JP5342545B2 - Invisible information printing sheet - Google Patents

Description

  The present invention relates to an invisible information printing sheet that visualizes invisible information that has been printed in advance by developing a color by physical or chemical action.

As an invisible information printing sheet, for example, a scratch lot application is known. They are generally invisible information printing sheets in which information such as letters, numbers, and other patterns indicating winning is printed on a sheet such as paper and further covered with a concealing layer to make the information invisible. Specifically, after printing visible information or the like on a sheet of paper or the like, and further printing information to be invisible, a release agent layer is provided to cover the information to be invisible, and a concealing silver color is provided thereon. It is used in such a manner that invisible information appears by scraping the scratch ink with a coin or the like.
However, there is a drawback in that scraps generated when removing the scratch ink described above become dust, and the use and place of use are limited. In addition, the color of the scratch ink is dark, and it tends to be dark and tends to be a design problem.

  In order to solve the above problems, it is easy to express invisible information without using a concealing scratch ink, and it is possible to suppress the generation of shavings, including colorless or light-colored electron-donating dye precursors and varnishes. What was obtained by mixing an electron-donating dye precursor ink base for scratch color development and an electron-accepting developer ink base for scratch color development containing an electron-accepting developer and varnish separately with a dryer Scratch coloring inks and invisible information printing sheets using them have been proposed (for example, see JP-A-2006-199887). Invisible information before color development is not visible at all with normal size letters and numbers, but it is also possible to handle larger letters and patterns, or to further increase the color density while maintaining invisibility. Has been.

  Further, the use of the invisible information print sheet includes authenticity determination. In this case, the color is developed by heat or by scratching (for example, see Japanese Patent Application Laid-Open No. 2006-290975), and a clearer color is required for authenticity determination.

  Even invisible information such as large characters is not visible, and the invisible information printed part is difficult to color by rubbing during normal handling, and invisible information can be easily visualized by simply rubbing with a nail, when invisible information is visualized It is an object to provide an invisible information printing sheet that is free from shavings and that can provide a clear color image, especially when it is visualized.

As a result of intensive studies by the present inventors, a printed portion using a scratch coloring ink containing a colorless or light-colored electron-donating dye precursor, an electron-accepting developer and a varnish is provided on the support. In the invisible information printing sheet, the support contains a pigment and a binder on the side on which the printed portion using the scratch coloring ink is provided, and the coating amount is 3.0 g / m ² to 6. It has been found that the above problem can be solved by using a coating support provided with a pigment coating layer of 0 g / m ² .

That is, the present invention
(1) In an invisible information printing sheet in which a printed portion using a scratch coloring ink containing a dye precursor, an electron accepting developer and a varnish is provided on a support, the support is scratch colored. A pigment coating layer containing a pigment and a binder and having a coating amount of 3.0 g / m ² to 6.0 g / m ² was provided on the side on which the printing portion using the ink for printing was provided. Invisible information printing sheet, characterized by being a coating support,
( 2 ) The invisible information printing sheet according to (1 ), wherein in the pigment coating layer, the mass ratio of the pigment and the binder is 5 to 30 parts by mass of the binder with respect to 100 parts by mass of the pigment.
( 3 ) The invisible information printing sheet according to (1) or 2 , wherein the pigment is at least one selected from kaolin clay, calcined clay, light calcium carbonate, heavy calcium carbonate, aluminum hydroxide, and talc.
( 4 ) The invisible information printing sheet according to any one of (1) to ( 3 ), wherein the Mohs hardness of the pigment is 3.5 or less,
( 5 ) The invisible information printing sheet according to any one of (1) to ( 4 ), wherein the average particle diameter of the pigment is 0.02 to 5 μm,
( 6 ) The invisible information printing sheet according to any one of (1) to ( 5 ) above, wherein the smoothing smoothness of the coating support is 1.0 to 85.0 kPa, and ( 7 ) for pigment coating The invisible information printing sheet according to any one of (1) to ( 6 ), wherein the basis weight of the base material is 40 to 450 g / m ² .
Is to provide.

  The invisible information printing sheet of the present invention can visualize invisible information clearly even by rubbing with a nail, hardly cause color stains due to rubbing during normal handling, no shaving residue, and invisible in a state before color development. The property is also good.

Hereinafter, the invisible information printing sheet of the present invention will be described more specifically.
The present invention contains a colorless or light-colored electron-donating dye precursor (hereinafter abbreviated as a dye precursor), an electron-accepting developer (hereinafter abbreviated as a developer), and a varnish on a support. In the invisible information printing sheet provided with a printing portion using the scratch coloring ink, the support contains a pigment and a binder on the surface on which the printing portion using the scratch coloring ink is provided, invisible information printed sheet, characterized in that the coating weight of the coating support provided with pigment coating layer is ^{0.5g / m 2 ~6.5g / m 2} .

The invisible information printed sheet of the present invention, as a support contains a pigment and a binder, coating the coating amount is provided a pigment coating layer is 0.5g ^/ m ² ~6.5g / m 2 A support is used. The printing portion using the scratch coloring ink is provided on the surface on which the pigment coating layer is provided. When providing a printed portion by the scratch color ink to both sides of the support, the double side coating support provided with pigment coating layer on both surfaces coating amount 0.5g ^/ m ² ~6.5g / m 2 When used, the effects of the present invention are preferably obtained on both sides. Paper is easily available as a base material for pigment coating. Other examples of the base material preferably used include various woven fabrics, nonwoven fabrics, synthetic resin films, synthetic resin laminated papers, synthetic papers, metal foils, vapor deposition sheets, and composite sheets obtained by combining them together. The coating support or its substrate may contain a fluorescent whitening agent, an ultraviolet absorber, an antioxidant, and the like, if necessary. As the ultraviolet absorber and the antioxidant, an after-mentioned scratch coloring ink is used. The thing similar to what can be included as needed is mentioned.
In addition, when a printed part with a scratch coloring ink is provided on one side of the support, on the opposite side, if necessary, a thermal recording layer, a dye precursor-encapsulated microcapsule-containing layer for pressure-sensitive copying, A fixing layer, a magnetic recording layer, an adhesive layer, a resin coating layer, a pigment coating layer, and the like for ink jet recording may be provided.

In the present invention, when a coating support is used, the appearance and opacity are good, the scratch property (ease of rubbing), the color developability (color sensitivity) and the color density due to the scratch are improved, and the color developed during handling. Dirt is also improved, which is preferable. However, there is a drawback that even the printed portion before the color development of the scratch becomes easy to visually recognize, and the invisibility becomes slightly worse. In order to maintain the invisibility at a high level, it was necessary to sacrifice other advantages such as lowering the color density. However, by making the coating amount 6.5 g / m ² or less, preferably 6.0 g / m ² or less, not only the invisibility can be remarkably improved, but also the color density can be kept remarkably high. . Even if this upper limit value is slightly exceeded, it is difficult to obtain the effects of the present invention. On the other hand, when the coating amount is less than 0.5 g / m ² , the production of the coating support cannot be stably performed. If further stabilization is desired, it is preferably 2.0 g / m ² or more, more preferably 2.5 g / m ² or more, and the opacity and scratch properties seen in the above-mentioned coating support are also preferable. Kept. Accordingly, in the present invention, the coating weight is limited to ^{0.5g / m 2 ~6.5g / m 2} , preferably 0.5g ^/ m 2 ~6.0g ^/ m, more preferably from 2.0g / M ^{2 to} 6.0 g / m, particularly preferably 2.5 g / m ^{2 to} 6.0 g / m. It has been difficult to predict from the known knowledge of commercial printing coating supports and the like that a coating support in such a narrow coating amount range is used for an invisible information printing sheet and a favorable effect is obtained.

  In the pigment coating layer, the mass ratio of the pigment and the binder is 5 to 30 parts by mass, more preferably 10 to 20 parts by mass with respect to 100 parts by mass of the pigment. It has been found that the color developability (color development sensitivity) and color density due to scratches are improved, and color stains during handling are also improved, which is preferable. When the mass ratio of the binder is less than the preferred range, the coating layer may be peeled off by scratching to generate white powder. Also, part of the coating layer is peeled off during printing, and troubles such as blanket stains occur. On the other hand, when the mass ratio of the binder is larger than the preferable range, the adhesion state of the scratch coloring ink to the pigment coating layer may be deteriorated during printing. In particular, when there is a film formation on the surface, there is a possibility that the infiltration of the ink is worsened and the invisibility is lowered.

  The pigments contained in the pigment coating layer include kaolin clay, diatomaceous earth, talc, calcined clay, light calcium carbonate, heavy calcium carbonate, precipitated calcium carbonate, light magnesium carbonate, heavy magnesium carbonate, chalk, zinc oxide, Inorganic pigments such as aluminum oxide, aluminum hydroxide, magnesium hydroxide, titanium dioxide, barium sulfate, zinc sulfate, amorphous silica, amorphous calcium silicate, vapor phase silica, colloidal silica, alumina, melamine resin filler, One or more kinds selected from organic pigments such as urea-formalin resin filler, polyethylene powder, nylon powder and starch can be mentioned. Normally, a white pigment is used, but a colored pigment may be used.

It is preferable that the Mohs hardness of the pigment contained in the pigment coating layer is low. If the Mohs hardness is 4 or less, more preferably 3.5 or less, it is preferable that a portion other than the invisible information printing portion does not darken when the scratch is developed using a coin. In particular, at least one selected from kaolin clay, calcined clay, light calcium carbonate, heavy calcium carbonate, aluminum hydroxide, and talc is preferable from the balance of coating suitability, color developability, and invisibility.
However, a pigment having a Mohs hardness of 4 or more may be used in order to leave a trace of scratches caused by coins.

  Binders used in the pigment coating layer include starches, hydroxymethylcellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium alginate, polyvinylpyrrolidone, polyacrylamide, acrylamide / acrylic acid ester Polymer, acrylamide / acrylic ester / methacrylic acid terpolymer, alkali salt of polyacrylic acid, alkali salt of polymaleic acid, alkali salt of styrene / maleic anhydride copolymer, ethylene / maleic anhydride copolymer Water-soluble binder such as alkali salt, alkali salt of isobutylene / maleic anhydride copolymer, and styrene / butadiene copolymer, acrylonitrile / butadiene copolymer Methyl acrylate / butadiene copolymer, acrylonitrile / butadiene / styrene terpolymer, polyvinyl acetate, vinyl acetate / acrylate copolymer, ethylene / vinyl acetate copolymer, polyacrylate, styrene / acryl 1 type or more chosen from water-dispersible binders, such as an acid ester copolymer and a polyurethane, is mentioned.

In the case of a coating support, the glossiness can be adjusted widely. For example, when it is desired to lower the glossiness, it is achieved by using a pigment having a large average particle diameter in the pigment coating layer or increasing the pigment content ratio. However, if the average particle diameter of the pigment is too large, the surface on which the scratch coloring ink is printed becomes rough, and the print information tends to be unclear. Conversely, when it is desired to increase the glossiness, it is achieved by reducing the average particle diameter of the pigment, but it is difficult to obtain an extremely small average particle diameter. The average particle diameter of a preferable pigment is 0.02 to 5 μm, more preferably 0.3 to 4 μm.
Also, the glossiness can be adjusted by the surface treatment of the pigment coating layer, for example, super calender, soft calender, etc., depending on the treatment conditions.
When invisibility is particularly important, it is preferable to reduce the smoothness of the coating support. A smoother smoothness of 1.0 kPa or more, more preferably 10.0 kPa or more, and particularly 30.0 kPa or more is preferred from the viewpoint of invisibility. Further, smooth smoothness of 85.0 kPa or less, more preferably 80.0 kPa or less, and particularly preferably 75.0 kPa or less is preferable because there is little printing unevenness. The smoother smoothness measurement may be performed on the coating support before printing or after performing various printings as an invisible information printing sheet. In the case of a coating support for double-sided coating, the surface to be measured is the surface on which the scratch coloring ink is provided.

In many cases, paper is used as a base material for pigment coating, and will be described. There are no particular restrictions on the thickness or basis weight of the paper as the base material, but from the viewpoint of ease of handling, such as it is difficult to tear when the printed part using the scratch coloring ink is rubbed, and it does not wrinkle. The basis weight is preferably 40 g / m ² or more, more preferably 60 g / m ² or more, and still more preferably 80 g / m ² or more. There is no particular upper limit to the basis weight, and paperboard may be used as the base material. The paperboard provided with the pigment coating layer is easily available as white paperboard, for example. However, when the invisible information printing sheet of the present invention is used in the form of a card or a package, the basis weight of the base material is usually 450 g / m ² or less, particularly 350 g / m ² or less, and further 250 g / m ^2. The following is preferable because it is not bulky.

  Wood pulp used for paper as a base material includes chemical pulp such as kraft pulp, alkali pulp, sulfite pulp, semi-chemical pulp, semi-mechanical pulp, mechanical pulp and the like obtained from hardwoods and conifers. Waste paper pulp that has undergone dust removal and deinking processes can also be used. Using these, high-quality paper and medium-quality paper are manufactured and used by a paper machine, but since they are rubbed with a nail or a coin, a certain degree of physical strength is required.

  If necessary, the paper as the base material may contain a filler, a sizing agent, a paper strength enhancer and the like. The filler is not particularly limited, and white pigments such as talc, clay, calcined clay, calcium carbonate, and amorphous silica can be used, and these can be used in combination.

  Since a pigment coating layer is provided on paper as a base material, a sizing agent is usually not used in many cases. When used, the sizing agent is not particularly limited, and is used for acidic paper and neutral paper mainly composed of neutral rosin, alkyl ketene dimer, alkenyl succinic anhydride, petroleum resin, etc. that are generally used as internal sizing agents. A sizing agent can be used as appropriate.

The scratch coloring ink used in the present invention contains a dye precursor, a developer and a varnish. In order for the dye precursor and the developer to be in a substantially uncolored state, it is more preferable that each of them is contained as solid particles in the scratch coloring ink.
The components contained in the scratch coloring ink will be described. The dye precursor contained in the scratch coloring ink used in the present invention is typically represented by those used in pressure-sensitive recording materials and heat-sensitive recording materials, but is not particularly limited.

As an example of a specific dye precursor,
(1) Triarylmethane compounds or compounds having an indolyl group: 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 3,3-bis (4-dimethylamino) Phenyl) phthalide, 3- (4-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3- (4-dimethylaminophenyl) -3- (2-methylindole-3- Yl) phthalide, 3- (4-dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylamino Phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (1-butyl) Ru-2-methylindol-3-yl) phthalide, 3,3-bis (9-ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) ) -5-dimethylaminophthalide, 3- (4-dimethylaminophenyl) -3- (1-methylpyrrol-2-yl) -6-dimethylaminophthalide, 3- (1-ethyl-2-methylindole) -3-yl) -3- (2-ethoxy-4-dimethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-) Diethylaminophenyl) -4-azaphthalide, etc.

  (2) Diphenylmethane compounds: 4,4′-bis (dimethylaminophenyl) benzhydrylbenzyl ether, N-chlorophenylleucooramine, N-2,4,5-trichlorophenylleucooramine, etc.

  (3) Xanthene compounds: Rhodamine B anilinolactam, rhodamine Bp-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino- 7-phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane, 3-diethylamino -7- (2-chloroanilino) fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-dipentylamino-6-methyl- 7-anilinofluorane, 3- (N-ethyl-Np-tolyl) Mino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3- (N-ethyl-Np-tolyl) amino-6-methyl-7-phenethyl Fluorane, 3-diethylamino-7- (4-nitroanilino) fluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-propyl) amino-6-methyl-7 -Anilinofluorane, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-ani Linofluorane, 3- (N-ethyl-N-tetrahydrofurfuryl) amino-6-methyl-7-anilinofluorane, 3,6-dimethoxyfluorane, 3-cyclohexyla Roh-6-chloro-full Oran, etc.,

  (4) Thiazine compounds: benzoyl leucomethylene blue, 4-nitrobenzoyl leucomethylene blue, etc.

  (5) Spiro compounds Other compounds: 3-methylspirodinaphthopyrans, 3-ethylspirodinaphthopyrans, 3,3′-dichlorospirodinaphthopyrans, 3-benzylspirodinaphthopyrans, 3-methylnaphtho -(3-methoxybenzo) spiropyran, 3-propylspirobenzopyran, 2,6-diphenyl-4- (4-dimethylaminophenyl) -pyridine, 2,2-bis (4- (2- (4-diethylaminophenyl) ) Quinazolyl) oxyphenyl) propane, 4-chloro-N- (4- (N- (4-methylbenzyl) -N-methylamino) benzylidene) aniline, 1- (2-quinolyl) -2- (3-methoxy -4-dodecyloxyphenyl) ethene and the like. These dye precursors can be used alone or in combination of two or more as required. Xanthene compounds are preferred from the viewpoint of color change prevention and color development sensitivity of scratch coloring inks, and triarylmethane compounds or compounds having indolyl groups are also preferred because of their vibrant hues.

  The developer contained in the scratch coloring ink used in the present invention is generally represented by an acidic substance used in a pressure-sensitive recording material or a heat-sensitive recording material, but is not limited thereto. For example, phenol derivatives, aromatic carboxylic acid derivatives, N, N′-diarylthiourea derivatives, arylsulfonylurea derivatives, sulfonamide derivatives, polyvalent metal salts such as zinc salts of organic compounds, benzenesulfonamide derivatives, etc. Can do.

  Specific examples include 4,4′-dihydroxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, 4-hydroxy-4′-benzyloxydiphenylsulfone, 4-hydroxy-4'-propoxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 3,4-dihydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-benzenesulfonyloxydiphenylsulfone, Examples thereof include diphenylsulfone compounds such as 2,4-di (phenylsulfonyl) phenol.

  Other specific examples include 4-phenylphenol, 4-hydroxyacetophenone, 1,1-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) pentane, 1,1-bis (4 -Hydroxyphenyl) hexane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) hexane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,3- Bis [2- (4-hydroxyphenyl) -2-propyl] benzene, 1,3-bis [2- (3,4-dihydroxyphene) ) -2-propyl] benzene, 1,4-bis [2- (4-hydroxyphenyl) -2-propyl] benzene, 4,4'-hydroxydiphenyl ether,

  3,3'-dichloro-4,4'-hydroxydiphenyl sulfide, methyl 2,2-bis (4-hydroxyphenyl) acetate, butyl 2,2-bis (4-hydroxyphenyl) acetate, 4,4'-thiobis (2-t-butyl-5-methylphenol),

  N- (2-hydroxyphenyl) benzenesulfonamide, N- (2-hydroxyphenyl) -p-toluenesulfonamide, N- (2,4-dihydroxyphenyl) benzenesulfonamide, N- (2,4-dihydroxyphenyl) ) -P-toluenesulfonamide, N- (2-hydroxynaphthyl) benzenesulfonamide, N- (2-hydroxynaphthyl) -p-toluenesulfonamide, N- (2-hydroxyphenyl) -1-naphthalenesulfonamide, N- (2-hydroxyphenyl) -2-naphthalenesulfonamide, N- (2-hydroxynaphthyl) -1-naphthalenesulfonamide, N- (2-hydroxynaphthyl) -2-naphthalenesulfonamide, N- (2- Hydroxyphenyl) -p-chlorobenzenesulfonamide N- (2-hydroxyphenyl) -p-methoxybenzenesulfonamide, N- (2-hydroxyphenyl) -p-allylbenzenesulfonamide, N- (2-hydroxyphenyl) -p-phenylbenzenesulfonamide, 4, 4'-bis (2-hydroxyphenylaminosulfonyl) diphenylmethane, N- (2-hydroxyphenyl) -N-methylbenzenesulfonamide, N- (2-hydroxyphenyl) -N-methyl-p-toluenesulfonamide, N -(2-hydroxyphenyl) -N-benzyl-p-toluenesulfonamide, N- (2-hydroxyphenyl) -N-allyl-p-toluenesulfonamide, N- (2-hydroxyphenyl) -N-phenylbenzene Sulfonamide,

  Dimethyl 4-hydroxyphthalate, benzyl 4-hydroxybenzoate, methyl 4-hydroxybenzoate, benzyl gallate, stearyl gallate, N, N'-diphenylthiourea, 4,4'-bis [3- (4- Methylphenylsulfonyl) ureido] diphenylmethane, N- (4-methylphenylsulfonyl) -N'-phenylurea, salicylanilide, 5-chlorosalicylanilide, salicylic acid, 3,5-di-t-butylsalicylic acid, 3,5- Di-α-methylbenzylsalicylic acid, 4- [2 ′-(4-methoxyphenoxy) ethyloxy] salicylic acid, 3- (octyloxycarbonylamino) salicylic acid or metal salts of these salicylic acid derivatives, N- (4-hydroxyphenyl)- p-Toluenesulfonamide, N- (4-hydroxy Enyl) benzenesulfonamide, N- (4-hydroxyphenyl) -1-naphthalenesulfonamide, N- (4-hydroxyphenyl) -2-naphthalenesulfonamide, N- (4-hydroxynaphthyl) -p-toluenesulfonamide N- (4-hydroxynaphthyl) benzenesulfonamide, N- (4-hydroxynaphthyl) -1-naphthalenesulfonamide, N- (4-hydroxynaphthyl) -2-naphthalenesulfonamide, N- (3-hydroxyphenyl) ) -P-toluenesulfonamide, N- (3-hydroxyphenyl) benzenesulfonamide, N- (3-hydroxyphenyl) -1-naphthalenesulfonamide, N- (3-hydroxyphenyl) -2-naphthalenesulfonamide, etc. Is mentioned. In particular, a diphenylsulfone compound is preferred from the viewpoint of discoloration prevention and color development sensitivity of the scratch coloring ink.

  The varnish contained in the scratch coloring ink used in the present invention contains a binder resin and, if necessary, an oil, a solvent and the like.

  Specific examples of binder resins contained in the varnish include, for example, natural resins such as rosin, natural resin derivatives such as cured rosin and rosin ester, and alkyd resins, polyamide resins, acrylic resins, polyvinyl chloride, polyvinyl acetate, Styrene resins, epoxy resins, cellulose derivatives, phenol resins, rosin-modified phenol resins, xylene resins, melamine resins, urea resins, ketone resins, rosin-modified maleic acid resins, petroleum resins made from unsaturated hydrocarbons such as olefins, etc. Synthetic resins are mentioned.

Specific examples of oils contained in the varnish as necessary include vegetable oils such as linseed oil, rapeseed oil, coconut oil, olive oil, soybean oil, tung oil, etc., and vegetable oils, spindle oils, machine oils obtained by regenerating these, Examples include mineral oils such as mobile oil.
In the present invention, the nonvolatile organic liquid is called oil and the volatile organic liquid is called a solvent.

Specific examples of the solvent contained in the varnish as needed include, for example, aromatic solvents such as toluene and xylene, ester solvents such as ethyl acetate and isopropyl acetate, ketone solvents such as acetone and methyl ethyl ketone, and methyl alcohol. And alcohol solvents such as isopropyl alcohol and n-propyl alcohol, aliphatic hydrocarbons such as n-hexane, n-heptane and cyclohexane, and glycol solvents such as ethylene glycol and diethylene glycol.
In addition, petroleum-based solvents containing 1% by mass or less of aromatic components mainly composed of paraffin and naphthenic compounds are non-volatile, but are contained as necessary in the same manner as volatile solvents.

  The scratch coloring ink used in the present invention may further contain various auxiliary agents. For example, dryers such as cobalt naphthenate and manganese octylate as drying accelerators, chelating agents commonly referred to as aluminum chelates, adjusting agents such as petroleum solvents and varnishes that adjust the viscosity of the ink, and adjusting the slip after printing Contains sensitizers such as waxes, surfactants, organic and inorganic fine particles, fatty acid amides, aliphatic urea compounds, ether compounds, ester compounds, and biphenyl derivatives known for heat-sensitive recording materials to increase the color density. You may let them.

In the scratch coloring ink used in the present invention, the mass ratio (% by mass) of the developer to the dye precursor is preferably from 50 to 1000% by mass, particularly from 100 to 500% by mass, from the stain and color developability of the printed part. preferable. Also, if the dye precursor and the developer are simultaneously added to the vehicle (varnish) in a predetermined ratio and kneaded, the dye precursor may develop color and cause ink coloring. It is preferable to sufficiently mix the ink at a predetermined ratio with a stirrer or the like after the conversion to the ink, which can reduce ink coloring due to contact between the dye precursor and the developer, etc., and is preferable for making the printed portion invisible. The type of vehicle (varnish) and the varnish content in the scratch coloring ink differ depending on the printing method, but preferably 10 to 90% by weight, more preferably 60 to 85% by weight, and still more preferably 65 to 85% by weight of the scratch coloring ink. It is appropriately selected within the range of 85% by mass.
In addition, when the individual components are kneaded separately at the time of producing the scratch coloring ink, they are referred to as an ink base.

  The varnish in the scratch coloring ink used in the present invention may be prepared by a conventionally known method. For example, a binder resin and, if necessary, composition components such as oil to be contained are dissolved by heating, and then a solvent is used as necessary. And an aluminum chelating agent or the like.

  Next, the method for obtaining the invisible information print sheet will be described. Normal printing may be performed on the invisible information printing sheet of the present invention. In this case, various printing inks can be used, but it is also possible to use an ink having a hue different from the coloring hue of the scratch coloring ink or the hue of the support surface. If the hue of the support surface is white and the color of the scratch coloring ink is black or blue, an ink having a high brightness such as yellow or orange is preferable.

  In order to print the invisible information of the invisible information printing sheet of the present invention, it is produced using various printing methods such as offset printing, gravure printing, letterpress printing, etc. with the scratch coloring ink used in the present invention. From the viewpoint of printability, it is particularly preferable to produce by offset printing. In the case of offset printing, it may be the same as the printing conditions using a normal offset printing ink, and either a method using a dampening liquid or a method using a waterless lithographic plate may be used. The printing amount of the scratch coloring ink is not particularly limited.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to this Example.

(Production example)
The following are preparation examples of varnish, each ink base, and scratch coloring ink.

(Production of varnish)
As a vegetable oil, 20 parts by mass of linseed oil, 50 parts by mass of rosin-modified phenolic resin (mass average molecular weight 60,000, acid value 20 mgKOH / g) and 20 parts by mass of spindle oil are mixed and heated at about 200 ° C. for about 1 hour to dissolve the resin. Then, 10 parts by weight of spindle oil and 1 part by weight of an aluminum chelating agent were added and heated at about 180 ° C. for about 1 hour to prepare a varnish.

(Preparation of Scratch Coloring Dye Precursor Ink Base (a))
50 parts by mass of the varnish, 30 parts by mass of 3-dibutylamino-6-methyl-7-anilinofluorane, and 5 parts by mass of spindle oil are kneaded with a three roll mill, and 10 parts by mass of the varnish and 10 parts by mass of spindle oil. Was added to prepare a dye precursor ink base (a) for scratch coloring.

(Preparation of Scratch Color Developer Ink Base (b))
Kneading 50 parts by mass of the varnish, 30 parts by mass of 4-hydroxy-4'-isopropoxydiphenylsulfone and 5 parts by mass of spindle oil with a three roll mill, and adding 10 parts by mass of the varnish and 10 parts by mass of spindle oil Thus, a color developer ink base (b) for scratch coloring was prepared.

(Preparation of scratch coloring ink)
The above two ink bases (a) and (b) are mixed at a mass ratio of 1: 2, respectively, and 0.2% by mass of the manganese naphthenate of the dryer is added to the total of the ink bases, followed by thorough homogenization. Thus, a scratch coloring ink was prepared.

(Printing condition 1)
The conditions for obtaining the invisible information printing sheet were determined under the following conditions.
Printing speed 150m / min
Supports Supports of Examples and Comparative Examples Humidifying liquid 5% by mass IPA-0.2% by mass SEVENSTAR (manufactured by Dainichi Seika Kogyo Co., Ltd.) Use printing plate HPF 0.24 mm (manufactured by Fujifilm)
Halftone line number, halftone dot angle, halftone dot shape (printing halftone dot ratio is 50%)
100 lines, 45 degrees, circular Scratch coloring ink pattern
Patterns described in Examples and Comparative Examples Ink film thickness 1.4 μm
Printing machine MVF-18D (Miyakoshi)

Example 1
(Preparation of coating support)
Using a pigment coating layer coating liquid (A) having the following composition, a roll coater is applied so that the coating amount is 0.5 g / m ^{2 in a} dry state on one surface of a high-quality paper having a basis weight of 80 g / m ^2. The coating was dried and super calendered to obtain a coated support. The smoother smoothness was adjusted to 85.0 kPa.
Composition of pigment coating layer coating solution (A) Kaolin clay (average particle size 1.5 μm) 30 parts by weight Light calcium carbonate (average particle size 1.8 μm) 70 parts by weight Phosphorylated starch 5 parts by weight Styrene / butadiene 10 parts by weight of latex (Pigment dispersion preparation, coating liquid preparation, and coating liquid concentration adjustment were in accordance with conventional methods.)
(Preparation of invisible information printed sheet)
Using the scratch coloring ink obtained in the above preparation example on the coating layer surface of the obtained coating support, 1-digit Chinese numerals (24 points) from 1 to 9 so that the ink film thickness becomes 0.6 μm. , Gothic.) And triangular, square, and round geometric patterns (triangles, squares, and circles are also printed with ink. For example, in the case of a circle, a black design can be seen by scratching when it is black) The invisible information print sheet was obtained by offset printing under the condition of 1. The smoothness smoothness of the invisible information printed sheet was 85.0 kPa, and no change was observed before printing.

(Example 2)
An invisible information printed sheet was obtained in the same manner as in Example 1 except that the coating amount of the pigment coating layer was changed to 1.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 80.0 kPa.

(Example 3)
An invisible information printed sheet was obtained in the same manner as in Example 1 except that the coating amount of the pigment coating layer was changed to 2.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 77.5 kPa.

Example 4
An invisible information printed sheet was obtained in the same manner as in Example 1 except that the coating amount of the pigment coating layer was changed to 3.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 18.0 kPa.

(Example 5)
An invisible information printed sheet was obtained in the same manner as in Example 1 except that the coating amount of the pigment coating layer was changed to 5.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 73.0 kPa.

(Example 6)
The invisible information printing sheet was prepared in the same manner as in Example 1 except that the roll coater used in Example 1 was changed to a blade coater and the coating amount of the pigment coating layer was changed to 6.0 g / m ² in a dry state. Obtained. The smoothing smoothness of the coating support was adjusted to 30.0 kPa.

(Example 7)
An invisible information printed sheet was obtained in the same manner as in Example 6 except that the coating amount of the pigment coating layer was changed to 6.5 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 23.0 kPa.

(Comparative Example 1)
An invisible information printed sheet was obtained in the same manner as in Example 1 except that the high-quality paper of the base material was used as it was as the support without providing the pigment coating layer in Example 1. The smooth paper smoothness of the high-quality paper as the support was 90.0 kPa.

(Comparative Example 2)
An invisible information printed sheet was obtained in the same manner as in Example 6 except that the coating amount of the pigment coating layer was changed to 7.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 18.0 kPa.

(Comparative Example 3)
An invisible information printed sheet was obtained in the same manner as in Example 6 except that the coating amount of the pigment coating layer was changed to 10.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 13.0 kPa.

(Comparative Example 4)
An invisible information printed sheet was obtained in the same manner as in Example 6 except that the coating amount of the pigment coating layer was changed to 13.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 11.0 kPa.

(Comparative Example 5)
An invisible information printed sheet was obtained in the same manner as in Example 6 except that the coating amount of the pigment coating layer was changed to 16.0 g / m ² in a dry state. The smooth smoothness of the coating support was adjusted to 5.5 kPa.

(Comparative Example 6)
An invisible information printed sheet was obtained in the same manner as in Example 6 except that the coating amount of the pigment coating layer was changed to 19.0 g / m ² in a dry state. The smoothing smoothness of the coating support was adjusted to 0.9 kPa.

(Examples 8 to 13)
An invisible information printed sheet was obtained in the same manner as in Example 5 except that the basis weight of the high-quality paper as the base material used in Example 5 was changed as follows. The fine paper basis weight as a base material of each Example is shown below. The smoothing smoothness of the coating support used in Examples 8 to 13 was adjusted to 10.5 kPa.
Example Substrate fine paper basis weight (g / m ² )
Example 8 60
Example 9 100
Example 10 120
Example 11 150
Example 12 180
Example 13 200

(Example 14)
The pigment coating layer coating solution (A) used in Example 5 was used as the pigment coating layer coating solution (B) having the following composition.
Kaolin clay (average particle size 1.5 μm) 30 parts by weight Light calcium carbonate (average particle size 1.8 μm) 70 parts by weight Phosphate esterified starch 1.7 parts by weight Styrene / butadiene latex 3.3 parts by weight Except for the above, an invisible information printed sheet was obtained in the same manner as in Example 5.

(Example 15)
The pigment coating layer coating solution (A) used in Example 5 was used as the pigment coating layer coating solution (C) having the following composition.
Kaolin clay (average particle size 1.5 μm) 30 parts by weight Light calcium carbonate (average particle size 1.8 μm) 70 parts by weight Phosphate esterified starch 3.4 parts by weight Styrene / butadiene latex 6.6 parts by weight Except for the above, an invisible information printed sheet was obtained in the same manner as in Example 5.

(Example 16)
The pigment coating layer coating liquid (A) used in Example 5 was used as the pigment coating layer coating liquid (D) having the following composition.
Kaolin clay (average particle size 1.5 μm) 30 parts by weight Light calcium carbonate (average particle size 1.8 μm) 70 parts by weight Phosphate-esterified starch 6.8 parts by weight Styrene / butadiene latex 13.2 parts by weight Except for the above, an invisible information printed sheet was obtained in the same manner as in Example 5.

(Example 17)
The pigment coating layer coating solution (A) used in Example 5 was used as the pigment coating layer coating solution (E) having the following composition.
Kaolin clay (average particle size 1.5 μm) 30 parts by weight Light calcium carbonate (average particle size 1.8 μm) 70 parts by weight Phosphate esterified starch 10 parts by weight Styrene / butadiene latex Except for changing to 20 parts by weight An invisible information printed sheet was obtained in the same manner as in Example 5.

(Example 18)
The pigment coating layer coating solution (A) used in Example 5 was used as the pigment coating layer coating solution (F) having the following composition.
Kaolin clay (average particle size: 1.5 μm) 15 parts by weight Calcined clay (average particle size: 1.5 μm) 15 parts by weight Light calcium carbonate (average particle size: 1.8 μm) 20 parts by weight Heavy calcium carbonate (average particle size: 1. 8 parts by weight Talc (average particle size 1.8 μm) 20 parts by weight Aluminum hydroxide (average particle diameter 1.0 μm) 10 parts by weight Phosphoric esterified starch 10 parts by weight Styrene / butadiene latex 20 parts by weight Except for the above, an invisible information printed sheet was obtained in the same manner as in Example 5.

(Example 19)
An invisible information printed sheet was obtained in the same manner as in Example 1 except that the coating support used in Example 1 was changed to the product name Pearl Soft manufactured by Mitsubishi Paper Industries Co., Ltd. In addition, the base material of this support body is a medium quality paper. The coating amount of the one-side terms are 5.0 g / ^{m 2,} the substrate basis weight was 117.9 g / ^{m 2.} The smoother smoothness of the surface used for printing was 73.6 kPa.

(Evaluation 1 Invisible evaluation of printed parts)
The printed portions of the invisible information printing sheets obtained in Examples 1 to 19 and Comparative Examples 1 to 6 were evaluated by visual observation in the following three stages.
○ can not read the information at all.
Δ indicates that the information cannot be read but the print portion exists.
X indicates information is visually recognized.
In addition, (circle) and (triangle | delta) are a thing of a practical use level.

(Evaluation 2: Readability evaluation of printed parts)
The printed portions of the invisible information printing sheets obtained in Examples 1 to 19 and Comparative Examples 1 to 6 were rubbed with nails, and readability was evaluated in the following three stages.
○ is easy to read information.
Δ indicates that the information can be read but is slightly unclear.
X indicates that information cannot be read.
In addition, (circle) and (triangle | delta) are a thing of a practical use level.

(Evaluation 3 Ink flow evaluation of invisible information printing sheet)
The printed portions of the invisible information printing sheets obtained in Examples 1 to 19 and Comparative Examples 1 to 6 and the surrounding unprinted portions were rubbed with 10 yen coins, and the following items were evaluated.
○: Colored ink did not flow around the information.
In Δ, colored ink flowed around the information, but there was no problem in reading the information.
×: Colored ink flowed around the information, and trouble in reading information was recognized.

(Evaluation 4 Gloss change evaluation of invisible information printed sheet)
The printed portions of the invisible information printing sheets obtained in Examples 1 to 19 and Comparative Examples 1 to 6 and the surrounding exposed portions of the support were rubbed with 10 yen coins, and the following items were evaluated.
○ was not noticeable because there was no change in gloss even when the exposed part of the support was rubbed.
In Δ, a change in gloss was observed when the exposed portion of the support was rubbed, but there was no problem in reading information.
In x, troubles in reading information were recognized due to the change in gloss when rubbing the exposed part of the support.

(Evaluation 5: Darkening evaluation of invisible information printed sheet)
The printed portions of the invisible information printing sheets obtained in Examples 1 to 19 and Comparative Examples 1 to 6 and the surrounding exposed portions of the support were rubbed with 10 yen coins, and the following items were evaluated.
○ was not noticeable even if the exposed part of the support was rubbed.
In Δ, darkening was observed when the exposed portion of the support was rubbed, but information reading was not hindered.
×: Obstacles in reading information due to darkening when the exposed part of the support was rubbed.
In all of the ink flow, gloss change, and darkening evaluation, ○ or Δ is a practical level. When any of the evaluations 3 to 5 is “x”, there is a problem in reading information.

(Evaluation 6: Scratch strength evaluation of invisible information printed sheet)
The printed portions of the invisible information printing sheets obtained in Examples 1 to 19 and Comparative Examples 1 to 6 and the surrounding exposed portions of the support were rubbed with 100 yen coins, and the following items were evaluated.
○: The sheet was not torn or the surface was not scratched even when rubbed strongly.
△: When the sheet was rubbed strongly, the sheet was partially torn or the surface was scratched, but there was no hindrance to reading.
×: When the sheet was rubbed strongly, the sheet was torn and the surface was crumpled. There is a problem in reading.
In each scratch strength evaluation, ○ or Δ is a practical level.

  The evaluation results are summarized in Table 1.

（注１） 塗工液(Ａ)、(Ｂ)、(Ｃ)、(Ｄ)、(Ｅ)、(Ｆ)の詳細は、それぞれ実施例
１、１４、１５、１６、１７、１８の本文を参照。
（注２） 実施例１、２、３および７は、補正により請求項１における顔料塗工層
の塗工量が３．０ｇ／ｍ ² 〜６．０ｇ／ｍ ² に限定されたことにより参考例である。

(Note 1 ) Details of coating liquids (A), (B), (C), (D), (E), and (F) are the texts of Examples 1, 14, 15, 16, 17, and 18, respectively. See
(Note 2) Examples 1, 2, 3 and 7 were corrected for the pigment coating layer according to claim 1
The amount of the coating is a reference example by being limited to ^{3.0g / m 2 ~6.0g / m 2} .

(Reference printing conditions)
Example 1 except that 24 points adopted in Example 1, 12 points instead of Gothic, and the reference printing conditions as Gothic were used on the supports used in Examples 1 to 19 and Comparative Examples 1 to 6, respectively. And printed in the same way. As a result, there was no difference in invisibility and visibility between each example and each comparative example.

(Reference Printing test with printing ink)
Except for using SCR SOY TF ink (manufactured by Toyo Ink Co., Ltd.) instead of scratch coloring ink as a commercially available black ink for offset printing on the supports used in Examples 1 to 19 and Comparative Examples 1 to 6. Printing was performed in the same manner as in printing condition 1 above. As a result, each of the examples using the coated support and Comparative Examples 2 to 6 have a better printing appearance than Comparative Example 1 using the fine paper as the support, and the appearance is better as the coating amount is larger. It was a trend.

  The invisible information printing sheet of the present invention can visualize invisible information without using a special tool (coin or the like), and has a good appearance. As an example of use, the child's hands are not soiled and no scraps are generated, so it is particularly effective for use in a vehicle or in a store that handles food and drink.

Claims (7)

In an invisible information printing sheet in which a printed part using a scratch coloring ink containing a dye precursor, an electron accepting developer and a varnish is provided on a support, the support is made of a scratch coloring ink. Coating support in which a pigment coating layer containing a pigment and a binder and having a coating amount of 3.0 g / m ² to 6.0 g / m ² is provided on the surface on which the printed portion used is provided An invisible information printing sheet characterized by being a body. The invisible information printing sheet according to claim 1, wherein in the pigment coating layer, the mass ratio of the pigment to the binder is 5 to 30 parts by mass of the binder with respect to 100 parts by mass of the pigment. The invisible information printing sheet according to claim 1 or 2 , wherein the pigment is at least one selected from kaolin clay, calcined clay, light calcium carbonate, heavy calcium carbonate, aluminum hydroxide, and talc. Mohs hardness of the pigment is 3.5 or less, the invisible information printed sheet according to any one of claims 1-3. The invisible information printing sheet according to any one of claims 1 to 4 , wherein the pigment has an average particle diameter of 0.02 to 5 µm. The invisible information printing sheet according to any one of claims 1 to 5 , wherein the smooth smoothness of the coating support is 1.0 to 85.0 kPa. The basis weight of the substrate for pigment coating is 40~450g / m ^2, the invisible information printed sheet according to any one of claims 1-6.