JP2020075981A - Ink and printed matter - Google Patents

Abstract

To provide an ink forming an image developing metallic color without no unevenness and with suppressed yellow tone.SOLUTION: There is provided an ink containing a silver particle with an average particle diameter of 100 nm or less, and a compound of the following general formula (1). In the general formula (1), n represents 1 or 2, Rto Rrepresent an alkyl group having 1 to 3 carbon atoms, Rrepresents hydrogen, halogen or an alkyl group having 1 to 3 carbon atoms, Yand Yrepresent an alkyl group having 1 to 6 carbon atoms, and Z represents a counter ion. Xand Xrepresent hydrogen, halogen, an alkyl group, or an alkoxy group, an aromatic ring may be condensed to other aromatic rings, and when it is condensed to other aromatic rings, the condensed aromatic ring has no substituent.SELECTED DRAWING: None

Description

  The present invention relates to an ink and a printed matter using the ink.

  In recent years, the uses of printed recording media (hereinafter, also referred to as recorded matter) have been diversified, and the recorded matter is used for a wide range of purposes such as office use and commercial use. With the diversification of applications, in addition to recorded matter represented by color materials of conventional colors such as cyan, magenta, yellow, and black, it is also represented by color materials having an unprecedented visual effect such as metallic luster. There is a demand for recorded materials.

  As the coloring material having metallic luster, it is preferable to use a silver coloring material because it can exhibit high gloss and high image clarity. By mixing the silver coloring material with a conventional coloring material, a recorded product having a full-color image with high image clarity can be obtained, so that the coloring material can be used for various purposes.

  Patent Document 1 discloses that another color is mixed with a silver colloid ink to obtain a toned metallic color.

  Patent Document 2 discloses that discoloration of an image is prevented by mixing a discoloration preventive agent with silver colloid ink.

However, mixing other colors with the silver ink causes unevenness. Further, since the discoloration preventing agent is not a coloring material, there is a problem that the glossiness is lowered and unevenness occurs.
It is an object of the present invention to provide an ink capable of forming an image that has no unevenness and exhibits a metallic color with suppressed yellowness.

一般式（１）において、ｎは１または２を表し、Ｒ₁、Ｒ₂、Ｒ₃およびＲ₄は炭素数１〜３のアルキル基を表し、Ｒ₅は、水素、ハロゲン、または炭素数１〜３のアルキル基を表し、Ｙ₁およびＹ₂は炭素数１〜６のアルキル基を表し、Ｚはカウンターイオンを表す。なお、Ｘ_１、Ｘ₂は水素、ハロゲン、アルキル基、またはアルコキシ基、を表す。また、芳香環は他の芳香環と縮合されていてもよく、他の芳香環と縮合されている場合は、縮合された芳香環は置換基を有しない。 In order to solve the problems described above, the present invention is as follows (1).
(1) An ink containing silver particles having an average particle size of 100 nm or less and a compound represented by the following general formula (1).

In the general formula (1), n represents 1 or 2, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₅ represents hydrogen, halogen, or 1 carbon atom. represents ~ 3 alkyl group, Y ₁ and Y ₂ represents an alkyl group having 1 to 6 carbon atoms, Z is represents a counter ion. Note that X ₁ and X ₂ represent hydrogen, halogen, an alkyl group, or an alkoxy group. Further, the aromatic ring may be condensed with another aromatic ring, and when the aromatic ring is condensed with another aromatic ring, the condensed aromatic ring does not have a substituent.

  The ink of the present invention can have a metallic color that is uniform and in which the yellow color of silver is moderated.

FIG. 1 is a perspective view illustrating an example of a recording device. FIG. 2 is a perspective explanatory view showing an example of the main tank.

一般式（１）において、ｎは１または２を表し、Ｒ₁、Ｒ₂、Ｒ₃およびＲ₄は炭素数１〜３のアルキル基を表し、Ｒ₅は、水素、ハロゲン、または炭素数１〜３のアルキル基を表し、Ｙ₁およびＹ₂は炭素数１〜６のアルキル基を表し、Ｚはカウンターイオンを表す。なお、Ｘ_１、Ｘ₂は水素、ハロゲン、アルキル基、またはアルコキシ基、を表す。また、芳香環は他の芳香環と縮合されていてもよく、他の芳香環と縮合されている場合は、縮合された芳香環は置換基を有しない。
（５） 前記印刷層が、平均粒径が１０ｎｍ以上３０ｎｍ以下である樹脂粒子を含有する前記（４）に記載の印刷物。 Hereinafter, embodiments of the present invention will be described.
Although the embodiment of the present invention relates to the above (1), the following (2) to (5) are also included as embodiments.
(2) The ink according to (1), which contains the compound represented by the general formula (1) in an amount of 0.01% by mass or more and 0.5% by mass or less based on the total amount of the ink.
(3) The ink according to (1) or (2) above, which contains resin particles having an average particle size of 10 nm or more and 30 nm or less.
(4) A printed matter having a printed layer containing silver particles having an average particle diameter of 100 nm or less and a compound represented by the following general formula (1).

In the general formula (1), n represents 1 or 2, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₅ represents hydrogen, halogen, or 1 carbon atom. represents ~ 3 alkyl group, Y ₁ and Y ₂ represents an alkyl group having 1 to 6 carbon atoms, Z is represents a counter ion. Note that X ₁ and X ₂ represent hydrogen, halogen, an alkyl group, or an alkoxy group. Further, the aromatic ring may be condensed with another aromatic ring, and when the aromatic ring is condensed with another aromatic ring, the condensed aromatic ring does not have a substituent.
(5) The printed matter according to (4), wherein the printed layer contains resin particles having an average particle size of 10 nm or more and 30 nm or less.

<< Ink >>
The ink of the present invention contains silver particles having an average particle diameter of 100 nm or less, the compound represented by the general formula (1), and may contain other components. Hereinafter, the ink of the present invention is also referred to as a silver ink or a silver ink.

<Silver particles>
The ink of the present invention contains silver particles. Silver is a metal with high whiteness among various metals, and is preferable because it can realize various metal colors by combining with a color material of another color or an ink containing a color material of another color. Further, silver has low reactivity with water and is stable in water. As a result, it is preferable because it can be applied to a water-based glitter ink that can reduce environmental load.

The average particle size of the silver particles is 100 nm or less, preferably 50 nm or less, more preferably 5 nm or more and 50 nm or less. When the thickness is 100 nm or less, an image showing high dispersion stability in ink, excellent glossiness and image clarity can be obtained. However, when an image is formed by using silver particles having a particle size of 100 nm or less, there is a problem that a metallic color including yellowishness is obtained. In the present invention, by containing the compound represented by the general formula (1), it is possible to provide an image exhibiting a metallic color with suppressed yellowness. When a pigment other than the compound represented by the general formula (1) is contained, the ink containing silver of 100 nm or less loses metallic luster. Further, when a dye other than the compound represented by the general formula (1) is used, a large amount needs to be added to suppress the yellowness, and if the amount necessary for suppressing the yellowness is included, the metallic luster is lost. Be seen.
To measure the average particle size of silver particles in the dispersion or the ink, first, several μl of the dispersion or the ink is sampled and a frozen body is prepared by the high pressure freezing method. After cleaving the frozen body, a carbon replica film having a cross section is produced. The replica film is placed on a grid for a transmission microscope (TEM), observed with a TEM, the major axis of silver particles in a TEM image in the range of 5 μm × 5 μm is measured, and the average thereof is calculated to obtain the average particle size.

  The content of silver particles in the ink is preferably 1.0% by mass or more and 15.0% by mass or less, and more preferably 2.0% by mass or more and 13% by mass or less, based on the total amount of the ink. When the content is 1.0% by mass or more, the image clarity of the print layer formed on the recording medium using the ink is improved, which is preferable. Further, when the content is 15.0% by mass or less, dispersion stability and storage stability of silver particles in the ink are improved, and ejection stability is excellent when the ink is ejected by an inkjet method, which is preferable. .

-Dispersion form of silver particles-
The silver particles are preferably dispersed in an aqueous dispersion medium as a silver colloid having a protective colloid attached to the surface. As a result, the dispersibility of the silver particles in the aqueous dispersion medium becomes excellent, and the storage stability of the ink is improved. The silver colloid may be prepared by any method and can be obtained, for example, by preparing a solution containing silver ions and reducing the silver ions with a reducing agent in the presence of a protective colloid. (For example, refer to JP-A-2006-299329). When a silver colloid is produced by these methods, if a surfactant or the like is added to the aqueous solution at any point before and after the reduction reaction, the dispersion stability of the metal particles is further improved. The protective colloid is not particularly limited as long as it is an organic substance that protects the surface of the silver particles, but an organic compound having a carboxyl group and a polymer dispersant are preferable, and either one may be used alone or used in combination. However, it is more preferable to use them together because they have a synergistic effect. Further, for silver particles of large size, a silver colloid obtained by the method described in Japanese Patent No. 5059317 or Japanese Patent No. 6180769 can be used.

--- Organic compound having a carboxyl group ---
The organic compound having a carboxyl group includes carboxylic acid. The carboxylic acid is not particularly limited as long as it can coat the silver particles, and examples thereof include monocarboxylic acids such as aliphatic monocarboxylic acids and aromatic monocarboxylic acids, aliphatic polycarboxylic acids and aromatic polycarboxylic acids, and the like. Examples thereof include hydroxycarboxylic acids (or oxycarboxylic acids) such as polycarboxylic acids, hydroxymonocarboxylic acids and hydroxypolycarboxylic acids.
Among these organic compounds having a carboxyl group, hydroxycarboxylic acids such as aliphatic hydroxycarboxylic acids (aliphatic hydroxymonocarboxylic acid and aliphatic hydroxypolycarboxylic acid) are preferable, and among aliphatic hydroxycarboxylic acids, further Cyclic hydroxycarboxylic acid (or hydroxycarboxylic acid having an alicyclic skeleton, for example, C6-34 alicyclic hydroxycarboxylic acid such as cholic acid, preferably C10-34 alicyclic hydroxycarboxylic acid, more preferably C16- 30 alicyclic hydroxycarboxylic acids) are preferred.
In particular, polycyclic aliphatic hydroxycarboxylic acid such as cholic acid is preferable because it has a bulky structure and has a great effect of suppressing aggregation of silver particles.

  In addition, these carboxylic acids may form a salt, and may be an anhydride, a hydrate or the like. The carboxylic acid is preferably an organic compound that does not form a salt (particularly, a salt with a basic compound such as a salt with an amine). The organic compounds having a carboxyl group may be used alone or in combination of two or more.

  The molecular weight of the organic compound having a carboxyl group is, for example, preferably 1000 or less, more preferably 800 or less, and further preferably 600 or less. Further, the pKa value of the organic compound having a carboxyl group is, for example, preferably 1 or more, and more preferably 2 or more.

--- Polymer dispersant ---
The polymer dispersant is not particularly limited as long as it can coat silver particles, but an amphipathic polymer dispersant (or oligomer-type dispersant) can be preferably used. Examples of the polymer dispersant include polymer dispersants which are generally used for dispersing colorants in the fields of paints and inks. Such dispersants include styrene resins (styrene- (meth) acrylic acid copolymer, styrene-maleic anhydride copolymer, etc.), acrylic resins (methyl (meth) acrylate- (meth) acrylic acid). Copolymer, etc.), water-soluble urethane resin, water-soluble acrylic urethane resin, water-soluble epoxy resin, water-soluble polyester resin, cellulose derivative (alkyl cellulose such as ethyl cellulose, alkyl-hydroxyalkyl cellulose such as ethyl hydroxyethyl cellulose, hydroxyethyl cellulose) , Hydroxyalkyl cellulose such as hydroxypropyl cellulose, carboxyalkyl cellulose such as carboxymethyl cellulose), polyvinyl alcohol, polyalkylene glycol (liquid polyethylene glycol, polypropylene glycol, etc.), natural polymer (gelatin, dextrin, etc.), polyethylene sulfonic acid For example, salts and formalin condensates of naphthalene sulfonic acid are included. Representative polymer dispersants (amphiphilic polymer dispersants) include resins (water-soluble resins or water-dispersible resins) containing a hydrophilic unit composed of a hydrophilic monomer.

  The polymer dispersant may have a functional group. Examples of such a functional group include an acid group (or an acidic group, for example, a carboxyl group (or an acid anhydride group), a sulfo group (a sulfonic acid group and the like), a hydroxyl group, and the like. Of these functional groups, the polymer dispersant preferably has an acid group, particularly a carboxyl group, alone or in combination of two or more.

  When the polymer dispersant has an acid group (such as a carboxyl group), at least a part or all of the acid group (such as a carboxyl group) forms a salt (a salt with an amine, a metal salt, etc.). You may have. However, in the present invention, a polymer dispersant in which an acid group such as a carboxyl group does not form a salt (particularly, a salt with a basic compound) can be preferably used.

  The number average molecular weight of the polymer dispersant is preferably from 1,500 to 100,000, more preferably from 2,000 to 80,000, still more preferably from 3,000 to 50,000, particularly preferably from 7,000 to 20,000.

Specific examples of commercially available polymer dispersants (or dispersants composed of at least amphipathic dispersants) are Solsperse 13240, Solsperse 13940, Solsperse 32550, Solsperse 31845, Solsperse 24000, Solsperse 26000, Sols Perth series such as Sols Perth 27000, Sols Perth 28000, Sols Perth 41090 [manufactured by Avicia Co., Ltd.]; Disperbic 160, Disperbic 161, Disperbic 162, Disperbic 163, Disperbic 164, Disperbic 166, Disperbic 170, Disper Disperbic series such as Bic180, Disperbic182, Disperbic184, Disperbic190, Disperbic191, Disperbic192, Disperbic193, Disperbic194, Disperbic2001, Disperbic2050 [manufactured by Big Chemie Co., Ltd.] EFKA-46, EFKA-47, EFKA-48, EFKA-49, EFKA-1501, EFKA-1502, EFKA-4540, EFKA-4550, polymer 100, polymer 120, polymer 150, polymer 400, polymer 401, polymer 402; , Polymer 403, Polymer 450, Polymer 451, Polymer 452, Polymer 453 [manufactured by EFKA Chemical Co., Ltd.]; Azisper PB711, Azispar PAl11, Azisper PB811, Azisper PB821, Azisper PW911, etc. Azisper series [Ajinomoto Co., Inc.] Fullerene series such as fullerene DOPA-158, fullerene DOPA-22, fullerene DOPA-17, fullerene TG-700, fullerene TG-720W, fullerene-730W, fullerene-740W, fullerene-745W [manufactured by Kyoeisha Chemical Co., Ltd.]; Examples thereof include John Krill 678, John Krill 679, and John Krill 62, and other John Krill series (manufactured by Johnson Polymer Co., Ltd.).
Among these, Disperbic 190 and Disperbic 194, which are polymer dispersants having an acid group, are preferable.

一般式（１）において、ｎは１または２を表し、Ｒ₁、Ｒ₂、Ｒ₃およびＲ₄は炭素数１〜３のアルキル基を表し、Ｒ₅は、水素、ハロゲン、または炭素数１〜３のアルキル基を表し、Ｙ₁およびＹ₂は炭素数１〜６のアルキル基を表し、Ｚはカウンターイオンを表す。なお、Ｘ_１、Ｘ₂は水素、ハロゲン、アルキル基、またはアルコキシ基、を表す。また、芳香環は他の芳香環と縮合されていてもよく、他の芳香環と縮合されている場合は、縮合された芳香環は置換基を有しない。
前記Ｙ₁およびＹ₂の炭素数１〜６のアルキル基は、置換あるいは未置換のアルキル基であり、ハロゲンやアルコキシ基で置換されていても良い。
Ｘ_１、Ｘ₂のアルキル基、アルコキシ基としては、炭素数１〜４であることが好ましい。 <Compound represented by the general formula (1)>
By containing the compound represented by the following general formula (1) in the ink of the present invention, the desired chromaticity can be improved. The dye having the structure of the general formula (1) has a high light absorption ability, and an effect can be obtained with a small addition amount, and the content is 0.001% by mass or more and 10% by mass or less based on the total amount of the ink. It is preferable that the content is 0.005% by mass or more and 5% by mass or less, more preferably 0.01% by mass or more and 0.5% by mass or less.

In the general formula (1), n represents 1 or 2, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₅ represents hydrogen, halogen, or 1 carbon atom. represents ~ 3 alkyl group, Y ₁ and Y ₂ represents an alkyl group having 1 to 6 carbon atoms, Z is represents a counter ion. Note that X ₁ and X ₂ represent hydrogen, halogen, an alkyl group, or an alkoxy group. Further, the aromatic ring may be condensed with another aromatic ring, and when the aromatic ring is condensed with another aromatic ring, the condensed aromatic ring does not have a substituent.
The alkyl group having 1 to 6 carbon atoms of Y ₁ and Y ₂ is a substituted or unsubstituted alkyl group, and may be substituted with a halogen or an alkoxy group.
The alkyl group and alkoxy group of X ₁ and X ₂ preferably have 1 to 4 carbon atoms.

  Z represents a counter ion, specifically, a halogen ion, a phosphate ion, a hexafluorophosphate ion, a perchlorate ion, a periodate ion, a hexafluoroantimonate ion, a hexafluorostannate ion, and a borofluoride. Inorganic acid ions such as hydrogen hydride ion and tetrafluoroborate ion, thiocyanate ion, benzenesulfonate ion, naphthalenesulfonate ion, p-toluenesulfonate ion, alkylsulfonate ion, benzenecarboxylate ion, alkylcarboxylate Organic acid ions such as acid ions, trihaloalkylcarboxylate ions, alkylsulfate ions, trihaloalkylsulfate ions, and nicotinate ions, as well as azo-based, bisphenyldithiol-based, thiocatechol chelate-based, thiobisphenolate chelate-based, A bisdiol-α-diketone-based metal complex ion or the like is adopted.

Examples of the compound represented by the general formula (1) include, but are not limited to, the compounds shown below.

  Other components contained in the ink of the present invention include organic solvents, water, resins, additives and the like, and as the additives, surfactants, defoaming agents, antiseptic and antifungal agents, rust preventive agents. , PH adjusters and the like.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of the polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Examples include 1,3-pentanediol and petriol.
Examples of polyhydric alcohol alkyl ethers include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam and γ-butyrolactone. Can be mentioned.
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide and the like.
Examples of amines include monoethanolamine, diethanolamine, triethylamine and the like.
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol and the like.
Examples of other organic solvents include propylene carbonate and ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or less because it not only functions as a wetting agent but also obtains good drying properties.

As the organic solvent, a polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and the like.

  Further, examples of the organic solvent also include oxetane compounds such as 3-ethyl-3-hydroxymethyloxetane.

<Water>
The content of water in the ink is not particularly limited and can be appropriately selected according to the purpose, but from the viewpoint of the drying property of the ink and the ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % Or more and 60 mass% or less is more preferable.

<Resin>
The silver ink of the present invention need not contain a resin, but preferably contains a resin, and the printing layer formed on the recording medium using the resin-containing ink has a stable structure in which silver particles are spread without agglomeration. It can be maintained for a long time, and even if silver particles aggregate, the area where they aggregate can be reduced. Therefore, when the recorded matter is stored at high temperature for a long time, it is the chromaticity (color value) of the image. It is excellent in that the b ^* value does not change significantly.
The resin is preferably a water-soluble resin soluble in water or a water-dispersible resin dispersible in water, and may be used alone or in combination.

-Water-soluble resin-
The water-soluble resin is not particularly limited, and examples thereof include proteins such as gelatin and casein, natural gums such as gum arabic, glucoxides such as savonine, cellulose derivatives such as methylcellulose, carboxymethylcellulose and hydroxymethylcellulose, and ligninsulfonic acid. Natural polymers such as salts and shellac, polyacrylic acid salts, polyacrylamides, styrene-acrylic acid copolymer salts, vinylnaphthalene-acrylic acid copolymer salts, styrene-maleic acid copolymer salts, vinylnaphthalene-maleic acid Copolymer salt, sodium salt of β-naphthalenesulfonic acid formalin condensate, ionic polymer such as polyphosphoric acid, polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, polypropylene glycol, polyethylene oxide, polyvinyl methyl ether, polyethyleneimine and the like. Be done. As the water-soluble resin, those appropriately synthesized may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of water-soluble resins.

-Water dispersible resin-
The water dispersible resin is not particularly limited, and examples thereof include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin. , Acrylic styrene resin, acrylic silicone resin, and the like. You may use the resin particle which consists of these resins. Ink can be obtained by mixing resin particles in a state of a resin emulsion in which water is used as a dispersion medium, with a material such as silver particles or an organic solvent. As the water-dispersible resin, a properly synthesized resin may be used, or a commercially available product may be used. These may be used alone or in combination of two or more kinds of water-dispersible resins.

The average particle size of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 nm or more and 30 nm or less from the viewpoint of obtaining good image clarity and glossiness. A printing layer formed on a recording medium using an ink containing resin particles having an average particle diameter of 10 nm or more and 30 nm or less can stably maintain a structure in which silver particles are spread without agglomerating. Even if the silver particles are aggregated, the area where they are aggregated can be reduced, so that it is excellent in that the b ^* value, which is the chromaticity (color value) of the image, does not change significantly when the recorded matter is stored at high temperature for a long time. ..
The average particle size of the resin particles in the ink can be measured, for example, as follows. First, several μl of ink is collected and a frozen body is prepared by the high pressure freezing method. After cleaving the frozen body, a carbon replica film having a cross section is produced. The replica film is placed on a TEM grid, observed by TEM, the major axis of the resin particles in the TEM image in the range of 5 μm × 5 μm is measured, and the average thereof is determined as the average particle diameter of the resin particles.

  The content of the resin is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoint of good scratch resistance, image clarity and metallic luster, 0.01% by mass relative to the total amount of the ink is used. The above is preferable, 0.05 mass% or more is more preferable, and 0.3 mass% or more is further preferable. Further, it is preferably 10.0% by mass or less, more preferably 4.0% by mass or less, further preferably 2.0% by mass or less.

  The mass ratio (resin / silver particles) of the content of the resin in the ink to the content of the silver particles in the ink is preferably 0.001 or more and 0.2 or less, more preferably 0.01 or more and 0.1 or less. preferable.

<Surfactant>
The ink of the present invention preferably contains a surfactant, and the following can be used as an example.

（但し、一般式（Ｓ−１）式中、ｍ、ｎ、ａ、及びｂは、それぞれ独立に、整数を表わし、Ｒは、アルキレン基を表し、Ｒ’は、アルキル基を表す。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ−６１８、ＫＦ−６４２、ＫＦ−６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ−ＳＳ−５６０２、ＳＳ−１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ−２１０５、ＦＺ−２１１８、ＦＺ−２１５４、ＦＺ−２１６１、ＦＺ−２１６２、ＦＺ−２１６３、ＦＺ−２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ−３３、ＢＹＫ−３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and side-chain. Examples thereof include both-end modified polydimethylsiloxane, etc., and a polyether modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group is particularly preferable because it shows good properties as an aqueous surfactant. .
As such a surfactant, those synthesized appropriately may be used, or commercially available products may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Kagaku, etc.
The polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the polyalkylene oxide structure represented by the general formula (S-1) is represented by dimethylpolyethylene. Examples thereof include those introduced into the side chain of the Si part of siloxane.

(However, in the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R ′ represents an alkyl group.)
As the above polyether-modified silicone-based surfactant, commercially available products can be used, for example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-. 1906EX (Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

  The content of the silicone surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.001% by mass or more and 5.0% by mass or less, and 0.05% by mass or less. % Or more and 5.0% by mass or less is more preferable, and 0.5% by mass or more and 1.0% by mass or less is further preferable.

Examples of the fluorinated surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphoric acid ester compound, a perfluoroalkyl ethylene oxide adduct and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salts. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in its side chain include a sulfuric acid ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in its side chain and a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in its side chain. Examples thereof include salts of oxyalkylene ether polymers. The counterions of the salts in these fluorine-based surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH). ₃ etc.

  Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.

  Examples of the nonionic surfactants include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan. Examples thereof include fatty acid esters and ethylene oxide adducts of acetylene alcohol.

  Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl acid salt, and salt of polyoxyethylene alkyl ether sulfate.

  The content of the surfactant in the ink is appropriately selected depending on the intended purpose without any limitation, but it is 0.001 mass% from the viewpoint of excellent wettability and ejection stability and improving image quality. % Or more and 5 mass% or less is preferable, and 0.05 mass% or more and 5 mass% or less is more preferable.

<Antifoam>
The defoaming agent is not particularly limited, and examples thereof include a silicone defoaming agent, a polyether defoaming agent, and a fatty acid ester defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because of its excellent foam breaking effect.

<Antiseptic and fungicide>
The antiseptic / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
The rust preventive agent is not particularly limited, and examples thereof include acid sulfite and sodium thiosulfate.

<PH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

<Physical properties of ink>
The physical properties of the ink are not particularly limited and may be appropriately selected depending on the purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, from the viewpoint that the printing density and character quality are improved and good ejection properties are obtained, and 5 mPa · s or more and 25 mPa · s or less are preferable. More preferable. Here, as the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. The measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less, and more preferably 32 mN / m or less at 25 ° C., since the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12, and more preferably 8 to 11 from the viewpoint of preventing the corrosion of the metal member with which the ink comes into contact.

<< Recording medium >>
In the printing method of the present invention, a glossy paper having a receiving layer on its surface or a non-permeable substrate may be used. The receiving layer (porous or the like) may or may not be previously formed on the surface of the recording medium. The recording medium is not limited to those generally used as a recording medium, and wallpaper, flooring, building materials such as tiles, cloths for clothing such as T-shirts, textiles, leather and the like can be appropriately used. .. Further, ceramics, glass, metal or the like can be used by adjusting the configuration of the path for conveying the recording medium.

The non-permeable base material is a base material having a surface having low water permeability and absorbability, and includes a material that does not open to the outside even if there are many cavities inside, and more quantitatively, In the Bristow method, it refers to a substrate having a water absorption amount of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 . As the impermeable substrate, for example, a plastic film such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, polypropylene, polyethylene, a polycarbonate film can be preferably used.

  A commercially available product can be used as the recording medium having a receiving layer having a receiving layer (porous) in advance. Examples of commercially available products include IJ film RM-1GP01 (manufactured by Ricoh Co., Ltd., porous average pore size: 230 nm), NB-WF-3GF100 (porous average pore size: 210 nm), NB-RC-3GR120 (porous). Quality average pore diameter: 250 nm) (manufactured by Mitsubishi Paper Mills Ltd.) PT-201A420 (porous average pore diameter: 270 nm), SD-101A450 (porous average pore diameter: 250 nm), GL-101A450 (porous average pore diameter: 240 nm), GP501A450 (porous average pore diameter: 250 nm), SP-101A450 (porous average pore diameter: 210 nm), PT-101A420 (porous average pore diameter: 240 nm), PR101 (porous average pore diameter: 270 nm). (Manufactured by Canon Inc.), EJK-QTNA450 (porous average pore size: 200 nm), EJK-EPNA450 (porous average pore size: 210 nm), EJK-CPNA450 (porous average pore size: 220 nm), EJK-RCA450 (porous average pore size: 220 nm). Porous average pore diameter: 240 nm), EJK-CGNA450 (porous average pore diameter: 190 nm), EJK-GANA450 (porous average pore diameter: 180 nm), EJK-NANA450 (porous average pore diameter: 170 nm), EJK- EGNA450 (porous average pore diameter: 200 nm) (manufactured by Elecom Co., Ltd.), WPA455VA (porous average pore diameter: 200 nm), WPA450PRM (porous average pore diameter: 210 nm), G3A450A (porous average pore diameter: 220 nm), G3A450A (porous average pore diameter: 210 nm), WPA420HIC (porous average pore diameter: 280 nm) (manufactured by FUJIFILM Corporation), KA420SCKR (porous average pore diameter: 240 nm), KA450PSKR (porous average pore diameter: 230 nm). , KA450SLU (porous average pore diameter: 210 nm) (manufactured by Seiko Epson Corporation), BP71GAA4 (porous average pore diameter: 220 nm) (manufactured by Brother Industries, Ltd.) and the like.

<< Recording device, recording method >>
The ink of the present invention can be suitably used for various recording devices based on the inkjet recording system, such as printers, facsimile devices, copying devices, printer / fax / copier compound machines, and three-dimensional modeling devices.
In the present invention, the recording device and the recording method are a device capable of ejecting ink, various treatment liquids and the like onto a recording medium, and a method of recording using the device. The recording medium means a medium to which ink or various treatment liquids can be attached even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means for feeding, conveying, and discharging a recording medium, and other devices such as a pre-processing device and a post-processing device. .
The recording device and the recording method may have a heating means used in the heating step and a drying means used in the drying step. The heating means and the drying means include, for example, means for heating and drying the printing surface or the back surface of the recording medium. The heating means and the drying means are not particularly limited, but, for example, a warm air heater or an infrared heater can be used. The heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording device and the recording method are not limited to those in which a significant image such as a character or a figure is visualized by ink. For example, the thing which forms patterns, such as a geometric pattern, and the thing which models a three-dimensional image are also included.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise limited.
Further, this recording device is not limited to a desktop type, and can be used as a wide recording device capable of printing on an A0 size recording medium, or for example, continuous paper wound in a roll shape as a recording medium. It also includes a continuous form printer.
An example of the recording device will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanism section 420 is provided inside the exterior 401 of the image forming apparatus 400. Each ink containing portion 411 of the main tank 410 (410s, 410c, 410m, 410y) for each color of silver (S), cyan (C), magenta (M), and yellow (Y) is packed with, for example, an aluminum laminate film. It is formed of a member. The ink container 411 is housed in a container case 414 made of plastics, for example. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus main body is opened. The main tank 410 is detachably attached to the cartridge holder 404. As a result, the ink discharge ports 413 of the main tank 410 and the ejection heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and ink can be ejected from the ejection heads 434 to the recording medium.
The silver (S) ink is the ink of the present invention. The color inks of cyan (C), magenta (M), and yellow (Y) are not particularly limited, and known inks can be appropriately selected according to the purpose. In addition to the above three colors other than silver (S), inks such as black (K) and white (W) may be additionally used. When the additional ink is used, a liquid container having the additional ink and a liquid ejection head are added to the recording device. By applying the ink containing the coloring material other than silver to the position on the recording medium to which the silver ink of the present invention is applied, colors having various metallic lusters other than silver can be reproduced.

This recording device can include not only a part for ejecting ink, but also a device called a pre-processing device, a post-processing device, or the like.
As one mode of the pretreatment device and the posttreatment device, as in the case of inks such as silver (S), cyan (C), magenta (M), and yellow (Y), a pretreatment liquid and a posttreatment liquid are included. There is a mode in which a liquid storage section and a liquid ejection head are added and a pretreatment liquid and a posttreatment liquid are ejected by an inkjet recording method.
As another aspect of the pretreatment apparatus and the posttreatment apparatus, there is an aspect in which a pretreatment apparatus and a posttreatment apparatus other than the inkjet recording method, for example, a blade coating method, a roll coating method, and a spray coating method are provided.

  The method of using the ink is not limited to the ink jet recording method and can be widely used. In addition to the inkjet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

<Printed matter>
The printed material of the present invention has a silver particle having an average particle diameter of 100 nm or less and a printed layer containing the compound represented by the general formula (1). It can be obtained by printing using the ink of the present invention.

  The printed layer preferably contains a resin. When the printed layer contains a resin, the image clarity and scratch resistance of the printed layer can be further improved. The content of the resin in the printing layer is preferably 0.01% by mass or more and 5.0% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the total amount of the printing layer. When the content is 0.01% by mass or more and 5.0% by mass or less, the image clarity, metallic luster and scratch resistance of the printed layer are improved. The resin contained in the printed layer is preferably resin particles having an average particle size of 10 nm or more and 30 nm or less.

-Layer thickness and particle size of the silver ink print layer-
The layer thickness of the silver ink print layer is preferably 50 nm or more and 300 nm or less, more preferably 50 nm or more and 250 nm or less, further preferably 50 nm or more and 200 nm or less, and particularly preferably 50 nm or more and 180 nm or less. preferable. When the thickness of the printing layer is within this range, the structural color tone derived from the plasmon absorption of the silver particles becomes low, and the printing layer excellent in metallic luster and image clarity can be formed. When the amount of ink applied is such that the thickness of the printing layer is within this range, the vehicle of the ink can be immediately absorbed when the recording medium has a porous structure, and printing with excellent metallic luster and image clarity is possible. Layers can be formed. Moreover, the layer thickness of the printing layer is required to be at least one silver particle or more. By arranging one or more layers of silver particles in the lateral direction on the recording medium, the interaction between silver particles is increased, and it is possible to form a printing layer excellent in metal-like image clarity. The print layer whose layer thickness is measured is a layer after the ink applied to the recording medium is sufficiently dried. The layer thickness of the printed layer is an average value of the layer thicknesses obtained by measuring 10 points at arbitrary points of the printed layer. Examples of the method of measuring the layer thickness of the printed layer include a method of cutting a recorded material and observing the cut surface with a microscope such as an optical microscope, a laser microscope, an SEM, or a TEM.
Further, the particle size of silver and the resin particle size on the print medium can be measured by observing and analyzing with a TEM.
For the average particle diameter and the resin particle diameter of the silver particles in the printed layer, the major axis of the silver particles and the resin particles in the TEM image in the range of 10 μm × 10 μm is measured, and the average thereof is determined to be the average particle diameter. When it is impossible to measure with TEM, SEM can be used instead.

-B ^* value of printing layer-
The b ^* value of the printed layer is based on the color difference display method by the L ^* a ^* b ^* color system standardized by CIE (Commission International de l'Eclairage). In order for the print layer to have a high image clarity and to be silvery, the b ^* value is preferably -7 to 0. As for the b ^* value, the blueness becomes stronger toward the negative side, and conversely, the yellowness becomes stronger toward the positive side. When the yellow color becomes strong, the printed layer approaches a gold color, and when the b ^* value exceeds 0, the gold color is strongly developed and the color tone is hard to be said to be silver. On the other hand, when the b ^* value is less than -7, the bluish tint becomes stronger and the tone becomes darker than that of silver. The b ^* value can be easily measured with a spectrocolorimeter.

<Color ink print layer>
The recorded matter may further have a color ink print layer formed on the print layer formed on the recording medium. The color ink print layer is a layer formed by applying an ink containing a coloring material other than silver particles and containing a coloring material other than silver particles.
The average thickness of the color ink print layer is preferably 1 nm or more and 300 nm or less, more preferably 2 nm or more and 250 nm or less. When the silver color of the print layer is toned, it is necessary not to hide the silver color, and the average thickness at that time is preferably 3 nm or more and 100 nm or less. When the average thickness of the color ink print layer is adjusted within the above range, a colored metallic image is obtained, and a recorded matter having good texture and color tone can be obtained. Regarding the order of toning, it is preferable to form a print layer with the ink of the present invention and then form a color ink print layer on the print layer. Examples of the method for measuring the layer thickness of the color ink print layer include a method of cutting a recorded material and observing the cut surface with a microscope such as an optical microscope, a laser microscope, an SEM, and a TEM.

<< Application >>
The use of the ink of the present invention is not particularly limited and can be appropriately selected according to the purpose. For example, the ink can be applied to printed matter, paints, coating materials, bases and the like. Further, it can be used not only as a two-dimensional character or image by using as ink, but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional model).
As a three-dimensional modeling device for modeling a three-dimensional molded object, a known one can be used and is not particularly limited. For example, a device provided with an ink containing means, a supplying means, a discharging means, a drying means, etc. is used. be able to. The three-dimensional molded object includes a three-dimensional molded object obtained by overcoating with ink. Further, it also includes a molded product obtained by processing a structure to which ink is applied on a substrate such as a recording medium. The molded product is, for example, a recording product or a structure formed in a sheet shape or a film shape, which is subjected to molding processing such as heat drawing and punching processing, and is, for example, an automobile, an OA device, an electric It is suitably used for applications such as electronic devices, meters for cameras, panels for operation parts, and the like, after the surface is decorated.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Preparation example 1 of resin dispersion containing resin particles)
<Preparation of Polyester Urethane Resin Dispersion 1>
200.4 g of polyester polyol (trade name: PTMG1000, manufactured by Mitsubishi Chemical Corporation, average molecular weight: 1,000) in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer -Dimethylolpropionic acid 15.7 g, isophorone diisocyanate 48.0 g, and methyl ethyl ketone 77.1 g as an organic solvent were reacted using 0.06 g of dibutyltin dilaurate (DMTDL, manufactured by Tokyo Chemical Industry Co., Ltd.) as a catalyst. After the reaction was continued for 4 hours, 30.7 g of methyl ethyl ketone was supplied as a diluting solvent, and the reaction was further continued. After performing the reaction for a total of 6 hours, 1.4 g of methanol was added and the reaction was terminated to obtain an organic solvent solution of urethane resin. By adding 13.4 g of 48 mass% potassium hydroxide aqueous solution to the organic solvent solution of the urethane resin, the carboxyl groups possessed by the urethane resin are neutralized, and then 715.3 g of water is added and sufficiently stirred, By aging and desolvation, a polyester urethane resin dispersion liquid 1 containing resin particles having a solid content concentration of 30 mass% was obtained.

(Preparation example 2 of resin dispersion containing resin particles)
<Preparation of Polyester Urethane Resin Dispersion 2>
In Preparation Example 1 of resin dispersion liquid containing resin particles, except that the content of DMTDL was changed from 0.06 g to 0.12 g and the total reaction time was changed to 15 hours, Similarly, a polyester urethane resin dispersion liquid 2 containing resin particles having a solid content concentration of 30 mass% was obtained.

(Preparation Example 3 of resin dispersion containing resin particles)
<Preparation of Polyester Urethane Resin Dispersion 3>
In Preparation Example 1 of resin dispersion liquid containing resin particles, the same as Preparation Example 1 of resin dispersion liquid containing resin particles except that the content of DMTDL was changed from 0.06 g to 0.2 g and the total reaction time was changed to 8 hours. Then, a polyester urethane resin dispersion liquid 3 containing resin particles having a solid content concentration of 30 mass% was obtained.

(Preparation Example 4 of resin dispersion containing resin particles)
<Preparation of Polyester Urethane Resin Dispersion Liquid 4>
In Preparation Example 1 of resin dispersion liquid containing resin particles, the same procedure as in Preparation Example 1 of resin dispersion liquid containing resin particles except that 0.06 g of DMTDL content was changed to 0.2 g and the reaction time was changed to 5 hours. Thus, a polyester urethane resin dispersion liquid 4 containing resin particles having a solid content concentration of 30 mass% was obtained.

(Preparation Example 5 of resin dispersion containing resin particles)
<Preparation of Polyester Urethane Resin Dispersion 5>
In Preparation Example 1 of resin dispersion liquid containing resin particles, the same procedure as in Preparation Example 1 of resin dispersion liquid containing resin particles except that the content of DMTDL was changed from 0.06 g to 0.12 g and the reaction time was changed to 10 hours. Thus, a polyester urethane resin dispersion liquid 5 containing resin particles having a solid content concentration of 30 mass% was obtained.

(Preparation Example 6 of resin dispersion containing resin particles)
<Preparation of Polycarbonate Urethane Resin Dispersion 1>
1,500 g of a polycarbonate diol (a reaction product of 1,6-hexanediol and dimethyl carbonate (number average molecular weight (Mn): 1,200)) was placed in a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer. 220 g of 2,2-dimethylolpropionic acid (DMPA) and 1,347 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream and heated to 60 ° C. to dissolve DMPA. Next, 1,445 g (5.5 mol) of 4,4′-dicyclohexylmethane diisocyanate and 1.8 g of dibutyltin dilaurylate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 3 hours, An isocyanate-terminated urethane prepolymer was obtained. The reaction mixture was cooled to 80 ° C., 149 g of triethylamine was added thereto, and 4,340 g of the mixture was taken out, and, under vigorous stirring, was poured into a mixed solution of 5,400 g of water and 15 g of triethylamine. added. Next, 1,500 g of ice was added, 626 g of a 35 mass% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out a chain extension reaction, and the solvent was distilled off so that the solid content concentration became 30 mass%. Then, a polycarbonate urethane resin dispersion liquid 1 having a structure derived from an alicyclic diisocyanate was obtained.

Table 2 shows the average particle size of the resin particles of Preparation Examples 1 to 6 of resin dispersions containing resin particles.

(Preparation example 1 of silver particle dispersion)
<Preparation of silver particle dispersion liquid 1>
66.8 g of silver nitrate, a dispersant polymer having a carboxyl group (trade name: Disperbic 190, manufactured by Big Chemie Japan Co., Ltd., solvent: water, 40% by mass of nonvolatile components, acid value: 10 mgKOH / g, amine value: 0 mgKOH / g ) 7.2 g and cholic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 2.2 g were added to ion-exchanged water 100 g and vigorously stirred to obtain a suspension. 100 g of dimethylaminoethanol (manufactured by Wako Pure Chemical Industries, Ltd.) was gradually added to the obtained suspension so that the water temperature did not exceed 50 ° C., and then heated in a water bath having a water temperature of 50 ° C. for 3 hours. Stir to obtain a reaction solution. The obtained reaction liquid was filtered through a glass filter (trade name: GC-90, manufactured by ADVANTEC, average pore size: 0.8 μm) to obtain a silver particle dispersion liquid 1 containing 20% by mass of silver particles.
A few μl of the obtained silver particle dispersion was sampled, a frozen body was prepared by a high-pressure freezing method, and the frozen body was cleaved to prepare a carbon replica film having a cross section. The replica film was placed on a TEM grid and observed with a transmission electron microscope (TEM) (manufactured by JEOL Ltd.) to find the major axis of silver particles in a TEM image in the range of 5 μm × 5 μm, and find the average. It was When the particle diameter of the silver particles was confirmed by TEM, it was spherical and the average particle diameter was 25 nm.

(Preparation Examples 2 to 5 of silver particle dispersion)
<Preparation of silver particle dispersions 2 to 5>
In the preparation of the silver particle dispersion liquid 1, except that the average particle size of the silver particles was changed as shown in Table 3 below by adjusting the addition rate of dimethylaminoethanol and the water temperature, the silver particle dispersion liquid 1 was prepared. Similarly to the preparation, silver particle dispersions 2 to 5 containing 15% by mass of silver particles were obtained.

(Preparation Example 6 of silver particle dispersion)
<Preparation of silver particle dispersion liquid 6>
In the preparation of the silver particle dispersion 1, the silver particle dispersion 6 was prepared in the same manner as in the preparation of the silver particle dispersion 1 except that cholic acid was changed to propionic acid (manufactured by Wako Pure Chemical Industries, Ltd.). Got Further, with respect to the obtained silver particle dispersion liquid 6, the average particle diameter of silver particles was determined in the same manner as the silver particle dispersion liquid 1.

Table 3 shows the average particle size of silver particles in each dispersion.

(Preparation Example 7 of silver particle dispersion)
<Preparation of silver particle dispersion 7>
A first solution was obtained by dissolving 50 g of silver nitrate in 1 L of distilled water. On the other hand, 22.2 g of oxalic acid was dissolved in 1 L of distilled water to obtain a second solution. The first solution and the second solution were mixed to obtain a mixed solution containing silver oxalate. Impurities were removed from this mixed solution. 3 g of polyethylene glycol (dispersing agent) was added to 1 L of the mixed solution, and the mixture was stirred for 50 minutes while applying ultrasonic waves. Thereby, silver oxalate was dispersed. This mixed solution was put into an autoclave. This mixed solution was pressurized at a pressure of 0.5 MPa. The mixed solution was heated to 140 ° C. while being stirred at a speed of 1300 rpm. Stirring was carried out at this temperature for 30 minutes to obtain a liquid containing fine particles containing silver as a main component. The average value of the arithmetic average roughness Ra of these fine particles was 2.0 nm.
The liquid containing fine particles containing silver as a main component was subjected to a centrifugal separator to remove excess polyethylene glycol. Further, this precipitate was put into ethylene glycol monoethyl ether acetate (ECA) and stirred. The precipitate was taken out and the excess ethylene glycol monoethyl ether acetate was removed with a centrifuge. The precipitate was heat-dried for a predetermined time to obtain a silver particle dispersion 7 which was a composition containing fine silver particles. This composition contains 90% by weight of silver particles and 10% by weight of other substances (mainly ethylene glycol monoethyl ether acetate).
Regarding the obtained silver particle dispersion, the particle diameter of the silver particles was confirmed by a transmission electron microscope (manufactured by JEOL Ltd.) in the same manner as in the silver particle dispersion 1, and the average particle diameter was 98 nm. The fine particles are flaky.

(Preparation Example 8 of silver particle dispersion)
<Preparation of silver particle dispersion 8>
A silver particle dispersion 8 was obtained in the same manner as in the preparation of the silver particle dispersion 7, except that the stirring condition of the mixed solution charged into the autoclave was 1000 rpm.
With respect to the obtained silver particle dispersion, the particle diameter of the silver particles was confirmed with a transmission electron microscope (manufactured by JEOL Ltd.) in the same manner as in the silver particle dispersion 1, and the average particle diameter was 105 nm. The fine particles are flaky.

(Example of preparation of silver-based ink)
<Preparation of silver-based ink 1>
20.0 mass% of silver particle dispersion liquid 1, dimethylaminoethanol (manufactured by Wako Pure Chemical Industries, Ltd.) 0.01 mass%, 1,2-propanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) 36.0 mass%, 3-Ethyl-3-hydroxymethyloxetane (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 7.0% by mass, LS-106 (Kao Co., polyoxyalkylene alkyl ether) 1.0% by mass as a surfactant, antiseptic and fungicide 0.1% by mass of Proxel LV (manufactured by Avicia) as an agent, 1.7% by mass of resin dispersion liquid 1 of polyester urethane resin particles (solid content: 0.5% by mass), and the total amount becomes 100% by mass. A residual amount of ion-exchanged water was added to and mixed with and stirred, and then filtered through a polypropylene filter (trade name: syringe filter, manufactured by Sartorius Co., Ltd.) having an average pore diameter of 0.2 μm to obtain a silver base ink 1.

<Preparation of silver-based ink 2>
Silver particle dispersion 2 14.0% by mass, dimethylaminoethanol (manufactured by Wako Pure Chemical Industries, Ltd.) 0.01% by mass, 1,2-propanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) 25.0% by mass, 7.0% by mass of 3-ethyl-3-hydroxymethyloxetane (manufactured by Tokyo Kasei Kogyo Co., Ltd.), 1.0% by mass of BYK-33 (manufactured by BYK Chemie) as a surfactant, and Proxel LV (Avicia) as an antiseptic and fungicide. 0.1% by mass, 1.7% by mass of the resin dispersion liquid 21 of polyester urethane resin particles (solid content: 0.5% by mass), and ion-exchanged water is left so that the total amount becomes 100% by mass. The amounts were added, mixed, stirred, and then filtered through a polypropylene filter having an average pore size of 0.2 μm (trade name: syringe filter, manufactured by Sartorius) to obtain a silver base ink 2.

<Preparation of silver-based inks 3 to 8>
In the preparation of the silver base ink 2, the silver base ink 3 was prepared in the same manner as the silver base ink 2 except that the silver particle dispersion liquid 2 was changed to the silver particle dispersion liquids 3 to 6 and the silver particle dispersion liquids 7 to 8. ~ 8 was obtained.

  For the obtained silver-based inks 1 to 8, the particle size of silver particles was confirmed by a transmission electron microscope (manufactured by JEOL Ltd.) in the same manner as in the silver particle dispersion liquid 1, and it was confirmed that the silver particle dispersion liquids used. It was confirmed that they were the same.

(Examples 1-27, Comparative Examples 1-7)
<Preparation of ink>
Inks were prepared by adding the compounds shown in Table 4 as dyes to the above-mentioned silver-based inks 1 to 8 by weight percent. Further, when the resin-containing ink was prepared, the ink was prepared by fixing the concentration of the added resin solid content to 0.5% by mass. The dye names C-1, C-2, C-8, C-12, C-15, C-16, and C-21 shown in Table 4 are compounds in specific examples of the compound represented by the general formula (1). An example number is shown.

Next, on the ink jet printer (IPSiO GXe5500 manufactured by Ricoh Co., Ltd.) filled with each of the obtained inks, the silver ink forms a solid image on the recording medium EJK-EGNA450 (manufactured by Elecom Co., Ltd.) under an environment of 25 ° C. did.
As shown in Table 4, the solid images were evaluated for glossiness, chromaticity (b ^* value), chromaticity unevenness, and scratch resistance according to the following evaluation criteria. The results are shown in Table 4.

[Evaluation of glossiness]
The 20 ° glossiness of the solid image was measured by a glossiness meter (manufactured by BYK Gardener, Microtrigloss) and evaluated according to the following criteria. The desired level is S or higher.
SS: 20 ° gloss is 500 or more S: 20 ° gloss is 400 or more and less than 500 A: 20 ° gloss is 300 or more and less than 400 B: 20 ° gloss is 100 or more and less than 300 C: 20 ° gloss Less than 100

[Evaluation of chromaticity b ^* value]
The “chromaticity (color value (b ^* value)” of CIE L ^* a ^* b ^* color coordinates was measured using an X-Rite 938 spectrophotometric densitometer (manufactured by X-Rite), and the following criteria were used. evaluated. The desired level is rank B or higher.
Rank A: b ^* value is -3 or less Rank B: b ^* value is greater than -3 and is 0 or less Rank C: b ^* value is greater than 0

[Evaluation of chromaticity unevenness]
This is an evaluation of variation in the b ^* value, and the horizontal direction of a solid image of 15 cm × 4 cm is equally divided into 10 and measured 10 times, evaluated by the difference between the Max value and the Min value, and the desired level is rank A. Becomes
Rank A: b ^* value Max value of 10 point measurement-Min value is 0.5 or less Rank B: b ^* value 10 point measurement Max value-Min value is more than 0.5 and 1 or less Rank C: b ^* value Max value-Min value of 10-point measurement exceeds 1

[Evaluation of scratch resistance]
The dried recording material was set on a Gakushin-type abrasion fastness tester AB-301 (trade name, manufactured by Tester Sangyo Co., Ltd.), and a friction piece (load; load; white cotton cloth (JIS L 0803 compliant)) was attached to the contact portion. It was rubbed 10 times with 300 g), the deterioration degree was visually observed, and evaluated according to the following criteria. The desired level is A or higher.
S: The number of scratches is less than 5, and the base is invisible.
A: The number of scratches is 5 or more and less than 10 and the base is invisible.
B: The number of scratches is 10 or more, and the base is exposed.

400 image forming apparatus 401 exterior of image forming apparatus 401c cover of apparatus body 404 cartridge holder 410 main tanks 410s, 410c, 410m, 410y for each color of silver (S), cyan (C), magenta (M), yellow (Y) Main tank 411 Ink storage container 413 Ink discharge port 414 Storage container case 420 Mechanism part 434 Discharge head 436 Supply tube

Patent No. 4165860 Patent No. 4078283

Claims (5)

An ink containing silver particles having an average particle diameter of 100 nm or less and a compound represented by the following general formula (1).

In the general formula (1), n represents 1 or 2, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₅ represents hydrogen, halogen, or 1 carbon atom. represents ~ 3 alkyl group, Y ₁ and Y ₂ represents an alkyl group having 1 to 6 carbon atoms, Z is represents a counter ion. Note that X ₁ and X ₂ represent hydrogen, halogen, an alkyl group, or an alkoxy group. Further, the aromatic ring may be condensed with another aromatic ring, and when the aromatic ring is condensed with another aromatic ring, the condensed aromatic ring does not have a substituent.   The ink according to claim 1, wherein the compound represented by the general formula (1) is contained in an amount of 0.01% by mass or more and 0.5% by mass or less based on the total amount of the ink.   The ink according to claim 1 or 2, which contains resin particles having an average particle diameter of 10 nm or more and 30 nm or less. A printed matter having a printed layer containing silver particles having an average particle diameter of 100 nm or less and a compound represented by the following general formula (1).

In the general formula (1), n represents 1 or 2, R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group having 1 to 3 carbon atoms, and R ₅ represents hydrogen, halogen, or 1 carbon atom. represents ~ 3 alkyl group, Y ₁ and Y ₂ represents an alkyl group having 1 to 6 carbon atoms, Z is represents a counter ion. Note that X ₁ and X ₂ represent hydrogen, halogen, an alkyl group, or an alkoxy group. Further, the aromatic ring may be condensed with another aromatic ring, and when the aromatic ring is condensed with another aromatic ring, the condensed aromatic ring does not have a substituent.   The printed matter according to claim 4, wherein the printed layer contains resin particles having an average particle diameter of 10 nm or more and 30 nm or less.

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