Classifications

• • 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
  • C09D17/00—Pigment pastes, e.g. for mixing in paints
  • C09D17/004—Pigment pastes, e.g. for mixing in paints containing an inorganic pigment
  • C09D17/006—Metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/05—Metallic powder characterised by the size or surface area of the particles
  • B22F1/054—Nanosized particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/05—Metallic powder characterised by the size or surface area of the particles
  • B22F1/054—Nanosized particles
  • B22F1/0545—Dispersions or suspensions of nanosized particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
  • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
  • B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
• • 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
  • B41M5/0023—Digital printing methods characterised by the inks used
• • 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
  • C09D11/033—Printing inks characterised by features other than the chemical nature of the binder characterised by the solvent
• • 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
  • C09D11/02—Printing inks
  • C09D11/10—Printing inks based on artificial resins
  • C09D11/106—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
  • C09D11/10—Printing inks based on artificial resins
  • C09D11/106—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C09D11/107—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from unsaturated acids or derivatives thereof
• • 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
• • 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
  • C09D11/324—Inkjet printing inks characterised by colouring agents containing carbon black
  • C09D11/326—Inkjet printing inks characterised by colouring agents containing carbon black characterised by the pigment dispersant
• • 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
  • C09D11/52—Electrically conductive inks
• • 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
  • C09D17/00—Pigment pastes, e.g. for mixing in paints
  • C09D17/001—Pigment pastes, e.g. for mixing in paints in aqueous medium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2301/00—Metallic composition of the powder or its coating
  • B22F2301/25—Noble metals, i.e. Ag Au, Ir, Os, Pd, Pt, Rh, Ru
  • B22F2301/255—Silver or gold
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2304/00—Physical aspects of the powder
  • B22F2304/05—Submicron size particles
  • B22F2304/054—Particle size between 1 and 100 nm
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y40/00—Manufacture or treatment of nanostructures

Definitions

• the present invention relates to an aqueous metal fine particle dispersion and a method for producing the same, a metallic printing ink containing the aqueous metal fine particle dispersion, and a metallic printing method using the ink.
• Metal fine particles are expected to be developed for a wide variety of industrial applications because of the variety of functions and physical properties that are exhibited by using fine metal particles in a nano size.
• various methods for producing metal fine particles are being studied.
• a wet method such as a method of reducing a metal ion eluted from a metal compound in a liquid and a method of extracting a metal atom by thermal decomposition of a metal complex is known.
• the method using a metal complex requires a heat treatment at a high temperature, and the reducing solution used for the reduction of the metal complex has a problem related to the removal of residual organic substances and the like, and industrially practical production methods have been studied. .
• JP-A-2017-2219 provides a composition for forming a silver mirror film layer which can form a silver mirror film layer at normal temperature and does not generate harmful components or corrosive by-products.
• Patent Document 1 provides a composition for forming a silver mirror film layer which can form a silver mirror film layer at normal temperature and does not generate harmful components or corrosive by-products.
• a polymer dispersant in an alcohol solvent
• ultrasonic waves are introduced into the alcohol solution.
• a composition for forming a silver mirror film layer comprising a dispersion solution of silver nanoparticles obtained by irradiation.
• Patent Document 2 discloses a method for providing metal colloid particles having few coarse particles and containing metal nanoparticles at a high concentration and having excellent long-term storage stability.
• Metal colloid particles composed of particles and a protective colloid covering the metal nanoparticles, wherein the protective colloid is composed of an organic compound having a carboxyl group and a polymer dispersant. Etc. are described.
• the present invention is an aqueous metal fine particle dispersion containing metal fine particles a dispersed in a dispersant B,
• the dispersant B has a constitutional unit derived from a hydrophobic monomer (b-1), a constitutional unit derived from a monomer (b-2) having a carboxy group, and a constitution derived from a monomer (b-3) having a polyalkylene glycol segment.
• the cumulant average particle diameter of the metal fine particles a is 2 nm or more and 50 nm or less;
• the present invention relates to an aqueous metal fine particle dispersion having a metal concentration of 30% by mass or more and 80% by mass or less in the metal fine particle dispersion.
• the metal concentration of the obtained dispersion is low, and aggregation of metal fine particles occurs when a dispersion having a high metal concentration is to be obtained.
• metals such as silver have a large specific gravity and poor dispersion stability, and it has been difficult to obtain an aqueous dispersion containing finely dispersed metal fine particles at a high concentration.
• the metal fine particles are contained at a high concentration, aggregation of the metal fine particles is liable to occur, and the storage stability of the metal fine particles as an aqueous dispersion is not sufficient in the techniques of Patent Documents 1 and 2.
• the present invention contains an aqueous metal fine particle dispersion containing finely dispersed metal fine particles at a high concentration, and has excellent storage stability, a method for producing the same, a metallic printing ink containing the aqueous metal fine particle dispersion, and It is an object to provide a metallic printing method using ink.
• the present inventors have focused on the fact that by dispersing the metal fine particles with a dispersant containing a vinyl polymer containing a structural unit derived from a specific monomer in a predetermined amount, the aggregation of the metal fine particles can be controlled. It has been found that an aqueous pigment dispersion containing the metal particles obtained at a high concentration and having excellent storage stability can be obtained.
• an aqueous metal fine particle dispersion containing metal fine particles a dispersed with a dispersant B has a constitutional unit derived from a hydrophobic monomer (b-1), a constitutional unit derived from a monomer (b-2) having a carboxy group, and a constitution derived from a monomer (b-3) having a polyalkylene glycol segment.
• the cumulant average particle diameter of the metal fine particles a is 2 nm or more and 50 nm or less;
• An ink for metallic printing comprising the aqueous metal fine particle dispersion according to [1].
• the aqueous metal fine particle dispersion (hereinafter, also referred to as “metal fine particle dispersion” or “dispersion”) of the present invention contains metal fine particles a (hereinafter, also referred to as “metal fine particles a”) dispersed with a dispersant B.
• the dispersant B is a monomer (b-2) having a carboxy group and a structural unit derived from a hydrophobic monomer (b-1) (hereinafter, also referred to as "monomer (b-1)").
• polymer (b-2) (Hereinafter also referred to as “monomer (b-2)”), and a configuration derived from monomer (b-3) having a polyalkylene glycol segment (hereinafter also referred to as “monomer (b-3)”) Containing 85% by mass or more of a vinyl-based polymer b containing a unit (hereinafter, also referred to as “polymer b”), the average particle diameter of the cumulant of the metal fine particles a being 2 nm or more and 50 nm or less, and the metal concentration in the metal fine particle dispersion. 0 is% by weight to 80% by weight.
• the metal fine particle dispersion of the present invention is obtained by dispersing metal fine particles a in an aqueous medium.
• the form of the metal fine particles a is not particularly limited, as long as the particles are formed by at least the metal fine particles and the dispersant B.
• a particle form in which metal fine particles are included in dispersant B a particle form in which metal fine particles are uniformly dispersed in dispersant B, a particle form in which metal fine particles are exposed on the particle surface of dispersant B, and the like are included.
• aqueous means that water occupies the largest proportion in an aqueous medium.
• the metal fine particle dispersion of the present invention contains metal fine particles dispersed with a dispersant, and the dispersant is derived from a structural unit derived from a hydrophobic monomer (b-1) and a monomer (b-2) having a carboxy group. And 85% by mass or more of a vinyl polymer b containing a structural unit derived from the monomer (b-3) having a polyalkylene glycol segment.
• the structural unit derived from the monomer (b-2) gives the polymer b a coordinating ability to a metal through a carboxy group.
• the structural unit derived from the monomer (b-1) is unstable in an aqueous medium because of its hydrophobicity, but is aggregated on the metal surface because it is slightly stable, and as a result, is densely packed on the surface of the metal fine particles. Collect.
• the polyalkylene glycol segment of the structural unit derived from the monomer (b-3) spreads in the aqueous medium, and the dispersion stability of the metal fine particles is improved by the steric repulsion.
• the metal (metal atom) constituting the metal fine particles a is a Group 4 transition metal such as titanium or zirconium, a Group 5 transition metal such as vanadium or niobium, or a Group 6 transition metal such as chromium, molybdenum or tungsten. , Manganese, technetium, rhenium and other Group 7 transition metals; iron, ruthenium and other Group 8 transition metals; cobalt, rhodium, iridium and other Group 9 transition metals; Group 11 transition metals such as copper, silver, and gold; Group 12 transition metals such as zinc and cadmium; and Group 13 metals such as aluminum, gallium, and indium; germanium, tin, and lead.
• a Group 4 transition metal such as titanium or zirconium
• a Group 5 transition metal such as vanadium or niobium
• a Group 6 transition metal such as chromium, molybdenum or tungsten.
• Group 14 metals As the metal constituting the metal fine particles a, one kind may be used as a single metal or two or more kinds may be used in combination as an alloy. Among them, preferred are transition metals of Groups 4 to 11 in the fourth to sixth periods, more preferred are noble metals such as copper, gold, silver, platinum and palladium, and further preferred are gold, silver and copper. It is at least one kind selected, and still more preferably silver.
• Dispersant B comprises a structural unit derived from a hydrophobic monomer (b-1), a structural unit derived from a monomer (b-2) having a carboxy group, and a monomer (b-3) having a polyalkylene glycol segment. Contains 85% by mass or more of a vinyl-based polymer b containing a structural unit derived from the polymer. Thereby, the aggregation of the metal fine particles in the aqueous medium is controlled, the dispersion stability of the metal fine particles is improved, the finely dispersed metal fine particles can be contained at a high concentration, and the storage stability of the dispersion is also improved. I do.
• the polymer b is a raw material monomer containing a hydrophobic monomer (b-1), a monomer having a carboxy group (b-2), and a monomer having a polyalkylene glycol segment (b-3) (hereinafter, also simply referred to as “raw material monomer”). ) Is copolymerized.
• the polymer b may be any of a block copolymer, a random copolymer, and an alternating copolymer.
• the monomer (b-1) is used as a monomer component of the polymer b from the viewpoint of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion.
• “hydrophobic” means that when the monomer is dissolved in 100 g of ion-exchanged water at 25 ° C. until the monomer is saturated, the dissolved amount is less than 10 g.
• the amount of the monomer (b-1) to be dissolved is preferably 5 g or less, more preferably 1 g or less, from the viewpoint of miniaturization and high concentration of the metal fine particles and from the viewpoint of improving the storage stability of the dispersion.
• the monomer (b-1) is preferably at least one selected from an aromatic group-containing monomer and a (meth) acrylate having a hydrocarbon group derived from an aliphatic alcohol.
• “(meth) acrylate” is at least one selected from acrylates and methacrylates.
• the “(meth) acrylate” below is also synonymous.
• the aromatic group-containing monomer is preferably a vinyl monomer having an aromatic group having 6 to 22 carbon atoms, which may have a substituent containing a hetero atom, and more preferably a styrene monomer and an aromatic monomer. At least one selected from group-containing (meth) acrylates.
• the molecular weight of the aromatic group-containing monomer is preferably less than 500.
• the styrene monomer include styrene, ⁇ -methylstyrene, 2-methylstyrene, 4-vinyltoluene (4-methylstyrene), divinylbenzene and the like, and styrene and ⁇ -methylstyrene are preferred.
• aromatic group-containing (meth) acrylate phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate and the like are preferable, and benzyl (meth) acrylate is more preferable.
• the (meth) acrylate having a hydrocarbon group derived from an aliphatic alcohol preferably has a hydrocarbon group derived from an aliphatic alcohol having 1 to 22 carbon atoms.
• (Meth) acrylate having a linear alkyl group such as stearyl (meth) acrylate; isopropyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, isopentyl (meth) acrylate, isooctyl (meth) acrylate, Having a branched
• (meth) acrylates having an alicyclic alkyl group such as cyclohexyl (meth) acrylate. Among them, those having an alkyl group having 6 to 10 carbon atoms are more preferable.
• the monomer (b-1) one type may be used alone, or two or more types may be used in combination.
• the monomer (b-1) is preferably an aromatic group-containing monomer, more preferably a styrene-based monomer, from the viewpoint of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion. And more preferably at least one selected from styrene, ⁇ -methylstyrene, 2-methylstyrene and 4-vinyltoluene (4-methylstyrene), and even more preferably at least one selected from styrene and ⁇ -methylstyrene.
• styrene-based monomer from the viewpoint of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion.
• at least one selected from styrene, ⁇ -methylstyrene, 2-methylstyrene and 4-vinyltoluene (4-methylstyrene) and even more preferably at least one selected from styrene and ⁇ -methyl
• the monomer (b-2) is used as a monomer component of the polymer b from the viewpoint of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion.
• the carboxy group contained in the monomer (b-2) also includes a carboxy group (—COOM) exhibiting acidity by dissociation and release of a hydrogen ion, or a dissociated ion form thereof (—COO ⁇ ).
• M represents a hydrogen atom, an alkali metal, ammonium or organic ammonium.
• the monomer (b-2) include unsaturated monocarboxylic acids such as (meth) acrylic acid, crotonic acid, and 2-methacryloyloxymethylsuccinic acid; maleic acid, itaconic acid, fumaric acid, citraconic acid, and the like. And the like.
• unsaturated dicarboxylic acid may be an anhydride.
• one kind of the monomer (b-2) may be used alone, or two or more kinds may be used in combination.
• the monomer (b-2) is preferably at least one selected from (meth) acrylic acid and maleic acid from the viewpoints of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion. is there.
• (meth) acrylic acid means at least one selected from acrylic acid and methacrylic acid.
• (meth) acrylic acid” is also synonymous.
• the monomer (b-3) is used as a monomer component of the polymer b from the viewpoint of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion.
• the monomer (b-3) is a monomer capable of introducing a polyalkylene glycol segment as a side chain of the polymer b, from the viewpoint of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion. preferable.
• Examples of the monomer include polyalkylene glycol (meth) acrylate, alkoxy polyalkylene glycol (meth) acrylate, and phenoxyalkylene glycol (meth) acrylate.
• the monomer (b-3) one type may be used alone, or two or more types may be used in combination.
• the monomer (b-3) is preferably at least one selected from polyalkylene glycol (meth) acrylate and alkoxy polyalkylene glycol (meth) acrylate, and more preferably alkoxy polyalkylene glycol (meth) acrylate.
• the alkoxy group of the alkoxypolyalkylene glycol (meth) acrylate preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms.
• alkoxy polyalkylene glycol (meth) acrylate examples include methoxy polyalkylene glycol (meth) acrylate, ethoxy polyalkylene glycol (meth) acrylate, propoxy polyalkylene glycol (meth) acrylate, butoxy polyalkylene glycol (meth) acrylate, and octoxy. And polyalkylene glycol (meth) acrylate.
• the polyalkylene glycol segment of the monomer (b-3) preferably contains a unit derived from an alkylene oxide having 2 to 4 carbon atoms.
• alkylene oxide examples include ethylene oxide, propylene oxide, and butylene oxide.
• the number of units derived from alkylene oxide in the polyalkylene glycol segment is preferably 2 or more, more preferably 5 or more, still more preferably 10 or more, and preferably 100 or less, more preferably 70 or less, and further preferably 50 or less.
• the polyalkylene glycol segment is a copolymer containing a unit derived from ethylene oxide and a unit derived from propylene oxide, from the viewpoint of miniaturization and high concentration of metal fine particles, and from the viewpoint of improving the storage stability of the dispersion. Is preferred.
• the molar ratio [EO / PO] between the ethylene oxide units (EO) and the propylene oxide units (PO) is preferably at least 60/40, more preferably at least 65/35, even more preferably at least 70/30, and It is preferably at most 90/10, more preferably at most 85/15, even more preferably at most 80/20.
• the copolymer containing a unit derived from ethylene oxide and a unit derived from propylene oxide may be any of a block copolymer, a random copolymer, and an alternating copolymer.
• the content of the monomers (b-1) to (b-3) in the raw material monomer (content as an unneutralized amount; the same applies hereinafter) or the monomers (b-1) to The content of the structural unit derived from (b-3) is as follows from the viewpoint of miniaturization and high concentration of the metal fine particles and from the viewpoint of improving the storage stability of the dispersion.
• the content of the monomer (b-1) is preferably at least 50 mol%, more preferably at least 60 mol%, still more preferably at least 65 mol%, and preferably at most 90 mol%, more preferably at least 85 mol%. %, More preferably 80% by mole or less.
• the content of the monomer (b-2) is preferably at least 5 mol%, more preferably at least 10 mol%, still more preferably at least 15 mol%, and preferably at most 40 mol%, more preferably at least 35 mol%. %, More preferably 30 mol% or less.
• the content of the monomer (b-3) is preferably at least 1 mol%, more preferably at least 5 mol%, still more preferably at least 7 mol%, and preferably at most 30 mol%, more preferably at least 20 mol%. %, More preferably 15 mol% or less.
• the polymer b is a structural unit derived from a styrene monomer as the monomer (b-1), a structural unit derived from (meth) acrylic acid and maleic acid as the monomer (b-2), and an alkoxypolyalkylene as the monomer (b-3). It is preferable to include a structural unit derived from glycol (meth) acrylate.
• a polymer synthesized by a known method may be used, or a commercially available product may be used.
• Commercially available products of the polymer b include DISPERBYK-2015 and 190 available from BYK.
• the number average molecular weight of the polymer b is preferably at least 1,000, more preferably at least 2,000, still more preferably at least 3,000, and preferably at most 100,000, more preferably at most 50,000, More preferably, it is 30,000 or less, still more preferably 10,000 or less, and still more preferably 7,000 or less.
• the number average molecular weight is measured by the method described in Examples.
• the acid value of the polymer b is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, further preferably 20 mgKOH / g or more, and preferably 200 mgKOH / g or less, more preferably 100 mgKOH / g or less. Preferably it is 50 mgKOH / g or less, still more preferably 30 mgKOH / g or less.
• the acid value of the polymer b is measured by the method described in the examples.
• Dispersant B may contain other dispersants other than polymer b.
• Other dispersants include polymer dispersants other than polymer b, low molecular weight dispersants having a carboxy group, and the like.
• the polymer dispersant other than the polymer b include a polymer dispersant having a nonionic group such as a hydroxy group, an amino group, an amide group, and an oxyalkylene group; and having an anionic property such as a carboxy group, a sulfonic acid group, and a phosphate group. And a polymer dispersant.
• polymer dispersant having a nonionic group examples include polyvinyl alcohol, polyvinylpyrrolidone, polyallylamine, polyethyleneimine, and polyacrylamide.
• polymer dispersant having an anionic group examples include condensation polymers such as polyurethane and polyester; and vinyl polymers such as acrylic resin, styrene resin, styrene-acrylic resin, and acrylic silicone resin.
• the number average molecular weight of the polymer dispersant other than the polymer b, preferably a polymer dispersant having an anionic group such as a carboxy group or a nonionic group, is in the same range as the number average molecular weight of the polymer b. Is preferred.
• the number average molecular weight of the polymer dispersant is also measured in the same manner as in the polymer b by the method described in the examples.
• the low molecular weight dispersant examples include an aliphatic (poly) carboxylic acid having 1 to 24 carbon atoms and an aliphatic hydroxycarboxylic acid having 2 to 34 carbon atoms.
• the molecular weight of the low molecular weight dispersant is preferably 100 or more, more preferably 200 or more, and preferably less than 1,000, more preferably 800 or less, and even more preferably 600 or less.
• an appropriately synthesized dispersant may be used, or a commercially available product may be used.
• the content of the polymer b in the dispersant B is 85% by mass or more, and preferably 90% by mass or more, from the viewpoint of miniaturization and high concentration of the metal fine particles and from the viewpoint of improving the storage stability of the dispersion. , More preferably 95% by mass or more, and preferably 100% by mass or less, and further preferably 100% by mass.
• the dispersant B is present in the metal fine particle dispersion in the form in which the dispersant B is adsorbed on the metal fine particles, the metal fine particle inclusion (capsule) in which the dispersant B contains the metal fine particles, and the metal fine particles.
• the dispersant B is not adsorbed. From the viewpoint of dispersion stability of the metal fine particles, a mode in which the metal fine particles are contained in the dispersant B is preferable, and a state in which the metal fine particles are contained in the metal fine particles is more preferable.
• the mass ratio of the dispersant B to the total amount of the dispersant B and the metal in the metal fine particle dispersion is preferably 0.01 or more from the viewpoint of miniaturization of the metal fine particles. It is more preferably at least 0.03, even more preferably at least 0.05, and from the viewpoint of improving the dispersion stability of the metal fine particles, improving the storage stability of the dispersion, and increasing the concentration of the metal fine particles. Therefore, it is preferably 0.3 or less, more preferably 0.2 or less, and still more preferably 0.1 or less.
• the mass ratio [dispersant B / (dispersant B + metal)] is calculated from the masses of the dispersant B and the metal measured by the method described in the Examples using a differential thermogravimetric analyzer (TG / DTA). Is calculated.
• the mass ratio of the polymer b to the total amount of the polymer b and the metal in the metal fine particle dispersion is preferable from the viewpoint of miniaturization of the metal fine particles. Is 0.01 or more, more preferably 0.03 or more, and still more preferably 0.05 or more, and a viewpoint of improving the dispersion stability of the metal fine particles and improving the storage stability of the dispersion, and the metal fine particles. From the viewpoint of increasing the concentration of, it is preferably 0.3 or less, more preferably 0.2 or less, and still more preferably 0.1 or less.
• the mass ratio [polymer b / (polymer b + metal)] is calculated in the same manner as the mass ratio [dispersant B / (dispersant B + metal)].
• the mass ratio of the dispersant B to the total amount of the dispersant B and silver in the silver fine particle dispersion is preferably 0.01 or more, more preferably 0.03 or more, further preferably 0.05 or more, from the viewpoint of miniaturization of silver fine particles.
• the concentration is preferably 0.3 or less, more preferably 0.2 or less, and still more preferably 0.1 or less.
• the mass ratio [dispersant B / (dispersant B + silver)] is measured using a differential thermogravimetric simultaneous measurement device (TG / DTA), similarly to the mass ratio [dispersant B / (dispersant B + metal)]. From the masses of the dispersant B and the metal (silver) measured by the methods described in Examples.
• the cumulant average particle diameter of the fine metal particles a in the fine metal particle dispersion is 2 nm or more from the viewpoint of improving the dispersion stability of the fine metal particles, improving the storage stability of the dispersion, and increasing the concentration of the fine metal particles. Is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, even more preferably 20 nm or more, and from the viewpoint of miniaturization of metal fine particles, is 50 nm or less, preferably 40 nm or less, More preferably, it is 30 nm or less.
• the said cumulant average particle diameter is measured by the method described in an Example.
• the metal concentration of the metal fine particle dispersion is 30% by mass or more, preferably 35% by mass or more, more preferably 40% by mass or more, and further preferably 45% by mass or more, from the viewpoint of facilitating the preparation of the ink described below. And from the viewpoint of improving the dispersion stability of the metal fine particles and improving the storage stability of the dispersion, is 80% by mass or less, preferably 70% by mass or less, more preferably 60% by mass or less, and furthermore Preferably it is 50% by mass or less.
• the metal concentration of the metal fine particle dispersion is calculated by the method described in the examples.
• the metal fine particle dispersion of the present invention is preferably produced by a method of reducing a metal raw material compound A containing a metal constituting the metal fine particles a in an aqueous solvent C in the presence of a dispersant B. It is considered that the dispersant B present in the system is coordinated and adsorbed to the metal ions, and the metal ions are reduced by the reduction reaction, thereby forming metal fine particles a.
• the reduction reaction of the metal raw material compound A is preferably performed using the reducing agent D from the viewpoint of miniaturization and high concentration of the metal fine particles and from the viewpoint of improving the storage stability of the dispersion. Thereby, fine metal fine particles a can be obtained with a high yield.
• the method of mixing the metal raw material compound A, the dispersant B, the aqueous solvent C, and the reducing agent D is not particularly limited.
• a method I (method I) including a step of mixing a mixed solution IA containing a metal raw material compound A, a dispersant B, and an aqueous solvent C with a reducing agent D, contains a dispersing agent B and a reducing agent D.
• a method (method II) including a step of mixing the mixture IIA with the mixture IIB containing the metal raw material compound A and the aqueous solvent C is exemplified.
• method I is preferable from the viewpoint of miniaturization and high concentration of metal fine particles and from the viewpoint of improving the storage stability of the dispersion.
• Method I includes Step 1 of mixing a mixture IA containing a metal raw material compound A, a dispersant B, and an aqueous solvent C with a reducing agent D (hereinafter, also simply referred to as “Step 1”).
• the mixed solution IA can be obtained by mixing the metal raw material compound A, the dispersant B, and the aqueous solvent C by a known method.
• the metal raw material compound A is not particularly limited as long as it is a compound containing the above-mentioned metal, and examples thereof include a metal salt of an inorganic acid or an organic acid, a metal oxide, a metal hydroxide, a metal sulfide, and a metal halide.
• the metal salt include metal salts of inorganic acids such as nitrates, nitrites, sulfates, carbonates, ammonium salts and perchlorates; and metal salts of organic acids such as acetates.
• the metal raw material compound A can be used alone or in combination of two or more.
• At least one selected from a metal salt and a metal oxide of an inorganic acid or an organic acid more preferably a metal salt of an inorganic acid, further preferably a metal salt of nitric acid, still more preferably It is silver nitrate.
• the aqueous solvent C is preferably one containing water as a main component, and may further contain an organic solvent.
• the organic solvent include aliphatic alcohols having 1 to 4 carbon atoms such as ethanol and 2-propanol, ketones having 3 to 8 carbon atoms such as acetone, and ethers such as tetrahydrofuran.
• the content of water in the aqueous solvent C is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and still more preferably 95% by mass or more from the viewpoint of environmental friendliness. .
• the content of the metal raw material compound A in the mixed solution IA is preferably 20% by mass or more, more preferably 30% by mass or more, still more preferably 35% by mass or more, and still more preferably 40% by mass, from the viewpoint of increasing the concentration. %, More preferably 45% by mass or more, and from the viewpoint of miniaturization of metal fine particles and improvement in storage stability of the dispersion, preferably 90% by mass or less, more preferably 80% by mass or less. It is preferably at most 70% by mass, more preferably at most 60% by mass, even more preferably at most 55% by mass.
• the content of the dispersant B in the mixed solution IA is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, from the viewpoint of miniaturization of the metal fine particles, and From the viewpoint of improving the dispersion stability of metal fine particles and improving storage stability, and from the viewpoint of increasing the concentration of metal fine particles, preferably 10% by mass or less, more preferably 7% by mass or less, and still more preferably 5% by mass. %, More preferably 4% by mass or less.
• the content of the aqueous solvent C in the mixed solution IA is preferably 5% by mass or more, more preferably 20% by mass, from the viewpoints of miniaturization and high concentration of metal fine particles, and from the viewpoint of improving the storage stability of the dispersion. %, More preferably 30% by mass or more, even more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less, and still more preferably 50% by mass or less.
• the reducing agent D is not particularly limited, and any of an inorganic reducing agent and an organic reducing agent can be used.
• the organic reducing agent include ethanolamine, N-methylethanolamine, N, N-dimethylethanolamine (2- (dimethylamino) ethanol), N, N-diethylethanolamine, diethanolamine, N-methyldiethanolamine, and triethanolamine.
• alkylamines ethylenediamine, triethylenediamine, tetramethylethylenediamine, diethylenetriamine, dipropylenetriamine
• Aliphatic amines such as (poly) alkylenepolyamines such as ethylenetetramine and tetraethylenepentamine; alicyclic amines such as piperidine, pyrrolidine, N-methylpyrrolidine, morpholine; aniline, N-methylaniline, toluidine, anisidine, phenetidine and the like
• Aromatic amines amines such as aralkylamines such
• the inorganic reducing agent examples include borohydride salts such as sodium borohydride and ammonium borohydride; aluminum hydride salts such as lithium aluminum hydride and potassium aluminum hydride; hydrazines such as hydrazine and hydrazine carbonate; hydrogen gas; Is mentioned.
• the reducing agent D may be used alone or in combination of two or more.
• the reducing agent D is preferably an organic reducing agent, more preferably an amine, further preferably an amine, from the viewpoint of miniaturization and high concentration of the metal fine particles, and from the viewpoint of improving the storage stability of the dispersion. It is an alkanolamine having a number of from 2 to 6, more preferably a tertiary alkanolamine having from 2 to 6 carbon atoms, and still more preferably N, N-dimethylethanolamine.
• the method of mixing the mixture IA and the reducing agent D is not particularly limited, but from the viewpoint of controlling the reduction reaction, a method of adding the reducing agent D to the mixture IA is preferable, and the reducing agent D is added dropwise to the mixture IA.
• the method is more preferred.
• the dropping speed of the reducing agent D can be appropriately set according to the scale of production.
• the temperature of the reduction reaction is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, even more preferably 30 ° C. or higher, and preferably 70 ° C. or lower, more preferably 60 ° C. or lower, and further preferably 50 ° C. or lower. It is preferable to carry out the reduction reaction within the range described above.
• the reduction reaction may be performed under an air atmosphere or under an inert gas atmosphere such as nitrogen gas.
• the amount of each component charged when producing the metal fine particle dispersion is as follows from the viewpoints of miniaturization, high concentration and productivity of the metal fine particles, and improvement of the storage stability of the dispersion.
• the charged amount of the metal raw material compound A based on the total charged amount of the metal raw material compound A, the dispersant B, the aqueous solvent C, and the reducing agent D is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass. % Or more, and preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass or less.
• the amount of the dispersant B added to the total amount of the metal raw material compound A, the dispersant B, the aqueous solvent C, and the reducing agent D is preferably 0.5% by mass or more, more preferably 1% by mass or more, and still more preferably 1% by mass or more. It is at least 0.5% by mass, and preferably at most 7% by mass, more preferably at most 5% by mass, even more preferably at most 3% by mass.
• the amount of the aqueous solvent C based on the total amount of the metal raw material compound A, the dispersant B, the aqueous solvent C, and the reducing agent D is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass.
• the charged amount of the reducing agent D based on the total charged amount of the metal raw material compound A, the dispersant B, the aqueous solvent C, and the reducing agent D is preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass. And preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less.
• the charged molar ratio of the reducing agent D and the metal raw material compound A [reducing agent D / metal raw material compound A] is preferably 0.5 or more, more preferably 1 or more, still more preferably 1.5 or more, and still more preferably It is 2 or more, more preferably 2.5 or more, and preferably 10 or less, more preferably 7 or less, still more preferably 5 or less, and still more preferably 4 or less.
• the metal fine particle dispersion of the present invention may contain glycerin, triethylene glycol, or the like as a humectant in an amount of 1% by mass or more and 10% by mass or less as a humectant, depending on the application, An agent may be contained.
• the additive may be blended at the time of the reduction reaction, or may be blended after obtaining the metal fine particle dispersion.
• Step 2 In the production method of the present invention, from the viewpoint of removing impurities, improving the dispersion stability of the metal fine particles, and improving the storage stability of the dispersion, a step 2 (purifying the metal fine particle dispersion obtained in the step 1) Hereinafter, it is also preferable to simply include “step 2”).
• the dispersion after the reduction reaction of the metal raw material compound A contains impurities such as an unreacted reducing agent, a counter ion of a metal ion, and an excessive dispersing agent B that does not contribute to the dispersion of the metal fine particles. Therefore, these impurities can be removed through Step 2.
• the method for purifying the metal fine particle dispersion is not particularly limited, and examples thereof include membrane treatment such as dialysis and ultrafiltration; and centrifugal separation. Above all, from the viewpoint of efficiently removing impurities, membrane treatment is preferable, and dialysis is more preferable. As the material of the dialysis membrane used for dialysis, regenerated cellulose is preferable.
• the molecular weight cut off of the dialysis membrane is preferably 1,000 or more, more preferably 5,000 or more, still more preferably 10,000 or more, and preferably 100,000 or less, from the viewpoint of efficiently removing impurities. , More preferably 70,000 or less.
• the metal fine particle dispersion obtained in the step 1 is put into a cylindrical dialysis tube, and after sealing both ends of the dialysis tube, the tube is filled with a large amount of ion-exchanged water using the tube as a buffer. It can be carried out by placing it in a container and leaving it for a predetermined time. This makes it possible to remove impurity ions having a formula weight of not more than the cut-off molecular weight and dispersants having a molecular weight of not more than the cut-off molecular weight from the metal fine particle dispersion.
• the temperature of the dialysis treatment is preferably 10 ° C. or higher, more preferably 15 ° C. or higher, further preferably 20 ° C. or higher, and preferably 60 ° C. or lower, more preferably 50 ° C. or lower, from the viewpoint of processing efficiency. Preferably it is 40 ° C. or lower.
• the production method of the present invention preferably further includes a step 3 of concentrating the fine metal particle dispersion obtained in the step 1 or 2.
• the method for concentrating the metal fine particle dispersion is not particularly limited as long as the aqueous medium contained in the metal fine particle dispersion can be removed. Among them, a method of distilling the aqueous medium under heating or reduced pressure is preferable.
• the heating temperature is preferably 35 ° C. or higher, more preferably 45 ° C. or higher, and still more preferably 55 ° C.
• the concentration of the metal fine particle dispersion is preferably performed while controlling the solid content concentration of the dispersion to be in a desired range.
• the aqueous solvent C contains an organic solvent, it is preferable to remove the organic solvent together with water in the step 3.
• the organic solvent in the metal fine particle dispersion obtained in Step 3 is preferably substantially removed, but may remain as long as the effects of the present invention are not impaired.
• the amount of the residual organic solvent is preferably 0.1% by mass or less, more preferably 0.01% by mass or less.
• the metal fine particle dispersion of the present invention contains finely dispersed metal fine particles at a high concentration and has excellent storage stability, so that it can be used for a wide range of applications.
• various inks wiring materials, electrode materials, conductive materials such as MLCCs (multilayer ceramic capacitors); bonding materials such as solder; various sensors; automatic recognition technology using short-range wireless communication (RFID (radio frequency identifier)) Antennas such as tags; catalysts; optical materials; medical materials and the like.
• RFID radio frequency identifier
• the metal fine particle dispersion of the present invention is preferably contained in an aqueous ink (hereinafter, also referred to as “aqueous ink” or “ink”) and used as an ink for metallic printing. Since the dispersion of the metal fine particles is excellent in the dispersion stability of the metal fine particles a, the storage stability of the aqueous ink can be improved.
• the aqueous ink preferably further contains an organic solvent from the viewpoint of storage stability and from the viewpoint of ejection stability when an inkjet printing method is used as a printing method described later.
• the organic solvent preferably contains at least one organic solvent having a boiling point of 90 ° C. or higher.
• the weighted average boiling point of the organic solvent is preferably 150 ° C. or higher, more preferably 180 ° C. or higher, and preferably 240 ° C. or lower, more preferably 220 ° C. or lower, and further preferably 200 ° C. or lower.
• organic solvent examples include polyhydric alcohols, polyhydric alcohol alkyl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
• polyhydric alcohols and polyhydric alcohol alkyl ethers are preferable, and ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, trimethylolpropane, diethylene glycol diethyl ether and diethylene glycol monoisobutyl ether are preferred.
• One or more selected from the group is more preferable, and one or more selected from propylene glycol and diethylene glycol monoisobutyl ether is further preferable.
• the water-based ink may further include a fixing aid such as a dispersion of polymer particles, a humectant, a wetting agent, a penetrant, a surfactant, a viscosity modifier, a defoaming agent, and a preservative, which are generally used in the water-based ink, if necessary.
• a fixing aid such as a dispersion of polymer particles, a humectant, a wetting agent, a penetrant, a surfactant, a viscosity modifier, a defoaming agent, and a preservative, which are generally used in the water-based ink, if necessary.
• Various additives such as an agent, a fungicide, and a rust inhibitor can be added, and a filtration treatment with a filter or the like can be further performed.
• the content of each component of the aqueous ink and the physical properties of the ink are as follows.
• the content of the metal in the aqueous ink is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more from the viewpoint of print density. From the viewpoint of lowering and improving storage stability, preferably 20% by mass or less, more preferably 17% by mass or less, further preferably 15% by mass or less, still more preferably 13% by mass or less, and still more preferably 11% by mass or less. It is as follows.
• the content of the metal in the aqueous ink can be measured by the method described in Examples.
• the total content of the metal and the dispersant B in the aqueous ink is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass or more, from the viewpoint of fixability. From the viewpoint of reducing the viscosity of the ink at the time of volatilization and improving the storage stability, it is preferably 22% by mass or less, more preferably 20% by mass or less, still more preferably 17% by mass or less, and still more preferably 15% by mass or less. It is even more preferably at most 13% by mass.
• the total content of the metal and the dispersant B in the aqueous ink is calculated from the content of the metal in the aqueous ink and the mass ratio [dispersant B / (dispersant B + metal)] calculated by the method described in Examples. Can be calculated.
• the content of the organic solvent in the water-based ink is preferably 10 mass from the viewpoints of storage stability of the water-based ink, ejection stability when an inkjet printing method is used as a printing method described later, and fixability and print density. %, More preferably at least 20% by mass, even more preferably at least 30% by mass, and preferably at most 50% by mass, more preferably at most 45% by mass, even more preferably at most 40% by mass.
• the content of water in the aqueous ink is preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass or more, from the viewpoints of storage stability of the aqueous ink, fixability and print density. And preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less.
• the mass ratio of the metal in the total solid content in the aqueous ink [metal / (total solid content of the aqueous ink)] is preferably 0.3 or more from the viewpoints of storage stability of the aqueous ink, fixability and print density. It is more preferably at least 0.5, still more preferably at least 0.7, even more preferably at least 0.8, and preferably at most 0.98, more preferably at most 0.96, even more preferably at least 0.94. It is as follows.
• the average particle size of the cumulant of the metal fine particles a in the aqueous ink is preferably the same as the average particle size in the metal fine particle dispersion, and the preferable mode of the average particle size is also the average particle size in the metal fine particle dispersion.
• the diameter is the same as the preferred embodiment.
• the viscosity of the aqueous ink at 32 ° C. is preferably 2 mPa ⁇ s or more, more preferably 3 mPa ⁇ s or more, still more preferably 5 mPa ⁇ s or more, and preferably 12 mPa ⁇ s from the viewpoint of improving storage stability.
• the viscosity of the water-based ink can be measured using an E-type viscometer.
• the pH at 20 ° C. of the water-based ink is preferably 7.0 or more, more preferably 7.2 or more, and still more preferably 7.5 or more, from the viewpoint of storage stability. Further, from the viewpoints of member resistance and skin irritation, the pH is preferably 11 or less, more preferably 10 or less, and further preferably 9.5 or less.
• the pH of the aqueous ink can be measured by a conventional method.
• a water-based ink is applied on a print medium to obtain a metallic print having a metal film formed thereon. Since the water-based ink can obtain a printed matter having excellent metallic luster, it can be suitably used for metallic printing, particularly as a flexographic printing ink, a screen printing ink, a gravure printing ink, or an inkjet recording ink. . Particularly, from the viewpoint of excellent ejection stability, it is more preferable to use it as an ink for inkjet recording.
• the water-based ink When the water-based ink is used as an ink for ink-jet recording, the water-based ink can be loaded into a known ink-jet recording apparatus and ejected as ink droplets onto a print medium to form an image or the like.
• the inkjet recording apparatus there are a thermal type and a piezo type.
• the aqueous ink containing the metal fine particle dispersion of the present invention is more preferably used as a piezo type aqueous ink for inkjet recording. That is, as a method of applying the ink on a print medium, an inkjet printing method is preferable.
• Examples of the printing medium of the metallic printing method for printing using the water-based ink include plain paper having high water absorption, coated paper having low water absorption, and a non-water-absorbing resin film.
• Examples of the coated paper include general-purpose glossy paper and multicolor foam gloss paper.
• a resin film is preferable from the viewpoint of obtaining a printed matter having excellent metallic luster.
• the resin film is preferably at least one selected from a polyester film such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), a polyvinyl chloride film, a polypropylene film, and a polyethylene film.
• the resin film may use a corona-treated base material.
• Examples of generally available resin films include Lumirror T60 (manufactured by Toray Industries, Inc., polyester), Teonex Q51-A4 (manufactured by Teijin Film Solutions Limited, polyethylene naphthalate), PVC80BP (manufactured by Lintec Corporation, vinyl chloride) ), DGS-210WH (Roland DG Corporation, vinyl chloride), transparent vinyl chloride RE-137 (Mimaki Engineering Co., Ltd., vinyl chloride), Kinas KEE70CA (Lintech Corporation, polyethylene), YUPO SG90 PAT1 (Lintech Corporation) FOR, FOA (all manufactured by Futamura Chemical Co., Ltd., polypropylene), Boneal RX (produced by Kojin Film & Chemicals, nylon), Emblem ONBC (Unitika Ltd.) , Nylon), and the like.
• Lumirror T60 manufactured by Toray Industries, Inc., polyester
• Teonex Q51-A4 manufactured by Teijin Film Solutions Limited, poly
• the head temperature of the inkjet head is preferably 15 ° C. or higher, more preferably 20 ° C. or higher, even more preferably 25 ° C. or higher, and preferably 45 ° C. or lower, more preferably 40 ° C., from the viewpoint of improving the metallic gloss.
• the temperature is more preferably 35 ° C or less.
• the head voltage of the inkjet head is preferably 5 V or more, more preferably 10 V or more, further preferably 15 V or more, and preferably 40 V or less, more preferably 35 V or less, from the viewpoint of printing efficiency and the like. Is 30V or less.
• the driving frequency of the head is preferably 1 kHz or more, more preferably 5 kHz or more, further preferably 10 kHz or more, and preferably 50 kHz or less, more preferably 40 kHz or less, further preferably from the viewpoint of printing efficiency or the like. It is 35 kHz or less.
• the amount of ink droplets discharged is preferably 5 pL or more, more preferably 10 pL or more, and preferably 30 pL or less, more preferably 20 pL or less.
• the application amount of the ink to the print medium, as a solid content preferably 0.5 g / m 2 or more, more preferably 1 g / m 2 or more, more preferably 2 g / m 2 or more, and preferably 20 g / m 2 or less, more preferably 15 g / m 2 or less, and still more preferably 10 g / m 2 or less.
• the resolution is preferably 200 dpi or more, more preferably 300 dpi or more, and preferably 1,000 dpi or less, more preferably 800 dpi or less, and still more preferably 600 dpi or less.
• “resolution” in this specification refers to the number of dots per inch (2.54 cm) formed on a print medium.
• “600 dpi resolution” corresponds to a case where ink droplets are ejected onto a print medium using a line head in which the number of nozzle holes per nozzle row length is arranged at 600 dpi (dots / inch).
• a row of dots at 600 dpi per inch is formed in a direction perpendicular to the transport direction of the print medium, and when the ink droplets are ejected while moving the print medium in the transport direction, the print medium is also printed in the transport direction. This means that a row of dots of 600 dpi is formed per inch.
• the resolution in the direction perpendicular to the transport direction of the print medium and the resolution in the transport direction are expressed as the same value.
• Heat treatment In the present invention, from the viewpoint of improving the metallic luster, it is preferable to heat-treat the ink film on the print medium after applying the ink on the print medium.
• the medium in the ink film is evaporated and dried to form a metal film exhibiting metallic luster.
• the method of the heat treatment is not particularly limited, a method of heating by applying hot air to the ink film surface on the print medium, a method of heating by bringing a heater close to the ink film surface on the print medium, and a method of heating the ink film on the print medium.
• the heat treatment temperature is preferably lower than the temperature at which the print medium is deformed.
• the heat treatment is carried out under normal pressure, preferably at least 40 ° C, more preferably at least 50 ° C, still more preferably at least 55 ° C, and preferably at most 90 ° C, more preferably at most 80 ° C, from the viewpoint of improving the metallic luster.
• the heat treatment time in this case is preferably 1 minute or more, and is preferably 30 minutes or less, more preferably 20 minutes or less, further preferably 10 minutes or less, and even more preferably 5 minutes or less.
• Monodisperse polystyrene kit of known molecular weight [PStQuick B (F-550, F-80, F-10, F-1, A-1000), PStQuick C (F-288, F-40, F-4, A-5000) , A-500), east It was measured using a chromatography Co., Ltd.].
• PStQuick B F-550, F-80, F-10, F-1, A-1000
• PStQuick C F-288, F-40, F-4, A-5000
• A-500 east It was measured using a chromatography Co., Ltd.
• 0.1 g of the polymer was mixed with 10 mL of the above eluent in a glass vial, and the mixture was stirred with a magnetic stirrer at 25 ° C. for 10 hours, and a syringe filter (DISMIC-13HP PTFE 0.2 ⁇ m, manufactured by Advantech Co., Ltd.) Used after filtration.
• thermogravimetric differential thermal analyzer (TG / DTA) (manufactured by Hitachi High-Tech Science Co., Ltd., trade name: STA7200RV)
• 10 mg of the sample was weighed into an aluminum pancel, and the dried metal powder was measured at 10 ° C./min.
• the temperature was raised from 35 ° C. to 550 ° C. at a heating rate of, and the mass loss was measured under an air flow of 50 mL / min.
• the mass ratio [dispersant B / (dispersant B + metal)] was calculated with the mass loss from 35 ° C. to 550 ° C. being the mass of the dispersant B and the remaining mass at 550 ° C. being the mass of the metal.
• Step 3 The silver fine particle dispersion (d2-1) obtained above was concentrated under reduced pressure at 60 ° C. so that the solid content concentration became 50%, to obtain a silver fine particle dispersion (D1).
• the mass ratio [dispersant B / (dispersant B + metal)] and metal concentration of the silver fine particle dispersion (D1) were measured and calculated by the methods (5) and (6), and the average cumulant particles immediately after the dispersion was produced.
• the diameter X (hereinafter also referred to as “cumulant average particle diameter X”) was measured by the method (3). Table 2 shows the results.
• Examples 1-2, 1-3 Silver fine particle dispersions (D2) and (D3) were obtained in the same manner as in Example 1-1, except that the charged amount of water in step 1 was changed as shown in Table 1.
• Examples 1-4, 1-5 Silver fine particle dispersions (D4) and (D5) were obtained in the same manner as in Example 1-1, except that the charged amount of DMAE in step 1 was changed as shown in Table 1.
• Example 1-6 A silver fine particle dispersion (D6) was obtained in the same manner as in Example 1-1, except that step 1 of Example 1-1 was changed as follows. (Step 1 ') In a 100 mL glass beaker, 0.8 g of BYK-2015dry as dispersant B and 22.6 g of DMAE as reducing agent D were added, and the mixture was stirred at room temperature using a magnetic stirrer until it became visually transparent, and mixed. A liquid (IIA-6) was obtained.
• a mixed solution (IIB-6) in which 14.4 g of silver nitrate as the metal raw material compound A and 13.2 g of ion-exchanged water as the aqueous solvent C were dissolved in a 100 mL dropping funnel until silver nitrate crystals were no longer visible,
• the mixed solution (IIB-6) was added dropwise to the mixed solution (IIA-6) whose temperature was controlled with a water bath at 40 ° C. over 30 minutes. Thereafter, the mixture was stirred for 5 hours while controlling the temperature of the reaction solution in a water bath at 40 ° C., and then air-cooled to obtain a dark brown liquid containing silver fine particles a6.
• the resulting dark brown liquid was allowed to stand for 1 hour to remove the precipitate, and then the supernatant was obtained as a fine silver particle dispersion (d1-6), and the same steps as steps 2 and 3 of Example 1-1 were performed. Advanced to.
• Examples 1-7, 1-8 Silver fine particle dispersions (D7) and (D8) were obtained in the same manner as in Example 1-1, except that the charged amount of silver nitrate in step 1 was changed as shown in Table 1.
• Example 1-9 Silver fine particle dispersion (D9) was obtained in the same manner as in Example 1-1, except that DMAE was changed to sodium borohydride (hereinafter, also referred to as “NaBH 4 ”) as reducing agent D.
• NaBH 4 sodium borohydride
• Comparative Example 1-1 A silver fine particle dispersion (DC1) was obtained in the same manner as in Example 1-1, except that cholic acid was used instead of BYK-2015dry.
• Comparative Example 1-2 A silver fine particle dispersion was prepared in the same manner as in Example 1-1, except that John Krill 69 (trade name, manufactured by BASF, styrene / acrylic acid polymer) (hereinafter referred to as “JC69”) was used instead of BYK-2015dry. (DC2) was obtained.
• JC69 John Krill 69 (trade name, manufactured by BASF, styrene / acrylic acid polymer) (hereinafter referred to as “JC69”) was used instead of BYK-2015dry. (DC2) was obtained.
• Comparative Example 1-3 Dispersion of fine silver particles was performed in the same manner as in Example 1-1 except that MA7323 (trade name, manufactured by Kao Corporation, acrylic acid / polyethylene glycol methacrylate polymer) (hereinafter, referred to as “MA7323”) was used instead of BYK-2015dry. A body (DC3) was obtained.
• MA7323 trade name, manufactured by Kao Corporation, acrylic acid / polyethylene glycol methacrylate polymer
• Comparative Example 1-4 A silver fine particle dispersion (DC4) was obtained in the same manner as in Example 1-1 except that a mixture of 0.64 g of BYK-2015dry and 0.16 g of cholic acid was used instead of 0.8 g of BYK-2015dry.
• each notation in Table 1 is as follows.
• * 1 Content (% by mass) of polymer b in dispersant B.
• * 2 The charged amount (% by mass) of each component with respect to the total charged amount of metal raw material compound A, dispersant B, aqueous solvent C, and reducing agent D.
• * 3 Method I is a method of mixing a mixture IA containing a metal raw material compound A, a dispersant B, and an aqueous solvent C with a reducing agent D
• Method II is a mixture IIA of a dispersant B and a reducing agent D and a metal raw material. This is a method of mixing the compound A and the mixed solution IIB of the aqueous solvent C.
• * 4 A mixture of BYK-2015dry 80% by mass and cholic acid 20% by mass.
• the metal fine particle dispersions of the examples have a higher yield and a smaller cumulant average particle diameter of the metal fine particles a than those of the comparative example. Further, the metal fine particle dispersions of the examples are excellent in storage stability as compared with those of the comparative examples, and are excellent in the dispersion stability of the metal fine particles even if the metal fine particles are contained at a high concentration. I understand that.
• Comparative Example 1 dispersion was carried out using cholic acid as a low molecular weight dispersant, and in Comparative Examples 2 and 3, polymer b containing all the structural units derived from monomers (b-1) to (b-3) was dispersed.
• Example 2-1 With the total amount of the ink being 30 g, the metal fine particle dispersion (D1) obtained in Example 1-1 was blended so that the metal content was 10%, and the propylene glycol content was 35%, and diethylene glycol monoisobutyl was further added.
• ether 1%, content of polyether-modified silicone surfactant (trade name: KF-6011, manufactured by Shin-Etsu Chemical Co., Ltd., PEG-11 methyl ether dimethicone) 0.5%, acetylene glycol-based 0.5% content of surfactant (trade name: Surfynol 104 (2,4,7,9-tetramethyl-5-decyne-4,7-diol), manufactured by Evonik Industries, effective component 100%) , And the rest were mixed to make ion-exchanged water to prepare Ink 1. In addition, preparation was performed by putting each component into a 50 mL glass vial while stirring with a magnetic stirrer.
• Example 2-2 to 2-9 and Comparative Examples 2-1 to 2-4 The metal fine particle dispersion (D1) in Example 2-1 was replaced with the metal fine particle dispersions (D2) to (D9) obtained in Examples 1-2 to 1-9 and Comparative Examples 1-1 to 1-4. Except for changing to (DC1) to (DC4), the same operation as in Example 2-1 was performed to obtain inks 2 to 9 and C1 to C4.
• Ink jet print evaluation device equipped with an ink jet head (trade name: KJ4B-QA06NTB-STDV, piezo type, 2,656 nozzles, manufactured by Kyocera Corporation) in an environment of a temperature of 25 ⁇ 1 ° C. and a relative humidity of 30 ⁇ 5%. (Manufactured by Tri-Tech Co., Ltd.) were filled with the respective inks obtained in Examples and Comparative Examples.
• KJ4B-QA06NTB-STDV piezo type, 2,656 nozzles, manufactured by Kyocera Corporation
• a head voltage of 26 V, a frequency of 20 kHz, an appropriate amount of ejected liquid of 18 pl, a head temperature of 32 ° C., a resolution of 600 dpi, a flushing frequency of 200 before ejection, and a negative pressure of ⁇ 4.0 kPa are set so that the longitudinal direction of the print medium is the same as the transport direction. Then, the print medium was fixed on the carriage under reduced pressure. The print command is transferred to the print evaluation device, and the ink is ejected and adhered to the print medium at a duty of 100%. Then, the ink on the print medium is heated and dried at 60 ° C. for 2 minutes on a hot plate, and the metallic material is dried. Printed matter was obtained.
• a polyester film (trade name: Lumirror T60, thickness 75 ⁇ m, water absorption 2.3 g / m 2 , manufactured by Toray Industries, Inc.) was used as a print medium.
• the water absorption was measured using an automatic scanning absorptiometer (eg, KM500win, manufactured by Kumagai Riki Kogyo Co., Ltd.) at 23 ° C. and a relative humidity of 50% under a condition of pure water contact time of 100 ms. It was measured as a quantity.
• ⁇ Evaluation of discharge stability> After leaving the nozzle for 30 minutes without protecting the nozzle surface after printing with the inkjet printing evaluation device, a print check pattern that can be used to determine the presence or absence of ejection from all nozzles is printed on a print medium, and the nozzle is missing (normal ejection). The number of nozzles (not used) was counted, and the ejection stability was evaluated. The smaller the number of missing nozzles, the better the ejection stability.
• the inks of the examples are more excellent in ejection stability than the inks of the comparative examples.
• the metal fine particle dispersion of the present invention contains finely dispersed metal fine particles at a high concentration and has excellent storage stability, and thus can be suitably used for metallic printing in various fields.

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