JPH04331184A - Thermal recording material - Google Patents

Abstract

PURPOSE:To record at a high speed obtaining high coloring sensitivity by using at least one kind of diphenyl compounds to be expressed by a specific formula as a sensitivity improver, in a material which utilizes the coloring reaction to color developer at a contact of leuco dye. CONSTITUTION:In a thermal recording material which utilizes the coloring reaction between a colorless or monochrome leuco dye and a developer to color the leuco dye at a contact, at least one kind of diphenyl compounds expressed by a formula I written on the right side is to be used as a sensitivity improver. In the formula, X<1>-Z<1>, X<2>-Z<2> represent independently hydrogen atom, alkyl group, halogen atom, alkoxy group, and nitro group, respectively. An n<1> expresses integer of 1-5. Or, benzyl carbamate compound to be expressed by other specific formula or a nitro compound is used as a sensitivity improver. As the developer, any one of various electron accepting compounds is used. Thus, coloring density and sensitivity are raised and high speed recording is possible.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material with excellent color development.

0002

2. Description of the Related Art Various recording materials have been proposed that utilize a color-forming reaction between a colorless or light-colored leuco dye and a color developer due to heat, pressure, or the like. One such heat-sensitive recording material is
There is no need for complicated processes such as developing and fixing, and recording can be done in a short time with relatively simple equipment, there is little noise, and the cost is low. It is useful as a variety of recording materials such as machines, labels, and recorders. Color-forming dyes used in heat-sensitive recording materials include, for example, colorless or light-colored leuco dyes having a lactone, lactam, or spiropyran ring, and organic acids, phenolic substances, and the like have been conventionally used as color developers. Recording materials using this leuco dye and color developer are widely used because of their high image density and high background whiteness.

On the other hand, as the demand for thermal recording methods has increased in recent years, the demand for faster recording has also increased. For this reason, there is a strong desire not only to increase the speed of the recording apparatus itself, but also to develop recording materials that can support this speed.

In order to cope with the increase in recording speed, p-hydroxybenzoic acid ester is used as a high-sensitivity color developer, for example, in Japanese Patent Application Laid-open No. 56-144193.
Although hydroxynaphthoic acid esters have been proposed in Japanese Patent Application No. 2793, etc., recording materials using these compounds have problems in the storage stability of image areas. Furthermore, JP-A-59-16568
No. 0 proposes the use of a thioester compound as a color developer, but recording materials using this compound have high fastness to oils and fats in the image area, but cannot be said to have high sensitivity. In addition, there are various proposals for increasing sensitivity by adding various thermofusible substances; for example, Japanese Patent Laid-Open No. 5
Naphthol derivatives have been proposed in JP-A No. 8-87094, and benzyl biphenyl has been proposed in JP-A-60-82382. However, heat-sensitive recording materials using these color developers or thermofusible substances have problems in terms of color development sensitivity, background whiteness, and storage stability (image fading, white powder generation, etc.).
It is still difficult to say that it is sufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material that has excellent color development sensitivity, is suitable for high-speed recording, and has a high background whiteness.

[0006]

[Means for Solving the Problems] According to the present invention, in a recording material that utilizes a color-forming reaction between a colorless or light-colored leuco dye and a color developer that causes the leuco dye to develop color upon contact, the following formula 1: A heat-sensitive recording material characterized by using a compound represented by chemical formula 2 or chemical formula 3 is provided.

[Formula 1] (wherein, X1, Y1, Z1, X2, Y2, and Z2 each independently represent a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, or a nitro group, and n1 represents an integer of 1 to 5. vinegar)

[Formula 2] (wherein, X3 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, or a lower alkyl group substituted with a halogen atom, and Y3 represents a halogen atom, a lower alkyl group, a lower alkoxy group, or represents a lower alkyl group substituted with a halogen atom, and n2 represents an integer of 0 to 2.)

[Formula 3] (In the formula, R represents an aryl group or an aralkyl group that may have a substituent.)

The heat-sensitive recording material of the present invention contains a diphenyl compound represented by the above formula 1, a diphenyl compound represented by the above formula 2, as a sensitivity improver.
Since the benzylcarbazate compound represented by the above formula or the nitro compound represented by the above formula 3 is used, it has excellent color development sensitivity, is suitable for high-speed recording, and has a high background whiteness.

Specific examples of the diphenyl compound represented by the above formula 1 used in the present invention are listed in Table 1 below, but the present invention is not limited thereto.

[0009]

[Table 1]

Further, specific examples of the benzylcarbazate compound represented by the above formula 2 used in the present invention are listed in Table 2 below, but the present invention is not limited thereto.

[0011]

[Table 2-1]

[Table 2-2]

[0012] Further, specific examples of the nitro compound represented by the above formula 3 used in the present invention are listed in Table 3 below.
The present invention is not limited to these.

[0013]

[Table 3-1]

[Table 3-2]

As the leuco dye used in the present invention, leuco dyes that are generally known for this type of leuco recording material are used, such as triphenylmethane, fluoran, phenothiazine, auramine, and spiropyran. Leuco compounds of such dyes are preferably used. Specific examples of such leuco dyes include:
For example, the following can be mentioned. 3,3-bis(p-dimethylaminophenyl)-phthalide, 3,3-bis(p-dimethylaminophenyl)-6
-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis(p-dimethylaminophenyl)-6-diethylaminophthalide, 3,3-bis(
p-dimethylaminophenyl)-6-chlorophthalide,
3,3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran,
3-dimethylamino-5,7-dimethylfluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-{N-(3'-trifluoromethylphenyl)amino}-6-diethylaminofluorane, 2
-{3,6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam}, 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7- (o
-Chloranilino)fluoran, 3-dibutylamino-
7-(o-chloroanilino)fluorane, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino-
6-Methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N
,N-diethylamino)-5-methyl-7-(N,N-
dibenzylamino)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane, 3-(2'
-hydroxy-4'-dimethylaminophenyl)-3-
(2'-methoxy-5'-chlorophenyl)phthalide,
3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl)
Phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl) phthalide, 3-diethylamino-6-methyl-7-(2',4'- dimethylanilino) fluorane,
3-(2'-Methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl)phthalide, 3-morpholino-7-(N-
propyl-trifluoromethylanilino)fluorane,
3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N-
benzyl-trifluoromethylanilino)fluorane,
3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-
(N-ethyl-p-toluidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-
(o-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7
-piperidinofluorane, 2-chloro-3-(N-
methyltoluidino)-7-(pn-butylanilino)
Fluoran, 3-(N-benzyl-N-cyclohexylamino)-5,6-benzo-7-α-naphthylamino-
4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino-4', 5'-benzofluorane, 3-diethylamino-6-methyl-7-(2',4'
-dimethylanilino)fluoran, etc. 3-(p-dimethylaminophenyl)-3-{1,1-bis(p-dimethylaminophenyl)ethylene-2-yl}phthalide, 3
-(p-dimethylaminophenyl)-3-{1,1-bis(p-dimethylaminophenyl)ethylene-2-yl}-6-dimethylaminophthalide, 3-(p-dimethylaminophenyl)-3- (1-p-dimethylaminophenyl-1-phenylethylene-2-yl)phthalide, 3
-(p-dimethylaminophenyl)-3-(1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl)-6-dimethylaminophthalide, 3-(
4'-dimethylamino-2'-methoxy)-3-(1'
'-p-dimethylaminophenyl-1''-p-chlorophenyl-1'',3''-butadien-4''-yl)benzophthalide, 3-(4'-dimethylamino-2'
-benzyloxy)-3-(1''-p-dimethylaminophenyl-1''-phenyl-1'',3''-butadien-4''-yl)benzophthalide, 3-dimethylamino-6-dimethyl Amino-fluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3,3-
Bis{2-(p-dimethylaminophenyl)-2-(p
-methoxyphenyl)ethenyl}-4,5,6,7-tetrachlorophthalide, 3-bis{1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl}-5,6-dichloro-4 , 7-dibromophthalide, bis(p-dimethylaminostyryl)-1-naphthalenesulfonylmethane, etc.

Further, in the present invention, various electron-accepting compounds such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof, etc. can be used as color developers. Examples include those shown below. 4,4'-isopropylidene bisphenol, 3,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis(o
-methylphenol), 4,4'-secondary butylidene bisphenol 4,4'-isopropylidene bis(
o-tert-butylphenol), 4,4'-cyclohexylidene diphenol, 4,4'-isopropylidene bis(2-chlorophenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-2-methyl)phenol, 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'-thiobis(6-tert-butyl-2-methyl)phenol, 4,4'-
Diphenolsulfone, 4,2'-diphenolsulfone, 4-isopropoxy-4'-hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide,
Isopropyl P-hydroxybenzoate, benzyl P-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate,
1,7-bis(4-hydroxyphenylthio)-3,5
-dioxaheptane, 1,5-bis(4-hydroxyphenylthio)-3-oxapentane, 1,3-bis(4
-hydroxyphenylthio)-propane, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 1,3-bis(4-hydroxyphenylthio)
-2-hydroxypropane, N,N'-diphenylthiourea, N,N'-di(m-chlorophenyl)thiourea,
salicylanilide, 5-chloro-salicylanilide, salicyl-o-chloroanilide, 2-hydroxy-3-naphthoic acid, antipyrine complex of zinc thiocyanate, 2-
Zinc salt of acetyloxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum, calcium, etc. Bis-(4-hydroxyphenyl) Acetic acid methyl ester, bis-(4-hydroxyphenyl)
Benzyl acetate ester, 4-{β-(p-methoxyphenoxy)ethoxy}salicylic acid, 1,3-bis(4-hydroxycumyl)benzene, 1,4-bis(4-hydroxycumyl)benzene, 2,4 '-diphenolsulfone, 3,3'-diallyl-4,4'-diphenolsulfone, α,α-bis(4-hydroxyphenyl)-α-
antipyrine complex of methyltoluene zinc thiocyanate,
Tetrabromobisphenol A, tetrabromobisphenol S, 4,4'-thiobis(2-methylphenol), 4,4'-thiobis(2-chlorophenol)
etc.

In order to obtain the heat-sensitive recording material of the present invention, a leuco dye, a color developer and the above-mentioned auxiliary components may be bonded and supported on a support. As the binder in this case, various conventional binders can be used as appropriate. Specific examples of such binders include the following. Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic acid ester copolymer, acrylamide/acrylic acid ester/
In addition to water-soluble polymers such as methacrylic acid terpolymer, styrene/maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein, polyacetic acid Vinyl, polyurethane, polyacrylic ester,
Emulsions such as polymethacrylic esters, vinyl chloride/vinyl acetate copolymers, ethylene/vinyl acetate copolymers, and latexes such as styrene/butadiene copolymers and styrene/butadiene/acrylic copolymers.

Further, when obtaining a heat-sensitive recording material according to the present invention, the compounds represented by the above formulas 1 to 3 are used as sensitivity improvers, but various thermofusible substances may also be used as necessary. Specific examples include the following compounds. Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, and zinc behenate, p-benzyl Biphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β-naphthoic acid phenyl ester, 1-hydroxy-
2-naphthoic acid phenyl ester, 1-hydroxy-2
-Naphthoic acid methyl ester, diphenyl carbonate, terephthalic acid dibenzyl ester, terephthalic acid dimethyl ester, 1,4-dimethoxynaphthalene, 1,4
-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-bis(phenoxy)ethane, 1,2
-bis(3-methylphenoxy)ethane, 1,2-bis(4-methylphenoxy)ethane, 1,4-bis(phenoxy)butane, 1,4-bis(phenoxy)-2-butene, 1,2- Bis(4-methoxyphenylthio)ethane, dibenzoylmethane, 1,4-bis(phenylthio)butane, 1,4-bis(phenylthio)-2-butene, 1,2-bis(4-methoxyphenylthio)ethane ,
1,3-bis(2-vinyloxyethoxy)benzene,
1,4-bis(2-vinyloxyethoxy)benzene,
p-(2-vinyloxyethoxy)biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, 1,3-dibenzoyloxypropane, dibenzyl disulfide, 1,1-
diphenylethanol, 1,1-diphenylpropanol, p-(benzyloxy)benzyl alcohol, 1,
3-diphenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N
-octadecylcarbamoylbenzene, oxalic acid dibenzyl ester, 1,5-bis(p-methoxyphenyloxy)-3-oxapentane, etc.

In addition, in the present invention, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as
Fillers, surfactants, etc. can be used in combination. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, and surface-treated inorganic fine powders such as calcium and silica. Examples of lubricants include organic fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, and vinylidene chloride resin. Esters, animal products,
Examples include various waxes of vegetable origin, mineral origin, or petroleum origin.

Regarding the layer structure, it may be a single layer or a multilayer, and an over layer, an under layer, and a back layer may be provided as necessary.

In the present invention, the amount of the leuco dye, developer, and sensitizer used is 0 part by weight of the leuco dye, and 0 part by weight of the leuco dye.
．． 5 to 10.0 parts by weight, 0.5 to 10.0 parts by weight of the sensitizer, preferably 1 to 5 parts by weight.

[0021]

EXAMPLES Next, the present invention will be explained in more detail with reference to examples. Note that all parts and percentages shown below are based on weight.

Example 1 The following mixtures were each ground in a magnetic ball mill for two days to prepare [Liquid A], [Liquid B], [Liquid C] and [Liquid D]. [Liquid A] 3-(N-methyl-N-cyclohexyl)amino 20 parts -6-methyl-7-anilinofluorane 10% aqueous solution of polyvinyl alcohol
20 parts water

60 copies [B
Liquid] 4,4'-isopropylidenediphenol
20 parts 10% aqueous solution of polyvinyl alcohol
20 parts water


60 parts [Liquid C] 2-phenylsulfonylacetophenone
20 copies (
Specific example No. of Table 1. (1) Compound) 10% aqueous solution of polyvinyl alcohol
20 parts water

60 parts [Liquid D] Calcium carbonate

20 parts 5% aqueous solution of methylcellulose

20 parts water

60 parts Next [Liquid A] 10
parts, [Liquid B] 30 parts, [Liquid C] 20 parts, and [Liquid D] 40 parts.
Part and Chukyo Yushi Zinc Stearate Dispersion (Product Name: HZ)
730 (concentration 30%) to form a thermosensitive coloring layer forming liquid,
This is coated on high-quality paper weighing 50 g/m2 so that the dye adhesion amount after drying is 0.5 g/m2, and dried to form a heat-sensitive color layer, and the surface smoothness is further increased to 500 to 600 seconds. A heat-sensitive recording material was prepared by calendering the surface of the layer.

Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the following [Liquid E] was used instead of [Liquid C] in Example 1. [Liquid E] 20 parts of 4-hydroxy-4'-isopropoxyphenylsulfone 10% aqueous solution of polyvinyl alcohol
20 parts water

60 copies

0024
Comparative Example 1 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that water was used instead of [liquid C] in the example.

Comparative Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the following [Liquid F] was used instead of [Liquid C] in the Example. [Liquid F] p-benzylbiphenyl
2
0 parts 10% aqueous solution of polyvinyl alcohol
20 copies
water

60 copies

Example 3 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Liquid G] was used instead of [Liquid C] in Example 1. [Liquid G] Specific example No. in Table 2. 1 compound

20 parts 10% aqueous solution of polyvinyl alcohol
20 copies
water

60 copies

Example 4 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Liquid H] was used in place of [Liquid C] in Example 1. [H liquid] Specific example No. in Table 2. 13 compounds

20 parts water

20 parts 10% aqueous solution of polyvinyl alcohol
60 copies

Comparative Example 3 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Liquid I] was used in place of [Liquid C] in Example 1. [Liquid I] p-benzylbiphenyl
2
0 part water

20 parts 10% aqueous solution of polyvinyl alcohol
60 copies

Comparative Example 4 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Liquid J] was used instead of [Liquid C] in Example 1. [Liquid J] Stearic acid amide

20 parts water

20 parts 10% aqueous solution of polyvinyl alcohol
60 copies

Example 5 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the following [Liquid K] was used instead of [Liquid C] in Example 1. [Liquid K] 20 parts of 4-nitrobenzyl-4'-methoxyphenyl ether (Specific example N in Table 3)
o. Compound 4) Polyvinyl alcohol 10
% aqueous solution
20 parts water

60 copies

Example 6 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Liquid L] was used in place of [Liquid C] in Example 1. [Liquid L] 20 parts of 4-nitrobenzyl-4'-chlorocyphenyl ether (Specific example N in Table 3)
o. Compound 8) Water

20 parts 10% aqueous solution of polyvinyl alcohol
60 copies

Comparative Example 5 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Liquid M] was used in place of [Liquid C] in Example 1. [Liquid M] 4-iso-propylbenzyl-4'-
20 copies t
ert-butylphenyl ether water

2
0 parts 10% aqueous solution of polyvinyl alcohol
60 copies

0
[033] The heat-sensitive recording material prepared as described above was printed using a thermal paper color development tester manufactured by Okura Electric Co., Ltd., and the color density was measured using a Macbeth densitometer RD-914. The above results are shown in Table 4.

[0034]

[Table 4] *Applied power: 0.45W/dot Line cycle: 8ms/line

[0035]

Effects of the Invention By using the diphenyl compound represented by the above chemical formula 1, the benzylcarbazate compound represented by the above chemical formula 2, or the nitro compound represented by the above chemical formula 3 as a sensitivity improver, the thermosensitive The recording material has excellent color density and sensitivity, and has high background whiteness.

Claims (3)

[Claims] Claim 1: In a heat-sensitive recording material that utilizes a color-forming reaction between a colorless or light-colored leuco dye and a color developer that causes the leuco dye to develop color upon contact, a sensitivity improver represented by the following formula 1 is used. A heat-sensitive recording material characterized by using at least one kind of diphenyl compound. [Formula 1] (wherein, X1, Y1, Z1, X2, Y2, and Z2 each independently represent a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, or a nitro group, and n1 represents an integer of 1 to 5. vinegar) [Claim 2] In a heat-sensitive recording material that utilizes a color-forming reaction between a colorless or light-colored leuco dye and a color developer that causes the leuco dye to develop color upon contact, a sensitivity improver represented by the following formula 2 is used. A heat-sensitive recording material characterized by using a benzylcarbazate compound. [Formula 2] (wherein, X3 represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, or a lower alkyl group substituted with a halogen atom, and Y3 represents a halogen atom, a lower alkyl group, a lower alkoxy group, or represents a lower alkyl group substituted with a halogen atom, and n2 represents an integer of 0 to 2.) 3. In a heat-sensitive recording material that utilizes a color-forming reaction between a colorless or light-colored leuco dye and a color developer that causes the leuco dye to develop color upon contact, a sensitivity improver represented by the following formula 3 is used. A heat-sensitive recording material characterized by using a nitro compound. [Formula 3] (In the formula, R represents an aryl group or an aralkyl group that may have a substituent.)