Inkjet recording treatment liquid

Abstract

Provided are: an inkjet recording treatment liquid containing a polyoxyethylene ether compound (A) having an aromatic ring, a flocculant (B'), and water, wherein the content of the compound (A) is at least 3 mass%; an ink set for inkjet recording; a surface-treated recording medium; an inkjet recording method; and use as an inkjet recording pretreatment liquid. This inkjet recording treatment liquid can provide high-quality printed matter that combines good dot expandability and excellent image uniformity, and can do so even when the treatment liquid is applied to a low-permeability recording medium and then subjected to a thermal drying step.

Description

Inkjet recording treatment liquid

[0001] The present invention relates to a treatment liquid for inkjet recording, an ink set for inkjet recording, a surface-treated recording medium, an inkjet recording method, and use as a pretreatment liquid for inkjet recording.

[0002] Inkjet recording methods have many advantages, such as not requiring plate making, being easily adaptable to variable printing, and not contacting the printed material, and therefore are becoming increasingly popular in a wide range of fields, including office and home use. In recent years, attempts have been made to expand inkjet recording methods to commercial printing and industrial printing applications, which require significantly larger print volumes, and inkjet recording methods are being required to print on recording media made of a variety of materials. In response to these demands, a method has been proposed in which a treatment liquid that intentionally aggregates solid components contained in the ink, such as colorants and resins, is applied to the recording medium before the ink is applied to the recording medium, thereby forming an ink aggregation layer on the recording medium.

[0003] For example, Patent Document 1 describes that by using a treatment liquid containing 1,4-cyclohexanedimethanol, a polyvalent metal salt, and water to treat a recording medium used in inkjet recording, it is possible to obtain a high-quality printed matter that achieves both good dot expandability and excellent image uniformity when using a recording medium with low permeability.

[0004] International Publication No. 2023 / 199982

[0005] With the recent increase in printing speed, when forming an image using ink by inkjet recording on a recording medium that has been surface-treated with a treatment liquid, the treatment liquid can reduce the drying speed of the ink, resulting in ink staining of the transport roller of the printing press due to transfer of the image forming unit to the transport roller. In order to prevent such ink staining of the transport roller and in response to demands for improved handling, such as storage, of recording media that have been surface-treated with a treatment liquid when application of the treatment liquid to the recording medium and printing on the printing press are performed in separate processes, a heat-drying step may be performed after application of the treatment liquid. However, it has been found that the technology disclosed in Patent Document 1 provides insufficient performance when a heat-drying step is performed after application of the treatment liquid to a low-permeability recording medium, leaving room for improvement. An object of the present invention is to provide a treatment liquid for inkjet recording, an ink set for inkjet recording, a surface-treated recording medium, and an inkjet recording method that can produce high-quality printed matter that combines good dot expansion and excellent image uniformity, even when a heat-drying step is performed after application of the treatment liquid to a low-permeability recording medium.

[0006] The present inventors have found that the above-mentioned problems can be solved by an inkjet recording treatment liquid containing a polyoxyethylene ether compound having an aromatic ring, one or more compounds selected from the group consisting of a polyvalent metal salt, a polyvalent amine, and an organic acid, and water, wherein the content of the polyoxyethylene ether compound having an aromatic ring is equal to or greater than a predetermined value. That is, the present invention provides the following [1] to [5]. [1] An inkjet recording treatment liquid containing a polyoxyethylene ether compound having an aromatic ring (A), a flocculant (B'), and water, wherein the content of compound (A) is 3% by mass or more. [2] An inkjet recording ink set comprising the inkjet recording treatment liquid described in [1] above and an ink containing a colorant and water. [3] A surface-treated recording medium treated with the inkjet recording treatment liquid described in [1] above. [4] An inkjet recording method using the inkjet recording treatment liquid described in [1] above, and comprising the following steps 1 and 2: Step 1: A step of applying the treatment liquid to a recording medium, followed by heating and drying to obtain a surface-treated recording medium. Step 2: A step of forming an image on the treated surface of the surface-treated recording medium obtained in Step 1 by an inkjet recording method using an ink containing a colorant and water. [5] Use of a composition as a pretreatment liquid for inkjet recording, comprising a polyoxyethylene ether compound (A) having an aromatic ring, one or more compounds (B) selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids, and water, wherein the content of compound (A) is 3 mass% or more.

[0007] According to the present invention, it is possible to provide a treatment liquid for inkjet recording, an ink set for inkjet recording, a surface-treated recording medium, and an inkjet recording method that are capable of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, even when a heat drying step is performed after the treatment liquid is applied to a low-permeability recording medium.

[0008] [Inkjet Recording Treatment Liquid] The inkjet recording treatment liquid (hereinafter simply referred to as the "treatment liquid") of the present invention contains a polyoxyethylene ether compound (A) having an aromatic ring (hereinafter also referred to as "compound (A)"), a flocculant (B'), and water, with the content of compound (A) being 3% by mass or more. In the present invention, the term "aromatic ring-containing polyoxyethylene ether compound" refers to an ether compound having one or more aromatic rings and two or more ethylene oxide-derived units in one molecule. Note that in the present invention, "containing aromatic ring-containing polyoxyethylene ether compound (A), a flocculant (B'), and water" also means "a mixture of aromatic ring-containing polyoxyethylene ether compound (A), a flocculant (B'), and water." The treatment liquid of the present invention is preferably used to treat a recording medium used in inkjet recording, and more preferably to treat a low-permeability recording medium used in inkjet recording, from the viewpoint of enabling the production of high-quality printed matter in image formation using an inkjet recording method. In other words, the treatment liquid of the present invention is preferably used as a pretreatment liquid for inkjet recording.

[0009] According to the present invention, even when a heat drying process is performed after applying a treatment liquid to a low-permeability recording medium, a high-quality printed matter can be obtained that combines good dot expansion and excellent image uniformity. The reason for this is not entirely clear, but is thought to be as follows: The polyoxyethylene ether compound having an aromatic ring contained in the treatment liquid of the present invention contains units derived from ethylene oxide, which have a high affinity with the solvent components in the ink. It is thought that, when an ink for inkjet recording lands on a recording medium treated with the treatment liquid of the present invention, the ethylene oxide-derived units significantly improve the wettability of the ink with the recording medium, thereby expanding the ink dots. Furthermore, since the polyoxyethylene ether compound having an aromatic ring contains a highly hydrophobic aromatic ring in its molecule, when a resin component is contained in the ink for inkjet recording, the resin component in the ink expands when the ink lands on a recording medium treated with the treatment liquid of the present invention. This promotes uniform thickening of the entire ink dot, causing uniform aggregation, and also suppresses fluctuations in dot expansion behavior due to micro-unevenness in the surface condition of the recording medium, which is thought to improve image uniformity. In addition, it is believed that the aromatic ring-containing polyoxyethylene ether compound has a highly hydrophobic aromatic ring in its molecule, and therefore interacts with the resin components and cellulose fibers contained in the coating layer formed on the surface of a low-permeability recording medium, thereby remaining on the surface even when water and the like are evaporated by heating and drying, thereby achieving the above-mentioned effect.In addition, it is believed that after the treatment liquid of the present invention is applied to a recording medium, the high surfactant effect of the aromatic ring-containing polyoxyethylene ether compound causes the precipitates of coagulants such as polyvalent metal salts, polyvalent amines, and organic acids to be present in small and uniform amounts on the recording medium.Therefore, when ink is applied to a recording medium treated with the treatment liquid of the present invention by inkjet recording, the coagulants such as polyvalent metal salts, polyvalent amines, or organic acids are redissolved uniformly in the aqueous medium contained in the ink, resulting in a uniform coagulation effect and the ink viscosity increasing, which is believed to suppress the occurrence of dot distortion and color mixing, thereby further improving image uniformity.In the present invention, whether a recording medium has low or high permeability is determined by the amount of water absorbed by the recording medium when the recording medium is in contact with pure water for 100 ms. The amount of water absorbed can be measured as the amount of water transferred when the recording medium is in contact with pure water for 100 ms using an automatic scanning absorption meter (for example, KM500win manufactured by Kumagai Riki Kogyo Co., Ltd.) under conditions of 23°C and 50% relative humidity. The term "low permeability" encompasses both low permeability and non-permeability, and refers to a recording medium with a water absorption of 0 g / m. 2 7g / m or more 2 "High permeability" means that the water absorption is 7 g / m or less. 2 It means to be super.

[0010] <Compound (A)> The treatment liquid of the present invention contains a polyoxyethylene ether compound (A) having an aromatic ring. By containing compound (A), the treatment liquid of the present invention can control the wettability of the ink to a low-permeability recording medium, even when the treatment liquid is applied to the low-permeability recording medium and then subjected to a heat drying process. Furthermore, by exhibiting a specific interaction with the coagulant (B') such as a polyvalent metal salt, a polyvalent amine, or an organic acid, it is possible to obtain a high-quality printed matter that combines good dot expandability and excellent image uniformity. The compound (A) can be used alone or in combination of two or more.

[0011] Examples of the compound (A) include polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene dodecylphenyl ether; polyoxyethylene styrenated phenyl ether (including various polyoxyethylene styrenated phenyl ethers such as polyoxyethylene monostyrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tristyrenated phenyl ether), polyoxyethylene phenyl ethers such as polyoxyethylene phenyl ether, polyoxyethylene tribenzyl phenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene bisphenol A ether, and polyoxyethylene bisphenol F ether; and polyoxyethylene benzyl ethers such as diethylene glycol monobenzyl ether, triethylene glycol monobenzyl ether, and polyoxyethylene benzyl ether (polyoxyethylene monobenzyl ether and polyoxyethylene dibenzyl ether. Of these, from the viewpoints of dot expandability and image uniformity on low-permeability recording media, polyoxyethylene phenyl ethers are preferred, and more preferred is at least one selected from the group consisting of polyoxyethylene phenyl ether and polyoxyethylene distyrenated phenyl ether.

[0012] The HLB value of compound (A) is the average value of the compounds contained in compound (A). From the viewpoint of dot expandability and image uniformity on a low-permeability recording medium, the HLB value of compound (A) is preferably 20 or less, more preferably 18 or less, even more preferably 16 or less, even more preferably 15 or less, and even more preferably 14 or less. From the viewpoint of dot expandability and image uniformity on a low-permeability recording medium, the HLB value is preferably 10 or more, more preferably 11 or more, and even more preferably 12 or more. In the present invention, the HLB value is a value indicating the affinity of a surfactant for water and oil as a hydrophile-lipophile balance, and can be calculated using the Griffin method from the following formula. Alternatively, if the value conforms to the Griffin method, the catalog value for each product can also be referenced. HLB value = 20 × [(sum of formula weights of hydrophilic groups contained in the surfactant) / (molecular weight of the surfactant)]. Examples of hydrophilic groups include a hydroxy group and an ethyleneoxy group.

[0013] Examples of commercially available products of compound (A) include Emulgen A-60, A-90, A-500, B-66, etc., manufactured by Kao Corporation; Noigen EA-87, EA-127, EA-137, EA-157, EA-167, EA-177, EA-197D, EA-207D, etc., manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; Braunon DSP-9, DSP-12.5, KTSP-16, TSP-50, PH-5, etc., manufactured by Aoki Oil & Fat Industries Co., Ltd.; and PhG-30 and PhG-55, etc., manufactured by Nippon Nyukazai Co., Ltd.

[0014] <Aggregating Agent (B')> The treatment liquid of the present invention contains an aggregating agent (B'). By containing the aggregating agent (B'), the treatment liquid of the present invention reduces the dispersibility of dispersoids present in the inkjet recording ink, causing the dispersoids to aggregate and thereby thicken or precipitate, thereby suppressing color mixing due to the coalescence of ink dots, improving image uniformity, and enabling the production of high-quality printed matter. In the present invention, the dispersoids present in the inkjet recording ink include not only ink components such as pigments that are currently dispersed in the ink in a solid state, but also ink components that are dissolved in the ink but lose their solubility upon contact with a recording medium treated with the treatment liquid of the present invention, causing thickening or precipitation. Specific examples of ink components that are dissolved in the inkjet recording ink but lose their solubility upon contact with a recording medium treated with the treatment liquid of the present invention, causing thickening or precipitation, include dyes and water-soluble resins. The reason why the dispersibility or solubility of dispersoids present in an inkjet recording ink decreases upon contact with a recording medium treated with the treatment liquid of the present invention is thought to be that when the ink comes into contact with a recording medium treated with the treatment liquid of the present invention, precipitates of the aggregating agent (B') present on the recording medium redissolve in the ink, causing the aggregating agent (B') to thin the thickness of the electric double layer that stabilizes the dispersoids present in the ink, making it impossible to suppress the approach of dispersoids to each other. The aggregating agent (B') is not particularly limited as long as it is a component that reduces the dispersibility of the dispersoids present in the inkjet recording ink and causes the dispersoids to aggregate. Examples include polyvalent metal salts, polyvalent amines, and organic acids. These may be used alone or in combination of two or more. From the viewpoint of dot spreadability and image uniformity on low-permeability recording media, the aggregating agent (B') is preferably one or more selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids. That is, the treatment liquid of the present invention preferably contains one or more compounds (B) (hereinafter also referred to as "compound (B)") selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids. Furthermore, from the viewpoint of dot spreadability and image uniformity on a low-permeability recording medium, compound (B) is more preferably a polyvalent metal salt.As described above, the treatment liquid of the present invention containing compound (A), aggregating agent (B'), and water is preferably used as a pretreatment liquid for inkjet recording from the viewpoint of dot spreadability and image uniformity on a low-permeability recording medium. Furthermore, from the same viewpoint, the aggregating agent (B') is preferably the above-mentioned compound (B). In other words, a composition containing a polyoxyethylene ether compound (A) having an aromatic ring, one or more compounds (B) selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids, and water, in which the content of compound (A) is 3% by mass or more, is suitable for use as a pretreatment liquid for inkjet recording.

[0015] [Polyvalent Metal Salt] Any polyvalent metal salt can be used as long as it is composed of a divalent or higher polyvalent metal ion and an anion (a counterion of the polyvalent metal ion). Examples of divalent or higher polyvalent metal ions include calcium, magnesium, copper, nickel, zinc, barium, aluminum, titanium, strontium, chromium, cobalt, and iron ions. Among these, the polyvalent metal ions constituting the polyvalent metal salt are preferably divalent or trivalent metal ions, more preferably divalent metal ions, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity. Examples of divalent metal ions include ions of elements belonging to Group 2 of the periodic table of elements, specifically magnesium ions, calcium ions, and iron (II) ions. Examples of trivalent metal ions include aluminum ions and iron (III) ions. Among these, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the polyvalent metal ion constituting the polyvalent metal salt is preferably at least one selected from the group consisting of magnesium ions, calcium ions, and aluminum ions, even more preferably at least one selected from the group consisting of magnesium ions and calcium ions, and even more preferably magnesium ions. Examples of anions constituting the polyvalent metal salt include inorganic ions and organic ions. Examples of inorganic ions include monovalent anions such as nitrate ions and halide ions; and divalent anions such as sulfate ions. Examples of organic ions include organic acid ions such as carboxylate ions. Among these, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, as well as from the viewpoints of availability and economy, the anion constituting the polyvalent metal salt is preferably an inorganic ion, more preferably at least one selected from the group consisting of nitrate ions and sulfate ions, and even more preferably nitrate ions.

[0016] From the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity, the polyvalent metal salt is preferably one or more selected from the group consisting of magnesium nitrate, magnesium sulfate, calcium nitrate, and aluminum nitrate, more preferably one or more selected from the group consisting of magnesium nitrate, calcium nitrate, and aluminum nitrate, even more preferably one or more selected from the group consisting of magnesium nitrate and calcium nitrate, and still more preferably magnesium nitrate. The polyvalent metal salt may have water of hydration in the raw material form. The polyvalent metal salt may be used alone or in combination of two or more.

[0017] [Polyamine] Polyamine is a compound having multiple amino groups in the molecule. The amino group of a polyamine is a monovalent functional group (—NH ２ , —NHR, —NRR′). Here, R and R′ represent a hydrocarbon group. The polyvalent amine may be in the form of a salt. Examples of the salt of the polyvalent amine include inorganic acid salts or organic acid salts of the polyvalent amine. Examples of the inorganic acid salt of the polyvalent amine include hydrochloride, sulfate, nitrate, and phosphate. Examples of the organic acid salt of the polyvalent amine include carboxylate and sulfonate. Furthermore, the polyvalent amine may be a quaternary ammonium salt in which the amino group is quaternized with a quaternizing agent.

[0018] The polyvalent amine may be an alkanediamine. From the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the alkanediamine is preferably at least one selected from the group consisting of ethylenediamine (1,2-diaminoethane), 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, and 1,8-octamethylenediamine.

[0019] As the polyvalent amine, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, a polymer having multiple amino groups in the molecule (hereinafter also referred to as an "amino group-containing polymer") is preferred. The amino group-containing polymer is preferably a polymer containing a structural unit derived from a polymerizable monomer having at least one amino group. The amino group-containing polymer may be in the form of a salt, or may be a quaternary ammonium salt in which the amino group is quaternized with a quaternizing agent.

[0020] From the viewpoints of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, availability, and economy, preferred examples of the amino group-containing polymer and its salt include one or more selected from the group consisting of polyethyleneimine, polyvinylamine, polyallylamine, polydiallylmethylamine, polydiallylethylamine, dimethylamine / epichlorohydrin copolymer, dimethylamine / ammonia / epichlorohydrin copolymer, and salts thereof. From the viewpoints of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, availability, and economy, preferred examples of the quaternary ammonium salt of the amino group-containing polymer include diallyl quaternized ammonium salt polymer, more preferably one or more selected from the group consisting of polydiallyldimethylammonium chloride, polydiallyldiethylammonium chloride, polydiallylmethylethylammonium ethyl sulfate, diallyldimethylammonium chloride / acrylic acid copolymer, diallyldimethylammonium chloride / acrylamide copolymer, and diallyldimethylammonium chloride / acrylic acid / acrylamide copolymer.

[0021] The polyvalent amine is preferably in the form of a polyvalent amine salt. The polyvalent amine salt is preferably a salt of an amino group-containing polymer, from the viewpoint of increasing the density of the salt to significantly exhibit the effect of reducing the dispersibility or solubility of dispersoids present in the inkjet recording ink, thereby obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity. More preferably, the salt is at least one selected from the group consisting of polydiallyldimethylammonium chloride, polydiallylmethylethylammonium ethyl sulfate, dimethylamine / epichlorohydrin copolymer, polyethyleneimine hydrochloride, and polyallylamine hydrochloride, and even more preferably at least one selected from the group consisting of polydiallyldimethylammonium chloride and dimethylamine / epichlorohydrin copolymer. From the same viewpoint, the salt of the amino group-containing polymer is preferably polydiallyldimethylammonium chloride or dimethylamine / epichlorohydrin copolymer. From the viewpoint of dot expandability after drying, polydiallyldimethylammonium chloride is more preferred, and from the viewpoint of image quality uniformity after drying, dimethylamine / epichlorohydrin copolymer is more preferred. The weight-average molecular weight of the amino group-containing polymer salt is preferably 5,000 or more from the viewpoint of increasing the salt density and improving image uniformity of printed matter when using a low-permeability recording medium. Furthermore, from the viewpoint of suppressing thickening of the treatment liquid, uniformly applying the treatment liquid to the recording medium, and improving image uniformity of printed matter, it is preferably 100,000 or less, more preferably 50,000 or less, and even more preferably 25,000 or less. The average molecular weight of the amino group-containing polymer salt can be measured by gel permeation chromatography (GPC). Furthermore, when using a commercially available product as the amino group-containing polymer salt, the average molecular weight of the amino group-containing polymer salt can be determined by referring to the catalog value of each commercially available product. Suitable examples of commercially available amino group-containing polymer salts include the "PAS" series manufactured by Nittobo Medical Co., Ltd. and the "Unisense" series manufactured by Senka Corporation. The polyvalent amines can be used alone or in combination of two or more.

[0022] [Organic Acid] The organic acid may be added to the treatment solution in the form of an acid or a salt, but is preferably added in the form of a salt. Preferred examples of the organic acid include monocarboxylic acids such as acetic acid and propionic acid; polycarboxylic acids such as poly(meth)acrylic acid, oxalic acid, malonic acid, maleic acid, succinic acid, glutaric acid, and fumaric acid; hydroxycarboxylic acids such as ascorbic acid, glycolic acid, malic acid, citric acid, tartaric acid, and lactic acid; heterocyclic ring-containing carboxylic acids such as pyrrolidonecarboxylic acid, pyrronecarboxylic acid, pyrrolecarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumaric acid, thiophenecarboxylic acid, and nicotinic acid, or derivatives of these compounds. From the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the organic acid is preferably a hydroxycarboxylic acid, more preferably a hydroxypolycarboxylic acid, even more preferably one or more selected from citric acid, tartaric acid, and lactic acid, and even more preferably lactic acid. The organic acid may also be in the form of a salt. However, when an organic acid forms a metal salt, it is included in the above-mentioned polyvalent metal salt. As the salt of an organic acid, an ammonium salt is preferred from the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity. The organic acid may be used alone or in combination of two or more kinds.

[0023] From the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the treatment liquid of the present invention preferably contains as compound (A) one or more compounds selected from the group consisting of polyoxyethylene phenyl ether and polyoxyethylene styrenated phenyl ether, and as compound (B) a polyvalent metal salt; more preferably contains as compound (A) one or more compounds selected from the group consisting of polyoxyethylene phenyl ether and polyoxyethylene styrenated phenyl ether, and as compound (B) one or more polyvalent metal salts selected from the group consisting of magnesium nitrate, calcium nitrate, and aluminum nitrate; still more preferably contains as compound (A) one or more compounds selected from the group consisting of polyoxyethylene phenyl ether and polyoxyethylene styrenated phenyl ether, and as compound (B) one or more polyvalent metal salts selected from the group consisting of magnesium nitrate and calcium nitrate; and still more preferably contains as compound (A) one or more compounds selected from the group consisting of polyoxyethylene phenyl ether and polyoxyethylene styrenated phenyl ether, and as compound (B) one or more polyvalent metal salts selected from the group consisting of magnesium nitrate and calcium nitrate.

[0024] <Water> The treatment liquid of the present invention contains water. The water used in the treatment liquid of the present invention is preferably pure water or ion-exchanged water from the viewpoint of preventing the inclusion of unintended substances.

[0025] The treatment liquid of the present invention may further contain, as necessary, other components besides the compound (A) and the compound (B), such as a water-soluble organic solvent, a pH adjuster, a surfactant, a colorant, an antifoaming agent, an antiseptic / fungal agent, and a rust inhibitor.

[0026] (Water-soluble organic solvent) The treatment liquid of the present invention may further contain a water-soluble organic solvent, from the viewpoint of ensuring sufficient solubility of compound (A) in the treatment liquid and obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity. Examples of the water-soluble organic solvent include polyhydric alcohols; ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers; nitrogen-containing heterocyclic compounds; amides; amines; and sulfur-containing compounds.

[0027] Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol (1,2-propanediol), 1,3-propylene glycol, dipropylene glycol (isomer mixture), 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3- Examples of diols include pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, 1,7-heptanediol, 1,8-octanediol, and 1,2-octanediol.

[0028] Examples of polyhydric alcohol alkyl ethers include (poly)alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, and dipropylene glycol monoethyl ether. Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether. Examples of nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and ε-caprolactam. Examples of amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide. Examples of amines include monoethanolamine, diethanolamine, triethanolamine, and triethylamine. These compounds are also used as pH adjusters. Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiodiethanol. Examples of water-soluble organic solvents other than those mentioned above include propylene carbonate and ethylene carbonate.

[0029] Among these, when a water-soluble organic solvent is used, the water-soluble organic solvent is preferably at least one selected from the group consisting of polyhydric alcohols and polyhydric alcohol alkyl ethers, more preferably polyhydric alcohols, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity. From the same viewpoint as above, the polyhydric alcohol is preferably a diol, more preferably at least one selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol (1,2-propanediol), 1,3-propylene glycol, dipropylene glycol (isomer mixture), 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol, and even more preferably at least one selected from the group consisting of diethylene glycol, propylene glycol (1,2-propanediol), and dipropylene glycol (isomer mixture). From the same viewpoint as above, the polyhydric alcohol alkyl ether is preferably a (poly)alkylene glycol monoalkyl ether, more preferably at least one selected from the group consisting of ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether, and even more preferably at least one selected from the group consisting of diethylene glycol monobutyl ether and triethylene glycol monobutyl ether. The water-soluble organic solvents can be used singly or in combination of two or more.

[0030] (pH Adjuster) The treatment solution of the present invention may contain a pH adjuster. The pH adjuster refers to an agent that suppresses pH fluctuations due to environmental changes and maintains a constant pH of the treatment solution. The pH adjuster can be selected as appropriate depending on the pH of the treatment solution of the present invention. Examples of basic compounds that can be used as pH adjusters to basify the treatment solution of the present invention include alkanolamines such as dimethylethanolamine, diethanolamine, triethanolamine, and N-methyldiethanolamine; primary amines, secondary amines, tertiary amines, and quaternary ammonium salts; ammonia water; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; and alkali metal carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, and sodium bicarbonate. When the pH adjuster is an alkanolamine, primary amine, secondary amine, tertiary amine, or quaternary ammonium salt, it is preferable that these amines or quaternary ammonium salts be monovalent. Examples of acidic compounds used as pH adjusters to acidify the treatment solution of the present invention include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and boric acid; organic acids such as acetic acid, citric acid, succinic acid, tartaric acid, malic acid, fumaric acid, malonic acid, ascorbic acid, and glutamic acid; and alkali metal acetates such as lithium acetate and sodium acetate. These pH adjusters can be used alone or in combination of two or more.

[0031] (Surfactant) The treatment liquid of the present invention may contain a surfactant. The surfactant is preferably a nonionic surfactant. Examples of nonionic surfactants include polyoxyalkylene alkyl ether surfactants, acetylene alcohol surfactants such as acetylene glycol surfactants, polyhydric alcohol surfactants, fatty acid alkanolamides, silicone surfactants, and fluorine-based surfactants. Among these, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the surfactant is preferably an acetylene alcohol surfactant, and more preferably an acetylene glycol surfactant. Examples of acetylene glycol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and ethylene oxide adducts of these diols. Examples of acetylene alcohol surfactants other than acetylene glycol surfactants include 3,5-dimethyl-1-hexyn-3-ol, 2,4-dimethyl-5-hexyn-3-ol, and ethylene oxide adducts of these monools. The sum (n) of the average number of moles of ethyleneoxy groups (EO) added in the ethylene oxide adducts is preferably 0 or more and preferably 20 or less, more preferably 10 or less, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity. Commercially available examples of nonionic surfactants include the "Surfynol" series manufactured by Nissin Chemical Industry Co., Ltd. and Air Products & Chemicals, and the "Acetylenol" series manufactured by Kawaken Fine Chemicals Co., Ltd. The surfactants can be used alone or in combination of two or more.

[0032] The treatment liquid of the present invention may contain a colorant, as described below, to the extent that the effects of the present invention are not impaired. When the treatment liquid of the present invention contains a colorant, the colorant is preferably a pigment or a hydrophobic dye from the viewpoint of water resistance, and is preferably a pigment from the viewpoint of achieving high weather resistance.

[0033] (Composition of Treatment Liquid) From the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity, the content of compound (A) in the treatment liquid of the present invention is 3% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more. From the same viewpoint as above and from the viewpoint of economy, it is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 45% by mass or less, and even more preferably 40% by mass or less. Furthermore, from the viewpoint of improving dot expandability, it is even more preferably 30% by mass or more, even more preferably 35% by mass or more. Furthermore, from the viewpoint of improving image uniformity, it is even more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0034] From the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the content of compound (B) in the treatment liquid of the present invention is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, still more preferably 10% by mass or more, and still more preferably 13% by mass or more, and from the same viewpoint as above, it is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, still more preferably 25% by mass or less, still more preferably 20% by mass or less, and still more preferably 17% by mass or less. When compound (B) is used in the form of a hydrate having water of hydration as the raw material form of the polyvalent metal salt, the content of the polyvalent metal salt in the treatment liquid of the present invention means the content of the anhydrous polyvalent metal salt.

[0035] From the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the water content in the treatment liquid of the present invention is preferably 85% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, still more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less, and from the same viewpoint as above and from the viewpoint of economy, it is preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, still more preferably 35% by mass or more, and even more preferably 40% by mass or more. When the polyvalent metal salt is used in the form of a hydrate having water of hydration as a raw material, the water content in the treatment liquid of the present invention means the amount including the water content from the hydrate of the polyvalent metal salt.

[0036] The mass ratio of the content of compound (B) to the content of compound (A) in the treatment liquid of the present invention [compound (B) / compound (A)] is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and still more preferably 0.4 or more, from the viewpoints similar to those mentioned above, and is preferably 15 or less, more preferably less than 15, even more preferably 8 or less, still more preferably 4 or less, still more preferably 3 or less, still more preferably 2 or less, still more preferably 1 or less, and still more preferably 0.80 or less.

[0037] The mass ratio of the content of compound (A) to the content of water in the treatment liquid of the present invention [compound (A) / water] is preferably 0.01 or more, more preferably 0.04 or more, even more preferably 0.06 or more, still more preferably 0.07 or more, still more preferably 0.10 or more, and even more preferably 0.15 or more from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, and from the same viewpoint as above and from the viewpoint of economy, it is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.0 or less. Furthermore, from the viewpoint of improving image uniformity, it is even more preferably 0.20 or more, even more preferably 0.25 or more, even more preferably 0.5 or more, and even more preferably 0.8 or more, and from the viewpoint of improving dot expandability, it is even more preferably 0.50 or less, even more preferably 0.40 or less, and even more preferably 0.20 or less.

[0038] When the treatment liquid of the present invention further contains a water-soluble organic solvent, the content of the water-soluble organic solvent in the treatment liquid is preferably 30% by mass or less, more preferably 15% by mass or less, even more preferably 5% by mass or less, and still more preferably 2% by mass or less, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity. When two or more water-soluble organic solvents are used in the treatment liquid of the present invention, the content is the total content of the water-soluble organic solvents.

[0039] The content of the colorant in the treatment liquid of the present invention is preferably 1% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and even more preferably 0% by mass, i.e., it is even more preferable that the treatment liquid of the present invention does not contain any colorant. If the content of the colorant in the treatment liquid of the present invention is within the above range, when the treatment liquid is used together with an ink for inkjet recording to perform inkjet recording, an image can be formed without affecting the hue of the ink.

[0040] The viscosity of the treatment liquid of the present invention is not particularly limited, but from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the viscosity of the treatment liquid at 25°C is preferably 1 mPa·s or more, more preferably 3 mPa·s or more, even more preferably 4 mPa·s or more, and is preferably 100 mPa·s or less, more preferably 80 mPa·s or less, even more preferably 50 mPa·s or less, still more preferably 30 mPa·s or less, even more preferably 20 mPa·s or less, and still more preferably 10 mPa·s or less. The viscosity of the treatment liquid of the present invention is measured by the method described in the Examples. From the viewpoint of preventing metal corrosion of members, the pH of the treatment liquid of the present invention at 20°C is preferably 3.5 or more, more preferably 4 or more, even more preferably 4.5 or more, still more preferably 5 or more, even more preferably 6 or more, even more preferably 7 or more, and is preferably 11.0 or less, more preferably 10.5 or less, and still more preferably 10.0 or less. The pH of the treatment solution of the present invention is measured by the method described in the examples.

[0041] (Preparation of Treatment Solution) The treatment solution of the present invention is prepared by appropriately mixing Compound (A), Compound (B), water, and, if necessary, the other components described above. The pH of the treatment solution can be appropriately adjusted using the pH adjuster described above.

[0042] [Inkjet Recording Ink Set] <Inkjet Recording Ink> Hereinafter, an inkjet recording ink that can be applied to a recording medium treated with the treatment liquid of the present invention (hereinafter also referred to as a "surface-treated recording medium") will be described. From the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity, the inkjet recording ink preferably contains a colorant and water. That is, in the present invention, the treatment liquid can be used as an inkjet recording ink set together with an ink containing a colorant and water.

[0043] [Colorant] Either a dye or a pigment can be used as the colorant for the inkjet recording ink. Among these, it is preferable to use a pigment as the colorant from the viewpoint of water resistance, light resistance, weather resistance, gas resistance, etc. The pigment can be either a known organic pigment or an inorganic pigment. One type of pigment may be used alone, or two or more types may be used in combination, or a mixed crystal may be used. Examples of inorganic pigments include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow. Furthermore, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used as the inorganic pigment. Examples of organic pigments include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. Examples of pigments that can be used include hollow particles such as resin hollow particles and inorganic hollow particles. Glossy color pigments such as gold and silver, or metallic pigments, can also be used. Specific examples of pigments for black inks include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper, iron (C.I. Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (C.I. Pigment Black 1). Specific examples of pigments for chromatic inks include C.I. Examples of the pigment include one or more products having product numbers selected from the group consisting of C.I. Pigment Yellow, C.I. Pigment Orange, C.I. Pigment Red, C.I. Pigment Violet, C.I. Pigment Blue, and C.I. Pigment Green.

[0044] The dye is not particularly limited, and examples thereof include acid dyes, basic dyes, direct dyes, reactive dyes, etc. The dyes may be used alone or in combination of two or more. Examples of the dye include C.I. Acid Yellow, C.I. Acid Red, C.I. Acid Blue, C.I. Acid Black, C.I. Food Black, C.I. Direct Yellow, C.I. Direct Red, C.I. Direct Blue, C.I. Direct Black, C.I. Reactive Red, and C.I. Reactive Black.

[0045] When the inkjet recording ink contains a pigment, the pigment is dispersed in a medium in the ink. Examples of the form of the pigment in the inkjet recording ink include a form in which the pigment is dispersed using a resin (hereinafter also referred to as a "pigment dispersion resin") or a surfactant as a dispersant, and a form in which the pigment is self-dispersed without using a dispersant. Among these, the form in which the pigment is dispersed using a pigment dispersion resin is preferred. The pigment dispersion resin may be either a water-soluble resin or a water-insoluble resin. Regarding the "water-soluble" and "water-insoluble" of a resin, when a resin that has reached a constant weight after drying at 105°C for 2 hours is dissolved in 100 g of water at 25°C until saturation is reached, the resin is judged to be "water-soluble" if the dissolved amount exceeds 10 g, and "water-insoluble" if the dissolved amount is 10 g or less. Furthermore, as will be described later, when the resin has an anionic group and the anionic group is further neutralized with a neutralizing agent, the dissolution amount is determined by measuring the dissolution amount in the presence of a neutralizing agent such that the mass ratio of the resin to the neutralizing agent is the same as that in the inkjet recording ink.

[0046] Specific examples of the form of the pigment in the inkjet recording ink, from the viewpoint of improving the dispersion stability of the pigment, include (a) a form in which a water-soluble resin is adsorbed onto the surface of the pigment, (b) a form in which a water-soluble surfactant or a water-dispersible surfactant is adsorbed onto the surface of the pigment, (c) a form of a self-dispersing pigment in which a hydrophilic functional group is chemically or physically introduced onto the surface of the pigment and the pigment is dispersed without using a pigment dispersing resin or a surfactant, and (d) a form in which the pigment is coated with a water-insoluble resin.

[0047] The pigments having the above-mentioned forms (a) to (d) preferably have anionic properties. This allows polyvalent metal ions derived from a polyvalent metal salt contained in the treatment liquid or ammonium cations derived from amino groups of a polyvalent amine to electrostatically interact with the anionic properties of the pigment surface, reducing the dispersibility of the pigment present in the ink and causing it to aggregate. As a result, it is believed that high-quality printed matter that combines good dot expandability and excellent image uniformity can be obtained when using a low-permeability recording medium. From this perspective, in form (a), the water-soluble resin preferably has an anionic group; in form (b), the water-soluble surfactant or water-dispersible surfactant preferably has an anionic group; in form (c), the hydrophilic functional group introduced onto the pigment surface preferably has an anionic group; and in form (d), the water-insoluble resin preferably has an anionic group. Examples of anionic groups include a carboxy group (-COOM), a sulfonic acid group (-SO ３ M), phosphate group (-OPO ３ M ２ ) or their dissociated ionic forms (-COO － , -SO ３ － , -OPO ３ ２－ , -OPO ３ － In the above chemical formula, M represents a hydrogen atom, an alkali metal, ammonium, or an organic ammonium.

[0048] Among these, from the viewpoint of reducing the dispersibility of dispersoids present in the ink by polyvalent metal ions and / or polyvalent amines to favorably exhibit the aggregation effect, and from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity when using a low-permeability recording medium, the form of the pigment in the inkjet recording ink is preferably one or more forms selected from the group consisting of form (c) and form (d), and more preferably form (d). When the form of the pigment in the inkjet recording ink is form (d), examples of the form in which the pigment is coated with a water-insoluble resin include a form in which the water-insoluble resin encapsulates the pigment, a form in which the pigment is uniformly dispersed in the water-insoluble resin, a form in which the pigment is exposed from the surface of water-insoluble resin particles, and a form in which the water-insoluble resin is adsorbed to the pigment. When the form of the pigment in the inkjet recording ink is form (d), the form in which the pigment is coated with a water-insoluble resin having a crosslinked structure is preferred. In the case where a pigment is coated with a water-insoluble resin having a crosslinked structure, the water-insoluble resin preferably has a structure containing a polymer component having a linear two-dimensional structure which may have branched chains and a component derived from a crosslinking agent. Such a crosslinked structure is considered to be a three-dimensional structure formed by the polymer having a linear two-dimensional structure which may have branched chains and the component derived from the crosslinking agent.

[0049] When the inkjet recording ink is in the form (d), the type of water-insoluble resin used as the pigment dispersing resin for dispersing the pigment is not particularly limited. Specific examples of water-insoluble resins include (meth)acrylic resins, styrene / (meth)acrylic resins, maleic acid resins, styrene / maleic acid resins, urethane resins, and polyester resins. Among these, the water-insoluble resin is preferably one or more selected from the group consisting of (meth)acrylic resins, styrene / (meth)acrylic resins, urethane resins, and polyester resins, from the viewpoint of reducing the dispersibility of dispersoids present in the ink due to polyvalent metal ions derived from polyvalent metal salts or ammonium cations derived from amino groups of polyvalent amines, thereby easily controlling the aggregation effect, and from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity when using low-permeability recording media. More preferably, the water-insoluble resin is one or more selected from the group consisting of (meth)acrylic resins and styrene / (meth)acrylic resins. In this specification, "(meth)acrylic" refers to acrylic or methacrylic. The water-insoluble resin may be synthesized by a known method, or a commercially available product may be used. The water-insoluble resin may be used alone or in combination of two or more kinds.

[0050] The number average molecular weight of the pigment dispersion resin is preferably 5,000 or more, more preferably 7,000 or more, even more preferably 10,000 or more, and preferably 100,000 or less, more preferably 50,000 or less, even more preferably 30,000 or less. The number average molecular weight is measured by the method described in the Examples. The acid value of the pigment dispersion resin is preferably 5 mgKOH / g or more, more preferably 50 mgKOH / g or more, even more preferably 100 mgKOH / g or more, even more preferably 150 mgKOH / g or more, even more preferably 200 mgKOH / g or more, and preferably 800 mgKOH / g or less, more preferably 500 mgKOH / g or less, even more preferably 300 mgKOH / g or less. The acid value of the pigment dispersion resin can be determined by the method described in the Examples, but it can also be calculated from the mass ratio of the constituent monomers.

[0051] [Fixing Resin] The inkjet recording ink may contain a resin (hereinafter also referred to as "fixing resin") that functions as a fixing aid. The fixing resin in the inkjet recording ink is preferably in the form of a resin that does not coat the pigment, and more preferably in the form of resin particles that do not contain a pigment. The fixing resin is not particularly limited and can be appropriately selected depending on the purpose. Specific examples of fixing resins include urethane resins, polyester resins, acrylic resins, vinyl acetate resins, styrene resins, butadiene resins, styrene / butadiene resins, vinyl chloride resins, styrene / acrylic resins, and acrylic silicone resins. An ink can be obtained by mixing a particulate fixing resin with a colorant, water, an organic solvent, etc. The fixing resin may be synthesized or commercially available. One fixing resin may be used alone, or two or more fixing resins may be used in combination.

[0052] [Wax] The inkjet recording ink may contain wax. In this specification, "wax" refers to an organic substance that is solid or semi-solid at room temperature (25°C) and becomes liquid when heated. Here, "semi-solid wax" means that the wax deforms and flows when force is applied to it, but can maintain a certain shape when no force is applied to it. The temperature at which the wax becomes liquid when heated, i.e., the melting point of the wax, is in the temperature range of 45°C or higher. The wax may be either natural or synthetic. Examples of natural waxes include petroleum-based waxes such as paraffin wax and microcrystalline wax; plant-based waxes such as carnauba wax, candelilla wax, and rice wax; and animal-based waxes such as lanolin and beeswax. Examples of synthetic waxes include synthetic hydrocarbon waxes such as polyolefin wax and Fischer-Tropsch wax; silicone-based waxes; and modified waxes such as paraffin wax derivatives, montan wax derivatives, and microcrystalline wax derivatives. Among these, polyolefin waxes primarily composed of olefin-based monomers are preferred. The waxes can be used alone or in combination of two or more.

[0053] The inkjet recording ink preferably contains wax as a dispersion (hereinafter also referred to as "wax dispersion"). The wax dispersion is not particularly limited, and examples thereof include those prepared by emulsifying wax with a known surfactant. Examples of the surfactant that can be used include nonionic surfactants and anionic surfactants. Examples of the nonionic surfactant include ethylene oxide adducts of higher alcohols and ethylene oxide adducts of alkylated phenols. Examples of the anionic surfactant include sulfate ester salts and phosphate ester salts based on ethylene oxide adducts of higher alcohols; alkylated benzenesulfonates, and the like. Among these, from the viewpoint of improving the ejection stability of the ink and the image fastness of printed matter, the wax dispersion is preferably a nonionic wax dispersion prepared by emulsifying wax with a nonionic surfactant, and more preferably a nonionic polyolefin wax dispersion. Suitable examples of commercially available wax dispersions include the "Hi-Tec E" series manufactured by Toho Chemical Industry Co., Ltd., the "AQUACER" series manufactured by BYK Corporation, the "Cellosol" series manufactured by Chukyo Yushi Co., Ltd., and the "Chemipearl" series manufactured by Mitsui Chemicals, Inc.

[0054] [Water] The medium of the inkjet recording ink is preferably an aqueous medium. That is, the inkjet recording ink is preferably an aqueous ink containing water. Here, "aqueous" means that water accounts for the largest proportion by mass of the medium of the inkjet recording ink. When the medium of the inkjet recording ink is an aqueous medium, the aqueous medium contained in the ink is supplied to a recording medium treated with the treatment liquid, and the polyvalent metal salt, polyvalent amine, or organic acid precipitated on the recording medium is redissolved. This is thought to enable the production of high-quality printed matter that combines good dot expandability and excellent image uniformity when using a low-permeability recording medium. The water contained in the inkjet recording ink is preferably ion-exchanged water, deionized water, or distilled water.

[0055] [Water-Soluble Organic Solvent] The inkjet recording ink may further contain a water-soluble organic solvent as an aqueous medium. Examples of the water-soluble organic solvent contained in the ink include polyhydric alcohols exemplified as the water-soluble organic solvents used in the treatment liquid described above; ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers; nitrogen-containing heterocyclic compounds; amides; amines; and sulfur-containing compounds. Among these, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, the water-soluble organic solvent is preferably at least one selected from the group consisting of polyhydric alcohols and polyhydric alcohol alkyl ethers, and more preferably a combination of a polyhydric alcohol and a polyhydric alcohol alkyl ether. From the viewpoint of environmental friendliness, the water content in the aqueous medium of the inkjet recording ink is preferably 51% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, still more preferably 65% ​​by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and still more preferably 80% by mass or less.

[0056] The inkjet recording ink may contain surfactants, antifoaming agents, antiseptics and fungicides, rust inhibitors, pH adjusters, and the like, as needed.

[0057] (Composition of Inkjet Recording Ink) The content of the colorant in the inkjet recording ink is preferably 2% by mass or more, more preferably 3% by mass or more, and even more preferably 4% by mass or more, from the viewpoint of improving the image density of the printed matter. Furthermore, from the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity, it is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. When the inkjet recording ink contains a pigment dispersing resin, the content of the pigment dispersing resin in the ink is preferably 2% by mass or more, more preferably 4% by mass or more, and even more preferably 6% by mass or more, from the viewpoint of pigment dispersion stability and obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity. Furthermore, from the viewpoint of improving the image density of the printed matter, it is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. When the inkjet recording ink contains a pigment dispersing resin, the mass ratio of the pigment content to the pigment dispersing resin content in the ink [pigment / pigment dispersing resin] is preferably 0.30 or more, more preferably 0.50 or more, and even more preferably 0.70 or more, from the viewpoint of improving the image density of the printed matter, and is preferably 1.00 or less, more preferably 0.90 or less, and even more preferably 0.80 or less, from the viewpoint of pigment dispersion stability and obtaining high-quality printed matters that combine good dot expandability and excellent image uniformity. When the inkjet recording ink contains a fixing resin, the content of the fixing resin in the ink is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more, from the viewpoint of obtaining high-quality printed matters that combine good dot expandability and excellent image uniformity. And is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of improving the image density of the printed matter.When the inkjet recording ink contains a wax, the content of the wax in the ink is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and preferably 7% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity. When the inkjet recording ink contains a water-soluble organic solvent, the content of the water-soluble organic solvent in the ink is preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less, from the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity.

[0023] When the inkjet recording ink contains a water-soluble organic solvent and a polyhydric alcohol and a polyhydric alcohol alkyl ether are used in combination as the water-soluble organic solvent, the mass ratio of the polyhydric alcohol alkyl ether content to the polyhydric alcohol content in the ink [polyhydric alcohol alkyl ethers / polyhydric alcohols] is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and preferably 0.9 or less, more preferably 0.7 or less, and even more preferably 0.5 or less, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity. The water content in the inkjet recording ink is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, still more preferably 55% by mass or more, and preferably 75% by mass or less, more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less, from the viewpoint of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity.

[0058] [Inkjet Recording Method] The inkjet recording method using the treatment liquid of the present invention is preferably a method of forming an image by inkjet recording using an ink for inkjet recording on the treated surface of a surface-treated recording medium that has been treated with the treatment liquid, and more preferably a method including the following steps 1 and 2: Step 1: A step of applying the treatment liquid to a recording medium and then heating and drying to obtain a surface-treated recording medium; Step 2: A step of forming an image by inkjet recording using an ink containing a colorant and water on the treated surface of the surface-treated recording medium obtained in step 1.

[0059] (Step 1) Step 1 is a step in which the treatment liquid is applied to a recording medium and then heated and dried to obtain a surface-treated recording medium. In the present invention, the recording medium used in Step 1 can be either a low-permeability recording medium or a high-permeability recording medium. However, from the viewpoint of good dot spreadability and excellent image uniformity, it is preferable to use a low-permeability recording medium. Examples of low-permeability recording media include low-water-absorbency coated paper and non-water-absorbency resin films. Examples of coated paper include general-purpose glossy paper and multicolor foam gloss paper. The resin film is preferably at least one selected from the group consisting of polyester film, polyvinyl chloride film, polypropylene film, and polyethylene film. These resin films may be surface-treated, such as by corona treatment. Examples of high-permeability recording media include highly water-absorbency plain paper.

[0060] The method for applying the treatment liquid to the recording medium is not particularly limited. Examples of methods for applying the treatment liquid to the recording medium include immersion, roller application, spray application, brush application, and application by inkjet recording. Among these, roller application is preferred from the viewpoint of applying the treatment liquid simply and uniformly. Roller application methods include (i) a method in which the treatment liquid is held in a gap between the recording medium and a member in contact with the recording medium, and one of the recording medium and the member in contact with the recording medium is moved to spread the treatment liquid applied to a portion of the recording medium over the entire recording medium, thereby obtaining a surface-treated recording medium treated with the treatment liquid; or (ii) a method in which the recording medium and a member in contact with the recording medium or adjacent to the recording medium with a small gap are rotated to print the treatment liquid on the recording medium or absorb the treatment liquid held in the small gap into the recording medium. Specific examples of rollers used for roller application include offset gravure coaters, gravure coaters, doctor coaters, bar coaters, blade coaters, flexographic coaters, and roll coaters. Among these, one or more types selected from the group consisting of a doctor coater, a bar coater, and a roll coater are preferred. From the viewpoint of being able to continuously perform steps 1 and 2, the device used to apply the treatment liquid to the recording medium is preferably one that integrates a means for applying the treatment liquid used in step 1, a heat drying means used in step 1, and a means for applying the ink for inkjet recording used in step 2. In this case, for example, the means for applying the treatment liquid, such as a roller coater, may be incorporated into the inkjet recording device described below.

[0061] The amount of the treatment liquid applied to the recording medium is preferably 0.2 g / m from the viewpoint of obtaining a high-quality print that combines good dot spreadability and excellent image uniformity. ２ More preferably, 0.5 g / m ２ More preferably, 1 g / m ２ More preferably, 1.3 g / m ２ From the same viewpoint as above, it is preferably 5 g / m ２ Less than 2 g / m, more preferably２ More preferably, 1.8 g / m or less ２ The following is the result.

[0062] In step 1, from the viewpoint of obtaining a high-quality printed matter that combines good dot expandability and excellent image uniformity, after applying the treatment liquid to the recording medium, the treatment liquid on the recording medium may be dried at room temperature before being dried by heating. Examples of room-temperature drying methods in step 1 include static drying, air drying, and reduced-pressure drying. In the recording method of the present invention, application of active energy rays such as ultraviolet rays and radiation is not included in the drying of the present invention. The temperature during room-temperature drying in step 1 is preferably 45°C or less, more preferably 40°C or less, even more preferably 38°C or less, and even more preferably 30°C or less, from the viewpoint of suppressing deformation of the recording medium. Furthermore, from the viewpoint of drying within a short period of time, the temperature is preferably 20°C or more, more preferably 25°C or more. The time for room-temperature drying in step 1 is preferably 0.5 minutes or more, more preferably 1 minute or more, even more preferably 5 minutes or more, and is preferably 30 minutes or less, more preferably 20 minutes or less, and even more preferably 10 minutes or less.

[0063] The temperature during heat drying in step 1 is preferably 50°C or higher, more preferably 70°C or higher, and even more preferably 90°C or higher, from the viewpoint of drying in a short time. From the viewpoint of suppressing deformation of the recording medium, it is preferably 125°C or lower, more preferably 123°C or lower, and even more preferably 120°C or lower. The temperature during heat drying in step 1 is preferably determined by measuring the temperature of the treated surface of the surface-treated recording medium with a non-contact thermometer. Alternatively, the temperature measured by the heat drying means may be used. The heat drying time in step 1 is preferably 10 seconds or longer, more preferably 20 seconds or longer, and even more preferably 30 seconds or longer. From the viewpoint of suppressing deformation of the recording medium and improving the recording speed, it is preferably 180 seconds or shorter, more preferably 120 seconds or shorter, and even more preferably 100 seconds or shorter. Suitable means for heat drying the surface-treated recording medium include a method of blowing a gas adjusted to the aforementioned temperature, a method of holding or passing the surface-treated recording medium through a gas atmosphere adjusted to the aforementioned temperature, a method of irradiating the treated surface of the surface-treated recording medium with an infrared heater, and a method of heating with a platen heater.

[0064] (Step 2) Step 2 is a step of forming an image by inkjet recording using an inkjet recording ink on the treated surface of the surface-treated recording medium obtained in step 1. The inkjet recording ink is loaded into a known inkjet recording device, and is deposited as ink dots on the treated surface of the surface-treated recording medium obtained in step 1, thereby forming an image. Any type of inkjet recording device can be used, such as a thermal type or a piezo type.

[0065] The present invention may also include the following aspects: <1> A treatment liquid for inkjet recording, comprising a polyoxyethylene ether compound (A) having an aromatic ring, a flocculant (B'), and water, wherein the content of the compound (A) is 3 mass % or more.

[0066] <2> The treatment liquid for inkjet recording according to <1>, wherein the flocculating agent (B′) is one or more compounds (B) selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids.

[0067] <3> The treatment liquid for inkjet recording according to <1> or <2>, wherein the treatment liquid for inkjet recording is a pretreatment liquid for inkjet recording.

[0068] <4> The treatment liquid for inkjet recording according to <2> or <3>, wherein the polyvalent metal ion constituting the polyvalent metal salt is at least one selected from the group consisting of a divalent metal ion and a trivalent metal ion.

[0069] <5> The treatment liquid for inkjet recording according to any one of <2> to <4>, wherein the polyvalent amine is a polymer containing a structural unit derived from a polymerizable monomer having at least one amino group.

[0070] <6> The treatment liquid for inkjet recording according to any one of <2> to <5>, wherein the organic acid is a hydroxycarboxylic acid.

[0071] <7> The treatment liquid for inkjet recording according to any one of <2> to <6>, wherein a mass ratio of the content of the compound (B) to the content of the compound (A) in the treatment liquid for inkjet recording [compound (B) / compound (A)] is less than 15.

[0072] <8> The treatment liquid for inkjet recording according to any one of <2> to <7>, wherein the compound (B) is at least one selected from the group consisting of magnesium nitrate, calcium nitrate, and aluminum nitrate.

[0073] <9> The treatment liquid for inkjet recording according to any one of <1> to <8>, wherein the compound (A) has an HLB value of 10 or more and 20 or less, as determined by the Griffin method.

[0074] <10> The treatment liquid for inkjet recording according to any one of <1> to <9>, wherein the compound (A) has an HLB value of 11 or more and 14 or less, as determined by the Griffin method.

[0075] <11> The treatment liquid for inkjet recording according to any one of <1> to <10>, wherein the content of the compound (A) in the treatment liquid for inkjet recording is 3% by mass or more and 60% by mass or less.

[0076] <12> The treatment liquid for inkjet recording according to any one of <2> to <11>, wherein the content of the compound (B) in the treatment liquid for inkjet recording is 1% by mass or more and 40% by mass or less.

[0077] <13> The treatment liquid for inkjet recording according to any one of <2> to <12>, wherein the content of the compound (B) in the treatment liquid for inkjet recording is 1% by mass or more and 40% by mass or less.

[0078] <14> The pretreatment liquid for inkjet recording according to any one of <1> to <13>, further comprising a pH adjuster in an amount of 0.1% by mass to 1% by mass based on the inkjet recording treatment liquid.

[0079] <15> A treatment liquid for inkjet recording, comprising a polyoxyethylene ether compound (A) having an aromatic ring, a flocculant (B'), and water, wherein the compound (A) is a polyoxyethylene phenyl ether, the flocculant (B') is one or more compounds (B) selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids, the polyvalent metal salt is an inorganic acid salt of a divalent or trivalent metal, the polyvalent amine is a polymer containing a structural unit derived from a polymerizable monomer having at least one amino group, the organic acid is a hydroxycarboxylic acid, the content of the compound (A) is 3% by mass or more, the content of the compound (B) is 1% by mass or more and 40% by mass or less, and the mass ratio of the content of the compound (B) to the content of the compound (A) [compound (B) / compound (A)] is less than 15.

[0080] <16> The treatment liquid for inkjet recording according to <15>, wherein the compound (A) is a polyoxyethylene phenyl ether having an HLB of 10 to 20, the flocculant (B') is one or more compounds (B) selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids, the polyvalent metal salt is a nitrate salt of a divalent or trivalent metal, the polyvalent amine is a diallyl quaternized ammonium salt polymer having a weight average molecular weight of 5,000 to 50,000, the organic acid is a hydroxy polycarboxylic acid, the content of the compound (A) is 3% by mass to 60% by mass, the content of the compound (B) is 5% by mass to 25% by mass, and the mass ratio [compound (B) / compound (A)] is 0.1 to 8.

[0081] <17> The compound (A) is one or more compounds selected from the group consisting of polyoxyethylene phenyl ether and polyoxyethylene distyrenated phenyl ether having an HLB of 10 or more and 20 or less, the flocculant (B') is one or more compounds (B) selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids, the polyvalent metal salt is one or more compounds selected from the group consisting of magnesium nitrate, calcium nitrate, and aluminum nitrate, the polyvalent amine is one or more compounds selected from polydiallyldimethylammonium chloride and dimethylamine / epichlorohydrin copolymers having a weight average molecular weight of 5,000 or more and 50,000 or less, the organic acid is one or more compounds selected from citric acid, tartaric acid, and lactic acid, the content of the compound (A) is 5% by mass or more and 50% by mass or less, the content of the compound (B) is 10% by mass or more and 20% by mass or less, The treatment liquid for inkjet recording according to <15> or <16>, wherein the mass ratio [compound (B) / compound (A)] is 0.3 or more and 4 or less.

[0082] <18> The treatment liquid for inkjet recording according to any one of <15> to <17>, which is a pretreatment liquid for inkjet recording.

[0083] <19> The treatment liquid for inkjet recording according to any one of <15> to <18>, wherein the compound (A) is at least one selected from the group consisting of polyoxyethylene phenyl ether and polyoxyethylene distyrenated phenyl ether, each having an HLB of 11 to 15.

[0084] <20> The treatment liquid for inkjet recording according to any one of <15> to <19>, wherein the aggregating agent (B′) is a polyvalent metal salt, and the polyvalent metal salt is at least one selected from the group consisting of magnesium nitrate and calcium nitrate.

[0085] <21> The treatment liquid for inkjet recording according to any one of <15> to <20>, wherein the content of the compound (A) is 15% by mass or more and 45% by mass or less.

[0086] <22> The treatment liquid for inkjet recording according to any one of <15> to <21>, wherein the mass ratio [compound (B) / compound (A)] is 0.3 or more and 1 or less.

[0087] <23> The treatment liquid for inkjet recording according to any one of <1> to <122>, which is for treating a recording medium used in inkjet recording.

[0088] <24> An ink set for inkjet recording, comprising the treatment liquid for inkjet recording according to any one of <1> to <23> above, and an ink containing a colorant and water.

[0089] <25> The ink set for inkjet recording according to <24>, wherein the inks are aqueous pigment inks.

[0090] <26> A surface-treated recording medium that has been treated with the treatment liquid for inkjet recording according to any one of <1> to <23>.

[0091] <27> An inkjet recording method using the treatment liquid for inkjet recording according to any one of <1> to <23>, comprising the following steps 1 and 2: Step 1: applying the treatment liquid for inkjet recording to a recording medium, and then heating and drying the recording medium to obtain a surface-treated recording medium; and Step 2: forming an image on the treated surface of the surface-treated recording medium obtained in Step 1 by an inkjet recording method using an ink containing a colorant and water.

[0092] <28> Use of a composition as a pretreatment liquid for inkjet recording, the composition comprising (A) a polyoxyethylene ether compound having an aromatic ring, (B) one or more compounds selected from the group consisting of a polyvalent metal salt, a polyvalent amine, and an organic acid, and water, wherein the content of the compound (A) is 3 mass % or more.

[0093] <29> Use of the composition as a pretreatment liquid for inkjet recording according to <28>, wherein the compound (B) is one or more selected from the group consisting of magnesium nitrate, calcium nitrate, and aluminum nitrate; the mass ratio of the content of the compound (B) to the content of the compound (A) in the composition [compound (B) / compound (A)] is 0.3 or more and less than 15; the HLB value of the compound (A) measured by the Griffin method is 10 or more and 14 or less; the content of the compound (A) in the composition is 5% by mass or more and 60% by mass or less; the content of the compound (B) in the composition is 1% by mass or more and 40% by mass or less; and the composition further contains triethanolamine in an amount of 0.1% by mass or more and 1% by mass or less.

[0094] <30> Use of the composition as a pretreatment liquid for inkjet recording according to <28> or <29>, wherein the composition is used together with an aqueous pigment ink.

[0095] In the following Production Examples, Examples and Comparative Examples, "parts" means "parts by mass" unless otherwise specified. Various physical properties were measured or calculated by the following methods.

[0096] (1) Number-average molecular weight of pigment-dispersed resin: This was determined by gel permeation chromatography. The measurement sample was prepared by mixing 0.1 g of resin with 10 mL of the eluent described below in a glass vial, stirring the mixture with a magnetic stirrer at 25°C for 10 hours, and filtering the mixture through a syringe filter "DISMIC-13HP" (PTFE, 0.2 μm, manufactured by Advantec Co., Ltd.). The measurement conditions are shown below. GPC apparatus: "HLC-8320GPC" manufactured by Tosoh Corporation Column: "TSKgel SuperAWM-H", "TSKgel SuperAW3000", "TSKgel guard column Super AW-H" manufactured by Tosoh Corporation Eluent: N,N-dimethylformamide dissolved with phosphoric acid and lithium bromide to concentrations of 60 mmol / L and 50 mmol / L, respectively Flow rate: 0.5 mL / min Standard substance: monodisperse polystyrene kit with known molecular weight manufactured by Tosoh Corporation "PStQuick b (F-550, F-80, F-10, F-1, a-1000)", "PStQuick c (F-288, F-40, F-4, A-5000, A-500)"

[0097] (2) Acid Value of Pigment Dispersion Resin The acid value of the pigment dispersion resin was measured by dissolving the resin in a titration solvent (toluene:acetone=2:1 (volume ratio)) prepared by mixing toluene and acetone in an automatic potentiometric titrator (Kyoto Electronics Manufacturing Co., Ltd., electric burette, model number: APB-610), and titrating the resin with a 0.1 N potassium hydroxide / ethanol solution by potentiometric titration, with the inflection point on the titration curve being the endpoint. The acid value (mg KOH / g) was calculated from the titration amount of the potassium hydroxide solution up to the endpoint.

[0098] (3) Solids Concentration of Pigment Dispersion and Wax Dispersion A 30 mL polypropylene container (φ: 40 mm, height: 30 mm) was precisely weighed, and approximately 10.0 g of sodium sulfate (reagent manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) that had been brought to a constant weight in a desiccator was weighed into the container, and the mass of the sodium sulfate was precisely weighed. Approximately 1 g of pigment dispersion or wax dispersion was added and mixed thereto, and the mass of the pigment dispersion or wax dispersion was precisely weighed. Next, the mixture was maintained at 105°C for 2 hours to remove volatiles, and the mixture was left in the desiccator for an additional 15 minutes, after which the mass of the entire container was precisely weighed. The mass of the pigment dispersion or wax dispersion residue after volatiles removal was calculated by subtracting the precisely weighed mass of the container and the precisely weighed mass of the sodium sulfate from the precisely weighed mass of the entire container. The mass of the residue of the pigment dispersion or wax dispersion after devolatilization was divided by the precisely weighed mass of the pigment dispersion or wax dispersion before devolatilization to obtain the solids concentration (mass %).

[0099] (4) Melting Point of Wax The melting point of the wax was measured using an apparatus conforming to JIS K 0064:1992. Specifically, a sample obtained by drying a wax dispersion was used, and the sample was heated to 200°C using a differential scanning calorimeter "DSC Q20" (manufactured by TA Instruments Co., Ltd.) and then cooled from that temperature to 0°C at a temperature decrease rate of 10°C / min. The sample was then heated at a temperature increase rate of 10°C / min, and the calorific value was measured up to 200°C. Among the observed heat of fusion peaks, the temperature of the peak with the largest peak area was determined as the maximum peak temperature of melting, and this peak temperature was determined as the melting point of the wax.

[0100] (5) Average particle size of pigment dispersion The particle size was measured by dynamic light scattering using a laser particle analysis system "ELS-8000" (manufactured by Otsuka Electronics Co., Ltd.), and calculated by cumulant analysis. The measurement conditions were a temperature of 25°C, an angle between the incident light and the detector of 90°, and 100 cumulative measurements, and the refractive index of water (1.333) was input as the refractive index of the dispersion solvent. For the measurement sample, the pigment dispersion was weighed into a screw tube (manufactured by Maruemu Co., Ltd., No. 5), and the solids concentration was 2 × 10 -4 Water was added to the mixture so that the concentration became 5% by mass, and the mixture was stirred at 25° C. for 1 hour using a magnetic stirrer.

[0101] (6) Viscosity of Treatment Liquid The viscosity of the treatment liquid at 25° C. was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., model number: TV-25, using a standard cone rotor 1°34′×R24, rotation speed 50 rpm).

[0102] (7) pH of Treatment Solution The pH at 20° C. was measured using a tabletop pH meter “F-71” (manufactured by Horiba Ltd.) equipped with a pH electrode “6337-10D” (manufactured by Horiba Ltd.).

[0103] Production Example 1-1 (Production of Pigment Dispersion Resin (1)) A monomer mixture was prepared by mixing 31 parts of acrylic acid (reagent manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) and 69 parts of styrene (reagent manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.). In a reaction vessel, 10 parts of methyl ethyl ketone (hereinafter also referred to as "MEK") (reagent manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 0.2 parts of a polymerization chain transfer agent (2-mercaptoethanol) (reagent manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), and 10% by mass of the monomer mixture were placed and mixed, and the atmosphere was thoroughly purged with nitrogen gas. Separately, a mixture of the remainder of the monomer mixture (90% by mass of the monomer solution), 0.13 parts of the polymerization chain transfer agent, 30 parts of MEK, and 1.1 parts of a radical polymerization initiator (2,2'-azobis(2,4-dimethylvaleronitrile), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name "V-65") was placed in a dropping funnel, and the monomer mixture in the reaction vessel was heated to 65°C with stirring under a nitrogen atmosphere, and the mixture in the dropping funnel was added dropwise over 3 hours. After 2 hours at 65°C from the end of the dropping, a solution in which 0.1 parts of the polymerization initiator was dissolved in 2 parts of MEK was added, and the mixture was further aged at 65°C for 2 hours and at 70°C for 2 hours, followed by drying under reduced pressure to obtain an acrylic acid / styrene copolymer (number average molecular weight: 19,000, acid value: 240 mgKOH / g) as pigment dispersion resin (1) (hereinafter also referred to as "pigment dispersion resin (1)").

[0104] Production Example 2-C1 (Production of Inkjet Recording Cyan Ink I-C1) 100 parts of the pigment dispersion resin (1) obtained in Production Example 1-1 and 78.6 parts of MEK were mixed, and 41.2 parts of a 5N aqueous sodium hydroxide solution (for volumetric analysis, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., sodium hydroxide content: 16.9% by mass) was added as a neutralizing agent to neutralize the mixture (degree of neutralization: 40 mol%). Next, 800 parts of ion-exchanged water was added, and 100 parts of a cyan pigment (C.I. Pigment Blue 15:3, manufactured by DIC Corporation, trade name "TGR-SD") was added. The mixture was stirred for 60 minutes at 20°C using a Disper mixer (manufactured by Asada Iron Works Co., Ltd., trade name "Ultra Disper") with a Disper blade rotating at 7,000 rpm to obtain a pigment mixture. The resulting pigment mixture was subjected to 10 passes of dispersion treatment at a pressure of 200 MPa using a Microfluidizer (trade name, manufactured by Microfluidics Corporation) to obtain a cyan pigment dispersion. 250 parts of ion-exchanged water was added to the resulting cyan pigment dispersion and stirred. After completely removing the MEK at 60°C under reduced pressure, a portion of the water was removed, and then 35.7 parts of trimethylolpropane polyglycidyl ether (trade name "Denacol EX-321", manufactured by Nagase ChemteX Corporation, epoxy equivalent: 140) was added as a crosslinking agent. The mixture was sealed and heated at 70°C for 5 hours while stirring with a stirrer. The mixture was then cooled to room temperature, and ion-exchanged water was added to obtain a solids concentration of 24% by mass. The mixture was then filtered through a 5 μm pore size filter (acetyl cellulose membrane, outer diameter: 2.5 cm, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to obtain a cyan pigment dispersion (crosslinking rate 60 mol%, average particle size: 102 nm).50 parts of the obtained cyan pigment dispersion, 2.9 parts of a polyethylene wax dispersion (manufactured by Toho Chemical Industry Co., Ltd., trade name "Hitec E-6500", ion type: nonionic, wax melting point: 140°C, solid content concentration: 35% by mass), 19 parts of 1,2-propanediol (reagent manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.), 8 parts of ethylene glycol monobutyl ether (reagent manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.), and 2,4,7,9-tetramethyl-5-decyne-4,7-diol (Air Products and The resulting mixture was mixed with 0.5 parts of a cellulose acetate solution (trade name "Surfynol 104" manufactured by Fujifilm Chemicals Co., Ltd.), and ion-exchanged water was added so that the total amount became 100 parts. The mixture was then filtered through a filter with a pore size of 5 μm (acetyl cellulose membrane, outer diameter: 2.5 cm, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to obtain a cyan ink for inkjet recording I-C1 (solids concentration: 13 mass %, pigment content: 5 mass %, pigment dispersing resin content: 7 mass %, wax content: 1 mass %).

[0105] Production Example 2-C2 (Production of cyan ink for inkjet recording I-C2) A cyan ink for inkjet recording I-C2 was obtained in the same procedure as in Production Example 2-C1, except that the water-soluble organic solvent was changed to 19 parts of dipropylene glycol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 8 parts of 1,2-hexanediol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 1,2-propanediol and ethylene glycol monobutyl ether.

[0106] Production Example 2-M1 (Production of Magenta Inkjet Recording Ink I-M1) A magenta ink for inkjet recording I-M1 was obtained in the same procedure as in Production Example 2-C1, except that a magenta pigment (C.I. Pigment Red 122, manufactured by DIC Corporation, product name "FASTOGEN Super Magenta RGT") was used instead of the cyan pigment.

[0107] Production Example 2-M2 (Production of magenta ink for inkjet recording I-M2) A magenta ink for inkjet recording I-M2 was obtained in the same procedure as in Production Example 2-C2, except that a magenta pigment (C.I. Pigment Red 122, manufactured by DIC Corporation, product name "FASTOGEN Super Magenta RGT") was used instead of the cyan pigment.

[0108] Preparation Example 1 (Preparation of Treatment Solution 1) The components of the treatment solution were added to a container equipped with a stirrer in the following formulation, mixed at 25°C for 1 hour, and then filtered using a 25 mL needleless syringe (manufactured by Terumo Corporation) equipped with a 5 μm pore size filter (acetyl cellulose membrane, outer diameter: 2.5 cm, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to obtain treatment solution 1. The viscosity of treatment solution 1 at 25°C was 5.6 mPa·s and the pH at 20°C was 5.1. [Composition of Treatment Solution 1] Polyoxyethylene phenyl ether (EO addition moles: 5, HLB value: 14) (manufactured by Aoki Oil & Fat Industries Co., Ltd., trade name "Brawnon PH-5") 20.0 parts Magnesium nitrate hexahydrate (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) 25.9 parts Ion-exchanged water 53.6 parts Triethanolamine (manufactured by Nippon Shokubai Co., Ltd.) 0.5 parts

[0109] Preparation Examples 2 to 12 and Comparative Preparation Examples 1 to 3 (Preparation of Treatment Liquids 2 to 12 and C1 to C3) Treatment liquids 2 to 12 and C1 to C3 were prepared in the same manner as in Preparation Example 1, except that the formulation of the treatment liquid was changed according to Table 1. The components of the treatment liquid other than the components used in Preparation Example 1 are shown below. [Polyoxyethylene ether compound (A) having an aromatic ring] Polyoxyethylene distyrenated phenyl ether (manufactured by Kao Corporation, trade name "Emulgen A-60", HLB value: 12.6, active content 100%) Polyoxyethylene styrenated phenyl ether (EO addition mole number: 9, HLB value: 11.4) (manufactured by Aoki Oil & Fat Industries Co., Ltd., trade name "Brawnon DSP-9", active content 100%) Diethylene glycol monobenzyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name "Benzyl Diglycol", HLB value: 10.7, active content 100%) Polyoxyethylene distyrenated phenyl ether (manufactured by Kao Corporation, trade name "Emulgen A-500", HLB value: 18, active content 100%) [Compounds (A') other than polyoxyethylene ether compound (A) having an aromatic ring] 1,4-cyclohexanedimethanol (manufactured by Eastman Chemical Co.)・Polyoxyethylene alkyl ether (manufactured by Kao Corporation, trade name "Emulgen 1108", HLB value: 13.5, active ingredient: 100%) [Compound (B)] [Polyvalent metal salts] ・Calcium nitrate tetrahydrate (manufactured by Tokyo Chemical Industry Co., Ltd., reagent) ・Aluminum nitrate nonahydrate (manufactured by Tokyo Chemical Industry Co., Ltd., reagent) [Polyvalent amines] ・PAS-H-1L (aqueous solution of polydiallyldimethylammonium chloride (solid content: 28% by mass), manufactured by Nittobo Medical Co., Ltd., trade name, weight average molecular weight: 8,500 (catalog value)) ・Unisense KHE-107L (aqueous solution of dimethylamine / epichlorohydrin copolymer (solid content: 52% by mass), manufactured by Senka Corporation, trade name, molecular weight converted to PEG by GPC: less than 20,000 (catalog value)) [Organic acids] ・40% by mass ammonium lactate aqueous solution (aqueous solution with active ingredient: 40% by mass, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0110] Example 1 (Step 1) Using a wireless bar coater "A-Bar" (manufactured by Mitsui Electric Seiki Co., Ltd., model: OSP-1.5, pitch: 0.08 mm, depth: 4 μm, film thickness: 1.5 μm / wet), a coated paper "OK ​​Topcoat+" (manufactured by Oji Paper Co., Ltd., basis weight: 127.9 g / m) was applied as a low-permeability recording medium. ２ , Pure water absorption amount at contact time of 100 msec: 4.9 g / m ２ Treatment liquid 1 was uniformly applied to the substrate. The substrate was left to stand in an environment of 25°C and 50% RH for 10 minutes to dry at room temperature, and then heated and dried for 60 seconds in a thermostatic chamber heated to 100°C. The amount of treatment liquid 1 applied was 1.6±0.3 g / m ２ It was made to be like this.

[0111] (Step 2) On the treated surface of the surface-treated recording medium obtained in step 1, an image was formed by inkjet recording using the cyan ink for inkjet recording I-C1 and the magenta ink for inkjet recording I-M1 according to the methods (1) and (2) below, and the resulting prints were evaluated. The results are shown in Table 1.

[0112] Examples 2 to 12 and Comparative Examples 1 to 3 Surface-treated recording media were obtained in the same manner as in Example 1, except that in step 1, treatment liquid 1 was replaced with each of the treatment liquids shown in Table 1. Thereafter, the same operations as in step 2 of Example 1 were carried out, and images were formed by inkjet recording on the treated surface of the surface-treated recording medium obtained in step 1 using the inkjet recording cyan ink I-C1 and the inkjet recording magenta ink I-M1 according to the methods shown in (1) and (2) below, and the resulting prints were evaluated. The results are shown in Table 1.

[0113] An image was formed by inkjet recording in the same manner as in Example 1, except that the inkjet cyan ink I-C2 and the inkjet magenta ink I-M2 were used instead of the inkjet cyan ink I-C1 and the inkjet magenta ink I-M1 in step 2, and the resulting print was evaluated. The results are shown in Table 1.

[0114] <Evaluation> (1) Evaluation of dot expandability Images were created and evaluated by the following inkjet recording method using a cyan ink for inkjet recording on each of the surface-treated recording media obtained in step 1 of the Examples and Comparative Examples. In addition, images were also created and evaluated by the following inkjet recording method using a cyan ink for inkjet recording on each of the recording media after room temperature drying in step 1 of the Examples and Comparative Examples (not subjected to heat drying).

[0115] (Printing by Inkjet Recording Method) In an environment of a temperature of 25±1° C. and a relative humidity of 30±5%, a printing evaluation device (manufactured by Tritec Corporation) equipped with an inkjet head "KJ4B-HD06MHG-STDV" (manufactured by Kyocera Corporation, piezo type) was filled with cyan ink for inkjet recording. The head voltage was set to 26 V, the frequency to 20 kHz, the ejection liquid amount to 12 pL, the head temperature to 32° C., the resolution to 600 dpi, and the negative pressure to -4.0 kPa, and the surface-treated recording medium or the recording medium after drying at room temperature in step 1 was fixed to a conveying table under reduced pressure so that the longitudinal direction of the surface-treated recording medium or the recording medium after drying at room temperature in step 1 was the same as the conveying direction. A print command was transferred to the print evaluation device, an image with a cyan ink duty of 2% was printed, and the ink dot diameter was measured using a handy image evaluation system "PIAS (registered trademark)-II" (manufactured by Quality Engineering Associates (QEA)) under conditions of a threshold of 50%, a minimum dot diameter of 10 μm, and a maximum dot diameter of 100 μm. The results are shown in Table 1. The larger the dot diameter, the better the dot expandability and the better the image quality. The evaluation criteria are as follows. A rating of C means there is no practical problem. (Evaluation criteria) A: Dot diameter is 60 μm or more B: Dot diameter is 58 μm or more and less than 60 μm C: Dot diameter is 55 μm or more and less than 58 μm D: Dot diameter is less than 55 μm

[0116] (2) Evaluation of Image Uniformity Images were formed on each of the surface-treated recording media obtained in step 1 of the Examples and Comparative Examples by the following inkjet recording method using the cyan ink for inkjet recording and the magenta ink for inkjet recording.

[0117] (Printing by Inkjet Recording Method) In an environment of a temperature of 25±1° C. and a relative humidity of 30±5%, a printing evaluation device (manufactured by Tritec Corporation) equipped with an inkjet head "KJ4B-HD06MHG-STDV" (manufactured by Kyocera Corporation, piezo type) was filled with a cyan ink for inkjet recording and a magenta ink for inkjet recording. The head voltage was set to 26 V, the frequency to 20 kHz, the ejection liquid amount to 12 pL, the head temperature to 32° C., the resolution to 600 dpi, and the negative pressure to -4.0 kPa, and the surface-treated recording medium was fixed to a conveyance table under reduced pressure so that the longitudinal direction of the surface-treated recording medium was the same as the conveyance direction. A print command was transferred to the print evaluation device, and an image was printed using inkjet cyan ink and inkjet magenta ink at a duty of 60% each, for a total duty of 120%, and the image uniformity of the printed image was evaluated using a handy image evaluation system "PIAS (registered trademark)-II" (manufactured by Quality Engineering Associates (QEA)). * The graininess value was measured. The results are shown in Table 1. * The smaller the graininess value, the more suppressed the color mixing between dots is, and the better the image quality. The evaluation criteria are shown below. If the evaluation is C, there is no problem in practical use. (Evaluation criteria) A: L * Grainness value is less than 1.6 B:L * Grainness value is 1.6 or more and less than 2.3 C:L * Grainness value is 2.3 or more and less than 3.0 D:L * Grainness value is 3.0 or more

[0118]

[0119] From Table 1, it can be seen that, compared to Comparative Examples 1 to 3, in printing using a recording medium with low permeability, Examples 1 to 13 can obtain high-quality printed matter that combines good dot expandability and image uniformity, even when a heat drying process is performed after application of the treatment liquid.

[0120] According to the present invention, it is possible to provide a treatment liquid for inkjet recording, an ink set for inkjet recording, a surface-treated recording medium, and an inkjet recording method that are capable of obtaining high-quality printed matter that combines good dot expandability and excellent image uniformity, even when a heat drying step is performed after the treatment liquid is applied to a low-permeability recording medium.

Claims

1. An inkjet recording treatment liquid containing a polyoxyethylene ether compound (A) having an aromatic ring, a flocculant (B'), and water, wherein the content of the compound (A) is 3% by mass or more.

2. The inkjet recording treatment liquid according to claim 1, wherein the flocculant (B') is at least one compound (B) selected from the group consisting of polyvalent metal salts, polyvalent amines, and organic acids.

3. The inkjet recording treatment liquid according to claim 2, wherein the polyvalent metal ions constituting the polyvalent metal salt are divalent metal ions.

4. The inkjet recording treatment liquid according to claim 2, wherein the polyvalent amine is a polymer containing a structural unit derived from a polymerizable monomer having at least one amino group.

5. The inkjet recording treatment liquid according to claim 2, wherein the mass ratio [compound (B) / compound (A)] of the content of the compound (B) to the content of the compound (A) in the inkjet recording treatment liquid is less than 15.

6. The inkjet recording treatment liquid according to claim 2, wherein the compound (B) is a polyvalent metal salt.

7. The inkjet recording treatment liquid according to claim 2, wherein the HLB value of the compound (A) is 10 or more and 20 or less.

8. The inkjet recording treatment liquid according to claim 2, wherein the content of the compound (A) in the treatment liquid is 5% by mass or more and 60% by mass or less.

9. The inkjet recording treatment liquid according to claim 2, wherein the content of the compound (B) in the treatment liquid is 1% by mass or more and 40% by mass or less.

10. The inkjet recording treatment liquid according to claim 2, which is for treating a recording medium used in inkjet recording.

11. The inkjet recording treatment liquid according to claim 2, wherein the treatment liquid is a pretreatment liquid for inkjet recording.

12. An inkjet recording ink set including the inkjet recording treatment liquid according to any one of claims 1 to 11, and an ink containing a coloring material and water.

13. A surface-treated recording medium treated with the treatment liquid according to any one of claims 1 to 11.

14. An inkjet recording method using the inkjet recording treatment liquid according to any one of claims 1 to 11 and including the following steps 1 and 2. Step 1: A step of applying the inkjet recording treatment liquid to a recording medium and then heating and drying it to obtain a surface-treated recording medium. Step 2: A step of forming an image by an inkjet recording method using an ink containing a coloring material and water on the treated surface of the surface-treated recording medium obtained in Step 1.

15. Use of a composition containing a polyoxyethylene ether compound (A) having an aromatic ring, one or more compounds (B) selected from the group consisting of a polyvalent metal salt, a polyvalent amine, and an organic acid, and water, wherein the content of the compound (A) is 3% by mass or more, as a pretreatment liquid for inkjet recording.

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