JP2012143871A - Printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed matter that has superior metallic glossiness and is formed with an image superior in fixability to a printing medium.SOLUTION: This printed matter printed with an ink containing silver particles on the printing medium is characterized in that surface Ag density by XPS measurement is not lower than 29 mass% and not higher than 93 mass%. When the surface Ag density by the XPS measurement is set as X[mass%] and surface C density by the XPS measurement is set as X[mass%], it is preferable that a relationship of 0.03≤X/(X+X)≤0.60 is satisfied. More preferably, an average particle diameter of the silver particles is ≥3 nm and ≤100 nm.

Description

  The present invention relates to a printed matter.

  As inks used for ink jet printing, generally, so-called full-color images are formed using cyan, magenta, yellow, and black inks. In order to improve the image quality of the formed image, the ink is multicolored (for example, six colors including light magenta and light cyan inks in addition to the above four types of ink).

  On the other hand, in the commercial printing field for magazine covers, New Year's cards, greeting cards, etc., so-called foil stamping, in which metal foil, represented by aluminum foil, is transferred onto a medium with a mold, is used in combination with normal color printing. Therefore, improvements in the design and high added value of printed materials have been attempted. However, when trying to reproduce a printed material close to the above-mentioned foil stamping by the inkjet method, although a pseudo metallic luster using the glossiness of the media can be obtained, a strong metallic luster such as bulk metal (metal foil) is not There was a problem that could not be expressed.

Therefore, in recent years, ink jet ink (metal ink) using metal particles has been proposed (see, for example, Patent Document 1).
However, the ink proposed in Patent Document 1 cannot realize the metallic luster inherent to the metal material, that is, the metallic luster equivalent to the foil press printing.
In addition, for the purpose of enhancing the metallic luster, the reduction of the amount of the binder resin was studied, but there was a problem that the adhesion of the printing part to the printing medium by the metallic material was lowered.

JP 2007-297423 A

  An object of the present invention is to provide a printed matter on which an image having excellent metallic gloss and excellent fixability to a printing medium is formed.

Such an object is achieved by the present invention described below.
The printed matter of the present invention is a printed matter obtained by printing an ink containing silver particles on a print medium,
The surface Ag concentration by XPS measurement in the printing part formed using the ink is 29% by mass or more and 93% by mass or less.
Thereby, it is possible to provide a printed matter on which an image having excellent metallic gloss and excellent fixability to a printing medium is formed.

In the printed matter of the present invention, it is preferable that the surface C concentration by XPS measurement in the printed portion formed using the ink is 2% by mass or more and 43% by mass or less.
Thereby, the metallic glossiness of an image can be made especially excellent.
In the printed matter of the present invention, when the surface Ag concentration by XPS measurement is X _Ag [mass%] and the surface C concentration by XPS measurement is X _C [mass%] in the printed part formed using the ink, 0 0.03 ≦ X _C / (X _Ag + X _C ) ≦ 0.60 is preferably satisfied.
Thereby, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent.

In the printed matter of the present invention, the average particle size of the silver particles is preferably 3 nm or more and 100 nm or less.
Thereby, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent.
In the printed matter of the present invention, the ink is preferably applied onto the print medium by an inkjet method.
Thereby, even if a printed matter has a fine print pattern, a desired pattern can be obtained reliably.

In the printed matter of the present invention, it is preferable that the ink is produced using an ink containing α, β-alkanediol (α, β is any integer not exceeding the carbon number).
Thereby, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent.
In the printed matter of the present invention, it is preferable that the ink is produced using the ink containing trimethylolpropane.
Thereby, the metallic glossiness of the image can be further improved, and the fixability (rubbing resistance) of the image to the printing medium can be further improved. In addition, since the ink ejection stability can be further improved, it can be more suitably applied to the production of printed matter by the inkjet method.

In the printed material of the present invention, the silver particles are preferably coated with polyvinylpyrrolidone.
Thereby, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent. Furthermore, silver particles having excellent dispersion stability can be obtained.

It is a perspective view which shows schematic structure of an inkjet apparatus.

Hereinafter, preferred embodiments of the present invention will be described in detail.
《Printed matter》
As inks used for ink jet printing, generally, so-called full-color images are formed using cyan, magenta, yellow, and black inks. In order to improve the image quality of the formed image, the ink is multicolored (for example, six colors including light magenta and light cyan inks in addition to the above four types of ink).

However, there is a problem that the metallic luster cannot be expressed even with the use of multicolor ink as described above. In recent years, ink jet ink (metal ink) using metal particles has been proposed. However, conventionally, the metallic luster inherent to the metal material cannot be fully exhibited.
Further, when another manufacturing method is used for the purpose of enhancing the metallic luster by using another manufacturing method, there is a problem that the adhesion of the printing part to the printing medium by the metal material is lowered.

  Accordingly, the present inventor has focused on the surface state of the metal in the printed material for the purpose of solving the above problems, and as a result of intensive research, has reached the present invention. That is, the printed matter of the present invention is obtained by printing an ink containing silver particles on a print medium, and a surface Ag concentration by XPS measurement in a printed portion formed using the ink is 29% by mass or more and 93% by mass. % Or less.

In the present invention, the reason why silver is used as the metal material is that among various metal materials, silver itself has an excellent metallic luster.
Further, in the present invention, the surface Ag concentration by XPS measurement in the printing part formed using the ink containing silver particles is 29% by mass or more and 93% by mass or less, but the surface Ag concentration by XPS measurement is less than the lower limit value. If this is the case, the glossiness of the printed matter is significantly reduced. On the other hand, when the surface Ag concentration by XPS measurement exceeds the upper limit, the fixability (rubbing resistance) of the image to the print medium is significantly lowered.

XPS measurement (measurement by X-ray photoelectron spectroscopy) is, for example, an X-ray photoelectron spectrometer ESCA-5700 (manufactured by ULVAC-PHI), PHI-5800ci (manufactured by ULVAC-PHI), ESCA-1000 (manufactured by Shimadzu Corporation), etc. Can be used.
Surface Ag concentration by XPS measurement is the amount of ink applied to the printing medium per unit area, the composition of the ink (Ag particle size, preparation method, content, type of additive, content, dispersion medium composition, etc. ), And can be adjusted according to the type of printing medium.

  As described above, in the present invention, the surface Ag concentration by XPS measurement in the printing part formed using the ink containing silver particles may be 29% by mass or more and 93% by mass or less, but 36% by mass or more 93%. It is preferably no greater than mass%, more preferably no less than 48 mass% and no greater than 93 mass%, and even more preferably no less than 68 mass% and no greater than 80 mass%. Thereby, the effects as described above are more remarkably exhibited.

  The surface C concentration by XPS measurement in a printing part formed using ink is preferably 2% by mass or more and 43% by mass or less, more preferably 2% by mass or more and 32% by mass or less, and 11% by mass. More preferably, it is 20 mass% or less. Thereby, the metallic glossiness of the formed image can be made particularly excellent. On the other hand, if the value is less than the lower limit, the abrasion resistance of the image formed by the bright pigment may not be maintained.

In the printed matter of the present invention, the surface Ag concentration by XPS measurement is X _Ag [mass%] and the surface C concentration by XPS measurement is X _C [mass%] in a printing part formed using an ink containing silver particles. It is preferable that the relationship 0.03 ≦ X _C / (X _Ag + X _C ) ≦ 0.60 is satisfied, and the relationship 0.03 ≦ X _C / (X _Ag + X _C ) ≦ 0.40 is satisfied. It is more preferable that the relationship 0.12 ≦ X _C / (X _Ag + X _C ) ≦ 0.25 is further satisfied. By satisfying such a relationship, the metallic glossiness of the image can be made particularly excellent, and the fixing property (rubbing resistance) of the image to the printing medium can be made particularly excellent. .
The ink and print medium that can be suitably used for the production of the printed matter of the present invention will be described in detail below.

(ink)
As described above, the ink used for producing the printed material of the present invention contains silver particles. As described above, when the ink contains silver particles, an image having an excellent metallic gloss can be formed. Silver is the metal with the highest visible light reflectivity and high whiteness among various metals, so it can be used in various metal colors such as gold and copper by overlapping with other color inks. (Color metallic) can be expressed. In order to favorably express the color metallic, the state on the silver print medium that emits a metallic luster is important. In other words, when other color inks are stacked, a higher metallic luster is required for the area of silver alone. In that case, when the silver concentration of the surface layer is 45 mass% or more and 93 mass% or less by XPS measurement, Preferably it is 68 mass% or more and 92 mass% or less, Even when the area | region of another color is formed on a printing medium, a preferable color metallic color Can be expressed.
The ink may be applied to the printing medium by any method, but is preferably applied by an ink jet method. Thereby, even if a printed matter has a fine print pattern, a desired pattern can be obtained reliably.

In the following description, the case where ink is applied to a print medium by an inkjet method will be mainly described.
The average particle size of the silver particles is preferably 3 nm or more and 100 nm or less, and more preferably 20 nm or more and 65 nm or less. When the particle size is 3 nm or less, the transmission / absorption of visible light becomes remarkable. When the particle size is 100 nm or more, the precipitation of silver particles in the ink becomes remarkable. By setting the average particle diameter of the silver particles in the above range, a silver layer that efficiently reflects visible light can be formed using ink, so that the glossiness (high-quality feeling) of the image and the fixability to the printing medium (resistance to resistance) (Rubbing property) can be made particularly excellent. Further, ink ejection stability (landing position accuracy, ejection amount stability, etc.) by the ink jet method can be made particularly excellent, and an image with a desired image quality can be more reliably formed over a long period of time. . In the present specification, the “average particle size” means a volume-based average particle size unless otherwise specified.

  Moreover, it is preferable that the particle size d90 in the particle size accumulation curve of silver particles is 50 nm or more and 150 or less. As a result, a high surface flatness of the silver layer formed using the ink can be obtained. As a result, the glossiness (high-quality feeling) of the image and the fixing property (rubbing resistance) to the printing medium are particularly excellent. be able to. Further, ink ejection stability (landing position accuracy, ejection amount stability, etc.) by the ink jet method can be made particularly excellent, and an image with a desired image quality can be more reliably formed over a long period of time. .

  Moreover, it is preferable that the particle size d10 in the particle size accumulation curve of silver particles is 2 nm or more and 20 nm or less. Thereby, the ratio of the small particle diameter silver particle which does not contribute to metal reflection can be reduced. Furthermore, the glossiness (high-quality feeling) of the image formed using the ink and the fixing property (rubbing resistance) to the printing medium can be made particularly excellent. Further, ink ejection stability (landing position accuracy, ejection amount stability, etc.) by the ink jet method can be made particularly excellent, and an image with a desired image quality can be more reliably formed over a long period of time. .

  The content of silver particles in the ink is preferably 3.0% by mass or more and 18% by mass or less, and more preferably 3.5% by mass or more and 15% by mass or less. As a result, the metallic glossiness of the image formed using the ink can be made particularly excellent, and the fixing property (rubbing resistance) of the image to the printing medium can be made particularly excellent. . Further, the ejection stability of the ink by the ink jet method and the storage stability of the ink can be made particularly excellent. Also, to achieve good image quality and abrasion resistance in a wide density range from low to high density of silver particles (content per unit area) on the print medium when printed. Can do. For this reason, for example, even if the printed matter obtained using the ink has regions with different silver particle densities, the image quality of the printed matter can be improved.

The silver particles may be prepared by any method. For example, the silver particles can be suitably formed by preparing a solution containing silver ions and an organic substance that functions as a dispersant and reducing the silver ions. it can.
In particular, the silver particles are preferably prepared by adding a silver nitrate solution containing ethylene glycol and silver nitrate to a PVP solution containing polyvinyl pyrrolidone and ethylene glycol, followed by heating reaction. Thereby, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent. Further, since the ink ejection stability can be made particularly excellent, it can be suitably applied to the production of printed matter by the ink jet method.
When silver particles are prepared as described above, the heating temperature is preferably 60 ° C. or higher and 200 ° C. or lower, and more preferably 70 ° C. or higher and 170 ° C. or lower. Thereby, the effects as described above are more remarkably exhibited.

  The ink used for producing the printed material of the present invention may be a so-called aqueous ink containing 50% by mass or more of water or a non-aqueous ink containing water in a range of less than 50% by mass. Compared with non-aqueous (solvent-based) inks, water-based inks are less reactive to piezo elements used in recording heads, organic binders contained in print media, etc., and will dissolve and corrode. As a result, it is advantageous to ensure that the glossiness of the printed matter is excellent. Further, in the case of non-aqueous (solvent) ink, there is also a problem that if the solvent used has a high boiling point and low viscosity, it takes a long time to dry. Furthermore, compared with solvent-based inks, water-based inks have a very low odor, and more than half of the water-based inks have the advantage of being good for the environment. Examples of water include ion exchange water, reverse osmosis water, distilled water, and ultrapure water.

In the ink, water mainly functions as a dispersion medium for dispersing silver particles. When the ink contains water, the dispersion stability of the silver particles can be improved, and unintentional drying of the ink in the vicinity of the nozzle of the droplet discharge device as described later (dispersion medium) Since drying on the printing medium to which ink is applied can be performed quickly while preventing evaporation), high-speed printing of a desired image can be suitably performed over a long period of time.
The content of water in the ink is not particularly limited, but is preferably 20% by mass or more and 95% by mass or less, and more preferably 50% by mass or more and 90% by mass or less.

The ink used for producing the printed material of the present invention preferably contains an organic dispersant that disperses silver particles. Thereby, the discharge stability by the ink jet system of ink and the storage stability of ink can be made particularly excellent.
The silver particles used for producing the printed material of the present invention are preferably those coated with polyvinylpyrrolidone as a dispersant. Thereby, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent.

  The ink used for producing the printed material of the present invention is preferably one containing α, β-alkanediol (α, β is any integer not exceeding carbon number). As a result, good wettability of ink and permeability of the solvent can be secured for a wide range of media, so that the metallic glossiness of the image can be made particularly excellent and the fixability of the image to the printing medium ( (Abrasion resistance) can be made particularly excellent.

  When the ink contains α, β-alkanediol, the content of α, β-alkanediol in the ink is preferably 0.5% by mass or more and 10% by mass or less, and 1.0% by mass or more and 5% or less. More preferably, it is 0.0 mass% or less. Thereby, the metallic glossiness of the image can be further improved, and the fixability (rubbing resistance) of the image to the printing medium can be further improved.

  As α, β-alkanediol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-octane Examples include diol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and the like. Preferable examples include 1,2-hexanediol and 1,6-hexanediol.

  The ink used for producing the printed material of the present invention preferably contains a humectant that is solid at room temperature. Thereby, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent. Further, since the ink ejection stability can be made particularly excellent, it can be suitably applied to the production of printed matter by the ink jet method.

  The ink used for producing the printed material of the present invention preferably contains trimethylolpropane as a humectant that is solid at room temperature. Thereby, the metallic glossiness of the image can be further improved, and the fixability (rubbing resistance) of the image to the printing medium can be further improved. In addition, since the ink ejection stability can be further improved, it can be more suitably applied to the production of printed matter by the inkjet method.

  When the ink contains a humectant that is solid at room temperature, the content of the humectant in the ink is preferably 20% by mass or less, and more preferably 5% by mass or less and 18% by mass or less. Thereby, the metallic glossiness of the image can be further improved, and the fixability (rubbing resistance) of the image to the printing medium can be further improved. In addition, since the ink ejection stability can be further improved, it can be more suitably applied to the production of printed matter by the inkjet method. On the other hand, if the value falls below the lower limit of the above range, the viscosity becomes too low, the discharge head meniscus becomes unstable and continuous printing becomes difficult, and a large amount of mist is generated, which adversely affects the nozzle plate. It becomes easy to generate problems such as. In addition, when the upper limit of the above range is exceeded, the viscosity increases and the moisturizing agent does not penetrate into the receiving layer together with the solvent, and the moisturizing agent remains on the surface of the printed matter, resulting in deterioration of the metallic luster. It tends to occur.

The ink used for producing the printed material of the present invention preferably contains triethanolamine. As a result, the ink can be weakly alkaline and the dispersion of the silver colloid becomes more stable. As a result, the storage stability of the ink is improved, the generation of aggregates can be reduced, the unevenness of the surface of the printed matter can be prevented, and the metallic gloss can be prevented from being lowered due to light scattering.
In addition, the metallic glossiness of the image can be made particularly excellent, and the fixability (rubbing resistance) of the image to the printing medium can be made particularly excellent.

  When the ink contains triethanolamine, the content of triethanolamine in the ink is preferably 0.1% by mass or more and 2.0% by mass or less, and 0.3% by mass or less and 1.5% by mass. The following is more preferable. Thereby, the metallic glossiness of the image can be further improved, and the fixability (rubbing resistance) of the image to the printing medium can be further improved.

The ink used for producing the printed material of the present invention may contain components other than those described above (other components).
Examples of such components include alcohols such as hexylene glycol, ethanol, ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol, and acetylene glycol surfactants (Olfin (R) E1010 manufactured by Nissin Chemical Industry Co., Ltd.). Surfactol (R) 104PG manufactured by Air Products and Chemicals Inc.), surfactants such as polysiloxane surfactants (fluorine-based other types of nonionic surfactants and anionic surfactants, amphoteric interfaces, etc.) Other surfactants such as activators may be added), pH adjusters such as aqueous potassium hydroxide, penetrants, organic binders, drying inhibitors such as urea compounds, surface tensions such as acetylene glycol compounds Conditioner, thiourea, silicon And waxes such as silver wax, antiseptics, head rust preventives, thickeners and the like.

When the ink contains a solid content other than the above (hereinafter also referred to as “other solid content”), the content of the other solid content in the ink is preferably 5% by mass or less, and preferably 1% by mass or less. Is more preferable.
The solid content in the ink is preferably 50% by mass or less, more preferably 3.6% by mass or more and 40% by mass or less, and further preferably 12% by mass or more and 27% by mass or less. preferable. Thereby, the discharge stability of the ink can be made particularly excellent.

  The viscosity of the ink (viscosity at 25 ° C. measured according to JIS Z8809 using a vibration viscometer) is not particularly limited, but is 2.0 mPa · s or more and 12.0 mPa · s or less. It is more preferable that it is 3.0 mPa · s or more and 8.0 mPa · s or less. As a result, the droplet ejection stability can be improved, and the ink that has landed on the printing medium can be more reliably prevented from spreading unintentionally. Can be formed.

(Print media)
As a printing medium to which ink is applied, in addition to paper such as plain paper, special paper having an ink receiving layer, etc., for example, the region including the surface to which ink is applied includes various plastics, ceramics, glass, metal, The base material etc. which were comprised with these composite materials are mentioned.
<Method for producing printed matter>
Next, a preferred embodiment of the method for producing a printed matter of the present invention as described above will be described.
FIG. 1 is a perspective view showing a schematic configuration of an ink jet apparatus (droplet discharge apparatus).
The printed matter manufacturing method of the present embodiment includes a step (droplet discharge step) of discharging ink as described above toward a print medium using an ink jet device (droplet discharge device) as shown in FIG. .

(Discharge process)
Hereinafter, droplet discharge using the ink jet printer 1 as a droplet discharge device will be described.
As shown in FIG. 1, an ink jet printer 1 as a droplet discharge device has a frame 2. A platen 3 is provided on the frame 2, and a print medium P is fed onto the platen 3 by driving a paper feed motor 4. The frame 2 is provided with a rod-shaped guide member 5 in parallel with the longitudinal direction of the platen 3.

A carriage 6 is supported on the guide member 5 so as to be capable of reciprocating in the axial direction of the guide member 5. The carriage 6 is connected to a carriage motor 8 via a timing belt 7 provided in the frame 2. The carriage 6 is reciprocated along the guide member 5 by driving the carriage motor 8.
The carriage 6 is provided with a droplet discharge head 9 and an ink cartridge 10 for supplying ink as liquid to the droplet discharge head 9 is detachably disposed. The ink in the ink cartridge 10 is supplied from the ink cartridge 10 to the print head 9 by driving a piezoelectric element (not shown) provided in the droplet discharge head 9 and formed on the nozzle formation surface of the droplet discharge head 9. A plurality of nozzles are ejected to the print medium (base material) P fed onto the platen 3.
This makes it possible to produce printed matter.

(Heating process)
In the method for producing printed matter, in addition to the above-described ejection step, a heating step for overheating the print medium to which ink has been applied may be provided.
By providing a heating step, when the printing medium S has high water retention, or when the ink contains a liquid component having low volatility at a relatively high content (for example, a liquid component having a boiling point of 160 ° C. or higher). Even when the content is 3% by mass or more), it is possible to effectively prevent the liquid components constituting the ink from remaining in the finally obtained printed matter, thereby improving the durability and reliability of the printed matter. In addition, it can be made particularly excellent and can reliably prevent a decrease in glossiness of the image due to the remaining volatile components.
As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to what was mentioned above.

For example, in the above-described embodiment, the case where a colloidal liquid is used as the ink has been representatively described. However, the ink may not be a colloidal liquid.
For example, in the above-described embodiment, the piezo method is used as the droplet discharge method. However, the present invention is not limited to this, and in the present invention, for example, the ink is discharged by bubbles generated by heating the ink. Various known techniques such as methods can be applied.
In the above-described embodiment, the ink is described as being used for ejection by the ink jet method, but the ink may be applied to other printing methods.

Next, specific examples of the present invention will be described.
[1] Preparation of ink (Preparation Example 1)
Polyvinyl pyrrolidone (weight average molecular weight 10,000) was heated at 70 ° C. for 15 hours and then cooled at room temperature. The polyvinyl pyrrolidone (PVP) 1000g was added to the ethylene glycol solution 500ml, and the PVP solution was adjusted. In another container, 500 ml of ethylene glycol was added, 128 g of silver nitrate was added, and the mixture was sufficiently stirred with a magnetic stirrer to prepare a silver nitrate solution. While stirring the PVP solution using an overhead mixer at 120 ° C., the silver nitrate solution was added and the reaction was allowed to proceed by heating for about 80 minutes. And it was made to cool at room temperature after that. The obtained solution was centrifuged for 10 minutes with a centrifuge at 2200 rpm. Thereafter, the separated silver particles were taken out and added to 500 ml of an ethanol solution in order to remove excess PVP. Then, further centrifugation was performed to take out silver particles. Furthermore, the taken-out silver particle was dried on 35 degreeC and 1.3 Pa conditions with the vacuum dryer.

In this example, the average particle diameter of silver particles was measured using “Microtrac UPA” (manufactured by Nikkiso Co., Ltd.), and the measurement conditions were a refractive index of 0.2-3.9i, a solvent (water ) Was 1.333, and the measured particle shape was spherical.
Silver particles obtained as described above, 1,2-hexanediol, trimethylolpropane as a humectant solid at room temperature, Surfynol 465 (manufactured by Nissin Chemical Industry Co., Ltd.), triethanolamine, Polyflow 401 (manufactured by Nissin Chemical Industry Co., Ltd.) and ion-exchanged water were mixed to obtain an ink.

(Preparation Examples 2 to 6)
An ink was prepared in the same manner as in Preparation Example 1 except that the composition shown in Table 1 was obtained by adjusting the type and amount of components used in the preparation of the ink.
(Preparation Example 7)
In Preparation Example 7, silver particles used for ink preparation were manufactured by the following method. 17 mL of trisodium citrate dihydrate and 0.36 g of tannic acid were dissolved in 50 mL of water made alkaline by adding 3 mL of 10N-NaOH aqueous solution. To the obtained solution, 3 mL of 3.87 mol / L silver nitrate aqueous solution was added and stirred for 2 hours to obtain a silver colloid solution. The obtained silver colloid solution was desalted by dialysis until the electrical conductivity was 30 μS / cm or less. After dialysis, the coarse metal colloid particles were removed by centrifugation at 3000 rpm for 10 minutes.

Thereafter, the silver particles obtained as described above, 1,2-hexanediol, trimethylolpropane as a humectant solid at room temperature, Surfynol 465 (manufactured by Nissin Chemical Industry Co., Ltd.), and triethanol An ink was prepared by mixing amine, polyflow 401 (manufactured by Nissin Chemical Industry Co., Ltd.), and ion-exchanged water.
In the inks prepared in Preparation Examples 1-6, the silver particles were coated with polyvinylpyrrolidone on the surface.

Table 1 shows the configuration of the inks of each of the preparation examples. In Table 1, Olefin E1010 (manufactured by Nissin Chemical Industry Co., Ltd.) is OE1010, Surfynol 104PG (manufactured by Nissin Chemical Industry Co., Ltd.) is S104PG, Surfynol 465 (manufactured by Nissin Chemical Industry Co., Ltd.) is S465, Polyflow 401 ( Kyoeisha Chemical Co., Ltd.) PF401, polyether modified siloxane BYK-348 (Bic Chemie) BYK348, propylene glycol PG, 2-pyrrolidone 2-PD, EPG-1200 (Mitsui Chemicals) EPG1200, 1,2-hexanediol is represented by 1,2-HD, trimethylolpropane is represented by TMP, and triethanolamine is represented by TEA.
The viscosity of each of the inks of Preparation Examples 1 to 7 (viscosity at 25 ° C. measured using a vibration viscometer in accordance with JIS Z8809) is 3.5 mPa · s or more and 4.5 mPa · s or less. The value was within the range.

[2] Production of printed matter (Examples 1 to 16, Comparative Examples 1 to 5)
The ink described in Table 2 was printed at the printing density described in Table 2 using PX-G930 (manufactured by Seiko Epson Corporation) on the surface side where the ink receiving layer of the printing medium described in Table 2 was provided. .

As printing media, exclusive paper for inkjet (photographic paper): photographic paper <gloss> (KA4100PSKR, manufactured by Seiko Epson) (referred to as PGPP in Table 2), KOKUYO Label Sheet KJ-G2210 (manufactured by KOKUYO) PET media (PET-50A, manufactured by Lintec), transparent film IT-324F-C (manufactured by Plus Stationery), and EPSON Clear Proof film (WXCPF24R, manufactured by Seiko Epson) were used. In this specification, “duty” (print density) is a value calculated by the following equation.
duty (%) = number of actual printing dots / (vertical resolution × horizontal resolution) × 100
(In the formula, “number of actual printing dots” is the number of actual printing dots per unit area, and “vertical resolution” and “horizontal resolution” are resolutions per unit area, respectively.)

[3] Evaluation [3.1] Glossiness About the printed surface of the printed matter according to each of the above examples and comparative examples, a glossiness meter (MINOLTA MULTI GLOSS 268) was used to measure the glossiness at a turning angle of 60 °, Evaluation was made according to the following criteria.
A: Glossiness is 600 or more.
B: Glossiness is 450 or more and less than 600.
C: Glossiness is 300 or more and less than 450.
D: Glossiness is less than 300.

[3.2] Abrasion resistance With respect to the printed materials according to each of the above examples and comparative examples, at the time when 48 hours had elapsed since the production of the printed materials, a rust resistance test was performed according to JIS K5701, using a Southerland Lab Tester. Using the same method as described in [3.1] above, the gloss (turning angle 60 °) is also measured for the printed matter after the abrasion resistance test, and the reduction rate of the gloss before and after the abrasion resistance test is measured. And evaluated according to the following criteria.
A: The reduction rate of glossiness is less than 10%.
B: The reduction rate of glossiness is 10% or more and less than 20%.
C: The reduction rate of glossiness is 20% or more and less than 30%.
D: The reduction rate of glossiness is 30% or more.

These results are shown together with the types of ink used in the production of the printed materials of each Example and each Comparative Example, the surface Ag concentration X _Ag by XPS measurement, the surface C concentration X _C by XPS measurement, and the value of X _Ag + X _C Table 2 summarizes the results. The XPS measurement was performed using ESCA-100 (manufactured by Shimadzu Corporation), the X-ray source was set to Mg, the take-out angle was set to 90 °, the analysis diameter (spot size) was set to Φ1 mm, and the conditions (Passing energy 80 eV) were set in the Wide spectrum. , Dwell 25 msec, sweep 5, step 1 eV), and after confirming the entire constituent elements in the Narrow spectrum, the orbit of a predetermined element (Cl of energy of 32 eV, dwell 100 msec, sweep 5, step 0.1 eV) 2p, 1s of C, 1s of O, 3d of Ag, 2p of Al), and each element was quantitatively calculated from each spectrum area separated from the baseline using the Shirley method.

As is clear from Table 2, the printed matter according to the present invention was excellent in glossiness and abrasion resistance, whereas the comparative example did not give satisfactory results.
In addition, the ink according to the present invention is excellent in droplet ejection stability and storage stability, can stably eject droplets over a long period of time, and is preferably used for the production of printed matter. I was able to.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printer (printer) 2 ... Frame 3 ... Platen 4 ... Paper feed motor 5 ... Guide member 6 ... Carriage 7 ... Timing belt 8 ... Carriage motor 9 ... Droplet discharge head (print head) 10 ... Ink cartridge P ... Print media (base material)

Claims (8)

A printed matter obtained by printing ink containing silver particles on a print medium,
A printed matter having a surface Ag concentration of 29% by mass or more and 93% by mass or less by XPS measurement in a printing part formed using the ink.   2. The printed matter according to claim 1, wherein a surface C concentration by XPS measurement in a printing portion formed using the ink is 2% by mass or more and 43% by mass or less. When the surface Ag concentration by XPS measurement is X _Ag [mass%] and the surface C concentration by XPS measurement is X _C [mass%] in a printing part formed using the ink, 0.03 ≦ X _C / The printed matter according to claim 1 or 2, which satisfies a relationship of (X _Ag + X _C ) ≤0.60.   The printed matter according to any one of claims 1 to 3, wherein an average particle diameter of the silver particles is 3 nm or more and 100 nm or less.   The printed matter according to any one of claims 1 to 4, wherein the ink is applied onto the print medium by an inkjet method.   The printed matter according to any one of claims 1 to 5, wherein the printed matter is produced using an ink containing α, β-alkanediol (α, β is any integer not exceeding carbon number).   The printed matter according to any one of claims 1 to 6, wherein the printed matter is produced using an ink containing trimethylolpropane as the ink.   The printed matter according to any one of claims 1 to 7, wherein the silver particles are coated with polyvinylpyrrolidone.

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