JP2024123401A - Inkjet ink composition and inkjet recording method - Google Patents

Abstract

[Problem] The objective is to provide an inkjet ink composition and the like that has excellent abrasion resistance and blocking resistance while reducing CO2 emissions. [Solution] An inkjet ink composition that contains a pigment, resin particles, and wax particles, the resin particles containing at least one of plant-derived urethane resin, acrylic resin, and polyester resin, the wax particles containing plant-derived wax, and the biomass degree of the ink solids is 10 to 100%. [Selected Figures] None

Description

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

Inkjet recording methods are capable of recording high-definition images with a relatively simple device, and have made rapid progress in various fields. In the process, various studies have been conducted on improving the performance of inks while taking environmental issues into consideration. For example, Patent Document 1 discloses a copolyester that is composed of 30 and 50 mol % of a first monomer that is an isohexide; 40 and 60 mol % of a second monomer that is an aromatic dicarboxylic acid or a cyclic aliphatic dicarboxylic acid; and 1 and 20 mol % of a third monomer that is an aliphatic diol, and the copolyester has an acid value between 10 and 50.

Special table 2014-514382 publication

However, the inkjet ink composition described in Patent Document 1 tends to have poor abrasion resistance and blocking resistance.

The present invention is an inkjet ink composition that includes a pigment, resin particles, and wax particles, the resin particles including at least one of plant-derived urethane resin, acrylic resin, and polyester resin, the wax particles including plant-derived wax, and the ink solids have a biomass ratio of 10 to 100%.

FIG. 2 is a schematic diagram of a recording apparatus used in the present embodiment. 1 is a table showing the results of the examples. 1 is a table showing the results of the examples.

The following describes in detail an embodiment of the present invention (hereinafter referred to as the "present embodiment"); however, the present invention is not limited to this embodiment, and various modifications are possible without departing from the gist of the present invention.

1. Inkjet Ink Composition The inkjet ink composition according to this embodiment (hereinafter also simply referred to as the "ink composition") contains a pigment, resin particles, and wax particles, the resin particles contain one or more of a plant-derived urethane resin, an acrylic resin, and a polyester resin, the wax particles contain a plant-derived wax, and the biomass degree of the ink solids is 10 to 100%.

Plant-derived resins are used to provide environmentally friendly ink compositions. However, compared to ink compositions using commonly used petroleum-derived resins, these tend to have lower abrasion resistance and blocking resistance, and this tendency is more pronounced when recording on non-absorbent recording media or low-absorbent recording media.

The reason for the low abrasion resistance and blocking resistance is thought to be that plant-derived resins tend to have a lower glass transition temperature (Tg) than petroleum-derived resins. However, the reasons for the low abrasion resistance and blocking resistance are not limited to this.

Therefore, in this embodiment, wax particles containing a plant-derived wax are further added to an ink composition using resin particles containing at least one of plant-derived urethane resin, acrylic resin, and polyester resin. By including wax particles containing a plant-derived wax, the ink coating film after printing becomes smoother, and it is considered that the ink coating film has excellent abrasion resistance and blocking resistance while reducing _CO2 emissions. However, the factors that result in excellent abrasion resistance and blocking resistance while reducing _CO2 emissions are not limited to this.

The biomass degree of the ink composition is 10 to 100%, preferably 15 to 100%, 20 to 100%, 30 to 100%, 40 to 100%, 50 to 100%, 60 to 100%, 70 to 100%, 80 to 100%, or 90 to 100%. When the biomass degree of the ink composition is within the above range, the ink composition has reduced _CO2 emissions. Here, the biomass degree is the dry weight ratio of the biomass raw material used.

Biomass raw materials are organic resources derived from plants and animals, excluding fossil resources. In this embodiment, biomass raw materials include biomass resins, lignins, and pigments derived from plants and animals.

The degree of biomass can be measured by a known method based on the concentration of ¹⁴ C measured by accelerator mass spectrometry (AMS method). More specifically, it can be measured by the method described in the Examples.

1.1. Pigment The ink composition of the present embodiment includes a pigment. The pigment is not particularly limited, but examples thereof include resin-dispersed pigments in which the pigment is dispersed by a resin, and self-dispersed pigments in which the pigment itself has dispersibility. More specifically, examples thereof include natural mineral pigments such as red earth, ocher, green earth, malachite, chalk powder, and graphite; synthetic inorganic pigments such as iron blue, zinc oxide, cobalt blue, emerald green, viridian, titanium white, and iron oxide; organic pigments such as alkali blue, lysol red, disazo yellow, and petroleum-derived carbon black; vegetable charcoal such as bamboo charcoal and binchotan charcoal; carbon black (vegetable oil charcoal) derived from vegetable oils such as castor oil and rosin oil; and animal-derived pigments such as squid ink and octopus ink. Among these, from the viewpoint of reducing _CO2 emissions, natural mineral pigments, synthetic inorganic pigments, vegetable charcoal, vegetable oil charcoal, and animal-derived pigments are preferred, and vegetable charcoal and vegetable oil charcoal are more preferred. The pigments may be used alone or in combination of two or more types.

The pigment content is preferably 1 to 20% by mass, 2 to 15% by mass, or 4 to 10% by mass, relative to the total amount of the ink composition. By having the pigment content within the above range, the ink composition tends to have excellent abrasion resistance and blocking resistance.

1.2 Dispersant The ink composition of this embodiment may contain a dispersant. By containing a dispersant in the ink composition, the pigment can be dispersed well in the ink composition.

Examples of dispersants include lignins, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, sulfur-containing polymers, fluorine-containing polymers, and epoxy resins, among which lignins are preferred from the viewpoints of reducing _CO2 emissions and improving dispersibility. In addition, when vegetable charcoal or vegetable oil charcoal is used as a pigment, these contain lignins as a component and have high affinity with lignins, so that the inclusion of lignins as a dispersant tends to show higher dispersibility.

Lignins are not particularly limited, but examples thereof include lignin and lignin derivatives. Lignin derivatives are not particularly limited, but examples thereof include lignin sulfonic acid, lignin sulfonates (sodium lignin sulfonate, potassium lignin sulfonate, etc.), kraft lignin, and soda lignin. All of these are obtained from black liquor during pulp production, with lignin sulfonic acid being obtained from the sulfite method, kraft lignin being obtained from the kraft method, and soda lignin being obtained from the soda method. However, the methods for obtaining these lignins are not limited to these. The dispersants may be used alone or in combination of two or more types.

The content of the dispersant is preferably 1 to 10% by mass, and more preferably 1 to 5% by mass, based on the total amount of the ink composition.

1.3 Resin Particles The ink composition of this embodiment contains resin particles containing at least one of plant-derived urethane resin, acrylic resin, and polyester resin (collectively referred to below as "plant-derived resin"). By containing the above-mentioned resin particles, the ink composition tends to reduce _CO2 emissions while improving abrasion resistance, blocking resistance, and adhesion to a recording medium.

A plant-derived resin is a resin made from monomers produced only from raw materials derived from plants, excluding fossil raw materials, or monomers produced from raw materials including plant-derived raw materials, excluding fossil raw materials (both are collectively referred to as "plant-derived monomers" below). The plant-derived resin may be a resin made only from plant-derived monomers, or may be a resin made from plant-derived monomers and petroleum-derived monomers.

Examples of plant-derived monomers include, but are not limited to, (meth)acrylic acid, (meth)acrylic acid esters (stearyl methacrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, etc.), acrylonitrile, cyanoacrylate, ethylene glycol dimethacrylate, acrylamide, diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, polypropylene glycol, polyester polyol, polyethylene glycol, polycaprolactone polyol, polycarbonate diol, polybutadiene, etc. Examples of the biomass materials include ethylene polyol, polyether polyol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, 2,2-dimethylolpropionic acid, isosorbide, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone, vinyl pyridine, vinyl carbazole, vinyl imidazole, and vinylidene chloride. The biomass materials may be used alone or in combination of two or more.

The content of the resin particles containing a plant-derived resin is preferably 0.5 to 10.0 mass%, 1.0 to 8.0 mass%, or 1.5 to 5.0 mass%, relative to the total amount of the ink composition. By having the content of the resin particles containing a plant-derived resin within the above range, there is a tendency to improve abrasion resistance, blocking resistance, and adhesion to a recording medium while reducing _CO2 emissions.

1.4 Wax Particles As described above, the ink composition using the plant-derived resin tends to have low rub resistance and blocking resistance. However, by further including wax particles containing a plant-derived wax in the ink composition using the plant-derived resin, the ink composition tends to have excellent rub resistance and blocking resistance while reducing _CO2 emissions.

Plant-derived wax is wax made only from raw materials derived from plants, or wax made from raw materials that contain raw materials derived from plants.

Waxes derived from plants include, but are not limited to, carnauba wax, candelilla wax, beeswax, castor oil wax, rice wax, shellac wax, PHA (polyhydroxyalkanoate) wax, beeswax, sunflower wax, privet wax, and bleached montan wax.

The melting point of the wax particles containing plant-derived wax is preferably 30°C or higher, 40°C or higher, 50°C or higher, 60°C or higher, 70°C or higher, 30 to 190°C, 40 to 180°C, 50 to 170°C, 60 to 160°C, or 70 to 150°C. When the melting point of the wax particles containing plant-derived wax is within the above range, the wax particles tend to have excellent abrasion resistance and blocking resistance.

The content of the wax particles containing a wax derived from a plant is preferably 0.1 to 10.0 mass%, 0.2 to 5.0 mass%, 0.4 to 3.0 mass%, or 0.5 to 1.5 mass%, relative to the total amount of the ink composition. When the content of the wax particles containing a wax derived from a plant is within the above range, there is a tendency for the ink composition to have excellent abrasion resistance and blocking resistance while reducing _CO2 emissions.

The mass ratio (B/A) of the content A of the resin particles containing plant-derived resin to the content B of the wax particles containing plant-derived wax is preferably 0.05 to 1.50, 0.10 to 1.00, 0.20 to 0.90, or 0.30 to 0.85. When the mass ratio (B/A) is within the above range, the abrasion resistance and blocking resistance tend to be excellent.

1.5. Organic Solvent The ink composition of the present embodiment may contain an organic solvent. The organic solvent is not particularly limited, but examples thereof include penetrants and humectants, and specific examples thereof include water-soluble organic solvents such as monohydric alcohols, polyols, and glycol ethers. The organic solvent may be used alone or in combination of two or more kinds.

Examples of monohydric alcohols include, but are not limited to, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, and 2-methyl-2-propanol.

Polyols include, but are not limited to, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and glycerin.

Glycol ethers include, but are not limited to, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, dipropylene glycol monopropyl ether, etc.

Among polyols, polyols with a normal boiling point of more than 280°C are not particularly limited, but examples include triethylene glycol, tetraethylene glycol, and glycerin.

In addition, examples of polyols having a standard boiling point of 280°C or less include, but are not limited to, ethylene glycol, diethylene glycol, pentaethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

The content of the organic solvent is preferably 2 to 35% by mass, 3 to 30% by mass, 5 to 25% by mass, or 10 to 20% by mass, based on the total amount of the ink composition. When the content of the organic solvent is within the above range, the abrasion resistance and blocking resistance tend to be improved.

The content of polyols having a standard boiling point of more than 280°C is preferably 0.0 to 2.0% by mass, 0.0 to 1.0% by mass, 0.0 to 0.5% by mass, or 0.0 to 0.1% by mass, relative to the total amount of the ink composition. By having the content of polyols having a standard boiling point of more than 280°C within the above range, abrasion resistance and blocking resistance tend to be improved.

1.6. Surfactant The ink composition of this embodiment may contain a surfactant. The surfactant is not particularly limited, but examples thereof include acetylene glycol surfactants, fluorine-based surfactants, and polysiloxane-based surfactants. The surfactant may be used alone or in combination of two or more types.

The acetylene glycol surfactant is not particularly limited, but is preferably at least one selected from the group consisting of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and 2,4-dimethyl-5-decyne-4-ol and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol. Commercially available acetylene glycol surfactants are not particularly limited, but include, for example, E series such as Olfin 104 series and Olfin E1010, Surfynol 104 and Surfynol 61 (manufactured by Nissin Chemical Industry Co., Ltd.).

The fluorosurfactant is not particularly limited, but examples thereof include perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl betaine, and perfluoroalkyl amine oxide compound. The commercially available fluorosurfactant is not particularly limited, but examples thereof include S-144, S-145 (manufactured by Asahi Glass Co., Ltd.); FC-170C, FC-430, and Fluorad-FC4430 (manufactured by Sumitomo 3M Limited); FSO, FSO-100, FSN, FSN-100, and FS-300 (manufactured by Dupont); and FT-250 and 251 (manufactured by Neos Co., Ltd.).

Examples of silicone surfactants include polysiloxane compounds, polyether-modified organosiloxanes, etc. Commercially available silicone surfactants are not particularly limited, but specific examples include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, and BYK-349 (manufactured by BYK Japan KK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (manufactured by Shin-Etsu Chemical Co., Ltd.).

The content of the surfactant is preferably 0.1 to 5.0% by mass, 0.2 to 2.0% by mass, or 0.5 to 1.5% by mass, based on the total amount of the ink composition.

1.7. Water The water contained in the ink composition of the present embodiment is not particularly limited, and examples thereof include ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, etc. In the present embodiment, the term "water-based ink" refers to an ink composition that contains water as a main solvent component.

The water content is preferably 60 to 90% by mass, and more preferably 65 to 80% by mass, based on the total amount of the ink composition.

1.8. Other Components In addition to the above-mentioned components, the ink composition of the present embodiment may contain other known components that can be used in conventional ink compositions. Examples of the other components include, but are not limited to, a penetrant, a humectant, a dissolution aid, a viscosity adjuster, a pH adjuster, an antioxidant, a preservative, a corrosion inhibitor, a chelating agent for capturing a specific metal ion that affects dispersion, other additives, and organic solvents other than those mentioned above. The other components may be used alone or in combination of two or more kinds. Examples of the penetrant include, but are not limited to, 1,2-hexanediol. Examples of the humectant include, but are not limited to, propylene glycol. Examples of the chelating agent include, but are not limited to, EDTA2Na (disodium edetate).

2. Method for Producing Ink Composition The method for producing the ink composition of this embodiment is not particularly limited, but may be, for example, a method for producing the ink composition of this embodiment by mixing the above-mentioned components. Alternatively, in the method for producing the ink composition of this embodiment, a pigment dispersion liquid may be prepared by dispersing the pigment and the resin particles in water, and the obtained pigment dispersion liquid may be mixed with the other above-mentioned components.

The pigment dispersion may be prepared in advance before preparing the ink composition, or may be prepared by mixing and dispersing it simultaneously with the other components when preparing the ink composition.

The pigment dispersion is not particularly limited, but may be obtained, for example, by mixing the pigment, resin particles, and water with a sand grinder. The beads used in this case may be, for example, zirconia beads with a diameter of 0.5 mm, and the diameter and material are appropriately selected based on the desired physical properties. The dispersion processing time using the sand grinder is preferably 0.5 to 2.0 hours, and 0.5 to 1.5 hours.

3. Recording Medium The recording medium used for recording with the ink composition of the present embodiment is not particularly limited, but examples thereof include absorbent recording media, low absorbent recording media, and non-absorbent recording media.

The ink composition of this embodiment contains wax particles that contain plant-derived wax, so it tends to have excellent abrasion resistance and blocking resistance even when recording on a non-absorbent recording medium or a low-absorbent recording medium.

Absorbent recording media include, but are not limited to, ordinary paper such as electrophotographic paper that has high ink permeability, inkjet paper (paper specifically for inkjet printers that has an ink absorbing layer made of silica particles or alumina particles, or an ink absorbing layer made of hydrophilic polymers such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP)), and fabrics.

Low-absorbency recording media are not particularly limited, but examples include art paper, coated paper, cast paper, etc., which are used in general offset printing and have relatively low ink permeability.

Non-absorbent recording media include, but are not limited to, plastic films and plates such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, polyurethane, etc.; metal plates such as iron, silver, copper, aluminum, etc.; metal plates and plastic films produced by vapor deposition of these metals, alloy plates such as stainless steel and brass, and recording media in which a plastic film such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, polyurethane, etc. is adhered (coated) to a paper substrate.

4. Inkjet Recording Method The inkjet recording method of the present embodiment includes an ink deposition step of ejecting the ink composition of the present embodiment from an inkjet head and depositing it on a recording medium, and may also include other steps, such as a transport step of transporting the recording medium, as necessary.

In the ink deposition process, the ink composition of the present embodiment is ejected from an inkjet head and deposited on a recording medium. More specifically, a pressure generating means provided in the inkjet head is driven to eject the ink composition filled in the pressure generating chamber of the inkjet head from a nozzle.

Inkjet heads used in the ink deposition process include line heads that perform recording using a line method and serial heads that perform recording using a serial method.

In the line method using a line head, for example, an inkjet head with a width equal to or greater than the recording width of the recording medium is fixed to the recording device. The recording medium is then moved along the sub-scanning direction (the direction in which the recording medium is transported), and ink droplets are ejected from the nozzles of the inkjet head in conjunction with this movement to record an image on the recording medium.

In the serial method using a serial head, for example, the inkjet head is mounted on a carriage that can move in the width direction of the recording medium. The carriage is then moved along the main scanning direction (the width direction of the recording medium), and ink droplets are ejected from the nozzles of the inkjet head in conjunction with this movement to record an image on the recording medium.

4.2. Transporting Step The inkjet recording method of this embodiment may include a transporting step. In the transporting step, the recording medium is transported in a predetermined direction within the recording device. More specifically, the recording medium is transported from a paper feed section to a paper discharge section of the recording device using a transport roller or a transport belt provided within the recording device. During the transporting process, the ink composition ejected from the inkjet head adheres to the recording medium, forming a recorded matter. The ink adhesion step and the transporting step may be performed simultaneously or alternately.

5. Recording Device As an example of an inkjet device, a perspective view of a serial printer is shown in Fig. 1. As shown in Fig. 1, the serial printer 20 includes a transport unit 220 and a recording unit 230. The transport unit 220 transports the recording medium F fed to the serial printer to the recording unit 230, and ejects the recording medium after recording outside the serial printer. Specifically, the transport unit 220 has feed rollers and transports the fed recording medium F in the sub-scanning direction T2.

The recording unit 230 also includes a carriage 234 carrying an inkjet head 231 having nozzles that eject ink compositions onto the recording medium F sent from the transport unit 220, and a carriage movement mechanism 235 that moves the carriage 234 in the main scanning directions S1 and S2 of the recording medium F.

In the case of a serial printer, an inkjet head 231 with a length smaller than the width of the recording medium is provided, and the head moves to perform recording in multiple passes. In a serial printer, the head 231 is mounted on a carriage 234 that moves in a predetermined direction, and the head moves with the movement of the carriage to eject the ink composition onto the recording medium F. In this way, recording is performed in two or more passes. A pass is also called a main scan. A sub-scan is performed between passes to transport the recording medium. In other words, main scans and sub-scans are performed alternately.

The inkjet device of this embodiment is not limited to the serial printer, but may be the line printer described above. A line printer is a printer that records on a recording medium in a single scan using a line head, which is an inkjet head that has a length equal to or greater than the recording width of the recording medium.

The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples.

1. Preparation of pigment dispersion 1.1. Preparation of pigment dispersion not containing dispersant (self-dispersing pigment) 10 g of the pigment shown in Figures 2-3 and 3.41 g of p-amino-N-benzoic acid were thoroughly mixed with 72 g of ion-exchanged water, and then 1.62 g of nitric acid was dropped thereto and stirred at 70 ° C. Then, a solution of 1.07 g of sodium nitrite dissolved in 5 g of water was added and further stirred for 1 hour. The obtained slurry was filtered with qualitative filter paper No. 2 (manufactured by Advantec Toyo Co., Ltd.), the pigment particles were thoroughly washed with water, and dried in an oven at 90 ° C., and water was added to the pigment to prepare a pigment dispersion with a pigment concentration of 10 mass %.

1.2. Preparation of pigment dispersion containing dispersant (resin-dispersed pigment) 10 parts by mass of the pigment shown in Figures 2 and 3 and 5 parts by mass of a dispersant were thoroughly mixed in 50 parts by mass of ion-exchanged water, and the mixture was dispersed using a sand grinder for 1 hour. After that, coarse particles were removed by centrifugation, and the mixture was filtered under pressure using a microfilter (manufactured by Fujifilm) with a pore size of 3.0 μm to obtain a pigment dispersion with a pigment concentration of 10% by mass in which the pigment was dispersed by the dispersant.

2. Preparation of Inkjet Ink Composition The resulting pigment dispersion and the remaining components were mixed in a mixing tank so as to obtain the composition shown in Figures 2 and 3, to obtain ink compositions of Examples and Comparative Examples. The numerical values of each component shown in each example in the figures represent mass % unless otherwise specified. The contents (mass %) of pigment, dispersant, resin particles, and wax particles represent solids concentrations.

The materials shown in Figures 2-3 are as follows:
<Pigments>
・Binchotan charcoal (Binchotan charcoal, manufactured by Kiriya Chemical Co., Ltd.)
Petroleum-derived carbon black (C.I. Pigment Black 7, manufactured by Mitsubishi Chemical Corporation)
<Dispersant>
・Sanex P252 (manufactured by Nippon Paper Industries Co., Ltd., sodium lignosulfonate)
Joncryl 61J (BASF, styrene acrylic polymer)
<Penetrating agent>
・1,2-Hexanediol (Osaka Organic Chemical Industry Co., Ltd.)
<Surfactant>
・BYK349 (manufactured by BYK Japan)
<Other ingredients>
Propylene glycol (moisturizing agent; manufactured by Kanto Chemical Co., Ltd.)
EDTA2Na (chelating agent; manufactured by Kanto Chemical Co., Ltd.)

<Resin Particles>
Urethane resin particles 1
In a round-bottom flask equipped with a stirrer, a thermometer, a water divider and a nitrogen gas inlet tube, 18 parts by mass of neopentyl glycol (biomass degree: 40%), 14 parts by mass of 1,3-propanediol (biomass degree: 100%), 14 parts by mass of adipic acid (biomass degree: 0%), 54 parts by mass of sebacic acid (biomass degree: 100%) and 0.002 parts by mass of tetrabutyl titanate were charged, and esterification was carried out for 8 hours at 230°C under a nitrogen stream while removing water generated by condensation. After confirming that the acid value of the polyester was 15 or less, the degree of vacuum was gradually increased by a vacuum pump to terminate the reaction. As a result, a polyester polyol (A1) having a number average molecular weight of 2000, a hydroxyl value of 56.1 mgKOH/g, an acid value of 0.3 mgKOH/g and a biomass degree of 75.2% was obtained. The hydroxyl value and acid value were calculated according to the method described in JIS K0070.

Next, in a reactor equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer, and a thermometer, 121.2 parts by mass of polyester polyol A1, 115.4 parts by mass of polyethylene glycol having a number average molecular weight of 2000, 30.1 parts by mass of 2,2-dimethylolpropionic acid, and 250.0 parts by mass of methyl ethyl ketone (MEK) were mixed while introducing nitrogen gas, and 90.6 parts by mass of isophorone diisocyanate were dropped over 1 hour while stirring, and the mixture was reacted at 80°C for 4 hours to obtain a terminal isocyanate prepolymer, and a terminal isocyanate prepolymer solution was obtained. A mixture of 2.7 parts by mass of 2-aminoethylethanolamine and 150 parts by mass of isopropanol (IPA) was gradually added to the obtained terminal isocyanate prepolymer at room temperature, and the mixture was reacted at 40°C for 2 hours to obtain a solution-type polyurethane resin solution. Next, 38.1 parts by mass of 10% ammonia water and 801.4 parts by mass of ion-exchanged water were gradually added to the solution-type polyurethane resin solution to neutralize and dissolve it in water, and then MEK and IPA were distilled off under reduced pressure, and water was added to adjust the solids concentration, obtaining a solution of urethane resin particles 1 with a solids concentration of 30% by mass. The biomass degree of this urethane resin particle 1 was 25%.

Urethane resin particles 2
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 195 parts by mass of polyether polyol (Cerenol H2000, number average molecular weight 2000, manufactured by DuPont Co., Ltd.), 145 parts by mass of isophorone diisocyanate, 26 parts by mass of 2,2-dimethylolpropionic acid, and 28 parts by mass of 1,4-cyclohexanedimethanol were reacted in methyl ethyl ketone to obtain an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular terminal.

Next, 13.3 parts by mass of a 25% aqueous ammonia solution was added to neutralize some or all of the carboxyl groups of the urethane prepolymer, and 727 parts by mass of ion-exchanged water and 9.1 parts by mass of an 80% aqueous hydrazine solution as a chain extender were then added and thoroughly stirred to obtain an aqueous dispersion of urethane resin. The mixture was then aged and desolvated to obtain urethane resin particles 2 with a solids concentration of 40% by mass. The biomass degree of these urethane resin particles 2 was 60%.

Acrylic resin particles 1
In a reaction vessel equipped with a thermometer, reflux condenser, stirrer, dropping funnel, etc., 237 g of ion-exchanged water and 3 g of Phosphanol RD-720 (Toho Chemical Co., Ltd., phosphoric ester surfactant) were added, and the mixture was heated to 70 ° C. to obtain a solvent. Next, 288 g of stearyl methacrylate (N-Jelve CM-18, New Japan Chemical Co., Ltd.), 48 g of 2-hydroxyethyl methacrylate (Light Ester HOM, Kyoeisha Chemical Co., Ltd.), and 144 g of methyl methacrylate (Acryester M, Mitsubishi Chemical Co., Ltd.) were mixed, and 5.4 g of 2,2'-azobisisobutyronitrile (AIBN, Otsuka Chemical Co., Ltd.) was added as a polymerization initiator and dissolved in the resulting monomer mixture. The monomer mixture thus prepared was placed in a dropping funnel, and 1/4 of the amount was added to the reaction vessel, and the remainder was dropped over 1.5 hours. The mixture was further aged at 70 ° C. for 4 hours to obtain a polymer solution. When 2.5 parts by mass of 28% by mass ammonia water was added to the obtained polymer solution, acrylic resin particles 1 having a weight average molecular weight of 57000 were obtained. The biomass degree of these acrylic resin particles 1 was 49%.

Polyester resin particles 1
In a three-necked round-bottom flask equipped with a Dean-Stark trap, 0.21 mol of isosorbide (30.7 g), 0.04 mol of 1,4-butanediol (3.6 g), and 0.25 mol of 1,4-cyclohexanedicarboxylic acid (43.9 g) were introduced under a nitrogen atmosphere to prepare a mixture. The mixture was heated at 180° C., and 2-ethylhexanoic acid tin (II) salt was added to the molten mixture. The reaction mixture was stirred at 230° C. for 3.5 hours. Then, water produced by the (poly)condensation reaction was removed from the Dean-Stark trap. The reaction mixture was further stirred in vacuum (10 ⁻² mbar or less) at 230° C. for 3.5 hours. The slightly yellow transparent product thus obtained was cooled to room temperature (25° C.) under nitrogen. The biomass degree of the polyester resin particles 1 thus obtained was 99%.

Urethane resin particles 3
A simple pressurized reaction apparatus equipped with a stirrer and a heater was charged with 65.2 parts by mass of PTMG2000 (manufactured by Mitsubishi Chemical Corporation), which is polytetramethylene ether glycol, 3.3 parts by mass of 1,4-butanediol, 4.8 parts by mass of 2,2-dimethylolpropionic acid, 26.7 parts by mass of isophorone diisocyanate, and 54 parts by mass of methyl ethyl ketone, and the mixture was stirred at 70°C for 12 hours to carry out a urethanization reaction, producing a methyl ethyl ketone solution of a urethane prepolymer having isocyanate groups.

Next, 3.6 parts of triethylamine was added to homogenize the mixture, and then 263 parts of ion-exchanged water was added while stirring at 200 rpm to disperse the polyurethane prepolymer in water. The resulting dispersion was heated to 50°C and stirred for 4 hours to carry out a chain extension reaction with water, and was further heated to 60°C under reduced pressure to distill off the methyl ethyl ketone. Then, 3.0 parts by mass of water and DOWSIL 401LS (manufactured by Dow Toray Co., Ltd.) were added to adjust the solids concentration to 30% by mass, thereby obtaining urethane resin particles. The biomass degree of these urethane resin particles was 0%.

<Wax particles>
Carnauba wax 27.5g of warm water, 2.5g of emulsifier (BYK348, silicon surfactant, manufactured by BYK Japan Co., Ltd.), and 5g of carnauba wax (Yamakatsu Sangyo Co., Ltd., melting point 80°C) were put into a container, and 135g of zirconia beads with a diameter of 1mm were used in a rocking mill, and the mixture was stirred at 60Hz for 3 hours to disperse the carnauba wax in water, thereby preparing a carnauba wax emulsion with a solid content concentration of 35% by mass (volume average particle size D50: 300nm). The biomass degree of the wax particles containing carnauba wax obtained in this way was 80%.

The volume average particle diameter D50 was measured by dynamic light scattering. The measuring device used was an ELSZ-1000 (manufactured by Otsuka Electronics Co., Ltd.).

Rice wax Wax particles containing rice wax were prepared in the same manner as for the wax particles containing carnauba wax, except that rice wax (manufactured by Yamakei Sangyo Co., Ltd., melting point 75°C) was used instead of carnauba wax in the preparation method for the wax particles containing carnauba wax. The biomass degree of the wax particles containing rice wax thus obtained was 80%.

Castor oil wax Wax particles containing wax derived from castor oil were prepared in the same manner as in the preparation of wax particles containing carnauba wax, except that in the preparation method of wax particles containing carnauba wax, a wax derived from castor oil (manufactured by Yamakatsu Sangyo Co., Ltd., ITOHWAX J-630, 12-hydroxystearic acid amide, melting point 135°C) was used instead of carnauba wax. The biomass degree of the wax particles containing wax derived from castor oil thus obtained was 80%.

Beeswax Wax particles containing beeswax were prepared in the same manner as in the preparation of wax particles containing carnauba wax, except that beeswax (manufactured by Yamakei Sangyo Co., Ltd., melting point 63°C) was used instead of carnauba wax in the preparation method of wax particles containing carnauba wax. The biomass degree of the wax particles containing beeswax thus obtained was 80%.

Polyethylene wax Wax particles containing polyethylene wax were prepared in the same manner as in the preparation of wax particles containing carnauba wax, except that polyethylene wax (manufactured by San Nopco Ltd., Nopcomal MS-40, melting point 79°C) was used instead of carnauba wax in the preparation method of wax particles containing carnauba wax. The biomass degree of the wax particles containing polyethylene wax thus obtained was 0%.

3. Evaluation A printed material was prepared by printing the ink composition at 100% duty on a corona-treated OPP film (Futamura Chemical Co., Ltd., FOS-AQ#60) using an inkjet ink device (Seiko Epson Corporation, "PX-G930") modified with a heated platen under conditions of a dot weight of 13 ng, a recording resolution of 720 x 720 dpi, and a platen temperature of 55°C, and then drying at 90°C for 10 minutes. Of the evaluations described below, evaluations of abrasion resistance, adhesion, and blocking resistance were carried out on the printed material.

3.1. Biomass Degree The biomass degree of each component of the ink composition was calculated based on the concentration of ^14C , which is an isotope of ^12C , and the concentration of ^14C was measured by accelerator mass spectrometry (AMS). The biomass degree of the solid content of the ink composition was calculated and evaluated based on the biomass degree of each component of the solid content of the ink composition. Specifically, it was calculated using the following formula.
(Biomass ratio of each component × mass%) / (sum of mass% of each component)
*The components referred to here are pigment, dispersant, resin particles, and wax particles.
[Evaluation Criteria]
A: Biomass ratio is 40% or more.
B: Biomass degree is 20% or more and less than 40%.
C: Biomass degree is 10% or more and less than 20%.
D: Biomass degree is less than 10%.

3.2. Abrasion resistance Based on JIS L0849 2013, the test was performed using a Gakushin-type abrasion resistance evaluation device AB-301 manufactured by Tester Sangyo. The abrasion resistance test includes a dry abrasion test using dry cotton wool and a wet abrasion test using wet cotton wool, and both tests were performed. The dry abrasion test was performed under the condition of 100 reciprocations with a load of 200 g, and the wet abrasion test was performed under the condition of 10 reciprocations with a load of 200 g. The above-mentioned printed portion having a size of 1.0 inch x 0.5 inch was formed on the above-mentioned printed matter, and one day after recording, the above-mentioned printed portion was pressed against the cotton wool to evaluate it. Thereafter, the stains on the cotton wool, the stains on the non-printed portion, and the peeling of the above-mentioned printed portion were visually confirmed, and the abrasion resistance was evaluated according to the evaluation criteria shown below.
[Evaluation Criteria]
A: There is no stain on the gold leaf cotton or on the non-printed areas, and the printed areas are not peeled off.
B: There is little staining of the gold leaf cotton and non-printed areas, and the printed areas are hardly peeled off.
C: There is staining of the gold leaf cotton and non-printed areas, and the printed areas have peeled off.

3.3. Adhesion A cross-cut test in accordance with JIS K5600 was performed on the above-mentioned prints, and the remaining state of the printed area on the film and the state of transfer onto the tape were observed, and the adhesion was evaluated according to the following evaluation criteria.
[Evaluation Criteria]
A: The printed portion of the film was not peeled off, and was not transferred to the tape.
B: Peeling of the printed area of the film is 5% or less.
C: Peeling of the printed area of the film is greater than 5%.

3.4. Blocking resistance The above-mentioned printed portion was formed in a size of 5 cm x 5 cm on the above-mentioned printed matter, and the above-mentioned printed portion was cut out from the above-mentioned printed matter to prepare a sample for evaluating blocking resistance. Then, the non-corona-treated side of an unprinted corona-treated OPP film (Futamura Chemical Co., Ltd., FOS-AQ#60) of the same size as this sample was placed on the recording side of the above-mentioned sample, and a pressure of 10 kg/ ^cm2 was applied at 50°C for 24 hours, and the film and the above-mentioned sample were then peeled off, and the degree of peeling of the printed portion and the sense of resistance were evaluated.
[Evaluation Criteria]
A: The printed portion was not peeled off from the printed matter at all, and no resistance was felt when peeled off.
B: Peeling of the printed part from the printed matter accounts for 10% or more and less than 50% of the entire printed part.
C: Peeling of the printed part from the printed matter accounts for 50% or more of the entire printed part.

4. Evaluation Results From the evaluation results shown in Figures 2 to 3, it was found that all of Examples 1 to 12 were excellent in abrasion resistance, adhesion, and blocking resistance while reducing CO2 emissions, compared to Comparative Examples 1 and 4, which did not use resin particles containing a plant-derived resin and used resin particles not containing a plant-derived resin, Comparative Examples 3 and ₆ , which did not use resin particles, Comparative Examples 1 and 2, which did not use wax particles containing a plant-derived wax and used wax particles not containing a plant-derived wax, and Comparative Example 5, which did not use wax particles.

20... serial printer, 220... transport unit, 230... recording unit, 231... inkjet head, 234... carriage, 235... carriage movement mechanism, F... recording medium, S1, S2... main scanning direction, T2... sub-scanning direction

Claims (8)

The composition includes a pigment, resin particles, and wax particles,
The resin particles contain at least one of a urethane resin, an acrylic resin, and a polyester resin derived from a plant,
the wax particles comprise a wax of vegetable origin;
The biomass content of the ink solids is 10 to 100%.
Inkjet ink composition. The melting point of the wax particles is 70° C. or higher.
The ink-jet ink composition of claim 1 . The pigment comprises at least one of vegetable charcoal and vegetable oil charcoal;
The ink-jet ink composition of claim 1 . The dispersant for the pigment contains lignins.
The ink-jet ink composition of claim 1 . The wax particles include at least one of carnauba wax, candelilla wax, beeswax, castor oil wax, rice wax, shellac wax, PHA wax, and beeswax;
The ink-jet ink composition of claim 1 . a mass ratio (B/A) of the content B of the wax particles to the content A of the resin particles is 0.10 to 1.00;
The ink-jet ink composition of claim 1 . Used for recording on non-absorbent or low-absorbent recording media,
The ink-jet ink composition of claim 1 . An ink deposition step of ejecting the ink-jet ink composition according to any one of claims 1 to 7 from an ink-jet head and depositing the ink on a recording medium,
Recording method.