JPH04244894A - Transfer sheet for water color development recording - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer sheet provided with a recorded image made of a material that is invisible under normal conditions and develops color when water is attached to the sheet.

0002

[Prior Art] Conventionally, as a recording method that is normally invisible but becomes visible when necessary, pictures and letters are written on paper with squeezed tangerine juice, etc., and when it dries, it becomes difficult to see. If you burn it with fire, the pictures and letters will turn black and brown again, which is what is called broiling. However, this roasted product shows discoloration even before it is roasted.

On the other hand, there is a method in which the latent image of an ultraviolet absorber is visualized in a dark place under a fluorescent lamp, and a method in which the latent image of an electron-accepting color developer is visualized by spraying an organic solvent in which an electron-donating dye is dissolved. Although these methods have been proposed, there are problems such as the need for special location selection and the use of organic solvents for visualization.

0004

[Problems to be Solved by the Invention] The present invention provides water-colorable recording in which a recorded image appears simply by applying water without selecting a special location or using special equipment or chemicals. To provide a transfer sheet on which an image can be easily provided at low cost. As a result of research in order to solve such problems, the present inventors first deposited on a support,
Contains a colorless or light-colored basic dye, a water-chromic material consisting of a coloring agent, a desensitizer, and an adhesive that can develop color when in contact with the dye, and can be transferred from the substrate to the recording sheet by applying pressure or heating. A water-chromic recording transfer material and method provided with a transferring transfer layer was proposed (Japanese Patent Application No. 116490/1999).

However, as research progressed, it was discovered that if a porous base material like paper is used as a support for a transfer sheet and stored for a long period of time in a rolled state or in a stacked state after being cut, the winding of the roll will deteriorate. Depending on the pressure and load, a problem arose in that the transfer efficiency deteriorated.

[0006]

[Means for solving the problem] As a result of repeated research into the cause of this reduction in transfer efficiency, we found that if the transfer sheet is left under pressure, part of the transfer layer will migrate to the back side of the transfer sheet. It was found that the transfer layer became hard and the transfer efficiency deteriorated. The present inventors have discovered that by providing a transfer prevention layer on the non-transfer surface of the support, excellent storage stability and always good transferred images can be obtained.

[0007] The present invention provides a colorless to light-colored basic dye, a coloring agent capable of forming a color when it comes into contact with the dye, on one side of the support.
In a water-colorable recording transfer sheet containing a water-colorable material consisting of a desensitizer and an adhesive and provided with a transfer layer that is transferred to the recording sheet by pressure or heating, a transfer prevention layer is provided on the back side. This is a water-chromic recording transfer sheet characterized by:

[0008]

[Function] The present invention is characterized in that a transfer sheet for water color-forming recording is provided with a transfer prevention layer on the back side. The transfer prevention layer is preferably made of a film-forming substance, specifically starches such as grain starch, pregelatinized starch, oxidized starch, ether starch, and ester starch, gelatin, albumin, casein, etc. Proteins, celluloses such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, agar, sodium alginate, water-soluble natural polymer compounds such as polysaccharides such as gum arabic, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid,
Water-soluble synthetic polymer compounds such as polyacrylamide, maleic acid copolymer, etc.; styrene-butadiene copolymer latex, acrylic ester polymer latex,
Water-dispersible polymer compounds such as vinyl acetate polymer latex and vinyl chloride polymer are used.

[0009] A mold-releasing substance such as metal soap, silicone, wax emulsion, etc. can be added to this transfer-preventing layer for the purpose of improving the mold-releasing property and further increasing the transfer-preventing effect.

[0010] This layer can also be colored by containing an organic or inorganic colored compound. This is preferable because the transfer surface of the transfer sheet and the transfer prevention layer surface can be clearly distinguished. Examples of organic or inorganic colored compounds include acid dyes such as Methanyl Yellow, Orange II, Methyl Red, Acid Red, Victoria Violet, Acid Fuchsin, and Brilliant Blue; Naphthol AS, Fast Red TR, Fast Blue BB Salt, and α-naphthylamine. Azoic dyes such as rhodamine 6G, crystal violet, methylene blue, malachite green, facsimile basic, acridine yellow; pigment dyes such as permanent orange, deep red, phthalocyanine blue; cobalt green, cerulean blue, cobalt violet,
Examples include inorganic compounds such as barium chromate and cadmium red.

These materials are usually prepared as an aqueous dispersion into a coating solution, and coated on the back side of the support with a suitable well-known and commonly used coating device such as a bar coater, air knife coater, blade coater, curtain coater, etc. to prevent transfer. layers are provided. The coating amount is adjusted depending on the conditions such as the material forming the transfer layer and the method of forming the transfer prevention layer, but it is usually about 0.5 to 10 g/m2 in terms of dry weight, preferably 1 to 8 g/m2.
It is about m2. Incidentally, if the amount is less than 0.5 g/m2, the effect of preventing metastasis cannot be obtained, and if it is more than 10 g/m2, there is no cost advantage.

[0012] Examples of basic dyes used in water coloring materials include the following. 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide, 3
, 3-bis(p-dimethylaminophenyl)phthalide,
3-(p-dimethylaminophenyl)-3-(1,2-
dimethylindol-3-yl)phthalide, 3-(p-
dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, 3,3-bis(1,2-dimethylindol-3-yl)-5-dimethylaminophthalide, 3,3-bis( 1,2-dimethylindole-3
-yl)-6-dimethylaminophthalide, 3,3-bis(9-ethylcarbazol-3-yl)-6-dimethylaminophthalide, 3,3-bis(2-phenylindol-3-yl)- 6-dimethylaminophthalide, 3-p
-dimethylaminophenyl-3-(1-methylpyrrol-3-yl)-6-dimethylaminophthalide, 3-4-
(diethylamino)-2-ethoxyphenyl-3-(2
-Methyl-1-octyl-3-indolyl)-4-azaphthalide, 3,3-bis(2-methyl-1-octyl-
Triallylmethane dyes such as 3-indolyl) azaphthalide, 4,4'-bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl-leucoauramine, N-2,4,5-trichlorophenylleucoauramine, etc. diphenylmethane dyes, thiazine dyes such as benzoylleucomethylene blue and p-nitrobenzoylleucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-
Phenyl-spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho(6'-methoxybenzo)spiropyran, 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-methoxyfluoran, 3- diethylamino-6-methoxyfluorane, 3-diethylamino-7-methoxyfluorane,
3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-
Diethylamino-6,7-dimethylfluorane, 3-(
N-ethyl-p-toluidino)-7-methylfluorane, 3-diethylamino-7-(N-acetyl-N-methylamino)fluorane, 3-diethylamino-7-(N
-methylamino)fluoran, 3-diethylamino-7
-dibenzylaminofluorane, 3-diethylamino-
7-(N-methyl-N-benzylamino)fluoran,
3-diethylamino-7-(N-chloroethyl-N-methylamino)fluorane, 3-diethylamino-7-diethylaminofluorane, 3-(N-ethyl-p-toluidino)-6-methyl-7-phenylaminofluorane , 3-(N-ethyl-p-toluidino)-6-methyl-
7-(p-toluidino)fluoran, 3-diethylamino-6-methyl-7-phenylaminofluoran, 3-
Dibutylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-7-(2-carbomethoxyphenylamino)fluorane, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-phenyl Aminofluorane, 3-pyrrolidino-6-methyl-7-
Phenylaminofluorane, 3-piperidino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-(2,4-dimethylamino)fluorane, 3-diethylamino-7-(o-chlorophenyl amino) fluorane, 3-dibutylamino-7-(o
-chlorophenylamino)fluoran, 3-pyrrolidino-6-methyl-7-(p-butylphenylamino)fluoran, 3-(N-methyl-N-n-amylamino)-
6-Methyl-7-phenylaminofluorane, 3-(N
-ethyl-N-n-amylamino)-6-methyl-7-
Phenylaminofluorane, 3-(N-ethyl-N-isoamylamino)-6-methyl-7-phenylaminofluorane, 3-(N-methyl-N-n-hexylamino)-6-methyl-7- Phenylaminofluorane, 3-
(N-ethyl-N-n-hexylamino)-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-
Examples include fluoran dyes such as N-β-ethylhexylamino)-6-methyl-7-phenylaminofluoran. Of course, the dyes are not limited to these dyes, and two or more types of dyes can be used in combination.

[0013] As for the coloring agent used in combination with the above-mentioned basic dye, the following substances which are known in the fields of pressure-sensitive copying paper and heat-sensitive recording paper are exemplified. 4-te
rt-butylphenol, α-naphthol, β-naphthol, 4-acetylphenol, 4-tert-octylphenol, 4,4'-sec-butylidenephenol, 4-phenylphenol, 4,4'-dihydroxy-diphenylmethane, 4, 4'-isopropylidene diphenol, hydroquinone, 4,4'-cyclohexylidene diphenol, 4,4'-dihydroxydiphenyl sulfide, 4,4'-thiobis(6-tert-
butyl-3-methylphenol), 4,4'-dihydroxydiphenylsulfone, hydroquinone monobenzyl ether, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,2', 4,4'-tetrahydroxybenzophenone, dimethyl 4-hydroxyphthalate, methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, -sec-butyl 4-hydroxybenzoate, 4-hydroxy Pentyl benzoate, phenyl 4-hydroxybenzoate,
Benzyl 4-hydroxybenzoate, tolyl 4-hydroxybenzoate, chlorophenyl 4-hydroxybenzoate,
Phenylpropyl 4-hydroxybenzoate, phenethyl 4-hydroxybenzoate, p-4-hydroxybenzoate
Phenolic compounds such as chlorobenzyl, p-methoxybenzyl 4-hydroxybenzoate, novolax type phenolic resin, phenol polymer; benzoic acid, p-ter
t-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, 3-sec-butyl-4-hydroxybenzoic acid,
3-cyclohexyl-4-hydroxybenzoic acid, 3,5
-dimethyl-4-hydroxybenzoic acid, salicylic acid, 3
-isopropylsalicylic acid, 3-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3-(α-methylbenzyl)salicylic acid, 3-chloro-5-(α-methylbenzyl)salicylic acid, 3,5-di-tert-butylsalicylic acid , 3-phenyl-5-(α,α-dimethylbenzyl)salicylic acid, 3,5-di(α-methylbenzyl)
Aromatic carboxylic acids such as salicylic acid; organic acidic substances such as salts of these aromatic carboxylic acids and polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, and nickel. Of course, it is also possible to use two or more of these coloring agents in combination, if necessary.

The basic dye and coloring agent are appropriately selected and used so as to obtain the desired color. The mixing ratio of the basic dye and the coloring agent is preferably adjusted to about 50 to 600 parts by weight, preferably about 100 to 400 parts by weight, based on 100 parts by weight of the dye.

As the desensitizer, any known desensitizer can be used as long as it is easily soluble in water, specifically glycerin;
Dodecylamine; 2,4,4-trimethyl-2-oxazoline; N,N-di(polyoxyethylene)ethylamine; polyoxypropylene-diethylamine adduct; polyethyleneimine; polyethylene glycol, polypropylene glycol, ethylene glycol and propylene glycol Polyolefin glycols such as copolymers; Cationic surfactants such as dodecyl-trimethylammonium chloride and stearylamine acetate; Polyoxyethylene alkyl ether sodium sulfate, polyoxyethylene alkyl ether sulfate triethanolamine, polyoxyethylene alkylphenol ether sulfate Anionic surfactants such as sodium; nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene sorbitan monolaurate, polyethylene glycol monostearate, etc. etc.

Among these, polyethyleneimine,
Polyolefin glycols, anionic surfactants, and nonionic surfactants having an average molecular weight of about 300 to 2,000 are particularly excellent in decoloring properties and water coloring properties, and are therefore preferably used. Of course, two or more of these desensitizers can also be used in combination. The amount of the desensitizer to be used cannot be definitively stated depending on the type of support, basic dye, and coloring agent used, but it is 50 to 20 parts by weight per 100 parts by weight of the coloring agent.
It may be within a range of about 0.00 parts by weight.

[0017] When the adhesive is applied by coating, for example, starches such as grain starch, pregelatinized starch, oxidized starch, etherified starch, and esterified starch, gelatin, albumin, casein, etc. can be used as the adhesive. Proteins, celluloses such as carboxymethylcellulose and hydroxyethylcellulose, water-soluble natural polymer compounds such as agar, sodium alginate, polysaccharides such as gum arabic, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid,
Water-soluble synthetic polymer compounds such as polyacrylamide, maleic acid copolymer, etc.; styrene-butadiene copolymer latex, acrylic ester polymer latex,
Vinyl acetate polymer latex, vinyl chloride polymer,
Water-dispersible polymer compounds such as wax emulsions; semi-synthetic resins such as ethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, nitrocellulose, phenolic resins, xylene resins, urea resins, melamine resins , ketone resin, coumaron/indene resin, petroleum resin, terpene resin, cyclized rubber,
Chlorinated rubber, alkyd resin, polyamide resin, acrylic resin, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, polyvinyl acetate, polyvinyl butyral (butyral resin), polyvinylpyrrolidone, chlorinated polypropylene resin, epoxy resin, polyurethane, etc. Examples include synthetic resins.

On the other hand, when forming by a printing method, for example, when preparing a flexo type or gravure type ink composition, the above-mentioned materials can be used as the adhesive. Among them, polyvinyl acetate, vinyl chloride/vinyl acetate copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer Preferred are polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, ethyl cellulose, nitrocellulose, hydroxypropyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like.

[0019] Waxes are mainly used as adhesives for hot-melt inks. These waxes include animal waxes such as beeswax, spermaceti wax, and lanolin, vegetable waxes such as candelilla wax, carnauba wax, tree wax, rice wax, and sugarcane wax, and montan wax, ozokerite, and lignite wax. Mineral wax, paraffin wax, petroleum wax such as microcrystalline wax, modified wax such as montan wax derivative, paraffin wax derivative, microcrystalline wax derivative, hydrogenated wax such as castor wax, opal wax, low molecular weight polyethylene and its derivatives. , acrawax, synthetic waxes such as distearyl ketone, caproic acid amide, caprylic acid amide, pelargonic acid amide, capric acid amide, lauric acid amide, tridecylic acid amide, myristic acid amide, stearic acid amide, behenic acid amide, ethylene bis Fatty acid amide waxes such as stearic acid amide, caproleic acid amide, oleic acid amide, linoleic acid amide, ricinoleic acid amide, linolenic acid amide, fatty acid based waxes such as stearic acid and behenic acid, alcohol based waxes such as stearyl alcohol, Phosphate ester waxes such as stearyl phosphate ester can be used alone or in combination. These adhesives are used in an amount of 5 to 75% by weight, preferably 10 to 6% by weight based on the total solid content of the water-colorable material.
It is used in an amount of about 5% by weight.

Furthermore, the coating composition contains a sensitizer to improve color development sensitivity, an ultraviolet absorber and an antioxidant to impart aging resistance, and kaolin to impart whiteness. It is also possible to add inorganic pigments such as clay, talc, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, and silica-activated clay. Furthermore, a dispersant, preservative, antifoaming agent, fluorescent dye, etc. may be added as necessary.

[0021] These materials are usually prepared by dispersing the dye and/or coloring agent together or separately using water as a dispersion medium and using a stirring or pulverizing machine such as a ball mill, attritor, or sand mill. A coating liquid is prepared by emulsifying the coloring agent or further dissolving both in an organic solvent to form a coating liquid.

The method for forming the transfer layer is not particularly limited, and it can be formed according to conventionally well-known and commonly used techniques. For example, suitable coating devices such as a bar coater, air knife coater, blade coater, curtain coater, etc., and various printing machines such as letterpress, planographic, intaglio, flexo, gravure, screen, and hot melt printing can be used. Various printing machines can be used. Note that the order in which the transfer layer and the transfer prevention layer on the back surface are formed is not particularly limited.

The support that can be used in the present invention may be paper, synthetic paper, nonwoven fabric, woven fabric, film, or the like. In the case of a porous support, an undercoat layer such as a resin may be provided between the transfer layer and the support in order to improve transfer efficiency.

The water-chromic recording transfer sheet of the present invention is produced by stacking the transfer layer of the sheet and the recording sheet facing each other and applying pressure using a writing instrument such as a ballpoint pen, a typewriter, an impact printer, etc., or a thermal printer or the like. By heating, the transfer material in the area is transferred onto the recording sheet to form a water-colorable recorded image. The obtained water-colorable recorded image develops color simply by applying water, for example, by applying a water-containing brush or water spray, and can be identified as a colored printed image.

[0025] The mechanism by which a water-chromogenic recorded image develops color due to the adhesion of water has not been completely elucidated; however,
It is presumed that it is as follows. That is, when water is attached, the desensitizer present in the water-chromic recorded image is easily soluble in water,
When water adheres, the concentration is diluted and the ability to inhibit the coloring reaction between the basic dye and the coloring agent is reduced. As a result, a color reaction occurs between the dye and the coloring agent, and a visible image appears. If a large amount of water is applied, such as by using a water-containing brush or water spray, the dissolved desensitizer may penetrate into the base material of the recording sheet or diffuse to the periphery of the recorded image. It is thought that the proportion of the desensitizer in the visual image becomes small and the visible part irreversibly remains even after the water evaporates and dries.

On the other hand, if a small amount of water is applied, such as by blowing or exposing to water vapor, the penetration of the dissolved desensitizer into the base material or the diffusion to the periphery of the water-chromogenic recorded image is suppressed. As a result, the adhering water evaporates and decreases within the visibility coefficient of seconds to tens of seconds, and the desensitizer in the visible image is concentrated again, increasing its ability to inhibit the coloring reaction between the dye and the coloring agent. It will erase the color of the image. In other words, it is thought that the concentration of the desensitizer changes due to the adhesion and evaporation of water, and a reversible reaction occurs between the desensitizer and the dye, resulting in coloring and decoloring phenomena.

[0027]

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is of course not limited to these. Further, unless otherwise specified, parts and % in the examples indicate parts by weight and % by weight, respectively.

Example 1 3,3-bis(p-
30 parts of a 35% aqueous dispersion of dimethylaminophenyl)-6-dimethylaminophthalide, 55 parts of a 38% aqueous dispersion of zinc 3,5-di(α-methylbenzyl)salicylate micronized by a sand mill, 25 parts of 45% aqueous dispersion of micronized 1,2-bis(3-methylphenoxy)ethane, 80 parts of 48% styrene-butadiene copolymer latex, 60 parts of polyethylene glycol (average molecular weight: 1000), calcium carbonate. (Oil absorption: 95 ml/100 g) and 150 parts of water were mixed and stirred to prepare a water coloring material coating liquid.

On the other hand, a vinyl acetate-ethylene-vinyl chloride copolymer latex (manufactured by Sumitomo Chemical, Sumikaflex S-82) with a solid content of 50% was coated on one side of a 46 g/m2 base paper.
0) 140 parts, 80 parts of a 2.5% aqueous solution of sodium carboxymethylcellulose, 90 parts of a 30% aqueous dispersion of zinc stearate (Hydrin Z-7, manufactured by Chukyo Yushi Co., Ltd.), 8 parts of water
Apply a coating liquid consisting of 0 parts in advance with a wire bar, dry it,
After forming a coating layer with a solid content of 7 g/m2, a water coloring material coating liquid was applied to the surface with a wire bar so that the weight after drying was 7 g/m2, and the colorless water coloring material was transferred. Layers were provided.

Next, 1000 parts of vinyl acetate-ethylene-vinyl chloride copolymer latex (manufactured by Sumitomo Chemical, Sumikaflex S-850) with a solid content of 50% and a solid content of 38%
paraffin wax emulsion (manufactured by Toho Chemical Industry,
HYTEC B-5936) 240 parts, 480 parts of a 2.5% aqueous solution of sodium carboxymethyl cellulose,
1300 parts of water was mixed and stirred to obtain a coating liquid for forming a transfer prevention layer. This coating liquid was applied to the opposite side using a wire bar and dried to form a transfer prevention layer of 2.5 g/m 2 to obtain a transfer sheet for water color recording.

[0031] The obtained transfer sheets were placed one on top of the other so that the front and back sides faced each other, and a load of 40 g/cm2 was applied.
It was left at 0°C for 7 days. Next, stack the transfer layer surface and the high-quality paper facing each other, and print from the transfer prevention layer side of the transfer sheet using a ballpoint pen to form a latent image on the high-quality paper. When it was applied, the printed area developed a clear blue color.

Example 2 Vinyl acetate-ethylene copolymer was used instead of vinyl acetate-ethylene-vinyl chloride copolymer latex (manufactured by Sumitomo Chemical, Sumikaflex S-850) with a solid content of 50% in the transfer prevention layer forming liquid. A water-chromic recording transfer sheet was obtained in the same manner as in Example 1, except that latex (Sumitomo Chemical, Sumikaflex S-752) was used.

[0033] The obtained transfer sheets were placed one on top of the other so that the front and back sides faced each other, and a load of 40 g/cm2 was applied.
It was left at 0°C for 7 days. Next, stack the transfer layer surface and the high-quality paper facing each other, and print from the transfer prevention layer side of the transfer sheet using a ballpoint pen to form a latent image on the high-quality paper. When it was applied, the printed area developed a clear blue color.

Example 3 A water-colorable recording transfer sheet was obtained in the same manner as in Example 1, except that 1000 parts of an 8% aqueous solution of methylcellulose (manufactured by Shin-Etsu Chemical, 60SH-03) was used as the transfer prevention layer forming liquid. . The obtained transfer sheets were stacked so that the front and back sides faced each other, a load of 40 g/cm 2 was applied, and the sheets were left at 40° C. for 7 days. Next, stack the transfer layer surface and the high-quality paper facing each other, and print from the transfer prevention layer side of the transfer sheet using a ballpoint pen to form a latent image on the high-quality paper. When it was applied, the printed area developed a clear blue color.

Example 4 A water-colorable recording transfer sheet was obtained in the same manner as in Example 1, except that 1000 parts of a 10% aqueous solution of polyvinyl alcohol (Kuraray Poval 205, manufactured by Kuraray) was used as the transfer prevention layer forming liquid. . The obtained transfer sheets were stacked so that the front and back sides faced each other, a load of 40 g/cm 2 was applied, and the sheets were left at 40° C. for 7 days. Next, stack the transfer layer surface and the high-quality paper facing each other, and print from the transfer prevention layer side of the transfer sheet using a ballpoint pen to form a latent image on the high-quality paper. When it was applied, the printed area developed a clear blue color.

Comparative Example A water-chromic recording transfer sheet was obtained in the same manner as in Example 1, except that no transfer prevention layer was formed. The obtained transfer sheets were stacked so that the front and back sides were facing each other, and a 40g/cm2
When a load of 100 ml was applied and the sheet was left at 40° C. for 7 days, blocking occurred between the sheets. Layer the transfer layer surface and high-quality paper facing each other, print from the back side of the transfer sheet using a ballpoint pen to create a latent image on the high-quality paper, and then apply water to the latent image using a water-soaked tissue. , the printed area did not develop any color.

Example 5 Water coloring was carried out in the same manner as in Example 1, except that 10 parts of a 1% solution of Fukushin Basic (methanol:water = 3:7) was further added to the transfer prevention layer forming coating liquid of Example 1. A transfer sheet for sex recording was obtained. The obtained transfer sheets were stacked so that the front and back sides faced each other, and a load of 40 g/cm2 was applied.
It was left at 40°C for 7 days. Next, stack the transfer layer surface and the high-quality paper facing each other, and print from the transfer prevention layer side of the transfer sheet using a ballpoint pen to form a latent image on the high-quality paper. When it was applied, the printed area developed a clear blue color. In addition, since the transfer layer is colorless and the transfer prevention layer is red, it is extremely practical as it prevents the front and back sides from being used incorrectly.

[0038]

[Effects of the Invention] As described above, it was confirmed that the water color-forming transfer sheet according to the present invention is excellent. The present invention can create a water-chromic recorded image by transferring the water-chromic material to another base material by applying pressure or heating, so it is widely used in typewriters, impact printers, thermal printers, etc. in addition to writing. It can be recorded with inexpensive OA equipment. In addition, the obtained water-chromic recorded image is normally invisible and information can be obtained simply by adding water, so it can be used in a wide range of practical applications such as the creation of secret documents and secret postcards.

Claims (1)

[Claims] 1. One side of the support contains a water color-forming material consisting of a colorless to light-colored basic dye, a coloring agent capable of forming a color upon contact with the dye, a desensitizer, and an adhesive, and 1. A water-colorable recording transfer sheet provided with a transfer layer that is transferred to a recording sheet by pressure or heating, characterized in that the water-colorable recording transfer sheet is provided with a transfer prevention layer on the back side.