Inkjet processing solution, inkjet printing apparatus, and inkjet printing method

Abstract

The present invention provides an inkjet processing solution that can be stably ejected from an inkjet head component, has excellent storage stability, and also exhibits excellent friction fastness when used for textile printing. [Solution] One aspect of the present disclosure relates to an inkjet processing solution containing emulsified particles containing silicone oil, a surfactant, and an aqueous medium, wherein the content of the silicone oil is 5% by mass or more and 15% by mass or less of the total processing solution, and the surfactant contains a first surfactant containing an alkyl group having 12 to 14 carbon atoms and a second surfactant containing an alkyl group having 16 to 18 carbon atoms.

Description

[Technical Field]

[0001] This disclosure relates to an inkjet processing solution, and further to an ink set printing apparatus and an inkjet printing method using the same. [Background technology]

[0002] In inkjet recording methods, it is known that a processing solution is applied after ink application to suppress deformation of the recording medium and improve image fixation.

[0003] For example, Patent Document 1 discloses that feathering, bleeding, and paper deformation can be suppressed by using a processing solution containing a surfactant. According to the same document, it is also reported that it is particularly preferable to use a processing solution containing two types of surfactants.

[0004] Furthermore, it has been reported that by including surfactants in the inkjet recording solution, ink drying properties, optical density, feathering, and image fixation can be achieved simultaneously (Patent Document 2). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-16556 [Patent Document 2] Japanese Patent Publication No. 2001-226616 [Overview of the project]

[0006] An inkjet processing solution according to one aspect of the present disclosure is an inkjet processing solution comprising an emulsion particle containing silicone oil, a surfactant, and an aqueous medium, wherein the content of the silicone oil is 5% by mass or more and 15% by mass or less of the total processing solution, and the surfactant comprises a first surfactant containing an alkyl group having 12 to 14 carbon atoms and a second surfactant containing an alkyl group having 16 to 18 carbon atoms. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing one embodiment of an inkjet textile printing apparatus that uses the inkjet processing solution of this embodiment. [Modes for carrying out the invention]

[0008] The processing solution described in Patent Document 1 contains a surfactant, but its purpose is to improve image quality and suppress paper deformation, and no consideration has been given to the storage stability of the processing solution. Furthermore, the invention described in Patent Document 2 concerns the inkjet recording solution itself, not the processing solution, and this document also does not describe how to improve the storage stability of the inkjet recording solution.

[0009] On the other hand, in inkjet printing technology, a post-treatment solution containing silicone oil is sometimes used to ensure the friction fastness of the printed material. Our research has shown that in post-treatment solutions containing silicone oil ejected by inkjet, it is necessary to control the particle size of the silicone oil to ensure ejection stability. We have also found that this can be adjusted by adding a surfactant to the post-treatment solution.

[0010] However, it has been found that when a post-treatment liquid containing silicone oil and a surfactant is stored for a long time, the surfactant may detach from the surface of the silicone oil, making it difficult to maintain the desired particle size. If the particle size of the silicone oil cannot be maintained within an appropriate range, there is a problem that it is difficult to ensure ejection stability.

[0011] Also, both of the technologies described in Patent Documents 1 and 2 mentioned above mainly relate to inkjet image forming methods for printing on paper media such as plain paper and liquid low-absorbency recording media such as film sheets, and aim to form good images with suppressed bleeding and the like, and are not so much assumed to be used for printing on fabrics and the like. However, in the case of inkjet recording used for printing, in addition to image quality and the like, printing-specific characteristics such as rubbing fastness are also required.

[0012] Hereinafter, embodiments according to the present disclosure will be specifically described, but the present disclosure is not limited thereto. In this specification, the measured value of the volume median diameter (D

[0013] , , , ,

[0012] , 50 , 50 , ) is the median diameter measured using a laser diffraction / scattering type particle size distribution measuring device ("LA-950" manufactured by Horiba, Ltd.) unless otherwise specified. Hereinafter, the volume median diameter may be referred to as "D 50 ". The "main component" of a material means the component most contained in the material on a mass basis unless otherwise specified. "Specific gravity" means the specific gravity at 25°C unless otherwise specified. Acrylic and methacrylic may be collectively referred to as "(meth)acrylic" in some cases. Each component described in this specification may be used alone or in combination of two or more.

[0013] [Treatment Liquid for Inkjet] An inkjet treatment liquid according to an embodiment of the present disclosure (hereinafter, may be simply referred to as "treatment liquid") is an inkjet treatment liquid containing emulsified particles containing silicone oil, a surfactant, and an aqueous medium, wherein the content of the silicone oil is 5% by mass or more and 15% by mass or less with respect to the entire treatment liquid, and the surfactant contains a first surfactant containing an alkyl group having 12 to 14 carbon atoms and a second surfactant containing an alkyl group having 16 to 18 carbon atoms.

[0014] With the above configuration, the treatment liquid of this embodiment is stably discharged from the inkjet head member and has excellent storage stability. That is, according to the present disclosure, an inkjet treatment liquid that can be stably discharged from an inkjet head member and has excellent storage stability can be provided. Further, when the inkjet treatment liquid of the present disclosure is used for printing, there is an advantage that the rubbing fastness is also excellent.

[0015] The treatment liquid of this embodiment is preferably used, for example, in an inkjet printing apparatus and an inkjet printing method described later. The treatment liquid of this embodiment is a treatment liquid for post-treatment. That is, after an image is formed in an image forming region to be printed with ink, the image forming region is post-treated with the treatment liquid of this embodiment.

[0016] When the treatment liquid of this embodiment is used for printing, in addition to the above advantages, there is an advantage that the rubbing fastness can be improved.

[0017] Hereinafter, the configuration of the inkjet treatment liquid according to this embodiment will be described. The treatment liquid according to this embodiment contains emulsified particles containing silicone oil, a surfactant, and an aqueous medium. That is, the treatment liquid of this embodiment is an emulsion in which emulsified particles are dispersed in an aqueous medium, and more specifically, an oil-in-water (O / W) type emulsion.

[0018] (Emulsified Particles) The emulsified particles contained in the processing solution contain silicone oil. The silicone oil contained in the emulsified particles is not particularly limited, but it is preferable that it contains at least unmodified silicone oil. By including unmodified silicone oil, it is possible to produce printed materials with superior friction fastness, especially wet friction fastness, when used for textile printing.

[0019] Examples of non-modified silicone oils include dimethylpolysiloxane, methylphenyl silicone oil, and methylhydrogen silicone oil. Among these, the use of dimethylpolysiloxane is preferred.

[0020] Furthermore, the silicone oil may be a silicone oil other than a non-modified silicone oil, or it may contain both a non-modified silicone oil and other silicone oils. In this case, one emulsion particle may contain both a non-modified silicone oil and other silicone oils. Alternatively, the emulsion solution may contain two or more types of emulsion particles, for example, a first emulsion particle may contain a non-modified silicone oil and a second emulsion particle may contain another silicone oil. Examples of other silicone oils include ionic group-containing silicone oils.

[0021] When the processing solution of this embodiment is used for textile printing, the viscosity of the silicone oil is 500 mm. 2 / s (i.e., mm 2 Preferably, the viscosity of the silicone oil is 500 mm² / second or higher. 2 When the friction rate is 500 mm or higher, the silicone oil is less likely to detach from the printed material due to friction, and it is believed that printed materials with superior dry friction fastness and wet friction fastness can be produced. Furthermore, as already mentioned, the processing liquid according to this embodiment has excellent discharge properties from the processing head of an inkjet printing apparatus. When the processing liquid is discharged from the processing head, the amount of processing liquid used is reduced compared to when the printed material is immersed in the processing liquid, so 500 mm 2Even when a silicone oil with a high viscosity of / s or more is used as the treatment liquid, it is difficult to cause roughness on the printing target, and a decrease in the touch feeling of the printed matter is further suppressed.

[0022] The upper limit of the viscosity of the silicone oil is not particularly limited. The viscosity of the silicone oil is, for example, 100000 mm 2 / s or less, preferably 6000 mm 2 / s or less. The viscosity of the silicone oil is, for example, 500 mm 2 / s, 700 mm 2 / s, 900 mm 2 / s, 1000 mm 2 / s, 1100 mm 2 / s, 1200 mm 2 / s, 1500 mm 2 / s, 1700 mm 2 / s, 1800 mm 2 / s, 2000 mm 2 / s, 3000 mm 2 / s, and 5700 mm 2 / s, and may be within the range of two values selected from the group consisting of 6000 mm 2 / s.

[0023] In the present embodiment, the viscosity of the silicone oil means the kinematic viscosity at 25°C. When the emulsion particles contain two or more types of silicone oils (for example, an ionic group-containing silicone oil and other silicone oils), the viscosity of the silicone oil means the viscosity of a mixture of two or more types of silicone oils.

[0024] The viscosity of the silicone oil is a value measured in accordance with the method described in JIS (Japanese Industrial Standards) Z8803:2011 (Method for Measuring Viscosity of Liquids). Specifically, for example, the silicone oil can be separated from the treatment liquid by extracting, washing, and drying the silicone oil from the treatment liquid with toluene, and then measuring the viscosity of the silicone oil.

[0025] The silicone oil content in the processing solution of this implementation is 5% by mass or more and 15% by mass or less. Having a silicone oil content within this range allows for more stable discharge of the processing solution and improves friction fastness when used for textile printing. Preferably, the silicone oil content in the processing solution is 7% by mass or more. Also, preferably, the silicone oil content in the processing solution is 13% by mass or less.

[0026] In this embodiment, the silicone oil content in the processing solution refers to the percentage of the mass of silicone oil relative to the total mass of the processing solution. If the emulsified particles contain two or more types of silicone oil (for example, unmodified silicone oil and other silicone oils), the silicone oil content refers to the percentage of the total mass of the two or more types of silicone oil relative to the mass of the processing solution.

[0027] Furthermore, the emulsified particles may contain components other than silicone oil. However, from the viewpoint of producing a printed material with excellent friction fastness, it is preferable that the emulsified particles contain only silicone oil.

[0028] The average particle size of the emulsion particles (dispersed particle size in an aqueous medium) is preferably between 100 nm and 250 nm. Having the average particle size of the emulsion particles within this range provides the advantage that the processing solution of this embodiment exhibits superior ejection from the processing head of an inkjet device. Furthermore, it allows for more reliable abrasion fastness when used for textile printing. A more preferable range for the average particle size of the emulsion particles is between 120 nm and 220 nm, and even more preferably between 150 nm and 200 nm. Alternatively, the average particle size of the emulsion particles may be within the range of two values ​​selected from the group consisting of, for example, 100 nm, 120 nm, 135 nm, 150 nm, 155 nm, 160 nm, 180 nm, 200 nm, 210 nm, 220 nm, and 250 nm.

[0029] In this embodiment, the average particle diameter refers to the harmonic mean particle diameter (also called the cumulant mean particle diameter) calculated based on the scattered light intensity criterion using the cumulant method. In other words, the average particle diameter of the emulsified particles is a value measured in accordance with the method described in ISO 13321:1996 (Particle size analysis - Photon correlation spectroscopy).

[0030] Furthermore, in this embodiment, when the inkjet processing solution is stored at 60°C for 30 days, the average particle size X of the emulsified particles in the processing solution before storage and the average particle size Y of the emulsified particles in the processing solution after storage are given by the following formula: 1.0 ≤ Y / X ≤ 1.05 It is preferable that the following conditions be met.

[0031] Since the average particle diameter X and average particle diameter Y satisfy the above formula, the average particle diameter of the emulsified particles does not change significantly even when the processed solution is stored for a long period of time. Therefore, it is considered that a processed solution with excellent storage stability can be obtained more reliably.

[0032] It is even more preferable that the above formula is 1.0 ≤ Y / X ≤ 1.03.

[0033] In this specification, "processing solution before storage" preferably refers to the processing solution immediately after preparation, but it may also refer to the processing solution after a predetermined period of storage, unless it has been stored in a particularly harsh environment.

[0034] (Surfactants) The processing solution of this embodiment contains, as surfactants, a first surfactant containing an alkyl group having 12 to 14 carbon atoms, and a second surfactant containing an alkyl group having 16 to 18 carbon atoms. By including such surfactants, the processing solution can ensure discharge stability. This is because the inclusion of two types of surfactants with carbon number ranges in the processing solution suppresses the fusion of the emulsion particles dispersed in the processing solution, thereby preventing the emulsion particles from becoming unnecessarily large. In other words, by including the surfactants, the processing solution of this embodiment can maintain the size (average particle diameter) of the emulsion particles dispersed in the processing solution within an appropriate range.

[0035] If only one of the two surfactants described above is included, the surfactant will detach from the silicone oil surface that forms the emulsion particles, making it impossible to maintain the average particle size of the emulsion particles.

[0036] Furthermore, if the alkyl group of the first surfactant has 11 or fewer carbon atoms, the surfactant is more likely to be released from the silicone oil at relatively high temperatures (around 60°C). Therefore, to ensure dispersion stability in the aforementioned temperature range, it is necessary to increase the amount of the first surfactant. However, increasing the amount of the first surfactant causes thixotropy, so the alkyl group of the first surfactant has 12 to 14 carbon atoms. In a preferred embodiment, the alkyl group of the first surfactant has 12 and / or 14 carbon atoms.

[0037] On the other hand, if the number of carbon atoms in the alkyl group of the second surfactant is 19 or more, the amount of free components that do not adhere to (are not incorporated into) the silicone oil increases, resulting in the viscosity of the treatment solution becoming too high or thixotropy occurring. Therefore, the number of carbon atoms in the alkyl group of the second surfactant should be 16 to 18. In a preferred embodiment, the number of carbon atoms in the alkyl group of the second surfactant is 16 and / or 18.

[0038] The first surfactant can be any surfactant having an alkyl group with 12 to 14 carbon atoms, without any particular limitations. Preferably, polyoxyethylene alkyl ethers can be used. More specifically, for example, polyoxyethylene lauryl ether (C12), polyoxyethylene tridecyl ether (C13), polyoxyethylene myristyl ether (C14), etc., can be used. Furthermore, the first surfactant may contain two or more compounds having alkyl groups with different numbers of carbon atoms.

[0039] Furthermore, the second surfactant can be any surfactant having an alkyl group with 16 to 18 carbon atoms, without any particular limitations. Preferably, polyoxyethylene alkyl ethers can be used. More specifically, for example, polyoxyethylene cetyl ether (C16), polyoxyethylene stearyl ether (C18), etc., can be used. Moreover, the second surfactant may contain two or more compounds having alkyl groups with different numbers of carbon atoms.

[0040] Furthermore, surfactants other than those mentioned above may be added to the processing solution of this embodiment, as long as they do not hinder the effects of the present disclosure.

[0041] In the processing solution of this embodiment, it is preferable that the content of the second surfactant is less than the content of the first surfactant. This is thought to result in a processing solution with superior discharge properties and storage stability. Furthermore, it is thought that a printed product with superior friction fastness, particularly wet friction fastness, can be obtained when used for textile printing.

[0042] Furthermore, it is preferable that the content of the first surfactant and the content of the second surfactant satisfy the following formula: Content of the second surfactant / (Content of the first surfactant + Content of the second surfactant) = 0.15 to 0.25 (mass%). It is believed that if the content of the second surfactant is within the above range relative to the total content of the first surfactant and the second surfactant, dispensing properties and storage stability can be more reliably obtained. This is because if the content of the second surfactant is too high, thixotropy may occur, which may lead to deterioration of dispensing properties and storage stability.

[0043] In the processing solution of this embodiment, the total content of the first surfactant and the second surfactant is preferably 0.5% by mass or more and 4.0% by mass or less of the total processing solution. In particular, in order to obtain better storage stability and discharge properties, the lower limit of the total content relative to the total processing solution is preferably 1.0% by mass or more, and more preferably 1.5% by mass or more. Furthermore, the upper limit of the total content is preferably 2.5% by mass or less, and more preferably 2.0% by mass or less.

[0044] Furthermore, in the processing solution of this embodiment, the total content of the first surfactant and the second surfactant is preferably 9.0% by mass or more and 40.0% by mass or less relative to the content of silicone oil. In particular, from the viewpoint of obtaining better discharge properties and friction fastness when used for textile printing, the lower limit of the total content of the surfactant relative to the content of silicone oil is preferably 10.0% by mass or more, and more preferably 15% by mass or more. Furthermore, the upper limit of the total content is preferably 35.0% by mass or less.

[0045] (aqueous medium) The aqueous medium contained in the processing solution of this embodiment is a medium mainly composed of water. The aqueous medium may function as a solvent or as a dispersion medium. Specific examples of the aqueous medium include water or a mixture of water and a polar solvent. Examples of polar solvents contained in the aqueous medium include methanol, ethanol, isopropyl alcohol, butanol, and methyl ethyl ketone. The water content in the aqueous medium is preferably 90% by mass or more, and particularly preferably 100% by mass. The content of the aqueous medium is preferably 50% by mass or more and 90% by mass or less, and more preferably 55% by mass or more and 70% by mass or less, relative to the mass of the processing solution.

[0046] (Other ingredients) The processing solution of this embodiment may further contain polyols as needed. The viscosity of the processing solution is suitably adjusted by the inclusion of polyols. Diols or triols are preferred as polyols. Examples of diols include glycol compounds, more specifically, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol. An example of a triol is glycerin. When the processing solution contains polyols, the polyol content is preferably 10% to 40% by mass, and more preferably 15% to 35% by mass, relative to the mass of the processing solution.

[0047] Furthermore, the processing solution may contain other additives, as long as they do not hinder the effects of the present disclosure. Examples of additives include dispersants, dissolution stabilizers, drying inhibitors, antioxidants, viscosity modifiers, pH adjusters, and fungicides.

[0048] (Method of manufacturing the treatment solution) The method for producing the treatment solution in this embodiment is not particularly limited, but one example will be described. For example, a homogenizer is used to mix and emulsify silicone oil, a surfactant, an aqueous medium, and components added as needed (e.g., polyols). In this way, emulsion particles containing silicone oil can be dispersed in the aqueous medium to obtain the treatment solution.

[0049] (Application) The processing solution of this embodiment is particularly suitable for use in inkjet printing. When using pigment inks that enable printing on many types of fabrics, it is necessary to fix the pigment to the fabric surface. If the pigment cannot be fixed to the fabric surface, there is a problem of poor friction fastness.

[0050] The aforementioned problems can be resolved by using the processing solution of this embodiment. In other words, the processing solution of this embodiment can improve the fastness to wet and dry friction in the production of printed materials, making it extremely useful for industrial applications.

[0051] [Inkjet Printing Machine] Next, an inkjet printing apparatus according to this embodiment will be described.

[0052] The inkjet printing apparatus 10 according to this embodiment comprises at least a recording head 1 for ejecting ink onto the image-forming area of ​​an object to be printed, a processing head 2 for ejecting processing liquid onto at least the image-forming area of ​​the object to be printed, and a mounting table 3 for transporting the object to be printed, wherein the processing liquid ejected from the processing head is the inkjet processing liquid described above. For ease of understanding, Figure 1 schematically shows each component, and the size, number, etc. of each component shown may be changed as appropriate. Figure 1 is a side view showing the main parts of an inkjet printing apparatus 10, which is an example of an inkjet printing apparatus according to this embodiment. The inkjet printing apparatus 10 shown in Figure 1 is a flatbed type inkjet printing apparatus.

[0053] The inkjet printing apparatus 10 according to this embodiment processes the object to be printed P using the processing solution of this embodiment described above. Because the processing solution according to this embodiment is used, the inkjet printing apparatus 10 can produce printed materials with excellent wet abrasion fastness and dry abrasion fastness.

[0054] The inkjet printing apparatus 10 shown in Figure 1 comprises a recording head 1, a processing head 2, and a mounting table 3. The recording head 1 has a first recording head 1a, a second recording head 1b, a third recording head 1c, and a fourth recording head 1d.

[0055] The recording head 1 ejects ink onto the image forming area of ​​the print target P. The first recording head 1a, second recording head 1b, third recording head 1c, and fourth recording head 1d of the recording head 1 each eject ink of a different color (for example, yellow ink, magenta ink, cyan ink, and black ink). The recording head 1 is not particularly limited, but examples include a piezo type head and a thermal inkjet type head.

[0056] The processing head 2 discharges a processing liquid for post-processing onto at least the image forming area of ​​the printing target P. The processing liquid is the processing liquid according to the first embodiment. The processing head 2 is not particularly limited, but examples include a piezo type head and a thermal inkjet type head. The inkjet printing apparatus 10 of this embodiment may further include one or more processing liquid tanks (not shown) for containing the processing liquid, in which case the processing liquid is supplied to the processing head 2 from the processing liquid tanks.

[0057] The printing target P is placed on the mounting table 3. A recording head 1 and a processing head 2 are positioned above the mounting table 3 so that ink and processing liquid can be dispensed onto the printing target P. Driven by a motor (not shown), the mounting table 3 moves horizontally in the direction from the recording head 1 to the processing head 2 (for example, to the left in Figure 1). As the mounting table 3 moves horizontally, the printing target P on the mounting table 3 is transported.

[0058] The fabric to be printed P may be woven or knitted. Examples of fabrics to be printed P include cotton, silk, linen, acetate, rayon, nylon, polyurethane, and polyester.

[0059] In the preparation of a printed material, first, the mounting platform 3 on which the material to be printed P is placed moves horizontally, and the material to be printed P is transported to a position facing the recording head 1. Ink is ejected from the recording head 1 into the image forming area of ​​the material to be printed P. In this way, an image is formed on the image forming area of ​​the material to be printed P by the ink. After the ink is ejected, the mounting platform 3 on which the material to be printed P is placed moves horizontally again, and the material to be printed P is transported to a position facing the processing head 2. Processing liquid is ejected from the processing head 2 into at least the image forming area of ​​the material to be printed P. In this way, a processing film is formed on the image formed on the image forming area of ​​the material to be printed P by the processing liquid.

[0060] The processing head 2 may discharge the processing liquid only to the image forming area of ​​the print target P, to a wider area than the image forming area of ​​the print target P, or to discharge the processing liquid over the entire surface of the print target P. In order to reduce the amount of processing liquid used and suppress the deterioration of the tactile feel of the printed material, it is preferable for the processing head 2 to discharge the processing liquid only to the image forming area of ​​the print target P, and more preferably to discharge the processing liquid only to the area within the image forming area where ink has been discharged by the recording head 1. Since the processing head 2 can accurately control the position in which the processing liquid is discharged, it is possible to discharge the processing liquid only to the area where ink has been discharged. In order to accurately control the position in which the processing liquid is discharged, it is preferable that the distance between the processing head 2 and the print target P is 1 mm or more and 5 mm or less. Furthermore, in order to efficiently carry out post-processing with the processing liquid, it is preferable that only the processing liquid is discharged from the processing head 2.

[0061] After the processing liquid is discharged from the processing head 2 to the printing target P, the mounting table 3 on which the printing target P is placed moves horizontally further to transport the printing target P to a position facing the heating unit (not shown). The heating unit heats the printing target P, drying the ink and processing liquid. The heating temperature is, for example, between 120°C and 180°C. The heating time is, for example, between 1 minute and 10 minutes. Heating causes volatile components contained in the ink and processing liquid to evaporate, promoting the fixation of the ink and processing liquid to the printing target P. As a result, a printed product is produced in which an image is formed by the ink and the printing target P is processed by the processing liquid.

[0062] The inkjet printing apparatus 10 according to the second embodiment has been described above. However, the inkjet printing apparatus of this disclosure is not limited to the inkjet printing apparatus 10 described above, and can be modified as shown in the following modifications, for example.

[0063] Regarding the first modification, the inkjet printing apparatus 10 may be equipped with a spray for dispensing the processing liquid instead of a processing head 2 for ejecting the processing liquid.

[0064] Regarding the second modification, the treatment with the treatment solution may be carried out by immersing the object to be printed P in a tank in which the treatment solution is stored. When immersion is performed, the amount of treatment solution discharged, as described later in the third embodiment, corresponds to the amount of treatment solution applied.

[0065] Regarding the third modification, in the inkjet printing apparatus 10, the mounting table 3 moves horizontally, but the recording head 1 and processing head 2 may move horizontally while the mounting table 3 is fixed.

[0066] Regarding the fourth modification, the mounting table 3 may move horizontally in the transport direction of the object to be printed P, or the recording head 1 and processing head 2 may move horizontally, and the recording head 1 and processing head 2 may also move horizontally in a direction perpendicular to the transport direction of the object to be printed P.

[0067] Regarding the fifth modified example, the number of recording heads 1 may be 1 to 3 or 5 or more.

[0068] Regarding the sixth modification, the inkjet printing apparatus may not be a flatbed type. As long as it is equipped with a recording head 1 and a processing head 2, the effects of using the processing liquid according to the first embodiment can be obtained regardless of the type of inkjet printing apparatus.

[0069] [Inkjet Printing Method] Next, the inkjet printing method according to this embodiment will be described with reference to Figure 1. The inkjet printing method of this embodiment is a method of forming an image in the image-forming area of ​​the printing target P using the processing liquid described above. Alternatively, the inkjet printing method of this embodiment is also a method of forming an image in the image-forming area of ​​the printing target P using the inkjet printing apparatus 10 described above. Because the inkjet printing method of this embodiment uses the processing liquid described above, it is possible to produce printed materials with excellent friction fastness. Furthermore, since the processing liquid of this embodiment has excellent discharge properties from the processing head, these effects can be reliably demonstrated in the inkjet printing method.

[0070] The inkjet printing method of this embodiment includes an ink ejection step and a processing step. In the ink ejection step, ink is ejected from the recording head 1 onto the image forming area of ​​the printing target P. In the processing step, a processing liquid is ejected from the processing head 2 onto at least the image forming area of ​​the printing target P. The processing liquid is the processing liquid according to the first embodiment. The processing step is preferably a post-processing step performed after the ink ejection step. The inkjet printing method may further include a heating step as needed.

[0071] In the ink ejection process, the amount of ink ejected to the printing target P is, for example, 5 g / m². 2 More than 40g / m 2 The following applies:

[0072] In the processing step, the amount of processing solution discharged to the object to be printed P is, for example, 10 g / m². 2 More than 120g / m 2The following applies (including when applied by coating): To particularly improve dry friction fastness, the discharge rate of the treatment solution is 15 g / m². 2 More than 30g / m 2 Preferably, the following conditions apply: In order to particularly improve wet friction fastness in addition to dry friction fastness, the discharge rate of the treatment solution is 17 g / m². 2 More than 25g / m 2 The following is more preferable:

[0073] [ink] The ink used in inkjet recording together with the processing solution of this embodiment, and the ink used in the printing apparatus or printing method, are not particularly limited, but for example, an ink containing a pigment and an aqueous medium can be used. The ink may further contain, if necessary, at least one selected from the group consisting of surfactants, polyols, and binder resin particles.

[0074] For example, dispersible pigments that exist dispersed in an aqueous medium can be used as the pigment. From the viewpoint of obtaining an ink with excellent image density, hue, and color stability, the D50 of the pigment is preferably 30 nm to 250 nm, and more preferably 70 nm to 160 nm.

[0075] Examples of pigments include yellow pigments, orange pigments, red pigments, blue pigments, purple pigments, and black pigments. Examples of yellow pigments include CI Pigment Yellow (74, 93, 95, 109, 110, 120, 128, 138, 139, 151, 154, 155, 173, 180, 185, and 193). Examples of orange pigments include CI Pigment Orange (34, 36, 43, 61, 63, and 71). Examples of red pigments include CI Pigment Red (122 and 202). Examples of blue pigments include CI Pigment Blue (15, more specifically 15:3). Examples of purple pigments include CI Pigment Violet (19, 23, and 33). Examples of black pigments include CI Pigment Black (7).

[0076] The pigment content is preferably 1% to 12% by weight, and more preferably 1% to 7% by weight, relative to the total weight of the ink. A pigment content of 1% by weight or more improves the image density of the resulting recording. Furthermore, a pigment content of 12% by weight or less yields an ink with high fluidity.

[0077] In particular, the ink of this embodiment preferably contains an anionic pigment. As a result, the cationic polymer contained in the processing solution and the anionic pigment react electrically and aggregate on the surface of the recording object, thereby suppressing the penetration of the binder resin (described later) contained in the ink into the recording medium. This is especially important when the recording medium is fabric, as it prevents the binder resin from penetrating into the gaps between fibers and binding the fibers together. This enhances the texture (feel, etc.) of the fabric to be printed.

[0078] As for anionic pigments, anionic pigments having anionic groups such as carboxyl groups, sulfonic acid groups, phosphate groups, phosphonic acid groups, phenylsulfonic acid groups, and phenylcarboxyl groups are more preferred.

[0079] The aqueous medium contained in the ink of this embodiment is a medium mainly composed of water. The aqueous medium may function as a solvent or as a dispersion medium. Specific examples of the aqueous medium include water or a mixture of water and a polar solvent. Examples of polar solvents contained in the aqueous medium include methanol, ethanol, isopropyl alcohol, butanol, and methyl ethyl ketone. The water content in the aqueous medium is preferably 90% by weight or more, and particularly preferably 100% by weight. The content of the aqueous medium is preferably 5% by weight or more and 70% by weight or less, and more preferably 40% by weight or more and 60% by weight or less, relative to the total weight of the ink.

[0080] Furthermore, the inclusion of a surfactant in the ink improves the wettability of the ink to the recording object. Examples of surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. The surfactant contained in the ink is preferably a nonionic surfactant. The nonionic surfactant is preferably a surfactant having an acetylene glycol structure, and more preferably an acetylenediol ethylene oxide adduct. The HLB value of the surfactant is preferably 3 to 20, more preferably 6 to 16, and even more preferably 7 to 10. The HLB value of the surfactant can be calculated, for example, by the Griffin method using the formula "HLB value = 20 × (sum of formula weights of hydrophilic parts) / molecular weight". In order to improve image density while suppressing image offset, the surfactant content is preferably 0.1% to 5.0% by weight, and more preferably 0.5% to 2.0% by weight, relative to the total weight of the ink.

[0081] Furthermore, the viscosity of the ink can be suitably adjusted by including a polyol in the ink. Diols or triols are preferred as the polyols included in the ink. Examples of diols include glycol compounds, more specifically, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol. An example of a triol is glycerin.

[0082] When the ink contains polyol, the polyol content is preferably 5% to 60% by weight, and more preferably 20% to 50% by weight, relative to the total weight of the ink, in order to suitably adjust the viscosity of the ink.

[0083] The binder resin particles contained in the ink of this embodiment exist in a dispersed state in an aqueous medium. The binder resin particles function as a binder that binds the printing target and the pigment. Therefore, by including binder resin particles in the ink, it is possible to obtain a printed material with excellent pigment fixation.

[0084] Examples of resins contained in the binder resin particles include urethane resin, (meth)acrylic resin, styrene-(meth)acrylic resin, styrene-maleic acid copolymer, vinylnaphthalene-(meth)acrylic acid copolymer, and vinylnaphthalene-maleic acid copolymer. Urethane resin is preferred as the resin contained in the binder resin particles. The content of urethane resin in the binder resin particles is preferably 80% by weight or more, and more preferably 100% by weight.

[0085] The binder resin content is preferably 1% to 20% by weight, and more preferably 2% to 10% by weight, relative to the total weight of the ink. When the binder resin particle content is 1% or more by weight, a recording surface with excellent pigment fixation can be obtained. On the other hand, when the binder resin particle content is 20% or less by weight, the ink can be stably ejected onto the recording surface.

[0086] Furthermore, the ink of this embodiment may optionally contain known additives (more specifically, dissolution stabilizers, drying inhibitors, antioxidants, viscosity modifiers, pH adjusters, and antifungal agents, etc.).

[0087] The ink used in this embodiment is manufactured, for example, by mixing a pigment, an aqueous medium, and optionally added components (e.g., surfactants, polyols, and binder resin particles) using a stirrer. The mixing time is, for example, 1 minute or more and 30 minutes or less. [Examples]

[0088] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited in any way by these examples.

[0089] In the examples described below, the average particle size of each emulsified particle was measured using the method described below.

[0090] <Method for measuring the average particle size of emulsified particles> The average particle size of the emulsified particles was measured using a laser diffraction particle size distribution analyzer (Malvern's "Zetasizer Nano ZS") in accordance with the method described in ISO 13321:1996 (Particle size analysis - Photon correlation spectroscopy). For the measurement of the average particle size of the emulsified particles, a sample prepared by diluting the treatment solution 1000 times with water was used.

[0091] Furthermore, the first and second surfactants used in this embodiment are as follows. (First surfactant) • Surfactant 1 (polyoxyethylene lauryl ether, alkyl group: C12) • Surfactant 2 (polyoxyethylene tridecyl ether, alkyl group: C13) • Surfactant 3 (polyoxyethylene myristyl ether, alkyl group: C14) (Second surfactant) • Surfactant 4 (polyoxyethylene cetyl ether, alkyl group: C16) • Surfactant 5 (polyoxyethylene stearyl ether, alkyl group: C18).

[0092] (Example 1) 5g of unmodified silicone oil (Shin-Etsu Chemical Co., Ltd. "KF96-3000cs", dimethylpolysiloxane, viscosity: 3,000mm) 263.37 g of deionized water (1 / s, specific gravity: 0.97), 30 g of propylene glycol, and 1.3 g of a first surfactant (surfactant 1: C=12) and 0.33 g of a second surfactant (surfactant 4: C=16) were placed in a beaker. The contents of the beaker were stirred for 15 minutes at a rotation speed of 10,000 rpm using a homogenizer (IKA "Ultra-Turrax T25"), and then allowed to stand for 30 minutes. Next, the contents of the beaker were filtered through a 120-mesh stainless steel filter to obtain treatment solution 1. Emulsified particles containing unmodified silicone oil were dispersed in treatment solution 1. The average particle size (X) of the emulsion particles was 115 nm.

[0093] (Example 2) 10g of unmodified silicone oil (Shin-Etsu Chemical Co., Ltd. "KF96-3000cs", dimethylpolysiloxane, viscosity: 3,000mm) 2 58.37 g of deionized water (60°F, specific gravity: 0.97), 30 g of propylene glycol, and 1.3 g of a primary surfactant (surfactant 1: C=12) and 0.33 g of a secondary surfactant (surfactant 4: C=16) were placed in a beaker. The contents of the beaker were stirred for 15 minutes at a rotation speed of 10,000 rpm using a homogenizer (IKA "Ultra-Turrax T25"), and then allowed to stand for 30 minutes. Next, the contents of the beaker were filtered through a 120-mesh stainless steel filter to obtain treatment solution 1. Treatment solution 2 contained dispersed emulsion particles containing unmodified silicone oil. The average particle size (X) of the emulsion particles was 138 nm.

[0094] (Examples 3-14 and Comparative Examples 1-3) Except for changing the amounts (by weight) of the unmodified silicone oil, the first surfactant, and the second surfactant as shown in Table 1, and adjusting the amount of deionized water to 100 g when combined with the above-mentioned components and 30 g of propylene glycol (fixed), the treatment solutions (treatment solutions 3 to 17) for Examples 3 to 14 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1. Each of the obtained treatment solutions contained dispersed emulsion particles with unmodified silicone oil. The average particle size (X) of the emulsion particles in each treatment solution is shown in Table 2 below.

[0095] [Table 1]

[0096] [Evaluation Method] <Storage stability> 400g each of the treatment solutions 1-17 obtained in each example and comparative example were placed in a 500mL plastic container and stored in a 60°C oven for 30 days. After 30 days, the plastic containers were removed from the oven, and after the treatment solutions had cooled to room temperature, the average particle size (Y) of the emulsified particles in each treatment solution was measured, and the discharge performance test described later was performed.

[0097] <Dischargeability> The discharge performance of the processing solution was evaluated using a discharge evaluation device (Kyocera Corporation, "KJ4B") that allows for confirmation of the discharge of each drop of processing solution from the nozzle via camera footage. This discharge performance was evaluated for both the processing solution before storage (immediately after preparation) and the processing solution after 30 days of storage, as described in the section on storage stability above.

[0098] The conditions for the discharge evaluation machine were set as follows: Conditions for the discharge evaluation machine: Head temperature: 32℃ Discharge volume of processing liquid from the head: 10g / m 2 Driving frequency: 30kHz

[0099] The specific method for evaluating the discharge performance is as follows: First, using the discharge evaluation machine, the camera position was adjusted so that three nozzles were visible in one field of view. Next, the discharge of the processing liquid was started, and for one minute, it was visually confirmed through the camera image whether the processing liquid was being discharged normally or not. After one minute, the number of nozzles that were discharging the processing liquid normally was counted. Here, a nozzle that was discharging the processing liquid normally is defined as a nozzle other than those that were not discharging the processing liquid normally (nozzles that were not discharging the processing liquid straight, nozzles that were not discharging the processing liquid, nozzles that were overflowing the processing liquid, etc.). Furthermore, the camera position was moved, and the same check of the processing liquid discharge performance over one minute through the camera image was repeated for other nozzles. A total of 36 nozzles were checked at a total of 12 locations. Finally, the number of nozzles that were discharging the processing liquid normally was totaled, and the discharge performance of the processing liquid was evaluated according to the following criteria. (Judgment criteria) A:36 B:34~35 C:33 or less

[0100] <Friction-fastness> Printed materials were prepared using the treatment solutions obtained in the examples and comparative examples, and the rubbing fastness (wet rubbing fastness and dry rubbing fastness) of each printed material was evaluated.

[0101] (Ink preparation) First, the ink used for printing was prepared. 125 g of deionized water and 2 g of nonionic surfactant (Surfinol® 440, manufactured by Nisshin Chemical Industry Co., Ltd., contents: acetylene glycol ethylene oxide adduct) were placed in a 1 L three-necked flask equipped with a stirring blade. While stirring the contents of the flask, 165 g of propylene glycol, 100 g of black pigment dispersion (AE2078F, manufactured by Sanyo Shikiso Co., Ltd., contents: CIPigment Black 7, solid content concentration: 20% by mass), and 108 g of binder resin particle dispersion (Superflex 470, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., contents: polyurethane dispersion, solid content concentration: 38% by mass) were added to the flask in order. The contents of the flask were stirred for 10 minutes to obtain the ink.

[0102] (Preparation of prints for evaluation) Evaluation prints were prepared using the aforementioned inks and processing solutions 1 to 17.

[0103] The fabric to be printed is cotton broadcloth (manufactured by Irozome Co., Ltd., size: A4, warp and weft cotton count: 40 / 1, warp density: 130 threads / inch, weft density: 75 threads / inch, weight: 122g / m²). 2 An inkjet printer (Seiko Epson Corporation's "Colorio® PX-045A") was used to prepare the evaluation prints. Ink was filled into the first ink chamber of the first cartridge, and processing liquid was filled into the second ink chamber of the second cartridge. Then, the first and second cartridges were installed in the inkjet printer. The ink filled into the first ink chamber was ejected from the inkjet printer's recording head, and the processing liquid filled into the second ink chamber was ejected from the inkjet printer's processing head.

[0104] Using an inkjet printer, the ink ejection rate is 20 g / m². 2 In this manner, ink was ejected from the recording head onto the printing target to form a solid image of ink. Next, using an inkjet printer, the ejection rate of the processing solution was 20 g / m² as described above.2 The processing liquid was discharged from the processing head onto the object to be printed. In this way, a processing film the same size as the solid image was formed on the solid image of the ink by the processing liquid. Next, the object to be printed was heated at 160°C for 3 minutes to dry the ink and processing liquid, and the print for evaluation was prepared. I got it.

[0105] (Method for evaluating frictional fastness) The solid image formed on the evaluation print was rubbed using a white cotton cloth for friction, according to the dry and wet tests of the Type II (JSPS type) friction test machine described in JIS L-0849:2013 (Test method for color fastness to friction). The degree of discoloration of the white cotton cloth for friction after friction was evaluated in accordance with the "criteria for determining discoloration" described in Clause 10 (Determination of color fastness) of JIS L-0801:2011 (General rules for test method for color fastness). The degree of discoloration of the white cotton cloth for friction was judged on a 9-point scale (in descending order of degree of staining: Grade 1, Grade 1-2, Grade 2, Grade 2-3, Grade 3, Grade 3-4, Grade 4, Grade 4-5, and Grade 5). The lower the degree of discoloration of the white cotton cloth for friction (closer to Grade 5), the better the color fastness. From the degree of discoloration of the white cotton cloth for friction after the friction test, the dry color fastness and wet color fastness were evaluated according to the following criteria. The result of the dry test described above was defined as the dry rubbing fastness, and the result of the wet test described above was defined as the wet rubbing fastness. A rating of A or B was considered a pass, and a rating of C was considered a fail. The determined rubbing fastness and its evaluation results are summarized in Table 2 below.

[0106] (Evaluation criteria for dry friction fastness) Rating A: Dry friction fastness is grade 4 or higher. Rating B: Dry friction fastness is grade 3-4. Rating C: Dry friction fastness is grade 3 or lower.

[0107] (Evaluation criteria for wet friction fastness) Rating A: Wet abrasion fastness is Grade 3 or higher. Rating B: Wet abrasion fastness is grade 2-3. Rating C: Wet abrasion fastness is 2nd grade or lower.

[0108] The results of the above evaluation tests are summarized in Table 2.

[0109] [Table 2]

[0110] (Consideration) The results in Table 2 confirm that the processing solution disclosed herein exhibits excellent inkjet ejection properties, and when used for textile printing, it also provides excellent friction fastness to the resulting printed materials. Furthermore, it was confirmed that even after storage at 60°C for 30 days, there was little change in the average particle size of the emulsion particles in the processing solution, and the ejection properties did not deteriorate.

[0111] Furthermore, considering the results of Examples 11-14, it was found that a treatment solution with better storage stability and discharge properties can be obtained if the total surfactant content is within a more favorable range. In other words, Examples 11-14 showed that a low total surfactant content tends to result in poor discharge properties, while a high total surfactant content tends to lead to deterioration of both discharge properties and slightly worse wet friction fastness. In addition, the results of Examples 11-12 showed that if the content of the second surfactant / (content of the first surfactant + content of the second surfactant) is within a predetermined range, better storage stability and discharge properties can be obtained.

[0112] On the other hand, in Comparative Example 1, which used a treatment solution containing only the first surfactant, the average particle size of the emulsion particles increased after 30 days of storage, resulting in a deterioration of the dispensing performance after storage. In other words, Comparative Example 1 showed inferior storage stability.

[0113] In Comparative Example 2, the treatment solution with too little silicone oil content showed poor discharge performance and friction fastness (especially wet friction fastness). In Comparative Example 3, the treatment solution with too much silicone oil content showed poor storage stability, discharge performance, and friction fastness (especially wet friction fastness). [Explanation of symbols]

[0114] 1: Recording head 1a: First recording head 1b: Second recording head 1c: Third recording head 1d: 4th recording head 2: Processing head 3: Mounting platform 10: Inkjet printing equipment P: Printing target

Claims

1. An inkjet processing solution comprising an emulsion containing silicone oil, a surfactant, and an aqueous medium, The surfactant comprises a second surfactant containing an alkyl group having 16 to 18 carbon atoms, and a first surfactant containing an alkyl group having fewer carbon atoms than the alkyl group of the second surfactant. An inkjet processing solution wherein the total content of the first surfactant and the second surfactant is 9.0% by mass or more and 40.0% by mass or less relative to the content of silicone oil.

2. The inkjet processing solution according to claim 1, wherein the surfactant is a polyoxyethylene alkyl ether.

3. The inkjet processing solution according to claim 1, wherein the first surfactant contains two or more compounds having alkyl groups with different numbers of carbon atoms.

4. The inkjet processing solution according to claim 1, wherein the second surfactant contains two or more compounds having alkyl groups with different numbers of carbon atoms.

5. The inkjet processing solution according to claim 1, wherein the content of the second surfactant is less than the content of the first surfactant.

6. The content of the first surfactant and the content of the second surfactant are given by the following formula: The inkjet processing solution according to claim 1, wherein the content of the second surfactant / (content of the first surfactant + content of the second surfactant) = 0.15 to 0.25 (mass%).

7. The inkjet processing solution according to claim 6, wherein the total content of the first surfactant and the second surfactant is 0.5% by mass or more and 4.0% by mass or less of the total processing solution.

8. The inkjet processing solution according to claim 1, wherein the average particle size of the emulsified particles is 100 nm or more and 250 nm or less.

9. When the inkjet processing solution is stored at 60°C for 30 days, the average particle size X of the emulsion particles in the processing solution before storage and the average particle size Y of the emulsion particles in the processing solution after storage are given by the following formula: 1.0 ≤ Y / X ≤ 1.05 An inkjet processing solution according to claim 8, satisfying the requirements.

10. An inkjet processing solution according to any one of claims 1 to 9, for use in textile printing.

11. The system comprises a recording head that ejects ink onto the image-forming region of the object to be printed, and a processing head that ejects processing liquid onto at least the image-forming region of the object to be printed. An inkjet printing apparatus wherein the processing solution is the inkjet processing solution described in any one of claims 1 to 9.

12. The process includes an ink ejection step of ejecting ink from a recording head onto an image forming area of ​​the object to be printed, and a processing step of ejecting a processing liquid from a processing head onto at least the image forming area of ​​the object to be printed. An inkjet printing method wherein the processing solution is an inkjet processing solution according to any one of claims 1 to 9.

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