JP2018002956A - Printing ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing ink composition which exhibits excellent abrasion resistance, shows excellent an anti-blocking effect and solves problems of plate stain and blanket stain.SOLUTION: A printing ink composition is formed by dispersing composite particles having a volume average particle size of 2-8 μm, a volume content of solid polymer particles with a particle size of more than 10 μm of 20 vol.% or less and a degree of sphericity of 0.95 or more, in printing ink. The composite particles (A) are composed of solid polymer particles (A-1) like wax which are not dissolved in the printing ink, and inorganic fine particles (A-2) which are mainly bonded to the outer peripheries of the solid polymer particles and have an average particle size of 5-1,000 nm.SELECTED DRAWING: None

Description

  The present invention relates to a printing ink composition, and more particularly to a printing ink composition suitable for a room temperature drying type lithographic printing ink for offset sheets and a heat drying type lithographic printing ink for offset rotation.

  Generally, the printed surface of a printed material printed with an offset lithographic printing ink is rubbed in contact with a guide roll, a turn bar, a triangular plate, or the back surface of another printed material immediately after printing. Further, the printing surface causes a so-called blocking phenomenon in which the printed ink composition is fused to the surface of the contact object, thereby causing a problem that the printing surface is significantly deteriorated and the contact object surface is contaminated.

  In order to solve such problems, fine particles made of a solid polymer such as resin or wax are added to the printing ink to form fine protrusions that give lubricity to the printed surface after printing. It has been attempted to improve wear resistance.

  Usually, since the thickness of the printing ink is about 0.2 to 1.0 μm, the particle size of the solid polymer particles for forming such slippery protrusions on the printed surface is in a certain range of 1.0 μm or more. It is desirable that it is adjusted. The reason is that if the particle size of the solid polymer particles is less than 1.0 μm, the solid polymer particles are buried in the printed ink layer and the effect as a lubricant cannot be obtained. If the particle size of the molecular particles is too large, the particles remain on the inking roll, plate or blanket during printing, and this gradually accumulates and pilings to deteriorate the print image quality, or agglomerate on the plate to produce protrusions. This is because a so-called Hicky phenomenon occurs in which the portion is white.

  However, it is difficult to adjust the solid polymer particles to such a desired particle size range and stably disperse them in the ink. At present, plate stains and blanket stains caused by the inclusion of large particle size particles The problem has not been fully solved.

  In the case of high-speed printing, there is also a problem that causes so-called misting in which solid polymer particles are separated and scattered when the ink is transferred from the plate. These are due to the fact that the solid polymer particles have a low affinity with the ink vehicle. From this viewpoint, it is important to modify the surface of the dispersed particles to an interface having an affinity with the vehicle.

  In high-speed offset printing, the printed material is exposed to a high temperature for drying, but when the paper surface temperature at this time reaches 100 ° C. or more, the solid polymer particles melt and become flattened, and the intended wear resistance is achieved. It can no longer be obtained. For this reason, in recent years, solid polymer particles having a high melting point have been used. However, in such a high melting point solid polymer particle, the average particle size can be reduced to about 1 to 10 μm. It has become a more difficult problem.

  The sliding property between the printed surface and the back surface or other material surface is also important, and wax or the like existing as protrusions on the surface of the printed surface sometimes achieves a significantly low coefficient of friction. It becomes difficult to stack. As a method for adjusting this, inorganic powder having an appropriate particle diameter is added to the printing ink, but the transparency and gloss of the printed matter are lowered, and reliable control of the friction coefficient has not been realized.

  The same applies to the case of UV curable ink sheet-fed printing, and a blocking phenomenon occurs in which undried ink or peeled ink adheres when the drying by sufficient UV irradiation cannot be obtained and the printed matter becomes dirty. .

  Also in gravure printing, after printing on paper or film, the backside of the wound paper or film may become dirty with undried ink, and in severe cases, such as blocking phenomenon, or after printing There is a problem that the printed surfaces are rubbed due to contact between the printed surfaces and the printed surface.

  In order to solve such problems, current, especially oxidation polymerization drying offset printing inks, spray corn starch, silicone-treated corn starch, silicone-treated tapioca starch, etc. on the printing surface to prevent the blocking phenomenon. However, spraying of these starches has many problems because it is highly likely to cause dust in the printing chamber due to dust, malfunction of the equipment, health hazards to the operator, and the like.

  In addition, starch, silicone-treated starch, and the like, which are fine particles that do not cause a problem in printability, are added to printing ink (for example, see Patent Document 1). However, even in this technique, a sufficient anti-set-off effect is not obtained, and the gloss of printed matter is severely lowered.

  In recent years, fine particles made of solid polymers such as olefin resin powder and wax are added to offset printing inks including gravure printing to form protrusions that give non-stickiness and lubricity to the printed surface after printing. It has been proposed to prevent the adhesiveness of the printed surface and improve the wear resistance (see, for example, Patent Document 2). The proposed fine particles of the solid polymer have a volume average particle size of 0.3 to 20 μm, and preferably 0.3 to 15 μm. However, when the volume average particle size of the fine particles made of such a solid polymer is 2 μm or less, the anti-blocking effect and the wear resistance effect are inferior, and the solid average particle size with a coarse average particle size of 10 μm or more is obtained. Molecules have a problem in printability, and a pile phenomenon such as a plate residue or a blanket residue occurs. Even if printing can be performed in an extremely small lot, the printed matter has a large protrusion and a solid polymer such as olefin resin powder or wax, the gloss is lowered due to poor wetting with the ink component.

  Furthermore, there is a similar proposal in which fine particles having an olefin resin powder particle size of 2 to 50 times the thickness of the printed layer are added (for example, see Patent Document 3). However, since the thickness of ordinary printed offset lithographic printing ink is about 0.2 to 2 μm, the average particle size of the olefin resin powder is 0.4 μm to 100 μm, and there are problems with printability and coarse particles with poor gloss of printed matter. Contains. Further, although this document proposes protective colloid particles as particles containing olefin resin on the surface other than the olefin resin, it is not sufficient in terms of wear resistance and prevention of blocking.

  There is also a proposal of a printing ink containing an acrylic / core-shell polymer (see, for example, Patent Document 4), but the printing ink in this proposal is inferior in wear resistance and antiblocking effect. There is also a proposal to add water-soluble polymer polyvinyl alcohol resin powder to printing ink (see, for example, Patent Document 5), but this proposal has a very poor wear resistance effect.

  As described above, it is desirable that the solid polymer particles have a particle size distribution adjusted to a certain range of 1.0 μm or more. From this point, the aqueous dispersion and the printing method (for example, refer to Patent Document 6) in which the addition of polyolefin wax having an average particle size of 0.08 to 0.3 μm is proposed have an antiwear effect and an antiblocking effect. Is significantly inferior.

  Conversely, if the particle size of the solid polymer particles is too large for the ink thickness, the particles will remain on the inking roll, plate or blanket during printing, and this will gradually accumulate and deteriorate the print image quality. This may cause a so-called Hicky phenomenon in which portions where the protrusions are aggregated on the plate are white. However, it is difficult to prepare solid polymer particles in such a desired particle size range and stably disperse them in ink. The problem has not been fully resolved.

  There is also a proposal for printing ink of a true spherical polyolefin wax having a particle diameter of 1.0 to 10.0 μm (see, for example, Patent Document 7). However, since the offset lithographic printing ink is oily, the offset lithographic ink using dampening water tends to lose the emulsification balance. In addition, the addition of a surfactant causes a problem in printability and causes a pile such as a plate residue. Furthermore, since the ink is poorly wet, the gloss of the printed matter is severely degraded.

  There is also a proposal to add a spherical polymethacrylate as having an effect of preventing set-off for UV (see, for example, Patent Document 8), but these particles have no wear resistance effect.

  In the case of high-speed printing, there is a problem that causes so-called misting in which solid polymer particles are separated and scattered when the ink is transferred from the plate. These are due to the fact that the solid polymer particles have a low affinity with the ink vehicle. From this viewpoint, it is important to modify the surface of the dispersed particles to an interface having an affinity with the vehicle.

  In this regard, the present applicant has already improved the anti-pyring property, good abrasion resistance, and maintained the gloss of the printed material, using a composite particle composed of wax and inorganic fine particles. The printing ink composition which can be performed is proposed (for example, refer patent document 9). By the way, this printing ink composition has generally good printability. However, particularly when used for a room temperature dry type sheet-fed ink of oxidative polymerization, it has further characteristics in blocking effect and prevention of impression cylinder stains. There is a need for improvement.

Japanese Patent Laid-Open No. 01-306481 Japanese Patent No. 3651892 JP 2010-47670 A Special table 2014-514367 gazette Japanese Patent No. 5669345 Japanese Patent No. 4143165 JP 2013-216734 A JP 07-331152 A Japanese Patent No. 4869946

  The present invention has been made to solve such conventional problems, and a main object of the present invention is to provide a printing ink composition in which the following problems have been solved in the printing ink.

(1) Provided is a printing ink composition that has excellent abrasion resistance, exhibits an excellent anti-blocking effect, and eliminates problems such as plate stains and blanket stains that do not cause a hicky phenomenon.
(2) Printing ink which gives a printed matter to which fine and solid polymer particles having a high melting point are added and the printing surface comes into contact with the printing surface during printing and the printed surface is free from plate stains and blanket stains with controlled rubbing against the back surface. A composition is provided.
(3) To provide a printing ink composition that does not deteriorate the surface gloss and transparency of a printing ink containing a solid polymer component for satisfying printing suitability such as viscoelastic properties.

(4) In a printing ink that contains a solid spherical polymer component that exhibits excellent wear resistance and has an excellent anti-blocking effect, the wear resistance is not limited even after undergoing a process of fixing the printed surface at high temperature. Provided is a printing ink composition in which the blocking property does not decrease.
(5) Provided is a printing ink composition containing a solid polymer component that exhibits excellent abrasion resistance and has an excellent anti-blocking effect in solvent gravure printing inks or aqueous flexographic inks.

  The printing ink composition of the present invention is a printing ink composition containing the composite particles (A) in the printing ink, wherein the composite particles (A) are not dissolved in the printing ink from a resin, wax, or a mixture thereof. Solid polymer particles (A-1) and inorganic fine particles (A-2) having an average particle diameter of 5 to 1000 nm attached to the surface thereof, and the composite particles (A) have a volume average particle diameter of 2 to 8 μm. The volume content of particles having a particle diameter exceeding 10 μm within the range is 20% by volume or less, and the sphericity of the composite particles (A) is 0.95 or more.

  The printing ink composition of the present invention has improved pile and printing residue, which has been a problem when conventional solid polymer particles are added, and wear resistance of the printed surface after printing and after printing. As a result, it is possible to remarkably reduce the blocking phenomenon caused by the stacking of printed materials.

  In addition, since the surface of the solid polymer particles is coated with inorganic fine particles, it has good affinity with the ink vehicle, does not cause a Hicky phenomenon, etc., and is especially a room temperature drying type lithographic printing ink for offset sheets. Further, since the lithographic printing ink for heat-drying type offset rotary printing is not taken by the impression cylinder and does not stain the impression cylinder, a printed matter having high gloss can be provided without staining the preprinted printed matter.

  Furthermore, the printing ink composition of the present invention has a remarkable effect of improving slipping characteristics even when a small amount of composite particles (A) having a high sphericity is added to the ink vehicle, and the sphericity is less than 0.95. Compared with a printing ink composition using complex particles, the addition of a small amount of composite particles can provide the same friction resistance and anti-blocking performance, and the amount added can be greatly reduced. Therefore, compared with the conventional composite particles, a printed matter can be provided without lowering transparency and gloss, and improvement in printability such as piling can be obtained.

  Further, even when solid polymer particles having a high melting point are used, the volume average particle diameter can be reduced to 2 to 8 μm by the action of inorganic fine particles.

2 is an electron micrograph of composite particles obtained in Example 2. FIG.

As described above, the present invention is a printing ink composition containing the composite particles (A) in the printing ink, and is particularly characterized by the composite particles (A). Hereinafter, the present invention will be described in more detail.
First, the printing ink used in the present invention is not particularly limited as long as it is a known printing ink, and an offset ink is particularly preferable.

  Examples of the offset ink used here include generally used oxidation polymerization type offset lithographic inks, ultraviolet curable offset lithographic inks, and solvent-type gravure inks.

  For example, as the oxidative polymerization type offset lithographic ink, carbon black of black ink, phthalocyanine blue of indigo ink, azo pigment such as brilliant carmine 6B of red ink and pigment yellow of yellow ink, quinacridone pigment, etc. 15-25 20% by mass of synthetic resin components such as rosin-modified phenolic resin, alkyd resin, petroleum resin, 20% semi-drying oil and drying oil such as soybean oil, linseed oil, soybean oil fatty acid butyl ester An ink composed of ˜40% by mass, 20-30% by mass of mineral oil such as aroma-free, and 1-10% by mass of auxiliary agents such as dryers and antioxidants can be used.

  Further, for example, as the ultraviolet curable lithographic ink, 15 to 25% by mass of the pigment used in the oxidation polymerization lithographic ink, and the fixing agent may be various acrylic prepolymers and monomers (for example, bisphenol A diglycidyl ether diacrylate, 60 to 70% by mass of a photopolymerization initiator (a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, trimethylolpropane triacrylate ethylene oxide, propylene oxide adduct, methacrylate, etc.) For example, radical reaction types include alkylphenone, acylphosphine oxide, oxime ester, intramolecular hydrogen abstraction type, cation reaction type, and blends thereof) 10 wt%, a polymerization inhibitor and inks hardness adjustment bentonite such as 5 to 10% by weight as auxiliaries, in the configured ink can be used.

  As the gravure ink, the pigment used in the offset lithographic ink can be used, the addition amount is 5 to 30% by mass, the extender pigment is, for example, fatty acid-treated calcium carbonate, rosin acid-treated calcium 0 to 5% by mass, and the fixing agent is (For example, synthetic resin such as nitrocellulose, butyral resin, alkyd resin, acrylic resin, rosin or mixed resin thereof) 20 to 40% by mass, solvent is low boiling point and solvent compatible with resin (for example, toluene , Ethyl acetate, isopropyl alcohol, propyl acetate alcohol, butyl alcohol, methylcyclohexane, cyclohexanone, ethylene glycols and mixtures thereof, etc.) 40 to 70% by mass, auxiliary agent such as anti-settling agent 0 to 10% by mass Used ink can be used.

  The composite particles (A) used in the present invention usually include a form in which the inorganic fine particles (A-2) are adhered (partially buried) so as to substantially cover the surface of the solid polymer particles (A-1). The volume average particle diameter is in the range of 2 to 8 μm. Here, the term “coating” means that a large number of inorganic fine particles (A-2) are scattered on the surface of the solid polymer particles (A-1) to such an extent as to suppress the blocking phenomenon and the hicky phenomenon. It does not have to be completely covered.

  The “volume average particle diameter” in the present specification is a value measured with a Coulter counter manufactured by Beckman Coulter. When the average particle diameter of the composite particles (A) contained in the printing ink composition is less than 2 μm, it is not preferable because the composite particles (A) do not act as an active ingredient that imparts wear resistance and blocking properties, which are the original purposes of the present invention. In addition, when the average particle size exceeds 8 μm, it is effective for improving the wear resistance and blocking property, but it causes a plate stain by being piled on a plate, a blanket or an inking roll. This is not preferable because it deteriorates glossiness and transparency. Even if the average particle size is 8 μm or less, particles containing a wide particle size distribution exceeding 10 μm in excess of 20% by volume are not preferable because they tend to be piled. In particular, the sphericity is important. When the sphericity of the spherical particles is 0.95 or more, the friction resistance is remarkably improved and the anti-blocking effect is excellent. However, the ink composition of the present invention causes no trouble on the printing press up to 20% by volume of particles having a size of 10 μm or more.

  The solid polymer particles (A-1) used in the present invention include resin particles such as fluororesin, polystyrene, polyacetal, epoxy resin, silicone resin, and natural wax, synthetic wax, polyethylene wax, polypropylene wax, ester wax, calcium stearate. Examples thereof include metal soaps such as zinc stearate, waxes such as amide wax, or particles having an average particle diameter of 0.1 to 30 μm made of this composite. As these particles, those having a melting point of 80 ° C. to 300 ° C. or a crosslinked product having no melting point can be used. In particular, an oxidized polyethylene wax having a melting point of 120 ° C. or higher and an acid value of 10 or higher is preferable. The wax used in the present invention is a general term for substances containing long hydrocarbon chains and having a viscosity that rapidly decreases at a certain temperature. In the present invention, the number of carbon atoms in the hydrocarbon chain is at least 10 or more. A wax containing a paraffin chain is suitable.

Moreover, this solid polymer particle (A-1) has a melting point of 120 ° C. or higher, and a needle with a weight of 100 g applied at 25 ° C. for 5 seconds in accordance with JIS K-2235-5.4. A wax having a penetration of 2.0 or less, which represents the depth of penetration into the film in units of 10 ⁻¹ mm, is preferred.

  The inorganic fine particles (A-2) used in the present invention include metal oxides selected from silica, alumina, titania, bentonite, montmorylnite, etc., metal nitrides such as aluminum nitride and boron nitride, and silicon carbide. Metal carbide, metal sulfides such as barium sulfate and calcium sulfate, fine particles made of one or a mixture of fluorides such as calcium carbonate, sulfides such as carbon disulfide, fluorite, and fluorocarbon. Having a thickness of 5 nm to 1000 nm is used. The average particle diameter of the inorganic particles (A-2) is a value measured by Nanotrack UPA EX manufactured by Nikkiso Co., Ltd. in a state of being dispersed in water. In general, particles having a particle size of 100 nm or less are measured as a particle size including aggregated particles. Since these primary average particle diameters can exist in the state adhering to the surface of the composite particles (A), the particle diameters in the actually used state are measured by an electron microscope image of the particle surfaces.

  The sphericity measurement was performed by measuring the circularity with an FPIA-3000 shape measuring instrument (trade name, manufactured by Malvern Division). Originally, it is necessary to measure whether the sphericity is spherical or not, but this measuring device measures an image obtained by dropping three-dimensional particles into two dimensions, and is obtained by measuring a large number of particles, for example, 300,000 particles. Since the numerical value is averaged to obtain a circularity, it can be regarded substantially as a sphericity, and is a method widely used in this field.

  The composite particles (A) are prepared by blending a base resin or solid polymer particles (A-1) and inorganic fine particles (A-2) in a desired ratio, then a Henschel mixer, a sand grinder, a bead mill, an attritor, a ball mill. , Kneader, roll mill, twin-screw kneader, tornado mill, jet mill, pin mill, mechanical mill, etc., and mixing at a high speed and under a high shear force at a desired temperature or lower. By this mixing, a composite in which the surface of resin particles or wax particles is uniformly coated with inorganic particles can be obtained. Spherical fine particles can be obtained from the spheroidizing equipment for spheroidizing this. For example, spheroidization was performed by a general spray drying method, a spray drying method using supercritical carbon dioxide, an emulsification method using an autoclave, and Meteole Inbo (manufactured by Nippon Pneumatic Industry Co., Ltd.), and the circularity was increased to 0.95 or more. Composite particles (A) can be obtained.

  Further, in the mixing step, fine particles are generated by crushing and abrasion of the solid polymer particles (A-1), and further inorganic fine particles adhere to the surface thereof. Therefore, by selecting the mixing conditions, the composite particles (A) The particle size can be adjusted relatively freely. The composite particles (A) having a circularity of 0.95 or more obtained by such mixing and spheronization steps are substantially those whose surfaces are substantially covered with inorganic fine particles (A-2). For example, in the case of composite particles formed by recombination of wear powder, inorganic fine particles are also present inside the composite particles.

  In addition, when a solid polymer particle (A-1) having a high molecular weight and a strong viscoelasticity is used, it is generally difficult to stably refine the particle. However, in the above embodiment, the inorganic fine particle (A-2) is used. Since they are mixed, the composite particles (A) obtained by the action can be easily and stably miniaturized so that the volume average particle diameter is 2 to 8 μm. Therefore, the composite particles (A) of the present invention can be stably produced by a simple operation.

  At this time, it is preferable to mix the inorganic fine particles (A-2) in the range of 0.5 to 50 parts by mass with respect to 100 parts by mass of the solid polymer particles (A-1), and 2 to 20 parts by mass. It is more preferable to set the range. By mixing in such a range, inorganic fine particles can be dispersed on the surface of the solid polymer particles (A-1).

  The composite particles (A) having a sphericity of 0.95 or more thus obtained are adjusted to a desired particle size through a classification step and added to the printing ink. When adding, it can be added directly to the printing ink, or premixed in the printing ink vehicle in advance to form a paste, and this paste can be added to the ink in the ink manufacturing process. Even if it adds by any method, a favorable result can be obtained. The printing ink can be added to the composite particles by a kneader, a roll mill, a bead mill or the like.

Examples of the present invention will be described below.
In each example, the composite particles (A) having a sphericity of 0.95 or more added to the printing ink are simply referred to as composite particles.

Example 1
Ink 1 was prepared by blending 1.5 parts by mass of the following composite particles A with 100 parts by mass of printing ink for heat-drying type offset rotary press (hereinafter referred to as heat-drying type ink) and then mixing with a three-roll mill. did.
Composite particle A: 100 parts by mass of polyethylene oxide particles having a melting point of 135 ° C. and an acid value of 30 and containing 10 parts by mass of silica powder having a primary average particle size of 10 nm. The composite particles A have a sphericity of 0.97, an average particle size of 5 μm, and 10% by volume of particles having a particle size of 10 μm or more.

(Example 2)
After mixing 1.5 parts by mass of the following composite particle B with respect to 100 parts by mass of the heat-drying ink, ink 2 was prepared by mixing with a three-roll mill.
Composite particle B: 100 parts by mass of polyethylene particles having a melting point of 130 ° C. and 30 parts by mass of silica powder having a primary average particle size of 10 nm. The composite particles B have a sphericity of 0.95, an average particle size of 3 μm, and 5% by volume of particles having a particle size of 10 μm or more.

(Example 3)
Ink 3 was prepared by blending 1.5 parts by mass of the following composite particles C with 100 parts by mass of the heat-drying ink and then mixing with a three-roll mill.
Composite particle C: 100 mass parts of amide wax particles having a melting point of 135 ° C. coated with 30 mass parts of silica powder having a primary average particle diameter of 10 nm. The composite particles C have a sphericity of 0.95, an average particle size of 5 μm, and 5% by volume of particles having a particle size of 10 μm or more.

Example 4
After mixing 1.5 parts by mass of the composite particles D with respect to 100 parts by mass of the heat-drying ink, the ink 4 was prepared by mixing with a three-roll mill.
Composite particle D: After mixing 70 parts by mass of polytetrafluoroethylene particles having a melting point of 310 ° C. and 30 parts by mass of oxidized PE WAX having a melting point of 120 ° C., the mixture is heated to a temperature higher than the melting point of oxidized PE WAX and spheronized by a spheronizer. One containing 20 parts by mass of silica powder having a particle size of 10 nm. This composite particle D has a sphericity of 0.95, an average particle size of 4 μm, and 5% by volume of particles having a particle size of 10 μm or more.

(Example 5)
Ink 5 was prepared by blending 1.5 parts by mass of the following true spherical composite particles E with respect to 100 parts by weight of the heat-drying ink and then mixing with a three-roll mill.
Composite particle E: 10 parts by mass of talc powder having a primary particle diameter of 500 nm per 100 parts by mass of polyethylene particles having a melting point of 125 ° C. The composite particles E have a sphericity of 0.96, an average particle size of 5 μm, and 4% by volume of particles having a particle size of 10 μm or more.

(Example 6)
After blending 1.5 parts by mass of the following composite particles F with respect to 100 parts by mass of room temperature dry offset sheet-fed printing ink (hereinafter, room temperature dry ink), ink 6 was prepared by mixing with a three roll mill. .
Composite particle F: 20 parts by mass of alumina powder having a primary particle size of 10 nm and 10 masses of bentonite powder having a primary particle size of 1000 nm in an oxidized polyethylene particle having a melting point of 120 ° C. and an acid value of 30 and a penetration of less than 1.0 at 25 ° C. Part contained. The composite particles F have a sphericity of 0.95, an average particle size of 8 μm, and 20% by volume of particles having a particle size of 10 μm or more. “Penetration” is the unit depth of 10 ⁻¹ mm, which is the depth at which a needle applied with a weight of 100 g in accordance with JIS K-2235-5.4 enters the sample film at 25 ° C. for 5 seconds. It is expressed as

(Example 7)
Next, 1.5 parts by mass of the following composite particles G were added to 100 parts by mass of the room temperature dry ink, and then mixed with a three-roll mill to prepare a printing ink composition 7.
Composite particles G: 100 parts by mass of polytetrafluoroethylene particles having a melting point of 310 ° C. coated with 5 parts by mass of fatty acid-treated calcium carbonate powder having a primary particle size of 80 nm. The composite particles G have a sphericity of 0.95, an average particle size of 4 μm, and 6% by volume of particles having a particle size of 10 μm or more.

(Example 8)
Next, 1.5 parts by mass of the following composite particles H were added to 100 parts by mass of the room temperature dry ink, and then mixed with a three-roll mill to prepare a printing ink composition 8.
Composite particle H: 10 parts by mass of silica powder having a primary average particle size of 10 nm and 5 parts by mass of quaternary ammonium salt of montmorillonite with 100 parts by mass of Fisher-Tropsch Wax (manufactured by Sazol Wax) having a melting point of 105 ° C. The part is covered. The composite particles H have a sphericity of 0.97, an average particle size of 7 μm, and 20% by volume of particles having a particle size of 10 μm or more.

Example 9
Next, 1.5 parts by mass of the following composite particles I were blended with 100 parts by mass of the room temperature dry ink, and then mixed with a three-roll mill to prepare a printing ink composition 9.
Composite particles I: 100 parts by mass of polyethylene particles having a melting point of 125 ° C. coated with 10 parts by mass of rosin acid-treated calcium carbonate having a primary particle size of 50 nm. The composite particles I have a sphericity of 0.96, an average particle size of 9 μm, and 20% by mass of particles having a particle size of 10 μm or more.

(Example 10)
Next, 1.5 parts by mass of the following composite particles J were added to 100 parts by mass of the ultraviolet curable offset sheet-fed ink, and then mixed with a three-roll mill to prepare a printing ink composition 10.
Composite particle J: 100 parts by mass of polytetrafluoroethylene particles having a melting point of 310 ° C. coated with 10 parts by mass of silica powder having a primary particle size of 10 nm. The composite particles J have a sphericity of 0.95, an average particle size of 5 μm, and 7% by volume of particles having a particle size of 10 μm or more.

(Example 11)
After blending 0.7 parts by mass of each of the following composite particles K and the composite particles A of Example 1 with 100 parts by mass of a room temperature dry aqueous gravure ink, the mixture was mixed with a three-roll mill to obtain an ink composition 11 Was made.
Composite particles K: 100 parts by mass of polypropylene particles having a melting point of 135 ° C. and 30 parts by mass of silica powder having a primary particle size of 10 nm. The composite particles K have a sphericity of 0.95, an average particle size of 5 μm, and 3% by volume of particles having a particle size of 10 μm or more.

(Example 12)
After blending 1 part by mass of each of the following composite particles L and composite particles A of Example 1 with respect to 100 parts by mass of the evaporative drying type solvent gravure ink, they were mixed by a bead mill to produce a printing ink composition 12. .
Composite particles L: 100 parts by mass of an ethylene-vinyl acetate copolymer wax having a melting point of 102 ° C. coated with 30 parts by mass of silica powder having a primary particle size of 10 nm. The composite particles L have a sphericity of 0.96, an average particle size of 6 μm, and 18% by volume of particles having a particle size of 10 μm or more.

(Comparative Example 1)
Next, 1.5 parts by mass of the following particles M were blended with 100 parts by mass of the heat-drying ink, and then mixed with a three-roll mill to prepare a printing ink composition 13.
Particle M: Melting point 130 ° C., sphericity 0.91, average particle size 6 μm, and 15% by volume of particles having a particle size of 10 μm or more.

(Comparative Example 2)
Next, 1.5 parts by mass of the following particles N were added to 100 parts by mass of the heat-drying ink, and then mixed with a three-roll mill to prepare a printing ink composition 14.
Particle N: Melting point of 110 ° C., sphericity of 0.85, average particle size of 7 μm, and 20% by volume of particles having a particle size of 10 μm or more.

(Comparative Example 3)
Next, 1.5 parts by mass of the following particles P were added to 100 parts by mass of the heat-drying ink, and then mixed by a three-roll mill to prepare a printing ink composition 15.
Particle P: Contains 10% by volume of particles having a melting point of 130 ° C., an average particle size of 6 μm, a sphericity of 0.91, and a particle size of 10 μm or more.

(Comparative Example 4)
After mixing 1.5 parts by mass of the following particles Q with respect to 100 parts by mass of the room temperature dry ink, a printing ink composition 16 was prepared by mixing with a three-roll mill.
Particle Q: Polyethylene particles having a melting point of 120 ° C. and having a sphericity of 0.90, an average particle diameter of 5 μm, and containing 10% by volume of particles having a particle diameter of 10 μm or more.

(Comparative Example 5)
Next, 1.5 parts by mass of the following composite particles R were added to 100 parts by mass of the room temperature dry ink, and then mixed with a three-roll mill to prepare a printing ink composition 14.
Composite particles R: 100 parts by mass of polyethylene particles having a melting point of 120 ° C. and 10 parts by mass of silica powder having a primary average particle size of 12 nm. This composite particle N has a sphericity of 0.85, an average particle diameter of 6 μm, and 20% by volume of particles having a particle diameter of 10 μm or more.

(Comparative Example 6)
Next, 1.5 parts by mass of the following true spherical particles S were added to 100 parts by mass of the room temperature dry ink, and then mixed with a three-roll mill to prepare a printing ink composition 15.
Particle S: Polyethylene particles having a melting point of 130 ° C., a sphericity of 0.95, an average particle size of 8 μm, and 23% by volume of particles having a particle size of 10 μm or more.

(Comparative Example 7)
Next, 1.5 parts by mass of the following composite particles T were blended with 100 parts by mass of the room temperature dry ink, and then mixed with a three-roll mill to prepare a printing ink composition 16.
Composite particle T: 100 parts by mass of Fischer-Tropsch wax having a melting point of 105 ° C. coated with 10 parts by mass of silica powder having a primary average particle size of 10 nm and 10 parts by mass of quaternary ammonium salt of montmorillonite. The sphericity is 0.93, the average particle size is 8 μm, and 22% by volume of particles having a particle size of 10 μm or more is contained.

(Comparative Example 8)
Next, 2 parts by mass of the following particles U were blended with 100 parts by mass of the ultraviolet curable offset sheet-fed ink, and then mixed with a three-roll mill to prepare a printing ink composition 17.
Particle U: Polytetrafluoroethylene particles having a melting point of 310 ° C., a sphericity of 0.86, an average particle diameter of 3 μm, and 1% by volume of particles having a particle diameter of 10 μm or more.

(Comparative Example 9)
After blending 1.5 parts by mass of the following particles W with respect to 100 parts by mass of the evaporation-drying solvent gravure ink, a printing ink composition 18 was prepared by mixing with a bead mill.
Particle W: Polyethylene particles having a melting point of 120 ° C., a sphericity of 0.92, an average particle size of 10 μm, and 22% by volume of particles having a particle size of 10 μm or more.

  The inks obtained in each of the examples and comparative examples were tested by printing them on paper with a normal temperature drying system and an ultraviolet curing system of a web offset printing press or a gravure printing machine. The test results are shown in Table 1.

Printing ink for evaluation:
In the above-mentioned examples and comparative examples, the printing ink before mixing the spherical composite particles and the like includes base inks for various performance evaluations of rotary offset lithographic plates (red ink, indigo ink) and bases for various performance evaluations of offset sheet flat plates. Ink (red ink, indigo ink), offset sheet-fed lithographic UV, various base inks for performance evaluation (red ink, indigo ink) and gravure performance base inks (red ink, indigo ink) were used.

Printing conditions:
Printing was carried out with the offset sheet-fed lithographic printing machine described below (also used as a printing test machine for lithographic printing ink for offset-off wheels), and printing suitability (evaluation of piling) and printed matter evaluation were performed. The sheet-fed ink composition was stacked after printing, and dried at room temperature to obtain a printed product evaluation piece. The blocking evaluation is as described below. The UV dry ink composition was used as a printed product evaluation piece by the following UV irradiation machine after printing. Only the ink composition for sheet-fed was evaluated for pressure-resistant barrel stain evaluation. In the heat-drying of the ink for the off-wheel, the printed matter was taken out immediately after printing and was used as a printed matter evaluation piece by a heating and drying apparatus (

・ Kikuhan 4 color offset printing machine (Sakurai Graphic Systems Co., Ltd., CTP version: SCREEN PT-R4300, printing speed: 10,000 sheets / hr)
・ UV irradiation machine (for UV ink): TUJ-690 (Toho Seiki Co., Ltd.)
・ Drying device (off-wheel printing drying device: device name PM-9000D SMT (manufactured by SMT))
Test conditions:
・ Hot air temperature 200 ℃, paper surface temperature 120 ℃
-During blocking evaluation (paper surface temperature 100 ° C)

  About the ink composition obtained by each Example and the comparative example, it printed with the offset printing machine or the gravure printing machine, and performed printing appropriateness evaluation and printed matter evaluation. The test results are shown in Table 1.

The test results in the table are the results evaluated by the following methods, respectively.
Anti-pilling resistance:
After printing 3000 sheets each with the oxidation polymerization type sheet printing ink composition, the heat-drying type off-wheel ink and the UV curable drying ink on an offset printing machine, the plate, blanket and inking for each printing Evaluation is based on the presence of deposits on the roll surface and the degree of contamination. In other words, the solid polymer precipitation was not observed at all, and the printing surface maintained the same image quality as in the initial printing was marked with ◯, and the solid polymer was precipitated and the printing surface was deteriorated. The middle was △.
In the case of gravure printing, a solid polymer is not deposited on the cylinder made at the time of printing with a gravure printing machine, and the printing surface maintains the same image quality as the initial printing. The case where the molecules were precipitated and the printed surface was deteriorated was marked with “x”, and the middle was marked with “Δ”.

Pressure-resistant barrel stain resistance (evaluated for sheet-fed printing ink composition):
After 3000 sheets are printed on an offset sheet-fed lithographic printing press, they are stacked and left for a day, then turned over and printed on the back side, and how much preprinted printing ink adheres to the metal impression cylinder. Judge visually. Good ones with almost no impression cylinder dirt were marked with ◎, those with little dirt but no problem were marked with ◯, those with slight dirt were marked with △, and those with severe dirt were marked with x.

Blocking resistance:
Immediately after printing the printed material of the printing ink composition for a sheet, the printed surfaces are stacked and left at a load of 500 g / cm ² at a room temperature of 40 ° C. and a humidity of 60% for 24 hours. Was visually evaluated. The case where there was no set-off was rated as ◎, the case where almost no set-off was observed was marked as ○, the case where a slight amount was seen was marked as Δ, and the case where a lot of set-out was seen was marked as x.
Regarding the evaluation of the off-wheel ink composition, after printing, hot air of 200 ° C. is blown to make the printed material semi-dry so that the paper surface temperature becomes 100 ° C., and immediately after that, the printed surfaces are overlapped and the printed material of the sheet-fed ink composition is printed. Evaluation was performed under the same conditions as above.

Abrasion resistance of printed materials:
The room temperature dry ink composition was printed on special art paper, dried for 24 hours, and then rubbed with a Toyo Seiki Gakushin friction tester under a load of 500 g under 20 reciprocating conditions. The degree of deterioration was evaluated in five stages. A good one with almost no rubbing dirt was designated as ◎, a slight rubbing dirt was indicated as ◯, a slight rubbing dirt was indicated as △, a slight rubbing dirt was indicated as x, and a rubbing dirt was marked as xx.
For the evaluation of the off-ring ink composition, after printing on pearl-coated paper using a sheet-fed printing machine as an evaluation printing machine, blow hot air of 200 ° C. so that the paper surface temperature becomes 120 ° C., and then cool the paper surface to room temperature. As an evaluation piece, the abrasion resistance was evaluated in five stages in the same manner as the room temperature dry ink.
The UV ink composition is printed on a carton, and the printed matter is rubbed with a UV irradiation device under a load of 500 g and 500 reciprocations, and the degree of image degradation due to wear is similarly evaluated in five levels. did.

Gloss evaluation of printed materials:
Measured by the ratio (%) of incident light intensity at an incident angle of 60 degrees and reflected light intensity at a reflection angle of 60 degrees on a solid print surface after drying [Gloss meter: GM-3D, manufactured by Murakami Color Research Laboratory Co., Ltd. Then, referring to this result, it was comprehensively evaluated whether or not the printed matter had a high gloss by visual evaluation.
Those with high gloss and good printed matter were marked with ◎, slightly good with ○, slightly inferior with Δ, and inferior with ×.

  In addition, the detailed composition of the printing ink used by the above-mentioned Example and comparative example is as follows.

  The base ink for various performance evaluations of the offset rotary lithographic plate has the following constitution, and the rosin-modified phenolic resin varnish used is obtained by the following constitution.

  (Red ink) Carmine 6B (product name: ECR101, Dainichi Seika Kogyo Co., Ltd.) 8-22% by mass, rosin-modified phenolic resin varnish 60-70% by mass, AF-solvent 7 (trade name, Nippon Oil Corporation ) Solvent) 10-20% by mass, other additives 5-10% by mass. With this formulation, the particle size was measured with a bead mill and 3 rolls using a grind gauge: manufactured by Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000), and dispersed until a particle size of 5.0 μm or less was obtained. The final adjustment is to adjust the tackiness: tack value (Incometer measuring instrument Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.2 2000 according to JIS K 5701 4.2 2000) to 4-7, and the ink Fluidity: Adjusted to 38 to 42 mm at a flow value (spread meter measuring instrument, manufactured by Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.1 2000, 25 ° C., 1 minute diameter value).

  (Indigo ink) Phthalocyanine blue (product name: ECB-303, Dainichi Seika Kogyo Co., Ltd.) 18-22% by mass, rosin-modified phenolic resin varnish 60-70% by mass, AF-solvent 7 (trade name, Nippon Oil (Solvent Co., Ltd.) 10-20% by mass, other additives 5-10% by mass. With this formulation, the particle size was measured with a bead mill and 3 rolls using a grind gauge: manufactured by Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000), and dispersed until a particle size of 5.0 μm or less was obtained. The final adjustment is to adjust the tack: tack value (Incometer measuring instrument Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.2 2000 according to JIS K 5701 4.2 2000) to 4-7, and the ink Fluidity: Adjusted to 38 to 42 mm at a flow value (spread meter measuring instrument, manufactured by Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.1 2000, 25 ° C., 1 minute diameter value).

  Formulation of rosin-modified phenolic resin varnish: Tamanol 420 (product name, Arakawa Chemical Industries, Ltd.) 35-45% by mass, alkyd resin HL-17 (trade name, Toshin Oil & Fats (product)) 1-5% by mass, soybean White drawn oil (Nisshin Oil (manufactured)) 1-10% by mass, TX-100 (Nab Corporation (manufactured)) 10-20% by mass, AF-solvent No. 4 (trade name, Nippon Oil Corporation solvent) ) 35 to 45% by mass, ALCH (trade name: Kawaken Fine Chemical Co., Ltd.) 0.5 to 2% by mass is heated and mixed at 180 ° C. to 220 ° C. to dissolve the resin, and the viscosity is 25 in terms of cone and plate type viscosity. The viscosity is adjusted to 30 to 40 Pa · s at a shear rate of 100 / s at ℃ to make a varnish.

  The base ink for various performance evaluations of offset sheet lithographic plates has the following constitution, and the rosin-modified phenolic resin varnish used is obtained by the following constitution.

  (Red ink) Carmine 6B (Product name: ECR101, Dainichi Seika Kogyo Co., Ltd.) 8-22% by mass, 60-70% by mass of rosin-modified phenolic resin varnish, AF-Solvent 6 (trade name, Nippon Oil Co., Ltd. ) Solvent) 5 to 10% by weight, cobalt and manganese composite drying accelerator 1% by weight (trade name: Petro Dryer EF, T & K TOKA (manufactured)), and other additives 5 to 10% by weight. With this formulation, the particle size was measured with a bead mill and 3 rolls using a grind gauge: manufactured by Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000), and dispersed until a particle size of 5.0 μm or less was obtained. The final adjustment is to adjust the tackiness: tack value (Incometer measuring instrument Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.2 2000, 32 ° C., value after 1 minute) to 6-9, and Fluidity: Adjusted to 37 to 40 mm at a flow value (spread meter measuring device, manufactured by Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.1 2000, 25 ° C., 1 minute diameter value).

  (Indigo ink) Phthalocyanine blue (product name: ECB-303, Dainichi Seika Kogyo Co., Ltd.) 18-22% by mass, rosin-modified phenolic resin varnish 60-70% by mass, AF-solvent 6 (trade name, Nippon Oil (Solvent Co., Ltd.) 5-10% by mass, cobalt, manganese composite drying accelerator 1% by mass (trade name: Petro Dryer EF, T & K TOKA (manufactured)), and other additives 5-10% by mass. With this formulation, the particle size was measured with a bead mill and 3 rolls using a grind gauge: manufactured by Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000), and dispersed until a particle size of 5.0 μm or less was obtained. The final adjustment is to adjust the tackiness: tack value (Incometer measuring instrument Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.2 2000, 32 ° C., value after 1 minute) to 6-9, and Fluidity: Adjusted to 37 to 40 mm at a flow value (spread meter measuring device, manufactured by Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.1 2000, 25 ° C., 1 minute diameter value).

  Formulation of rosin-modified phenolic resin varnish: Tamanol 463 (product name, Arakawa Chemical Industries, Ltd.) 30 to 40% by mass, alkyd resin HL-17 (trade name, Toshin Oil and Fats (product)) 1 to 5% by mass, soybean White squeezed oil (Nisshin Oil (manufactured)) 25-35% by mass, soybean oil fatty acid N-butyl ester SFB-2 (trade name, Toshin Yushi (manufactured)) 10-20% by mass, AF-solvent No. 5 ( Trade name, Nippon Petroleum Co., Ltd. solvent) 15-25% by mass, Octopu Aluminum T (trade name, Hope Pharmaceutical Co., Ltd.) 0.5-1% by mass at 180 ° C. to 230 ° C. and mixed. The viscosity is adjusted to a viscosity of 35 to 40 Pa · s at a shear rate of 100 / s at 25 ° C. with a cone-and-plate type viscosity to obtain a varnish.

  The base inks (red ink and indigo ink) for evaluating various performances of offset sheet-fed planographic UV used the following compositions.

  (Red ink) Carmine 6B (Product name: ECR101, Dainichi Seika Kogyo Co., Ltd.) 20-25% by mass, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (Product name: KAYARAD DPHA, Nippon Kayaku Co., Ltd.) Company (product) 20-30% by mass, bisphenol A diglycidyl ether diacrylate (trade name: CN121, Arkema (product)) 20-30% by mass, ditrimethylolpropane tetraacrylate (product name: KAYARAD T-1420 (T ), Arkema (manufactured)) 5-10% by mass, photopolymerization initiator: 2-methyl-1- [4- (methylthio)]-2-monoforinopropan-1-one (product names: IRUGACURE907, BASF ( Manufactured)) 5-10% by mass, other additives 1-10% by mass Become. With this formulation, the particle size was measured with a bead mill and 3 rolls using a grind gauge: manufactured by Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000), and dispersed until a particle size of 5.0 μm or less was obtained. The final adjustment is to adjust the tackiness: tack value (Incometer measuring instrument, Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.2 2000, 32 ° C., value after 1 minute) to 5-8, and ink The flowability was adjusted to 35 to 38 mm with a flow value (spread meter measuring instrument, manufactured by Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.1 2000, diameter value after 1 minute at 25 ° C.).

  (Indigo ink) Phthalocyanine blue (Product name: ECB-303, Dainichi Seika Kogyo Co., Ltd.) 20 to 25% by mass, mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (Product name: KAYARAD DPHA, Nippon Kayaku) Yakuhin Co., Ltd. (produced)) 20-30% by mass Bisphenol A diglycidyl ether diacrylate (product name: CN121, Arkema (produced)) 20-30% by mass, ditrimethylolpropane tetraacrylate (product name: KAYARAD T-1420 ( T), Arkema (manufactured)) 5 to 10% by mass, photopolymerization initiator: 2-methyl-1- [4- (methylthio)]-2-monoforinopropan-1-one (product name: IRUGACURE907: BASF) (Manufactured)) 5-10 mass%, other additives 1-10 quality Consists of% by volume. With this formulation, the particle size was measured with a bead mill and 3 rolls using a grind gauge: manufactured by Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000), and dispersed until a particle size of 5.0 μm or less was obtained. Final adjustment is tack: tack value (Incometer measuring instrument, Toyo Seiki Seisakusho (manufactured): according to JIS K 5701 4.2 2000, 32 ° C., value after 1 minute) adjusted to 5-8, and ink The flowability was adjusted to 35 to 38 mm with a flow value (spread meter measuring instrument, manufactured by Toyo Seiki Seisakusho (manufactured): JIS K 5701 4.1 2000, diameter value after 1 minute at 25 ° C.).

Base ink for evaluation of various gravure performances (red ink)
Lake Red C # 405 (F) (product name, Dainichi Seika Kogyo Co., Ltd.) 10 to 20% by mass, nitrified cotton dope (trade name: Nitron NC Dope No. 5, Taisei Kako Co., Ltd.) 20 -40% by weight, Imahama 99% IPA-modified ethanol (product name, Imazu Pharmaceutical Co., Ltd.) 15-25% by weight, ethyl acetate 15-25% by weight, isopropyl alcohol 10-20% by weight, other additives 1 It consists of 10% by mass.
With this formulation, the pigment was dispersed with a bead mill until the particle size was measured with a grind gauge: Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000) to a particle size of 20 μm or less. Zaan Cup No. 3 (trade name, Koiso Co., Ltd.) (based on viscosity measurement method using JIS K 5600-2-2 flow cup) and added after the above solvent combination so as to be 15 to 20 seconds. Adjusted.

Base ink for various gravure performance evaluation (indigo ink)
10-20% by mass of indigo pigment of phthalocyanine blue (product name: ECB-303, Dainichi Seika Kogyo) (product name: Nitron NC Dope No. 5, Taisei Kako (product)) 20-40 % By weight, Imahama 99% IPA-modified ethanol (trade name, Imazu Pharmaceutical Co., Ltd.) 15-25% by weight, ethyl acetate 15-25% by weight, isopropyl alcohol 10-20% by weight, other additives 1-10% by weight %.

  With this formulation, the pigment was dispersed with a bead mill until the particle size was measured with a grind gauge: Toyo Seiki Seisakusho (based on JIS K 5701 4.3 2000) to a particle size of 20 μm or less. Zaan Cup No. The viscosity was adjusted by post-adding with a combination of the above solvents so as to be 15 to 20 seconds (according to the viscosity measurement method using a flow cup of JIS K 5600-2-2) by 3 .

  As described above, the printing ink composition of the present invention can improve the peeling and printing plate residue at the time of printing, becomes an excellent printed material with improved abrasion resistance of the printed surface at the time of printing and after printing, and effectively prevents the blocking phenomenon. It was found that it was possible to suppress the impression cylinder stains and to obtain a highly glossy printed matter.

  The present invention is suitable as various printing ink compositions, particularly as heat-set rotary presses for offset lithographic printing presses and sheet-fed printing inks.

Claims (5)

A printing ink composition containing the composite particles (A) in the printing ink,
The composite particles (A) are solid polymer particles (A-1) made of a resin, wax or a mixture thereof that does not dissolve in printing ink, and inorganic fine particles (A- 2) The volume average particle size of the composite particles (A) is in the range of 2 to 8 μm, the volume content of the particles having a particle size exceeding 10 μm is 20% by volume or less, and the composite A printing ink composition, wherein the sphericity of the particles (A) is 0.95 or more.   The composite particles (A) contain the inorganic fine particles (A-2) in a range of 0.5 to 50 parts by mass with respect to 100 parts by mass of the solid polymer particles (A-1). The printing ink composition according to claim 1, wherein the fine particles (A-2) are formed so as to cover the surface of the solid polymer particles (A-1).   The said inorganic fine particle (A-2) consists of 1 type of a metal oxide, a metal nitride, a metal carbide, a metal sulfate, sulfide, and fluoride, or these mixtures. Printing ink composition. The solid polymer particle (A-1) has a melting point of 120 ° C. or higher, and a needle loaded with 100 g according to JIS K-2235-5.4 is in the sample film at 25 ° C. for 5 seconds. The printing ink composition according to any one of claims 1 to 3, which is a wax having a penetration of 2.0 or less expressed in units of 10 ^-1 mm.   The printing according to any one of claims 1 to 4, wherein the solid polymer particles (A-1) are oxidized polyethylene waxes having a melting point of 120 ° C or higher and an acid value of 10 or higher. Ink composition.

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