JPH06106855A - Thermal recording material - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to obtain a heat-sensitive recording material having high transparency and capable of obtaining a clear copy image at a high exposure speed as a diazo second original. [Structure] A thermosensitive recording material comprising a transparent or semi-transparent support on which a thermosensitive coloring layer utilizing a coloring reaction between a leuco dye and a developer is provided, wherein the dye and the developer in the thermosensitive coloring layer are The thermal recording material is characterized in that the ratio P / R of the amount P other than the included binder and the amount R of the binder is 6.0 or less, and the adhesion amount after drying is 2.0 g.
/ M ² or more is provided, and silica is used for the overcoat layer, the P / R ratio is 0.7 or less, and the surface smoothness is 1000 seconds or more.

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 utilizing a color-forming reaction between a colorless or slightly pale leuco dye at room temperature and a developer attached to the leuco dye. The present invention relates to a heat-sensitive recording material suitable for a field requiring heat resistance.

[0002]

2. Description of the Related Art Recently, various recording materials have been researched and developed and put to practical use in the information recording field in response to social demands such as diversification and increase of information, resource saving and pollution-free. Among them, the heat-sensitive recording material is (1) that a color image is recorded only by heating and a complicated developing step is not required, (2) it can be manufactured using a relatively simple and compact apparatus, and further the obtained recording The material is easy to handle and the maintenance cost is low. (3) In many cases, paper is used as the support. In this case, not only the cost of the support is low, but also the feel of the recorded matter obtained is improved. Because it is similar to plain paper, it is widely used in the fields of computer output, calculators and other printers, medical measurement recorders, high-speed facsimiles, automatic ticket vending machines, and thermal copying. To have.

Further, in recent years, it has been widely used in the CAD field, the second original drawing of diazo, etc., and the demand for a heat-sensitive recording material using a transparent or translucent synthetic paper or a resin film has increased, and the transparency of the support is increased. There is a need for a highly transparent heat-sensitive recording material that makes the most of this.

The above-mentioned heat-sensitive recording material is produced by applying a heat-sensitive color-forming layer liquid containing a color-forming component capable of causing a color-developing reaction to a support on a support such as a synthetic paper or a resin film, and drying it. The color image is recorded on the heat-sensitive recording material obtained by heating with a hot pen or a heat head, but a heat-sensitive color-forming layer or an overcoat layer is coated on transparent or translucent synthetic paper, a resin film or the like. However, sufficient transparency is not obtained.

Further, when copying such a heat-sensitive recording material as a diazo second original image onto diazo paper, the background portion of the copied image is completely exposed unless the copying speed is slowed down as compared with the second original image of the electrostatic recording system. However, there is a drawback that the color develops blue after development and the contrast with the image area deteriorates, which is not yet satisfactory.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a heat-sensitive recording material which has improved the above-mentioned conventional drawbacks, has high transparency, and can be clearly copied as a diazo second original image at a high exposure speed.

[0007]

The present invention provides a thermosensitive recording material comprising a transparent or translucent support and a thermosensitive coloring layer utilizing a coloring reaction between a leuco dye and a color developer on a transparent or translucent support.
The ratio P / R of the amount P of the binder and the amount P other than the binder including the dye and the color developer in the thermosensitive coloring layer is 4.0.
The heat-sensitive recording material is characterized in that it is 6.0 or more. Further, it is preferable to provide an overcoat layer having an adhesion amount after drying of 2.0 g / m ² or more and 4.0 g / m ² or less. Then, silica is used for the overcoat layer, and the P / R ratio is preferably 0.5 or more and 0.7 or less. Further, it is preferable that the surface smoothness is 1000 seconds or more and 4000 seconds or less.

In the above, P is the amount of dye, developer, filler, lubricant and the like, and R is the amount of binder such as resin. In the present invention, it was found that the transparency can be improved by setting P / R to 6.0 or less. If this ratio exceeds 6.0, the transparency will decrease. Conversely, if too much binder is added, the transparency will improve, but the color development function will be impeded by the binder, and the color development sensitivity will decrease. The P / R ratio is preferably in the range of 5.0 to 6.0.

Further, silica is used for the overcoat layer,
The P / R ratio is set to 0.5 or more and 0.7 or less, and the amount of the overcoat adhered after the dry weight is 2.0 g / m ² or more and 4.0 g /
A recording material having a high degree of transparency can be obtained by setting it to m ² or less. The use of silica results in higher transparency than other matching aids.

With respect to the P / R ratio of the overcoat layer (P in this case is silica or the like), if P is reduced, head matching deteriorates and sticking debris occurs, and if R is reduced, transparency decreases. The optimum P / R ratio is preferably about 0.6. Further, if the amount of adhesion after drying is less than 2.0 g / m ² , the transparency is also lowered, and conversely, if it is increased, the coloring sensitivity is lowered, which is not preferable. Especially 2.5g
/ M ^{2 to} 3.5 g / m ² is preferable.

The surface smoothness is reduced to 10 by the calendar processing.
It is preferable to set the time to 00 seconds or more, but if it is less than 1000 seconds, there are many irregular reflections on the surface and the transparency becomes low. Conversely, if the smoothness is too high, there is a concern that the background color will be developed in the calendar processing step. The smoothness that satisfies both crystal qualities is 200
0 to 3000 seconds is preferable.

As the binder added to the heat-sensitive color forming layer for improving transparency, the materials mentioned later as the binder can be used, but polyvinyl alcohol is more preferable, and itaconic acid-modified polyvinyl alcohol is preferable.

The leuco dyes used in the present invention may be applied alone or in admixture of two or more, and as such leuco dyes, those applied to the recording material of this kind may be arbitrarily applied, for example, trile dyes. Phenylmethanephthalide type, triallylmethane type, fluorane type, phenothiazine type, thiofluorane type, xanthene type, indophthalyl type, spiropyran type, azaphthalide type, chromenopyrazole type, methine type, rhodamine anilinolactam type,
Leuco compounds such as rhodamine lactam type, quinazoline type, diazaxanthene type and bislactone type are preferably used. Examples of such compounds include those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide 3,3-bis (p-dimethylaminophenyl) -6 -Diethylaminophthalide 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide 3,3-bis (p-dibutylaminophenyl) phthalide 3-cyclohexylamino-6-chlorofluorane 3-dimethylamino-5 7-Dimethylfluorane 3- (N-methyl-N-isoamylamino) -6-methyl-7-anilinofluorane 3- (N-methyl-N-isobutylamino) -6-methyl-7-anilinoflu Oran 3- (Np-tolyl-N-ethylamino) -6-methyl-7-anilinofluorane 3- (N-methyl-N-a Milamino) -6-methyl-
7-anilinofluorane 3- (N, N-di-n-amylamino) -6-methyl-
7-anilinofluorane 3- (N-methyl-N-cyclohexylamino) -6-
Methyl-7-anilinofluorane 3- (N-methyl-N-iso-propylamino) -6
-Methyl-7-anilinofluorane 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane 3-diethylamino-7,8-benzfluorane 3-diethylamino-7 -Chlorofluorane 3-diethylamino-7-methylfluorane 3-diethylamino-6-methyl-7-chlorofluorane 3-virolidino-6-methyl-7-anilinofluorane 3-diethylamino-6-methyl-7- (M-Trichloroanilino) fluorane 3-diethylamino-7- (o-chloroanilino) fluorane 3-dibutylamino-7- (o-chloroanilino) fluorane 3-diethylamino-6-methyl-7-anilinofluorane 3-dibutyl Amino-6-methyl-7-anilinofluorane 3-diethylamino- - methyl-7- (2 ', 4'-
Dimethylanilino) fluorane 3- (N, N-diethylamino) -5-methyl-7-
(N, N-Dibenzylamino) fluorane benzoyl leuco methylene blue 6'-chloro-8'-methoxybenzoindolinospiropyran 6'-bromo-8'-methoxybenzoindolinospiropyran 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- (2′-methoxy-4′-dimethylaminophenyl) -3- (2′-hydroxy-4′-chloro-5′-
Methylphenyl) phthalide 3-morpholino-7- (N-propyltrifluoromethylanilino) fluorane 3-pyrrolidino-7-trifluoromethylanilinofluorane 3-diethylamino-5-chloro-7- (N-benzyl-tri Fluoromethylanilino) fluorane 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluorane 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluorane 3- (N-ethyl-N- p-toluidino) -7- (α-
Phenylethylamino) fluorane 3-diethylamino-7- (o-methoxycarbonylphenylethylfluorane 3-diethylamino-5-methyl-7- (α-phenylethylamino) fluorane 3-diethylamino-7-piperidinoaminofluorane 2-chloro-3- (N-methyltoluidino) -7- (p
-N-butylanilino) fluorane 3,6-bis (dimethylamino) fluorene spiro (9,3 ')-6'-dimethylaminophthalide 3- (N-ethyl-N-cyclohexylamino) -5
6-benzo-7-α-naphthylamino-4′-bromofluorane 3-diethylamino-6-chloro-7-anilinofluorane 3- (N-ethyl-N-2-ethoxypropylamino)
-6-Methyl-7-anilinofluorane 3- (N-ethyl-N-tetrafurfurylamino) -6
-Methyl-7-anilinofluorane 3-diethylamino-6-methyl-7-mesitidino-
4 ', 5'-benzofluorane 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" -butadiene-4 "-yl) benzophthalide 3- (4'-dimethylamino-2'-benzyloxy)
-3- (1 "-p-dimethylaminophenyl-1" -phenyl-1 ", 3" -butadiene-4 "-yl) benzophthalide 3-dimethylamino-6-dimethylamino-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-dimethylamino Styryl) -1-naphthalenesulfonylmethane bis (p-dimethylaminostyryl) -1-p-tolylsulfonylmethane and the like.

In the present invention, various electron-accepting compounds such as a phenolic compound, a thiophenolic compound, a thiourea derivative, an organic acid and a metal salt thereof can be used as a color developer. Specific examples thereof include the following, but are not limited to these.

4,4'-isopropylidene diphenol, 4,4'-isopropylidene bis-o-methylphenol, 4,4'-sec-butylidene bisphenol, 4,4'-isopropylidene bis (2-tert) −
Butylphenol), zinc p-nitrobenzoate, 1,
3,5-Tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzylisocyanuric acid, 2,2
-(3,4'-dihydroxyphenyl) propane, bis (4-hydroxy-3-methylphenyl) sulfide,
4- {β- (p-methoxyphenoxy) ethoxy} salicylic acid, 1,7-bis (4-hydroxyphenylthio)
3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane, phthalic acid monobenzyl ester monocalcium salt, 4,4′-cyclohexylidene diphenol, 4,4′- Isopropylidene bis (2-chlorophenol), 2,2'-methylene bis (4-methyl-6-tert-butylphenol), 4,4'-butylidene bis (6-tert-butyl-2-methylphenol), 1,1 , 3-Tris (2
-Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis (6-tert-butyl-2-methylphenol), 4,4'-diphenolsulfone, 4-isopropoxy-4'- Hydroxydiphenyl sulfone, 4-benzyloxy-4′-hydroxydiphenyl sulfone, 4,4′-diphenol sulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl brotocatechuate,
Stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis (4-hydroxyphenylthio) propane, N, N'-diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicyl Anilid,
Methyl bis- (4-hydroxyphenyl) acetate, bis-
Benzyl (4-hydroxyphenyl) acetate, 1,3-bis (4-hydroxyphenyl) benzene, 4,4-bis (4-hydroxyphenyl) benzene, 2,4-diphenolsulfone, 2,2′-diallyl- 4,4'-hydroxyphenyl sulfone, 3,4-dihydroxy-4 '
-Methyldiphenyl sulfone, 1-acetyloxy-2
-Zinc naphthoate, zinc 2-acetyloxy-3-naphthoate, zinc 2-acetyloxy-1-naphthoate,
α, α-bis (4-hydroxyphenyl) α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4′-thiobis (2-methylphenol),
4,4'-thiobis (2-chlorophenol) and the like.

In order to produce the heat-sensitive recording material of the present invention, a leuco dye, a developer, 1,4-diethoxynaphthane and other auxiliary agents may be supported and bound on a support. As the binder in this case, various conventional binders can be used in appropriate amounts, and specific examples thereof include the following.

Polyvinyl alcohol, starch and its derivatives, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose,
Cellulose derivatives such as ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene /
Maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein and other water-soluble polymers, as well as polyvinyl acetate, polyurethane, polyacrylic ester, poly Methacrylic acid ester, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer emulsion, styrene / butadiene / acrylic copolymer latex and the like.

Further, in the present invention, various heat-fusible substances may be used in combination as the sensitivity improver, and specific examples thereof include the followings, but the present invention is not limited thereto. . Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and baltimic 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, phenyl β-naphthoate, 1-hydroxy-
Phenyl 2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, glare coal carbonate, dibenzyl terephthalate, dimethyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4 -Dibenzyloxynaphthalene, 1,2-diphenoxyethane, 1,2-bis (3-
Methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-diphenoxybutane,
1,4-diphenoxy-2-butene, 1,2-bis (4
-Methoxyphenylthio) ethane, dibenzoylmethane, 1,4-diphenylthiobutane, 1,4-diphenylthio-2-butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis ( 2-vinyloxyethoxy) benzene, p- (2-vinyloxyethoxy) biphenyl, p-aryloxybiphenyl, p-
Propagyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyl disulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p-benzyloxybenzyl alcohol, 1,3-phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, 1,2
-Bis (4-methoxyphenoxy) propane, 1,5-
Bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, bis (4-methylbenzyl) oxalate, bis (4-chlorobenzyl oxalate) and the like.

Further, as a filler added to the thermosensitive coloring layer,
For example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate,
Clay, talc, inorganic fine powder such as surface-treated calcium and silica, urea formalin resin, styrene /
Organic fine powders such as methacrylic acid copolymers and polystyrene resins can be mentioned. However, the addition of a large amount of them all reduces the transparency, so the addition amount is kept to the minimum.

[0021]

EXAMPLES The present invention will be described in more detail by way of examples. All parts and percentages are by weight.

According to the following composition, {solution A}, solution {B},
{C liquid} and {D liquid} were prepared.

{A liquid} Zinc thiocyanate antipyrine complex 100 parts Dibenzoyloxymethane 70 parts Calcium carbonate 20 parts Itaconic acid modified polyvinyl alcohol 10% aqueous solution 180 parts Water 240 parts {B liquid} 3- (N-methyl-N- Cyclohexyl) amino-6-methyl-7-anilinofluorane 300 parts Itaconic acid-modified polyvinyl alcohol 10% aqueous solution 300 parts Water 400 parts The above {A solution} and {B solution} are dispersed by a ball mill for 72 hours respectively, and The thermosensitive color forming layer forming solutions I and II were prepared.

Solution I {solution A} 500 parts Itaconic acid-modified polyvinyl alcohol 10% aqueous solution 300 parts {solution B} 200 parts water 100 parts solution II {solution A} 500 parts {solution B} 200 parts water 400 parts {solution C } Silica 20 parts Itaconic acid modified polyvinyl alcohol 10% aqueous solution 600 parts Zinc stearate 20 parts Water 400 parts {D liquid} Urea formalin resin 20 parts Itaconic acid modified polyvinyl alcohol 10% aqueous solution 600 parts Zinc stearate 20 parts Water 400 parts Above The {C liquid} and {D liquid} compositions were dispersed by a ball mill to prepare a protective layer forming liquid.

Example 1 ^On a semitransparent synthetic paper having a basis weight of 60 g / m ² , the thermosensitive coloring layer forming liquid I liquid was applied and dried with a wire bar so that the weight after drying was 4 g / m ² . Protective layer forming liquid {C liquid} on it
Was coated and dried with a wire bar so that the weight after drying was 3 g / m ^2, and the surface was subjected to calendering so as to have a smoothness of 2000 to 4000 sec to prepare a heat-sensitive recording material of the present invention.

Example 2 A thermosensitive recording material of the present invention was prepared in the same manner as in Example 1 except that calendering was performed so that the surface smoothness was 1000 sec.

Example 3 A thermal recording material was prepared in the same manner as in Example 1 except that the amount of the protective layer deposited after drying was 2 g / m ² and the calendering was carried out in the same manner as in Example 2.

Comparative Example 1 A thermosensitive color forming layer forming liquid II was used, and a protective layer forming liquid was used as {D liquid}.
m ² and a surface smoothness on a calender of 500 sec were obtained to obtain a heat-sensitive recording material.

Comparative Example 2 A thermosensitive recording material was obtained in the same manner as in Example 1 except that the thermosensitive color forming layer forming liquid II was used.

The heat-sensitive recording materials obtained in the above Examples and Comparative Examples were tested for transparency, and the results are shown in Table 1. In addition, the transparency test method is measured by pressing the coated surface upward with a photobolt green filter and pressing it with a black cylinder. 100-Measured value with photovolt = transparency (%).

[0031]

[Table 1]

As is clear from the results shown in the table, the heat-sensitive recording material of the present invention showed excellent transparency.

[0033]

The heat-sensitive recording material of the present invention has high transparency,
A clear copy image can be obtained at a high exposure speed as the diazo second original image.

Claims (4)

[Claims] 1. A thermosensitive recording material comprising a transparent or translucent support on which a thermosensitive coloring layer utilizing a coloring reaction between a leuco dye and a developer is provided. A heat-sensitive recording material, wherein the ratio P / R of the amount P of the binder other than the binder and the amount R of the binder is 4.0 or more and 6.0 or less. 2. The heat-sensitive recording material according to claim 1, further comprising an overcoat layer having an adhesion amount after drying of 2.0 g / m ² or more and 4.0 g / m ² or less. 3. The silica is used for the overcoat layer, and P
The thermal recording material according to claim 2, wherein the / R ratio is 0.5 or more and 0.7 or less. 4. The heat-sensitive recording material according to claim 1, which has a surface smoothness of 1000 seconds or more and 4000 seconds or less.