JP2001030632A - Heat sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive recording material, provided with a resistance to so-called picking, in which a part and/or the whole of an ink receptive layer provided with a printing layer applied thereon is separated upon printing or separated by a cellophane tape or the like due to the viscosity and adhesive property of the ink, maintaining a resistance to water like as a conventional material and showing an effect for preventing the feathering of the same. SOLUTION: This heat sensitive recording material is provided with a heat sensitive recording layer on one side of a substrate consisting of the principal body of wooden fiber and an ink receptive layer on the opposite side of the substrate. In such a heat sensitive recording material, the ink receptive layer is constituted at least of silica, bonding agent resin and polyamide epichlorohydrin as fillers while the same layer is provided with a resistance to picking having the adhering amount of solid constituents of 2.0-3.5 g/m2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording material, and more particularly, to a thermosensitive recording material having a back surface having a surface strength capable of coping with offset printing and capable of coping with ink jet printing. It concerns recording materials.

[0002]

2. Description of the Related Art In recent years, with the diversification of information and the expansion of needs, various recording materials have been researched, developed, and put into practical use in the information recording field.
(1) A simple image can be recorded by a heating process. (2) The mechanism of a necessary device is simple and compact, and the recording material is easy to handle and inexpensive.
And so on. In addition, various improvements have been made to the durability of printed images, such as long-term storage and use under severe storage conditions (eg, aging stability, temperature and humidity resistance, water resistance, chemical resistance, printing durability, etc.). Something that can withstand this has been put to practical use. In other words, the method of use is not limited to the mere area of information recording, and the information durability can be increased by increasing the image durability.
The recording itself is treated as a ticket or a voucher.
These are subjected to various printing processes on the front surface and the back surface for the purpose of design of the ticket itself and prevention of forgery, and high reliability is required particularly in the case of a high-value note. For example,
In the case of a lottery ticket such as a lottery ticket, variable information such as a serial number is printed in advance in a ticket processing step in order to prevent forgery and fraud.

In recent years, an ink jet system has begun to spread as a printing means for such variable information. However, in a general thermosensitive recording material having an ink receiving layer on the back surface, a resin-rich ink is used as the back surface ink receiving layer for water resistance. Because a coating layer is provided, the thermosensitive recording paper having an ink jet receiving layer on the back surface is originally a thermosensitive recording paper, so it can be used under water-containing conditions (water adhesion) or under high humidity (food packaging, etc.). In many cases, water resistance that can withstand this is required as an essential requirement. In addition, the phenomenon (feathering) of bleeding of the ink image occurs, the color changes depending on the compatibility with the resin used, and the use of the resin in a field that does not require protection of the back surface makes it particularly possible to use the back surface coating. Even in the case where the working layer is not provided, problems such as occurrence of bleeding (feathering), a low ink image density, and a flow of ink when wet with water occur.

[0004] On the other hand, since the receiving paper itself for ink jet has been developed, a receiving paper excellent in image aptitude has been developed.
An ink-jet receiving paper is described in which a coating liquid having a low solid content is applied so that the fibrous material of the substrate is at least partially exposed, and Japanese Patent Application Laid-Open No. 9-99629 discloses that An ink jet receiving paper provided with a coating layer of 6 to 10 g / m ² is described. However, these are papers for exclusive use of ink jets. Because of the high resin ratio), high-speed coating requires high-temperature drying because of the large amount of coating.However, high temperatures in the heat-sensitive recording layer coating line cause color development on the heat-sensitive surface. Simultaneous coating imposes restrictions such as drying conditions and coating speed. In addition, a thickly provided coating layer has problems such as easy powder drop, low surface strength compared to normal printing, and easy picking (peeling).

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which does not hinder handling as a heat-sensitive recording material and has a backside suitable for ink-jet printing. That is, the ink receiving layer for applying the printing layer has a picking resistance against so-called picking, in which a part and / or the whole of the receiving layer is peeled off or peeled off by a cellophane tape or the like due to the viscosity and adhesiveness of the ink during printing. In addition, an object of the present invention is to provide a heat-sensitive recording material having an effect of maintaining the water resistance at the same level as the conventional one and preventing bleeding (feathering).

[0006]

Means for Solving the Problems As a result of intensive studies, the inventor of the present invention has found that the above-mentioned object is achieved by the present invention comprising (1) a support having a heat-sensitive recording layer on one surface of a support mainly composed of wood fibers; A heat-sensitive recording material having an ink receiving layer on the opposite surface of the support,
The ink receiving layer is made of at least silica as a filler, a binder resin, and polyamide epichlorohydrin, and has a picking resistance of 2.0 to 3.5 g / m ² in terms of solid content. Characteristic thermal recording material ",
(2) The above-mentioned (1), wherein the picking resistance is 70 cm / s or more as a value with a tack 15 standard ink in a surface strength test method (JIS P8129) using an IGT printing tester. Thermal recording materials described in section
(3) The thermal recording according to (1) or (2), wherein the surface oil absorption of the ink receiving layer is 10 or more as measured by an IGT paper surface oil absorption measurement method (IGT W24). (4) “Thermal recording material according to any one of the above (1) to (3), wherein the binder resin is a carboxylic acid-modified polyvinyl alcohol”, (5) ) "Silica 1 in the ink receiving layer
(4) The thermosensitive recording material according to the above (4), wherein the total ratio of the carboxylic acid-modified polyvinyl alcohol and the polyamide epichlorohydrin of the binder resin to the binder resin is not more than 60 parts by weight. (6) that the weight ratio of the carboxylic acid-modified polyvinyl alcohol to 100 parts by weight of silica in the ink receiving layer is 10%;
20 to 30 parts by weight of polyamide epichlorohydrin
(5) The heat-sensitive recording material according to the above (5), (7) wherein the silica has a volume average particle diameter of 1.5 to 3.5 μm. The heat-sensitive recording material according to any one of the above items (1) to (6) ".

Hereinafter, the present invention will be described in detail. First, with regard to picking, conventional general ink-receiving paper cannot withstand picking for printing. The reason may not be taken into account, but if the receiving layer is 6
It has a problem that it is as thick as 〜10 μm, contains a filler (eg, silica), is insufficiently bound, and easily peels off. The present inventor has found that the problem of picking can be solved by reducing the adhesion amount (thin film thickness) in a specific range. That is, the present invention succeeded in providing a paper for heat-sensitive recording and ink jet having a picking resistance. In general, it is assumed that the thinner the film thickness, the higher the adhesiveness. Even though it is assumed that the adhesiveness is high, it is not possible to determine how much the amount of adhesion satisfies both printability and thermal paper characteristics. There was no guide.

The inventor of the present invention has proposed a method for thinning the heat-sensitive recording material of the present invention, such as a resin material capable of binding a filler (filler, typical example: silica) with a smaller amount of resin. I found Conventionally, the binder resin was 80 or more with respect to silica 100, but in the present invention, the total of the binder resin and polyamide epichlorohydrin with respect to silica 100 can be set to 60 or less. This is because the use of carboxylic acid-modified (PVA) polyvinyl alcohol and the use of polyamide epichlorohydrin have good compatibility with each other and increase the film strength. The same applies to the reason that a low resin content ratio is required for silica.

Next, regarding water resistance, polyamide epichlorohydrin has been used as a water-proofing agent in conventional heat-sensitive recording materials, but when used together with the carboxylic acid-modified polyvinyl alcohol of the present invention, it is particularly water-resistant. Was found to rise. The reason is the same as the above-mentioned increase in the strength of the color developer.

Next, with respect to feathering resistance, although not a novel means, a filler (typically silica) having a large oil absorption amount, which easily permeates the ink and promotes it, is often used. Further, although the reason cannot be explained, it is considered that the reduction in the film thickness is also involved. Further, by adding polyamide epichlorohydrin, the feathering resistance rapidly increases. Although the reason is not speculative, polyamide epichlorohydrin is cationic, and it is considered that this cationicity has an influence. At this time, a suitable ratio of the carboxylic acid-modified polyvinyl alcohol to silica is 20 to 30 parts by weight of the polyamide epichlorohydrin and 10 to 30 parts by weight of the carboxylic acid-modified polyvinyl alcohol with respect to 100 parts by weight of the silica. If the amount of the polyamide epichlorohydrin is less than 20 parts by weight, the feathering resistance and the water resistance rapidly decrease.

According to the present invention, there is provided a heat-sensitive recording material comprising a support mainly composed of wood pulp and a heat-sensitive coloring layer mainly composed of a leuco dye and a developer capable of developing the leuco dye upon heating. And silica 1 on the back surface of the heat-sensitive recording layer.
The coating layer composed of 10 to 30 parts by weight of carboxylic acid-modified polyvinyl alcohol and 20 to 30 parts by weight of polyamide epichlorohydrin is used in a solid content of 2.0 to 100 parts by weight.
The above problem can be solved by providing a thermosensitive recording material characterized by providing 3.5 g / m ² .

The silica used in the heat-sensitive recording material of the present invention preferably has a volume average particle size of 1.5 to 3.5 μm. If it is less than 1.5 μm, the image density is lowered, which is not preferable. If it is more than 3.5 μm, the surface smoothness is remarkably reduced, which is not preferable.

As the binder, carboxylic acid-modified polyvinyl alcohol is used in an amount of 10 to 30 parts by weight based on 100 parts by weight of silica.
Used by weight. If the amount is less than 10 parts by weight, the binding property is reduced and powder falling easily occurs. On the other hand, if the amount exceeds 30 parts by weight, feathering is likely to occur.

Polyamide epichlorohydrin is used as a water-proofing agent in an amount of 20 to 30 parts by weight based on 100 parts by weight of silica. If the amount is less than 20 parts by weight, the water resistance becomes insufficient, and the ink is liable to be eluted when immersed in water. On the other hand, if the amount exceeds 30 parts by weight, feathering tends to occur.

The solid content of the coating layer is 2.0 to 3.5 g.
/ M ² is preferable, and if the amount is less than 2.0 g / m ² , image bleeding is likely to occur, while 3.5 g / m ^2.
When the amount exceeds the above range, powder falling easily occurs in the case of repeated bending and the like in handling.

In the present invention, as the heat-sensitive recording layer provided on one side of the support, various conventional raw materials and layer constitutions can be used. However, when chemical resistance from the back surface is required for the purpose of use, a protective layer may be provided between the general thermal recording layer and the support and / or between the intermediate layer provided as a lower layer of the general thermal recording layer and the support. It can cope by providing. In the case where the raw material itself constituting the general thermal recording layer already has resistance to chemicals, it is possible to cope without providing the general protective layer. In the present invention, the excess amount of ink adsorbed in the backside receiving layer is released into the support to reduce the solid adhesion amount of the receiving layer to a small amount. It is not preferable to provide a protective layer on the back surface of the support for the layer. Further, an under layer may be provided between the heat-sensitive recording layer and the support.

The leuco dye used in the thermosensitive coloring layer of the present invention 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 for example, triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based dyes Are 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
-Benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3- (Np-tolyl-N-
Ethylamino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 2N- (3'-trifluoromethylphenyl)
Amino｝ -6-diethylaminofluoran, 2- ｛3
Lactam 6-bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoate, 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-pyrrolospirane, 6'-bromo-3'-methoxy-benzoindolino -Pyrrolospirane, 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-trifluoromethylanilino) 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-dipentylamino-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-
Butadien-4-yl) benzophthalide, 3- (4'-
Dimethylamino-2'-benzyloxy) -3- (1-
p-Dimethylaminophenyl-1-phenyl-1,3-
Butadien-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.

In the present invention, various electron-accepting compounds which form a color when the leuco dye is brought into contact as a color developer may be those applied to this type of heat-sensitive material. Compounds, thiophenol compounds, thiourea derivatives, organic acids and metal salts thereof, and the like can be appropriately used in combination. Specific examples thereof include the following, but are not limited thereto. Absent. 4,4'-isopropylidenebisphenol, 4,4 '
Isopropylidenebis (o-methylphenol),
4,4'-secondary butylidene bisphenol,
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), 1,1,1 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'-diphenolsulfone, 4-isopropoxy-4'-hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, p-hydroxy Isopropyl benzoate, 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, 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 ′
-Diphenol sulfone, 3,3'-diallyl-4,
4′-diphenol sulfone, α, α-bis (4-hydroxyphenyl) -α-methyltoluene, tetrabromobisphenol A, tetrabromobisphenol S,
4,4′-thiobis (2-methylphenol), 4,
4′-thiobis (2-chlorophenol), an antipyrine complex of zinc thiocyanate, 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, but are not limited to, the following. . Polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid Water-soluble polymers such as terpolymers, alkali salts of styrene / maleic anhydride copolymers, alkali salts of isobutylene / maleic anhydride copolymers, polyacrylamide, sodium alginate, gelatin, casein, polyvinyl acetate,
Latexes such as polyurethane, polyacrylic acid, polyacrylate, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene / vinyl acetate copolymer, styrene / butadiene / acrylic copolymer and the like.

In the present invention, various heat-fusible substances can be used as the sensitivity improver, and specific examples thereof include the following, but are not limited thereto. Absent. 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, m-terphenyl, triphenylmethane,
benzyl p-benzyloxybenzoate β-benzyloxynaphthalene, phenyl β-naphthoate, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, diamond carbonate, dibenzyl 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) biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyldisulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p-benzyloxybenzyl alcohol, 1,3-diphenoxy-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, bis (4-chlorobenzyl) oxalate, and the like.

In the present invention, together with the leuco dye and the developer, if necessary, auxiliary additives commonly used in this type of heat-sensitive recording material, for example, fillers, surfactants, lubricants, pressure coloring. An inhibitor and the like can be used in combination. In this case, as the filler, for example, inorganic fine powders such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium and silica In addition, organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, and vinylidene chloride-based resin can be mentioned, but may be appropriately adjusted alone and / or in combination from oil absorption. is necessary. Examples of the lubricant include higher fatty acids and metal salts thereof, higher fatty acid amides, higher fatty acid esters, various kinds of animal, vegetable, mineral or petroleum waxes.

In the heat-sensitive recording material of the present invention, a protective layer is provided on the heat-sensitive coloring layer of the present invention for the purpose of improving the head matching property at the time of printing, and improving the writing property and the printing property on the recording material. In this case, the pigment, the binder, the thermoplastic material, and the like can be used as components constituting the protective layer.

[0023]

The present invention will be described below in more detail with reference to examples. All parts and percentages shown below are based on weight. [Example 1] Preparation of heat-sensitive recording layer (Solution A): 3-dibutylamino-6-methyl-7-anilinofluoran 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts (Solution B): bis (4) -Hydroxy-3,5-dibromophenyl) sulfone 4 parts Di (p-methylbenzyl) oxalate 4 parts 4,4 '-{oxybis (ethyleneoxy-p-phenylenesulfonyl)} Polymer containing diphenol as a main component 4 parts Silica 4 parts Polyvinyl alcohol 10% aqueous solution 12 parts Water 72 parts (Liquid C): Aluminum hydroxide 30 parts Polyvinyl alcohol 10% aqueous solution 30 parts Water 40 parts Mixtures having the above composition, each having an average particle size of 1.5
μm or less using a sand mill
(Solution A), (Solution B) and (Solution C) were prepared.

(D solution): Plastic spherical hollow particle dispersion 25 parts (hollow ratio 90%, solid content concentration 40%) Styrene / butadiene copolymer latex (solid content concentration 50%) 20 parts Water 55 parts From the above composition The resulting mixture was mixed and stirred to prepare an under layer coating solution (D solution). This is commercially available high quality paper (basis weight 80
g / m ² ), and an under layer was formed by coating and drying so that the dry adhesion amount was 3.5 g / m ² .

(Solution E): (Solution A) 9.1 parts (Solution B) 90.9 parts A mixture having the above composition was mixed and stirred to prepare a thermosensitive coloring layer coating solution (Solution E). This was coated and dried on the surface of the underlayer-coated paper so that the dry adhesion amount was 5.0 g / m ² , thereby providing a thermosensitive coloring layer.

(Solution F): (Solution C) 16.7 parts Polyvinyl alcohol 10% aqueous solution 50 parts Polyamide epichlorohydrin 12.5% aqueous solution 14 parts Zinc stearate dispersion (solid content concentration 30%) 2.5 Part water 16.8 parts A mixture having the above composition was mixed and stirred to prepare a protective layer coating liquid (liquid F). This was coated and dried on the surface of the paper coated with the heat-sensitive coloring layer so that the dry adhesion amount was 2.0 g / m ² , thereby providing a protective layer.

Preparation of ink receiving layer (Solution G): Silica 15 parts Carboxylic acid-modified polyvinyl alcohol 10% aqueous solution 15 parts Water 70 parts A mixture having the above composition is dispersed using a sand mill so that the average particle size becomes 2 μm. To prepare (G solution). (Solution H): (Solution G) 53.3 parts Carboxylic acid-modified polyvinyl alcohol 10% aqueous solution 12 parts Polyamide epichlorohydrin 12.5% aqueous solution 16 parts Water 18.7 parts A mixture having the above composition was mixed and stirred. An ink receiving layer coating solution (H solution) was prepared. This was coated and dried on the back surface of the paper coated with the heat-sensitive recording layer so that the dry adhesion amount was 3.5 g / m ² , thereby providing an ink receiving layer. Further, the heat-sensitive recording surface of the present invention is subjected to a super calendering process by passing a metal roll on the heat-sensitive recording surface and a resin roll on the ink receiving layer so that the heat-sensitive recording surface has a Beck smoothness of 1500 to 2500 seconds. The material was obtained.

[Example 2] (H solution) of Example 1 was replaced with 2.0
The heat-sensitive recording material of Example 2 was obtained in the same manner as above except that the back surface receiving layer was provided by coating and drying to give a g / m ² .

Comparative Example 1 Comparative Example 1 was performed in the same manner as in Example 1 except that the ink receiving layer of (H solution) was not provided.
Was obtained. Comparative Example 2 The heat-sensitive recording material of Comparative Example 2 was prepared in the same manner as in Example 1 except that the (H solution) of Example 1 was applied and dried so as to have a weight of 6.0 g / m ² and a back surface receiving layer was provided. Obtained. Comparative Example 3 A heat-sensitive recording material of Comparative Example 3 was obtained in the same manner as in Example 1 except that 12 parts of a 10% aqueous solution of carboxylic acid-modified polyvinyl alcohol of (H solution) was changed to 24 parts. Comparative Example 4 A commercially available recording paper (EP
SON MACHJET COLOR Fine paper).

The performance of the thermosensitive recording materials obtained in the above Examples and Comparative Examples was evaluated with respect to the backside ink jet aptitude by the following method. Table 1 shows the results. <Image density> Black with EPSON MJ-500C
Blue and red are printed, and the image density is measured using a Macbeth densitometer (RD-9).
14, image black: filter visual, image blue: filter red, image red: filter green).

<Overview of Image> In the same manner, a character pattern was printed, and the image was visually evaluated for fatness and bleeding (feathering). ○: Feathering is not noticeable ×: Feathering is noticeable

<Water Resistance> Similarly, a sample on which a character pattern was printed was immersed in water at 25 ° C. for 1 minute, and the elution of the ink was visually evaluated. ：: No elution observed ×: Elution observed

<Picking Resistance> Evaluation was made with a tack 15 standard ink by a surface strength test method (JIS P 8129) using an IGT printing tester. Using an IGT printing suitability tester, the standard grade ink of tack 15 was kneaded with an ink kneading roller for 8 minutes, and the transfer roller was brought into contact with the roller where the ink became uniform for 45 seconds to perform ink deposition. After the ink deposition, printing was immediately performed at a pressure of 343 N / cm ² , and evaluation was performed.

<Oil Absorption> IGT Paper Surface Oil Absorption Measurement Method (IG
TW24). The evaluation sample was set on an IGT printability tester, and 1% Sudadanred / Dib
5.8 mg of the utilphtalate solution was collected with a microsyringe, dropped onto a transfer roller, and then pressurized at 392.
Printing was immediately performed at N / cm ² and evaluation was performed.

<Surface Interlayer Strength> Similarly, a cellophane tape was brought into contact with the surface of the sample on which the character pattern was printed, gently peeled off, and the ink was transferred to the cellophane tape side.
The surface peeling was visually evaluated. ：: No ink transfer / surface peeling observed ×: Ink transfer / surface peeling observed

[Table 1]

[0036]

As is apparent from the detailed and specific explanations above, the ink receiving layer provided with the printing layer used in the heat-sensitive recording material of the present invention has picking resistance and water resistance of the conventional ink-receiving layer. An excellent effect of maintaining the same level as that of the thermal recording paper and preventing feathering is exhibited.

Claims (7)

[Claims] 1. A heat-sensitive recording material having a heat-sensitive recording layer on one side of a support mainly composed of wood fibers and an ink-receiving layer on the opposite side of the support, wherein the ink-receiving layer has at least a filler. Consisting of silica, binder resin, and polyamide epichlorohydrin, and having a solid content of 2.0 to
A heat-sensitive recording material having a picking resistance of 3.5 g / m ² . 2. The picking resistance is 70 cm / s or more as a value with a tack 15 standard ink in a surface strength test method (JIS P8129) using an IGT printing tester. 2. The heat-sensitive recording material according to item 1. 3. The ink absorbing layer according to claim 1, wherein the surface oil absorbing property is IG.
3. The heat-sensitive recording material according to claim 1, wherein the value of T-paper surface oil absorption measurement method (IGT W24) is 10 or more. 4. The heat-sensitive recording material according to claim 1, wherein the binder resin is a carboxylic acid-modified polyvinyl alcohol. 5. The silica 10 in the ink receiving layer.
The heat-sensitive recording material according to claim 4, wherein the total ratio of the carboxylic acid-modified polyvinyl alcohol and the polyamide epichlorohydrin of the binder resin to 60 parts by weight is 60 parts by weight or less. 6. The silica 10 in the ink receiving layer.
The heat-sensitive recording material according to claim 5, wherein the weight ratio of the carboxylic acid-modified polyvinyl alcohol is 10 to 30 parts by weight and the amount of polyamide epichlorohydrin is 20 to 30 parts by weight relative to 0 parts by weight. 7. The silica has a volume average particle diameter of 1.5.
The heat-sensitive recording material according to any one of claims 1 to 6, wherein the thickness is from 3.5 to 3.5 µm.