JP2018100372A - Oil-based inkjet ink - Google Patents

Abstract

Provided is an oil-based inkjet ink that has excellent saturation and can reduce bleeding and back-through. An oil-based inkjet ink comprising a dyed lake pigment, a pigment dispersant, a solvent A, and a solvent B, wherein the solvent A has a Hansen solubility parameter δ of 11 (cal / cm 3) 1. , And the hydrogen bond term δh is 2 (cal / cm 3) 1/2 or more, the solvent B has a Hansen solubility parameter δ of 11 (cal / cm 3) 1/2 or more, An oil-based inkjet ink having a hydrogen bond term δh of 2 (cal / cm 3) 1/2 or more and a boiling point of 150 ° C. or less. [Selection figure] None

Description

  The present invention relates to an oil-based inkjet ink.

  The ink jet recording method is a method in which ink jet ink having high fluidity is ejected as droplets from fine nozzles, and an image is recorded on a recording medium placed facing the nozzles, and high speed printing can be performed with low noise. Therefore, it has been spreading rapidly in recent years. As an ink used in such an ink jet recording method, an aqueous ink containing water as a main solvent, an ultraviolet curable ink (UV ink) containing a polymerizable monomer as a main component and a high content, and a wax as a main component are high. A so-called non-aqueous ink containing a non-aqueous solvent as a main solvent together with hot-melt ink (solid ink) contained in a content is known. Non-aqueous inks can be classified into solvent ink (solvent ink) whose main solvent is a volatile organic solvent, and oil ink (oil ink) whose main solvent is a low-volatile or nonvolatile organic solvent. The oil-based ink is dried mainly by penetrating into the recording medium.

  Patent Document 1 includes a pigment and a solvent as an inkjet ink with reduced toner solubility and excellent on-machine stability. 30 to 70% by weight of the solvent is a nonpolar solvent, and 20% by weight or more of the solvent is more than 20% by weight. An inkjet ink comprising an ester solvent having an α value of 6 ° to 8 ° is disclosed.

JP 2007-126564 A

  In a non-aqueous ink, when a dyed lake pigment is used as a coloring material, the color development of the ink is improved and an image with high saturation is easily formed.

  However, in an inkjet ink using a dyed lake pigment, if a non-polar organic solvent having a high polarity is used, bleeding may occur or worsen in the printed matter. On the other hand, in an inkjet ink using a dyed lake pigment, if only a low-polarity non-aqueous organic solvent is used, there is a case where the printout of the printed matter occurs or deteriorates.

  Accordingly, an object of the present invention is to provide an oil-based inkjet ink that is excellent in saturation and can reduce bleeding and back-through.

  One aspect of the present invention relates to the following oil-based inkjet ink.

<1> An oil-based inkjet ink comprising a dyed lake pigment, a pigment dispersant, a solvent A, and a solvent B,
The solvent A has a Hansen solubility parameter δ of less than 11 (cal / cm ³ ) ^1/2 and a hydrogen bond term δ _h of 2 (cal / cm ³ ) ^1/2 or more,
The solvent B has a Hansen solubility parameter δ of 11 (cal / cm ³ ) ^1/2 or more, a hydrogen bond term δ _h of 2 (cal / cm ³ ) ^1/2 or more, and a boiling point. 150 ° C. or less,
Oil-based inkjet ink.
<2> The oil-based inkjet ink according to <1>, wherein the content of the solvent A is 80% by mass or less of the total amount of the oil-based inkjet ink.
<3> The solvent A includes at least one solvent selected from the group consisting of a fatty acid ester solvent, a higher alcohol solvent having 6 or more carbon atoms, and a higher fatty acid solvent having 12 or more carbon atoms. Or the oil-based inkjet ink as described in <2>.
<4> The oily property according to any one of <1> to <3>, wherein the solvent B includes at least one solvent selected from the group consisting of water, acetonitrile, and an alcohol having 1 to 5 carbon atoms. Inkjet ink.
<5> The oil-based inkjet ink according to any one of <1> to <4>, wherein the content of the solvent B is 0.05% by mass to 5% by mass with respect to the total amount of the oil-based inkjet ink.
<6> The solubility parameter δ of Hansen is less than 11 (cal / cm ³ ) ^1/2 and further includes a solvent having a hydrogen bond term δ _h of less than 2 (cal / cm ³ ) ^1/2. The oil-based inkjet ink according to any one of 1> to <5>.

  According to the present invention, it is possible to provide an oil-based inkjet ink that has excellent saturation and can reduce bleeding and back-through.

  Although one embodiment of the present invention is described below, the present invention is not limited to the following embodiment.

  The oil-based inkjet ink of the embodiment (hereinafter sometimes referred to as “ink” or “oil-based ink”) includes a dyed lake pigment, a pigment dispersant, a solvent A, and a solvent B.

The oil-based inkjet ink of the embodiment includes a dyed lake pigment as a coloring material. By including a dyed lake pigment, it is easy to improve the saturation of the printed matter.
The dyed lake pigment is obtained by pigmentizing a dye. Specifically, the dye lake is insolubilized using a precipitating agent and fixed to an extender pigment. Examples of dyed lake pigments include those using acidic dyes and those using basic dyes.

  An acidic dye is a pigment acid having an acidic group such as a sulfo group or a carboxyl group in the molecule, and a commercially available one is an alkali salt thereof and is water-soluble. For a dyed lake pigment using an acid dye, for example, a metal salt such as Al, Ca, Ba or the like can be used as a precipitant.

Examples of red acid dyes include eosin, acid phloxine, and erythrosine. Examples of dye lake lakes using red acid dyes include C.I. I. Pigment red 90, C.I. I. And CI Pigment Red 90: 1.
Examples of the orange-based acid dye include Orange II, and examples of the dyed lake pigment using the orange-based acid dye include C.I. I. Pigment orange 17 and the like.
Examples of the dyed lake pigment using a blue acid dye include peacock blue lake and alkali blue lake.

  The basic dye is a dye that has a basic group such as an amino group or a derivative thereof in its structure and becomes a cation in an aqueous solution. Examples of basic dyes include anthraquinone dyes, rhodamine dyes, diphenylmethane dyes, triphenylmethane dyes, azo dyes, xanthene dyes, methine dyes, and the like.

For dyed lake pigments using basic dyes, use an acidic substance such as tannic acid, phosphotungstic acid, phosphomolybdic acid, phosphotungsten / molybdic acid, or synthetic mordants (Katanol, Tamol) as a precipitant. Can do.
A basic dyed lake pigment obtained by using a mordant called a complex acid such as phosphotungstic acid, phosphomolybdic acid, phosphotungstic acid or molybdic acid as a precipitant is called a final color. The final color has good light resistance and chemical resistance, and has a high tinting strength.

Examples of the basic dye include rhodamine 6GCP, rhodamine B, and rhodamine 123.
Examples of dyed lake pigments using basic dyes include rhodamine lake B (CI Pigment Violet 1), C.I. I. Pigment red 169, C.I. I. Pigment red 81, C.I. I. Pigment red 81: 4, C.I. I. Pigment red 173, methyl violet lake, malachite green lake and the like.
Examples of dyed lake pigments using complex acid as a precipitating agent include C.I. I. Pigment red 81: 4.

  These dyed lake pigments may be used alone or in combination of two or more.

  The average particle size of the dyed lake pigment is preferably 300 nm or less, more preferably 150 nm or less, and still more preferably 100 nm or less, from the viewpoint of ejection stability and storage stability. The average particle diameter of the dyed lake pigment may be, for example, 20 nm or more.

  The content of the dyed lake pigment in the oil-based inkjet ink is not particularly limited, but may be usually 0.01 to 20% by mass relative to the total amount of the ink, and 1 to 15% by mass from the viewpoint of printing density and ink viscosity. Preferably, it is 5 to 10% by mass.

In addition to the dyed lake pigment, other colorants such as pigments and / or dyes other than the dyed lake pigment may be used as the color material.
As pigments other than dyed lake pigments, organic pigments such as azo pigments, phthalocyanine pigments, and polycyclic pigments, and inorganic pigments can be used. Examples of the azo pigment include a soluble azo lake pigment, an insoluble azo pigment, and a condensed azo pigment. Examples of phthalocyanine pigments include metal phthalocyanine pigments and metal-free phthalocyanine pigments. Polycyclic pigments include quinacridone pigments, perylene pigments, perinone pigments, isoindoline pigments, isoindolinone pigments, dioxazine pigments, thioindigo pigments, anthraquinone pigments, quinophthalone pigments, metal complex pigments. And diketopyrrolopyrrole (DPP). Representative examples of inorganic pigments include carbon black and titanium oxide. These pigments may be used alone or in combination of two or more.

  As dyes, azo dyes, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes, quinoneimine dyes, xanthene dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, phthalocyanine dyes, Mention may be made of oil-soluble dyes such as metal phthalocyanine dyes. These dyes may be used alone or in combination of two or more.

  As the coloring material, in addition to the dyed lake pigment, when using another coloring material, the content of the dyed lake pigment in the oil-based inkjet ink is preferably 30% by mass or more based on the whole coloring material, 50 mass% or more is more preferable. The content of the dyed lake pigment in the oil-based inkjet ink may be 100% by mass with respect to the entire color material.

  In order to improve the dispersion of the pigment in the oil-based ink, it is preferable to contain a pigment dispersant. The pigment dispersant is not particularly limited as long as it can stably disperse the pigment in a non-aqueous solvent. Examples thereof include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, and a high molecular weight polycarboxylic acid. Salt of acid, salt of long chain polyaminoamide and polar acid ester, high molecular weight unsaturated acid ester, copolymer of vinylpyrrolidone and long chain alkene, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, Polyoxyethylene alkyl phosphate ester, polyester polyamine and the like are preferably used.

  Commercially available pigment dispersants include “ANTALON V216 (vinyl pyrrolidone / hexadecene copolymer)” (trade name) manufactured by ISP Japan, “Solsperse 13940 (polyesteramine type) manufactured by Nippon Lubrizol Corporation. ), 17000, 18000 (fatty acid amine series), 11200, 24000, 28000 "(all trade names)," EFCA 400, 401, 402, 403, 450, 451, 453 (modified polyacrylate) "manufactured by BASF Japan Ltd., 46, 47, 48, 49, 4010, 4055 (modified polyurethane) "(all trade names)," Disparon KS-860, KS-873N4 (polyester amine salt) "manufactured by Enomoto Kasei Co., Ltd. (all trade names) Manufactured by Daiichi Kogyo Seiyaku Co., Ltd. 206, OA-202, OA-600 (multi-chain polymeric nonionic) "(all trade names).

  The pigment dispersant is preferably contained in a mass ratio of 0.2 to 1.0 with respect to the pigment 1. The content of the pigment dispersant in the total amount of ink is preferably 0.5 to 15% by mass, and more preferably 1 to 5% by mass.

  Further, a pigment derivative may be contained in order to improve the dispersion of the pigment in the oil-based ink. Any pigment derivative may be used as long as a polar functional group is introduced into the pigment skeleton. Examples of the pigment derivative include a skeleton of a pigment such as phthalocyanine, azo, anthraquinone, quinacridone, carboxyl group, sulfonic acid group, amino group, nitro group, acid amide group, carbonyl group, carbamoyl group, phthalimide group. , A group to which a functional group such as a sulfonyl group is added, and a salt thereof can be preferably used.

The solvent A and the solvent B will be described.
The solvent A has a Hansen solubility parameter δ of less than 11 (cal / cm ³ ) ^1/2 and a hydrogen bond term δ _h of 2 (cal / cm ³ ) ^1/2 or more. Solvent B has a Hansen solubility parameter δ of 11 (cal / cm ³ ) ^1/2 or more, a hydrogen bond term δ _h of 2 (cal / cm ³ ) ^1/2 or more, and a boiling point of 150 It is below ℃.

The Hansen solubility parameter δ and the hydrogen bond term δ _h will be described.
The Hansen solubility parameter (hereinafter sometimes referred to as “HSP”) is a three-dimensional solubility parameter proposed by Hansen in 1967.
Hansen's solubility parameter is obtained by dividing the solubility parameter introduced by Hildebrand into three components of a dispersion term δ _d , a polar term δ _p , and a hydrogen bond term δ _h and expressed in a three-dimensional space. The dispersion term indicates the effect due to the dispersion force, the polarity term indicates the effect due to the force between the dipoles, and the hydrogen bond term indicates the effect due to the hydrogen bond force. More specifically, POLYMER HANDBOOK. FOURTH EDITION. (Editors. J. BRANDRUP, E. H. IMMERGUT, and E. A. GRULKE.) And the like.

Hansen solubility parameters can be determined from experiments or calculations. Here, the Hansen solubility parameter δ and the hydrogen bond term δ _h are values calculated by a method using constants proposed by Van Keveren and Hofsizeer described below. In this method, the dispersion term δ _d , the polar term δ _p , and the hydrogen bond term δ _h are considered to depend on the type and number of substituents, and are calculated by the following equations (1) to (3), respectively. The The Hansen solubility parameter δ is calculated by the equation (4) based on the values of the dispersion term δ _d , the polar term δ _p , and the hydrogen bond term δ _h obtained by the equations (1) to (3). Is done. In the following formulas (1) to (3), V is a molar volume (cm ³ / mol). F _di , F _pi, and E _hi are constants depending on the substituents, respectively, “Based on solubility parameter application examples—mechanism and evaluation / calculation examples of solubility”, Information Organization, 2007 3 On the 15th of May, the numerical values described in Table 2, “Parameters for calculating SP values by the Hofizer-VanKrevelen method (excerpt)” are used.

The greater the Hansen solubility parameter δ, the higher the polarity. Furthermore, hydrogen bond [delta] _h is the case of 2 or more, polarity somewhat high.
The dyed lake pigment is a pigment in which a dye is insolubilized. The dye is generally water-soluble and has higher affinity and is easily dissolved in a solvent having higher polarity.
In an oil-based ink using a dyed lake pigment, if a highly polar organic solvent is used, the dye derived from the dyed lake pigment may be dissolved in the solvent, and bleeding of the printed matter may occur or worsen. This is because when the dyed lake pigment comes into contact with a highly polar organic solvent, the dye is separated from the dyed lake pigment due to the affinity between the dye and the organic solvent. It is thought to move in the direction.
On the other hand, when the oil-based ink using the dyed lake pigment contains only a low-polar or nonpolar non-aqueous organic solvent having a hydrogen bond term δ _h of less than 2, the dye derived from the dyed lake pigment is dissolved. It can be prevented or reduced. However, in this case, the dyed lake pigment is likely to move in the penetration direction together with the solvent, and there is a case in which the printed film is exposed or deteriorated.

Both the solvent A and the solvent B have a hydrogen bond term δ _h of 2 or more and a relatively high polarity, but the solvent B has a Hansen solubility parameter δ higher than that of the solvent A 11 (cal / cm ³ ) ^1/2 or more. In addition, the solvent B has a boiling point of 150 ° C. or less and is relatively volatile.
By using the solvent B together with the solvent A in the oil-based ink containing the dyed lake pigment, the dye tends to have a higher affinity with the solvent B having a Hansen solubility parameter δ than the solvent A. In addition, since the solvent B has a boiling point of 150 ° C. or less and thus volatilizes immediately from the printed material, the amount of the solvent B transferred in the printed material is small. That is, since the ink contains the solvent B together with the solvent A, even if the dye is separated from the dyed lake pigment, the separated dye moves with the solvent B rather than the solvent A. In addition, since the dye has a sufficient time to be fixed on the paper fiber before the solvent B volatilizes, it is considered that there is little bleeding.
As described above, in the oil-based inkjet ink using the dyed lake pigment, when the solvents A and B are used, bleeding of the printed matter can be reduced. Moreover, the show-through of printed matter can be reduced.

As the solvent A, if the Hansen solubility parameter δ is less than 11 (cal / cm ³ ) ^1/2 and the hydrogen bond term δ _h is 2 (cal / cm ³ ) ^1/2 or more, There is no particular limitation.

As the solvent A, those having a polar functional group are preferable, and preferred examples of the polar functional group include a carboxy group (—COOH), a hydroxy group (—OH), and —COO—.
Examples of the solvent A include fatty acid ester solvents, higher alcohol solvents having 6 or more carbon atoms (more preferably 12 to 20), higher fatty acid solvents having 12 or more carbon atoms (more preferably 14 to 20), and the like. Preferable examples can be given. Of these, fatty acid ester solvents are more preferable.

The fatty acid ester solvent is preferably a fatty acid ester solvent having 13 or more (more preferably 16 to 30) carbon atoms in one molecule. Examples of the fatty acid ester solvent include isononyl isononanoate, isodecyl isononanoate, methyl laurate, isopropyl laurate, hexyl laurate, isopropyl myristate, isopropyl palmitate (HSPδ7.8 (cal / cm ³ ) ^1/2 , Hydrogen bond term δ _h 2.2 (cal / cm ³ ) ^1/2 ), hexyl palmitate, isooctyl palmitate, isostearyl palmitate, methyl oleate, ethyl oleate (HSP δ 7.7 (cal / cm ³ ) ^{1 / 2} , hydrogen bond term δ _h 2.2 (cal / cm ³ ) ^1/2 ), isopropyl oleate, butyl oleate, hexyl oleate, methyl linoleate, ethyl linoleate, isobutyl linoleate, butyl stearate, Hexyl stearate, stearic acid Sooctyl, ethyl isostearate (HSPδ 8.0 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 2.2 (cal / cm ³ ) ^1/2 ), isopropyl isostearate, 2-octyldecyl pivalate, etc. Can be mentioned.
Examples of the higher alcohol solvent having 6 or more carbon atoms include isomyristyl alcohol, isopalmityl alcohol (HSP δ 8.9 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 4.1 (cal / cm ³ ). ^1/2 ), isostearyl alcohol, oleyl alcohol, isoeicosyl alcohol, decyltetradecanol and the like.
Examples of the higher fatty acid solvent having 12 or more carbon atoms include lauric acid, isomyristic acid, palmitic acid, isopalmitic acid, α-linolenic acid, linoleic acid, oleic acid, and isostearic acid (HSPδ8.2 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 2.7 (cal / cm ³ ) ^1/2 ), and the like.
The boiling point of the solvent A is preferably 150 ° C. or higher, more preferably higher than 150 ° C., more preferably 200 ° C. or higher, and further preferably 250 ° C. or higher. The non-aqueous solvent having a boiling point of 250 ° C. or higher includes non-aqueous solvents that do not exhibit a boiling point.

The solvent A may be used alone or in combination of two or more as long as a single phase is formed.
The content of the solvent A in the oil-based inkjet ink is preferably 10% by mass or more, more preferably 30% by mass or more, further preferably 50% by mass or more, and further preferably 60% by mass or more based on the total amount of the ink. Further, the content of the solvent A in the oil-based inkjet ink may be, for example, 95% by mass or less, preferably 90% by mass or less, and more preferably 80% by mass or less based on the total amount of the ink.
The content of the solvent A in the oil-based inkjet ink is preferably 50% by mass or more, more preferably 60% by mass or more of the total amount of the solvent contained in the ink. The content of the solvent A in the oil-based inkjet ink may be, for example, 99.95% by mass or less, 90% by mass or less, and 80% by mass or less with respect to the total amount of the solvent contained in the ink. Good.

As the solvent B, Hansen's solubility parameter δ is 11 (cal / cm ³ ) ^1/2 or more, the hydrogen bond term δ _h is 2 (cal / cm ³ ) ^1/2 or more, and the boiling point is 150 ° C. It will not specifically limit if it is the following.
The boiling point of the solvent B is more preferably 140 ° C. or lower, and further preferably 120 ° C. or lower. The boiling point of the solvent B may be, for example, 50 ° C. or higher.
The solvent B preferably has a viscosity of 10 mPa · s or less at 23 ° C.

Further, the difference between the Hansen solubility parameter δ of the solvent A and the Hansen solubility parameter δ of the solvent B is preferably 2 (cal / cm ³ ) ^1/2 or more, and 3 (cal / cm ³ ). More preferably, it is ^1/2 or more. When the difference between the Hansen solubility parameter δ of the solvent A and the solvent B is 2 (cal / cm ³ ) ^1/2 or more, the affinity between the dye of the dyed lake pigment and the solvent B tends to be higher. Therefore, it is easy to further improve the effect of reducing bleeding.

Examples of the solvent B include water and organic solvents having a polar functional group. Preferred examples of the polar functional group include a carboxyl group (—COOH), a hydroxy group (—OH), and a cyano group (—CN).
Examples of the solvent B include water (HSP δ 23.4 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 20.7 (cal / cm ³ ) ^1/2 , boiling point 100 ° C.), acetonitrile (HSP δ 12.2). (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 3.2 (cal / cm ³ ) ^1/2 , boiling point 82 ° C.), alcohol having 1 to 5 carbon atoms, and the like. Examples of the alcohol include methanol (HSPδ14.5 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 10.8 (cal / cm ³ ) ^1/2 , boiling point 64.7 ° C.), ethanol (HSPδ12.5 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 9.0 (cal / cm ³ ) ^1/2 , boiling point 78.4 ° C.), propanol (HSP δ 11.5 (cal / cm ³ ) ^1/2 , Hydrogen bond term δ _h 8.0 (cal / cm ³ ) ^1/2 , Boiling point 97 ° C.), isopropanol (HSP δ 11.1 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 7.8 (cal / cm ³ ) ^1/2 , boiling point 82 ° C.).

The solvent B may be used alone or in combination of two or more as long as a single phase is formed.
The content of the solvent B in the oil-based inkjet ink is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, and 0.3% by mass with respect to the total amount of the ink. % Or more is more preferable. When the content of the solvent B is within this range, it is easy to further reduce bleeding and breakthrough.
The content of the solvent B in the oil-based inkjet ink is preferably 5% by mass or less, and more preferably 2% by mass or less with respect to the total amount of the ink. When the content of the solvent B is within this range, it is easy to improve the storage stability of the ink.

The oil-based inkjet ink according to the embodiment has a Hansen solubility parameter δ of less than 11 (cal / cm ³ ) ^1/2 and a hydrogen bond term δ _h of less than 2 (cal / cm ³ ) ^1/2 It is preferable that it is further included. Hereinafter, a solvent having a Hansen solubility parameter δ of less than 11 (cal / cm ³ ) ^1/2 and a hydrogen bond term δ _h of less than 2 (cal / cm ³ ) ^1/2 is referred to as “solvent C”. There is a case. When the solvent C is used together with the solvent A and the solvent B, the storage stability of the ink can be further improved.

Preferred examples of the solvent C include petroleum hydrocarbon solvents such as aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents.
Examples of the aliphatic hydrocarbon solvent and the alicyclic hydrocarbon solvent include non-aqueous solvents such as paraffinic, isoparaffinic, and naphthenic solvents, and commercially available products include 0 Solvent L, 0 Solvent M, 0 Solvent H, Cactus normal paraffin N-10, Cactus normal paraffin N-11, Cactus normal paraffin N-12, Cactus normal paraffin N-13, 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, Futezol 160, Naphthezol 200, Naphthezol 220 (all trade names made by JX Nippon Oil & Energy Corporation); Isopar G, Isopar H, Isopar L, Isopar M, Exol D40, Exol D60, Exol D80, Exol D95, Exol D110 And Exol D130 (both are trade names manufactured by TonenGeneral Sekiyu KK) and the like. As the aromatic hydrocarbon solvent, grade alkene L, grade alkene 200P (all are trade names manufactured by JX Nippon Oil & Energy Corporation), Solvesso 100, Solvesso 150, Solvesso 200, Solvesso 200ND (all are TonenGeneral Sekiyu KK) The product name of the product and the like can be preferably mentioned. The distillation initial boiling point of the petroleum 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 boiling point can be measured in accordance with JIS K0066 “Method for Distillation Test of Chemical Products”.

These solvents C may be used alone or in combination of two or more as long as a single phase is formed.
When the oil-based inkjet ink contains the solvent C, the content is not particularly limited, but the content of the solvent C in the ink is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total amount of the ink. 20 mass% or more is more preferable. Further, the content of the solvent C in the ink is preferably 70% by mass or less, more preferably 50% by mass or less, and further preferably 30% by mass or less with respect to the total amount of the ink.

The mass ratio of the solvent A and the solvent C (solvent A: solvent C) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, still more preferably 30:70 to 80:20, 40: 60-80: 20 may be sufficient.
Although not particularly limited, it is preferable that the solvent is blended so that the non-volatile content of the ink is 1 to 40% by mass.

  When the oil-based inkjet ink contains the solvent C, the combination of the solvent A and the solvent C is not particularly limited, but the solvent A preferably contains a fatty acid ester solvent, and the solvent C preferably contains a petroleum hydrocarbon solvent. The total amount of the fatty acid ester solvent and the petroleum hydrocarbon solvent is preferably 50% by mass or more, more preferably 80% by mass or more, and 90% by mass or more or 100% by mass with respect to the total amount of the solvent A and the solvent C. Good. For example, the solvent A and the solvent C of the ink can be composed only of a fatty acid ester solvent and a petroleum hydrocarbon solvent.

The oil-based inkjet ink may contain various additives that are usually used in the field as long as they do not impair the object of the present invention.
Specifically, as an antifoaming agent, a surface tension reducing agent, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or a polymer-based, silicone-based, or fluorine-based surfactant. An agent or the like may be added to the ink.
Further, dibutylhydroxytoluene, propyl gallate, tocopherol, butylhydroxyanisole, nordihydroguaiaretic acid, etc., may be added to the ink as an antioxidant.

The method for preparing the oil-based inkjet ink of the present embodiment is not particularly limited.
The ink can be produced, for example, by mixing or dispersing all components at once or by dividing. For example, a pigment dispersion containing a pigment, a pigment dispersant, and an organic solvent can be prepared first, and further added with an organic solvent and other optional components. Or you may mix all the compounding components at once. As the dispersing means, for example, a ball mill, a bead mill, or the like can be used. After dispersion, if desired, it may be passed through a filter such as a membrane filter.

  The viscosity of the ink when used in an ink jet recording apparatus has a suitable range depending on the nozzle diameter of the ejection head, the ejection environment, and the like, but in general, it is preferably 1 to 30 mPa · s at 23 ° C. It is more preferable that Here, the viscosity represents a value at 23 ° C.

  The manufacturing method of the printed matter using the oil-based inkjet ink of this embodiment is not specifically limited. The method for producing a printed material is preferably, for example, a method including applying the ink of the embodiment to a recording medium by an inkjet recording method. The ink jet recording apparatus to be used may be of any system such as a piezo system, an electrostatic system, or a thermal system. In the case of using an ink jet recording apparatus, for example, the ink of the embodiment may be ejected from an ink jet head based on a digital signal, and the ejected ink droplets may be attached to a recording medium.

  In the present embodiment, the recording medium is not particularly limited, and printing paper such as plain paper, coated paper, special paper, cloth, inorganic sheet, film, OHP sheet, etc., and these are used as a base material and an adhesive layer on the back surface An adhesive sheet or the like provided with 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 paper in which an ink receiving layer, a film layer, and the like are not formed on normal paper. Examples of plain paper include high quality paper, medium quality paper, PPC paper, reprinted paper, recycled paper, and the like. Plain paper is a paper in which ink easily penetrates because paper fibers having a thickness of several μm to several tens of μm form voids of several tens to several hundreds of μm.

  As the coated paper, matte paper, glossy paper, semi-glossy paper or other inkjet coated paper, or so-called coated printing paper can be preferably used. Here, the coated printing paper is a printing paper conventionally used in 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 by a paint containing a binder such as starch. Coated printing paper can be applied to fine coated paper, high-quality lightweight coated paper, medium-weight lightweight coated paper, high-quality coated paper, medium-quality coated paper, art paper, cast coated paper, etc., depending on the coating amount and coating method. being classified.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Preparation of ink]
The oil-based inkjet inks of Examples 1 to 10 and Comparative Examples 1 to 5 were prepared as follows.
Each component was premixed according to the ratio shown in Tables 1 and 2, and then dispersed in a bead mill (“Dynomill KDL-A” manufactured by Shinmaru Enterprises) for about 10 minutes to prepare an ink. In Tables 1 and 2, the numbers shown for each component indicate “mass%”.
Each component shown in Tables 1 and 2 is as follows.

<Dyed lake pigment>
・ 40 First Rose Conch: “40 First Rose Conch” manufactured by Dainichi Seika Kogyo Co., Ltd., C.I. I. Pigment Red 81
・ No. 405T FANAL PINK: “No. 405T FANAL PINK” manufactured by Daido Kasei Kogyo Co., Ltd., C.I. I. Pigment Red 81: 4
<Quinacridone pigment>
FASTOGEN SUPER MAGENTA RH: “FASTOGEN SUPER MAGENTA RH” manufactured by DIC Corporation, C.I. I. Pigment Red 122,2,9-dimethylquinacridone

<Pigment dispersant>
-Solsperse 17000: "Solsperse 17000" manufactured by Nippon Lubrizol Co., Ltd., basic dispersant, non-volatile content 100%
<Solvent A>
Ethyl oleate: “EOO” manufactured by Nikko Chemicals Co., Ltd., olive fatty acid ethyl or oleate, HSP δ 7.7 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 2.2 (cal / cm ³ ) ^{1 / 2} , boiling point 355 ° C
Isopropyl palmitate: “IPP” manufactured by Nikko Chemicals Co., Ltd., isopropyl palmitate, HSP δ 7.8 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 2.2 (cal / cm ³ ) ^1/2 , boiling point 310 ° C
Ethyl isostearate: “EIS-V” manufactured by Higher Alcohol Industry Co., Ltd., ethyl isostearate, HSP δ 8.0 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 2.2 (cal / cm ³ ) ^{1 / 2} 、 Boiling point 330 ℃
Isopalmityl alcohol: “8-hexadecanol” manufactured by Alfa Aesar, HSP δ 8.9 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 4.1 (cal / cm ³ ) ^1/2 , boiling point 300 ° C
Isostearic acid: “Isostearic acid” HSPδ8.2 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 2.7 (cal / cm ³ ) ^1/2 , boiling point 350 ° C., manufactured by Tokyo Chemical Industry Co., Ltd.
<Solvent B>
Ion-exchanged water: ion-exchanged water, HSP δ 23.4 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 20.7 (cal / cm ³ ) ^1/2 , boiling point 100 ° C.
Ethanol: “Ethanol” manufactured by Wako Pure Chemical Industries, Ltd., HSP δ 12.5 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 9.0 (cal / cm ³ ) ^1/2 , boiling point 78.4 ° C.
<Solvent C>
Dodecane: “Dodecane” manufactured by Wako Pure Chemical Industries, Ltd., HSP δ 7.6 (cal / cm ³ ) ^1/2 , hydrogen bond term δh0.0 (cal / cm ³ ) ^1/2 , boiling point 216.2 ° C.
<Other solvents>
Ethylene glycol: “Ethylene glycol” manufactured by Wako Pure Chemical Industries, Ltd., HSP δ 17.8 (cal / cm ³ ) ^1/2 , hydrogen bond term δ _h 13.0 (cal / cm ³ ) ^1/2 , boiling point 197.3 ° C.

[Evaluation]
The following evaluation was performed using each of the inks described above. The results are shown in Tables 1 and 2 together.

<Saturation C ^* >
Each prepared ink is loaded into a line-type ink jet printer “OLIFIS EX9050” (manufactured by Riso Kagaku Kogyo Co., Ltd.), and a solid image is printed on plain paper “Ideal paper thin mouth” (manufactured by Riso Kagaku Kogyo Co., Ltd.). Got. Printing was performed at a resolution of 300 × 300 dpi under an ejection condition where the ink amount per dot was 42 pl. Note that the “Orifice EX 9050” is a system that uses a line-type inkjet head and conveys paper in the sub-scanning direction orthogonal to the main scanning direction (the direction in which the nozzles are arranged) to perform printing.
After leaving the obtained printed matter for 1 day, a ^* and b ^* of the printed matter are measured using a portable spectrophotometer (Spectro Eye, manufactured by X-Rite), and the following formula is used from the measured value. Saturation C ^* was determined.
C ^* = {(a ^* ) ² + (b ^* ) ² } ^1/2

The chroma C ^* thus obtained was evaluated according to the following criteria.
A: C ^* is 50 or more B: C ^* is 45 or more and less than 50 C: C ^* is less than 45

<Smear>
A printed matter was obtained in the same manner as the saturation C ^* . The obtained printed matter was allowed to stand for 1 day, and then the degree of bleeding near the boundary between the solid image portion of the printed matter and the portion where no image was formed was visually observed and evaluated according to the following criteria.
A: Level at which the boundary does not blur.
B: A level at which the boundary portion slightly blurs but does not cause a problem in actual use.
C: A level where the boundary portion is blurred and there is a problem in actual use.

<Back-through (back ΔE)>
A printed matter was obtained in the same manner as the saturation C ^* . After leaving the obtained printed matter for one day, using a portable spectrophotometer (Spectro Eye, manufactured by X-Rite), a portion where a solid image is formed on the back side of the printed matter and a portion where no solid image is formed L ^* , a ^*, and b ^* are measured, and the color difference ΔE between the portion where the solid image is formed on the back surface of the printed matter and the portion where the solid image is not formed is obtained from the measured value using the following formula: The back ΔE value was used. In the following formula, L ^{* 1} , a ^{* 1} , and b ^{* 1} are L ^* , a ^*, and b ^* of the solid image forming portion on the back surface, and L ^{* 2} , a ^{* 2} , and b ^{* 2} are on the back surface. L ^* , a ^*, and b ^* of a portion where no solid image is formed.
ΔE = {(L ^{* 1−} L ^{* 2} ) ² + (a ^{* 1−} a ^{* 2} ) ² + (b ^{* 1−} b ^{* 2} ) ² } ^1/2

The back ΔE thus obtained was evaluated according to the following criteria.
A: Back ΔE is less than 10 B: Back ΔE is 10 or more and less than 20 C: Back ΔE is 20 or more

<Storage stability>
Each prepared ink is put in an airtight container and allowed to stand for 1 week in an environment of 70 ° C. The viscosity of the ink before being left at 70 ° C. for 1 week (“initial viscosity”) and the viscosity of the ink after being left at 70 ° C. for 1 week ( “Viscosity after standing”) was measured, and the viscosity change rate of the ink was calculated by the following formula. The viscosity of the ink was measured at 23 ° C. using a rheometer AR-G2 (cone angle 2 °, diameter 40 mm) manufactured by TA Instruments Japan.
Viscosity change rate (%) = (viscosity after standing-initial viscosity) / (initial viscosity) × 100

The storage stability was evaluated according to the following criteria using the viscosity change rate calculated as described above.
A: Change rate of ink viscosity is less than 5% B: Change rate of ink viscosity is 5% or more and less than 10% C: Change rate of ink viscosity is 10% or more

The inks of Examples 1 to 10 in which the dyed lake pigment, the solvent A, and the solvent B were used were excellent in saturation (C ^* ), and bleeding and show-through were reduced.
On the other hand, Comparative Example 5 in which the quinacridone pigment was used instead of the dyed lake pigment had a lower saturation C ^* than Examples 1-10.
In Comparative Examples 1 to 4, a dyed lake pigment was used as a color material, but in Comparative Examples 1 and 4 in which the solvent B was not used, there was a level of bleeding that had a problem in actual use. In Comparative Example 2 where ethylene glycol having a high boiling point was used in place of the solvent B, bleeding that had a problem in actual use was observed. In Comparative Example 3 in which neither of the solvents A and B was used and only a solvent having a hydrogen bond term δ _h of less than 2 (cal / cm ³ ) ^1/2 was used as the solvent, ΔE was 20 or more. It was observed.

Claims (6)

An oil-based inkjet ink comprising a dyed lake pigment, a pigment dispersant, a solvent A, and a solvent B,
The solvent A has a Hansen solubility parameter δ of less than 11 (cal / cm ³ ) ^1/2 and a hydrogen bond term δ _h of 2 (cal / cm ³ ) ^1/2 or more,
The solvent B has a Hansen solubility parameter δ of 11 (cal / cm ³ ) ^1/2 or more, a hydrogen bond term δ _h of 2 (cal / cm ³ ) ^1/2 or more, and a boiling point. 150 ° C. or less,
Oil-based inkjet ink.   The oil-based inkjet ink of Claim 1 whose content of the said solvent A is 80 mass% or less of the said oil-based inkjet ink whole quantity.   The solvent A includes at least one solvent selected from the group consisting of a fatty acid ester solvent, a higher alcohol solvent having 6 or more carbon atoms, and a higher fatty acid solvent having 12 or more carbon atoms. The oil-based inkjet ink as described.   The oil-based inkjet ink of any one of Claims 1-3 in which the said solvent B contains at least 1 solvent selected from the group which consists of water, acetonitrile, and a C1-C5 alcohol.   The oil-based inkjet ink of any one of Claims 1-4 whose content of the said solvent B is 0.05 mass%-5 mass% of the said oil-based inkjet ink whole quantity. The Hansen solubility parameter δ is less than 11 (cal / cm ³ ) ^1/2 and the hydrogen bond term δ _h further comprises a solvent less than 2 (cal / cm ³ ) ^1/2 . 6. The oil-based inkjet ink according to any one of 5 above.