JP6785174B2 - Oil pigment ink - Google Patents

Description

The present invention relates to oil-based pigment inks.

In the inkjet recording method, highly fluid inkjet ink is ejected as droplets from a fine nozzle, and an image is recorded on a recording medium placed facing the nozzle, enabling high-speed printing with low noise. Therefore, it has spread rapidly in recent years. As inks used in such an inkjet recording method, water-based inks containing water as a main solvent, ultraviolet curable inks (UV inks) containing a high content of polymerizable monomers as main components, and wax as main components are high. A so-called non-aqueous ink containing a non-aqueous solvent as a main solvent is known as well as a hot melt ink (solid ink) contained in a content. Non-aqueous inks can be classified into solvent inks (solvent-based inks) whose main solvent is a volatile organic solvent and oil-based inks (oil-based inks) whose main solvent is a low-volatile or non-volatile organic solvent. The solvent ink dries on the recording medium mainly by evaporation of the organic solvent, whereas the oil-based ink dries mainly by penetrating into the recording medium.

Since the color material of the ink used in the inkjet recording method is excellent in light resistance, weather resistance, and water resistance required for high-quality printing, the number of inks using a pigment as a color material tends to increase.
In addition, color printing is usually performed by a three-color ink set containing three primary colors of reduced color mixing, yellow (Y), magenta (M), and cyan (C), or black (K). Various hues are expressed by using a four-color ink set in which the above is added.
In color printing, multiple colors of ink are applied on top of each other to reproduce the colors, so the total amount of ink applied to the paper surface increases and the image falls out to the back side of the paper surface, the so-called strike-through phenomenon. Can be a problem. Further, when the total amount of ink applied on the paper surface is large, there is a problem that the saturation of the printed matter is lowered. Further, in the case of mainly performing monochromatic color printing, the method of reproducing a monochromatic color using a plurality of colors of ink may increase the amount of ink used, which may cause an economical problem.

For example, as a color printing method using a plurality of color inks, in Patent Document 1, the oil-based ink (A) containing a dyed rake pigment is printed as a printing medium before the oil-based ink (B) containing a pigment other than the dyed rake pigment. It has been proposed to improve both high color development and reduction of strike-through in printed matter by ejecting it upward.

On the other hand, as a single color ink, for example, there is a demand for a bluish color tone such as a printed matter produced by a diazo copying machine. Such bluish color cannot be sufficiently reproduced only with the conventional cyan-based ink, and it is necessary to superimpose inks of various colors such as magenta, cyanide, and black together with the cyan-based ink.

It has been proposed that inks for color printing include various pigments (Patent Documents 2 and 3). In this case, various pigments are often used alone, and when a plurality of types are combined, pigments having similar colors are often used in combination.

Patent Document 4 proposes a non-aqueous inkjet ink containing a xanthene pigment, an organic solvent, and a dispersant in order to obtain a printed matter having high density and high saturation even with a small ejection amount. Further, Patent Document 1 proposes that the saturation of printed matter by magenta ink is improved by using an azolake pigment together with a xanthene pigment.

Patent Document 5 proposes to provide a highly saturated vermilion printed matter by using a non-aqueous inkjet ink containing a watching red pigment and a yellow benzimidazolone pigment as pigments.

JP-A-2015-127104 Japanese Unexamined Patent Publication No. 2005-298585 JP-A-2007-197500 Japanese Unexamined Patent Publication No. 2014-19766 Japanese Patent No. 6002760

A bluish color tone such as that of printed matter printed by a diazo copying machine cannot be sufficiently obtained by simply using conventional cyan ink. Further, even if two or more kinds of cyanide pigments are used in combination as the ink pigment, the color tone cannot be sufficiently adjusted. Further, when a pigment having a different color is used together with the cyan pigment as the ink pigment, a problem may occur in the dispersion stability of the pigment. Since pigments have different structures and surface treatments, or different particle sizes, if two types of pigments are used in one ink, the dispersion state of the pigments will change and the storage stability will deteriorate. The color may change.

One object of the present invention is to provide a blue-based oil-based pigment ink in which a printed matter has a high image density and the ink has good storage stability.

The gist of the present invention is as follows.
(1) An oil-based pigment ink containing a phthalocyanine blue pigment, a xanthene red pigment, and a non-aqueous solvent, wherein the phthalocyanine blue pigment and the xanthene red pigment have a mass ratio of 55:45 to 95: 5.
(2) The oil-based pigment ink according to (1), wherein the phthalocyanine blue pigment and the xanthene red pigment have a mass ratio of 65:35 to 85:15.
(3) The xanthene-based red pigment is C.I. I. The oil-based pigment ink according to (1) or (2), which is Pigment Red 81: 4.
(4) The phthalocyanine blue pigment is C.I. I. Pigment Blue 15: 3 and / or C.I. I. The oil-based pigment ink according to any one of (1) to (3), which is Pigment Blue 15: 4.

(5) The β-oxynaphthoic acid-based azolake-based red pigment is further contained, and the β-oxynaphthoic acid-based azolake-based red pigment is 0.1 parts by mass to 4 parts by mass with respect to 10 parts by mass of the xanthene-based red pigment. , The oil-based pigment ink according to any one of (1) to (4).
(6) The β-oxynaphthoic acid-based azolake-based red pigment is C.I. I. The oil-based pigment ink according to (5), which has a Pigment Red 57: 1.
(7) The oil-based pigment ink according to any one of (1) to (6), which is an inkjet ink.

According to the present invention, it is possible to provide a blue-based oil-based pigment ink in which the printed matter has a high image density and the ink has good storage stability.

Hereinafter, the present invention will be described using one embodiment. The illustrations in the following embodiments do not limit the invention.
The oil-based pigment ink according to one embodiment (hereinafter, may be simply referred to as ink) contains a phthalocyanine-based blue pigment, a xanthene-based red pigment, and a non-aqueous solvent, and includes a phthalocyanine-based blue pigment and a xanthene-based red pigment. It is characterized in that the mass ratio is 55:45 to 95: 5.
According to this, it is possible to provide a blue-based oil-based pigment ink in which the printed matter has a high image density and the ink has good storage stability.
The printed matter produced by this ink can exhibit a desired color. Specifically, the printed matter produced by this ink can exhibit a bluish color tone similar to that printed matter produced by a diazo copier.
Further, the printed matter produced by this ink can exhibit a desired color and improve the light resistance.
This ink can be printed by using various printing methods, and is particularly suitable for the inkjet recording method.

In the printed matter produced by this ink, the hue angle h of the printed image is preferably in the range of 260 to 300 °, more preferably in the range of 270 to 290 °. Within this range, the color reproducibility of the diazo copier can be set to a desired range.
Here, the hue angle h can be obtained from "h = tan ^-1 (b ^* / a ^* )", and a ^* and b ^* indicate the chromaticity index of the L ^* a ^* b ^* color system.

The ink pigment contains at least a phthalocyanine-based blue pigment and a xanthene-based red pigment.
The phthalocyanine-based blue pigment is a pigment having a phthalocyanine skeleton, and a metal-free phthalocyanine-based blue pigment, a metal phthalocyanine-based blue pigment having a central metal, a substitute thereof, or the like can be used.
The metallic phthalocyanine blue pigment has a structure having a metal M at the center of the phthalocyanine skeleton represented by the following general formula (1). Examples of M include copper (Cu), cobalt (Co), aluminum (Al) and the like.

Preferably, a copper phthalocyanine-based blue pigment having a central metal of copper can be used.
The copper phthalocyanine-based blue pigment may be in any crystal type such as α-type crystal, β-type crystal, and ε-type crystal. A β-type crystalline copper phthalocyanine-based blue pigment is preferable.
Further, as the copper phthalocyanine-based blue pigment, a surface-modified one may be used in order to improve the dispersibility. Further, in order to adjust the color tone, a phthalocyanine skeleton in which a hydrogen atom is replaced with a chlorine atom or the like may be used. Further, a pigment obtained by rake-forming soluble copper phthalocyanine with a variu or the like to make it insoluble can be used.

Examples of the phthalocyanine blue pigment include C.I. I. Pigment Blue 15 (α crystal), C.I. I. Pigment Blue 15: 1 (α crystal), C.I. I. Pigment Blue 15: 2 (α crystal), C.I. I. Pigment Blue 15: 3 (β crystal), C.I. I. Pigment Blue 15: 4 (β crystal), C.I. I. Pigment Blue 15: 5 (γ crystal), C.I. I. Pigment Blue 15: 6 (ε crystal), C.I. I. Copper phthalocyanine blue pigments such as Pigment Blue 17 (sulphonized, barium lake); C.I. I. Pigment Blue 16 (metal-free phthalocyanine blue pigment, polycrystalline), C.I. I. Pigment Blue 75 (cobalt phthalocyanine blue pigment), C.I. I. Pigment Blue 79 (aluminum phthalocyanine blue pigment) and the like can be mentioned.
Among them, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 15: 4 can be preferably used.
These may be used alone or in combination of two or more.

Examples of commercially available copper phthalocyanine blue pigments include "FASTOGEN Blue 4RO-2, AR-7, BRF, RSK, FA5380, LA5380, CA5380, FA5375, AE-8, AE-8K" manufactured by DIC Corporation; BASF Japan Co., Ltd. "HELIOGEN BLUE K7090, K6907, D7086, D7092, K6902, L6700F, L6875F, L7081D", etc .; Dainichiseika Kogyo Co., Ltd. 4940, 4973 "and the like.

The xanthene-based red pigment is a kind of dyed lake pigment, and is a pigment having a xanthene skeleton represented by the following structural formula. Examples thereof include a rhodamine-based pigment, a fluorescein-based pigment, and an eosin-based pigment. .. From the viewpoint of color tone, a rhodamine-based pigment is preferable.
The rhodamine-based pigment is a pigment in which the rhodamine-based pigment is insolubilized. Specifically, a pigment in which rhodamine, rhodamine B, rhodamine 6G and the like are insolubilized can be preferably used.

Examples of rhodamine-based pigments include C.I. I. Pigment RED 81 (Rhodamine 6G (PTMA)), C.I. I. Pigment RED 81: 1 (Rhodamine 6G (STMA)), C.I. I. Pigment RED 81: 2 (Rhodamine (SMA)), C.I. I. Pigment RED 81: 3 (Rhodamine (PMA)), C.I. I. Pigment RED 81: 4 (Rhodamine (PTMA) and Rhodamine 6G (tannic acid)), C.I. I. Pigment RED 169 (Rhodamine 6G (CFA)) and the like can be mentioned.
Among them, C.I. I. Pigment RED 81, C.I. I. Pigment RED 81: 4, C.I. I. Pigment RED 169 can be preferably used.
These may be used alone or in combination of two or more.

The phthalocyanine blue pigment and the xanthene red pigment are contained in a mass ratio of 55:45 to 95: 5.
This ratio is more preferably 65:35 to 95: 5, even more preferably 65:35 to 85:15, and even more preferably 70:30 to 80:20.
When the mass ratio of the phthalocyanine blue pigment to the xanthene red pigment is 55:45 or more based on the phthalocyanine blue pigment, the hue angle can be set in the desired range, and the blue color reproducibility, particularly the diazo copying machine. Color reproducibility can be improved. Further, by blending a large amount of phthalocyanine-based blue pigment within this mass ratio, the light resistance can be further improved.

The phthalocyanine-based blue pigment may be contained, for example, in an amount of 0.1 to 20% by mass, preferably 1 to 10% by mass, based on the total amount of the ink.
The xanthene-based red pigment may be contained, for example, in an amount of 0.05 to 10% by mass, preferably 0.5 to 5% by mass, based on the total amount of the ink.

Further, the ink pigment preferably contains β-oxynaphthoic acid-based azolake-based red pigment (BONA azolake-based red pigment). The BONA azolake-based red pigment is a kind of soluble azolake pigment, and is a pigment in which a diazonium compound having a soluble group in its chemical structure is coupled with β-oxynaphthoic acid (BONA) and insolubilized with various metal salts.
As the diazonium compound, for example, a diazonium compound of an aromatic amine having a sulfonic acid group in which a substituent such as a chlorine atom or a methyl group is introduced can be used. As the insolubilizing metal, for example, barium, calcium, strontium, manganese, magnesium and the like can be used.
The structural formula of an example of BONA azolake-based red pigment is shown below. In the following structural formula, R represents a substituent such as a chlorine atom or a methyl group.

The BONA azolake-based red pigment is preferably 0.1 or more, more preferably 0.2 or more, with respect to the xanthene-based red pigment 10 in terms of mass ratio. The mass ratio of the BONA azolake-based red pigment is preferably 4 or less with respect to the xanthene-based red pigment 10.
As a result, the image density can be further increased while keeping the hue angle in a desired range.

Examples of the BONA azolake-based red pigment include C.I. I. Pigment Red 48, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 48: 2, C.I. I. Pigment Red 48: 3, C.I. I. Pigment Red 48: 4, C.I. I. Pigment Red 48: 5, C.I. I. Pigment Red 52: 1, C.I. I. Pigment Red 52: 2, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 58, C.I. I. Pigment Red 58: 1, C.I. I. Pigment Red 58: 2, C.I. I. Pigment Red 58: 3, C.I. I. Pigment Red 58: 4, C.I. I. Pigment Red 63, C.I. I. Pigment Red 63: 1, C.I. I. Pigment Red 63: 2, C.I. I. Pigment Red 63: 3, C.I. I. Pigment Red 64: 1, C.I. I. Pigment Red 200 and the like can be mentioned.
Among them, C.I. I. Pigment Red 57: 1 can be preferably used.
These may be used alone or in combination of two or more.

The BONA azolake-based red pigment may be contained, for example, in an amount of 0.02 to 5% by mass, preferably 0.1 to 2% by mass, and more preferably 0.1 to 1% by mass, based on the total amount of the ink. is there.

The ink may contain other pigments as long as the effects of the present invention are not impaired. In order to control the hue angle, other pigments may be limited to 1% by mass or less, particularly 0.5% by mass or less.
The average particle size of each of the above pigments is preferably 300 nm or less, more preferably 200 nm or less, from the viewpoint of discharge stability and storage stability.

In order to stably disperse the pigment in the ink, a pigment dispersant can be used together with the pigment.
Examples of the pigment dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high-molecular-weight acid ester, a salt of a high-molecular-weight polycarboxylic acid, a salt of a long-chain polyaminoamide and a polar acid ester, and a high-molecular-weight unsaturated acid. Esters, copolymers of vinylpyrrolidone and long-chain alkene, modified polyurethanes, modified polyacrylates, polyether ester-type anionic activators, polyoxyethylene alkyl phosphates, polyester polyamines and the like are preferably used.

Examples of commercially available pigment dispersants include "Antalon V216 (vinylpyrrolidone / hexadecene copolymer)" and V220 (vinylpyrrolidone / eikosen copolymer) "manufactured by ISP Japan Co., Ltd. (both are commercial products. Name);
"Solsperse 13940 (polyester amine type), 16000, 17000, 18000 (fatty acid amine type), 11200, 24000, 28000" manufactured by Japan Lubrizol Co., Ltd. (all trade names);
"Fuka 400, 401, 402, 403, 450, 451, 453 (modified polyacrylate), 46, 47, 48, 49, 4010, 4055 (modified polyurethane)" manufactured by BASF Japan Ltd. (all trade names);
"Disparon KS-860, KS-873N4 (polyester amine salt)" manufactured by Kusumoto Kasei Co., Ltd. (both trade names);
Dai-ichi Kogyo Seiyaku Co., Ltd. "Discol 202, 206, OA-202, OA-600 (multi-chain polymer nonionic)" (all trade names);
"DISPERBYK101, 155, 9077" manufactured by Big Chemie Japan Co., Ltd. (both product names);
Examples thereof include "Hypermer KD2, KD3, KD11, KD12" (all trade names) manufactured by Croda Japan Co., Ltd.
The pigment dispersant may be appropriately set as long as the amount of the pigment can be sufficiently dispersed in the ink. For example, the pigment dispersant can be blended in a mass ratio of 0.1 to 5 with respect to the pigment 1, preferably 0.1 to 1. The pigment dispersant can be blended in an amount of 0.01 to 10% by mass, preferably 0.01 to 5% by mass, based on the total amount of the ink.

As the non-aqueous solvent, either a non-polar organic solvent or a polar organic solvent can be used. In the present embodiment, it is preferable to use a water-insoluble organic solvent that does not uniformly mix with the same volume of water at 1 atm and 20 ° C. as the non-aqueous solvent.

As the non-polar organic solvent, for example, petroleum-based hydrocarbon solvents such as aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents can be preferably mentioned.
Examples of the aliphatic hydrocarbon solvent and the alicyclic hydrocarbon solvent include non-aqueous solvents such as paraffin-based, isoparaffin-based, and naphthenic-based solvents. Commercially available products include No. 0 Solvent L, No. 0 Solvent M, No. 0 Solvent H, Cactus Normal Paraffin N-10, Cactus Normal Paraffin N-11, Cactus Normal Paraffin N-12, Cactus Normal Paraffin N-13, and Cactus Normal. Paraffin N-14, Cactus Normal Paraffin N-15H, Cactus Normal Paraffin YHNP, Cactus Normal Paraffin SHNP, Isosol 300, Isosol 400, Teclean N-16, Teclean N-20, Teclean N-22, AF Solvent No. 4, AF Solvent No. 5, AF Solvent No. 6, AF Solvent No. 7, Naftesol 160, Naftesol 200, Naftesol 220 (all manufactured by JX Energy Co., Ltd.); Isopar G, Isopar H, Isopar L, Isopar M, Exol D40, Exol D60, Exol D80, Exol D95, Exol D110, Exol D130 (all manufactured by Tonen General Oil Co., Ltd.); Moresco White P-40, Moresco White P-60, Moresco White P-70, Moresco White P-80, More Paraffin White P-100, Moresco White P-120, Moresco White P-150, Moresco White P-200, Moresco White P-260, Moresco White P-350P (all manufactured by MORESCO Co., Ltd.), etc. It can be preferably mentioned.
Preferred examples of the aromatic hydrocarbon solvent include Grade Alken L, Grade Alken 200P (all manufactured by JX Energy Co., Ltd.), Solbesso 100, Solbesso 150, Solbesso 200, Solbesso 200ND (all manufactured by TonenGeneral Sekiyu Co., Ltd.) and the like. be able to.
The distillation initial distillation point of the petroleum-based hydrocarbon solvent is preferably 100 ° C. or higher, more preferably 150 ° C. or higher, and even more preferably 200 ° C. or higher. The distillation initial distillation point can be measured according to JIS K0066 "Distillation test method for chemical products".

As the polar organic solvent, a fatty acid ester solvent, a higher alcohol solvent, a higher fatty acid solvent and the like can be preferably mentioned.
For example, isononyl isononanoate, isodecyl isononanoate, isotridecyl isononanoate (22 carbon atoms), 2-ethylhexyl isooctanoate (16 carbon atoms), methyl laurate, isopropyl laurate, hexyl laurate, isopropyl myristate, isopropyl palmitate, Hexyl palmitate, isooctyl palmitate, isostearyl palmitate, methyl oleate, ethyl oleate, isopropyl oleate, butyl oleate, hexyl oleate, methyl linoleate, ethyl linoleate, isobutyl linoleate, butyl stearate, stearer Hexyl acid, isooctyl stearate, isopropyl isostearate, 2-octyldecyl pivalate, methyl soybean oil, isobutyl soybean oil, methyl tall oil, isobutyl tall oil, etc. have 13 or more carbon atoms in one molecule, preferably 16 to 30 carbon atoms. Fatty acid ester solvent;
Higher grades with 6 or more carbon atoms in one molecule, such as isomiristyl alcohol, isopalmityl alcohol, isostearyl alcohol, 1-octadecanol, oleyl alcohol, isoeicosyl alcohol, and decyltetradecanol, preferably 12 to 20 Alcohol-based solvent;
Higher fatty acid-based solvents such as lauric acid, isomyristic acid, palmitic acid, isoparmitic acid, α-linolenic acid, linoleic acid, oleic acid, isostearic acid, etc., which have 12 or more carbon atoms in one molecule, preferably 14 to 20 carbon atoms. Can be mentioned.
The boiling point of a polar organic solvent such as a fatty acid ester solvent, a higher alcohol solvent, or a higher fatty acid solvent is preferably 150 ° C. or higher, more preferably 200 ° C. or higher, and further preferably 250 ° C. or higher. preferable. The non-aqueous solvent having a boiling point of 250 ° C. or higher also includes a non-aqueous solvent having a boiling point.

These non-aqueous solvents may be used alone, or may be used in combination of two or more as long as they form a single phase.
The oil-based pigment ink preferably has a non-volatile content of 1 to 40% by mass. It is advisable to adjust the blending amount of the ink solvent so as to obtain this non-volatile content.

In addition to the above components, the oil-based pigment ink may contain various additives as long as the effects of the present invention are not impaired. As the additive, a nozzle clogging inhibitor, an antioxidant, a conductivity adjuster, a viscosity adjuster, a surface tension adjuster, an oxygen absorber and the like can be appropriately added. These types are not particularly limited, and those used in the art can be used.

The ink can be produced by mixing each component including a coloring material and a non-aqueous solvent. Preferably, each component can be collectively or divided, mixed and stirred to prepare an ink. Specifically, all the components can be collectively or divided and dispersed in a disperser such as a bead mill, and if desired, can be prepared by passing through a filter such as a membrane filter. The membrane filter can remove 1 to 20 μm of insoluble impurities.

As a printing method using an oil-based pigment ink, for example, it can be used as a general printing ink such as inkjet printing, offset printing, stencil printing, and gravure printing. In particular, it is preferable to use it as an inkjet ink because it has good dispersion stability.
The method of inkjet printing is not particularly limited, and any method such as a piezo method, an electrostatic method, or a thermal method may be used. When an inkjet recording device is used, it is preferable to eject the ink according to the present embodiment from the inkjet head based on a digital signal so that the ejected ink droplets adhere to the recording medium.

When used as an inkjet ink, the viscosity of the oil-based pigment ink varies depending on the nozzle diameter of the ejection head of the inkjet recording system, the ejection environment, etc., but is generally preferably 5 to 30 mPa · s at 23 ° C. , 5 to 15 mPa · s, more preferably about 10 mPa · s.

In the present embodiment, the recording medium is not particularly limited, and a printing paper such as plain paper, coated paper, special paper, cloth, an inorganic sheet, a film, an OHP sheet, etc. are used as a base material and an adhesive layer is formed on the back surface. An adhesive sheet or the like provided with the above can be used. Among these, printing paper such as plain paper and coated paper can be preferably used from the viewpoint of ink permeability.

Here, the plain paper is a paper in which an ink receiving layer, a film layer, or the like is not formed on the ordinary paper. Examples of plain paper include high-quality paper, medium-quality paper, PPC paper, stencil paper, recycled paper, and the like. Plain paper is a paper in which ink easily permeates because paper fibers having a thickness of several μm to several tens of μm form voids of several tens to several hundreds of μm.

Further, as the coated paper, an inkjet coated paper such as matte paper, glossy paper, or semi-glossy paper, or so-called coated printing paper can be preferably used. Here, the coating printing paper is a printing paper that has been conventionally used for letterpress printing, offset printing, gravure printing, etc., and has an inorganic pigment such as clay or calcium carbonate on the surface of high-quality paper or medium-quality paper. , A printing paper provided with a coating layer using a paint containing a binder such as starch. Coated printing paper can be used for finely coated paper, high-quality lightweight coated paper, medium-quality lightweight coated paper, high-quality coated paper, medium-quality coated paper, art paper, cast-coated paper, etc., depending on the amount of paint applied and the coating method. being classified.

Hereinafter, the present invention will be described in detail with reference to Examples. The present invention is not limited to the following examples.
"Making ink"
The ink formulations are shown in Tables 1 and 2. If the dispersant contains a solvent, the solids are shown in parentheses.
Ink raw materials were mixed at the blending ratios shown in each table, zirconia beads (diameter 0.5 mm) were added, and the mixture was dispersed for 120 minutes by a locking mill (manufactured by Seiwa Giken Co., Ltd.). After dispersion, the zirconia beads were removed and filtered through a 3.0 μm and 0.8 μm membrane filter in order to remove dust and coarse particles to obtain an ink.

The components used are as follows.
(Blue pigment)
Phthalocyanine P. B. 15: 3: "FASTOGEN Blue LA5380" manufactured by DIC Corporation.
Phthalocyanine P. B. 15: 4: "LIONOL BLUE FG-7400-G" manufactured by Toyo Color Co., Ltd.
Triphenylmethane P. B. 1: "1000 Fast Blue Conc" manufactured by Inagawa Pigment Co., Ltd.
(Red pigment)
Xanthene P. R. 81: 4: "No9310 Pink" manufactured by Daido Kasei Kogyo Co., Ltd.
Xanthene P. R. 81: "108 Fast Rose Pink" manufactured by Inagawa Pigment Co., Ltd.
Xanthene P. R. 169: "Fanal Pink D4810" manufactured by BASF Japan Ltd.
BONA Azo Lake P.M. R. 57: 1: "SYMULER Brilliant Carmine 6B 400S" manufactured by DIC Corporation.
Quinacridone P. R. 122: "FASTOGEN Super Magenta RG" manufactured by DIC Corporation.

(Pigment dispersant)
S17000: "Solsperse 17000" manufactured by Japan Lubrizol Co., Ltd., solid content 100% by mass.
Disperbyk-101: "Disperbyk-101" manufactured by Big Chemie Japan Co., Ltd., solid content 70% by mass.
(solvent)
Isopropyl palmitate: "Exepearl IPP" manufactured by Kao Corporation.
Isotridecyl isononanoate: "Saracos 913" manufactured by Nisshin Oillio Group Co., Ltd.
Octadecanol: "1-Octadecanol" manufactured by Tokyo Chemical Industry Co., Ltd.
AF-4: "AF Solvent No. 4" manufactured by JX Nippon Oil & Energy Co., Ltd.

"Evaluation"
The inks of the above Examples and Comparative Examples were evaluated by the following methods. The results of these evaluations are shown in each table.

(Diazo copier color reproducibility (hue angle))
Each ink was loaded into an inkjet printer "Orphis EX9050", and a solid image of 12 pl per pixel was printed on plain paper (Ideal Paper Multi, manufactured by Riso Kagaku Corporation) at a resolution of 300 dpi x 300 dpi.
One day after the print production, the hue angle of the image portion described in the printed matter was measured with "X-Rite eXact" manufactured by Videojet X-Rite. The measurement results were evaluated according to the following criteria.
Hue angle h = tan ^-1 (b ^* / a ^* )
A: h is from 270 ° or more to less than 290 °.
B: h is in the range of 260 ° or more and less than 270 ° or 290 ° or more and less than 300 °.
C: h is in the range of less than 260 ° or more than 300 °.

(Image density)
A printed matter was produced in the same manner as in the evaluation of the color reproducibility of the diazo copier. After printing, the image density of the printed matter was visually observed. Evaluation was made based on the following criteria.
A: The printed matter image feels dark enough. It feels darker than the image density of Example 1.
B: The printed matter image does not feel dark. It feels the same as or slightly lighter than the image density of Example 1.

(Storage stability)
First, the viscosity of the ink immediately after the ink was produced was measured.
Next, the ink was placed in a closed container and left at 70 ° C. for 4 weeks. Then, the ink was sampled and the ink viscosity was measured.
The ink viscosity was the viscosity at 23 ° C., and was measured using a "rheometer MCR302" manufactured by Anton Pearl Japan Co., Ltd. at a cone angle of 1 ° and a diameter of 50 mm.
From the ink viscosity before and after leaving for 4 weeks, the viscosity change rate was determined by the following formula, and the storage stability was evaluated according to the following criteria.
Viscosity change rate (%) = [(Viscosity after 4 weeks (mPa · s) × 100) / (Initial value of viscosity (mPa · s))] -100 (%)
A: The viscosity change rate is less than 5%.
B: The viscosity change rate is 5% or more and less than 10%.
C: The viscosity change rate is 10% or more.

(Light resistance)
A printed matter was produced in the same manner as in the evaluation of the color reproducibility of the diazo copier. One day after the production of the printed matter, the printed matter was subjected to an accelerated test of the printed matter under the following conditions using a "weatherometer Ci4000" manufactured by Atlas.
Before and after the accelerated test, the hue of the printed matter was visually observed and compared. Evaluation was made based on the following criteria.
Acceleration evaluation conditions ・ Irradiance control 300-400 nm ・ Lamp xenon lamp ・ Irradiance 36 W / m ²・ Irradiance time 168 hours

A: The hue does not change much.
B: Hue changes slightly.
C: The hue is clearly different.

As shown in each table, with the inks of each example, it was possible to obtain a hue angle range excellent in color reproducibility of the diazo copier. In addition, the inks of each example were excellent in image density, storage stability, and light resistance.
Further, in the ink of each example, the initial viscosity was in the range of 5 to 15 mPa · s, and the viscosity was appropriate.

Throughout Examples 1-9, good results could be obtained using various pigments, pigment dispersants, and solvents.
Through Examples 1, 6 to 8, the hue angle can be made more desired by setting the phthalocyanine blue pigment: xanthene red pigment to 65: 35 to 85:15 based on the phthalocyanine blue pigment. It was. Further, when the phthalocyanine blue pigment: xanthene red pigment was 65:35 or more based on the phthalocyanine blue pigment, the light resistance was further improved.
In Example 9, in addition to the phthalocyanine blue pigment and the xanthene red pigment, a BONA azolake red pigment was used, and the concentration could be further improved.

In Comparative Example 1, the phthalocyanine blue pigment was used alone, and the hue angle could not be controlled within a desired range.
In Comparative Example 2, a triphenylmethane-based pigment was used as the blue pigment and a xanthene-based red pigment was used as the red pigment, and the hue angle could not be controlled within a desired range. Further, in Comparative Example 2, storage stability and light resistance were not sufficiently obtained.
In Comparative Example 3, a phthalocyanine-based blue pigment and a quinacridone-based red pigment were used in combination, and the dispersibility of the ink was poor, and sufficient results could not be obtained.
In Comparative Example 4, the phthalocyanine blue pigment and the BONA azolake red pigment were combined, the hue angle could not be controlled within a desired range, and the storage stability could not be sufficiently obtained.
In Comparative Example 5, in the combination of the phthalocyanine blue pigment and the xanthene red pigment, the proportion of the xanthene red pigment was large, and the hue angle could not be controlled within a desired range.

Claims (7)

An oil-based pigment ink containing a phthalocyanine blue pigment, a xanthene red pigment, and a non-aqueous solvent, wherein the phthalocyanine blue pigment and the xanthene red pigment have a mass ratio of 55:45 to 95: 5. The oil-based pigment ink according to claim 1, wherein the phthalocyanine-based blue pigment and the xanthene-based red pigment have a mass ratio of 65:35 to 85:15. The xanthene-based red pigment is C.I. I. The oil-based pigment ink according to claim 1 or 2, which is Pigment Red 81: 4. The phthalocyanine blue pigment is C.I. I. Pigment Blue 15: 3 and / or C.I. I. The oil-based pigment ink according to any one of claims 1 to 3, which is Pigment Blue 15: 4. The claim that the β-oxynaphthoic acid-based azolake-based red pigment is further contained, and the β-oxynaphthoic acid-based azolake-based red pigment is 0.1 parts by mass to 4 parts by mass with respect to 10 parts by mass of the xanthene-based red pigment. The oil-based pigment ink according to any one of 1 to 4. The β-oxynaphthoic acid-based azolake-based red pigment is C.I. I. The oil-based pigment ink according to claim 5, which is Pigment Red 57: 1. The oil-based pigment ink according to any one of claims 1 to 6, which is an inkjet ink.