Aqueous dispersion, aqueous ink, recording medium, and method for producing aqueous dispersion

Abstract

Provided is an aqueous dispersion containing a vinyl chloride-based polymer, a water-dispersible polymer, and solid particles. The weight average molecular weight of the water-dispersible polymer is 5000-50000. The median diameter of the solid particles as determined through dynamic light scattering is less than 1 μm. The solid particles each have a hydrophilic functional group on the surface thereof. The aqueous dispersion contains 10-40 parts by mass of the vinyl chloride-based polymer with respect to 100 parts by mass of the total of the vinyl chloride-based polymer, the water-dispersible polymer, and the solid particles. The aqueous dispersion contains 5-30 parts by mass of the water-dispersible polymer with respect to 100 parts by mass of the total of the vinyl chloride-based polymer, the water-dispersible polymer, and the solid particles. The aqueous dispersion contains 50-65 parts by mass of the solid particles with respect to 100 parts by mass of the total of the vinyl chloride-based polymer, the water-dispersible polymer, and the solid particles.

Description

Aqueous dispersion, aqueous ink, recording medium, and method for producing the aqueous dispersion

[0001] The present invention relates to aqueous dispersions, aqueous inks, recording media, and methods for producing aqueous dispersions.

[0002] Patent Documents 1 to 3 disclose synthetic resin emulsions containing a copolymer of a vinyl chloride monomer and another polymerizable monomer as a main component. Patent Documents 4 and 5 disclose vinyl chloride resin emulsions obtained by polymerizing vinyl chloride monomer in the presence of a specific type of oligomer. Patent Document 6 discloses a coating composition containing silica microparticles, a surfactant, and a resin emulsion. Patent Document 7 discloses an aqueous dispersion obtained by emulsion polymerization of an ethylenically unsaturated monomer (particularly a carboxyl group-containing monomer) using an aqueous resin composition and water-dispersible inorganic particles as emulsion stabilizers. Patent Document 8 discloses glossy inkjet recording paper for oil-based pigment inks having a cast coat layer obtained by mixing a vinyl chloride resin with spherical colloidal silica. Patent Document 9 discloses polyvinyl chloride resin particles obtained by polymerizing vinyl chloride monomer in the presence of colloidal silica. (Prior art documents) (Patent documents) (Patent document 1) JP 49-112990 A (Patent document 2) JP 51-74081 A (Patent document 3) JP 60-15471 A (Patent document 4) WO 2010 / 140647 (Patent document 5) WO 2020 / 166660 (Patent document 6) JP 2012-241181 A (Patent document 7) JP 2008-239779 A (Patent document 8) JP 2020-026042 A (Patent document 9) JP 2017-095587 A General disclosure

[0003] In a first aspect of the present invention, an aqueous dispersion is provided. The aqueous dispersion includes, for example, a vinyl chloride polymer. The aqueous dispersion includes, for example, a water-dispersed polymer. The aqueous dispersion includes, for example, solid particles. The weight-average molecular weight of the water-dispersed polymer is, for example, 5,000 to 50,000. The median diameter of the solid particles, as measured by dynamic light scattering, is, for example, less than 1 μm. The solid particles have, for example, hydrophilic functional groups on their surfaces. The aqueous dispersion includes, for example, 10 to 40 parts by mass of the vinyl chloride polymer relative to 100 parts by mass of the vinyl chloride polymer, the water-dispersed polymer, and the solid particles. The aqueous dispersion includes, for example, 5 to 30 parts by mass of the water-dispersed polymer relative to 100 parts by mass of the vinyl chloride polymer, the water-dispersed polymer, and the solid particles. The aqueous dispersion includes, for example, 50 to 65 parts by mass of the solid particles relative to 100 parts by mass of the vinyl chloride polymer, the water-dispersed polymer, and the solid particles.

[0004] In any of the above aqueous dispersions, the water-dispersed polymer may have at least one of a carboxy group and a urethane group. In any of the above aqueous dispersions, the water-dispersed polymer may include at least one of a polymer of an ethylenically unsaturated group-containing monomer and a urethane-based polymer. In any of the above aqueous dispersions, the water-dispersed polymer may include at least one of an acrylic acid ester oligomer, a styrene-acrylic acid ester oligomer, and a polycarbonate-based urethane oligomer.

[0005] In any of the above aqueous dispersions, the vinyl chloride polymer and the water-dispersed polymer may form a core-shell structure in which the water-dispersed polymer covers the vinyl chloride polymer. In any of the above aqueous dispersions, the solid particles may be bonded to the water-dispersed polymer forming the core-shell structure by intermolecular interactions.

[0006] In any of the above aqueous dispersions, (i) the content of the surfactant having a molecular weight of 1,000 or less in the aqueous dispersion is 100 g / m ３In any of the above aqueous dispersions, (ii) the ratio by mass of the surfactant having a molecular weight of 1,000 or less to the mass of the vinyl chloride polymer may be less than 0.001% by mass.

[0007] In any of the above aqueous dispersions, the ratio of the mass of the solid content of the aqueous dispersion to the mass of the aqueous dispersion may be 10 mass % or more and 50 mass % or less.

[0008] In any of the above aqueous dispersions, the solid particles may contain colloidal silica having a median diameter of 6 nm or more and 100 nm or less as measured by dynamic light scattering.

[0009] In a second aspect of the present invention, an aqueous dispersion is provided. The aqueous dispersion is obtained, for example, by polymerizing vinyl chloride monomer in a reaction solution. The reaction solution is obtained, for example, by mixing vinyl chloride monomer, a water-dispersed polymer, solid particles, and an aqueous solvent. The weight-average molecular weight of the water-dispersed polymer is, for example, 5,000 to 50,000. The median diameter of the solid particles measured by dynamic light scattering is, for example, less than 1 μm. The solid particles have, for example, hydrophilic functional groups on their surfaces. In the aqueous dispersion, the reaction solution contains, for example, 10 to 40 parts by mass of vinyl chloride monomer per 100 parts by mass of the vinyl chloride monomer, the water-dispersed polymer, and the solid particles. In the aqueous dispersion, the reaction solution contains, for example, 5 to 30 parts by mass of the water-dispersed polymer per 100 parts by mass of the vinyl chloride monomer, the water-dispersed polymer, and the solid particles. In the aqueous dispersion, the reaction liquid contains, for example, 50 parts by mass or more and 65 parts by mass or less of solid particles per 100 parts by mass of the total of the vinyl chloride monomer, the water-dispersible polymer, and the solid particles.

[0010] In any of the above aqueous dispersions, (i) the concentration of the surfactant having a molecular weight of 1,000 or less in the aqueous dispersion is 100 g / m ３ In any of the above aqueous dispersions, (ii) the ratio by mass of the surfactant having a molecular weight of 1,000 or less to the mass of the vinyl chloride monomer may be less than 0.001% by mass.

[0011] In a third aspect of the present invention, there is provided an aqueous ink, which comprises, for example, any of the aqueous dispersions according to the first aspect or any of the aqueous dispersions according to the second aspect.

[0012] In a fourth aspect of the present invention, there is provided a recording medium, which comprises, for example, a composition derived from any of the aqueous dispersions according to the first aspect or a composition derived from any of the aqueous dispersions according to the second aspect.

[0013] In a fifth aspect of the present invention, a recording medium is provided. The recording medium includes, for example, a substrate. The recording medium includes, for example, a recording layer disposed on at least one side of the substrate. In the recording medium, the recording layer includes, for example, a vinyl chloride polymer. In the recording medium, the recording layer includes, for example, a water-dispersible polymer. In the recording medium, the recording layer includes, for example, solid particles. The weight-average molecular weight of the water-dispersible polymer is, for example, 5,000 to 50,000. The median diameter of the solid particles measured by dynamic light scattering is, for example, less than 1 μm. The solid particles have, for example, hydrophilic functional groups on their surfaces. In the recording medium, the recording layer includes, for example, 10 to 40 parts by weight of the vinyl chloride polymer relative to a total of 100 parts by weight of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles. In the recording medium, the recording layer includes, for example, 5 to 30 parts by weight of the water-dispersible polymer relative to a total of 100 parts by weight of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles. In the above recording medium, the recording layer contains, for example, 50 to 65 parts by mass of solid particles per 100 parts by mass of the vinyl chloride polymer, water-dispersible polymer, and solid particles combined.

[0014] A sixth aspect of the present invention provides a method for producing an aqueous dispersion. The method includes, for example, a step of preparing a reaction solution by mixing vinyl chloride monomer, a water-dispersed polymer, solid particles, and an aqueous solvent. The method includes, for example, a step of polymerizing the vinyl chloride monomer in the presence of the water-dispersed polymer and the solid particles. In the method, the weight-average molecular weight of the water-dispersed polymer is, for example, 5,000 to 50,000. In the method, the median diameter of the solid particles measured by dynamic light scattering is, for example, less than 1 μm. The solid particles have, for example, hydrophilic functional groups on their surfaces. In the method, the reaction solution includes, for example, 10 to 40 parts by mass of vinyl chloride monomer per 100 parts by mass of the total of the vinyl chloride monomer, the water-dispersed polymer, and the solid particles. In the method, the reaction solution includes, for example, 5 to 30 parts by mass of the water-dispersed polymer per 100 parts by mass of the total of the vinyl chloride monomer, the water-dispersed polymer, and the solid particles. In the above method, the reaction liquid contains, for example, 50 parts by mass or more and 65 parts by mass or less of solid particles per 100 parts by mass of the total of the vinyl chloride monomer, the water-dispersible polymer, and the solid particles.

[0015] In the above method, the step of polymerizing vinyl chloride monomer comprises: (i) adjusting the concentration of the surfactant having a molecular weight of 1,000 or less in the reaction solution to 100 g / m ３ The method may include a step of polymerizing vinyl chloride monomer under the following conditions: (i) a surfactant having a molecular weight of 1,000 or less is polymerized under the following conditions: (ii) a surfactant having a molecular weight of 1,000 or less is polymerized ...

[0016] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also constitute inventions.

[0017] 1A and 1B schematically show an example of a recording medium 100 and a method for manufacturing the recording medium 100. 1C schematically show an example of a dispersoid 134 having a core-shell structure. 1D schematically show an example of a method for manufacturing a dispersion 130.

[0018] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention. Not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, the embodiments will be described with reference to the drawings. In the description of the drawings, the same reference numerals may be used to designate the same or similar parts, and redundant description may be omitted.

[0019] 1 is a schematic diagram of a recording medium 100 and an example of a method for manufacturing the same. In this embodiment, the recording medium 100 includes, for example, a substrate 110 and a recording layer 120.

[0020] In this embodiment, the recording medium 100 is used to record various types of information, such as characters, symbols, patterns, and figures. The information is recorded on the surface or inside the recording layer 120 of the recording medium 100 using a method such as printing, coating, or coating (sometimes simply referred to as coating). According to one embodiment, a receptor layer for fixing ink, paint, or the like is disposed on the surface of the recording layer 120. According to another embodiment, the recording layer 120 includes a receptor layer and another layer disposed on the receptor layer. Examples of the recording medium 100 include recording paper, labels, posters, wallpaper, and packaging materials. Examples of packaging materials include PET film, OPP film, and PP film.

[0021] (Outline of Substrate 110) In this embodiment, the substrate 110 supports, for example, the recording layer 120. Examples of materials constituting the substrate 110 include paper, fiber, leather, resin, metal, glass, cement, and wood. Examples of fibers include woven fabric, knitted fabric, and nonwoven fabric. The fiber may be natural fiber or synthetic fiber. Examples of the shape of the substrate 110 include a sheet or film, a plate, a column, or a block.

[0022] (Outline of recording layer 120) In this embodiment, the recording layer 120 is used to record various types of information such as characters, symbols, patterns, and figures. The recording layer 120 may be composed of a single layer or multiple layers. The recording layer 120 may include a receiving layer. The recording layer 120 may function as a receiving layer.

[0023] In this embodiment, the recording layer 120 is disposed on at least one of the surfaces of the substrate 110. In one embodiment, the substrate 110 and the recording layer 120 may be in contact with each other. In another embodiment, another material may be disposed between the substrate 110 and the recording layer 120.

[0024] In this embodiment, the recording layer 120 contains a composition derived from the dispersion 130. The recording layer 120 may have a receptor layer containing a composition derived from the dispersion 130.

[0025] (Method of Manufacturing Recording Layer 120) The recording layer 120 is manufactured, for example, by the following procedure. First, the substrate 110 and the dispersion liquid 130 are prepared. The details of the substrate 110 may be as described above.

[0026] In this embodiment, the dispersion 130 contains a vinyl chloride polymer (sometimes referred to as a vinyl chloride resin) and a water-dispersible polymer (sometimes referred to as a water-dispersible oligomer) having a weight-average molecular weight of 5,000 to 50,000. The dispersion 130 may contain, as a dispersoid, a core-shell structure constituted by the vinyl chloride polymer and the water-dispersible oligomer.

[0027] In this embodiment, the dispersion 130 contains solid particles having a median diameter (sometimes referred to as 50% particle diameter, D50, etc.) of less than 1 μm as determined by dynamic light scattering, as a stabilizer or aggregation inhibitor for dispersing the dispersoid in the dispersion medium. In dynamic light scattering, a particle size distribution is created based on the intensity of scattered light. Therefore, the particle size distribution initially obtained in dynamic light scattering is based on the scattered light intensity. A dispersion stabilized by solid particles is sometimes called a Pickering emulsion. Details of the dispersion 130 will be described later.

[0028] Next, a paint 140 containing the dispersion liquid 130 is prepared. For example, the paint 140 is obtained by mixing the dispersion liquid 130 with any type of solvent in any ratio. Details of the paint 140 will be described later.

[0029] Next, the coating material 140 is applied onto one surface of the substrate 110. The coating material 140 is applied onto one surface of the substrate 110 by a coating method such as a blade coater, an air knife coater, a curtain coater, a Mayer bar coater, a gravure coater, or a roll coater. The amount of coating material 140 applied is 3 to 25 g / m2 in terms of dry weight solid content. ２ This forms a paint layer 150 on one surface of the substrate 110.

[0030] Thereafter, the coating layer 150 is dried to produce the recording layer 120 containing the composition derived from the dispersion liquid 130. The drying temperature may be 50° C. or higher, and is preferably 100° C. or higher. In this way, the recording medium 100 including the substrate 110 and the recording layer 120 is produced.

[0031] (Composition of Dispersion 130) In this embodiment, the dispersion 130 includes, for example, a dispersion medium 132, a dispersoid 134, and a stabilizer 136. The dispersion 130 may be substantially free of an organic compound surfactant. The dispersion 130 may be substantially free of a cationic surfactant and / or an amphoteric surfactant. The dispersion 130 may be substantially free of a surfactant having a molecular weight of 1,000 or less. For example, (i) the content of the surfactant in the dispersion 130 is 100 g / m ３ (sometimes referred to as ppm) or less, or (ii) when the ratio of the mass of the surfactant to the mass of the vinyl chloride resin contained in the dispersion 130 is less than 0.001 mass%, it can be determined that the dispersion 130 is substantially free of the surfactant.

[0032] (Outline of Dispersion Medium 132) According to this embodiment, water or an aqueous solution of various substances is used as the dispersion medium 132. The dispersion medium 132 may contain a water-soluble organic solvent.

[0033] Examples of solutes in the aqueous solution used as the dispersion medium 132 include acrylic oligomers and urethane oligomers. The content of each solute in the dispersion medium 132 may be 0.5 wt % or more and less than 7.5 wt % of acrylic oligomer, or 0.5 wt % or more and 7.5 wt % or less of urethane oligomer.

[0034] Examples of water-soluble organic solvents include ethylene glycol monoether, diethylene glycol monoether, propylene glycol monoether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol, diethylene glycol, propylene glycol, glycerin, methanol, ethanol, isopropyl alcohol, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, acetone, ethyl acetate, diacetone alcohol, etc. The content of each water-soluble organic solvent in the dispersion medium 132 may be 0.1 wt % or more and 10 wt % or less, or 1 wt % or more and 5 wt % or less.

[0035] (Outline of the Dispersoid 134) In this embodiment, the dispersoid 134 includes, for example, the vinyl chloride resin described above and the water-dispersible oligomer described above. The vinyl chloride resin may be a homopolymer or a copolymer. Inside the dispersion medium 132, the water-dispersible oligomer is disposed, for example, so as to cover the vinyl chloride resin. The water-dispersible oligomer is disposed so as to surround the periphery of the polymer, thereby forming a particulate or colloidal composition. The dispersoid 134 may include a core-shell structure constituted by the vinyl chloride resin and the water-dispersible oligomer.

[0036] The core-shell structure is composed of, for example, at least a portion of the vinyl chloride resin contained in the dispersion 130 and at least a portion of the water-dispersible oligomer contained in the dispersion 130. The core-shell structure has, for example, a structure in which a shell made of the water-dispersible oligomer is disposed around a core made of the vinyl chloride resin.

[0037] In the core-shell structure according to this embodiment, the median diameter (sometimes referred to as 50% particle diameter, D50, etc.) measured by dynamic light scattering may be 10 to 600 nm. The median diameter measured by dynamic light scattering may be 20 to 500 nm, preferably 20 to 120 nm, and more preferably 20 to 100 nm. The dispersoid 134 having the core-shell structure described above will be described in detail later.

[0038] (Vinyl chloride resin) In the present embodiment, the vinyl chloride resin may be (i) a homopolymer of a vinyl chloride monomer, or (ii) a copolymer of a vinyl chloride monomer and one or more ethylenically unsaturated group-containing monomers. The ethylenically unsaturated group-containing monomer may be any compound copolymerizable with the vinyl chloride monomer, and the details thereof are not particularly limited.

[0039] Examples of the ethylenically unsaturated group-containing monomer include ethylene, propylene, vinylidene chloride, vinyl carboxylate monomers, aromatic vinyl monomers, conjugated diene monomers, ethylenically unsaturated monocarboxylic acid esters, ethylenically unsaturated polycarboxylic acid esters, ethylenically unsaturated monocarboxylic acids, ethylenically unsaturated dicarboxylic acids, epoxy group-containing monomers, alcoholic hydroxyl group-containing monomers, alkoxyl group-containing monomers, nitrile group-containing monomers, amide group-containing monomers, and amino group-containing monomers.The ethylenically unsaturated group-containing monomer may be a monomer having two or more ethylenically unsaturated groups in one molecule.Among these monomers, vinyl acetate, ethylenically unsaturated monocarboxylic acid esters, and ethylenically unsaturated monocarboxylic acids are preferably used.

[0040] Examples of vinyl carboxylate monomers include vinyl acetate, vinyl propionate, and derivatives thereof. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, and derivatives thereof. Examples of conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene, and derivatives thereof.

[0041] Examples of ethylenically unsaturated monocarboxylic acid esters include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, and derivatives thereof. Examples of ethylenically unsaturated polycarboxylic acid esters include dimethyl itaconate, diethyl maleate, monobutyl maleate, monoethyl fumarate, dibutyl fumarate, and derivatives thereof.

[0042] Examples of ethylenically unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, and derivatives thereof. Examples of ethylenically unsaturated dicarboxylic acids include itaconic acid, maleic acid, fumaric acid, and derivatives thereof. Examples of epoxy group-containing monomers include glycidyl methacrylate and derivatives thereof.

[0043] Examples of alcoholic hydroxyl group-containing monomers include 2-hydroxyethyl methacrylate and derivatives thereof. Examples of alkoxyl group-containing monomers include methoxyethyl acrylate and derivatives thereof. Examples of nitrile group-containing monomers include acrylonitrile and derivatives thereof. Examples of amide group-containing monomers include acrylamide and derivatives thereof. Examples of amino group-containing monomers include dimethylaminoethyl methacrylate and derivatives thereof. Examples of monomers having two or more ethylenically unsaturated groups in one molecule include divinylbenzene, allyl methacrylate, and derivatives thereof.

[0044] The ratio of the mass of the vinyl chloride monomer to the mass of the ethylenically unsaturated group-containing monomer is, for example, 50:50 to 100:0, and preferably 70:30 to 100:0. When the content of the vinyl chloride monomer is within the above range, for example, the generation of aggregates during the production of the dispersion 130 or during storage of the dispersion 130 can be suppressed. The aggregates are, for example, a mixture of vinyl chloride polymer and solid particles added to stabilize the dispersion. An example of the solid particles is silica.

[0045] (Water-Dispersible Oligomer) In this embodiment, the water-dispersible oligomer is a relatively low-molecular-weight resin that is dispersible in an aqueous solvent such as the dispersion medium 132. The water-dispersible oligomer is, for example, a polymer having a weight-average molecular weight of 5,000 to 50,000, expressed as a polystyrene-equivalent value measured by GPC (gel permeation chromatography). The water-dispersible oligomer may be a polymer having the weight-average molecular weight of 8,000 to 25,000. When the weight-average molecular weight of the water-dispersible oligomer is within the above numerical range, the generation of aggregates can be suppressed, for example, during the production of the dispersion 130 or during storage of the dispersion 130. The aggregates are, for example, a mixture of the water-dispersible oligomer and a vinyl chloride resin.

[0046] The water-dispersible oligomer includes, for example, at least one of a polymer of an ethylenically unsaturated group-containing monomer and a urethane-based polymer. The polymer of an ethylenically unsaturated group-containing monomer may be a homopolymer consisting essentially of a single type of monomer unit, or may be a copolymer containing multiple types of monomer units. Examples of the polymer of an ethylenically unsaturated group-containing monomer include an acrylic acid ester oligomer and a styrene-acrylic acid ester oligomer. Examples of the urethane-based polymer include a polycarbonate-based urethane oligomer and a polyester-based urethane oligomer.

[0047] The acrylic acid ester oligomer may be a homopolymer or copolymer of a (meth)acrylic acid ester monomer. The styrene-acrylic acid ester oligomer may be a copolymer of a styrene-based monomer and a (meth)acrylic acid ester-based monomer. Examples of (meth)acrylic acid ester-based monomers include methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate. The term (meth)acrylic is used as a general term for acrylic and methacrylic. Examples of acrylic acid ester oligomers or styrene-acrylic acid ester oligomers include JONCRYL JDX-6500 (manufactured by BASF Japan Ltd.), JONCRYL JDX-6102B (manufactured by BASF Japan Ltd.), JONCRYL HPD-96J (manufactured by BASF Japan Ltd.), and JONCRYL 52J (manufactured by BASF Japan Ltd.).

[0048] The polycarbonate-based urethane oligomer may be a homopolymer or copolymer of a polycarbonate-based diol monomer. Examples of polycarbonate-based urethane oligomers include ETERNACALL UW-1005E (manufactured by UBE Corporation), HYDRAN WLS-207 (manufactured by DIC Corporation), and HYDRAN WLS-230 (manufactured by DIC Corporation).

[0049] The water-dispersible oligomer may include at least one of an acrylic ester oligomer, a styrene-acrylic ester oligomer, and a polycarbonate-based urethane oligomer. The water-dispersible oligomer may include at least one of an acrylic ester oligomer, a styrene-acrylic ester oligomer, and a polycarbonate-based urethane oligomer. The water-dispersible oligomer may include an acrylic ester oligomer and / or a polycarbonate-based urethane oligomer.

[0050] The water-dispersible oligomer may have at least one of a carboxy group and a urethane group, which allows the water-dispersible oligomer to be configured to be dispersible in an aqueous solvent.

[0051] The water-dispersible oligomer may be substantially free of the above-described monomer units derived from vinyl chloride monomers. The proportion of the monomer units derived from vinyl chloride monomers contained in the water-dispersible oligomer may be less than 0.1 wt %.

[0052] (Outline of the stabilizer 136) In this embodiment, the stabilizer 136 suppresses aggregation or coalescence of the dispersoid 134 in the dispersion medium 132. This improves the dispersibility or dispersion stability of the dispersoid 134. In this embodiment, the stabilizer 136 includes, for example, solid particles having a median diameter of less than 1 μm as measured by dynamic light scattering. The above-mentioned solid particles may be used as the stabilizer 136.

[0053] The median diameter of the solid particles measured by dynamic light scattering may be less than 500 nm or less than 300 nm, and may be 6 nm or more and 100 nm or less, or 6 nm or more and 80 nm or less.

[0054] When the size of the solid particles is equal to or greater than the lower limit of the above-mentioned range, an increase in the viscosity of the dispersion 130 is suppressed, and a dispersion 130 having a viscosity suitable for use as a paint or water-based ink is obtained. When the size of the solid particles is equal to or less than the upper limit of the above-mentioned range, sedimentation of the dispersoids 134 can be appropriately suppressed.

[0055] As described above, in this embodiment, water or an aqueous solution of various substances is used as the dispersion medium 132. In this case, the stabilizer 136 may include solid particles having a median diameter of less than 1 μm as measured by dynamic light scattering and having hydrophilic functional groups on their surfaces. Examples of hydrophilic functional groups include hydroxyl groups and carboxyl groups. The above solid particles may be used as the stabilizer 136.

[0056] Examples of the solid particles include (i) inorganic fine particles having hydrophilic functional groups on their surfaces, and (ii) organic fine particles whose surfaces have been modified or altered to be hydrophilic. The solid particles may be colloidal silica, carbon black, and / or cellulose-based particles.

[0057] The solid particles may be colloidal silica having a median diameter of 6 nm to 100 nm as measured by dynamic light scattering. The colloidal silica may have a median diameter of 6 nm to 80 nm as measured by dynamic light scattering. The colloidal silica may be obtained, for example, by heat-aging a silica sol. The silica sol may be obtained, for example, by subjecting a product of a metathesis treatment of sodium silicate and an acid to an ion exchange treatment using an ion exchange resin.

[0058] The colloidal silica may be colloidal silica stabilized in a basic or neutral pH range. Examples of colloidal silica stabilized in a basic pH range include colloidal silica stabilized with ammonia, a sodium compound, a potassium compound, a calcium compound, and / or aluminum hydroxide. The colloidal silica may be colloidal silica stabilized with ammonia or colloidal silica stabilized with a sodium compound.

[0059] Examples of the colloidal silica include the "Snowtex series" manufactured by Nissan Chemical Industries, Ltd., the "Ludox series" manufactured by W.R. Grace Japan, Inc., and the "PL series" manufactured by Fuso Chemical Co., Ltd. One or more types of colloidal silica may be used as the solid particles.

[0060] According to this embodiment, the solid particles are adsorbed, coordinated, or attached to the interface between the dispersion medium 132 and the dispersoid 134, thereby suppressing aggregation or coalescence of the dispersoid 134 in the dispersion medium 132. This makes it possible to prepare a dispersion 130 or a coating material 140 that is substantially free of surfactants.

[0061] According to this embodiment, at least a portion of the solid particles added to the dispersion 130 as the stabilizer 136 are bound to the water-dispersible oligomer constituting the core-shell structure described above through intermolecular interactions. At least a portion of the solid particles may be adsorbed to the water-dispersible oligomer constituting the core-shell structure described above. At least a portion of the solid particles may be attached to the water-dispersible oligomer constituting the core-shell structure described above in a form other than a covalent bond. At least a portion of the solid particles may be attached to the water-dispersible oligomer constituting the core-shell structure described above in a form other than a chemical bond. The above solid particles are, for example, arranged on the outermost shell of the core-shell structure.

[0062] Examples of intermolecular interactions include electrostatic interactions, van der Waals interactions, interactions due to hydrogen bonds, interactions similar to hydrogen bonds, etc. Examples of interactions similar to hydrogen bonds include interactions between hydrogen atoms and π electrons, interactions between π electrons, interactions via coordinate bonds, and interactions that occur due to the transfer of electrons between molecules (sometimes referred to as charge transfer interactions).

[0063] (Other Additives) The dispersion 130 may contain various additives, for example, to the extent that the additives do not impair the alcohol resistance and / or flexibility of the composition derived from the dispersion 130. Examples of the additives include polymerization aids, plasticizers, inorganic fillers, organic fillers, thickeners, etc., which are added in the production process of the dispersion 130. Examples of the polymerization aids include emulsifiers, polymerization initiators, chain transfer agents, pH adjusters, antifoaming agents, surfactants, etc.

[0064] Examples of the emulsifier include alkyl sulfates, examples of the chain transfer agent include mercaptans, and examples of the pH adjuster include sodium carbonate.

[0065] Examples of surfactants include nonionic surfactants, anionic surfactants, etc. Specific examples of surfactants include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyethylene derivatives, glycerin fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamines, alkylalkanolamides, acetylene alcohols, acetylene glycols, and ethylene oxide adducts thereof.

[0066] As described above, the dispersion 130 may be substantially free of organic compound-based surfactants. The dispersion 130 may be substantially free of cationic surfactants and / or amphoteric surfactants, and may be substantially free of surfactants with a molecular weight of 1000 or less. This improves the water resistance and alcohol resistance of the composition derived from the dispersion 130.

[0067] Examples of polymerization initiators include persulfates, azo compounds, peroxides, tartaric acid, and redox initiators. Examples of persulfates include ammonium persulfate and potassium persulfate. Examples of azo compounds include 2,2'-diamidino-2,2'-azopropane dihydrochloride and azobisisobutyronitrile. Examples of peroxides include cumene hydroperoxide, benzoyl peroxide, and hydrogen peroxide. Examples of redox initiators include potassium persulfate and sodium hydrogen sulfite.

[0068] (Composition Ratio of Each Component in Dispersion 130) In the present embodiment, dispersion 130 contains the vinyl chloride resin, the water-dispersible oligomer, and the solid particles. For example, dispersion 130 contains 10 parts by mass or more and 40 parts by mass or less of the vinyl chloride resin, 5 parts by mass or more and 30 parts by mass or less of the water-dispersible oligomer, and 50 parts by mass or more and 65 parts by mass or less of the solid particles, relative to a total of 100 parts by mass of the vinyl chloride resin, the water-dispersible oligomer, and the solid particles. This provides dispersion 130 that is particularly suitable as a raw material for inks, paints, binders for dispersing inorganic substances, recording layers of recording media, fiber treatment agents, various coatings, and the like.

[0069] For example, the synthetic resin emulsions described in Patent Documents 1 to 5 do not contain solid particles that function as stabilizer 136. Therefore, the aqueous inks prepared using the synthetic resin emulsions described in Patent Documents 1 to 5 have room for improvement in terms of print bleeding, blocking resistance, and alcohol resistance. Similarly, the recording media having a recording layer prepared using the synthetic resin emulsions described in Patent Documents 1 to 5 have room for improvement in terms of print bleeding, blocking resistance, flexibility, and alcohol resistance of the recording layer.

[0070] For example, the synthetic resin emulsion described in Patent Document 6 contains a surfactant in addition to silica microparticles, resulting in poor water resistance. The synthetic resin emulsion described in Patent Document 7 contains a reactive anionic emulsifier, resulting in poor water resistance. The synthetic resin emulsion described in Patent Document 8 has a low vinyl chloride polymer content, resulting in poor alcohol resistance. The synthetic resin emulsion described in Patent Document 9 has a low solids content, resulting in poor hydrophilicity of the coating film of the synthetic resin emulsion.

[0071] In contrast, when the dispersion 130 having the above composition is used as a raw material for inks, paints, binders for dispersing inorganic substances, recording layers of recording media, fiber treatment agents, various coatings, etc., products with excellent coatability, water resistance, alcohol resistance, abrasion resistance, and / or sliding properties can be obtained. In addition, the hydrophilicity or wettability of a coating film derived from the dispersion 130 can be improved.

[0072] According to one embodiment, for example, an aqueous ink having excellent water resistance, moisture resistance, color visibility, gloss, and / or alcohol resistance can be obtained. In particular, an aqueous ink having excellent alcohol resistance can be obtained. According to another embodiment, for example, a recording medium having a recording layer having excellent color development, gloss, water resistance, moisture resistance, hydrophilicity or wettability, and / or alcohol resistance can be obtained. In particular, a recording medium having a recording layer having excellent alcohol resistance and / or hydrophilicity or wettability can be obtained.

[0073] In this embodiment, the mass ratio of the vinyl chloride resin to the total mass of the vinyl chloride resin, the water-dispersible oligomer, and the solid particles may be 10% by mass or more and 40% by mass or less. The above ratio may be 10% by mass or more and 39% by mass or less, and preferably 15% by mass or more and 35% by mass or less. When the above ratio is within the above numerical range, for example, the polymerization stability of the vinyl chloride resin in the production process of the dispersion 130 is improved.

[0074] In this embodiment, the ratio of the mass of the water-dispersible oligomer to the total mass of the vinyl chloride resin, the water-dispersible oligomer, and the solid particles may be 1% by mass or more and 40% by mass or less. The ratio may be 5% by mass or more and 35% by mass or less, and preferably 8% by mass or more and 15% by mass or less. When the ratio is equal to or greater than the lower limit of the above-mentioned range, for example, the generation of aggregates in the dispersion 130 can be suppressed. When the ratio is equal to or less than the upper limit of the above-mentioned range, for example, a dispersion 130 with excellent stability over time can be obtained. Furthermore, the polymerization stability of the vinyl chloride resin in the production process of the dispersion 130 can be improved.

[0075] In this embodiment, the ratio of the mass of the solid particles to the total mass of the vinyl chloride resin, the water-dispersible oligomer, and the solid particles may be 50% by mass or more and 65% by mass or less. The ratio may be 51% by mass or more and 64% by mass or less, and preferably 55% by mass or more and 60% by mass or less. When the ratio is equal to or greater than the lower limit of the above-mentioned range, for example, the composition derived from the dispersion 130 exhibits excellent alcohol resistance. When the ratio is less than the upper limit of the above-mentioned range, the dispersion 130 has excellent film-forming properties. Furthermore, the polymerization stability of the vinyl chloride resin during the production process of the dispersion 130 is improved.

[0076] The ratio of the mass of the water-dispersible oligomer to the mass of the vinyl chloride resin may be 10% by mass or more and 100% by mass or less, 20% by mass or more and 80% by mass or less, and preferably 40% by mass or more and 70% by mass or less.

[0077] The ratio of the mass of the solid particles to the mass of the vinyl chloride resin may be 100% by mass or more and 500% by mass or less, 120% by mass or more and 300% by mass or less, and preferably 150% by mass or more and 200% by mass or less.

[0078] The ratio of the mass of the solid particles to the mass of the water-dispersible oligomer may be 200% by mass or more and 600% by mass or less, or 250% by mass or more and 550% by mass or less, and preferably 300% by mass or more and 500% by mass or less.

[0079] In this embodiment, the ratio of the mass of the solid content contained in the dispersion 130 to the mass of the dispersion 130 may be 10% by mass or more and 50% by mass or less. The above ratio may be 20% by mass or more and 40% by mass or less, and preferably 25% by mass or more and 30% by mass or less. The mass of the solid content may be the total mass of the vinyl chloride resin, the water-dispersible oligomer, and the solid particles. When the above ratio is equal to or greater than the lower limit of the above numerical range, a dispersion 130 that exhibits one or more of the above-described effects can be obtained. When the above ratio is equal to or less than the upper limit of the above numerical range, for example, gelation of the dispersion 130 can be suppressed.

[0080] (Physical Properties of Dispersion 130) The viscosity of the dispersion 130 may be 1 to 1800 mPa·s in a temperature range of 22.5°C or higher and 23.5°C or lower. The viscosity of the dispersion 130 may be 1 to 1000 mPa·s, and is preferably 1 to 500 mPa·s, in the above temperature range. The viscosity of the dispersion 130 is measured, for example, using a B-type viscometer (TVB-10M, No. 1 rotor, 6 rpm, manufactured by Toki Sangyo Co., Ltd.). The viscosity of the dispersion 130 is measured, for example, in accordance with JIS K-7117-1:1999.

[0081] The median diameter of the dispersoids 134 contained in the dispersion 130, as measured by dynamic light scattering, may be 10 nm or more and 600 nm or less. The median diameter, as measured by dynamic light scattering, may be 20 nm or more and 500 nm or less, preferably 20 nm or more and 120 nm or less, and more preferably 20 nm or more and 100 nm or less.

[0082] (Composition of Paint 140) As described above, the paint 140 includes the dispersion 130. The ratio of the mass of the solid content contained in the dispersion 130 to the mass of the paint 140 may be 2 mass% or more and 30 mass% or less. The above ratio is preferably 5 mass% or more and 20 mass% or less. The mass of the solid content may be the total mass of the vinyl chloride resin, the water-dispersible oligomer, and the solid particles.

[0083] The paint 140 may contain (a) the dispersion liquid 130 and (b) at least one of a colorant and a solvent. Examples of the colorant include pigments and dyes. Examples of the solvent include water, aqueous solutions of various substances, and water-soluble organic solvents. The paint 140 may further contain additives such as pigment dispersants, leveling agents, antifoaming agents, colorants, antioxidants, UV absorbers, viscosity modifiers, and release agents. These additives are used, for example, in amounts typically used in aqueous inks.

[0084] Examples of water-soluble organic solvents include ethylene glycol monoether, diethylene glycol monoether, propylene glycol monoether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol, diethylene glycol, propylene glycol, glycerin, methanol, ethanol, isopropyl alcohol, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, acetone, ethyl acetate, and diacetone alcohol. The mass ratio of the water-soluble organic solvent to the mass of the paint 140 may be 0 to 60% by mass, and preferably 0 to 50% by mass. When water is used as the solvent, the mass ratio of water to the mass of the paint 140 may be 5 to 95% by mass, and preferably 10 to 90% by mass.

[0085] Examples of pigments include amorphous synthetic silica, aluminum silicate, magnesium silicate, precipitated calcium carbonate, heavy calcium carbonate, calcium silicate, aluminum hydroxide, zeolite, calcined clay, kaolin clay, talc, white carbon, etc. The ratio of the mass of the pigment to the mass of the paint 140 may be 10 to 90% by mass, and preferably 20 to 80% by mass.

[0086] In this embodiment, the paint 140 may be substantially free of organic compound-based surfactants. The paint 140 may be substantially free of cationic surfactants and / or amphoteric surfactants. The paint 140 may be substantially free of surfactants with a molecular weight of 1000 or less. For example, the content of surfactants in the paint 140 may be 100 ppm or less or 100 g / m ３ (sometimes referred to as ppm) or less, it can be determined that the paint 140 is substantially free of the surfactant.

[0087] As described above, the coating material 140 dries to form the recording layer 120. This results in the recording layer 120 containing the vinyl chloride resin, the water-dispersible oligomer, and the solid particles. The recording layer 120 contains, for example, 10 to 40 parts by mass of the vinyl chloride resin, 5 to 30 parts by mass of the water-dispersible oligomer, and 50 to 65 parts by mass of the solid particles (i.e., particles with a median diameter of less than 1 μm as measured by dynamic light scattering), relative to a total of 100 parts by mass of the vinyl chloride resin, the water-dispersible oligomer, and the solid particles.

[0088] The dispersion liquid 130 may be an example of an aqueous dispersion. The dispersion medium 132 may be an example of an aqueous solvent. The dispersoid 134 may be an example of a core-shell structure. The stabilizer 136 may be an example of solid particles. The paint 140 may be an example of a water-based ink.

[0089] (Another Example of an Embodiment) In the present embodiment, the details of the recording medium 100 have been described using an example in which the recording medium 100 includes the substrate 110 and the recording layer 120. However, the recording medium 100 is not limited to this embodiment. In other embodiments, the recording medium 100 may include other layers. The other layers may be disposed, for example, between the substrate 110 and the recording layer 120. When the recording layer 120 is disposed on the first surface side of the substrate 110, the other layers may be disposed on the second surface of the substrate 110. The second surface of the substrate 110 may be a surface different from the first surface of the substrate 110. When the substrate 110 is disposed on the first surface side of the recording layer 120, the other layers may be disposed on the second surface of the recording layer 120. The second surface of the recording layer 120 may be a surface different from the first surface of the recording layer 120.

[0090] In this embodiment, the dispersion 130 and the paint 140 have been described in detail using the example in which the paint 140 is used to produce the recording layer 120. However, the dispersion 130 and / or the paint 140 are not limited to this embodiment. In other embodiments, the paint 140 may be a vinyl chloride-based water-based ink, and the dispersion 130 may be used as a binder for the vinyl chloride-based water-based ink.

[0091] (Outline of Core-Shell Structure) The above-mentioned core-shell structure will be described in detail using Fig. 2. Fig. 2 shows a schematic diagram of an example of a dispersoid 134 having a core-shell structure. Fig. 2 also shows a schematic diagram of an example of a state in which the dispersoid 134 is dispersed in the dispersion medium 132.

[0092] 2 , in this embodiment, the dispersoid 134 includes a core 210 and one or more water-dispersible oligomers 220 disposed on the outside of the core 210. The core 210 includes one or more vinyl chloride resins 212. Each of the one or more water-dispersible oligomers 220 is disposed so as to cover at least a portion of the core 210. The one or more water-dispersible oligomers 220 may be referred to as a shell.

[0093] According to this embodiment, the solid particles functioning as the stabilizer 136 are bound by intermolecular interactions to one or more water-dispersible oligomers 220 that form the shell of the dispersoid 134. The solid particles are adsorbed, coordinated, or attached to the interface between the dispersion medium 132 and the dispersoid 134, thereby stabilizing the dispersion 130.

[0094] The vinyl chloride resin 212 may be an example of a vinyl chloride polymer, and the water-dispersible oligomer 220 may be an example of a water-dispersible polymer.

[0095] 3 schematically shows an example of a method for producing the dispersion 130. As described above, the dispersion 130 can be obtained, for example, by mixing (i) one or more monomers that serve as structural units of the vinyl chloride resin described above, (ii) the water-dispersible oligomer described above, (iii) solid particles that function as the stabilizer 136 described above, and (iv) an aqueous solvent, and polymerizing the monomers in the resulting reaction liquid.

[0096] In one embodiment, when the vinyl chloride resin is a homopolymer, the reaction liquid is obtained by mixing a vinyl chloride monomer, a water-dispersible oligomer, solid particles, and an aqueous solvent. The reaction liquid is adjusted to contain, for example, 10 to 40 parts by mass of the vinyl chloride monomer, 5 to 30 parts by mass of the water-dispersible oligomer, and 50 to 65 parts by mass of the solid particles, relative to a total of 100 parts by mass of the vinyl chloride monomer, the water-dispersible oligomer, and the solid particles.

[0097] In this embodiment, the ratio of the mass of the vinyl chloride monomer to the total mass of the vinyl chloride monomer, the water-dispersible oligomer, and the solid particles may be 10% by mass or more and 40% by mass or less. The ratio may be 10% by mass or more and 39% by mass or less, and preferably 15% by mass or more and 35% by mass or less. When the ratio is within the above range, for example, the polymerization stability of the vinyl chloride resin in the production process of the dispersion 130 is improved.

[0098] In another embodiment, when the vinyl chloride resin is a copolymer, the reaction liquid is obtained by, for example, mixing a vinyl chloride monomer, an ethylenically unsaturated group-containing monomer copolymerizable with the vinyl chloride monomer, a water-dispersible oligomer, solid particles, and an aqueous solvent. The reaction liquid is adjusted to contain, for example, 10 to 40 parts by mass of the vinyl chloride monomer, 5 to 10 parts by mass of the ethylenically unsaturated group-containing monomer copolymerizable with the vinyl chloride monomer, 5 to 30 parts by mass of the water-dispersible oligomer, and 50 to 65 parts by mass of the solid particles, per 100 parts by mass of the vinyl chloride monomer, the water-dispersible oligomer, and the solid particles combined.

[0099] In this embodiment, the ratio of the total mass of the vinyl chloride monomer and the ethylenically unsaturated group-containing monomer to the total mass of the vinyl chloride monomer, the ethylenically unsaturated group-containing monomer, the water-dispersible oligomer, and the solid particles may be 15% by mass or more and 50% by mass or less. The ratio may be 17% by mass or more and 45% by mass or less, and preferably 20% by mass or more and 40% by mass or less. When the ratio is within the above numerical range, for example, the polymerization stability of the vinyl chloride resin in the production process of the dispersion 130 is improved.

[0100] 3, according to this embodiment, first, in step 322 (which may be abbreviated as S), the dispersion medium 132 described above is prepared. Also, a core-forming monomer and a shell-forming polymer to be used in producing the dispersoid 134 are prepared. Furthermore, the solid particles described above are prepared as the stabilizer 136.

[0101] The core-forming monomer may be the vinyl chloride monomer described above, or a mixture of the vinyl chloride monomer and an ethylenically unsaturated group-containing monomer described above. The shell-forming polymer may be the water-dispersible oligomer described above.

[0102] Next, in S324, the dispersion medium 132, the core-forming monomer, the shell-forming polymer, and the stabilizer 136 are mixed to prepare a reaction liquid. According to one embodiment, 10 to 40 parts by mass of the core-forming monomer, 5 to 30 parts by mass of the shell-forming polymer, and 50 to 65 parts by mass of the solid particles are added to the dispersion medium 132 relative to a total of 100 parts by mass of the core-forming monomer, the shell-forming polymer, and the solid particles. These components are thoroughly mixed to prepare the reaction liquid. According to another embodiment, 10 to 40 parts by mass of the vinyl chloride monomer, 5 to 30 parts by mass of the water-dispersible oligomer, and 50 to 65 parts by mass of the solid particles are added to the dispersion medium 132 relative to a total of 100 parts by mass of the vinyl chloride monomer, the water-dispersible oligomer, and the solid particles. These components are thoroughly mixed to prepare the reaction liquid.

[0103] The amount of dispersion medium 132 added is adjusted, for example, so that the solids concentration in the reaction solution is 10% by mass or more and 50% by mass or less. The amount of dispersion medium 132 added may also be adjusted so that the solids concentration in the reaction solution is 20% by mass or more and 40% by mass or less. As described above, the reaction solution may be substantially free of organic compound-based surfactants. Furthermore, the reaction solution may be substantially free of cationic surfactants and / or amphoteric surfactants. The reaction solution may be substantially free of surfactants with a molecular weight of 1,000 or less.

[0104] Next, in S326, a process for initiating the polymerization reaction of the core-forming monomer is carried out. For example, the reaction solution is heated, and after the temperature of the reaction solution reaches a predetermined temperature, the above-described polymerization initiator is added to the reaction solution. The predetermined temperature may be 40°C or higher and 80°C or lower, and preferably 50°C or higher and 70°C or lower. The ratio of the amount of polymerization initiator added to the mass of the core-forming monomer may be 0.1% by mass or higher and 2.0% by mass or lower, and preferably 0.2% by mass or higher and 1.0% by mass or lower.

[0105] This allows the polymerization reaction of the core-forming monomer to proceed in the reaction solution. According to this embodiment, the polymerization reaction of the core-forming monomer proceeds in the presence of the water-dispersible oligomer and the solid particles. As a result, the dispersoids 134 having the above-described core-shell structure are produced.

[0106] After it is confirmed that the polymerization of the core-forming monomer has progressed sufficiently, a treatment is carried out to terminate the polymerization reaction of the core-forming monomer, thereby producing a dispersion liquid 130.

[0107] The polymerization conditions and / or polymerization process of the core-forming monomer may be similar to those of known vinyl chloride resins. The core-forming monomer and various polymerization aids may be added all at once at the beginning of the polymerization, in portions, or continuously. The polymerization time may be 10 hours or more and 15 hours or less. The polymerization reaction may be carried out under an inert gas atmosphere such as nitrogen gas. After the polymerization is completed, any plasticizer, inorganic filler, organic filler, thickener, etc. may be added.

[0108] In one embodiment, the polymerization reaction of the core-forming monomer proceeds in the presence of an organic compound-based surfactant. In another embodiment, the polymerization reaction of the core-forming monomer proceeds in a reaction solution that is substantially free of an organic compound-based surfactant. In this case, the polymerization conditions and / or polymerization process can be determined by a procedure similar to that of known soap-free polymerization or Pickering polymerization. For example, the step of polymerizing the core-forming monomer may include the following steps: (i) adjusting the concentration of the surfactant having a molecular weight of 1,000 or less in the reaction solution to 100 g / m３ The method includes a step of polymerizing a core-forming monomer under the following conditions: (i) the ratio of the mass of a surfactant having a molecular weight of 1,000 or less to the mass of the core-forming monomer is less than 0.001 mass %;

[0109] The present invention will be specifically described below with reference to examples. Note that the present invention is not limited to the following production examples, synthesis examples, or examples. Furthermore, unless otherwise specified, "parts" represents "parts by mass" and "%" represents "% by mass."

[0110] Example 1 After the interior of a polymerization vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet was purged with nitrogen, 910 parts of deionized water, 215 parts of vinyl chloride, 340 parts by mass of JONCRYL JDX-6500 (manufactured by BASF, acrylic oligomer as an active ingredient: 30%), and 100 parts by mass of Snowtex S (manufactured by Nissan Chemical Industries, Ltd., solid content SiO as an active ingredient) were charged into the polymerization vessel. ２ The composition of the raw materials for the aqueous dispersion is shown in Table 1.

[0111] JONCRYL JDX-6500 is an acrylic oligomer with a weight-average molecular weight of 10,000. Snowtex S is a sodium-stable colloidal silica with a pH of 9.5 to 10.0. The median diameter of the colloidal silica contained in Snowtex S is 9 nm as measured by dynamic light scattering.

[0112] While stirring the raw materials (sometimes referred to as the reaction liquid) charged inside the polymerization vessel, the reaction liquid was heated until its temperature reached 60°C. After confirming that the temperature of the reaction liquid had reached 60°C, a solution obtained by dissolving 4 parts of ammonium persulfate in 50 parts of deionized water was added to the reaction liquid as a polymerization initiator. When the internal pressure of the polymerization vessel reached 0.1 MPa, residual monomers were removed in a vacuum to 1000 ppm, and then the reaction liquid was cooled to 40°C or below. Thereafter, 10 parts of 25% aqueous ammonia were added to the reaction liquid. This produced an aqueous dispersion of vinyl chloride resin.

[0113] Considering the properties of the vinyl chloride resin, acrylic oligomer, and colloidal silica, it was presumed that a core-shell structure was formed in the aqueous dispersion, in which the acrylic oligomer was arranged so as to cover the vinyl chloride resin, and that a portion of the colloidal silica was bonded to, adsorbed onto, or adhered to the surface of the core-shell structure.

[0114] The physical properties of the resulting aqueous dispersion were then measured. Specifically, the solids concentration, pH, and viscosity of the aqueous dispersion were measured according to the following procedures. Furthermore, the median diameter of the particles dispersed in the aqueous dispersion was measured by dynamic light scattering. The measurement results for the physical properties of the aqueous dispersion and the particles are shown in Table 1.

[0115] (Solid content concentration) First, an aluminum foil dish with a diameter of 70 mm and a depth of 12 mm was prepared. The mass A (g) of the aluminum foil dish was measured. Next, approximately 1 g of the aqueous dispersion obtained in Example 1 was dispensed into the aluminum foil dish. The mass W (g) of the dish containing the aqueous dispersion was measured. Next, the dish containing the aqueous dispersion was left inside a dryer for 1 hour to evaporate the water contained in the aqueous dispersion. The temperature of the dryer was maintained at 105 to 110°C. Next, the aluminum foil dish was removed from the dryer and allowed to cool inside a desiccator. The mass D (g) of the aluminum foil dish after cooling was measured.

[0116] The solid content concentration R (%) was calculated using the following mathematical formula (1): The solid content concentration in the aqueous dispersion was 25 mass %. (Mathematical formula 1) R = (D - A) / (W - A) x 100

[0117] (pH) The pH of the aqueous dispersion was measured according to JIS Z8802 (pH measurement method). A glass electrode hydrogen ion concentration indicator (Model D-55, manufactured by Horiba, Ltd.) was used to measure the pH. The pH of the aqueous dispersion was 9.3.

[0118] (Viscosity) The viscosity of the aqueous dispersion was measured using a Brookfield viscometer (TVB-10M manufactured by Toki Sangyo Co., Ltd., No. 1 rotor, 6 rpm). During the measurement period, the temperature of the aqueous dispersion was maintained at 22.5°C or higher and 23.5°C or lower. The viscosity of the aqueous dispersion was 2 mPa s.

[0119] (Median diameter by dynamic light scattering) The median diameter of particles contained in the aqueous dispersion obtained in Example 1 was measured by dynamic light scattering using a light-scattering particle size analyzer (ELSZ-2000ZS, manufactured by Otsuka Electronics). Specifically, a sample of the aqueous dispersion was first collected in a plastic container and diluted 1000 times with pure water at 25°C. The diluted sample was then placed in the light-scattering particle size analyzer. Next, it was confirmed that the concentration of the sample was within the appropriate concentration range, and particle size measurement was started under the conditions of a measurement liquid temperature of 25°C, an accumulation number of 25, and a measurement number of 1. The median diameter of particles dispersed in the aqueous dispersion was 25.7 nm.

[0120] (Evaluation) Next, the properties of the aqueous dispersion and the properties of the coating film obtained by applying and drying the aqueous dispersion were evaluated according to the following procedures. Specifically, the stability of the aqueous dispersion was evaluated as a property of the aqueous dispersion. Furthermore, the coatability, water resistance, alcohol resistance, and wettability of the coating film were evaluated as properties of the coating film. The evaluation results of the aqueous dispersion and the coating film are shown in Table 3.

[0121] (Stability of aqueous dispersion) After preparing the aqueous dispersion, the aqueous dispersion was left to stand for one month. Thereafter, the aqueous dispersion was filtered using a 300 mesh filter cloth, and the presence or absence of aggregates on the filter cloth was visually confirmed. In Table 4, ○ indicates that no aggregates were observed. × indicates that aggregates were observed or that gelation of the aqueous dispersion was observed.

[0122] (Coatability of coating film) The aqueous dispersion obtained in Example 1 was coated on the surface of a PET film (Torel Lumirror L-75) using a bar coater No. 10. The PET film coated with the aqueous dispersion was dried at 105°C for 300 seconds. This gave a coating film of the aqueous dispersion of Example 1.

[0123] The appearance of the coating film produced by the above procedure was observed visually and with a microscope (manufactured by Keyence Corporation) to confirm the state of the coating film and the degree of circular depressions called repelling (cissing or cratering). Based on the above observation results, the coatability of the coating film was evaluated as follows. In Table 4, ○ indicates that the wettability to the substrate was good and a continuous film was formed. △ indicates that the wettability to the substrate was poor or a continuous film was not formed. × indicates that the wettability to the substrate was poor and a continuous film was not formed.

[0124] (Water resistance of coating film: abrasion test) A cotton swab moistened with pure water was rubbed against the coating film prepared by the above procedure, and the cotton swab was rubbed back and forth 10 times. The condition of the coating film was visually observed, and the percentage (%) of the area where no abnormality in the coating film was observed relative to the area where the cotton swab was rubbed was calculated. If whitening or peeling of the coating film was observed, the condition of the coating film was determined to be abnormal.

[0125] (Alcohol resistance of coating film: droplet test) A droplet test was carried out with varying ethanol concentrations. Specifically, a droplet test was carried out when the ethanol concentration was 80% by mass and a droplet test was carried out when the ethanol concentration was approximately 100% (for example, anhydrous ethanol with an ethanol concentration of 99.5% by mass or more).

[0126] The droplet test was carried out according to the following procedure. First, a drop of ethanol was placed on the coating film prepared by the above procedure and left to stand for 1 minute. After wiping off the ethanol on the coating film, the condition of the coating film was observed. Based on the observation results, the water resistance of the coating film was evaluated as follows. In Table 4, ○ indicates that no whitening or dissolution of the coating film was observed and the coating film remained transparent. △ indicates that slight whitening of the coating film was observed and the coating film had turned translucent. × indicates that whitening or dissolution of the coating film was observed.

[0127] (Alcohol Resistance of Coating Film: Scratch Test) Scratch tests were conducted using different ethanol concentrations. Specifically, a scratch test was conducted when the ethanol concentration was 80% by mass, and a scratch test was conducted when the ethanol concentration was approximately 100% (for example, absolute ethanol with an ethanol concentration of 99.5% by mass or more).

[0128] The scratch test was carried out according to the following procedure. First, a cotton swab moistened with ethanol was rubbed against the coating film prepared by the above procedure, and the cotton swab was rubbed back and forth 10 times. The condition of the coating film was visually observed, and the percentage (%) of the area where no abnormality was observed in the coating film relative to the area where the cotton swab was rubbed was calculated. If whitening or peeling of the coating film was observed, the condition of the coating film was determined to be abnormal.

[0129] (Wettability of Coating Film) A 2.0 μL droplet of ion-exchanged water was contacted with the coating film prepared by the above procedure, and the contact angle was measured using an automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., model CA-V series) at 1 second, 30 seconds, 60 seconds, and 90 seconds after the droplet and fiber came into contact. The contact angle measurements were carried out in an atmosphere at a temperature of 23°C and a humidity of 45%. If the contact angle was 40 to 74°, it was determined that a coating film with excellent wettability had been obtained. Furthermore, if the contact angle was 40 to 70°, it was determined that a coating film with very excellent wettability had been obtained.

[0130] (Examples 2 to 5) Aqueous dispersions were prepared using the same procedure as in Example 1, except that the composition ratios of the raw materials were changed. The physical properties of the aqueous dispersions obtained in each example were measured using the same procedure as in Example 1. The composition of the raw materials for the aqueous dispersions in each example is shown in Table 1. The measurement results for the physical properties of the aqueous dispersions in each example are shown in Table 1.

[0131] Hiros X RL-1064 (manufactured by Seiko PMC Corporation, acrylic oligomer as an active ingredient: 29.2%) is an acrylic oligomer having a weight average molecular weight of 35,000. Snowtex 50-T (manufactured by Nissan Chemical Industries, Ltd., solid content SiO as an active ingredient) ２: 48%) is a Na-stable colloidal silica with a pH of 9.5 to 10.0. The average particle size of the colloidal silica contained in Snowtex 50-T is 22 nm. Snowtex YL (manufactured by Nissan Chemical Industries, Ltd., solid content SiO as an active ingredient) ２ : 40%) is a sodium-stable colloidal silica with a pH of 9.5 to 10.0. The average particle size of the colloidal silica contained in Snowtex YL is 60 nm.

[0132] The properties of the aqueous dispersions and coating films obtained in each example were evaluated using the same procedures as in Example 1. Table 3 shows the evaluation results of the aqueous dispersions and coating films obtained in each example.

[0133] (Comparative Examples 1 to 6) Aqueous dispersions were prepared in the same manner as in Example 1, except that the composition ratios of the raw materials were changed. The physical properties of the aqueous dispersions obtained in each Comparative Example were measured in the same manner as in Example 1. The composition of the raw materials for the aqueous dispersions in each Comparative Example is shown in Table 2. The measurement results for the physical properties of the aqueous dispersions in each Comparative Example are shown in Table 2.

[0134] Vinyblan 278 (manufactured by Nissin Chemical Industry Co., Ltd.) is a vinyl chloride emulsion with a solid content of 43%. The vinyl chloride resin contained in Vinyblan 278 does not have a core-shell structure and contains a surfactant with a molecular weight of 1,000 or less as a stabilizer.

[0135] The properties of the aqueous dispersions and coating films obtained in each Comparative Example were evaluated using the same procedures as in Example 1. Table 4 shows the evaluation results of the aqueous dispersions and coating films obtained in each Comparative Example.

[0136] It was relatively difficult to form a film during coating with the aqueous dispersion of Comparative Example 1. Therefore, the contact angle of the coating film formed with the aqueous dispersion of Comparative Example 1 could not be evaluated.

[0137] It was relatively difficult to form a film during coating with the aqueous dispersion of Comparative Example 3. Therefore, it was not possible to evaluate the water resistance, alcohol resistance, and contact angle of the coating film formed with the aqueous dispersion of Comparative Example 3.

[0138]

[0139]

[0140]

[0141]

[0142] Tables 3 and 4 show that compositions (for example, coating films) with excellent alcohol resistance can be obtained using the aqueous dispersions of Examples 1 to 6. In particular, the aqueous dispersions of Examples 1 to 6 can provide compositions with excellent water resistance, alcohol resistance, and wettability.

[0143] For example, when the aqueous dispersion according to this embodiment is used as an aqueous ink or a raw material for an aqueous ink, an aqueous ink having excellent water resistance, moisture resistance, high gloss, and alcohol resistance can be obtained. Furthermore, when the aqueous dispersion according to this embodiment is used as a raw material for a recording medium, a recording medium having excellent color development, water resistance, moisture resistance, color visibility, and high gloss can be obtained. This demonstrates that the aqueous dispersion according to this embodiment has properties particularly suitable for applications such as binders for inks, paints, and inorganic substance dispersions, receiving layers for recording media, and fiber treatment agents.

[0144] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, matters described for a particular embodiment can be applied to other embodiments to the extent that they are not technically inconsistent. Furthermore, each component may have the same features as other components with the same name but different reference numerals. It is apparent from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0145] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order.

[0146] REFERENCE SIGNS LIST 100 Recording medium 110 Substrate 120 Recording layer 130 Dispersion liquid 132 Dispersion medium 134 Dispersoid 136 Stabilizer 140 Coating material 150 Coating layer 210 Core 212 Vinyl chloride resin 220 Water-dispersible oligomer

Claims

1. a vinyl chloride polymer; a water-dispersible polymer having a weight average molecular weight of 5,000 or more and 50,000 or less; solid particles having a median diameter of less than 1 μm as measured by a dynamic light scattering method and having hydrophilic functional groups on their surfaces; Including, the vinyl chloride polymer is contained in an amount of 10 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the total of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles, the water-dispersible polymer is contained in an amount of 5 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the total of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles, the solid particles are contained in an amount of 50 parts by mass or more and 65 parts by mass or less relative to 100 parts by mass of the total of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles, Aqueous dispersion.

2. The water-dispersible polymer has at least one of a carboxy group and a urethane group. The aqueous dispersion of claim 1.

3. The water-dispersible polymer includes at least one of a polymer of an ethylenically unsaturated group-containing monomer and a urethane-based polymer. The aqueous dispersion of claim 1.

4. The water-dispersible polymer contains at least one of an acrylic ester oligomer, a styrene-acrylic ester oligomer, a polycarbonate-based urethane oligomer, and a polyester-based urethane oligomer. The aqueous dispersion of claim 1.

5. the vinyl chloride polymer and the water-dispersible polymer form a core-shell structure in which the water-dispersible polymer covers the vinyl chloride polymer; The aqueous dispersion of claim 1.

6. the solid particles are bound to the water-dispersible polymer constituting the core-shell structure by intermolecular interactions; The aqueous dispersion of claim 5.

7. (i) The content of the surfactant having a molecular weight of 1,000 or less in the aqueous dispersion is 100 g / m ３ is equal to or less than (ii) the ratio of the mass of the surfactant having a molecular weight of 1,000 or less to the mass of the vinyl chloride polymer is less than 0.001 mass%; The aqueous dispersion of claim 1.

8. a ratio of the mass of the solid content of the aqueous dispersion to the mass of the aqueous dispersion is 10 mass% or more and 50 mass% or less; The aqueous dispersion of claim 1.

9. the solid particles contain colloidal silica having a median diameter of 6 nm or more and 100 nm or less as measured by a dynamic light scattering method; The aqueous dispersion of claim 1.

10. An aqueous dispersion obtained by polymerizing vinyl chloride monomer in a reaction liquid obtained by mixing a vinyl chloride monomer, a water-dispersible polymer having a weight-average molecular weight of 5,000 or more and 50,000 or less, solid particles having a median diameter of less than 1 μm as measured by a dynamic light scattering method and having hydrophilic functional groups on the surface thereof, and an aqueous solvent, the reaction liquid contains 10 parts by mass or more and 40 parts by mass or less of the vinyl chloride monomer relative to 100 parts by mass in total of the vinyl chloride monomer, the water-dispersible polymer, and the solid particles, the reaction liquid contains the water-dispersed polymer in an amount of 5 parts by mass or more and 30 parts by mass or less relative to a total of 100 parts by mass of the vinyl chloride monomer, the water-dispersed polymer, and the solid particles, the reaction liquid contains 50 parts by mass or more and 65 parts by mass or less of the solid particles relative to a total of 100 parts by mass of the vinyl chloride monomer, the water-dispersible polymer, and the solid particles, Aqueous dispersion.

11. (i) The concentration of the surfactant having a molecular weight of 1,000 or less in the aqueous dispersion is 100 g / m ３ is equal to or less than (ii) the ratio of the mass of the surfactant having a molecular weight of 1000 or less to the mass of the vinyl chloride monomer is less than 0.001 mass%; The aqueous dispersion of claim 10.

12. The aqueous dispersion according to any one of claims 1 to 11, Water-based ink.

13. A recording layer comprising a composition derived from the aqueous dispersion according to any one of claims 1 to 11. Recording medium.

14. A substrate; a recording layer disposed on at least one surface of the substrate; Equipped with The recording layer is a vinyl chloride polymer; a water-dispersible polymer having a weight average molecular weight of 5,000 or more and 50,000 or less; solid particles having a median diameter of less than 1 μm as measured by a dynamic light scattering method and having hydrophilic functional groups on their surfaces; Including, the vinyl chloride polymer is contained in an amount of 10 parts by mass or more and 40 parts by mass or less relative to 100 parts by mass of the total of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles, the water-dispersible polymer is contained in an amount of 5 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the total of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles, the solid particles are contained in an amount of 50 parts by mass or more and 65 parts by mass or less relative to 100 parts by mass of the total of the vinyl chloride polymer, the water-dispersible polymer, and the solid particles, Recording medium.

15. preparing a reaction liquid by mixing vinyl chloride monomer, a water-dispersible polymer having a weight average molecular weight of 5,000 or more and 50,000 or less, solid particles having a median diameter of less than 1 μm as measured by a dynamic light scattering method and having hydrophilic functional groups on the surface thereof, and an aqueous solvent; polymerizing the vinyl chloride monomer in the presence of the water-dispersible polymer and the solid particles; and the reaction liquid contains 10 parts by mass or more and 40 parts by mass or less of the vinyl chloride monomer relative to 100 parts by mass in total of the vinyl chloride monomer, the water-dispersible polymer, and the solid particles, the reaction liquid contains the water-dispersed polymer in an amount of 5 parts by mass or more and 30 parts by mass or less relative to a total of 100 parts by mass of the vinyl chloride monomer, the water-dispersed polymer, and the solid particles, the reaction liquid contains 50 parts by mass or more and 65 parts by mass or less of the solid particles relative to a total of 100 parts by mass of the vinyl chloride monomer, the water-dispersible polymer, and the solid particles, A method for producing an aqueous dispersion.

16. The step of polymerizing the vinyl chloride monomer comprises: (i) The concentration of the surfactant having a molecular weight of 1,000 or less in the reaction solution is 100 g / m ３ (ii) polymerizing the vinyl chloride monomer under the following conditions: (i) a ratio of the mass of a surfactant having a molecular weight of 1000 or less to the mass of the vinyl chloride monomer is less than 0.001% by mass; Including, 16. A method for producing the aqueous dispersion of claim 15.