JP2021008594A - Liquid print ink, printed matter, and laminate - Google Patents

Abstract

To provide a liquid print ink that is excellent in adhesiveness to various packaging materials, laminate strength, and blocking resistance after film printing, and prevents the phenomenon of plate fogging from occurring in gravure printing, and is excellent in concealability, adhesiveness to a film substrate, blocking resistance, and laminate suitability.SOLUTION: A liquid print ink contains a binder resin, an organic solvent, and a colorant, the liquid print ink containing titanium oxide (A) obtained by sulfuric acid method, and an inorganic filler (B).SELECTED DRAWING: None

Description

The present invention relates to a liquid printing ink that can be used as a gravure ink or a flexographic ink.

Liquid printing inks such as gravure inks and flexographic inks are widely used for the purpose of imparting cosmeticity, functionality, and surface protection to an object to be printed. When this printed matter is used as a food packaging material among packaging materials, it is generally laminated. In this case, various printed materials and laminating processes are used depending on the type of contents and the purpose of use.
Conventionally, printing inks using polyurethane resin as a binder have been widely used for such laminated products because they are excellent in adhesiveness to various printed objects, laminating strength of various laminated products, and boil retort suitability. ..

On the other hand, with the diversification of packaging materials in recent years, liquid printing inks are required to have adhesiveness to various packaging materials, lamination strength, and blocking resistance after film printing. Also, in gravure printing, the part other than the image area where the ink cannot be scratched by the doctor becomes "fog" and transfers to the printed matter, "plate fog phenomenon", and the cells of the gravure printing plate are clogged with ink. It is also required to maintain good highlight transferability due to the "plate jam phenomenon" that is difficult to transfer to printed matter, and further improvement is being attempted as an ink that satisfies all of these problems.

Of the liquid printing inks, white ink mainly uses titanium oxide as a pigment, which is an inorganic pigment and has a high content in the ink, and is related to ensuring performance such as adhesion to various packaging materials and lamination strength. Is more difficult than inks that use organic pigments such as indigo ink. Further, since it has a hardness higher than that of an organic pigment, there is a problem that the doctor blade is severely worn when it is used as a gravure ink.

To solve these problems, for example, a composite particle containing titanium oxide particles, barium sulfate particles and / or calcium carbonate particles arranged around the titanium oxide particles, and the composite particles are coated with an aluminum compound. A method of using a composite white pigment for gravure ink, which is larger than the size of one titanium oxide particle and is easily scraped by a doctor blade (see, for example, Patent Document 1), or surface-treated with silica or alumina. A method of improving the printability of a gravure ink by using titanium oxide having a rutile-type crystal structure is known (see, for example, Patent Document 2, paragraph 0059). However, none of these methods have satisfied all of these problems.

WO2013187408A Gazette Japanese Unexamined Patent Publication No. 2019-11435

The problems of the present invention are excellent adhesiveness to various packaging materials, laminating strength, blocking resistance after film printing, less likely to cause plate fog in gravure printing, hiding property, adhesiveness to film substrate, and resistance. An object of the present invention is to provide a liquid printing ink having excellent blocking properties and laminating suitability.

As a result of diligent research to solve the above-mentioned problems, the present inventors are liquid printing inks containing a binder resin, an organic solvent, and a colorant, and the oxidation obtained by the sulfuric acid method as the colorant. It has been found that a liquid printing ink containing titanium (A) and an inorganic filler (B) solves the above problems.

That is, the present invention is a liquid printing ink containing a binder resin, an organic solvent, and a colorant, and is characterized by containing titanium oxide (A) and an inorganic filler (B) obtained by a sulfuric acid method. Regarding liquid printing ink.

The present invention also relates to a liquid printing ink having a treated layer made of at least alumina and / or silica on the surface of the titanium oxide (A).

The present invention also relates to a liquid printing ink in which the Mohs hardness of the inorganic filler (B) is 1 to 5.

The present invention also relates to a liquid printing ink in which the inorganic filler (B) is a clay mineral.

The present invention also relates to a liquid printing ink in which the mass ratio of the titanium oxide (A) to the inorganic filler (B) is 99: 1 to 1:99.

The present invention also relates to a liquid printing ink in which the binder resin is a polyurethane urea resin having a weight average molecular weight of 15,000 to 100,000 and a urethane bond concentration of 1.2 mmol / g or more and 2.5 mmol / g or less. ..

The present invention also relates to a printed matter having a printed layer formed by printing the liquid printing ink on a substrate.

The present invention also relates to a laminate in which an adhesive layer and a film layer are laminated in this order on the printed layer of the printed matter.

According to the present invention, it is excellent in adhesiveness to various packaging materials, laminating strength, blocking resistance after film printing, less likely to cause plate fog in gravure printing, hiding property, adhesiveness to film substrate, and blocking resistance. , And a liquid printing ink having excellent laminating suitability can be obtained.

(Definition of words)
In the present invention, the liquid printing ink refers to a liquid ink applied to a printing method using a printing plate, such as a gravure ink or a flexo ink, and is preferably a gravure ink or a flexo ink. Further, the liquid printing ink of the present invention does not contain an active energy curable component, that is, is a liquid ink that is non-reactive with active energy rays.
The "inks" used in the following description all refer to "printing inks". Moreover, all "parts" indicate "mass parts".

The liquid printing ink of the present invention is a white printing ink containing titanium oxide (A) and an inorganic filler (B) obtained by a sulfuric acid method as a white colorant.

(Titanium oxide (A))
As the titanium oxide used in the present invention, known titanium oxide can be used without any particular limitation on the production method, shape, crystal shape and particle size. For example, the titanium oxide particles may be produced by a chlorine method or a sulfuric acid method. Those manufactured by the sulfuric acid method are preferable in terms of suppressing wear of the doctor blade.

An example of a specific embodiment of the titanium oxide manufacturing process by the sulfuric acid method is as follows.
(1) Dissolution step: The dried and crushed ilmenite ore is dissolved with sulfuric acid to prepare a solution mainly of titanium sulfate (TIOSO ₄ ) and ferrous sulfate (FeSO ₄ ).
(2) cooling, separating step: obtaining a stock solution by cooling the dissolved dope crystallized out ferrous sulfate _(FeSO 4 · _7H 2 O) was separated by a centrifuge.
(3) Hydrolysis step: The undiluted solution from which ferrous sulfate has been separated is heated to separate it into titanium hydroxide (TiO (OH) ₂ ) and sulfuric acid.
(4) Firing step: The white precipitate of titanium hydroxide obtained by the hydrolysis reaction is thoroughly washed with water, filtered, and then calcined at 900 ° C. or higher to have a predetermined particle size of rutile-type titanium oxide (TiO ₂ ). And.

The crystal form of the titanium oxide particles may be rutile type, anatas type or brookite type. The rutile type is preferable in that a higher hiding rate can be obtained. The average particle size of the titanium oxide particles is preferably 0.1 to 1.0 μm, more preferably 0.1 to 0.5 μm, still more preferably 0.2 to 0, from the viewpoint of exhibiting high glossiness and hiding ratio. .3 μm. If the average particle size of the titanium oxide particles is less than 0.1 μm, the hiding rate is lowered, and the doctor blade is likely to leave scratches, which is likely to cause plate fog. Further, if the average particle size of the titanium oxide particles exceeds 1.0 μm, the hiding rate and glossiness may decrease.

The titanium oxide (A) preferably has a treated layer made of at least alumina and / or silica on its surface.
In titanium oxide surface-treated with alumina and / or silica, silica is generally used for the purpose of adjusting the state of acids and bases on the surface of titanium oxide and for imparting the durability of the obtained ink / paint film. , Alumina is used to improve the wetting of titanium oxide during dispersion. Examples of the surface treatment method for titanium oxide include water-based treatment and vapor phase treatment. From the viewpoint of dispersion stability, the ratio of the treated amount of silica to alumina is preferably 35% by mass or more and 80% by mass or less. The amount of the inorganic substance with respect to titanium oxide is not necessarily limited, but is generally 30 parts or less with respect to 100 parts of titanium oxide.

As the titanium oxide surface-treated with silica and alumina, a commercially available product may be used, and for example, it is commercially available from a titanium oxide manufacturer such as Ishihara Sangyo Co., Ltd. or Tayca Corporation. For example, varieties with a large amount of silica treated compared to the amount treated with alumina and varieties with a large amount of treated alumina compared to the amount treated with silica are commercially available, and titanium oxide whose amount treated with alumina falls within the above ratio range is also available. Can be done.

The mass ratio of each of the alumina and silica can be estimated from the amount of alumina and silica present together with titanium oxide on the surface of titanium oxide. The abundance ratio of alumina and silica can be confirmed by analyzing and comparing the amounts of alumina or silica adsorbed on the surface of titanium oxide by fluorescent X-rays, ESCA or the like. In particular, measurement by fluorescent X-ray is simple and highly accurate. In addition to being present on the surface of titanium oxide, silica and alumina may be partially present as free particles, and the total amount can be measured by measuring with fluorescent X-rays. As for the quantification method using fluorescent X-rays, an analysis method using a calibration curve using standard materials has been established.
Therefore, the mass ratio of alumina and silica present on the surface of commercially available titanium oxide can be confirmed by measurement with fluorescent X-rays, and titanium oxide having various mass ratios can be used.

(Inorganic filler (B))
The inorganic filler (B) used in the present invention is not particularly limited, and is, for example, oxide-based ceramics such as alumina, silica, zirconia, magnesia, ceria, itria, zinc oxide, and iron oxide; silicon nitride, titanium nitride, boron nitride. Nitride ceramics such as silicon carbide, calcium carbonate, magnesium sulfate, aluminum sulfate, aluminum hydroxide, aluminum hydroxide, potassium titanate, talc, kaolinite, dikite, nacrite, halloysite, pyrophyllite, montmorillonite, seri Ceramics such as sight, mica, amesite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate, diatomaceous earth, and silica sand; glass fibers and the like can be mentioned. These may be used alone or in combination of two or more.

Among these, clay minerals such as kaolinite, halloysite, and montmorillonite are preferable, and kaolin (natural hydrous aluminum silicate) made from these clay minerals, for example, kaolinite (kaolin mineral) is also used. It can be preferably used. As kaolin, wet kaolin and calcined kaolin obtained by calcining the wet kaolin are known. In this embodiment, unfired kaolin is particularly preferred.

The inorganic filler (B) preferably has an appropriate hardness, and specifically, the Mohs hardness is preferably in the range of 1 to 5. More preferably, it has a Mohs hardness of 1-3.

The average particle size of the inorganic filler is preferably more than 0.01 μm and 4.0 μm or less, more preferably more than 0.05 μm and 2.0 μm or less, and more than 0.1 μm and 1.0 μm. The following is more preferable. Adjusting the average particle size of the inorganic filler within the above range means that the particle size of the inorganic filler and its distribution can be adjusted by using an appropriate pulverizer such as a ball mill, a bead mill, or a jet mill. Examples thereof include a method of pulverizing to reduce the particle size.

Examples of the shape of the inorganic filler include plate shape, scale shape, needle shape, columnar shape, spherical shape, polyhedral shape, and lump shape. A plurality of types of inorganic fillers having these shapes may be used in combination.

Generally, the higher the content of the titanium oxide (A) in the liquid printing ink, the higher the hiding power, while the titanium oxide, which is an inorganic pigment, tends to wear the doctor blade and easily cause plate fog. .. However, in the present invention, since titanium oxide (A) and the inorganic filler (B) are used in combination, the phenomenon of plate fogability can be reduced while maintaining high hiding power. The reason for this is not clear, but inorganic fillers can serve as cushioning materials. In that sense, the inorganic filler preferably has a Mohs hardness in the range of 1 to 5 as described above. In addition, kaolin is the most effective inorganic filler that is used in combination with titanium oxide (A) to reduce the phenomenon of plate fog while maintaining high hiding power.

The content of titanium oxide (A) depends on the desired ink performance, but if it is a white ink that requires standard hiding power and high plate fogability, it is usually about 20 to 40% by mass with respect to the total mass of the ink. On the other hand, in the case of white ink for which the required performance is very high concealment, the content is often designed to be about 40 to 60% by mass.
On the other hand, the titanium oxide (A) and the inorganic filler (B) are blended in a mass ratio of 99: 1 to 1:99 to contribute to the plate fogability and concealment property which are the effects of the present invention. The mass ratio is preferably in the range of 99: 1 to 50:50, more preferably in the range of 99: 1 to 80:20.
Since the titanium oxide (A) and the inorganic filler (B) act as a white colorant, they are preferably contained in the range of 20 to 75% by mass in total with respect to the total mass of the ink of the present invention. It is more preferably in the range of 20 to 60% by mass, and most preferably in the range of 30 to 50% by mass. In this range, an ink having a particularly excellent balance between plate fog and concealment can be obtained.

A colorant can be added to the liquid printing ink of the present invention. As the colorant, organic and inorganic pigments and dyes used in general inks, paints, recording agents and the like can be used. Organic pigments include azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine-azo-based, dictopyrrolopyrrole-based, and isoindoline-based. Pigments can be mentioned.

Examples of the inorganic pigment include carbon black, red iron oxide, aluminum, mica (mica) and the like. Further, a brilliant pigment (Metashine; Nippon Sheet Glass Co., Ltd.) in which a metal or a metal oxide is coated on a glass flake or a lump flake as a base material can be used. It is preferable to use carbon black for black ink, aluminum for gold and silver ink, and mica (mica) for pearl ink from the viewpoint of cost and coloring power. Although aluminum is in the form of powder or paste, it is preferably used in the form of paste from the viewpoint of handleability and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and concentration.

(Binder resin)
The binder resin used in the present invention is not particularly limited as long as it is a binder resin used for a liquid ink applied to a printing method using a printing plate, such as gravure ink or flexographic ink, but the present invention. It is preferable to use a polyurethane urea resin as the main binder resin because it is excellent in adhesiveness to a film substrate, blocking resistance, laminating suitability, highlight transfer property, etc., which are problems.

As the binder resin, a polyurethane urea resin having a weight average molecular weight of 15,000 to 100,000 and a urethane bond concentration in the range of 1.2 mmol / g or more and 2.5 mmol / g or less is preferable.
Further, the structural unit derived from the polyether polyol is preferably contained in an amount of 1 to 50% by mass, more preferably 1 to 30% by mass in 100% by mass of the polyurethane urea resin.

The weight average molecular weight of the polyurethane urea resin is a value measured under the following conditions by a gel permeation chromatography (GPC) method.
Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm I.D. x 30 cm) x 1 "TSKgel G4000" (7.8 mm I.D. x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 This "TSKgel G2000" (7.8 mm ID x 30 cm) x 1 Detector: RI (Differential Refractometer)
Column temperature: 40 ° C
Eluent: tetrahydrofuran (THF)
Flow velocity: 1.0 mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

The urethane bond concentration of the urethane urea resin used in the liquid printing ink of the present invention is preferably 1.2 mmol / g or more and 2.5 mmol / g or less, and more preferably 1.3 mmol / g or more. When the urethane bond concentration of the liquid printing ink of the present invention is 1.2 mmol / g or more and 2.5 mmol / g or less, the adhesiveness to the film substrate and the blocking property accompanied by the set-off of the printed pattern are improved. More preferably, it is 3 mmol / g or more.
When the urethane bond concentration is 1.2 mmol / g or more, the polyethylene extrusion lamination strength for the gravure printed matter or the flexographic printed matter using the liquid printing ink of the present invention tends to be sufficiently maintained. On the other hand, if the urethane bond concentration is 2.5 mmol / g or less, in the case of gravure printing, the part where the ink cannot be scraped off by the doctor becomes "fog" in the part other than the image area and is transferred to the printed matter. The phenomenon that "the phenomenon of" occurs can be suppressed.
If the urethane bond concentration of the present invention is 1.2 mmol / g or more and 2.5 mmol / g or less, it may cause problems in gravure printing in addition to adhesiveness to various films and blocking property accompanied by set-off of printed patterns. It also has "fog prevention".
Further, by setting the urethane bond concentration to 2.5 mmol / g or less, it is possible to suppress entanglement stains caused by the ink drying on the plate during long-run printing with a flexographic plate.
The urethane bond concentration can be calculated by the following formula (1).

Urethane bond concentration = {(W1 x OH1 + W2 x OH2 + ... + Wi x OHi) x 1000} / (56100 x S) Expression (1)

In formula (1), they are as follows.
When a plurality of types of polyols are used, they are calculated as polyol 1, polyol 2 to polyol i, respectively.
W1: Mass of polyol 1 OH1: Hydroxyl value of polyol 1 W2: Mass of polyol 2 OH2: Mass of polyol 2 Wi: Mass of polyol i OHi: Hydroxyl value of polyol i S: Mass of urethane resin solid content

Examples of the polyether polyol include polyether polyols of polymers such as ethylene oxide, propylene oxide and tetrahydrofuran, or copolymers. Specifically, known general-purpose products such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol may be used. By using the polyether polyol in the above range, the adhesiveness particularly on the high-performance barrier film is significantly improved, and as a result, the blocking resistance and the lamination strength are excellent. Among the polyether polyols, polyethylene glycol is particularly preferable in order to particularly improve the adhesiveness, blocking resistance and laminate strength on the high-performance barrier film.

The number average molecular weight of the polyether polyol is preferably 100 to 3500. The number average molecular weight of the polyether polyol was measured under the above-mentioned conditions by the gel permeation chromatography (GPC) method as in the case of the polyurethane urea resin.

If the number average molecular weight of the polyether polyol, which is a component of the polyurethane urea resin used in the liquid printing ink of the present invention, is 100 or more, the polyurethane urea resin film does not become hard and can be applied to a film substrate such as a polyester film. Adhesiveness also tends to be retained. When the number average molecular weight is 3500 or less, the blocking resistance of the ink film tends to be maintained without the polyurethane urea resin film becoming brittle.

As the combined polyol used as necessary for the polyurethane urea resin used in the liquid printing ink of the present invention, various known polyols generally used for producing the polyurethane urea resin can be used, and one or two. Seeds or more may be used together. For example, polyether polyols of polymers or copolymers such as methylene oxide, ethylene oxide, tetrahydrofuran (1); ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3. -Propanediol, 2-ethyl-2butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexane Diol, octanediol, 1,4-butinediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1, Saturated or unsaturated low molecular weight polyols (2) such as 2,4-butanetriol, sorbitol, pentaesritol; these low molecular weight polyols (2) and adipic acid, phthalic acid, isophthalic acid, terephthalic acid With polyvalent carboxylic acids such as maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelli acid, speric acid, azelaic acid, sebacic acid, trimellitic acid, pyromellitic acid or their anhydrides. Polyol polyols (3) obtained by dehydration condensation or polymerization of the above; cyclic ester compounds such as polycaprolactone, polyvalerolactone, poly (β-methyl-γ-valerolactone) and other lactones are ring-open polymerized. The obtained polyester polyols (4); the polycarbonate polyols (5) obtained by reacting the low molecular weight polyols (2) and the like with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgen and the like; polybutadiene glycols (6). ); Glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A (7); one or more hydroxyethyl, hydroxypropul acrylate, acrylic hydroxybutyl, etc. in one molecule, or their corresponding methacryl Examples thereof include an acrylic polyol (8) obtained by copolymerizing an acid derivative or the like with acrylic acid, methacrylic acid or an ester thereof.

Among the polyester polyols (3), the high molecular weight diol obtained from the diols (glycols) and the dibasic acid is a low molecule having up to 5 mol% of the diols having three or more hydroxyl groups. It can be replaced with the polyol (2).

Examples of the diisocyanate compound used in the polyurethane urea resin in the liquid printing ink of the present invention include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates generally used in the production of polyurethane urea resins. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzylisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3- Phenylene diisocyanate, 1,4-phenylenediocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexane-1 , 4-Diisocyanate, Xylylene diisocyanate, Isophorone diisocyanate, Dimeryl diisocyanate, Dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, Methylcyclohexanediisocyanate, Norbornan diisocyanate, m-Tetramethylxylylene Examples thereof include isocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanate-benzyl chloride, and dimerized isocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group. These diisocyanate compounds can be used alone or in combination of two or more.

Examples of the chain extender used in the polyurethane urea resin in the liquid printing ink of the present invention include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine and the like. , 2-Hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypyropyl Amines having a hydroxyl group in the molecule such as ethylenediamine, di-2-hydroxypyrropylethylenediamine, and di-2-hydroxypropylethylenediamine can also be used. These chain extenders can be used alone or in admixture of two or more.
In addition, a monovalent active hydrogen compound can also be used as an end-blocking agent for the purpose of stopping the reaction. Examples of such a compound include alkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Further, especially when it is desired to introduce a carboxyl group into a polyurethane resin, amino acids such as glycine and L-alanine can be used as a reaction terminator. These terminal blockers can be used alone or in admixture of two or more.

The polyurethane urea resin used in the liquid printing ink of the present invention is, for example, a prepolymer obtained by reacting polyethylene glycol and a combined polyol with a diisocyanate compound at a ratio of an excess of isocyanate groups to obtain a prepolymer having terminal isocyanate groups. , That is, an ester-based organic solvent such as ethyl acetate, propyl acetate, butyl acetate, which is usually used as a solvent for non-toluene gravure ink or flexo ink; acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Ketone-based solvents; alcohol-based organic solvents such as methanol, ethanol, isopropyl alcohol, n-butanol; hydrocarbon-based solvents such as methylcyclohexane and ethylcyclohexane; or chain extenders and / or mixed solvents thereof. It is produced by a two-step method of reacting with a terminal-blocking agent, or a one-step method of reacting polyethylene glycol and a combined polyol, a diisocyanate compound, a chain extender and / or a terminal-blocking agent at once in a suitable solvent among the above. Among these methods, a two-step method is preferable in order to obtain a uniform polyurethane urea resin. When the polyurethane urea resin is produced by the two-step method, the reaction is carried out so that the total (equivalent ratio) of the amino groups of the chain extender and / or the terminal blocker is 1 / 0.9 to 1.3. It is preferable to let it. When the equivalent ratio of the isocyanate group to the amino group is less than 1 / 1.3, the chain extender and / or the terminal sequestering agent remain unreacted, the polyurethane urea resin turns yellow, or the odor after printing occurs. May occur.

The content of the polyurethane urea resin used in the liquid printing ink of the present invention in the ink is 4% by mass or more with respect to the total amount of solid ink from the viewpoint of ensuring sufficient adhesiveness of the ink to the printed material, and has an appropriate ink viscosity. From the viewpoint of work efficiency during ink production and printing, it is preferably 25% by mass or less, and more preferably 6 to 15% by mass.

(Vinyl chloride vinyl acetate copolymer resin)
Further, in the liquid printing ink of the present invention, a vinyl chloride vinyl acetate copolymer resin may be used in combination with the polyurethane resin, which is preferable.

As the vinyl chloride vinyl acetate copolymer resin is not particularly limited, known ones can be used, but among them, a vinyl chloride vinyl chloride copolymer copolymer resin having a hydroxyl group is preferable, and the hydroxyl value is 50 to 200 mgKOH / g and the above. A vinyl chloride vinyl chloride copolymer copolymer resin having a hydroxyl group in which the content ratio of the vinyl chloride component in the copolymer resin is 80 to 95% by weight is still preferable.

The vinyl chloride vinyl acetate copolymer resin having a hydroxyl group used in the present invention can be obtained by two kinds of methods. One is obtained by copolymerizing a vinyl chloride monomer, a vinyl acetate monomer and a vinyl alcohol in an appropriate ratio. The other is obtained by copolymerizing vinyl chloride and vinyl acetate and then partially saponifying the vinyl acetate. In the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group, the properties of the resin film and the resin dissolution behavior are determined by the monomer ratio of vinyl chloride, vinyl acetate and vinyl alcohol. That is, vinyl chloride imparts toughness and hardness of the resin film, vinyl acetate imparts adhesiveness and flexibility, and vinyl alcohol imparts good solubility in polar solvents.

The monomer ratio of the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group is, for example, blocking resistance when vinyl chloride is 80 to 95 parts by mass with respect to 100 parts by mass of the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group. It is preferable that the adhesiveness is well-balanced. If it is 80 parts by mass or more, the toughness of the resin film can be maintained and blocking resistance can be ensured. If it is 95 parts by mass or less, the resin film does not become too hard and the adhesiveness is unlikely to decrease. The hydroxyl value obtained from vinyl alcohol is preferably 50 to 200 mgKOH / g. If it is 50 mgKOH / g or more, the solubility in a polar solvent is good, and the printability is easily stable. If it is 200 mgKOH / g or less, good laminating suitability can be maintained.

When the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group is used in combination, it is preferably in the range of 1 to 30% with respect to the total resin solid content of the liquid printing ink.

(Chlorinated polypropylene resin)
Further, in the liquid printing ink of the present invention, a chlorinated polypropylene resin may be used in combination with the polyurethane resin. Known chlorinated polypropylene resins can be used without particular limitation, but among them, when the degree of chlorination is 30 to 45% and the weight average molecular weight is 5000 to 50,000, the solubility in an organic solvent and the adhesion to the base film are obtained. It is preferable that the sex is well-balanced. Here, the degree of chlorination in the present invention is the weight% of chlorine atoms in the chlorinated polypropylene resin.

When the chlorinated polypropylene resin is used in combination, it is preferably 0.1 to 3.0% by mass with respect to the total solid content of the liquid printing ink. In this range, an ink having a better balance of solubility in an organic solvent and adhesion to a base film can be obtained.
The chlorinated polypropylene resin may be used in combination with the polyurethane resin, or may be used in combination with the polyurethane resin and a vinyl chloride vinyl acetate copolymer resin having a hydroxyl group.

(Other resins)
Further, examples of the resin used in combination with the liquid printing ink of the present invention as needed include ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyamide resin, acrylic resin, polyester resin, alkyd resin, and polyvinyl chloride. Examples thereof include resins, rosin-based resins, rosin-modified maleic acid resins, ketone resins, cyclized rubbers, rubber chlorides, butyral, and petroleum resins. The combined resin can be used alone or in combination of two or more. The content of the combined resin is preferably 1 to 25% by mass, more preferably 2 to 15% by mass, based on the total mass of the ink.

(solvent)
The liquid printing ink of the present invention includes, for example, aromatic organic solvents, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and ester solvents such as ethyl acetate, n-propyl acetate, butyl acetate and propylene glycol monomethyl ether acetate. Examples thereof include alcohol solvents such as n-propanol, inopropanol, n-butanol, and propylene glycol monomethyl ether, which can be used alone or in admixture of two or more. In recent years, from the viewpoint of working environment, it is desirable not to use aromatic solvents such as toluene and xylene and solvents of ketones.

(water)
Water may be added to the liquid printing ink of the present invention together with the organic solvent as a volatile component. By adding water, the drying property of the ink can be controlled, and especially in gravure printing, the gradation portion having a small amount of ink transfer, which is a feature thereof, can be beautifully reproduced. The amount of water added is preferably in the range of 0.3 to 10% by mass of the total amount of the ink composition from the viewpoint of improving printability. When the amount of water added is 0.3% by mass or more, the reproducibility of the gradation portion tends to be good without deteriorating the effect of suppressing the drying of the ink, and the amount of water added is 10% by mass of the total amount of ink. If it is the following, it is possible to suppress the decrease in ink stability.
Further, by adding such water, it is possible to reduce the organic solvent component used, which leads to environmental friendliness. Water may be added to the organic solvent in advance to form a water-containing organic solvent, or a specific amount may be added separately.

(Other additives)
In the present invention, if necessary, a combined resin, extender pigment, pigment dispersant, leveling agent, defoamer, wax, plasticizer, infrared absorber, ultraviolet absorber, fragrance, flame retardant and the like can also be included. ..

(Dispersant)
In order to stably disperse the titanium oxide (A) and the inorganic filler (B) in an organic solvent, the resin alone can be dispersed, but a dispersant can also be used in combination to more stably disperse the pigment. As the dispersant, surfactants such as anionic, nonionic, cationic and zwitterionic can be used. For example, a comb-shaped polymer compound obtained by adding polyester to polyethyleneimine, an alkylamine derivative of an α-olefin maleic acid polymer, or the like can be mentioned. Specific examples thereof include the Sol Spurs series (ZENECA), the Azisper series (Ajinomoto), and the Homogenol series (Kao). Moreover, BYK series (Big Chemie), EFKA series (EFKA) and the like can also be used as appropriate. The dispersant is preferably contained in the ink in an amount of 0.05% by mass or more and 5% by mass or less from the viewpoint of laminating suitability with respect to the total mass of the ink from the viewpoint of storage stability of the ink, and more preferably 0. It is in the range of 1 to 2% by mass.

The liquid printing ink of the present invention can be produced by dissolving and / or dispersing the titanium oxide (A), the inorganic filler (B), the binder resin and the like in an organic solvent.

The particle size distribution of the pigment in the pigment dispersion is adjusted by appropriately adjusting the size of the pulverized media of the disperser, the filling rate of the pulverized media, the dispersion treatment time, the discharge rate of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As the disperser, generally used, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill and the like can be used.
If the ink contains air bubbles or unexpectedly coarse particles, it is preferable to remove them by filtration or the like in order to deteriorate the quality of the printed matter. As the filter, a conventionally known one can be used.

The viscosity of the ink produced by the above method is in the range of 10 mPa · s or more from the viewpoint of preventing the pigment from settling and appropriately dispersing the pigment, and 1000 mPa · s or less from the viewpoint of workability efficiency during ink production or printing. preferable. The viscosity is the viscosity measured at 25 ° C. with a B-type viscometer manufactured by Tokimec.
The viscosity of the ink can be adjusted by appropriately selecting the type and amount of raw materials used, such as polyurethane resin, colorant, and organic solvent. Further, the viscosity of the ink can be adjusted by adjusting the particle size and the particle size distribution of the pigment in the ink.

(Printed matter)
The printed matter of the present invention is a printed matter having a printed layer formed by printing the liquid printing ink of the present invention on a substrate. The liquid printing ink of the present invention has excellent adhesion to various base materials and can be used for printing on paper, synthetic paper, thermoplastic resin film, plastic products, steel plates, etc. It is useful as an ink for gravure printing using a gravure printing plate, or for flexographic printing using a flexographic printing plate such as a resin plate, but for an inkjet method in which ink is ejected from an inkjet nozzle without using a plate. It excludes ink.
That is, in the case of an inkjet ink, the ink droplets ejected from the nozzle directly adhere to the substrate to form a printed matter, whereas in the liquid printing ink of the present invention, the printing ink is once adhered and transferred to the printing plate or the printing pattern. After that, only the ink is brought into close contact with the base material again, and if necessary, it is dried to obtain a printed matter.
The film thickness of the printing ink formed by the gravure printing method or the flexographic printing method using the liquid printing ink of the present invention is, for example, 10 μm or less, preferably 5 μm or less.

Examples of the base material include polyamide resins such as nylon 6, nylon 66, and nylon 46, polyethylene terephthalate (hereinafter sometimes referred to as PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, and polybutylene terephthalate. Polyester resin such as polybutylene naphthalate, polyhydroxycarboxylic acid such as polylactic acid, biodegradable resin such as aliphatic polyester resin such as poly (ethylene succinate) and poly (butylene succinate), polypropylene, polyethylene, etc. Examples thereof include a film made of a thermoplastic resin such as a polyolefin resin, a polyimide resin, a polyarylate resin, or a mixture thereof, and a laminate thereof. Among them, a film made of polyester, polyamide, polyethylene, and polypropylene can be preferably used. These base films may be unstretched films or stretched films, and the production method thereof is not limited. Further, the thickness of the base film is not particularly limited, but usually it may be in the range of 1 to 500 μm.
The printed surface of the base film is preferably corona discharge treated, and silica, alumina, or the like may be vapor-deposited.

(Laminate)
Further, the liquid printing ink of the present invention can produce not only a single printing layer but also a laminate having at least a first printing layer and a second printing layer on a plastic film in this order.
The liquid printing ink of the present invention, wherein the first printing layer and the second printing layer contain a binder resin, an organic solvent, a colorant, titanium oxide (A) obtained by a sulfuric acid method, and an inorganic filler (B). It is characterized in that it is a printed layer formed from.
Further, when the second printing layer is an overprint varnish, it may not contain a colorant, or various pigments may be used for the purpose of coloring, and a white pigment is preferable.

By using a polyurethane urea resin as the binder resin for the first printing layer, the coating film is flexible, has high adhesion to the plastic film, and has high followability with deformation of the film base material. Further, the polyurethane urea resin is excellent in pigment dispersibility, resolubility at the time of printing, and color development when the pigment is dispersed, and has good compatibility with the pigment.

Further, the liquid printing ink of the present invention can form a laminate having a first printing layer and a third printing layer adjacent to the second printing layer in this order, for example, a polyurethane urea resin. A first printing layer formed of a printing ink containing a colorant, a second white printing layer formed of a liquid printing ink containing a white pigment as a colorant, and a third white printing layer. A laminate having this order can also be produced.
The first printing layer formed on the plastic film with the printing ink containing the polyurethane urea resin and the colorant can form a pattern with the colorant, and the second printed layer formed with the liquid printing ink containing the white pigment. The white print layer and the third print layer can be used as the background of the pattern.
When the third printing layer is an overprint varnish, it may not contain a colorant, or various coloring pigments may be used for coloring purposes, and a white pigment is preferable.

The present invention will be described in more detail with reference to Examples. Hereinafter, "parts" and "%" are both based on mass. Blanks in the table indicate that they have not been mixed.

The weight average molecular weight (in terms of polystyrene) measured by GPC (gel permeation chromatography) in the present invention was measured using an HLC8220 system manufactured by Toso Co., Ltd. under the following conditions.
Separation column: Uses 4 TSKgelGMHR-N manufactured by Tosoh Corporation. Column temperature: 40 ° C. Moving layer: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow velocity: 1.0 ml / min. Sample concentration: 0.4% by mass. Sample injection volume: 100 microliters. Detector: Differential refractometer.
The viscosity was measured at 25 ° C. with a Tokimec B-type viscometer.
The hydroxyl value is the amount of hydroxyl groups in 1 g of resin calculated by back titrating the remaining acid with alkali when the hydroxyl groups in the polyurethane resin are acetylated with an excess acetyl reagent, and potassium hydroxide (KOH) is used. It is shown by the number of mg of, and is based on JIS K0070.

(Synthesis Example 1) Polyurethane urea resin solution P-1
84.5 parts of neopentyl glycol adipatediol (hydroxyl value: 56.6 mgKOH / g) and 15.5 parts of polyethylene glycol (hydroxyl hydroxyl group) in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. Valuation: 278 mgKOH / g) and 27.55 parts of isophorone diisocyanate were charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 2.84% by weight, and then ethyl acetate was added thereto. 68.7 parts were added to make a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.83 parts of isophorone diamine, 0.11 part of di-n-butylamine, 136.8 parts of ethyl acetate and 110.7 parts of isopropyl alcohol, and 5 at 45 ° C. The mixture was stirred for a time to obtain a polyurethane urea resin solution P-1.
The obtained polyurethane urea resin solution P-1 has a resin solid content concentration of 30.4% by weight, a resin solid content Mw of 54,000, and a urethane bond concentration of 1.20 mmol / by a calculation method according to the formula (1). It was g.

Urethane bond concentration = {(W1 x OH1 + W2 x OH2 + ... + Wi x OHi) x 1000} / (56100 x S) Expression (1)

In formula (1), they are as follows.
When a plurality of types of polyols are used, they are calculated as polyol 1, polyol 2 to polyol i, respectively.
W1: Mass of polyol 1 OH1: Hydroxyl value of polyol 1 W2: Mass of polyol 2 OH2: Mass of polyol 2 Wi: Mass of polyol i OHi: Hydroxyl value of polyol i S: Mass of urethane resin solid content

Polyurethane urea resin (137.76 parts in total) contains 11.4% by mass of polyethylene glycol (15.5 parts) as a polyether polyol.

(Synthesis Example 2) Polyurethane urea resin solution P-2
75 parts of neopentyl glycol adipatediol (hydroxyl value: 224 mgKOH / g) and 25 parts of polyethylene glycol (hydroxyl value: 278 mgKOH / g) in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. And 58.74 parts of isophorone diisocyanate were charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 2.80% by mass, and then 85.5 parts of ethyl acetate was added thereto. A uniform solution of urethane prepolymer was prepared. Next, the urethane prepolymer solution was added to a mixture consisting of 9.66 parts of isophorone diamine, 0.11 parts of di-n-butylamine, 170.1 parts of ethyl acetate and 137.6 parts of isopropyl alcohol, and 5 at 45 ° C. The mixture was stirred for a time to obtain a polyurethane urea resin solution P-2.
The obtained polyurethane urea resin solution P-2 has a resin solid content concentration of 30.4% by mass and a resin solid content Mw of 54,000, and the urethane bond concentration is calculated by the same calculation method as in Synthesis Example 1. It was 50 mmol / g.
Polyurethane urea resin (total 168.51 parts) contains 14.8% by mass of polyethylene glycol (25 parts) as a polyether polyol.

(Preparation of vinyl chloride vinyl acetate copolymer resin solution)
A vinyl chloride vinyl acetate copolymer resin having a hydroxyl group used in combination with a polyurethane urea resin (vinyl chloride / vinyl acetate / vinyl alcohol = 92/3/5, hydroxyl value (mgKOH) = 64 with a resin monomer composition of% by weight). A 15% solution was prepared with ethyl acetate, which was made into a vinyl chloride resin solution (B-1).

(Chlorinated polypropylene resin)
As the chlorinated polypropylene, "Supercron 390S chlorine content 36%" manufactured by Nippon Paper Chemicals Co., Ltd. was used.

(Example, Comparative Example Liquid printing ink manufacturing method)
Using the synthesized polyurethane resin solution, the mixture mixed at the blending ratios shown in Table 1 was kneaded using a mighty mill (manufactured by Inoue Seisakusho Co., Ltd.), and described in Examples 1 to 13 and Comparative Examples 1 to 6. White inks were prepared, and the following evaluations were carried out for each of them.

[Manufacturing method of printed matter]
The viscosity of the obtained liquid printing ink was adjusted to 15 seconds (25 ° C.) with Zahn Cup # 3 (manufactured by Rigosha) with a mixed organic solvent of ethyl acetate / isopropyl alcohol = 80/20. The adjusted ink is a biaxially stretched polyester film (hereinafter referred to as PET film, E-5100, thickness 12 μm, manufactured by Toyobo Co., Ltd.) in which one side is corona-treated by a gravure calibrator equipped with a gravure plate having a plate depth of 30 μm. It was printed on and dried to obtain a PET film printed matter.

[Hiding]
The transmission density of the PET film printed matter obtained by the above-mentioned "method for producing printed matter" was measured with a transmission densitometer X-Rite 361T (V). If the concealment property is 0.22 or more, it is considered to be acceptable.

[Plate coverability]
Adjust the viscosity of the liquid printing ink to 16 seconds (25 ° C) with Zahn Cup # 3 (manufactured by Rigo Co., Ltd.) with a mixed organic solvent of ethyl acetate / isopropyl alcohol = 50/50, and attach a laser gravure plate with a plate depth of 30 μm. Using an MD type gravure printing machine (manufactured by Fuji Machinery Co., Ltd.), printing was performed on the treated side of a PET film having a corona discharge treatment on one side. The degree of stain (plate fog degree) of the highlight non-printed portion when the printing speed of the gravure plate was 600 mmφ and the printing speed was 200 m / min was visually evaluated. If the plate covering property is 6 or more, it is considered to be passed.
(Evaluation criteria)
10: No stains on the non-printed part 9: Slight stains on the non-printed part 8: Intermediate between 7 and 9 7: Slight stains on the non-printed part 6: Intermediate between 5 and 7 5: There is dirt on the non-printed part 4: About halfway between 3 and 5 3: There is a lot of dirt on the non-printed part 2: About halfway between 1 and 3

[Adhesiveness]
After leaving the PET film printed matter obtained by the above-mentioned "method for manufacturing printed matter" for one day, a cellophane tape (Nichiban 12 mm width) is attached to the printed surface, and the appearance of the printed film when it is rapidly peeled off is observed. Visual evaluation was performed.
(Evaluation criteria)
10: The print film did not peel off at all.
9: 90% or more of the printing film remained on the film 8: 80% or more to less than 90% of the printing film remained on the film 7: 70% or more to less than 80% of the printing film remained on the film 6: Printing 60% to less than 70% of the film remained on the film 5: 50% to less than 60% of the print film remained on the film 4: 40% to less than 50% of the print film remained on the film 3: 30% to less than 40% of the print film remained on the film 2: 20% to less than 30% of the print film remained on the film 1: 10% to less than 20% of the print film remained on the film 0 : Less than 10% of the print film remained on the film

[Blocking resistance]
The PET film printed matter obtained by the above-mentioned "method for producing printed matter" is laminated so that the printed surface and the non-printed surface are in contact with each other, a load of 10 kgf / cm ² is applied, and aged for 12 hours in an environment of 40 ° C. After taking out the ink, the state of ink transfer to the non-printed surface was visually evaluated.
(Evaluation criteria)
5: Ink transfer to non-printing surface: 0% to less than 20% 4: Ink transfer to non-printing surface: 20% or more to less than 40% 3: Ink transfer to non-printing surface: 40% or more Less than 60% 2: Ink transfer to non-printing surface: 60% or more to less than 80% 1: Ink transfer to non-printing surface: 80% or more

[Lamination suitability]
A dry laminating machine (manufactured by DIC Engineering) is applied to the printed surface of the PET film printed matter obtained by the above "method for manufacturing printed matter" with a urethane-based dry laminating adhesive Dick Dry LX-703VL / KR-90 (manufactured by DIC). After coating, a non-stretched polypropylene film (hereinafter, R-CPP: ZK-75 50 μm manufactured by Toray Synthetic Film Co., Ltd.) was laminated on the adhesive-coated surface. Then, it was aged at 40 ° C. for 5 days to obtain a laminate.
The obtained laminate was cut into a width of 15 mm, and a peeling test of 90 degrees was performed at a pulling speed of 300 mm / min.
(Evaluation criteria)
5: Laminate strength is 5N / 15mm or more.
4: Laminate strength is 4N / 15mm or more and less than 5N / 15mm.
3: Laminate strength is 3N / 15mm or more and less than 4N / 15mm.
2: Laminate strength is 2N / 15mm or more and less than 3N / 15mm.
1: Laminate strength is less than 1N / 15mm.

The results are shown in Tables 1-3.

In the table, the abbreviations are as follows.
Titanium oxide T: Alumina silica-treated titanium oxide U with a mass ratio of titanium oxide / alumina / silica (Ti / Al / Si) of 92/4/4 and a moth hardness of 7.0 obtained by the sulfuric acid method. : Alumina silica-treated titanium oxide titanium oxide V: sulfuric acid method, which is obtained by the sulfuric acid method and has a mass ratio of titanium oxide / alumina / silica (Ti / Al / Si) of 90/3/7 and a moth hardness of 7.0. Titanium oxide / alumina / silica (Ti / Al / Si) having a mass ratio of 97/3/0 and having a Morse hardness of 7.0 was obtained by the alumina-treated titanium oxide titanium oxide W: chlorine method. , Titanium oxide / alumina / silica (Ti / Al / Si) mass ratio 90/3/7, alumina silica treated titanium oxide kaolin with moth hardness 7.0: particle size 0.2, moth hardness 2.0
Calcium carbonate: particle size is 0.5, Mohs hardness is 3.0
Barium sulphate: particle size 0.7, Mohs hardness 3.5
Organic filler (acrylic resin): Acrylic beads "Techpolymer MBX-5" manufactured by Sekisui Plastics Co., Ltd. have a particle size of 5.0 and a Mohs hardness of 2.0.

As a result, the liquid printing ink of the example was excellent in hiding property, plate fog property, adhesiveness, blocking property, and laminating suitability.
As the titanium oxide, the ink using titanium oxide obtained by the sulfuric acid method (Examples 1 to 13) is inferior to the ink using titanium oxide obtained by the chlorine method (Comparative Example 6). I understand.

Further, both the inks containing no inorganic filler (Comparative Examples 1, 2, 3 and 4) and the inks containing an organic filler instead of the inorganic filler (Comparative Example 5) are inferior in either hiding property or plate fog property. The result was.
When the amount of titanium oxide is 30% by mass with respect to the total amount of the ink, the ink without the inorganic filler (Comparative Example 1) shows a high plate fog property of 8 but is inferior in hiding property. On the other hand, it can be seen that the inks (Examples 1, 9, and 13) in which the inorganic filler is used in combination have improved concealment while maintaining plate fog.
Further, in the case of an ink in which the amount of titanium oxide is 40% by mass with respect to the total amount of the ink, the ink without the inorganic filler (Comparative Example 3) shows a high hiding property of 0.23, but is inferior in plate fog. On the other hand, it can be seen that the inks (Examples 3 and 11) in which the inorganic filler is used in combination have improved plate fogability while maintaining concealment.

Claims (8)

A liquid printing ink containing a binder resin, an organic solvent, and a colorant, which contains titanium oxide (A) and an inorganic filler (B) obtained by a sulfuric acid method. The liquid printing ink according to claim 1, which has a treated layer made of at least alumina and / or silica on the surface of the titanium oxide (A). The liquid printing ink according to claim 1 or 2, wherein the inorganic filler (B) has a Mohs hardness of 1 to 5. The liquid printing ink according to any one of claims 1 to 3, wherein the inorganic filler (B) is a clay mineral. The liquid printing ink according to any one of claims 1 to 4, wherein the mass ratio of the titanium oxide (A) to the inorganic filler (B) is 99: 1 to 1:99. The invention according to any one of claims 1 to 5, wherein the binder resin is a polyurethane urea resin having a weight average molecular weight of 15,000 to 100,000 and a urethane bond concentration of 1.2 mmol / g or more and 2.5 mmol / g or less. Liquid printing ink. A printed matter having a printing layer formed by printing the liquid printing ink according to any one of claims 1 to 6 on a substrate. A laminate in which an adhesive layer and a film layer are laminated in this order on the print layer of the printed matter according to claim 7.