JP6155514B2 - Aqueous inkjet composition - Google Patents

Description

  The present invention relates to an aqueous inkjet composition, and more particularly to an aqueous inkjet composition for sign displays.

  Conventionally, in a water-based inkjet composition using a pigment, a pigment as a colorant and a resin as a coating film forming component are separately dispersed in an aqueous medium. In this case, there is a problem of ejection stability in which the head when ink is ejected easily due to the uneven pigment surface, and because the pigment appears on the surface of the coating film after being ejected and dried, rubbing occurs. The problem is poor print quality such as water resistance and water resistance, and the problem of storage stability that the pigment in the aqueous medium tends to settle during storage. Various proposals have been made to solve these problems. For example, Patent Document 1 proposes a resin-dissolved ink in which carbon black or an organic pigment is dispersed using a water-soluble resin as a binder / dispersant, but the print quality of the obtained printed matter is as follows. It was still not enough.

Patent Document 2 proposes a method of encapsulating a colorant as a microcapsule, but there is a problem in that foaming is large due to the influence of a surfactant used at the time of encapsulation, and the jetting characteristics of inkjet are not always sufficient. It was.
Patent Document 3 discloses a method of coating a pigment with a self-water dispersible resin by using a phase inversion emulsification method, and Patent Document 4 further discloses a water-insoluble polymer obtained by phase inversion emulsification. Discloses a method in which the colorant coated with the resin and the resin particles obtained by emulsion polymerization are used in combination. By these methods, the pigment surface is coated with resin, and the non-uniformity of the pigment surface is eliminated to some extent. However, in these methods, since the interaction between the resin and the pigment is insufficient, the pigment There was a problem that it was not fully contained. If the pigment is not sufficiently coated, the surface shape of the pigment particles is still non-uniform, and the above problems of ink ejection stability, print quality, and storage stability cannot always be sufficiently solved. There wasn't.

Japanese Patent Laid-Open No. 03-153775 Japanese Unexamined Patent Publication No. 01-170672 Japanese Patent No.4081693 JP 2006-273891 A

  The present invention has been made in order to solve the above-described problems. No nozzle clogging occurs when printing with an ink jet printer, and a printed matter preferable in terms of print quality is obtained, and the printability is excellent. It is an object of the present invention to provide a water-based inkjet composition.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that the water-insoluble resin has at least one acid functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group, and a phosphoric acid group. An excellent aqueous inkjet composition is obtained by phase inversion emulsification of the resin using (A), a surfactant (B) having a betaine structure, an organic pigment (C), and an organic pigment derivative (D). The present invention has been found and the present invention has been completed.

  A surfactant having a betaine structure is generally used as an additive for controlling permeability to a medium such as an emulsifier for emulsion polymerization, a dispersion stabilizer, or paper or special paper when used in an ink. The present inventors considered that the characteristics of the betaine structure having both an acidic group and a basic group in one molecule could be a good intermediate component when the pigment and the resin have opposite charges. A surfactant having a betaine structure (B) alone does not yield a composition having good dispersion stability. Unexpectedly, when an organic pigment derivative (D) is further added, it can be stably dispersed in an aqueous medium. It was found that a pigment particle dispersion can be obtained. Although not bound by theory, the organic pigment derivative (D) increases the surface charge of the organic pigment (C), and the acidic group or basic group of the surfactant (B) having a betaine structure is formed on the pigment surface. As a result, the pigment surface is covered with the hydrophobic portion of the surfactant (B), and dispersion stability in an aqueous medium is obtained by the hydrophilic portion. Further, by adding the water-insoluble resin (A) having an acid functional group, a part of the acid functional group of the water-insoluble resin (A) is bonded to the basic group on the pigment surface, and the pigment surface is covered with the water-insoluble resin. In addition, it is believed that further dispersion stability in an aqueous medium can be obtained by neutralizing the remaining acid functional groups. The water-based inkjet composition obtained by these methods is excellent in ejection stability and storage stability because the pigment surface is suitably coated with a water-insoluble resin and is stably dispersed in an aqueous medium. It is considered that the printed matter is not clogged, and even in the printed matter, the surface is covered with the water-insoluble resin so that the print quality such as scratching and water resistance is excellent.

  That is, a water-insoluble resin (A) having at least one acid functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group and a phosphoric acid group, a surfactant having a betaine structure (B), an organic A water-based inkjet comprising, as an essential component, a pigment (C) and an organic pigment derivative (D), and an organic pigment (C) coated with a water-insoluble resin (A) having an acid functional group in an aqueous medium, Provided is a water-based inkjet, wherein the water-insoluble resin is a phase-inversion emulsifiable polymer having an acid functional group.

  According to the aqueous inkjet composition of the present invention, by using the surfactant (B) having a betaine structure and the organic pigment derivative (D), a carboxyl group, a sulfonic acid group, a sulfine is formed on the entire surface of the organic pigment (C). A water-insoluble resin (A) having at least one acid functional group selected from the group consisting of an acid group and a phosphate group is conventionally uniformly coated to obtain an aqueous dispersion of organic pigment (C) particles. Thus, when the aqueous inkjet composition of the present invention is printed by an inkjet printer, nozzle clogging does not occur, and a printed matter with improved print quality can be obtained.

Hereinafter, the present invention will be described in detail.
The aqueous inkjet composition of the present invention includes a water-insoluble resin (A) having at least one acid functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group, and a phosphoric acid group, and an interface having a betaine structure The activator (B), the organic pigment (C), and the organic pigment derivative (D) are essential components. Although not bound by theory, in the aqueous inkjet composition of the present invention, the surface of the organic pigment (C) is passed through the organic pigment derivative (D) and the surfactant (B) having a betaine structure. Water-insoluble resin (A) having at least one acid functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group and a phosphoric acid group is more uniformly attached than the conventional one. As a result, it is considered that the coated organic pigment is uniformly dispersed in the aqueous medium. The aqueous medium herein refers to only water or a medium containing water as a main component and optionally containing a volatile organic solvent.

Explanation of each component:

The water-insoluble resin (A) having at least one functional group selected from a carboxyl group, a sulfonic acid group, a sulfinic acid group, and a phosphoric acid group contained in the aqueous inkjet composition of the present invention is a surface of the organic pigment (C). Is used to uniformly coat the surface of the organic pigment (C).
The water-insoluble resin (A) having at least one acid functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group and a phosphoric acid group is synthesized in a volatile organic solvent. A method for producing such a water-insoluble resin (A) having an acid functional group is already known to those skilled in the art. For example, in a volatile organic solvent, a polymerizable monomer having an acid functional group such as a carboxylic acid group and a monomer that can be copolymerized if necessary, and a 2,2′-azobis (2-methylbutyrate) as necessary. Nitrile) and 2,2′-azobis (2,4-dimethylvaleronitrile) in the presence of a known additive such as an initiator to polymerize the acid functional group used in the present invention. A water-insoluble resin (A) can be prepared.

  As the water-insoluble resin (A) having an acid functional group used in the present invention, for example, a (meth) acrylic resin, a styrene resin, a polyester resin, an alkyd resin, a urethane resin, and the like can be suitably listed. . Particularly preferred is a (meth) acrylic resin. The water-insoluble resin (A) having such an acid functional group includes, for example, (meth) acrylic acid ester, at least one polymerizable vinyl monomer selected from styrene, substituted styrene, and the like, and (meth) acrylic acid or vinyl. Produced by copolymerization with sulfonic acid or phosphate ester (meth) acrylate monomers. Here, examples of the (meth) acrylate ester include alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate, and alkyl esters. In order to adjust the hydrophilicity of the obtained water-insoluble resin (A) having a carboxyl group, a (meth) acrylic acid ester containing a hydroxyl group, such as 2-hydroxyethyl (meth) acrylic acid ester, etc. May be used in combination. Further, the water-insoluble resin (A) having at least one acid functional group selected from a carboxyl group, a sulfonic acid group, a sulfinic acid group, and a phosphoric acid group is modified with a polyvalent isocyanate such as hexamethylene diisocyanate as necessary. You may do.

  The acid value of the water-insoluble resin (A) thus synthesized having an acid functional group is 10 to 300, and preferably 40 to 200. The acid value means the number of milligrams (mg) of potassium hydroxide (KOH) necessary to neutralize 1 g of the resin, and is expressed in mg · KOH / g (hereinafter, the unit is abbreviated).

  The acid functional group introduced into the water-insoluble resin (A) is any of a carboxyl group, a sulfonic acid group, a sulfinic acid group, and a phosphoric acid group, and is not particularly limited. And can be used preferably.

  When the acid value of the resin (A) is less than 10, the surface hydrophilicity of the obtained coated organic pigment (C) tends to be poor, and the dispersion stability becomes insufficient. On the other hand, when the acid value exceeds 300, the hydrophilicity of the water-insoluble resin (A) having an acid functional group is remarkably increased, and the organic pigment (C) is covered with the water-insoluble resin (A) having an acid functional group. It becomes insufficient due to swelling and the like, and the coated organic pigments (C) are aggregated and the nozzles are clogged.

  When performing phase inversion emulsification described later, some of the acid groups may be neutralized with an alkaline neutralizing agent. Examples of the neutralizing agent used include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide, basic substances such as ammonia, triethylamine, morpholine, triethanolamine, diethanolamine, Alcohol amines such as N-methyldiethanolamine can be used. The neutralization rate of the water-insoluble resin (A) having at least one acid functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group and a phosphoric acid group is preferably 30 mol%. It may be an equivalent amount to an equivalent amount of 100 mol%.

  The weight average molecular weight in terms of polystyrene measured by gel permeation chromatography of the water-insoluble resin (A) having an acid functional group used is preferably 5,000 to 100,000, more preferably 10,000 to 60,000. When the molecular weight is less than 5,000, phase inversion emulsification is difficult to occur. On the other hand, when the molecular weight is more than 100,000, stability during storage tends to decrease.

  The water-insoluble resin (A) having an acid functional group is preferably 50 parts by mass or more, more preferably 100 parts by mass or more with respect to 100 parts by mass of the organic pigment (C). When (C) is less than 50 parts by mass with respect to 100 parts by mass, the organic pigment (C) is not completely covered with the water-insoluble resin (A), resulting in a broad particle size and good discharge. Stability is not obtained. Furthermore, since the water-insoluble resin (A) is insufficient, the film-forming property of the film is inferior, so that the film physical properties are greatly reduced.

  The surfactant (B) having a betaine structure used in the aqueous inkjet composition of the present invention is an excellent dispersant for stably dispersing the organic pigment (C) for a long period of time, and further has a quaternary ammonium moiety and Since an interaction occurs with the acid group of the water-insoluble resin (A) having an acid functional group, the acid functional group in the organic pigment (C) covered with the surfactant (B) having a betaine structure. When the water-insoluble resin (A) has phase inversion emulsification, it is considered that a dispersion of pigment particles whose surface is uniformly coated with the water-insoluble resin (A) having an acid functional group is obtained.

  The structure of the surfactant (B) having a betaine structure used in the composition of the present invention is not limited as long as it has a betaine structure. However, since a water-based inkjet composition having more excellent dispersion stability can be obtained when the number of adsorption points on the pigment surface is larger, it is preferably a comb polymer, and a comb polymer having a molecular weight of 1000 to 10,000. Is more preferable. When the molecular weight is less than 1000, the surfactant is easily peeled off from the pigment surface during storage, so that the storage stability is lowered. Conversely, when the molecular weight exceeds 10,000, the hydrophilic part becomes large and the usable range is limited. Is done. Examples of the structure of the comb polymer include a polymer having a quaternary ammonium moiety in the main chain and a hydrophilic portion having an acid functional group in the side chain, and a side chain structure consisting of styrene and maleic anhydride. Those having a polymer derivative can be suitably used. Commercially available products can be used for these comb polymers. For example, the conventional polymers described in Japanese Patent No. 4990982, Japanese Patent No. 5122582, Japanese Translation of PCT International Publication No. 2012-509946, etc. It can also be synthesized using a method.

For example, the surfactant (B) having a betaine structure used in the present invention is preferably styrene maleic anhydride resin (SMA) 1000 (Tg = 155, acid value = 465-495, Mw = 5500), As a solvent, for example, a solution prepared by dissolving in an alkoxyalkyl acetate such as methoxypropyl acetate and mixing an amine, for example, JEFFAMINE M-2005 (amine-terminated EO / PO polyether), is equipped with a stirrer and a reflux condenser. By filling a temperature-controlled reaction vessel and reacting the resulting mixture at 20 to 200 ° C., preferably 30 to 170 ° C. for 2 to 10 hours, and then removing methoxypropyl acetate by distillation. Can be manufactured.
The amine used here is characterized by containing an amino group having at least one active hydrogen, and for example, polyalkylene oxide monoamine, N, N-disubstituted diamine or alkanolamine is preferable.

  Specifically, as the surfactant (B) having a betaine structure, commercially available products such as Amphitol 20BS, Amphitol 24B, Amphitol 86B, Amphitol 20YB manufactured by Kao Corporation; EFKA4520, EFKA5063, EFKA6225 manufactured by BSFS; Kemi Japan Co., Ltd. DISPERBYK-106, DISPERBYK-140, DISPERBYK-142, DISPERBYK-145, DISPERBYK-2001, BYK-9076: Daigen Kogyo Seiyaku Co., Ltd. Amorgen S, Amorgen S-H, Amorgen K, Amorgen Examples include LB-C, amorgen CH-H, and amogen HB-C.

  In the aqueous inkjet composition of the present invention, the surfactant (B) having a betaine structure is 1 to 80 parts by mass, preferably 5 to 60 parts by mass with respect to 100 parts by mass of the organic pigment (C). Is preferred. When the amount of the surfactant (B) having a betaine structure is less than 1 part by mass with respect to 100 parts by mass of the organic pigment (C), the dispersion stability of the organic pigment (C) in the medium becomes poor. easy. On the other hand, if it exceeds 80 parts by mass, the water resistance and alcohol resistance of the film are deteriorated, so that the practicality is inferior.

  Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 30, 64, 80 Pigment Red 9, 48 as the organic pigment (C) used in the aqueous inkjet composition of the present invention. 49, 52, 53, 57, 97, 122, 123, 149, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 240, 254, Pigment Yellow 12, 17 , 20, 31, 55, 83, 93, 125, 154, 181 and pigment violet 19, 29, 32, 40, and the like.

  The organic pigment derivative (D) used in the aqueous inkjet composition of the present invention is generally known as described in, for example, JP-A Nos. 2002-294134 and 6-345997. It can be obtained by introducing an acidic or basic functional group into the organic pigment. Examples of the organic pigment here include azo, phthalocyanine, anthraquinone, quinacridone, dioxane, anthrapyrimidine, anthanthrone, indanthrone, flavanthrone, and perinone. Examples of the acidic group to be introduced include a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group. Examples of the basic group include an amine.

In the present invention, the organic pigment derivative (D) is considered to have an effect of increasing the charge of the organic pigment (C) and assisting the adsorption of the surfactant (B) having a betaine structure to the organic pigment (C).
Specific examples of the organic pigment derivative (D) used in the water-based inkjet composition of the present invention include SOLPERSE 5000 manufactured by Lubrizol, SOLPERSE 12000, SOLPERSE 22000, BYK-2100 manufactured by Bicchem Japan. It is mentioned in.
The usage-amount of an organic pigment derivative (D) is 1.0-10.0 mass parts with respect to 100 mass parts of organic pigments (C), for example, Preferably, it is 3.0-7.0 mass parts is there.
When the amount of the organic pigment derivative (D) used is less than 1 part by mass relative to 100 parts by mass of the organic pigment (C), adsorption between the surfactant (B) having a betaine structure and the organic pigment (C) The force is reduced, and it is difficult to stably disperse the organic pigment (C) in the medium for a long period of time. On the other hand, when the amount of the organic pigment derivative (D) exceeds 10 parts by mass, the organic pigment derivative (D) that cannot be adsorbed on the organic pigment (C) is likely to be generated, and the problem of precipitation during storage is likely to occur.
If necessary, a surfactant having no betaine structure can be used in combination.

Hereinafter, the preparation of the aqueous inkjet composition will be described. However, the method for preparing the aqueous inkjet composition is not limited to the embodiment described below.
In producing an aqueous inkjet composition, first, a water-insoluble resin (A) having an acid functional group, a surfactant (B) having a betaine structure, an organic pigment (C), and an organic pigment derivative (D) are volatile. After mixing and stirring in the organic solvent, a dispersion in which the pigment is dispersed in the form of fine particles with a disperser is obtained.
Next, an alkaline neutralizing agent is mixed with the dispersion thus obtained, if necessary, and then water is added to the dispersion while stirring, thereby causing phase inversion emulsification and organic pigment (C ) Is uniformly coated with a water-insoluble resin (A) having an acid functional group by a surfactant (B) having a betaine structure and an organic pigment derivative (D). After phase inversion emulsification, the volatile organic solvent contained in the dispersion may be distilled off.

The dispersion by the disperser is performed so that the particle diameter at a cumulative 50% (number of particles) of the coated organic pigment (C) measured by the dynamic light scattering method is 100 to 1000 nm. Within this range of particle diameter, the coated organic pigment in the resulting aqueous inkjet composition is stably and uniformly maintained in the dispersion.
In the dispersion, for the purpose of adjusting the surface tension and drying properties and various functions, organic solvents other than the above volatile organic solvents, fungicides, preservatives, ultraviolet absorbers, light stabilizers, anti-settling agents, You may mix | blend a thickener, an antifoamer, etc.

  Examples of volatile organic solvents used in the present invention include hydrocarbon solvents such as toluene, xylene, n-hexane, and mineral spirits, alcohol solvents such as methanol, ethanol, isopropyl alcohol, and n-butyl alcohol, Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetate solvents such as methyl acetate, ethyl acetate, propyl acetate, 3-methoxy-3-methylbutanol, 1-methoxy-2-propanol, 3-methoxybutyl Preferable examples include glycol ether solvents such as acetate.

As a disperser used when dispersing the organic pigment (C), for example, a paint shaker, a ball mill, a sand mill, and a nanomill can be preferably listed.
The aqueous inkjet composition of the present invention can be used in various inkjet printers. The aqueous inkjet composition of the present invention is particularly suitable for printing by a large inkjet printer using a large format, for example, printing by an inkjet printer for the purpose of printing on an outdoor printing article such as a sign display. it can.

  The printing surface (ink composition) after inkjet printing forms a dry film by drying at room temperature to several tens of degrees Celsius. In addition, about the base material which can be printed using the water-based inkjet composition of this invention, if a deformation | transformation or a quality change is not carried out on the conditions which dry a printing surface (ink composition), it will not restrict | limit in particular. As such base materials, for example, metal, glass, plastic and other base material surfaces, paper coated with resin on the surface, transparent sheets for overhead projects, outdoor articles such as sign displays, etc. can be suitably listed. it can.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.
Production of water-insoluble resin (A) having carboxyl group as binder:
(Binder Production Example 1)
A premix of 37.5 parts by weight of methyl methacrylate, 4.25 parts by weight of butyl acrylate, 1.75 parts by weight of acrylic acid, and 1.30 parts by weight of 2,2′-azobis (2-methylbutyronitrile) is produced. Then, a volatile organic solvent (methyl ethyl ketone) was charged into a temperature-controlled reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet and a premix feed port. The reaction vessel was heated and maintained at 80 ° C., and the premix was charged at a constant rate over 3 hours 30 minutes under a nitrogen atmosphere. After another 30 minutes, a mixed liquid of 0.30 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) and 1.60 parts of xylene was charged at a constant rate over 2 hours as a boost initiator. Further, after keeping the temperature constant for 2 hours and 30 minutes, 25.5 parts of methyl ethyl ketone was charged in a reaction vessel and cooled. Thereby, the binder 1 was obtained.

(Binder Production Examples 2 to 4)
Various binders shown in Table 1 below were prepared in the same procedure as in Production Example 1 except that the raw materials shown in Table 1 below were used as components.

(Binder Production Example 5)
Except for using the raw materials listed in Table 1 below as components, the synthesis was performed in the same manner as in Production Example 1 until the following Table 1 and the boost initiator were filled, and then hexamethylene was used. Example 1 was repeated except that 0.34 parts by mass of diisocyanate (trade name: Desmodur H: manufactured by Sumika Bayer Urethane Co., Ltd.) was added, and the temperature was kept constant for 2 hours and 30 minutes. 5 binders were obtained.

  About the manufactured binder, the acid value and molecular weight were measured by the following method, respectively, and the following reference | standard evaluated. The results are shown in Table 1.

<Acid value>
Conforms to JIS K 6901 4.3 method.

<Molecular weight>
The properties of the binder polymer are measured by gel permeation chromatography (GPC). Using a mechanical HLC-8220 (Tosoh) equipped with two TSK gel super multipore HZ-M columns, tetrahydrofuran (THF) as an eluent at 40 ° C. and a constant flow rate of 0.350 mL / min, the refractive index ( RI) was determined using a detector. The column was calibrated using polystyrene standards. Samples were prepared by dissolving an amount of polymer solution corresponding to 40 mg dry polymer in 10 mL THF.

Production of surfactant (B) having betaine structure:
(Betaine surfactant 1 production example)
SMA 1000 (styrene maleic anhydride resin Tg = 155, acid value = 465-495 Mw = 5500) 60.0 parts by mass, methoxypropyl acetate 90 g, JEFFAMINE M-2005 (amine-terminated EO / PO polyether) 188 parts by mass, A reaction vessel equipped with a stirrer and reflux condenser and temperature controlled was charged. The mixture was reacted at 180 ° C. for 5 hours. Thereafter, methoxypropyl acetate was removed by distillation. As a result, betaine surfactant 1 was obtained.

Table 1. Example of binder production

Example 1
Cyan pigment (trade name: Blue No. 4: manufactured by Dainichi Seika Kogyo Co., Ltd.) 4.60 parts, surfactant having betaine structure, 1.76 parts, organic pigment derivative (trade name: BYK-2100: BYK 0.15 parts and 75.30 parts of methyl ethyl ketone were mixed to obtain 50 parts of 0.5 mm zirconia beads, and the mixture was subjected to pigment crushing for 6 hours with a paint shaker. An aqueous pigment dispersion was obtained. In this non-aqueous pigment dispersion, 24.30 parts of binder 1 and 0.63 part of dimethylethanolamine were dissolved, and 120.00 parts of ion-exchanged water was added to carry out phase inversion emulsification of the resin. Methyl ethyl ketone in the obtained mixed liquid was distilled off using an evaporator to obtain an aqueous dispersion of an organic pigment coated with a binder. Next, 24.00 parts of diethylene glycol monoisobutyl ether was added to obtain an aqueous inkjet composition.

Examples 2-20, Comparative Examples 1-11
An aqueous inkjet composition was prepared in the same manner as in Example 1 except that the raw materials shown in Table 2 below were used as components. However, for Example 11, the pigment crushing time by the paint shaker was 2 hours, and for Comparative Example 8, the pigment crushing time by the paint shaker was 30 minutes.

Table 2 materials
Organic pigment:
Cyan pigment (trade name: Blue No. 4: manufactured by Dainichi Seika Kogyo Co., Ltd.)
Magenta pigment (trade name: Fastogen Super Magenta RGT: manufactured by DIC)
Surfactant:
Betaine surfactant 2 (trade name: DISPERBYK-2001: manufactured by Big Chemie Japan, Inc .: 46% active ingredient)
Betaine surfactant 3 (trade name: Amorgen K: Daiichi Kogyo Seiyaku Co., Ltd .: 100% active ingredient)
Cationic surfactant (trade name: Katiogen SPA: manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: 100% active ingredient)

Organic pigment derivative Acidic organic pigment derivative 1 (trade name: BYK-2100: manufactured by BYK)
Acidic organic pigment derivative 2 (trade name: Solsperse 22000: manufactured by Lubrizol)

  For the dispersions of Examples 1 to 20 and Comparative Examples 1 to 11, the particle diameter, particle size distribution, ejection stability, printability, water resistance, alcohol resistance, and storage stability were measured by the following methods, respectively. Evaluated by criteria.

<Particle size>
The particle size of 50% cumulative and 95% cumulative particle size of the dispersion after ink conversion was measured using Microtrac UPA (Nikkiso Co., Ltd.). Whether or not ink can be ejected can be evaluated based on the cumulative% value.

<Particle size distribution>
The particle size of the dispersion after ink formation was measured using Microtrac UPA (Nikkiso Co., Ltd.) and evaluated according to the following criteria.
A: The difference between the particle size at 50% cumulative and the particle size at 90% cumulative is less than 2 times. ○: The difference between the particle size at 50% cumulative and the particle size at 90% cumulative is more than twice and within 3 times. : The difference between the particle diameter at 50% cumulative and the particle diameter at 90% cumulative is more than 3 times. As the evaluation result improves, the uniformity of the particle surface can be evaluated.

<Discharge stability>
A solid printing of 1 m × 5 m was performed with a large format inkjet printer, and evaluation was performed based on the following criteria based on the number of flight bends and omissions.
◎: No flying bend and missing ○: Total number of flying bend and missing 1-3: △: Total number of flying bend and missing 4-6 ×: Total number of flying bend and missing 7 or more

<Printability>
Images were printed with a large format inkjet printer and visually evaluated.
◎: Clear printed matter without uneven printing ○: Slightly uneven printing, but no problem in practical use ×: Uneven printed matter with noticeable uneven printing

<Water resistance>
Images were printed with a large format inkjet printer, the film was rubbed with a cotton swab soaked in water, and visually evaluated.
A: No change even when rubbed 200 times with a load of 400 g B: Partially peeled ink when rubbed 200 times with a load of 400 g X: Ink peeled when rubbed 200 times with a load of 400 g, and the substrate was visible

<Alcohol resistance>
Images were printed with a large format inkjet printer, the film was rubbed with a cotton swab soaked in 50% by weight ethanol water, and visually evaluated.
◎: No change even when rubbed 20 times with a load of 400 g ◯: Partially peeled ink when rubbed 20 times with a load of 400 g ×: Ink peeled when rubbed 20 times with a load of 400 g and the substrate was visible

<Storage stability>
After the ink was stored at 60 ° C. for 1 month, the viscosity and particle size were measured and evaluated according to the following criteria.
A: Change in viscosity and particle size after storage at 60 ° C. for 1 month within ± 5% each ○: Change in viscosity and particle size after storage for 1 month at 60 ° C. over 5% and 10% or less respectively ×: Changes in viscosity and particle size after storage for 1 month at 60 ° C are over 10% each

  The evaluation results were as shown in Table 2.

Table 2. Evaluation results of water-based jet ink composition

Table 3. Evaluation results of water-based jet ink composition

Table 4. Evaluation results of water-based jet ink composition

Table 5. Evaluation results of water-based jet ink composition

Table 6. Evaluation results of water-based jet ink composition

Table 7. Evaluation results of water-based jet ink composition

  As is clear from the evaluation results shown in Table 2, the inks of Examples 1 to 20 gave good results for each test item, and good inks were obtained.

Claims (10)

  Water-insoluble having at least one acid functional group selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group and a phosphoric acid group together with a surfactant (B) having a betaine structure and an organic pigment derivative (D) A water-based inkjet composition in which an organic pigment (C) coated with a resin (A) is dispersed in an aqueous medium, and water having the acid functional group with respect to 100 parts by mass of the organic pigment (C) 50 parts by mass or more of insoluble resin (A), 1 to 80 parts by mass of surfactant (B) having the betaine structure, 1.0 to 10.0 parts by mass of organic pigment derivative (D), The acid value (KOH mg / g) of the water-insoluble resin (A) having a group is 10 to 300, and the accumulated organic pigment (C) is 50% cumulative (number of particles) measured by the dynamic light scattering method. In The aqueous ink jet composition, wherein the child diameter of 100 to 1000 nm.   The water-based inkjet composition of Claim 1 which contains 100 mass parts or more of water-insoluble resin (A) which has the said acid functional group with respect to 100 mass parts of said organic pigments (C).   The aqueous inkjet composition according to claim 1 or 2, wherein an acid value (KOH mg / g) of the water-insoluble resin (A) having an acid functional group is 40 to 200.   The aqueous inkjet composition according to any one of claims 1 to 3, wherein the water-insoluble resin (A) having an acid functional group is an acrylic resin.   An ink jet printer using the aqueous ink jet composition according to claim 1.   Printing using the water-based inkjet printer according to claim 5.   A printed matter obtained by printing the water-based inkjet according to claim 5 on a recording medium.   The method for producing an aqueous inkjet composition according to claim 1, wherein the organic pigment in a volatile organic solvent of a surfactant (B) having a betaine structure, an organic pigment (C), and an organic pigment derivative (D). (C) The water-insoluble resin (A) which has the said acid functional group is mix | blended with the dispersion liquid, Then, the phase inversion emulsification is performed by adding water.   The method according to claim 8, wherein the water-insoluble resin (A) having an acid functional group is partially neutralized.   The method according to claim 8, wherein the volatile organic solvent is distilled off after the phase inversion emulsification.