JPH089259B2 - Tamper-proof pressure-sensitive copy sheet - Google Patents

Description

The present invention relates to a pressure-sensitive copy sheet, and more particularly to a tamper-proof pressure-sensitive copy sheet that cannot be tampered with by additional writing.

(Prior Art) Combination of electron-donating color former such as crystal violet lactone and benzoyl leuco methylene blue with electron-accepting developer such as activated clay, phenol-formaldehyde condensate and polyvalent metal salt of aromatic carboxylic acid (Leuco recording material), or nickel carboxylate and N,
Two types of chromogenic substances such as N'-di-benzyl-di-thio-oxide, a combination of a metal salt of an organic iron phosphate and stearyl gallate and a ligand compound (chelate recording material) are used. Pressure-sensitive copying sheets utilizing color reaction are well known.

Generally, such a pressure-sensitive copying sheet is prepared by applying a chromogen substance-containing microcapsule prepared by a method such as a phase separation method, an interfacial polymerization method, an in-situ method, etc. Lower paper (receiving sheet) with the other chromogen substance that develops color when it reacts with the chromogen substance
The above-mentioned microcapsules and a chromogen substance are applied to different surfaces of a support, and an intermediate paper is appropriately combined for practical use.

There is also a so-called self-coloring type pressure-sensitive copying sheet in which the above-mentioned microcapsules and a chromogen substance are laminated or mixed on the same surface of a support, and the back surface of the self-coloring type pressure-sensitive copying sheet is further provided. There is a self-coloring type pressure-sensitive copying sheet set in which a microcapsule layer is provided in the above and the above lower paper and middle paper are appropriately combined.

However, while these pressure-sensitive copy sheets are convenient in that they can be easily copied, they are additionally written using writing instruments, other pressure-sensitive copy paper of the same color, eraser, correction ink, knife, etc.
Alternatively, since it can be easily tampered with by means such as erasing, there is a problem that various troubles occur depending on the application.

Conventionally, as a pressure-sensitive copy paper having a tampering prevention function,
The back surface of upper paper, middle paper, or the like, that is, the microcapsule coating layer (5) containing the chromogen substance, is thinly laminated with the other chromogen substance-containing layer (6) to make the back face a self-coloring type. There are some (Fig. 2). As a result, when writing on the front surface of the upper paper, the tamper-proof record (8) is formed on the back surface of the upper paper together with the receiving layer (7) by writing pressure, so that even if the characters written on the front surface are erased and rewritten. The back side cannot be rewritten and tampering can be prevented.

However, this type of pressure-sensitive copying paper is completely ineffective against tampering by the writing means, and has a drawback that the back surface of the upper paper is colored due to the pressure caused by the handling of the sheet and is easily soiled.

(Problems to be Solved by the Invention) An object of the present invention is to provide a tamper-proof pressure-sensitive copy sheet which cannot be tampered with by additional entry and in which color stains on the back surface do not occur during handling.

(Means for Solving the Problems) In the present invention, a transfer sheet (1) having microcapsules containing chromogen substances and a receiving sheet (2) that develops color by reacting with the chromogen substances in the microcapsules are combined. A pressure-sensitive copy sheet constituted by a receiving sheet (2)
However, a pigment coating layer (3) is provided on a support, and a dispersion system of the other chromogen substance which reacts with the chromogen substance of the transfer sheet (1) to form a color on the pigment coating layer (3). A transfer sheet is provided with a receiving layer (4) formed by printing or applying an ink or a dispersion type coating liquid, and a part of the receiving layer (4) is transferred to the back surface of the facing transfer sheet (1) by a recording pressure to transfer the transfer sheet. (1)
A tamper-proof pressure-sensitive copying sheet having a tamper-proof record on the back side.

(Operation) FIG. 1 is a cross-sectional view illustrating the tampering prevention pressure-sensitive copy sheet of the present invention. When writing on the surface of the transfer sheet (1) with a ballpoint pen (9) or the like, the chromogenic substance in the microcapsules is transferred from the transfer sheet (1) to the receiving layer (4) by the writing pressure.
To obtain a copy on the receiving layer (4).

In the present invention, the receptive layer (4) is formed by printing or applying a dispersion ink or a dispersion coating liquid of the other chromogen substance which causes a color reaction with the chromogen substance of the transfer sheet (1). To do. The other chromogenic substance of the dispersion type is less likely to penetrate into the pigment coating layer (3) than the dissolution type, and the chromogenic substance is likely to remain on the surface. Therefore, a part of the receiving layer (4) formed of the dispersion type ink or the dispersion type coating liquid is easily peeled off by the writing pressure and transferred to the back surface of the transfer sheet (1) facing it. As a result, the tamperproof recording (10) can be obtained on the back surface of the transfer sheet (1).

Since the transfer sheet (1) is stored separately from the receiving sheet (2) after writing, even if additional writing is performed on the front surface of the transfer sheet (1) for the purpose of falsification, it is not possible to additionally write up to the recording on the back surface. Therefore, it is possible to prevent falsification due to additional entry. In addition, the transfer sheet (1) does not cause coloring stain on the back surface during handling.

It is conventionally known to form a receiving layer on a support such as high-quality paper by printing or coating. However, a part of the receiving layer has never been configured to transfer to the back surface of the transfer sheet, and therefore the receiving layer has never been used for tampering prevention.

Examples of the combination of chromogenic substances used in the present invention include a combination of an electron-donating color former and an electron-accepting developer, or a combination of a metal salt and a ligand compound. Usually, the chromogenic substance contained in the microcapsules of the transfer sheet (1) is an electron-donating color former or a ligand compound, and the other chromogenic substance used in the receiving layer (4) is an electron-accepting substance. Colorant or metal salt.

As the electron-donating color former, the following substances known in the field of pressure-sensitive copying paper can be exemplified.

3,3-Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl)
Phthalide, 3,3-bis (1,2-dimethylindole-3-
Yl) -5-dimethylaminophthalide, 3,3-bis (9
-Ethylcarbazol-3-yl) -6-dimethylaminophthalide, triallylmethane dyes, 4,4'-bis-dimethylaminobenzhydrylbenzyl ether,
Diphenylmethane dyes such as N-halophenyl-leuco auramine and N-2,4,5-trichlorophenyl leuco auramine, thiazine dyes such as benzoyl leuco methylene blue and p-nitrobenzoyl leuco methylene blue, 3-methyl-spiro-dinaphthopyran , 3-phenyl-spiro-dinaphthopyran, 3-propyl-spiro-
Spiro dyes such as dibenzopyran, lactam dyes such as rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) lactam, rhodamine (o-chloroanilino) lactam, 3-dimethylamino-7-methoxyfluorane, 3- Diethylamino-6-methyl-7-chlorofluorane, 3- (N-ethyl-p-toluidino)
-7-Methylfluorane, 3-dimethylamino-7-N
-Methylaminofluorane, 3-diethylamino-7-
Dibenzylaminofluorane, 3- (N-ethyl-p-
Toluidino) -6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-phenylaminofluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-phenylamino Fluoran, 3-piperidino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-
Fluoran-based dyes such as xylidinofluorane and mixtures thereof.

Examples of the electron-accepting color developing agent include the following substances known in the field of pressure-sensitive copying paper.

Clays such as acid clay, activated clay, attapulgite, zeolite, bentonite, phenolic resin,
Polyvalent metal salts of various aromatic carboxylic acids as described in JP-B-51-25174, 2,2 'as described in JP-A-54-106316
-Organic developers such as zinc salts of bisphenol sulfone compounds and mixtures thereof.

Examples of the combination of the metal salt and the ligand compound include the following combinations of substances known in the field of pressure-sensitive copying paper.

Nickel stearate and N, N'-di-benzyl-di-
Thio-oxamide, nickel laurate and α-benzyl glyoxime, tricaprylmethyl ammonium vanadate and dodecyl amine 8-hydroxyquinoline sulfonate, benzyl lauryl dimethyl ammonium molybdate and lauryl protocatechuate, titanium stearate and lauryl gallate, Iron naphthenate and benzyl gallate, polyferrophenylmethylsiloxane and methylenebis (8-oxyquinoline), copper palmitate and N, N'-
Bis-2-octanoyloxyethyldiethyldithiooxamide, cobalt laurate and di-o-tolylguanidine, hinokitiol and polyvanadophenylmethylsiloxane, organic iron phosphates and gallic acid described in JP-A-58-38191 Combinations such as lauryl acid and mixtures thereof.

The pigment coating layer (3) used in the receiving sheet (2) in the present invention prevents the ink of the receiving layer (4) from penetrating into the ink or the liquid support and, as a result, an excellent color image on the receiving layer. Is to give. The pigment coating layer (3) is a pigment,
A binder is further formed by applying an aqueous coating solution containing a dispersant, a colored dye, a fluorescent whitening agent, an ultraviolet absorber, an antioxidant, an antifoaming agent and the like, if necessary, to the support.

When the pigment coating layer (3) contains oil-containing microcapsules, the transfer of the receiving layer (4) is further promoted to form an extremely clear color image on the back surface of the transfer sheet (1) and to prevent alteration. It is a preferred embodiment of the present invention because it can be used for prevention. Microcapsules and oil will be described later.

As the pigment, aluminum, zinc, magnesium,
Calcium, oxides such as titanium, hydroxides, carbonates, sulfates, halides, and colloidal silica, zeolites, bentonite, kaolin, clays such as calcined kaolin, melamine resins, organic pigments such as urea resins and the like. To be

Examples of the binder used when preparing the aqueous coating solution include a water-soluble binder and a latex binder, and the water-soluble binder includes gelatin, albumin, proteins such as casein, cereal starch, pregelatinized starch,
Starches such as oxidized starch, etherified starch and esterified starch, celluloses such as carboxymethyl cellulose and hydroxyethyl cellulose, agar, sodium alginate,
Water-soluble natural polymer compounds such as polysaccharides such as arabic gum, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, there are water-soluble synthetic polymer compounds such as maleic acid copolymers, and as a latex binder, Styrene-butadiene latex, acrylonitrile-butadiene latex, acrylic ester latex, vinyl acetate latex,
Methyl methacrylate-butadiene latex and carboxy-modified (for example, acrylic acid) latex thereof and the like.

If the surface strength of the pigment coating layer (3) is weak, it is not possible to obtain an excellent printability when printing a ruled line or the like. Therefore, the binder in the coating liquid forming the pigment coating layer is usually contained in an amount of 10% by weight or more, more preferably 20% by weight or more, based on the total solid content.

The coating amount of the pigment coating layer (3) is not limited to this, but it is 1 to 15 g / m ^{2 in} terms of color development and economy.
Is preferable, and more preferably 3 to 10 g / m ² .

When the pigment coating layer (3) contains the other chromogenic substance that reacts with the chromogenic substance contained in the microcapsules of the transfer sheet (1) to produce a color, the pigment coating layer (3) will be exposed. It is possible to further improve the density of the color image formed in and the durability thereof.

The receiving layer (4) of the present invention is formed by printing or applying an aqueous or non-aqueous ink or coating liquid on the pigment coating layer (3).

The non-aqueous ink or coating liquid that forms the receiving layer (4) is used in addition to the other chromogenic substance that causes a color reaction with the chromogenic substance on the transfer sheet side and the non-aqueous medium, and if necessary, a binder, a pigment, UV absorber, antioxidant, fluorescent dye, colored dye, photopolymerization initiator, wax, dryer, thickener,
Various auxiliaries known in the ink field such as gelling agents are converted to evaporative drying type, radiation curing type and curing polymerization type inks.

In the case of an aqueous system, a binder, a pigment, an ultraviolet absorber, a fluorescent dye, a dispersant, etc. are added, if necessary, in addition to the chromogenic substance and water.

When a leuco recording material is used as the chromogenic substance, an electron-accepting developer is usually used in the receiving layer (4), but when an organic developer is used, the print storability is particularly excellent and a good tampering prevention function is obtained. Is obtained.

As the non-aqueous medium used when preparing the non-aqueous ink or coating liquid, those known in the printing industry can be appropriately used, but specific examples include benzene, toluene,
Xylene, cyclohexane, hexane, ligroin, methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, n-hexonol, cyclohexanol, 2-ethylhexyl alcohol, polyethylene glycol diacrylate,
Propylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, hexanediol diacrylate, 1,2-butanediol diacrylate, reaction product of epoxy resin and acrylic acid , Reaction product of methacrylic acid, pentaerythritol and acrylic acid, condensate of maleic acid and diethylene glycol and acrylic acid, methyl methacrylate, butyl methacrylate, styrene, vegetable oil (dry oil such as linseed oil and sunflower oil, soybean oil, etc. Semi-drying oil, non-drying oil such as castor oil), processing oil (dehydrated castor oil, polymerized oil, maleated oil,
Vinylated oils, urethane oils), mineral oils (machine oils, spindle oils) and the like.

Among these media, it is preferable to use one that does not easily dissolve the chromogenic substance in order to prepare the dispersion ink or the dispersion coating liquid.

In the present invention, it is extremely important that a part of the receiving layer (4) is transferred to the transfer sheet (1) by pressure.
For that purpose, the chromogen substance is contained in the ink or the coating liquid in a dispersed state, not in a dissolved state. That is, it is necessary to form the receiving layer (4) by printing or applying a dispersion ink or a dispersion coating liquid. The dissolved chromogenic substance easily penetrates into the pigment coating layer (3), and the formed receiving layer is extremely difficult to transfer to the back surface of the transfer sheet (1), so that the tampering prevention effect cannot be sufficiently obtained. Therefore, the chromogen substance may be partially dissolved in the medium of the ink or the coating liquid, but it is desirable that the chromogen substance in a dispersed state is contained in an amount of about 3% by weight or more based on the medium. .

As the binder used in the receiving layer ink or the coating liquid, rosin (gum rosin,
Wood rosin, tall oil rosin), shellac, natural resin such as copal, dalman, gilsonite, zein, hardened rosin, ester gum and other rosin esters, maleic acid resin, fumaric acid resin, duplex rosin, polymerized rosin, rosin-modified phenol resin , Methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, nitrocellulose and other semi-synthetic resins, phenol resins, xylene resins, urea resins melamine resins, Kent resins, coumarone indene resins , Petroleum resin, terpene resin, cyclized rubber, chlorinated rubber, alkyd resin, polyamide resin, acrylic resin, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polyvinyl acetate Le, polyvinyl butyral (butyral resin), polyvinyl pyrrolidone, chlorinated polypropylene styrene resins, epoxy resins, synthetic resins such as polyurethane.

These binders are selected and used according to the type of medium used and the like. Regarding the usage method, for example, the method disclosed in "Printing Ink Technology", CMC Corp., etc. can be appropriately adopted. Examples of the pigment include those described above.

The dispersion ink or coating liquid is usually water or a non-aqueous medium.
It is prepared by mixing 5 to 100 parts by weight of the chromogenic substance with 100 parts by weight, or further dispersing with a ball mill, sand grinder or the like and mixing other components. In the present invention, in order to improve the transferability and printing workability of the receiving layer (4), it is important to set the surface strength of the receiving layer (4) to be weaker than that of the pigment coating layer (3). Therefore, the binder is usually added in the range of 0.1 to 30% by weight, preferably 1 to 10% by weight of the total solid content of the receiving layer (4).

The amount of ink or coating liquid applied is not limited to this, but it is 0.
^{1g / m 2 ~10g / m 2} , more preferably from ^{0.3g / m 2 ~5g / m 2} .

Next, the transfer sheet (1) is obtained by coating a support with a microcapsule dispersion coating liquid containing an oil containing a chromogen substance. In addition to the microcapsules, a binder, a capsule protective material, a surfactant, an antifoaming agent, a pigment, a preservative, an ultraviolet absorber, an antioxidant and the like can be added to this dispersion liquid, if necessary. The coating amount on the support is not particularly limited, but preferably 1 to 10 g / m ² ,
It is more preferably ² to 7 g / m ² .

The microcapsules used in the present invention are conventionally known coacervation methods (for example, US Pat. No. 2800457,
No. 2800458, etc.) Interfacial polymerization method (for example, Japanese Patent Publication No. 38-19574, Japanese Patent Publication No. 42-446, Japanese Patent Publication No. 42-
771, No. 49-45133, etc.), in-si
tu polymerization method (eg Japanese Patent Publication No. 36-9168, Japanese Patent Publication No. 51-9079)
And the method disclosed in JP-B No. 53-84881).

Examples of the oil used in the present invention include the following substances known in the field of pressure-sensitive copying paper.

Vegetable oil such as cottonseed oil, kerosene, paraffin, naphthene oil, mineral oil such as chlorinated paraffin, alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylethane, triarylmethane, aromatic carbonization such as diphenylalkane Hydrogen, oleyl alcohol, tridecyl alcohol, benzyl alcohol, 1
-Alcohols such as phenylethyl alcohol and glycerin, organic acids such as oleic acid, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate,
Esters such as dioctyl phthalate, diethyl adipate, propyl adipate, di-n-butyl adipate, dioctyl adipate, organic phosphorus compounds such as tricresyl phosphate, tributyl phosphate, tributyl phosphite, tributyl phosphine oxide, phenyl cellosolve , Benzyl carbitol, polypropylene glycol, ethers such as propylene glycol monophenyl ether, amides such as N, N-dimethyllauramide, N, N-dimethylstearamide, N, N-dihexyloctylamide, diisobutyl ketone,
Ketones such as methylhexyl ketone, alkylene carbonates such as ethylene carbonate and propylene carbonate, and mixtures thereof.

In the present invention, the microcapsule coating liquid of the transfer sheet (1) and the pigment coating layer (3) of the receiving sheet are usually formed by methods such as air knife coating, roll coating and blade coating. Receiving layer (4)
When it is formed on the entire surface of the receiving sheet, it is similarly formed by the above coating method.

When the receiving layer (4) is locally formed, usually letterpress printing, intaglio (gravure) printing, planographic (offset) printing,
Printing methods such as screen printing are used, and in particular, local printing in the form of a non-aqueous ink is preferable for the purpose of printing work and tampering prevention, and a copy sheet that is good for flexographic printing using alcohol-based ink It is preferable because it can be obtained.

As the support used in the present invention, paper, synthetic fiber paper,
Examples thereof include synthetic resin films.

(Examples) In order to further clarify the effects of the present invention, examples and comparative examples will be given below, but the present invention is not limited to these examples. Parts and% in the examples represent parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 Preparation of Transfer Sheet (Upper Paper) 105 parts of internal phase oil obtained by heating and dissolving 5 parts of crystal violet lactone in 100 parts of diisopropyl naphthalene was added to aromatic polyisocyanate (trade name: Coronate-L, manufactured by Nippon Polyurethane Company) ) Dissolve 15 parts, add this to 600 parts of a 2% aqueous solution of polyvinyl alcohol and emulsify to obtain an average particle size.
After adjusting to 8.0 μ, this system was reacted at 80 ° C. for 4 hours to obtain a capsule dispersion liquid. Add 50 parts of starch particles and 20 parts of carboxy-modified styrene-butadiene copolymer latex to this dispersion.
Parts (solid content) were added and diluted to a concentration of 18% to prepare a microcapsule coating liquid.

The obtained capsule coating liquid was smeared on a base paper of 40 g / m ^{2 with} an air knife coater so that the solid content was 3.0 g / m ² , to obtain an upper paper.

Preparation of dispersion type developer ink for receiving layer 100 parts of 3,5-di- (tert-butyl) salicylate zinc, 5 parts of ethyl cellulose (ethyl cellulose No. 14, manufactured by Hercules), 360 parts of ethanol, 40 parts of n-hexyl alcohol Then, 40 parts of water was crushed by a ball mill to obtain a color developing ink. About 15% by weight of zinc 3,5-di- (tert-butyl) salicylate was dispersed in the medium.

Formation of pigment coating layer 3 parts (solid content) of sodium polyacrylate, 300 parts of light calcium carbonate were added to 900 parts of water, and 75 parts (solid content) of carboxy-modified styrene-butadiene copolymer latex was added to a dispersion liquid. was added dry weight base paper of 40 g / m ² was a coating solution prepared was spread by an air knife coater so that the 5 g / m ^2.

Preparation of Receiving Sheet (Lower Paper) The dispersion type developer ink was partially printed on the pigment coating layer by flexographic printing to obtain a printed matter having an ink amount of 1.5 g / m ² .

Evaluation When the transfer sheet (upper sheet) and the receiving sheet (lower sheet) were overlaid and printed with a typewriter, a blue colored image was obtained on the receiving layer printed portion of the receiving sheet and the back surface of the transfer sheet.

Example 2 Preparation of oil-containing microcapsule dispersion for pigment coating layer Ethylene-maleic anhydride copolymer (trade name EMA-31,
After emulsifying 100 parts of alkyldiphenylethane (trade name Hisol SAS-296, manufactured by Nippon Petrochemical Co., Ltd.) in a liquid having a pH of 6.0 by adding 20% caustic soda aqueous solution to 200 parts of 3.0% aqueous solution of Monsanto Co., The system was heated to 55 ° C.

Separately, 10 parts of melamine was added to 30 parts of 37% aqueous formaldehyde solution and reacted at 60 ° C. for 15 minutes to prepare an aqueous prepolymer solution.

This prepolymer aqueous solution was added dropwise to the emulsion, and 0.1N hydrochloric acid was added dropwise with stirring to adjust the pH to 5.3.
Warm up to 0 ℃, hold at that temperature for 1 hour, lower the pH to 4.0 with 0.2N-hydrochloric acid, hold for 3 hours, and allow to cool to obtain oil-encapsulated microcapsule dispersion with an average particle size of 4.0μ. Obtained.

Preparation of oil-encapsulated microcapsule-containing pigment coating layer The above oil capsule dispersion was added to a coating liquid prepared in the same manner as the coating liquid used for forming the pigment coating layer of Example 1,
Furthermore, 60 parts of starch particles and 20 parts (solid content) of carboxy-modified styrene-butadiene copolymer latex were added to prepare a coating solution, and 40 g / m ² of base paper was coated with an air knife coater to a dry weight of 5 g / m ^2. Smeared with.

Preparation of Receiving Sheet (Lower Paper) Dispersion type developer ink prepared in the same manner as in Example 1 was partially printed on the pigment coating layer by flexographic printing to obtain a printed matter having an ink amount of 1.5 g / m ² . .

Evaluation Transfer sheet (upper sheet) prepared in the same manner as in Example 1
When the above receiving sheet (lower paper) was overlaid and printed with a typewriter, a blue colored image was obtained on the receiving layer printed portion of the receiving sheet and the back surface of the transfer sheet. It was found that the color development on the back surface of the transfer sheet was better than that of Example 1.

Example 3 Preparation of pigment coating layer containing color developer 195 parts of light calcium carbonate, 60 parts of zinc oxide, 3,5-di-
Mixture of zinc (α-methylbenzyl) salicylate and α-methylstyrene / styrene copolymer (mixing / melting ratio 80/20) 4
To a dispersion obtained by pulverizing 5 parts, polyvinyl alcohol aqueous solution 15 parts (solid content) and water 900 parts with a ball mill for 24 hours,
Carboxy-modified styrene-butadiene copolymer latex 60 parts of an air knife coater so that the dry weight (solids) of the developer containing pigment coating solution was prepared by adding base paper 40 g / m ² is 5 g / m ² Smeared

Preparation of Receiving Sheet (Lower Paper) Dispersion type developer ink prepared in the same manner as in Example 1 was partially printed on the pigment coating layer by flexographic printing to obtain a printed matter having an ink amount of 1.5 g / m ² . .

Evaluation Transfer sheet (upper sheet) prepared in the same manner as in Example 1
When the above receiving sheet (lower paper) was overlaid and printed with a typewriter, a blue colored image was obtained on the receiving layer printed portion of the receiving sheet and the back surface of the transfer sheet. The color development on the receptor layer was found to be better than that of Example 1.

Example 4 Preparation of Pigment Coating Layer Containing Oil-Encapsulated Microcapsules and Developer A dispersion liquid prepared in the same manner as the coating liquid used for forming the developer-containing pigment coating layer of Example 3 was used as Example 2 A coating solution prepared by adding the oil-encapsulated microcapsule dispersion prepared in the same manner and further adding 60 parts of starch particles and 20 parts of carboxy-modified styrene-butadiene copolymer latex (solid content).
A 40 g / m ² base paper was smeared with an air knife coater so that the dry weight was 5 g / m ² .

Preparation of Receiving Sheet (Lower Paper) Dispersion type developer ink prepared in the same manner as in Example 1 was partially printed on the pigment coating layer by flexographic printing to obtain a printed matter having an ink amount of 1.5 g / m ² . .

Evaluation Transfer sheet (upper sheet) prepared in the same manner as in Example 1
When the above receiving sheet (lower sheet) was overlaid and printed with a typewriter, a clear blue color image was obtained on the back surfaces of the receiving sheet (lower sheet) and transfer sheet (upper sheet). The color development on the receiving layer and the color development on the back surface of the transfer sheet are both in Example 1.
It turned out to be better than that.

Comparative Example 1 As a result of evaluation in the same manner as in Example 3 except that a receptor sheet not printed on the developer-containing pigment coating layer prepared in the same manner as in Example 3 was used as the receptor sheet, No colored image was produced at all, and no tampering prevention function was obtained.

Comparative Example 2 A pigment-coated sheet containing oil-encapsulated microcapsules and a developer prepared in the same manner as in Example 4 as a receiving sheet was evaluated in the same manner as in Example 4 except that the receiving layer was used without printing. As a result, no color image was formed on the back surface of the transfer sheet, and the tampering prevention function could not be obtained.

(Effect) The present invention is an excellent tamper-proof pressure-sensitive copy sheet that cannot be tampered with by additional entry.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a tamperproof pressure-sensitive copy sheet of the present invention. FIG. 2 is a sectional view showing the structure of a conventional tamper-proof pressure-sensitive copy sheet. (1) …… Transfer sheet, (2) …… Receptor sheet (3) …… Pigment coating layer, (4) …… Receptor layer (5) …… Microcapsule coating layer (6) …… Other color source Body substance containing layer (7) …… Receptive layer, (8) …… Falsification prevention record (9) …… Ball pen, (10) …… Falsification prevention record

Claims (3)

[Claims] 1. A pressure-sensitive copying sheet comprising a transfer sheet (1) having microcapsules containing a chromogen substance and a receiving sheet (2) which reacts with a chromogen substance in the microcapsules to develop a color. At the receiving sheet (2)
However, a pigment coating layer (3) is provided on a support, and a dispersion system of the other chromogen substance which reacts with the chromogen substance of the transfer sheet (1) to form a color on the pigment coating layer (3). A transfer sheet (1) is provided with a receiving layer (4) formed by printing or applying an ink or a dispersion type coating liquid, and a part of the receiving layer (4) is transferred to the opposite back surface of the transfer sheet (1) by a recording pressure to transfer the transfer sheet. (1)
A tamper-proof pressure-sensitive copy sheet having a tamper-proof record on the back side. 2. The tamperproof pressure-sensitive copying sheet according to claim 1, wherein the pigment coating layer (3) of the receiving sheet (2) contains oil-containing microcapsules. 3. The pigment coating layer (3) of the receiving sheet (2) comprises:
The tamper-proof pressure-sensitive copy sheet according to claim 1, further comprising another chromogenic substance that develops color by reacting with the chromogenic substance contained in the microcapsules of the transfer sheet (1).