JP2019116072A - Gravure printing method - Google Patents

Abstract

To provide a gravure printing method which improves ink transferability of aqueous ink, and can suppress plate fogging.SOLUTION: A gravure printing method that stores aqueous ink in an ink pan and performs printing by a furnisher roll and a gravure roll, in which the aqueous ink contains a pigment, a polymer, an organic solvent, a surface active agent and water, a content of the organic solvent having a boiling point of lower than 100°C is 5 mass% or less in the aqueous ink, a static surface tension at 20°C of the aqueous ink is 23 mN/m or more and 30 mN/m or less, rubber hardness of the furnisher roll is 55° or more and 85° or less, a contact pressure of the furnisher roll contacting the gravure roll is 0.08 MPa or more and 0.4 Mpa or less, and the number of revolution of the furnisher roll is 4% or more and 28% or less with respect to 100% of the number of revolution of the gravure roll.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gravure printing method.

Gravure printing is a printing method in which ink is transferred to a printing substrate using a gravure plate on which cells for receiving ink are formed. The quality of printing can be controlled by the depth of cells and the spacing (number of lines) of cells, and is widely used because high-definition printing can be performed.
Conventionally, oil-based inks have been used in gravure printing, but there are problems with the working environment, global environment, disaster prevention, and residual solvents when used for food-related matters. Further, in gravure printing, the use amount of oil-based ink is large, and there is a problem that it is difficult to meet the market needs of recent wide variety and small-lot production.
From the above reasons, a gravure printing method using an aqueous ink has attracted attention. However, in the case of water-based ink, the same method as oil-based ink not only causes a decrease in printing speed but also problems of ink transferability and plate fog due to poor drying and poor ink wetting to the plate surface due to surface tension. The problem is that high quality printed matter can not be obtained.

Then, various proposals are made regarding the gravure printing method.
For example, Patent Document 1 discloses an ink supply method of supplying ink subjected to dispersion processing by ultrasonic waves to a gravure plate by a finisher roll.
In Patent Document 2, in a gravure printing press having a finisher roll disposed on the opposite side of a doctor knife, an ink leveling roll is disposed between the ink pan and the doctor knife on the doctor knife side, and A gravure printing press in which the circumferential speed of the finisher roll is set to 5 to 50% of the circumferential speed of the plate cylinder, and the circumferential speed of the ink leveling roll is set to 5 to 120% of the circumferential velocity of the plate cylinder It is disclosed.
Patent Document 3 discloses, as a resin composition for aqueous ink that can be developed into gravure printing, an ethylenically unsaturated monomer (B) in an aqueous medium, using a water-soluble resin (A) having a carboxyl group as a polymeric emulsifier. A resin for an aqueous ink comprising: a core-shell type resin fine particle dispersion (C) obtained by emulsion polymerization of (A), a carbodiimide group-containing resin fine particle dispersion (D), and a water-insoluble epoxy group containing compound (E) A composition is disclosed.

Japanese Patent Application Laid-Open No. 62-134264 JP, 2010-260194, A JP, 2016-060885, A

However, the techniques of Patent Documents 1 to 3 can not satisfy the demand for improvement of ink transferability and suppression of plate fogging in gravure printing using aqueous ink.
An object of the present invention is to provide a gravure printing method capable of improving the ink transferability of water-based ink and suppressing plate fog.

The present inventors have found that the above problems can be solved by adjusting the relationship between the composition and physical properties of the water-based ink, the rubber hardness of the finisher roll and the operating conditions, and adjusting them.
That is, the present invention is a gravure printing method of storing aqueous ink in an ink pan and printing using a finisher roll and a gravure roll,
The aqueous ink comprises a pigment, a polymer, an organic solvent, a surfactant and water.
The content of the organic solvent having a boiling point of less than 100 ° C. in the aqueous ink is 5% by mass or less,
The static surface tension at 20 ° C. of the water-based ink is from 23 mN / m to 30 mN / m,
The rubber hardness of the finisher roll is 55 ° or more and 85 ° or less,
The contact pressure with which the finisher roll contacts the gravure roll is 0.08 MPa or more and 0.4 MPa or less,
The gravure printing method is provided, wherein the number of revolutions of the finisher roll is 4% or more and 28% or less with respect to 100% of the number of revolutions of the gravure roll.

  ADVANTAGE OF THE INVENTION According to this invention, the gravure printing method which can improve the ink transfer property of water-based ink and can suppress plate fog can be provided.

It is a cross-sectional schematic diagram which shows one Embodiment of the gravure printer used by this invention method.

[Gravure printing method]
The gravure printing method of the present invention is a gravure printing method in which an aqueous ink is stored in an ink pan and printed using a finisher roll and a gravure roll, wherein the aqueous ink comprises a pigment, a polymer, an organic solvent, and a surfactant. Agent and water, wherein the content of the organic solvent having a boiling point of less than 100 ° C. in the aqueous ink is 5% by mass or less, and the static surface tension at 20 ° C. of the aqueous ink is 23 mN / m to 30 mN / m The contact pressure with which the finisher roll contacts the gravure roll is 0.08 MPa or more and 0.4 MPa or less; The rotation speed of the shear roll is characterized by being 4% or more and 28% or less with respect to 100% of the rotation speed of the gravure roll.

Gravure printing method
In gravure printing, ink is supplied to the plate surface of a gravure roll while rotating a gravure roll (gravure plate) having concave cells formed on the surface, and the doctor blade fixed at a predetermined position scrapes the ink only in the cell Leaving the ink, press the printing substrate supplied continuously to the gravure roll with a nip roll whose surface is formed of rubber, and transfer only the ink in the cells of the gravure roll to the printing substrate, to print characters and It is a method of printing an image.
FIG. 1 is a schematic cross-sectional view showing an embodiment of a gravure printing press used in the method of the present invention. The gravure printing method by this gravure printer 1 is demonstrated.
As shown in FIG. 1, the gravure printing press 1 includes an ink pan 10, a finisher roll 11, a gravure roll 12, a doctor blade 13, and a nip roll 14. In the gravure printing press 1, the finisher roll 11, the gravure roll 12 and the nip roll 14 are continuously rotated in the arrow direction of FIG. 1.
The gravure printer 1 performs printing on a printing substrate 20 which is continuously transported. The gravure printing machine 1 further includes a printing substrate supply roll 15 for feeding the printing substrate 20 to which printing is to be performed, and a printing substrate winding roll 16 for winding the printed printing substrate 20.

The ink pan 10 stores water-based ink used for printing on the printing substrate 20. The aqueous ink contains a pigment, a polymer, an organic solvent, a surfactant, and water, and the content of the organic solvent having a boiling point of less than 100 ° C. in the aqueous ink is 5% by mass or less, and the static of the aqueous ink at 20 ° C. The surface tension is 23 mN / m or more and 30 mN / m or less.
The finisher roll 11 is provided so that the outer peripheral surface thereof is immersed in the water-based ink in the ink pan 10. By rotating the finisher roll 11 in the direction of the arrow in FIG. 1, the water-based ink in the ink pan 10 adheres to the outer peripheral surface of the finisher roll 11.

The gravure roll 12 is installed at a position in contact with the finisher roll 11. A plurality of cells (recesses) are provided on the surface of the gravure roll 12, and the aqueous ink attached to the outer surface of the finisher roll 11 by rotating while the finisher roll 11 abuts on the gravure roll 12. Is transferred into each cell (recess) of the gravure roll 12 and filled in each cell.
The rubber hardness of the finisher roll 11 is 55 ° or more and 85 ° or less, and the contact pressure with which the finisher roll 11 contacts the gravure roll 12 is 0.08 MPa or more and 0.4 MPa or less. The rotation speed of is 4% or more and 28% or less with respect to 100% of the rotation speed of the gravure roll.
The water-based ink is preferably filled only in each cell of the gravure roll 12, but among the inks sent from the outer surface of the finisher roll 11 to the gravure roll 12, excess ink not filled in each cell is also used. Occur.

The doctor blade 13 is on the downstream side of the contact point between the finisher roll 11 and the gravure roll 12 in the rotational direction of the gravure roll 12 (the direction of the arrow in FIG. 1). It is installed on the upstream side of the place.
The doctor blade 13 rubs against the outer surface of the gravure roll 12 to maintain the aqueous ink filled in each cell of the gravure roll 12 as it is, and the gravure roll is not filled in each cell. Scrape off the excess ink on the surface of the 12 convexes. At this time, the aqueous ink filled in each cell (recess) of the gravure roll 12 is not scraped off by the doctor blade 13.

The nip roll 14 is in contact with the gravure roll 12 via the printing base 20 on the downstream side of the contact point with the doctor blade 13 in the rotational direction of the gravure roll 12. The nip roll 14 interposes the printing base 20 with the gravure roll 12, whereby the water base ink in each cell of the gravure roll 12 is applied to the printing base 20 continuously fed from the printing base supply roll 15. Transfer and print.
The printing substrate 20 on which the aqueous ink is transferred and printed is dried by a drying device (not shown). The dried printing substrate 20 is taken up by the printing substrate winding roll 16. In this way, a roll of the printing substrate 20 subjected to gravure printing is obtained.

The gravure printing press 1 and the gravure printing method are not limited to the above embodiment, and various modifications can be made.
For example, in the case of performing multicolor gravure printing, an embodiment in which a plurality of printing units including an ink pan 10 for storing ink of each color, a finisher roll 11, a gravure roll 12, a doctor blade 13 and a nip roll 14 are provided in series. It can be done.

<Fnisher roll>
In the gravure printing method of the present invention, the finisher roll 11 having a rubber hardness of 55 ° or more and 85 ° or less is used. Here, the rubber hardness is a value measured by a rubber hardness tester according to a method defined by JIS K 6301-1975 and JIS K 7125-1986.
The rubber hardness is preferably 58 ° or more, more preferably 60 ° or more, more preferably 62 ° or more, and preferably 83 ° from the viewpoint of improving the ink transferability of the water-based ink and suppressing the plate fog. More preferably, it is 82 degrees or less, More preferably, it is 80 degrees or less.
Materials used for the finisher roll 11 include isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene rubber (EPDM / EPM), butyl rubber ( IIR), silicone rubber, chloropyrene rubber (CR), chlorosulfonated polyethylene rubber, acrylic rubber, hydrin rubber, urethane rubber, polysulfide rubber (thiocol), fluororubber and the like.
Among these, from the viewpoint of improving the ink transferability of the aqueous ink and suppressing the plate fog, it is preferably selected from acrylonitrile-butadiene rubber (NBR), ethylene propylene rubber (EPDM / EPM), and butyl rubber (IIR) One or more.
The thickness of the rubber of the finisher roll 11 is preferably 2 mm or more, more preferably 3 mm or more, still more preferably 5 mm or more, and preferably 30 mm or less, more preferably 25 mm or less, further preferably 20 mm or less .

The contact pressure with which the finisher roll 11 contacts the gravure roll 12 is 0.08 MPa or more and 0.4 MPa or less from the viewpoint of appropriately supplying water-based ink, improving ink transferability, and suppressing plate fog. The contact pressure is preferably 0.1 MPa or more, more preferably 0.15 MPa or more, further preferably 0.2 MPa or more, and preferably 0.48 MPa or less, more preferably 0.46 MPa or less, still more preferably It is 0.4 MPa or less.
The rotation speed of the finisher roll 11 is 4% or more to 28% of the rotation speed 100% of the gravure roll 12 from the viewpoint of appropriately supplying water-based ink, improving ink transferability, and suppressing plate fog. It is below. The number of rotations is preferably 5% or more, more preferably 8% or more, further preferably 10% or more, and preferably 25% or less, more preferably 23% or less, still more preferably 20% or less. .

<Printing substrate>
Examples of printing substrates used in the gravure printing method include coated paper, art paper, synthetic paper, paper such as processed paper, polyester film, polyethylene film, polypropylene film, polypropylene film, polystyrene film, vinyl chloride film, resin film such as nylon film, etc. It can be mentioned. The printing substrate is preferably a resin film from the viewpoint of versatility, and more preferably a polyester film, a uniaxially stretched film, a biaxially stretched polypropylene film or the like from the viewpoint of post-processing aptitude such as punching after producing a printed material.
Further, from the viewpoint of improving the gravure printing suitability, a resin film obtained by surface treating the above-mentioned polyester film, uniaxially stretched or biaxially stretched polypropylene film, etc. by electrical discharge processing such as corona discharge treatment or plasma discharge treatment is more preferable. .
The thickness of the printing substrate is usually 10 μm or more and 100 μm or less.

<Water-based ink>
The aqueous ink (hereinafter also referred to as "ink") used in the present invention contains a pigment, a polymer, an organic solvent, a surfactant, and water.
Here, "aqueous ink" means an ink or an aqueous solution or dispersion in which water or a mixture of water and an organic solvent is used as a diluent.
Hereinafter, each component contained in the water-based ink will be described.

<Pigment>
The pigment used in the aqueous ink may be either an inorganic pigment or an organic pigment.
As an inorganic pigment, carbon black, a metal oxide, etc. are mentioned, for example, and in black ink, carbon black is preferable. As carbon black, furnace black, thermal lamp black, acetylene black, channel black etc. are mentioned. Examples of white ink include titanium dioxide, zinc oxide, silica, alumina, metal oxides such as magnesium oxide, and the like. These inorganic pigments may be surface-treated with known hydrophobicizing agents such as titanium coupling agents, silane coupling agents, and higher fatty acid metal salts.
Examples of the organic pigment 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 in the case of a chromatic color ink, any of chromatic color pigments such as yellow, magenta, cyan, red, blue, orange and green can be used.

The form of the pigment is preferably at least one selected from self-dispersible pigments and pigment particles dispersed with a polymer, and more preferably pigment particles dispersed with a polymer (hereinafter also referred to as "pigment particles A") is there.
A self-dispersible pigment can be dispersed in an aqueous medium without using a surfactant or a resin by bonding one or more of hydrophilic functional groups directly to the surface of the pigment or through other atomic groups. It means a certain pigment. In order to make the pigment a self-dispersible pigment, for example, the necessary amount of hydrophilic functional group may be chemically bonded to the pigment surface by a conventional method.
The content of the pigment in the ink is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more from the viewpoint of printing density, and preferably 30% by mass or less, more preferably Preferably it is 25 mass% or less, More preferably, it is 20 mass% or less.

<Polymer>
The polymer used for the aqueous ink may be a water soluble polymer or a water insoluble polymer, but a water insoluble polymer is more preferable.
A water-soluble polymer is a polymer which is dried at 105 ° C. for 2 hours and the constant weight of the polymer is dissolved in 100 g of water at 25 ° C., and the dissolved amount is 10 g or more. And a polymer whose dissolved amount is less than 10 g.
Examples of the polymer to be used include polyesters, polyurethanes, vinyl polymers and the like, and from the viewpoint of dispersion stability of the pigment, vinyl polymers obtained by addition polymerization of vinyl monomers such as vinyl compounds, vinylidene compounds and vinylene compounds. Is preferred.
Examples of commercial products of vinyl polymers include polyacrylic acids such as Aron AC-10SL (manufactured by Toagosei Co., Ltd.), Joncryl 67, 611, 678, 680, 690 (manufactured by BASF Japan Ltd.), etc. Styrene-acrylic resins and the like.

The polymer is preferably dispersed in an aqueous ink as pigment particles A (pigment particles A) dispersed with a polymer or polymer particles B containing no pigment. Hereinafter, the polymer constituting the pigment particle A is also referred to as “polymer a”, and the polymer constituting the polymer particle B not containing a pigment is also referred to as “polymer b”.
The content of the polymer in the aqueous ink (the total amount of the polymer a and the polymer b) is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass from the viewpoint of pigment dispersibility and fixability. % Or more, and preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less.

[Polymer a]
The polymer a is a polymer having pigment dispersing ability, and examples thereof include polyester, polyurethane, vinyl polymer and the like. Among these, from the viewpoint of improving ink stability, vinyl polymers obtained by addition polymerization of vinyl monomers are preferable.
The vinyl polymer preferably contains (a1) a structural unit derived from an ionic monomer and (a2) a structural unit derived from a nonionic monomer.

As the ionic monomer (a1), an anionic monomer is preferable, and a carboxylic acid monomer, a sulfonic acid monomer and the like can be mentioned. Among these, carboxylic acid monomers are more preferable, and one or more selected from acrylic acid and methacrylic acid are more preferable.
The nonionic monomer (a2) is a monomer having a high affinity to water and a water-soluble organic solvent, and is preferably a polyalkylene glycol (meth) acrylate or an alkoxypolyalkylene glycol (meth) acrylate, and methoxy polyethylene glycol (n = 1 To 30) (meth) acrylates are more preferred. Examples of commercially available nonionic monomers include NK ester M series manufactured by Shin-Nakamura Chemical Co., Ltd., Blenmar PE series manufactured by NOF Corporation, PME series, 50 PEP series, 50 POEP series, and the like.

The polymer a may further contain a constituent unit derived from (a3) a hydrophobic monomer. Examples of the hydrophobic monomer (a3) include alkyl (meth) acrylates, aromatic group-containing monomers, and macromonomers having a polymerizable functional group at one end.
As the alkyl (meth) acrylate, one having an alkyl group having 6 to 18 carbon atoms is preferable, and, for example, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, (iso or tertiary) Li) butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate and the like.
The aromatic group-containing monomer is preferably a vinyl-based monomer having an aromatic group having 6 to 22 carbon atoms, and more preferably a styrene-based monomer, an aromatic group-containing (meth) acrylate or the like. As a styrene-based monomer, styrene, 2-methylstyrene, α-methylstyrene, vinyl toluene, divinylbenzene and the like are preferable, and as the aromatic group-containing (meth) acrylate, benzyl (meth) acrylate and the like are preferable.

(Content of each structural unit in polymer a)
The content of the constituent unit derived from the components (a1) to (a3) in the polymer a is as follows from the viewpoint of improving the dispersion stability of the ink.
The content of the component (a1) is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less More preferably, it is 20% by mass or less.
The content of the component (a2) is preferably 20% by mass or more, more preferably 40% by mass or more, still more preferably 60% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less More preferably, it is 85% by mass or less.
The content of the component (a3) is preferably 15% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less.

(Production of Polymer a)
The polymer a can be produced by copolymerizing a monomer mixture containing (a1) an ionic monomer, (a2) a nonionic monomer or the like by a known solution polymerization method or the like.
The weight average molecular weight of the polymer a is at least 3,000, more preferably at least 5,000, still more preferably at least 10,000 from the viewpoint of improving the dispersion stability of the ink and the fixability to the printing substrate, and Preferably it is 100,000 or less, More preferably, it is 50,000 or less, More preferably, it is 30,000 or less.
The acid value of the polymer a is preferably 100 mg KOH / g or more, more preferably 150 mg KOH / g or more, still more preferably 200 mg KOH / g or more, and preferably 350 mg KOH or more from the viewpoint of pigment dispersibility and polymer adsorptivity. / G or less, more preferably 300 mg KOH / g or less, still more preferably 250 mg KOH / g or less.
In addition, the measurement of a weight average molecular weight and an acid value can be performed by the method as described in an Example.

(Production of pigment particles A dispersed with polymer)
The pigment particles A dispersed with a polymer are particles in which the polymer a is adsorbed on the pigment surface, and can be stably dispersed in the ink.
The pigment particles A can be efficiently produced by a method having the following step I as a dispersion. Furthermore, you may manufacture by the method of having the following process II and process III.
Step I: Step of dispersing the mixture containing polymer a, organic solvent, pigment, and, if necessary, neutralizing agent, surfactant and the like to obtain a dispersion of pigment particles A Step II: obtained in step I Step of removing the organic solvent from the dispersion to obtain an aqueous dispersion of pigment particles A Step III: Mix the dispersion obtained in Step I or the aqueous dispersion obtained in Step II with a crosslinking agent, Step of cross-linking treatment to obtain an aqueous dispersion of pigment-containing polymer a particles (pigment particles A) The polymer a of the pigment particles A and the polymer b of the polymer particles 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 compositions but different only in the presence or absence of the pigment.

When the polymer a is an anionic polymer, a neutralizing agent may be used to neutralize anionic groups in the polymer. When using a neutralizing agent, it is preferable to neutralize so that pH may be 7 or more and 11 or less. Examples of the neutralizing agent include bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia and various amines. In addition, the polymer may be neutralized in advance.
From the viewpoint of improving the dispersion stability of the ink, the degree of neutralization of the anionic group of the polymer a is preferably 10 mol% or more and 100 mol% or less, more preferably 20 mol% or more and 90 mol% or less. Preferably, 30 mol% or more and 80 mol% or less are more preferable.

When the polymer a is an anionic polymer having an anionic group, the crosslinking agent is preferably a compound having a functional group which reacts with the anionic group, more preferably a compound having two or more of the functional groups in the molecule, Compounds having 2 or more and 6 or less therein are more preferable.
Preferred examples of the crosslinking agent include compounds having two or more epoxy groups in the molecule, compounds having two or more oxazoline groups in the molecule, and compounds having two or more isocyanate groups in the molecule. Among these, compounds having two or more epoxy groups in the molecule are preferable, and trimethylolpropane polyglycidyl ether is more preferable.
The crosslinking ratio of the acid component in the polymer a is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% or more from the viewpoint of storage stability of the ink, and preferably 80 It is at most mol%, more preferably at most 70 mol%, further preferably at most 60 mol%.

The content of pigment particles A in the ink is preferably 1% 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 fixability, and preferably 40 It is not more than mass%, more preferably not more than 35 mass%, still more preferably not more than 30 mass%.
The content of the polymer a in the ink is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and still more preferably 0.3% by mass or more from the viewpoint of fixability, and preferably Is 10% by mass or less, more preferably 5% by mass or less, still more preferably 2% by mass or less.
The mass ratio of the polymer a to the pigment in the ink [polymer a / pigment] is preferably 0.2 / 99.8 to 70/30, more preferably 0.5 / 99. From the viewpoint of improving the ink stability. It is 5 to 60/40, more preferably 1/99 to 50/50.

(Polymer particles B containing no pigment)
The water-based ink preferably contains pigment-free polymer particles B (polymer particles B) from the viewpoint of film formation on a printing substrate to improve fixability. The polymer particle B is a water-insoluble polymer particle which does not contain a pigment and is composed of a polymer alone.
Examples of the polymer b constituting the polymer particles B include acrylic resins, styrene resins, urethane resins, polyester resins, styrene-acrylic resins, butadiene resins, vinyl chloride resins, etc. Acrylic resins and vinyl chloride-acrylic resins are preferable from the viewpoints of improving the image quality and suppressing plate fog, and their combined use is also preferable.
The polymer particle B is preferably used as a water dispersion in which it is dispersed in water. As the polymer particle B, one synthesized appropriately may be used, or a commercially available product may be used.

[Polymer b]
The acrylic resin is preferably a water-insoluble vinyl polymer obtained by copolymerizing a monomer mixture B containing (b1) an ionic monomer and (b2) a hydrophobic monomer.
The component (b1) is the same as the component (a1), but among them, from the viewpoint of improving the dispersion stability, an anionic monomer is preferable, a carboxylic acid monomer is more preferable, and acrylic acid and methacrylic acid are selected. One or more of the above are more preferable.
As the component (b2), the same alkyl (meth) acrylate as that of the component (a3), an aromatic group-containing monomer, a macromonomer and the like can be mentioned. Among these, alkyl (meth) acrylates are preferable, those having an alkyl group having 1 to 22 carbon atoms, preferably 1 to 10 carbon atoms are more preferable, and the above exemplified compounds are more preferable, and methyl (meth) acrylate is more preferable. Even more preferred is the combined use with 2-ethylhexyl (meth) acrylate.

(Content of each constituent unit in polymer b)
The content of the constituent unit derived from the components (b1) and (b2) in the polymer b is as follows from the viewpoint of improving the fixability to the printing substrate.
The content of the component (b1) is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less More preferably, it is 15% by mass or less.
The content of the component (b2) is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and preferably 99% by mass or less, more preferably 97% by mass or less More preferably, it is 95 mass% or less.

The polymer b can be produced by copolymerizing a monomer mixture containing (b1) an ionic monomer, (a2) a nonionic monomer or the like by a known solution polymerization method or the like.
Commercially available examples of the dispersion of the polymer particles B include acrylic resin such as Neocryl A1127 (manufactured by DSM NeoResins, anionic self-crosslinking water-based acrylic resin), Joncryl 390 (manufactured by BASF Japan Ltd.), WBR-2018 Urethane resin such as Taisei Fine Chemical Co., Ltd., styrene-butadiene resin such as SR-100 (Nippon A & L Co., Ltd.), Joncryl 7100, 734, 538 (above, BASF Japan Co., Ltd.) Examples thereof include styrene-acrylic resins, and vinyl chloride-acrylic resins such as Binibran 700 and 701 (manufactured by Nisshin Chemical Industry Co., Ltd.).

The weight average molecular weight of the polymer b is preferably 100,000 or more, more preferably 200,000 or more, still more preferably 300,000 or more, and preferably 2,500,000 or less, more preferably 1,000,000 or less from the viewpoint of fixability. More preferably, it is 600,000 or less.
The acid value of the polymer b is preferably 1 mg KOH / g or more, more preferably 3 mg KOH / g or more, still more preferably 5 mg KOH / g or more, and preferably 70 mg KOH / g or less, more preferably, from the viewpoint of ink stability. Is 65 mg KOH / g or less, more preferably 60 mg KOH / g or less.
In addition, the weight average molecular weight and acid value of the polymer b are measured by the method as described in an Example.

The content of the polymer particles B in the ink is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, from the viewpoint of the fixability of the ink, and preferably 30% by mass. % Or less, more preferably 20% by mass or less, still more preferably 15% by mass or less.
The mass ratio of the polymer (total amount of polymer a and polymer b) to the pigment in the ink [polymer / pigment] is preferably 20/100 to 300/100, more preferably 30/100 to 100, from the viewpoint of the stability of the ink. It is 200/100, more preferably 40/100 to 100/100.

<Organic solvent>
As an organic solvent used for water-based ink, a water-soluble organic solvent is preferable. The water-soluble organic solvent is an organic solvent which is liquid or solid at normal temperature, and the amount of dissolution when dissolving the solvent in 100 ml of water at 25 ° C. is 10 ml or more.
The organic solvent preferably has a boiling point of 100 ° C. or more, more preferably 110 ° C. or more, still more preferably 115 ° C. or more, still more preferably 118 ° C. or more, from the viewpoint of improving ink transferability and suppressing plate fog. And preferably 260 ° C. or less, more preferably 250 ° C. or less, still more preferably 240 ° C. or less, still more preferably 235 ° C. or less.
Here, the boiling point refers to a standard boiling point (boiling point at 1 atm), and in the case of using two or more types, a weighted average value weighted by the content (mass%) of each water-soluble organic solvent.
The content of the organic solvent used in the aqueous ink is from the viewpoint of improving the ink transferability and suppressing the plate fog, the content of the organic solvent having a boiling point of 100 ° C. or more and 260 ° C. or less is preferably in the aqueous ink, preferably 0. 3% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, still more preferably 3% by mass or more, and from the viewpoint of environmental load reduction, preferably 12% by mass or less, more preferably Is 11% by mass or less, more preferably 10% by mass or less, and still more preferably 9% by mass or less.

The water-based ink may contain an organic solvent having a boiling point of less than 100 ° C., but in view of improving the ink transferability and suppressing the plate fog while suppressing the drying property, the content thereof is in the water-based ink And 5% by mass or less, preferably 3% by mass or less, and more preferably 1% by mass or less.
Examples of the organic solvent below 100 ° C. include monohydric alcohols such as ethanol, isopropyl alcohol and n-propyl alcohol.

Preferred water-soluble organic solvents include propylene glycol, polyhydric alcohols such as glycerin, polyhydric alcohol ethers, nitrogen-containing heterocyclic compounds, amides, amines and the like, among which glycol ethers are preferred.
As said glycol ether, the carbon number of an alkyl group is 1 or more, preferably 2 or more, and preferably 6 or less, more preferably 4 or less, still more preferably 3 or less, alkylene glycol monoalkyl ether, alkylene glycol And dialkyl ethers.
Among these, ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, etc. Ethylene glycol monomethyl ether (boiling point 125 ° C.), ethylene glycol monoisopropyl ether (boiling point 142 ° C.), ethylene glycol monobutyl ether (boiling point 171 ° C.), diethylene glycol monoisobutyl ether (boiling point 220 ° C.), propylene glycol monomethyl ether Boiling point 121 ° C.), and one or more is more preferably selected from triethylene glycol monomethyl ether (boiling point 249 ° C.).

<Surfactant>
The surfactant used in the aqueous ink is not particularly limited, but from the viewpoint of improving the ink transferability and suppressing the plate fog, silicone surfactants and acetylene glycol surfactants are preferable.
As a silicone type surfactant, a polyether modified silicone type surfactant is preferable. The polyether modified silicone surfactant has a structure in which the side chain and / or terminal hydrocarbon group of silicone oil is substituted with a polyether group. The polyether group is preferably a polyethyleneoxy group, a polypropyleneoxy group, or a polyalkyleneoxy group in which an ethyleneoxy group (EO) and a propyleneoxy group (PO) are added in block form or in a random manner. It is possible to use a compound in which an ether group is grafted, a compound in which a silicone and a polyether group are bound in a block, and the like.
Specific examples of the polyether-modified silicone surfactant include KF series manufactured by Shin-Etsu Chemical Co., Ltd., Silface SAG manufactured by Nisshin Chemical Co., Ltd., BYK series manufactured by Big Chemie Japan Co., Ltd., and the like.

As the acetylene glycol surfactant, acetylene glycol having 8 to 22 carbon atoms and ethylene adduct of the acetylene glycol are preferable, and acetylene glycol having 8 to 22 carbon atoms is more preferable.
Examples of these commercially available products include Surfynol 104 (2,4,7,9-Tetramethyl-5-decyne-4,7-diol) available from Air Products & Chemicals, and ethylene glycol 50 available from Surfynol 104. % Diluted product), 104 PG-50 (50% propylene glycol diluted product of Surfynol 104), Surfynol 420 (EO average 1.3 mol adduct of Surfynol 104), Acetylenol E13 T (Kawaken Fine Chemical Co., Ltd.) EO average added mole number: 1.3) and the like.

As the surfactant, other surfactants other than the above may be included. As other surfactant, nonionic surfactant is preferable and alcohol surfactant is more preferable.
Examples of commercial products of alcohol surfactants include "Emulgen" series manufactured by Kao Corporation.
The content of the surfactant in the ink is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, as the total amount of the surfactant from the viewpoint of improving the wettability to the printing substrate More preferably, it is 0.4% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less.

(Thickener etc.)
The aqueous ink can contain various additives such as a thickener, a pH adjuster, an antifoamer, an antiseptic agent, a rust inhibitor, and the like as optional components.
Examples of the thickener include cellulose-based thickeners, polyacrylic acid-based thickeners, polyether polyol-based thickeners, polyether urethane-modified thickeners and the like.
Examples of commercial products of polyacrylic acid-based thickeners include Primal ASE series manufactured by Rohm & Haas, etc. Examples of commercial products of polyether polyol-based thickeners include RHEOLATE series manufactured by RHEOX, etc. Polyether urethane Examples of commercially available modified thickeners include Adekanol UH series manufactured by ADEKA Co., Ltd., and DK Thickener SCT series manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Although the compounding quantity of a thickener is suitably adjusted according to desired viscosity, it is 0.1 mass% or more and 5 mass% or less in water-based ink normally.

(water)
The content of water in the water-based ink is preferably 45% by mass or more, more preferably 50% by mass or more, still more preferably 55% by mass or more, and from the viewpoint of improving the ink transferability and suppressing the plate fog. It is preferably at most 75% by mass, more preferably at most 70% by mass, still more preferably at most 65% by mass.

<Physical properties of water-based ink>
The average particle diameter in the ink of pigment particles, particularly pigment particles A in which the pigment is dispersed in a polymer, is preferably 120 nm or more, more preferably 130 nm or more, from the viewpoint of improving ink transferability and suppressing plate fog. It is preferably 140 nm or more, still more preferably 150 nm or more, and preferably 350 nm or less, more preferably 340 nm or less, still more preferably 320 nm or less, still more preferably 300 nm or less.
The average particle diameter in the ink of polymer particles B not containing a pigment is preferably 20 nm or more, more preferably 40 nm or more, still more preferably 60 nm or more, from the viewpoint of improving ink transferability and suppressing plate fog. And, preferably 300 nm or less, more preferably 200 nm or less, further preferably 150 nm or less.
The average particle diameter of the pigment particles A and the polymer particles B is measured by the method described in the examples.

The static surface tension of the water-based ink at 20 ° C. is 23 mN / m or more and 30 mN / m or less from the viewpoint of improving the ink transferability and suppressing the plate fog. The static surface tension is preferably 24 mN / m or more, more preferably 25 mN / m or more, and preferably 29 mN / m or less, more preferably 28 mN / m or less.
The static surface tension of the ink is measured by the method described in the examples.
The viscosity of the ink at 20 ° C. by the Zahn cup method is preferably 10 seconds or more, more preferably 12 seconds or more, still more preferably 14 seconds or more, from the viewpoint of improving ink transferability and suppressing plate fog. Preferably it is 25 seconds or less, More preferably, it is 23 seconds or less, More preferably, it is 21 seconds or less.
The pH of the ink at 20 ° C. is preferably 5.5 or more, more preferably 6.0 or more, still more preferably 6.5 or more, from the viewpoint of improving the dispersion stability, and member resistance, skin irritation Preferably, it is 11.0 or less, more preferably 10.0 or less, still more preferably 9.5 or less.

  In the following production examples, preparation examples, examples and comparative examples, "parts" and "%" are "parts by mass" and "% by mass" unless otherwise specified. In addition, the measuring method of each physical property etc. is as follows.

(1) Measurement of Weight Average Molecular Weight of Polymer The molecular weight of the polymer is determined by using a solution of phosphoric acid and lithium bromide dissolved in N, N-dimethylformamide so as to have concentrations of 60 mmol / L and 50 mmol / L, respectively. The gel permeation chromatography method (GPA apparatus manufactured by Tosoh Corp. (HLA-8120 GPA), Tosoh Corp. column (TSK-GEL, α-M × 2), flow rate: 1 mL / min) was measured. In addition, monodispersed polystyrene of known molecular weight was used as a standard substance.

(2) Measurement of acid value of polymer Dissolve the resin in a titration solvent in which toluene and acetone (2 + 1) are mixed in a potentiometric automatic titrator (manufactured by Kyoto Denshi Kogyo Co., Ltd., motorized burette, model number: APB-610), and conduct potentiometric titration It titrated with the 0.1N potassium hydroxide / ethanol solution by the method, and made the inflexion point on the titration curve the end point. The acid number was calculated from the titer to the end of the potassium hydroxide solution.

(3) Measurement of solid content concentration Into a 30 ml polypropylene container (φ = 40 mm, height = 30 mm), weigh 10.0 g of sodium sulfate that has been homogenized in a desiccator, and add about 1.0 g of a sample to it. After mixing, the mixture was accurately weighed and maintained at 105 ° C. for 2 hours to remove volatiles, and then left in a desiccator for 15 minutes to measure the mass. The mass of the sample after devolatilization was regarded as solid content, and was divided by the mass of the added sample to obtain solid concentration.

(4) Measurement of average particle diameter of pigment particles A and polymer particles B not containing pigment The cumulant average particle diameter is measured using a laser particle analysis system (manufactured by Otsuka Electronics Co., Ltd., model number: ELS-8000, cumulant analysis) The cumulant average particle size is defined as the average particle size of pigment particles A or the average particle size of polymer particles B containing no pigment. As a measurement sample, a dispersion diluted with water so that the concentration of particles to be measured was 5 × 10 ⁻³ % was used. The measurement conditions were a temperature of 25 ° C., an angle of 90 ° between the incident light and the detector, and an integration count of 100. The refractive index of water (1.333) was input as the refractive index of the dispersion solvent.

(5) Measurement of static surface tension of water-based ink A cylindrical polyethylene container (diameter: 5 g of water-based ink containing platinum plate, using a surface tension meter (trade name: CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.) It was immersed in 3.6 cm × depth 1.2 cm), and the static surface tension of the water-based ink was measured at 20 ° C.

Production Example 1 (Production of Pigment Water Dispersion A)
(1) Measure 236 parts of deionized water in a 2 L flask, 60 parts of acrylic polymer (manufactured by BASF, trade name: Joncryl 690, weight average molecular weight 16500, acid value 240 mg KOH / g, Tg 105 ° C.) and 5 N hydroxylation 36.5 parts (sodium neutralization degree 60 mol%) of sodium solution was charged. The mixture was stirred at 200 rpm for 2 hours using an anchor wing to obtain 332.5 parts (solid content concentration 19.9%) of an aqueous acrylic polymer solution.
331.7 parts of the above aqueous solution and 448.3 parts of ion-exchanged water are added to a vessel having a volume of 2 L having a spar wing, and cooled with a 0 ° C. water bath while using a disper (manufactured by Asada Iron Works Co., Ltd .; The solution was stirred at 1400 rpm for 15 minutes.
(2) Next, 220 parts of carbon black (manufactured by Mitsubishi Chemical Corporation, trade name: # 40, primary particle diameter 24 nm) was added, and the mixture was stirred at 6400 rpm for 1 hour. The dispersion is introduced into a wet disperser (manufactured by Hiroshima Metal & Machinery Co., Ltd., trade name: Ultra Apex Mill UAM 05) filled with 80% of zirconia beads (made by Nikkato Co., trade name: XTZ ball, 0.3 mmφ) The dispersion was dispersed in 5 passes at a peripheral speed of 8 m / s and a flow rate of 200 g / min while cooling with cooling water at 5 ° C., followed by filtration using a 200-mesh wire mesh.
(3) 7.3 parts of Denacol EX-321L (Nagase Chemtex Co., Ltd., trimethylolpropane polyglycidyl ether, epoxy equivalent: 129) in 500 parts of the filtrate obtained above (110 parts of pigment, 33 parts of polymer) (polymer Add 1 part of Proxel LV (S) (manufactured by Lonza Japan Co., Ltd., a mildew proofing agent, 20% active ingredient) with respect to the carboxylic acid which becomes a crosslinking reaction point contained in acrylic acid in it, and further solidify After adding 17.9 parts of ion-exchanged water so that the concentration would be 28.6%, and stirring at 70 ° C. for 3 hours, filter with a 200 mesh wire mesh and 28.6% of polymer particles containing pigment. 526.2 parts of dispersion A (pigment water dispersion A; average particle diameter 190 nm) were obtained.

Production Example 2 (Production of Water-Insoluble Polymer Particle Dispersion Containing No Pigment)
In a reaction container equipped with a dropping funnel, 0.5 parts of methacrylic acid, 14.5 parts of methyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.), 5.0 parts of 2-ethylhexyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.) Latemul E-118 B (11.1 parts of sodium polyoxyethylene alkyl ether sulfate, manufactured by Kao Corporation, surfactant), 0.2 parts of potassium persulfate (manufactured by Wako Pure Chemical Industries, Ltd.) which is a polymerization initiator, After 282.8 parts of ion-exchanged water was added and mixed at 150 prm, nitrogen gas substitution was performed to obtain an initially charged monomer solution.
9.5 parts of methacrylic acid, 275.5 parts of methyl methacrylate, 95.0 parts of 2-ethylhexyl acrylate, 35.1 parts of Latemul E-118 B, 0.6 parts of potassium persulfate, 183.0 parts of ion exchanged water at 150 prm The mixed dropping monomer solution was placed in the dropping funnel to carry out nitrogen gas substitution.
Under a nitrogen atmosphere, the initial charged monomer solution in the reaction vessel is heated from room temperature to 80 ° C. over 30 minutes while being stirred at 150 prm, and while maintaining at 80 ° C., the monomers in the dropping funnel are gradually taken over 3 hours It dripped in the reaction container. After completion of the dropwise addition, the mixture was stirred for 1 hour while maintaining the temperature in the reaction vessel, and 204.7 parts of ion exchanged water was added. Then, the resultant was filtered through a stainless steel wire mesh (200 mesh) to obtain a dispersion of water-insoluble polymer particles (solid content concentration 40%, average particle diameter 100 nm, acid value 16 mg KOH / g, Tg 48 ° C.).

Preparation of Ink for Gravure Printing
Preparation Example 1 (Preparation of Ink 1)
A neutralizer was added to 54.5 parts of the pigment water dispersion A obtained in Production Example 1 (corresponding to a pigment concentration of 11.5% in the ink) in the production container so that the ink composition described in Table 1 was obtained. 19.5 parts of a dispersion of water-insoluble polymer particles not containing the pigment obtained in .77 parts (Wako Pure Chemical Industries, Ltd., 5N sodium hydroxide solution) and Preparation Example 2 (polymer concentration in ink 8.0 %, Solid content concentration 41%) was added, and stirring was performed at 150 rpm.
Furthermore, 7 parts of diethylene glycol monoisobutyl ether, 1.0 part of silicone surfactant (Shin-Etsu Chemical Co., Ltd., trade name: KF-6011, PEG-11 methyl ether dimethicone) and acetylene glycol surfactant 1.0 part (Nisshin Chemical Industry Co., Ltd., trade name: Surfynol 104PG50, 2,4,7,9-Tetramethyl-5-decyne-4,7-diol, active ingredient 50%, propylene glycol solution), thickener After adding 0.8 parts (made by ADEKA, trade name: Adecanol UH-420, active 30% aqueous solution) and 15.4 parts of ion-exchanged water and stirring for 30 minutes at room temperature, a stainless steel wire mesh (200 The solution was filtered through a mesh to obtain an ink 1.

The symbols in Table 1 indicate the following.
・ IBDG: diethylene glycol monoisobutyl ether (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 220 ° C., SP value 8.7)
MFG: Propylene glycol monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 121 ° C., SP value 10.4)
・ MTG: triethylene glycol monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 249 ° C., SP value 10.5)
・ IPA: isopropyl alcohol (Wako Pure Chemical Industries, Ltd., boiling point 88 ° C., SP value 11.5)
BTG: triethylene glycol monobutyl ether (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 271 ° C., SP value 9.6)

Preparation Examples 2 to 9 (Preparation of Inks 2 to 9)
Inks 2 to 9 were obtained in the same manner as in Preparation Example 1, except that the formulation of Preparation Example 1 was changed to the conditions shown in Table 1.

Example 1
Using the ink of Preparation Example 1, printing was performed on a corona-discharge-treated surface of a biaxially stretched polypropylene film (Futamura Chemical Co., Ltd., trade name: FOR-AQ # 20, laminate grade, thickness 20 μm). Printing is performed by gravure roll A (manufactured by NABE PROCESS, laser platemaking method, roll diameter 200 mm, roll length 1100 mm, gravure 250 lines, cell depth 8 μm, paper polishing process # 1000) and doctor blade (manufactured by Echo Blade Co., Ltd.) Ceramic composite doctor, plating: printing with a gravure printer (Okazaki Machine Industry Co., Ltd., Gravure 3-color test machine) equipped with nickel / ceramic composite type, Vickers hardness 850 Hv, plating thickness 10 μm, cutting edge thickness 90 μm, parallel blade) Speed: 75m / min, drying temperature 70 ° C, finisher roll material NBR, finisher roll pressure 0.25MPa, finisher rotation speed 15% for 100% gravure roll, contact pressure between doctor blade and gravure roll 0.15 MPa, nip Ra material NBR, nip rolls were subjected to printing under conditions of contact pressure 0.15MPa in contact with the printing substrate (see FIG. 1).

Examples 2-11, Comparative Examples 1-10
Example 1 was carried out in the same manner as Example 1 except that the conditions in Example 1 were changed to the conditions shown in Table 2 and Table 3.

<Evaluation of ink>
The ink transfer rate and the plate fog density were evaluated for the obtained ink by the following evaluation method. The results are shown in Tables 2 and 3.

<Evaluation method of ink transfer rate>
A 100 mm × 100 mm solid printed matter printed with 100% dots was cut, the initial mass was measured, and the ink was removed with ben cotton using acetone. Thereafter, the printed matter was dried with warm air at 40 ° C. for 12 hours, and the mass was measured. The difference between the initial mass and the mass after ink removal and drying was taken as the ink transfer amount. The transfer rate (%) of the ink was calculated from the following formula from the cell (recessed portion) volume of the gravure roll plate surface and the ink transfer amount, and was evaluated according to the following criteria.
Ink transfer rate (%) = (ink transfer amount / gravure cell volume) x 100
(Evaluation criteria)
:: Ink transfer rate 61 to 70%
○: Ink transfer rate 56 to 60%
Δ: Ink transfer rate 51 to 55%
X: Ink transfer rate 40 to 50%
以上 or more is a level that causes no practical problems.

<Method for evaluating plate fog density>
Using a spectrophotometer (Gretag Macbeth, trade name: SpectroEye), cut 10 unprinted non-image areas, stack 10 of them, and measure in the density measurement mode (DIN, Abs) Conducted and evaluated according to the following criteria.
(Evaluation criteria)
:: plate fog density 0.30 to 0.35
○: Plate cover density 0.36 to 0.40
:: plate cover density 0.41 to 0.45
X: Plate cover density 0.46 to 0.55
以上 or more is a level that causes no practical problems.

  From Tables 2 and 3, according to the printing method of Examples 1 to 11, the ink transfer rate is high compared to the printing methods of Comparative Examples 1 to 10, and stable printing can be performed in continuous printing, and at the same time the plate fog is It is understood that high quality printed matter can be obtained by being suppressed.

1: Gravure printing machine 10: Ink pan 11: Finisher roll 12: Gravure roll 13: Doctor blade 14: Nip roll 15: Printing substrate supply roll 16: Printing substrate winding roll 20: Printing substrate

Claims (4)

A gravure printing method in which aqueous ink is stored in an ink pan and printed using a finisher roll and a gravure roll,
The aqueous ink comprises a pigment, a polymer, an organic solvent, a surfactant and water.
The content of the organic solvent having a boiling point of less than 100 ° C. in the aqueous ink is 5% by mass or less,
The static surface tension at 20 ° C. of the water-based ink is from 23 mN / m to 30 mN / m,
The rubber hardness of the finisher roll is 55 ° or more and 85 ° or less,
The contact pressure with which the finisher roll contacts the gravure roll is 0.08 MPa or more and 0.4 MPa or less,
The gravure printing method, wherein the rotation speed of the finisher roll is 4% or more and 28% or less with respect to 100% of the rotation speed of the gravure roll.   The gravure printing method according to claim 1, wherein the material used for the finisher roll is at least one selected from acrylonitrile-butadiene rubber, ethylene propylene rubber, and butyl rubber.   The gravure printing method of Claim 1 or 2 whose content of surfactant in water-based ink is 0.1 to 10 mass%.   The gravure printing method according to any one of claims 1 to 3, wherein the content of the organic solvent having a boiling point of 100 ° C or more and 260 ° C or less in the organic solvent is 0.3% by mass or more and 12% by mass or less.