METHOD FOR PREVENTING DUST GENERATION AND / OR INCREASED HUMIDITY IN OUTDOOR PILES

Abstract

A method for preventing dust generation from and / or moisture increase in an open-air pile, comprising spraying an O / W emulsion containing acrylic-based resin and polyvinyl alcohol-based resin onto the open-air pile.

Description

1 / 21 “METHOD FOR PREVENTING DUST GENERATION AND / OR INCREASE IN HUMIDITY IN OUTDOOR PILES” Technical Field

[0001] The present invention relates to a method for preventing the generation of dust and / or increased humidity in outdoor piles. Antecedent Technique

[0002] Dusts such as coal, iron ore, slag, dust, wood chips, wood shavings, paper slurry, and the like are stockpiled outdoors in steel mills, power plants, pulp and paper mills, and other facilities. Outdoor stockpiled dust generates dust pollution, which causes environmental problems. Furthermore, heavy rainfall or similar events can trigger landslides, coal runoff (a phenomenon in which stacked coal flows and collapses due to increased moisture content, causing the coal to become a liquid suspension), and other issues. Additionally, when it rains, for example, rainwater permeates the dust and increases its moisture content. The increased moisture content of the stacked dust causes the dust to consume extra energy to evaporate moisture when used as fuel, resulting in significant economic losses and increased CO2 emissions.Additionally, when the powder piled up outdoors is coal as a raw material, it has several adverse effects on the coke manufacturing process.

[0003] Thus, techniques to suppress the increase in moisture content of powder stacked outdoors are needed.

[0004] PTL 1 discloses the use of an acrylic-based emulsion resin as a hydrophobic treatment agent for an outdoor pile. The hydrophobic treatment agent is sprayed, applied, or mixed with the pile to form hydrophobic parts on the surface. Petition 870250073472, dated 08 / 20 / 2025, page 31 / 61 2 / 21 of the particles in the battery.

[0005] PTL 2 discloses the spraying of an emulsion resin solution containing polymer particles having particle sizes of 0.3 µm to 3 µm average particle diameter and 0.2 µm or more standard deviation onto an outdoor pile. The use of an emulsion resin solution, whose polymer particles have a large diameter and wide particle size distribution, as described above, forms thick, resistant coating films that are difficult to break on the pile, preventing dust generation or increased moisture in the outdoor pile. Patent Literature PTL 1: JP 01-38723 B PTL 2: JP 2013-203525 A Summary of the Invention Technical Problem

[0006] For the hydrophobic treatment agent disclosed in the PTL 1. The resulting film is weak and fragile, and may crack, allowing unwanted penetration of rainwater or similar substances.

[0007] The method disclosed in PTL 2 is also insufficient in terms of film strength, and the film cracks in some cases.

[0008] An object of the present invention is to provide a method for preventing dust generation and / or moisture buildup in an outdoor pile, which can increase the strength of the coating film produced from a coating agent to coat the particles of the outdoor pile and reliably prevent moisture buildup in the outdoor pile. Solution to the Problem

[0009] After careful analysis, the present inventors discovered that an emulsion containing acrylic-based resin and resin-based Petition 870250073472, dated 08 / 20 / 2025, p. 32 / 61 3 / 21 polyvinyl alcohol base can provide an enhanced coating film with film strength and reliably prevent moisture buildup in an outdoor stack. The present invention is based on these findings.

[0010] The present invention provides the following [1] to [9]: [1] A method for preventing the generation of dust and / or increased humidity in an outdoor pile, the method comprising spraying an O / W emulsion containing acrylic-based resin and polyvinyl alcohol-based resin onto an outdoor pile. [2] The method for preventing the generation of dust and / or increased humidity in an outdoor stack according to [1] above, wherein the acrylic-based resin is a styrene acrylic resin and / or a vinyl acetate acrylic resin. [3] The method for preventing the generation of dust and / or increased humidity in an outdoor pile according to [2] above, wherein styrene acrylic resin is a polymer of monomers, including a styrene-based monomer and one or more selected from the group consisting of (meth)acrylic acids and (meth)acrylic acid esters, the styrene-based monomer being styrene, the one or two or more selected from the group consisting of (meth)acrylic acids and (meth)acrylic acid esters being one or more selected from the group consisting of 2-ethylhexyl acrylate, methyl methacrylate, butyl acrylate and acrylic acid. [4] The method for preventing dust generation and / or increased humidity in an outdoor stack according to [2] or [3] above, wherein, in the total amount of styrene acrylic resin raw material monomers, the amount of styrene-based monomer mixed is from 5% to 70% by mass, and the amount of one or more selected from the group consisting of (meth)acrylic acids and (meth)acrylic acid esters mixed is from 30% to 95% by mass. Petition 870250073472, dated 08 / 20 / 2025, page 33 / 61 4 / 21 mass. [5] The method for preventing the generation of dust and / or increased humidity in an outdoor stack according to any of [2] to [4] above, wherein vinyl acetate acrylic resin is a polymer of monomers including vinyl acetate and one or more selected from the group consisting of (meth)acrylic acids and (meth)acrylic acid esters, the one or more selected from the group consisting of (meth)acrylic acids and (meth)acrylic acid esters being one or more selected from the group consisting of 2-ethylhexyl acrylate, methyl methacrylate, butyl acrylate and acrylic acid. [6] The method for preventing the generation of dust and / or the increase of humidity in an outdoor stack according to any of [2] to [5] above, wherein, in the total amount of vinyl acetate acrylic resin raw material monomers, the amount of vinyl acetate mixed is from 10% to 95% by mass, and the amount of one or more selected from the group consisting of (meth)acrylic acids and (meth)acrylic acid esters mixed is from 5% to 90% by mass. [7] The method for preventing dust generation and / or increased humidity in an outdoor stack according to any of [1] to [6] above, wherein the total amount of vinyl alcohol groups and vinyl ester groups in all structural units of the polyvinyl alcohol-based resin is 80% to 100% by mass. [8] The method for preventing the generation of dust and / or the increase of humidity in an outdoor pile according to any of [1] to [7] above, wherein the polyvinyl alcohol-based resin has a degree of polymerization with an average viscosity of 100 to 10,000. [9] The method for preventing the generation of dust and / or the increase of humidity in an outdoor pile according to any Petition 870250073472, dated 08 / 20 / 2025, pp. 34 / 61 5 / 21 one of [1] to [8] above, wherein the polyvinyl alcohol-based resin has a saponification degree of 70% to 95% by mol. Advantageous Effects of the Invention

[0011] The present invention can provide a method for preventing dust generation and / or moisture buildup in an outdoor pile, which can increase the strength of the coating film produced from a coating agent to coat the particles of the outdoor pile and reliably prevent moisture buildup in the outdoor pile. Description of the Modalities

[0012] The method according to the present invention for preventing the generation of dust and / or the increase of humidity in an outdoor pile will be described.

[0013] The term (met) acrylic used here refers to acrylic and methacrylic.

[0014] The term solids used here refers to the constituents, excluding the dispersion medium. Coating Agent for Outdoor Piles

[0015] The coating agent used in the present invention for an outdoor battery is an O / W emulsion containing acrylic-based resin and polyvinyl alcohol (also referred to as PVA).

[0016] The coating agent containing resin-based PVA, in addition to acrylic resin, can provide an improved film with greater strength and reliably prevent moisture buildup in an outdoor pile, compared to the case of one without PVA-based resin. The details of the reason for this are not known, but it is presumed to be as follows.

[0017] When a known coating agent containing acrylic-based resin but without PVA-based resin is added as a coating agent to an outdoor pile, a layer Petition 870250073472, dated 08 / 20 / 2025, page 35 / 61 A 6 / 21 coating made of acrylic-based resin is formed on the surface of the pile particles. However, the coating layer has low film strength and can crack, allowing rainwater or similar substances to penetrate.

[0018] In contrast, when the coating agent according to the present invention, which contains not only acrylic-based resin but also PVA-based resin, is added to an outdoor pile, a coating layer produced from acrylic-based resin is formed on the surface of the pile particles, and a protective layer produced from PVA-based resin is formed over the coating layer produced from acrylic-based resin. Furthermore, the acrylic-based resin and the PVA-based resin are firmly fused to increase the film's strength. Thus, the resulting film is unlikely to crack, preventing the penetration of rainwater or similar substances. Acrylic-based resin

[0019] An acrylic-based resin is a polymer of monomers including one or more monomers selected from the group consisting of (meth)acrylic acids and their esters.

[0020] The acrylic-based resin used herein may be a polymer of one or more monomers selected from the group consisting of (meth)acrylic acids and their esters, or a polymer of one or more monomers selected from the group consisting of (meth)acrylic acids and their esters and one or more other monomers.

[0021] Preferably, the acrylic-based resin is a styrene acrylic resin and / or a vinyl acetate acrylic resin. Styrene Acrylic Resin

[0022] A styrene acrylic resin refers to a polymer of monomers that includes a styrene-based monomer and one or more selected from the group consisting of (meth)acrylic acids and esters. Petition 870250073472, dated 08 / 20 / 2025, pp. 36 / 61 7 / 21 (meth)acrylic acid. Styrene-Based Monomer

[0023] Styrene-based monomers include styrene and styrene derivatives such as α-methylstyrene. The styrene-based monomer is preferably styrene. (Meth)acrylic Acids and (Meth)acrylic Acid Esters

[0024] (Meth)acrylic acids refer to acrylic acid and methacrylic acid.

[0025] (Meth)acrylic acid esters include alkyl esters of (meth)acrylic acid without special functional groups or cyclic structures, (meth)acrylic acid esters containing a hydroxyl group, (meth)acrylic acid esters containing a glycidyl group, (meth)acrylic acid esters containing an oxyalkylene group, (meth)acrylic acid esters containing an alicyclic structure, and (meth)acrylic acid esters containing an aromatic ring.

[0026] Examples of alkyl esters of (meth)acrylic acid without special functional groups or cyclic structures include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, 3-pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, heptyl (meth)acrylate, 2-heptyl (meth)acrylate, octyl, 2-octyl (meth)acrylate, (meth)acrylate of 2-ethylhexyl, (meth)acrylate of nonyl, (meth)acrylate of decyl, (meth)acrylate of undecyl and (meth)acrylate of dodecyl. Among these, the preferred ones are (meth)acrylate of butyl, (meth)acrylate of isobutyl, (meth)acrylate of t-butyl, (meth)acrylate of 2-ethylhexyl and (meth)acrylate of dodecyl from the point of view of water resistance and temporal stability.

[0027] Examples of (meth)acrylic acid esters containing a Petition 870250073472, dated 08 / 20 / 2025, pp. 37 / 61 8 / 21 hydroxy groups include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono(meth)acrylate, N-(2-hydroxyethyl)(meth)acrylamide, and allyl alcohol.

[0028] Examples of (meth)acrylic acid esters containing a glycidyl group include glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether.

[0029] Examples of (meth)acrylic acid esters containing an oxyalkylene group include diethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, polyethylene glycol polypropylene glycol mono(meth)acrylate, methoxydiethylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, phenoxydiethylene mono(meth)acrylate glycol, phenoxypolyethylene glycol mono(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate and polyethylene glycol di(meth)acrylate.

[0030] Examples of (meth)acrylic acid esters containing an alicyclic structure include cyclohexyl (meth)acrylate.

[0031] Examples of (meth)acrylic acid esters containing an aromatic ring include benzyl (meth)acrylate. Other Monomers

[0032] The monomers of the raw material of styrene acrylic resin may or may not include other monomers besides the monomers mentioned above.

[0033] These other monomers include monomers containing amide groups, vinyl acetate, and other monomers containing reactive functional groups.

[0034] Examples of monomers containing an amide group include N-vinylacetamide, (meth)acrylamide, diacetone (meth)acrylamide, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide and N-butyl(meth)acrylamide. Petition 870250073472, dated 08 / 20 / 2025, pp. 38 / 61 9 / 21 Combination Proportions

[0035] The amount of styrene-based monomer combination in the total amount of styrene acrylic resin raw material is preferably 5% to 70% by mass, more preferably 10% to 60% by mass, and even more preferably 10% to 50% by mass, but may be 20% to 50% by mass or 35% to 45% by mass.

[0036] The amount of acrylic monomer combination in the total amount of styrene acrylic resin raw material is preferably 30% to 95% by mass, more preferably 40% to 90% by mass, and even more preferably 50% to 90% by mass, but may be 50% to 80% by mass or 55% to 65% by mass.

[0037] The total combination of styrene-based monomer and acrylic monomer in the total amount of monomers in the styrene acrylic resin raw material is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and even more preferably 95% to 100% by mass, and may be 100% by mass. Vinyl Acetate Acrylic Resin

[0038] A vinyl acetate acrylic resin refers to a polymer of monomers including vinyl acetate and one or more selected from the group consisting of (meth)acrylic acids and (meth)acrylic acid esters. (Meth)acrylic Acids and (Meth)acrylic Acid Esters

[0039] The types of (meth)acrylic acids and (meth)acrylic acid esters are the same as those described above with respect to styrene acrylic resin. Other Monomers

[0040] The raw material monomers of acrylic resin Petition 870250073472, dated 08 / 20 / 2025, pp. 39 / 61 10 / 21 vinyl coatings may or may not include other monomers besides the monomers mentioned above.

[0041] The types of other monomers are the same as those described above with respect to styrene acrylic resin. Combination Proportions

[0042] The amount of vinyl acetate combined in the total amount of monomers of the vinyl acetate acrylic resin raw material is preferably from 10% to 95% by mass, more preferably from 15% to 90% by mass, still preferably from 20% to 90% by mass and even more preferably from 40% to 90% by mass, and may be from 60% to 90% by mass or from 75% to 85% by mass.

[0043] The amount of acrylic monomer combination in the total amount of monomers of the vinyl acetate acrylic resin raw material is preferably from 5% to 90% by mass, more preferably from 10% to 85% by mass, still preferably from 10% to 80% by mass and even more preferably from 10% to 60% by mass, and may be from 10% to 40% by mass, from 10% to 15% by mass or from 15% to 25% by mass.

[0044] The total combination of vinyl acetate and acrylic monomer in the total amount of monomers in the raw material of vinyl acetate acrylic resin is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and even more preferably 95% to 100% by mass, but may be 100% by mass. Other Resins

[0045] Acrylic-based resin may or may not include other acrylic-based resins besides styrene acrylic resin and vinyl acetate acrylic resin, but preferably does not include other acrylic-based resins other than styrene acrylic resin and vinyl acetate acrylic resin. Petition 870250073472, dated 08 / 20 / 2025, pages 40 / 61 11 / 21

[0046] The total amount of styrene acrylic resin and vinyl acetate acrylic resin in the acrylic-based resin is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and even more preferably 95% to 100% by mass. Polymerization Method for Acrylic-Based Resin

[0047] Acrylic-based resin can be synthesized by emulsion polymerization, suspension polymerization, bulk polymerization, solution polymerization, or similar methods. Preferably, acrylic-based resin is synthesized by emulsion polymerization of a mixture of monomers in the presence of a surfactant.

[0048] The acrylic-based resin is preferably in particle form when mixed with the coating agent. Therefore, after the acrylic-based resin is synthesized by solution polymerization, water, and optionally a surfactant, can be added, and the acrylic-based resin is transferred to an aqueous phase through a known method to form acrylic-based resin particles.

[0049] In the polymerization of acrylic-based resin, a polymerization initiator, a buffer, a chain transfer agent, a base compound and other additives may be used optionally. PVA-based resin

[0050] PVA-based resin is a resin that contains vinyl alcohol groups and vinyl ester groups as structural units. PVA-based resin may or may not contain other structural units, but preferably does not.

[0051] The total amount of vinyl alcohol groups and vinyl ester groups in all the structural units of the PVA-based resin is preferably 80% to 100% by mass, more preferably Petition 870250073472, dated 08 / 20 / 2025, pp. 41 / 61 12 / 21 mind of 90% to 100% in mass and even more preferably of 95% to 100% in mass.

[0052] The saponification degree of the PVA-based resin is preferably 70% to 95% by mol, more preferably 75% to 90% by mol, still preferably 80% to 90% by mol and even more preferably 85% to 90% by mol.

[0053] The degree of saponification used here refers to the percentage (% mol) of the amount in moles of vinyl alcohol groups relative to the total amount in moles of vinyl alcohol groups and vinyl ester groups in the PVA-based resin.

[0054] The degree of saponification can be measured according to a method specified in JIS K6726 (1994). For a degree of saponification of 70 mol% or less, it should be measured using a 1:1 mixture of water and methanol instead of the water used as solvent in the method above.

[0055] The average degree of polymerization (viscosity-average degree of polymerization) of PVA is not particularly limited, but is preferably from 100 to 10,000, more preferably from 200 to 5,000 and still preferably from 400 to 4,000 from the point of view of viscosity and solubility in water.

[0056] The average degree of polymerization (viscosity-average degree of polymerization) can be measured according to a method specified in JIS K6726 (1994).

[0057] PVA-based resin can typically be produced by the partial saponification of a vinyl ester-based polymer obtained by the polymerization of a vinyl ester compound (vinyl acetate-based monomer).

[0058] Examples of vinyl ester compounds include vinyl formate, vinyl acetate, vinyl trifluoroacetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl verstatate Petition 870250073472, dated 08 / 20 / 2025, pp. 42 / 61 13 / 21 vinyl, vinyl palmitate, vinyl stearate and vinyl pivalate. Preferably, vinyl acetate is used. These vinyl ester compounds can be used alone or in combination of two or more.

[0059] PVA-based resin can be a resin based on Unmodified or modified PVA. Modified PVA-based resin can be produced by copolymerizing a vinyl ester compound and an unsaturated monomer other than vinyl ester compounds and saponifying the resulting copolymer. Alternatively, it can be produced by modifying the hydroxyl group of the vinyl alcohol unit and / or the ester group of the vinyl ester unit in an unmodified PVA with cationic, anionic, hydrophobic, or similar groups.

[0060] The PVA-based resin content of the coating agent is 0.1 to 5.0 parts by mass relative to 100 parts by mass of acrylic-based resin and is preferably 0.1 to 3.0 parts by mass, more preferably 0.1 to 2.0 parts by mass.

[0061] The total amount of acrylic-based resin and polyvinyl alcohol-based resin in the resin components of the coating agent is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and even more preferably 95% to 100% by mass, but may be 100% by mass.

[0062] The total amount of acrylic-based resin and polyvinyl alcohol-based resin in the coating agent solids is preferably 80% to 100% by mass, more preferably 85% to 100% by mass, and even more preferably 90% to 100% by mass. When the coating agent contains a surfactant, an initiator, a neutralizer, a preservative, or the like, these are also included in the solids.

[0063] The solids content of the coating agent is preferably Petition 870250073472, dated 08 / 20 / 2025, pp. 43 / 61 14 / 21 cia from 0.5% to 55% by mass, more preferably from 1.0% to 50% by mass and even more preferably from 1.5% to 45% by mass. When the coating agent contains a surfactant, an initiator, a neutralizer, a preservative or the like, these are also included in the solids. Production Method for Coating Agent for Outdoor Pile

[0064] The coating agent for an outdoor pile according to the present invention can be produced by adding PVA-based resin to acrylic-based resin. Alternatively, the coating agent for an outdoor pile according to the present invention can be produced by polymerizing acrylic-based resin from acrylic-based resin raw materials and adding PVA-based resin at least once before, during, and after polymerization. Method for Preventing Dust Generation and / or Increased Humidity in Outdoor Piles

[0065] The method according to the present invention for preventing dust generation and / or increased humidity in an outdoor pile comprises spraying an O / W emulsion containing acrylic-based resin and polyvinyl alcohol-based resin onto an outdoor pile.

[0066] Preferably, the acrylic-based resin is a styrene acrylic resin and / or a vinyl acetate acrylic resin. Outdoor Battery

[0067] In the present invention, the outdoor pile to be treated refers to a material such as coal, ore, coke, slag, dust, wood shavings, paper slurry or similar piled up in an outdoor storage yard. Spraying Method Petition 870250073472, dated 08 / 20 / 2025, pp. 44 / 61 15 / 21

[0068] The method for spraying the coating agent onto an outdoor pile can be carried out, but is not particularly limited to, spraying from a water truck onto the pile, spraying from an external forklift, or selecting an appropriate pump or nozzle according to the individual case.

[0069] The spray quantity is determined appropriately according to the coating agent used and the degree of prevention of dust or moisture buildup required with respect to the outdoor pile. Preferably, the diluted coating agent is sprayed onto the outdoor pile in a quantity per surface area of ​​about 1 L / m2 to 3 L / m2.

[0070] After spraying, the coating agent is naturally dried to form a film.

[0071] The coating film thus formed is thick and resistant and therefore effective in preventing dust. Furthermore, the coating film hardly cracks and therefore does not allow moisture to penetrate easily, thus being highly effective in preventing moisture buildup. As a result, the coating film is also effective in preventing coal leaks. Examples

[0072] Although the present invention is described in more detail based on the Examples, the present invention is not limited to the following Examples. Raw Materials

[0073] The following raw materials were used: Styrene-based monomer • ST: Styrene Vinyl acetate-based monomer • VA: Vinyl acetate Petition 870250073472, dated 08 / 20 / 2025, pp. 45 / 61 16 / 21 Acrylic monomer • 2EHA: 2-Ethylhexyl acrylate • MMA: Methyl methacrylate • BA: Butyl acrylate • AAC: Acrylic acid PVA • PVA 1 (viscosity-average degree of polymerization: 2400, degree of saponification: 88) • PVA 2 (viscosity-average degree of polymerization: 1500, degree of saponification: 88) • PVA 3 (viscosity-average degree of polymerization: 500, degree of saponification: 88) • PVA 4 (viscosity-average degree of polymerization: 3300, degree of saponification: 88) Evaluation (1) Film Strength and Film Thickness

[0074] Coating agents from Examples and Examples Comparisons were evaluated as described below.

[0075] A container 30 cm long, 15 cm wide, and 10 cm high was loaded with coal with a particle size of 5 mm or less and, in this state, was subjected to a natural drop of 10 times from a height of about 1 cm to adjust the height of the coal load layer to 5 cm and flatten the top surface of the load layer. The coating agent (O / W emulsion) was sprayed onto the top surface of the resulting coal layer at a rate of 2 L / m² per top surface area using a sprayer. The coal layer was then allowed to dry naturally, and the strength and thickness of the resulting coating film were measured.

[0076] The film's resistance was measured at five points for Petition 870250073472, dated 08 / 20 / 2025, pp. 46 / 61 17 / 21 each sample with a Yamanaka hardness test, and the measurements were averaged.

[0077] The film thickness was measured at five points for each sample with a caliper, and the measurements were averaged. Coating Agent Production: Method 1

[0078] A pre-emulsion (60% solids content by mass) containing either styrene-based monomer or vinyl acetate-based monomer, an acrylic monomer, PVA, a surfactant (LATEMUL E-1000A / Kao / 30% by mass of the product) and an initiator (ammonium persulfate) was dropped into a nitrogen atmosphere at a reaction temperature of 85°C for 2 hours and then matured at 85°C for 3 hours to produce a reaction liquid. A neutralizer was added to the resulting reaction liquid to obtain a coating agent.

[0079] The mixed proportions of styrene-based monomer, vinyl acetate-based monomer, acrylic monomer and PVA are presented in Table 1.

[0080] The resulting coating agent was evaluated in terms of film thickness and strength according to the evaluation methods described above. The results are presented in Table 1. Coating Agent Production: Method 2

[0081] A coating agent (O / W emulsion) was produced in the same manner as in method 1 above, except that a neutralizer and PVA were added to the reaction liquid together, instead of adding PVA to the pre-emulsion.

[0082] The mixed proportions of styrene-based monomer, vinyl acetate-based monomer, acrylic monomers and PVA are presented in Table 1.

[0083] The resulting coating agent was evaluated in terms Petition 870250073472, dated 08 / 20 / 2025, pp. 47 / 61 18 / 21 film thickness and strength according to the evaluation methods described above. The results are presented in Table 1. Coating Agent Production: Method 3

[0084] A coating agent was produced in the same manner as in method 1 above, except that PVA was added to the preemulsion and also to the reaction liquid along with the neutralizer. The mixed proportions of the styrene-based monomer, vinyl acetate-based monomer, acrylic monomers and PVA are presented in Table 1.

[0085] The resulting coating agent was evaluated in terms of film thickness and strength according to the evaluation methods described above. The results are presented in Table 1. Petition 870250073472, dated 08 / 20 / 2025, pp. 48 / 61 Table 1 Raw material (part(s) by mass) Production method for the coating agent Evaluation ST VA 2EHA MMA BA AAC PVA1 (2400) PVA2 (1500) PVA3 (500) PVA4 (3300) Film thickness (mm) Film strength (mm) Example 1 42 51 5 2 0.2 1 9.6 11.2 Example 2 42 51 5 2 0.2 1 11.4 15.4 Example 3 42 51 5 2 0.1 0.3 1 10.4 10.6 Example 4 15 13 70 2 0.2 0.6 1 10.5 15.8 Example 5 15 13 70 2 0.5 0.5 0.5 2 6.9 Example 6: 45 3 50 2 0.5 0.5 2 7.5 15.4 Example 7: 42 51 5 2 1.0 2 13.0 11.4 Example 8: 42 51 5 2 1.0 2 12.8 11.8 Example 9: 42 51 5 2 1.0 2 12.2 12.6 Example 10: 42 51 5 2 1.0 2 11.8 11.2 19 / 21 Petition 870250073472, dated 08 / 20 / 2025, pp. 49 / 61 Raw material (part(s) by mass) Production method for the coating agent Evaluation ST VA 2EHA MMA BA AAC PVA1 (2400) PVA2 (1500) PVA3 (500) PVA4 (3300) Film thickness (mm) Film strength (mm) Example 11 33 50 5 10 2 0.3 0.1 0.1 1.5 3 8.8 18.8 Example 12 80 20 1.6 1 9.6 13.2 Example 13 20 42 38 1 0.5 1 9.5 8.3 Example 14 15 40 45 2 1 9.5 9.7 Example 15 80 20 1.6 1 10.8 10.8 Example 16 60 17 23 0.1 0.1 1 9.5 11.0 Comparative example 1 42 51 5 2 - 9.6 6.4 Comparative example 2 40 60 - 10.2 4.0 20 / 21 Petition 870250073472, dated 08 / 20 / 2025, pages 50 / 61 21 / 21

[0086] Table 1 shows that the coating agents of Examples containing PVA-based resin provide greater film strength than those of the Comparative Examples, which do not contain PVA-based resin. Petition 870250073472, dated 08 / 20 / 2025, pages 51 / 61

Claims

1 / 1 CLAIMS 1. A method for preventing the generation of dust and / or increased humidity in an outdoor pile, characterized in that it comprises spraying an O / W emulsion comprising acrylic-based resin and polyvinyl alcohol-based resin onto the outdoor pile, wherein the polyvinyl alcohol-based resin content of the O / W emulsion is from 0.1 to 5.0 parts by mass relative to 100 parts by mass of acrylic-based resin.

2. Method for preventing dust generation and / or increased humidity in an outdoor pile according to claim 1, characterized in that the acrylic-based resin is a styrene acrylic resin and / or a vinyl acetate acrylic resin. Petition 870250073472, dated 20 / 08 / 2025, pp. 53 / 61