JPH05112071A - Manufacturing method for thermal recording material, and thermal recording material manufactured by the same method - Google Patents

Abstract

PURPOSE:To produce a thermal recording material excellent in chemical resistance and water resistance with extremely good productivity by high speed coating while sufficiently holding the function of a protective layer and that of the thermal recording material itself. CONSTITUTION:In the production of a thermal recording material wherein a thermal color forming layer and a protective layer are successively laminated to a support, different resins are used in the formation of the thermal color forming layer and the protective layer and the crosslinking agent of the resin for forming the protective layer is compounded with the resin for forming the thermal color forming layer or the crosslinking agent of the resin for forming the thermal color forming layer is compounded with the resin for forming the protective layer and the thermal color forming layer and the protective layer are successively laminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermosensitive recording medium having excellent chemical resistance and water resistance, and a thermosensitive recording material obtained by the production method.

[0002]

2. Description of the Related Art A heat-sensitive recording material provided with a color-developing agent and a thermosensitive color-developing layer containing an acidic substance as a main component for coloring the color-developing agent when heated is
Since it is relatively inexpensive, and the recording machine is compact and easy to maintain, it is used in a wide range of fields as a recording medium such as a facsimile and a printer. In addition, recently, along with the diversification of information media, the use of tickets for automatic vending machines such as commuter passes, bar code paper in POS systems, display labels for products, and other uses have expanded. In these new applications, the conventional usage form and usage environment are different, and for example, formation of a pressure-sensitive adhesive layer on the back surface, and bonding processing with other support such as PET,
Also, wallets containing a plasticizer such as dibutyl phthalate, regular insertion, contact with a plastic eraser, and sticking to food wraps having oil, water, alcohol, vinegar, etc. adhered thereto are performed.

However, these plasticizers, oils, and alcohols lead to decolorization of the color-developed portion and undeveloped color. for that reason,
In order to impart chemical resistance and water resistance, an overcoat layer is formed on the thermosensitive coloring layer and a backcoat layer on the back surface, which is mainly composed of a water-soluble resin or a water-insoluble resin. As such a known technique, a method of providing a protective layer of a heat-sensitive recording material by a roll blade coating method (JP-A-1-11328)
No. 0 Mitsubishi Paper Mills Co., Ltd., a protective layer containing casein and methylolurea as main components to improve storage stability (Japanese Patent Publication No. 3-4034 Oji Paper Co., Ltd.), carboxyl group-modified polyvinyl alcohol and polyamide Those provided with a protective layer containing an epoxy resin as a main component (JP-A-59-59)
No. 162088, Tamagawa Paper Manufacturing Co., Ltd., and a protective layer is provided with a cross-linking agent that reacts with a resin for forming an adjacent protective layer in at least one of the protective layers (JP-A-59-67082). Tamagawa Paper Co., Ltd. and the like are known.

Further, as a material for the protective layer, which has a particularly small coating amount and is effective as a protective layer, a water-soluble resin such as polyvinyl alcohol or casein and a cross-linking agent for making the water-soluble resin water resistant are the main components. Although the protective layer to be effective is, in terms of the characteristics of the thermal recording paper as a protective layer coating liquid in production,
Since it cannot be heat-treated, it must be a combination of room temperature cross-linking. Therefore, if the solid content of the liquid is increased as in high-speed coating such as blade coating, there are problems such as shortening of liquid pot life and gelation. In addition, in order to impart water resistance not only to the protective layer but also to the coating layer including the heat-sensitive layer, it is naturally necessary to make the heat-sensitive layer water resistant, but the coating texture due to the agglomeration of the color former components by the addition of a crosslinking agent. There are problems such as roughness, print density, and decrease in color development sensitivity.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a heat-sensitive recording material excellent in chemical resistance and water resistance, which allows the protective layer and further the function of the heat-sensitive recording material itself to be sufficiently exerted and the production efficiency is not lowered. And a heat-sensitive recording material obtained by the method.

[0006]

According to the present invention, in a method for producing a thermosensitive recording material in which a thermosensitive coloring layer and a protective layer are sequentially laminated on a support, a thermosensitive coloring layer forming resin and a protective layer forming resin are provided. A method for producing a heat-sensitive recording material, characterized in that different resins are used for Further, in a method for producing a thermosensitive recording material in which a thermosensitive coloring layer and a protective layer are sequentially laminated on a support, a thermosensitive coloring layer forming resin and a different resin for the protective layer forming resin are used, A cross-linking agent for the protective layer forming resin in the thermosensitive color forming layer forming resin,
A method for producing a heat-sensitive recording material is provided in which a cross-linking agent for the thermosensitive coloring layer-forming resin is added to the protective layer-forming resin, and the thermosensitive coloring layer and the protective layer are sequentially laminated. A heat-sensitive recording material obtained by the manufacturing method is provided.

That is, in view of the present situation, the inventors of the present invention have conducted earnest studies on a manufacturing method for providing a thermosensitive coloring layer and a protective layer having excellent chemical resistance and water resistance on a support, and as a result, the thermosensitive coloring layer and the protective layer were protected. Resins that are water resistant with different cross-linking agents are used for each layer, and by using these cross-linking agents for different layers, there are no problems due to the addition of cross-linking agents, and thermal recording materials with excellent chemical resistance and water resistance can be obtained. I found that it can be manufactured.

As described above, the method for producing a thermosensitive recording material of the present invention comprises a thermosensitive coloring layer containing a specific resin and a crosslinking agent on a support,
Although it is provided by laminating a protective layer, since each coating solution does not cause a problem due to the addition of a cross-linking agent, as a coating method, a high-concentration, high-viscosity method can be selected from general air knife, wire bar, and other coating methods. The blade coating method, which allows high-speed coating of liquids, can be widely used without any restrictions on the coating method.
Further, even in the case of the combination of the resin and the crosslinking agent, since the crosslinking reaction proceeds immediately after the compounding and the pot life of the coating liquid is extremely short, it is possible to use the combination which has not been used. It was also confirmed that it can be used widely.

[0009] The coating amount of the protective layer formed on the heat-sensitive color developing layer is 1.0~10g / m ² preferably 2-5 g / m ² and is chemical resistance coating amount is less than 1.0 g / m ² When it exceeds 10 g / m ² , there are problems such as a decrease in print density and color development sensitivity, which is not suitable.

Further, in order to improve the head matching property and the coating property, it is preferable to add an organic or inorganic pigment, but the addition to the protective layer is 15 to 200% by weight based on the protective layer resin.
It is preferably 30 to 150% by weight, and if it is less than 15% by weight, absorption to the heat-sensitive color developing layer becomes large, a layer with a low adhesion amount and a uniform barrier property cannot be formed, and drying is difficult. If the amount exceeds the above range, a uniform layer can be formed, but the barrier property is insufficient, which is not preferable. When the blade coating method is used as a high-speed coating method, the liquid concentration is controlled so that the viscosity of the B-type viscometer is 200 to
It may be adjusted to 5000 cps, preferably 500 to 2000 cps.

Mainly pigments and resins are used in the protective layer coating liquid which is adjusted as described above.
Clay, calcined clay, calcium carbonate, magnesium carbonate, magnesium oxide, titanium oxide, zinc oxide, aluminum hydroxide, silica, aluminum silicate, magnesium silicate, barium sulfate, talc, polystyrene resin, urea formalin resin, starch and the like. However,
It is not particularly limited.

As the resin, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, gelatin, gum arabic, casein,
Water-soluble polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide, polyamide-polyacrylamide copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, diisobutylene-maleic anhydride copolymer, etc. Resin, styrene-butadiene-based copolymer, styrene-acrylic acid-based copolymer, acrylonitrile-butadiene-based copolymer,
Examples thereof include various synthetic resin emulsions such as acrylic acid copolymers, but are not limited thereto. If desired, various water-soluble resin waterproofing agents can be used.

In order to form the heat-sensitive color forming layer on the surface of the support of the present invention, a conventional leuco dye, a color developer, a binder and, if necessary, various conventional compounding agents such as a sensitivity improving agent are used. It can be formed by blending a filler, a filler, and the like, and binding and supporting on a support.

As the leuco dye used in the present invention, a leuco dye generally known in this type of leuco recording material is applied. Leuco compounds of dyes such as are preferably used. Specific examples of such leuco dyes include:
For example, the following may be mentioned. 3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6
-Dimethylaminophthalide (also known as crystal bioleptlactone), 3,3-bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide , 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3- (N-methyl-N-isoamyl Amino) -6-
Methyl-7-anilinofluorane, 3- (N-methyl-
N-isobutylamino) -6-methyl-7-anilinofluorane, 3- (N-methyl-N-amylamino) -6
-Methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane, 3- (N-methyl-N-iso-propylamino) -6 -Methyl-7-anilinofluorane,
3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino- 7,
8-benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3- (Np-tolyl-N
-Ethylamino) -6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- {N- (3'-trifluoromethylphenyl) amino} -6 -Diethylaminofluorane, 2-
{3,6-bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoate lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino-7- ( o-
Chloranilino) fluorane, 3-dibutylamino-7
-(O-Chloranilino) fluorane, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino-6
-Methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-
(N, N-diethylamino) -5-methyl-7- (N,
N-dibenzylamino) fluorane, benzoylleuco methylene bull-, 6'-chloro-8'-methoxy-benzoindolino-pyrrolispirane, 6'-bromo-3'-methoxy-benzoindolino-pyrrolispirane, 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-diethylamino-6-methyl-7-
(2 ', 4'-Dimethylanilino) fluorane, 3-
(2'-methoxy-4'-dimethylaminophenyl) -3
-(2'-hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3-morpholino-7- (N-propyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-trifluoromethylanilinoflu Oran,
3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7 −
(Α-phenylethylamino) fluorane, 3- (N-
Ethyl-p-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-
Methoxycarbonylphenylethyl) fluorane, 3-
Diethylamino-5-methyl-7- (α-phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3- (N-methyltoluidino) -7- (pn-butylanilino) ) Fluoran, 3- (N-benzyl-N-cyclohexylamino)
-5,6-benzo-7-α-naphthylamino-4'-bromofluorane, 3,6-bis (dimethylamino) fluorenspyrro (9,3 ')-6'-dimethylaminophthalide, 3- ( N-ethyl-N-cyclohexylamino)
-5,6-benzo-7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-chloro-7
-Anilinofluorane, 3- (N-ethyl-N-2-ethoxypropylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-tetrafurfurylamino) -6- Methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino-4 ', 5
′ -Benzofluorane, 3-diethylamino-6-methyl-7- (2 ′, 4′-dimethylanilino) fluorane and the like. 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-tetrachlorophthali 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.

In the present invention, various electron-accepting compounds such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof can be applied as a color developer in the present invention. Examples include, but are not limited to, those shown below. Bentonite, zeolite, acid clay, activated clay, silica gel, phenol resin, 4,4'-isopropylidene bisphenol, 3,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis (o-methylphenol), 4, 4'-Secondary butylidene bisphenol 4,4'-isopropylidene bis (o-tert-butylphenol), zinc p-nitrobenzoate, 1,3,5
-Tris 4-tert-butyl-3-hydroxy-2,
6-dimethylbenzyl isocyanuric acid, 2,2- (3,
4'-dihydroxyphenyl) propane, bis (4-hydroxy-3-methylphenyl) sulfide, 4- (β
-(P-methoxyphenoxy) ethoxy) salicylic acid,
1,7-bis (4-hydroxyphenylthio) 3,5-
Dioxaheptane, 4,4'-cyclohexylidene diphenol, 4,4'-isopropylidene bis (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-methyl) phenol, 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-methyl) phenol, 4,4'-diphenol sulfone, 4,2'-diphenol sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone, 4-benzyloxy-4 '-
Hydroxydiphenyl sulfone, 4,4′-diphenol sulfoxide, isopropyl P-hydroxybenzoate,
Benzyl P-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,
2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N'-diphenylthiourea, N, N'- Di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, salicyl-o-chloroanilide, 2-hydroxy-
3-naphthoic acid, antipyrine complex of zinc thiocyanate, zinc salt of 1-acetyloxy-2-naphthoic acid, 2
-Acetyloxy-3-naphthoic acid zinc salt, 2-acetyloxy-1-naphthoic acid zinc salt, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid,
Metal salts of zinc, aluminum, calcium, etc. of hydroxynaphthoic acid bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4-hydroxyphenyl) acetic acid benzyl ester, 4- {β- (p-methoxyphenoxy) ethoxy} Salicylic acid, 1,3-bis (4-hydroxyphenyl) benzene, 1,4-bis (4-hydroxyfel)
Benzene, 3,4-dihydroxy-4'-methyldiphenyl sulfone, 2,4'-diphenol sulfone, 2,
2'-diallyl-4,4'-diphenol sulfone, 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 obtain the heat-sensitive recording material of the present invention, a leuco dye, a color developer and the above-mentioned auxiliary components may be bound and supported on a support. As the binder in this case, various conventional binders can be appropriately used. Specific examples of such a binder include the followings. Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, sodium polyacrylate,
Polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide In addition to water-soluble polymers such as sodium alginate, gelatin and casein, polyvinyl acetate, polyurethane, polyacrylic acid ester, polymethacrylic acid ester, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer, etc. Latexes such as emulsions, styrene / butadiene copolymers, styrene / butadiene / acrylic copolymers.

In the case of obtaining the heat-sensitive recording material according to the present invention, various heat-fusible substances can be used as the sensitivity improver, and specific examples thereof include the following compounds, but they are not limited thereto. It is not something that will be done. Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β -Naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid methyl ester, diphenyl carbonate, glare coal carbonate, terephthalic acid dibenzyl ester, terephthalic acid dimethyl ester, 1,
4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-
Bis (phenoxy) ethane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-bis (phenoxy) butane,
1,4-bis (phenoxy) -2-butene, 1,2-bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1,4-bis (phenylthio) butane, 1,4
-Bis (phenylthio) -2-butene, 1,2-bis (4-methoxyphenylthio) ethane, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) Benzene, p- (2-vinyloxyethoxy) biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, 1,3-dibenzoyloxypropane, dibenzyl disulfide, 1,1-diphenylethanol , 1,1-diphenylpropanol, p- (benzyloxy) benzyl alcohol, 1,3-diphenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, bis (4-methyl oxalate) Benzyl), dibenzyl oxalate Ester, oxalic acid bis (4-chlorobenzyl) 1,5-bis (p- methoxyphenyl) -3-oxa-pentane, 1,2-bis (4-methoxyphenoxy) propane.

Further, in the present invention, if necessary, an auxiliary additive component commonly used in this kind of heat-sensitive recording material, for example,
A filler, a surfactant and the like can be used in combination. In this case, as the filler, for example, calcium carbonate, magnesium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, inorganic carbonate such as surface-treated calcium carbonate or silica In addition to fine powder, organic fine powder such as urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin and vinylidene chloride resin can be used. As other additive substances, lubricants such as zinc stearate and calcium stearate, various surfactants, and defoaming agents are added as necessary.

In the present invention, as the cross-linking agent for the thermosensitive color forming layer forming resin or the cross-linking agent for the protective layer forming resin, known ones such as glyoxal, epichlorohydrin derivative, dimethylol urea, melamine / formalin resin can be used. According to the thermosensitive color forming layer forming resin or the protective layer forming resin used, a crosslinking agent suitable for each is selected and used.

Here, the amount of the cross-linking agent used for the resin used in the thermosensitive coloring layer and the protective layer is 5 to 5 for each resin.
If it is 0 parts by weight, preferably 10 to 30 parts by weight and less than 5 parts by weight, the water resistance is insufficient, and even if it exceeds 50 parts by weight, the water resistance is nevertheless conversely the color density, the sensitivity decrease and the chemical resistance. It is not preferable because of deterioration of the properties. Also, of course, various pH
It is possible to use a regulator, a catalyst and the like, and since the resin and the cross-linking agent are separate layers, they may be used on either side and are not particularly limited.

Regarding the layer structure, an undercoat layer and a back layer may be provided if necessary. Moreover, you may surface-treat with a super calendar etc. as needed.

[0022]

EXAMPLES Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the invention. The parts and% shown below are based on weight.

Comparative Example 1 Liquid A Preparation 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-phenylaminofluorane 5 parts 1,4-bis (2-vinyloxyethoxy) benzene 10 parts calcium carbonate 15 parts Polyvinyl alcohol 10% aqueous solution (PVA 117 Kuraray Co., Ltd.) 15 parts Water 55 parts The above composition was ground with a sand mill to an average particle size of 3 μm. Preparation of liquid B 4-isopropoxy-4'-hydroxydiphenyl sulfone 25 parts 1,1,3-tris (3-tert-butyl-4-hydroxy-6-methylphenyl) butane 5 parts polyvinyl alcohol 10% aqueous solution (PVA 117 (Kuraray Co., Ltd.) 15 parts Water 55 parts The above composition was ground by a sand mill to an average particle size of 3 μm. Then 100 parts of liquid A, to adjust the heat-sensitive coating solution B was then mixed and stirred to 100 parts, the coating amount after drying is 6 g / m ² on a commercial fine paper surface of the basis weight of 58 g / m ² Thus, the thermosensitive coloring layer was formed by coating and drying by the blade coating method. Liquid C adjustment Baking clay 1 part Itaconic acid-modified polyvinyl alcohol 10% aqueous solution of alkali salt 20 parts (KL 318) Water 7 parts were mixed and stirred, and the viscosity measured by a B-type viscometer was 1000 cps (2
0 ° C), and a protective layer is formed on the thermosensitive coloring layer so that the weight after drying is 5 g / m ² by a blade coating method at a coater speed of 350 m / min. Comparative example 1 was dried by coating under the condition of 6.0%.
A heat-sensitive recording material of was obtained.

[0023]

Example 1 A 30% aqueous solution of polyamide epichlorohydrin resin (Kamen K-1300) was added to the heat-sensitive coating solution of Comparative Example 1.
Dick Hercules Co., Ltd. is used as a protective layer resin 30
The heat-sensitive color forming layer and the protective layer were coated and dried in the same manner as in Comparative Example 1 except that the content was adjusted so that the content was adjusted to 0.1% to obtain a heat-sensitive recording material of Example 1.

[0024]

EXAMPLE 2 Use C of Comparative Example 1 on the thermosensitive color developing layer of Example 1.
Glyoxal 40% aqueous solution is added to the solution of the thermosensitive coloring layer resin 2
A protective layer was applied and dried in the same manner as in Comparative Example 1 except that the content was adjusted to 0% to obtain a heat-sensitive recording material of Example 2.

[0025]

Comparative Example 2 The same procedure as in Comparative Example 1 was conducted except that the polyamide epichlorohydrin resin added to the heat-sensitive coating solution in Example 1 and the glyoxal added to the protective layer coating solution in Example 2 were added to the protective layer and the thermosensitive color developing layer, respectively. The color-developing layer and the protective layer were applied and dried to obtain a heat-sensitive recording material of Comparative Example 2.

[0026]

Examples 3, 4, 5 and Comparative Examples 3, 4 Examples 1, 1 except that the resins and crosslinking agents used in Examples 1, 2 and Comparative Example 2 were changed to the resins and crosslinking agents shown in Table 1. 2 and Comparative Example 2
A liquid was prepared and coated and dried in the same manner as in Examples 3, 4, and 5,
Thermal recording materials of Comparative Examples 2 and 3 were obtained. However, Comparative Example 2,
In No. 3, when the coating speed was 350 m / min, formation of a poor heat-sensitive color forming layer and / or wavy formation of the protective layer occurred, and a uniform protective layer could not be formed. Therefore, the coating was dried at 150 m / min. Further, Comparative Example 4 could not be coated due to aggregation of the thermosensitive color developing layer coating liquid and remarkable thickening of the protective layer coating liquid.

Each of the heat-sensitive recording materials obtained above was calendered so that the Bekk smoothness was 1500 to 2000 seconds. After leaving the above-prepared thermal recording materials of Examples 1 to 5 and Comparative Examples 1 to 4 in an environment of 20 ° C. and 60% RH for 7 days, the thermal recording material was a commercial bar code printer (TEC B-
30) was used to print solid black and a bar code under the condition of a printing speed of 4 inch / sec, and the following test was conducted. The results are shown in Table 1.

(1) Plasticizer resistance test In a 40 ° C. atmosphere, a vinyl chloride food wrap film was applied to a recorded portion and an unrecorded portion at a pressure of 200 g / cm ² for 24 hours.
After contacting for a period of time, the change in density of the recording area was measured. (2) Oil resistance test In a 40 ° C atmosphere, cottonseed oil was applied and allowed to stand for 24 hours, and the change in the density of the recorded area was measured. (3) Water resistance test The test piece was completely submerged in water at 20 ° C. and left for 1 hour,
After confirming the elution state of the coated surface, it was taken out and the surface was rubbed with a finger to examine the peeled state of the coated surface, and the judgment was made as follows. ◯: No elution of the coated surface and no peeling due to friction. B: Little elution on the coated surface, but easily peeled off by friction. X: The coated surface is eluted. (4) Head matching property Printing was continuously carried out for 5 km, and the printed image and the state of residue on the head were observed. ◯: There is almost no residue on the head, and no abnormalities are found in the printed image. Δ: Adhesion of dust on the head is seen, but abnormalities in the printed image are not noticed. X: Abnormality is found in the printed image due to the residue on the head.

[0029]

[Table 1]

[0030]

INDUSTRIAL APPLICABILITY According to the present invention, the function of the protective layer and the function of the heat-sensitive recording material itself are fully exhibited, and since it is suitable for high-speed coating, the heat-sensitive recording material can be manufactured with extremely high production efficiency. Have an effect. The heat-sensitive recording material thus obtained has excellent chemical resistance and water resistance.

Claims (3)

[Claims] 1. A method for producing a thermosensitive recording material in which a thermosensitive coloring layer and a protective layer are sequentially laminated on a support, wherein different resins are used for the thermosensitive coloring layer forming resin and the protective layer forming resin, and the thermosensitive coloring layer forming resin is used. A method for producing a heat-sensitive recording material, which comprises blending a cross-linking agent for a resin for forming a protective layer into a resin for forming a color-forming layer, and successively laminating a thermosensitive color-forming layer and a protective layer. 2. A method for producing a thermosensitive recording material in which a thermosensitive coloring layer and a protective layer are sequentially laminated on a support, wherein different resins are used for the thermosensitive coloring layer forming resin and the protective layer forming resin, and the thermosensitive coloring layer forming resin is used. A thermosensitive color forming layer and a protective layer are sequentially laminated by blending a cross-linking agent for the protective layer forming resin in the color forming layer forming resin and a cross-linking agent for the thermosensitive color forming layer forming resin in the protective layer forming resin, respectively. A method for producing a heat-sensitive recording material, comprising: 3. A heat-sensitive recording material obtained by the manufacturing method according to claim 1.