JP2002019296A - Heat sensitive recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive recording paper, neither lowering of an image quality such as the omission of dots or the like on the surface of a heat sensitive recording layer at a threaded part of which nor waving at the reel up of which develops and on which an easily manufacturable antifalsification measure is applied. SOLUTION: In the heat sensitive recording paper, which has a heat sensitive recording layer including an electron donable compound, an electron acceptable compound and an adhesive on a paper support, yarn-like or band-like threads are put in the paper support by a paper making fashion under the stage that the thickness of the paper support is set to be three times as much or more as the diameter of the yarn-like thread or the thickness of the band-like thread.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording paper utilizing a color-forming reaction between an electron donating compound and an electron accepting compound, and more particularly to a thermosensitive recording paper provided with anti-counterfeiting properties. Things.

[0002]

2. Description of the Related Art A thermosensitive recording medium is known which utilizes a color development reaction between an electron-donating compound and an electron-accepting compound and reacts both compounds with heat energy from a thermal head to obtain a recording portion. I have. Such a thermosensitive recording medium is
Since it is relatively inexpensive, the recording device is compact and its maintenance is easy, it is used not only as a recording medium for facsimile and various computing devices but also in a wide range of fields.

Recently, with the rapid improvement in print preservability, thermosensitive recording media have been used in fields where only thermal transfer recording media can be used, and variable information can be transferred at high speed. Although it is used for betting tickets, lottery tickets, commuter passes, tickets, and the like because of its recordable advantages, it is necessary to prevent falsification and counterfeiting in order to use a heat-sensitive recording medium especially for cashable betting tickets and lotteries.

As a method for preventing forgery of a heat-sensitive recording medium, for example, a method of forming a watermark pattern on a paper support is disclosed in Japanese Patent Application Laid-Open No.
165463, and JP-A-10-3156.
No. 20 discloses a method using a paper support in which a tape-like thread having a heat-sensitive recording layer on a film is formed.

[0005] However, in these conventional techniques, dots are missing in a recorded image, particularly a recorded image where a thread is formed, and the recorded image quality tends to be low. Inferior in operability at the time of manufacture, the surface of the portion where the thread is formed in the manufactured thermal recording medium is slightly raised to impair the smoothness (hereinafter referred to as "bumpiness"). There is a problem that the roll obtained is corrugated when wound up.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a thermal recording medium using a thread-supported paper support, in which dots are missing on the surface of the thermal recording layer at a thread portion (at and near the location where the thread is applied). It is possible to provide a thermosensitive recording paper having a countermeasure for preventing forgery, which can be easily manufactured without deterioration in recording image quality, generation of wrinkles during manufacturing, unevenness of the surface of the thermosensitive recording medium, and corrugation during winding. is there.

[0007]

According to the present invention, there is provided a thermosensitive recording medium comprising:
A heat-sensitive recording paper having a heat-sensitive recording layer containing an electron-donating compound, an electron-accepting compound, and an adhesive on a paper support, wherein a thread-like or belt-like thread is formed on the paper support,
The thickness of the paper support is at least three times the diameter of the thread-like thread or the thickness of the belt-like thread.

[0008]

FIG. 1 is a sectional view of a thermosensitive recording medium according to one embodiment of the present invention. In the embodiment shown in FIG. 1, a heat-sensitive recording layer 2 is provided on one surface of a paper support 1, and a thread 3 is provided inside the paper support 1.
(In FIG. 1, a belt-shaped thread) is formed. One or two or more threads can be formed in the paper support. It is also possible to use a band-like thread and a thread-like thread together.

Paper support The present invention relates to a heat-sensitive recording paper having a heat-sensitive recording layer containing an electron-donating compound, an electron-accepting compound and an adhesive on a paper support. One means is to use a paper support into which a thread-like or band-like thread is milled and whose thickness is at least three times the diameter of the thread-like thread or the thickness of the band-like thread.

When the thickness of the paper support is less than three times the diameter of the thread-like thread or the thickness of the belt-like thread, the paper support may be uneven or a super calender for improving the recording image quality after the formation of the heat-sensitive recording layer. There is a possibility that wrinkles are likely to be generated during the smoothing process by the method described above. The thickness of the paper support is preferably about 4 to 10 times, particularly about 4 to 8 times.

FIG. 2 shows a thermosensitive recording medium used in the present invention.
FIG. 3 is a cross-sectional view of the paper support into which the thread is formed, showing a position at which the thread is formed in the paper support. The thread making position will be described below with reference to FIG. 2 showing an example in which the belt-like thread 3 is used, but the same applies to the case where a thread-like thread is used. As shown in FIG. 2, since the thread 3 is formed on the paper support 1, the front surface a and the back surface b of the paper support 1 on the heat-sensitive recording layer side are formed.
And exist substantially in parallel.

Assuming that the thickness of the paper support 1 is T and the thickness of the thread 3 is t, T is at least three times t, preferably 4 to
10 times. Further, the position where the thread 3 is made is not particularly limited, but it is preferable that the thread 3 is made so as not to be exposed from the surface of the paper support 1.

Generally, the distance D ₁ from the front surface (surface on the heat-sensitive recording layer side) a of the paper support 1 to the front surface (surface on the heat-sensitive recording layer) c of the thread 3 is determined by the thickness of the thread. 1 of t
It is preferably about 7 to 7 times, particularly about 1.5 to 5 times, and the thread 3 is moved from the back surface b of the paper support 1 (the surface opposite to the front surface a on the heat-sensitive recording layer side). Distance D to back surface d (surface opposite to front surface c on thermal recording layer side)
₂ is about 0.5 to 6 times the thickness t of the thread, and especially about 0.2.
It is preferably about 5 to 4 times. In the present invention, D ₁ and D ₂ are selected from the above range, and the total thickness of D ₁ + D ₂ + t is three times or more, preferably 4 to 10 times, the thickness t of the thread.
Each thickness may be appropriately selected so as to be doubled. In particular,
The thread 3 is placed at the center of the paper support (that is, the paper support 1).
(The position where D ₁ and D ₂ are completely or almost equal to each other), which is about T / 2 away from the surface a on the heat-sensitive recording layer side).

The thickness of the paper support is not particularly limited, but is preferably about 40 to 250 μm, particularly preferably 60 to 200 μm. When the thickness is less than 40 μm, it is difficult to uniformly feed threads. On the other hand, when the thickness exceeds 250 μm, the reading accuracy for recognizing the thread decreases, and therefore, the forgery prevention performance decreases.

As the paper support, there can be used paper produced from wood pulp such as kraft pulp, sulfite pulp, groundwood pulp, thermomechanical pulp, waste paper pulp, non-wood pulp and the like obtained from ordinary softwoods and hardwoods. .

Examples of the thread- like thread include threads made of natural fibers such as cotton, hemp, and silk, and synthetic fibers such as acrylic resin fibers, polyester resin fibers, and nylon resin fibers. Further, the thread-like thread is preferably made of a dyed thread, a thread having a metal deposition layer, or a thread twisted together with a metal foil, because of excellent anti-counterfeiting properties.

The thickness (diameter) of these thread-like threads is preferably about 10 to 80 μm, particularly preferably about 10 to 40 μm. Incidentally, when the thread-like thread has a dyed layer, a metal deposition layer, a metal foil, etc., the thickness of the paper support,
The thickness (diameter) of the entire yarn including these is three times or more.

Examples of the belt-like thread include a thread made of a synthetic resin film. Specific examples of such a synthetic resin film include, for example, 6,6-nylon film, polyethylene terephthalate film, polyethylene film, polypropylene film and the like.

The belt-shaped thread may be a colored thread, in particular, a thread colored differently from the color of the paper support, aluminum, copper, or the like.
The above synthetic resin film having a metal deposition layer of tin, zinc or the like is excellent in anti-counterfeiting properties and is preferable.

When a synthetic resin film having a metal-deposited layer is used as a belt-shaped thread, the metal-deposited layer may be applied to only one of the front surface and the back surface of the resin film. It may be applied to both the front and back surfaces. In addition, the thickness of the metal deposition layer may be a thickness normally applied for preventing forgery, for example, 0.05 to 1.0.
It may be about μm. A thread made of a resin film having a metal-deposited layer can be manufactured according to a conventional method. For example, various commercially available metal-deposited films having a thickness in the above-mentioned range can be slit into a width in the above-mentioned range.

The width of the belt-shaped thread as described above is 0.3
About 20 mm, particularly preferably about 0.5 to 5 mm, and its thickness (in the case of a metallized film,
(Total thickness of metal deposited layer thickness and resin film thickness)
Is about 10 to 80 μm, preferably about 10 to 40 μm.

When the belt-shaped thread is a resin film having a metal deposition layer, the thickness of the paper support is at least three times the total thickness of the metal deposition layer and the resin film. .

In the present invention, if necessary,
By providing a pressure-sensitive adhesive layer containing a pressure-sensitive adhesive as a main component on at least a part of the thread-like or belt-like thread surface, the bonding between the thread and the pulp fiber in the paper is increased, and the thread is removed from the paper during printing or cutting. The effect of being difficult to remove is enhanced. When a belt-like thread (including a colored thread or a metal-deposited layer) is used, the pressure-sensitive adhesive layer may be applied to one of the front side and the back side of the belt-like thread. It may be applied to both the front and back surfaces.

The pressure-sensitive adhesive in the pressure-sensitive adhesive layer may be any of water-based (water-soluble, latex-based), organic solvent-based, etc., polyester resin, urethane resin, acrylic resin, vinyl acetate resin. And the like. The pressure-sensitive adhesive layer adheres to the paper by contact with water when the thread provided with the thread is applied to a paper support, heating at the time of drying after the paper making, pressurization at the time of super calendering, and the like.

Further, if necessary, by incorporating a fluorescent dye or a fluorescent (phosphorescent) pigment into the pressure-sensitive adhesive layer, the anti-counterfeiting property is further enhanced.

The pressure-sensitive adhesive layer is prepared by uniformly dispersing the above-mentioned pressure-sensitive adhesive and, if necessary, a fluorescent dye and a fluorescent (phosphorescent) pigment using water or an organic solvent as a medium to prepare a coating liquid for the pressure-sensitive adhesive layer. This may be applied and dried by a method such as roll coating, bar coating, or gravure coating. The coating amount of the coating liquid is 1 to 10 g / m on a dry basis.
^{About 2} and especially about ² to 8 g / m ² are preferable.

In the present invention, when the thread-like thread or the belt-like thread has an adhesive layer, the thickness of the paper support is the diameter of the thread-like thread itself excluding the thickness of the adhesive layer or the thickness of the belt-like thread itself. At least three times the thickness.

FIG. 3 shows an example of the thermosensitive recording medium of the present invention provided with a paper support into which a belt-like thread having the above-mentioned metal deposition layer and pressure-sensitive adhesive layer has been formed. 3, the same parts as those in FIG. 1 are indicated by the same reference numerals. In the embodiment shown in FIG. 3, the thread 3 is a metal-deposited film in which metal-deposited layers 4, 4 'are applied to both surfaces of the resin film 3a and the resin film 3a. The thread 3 may be formed by applying only one of the metal deposition layers 4 and 4 ′ to the resin film 3a.

In FIG. 3, the pressure-sensitive adhesive layers 5, 5 '
Are provided on both sides of the thread 3, but the thread 3
It may be provided only on the front surface (the surface on the heat-sensitive recording layer side), or may be provided only on the back surface of the thread 3 (the surface opposite to the heat-sensitive recording layer side).

There is no particular limitation on the method of forming the thread on the paper support, and the method may be performed according to a commonly used method. For example, in a multilayer papermaking machine, a thread-like or a belt-like thread is overlaid, laminated, and dried to join the thread and the paper.

For example, a first paper layer in which a 1 cm × 1 cm hole (window) is opened at intervals of 10 cm is formed on a first circular net of a circular paper machine having three cylinder bats. Insert the thread along the position, then superimpose the second paper layer on one side of the first paper layer without window made by the second mesh and the third paper layer on the other side Thus, a paper support can be obtained by preparing a wet paper serving as a prototype of the paper support and drying it by heating in accordance with a conventional method. Also, at this time, by appropriately adjusting the thicknesses of the first paper layer, the second paper layer, and the third paper layer, it is possible to adjust the threading position.

The thermosensitive recording layer having an electron donating compound and an electron accepting compound includes, for example, a combination of a leuco dye and a color former,
Examples include a combination of a diazonium salt and a coupler, a combination of a chelate compound and a transition element such as iron, cobalt, and copper, and a combination of an imino compound and an aromatic isocyanate compound. It is preferably used because of its excellent concentration. Hereinafter, the thermosensitive recording layer composed of a combination of a leuco dye as an electron donating compound and a color former as an electron accepting compound will be described in detail.

The leuco dye contained in the heat-sensitive recording layer is not particularly limited, but for example, various known dyes can be used. Specific examples of such leuco dyes include, for example, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3-diethylamino-7-anilinofluoran 3-cyclohexylamino-6-chlorofluoran 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-chlorofluorane, 3- (N-ethyl-N-isoamyl) amino-
6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-
7-anilinofluoran, 3-di (n-butyl) amino-6-methyl-7-anilinofluoran, 3-di (n-
Pentyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-7- (o-chloroanilino)
Fluoran, 3-di (n-butyl) amino-7- (o-
Fluoroanilino) fluoran, 3- (N-ethyl-p)
-Toluidino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran, 3,3
-Bis [1- (4-methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-2-yl] -4,
5,6,7-tetrachlorophthalide and the like. Specific examples of the colorant include, for example, 4,4′-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, benzyl 4-hydroxybenzoate, 4,4′-dihydroxydiphenylsulfone, ,
4′-dihydroxydiphenyl sulfone, 4-hydroxy-4′-isopropoxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone,
-Hydroxyphenyl-4'-benzyloxyphenyl sulfone, 1,4-bis [α-methyl-α- (4'-hydroxyphenyl) ethyl] benzene, 2,2'-thiobis (3-tert-octylphenol) and the like Phenolic compounds, thiourea compounds such as N, N'-di-m-chlorophenylthiourea, N- (p-tolylsulfonyl)
Carbamoyl acid-p-cumylphenyl ester, N-
(P- tolyl) carbamoyl acid -p- benzyloxyphenyl ester, N-(p- tolyl sulfonyl) -N '- (p- tolyl) -SO ₂ in the molecule, such as urea
Those having an NH-bond, zinc-[2- (p-methoxyphenoxy) ethyloxy] salicylate, 4- [3-
Zinc salts of aromatic carboxylic acids such as (p-tolylsulfonyl) propyloxy] zinc salicylate and 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] zinc salicylate.

The amount of the leuco dye used is about 5 to 30% by weight, preferably 5 to 30% by weight, based on the total solid content of the heat-sensitive recording layer.
About 20% by weight. The amount of the coloring agent used is about 5 to 40% by weight, preferably about 10 to 30% by weight, based on the total solid content of the heat-sensitive recording layer.

The ratio between the leuco dye and the color former is appropriately selected according to the type of the leuco dye and the color former, and is not particularly limited. 1 to 10 parts by weight, preferably 2 to
About 6 parts by weight of a color former is used.

The heat-sensitive recording layer may contain a storability improver for improving the storage stability of the recording portion and a sensitizer for increasing the recording sensitivity. Specific examples of such a preservability improver include, for example, 2,2′-ethylidenebis (4,6-di-tert-butylphenol), 4,4′-
Thiobis (2-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-
Hindered phenol compounds such as tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 4-benzyloxy-4′- (2-
Examples include epoxy compounds such as methyl glycidyloxy) diphenyl sulfone, diglycidyl terephthalate, phenol novolak type epoxy resin, and bisphenol A type epoxy resin.

Specific examples of the sensitizer include, for example, stearic acid amide, methylenebisstearic acid amide, 2-naphthylbenzyl ether, m-terphenyl, p-benzylbiphenyl, di (p-methoxyphenoxyethyl)
Ether, 1,2-di (3-methylphenoxy) ethane, 1,2-di (4-methylphenoxy) ethane, 1,
2-di (4-methoxyphenoxy) ethane, 1,2-diphenoxyethane, 1,4-di (phenylthio) butane, p-acetotoluizide, p-acetophenethidide,
Examples include N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, di-p-chlorobenzyl oxalate, di-p-methylbenzyl oxalate, dibenzyl oxalate, and the like.

When these preservability improvers and sensitizers are used, their use amounts are not particularly limited, but generally about 1 to 4 parts by weight per 1 part by weight of the color former.

The heat-sensitive recording layer comprises water as a dispersion medium, and a ball mill, an attritor, a leuco dye, a color former, and if necessary, a sensitizer and a storage improver together or separately.
Average particle size of 3μ by agitator / pulverizer such as sand mill
m, preferably 2 μm or less, and then formed by applying and drying a coating solution for a heat-sensitive recording layer prepared by adding at least an aqueous adhesive onto a paper support. Specific examples of the aqueous adhesive added to the heat-sensitive recording layer coating solution include, for example, starches, methyl cellulose, carboxymethyl cellulose, casein, gum arabic, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, silicon polyvinyl Alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride copolymer salt,
Water-soluble adhesives such as ethylene / acrylic acid copolymer salts and styrene / acrylic acid copolymer salts, and urethane resin latex, acrylic resin latex, acrylonitrile / butadiene resin latex, styrene / butadiene resin latex, etc. Water-dispersible adhesive.

The amount of the adhesive used is about 5 to 40% by weight, preferably 8 to 3% by weight based on the total solid content of the heat-sensitive recording layer.
It is about 0% by weight.

Further, various auxiliaries can be added to the heat-sensitive recording layer coating liquid, if necessary. For example, kaolin, calcium carbonate, calcined kaolin, amorphous kaolin having an average particle diameter of about 0.1 to 5 μm, amorphous Silica, aluminum hydroxide, urea
Pigments such as formalin resin fillers, dispersants such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, fatty acid metal salts, zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, etc. Waxes, antifoaming agents, crosslinking agents, coloring dyes and the like.

The coating amount of the heat-sensitive recording layer coating solution may be appropriately selected from a wide range, but generally, on a dry basis,
It is recommended to be about 3 to 15 g / m ² , preferably about 4 to 10 g / m ² .

Protective Layer If necessary, a protective layer containing a film-forming adhesive may be provided on the heat-sensitive recording layer. The protective layer is, for example, mixed with an adhesive that can be contained in the heat-sensitive recording layer coating liquid and an auxiliary agent (particularly, the pigment) that can be added to the heat-sensitive recording layer coating liquid, if necessary, using water as a medium. The coating liquid for a protective layer prepared by stirring is coated on the heat-sensitive recording layer and dried to form a coating.

The amount of the adhesive used is about 20 to 90% by weight, preferably about 20 to 70% by weight, based on the total solid content of the protective layer. The amount of the auxiliary (particularly, pigment) used is
It is about 10 to 70% by weight, preferably about 30 to 60% by weight, based on the total solid content of the protective layer.

The coating amount of the coating liquid for the protective layer may be appropriately selected from a wide range.
6 g / m ² approximately, preferably recommended that a 2-5 g / m ² approximately.

Intermediate Layer In the present invention, if necessary, an intermediate layer mainly composed of a pigment and an adhesive can be provided between the paper support and the heat-sensitive recording layer. Rolling of the rolls when the paper is loose and the heat-sensitive recording paper is wound is significantly suppressed.

The pigment has an average particle diameter of 0.1 to
Inorganic pigments such as calcium carbonate, kaolin, talc, calcined kaolin, amorphous silica, synthetic aluminum silicate, zinc oxide, titanium oxide, and aluminum hydroxide of about 5 μm, or urea formalin having an average particle diameter of about 0.5 to 30 μm Organic pigments such as resin filler, hollow acrylic resin filler, hollow styrene resin filler, and hollow vinylidene chloride resin filler are exemplified. In particular,
Organic hollow particles such as a hollow acrylic resin filler, a hollow styrene resin filler, and a hollow vinylidene chloride resin filler having good cushioning properties are preferred. The amount of the pigment used is 3 to the total solid content of the intermediate layer.
About 0 to 90% by weight, particularly about 40 to 80% by weight is preferable.

The adhesive used for the intermediate layer includes those which can be used in the above-mentioned heat-sensitive recording layer. The amount of the adhesive used is preferably about 5 to 30% by weight, particularly preferably about 10 to 25% by weight, based on the total solid content of the intermediate layer.

The intermediate layer is prepared, for example, by mixing and stirring the above-mentioned pigment, adhesive and, if necessary, an auxiliary agent which can be added to the heat-sensitive recording layer coating liquid, using water as a medium. It is formed by coating and drying on the front side of the paper support (the surface on the side of the heat-sensitive recording layer).

The coating amount of the coating solution for the intermediate layer may be appropriately selected from a wide range, but is generally 5 to 15 on a dry basis.
g / m ² approximately, preferably recommended that a 6 to 12 g / m ² approximately.

As a method for applying each coating solution for the heat-sensitive recording layer, the intermediate layer and the protective layer, for example, an air knife method,
Examples include a Meyer bar system, a pure blade, a system rod blade system, a reverse roll system, a gravure system, a slit die system, and a curtain system.

The heat-sensitive recording medium of the present invention can be added with various known paper processing techniques such as providing a magnetic recording layer.

[0053]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but it should be understood that the present invention is by no means restricted thereto. Unless otherwise specified, parts and% in the examples are parts by weight and% by weight, respectively.

Example 1 (1) Preparation of Solution A 10 parts of 3-di (n-butyl) amino-6-methyl-7-anilinofluoran, sulfone-modified polyvinyl alcohol (trade name: Goselan L-3266, Nippon Gosei) A composition consisting of 5 parts of a 10% aqueous solution of water and 25 parts of water (manufactured by Chemical Industry Co., Ltd.) was pulverized with a sand mill until the average particle diameter became 0.8 μm to obtain a liquid A.

(2) Preparation of Solution B 10 parts of 4-hydroxy-4'-isopropoxydiphenyl sulfone, sulfone-modified polyvinyl alcohol (trade name: Goselan L-3266, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
A composition comprising 5 parts of a 10% aqueous solution of water and 25 parts of water was pulverized with a sand mill until the average particle diameter became 1.5 μm to obtain a liquid B.

(3) Preparation of Solution C 10 parts of 1,2-di (3-methylphenoxy) ethane, 5 parts of a 10% aqueous solution of sulfone-modified polyvinyl alcohol (trade name: Goselan L-3266, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) And a composition comprising water and 25 parts of water were pulverized with a sand mill until the average particle diameter became 1.0 μm to obtain a liquid C.

(4) Preparation of Coating Solution for Thermosensitive Recording Layer 50 parts of solution A, 100 parts of solution B, 100 parts of solution C, light calcium carbonate (Brilliant 15: made of calcium shiraishi) 20
Part, SBR latex (L-1571: manufactured by Asahi Kasei) 20
Parts, zinc stearate dispersion (hydrin Z-7-3)
(0, manufactured by Chukyo Yushi Co., Ltd.) and 30 parts of water were mixed and stirred to obtain a coating liquid for a heat-sensitive recording layer.

(8) Preparation of Coating Solution for Intermediate Layer Average particle system 1 μm, hollowness (ratio of inner diameter to outer diameter)
100 parts of a 40% dispersion of 70% styrene hollow particles,
40 parts of a 10% aqueous solution of polyvinyl alcohol, 10 parts of a styrene-butadiene latex having a solid content of 50%,
A composition comprising 20 parts of calcined kaolin having an oil absorption of 110 ml / 100 g, 5 parts of calcium carbonate having an average particle diameter of 1 μm and 50 parts of water was mixed and stirred to obtain a coating liquid for an intermediate layer.

(9) Preparation of Thread A polyethylene terephthalate (PET) film on both surfaces of which aluminum is vacuum-deposited (thickness including a deposition layer: 1)
Urethane resin adhesive (trade name: Superflex 750, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) on both sides of a gravure roll coater having a dry weight of 3 g / m 2
^It was applied and dried to obtain ² . Next, a slit was formed to a width of 3 mm with a microslitter and wound on a bobbin to obtain a thread.

(10) Preparation of Paper Support The first paper layer of a circular paper machine provided with three tanks of cylinder vats, in which 1 cm × 1 cm (windows) with 1 cm (windows) open at 10 cm intervals, was used. Paper was made and the above thread was inserted along the position of the window. Next, one side of the first paper layer is overlaid with a second paper layer on the entire surface without a window made of a second circular net, and the third paper layer is superimposed on the other side, and the original paper support is formed. Wet paper (moisture 50%) is prepared and a Yankee dryer (surface temperature:
(70 ° C.) and four cylinder dryers (surface temperature: about 70 to 90 ° C.) to obtain a paper support having a moisture content of 5% and a thickness of 60 μm. In this paper support,
The thread was cut almost in the center of the thickness of the paper support.

(11) Preparation of heat-sensitive recording paper On one side of the paper support obtained in the above (10),
And the heat-sensitive recording layer obtained in (4) above.
The coating amount after drying the coating solution is 8.0 / m each. ^Two, 6.
0 g / m^TwoCoat and dry so that
After providing the thermal recording layer, super calendering
A thermal recording paper was obtained.

Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the following paper support was used instead of the paper support used in the preparation of the thermosensitive recording paper of Example 1.

(1) Preparation of Paper Support A first paper layer of a circular paper machine equipped with three cylinder bats, the first paper layer having 1 cm × 1 cm holes (windows) open at 10 cm intervals. Was made into a paper, and a thread made of a silk gold thread (silk thread deposited with gold; 40 μm in thickness (diameter) including a gold deposition layer) was inserted along the position of the window. Next, one side of the first paper layer is overlaid with a second paper layer on the entire surface without a window made of a second circular net, and the third paper layer is superimposed on the other side, and the original paper support is formed. Wet paper (moisture 50%) is prepared and dried by passing through a Yankee dryer (surface temperature: about 70 ° C.) and four cylinder dryers (surface temperature: about 70 to 90 ° C.), moisture content 5%, thickness A 180 μm paper support was obtained. In this paper support, the thread was formed substantially at the center in the thickness direction of the paper support.

Example 3 A protective layer was formed by applying the following coating liquid for a protective layer on the heat-sensitive recording layer of Example 1 so that the coating amount after drying was 2.5 g / m ^2. Then, a super calender treatment was performed to obtain a thermosensitive recording paper.

(1) Preparation of Coating Solution for Protective Layer 200 parts of a 12% aqueous solution of acetoacetyl-modified polyvinyl alcohol (trade name: Gosefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), kaolin (trade name: Ultra White) 90, manufactured by Engelhard Co.), 30 parts of 30% zinc stearate dispersion (hydrin Z-7-30: manufactured by Chukyo Yushi), 2 parts of polyamide epichlorohydrin resin-based cross-linking agent (PA-801: manufactured by Nippon PMC) and Water 21
0 parts of the composition was mixed and stirred to obtain a coating liquid for a protective layer.

Comparative Example 1 In the preparation of the thread of Example 1, instead of a PET film (thickness including a vapor deposition layer: 12 μm) on which aluminum is vacuum-deposited on both sides, a PET film on which aluminum is vacuum-deposited on both sides (Thickness including vapor deposition layer: 30
μm) was used in the same manner as in Example 1 to obtain a thermosensitive recording paper.

The obtained thermosensitive recording paper was evaluated by the following methods, and the results are shown in Table 1.

[0068] Bokotsuki winding a heat-sensitive recording paper obtained, respectively (width 40 cm, length 50m, core diameter 5 cm) was visually observed Bokotsuki state. ：: There is almost no waving due to bumps in the winding. ×: Rippling due to unevenness is strongly generated during winding.

Recording Quality The obtained thermal recording paper was transferred to a thermal recording medium evaluation machine (trade name: TH).
-PMD type, manufactured by Okura Electric Co., Ltd.) at an applied energy of 0.2 mJ / dot, and a recorded image of a recording portion, particularly a portion where a thread was formed, was visually judged using a loupe (× 10). . A: Almost no missing dots were observed. ：: Some missing dots were observed. ×: A lot of missing dots are seen.

[0070]

[Table 1]

[0071]

The heat-sensitive recording paper of the present invention has the effect of reducing unevenness even on a support for which forgery prevention measures have been taken, and of having excellent recording image quality.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thermosensitive recording medium according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a paper support into which a thread used in the present invention has been formed.

FIG. 3 is a cross-sectional view showing an example of the thermosensitive recording medium of the present invention provided with a paper support into which a belt-shaped thread having a metal deposition layer and an adhesive layer is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper support 2 Thermal recording layer 3 Thread 3a Synthetic resin film 4, 4 'Metal deposition layer 5, 5' Adhesive layer a Front side of paper support b Back side of paper support c Front of thread d Thread back

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C005 HA02 HA04 HA06 HA09 HB10 HB11 HB12 HB13 JB28 JC03 KA40 LA26 2H026 AA07 BB02 BB21 EE03 FF01 FF13

Claims (5)

[Claims] 1. A heat-sensitive recording paper having a heat-sensitive recording layer containing an electron-donating compound, an electron-accepting compound and an adhesive on a paper support, wherein a thread or a belt-like thread is formed in the paper support. A thermosensitive recording paper, wherein the thickness of the paper support is rare and at least three times the diameter of the thread-like thread or the thickness of the belt-like thread. 2. The heat-sensitive recording paper according to claim 1, wherein the thickness of the paper support is 40 to 250 μm. 3. The heat-sensitive recording paper according to claim 1, wherein the belt-like thread is a synthetic resin film having a metal deposition layer. 4. An intermediate layer containing a pigment or organic hollow particles between a paper support and a heat-sensitive recording layer.
4. The heat-sensitive recording paper according to any one of 1. to 3. 5. The heat-sensitive recording paper according to claim 1, wherein an adhesive layer mainly composed of an adhesive is provided on at least a part of the surface of the thread-like or belt-like thread.