JP2022116600A - Inkjet ink composition and recording method - Google Patents

Abstract

[Problem] To provide an inkjet ink composition capable of obtaining recorded matter having excellent rubbing fastness, hardly generating aggregates, improving storage stability, and improving cleanability of the nozzle surface. thing. A pigment, resin particles, a water-soluble organic solvent, and water are contained, the resin particles have a glass transition temperature of 0° C. or higher, and the water-soluble organic solvent has a normal boiling point of 250. ° C. or more polyhydric alcohol with respect to the total amount of the ink composition, and the ratio (SP1/SP2) of the SP value (SP1) of the resin particles to the SP value (SP2) of the pigment is 1.75 or less. [Selection figure] None

Description

The present invention relates to an inkjet ink composition and a recording method.

The ink jet recording method is capable of recording high-definition images with a relatively simple apparatus, and is rapidly developing in various fields. Among them, various studies have been made on ejection stability and the like. For example, Patent Literature 1 discloses an inkjet ink containing a polycarbonate-based urethane resin as a binder resin for the purpose of improving washing and rubbing fastness.

Japanese Patent Application Laid-Open No. 2019-206628

As in Patent Document 1, the use of resin particles for the purpose of improving fastness to rubbing has been conventionally known. However, when resin particles are used, agglomerates derived from the resin particles are generated, or the resin particles or the like adhere to the head, resulting in a decrease in cleanability of the nozzle surface.

The present invention contains a pigment, resin particles, a water-soluble organic solvent, and water, the resin particles having a glass transition temperature of 0° C. or higher, and the water-soluble organic solvent having a normal boiling point of 250 ° C. or higher with respect to the total amount of the ink composition, and the ratio of the SP value (SP ₁ ) of the resin particles to the SP value (SP ₂ ) of the pigment (SP ₁ /SP ₂ ) is 1.75 or less.

The present invention also provides a recording method comprising a step of ejecting the above-described inkjet ink composition from an inkjet head and depositing it on a recording medium.

1 is a perspective view showing an example of an inkjet recording apparatus according to an embodiment; FIG.

Hereinafter, embodiments of the present invention (hereinafter referred to as "present embodiments") will be described in detail with reference to the drawings as necessary, but the present invention is not limited thereto and the gist thereof. Various modifications are possible without departing from the above. In the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the illustrated ratios.

1. Inkjet Ink Composition The inkjet ink composition of the present embodiment (hereinafter also simply referred to as "ink composition") contains a pigment, resin particles, a water-soluble organic solvent, and water. has a glass transition temperature of 0° C. or higher and contains, as a water-soluble organic solvent, a polyhydric alcohol having a normal boiling point of 250° C. or higher in an amount of 5% by mass or more relative to the total amount of the ink composition, and the SP value of the resin particles The ratio (SP ₁ /SP ₂ ) of (SP ₁ ) to the SP value (SP ₂ ) of the pigment is 1.75 or less.

In conventional inks containing resin particles, aggregates derived from the resin particles may occur, or the resin particles and the like may adhere to the head, resulting in a decrease in cleanability of the nozzle surface. In particular, when soft resin particles are used from the viewpoint of improving the touch and feel of the fabric when printed on the fabric, agglomerates are particularly likely to occur, and storage stability and cleanability are likely to decrease.

In recent years, recording apparatuses having large-capacity ink tanks have become more popular. tends to decline. Furthermore, even in a recording apparatus having a long movable portion of an ink flow path that moves according to the carriage operation, the ink composition in the movable portion is subjected to vibration due to the carriage operation for a long period of time, and aggregates are generated over time. tends to be easy.

On the other hand, in the present embodiment, the resin particles used have a glass transition temperature of 0° C. or higher, contain a predetermined amount of a polyhydric alcohol having a normal boiling point of 250° C. or higher, and the ratio of the SP values of the resin particles and the pigment is When the content is at least the predetermined value, it is possible to obtain a recorded matter having excellent rubbing fastness, to prevent formation of aggregates, to improve the storage stability, and to improve the cleanability of the nozzle surface. Each component will be described in detail below.

1.1. Pigment The pigment is not particularly limited, but for example, furnace black, lamp black, acetylene black, carbon black (CI Pigment Black 7) such as channel black, iron oxide, inorganic pigment such as titanium oxide; Pigments, quinacridonequinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments , quinophthalone-based pigments, anthraquinone-based pigments, thioindigo-based pigments, benzimidazolone-based pigments, isoindolinone-based pigments, azomethine-based pigments, and azo-based pigments. These pigments may be used singly or in combination of two or more.

The pigments described above may be dispersible pigments. As a method for dispersing the pigment, for example, a method of dispersing using a water-soluble resin, a method of dispersing using a surfactant, a method of chemically or physically introducing a hydrophilic functional group to the surface of a pigment particle, dispersing and/or Alternatively, a method of making it soluble, etc., can be mentioned.

The SP value (SP ₂ ) of the pigment is preferably 10 to 25 (cal/cm ³ ) ^0.5 , more preferably 11 to 24 (cal/cm ³ ) ^0.5 , still more preferably 12 to 23 (cal/cm 3 ) 0.5 . cm ³ ) ^0.5 . When the SP value (SP ₂ ) of the pigment is within the above range, the dispersibility in the ink composition is further improved, the generation of aggregates is further suppressed, and storage stability and cleanability tend to be further improved. be.

In addition, in this embodiment, the Hansen solubility parameter is used as the SP value. The Hansen solubility parameter is the solubility parameter introduced by Hildebrand divided into three components, the dispersion term δd, the polar term δp, and the hydrogen bonding term δh, and expressed in a three-dimensional space. In the present invention, the SP value is represented by δ[(cal/cm ³ ) ^0.5 ], and the value calculated using the following formula is used.
δ[(cal/cm ³ ) ^0.5 ]=(δd ² +δp ² +δh ² ) ^0.5

The dispersion term δd, the polar term δp, and the hydrogen bonding term δh have been sought by Hansen and his successors, and are described in detail in Polymer Handbook (fourth edition), VII-698-711. Hansen Solubility Parameter values have also been investigated for many solvents and resins, see, for example, Wesley L. et al. Archer, Industrial Solvents Handbook.

In this embodiment, the SP value is calculated by observing the solubility in a mixed liquid of acetone and water prepared at an arbitrary ratio.

The pigment content is preferably 0.1 to 15% by mass, more preferably 0.5 to 12.5% by mass, still more preferably 2.0 to 10% by mass, relative to the total amount of the ink composition. % by mass. When the pigment content is 0.1% by mass or more, the color developability tends to be further improved, and when the pigment content is 15% by mass or less, the sedimentation property of the pigment tends to decrease. In addition, when the content of the pigment is within the above range, the generation of aggregates is suppressed, and the storage stability and cleanability tend to be further improved.

1.2. Resin Particles The resin particles are not particularly limited, but examples thereof include urethane resin particles, acrylic resin particles, polyester resin particles, and polyethylene resin particles. Among these, urethane resin particles are preferred. By using such resin particles, the rubbing fastness and texture of the obtained recorded matter and the storage stability of the ink composition are further improved, and aggregates are less likely to occur, and cleaning properties tend to be further improved. The resin particles may be used singly or in combination of two or more.

The urethane resin particles are not particularly limited as long as they are resin particles having a urethane bond in the molecule. Polycarbonate-type urethane resins containing carbonate bonds in the chain are mentioned. Among these, a polyether-type urethane resin or a polycarbonate-type urethane resin is preferable, and a polycarbonate-type urethane resin is more preferable. Moreover, anionic urethane resin particles having a carboxy group, a sulfo group, a hydroxy group, or the like are preferable from the viewpoint of improving dispersion stability.

The acrylic resin particles are not particularly limited. and other monomers are copolymerized. Among these, anionic acrylic resin particles are preferred.

The urethane resin particles are not particularly limited, but include, for example, non-crosslinkable urethane resin particles and crosslinkable urethane resin particles having a crosslinkable group. Among these, crosslinkable urethane resin particles are preferred. The crosslinkable group may be one that reacts between crosslinkable groups to form a crosslinked structure, or one that reacts with a functional group different from the crosslinkable group to form a crosslinked structure. good. The use of resin particles having such a crosslinkable group tends to further improve the texture and rubbing fastness of the obtained recorded matter, and the storage stability of the ink composition.

The crosslinkable group as described above is not particularly limited, but may be, for example, a blocked isocyanate group, a silanol group, or protected by a protecting group. Examples of silanol groups include, but are not limited to, triethoxysilyl groups, trimethoxysilyl groups, and tris(2-methoxyethoxy)silyl groups. The crosslinkable group is preferably a blocked isocyanate group from the viewpoint of storage stability and reactivity. A blocked isocyanate is one in which the isocyanate group is blocked with a blocking agent.

The blocking agent blocks and deactivates the isocyanate groups, while regenerating or activating the isocyanate groups after deblocking. Blocking agents include imidazole compounds, imidazoline compounds, pyrimidine compounds, guanidine compounds, alcohol compounds, phenol compounds, active methylene compounds, amine compounds, imine compounds, oxime compounds, and carbamic acid compounds. , urea-based compounds, acid amide-based (lactam-based) compounds, acid imide-based compounds, triazole-based compounds, pyrazole-based compounds, mercaptan-based compounds, bisulfites, and the like. When the resin has a crosslinkable group, a crosslinked structure is formed between the resins, and the fastness to rubbing can be improved.

The glass transition temperature of the resin particles is 0° C. or higher, preferably 20 to 100° C., more preferably 40 to 100° C., still more preferably 60 to 100° C., still more preferably 80 to 100° C. °C. When the glass transition temperature of the resin particles is 0° C. or higher, aggregation between the resin particles or between the resin particles and the pigment is suppressed. Therefore, the generation of aggregates is suppressed, and the storage stability and cleanability are further improved. The glass transition temperature can be measured by a known method using a differential scanning calorimeter or the like.

The SP value (SP ₁ ) of the resin particles is preferably 15 to 25 (cal/cm ³ ) ^0.5 , more preferably 15.5 to 24.5 (cal/cm ³ ) ^0.5 , still more preferably 16 ~24 (cal/cm ³ ) ^0.5 . When the SP value (SP ₁ ) of the resin particles is within the above range, the dispersibility in the ink composition is further improved, so the generation of aggregates is suppressed, and the storage stability and cleanability tend to be further improved. It is in.

Further, the ratio (SP ₁ /SP ₂ ) of the SP value (SP ₁ ) of the resin particles to the SP value (SP ₂ ) of the pigment is 1.75 or less, preferably 0.8 to 1.65, It is more preferably 1.0 to 1.50. When the ratio (SP ₁ /SP ₂ ) is 1.75 or less, the affinity between the pigment as a dispersion and the resin particles is further improved. Therefore, the storage stability of the ink composition is further improved, the generation of aggregates is suppressed, and the cleanability is further improved. The ratio (SP ₁ /SP ₂ ) was calculated between the lowest SP values.

Also, the elongation of the resin particles is preferably 250 to 800%, more preferably 300 to 700%, still more preferably 350 to 600%. When the elongation of the resin particles is 150% or more, the texture of the obtained recorded matter tends to be further improved. In addition, when the elongation of the resin particles is 800% or less, the rubbing fastness of the obtained recorded matter tends to be further improved.

The elongation of the resin particles is obtained by heating the resin particles at 170° C. for 5 minutes to prepare a film having a thickness of about 60 μm, and measuring it under the conditions of a tensile test gauge length of 20 mm and a pulling speed of 100 mm/min. Elongation at break is adopted.

The 100% modulus of the resin particles is preferably 1-25, more preferably 1-20, still more preferably 5-20. When the 100% modulus of the resin particles is 1 or more, the texture of the obtained recorded matter tends to be further improved. Further, when the 100% modulus of the resin particles is 25 or less, the rubbing fastness of the obtained recorded matter tends to be further improved.

As the 100% modulus of the resin particles, the resin particles are heated at 170° C. for 5 minutes to prepare a film having a thickness of about 60 μm, and a tensile test is performed under the conditions of a gauge length of 20 mm and a tensile speed of 100 mm/min. , the value obtained by measuring the tensile stress when the film is stretched 100% with respect to its original length was adopted.

The content of the resin particles is preferably 1.0 to 12% by mass, more preferably 2.0 to 10% by mass, still more preferably 3.0 to 8.0% by mass, relative to the total amount of the ink composition. It is 0% by mass. When the content of the resin particles is 1.0% by mass or more, the rubbing fastness of the obtained recorded matter tends to be further improved. In addition, when the content of the resin particles is 12% by mass or less, the texture of the resulting recorded matter and the storage stability of the ink composition are further improved, the generation of aggregates is suppressed, and the cleanability is further improved. tend to

1.3. Water-Soluble Organic Solvent The water-soluble organic solvent contains a polyhydric alcohol having a normal boiling point of 250° C. or higher, and may contain other solvents. Since resin particles having a glass transition temperature of 0° C. or higher adhere firmly when dried, they tend to lower the cleanability. In this respect, by using a polyhydric alcohol having a normal boiling point of 250° C. or more together with the resin particles, the drying of the ink composition can be suppressed and the cleanability can be improved.

The total content of the water-soluble organic solvent is preferably 5 to 30% by mass, more preferably 7.5 to 25% by mass, still more preferably 10 to 20% by mass, relative to the total amount of the ink composition. is. When the total content of the water-soluble organic solvent is within the above range, the cleanability tends to be further improved.

1.3.1. Polyhydric alcohol with a normal boiling point of 250°C or higher The polyhydric alcohol with a normal boiling point of 250°C or higher is not particularly limited, but examples thereof include glycerin (290°C); triethylene glycol (285°C), tripropylene glycol (273°C) 1 ,6-hexanediol (250°C), 1,7-heptanediol (258°C) and other glycols; diethylene glycol monohexyl ether (260°C), triethylene glycol monobutyl ether (271°C), diethylene glycol ethylhexyl ether (277 °C) and other glycol monoethers. Temperatures in parentheses above are normal boiling points. The above polyhydric alcohols may be used singly or in combination of two or more.

The normal boiling point of the polyhydric alcohol is 250°C or higher, preferably 260 to 350°C, more preferably 270 to 320°C, still more preferably 280 to 300°C. When the normal boiling point is within the above range, the cleanability tends to be further improved.

The content of the polyhydric alcohol having a normal boiling point of 250° C. or higher is 5% by mass or more, preferably 5 to 30% by mass, more preferably 7.5 to 25% by mass, relative to the total amount of the ink composition. and more preferably 10 to 20% by mass. When the content of the polyhydric alcohol having a normal boiling point of 250° C. or higher is 5% by mass or more, the cleanability is further improved.

1.3.2. Other Solvents Other solvents are not particularly limited, but examples include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1, and 1. , 2-hexanediol, 1,4-butanediol, 1,5-pentanediol and other glycols; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, etc. nitrogen-containing solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone; methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2 -butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol.

Other solvents may not be contained, and the content of other solvents is preferably 0 to 15% by mass, preferably 0 to 10% by mass, more preferably 0 to 10% by mass, relative to the total amount of the ink composition. is 0 to 5% by mass.

1.4. Water The water content is preferably 50 to 85% by mass, more preferably 55 to 80% by mass, still more preferably 60 to 75% by mass, relative to the total amount of the ink composition.

1.5. pH Adjusting Agent The ink composition of the present embodiment may further contain a pH adjusting agent. Examples of pH adjusters include, but are not limited to, inorganic acids (e.g., sulfuric acid, hydrochloric acid, nitric acid, etc.), inorganic bases (e.g., lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, etc.), organic bases ( triethanolamine, diethanolamine, monoethanolamine, tripropanolamine), organic acids (eg, adipic acid, citric acid, succinic acid, etc.), and the like. Inclusion of a pH adjuster tends to further improve dispersion stability. The pH adjusters may be used singly or in combination of two or more.

The content of the pH adjuster is preferably 0.01 to 1.5% by mass, more preferably 0.05 to 1.0% by mass, and still more preferably 0% by mass, relative to the total amount of the ink composition. .1 to 0.75% by mass.

1.7. Surfactant The ink composition of the present embodiment may further contain a surfactant. Examples of surfactants include, but are not particularly limited to, acetylene glycol-based surfactants, fluorine-based surfactants, and silicone-based surfactants. Among these, acetylene glycol-based surfactants are preferred.

The acetylene glycol surfactant is not particularly limited, but examples include 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5- selected from alkylene oxide adducts of decyne-4,7-diol and alkylene oxide adducts of 2,4-dimethyl-5-decyn-4-ol and 2,4-dimethyl-5-decyn-4-ol One or more is preferred.

Examples of fluorine-based surfactants include, but are not limited to, perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaine, perfluoroalkyl Fluoroalkylamine oxide compounds are mentioned.

Examples of silicone-based surfactants include polysiloxane-based compounds and polyether-modified organosiloxanes.

The surfactant content is preferably 0.3 to 2.5% by mass, more preferably 0.5 to 2.0% by mass, relative to the total amount of the ink composition. When the content of the surfactant is within the above range, the color developability of the obtained recorded matter and the storage stability of the ink composition tend to be further improved.

1.7. pH
The pH of the ink composition is preferably 11.0 or less, more preferably 10.0 or less, even more preferably 5.0 to 10.0, still more preferably 7.5 to 10.0. is. When the pH is 11.0 or less, the dispersibility of the pigment as a dispersion and the resin particles is further improved. Therefore, the storage stability of the ink composition is further improved, the generation of aggregates is suppressed, and the cleanability tends to be further improved.

2. Recording Method The recording method of the present embodiment includes an ejection step of ejecting the inkjet ink composition from an inkjet head and depositing it on a recording medium, and optionally a treatment liquid depositing step of depositing a treatment liquid. A liquid feeding step of feeding the ink composition to the inkjet head and a wiping step of wiping the nozzle forming surface of the inkjet head may be included.

2.1. Treatment liquid application process The treatment liquid application process is a process in which a treatment liquid composition containing a cationic compound that aggregates the components of the ink composition is applied to the fabric prior to the ejection process. At this time, from the viewpoint of aggregating the components of the ink composition, at least a part of the area where the treatment liquid composition is adhered and the area where the ink composition is adhered are made to overlap.

By providing such a treatment liquid adhesion step, the components of the ink composition tend to aggregate on the surface of the recording medium, and the color development and rub fastness of the obtained recorded matter tend to be further improved.

As a method for applying the treatment liquid, in addition to the method of applying the treatment liquid using an inkjet method, application may be performed using a bar coater, a roll coater, a spray, or the like.

2.2. Liquid Feeding Process In the liquid feeding process, the inkjet ink composition contained in the ink containing body is liquid-fed to the inkjet head through the ink channel. In this embodiment, the ink storage capacity of the ink container is preferably 3 L or more, more preferably 3 to 6 L. The present invention is particularly useful in such a recording apparatus having a large ink storage capacity, since aggregates tend to occur over time and storage stability tends to decrease.

Further, in this embodiment, it is preferable that the ink flow path has an ink flow path movable portion with a length of 1000 mm or more. In such a recording apparatus having a long movable portion, the ink composition in the movable portion is exposed to vibrations caused by the carriage operation for a long period of time, and aggregates tend to occur over time. is particularly useful.

Here, the term "ink channel" refers to a channel for circulating ink in a printing apparatus. The ink channel includes, for example, an ink supply channel for supplying the ink composition from the ink container to the inkjet head, and a channel for circulating the ink to the nozzle opening in the inkjet head.

In addition, the "moving portion of the ink flow path" refers to the movable portion of the ink flow path that moves according to the carriage movement of a serial printer, for example, in the ink supply path for supplying the ink composition from the ink containing body to the inkjet head. Say.

2.3. Ejecting Step The ejecting step is a step of ejecting the inkjet ink composition from an inkjet head and attaching it to a recording medium. An inkjet head is a head that performs recording by ejecting an ink composition toward a fabric. and a nozzle for ejecting the ink composition out of the head. The ejection driving unit is formed using an electromechanical conversion element such as a piezoelectric element that changes the volume of the cavity by mechanical deformation, or an electrothermal conversion element that generates bubbles in the ink by generating heat and ejects the ink. be able to.

Ink jet heads used in the ejection process include a line head that performs recording by a line method and a serial head that performs recording by a serial method.

In the line method using a line head, for example, an inkjet head having a width equal to or greater than the recording width of the recording medium is fixed to the recording apparatus. Then, an image is recorded on the recording medium by moving the recording medium along the sub-scanning direction (conveying direction of the recording medium) and ejecting ink droplets from the nozzles of the inkjet head in conjunction with this movement.

In a serial method using a serial head, for example, an inkjet head is mounted on a carriage that can move in the width direction of a recording medium. An image is recorded on the recording medium by moving the carriage along the main scanning direction (the width direction of the recording medium) and ejecting ink droplets from the nozzles of the head in conjunction with this movement.

The recording medium used in this embodiment is not particularly limited, but examples thereof include an absorbent recording medium, a low-absorbent recording medium, and a non-absorbent recording medium. Among these, an absorbent recording medium is preferable, and a fabric is more preferable.

Fibers constituting the fabric are not particularly limited, and examples thereof include natural fibers such as silk, cotton, wool, nylon, polyester, and rayon, and synthetic fibers.

2.4. Wiping Step The wiping step is a step of wiping the nozzle forming surface of the inkjet head using a wiping member. Examples of the wiping member include elastic materials and liquid-absorbent materials, and specific examples include rubber, cloth, and the like. A cleaning liquid may be used in the wiping step. It should be noted that the use of cloth as the wiping member is preferable because it tends to provide good cleaning properties.

2.5. Other Steps The printing method of the present embodiment may further include, as other steps, a heating step of heating the printing medium after the ejection step. Heating tends to further improve the abrasion resistance of the obtained recorded matter.

3. Recording Apparatus The recording apparatus of the present embodiment includes an ink containing body having an ink containing capacity of 3 L or more, an inkjet head for ejecting the inkjet ink composition, and the inkjet ink composition being fed from the ink containing body to the inkjet head. The ink flow path has an ink flow path movable portion with a length of 1000 mm or more.

As an example of an inkjet recording apparatus, FIG. 1 shows a perspective view of a serial printer. As shown in FIG. 5, the serial printer 200 has a transport section 220 and a recording section 230 . The conveying unit 220 conveys the recording medium F fed to the serial printer to the recording unit 230, and discharges the recording medium after recording to the outside of the serial printer. Specifically, the transport unit 220 has feed rollers and transports the transported recording medium F in the sub-scanning directions T1 and T2.

The recording unit 230 includes an inkjet head 11 that ejects a composition onto the recording medium F sent from the conveying unit 220, a carriage 234 on which the ink jet head 11 is mounted, and the carriage 234 that moves the recording medium F in the main scanning direction S1, A carriage moving mechanism 235 for moving to S2 is provided.

An ink composition is supplied to the inkjet head 11 from an ink container (not shown) through an ink channel 210 having an ink channel movable portion 211 . The ink flow path movable portion 211 follows the movement of the carriage 234 in the main scanning directions S1 and S2.

Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is by no means limited by the following examples.

1. Preparation of Ink Composition Each component was put into a mixture tank so as to have the composition shown in Table 1, mixed and stirred, and filtered through a 5 μm membrane filter to obtain an ink composition of each example. In addition, the numerical value of each component shown in each example in the table represents % by mass unless otherwise specified.

The abbreviations and product components used in Table 1 are as follows.

<Pigment dispersion>
Cyan pigment (PB 15:3, solid content 15% by mass, SP value: 11.0 to 23.4 (cal/cm ³ ) ^0.5 )
Magenta pigment (PR 122, solid content 15% by mass, SP value: 14.0 to 23.4 (cal/cm ³ ) ^0.5 )
<Resin particles>
Resin particles A (Takelac W6020, manufactured by Mitsui Chemicals, 100% modulus: 19, elongation: 480, glass transition temperature: 90°C, SP value: 16.5 to 23.4 (cal/cm ³ ) ^0.5 )
Resin particles B (Takelac WS6021, manufactured by Mitsui Chemicals, 100% modulus: 3, elongation: 750, glass transition temperature: 40°C, SP value: 16.5 to 23.4 (cal/cm ³ ) ^0.5 )
Resin particles C (Takelac W6110, manufactured by Mitsui Chemicals, 100% modulus: 2, elongation: 550, glass transition temperature: -20°C, SP value: 16.5 to 23.4 (cal/cm ³ ) ^0.5 )
Resin particles D (Hydran SFC-55, manufactured by DIC Corporation, 100% modulus: 5, elongation: 600, glass transition temperature: -50°C, SP value: 19.2 to 23.4 (cal/cm ³ ) ^0.5 )
<Water-soluble organic solvent>
Glycerin (normal boiling point 290°C)
Triethylene glycol (normal boiling point 285°C)
<pH adjuster>
Triethanolamine KOH (potassium hydroxide)
<Surfactant>
E1010 (Olfine E1010, manufactured by Nissin Chemical Industry Co., Ltd., acetylene glycol-based surfactant)

1.1. SP Value The SP value range of the pigment and resin particles was calculated by observing the solubility in a mixture of acetone and water prepared at an arbitrary ratio. Also, the ratio (SP ₁ /SP ₂ ) of the SP value (SP ₁ ) of the resin particles to the SP value (SP ₂ ) of the pigment was calculated between the lowest SP values.

1.2. pH
The pH of each ink composition was measured under an environment of 25° C. using a pH meter AS800 manufactured by AS ONE.

1.3. Elongation of resin particles Resin particles are heated at 170° C. for 5 minutes to form a film having a thickness of about 60 μm, and the elongation at break obtained by measuring under the conditions of a tensile test gauge length of 20 mm and a pulling speed of 100 mm/min. was measured to determine the elongation of the resin particles.

1.4. 100% Modulus of Resin Particles Resin particles are heated at 170° C. for 5 minutes to prepare a film with a thickness of about 60 μm, and in a tensile test measured under the conditions of a tensile test gauge length of 20 mm and a pulling speed of 100 mm / min, the film The 100% modulus of the resin particles was obtained by measuring the value obtained by measuring the tensile stress when the resin particles were elongated 100% of their original length.

2. Evaluation method 2.1. Each ink prepared as described above was applied to an inkjet printer (product name "SC-F2000" manufactured by Seiko Epson Corporation) in which the carriage flow path (ink flow path movable part) was extended to 5000 mm using a silicon tube. Free-running evaluation was performed for 10 minutes while the composition was filled and the end of the tube was clipped. After that, the tube stopped at the end was cut off, and the ink composition filled in the tube was taken out. The ink composition taken out was filtered on filter paper, and the number of aggregates was confirmed with a microscope and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: The number of aggregates is less than 10 B: The number of aggregates is less than 10 to 30 C: The number of aggregates is 30 or more

2.2. Cleanability of Nozzle Surface Each ink composition prepared as described above was filled in all rows of the head of an inkjet printer ("SC-F2000" manufactured by Seiko Epson Corporation), and it was confirmed that all rows ejected normally. . After that, the ink jet head was shifted from the standby position and stopped in the printing area, and left in an environment of 40° C. and 20% RH for 3 days. After standing, the ink jet head was returned to the standby position and wiped off with a rubber wiper. Then, the number of times of wiping required until ejection was recovered was counted and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: All nozzles recovered after wiping three times or less.
B: All nozzles recovered when the number of times of wiping was 4 or more and 10 or less.
C: Did not recover even after wiping 11 times or more

2.3. Storage stability Each ink composition prepared as described above was placed in a 50 cc glass sample bottle, sealed, and the glass bottle was placed in a 50°C constant temperature bath and left for 14 days in a 50°C environment. did. After the end of standing, the temperature was sufficiently returned to room temperature, and then the viscosity was measured. The viscosity was determined by adjusting the temperature of the ink composition to 25° C. and reading the viscosity at a shear rate of 200 using a viscoelasticity tester MCR-300 (product name) manufactured by Pysica. Then, the viscosity change rate A after 14 days was calculated with respect to the initial viscosity. Evaluation criteria are as follows.
(Evaluation criteria)
A: Viscosity change rate A is less than ±5% B: Viscosity change rate A is ±5% or more and less than 10% C: Viscosity change rate A is ±10% or more

2.4. Rubbing Fastness A white cotton broadcloth was prepared as a fabric, and a pretreatment agent consisting of 6.7 parts of Unisense 104L (water-soluble cationic polymer: manufactured by Senka Co., Ltd.) and 93.3 parts of water was applied to the cotton broadcloth. After padding with a drawing ratio of 70% by a pad method, the fabric was dried at 120°C for 5 minutes to obtain a pretreated fabric.

Next, using an inkjet printer (product name "SC-F2000" manufactured by Seiko Epson Corporation), each ink composition obtained as described above is attached to the pretreated fabric by an inkjet method, and an image is obtained. formed. As the ink composition, an ink composition after being left at 50° C. for 14 days was used.

In the above image forming process, the resolution was set to 1440×720 dpi, the printing range was set to A4 size, and the color ink composition was solid printed in an amount of 20 g/m ² . After that, using a high-temperature steamer ("HT-3-550" manufactured by Tsujii Senki Kogyo Co., Ltd.), the printed material with an image formed on the pretreated fabric by drying at 160 ° C. for 5 minutes. manufactured. Here, solid printing means landing ink droplets (dots) on all the pixels in the minimum recording unit area defined by the recording resolution.

A color fastness test to rubbing was performed on the printed material of each example using a type I (Crockmeter) tester according to the method specified in ISO-105 X12. Wet rubbing was tested according to the wet test specified in ISO-105 X12 and the stain gray scale was used to evaluate rub fastness. The evaluation criteria were as follows.
(Evaluation criteria)
A: Grade 2-3 or higher B: Grade 2-3 or lower, Grade 2 or higher C: Grade 2 or lower

2.5. Color Development Using a colorimeter Spectrolino manufactured by Gretag, the OD value of each printed fabric prepared in the above rubbing fastness evaluation was measured, and the color development was evaluated according to the following evaluation criteria.
A: 1.4 or more B: 1.3 or more and less than 1.4 C: less than 1.3

DESCRIPTION OF SYMBOLS 11... Inkjet head, 200... Serial printer, 210... Ink channel, 211... Ink channel movable part, 220... Conveying part, 230... Recording part, 234... Carriage, 235... Carriage movement mechanism

Claims (12)

containing a pigment, resin particles, a water-soluble organic solvent, and water,
The resin particles have a glass transition temperature of 0° C. or higher,
As the water-soluble organic solvent, a polyhydric alcohol having a normal boiling point of 250° C. or higher is contained in an amount of 5% by mass or more based on the total amount of the ink composition,
The ratio (SP ₁ /SP ₂ ) of the SP value (SP ₁ ) of the resin particles to the SP value (SP ₂ ) of the pigment is 1.75 or less.
Inkjet ink composition. The SP value (SP ₁ ) of the resin particles is 15 to 25 (cal/cm ³ ) ^0.5 .
The inkjet ink composition of claim 1. The SP value (SP ₂ ) of the pigment is 10 to 25 (cal/cm ³ ) ^0.5 .
3. The inkjet ink composition of claim 1 or 2. pH is 10.0 or less,
The inkjet ink composition according to any one of claims 1-3. The content of the pigment is 0.1 to 15% by mass with respect to the total amount of the ink composition.
The inkjet ink composition according to any one of claims 1-4. The resin particles have a 100% modulus of 1 to 20 and an elongation of 300 to 700%,
The inkjet ink composition according to any one of claims 1-5. The resin particles have a glass transition temperature of 20 to 100°C.
The inkjet ink composition according to any one of claims 1-6. An ejection step of ejecting the inkjet ink composition according to any one of claims 1 to 7 from an inkjet head and attaching it to a recording medium,
Recording method. a wiping step of wiping the nozzle forming surface of the inkjet head with a wiping member;
9. The recording method according to claim 8. A liquid feeding step of feeding the inkjet ink composition contained in an ink containing body having an ink capacity of 3 L or more to the inkjet head through an ink flow path,
10. The recording method according to claim 8 or 9. The ink flow path has an ink flow path movable portion with a length of 1000 mm or more,
11. The recording method according to claim 10. an ink containing body having an ink containing capacity of 3 L or more;
an inkjet head for ejecting the inkjet ink composition according to any one of claims 1 to 7;
an ink flow path for feeding the inkjet ink composition from the ink container to the inkjet head;
The ink flow path has an ink flow path movable portion with a length of 1000 mm or more,
recording device.

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