JPH03147887A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material improved in resistance to water and resistance to sticking and enhanced in shelf stability by a method wherein a coating agent containing a specific aqueous resin dispersion liquid, an amino curing fine particle, and a crosslinker as essential ingredients is applied on a thermal color forming layer. CONSTITUTION:A protective layer is obtained by applying a coating agent containing a specific aqueous resin dispersion liquid, an amino curing fine particle, and a crosslinker as essential ingredients. The aqueous resin dispersion liquid is obtained by emulsion polymerizing a polymerizable monomer mixture containing an organic silicon monomer having hydrolyzing group directly bonding with silicon atom and a polymerizable monomer having functional group capable of reacting with carboxyl group as essential ingredients in an aqueous medium using a reactive surfactant made of a polymer shown by a formula I as an emulsifying agent. In the formula, R1 represents 6-18 C alkyl; R2, R3, R4, R5, and R6 independently represent hydrogen atom, methyl group, carboxyl group, carboxymethyl group, or the salt thereof; X represents hydrogen, ammonium salt group, amine group, alkali metal, or alkaline earth metal; Y represents hydrocarbon group having polymerizable unsatd. group; Z represents nitrile group, or phenyl group, carboxylic amide group, or carboxylic alkyl ester group which may have substituent; (a) is an integer of 1-500; (b) is 0 or an integer of 1-100; and (c) is 0 or an integer of 1-250.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a synthetic paper-based thermal recording paper, and more particularly, to a thermal recording paper that has excellent image uniformity and stick resistance, and is also excellent in strength, water resistance, etc. It's about materials.

[Prior art] It has been known for a long time that a color reaction occurs when a basic dye and an acidic color developer are heated and melted, and an example of applying this color reaction to recording paper is in Japanese Patent Publication No. 43-4180. There are Japanese Patent Publications No. 45-14039.

Fields of use for thermal recording paper include facsimiles, barcode labels, measurement recorders, terminal printers such as word processors, automatic ticket vending machines, and instant type paper used as recording paper for CR7 screens for ultrasound diagnosis. are being replaced by silver halide photographs.

As the uses of thermal recording paper expand in this way, conventional thermal recording paper, in which only a thermal paint is coated on the support, is susceptible to printing in the image area when exposed to various plasticizers, solvents, light, water, etc. It has the disadvantage that the color of the image disappears and the non-image area develops color. A similar tendency is also observed when stored for a long period of time, and there is a demand for improvement in the storage stability of thermal recording paper.

As a method to improve these drawbacks, it has been proposed to provide a protective layer on the heat-sensitive layer.
No. 128347 discloses a method of applying an aqueous emulsion of polyethylene terephthalate, polyvinyl chloride, and polyimide resin having film-forming ability and chemical resistance onto a heat-sensitive coloring layer provided on ordinary paper. 5
No. 6-125354 discloses a method of applying a water-soluble polymer compound such as polyvinyl alcohol.

However, these methods are only effective to a certain extent in preventing decolorization of image areas or color development of non-image areas due to plasticizers and oils in the wrap film, and it is difficult to use a thermoplastic emulsion as a protective layer binder. If this happens, the thermal head's statesking resistance is insufficient, the stick noise is loud during printing, and thermal melting material adheres to the head, causing printing problems.
This has the disadvantage that the thermal head may be damaged in some cases. In addition, products coated with water-soluble polymeric substances as a protective layer are generally mixed with a water-resisting agent to maintain water resistance, but since low-temperature drying is performed to prevent color development, Water resistance is insufficient, and when water adheres to the surface, the coating film easily peels off or blocking sticking occurs.

On the other hand, sticking tends to occur when printing conditions are low. The reason for this is thought to be that the molten material is cooled and becomes easier to adhere to the head, and it is desired to develop a thermal recording paper that does not cause sticking under any conditions.

[Problems to be Solved by the Invention] An object of the present invention is to provide a heat-sensitive recording material that has improved the conventional drawbacks, that is, has good water resistance and stacking resistance, and has high storage stability.

[Means for Solving the Problems] As a result of extensive research, the present inventors have developed a synthetic paper-based heat-sensitive recording material that uses a color-forming reaction between a basic colorless dye and an acidic color developer on a heat-sensitive coloring layer. , by providing a special protective layer, the above purpose can be met with distant relatives. - This protective layer is obtained by applying a coating agent containing the following aqueous resin dispersion, amino cured fine particles, and a crosslinking agent as essential components.

Aqueous resin dispersion liquid general formula (A) (wherein, R1 represents an alkyl group having 6 to 1B carbon atoms, R
2, R3, R4, R6 and R6 each independently represent hydrogen, a methyl group, a carboxyl group or a carboxymethyl group, or a salt thereof, and X represents hydrogen, an ammonium base, an amine base, an alkali metal or an alkaline earth metal. , Y represents a hydrocarbon group having a polymerizable unsaturated group,
2 is a nitrile group or a phenyl group which may have a substituent,
Represents a carboxylic acid amide group or a carboxylic acid alkyl ester group, a is an integer of 1 to 500, and b is O or 1 to 100.
C is an integer of 0 or 1 to 250. )
An organic silicon monomer having a hydrolyzable group directly bonded to a silicon atom [hereinafter, ! A polymerizable monomer mixture containing as essential components a polymerizable monomer having a functional group capable of reacting with a carboxyl group [hereinafter referred to as J#mer (2)]. A dispersion resin obtained by emulsion polymerization in an aqueous medium.

[Function] The reactive surfactant of the general formula (A) used as an emulsifier in the present invention is a polymerizable monomer (a) having a carboxyl group and, if necessary, another polymerizable monomer (b) in a carbon number It is a polymer obtained by radical polymerization in the presence of an alkyl mercaptan of 6 to 18, and the above polymerizable carmer (
Examples of a) include unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid, itaconic acid, maleic acid,
Examples include unsaturated polycarboxylic acids such as fumaric acid, and monoesters of these unsaturated polycarboxylic acids, and one or more of these can be used. Further, other polymerizable monomers (b) include, for example, styrene,
α-methylstyrene, chlorostyrene 9 vinyltoluene, chloromethylstyrene.

Styrene derivatives such as styrene sulfonic acid or its salts; (meth)acrylamide, methylolated (meth)acrylamide, alkoxymethylolated (meth)acrylamide having 1 to 4 carbon atoms.

Amide group-containing monomers such as N,N-dimethylaminoethyl (meth)acrylamide and N,N-dimethylaminopropyl (meth)acrylamide; (meth)acrylic acid having an alkyl chain having 1 to 18 carbon atoms ester,(
2-hydroxyethyl meth)acrylate, hydroxypropyl (meth)acrylate, 2-(meth)acrylate
(N,N-dimethylaminopropyl)) Ethyl, (meth)acrylic acid ester derivatives such as N-dimethylaminopropyl (meth)acrylate; Nitrile group-containing polymerizable monomers such as (meth)acrylonitrile, etc. are mentioned,
These can be used alone or in combination of two or more.

Alkyl mercaptans having 6 to 18 carbon atoms used during polymerization include hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, tart
- Examples include dodecyl mercaptan, cetyl methicaptan, stearyl mercaptan, and one of these
Seed or 2f! or more can be used.

Polymerization is carried out using a general radical polymerization initiator at room temperature to 200 ℃
The molecular weight of the zero polymer that can be synthesized at 50 to 150 degrees Celsius is preferably 400 to 10,000.

In the present invention, the monomer (1) used as an essential component of the polymerizable monomer mixture forming the dispersion resin is a compound having a hydrolyzable silicon group directly bonded to a silicon atom, such as vinyltrimethoxysilane, Vinyltriethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, vinyltris(2-methoxyethoxy)silane, allyltriethoxysilane, trimethoxysilylpropylallylamine, etc. These 1f! Or 2f! or more can be used.

In addition, the monomer (2) used as an essential component of the polymerizable monomer mixture has a polymerizable double bond in the molecule and is capable of reacting with carboxyl groups such as epoxy groups, aziridine groups, and oxazoline groups. It is a compound having a group, for example (
Epoxy group-containing polymerizable monomers such as glycidyl acrylate and allyl glycidyl ether; Oxazoline group-containing polymerizable monomers such as 2-isopropenyl-2-oxacillin and 2-vinyloxazoline; )
Examples include aziridine group-containing polymerizable monomers such as 2-aziridinylethyl acrylate and (meth)acryloylaziridine.

The polymerizable monomer mixture has the above-mentioned 2 fffi polymerizable it
However, if necessary, it may further contain other polymerizable monomers (3), such as styrene vinyl toluene,
Styrene derivatives such as α-methylstyrene, chloromethylstyrene, styrene sulfonic acid and its salts: (meth)acrylamide, N-monomethyl (meth)acrylamide, N-monoethyl (meth)acrylamide, N,
(meth)acrylamide conductors such as N-dimethyl(meth)acrylamide; methyl (meth)acrylate;
(Meth)acrylic acid esters synthesized by esterification reaction of (meth)acrylic acid such as ethyl (meth)acrylate and butyl (meth)acrylate with 01-CI8 alcohol; 2-hydroxyethyl (meth)acrylate , 2-hydroxypropyl (meth)acrylate, hydroxyl group-containing (meth)acrylic esters such as monoesters of (meth)acrylic acid and polypropylene glycol or polyethylene glycol; ethyl (meth)acrylate 2-sulfonate; Its salts, vinyl sulfonic acid and its salts, vinyl acetate, (meth)acrylonitrile, etc., and dimethylaminoethyl (meth)acrylate,
Basic polymerizable monomers such as dimethylaminoethyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, vinylpyridine, vinylimidazole, vinylpyrrolidone; (meth)acrylic acid and ethylene glycol, 1,3-butylene glycol , diethylene glycol, 1.8-hexane glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and other polyhydric alcohol esters with two polymerizable unsaturated groups in the molecule. (meth)acrylamides such as polyfunctional (meth)acrylic acid esters, N-methylol (meth)acrylamide, and N-butoxymethyl (meth)acrylamide; and vinyl fluoride, vinylidene fluoride, vinyl chloride, and chloride. Vinylidene, divinylbenzene, diallyl phthalate, etc. can be mentioned.

Monomer (1) and monomer (
There is no particular restriction on the amount of 2) used, but in order to fully achieve the purpose of the present invention, each monomer must be used in a sufficient amount! ! It is preferably used in an amount of 0.1 to 30% by weight, more preferably 0.5 to 20% by weight in the caramel mixture.

The dispersion resin in the present invention uses a reactive surfactant made of the polymer (A) as an emulsifier, and a polymerizable monomer mixture containing monomer (1) and monomer (2) as essential components. It is obtained by emulsion polymerization in a medium by a well-known method, and any conventionally known emulsion polymerization method can be applied.For example, a polymerization catalyst, water, the above polymer (A
), a reactive surfactant and/or its salt, and a polymerizable monomer are mixed together and polymerized, or the so-called monomer dropping method, pre-emulsion method, seed polymerization method, multi-stage polymerization method, etc. The dispersion resin in the invention can be synthesized.

The polymerization temperature is 0 to 100°C, preferably 50 to 80°C.
℃, and the polymerization time is 1 to 10 hours.

During emulsion polymerization, it is possible to add a hydrophilic solvent and other known emulsifiers and additives as long as the physical properties of the polymer are not adversely affected.

The amount of the polymer (A) used as an emulsifier is not particularly limited, but it is preferably polymerizable! The amount is 0.5 to 200 parts by weight, more preferably 1 to 100 parts by weight of #mer mixture.
~15 layers total.

The purpose of adding fillers is to improve blocking and statesking resistance, but inorganic pigments have drawbacks such as high specific gravity, inconsistent shape, and poor affinity with banders. The organic pigments have the disadvantage of numerically inferior heat resistance. Therefore, in the present invention, it was decided to use amino-based hardened fine particles. Cured spherical fine particles made from amino resin do not have the above drawbacks.

The hardened spherical fine particles themselves have the general formula (wherein R1 is a hydrogen atom, an alkyl group, an aryl group, a hydroxyl group, a mercapto group, a heterocyclic group, or -N
R4R5 (R4 and R3 are each independently a hydrogen atom, a lower alkyl group, an aryl group, or a lower alkenyl group), and R2 and R5 are each independently a hydrogen atom, a lower alkyl group, an allyl group, or a lower Indicates an alkenyl group. ) Aminotriazine compound (A) represented by
It consists of an amino resin obtained by a condensation reaction between an amino group-containing compound whose main component is aldehyde, and can be obtained by a known production method. Examples of such a manufacturing method include, for example, Japanese Patent Publication No. 56-42614, Japanese Patent Application Laid-open No. 16594-1982, and Japanese Patent Application Laid-open No. 52-16594.
The method disclosed in Japanese Patent Publication No. 51493 can be mentioned, and based on the methods disclosed therein, cured spherical fine particles having excellent heat resistance and solvent resistance, having a substantially uniform particle size, and having an arbitrary particle size can be produced. is obtained.

The ayonodriazine compound (A) is a compound represented by the above formula, and includes, for example, melamine, substituted melamine, benzoguanamine, substituted benzoguanamine, acetoguanamine, substituted acetoguanamine, and the like. Among them, melamine and benzoguanamine are particularly useful because they are easily available industrially at low cost. The hardened spherical fine particles have many features not seen in conventional organic fine particles, and when combined with the above-mentioned adhesive, form a protective layer with particularly excellent sticking resistance.

The particle size of the amino-based hardened fine particles is particularly 0.5 to 5μ.
A particle size of m was advantageous in satisfying both image uniformity and staining resistance. Particle size 5μm
Although the statesking resistance was good even when it exceeded the above, the image uniformity after printing was poor.

On the other hand, when the particle size is less than 0.3 μm, the wettability of the amino-based cured fine particles to the adhesive is poor, the pigment tends to aggregate, and it takes a long time to form a coating, and favorable results are not obtained.

The blending ratio of the filler in the protective layer coating is preferably 10 to 50% by weight, more preferably 15 to 30% by weight. If the amount is less than 101i% by weight, the staking resistance will be insufficient, and if it exceeds 50% by weight, the print density will be insufficient, the barrier properties will be poor, and only unsatisfactory results will be obtained.

In addition to the amino-based hardened fine particles, it is also possible to use inorganic fillers such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, barium sulfate, clay, talc, and other inorganic fine powders.

In addition, the crosslinking agent used in the coating agent is preferably one that can react at as low a temperature as possible, such as dimethylol urea, other polymethylol ureas, dimethylol ethylene urea, dimethylol glyoxal monourein, diltyol glyoxal diurene, etc. rhein, dimethyloluron, dimethylolpropylene urea, l, 3-
Polymethylol compounds such as bis(hydroxymethyl)-tetrahydro-5-hydroxy-2-pyrimidinone, dimethyloltriazone, dimethylolmelamine, other polymethylolmelamine, polymethylolacetoguanamine, polymethylolbenzoguanamine; glyoxal, glutaraldehyde, Polyaldehyde compounds such as dialdehyde starch; nonionic water-soluble epoxy compounds such as diglycidyl ether of polyethylene glycol, glycerin diglycidyl ether, and trimethylolpropane diglycidyl ether; combinations of glycidyl esters of acrylic acid or methacrylic acid with acrylamide, etc. Water-soluble copolymers, polyamide epoxy resins, etc. can be used. Moreover, if necessary, a suitable curing accelerating catalyst may be used. The amount of crosslinking agent used is 10 oz of aqueous resin dispersion.
! The amount is preferably in the range of 1 to 30 parts by weight per part (in terms of solid content).

The coating agent used in the present invention contains the above-mentioned aqueous resin dispersion, filler, and crosslinking agent as essential components.
In addition to these components, it may be desirable to add a PH regulator, a viscosity regulator, a lubricant, an ultraviolet absorber, a mold release agent such as wax, etc. In particular, if the pH of the coating agent is inappropriate, the thermosensitive coloring layer may change color during storage and reduce the whiteness of the paper, so adjust the pH of the coating agent to prevent the thermosensitive coloring layer from developing color. The coating agent, which is preferably prepared in advance, can be obtained by uniformly dispersing and mixing the above-mentioned components using a suitable stirrer, kneader or disperser.

The synthetic paper used as a support in the present invention is made by adding fillers and additives (stabilizers, dispersants, etc.) to polyolefin resin, mixing them, melting and kneading them in an extruder, and extruding them through a die/slit at the same time. It is a single-layer structure film obtained by axial stretching or sequential biaxial stretching, or a multilayer structure film consisting of a base layer, a paper-like layer, and in some cases a surface layer.

If a support other than the above-mentioned synthetic paper, such as natural paper obtained from natural cellulose fibers, is used as a support, the resulting thermosensitive recording paper will have insufficient strength and water resistance. Examples of polyolefin resins include polyethylene, polypropylene,
The main components are ethylene-propylene copolymer and ethylene-vinyl acetate copolymer, but thermoplastic resins such as polyethylene and acrylic ester copolymer can also be mixed and used. Fillers to be added to the polyolefin resin include calcium carbonate with an average particle size of 20 am or less, calcined clay,
Examples include diatomaceous earth, talc, and silica, and for the surface layer, calcium carbonate, titanium oxide, barium sulfate, and the like. The thickness of the synthetic paper is preferably 10 to 200 μm, the basis weight is preferably 10 to 200 g/m 2 , and the synthetic paper preferably has good surface smoothness. Papers that can be used as olefin resin synthetic paper include Yopo and Polyart.
Synthetic paper commercially available under the trade name LYART is suitable.6 The heat-sensitive recording material of the present invention uses synthetic paper as a support, coats a heat-sensitive recording layer, and further coats the above-mentioned coating agent on top of the heat-sensitive recording layer. - Form an overcoat layer by drying and, if necessary, calendering.

There is no particular restriction on the thickness of the overcoat layer, but considering the effects and economy of the present invention, it is preferably 1 to 10 um.
, more preferably 2 to 5 μm.

P of the present invention! The thermosensitive coloring layer in the thermal recording material may be formed of a commonly used material. For example, a numerical leuco dye can be used as the basic colorless dye. For example, fluoran dyes give excellent results.

Examples of fluorane-based leuco dyes include 3-diethyl-6-methyl-7-anilinofluoran 3-(N-ethyl-P-)-luidino)-6-methyl-
7-anilinofluorane 3-(N-cyclohexyl-N-methylamino)-6-
Methyl-7-anilinofluorane 3-diethyl-7-(O-chloroanilino) Fluoran-3-diethyl-7-(m-trifluoromethylanilino) Fluoran-3-diethyl-7-( 0゜p-dimethylanilino)fluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran 3-dibutylamino-6-methyl-7-anilino Fluorane etc.

The acidic color developer used in the present invention has the property of liquefying and vaporizing at room temperature or higher, preferably 70°C or higher, and reacts with the above-mentioned color-forming substance to develop color, such as phthalic anhydride, gallic acid, and salicylic acid. Aromatic carboxylic acid, 1-hydroxy-2-naphthoic acid, 0-hydroxybenzoic acid, m-hydroxybenzoic acid, p-tert-butylphenol, 4-hydroxyphenoxidemethyl-4-hydroxybenzoate, 4-hydroxyacetophenone, α- Naphthol, β-naphthol, catechol, hydroquinone, 4-tert-octylcatechol, 4°4'-5
eC-butylidenephenol, 2,2-methylenebis(
4-methyl-6-tert-butylphenol), 2.
2-bis-(4-hydroxyphenyl)propane, 4.4
-isopropylidene-bis(2-tert-butylphenol), 4,4°5ec-butylidene diphenol,
Pyrogallol, phloroglycin, etc. can be used.

As the binder, for example, polyvinyl alcohol,
Starch and its derivatives, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose,
Cellulose derivatives such as methylcellulose and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone,
Acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid copolymer, styrene/maleic anhydride copolymer alkali salt,
Isobutylene/maleic anhydride copolymer alkali salts, polyacrylic acid, sodium alginate, gelatin, casein, and the like can be used.

In addition to the leuco dye, color developer, and binder, the coating solution may contain conventional additives such as sensitizers, fillers, surfactants, thermofusible substances, etc., if necessary. May be used together. In this case, fillers include, for example, inorganic fine powders such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated calcium and silica, etc. Organic fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin can be mentioned, and examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts, as well as Various waxes, mixtures of aromatic carboxylic acids and amines, benzoic acid phenyl esters, high-grade straight-linked glycols, 3,4-epoxy-hexahydrophthalic acid dialkyl high-grade ketones, and other thermoplastics with a melting point of 50 to 200°C. Mention may be made of fusible organic compounds.

[Example] Examples of the present invention are shown below, but these are given for illustrative purposes and are not intended to limit the scope of the present invention. represent

Example 104 (Preparation of Coating Liquid for Thermosensitive Coloring Layer) Solutions A and B were prepared by grinding each of the compositions having the following compositions using a sand grinder to an average particle size of 1.0 μm.

Part A 3-dibutylamino-6-methyl-7 Anilinofluorane 200 parts Polyvinyl alcohol 10% solution 200 parts Water
600 parts 4.4'-thiobis(6-tert-butyl-3-methylphenol) (Yoshitomi Pharmaceutical Co., Ltd., Yoshinox 5R) 100 parts parabenzylphenyl 100 parts (Nippon Steel Chemical Co., Ltd., P
BBP) Calcium carbonate 100 parts (Shiraishi Kogyo, Brilliant 15) Polyvinyl alcohol 10% solution 200 parts Water
SOO
Part 100 parts by weight of liquid A, 400 parts by weight of liquid B, 500 parts by weight of styrene-butadiene copolymer latex (solid content 50%), zinc stearate emulsion (solid content 20%) 3
00 parts by weight were mixed to prepare a heat-sensitive coloring liquid. This heat-sensitive coloring coating liquid was applied to high-quality paper with a basis weight of 50 g/m'' at a dry coating weight of 5.
g/ln'' and dried.

(Preparation of protective layer paint) (1) Synthesis of reactive emulsifier Charge 180 parts of isopropyl alcohol into a flask equipped with a dropping funnel, a stirrer, a nitrogen introduction tube, a thermometer, and a reflux condenser, and slowly blow in nitrogen gas until the ℃
heated to. 1.5 parts of a polymerizable monomer mixture consisting of 174 parts of acrylic acid, 36 parts of n-dodecylmercaptan, and 0.42 parts of 2.2°-azobisisobutyronitrile was added thereto.
I took my time and got it down by 7. During the dropwise addition, the temperature was maintained at 80 to 85°C, and after the dropwise addition was completed, the mixture was stirred at the same temperature for 1 hour to complete the polymerization. Furthermore, 57 parts of allyl glycidyl ether and 21 parts of triethylbenzylammonium chloride were added to the polymer thus obtained, heated to 85°C, and reacted at the same temperature for 6 hours to obtain a reactive surfactant. Ta.

(2) Polymerization of aqueous phase resin dispersion 4 parts of the above reactive surfactant solution and 1.6 parts of 28% ammonia water were charged and heated to 65° C. while slowly flowing nitrogen gas.

4 parts of a 5% aqueous solution of 2.2'-azobis(2-amidinopropane) dihydrochloride was poured into it, and then 38 parts of methyl methacrylate, 50 parts of ethyl acrylate, and methacrylate, which had been prepared in advance, were poured into the dropping funnel. glycidyl acid 1
A polymerizable monomer mixture consisting of 0 parts of vinyltrimethoxysilane and 2 parts of vinyltrimethoxysilane was added dropwise over 2 hours. After the completion of the dropwise addition, the temperature was maintained at 65°C and stirring was continued for 1 hour, followed by cooling, and the nonvolatile content was 39. .8% dispersion resin (1) was obtained.

Amino-based hardened fine particles 35 parts (Product name: Meiko Poster 512, Nippon Shokubai Kagaku Kogyo Co., Ltd.) (average particle size 1.2 μm) Dispersed resin 7 nights (1) 45 parts (methyl methacrylate/ethyl acrylate/glycidyl methacrylate/vinyl trichloride) Methoxylan copolymer) Acrylic acid-modified glyoxal 15 parts (trade name J-003. manufactured by Showa Denko@) Zn stearate 5 parts (Hydrin Z-7. manufactured by Chukyo Yushi ■) The same protective waves were formed as described above. It was coated on the heat-sensitive coloring layer to a dry weight of 3 g/l and dried to obtain heat-sensitive recording paper.

Example 2.3 Instead of the amino-based hardened fine particles used in Example 1, ``Meiko Poster S 12J'', Eposter MS (Example 2, manufactured by Nippon Shokubai Chemical Co., Ltd., average particle diameter: 2 μm), Eposter-M30 ( A thermosensitive recording paper was obtained in the same manner as in Example 1, except that Example 3 (average particle diameter: 3 μm) was used.

Heat-sensitive recording was produced in the same manner as in Example 1, except that kaolinite clay (trade name: HG Clay, manufactured by Huber, Inc., USA) was used as the protective layer component in place of the amino-based hardened fine particles in Example 1. Got paper.

Comparative Example 2 IA-embedded thermosensitive recording paper was prepared in the same manner as in Example 1, except that polyvinyl alcohol (PV A 117, manufactured by Kuraray ■) was used as a protective layer component instead of the resin dispersion in Example 1. I got it.

The same procedure as in Example 1 was used, except that polyethylene fine particles [trade name Frozen, average particle diameter 5 μm, manufactured by Seitetsu Kagaku Co., Ltd.] were used instead of the amino-based hardened fine particles in Example 1 as the components of the Yadanriyu protective layer. A thermosensitive recording paper was obtained by processing.

The heat-sensitive recording papers produced in the above Examples and Comparative Examples were calendered using a super calender to obtain a smoothness of 50,005 ec (seconds) [Oken type Beck smoothness meter] to obtain a product. Table 1 shows the results of performance tests conducted on these products. In order to evaluate the staking resistance, printing was performed under two conditions: 20°C and 0°C. Printer conditions are: 8 dots/■ convex thermal head in main scan, head voltage 16V, power supply time 20 ass
/ It was printed under the condition of sub-scanning of 3.85 IL/mm. Water resistance was evaluated by rub-off-last by dropping water droplets on the protective layer.

1st (Total 2i points) 〇 Two good Δ, Slightly poor × : Poor × We were able to provide a heat-sensitive recording material.

Claims (1)

[Scope of Claims] A synthetic paper-based thermosensitive recording paper having a heat-sensitive coloring layer consisting of a colorless or light-colored leuco dye and a color developer, and further having an overcoat layer thereon, the overcoat layer having the following properties: 1. A heat-sensitive recording material characterized in that it is obtained by applying a coating agent containing an aqueous resin dispersion, cured amino particles, and a crosslinking agent as essential components. (Note) General formula (A) ▲Mathematical formula, chemical formula, table, etc.▼(A) (In the formula, R_1 represents an alkyl group having 6 to 18 carbon atoms,
R_2, R_3, R_4, R_5 and R_6 each independently represent hydrogen, a methyl group, a carboxyl group or a carboxymethyl group, or a salt thereof, and X represents hydrogen, an ammonium base, an amine base, an alkali metal or an alkaline earth metal. , Y represents a hydrocarbon group having a polymerizable unsaturated group, Z represents a nitrile group or a phenyl group which may have a substituent, a carboxylic acid amide group or a carboxylic acid alkyl ester group, and a is 1 to 500 integer, b is 0 or an integer from 1 to 100, and c is 0 or an integer from 1 to 250. ) is used as an emulsifier, and an organic silicon monomer (1) having a hydrolyzable group directly bonded to a silicon atom and a functional group capable of reacting with a carboxyl group. A dispersion resin obtained by emulsion polymerizing a polymerizable monomer mixture containing the polymerizable monomer (2) as an essential component in an aqueous medium.