JP3504515B2 - Thermal recording material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a good whiteness in the background portion and a high stability in the color-developed portion. In particular, it is difficult for the image to be erased due to the adhesion of oil etc. The present invention relates to a heat-sensitive recording material that is hard to dissolve in an image and is difficult to blur an image.

[0002]

BACKGROUND OF THE INVENTION A heat-sensitive recording material is generally a heat-sensitive recording layer containing an electron-donating, usually colorless or light-colored dye precursor on a support and an electron-accepting developer for coloring the dye precursor. With a thermal head (thermal head),
By heating with a hot pen, laser light, or the like, a dye precursor and a developer react instantaneously to obtain a colored image. JP-B-43-4160 and JP-B-45-14.
It is disclosed in Japanese Patent Publication No. 039.

Such a heat-sensitive recording material has the advantages that recording can be obtained with a relatively simple device, that maintenance is easy, and that noise is not generated, and it is used in measurement recorders, facsimiles, printers, computers. It is used in a wide range of fields such as terminals, labels and ticket vending machines.

Conventionally, a heat-sensitive recording material containing a dye precursor and a color developer as main components has a problem that the color-developed portion is not sufficiently stable and is easily discolored by external stimuli such as heat, humidity and chemicals. In order to improve the stability of the colored portion, various dye precursors, developers, additives, etc. have been proposed,
The stability of the color development part is not yet sufficient.

The stability of the color-developing portion is greatly influenced by the type of the color developing agent. Examples of the color developer that develops the color of the dye precursor include phenol derivatives, salicylic acid derivatives, aromatic carboxylic acid derivatives and their polyvalent metal salts, organic color developers such as novolac phenol resin, silica, acid clay, activated clay, and attapulgite. , Active inorganic pigments such as zeolite, bentonite, and kaolin. Of these, the active inorganic pigments have good stability in the color-developed area, and in particular, the image may be erased due to the adhesion of oil or the like, or the color-developed material in the image area may be dissolved in oil or the like to prevent the image from bleeding. It is widely used for pressure recording materials, but when it is used as a color developer for heat-sensitive recording materials, the unprinted area also develops color, the whiteness of the background is high, and the color development area is stable. A heat-sensitive recording material having good properties cannot be obtained.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, the whiteness of the background part is good, and the stability of the color development part is high. In particular, the image is erased or oil is adhered to the adhering oil. The present invention relates to a heat-sensitive recording material that dissolves in oil or the like and is less likely to blur an image.

[0007]

SUMMARY OF THE INVENTION The above-mentioned problems are, in a heat-sensitive recording material comprising a support and a heat-sensitive recording layer mainly containing a heat-sensitive recording component which reacts with heat to develop a color, the heat-sensitive recording component is usually colorless or colorless. An electron-donating dye precursor of a light color, and an active inorganic pigment that develops the dye precursor, and the usually colorless or light-colored electron-donating dye precursor, or an active inorganic pigment that forms a color of the dye precursor. At least one of which is contained in the heat-sensitive recording layer in the form of particles provided with a color-regulating layer obtained by polymerizing a compound having an unsaturated carbon bond on the surface. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive recording component used in the heat-sensitive recording material of the present invention is usually composed of a colorless or light-colored electron-donating dye precursor, and an active inorganic pigment capable of coloring the dye precursor. At least one of the dye precursor and the active inorganic pigment is contained in the heat-sensitive recording layer in the form of particles having a color-developing layer provided on the surface thereof. Further, both the dye precursor and the active inorganic pigment may be contained in the heat-sensitive recording layer in the form of particles having a color-developing control layer provided on the surface thereof. By providing the color forming control layer on the surface of the dye precursor and / or the active inorganic pigment, it is possible to prevent the dye precursor and the active inorganic pigment from reacting to form a color in the unprinted portion.

In the present invention, the color forming layer provided on the surface of the dye precursor and / or the active inorganic pigment is obtained by polymerizing a compound having an unsaturated carbon bond. By forming the color-adjusting layer by polymerizing a compound having an unsaturated carbon bond, the characteristics of the color-adjusting layer can be freely controlled, and the thickness of the color-adjusting layer is uniform and the thickness of the layer is wide. Can be changed. Further, since a thinner and uniform color adjusting layer can be formed, there is an advantage that the color developing sensitivity of the heat-sensitive recording material can be further increased. On the other hand, in the case of forming the color-regulating layer using a conventionally performed interfacial polymerization method, it is necessary to liquefy the surface coating compound by a method such as dissolving it in an organic solvent. It is extremely difficult to provide a color control layer on the surface of the active inorganic pigment.

Further, at the time of printing, the color development control layer is destroyed, and the dye precursor and the active inorganic pigment react to develop color.
The temperature at which the color control layer is destroyed can be adjusted by changing the material, thickness, etc. of the color control layer, which affects the ease of color development and color sensitivity of the unprinted portion. Since the color development sensitivity decreases as the unprinted area becomes less likely to develop color, it is necessary to adjust the characteristics of the color development control layer in consideration of the balance between the two.

The color-regulating layer contains a dye precursor or an active inorganic pigment dispersion containing a compound having an unsaturated carbon bond,
After adding a polymerization initiator, by heating if necessary, a compound having an unsaturated carbon bond with the unsaturated carbon bond portion as a reaction site is subjected to addition polymerization to coat the surface of the dye precursor or the particle of the active inorganic pigment. Formed.

When the compound having an unsaturated carbon bond is added to the dispersion liquid of the dye precursor or the active inorganic pigment, the state of the dispersion liquid of the dye precursor or the active inorganic pigment and the compound having the unsaturated carbon bond is The parts are phase-separated to form separate phases, but a trace amount of the compound having an unsaturated carbon bond is dissolved in the dispersion liquid of the compound constituting the thermosensitive recording component, the dye precursor or the activity. Examples thereof include a state in which the dispersion liquid of the inorganic pigment and the compound having an unsaturated carbon bond are not dissolved at all and completely phase-separated, and a state in which the compound having an unsaturated carbon bond is completely dissolved in the dispersion liquid. Among these states, most of the dye precursor or the dispersion liquid of the active inorganic pigment and the compound having an unsaturated carbon bond are phase-separated to form separate phases. A state in which an extremely small amount is dissolved in the dispersion liquid of the compound constituting the heat-sensitive recording component can be particularly preferably used for forming the color-regulating layer on the surface of the dye precursor or the particles of the active inorganic pigment. This state also includes a state in which a compound having an unsaturated carbon bond is suspended in a dispersion liquid and an extremely small amount is dissolved. Most of the compound having an unsaturated carbon bond and the dispersion of the dye precursor or the active inorganic pigment form a separate phase, and a very small amount of the compound having an unsaturated carbon bond forms a dye precursor. When a compound having an unsaturated carbon bond is polymerized in the state of being dissolved in the dispersion of the body or the active inorganic pigment, the surface of the dye precursor or the particle of the active inorganic pigment is compared with the case where the compound is polymerized in other states. As a result, it is possible to form a color-regulating layer that is uniform, dense, and excellent in various characteristics.

In a state where the dispersion liquid of the dye precursor or the active inorganic pigment and the compound having the unsaturated carbon bond are not dissolved at all and are completely phase-separated, the coloring is adjusted on the surface of the particles of the dye precursor or the active inorganic pigment. It is not preferable because it is difficult to form a layer. Further, the dye precursor or the active inorganic pigment dispersion and the compound having an unsaturated carbon bond are completely dissolved, and the dye precursor or the active inorganic pigment is dissolved and / or
Even when it swells, it is difficult to form a color-developing layer on the surface of the particles of the compound constituting the heat-sensitive recording component, which is not preferable.

Although most of the dye precursor or the dispersion of the active inorganic pigment and the compound having an unsaturated carbon bond are phase-separated to form separate layers, a very small amount of the compound having an unsaturated carbon bond is present. The state of being dissolved in the dispersion liquid of the compound constituting the thermosensitive recording component, the kind of the dispersion medium in which the particles of the dye precursor or the active inorganic pigment are dispersed, the kind of the compound having an unsaturated carbon bond may be appropriately selected. Can be realized by

As the polymerization initiator added for polymerizing the compound having an unsaturated carbon bond, known ones can be used, and the polymerization reaction mode can be radical polymerization, anion polymerization,
Although it is not particularly limited such as cationic polymerization, radical polymerization is particularly preferably used. Further, during the polymerization, the system may be heated if necessary. Specific examples of the radical polymerization initiator are shown below.

Hydrogen peroxide, cumene hydroperoxide,
t-butyl hydroperoxide, dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide,
Peroxides such as lauroyl peroxide, potassium persulfate, persulfates such as ammonium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2 , 2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2 '
-Azobis (2-methylpropionamidine) dihydrochloride, azo compounds such as 4,4'-azobis (4-cyanovaleric acid), combination of hydrogen peroxide and ferrous salt,
Redox initiation of combinations of persulfate and sodium acid sulfite, cumene hydroxyperoxide and ferrous salt, benzoyl peroxide and diethylaniline, peroxide and metal alkyl, oxygen and organometal alkyl. Agents and the like. These are not limited to being used alone, but may be used as a mixture.

The polymerization initiator for radical polymerization is not particularly limited as long as it can generate active radicals by heat or light energy other than the above-mentioned ones.

Although most of the dye precursor or the dispersion of the active inorganic pigment and the compound having an unsaturated carbon bond are phase-separated to form separate layers, a very small amount of the compound having an unsaturated carbon bond is present. When the color-developing layer is formed on the surface of the particles of the compound constituting the heat-sensitive recording component while being dissolved in the dispersion liquid of the compound constituting the heat-sensitive recording component, the polymerization initiator constitutes the heat-sensitive recording component. What dissolves in the dispersion medium in which the compound is dispersed is particularly preferably used. By using such a polymerization initiator, it is possible to prevent the particles of the compound constituting the heat-sensitive recording component from aggregating and forming coarse particles.

The compound having an unsaturated carbon bond used for forming the color-regulating layer according to the present invention has one carbon-carbon double bond and / or carbon-carbon triple bond as an unsaturated carbon bond in one molecule. It is a compound which has three or more carbon atoms, and whose unsaturated carbon bond serves as an active site and undergoes addition polymerization. Specific examples thereof are shown below.

Styrene, α-methylstyrene, α-methoxystyrene, m-bromostyrene, m-chlorostyrene, o-bromostyrene, o-chlorostyrene, p-bromostyrene, p-chlorostyrene, p-methylstyrene, p-methoxystyrene, 2-vinylpyridine, isobutene, 3-methyl-1-butene, butyl vinyl ether, methyl vinyl ketone, nitroethylene, vinylidene cyanide, ethylene, propylene, vinyl chloride, vinyl acetate, acrolein, methyl acrolein, acrylamide. , N-methylol acrylamide, N, N-dimethyl acrylamide, diacetone acrylamide, N-octadecyl acrylamide, ethyl α-acetoxyacrylate, ethyl α-chloroacrylate, methyl α-chloroacrylate, α-cis Methyl noacrylate, methyl α-phenylacrylate, benzyl acrylate, butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, tridecyl acrylate, 2-hydroxyethyl acrylate , 2-hydroxypropyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, ethoxyethoxyethyl acrylate, methyl triglycol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, cyanoethyl acrylate , Ferrocenylmethyl acrylate, glycidyl acrylate, heptafluorobutyl acrylate, methyl acrylate, octyl acrylate, methyl trifluoroacrylate, 2-chloroethyl acrylate , 2-nitrobutyl acrylate, acrylic acid, α-bromoacrylic acid, 2-hydroxyethylacryloyl phosphate, acrylonitrile, allyl glycidyl ether, allyl acetic acid, allyl alcohol, allylbenzene, N-allyl stearylamide, 1-butene, 2 -Butene, N-
Vinylcaprolactam, ethyl N-vinylcarbamate, N-vinylcarbazole, crotonaldehyde, crotonic acid, 1,1-diphenylethylene, tetrafluoroethylene, diethyl fumarate, 1-hexene, 1-vinylimidazole, 1-vinyl-2. -Methylimidazole, indene, diethyl maleate, maleic anhydride,
Maleimide, methacrylamide, benzyl methacrylate, ethyl methacrylate, ferrocenyl methyl methacrylate, glycidyl methacrylate, isopropyl methacrylate, propyl methacrylate, -n-butyl methacrylate, isobutyl methacrylate, methacrylic acid-sec-
Butyl, methacrylic acid-t-butyl, methacrylic acid-2
-Ethylhexyl, cyclohexyl methacrylate, isodecyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, methyl methacrylate, phenyl methacrylate, -2-methacrylic acid
Hydroxyethyl, 2-hydroxypropyl methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, methacrylic acid , Methacryloxyethyl phosphate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, N-methylolmethacrylamide, methacrylonitrile, methacryloylacetone, 2-isopropenyl-2-oxazoline, 2-vinylquinoline, vinyl benzoate, vinyl dodecyl. Ether, vinyl ethyl sulfoxide, vinyl formate, vinyl isobutyl ether, vinyl laurate, vinyl phenyl ether, acetyl Emissions, phenylacetylene,

Polyethylene glycol diacrylates such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, octaethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate Polyethylene glycol dimethacrylates such as methacrylate and tetraethylene glycol dimethacrylate, 2,
2,2-bis (4-acryloxyethoxyphenyl) propane, 2,2-bis (4-acryloxydiethoxyphenyl) propane, 2,2-bis (4-acryloxytriethoxyphenyl) propane, etc. Bis (4-acryloxypolyethoxyphenyl) propanes, 2,2
2,2-bis such as -bis (4-methacryloxyethoxyphenyl) propane, 2,2-bis (4-methacryloxydiethoxyphenyl) propane, 2,2-bis (4-methacryloxytriethoxyphenyl) propane (4
-Methacryloxypolyethoxyphenyl) propanes,
Allyl acrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,
5-pentanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, polypropylene glycol diacrylate, N, N'-methylenebisacrylamide, allyl methacrylate, 1,3-butanediol dimethacrylate, neopentyl Glycol dimethacrylate, 1,6
-Hexanediol dimethacrylate, dipropylene glycol dimethacrylate, diallyl phthalate, diallyl chlorendate, butadiene, ethyl butadiene-1-carboxylate, diethyl butadiene-1,4-dicarboxylate, diallyl melamine, diallyl phthalate, N, N
-Divinylaniline, divinylether, divinylbenzene, divinylnaphthalene, 1,3-butanediol dimethacrylate, isoprene,

Pentaerythritol triacrylate,
Trimethylolpropane triacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate,

Examples thereof include tetramethylolmethane tetraacrylate and tetramethylolmethane tetramethacrylate, but the present invention is not limited thereto. Moreover, these can be used individually or in mixture of 2 or more types.

The compound having an unsaturated carbon bond is preferably selected as appropriate for the purpose of adjusting the characteristics of the color forming adjustment layer. By selecting a compound having an unsaturated carbon bond, it is possible to control the thermal characteristics of the color formation adjusting layer during heating. As a method of controlling the thermal characteristics of the color forming control layer, a compound having two or more unsaturated carbon bonds in one molecule is used as a compound having an unsaturated carbon bond, and the content of such a compound is adjusted. Method etc. are mentioned.

The ratio of the compound having an unsaturated carbon bond to the dye precursor or the active inorganic pigment is preferably 3 to 500% by weight. When the ratio of the compound having an unsaturated carbon bond is smaller than this, the function as a color forming control layer becomes insufficient, and when the ratio of the compound having an unsaturated carbon bond is larger than this, the color development of the heat-sensitive recording component becomes insufficient. Become.

The dispersion liquid of the dye precursor and the active inorganic pigment used in the present invention is prepared by dry-milling the dye precursor or the active inorganic pigment to disperse it in the dispersion medium, or the dye precursor or the active inorganic pigment in the dispersion medium. It is obtained by a method of mixing and wet pulverizing. Any method can be used as a pulverizing method. The particle size of the infectious agent precursor or the active inorganic pigment in the dispersion liquid of the dye precursor or the active inorganic pigment is 20 μm.
The following is preferable, and if the particle size is larger than this, uniform printing cannot be performed, which is not preferable. The particle size is particularly preferably 10 μm or less, and more uniform printing can be obtained. Further, the lower limit of the particle diameter of the dye precursor or the active inorganic pigment is not particularly limited, but 0.1 μm or more is preferable from the viewpoint of easy production.

As the usually colorless or light-colored electron-donating dye precursor used in the present invention, compounds generally used for pressure-sensitive recording paper, heat-sensitive recording paper and the like can be used and are not particularly limited. Specific examples include the followings, but the present invention is not limited thereto.

3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) ) -3- (1,2-Dimethylindol-3-yl)
Phthalide, 3- (p-dimethylaminophenyl) -3-
(2-Methylindol-3-yl) phthalide, 3-
(P-Dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis (1,
2-Dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,
3-bis (9-ethylcarbazol-3-yl) -5-
Dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-
Triarylmethane compounds such as methylpyrrol-2-yl) -6-dimethylaminophthalide,

Diphenylmethane compounds such as 4,4'-bis (dimethylaminophenyl) benzhydryl benzyl ether, N-chlorophenyl leuco auramine and N-2,4,5-trichlorophenyl leuco auramine.

Rhodamine B anilinolactam, Rhodamine B p-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7-phenylflurane. Oran, 3-diethylamino-
7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7-
(3,4-dichloroanilino) fluorane, 3-diethylamino-7- (2-chloroanilino) fluorane,

3-Diethylamino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N-tolyl) amino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl- 7-anilinofluoran, 3-
(N-ethyl-N-tolyl) amino-6-methyl-7-
Phenethylfluorane, 3-diethylamino-7- (4
-Nitroanilino) fluorane, 3-dibutylamino-
6-methyl-7-anilinofluorane, 3- (N-methyl-N-propyl) amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isoamyl) amino-6- Methyl-7-anilinofluorane, 3- (N-
Methyl-N-cyclohexyl) amino-6-methyl-7
-Xanthene compounds such as anilinofluorane, 3- (N-ethyl-N-tetrahydrofuryl) amino-6-methyl-7-anilinofluorane,

Thiazine compounds such as benzoyl leuco methylene blue and p-nitrobenzoyl leuco methylene blue,

3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran,
Examples thereof include spiro compounds such as 3-methylnaphtho- (3-methoxybenzo) spiropyran and 3-propylspirobenzopyran. These may be used alone or in combination of two or more.

The active inorganic pigments which develop the usually colorless or light-colored electron-donating dye precursors have the ability to develop the electron-donating dye precursors among the inorganic pigments, and examples thereof include silica-alumina and silica- Magnesia,
Bentonite, kaolin, frass earth, acid clay,
Silicates such as activated clay, montmorillonite, attapulgite, zeolite, etc., whose activity is increased by subjecting these silicates to acid treatment, zinc oxide, titanium oxide, calcium sulfate, aluminum sulfate, aluminum chloride, lead chloride, tin chloride, Inorganic salts such as arsenous acid may be mentioned. Among these active inorganic pigments, the ability to color the electron-donating dye precursor varies depending on the type, those having high color density and high color development rate are preferably used, and silicates and acid treated products of silicates are particularly preferable. The active inorganic pigments can be used alone or in combination of two or more.

The thermosensitive recording material of the present invention is prepared by providing a thermosensitive recording layer on a support. The method of providing the heat-sensitive recording layer on the support is not particularly limited, but a method of applying a coating liquid containing the components of the heat-sensitive recording layer, a method of printing an ink containing the components of the heat-sensitive recording layer, etc. may be used. it can.

If desired, the heat-sensitive recording layer may contain a binder. The binder to be contained in the heat-sensitive recording layer is not particularly limited, but those having little influence on the color forming characteristics of the heat-sensitive recording component are particularly preferably used.

Specific examples of the binder include starches, hydroxyethyl cellulose, methyl cellulose,
Ethyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, polymethacrylic acid ester, sodium polyacrylate, polyethylene terephthalate, polybutylene terephthalate, chlorinated polyether , Allyl resin, furan resin, ketone resin, oxybenzoyl polyester, polyacetal, polyether ether ketone, polyether sulfone, polyimide, polyamide, polyamideimide, polyaminobismaleimide, polymethylpentene, polyphenylene oxide, polyphenylene sulfide, polyphenylene sulfone, polysulfone , Polyarylate, polyallyl sulfone, polybutadiene, polycarbo , Polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyurethane, phenol resin, urea resin, melamine resin, melamine formalin resin, benzoguanamine resin, bismaleimide triazine resin, alkyd resin, amino resin, Epoxy resin, unsaturated polyester resin, styrene / butadiene copolymer,
Acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer Examples thereof include alkali salts of styrene / maleic anhydride copolymers, alkali salts or ammonium salts of ethylene / maleic anhydride copolymers, and various other polyolefin resins.
A mixture of two or more species can be used.

The support provided with the heat-sensitive recording layer according to the present invention may be transparent, semi-transparent or opaque.
Paper, various non-woven fabrics, woven fabrics, synthetic resin films, synthetic resin laminated papers, synthetic papers, metal foils, ceramic papers, glass plates, etc., or a composite sheet combining these can be arbitrarily used according to the purpose, It is not limited to these.

In the heat-sensitive recording material of the present invention, one or more protective layers may be provided on the heat-sensitive recording layer directly or via another layer. The components of the protective layer are not particularly limited, but those which have little influence on the color forming properties of the heat-sensitive recording composition are particularly preferably used.

Specific examples of the resin used for forming the protective layer include starches, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, poly Acrylic ester, polymethacrylic acid ester, sodium polyacrylate, polyethylene terephthalate, polybutylene terephthalate, chlorinated polyether, allyl resin, furan resin, ketone resin, oxybenzoyl polyester, polyacetal, polyether ether ketone, polyether sulfone, Polyimide, polyamide, polyamideimide, polyamino bismaleimide, polymethylpentene, polyphenylene oxide, polyphenylene Nsurufido, polyphenylene sulfone, polysulfone, polyarylate, polyallyl sulfone, polybutadiene, polycarbonate, polyethylene, polypropylene, polystyrene, polyvinyl chloride,
Polyvinylidene chloride, polyvinyl acetate, polyurethane,
Phenol resin, urea resin, melamine resin, melamine formalin resin, benzoguanamine resin, bismaleimide triazine resin, alkyd resin, amino resin, epoxy resin, unsaturated polyester resin, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer,
Methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer Examples thereof include alkali salts of polymers, alkali salts or ammonium salts of ethylene / maleic anhydride copolymers, and various other polyolefin resins. These can be used alone or in combination of two or more.

In the heat-sensitive recording material of the present invention, an intermediate layer may be provided between the heat-sensitive recording layer and the support in order to improve smoothness and heat insulation. Various resins for the intermediate layer,
Organic pigments, inorganic pigments, various hollow particles, etc. can be contained.

In the heat-sensitive recording material of the present invention, the layer between the heat-sensitive recording layer and the support and / or the surface on which the heat-sensitive recording layer is provided or on the opposite side is electrically, magnetically or optically. A layer containing a material capable of recording information may be provided. Further, a back coat layer may be provided on the surface opposite to the surface on which the thermosensitive recording layer is provided for the purpose of preventing curling or antistatic, and may further be subjected to an adhesive treatment. Further, printing with UV ink or the like may be performed on the surface of the thermal recording layer or the protective layer.

In the heat-sensitive recording material of the present invention, a photothermal conversion material can be contained in any layer and support of the heat-sensitive recording material in order to carry out printing with a laser beam.

In any layer of the heat-sensitive recording material of the present invention, if necessary, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, Inorganic and organic pigments such as urea-formalin resin, etc.,
Higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, oxidized paraffin, polyethylene, oxidized polyethylene, stearic acid amide and castor wax, dispersants such as sodium dioctylsulfosuccinate, and surface active agents. Agents, fluorescent dyes and the like can also be included.

Further, an antioxidant and an ultraviolet absorber may be added for the purpose of improving light resistance. Examples of antioxidants include, but are not limited to, hindered amine-based antioxidants, hindered phenol-based antioxidants, sulfide-based antioxidants, and the like. Further, examples of the ultraviolet absorber, benzotriazole-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, organic ultraviolet absorbers such as benzophenone-based ultraviolet absorbers, and zinc oxide,
Examples thereof include inorganic ultraviolet absorbers such as titanium oxide and cerium oxide, but are not particularly limited.

[0046]

The present invention will be described in more detail with reference to the following examples. The following parts are parts by weight and% means% by weight.

Example 1 3-dibutylamino-6- which is an electron donating dye precursor
3 parts of methyl-7-anilinofluorane was crushed with a ball mill together with 54 parts of a 2.5% aqueous solution of polyvinyl alcohol to give a volume average particle size of 1 μm. This liquid was transferred to a polymerization vessel, 1.5 parts of methyl methacrylate was added, and the temperature was raised to 70 ° C. with stirring. To this was added 1.5 parts of a 2.5% aqueous potassium persulfate solution, which was a polymerization initiator, and the mixture was reacted for 8 hours while continuing stirring. Then, this was cooled to room temperature to obtain 60 parts of a dispersion liquid of electron-donating dye precursor particles having a color-developing layer on the surface. Next, 9 parts of an acid clay pigment (Shilton DR-1 manufactured by Mizusawa Chemical Industry Co., Ltd.), which is an active inorganic pigment, was pulverized with a homogenizer together with 72 parts of a 2.5% aqueous polyvinyl alcohol solution, and 9 parts of water was added to the active inorganic pigment. 90 parts of a dispersion liquid of Further, 9 parts of 2-benzyloxynaphthalene was added to a 2% aqueous solution of polyvinyl alcohol 21
2 with a volume average particle size of 1 μm
30 parts of a benzyloxynaphthalene dispersion was obtained. Further, 9 parts of calcium carbonate (Unibar 70 manufactured by Shiraishi Kogyo Co., Ltd.) was pulverized together with 21 parts of a 2% sodium hexametaphosphate aqueous solution by a homogenizer to obtain 30 parts of a calcium carbonate dispersion liquid. The above-mentioned four kinds of dispersion liquids were mixed to prepare a coating liquid for the heat-sensitive recording material. This coating solution was applied on a polyethylene terephthalate (PET) sheet having a thickness of 100 μm so that the amount of solid content applied was 5.5 g / m ^2, and dried in an oven at 60 ° C. to prepare a heat-sensitive recording material.

Example 2 3-dibutylamino-6-, an electron-donating dye precursor
3 parts of methyl-7-anilinofluorane was crushed with a ball mill together with 54 parts of a 2.5% aqueous solution of polyvinyl alcohol to give a volume average particle size of 1 μm. Transfer this solution to a polymerization vessel, add 1 part of methyl methacrylate, and stir to 70
The temperature was raised to ° C. To this was added 1 part of a 2.5% aqueous potassium persulfate solution and 1 part of water as a polymerization initiator, and the reaction was continued for 8 hours while continuing stirring. Then it is cooled to room temperature,
60 parts of a dispersion liquid of electron-donating dye precursor particles having a color-developing layer on the surface was obtained. Next, 9 parts of an acid clay pigment (Shilton DR-1 manufactured by Mizusawa Chemical Industry Co., Ltd.), which is an active inorganic pigment, was pulverized with 72 parts of a 2.5% aqueous polyvinyl alcohol solution by a homogenizer. Transfer this liquid to a polymerization vessel,
3 parts of methyl methacrylate was added and the temperature was raised to 70 ° C. with stirring. To this, 3 parts of 2.5% potassium persulfate aqueous solution and 3 parts of water, which is a polymerization initiator, were added, and while stirring was continued,
Reacted for hours. Next, this was cooled to room temperature to obtain 90 parts of a dispersion liquid of active inorganic pigment particles having a color development adjusting layer on the surface. In addition, 2 parts of 2-benzyloxynaphthalene 9 parts
The mixture was pulverized with a ball mill together with 21 parts of a polyvinyl alcohol aqueous solution to obtain 30 parts of a 2-benzyloxynaphthalene dispersion having a volume average particle size of 1 μm. Further, 9 parts of calcium carbonate (Unibar 70 manufactured by Shiraishi Kogyo Co., Ltd.) was pulverized together with 21 parts of a 2% sodium hexametaphosphate aqueous solution by a homogenizer to obtain 30 parts of a calcium carbonate dispersion liquid. The above-mentioned four kinds of dispersion liquids were mixed to prepare a coating liquid for the heat-sensitive recording material. This coating solution was applied to a polyethylene terephthalate (PET) sheet having a thickness of 100 μm so that the amount of solid content applied was 5.5 g / m ^2, and dried in an oven at 60 ° C. to prepare a heat-sensitive recording material.

Example 3 3-Dibutylamino-6- which is an electron donating dye precursor
3 parts of methyl-7-anilinofluorane was pulverized by a ball mill together with 54 parts of a 2.5% polyvinyl alcohol aqueous solution, and further 3 parts of water was added to obtain 60 parts of a dye precursor dispersion having a volume average particle diameter of 1 μm. Then, an acid clay pigment (Silton DR-1 manufactured by Mizusawa Chemical Industry Co., Ltd.) 9 which is an active inorganic pigment
A part was pulverized with 72 parts of a 2.5% aqueous solution of polyvinyl alcohol by a homogenizer. Transfer this solution to a polymerization vessel, add 4.5 parts of methyl methacrylate, and stir it with stirring.
The temperature was raised to 0 ° C. To this was added 4.5 parts of a 2.5% aqueous solution of potassium persulfate as a polymerization initiator, and the reaction was carried out for 8 hours while continuing stirring. Next, this was cooled to room temperature to obtain 90 parts of a dispersion liquid of active inorganic pigment particles having a color development adjusting layer on the surface. In addition, 2 parts of 2-benzyloxynaphthalene was added to 2 parts.
% Polyvinyl alcohol aqueous solution together with a ball mill to obtain 30 parts of 2-benzyloxynaphthalene dispersion having a volume average particle size of 1 μm. Further, 9 parts of calcium carbonate (Unibar 70 manufactured by Shiraishi Kogyo Co., Ltd.) was pulverized together with 21 parts of a 2% sodium hexametaphosphate aqueous solution by a homogenizer to obtain 30 parts of a calcium carbonate dispersion liquid. The above-mentioned four kinds of dispersion liquids were mixed to prepare a coating liquid for the heat-sensitive recording material. This coating solution was applied on a polyethylene terephthalate (PET) sheet having a thickness of 100 μm so that the amount of solid content applied was 5.5 g / m ^2, and dried in an oven at 60 ° C. to prepare a heat-sensitive recording material.

Example 4 Example 1 was repeated except that synthetic silica (Silicia 470 manufactured by Fuji Silysia Chemical) was used in place of the acid clay pigment (Shilton DR-1 manufactured by Mizusawa Chemical Co., Ltd.) used in Example 1.
A thermal recording material was prepared in the same manner as in.

Comparative Example 1 3-dibutylamino-6- which is an electron-donating dye precursor
3 parts of methyl-7-anilinofluorane was pulverized by a ball mill together with 54 parts of a 2.5% polyvinyl alcohol aqueous solution, and further 3 parts of water was added to obtain 60 parts of a dye precursor dispersion having a volume average particle diameter of 1 μm. Then, an acid clay pigment that is an active inorganic pigment (Shilton DR-1 manufactured by Mizusawa Chemical Industry Co., Ltd.)
9 parts of water was pulverized with a homogenizer together with 72 parts of a 2.5% polyvinyl alcohol aqueous solution, and 9 parts of water was added to obtain 90 parts of an active inorganic pigment dispersion liquid. Further, 9 parts of 2-benzyloxynaphthalene was added to a 2% aqueous solution of polyvinyl alcohol 2
It was crushed together with 1 part by a ball mill to obtain 30 parts of a 2-benzyloxynaphthalene dispersion liquid having a volume average particle size of 1 μm. Furthermore, calcium carbonate (Univer 70, Shiraishi Kogyo) 9
Parts were pulverized together with 21 parts of a 2% sodium hexametaphosphate aqueous solution with a homogenizer to obtain 30 parts of a calcium carbonate dispersion having a volume average particle size of 1 μm. The above-mentioned four kinds of dispersion liquids were mixed to prepare a coating liquid for the heat-sensitive recording material. This coating solution was applied on a polyethylene terephthalate (PET) sheet having a thickness of 100 μm so that the amount of solid content applied was 5.5 g / m ^2, and dried in an oven at 60 ° C. to prepare a heat-sensitive recording material.

Comparative Example 2 Instead of the acid clay pigment (Shilton DR-1 manufactured by Mizusawa Chemical Co., Ltd.) used in Example 1, 3,3'-diallyl-
A thermal recording material was prepared in the same manner as in Example 1 except that 4,4'-dihydroxydiphenyl sulfone was used.

Comparative Example 3 Instead of the acid clay pigment (Shilton DR-1 manufactured by Mizusawa Chemical Co., Ltd.) used in Example 2, 3,3'-diallyl-
A thermal recording material was prepared in the same manner as in Example 1 except that 4,4'-dihydroxydiphenyl sulfone was used.

Test 1 Printing with Thermal Head The thermal recording materials of Examples 1 to 4 and the thermal recording materials of Comparative Examples 1 to 3 were equipped with a TDK printing head (LH4409) and a thermal facsimile printing tester (TH-PMD) manufactured by Okura Electric. )
Was applied with an applied voltage of 20 V and an applied pulse of 2.0 ms. The positions of the filter holes were measured in black using a densitometer (Macbeth RD918) for the densities of the printed part and the background part. The results are shown in Table 1.

Test 2 Image stability test (moisture and heat resistance) The thermal recording materials of Examples 1 to 4 and the thermal recording materials of Comparative Examples 1 to 3 were equipped with a TDK print head (LH4409) and manufactured by Okura Denki Thermal Printing Machine. (TH-PMD)
Was applied with an applied voltage of 20 V and an applied pulse of 2.0 ms. This printed part is at a temperature of 50 ° C and a relative humidity of 9
After left in a 0% environment for 1 week, the density was measured with a densitometer (Macbeth RD918) in black for the positions of the filter holes. The results are shown in Table 1.

Test 3 Image Stability Test (Oil Resistance) The thermal recording materials of Examples 1 to 4 and the thermal recording materials of Comparative Examples 1 to 3 were equipped with a print head (LH4409) made by TDK, and a thermal facsimile printing tester made by Okura Electric Co., Ltd. (TH-PMD)
Was applied with an applied voltage of 20 V and an applied pulse of 2.0 ms. Castor oil was applied to the printed portion, spread, and allowed to stand for 24 hours, and the bleeding state of the printed image was visually observed. In addition, the concentration is measured by a densitometer (Macbeth RD9
18) was used to measure the position of the filter hole in black. The results are shown in Table 2.

[0057]

[Table 1]

[0058]

[Table 2]

In Table 2, in Examples 1 to 4, the visibility of the image was very good because the whiteness of the background portion was high and there was no bleeding of the image. In Comparative Example 1, there was no blurring of the image, but the visibility of the image was poor because the whiteness of the background part was low. In Comparative Examples 2 and 3, the image was blurred and the image density was lowered, so the visibility of the image was poor.

[0060]

As is clear from Tables 1 and 2, Examples 1 to 1
With the heat-sensitive recording material of 4, the whiteness of the background is good, the stability of the color-developed part is high, the image is hard to be erased especially when oil is attached, and the color-developed material is hard to dissolve in the oil. It was possible to obtain a heat-sensitive recording material that is difficult to see.

Continuation of front page (56) Reference JP-A-7-304260 (JP, A) JP-A-6-143822 (JP, A) JP-A-5-24362 (JP, A) JP-A-3-61585 (JP , A) JP 63-141785 (JP, A) JP 63-115787 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41M 5 / 28-5 / 34

Claims (2)

(57) [Claims] 1. A heat-sensitive recording material comprising a support having thereon a heat-sensitive recording layer mainly containing a heat-sensitive recording component which reacts with heat to develop a color, wherein the heat-sensitive recording component is usually a colorless or light-colored electron-donating dye precursor. , And an active inorganic pigment that causes the dye precursor to develop color, and at least one of the usually colorless to light-colored electron-donating dye precursor, or the active inorganic pigment that causes the dye precursor to develop color,
A heat-sensitive recording material, which is contained in the heat-sensitive recording layer in the form of particles provided with a color-forming control layer obtained by polymerizing a compound having an unsaturated carbon bond on the surface. 2. The coloring control layer comprises a compound having an unsaturated carbon bond, which is added to a dispersion liquid of a generally colorless to light-colored electron-donating dye precursor or an active inorganic pigment that causes the dye precursor to form a color. 2. The heat-sensitive recording material according to claim 1, wherein the compound having a carbon bond is obtained by addition-polymerizing an unsaturated carbon bond portion as a reaction site to coat the surface of the particle.