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
  • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M1/00—Inking and printing with a printer's forme
  • B41M1/10—Intaglio printing ; Gravure printing
• • 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
  • C09D11/02—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
  • C09D11/108—Hydrocarbon resins

Definitions

• the present invention relates to a water-based ink for plate printing and a plate printing method using the water-based ink.
• Gravure printing, flexographic printing, letterpress printing, etc. using printing plates such as concave plates, flat plates, and letterpress plates are widely performed because the printing quality can be controlled by changing the mode of the plate and high-definition printing can be performed.
• oil-based inks are often used for plate printing such as gravure printing, but there are problems in terms of working environment, global environment, disaster prevention, and residual solvent when used in food-related fields.
• the amount of oil-based ink used in gravure printing is large, there is a problem that it is difficult to meet the market needs for a wide variety of products and small lots. Therefore, plate printing using water-based ink is drawing attention.
• Patent Document 1 describes as a water-based polyurethane resin that is excellent in wettability, adhesiveness, and laminating performance to a plastic film and is useful for inks, paints, adhesives, and particularly in the field of water-based printing inks.
• an aqueous polyurethane resin in which an epoxy compound is added and reacted as a chain extender after obtaining an aqueous dispersion / water-soluble body of the polyurethane resin.
• Patent Document 2 contains pigments, polymers, water-soluble organic solvents, surfactants, and water as water-based gravure inks that have a low environmental load and can be printed with high definition due to excellent leveling properties. Disclosed are water-based gravure inks in which the total amount of the water-soluble organic solvent is 15% by mass or less, the content of glycol ether is 1 to 10% by mass, and the content of water is 50 to 70% by mass. And in Patent Document 2, an uncrosslinked polymer is used as a polymer.
• the present invention relates to the following (A) to (C) and water-based ink for plate printing containing water.
• the present invention relates to a water-based ink for plate printing, which is less likely to cause tone jumps and has excellent blocking resistance even with a low liquid absorption printing medium.
• the present inventors use crosslinked polymer particles containing no pigment as a fixing agent, and contain pigments, crosslinked polymer particles containing no pigment, and a water-soluble organic solvent having a specific boiling point in specific amounts. It was found that the above-mentioned problems can be solved by making the particles. That is, the present invention relates to the following [1] and [2].
• C Water-soluble organic solvent having a boiling point of 100 ° C. or more and 260 ° C. or less: 1% by mass % Or more and 15% by mass or less
• the present invention it is possible to provide a water-based ink for plate printing, which is less likely to cause tone jump and has excellent blocking resistance, and a plate printing method using the water-based ink, even for a low liquid absorption printing medium. ..
• the water-based ink for plate printing of the present invention contains the following (A) to (C) and water.
• the above-mentioned content in the ink of the present invention means a composition in an ink tank equipped in a printing machine used for printing. That is, the ink of the present invention may be adjusted so as to have the composition of the ink of the present invention by keeping the liquid component concentrated during transportation or storage and diluting it with a liquid component such as water during printing.
• water-based means that water accounts for the largest proportion of the ink medium.
• Low liquid absorption is a concept including low liquid absorption and non-liquid absorption of water-based ink. Low liquid absorption can be evaluated by the water absorption of pure water.
• the amount of water absorption per surface area of the print medium at a contact time of 100 msec between the print medium and pure water is 0 g / m 2 or more and 10 g / m 2 or less.
• the amount of water absorption can be measured using an automatic scanning liquid absorption meter.
• Print is a concept including printing and printing for recording characters and images.
• the water-based ink for plate printing of the present invention is less likely to cause tone jump even with a low liquid absorption printing medium, and has excellent blocking resistance.
• the reason is not clear, but it can be considered as follows.
• the ink of the present invention contains 1% by mass or more and 15% by mass or less of a water-soluble organic solvent having a boiling point of 100 ° C. or higher and 260 ° C. or lower. It is considered that blocking can be suppressed because the drying property of the ink on the surface of the printing medium can be optimized by using a water-soluble organic solvent having a boiling point of 260 ° C. or lower. Further, by using a water-soluble organic solvent having a boiling point of 100 ° C.
• the pigment used in the ink of the present invention is preferably one that can maintain a dispersed state in a water-based ink with a particle size of 250 nm or less.
• Suitable forms of this pigment include (i) a pigment that can remain dispersed without a dispersant, i.e. a self-dispersing pigment, and (ii) a pigment dispersed with a low molecular weight or high molecular weight surfactant. Examples thereof include the form of the pigment particles and (iii) the form of the polymer particles containing the pigment. Among these, the form of the polymer particles containing the pigment is preferable from the viewpoint of suppressing the tone jump of the obtained printed matter and improving the blocking resistance.
• the polymer particles containing a pigment are particles in the form in which the polymer contains the pigment, particles in the form in which a part of the pigment is exposed on the surface of the particles composed of the polymer and the pigment, and the polymer is the pigment. It means particles in the form of being partially adsorbed, and may be a mixture thereof. Of these, particles in the form of a polymer containing a pigment are more preferable.
• the pigment used in the present invention may be either an inorganic pigment or an organic pigment, but an organic pigment is more preferable.
• the inorganic pigment include carbon black and metal oxide, and carbon black is preferable for black ink.
• carbon black include furnace black, thermal lamp black, acetylene black, and channel black.
• the white ink include metal oxides such as titanium dioxide, zinc oxide, silica, alumina and magnesium oxide.
• These inorganic pigments may be surface-treated with a known hydrophobizing agent such as a titanium coupling agent, a silane coupling agent, or a higher fatty acid metal salt.
• organic pigment examples include azo pigments, diazo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, quinophthalone pigments and the like.
• the hue is not particularly limited, and any chromatic pigment such as yellow, magenta, cyan, red, blue, orange, and green can be used in the chromatic ink.
• the pigment can be used alone or in combination of two or more.
• the polymer constituting the polymer particles containing the pigment (hereinafter, also referred to as “polymer a”) is not particularly limited as long as it has at least a pigment-dispersing ability.
• the pigment-containing polymer particles (hereinafter, also referred to as “pigment-containing polymer particles”) are pigment-containing crosslinked polymer particles (hereinafter, “pigment-containing crosslinks”) formed by further cross-linking the pigment-containing polymer particles with a cross-linking agent. It is more preferably "polymer particles").
• the polymer a before cross-linking may be a water-soluble polymer or a water-insoluble polymer, but a water-insoluble polymer is more preferable.
• the polymer used is a water-soluble polymer
• the polymer becomes a water-insoluble polymer when crosslinked.
• water-insoluble means that when a polymer that has been dried at 105 ° C. for 2 hours and has reached a constant weight is dissolved in 100 g of water at 25 ° C., the dissolved amount is less than 10 g. This means that the dissolved amount of the polymer is preferably 5 g or less, more preferably 1 g or less.
• the dissolved amount is the dissolved amount when the anionic group of the polymer is 100% neutralized with sodium hydroxide.
• the polymer a is a polymer having a pigment-dispersing ability to disperse a pigment in an aqueous medium containing water as a main component.
• the polymer a can have any structure, but from the viewpoint of improving the storage stability of the ink of the present invention, a vinyl-based polymer obtained by addition polymerization of a vinyl monomer such as a vinyl compound, a vinylidene compound, or a vinylene compound can be used. preferable.
• the vinyl-based polymer preferably contains a structural unit derived from (a-1) ionic monomer (hereinafter, also referred to as "(a-1) component”), and contains (a-1) component and (a-).
• a vinyl-based polymer obtained by copolymerizing a monomer mixture A (hereinafter, also referred to as “monomer mixture A”) containing a hydrophobic monomer (hereinafter, also referred to as “(a-2) component”) is more preferable.
• the vinyl polymer has a structural unit derived from the component (a-1) and a structural unit derived from the component (a-2).
• the (a-1) ionic monomer is preferably used as a monomer component of the polymer a from the viewpoint of improving the dispersion stability of the pigment in the ink of the present invention.
• Examples of the (a-1) ionic monomer include an anionic monomer and a cationic monomer, and an anionic monomer is preferable.
• Examples of the anionic monomer include a carboxylic acid monomer, a sulfonic acid monomer, and a phosphoric acid monomer.
• carboxylic acid monomer examples include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethylsuccinic acid.
• carboxylic acid monomer is more preferable, and one or more selected from acrylic acid and methacrylic acid is further preferable.
• the hydrophobic monomer (a-2) is preferably used as a monomer component in addition to the component (a-1) from the viewpoint of improving the dispersion stability of the pigment in the ink of the present invention.
• the polymer a has a structural unit derived from the component (a-1) and a structural unit derived from the component (a-2).
• Specific examples of the component (a-2) include those described in paragraphs [0020] to [0022] of JP-A-2018-83938.
• alkyl (meth) acrylates having an alkyl group having 1 or more and 22 or less carbon atoms styrene, ⁇ -methylstyrene, and benzyl (meth) acrylate is preferable.
• the (a-3) nonionic monomer (hereinafter, also referred to as “component (a-3)”) can be used from the viewpoint of further improving the dispersion stability of the pigment in the ink of the present invention.
• the component (a-3) is a monomer having a high affinity for water or a water-soluble organic solvent, and is, for example, a monomer containing a hydroxyl group or a polyalkylene glycol chain. Specific examples of the component (a-3) include those described in paragraph [0018] of JP-A-2018-83938.
• the monomer components contained in each component can be used alone or in combination of two or more.
• the content of the structural unit derived from the component (a-3) is as follows from the viewpoint of improving the dispersion stability of the pigment.
• the content of the component (a-1) is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass. % Or less, more preferably 20% by mass or less.
• the content of the component (a-2) is preferably 30% by mass or more, more preferably 40% by mass or more, further preferably 50% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass. % Or less, more preferably 75% by mass or less.
• the content thereof is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less. is there.
• the mass ratio of the component (a-1) to the component (a-2) [(a-1) / (a-2)] is preferably 0.1 or more, more preferably 0.2 or more, still more preferably 0. It is .25 or more, and preferably 1.2 or less, more preferably 1.0 or less, still more preferably 0.8 or less.
• the content of the structural unit derived from the components (a-1) to (a-3) in the polymer a can be determined by measurement, and (a-1) to (a) at the time of producing the polymer a. -3) It is also possible to substitute the charging ratio of the raw material monomer containing the component.
• the content of the component (a-1) is preferably determined by the potentiometric titration method, and the content of the component (a-2) and the component (a-3) is preferably determined by the charging ratio of the raw material monomer. Is.
• the polymer a can be produced by copolymerizing the monomer mixture A by a known polymerization method.
• a solution polymerization method is preferable.
• the solvent used in the solution polymerization method is not limited, but water, polar solvents such as aliphatic alcohols having 1 to 3 carbon atoms, ketones, ethers and esters are preferable, and water, methanol, ethanol, acetone, methyl ethyl ketone and the like are preferable. Is more preferable, and methyl ethyl ketone is further preferable from the viewpoint of solubility of the polymer in a solvent.
• a polymerization initiator or a polymerization chain transfer agent can be used.
• the polymerization initiator include persulfates and water-soluble azo polymerization initiators, and persulfates such as ammonium persulfate and potassium persulfate are preferable.
• the polymerization chain transfer agent mercaptans are preferable, and 2-mercaptoethanol is more preferable.
• the polymerization temperature varies depending on the type of polymerization initiator, monomer, solvent and the like used, but is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and preferably 95 ° C. or lower, more preferably 80 ° C. or lower. is there.
• the polymerization atmosphere is preferably a nitrogen gas or an inert gas atmosphere.
• the produced polymer can be isolated from the reaction solution by a known method such as reprecipitation and solvent distillation.
• the polymer a is preferably neutralized with a neutralizing agent as described later.
• the weight average molecular weight of the polymer a is preferably 10,000 or more, more preferably 10,000 or more, from the viewpoint of improving the dispersion stability of the polymer-dispersed pigment in the ink and improving the fixability of the ink to the printing medium. It is 15,000 or more, and preferably 300,000 or less, more preferably 200,000 or less, still more preferably 100,000 or less.
• the acid value of the polymer a is preferably 50 mgKOH / g or more, more preferably 70 mgKOH / g or more, still more preferably 80 mgKOH / g or more, and from the viewpoint of the dispersibility of the pigment and the adsorptivity of the polymer to the pigment.
• It is preferably 300 mgKOH / g or less, more preferably 280 mgKOH / g or less, and further preferably 260 mgKOH / g or less.
• the weight average molecular weight and acid value can be measured by the method described in Examples.
• a commercially available polymer may be used as long as it has a structural unit derived from the component (a-1) and a structural unit derived from the component (a-2).
• Examples of commercially available vinyl polymers include "John Krill 67", “John Krill 611", “John Krill 678", “John Krill 680”, “John Krill 690”, and "John Krill 819” (above, BASF Japan).
• Styrene-acrylic resin such as (manufactured by Co., Ltd.) can be mentioned.
• the pigment-containing polymer particles are a method having the following step I and, if necessary, step II as a pigment dispersion A in which the pigment-containing polymer particles are dispersed in an aqueous medium. It is preferable to manufacture by.
• Step I After dissolving the polymer a in a solvent to obtain a solution of the polymer a, a pigment and, if necessary, a neutralizing agent, a surfactant and the like are added and mixed to obtain a pigment dispersion A composed of a pigment mixture.
• the solvent contains an organic solvent in Step I.
• Step II A step of removing the organic solvent from the pigment mixture obtained in Step I to obtain a pigment dispersion A.
• Step III A step of mixing the pigment dispersion A obtained in Step I or Step II with the cross-linking agent a to obtain cross-linked pigment-containing cross-linked polymer particles.
• the pigment dispersion A contains a pigment. It means both the polymer particles to be dispersed in an aqueous medium and the pigment-containing crosslinked polymer particles dispersed in an aqueous medium.
• the solvent for dissolving the polymer a is not limited, but from the viewpoint of wettability to the pigment, solubility of the polymer a, and adsorptivity to the pigment, water, an aliphatic alcohol having 1 or more and 3 or less carbon atoms. , One or more selected from ketones, ethers, esters and the like is preferable, one or more selected from water and ketones is more preferable, and the combined use of water and ketones is further preferable.
• the solvent used in the polymerization may be used as it is.
• the polymer a is an anionic polymer
• a neutralizing agent to neutralize the anionic groups in the polymer a.
• a neutralizing agent examples include bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, and various amines.
• the polymer a may be neutralized in advance.
• the degree of neutralization of the anionic group of the polymer a is the ratio of the molar equivalent of the neutralizing agent to the molar equivalent of the anionic group of the polymer a, preferably 30 mol, from the viewpoint of improving the storage stability of the ink of the present invention. % Or more, more preferably 40 mol% or more, still more preferably 50 mol% or more, and preferably 300 mol% or less, more preferably 200 mol% or less, still more preferably 150 mol% or less.
• step I it is preferable to apply mechanical force to the obtained pigment mixture for dispersion treatment.
• the method for applying the mechanical force is not particularly limited, and examples thereof include the method described in paragraph [0032] of JP-A-2018-83938.
• a media type disperser is preferable from the viewpoint of efficiently reducing the particle size of the pigment.
• the pigment can be adjusted to have a desired particle size by controlling the dispersion pressure and the like.
• Step II is an arbitrary step, but when the solvent contains an organic solvent in step I, the step II is a step of removing the organic solvent from the pigment mixture obtained in step I to obtain a pigment dispersion A containing water. .. It is preferable that the organic solvent in the obtained pigment dispersion A is substantially removed, but it may remain as long as the object of the present invention is 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 average particle size of the polymer particles containing the pigment in the pigment dispersion A is high-definition printing from the viewpoint of improving storage stability. From the viewpoint of this, it is preferably 50 nm or more, more preferably 100 nm or more, further preferably 120 nm or more, and preferably 350 nm or less, more preferably 320 nm or less, still more preferably 300 nm or less. Even when the cross-linking treatment is performed in step III below, the average particle size of the pigment-containing cross-linked polymer particles in the obtained pigment dispersion A is equivalent to the average particle size of the pigment-containing polymer particles. The average particle size is measured by the method described in Examples.
• Step III is a step of mixing the pigment dispersion A obtained in Step I or Step II with the cross-linking agent a to obtain cross-linked pigment-containing cross-linked polymer particles.
• a part of the carboxy group of the polymer a constituting the polymer particles containing the pigment is crosslinked, a crosslinked structure is formed in a part or all of the surface layer portion of the polymer particles containing the pigment, and the pigment is contained.
• the crosslinked polymer particles can be pigment-containing crosslinked polymer particles.
• the cross-linking agent a is preferably a compound having a functional group capable of reacting with the anionic group, and a compound having 2 or more and 6 or less the functional group in the molecule is preferable. More preferred.
• the cross-linking agent a include a compound having two or more epoxy groups in the molecule, a compound having two or more oxazoline groups in the molecule, a compound having two or more isocyanate groups in the molecule, and the like.
• water-soluble ratio means the dissolution ratio (mass%) when 10 parts by mass of the cross-linking agent is dissolved in 90 parts by mass of ion-exchanged water at 25 ° C.
• the cross-linking rate of the pigment-containing polymer particles in Step III is the ratio of the molar equivalents of the crosslinkable functional groups of the cross-linking agent to the molar equivalents of the carboxy groups of the polymer a from the viewpoint of improving storage stability and blocking resistance. It is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more, and preferably 80 mol% or less, more preferably 70 mol% or less, still more preferably 60 mol% or more. Below, it is even more preferably 50 mol% or less.
• the temperature of the crosslinking treatment is preferably 40 ° C. or higher, more preferably 55 ° C. or higher, and preferably 95 ° C. or lower, more preferably 80 ° C. or lower, from the viewpoint of completion of the crosslinking reaction and economic efficiency.
• the solid content concentration of the pigment dispersion A is preferably 10% by mass or more, more preferably 15% by mass or more, and from the viewpoint of improving the dispersion stability of the pigment dispersion and facilitating ink production, and It is preferably 45% by mass or less, more preferably 40% by mass or less.
• the solid content concentration is measured by the method described in Examples.
• the content of the pigment in the pigment dispersion A is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 45% by mass. % Or less, more preferably 40% by mass or less, still more preferably 35% by mass or less.
• the mass ratio [crosslinked polymer a / pigment] of the crosslinked polymer a and the pigment constituting the pigment-containing crosslinked polymer particles A in the pigment dispersion A is preferably 0.1 or more, more preferably 0.15 or more, and , Preferably 0.8 or less, more preferably 0.5 or less.
• the ink of the present invention contains crosslinked polymer particles containing no pigment (hereinafter, also referred to as “crosslinked polymer particles B”) from the viewpoint of suppressing tone jumping of the obtained printed matter and improving blocking resistance.
• the crosslinked polymer particles B are crosslinked polymer particles obtained by crosslinking polymer particles made of the polymer b described later, and do not contain a pigment.
• the polymer b before cross-linking may be a water-soluble polymer or a water-insoluble polymer, but the polymer becomes water-insoluble when cross-linked.
• water-insoluble is the same as the definition in the polymer a.
• the polymer b include vinyl-based polymers, urethane-based polymers, polyester-based polymers, and the like. Among these, vinyl-based polymers are preferable from the viewpoint of improving the drying property on the print medium and improving the blocking resistance.
• (Polymer b) When the polymer b is a vinyl-based polymer, (b-1) ionic monomer (hereinafter, also referred to as “(b-1) component”) and (b-2) hydrophobic monomer (hereinafter, “(b-2))
• (b-1) ionic monomer hereinafter, also referred to as “(b-1) component”
• (b-2) hydrophobic monomer hereinafter, “(b-2)
• a water-insoluble vinyl-based polymer obtained by copolymerizing a "monomer mixture B" containing also referred to as a "component"
• the water-insoluble vinyl-based polymer has a structural unit derived from the component (b-1) and a structural unit derived from the component (b-2).
• Examples of the component (b-1) include the same components as the component (a-1). Among them, an anionic monomer is preferable, a carboxylic acid monomer is more preferable, and one or more selected from acrylic acid and methacrylic acid is further preferable, from the viewpoint of improving the dispersion stability of the crosslinked polymer particles B in the ink of the present invention. ..
• Examples of the component (b-2) include the same components as the component (a-2). Among these, one or more selected from alkyl (meth) acrylates having an alkyl group having 1 or more and 22 or less carbon atoms, styrene, ⁇ -methylstyrene, and benzyl (meth) acrylate is preferable.
• the monomer components contained in each component can be used alone or in combination of two or more.
• the content of the components (b-1) and (b-2) in the monomer mixture B during the production of the polymer b (content as an unneutralized amount; the same applies hereinafter) or (b-1) and in the polymer b.
• the content of the structural unit derived from the component (b-2) is as follows.
• the content of the component (b-1) is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, still more preferably 7% by mass or more, and preferably 30.
• the content of the component (b-2) is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 85% by mass. It is more than 99% by mass, more preferably 97% by mass or less, still more preferably 95% by mass or less, still more preferably 93% by mass or less.
• the mass ratio of the component (b-1) to the component (b-2) [(b-1) / (b-2)] is preferably 0.01 or more, more preferably 0.05 or more, still more preferable. Is 0.1 or more, and preferably 0.6 or less, more preferably 0.55 or less, still more preferably 0.5 or less.
• the polymer b is produced by copolymerizing the monomer mixture B by a known polymerization method.
• the polymerization method include an emulsion polymerization method and a suspension polymerization method, but the emulsion polymerization method is preferable.
• a polymerization initiator can be used.
• the polymerization initiator include persulfates and water-soluble azo polymerization initiators, but persulfates such as ammonium persulfate and potassium persulfate are preferable.
• a nonionic, anionic, cationic or the like surfactant can be used, but an anionic surfactant is preferable from the viewpoint of improving the dispersion stability of the polymer particles.
• anionic surfactant include fatty acid salts, alkylbenzene sulfonates, polyoxyethylene alkyl ether sulfates and the like.
• the polymer b can also be obtained by a so-called solution polymerization method in which the polymerization is carried out in the presence of the monomer mixture B and the solvent that dissolves the polymer b.
• known solvents such as alcohol, ketone, and hydrocarbon can be used as the solvent.
• the polymer b is preferably neutralized with a neutralizing agent.
• the neutralizing agent include alkali metal hydroxides, ammonia, organic amine compounds and the like, with preference given to sodium hydroxide and dimethylaminoethanol.
• the degree of neutralization of the anionic group of the polymer b is the ratio of the molar equivalent of the neutralizing agent to the molar equivalent of the anionic group of the polymer b, preferably 10 mol%, from the viewpoint of the dispersion stability of the crosslinked polymer particles B. As mentioned above, it is more preferably 30 mol% or more, and preferably 150 mol% or less, more preferably 120 mol% or less.
• the method for forming the crosslinked structure of the crosslinked polymer particles B is not particularly limited.
• a polymer b is obtained by copolymerizing a monomer mixture B containing a crosslinkable monomer in addition to the components (b-1) and (b-2) to obtain crosslinked polymer particles B.
• a crosslinked structure can be formed during the preparation of.
• the crosslinkable monomer a compound having two or more vinyl groups in one molecule is preferable.
• a monomer mixture B'containing the components (b-1) and (b-2) and not containing the crosslinkable monomer is copolymerized to obtain a water-insoluble vinyl polymer, and then the water is obtained.
• Examples thereof include a method of forming a crosslinked structure by reacting a crosslinking agent b that reacts with a functional group of the insoluble vinyl polymer with the water-insoluble vinyl polymer.
• a crosslinking agent b when the component (b-1) is a carboxylic acid, a compound having two or more epoxy groups in one molecule is preferable.
• method (ii) is preferable from the viewpoint of convenience in producing the crosslinked polymer particles B.
• the crosslinked polymer particles B are preferably blended in the ink of the present invention as a dispersion of the crosslinked polymer particles B, preferably an aqueous dispersion.
• the method of using the polymer b as an aqueous dispersion of the crosslinked polymer particles B Specifically, a method of converting an organic solvent solution of the polymer b into an aqueous dispersion by a phase inversion emulsion method, a method of using the polymer b obtained by emulsion polymerization as it is, and a method of making the polymer b an aqueous solution and then dissolving the polymer b in water. Examples thereof include a method of forming an aqueous dispersion by reducing the property.
• the average particle size of the crosslinked polymer particles B used in the ink of the present invention in the aqueous dispersion is preferably 10 nm or more, more preferably 20 nm or more, still more preferably 30 nm or more from the viewpoint of ensuring the storage stability of the ink of the present invention. Yes, and it is preferably 300 nm or less, more preferably 200 nm or less, still more preferably 150 nm or less, still more preferably 100 nm or less.
• the average particle size of the crosslinked polymer particles B is measured by the method described in Examples.
• the weight average molecular weight of the polymer b constituting the crosslinked polymer particles B is difficult to measure due to the crosslinked structure, but it is preferable when the portion dissolved in the solvent shown in the molecular weight measurement method by GPC described in the examples is measured. Is 200,000 or more, more preferably 300,000 or more, further preferably 400,000 or more, and preferably 2.5 million or less, more preferably 1 million or less, still more preferably 600,000 or less.
• the acid value of the crosslinked polymer constituting the crosslinked polymer particles B is preferably 10 mgKOH / g or more, more preferably 50 mgKOH / g or more, still more preferably 100 mgKOH / g or more, and It is preferably 300 mgKOH / g or less, more preferably 250 mgKOH / g or less, still more preferably 200 mgKOH / g or less.
• the weight average molecular weight and acid value of the polymer are measured by the method described in Examples.
• the polymer a constituting the polymer particles containing the pigment and the polymer b constituting the crosslinked polymer particles B may be the same or different.
• the cross-linking agent a and the cross-linking agent b may be the same or different. That is, the polymers a and b may have different compositions, or may be the same polymer including the composition, and may differ only in the presence or absence of the pigment. A commercially available product may be used as the polymer b.
• the water-based ink for plate printing of the present invention contains a water-soluble organic solvent having a boiling point of 100 ° C. or higher and 260 ° C. or lower from the viewpoint of suppressing tone jumping of the obtained printed matter and improving blocking resistance.
• the "water-soluble organic solvent” refers to an organic solvent having a dissolution amount of 10 ml or more when the organic solvent is dissolved in 100 ml of water at 25 ° C., and is liquid at room temperature (25 ° C.). May also be solid.
• the boiling point of the water-soluble organic solvent is preferably 110 ° C. or higher, more preferably 115 ° C. or higher, still more preferably 120 ° C.
• the temperature is preferably 250 ° C. or higher, more preferably 150 ° C. or higher, and from the viewpoint of improving blocking resistance, preferably 250 ° C. or lower, more preferably 245 ° C. or lower, still more preferably 240 ° C. or lower, still more preferably 235 ° C.
• the "boiling point” means a standard boiling point (boiling point under 1 atm), and the boiling point is measured according to JIS K2254.
• the boiling point value is a weighted average value weighted by the content (mass%) of each water-soluble organic solvent.
• the water-soluble organic solvent (C) preferably contains glycol ether from the viewpoint of suppressing tone jumping of the obtained printed matter and improving blocking resistance.
• the molecular weight of the glycol ether is preferably 70 or more, more preferably 80 or more, still more preferably 100 or more, and preferably 200 or less, more preferably 190 or less, still more preferably 180 or less.
• the boiling point of glycol ether is preferably 110 ° C. or higher, more preferably 115 ° C. or higher, still more preferably 120 ° C. or higher, still more preferably 130 ° C. or higher, still more preferably 140 ° C. or higher, and more. It is more preferably 150 ° C. or higher, and preferably 250 ° C. or lower, more preferably 245 ° C. or lower, still more preferably 240 ° C. or lower, still more preferably 235 ° C. or lower.
• glycol ether one or more selected from alkylene glycol monoalkyl ethers and alkylene glycol dialkyl ethers are preferable, and alkylene glycol monoalkyl ethers are more preferable.
• the alkyl group of the glycol ether has 1 or more carbon atoms, preferably 2 or more carbon atoms, and preferably 6 or less, more preferably 4 or less, and further preferably 3 or less.
• the alkyl group may be a straight chain or a branched chain.
• alkylene glycol monoalkyl ether examples include ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, and ethylene glycol monoisobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoisopropyl ether, and diethylene glycol monobutyl ether.
• Diethylene glycol monoalkyl ether such as diethylene glycol monoisobutyl ether; propylene glycol monoalkyl ether such as propylene glycol monomethyl ether and propylene glycol monopropyl ether; Dipropylene glycol monoalkyl ether such as dipropylene glycol monomethyl ether; tripropylene glycol monomethyl ether and the like Examples include tripropylene glycol monoalkyl ether.
• Examples of the alkylene glycol dialkyl ether include diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and triethylene glycol dimethyl ether. These can be used alone or in combination of two or more.
• ethylene glycol monomethyl ether 125 ° C
• ethylene glycol monoisopropyl ether 142 ° C
• ethylene glycol monobutyl ether 171 ° C
• diethylene glycol monoisopropyl ether 207 ° C
• diethylene glycol monobutyl ether 230 ° C
• diethylene glycol monoisobutyl ether 220 ° C
• dipropylene glycol monomethyl ether 187 ° C
• tripropylene glycol monomethyl ether tripropylene glycol monomethyl ether.
• diethylene glycol dimethyl ether (162 ° C.), diethylene glycol methyl ethyl ether (176 ° C.), and diethylene glycol diethyl ether (189 ° C.) are preferably one or more, preferably ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, and ethylene glycol. More preferably, one or more selected from monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether and diethylene glycol monoisobutyl ether.
• the numerical value in parentheses is the boiling point.
• the water-soluble organic solvent may contain a water-soluble organic solvent other than glycol ether.
• examples of other water-soluble organic solvents include dihydric or higher polyhydric alcohols such as alcohols and glycols, and cyclic amide compounds such as N-methyl-2-pyrrolidone and 2-pyrrolidone, but contain only glycol ethers. Is preferable.
• the ink of the present invention may contain a water-soluble organic solvent having a boiling point of less than 100 ° C. or a water-soluble organic solvent having a boiling point of more than 260 ° C., as long as the effects of the present invention are not impaired. Examples of the water-soluble organic solvent having a boiling point of less than 100 ° C.
• Examples of the water-soluble organic solvent having a boiling point exceeding 260 ° C. include triethylene glycol (boiling point 285 ° C.), tripropylene glycol (boiling point 273 ° C.), and glycerin (boiling point 290 ° C.).
• the water-based ink for plate printing of the present invention preferably further contains a surfactant from the viewpoint of suppressing tone jumping of the obtained printed matter and improving blocking resistance.
• a surfactant examples include anionic surfactants, nonionic surfactants, amphoteric surfactants and the like, but nonionic surfactants are preferable, and acetylene glycol-based surfactants and silicone-based surfactants are selected. It is more preferable to use one or more of them, and it is more preferable to use an acetylene glycol-based surfactant and a silicone-based surfactant in combination.
• the acetylene glycol-based surfactant is preferably acetylene glycol having 8 or more and 22 or less carbon atoms and an ethylene oxide adduct thereof, and more preferably acetylene glycol having 8 or more and 22 or less carbon atoms.
• the carbon number of the acetylene glycol is preferably 10 or more, more preferably 12 or more, and preferably 20 or less, more preferably 18 or less, still more preferably 16 or less.
• the HLB (hydrophilic lipophilic balance) value of the acetylene glycol-based surfactant is preferably 0 or more, more preferably 1 or more, still more preferably 2 or more, still more preferably 2.5 or more, and preferably. It is 5.5 or less, more preferably 5.0 or less, still more preferably 4.5 or less.
• the HLB value can be obtained by the Griffin method.
• acetylene glycol-based surfactant examples include 2,4,7,9-tetramethyl-5-decine-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3 , 5-Dimethyl-1-hexin-3-ol, 2,4-dimethyl-5-hexin-3-ol, 2,5-dimethyl-3-hexyne-2,5-diol, 2,5,8,11
• Examples of commercially available products include acetylene-based diols such as -tetramethyl-6-dodecine-5,8-diol and their ethylene oxide adducts, and examples of commercial products thereof include "Surfinol" series manufactured by Air Products and Chemicals.
• Examples include the "Orphin” series and the “Acetyleneol” series manufactured by Kawaken Fine Chemicals Co., Ltd.
• Surfinol 104 (2,4,7,9-tetramethyl-5-decine-4,7-diol, HLB: 3)
• 104E (50% diluted ethylene glycol of Surfinol 104), the same.
• 104PG-50 (50% dilution of propylene glycol of Surfinol 104), Surfinol 420 (Eo average 1.3 mol addition of Surfinol 104, HLB: 4.7), Acetyleneol E13T (EO average addition molar number: 1) .3, HLB: 4.7) and the like are preferable.
• silicone-based surfactant examples include dimethylpolysiloxane, polyether-modified silicone, amino-modified silicone, and carboxy-modified silicone. From the viewpoint of suppressing tone jump of the obtained printed matter and improving blocking resistance, poly Ether-modified silicone is preferred.
• the polyether-modified silicone has a structure in which the hydrocarbon groups at the side chains and / or terminals of the silicone oil are replaced with the polyether groups.
• polyether group a polyethyleneoxy group, a polypropyleneoxy group, a polyalkyleneoxy group in which an ethyleneoxy group (EO) and a propyleneoxy group (PO) are added in a block shape or at random are preferable, and a polyalkyleneoxy group is added to the silicone main chain.
• EO ethyleneoxy group
• PO propyleneoxy group
• a compound in which an ether group is grafted, a compound in which silicone and a polypropylene group are bonded in a block shape, and the like can be used.
• the HLB value of the polyether-modified silicone-based surfactant is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more.
• Specific examples of the polyether-modified silicone include PEG-3 dimethicone, PEG-9 dimethicone, PEG-9 PEG-9 dimethicone, PEG-9 methyl ether dimethicone, PEG-10 dimethicone, PEG-11 methyl ether dimethicone, and PEG / PPG-.
• butyl ether dimethicone, PEG-32 methyl ether dimethicone, PEG-9 polydimethylsiloxyethyl dimethicone, lauryl PEG-9 polydimethylsiloxyethyl dimethicone and the like can be mentioned, and among these, PEG-11 methyl ether dimethicone is preferable.
• Examples of commercially available products of polyether-modified silicones include silicones from Shin-Etsu Chemical Co., Ltd .: KF-6011, KF-6012, KF-6013, KF-6015, KF-6016, KF-6017, KF-6028, KF-6038. , KF-6043 and the like.
• the water-based ink for plate printing of the present invention comprises a pigment, preferably a pigment-containing polymer particle, more preferably the pigment dispersion A, and a pigment-free crosslinked polymer particle B, preferably a pigment-free crosslinked polymer particle B. It can be efficiently produced by mixing the aqueous dispersion of the above, a water-soluble organic solvent, a surfactant, and other organic solvents, if necessary. There is no particular limitation on the method of mixing them. Further, the ink of the present invention may be used as it is by adjusting each component to the content and density at the time of printing, and the base ink prepared in advance is diluted with water or the like to adjust the content and density at the time of printing. May be used.
• the content and physical properties of each component of the water-based ink for plate printing of the present invention are as follows.
• the content of each component in the ink is the content at the time of printing.
• the content of the pigment in the ink of the present invention is 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, from the viewpoint of printing density, and , 15% by mass or less, preferably 13% by mass or less, more preferably 10% by mass or less, still more preferably 9% by mass or less.
• the content of the pigment-containing polymer particles in the ink of the present invention is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass or more, and storage, from the viewpoint of improving the printing density. From the viewpoint of improving stability, it is preferably 25% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less.
• the content of the polymer a in the ink of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.5% by mass, from the viewpoint of suppressing the tone jump of the obtained printed matter.
• the mass ratio of the polymer a to the pigment in the ink of the present invention is preferably 0.06 or more, more preferably 0.1 or more, still more preferably 0, from the viewpoint of improving the storage stability of the ink. It is .15 or more, more preferably 0.18 or more, and preferably 1 or less, more preferably 0.8 or less, still more preferably 0.7 or less, still more preferably 0.5 or less.
• the mass of the polymer a means the mass including the mass of the cross-linking agent a component.
• the content of the crosslinked polymer particles B in the ink of the present invention is 1% by mass or more, preferably 2% by mass or more, more preferably 2% by mass or more, from the viewpoint of suppressing tone jump of the obtained printed matter and improving the blocking resistance.
• the mass ratio of the polymer to the pigment in the ink of the present invention is preferably 0.2 or more, more preferably 0.4 or more, still more preferably 0.6 or more, from the viewpoint of ink stability. It is more preferably 0.8 or more, and preferably 4 or less, more preferably 3 or less, still more preferably 2 or less, still more preferably 1.8 or less.
• the amount of the polymer in the mass ratio [polymer / pigment] is the total amount of the polymer a and the polymer b. At this time, if both the polymer a and the polymer b are neutralized, the mass including the neutralizing agent is calculated.
• the content of the water-soluble organic solvent having a boiling point of 100 ° C. or higher and 260 ° C. or lower in the ink of the present invention is 1% by mass or more, preferably 1% by mass or more, from the viewpoint of suppressing tone jump of the obtained printed matter and improving blocking resistance. It is 2% by mass or more, more preferably 3% by mass or more, and 15% by mass or less, preferably 10% by mass or less, more preferably 9% by mass or less, still more preferably 8% by mass or less. From the same viewpoint as above, the content of glycol ether having a boiling point of 100 ° C. or higher and 260 ° C.
• the ink or lower in the ink of the present invention is preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 3% by mass or more. Yes, and preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 9% by mass or less, still more preferably 8% by mass or less.
• the mass ratio of the glycol ether to the total amount of the water-soluble organic solvent in the ink of the present invention [glycol ether / total amount of water-soluble organic solvent] is preferably 0.5 or more, more preferably 0.6 or more, still more preferably 0. It is 0.7 or more, and preferably 1 or less.
• the ink may contain an organic solvent having a boiling point of less than 100 ° C.
• the amount is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, still more preferably 0%.
• the content of the surfactant in the ink of the present invention is preferably 0.1% by mass or more, more preferably 0., From the viewpoint of improving the wettability to the printing medium, tone jump and blocking resistance. It is 2% by mass or more, more preferably 0.5% by mass or more, and preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less. From the same viewpoint as above, the content of the acetylene glycol-based surfactant in the ink of the present invention is preferably 0.2% by mass or more, more preferably 0.4% by mass or more, still more preferably 0.6% by mass.
• the content of the silicone-based surfactant in the ink of the present invention is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, still more preferably 0.05% by mass or more. And, preferably 3% by mass or less, more preferably 2% by mass or less, still more preferably 1% by mass or less.
• the mass ratio of the acetylene glycol-based surfactant in the ink of the present invention to the total amount of the surfactant [acetylene glycol-based surfactant / total amount of surfactant] is preferably 0.1 or more, more preferably 0.3 or more, and further. It is preferably 0.5 or more, and preferably 1 or less.
• the content of water in the ink of the present invention is preferably 60% by mass or more, more preferably 65% by mass or more, further preferably 70% by mass or more, and the print density is adjusted. From the viewpoint of securing, it is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less.
• the ink contains other optional components such as (A) pigment, (B) crosslinked polymer particles, (C) water-soluble organic solvent and water, such as a surfactant, a part of the water content is added. It can be contained in place of other components.
• the ink of the present invention can contain various additives such as a pH adjuster, a viscosity adjuster, an antifoaming agent, a preservative, and a rust preventive as optional components depending on the intended use.
• the three viscosities (outflow time (seconds)) are preferably 10 seconds or longer, more preferably 12 seconds or longer, still more preferably 14 seconds or longer, from the viewpoint of suppressing tone jump of the obtained printed matter and improving blocking resistance. Yes, and preferably 25 seconds or less, more preferably 23 seconds or less, still more preferably 20 seconds or less.
• the pH of the ink of the present invention at 20 ° C. is preferably 5.5 or more, more preferably 6.0 or more, still more preferably 6.5 or more, and member resistance, skin, from the viewpoint of improving dispersion stability. From the viewpoint of irritation, it is preferably 11 or less, more preferably 10 or less, still more preferably 9 or less.
• the ink of the present invention is preferably used for gravure printing because tone jump is unlikely to occur and it has excellent blocking resistance.
• the plate printing method of the present invention is a method of printing on a low liquid absorption printing medium using the water-based ink of the present invention.
• Examples of plate printing include gravure printing using printing plates such as intaglio, flat plate, and letterpress, flexographic printing, and letterpress printing.
• the ink is supplied to the surface of the gravure cylinder while rotating a gravure cylinder (gravure plate) in which concave cells are formed on the surface, and the ink is scraped off by a doctor fixed at a predetermined position to make ink only in the cells.
• the print medium that is continuously supplied is crimped to the gravure cylinder with an impression cylinder whose surface is made of rubber, and only the ink in the cell of the gravure cylinder is transferred to the print medium to transfer characters and images.
• This is the method of printing.
• the ink of the present invention does not need to be diluted with a solvent when printing, and the upper limit of the total amount of the water-soluble organic solvent having a boiling point of 100 ° C. or higher and 260 ° C. or lower contained in the ink is 15% by mass, so that the environmental load is reduced. it can.
• Examples of the low liquid absorption printing medium used in the plate printing method of the present invention include processed paper, synthetic paper, art paper, low liquid absorption coated paper, resin film and the like.
• Examples of the coated paper include general-purpose glossy paper and multicolor foam gloss paper.
• Examples of the resin film include a transparent synthetic resin film, and examples thereof include a resin film made of polyester, polypropylene, polyethylene, polystyrene, polyvinyl chloride, polyamide and the like.
• a resin film is preferable from the viewpoint of developing into packaging applications and increasing the printing density, and a polyester film and a polypropylene film are preferable from the viewpoint of post-processing suitability such as punching after printing.
• These resin films may be a biaxially stretched film, a uniaxially stretched film, or a non-stretched film.
• a corona-discharge-treated polyethylene terephthalate (PET) film and a corona-discharge-treated biaxially stretched polypropylene (OPP) film are more preferable from the viewpoint of improving gravure printability.
• PStQuick B F-550, F-80, F-10, F-1, A-1000
• PStQuick C F-288, F-40, F-4, A-5000, A-500
• Tosoh Corporation Known monodisperse polystyrene kits
• 0.1 g of the polymer was mixed with 10 mL of the eluent in a glass vial, stirred at 25 ° C. for 10 hours with a magnetic stirrer, and a syringe filter (DISMIC-13HP, made of PTFE, 0.2 ⁇ m, Advantech Co., Ltd.) was used. The one filtered by the company) was used.
• Production Example 1 (Production of polymer particles containing (A) pigment) (1) Weigh 236 parts of ion-exchanged water in a 2L flask, and weigh a styrene-acrylic polymer (manufactured by BASF, trade name: John Krill 690, solid content concentration 20%, weight average molecular weight: 16500, acid value: 240 mgKOH / g). ) 60 parts, 36.5 parts of 5N sodium hydroxide solution (sodium neutralization degree 60 mol%) was added. The mixture was stirred at 200 rpm for 2 hours using an anchor blade to obtain 332.5 parts of a polymer aqueous solution (solid content concentration 19.9%).
• Production Example 2 ((B) Production of crosslinked polymer particles containing no pigment) 172.8 parts of ion-exchanged water was weighed in a 2 L flask, and 60 parts of the styrene-acrylic polymer (manufactured by BASF, trade name: John Krill 690) used in Production Example 1 and dimethylaminoethanol (neutralizer) 13. 7 parts (neutralization degree 60 mol%) were added. The mixture was stirred at 200 rpm for 2 hours using an anchor blade to obtain 246.5 parts (solid content concentration 29.9%) of an aqueous dispersion of polymer particles containing no pigment.
• styrene-acrylic polymer manufactured by BASF, trade name: John Krill 690
• Production Example 3 (Production of non-crosslinked polymer particles containing no pigment) A part of the aqueous dispersion (solid content concentration 29.9%) of the pigment-free polymer particles, which is in the process of producing the pigment-free crosslinked polymer particles of Production Example 2, is partially extracted and contains the pigment. Obtained as an aqueous dispersion of non-crosslinked polymer particles.
• Example 1 (Preparation of water-based ink 1) (A) 29.3 parts of polymer particles containing a pigment (corresponding to a pigment concentration of 7.3% in ink) in the form of the aqueous dispersion obtained in Production Example 1, and water obtained in Production Example 2.
• Example 2-9, Comparative Examples 1-5 Preparation of water-based inks 2-9, 11-15
• Example 1 water-based inks 2 to 9 and 11 to 15 were obtained in the same manner as in Example 1 except that the ink composition was changed as shown in Table 1. The results are shown in Table 1.
• Example 10 (Preparation of water-based ink 10) Cab-O-Jet 300 (manufactured by Cabot Specialty Chemicals Co., Ltd .: solid content 15%) 48.7 parts (equivalent to a pigment concentration of 7.3% in ink) as a pigment dispersion containing a self-dispersing pigment in a container.
• ⁇ Evaluation of tone jump> The reflection density of the gradation portion of the obtained printed matter in 10% increments was measured with an optical densitometer SpectroEye (manufactured by Gretag Macbeth). A state in which the reflection density between gradations was 0.2 or more was defined as a tone jump, and the state of the tone jump was evaluated according to the following criteria. (Evaluation criteria) 5: Printed matter without tone jump. 4: Printed matter with tone jumps seen from 50% cells. 3: Tone jump can be seen from the cell in the printed matter by 60%. 2: Printed matter with tone jumps seen from 70% cells. 1: Printed matter with tone jumps seen from 80% cells. If the evaluation result is 3 or more, there is no problem in practical use of tone jump.
• the water-based inks of Examples are less likely to cause tone jump even with a low liquid absorption printing medium as compared with the water-based inks 11 to 15 of Comparative Examples, and have blocking resistance. It turns out that it is excellent in.
• the water-based ink for plate printing of the present invention it is possible to obtain a printed matter having excellent blocking resistance because tone jump is less likely to occur even on a low liquid absorption printing medium.
• the water-based ink for plate printing of the present invention is particularly useful for gravure printing.

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