Composition

Abstract

To provide a composition containing a polymer particle excellent in storage stability, and capable of making a film excellent in scratch resistance and adhesion.SOLUTION: A composition pertaining to the present invention contains: a polymer particle (A); at least one compound (B) selected from the group consisting of phosphoric acid esters having a 10-18C alkyl group and salts thereof; and a liquid medium (C), wherein the polymer particle (A) contains a polymer having a repeating unit derived from methyl (meth)acrylate, and a content ratio of the compound (B) is 5 to 30 pts.mass to 100 pts.mass of the polymer particle (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition containing polymer particles. [Background technology]

[0002] Compositions containing polymer particles such as latex are widely used as binders in fields such as paper coating, carpet backsizing, wood products such as plywood and veneer, battery electrodes, and tire cords (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-124473 [Patent Document 2] International Publication No. 2021 / 006211 Summary of the Invention [Problem to be solved by the invention]

[0004] A composition containing such polymer particles is used in a mixture with other components in various applications such as those described above. For example, when a mixture of the composition and other components is applied to a substrate to form a coating film, scratch resistance is required to prevent scratches even when the surfaces of the substrates on which the film is formed are rubbed against each other when the substrates are stacked and stored. Furthermore, when a mixture of the composition and other components is applied to a substrate to form a coating film, adhesion is required to prevent the coating film from peeling from the substrate. Furthermore, the composition is required to have storage stability such that the physical properties remain almost unchanged even after long-term storage.

[0005] Some aspects of the present invention provide a composition containing polymer particles that has excellent storage stability and can form a film that is excellent in scratch resistance and adhesion. [Means for solving the problem]

[0006] One aspect of the composition of the present invention is Polymer particles (A), at least one compound (B) selected from the group consisting of phosphate esters and salts thereof having an alkyl group having 10 to 18 carbon atoms; A liquid medium (C); A composition comprising: the polymer particles (A) contain a polymer having a repeating unit derived from methyl (meth)acrylate, The content of the compound (B) is 5 to 30 parts by mass relative to 100 parts by mass of the polymer particles (A).

[0007] In one embodiment of the composition, The compound (B) may be one selected from the group consisting of phosphoric acid monoesters, phosphoric acid diesters, and salts thereof.

[0008] In any of the above-described embodiments of the composition, The compound (B) may be a compound represented by the following general formula (1). (R 1 O(AO) m ) n -PO(O - M + ) 3-n ·····(1) (In the above formula (1), R 1 represents an alkyl group having 10 to 18 carbon atoms, and a plurality of AOs each independently represent an alkyleneoxy group; m represents an integer of 0 to 10; n is an integer of 1 or 2; Represents a number. + represents a monovalent cation.)

[0009] In any of the above-described embodiments of the composition, The acid value of the polymer constituting the polymer particles (A) may be 50 to 130 mgKOH / g. [Effects of the Invention]

[0010] The composition according to the present invention has excellent storage stability and can produce a film that is excellent in scratch resistance and adhesion. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present invention will be described in detail below. Note that the present invention is not limited to the following embodiments, and various modifications are also included within the scope of the present invention.

[0012] In this specification, "(meth)acrylic" refers to "acrylic" or "methacrylic".

[0013] In this specification, a numerical range described using "X to Y" means that the range includes the numerical value X as the lower limit and the numerical value Y as the upper limit.

[0014] 1. Composition A composition according to one embodiment of the present invention comprises polymer particles (A) (hereinafter also referred to as "component (A)"), at least one compound (B) (hereinafter also referred to as "component (B)") selected from the group consisting of phosphate esters and salts thereof having an alkyl group having 10 to 18 carbon atoms, and a liquid medium (C) (hereinafter also referred to as "component (C)"), wherein the polymer particles (A) contain a polymer having a repeating unit derived from methyl (meth)acrylate, and the content of the compound (B) is 5 to 30 parts by mass per 100 parts by mass of the polymer particles (A). Components that may be contained in the composition according to this embodiment will be described in detail below.

[0015] 1.1. Polymer particles (A) The composition according to this embodiment contains polymer particles (A). The polymer particles (A) contain a polymer having repeating units derived from methyl (meth)acrylate. The composition according to this embodiment is preferably in the form of a latex in which the polymer particles (A) are dispersed in a liquid medium (C).

[0016] Hereinafter, the repeating units contained in the polymer constituting the polymer particles (A), the physical properties of the polymer constituting the polymer particles (A), and the synthesis method will be described in that order.

[0017] 1.1.1. Repeating Unit The polymer constituting the polymer particles (A) contains a repeating unit (Ma) (hereinafter also referred to as "repeating unit (Ma)") derived from methyl (meth)acrylate. The polymer constituting the polymer particles (A) preferably further contains a repeating unit (Mb) (hereinafter also referred to as "repeating unit (Mb)") represented by the following general formula (2): [ka] (In formula (2), R 2 represents a hydrogen atom or a methyl group, and R 3 represents an alkyl group having 4 to 10 carbon atoms.

[0018] The content of the repeating unit (Ma) is preferably 20 to 95% by mass when the total of the repeating units contained in the polymer constituting the polymer particles (A) is taken as 100% by mass. The lower limit of the content of the repeating unit (Ma) is more preferably 30% by mass, and particularly preferably 40% by mass. The upper limit of the content of the repeating unit (Ma) is more preferably 90% by mass, and particularly preferably 85% by mass.

[0019] Specific examples of the monomer that provides the repeating unit (Mb) include alkyl (C4-C10) (meth)acrylate esters such as n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, and decyl (meth)acrylate, and the monomer may be one or more selected from these. Of these alkyl (C4-C10) (meth)acrylate esters, one or more selected from n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred.

[0020] The content of the repeating unit (Mb) is preferably 1 to 75% by mass, when the total of the repeating units contained in the polymer constituting the polymer particles (A) is 100% by mass. The lower limit of the content of the repeating unit (Mb) is more preferably 3% by mass, and particularly preferably 5% by mass. The upper limit of the content of the repeating unit (Mb) is more preferably 70% by mass, and particularly preferably 60% by mass.

[0021] The polymer constituting the polymer particles (A) may contain, in addition to the repeating units (Ma) and (Mb), repeating units derived from other monomers copolymerizable therewith. Examples of such repeating units include repeating units derived from α,β-unsaturated nitrile compounds, repeating units derived from aromatic vinyl compounds, repeating units derived from unsaturated carboxylic acids, repeating units derived from unsaturated carboxylic acid esters (excluding the repeating units (Ma) and (Mb)), and repeating units derived from α,β-unsaturated amides.

[0022] Specific examples of the α,β-unsaturated nitrile compound include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile, vinylidene cyanide, etc., and the compound may be one or more selected from these. Among these, the compound may be one or more selected from acrylonitrile and methacrylonitrile, and more preferably acrylonitrile.

[0023] The content of the repeating unit derived from the α,β-unsaturated nitrile compound is 35% by mass when the total amount of the repeating units contained in the polymer constituting the polymer particles (A) is taken as 100% by mass. It is preferably 10% by mass or less, and more preferably 3 to 15% by mass.

[0024] Specific examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, 1-ethyl-2-vinylbenzene, divinylbenzene, sodium p-styrenesulfonate, etc., and the aromatic vinyl compound may be one or more selected from these. Of the above, styrene is particularly preferred as the aromatic vinyl compound.

[0025] The content of repeating units derived from aromatic vinyl compounds is preferably 5 to 45 mass%, and more preferably 10 to 30 mass%, when the total amount of repeating units contained in the polymer constituting the polymer particles (A) is taken as 100 mass%.

[0026] Specific examples of unsaturated carboxylic acids include monocarboxylic acids or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and the unsaturated carboxylic acid may be one or more selected from these. In particular, one or more selected from acrylic acid, methacrylic acid, and itaconic acid is preferred.

[0027] The content of the repeating units derived from the unsaturated carboxylic acid is preferably 0.1 to 20 mass%, and more preferably 0.5 to 15 mass%, when the total of the repeating units contained in the polymer constituting the polymer particles (A) is taken as 100 mass%.

[0028] Examples of the unsaturated carboxylic acid ester include (meth)acrylic acid esters other than methyl (meth)acrylate and alkyl (C4-C10) (meth)acrylate esters. Specific examples of such (meth)acrylic acid esters include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, benzyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, ethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate, and the like.

[0029] The content of the repeating units derived from the unsaturated carboxylic acid ester (excluding the repeating units (Ma) and (Mb)) is preferably 0.1 to 10 mass%, and more preferably 0.5 to 5 mass%, when the total of the repeating units contained in the polymer constituting the polymer particles (A) is taken as 100 mass%.

[0030] Specific examples of the α,β-unsaturated amide compound include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, and N,N-diethyl(meth)acrylamide, and the compound may be one or more selected from these.

[0031] The content ratio of the repeating unit derived from the α,β-unsaturated amide compound is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, based on 100% by mass of the total repeating units contained in the polymer constituting the polymer particles (A).

[0032] 1.1.2. Physical properties of the polymer 1.1.2.1. Acid value of the polymer The acid value of the polymer constituting the polymer particles (A) is a value measured in accordance with "JIS K 0070:1992", and is preferably 50 to 130 mgKOH / g, more preferably 100 mgKOH / g. The acid value of the polymer constituting the polymer particles (A) can be adjusted by the amount of the monomer having an acid group constituting the polymer, etc. When the acid value of the polymer constituting the polymer particles (A) is within the above range, the polymer particles have excellent storage stability, and when the composition is applied onto a substrate to form a coating film or the like, strong intermolecular interactions such as hydrogen bonds between the polymer particles (A) and between the polymer particles (A) and the component (B) can form a tough coating film. As a result, when the formed substrates are stacked and stored and the surfaces rub against each other, it may be possible to prevent scratches from occurring.

[0033] 1.1.2.2. Tetrahydrofuran (THF) insoluble matter The THF insoluble matter of the polymer constituting the polymer particles (A) is preferably 60% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on 100% by mass of the polymer. The THF insoluble matter serves as an index for the solvent resistance and water resistance of the resulting coating film. Therefore, if the THF insoluble matter is within the above range, it is considered that the water resistance when a coating film is formed using the composition according to this embodiment is good. The THF insoluble matter is measured by the following method.

[0034] <Measurement method of THF insoluble matter> 0.15 g of the dried polymer film constituting the polymer particles (A) is added to 50 mL of tetrahydrofuran and stirred for 16 hours to obtain a liquid. Next, the liquid is filtered using filter paper equivalent to JIS P3801 Type 2, 10 mL of the filtrate is collected and dried, and the insoluble content (gel fraction) is calculated from the dried mass, and this calculated value is the THF insoluble content.

[0035] 1.1.2.3.Number average particle size The number average particle diameter of the polymer particles (A) is preferably in the range of 30 nm to 600 nm, more preferably in the range of 40 nm to 200 nm. When the number average particle diameter of the polymer particles (A) is in the above range, the surface of the resulting coating film becomes smooth, and a coating film with excellent scratch resistance can be produced.

[0036] The number-average particle size of the polymer particles (A) is the particle size (D50) value at which the cumulative frequency of the number of particles, starting from the smallest particle, reaches 50% when the particle size distribution is measured using a particle size distribution analyzer based on the light scattering method. Examples of such particle size distribution analyzers include the Coulter LS230, LS100, and LS13 320 (all manufactured by Beckman Coulter, Inc.) and the FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.). These particle size distribution analyzers can evaluate not only the primary particles of polymer particles but also secondary particles formed by aggregation of the primary particles. Therefore, the particle size distribution measured by these particle size distribution analyzers can be used as an indicator of the dispersion state of the polymer particles.

[0037] 1.1.2.4.Transition Temperature The transition temperature of the polymer constituting the polymer particles (A) is preferably in the range of -20°C to 150°C, more preferably in the range of -10°C to 135°C, when measured by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

[0038] 1.1.3. Polymer synthesis method The method for synthesizing the polymer constituting the polymer particles (A) is not particularly limited, but they can be easily prepared, for example, by the emulsion polymerization process described below.

[0039] The emulsion polymerization step is carried out by emulsifying and dispersing the monomer components, an emulsifier, a polymerization initiator, and a chain transfer agent in an aqueous medium by stirring, followed by radical polymerization. Each material used in the emulsion polymerization step will be described below.

[0040] Examples of the monomer component used in the emulsion polymerization step include, in addition to methyl (meth)acrylate, alkyl (C4-C10) (meth)acrylate esters, α,β-unsaturated nitrile compounds, aromatic vinyl compounds, unsaturated carboxylic acids, unsaturated carboxylic acid esters other than methyl (meth)acrylate and alkyl (C4-C10) (meth)acrylate esters, and α,β-unsaturated amide compounds.

[0041] In 100% by mass of all monomer components, the content of methyl (meth)acrylate is preferably from 20 to 95% by mass, more preferably from 30 to 90% by mass, and particularly preferably from 40 to 85% by mass.

[0042] In 100% by mass of all monomer components, the content of (meth)acrylic acid alkyl (C4-C10) ester is preferably 1 to 75% by mass, more preferably 3 to 70% by mass, and particularly preferably 5 to 60% by mass.

[0043] Specific examples of the emulsifier include anionic surfactants such as sulfate salts of higher alcohols, aliphatic sulfates, alkylbenzenesulfonates, alkyldiphenyletherdisulfonates, aliphatic sulfonates, aliphatic carboxylates, aliphatic phosphate salts, aliphatic phosphate salts, dehydroabietic acid salts, naphthalenesulfonic acid-formalin condensates, sulfate salts or phosphate salts having a (poly)alkoxy structure, and polymerizable ether sulfate-type ammonium salts; nonionic surfactants such as alkyl esters of polyethylene glycol, alkylphenyl ethers of polyethylene glycol, and alkyl ethers of polyethylene glycol; and fluorine-based surfactants such as perfluorobutylsulfonates, perfluoroalkyl group-containing phosphate esters, perfluoroalkyl group-containing carboxylates, and perfluoroalkylethylene oxide adducts. One or more selected from these may be used.

[0044] Specific examples of polymerization initiators include water-soluble polymerization initiators such as lithium persulfate, potassium persulfate, sodium persulfate, ammonium persulfate, and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] tetrahydrate; and oil-soluble polymerization initiators such as cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide, acetyl peroxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, azobisisobutyronitrile, and 1,1'-azobis(cyclohexanecarbonitrile). Among these, potassium persulfate, sodium persulfate, ammonium persulfate, cumene hydroperoxide, or tert-butyl hydroperoxide is preferred. The proportion of the polymerization initiator used is not particularly limited, but should be determined appropriately taking into account the monomer composition, pH of the polymerization reaction system, and the combination of other additives.

[0045] Specific examples of the chain transfer agent include alkyl mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, tert-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, and n-stearyl mercaptan; xanthogen compounds such as dimethyl xanthogen disulfide and diisopropyl xanthogen disulfide; terpinolene, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetramethylthiuram monosulfide. Thiuram compounds such as sulfides; phenolic compounds such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; allyl compounds such as allyl alcohol; halogenated hydrocarbon compounds such as dichloromethane, dibromomethane, and carbon tetrabromide; vinyl ether compounds such as α-benzyloxystyrene, α-benzyloxyacrylonitrile, and α-benzyloxyacrylamide, as well as triphenylethane, pentaphenylethane, acrolein, methacrylonitrile, and methylacrolein. Examples of the thioglycolic acid include thiomalic acid, 2-ethylhexyl thioglycolate, thiomalic acid, 2-ethylhexyl thioglycolate, and α-methylstyrene dimer, and one or more selected from these may be used.

[0046] The emulsion polymerization step is preferably carried out under conditions of a polymerization temperature of 40 to 80°C and a polymerization time of 2 to 4 hours.

[0047] After the emulsion polymerization is completed, it is preferable to neutralize the dispersion by adding a neutralizing agent so that the pH of the dispersion is about 5 to 10. The neutralizing agent used is not particularly limited, but examples include metal hydroxides such as sodium hydroxide and potassium hydroxide, ammonia, and amine compounds. Setting the pH of the dispersion in the range of 5 to 10 improves the blend stability of the dispersion, and the pH of the dispersion is preferably 6 to 9, and more preferably 7 to 8.5. Setting the total solids concentration in the emulsion polymerization step to 50% by mass or less allows the reaction to proceed with good dispersion stability. The total solids concentration in the emulsion polymerization step is preferably 45% by mass or less, and more preferably 40% by mass or less. Furthermore, concentration after the neutralization treatment can further improve particle stability while achieving a high solids concentration.

[0048] 1.2. Compound (B) The composition according to this embodiment contains at least one compound (B) selected from the group consisting of phosphoric acid esters having an alkyl group having 10 to 18 carbon atoms and salts thereof.

[0049] Generally, "phosphate ester" is a general term for compounds having a structure in which all or some of the three hydrogen atoms in phosphoric acid (O=P(OH)3) are substituted with alkyl groups. In component (B), the substituted alkyl groups have 10 to 18 carbon atoms, and preferably 11 to 15 carbon atoms.

[0050] Furthermore, component (B) is preferably at least one compound selected from the group consisting of phosphoric acid monoesters, phosphoric acid diesters, and salts thereof. When component (B) contains both phosphoric acid monoesters and phosphoric acid diesters, the content ratios thereof are not particularly limited.

[0051] The component (B) is more preferably a compound represented by the following general formula (1). (R 1 O(AO) m ) n -PO(O - M + )3-n ·····(1) (In the above formula (1), R 1 represents an alkyl group having 10 to 18 carbon atoms, and a plurality of AOs each independently represents an alkyleneoxy group. m represents an integer of 0 to 10, and n represents an integer of 1 or 2. M + represents a monovalent cation.)

[0052] Specific examples of component (B) include monoalkyl (C10-C18) phosphate, alkyl (C10-C18) ether phosphate, polyoxyethylene alkyl (C10-C18) ether phosphate, polyoxyethylene alkyl (C10-C18) phenyl ether phosphate, etc. Here, "alkyl (C10-C18)" refers to an alkyl group having 10 to 18 carbon atoms. Among these, phosphate monoesters such as monodecyl phosphate, monoundecyl phosphate, monolauryl phosphate, monotridecyl phosphate, monotetradecyl phosphate, monohexadecyl phosphate, monooctadecyl phosphate, polyoxyethylene monolauryl ether phosphate, polyoxyethylene monotetradecyl ether phosphate, polyoxyethylene monohexadecyl ether phosphate, and polyoxyethylene monooctadecyl ether phosphate; didecyl phosphate, diundecyl phosphate, dilauryl phosphate, ditridecyl phosphate, ditetradecyl phosphate, dihexadecyl phosphate, dioctadecyl phosphate, polyoxyethylene dilauryl ether phosphate, polyoxyethylene ditetradecyl ether phosphate, polyoxyethylene dihexadecyl ether phosphate, and polyoxyethylene dioctadecyl ether phosphate are particularly preferred. It is particularly preferable that the phosphate diester be at least one selected from the group consisting of phosphate diesters such as phosphate diesters of carboxylic acid and the like; and salts thereof. These may be used alone or in combination of two or more.

[0053] The content of component (B) in the composition according to this embodiment is 5 to 30 parts by mass, and preferably 10 to 20 parts by mass, per 100 parts by mass of component (A). When the content of component (B) in the composition according to this embodiment is within this range, the adhesion of a coating film prepared using the composition is improved. Furthermore, when the content of component (B) in the composition according to this embodiment is within this range, component (B) imparts adhesion between the substrate and the coating film during film formation, making it possible to prepare a film with excellent scratch resistance.

[0054] The component (B) in the composition according to this embodiment may be the same as the component commonly used as an emulsifier when synthesizing the polymer particles (A) by emulsion polymerization. Therefore, it is assumed that the dispersion of the polymer particles (A) synthesized by emulsion polymerization contains a trace amount of the component (B). In contrast, in the present invention, the component (B) is added in an amount significantly exceeding the amount of emulsifier used in emulsion polymerization during the preparation of the composition, resulting in a content of the component (B) significantly greater than the content used in emulsion polymerization.

[0055] 1.3. Liquid Medium (C) The composition according to this embodiment contains a liquid medium (C). The liquid medium (C) is preferably an aqueous medium containing water. The aqueous medium may contain a non-aqueous medium other than water. Examples of such non-aqueous medium include amide compounds, hydrocarbons, alcohols, ketones, esters, amine compounds, lactones, sulfoxides, and sulfone compounds, and one or more selected from these may be used. When the liquid medium (C) contains water and a non-aqueous medium, it is preferable that the total mass of the liquid medium (C) is 100% by mass, and more preferably 90% by mass or more of the liquid medium (C) is water. By using an aqueous medium as the liquid medium (C) in the composition according to this embodiment, the degree of adverse impact on the environment is reduced and the safety for handling workers is increased.

[0056] The content of the non-aqueous medium in the aqueous medium is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably substantially free of the non-aqueous medium, based on 100% by mass of the aqueous medium. Here, "substantially free of the non-aqueous medium" means that the non-aqueous medium is not intentionally added as a liquid medium, and the composition may contain a non-aqueous medium that is inevitably mixed in when preparing the composition.

[0057] 1.4. Other Additives The composition according to the present embodiment may contain additives other than the above-mentioned components, such as thickeners, fillers, preservatives, and pH adjusters, as needed.

[0058] <Thickener> Examples of thickeners include cellulose compounds such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose; ammonium salts or alkali metal salts of the above cellulose compounds; polycarboxylic acids such as poly(meth)acrylic acid and modified poly(meth)acrylic acid; alkali metal salts of the above polycarboxylic acids; polyvinyl alcohol (co)polymers such as polyvinyl alcohol, modified polyvinyl alcohol, and ethylene-vinyl alcohol copolymers; and water-soluble polymers such as saponified copolymers of vinyl esters with unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, and fumaric acid. Among these, alkali metal salts of carboxymethyl cellulose and poly(meth)acrylic acid are particularly preferred. Alkali metal salts are particularly preferred.

[0059] Commercially available thickeners include alkali metal salts of carboxymethylcellulose such as CMC1120, CMC1150, CMC2200, CMC2280, and CMC2450 (all manufactured by Daicel Corporation).

[0060] When the composition according to this embodiment contains a thickener, the amount of the thickener used is preferably 5% by mass or less, and more preferably 0.1 to 3% by mass, based on the total solid content of the composition.

[0061] <Filler The composition according to this embodiment may improve the hardness of the coating film when formed into a coating film by containing a filler. Examples of the filler include organic fillers and inorganic fillers. Specific examples of the organic filler include polyamide fine particles such as nylon 6, nylon 12, and nylon 66; fluorine-based fine particles such as tetrafluoroethylene and vinylidene fluoride; olefin-based fine particles such as polyethylene and polypropylene; polyester-based fine particles such as polyethylene terephthalate and polyethylene naphthalate; crosslinked particles such as divinylbenzene and polyfunctional acrylate; and rubber fine particles such as natural rubber, isoprene rubber, and acrylic rubber. Specific examples of the inorganic filler include fused spherical silica, fumed silica, sol-gel silica, aluminum oxide, aluminum hydroxide, calcium carbonate, calcium hydroxide, barium sulfate, barium carbonate, magnesium oxide, magnesium hydroxide, and other inorganic fillers derived from minerals such as talc and mica. One or more of these can be used.

[0062] <Preservative The composition according to this embodiment can suppress the growth of bacteria, mold, etc. and the generation of foreign substances when the composition is stored by containing a preservative. Specific examples of the preservative include 1,2-benzisothiazolin-3-one, 2-methyl-4,5-trimethylene-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, N-n-butyl-1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, etc. One or more of these can be used.

[0063] <pH adjuster The composition according to this embodiment may be adjusted to a pH of 5 to 9 by adding a pH adjuster. Adjusting the pH to 5 to 9 may improve the dispersion stability of the polymer particles (A) and may result in excellent storage stability. Examples of pH adjusters include acidic compounds such as hydrochloric acid, phosphoric acid, sulfuric acid, acetic acid, and formic acid; and basic compounds such as potassium hydroxide, ethylenediamine, monoethanolamine, TMAH (tetramethylammonium hydroxide), TEAH (tetraethylammonium hydroxide), and ammonia.

[0064] In the present invention, pH refers to hydrogen ion exponent, and its value can be measured using a commercially available pH meter (for example, a tabletop pH meter manufactured by Horiba, Ltd.) under conditions of 25°C and 1 atmosphere.

[0065] 1.5. Method for producing the composition The composition according to this embodiment may be prepared by mixing the above-mentioned components, and may be prepared, for example, by the method described in JP-A-2007-332202.

[0066] 2. Working Example The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0067] 2.1. Preparation of dispersion containing polymer particles (A) 2.1.1. Preparation of Dispersion P-1 After thoroughly replacing the inside of a 0.5 L separable flask with nitrogen, 150.0 parts by mass of ion-exchanged water and 0.3 parts by mass of ammonium persulfate (APS) were added. The internal temperature was adjusted to 80°C with stirring. In a separate container, 50.0 parts by mass of ion-exchanged water, 48.0 parts by mass of methyl methacrylate (MMA), 42.0 parts by mass of butyl acrylate (BA), 10.0 parts by mass of methacrylic acid (MAA), and 1 part by mass of SR-1025 (manufactured by ADEKA Corporation, trade name "ADEKA REASOAP SR-1025", ammonium salt of α-sulfo-ω-(1-alkoxy)methyl-2-(2-propenyloxy)ethoxy-poly(oxy-1,2-ethanediyl)) were mixed and stirred to form an emulsion. The resulting emulsion was continuously added dropwise to the reaction vessel over a period of 3 hours. After the dropwise addition was completed, the mixture was stirred at 80°C for another 3 hours and then cooled to 40°C. 1.1 parts by mass of ammonia (manufactured by Taisei Kako Co., Ltd., product name "25% aqueous ammonia") was added, and ion-exchanged water was added so that the polymer particle content was 30% by mass, to obtain Dispersion P-1. The acid value of the polymer particles contained in Dispersion P-1 thus obtained was measured in accordance with JIS K 0070:1992. The results are shown in Table 1.

[0068] 2.1.2. Preparation of Dispersions P-2 to P-4 Dispersions P-2, P-3, and P-4 containing 30% by mass of polymer particles were obtained in the same manner as in "2.1.1. Preparation of Dispersion P-1" above, except that the types and amounts of monomer, polymerization initiator, and emulsifier were changed as shown in Table 1 below.

[0069] 2.2. Examples 1 to 8 and Comparative Examples 1 to 5 2.2.1. Preparation of the Composition The components were mixed to obtain the content ratios shown in Tables 2 and 3 below, and water was added so that the total amount of the components shown in Tables 2 and 3 below was 20 mass %, thereby preparing the compositions of each example and comparative example.

[0070] 2.2.2. Evaluation of scratch resistance When a coating film is produced by applying a mixture of the composition and other components to a substrate, the substrates on which the film is formed may be stacked and stored, where they may be rubbed against each other, causing scratches on the coating surface and making the film unusable. For this reason, the scratch resistance of the coating film was evaluated using the following method. (Evaluation method) 10 g of Texanol was added to 500 g of the composition prepared above and stirred to prepare a composition for evaluating scratch resistance. The composition for evaluation was then applied to a paper substrate (manufactured by Kokuyo Co., Ltd., product name "KJ-M16A4") to a film thickness of 40 μm and dried at 80°C for 5 minutes to prepare an evaluation sample. The coating film of this evaluation sample was scratched with an HB pencil using an electric pencil scratch hardness tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd., product name "553-M-1"). The condition of the coating film was visually observed and evaluated according to the following criteria. The results are shown in Tables 2 and 3 below. (Evaluation criteria) AA: No peeling of the coating film is observed, and therefore it is judged to be very good. A: The peeling of the coating is less than 20% of the scratched area, so it is judged to be good. B: The peeling of the coating film is 20% or more but less than 50% of the scratched area, so it is judged to be somewhat poor. C: The coating film peeled off in 50% or more of the scratched area, and therefore the product was judged to be unsuitable for practical use and was therefore deemed to be defective.

[0071] 2.2.3. Evaluation of adhesion When a coating film is produced by applying a mixture of the composition and other components to a substrate, the substrates on which the film is formed may be stacked and stored, where they may rub against each other, causing the coating surface to peel off, making the product unusable for practical use. One cause of peeling is thought to be insufficient adhesion between the substrate and the coating film. For this reason, the adhesion between the substrate and the coating film was evaluated using the following method. (Evaluation method) 10 g of Texanol was added to 500 g of the composition prepared above and stirred to prepare a composition for evaluating adhesion. The composition for evaluation was then applied to a paper substrate (manufactured by Kokuyo Co., Ltd., product name "KJ-M16A4") to a film thickness of 40 μm and dried at 80°C for 5 minutes to prepare an evaluation sample. Cellophane tape (manufactured by Nichiban Co., Ltd.) was applied to this evaluation sample, rubbed with a finger, and then the cellophane tape was peeled off. The condition of the coating film in this area was observed and evaluated according to the following criteria. The results are shown in Tables 2 and 3 below. (Evaluation criteria) AA: No peeling of the coating film is observed, and therefore it is judged to be very good. A: The peeling of the coating is less than 20% of the tape peeled area, so it is judged to be good. B: Peeling of the coating film was 20% or more but less than 50% of the tape peeled area, so it was judged to be slightly poor. C: The coating film peeled off in 50% or more of the tape peeled area, and therefore the product was judged to be unsuitable for practical use and was therefore deemed to be defective.

[0072] 2.2.4. Evaluation of storage stability Generally, compositions such as those of the present invention are stored in large quantities in factories in preparation for use. Strict temperature control of the storage environment of the composition may not be possible due to cost considerations, and in summer, the composition is often exposed to an environment of around 40°C due to temperature changes. Therefore, it is required that the physical properties of the composition do not change significantly under such storage conditions. Therefore, the storage stability of the composition was evaluated by the following method, using the change in viscosity of the composition as an index of the change in physical properties. (Evaluation method) The composition prepared above was allowed to stand at 50°C for 30 days, and then returned to 25°C. The viscosity was measured using a viscosity measuring device (manufactured by Toki Sangyo Co., Ltd., model number "RE-85L"), and the rate of change in viscosity was calculated using the following formula. The evaluation criteria were as follows. The results are shown in Tables 2 and 3 below. Viscosity change rate (%) = [(viscosity when the composition is stored at 50°C for 30 days and then returned to 25°C) - (viscosity of the composition immediately after preparation)] / (viscosity of the composition immediately after preparation) x 100 (Evaluation criteria) A: The viscosity change rate is less than ±20%, so the storage stability is judged to be good. B: The viscosity change rate is ±20% or more, and the storage stability is judged to be poor.

[0073] 2.3.Evaluation Results The components used in preparing dispersions P-1 to P-4 containing polymer particles (A) and the acid values of the polymer particles are shown in Table 1. Tables 2 and 3 show the compositions and evaluation results of the compositions used in each example and comparative example.

[0074] [Table 1]

[0075] [Table 2]

[0076] [Table 3]

[0077] The abbreviations for each component in Tables 1 to 3 above represent the following products or reagents. <Monomer> MMA: Methyl methacrylate (manufactured by Mitsubishi Chemical Corporation, product name "Acryester M") BA: Butyl acrylate (manufactured by Mitsubishi Chemical Corporation, product name "Butyl acrylate") MAA: Methacrylic acid (manufactured by Mitsubishi Chemical Corporation, product name "MAA") <Polymerization initiator> APS: Ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc., product name "Ammonium persulfate") <Emulsifier> PDP: Potassium dodecyl phosphate (Takemoto Yushi Co., Ltd., product name "JAS-101") Number of carbon atoms in alkyl group = 12) SR-1025: (Manufactured by ADEKA Corporation, trade name "ADEKA REASOAP SR-1025", ammonium salt of α-sulfo-ω-(1-alkoxy)methyl-2-(2-propenyloxy)ethoxy-poly(oxy-1,2-ethanediyl)) <Compound (B)> PDP: Potassium dodecyl phosphate (manufactured by Takemoto Oil & Fat Co., Ltd., product name "JAS-101", alkyl group carbon number = 12) RD-510Y: Polyoxyethylene lauryl ether phosphate (manufactured by Toho Chemical Industry Co., Ltd., trade name "Phosphanol RD-510Y", alkyl group carbon number = 12) OP: Oleyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., product name "JP-518-O", number of carbon atoms in the alkyl group = 18) <Other additives> 2EP: 2-ethylhexyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., product name "JP-508", number of carbon atoms in the alkyl group = 8) TP: Tetracosyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., product name "JP-524-R", number of carbon atoms in the alkyl group = 24) SDS: Sodium dodecyl sulfate (Kao Corporation, product name "EMAL 2FG", alkyl group carbon number = 12)

[0078] The evaluation results in Tables 2 and 3 above show that the compositions according to the present invention shown in Examples 1 to 8 have excellent storage stability and can produce films with excellent scratch resistance and adhesion. In contrast, the compositions shown in Comparative Examples 1 and 2 contain less than 5 parts by mass or more than 30 parts by mass of component (B) per 100 parts by mass of polymer particles (A), and are found to not satisfy all of the storage stability, scratch resistance, and adhesion. Furthermore, the compositions shown in Comparative Examples 3 to 5 contain a component similar to component (B), but are found to not satisfy all of the storage stability, scratch resistance, and adhesion.

[0079] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as those described in the embodiments (for example, configurations with the same function, method, and result, or configurations with the same purpose and effect). The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

Claims

1. Polymer particles (A), at least one compound (B) selected from the group consisting of phosphate esters and salts thereof having an alkyl group having 10 to 18 carbon atoms; A liquid medium (C); A composition comprising: the polymer particles (A) contain a polymer having a repeating unit derived from methyl (meth)acrylate, The composition, wherein the content of the compound (B) is 5 to 30 parts by mass per 100 parts by mass of the polymer particles (A).

2. The composition according to claim 1, wherein the compound (B) is one selected from the group consisting of phosphoric acid monoesters, phosphoric acid diesters, and salts thereof.

3. The composition according to claim 1 or 2, wherein the compound (B) is a compound represented by the following general formula (1): (R １ O(AO) ｍ ) ｎ -PO(O － M ＋ ) ３－ｎ ・・・・・(1) (In the above formula (1), R １ represents an alkyl group having 10 to 18 carbon atoms, and each of the multiple AOs independently represents an alkyleneoxy group. m represents an integer of 0 to 10, and n represents an integer of 1 or 2. M ＋ represents a monovalent cation.)

4. 3. The composition according to claim 1, wherein the acid value of the polymer constituting the polymer particles (A) is 50 to 130 mgKOH / g.

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