WO2013141246A1

WO2013141246A1 - Water-based ink set for inkjet recording

Info

Publication number: WO2013141246A1
Application number: PCT/JP2013/057850
Authority: WO
Inventors: 木村　利久; 雪彦川原田; 佐藤　義浩; 大助仲澤
Original assignee: Dic株式会社
Priority date: 2012-03-22
Filing date: 2013-03-19
Publication date: 2013-09-26
Also published as: JPWO2013141246A1; JP5500409B2

Abstract

A water-based ink set for inkjet recording using two or more types of ink, wherein a first ink contains a colorant, a resin having a hydroxy group and/or carboxyl group, and a water-soluble solvent and/or water; and a second ink contains a polyvalent metal salt of pantothenic acid, and a water-soluble solvent and/or water. The colorant is preferably a pigment, and the resin having a hydroxy group and/or carboxyl group is preferably dispersed in a water-soluble solvent and/or water.

Description

Water-based ink set for inkjet recording

The present invention relates to a water-based ink set for inkjet recording.

Printing with an inkjet printer recording device is a method that ejects ink from nozzles and adheres to the recording material. Unlike conventional printing methods, this is a printing method that does not use a plate, so on-demand printing that can accommodate a small variety of products This printing method is expected to be used in a wide range of fields. In particular, in recent years, as a recording material, many studies have been made on printing on a non-absorbing substrate such as plastic from printing on a conventional absorbing substrate such as paper.

In the case of printing using a plastic film as the recording material, since the plastic is non-absorbent, the use of water-based ink significantly reduces the drying property, resulting in non-uniform spreading of the ink when the ink is deposited. As a result, there are problems such as blurring of images such as bleeding and intercolor bleeding, and deterioration in image quality due to failure to obtain good color development. For this reason, usually, a receiving layer is provided on a plastic film (for example, refer to Patent Document 1). However, the surface of the plastic film has poor adhesion to the ink-jet ink, and a layer usually called an anchor layer, primer layer, undercoat layer, adhesive layer, etc. is formed on the film surface, and polyurethane, polyacryl, etc. The step of providing an ink receiving layer containing as a main component was essential. Such a surface treatment process not only leads to an increase in cost, but also requires a lot of time for production because the number of processes increases.

On the other hand, as an aqueous ink that does not require the receiving layer and can be printed quickly and satisfactorily even when printed on an untreated plastic film, for example, pigments, resins, alkanediol compounds or glycol ether compounds, etc. A method of using a water-based ink comprising a surfactant and / or a low surface tension organic solvent and water and having a specific surface tension and contact angle is known (see, for example, Patent Document 2).
However, since this method is substantially suitable for a polyvinyl chloride (PVC) film, for a polyethylene terephthalate (PET) film or a polypropylene (PP) film having a surface energy different from that of polyvinyl chloride, There is a possibility that the adhesion with the ink does not reach a desired level, and there is a possibility that ink bleeding of the obtained image may occur.

On the other hand, the food packaging field has the greatest demand for printing using plastic film as the recording material. In the food packaging field, a highly safe ink-jet ink has been particularly desired since a highly safe one is required.

Japanese Patent Laid-Open No. 10-119428 JP 2006-272933 A JP 2006-291176 A

An object of the present invention is to provide a two-component water-based ink set for ink-jet recording that is excellent in abrasion resistance immediately after printing and has high safety without blurring of images such as bleeding and intercolor bleeding even when printed on a plastic film. Is to provide.

The present inventors have solved the above-mentioned problems by using a pantothenic acid polyvalent metal salt and forming a water-based ink set using a resin having a hydroxy group and / or a carboxyl group as a binder resin.

Pantothenic acid polyvalent metal salt is a highly safe substance mainly used in the cosmetics and food fields. For example, calcium pantothenate is a drug (supplemented for dermatitis, lipid metabolism disorder, hypercholesterolemia, debilitating disease, pregnant women, lactating women, etc., which is prescribed when pantothenic acid is necessary) and supplements It is contained as an ingredient in health foods, beverages, food additives, feed additives, cosmetic raw materials and the like. In the present invention, as the two-component ink, a pantothenic acid polyvalent metal salt is added to one ink, and a resin having a hydroxy group and / or a carboxyl group is added to the other ink. It was found that can be solved.

In the aqueous ink jet technical field, calcium pantothenate does not cause clogging due to ink drying particularly at the tip of the discharge nozzle, always has good discharge response and discharge stability, and does not bleed on paper. It is well known that it is used as ink (see, for example, Patent Document 3). However, since the ink described in Patent Document 3 does not use a polymer resin (so-called binder resin), printing on a non-absorbable recording material such as a plastic film without a receiving layer has low ink fixability, There was a problem that a clear image could not be obtained.
On the other hand, if the binder resin is simply added, the ink itself gels due to the interaction with the pantothenic acid polyvalent metal salt, which causes poor ink ejection properties.

In the present invention, as a two-component ink, the pantothenic acid polyvalent metal salt is added to one of the inks, and the other ink has a hydroxy group capable of reacting with the pantothenic acid polyvalent metal salt and / or Since the resin having a carboxyl group is added, the ink itself is not fixed by the nozzle. On the other hand, since it is easily fixed on the plastic film as the substrate, the obtained image is free from image distortion such as bleeding and intercolor bleeding, and has excellent abrasion resistance immediately after printing.

That is, the present invention is an ink set for ink jet recording using at least two kinds of inks, and the first ink contains a color material, a resin having a hydroxy group and / or a carboxyl group, a water-soluble solvent and / or water. And the second ink provides a water-based ink set for ink-jet recording comprising a pantothenic acid polyvalent metal salt, a water-soluble solvent and / or water.

According to the present invention, there is provided an aqueous ink set for ink-jet recording which gives a printed matter which is excellent in abrasion resistance immediately after printing and has a high safety without causing image distortion such as bleeding and intercolor bleeding even when printed on a plastic film. can do.

In the water-based ink set for ink-jet recording of the present invention, the first ink is an ink containing a color material, a resin having a hydroxy group and / or a carboxyl group, a water-soluble solvent and / or water, and the second ink is a pantoten. An ink containing an acid polyvalent metal salt, a water-soluble solvent and / or water. By overprinting both inks, the ink is quickly fixed to the substrate. As a result, it is possible to obtain an ink which is free from image disturbance such as bleeding and intercolor bleeding and has excellent abrasion resistance immediately after printing.

The mechanism for the rapid fixing of both inks to the substrate by overprinting is not clear, but the following is estimated. Pantothenic acid polyvalent metal salts are triggered to grow into large aggregates by intermolecular hydrogen bonding of resins having hydroxy groups and / or carboxyl groups, and they are bundled by interactions such as van der Waals forces. There is a possibility that they are entangled in a mesh shape and interfere with each other and lose fluidity, and are fixed on the surface of the printed matter. Alternatively, a resin having a hydroxy group and / or a carboxyl group present in the first ink and a pantothenic acid polyvalent metal salt present in the second ink may react and be immobilized on the surface of the printed material. There is also sex.

(First Ink Resin having a hydroxy group and / or a carboxyl group)
The first ink used in the present invention contains a color material, a resin having a hydroxy group and / or a carboxyl group, a water-soluble solvent and / or water.

The resin having a hydroxy group and / or a carboxyl group is not particularly limited as long as a conventionally known resin having a hydroxy group and / or a carboxyl group may be used.

The resin having a hydroxy group and / or carboxyl group in the present invention may be any resin such as olefin, acrylic, vinyl chloride, vinyl acetate, and epoxy, as long as it has at least a resin having a hydroxy group and / or carboxyl group. May be. The acquisition form of the resin which has the said carboxyl group is not specifically limited. In view of ease of handling, a dispersion of a resin in a water-soluble solvent and / or water, that is, a so-called resin emulsion is preferably used rather than a solid. Commercially available resin emulsions may also be used.

Among these, a resin characterized in that resin particles of polyolefin resin, polyester resin, polyester urethane resin, acrylic resin, vinyl chloride resin, vinyl acetate resin, or epoxy resin are dispersed in a water-soluble solvent and / or water. An emulsion is preferable, and a resin emulsion in which resin particles of a polyolefin resin are dispersed in a water-soluble solvent and / or water is more preferable.

The content (% by mass) of the resin having a hydroxy group and / or a carboxyl group in the first ink is 2.0% by mass or more and 15.0% by mass or less based on the total mass of the ink. Preferably, 3.0 mass% or more and 8.0 mass% or less are still more preferable, and 3.0 mass% or more and 5.0 mass% or less are still more preferable.

The acid value of the resin having a hydroxy group and / or a carboxyl group is preferably 10 to 200 mgKOH / g per resin solid content. If the acid value is less than 10 mgKOH / g, the storage stability of the ink may be inferior. On the other hand, when the acid value exceeds 200 mgKOH / g, physical properties such as preferable durability and water resistance may not be obtained.
More preferably, it is in the range of 5 to 100 mgKOH / g, more preferably in the range of 10 to 80 mgKOH / g, and still more preferably in the range of 15 to 60 mgKOH / g.

The hydroxyl value of the resin having a hydroxy group and / or a carboxyl group is preferably 30 mgKOH / g or less per resin solid content. If the hydroxyl value exceeds 30 mgKOH / g, the storage stability of the ink may be inferior. More preferably, it is 20 mgKOH / g or less, More preferably, it is 10 mgKOH / g or less.
In addition, the acid value and hydroxyl value here are the values measured by the method based on JIS0070.

The glass transition temperature (hereinafter abbreviated as Tg) of the resin having a hydroxy group and / or a carboxyl group is preferably set as appropriate according to the desired application. For example, when printing on a plastic film having flexibility such as for packaging materials for foods, flexibility (flexibility) is required, so that Tg is preferably not so high. In order to achieve both good adhesion to an appropriate film and flexibility, the Tg of the resin having a hydroxy group and / or carboxyl group is preferably in the range of −80 ° C. to 80 ° C., and −80 ° C. to A range of 30 ° C. is particularly preferable.

The resin having a hydroxy group and / or carboxyl group has a weight average molecular weight (polystyrene conversion) of 10,000 or more and 1,000,000 or less, more preferably 20,000 or more and 700,000 or less. This is preferable because a physical property balance is easily developed.
In addition, the weight average molecular weight (Mw) here shall be calculated | required by GPC measurement on the following conditions.

[GPC measurement conditions]
Measuring device: “HLC-8220 GPC” manufactured by Tosoh Corporation
Column: Guard column “SuperHZ-L” manufactured by Tosoh Corporation (inner diameter 4.6 mm × 2 cm)
+ Tosoh Corporation “TSKgel SuperHZ4000” (inner diameter 4.6 mm × 15 cm)
+ Tosoh Corporation “TSKgel SuperHZ3000” (inner diameter 4.6 mm × 15 cm)
+ "TSKgel SuperHZ2000" manufactured by Tosoh Corporation (inner diameter 4.6 mm x 15 cm)
+ Tosoh Corporation “TSKgel SuperHZ1000” (inner diameter 4.6 mm × 15 cm)
Measurement conditions: Column temperature 40 ° C
Flow rate 0.35 ml / min Sample: A resin aqueous solution was dried and solidified, and a 0.5 mass% tetrahydrofuran (THF) solution in terms of resin solid content was filtered through a microfilter (10 μl).
Calibration curve: Monodisperse standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) A calibration curve with samples having a molecular weight of 4000000 to 250 was used.

In the case of a resin composition in which the resin having a hydroxy group and / or carboxyl group used in the present invention is dispersed in a water-soluble solvent and / or water, so-called resin emulsion, if the average particle size is too large, head clogging may occur. It causes discharge failure. Therefore, it is preferable that the average particle size of the resin particles having a hydroxy group and / or a carboxyl group is as small as possible because the influence on ejection failure is small. Specifically, it is preferably in the range of 10 nm to 500 nm, particularly preferably in the range of 10 to 300 nm.
Here, the particle diameter can be measured by a known and common centrifugal sedimentation method, laser diffraction method (light scattering method), ESA method, capillary method, electron microscope method, or the like. Preferable is measurement by Microtrac UPA using a dynamic light scattering method.

The resin emulsion that can be used in the ink of the present invention may contain an emulsifier without particular limitation within a range not impairing the effects of the present invention, depending on the desired physical properties. For example, it may be a resin emulsion obtained by a method of dropping a monomer and a polymerization initiator in the presence of an emulsifier and polymerizing, or an emulsification method by stirring an aqueous solution or suspension of a resin. Of course, resin emulsions without addition of an emulsifier may be obtained by making full use of various emulsification / dispersion techniques such as an ultrasonic irradiation technique. As emulsifiers, nonionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkyl esters, polyoxyethylene alkyl ether carboxylates, dialkyl sulfosuccinates, water-soluble acrylic resins Carboxylic acid types such as polycarboxylic acid salts, sulfonic acid types such as alkylbenzene sulfonates, anionic emulsifiers such as alcohol sulfate esters and alkylallyl sulfonates.

The polyolefin resin in the present invention has a polar group such as an amino group, a carboxyl group, and a hydroxyl group via a covalent bond to a hydrophobic polyolefin skeleton within a range that does not impair the effects of the present invention, depending on the desired physical properties, It can be set as the modified polyolefin which introduce | transduced the polymer chain.
As a method for producing a modified polyolefin, that is, a method for introducing a polar group or a polymer chain via a covalent bond to a polyolefin skeleton, a method for polymerizing a monomer having a polar group in the presence of a polyolefin, or a method for polymerizing a polymer chain into a polyolefin. Examples of the method include bonding. Depending on the properties of the target resin emulsion, the types and combinations of polyolefins, polar group-containing monomers and polymer chains can be appropriately selected. In other words, the chemical structure classification of the modified polyolefin is not particularly limited, and may be any of a random copolymer, a block copolymer, a graft modified product, and the like. As the polyolefin, any of a polyolefin having no reactive group or a polyolefin having a reactive group can be used.

As the polyolefin having no reactive group, various known polyolefins and modified polyolefins can be used, and are not particularly limited. For example, ethylene or propylene homopolymer, ethylene / propylene copolymer, ethylene or / And copolymers of propylene and other comonomers. Examples of comonomers include α-olefin comonomers having 2 or more carbon atoms such as butene-1, pentene-1, hexene-1, heptene-1, octene-1, cyclopentene, cyclohexene, and norbornene. The α-olefin comonomer is preferably an α-olefin comonomer having 2 to 8 carbon atoms, more preferably an α-olefin comonomer having 2 to 6 carbon atoms, and still more preferably an α-olefin comonomer having 2 to 4 carbon atoms. It is.

Alternatively, two or more types of copolymers of these α-olefin comonomers can be used. Also, a hydrogenated product of a copolymer of an α-olefin monomer and a comonomer such as vinyl acetate, acrylic acid ester or methacrylic acid ester, or a copolymer of two or more monomers selected from an aromatic vinyl monomer and a conjugated diene monomer , Etc. can also be used. In addition, when only calling it a copolymer, it may be a random copolymer or a block copolymer. The polyolefin may be linear or branched.

Furthermore, chlorinated polyolefins obtained by chlorinating these polyolefins can also be used. The chlorination degree of the chlorinated polyolefin is usually 5% by weight or more, preferably 10% by weight or more, and the chlorination degree is usually 50% by weight or less, preferably 30% by weight or less. However, for the purpose of reducing the environmental load, it is desirable that the polyolefin does not substantially contain chlorine. The phrase “substantially containing no chlorine” means, for example, that the chlorination rate of polyolefin is less than 5% by weight.

Examples of the polyolefin having a reactive group include a copolymer obtained by copolymerizing an unsaturated compound having no reactive group and an unsaturated compound having a reactive group at the time of polyolefin polymerization, or radical polymerization having a reactive group. A polymer obtained by graft-polymerizing a polymerizable unsaturated compound onto a polyolefin, or a polymer obtained by converting a polyolefin having an unsaturated end group into an element group of group 13 to group 17 can be used.

Examples of the reactive group include a carboxylic acid group, a dicarboxylic acid anhydride group, and a dicarboxylic acid anhydride monoester group, a hydroxyl group, an amino group, an epoxy group, an isocyanate group, and the like, and a carboxylic acid group and a dicarboxylic acid anhydride group. And a dicarboxylic anhydride monoester group is more preferred. Carboxylic acid groups, dicarboxylic acid anhydride groups, and dicarboxylic acid anhydride monoester groups are not only highly reactive and easy to bond with hydrophilic polymers, but also contain many unsaturated compounds having these groups and are common to polyolefins. This is because polymerization or graft reaction is also easy, and so-called acid-modified polyolefin resins in which polyolefin has these groups are excellent in water dispersibility.

A copolymer obtained by copolymerizing an unsaturated compound having no reactive group at the time of polyolefin polymerization and an unsaturated compound having a reactive group is a copolymer in which an unsaturated compound having a reactive group is inserted into the main chain. It is. For example, α-olefin such as ethylene, propylene, butene, (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, (meth) acrylic acid (dimethylamino) ) Ethyl, (meth) acrylic acid (2-isocyanato) ethyl, and α, β-unsaturated carboxylic acid such as maleic anhydride, the same ester or anhydride. (In the present invention, “(meth) acrylic acid” means “acrylic acid or methacrylic acid”).)
Specific examples of these copolymers include propylene-butene-maleic anhydride copolymers. These may be used individually by 1 type and may be used in combination of 2 or more type. Of course, it is also possible to use a commercially available product.

A polymer obtained by graft-polymerizing a radically polymerizable unsaturated compound having a reactive group to a polyolefin is obtained by graft-polymerizing a radically polymerizable unsaturated compound having a reactive group to a previously polymerized polyolefin. The unsaturated compound it has is grafted to the main chain. For example, (meth) acrylic acid, fumaric acid, maleic acid or its anhydride, itaconic acid or its anhydride, crotonic acid, 2-hydroxyethyl (meth) acrylate or (meth) acrylic acid, such as polyethylene and polypropylene A polymer grafted with 2-hydroxypropyl, (meth) acrylamide, (dimethylamino) ethyl (meth) acrylate, glycidyl (meth) acrylate, (2-isocyanato) ethyl (meth) acrylate, or the like. These may be used individually by 1 type and may be used in combination of 2 or more type. As polyolefin of this reaction, the polyolefin which does not have the above-mentioned reactive group can be used.

Specific examples of the polymer obtained by graft polymerization of a radically polymerizable unsaturated compound having a reactive group to a polyolefin include, for example, maleic anhydride-modified polypropylene and chlorinated products thereof, maleic anhydride-modified propylene-ethylene copolymer and chlorine thereof. , A maleic anhydride modified propylene-butene copolymer and its chlorinated product, an acrylic acid modified polypropylene and its chlorinated product, an acrylic acid modified propylene-ethylene copolymer and its chlorinated product, an acrylic acid modified propylene-butene copolymer and Examples thereof include chlorinated substances. These may be used individually by 1 type and may be used in combination of 2 or more type.

The radical polymerization initiator used in the graft polymerization can be appropriately selected from ordinary radical initiators, such as organic peroxides such as benzoyl peroxide and t-butylperoxyisopropyl monocarbonate, azonitrile, etc. Can be mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.

The method for producing a polymer obtained by graft polymerization of a radically polymerizable unsaturated compound having a reactive group onto a polyolefin is not particularly limited, and any production method may be used. For example, solution modification method (method of reacting by heating and stirring in a solution), melt modification method (method of reacting by melting and heating and stirring without a solvent, or method of reacting by heating and kneading with an extruder), etc. It is done.

A polymer obtained by converting a polyolefin having an unsaturated end group into an element group of group 13 to group 17 is, for example, a double bond of a polyolefin having a terminal double bond as described in JP-A-2001-288372. A polyolefin having part thereof converted into a group 13 element group such as a boron group or an aluminum group, and a double bond part of a polyolefin having a terminal double bond as described in JP-A-2005-48172 is converted into a halogen element. Polyolefin, a polyolefin obtained by converting a double bond portion of a propylene-based polymer having a terminal double bond into a mercapto group as described in JP-A-2001-98140 can be used. Usually, a block copolymer is used as a block copolymer. Obtainable.

The polymer chain introduced into the hydrophobic polyolefin skeleton via a covalent bond can be used without particular limitation as long as the effects of the present invention are not impaired, depending on the desired physical properties. It may be linear or branched. For example, synthetic polymer such as poly (meth) acrylic resin, polyester resin, polyether resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, semi-synthetic polymer such as cationic starch, dextrin, hydroxyethyl cellulose, agar, gum arabic, gelatin, etc. Any of these natural polymers can be used. The polymer chain may have a reactive group.

However, poly (meth) acrylic resins, polyester resins, polyether resins, polyvinyl alcohol resins, and polyvinylpyrrolidone resins are more preferable, and amphiphilic polyether resins are even more preferable. These may be used individually by 1 type and may be used in combination of 2 or more type.

The poly (meth) acrylic resin used for the polymer chain is obtained by polymerizing an unsaturated carboxylic acid or an ester or anhydride thereof by radical polymerization, anionic polymerization, or cationic polymerization. Examples of the unsaturated carboxylic acid or its ester or anhydride include (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, (meth) acrylic acid (dimethyl) Amino) ethyl, (meth) acrylic acid (2-isocyanato) ethyl, maleic anhydride and the like. In addition, depending on the desired physical properties, a hydrophobic radical polymerizable compound (hydrophobic monomer) is used in order to provide good adhesion to various thermoplastic resin film substrates within a range that does not impair the effects of the present invention. Can be copolymerized. Examples of the copolymerizable hydrophobic monomer include a (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms, an aryl group or an arylalkyl group, and a hydrocarbon group having 1 to 12 carbon atoms. Examples thereof include polymerizable vinyl monomers.

The polyvinyl alcohol resin used for the polymer chain can be usually obtained by polymerizing vinyl acetate to obtain polyvinyl acetate and then saponifying. The saponification degree may be complete saponification or partial saponification. The polyvinyl pyrrolidone resin used for the polymer chain can be obtained by polymerizing vinyl pyrrolidone. Of course, a commercially available product may be used.

The method for introducing the polymer chain into the polyolefin is not particularly limited. For example, a method of radical polymerization in the presence of a polyolefin, an acrylic system having a reactive group such as a hydroxyl group, an amino group, a glycidyl group, or an (anhydrous) carboxylic acid group. Examples thereof include a method of reacting a resin with a polyolefin having a reactive group.

A polyether resin having amphiphilic properties used as a polymer chain introduced into a hydrophobic polyolefin skeleton via a covalent bond can be obtained by ring-opening polymerization of cyclic alkylene oxide or cyclic alkylene imine. The method for bonding with polyolefin is not particularly limited. For example, a method of ring-opening polymerization of cyclic alkylene oxide in a polyolefin having a reactive group, a reaction of polyether polyol or polyether amine obtained by ring-opening polymerization, etc. Examples thereof include a method of reacting a polyether resin having a reactive group with a polyolefin having a reactive group.

Polyetheramine is a compound having a primary amino group as a reactive group at one or both ends of a resin having a polyether skeleton. As the polyetheramine, Jeffamine M series, D series, ED series, etc. manufactured by Huntsman, USA may be used.
Polyether polyol is a compound having hydroxyl groups as reactive groups at both ends of a resin having a polyether skeleton. Preferred examples of the polyalkylene oxide and polyalkyleneimine exhibiting hydrophilicity include polyethylene oxide, polypropylene oxide, and polyethyleneimine.

One or more reactive groups may be used, but it is more preferable to have only one reactive group. This is because when there are two or more reactive groups, there is a possibility that a three-dimensional network structure will be formed upon bonding with the polyolefin, resulting in gelation. However, even if it has a plurality of reactive groups, the gelation described above can be avoided if there is only one reactive group having a higher reactivity than others. For example, a hydrophilic polymer having a plurality of hydroxyl groups and one amino group having a higher reactivity is one preferred example. The reactivity here is the reactivity with the reactive group which polyolefin has.
As the polyolefin resin in the present invention, an olefin resin marketed as an aqueous dispersion can be preferably used. For example, the Hardren series manufactured by Toyobo Co., Ltd., the Aptolock series manufactured by Mitsubishi Chemical Corporation, the Allobase series manufactured by Unitika Ltd., etc. can be used.

(First ink coloring material)
The color material used in the present invention is not particularly limited, and color materials usually used in water-based inkjet inks can be used, and examples thereof include pigments and dyes.
If the application requires weather resistance and water resistance, it is preferable to use a pigment. As the pigment, known and commonly used organic pigments or inorganic pigments can be used.

The pigment used in the present invention is at least one pigment selected from known and commonly used organic pigments or inorganic pigments. In addition, the present invention can be applied to either an untreated pigment or a treated pigment.
In the case of printing using plastic as a recording material, as ink-jet ink, in addition to yellow ink, cyan ink, magenta ink, black ink, etc., white ink is also used for the purpose of improving visibility. These pigments used are not particularly limited, and those usually used as pigments for water-based inkjet recording inks can be used. Specifically, it can be dispersed in water or a water-soluble organic solvent, and a known inorganic pigment or organic pigment can be used. Examples of the inorganic pigment include carbon black produced by a known method such as iron oxide, a contact method, a furnace method, and a thermal method. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines). Pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelates, acidic dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

For example, as a pigment used for black ink, carbon black, No. manufactured by Mitsubishi Chemical Corporation. 2300, no. 2200B, no. 900, no. 960, No. 980, no. 33, no. 40, No, 45, No. 45L, no. 52, HCF88, MA7, MA8, MA100, etc. are Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. made by Columbia, and Regal 400R, Regal 330R, Regal 660R, Mull 660R, Mogul made by Cabot. Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. are Color Black FW1, FW2, FW2V, FW18, FW200, FW200, S170, S150, S35, S150, S35, S160, U , V, 1400U, Special lack 6, the 5, 4, 4A, NIPEX150, NIPEX160, NIPEX170, NIPEX180 and the like.

Also, specific examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 174, 180, 185 and the like.

Also, specific examples of pigments used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 146, 168, 176, 184, 185, 202, 209, etc. It is done.

Also, specific examples of pigments used for cyan ink include C.I. I. Pigment blue 1, 2, 3, 15, 15: 3, 15: 4, 16, 22, 60, 63, 66, and the like.

Specific examples of pigments used in white inks include silicas such as alkaline earth metal sulfates, carbonates, finely divided silicic acids, synthetic silicates, calcium silicates, alumina, alumina hydrates, Examples thereof include titanium oxide, zinc oxide, talc, and clay. The inorganic white pigment may be surface-treated by various surface treatment methods.

Also, examples of the dye include C.I. I. Acid Black 1, 2, 7, 16, 17, 24, 26, 28, 31, 41, 48, 52, 58, 60, 63, 94, 107, 109, 112, 118, 119, 121, 122, 131, 155, 156; C.I. I. Acid Yellow 1, 3, 4, 7, 11, 12, 13, 14, 17, 18, 19, 23, 25, 29, 34, 38, 40, 41, 42, 44, 49, 53, 55, 59, 61, 71, 72, 76, 78, 79, 99, 111, 114, 116, 122, 135, 142, 161, 172; I. Acid Orange 7, 8, 10, 19, 20, 24, 28, 33, 41, 45, 51, 56, 64; C.I. I. Acid Red 1, 4, 6, 8, 13, 14, 15, 18, 19, 21, 26, 27, 30, 32, 34, 35, 37, 40, 42, 44, 51, 52, 54, 57, 80, 82, 83, 85, 87, 88, 89, 92, 94, 97, 106, 108, 110, 111, 114, 115, 119, 129, 131, 133, 134, 135, 143, 143: 1, 144, 152, 154, 155, 172, 176, 180, 184, 186, 187, 249, 254, 256, 289, 317, 318; I. Acid Violet 7, 11, 15, 34, 35, 41, 43, 49, 51, 75; I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 27, 29, 40, 41, 43, 45, 49, 51, 53, 55, 56, 59, 62, 78, 80, 81, 83, 90, 92, 93, 102, 104, 111, 113, 117, 120, 124, 126, 138, 145, 167, 171, 175, 183, 229, 234, 236, 249; I. Acid Green 3, 9, 12, 16, 19, 20, 25, 27, 41, 44; C.I. I. Acid dyes such as brown 4 and 14,

C. I. Basic Black 2.8; C.I. I. Basic Yellow 1, 2, 11, 12, 14, 21, 32, 36; I. Basic Orange 2, 15, 21, 22; I. Basic Red 1, 2, 9, 12, 13, 37; I. Basic Violet 1, 3, 7, 10, 14; I. Basic Blue 1, 3, 5, 7, 9, 24, 25, 26, 28, 29; I. Basic green 1, 4; basic brown 1, 12, etc. basic dyes,

C. I. Direct Black 2, 4, 9, 11, 14, 17, 19, 22, 27, 32, 36, 38, 41, 48, 49, 51, 56, 62, 71, 74, 75, 77, 78, 80, 105, 106, 107, 108, 112, 113, 117, 132, 146, 154, 168, 171, 194; C. Direct Yellow 1, 2, 4, 8, 11, 12, 24, 26, 27, 28, 33, 34, 39, 41, 42, 44, 50, 51, 58, 72, 85, 86, 87, 88, 98, 100, 110, 127, 135, 141, 142, 144; C.I. I. Direct Orange 6, 8, 10, 26, 29, 41, 49, 52, 102; C.I. I. Direct Red 1, 2, 4, 8, 9, 11, 13, 15, 17, 20, 23, 24, 28, 31, 33, 37, 39, 44, 46, 47, 48, 51, 59, 62, 63, 73, 75, 77, 80, 81, 83, 84, 85, 87, 89, 90, 94, 95, 99, 101, 108, 110, 145, 189, 197, 220, 224, 225, 226, 227, 230, 250, 254, 256, 257; I. Direct violet 1, 7, 9, 12, 35, 48, 51, 90, 94; I. Direct Blue 1, 2, 6, 8, 15, 22, 25, 34, 69, 70, 71, 72, 75, 76, 78, 80, 81, 82, 83, 86, 90, 98, 106, 110, 110, 120, 123, 158, 163, 165, 192, 193, 194, 195, 196, 199, 200, 201, 202, 203, 207, 218, 236, 237, 239, 246, 258, 287; Direct Green 1, 6, 8, 28, 33, 37, 63, 64; C.I. I. Direct dyes such as Brown 1A, 2, 6, 25, 27, 44, 58, 95, 10, 101, 106, 112, 173, 194, 195, 209, 210, 211,

C. I. Reactive black 1, 3, 5, 6, 8, 12, 14; I. Reactive yellow 1, 2, 3, 13, 14, 15, 17; I. Reactive Orange 2, 5, 7, 16, 20, 24; Reactive Red 6, 7, 11, 12, 15, 17, 21, 23, 24, 35, 36, 42, 63, 66, 84, 184; C . I. Reactiv Violet 2, 4, 5, 8, 9; I. Reactive Blue 2, 5, 7, 12, 13, 14, 15, 17, 18, 19, 20, 21, 25, 27, 28, 37, 38, 40, 41; C.I. I. Reactive dyes such as Reacteb Green 5, 7; Reacteb Brown 1, 7, 16, etc.

C. I. Food Black 1, 2; C.I. I. Food Yellow 3, 4, 5; C.I. I. Food Red 2, 3, 7, 9, 14, 52, 87, 92, 94, 102, 104, 105, 106; C.I. I. Food Violet 2; C.I. I. Food Blue 1, 2; C.I. I. Examples include food dyes such as Food Green 2 and 3.

In the present invention, a so-called self-dispersing pigment (surface-treated pigment) having a water dispersibility-imparting group on the pigment surface and capable of stably maintaining the dispersion state without a dispersant may be used. So-called capsule pigments (water-dispersible polymer-containing pigments) that can be stably maintained without a dispersant, or pigments dispersed with a dispersant may be used.
The average particle size of the pigment is preferably the particle size normally used for inkjet inks, specifically 50 to 500 nm is preferable, and 50 to 300 nm is more preferable for color inks.

The pigment may be dispersed in water using a known and commonly used pigment dispersant or binder, or a surfactant may be used.
The pigment dispersant is preferably an aqueous resin, and preferable examples include acrylic resins such as polyvinyl alcohols, polyvinyl pyrrolidones, acrylic acid-acrylic acid ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid. Styrene-acrylic such as copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer Examples thereof include resins, styrene-maleic acid copolymers, styrene-maleic anhydride copolymers, vinylnaphthalene-acrylic acid copolymers, and salts of the aqueous resins.
The compounds for forming the copolymer salt include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, and diethylamine, ammonia, ethylamine, triethylamine, propylamine, isopropylamine, Examples include propylamine, butylamine, isobutylamine, triethanolamine, diethanolamine, aminomethylpropanol, and morpholine. The amount of the compound used to form these salts is preferably equal to or greater than the neutralization equivalent of the copolymer.
Of course, it is also possible to use a commercial item. Commercially available products include Ajinomoto Fine Techno Co., Ltd. product Ajisper PB series, Big Chemie Japan Co., Ltd. Disperbyk series, BYK-series, EFKA series manufactured by Ciba Specialty Chemicals.

(First ink, water-soluble solvent and / or water)
The water-soluble solvent and / or water used in the present invention may be water alone or a mixed solvent composed of water and a water-soluble solvent. Examples of the water-soluble solvent include ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and methyl isobutyl ketone; methanol, ethanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, 2-methoxyethanol, Alcohols such as tetrahydrofuran; ethers such as 1,4-dioxane and 1,2-dimethoxyethane; amides such as dimethylformamide and N-methylpyrrolidone, and particularly ketones having 3 to 6 carbon atoms And a compound selected from the group consisting of alcohols having 1 to 5 carbon atoms.

(First ink production method)
The first ink used in the present invention is to prepare a dispersion (pigment paste) of the pigment, dilute it with water, add the resin having the hydroxy group and / or carboxyl group, and wet as necessary. An ink can be prepared by adding an agent (drying inhibitor), a penetrating agent, or other additives.

(Pigment paste)
As a method for preparing the pigment paste, the following method can be employed.
(1) A method of preparing a pigment paste by adding a pigment to an aqueous medium containing a pigment dispersant and water and then dispersing the pigment in the aqueous medium using a stirring / dispersing device.
(2) The pigment and the pigment dispersant are kneaded using a kneader such as two rolls or a mixer, and the resulting kneaded product is added to an aqueous medium containing water, and the pigment is then mixed using a stirring / dispersing device. A method of preparing a paste.
(3) After adding a pigment to a solution obtained by dissolving a pigment dispersant in an organic solvent compatible with water such as methyl ethyl ketone and tetrahydrofuran, the pigment is added to the organic solution using a stirring / dispersing device. And then phase-emulsifying using an aqueous medium, and then the organic solvent is distilled off to prepare a pigment paste.

The kneader is not particularly limited, and examples thereof include a Henschel mixer, a pressure kneader, a Banbury mixer, and a planetary mixer. Also, the stirring / dispersing device is not particularly limited, and examples thereof include an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roll mill, a sand mill, a sand grinder, a dyno mill, a disperse mat, an SC mill, and a nanomizer.
One of these may be used alone, or two or more devices may be used in combination.

The amount of pigment in the pigment paste is preferably 5 to 60% by mass, more preferably 10 to 50% by mass. When the pigment amount is less than 5% by mass, the water-based ink prepared from the pigment paste is insufficiently colored, and a sufficient image density tends not to be obtained. On the other hand, when the amount is more than 60% by mass, the dispersion stability of the pigment tends to decrease in the pigment paste.

In addition, in the ink preparation example, coarse particles cause nozzle clogging and other image characteristics, and therefore it is preferable to remove the coarse particles by centrifugation or filtration after ink preparation. .

(Wetting agent)
The wetting agent is added for the purpose of preventing the ink from drying. The content of the wetting agent in the ink for the purpose of preventing drying is preferably 3 to 50% by mass.
The wetting agent used in the present invention is not particularly limited, but a wetting agent that is miscible with water and can prevent clogging of the head of an inkjet printer is preferable. For example, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol having a molecular weight of 2000 or less, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butane Examples include diol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, mesoerythritol, pentaerythritol, and the like. Among them, the inclusion of propylene glycol and 1,3-butanediol has safety and excellent effects in ink drying properties and ejection performance.

(Penetration agent)
The penetrant is added for the purpose of improving the permeability to a recording medium and adjusting the dot diameter on the recording medium. Examples of the penetrant include lower alcohols such as ethanol and isopropyl alcohol, ethylene oxide adducts of alkyl alcohols such as ethylene glycol hexyl ether and diethylene glycol butyl ether, and propylene oxide adducts of alkyl alcohols such as propylene glycol propyl ether.
The content of the penetrant in the ink is preferably 0.01 to 10% by mass.

(Surfactant)
The surfactant is added to adjust ink properties such as surface tension. The surfactant that can be added for this purpose is not particularly limited, and examples include various anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Of these, anionic surfactants and nonionic surfactants are preferred.

Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonate of higher fatty acid ester, higher alcohol ether. Sulfate salts and sulfonates of the above, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, etc. Specific examples include dodecylbenzene sulfonate, isopropyl naphthalene sulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenyl sulfonate, dibutylphenylphenol disulfate. Such as phosphate salt can be mentioned.

Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester , Polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, fatty acid alkylolamide, alkyl alkanolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, Polyethylene glycol polypropylene glycol block copolymer, etc. Among these, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, Fatty acid alkylolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymer are preferred.

Other surfactants include silicone surfactants such as polysiloxane oxyethylene adducts; fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers. Biosurfactants such as spicrispolic acid, rhamnolipid, lysolecithin and the like can also be used.

These surfactants can be used alone or in combination of two or more. In consideration of the dissolution stability of the surfactant, the HLB is preferably in the range of 7-20. When a surfactant is added, the addition amount is preferably in the range of 0.001 to 2% by mass, more preferably 0.001 to 1.5% by mass, based on the total mass of the ink. More preferably, the content is in the range of 01 to 1% by mass. When the addition amount of the surfactant is less than 0.001% by mass, the effect of adding the surfactant tends to be not obtained, and when it exceeds 2% by mass, problems such as blurring of the image are likely to occur. .

Moreover, preservatives, viscosity modifiers, pH adjusters, chelating agents, plasticizers, antioxidants, ultraviolet absorbers and the like can be added as necessary.

The amount of pigment in the inkjet recording ink prepared from the pigment paste is 1 to 20% by mass in order to obtain a sufficient image density and to ensure dispersion stability of the pigment in the ink. preferable.

In the present invention, the surface tension of the first ink is preferably 20 mN / m or more and 60 mN / m or less. More preferably, it is 20 mN / m or more and 45 mN / m or less, More preferably, it is 20 mN / m or more and 40 mN / m or less. If the surface tension is less than 20 mN / m, the liquid may overflow on the nozzle surface and printing may not be performed normally. On the other hand, when it exceeds 60 mN / m, there is a tendency that the non-absorbing base material is easily repelled.

In the present invention, the viscosity of the first ink is preferably 1.2 mPa · s or more and 20.0 mPa · s or less, more preferably 2.0 mPa · s or more and less than 15.0 mPa · s, and still more preferably. 3.0 mPa · s or more and less than 12.0 mPa · s. When the viscosity is within this range, it is possible to achieve excellent dischargeability and good jetability over a long period of time.
The surface tension and viscosity of the first ink can be maintained in the above preferred ranges by adjusting the type and amount of surfactant and water-soluble solvent to be contained.

(Second ink pantothenic acid polyvalent metal salt)
The second ink used in the present invention contains a pantothenic acid polyvalent metal salt, a water-soluble solvent and / or water.
The pantothenic acid polyvalent metal salt used in the present invention is a salt of pantothenic acid which is a kind of water-soluble vitamin B group which exists widely in nature, and consists of alkaline earth metals such as magnesium and calcium, zinc, barium and the like. Multivalent metal salts can be preferably used.
The content of the pantothenic acid polyvalent metal salt is 0.5 to 10% by mass, more preferably 0.8 to 5% by mass, and still more preferably 1 to 3% by mass with respect to the total amount of the second ink. It is preferable to prepare as follows. If the pantothenic acid polyvalent metal salt content is too small, the gelation effect may not be sufficiently obtained. On the other hand, if the pantothenic acid polyvalent metal salt content is too large, image sharpness may deteriorate due to precipitation of excess pantothenic acid polyvalent metal salt. There is.

The second ink used in the present invention may be prepared by appropriately adding a coloring material used in the first ink, a wetting agent (drying inhibitor), a penetrating agent, or other additives. it can.
The surface tension of the second ink is preferably 20 mN / m or more and 60 mN / m or less. More preferably, it is 20 mN / m or more and 45 mN / m or less, More preferably, it is 20 mN / m or more and 40 mN / m or less. If the surface tension is less than 20 mN / m, the liquid may overflow on the nozzle surface and printing may not be performed normally. On the other hand, when it exceeds 60 mN / m, the permeability to the recording medium is lowered and the repelling occurs, so that the image reproducibility tends to be inferior.

The viscosity of the second ink is preferably 1.2 mPa · s or more and 20.0 mPa · s or less, more preferably 2.0 mPa · s or more and less than 15.0 mPa · s, and further preferably 3.0 mPa · s. s or more and less than 12.0 mPa · s. When the viscosity is within this range, it is possible to achieve excellent dischargeability and good jetability over a long period of time.
The surface tension and viscosity of the second ink can be maintained in the above preferred ranges by adjusting the type and amount of the surfactant and water-soluble solvent to be contained.

(Ink set)
The water-based ink set for ink-jet recording of the present invention includes at least the first ink and the second ink, and the first ink and the second ink are non-absorbing so that they are in contact with each other. An image is formed on the substrate.

(Non-absorbing substrate)
As a plastic film which is a non-absorbing substrate used in the present invention, for example, those used for food packaging materials can be used, and known plastic films can be used. Specific examples include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyolefin films such as polyethylene and polypropylene, polyamide films such as nylon, polystyrene films, polyvinyl alcohol films, polyvinyl chloride films, polycarbonate films, polyacrylonitrile films, poly Examples include biodegradable films such as lactic acid films. Polyester film, polyolefin film, and polyamide film are particularly preferable, and polyethylene terephthalate, polypropylene, and nylon are more preferable. Moreover, the above-mentioned film coated with polyvinylidene chloride or the like for imparting a barrier property may be used, and if necessary, a film in which a deposited layer of a metal oxide such as aluminum or a metal oxide such as silica or alumina is used in combination. May be.

The plastic film may be an unstretched film, but is preferably stretched uniaxially or biaxially. Further, the surface of the film may be untreated, but those subjected to various treatments for improving adhesive properties such as corona discharge treatment, ozone treatment, low temperature plasma treatment, flame treatment, glow discharge treatment and the like are preferable.
The film thickness of the plastic film is appropriately changed according to the application. For example, in the case of a flexible packaging application, the film thickness is 10 μm to 100 μm assuming that it has flexibility, durability, and curl resistance. Preferably there is. More preferably, it is 10 μm to 30 μm.

The water-based ink set for ink-jet recording according to the present invention includes not only a normal ink-jet recording apparatus but also a recording apparatus equipped with a heater for controlling ink drying or the like, or an intermediate transfer mechanism, and a recording material as an intermediate. It can also be used in a recording apparatus or the like that prints on a recording medium such as a non-absorbing substrate after printing.
Any conventionally known method can be used as the ink jet recording method. For example, a method of ejecting droplets using vibration of a piezoelectric element (a recording method using an ink jet head that forms ink droplets by mechanical deformation of an electrostrictive element) or a method of using thermal energy can be given.

In the method of the present invention, when the first ink and the second ink are applied on the non-absorbing substrate so as to be in contact with each other, there is no particular limitation on the order of the application, and the application of the first ink The second ink may be applied later, the first ink may be applied after the second ink application, or may be applied simultaneously.

The application amounts of the first ink and the second ink applied to form one pixel are not necessarily equal, but are within a range of 1:10 to 10: 1 by mass ratio. Thus, it is a preferable aspect to apply ink.

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples. In addition, the part in an Example below represents a mass part.

(Preparation examples Cyan ink preparation Tables 1 and 5)
Stir 20 parts of cyan pigment “FANTOGEN BLUE FSJ-SD” manufactured by DIC Corporation, 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd. as a pigment dispersant, 5 parts of isopropyl alcohol, and 45 parts of pure water. Mixed. Next, after the kneaded meat was dispersed using a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a cyan pigment dispersion prepared to have a pigment concentration of 15% by mass. 27 parts of the cyan pigment dispersion, 3 parts of resin part (solid content), 15 parts of propylene glycol, 10 parts of 1.3-butanediol, 0.5 part of Surfinol 440, and the remaining amount of pure water were mixed. The liquid was filtered through a 0.5 μm filter to obtain cyan inks (C-1) to (C-6) and (HC-7).

(Preparation example Yellow ink Table 2)
20 parts of a yellow pigment “NOVOPERM YELLOW 4G-01” manufactured by Clariant Japan Co., Ltd., 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd. as a pigment dispersant, 5 parts of isopropyl alcohol, and 45 parts of pure water Stir and mix. Next, after the kneaded meat was dispersed using a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a yellow pigment dispersion prepared to have a pigment concentration of 15% by mass.
33 parts of the yellow pigment dispersion, 3 parts of resin part (solid content), 15 parts of propylene glycol, 10 parts of 1.3-butanediol, 0.5 part of Surfinol 440 and the remaining amount of pure water were mixed. The liquid was filtered through a 0.5 μm filter to obtain yellow inks (Y-1) to (Y-6).

(Preparation examples Magenta ink Table 3)
20 parts of magenta pigment “Irgazin Magenta 2012” manufactured by BASF Corporation, 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd. as a pigment dispersant, 5 parts of isopropyl alcohol, and 45 parts of pure water were mixed. . Next, after the kneaded meat was dispersed using a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a magenta pigment dispersion prepared to have a pigment concentration of 15% by mass.
47 parts of the magenta pigment dispersion, 3 parts of resin (solid content), 15 parts of propylene glycol, 10 parts of 1.3-butanediol, 0.5 part of Surfinol 440, and pure water (remaining amount) are mixed. The mixed solution was filtered through a 0.5 μm filter to obtain magenta inks (M-1) to (M-6) and (HM-7).

(Preparation example Black ink Table 4)
20 parts of black pigment “Carbon Black # 960” manufactured by Mitsubishi Chemical Corporation, 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd., 5 parts of isopropyl alcohol, and 45 parts of pure water as a pigment dispersant Mixed. Next, after kneading with a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a black pigment dispersion prepared to have a pigment concentration of 15% by mass.
30 parts of the black pigment dispersion, 3 parts of resin part (solid content), 15 parts of propylene glycol, 10 parts of 1.3-butanediol, 0.5 part of Surfinol 440 and pure water (remaining amount) are mixed. The mixed solution was filtered through a 0.5 μm filter to obtain black inks (K-1) to ((K-6) and (HK-7).

Details of the substances described in Tables 1 to 5 are as follows. Unless otherwise indicated, the reagents were used as they were.
Hardren NA-3002 (trade name): Olefin emulsion (acid-modified polyolefin resin, manufactured by Toyobo Co., Ltd., pH: 8, acid value: 33 mgKOH / g, solid content 30%)
Aptolock BW-5550 (trade name): olefin emulsion (acid-modified polyolefin resin having a polyether polymer chain, manufactured by Mitsubishi Chemical Corporation, pH: 8, acid value: 18 mgKOH / g, solid content 30%)
Vylonal MD-2000: polyester emulsion (polyester resin, manufactured by Toyobo Co., Ltd., pH: 6, solid content 40%)
Hydran AP-40F (trade name): polyester urethane emulsion (polyester urethane resin, manufactured by DIC Corporation, pH: 7, acid value: 25 mg KOH / g, solid content 22%)
Boncoat WKA-565 (trade name): Acrylic aqueous emulsion (urethane acrylic resin, manufactured by DIC Corporation, pH: 9, acid value: 16 mgKOH / g, solid content 36%)
Jonkrill 780 (trade name): Acrylic aqueous emulsion (acrylic resin, manufactured by BASF Corp., pH: 8, acid value: 46 mg KOH / g, solid content 48%)
Hydran CP-7060 (trade name): Polycarbonate urethane emulsion (urethane resin, manufactured by DIC Corporation, pH: 3, solid content 21%)
Surfynol 440 (trade name): Surfactant D-calcium pantothenate manufactured by Air Products Japan Co., Ltd .: Daiichi Fine Chemical Co., Ltd.

*** Cannot be measured or below the lower limit of quantification

(Measurement method of acid value)
The acid value was measured by a method based on JIS K0070. In the present invention, the following solvents were used as measurement solvents.
10 g of the resin obtained by drying and solidifying the resin aqueous solution is weighed into a 300 ml Erlenmeyer flask, and about 50 ml of a mixed solvent of ethanol: benzene = 1: 2 is added to dissolve the resin. Subsequently, using a phenolphthalein indicator, titration was performed with a 0.1 mol / L potassium hydroxide ethanol solution that had been standardized in advance, and the acid value ( mgKOH / g) is determined.

In the formula, A is the acid value of the resin (mgKOH / g), B is the amount of 0.1 mol / L potassium hydroxide ethanol solution used for titration (ml), and f is the 0.1 mol / liter potassium hydroxide ethanol solution. The factor, S is the mass (g) of the resin, and 5.611 is a value (56.11 / 10) of 1/10 of the formula weight of potassium hydroxide. *

For resins that do not dissolve in about 50 ml of a mixed solvent of ethanol: benzene = 1: 2, select either 50 ml of ethanol or about 50 ml of a mixed solvent of ethanol / pure water = 1: 1. The others are titrated by the same operation. *

(Measurement method of hydroxyl value)
The hydroxyl value was measured by a method based on JIS K0070. In this invention, the solvent shown below was used as a solvent for a measurement.
3 g of resin obtained by drying and solidifying the above resin aqueous solution is weighed into a 100 ml Erlenmeyer flask, 10.0 ml of acetic anhydride solution is added and stirred for 15 minutes. Add 2 ml of water and 10.0 ml of pyridine + water (3 + 1) and stir for 5 minutes. 10.0 ml of pyridine was added, titration was performed with a 0.5 mol / l potassium hydroxide aqueous ethanol solution, and the hydroxyl value (mgKOH / g) was determined according to the calculation formula (2).

In the formula, A is the hydroxyl value of the resin (mgKOH / g), B is a blank value, C is the amount of 0.5 mol / l potassium hydroxide ethanol aqueous solution used for titration (ml), f is the factor of the titrant, D Is a concentration conversion factor, E is a unit conversion factor, and S is a sampled amount.

(Measurement method of Tg (glass transition temperature))
The DSC measurement was performed at a heating rate of 5 ° C./min according to JIS7122 using a thermal analyzer DSC10 manufactured by DuPont.

(Measurement method of weight average molecular weight (Mw))
Mw was determined by GPC measurement under the following conditions.
[GPC measurement conditions]
Measuring device: “HLC-8220 GPC” manufactured by Tosoh Corporation
Column: Guard column “SuperHZ-L” manufactured by Tosoh Corporation (inner diameter 4.6 mm × 2 cm)
+ Tosoh Corporation “TSKgel SuperHZ4000” (inner diameter 4.6 mm × 15 cm)
+ Tosoh Corporation “TSKgel SuperHZ3000” (inner diameter 4.6 mm × 15 cm)
+ "TSKgel SuperHZ2000" manufactured by Tosoh Corporation (inner diameter 4.6 mm x 15 cm)
+ Tosoh Corporation “TSKgel SuperHZ1000” (inner diameter 4.6 mm × 15 cm)
Measurement conditions: Column temperature 40 ° C
Flow rate 0.35 ml / min Sample: A resin aqueous solution was dried and solidified, and a 0.5 mass% tetrahydrofuran (THF) solution in terms of resin solid content was filtered through a microfilter (10 μl).
Calibration curve: Monodisperse standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) A calibration curve with samples having a molecular weight of 4000000 to 250 was used.

(Examples 1 to 98, Comparative Examples 1 to 6)
Each ink set was loaded into an ink jet recording apparatus (EB-100 manufactured by Konica Minolta Co., Ltd.) having 256 nozzles × 2 rows of piezo-type ink jet nozzles, and an OPP film (FOR # manufactured by Futamura Chemical Co., Ltd.) was used as a recording material. 20 and a film thickness of 20 μm). The droplet size was about 42 pl so that it could be ejected at a resolution of 360 × 360 dpi (dpi is the number of dots per 2.54 cm) and was driven at a driving frequency of 2 kHz. While preheating with a heater so that the surface of the film was about 60 ° C., printing was performed according to the following ink application sequence, followed by drying (80 ° C./60 seconds).

(Ink application order)
Type A: The second ink is applied after the first ink is applied.
Type B: The first ink is applied after the second ink is applied.
Type C: First ink and second ink are applied simultaneously.

(Viscosity measurement method)
Using an E-type viscometer “V-25 type (manufactured by Toki Sangyo Co., Ltd.)”, measurement was performed (ink temperature 25 ° C.).

(PH measurement method)
Measurement was performed using MM-60R (manufactured by Toa DKK Co., Ltd.) (ink temperature 25 ° C.).

(Surface tension measurement method)
Measurement was performed using a CBVP-Z type (manufactured by Kyowa Interface Science Co., Ltd.) (ink temperature 25 ° C.).

(Evaluation methods)
The following physical properties (1) to (5) were evaluated in a constant temperature and humidity chamber (room temperature: 25 ° C., humidity: 50%) with respect to the ejection properties and the obtained printing.

(1) Evaluation of nozzle clogging and the like after printing 12 continuous sheets.
○: Ink does not adhere around the nozzle, and the nozzle is not clogged.
Δ: Ink adheres around the nozzle, but the nozzle is not clogged.
×: Nozzle clogged.

(2) Breathability (bleed)
○: Ink does not bleed at the boundary between halftone dots and solid portions.
Δ: There is a slight blur at the boundary between halftone dots and solid portions.
X: The dot of a halftone dot and a solid part spread.

(3) Repelling ○: Ink does not repel at halftone dots and solid areas.
Δ: Ink is slightly repelled at halftone dots and solid portions.
X: Ink repels at halftone dots and solid areas.

(4) Solid part reproducibility ○: Ink is reproduced without density unevenness in the solid image printing part.
(Triangle | delta): The density nonuniformity of a solid image printing part is less than 20% with respect to a printing part.
X: Density unevenness of the solid image printing part is 20% or more with respect to the printing part.
The evaluation results are shown in Tables 7-21.

Ink application order type A: Application of the second ink after application of the first ink Type B: Application of the first ink after application of the second ink Type C: Application of the first ink and the second ink simultaneously Ink mixing ratio (mass ratio)
Resin having hydroxy group and / or carboxyl group (solid content) / pantothenic acid polyvalent metal salt (solid content)

Ink application order type A: Application of the second ink after application of the first ink Type B: Application of the first ink after application of the second ink Type C: Application of the first ink and the second ink simultaneously Ink mixing ratio (mass ratio)
Resin without hydroxy and carboxyl groups (solid content) / pantothenic acid polyvalent metal salt (solid content)

As a result, all of the ink sets obtained in Examples 1 to 98 had good bleeding, repelling, and solid portion reproducibility. On the other hand, Comparative Example 1 was an example in which a resin having no hydroxy group and carboxyl group was used as the binder resin in the first ink. Comparative Examples 2 to 6 are examples using a polyvalent metal salt other than the pantothenic acid polyvalent metal salt. However, unlike the examples, the desired effects were not obtained.

Claims

An ink set for ink jet recording using at least two kinds of inks, wherein the first ink contains a coloring material, a resin having a hydroxy group and / or a carboxyl group, a water-soluble solvent and / or water, The water-based ink set for ink-jet recording, wherein the ink contains a pantothenic acid polyvalent metal salt, a water-soluble solvent and / or water.
2. The ink set for water-based inkjet recording according to claim 1, wherein the color material is a pigment, and the resin having the hydroxy group and / or carboxyl group is dispersed in a water-soluble solvent and / or water. *
The aqueous inkjet recording according to claim 1 or 2, wherein the resin having a hydroxy group and / or a carboxyl group is a polyolefin resin, a polyester resin, a polyester urethane resin, an acrylic resin, a vinyl chloride resin, a vinyl acetate resin, or an epoxy resin. Ink set.
The ink set for water-based inkjet recording according to claim 3, wherein the polyolefin resin has a weight average molecular weight of 10,000 or more and 1,000,000 or less and an acid value of 1 to 200 mgKOH / g.
The water-based inkjet recording ink set according to claim 3 or 4, wherein the polyolefin resin is a polyolefin resin having a polyether chain.
The water-based ink set for ink-jet recording according to any one of claims 1 to 5, which prints on a non-absorbent substrate.