Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/02—Printing inks
  • C09D11/10—Printing inks based on artificial resins
  • C09D11/101—Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the 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
  • C09D11/30—Inkjet printing inks

Definitions

• This disclosure relates to inkjet inks and image recording methods.
• an image recording method in which ink is applied onto a recording medium and the applied ink is irradiated with active energy rays such as ultraviolet rays to cure the ink to obtain an image.
• active energy rays such as ultraviolet rays
• Japanese Patent Application Laid-Open No. 2018-024757 contains a photopolymerizable compound, a photopolymerization initiator, and an inorganic filler having an average particle size of 1 nm to 200 nm in an amount of 0.05% by mass to 5.0% by mass in the composition.
• a clear ink composition for photocurable ink jet printing having a visible light transmittance of 30% or more is described.
• Japanese Patent Application Laid-Open No. 2019-162742 describes an active energy ray-curable composition containing fine particles having an average primary particle size of 100 nm to 200 nm.
• Japanese Patent Application Laid-Open No. 2020-62758 contains an ultraviolet curable ink containing 1% by mass to 10% by mass of silica particles having an average primary particle size of 7 nm to 16 nm whose surface is surface-modified with dimethylsilyl or dimethylpolysiloxane. Have been described.
• images recorded using active energy ray-curable ink may have strong gloss. Due to the strong gloss, the above image may have a relief feeling or may be conspicuous. Therefore, from the viewpoint of reducing the relief feeling of the image, making the image inconspicuous, and the like, it may be required that the gloss is suppressed as the quality of the image recorded by using the active energy ray-curable ink. .. However, if the ink contains a gloss suppressing component in order to suppress the gloss, the ejection property may be deteriorated when the ink is ejected by the inkjet recording method.
• an inkjet ink capable of recording an image having excellent ejection properties and suppressed gloss, and an image recording method using the inkjet ink.
• the disclosure includes the following aspects: ⁇ 1> An inkjet ink containing a radically polymerizable monomer and silica particles, wherein the silica particles have an average primary particle size of 22 nm or more and less than 100 nm, and a degree of hydrophobicity of 50 or more.
• the silica particles are described in ⁇ 1> or ⁇ 2>, wherein the product of the average primary particle size when the unit is nm and the specific surface area when the unit is m 2 / g is 2400 or less. Inkjet ink.
• ⁇ 4> The inkjet ink according to any one of ⁇ 1> to ⁇ 3>, wherein the silica particles have a degree of hydrophobicity of 70 or more.
• ⁇ 5> The inkjet ink according to any one of ⁇ 1> to ⁇ 4>, wherein the content of the silica particles is 1% by mass to 10% by mass with respect to the total amount of the inkjet ink.
• the radically polymerizable monomer contains at least one of a monofunctional radically polymerizable monomer and a bifunctional radically polymerizable monomer, and the total content of the monofunctional radically polymerizable monomer and the bifunctional radically polymerizable monomer is the amount of the inkjet ink.
• the inkjet ink according to any one of ⁇ 1> to ⁇ 5> which is 50% by mass or more with respect to the total amount.
• ⁇ 7> The inkjet ink according to any one of ⁇ 1> to ⁇ 6>, wherein the radically polymerizable monomer contains a radically polymerizable monomer having a ClogP value of 2 or more.
• ⁇ 8> The inkjet ink according to ⁇ 7>, wherein the mass ratio of the content of the radically polymerizable monomer having a ClogP value of 2 or more to the content of the silica particles is 6 to 50.
• ⁇ 9> The inkjet ink according to any one of ⁇ 1> to ⁇ 8>, wherein the radically polymerizable monomer contains an N-vinyl compound.
• ⁇ 10> The inkjet ink according to ⁇ 9>, wherein the mass ratio of the content of the N-vinyl compound to the content of the silica particles is 1 to 8.
• ⁇ 11> The inkjet ink according to any one of ⁇ 1> to ⁇ 10>, wherein the radically polymerizable monomer contains a vinyl ether compound.
• ⁇ 12> A step of applying the inkjet ink according to any one of ⁇ 1> to ⁇ 11> onto a recording medium by an inkjet recording method to obtain an ink film, and irradiating the ink film with active energy rays.
• Process and Image recording method including.
• an inkjet ink capable of recording an image having excellent ejection properties and suppressed gloss, and an image recording method using the inkjet ink.
• the numerical range represented by using “-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
• the amount of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. do.
• the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Further, it may be replaced with the value shown in the embodiment.
• the term "process” is included in this term not only as an independent process but also as long as the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes.
• the combination of preferred embodiments is a more preferred embodiment.
• "light” is a concept including active energy rays such as ⁇ -rays, ⁇ -rays, electron rays, ultraviolet rays, and visible rays.
• ultraviolet rays may be referred to as "UV (Ultra Violet) light".
• (meth) acrylate is a concept including both acrylate and methacrylate
• (meth) acryloyl group is a concept including both acryloyl group and methacrylic acid group
• (meth) acrylate is included.
• “Acrylic acid” is a concept that includes both acrylic acid and methacrylic acid.
• the "image” means the entire film formed by using ink
• the “image recording” means the formation of an image (that is, a film).
• image means the formation of an image (that is, a film).
• image also includes a solid image.
• the inkjet ink of the present disclosure (hereinafter, simply referred to as “ink”) contains a radically polymerizable monomer and silica particles, and the silica particles have an average primary particle size of 22 nm or more and less than 100 nm, and have a degree of hydrophobicity of 50. That is all.
• the ink of the present disclosure it is possible to record an image having excellent ejection properties and suppressed gloss.
• the reason why the above effect is achieved is presumed as follows.
• ink is applied onto a recording medium, and active energy rays are applied to the ink applied onto the recording medium (hereinafter, also referred to as “ink film”). It is done by irradiating.
• the ink film is irradiated with active energy rays, the radically polymerizable monomers in the ink film are polymerized and the ink film is cured. As a result, an image that is a cured ink film is obtained.
• the ink of the present disclosure can be said to be an active energy ray irradiation type ink.
• the degree of hydrophobicity of silica particles is 50 or more. Therefore, the silica particles tend to be present on the surface of the ink film. Further, the average primary particle size of the silica particles is 22 nm or more and less than 100 nm. When silica particles of such a size gather on the surface of the ink film, it is considered that the aggregated silica particles function as a matting agent. It is considered that the gloss of the image is suppressed by curing the ink film with the silica particles gathered on the surface of the ink film.
• the average primary particle size of the silica particles is 22 nm or more, the increase in the viscosity of the ink is suppressed without increasing the surface area of the silica particles. As a result, the ink of the present disclosure is considered to be excellent in ejection property.
• the average primary particle size of the silica particles is less than 100 nm, the silica particles are less likely to settle, so that the ink of the present disclosure is considered to have excellent ejection properties.
• Japanese Patent Application Laid-Open No. 2018-024757 discloses an ink containing silica particles having an average particle size of 20 nm. This average particle size means a dispersed particle size, and the primary particle size is considered to be 20 nm or less. Further, Japanese Patent Application Laid-Open No. 2020-62758 contains an ultraviolet curable ink containing 1% by mass to 10% by mass of silica particles having an average primary particle size of 7 nm to 16 nm whose surface is surface-modified with dimethylsilyl or dimethylpolysiloxane. Have been described.
• the inks disclosed in JP-A-2018-024757 and JP-A-2020-626758 since the average primary particle size of the silica particles is small, the ink has a high viscosity, and as a result, good ejection properties cannot be obtained. it is conceivable that. Further, it is considered that the silica particles do not function as a matting agent because the average primary particle size is not in an appropriate range. Therefore, it is considered that the inks disclosed in JP-A-2018-024757 and JP-A-2020-062758 do not have the effect of suppressing gloss.
• Japanese Patent Application Laid-Open No. 2019-162742 describes an active energy ray-curable composition containing silica particles having an average primary particle size of 100 nm to 200 nm.
• the silica particles do not function as a matting agent because the average primary particle size is not in an appropriate range. Therefore, it is considered that the composition disclosed in JP-A-2019-162742 does not have the effect of suppressing gloss.
• the ink of the present disclosure contains at least one type of silica particles.
• the degree of hydrophobicity of the silica particles contained in the ink of the present disclosure is 50 or more. That is, the silica particles contained in the ink of the present disclosure are hydrophobic silica particles. Silica particles having a degree of hydrophobicity of 50 or more are likely to be present on the surface of the ink film, so that the gloss of the image is suppressed. Further, the silica particles having a degree of hydrophobicity of 50 or more act as a surfactant in the ink and reduce the surface tension of the ink. When the surface tension of the ink is small, the drip interference is suppressed and the image quality (particularly the graininess) is improved.
• the degree of hydrophobicity of the silica particles is more preferably 70 or more from the viewpoint of further suppressing the gloss of the obtained image and further improving the image quality.
• the upper limit of the degree of hydrophobicity of the silica particles is not particularly limited, and is, for example, 99.
• the degree of hydrophobicity of the silica particles is measured by the following method.
• the average primary particle size of the silica particles contained in the ink of the present disclosure is 22 nm or more and less than 100 nm.
• the average primary particle size of the silica particles is 22 nm or more, the increase in the viscosity of the ink is suppressed without increasing the surface area of the silica particles. As a result, the ink of the present disclosure is excellent in ejection property.
• the average primary particle size of the silica particles is less than 100 nm, the silica particles are less likely to settle, so that the ink of the present disclosure is excellent in ejection property.
• the average primary particle size of the silica particles is 22 nm or more and less than 100 nm, the silica particles collected on the surface of the ink film function as a matting agent, and the gloss of the image is suppressed.
• the average primary particle size of the silica particles is preferably 40 nm to 80 nm, more preferably 50 nm to 80 nm, from the viewpoint of further suppressing the gloss of the obtained image and further improving the ejection property.
• the average primary particle size of silica particles is a value measured using a transmission electron microscope (TEM).
• the average primary particle size of the silica particles can be measured, for example, using a transmission electron microscope (product name "1200EX") manufactured by JEOL Ltd.
• the specific measurement method is as follows.
• Ink diluted 1,000 times was dropped onto a Cu200 mesh (manufactured by JEOL Ltd.) to which a carbon film was attached and dried. Then, from the image magnified 100,000 times by TEM, the equivalent circle diameter of 300 independent particles that do not overlap is measured. The average value of the equivalent circle diameter obtained by the measurement is defined as the average primary particle size.
• the average secondary particle size of the silica particles contained in the ink of the present disclosure is preferably 200 nm to 800 nm, and more preferably 400 nm to 800 nm.
• the average secondary particle size of the silica particles is 200 nm to 800 nm, the presence of the silica particles on the surface of the ink film has a high effect of suppressing the gloss of the image.
• the secondary particle size means the size of the silica particles dispersed in the ink, and can be said to be the dispersed particle size.
• the silica particles may exist in the state of primary particles in the ink, or may exist in a state in which a plurality of primary particles are aggregated and aggregated. In the former case, the primary particle size and the secondary particle size have almost the same value.
• the average secondary particle size of the silica particles is a value measured using a particle size distribution measuring device.
• the average secondary particle size of the silica particles can be measured, for example, by using a particle size distribution measuring device (product name “LUMiSizer”) manufactured by LUM.
• the specific measurement method is as follows.
• Centrifugation is performed for 16 hours under the condition of a rotation speed of 3000 using a particle size distribution measuring device (product name "LUMiSizer") manufactured by LUM.
• the average value of the dispersed particle size obtained by the measurement is defined as the average secondary particle size.
• the silica particles contained in the ink of the present disclosure preferably have a product of the average primary particle size when the unit is nm and the specific surface area when the unit is m 2 / g is 2400 or less, and preferably 1800 or less. Is more preferable.
• the lower limit of the product is not particularly limited, and is, for example, 1000.
• the smaller the average primary particle size the higher the specific surface area.
• the higher the degree of agglomeration the lower the specific surface area. Therefore, the fact that the product of the average primary particle size and the specific surface area is 2400 or less means that the primary particles aggregate to some extent to form secondary particles. Therefore, when the product of the average primary particle size and the specific surface area of the silica particles is 2400 or less, the gloss of the image is suppressed.
• the specific surface area of the silica particles is a value measured by the BET method.
• the specific surface area of the silica particles can be measured, for example, using a rapid BET specific surface area measuring device (product name "BELSORP MR1") manufactured by Microtrac MRB.
• the specific measurement method is as follows.
• the specific surface area of the obtained silica particles is calculated from the filling amount of nitrogen gas using a rapid BET specific surface area measuring device.
• the silica particles may be fumed silica or colloidal silica as long as the average primary particle size is 22 nm or more and less than 100 nm.
• colloidal silica is monodisperse and does not easily aggregate. That is, the average primary particle size and the average secondary particle size tend to be almost the same value.
• fumed silica primary particles tend to be loosely aggregated to form secondary particles.
• the average secondary particle size of the silica particles is preferably 200 nm to 800 nm from the viewpoint of suppressing the gloss of the image. Therefore, the silica particles are preferably fumed silica.
• the surface structure of the silica particles is not particularly limited, but from the viewpoint of making the degree of hydrophobicity 50 or more, the silica particles preferably have a polydimethylsiloxane structure or an alkyl group, and preferably have a polydimethylsiloxane structure.
• the surface structure of the silica particles can be analyzed using a pyrolysis gas chromatograph, for example, QP2010 Ultra manufactured by Shimadzu Corporation.
• Silica particles may be commercially available products.
• Commercially available products include, for example, VP RY 40S, VP RX 40S (above, manufactured by Ebonic), Aerosil RY50, Aerosil RY51, Aerosil NY50, Aerosil RX50, Aerosil RX50, Aerosil NAX50, Aerosil ASilASilA
• the content of the silica particles is not particularly limited, but is preferably 0.5% by mass to 15% by mass, more preferably 1% by mass to 10% by mass, and 2.5% by mass with respect to the total amount of the ink. It is more preferably% to 8% by mass.
• the content of the silica particles is 0.5% by mass or more, the gloss of the image is further suppressed.
• the content of the silica particles is 15% by mass or less, the ejection property is further improved.
• the ink of the present disclosure contains at least one radically polymerizable monomer.
• the radically polymerizable monomer means a monomer having at least one radically polymerizable group in one molecule.
• the radically polymerizable group is preferably an ethylenically unsaturated group from the viewpoint of curability.
• the molecular weight of the radically polymerizable monomer is preferably 100 to 400.
• the molecular weight of the radically polymerizable monomer can be calculated based on the type and number of atoms constituting the radically polymerizable monomer.
• the radically polymerizable monomer includes a monofunctional radically polymerizable monomer (hereinafter referred to as "monofunctional monomer”), a bifunctional radically polymerizable monomer (hereinafter referred to as “bifunctional monomer”), and a trifunctional or higher functional radically polymerizable monomer (hereinafter referred to as “bifunctional monomer”).
• monofunctional radically polymerizable monomer hereinafter referred to as "monofunctional monomer”
• bifunctional radically polymerizable monomer hereinafter referred to as "bifunctional monomer”
• a trifunctional or higher functional radically polymerizable monomer hereinafter, it may be any of (referred to as "monomer having trifunctionality or higher”).
• the radically polymerizable monomer may be a combination containing two or more of a monofunctional monomer, a bifunctional monomer, and a trifunctional or higher functional monomer.
• the radically polymerizable monomer contained in the ink of the present disclosure preferably contains at least one of a monofunctional monomer and a bifunctional monomer.
• the total content of the monofunctional monomer and the bifunctional monomer is preferably 50% by mass or more, more preferably 55% by mass or more, and more preferably 60% by mass or more with respect to the total amount of the ink. Is even more preferable.
• the upper limit of the total content of the monofunctional monomer and the bifunctional monomer is not particularly limited, but is, for example, 80% by mass.
• the radically polymerizable monomer preferably contains a bifunctional monomer, and more preferably contains a monofunctional monomer and a bifunctional monomer.
• the ink contains a bifunctional monomer, silica particles are easily extruded onto the surface of the ink film during polymerization, so that the gloss of the obtained image is further suppressed.
• the content of the bifunctional monomer is preferably 5% by mass to 80% by mass, and preferably 10% by mass to 80% by mass, based on the total amount of the ink. More preferably, it is more preferably 20% by mass to 80% by mass.
• the mass ratio of the content of the bifunctional monomer to the content of the silica particles is preferably 1 to 100, more preferably 3 to 50. It is more preferably 4 to 20.
• the content of the radically polymerizable monomer is preferably 50% by mass or more, more preferably 60% by mass or more, and 65% by mass or more with respect to the total amount of the ink. It is more preferable that the amount is 70% by mass or more, and it is particularly preferable that the amount is 70% by mass or more.
• the upper limit of the content of the radically polymerizable monomer is not particularly limited, but is, for example, 80% by mass.
• monofunctional monomer examples include monofunctional (meth) acrylate, monofunctional (meth) acrylamide, monofunctional aromatic vinyl compound, monofunctional vinyl ether, and monofunctional N-vinyl compound.
• Examples of the monofunctional (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate.
• Tert-octyl (meth) acrylate isoamyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) Acrylate, 4-n-butylcyclohexyl (meth) acrylate, 4-tert-butylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, norbornyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, 2 -Ethylhexyl diglycol (meth) acrylate, butoxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 4-bromo
• Meta) acrylate EO-modified nonylphenol (meth) acrylate, propylene oxide-modified (hereinafter referred to as PO-modified) nonylphenol (meth) acrylate, EO-modified -2-ethylhexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclo Examples thereof include pentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (3-ethyl-3-oxetanylmethyl) (meth) acrylate, and phenoxyethylene glycol (meth) acrylate.
• Examples of the monofunctional (meth) acrylamide include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, and Nn-butyl (meth) acrylamide.
• Examples include (meth) acrylamide and (meth) acryloylmorpholin.
• Examples of the monofunctional aromatic vinyl compound include styrene, dimethylstyrene, trimethylstyrene, isopropylstyrene, chloromethylstyrene, methoxystyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, bromostyrene, vinyl benzoic acid methyl ester, and 3-methyl.
• Styrene 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene,3-octyl Styrene, 4-octyl styrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allyl styrene, isopropenyl styrene, butenyl styrene, octenyl styrene, 4-t-butoxycarbonyl styrene, and 4 -T-butoxystyrene can be mentioned.
• Examples of the monofunctional vinyl ether include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether and 4-methyl.
• Examples of the monofunctional N-vinyl compound include N-vinylcaprolactam, N-vinylpyrrolidone, N-vinyloxazolidinone, and N-vinyl-5-methyloxazolidinone.
• bifunctional monomer examples include a bifunctional (meth) acrylate, a bifunctional vinyl ether, and a bifunctional monomer containing a vinyl ether group and a (meth) acryloyl group.
• bifunctional (meth) acrylate examples include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and dipropylene glycol di (meth).
• bifunctional vinyl ether examples include 1,4-butanediol divinyl ether (ClogP value: 1.32), ethylene glycol divinyl ether (ClogP value: 0.66), and diethylene glycol divinyl ether (ClogP value: 0.47). Triethylene glycol divinyl ether (ClogP value: 0.29), polyethylene glycol divinyl ether (ClogP value: 0.29 or less), propylene glycol divinyl ether (ClogP value: 0.97), butylene glycol divinyl ether (ClogP value: 1).
• bifunctional monomer containing a vinyl ether group and a (meth) acryloyl group examples include 2- (2-vinyloxyethoxy) ethyl (meth) acrylate.
• trifunctional or higher functional monomer examples include trifunctional or higher functional (meth) acrylates and trifunctional or higher functional vinyl ethers.
• trifunctional or higher functional (meth) acrylate examples include trimethylolethanetri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, and PO-modified trimethylolpropane tri (meth) acrylate.
• trifunctional or higher functional vinyl ether examples include trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, trimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, and EO.
• Modified trimethylolpropane trivinyl ether PO-modified trimethylolpropane trivinyl ether, EO-modified dimethylolpropane tetravinyl ether, PO-modified dimethylolpropane tetravinyl ether, EO-modified pentaerythritol tetravinyl ether, PO-modified pentaerythritol tetravinyl ether, EO-modified dipentaerythritol Hexavinyl ether and PO-modified dipentaerythritol hexavinyl ether can be mentioned.
• urethane (meth) acrylate examples include urethane (meth) acrylate, which is a reaction product of a bifunctional isocyanate compound and a hydroxyl group-containing (meth) acrylate.
• bifunctional isocyanate compound examples include methylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dipropylether diisocyanate, 2,2-dimethylpentane diisocyanate, and 3-methoxyhexanediisocyanis.
• Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxy.
• Examples thereof include butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, phenylglycidyl ether (meth) acrylate, pentaerythritol (meth) triacrylate, and dipentaerythritol penta (meth) acrylate.
• Examples of the epoxy (meth) acrylate include a reaction product of (meth) acrylic acid and an epoxy resin.
• epoxy resin examples include bisphenol A type epoxy resin and cresol novolac type epoxy resin.
• the radically polymerizable monomer preferably contains a radically polymerizable monomer having a ClogP value of 2 or more.
• the ink contains two or more kinds of radically polymerizable monomers, it is preferable that at least one of the two or more kinds of radically polymerizable monomers is a radically polymerizable monomer having a LogP value of 2 or more.
• the ink contains a radically polymerizable monomer having a LogP value of 2 or more, hydrophobic interaction is likely to work with silica particles having a degree of hydrophobicity of 50 or more. As a result, the viscosity of the ink is lowered and the ejection property is improved.
• the mass ratio of the content of the radically polymerizable monomer having a ClogP value of 2 or more to the content of the silica particles is 5 to 100. It is preferably 6 to 50, more preferably 7 to 30, and even more preferably 7 to 30.
• Examples of the radically polymerizable monomer having a ClogP value of 2 or more include dipropylene glycol diacrylate (ClogP value: 2.04), tripropylene glycol diacrylate (ClogP value: 2.17), and phenoxyethyl acrylate (ClogP value: 2.04). 2.56), 3-methylpentanediol diacrylate (ClogP value: 2.89), isobornyl acrylate (ClogP value: 4.66), tricyclodecanedimethanol diacrylate (ClogP value: 4.66), Examples thereof include nonanediol diacrylate (ClogP value: 4.66) and lauryl acrylate (ClogP value: 6.62).
• the ClogP value is calculated using the fragment method.
• Examples of the calculation software using the fragment method include ChemDrawProfessional16.
• the radically polymerizable monomer preferably contains an N-vinyl compound.
• the N-vinyl compound has an action of pushing silica particles onto the surface of the ink film. Therefore, when the ink contains an N-vinyl compound, silica particles gather on the surface of the ink film, and the gloss of the obtained image is further suppressed.
• the mass ratio of the content of the N-vinyl compound to the content of the silica particles is preferably 1 to 15 and 1 to 15. It is more preferably 10 and even more preferably 1 to 8, and particularly preferably 1 to 7.
• the radically polymerizable monomer preferably contains a vinyl ether compound.
• the vinyl ether compound has a slow polymerization rate and is extruded together with the silica particles onto the surface of the ink film. Therefore, when the ink contains a vinyl ether compound, silica particles gather on the surface of the ink film, and the gloss of the obtained image is further suppressed.
• the vinyl ether compound is generally highly polar and aggregates silica particles, further suppressing the gloss of the obtained image.
• the polyfunctional vinyl ether compound has a high effect of pushing silica particles onto the surface of the ink film during polymerization. Therefore, the vinyl ether compound is preferably a polyfunctional vinyl ether compound. Further, from the viewpoint that the viscosity of the ink does not become too high and the ejection property is improved, the polyfunctional vinyl ether compound is preferably a bifunctional vinyl ether compound, and more preferably polyethylene glycol divinyl ether.
• the ClogP value of the vinyl ether compound is preferably less than 1.0, more preferably 0.5 or less.
• the ClogP value of the vinyl ether compound is less than 1.0, the effect of agglomerating the silica particles and suppressing the gloss of the image is high.
• the content of the vinyl ether compound is preferably 0.5% by mass to 10% by mass, more preferably 2% by mass to 8% by mass, based on the total amount of the ink.
• the ink of the present disclosure preferably contains at least one dispersant.
• the ink contains a dispersant, the dispersibility of the silica particles in the ink is improved. As a result, the ink ejection property is further improved.
• the type of dispersant is not particularly limited, but from the viewpoint of improving the dispersibility of silica particles having a degree of hydrophobicity of 50 or more, the dispersant is a polymer having a structural unit derived from a hydrophobic monomer having a ClogP value of 2 to 10. Is preferable.
• a polymer having a structural unit derived from a hydrophobic monomer having a ClogP value of 2 to 10 has a high adsorptivity to the surface of silica particles having a degree of hydrophobicity of 50 or more, so that the dispersibility of the silica particles is improved. As a result, the ink ejection property is further improved.
• Hydrophobic monomers having a ClogP value of 2 to 10 include, for example, styrene, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, and Examples include stearyl (meth) acrylate.
• the dispersant is preferably a basic dispersant.
• the basic groups contained in the dispersant are adsorbed on the silanol groups present on the surface of the silica particles, so that the dispersibility of the silica particles is improved. As a result, the ink ejection property is further improved.
• the dispersant may be a commercially available product.
• SOLSparse series manufactured by Noveon
• SOLSERSE 13940 17000, 20000, 24000, 26000, 28000, 32000, 35000, 36000, 39000, etc.
• BYK Chemie such as 2155, 2163, 2164, 9076, 9077, DISPERBYK-9076
• BYKJET series
• the mass ratio of the content of the dispersant to the content of the silica particles is preferably 0.05 to 0.5, preferably 0.08 to 0.2, from the viewpoint of stably dispersing the silica particles. More preferred.
• the ink of the present disclosure preferably contains at least one radical polymerization initiator.
• radical polymerization initiator examples include alkylphenone compounds, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketooxime ester compounds, borate compounds, azinium compounds, metallocene compounds, and activities.
• examples thereof include ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.
• the radical polymerization initiator is preferably an acylphosphine compound.
• acylphosphine oxide compound examples include a monoacylphosphine oxide compound and a bisacylphosphine oxide compound.
• Examples of the monoacylphosphine oxide compound include isobutyryldiphenylphosphine oxide, 2-ethylhexanoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and (2,4,6-trimethylbenzoyl) ethoxyphenyl.
• Phosphine oxide o-toluyldiphenylphosphine oxide, pt-butylbenzoyldiphenylphosphine oxide, 3-pyridylcarbonyldiphenylphosphine oxide, acryloyldiphenylphosphine oxide, benzoyldiphenylphosphine oxide, pivaloylphenylphosphine acid vinyl ester, adipoil bis Diphenylphosphine oxide, pivaloyldiphenylphosphine oxide, p-toluyldiphenylphosphine oxide, 4- (t-butyl) benzoyldiphenylphosphine oxide, terephthaloylbisdiphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, versatoyldiphenylphosphine Examples thereof include oxide, 2-methyl-2-ethylhexanoyldiphenylphosphine
• bisacylphosphine oxide compound examples include bis (2,6-dichlorobenzoyl) phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, and bis (2,6-dichlorobenzoyl).
• the acylphosphine oxide compounds are bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (product name "Omnirad 819", manufactured by IGM Resins VV), 2,4,6-trimethylbenzoyldiphenylphosphine.
• Oxide product name "Omnirad TPO H", manufactured by IGM Resins B.V.
• (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide product name "Omnirad TPO-L", IGM Resins B.V.
• the content of the radical polymerization initiator is preferably 1% by mass to 10% by mass, more preferably 2% by mass to 8% by mass, based on the total mass of the ink.
• the ink of the present disclosure may contain a sensitizer together with the radical polymerization initiator.
• the curability is improved, and particularly when an LED light source is used, the curability is improved.
• the sensitizer examples include polynuclear aromatic compounds, xanthene compounds, cyanine compounds, merocyanine compounds, thiazine compounds, aclysine compounds, anthraquinones (for example, anthraquinones), squalium compounds, coumarin compounds, and thioxanthones. Examples thereof include system compounds and thiochromanone compounds. Above all, the sensitizer is preferably a thioxanthone-based compound from the viewpoint of improving the image quality of the obtained image.
• thioxanthone compound examples include thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-dodecylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1 -Methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3- (2-methoxyethoxycarbonyl) thioxanthone, 4-butoxycarbonylthioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxy Carbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl-3-ethoxythioxanthone, 1-ethoxycarbonyl-3-a
• the thioxanthone-based compound is preferably 2,4-diethylthioxanthone, 2-isopropylthioxanthone, or 4-isopropylthioxanthone from the viewpoint of availability and improvement of image quality.
• the thioxanthone-based compound may be a commercially available product.
• commercially available products include SPEEDCURE series manufactured by Rambson (for example, SPEEDCURE 7010, SPEEDCURE CPTX, and SPEEDCURE ITX).
• the content of the sensitizer is preferably 1% by mass to 10% by mass, more preferably 1.5% by mass to 5% by mass, based on the total amount of the ink.
• the ink according to the present disclosure preferably contains at least one polymerization inhibitor.
• polymerization inhibitor examples include hydroquinone compounds, phenothiazines, catechols, alkylphenols, alkylbisphenols, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionic acid ester, and mercaptobenzimidazole. , Phosphites, nitrosoamine compounds, hinderedamine compounds, and nitroxyl radicals.
• the polymerization inhibitor is preferably at least one selected from the group consisting of a nitrosamine compound, a hindered amine compound, a hydroquinone compound, and a nitroxyl radical, and more preferably a nitrosamine compound.
• nitrosamine compound examples include N-nitroso-N-phenylhydroxylamine aluminum salt and N-nitroso-N-phenylhydroxylamine. Above all, the nitrosamine compound is preferably an N-nitrosamine-N-phenylhydroxylamine aluminum salt.
• the content of the polymerization inhibitor is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, based on the total amount of the ink, from the viewpoint of improving the stability of the ink over time.
• the upper limit of the content of the polymerization inhibitor is not particularly limited, but is preferably 1% by mass from the viewpoint of polymerizability.
• the ink of the present disclosure may contain at least one kind of coloring material.
• the type of coloring material is not particularly limited and may be either a pigment or a dye. From the viewpoint of light resistance, the coloring material is preferably a pigment.
• the pigment can be contained in the ink as a pigment dispersion liquid.
• the pigment dispersion liquid is a liquid obtained by dispersing a pigment in a liquid medium using a pigment dispersant, and contains at least a pigment, a pigment dispersant, and a liquid medium.
• pigment dispersant examples include the same dispersants as those described above (that is, dispersants for the purpose of dispersing silica particles).
• liquid medium examples include organic solvents. Further, the liquid medium may be the above-mentioned radically polymerizable monomer contained in the ink.
• the pigment may be either an organic pigment or an inorganic pigment that is usually commercially available. Further, the pigment may be an invisible pigment having infrared absorption.
• the content of the coloring material is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 10% by mass, based on the total amount of the ink. preferable.
• the ink of the present disclosure is a clear ink for recording a clear image
• the ink of the present disclosure does not have to contain substantially a coloring material.
• the content of the coloring material may be less than 1% by mass, less than 0.1% by mass, or 0% by mass with respect to the total amount of the ink.
• the clear image means an image having a transmittance of 80% or more at a wavelength of 400 nm to 700 nm.
• the ink of the present disclosure may contain other components other than the above components, if necessary.
• Other components include, for example, surfactants, co-sensitizers, UV absorbers, antioxidants, anti-fading agents, conductive salts, water, solvents, and basic compounds.
• the pH of the ink is preferably 7 to 10, and more preferably 7.5 to 9.5, from the viewpoint of improving the ejection property when the ink is applied by using an inkjet recording method.
• the pH is measured at 25 ° C. using a pH meter, and is measured, for example, using a pH meter (model number "HM-31") manufactured by Toa DKK Corporation.
• the viscosity of the ink is preferably 0.5 mPa ⁇ s to 30 mPa ⁇ s, more preferably 2 mPa ⁇ s to 20 mPa ⁇ s, preferably 2 mPa ⁇ s to 15 mPa ⁇ s, and 3 mPa ⁇ s. It is more preferably about 10 mPa ⁇ s.
• the viscosity is measured at 25 ° C. using a viscometer, and is measured, for example, using a TV-22 type viscometer manufactured by Toki Sangyo Co., Ltd.
• the surface tension of the ink is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 25 mN / m to 45 mN / m.
• the surface tension is measured at 25 ° C. using a surface tension meter, and is measured by a plate method using, for example, an automatic surface tension meter (product name “CBVP-Z”) manufactured by Kyowa Surface Science Co., Ltd.
• the image recording method of the present disclosure includes a step of applying the above ink on a recording medium by an inkjet recording method to obtain an ink film (hereinafter, also referred to as “first application step”), and an active energy ray on the ink film. It includes a step of irradiating (hereinafter, also referred to as “first irradiation step”).
• the image recording method of the present disclosure may include other steps, if necessary.
• the image recording method of the present disclosure uses the ink of the present disclosure. Therefore, according to the image recording method of the present disclosure, the same effect as that of the ink of the present disclosure is obtained.
• the first applying step is a step of applying the ink to the recording medium by an inkjet recording method to obtain an ink film.
• the type of recording medium is not particularly limited, and is, for example, paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal plate (for example, metal plate such as aluminum, zinc, copper, etc.), plastic.
• plastic for example, polyethylene, polypropylene, polystyrene, etc.
• metal plate for example, metal plate such as aluminum, zinc, copper, etc.
• Film for example, Polyvinyl Chloride (PVC) resin, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate (PET: Polyethylene Terephthalate), polyethylene (PE:: Polyethylene), polystyrene (PS: Polystyrene), polypropylene (PP: Polypropylene), polycarbonate (PC: Polycarbonate), polyvinyl acetal, acrylic resin and other films), paper on which the above-mentioned metals are laminated or vapor-deposited, and the above-mentioned. Examples include plastic films on which metal is laminated or vapor-deposited.
• PVC Polyvinyl Chloride
• the inkjet recording method is not particularly limited as long as it can record an image, and a known method can be used.
• Inkjet recording methods include, for example, a charge control method that uses electrostatic attraction to eject ink, a drop-on-demand method that uses the vibration pressure of a piezo element (pressure pulse method), and ink that converts electrical signals into acoustic beams.
• An acoustic inkjet method in which ink is ejected by irradiating the ink with radiation pressure, and a thermal inkjet (bubble jet (registered trademark)) method in which the ink is heated to form bubbles and the generated pressure is used. ..
• the inkjet head used in the inkjet recording method a short serial head is used, and a shuttle method in which recording is performed while scanning the head in the width direction of the base material and a recording element are arranged corresponding to the entire area of one side of the base material.
• a line method using a line head that has been used can be mentioned.
• a pattern can be formed on the entire surface of the base material by scanning the base material in a direction intersecting the arrangement direction of the recording elements, and a transport system such as a carriage that scans a short head becomes unnecessary. Further, in the line method, the movement of the carriage and the complicated scanning control with the base material are not required, and only the base material moves, so that the recording speed can be increased as compared with the shuttle method.
• the amount of ink ejected from the inkjet head is preferably 1 pL (picolitre) to 100 pL, more preferably 3 pL to 80 pL, and even more preferably 3 pL to 50 pL.
• First irradiation step the ink film obtained in the first application step is irradiated with active energy rays.
• the ink film is irradiated with active energy rays to polymerize at least a part of the radically polymerizable monomer in the ink film to obtain an image.
• the active energy ray is compared with the case where substantially all of the radically polymerizable monomer in the ink film is polymerized. Reduce the irradiation energy of.
• polymerizing only a part of the radically polymerizable monomer in the ink film is also referred to as “temporary curing”, and irradiation with active energy rays for temporary curing is also referred to as “pinning exposure”.
• polymerizing substantially all of the radically polymerizable monomers in the ink film is also referred to as “main curing”, and irradiation with active energy rays for main curing is also referred to as "main exposure”.
• the first irradiation step may be a step of applying pinning exposure (that is, temporary curing) to the ink film, or may be a step of applying main exposure (that is, main curing) to the ink film. death, It may be a step of applying the pinning exposure and the main exposure to the ink film in this order.
• the first irradiation step is a step of applying pinning exposure (that is, temporary curing) to the ink film
• an image of the temporarily cured ink film is obtained by the first irradiation step.
• the first irradiation step is a step of applying main exposure (that is, main curing) to the ink film, or a step of applying pinning exposure and main exposure to the ink film in this order
• the first irradiation step is performed. An image that is the main cured ink film can be obtained.
• the image recording method further includes a second applying step and a second irradiation step described later.
• the reaction rate of the ink film after pinning exposure is preferably 10% to 80%.
• reaction rate of the ink film means the polymerization rate of the radically polymerizable monomer in the ink film obtained by high performance liquid chromatography.
• the reaction rate of the ink film is 10% or more, insufficient spread of dots of the ink (for example, the second ink described later) applied on the ink film is suppressed.
• the graininess of the finally obtained image for example, a multi-order color image described later
• the graininess of the image is reduced.
• the reaction rate of the ink film is 80% or less, the spread of the ink applied on the ink film (for example, the second ink described later) is suppressed to be excessive, and the dots of the ink are suppressed. Drip interference between each other is suppressed. As a result, the image quality of the finally obtained image is improved.
• the reaction rate of the ink film is preferably 15% or more from the viewpoint of further improving the graininess of the finally obtained image.
• the reaction rate of the ink film is preferably 75% or less, more preferably 50% or less, still more preferably 40% or less, from the viewpoint of further improving the image quality of the finally obtained image. , 30% or less, and particularly preferably 25% or less.
• the reaction rate of the ink film after the main exposure is preferably more than 80% and 100% or less, more preferably 85% to 100%, and even more preferably 90% to 100%. When the reaction rate is more than 80%, the adhesion of the image is further improved.
• the reaction rate of the ink film is calculated using the following method.
• a recording medium that has been operated until the end of irradiation of the ink film on the recording medium with active energy rays, and prepare a sample piece having a size of 20 mm ⁇ 50 mm from the region where the ink film of the recording medium exists.
• a sample piece after irradiation is cut out, and the cut out sample piece after irradiation is immersed in 10 mL of THF (tetrahydrofuran) for 24 hours to obtain an eluate from which the ink is eluted.
• THF tetrahydrofuran
• the amount of radically polymerizable monomer hereinafter referred to as "amount of monomer after irradiation X1" is determined by high performance liquid chromatography.
• non-irradiated monomer amount X1 the amount of the radically polymerizable monomer
• Ink reaction rate (%) ((non-irradiated monomer amount X1-post-irradiated monomer amount X1) / unirradiated monomer amount X1) ⁇ 100
• the active energy ray in the irradiation step is preferably UV light (that is, ultraviolet light) in the wavelength range of 385 nm to 410 nm. It is more preferable that the UV light has the highest illuminance.
• the UV light source that is, the light source of UV light
• a known UV light source in which at least one of the illuminance and the irradiation time is variable can be used.
• the UV light source is preferably an LED (Light Emitting Diode) light source.
• Irradiation of the active energy ray in the irradiation step may be performed in an environment where the oxygen concentration is 20% by volume or less (more preferably less than 20% by volume, still more preferably 5% by volume or less). As a result, polymerization inhibition due to oxygen is suppressed, and an excellent image can be obtained due to the adhesion to the recording medium.
• an inert gas for example, nitrogen gas, argon gas, and helium gas
• nitrogen gas for example, nitrogen gas, argon gas, and helium gas
• the illuminance of the active energy ray for the pinning exposure is preferably 0.10 W / cm 2 to 0.50 W / cm 2 from the viewpoint of more easily achieving the reaction rate of the above-mentioned ink, and is more preferably 0.20 W / cm. It is more preferably cm 2 to 0.50 W / cm 2 , and even more preferably 0.20 W / cm 2 to 0.45 W / cm 2 .
• the irradiation energy of the active energy rays for pinning exposure may be 2 mJ / cm 2 to 20 mJ / cm 2 from the viewpoint of more easily achieving the above-mentioned ink reaction rate. It is preferably 4 mJ / cm 2 to 15 mJ / cm 2 , more preferably.
• the illuminance of the active energy ray for the main exposure is preferably 1.0 W / cm 2 or more, and 2.0 W / cm 2 or more, from the viewpoint of further improving the adhesion between the recording medium and the image. More preferably, it is more preferably 4.0 W / cm 2 or more.
• the upper limit of the illuminance of the active energy ray for the main exposure is not particularly limited, but is, for example, 10 W / cm 2 .
• the exposure amount of the active energy ray for the main exposure is preferably 20 mJ / cm 2 or more, and more preferably 80 mJ / cm 2 or more, from the viewpoint of further improving the adhesion between the recording medium and the image. preferable.
• the upper limit of the exposure amount of the active energy ray for the main exposure is not particularly limited, and is, for example, 240 mJ / cm 2 .
• a second ink is applied onto an ink film (hereinafter, also referred to as "first ink film”) irradiated with active energy rays in the first irradiation step, and the first ink film is coated with the second ink. It may include a second application step of obtaining a second ink film in contact with the ink film.
• the second ink is preferably an ink containing a radically polymerizable monomer and a radical polymerization initiator, and more preferably the ink of the present disclosure.
• the content of silica particles in the second ink is preferably higher than the content of silica particles in the first ink. Since the silica particles function as a surfactant, the higher the content of the silica particles, the lower the surface tension of the ink. That is, when the content of the silica particles contained in the second ink is larger than the content of the silica particles contained in the first ink, the surface tension of the second ink is lower than the surface tension of the first ink. As a result, when the second ink is applied onto the first ink film, the drip interference is suppressed. As a result, the image quality of the obtained image is improved.
• the ink of the present disclosure (hereinafter, also referred to as the first ink) applied in the first application step and the second ink have different hues.
• the second ink may be applied across the first ink film and the non-recording medium on which the first ink film is not formed.
• the second ink may be applied on at least a part of the first ink film, and does not necessarily have to be applied on the entire first ink film.
• the method of applying the second ink is the same as the method of applying the first ink, and the preferred embodiment is also the same.
• the image recording method of the present disclosure including the second application step may further include a second irradiation step of irradiating the entire first ink film and the second ink film with the second active energy ray. ..
• the second irradiation step may be a step of applying a pinning exposure to the entire first ink film and the second ink film, or a main exposure to the entire first ink film and the second ink film. It may be a step, or it may be a step of applying pinning exposure and main exposure to the entire first ink film and the second ink film in this order.
• the preferred embodiment of the second active energy ray and its irradiation conditions is the same as the preferred embodiment of the active energy ray and its irradiation conditions in the first irradiation step.
• the preferred irradiation conditions for the pinning exposure and the main exposure in the second irradiation step are the same as the preferable irradiation conditions for the pinning exposure and the main exposure in the first irradiation step.
• the content of the silica particles in the ink to be applied later is the content of the silica particles in the ink to be applied first from the viewpoint of improving the image quality of the obtained image.
• the content of the silica particles in the ink to be applied first is the content of the silica particles in the ink to be applied first from the viewpoint of improving the image quality of the obtained image.
• black ink, cyan ink, magenta ink, and yellow ink are applied, first, black ink is applied on the recording medium to obtain a black ink film, and then cyan is applied on the black ink film. It is preferable to apply ink, apply magenta ink on the cyan ink film, and apply yellow ink on the magenta ink film.
• the content of the silica particles contained in the cyan ink is higher than the content of the silica particles contained in the black ink.
• the content of silica particles contained in magenta ink is higher than the content of silica particles contained in cyan ink
• the content of silica particles contained in yellow ink is the content of silica particles contained in magenta ink.
• the content of silica particles means the content with respect to the total amount of each ink.
• Example 1 to Example 45 Comparative Example 1 to Comparative Example 10> First, a magenta pigment dispersion was prepared.
• magenta pigment dispersion 30 parts by mass of magenta pigment, 50 parts by mass of "SR341", and 20 parts by mass of "SOLSPERSE 32000" were put into a disperser motor mill M50 (manufactured by Eiger), and a peripheral speed was used using zirconia beads having a diameter of 0.65 mm. The dispersion treatment was carried out at 9 m / s for 8 hours to obtain a magenta pigment dispersion.
• each component contains the prepared magenta pigment dispersion and the silica particles, radically polymerizable monomers, radical polymerization initiators, sensitizers, polymerization inhibitors, and dispersants shown in Tables 2 to 7 below.
• the mixture was mixed so as to have the content (% by mass) shown in Tables 2 to 7.
• the mixture was stirred for 20 minutes at 25 ° C. under the condition of 5000 rpm using a mixer (product name “L4R”, manufactured by Silberson) to obtain ink.
• the unit of the average primary particle size and the average secondary particle size of the silica particles is "nm", and the unit of the surface area is "m 2 / g".
• “Monomer / silica particles having a ClogP value of 2 or more” means the mass ratio of the content of the radically polymerizable monomer having a ClogP value of 2 or more to the content of the silica particles.
• “N-vinyl compound / silica particles” means the mass ratio of the content of the N-vinyl compound to the content of the silica particles.
• FLORSTAB UV-12 (manufactured by Kromachem) was used for the preparation of the ink.
• FLORSTAB UV12 is a mixture of N-nitroso-N-phenylhydroxylamine aluminum salt and PEA, and the mixing ratio is 1: 9. Since the N-nitroso-N-phenylhydroxylamine aluminum salt is a polymerization inhibitor and PEA is a radically polymerizable monomer, the polymerization inhibitor and the radically polymerizable monomer will be described below separately. For example, when the content of FLORSTAB UV-12 contained in the ink was 0.5% by mass, PEA was 0.45% by mass and N-nitroso-N-phenylhydroxylamine aluminum salt was 0.05% by mass.
• ⁇ Radical polymerizable monomer (referred to as "polymerizable monomer” in the table)> -4-HBA: 4-Hydroxybutyl acrylate (product name "4-HBA", manufactured by Osaka Organic Chemical Industry Co., Ltd.) -VMOX: 5-Methyl-3-vinyloxazolidine-2-one (product name "VMOX”, manufactured by BASF) -TEGDA: Triethylene glycol diacrylate (product name "SR268", manufactured by Sartomer) -NVC: N-vinylcaprolactam (product name "NVC", manufactured by BASF) -OXEA: (3-ethyloxetane-3-yl) methyl acrylate (product name "Oxe-10", manufactured by Osaka Organic Chemical Co., Ltd.) -GTA: Glycerin triacrylate (product name "Aronix M930", manufactured by Sartomer) -DPGDA: Dipropylene glycol diacrylate (product
• ⁇ Radical polymerization initiator (referred to as "polymerization initiator" in the table)>
• Ominirad 819 Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (manufactured by IGM Resins B.V.)
• TPO-L (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide (product name "Omnirad TPO-L", manufactured by IGM Resins BV)
• An image recording device (specifically, an inkjet recording device) including a UV light source, a head for yellow ink, a UV light source, a head for white ink, and a nitrogen purge UV exposure machine was prepared.
• the transport system was a single-pass type sheet-fed printing press.
• the black ink head, cyan ink head, magenta ink head, and yellow ink head are each equipped with an inkjet nozzle (hereinafter, also simply referred to as “nozzle”) as a piezo type inkjet head (specifically, a line head). ). From each nozzle, 1 pL to 60 pL multi-size dots can be ejected at a resolution of 1,200 ⁇ 1,200 dpi. Here, dpi represents the number of dots per 2.54 cm.
• the ink supply system of this inkjet recording device is composed of a former tank, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and an inkjet head.
• the portion of the ink supply system from the ink supply tank to the inkjet head was heat-insulated and heated. Further, temperature sensors were provided near the nozzles of the ink supply tank and the inkjet head, respectively, and the temperature was controlled so that the nozzle portion was always 70 ° C. ⁇ 2 ° C.
• the original tank connected to the magenta ink head contained one of the inks for each embodiment and the inks for each comparative example.
• an LED (Light Emitting Diode) lamp manufactured by Kyocera capable of irradiating UV light having the highest illuminance in the wavelength range of 385 nm to 410 nm, respectively. 4 cm width, G4B, maximum illuminance 10 W) was used.
• Each of these UV light sources is a UV light source whose illuminance and irradiation time of UV light can be changed.
• the recording medium is so that the irradiation of UV light to the landed ink is started 0.1 seconds after the ink ejected from each head lands on the recording medium. The transport speed was adjusted.
• the pinning exposure was carried out in an atmosphere (oxygen concentration 20%) with a UV light source immediately after the magenta ink head.
• This exposure was carried out by a nitrogen purge UV exposure machine in an atmosphere with an oxygen concentration of 1% and a nitrogen concentration of 99%.
• the obtained image recording material was used to suppress the gloss of the image and the image quality was evaluated, and the ink was used to evaluate the ejection property.
• the evaluation method is as follows. The evaluation results are shown in Tables 2 to 7.
• the gloss difference [image-recording medium] was less than 20.
• the gloss difference [image-recording medium] was 20 or more and less than 25.
• the gloss difference [image-recording medium] was 25 or more and less than 30.
• the gloss difference [image-recorded medium] was 30 or more and less than 40.
• the gloss difference [image-recorded medium] was 40 or more.
• image quality The obtained image recording material was visually observed, and the image quality (specifically, graininess) of the image was evaluated.
• the evaluation criteria are as follows. The rank with the best graininess is "5". 5: No roughness was observed in the entire image and the image was uniform. 4: There was a slight graininess in the image, but it was almost uniform as a whole. 3: There is a slight graininess in the image, but it was at a level that was not a problem in practical use. 2: The image was rough and conspicuous even visually, which was a problem in practical use. 1: The image had a lot of roughness with strong shading, and it was a level that could not be said to be uniform.
• the inks of Examples 1 to 45 contain a radically polymerizable monomer and silica particles, and the silica particles have an average primary particle size of 22 nm or more and less than 100 nm, and the silica particles have an average primary particle size of 22 nm or more and less than 100 nm. It was possible to record an image having a degree of hydrophobicity of 50 or more, excellent ejection properties, and suppressed gloss.
• Comparative Example 1 it was found that the average primary particle size of the silica particles was as small as 18 nm, so that the ink ejection property was inferior.
• Comparative Example 2 Comparative Example 6, and Comparative Example 7, it was found that since the degree of hydrophobicity of the silica particles was 0, an image in which the ink ejection property was inferior and the gloss was suppressed could not be obtained.
• Comparative Example 9 and Comparative Example 10 it was found that the average primary particle size of the silica particles was as large as 400 nm and 500 nm, respectively, and therefore the ink ejection property was inferior.
• Example 26 the average secondary particle size of the silica particles was 200 nm to 800 nm, and an image with more suppressed gloss was obtained as compared with Example 42.
• Example 26 the product of the average primary particle size of the silica particles and the specific surface area was 2400 or less, and it was found that an image with more suppressed gloss was obtained as compared with Example 42.
• Example 4 since the content of the silica particles is 1% by mass to 10% by mass, the graininess is excellent and the gloss is higher than that of Example 1 in which the content of the silica particles is less than 1% by mass. It was found that a more suppressed image was obtained.
• Example 4 since the content of the silica particles is 1% by mass to 10% by mass, the ink ejection property is excellent as compared with Example 7 in which the content of the silica particles is more than 10% by mass. It was found that an image with less gloss was obtained.
• Example 12 since the mass ratio of the content of the radically polymerizable monomer having a ClogP value of 2 or more to the content of the silica particles is 6 to 50, the mass ratio is less than 6, as compared with Example 11. It was found that an image having excellent ink ejection properties and less gloss was obtained.
• Example 4 since the mass ratio of the content of the radically polymerizable monomer having a ClogP value of 2 or more to the content of the silica particles is 6 to 50, the mass ratio is more than 50, as compared with Example 2. It was found that an image having excellent graininess and less gloss was obtained.
• Example 13 since the ink contains the N-vinyl compound, the graininess is excellent and the gloss is further suppressed as compared with Example 17 in which the ink does not contain the N-vinyl compound. It turned out that an image was obtained.
• Example 19 since the mass ratio of the content of the N-vinyl compound to the content of the silica particles is 1 to 8, the graininess is excellent as compared with Example 21 in which the mass ratio is more than 8. It was found that an image with less gloss was obtained.
• Example 4 since the mass ratio of the content of the N-vinyl compound to the content of the silica particles is 1 to 8, the ink ejection property is excellent as compared with Example 7 in which the mass ratio is less than 1. Moreover, it was found that an image with more suppressed gloss can be obtained.
• Example 45 since the ink contained a vinyl ether compound, it was found that an image having more suppressed gloss was obtained as compared with Example 23, which did not contain the vinyl ether compound.
• Example 46 to 53 In addition to the magenta pigment dispersion, a cyan pigment dispersion, a yellow pigment dispersion, and a black pigment dispersion were prepared for recording a multi-order color image.
• the cyan pigment dispersion, the yellow pigment dispersion, and the black pigment dispersion were prepared by the same method as the magenta pigment dispersion by changing the magenta pigment to a cyan pigment, a yellow pigment, and a black pigment, respectively.
• each component of each of the prepared pigment dispersions and the silica particles, radically polymerizable monomers, radical polymerization initiators, sensitizers, polymerization inhibitors, and dispersants shown in Table 8 below is shown in Table 8.
• the mixture was mixed so as to have the stated content (% by mass).
• the mixture was stirred for 20 minutes at 25 ° C. under the condition of 5000 rpm using a mixer (product name “L4R”, manufactured by Silberson) to obtain ink.
• Example 46 An image recording device was prepared in the same manner as in Example 1.
• Example 46 The ink of Example 46 is stored in the original tank connected to the black ink head, the ink of Example 47 is stored in the original tank connected to the cyan ink head, and the original tank connected to the magenta ink head is used. Forty-eight inks were stored, and the ink of Example 49 was stored in the original tank connected to the yellow ink head.
• each original tank is washed, the ink of Example 50 is stored in the original tank connected to the black ink head, and the ink of Example 51 is stored in the original tank connected to the cyan ink head.
• the original tank connected to the magenta ink head contained the ink of Example 52, and the original tank connected to the yellow ink head contained the ink of Example 53.
• Example 46 using the above-mentioned image recording apparatus, the ink (black ink) of Example 46 is applied to the recording medium in a solid shape so that the halftone dot area ratio is 100%, and the black ink is applied.
• the ink is irradiated with UV light at an illuminance of 0.40 W / cm 2 for 0.024 seconds (pinning exposure), and then irradiated with UV light at an illuminance of 5.0 W / cm 2 for 0.024 seconds (main exposure). ), An image recording material in which an image (specifically, a solid image) was recorded was obtained.
• the pinning exposure was carried out in an atmosphere (oxygen concentration 20%) with a UV light source immediately after the black ink head.
• This exposure was carried out by a nitrogen purge UV exposure machine in an atmosphere with an oxygen concentration of 1% and a nitrogen concentration of 99%.
• Example 47 using the above-mentioned image recording apparatus, the ink (black ink) of Example 46 is applied to the recording medium in a solid shape so that the halftone dot area ratio is 100%, and the black ink is applied.
• the ink was irradiated with UV light for 0.024 seconds at an illuminance of 0.40 W / cm 2 (pinning exposure).
• the ink (cyan ink) of Example 47 was applied solidly on the semi-cured black ink film so that the halftone dot area ratio was 100%, and 0.40 W / cm 2 was applied to the applied cyan ink.
• UV light was irradiated for 0.024 seconds at the illuminance of. (Pinning exposure). Then, by irradiating (main exposure) with UV light for 0.024 seconds at an illuminance of 5.0 W / cm 2 , an image recording material in which an image (specifically, a solid image) was recorded was obtained.
• the pinning exposure was carried out in an atmosphere (oxygen concentration 20%) by a UV light source immediately after the black ink head and the cyan ink head.
• This exposure was carried out by a nitrogen purge UV exposure machine in an atmosphere with an oxygen concentration of 1% and a nitrogen concentration of 99%.
• Example 48 using the above-mentioned image recording apparatus, the ink (black ink) of Example 46 is applied to the recording medium in a solid shape so as to have a halftone dot area ratio of 100%, and the black ink is applied.
• the ink was irradiated with UV light for 0.024 seconds at an illuminance of 0.40 W / cm 2 . (Pinning exposure).
• the ink (cyan ink) of Example 47 was applied solidly on the semi-cured black ink film so that the halftone dot area ratio was 100%, and 0.40 W / cm 2 was applied to the applied cyan ink. UV light was irradiated for 0.024 seconds at the illuminance of (pinning exposure).
• Example 48 The ink of Example 48 (magenta ink) was applied solidly on the semi-cured cyan ink film so that the halftone dot area ratio was 100%, and 0.40 W / cm 2 was applied to the applied magenta ink.
• UV light was irradiated for 0.024 seconds at the illuminance of (pinning exposure). Then, by irradiating (main exposure) with UV light for 0.024 seconds at an illuminance of 5.0 W / cm 2 , an image recording material in which an image (specifically, a solid image) was recorded was obtained.
• the pinning exposure was carried out in an atmosphere (oxygen concentration 20%) by a UV light source immediately after the black ink head, the cyan ink head, and the magenta ink head.
• This exposure was carried out by a nitrogen purge UV exposure machine in an atmosphere with an oxygen concentration of 1% and a nitrogen concentration of 99%.
• Example 49 using the above-mentioned image recording apparatus, the ink (black ink) of Example 46 is applied to the recording medium in a solid shape so as to have a halftone dot area ratio of 100%, and the black ink is applied.
• the ink was irradiated with UV light for 0.024 seconds at an illuminance of 0.40 W / cm 2 . (Pinning exposure).
• the ink (cyan ink) of Example 47 was applied solidly on the semi-cured black ink film so that the halftone dot area ratio was 100%, and 0.40 W / cm 2 was applied to the applied cyan ink. UV light was irradiated for 0.024 seconds at the illuminance of (pinning exposure).
• Example 48 magenta ink
• Example 49 yellow ink
• UV light was irradiated for 0.024 seconds at the illuminance of (pinning exposure).
• main exposure by irradiating (main exposure) with UV light for 0.024 seconds at an illuminance of 5.0 W / cm 2 , an image recording material in which an image (specifically, a solid image) was recorded was obtained.
• the pinning exposure was carried out in an atmosphere (oxygen concentration 20%) by a UV light source immediately after the black ink head, the cyan ink head, the magenta ink head, and the yellow ink head.
• This exposure was carried out by a nitrogen purge UV exposure machine in an atmosphere with an oxygen concentration of 1% and a nitrogen concentration of 99%.
• Example 46 gloss suppression and image quality evaluation were performed on the black image recorded on the recording medium using the ink of Example 46.
• gloss suppression and image quality evaluation were performed on the cyan image recorded on the black image using the ink of Example 47.
• Example 48 gloss suppression and image quality evaluation were performed on the magenta image recorded on the cyan image using the ink of Example 48.
• Example 49 gloss suppression and image quality evaluation were performed on the yellow image recorded on the magenta image using the ink of Example 49.
• Examples 50 to 53 gloss suppression and image quality evaluation were performed in the same manner as in Examples 46 to 49.
• the evaluation method is the same as the evaluation for Example 1. The evaluation results are shown in Table 8.
• Each ink tank provided in an inkjet recording device (product name "Jet Press 540WV”, manufactured by FUJIFILM Corporation) was individually filled with ink of each color.
• an undercoat composition UV curable ink (product name “Uvijet MK702”, manufactured by FUJIFILM Corporation) and UV curable ink (product name “Uvijet MK703", manufactured by FUJIFILM Corporation) were mixed at a mass ratio of 85:15. A mixed solution was used. Further, as the white ink, a UV curable ink (product name "Uvijet MK021", manufactured by FUJIFILM Corporation) was used.
• UV curable ink (product name "Uvijet MKA04", manufactured by FUJIFILM Corporation) was used.
• cyan ink a UV curable ink (product name "Uvijet MK215", manufactured by FUJIFILM Corporation) was used.
• magenta ink UV curable ink (product name "Uvijet MK867”, manufactured by FUJIFILM Corporation) was used.
• yellow ink UV curable ink (product name "Uvijet MKA52”, manufactured by FUJIFILM Corporation) was used.
• a biaxially stretched polyester film (product name "Emblet PTM-12”, manufactured by Unitika Ltd., film thickness 12 ⁇ m) was used.
• the undercoat composition was applied onto the recording medium. After applying the undercoat composition, pinning exposure was performed at an illuminance of 750 mW / cm 2 to form an undercoat layer. Next, a solid image was recorded with white ink on the obtained undercoat layer, and black ink, cyan ink, magenta ink, and yellow ink were ejected on the obtained solid image in this order. Even after each ink was ejected, pinning exposure was performed at an illuminance of 750 mW / cm 2 in the same manner as after the undercoat composition was applied.
• the main exposure was performed from the upper part of the recording medium (that is, the side where the image is recorded) under a nitrogen atmosphere having an oxygen concentration of less than 0.1% by volume at an illuminance of 3000 mW / cm 2 . ..
• the nitrogen purge was performed using the nitrogen generator attached to the inkjet recording device.
• the main exposure was performed from the lower part of the recording medium (that is, the side on which the image was not recorded) at an illuminance of 3000 mW / cm 2 to obtain an image recorded object.
• the transport speed of the recording medium was set to 50 m / min.
• ⁇ Reference example 3> Add 0.8 g of a silicon-based surfactant (product name "BYK-307", manufactured by BYK) to 1 liter of UV curable ink (product name "Uvijet MK021", manufactured by Fujifilm) and stir well. As a result, white ink was prepared. An image recording was obtained by the same method as in Reference Example 2 except that the prepared white ink was used instead of the UV curable ink (product name "Uvijet MK021", manufactured by FUJIFILM Corporation).

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