JP4120763B2 - Composite pigment, ink composition and printed matter - Google Patents

Description

【００６４】
表１の結果、顔料として二酸化チタンのみ用いた比較例１では、隠蔽率は優れていたが、白色度が低かった。また、二酸化チタン及び炭酸カルシウムを複合粒子としていない比較例２及び３では、隠蔽率及び白色度が悪かった。また、表面処理を行わなかった比較例４では、隠蔽率及び白色度がやや悪かった。
【００６５】
一方、本発明実施例では、隠蔽率及び白色度が優れていた。また、本発明実施例では、ツブ度が小さく、粘度は比較例と同等であった。[0001]
[Field of the Invention]
The present invention relates to a composite pigment having high hiding power, an ink composition containing the pigment, and a printed matter printed with the ink composition.
[0002]
[Prior art]
Printed materials are roughly classified into those printed on an absorbent substrate such as paper and those printed on a non-absorbent substrate such as plastic film, aluminum foil and cellophane.
[0003]
In recent years, printed materials printed on non-absorbent substrates have increased. For example, the packaging of mail has been simplified and printed plastic film packaging has become increasingly used. Also, printed materials based on metals such as aluminum foil packaging materials and metal cans are often used.
[0004]
The non-absorbent substrate is usually coated on the surface with an ink containing a pigment such as titanium dioxide having high concealability, and characters and designs are printed with the colored ink.
[0005]
When printing on any substrate, the printing ink is required to be concealed, and in the case of white ink, the whiteness is also required, but the ink used for these non-absorbing substrates is particularly high. Concealability or even whiteness is required. This is because, in the case of a non-absorbing substrate, a printed layer is formed on the surface of the substrate because it does not absorb even when the same ink amount is used. If the printed layer is thick, it is easily peeled off by contact with other articles. For this reason, the printing layer must be thinned, and accordingly, a high concealing property is required. In addition, when printing on a metal substrate, it is necessary to hide a dark metal color unlike paper.
[0006]
For hiding the base and imparting whiteness, pigments such as titanium dioxide and zinc oxide having a high refractive index are usually used.
[0007]
However, conventionally used pigments are not sufficient in terms of concealability or even whiteness as ink pigments used for non-absorbing substrates. Although it is conceivable to increase the pigment concentration in the ink for the purpose of improving the concealing property, in this case, there are problems such as wear of the printing plate and reduction in adhesion between the ink and the plate.
[0008]
[Problems to be solved by the invention]
The main object of the present invention is to provide a pigment from which an ink composition excellent in concealability of a printing substrate can be obtained, an ink composition using the pigment, and a printed material printed with the ink composition.
[0009]
[Means for Solving the Problems]
The present inventors have repeated researches to achieve the above-mentioned object, and have found the following findings.
(1) The ink composition containing titanium dioxide / calcium carbonate composite particles in which calcium carbonate particles are fixed on the surface of titanium dioxide particles has a very high concealing property and a very high whiteness in the case of white ink. Even when applied on a non-absorbent substrate, the color of the substrate can be reliably concealed. This is considered to be due to the fact that the calcium carbonate particles act as spacers and increase the distance between the titanium dioxide particles.
(2) Titanium dioxide particles and zinc oxide particles, which have been used as pigments in conventional printing inks, were small particles of about 50 to 500 nm, and thus had a problem that it took time to disperse in the ink resin. The titanium dioxide / calcium carbonate composite particles in which the calcium carbonate particles are fixed on the surface of the titanium dioxide particles have a large particle size and thus have good dispersibility in printing ink.
(3) Surface treatment of the titanium dioxide / calcium carbonate composite particle surface in which calcium carbonate particles are fixed on the surface of titanium dioxide particles with at least one compound selected from the group consisting of resin acids, fatty acids and salts and derivatives thereof. In this case, the wettability between the surface of the composite pigment and the ink composition is improved, and as a result, the dispersibility of the pigment in the ink composition is improved.
[0010]
As a result of further research based on the above findings, the present invention provides composite pigments, ink compositions and printed matter of the following items.
[0011]
Item 1. Titanium dioxide / calcium carbonate composite particles in which calcium carbonate particles are fixed on the surface of titanium dioxide particles, having a specific surface area of 5 to 30 m²A surface treatment layer containing at least one compound selected from the group consisting of resin acids, fatty acids and salts and derivatives thereof is formed on the surface of the composite particles that are / gThe titanium dioxide particles have a particle size of 50 to 500 nm, the calcium carbonate particles have a particle size of 30 to 400 nm,The weight ratio of titanium dioxide to calcium carbonate in the titanium dioxide / calcium carbonate composite particles is 1:99 to 50:50.The weight ratio of the composite particles to the surface treatment layer is 100: 0.2 to 100: 20.Composite pigment.
[0012]
Item 2. In addition to at least one compound selected from the group consisting of resin acids, fatty acids, and salts and derivatives thereof, the surface treatment layer includes an anionic surfactant different from the resin acids, fatty acids, and salts and derivatives thereof. Item 2. A composite pigment according to Item 1.
[0013]
Item 3.Calcium carbonate is precipitated calcium carbonateItem 3. The composite pigment according to Item 1 or 2, wherein
[0014]
Item 4. Calcium carbonateThe ratio of the length of the major axis to the minor axis of the particles is 0.8-1The term 1From3One ofThe composite pigment described in 1.
[0015]
Item 5.Item 15. The composite pigment according to any one of 4And an ink composition containing a binder resin.
[0016]
Item 6. Item 1~ 4The composite pigment according to any one ofAn ink composition containing titanium dioxide particles and a binder resin.
[0017]
Item 7. Term5 or6'sINki compositionPrinted matter having a printed layer printed using
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The composite pigment of the present invention
The composite pigment of the present invention has at least one selected from the group consisting of resin acids, fatty acids, salts thereof and derivatives on the surface of titanium dioxide / calcium carbonate composite particles in which calcium carbonate particles are fixed on the surface of titanium dioxide particles. A surface treatment layer containing the above compound is formed. In the present invention, the state in which the calcium carbonate particles are “fixed” on the surface of the titanium dioxide particles includes a state in which the titanium dioxide particles and the calcium carbonate particles are adsorbed to each other by van der Waals force.
[0021]
The weight ratio of titanium dioxide to calcium carbonate in the titanium dioxide / calcium carbonate composite particles is usually about 1:99 to 50:50, and the specific surface area of the titanium dioxide / calcium carbonate composite particles is usually 5 to 30 m.²/ G or so.
Composite particles
<Form>
The crystal form of the titanium dioxide particles is not particularly limited. For example, an anatase type or rutile type can be used. The particle size of the titanium dioxide particles is usually about 50 to 500 nm, preferably about 100 to 300 nm. If it is in the range prescribed | regulated to this invention, the ink composition which has high concealability will be obtained.
[0022]
As the calcium carbonate, both natural calcium and synthetic calcium (precipitated calcium carbonate) can be used, but it is preferable to use precipitated calcium carbonate. Since natural calcium carbonate is produced by mechanically grinding and classifying limestone, the particle size distribution is relatively wide and the particle shape tends to be non-uniform. In contrast, precipitated calcium carbonate has a narrow particle size distribution and a relatively uniform particle shape. As a result, with precipitated calcium carbonate, it is difficult for the particles to be closely packed, and a space is formed between the particles, so that the concealability of the composite particles is improved, and as a result, an ink composition with high concealability is obtained.
[0023]
The particle size of the calcium carbonate particles is preferably about 30 to 400 nm, particularly about 50 to 150 nm. When the particle size of the calcium carbonate particles is too small, the distance between the titanium dioxide particles becomes small, and the concealability of the ink composition is lowered. On the other hand, if the particle size is too large, it is difficult to adhere to the surface of the titanium dioxide particles, and the ratio of the particles existing away from the titanium dioxide becomes high and the concealability of the ink composition is lowered. Such a problem is unlikely to occur within the range defined in the present invention.
[0024]
In the present invention, the particle size is a value measured by X-ray diffractometry or scanning electron microscope observation, and the particle size range refers to a case where at least 80% or more of the particles fall within the range.
[0025]
The particle shape of calcium carbonate is not particularly limited, and may be any shape such as a sphere or an n-hedron (n is a natural number). In any case, it is preferable that the ratio of the length of the major axis to the minor axis is usually about 0.8 to 1, particularly about 0.9 to 1, and more particularly about 1. In particular, a spherical shape or a cubic shape is preferable. The particle shape is preferably as uniform as possible.
[0026]
In the case of precipitated calcium carbonate, such calcium carbonate particles can be produced by blowing carbon dioxide into a calcium hydroxide suspension.
[0027]
The ratio of titanium dioxide to calcium carbonate in the titanium dioxide / calcium carbonate composite particles is usually about 1:99 to 50:50 by weight. In particular, it is preferably about 5:95 to 40:60, more preferably about 15:85 to 30:70. If the amount of calcium carbonate is too small compared to titanium dioxide, the titanium dioxide particles are aggregated and the concealing property is lowered, and if too much, the concealing property is also lowered. Such a problem is unlikely to occur within the range defined in the present invention.
[0028]
    Titanium dioxide / calcium carbonate composite particles generally have a specific surface area of generally 5-30m²/ G or so. Especially 8-15m²/ G is preferable. In the present invention, the specific surface area is a value measured by a nitrogen gas adsorption method using a specific surface area measuring device (trade name: Flowsorb II2300, manufactured by Shimadzu Corporation) in the BET method.
<Production Method> The titanium dioxide / calcium carbonate composite particles are not limited thereto, but for example, titanium dioxide particles and calcium carbonateSiuIt is possible to produce the particles by mixing them in an aqueous phase.
[0029]
Here, the repulsive force between particles in the liquid is related to the zeta potential. The zeta potential is a potential difference between the outermost surface (sliding surface) of the liquid layer that moves in close contact with the solid and the inside of the liquid when the solid is present in the liquid and the solid and the liquid move relative to each other. Here, the pH of the aqueous phase that is the dispersion medium is adjusted so that the sum of the zeta potential of the titanium dioxide particles and the zeta potential of the calcium carbonate particles is minimized or the zeta potentials of both are opposite signs. For example, in the case of a combination of titanium dioxide particles and precipitated calcium carbonate particles, both particles may be dispersed and mixed in an aqueous phase having a pH of about 6-11.
[0030]
The weight ratio of titanium dioxide particles and calcium carbonate particles dispersed in the aqueous phase may be about 1:99 to 50:50.
Surface treatment layer
The titanium dioxide / calcium carbonate composite particles are covered with a surface treatment layer containing at least one compound selected from the group consisting of resin acids, fatty acids, and salts and derivatives thereof. The entire surface of the composite particle may be covered with the surface treatment layer or may be a part of the surface that is not partially covered, but the entire surface is preferably covered with the surface treatment layer.
[0031]
The ratio of the surface treatment layer to the composite particles is usually about 0.2 to 20 parts by weight, particularly about 0.5 to 10 parts by weight, more preferably about 0.8 to 5 parts by weight, based on 100 parts by weight of the composite particles. If the surface treatment layer is too thin, the dispersibility of the composite pigment is poor, and a highly concealing ink composition cannot be obtained. On the other hand, when the surface treatment layer is too thick, the concealability of the ink composition is lowered. Within the range specified in the present invention, an ink composition having good dispersibility of the composite pigment and having a practically sufficient hiding property or a practically sufficient whiteness can be obtained.
Examples of the resin acid include, but are not limited to, abietic acid, neoabietic acid, parastrinic acid, levopimaric acid, dehydroabietic acid, pimaric acid, isopimaric acid, sandaracopimaric acid, comnic acid, anticopal acid, lambertian acid, dihydroacid Examples include agato acid. Among these, abietic acid, neoabietic acid, dehydroabietic acid, or parastronic acid is preferable. Abietic acid is particularly preferable.
Examples of the resin acid salt include alkali metal salts such as sodium salt and potassium salt of the resin acid exemplified above, and alkaline earth metal salts such as magnesium salt and calcium salt. As the resin acid salt, potassium abietate, potassium neoabietic acid, potassium dehydroabietic acid or potassium parastrinate is preferred. In particular, potassium abietate is preferable.
[0032]
Examples of the resin acid derivative include, but are not limited to, disproportionated rosin, maleated rosin, polymerized rosin, and rosin ester. In particular, disproportionated rosin or rosin ester is preferred.
[0033]
Examples of fatty acids include, but are not limited to, saturated fatty acids or unsaturated fatty acids having about 6 to 31 carbon atoms. Specifically, as the saturated fatty acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, melicic acid, etc. It can be illustrated. Among these, palmitic acid, stearic acid, lauric acid or oleic acid is preferable.
[0034]
Examples of the saturated fatty acid salt include alkali metal salts such as sodium salts and potassium salts of the saturated fatty acids exemplified above, and alkaline earth metal salts such as magnesium salts and calcium salts. As the saturated fatty acid salt, sodium palmitate, sodium stearate or sodium laurate is preferred.
[0035]
Examples of unsaturated fatty acids include unsaturated fatty acids having one double bond such as oleic acid, palmitoleic acid, erucic acid, caproleic acid, lindelic acid, eicosenoic acid, and two unsaturated bonds such as linoleic acid. Examples include unsaturated fatty acids having 3 double bonds such as fatty acid, hiragonic acid and linolenic acid, unsaturated fatty acids having 4 double bonds such as arachidonic acid, and unsaturated fatty acids having triple bonds such as talylic acid. . Of these, oleic acid or erucic acid is preferred.
[0036]
Examples of the unsaturated fatty acid salt include alkali metal salts such as sodium salts and potassium salts of the unsaturated fatty acids exemplified above, and alkaline earth metal salts such as magnesium salts and calcium salts. As the salt of unsaturated fatty acid, sodium oleate or sodium erucate is preferable.
These resin acids, fatty acids, and salts and derivatives of the composition can be used alone or in combination of two or more. Among them, preferred are resin acid compounds such as abietic acid, neoabietic acid, disproportionated rosin or rosin ester, fatty acid compounds such as palmitic acid, stearic acid, lauric acid or oleic acid, or any combination thereof. . In particular, abietic acid, disproportionated rosin, stearic acid or oleic acid, or any combination thereof is preferred.
[0037]
The surface treatment layer preferably contains at least one anionic surfactant. This anionic surfactant is an anionic surfactant that is different from resin acids, fatty acids and their salts and derivatives. Examples of such anionic surfactant include, but are not limited to, alkylbenzene sulfonic acid, alkylbenzene sulfonate, alkyl naphthalene sulfonic acid, alkyl naphthalene sulfonate, alpha olefin sulfonate, alkyl sulfate ester salt, alkyl sulfate Examples include ether sulfate ester salts, alkylphenyl sulfate ester salts, methyl taurate, sulfosuccinate, and ether sulfonate. Among these, alkylbenzenesulfonic acid, alkylbenzenesulfonic acid salt, alkylnaphthalenesulfonic acid or alkylnaphthalenesulfonic acid salt is preferable.
[0038]
The amount of the anionic surfactant used is usually about 0.1 to 2 parts by weight, particularly about 0.3 to 1 part by weight, based on the titanium dioxide / calcium carbonate composite particles. When the amount of the anionic surfactant used is too large, the surface treatment layer is easily peeled off, and when it is too small, the surface treatment with a resin acid or the like becomes insufficient. Such a problem does not occur within the range specified in the present invention.
<Surface treatment method>
The surface treatment layer is not limited thereto, but can be formed as follows, for example.
[0039]
The surface-treated titanium dioxide / calcium carbonate composite particles may be dry particles or a slurry state dispersed in water or an organic solvent such as toluene, xylene, hexane or the like.
[0040]
When the composite particles to be surface-treated are in a slurry state, a surface treatment agent is added to the slurry and stirred to form an adsorption layer (coating layer) of the surface treatment agent on the surface of the composite particles. Thereafter, the slurry is dehydrated using a machine such as a centrifugal dehydrator or a filter press, and the obtained filter cake is dried by exposure to hot air to obtain composite particles (composite pigment) coated with a surface treatment agent. It is done. As the dryer, a hot air box type dryer, a band dryer, a spray dryer or the like can be used. The dried particles are pulverized as necessary for fine adjustment of particle size, pore volume and the like.
[0041]
When the composite particles to be surface-treated are dry particles, the surface treatment agent is added to the dry composite particles, and the mixture is finely adjusted to the desired particle size and pore volume by vigorously stirring and mixing or grinding and mixing while heating. Composite pigments are obtained.
[0042]
The composite particle concentration in the composite particle slurry is set to about 5 to 20% by weight, and the surface treatment layer material is added to about 0.2 to 22% by weight with respect to the composite particles in the slurry, whereby 100 parts by weight of the composite particles are added. Thus, a composite pigment having a surface treatment layer of about 0.2 to 20 parts by weight is obtained.
Ink composition
The ink composition of the present invention is a blend of the composite pigment of the present invention and a binder resin. Moreover, a solvent is normally mix | blended. In addition, a coloring agent, a filler, an additive, etc. may be mix | blended as needed.
[0043]
The compounding ratio of the composite pigment is usually about 5 to 60 parts by weight, particularly preferably about 15 to 40 parts by weight with respect to 100 parts by weight of the ink composition. Further, the blending amount of the binder resin is usually about 5 to 50 parts by weight, particularly about 10 to 40 parts by weight with respect to 100 parts by weight of the ink composition, and the blending amount of the solvent is 100 parts by weight of the ink composition. The amount is usually about 5 to 75 parts by weight, particularly about 10 to 70 parts by weight with respect to parts.
[0044]
When a colorant, a filler and an additive are blended, about 10 to 55 parts by weight (particularly about 20 to 40 parts by weight) of a colorant and 20 parts by weight of a filler with respect to 100 parts by weight of the ink composition. The blending ratio is preferably up to about (particularly about 5 to 15 parts by weight) and up to about 10 parts by weight (particularly up to about 3 parts by weight).
[0045]
Further, in the ink composition of the present invention, it is preferable to blend titanium dioxide particles in addition to the composite pigment. Thereby, concealment property can be improved further. The titanium dioxide particles are not limited thereto, but for example, those of anatase type or rutile type can be used. The particle size is preferably about 50 to 500 nm, particularly about 100 to 300 nm.
[0046]
The compounding ratio of the titanium dioxide particles is preferably such that the composite pigment: titanium dioxide is usually about 99: 1 to 80:20, particularly about 99: 1 to 90:10. When compounding titanium dioxide in addition to the composite pigment, the total amount of the composite pigment and titanium dioxide is usually about 5 to 60 parts by weight, especially about 15 to 40 parts by weight, per 100 parts by weight of the ink composition. Is preferred.
[0047]
The binder resin is not particularly limited, and a known resin can be used as a printing ink resin. Examples of such resins include cured rosin, petroleum resin, maleic resin, acrylic resin, (meth) acrylic resin, polyamide, polyurethane, polyester, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, styrene resin, and chlorinated rubber. And urea resin, melamine resin, ketone resin, polyvinyl butyral, chlorinated polypropylene, polyurethane, nitrocellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, cyclized rubber, and the like. These can be used alone or in admixture of two or more.
[0048]
A colorant is not specifically limited, A conventionally well-known inorganic pigment, an organic pigment, or dye can be used as a colorant of an ink composition. A pigment is preferable in terms of water resistance.
[0049]
Examples of the organic pigment include, but are not limited to, carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthal yellow, chromophthal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, Examples include quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo Bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and daylight fluorescent pigment.
[0050]
Examples of inorganic pigments include, but are not limited to, carbon black, aluminum powder, bronze powder, chrome vermillion, chrome lead, cadmium yellow, cadmium red, ultramarine, bitumen, red, oxide iron, black iron, zinc oxide, etc. Is mentioned.
[0051]
Examples of the dye include, but are not limited to, Tartrazine Lake, Rhodan 6G Lake, Victoria Pure Blue Lake, Alkali Blue G Toner, Brilliant Green Lake, and the like.
[0052]
These colorants can be used alone or in admixture of two or more.
[0053]
A filler is not specifically limited, A well-known thing can be used as a filler of an ink composition. Examples of such fillers include carbonates such as calcium carbonate and magnesium carbonate, sulfates such as precipitated barium sulfate, silicates such as silica and talc, and the like. These can be used alone or in admixture of two or more. In particular, calcium carbonate, precipitated barium sulfate and the like are preferable.
[0054]
As additives, waxes, pigment dispersants, antifoaming agents and the like that are generally used as additives for ink compositions can be used.
[0055]
A solvent is not specifically limited, A well-known thing can be used as a solvent of an ink composition. Examples of such solvents include n-hexane, n-pentane, rubber volatile oil, mineral spirits, aliphatic hydrocarbons such as high boiling petroleum solvents, toluene, xylene, cyclohexane, solvent naphtha, aromatics such as tetralin and dipentene. Aromatic hydrocarbon solvents, ester solvents such as methyl acetate, acetic acid-n-propyl, acetic acid-n-butyl, ethyl acetate, isobutyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, diacetone alcohol, Like ketone solvents like isophorone, methanol, ethanol, isopropanol, n-butanol, sec-butyl alcohol, isobutyl alcohol, cyclohexyl alcohol, 2-methylcyclohexyl alcohol, tridecyl alcohol Alcohol solvents, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycols such as dipropylene glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, glycol ethers such as propylene glycol monobutyl ether, Examples thereof include glycol ether esters such as ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. These can be used alone or in admixture of two or more. In particular, toluene, xylene, methyl ethyl ketone, ethyl acetate and the like are preferable.
Printed matter
The printed matter of the present invention has a printed layer printed with the ink composition of the present invention. The printing layer using the ink composition of the present invention may be a base layer of a surface printing layer such as characters, or may be a surface printing layer on which characters or patterns are drawn. The thickness of the printing layer is not particularly limited, but it may be usually about 10 to 100 μm.
[0056]
The substrate is not particularly limited, and an absorbent substrate such as paper, a non-absorbable substrate such as plastic (polyethylene, nylon, polyethylene terephthalate, etc.), metal (aluminum, stainless steel sheet), cellophane, or the like can be used. .
[0057]
【The invention's effect】
According to the present invention, a pigment capable of obtaining an ink composition having excellent whiteness in the case of white ink and a concealing property of a printing substrate, an ink composition using this pigment, and a printed matter printed with this ink composition Is provided.
[0058]
More specifically, the composite pigment of the present invention has calcium carbonate particles attached to the surface of titanium dioxide particles, and the calcium carbonate particles act as a spacer to increase the distance between the titanium dioxide particles, thereby concealing. It is considered that an ink composition excellent in property or whiteness can be obtained. The ink composition using the composite pigment of the present invention can reliably hide the color of the substrate even when it is thinly applied on a non-absorbing substrate.
[0059]
Further, the composite pigment of the present invention has a particle size as large as about 0.1 to 2 μm (100 to 2000 nm) and has a surface treatment layer, so that the dispersibility in the ink composition is extremely good.
[0060]
【Example】
EXAMPLES Hereinafter, although an Example and a test example are shown and this invention is demonstrated, this invention is not limited to these. In the examples, “parts” means “parts by weight” unless otherwise specified.
Example
Anatase-type titanium dioxide having an average particle diameter of 200 nm and cubic precipitated calcium carbonate having an average particle diameter of 100 nm were mixed at a ratio of 20:80, and water was added to prepare a 20 wt% slurry. The pH was adjusted to 7.8 by blowing carbon dioxide into the mixed slurry. The pH stabilized slurry was passed through a colloid mill. The gap between the colloid mill rotor and stator was set to 100 μm. Also, the residence time in the colloid mill was less than 0.1 seconds. The temperature of the mixture was 20 ° C. The produced 100 nm precipitated calcium carbonate particles adhered to the surface of titanium dioxide by van der Waals force. The resulting composite particles have a titanium dioxide: calcium carbonate weight ratio of 20:80 and a specific surface area of 10 m.²/ G.
[0061]
Next, to this composite particle slurry, 2.0 parts of sodium abietic acid is added to 100 parts of the composite particles, and stirred with a disper for 30 minutes while heating to 50 ° C., and the surface of the composite particles is abietic acid salt. Was processed. Thereafter, the slurry was dehydrated with a filter press or the like, and the obtained filter cake was dried by exposure to hot air and further pulverized to obtain abietic acid salt-treated composite particle powder. As a result, a composite pigment having 1.0 part of the surface treatment layer with respect to 100 parts of the composite particles was obtained.
[0062]
Furthermore, 100g of this composite pigment, 34g of cured rosin (Arakawa Chemical Industries) and 81g of toluene were added, and 400g of stainless steel beads with a diameter of 1.6mm for dispersion were further added, and mixed and dispersed using a paint conditioner. An ink composition was obtained. This ink composition was applied to a polyethylene terephthalate film and dried to obtain a 19 μm thick ink film.
Comparative Example 1
In Examples, instead of the composite pigment, commercially available titanium dioxide (A-220: manufactured by Ishihara Sangyo Co., Ltd.) was used as a pigment, and the others were obtained in the same manner to obtain an ink film.
Comparative Example 2
In Examples, instead of the composite pigment, commercially available titanium dioxide (A-220: manufactured by Ishihara Sangyo Co., Ltd.) and commercially available precipitated calcium carbonate (Unifant-15: manufactured by Shiraishi Kogyo Co., Ltd.) An ink film was obtained in the same manner except that the pigment mixed at a weight ratio of 80 was used.
Comparative Example 3
In Examples, instead of the composite pigment, commercially available titanium dioxide (A-220: manufactured by Ishihara Sangyo Co., Ltd.) and commercially available precipitated calcium carbonate (Unifant-15: manufactured by Shiraishi Kogyo Co., Ltd.) were used at 30:70. Ink films were obtained in the same manner except that the pigments were mixed in the weight ratio.
Comparative Example 4
In Examples, instead of the composite pigment, composite particles not subjected to surface treatment were used, and the others were similarly obtained ink films.
<Test example>
The ink compositions obtained in Examples and Comparative Examples 1 to 4 were evaluated for viscosity and roughness. The viscosity of the ink composition was expressed as the time required for 45 ml of the ink composition to pass through the bore of the Zahn cup using a Zahn cup (3 mm in diameter, 45 ml in volume). The higher the viscosity, the longer the transit time. The dispersibility of the pigment was measured according to JIS K 5101 method. Moreover, the concealment rate of the base material by the ink film obtained by the Example and Comparative Examples 1-4, whiteness, and glossiness were evaluated. The measurement of the concealment rate, whiteness and gloss was based on JIS K 5101 method. The results are shown in Table 1 below.
[0063]
[Table 1]

[0064]
As a result of Table 1, in Comparative Example 1 in which only titanium dioxide was used as the pigment, the hiding ratio was excellent, but the whiteness was low. Moreover, in Comparative Examples 2 and 3 in which titanium dioxide and calcium carbonate were not used as composite particles, the concealment rate and whiteness were poor. Moreover, in the comparative example 4 which did not perform surface treatment, the concealment rate and the whiteness were a little bad.
[0065]
On the other hand, in the Example of this invention, the concealment rate and the whiteness were excellent. Moreover, in the Example of this invention, the degree of protrusion was small and the viscosity was equivalent to the comparative example.

Claims (7)

From titanium dioxide / calcium carbonate composite particles having calcium carbonate particles fixed on the surface of the titanium dioxide particles and having a specific surface area of 5 to 30 m ² / g, resin acids, fatty acids and salts and derivatives thereof A surface treatment layer containing at least one compound selected from the group consisting of titanium dioxide particles having a particle size of 50 to 500 nm, calcium carbonate particles having a particle size of 30 to 400 nm, and titanium dioxide / carbonic acid. the weight ratio of titanium dioxide and calcium carbonate in calcium composite particles 1: 99-50: 50 der is, the weight ratio of the composite particles and the surface treatment layer 100: 0.2 to 100: 20, the composite pigment .  In addition to at least one compound selected from the group consisting of resin acids, fatty acids, and salts and derivatives thereof, the surface treatment layer includes an anionic surfactant different from the resin acids, fatty acids, and salts and derivatives thereof. The composite pigment according to claim 1. The composite pigment according to claim 1 or 2 , wherein the calcium carbonate is precipitated calcium carbonate. The composite pigment according to any one of claims 1 to 3 , wherein the ratio of the major axis to the minor axis of the calcium carbonate particles is 0.8 to 1 . An ink composition comprising the composite pigment according to any one of claims 1 to 4 and a binder resin. An ink composition comprising the composite pigment according to any one of claims 1 to 4 , titanium dioxide particles, and a binder resin. A printed matter having a printed layer printed using the ink composition according to claim 5 .