JP2000160060A - Oil-in-water emulsion of energy ray-curable resin composition and heat sensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin composition excellent in recording-running properties and shelf stability of a heat sensitive recording medium before and after color development, suitable for forming a heat sensitive recording medium having high gloss and high grade feeling and excellent in workability and environmental safety by compounding a resin bearing an ethylenically unsaturated group in the molecule, two kinds of hydrophilic resin having different molecular structures and a filler. SOLUTION: The emulsion is an oil-in-water emulsion of an energy ray- curable resin composition comprising a resin (A) bearing an ethylenically unsaturated group in the molecule, a hydrophilic resin (B) represented by formula I or II (wherein R is H or a 1-25C alkyl; and (n) is a number of at least 1 on the average), a hydrophilic resin (C) bearing an ethylenically unsaturated group and an ammonium sulfonate salt group in the molecule, and a filler (D). The components A, B, C and D are employed desirably in a weight ratio of 2-80%, 8-20%, 0.7-3% and 5-30%, respectively, based on the whole composition. The hydrophilic resin C is represented, for example, by formula III.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-in-water emulsion of an energy ray-curable resin composition and a thermosensitive recording medium having a cured film layer of the energy ray-curable resin composition as an overcoat layer. More specifically, an energy ray excellent in recording runnability, preservability of the heat-sensitive recording medium before and after coloring, and suitable for forming a high-grade heat-sensitive recording medium provided with gloss, and excellent in workability and environmental security. The present invention relates to an oil-in-water emulsion of a curable resin composition and a thermosensitive recording medium obtained by applying the emulsion.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive recording medium for obtaining a recorded image by reacting a colorless or light-colored leuco dye with an organic or inorganic developer by heat is relatively inexpensive, the apparatus is compact and maintenance-free. For this reason, it has rapidly spread in the field of facsimile and printers in recent years, and its fields of use, such as POS labels, overhead projectors (OHP), second original drawings, cards, and the like, are also expanding.

However, the conventional heat-sensitive recording medium has a problem in storage stability (especially, fading of a color-developed image by a plasticizer, oil, and water) and has a drawback such as background fogging. As a method for solving this problem, a method of providing an energy ray-curable resin layer on a heat-sensitive layer (Japanese Patent Publication No. 58-35478) or a method of providing an energy-ray-curable resin layer on a heat-sensitive layer via an intermediate layer. There has been proposed a method of obtaining a heat-sensitive recording material having excellent storage properties and recording characteristics without fogging (Japanese Patent Laid-Open No. 59-26291).

[0004]

However, with the recent diversification and high performance of thermal recording systems, hardware such as thermal printers and facsimile machines have made remarkable progress. Even though the energy ray-curable resin is overcoated, there are problems such as adhesion of debris to the thermal head and generation of sound during printing (sticking noise), and a good thermal recording medium has not been obtained. Also, a method using a resin having a Tg point of 200 ° C. or higher as an energy ray-curable resin (Japanese Patent Laid-Open Publication
-125277) and a method of adding a pigment of 15 microns or less to the resin (Japanese Patent Application Laid-Open No. 1-210381) have been proposed, but all of them have excellent high-speed recording characteristics.
Further, the object of obtaining a heat-sensitive recording material having high gloss and excellent storage stability of a color-developed image per se has not yet been achieved.

[0005] Energy ray-curable resins are used in many fields because of their simple curing equipment and good productivity. However, due to problems in handling and coating, reactive diluents and organic solvents are used. Must be used in many cases, and the composition has problems in workability and safety in terms of skin irritation, odor, and toxicity. As a means for solving this problem, there is an emulsion of an energy ray-curable resin (Japanese Patent Application Laid-Open No. Sho 50-7).
9533).

However, when an emulsifier which is usually used for emulsification is used, the preservability of the heat-sensitive recording material such as water resistance and the recording characteristics at the time of printing deteriorate due to the effect of the emulsifier remaining on the cured film. There's a problem. In addition, when used for printing with a high-speed printer, overcoating with a coating solution in which only the energy-ray-curable resin is emulsified results in insufficient recording characteristics. In such a case, it is necessary to add an inorganic or organic filler. As the method, there is a method of preparing an emulsion by dispersing an inorganic or organic filler in the resin before emulsifying the energy ray-curable resin and emulsifying and dispersing the filler in water. However, in such a case, when an inorganic or organic filler is filled, the stability of the oil-in-water emulsion is reduced, and thus the production of the emulsion is difficult, and the gloss of the coating film of the overcoat layer using such an emulsion is reduced. And so on. As a method for solving such a problem, the present inventors have previously proposed an oil-in-water type radiation-curable resin emulsion composition suitable for a protective layer of a thermosensitive recording medium (Japanese Patent Laid-Open No. 5-31892).
5). However, this method also has insufficient points such as stability of the emulsion and printing performance corresponding to recent high performance of the printer.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention provides (1) a resin (A) having an ethylenically unsaturated group in a molecule, and a compound represented by the formula (1) or the formula (2):

Embedded image (In the formulas (1) and (2), R is a hydrogen atom or a group having 1 to 1 carbon atoms.
In 25 alkyl groups, n represents a number of 1 or more on average. ), A hydrophilic resin (C) having an ethylenically unsaturated group and an ammonium sulfonate group in the molecule, and an energy ray-curable resin containing a filler (D) as an essential component. An oil-in-water emulsion of the resin composition, (2) the energy ray-curable resin composition according to (1), wherein the hydrophilic resin (C) is a resin having a phenol residue and a (poly) ethylene oxide chain in a molecule. (3) The energy ray-curable resin composition according to (2), wherein the hydrophilic resin (C) is a compound having a (poly) ethylene oxide chain between a phenol residue and an ammonium sulfonate group. (4) hydrophilic resin (C) is a compound having an ethylenically unsaturated group on a phenol residue or on a (poly) ethylene oxide chain. (2) or (3), wherein the oil-in-water emulsion of the energy ray-curable resin composition, (5) the hydrophilic resin (C) is a resin having a (poly) between a phenol residue and an ammonium sulfonate base. The energy ray-curable resin composition according to (2), which is a compound in which a group having an ethylene oxide chain and a group having a (poly) ethylene oxide chain between a phenol residue and an ethylenically unsaturated group are linked by a methylene chain. Oil-in-water emulsion,
(6) The filler (D) is an inorganic filler, and its content is 0.5 to the total solid content of the energy ray-curable resin composition.
The oil-in-water emulsion according to any one of (1) to (5), which is 滴 50% by weight, and (7) any one of (1) to (6) containing a wax (E) having a softening point of 87 to 100 ° C. The oil-in-water emulsion described in the above item, (8) an overcoating agent comprising the oil-in-water emulsion described in any one of (1) to (7), (9) a thermosensitive coloring layer on a support, A heat-sensitive recording material having an overcoat layer, wherein the overcoat layer comprises a cured film layer of the overcoat agent described in (8).

The present invention relates to a resin (A) having an ethylenically unsaturated group in the molecule, a hydrophilic resin (B) represented by the above formula (1) or (2), and an ethylenically unsaturated group in the molecule. It is an oil-in-water emulsion of an energy ray-curable resin composition containing a hydrophilic resin (C) having an unsaturated group and an ammonium sulfonate group, and a filler (D).

The resin (A) having an ethylenically unsaturated group in the molecule used in the present invention is preferably a resin which is liquid at normal temperature, for example, vinyl monomers such as styrene, vinyl acetate and N-vinylpyrrolidone, and acrylates. And acrylates are more preferable. The amount used is preferably from 2 to 80% by weight, more preferably from 10 to 60% by weight, based on the total weight of the energy ray-curable resin composition, in consideration of film properties such as film formability, coating film strength and gloss. % Range.

Acrylates are a monofunctional monomer having one acryloyl group and a bifunctional monomer having two acryloyl groups.
Functional monomers, oligomers having an acryloyl group, and polyfunctional monomers having three or four or more acryloyl groups are roughly classified into, for example, three or four or more acryloyl groups in terms of film forming ability and film hardness. Oligomers and polyfunctional monomers which are liquid at room temperature are preferable, and monofunctional monomers and bifunctional monomers are mainly used for adjusting the viscosity of the energy ray-curable resin composition.
The amount of the oligomer or polyfunctional monomer used at room temperature and having three or four or more acryloyl groups in the resin (A) having an ethylenically unsaturated group in the molecule is usually 50 to 1
00% by weight.

Examples of the polyfunctional monomer include trimethylolpropane tri (meth) acrylate, trimethyloloctanetri (meth) acrylate, trimethylolpropanepolyethoxytri (meth) acrylate, trimethylolpropanepolypropoxytri (meth) acrylate, Trimethylolpropane polyethoxypolypropoxy tri (meth) acrylate, tris [(meth)
Acroyloxyethyl] isocyanurate, pentaerythritol tri (meth) acrylate, pentaerythritol polyethoxytetra (meth) acrylate, pentaerythritol polypropoxytetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) ) Acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified tris [(meth) acryloyloxyethyl] isocyanurate and the like.

Examples of the oligomer include epoxy (meth) acrylate, polyethylene (meth) acrylate, polyether (meth) acrylate, silicon (meth) acrylate, polybutadiene (meth) acrylate, polystyrylethyl (meth) acrylate, and polyamide (meth). ) Acrylate and the like.

Examples of the bifunctional monomer include ethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, and di (meth) acrylate of an alkylene oxide adduct of bisphenol A. ,
Tetraethylene glycol diacrylate, neopentyl glycol diacrylate hydroxypivalate,
1,4-butanediol di (meth) acrylate, 1,
6-hexanediol di (meth) acrylate, 1,1
2-dodecanediol di (meth) acrylate, 1,1
4-tetradecanediol di (meth) acrylate,
1,16-hexadecanediol di (meth) acrylate, 1,20-eicosanediol di (meth) acrylate, isopentyldiol di (meth) acrylate,
3-ethyl-1,8-octanediol di (meth) acrylate and the like.

As the monofunctional monomer, for example, N, N-
Dimethylaminomethyl (meth) acrylate, N, N-
Dimethylaminoethyl (meth) acrylate, N, N-
Diethylaminoethyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxybutyl (meth) acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-decyl acrylate, isobornyl (meth) acrylate, dicyclopentanyloxy Ethyl (meth) acrylate,
Phenoxyethyl (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, nonylphenoxyethyl (meth) acrylate, lauryl (meth) acrylate, phenylglycidyl ether (meth) acrylate, acryloylmorpholine, and the like.

Formula (1) or (2) used in the present invention
The hydrophilic resin (B) having 80% by weight or more of ethylene oxide groups in the molecule is more preferable for producing an oil-in-water emulsion. In the formulas (1) and (2), R is a hydrogen atom or an alkyl group having 1 to 25 carbon atoms. When R is an alkyl group, for example, a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group,
A C1-12 alkyl group such as a nonyl group and a dodecanyl group is preferred. Also, n is preferably about 1 or more and about 400 or less as an average value, and more preferably 30 or more and 200 or less. Examples of the hydrophilic resin (B) represented by the formula (1) include, for example, Aqualon RN-50 (R =
Examples of the hydrophilic resin (B) in which the nonyl group (n = 50) is represented by the formula (2) include Adecaria Soap NE-50 (R = nonyl group, n = 50) manufactured by Asahi Denka Kogyo. No.

The amount of the hydrophilic resin (B) represented by the formula (1) or (2) depends on the stability and water resistance of the emulsion,
In consideration of film properties such as heat resistance, it is usually in the range of 4 to 30% by weight, more preferably 8 to 20% by weight, based on the total weight of the energy ray-curable resin composition.

The hydrophilic resin (C) is a kind of anionic emulsifier, but in consideration of the water resistance of the resulting film and the suitability for head matching, an ethylenically unsaturated group and an ammonium sulfonate group (-SO3NH4) are included in the molecule. Are effective. Examples of the ethylenically unsaturated group include a vinyl group, a propenyl group, and a (meth) acryloyl group.

The hydrophilic resin (C) has a phenol residue and a (poly) ethylene oxide chain in the molecule. The phenol residue may have a substituent such as an alkyl group.
The hydrophilic resin (C) has a (poly) ethylene oxide chain between a phenol residue and an ammonium sulfonate group. Further, the hydrophilic resin (C) has an ethylenically unsaturated group on a phenol residue or on a (poly) ethylene oxide chain. Further, the hydrophilic resin (C) has a (poly) ethylene oxide chain between the phenol residue and the ammonium sulfonate group, and a (poly) ethylene oxide chain between the phenol residue and the ethylenically unsaturated group. It is also a compound in which groups are linked by a methylene chain. That is, the phenol residue and the (poly) ethylene oxide chain are linked via the phenol hydroxyl group. A substituent such as an ethylenically unsaturated group such as a propenyl group or an alkyl group may be bonded to the phenol residue. The (poly) ethylene oxide chain has an ethylenically unsaturated group such as a (meth) acryloyl group or an ammonium sulfonate group bonded to the terminal. In the (poly) ethylene oxide chain to which the ammonium sulfonate group is bonded, an ethylenically unsaturated group such as an allyloxy group may be bonded to the ethylene chain bonded to the phenol residue via a methylene chain.

Examples of the hydrophilic resin (C) include Adecaria Soap SE-10N (formula (3) below) manufactured by Asahi Denka Kogyo KK and Aqualon HS manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
-20 (the following formula (4)), and a reactive emulsifier Antox MS-60 manufactured by Nippon Emulsifier Co., Ltd. Ant
ox MS-60 is a reaction product of ethylene glycol, phenol, styrene, formaldehyde, ammonium hydrogen sulfide, and methacrylic acid containing [(1-phenylethyl) phenoxypolyethoxy] ethyl methacrylate as a main component. It is considered to have the basic structure of 5).

[0020]

Embedded image

The amount of the hydrophilic resin (C) having an ethylenically unsaturated group and an ammonium sulfonate group in the molecule depends on the stability with time of the emulsion, the mechanical stability when diluted, the water resistance, the heat resistance and the heat resistance. Taking into account the film properties such as the properties, the content is usually 0.1 to the total weight of the energy ray-curable resin composition.
It is in the range of 4 to 5% by weight, more preferably 0.7 to 3% by weight.

In the present invention, a filler (D) is used. The particle size is preferably smaller than the thickness of the overcoat layer, more preferably 0.01 to 5 μm as the average particle size.
m (measurement is performed by the BET method for fine particles of 1 μm or less, for example, by the sedimentation method for particles larger than 1 μm). In addition, considering the stability of the emulsion and the gloss of the coating film, the amount used is 3 to 50% by weight, more preferably 5 to 3% by weight, based on the total weight of the energy ray-curable resin composition.
The range is 0% by weight. It is preferable to use it when using it with a printer having a high printing energy such as a high-speed printing printer.

Examples of the filler (D) include an inorganic filler and an organic filler. As the inorganic filler, for example, aluminum hydroxide, magnesium hydroxide,
Examples include inorganic powders such as calcium carbonate, magnesium carbonate, magnesium oxide, aluminum oxide, silicon dioxide, titanium dioxide, talc, clay, kaolin, colloidal silica, and metal powders, and fillers obtained by surface-treating these inorganic powders. Examples of the organic filler include styrene microballs, polystyrene resin beads, acrylic resin beads, urethane resin beads, polycarbonate resin beads, benzoguanamine-formalin condensate resin powder, benzoguanamine-melamine-formalin condensate resin powder, and urea. -Resin powder of formalin condensate, aspartic acid ester derivative, zinc stearate, amide amide, epoxy resin powder, polyethylene powder, tetrabromobisphenol A,
Decabromodiphenyl oxide, tricresyl phosphate, triethyl phosphate, aromatic polyester and the like can be mentioned. These are used alone or in combination of two or more. These fillers (D) are used mainly for the purpose of preventing adhesion of debris to the head and preventing sticking in high-speed printing, and inorganic fillers are preferable in view of heat resistance and cost.

Further, the energy ray-curable resin composition of the present invention may contain a wax (E) in order to further reduce the adhesion of scum to the thermal head.
Examples of the wax (E) include carnauba wax, paraffin wax, and synthetic wax. Examples of the wax (E) include acrylic type such as Slip Aid SL-140 (softening point 90.6 to 93.3 ° C.) manufactured by San Nopco Co., Ltd. Polymerized (polymer) waxes are preferred. Its softening point is 87-100 ° C
Degree is preferable, and about 89 to 95 ° C. is particularly preferable.
The amount of use is preferably 0 to 10% by weight, more preferably 0.01 to 5% by weight, and further preferably 0.05 to 1% by weight, based on the total weight of the energy ray-curable resin composition. % Range. If the amount is too large, problems such as a decrease in gloss occur.

The energy ray-curable resin composition used in the present invention may contain a tetrafluoride resin, a stearic acid-modified silicone oil, an aspartic acid ester derivative, if necessary, for the purpose of improving the slipperiness of the surface of the thermosensitive recording medium. , Famex A-1212 (manufactured by Ajinomoto Co.), etc., and straight-chain C16- such as zinc stearate, magnesium stearate, calcium stearate, amide stearate, polyoxyethylene stearamide, polyoxyethylene sorbite stearic ester and the like. A compound having a long-chain alkyl group of C18, liquid paraffin, vegetable oil, animal oil, sorbitan ester, polyoxyethylene sorbite fatty acid ester, and polyglycerin fatty acid ester can be added. In addition, in order to improve the leveling property of the coating liquid in addition to the slipperiness, acrylic copolymer, silicone oil, alkyl group, amino group, epoxy group,
Silicone oil modified with a fluorine group, a carboxyl group, a hydroxyl group, a mercapto group, an acrylic group, a methacryl group, or the like, a fluorine-based surfactant, or the like can be added. Also, a small amount of an emulsifying / dispersing agent can be added for the purpose of improving the emulsifying power. These can be contained alone or in combination.

The mixing ratio of these components is preferably 0.01 to 10%, more preferably 0.05 to 5%, based on the total weight of the composition.

The energy ray-curable resin composition used in the present invention may or may not be cured with an electron beam. However, when it is cured with an ultraviolet ray, a photopolymerization initiator may be used. Use an accelerator. As the photopolymerization initiator, for example, acetophenone, benzophenone, benzoin ether, chloroacetophenone, diethoxyacetophenone, hydroxyacetophenone, α-aminoacetophenone, benzylmethyl ketal, thioxanthone, α-acyl oxime ester, acyl phosphine oxide, glyoxy ester, 3-ketocoumarin, 2
-Ethylanthraquinone, camphorquinone, benzyl and the like. As photopolymerization accelerators, amine compounds such as N-methyldiethanolamine, triethanolammon, diethanolamine, isoamyl P-dimethylaminobenzoate, N, N-diethyl-P-aminobenzonitrile, and tri-n-butylphosphine Or a chlorine compound such as hexachloroethane, Michler's ketone, etc., alone or in combination of two or more. The mixing ratio of the polymerization initiator and the accelerator is preferably 0.1 to 15%, more preferably 0.5 to 10%, based on the total weight of the composition.
It is.

Further, the energy ray-curable resin composition used in the present invention may optionally contain a polymer, an antifoaming agent, an ultraviolet absorber, an antioxidant, a polymerization inhibitor, an antistatic agent, a fluorescent dye, etc. Can be used in combination by appropriately selecting the kind and the amount of use.

The emulsion of the present invention can be produced, for example, as follows. That is, the hydrophilic resin (B) represented by the formula (1) or the formula (2) and the hydrophilic resin (C) having an ethylenically unsaturated group and an ammonium sulfonate group in a molecule are dissolved or dissolved in water. Disperse. Next, a resin having an ethylenically unsaturated group in the molecule to which a photoinitiator, a photopolymerization accelerator, and other additives are added as required (A)
While the liquid is being stirred, the solution or dispersion of the hydrophilic resin (B) and the hydrophilic resin (C) is gradually added to the liquid, and a high-speed stirrer such as a homomixer or a sand mill or a microfluidizer is used. By emulsification / dispersion, an oil-in-water emulsion of the energy ray-curable resin composition of the present invention can be obtained.

The filler (D) is previously dispersed in a resin (A) having an ethylenically unsaturated group in the molecule by a disperser such as a ball mill, a roll mill, a sand mill, a dissolver and the like. A polymerization accelerator and other additives are added. As a dispersant for the filler (D), a polycarboxylic acid-based dispersant, a silane coupling agent, a titanate-based coupling agent, a silicone-based dispersant such as modified silicone oil, or an organic copolymer-based dispersant is used in combination. Is also possible. These compounding ratios are 0.01 to 10%, preferably 0.05 to 10%, based on the total weight of the composition.
~ 5% can be used. The solution or dispersion of the resin (A) having one or more ethylenically unsaturated groups in the molecule containing the filler (D) thus obtained, the hydrophilic resin (B) and the hydrophilic resin (C) is first prepared. Mixing in the manner described in
By emulsifying and dispersing, an oil-in-water emulsion of the energy ray-curable resin composition of the present invention is obtained.

When the wax (E) is used, it may be added to the resin (A) having an ethylenically unsaturated group in the molecule in advance, or a suspension of the wax (E) may be used as an energy ray-curable resin composition. May be added to the oil-in-water emulsion.

The solid content in the oil-in-water emulsion of the energy ray-curable resin composition thus obtained is 2
0 to 80% by weight, more preferably 30 to 70% by weight. The oil-in-water emulsion of the energy ray-curable resin composition is stable over time, and the emulsion diluted with water as required for coating is also stable.

As a method of forming a cured film of the oil-in-water emulsion of the energy ray-curable resin composition, bar coater coating, air knife coating, gravure coating, offset printing, flexographic printing, screen printing, etc. It is applied to paper, synthetic paper or film by a method known per se, dried, and then irradiated with energy rays such as ultraviolet rays or electron beams to cure the coating. In this case, when curing with an electron beam, an electron beam accelerator having an energy of 100 to 500 eV is preferable. On the other hand, in the case of curing with ultraviolet rays, a xenon lamp, a high-pressure mercury lamp, and an ultraviolet irradiation device having a metal halide lamp are used as the light source, and the amount of light and the arrangement of the light source are determined as necessary. ~ 120W /
using a lamp with a light intensity of 20 cm
It is preferable to cure by irradiating 1 to 4 times at m / min.

The heat-sensitive recording material of the present invention is obtained by overcoating the above-mentioned energy ray-curable resin composition as an overcoat agent on a heat-sensitive coloring layer provided on a support. In the present invention, the thermosensitive coloring layer mainly comprises a colorless or pale-colored coloring compound (leuco dye) and a color developing compound capable of developing color when heated as a main component, and comprises a binder and, if necessary, a sensitizer as shown below. , Fillers and other additives.

In forming the thermosensitive coloring layer in the present invention, the coloring compound is 1 to 50% by weight, the color developing compound is 5 to 80% by weight, the binder is 1 to 90% by weight, the filler and the heat Each of the fusible compounds (sensitizers) is 0 to 80% by weight,
In addition, a lubricant, a surfactant, an antifoaming agent, an ultraviolet absorber and the like are each used in an arbitrary ratio, for example, 0 to 30% by weight. The weight% is the weight ratio of each component in the thermosensitive coloring layer.

Examples of the coloring compound used in the thermosensitive coloring layer are not particularly limited as long as they are those generally used in pressure-sensitive recording paper or thermosensitive recording paper. Specific examples include, for example, fluoran compounds, triarylmethane compounds, spiro compounds, diphenylmethane compounds,
Thiazine compounds, lactam compounds, fluorene compounds and the like are mentioned.

As the fluoran compound, for example, 3-
Diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilino Fluoran, 3- (N
-Ethyl-N-isopentylamino) -6-methyl-7
-Anilinofluoran, 3-isobutylethylamino-
6-methyl-7-anilinofluoran, 3- [N-ethyl-N- (3-ethoxypropyl) amino] -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-
Hexylamino) -6-methyl-7-anilinofluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-propylamino)
-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tetrahydrofurylamino) -6-methyl-
7-anilinofluoran, 3-diethylamino-6-methyl-7- (p-chloroanilino) fluoran, 3-diethylamino-6-methyl-7- (p-fluoroanilino) fluoran, 3- (p-toluidine Noethylamino)
-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (p-toluidino) fluoran, 3-diethylamino-7- (o-chloroanilino)
Fluorane, 3-dibutylamino-7- (o-chloroanilino) fluoran, 3-diethylamino-7- (o-
Fluoroanilino) fluoran, 3-dibutylamino-
7- (o-fluoroanilino) fluoran, 3-diethylamino-7- (3,4-dichloroanilino) fluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro -7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-
7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7-
Methylfluoran, 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7-phenylfluoran, 3- (p-toluidinoethylamino) -6
-Methyl-7-phenethylfluoran and the like.

Examples of the tolylmethane-based compound include 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone or CVL) and 3,3-bis (p-dimethylamino). Phenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylaminoindole-
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- (2-phenylindol-3-yl) -5-dimethyl Aminophthalide, 3-p-dimethylaminophenyl-3- (1-
Methylpyrrole-2-yl) -6-dimethylaminophthalide and the like.

Examples of spiro compounds include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran,
Benzylspirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro (indoline-2,2'- Benzopyran) and the like, as diphenylmethane compounds, for example, N-halophenyl-leuco auramine,
4-bis-dimethylaminophenylbenzhydrylbenzyl ether, N-2,4,5-trichlorophenylleucouramine and the like; thiazine compounds such as benzoylleucomethylene blue and p-nitrobenzoylleucomethylene blue; Examples of the fluorene-based compound include rhodamine B anilinolactam and rhodamine B-p-chloroanilinolactam, and examples of the fluorene-based compound include 3,6-bis (dimethylamino) fluorenespiro (9,3 ′)-6. '-Dimethylaminophthalide, 3,6-bis (dimethylamino) fluorenespiro (9,3')-6'-pyrrolidinophthalide,
3-dimethylamino-6-diethylaminofluorenespiro (9,3 ')-6'-pyrrolidinophthalide and the like. These coloring compounds are used alone or in combination.

The color-developing compound is not particularly limited as long as it is generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Specific examples include, for example, α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, pt-butylphenol, p-phenylphenol, 1,1-bis (p-hydroxyphenyl)
Propane, 2,2-bis (p-hydroxyphenyl) propane (alias: bisphenol A or BPA), 2,2
-Bis (p-hydroxyphenyl) butane, 1,1-bis (p-hydroxyphenyl) cyclohexane, 4,
4'-thiobisphenol, 4,4'-cyclohexylidenediphenol, 2,2 '-(2,5-dibromo-4
-Hydroxyphenyl) propane, 4,4-isopropylidenebis (2-t-butylphenol), 2,2′-
Methylenebis (4-chloroenol), 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methoxydiphenylsulfone, 4-hydroxy-4'-ethoxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-
Butoxydiphenyl sulfone, methyl bis (4-hydroxyphenyl) acetate, bis (4-hydroxyphenyl)
Phenolic compounds such as butyl acetate, benzyl bis (4-hydroxyphenyl) acetate, 2,4-dihydroxy-2'-methoxybenzanilide, benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, 4-hydroxyphthalic acid Dibenzyl, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-
Examples include aromatic carboxylic acid derivatives such as di-t-butylsalicylic acid and 3,5-di-α-methylbenzylsalicylic acid, aromatic carboxylic acids and metal salts thereof.

Examples of the binder which can be used include, for example, methyl cellulose, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose, polyvinyl alcohol (PVA), carboxyl group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol,
Polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and derivatives thereof, casein, gelatin, water-soluble isoprene rubber, alkali salt of styrene / maleic anhydride copolymer, iso (or diiso) butylene /
Water-soluble ones such as maleic anhydride copolymer salt, styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer, polystyrene Vinyl acetate, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polystyrene, acrylic resin, acrylic / styrene resin, polyacrylate, polyester, polycarbonate, polyurethane, polybutyral, epoxy resin, furan resin, vinyl toluene resin, Rosin ester resin,
Examples include hydrophobic polymer compounds such as composite particles of colloidal silica and an acrylic copolymer, and emulsions thereof.

Examples of fillers that can be used include calcium carbonate, magnesium carbonate, magnesium oxide, silica,
White carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, acrylic resin,
There are polyolefin resin, benzoguanamine resin, melamine resin, urea-formalin resin and the like.

Examples of heat-fusible compounds that can be used include waxes such as animal and vegetable waxes and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid anilides, acetylated aromatic amines, naphthalene derivatives, and aromatic ethers. And aromatic carboxylic acid derivatives, aromatic sulfonic acid ester derivatives, carbonic acid or oxalic acid diester derivatives, biphenyl derivatives, terphenyl derivatives, etc., which are solid at ordinary temperature and have a melting point of about 70 ° C. or more can be used. This heat-fusible compound usually acts as a sensitizer for increasing the color sensitivity.

Examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax,
Paraffin oxide, polyethylene wax, polyethylene oxide and the like, as higher fatty acids, for example, stearic acid,
Examples of higher fatty acid amides such as behenic acid include stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylolbehenic acid amide, methylolstearic acid amide, methylenebisstearic acid amide, and ethylenebisstearin Acid amides and the like; higher fatty acid anilides such as stearic acid anilide and linoleic acid anilide; acetylated aromatic amines such as acetotoluide; naphthalene derivatives such as 1-benzyloxynaphthalene and 2-benzyloxynaphthalene; Benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester and the like include aromatic ethers such as 1,2-diphenoxyethane, 1,4
-Diphenoxyethane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methoxyphenoxy) ethane, 1,2-bis (3,4-dimethylphenyl) ethane, 1-phenoxy- 2- (4-chlorophenoxy) ethane, 1-phenoxy-2- (4-methoxyphenoxy) ethane and the like include aromatic carboxylic acid derivatives such as benzyl p-hydroxybenzoate,
Examples of aromatic sulfonic acid ester derivatives include benzyl p-benzyloxybenzoate and dibenzyl terephthalate, for example, p-toluenesulfonic acid phenyl ester, phenylmesitylene sulfonate,
-Methylphenyl mesitylenesulfonate and the like are carbonic acid or oxalic acid diester derivatives, for example, diphenyl carbonate, dibenzyl oxalate, dioxalate (4
-Methylbenzyl) ester, oxalic acid di (4-chlorobenzyl) ester and the like, as biphenyl derivatives,
For example, p-benzylbiphenyl, p-allyloxybiphenyl and the like are terphenyl derivatives such as m-
Terphenyl and the like are each exemplified.

Other lubricants such as zinc stearate, calcium stearate and aluminum stearate, various surfactants, defoamers, ultraviolet absorbers and the like are added as required.

Using the above materials, a thermosensitive coloring layer used in the present invention is prepared, for example, by the following method. That is, first, the color-forming compound and the color-developing compound are separately pulverized and dispersed in a dispersing machine such as a ball mill, an attritor, and a sand mill together with a binder or other additives as necessary (pulverization, When the dispersion is performed by a wet method, water is usually used as a medium) and mixed to prepare a thermosensitive coloring layer coating solution, and usually 1 to 20 g by weight on a dry basis on a support such as paper, plastic sheet, or synthetic paper. / M2 by a bar coater, a blade coater, or the like (the ratio of the color-forming compound to the color-developing compound is usually from 2: 1 to 1:10 in terms of dry weight ratio) and dried.

In the present invention, an intermediate layer may be provided between the thermosensitive coloring layer and the overcoat layer or between the thermosensitive coloring layer and the support. When an intermediate layer is provided, polyvinyl alcohol, starch, styrene / butadiene latex
A hydrophilic or water-dispersible resin such as an acrylic resin emulsion, as well as a polyester resin, a solvent-soluble resin such as a copolymer of an acrylic resin and a vinyl acetate resin as a main component, and calcium carbonate, zinc oxide, if necessary, talc,
It can be provided by applying a coating solution to which a filler such as kaolin, clay, colloidal silica and the like, and an auxiliary agent such as various surfactants are added by an ordinary method.

As a method for forming the intermediate layer, for example, a ball mill, an attritor, a hydrophilic resin, a water-dispersible resin or a solvent-soluble resin may be added together with water or other fillers and a surfactant as required. After being dispersed by a dispersing machine such as a sand mill (the resin component is usually contained in an amount of 5 to 80% of the system to be dispersed and dispersed), the coating amount is applied on the heat-sensitive recording layer obtained as described above. 2-40 g
/ M ² by bar coating, air knife coating, gravure coating, roll coating coating, and the like, and dried to form an intermediate layer.

The heat-sensitive recording material of the present invention can be prepared by the method described above.
The oil-in-water type of the present invention on the obtained thermosensitive coloring layer or intermediate layer
Emulsion is used as a bar coater
ー Coating, air knife coating, gravure coating, offset marking
Printing, flexographic printing, screen printing, etc.
Cloth, dry, and then energy rays such as ultraviolet rays and electron beams
To cure the coating film and form an overcoat layer.
Obtained by The thickness of the overcoat layer is 1
About 10 to 10 μm (weight 1 to 10 g / m ^Two) Is good
Good. When the coating is cured by an electron beam,
An electron beam accelerator having an energy of 500 eV is preferred.
New On the other hand, when using ultraviolet light,
Lamp, high-pressure mercury lamp, and metal halide lamp
An ultraviolet irradiation device is used.
The arrangement is determined, but when using a high-pressure mercury lamp, 8
Transport speed by a lamp having a light amount of 0 to 120 W / cm
20 to 60 m / min, curing 1 to 4 times
preferable.

[0050]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. still,
In the examples, parts mean parts by weight.

Example 1 Formation of a heat-sensitive recording layer A mixture having the following composition was pulverized and dispersed using a sand grinder so that the average particle size became 2 μm or less, to prepare a liquid [A] and a liquid [B], respectively. [A] solution: 3-dibutylamino-7- (o-chloroanilino) fluoran 25 parts 25% aqueous solution of PVA 20 parts water 55 parts [B] solution: 2,2-bis (p-hydroxyphenyl) propane 25 parts 25% PVA aqueous solution 20 parts Water 55 parts

Next, each of the prepared solutions was mixed at the following ratio to prepare a coating solution for the heat-sensitive coloring layer, and a white PET (Toray Lille Miller E
22) The composition was coated and dried so as to have a dry weight of about 10 g / m ² to obtain a thermosensitive coloring layer. [A] Liquid 8 parts [B] Liquid 16 parts 50% calcium carbonate dispersion 20 parts 50% carboxylated styrene / butadiene copolymer latex 6 parts Water 20 parts Formation of intermediate layer PVA 25 parts Water 74 parts Colloidal silicic acid 1 part of salt The above composition was mixed to prepare a coating solution for an intermediate layer, and 2 g of a dry coating amount was applied on the heat-sensitive recording sheet obtained in
/ M ² and dried to obtain a thermosensitive recording sheet having an intermediate layer.

Formation of Overcoat Layer Dipentaerythritol hexaacrylate 26 parts EO-modified bisphenol A / diacrylate 10 parts Photoinitiator (Irgacure 184; Ciba-Geigy) 4 parts Calcium carbonate (average particle diameter 0.5 μm or less) 4 parts Hydrophilic resin (B) (Aqualon RN-50; manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., R = nonyl group in formula (1), n = 50) 5 parts Hydrophilic resin (C) (Aqualon HS-20; manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) 1) 50 parts of water

First, calcium carbonate was prepared by adding dipentaerythritol hexaacrylate and EO-modified bisphenol A
Disperse in the diacrylate mixture, then add and mix the photoinitiator. Next, an aqueous solution in which Aqualon RN-50 and Aqualon HS-20 were dissolved was added and emulsified and dispersed to obtain an oil-in-water emulsion of the energy ray-curable resin composition of the present invention. The oil-in-water type emulsion was applied onto a heat-sensitive sheet having an intermediate layer obtained by using a bar coater so that the dry coating amount was 3 g / m 2 (thickness: 3 μm).
m), and after drying and drying, an ultraviolet irradiation device (GS ASE-2) having a high pressure mercury lamp of 80 W / cm.
0; manufactured by Nippon Battery Co., Ltd.)
The energy ray-curable resin composition was cured by irradiating it once with n to obtain a thermosensitive recording medium of the present invention.

Example 2 The water of the present invention was prepared in the same manner as in Example 1, except that in place of Aqualon RN-50, a compound of the formula (1) in which R = nonyl group and n = 80 was used. An oil emulsion and a thermosensitive recording medium were obtained.

Example 3 The water of the present invention was prepared in the same manner as in Example 1 except that the compound of the formula (2) where R = nonyl group and n = 80 was used instead of Aqualon RN-50. An oil emulsion and a thermosensitive recording medium were obtained.

Example 4 In Example 1, Aquaron HS-20 was replaced with A
An oil-in-water emulsion and a heat-sensitive recording material of the present invention were obtained in the same manner as in Example 1 except that ntox MS-60 (manufactured by Nippon Emulsifier Co., Ltd.) was used.

Example 5 An oil-in-water type of the present invention was prepared in the same manner as in Example 1, except that Adekaria Soap SE-10N (manufactured by Asahi Denka Kogyo) was used in place of Aqualon HS-20. An emulsion and a thermosensitive recording medium were obtained.

Example 6 The oil-in-water droplet of the present invention was prepared in the same manner as in Example 1 except that one part of the polymerized wax emulsion (trade name: Slip Aid SL-140, manufactured by San Nopco Co., Ltd.) was used in combination. Emulsion and a thermosensitive recording medium were obtained.

Comparative Example 1 Dipentaerythritol hexaacrylate 35 parts Trimethylolpropane triacrylate 10 parts Phenoxyhexaethylene glycol acrylate 5 parts Photoinitiator (Irgacure 184; Ciba-Geigy) 5 parts Calcium carbonate (average particle diameter 0.5 μm or less) 10 parts Antox MS-60 (manufactured by Nippon Emulsifier) 5 parts Pluronic L-64 (polyoxyethylene polyoxypropylene block copolymer; manufactured by Asahi Denka Kogyo) 1 part Water 30 parts Instead of the composition of Example 1, the above is used. An oil-in-water emulsion and a thermosensitive recording medium for comparison were obtained in the same manner as in Example 1 except that the composition was used.

Using each of the thus obtained thermosensitive recording media, printing was performed by a dot line type thermal printer (Teraoka Seiko printer) having a resistance value of 589 Ω to evaluate the recording running property. It was shown to. The following evaluation criteria were used.

[0062]

[Table 1] Table 1 Evaluation results Emulsion state Mechanical sticky head residue Gloss Stability Foaming viscosity Stability King adhesion Example 1 ◎ Medium Low ○ ○ ○ 82.3 〃 2 ◎ Medium Medium ○ ○ ○ 84.1 ３ 3 ◎ Medium Medium ○ ○ ○ 81.9 〃 4 ◎ Low Low ○ ○ ○ 83.1 ５ 5 ◎ Low Low ○ ○ ○ 83.5 〃 6 ◎ Low Low ○ ◎ ○ 80.1 Comparative Example 1 △ Medium Low ○ △ △ 84.1

(1) Evaluation of emulsion state Stability: The obtained emulsion composition was allowed to stand at room temperature, and the particle size distribution (LPA-3100 manufactured by Otsuka Electronics Co., Ltd.)
The stability was evaluated by observing the water separation state and the gloss of the coating film. A: Almost no change in particle size, liquid state, and gloss. ：: Some water separation was observed, but redispersibility was good, and there was almost no change in particle size and gloss. Δ: Redispersibility is good, but change in particle size, decrease in gloss, etc. are observed. X: Separation of an oil phase and an aqueous phase is seen. Foaming property, viscosity: appearance observation (2) Evaluation of mechanical stability The obtained emulsion composition was diluted 1: 1 with water, and processed at a high speed of 10,000 rpm / min with a homomixer.
The state of the emulsion was observed and evaluated. ：: There was no change in the state of the emulsion after the treatment. B: Aggregates were slightly observed in the emulsion after the treatment. ×: The emulsion was broken and separated after the treatment. (2) Sticking evaluation criteria A: During high-speed printing, no sound was recorded at all and recording was performed smoothly. ：: At the time of high-speed printing, recording was performed smoothly with almost no sound. Δ: Recording failure occurred very slightly during high-speed printing. X: The thermal recording medium did not run smoothly and recording failure occurred.

(3) Evaluation standard for adhesion of head scum A: During high-speed printing, there was no dirt on the head. ：: At the time of high-speed printing, there was almost no dirt on the head. Δ: The head was very slightly stained after high-speed printing. X: The head was dirty after high-speed printing.

As is evident from Table 1, the emulsion of the present invention has good stability even when a filler is added, and has a low foaming property and low viscosity and is easy to handle. When used for overcoating of a heat-sensitive recording medium, it has high gloss and good sticking and adhesion of debris to the head even during high-speed printing.

[0066]

The oil-in-water emulsion of the energy ray-curable resin composition of the present invention has low viscosity and low foamability. In addition, it can be diluted and coated with water without using an organic solvent which adversely affects the human body and the environment, and the mechanical stability of the emulsion at that time is also good. Even if a filler is added, the resulting coating film has high gloss, and by using this for overcoating of thermal recording media, it can match the thermal head during high-speed printing (sticking property, adhesion of debris to the head). ) And a high-gloss, high-grade thermal recording medium was obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C09D 129/10 B41M 5/18 101E F term (Reference) 2H026 AA07 BB01 DD12 DD32 DD48 DD55 FF11 4J011 JA06 PA02 PA90 PB22 PC08 QA03 QA13 QA22 QA24 QA27 QB05 QB15 QB16 QB18 QB19 QB25 RA11 RA14 TA03 WA01 4J038 BA212 FA012 FA221 FA222 FA272 GA01 GA13 KA08 MA08 MA10 PA07 PA17 PB11

Claims (9)

[Claims] 1. A resin (A) having an ethylenically unsaturated group in a molecule, and a resin represented by the formula (1) or the formula (2): (In the formulas (1) and (2), R is a hydrogen atom or a group having 1 to 1 carbon atoms.
25 represents an alkyl group, and n represents a number of 1 or more on average. ), A hydrophilic resin (C) having an ethylenically unsaturated group and an ammonium sulfonate group in the molecule, and an energy ray-curable resin composition containing a filler (D) Oil-in-water emulsion. 2. The oil-in-water emulsion of the energy ray-curable resin composition according to claim 1, wherein the hydrophilic resin (C) is a resin having a (poly) ethylene oxide chain in a molecule. 3. The oil-in-water droplet of the energy ray-curable resin composition according to claim 2, wherein the hydrophilic resin (C) is a compound having a (poly) ethylene oxide chain between a phenol residue and an ammonium sulfonate group. Type emulsion. 4. The energy ray-curable resin composition according to claim 2, wherein the hydrophilic resin (C) is a compound having an ethylenically unsaturated group on a phenol residue or on a (poly) ethylene oxide chain. Oil-in-water emulsion. 5. A hydrophilic resin (C) comprising a group having a (poly) ethylene oxide chain between a phenol residue and an ammonium sulfonate group and a (poly) ethylene oxide between a phenol residue and an ethylenically unsaturated group. The oil-in-water emulsion of the energy ray-curable resin composition according to claim 2, which is a compound in which a group having a chain is bonded by a methylene chain. 6. The filler according to claim 1, wherein the filler (D) is an inorganic filler, the content of which is 0.5 to 50% by weight based on the total solid content of the energy ray-curable resin composition. 2. The oil-in-water emulsion according to item 1. 7. The oil-in-water emulsion according to claim 1, which comprises a wax (E) having a softening point of 87 to 100 ° C. 8. An overcoating agent comprising the oil-in-water emulsion according to any one of claims 1 to 7. 9. A thermosensitive recording material having a thermosensitive coloring layer and an overcoat layer on a support, wherein the overcoat layer comprises a cured film layer of the overcoat agent according to claim 8. .