is a group bonded to the C terminus of Y and represents an OH group or an OR ″ group.
A plurality of R, R ′, and R ″ may be the same or different, and may be bonded to each other to form a ring.
However, Y is a peptide residue which is an amino acid residue other than a cystine residue or does not have a cystine residue, and m = 1. )

  The developer is N- (m-tolylaminocarbonyl) -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 preferable.

  The derivative developer using the N-substituted amino acid as a raw material constituting the present invention satisfies the required performance of a heat-sensitive recording material equivalent to that of a conventional developer, and is a safe heat-sensitive substance having no endocrine disrupting action or the like. Further, it is possible to provide a heat-sensitive recording material that is a recording material and has high storage stability, particularly water resistance, without reducing the color density, whiteness, and heat resistance of the heat-sensitive recording material.

  The heat-sensitive recording material of the present invention comprises a colorless or light-colored basic dye at room temperature, a developer that can be brought into contact with the dye by heating, and Np-toluenesulfonyl N′-3- (p- A heat-sensitive recording material comprising a heat-sensitive recording layer containing toluenesulfonyloxy) phenylurea on a support.

  The heat-sensitive recording material of the present invention is a heat-sensitive recording provided on a support with a heat-sensitive recording layer containing a colorless or light-colored basic dye at room temperature and a color developer that can be brought into contact with the dye by heating. A material comprising at least one N-substituted amino acid derivative represented by the following general formula (1) as the developer, and Np-toluenesulfonyl N′-3- (p-toluenesulfonyl) Oxy) phenylurea is included. The heat-sensitive recording layer of the heat-sensitive recording material of the present invention comprises the basic dye, the developer represented by the general formula, Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea, Prepare a coating solution obtained by adding binders, sensitizers, fillers, lubricants, and other additives, and apply them to a support such as paper, plastic film, or processed paper. Is done.

In the heat-sensitive recording material of the present invention, the developer is at least one of N-substituted amino acid derivatives represented by the following general formula (1).
(R-X) _m -Y- (Z) _m (1)

  In the formula (1), R 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 alkoxy group. The aryl group which may have a substituent is represented. 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. Can be mentioned. As an aryl group which may have a substituent of a C1-C8 alkyl group, 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 And 3-pentylphenyl group. Examples of the aryl group optionally having a substituent of a C7 to C11 aralkyl group include a p-benzylbiphenyl group. Examples of the aryl group which may have a substituent of the C6-C10 aryl group include a biphenyl group and a 3,3′-dimethylbiphenyl group. Examples of the aryl group which may have a substituent of the C1-C8 alkoxy group include a 6-methoxyphenyl group.

X is a group attached to the N-terminus of _{Y, -OCO -, - SO 2} NHCO -, - NHCO -, - NHCS-, or -SO ₂ - represents a (sulfonyl group).

Y represents an amino acid residue or a peptide residue, and an 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 group or an OR ″ group. The SH group of the cysteine residue may be substituted with the SR group or the SR ″ group, and the NH group of the histidine residue may be substituted with the NR group or the NR ′ group. Well, the NH ₂ group of the lysine residue or ornithine residue may be substituted with an NHR group or an NHR ′ group, R ′ represents an amino protecting group, and R ″ represents a carboxy protecting group. As an amino protecting group (R ′ group) for protecting the NH group of the histidine residue or the NH ₂ group of the lysine residue or the ornithine residue, an RX group can be mentioned. In addition, an acyl group and an alkyl group can be used. Aspartic acid residues in the Y group As carboxy protecting groups for protecting the glutamic acid residue (R "group), an alkoxy group, an aryloxy group, an amino group, an alkylamino group, and an arylamino group. Examples of the protecting group for the OH group of the serine residue, threonine residue, or tyrosine residue in the Y group, or the SH group of the cysteine residue include the carboxy protecting group (R ″ group).

Z is a group bonded to the C terminus of Y and represents an OH group or an OR ″ group.
A plurality of R, R ′, and R ″ may be the same or different, and may be bonded to each other to form a ring.
However, Y is a peptide residue which is an amino acid residue other than a cystine residue or does not have a cystine residue, and m = 1.

  The N-substituted amino acid derivative represented by the above general formula can be easily produced from an amino acid or an amino acid derivative and a sulfonic acid chloride or an isocyanate compound by applying a known method such as the Schotten-Baumann reaction.

  The amino acids, peptides and esters and amides used as the constituent components of the compound represented by the above general formula may be L-form, D-form or DL-form. It may be a natural amino acid, a non-natural amino acid, an α-amino acid, or a β-amino acid. Esters are C1-C4 alkyl esters, aryl esters, aralkyl esters, and amides are amides, alkyl-substituted amides, aryl-substituted amides, and the like.

  Specifically, ester derivatives such as glycine, glycine methyl ester, glycine ethyl ester, glycine-t-butyl ester, glycine phenyl ester, glycine p-cresyl ester, glycine m-cresyl ester, glycine benzyl ester, glycine amide, N Amide derivatives such as' -methylglycinamide, glycylanilide, phenylglycine, phenylglycine methyl ester, phenylglycine ethyl ester, ester derivatives such as phenylglycine benzyl ester, phenylglycinamide, alanine, alanine methyl ester, alanine ethyl ester, Ester derivatives such as alanine benzyl ester, alaninamide, phenylalanine, naphthylalanine, phenylalanine methyl ester, phenyl Ester derivatives such as alanine ethyl ester, phenylalanine benzyl ester, amide derivatives such as phenylalanine amide, N′-methylphenylalanine amide, phenylalanylanilide, valine, valine methyl ester, valine methyl ester, valine isopropyl ester, valine-t-butyl Esters, ester derivatives such as valine benzyl ester, valine amide, leucine, leucine methyl ester, isoleucine, serine, o-methyl serine, o-benzyl serine and other o-substituted serine, serine methyl ester, serine benzyl ester and other ester derivatives, threonine O-substituted threonine such as o-methylthreonine and o-benzylthreonine, threonine methyl ester, threonine-t-butyl ester Ester derivatives such as tyrosine, o-methoxytyrosine, o-benzyloxytyrosine, o-substituted tyrosine such as tyrosine, 3- (3 ′, 4′-dihydroxyphenyl) alanine (DOPA), tyrosine methyl ester, tyrosine benzyl ester Ester derivatives such as tyrosine amide, proline, hydroxyproline, proline methyl ester, proline-t-butyl ester, proline benzyl ester, proline amide, lysine, ornithine, lysine methyl ester, lysine ethyl ester, lysine benzyl ester Ester derivatives such as ornithine methyl ester, ornithine ethyl ester, ornithine benzyl ester, arginine, arginine methyl ester, arginine ethyl ester, histidine Histidine methyl ester, tryptophan, tryptophan methyl ester, tryptophan benzyl ester, tryptophan amide, cysteine, cystine, S-methylcysteine, S-ethylcysteine, S-benzylcysteine, S-phenylcysteine, S-substituted cysteine, cysteine methyl Esters, ester derivatives such as cysteine benzyl ester, S-oxidized derivatives such as cysteine sulfoxide and sulfone, S-oxidized derivatives such as methionine, methionine sulfoxide, methionine sulfone, ester derivatives such as methionine methyl ester, methionine benzyl ester, methionine amide, Aspartic acid, aspartic acid methyl ester, aspartic acid ethyl ester, aspartic acid benzyl ester Ester derivatives such as ether, 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. Further, C1-C8 aminocarboxylic acids such as β-alanine, 5-aminovaleric acid and 7-aminoheptanoic acid are also selected.

  Peptides are glycylglycine, glycylglycine methyl ester, glycylglycinamide, glycylalanine, glycylalanine methyl ester, glycylvaline, glycylleucine, glycylphenylalanine, glycylphenylalanine methyl ester, glycylphenylalaninamide, glycyl Examples include proline, alanylalanine, alanylproline, alanylmethionine, alanylmethionine methyl ester, alanylphenylalanine, glycylglycylglycine and the like.

  The compound represented by the above general formula is an amino group-protected amino acid, peptide or derivative thereof, and the protecting group is widely used in the field of amino acid chemistry or peptide synthesis chemistry.

  As the functional group (—XNH— group) formed by the N-substituent of the N-substituted amino acid derivative represented by the general formula (1) in the thermosensitive recording material of the present invention, a sulfonylamino group, a urethane group, ( (Thio) urea group (ureido), sulfonylurea group, and the like. For example, the sulfonylamino group is derived from arylsulfonyl chloride. The urethane group is derived from a chloroformate such as benzyl chloroformate or a carbonate such as diphenyl carbonate. (Thio) urea groups are derived from iso (thio) cyanate esters such as phenyl iso (thio) cyanate. The sulfonylurea is derived from a sulfonylurea such as toluenesulfonyl isocyanate.

  Specifically, as the compound (X1) forming a sulfonylamino group, benzenesulfonyl chloride, p-toluenesulfonyl chloride, m-toluenesulfonyl chloride, o-toluenesulfonyl chloride, p-methoxybenzenesulfonyl chloride, p- Examples thereof include chlorides such as xylenesulfonyl, m-xylenesulfonyl chloride, mesitylenesulfonyl chloride, 1-naphthalenesulfonyl chloride, and 2-naphthalenesulfonyl chloride, bromides, and iodides.

  Examples of the compound (X2) forming a urethane group include halogenated formic acid esters such as chloroformic acid benzyl ester and chloroformic acid phenyl ester, and carbonic acid esters such as diphenyl carbonate and dibenzyl carbonate.

  As the compound (X3) forming a (thio) urea group, benzyl isocyanate, phenyl isocyanate, p-tolyl isocyanate, m-tolyl isocyanate, o-tolyl isocyanate, 1-naphthyl isocyanate, 2-naphthyl isocyanate, phenylene 1,4 -Diisocyanate, phenylene 1,3-diisocyanate, tolylene 2,4-diisocyanate, tolylene-2,6-diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, naphthalene 1,5-diisocyanate, 4,4 ' -Diisocyanate-3,3'-dimethylbiphenyl, methylenediphenyl-4,4'-diisocyanate, 4,4'-diisocyanate-3,3'-dimethyldiphenylmethane, phenyl isothiocyanate , M- tolyl isothiocyanate, etc. p- tolyl isothiocyanate.

  Examples of the compound (X4) that forms a sulfonylurea group include benzenesulfonyl isocyanate and p-toluenesulfonyl isocyanate.

  Examples of the N-substituted amino acid derivative obtained using the compound (X1) that forms a sulfonylamino group in the general formula (1) 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-toluenesulfonyl) -alanine, N- (p-toluenesulfonyl) -β-alanine, N- (p-toluenesulfonyl) -phenylalanine, N- (p-toluenesulfonyl) -phenylalanine methyl ester, N- (p-toluenesulfonyl) -phenylalanine benzyl ester, N- (p-Torr Sulfonyl) -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 (pt-butylbenzenesulfonyl) -lysine, N-arylsulfonyl-amino acids, esters and amides such as N, N′-di (pt-butylbenzenesulfonyl) -ornithine, N- (1-naphthalenesulfonyl) -tryptophan, N-2-naphthalenesulfonyl-asparagine, N-benzylsulfonyl-valine, N-benzylsulfonyl-tylo Emissions, N- benzylsulfonyl - N- aralkyl sulphonyl including phenylglycine - amino acids, esters and amides.

Examples of the N-substituted amino acid derivative obtained by using the compound (X3) that forms a urea group in the general formula (1) include N-phenylaminocarbonyl-glycine and N-phenylaminocarbonyl-glycine-methyl. Ester, N-phenylaminocarbonyl-glycine benzyl 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 (phenylamino) Cal Bonyl) -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) -glycylglycine, N- ( p-Tolylaminocarbonyl) -glycylglycylglyc 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- (m-tolylaminocarbonyl) -methionine, N- (m-tolylaminocarbonyl) -valine, N- (m-tolylaminocarbonyl) -phenylglycine, N- (m-phenylglycine, N- (3- It is preferable to use at least one selected from the group consisting of isopropenyl-α, α-dimethylbenzyl) aminocarbonyl-methionine, and N- (m-tolylaminocarbonyl) -tyrosine.

  N- (m-tolylaminocarbonyl) -phenylalanine-methyl ester, N- (m-tolylaminocarbonyl) -phenylalanine-ethyl ester, N- (m-tolylaminocarbonyl) -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-tolylenebis (N -Aminocarbonyl-phenylglycine) and the like.

  Examples of the N-substituted amino acid derivative obtained by using the compound (X3) that forms a thiourea group in the general formula (1) 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-phenylaminothiocarbonyl-glycyl Glycine, N-phenylaminothiocarbonyl-glycylalanine, Nm-tolylaminothiocarbonyl-phenylalanine, Nm-tolylaminothiocarbonyl-phenylalanine-benzyl ester, Nm-tolylami Thiocarbonyl-phenylalaninamide, Nm-tolylaminothiocarbonyl-valine, Nm-tolylaminothiocarbonyl-valine-isopropyl ester, Nm-tolylaminothiocarbonyl-methionine-methyl ester, Nm-tolyl Aminothiocarbonyl-glycylglycine, Np-tolylaminothiocarbonyl-phenylalanine, Np-tolylaminothiocarbonyl-phenylalanine-benzyl ester, Np-tolylaminothiocarbonyl-phenylalaninamide, Np-tolyl Aminothiocarbonyl-valine, Np-tolylaminothiocarbonyl-valine-isopropyl ester, Np-tolylaminothiocarbonyl-methionine-methyl ester, Np-tolylaminothiocarbonyl- Rishirugurishin, and the like.

  Examples of the N-substituted amino acid derivative obtained by using the compound (X2) that forms a urethane group in the general formula (1) include N-benzyloxycarbonyl-glycine, N-benzyloxycarbonyl-phenylglycine, N-benzyloxycarbonyl-valine, N-benzyloxycarbonyl-methionine, N-benzyloxycarbonyl-tyrosine, N-benzyloxycarbonyl-hydroxyproline, N-benzyloxycarbonyl-arginine, N-benzyloxycarbonyl-glycine, etc. Can be mentioned.

  Examples of the N-substituted amino acid derivative obtained by using the compound (X4) that forms a sulfonylurea group in the general formula (1) include N- (p-toluenesulfonylaminocarbonyl) -glycine, N- ( p-toluenesulfonylaminocarbonyl) -phenylalanine, N- (p-toluenesulfonylaminocarbonyl) -phenylalanine-methyl ester, N- (p-toluenesulfonylaminocarbonyl) -phenylalanine-ethyl ester, N- (p-toluenesulfonylamino) Carbonyl) -phenylalaninamide, N- (p-toluenesulfonylaminocarbonyl) -β-alanine, N- (p-toluenesulfonylaminocarbonyl) -β-alanine-methyl ester, N- (p-toluenesulfonylaminocarbonyl)- Me Thionine-methyl ester, N- (p-toluenesulfonylaminocarbonyl) -leucine, N, N′-di (p-toluenesulfonylaminocarbonyl) -lysine-methyl ester, N, N′-di (p-toluenesulfonylamino) And carbonyl) -ornithine-methyl ester.

In the heat-sensitive recording material of the present invention, the NH group of the histidine residue or the NH ₂ group of the lysine residue or the ornithine residue in the Y group of the N-substituted amino acid derivative represented by the general formula (1) is protected. Examples of the amino protecting group (R ′ group) include an RX group, and an acyl group and an alkyl group. These amino protecting groups (R ′ groups) can be introduced by a known method. For example, acyl groups can be introduced using acid anhydrides. The alkyl group can be introduced by an alkyl halide such as trityl chloride in the presence of an amine or the like.
As the carboxy protecting group (R ″ group) 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 (1) in the heat-sensitive recording material of the present invention, alkoxy Group, aryloxy group, amino group, alkylamino group, arylamino group, etc. In addition, OH group of serine residue, threonine residue or tyrosine residue in Y group, or SH group of cysteine residue Examples of the protecting group include the carboxy protecting group (R ″ group). These carboxy protecting groups (R ″ groups) can be introduced by a known method.

Preferred N-substituted amino acid derivatives as developers in the heat-sensitive recording material of the present invention include N- (p-toluenesulfonyl) -glycine, N- (p-toluenesulfonyl) -alanine, and N- (p-toluenesulfonyl). N-allylsulfonyl-amino acids such as β-alanine, N-phenylaminocarbonyl-glycine, N-phenylaminocarbonyl-valine, N- (m-tolylaminocarbonyl) -phenylalanine, N- (m-tolylaminocarbonyl) Cysteine-S-benzyl, N- (m-tolylaminocarbonyl) -methionine, N- (m-tolylaminocarbonyl) -tyrosine, N- (p-tolylaminocarbonyl) -phenylalanine, N- (p-tolylamino) Carbonyl) -cysteine-S-benzyl, N- (p-tolyl) N-aminocarbonyl-amino acids such as minocarbonyl) -methionine, N- (p-tolylaminocarbonyl) -methionine, N- (phenylaminocarbonyl) -methionine, N- (p-tolylaminocarbonyl) -tyrosine, Particularly preferably, N- (m-tolylaminocarbonyl) -phenylalanine, N- (m-tolylaminocarbonyl) -methionine, N- (p-tolylaminocarbonyl) -methionine, N- (phenylaminocarbonyl) -methionine, Mention may be made of N- (m-tolylaminocarbonyl) -valine, N- (m-tolylaminocarbonyl) -phenylglycine and N- (m-tolylaminocarbonyl) -tyrosine.
One or more of these N-substituted amino acid derivatives may be used in combination.

  Furthermore, Z is preferably an OH group, and X is preferably an —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- (m-tolylamino) It is preferable to use at least one selected from the group consisting of (carbonyl) -phenylglycine and N- (m-tolylaminocarbonyl) -tyrosine.

  In this invention, you may use together with the existing color developer in the range which does not inhibit the effect of this invention.

  In the present invention, Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea is used together with the N-substituted amino acid derivative without reducing the color density and whiteness of the thermosensitive recording material. The background heat resistance can be maintained, and the storage stability of the printed portion, particularly the water resistance can be further improved.

The content of Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea is preferably 10 to 400 parts by mass with respect to 100 parts by mass of the developer represented by the general formula (1). 20-200 mass parts is more preferable.
In the heat-sensitive recording material of the present invention, triphenylmethane, fluorane, diphenylmethane, spiro, fluorene, and thiazine compounds can be used as colorless or light-colored basic dyes at room temperature, and selected from conventionally known leuco dyes Can do.
For example, 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-methylindole-3-yl) -3- (4-diethylamino-2-n-hexyloxyphenyl-4-azaphthalide, 3- (1-ethyl-2-methylindole-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 Fluoran,

3- (N-ethyl-Np-toluidino) -6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-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-ethylamino] 6- Methyl-7-anilinofluorane, 3- (Nn-hexyl-N-ethylamino) -7- (o-chloroanilino) fluorane, 3- (N-ethyl-N-2-tetrahydride) Furfurylamino) -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-chloroanilino) 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-phenoxyfluorane, 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-ani Linofluorane, 3-diethylamino-7-benzylaminofluorane, 3-pyrrolidino-7-dibenzylaminofluorane and the like can be selected. The present invention is not limited to these, and two or more types can be selected. May be used in combination.

A conventionally known sensitizer can be used in combination as the sensitizer of the present invention.
For example, fatty acid amides such as stearic acid amide, bis stearic acid amide, and palmitic acid amide, p-toluenesulfonamide, stearic acid, calcium such as behenic acid and palmitic acid, fatty acid metal salts such as zinc and aluminum, p-benzylbiphenyl , Diphenylsulfone, benzyloxybenzyl benzoate, 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.

Further, in the present invention, conventionally known storage stabilizers can be used in combination.
For example, 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-butyl m-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-hydroxy Benzyl) isocyanurate, 4,4′-thiobis (3-methylphenol), 4,4′-dihydroxy-3,3 ′, 5,5′-tetrabromodiphenylsulfone, 4,4′-dihydroxy 3,3 ′ , 5,5'-tetramethyldiphenylsulfone, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2, Hindered phenol compounds such as 2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,4-diglycidyloxybenzene, 4,4′-diglycidyloxydiphenylsulfone, 4-benzyloxy-4 ′ -(2-Methylglycyloxy) diphenylsulfone, glycidyl terephthalate, bisphenol A type epoxy resin type, cresolno Epoxy compounds such as borak type epoxy resin and phenol novolak type epoxy resin, N, N′-di-2-naphthyl-p-phenylenediamine, 2,2′-methylenebis (4,6-di-tert-butylphenyl) phosphate Sodium salt or polyvalent metal salt, bis (4-ethyleneiminecarbonylaminophenyl) methane, 4,4′-bis [(4-methyl-3-phenoxycarbonylaminophenyl) ureido] diphenylsulfone, and the following general formula ( 2) and the like, and these storage stabilizers contribute to the storage stability of the printed part 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.)

  Of these storage stabilizers, 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, and at least selected from the diphenylsulfone bridged compound represented by the above general formula (2) It is preferable to contain one or more kinds, and by containing these storage stabilizers, particularly the water resistance of the printed portion in the heat-sensitive recording material is improved.

  The content of the storage stabilizer is preferably 2.5 to 100 parts by mass and more preferably 5 to 50 parts by mass with respect to 100 parts by mass of the developer.

  Examples of the auxiliary agent include, for example, sodium dioctiolsuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, fatty acid metal salt, zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, Waxes such as ester wax, hydrazide compounds such as adipic acid dihydrazide, water resistant agents such as glyoxal, boric acid, dialdehyde starch, methylol urea, glyoxylate, epoxy compounds, antifoaming agents, colored dyes, fluorescent dyes, And pigments.

  The binder used in the heat-sensitive recording layer in the present invention includes fully saponified polyvinyl alcohol having a polymerization degree of 200 to 1900, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, and amide-modified. Polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer and cellulose derivatives such as ethylcellulose and acetylcellulose, polyvinyl acetate , Polyacrylamide, polyacrylate, polyvinyl butyral polystyrene and their Polymers, polyamide resins, silicone resins, petroleum resins, terpene resins, ketone resins, such as chroman resins. These binders can be used singly or in combination of two or more, and can be used by being dissolved in a solvent, or in a state of being emulsified or pasted in water or another medium.

  Examples of pigments blended in the thermosensitive recording layer include silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, zinc oxide, aluminum hydroxide, polystyrene resin, urea-formalin resin, styrene-methacrylic acid copolymer Examples thereof include inorganic or organic pigments such as coalescence, styrene-butadiene copolymer and hollow plastic pigment.

  The types and amounts of basic dyes, color developers, sensitizers, binders, pigments and other additives used in the heat-sensitive recording layer in the present invention are appropriately determined according to the quality performance required for the heat-sensitive recording layer. It is determined.

  In the heat-sensitive recording layer of the present invention, the content of the N-substituted amino acid derivative represented by the general formula (1) as a developer is from 1 part by weight of the basic dye of the heat-sensitive recording layer from the viewpoint of color density. Thus, 0.3 to 5 parts by mass is preferable, and 0.4 to 3 parts by mass is more preferable.

  Further, the sensitizer is suitably 0.2 to 4 parts by mass with respect to 1 part of the leuco dye, and the binder is suitably 5 to 50% by mass in the total solid content. As the support, paper, recycled paper, synthetic paper, plastic film, nonwoven fabric, metal foil or the like can be used. A composite sheet combining these can also be used.

  Moreover, you may provide the overcoat layer which consists of a high molecular substance containing an organic pigment in order to improve storage stability. Further, an undercoat layer containing an organic pigment, an inorganic pigment, hollow fine particles, or the like may be provided for the purpose of preventing wrinkle adhesion to the thermal head, improving the printing image quality, and improving the sensitivity.

In the present invention, the basic dye, developer, sensitizer, and, if necessary, storage stabilizer used for the heat-sensitive recording layer are averaged by a stirring pulverizer such as a ball mill, an attritor, and a sand mill, for example, using water as a dispersion medium. Finely dispersed and used so that the particle size is 2 μm or less.
The heat-sensitive recording layer coating material is prepared by mixing and stirring pigments, binders, auxiliaries, and the like as necessary in the finely dispersed dispersion.
The heat-sensitive recording layer paint thus obtained was applied onto a support so that the coating amount after drying was about 1.5 to 12 g / m ² , more preferably about 3 to 7 g / m ^2. It is formed by drying.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to this. In the examples, “parts” and “%” represent “parts by mass” and “mass%”.

The synthesis example of the N-substituted amino acid derivative used in the examples is illustrated below.
Synthesis Example 1: N- (m-Tolylaminocarbonyl) -phenylalanine Into a four-necked flask equipped with a thermometer, a dropping funnel and a stirrer, 16.5 g of L-phenylalanine and 50 g of water were charged, and the internal temperature was 15 ° C. Then, 50 g of 8% aqueous sodium hydroxide solution was added to dissolve L-phenylalanine. While maintaining the internal temperature at 15 ° C., 13.3 g of m-tolyl isocyanate dissolved in ethyl acetate was added dropwise and stirred for 5 hours. Ethyl acetate was added to the reaction solution, neutralized with dilute hydrochloric acid, and the product was extracted with ethyl acetate. After concentration of ethyl acetate in the extract, toluene was added to the concentrated residue for crystallization. The crystals were filtered off and dried to obtain white crystals of N- (m-tolylaminocarbonyl) -phenylalanine. The melting point was 151 ° C.

Synthesis Example 2: N- (m-tolylaminocarbonyl) -methionine White crystals were obtained in the same manner as in Synthesis Example 1 except that 14.9 g of L-methionine was used instead of 16.5 g of L-phenylalanine in Synthesis Example 1. N- (m-tolylaminocarbonyl) -methionine was obtained. The melting point was 142 ° C.

Synthesis Example 3: N- (m-tolylaminocarbonyl) -valine White crystals were obtained in the same manner as in Synthesis Example 1 except that 11.7 g of L-valine was used instead of 16.5 g of L-phenylalanine of Synthesis Example 1. N- (m-tolylaminocarbonyl) -valine was obtained. The melting point was 169 ° C.

Synthesis Example 4: N- (m-tolylaminocarbonyl) -cysteine-S-benzyl Synthetic Example 1 except that 21.1 g of L-cysteine-S-benzyl was used instead of 16.5 g of L-phenylalanine of Synthesis Example 1. By the same operation, white crystals of N- (m-tolylaminocarbonyl) -cysteine-S-benzyl were obtained. The melting point was 164 ° C.

Synthesis Example 5: N- (m-tolylaminocarbonyl) -tyrosine In the same manner as in Synthesis Example 1 except that 18.1 g of L-tyrosine was used instead of 16.5 g of L-phenylalanine of Synthesis Example 1, white crystals of N- (m-tolylaminosulfonyl) -tyrosine was obtained. The melting point was 161 ° C.

Synthesis Example 6: N-phenylaminothiocarbonyl-glycylglycine In the same apparatus as Synthesis Example 1, 13.2 g of glycylglycine, 50 g of water and 50 g of THF were charged, and 50 g of 8% aqueous sodium hydroxide solution was added to dissolve glycylglycine. . While maintaining the internal temperature at 20 to 25 ° C., 13.5 g of phenyl isothiocyanate was added dropwise and stirred for 5 hours. The same reaction treatment as in Synthesis Example 1 was performed to obtain white crystalline N-phenylaminothiocarbonyl-glycylglycine. The melting point was 157 ° C.

Synthesis Example 7 N- (p-toluenesulfonylaminocarbonyl) -phenylalanine-methyl ester In a four-necked flask equipped with a thermometer, a dropping funnel, and a stirrer, 21.5 g of L-phenylalanine-methyl ester hydrochloride and 120 g of ethyl acetate. Then, 10.1 g of triethylamine was added dropwise while maintaining the internal temperature at 10 ° C. While maintaining the internal temperature at 8 to 10 ° C., 19.7 g of p-toluenesulfonyl isocyanate was added dropwise and stirring was continued for 5 hours. After completion of the reaction, a small amount of acetic acid was added to the reaction solution, water was added, and the organic layer was washed and separated. Toluene was added to the residue obtained by concentrating the organic layer under reduced pressure to precipitate crystals, followed by filtration to obtain white crystalline N- (p-toluenesulfonylaminocarbonyl) -phenylalanine-methyl ester. The melting point was 162 ° C.

Synthesis Example 8: N- (p-toluenesulfonyl) -β-alanine A four-necked flask equipped with a thermometer, a dropping funnel and a stirrer was charged with 8.9 g of β-alanine, 30 g of water, and an 8% aqueous sodium hydroxide solution. The internal temperature was cooled to 10 ° C. 30 g of a THF solution in which 19.1 g of p-toluenesulfonyl chloride was dissolved and 50 g of 8% sodium hydroxide were each divided into four parts, and each fraction was alternately dropped into a flask to carry out a reaction. After stirring for 4 hours, it was acidified with dilute hydrochloric acid. The reaction solution was reacted in the same manner as in Synthesis Example 1 to obtain white crystalline N- (p-toluenesulfonyl) -β-alanine. The melting point was 125 ° C.

  A thermosensitive recording material was prepared by the following operation.

[Create undercoat paint]
100 parts of plastic hollow particles (trade name: Ropaque SN-1055: hollow ratio: 55% solid content 26.5%), 100 parts of 50% dispersion of calcined kaolin, styrene-butadiene latex (trade name: L-1571 solid) (48%), 25 parts, 50 parts of a 10% aqueous solution of oxidized starch and 20 parts of water were mixed to prepare an undercoat paint.

Example 1
[Creation of thermal recording paint]
Liquid A (Preparation of dye dispersion)
3- (N, N-dibutylamino) -6-methyl-7-anilinofluorane 10 parts 10% aqueous polyvinyl alcohol solution 10 parts water 16.7 parts

Liquid B1 (Preparation of developer dispersion)
N- (m-Tolylaminocarbonyl) -methionine (developer 1) 20 parts 10% aqueous polyvinyl alcohol solution 20 parts water 33.3 parts

B2 liquid (preparation of dispersion)
Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea 20 parts 10% aqueous polyvinyl alcohol solution 20 parts water 33.3 parts

Liquid C (Preparation of sensitizer dispersion)
1,2-bis (m-tolyloxy) ethane 15 parts 10% aqueous polyvinyl alcohol solution 15 parts water 25 parts

The dispersion liquids of the liquid A, liquid B and liquid C were pulverized with a sand grinder until the average particle size became 1 μm or less, and the dispersion liquid was mixed at the following ratio to obtain a coating liquid.
Liquid A (dye agent dispersion) 36.7 parts Liquid B1 (developer dispersion) 55.0 parts Liquid B2 (dispersion liquid) 18.3 parts Liquid C (sensitizer dispersion liquid) 55.0 parts

  Aluminum hydroxide (trade name: Heidilite H-42 20 parts, amorphous silica (trade name: Mizukasil P-605) 10 parts, 10% dissolved starch starch 20 parts, zinc stearate dispersion: (trade name: Hydrin Z-8-36) A composition comprising 15 parts of water and 20 parts of water was mixed to prepare a thermal recording paint.

[Creation of thermal recording material]
The undercoat paint was applied to a fine paper (acidic paper) having a basis weight of 53 g as a support and dried so that the mass per area after drying was 6 g / m ^2, and then the area after the heat-sensitive paint was dried The coating was dried so that the weight per hit was 3.5 g / m ² .
This sheet was processed with a super calender so that the smoothness (JISP8155: 2010) was 900 to 1200 s to prepare a heat-sensitive recording material.

[Various tests]
1. Thermal recording test (color development test)
About the created thermosensitive recording material, it applied with the applied energy of 0.38 mJ / dot using the thermosensitive recording paper printing tester (TH-PMD by the Okura Electric Co., Ltd.). The printing density of the recording part was measured with a Macbeth reflection densitometer RD-914.

2. Heat resistance test After the thermal recording material recorded in the thermal recording 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 of the test piece and the density of the unprinted part were measured with a Macbeth reflection densitometer. .

3. Humidity and heat resistance test The thermal recording material recorded in the thermal recording test was left for 24 hours in an environment at a test temperature of 40 ° C and 90% RH, and then the printed image density of the test piece and the density of the unprinted area were measured using the Macbeth reflection densitometer. Measured with

4). Oil resistance test The sample was immersed in the heat sensitive recording material recorded in the heat sensitive recording test for 1 minute in salad oil, and then the oil of the test piece was wiped off, and the image density was measured with a Macbeth reflection densitometer.

5. Water Resistance Test The thermal recording paper recorded in the thermal recording test was immersed in water for 24 hours, then the test piece was air-dried, and the image density and the unprinted part were measured with a Macbeth reflection densitometer.

6). Plasticizer resistance test A wrap film (trade name: High Wrap KMA, manufactured by Mitsui Chemicals) is wrapped around a polycarbonate pipe (48mmφ), and the thermal recording paper recorded in the thermal recording test is placed on it. Wrapped in a triple layer and allowed to stand in an environment of 20 ° C. and 65% RH for 24 hours. Thereafter, the image density and the unprinted portion were measured with a Macbeth reflection densitometer.

  Various test results of the heat-sensitive recording material according to this example are as shown in Table 1.

(Example 2)
Example 1 except that N- (m-tolylaminocarbonyl) -methionine (developer 1) in solution B1 of Example 1 is replaced with N- (m-tolylaminocarbonyl) -phenylalanine (developer 2). The same operation was performed.
Various test results of the heat-sensitive recording material according to this example are as shown in Table 1.

(Example 3)
The same as Example 1 except that N- (m-tolylaminocarbonyl) -methionine (developer 1) in solution B1 of Example 1 was replaced with N- (phenylaminocarbonyl) -methionine (developer 3). The operation was performed.
Various test results of the heat-sensitive recording material according to this example are as shown in Table 1.

(Example 4)
Example 1 except that N- (m-tolylaminocarbonyl) -methionine (developer 1) in solution B of Example 1 was replaced with N- (p-tolylaminocarbonyl) -methionine (developer 4). The same operation was performed.
Various test results of the heat-sensitive recording material according to this example are as shown in Table 1.

(Example 5)
Same as Example 1 except that N- (m-tolylaminocarbonyl) -methionine (developer 1) of B in Example 1 is replaced with N- (m-tolylaminocarbonyl) -valine (developer 5). Was performed.
Various test results of the heat-sensitive recording material according to this example are as shown in Table 1.

(Example 6)
Example 1 except that N- (m-tolylaminocarbonyl) -methionine (developer 1) in solution B of Example 1 was replaced with N- (m-tolylaminocarbonyl) -phenylglycine (developer 6). The same operation was performed. Various test results of the heat-sensitive recording material according to this example are as shown in Table 1.

(Example 7)
Example 1 except that N- (m-tolylaminocarbonyl) -methionine (developer 1) in solution B of Example 1 is replaced with N- (m-tolylaminocarbonyl) -tyrosine (developer 7). The same operation was performed. Various test results of the heat-sensitive recording material according to this example are as shown in Table 1.

[Reference Examples 1 to 7]
In Examples 1 to 7, the same operation as in Examples 1 to 7 was performed except that 77.3 parts of each B1 solution was used and B2 solution was not used. Various test results of the heat-sensitive recording material according to this reference example were as shown in Table 1.

[Comparative Example 1]
The same operations as in Reference Examples 1 to 7 were carried out except that the developer N- (m-tolylaminocarbonyl) -methionine in the B1 liquid of Example 1 was replaced with bisphenol A (developer 8). Various test results of the heat-sensitive recording material according to this comparative example are shown in Table 1.

[Comparative Example 2]
The same operations as in Reference Examples 1 to 7 were carried out except that the developer N- (m-tolylaminocarbonyl) -methionine in the B1 liquid of Example 1 was replaced with 4,4′bisphenol S (developer 9). . Various test results of the heat-sensitive recording material according to this comparative example are shown in Table 1.

As is apparent from the examples and Table 1, the heat-sensitive recording material prepared from the amino acid derivative exhibits a good color density at a high whiteness, in particular, Z is an OH group, X is —NHCO—, N-substituted amino acid derivatives are N- (m-tolylaminocarbonyl) -phenylalanine, N- (m-tolylaminocarbonyl) -methionine, N- (m-tolylaminocarbonyl) -valine, N- (m-tolylaminocarbonyl) ) -Phenylglycine and N- (m-tolylaminocarbonyl) -tyrosine had good heat resistance, moisture resistance, and oil storage stability in the printed and unprinted areas.
Furthermore, the thermosensitive recording material containing Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea contains Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea. Compared with no heat-sensitive recording material, it was excellent in water resistance.

  In the heat-sensitive recording material of the present invention, since the developer used is a natural amino acid as a main raw material, there is no concern about endocrine disruption, excellent color density, high whiteness in non-printed areas, and printing. The storage stability of the part is also good, and the water resistance of the N-substituted amino acid derivative of the developer is further improved by containing Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea. Therefore, industrial applicability as an alternative to conventional heat-sensitive recording materials is very promising.

Claims (3)

A heat-sensitive recording material comprising a heat-sensitive recording layer comprising a colorless or light-colored basic dye at room temperature and a developer capable of developing a color upon contact with the dye on heating, the developer A heat-sensitive recording material containing at least one N-substituted amino acid derivative represented by the following general formula (1) as an agent and containing Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea .
(R-X) _m -Y- (Z) _m (1)
(In Formula (1), R 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 alkoxy group. Represents an aryl group which may have a substituent.
X is a group attached to the N-terminus of _{Y, -OCO -, - SO 2} NHCO -, - NHCO -, - NHCS-, or -SO ₂ - represent.
Y represents an amino acid residue or a peptide residue, and an 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 group or an OR ″ group. The SH group of the cysteine residue may be substituted with the SR group or the SR ″ group, and the NH group of the histidine residue may be substituted with the NR group or the NR ′ group. Well, the NH ₂ group of the lysine residue or ornithine residue may be substituted with an NHR group or an NHR ′ group, R ′ represents an amino protecting group and R ″ represents a carboxy protecting group.
Z is a group bonded to the C terminus of Y and represents an OH group or an OR ″ group.
A plurality of R, R ′, and R ″ may be the same or different, and may be bonded to each other to form a ring.
However, Y is an amino acid residue other than a cystine residue or a peptide residue having no cystine residue, and m = 1. ) The developer is N- (m-tolylaminocarbonyl) -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 are at least one selected from the group consisting of The thermosensitive recording material according to 1. The content of the Np-toluenesulfonyl N′-3- (p-toluenesulfonyloxy) phenylurea is 10 to 400 parts by mass with respect to 100 parts by mass of the developer. The heat-sensitive recording material according to 1 or 2.