JP2831747B2 - Thermal recording material - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a synthetic paper-based heat-sensitive recording paper, and more particularly to a heat-sensitive recording excellent in image uniformity and stick resistance, and also excellent in strength and water resistance. It is about materials.

[Prior Art] It has long been known that a color reaction occurs when a basic dye and an acidic developer are heated and melted. An example of applying this color reaction to recording paper is Japanese Patent Publication No. 43-4160. And Japanese Patent Publication No. 45-14039.

Applications of thermal recording paper include facsimile, barcode labels, measurement recorders, terminal printers such as word processors, automatic ticket vending machines, etc.In addition, instant type used as recording paper for CRT screens for ultrasonic diagnostics Is being replaced by silver halide photography.
As the use of thermal recording paper expands in this way, conventional thermal recording paper in which only a heat-sensitive paint is applied to the support, when exposed to various plasticizers, solvents, light, water, etc., prints the image area. However, there is a drawback that the color is erased and the non-image part is colored. The same tendency is observed even when the recording paper is stored for a long period of time.

As a method for improving these disadvantages, 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 on a thermosensitive coloring layer provided on ordinary paper. 56−12
No. 5354 discloses a method of applying a water-soluble polymer compound such as polyvinyl alcohol.

However, these methods only show a certain effect in preventing the decoloration of the image area or the coloring of the non-image area due to the plasticizer or oils in the wrap film, and only when a thermoplastic emulsion is used as a protective layer binder. Has the disadvantage that the sticking resistance of the thermal head is insufficient, the stick sound during printing is loud, a hot melt adheres to the head, causing printing trouble, and possibly damaging the thermal head. . Also, those coated with a water-soluble polymer substance as a protective layer are generally blended with a water-proofing agent because of the need to maintain water resistance, but since low-temperature drying is performed from the viewpoint of preventing color formation, Water resistance becomes insufficient, and when water adheres to the surface, the coating film is easily peeled off and blocking sticking occurs.

On the other hand, sticking tends to occur when printing conditions are low. The reason is considered to be that the molten material is cooled and easily adhered to the head, and development of a thermosensitive recording paper which does not cause sticking under any conditions is desired.

[Problems to be Solved by the Invention] An object of the present invention is to provide a heat-sensitive recording material in which the conventional disadvantages have been improved, that is, excellent in water resistance and sticking resistance and high in storage stability.

[Means for Solving the Problems] As a result of intensive studies, the present inventors have found that a synthetic paper-based heat-sensitive recording material using a colorless reaction of a basic colorless dye and an acidic color developer has an upper surface on a heat-sensitive coloring layer. It has been found that the above object can be achieved by providing a special protective layer.

This protective layer comprises the following aqueous resin dispersion, amino-based cured fine particles obtained by curing an amino resin obtained by a condensation reaction of an amino group-containing compound containing an aminotriazine compound as a main component with an aldehyde, and a crosslinking agent as essential components. It is obtained by applying a coating agent to be applied.

Aqueous resin dispersion: General formula (A) (Wherein, R ₁ represents an alkyl group having 6 to 18 carbon atoms, and 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,
Represents 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 A represents 1 to
B is an integer of 0 or 1 to 100, and c is an integer of 0 or 1 to 250. (A) a polymer represented by
An organic silicon monomer having a hydrolyzable group directly bonded to a silicon atom [hereinafter, a reactive surfactant comprising an emulsifier]
It is called monomer (1). ] And a polymerizable monomer having a functional group capable of reacting with a carboxyl group [hereinafter, referred to as monomer (2). ] An aqueous resin dispersion obtained by emulsion-polymerizing a polymerizable monomer mixture containing as an essential component in an aqueous medium.

[Function] General formula (4) used as an emulsifier in the present invention.
Is obtained by radical polymerization of a polymerizable monomer (a) having a carboxyl group and optionally another polymerizable monomer (b) in the presence of an alkyl mercaptan having 6 to 18 carbon atoms. Examples of the polymerizable monomer (a) include unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid, and unsaturated polycarboxylic acids such as itaconic acid, maleic acid and fumaric acid. And monoesters of these unsaturated polycarboxylic acids,
One or more of these can be used.
Other polymerizable monomers (b) include, for example, styrene derivatives such as styrene, α-methylstyrene, chlorostyrene, vinyltoluene, chloromethylstyrene, styrenesulfonic acid or a salt thereof; (eta) acrylamide, Contains amide groups such as methylolated (meth) acrylamide, alkoxymethylolated (meth) acrylamide having 1 to 4 carbon atoms, N, N-dimethylaminoethyl (meth) acrylamide, and N, N-dimethylaminopropyl (meth) acrylamide Polymerized biomonomers; (meth) acrylate having an alkyl chain having 1 to 18 carbon atoms,
2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylic acid-2
-(Meth) acrylate derivatives such as (N, N-dimethylamino) ethyl and N, N-dimethylaminopropyl (meth) acrylate; and nitrile group-containing polymerizable monomers such as (meth) acrylonitrile And these can be used alone or in combination of two or more.

Examples of the alkyl mercaptan having 6 to 18 carbon atoms used in the polymerization include n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, cetyl methcaptan, and stearyl mercaptan. Or one or more of them can be used.

Polymerization using a general radical polymerization initiator, room temperature ~ 200
C., more preferably 50-150.degree. The molecular weight of the polymer is preferably from 400 to 10,000.

In the present invention, the monomer (1) used as an essential component of the polymerizable monomer mixture forming the aqueous resin dispersion is a compound having a hydrolyzable silicon group directly bonded to a silicon atom, for example, vinyl trimethoxy. Silane, vinyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, vinyltris (2-methoxyethoxy) silane, allyltriethoxysilane, trimethoxysilylpropylallylamine And the like,
One or more of these can be used.

The monomer (2) used as an essential component of the polymerizable monomer mixture can react with a carboxyl group such as an epoxy group, an aziridine group and an oxazoline group in addition to a polymerizable double bond in the molecule. An epoxy group-containing polymerizable monomer such as glycidyl (meth) acrylate and allyl glycidyl ether; and an oxazoline group containing 2-isopropenyl-2-oxazoline and 2-vinyloxazoline. Polymerizable monomers; (meth)
Examples thereof include aziridine group-containing polymerizable monomers such as 2-aziridinylethyl acrylate and (meth) acryloylaziridine.

The polymerizable monomer mixture contains the above two types of polymerizable monomers as essential components, but may further contain another polymerizable monomer (3) if necessary. Examples of the reactive monomer (3) include styrene derivatives such as styrene vinyl toluene, α-methylstyrene, chloromethylstyrene, styrenesulfonic acid and salts thereof; (meth) acrylamide, N-monomethyl (meth) acrylamide,
(Meth) acrylamide derivatives such as N-monoethyl (meth) acrylamide and N, N-dimethyl (meth) acrylamide; (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate ) (Meth) acrylic esters synthesized by an esterification reaction of acrylic acid and a C ₁ -C ₁₈ alcohol; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acryl Hydroxyl group-containing (meth) such as monoester of acid and polypropylene glycol or polyethylene glycol
Acrylic acid esters; (meth) acrylic acid 2-ethyl sulfonate and salts thereof, vinylsulfonic acid and salts thereof,
Basic polymerization of vinyl acetate, (meth) acrylonitrile, etc., and dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, vinylpyridine, vinylimidazole, vinylpyrrolidone, etc. Monomers: (meth) acrylic acid and ethylene glycol, 1,3
-Butylene glycol, diethylene glycol, 1,6-
Polyfunctional (meta) such as hexane glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, esters with polyhydric alcohols such as pentaerythritol, dipentaerythritol, etc. having two or more polymerizable unsaturated groups in the molecule. ) Acrylates; (meth) acrylamides such as N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide; and vinyl fluoride;
Examples include vinylidene fluoride, vinyl chloride, vinylidene chloride, divinylbenzene, diallyl phthalate and the like.

The amount of the monomers (1) and (2) used in the polymerizable monomer mixture is not particularly limited, but in order to sufficiently achieve the object of the present invention, each monomer is polymerized. It is preferably used in the range of 0.1 to 30% by weight, more preferably in the range of 0.5 to 20% by weight in the monomer mixture.

The aqueous resin dispersion according to the present invention comprises the polymer (A)
A reactive surfactant consisting of an emulsifier and a monomer (1)
And a polymerizable monomer mixture containing the monomer (2) as an essential component in an aqueous medium by emulsion polymerization using a well-known method. Can be applied. For example, a polymerization catalyst, water, a reactive surfactant comprising the polymer (A) and / or a salt thereof, a method of collectively mixing and polymerizing a polymerizable monomer, or a so-called monomer dropping method, a pre-emulsion method, The aqueous resin dispersion of the present invention can be synthesized by a method such as a seed polymerization method or a multi-stage polymerization method.

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

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

The amount of the polymer (A) used for the emulsifier is not particularly limited, but is preferably 0.5 to 200 parts by weight, more preferably 1 to 15 parts by weight, per 100 parts by weight of the polymerizable monomer mixture.

The purpose of adding the filler is to improve the anti-blocking property and anti-sticking property. However, inorganic pigments have drawbacks such as large specific gravity, inconsistent shape, and poor affinity with banders. Organic pigments have the disadvantage of poor heat resistance compared to general drops. Therefore, in the present invention, amino-based cured fine particles are used as an essential component of the filler. Cured spherical fine particles made of amino resin do not have the above-mentioned disadvantages.

The cured spherical particles themselves have the general formula (Wherein, R ₁ is a hydrogen atom, an alkyl group, an aryl group,
Hydroxyl group, mercapto group, heterocyclic group or -NR ₄ R
₅ (R ₄ and R ₅ are each independently a hydrogen atom, a lower alkyl group, an aryl group or a lower alkenyl group.), And R ₂ and R ₃ are each independently a hydrogen atom, a lower alkyl group, an aryl A lower alkenyl group or a lower alkenyl group. ) Is obtained by curing an amino resin obtained by a condensation reaction between an amino group-containing compound represented by the formula (A) and an aldehyde, and can be obtained by a known production method. Examples of such a production method include JP-B-56-42614 and JP-A-52-42614.
-16594 and JP-A-52-51493 can be cited, and based on the methods disclosed therein, are excellent in heat resistance and solvent resistance, and have a substantially uniform particle diameter. Finally, cured spherical fine particles having an arbitrary particle diameter can be obtained.

The aminotriazine compound (A) is a compound represented by the above general formula, and examples thereof include melamine, substituted melamine, benzoguanamine, substituted benzoguanamine, acetoguanamine, and substituted acetoguanamine.
Among them, melamine and benzoguanamine are particularly useful because they are industrially available at low cost. The cured spherical fine particles have many features not found in conventional organic fine particles, and form a protective layer having particularly excellent sticking resistance in combination with the aqueous resin dispersion.

The particle diameter of the amino-based cured fine particles is particularly 0.5 to 5 μm.
The particle size of m was advantageous in satisfying both the image uniformity and the anti-sticking property. Particle size 5μm
The sticking resistance was good even when the ratio exceeded, but the image uniformity after printing was poor.

On the other hand, when the particle diameter is less than 0.3 μm, the amino-based cured fine particles have poor wettability to the aqueous resin dispersion liquid, tend to agglomerate the pigment, and it takes a long time to prepare a paint, and a favorable result cannot be obtained.

The compounding ratio of the filler is preferably used in the range of 10 to 50% by weight, more preferably in the range of 15 to 30% by weight in the coating material for the protective layer. If it is less than 10% by weight, the sticking resistance is insufficient. If it exceeds 50% by weight, the print density is insufficient, the barrier property is poor, and only unsatisfactory results are obtained.

As the filler, in addition to the amino-based cured fine particles, inorganic fillers such as calcium carbonate, silica, zinc oxide, titanium oxide,
It is also possible to use an inorganic fine powder such as aluminum hydroxide, barium sulfate, clay and talc together.

As the cross-linking agent used in the coating agent, those capable of reacting at as low a temperature as possible are preferable. Rain, dimethylol urone, dimethylol propylene urea, 1,3-
Bis (hydroxymethyl) -tetrahydro-5-hydroxy-2-pyrimidinone, dimethyloltriazone, dimethylolmelamine, other polymethylolmelamine, polymethylolacetoguanamine, polymethylol compounds such as polymethylolbenzoguanamine; glyoxal, glutaraldehyde, Polyaldehyde compounds such as dialdehyde starch; nonionic water-soluble epoxy compounds such as diglycidyl ether of polyethylene glycol, glycerin diglycidyl ether, trimethylolpropane diglycidyl ether; glycidyl esters of acrylic acid or methacrylic acid with acrylamide; Water-soluble copolymers, polyamide epoxy resins and the like can be used. If necessary, a suitable curing accelerating catalyst may be used. The amount of the crosslinking agent used is 100 of the aqueous resin dispersion.
It is preferable that the amount be in the range of 1 to 30 parts by weight per part by weight (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, a pH adjusting agent, a viscosity adjusting agent, a lubricant, an ultraviolet absorber In some cases, it is desirable to add a release agent such as wax. In particular, if the pH of the coating agent is inappropriate, the thermosensitive coloring layer may change its color during storage and reduce the whiteness of the paper.Therefore, adjust the pH of the coating agent so that the thermosensitive coloring layer is not colored. It is desirable to keep. The coating agent can be obtained by uniformly dispersing and mixing the above components using a suitable stirrer, kneader or disperser.

The synthetic paper used as a support in the present invention is a polyolefin resin to which fillers and additives (stabilizers, dispersants, etc.) are added and mixed, melt-kneaded with an extruder, and then mixed with a die.
A one-layer structure film obtained by simultaneous biaxial stretching or sequential biaxial stretching after extrusion from a slit, or a multilayer structure film comprising a base material layer, a paper-like layer, and a surface layer in some cases. When a support other than the synthetic paper, for example, a natural paper obtained from natural cellulose fibers, is used as the support, the resulting heat-sensitive recording paper has insufficient strength and water resistance. Polyolefin-based resins are, for example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer as a main component, other, polyethylene, thermoplastic resin such as acrylate copolymer Can also be used as a mixture. As the filler compounded in the polyolefin resin, for the base layer and the paper-like layer, calcium carbonate having an average particle diameter of 20 μm or less, calcined clay, diatomaceous earth, talc, silica, etc., and for the surface layer Examples thereof include calcium carbonate, titanium oxide, barium sulfate and the like. The synthetic paper preferably has a thickness of 10 to 200 μm and a weighing of 10 to 200 g / m ² , and preferably has good surface smoothness. As the olefin-based resin synthetic paper, synthetic paper commercially available under the trade names of Yopo and Polyart is suitable.

The heat-sensitive recording material of the present invention is formed by applying a heat-sensitive recording layer using synthetic paper as a support, further applying and drying the coating agent thereon, and, if necessary, performing a calendering process. A coat layer is formed. The thickness of the overcoat layer is not particularly limited, but is preferably in the range of 1 to 10 μm, more preferably in the range of 2 to 5 μm in consideration of the effects and economy of the present invention.

The heat-sensitive coloring layer in the heat-sensitive recording material of the present invention may be formed of a commonly used material. For example, as the basic colorless dye, a general leuco dye can be used. For example, fluoran dyes give excellent results.

Examples of the fluoran leuco dye include 3-diethylamino-6-methyl-7-anilinofluoran 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-cyclohexyl-N-methylamino) -6
-Methyl-7-anilinofluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-diethylamino-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-6-methyl-7- (0, p-Dimethylanilino) fluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran 3-dibutylamino-6-methyl-7-anilinofluoran And so on.

The acidic developer used in the present invention has a property of reacting with the chromogenic substance by liquefaction and vaporization at room temperature or higher, preferably at 70 ° C. or higher to develop the color, and such as phthalic anhydride, gallic acid, and salicylic acid. Aromatic carboxylic acid, 1-hydroxy-2-naphthoic acid, o-hydroxybenzoic acid, m-hydroxybenzoic acid, p-tert-butylphenol, 4-
Hydroxyphenoxide methyl-4-hydroxybenzoate, 4-hydroxyacetophenone, α-naphthol, β-naphthol, catechol, hydroquinone, 4-
tert-octylcatechol, 4,4'-sec-butylidenephenol, 2,2-methylenebis (4-methyl-6-tert
-Butylphenol), 2,2-bis- (4-hydroxyphenyl) propane, 4,4-isopropylidene-bis (2
-Tert-butylphenol), 4,4'-sec-butylidenediphenol, pyrogallol, phloroglysin and the like can be used.

Examples of the binder include polyvinyl alcohol, starch and derivatives thereof, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, cellulose derivatives such as ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer,
Acrylic amide / acrylic ester / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein, etc. can be used. it can.

Further, in the coating liquid, in addition to the leuco dye, the developer and the binder, if necessary, conventional additives, for example,
A sensitizer, a filler, a surfactant, a heat-fusible substance and the like may be used in combination. In this case, as the filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated inorganic fine powder such as calcium and silica,
Organic fine powders such as a urea-formalin resin, a styrene / methacrylic acid copolymer, and a polystyrene resin can be given. Examples of the heat-fusible substance include higher fatty acids and their esters, amides, and metal salts. Various waxes, mixtures of aromatic carboxylic acids and amines, phenyl benzoate, higher linear glycols, higher alkyl diketones of 3,4-epoxy-hexahydrophthalate, and other heat-fusible resins with a melting point of 50 to 200 ° C Organic compounds.

[Examples] Examples of the present invention will be shown below, but these are given for illustrative purposes and do not limit the scope of the present invention.
In the following, parts and% indicate parts by weight and% by weight, respectively.

Example 1 (Preparation of coating solution for thermosensitive coloring layer) Compositions having the following compositions were each pulverized with a sand grinder until the average particle size became 1.0 µm, to prepare solutions A and B.

Solution A 3-Dibutylamino-6-methyl-7-anilinofluoran 200 parts Polyvinyl alcohol 10% 200 parts Water 600 parts Solution B 4,4'-thiobis (6-tert-butyl-3-methylphenol) (Yoshitomi Pharmaceutical, Yoshinox SR) 100 parts Parabenzylphenyl (Nippon Steel Chemical, PBBP) 100 parts Calcium carbonate (Shiraishi Kogyo, Brilliant 15) 100 parts Polyvinyl alcohol 10% liquid 200 parts Water 500 parts A liquid 100 parts by weight, liquid B 400 By weight, 500 parts by weight of a styrene-butadiene copolymer latex (solid content 50%) and 300 parts by weight of a zinc stearate emulsion (solid content 20%) were mixed to prepare a thermosensitive coloring solution. Weigh 50 g /
dry coating amount in fine paper in m ² was coated and dried so as to 50 g / m ^2.

(Preparation of paint for protective layer) (1) Synthesis of reactive emulsifier 180 parts of isopropyl alcohol was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer and a reflux condenser, and nitrogen gas was slowly blown into the flask. Heated to 80 ° C. A polymerizable monomer mixture comprising 174 parts of acrylic acid, 36 parts of n-dodecylmercaptan, and 0.42 parts of 2,2'-azobisisobutyronitrile was added dropwise thereto over 1.5 hours. During the dropwise addition, the temperature was maintained at 80 to 85 ° C., and after the completion of the dropwise addition, the mixture was stirred at the same temperature for 1 hour to terminate the polymerization. further,
57 parts of allyl glycidyl ether and 21 parts of triethylbenzylammonium chloride 21 were added to the polymer thus obtained.
The mixture was heated to 85 ° C. and reacted at the same temperature for 6 hours to obtain a reactive surfactant.

(2) Polymerization of aqueous resin dispersion liquid Charge 4 parts of the above-mentioned reactive surfactant solution and 1.6 parts of 28% aqueous ammonia, and 65 ° C. while gently flowing nitrogen gas.
Heated.

4 parts of a 5% aqueous solution of 2,2'-azobis (2-amidinopropane) dihydrochloride was poured therein, and then 38 parts of methyl methacrylate previously prepared from a dropping funnel,
A polymerizable monomer mixture consisting of 50 parts of ethyl acrylate, 10 parts of glycidyl methacrylate and 2 parts of vinyltrimethoxysilane was added dropwise over 2 hours. Keep the temperature after dropping
Maintain stirring at 65 ° C and continue stirring for the first time.
A 9.8% aqueous resin dispersion (1) was obtained.

Amino-based cured fine particles 35 parts (trade name: Eposter S12, Nippon Shokubai Chemical Industry Co., Ltd.) (Average particle diameter 1.2 μm) Aqueous resin dispersion (1) 45 parts (methyl methacrylate / ethyl acrylate / glycidyl methacrylate / vinyl) Trimethoxylane copolymer) Acrylic acid-modified glyoxal 15 parts (trade name J-003, manufactured by Showa Denko KK) Stearic acid Zn 5 parts (Hydrin Z-7, manufactured by Chukyo Yushi Co., Ltd.) It was coated on the thermosensitive coloring layer formed as described above to a dry weight of 3 g / m ² and dried to obtain a thermosensitive recording paper.

Examples 2 and 3 Eposter MS (Example 2, manufactured by Nippon Shokubai Chemical Co., Ltd., average particle diameter: 2 μm) was used instead of the amino-based cured fine particles “Trade name Eposter S12” used in Example 1,
Except for using M30 (Example 3, same as above, average particle diameter: 3 μm), the same treatment as in Example 1 was performed to obtain a thermosensitive recording paper.

Comparative Example 1 As a protective layer component, kaolinite clay (trade name: HG clay US) was used in place of the amino-cured fine particles in Example 1.
A heat-sensitive recording paper was obtained in the same manner as in Example 1 except that Huber) was used.

Comparative Example 2 As a protective layer component, polyvinyl alcohol (PVA117K, manufactured by Kuraray Co., Ltd.) was used instead of the resin dispersion in Example 1.
Was used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

Comparative Example 3 As the protective layer component, polyethylene fine particles [trade name: Flosen,
An average particle diameter of 5 μm, manufactured by Ironmaking Chemical Co., Ltd.] was used, and a thermosensitive recording paper was obtained in the same manner as in Example 1.

The heat-sensitive recording papers produced in the above Examples and Comparative Examples were calendered with a super calender to a smoothness of 5000 sec (second) [Oken-type Beck smoothness meter] to obtain products. Table 1 shows the results of performance tests performed on these products. In order to evaluate the anti-sticking property, printing was performed at two levels of 20 ° C. and 0 ° C. Printer conditions are as follows: Head voltage 16V, energizing time 20ms / l, sub-scanning 3.85l / mm using a convex head thermal head with 8 dots / mm main scanning
Printed under the following conditions. Drop off water drops on the protective layer
The water resistance by the last was evaluated.

[Effects of the Invention] According to the present invention, a heat-sensitive recording material having good water resistance, good sticking resistance and good storage stability can be provided.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoshi Igawa 1850 Todaka, Oji, Nichinan City, Miyazaki Prefecture Inside the Oji Paper Co., Ltd. Nichinan Mill (72) Inventor Kiyoshi Kawamura 5-8 Nishioburicho, Suita-shi, Osaka (56) References JP-A-2-29383 (JP, A) JP-A 1-275183 (JP, A) (58) Fields studied (Int. Cl. ⁶ , (DB name) B41M 5/28-5/34

Claims (1)

(57) [Claims] 1. A synthetic paper base thermosensitive recording paper having a thermosensitive coloring layer comprising a colorless or pale leuco dye and a color developer, and further having an overcoat layer thereon, wherein the overcoat layer comprises A resin dispersion liquid, an amino-triazine compound and a coating agent containing an amino-based cured fine particle obtained by curing an amino resin obtained by a condensation reaction of an aldehyde with an amino group-containing compound as a main component and a cross-linking agent as an essential component. A thermosensitive recording material characterized by being obtained. (Note) General formula (A) (Wherein, R ₁ represents an alkyl group having 6 to 18 carbon atoms, and 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,
Represents 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 A represents 1 to
B is an integer of 0 or 1 to 100, and c is an integer of 0 or 1 to 250. (A) a polymer represented by
An organic silicon monomer (1) having a hydrolyzable group directly bonded to a silicon atom and a polymerizable monomer (2) having a functional group capable of reacting with a carboxyl group, using a reactive surfactant comprising An aqueous resin dispersion obtained by emulsion-polymerizing a polymerizable monomer mixture containing as an essential component in an aqueous medium.