Alkaline ink composition for digital printing and printing method using same

Abstract

The present invention relates to a printing composition comprising a binder, a solvent, and a reaction regulator. When the composition of the present invention is used, the components of the ink composition are easily agglomerated on the surface of an object, thereby improving the image quality and friction durability of the obtained object.

Description

Technical Field

[0001] This invention relates to an ink composition for digital printing and a printing method using the same. Background Technology

[0002] To print high-quality color images, inkjet printing of various contents is performed in small batches on substrates of various types and shapes, such as fabric surfaces. Inkjet printing is a widely used technology that, in response to electrical signals generated by a microprocessor, ejects a specific liquid ink composition in the form of tiny droplets from a cluster of micro-nozzles (printheads) to record text and patterns on a printing surface. In a typical inkjet printing system, in order to continuously or on-demand eject the ink composition continuously supplied and stored in the nozzle head, the electrical signals are converted into mechanical signals to record text, symbols, and patterns.

[0003] Ink compositions suitable for inkjet printing include aqueous ink compositions and non-aqueous solvent-based ink compositions. More commonly used inkjet compositions are aqueous ink compositions, which typically include water and colorants, usually comprising dye or pigment dispersions, and may further contain various additives to impart specific properties to the ink used (see Japanese Patent Publication JP2009-215506A). In this case, the quality of the final printed matter can be determined depending on the composition of the ink composition, the type of pretreatment solution, or the type of posttreatment solution used. To obtain such high-quality printed matter, the inventors have invented a composition for printing. Summary of the Invention

[0004] Technical issues The present invention aims to provide an alkaline ink composition for digital printing comprising a binder, a solvent, and a reaction modifier. Another object of the present invention is to provide a digital printing method comprising: spraying the composition onto a target object; and drying the output. Furthermore, another object of the present invention is to provide an object printed with the composition. Moreover, another object of the present invention is to provide a method for preparing an alkaline ink composition for digital printing by mixing a binder, a solvent, and a reaction modifier.

[0005] Problem-solving methods To achieve the above objectives, a composition is provided, which is an alkaline ink composition for digital printing comprising a binder, a solvent and a reaction modifier, wherein the pH of the composition is 7 to 9.

[0006] The solvent may be one or more of the following: diols: ethylene glycol, glycerol, diethylene glycol, propylene glycol, acetone, and dichloromethane.

[0007] The adhesive can be a blocked isocyanate or an acrylic-polyurethane polymer.

[0008] The reaction regulator can be one or more of sodium lactate aqueous solution, acetic acid, and butyl acetate.

[0009] The mass ratio of sodium lactate aqueous solution to acetic acid in the reaction regulator can be from 10:1 to 15:1.

[0010] The ratio of acrylic acid to polyurethane in the acrylic acid-polyurethane polymer can be from 0.5:9.5 to 1.5:8.5.

[0011] The Tg of the acrylic-polyurethane polymer can be from -50°C to -40°C.

[0012] The composition may further include one or more of surfactants, corrosion inhibitors, and antioxidants.

[0013] In one specific embodiment of the present invention, a digital printing method is provided, the method comprising the steps of spraying the composition onto a target object and drying the output. In this specific embodiment, the target object is selected from any one of the group consisting of natural fibers, synthetic fibers, and semi-synthetic fibers such as silk, cotton, wool, nylon, polyester, and viscose fiber.

[0014] In one specific embodiment of the present invention, an object printed with the said composition is provided.

[0015] In one specific embodiment of the present invention, a method is provided for preparing an alkaline ink composition for digital printing by mixing a binder, a solvent and a reaction modifier, wherein a pH adjuster is added to make the pH of the ink composition 7 to 9.

[0016] The adhesive can be a blocked isocyanate or an acrylic-polyurethane polymer.

[0017] The reaction regulator can be one or more of sodium lactate aqueous solution, acetic acid, and butyl acetate.

[0018] The mass ratio of sodium lactate aqueous solution to acetic acid in the reaction regulator can be from 10:1 to 15:1.

[0019] In one specific embodiment of the invention, the binder, as an important component of the ink, serves to fix pigments or pigments onto the printing material. The binder is a substance that strengthens the bond between the printed material and the pigments during the drying process after printing with the pretreatment liquid or ink. This has a significant impact on the durability and quality of the final printed product. The main functions of the binder are to enhance adhesion (allowing the ink to adhere well to the printing material), which is particularly important on smooth or non-absorbent surfaces, and to protect color (ensuring uniform pigment distribution on the printing material), thereby providing vibrant and uniform color, improving durability (after drying, the binder enhances the print's resistance to abrasion, fading, and chemical damage), and providing flexibility (part of the binder imparts flexibility to the print, improving its resistance to bending or other physical stresses). The type of binder is determined based on the type of material being printed for a specific purpose, the intended use of the print, and the required durability and quality standards. Furthermore, it is not limited to this; for example, for binders used in digital printing pretreatment, blocked isocyanates or acrylic-polyurethane polymers can be used.

[0020] In one specific embodiment of the invention, the reaction modifier is used to adjust the physicochemical properties of the ink composition during adhesion to the object, and to regulate the physicochemical reaction with the ink composition after adhesion to the object. This will alter the reaction environment or reaction conditions, including, for example, but not limited to, one or more of calcium chloride dihydrate, calcium nitrate tetrahydrate, calcium magnesium dihydrate, magnesium chloride, acetic acid, lactic acid, tartaric acid, aqueous sodium lactate solution, acetic acid, and butyl acetate.

[0021] In one specific embodiment of the present invention, the pH adjuster is a preparation for adjusting the pH of the reaction solution, but is not limited thereto. One or more of triethylamine (TEA), DEA, sodium dihydrogen phosphate, and aminomethylpropanediol can be used. Furthermore, ethylamine, propylamine, butylamine, diethylamine, dipropylamine, dibutylamine, triethylamine, tributylamine, monoethanolamine, diethanolamine, triethanolamine, 2-dimethylamino-2-methyl-1-propanol, 1-amino-2-propanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-amino-1-propanol, 2-dimethylamino-1-propanol, 2-diethylamino-1-propanol, 2-diethylamino-1-ethanol, 2-ethylamino-1-ethanol, 1-(dimethylamino)-2-propanol can be used. The following are some of the following: N-propanol, N-methyldiethanolamine, N-propyldiethanolamine, N-isopropyldiethanolamine, N-(2-methylpropyl)diethanolamine, N-n-butyldiethanolamine, N-tert-butylethanolamine, N-cyclohexyldiethanolamine, 2-(dimethylamino)ethanol, 2-diethylaminoethanol, 2-dipropylaminoethanol, 2-butaminoethanol, 2-tert-butylaminoethanol, 2-cycloaminoethanol, 2-amino-2-pentanol, 2-[bis(2-hydroxyethyl)amino]-2-methyl-1-propanol, 2-[bis(2-hydroxyethyl)amino]-2-propanol, N,N-bis(2-hydroxypropyl)ethanolamine, 2-amino-2-methyl-1-propanol, tris(hydroxymethyl)aminomethane, and triisopropanolamine.

[0022] In one specific embodiment of the present invention, the so-called printing pretreatment composition refers to a pretreatment liquid that is treated before the ink composition is applied, so that the components of the ink composition are more likely to condense on the surface of the object, thereby improving the image quality and friction durability of the object.

[0023] In one specific embodiment of the invention, the acrylic-polyurethane polymer is a mixture of acrylic acid and polyurethane, two different types of polymers. This mixture combines the unique properties of each polymer to form the characteristics of a new material. However, it is not limited to this; the acrylic polymer offers excellent weather resistance, color stability, transparency, and gloss, is UV resistant, does not fade, and forms a beautiful gloss on the surface. Therefore, the acrylic acid can be widely used in coatings, paints, adhesives, inks, and various plastic products. The polyurethane polymer has high flexibility, abrasion resistance, and chemical resistance, excellent impact resistance, and maintains a wide range of elasticity depending on the application environment. Therefore, it is widely used in flooring materials, footwear, seals, adhesives, and automotive parts, among other applications. In other words, the acrylic-polyurethane polymer mixture combines the advantages of both polymers to manufacture durable coating materials, adhesives, and sealants, the physical and chemical properties of which vary depending on the mixing ratio. Although the applications differ, compositions with an acrylic-polyurethane ratio of 5:95 to 15:85 are provided as printing compositions.

[0024] In a specific embodiment of the present invention, the glass transition temperature (Tg) refers to the temperature at which a polymer material transitions from a hard and brittle "glassy state" to a soft and rubbery "rubbery state." At this temperature, the physical properties of the polymer material change significantly. The glass transition temperature is an important concept for understanding the thermal properties of materials. Below this temperature, the polymer material behaves like glass—hard and brittle—while above it, the material becomes softer, more elastic, and able to absorb more energy. For example, the glass transition temperature is an important consideration when determining the operating temperature range of polymer materials such as plastics, rubbers, and adhesives. When the temperature of the environment in which the material is used is below the glass transition temperature, the material hardens; when the temperature is above the glass transition temperature, the material becomes soft. In particular, the glass transition temperature of a polymer is determined by various factors such as its structure, molecular weight, degree of cross-linking, and the presence of additives. These characteristics play an important role in the design and application of materials. Especially in compositions for printing pretreatment, the Tg of the acrylic-polyurethane polymer is not limited to this, but its range is from -50°C to -40°C.

[0025] In one specific embodiment of the present invention, the object is not limited thereto, but refers to a variety of printed objects selected from any one of the group consisting of natural fibers, synthetic fibers and semi-synthetic fibers such as silk, cotton, wool, nylon, polyester, and viscose fiber.

[0026] In one specific embodiment of the invention, the drying step is a step of drying the pretreatment composition or ink composition adhered to the object. The drying temperature is not particularly limited, and can be, for example, 60 to 150°C, 100 to 150°C, or 130 to 150°C. Furthermore, the drying time is also not particularly limited, and can be, for example, 30 seconds to 5 minutes. At this temperature, damage to the object can be suppressed, thus making it very suitable for printing on objects comprising any one of the groups selected from nylon fibers and polyester fibers. The drying step can also be used after the ink application step, the pretreatment liquid application step, or the post-treatment liquid application step. The application method of the pretreatment composition or ink composition can be one of inkjet printing, bar coater coating, roll coater coating, or spray coating.

[0027] In a specific embodiment of this invention, the so-called digital printing method refers to a technology that directly prints digitally based images from a computer or digital storage medium onto the surface of various materials. This method differs from traditional printing techniques, as it outputs images without the need for film or printing plates. It offers high efficiency in small-batch or personalized printing. Digital printing can use inkjet or laser printers to output data instantly, thereby achieving rapid production speed and high flexibility. Examples of its applications include: personalized marketing material printing (batch printing of marketing materials containing personal information such as the names or addresses of each recipient); on-demand printing (printing books or documents as needed, with less inventory pressure compared to large-batch printing); high-resolution image printing (digital printers can directly print high-resolution images onto various materials such as paper and canvas); variable data printing (VDP) (allowing the insertion of different images or text into each printed item for customized printing); and large-format printing (used for high-quality printing of large banners, posters, signs, etc.).

[0028] In a specific embodiment of the present invention, the solvent is not particularly limited, and examples include polyols, ethylene glycols, ethylene glycol monoethers, ethylene glycol diethers, ethylene glycol monoesters, ethylene glycol diesters, nitrogen-containing solvents, monohydric alcohols, glycerol, etc. As for ethylene glycols, they are not particularly limited, and examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 2-methylpentane-1,3-diol, 2-methylpentane-1,4-diol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc. As ethylene glycol monoethers, there are no particular limitations; examples include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, etc. As ethylene glycol diethers, there are no particular limitations; examples include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, etc. As ethylene glycol monoesters, there are no particular limitations; examples include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, methoxybutyl acetate, etc. As ethylene glycol diesters, there are no particular limitations; examples include ethylene glycol diacetate, ethylene glycol acetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, diethylene glycol acetate butyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, dipropylene glycol acetate butyrate, dipropylene glycol acetate propionate, etc. As a nitrogen-containing solvent, it is not particularly limited, for example, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, etc.

[0029] The type of monohydric alcohol is not particularly limited, and examples include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, isobutanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol. The total content of the organic solvent relative to the total amount of the ink composition is 50 to 30% by mass, 75 to 275% by mass, or 15 to 25% by mass. When the total content of the organic solvent is within the above range, in addition to friction durability and storage stability, there is a tendency for further improvement in the peel resistance of the printed surface or the tactile feel of the object. In particular, the pretreatment solvent is not limited to this, but can be one or more of dihydric alcohols such as ethylene glycol, glycerin, diethylene glycol, propylene glycol, acetone, and dichloromethane.

[0030] In one specific embodiment of the present invention, the resin particles are not particularly limited, and examples include acrylic resin particles, polyurethane resin particles, polyester resin particles, and polyethylene resin particles. Polyurethane resin particles may be used. By using such resin particles, in addition to improving friction durability and storage stability, it is also desirable to further improve the peel resistance of the printed surface or the tactile feel of the object. The resin particles may be used alone or in combination of two or more. The acrylic resin particles are not particularly limited, and examples include substances obtained by polymerizing (meth)acrylic acid, (meth)acrylate, or other (meth)propylene monomers, or substances obtained by copolymerizing (meth)propylene monomers with other monomers. Anionic acrylic resin particles may be used.

[0031] As polyurethane resin particles, any resin particle containing urethane bonds in its molecule is acceptable, without particular limitation. Examples include polyether-type polyurethane resins containing ether bonds in their main chain, polyester-type polyurethane resins containing ester bonds in their main chain, and polycarbonate-containing film polyurethane resins containing carbonate bonds in their main chain. Polyether-type polyurethane resins or polycarbonate-containing film polyurethane resins can be used. Furthermore, from the perspective of improving dispersion stability, anionic polyurethane resin particles containing carboxyl, sulfonyl, or hydroxyl groups can be used. As polyester resin particles, any substance obtained by reacting an acidic component with an alcoholic component is acceptable, without particular limitation. Examples of acidic components include terephthalic acid, isophthalic acid, naphthalene-dicarboxylic acid, biphenyl-2-carboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dodecanoic acid, fumaric acid, maleic acid, itaconic acid, cyclohexanedicarboxylic acid, and tetrahydrophthalic acid.

[0032] Furthermore, examples of alcohol components include ethylene glycols, which are exemplified in organic solvents. The resin particles are not particularly limited; for example, non-crosslinked resin particles and crosslinkable resin particles with crosslinking groups can be used. Non-crosslinked resin particles can be used. A crosslinking group can be a group that reacts with each other during crosslinking to form a crosslinked structure, or a group that reacts with functional groups different from the crosslinking group to form a crosslinked structure. By using non-crosslinked polyurethane resin particles, there is a tendency to further improve storage stability and the tactile feel of the resulting object. The content of resin particles relative to the total amount of the ink composition is 2.0 to 15% by mass, 3.0 to 10% by mass, or 5.0 to 8.0% by mass. When the content of resin particles is 2.0% by mass or more, there is a tendency to further improve the dry rubbing durability of the resulting object. Furthermore, when the content of resin particles is 10% by mass or less, there is a tendency to further improve the tactile feel or rubbing durability of the resulting object and the storage stability of the ink composition.

[0033] In one specific embodiment of the invention, the colorant may be additionally included in the ink composition. The colorant may be at least one of pigments and dyes. Specifically, the ink composition of this embodiment may be a pigment-containing printing ink. This composition is useful because friction durability problems are particularly prone to occur in pigment printing. Furthermore, when the colorant is a pigment, it can be used to print on various materials such as cotton, polyester, and nylon. As pigments, there are no particular limitations. Examples include carbon black (CI PigmentBlack 7) such as Noir Black, lampblack, acetylene black, and channel black; inorganic pigments such as iron oxide and titanium dioxide; and organic pigments such as quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthraquinone pyrimidine pigments, dibenzopyrene dione pigments, indanone pigments, yellow anthrone pigments, perylene pigments, pyrrolopyrrole dione pigments, pyrrole ketone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, methylimino pigments, and azo pigments. The dyes used are not particularly limited, but can include, for example: acid dyes such as CI Acid Yellow, CI Acid Red, CI Acid Blue, CI Acid Orange, CI Acid Violet, and CI Acid Black; basic dyes such as CI Basic Yellow, CI Basic Red, CI Basic Blue, CI Basic Orange, CI Basic Violet, and CI Basic Black; direct dyes such as CI Direct Yellow, CI Direct Red, CI Direct Blue, CI Direct Orange, CI Direct Violet, and CI Direct Black; reactive dyes such as CI Reactive Yellow, CI Reactive Red, CI Reactive Blue, CI Reactive Orange, CI Reactive Violet, and CI Reactive Black; and disperse dyes such as CI Disperse Yellow, CI Disperse Red, CI Disperse Blue, CI Disperse Orange, CI Disperse Violet, and CI Disperse Black. The dyes can be used alone or in combination with two or more. The pigment content relative to the total amount of the ink composition is 1.0 to 10% by mass or 2.5 to 7.5% by mass.

[0034] In one specific embodiment of the present invention, a surfactant may be additionally included in the composition. The surfactant is not particularly limited, and examples include acetylene glycol-based surfactants, fluorinated surfactants, and silicone surfactants. As an acetylene glycol-based surfactant, it is not particularly limited; for example, one or more of the following can be used: epoxide adducts of 2,4,7,9-tetramethyl-5-decyn-4,7-diol and 2,4,7,9-tetramethyl-5-decyn-4,7-diol, and epoxide adducts of 2,4-dimethyl-5-decyn-4-ol. As a fluorinated surfactant, it is not particularly limited; examples include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, and perfluoroalkyl amine oxide compounds. As a silicone surfactant, examples include polysiloxane compounds and polyether-modified organosiloxanes. The surfactant content is 0.1 to 1.0% by mass or 0.1 to 0.5% by mass relative to the total amount of the ink composition. As the polyurethane resin, any resin containing urethane bonds in its molecule is acceptable and is not particularly limited. Examples include polyether-type polyurethane resins containing ether bonds in their main chain, polyester-type polyurethane resins containing ester bonds in their main chain, and polycarbonate-containing film polyurethane resins containing carbonate bonds in their main chain. As the polyester resin, there is no particular limitation; for example, substances obtained by reacting an acidic component with an alcohol component can be used. Regarding the acidic component and the alcohol component, the aforementioned substances can be used. As the acrylic resin, it can be a resin obtained by polymerizing monomers containing at least acrylates or acrylic acid, and may also contain other monomers such as styrene. The resin content is 1.0 to 10% by mass, 1.5 to 10% by mass, or 2.5 to 7.5% by mass relative to the total amount of the post-treatment liquid.

[0035] In one specific embodiment of the present invention, the inkjet head for inkjet printing is a printhead that jets an ink composition toward an object and performs output. This printhead has: a cavity for ejecting the ink composition from a nozzle, an ejection drive unit that imparts an ejection driving force to the ink composition, and a nozzle that discharges the ink composition to the outside of the printhead. The ejection drive unit may be formed using an electromechanical conversion element such as a piezoelectric element that changes the cavity volume according to mechanical deformation, or an electrothermal conversion element that utilizes heat to generate bubbles in the ink for ejection.

[0036] Various embodiments described in this invention are illustrated with reference to the accompanying drawings. In the following description, various specific details, such as specific shapes, compositions, and processes, are described to provide a full understanding of the invention. However, specific examples may be implemented by omitting one or more of the aforementioned specific details, or by combining them with other known methods and forms. In other examples, known processes and manufacturing techniques have not been described in specific detail to avoid unnecessarily complicating or obscuring the invention. References to an embodiment throughout this specification indicate that the features, shapes, compositions, or properties described in conjunction with that embodiment are included in one or more embodiments of the invention. Therefore, the embodiments described throughout this specification do not necessarily represent the same embodiments. Furthermore, specific features, shapes, compositions, or properties may be combined in any suitable manner in one or more embodiments.

[0037] Invention Effects When the composition of the present invention is used, the components of the ink composition tend to agglomerate on the surface of the object, thereby further improving the image quality and friction durability of the obtained object.

[0038] In addition, by achieving a pH of 7 to 9 in the composition, it is possible to prevent the components using the composition (such as printheads) from being oxidized and corroded. Attached Figure Description

[0039] Figure 1 The pretreatment process and its effects are illustrated. Detailed Implementation

[0040] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention more specifically, and it will be obvious to those skilled in the art that the scope of the present invention is not limited by the spirit of the invention due to these embodiments.

[0041] The foregoing has described specific parts of the invention in detail. These specific descriptions are merely one embodiment for those skilled in the art, and therefore the scope of the invention is clearly not limited thereto. The essential scope of the invention is defined by the appended claims and their equivalents.

[0042] 1. Preparation of pretreatment agent and ink composition 1.1 Pretreatment solution Prepare the pretreatment solution as shown in the table below: Table 1 Composition and weight ratio of pretreatment agent

[0043] The components were added to a mixing tank and stirred to obtain the composition shown in Table 1 above. The mixture was then filtered through a 5 to 10 μm membrane filter to obtain the pretreatment solution for each manufacturing example. Unless otherwise specified, the component values ​​shown in Table 1 represent mass (w / w)%.

[0044] 1.2 Ink Composition Table 2 Composition and weight ratio of ink composition

[0045] The components were added to a mixing tank and stirred to obtain the composition shown in Table 2 above. The mixture was then filtered through a 5-10 μm membrane filter to obtain the ink composition. Unless otherwise specified, the component values ​​shown in Table 2 represent mass (w / w)%. The materials used in both Tables 1 and 2 are as follows: Pigment: Carbon black (manufactured by Oriental Chemical Industry Co., Ltd., product name BONJET BLACK CW-1) Surfactant: Orfin E1010 (manufactured by Nissin Chemical Industries, Ltd., an acetylene glycol-based surfactant) Corrosion inhibitor: Benzotriazole (ChemWorld 506, ChemWorld) Antioxidant: Butylated Hydroxytoluene (Lab Alley) 2. Preparation of pretreatment agent and ink composition 2.1. Adhesion and drying of pretreatment solution The pretreatment solution application is the process of applying the pretreatment solution to the object. The application area of ​​the pretreatment solution overlaps with the application area of ​​the ink composition. Specifically, the pretreatment solution is applied to the object with a pick-up rate of 80%, then heated at 100°C for 3 minutes, followed by the next ink application process.

[0046] 2.2. Adhesion and drying of the ink composition The ink adhesion process involves spraying the ink composition prepared in Example 1 onto the object using an inkjet printer PM-870C (manufactured by Seiko Epson Corporation) through the printhead, and then drying it using the same drying method as the pretreatment liquid described in 2.1.

[0047] 3. Evaluation of pretreatment agents and ink compositions 3.1. Storage Stability The printed materials prepared according to Examples 1 and 2 were placed in sample vials and sealed. The vials were then stored in a 40°C constant temperature bath for two weeks. The viscosity before and after storage was measured using a vibratory viscometer according to JIS Z8809, and the viscosity change rate after two weeks was calculated. The storage stability was evaluated according to the following criteria. A storage stability rating of A or B indicates a good result.

[0048] A: Viscosity change rate is below 3% B: Viscosity change rate exceeding 3% but less than 5% C: Viscosity change rate exceeds 5% 3.2. abrasion resistance The ink composition of Example 1 was filled into the ink cartridge of an inkjet printer PM-870C (manufactured by Seiko Epson Corporation). After filling, the nozzle inspection pattern was printed to confirm that there was no poor filling or ink accumulation on the nozzles. For the object (polyester (PES) or 100% nylon plain weave fabric) coated with the pretreatment solution of Example 1, approximately 40 ng of ink was ejected per dot, and the ink adhesion density was printed at 360 × 360 dpi. The pretreatment solution was applied to the object with a pick-up rate of 80%, and then heated at 100°C for 3 minutes to allow adhesion. Subsequently, a treatment solution of 5% by weight of polyester resin (manufactured by Toyobo Corporation, Baironar MD2000) was applied by inkjet printing, and heated at 140°C for 3 minutes to obtain the printed product. The obtained printed product was evaluated for friction durability according to ISO-105×12 standard. The evaluation criteria are as follows: a friction durability evaluation of A to C indicates a good result.

[0049] A: Wet friction exceeds level 3 B: Wet friction level 3 C: Wet friction level 2 to 3 D: Wet friction level 2 or below 3.3 Hand feel For the printed matter obtained in section 3.2, the feel of the printed area is evaluated by direct contact with the palm of the hand according to the following criteria. The evaluation is conducted by three people, and the opinion with the most support is the final result. When the three opinions differ, the median opinion is taken as the judgment result.

[0050] A: The dyed area is firm, and the feel is almost unchanged compared to the original object; it's in good condition. B: The printed area is hard, or the feel is slightly different from the original object, but it can still be used normally. C: The printed area is hard, or the feel is worse than the original object, but within acceptable limits. D: The printed area is hard, or the feel is worse than the original object, which is unacceptable. 3.4. Peel resistance The printed matter obtained in 3.2 was subjected to a load of 10 gf / cm on its surface for one week. The printed matter was then folded in half and unfolded to check for peeling of the printed surface. Peel resistance was evaluated based on the results. The evaluation criteria are as follows: A: No adhesion or peeling was observed on the printed surface. B: Although there is some adhesion on the printed surface, it has not peeled off. C: Slight peeling on the printed surface D: Peeling occurs on the printed surface. 3.5. Environmental adaptability The ink composition, which is composed of ingredients with high safety for the human body, is rated A, and its external evaluation is B.

[0051] 4. Evaluation Results The evaluation results are shown in the table below: Table 3 Evaluation results of ink composition combinations

[0052] The foregoing has described specific aspects of the invention in detail. These specific descriptions will be apparent to those skilled in the art, but are merely illustrative and the scope of the invention is not limited thereto. Therefore, the actual scope of the invention should be defined by the claims and their equivalents.

Claims

1. A composition comprising an adhesive, a solvent, and a reaction modifier for digital printing, wherein, The pH of the composition is 7 to 9.

2. The composition according to claim 1, wherein, The solvent is at least one of the following: diols: ethylene glycol, glycerol, diethylene glycol, propylene glycol, acetone, and dichloromethane.

3. The composition according to claim 1, wherein, The adhesive is a blocked isocyanate or an acrylic-polyurethane polymer.

4. The composition according to claim 1, wherein, The reaction regulator is at least one of sodium lactate aqueous solution, acetic acid, and butyl acetate.

5. The composition according to claim 4, wherein, The mass ratio of sodium lactate aqueous solution to acetic acid in the reaction regulator is 10:1 to 15:

1.

6. The composition according to claim 3, wherein, The ratio of acrylic acid to polyurethane in the acrylic acid-polyurethane polymer is from 0.5:9.5 to 1.5:8.

5.

7. The composition according to claim 6, wherein, The Tg of the acrylic-polyurethane polymer is -50°C to -40°C.

8. The composition according to claim 7, wherein, It further includes at least one of surfactants, preservatives, and antioxidants.

9. A digital printing method, wherein, include: The step of spraying the ink composition of claim 1 onto a target object to prepare an output; as well as The step of drying the output.

10. The digital printing method according to claim 9, wherein, The object to be printed is selected from one of the following groups: natural fibers such as silk, cotton, wool, nylon, polyester, and viscose fibers; synthetic fibers and semi-synthetic fibers.

11. An object printed with the composition of claim 1.

12. A method for preparing an alkaline ink composition for digital printing by mixing an adhesive, a solvent, and a reaction modifier, wherein, Add a pH adjuster to make the pH of the ink composition between 7 and 9.

13. The method according to claim 12, wherein, The adhesive is a blocked isocyanate or an acrylic-polyurethane polymer.

14. The method according to claim 12, wherein, The reaction regulator is at least one of sodium lactate aqueous solution, acetic acid, and butyl acetate.

15. The method according to claim 14, wherein, The mass ratio of sodium lactate aqueous solution to acetic acid in the reaction regulator is 10:1 to 15:1.

Images