JP3173748B2 - Thermal recording material - Google Patents

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, and more particularly to an improvement in a heat-sensitive recording material having a heat-sensitive layer on a support.

[0002]

2. Description of the Related Art Conventionally, various thermosensitive recording materials having a thermosensitive coloring layer comprising a leuco dye and a color developing agent as main components on a support have been known. It is widely used in the fields of computer output, printers such as calculators, recorders for medical measurements, facsimile machines, vending machines, thermal labels, and thermal copying.

On the other hand, in recent years, there has been a strong demand for high-sensitivity thermosensitive recording materials in response to a reduction in power supply accompanying a reduction in size of a recording apparatus and a decrease in printing energy accompanying an increase in recording speed.

In order to increase the sensitivity of the heat-sensitive recording material, various methods have been proposed in which an intermediate layer is used between the support and the heat-sensitive coloring layer in order to improve the heat insulating property and the uniformity of the coloring. For example, a method in which a heat-expandable hollow plastic pigment or non-expandable glass or fine hollow particles having a shell of aluminosilicate or the like as a shell is contained in an intermediate layer (Japanese Unexamined Patent Publication No.
No. 5093, JP-A-60-248390, etc.) and a method of providing a two-layered intermediate layer in which a pigment layer is provided on a layer containing non-expandable fine hollow particles having a shell of a thermoplastic resin (JP-A No. 62-5886).

[0005] However, in the above-mentioned method of containing foamable plastic pigment or non-foamable inorganic fine hollow particles in the intermediate layer, it is difficult to form a uniform intermediate layer, and the surface tends to be non-uniform. There is a disadvantage that the formed image lacks uniformity. In the method of providing the two-layer intermediate layer, the heat insulating effect of the fine hollow particle layer is impaired by providing the pigment layer, and the fine hollow particles are low in specific gravity and as a noble pigment in lightweight coated paper. Since many of them are used and the hollow ratio is low, they do not have a sufficient heat insulating effect, and as a result, a high-sensitivity thermosensitive recording material has not been obtained.

A method of incorporating a non-foamable plastic hollow filler having a high hollow ratio into an intermediate layer (Japanese Patent Laid-Open No. 1-11 / 1990)
No. 3282, JP-A-2-164580, JP-A-3-1
No. 47888, etc.) are also known. These non-foamable hollow fillers have the advantage that the intermediate layer is easily and uniformly formed as compared with the foamable hollow filler, and the heat insulating effect of the intermediate layer can be improved. Various materials are used as the resin forming these hollow fillers, but styrene resin, styrene-acrylic resin, and acrylic resin are preferably used from the viewpoint of heat resistance and the like.

Incidentally, these fillers usually have no binding properties themselves, so that a binder must be used. In the known method, a water-soluble resin or an emulsion resin is used as the binder. However, water-soluble resins do not have water resistance, and when a cross-linking agent is added to make up for it, there is a drawback in that the hollow filler agglomerates, and even if it does not agglomerate, it does not exhibit the water resistance effect. Difficult to do. Therefore, an emulsion resin having excellent water resistance and not causing aggregation of the coating liquid for forming an intermediate layer is often used. However, the emulsion-based resin has a weaker binding force than the water-soluble resin, and has a weaker penetration of the liquid for forming a thermosensitive coloring layer. Therefore, the thermosensitive recording material using the same has a weaker tape adhesion resistance (cellophane tape). And the layer is easily peeled off).

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which overcomes the above-mentioned drawbacks and has high sensitivity, excellent tape adhesion resistance and excellent water resistance.

[0009]

According to the present invention, there is provided a heat-sensitive recording material having a heat-sensitive coloring layer which can be colored by heat on a support, wherein a non-foaming material is provided between the support and the heat-sensitive coloring layer. A heat-sensitive recording material comprising a hollow filler, a polyvinyl alcohol-based resin as a binder, and an intermediate layer mainly containing an aziridine-based cross-linking agent as a cross-linking agent is provided. The thermal recording material is provided, wherein the volume hollow ratio of the filler is 45% or more.

That is, the present invention relates to a heat-sensitive recording material having an intermediate layer provided between a support and a heat-sensitive layer, wherein the intermediate layer comprises a non-foamable hollow filler having a hollow ratio of 45% or more as a filler and a polyvinyl alcohol-based filler as a binder. Resin (PVA-based resin), which uses an aziridine-based crosslinking agent as a crosslinking agent as a main component. The use of the aziridine-based crosslinking agent does not cause aggregation of the non-foamable filler, and also allows the PVA-based resin to have water resistance. Further, by using a PVA-based resin, penetration of the liquid for forming a thermosensitive coloring layer into the intermediate layer is promoted, and as a result, the adhesiveness of the thermosensitive recording material to tape can be improved.
Therefore, these non-foamable fillers, PVA-based resin,
By using an aziridine-based crosslinking agent in the intermediate layer, a heat-sensitive recording material having high sensitivity, excellent tape adhesion resistance, and excellent water resistance can be obtained.

The non-foamable hollow filler used in the present invention is composed of a synthetic resin, and various substances can be used as the synthetic resin. The synthetic resin is not limited, but in consideration of heat resistance, a styrene resin is used. , A styrene-acrylic resin and an acrylic resin are preferred. The volume hollow ratio of the non-foamable hollow filler is preferably 45% or more. When it is 45% or more, the heat insulating effect of the under layer is increased, and the sensitivity is improved. Further, the average particle diameter is preferably from 0.4 to 1.5 μm.

The polyvinyl alcohol resin used as a binder in the present invention includes epoxy-modified PVA, silanol-modified PVA, acetoacetyl-modified PVA, acrylamide-modified PVA, butyralized PVA-maleic acid copolymer, N- Methylol urethane-modified PVA, amino-modified PVA, and fully saponified PV
A, various saponified PVA, carboxyl-modified PVA, silicon-containing PVA, etc., but are not limited thereto, and in particular, completely saponified PVA, partially saponified PVA, carboxyl group-modified PVA, silicon-containing PVA
A shows good results. Also, two or more types can be combined.

Specific examples of the aziridine-based crosslinking agent used as a crosslinking agent in the present invention are shown in Table 1 below, but are not limited thereto.

[Table 1- (1)]

[Table 1- (2)]

The intermediate layer of the present invention may contain an auxiliary additive such as an interfacial lubricant, if necessary, for improving the wettability, or may be used in combination with other various fillers.

In the present invention, as a method of coloring by heat, a method utilizing a color-forming reaction between a leuco dye and a developer, a method utilizing a reaction between a diazo compound and a coupler,
There is a method utilizing the reaction between an isocyanate and an amine, and the like, but the coloring method is not particularly limited. Here, a method using a general leuco dye will be described.

In the present invention, the leuco dye used in the thermosensitive coloring layer is used alone or in combination of two or more.
As such leuco dyes, those applied to this type of heat-sensitive material are arbitrarily applied, and examples thereof include triphenylmethane, fluoran, phenothiazine, auramine, spiropyran, and indolinophthalide. A leuco compound of a dye is preferably used. Specific examples of such leuco dyes include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl)-
Phthalide, 3,3-bis (p-dimethylaminophenyl) -6
-Dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (p-dimethylaminophenyl)
-6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-
Dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,
7-dimethylfluoran, 3-N-methyl-N-isobutyl-6-
Methyl-7-anilinofluoran, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7,8-benzfluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3- (N-p-tolyl-N-ethylamino) -6-
Methyl-7-anilinofluoran, 3-pyrrolidino-6-
Methyl-7-anilinofluoran, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluoran, 2- {3,6-bis (diethylamino) -9- (o-
(Chloranilino) xanthyl lactam lactam｝, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-dibutylamino-7- (o -Chloroanilino) fluoran, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N
-Cyclohexylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino ) Fluoran, 3- (N, N-diethylamino) -5
-Methyl-7- (N, N-dibenzylamino) fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-
3'-methoxy-benzoindolino-spiropyran, 3-
(2′-hydroxy-4′-dimethylaminophenyl) -3-
(2′-methoxy-5′-chlorophenyl) phthalide, 3- (2 ′
-Hydroxy-4'-dimethylaminophenyl) -3- (2 '
-Methoxy-5'-nitrophenyl) phthalide, 3- (2'-
(Hydroxy-4'-diethylaminophenyl) -3- (2'-
Methoxy-5'-methylphenyl) phthalide, 3- (2'-methoxy-4'-dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3
-Morpholino-7- (N-propyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethyl (Anilino) fluoran, 3-pyrrolidino-7- (di-p-chlorophenyl)
Methylaminofluoran, 3-diethylamino-5-chloro-
7- (α-phenylethylamino) fluoran, 3- (N-ethyl
-p-Toluidino) -7- (α-phenylethylamino) fluoran, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluoran, 3-diethylamino-5-methyl-7-
(α-phenylethylamino) fluoran, 3-diethylamino-7-piperidinofluoran, 2-chloro-3- (N-methyltoluidino) -7- (pn-butylanilino) fluoran, 3-
(N-methyl-N-isopropylamino) -6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3,6-bis (dimethylamino) fluorenespiro ( 9,3 ′)-6′-dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino) -5,6-benzo-7-α
-Naphthylamino-4'-bromofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-N-ethyl-N
-(2-ethoxypropyl) amino-6-methyl-7-anilinofluoran, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluoran, 3-diethylamino
-6-methyl-7-mesitidino-4 ', 5'-benzofluoran, 3-
(p-dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} phthalide, 3- (p-dimethylaminophenyl) -3- {1,1-bis ( p-dimethylaminophenyl) ethylene-2-yl} -6-dimethylaminophthalide,
3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-phenylethylene-2-yl) phthalide, 3- (p-
Dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl) -6-dimethylaminophthalide, 3- (4'-dimethylamino-2'-methoxy)-
3- (1 ''-p-dimethylaminophenyl-1 ''-p-chlorophenyl-1 '', 3 ''-butadiene-4 ''-yl) benzophthalide, 3-
(4'-Dimethylamino-2'-benzyloxy) -3- (1 ''-p-dimethylaminophenyl-1 ''-phenyl-1 '', 3 ''-butadiene-4 ''-yl) benzophthalide , 3-dimethylamino-6-dimethylamino-fluorene-9-spiro 3 ′ (6′-dimethylamino) phthalide, 3,3-bis {2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ) Ethenyl} -4,5,6,7-tetrachlorophthalide, 3-bis {1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl} -5,6-dichloro-4,7- Dibromophthalide, bis (p-dimethylaminostyryl) -1-naphthalenesulfonylmethane, bis (p-dimethylaminostyryl) -1
-p-tolylsulfonylmethane and the like.

Examples of the color developing agent used in the thermosensitive coloring layer of the present invention include various electron-accepting compounds capable of coloring the leuco dye upon contact, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, and organic compounds. Acids and metal salts thereof are preferably applied, and specific examples thereof include the following.

4,4'-isopropylidenebisphenol,
4,4′-isopropylidenebis (o-methylphenol),
4,4′-secondary butylidenebisphenol 4,4′-isopropylidenebis (2-tert-butylphenol), 4,4′-cyclohexylidenediphenol,
4,4′-isopropylidenebis (2-chlorophenol),
2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis
(6-tert-butyl-2-methylphenol), 1,1,3
-Tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis ( 6-tert-butyl-2-methylphenol),
4,4′-diphenolsulfone, 4-isopropoxy-4′-hydroxydiphenylsulfone, 4-benzyloxy-4′-hydroxydiphenylsulfone, 4,4′-diphenolsulfoxide, isopropyl P-hydroxybenzoate, P -Benzyl hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,
5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane, 1,3-bis (4-hydroxyphenylthio) -propane, 1,3-bis (4-hydroxyphenylthio ) -2-Hydroxypropane, N, N′-diphenylthiourea, N, N′-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, 2-hydroxy-3-naphthoic acid, 2 -Hydroxy-1
-Naphthoic acid, 1-hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum and calcium, bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4-hydroxyphenyl) acetic acid benzyl ester , 1,3-bis (4-hydroxycumyl) benzene, 1,4
-Bis (4-hydroxycumyl) benzene, 2,4'-diphenolsulfone, 3,3'-diallyl-4,4'-diphenolsulfone, α, α-bis (4-hydroxyphenyl) -α- Methyltoluene, antipyrine complex of zinc thiocyanate,
Tetrabromobisphenol A, tetrabromobisphenol S, 4,4'-thiobis (2-methylphenol), 4,4'-
Thiobis (2-chlorophenol) and the like.

In order to produce the heat-sensitive recording material of the present invention,
When the leuco dye and the developer are bound and supported on the support, various conventional binders can be appropriately used, and specific examples thereof include the following.

Polyvinyl alcohol, starch and derivatives thereof, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, cellulose derivatives such as methyl cellulose, ethyl cellulose, etc .; -Da, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene /
Maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein and other water-soluble polymers, polyvinyl acetate, polyurethane, polyacrylic acid, Polyacrylate, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene /
Emulsions such as vinyl acetate copolymers and latexes such as styrene / butadiene copolymers and styrene / butadiene / acrylic copolymers.

In the present invention, various heat-fusible substances can be used as a sensitivity improver, and specific examples thereof include the following, but are not limited thereto. . Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate and zinc behenate, p-benzyl Biphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, phenyl β-naphthoate, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl Carbonate, gliacol carbonate, dibensil terephthalate, dimethyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-diphenoxyethane, 1,2 -
Bis (3-methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-diphenoxy-2-butene, 1,2-
Bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1,4-diphenylthiobutane, 1,4-diphenylthio
2-butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2
-Vinyloxyethoxy) bifer, p-aryloxyphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyldisulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p -Benzyloxybenzyl alcohol, 1,3-phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-
Octadecylcarbamoylbenzene, 1,2-bis (4-methoxyphenoxy) propane, 1,5-bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, bis (4-methylbenzyl) oxalate, oxalic acid Bis (4-chlorobenzyl) and the like.

When a heat-sensitive recording material is obtained according to the present invention, if necessary, together with a leuco dye, a developer and the compound of the present invention, additional components commonly used in this type of heat-sensitive recording material, such as fillers and surfactants Agents and the like can be used in combination. In this case, as a filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide,
Inorganic fine powders such as barium sulfate, clay, kaolin, talc, surface-treated calcium and silica, and urea
Examples include organic fine powders such as formalin resin, styrene-methacrylic acid copolymer, polystyrene resin, and vinylidene chloride resin.

Further, in the heat-sensitive material of the present invention, a resin-containing protective layer can be provided on the heat-sensitive coloring layer for the purpose of head matching and image stability. Examples of the binder used for the protective layer include polyvinyl alcohol, cellulose derivatives, starch and derivatives thereof, carboxyl group-modified polyvinyl alcohol, polyacrylic acid and derivatives thereof, styrene / acrylic acid copolymer and derivatives thereof, and poly (meth). Aqueous solutions of acrylamide and their derivatives, styrene / acrylic acid / acrylamide copolymer, amino group-modified polyvinyl alcohol, epoxy-modified polyvinyl alcohol, polyethyleneimine, aqueous polyester, aqueous polyurethane, isobutylene / maleic anhydride copolymer and derivatives thereof Resin, polyester, polyurethane, acrylate (co) polymer, styrene /
Acrylic copolymer, epoxy resin, polyvinyl acetate,
Examples include, but are not limited to, polyvinylidene chloride, polyvinyl chloride, and derivatives thereof.
In addition, a waterproofing agent, a thermosetting organic filler, an inorganic filler, a wax, a thermoplastic material, and the like can be used for the protective layer as needed. Further, a back coat layer can be provided on the back surface of the support, if necessary.

[0025]

Next, the present invention will be described in more detail by way of examples. All parts and percentages are based on weight. (Formation of Intermediate Layer) Examples 1 to 5 (using components shown in Table 2) (Solution A) Non-foamable hollow filler dispersion (30%) 30.0 parts PVA resin aqueous solution (10%) 50.0 Part Aziridine crosslinking agent (100%) 1.0 part Water 19.0 parts (B liquid) Non-foamable hollow filler dispersion (30%) 30.0 parts PVA resin aqueous solution (10%) 50.0 parts Azirine type Crosslinking agent (100%) 1.0 part Water 19.0 parts

Comparative Examples 1 to 5 (using the components shown in Table 3) (Liquid C) Non-foamable hollow filler dispersion (30%) 30.0 parts PVA resin aqueous solution (10%) 50.0 parts Water 20 0.0 part (D liquid) Non-foamable hollow filler dispersion (30%) 30.0 parts Emulsion-based fat dispersion (48%) 10.0 parts Water 60.0 parts (E liquid) Non-foamable hollow filler Dispersion (30%) 30.0 parts PVA resin aqueous solution (10%) 50.0 parts Crosslinking agent of Comparative Examples 4 and 5 (25%) (Table 2) 0.8 parts Water 49.2 parts

[0027]

[Table 2]

[0028]

[Table 3]

Each of the above intermediate layer forming liquids was weighed to 45 g / m ^2.
And dried on a high-quality paper having a dry weight of 7 g / m ² to obtain an intermediate layer.

(Formation of Thermal Sensitive Coloring Layer) (Solution F) 3- (N-methyl-N-cyclohexyl) amino- 10.0 parts 6-methyl-7-anilinofluoran 10% aqueous solution of polyvinyl alcohol 10.0 parts Water 80.0 parts (Solution G) 4-hydroxyphenyl-4'-isopropoxy 10.0 parts Phenyl sulfone Calcium carbonate 10.0 parts 1,1,3-tris (2-methyl-4-hydroxy-5.0 Part 5-cyclohexylphenyl) gatane 10% aqueous solution of polyvinyl alcohol 20.0 parts Water 55.0 parts After dispersing both the F and G liquids in a sand mill for 24 hours, mix each liquid at F: G = 1: 3. obtain a heat-sensitive coloring layer forming coating solution, the drying to an intermediate layer coating material paper weight 5 g / m ²
To obtain thermosensitive coloring layer papers of Examples and Comparative Examples.

(Formation of Protective Layer) (H Solution) Kaolin 10.0 parts Polyvinyl alcohol 10% aqueous solution 10.0 parts Water 80.0 parts These were dispersed in a sand mill for 15 hours to obtain a kaolin dispersion liquid. (Solution J) Kaolin dispersion (Solution H) 20.0 parts Polyvinyl alcohol 10% aqueous solution 40.0 parts Epichlorohydrin crosslinking agent (25%) 3.2 parts Zinc stearate aqueous dispersion (30%) 0.5 Parts 36.3 parts of water (liquid J) was applied onto the paper of the thermosensitive coloring layer with a dry weight of 5 kg /
coating and drying so as to be m ^2, and more subjected to a surface treatment by a super calender, Examples 1-5 to prepare a heat-sensitive recording material of Comparative Example 1-5.

The following tests were conducted for each heat-sensitive recording material, and the results are shown in Table 4.・ Sensitivity test A thermal printer with a thin film head manufactured by Matsushita Electronic Components Co., Ltd. under the conditions of a head power of 0.68 w / dot, a line recording time of 10 msec / line, and a scanning line density of 8 × 7.7 dots / mm. , Pulse widths of 0.6, 0.8 and 1.
0 msec and print density is measured by Macbeth densitometer R
It is measured with a model D-914 (filter w106). -Tape adhesion test (1) Adhere Nichiban cellophane tape (4 mm width) to the sample. (2) Using a peeling tester, the adhered cellophane tape is peeled at 20 m / min, and the strength required for peeling at that time is measured. -Water resistance test The sample was immersed in 150 ml of room temperature water in a 200 ml beaker for 8 hours, taken out of the water, and rubbed three times with a finger to check the peeling condition. …: Does not peel. X: Peeled off.・ Liquidity After leaving the coating solution at room temperature for 8 hours, the particle size is measured with a coulter counter. ×: increase of average particle diameter by 20% or more (agglomeration is severe) ○: increase of average particle diameter within 20% (minus aggregation)

[0033]

[Table 4]

[0034]

As is clear from Table 4, the heat-sensitive recording material of the present invention has a non-foamable hollow filler between the support and the heat-sensitive coloring layer, a polyvinyl alcohol-based resin as a resin, and an aziridine-based cross-linking agent as a cross-linking agent. By providing an intermediate layer containing as a main component, high sensitivity, excellent tape adhesion resistance, and excellent water resistance are obtained. When the hollow filler having a volume hollow ratio of 45% or more is used, the sensitivity is further improved.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-241987 (JP, A) JP-A-3-33296 (JP, A) JP-A-2-190388 (JP, A) JP-A-2- 57382 (JP, A) JP-A-1-113282 (JP, A) JP-A-63-264394 (JP, A) Patent 3121399 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) B41M 5/28-5/34

Claims (2)

(57) [Claims] 1. A heat-sensitive recording material having a heat-sensitive coloring layer capable of being colored by heat on a support, wherein a non-foamable hollow filler and a polyvinyl alcohol-based resin as a binder are provided between the support and the heat-sensitive coloring layer. And a heat-sensitive recording material comprising an intermediate layer mainly containing an aziridine-based crosslinking agent as a crosslinking agent. 2. The heat-sensitive recording material according to claim 1, wherein the non-foamable hollow filler has a volume hollow ratio of 45% or more.