WO2019065371A1 - Encre, article ayant une image formée, et procédé de formation d'image - Google Patents

Encre, article ayant une image formée, et procédé de formation d'image Download PDF

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Publication number
WO2019065371A1
WO2019065371A1 PCT/JP2018/034494 JP2018034494W WO2019065371A1 WO 2019065371 A1 WO2019065371 A1 WO 2019065371A1 JP 2018034494 W JP2018034494 W JP 2018034494W WO 2019065371 A1 WO2019065371 A1 WO 2019065371A1
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Prior art keywords
peak
particle size
less
image
volume
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PCT/JP2018/034494
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English (en)
Japanese (ja)
Inventor
禄人 田口
中林　亮
大柴　武雄
哲哉 加川
雅子 菊池
恒雄 柏木
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コニカミノルタ株式会社
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Priority to JP2019544986A priority Critical patent/JPWO2019065371A1/ja
Publication of WO2019065371A1 publication Critical patent/WO2019065371A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/02—Printing inks
    • C09D11/03—Printing inks characterised by features other than the chemical nature of the binder
    • C09D11/037—Printing inks characterised by features other than the chemical nature of the binder characterised by the pigment
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/30—Inkjet printing inks
    • C09D11/32—Inkjet printing inks characterised by colouring agents
    • C09D11/322—Pigment inks

Definitions

  • the present invention relates to an ink, an image formed article and an image forming method.
  • an ink containing a metallic pigment-based bright pigment such as an aluminum pigment or a pearl pigment (hereinafter referred to as “ink Sometimes abbreviated as ”)” may be used.
  • a metallic pigment-based bright pigment such as an aluminum pigment or a pearl pigment
  • Patent Document 1 discloses silver nanoparticles having an average particle diameter of 1 to 100 nm as an ink jet ink (hereinafter sometimes abbreviated as “ink jet ink”) used for forming such an image, and Disclosed are ink compositions comprising certain organic compounds and polymeric dispersants that coat silver nanoparticles, and a solvent.
  • Patent Document 2 discloses an ink composition in which the metallic gloss of an image-formed product is enhanced by using silver particles having a particle diameter d90 of 50 nm or more and 1 ⁇ m or less in a particle diameter accumulation curve.
  • Patent Document 3 discloses a coating material such as a printing ink for forming a conductive layer, which includes metal nanoparticles having a bimodal particle size distribution, in which there is a difference of at least 10 nm between intermediate particle diameters of two sections. Is disclosed.
  • the coating material enhances the mechanical stability, the frictional resistance, the surface properties, the gloss and the like of the coating formed by the use of metal nanoparticles having a bimodal particle size distribution.
  • a coating material comprising metal nanoparticles having a bimodal particle size distribution is also disclosed in US Pat.
  • the coating material of US Pat. No. 5,075,099 is directed to the interstices between larger particles by the use of silver nanoparticles having a bimodal particle size distribution (ie, silver nanoparticles comprising particles of large particle size and particles of small particle size).
  • silver nanoparticles having a bimodal particle size distribution ie, silver nanoparticles comprising particles of large particle size and particles of small particle size.
  • JP, 2009-227736, A JP 2011-241240 A JP 2012-511627 gazette Japanese Patent Publication No. 2010-507727
  • an image formed using the ink described in Patent Document 1 may contain bluish or reddish color different from the original color tone of silver, and it is difficult to obtain the color tone originally possessed by silver.
  • the ink described in Patent Document 2 can improve the gloss, the formed image may also contain bluish and reddish, and it is difficult to obtain the color tone that silver originally has The
  • Patent Document 3 and Patent Document 4 are for forming a conductive structure, and are not for image formation.
  • the present invention has been made in view of such circumstances, and provides an ink containing metal nanoparticles capable of forming an image having the inherent color tone of the metal in which the expression of a specific color tone is suppressed. To aim.
  • [1] containing metal nanoparticles and water, The ink, wherein the metal nanoparticles have an average particle diameter D1 of 25 nm to 70 nm, and have a peak half width of 30 nm to 120 nm in volume particle size distribution.
  • [2] The ink according to [1], wherein the half width of the peak is 40 nm or more and 100 nm or less.
  • [3] The ink according to [1] or [2], wherein the ratio of metal nanoparticles having a particle diameter of 40 nm or less to the total volume of the metal nanoparticles is 10% by volume or more and 50% by volume or less.
  • Silver nanoparticles and water wherein the silver nanoparticles have a first peak whose peak particle size is in the range of 5 nm to less than 45 nm, and a peak particle size of 45 nm to 100 nm in the volume particle size distribution Ink which has at least 2 peaks of the 2nd peak in a range, and the half value width of the 1st peak and the 2nd peak is 5 nm or more independently, respectively.
  • the ink according to [6], wherein the half-widths of the first peak and the second peak are each independently 10 nm or more.
  • the ink according to [6] or [7], wherein the half-widths of the first peak and the second peak are each independently 50 nm or less.
  • the two adjacent peaks in the volume particle size distribution of the silver nanoparticles have a small diameter side peak particle diameter / large diameter side peak particle diameter ratio of 0.3 or more and 0.8 or less, [6] to [8] ]
  • the ink in any one of. [10] The ink according to any one of [1] to [9], further comprising a dispersant adsorbed on the surface of the metal nanoparticles. [11] The ink according to any one of [1] to [10], further comprising emulsion resin particles. [12] The ink according to any one of [1] to [11], which is for image formation by an inkjet method.
  • the volume particle size distribution of the silver nanoparticles includes at least two peaks of a first peak having a peak particle size in the range of 5 to 45 nm and a second peak having a peak particle size in the range of 45 to 100 nm.
  • the image-formed product according to [19], wherein the half-widths of the first peak and the second peak are each independently 10 nm or more.
  • the image-formed product according to [19] or [20], wherein the half-widths of the first peak and the second peak are each independently 50 nm or less.
  • the two adjacent peaks in the volume particle size distribution of the silver nanoparticles have a small diameter side peak particle diameter / large diameter side peak particle diameter ratio of 0.3 or more and 0.8 or less, [19] to [21 ]
  • the image-formed product according to [13] to [24], wherein the sheet resistance of the metallic gloss layer is larger than 1 ⁇ 10 5.0 ⁇ / sq.
  • the present invention can provide an ink containing metal nanoparticles capable of forming an image having the inherent color tone of the metal in which the development of a specific color tone is suppressed.
  • the image formed by the metal nanoparticles may exhibit a color tone different from the original color tone of the metal.
  • this is because the development of the gloss by the metal nanoparticles is related to the reflection and scattering of light by the metal nanoparticles, and the absorption and reflection of light by the plasmon resonance of the metal nanoparticles. It is considered that the wavelength involved in the reflection, scattering and absorption of these lights changes with the particle diameter. For example, in the case of silver nanoparticles, when the amount of silver nanoparticles having a large particle diameter of 60 nm or more is small, the reflectance of red light (about 650 nm) is low.
  • silver particles having a particle diameter of several tens of nm show absorption near a wavelength of 400 nm. Therefore, in the reflection spectrum of the image formed using silver nanoparticles, dips in reflectance may be observed around 650 nm and around 450 nm.
  • metal nanoparticles generally contain a large amount of particles of a specific particle size, and their particle size distribution is sharp in peak (that is, narrow in half width).
  • the reflection spectrum of the image is not a flat shape such as the reflection spectrum of silver foil, but is an uneven shape, specifically different in reflectance depending on the wavelength. In some cases, only the reflectance of a specific wavelength may be high or low. Such deviation of the reflection spectrum is considered to be due to the wavelength at which silver nanoparticles having a particle diameter near the peak reflect and scatter.
  • the average particle size D1 is 25 nm or more and 70 nm or less It has been found that an image showing a flatter reflection spectrum can be obtained by forming an image using an ink containing metal nanoparticles having a peak half width of 30 nm or more and 120 nm or less in volume particle size distribution. Metal nanoparticles having such a particle size distribution include particles of various different particle sizes, and a relatively broad peak exists in the particle size distribution.
  • the wavelength at which particles of a certain particle size are difficult to reflect can be obtained by reflecting particles of other particle sizes to obtain the reflection spectrum inherent to the metal. be able to. Therefore, it becomes possible to form an image having the original color tone of the metal in which the expression of a specific color tone is suppressed.
  • a layer containing silver nanoparticles having a multimodal volume particle size distribution, wherein at least 90% of the silver nanoparticles are not fused to each other is used as a metallic gloss layer.
  • a metallic gloss layer By forming on a material, it has been found that an image showing a flatter reflection spectrum can be formed on various substrates. If the particle size distribution of silver nanoparticles contained in the metallic gloss layer is multimodal, the wavelength at which particles of a certain particle size are difficult to reflect is the particle size distribution of silver nanoparticles so that particles of other particle sizes are reflected. By adjusting, it is possible to make the reflection spectrum of the metallic gloss layer flatter. In addition, the presence of the large particle size particles and the small particle size particles makes it possible to enhance the reflectance by increasing the filling rate of the silver nanoparticles.
  • the ink of the present invention comprises metal nanoparticles and water.
  • Metal nanoparticles are nano-sized metal particles.
  • the main components of the metal nanoparticles include silver, gold, copper, aluminum, platinum, nickel, chromium, tin, zinc, indium, titanium, bismuth and the like. These metals may be alloys, mixtures or oxides comprising the aforementioned metals.
  • the main component means, for example, that the proportion of the metal or the alloy, the mixture or the acid value thereof with respect to the total of atoms contained in the metal nanoparticles is 50 atomic% or more.
  • a metal nanoparticle is a silver nanoparticle which has silver as a main component.
  • alloys containing silver include silver magnesium, silver copper, silver palladium, silver palladium copper, silver indium, silver bismuth and the like. Furthermore, the silver nanoparticles may contain a trace amount of other components which are inevitably contained, or may contain an oxide of silver.
  • the metal nanoparticles may be further surface-treated with citric acid or the like to enhance dispersion stability.
  • the metal nanoparticles have an average particle diameter D1 of 25 nm to 70 nm, and have a peak half width of 30 nm to 120 nm in volume particle size distribution. is there.
  • the half width in the present invention is the width (half width full width) of the particle diameter which is a half of the peak maximum value in the volume particle size distribution.
  • the average particle size D1 of the metal nanoparticles is in the range of 25 nm to 70 nm, the particle size is not extremely biased to the small particle size side or the large particle size side, so control of the particle size distribution of the metal nanoparticles Makes it easy to flatten the reflection spectrum.
  • the average particle diameter D1 is not particularly limited as long as it is within the above range, but preferably 30 nm or more and 65 nm or less from the viewpoint of not biasing the particle size distribution toward the small particle size side or the large particle size side. And 35 nm or more and 65 nm or less.
  • the half value width of the peak in the volume particle size distribution of the metal nanoparticles is 30 nm or more, preferably 35 nm or more, more preferably 40 nm or more. Furthermore, the half width is 120 nm or less, preferably 100 nm or less, more preferably 80 nm or less. If the half-width is 30 nm or more, the metal nanoparticles contain not only particles of average particle diameter and particles of particle diameter in the vicinity but also particles of various different particle diameters, so the particle diameter is in the vicinity of average particle diameter The wavelength at which one particle is difficult to absorb or reflect can be reflected by the other particle. In addition, if the half width is 80 nm or less, the amount of metal nanoparticles with a small particle diameter that easily absorbs a wavelength with a specific particle diameter can be suppressed.
  • the “peak” in the volume particle size distribution is a peak at which the volume frequency of the maximum value is 5% or more in the volume particle size distribution measured at intervals of 5 nm. That is, peaks having a volume frequency of maximum less than 5% are not included in the number of peaks in the present invention.
  • the particle size distribution of the metal nanoparticles at least one peak having the above-described half width may be present, and a plurality of peaks may be present.
  • the particle size distribution of the metal nanoparticles may be unimodal with one peak or multimodal with two or more peaks.
  • the proportion of metal nanoparticles having a particle diameter of 40 nm or less is preferably 10% by volume or more and 50% by volume or less, based on the total volume of the metal nanoparticles, and is 20% by volume or more and 45% by volume It is more preferable that Further, the ratio of metal nanoparticles having a particle diameter of 60 nm or more is preferably 10% by volume or more and 60% by volume or less, and is 20% by volume or more and 55% by volume or less based on the total volume of the metal nanoparticles. Is more preferred.
  • the average particle size of the metal nanoparticles and the half width of the peak are respectively within the above-mentioned specific ranges, and the plasmon absorption of the metal nanoparticles is on the short wavelength side, so the reflectance for short wavelengths is high.
  • the proportion of metal nanoparticles having a particle diameter of 40 nm or less is 10% by volume or more, for example, it is possible to suppress a drop in reflectance near 450 nm when silver nanoparticles are used.
  • the proportion of metal nanoparticles having a particle diameter of 60 nm or more with high reflectance to long wavelengths is 10% by volume or more, for example, depression of reflectance around 650 nm when silver nanoparticles are used is suppressed be able to.
  • the proportion of each of the metal nanoparticles having a particle diameter of 40 nm or less and / or the metal nanoparticles having a particle diameter of 60 nm or more to 60 volume% or less the particle diameter is biased to the small particle diameter side or the large particle diameter side Can be prevented, and the bias of reflected (or absorbed) wavelengths can also be prevented. In this way, it is possible to make the reflection spectrum closer to flatter.
  • the average particle size D1 of the metal nanoparticles, the half width of the peak in the volume particle size, the ratio of metal nanoparticles having a particle size of 40 nm or less, and the ratio of metal nanoparticles having a particle size of 60 nm or more are, for example, metal nanoparticle dispersion liquid described later It can be adjusted by the input amount of the raw material at the time of preparation of and the dropping time of the reducing agent.
  • the half-width and the ratio of particles with a specific particle diameter can also be adjusted by mixing two or more kinds of metal nanoparticles (for example, commercially available products) whose average particle diameter and particle size distribution are known. be able to.
  • the metal nanoparticles are silver nanoparticles.
  • Silver nanoparticles are those that have multimodality in their volume particle size distribution. Although at least two peaks may be present in the volume particle size distribution, two or more and four or less peaks are preferable, two or three peaks are more preferable, and two peaks are particularly preferable. If the silver nanoparticles contained in the ink are multimodal, the reflection spectrum of the metallic luster layer does not depend on the reflection or absorption of light by silver nanoparticles of a specific particle size, but particles of a certain particle size are absorbed. The wavelength which is hard to be reflected or reflected can be reflected by particles of other particle sizes. Also, if the number of peaks present in the volume particle size distribution of silver nanoparticles is 4 or less, the particle size of silver nanoparticles is appropriately limited, so control of the reflection spectrum by adjustment of particle size distribution (ie, Flattening is facilitated.
  • the "at least two peaks" in the volume particle size distribution are respectively present on the small particle size side and the large particle size side bordering on the particle size (i.e. valley) having the minimum value of the volume frequency.
  • the peak is the peak where the maximum value of the volume frequency is the peak particle size, and the volume frequency of the maximum value is a peak of 5% or more. That is, peaks having a volume frequency of maximum less than 5% are not included in the number of peaks in the present invention.
  • the particle diameter which takes the minimum value of the volume frequency is the particle diameter which takes 70% or less of the volume frequency of the smaller one of the adjacent maximum values. Therefore, even if the particle size is lower in volume frequency than the adjacent particle size, if the volume frequency exceeds 70% of the smaller one of the adjacent local maximum values, the particle size takes the local value. Do not consider it as a part of nearby peaks.
  • peaks present in the volume particle size distribution of the silver nanoparticles include a first peak having a peak particle size in the range of 5 nm to less than 45 nm, and a second peak having a peak particle size in the range of 45 nm to 100 nm Is preferably included.
  • the peak particle diameter of the first peak is more preferably 10 nm or more and less than 45 nm, and particularly preferably 15 nm or more and less than 45 nm.
  • the peak particle diameter of the second peak is more preferably 45 nm or more and 90 nm or less, and particularly preferably 50 nm or more and 80 nm or less.
  • each of the first peak and the second peak is preferably in the above range.
  • the half value width of each of the first peak and the second peak is preferably independently 5 nm or more, and more preferably 10 nm or more. Further, the half width is preferably 60 nm or less, more preferably 55 nm or less, and particularly preferably 50 nm or less. If the half-width is 5 nm or more, the silver nanoparticles contain not only particles of peak particle diameter but also particles of various different particle diameters, so the wavelength at which particles of peak particle diameter are difficult to absorb or reflect is Can be reflected by the In addition, if the half width is 60 nm or less, the range of the particle size distribution of the silver nanoparticles is not too wide, and control of the reflection spectrum by adjustment of the particle size distribution is easy.
  • the peak particle sizes of such other peaks are not particularly limited.
  • the peak particle sizes of the other peaks may be in the range of 5 nm to less than 45 nm as in the first peak, or in the range of 45 nm to 100 nm as in the second peak, or in other ranges, for example , Less than 5 nm, or more than 100 nm.
  • the half value width of the other peaks is not particularly limited, but is preferably in the same range as the first peak and the second peak.
  • peak particle diameter ratio small diameter side peak particle diameter / large diameter side peak particle diameter ratio
  • peak particle diameter ratio is the ratio of the peak particle size of the first peak to the peak particle size of the second peak (the peak particle size of the first peak / second peak Peak particle size ratio).
  • the peak particle size ratios are d1 / d2 and d2 / d3 when the peak particle sizes are d1, d2 and d3 from the small particle size side to the large particle size side. It becomes two. When the number of peaks further increases, the peak particle size ratio also increases, but it is preferable that all peak particle size ratios independently become values within the above range. If the peak particle size ratio is 0.3 or more and 0.8 or less, since there is an appropriate distance between the two peaks, control of the reflection spectrum using silver nanoparticles of each peak particle size is facilitated . In particular, if the peak particle size ratio is 0.8 or less, the two peaks are too close to function like silver nanoparticles constituting one peak.
  • the number of peaks of silver nanoparticles, peak particle size and half width are adjusted, for example, by mixing unimodal silver nanoparticles having a specific peak particle size, average particle size and half width at an appropriate ratio. be able to.
  • the peak particle size, average particle size, and half width of the unimodal silver nanoparticles are adjusted, for example, by the addition amount of the raw material at the time of preparation of the silver nanoparticle dispersion described later, the dropping time of the reducing agent, etc. Can.
  • metal nanoparticles Physical properties of metal nanoparticles Particle size distribution of metal nanoparticles, particle size such as average particle size D1, number of peaks, peak particle size and half width, ratio of metal nanoparticles with particle size of 40 nm or less, and particle size of 60 nm or more
  • the proportion of metal nanoparticles in the film can be measured by SEM observation. Specifically, it can be measured by the following procedure.
  • D50 (median diameter) in the particle size distribution be the average particle diameter D1 (volume average particle diameter) of the metal nanoparticles. Further, from the particle size distribution, the number of peaks, peak particle diameter, peak half width, ratio of metal nanoparticles having a particle diameter of 40 nm or less, and ratio of metal nanoparticles having a particle diameter of 60 nm or more are measured. Further, the small diameter side peak particle diameter / large diameter side peak particle diameter ratio is determined for the two adjacent peaks.
  • the particle diameter of the metal nanoparticle in this invention means the average particle diameter of the metal nanoparticle itself which does not contain the dispersing agent (adsorbed on the surface of the metal nanoparticle).
  • the ink may further comprise a dispersant adsorbed on the surface of the metal nanoparticles. Thereby, the metal nanoparticles are easily dispersed in the solvent.
  • the ink also contains emulsion resin particles, the interaction between the dispersant and the emulsion resin particles can facilitate uniform mixing of the metal nanoparticles and the emulsion resin particles via the dispersant.
  • the dispersant is preferably a polymer dispersant from the viewpoint of excellent affinity with the emulsion resin.
  • the polymer dispersant is a resin having an adsorptive group for adsorbing on the surface of metal nanoparticles.
  • the adsorptive group include a carboxyl group and a thiol group. That is, in the present invention, whether or not the dispersant is adsorbed on the surface of the metal nanoparticles depends on whether the dispersant has an adsorption group and the metal nanoparticles are dispersed without being precipitated in the ink. It can be judged.
  • resin which comprises a polymer dispersing agent is a homopolymer or copolymer of a hydrophilic monomer.
  • the copolymer of the hydrophilic monomer may be a copolymer of a hydrophilic monomer and a hydrophobic monomer.
  • hydrophilic monomers include carboxyl or acid anhydride group-containing monomers ((meth) acrylic acids such as acrylic acid and methacrylic acid, unsaturated polyvalent carboxylic acids such as maleic acid, and maleic anhydride), and alkylenes.
  • Oxide modified (meth) acrylic acid ester monomers such as ethylene oxide modified (meth) acrylic acid alkyl ester are included.
  • hydrophobic monomers examples include (meth) acrylate monomers (methyl (meth) acrylate, ethyl (meth) acrylate etc.), styrenic monomers (styrene, ⁇ -methylstyrene, vinyl toluene etc.), ⁇ And olefinic monomers (such as ethylene, propylene and 1-butene) and carboxylic acid vinyl ester monomers (such as vinyl acetate and vinyl butyrate).
  • acrylate monomers methyl (meth) acrylate, ethyl (meth) acrylate etc.
  • styrenic monomers styrene, ⁇ -methylstyrene, vinyl toluene etc.
  • ⁇ And olefinic monomers such as ethylene, propylene and 1-butene
  • carboxylic acid vinyl ester monomers such as vinyl acetate and vinyl butyrate
  • the polymer dispersant when it is a copolymer, it may be any of a random copolymer, an alternating copolymer, a block copolymer, or a comb-type copolymer (or a comb-type graft copolymer). Among them, the polymer dispersant is preferably a comb block copolymer, from the viewpoint that the affinity to the emulsion resin particles described later is good.
  • the comb block copolymer refers to a copolymer including a linear polymer forming a main chain and another type of polymer grafted onto a constituent unit derived from a monomer constituting the main chain.
  • the main chain contains a structural unit derived from (meth) acrylic acid ester
  • the side chain is a polyoxyalkyl group (a long chain polyoxyalkyl such as EO-PO copolymer group) Group block copolymers are included.
  • the comb block copolymer can suppress aggregation of metal nanoparticles to a higher degree because the grafted side chains cause steric hindrance. As a result, the dispersibility of the metal nanoparticles is enhanced, and thus it is easier to suppress the ejection failure due to the aggregated metal nanoparticles.
  • the acid value of the dispersant is preferably 1 mg KOH / g to 80 mg KOH / g.
  • the acid value is 1 mg KOH / g or more, the dispersant tends to be hydrophilic, and thus the dispersibility in the ink (particularly, water-based ink) can be easily enhanced.
  • the acid value is 80 mgKOH / g or less, it is easy to suppress the remarkable decrease in the durability of the metallic gloss layer due to the swelling of the dispersant in the metallic gloss layer.
  • the acid value of the dispersant is more preferably 1 mgKOH / g or more and 60 mgKOH / g or less, still more preferably 2 mg KOH / g or more and 50 mg KOH / g or less, and still more preferably 3 mg KOH / g or more and 45 mg KOH / g or less Preferably, it is 5 mg KOH / g or more and 40 mg KOH / g or less.
  • the acid value can be measured according to JIS K 0070.
  • the acid value of the dispersant is determined by Fourier transform infrared spectroscopy (FT-IR) to identify the type of dispersant (for example, product name of polymer dispersant used for image formation).
  • the acid value of the same dispersant may be measured according to JIS K 0070.
  • the type of dispersant may be specified by 1 H NMR or gas chromatography-mass spectrometry (GC / MS).
  • the molecular weight of the dispersant is preferably 1,000 or more and 100,000 or less, and more preferably 2,000 or more and 50,000 or less.
  • Examples of commercially available dispersants include Solsparse 24000, Solsparse 24000GR, Solsparse 32000, Solsparse 44000, and Solsparse 46000 manufactured by Lubrizol, Azisper PB 822 manufactured by Ajinomoto Fine Techno Co., Ltd.
  • DISPERBYK-102 DISPERBYK-187, DISPERBYK-194N, DISPERBYK-190, DISPERBYK-191, DISPERBYK-199, DISPERBYK-2000, DISPERBYK-2001, DISPERBYK-2015, DISPERBYK-2015, DISPERBYK-2050, DISPERBYK-2150, and DISPERBYK-2069
  • EFKA is a registered trademark of BASF AG
  • FLORENE TG-750W manufactured by Kyoeisha Chemical Co., Ltd., and the like.
  • the dispersant adsorbed on the surface of the metal nanoparticles can be obtained, for example, by reducing metal ions (which become metal nanoparticles) in an aqueous solvent containing the dispersant.
  • Emulsion Resin Particles The ink may further include emulsion resin particles.
  • the emulsion resin particles can function as a binder resin, and can interact with the surface of the metal nanoparticles and the dispersant adsorbed thereon to enhance the adhesion of the metal nanoparticles to the substrate.
  • emulsion resin particles examples include (meth) acrylic resin, urethane resin, polyolefin resin, polyester resin, polyvinyl chloride resin (eg polyvinyl chloride polymer, vinyl chloride-vinylidene chloride copolymer), epoxy Resin, polysiloxane resin, fluorine resin, styrene copolymer (eg, styrene-butadiene copolymer, styrene- (meth) acrylate copolymer, etc.), vinyl acetate copolymer (eg, ethylene-vinyl acetate copolymer) Etc. etc. are included.
  • (meth) acrylic resin, urethane resin, polyolefin resin, polyvinyl chloride resin, epoxy resin, polysiloxane resin, fluorocarbon resin, styrene copolymer, vinyl acetate Copolymers are preferred, and urethane resins and (meth) acrylic resins are more preferred.
  • the urethane resin is produced, for example, by reacting a sulfonate-containing polyol (a1) with an organic polyisocyanate (a2) in an atmosphere of excess of isocyanate groups, adding a low molecular weight polyol (a3-1) and an aqueous solvent, and further reacting Thus, an emulsion of isocyanate group-terminated prepolymer may be obtained, and the low molecular weight polyamine (a3-2) may be added and further reacted.
  • sulfonate-containing polyol (a1) examples include sulfonate-containing polyester polyols, sulfonate-containing polyether polyols, sulfonate-containing polycarbonate polyols and the like.
  • organic polyisocyanate (a2) examples include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate and 1,4-tetramethylene diisocyanate, o-xylene diisocyanate, Included are aromatic aliphatic diisocyanates such as m-xylene diisocyanate and p-xylene diisocyanate, and alicyclic polyisocyanates such as isophorone diisocyanate (hereinafter abbreviated as IPDI).
  • aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate
  • aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate and 1,4-tetramethylene diisocyanate
  • o-xylene diisocyanate Included are aromatic aliphatic diisocyanates such as m
  • the low molecular weight polyol (a3-1) and the low molecular weight polyamine (a3-2) can function as a chain extender.
  • Examples of low molecular weight polyols (a3-1) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol and the like; low molecular weight polyamines (a3-2) Examples include ethylene diamine, propylene diamine, diethylene triamine and the like.
  • the aqueous solvent may be a mixed solvent of an organic solvent such as N-methyl pyrrolidone (NMP) or propylene glycol dimethyl ether (DMPDG) and water.
  • NMP N-methyl pyrrolidone
  • DMPDG propylene glycol dimethyl ether
  • the (meth) acrylic resin may be one obtained by polymerizing the monomer (b1) with the water-soluble initiator (b2) in an aqueous solution containing the polymeric emulsifier (b3).
  • Examples of the monomer (b1) include (meth) acrylic acid alkyl esters such as methyl (meth) acrylate and ethyl (meth) acrylate, (meth) acrylic acid alkoxy alkyl esters such as methoxybutyl (meth) acrylate, styrene, ⁇ And aromatic vinyl compounds such as methylstyrene, hydrolyzable silane group-containing vinyl compounds such as vinyltriethoxysilane; (meth) acrylamide compounds such as N-methylol acrylamide and the like.
  • water soluble initiator (b2) examples include sodium persulfate, potassium persulfate, ammonium persulfate and the like.
  • the high molecular weight emulsifier (b3) may be a water soluble resin, and examples thereof include a carboxyl group-containing polymer.
  • the carboxyl group-containing polymer is a homopolymer or copolymer of a carboxy group-containing unsaturated monomer.
  • Examples of carboxy group-containing unsaturated monomers include (meth) acrylic acid, and examples of monomers copolymerizable therewith include the same as the monomer (b).
  • D2 / D1 which is a ratio of the average particle diameter D1 of the metal nanoparticles to the average particle diameter D2 of the emulsion resin particles, satisfy 0.05 ⁇ D2 / D1 ⁇ 1.
  • D2 / D1 is less than 1, the surface of the metal nanoparticles can be covered relatively densely (with relatively no gaps) in the ink even if the content weight of the emulsion resin particles is small, Also in the metallic luster layer, the voids around the metallic nanoparticles can be reduced. As a result, the increase in the refractive index of the metallic gloss layer and the decrease in the extinction coefficient can be reduced, and the scattered light can be reduced, whereby the reflectance (glossiness) can be enhanced.
  • the ratio D2 / D1 more preferably satisfies 0.1 ⁇ D2 / D1 ⁇ 1, and further preferably satisfies 0.2 ⁇ D2 / D1 ⁇ 0.95.
  • the average particle size D2 of the emulsion resin particles can be measured in the same manner as the method of measuring the average particle size D1 of the metal nanoparticles.
  • the average particle diameter D2 is determined by the addition amount of the chain lengthening agent (a3) or the reaction product of the sulfonate containing polyol (a1) and the organic polyisocyanate (a2)
  • the reaction time with the chain extender (a3), the composition of the aqueous solvent (content ratio of DMPDG, etc.) and the like can be adjusted.
  • the average particle diameter D2 is, for example, the composition (styrene content ratio etc.) of the monomer (b1), the compounding amount of the water-soluble initiator (b2), the polymeric emulsifier ( It can be adjusted by the composition of b3).
  • the emulsion resin particles Even if the content mass M2 (%) of the emulsion resin particles is reduced by setting D2 / D1 to a certain level or less, the emulsion resin particles form relatively densely the periphery of the metal nanoparticles in the ink. ) Can be covered. That is, since the content mass M2 (%) of the emulsion resin particles in the ink can be reduced, the content ratio of the metal nanoparticles in the obtained metallic gloss layer can be increased, whereby the reflectance can also be increased. .
  • the ratio M1 / M2 of the content mass M1 (%) of metal nanoparticles in the ink to the content mass M2 (%) of emulsion resin particles in the ink is 1.3 ⁇ M1 / M2 ⁇ 35 It is preferable to satisfy.
  • M1 / M2 is 1.3 or more, the content ratio of the resin that easily absorbs light in the obtained metallic gloss layer can be appropriately reduced, and the content ratio of the metal nanoparticles can be moderately increased. It is easy to increase the reflectance.
  • M1 / M2 is 35 or less, the content ratio of the resin in the metallic gloss layer to be obtained is appropriately high, and therefore, the adhesiveness with the substrate of the metallic gloss layer and the film strength can be easily enhanced.
  • the ratio M1 / M2 more preferably satisfies 1.5 ⁇ M1 / M2 ⁇ 35, and still more preferably 2 ⁇ M1 / M2 ⁇ 30.
  • a ratio V1 of the contained volume V1 (%) of metal nanoparticles in the ink to the contained volume V2 (%) of the emulsion resin particles in the ink It is preferable that / V2 satisfy 0.25 ⁇ V1 / V2 ⁇ 6.
  • V1 / V2 is 0.25 or more, the content ratio of the resin that easily absorbs light in the obtained metallic gloss layer can be appropriately reduced, and the content ratio of the metal nanoparticles can be moderately increased. It is easy to increase the reflectance.
  • V1 / V2 When V1 / V2 is 6 or less, the content ratio of the resin in the metallic gloss layer to be obtained is appropriately high, and therefore, the adhesiveness with the substrate of the metallic gloss layer and the film strength can be easily enhanced. More preferably, V1 / V2 satisfies 0.4 ⁇ V1 / V2 ⁇ 5, and still more preferably satisfies 0.6 ⁇ V1 / V2 ⁇ 4.
  • the total amount (M1 + M2) (%) of the content mass M1 (%) of metal nanoparticles in the ink and the content mass M2 (%) of emulsion resin particles in the ink preferably satisfies 1 ⁇ M1 + M2 ⁇ 35.
  • the total amount (M1 + M2) is 1 or more, since the solid content amount contained in the ink is appropriately large, it is easy to form a metallic gloss layer having a desired thickness, and a sufficient reflectance can be easily obtained. If the total amount (M1 + M2) is 35 or less, the amount of solid content contained in the ink is not too large, so the viscosity does not increase excessively and the dischargeability from the inkjet head is unlikely to be impaired.
  • the total (M1 + M2) more more preferably satisfies 2 ⁇ M1 + M2 ⁇ 35, and still more preferably 3 ⁇ M1 + M2 ⁇ 30.
  • the solvent ink contains at least water, but may further contain an organic solvent in any proportion.
  • organic solvents include polyhydric alcohols (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol Monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monopropyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Glycol ethers such as recalled monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether; ethylene glycol, glycerin, 2-
  • the solvent preferably contains an organic solvent having a boiling point of 150 ° C. or more from the viewpoint of preventing the ink from drying in the vicinity of the ink jet head and enhancing the dischargeability from the head.
  • organic solvents include glycerin, propylene glycol, triethylene glycol monomethyl ether and the like.
  • the organic solvent is contained in the ink, it is preferably 20% by mass to 50% by mass with respect to the total mass of the ink, and more preferably 30% by mass to 45% by mass.
  • the ink may further contain other components other than the above components as long as the effects of the present invention are not impaired.
  • examples of other components include known surfactants (surface conditioners).
  • surfactants include anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates and fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols and polyoxy acids It includes nonionic surfactants such as ethylene / polyoxypropylene block copolymers, cationic surfactants such as alkylamine salts and quaternary ammonium salts, and surfactants of silicone type and fluorine type.
  • anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates and fatty acid salts
  • polyoxyethylene alkyl ethers polyoxyethylene alkyl allyl ethers
  • acetylene glycols and polyoxy acids It includes nonionic surfactants such as ethylene / polyoxypropylene block copolymers, cationic surfact
  • silicone surfactants include KF-351A, KF-352A, KF-642 and X-22-4272 manufactured by Shin-Etsu Chemical Co., Ltd., BYK-307, BYK-345, BYK manufactured by Big Chemie Co. 347 and BYK-348 ("BYK” is a registered trademark of Big Chemie Co.), and TSF 4452 manufactured by Toshiba Silicone Co., Ltd.
  • the content of the surfactant can be, for example, 0.001% by mass or more and less than 1.0% by mass with respect to the total mass of the ink.
  • the viscosity of the ink is preferably 1 cP or more and less than 100 cP, and more preferably 1 cP or more, from the viewpoint of further enhancing the ejection stability from the nozzles. It is more preferably 50 cP or less, and still more preferably 1 cP or more and 15 cP or less.
  • the image-formed product of the present invention is formed by applying the above-described ink of the present invention to the surface of a substrate, metal nanoparticles contained in the ink of the present invention, and optionally dispersants and resins And a metallic luster layer on the surface of the substrate.
  • the particle size distribution of the silver nanoparticles in the metallic gloss layer can be measured by observing the cut surface of the image-formed product with an SEM as described above.
  • the metallic gloss layer is a layer containing metal nanoparticles.
  • the metallic gloss layer also contains a dispersant and a resin.
  • the metallic gloss layer is preferably substantially composed of metal nanoparticles adsorbed with the above-mentioned dispersant and a binder resin (that is, emulsion resin particles in the ink).
  • the total content of the metal nanoparticles and the binder resin adsorbed by the dispersant is preferably 90% by mass to 100% by mass, and more preferably 95% by mass to 100% by mass, based on the total mass of the metallic gloss layer. It is more preferable that
  • the thickness of the metallic gloss layer is not particularly limited, but is preferably 0.005 ⁇ m or more and 10 ⁇ m or less, and more preferably 0.01 ⁇ m or more and 1.0 ⁇ m or less, from the viewpoint of sufficiently exhibiting metallic gloss. More preferably, it is 0.1 ⁇ m or more and 0.5 ⁇ m or less.
  • the metallic gloss layer is substantially free of a compound that can significantly change the electrical resistance, such as a known conductive agent.
  • the sheet resistance of the metallic luster layer is preferably greater than 1 ⁇ 10 5.0 ⁇ / sq, more preferably greater than 5 ⁇ 10 5.0 ⁇ / sq, and particularly preferably 1 ⁇ 10 6.0 ⁇ / sq Greater than.
  • the proportion of silver nanoparticles fused together in the metallic gloss layer can be confirmed as follows. With respect to the image-formed product, an SEM photograph of 10 fields of the surface or cross section of the metallic gloss layer is taken, and the number of fused particles and the number of unfused particles in the obtained SEM photograph are Visually count and calculate the percentage of non-fused particles relative to the total number of particles. In addition, let the particle
  • Sheet resistance can be made into the value obtained by measuring by a contact type (4 probe method) using a well-known volume resistivity measuring device.
  • the metallic gloss layer of the image-forming material preferably has a standard deviation of less than 4%, more preferably less than 2%, of the reflectance per 20 nm value measured in the wavelength range of 460 nm to 780 nm.
  • the standard deviation of reflectance is less than 4%, the reflection spectrum is relatively flat, and a specific wavelength is not strongly reflected or absorbed, so that the expression of a specific tint is suppressed
  • the image has an original color tone of metal.
  • the standard deviation of the reflectance of the metallic gloss layer can be determined by measuring the reflectance every 20 nm over the wavelength range of 460 nm to 780 nm using a spectrophotometer and determining the standard deviation of the measured reflectance. .
  • the standard deviation of the reflectance of the metallic gloss layer indicates the solvent of the colorant layer. Etc. or based on the reflectivity of the metallic gloss layer measured after removal by ion beam etching or the like.
  • the image-forming material may contain layers other than the metallic gloss layer described above.
  • the image-formed product may have a primer layer on the substrate side of the metallic gloss layer to further improve the adhesion of metal nanoparticles, or on the surface side (the opposite side of the substrate), It may have a colorant layer or a protective layer.
  • the primer layer can be a layer formed of a material conventionally used to enhance adhesion to a substrate such as a pigment containing metal nanoparticles.
  • the primer layer contains a fixing resin.
  • the film thickness of the primer layer is not particularly limited, it is preferably 0.05 ⁇ m or more and 100 ⁇ m or less from the viewpoint of sufficiently enhancing the adhesion of the metallic gloss layer to the substrate, and is 0.1 ⁇ m or more and 50 ⁇ m or less Is more preferably 0.5 ⁇ m or more and 20 ⁇ m or less.
  • the resin for fixing may be any resin conventionally used to enhance the adhesion of the pigment containing metal nanoparticles and the like to the substrate, and may be the same resin as the binder resin described above .
  • the fixing resin examples include (meth) acrylic resin, epoxy resin, polysiloxane resin, maleic acid resin, polyolefin resin, vinyl resin, polyamide resin, polyvinyl pyrrolidone, polyhydroxystyrene, polyvinyl alcohol, nitrocellulose, acetic acid Cellulose, ethyl cellulose, ethylene-vinyl acetate copolymer, urethane resin, polyester resin, alkyd resin and the like are included. These fixing resins may be used alone or in combination of two or more.
  • the above-mentioned color material layer is a layer for changing the color tone of an image-formed product to develop a specific metallic color.
  • the color material layer can be a layer containing a known pigment or dye and a resin for fixing the pigment or dye.
  • the resin for fixing the pigment or dye can be selected from the same resin as the binder resin (that is, the resin component in the emulsion resin) contained in the ink and the resin for fixing contained in the primer layer.
  • the coloring material layer may contain these resins singly or in combination of two or more.
  • the above-mentioned protective layer is a layer that enhances the abrasion resistance and the like of the metallic gloss layer, and suppresses the detachment of the metal nanoparticles from the image-forming material.
  • the protective layer can be a layer containing a binder resin (that is, a resin component in the emulsion resin) contained in the ink and a resin similar to the fixing resin contained in the primer layer.
  • the said protective layer may contain these resin individually by 1 type, and may contain it in combination of 2 or more types.
  • the image-formed material can be preferably used in applications where the expression of metallic gloss is required.
  • the above-mentioned image-formed matter can be used for recorded matter.
  • the recorded matter may be a single character or a set of characters, or may be an image such as a figure, a picture, or a picture.
  • the image forming method of the present invention includes the steps of applying the above-described ink of the present invention to the surface of a substrate, and drying the applied ink.
  • the substrate for applying the ink is not particularly limited, and absorbent substrates including coated papers including uncoated papers and coated papers including art papers, coated papers, light-weight coated papers, fine coated papers, cast papers and the like Materials (paper base), polyester (PE), polyvinyl chloride (PVC), polyethylene (PE), polyurethane (PU), polypropylene (PP), acrylic resin (PA), polycarbonate (PC), polystyrene (PS), Non-absorbent substrates (plastic substrates) composed of plastics including acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PET) and polybutadiene terephthalate (PBT), and metals and glasses
  • Non-absorbent inorganic media can be used, including.
  • the method of applying the ink to the surface of the substrate is not particularly limited, and the above ink may be applied to the surface of the substrate using a roll coater, a spin coater, etc., spray coating, immersion method, screen
  • the ink may be applied to the surface of the substrate by a method such as printing, gravure printing, or offset printing, or the ink may be deposited on the surface of the substrate by an inkjet method.
  • the inkjet method is preferable from the viewpoint of forming a more precise recorded matter.
  • the ink of the present invention containing metal nanoparticles and water may be ejected from the nozzle of the inkjet head to land on the surface of the substrate.
  • the drying temperature at this time is preferably less than 100 ° C., and more preferably less than 80 ° C.
  • a metallic gloss layer is formed by this process.
  • the dried ink may be heated.
  • the emulsion resin particles are preferably thermally fused by heating.
  • the heating temperature of the ink may be any temperature at which the emulsion resin particles can be thermally fused, and is preferably at least the glass transition temperature of the emulsion resin particles. Specifically, the heating temperature is preferably, for example, 40 ° C. or more, and the upper limit temperature needs to be equal to or less than the heat resistance temperature of the base material and the emulsion resin particles. Further, by further adding a film forming aid to the ink, it is also possible to form a film at a Tg or less of the emulsion resin particles.
  • the drying step and the heating step may be performed separately or may be performed simultaneously.
  • the drying temperature and heating temperature be equal to or higher than the glass transition temperature of the emulsion resin particles.
  • the image forming method of the present invention may further include the step of forming a primer layer on the surface of the substrate before the metallic gloss layer is formed by the above-described steps, as needed.
  • the image forming method of the present invention may further include the step of forming a coloring material layer or a protective layer on the surface side of the obtained metallic gloss layer.
  • the primer layer can be formed by applying a resin composition containing a binder resin to the surface of the base before the metallic gloss layer is formed. After application of the resin composition, the resin composition may be dried by heating or the like to form a film of binder resin. The drying temperature at this time may be, for example, less than 100 ° C.
  • the color material layer can be formed by applying a resin composition containing a known pigment or dye and a binder resin for fixing them on the metallic gloss layer.
  • the protective layer can be formed by applying a resin composition containing a binder resin on the metallic gloss layer. After application of these resin compositions, the resin composition may be dried by heating or the like to form a film of binder resin. The drying temperature at this time may be, for example, less than 100 ° C.
  • the resin contained in each resin composition can be selected from the same resin as the binder resin contained in the primer layer.
  • the method for applying each resin composition is not particularly limited, but the inkjet method and the electrophotographic method are preferable from the viewpoint of facilitating formation of a fine image.
  • Material A-1-1. Preparation of silver nanoparticle dispersion ⁇ silver nanoparticle dispersion 1> In a 1 L separable flask having a flat stirring blade and a baffle, 8.4 g of DISPERBYK-190 (manufactured by Bick Chemie Co., Ltd.) and 269 g of ion exchanged water were charged, and stirring was performed to dissolve DISPERBYK-190. . Subsequently, 70 g of silver nitrate dissolved in 269 g of ion-exchanged water was charged into the separable flask while stirring.
  • the obtained reaction solution was placed in a stainless steel cup, and 2 L of ion exchanged water was further added, and then the pump was operated to perform ultrafiltration.
  • the solution in the stainless steel cup decreased, ion-exchanged water was again added, and purification was repeated until the conductivity of the filtrate became 100 ⁇ S / cm or less.
  • the filtrate was concentrated to obtain a silver nanoparticle dispersion 1 with a solid content of 30% by mass.
  • the ultrafiltration apparatus used was an ultrafiltration module AHP1010 (Asahi Kasei Co., Ltd., molecular weight cut off: 50000, number of membranes used: 400), and a tube pump (Masterflex Co., Ltd.) connected by a tygon tube. .
  • the average particle size and particle size distribution of silver nanoparticles in the obtained solution were measured by the method described in the evaluation method described later. As a result, the average particle diameter D1 was 43 nm, and the half width of the peak was 60 nm.
  • ⁇ Silver nanoparticle dispersion 2> 9.6 g of DISPERBYK-190 and 265 g of ion-exchanged water were charged into a 1 L separable flask having a flat stirring blade and a baffle and stirred to dissolve DISPERBYK-190. Subsequently, 80 g of silver nitrate dissolved in 265 g of ion-exchanged water was charged into the separable flask while stirring. Further, 80 g of ammonia water was added and stirring was carried out, and then the above separable flask was put into a water bath, and heated and stirred until the temperature of the solution stabilized at 80 ° C. Thereafter, 209 g of dimethylaminoethanol was added to the separable flask, and stirring was further continued for 3 hours while maintaining the temperature at 80 ° C., to obtain a reaction solution containing silver nanoparticles.
  • the subsequent purification treatment was performed in the same manner as in the preparation of the silver nanoparticle dispersion 1.
  • the average particle size and particle size distribution of silver nanoparticles in the obtained solution were measured by the method described in the evaluation method described later. As a result, the average particle diameter D1 was 50 nm, and the half width of the peak was 50 nm.
  • ⁇ Silver nanoparticle dispersion 3> In a 1-L separable flask having a flat stirring blade and a baffle, 8.4 g of DISPERBYK-190 and 265 g of ion-exchanged water were charged, and stirring was performed to dissolve DISPERBYK-190. Subsequently, 80 g of silver nitrate dissolved in 265 g of ion-exchanged water was charged into the separable flask while stirring. Furthermore, 80 g of ammonia water was added and stirring was performed, and then, the separable flask was put into a water bath, and heated and stirred until the temperature of the solution stabilized at 70 ° C. Thereafter, 209 g of dimethylaminoethanol was added to the separable flask, and stirring was further continued for 6 hours while keeping the temperature at 70 ° C., to obtain a reaction solution containing silver nanoparticles.
  • the subsequent purification treatment was performed in the same manner as in the preparation of the silver nanoparticle dispersion 1.
  • the average particle size and particle size distribution of silver nanoparticles in the obtained solution were measured by the method described in the evaluation method described later. As a result, the average particle diameter D1 was 70 nm, and the half width of the peak was 25 nm.
  • ⁇ Silver nanoparticle dispersion liquid 4> In a 1-L separable flask having a flat stirring blade and a baffle, 8.4 g of DISPERBYK-190 and 265 g of ion-exchanged water were charged, and stirring was performed to dissolve DISPERBYK-190. Subsequently, 80 g of silver nitrate dissolved in 265 g of ion-exchanged water was charged into the separable flask while stirring. Furthermore, 70 g of ammonia water was added and stirring was performed, and then, the separable flask was put into a water bath, and heated and stirred until the temperature of the solution stabilized at 70 ° C. Thereafter, 183 g of dimethylaminoethanol was added to the separable flask, and stirring was continued for 6 hours while keeping the temperature at 70 ° C. to obtain a reaction solution containing silver nanoparticles.
  • the subsequent purification treatment was performed in the same manner as in the preparation of the silver nanoparticle dispersion 1.
  • the average particle size and particle size distribution of silver nanoparticles in the obtained solution were measured by the method described in the evaluation method described later. As a result, the average particle diameter D1 was 60 nm, and the half width of the peak was 25 nm.
  • ⁇ Silver nanoparticle dispersion 7> In a 1 L separable flask having a flat stirring blade and a baffle, 8.6 g of DISPERBYK-190 and 269 g of ion exchanged water were charged, and stirring was performed to dissolve DISPERBYK-190. Subsequently, 55 g of silver nitrate dissolved in 269 g of ion-exchanged water was charged into the separable flask while stirring. Furthermore, 70 g of ammonia water was added and stirring was performed, then, the above separable flask was put into a water bath, and was heated and stirred until the temperature of the solution stabilized at 80 ° C. Thereafter, 144 g of dimethylaminoethanol was added to the separable flask, and stirring was continued for 6 hours while keeping the temperature at 80 ° C. to obtain a reaction solution containing silver nanoparticles.
  • the obtained reaction solution was placed in a stainless steel cup, and 2 L of ion exchanged water was further added, and then the pump was operated to perform ultrafiltration.
  • the solution in the stainless steel cup decreased, ion-exchanged water was again added, and purification was repeated until the conductivity of the filtrate became 100 ⁇ S / cm or less. Thereafter, the filtrate was concentrated to obtain a silver nanoparticle dispersion liquid 7 having a solid content of 30% by mass.
  • the ultrafiltration apparatus used was an ultrafiltration module AHP1010 (Asahi Kasei Co., Ltd., molecular weight cut off: 50000, number of membranes used: 400), and a tube pump (Masterflex Co., Ltd.) connected by a tygon tube. .
  • the average particle size and particle size distribution of silver nanoparticles in the obtained solution were measured by the method described in the evaluation method described later. As a result, the average particle diameter D1 was 25 nm, and the half width of the peak was 21 nm.
  • ⁇ Silver nanoparticle dispersion 8> In the preparation of silver nanoparticle dispersion 7, silver was similarly prepared except that the addition amount of silver nitrate was 67 g, the dispersant was 8.3 g, the ammonia water amount was 78 g, the dimethylaminoethanol amount was 211 g, and the stirring time was 4 hours. The nanoparticle dispersion liquid 8 was obtained. The D50 of the silver nanoparticles in the obtained silver nanoparticle dispersion liquid 45 was 45 nm, and the half-width of the particle size distribution was 30 nm.
  • silver nanoparticle dispersion 10 was prepared in the same manner as silver particulate dispersion 10 except that the amount of silver nitrate added was 40 g, the dispersant was 8.7 g, the amount of aqueous ammonia was 51 g, and the amount of dimethylaminoethanol was 105 g. Obtained.
  • the average particle diameter D1 of the silver nanoparticles in the obtained silver nanoparticle dispersion liquid 10 was 15 nm, and the half width of the peak was 22 nm.
  • ⁇ Silver nanoparticle dispersion liquid 12> In the preparation of silver nanoparticle dispersion 1, silver was similarly prepared except that the amount of silver nitrate added was 90 g, the dispersant was 7.4 g, the amount of aqueous ammonia was 137 g, the amount of dimethylaminoethanol was 189 g, and the stirring time was 6 hours. The nanoparticle dispersion liquid 12 was obtained. The average particle diameter D1 of the silver nanoparticles in the obtained silver nanoparticle dispersion liquid 12 was 85 nm, and the half width of the peak was 45 nm.
  • ⁇ Silver nanoparticle dispersion liquid 13> In the preparation of silver nanoparticle dispersion 1, silver was similarly prepared except that the amount of silver nitrate added was 90 g, the dispersant was 7.2 g, the amount of aqueous ammonia was 100 g, the amount of dimethylaminoethanol was 283 g, and the stirring time was 4 hours. The nanoparticle dispersion liquid 13 was obtained. The average particle diameter D1 of the silver nanoparticles in the obtained silver nanoparticle dispersion liquid 13 was 88 nm, and the half width of the peak was 140 nm.
  • ⁇ Silver nanoparticle dispersion liquid 14> In the preparation of silver nanoparticle dispersion 1, silver was similarly prepared except that the addition amount of silver nitrate was 55 g, the dispersant was 8.6 g, the amount of aqueous ammonia was 70 g, the amount of dimethylaminoethanol was 144 g, and the stirring time was 6 hours. The nanoparticle dispersion liquid 14 was obtained. The average particle diameter D1 of the silver nanoparticles in the obtained silver nanoparticle dispersion liquid 25 was 25 nm, and the half width of the peak was 21 nm.
  • the average particle size and particle size distribution of silver nanoparticles in the obtained solution were measured by the method described in the evaluation method described later. As a result, the average particle diameter D1 was 38 nm, and the half width of the maximum peak was 37 nm.
  • ⁇ Silver nanoparticle dispersion liquid 17> In the preparation of silver nanoparticle dispersion 1, silver was similarly prepared except that 70 g of added amount of silver nitrate, 7.6 g of dispersant, 89 g of ammonia water, 89 g of dimethylaminoethanol amount, and stirring time 6 hours. The nanoparticle dispersion liquid 17 was obtained. The average particle diameter D1 of the silver nanoparticles in the obtained silver nanoparticle dispersion liquid 17 was 53 nm, and the half width of the peak was 23 nm.
  • ⁇ Silver nanoparticle dispersion liquid 18> In the preparation of silver nanoparticle dispersion 1, silver was similarly prepared except that the amount of silver nitrate added was 83 g, the dispersant was 8.3 g, the amount of aqueous ammonia was 71 g, the amount of dimethylaminoethanol was 217 g, and the stirring time was 6 hours. The nanoparticle dispersion liquid 18 was obtained. The average particle diameter D1 of the silver nanoparticles in the obtained silver nanoparticle dispersion liquid was 75 nm, and the half width of the peak was 22 nm.
  • Emulsion resin particle dispersion 1 consisting of polyurethane having a nonvolatile content of about 20%. It was 40 nm when the average particle diameter D2 of the obtained emulsion resin particle was measured.
  • ⁇ Emulsion resin particle dispersion 2> In a four-necked flask equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet, 140 g of isopropyl alcohol as a solvent is charged and heated to 85 ° C., and 12.5 g of methacrylic acid is introduced while introducing nitrogen gas. A mixture of 60.5 g of methyl methacrylate and 23 g of 2-ethylhexyl acrylate and 4 g of a reaction initiator (“ABN-E” manufactured by Nippon Hydrazine Industry Co., Ltd.) was added dropwise over 2 hours. After dropping, polymerization was carried out for 2 hours while maintaining the same temperature, and then the solvent was distilled off under reduced pressure to obtain a water-soluble resin having a glass transition temperature of 50 ° C.
  • 96 g of the obtained water-soluble resin is pulverized and then added to 140 g of water in which an equivalent amount of ammonia and carboxyl groups contained in the water-soluble resin calculated from the monomer composition are dissolved and mixed, and heated at 80 ° C. It was dissolved to obtain an aqueous solution (A) of a polymeric emulsifier having a solid content concentration of 40%.
  • emulsion polymerization is carried out for 2.5 hours while maintaining the same temperature, and the resulting emulsion is diluted with water so that the solid concentration becomes 20%, and emulsion resin particle dispersion 2 (acrylic emulsion solution) is obtained. Obtained. It was 45 nm when the average particle diameter D2 of the emulsion resin particle in the obtained emulsion resin particle dispersion liquid 2 was measured.
  • ⁇ Emulsion resin particle dispersion 3> In a four-necked flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet pipe, 220 g of ion exchange water and 1.8 g of an emulsifier (Daiten Kogyo Seiyaku Co., Ltd. "Hitenol 18E”) ion exchange water The entire amount of the aqueous emulsifier solution dissolved in 8 g was charged, and after heating to 72 ° C.
  • aqueous solution (B) of this polymeric emulsifier was adjusted to 80 ° C., and 86 g of methyl methacrylate, 58 g of 2-ethylhexyl acrylate and 100 g of ion exchange water were dropped over 90 minutes. Thereafter, 7.2 g of a 2% aqueous ammonium persulfate solution was added dropwise over 30 minutes. Aging was carried out by maintaining the temperature for 90 minutes, and the obtained emulsion was diluted with water to a solid concentration of 20% to obtain emulsion resin particle dispersion 3 (acrylic emulsion solution). It was 15 nm when the average particle diameter D2 of the emulsion resin particle in the obtained emulsion resin particle dispersion liquid 3 was measured.
  • Solvent water PG Propylene glycol (boiling point: 188 ° C)
  • TEGME Triethylene glycol monomethyl ether (boiling point: 248 ° C)
  • a metallic gloss layer was formed on each of the substrates using an inkjet recording apparatus having a piezoelectric inkjet nozzle.
  • the inkjet recording apparatus includes an ink tank, an ink supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezoelectric inkjet head in this order from the upstream side to the downstream side through which ink flows. .
  • the ink jet head was driven under the condition that the droplet volume was 14 pl, the printing speed was 0.5 m / sec, the ejection frequency was 10.5 kHz, and the printing rate was 100%, and the ink droplets were ejected and landed on each substrate . After landing, it was dried at 60 ° C. for about 10 minutes to obtain an image-formed product.
  • the average particle diameter D1 and the particle size distribution of the metal nanoparticles (that is, the half width of the peak, the ratio of metal nanoparticles having a particle diameter of 40 nm or less, and the ratio of metal nanoparticles having a particle diameter of 60 nm or more) are observed by the following SEM It measured by the method based on. Further, the average particle diameter D2 of the emulsion resin particles was also measured by the same method. Specifically, it measured in the following procedures.
  • the half width, the ratio of metal nanoparticles having a particle diameter of 40 nm or less, and the ratio of metal nanoparticles having a particle diameter of 60 nm or more were also determined.
  • the particle diameter of the metal nanoparticles was determined as the particle diameter of the metal nanoparticles not containing the dispersing agent.
  • Standard deviation between reflectances was evaluated based on the following criteria.
  • the inks of Examples 1 to 13 containing water and metal nanoparticles having a volume equivalent average particle diameter D1 of 25 nm to 70 nm and a half width of 30 nm to 120 nm.
  • the standard deviation of the value every 20 nm of the reflectance measured in the wavelength range of 460 nm to 780 nm is as small as less than 4%, and the image formed product using the above has a reflectance of 460 nm and a reflectance of 660 nm. It can be seen that there is a small difference of 5% or less between them, and it shows a flat reflection spectrum like bulk metal.
  • Examples 1 to 8 and 10 in which the half width in the particle size distribution of the metal nanoparticles is 50 nm or more have standard deviations between reflectances of 2 compared with Examples 9 and 11 to 13 in which the half width is less than 50 nm.
  • a much flatter reflection spectrum was obtained, which is very small at less than 10%.
  • the reflection spectrum has a flatter shape, the original silver lustre with less coloring such as reddish or bluish can be recognized.
  • the proportion of metal nanoparticles having a particle diameter of 40 nm or less is 10% to 50% by volume
  • the proportion of metal nanoparticles having a particle diameter of 60 nm or more is 10% by volume or more based on the total volume of the metal nanoparticles.
  • the image-formed products of Examples 1 to 10 containing metal nanoparticles of 60 volume% or less have flatter reflection spectra than those of Examples 11 and 12 in which the proportion of metal nanoparticles having a particle diameter of 40 nm or less exceeds 50 volume%. Indicated.
  • the difference between the reflectance at a wavelength of 460 nm and the reflectance at a wavelength of 660 nm was 5%, but the images of Examples 1 to 10 In the reflection spectrum of the formation, this difference was very small, less than 3%.
  • the ratio of the metal nanoparticles having a particle diameter of 40 nm or less and the ratio of the metal nanoparticles having a particle diameter of 60 nm or more are within the above range
  • the difference between the reflectance at a wavelength of 460 nm and the reflectance at a wavelength of 660 nm was 0%, while the proportion of metal nanoparticles having a particle diameter of 60 nm or more exceeded 60% by volume.
  • the difference in reflectance was increased to 2%.
  • the image-formed product using the ink of Comparative Example 3 using metal nanoparticles having an average particle diameter of less than 25 nm has a large standard deviation of reflectance of 4% or more, and further, the reflectance at a wavelength of 460 nm is a reflectance at a wavelength of 660 nm It was higher than.
  • Such an image formed product has a bluish color tone. This is considered to be because the particle size distribution of the metal nanoparticles was biased to the small particle size side.
  • the image-formed product using the ink of Example 5 had a large standard deviation of reflectance of 4% or more, and further, the reflectance at a wavelength of 660 nm was higher than that at a wavelength of 460 nm. Such an image formed product has a reddish tone. This is considered to be because the particle size distribution was biased to the large particle size side.
  • Material B-1-1. Preparation of silver nanoparticle dispersion ⁇ silver nanoparticle dispersion 20> In a 1-L separable flask having a flat stirring blade and a baffle, 8.6 g of DISPERBYK-190 (manufactured by Bick Chemie Co., Ltd.) and 269 g of ion-exchanged water are charged and stirred to dissolve DISPERBYK-190. I did. Subsequently, 55 g of silver nitrate dissolved in 269 g of ion-exchanged water was charged into the separable flask while stirring.
  • the obtained reaction solution was placed in a stainless steel cup, and 2 L of ion exchanged water was further added, and then the pump was operated to perform ultrafiltration.
  • the solution in the stainless steel cup decreased, ion-exchanged water was again added, and purification was repeated until the conductivity of the filtrate became 100 ⁇ S / cm or less.
  • the filtrate was concentrated to obtain a silver nanoparticle dispersion 1 with a solid content of 30 wt%.
  • the ultrafiltration apparatus used was an ultrafiltration module AHP1010 (Asahi Kasei Co., Ltd., molecular weight cut off: 50000, number of membranes used: 400), and a tube pump (Masterflex Co., Ltd.) connected by a tygon tube. .
  • the obtained silver nanoparticle dispersion was observed by SEM to determine the volume particle size distribution. Specifically, it was carried out according to the following procedure. 1) After the dispersion was applied on a glass plate, it was vacuum degassed to evaporate the solvent components to obtain a sample. The obtained sample dispersion was subjected to SEM observation using a measuring apparatus JEOL JSM-7401F, and the particle sizes of arbitrary 300 silver nanoparticles were measured. 2) Based on the obtained measurement data, a particle size distribution based on volume is determined using image processing software Image J, and D50 (median diameter) thereof is defined as a volume equivalent average particle diameter (volume average particle diameter). In addition, the number of peaks and the half width were determined from the particle size distribution of silver nanoparticles.
  • the particle size of the silver nanoparticles was determined as the particle size of silver nano particles not containing the dispersing agent.
  • the average particle diameter of the silver nanoparticle dispersion liquid 20 was 25 nm, the volume particle size distribution was unimodal, and the half width was 21 nm.
  • Silver nanoparticle dispersion 21 In the preparation of the silver nanoparticle dispersion 1, the silver nanoparticle dispersion 21 was prepared in the same manner except that 70 g of the added amount of silver nitrate, 7.6 g of the dispersant, 89 g of ammonia water and 89 g of dimethylaminoethanol were changed. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion 2 were determined in the same manner as the silver nanoparticle dispersion 20 described above. As a result, the average particle size was 53 nm, the volume particle size distribution was unimodal, and the half width was 23 nm.
  • ⁇ Silver nanoparticle dispersion liquid 22> In the preparation of the silver nanoparticle dispersion liquid 20, the silver nanoparticle dispersion liquid 22 is similarly prepared except that the amount of addition of silver nitrate is 80 g, the dispersant is 7.2 g, the amount of aqueous ammonia is 102 g, and the amount of dimethylaminoethanol is 209 g. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 3 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle size was 70 nm, the volume particle size distribution was unimodal, and the half width was 20 nm.
  • the silver nanoparticle dispersion liquid 23 is similarly prepared except that the addition amount of silver nitrate is 63 g, the dispersant is 8.0 g, the ammonia water amount is 80 g, and the dimethylaminoethanol amount is 165 g. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 23 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle size was 40 nm, the volume particle size distribution was unimodal, and the half width was 23 nm.
  • a silver nanoparticle dispersion liquid 20 was prepared in the same manner except that 71 g of silver nitrate was added, 7.8 g of a dispersant, 7.8 g of ammonia water, 80 g of ammonia water, 223 g of dimethylaminoethanol, and the stirring time was 3 hours and 30 minutes. Thus, a silver nanoparticle dispersion 24 was obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 24 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle size was 60 nm, the volume particle size distribution was unimodal, and the half width was 35 nm.
  • the silver nanoparticle dispersion 25 is prepared in the same manner as the silver nanoparticle dispersion except that the amount of silver nitrate added is 83 g, the dispersant is 8.3 g, the amount of aqueous ammonia is 71 g, and the amount of dimethylaminoethanol is 217 g. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 6 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle diameter was 75 nm, the volume particle size distribution was unimodal, and the half width was 22 nm.
  • ⁇ Silver nanoparticle dispersion liquid 26> In the preparation of the silver nanoparticle dispersion liquid 20, the silver nanoparticle dispersion liquid 26 is similarly prepared except that the addition amount of silver nitrate is 40 g, the dispersant is 8.7 g, the ammonia water amount is 51 g, and the dimethylaminoethanol amount is 105 g. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 26 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle size was 15 nm, the volume particle size distribution was unimodal, and the half width was 22 nm.
  • ⁇ Silver nanoparticle dispersion liquid 27> In the preparation of the silver nanoparticle dispersion 20, silver was similarly prepared except that the addition amount of silver nitrate was 67 g, the dispersant was 8.3 g, the ammonia water amount was 78 g, the dimethylaminoethanol amount was 211 g, and the stirring time was 4 hours. The nanoparticle dispersion liquid 27 was obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 27 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle size was 45 nm, the volume particle size distribution was unimodal, and the half width was 30 nm.
  • the silver nanoparticle dispersion 28 was prepared in the same manner as in the preparation of the silver nanoparticle dispersion 1, except that the amount of silver nitrate added was 15 g, the dispersant was 6.0 g, the amount of aqueous ammonia was 25 g, and the amount of dimethylaminoethanol was 24 g. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 28 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle size was 30 nm, the volume particle size distribution was unimodal, and the half width was 9 nm.
  • the silver nanoparticle dispersion liquid 29 is similarly prepared except that the addition amount of silver nitrate is 40 g, the dispersant is 9.4 g, the ammonia water amount is 51 g, and the dimethylaminoethanol amount is 105 g. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion 29 were determined in the same manner as the silver nanoparticle dispersion 20 described above. As a result, the average particle size was 15 nm, the volume particle size distribution was unimodal, and the half width was 20 nm.
  • Silver nanoparticle dispersion liquid 30 In the preparation of the silver nanoparticle dispersion 20, silver was similarly prepared except that the addition amount of silver nitrate was 60 g, the dispersant was 8.6 g, the ammonia water amount was 88 g, the dimethylaminoethanol amount was 126 g, and the stirring time was 9 hours. The nanoparticle dispersion liquid 30 was obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 30 were determined.
  • the average particle size was 35 nm
  • the volume particle size distribution was unimodal
  • the half width was 15 nm.
  • the silver nanoparticle dispersion liquid 31 is similarly prepared except that the addition amount of silver nitrate is 5 g, the dispersant is 2.0 g, the ammonia water amount is 10 g, and the dimethylaminoethanol amount is 8 g. Obtained.
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 31 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle diameter was 20 nm, the volume particle size distribution was unimodal, and the half width was 3 nm.
  • the obtained reaction solution was placed in a stainless steel cup, and 2 L of ion exchanged water was further added, and then the pump was operated to perform ultrafiltration.
  • the solution in the stainless steel cup decreased, ion-exchanged water was again added, and purification was repeated until the conductivity of the filtrate became 100 ⁇ S / cm or less. Thereafter, the filtrate was concentrated to obtain a silver nanoparticle dispersion liquid 32 having a solid content of 30 wt%.
  • the ultrafiltration apparatus used was an ultrafiltration module AHP1010 (Asahi Kasei Co., Ltd., molecular weight cut off: 50000, number of membranes used: 400), and a tube pump (Masterflex Co., Ltd.) connected by a tygon tube. .
  • the average particle diameter, the number of peaks, and the half width of the silver nanoparticle dispersion liquid 32 were determined in the same manner as the silver nanoparticle dispersion liquid 20 described above. As a result, the average particle size of the silver nanoparticles was 55 nm, the volume particle size distribution was unimodal, and the half width was 4 nm.
  • the silver nanoparticle dispersion liquid A was obtained by mixing the silver nanoparticle dispersion liquids 20, 21 and 22 in a weight ratio of 3: 3: 4, and adjusting the volume particle size distribution.
  • three types of particle dispersions were mixed, since there was overlap of peaks, it was bimodal.
  • ⁇ Silver nanoparticle dispersion liquid B> The silver nanoparticle dispersion liquids 22 and 23 were mixed at a weight ratio of 1: 1 to obtain a silver nanoparticle dispersion liquid B having adjusted volume particle size distribution.
  • ⁇ Silver nanoparticle dispersion liquid C> The silver nanoparticle dispersion liquids 20 and 24 were mixed at a weight ratio of 2: 5 to adjust the volume particle size distribution, to obtain a silver nanoparticle dispersion liquid C.
  • ⁇ Silver nanoparticle dispersion liquid D> The silver nanoparticle dispersion liquids 20, 21, and 25 were mixed at a weight ratio of 3: 3: 4, and the volume particle size distribution was adjusted, to obtain a silver nanoparticle dispersion liquid D.
  • the silver nanoparticle dispersion liquid E was obtained by mixing the silver nanoparticle dispersion solutions 25, 26, and 27 in a weight ratio of 1: 1: 3, and adjusting the volume particle size distribution.
  • three types of particle dispersions were mixed, since there was overlap of peaks, it was bimodal.
  • ⁇ Silver nanoparticle dispersion liquid F> The silver nanoparticle dispersion liquids 24 and 28 were mixed at a weight ratio of 2: 5 to adjust the volume particle size distribution, to obtain a silver nanoparticle dispersion liquid F.
  • the silver nanoparticle dispersion liquid 21 was used as a silver nanoparticle dispersion liquid G without being mixed with another dispersion liquid.
  • ⁇ Silver nanoparticle dispersion liquid H> The silver nanoparticle dispersion liquids 29 and 30 were mixed at a weight ratio of 3: 2, and the volume particle size distribution was adjusted to obtain a silver nanoparticle dispersion liquid H.
  • ⁇ Silver nanoparticle dispersion I> The silver nanoparticle dispersion liquids 31 and 32 were mixed at a weight ratio of 1: 1 to obtain a silver nanoparticle dispersion liquid I having adjusted volume particle size distribution.
  • ⁇ Silver nanoparticle dispersion liquid J> The silver nanoparticle dispersion liquids 20 and 21 were mixed at a weight ratio of 1: 9 to adjust the volume particle size distribution, to obtain a silver nanoparticle dispersion liquid J.
  • Emulsion resin particle dispersion 1 consisting of polyurethane having a nonvolatile content of about 20%. It was 40 nm when the average particle diameter of the obtained emulsion resin particle was measured similarly to the said silver nanoparticle dispersion liquid 1.
  • ⁇ Emulsion resin particle dispersion 2> In a four-necked flask equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet, 140 g of isopropyl alcohol as a solvent is charged and heated to 85 ° C., and 12.5 g of methacrylic acid is introduced while introducing nitrogen gas. A mixture of 60.5 g of methyl methacrylate and 23 g of 2-ethylhexyl acrylate and 4 g of a reaction initiator (“ABN-E” manufactured by Nippon Hydrazine Industry Co., Ltd.) was added dropwise over 2 hours. After dropping, polymerization was carried out for 2 hours while maintaining the same temperature, and then the solvent was distilled off under reduced pressure to obtain a water-soluble resin having a glass transition temperature of 50 ° C.
  • 96 g of the obtained water-soluble resin is pulverized and then added to 140 g of water in which an equivalent amount of ammonia and carboxyl groups contained in the water-soluble resin calculated from the monomer composition are dissolved and mixed, and heated at 80 ° C. It was dissolved to obtain an aqueous solution (A) of a polymeric emulsifier having a solid content concentration of 40%.
  • emulsion polymerization is performed for 2.5 hours while maintaining the same temperature, and the obtained emulsion is diluted with water so that the solid concentration becomes 20%, and emulsion resin particle dispersion 2 (acrylic emulsion solution) is obtained. Obtained.
  • the average particle diameter of the emulsion resin particles in the obtained emulsion resin particle dispersion 2 was measured in the same manner as the silver nanoparticle dispersion 1 and was 45 nm.
  • Solvent water PG Propylene glycol (boiling point: 188 ° C)
  • TEGME Triethylene glycol monomethyl ether (boiling point: 248 ° C)
  • a metallic gloss layer was formed on each of the substrates using an inkjet recording apparatus having a piezoelectric inkjet nozzle.
  • the inkjet recording apparatus includes an ink tank, an ink supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezoelectric inkjet head in this order from the upstream side to the downstream side through which ink flows. .
  • the ink jet head was driven under the condition that the droplet volume was 14 pl, the printing speed was 0.5 m / sec, the ejection frequency was 10.5 kHz, and the printing rate was 100%, and the ink droplets were ejected and landed on each substrate . After landing, Examples 1 to 11 and Comparative Examples 1 to 3 were dried at 60 ° C. for about 10 minutes, and Comparative Example 4 was dried at 120 ° C. for about 10 minutes to obtain an image-formed product.
  • ⁇ Standard deviation of reflectance> The reflectance of each wavelength of every 20 nm was measured for the range of 460 nm to 780 nm using a spectrophotometer U4100, the standard deviation between the reflectances was calculated, and the evaluation was made based on the following criteria. :: Standard deviation of reflectance is less than 2% ⁇ : Standard deviation of reflectance is 2% or more and less than 3% ⁇ : Standard deviation of reflectance is 3% or more and less than 4% ⁇ : Standard deviation of reflectance is 4% or more ⁇ or more was evaluated as having practicality.
  • the sheet resistance value of the metallic gloss layer was measured by a four-terminal method using a volume resistivity measuring device Lorester manufactured by Mitsubishi Chemical and a PSP type measuring probe.
  • the above resistance indicator is 1.0 ⁇ 10 6.0 ⁇ / sq was measurement limit.
  • Example 14 in which the half value width of all the peaks is 10 nm or more and the ratio of the small diameter side peak particle diameter to the large diameter side peak particle diameter of two adjacent peaks is 0.3 or more and 0.8 or less.
  • the standard deviation between the reflectances is very small, less than 2%, compared to Example 21 in which the half width is less than 10 nm and Example 20 in which the peak particle size ratio is less than 0.3.
  • a flat reflection spectrum was obtained.
  • the sheet resistance of the metallic gloss layer is greater than 1 ⁇ 10 5 ⁇ / sq, but the percentage of fused silver nanoparticles is 31% (ie, the percentage of non-fused silver nanoparticles is 69%)
  • the image-formed product of Comparative Example 8 in which the standard deviation between reflectances was as large as 4% or more, the shape of the reflection spectrum was not flat.
  • the percentage of fused silver nanoparticles is 83% (that is, the percentage of non-fused silver nanoparticles is 17%)
  • the sheet resistance of the metallic gloss layer is 1 ⁇ 10 5 ⁇ / ⁇ .
  • the image formed product of Comparative Example 9 which is less than or equal to sq. has a very small standard deviation between reflectances of less than 2%.
  • the ink containing the metal nanoparticle which can form the image which has the original color tone of the said metal in which expression of the specific color tone was suppressed can be provided.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Ink Jet Recording Methods And Recording Media Thereof (AREA)
  • Inks, Pencil-Leads, Or Crayons (AREA)
  • Ink Jet (AREA)
  • Pigments, Carbon Blacks, Or Wood Stains (AREA)

Abstract

La présente invention concerne une encre contenant des nanoparticules métalliques, qui est apte à former une image qui est supprimée lors du développement d'une ombre spécifique, présentant ainsi la tonalité de couleur d'origine du métal. Concernant une première encre selon la présente invention, les nanoparticules métalliques présentent un diamètre moyen des particules (D1) allant de 25 nm (inclus) à 70 nm (inclus), tout en ayant une valeur de demi-largeur de pic allant de 30 nm (inclus) à 120 nm (inclus) dans la répartition des tailles de particules selon le volume. Concernant une seconde encre selon la présente invention, les nanoparticules métalliques sont des nanoparticules d'argent ; les nanoparticules d'argent ont au moins deux pics, à savoir un premier pic qui présente un diamètre des particules maximal dans la plage de 5 nm (inclus) à 45 nm (exclus) et un second pic qui présente un diamètre des particules maximal dans la plage de 45 nm (inclus) à 100 nm (inclus) dans la répartition des tailles de particules selon le volume ; et les valeurs de demi-largeur respectives du premier pic et du second pic sont supérieures ou égales à 5 nm, indépendamment. La présente invention concerne également un article ayant une image formée et un procédé de formation d'image, qui font chacun appel à cette encre.
PCT/JP2018/034494 2017-09-27 2018-09-18 Encre, article ayant une image formée, et procédé de formation d'image WO2019065371A1 (fr)

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JP2015501334A (ja) * 2011-09-30 2015-01-15 クラリアント・インターナシヨナル・リミテツド マイクロコンタクト印刷に使用するための金属ベースのナノパーティクルを含む水性インキ調合物
JP2017048366A (ja) * 2015-07-16 2017-03-09 ダウ グローバル テクノロジーズ エルエルシー 安定化ナノ粒子、及び安定化ナノ粒子の分散、及び適用方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004285106A (ja) * 2003-03-19 2004-10-14 Toppan Forms Co Ltd 金属ナノ微粒子を含む塗工液、シート
JP2007113090A (ja) * 2005-10-21 2007-05-10 Fujifilm Corp 金属微粒子分散液の製造方法、着色組成物、インク、感光性転写材料、遮光画像付き基板、カラーフィルター、液晶表示素子、及び液晶表示装置
JP2010507727A (ja) * 2006-10-25 2010-03-11 バイエル・マテリアルサイエンス・アクチェンゲゼルシャフト 銀含有水性処方物および導電性または反射性コーティングを製造するためのその使用
JP2009269935A (ja) * 2008-04-30 2009-11-19 Sumitomo Metal Mining Co Ltd 金色系金属光沢を有する銀膜
JP2011241240A (ja) * 2010-05-14 2011-12-01 Seiko Epson Corp インク組成物および記録方法
JP2012122040A (ja) * 2010-12-10 2012-06-28 Seiko Epson Corp 導体パターン形成用インク、導体パターンおよび配線基板
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JP2015501334A (ja) * 2011-09-30 2015-01-15 クラリアント・インターナシヨナル・リミテツド マイクロコンタクト印刷に使用するための金属ベースのナノパーティクルを含む水性インキ調合物
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