JPH0880672A - Thermal recording material - Google Patents

Abstract

PURPOSE: To provide a thermal recording material having excellent characteristics in both of water resistance and sealing properties due to non- drying ink. CONSTITUTION: A thermal recording material is obtained by providing a thermal color forming layer containing a thermal color forming component on the surface of a support and providing an intermediate layer containing a water-soluble polymer and/or a water-dispersible polymer as a binder on the thermal color forming layer and further providing an ultraviolet curable resin layer on the intermediate layer excepting a sealing scheduled part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material for recording an image by a heat-sensitive recording method. More specifically, the surface of the heat-sensitive recording material is excellent in water resistance, and ink acceptability for imprinting with non-drying ink. The present invention relates to a heat sensitive recording material having excellent properties.

[0002]

2. Description of the Related Art A thermal recording material generally has a support and a thermosensitive coloring layer formed on the surface of the support,
It comprises a system for forming a recorded image on the heat-sensitive color-developing layer by reacting the color-developing agent in the heat-sensitive color-developing layer instantly by heating with a thermal head, a hot pen, laser light, etc. (for example, Japanese Patent Publication No. 43-4160) , Japanese Examined Patent Publication No. 45-14039, etc.).

A thermosensitive recording medium using this system has advantages that a recorded image can be obtained by a relatively simple device, maintenance is easy, and noise is not generated. It is used for recording materials in a wide range of fields such as recorders, facsimiles, computer terminals, labels, and tickets for vending machines.

In particular, recently, it has begun to be used as a recording medium for ATM of banks, meter reading of gas, electricity and water.

The heat-sensitive recording material used for these purposes is excellent in properties such as weather resistance and chemical resistance, and it is of course not fading of the image or the background covering, in particular, gas, electricity,
In the case of a recording material used for water meter reading, it may be used outdoors and in rainy weather due to a handy terminal, etc., so when the thermal recording material after recording gets wet with water, the thermal recording surface and its The back surface or the heat-sensitive recording surfaces do not adhere to each other due to blocking, the recorded image does not become unreadable due to the blocking, and even if water droplets fall on the winding side surface of the heat-sensitive recording material before recording, the heat-sensitive recording surface and its There has been a demand for water resistance such that the back surface is not blocked to cause feeding failure of the thermal recording material.

When the heat-sensitive recording body after recording is wet with water, the heat-sensitive recording surface and the back surface thereof or the heat-sensitive recording surfaces adhere to each other due to blocking, the recorded image becomes unreadable, and further, before recording. When water droplets fall on the winding side of the thermosensitive recording medium, the thermal recording surface and the back surface of the thermosensitive recording medium may block and cause a feeding failure of the thermosensitive recording medium. This is because the binder used in the layer is composed of a water-soluble polymer or a water-dispersible polymer, and this binder becomes tacky when wet.

In order to solve this problem, it is conceivable that the binder of the thermosensitive coloring layer or the protective layer is treated with a crosslinking agent to impart water resistance to the binder of these layers. There are problems peculiar to the thermosensitive recording medium, such as the fact that sufficient heat cannot be applied to the crosslinking reaction during the production of the thermosensitive recording medium, or the thermosensitive coloring layer develops color when a highly reactive crosslinking agent is used. Depending on the method, sufficient water resistance cannot be improved.

Further, the water resistance of the thermosensitive coloring layer or the protective layer can be obtained by using a binder other than the water-soluble polymer or the water-dispersible polymer, but the water-soluble polymer or the water-dispersible polymer has a high water-dispersibility. Binders replacing molecules have drawbacks in other aspects such as economy and heat resistance.

In order to solve this problem, the present inventor previously contained a thermosensitive recording material having an ultraviolet curable resin layer provided on a thermosensitive coloring layer containing a thermosensitive coloring component, or a thermosensitive coloring component. Water-soluble polymer and / on the thermosensitive coloring layer
Alternatively, a heat-sensitive recording material having an ultraviolet-curable resin layer provided via an intermediate layer using a water-dispersible polymer as a binder has been proposed (Japanese Patent Publication No. 58-35478 and Japanese Patent Application No. 5-177389).

These heat-sensitive recording materials having an ultraviolet curable resin layer as the uppermost layer have a high degree of water resistance that does not cause blocking even when used outdoors in the rain.

However, the UV-curable resin layer in this heat-sensitive recording material has no acceptability for non-drying ink such as red ink and stamp ink, and cannot be imprinted with non-drying ink such as red ink and stamp ink. .

[0012]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to have water resistance without causing problems such as blocking even when used outdoors in the rain, and to have excellent imprintability with a non-drying ink. Another object of the present invention is to provide a thermosensitive recording medium having the above properties.

[0013]

The above-mentioned problems can be solved by the present invention described below. That is, the present invention provides a thermosensitive coloring layer containing a thermosensitive coloring component on the surface of a support, and an intermediate layer containing a water-soluble polymer and / or a water-dispersible polymer as a binder on the thermosensitive coloring layer. And a UV-curable resin layer is formed on the intermediate layer except the portion to be imprinted, which is a thermosensitive recording medium.

The UV-curable resin layer is described in detail in a previously published book such as "Light / Radiation Curing Technology" published by Taiseisha Co., Ltd., or a magazine. Briefly, it is a photopolymerizable monomer. The photopolymerizable monomer and the prepolymer (oligomer) are copolymerized by irradiating the coating layer of the ultraviolet curable resin composition containing the prepolymer (oligomer) and the photopolymerization initiator as essential components with ultraviolet rays. Obtained by

The monomer and prepolymer (oligomer) in the ultraviolet curable resin composition are compatible and copolymerizable.

Examples of the prepolymer in the ultraviolet curable resin composition include unsaturated polyester, epoxy, acryl and various polyesters, and examples of the monomer include various ethylene derivatives having an ethylenically unsaturated bond.

In the heat-sensitive recording material of the present invention, the UV-curable resin layer has a pattern on the intermediate layer excluding a portion to be imprinted, for example, 0.1 to 10 g by a printing method.
(Dry) / m ² , preferably 0.5 to 6 g (dr
y) / m ² is formed.

It should be noted that, on the intermediate layer, in advance, a "meter reading slip",
A format such as “receipt” may be printed, or the ultraviolet curable resin layer may be provided and then the format may be printed on the ultraviolet curable resin layer. In the latter case, it is necessary to use an ink having high heat resistance.

The intermediate layer includes (1) a protective function for the thermosensitive coloring layer that prevents the UV curable resin from penetrating into the thermosensitive coloring layer and causing inconvenience such as background covering, and (2) vermilion and stamp ink. Fulfills the function of receiving non-drying ink such as (3) and the function of maintaining the adhesiveness with the UV-curable resin layer.

Various water-soluble polymers and / or water-dispersible polymers are used as the binder in the intermediate layer of the thermosensitive recording medium of the present invention.

Specifically, various starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, styrene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, etc. Water-soluble polymer, styrene-butadiene copolymer,
A water-dispersible polymer such as an acrylonitrile-butadiene copolymer or an acrylic ester-butadiene copolymer is used, a water-soluble polymer is particularly preferable, and PVA or modified PVA is most preferable.

As the modified PVA, carboxy modified PVA, epoxy modified PVA, acetoacetylated modified PVA, sulfonic acid modified PVA and the like are preferable.

In the heat-sensitive recording material of the present invention, by using a water-absorbing urethane polymer having a film-forming ability as a part of the binder of the intermediate layer, the intermediate layer can be made more excellent in imprintability. it can.

The water-absorbing urethane polymer having a film-forming ability, which is preferably used as a part of the binder in the intermediate layer, is formed into a film by drying, and the film has a property of repeating water absorption and moisture release. And is different in properties from the conventional water-soluble urethane polymer.

That is, in the conventional water-soluble urethane polymer, the diol component constituting the urethane polymer is a hydrophobic diol component such as a polyoxypropylene adduct or an esterification product of adipic acid and hexanediol. The water absorption rate of most commercially available urethane polymers obtained by reacting such a hydrophobic diol component with an organic isocyanate, that is, the weight before water absorption is W ₁ , and the weight after water absorption is W.
_{When set to 2} , the water absorption of the urethane polymer represented by (W ₂ / W ₁ ) × 100 is 105% or less.

In the past, research has been conducted on how to increase the water resistance (hydrolysis resistance) of urethane polymers, and there has been no concept of imparting water absorption to urethane polymers. .

On the other hand, the water-absorbing urethane polymer having a film-forming ability, which is preferably used as a part of the binder for the intermediate layer in the thermosensitive recording medium of the present invention, has a weight before absorption of W ₁ and water absorption. When the weight after the treatment is W ₂ , the water absorption rate expressed by (W ₂ / W ₁ ) × 100 is usually 120% or more, and it is formed into a film by drying, and the film absorbs water. It has the property of repeating moisture release.

If the content of the water-absorbing urethane polymer is less than 1% by weight based on the total amount of the binder in the intermediate layer, the effect of improving the imprintability of the intermediate layer due to the presence of the water-absorbing urethane polymer cannot be obtained.

When the content of the water-absorbing urethane polymer exceeds 50% by weight based on the total amount of the binder in the intermediate layer, the imprintability of the intermediate layer is improved, but the protective function of the intermediate layer is deteriorated.

The water-absorbing urethane polymer preferably used as a part of the binder in the intermediate layer has a polyoxyethylene group {-
Those containing (OCH ₂ CH ₂ ) _n } (wherein n represents an integer of 2 or more) are preferably used.

In the water-absorbing urethane polymer having the polyoxyethylene group {-(OCH ₂ CH ₂ ) _n } (wherein n represents an integer of 2 or more) which is the water-absorbing component, the polyoxyethylene group {- (OCH ₂ CH ₂ ) _n }
If (n represents an integer of 2 or more) in the formula is less than 5% by weight, the water absorbing property is lowered, and the effect of improving the ink acceptability of the intermediate layer is not sufficient.

In the water-absorbing urethane polymer containing a polyoxyethylene group {-(OCH ₂ CH ₂ ) _n } (wherein n represents an integer of 2 or more) which is a water-absorbing component, the polyoxyethylene group { _{- (OCH 2 CH 2) n} }
When (n represents an integer of 2 or more) in the formula exceeds 80% by weight, the water resistance of the intermediate layer is significantly lowered.

Therefore, the water-absorbing urethane polymer has a polyoxyethylene group {-(OCH ₂ CH ₂ ) _n } (wherein n represents an integer of 2 or more), which is a water-absorbing component, in its structural formula. It is preferable to use those containing 5 to 80% by weight.

A polyurethane polymer composition containing a polyacrylic acid-based water-absorbing polymer as a water-absorbing resin has been conventionally known, but this composition is used when preparing a coating agent for forming an intermediate layer. Since it absorbs water, it cannot be used as a component of the intermediate layer.

For the binder composed of the water-soluble polymer and / or the water-dispersible polymer forming the intermediate layer, various crosslinking agents are used in order to improve the performance such as water resistance of the intermediate layer. You can

Examples of these cross-linking agents include (1) aldehydes glyoxal, dialdehyde starch, polyacrolein (2) N-methylol compound N-methylurea, N-methylmelamine, N-methylolethyleneurea (3) activity Vinyl compound Divinyl sulfone, bis (β-hydroxyethyl sulfone) (4) Epoxy compound epiclohydrin, glycidyl methacrylate (5) Polycarboxylic acid compound Dicarboxylic acid, dicarboxylic acid chloride, methyl vinyl ether-maleic acid copolymer (6) Diisocyanate compound Toluene Diisocyanate (tolylene diisocyanate), diphenylmethane diisocyanate (7) Complexing agent Compounds such as Cu, B, Al, Ti, Zr, Sn, V and Cr can be used.

Further, the intermediate layer has a diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, and an oxidation agent in order to improve the adhesiveness with the ultraviolet-curable resin layer and further improve the imprintability. Titanium,
It is preferable to add an inorganic pigment or an organic pigment such as zinc oxide, silicon oxide, aluminum hydroxide or urea-formalin resin.

In the heat-sensitive recording material of the present invention, the color-forming system used in the heat-sensitive color-forming layer containing the heat-sensitive color-forming component provided on the surface of the support may be any one as long as it can achieve the object of the present invention. A heat-sensitive color development system by a reaction between a basic dye and an acidic substance represented by a phenolic substance is preferably used.

It is also possible to use a color forming system such as a reaction system of an imino compound and an isocyanate compound, a reaction system of a long-chain fatty acid iron salt and a polyhydric phenol, and the like.

Specific examples of the components used in the color forming system using the basic dye and the acidic substance are shown below.

The basic dyes include (1) triarylmethane compounds such as 3,3-bis (p-dimethylaminophenyl)
-6-Dimethylaminophthalide (Crystal Violet Lactone), 3- (p-Dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl)
Phthalide, 3- (p-dimethylaminophenyl) -3-
(2-Phenylindol-3-yl) phthalide, 3,
3-bis- (p-ethylcarbazol-3-yl) -3
-Dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5-dimethylaminophthalide, etc .;

(2) Diphenylmethane compound For example, 4,4-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl leuco auramine, N-2,4,5-trichlorophenyl leuco auramine and the like;

(3) Xanthene compound For example, rhodamine B-anilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-butylaminofluorane, 3-diethylamino-7- (2- Chloroanilino) fluoran, 3
-Diethylamino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-ethyl-tolylamino-6-methyl-7-anilinofluorane, 3-cyclohexyl- Methylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7- (β-ethoxyethyl) aminofluorane, 3-diethylamino-6-chloro-7-
(Γ-chloropropylaminofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N
-Cyclohexyl-N-methylamino-6-methyl-7
-Anilinofluorane, 3-diethylamino-7-phenylfluorane, 3- (N-isoamyl-N-ethylamino) -6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7 -Anilinofluorane, etc .;

(4) Thiazine compounds such as benzoyl leuco methylene blue, p-nitrobenzoyl leuco methylene blue and the like;

(5) Spiro compounds, for example, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-benzylspiro-
Dinaphthopyran, 3-methylnaphtho- (3-methoxy-
Benzo) -spiropyran and the like are used.

Further, a mixture of these is used and is appropriately selected in consideration of the desired characteristics depending on the application.

As the acidic substance, paraoxybenzoic acid benzyl ester, hydroxyphthalic acid dimethyl ester, 2,4-dihydroxybenzophenone, N-stearyl-P-aminophenol, 3,4-bisphenol A, 4-hydroxysalicylanilide, 4,4'-
Dihydroxydiphenyl ether, 4,4'-ethylidene bisphenol, 4,4'-diisopropylidene diphenol (bisphenol A), 4,4 '-(1-methylpentylidene) bisphenol, tetramethylbisphenol A, 4,4'- (Α-Methylbenzylidene) bisphenol, 4,4 ′-(p-phenylenediisopropylidene) bisphenol, 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, 4,4′-cyclohexyl Silidene bisphenol,
2,2-bis (4-hydroxy-3-isopropylphenyl) propane,

Α, α'-bis (3-methyl-4-hydroxyphenyl) -m-diisopropylbenzophenone,
n-butylbis (hydroxyphenyl) acetate,
α, α ′, α ″ -tris (4-hydroxyphenyl)-
1,3,5-triisopropylbenzene, 4,4'-
[1- [4- [1- (4-hydroxyphenyl) -1-
Methylethyl] phenyl] ethylidene] bisphenol, stearyl gallate, 2,3,4,4'-tetrahydroxybenzophenone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 2,2-bis (4,
4'-hydroxyphenyl) sulfone, 4,4'-thiobis (6-t-butyl-m-cresol), 2,2-bis (3-allyl-4-hydroxyphenyl) sulfone,
Bis (4-hydroxyphenyl) sulfide, bis (4-hydroxy-3-methylphenyl) sulfide, tetramethylbisphenol S and the like are used.

The following chemicals may be added to the thermosensitive coloring layer and / or the intermediate layer depending on the purpose.

That is, in order to further improve the imprintability of the intermediate layer, as a pigment, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, urea. -Inorganic or organic pigments such as formalin resins are used.

For the purpose of preventing head wear and sticking of the thermal recording device, higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, oxidized paraffin, polyethylene, polyethylene oxide, stearamide and caster wax. Kinds are used.

Further, as a sensitivity improver, metaterphenyl, parabenzylbisphenyl, esters of hydroxynaphthoic acid, stearic acid amide, tribenzylamine, naphthalene derivative, dibenzyl terephthalate, dibenzyl oxalate, bis (paramethylbenzyl oxalate). Various oxalate esters and the like are used.

Further, a dispersant such as sodium dioctylsulfosuccinate, a surfactant, a fluorescent dye, etc. are used as desired.

Paper is mainly used as the support in the thermosensitive recording medium of the present invention, but various non-woven fabrics, plastic films, synthetic papers, metal foils, etc., or composite sheets combining these may also be used. Good.

If desired, an undercoat layer may be provided between the support and the thermosensitive color developing layer.

Further, the intermediate layer in the thermosensitive recording medium of the present invention is generally formed as a coating layer of about 0.5 to 8 g (dry) / m ² , and the thermosensitive coloring layer is 2 to 10
It is formed as a coating layer of about g (dry) / m ² .

[0057]

EXAMPLES The specific constitution of the thermosensitive recording medium of the present invention will be explained below based on examples, but the present invention is not limited to these examples.

Production Example 1 In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube, 75 parts by weight of a polycarbonate diol having a molecular weight of about 2000, glycol ethylene oxide (EO) / propylene oxide ( PO) adduct (molecular weight: about 3000, ethylene oxide content: 4)
0% by weight) 25 parts by weight, dimethyloylpropionic acid 5.
6 parts by weight, 100 parts by weight of methyl ethyl ketone, and 0.1 parts by weight of dibutyltin dilaurate were charged, and the content was heated to 70 ° C. with stirring.

Next, hexamethylene diisocyanate was added dropwise in an amount of 2 times the molar amount of the total -OH groups of the -OH group of the polycarbonate diol and the -OH group of the glycol ethylene oxide / propylene oxide adduct.

After the dropwise addition of hexamethylene diisocyanate, the temperature was further raised to 85 ° C. and the reaction was continued until the residual amount of isocyanate reached the theoretical amount.

The reaction was terminated when the residual amount of isocyanate reached the theoretical amount, the heating was stopped, and the reaction mixture was cooled to 40 ° C.

Subsequently, 2.5 parts by weight of ethylenediamine was added dropwise to react.

By measuring the amount of isocyanate, the end point of the reaction was confirmed by the disappearance of the isocyanate.

After the reaction was completed, 2.8 parts by weight of ammonia water and 500 parts by weight of ion-exchanged water were added, and the mixture was further added to 6 parts.
By removing methyl ethyl ketone by topping at 0 ° C., a 20 wt% emulsion aqueous solution (a) of a water-absorbing urethane polymer having film forming ability was obtained.

Production Example 2 The procedure of Production Example 1 was repeated except that polyadipate diol having a molecular weight of about 2000 (butanediol content: 10% by weight) was used in place of the polycarbonate diol in the process of Production Example 1. A 20% by weight aqueous emulsion solution (b) of a water-absorbing urethane polymer having film forming ability was obtained.

Production Example 3 In the process of Production Example 1, a molecular weight of about 3 was used in place of the glycol ethylene oxide / propylene oxide adduct.
A 20 wt% emulsion aqueous solution (c) of a water-absorbing urethane polymer having film forming ability was obtained by the same operation as in Production Example 1 except that 000 polyethylene glycol was used.

Example 1 (1) Formation of thermosensitive coloring layer Preparation of solution A 3-di-butylamino-6-methyl-7-anilinofluorane ... 10 parts by weight 5% aqueous methylcellulose solution ... 5 Parts by weight Water ... 25 parts by weight

This composition was ground with a sand mill until the average particle size became 0.8 μm. Preparation of solution B 4,4'-diisopropylidenediphenol: 10 parts by weight 5% by weight methylcellulose aqueous solution: 5 parts by weight Water: 25 parts by weight

This composition was ground with a sand mill until the average particle size became 1.5 μm. Liquid C adjustment Metaterphenyl: 10 parts by weight 5% by weight methylcellulose aqueous solution: 5 parts by weight Water: 25 parts by weight

This composition was ground with a sand mill until the average particle size became 1.0 μm.

Then, 40 parts by weight of the above-mentioned solution A and solution B 80
Parts by weight, solution C 40 parts by weight, 45% by weight acrylic emulsion (Bonron S-1120 manufactured by Mitsui Toatsu Chemicals, Inc.)
40 parts by weight and 40 parts by weight of water were mixed and stirred to obtain a coating liquid for the thermosensitive color developing layer.

50 g of the obtained coating liquid for the thermosensitive coloring layer
/ M ^{2 on} a support made of high-quality paper, 4 g (dry)
/ M ² and dried to form a thermosensitive coloring layer.

(2) Formation of Intermediate Layer 20% by weight solution of polyvinyl alcohol (Kuraray Poval 105, manufactured by Kuraray Co., Ltd.) ... 400 parts by weight 20% by weight aqueous emulsion of water-absorbing urethane polymer having film forming ability (A) ... 100 parts by weight Silica (P-527, manufactured by Mizusawa Chemical Co., Ltd.) ... 10 parts by weight Glyoxal ... 10 parts by weight Water ... 150 parts by weight

This composition was mixed and stirred to obtain a coating liquid for the intermediate layer.

The obtained coating liquid for the intermediate layer was coated on the above thermosensitive color developing layer in an amount of 3 g (dry) / m ² , dried and then subjected to gloss calendering.

(3) Formation of UV-Curable Resin Layer An UV-curable resin composition (Dicure ROP varnish, Dainippon Dainippon) was formed on the above-mentioned intermediate layer by an offset printing tester in a pattern shape excluding a portion to be imprinted. Ink chemical industry
Co., Ltd.) was applied at a rate of about 1 g / m ² and then cured by an ultraviolet irradiation device to obtain a thermosensitive recording medium as an example product of the present invention.

Example 2 Instead of the 20% by weight aqueous emulsion (a) of the water-absorbing urethane polymer in the coating liquid for the intermediate layer of Example 1,
A heat-sensitive recording material, which is an example product of the present invention, was obtained in the same manner as in Example 1 except that a 20% by weight aqueous emulsion (b) of a water-absorbing urethane polymer was used.

Example 3 Instead of the 20 wt% emulsion aqueous solution (a) of the water-absorbing urethane polymer in the coating liquid for the intermediate layer of Example 1,
A heat-sensitive recording material, which is an example product of the present invention, was obtained in the same manner as in Example 1 except that the 20% by weight aqueous emulsion (c) of the water-absorbing urethane polymer was used.

Example 4 The procedure of Example 1 was repeated except that the coating liquid for the intermediate layer was prepared by removing the 20% by weight emulsion aqueous solution (a) of the water-absorbing urethane polymer to form the intermediate layer. Example 1
By the same operation as above, a thermosensitive recording medium, which is an example product of the present invention, was obtained.

Comparative Example 1 A thermosensitive recording medium for comparison was obtained by the same operation as in Example 1 except that the formation of the ultraviolet curable resin layer was omitted.

Comparative Example 2 In the formation of the ultraviolet-curable resin layer of Example 1, the same procedure as in Example 1 was performed except that the ultraviolet-curable resin was formed on the entire surface of the intermediate layer. I got a record.

Experiment Each of the thermosensitive recording media of the above-mentioned Examples and Comparative Examples was finished in a winding of 69 mm width, and thermosensitively recorded using a Canon Handy Terminal Printer HT9000 (trade name),
The following various tests were conducted. The results are shown in Table 1.

Measurement of Recording Density The optical density of the recorded image is measured by an optical densitometer Macbeth RD918.
Was measured using.

Marking test Shachihata X stamper ink (Shachihata Industry Co., Ltd.)
Imprint) and malt vermilion (manufactured by Shachihata Kogyo Co., Ltd.) were used for marking. Immediately after the marking and 10 minutes after the marking, the marking portion was rubbed with a fingertip to visually judge the degree of the marking property.

In Table 1, ⊚: the marking characters have no bleeding and are clearly visible. ◯: The marking characters have some bleeding but are visible. Δ: Rubbing is slightly difficult to see, but practical Not bad, x: not visible due to rubbing.

Blocking Test 1 After dripping water droplets on the recording surface of the heat-sensitive recording material after heat-sensitive recording,
The recording surface of another thermosensitive recording medium of the same type was superposed on this recording surface, and a load of 100 g / m ² was applied from above to 20 ° C.
It was left to stand in a room of 65% RH for 24 hours. Next, the degree of blocking when the thermosensitive recording materials were peeled off with fingertips was evaluated.

In Table 1, ∘: no blocking, x: blocking occurred, so that a part of the thermosensitive color developing layer was broken and it was difficult to read the thermosensitive recording.

Blocking Test 2 After dripping water droplets on the recording surface of the thermosensitive recording medium after thermosensitive recording,
This recording surface is overlaid with the back surface of another thermosensitive recording medium of the same type, and a load of 100 g / m ² is applied from above, at 20 ° C., 6
It was left to stand in a 5% RH room for 24 hours. Next, the degree of blocking when the thermosensitive recording materials were peeled off with fingertips was evaluated.

In Table 1, ∘: no blocking, x: blocking occurred, part of the thermosensitive color developing layer was broken, and it was difficult to read the thermosensitive recording.

Blocking Test 3 A water drop was hung on the end surface of the winding of each thermosensitive recording medium, and 20
After leaving it in a room at 65 ° C and RH of 65% for 24 hours, the thermal recording material is used for Canon Handy Terminal Printer HT.
The runnability of the thermosensitive recording medium when thermosensitively recorded at 9000 was tested.

In Table 1, ∘: the thermal recording material has no blocking and the running property of the thermal recording material is good, and x: the thermal recording material is not conveyed due to blocking, and is described.

[0092]

[Table 1]

[0093]

As is clear from the results of Table 1, the heat-sensitive recording material of the present invention has excellent properties in both water resistance and imprintability with a non-drying ink.

Claims (3)

[Claims] 1. A thermosensitive coloring layer containing a thermosensitive coloring component is provided on the surface of a support, and an intermediate layer containing a water-soluble polymer and / or a water-dispersible polymer as a binder is provided on the thermosensitive coloring layer. A heat-sensitive recording material, characterized in that an ultraviolet-curable resin layer is provided on the intermediate layer except for a portion to be marked. 2. The heat-sensitive recording material according to claim 1, wherein 1 to 50% by weight of the binder in the intermediate layer is composed of a water-absorbing urethane polymer having a film-forming ability. 3. A water-absorbing urethane polymer having film-forming ability has a structural formula represented by a polyoxyethylene group {-(OCH ₂ CH ₂ ) _n } (where n is 2
The thermal recording material according to claim 2, containing 5 to 80% by weight of the above integers.