JPH05116470A - Label for multi-color thermal recording - Google Patents

Abstract

PURPOSE:To obtain a label for a multi-color thermal recording with which at least three-color recording is possible by providing at least three-layer thermal recording layer on one face of a supporting body and providing successively at least an adhesive layer and a release sheet on another face. CONSTITUTION:At least three-layer thermal recording layers 2, 1 and 6 (e.g. a cyan color developing layer 2, a mazenta color developing layer 1 and a yellow color developing layer 6) are provided on one face of a supporting body 3 consisting of a polyester film, etc., and at least an adhesive layer 4 and a release sheet 5 are successively provided on another face. As a result, it is possible to obtain a label for a multi-color thermal recording with which at least three-color recording is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording label, and more particularly to a multicolor heat-sensitive recording label capable of forming images of three or more colors.

[0002]

2. Description of the Related Art In a thermal recording method, (1) development is unnecessary, (2) when the support is paper, the paper quality is close to that of ordinary paper,
(3) Easy to handle, (4) High color density,
(5) The recording device is simple and inexpensive, and (6) it has no noise at the time of recording, so its application is expanded not only to the field of monochrome facsimiles and printers but also to the label field of POS and the like. ing. In such fields of POS as well, with the rapid development of the information industry, it is possible to easily obtain a color hard copy from a terminal of an information device such as a computer or a facsimile, and use it as a multi-color recording label for a product or There is an increasing demand for affixing to product packaging.

Generally, in the case of performing multicolor recording by thermal recording, an electron-donating dye precursor (color former) which develops different hues by heating with different thermal energy.
And a acidic substance (developing agent), or a combination of a diazo compound (developing agent) and a coupling component (developing agent). As the multicolor heat-sensitive recording material, a multicolor heat-sensitive recording material having a multicolor heat-sensitive recording layer in which cyan, magenta and yellow color-developing unit layers are already provided on one surface of a support (Japanese Patent Application No. 59-162361). ) Is being developed.

[0004]

However, in the label field, a multicolor thermosensitive recording label having three or more colors has not been known yet. Therefore, the inventors of the present invention have a structure in which at least three heat-sensitive recording layers are provided on one surface of a support and an adhesive layer and a release sheet are sequentially provided on the other surface of the support to provide multi-color heat-sensitive recording of three or more colors. A label for use was prepared to complete the present invention. Therefore, it is an object of the present invention to provide a novel multicolor thermal recording label.

[0005]

The above objects of the present invention are as follows.
This is achieved by a multicolor thermosensitive recording label characterized in that at least three thermosensitive recording layers are provided on one side of a support, and at least an adhesive layer and a release sheet are sequentially provided on the other side.

Next, a method for easily obtaining a good multicolor image by using the multicolor thermosensitive recording label of the present invention will be described with reference to the drawings. In FIG. 1, a cyan coloring layer 2, a magenta coloring layer 1 and a yellow coloring layer 6 are provided on one surface of an opaque support 3.
FIG. 3 is a schematic cross-sectional view of a multi-color thermosensitive recording label of the present invention in which the pressure sensitive adhesive layer 4 and the release sheet 5 are sequentially provided on the other surface in order to provide a full color image.

In this case, in order to color each layer independently and bring a recorded multicolor image close to a natural color, at least the upper two color developing layers are disclosed in JP-A-61-40192. It is preferable to employ a system of a coupling coloring reaction of a diazo compound and a photofixing reaction.

That is, first, the uppermost yellow color forming layer 1 on one side is independently colored by thermal recording with low heat energy. After that, light fixing is performed using a light source of a specific wavelength that selectively photodecomposes only the yellow diazo compound. Next, the magenta color developing layer 2 having a higher thermal energy than that of the previous time and having a low heat sensitivity inside is thermally recorded so that the magenta color developing layer 2 is independently colored, and then only the magenta diazo is selectively photodecomposed at a specific wavelength. The light is fixed by using the light source. Furthermore,
The cyan color developing layer 3 inside the magenta layer 2 is thermally recorded with higher heat energy than the previous time, and color is independently developed. In this case, the cyan color forming layer 3 on the lowermost side of the three layers does not necessarily require optical fixing.

Therefore, in this case, since cyan, magenta, or yellow can be independently developed on one surface of the support, cyan, magenta, yellow, cyan + magenta (blue), magenta + yellow (red ), Cyan + yellow (green), cyan +
A total of 7 colors of magenta + yellow (black) are realized with good color separation.

It should be noted that any two layers among cyan color forming layer, magenta color forming layer and yellow color forming layer can be appropriately selected and sequentially provided on a support to thermally record a two-color or three-color image. Is natural. Further, those skilled in the art can easily understand that an intermediate color can be appropriately reproduced by appropriately controlling the applied heat energy to control the color development of each unit.

After the image is recorded in this manner, the release sheet on the back surface is peeled off and the product is attached to the product. However,
As a matter of course, the image may be recorded after being attached to the product. The method of using the multicolor thermosensitive recording label of the present invention has been schematically described above. Next, the materials used in the present invention will be described.

The material used for heat-sensitive recording according to the present invention is a material which causes a color-forming reaction upon contact of the material with heating, and specifically, an electron-donating dye precursor (color-forming agent) and an acidic material (developing agent). ) Or a combination of a diazo compound (color former) and a coupling compound (developer).

The electron-donating dye precursor in the former combination has a property of developing a color by donating an electron or accepting a proton such as an acid,
Although it is not particularly limited, it is generally colorless and has a partial skeleton such as lactone, lactam, sultone, spiropyran, ester, amide, etc., and these partial skeletons are opened or cleaved upon contact with a color developer. A compound is used. Specifically, crystal violet lactone, benzoyl leuco methylene blue, malachite green lactone, rhodamine B lactam, 1,3,3-trimethyl-
6'-ethyl-8'-butoxyindolinobenzospiropyran and the like.

As a developer for these color formers,
An acidic substance such as a phenol compound, an organic acid or a metal salt thereof, and an oxybenzoic acid ester is used. The developer preferably has a melting point of 50 ° C to 250 ° C, and particularly has a melting point of 6
Preference is given to a water-insoluble phenol or organic acid having a temperature of 0 ° C to 200 ° C. Specific examples of these color developing agents are described in, for example, JP-A-6-36.
No. 1-291183.

The diazo compound which can be used in the present invention is a compound which reacts with a color developing agent called a coupling component described later to develop a color, and decomposes when receiving a light of a specific wavelength before the reaction. However, even if the coupling component acts, it no longer has a coloring ability. The hue in this coloring system is mainly determined by the diazo dye produced by the reaction of the diazo compound and the coupling component.

Therefore, as is well known, the color hue can be easily changed by changing the chemical structure of the diazo compound or by changing the chemical structure of the coupling component. The hue can be obtained. For this reason, various diazo compounds may be contained in one layer and one type of coupling component and other additives may be incorporated in the same layer. In this case, each unit coloring group has different diazo compounds. It is composed of a compound, a coupling component and other additives which are common to others.

There is also a combination in which separate coupling components are contained in several layers, and the same diazo compound and other additives are incorporated in each layer. At this time, each unit coloring group is composed of a different coupling component, a diazo compound and an additive which are common to the other components. In any case, each unit coloring group
It is composed of one or more diazo compounds and one or more coupling components and other additives which are combined so as to have different coloring hues.

The photodecomposable diazo compound in the present invention mainly means an aromatic diazo compound, and more specifically, a compound such as an aromatic diazonium salt, a diazosulfonate compound, a diazoamino compound or the like. Next, a diazonium salt will be mainly described as a representative example. The diazonium salt is a compound represented by the general formula ArN ₂ ⁺ X ⁻ (wherein Ar represents a substituted or unsubstituted aromatic moiety, N ₂ ⁺ represents a diazonium group, and X ⁻ represents an acid). Represents an anion).

It is generally said that the photolysis wavelength of a diazonium salt is its absorption maximum wavelength. It is known that the absorption maximum wavelength of diazonium salt changes from about 200 nm to about 700 nm depending on its chemical structure (“Photolysis and chemical structure of photosensitive diazonium salt” by Takahiro Tsunoda and Ao Yamaoka, Japan photo Journal 29 (4) 197-105
Page (1965)).

That is, when a diazonium salt is used as a photodecomposable compound, it is decomposed by light having a specific wavelength according to its chemical structure, and if the chemical structure of the diazonium salt is changed, the same coupling component and coupling reaction can be obtained. The hue of the dye when it is changed also changes. Specific examples of the acid anion include C _n F
_{2 n + 1} COO ⁻ (n represents 3 to 9), C _m F
_{2 m +1} SO ₃ ^- _(m represents 2~8), PF ₆ ^-,
Examples thereof include compounds represented by BF ₄ ⁻ , B- (C ₆ H ₅ ) ₄ ^{− and the} like.

Many diazosulfonates that can be used in the present invention are known, and they can be obtained by treating each diazonium salt with a sulfite. The diazoamino compound that can be used in the present invention is a compound in which the diazo group is coupled with dicyandiamide, sarcosine, methyltaurine, N-ethylanthranic acid-5-sulphonic acid, monoethanolamine, diethanolamine, guanidine or the like. Is. Details of these diazo compounds are described in, for example, JP-A-2-
It is described in Japanese Patent No. 141276. When it is desired to form images of three or more colors independently, it is desirable to use two or more diazo compounds having different photolytic wavelengths.

The developer for the diazo compound used in the present invention is a coupling component which is coupled with the diazo compound to form a dye. Specific examples thereof include, for example, 2-hydroxy-3-naphthoic acid anilide,
Examples thereof include resorcin and those described in JP-A-62-146678. Further, by using two or more of these coupling components in combination, an image with any color tone can be obtained. Since the coupling reaction between these diazo compound and the coupling component easily occurs in a basic atmosphere, a basic substance may be added in the layer.

As the basic substance, a hardly water-soluble or water-insoluble basic substance or a substance which generates an alkali when heated is used. Examples thereof are inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, pyrroles, pyrimidines,
Piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles, morpholines, piperidines, amidines, formazines,
Nitrogen-containing compounds such as pyridines are mentioned. Specific examples of these are described, for example, in Japanese Patent Application No. 60-132990. Two or more basic substances may be used in combination.

The color former used in the present invention may be used as a solid dispersant, but from the viewpoint of raw storage stability of the thermosensitive recording layer (prevention of fog), such as preventing contact between the color former and the developer at room temperature, In addition, it is preferable to encapsulate and use the color former from the viewpoint of controlling the color development sensitivity such that the color is developed with desired heat energy.

Any of an interfacial polymerization method, an internal polymerization method, and an external polymerization method can be adopted for producing the microcapsules that can be used in the present invention. In particular, a core substance containing a color former is used. It is preferable to employ an interfacial polymerization method in which after emulsifying in a water-soluble polymer-dissolved aqueous solution, a wall of a polymer substance is formed around the oil droplets. The reactant forming the polymer substance is added inside the oil droplet and / or outside the oil droplet.

Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer,
Examples thereof include styrene-acrylate copolymer. Preferred polymeric substances are polyurethanes, polyureas, polyamides, polyesters and polycarbonates, particularly preferably polyurethanes and polyureas. Two or more polymer substances can be used in combination.

Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like. For example, when using polyurea as a capsule wall material, diisocyanate, triisocyanate, tetraisocyanate, polyisocyanate such as polyisocyanate prepolymer, and polyamine such as diamine, triamine, tetraamine, and two amino groups The microcapsule wall can be easily formed by reacting the prepolymer, piperazine or its derivative or the polyol, etc., contained above in an aqueous solvent by an interfacial polymerization method.

The composite wall made of polyurea and polyamide or the composite wall made of polyurethane and polyamide, for example, is prepared by using, for example, polyisocyanate and acid chloride or polyamine and polyol, after adjusting the pH of the emulsifying medium as the reaction liquid. It can be prepared by warming. Details of the method for producing a composite wall composed of these polyurea and polyamide are described in JP-A-58-6.
6948.

Further, a solid sensitizer may be added to swell the microcapsule wall during heating. As the solid sensitizer, those which are solid at room temperature and have a melting point of 50 ° C. or higher, preferably 120 ° C. or lower, can be selected from the plasticizers of polymers used for the microcapsule wall. For example, when the wall material is made of polyurea or polyurethane, a hydroxy compound, a carbamic acid ester compound, an aromatic alkoxy compound, an organic sulfonamide compound, an aliphatic amide compound, an arylamide compound or the like is preferably used.

In the present invention, a color forming aid can be used. The color-forming aid that can be used in the present invention,
It is a substance that raises the coloring density during heating recording or lowers the minimum coloring temperature.It has the effect of lowering the melting point of coupling components, basic substances, diazo compounds, etc., and lowering the softening point of the capsule wall. , Diazo, basic substance, coupling component, etc. are to be easily reacted.

Examples of the color-forming aid include phenol compounds, alcoholic compounds, amide compounds, sulfonamide compounds, and the like. Specific examples thereof include p-tert-octylphenol, p-benzyloxyphenol, phenyl p-oxybenzoate, Examples thereof include benzyl carbanylate, phenethyl carbanylate, hydroquinone dihydroxyethyl ether, xylylenediol, N-hydroxyethyl-methanesulfonic acid amide, N-phenyl-methanesulfonic acid amide. These may be contained in the core substance or may be added outside the microcapsules as an emulsified dispersion.

In the present invention, a substantially transparent thermosensitive coloring layer may be provided to improve the image quality of a multicolor image. In this case, the developer for the electron-donating dye precursor or diazo compound, which is a color former, is not solid-dispersed, but is dissolved in an organic solvent that is sparingly soluble or insoluble in water, and then this is used as a surfactant. And / or mixed with an aqueous phase having a water-soluble polymer as a protective colloid and used in the form of an emulsified dispersion. From the viewpoint of facilitating emulsion dispersion, it is preferable to use a surfactant.

The organic solvent used in this case can be appropriately selected, for example, from the high boiling point oils described in JP-A-2-141279. Among these, it is preferable to use the esters from the viewpoint of the emulsion stability of the emulsified dispersion, and above all, when tricresyl phosphate is used alone or as a mixture, the emulsion dispersion stability of the color developer is particularly good. Yes preferred. The above oils can be used together or with other oils.

In the present invention, an auxiliary solvent may be added to the above organic solvent as a dissolution aid having a low boiling point. As such an auxiliary solvent, for example, ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and the like can be mentioned as particularly preferable ones. In some cases, it is possible to use only the low-boiling auxiliary solvent without the high-boiling oil.

The water-soluble polymer to be contained as a protective colloid in the aqueous phase mixed with the oil phase containing these components is appropriately selected from known anionic polymers, nonionic polymers and amphoteric polymers. However, polyvinyl alcohol, gelatin, cellulose derivatives and the like are preferable.

As the surface active agent to be contained in the aqueous phase, an anionic or nonionic surface active agent which does not cause precipitation or aggregation by acting on the protective colloid may be appropriately selected and used. it can. Preferred surfactants include sodium alkylbenzene sulfonate, sodium alkylsulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (for example, polyoxyethylene nonylphenyl ether), and the like.

The emulsified dispersion of the present invention comprises means used for ordinary fine particle emulsification such as high speed stirring and ultrasonic dispersion of an oil phase containing the above components and an aqueous phase containing a protective colloid and a surfactant. It can be easily mixed and dispersed by using. Further, the ratio of the oil phase to the water phase (oil phase weight / water phase weight) is preferably 0.02 to 0.6, and particularly preferably 0.1 to 0.4. If it is 0.02 or less, the amount of the aqueous phase is too large and the layer becomes thin, so that sufficient color developability cannot be obtained.
On the contrary, when it is 0.6 or more, the viscosity of the liquid becomes high, which causes inconvenience of handling and deterioration of coating liquid stability.

For the heat-sensitive recording layer, a suitable binder is used for fixing various materials such as color-developing materials on the support or on the heat-sensitive recording layer or the intermediate layer which has already been coated. As the binder, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, arabic gum, gelatin, polyvinyl pyrrolidone, casein, styrene-butadiene latex,
Various emulsions such as acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester, ethylene-vinyl acetate copolymer and the like can be used. The amount used is 0.5 to 5 g / m ² in terms of solid content.

In the present invention, in addition to the above materials, citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid and the like can be added as an acid stabilizer. The thermal recording layer provided as described above has extremely good transparency. When it is not necessary to make the heat-sensitive recording layer transparent, a developer or the like may be used by solid dispersion with a sand mill or the like. in this case,
When the color former is not microencapsulated, the color former and the developer are separately dispersed in the water-soluble polymer solution. Preferred water-soluble polymers include water-soluble polymers used when making microcapsules. The size of the dispersed particles is preferably 10 μm or less.

In the present invention, it is preferable to provide a protective layer on the heat-sensitive recording layer. When the protective layer is provided on the uppermost layer of the heat-sensitive recording layer, the mechanical strength of the surface of the heat-sensitive recording layer is improved, and when it is provided as an intermediate layer between the heat-sensitive recording layers, a role of preventing unnecessary color mixing between layers. Can additionally be fulfilled. A pigment, a metal soap, a wax, a cross-linking agent and the like are added to the protective layer for the purpose of improving matching property with a thermal head during thermal recording and improving water resistance of the protective layer. Details of these pigments, metal soaps, waxes, crosslinking agents, etc. are described in, for example, JP-A-2-141279.

A surfactant is added to the coating liquid for forming the protective layer in order to form the protective layer uniformly on the heat-sensitive recording layer. Surfactants include sulfosuccinic acid-based alkali metal salts, fluorine-containing surfactants, etc.
Examples thereof include sodium salts or ammonium salts of (2-ethylhexyl) sulfosuccinic acid, di- (n-hexyl) sulfosuccinic acid and the like.

Further, in the protective layer, a surface active agent, a polymer electrolyte or the like for preventing the heat-sensitive recording material from being charged may be added. The solid coating amount of the protective layer is usually 0.2 to 5 g / m.
² is preferable, and more preferably 1 g to 3 g / m ² . When transparency is not required for the protective layer, a publicly known protective layer may be appropriately provided.

The support used in the present invention may be opaque or transparent. Examples of the opaque support include paper, synthetic paper, an aluminum vapor-deposited base, and a transparent support described below coated with a white pigment. As the paper used for the support, neutral paper having a heat extraction pH of 6 to 9 sized with a neutral sizing agent such as alkyl ketene dimer (for example, JP-A-55-14281) is used, and the storage stability with time is improved. Is advantageous.

On the other hand, examples of the transparent support include polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative films such as cellulose triacetate film, polystyrene films, polypropylene films, polyolefin films such as polyethylene films, polyimide films, and the like. A polyvinyl chloride film, a polyvinylidene chloride film, a polyacrylic film, a polycarbonate film and the like can be mentioned, and these can be used alone or by laminating, but it is particularly preferable to subject the polyester film to heat treatment and antistatic treatment. ..

The thickness of the transparent support is 20 to 200 μm.
m having a diameter of 50 to 100 μm is particularly preferable. In the present invention, when a polymer film support is used, it is preferable to provide an undercoat layer between the support and the thermosensitive recording layer in order to enhance the adhesiveness between them. As the material of the undercoat layer, gelatin or synthetic polymer latex,
Nitrocellulose or the like is used. The coating amount of the undercoat layer is preferably in the range of ^{0.1g / m 2 ~2.0g / m 2} , preferably in the range particularly ^{0.2g / m 2 ~1.0g / m 2} .

A hardener is used for the undercoat layer, because when the heat-sensitive recording layer is coated thereon, it may swell with water contained in the heat-sensitive recording layer and deteriorate the image quality of the heat-sensitive recording layer. It is desirable to cure by curing. Examples of the hardener include those described in JP-A-2-141279. The amount of these hardeners added is
An appropriate addition amount can be selected in the range of 0.20% by weight to 3.0% by weight based on the weight of the undercoat material, depending on the coating method and the desired degree of curing.

Depending on the curing agent used, if necessary, caustic soda may be added to bring the pH of the solution to the alkaline side, or the pH of the solution may be brought to the acidic side with citric acid or the like. It is also possible to add an antifoaming agent to eliminate bubbles generated during coating, or to add an activator to improve the leveling of the liquid and prevent the generation of coating streaks. ..

Further, before applying the undercoat layer, it is desirable to activate the surface of the support by a known method.
As a method of activation treatment, etching treatment with acid,
Flame treatment with a gas burner, corona treatment, glow discharge treatment, or the like is used, but from the viewpoint of cost or simplicity, US Pat. Nos. 2,715,075 and 2
The corona discharge treatments described in No. 846,727, No. 3,549,406, No. 3,590,107 and the like are most preferably used.

The heat-sensitive recording material used in the heat-sensitive recording label of the present invention includes microcapsules containing an electron-donating dye precursor or a diazo compound, and a dispersion in which at least a color developer is emulsified and dispersed, a binder and other additives. To prepare a coating solution containing, bar coating, blade coating, air knife coating, gravure coating, roll coating coating, spray coating on a support such as high quality paper or the film,
It is produced by coating and drying by a coating method such as dip coating and providing a thermosensitive recording layer having a solid content of 2.5 to 25 g / m ² .

If desired, US Pat. No. 2,761,7
No. 91, No. 3,508,947, No. 2,941,
No. 898 and No. 3,526,528, Yuji Harasaki, “Coating Engineering”, page 253 (Published by Asakura Shoten in 1973) It is also possible, and an appropriate method can be selected depending on the coating amount, coating speed, and the like. The pigment dispersion, the thickener, the flow modifier, the defoaming agent, the defoaming agent, the release agent, the colorant, and the like may be appropriately added to the coating liquid used in the present invention as necessary without impairing the properties. As long as it doesn't matter.

An adhesive layer was formed on the back surface (the surface opposite to the surface on which the recording layer was provided) of the heat-sensitive recording material prepared in the above-described manner.
Providing a release sheet and press-bonding the release sheet to produce a multicolor recording label can be easily performed by the above-mentioned known coating method and sticking technique. The adhesive used for the adhesive layer of the present invention is not particularly limited, and a known pressure-sensitive adhesive can be used.

A heat-sensitive adhesive may be used in place of the pressure-sensitive adhesive to eliminate the need for a release sheet. As the pressure-sensitive adhesive used in the present invention, for example, an acrylic resin copolymer having acid groups esterified with a basic substance is emulsified and dispersed in an aqueous phase to form an emulsion, and further a tackifier or a softening agent is appropriately added. Examples thereof include acrylic resin adhesives to which agents have been added.

Specific examples of the acrylic resin copolymer include acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid butyl ester, 2-ethylhexyl acrylate, octyl acrylate, decyl acrylate, and other alkyl acrylates, One or one selected from methacrylic acid alkyl esters such as methacrylic acid methyl ester, methacrylic acid ethyl ester, methacrylic acid butyl ester, 2-ethylhexyl methacrylic acid, octyl methacrylic acid, and decyl methacrylic acid. To mention a copolymer obtained by copolymerizing one or more monomers selected from the above monomers, acrylic acid, methacrylic acid, and maleic acid, and optionally styrene, vinyl acetate, etc. You can

Examples of the tackifier include rosin and styrene resin. Examples of the softening agent include polybutene and wax. The heat-sensitive adhesive used in the present invention refers to an adhesive that does not have tackiness or adhesiveness before being heated, and causes adhesiveness and the like by being heated. Examples of such a heat-sensitive adhesive include those containing a thermoplastic resin such as a vinyl resin or an acrylic resin as a main component.

The release sheet used in the present invention is not particularly limited, and may be appropriately selected from among known release sheets in which a release layer made of a silicone resin or the like is provided on paper or a synthetic resin sheet. You can In the multicolor thermosensitive recording label according to the present invention, the adhesive is applied to the upper surface of the release sheet by a known application means to provide an adhesive layer, and the back surface of the thermosensitive recording material (recording layer is provided on the adhesive layer. It can be easily obtained by stacking (pressurizing surface and the opposite surface) and press-bonding.

In the present invention, when paper is used as the support, when the organic solvent contained in the adhesive layer peels off the release sheet and attaches the heat-sensitive recording label to a vinyl chloride film, etc. The plasticizer contained in the vinyl film may penetrate and permeate the paper as the support and react with the dye in the heat-sensitive recording layer to cause the recorded image to disappear. Between the adhesive layer, polyvinyl alcohol, carboxyl cellulose, starch,
It is preferable to provide a barrier layer containing a water-soluble polymer substance such as gelatin.

The multicolor heat-sensitive recording label of the present invention can be used as a multicolor heat-sensitive recording label for a printer of a facsimile or an electronic computer which requires high-speed recording. When a diazo compound is used as a color former and is subjected to photofixation, an exposure zone for photodecomposition is provided.

The arrangement of the recording head and the exposure zone is roughly classified into two types. One is that after recording once, light irradiation for photolysis is performed, and before and after this light irradiation, the recording material is in the recording waiting state so that it can be recorded again at the place where it was once recorded by the recording material feeding mechanism. Then, the recording material is radiated again, the recording material is irradiated again, and the recording material is returned to its original shape. This is a so-called 1-head multi-scan method. It is a so-called multi-head one-scan method that has a light irradiation zone between them, and both methods may be combined if necessary, and the thermal energy applied to the head can be changed as necessary. May be.

As the light source for photolysis, various light sources which emit light of a desired wavelength can be used. For example, various fluorescent lamps, xenon lamps, xenon flash lamps, mercury lamps of various pressures, photographic flashes, Various light sources such as a strobe can be used. Further, in order to make the light fixing zone compact, the light source section and the exposure section may be separated by using an optical fiber. In some cases, a recording material that has been once recorded may be placed under sunlight or fluorescent light, fixed mainly with light in the visible light region, and then printed again to obtain a multicolor sample.

[0060]

As described in detail above, according to the multicolor heat-sensitive recording label of the present invention, it is possible to heat-record a multicolor image which cannot be heat-recorded by the conventional single-color heat-sensitive recording label. You can

[0061]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. In addition, "part" indicating the addition amount represents "part by weight".

Example 1. (1) Preparation of third thermosensitive recording layer liquid [Preparation of capsule liquid of electron-donating dye precursor] Crystal violet lactone which is an electron-donating dye precursor
After dissolving 3.0 parts in 20 parts of ethyl acetate, 20 parts of alkylnaphthalene, which is a high boiling point solvent, was added and heated to be mixed uniformly. Next, as a capsule wall agent in this mixed solution,
20 parts of xylylene diisocyanate / trimethylolpropane adduct was added and stirred uniformly.

Next, a 6 wt% aqueous solution of separately prepared polyvinyl alcohol (polymerization degree 1700, saponification degree 88%) 5
The above electron-donating dye precursor solution was added to 4 parts, and the mixture was emulsified and dispersed using a homogenizer. 68 parts of water was added to the obtained emulsion for homogenization, the temperature was raised to 50 ° C. with stirring, and the encapsulation reaction was carried out for 3 hours to obtain a target capsule solution. The average particle size of the capsule was 1.6 μm.

[Preparation of Dispersion of Electron-Accepting Compound] 30 parts of bisphenol A, which is an electron-accepting compound, was added to 150 parts of a 4% by weight aqueous solution of polyvinyl alcohol, and the mixture was dispersed for 24 hours using a ball mill to obtain a dispersion. It was made. The average particle size of the electron-accepting compound in the dispersion was 1.2 μm.

[Preparation of Coating Liquid] The above electron-donating dye precursor capsule liquid and the electron-accepting compound dispersion liquid were mixed so that the ratio of the electron-donating dye precursor / electron-accepting compound was 1/2. To prepare a coating solution.

(2) Preparation of second thermosensitive recording layer liquid [Preparation of capsule liquid of diazo compound] 4- (N- (2-
(2,4-di-tert-amylphenoxy) butyryl) piperazinobenzenediazonium hexafluorophosphate 2.0 parts was dissolved in 20 parts ethyl acetate, and then 20 parts of a high boiling solvent alkylnaphthalene was added and heated. And mixed evenly. Next, xylylene diisocyanate /
15 parts of trimethylolpropane adduct was added and stirred uniformly.

Next, a 6 wt% aqueous solution of separately prepared polyvinyl alcohol (polymerization degree 1700, saponification degree 88%) 5
To 4 parts, add the solution in which the diazo compound is dissolved,
It was emulsified and dispersed using a homogenizer. 68 parts of water was added to the obtained emulsion to homogenize it, and the mixture was stirred at 40 ° C.
The temperature was raised to 3, and the encapsulation reaction was performed for 3 hours to obtain a capsule liquid. The average particle size of the capsule was 1.1 μm.

[Preparation of Coupler Dispersion] 10 parts of 1- (2′-octylphenyl) -3-methyl-5-pyrazolone as a coupler and 20 parts of dodecyl parahydroxybenzoate were added to a polyvinyl alcohol 4% by weight aqueous solution. 150
It was added to each part and dispersed using a ball mill for 24 hours to prepare a dispersion liquid. The average particle size of the coupler in the dispersion is 1.
It was 2 μm.

[Preparation of Coating Liquid] The above-mentioned diazo compound capsule liquid and coupler dispersion liquid were mixed at a diazo compound / coupler ratio of 2/3 to prepare a coating liquid. (3) Preparation of first thermosensitive recording layer liquid [Preparation of capsule liquid of diazo compound] 2,5-dibutoxy-4-tolylthiobenzenediazonium hexafluorophosphate: 3.0 parts was dissolved in 20 parts of ethyl acetate. After that, 20 parts of a high boiling point solvent, alkylnaphthalene, was added and heated to uniformly mix. Next, 15 parts of xylylene diisocyanate / trimethylolpropane adduct as a capsule wall agent was added to the obtained mixed liquid,
Stir evenly.

Next, a 6 wt% aqueous solution of separately prepared polyvinyl alcohol (polymerization degree 1700, saponification degree 88%) 5
The above solution of the diazo compound was added to 4 parts and emulsified and dispersed using a homogenizer. 68 parts of water was added to the obtained emulsion to homogenize it, and then the temperature was raised to 40 ° C. with stirring and 3
The encapsulation reaction was performed for a time to obtain a capsule liquid. The average particle size of the capsule was 1.0 μm.

[Preparation of Coupler Dispersion] 2-Chloro-5
-Octylacetoacetanilide as coupler 10
Parts, 5 parts of 1,2,3-triphenylguanidine as an organic base and 20 parts of dodecyl parahydroxybenzoate were added to 200 parts of a 4% by weight polyvinyl alcohol aqueous solution,
A ball mill was used for dispersion for 24 hours to prepare a dispersion liquid. The average particle size of the dispersion was 1.2 μm.

[Preparation of Coating Liquid] The capsule liquid of the diazo compound and the coupler dispersion liquid were mixed so that the ratio of the diazo compound / coupler was 4/5 to prepare a coating liquid.

(4) Preparation of coated recording paper A A high- quality paper having a basis weight of 50 g / m ² was used as a support, and a wire bar was provided on one side of the third and second thermosensitive recording layers,
The intended multicolor thermosensitive recording paper A was obtained by sequentially applying and drying the first thermosensitive recording layer in this order. The coating amounts as solids were 5.2 g / m ² , 6.3 g / m ² and 6.8 g / m ² , respectively.

(5) Preparation of release label A for thermal recording recording Weighing 50 g / m ² On a surface of a release paper obtained by providing a silicone resin layer on a high-quality paper, an adhesive layer composition as a thickness after drying was prepared. Of the acrylic resin copolymer (S
-3001 (pH 6.5): a product name of Nippon Carbide Industry Co., Ltd.) A 45% by weight aqueous emulsion was applied to form an adhesive layer. The surface (back surface) of the recording paper A opposite to the recording layer was pressure-bonded to the adhesive layer surface of the release paper thus obtained to obtain a multicolor thermosensitive recording label A of the present invention.

Thermal recording test A thermal head (KST type) manufactured by Kyocera Corporation was used on the surface of the recording layer of the multicolor thermal recording label A so that the recording energy per unit area was 25 mJ / mm ^2. The power applied to the head and the pulse width were determined, and after thermally printing on the first thermosensitive recording layer to obtain a yellow image, the whole surface was irradiated with light for 10 seconds using an ultraviolet lamp with an emission center wavelength of 420 nm and an output of 40 W.

Then, the applied power to the thermal head and the pulse width were determined so that the recording energy per unit area was 40 mJ / mm ^2, and thermal printing was performed on the second thermosensitive recording layer to obtain a magenta image, and then the light was emitted. Center wavelength is 365
The whole surface was irradiated with light for 15 seconds using a UV lamp having a wavelength of 40 W and an output of 40 W.

Finally, the applied power to the thermal head and the pulse width were determined so that the recording energy per unit area was 60 mJ / mm ^2, and thermal printing was performed on the third thermosensitive recording layer to obtain a cyan image. This gives magenta,
Image recordings of yellow, cyan, cyan + magenta (blue), magenta + yellow (red), cyan + yellow (green) and cyan + magenta + yellow (black) were obtained. The unrecorded area was grayish white, and it was confirmed that the image clarity was excellent. When the release paper was peeled off from the obtained recording label and attached to the product, it was an extremely high-quality label.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a multicolor thermosensitive recording label of the present invention.

[Explanation of symbols]

 1 Magenta Coloring Layer 2 Cyan Coloring Layer 3 Support 4 Adhesive Layer 5 Release Sheet 6 Yellow Coloring Layer

Claims (1)

[Claims] 1. A multicolor thermosensitive recording label comprising at least three thermosensitive recording layers provided on one surface of a support, and at least an adhesive layer and a release sheet sequentially provided on the other surface.