JP3214905B2 - Thermal recording material - Google Patents

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 having good image stability.

[0002]

2. Description of the Related Art In general, a thermosensitive recording material mainly comprises a color developing system comprising a colorless or pale-color coloring dye as a coloring agent on a support such as paper, synthetic paper, plastic film and the like, and a developing agent which causes the coloring to occur when heated. A thermosensitive coloring layer as a component is provided, and a colored image can be obtained by heating with a hot pen, a thermal head, a laser beam, a strobe lamp or the like. Compared to other recording materials, this recording material can be recorded in a short time with a relatively simple device without performing complicated processing such as development and fixing, has low noise generation and environmental pollution, and has a low cost. It is used for copying books, documents, etc. due to its low cost and other advantages, as well as electronic calculators, facsimile machines, ticket vending machines,
It is useful as various recording materials such as label printers and recorders.

As a color-forming dye used in a heat-sensitive recording material, for example, a colorless or light-colored leuco dye having a lactone, lactam or spiropyran ring is used. ing. Recording materials using this color former and developer are widely used because of their high image density and high whiteness of the background.

However, such a leuco dye-based color image has poor storage stability, and it is difficult to store a printed image as it is for a long period of time. Further, there is a disadvantage that the image is easily erased by touching oils and fats such as fingerprints and mechanical fats.

In order to enhance the long-term preservation of such leuco dye-based color images, for example, JP-A-60-187584.
Has proposed a method in which hindered amines and hindered phenols are contained in a heat-sensitive recording layer as image stabilizers. JP-A-59-194890 proposes to use a mixture of a salicylic acid derivative or a metal salt thereof and a hydroxybenzoic acid derivative as a developer.

Further, in order to improve image stability against oils and fats, JP-A-57-6795 discloses that a metal salt of an aliphatic carboxylic acid or a metal salt of an aromatic carboxylic acid is used alone or together with a phenolic compound as a color developer. It has been proposed to use. JP-A-59-185693 proposes to use a polyvalent metal salt of an aliphatic organic acid and an aromatic carboxylic acid as a color developer. However, it is difficult to say that any of these methods has sufficient image storability and stability, and is not practical at present.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which is excellent in long-term storage of a color image and stability against fats and oils.

[0008]

According to the present invention, there is provided a heat-sensitive recording material having a heat-sensitive recording layer containing, as a main component, a leuco dye on a support and a color developing agent which makes the leuco dye develop a color when contacted. A heat-sensitive recording material is provided, wherein the heat-sensitive recording layer further contains any of the following dicarboxylic acid derivatives having two aliphatic carboxyl groups.

[0009]

The above aliphatic carboxy used in the present invention
The dicarboxylic acid derivatives having two xyl groups are listed in Table 1 below.
Shown in

[0011]

[Table 1]

The leuco dye used in the present invention is:
The leuco dye may be used alone or as a mixture of two or more types. As such a leuco dye, those applied to this type of recording material are arbitrarily applied. For example, triphenylmethanephthalide type, triallylmethane type , Fluoran, phenothiazine, thioferoran, xanthene, indophthalyl, spiropyran, azaphthalide, chromenopyrazole, methine, rhodamine anilinolactam, rhodamine lactam, quinazoline, diazaxanthen, Leuco compounds such as bislactones are preferably used. Examples of such compounds include, for example, 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-chlorofluoran 3-dimethylamino-5 7-dimethylfluoran 3- (N-methyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3- (N-methyl-N-isobutylamino) -6-methyl-7-anilinofur Oran 3- (Np-tolyl-N-ethylamino) -6-methyl-7-anilinofluoran 3- (N-methyl-NA) Milamino) -6-methyl-
7-anilinofluoran 3- (N-methyl-N-cyclohexylamino) -6
Methyl-7-anilinofluoran 3- (N-methyl-N-iso-propylamino) -6
-Methyl-7-anilinofluoran 3- (N-methyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3-diethylamino-7,8-benzfluoran 3-diethylamino-7 -Chlorofluorane 3-diethylamino-7-methylfluorane 3-diethylamino-6-methyl-7-chlorofluorane 3-pyrrolidino-6-methyl-7-anilinofluoran 3-diethylamino-6-methyl-7- (M-trichloroanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-dibutylamino-7- (o-chloroanilino) fluoran 3-diethylamino-6-methyl-7-anilinofluoran 3-dibutyl Amino-6-methyl-7-anilinofluoran 3-diethylamino- - methyl-7- (2 ', 4'-
Dimethylanilino) fluoran 3- (N, N-diethylamino) -5-methyl-7-
(N, N-dibenzylamino) fluoran benzoyl leucomethylene 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) fluoran 3-pyrrolidino-7-trifluoromethylanilinofluoran 3-diethylamino-5-chloro-7- (N-benzyl-tri Fluoromethylanilino) fluoran 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluoran 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluoran 3- (N-ethyl-N- p-Toluidino) -7- (α-
Phenylethylamino) fluoran 3-diethylamino-7- (o-methoxycarbonylphenylethyl) fluoran 3-diethylamino-5-methyl-7- (α-phenylethylamino) fluoran 3-diethylamino-7-piperidinoaminofluoran 2-chloro-3- (N-methyltoluidino) -7- (p
-N-butylanilino) fluorane 3,6-bis (dimethylamino) fluorenespiro (9,3 ')-6'-dimethylaminophthalide 3- (N-ethyl-N-cyclohexylamino) -5
6-benzo-7-α-naphthylamino-4′-bromofluorane 3-diethylamino-6-chloro-7-anilinofluoran 3- (N-ethyl-N-2-ethoxypropylamino)
-6-methyl-7-anilinofluoran 3- (N-ethyl-N-tetrafurfurylamino) -6
-Methyl-7-anilinofluoran 3-diethylamino-6-methyl-7-mesitidino-
4 ', 5'-benzofluoran 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-dichloro4,7-dibromophthalide bis (p-dimethylaminostyryl ) -1-Naphthalenesulfonylmethane bis (p-dimethylaminostyryl) -1-p-tolylsulfonylmethane and the like.

In the present invention, various compounds having an electron accepting property, for example, phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof can be used as a color developer. Specific examples thereof include the following, but are not limited thereto.

4,4′-isopropylidene diphenol 4,4′-isopropylidenebis-o-methylphenol 4,4′-sec-butylidenebisphenol 4,4′-isopropylidenebis (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′-cyclohexylidenediphenol 4,4′-isopropylidenebis (2-chlorophenol ) 2,2'-methylenebis (4-methyl-6-tert-
Butylphenol) 4,4'-butylidenebis (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'-hydroxydiphenylsulfone 4-benzyloxy-4'- Hydroxydiphenyl sulfone 4,4′-diphenol sulfoxide p-hydroxypropyl benzoate benzyl p-hydroxybenzoate benzyl protocatechuate stearyl gallate lauryl gallate octyl 1,3-bis (4-hydroxyphenylthio) -propane N N, N'-di (m-chlorophenyl) thiourea salicylanilide bis- (4-hydroxyphenyl) acetate methyl bis (4-hydroxyphenyl) acetate 1,3-bis (4-hydroxy Phenyl ) Benzene 1,4-bis (4-hydroxyphenyl) benzene 2,4′-diphenolsulfone 2,2′-diallyl-4,4′-hydroxyphenylsulfone 3,4-dihydroxy-4′-methyldiphenylsulfone 1 -Acetyloxy-2-naphthoic acid zinc 2-acetyloxy-3-naphthoic acid zinc 2-acetyloxy-1-naphthoic acid 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, a compound of the present invention and other auxiliaries may be supported on a support. As the binder in this case, various conventional binders can be used in an appropriate amount, and specific examples thereof include the following.

Polyvinyl alcohol, starch and derivatives thereof, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose,
Cellulose derivatives such as ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene /
Maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, water-soluble polymers such as polyacrylamide, sodium alginate, gelatin and casein, as well as polyvinyl acetate, polyurethane, polyacrylate and polyacrylate Emulsions such as methacrylates, vinyl chloride / vinyl acetate copolymers, ethylene / vinyl acetate copolymers, and latexes such as styrene / butadiene / acrylic copolymers.

Further, in the present invention, various heat-fusible substances can be used as the sensitivity improver, and specific examples thereof include, but are not limited to, the following. Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearamide and palmitamide, 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, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl Carbonate, gliacol carbonate, dibensil 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 -Propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyldisulfide,
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.

When a heat-sensitive recording material is obtained according to the present invention, a leuco dye, a color developer, and the compound of the present invention may be used together with, if necessary, additional components commonly used in this type of heat-sensitive recording material.
For example, a filler, a surfactant, a lubricant, a pressure coloring inhibitor, and the like can be used in combination. In this case, as a filler, for example, inorganic fine powders such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium and silica, and urea -Organic fine powders such as formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, and vinylidene chloride-based resin.

The layer structure may be a single layer or a multi-layer, and if necessary, an over layer, an under layer and a back layer can be provided.

[0021]

Next, the present invention will be described in more detail by way of examples. All parts and percentages shown below are based on weight.

Examples 1 and 2 and Comparative Examples 1 to 3 The following mixtures were pulverized in a magnetic ball mill for 2 days to prepare [Solution A], [Solution B], [Solution C] and [Solution D]. .

[Solution A] 3- (N, N-dinorbutylamino) -6-methyl-7-anilinofluoran 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water 60 parts [Solution B] 4,4'- Isopropylidene diphenol 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts [liquid C] Compound having an image stabilizing action shown in Table 2 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts [liquid D] carbonic acid Calcium 20 parts 5% aqueous solution of methylcellulose 20 parts Water 60 parts

Next, [Part A] 10 parts, [Part B] 30 parts,
30 parts of [Liquid C], 30 parts of [D liquid] and 10 parts of a 20% aqueous alkali solution of isobutylene / maleic anhydride copolymer were mixed to form a thermosensitive color-forming layer forming solution, which was then weighed to 50 g / m2.
⁽² ) Applying and drying a heat-sensitive coloring layer so that the amount of dye after drying becomes 0.5 g / m ² on a high-quality paper, and then providing a layer surface so that the surface smoothness becomes 500 to 600 seconds. Was calendered to produce a heat-sensitive recording material.

The heat-sensitive recording material obtained as described above was heated to a temperature of 150 using a thermal gradient tester manufactured by Toyo Seiki Seisaku-sho, Ltd.
The image density and the background density were measured with a Macbeth densitometer RD-914 (filter: W-106) at a temperature of 2 ° C. and a pressure of 2 kg / cm ^{2 for} 1 second, and the values were taken as the densities before the test.

Next, the samples after printing were tested for storage stability and oil resistance in the following manner. Table 2 shows the results.

Storage Property: The density of the image area after the print sample was stored for 48 hours at a temperature of 40 ° C., a humidity of 90% and a temperature of 60 ° C. for 48 hours was measured. Oil resistance: The density of the image area was measured after applying cottonseed oil to the printed area and storing it at a temperature of 40 ° C. under dry conditions for 16 hours.

The density measurement after each of the above storage tests was also carried out using a Macbeth densitometer RD-914 (filter: W-106).

[0029]

[Table 2]

From Table 2 , it can be seen that the heat-sensitive recording material of the present invention has improved storage stability and oil resistance in the image area, and is extremely excellent in that image fading hardly occurs.

[0031]

As described above, the heat-sensitive recording material of the present invention in which the dicarboxylic acid derivative represented by the above general formula is contained in the heat-sensitive coloring layer of the present invention has extremely high image area stability and practical use. Is high.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-207283 (JP, A) JP-A-3-219993 (JP, A) JP-A-5-301452 (JP, A) JP-A-5-205 116461 (JP, A) JP-A-5-294063 (JP, A) JP-A-3-17181 (JP, A) JP-A-3-23289 (JP, A) JP-A-2-67185 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B41M 5/28-5/34

Claims (1)

(57) [Claims] 1. A heat-sensitive recording material having a heat-sensitive recording layer mainly composed of a leuco dye on a support and a color developer for developing a color when the leuco dye is contacted, wherein the heat-sensitive recording layer further has the following aliphatic property: A heat-sensitive recording material comprising any one of dicarboxylic acid derivatives having two carboxyl groups. Embedded image