JP5987260B2 - Water-based ink set for inkjet recording - Google Patents

Description

  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. Particularly in recent years, as a recording material, there have been many studies on printing on a non-absorbing substrate such as plastic from printing on a conventional absorbing substrate such as paper, and printing using pigment inks from the viewpoint of weather resistance, among others. Is being studied.

  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 a printing method of the water-based inkjet recording method, which is excellent in image quality and scratch resistance regardless of the ink absorbability of the recording medium with respect to a non-absorbing substrate such as plastic,
A printing method for printing an image by applying color ink, resin ink, and reaction ink is known (see, for example, Patent Document 2). Specifically, a color ink containing a water-insoluble colorant, a water-soluble and / or water-insoluble resin component, a water-soluble solvent, and a surfactant, a water-soluble resin solvent, and water-soluble but not soluble in water. The resin resin solvent contains thermoplastic resin particles that are compatible, and the total content of the resin particles is greater than or equal to the content of the colorant contained in the color ink; a polyvalent metal salt; Three inks of a reactive agent selected from allylamine and its derivatives and a reactive ink containing a surfactant are applied to form an image.
However, this method must prepare at least three kinds of inks, and requires an ink jet apparatus having a high degree of ejection accuracy.

  On the other hand, as a two-component printing method using two types of ink, ink jet recording in which an ink containing an anionic surfactant and a treatment liquid containing an anionic water-soluble polymer are contacted and mixed on the surface of the recording medium Ink sets are known (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 10-119428 JP 2010-115854 A JP 2006-241324 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 without causing image disturbance such as bleeding and intercolor bleeding even when printed on a plastic film. .

The present inventors include an ink jet recording comprising a first pigment ink containing a resin having a hydroxy group and / or a carboxyl group, polyacrylic acid or a crosslinked polymer thereof, a water-soluble solvent and / or water. Water-based ink set.
The above-described problems have been solved by using a two-component water-based ink set for ink-jet recording in combination with a water-soluble solvent and / or a second ink containing water.

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. The water-based ink set for ink jet recording, wherein the second ink contains polyacrylic acid or a cross-linked polymer thereof, a water-soluble solvent and / or water.
A water-based ink set for ink-jet recording comprising a water-soluble solvent and / or water is provided.

  According to the present invention, it is possible to provide an aqueous ink set for ink jet recording that gives a printed matter that is excellent in abrasion resistance immediately after printing without causing image distortion such as bleeding or intercolor bleeding even when printed on a plastic film.

In the aqueous ink set for inkjet recording of the present invention, 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 is polyacrylic acid or A water-based ink set for ink-jet recording comprising the crosslinked polymer, 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.

Although the mechanism is not clear about fast fixing with respect to a printing material by overprinting both inks, the following is estimated.
Polyacrylic acid or its cross-linked polymer triggers to grow into large aggregates by intermolecular hydrogen bonding of resins having hydroxy and / or carboxyl groups, and they are bundled by interactions such as van der Waals forces. Thus, they may be entangled in a mesh pattern, hindering the movement of each other, losing fluidity, and being immobilized on the surface of the printed matter. In particular, when a resin having a hydroxy group and / or a carboxyl group has a proton accepting ability, the interaction between each polymer rather than the interaction between each polymer in an aqueous solution and water molecules hydrated to the polymer in the aqueous solution. Since the interaction is stronger, when a polymer aqueous solution having a carboxylic acid group such as polyacrylic acid or its cross-linked polymer is mixed with an aqueous solution of a resin having proton acceptability, a complex of both is immediately formed and precipitation occurs. . Examples of such polymer complexes by hydrogen bonding are described in, for example, JOURNAL OF POLYMERSCCIENCE, Polymer Chemistry Edition, VOL. 13, 1505-1514 (1975) and Chemical Review No. 40, 186-189 (1983), edited by the Chemical Society of Japan.

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

The resin having a hydroxy group and / or a carboxyl group in the present invention may have at least a resin having a hydroxy group and / or a carboxyl group, such as olefin, acrylic, vinyl chloride, vinyl acetate, and epoxy. Any resin may be used. The acquisition form of the resin which has the said carboxyl group is not specifically limited. In view of ease of handling, an aqueous dispersion of a resin, 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 emulsion in which resin particles such as olefin, urethane, and acrylic are dispersed in water is 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 the range of 5-100 mgKOH / g, More preferably, it is the range of 10-80 mgKOH / g, More preferably, it is the range of 15-60 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.

  Moreover, it is preferable to set suitably the glass transition temperature (henceforth Tg) of resin which has the said hydroxyl group and / or carboxyl group according to the desired use. 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 a 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.

When the resin having a hydroxyl group and / or a carboxyl group used in the present invention is an aqueous dispersion of resin particles such as a resin emulsion, if the average particle size is too large, it causes head clogging and causes ejection 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, the range of 10 nm to 500 nm is preferable, and the range of 10 to 300 nm is particularly preferable.
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 includes, for example, a method in which a monomer and a polymerization initiator are dropped in the presence of an emulsifier to polymerize, an emulsification method by stirring an aqueous resin solution or a water suspension, and the like. It is preferable that it is obtained by. 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.

  Among these, an olefin resin having a hydroxy group and / or a carboxyl group is preferable. The olefin resin having a hydroxy group and / or a carboxyl group used in the present invention can be used without particular limitation as long as it is an olefin resin that can be mixed with water and exist in a uniform state. A resin that can exist in a uniform state when mixed with water is dispersed in the form of fine particles in water (this includes a state in which dispersed particles are extremely small and dispersed in a single molecule), so-called water dispersibility. These resins may be used, and so-called water-soluble and water-soluble resins are also included. Specifically, for example, an olefin resin or a rubber-like material composed of a copolymer or a homopolymer of olefin monomers such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, a surfactant, etc. And a water-dispersible resin composed of a polyolefin component and a hydrophilic component such as an acid.

  Examples of the water dispersible resin composed of the olefin component and a hydrophilic component such as an acid include, for example, ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, which are olefin compounds constituting the olefin component. Olefin monomers and unsaturated carboxylic acid or anhydride thereof which is a monomer containing an acidic group for constituting an acid component, specifically, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, In addition to itaconic anhydride, fumaric acid, crotonic acid and the like, unsaturated dicarboxylic acid half esters, half amides and the like can be mentioned. Alternatively, unsaturated sulfonic acid or the like can be obtained by high-pressure radical copolymerization in the presence of a radical generator.

  In addition, the olefin resin or an olefin resin or rubber-like material made of a copolymer or homopolymer of olefin monomers such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, etc. It can be obtained by grafting a monomer or resin having a hydrophilic group such as.

  Examples of the olefin resin and rubber-like material include propylene-α-butene copolymer, ethylene-propylene-diene copolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-vinyl acetate. Copolymer, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, and the like, and further, a copolymer of propylene-α-olefin and two or more of α-olefin and a conjugated or nonconjugated diene Copolymers, such as ethylene-propylene-butadiene copolymer, ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-ethylidene norbornene copolymer, ethylene-propylene-1.5-hexadiene copolymer, and Copolymers of α-olefin and conjugated or non-conjugated dienes such as propylene-butyl Diene copolymers, propylene-ethylidene norbornene copolymers, etc., monomers such as vinyl monomers and α-olefin copolymers and partially saponified products thereof, and the copolymers described above or 2 of the above-mentioned copolymers A composition composed of more than one species is used. Moreover, the modified olefin resin which introduce | transduced the carboxyl group, the hydroxyl group, or the acid anhydride group etc. into these can also be used. Modification of an olefin resin with an α, β-unsaturated carboxylic acid or an acid anhydride thereof can be easily carried out by an ordinary reaction method.

  For example, in order to introduce a hydrophilic group such as an acidic group using a monomer having an acidic group into the olefin resin, the olefin resin, an α, β-unsaturated carboxylic acid, a (meth) acrylic acid ester monomer or a derivative thereof A solution in which a monomer and a polymerization initiator are mixed and dissolved is subjected to suspension polymerization in water in the presence of a dispersant or an emulsifier, whereby an α, β-unsaturated carboxylic acid and / or an anhydride thereof is converted into an olefin resin. A water-dispersible olefin resin in which a (meth) acrylic acid ester monomer or a derivative monomer thereof is graft-copolymerized can be obtained.

  Further, for example, a copolymer obtained by copolymerizing an unsaturated compound having a reactive group is used as the olefin resin, and the reactive group and a poly (meth) acrylic resin, a polyether resin, a polyvinyl alcohol resin, polyvinyl A water-dispersible olefin resin can also be obtained by reacting and grafting a resin having a hydrophilic group such as a pyrrolidone resin. Examples of the reactive group include a carboxylic acid group, a dicarboxylic anhydride group, and a dicarboxylic anhydride monoester group, a hydroxyl group, an amino group, an epoxy group, and an isocyanate group.

  A core / shell obtained by emulsion polymerization of a radically polymerizable monomer other than an olefin in an aqueous dispersion of the self-emulsifiable olefin polymer, using a self-emulsifiable olefin polymer as the olefin resin. Resin particles having a structure can also be used as the water-dispersible olefin resin of the present invention.

  In making the obtained olefin resin aqueous, a basic compound can be added. There is no restriction | limiting in particular in the said basic compound, Any of an inorganic basic compound represented by alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide, ammonia, or various organic amine compounds can be used. Specific examples of the organic amine compound include triethylamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, and 3-ethoxypropylamine. , 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N- Examples thereof include ethyl morpholine.

The acid value of these olefin resins is preferably 10 mgKOH / g or more and 200 mgKOH / g or less. 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 the range of 5-100 mgKOH / g, More preferably, it is the range of 10-80 mgKOH / g, More preferably, it is the range of 15-60 mgKOH / g.

  The glass transition temperature (hereinafter referred to as Tg) of the olefin resin is preferably set as appropriate depending on the desired application. For example, when printing on a plastic film having flexibility, such as for packaging materials for foods, Tg is preferably not so high because flexibility, that is, flexibility is required. In order to achieve both adhesion to an appropriate film and flexibility, the Tg of the olefin resin is preferably in the range of -80 ° C to 80 ° C, and preferably in the range of -80 ° C to 30 ° C. Particularly preferred. From the same viewpoint, it is preferable to use an olefin resin having a low crystallinity.

The weight average molecular weight (GPC-Mw) of the olefin resin is not particularly limited, but the weight average molecular weight (GPC-Mw) is in the range of 10,000 to 1,000,000, more preferably 20,000 to 700,000. The range is preferable because it is easy to secure a balance of physical properties such as storage stability and viscosity with the water-based inkjet recording ink.
In addition, the weight average molecular weight (GPC-Mw) here shall be calculated | required by GPC measurement on the above-mentioned conditions.

  When the olefin resin is an aqueous dispersion, the particle size is preferably in the range of 5 nm to 1000 nm, and more preferably in the range of 10 nm to 400 nm, from the viewpoint of ink jetting properties.

Of course, a commercial product may be used as the olefin resin.
Specifically, commercially available products include APTLOCK BW-5550 (trade name) manufactured by Mitsubishi Chemical Corporation, “Hardren NA, NZ” series manufactured by Toyobo Co., Ltd., “Arrow Base SA” manufactured by Unitika Ltd. SB, SD, SE, TC, TD ”series, etc.

  The content (% by mass) of the resin having a hydroxy group and / or a carboxyl group in the first ink may be used in the range of 0.5% by mass to 30% by mass based on the total mass of the ink. It is common. Among these, 1% by mass to 10% by mass is preferable.

(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, the pigment used in the black ink is 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 Raven5750, Raven5250, Raven5000, Raven3500, Raven1255, Raven700, etc. manufactured by Columbia, Regal 400R, Regal 330R, Regal 660R, Mull 660R, Mull 660R Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. are Degussa's Color Black FW1, FW2, FW2V, FW18, FW200, S170, U, S150, S35, P , V, 1400U, Special Bla k 6, the 5, 4, 4A, NIPEX150, NIPEX160, NIPEX170, NIPEX180 and the like.

  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.

  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.

  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.

  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; C.I. 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 Acid Brown 4 and 14,

  C. I. Basic Black 2.8; C.I. I. Basic yellow 1, 2, 11, 12, 14, 21, 32, 36; I. B. Basic Orange 2, 15, 21, 22; C.I. I. Basic Red 1, 2, 9, 12, 13, 37; I. B. 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 dyes such as basic brown 1 and 12,

  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 direct 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 Blue 2, 5, 7, 16, 20, 24; Reactable Red 6, 7, 11, 12, 15, 17, 21, 23, 24, 35, 36, 42, 63, 66, 84, 184; C . I. Reactive 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 5, 7; reactive dyes such as Reacteve 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; 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 a particle size usually used for inkjet inks, specifically 50 to 500 nm is preferable, and 50 to 300 nm is more preferable for color ink.

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 polyvinyl alcohols, polyvinylpyrrolidones, acrylic resins such as acrylic acid-acrylic acid ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid. Styrene such as acid 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 acrylic 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. As a commercially available product, Ajinomoto Fine Techno Co., Ltd. product Ajisper PB series, Big Chemie Japan Co., Ltd. Disperbyk series, BYK-series, Ciba Specialty Chemicals EFKA series, etc. can be used.

(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; 1,4-dioxane; 1,2-dimethoxyethane; and the like; amides such as dimethylformamide and N-methylpyrrolidone; 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, and 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 is safe and has 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 penetrant content 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. , And the like salts.

  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 them, 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 Preference is given to alkylolamide, acetylene glycol, oxyethylene adducts of acetylene glycol and polyethylene glycol polypropylene glycol block copolymers.

  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 the 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, it 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, antiseptic | preservative, a viscosity modifier, a pH adjuster, a chelating agent, a plasticizer, antioxidant, an ultraviolet absorber etc. can be added as needed.
For example, as the viscosity modifier, polyelectrolyte gel-forming substances such as alginic acid having a carboxyl group, gellan gum, carrageenan having a sulfate group, agarose and salts thereof can be added. These polyelectrolyte gel-forming substances are preferable because ink viscosity can be rapidly increased during ink-jet recording, that is, when the first ink and the second ink are mixed. .

  The amount of pigment in the ink jet recording ink prepared from the pigment paste is 1 to 20% by mass in order to obtain a sufficient image density and to ensure the 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 polyacrylic acid or its crosslinked polymer)
(Polyacrylic acid)
In the polyacrylic acid used in the present invention, acrylic acid is a main component of the monomer (preferably acrylic acid is 70 mol% or more, more preferably 90 mol% or more, most preferably substantially 100 mol%). Examples of (co) polymers include water-soluble polyacrylic acid. These polyacrylic acids may be copolymerized with other monomers, or may be graft polymerized to other hydrophilic polymers such as starch and polyvinyl alcohol.
The polyacrylic acid used in the present invention is preferably a complete acid type polyacrylic acid having a carboxyl group neutralization rate of 0%, and its weight average molecular weight (GPC-Mw) is 1, in terms of polystyrene. The range of 000 to 100,000 is preferable, and the range of 5,000 to 20,000 is more preferable. Of course, the polyacrylic acid may be a commercially available product. Examples of commercially available products include Aquaric HL415 (trade name, manufactured by Nippon Shokubai Co., Ltd.).

(Polyacrylic acid cross-linked polymer)
As the crosslinked polymer of polyacrylic acid used in the present invention, INCI code: Carbomer (generic name: carboxyvinyl polymer) can be used. The carboxyvinyl polymer is obtained by polymerizing a product obtained by polymerizing acrylic acid and a crosslinking agent copolymerizable therewith in an inert solvent such as n-hexane in the presence of a radical polymerization catalyst. It can be obtained by heating under the solvent and removing the solvent.

  The crosslinking agent in the crosslinked polymer of polyacrylic acid used in the present invention is a monomer having two or more ethylenically unsaturated groups, or a monomer having one or more epoxy groups and one or more ethylenically unsaturated groups, Any solvent that can be dissolved in an inert solvent can be used. Specifically, there are acrylic acid esters, methacrylic acid esters, and allyl ethers having two or more substituted polyols, and the polyol is ethylene glycol, propylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, glycerin, polyglycerin. , Trimethylolpropane, pentaerythritol, sucrose, sorbitol and the like. Other examples include diallyl phthalate, triallyl phosphate, allyl methacrylate, tetraallyloxyethane, triallyl cyanurate, divinyl adipate, vinyl crotonic acid, 1,5-hexadiene, divinylbenzene, glycidyl methacrylate, allyl glycidyl ether, etc. It is done. Among these, preferable results are obtained when polyallyl saccharose is used.

  The cross-linked polymer of polyacrylic acid used in the present invention preferably has a neutralization rate of 0%. Of course, a commercial product may be used as the cross-linked polymer of polyacrylic acid. Examples of the commercially available product include ACPEC HV-504E (trade name, manufactured by Sumitomo Seika Co., Ltd.).

  In addition, the usage-amount of a crosslinking agent is the range of 0.05-10 weight% with respect to acrylic acid, Preferably it is the range of 0.1-3 mass%. The optimum use amount is determined according to various conditions, and when it is added excessively, the three-dimensionalization further proceeds and a water-insoluble gel may be formed. Further, when the amount used is too small, there is no effect, and liquidity similar to that when no crosslinking agent is added is exhibited.

  The polyacrylic acid or its crosslinked polymer is dispersed in a water-soluble solvent and / or water, which is a solvent for the second ink. The average particle diameter of the dispersed resin particles is preferably 5 nm to 1000 nm, and more preferably 10 nm to 400 nm, from the viewpoint of ensuring stable ejection properties.

  The polyacrylic acid or a crosslinked polymer thereof is preferably contained in the second ink in an amount of 1% by mass to 50% by mass in terms of solid content, more preferably in the range of 3% by mass to 30% by mass. A range of 10% by weight is most preferred. If it is less than 1% by mass, there is a problem that sufficient curing cannot be obtained, and if it exceeds 50% by mass, the ejection stability is inferior and the image sharpness may be lowered.

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, Examples include biodegradable films such as polylactic acid films. In particular, a polyester film, a polyolefin film, and a polyamide film are 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 use. For example, in the case of a flexible packaging application, the film thickness is 10 μm to 100 μm as having flexibility, durability, and curl resistance. Preferably there is. More preferably, it is 10 micrometers-30 micrometers.

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 applied 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 in mass ratio. Thus, it is a preferable aspect to apply ink.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited to the following Example at all. In addition, the part in an Example below represents a mass part.

(Preparation example cyan ink)
Stir 20 parts of DIC Corporation Cyan Pigment “FANTOGEN BLUE FSJ-SD”, 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 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-7) and (HC-8).

(Preparation example Yellow ink)
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.
34 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-7).

(Preparation example Magenta ink)
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 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 mixture was filtered through a 0.5 μm filter to obtain magenta inks (M-1) to (M-7) and (HM-8).

(Preparation example Black ink)
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 are stirred. 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, 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-7) and (HK-8).

  The respective compositions are shown in Tables 1 to 9.

(Second ink preparation example)
A second ink was prepared according to the composition in Table 10.

Details of the substances described in Tables 1 to 10 are as follows. Unless otherwise indicated, the reagents were used as they were.
Aptolock BW-5550 (trade name): olefin emulsion (Mitsubishi Chemical Corporation, pH: 8, acid value: 18 mg KOH / g, solid content 30%)
Hardren NA-3002 (trade name): Olefin emulsion (manufactured by Toyobo Co., Ltd., pH: 8, acid value: 33 mg KOH / g, solid content 30%)
Vylonal MD-2000: polyester emulsion (manufactured by Toyobo Co., Ltd., pH: 6, solid content 40%)
Arrow Base TC-4010 (trade name): Polyolefin emulsion (manufactured by Unitika Ltd., pH: 10, acid value: 23 mg KOH / g, solid content 25%)
Arrow Base CB-1200 (trade name): Modified polyolefin resin emulsion (manufactured by Unitika Ltd., pH: 3, solid content 23%)
Hydran AP-40F (trade name): Polyester urethane emulsion (manufactured by DIC Corporation, pH: 7, acid value: 25 mg KOH / g, solid content 22%)
Boncoat WKA-565 (trade name): Polyether aqueous urethane emulsion (manufactured by DIC Corporation, pH: 9, acid value: 16 mgKOH / g, solid content 36%)
Jonkrill 780 (trade name): Acrylic aqueous emulsion (manufactured by BASF Corporation, pH: 8, acid value: 46 mg KOH / g, solid content 48%)
Surfynol 440 (trade name): Alic HL-415 (trade name) manufactured by Air Products Japan Co., Ltd .: Polyacrylic acid polymer aqueous solution (manufactured by Nippon Shokubai Co., Ltd.)
(pH: 2, GPC-Mw: 10,000, solid content 45%)
Aclick YS-100 (trade name): sodium polyacrylate aqueous solution (manufactured by Nippon Shokubai Co., Ltd., pH: 8, GPC-Mw: 6000, solid content 45%)
Akpec HV-504E (trade name): polyacrylic acid cross-linked polymer (cross-linking agent: polyallyl saccharose) (manufactured by Sumitomo Seika Co., Ltd., white solid powder)

＊＊＊ 測定不可能もしくは定量下限以下

*** 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 the blank value, C is the amount of 0.5 mol / l potassium hydroxide aqueous ethanol 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.

(Method for measuring weight average molecular weight (Mw) of a resin having a hydroxyl group and / or a carboxyl group)
Mw of a resin having a hydroxyl group and / or a carboxyl group 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 1-140, Comparative Examples 1-6)
Each ink set was loaded into an inkjet recording apparatus (EB-100 manufactured by Konica Minolta Co., Ltd.) having 256 nozzles × 2 rows of piezo-type inkjet nozzles, and an OPP film (Futamura Chemical Co., Ltd. FOR # manufactured 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.).

(Evaluation method)
The following physical properties (1) to (4) were evaluated in a constant temperature and humidity chamber (room temperature: 25 ° C., humidity: 50%) for the ejection properties and the obtained prints.

(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 11-31.

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) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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): hydroxy group and / or carboxyl group-containing resin (solid content) / polyacrylic acid or its crosslinked polymer (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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 having hydroxy group and / or carboxyl group (solid content) / polyacrylic acid or cross-linked polymer thereof (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)
Comparative Example 1: Resin having no hydroxy group and carboxyl group (solid content)
/ Polyacrylic acid or its crosslinked polymer (solid content)
Comparative Examples 2 to 6: Resin having a hydroxy group and a carboxyl group (solid content)
/ Polyacrylic acid or polymers not belonging to its cross-linked polymer (solid content)

  As a result, the ink sets obtained in Examples 1 to 140 all had good bleeding, repelling, and solid portion reproducibility. On the other hand, Comparative Example 1 is an example using a resin having no hydroxy group and carboxyl group as the binder resin in the first ink, and Comparative Examples 2 to 6 are polymers that do not belong to polyacrylic acid or its crosslinked polymer. Although it was an applied example, none of the desired effects were obtained.

Claims (6)

An ink set for ink jet recording using at least two kinds of inks, wherein the first ink is a hydroxy group selected from the group consisting of a colorant, a polyolefin resin emulsion, a polyester resin emulsion, and a polyurethane resin emulsion; An aqueous dispersion of resin particles having a carboxyl group, a water- soluble solvent and / or water,
The aqueous ink set for inkjet recording, wherein the second ink contains polyacrylic acid or a crosslinked polymer thereof, a water-soluble solvent and / or water. The aqueous ink set for inkjet recording according to claim 1, wherein the second ink contains 1 to 50% by weight of the polyacrylic acid or a crosslinked polymer thereof in terms of solid content. The water-based ink set for ink jet recording according to claim 1 or 2, wherein a glass transition temperature of the resin having a hydroxy group and / or a carboxyl group is in a range of -80 ° C to 80 ° C. 2. The resin having a hydroxy group and / or a carboxyl group, wherein the hydroxyl value of the resin is 30 mg KOH / g or less per resin solid content, and the acid value of the resin is 10 to 200 mg KOH / g per resin solid content. The water-based ink set for inkjet recording according to any one of to 3. The content of the resin having a hydroxy group and / or a carboxyl group in the first ink is in a range of 0.5% by mass to 30% by mass based on the total mass of the ink. The water-based ink set for inkjet recording as described in 2. The water-based ink set for inkjet recording according to any one of claims 1 to 5, which prints on a non-absorbent substrate.