JP2009149788A - Color variable ink and printed matter - Google Patents

Abstract

Kind Code: A1 To provide a color variable ink whose hue is changed by applying or dipping a chemical such as an organic solvent with water-based gravure ink or UV ink, and a printed matter using the ink.
The present invention relates to a color variable ink containing a dye in a varnish, using a water-insoluble organic solvent-soluble oil-soluble dye as a colorant and kneading into a desired varnish. In addition, the present invention provides a color variable ink and a printed matter using the ink, which are capable of producing water-based gravure ink, ultraviolet curable offset ink, or ultraviolet curable intaglio ink.
[Selection] Figure 1

Description

  The present invention is a printing ink and printed matter for imparting resistance to chemical tampering that erases the postmarks or splits of printed matter and reuses the printed matter, and the ink comprises an oil-soluble dye, a colored pigment, Consists of auxiliary agents such as varnishes, extender pigments, additives, etc., relating to securities such as stamps, stamps, certificate papers, etc., and inks and printed matter with excellent anti-tampering properties for security such as various certificates and important documents is there.

  Securities such as stamps and stamps, and printed materials such as various certificates and important documents have a discoloration effect on paper, ink, etc. in order to prevent erasure by organic solvents such as postmarks or tallys printed on printed materials, etc. There is a method of preventing falsification or the like by blending materials to prevent tampering, and when the printed matter comes into contact with an organic solvent or the like, the ink or paper used for the printed matter changes color.

  For example, as an ink for preventing counterfeiting such as tampering, an ink characterized by containing aminoiminoisoindolenine and a metal compound in a petroleum solvent and preventing forgery such as tampering by discoloring the ink. Yes (see, for example, Patent Document 1).

  In addition, there is an ink characterized by containing a spiropyra compound or the like in an oil-based vehicle, etc., and discoloring or decoloring by contact with chemicals, etc., and preventing counterfeiting such as tampering with chemicals (for example, patents) Reference 2).

  And a compound comprising at least one compound capable of forming a binder matrix and at least one dye sensitive to organic solvents and / or other chemicals to form the binder matrix, There are exudable inks characterized by being selected from compounds capable of forming a solid binder matrix by polymerization and / or cross-linking action (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 04-293977 JP 05-156193 A Japanese National Patent Publication No. 11-510548

  However, the oil-based inks and the like disclosed in JP-A-4-293777 have a problem that they may adversely affect the work environment and the human body because they contain organic solvents.

  In addition, the oil-based ink of JP-A No. 05-156193 is cured by oxidative polymerization, so that it takes time to dry the ink film, and there is a problem that the printed matter may be set off.

  In addition, when the ink of JP-A-11-510548 is used as a UV curable ink, the dye or resin is cross-linked three-dimensionally, and bleeding occurs when the solvent penetrates into the cross-link. Therefore, there is a problem that the presence or absence of tampering cannot be confirmed unless the printed matter is immersed in an organic solvent for about 5 minutes.

  The present invention relates to an aqueous gravure ink containing a colorant in a water-soluble varnish obtained by neutralizing an acrylic resin containing a carboxyl group and / or a hydroxyl group with a volatile base, and the colorant is at least 0.1 to 20% by weight. One kind of water-insoluble and organic solvent-soluble oil-soluble dye and 1 to 20% by weight of a coloring pigment or a coloring pigment is not contained, and the varnish is an acrylic containing a carboxyl group and / or a hydroxyl group. It is characterized by being a color variable ink containing 10 to 40% by weight of a resin and containing at least the aforementioned colorant and varnish.

  The present invention also relates to an ultraviolet curable offset ink containing a colorant in a varnish mainly composed of a monofunctional group and / or a bifunctional acrylate monomer, wherein the colorant is 5 to 20% by weight of at least one kind of water. Insoluble and organic solvent-soluble oil-soluble dye and 5 to 20% by weight of a coloring pigment or not containing the coloring pigment, the varnish contains 50 monofunctional groups and / or bifunctional acrylate monomers. It is a color variable ink containing at least 80% by weight and containing at least the above-mentioned colorant and varnish.

The present invention also includes a colorant and an extender pigment in a varnish comprising a UV-curable component obtained by carboxylating a monofunctional acrylate monomer containing a hydroxyl group with an acid anhydride and an oxidation-polymerized component of an alkali-soluble alkyd resin. In the ultraviolet curable intaglio ink, the colorant is 10 to 20% by weight of at least one water-insoluble and organic solvent-soluble oil-soluble dye and 5 to 20% by weight of a color pigment, 20 to 45% by weight, and the varnish contains 35 to 60% by weight of a monofunctional group and / or a bifunctional acrylate monomer, and includes at least the above-described colorant, extender pigment and varnish. It is characterized by being ink.

In addition, the present invention is a printed matter having at least one color variable region printed with the above-described color variable ink.

The present invention also includes at least a first region and / or a second region printed with at least one color variable ink, and at least a third region printed with an ink not containing an oil-soluble dye. In the printed matter having at least two or more types of printing areas selected from the above, the hue of at least two of the above-described at least two or more types of printing regions is a uniform color printed matter.

  The color variable region in the printed matter of the present invention is a printed matter having a color difference of ΔE26 or more based on the JIS color system, the hue before applying or immersing the organic solvent and the hue after applying or immersing the organic solvent. It is characterized by being.

  The color variable ink of the present invention has the effects of improving the printing work environment and ensuring the safety to the human body, as compared with oil-based inks using organic solvents.

Moreover, when the color variable ink of the present invention is used as a UV curable ink, the color variable ink is superior in drying property to the oxidation polymerization type ink.

In addition, the color variable ink of the present invention changes the hue instantaneously when it comes into contact with specific chemicals, organic solvents and other chemical substances used for chemical tampering. The effect that can be prevented.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the present invention is not limited to the best mode for carrying out the invention described below, and various other embodiments are included within the scope of the technical idea described in the scope of claims. .

  As the oil-soluble dye used in the color variable ink of the present invention, known ones can be used as long as they are water-insoluble and soluble in organic solvents, but preferably soluble in organic solvents such as ketones and esters. It shows sex. Further, although one kind of oil-soluble dye can be used, it is preferable to use two or more kinds. This is because some oil-soluble dyes do not dissolve in a specific organic solvent, and it may be difficult for one kind to react with all known organic solvents.

In addition, by combining two or more types of oil-soluble dyes having different solubility in various organic solvents, it is possible to impart two or more types of hue changes to the printed material in response to tampering of the printed material with a specific organic solvent. The effect of preventing falsification of printed matter can be improved.

The oil-soluble dye is a dye mainly used for coloring organic solvents, synthetic resins, oils and fats, and is characterized in that the target product is often colored by a simple dissolution phenomenon. The term “oil-soluble” as used herein includes not only a narrow meaning of being soluble in fats and oils but also a meaning of being soluble in many organic solvents other than water. That is, it is a dye that has no water-soluble group and is soluble in fats and oils and hydrocarbons, and is used for coloring fats and oils, gasoline, soap, butter, black ink, plastics and the like.

In general, oil-soluble dyes are classified according to their chemical structure. Yellow, orange, brown, and red dyes are mostly azo dyes, and purple, blue, and green dyes are anthraquinone and phthalocyanine dyes. Many blacks include those belonging to azines such as nigrosine. The organic solvent used in the present invention is described in “Dye Handbook” (edited by the Society of Synthetic Organic Chemistry “Dye Handbook”: published by Maruzen, 1970), and the color index (C The type can be specified by. As an example, C.I. I. The 12715 red dye is soluble in organic solvents such as acetone, ethanol and cellosolve. In addition, C.I. I. The 12195 black dye is soluble in organic solvents such as lower aliphatic alcohols, glycols, ethers, esters and ketones.

As the organic solvent, polar solvents such as alcohols such as ethyl alcohol, isopropyl alcohol, normal propyl alcohol and butyl alcohol, nonpolar solvents such as aromatic hydrocarbons such as benzene, toluene and xylene, gasoline, Aliphatic hydrocarbons such as petroleum, benzine and mineral spirits, halogenated hydrocarbons such as trichloroethylene, perchloroethylene and chloroform, ketones such as acetone, acetonitrile, diisobutyl ketone, diethyl ketone and dipropyl ketone, ethyl acetate and Well-known organic solvents, such as acetate esters, such as butyl acetate, are mentioned.

The color pigment used in the color variable ink of the present invention is not particularly limited, and may be a pigment or a pigment dispersed in water such as an aqueous slurry or press cake. Organic pigments, inorganic pigments, and the like are known pigments. Can be used. For example, in the case of gravure ink, pigments such as carbon black, phthalocyanine blue, phthalocyanine green, permanent red, dioxazine-based, quinacridone-based, azo-based metal complex, and selenium blue can be used.

Further, for example, the coloring pigment in the ultraviolet curable offset ink or the oxidative polymerization combined ultraviolet curable intaglio ink is an organic pigment dyed lake pigment such as an acid dye-based lake or a basic dye-based lake, monoazo yellow, disazo yellow, β -Insoluble azo pigments such as naphthol, naphthol AS, pyrazolone and benzimidazolone, azo pigments such as condensed azo pigments and azo lake pigments, phthalocyanine, quinacridone, anthraquinone, perylene, perinone, Condensed polycyclic pigments such as indigo, dioxazine, quinophthalone, isoindolinone and diketopyrrolopyrrole can be used. Examples of inorganic pigments include metal oxide pigments such as titanium dioxide, zinc oxide and iron black, complex oxide pigments such as cobalt green, cobalt blue and cobalt black, metal complex pigments such as ultramarine and bitumen, aluminum Known inorganic pigments such as paste, aluminum flake powder, metal powder pigments such as bronze powder and zinc powder, carbon black and pearl luster pigment can be used.

As extender pigments, known extender pigments such as calcium carbonate, kaolin clay, talc, bentonite, mica, barium sulfate, silica and aluminum hydroxide can be used. In addition, when using an extender pigment about water-based gravure ink and ultraviolet curable offset ink, it is preferable to make it 0 to 10weight%. This is to prevent gelation of the ink by the extender pigment.

Further, the color variable ink of the present invention can contain an antifoaming agent, a dispersing agent, a lubricant and the like as required.

  Moreover, the base material to which the color variable ink of the present invention is printed is not particularly limited, and can be printed on paper, plastic, film, metal plate and the like.

  In addition, as an application example of the color variable ink of the present invention, the printing method on the substrate is not particularly limited, and an offset printing method, a gravure printing method, a screen printing method, a flexographic printing method, an intaglio printing method, etc. A known printing method can be used. Next, the case where the color variable ink of the present invention is used as an aqueous gravure ink will be described as an example.

(In the case of water-based gravure ink)
When the color variable ink of the present invention is used as a water-based gravure ink, the oil-soluble dye may be blended in an amount of 0.1 to 20% by weight, a coloring pigment in an amount of 1 to 20% by weight, and an auxiliary agent in an amount of 60 to 88% by weight. preferable. This is to obtain good pigment dispersibility, ink fluidity, printability and the like. In particular, it is particularly preferable to neutralize an acrylic resin containing a carboxyl group with a volatile base to give a water-soluble varnish component of 1 to 20% by weight of a pigment used as a colorant, an oil-soluble dye 0 .5 to 20% by weight and auxiliary agent 70 to 88% by weight. In addition, the adjuvant in this invention contains organic solvents, such as water and alcohol, an antifoamer, a dispersing agent, a lubricant.

  Moreover, as a binder component of the above-mentioned varnish, a well-known binder component can be used, and water-soluble resin, water-dispersible resin, the intermediate | middle hydrosol type resin, etc. can be used. Specifically, shellac, rosin-modified maleic acid resin, styrene-acrylic acid resin, acrylic acid ester-acrylic acid resin, styrene-maleic acid resin, hydroxyethyl cellulose, hydroxypropyl cellulose, urethane-modified acrylic acid resin, water-soluble urethane, Examples thereof include a resin composed of a water-soluble polyester resin alone or a mixture thereof, a colloidal aqueous resin using a water-soluble resin as a protective colloid, and the like. Among these, acrylic resins having a carboxyl group are suitable for aqueous gravure ink, particularly from the viewpoint of printed matter quality, but those having a carboxyl group made of a mixed resin may also be used. Colloidal disversion type and emulsion type inks may also be used. The weight average molecular weight of the acrylic resin having a carboxyl group used for the water varnish is preferably a polymer in the range of 3000 to 50000.

  In addition, the water-based gravure ink contains 0.5 to 20% by weight of an oil-soluble dye and 1 to 20% by weight of a color pigment as a colorant with respect to a water-soluble varnish, and alcohol or the like is added in addition to the above components. It is adjusted by doing. Water-based gravure ink should be adjusted by adding a dispersant, antifoaming agent, wax, lubricant, etc., if necessary, and dissolving or dispersing in water with a dispersing machine such as a ball mill, attritor or sand mill. You can also. The ratio of the oil-soluble dye and the color pigment to the resin component of the water-soluble varnish is preferably 0.5 to 20% by weight of the oil-soluble dye and 1 to 20% by weight of the color pigment. This is because when the coloring pigment is added in an amount of 1 to 20% by weight and the oil-soluble dye is added in an amount of 20% by weight or more with respect to the water-soluble varnish component, the storage stability of the ink and the fastness of the printed matter may be deteriorated. Conversely, when the amount of the oil-soluble dye is less than 0.5% by weight relative to 1 to 20% by weight of the pigment, the hue change of the printed matter due to the organic solvent may be poor.

  As the organic solvent used in the water-based gravure ink, a known organic solvent can be used. However, the organic solvent has good solubility in the resin and has no problem in the synthesis of the resin. Those that are easily solventable and those that are miscible with water are preferred. For example, as such a solvent, methanol, ethanol, n-propanol, isopropanol, glycol ethers and the like are particularly preferable.

  Moreover, as a volatile basic compound used when neutralizing the carboxyl group of the acrylic resin used for the binder with a basic compound and making the resin hydrophilic and dispersing in water, for example, ammonia , Organic amines such as triethylamine, tributylamine, dimethylethanolamine, diisopropanolamine, and mormarin.

  Moreover, it is preferable to make the ratio of a coloring pigment and the resin which has the carboxyl group of a binder into the range to about twice with respect to a coloring pigment. This is because when the solid content of the resin is less than 1% with respect to the color pigment, it becomes difficult to disperse the color pigment sufficiently finely. Moreover, when more than about twice, the ratio of the color pigment in a dispersion will decrease, and when the aqueous pigment dispersion is used for printing ink etc., there will be no freedom in blending design. Next, the case where the color variable ink of the present invention is used as an ultraviolet curable ink will be described.

(In the case of UV curable offset ink)
When the color variable ink of the present invention is used as an ultraviolet curable offset, the oil-soluble dye is 5 to 20% by weight, the color pigment containing an organic pigment and an inorganic pigment is 5 to 20% by weight, the crosslinking density is low, and the number of functional groups It is preferable to make it 50 to 80 weight% of varnish which has as a main component an acrylate monomer with few. Particularly preferred is 10 to 15% by weight of an oil-soluble dye, and 5 to 10% by weight of a colored pigment containing an organic pigment and an inorganic pigment. The blending ratio is used to obtain good pigment dispersibility, ink flow characteristics, printability, and the like.

Further, in order to impart resistance to chemical acts that are reused by erasing postmarks or tally marks, coloring is applied to varnish 70 to 80% by weight based on an acrylate monomer having a low crosslinking density and a small number of functional groups. The oil-soluble dye used in the agent is preferably 10 to 15% by weight and the color pigment is preferably 5 to 10% by weight.

  As the varnish component of the UV curable offset ink, it is desirable to use a monofunctional acrylate monomer (for example, ECH-modified phenoxy acrylate) as a base so that the ink film containing the oil-soluble dye can be sufficiently brought into contact with the chemical. The monofunctional acrylate monomer has a structure having one acryloyl group in the molecule, and generally has a low viscosity and the cured product is flexible and has good adhesion. On the other hand, there are drawbacks that the curing rate is slow and the strength of the cured film is weak. In order to increase the viscosity without reducing the curability of the material, diallyl phthalate resin (for example, Daiso Dup Monomer (Daiso Co., Ltd.), ketone resin (for example, Hilac 110H Hitachi Chemical Co., Ltd.), acrylic resin (for example, , MM-428 Fujikura Kasei Co., Ltd.) and bifunctional acrylate oligomers (for example, urethane acrylate) may be used to adjust the viscosity.

  Further, even in a varnish mainly composed of a bifunctional acrylate monomer (for example, caprolactone-modified hydroxypivalate ester neopentyl glycol), the oil-soluble dye in the ink film can be sufficiently brought into contact with a chemical such as an organic solvent. . However, in the case of binders based on trifunctional (eg PO-modified glycerol triacrylate) or polyfunctional acrylate monomers (eg dipentaerythritol penta and hexaacrylate based polyfunctional monomer mixtures), the crosslinking density is It is considered that it is difficult for the oil-soluble dye in the ink film containing the oil-soluble dye, which is too high, to sufficiently come into contact with a chemical such as an organic solvent.

The UV curable offset ink is prepared by mixing 5 to 20% by weight of the oil-soluble dye described above, 5 to 20% by weight of the color pigment, and 50 to 80% by weight of the varnish, and mixing them. Can be produced. The ultraviolet curable offset ink can be provided with additives such as wax and dispersant as required.

(In the case of UV curable intaglio ink)
When the color variable ink of the present invention is used as an ultraviolet curable intaglio ink, the oil-soluble dye is 10 to 20% by weight, the color pigment containing the organic pigment and the inorganic pigment is 5 to 20% by weight, and the extender pigment is 20 to 20%. A combination of 45 wt% and 35 to 60 wt% of a varnish mainly composed of an acrylate monomer having a low crosslinking density and a small number of functional groups is preferred. Particularly preferred is a combination of 15 to 20% by weight of an oil-soluble dye, 5 to 20% by weight of a color pigment containing an organic pigment and an inorganic pigment, and 30 to 40% by weight of an extender pigment. The above formulation is for obtaining good pigment dispersibility, ink flow characteristics, printability and the like.

Further, in order to impart resistance to chemical acts that are reused by erasing the postmarks or tally marks, coloring is performed on 40 to 50% by weight of a varnish mainly composed of an acrylate monomer having a low crosslinking density and a small number of functional groups. It is desirable that the oil-soluble dye used in the agent is 15 to 20% by weight, the color pigment is 5 to 15% by weight, and the extender pigment is 30 to 40% by weight.

The varnish component of the UV curable intaglio ink is composed of a UV curable composition and an oxidative polymerization combined composition, and the UV curable varnish component is mainly composed of a monofunctional acrylate monomer containing a hydroxyl group and is dissolved in an alkaline solution. What was carboxylated with an anhydride was used, and an alkali-soluble alkyd resin was used as the oxidative polymerization varnish component.

The ultraviolet curable intaglio ink comprises 10 to 20% by weight of the oil-soluble dye described above, 5 to 20% by weight of the color pigment, 20 to 45% by weight of the extender pigment, and 35 to 60% by weight of the varnish. It can mix and can produce with a 3 roll mill. If necessary, additives such as waxes and dispersants can be added.

Hereinafter, the color variable ink of the present invention will be described in detail with specific examples.

Examples 1 and 2 are examples in which the color variable ink of the present invention is used as an aqueous gravure ink. Moreover, Comparative Example 1 and Comparative Example 2 are inks that do not contain an oil-soluble dye, and show the difference in the effect of the organic solvent from the ink of the present invention. As the oil-soluble dye, “trade name Oil Black DA-411” (manufactured by Arimoto Chemical Co., Ltd.) was used. The chemical formula of the above product is C ₂₉ H ₂₄ N ₆ , the appearance is a black powder, hardly dissolves in water, about 6% for methanol and butanol, and 10 for methyl ethyl ketone and xylene. % Dissolved. As the coloring pigment, a known pigment such as an azo pigment was used. Moreover, what used the varnish to be used contained the acrylic resin containing the carboxyl group neutralized with ammonia, or the polycarbodiimide type resin which has a carbodiimide group. The auxiliary agent used contained water and isopropyl alcohol.

Example 1
[Composition of green water-based gravure ink]
Oil-soluble dye 0.5% by weight
Azo-based yellow pigment 1% by weight
Acrylic resin 10% by weight
Polycarbodiimide resin 9.1% by weight
Auxiliary agent 79.4% by weight

(Example 2)
[Composition of gray aqueous gravure ink]
Oil-soluble dye 1% by weight
Azo-based red pigment 0.5% by weight
Azo-based yellow pigment 2% by weight
Acrylic resin 12% by weight
Auxiliary agent 84.5% by weight

In order to compare the change of the hue with respect to the solvent with the color variable ink of this invention, the composition of the ink of a comparative example is illustrated. As the coloring pigment, known pigments such as phthalocyanine pigments and azo pigments were used. As the varnish, an acrylic resin was used. The auxiliary agent used contained water and isopropyl alcohol.

(Comparative Example 1)
[Composition of green water-based gravure ink]
Phthalocyanine green pigment 2% by weight
Azo-based yellow pigment 9% by weight
Black pigment 0.5% by weight
Acrylic resin 10% by weight
Auxiliary agent 78.5% by weight

(Comparative Example 2)
[Composition of black aqueous gravure ink]
Azo-based yellow pigment 0.1% by weight
2% by weight of black pigment
Acrylic resin 10% by weight
Auxiliary agent 87.9% by weight

  The aqueous gravure inks of Example 1 and Example 2 and Comparative Example 1 and Comparative Example 2 were filled in the image area of the gravure plate having a solid part (number of lines: 175 lines) and a plate depth of 20 μm, and coated paper Printed. After a few days, the printed matter printed with each aqueous gravure ink is immersed for 5 seconds using reagent-grade acetone (Wako Pure Chemical Industries, Ltd.) and reagent grade ethyl acetate (Wako Pure Chemical Industries, Ltd.). The hue change of the printed material was evaluated visually and with a spectrophotometer.

  For the hue and color difference of the printed material, the hue (L *, a *, b *) of the printed material was measured using a GretagMacbeth spectrophotometer (manufactured by SpectroEye Gretag), and the color difference (ΔE) was calculated. The evaluation of the color difference (ΔE) is a color difference that can be distinguished by the system color name within the range of 13 to 25. If this range is exceeded, the color difference (ΔE) is determined by the Japan Color Research Institute. This is based on materials. Also, the color difference (ΔE) is calculated according to the following equation 1 based on materials from the Japan Color Research Institute. Note that ΔL *, Δa *, and Δb * in Equation 1 are the differences before and after the solvent immersion.

Table 1 will be used to examine Example 1 and Example 2, and Comparative Example 1 and Comparative Example 2. The evaluation criteria were as follows.
(Double-circle): The hue change of printed matter is remarkable.
○: Tendency to slightly change hue and print density of printed matter.
Δ: Hue change of printed matter is poor, and appearance equivalent to the level before immersion.

  As a result of measuring the color of the above-mentioned printed matter with an optical instrument, Example 1 was ΔE32.78 when immersed in acetone, and Δ39.06 when ethyl acetate was used. Also in Example 2, ΔE29.17 was obtained when immersed in acetone. Then, Δ36.03 was obtained, and a significant change in color difference was confirmed.

  On the other hand, the printed materials of Comparative Example 1 and Comparative Example 2 were not able to confirm a significant change in color difference due to optical equipment.

As a result of visual evaluation of the printed matter described above, it was confirmed that Example 1 changed from green to yellow within 5 seconds with acetone and ethyl acetate. Also in Example 2, it was confirmed that the hue of the printed material changed from black to orange within 5 seconds.

On the other hand, in Comparative Example 1, the hue change of the printed material was poor, and the appearance was the same as the level before immersion. Further, in Comparative Example 2, there was a tendency that a slight change in hue and print density of the printed material was observed, but there was no hue change that could be instantaneously discriminated.

Next, Examples 3 to 6 in which the color variable ink of the present invention is used as an ultraviolet curable ink will be described. Examples 3 to 5 are examples in which the color variable ink of the present invention was used as an ultraviolet curable offset ink. Example 6 is an example in which the color variable ink of the present invention was used as an ultraviolet curable intaglio ink.

The oil-soluble dyes are “trade name: MACROLEX Orange R (Lanxess Co., Ltd.), Plast blue 8510 (manufactured by Arimoto Chemical Co., Ltd.)” and “trade name: Plust Red 8320 (manufactured by Arimoto Chemical Industry Co., Ltd.) ) ”Was used. Note that “trade name: Oil Black DA-411” (manufactured by Arimoto Chemical Industry Co., Ltd.) is the same product as the above-described example, and therefore the description is omitted. The chemical structure and chemical name of the product “MACROLEX Orange R” described above is a methine dye, Disperse orange 47, the appearance is an orange powder, insoluble in water, and about 10% for ketones and ester solvents. Dissolve. The chemical structure and chemical name of “Plast blue 8510” is an anthraquinone dye, Solvent Blue 36, the appearance is blue powder, hardly soluble in water and ethanol, and 10% for ketone and ester solvents. It dissolves to a certain extent. The chemical structure and chemical name of “Plust Red 8320” is an anthraquininone-based dye, SolventRed 168, and its appearance is a red powder that is hardly soluble in water, methanol and butanol, and is soluble in MEK and xylene by 5.3%.

As the coloring pigment, a known pigment such as an azo pigment was used. As the varnish, a binder mainly composed of a monofunctional acrylate monomer or a bifunctional acrylate monomer was used. Moreover, the difference between Examples 3-5 and Example 6 is that Example 6 contains an extender, a desiccant, and a wax. Further, the decoloring in the present invention includes that the color disappears or the color almost disappears or the color changes to a light achromatic color. In addition, Example 5 is an example in which the color is almost lost by setting the color pigment to 1% by weight or less. If no color pigment is used, the color can be lost.

(Example 3)
[Composition of offset ink changing from UV curable brown to blue]
Orange oil-soluble dye 15% by weight
2% by weight of yellow pigment
3% by weight of blue pigment
Varnish 76% by weight
Photopolymerization initiator 4% by weight

Example 4
[Composition of offset ink changing from UV curable brown to red]
Blue oil-soluble dye 15% by weight
2% by weight of yellow pigment
3% by weight of red pigment
Varnish 76% by weight
Photopolymerization initiator 4% by weight

(Example 5)
[Composition of offset ink decolorizing from UV-curable brown]
Blue oil-soluble dye 10% by weight
Orange oil-soluble dye 10% by weight
Varnish 76% by weight
Photopolymerization initiator 4% by weight

(Example 6)
[Composition of intaglio ink that changes from UV-curable and oxidative polymerization combined type black to yellow]
Blue oil-soluble dye 10% by weight
Red oil-soluble dye 5% by weight
5% by weight of yellow pigment
Extender pigment 30% by weight
Varnish (1) 43.5% by weight
Varnish (2) 0.5% by weight
Photopolymerization initiator 3% by weight
1% by weight of desiccant
2% by weight of wax

In order to compare the change of the hue with respect to the solvent with the color variable ink of this invention, the composition of the ink of the comparative example 3 is illustrated. As the coloring pigment, known pigments such as phthalocyanine pigments and azo pigments were used. As the varnish, an acrylic resin was used. The auxiliary agent used contained water and isopropyl alcohol.

(Comparative Example 3)
[Composition of UV curable brown offset ink]
Orange pigment 15% by weight
2% by weight of yellow pigment
3% by weight of green pigment
Varnish (mainly polyfunctional acrylate) 76% by weight
Photopolymerization initiator 4% by weight

  Ink raw materials having the compositions of Examples 3 to 6 were kneaded by a three-roll mill kneader to produce each as an offset ink or an intaglio ink, and coated paper using an offset printing press or an intaglio printing press. Printed on. The aforementioned printed matter is immersed for 5 seconds using reagent-grade acetone (Wako Pure Chemical Industries, Ltd.) and reagent-grade ethyl acetate (Wako Pure Chemical Industries, Ltd.), and the hue change of the printed matter is visually and spectrophotometrically measured. The total was evaluated. Note that the evaluation standard and the spectrophotometer are the same as the printed matter using the water-based gravure ink, and are omitted.

  Using Table 2, Examples 3 to 6 and Comparative Example 3 will be verified.

As a result of measuring the color of the above-mentioned printed matter with an optical instrument, the color difference in Example 3 is ΔE50 to 55 for immersion with acetone, ΔE45 to 50 for ethyl acetate, ΔE35 to 40 for immersion in acetone in Example 4, and acetic acid. ΔE30 to 35 for ethyl, Example 5 is ΔE60 to 65 for immersion with acetone, ΔE55 to 60 for ethyl acetate, ΔE50 to 55 for immersion with acetone, ΔE50 to 55 for ethyl acetate, significant color difference The change was confirmed.

  On the other hand, in Comparative Example 3, a significant change in color difference could not be confirmed by an optical instrument.

As a result of visual evaluation of the printed matter, it was confirmed that Example 3 instantaneously changed the hue from brown to blue with acetone and ethyl acetate. Also in Example 4, the hue changed from brown to red instantly. In Example 5, the hue was instantaneously erased from brown. Also in Example 6, the hue changed from black to yellow instantaneously.

On the other hand, Comparative Example 3 had a color difference of ΔE5-7, so the hue change of the printed material was poor, and the appearance was equivalent to the level before immersion. Further, in Comparative Example 3, there was a tendency that a slight change in hue and print density of the printed material was observed, but there was no hue change that could be instantaneously discriminated.

Next, an example of a printed matter composed of a color variable region printed with the color variable ink of the present invention and a print region printed with a normal ink for comparison will be described with reference to the drawings. In this example, the ink prepared in the comparative example is used, but any known ink can be used as long as it does not contain an oil-soluble dye.

(Example 7)
FIG. 1 is a printed matter A1 in which a color variable region 2 using the aqueous gravure ink of Example 1 and a printing region 3 using the aqueous gravure ink of Comparative Example 2 are printed on the substrate 1. FIG. 1A is a plan view showing a state of the color variable region 2 and the print region 3 before acetone is applied to the printed matter A1. FIG. 1B is a plan view showing a state of the color variable region 2 ′ and the print region 3 after acetone is applied to the printed matter A <b> 1.

As shown in FIG. 1A, the printed matter A1 has a color variable area 2 made of green and a print area 3 made of black. On the other hand, as shown in FIG. 1B, after acetone was applied to the printed matter A1, it was confirmed that the hue changed from green to yellow like the color variable region 2 ′. Note that the hue of the print region 3 did not change.

(Example 8)
FIG. 2 shows a printed matter A2 in which the color variable region 4 by the ultraviolet curable ink of Example 3 and the printing region 5 by the ultraviolet curable ink of Comparative Example 3 are printed on the substrate 1. FIG. 2A is a plan view showing a state of the color variable region 4 and the print region 5 before acetone is applied to the printed matter A2. FIG. 2B is a plan view showing the state of the color variable region 4 ′ and the printing region 5 after acetone is applied to the printed material A <b> 2. Note that the colors of the color variable area 4 and the print area 5 are both brown before applying the solvent, that is, they are of the same color, so that the color variable area 4 and the print area 5 cannot be distinguished from each other. However, for convenience of explanation with the drawings, the color variable region 4 and the print region 5 are shown separately. In addition, although there is one color variable area in this embodiment, two or more color variable areas are printed using two or more types of color variable inks, and two or more color variable areas are equal to the print area. It can also be printed in color.

As shown in FIG. 2A, the printed matter A2 has a color variable area 4 made of brown and a print area 5 made of brown. As shown in FIG. 2B, it was confirmed that the hue changed from brown to blue as in the color variable region 4 ′ after acetone was applied to the printed matter A2. On the other hand, the hue of the printing area 5 did not change. Next, a printed material using two or more types of color variable ink will be described.

Example 9
FIG. 3 is a printed matter A3 in which the color variable region 6 with the ultraviolet curable ink of Example 4 and the color variable region 7 with the ultraviolet curable ink of Example 5 are printed on the substrate 1. FIG. 3A is a plan view showing a state of the color variable region 6 and the color variable region 7 before acetone is applied to the printed matter A2. FIG. 3B is a plan view showing a state of the color variable region 6 ′ and the color variable region 7 ′ after acetone is applied to the printed matter A3. Note that the colors of the color variable region 6 and the color variable region 7 are both brown before the solvent application, that is, the same color, so that the color variable region 6 and the color variable region 7 cannot be distinguished from each other. However, for convenience of description with the drawings, the color variable region 6 and the color variable region 7 are shown separately. In addition, the same color in the description of the present application means that it is difficult to distinguish hues in two or more regions with the naked eye, and includes not only the same color but also similar colors.

As shown in FIG. 3A, the printed matter A3 includes a color line 6 made of brown lines and numerals, and a color variable area 7 made of brown. As shown in FIG. 3B, it was confirmed that the hue changed from brown to red as in the color variable region 6 ′ after acetone was applied to the printed matter A3. On the other hand, it was confirmed that the hue of the color variable region 7 ′ almost disappeared.

Plan view showing printed matter A1 Plan view showing printed matter A2 Plan view showing printed matter A3

Explanation of symbols

A1, A2, A3 Printed matter 1 Base material 2 Color variable region (Green water-based gravure ink)
2 'Color change area after solvent application 3 Print area (black water-based gravure ink)
4 Color variable area (brown UV curable offset ink)
4 'Color change area after solvent application 5 Print area (Brown UV curable offset ink)
6 Color variable area (brown UV curable offset ink)
6 'Color change area after solvent application 7 Color change area (Brown UV-curing offset ink)
7 'Color change area after solvent application

Claims (6)

In an aqueous gravure ink containing a colorant in a water-soluble varnish obtained by neutralizing an acrylic resin containing a carboxyl group and / or a hydroxyl group with a volatile base, the colorant is 0.1 to 20% by weight of at least one kind. A water-insoluble and organic solvent-soluble oil-soluble dye and 1 to 20% by weight of a coloring pigment or not containing the coloring pigment, wherein the varnish contains an acrylic group containing a carboxyl group and / or a hydroxyl group A color variable ink containing 10 to 40% by weight of a resin and containing at least the colorant and the varnish. In the ultraviolet curable offset ink containing a colorant in a varnish mainly composed of a monofunctional group and / or a bifunctional acrylate monomer, the colorant is 5 to 20% by weight of at least one kind of water-insoluble and organic solvent. A solution-type oil-soluble dye and 5 to 20% by weight of a coloring pigment or not containing the coloring pigment, wherein the varnish contains 50 to 80% by weight of a monofunctional group and / or a bifunctional acrylate monomer. A color variable ink comprising: the colorant and the varnish. UV curable intaglio ink containing a varnish consisting of a UV-curable component obtained by carboxylating a monofunctional acrylate monomer containing a hydroxyl group with an acid anhydride, an oxidative polymerization component of an alkali-soluble alkyd resin, and an extender pigment The colorant is 10 to 20% by weight of at least one water-insoluble and organic solvent-soluble type oil-soluble dye and 5 to 20% by weight of a color pigment, and the extender is 20 to 45% by weight. The varnish contains 35-60% by weight of a monofunctional group and / or a bifunctional acrylate monomer and contains at least the colorant, the extender pigment, and the varnish. . A printed matter comprising at least one color variable region printed with the color variable ink according to any one of claims 1 to 3 on a base material. At least one first region and / or second region printed with at least one or more of the color variable inks, and at least one third region printed with an ink that does not contain an oil-soluble dye. 5. The printed matter having at least two types of print areas selected from the areas, wherein hues of at least two of the at least two types of print areas are equal in color. Prints. In the color variable region of the printed matter according to claim 4 and / or 5, the hue before applying or immersing the organic solvent and the hue after applying or immersing the organic solvent are based on the JIS color system. The printed matter according to claim 4, wherein the color difference is ΔE26 or more.

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