Core-shell particle comprising core aggregate-type core in which fluorine-based resin particles are aggregated and shell layer formed of acrylic resin particles, and method for producing same

Abstract

The present disclosure relates to a new type of core-shell particle in which are formed an aggregate-type core formed by aggregating fluorine-based resin particles and a shell layer formed by closely aggregating acrylic resin particles, and a method for producing same, wherein, surprisingly, the core-shell particle not only has remarkably good flowability and excellent storage stability, but also has better binder properties than single polytetrafluoroethylene particles.

Description

Core-shell particle comprising a core aggregate-type core formed by agglomerating fluorine-based resin particles and a shell layer formed by acrylic-based resin particles, and a method for producing the same

[0001] The present disclosure relates to a core-shell particle in the form of an aggregate having excellent flowability, excellent storability (storability), and excellent fiberization, comprising an aggregate-type core in the form of an aggregate of fluorine-based resin particles and a shell layer formed of acrylic resin particles on the surface of the aggregate-type core.

[0002] Fluorine resins can be used for various purposes such as adhesives, process improvers, and fluidizing agents due to their electrical properties, thermal properties, and bonding properties, and can be used as various materials such as binders for electrodes, anti-dripping agents, powder coatings, fiber covering materials, and automobile parts.

[0003] However, the above fluorinated resin has a problem of poor flowability during processes such as transportation, storage, processing, or stirring. The problem of poor flowability of the above fluorinated resin generally occurs when the fluorinated resin in the form of resin (particles or powder) coagulates with each other in advance during processes such as transportation, processing, storage, or stirring.

[0004] In order to solve the problem of low flowability of the above fluorinated resin and to achieve higher performance, research is being conducted on modifying the surface of the fluorinated resin or forming a shell layer on the surface of the fluorinated resin with a resin having different surface characteristics.

[0005] However, the following patent document 1 (Japanese Patent Application Laid-Open No. JP2019-112620 A) discloses a core-shell particle having a core containing a perfluoropolymer and a shell layer containing a non-fluorinated resin, but still has technical limitations in that the excellent binder properties of the fluorinated resin are insufficient and excellent flowability is also lacking.

[0006] In addition, core-shell particles formed with a shell layer of non-fluorinated resin on conventional fluorinated particles have the problems described above, and when a high load is applied during storage, they aggregate together to form a cake, so they have a low storage capacity that makes them impossible to use commercially.

[0007] Therefore, there is a need for core-shell particles containing fluorine resins that have remarkably excellent flowability, excellent storability (storage properties), and excellent binder properties.

[0008] One aspect of the present disclosure is to provide a novel core-shell particle in which fluorine-based resin particles are aggregated into a core in the form of an aggregate and acrylic resin particles are aggregated on the surface of the aggregate-like core, thereby solving the problems of low flowability, low binder properties, and low storability of a conventional single fluorine-based resin and a single core-shell particle coated with a shell layer formed by polymerization on the surface of the single fluorine-based resin particle.

[0009] One aspect of the present disclosure provides a method for manufacturing a core-shell particle in which fluorine-based resin particles are aggregated to form a core and acrylic resin particles are aggregated to form a shell layer as an outer layer on the surface of the aggregate-based core.

[0010] One aspect of the present disclosure provides a core-shell particle capable of easily agglomerating fluorine-based resin particles, maintaining the form of an aggregated core formed by the agglomerated fluorine-based particles, and forming a shell layer, and a method for producing the same.

[0011] The present disclosure can provide a core-shell particle having an average particle diameter (D50) of 500 to 3,000 μm, including an aggregate-type core formed by agglomerating fluorine-based resin particles and a shell layer formed by agglomerating acrylic resin particles on the surface of the aggregate-type core.

[0012] As one aspect of the present disclosure, the fluorine-based resin particles may include a fluorine-based polymer polymerized with one or more fluorinated monomers selected from vinylidene difluoride, vinyl fluoride, chlorotrifluoroethylene, tetrafluoroethylene, perfluoroalkyl vinyl ether, and hexafluoropropylene.

[0013] As one embodiment of the present disclosure, the fluorine-based polymer may be polymerized with one or more selected from tetrafluoroethylene, perfluoroalkyl vinyl ether, and hexafluoropropylene.

[0014] The above acrylic resin particles may include one or more selected from a methyl methacrylate homopolymer; and an acrylic copolymer of one or more comonomers selected from methyl methacrylate and ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, I-butyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and styrene monomers.

[0015] As one aspect of the present disclosure, the acrylic resin particles may include an acrylic copolymer.

[0016] As one embodiment of the present disclosure, the acrylic copolymer may have 70 to 99.9 wt% of methyl methacrylate polymerization units based on 100 wt% of the total polymerization units.

[0017] As one aspect of the present disclosure, the aggregate-type core is an aggregate in which fluorine-based resin particles having an average particle diameter (D50) of 0.01 to 100 ㎛ are closely aggregated with each other, and the average particle diameter (D50) of the aggregate-type core may be 200 to 2,500 ㎛.

[0018] As one aspect of the present disclosure, the fluorine-based resin particles may have an average particle diameter (D50) of 0.1 to 50 μm.

[0019] As one aspect of the present disclosure, the thickness of the shell layer may be 50 to 500 μm.

[0020] As one aspect of the present disclosure, the acrylic resin particles may have an average particle diameter (D50) of 0.01 to 100 μm.

[0021] As one aspect of the present disclosure, the acrylic resin particles may have an average particle diameter (D50) of 0.1 to 50 μm.

[0022] As one aspect of the present disclosure, the core-shell particle may include a shell layer in an amount of 1 to 50 wt% based on the total weight.

[0023] As one aspect of the present disclosure, the core-shell particle may be coated with a shell layer at 90% or more of the total surface area of ​​the aggregated core.

[0024] As one aspect of the present disclosure, the core-shell particle may be a core-shell particle having a shell layer that covers 100% of the total surface area of ​​the aggregated core, excluding the voids between the acrylic resin particles.

[0025] As one aspect of the present disclosure, the core-shell particles may include one or more coagulants selected from acetate, sulfate and nitrate.

[0026] As one embodiment of the present disclosure, the core-shell particles may have a shear force (Cohesion Thickness) between a stationary core-shell particle and a flowing core-shell particle of 50 mJ / kg or less, measured 100 times at 0.3 rpm using a dynamic powder flow meter from Mercury.

[0027] In one embodiment of the present disclosure, the core-shell particles may have a break energy for forming an avalanche of 100 mJ / kg or less, measured 100 times at 0.3 rpm using a dynamic powder flow meter from Mercury.

[0028] As one aspect of the present disclosure, the core-shell particles may have a basic flowability energy (BFE) of 1,000 mJ or less and a specific energy (SE) of 10 mJ / kg or less, as measured by a flow rheology meter from Freeman Tech.

[0029] The present disclosure provides a formulation comprising the core-shell particles described above.

[0030] As one aspect of the present disclosure, the combination may include an electrode active material.

[0031] As one aspect of the present disclosure, the blend may contain core-shell particles in an amount of 0.1 to 20 wt% based on the total weight.

[0032] In one embodiment of the present disclosure, the combination may be filtered at 95 wt% or more through a 6.3 mm mesh.

[0033] The present disclosure provides a method for manufacturing a core-shell particle, comprising the steps of: introducing a first dispersion solution in which fluorine-based resin particles are dispersed into an aqueous solution containing an organic solvent and a coagulant, thereby forming an aggregate-type core in which the fluorine-based resin particles are aggregated; and introducing a second dispersion solution in which acrylic resin particles are dispersed into the aqueous solution in which the aggregate-type core is formed, thereby forming a shell layer by agglomerating the acrylic resin particles on the surface of the core coagulant, wherein the aggregate-type core has an average particle diameter (D50) of 200 to 2,500 μm.

[0034] In one embodiment of the present disclosure, the organic solvent may be a C1-C7 aliphatic alcohol, a C1-C4 alkyl acetic acid, or a mixed solvent thereof.

[0035] As one embodiment of the present disclosure, the aqueous solution may be a mixture of deionized water and an organic solvent at a weight ratio of 1:0.1 to 9.

[0036] As one aspect of the present disclosure, the coagulant may be one or more selected from acetate, sulfate, and nitrate.

[0037] As one embodiment of the present disclosure, the coagulant may be included in an aqueous solution at a concentration of 0.1 to 5 wt%.

[0038] As one embodiment of the present disclosure, the step of forming the aggregate-type core may be to add 10 to 60 parts by weight of the first dispersion solution with respect to 100 parts by weight of the aqueous solution.

[0039] As one aspect of the present disclosure, the step of forming the aggregate-shaped core may have a stirring speed of 100 to 1,000 rpm.

[0040] As one aspect of the present disclosure, the step of forming the aggregate-type core may be to aggregate fluorine-based resin particles at 40 to 90°C.

[0041] As one embodiment of the present disclosure, the first dispersion solution may have a solid content of 30 to 80 wt% based on the total weight.

[0042] As one aspect of the present disclosure, the step of forming the shell layer may be to form the shell layer by agglomerating acrylic resin particles at 50 to 90°C.

[0043] As one embodiment of the present disclosure, the second dispersion solution may have a solid content of 10 to 50 wt% based on the total weight.

[0044] As one aspect of the present disclosure, the method for manufacturing core-shell particles may have a weight ratio of the first dispersion solution and the second dispersion solution being introduced of 1:0.1 to 1.5.

[0045] As one aspect of the present disclosure, the core-shell particles may have a cohesion thickness of 50 mJ / kg or less, 30 mJ / kg or less, preferably 25 mJ / kg or less, and more preferably mJ / kg or less, and a break energy of 100 mJ / kg or less, 70 mJ / kg or less, preferably 65 mJ / kg or less, and more preferably 50 mJ / kg or less, between core-shell particles measured by a measurement method defined in the present disclosure, and thus may have remarkably excellent flowability without being tangled with each other during processes such as transportation, processing, storage, or stirring.

[0046] As one aspect of the present disclosure, the core-shell particles are free from a caking phenomenon in which core-shell particles aggregate with each other in a storage stability evaluation measured by a measurement method defined in the present disclosure, and therefore can be used after long-term storage.

[0047] As one aspect of the present invention, the core-shell particles have remarkably excellent binder performance and fiberization performance defined in the present invention, and therefore a mixture including the core-shell particles can be provided as a binder, and in particular, can be usefully used as an electrode active material binder.

[0048] As one aspect of the present disclosure, the method for manufacturing the core-shell particle includes a step of forming an aggregate-type core formed by agglomerating fluorine-based resin particles with each other and a step of forming an acrylic shell layer including acrylic-based resin particles, so that the core-shell particle can have easy processability, productivity, and economy, and the manufactured core-shell particle can have excellent flowability with little agglomeration, excellent storage stability, and excellent bindability.

[0049] As one aspect of the present disclosure, the core-shell particle manufacturing method comprises a core in the form of fluorine-based resin particles aggregated with each other, and the aggregate-type core forms an aggregate in which fluorine-based resin particles aggregate with each other, and the average particle diameter of the aggregate-type core and the core-shell particle including the aggregate-type core can be easily controlled with a simple process.

[0050] Accordingly, since the core-shell particles have shell particles covering the entire surface of the aggregated core particles with a uniform thickness, they have excellent flowability and storage stability while maintaining excellent binder properties of the fluorine-based resin particles, so that the fluorine-based resin can control the time of fiberization according to the user's intention.

[0051] Therefore, the core-shell particles can be usefully used as an anti-dripping agent, powder coating, fiber covering material, automobile parts, or a binder for electrodes.

[0052] Figure 1 illustrates the aggregated core-shell particles of Example 1.

[0053] Figure 2 shows a single core-shell particle of Comparative Example 1.

[0054] Figure 3 is an image of the aggregate-shaped core of Example 1 taken with an optical microscope.

[0055] Figure 4 shows an image of the aggregate-shaped core of Example 1 taken using a scanning electron microscope.

[0056] Figure 5 is an image of the core-shell particles of Example 1 taken using a scanning electron microscope (SEM).

[0057] Figure 6 is a scanning electron microscope photograph of a core-shell particle after cutting the core-shell particle to confirm the formation of the core agglomerate and shell layer of the core-shell particle of Example 1.

[0058] Figure 7 is a photograph taken using energy dispersive X-ray spectrometry (SEM-EDX) of the core-shell particles of Example 1 before and after cutting.

[0059] Figure 8 is a photograph of particles remaining on the sieve after the storage stability evaluation of (a) the aggregated core-shell particles of Example 1, (b) the single core-shell particles of Comparative Example 1, and (c) the single PTFE particles of Comparative Example 2.

[0060] Figure 9 is a sieving photograph of a dough containing aggregated core-shell particles of Example 1 taken with a scanning electron microscope (SEM).

[0061] Figure 10 is a sieving photograph of a dough containing single core-shell particles of Comparative Example 1 taken with a scanning electron microscope (SEM).

[0062] Hereinafter, the core-shell particles and their manufacturing methods will be described. Unless otherwise defined, the technical and scientific terms used herein have the meanings commonly understood by those of ordinary skill in the art to which this invention pertains. In the following description, descriptions of known functions and configurations that may unnecessarily obscure the gist of the present disclosure will be omitted.

[0063] Additionally, the singular forms used in this disclosure may be intended to include the plural forms as well, unless the context specifically indicates otherwise.

[0064] In addition, units used in this disclosure without special mention are based on weight, for example, the unit of % or ratio is weight%, and temperature means ℃ unless otherwise defined.

[0065] Additionally, the numerical ranges used in this disclosure include all possible combinations of lower and upper limits and all values ​​within that range, increments logically derived from the shape and width of the defined range, all values ​​that are double-defined, and upper and lower limits of numerical ranges defined in different shapes.

[0066] Unless otherwise specifically defined in the specification of this disclosure, values ​​outside the numerical range that may arise due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0067] The term "includes" in this disclosure is an open-ended description having an equivalent meaning to expressions such as "comprises," "contains," "has," or "characterizes," and does not exclude additional elements, materials, or processes not listed.

[0068] The term '(meth)acrylate' in the present disclosure may be a term meaning 'acrylate' or 'methacrylate'.

[0069] Hereinafter, core-shell particles according to the present disclosure will be described.

[0070] As one aspect of the present disclosure, the core-shell particle may include an aggregate-type core formed by agglomeration of fluorine-based resin particles and a shell layer formed by agglomeration of acrylic resin particles on the surface of the aggregate-type core.

[0071] Core-shell particles having the above structure surprisingly have significantly better flowability and binder properties compared to conventional fluorine resins (powder or particles) and conventional fluorine resin particles coated with a resin other than the fluorine resin.

[0072] As one embodiment of the present disclosure, the core-shell particle may include, as illustrated in the drawing of FIG. 1 below, a core-shell particle (100) that includes an aggregate-type core (10) formed by agglomerating fluorine-based resin particles (11) with each other, and a shell layer (20) formed by closely agglomerating acrylic resin particles (21) with each other on the surface of the aggregate-type core (10).

[0073] Core-shell particles having the above structure surprisingly have significantly better flowability and binder properties than conventional fluorine-based resins (powder or particles) and conventional fluorine-based resin particles coated with other resins.

[0074] As one embodiment of the present disclosure, the core-shell particle may include, as illustrated in the drawing of FIG. 1 below, a core-shell particle (100) that includes an aggregate-type core (10) formed by agglomerating fluorine-based resin particles (11) with each other, and a shell layer (20) formed by closely agglomerating acrylic resin particles (21) with each other on the surface of the aggregate-type core (10).

[0075] In one embodiment, the conventional single core-shell particle (200) described above may be in the form of a polymerized shell layer (40) formed by polymerizing a monomer on the surface of a single fluorine-based resin particle (30), as illustrated in the drawing of FIG. 2 below.

[0076] The core-shell particle (100) described above has remarkable flowability and excellent storability compared to a single core-shell particle (200) in which a single fluorine-based resin particle (30) polymerized shell layer (40) is formed, and at the same time has excellent binder properties, so the core-shell particle (100) can have excellent handleability in a process and can be preferred.

[0077] As one aspect of the present disclosure, the fluorine-based resin particles may be in a particle state including a fluorine-based resin, and the fluorine-based resin may be a fluorine-based polymer that is polymerized by including one or more fluorine-based monomers selected from, but not limited to, vinylidene difluoride, vinyl fluoride, chlorotrifluoroethylene, tetrafluoroethylene, perfluoroalkyl vinyl ether, and hexafluoropropylene, as long as it is capable of being fiberized.

[0078] In another aspect of the present disclosure, the fluorinated monomer may be one or more perfluoro monomers selected from tetrafluoroethylene, perfluoroalkyl vinyl ether, and hexafluoropropylene.

[0079] The above fluoropolymer can have high heat resistance, excellent fiberization properties, and excellent binder properties, and thus can be usefully used as an anti-dripping agent, powder coating, fiber coating material, automobile parts, or electrode binder. The fluoropolymer polymerized by including the above perfluoro monomer has even better heat resistance, even better binder properties, and excellent fiberization properties, and thus can be particularly usefully used as an electrode binder, but this is not necessarily limited thereto.

[0080] As one embodiment of the present disclosure, the fluorine-based polymer is not particularly limited as long as it does not impair the physical properties of the core-shell particles produced, but as a non-limiting example, it may be polymerized by further including an α-olefin-based monomer that does not contain one or more fluorine substituents selected from ethylene, propylene, n-butylene, and methyl methacrylate.

[0081] In terms of implementing better binder properties of the manufactured core-shell particles, it may be preferred to use a single polymer of the fluorinated monomer described above, but it may also include the α-olefin monomer described above.

[0082] For example, when the fluorine-based polymer is a copolymer further including an α-olefin monomer, the fluorine-based monomer polymerization unit may be 70 wt% or more based on 100 wt% of the total polymerization units, and in another embodiment, it may be 80 wt% or more, or 90 wt% or more, and although the upper limit is not limited, it may be less than 100 wt%, or 99 wt% or less. Core-shell particles manufactured including a fluorine-based resin satisfying the polymerization unit in the above range may have even more significantly excellent heat resistance and binder properties, and thus may be preferred. More preferably, the fluorine-based polymer may be polytetrafluoroethylene, and since the polytetrafluoroethylene satisfies the polymerization unit in the above range and is polymerized including a perfluoroelastomer, it may be the best embodiment, but is not necessarily limited thereto.

[0083] As one aspect of the present disclosure, the fluorine-based resin particles may include one or more selected from a plasticizer, an emulsifier, a heat stabilizer, and an activator, as long as the properties of the core-shell particles produced are not impaired.

[0084] The above fluorine-based particles can further include the above additives depending on the material, such as an anti-dripping agent, powder coating, fiber covering material, automobile parts, or electrode binder, to provide optimal properties for each material.

[0085] In one embodiment of the present disclosure, the fluorine-based resin particles may have an average particle diameter (D50) of 0.01 µm or more, or 0.05 µm or more, 0.10 µm or more, 0.15 µm or more, 0.20 µm or more, 90.00 µm or less, 80.00 µm or less, 70.00 µm or less, 60.00 µm or less, 50.00 µm or less, 40.00 µm or less, 30.00 µm or less, 20.00 µm or less, 15.00 µm or less, 10.00 µm or less, 8.00 µm or less, 7.00 µm or less, 6.00 µm or less, or 5.00 µm or less. For example, it may be 0.01 to 100.00 μm, 0.01 to 50.00 μm, 0.01 to 30.00 μm, 0.01 to 20.00 μm, 0.01 to 10.00 μm, 0.01 to 5 μm, 0.05 to 5 μm, or 0.1 to 5 μm.

[0086] Fluorine-based resin particles having an average particle diameter satisfying the above range can be aggregated to form an aggregate-type core well, so that core-shell particles manufactured including them can have significantly excellent flowability and excellent storage stability, and can have excellent binder properties, and thus may be preferred. However, this is not necessarily limited as long as the fluorine-based resin particles can be aggregated to form an aggregate-type core and do not impair the physical properties of the core-shell particles including them.

[0087] In another aspect of the present disclosure, the fluorine-based resin particles may preferably have an average particle diameter (D50) of 0.1 to 1 μm, or 0.1 to 0.5 μm, in terms of the core-shell particles manufactured including the fluorine-based resin particles having better flowability, better handleability, and better binder properties, but this is not necessarily limited thereto.

[0088] As one aspect of the present disclosure, the aggregate-type core is an aggregate in which fluorine-based resin particles having an average particle diameter in the above range are closely aggregated with each other, and the average particle diameter (D50) of the aggregate-type core may be 200 to 2,000 μm.

[0089] In another embodiment of the present disclosure, the aggregate-type core may have an average particle diameter (D50) of 200 μm or more, 300 μm or more, 400 μm or more, 500 μm or more, 600 μm or more, 700 μm or more, 1,800 μm or less, 1,500 μm or less, 1,300 μm or less, 12,00 μm or less, or 1,000 μm or less. For example, the average particle diameter may be 200 to 1,800 μm, 200 to 1,500 μm, 200 to 1,000 μm, 500 to 1,000 μm, or 700 to 1,000 μm.

[0090] The aggregated core having the average particle size in the above range has a shell layer coated on the surface of 90% or more of the entire surface area, and the core-shell particles manufactured including this not only have remarkably excellent flowability and excellent storability, but also have excellent binder properties, so that they can be usefully used as an electrode binder, powder coating, etc. Preferably, the shell layer is formed by coating the entire surface of the aggregated core.

[0091] The core-shell particles above can have remarkably excellent flowability and excellent binder properties at the same time, as the shell layer is formed by the aggregation of acrylic resin particles, which have properties completely different from those of fluorine resin particles.

[0092] In one embodiment of the present disclosure, the acrylic resin particles may include one or more selected from a methyl methacrylate homopolymer and an acrylic copolymer copolymerized with one or more comonomers selected from methyl methacrylate and ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, I-butyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and α-styrene.

[0093] In another aspect of the present disclosure, the acrylic resin particles may include an acrylic copolymer.

[0094] The above acrylic resin particles are not particularly limited as long as they do not impair the properties of the shell layer and core-shell particles formed by them, but an acrylic copolymer polymerized with methyl methacrylate and the above comonomer can better form the shell layer, and the core-shell particles produced can have remarkably excellent flowability and excellent storability (storability), so they may be preferred.

[0095] As one embodiment of the present disclosure, the acrylic copolymer included in the acrylic resin particles may be a copolymerization of methyl methacrylate and a comonomer selected from among n-butyl (meth)acrylate, t-butyl (meth)acrylate, and iso-butyl (meth)acrylate.

[0096] In another embodiment, the acrylic copolymer may be preferably, but is not necessarily limited to, a methyl methacrylate-n-butylacrylate copolymer.

[0097] In one embodiment of the present disclosure, the acrylic copolymer may contain 70 to 99.9% of methyl methacrylate polymerization units, or in another embodiment, 80 to 99.9%, 80 to 95%, 80 to 90%, or 80 to 85% by weight, based on 100% by weight of total polymerization units.

[0098] An acrylic copolymer satisfying the polymerization unit in the above range may be preferably used as a shell layer of the core-shell particle, since the core-shell particle manufactured by including the acrylic copolymer may have excellent storage properties and flowability.

[0099] As one aspect of the present disclosure, the acrylic resin particles may include one or more additives selected from a plasticizer, an emulsifier, a heat stabilizer, and a lubricant, as long as the additives do not impair the physical properties of the core-shell particles being manufactured.

[0100] The above acrylic resin particles can further include the above additives depending on the material in which the manufactured core-shell particles are used, such as anti-dripping agents, powder coatings, fiber covering materials, automobile parts, or electrode binders, to provide optimal properties for each material.

[0101] In one embodiment of the present disclosure, the acrylic resin particles may have an average particle diameter (D50) of 0.01 µm or more, 0.05 µm or more, 0.10 µm or more, 100.00 µm or less, 80.00 µm or less, 70.00 µm or less, 60.00 µm or less, 50.00 µm or less, 30.00 µm or less, 20.00 µm or less, 10.00 µm or less, 7.00 µm or less, or 5.0 µm or less. For example, it may be 0.01 to 100.00 μm, 0.05 to 100.00 μm, 0.1 to 100.00 μm, 0.1 to 50 μm, 0.1 to 20 μm, 0.1 to 10.00 μm or 0.1 to 5.00 μm or less.

[0102] Acrylic resin particles having an average particle size in the above range may be preferred because they aggregate with each other on the surface of the aggregate-type core to form a better shell layer, so that the manufactured core-shell particles can have more remarkable flowability.

[0103] In another aspect of the present disclosure, the acrylic resin particles may have an average particle diameter of 0.1 to 1 μm, or 0.5 to 1 μm, in terms of better forming a shell layer on the surface of the core aggregate, but this is not necessarily limited thereto.

[0104] As one aspect of the present disclosure, the core-shell particles may include one or more coagulants selected from acetate, sulfate, and nitrate.

[0105] The coagulant of the core-shell particles can form an aggregate-type core by coagulating fluorine-based resin particles in the manufacturing method described below, and can form a shell layer by coagulating acrylic resin particles on the surface of the formed aggregate-type core.

[0106] In addition, the core-shell particles may be preferred because they contain a residual coagulant from the manufacturing method described below, allowing the fluorine-based resin particles and acrylic-based resin particles to maintain an aggregated form, but this is not necessarily limited.

[0107] The above coagulant is described in more detail in the method for manufacturing core-shell particles described later, so a detailed description thereof will be omitted.

[0108] In one aspect of the present disclosure, the shell layer of the core-shell particle may have a thickness of 50 to 500 μm, 300 μm or less, 200 μm or less, 150 μm or less, or 100 μm or less, and as an example, may be 50 to 200 μm, 50 to 150 μm, or 50 to 100 μm, or values ​​in the middle ranges of the upper and lower limits.

[0109] Core-shell particles formed with a shell layer satisfying the thickness of the above range surprisingly maintain the excellent binder properties of fluorine-based resin particles and can have very remarkable flowability and excellent storability, and thus may be preferred; however, this is not necessarily limited as long as it satisfies the properties targeted in the present invention.

[0110] The shell layer thickness of the core-shell particles was measured using the measuring method defined in the present invention, and specifically, the core-shell particles were measured at five locations at 50x magnification using a scanning electron microscope (SEM), and the average value was calculated to obtain the result.

[0111] In one embodiment of the present invention, the core-shell particles have an average particle diameter (D50) of 500 ㎛ or more, 520 ㎛ or more, 600 ㎛ or more, 620 ㎛ or more, 700 ㎛ or more, 830 ㎛ or more, 900 ㎛ or more, 930 ㎛ or more, 950 ㎛ or more, 960 ㎛ or more, 974 ㎛ or more, 984 ㎛ or more, 1,000 ㎛ or more, 1,020 ㎛ or more, 1,040 ㎛ or more, 1,051 ㎛ or more, 1,100 ㎛ or more, 1,103 ㎛ or more, 1,166 ㎛ or more, 3,000 ㎛ or less, 2,500 ㎛ or less, 2,000 ㎛ or less, 1,800 ㎛ or less, 1,750 ㎛ or less. It may be 1,600 ㎛ or less, 1,500 ㎛ or less. For example, it may be 500 to 3,000 ㎛, 500 to 2,000 ㎛, 500 to 1,500 ㎛, or 1,000 to 1,500 ㎛, which can be controlled by the average particle size of the aggregate-type core and the thickness of the shell layer, and in the manufacturing method described below, it can be easily controlled by the stirring speed.

[0112] Core-shell particles satisfying the average particle diameter of the above range can be included with high dispersibility in powder coatings or electrode binders, etc. containing the core-shell particles, and can have excellent flowability and excellent binder properties as described above, and thus may be preferred. However, since the core-shell particles can be adjusted by the user depending on the intended use, the above range is not necessarily limited.

[0113] In one embodiment of the present disclosure, the core-shell particles may have an average particle diameter Span value of 1.50 or less, 1.45 or less, 1.43 or less, 1.40 or less, 1.38 or less, 1.35 or less, 1.33 or less, 1.31 or less, 1.30 or less, 1.27 or less, 1.26 or less, 1.25 or less, 1.24 or less, 1.23 or less, 1.20 or less, 1.05 or more, 1.10 or more, or 1.15 or more, when measured using the average particle diameter measuring method described above. For example, it may be 1.05 to 1.50, 1.05 to 1.45, 1.05 to 1.40, 1.05 to 1.38, 1.05 to 1.33, 1.05 to 1.30, 1.05 to 1.27, 1.05 to 1.26, 1.05 to 1.23 or 1.05 to 1.20.

[0114] Even if the core-shell particles have an average particle diameter of 500 μm or more as described above, they can have an average particle diameter distribution with a span value of 1.5 or less. Accordingly, the core-shell particles can have a very uniform average particle diameter, and thus can be usefully used as materials for binders, powder coatings, fiber coatings, or automobile parts.

[0115] As one aspect of the present invention, the core-shell particle may contain a shell layer in an amount of 1 to 50 wt%, preferably 1 to 30 wt%, and more preferably 10 to 30 wt%, based on the total mass, and thus may have both excellent flowability and binder properties, which may be preferred.

[0116] Core-shell particles including a shell layer with a content within the above range simultaneously satisfy both remarkably excellent flowability and excellent binder properties, and can be particularly useful as a binder for electrodes. However, this is not necessarily limited as long as it satisfies the properties targeted by the present invention.

[0117] In one aspect of the present disclosure, the core-shell particle may be coated with a shell layer at 90% or more of the total surface area of ​​the aggregated core, preferably 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, or 98% or more.

[0118] The above core-shell particles may be preferred because they have excellent flowability, excellent handleability, and excellent storage stability, as the shell layer is formed excellently on the aggregated core.

[0119] As one aspect of the present disclosure, the core-shell particle may be coated with a shell layer at 100% of the total surface area of ​​the aggregated core, excluding the voids between the acrylic resin particles.

[0120] As shown in the photo taken by energy dispersive X-ray spectrometry (SEM EDX) of Fig. 7 below, the core-shell particles have fluorine-based resin particles forming an aggregate-type core and acrylic-based resin particles forming a shell layer, so that the composition of the aggregate-type core and the shell layer can be clearly defined, and the shell layer is formed 100% on the surface of the aggregate-type core, so that it has remarkably excellent flowability and excellent storage stability, while simultaneously having excellent binder properties.

[0121] Hereinafter, a method for manufacturing the core-shell particles will be described.

[0122] In one aspect of the present disclosure, the core-shell particle may be manufactured by including a step of introducing a first dispersion solution in which fluorine-based resin particles are dispersed into an aqueous solution containing an organic solvent and a coagulant, thereby forming an aggregate-type core in which the fluorine-based resin particles are aggregated, and a step of introducing a second dispersion solution in which acrylic resin particles are dispersed into the aqueous solution in which the aggregate-type core is formed, thereby forming a shell portion by causing the acrylic resin particles to aggregate on the surface of the aggregate-type core.

[0123] The method for manufacturing the above core-shell particles is not a conventional method of coating an acrylic resin on a single fluorine-based resin particle or modifying the surface of a single fluorine-based resin particle. That is, the present disclosure provides a core-shell particle in which fluorine-based resin particles are aggregated and an acrylic resin particle is aggregated to form a shell layer on the surface of the aggregated core.

[0124] The above core-shell particles can have significantly superior flowability and storage stability, and at the same time, superior binder properties, unlike conventional single core-shell particles having only fluorine-based resin particles, and thus can be usefully used as an anti-dripping agent, powder coating, fiber covering material, automobile parts, and electrode binder.

[0125] In addition, the above core-shell particle manufacturing method may have the following unexpected characteristics, as it manufactures an aggregate-type core by agglomerating fluorine-based resin particles, and then forms a shell layer by agglomerating acrylic-based resin particles on the surface of the core aggregate.

[0126] That is, as described above, the core-shell particles have an aggregated core in which fluorine-based resin particles are aggregated and a shell layer coated with acrylic-based resin particles, so that the core-shell particles do not aggregate with each other and have remarkably good flowability, and in addition, when multi-layered packaging is performed, the core-shell structure is sufficiently maintained by the shell layer aggregated on the surface, resulting in excellent storage stability.

[0127] In addition, when the fluorine resin core in the form of the above aggregate and the shell layer of the acrylic particles are formed, individual fluorine single particles (meaning primary particles, non-aggregate particles) or core-shell particles with almost no acrylic single particles are created, and the solid content separation method is simple, so it can have the advantage of a process with high economic efficiency and productivity.

[0128] The step of forming the above-mentioned aggregate-type core may be preferred because it can maintain polarity by including an organic solvent in the aqueous solution, thereby forming a uniform aggregate and preventing the residue of unagglomerated fluorine-based resin particles.

[0129] In addition, the core-shell particles formed in the aqueous solution containing the organic solvent are formed by fluorine-based resin particles coagulating with each other in a substantially aggregate-type core, and a shell layer formed by coagulating only acrylic-based resin particles is formed on the surface of the aggregate-type core, so that a core-shell particle having a clear core portion and shell portion can be manufactured.

[0130] In one embodiment of the present disclosure, the organic solvent may be a C1-C7 aliphatic alcohol, a C1-C4 alkyl acetic acid or a mixed solvent thereof, preferably a C1-C7 aliphatic alcohol, more preferably methanol, ethanol or butanol.

[0131] The aliphatic alcohols described above may have excellent miscibility with water, and may be preferred because they can better maintain the polarity of the aqueous solution in the step where fluorine-based resin particles aggregate to form an aggregate-like core and in the step where acrylic-based resin particles aggregate to form a shell layer, but this is not necessarily a limitation.

[0132] As one embodiment of the present disclosure, in the step of forming the aggregate-type core, the aqueous solution may be a deionized water and an organic solvent in a weight ratio of 1:0.1 to 9, preferably 1:0.3 to 9, more preferably 1:0.3 to 5 or 1:0.3 to 1.

[0133] An aqueous solution in which deionized water and water are mixed in the weight ratio of the above range can be preferred because the aggregate-type core is formed by the agglomeration of fluorine-based resin particles, and the shell layer is formed by the agglomeration of acrylic-based resin particles, so that a core-shell layer with a clear distinction between the aggregate-type core and the shell layer can be formed.

[0134] As one embodiment of the present disclosure, the coagulant may be one or more selected from acetate, sulfate, and nitrate, as described above.

[0135] The above coagulant can be used without limitation as long as it is recognizable by a person skilled in the art, and examples thereof include inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, and nitric acid; organic acids such as acetic acid; halides of alkali metals such as sodium and potassium; alkali metal salts with inorganic acids; and alkali metal salts with organic acids.

[0136] In another embodiment, the coagulant may be calcium acetate hydrate or aluminum nitrate hydrate, but is not necessarily limited thereto, as long as the fluorine-based resin particles and the acrylic-based resin particles can each coagulate with each other to produce core-shell particles.

[0137] As one embodiment of the present invention, the coagulant may be included in the aqueous solution at a concentration of 0.1 to 5 wt%, preferably 0.1 to 3 wt%, and more preferably 0.1 to 1 wt%.

[0138] Core-shell particles manufactured in an aqueous solution containing a coagulant at a concentration in the above range may be preferred because the acrylic resin particles can form a well-coagulated shell layer on the surface of the aggregated core, and can prevent deterioration of the physical properties of the core-shell particles due to excessive coagulant. However, if it is possible to manufacture aggregated core-shell particles, they can be used without limitation.

[0139] Of course, the above-mentioned coagulant also plays a role in coagulating the fluorine-based resin particles and the acrylic-based resin particles well with each other in the formation of the aggregated core and shell layer of the core-shell particle, but as described above, it may be preferred because it can remain in the core-shell particle being manufactured and maintain the form of the aggregated core in which the fluorine-based resin particles are aggregated and the shell layer formed by coagulating the acrylic-based resin particles on the surface of the aggregated core, but this is not necessarily limited.

[0140] As one embodiment of the present disclosure, the fluorine-based resin particles dispersed and included in the first dispersion solution in the step of forming the aggregate-type core have the same monomer composition and average particle diameter (D50) as the fluorine-based resin particles described above, and therefore, a detailed description thereof will be omitted.

[0141] In one embodiment of the present disclosure, the first dispersion solution may have a solid content of 30 to 80 wt% based on the total weight, and in another embodiment, may have a solid content of 30 to 70 wt% or 40 to 65 wt%, but is not limited thereto. As described above, the first dispersion solution is a commercialized product, and can be manufactured by utilizing or polymerizing it, so it will not be described further.

[0142] In one embodiment of the present disclosure, the step of forming the aggregate-type core may be to add 10 to 60 parts by weight of the first dispersion solution with respect to 100 parts by weight of the aqueous solution, and in another embodiment, may be to add 10 to 50 parts by weight, 10 to 40 parts by weight, or 10 to 30 parts by weight.

[0143] The step of forming an aggregate-type core by adding the first dispersion solution having the solid content described above into an aqueous solution within the above range can be manufactured with the average particle size of the target aggregate-type core and core-shell particles including the same, and has excellent stirrability and excellent processability in manufacturing, and thus may be preferred.

[0144] As one embodiment of the present disclosure, the first dispersion solution may be a product polymerized by emulsion polymerization or suspension polymerization of a fluorine-based polymer, and may include deionized water as a solvent, and may include an emulsifier, a dispersant, a dispersing agent, a chain transfer agent, and an initiator, etc., as long as they are recognizable by a person skilled in the art, and are not necessarily limited thereto.

[0145] In one aspect of the present disclosure, the step of forming the aggregate-shaped core may have a stirring speed of 100 to 1,000 rpm, preferably 800 rpm or less, 700 rpm or less, more preferably 500 rpm or less, or 200 rpm or more, and may satisfy numerical ranges of the upper and lower limits of the above range.

[0146] In the step of forming the above-mentioned aggregate-type core, the stirring speed can control the average particle diameter of the aggregate-type core. That is, the method for producing the core-shell particle can easily control the average particle diameter (D50) of the produced aggregate-type core and the core-shell particle including the same by controlling the stirring speed.

[0147] Therefore, the aggregated core formed at the stirring speed in the range described above and the core-shell particles manufactured including the same may have a target average particle diameter and may be preferred, but this is not necessarily limited to this as it can be adjusted according to the target average particle diameter by a person skilled in the art.

[0148] In one embodiment of the present disclosure, the step of forming the aggregate-type core may be to aggregate fluorine-based resin particles at 40 to 90°C, and in another embodiment, the step may be to aggregate fluorine-based resin particles at 50 to 90°C, 60 to 90°C, 60 to 80°C, or 60 to 70°C.

[0149] When the fluorine-based resin particles are aggregated at a temperature in the above range, an aggregate-type core can be well formed with excellent cohesion, and the fluorine-based resin particles do not fiberize and clump together, so the fluorine-based resin particles targeted in the present disclosure can form an aggregate-type core in a form in which they are aggregated together, which may be preferred, but this does not necessarily limit it unless it impairs the properties of the core-shell particles produced.

[0150] In one embodiment of the present disclosure, the step of forming the aggregate-type core may produce a dispersion solution in which the fluorine-based resin particles are aggregated and the aggregate-type core is dispersed, and the dispersion solution in which the aggregate-type core is dispersed may have a solid content of 5 to 50 wt% with respect to the total mass, and in another embodiment, may have a solid content of 10 to 40 wt% or 10 to 30 wt%.

[0151] In the step of forming the above-mentioned aggregate-type core, after the fluorine-based resin particles are aggregated, the aqueous solution may mean that the aggregate-type core is dispersed at 5 to 50 wt%, which may mean that the introduced fluorine-based resin particles are well aggregated without residue to form the aggregate-type core.

[0152] In addition, an aqueous solution in which aggregate-type cores are dispersed with a solid content in the above range may be preferred because acrylic resin particles can be well aggregated on the surface of the aggregate-type cores to form a shell layer in the step of forming a shell layer described later, but this is not necessarily limited as long as it does not impair the properties of the core-shell particles being manufactured.

[0153] Therefore, the step of forming the aggregate-type core can control the average particle diameter of the aggregate-type core by controlling the stirring speed, the solid content of the first dispersion solution, and the reaction temperature of the agglomeration. As described above, the average particle diameter (D50) can be 200 to 2,500 ㎛, and in another embodiment, it can be 200 to 2,000 ㎛, 200 to 1,800 ㎛, 200 to 1,500 ㎛, 200 to 1,000 ㎛, 500 to 1,000 ㎛, or 700 to 1,000 ㎛.

[0154] The aggregated core having the average particle size in the above range is coated with a shell layer on the surface of 90% or more, preferably 95% or more, and best of all 100% of the entire area, and the core-shell particles manufactured including this not only have remarkably excellent flowability and excellent handleability, but also fiberize well and have excellent binder properties, so that they can be usefully used as a binder for electrodes, powder coatings, etc.

[0155] As one aspect of the present disclosure, the step of forming the shell layer may be to introduce a second dispersion solution in which acrylic resin particles are dispersed into an aqueous solution in which the aggregate-type core described above is formed, so that the acrylic resin particles aggregate on the surface of the core aggregate to form a shell layer.

[0156] The above second dispersion solution may be one in which acrylic resin particles are polymerized using emulsion polymerization or suspension polymerization, and thus may contain water as a solvent, and may further contain acrylic resin particles, an emulsifier, a dispersant, a chain transfer agent, and an initiator.

[0157] The method for preparing the above-mentioned second dispersion solution may be prepared by emulsion polymerization of the manufacturing examples described below, and since this is a known technology, a detailed description thereof is omitted.

[0158] As one embodiment of the present disclosure, the average particle diameter (D50) of the acrylic resin particles dispersed in the second dispersion solution may be 0.01 to 100 μm, as described above, and this may have a manufacturing method effect in addition to the physical property effect of the manufactured core-shell particles described above.

[0159] Acrylic resin particles having an average particle size in the above range may be preferred because they can have a manufacturing method effect in which the acrylic resin particles can be well aggregated to form a shell layer evenly, but this is not necessarily limited as long as a shell layer can be formed on an aggregate-type core.

[0160] As one embodiment of the present disclosure, the acrylic resin particles dispersed in the second dispersion solution have already been described above in terms of the combination of monomers and polymerization units for polymerization, and therefore, a detailed description thereof will be omitted.

[0161] In one embodiment of the present disclosure, the second dispersion solution may have a solid content of 10 to 50 wt%, and in another embodiment, 10 to 40 wt%, 10 to 30 wt%, or 10 to 20 wt%, based on the total weight.

[0162] A second dispersion solution satisfying the solid content within the above range can better form a shell layer on the surface of the aggregate-type core and has less residual acrylic resin particles, so it can have excellent productivity and is therefore preferred.

[0163] As one aspect of the present invention, the weight ratio of the first dispersion solution and the second dispersion solution introduced in the core-shell particle manufacturing method may be 1:0.1 to 1.5, preferably 1:0.4 to 1.5, and more preferably 1:0.5 to 1.2.

[0164] Core-shell particles manufactured by adding the first dispersion solution and the second dispersion solution in the weight ratios of the above ranges may be preferred because they can have both excellent flowability and binder properties by including the shell layer in an amount of 1 to 50 wt%, 1 to 30 wt%, or 10 to 30 wt% with respect to the total mass, as described above.

[0165] Therefore, the core-shell particles can be particularly useful as a binder for electrodes, as they simultaneously satisfy both remarkably excellent flowability and excellent binder properties. However, this is not necessarily limited to the properties targeted by the present invention.

[0166] In one embodiment of the present disclosure, the step of forming the shell layer may be to aggregate acrylic resin particles at 50 to 90°C, and in another embodiment, the step may be to form the shell layer by forming acrylic resin particles at 70 to 85°C.

[0167] The step of forming a shell layer at a temperature in the above range may be preferred because it can maintain the shape of the aggregated core and form the shell layer evenly, and it may not impair the properties of the acrylic resin particles.

[0168] Therefore, the core-shell particle is a two-dimensional core-shell particle that includes an aggregate-type core in which fluorine-based resin particles are aggregated with each other and a shell layer formed by agglomerating acrylic resin particles on the surface of the aggregate-type core, and can simultaneously have significantly better flowability, better storage stability, and better binder properties than conventional fluorine-based single resin particles and core-shell particles coated with acrylic resin.

[0169] In one embodiment of the present disclosure, the core-shell particles have a cohesion thickness of 50.0 mJ / kg or less, 49.1 mJ / kg or less, 40.0 mJ / kg or less, 30.0 mJ / kg or less, 25.0 mJ / kg or less, 24.5 mJ / kg or less, 24.0 mJ / kg or less, 23.0 mJ / kg or less, 22.3 mJ / kg or less, 22.2 mJ / kg or less, 22.0 mJ / kg or less, 21.4 mJ / kg or less, 21.0 mJ / kg or less, 20.9 mJ / kg or less, 20.0 mJ / kg or less, 19.0 mJ / kg or less, 18.5 mJ / kg or less, 18.4 mJ / kg or less, 18.0 mJ / kg or less, 17.6 mJ / kg or less, 17.5 mJ / kg or less, 17.3 mJ / kg or less, 17.0 mJ / kg or less, 16.4 mJ / kg or less, 16.0 mJ / kg or less, and the lower limit is not limited, but may be 5.0 mJ / kg or more or 10.0 mJ / kg or more. For example, the flow shear force of the core-shell particles may be 5 to 50 mJ / kg, 5 to 40 mJ / kg, 5 to 30 mJ / kg, 5 to 20 mJ / kg, or 10 to 20 mJ / kg.

[0170] In addition, as one aspect of the present disclosure, the core-shell particles may have a cohesive break energy measured by the same measuring method as the flow shear force measuring method of 100 mJ / kg or less, 80 mJ / kg or less, 76.8 mJ / kg or less, 70.0 mJ / kg or less, 65.0 mJ / kg or less, 61.5 mJ / kg or less, 60.0 mJ / kg or less, 59.3 mJ / kg or less, 55.2 mJ / kg or less, 52.8 mJ / kg or less, 50.1 mJ / kg or less, 50.0 mJ / kg or less, 49.8 mJ / kg or less, 49.5 mJ / kg or less, and the lower limit is not limited, but may be 20.0 mJ / kg or more, 30.0 mJ / kg or more. For example, the core-shell particles may have a cohesive destruction energy of 20 to 100 mJ / kg, 20 to 80 mJ / kg, 20 to 70.0 mJ / kg, 20 to 65 mJ / kg, 20 to 60 mJ / kg, 20 to 55 mJ / kg, 20 to 51 mJ / kg, 20 to 50 mJ / kg, or 30 to 50 mJ / kg.

[0171] The cohesion thickness of the core-shell particles is the shear force between stationary particles and flowing particles when the drum rotates, and the break energy refers to the energy required for stationary particles to form an avalanche. Therefore, this may refer to the dynamic flowability of the core-shell particles.

[0172] The core-shell particles have very low cohesion between particles in the range of flow shear force (Cohesion Thickness) and cohesive breakdown energy (Break Energy) described above, so that they can have remarkably excellent flowability without being tangled with each other during processes such as transportation, processing, storage, or stirring.

[0173] In one aspect of the present disclosure, the core-shell particle may have a basic flowability energy (BFE) measured by a measurement method defined in the present disclosure of 1,000 mJ or less, 800 mJ or less, 700 mJ or less, 680 mJ or less, 644 mJ or less, 621 mJ or less, 617 mJ or less, 604 mJ or less, 600 mJ or less, 576 mJ or less, 556 mJ or less, 550 mJ or less, 512 mJ or less, 500 mJ or less, or 498 mJ or less, and the lower limit is not limited thereto, but may be 200 mJ or more, 300 mJ or more, or 400 mJ or more. The core-shell particles may have a flow characteristic energy of 200 to 1,000 mJ, 200 to 800 mJ, 200 to 700 mJ, 200 to 600 mJ, 200 to 550 mJ, 300 to 550 mJ, or 300 to 400 mJ.

[0174] In another aspect of the present disclosure, the core-shell particle may have a cohesive energy (Specific Energy, SE) measured by the same measuring method as the Basic Flowability Energy (BFE) described above of 10.0 mJ / g or less, 6.0 mJ / g or less, or 5.0 mJ / g or less, 4.3 mJ / g or less, 4.0 mJ / g or less, 3.9 mJ / g or less, 3.8 mJ / g or less, 3.6 mJ / g or less, 3.5 mJ / g or less, or 3.2 mJ / g or less, and the lower limit is not limited thereto, but may be 1.0 mJ / g or more, 2.0 mJ / g or more, or 3.0 mJ / g or more.

[0175] The core-shell particles can have low static flowability with flow characteristic energy and cohesion energy in the range described above by uniformly covering the surface of the aggregated core with agglomerates of acrylic resin particles, thereby preventing the fluorine resin particles included in the aggregated core from being fiberized in advance, thereby providing excellent flowability and excellent storage stability.

[0176] Therefore, the core-shell particle includes a shell layer formed evenly by agglomeration of acrylic resin particles on the surface of the aggregate-type core, thereby preventing the fluororesin from being fiberized in advance, and thus can have excellent static flowability and dynamic flowability at the same time during the process, and can have excellent storage stability without cake formation when stored for a long period of time.

[0177] That is, as one aspect of the present disclosure, the core-shell particles may have excellent storage stability as measured by the measurement method defined in the present disclosure, which may be due to the absence of agglomeration between core-shell particles when the core-shell particles are left under a certain pressure.

[0178] The excellent storage stability of the core-shell particles is measured by the degree to which the particles coagulate to form a cake when left under a certain pressure, and can have excellent storage stability without coagulation compared to conventional fluorine-based single resin particles and single core-shell particles coated on the surface with acrylic resin.

[0179] Accordingly, the core-shell particles can not only have excellent flowability without prior agglomeration, but can also have excellent stability for a long period of time without agglomeration even when left (loaded) under a constant pressure for a long period of time.

[0180] In one aspect of the present invention, a combination comprising the core-shell particles can be provided.

[0181] The above core-shell particles have excellent flowability due to the absence of prior agglomeration, and when used as a binder, the composition included in the mixture may not be easily separated due to its excellent fiberization properties.

[0182] In one embodiment of the present disclosure, the combination may comprise core-shell particles in an amount of 0.1 to 20 wt%, and in another embodiment, 1 to 10 wt%, based on the total weight, but this is not necessarily limited thereto.

[0183] Since the core-shell particles have excellent binder properties, a dough prepared including the content in the range described above can maintain its shape by excellent binding of the included particles.

[0184] As one aspect of the present disclosure, the combination may include an electrode active material.

[0185] The above core-shell particles can be used as a binder material in various fields such as paints, anti-dripping agents, powder coatings, fiber coating materials, or automobile parts, but in particular, since they bind electrode active materials and maintain the composition excellently, they can be usefully used as a binder for electrode active materials.

[0186] The above electrode active material is not particularly limited as long as it is recognizable by a person skilled in the art, but for example, it may be a positive electrode active material including a lithium composite metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel, or aluminum, which are compounds capable of reversible intercalation and deintercalation of lithium; and a carbon-based negative electrode active material such as crystalline carbon, amorphous carbon, or a carbon composite, which may be used alone or in combination of two or more.

[0187] As one aspect of the present disclosure, the combination may further include a conductive agent.

[0188] The conductive material is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and examples thereof include: graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorinated carbon, aluminum, and nickel powders; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0189] In one embodiment of the present invention, the core-shell particles may be a mixture containing a core-shell particle binder measured by a measuring method defined in the present invention, wherein 90 wt% or more of the mixture is filtered through a 6.30 mm sieve, preferably 95 wt% or more, more preferably 98 wt% or more, and most preferably 100 wt%.

[0190] The above core-shell particles can bind particles included in a mixture with excellent binder properties and fiberization properties, thereby maintaining a shape, and in particular, have even better binder properties for electrode active materials, enabling the production of a mixture that is filtered at 90 wt% or more through a 6.30 mm sieve, so that the mixture described above can be usefully used as a binder for electrode active materials.

[0191] That is, since the core-shell particles have the remarkably excellent flowability and excellent storage stability, they can be usefully used in anti-dripping agents, powder coatings, fiber coating materials, or automobile parts using conventional fluorine-based resins, and in particular, since they have the remarkably excellent flowability and excellent storage stability, and at the same time have binder properties superior to those of pure fluorine-based resins, they can be usefully used as a binder for electrodes.

[0192] The core-shell particles are described in more detail through the following examples. However, the following examples are merely references for describing the present disclosure in detail, and the present disclosure is not limited thereto, and may be implemented in various forms. Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains. Furthermore, the terminology used in the description of the present disclosure is merely for the purpose of effectively describing specific embodiments and is not intended to limit the present disclosure.

[0193] [measurement method]

[0194] 1. Measurement of weight average molecular weight (Mw) [kg / mol]

[0195] To measure the molecular weight of the non-fluorinated resin, 10 mg of the extracted non-fluorinated resin was dissolved in 10 ml of tetrahydrofuran (THF), filtered using a 0.2 μm Teflon filter, and then measured using GPC (Gel Permeation Chromatography) from Waters.

[0196] 2. Measurement of glass transition temperature (Tg) [℃]

[0197] For each fluorine-free resin, the glass transition temperature was calculated using the half Cp method at the inflection point of the second cycle after measuring 2 cycles under the condition of a temperature increase of 10 ℃ per minute using a TA Q20 DSC (differential scanning calorimetry).

[0198] 3. Measurement of the ratio of fluorinated resin and non-fluorinated resin

[0199] The weight loss of 10 mg of dried particles was measured by TGA at a temperature of 10 °C / min up to 600 °C. First, the ratio of fluorinated resin to non-fluorinated resin was measured through the degree of weight loss by utilizing the characteristics of pyrolyzed non-fluorinated resin. In the case of single core-shell particles, 20 g of acetone was added to 10 g of single core-shell particles, shaken, and then dropwise added to 400 g of methanol to obtain precipitated non-fluorinated resin. The precipitated non-fluorinated resin was separated using a vacuum filter, washed three times with methanol, and then vacuum dried in an oven at 25 °C for 24 hours.

[0200] 4. Measurement of average particle diameter and particle size distribution

[0201] The particles were measured using a laser diffraction particle size distribution measuring device (Malvern, MASTERSIZER 3000 hydro) based on a wet measurement method. The average particle size was the D50 value, which is the average particle size measured on a volume basis (when Dn means the diameter of the particle corresponding to n% in terms of integration fraction, “D50” corresponds to 50% in terms of integration fraction on a volume basis). In the above average particle size measurement, the particle size distribution was calculated using the Span value, which is a value calculated by the method of (D90-D10) / D50 in the particle size distribution measuring device. In addition, it was confirmed that the average particle size (D50) of the acrylic resin particles measured above was similar to the image (Fig. 5) taken with a scanning electron microscope (SEM) of the core-shell particles.

[0202] 5. Structural analysis of core-shell particles

[0203] For structural analysis of the particles, core-shell particles were photographed using a scanning electron microscope, and also, for clear distinction of the aggregated core and shell layers, core-shell particles divided into two parts were photographed using a scanning electron microscope. The photographed core-shell particles and the photographed co-shell particles divided into two parts are shown in Fig. 6. The above image measurement method was applied to 10 particles to measure the shell layer thickness, and the average was obtained and cross-validated using the core-shell particles and particle size.

[0204] In order to measure the size of the aggregated core-shell particles and the surface distribution of the shells manufactured in the examples and comparative examples, images of each particle were taken 10 times using a scanning electron microscope (SEM) below, and the average diameter observed with the naked eye was measured, and it was confirmed to be similar to the average particle diameter (D50) measured above. The surface coverage level of the core-shell was observed with the naked eye, and the surface coverage level was classified as follows.

[0205] ○: Covers more than 90% of the core surface visually.

[0206] △: Covers 90 to 30% of the core surface visually.

[0207] X: Covers less than 30% of the core surface visually.

[0208] In addition, in order to confirm whether the aggregated core and shell layers of the core-shell particles manufactured in Example 1 above were clearly formed, energy dispersive X-ray spectrometry (SEM-EDX) was used to photograph the core-shell particles and the core-shell particles divided into two parts, and the results are shown in Fig. 7 below.

[0209] 6. Storage stability analysis

[0210] Each 10 g of particles was placed in a stainless steel container, pressurized with an 11.3 kg weight, and left at 20°C for 4 hours. The particles left in the stainless steel container were then extracted to produce particle blocks. Thereafter, the particles were placed on a 2 mm mesh screen, and the particles were then placed on a 0.6 mm mesh screen and a 0.2 mm mesh screen. The blocks of particles placed on the mesh screen were then crushed for 1 minute with a vibrating sieve (Haver & Boecher, EML 200 Premium), and the weight of the crushed particle blocks was measured and calculated using the following Equation 1. The particles remaining after sieving were photographed and shown in Figure 8.

[0211] [Formula 1]

[0212] Storage stability (%) = [mass of crushed particles (g) / mass of initial particles (g)] X 100

[0213] 7. Measurement of total energy and cohesive energy of particle flow

[0214] The flowability and cohesive energy of the particles were measured using a rheological property measuring device (FT4, Freeman Technology). Specifically, the flowability and cohesive energy of the particles were measured by filling a 50 mm diameter cylinder with particles, and then rotating the impeller at a tip speed of 100 mm / s (8 times), 70 mm / s (1 time), 40 mm / s (1 time), or 10 mm / s (1 time), repeatedly raising and lowering the particles inside the cylinder. At this time, the basic flowability energy (BFE) was measured when the particles inside the cylinder were lowering, and the cohesive energy (specific energy (SE)) was measured when the particles were rising. The BFE and SE of the particles inside the cylinder were measured a total of 11 times when they were raised and lowered, and the average value was obtained.

[0215] 8. Measurement of particle flow shear force and cohesion

[0216] The particle flow shear force and cohesion force were measured using a dynamic powder flow meter (Mercury, Revolution). Specifically, after filling 25 cc of the particles inside a 100 cc drum, the potential energy of the particles inside the drum was measured using a camera while rotating at 0.3 rpm. At this time, when the avalanche (avalanche: a shape in which particles rise and collapse like a drum) of the particles inside the drum occurred 100 times, the average values ​​of the Cohesion Thickness (shear force between stationary and flowing particles when the drum rotates) and Break Energy (energy for stationary particles to form an avalanche) were obtained.

[0217] 9. Measurement of binder performance and fiberization

[0218] In order to evaluate the fiberization performance of the particles, a mixture containing 96 wt% of the active material (NCM622 (nickel / cobalt / manganese = 6 / 2 / 2 wt%)), 2 wt% of the conductive material (Ketjen Black), and 2 wt% of each of the particles of the following examples and comparative examples as a binder was prepared.

[0219] Afterwards, the mixture was ground at 24,000 rpm using a blender (Kochstar, KSEBD-1500), and when the grinding was completed, it was kneaded at an internal temperature of 150 ℃ and a rotation speed of 15 rpm for 3 minutes using a batch mixer (HAAKE, Rheomix 600). Thereafter, the dough including the core-shell particles of Example 1 was photographed using a scanning electron microscope (SEM) as shown in FIG. 9, and the dough including the single core-shell particles of Comparative Example 1 was photographed using a scanning electron microscope (SEM) as shown in FIG. 10.

[0220] In addition, the total mass of the kneaded sample was measured, and the dough was first sieved through a sieve with a mesh size of 6.3 mm, and then secondarily sieved through a sieve with a mesh size of 4.75 mm. After the first and second sieving, the binder performance was determined as the weight % of the dough sample having a mesh size of 6.3 mm or more (separated by the first sieve), 4.75 mm or more to less than 6.3 mm (separated by the second sieve), or less than 4.75 mm (not separated by the first and second sieves) with respect to the total amount of the kneaded sample.

[0221] Acrylic resin particle manufacturing

[0222] [Manufacturing Example 1]

[0223] In a 1 L reactor, 744.4 g of deionized water, 115.2 g of methyl methacrylate (MMA), and 28.8 g of n-butylacrylate (nBA) were charged, 11.6 g of Tergitol TMN-100X (90% aqueous solution) from DOW as an emulsifier, 0.14 g of ammonium persulfate as an initiator, and 0.32 g of n-octyl mercaptan as a chain transfer agent were added, and the mixture was stirred at a speed of 230 rpm while bubbling nitrogen, and the temperature was raised to 75 ° C. After reaching the polymerization temperature of 75 ° C, the nitrogen bubbling was stopped, and the polymerization reaction was performed for 3 hours, and then cooled to room temperature to prepare a second dispersion solution which is an emulsion containing acrylic resin particles. The results of analyzing the weight average molecular weight, glass transition temperature, and average particle size are listed in Table 1 below.

[0224] [Manufacturing Example 2]

[0225] Except that 100.8 g of methyl methacrylate (MMA), 21.6 g of methacrylic acid (MAA), and 21.6 g of n-butylacrylate (nBA) were added as monomers in the above Manufacturing Example 1, the same amounts were used and the experiment was conducted. The results of analyzing the weight average molecular weight, glass transition temperature, and average particle size are included in Table 1 below.

[0226] [Manufacturing Example 3]

[0227] The same amounts were used as in Manufacturing Example 1 above, except that 115.2 g of methyl methacrylate (MMA) and 28.8 g of styrene were added as monomers. The results of analyzing the weight average molecular weight, glass transition temperature, and average diameter are included in Table 1 below.

[0228] Tg[℃]Mw[kg / mol]Average particle size (D50)[nm]Monomer content (calculated value)Solid contentPreparation example 182.2139594MMA 80 wt%nBA 20 wt%17.2Preparation example 284.5186681MMA 70 wt%MAA 15 wt%nBA 15 wt%17.2Preparation example 378.7120567MMA 80 wt%Styrene 20 wt%17.2

[0229] Core-shell particle manufacturing

[0230] [Example 1]

[0231] In a 1 L reactor, 291.2 g of deionized water, 291.2 g of methanol, and 4.5 g of calcium acetate monohydrate (Ca(OAc)2*H2O) as a coagulant were charged, stirred at a speed of 300 rpm, and the reactor temperature was raised to 60°C. To the heated reactor, 168 g of a polytetrafluoroethylene (PTFE) aqueous dispersion (Chemours, DISP30, average particle size (D50): 0.22 μm, solid content: 63.5%) as a first dispersion solution was added dropwise at a speed of 5.6 g / min using a dropping funnel, thereby forming an aggregate-like core in the solvent of the reactor.

[0232] Thereafter, 157 g of the dispersion solution of Manufacturing Example 1 was continuously added dropwise to the reactor at a rate of 15.8 g / min using a dropping funnel to form a shell layer on the surface of the aggregate-shaped core, and aged at 80°C for 1 hour. After the aging was completed, the core-shell particles were cooled to room temperature, washed sufficiently using deionized water, and dried in a vacuum oven at 50°C for 24 hours to obtain core-shell particles.

[0233] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0234] [Example 2]

[0235] In a 1 L reactor, 320.0 g of deionized water, 320.0 g of methanol, and 6.9 g of calcium acetate monohydrate (Ca(OAc)2*H2O) as a coagulant were charged, stirred at a speed of 300 RPM, and the reactor temperature was raised to 60°C. 189.0 g of a polytetrafluoroethylene (PTFE) aqueous dispersion (Chemours, DISP30, average particle size (D50): 0.22 μm) as a first dispersion solution was added dropwise to the heated reactor at a speed of 6.3 g / min using a dropping funnel, thereby forming an aggregate-like core in the solvent of the reactor.

[0236] Thereafter, 78.8 g of the dispersion solution of Manufacturing Example 1 was continuously added dropwise to the reactor at a rate of 7.9 g / min using a dropping funnel to form a shell layer on the aggregate-shaped core, and aged at 80°C for 1 hour. After the aging was completed, the mixture was cooled to room temperature, thoroughly washed with deionized water, and dried in a vacuum oven at 50°C for 24 hours to obtain core-shell particles.

[0237] That is, in the above Example 1, it was manufactured in the same manner as in Example 1 except that the first dispersion solution and the dispersion solution of Preparation Example 1 were added in a weight ratio of 1:0.42.

[0238] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0239] [Example 3]

[0240] In the above Example 1, core-shell particles were manufactured in the same manner as in Example 1 except that the reactor stirring speed was set to 200 rpm.

[0241] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0242] [Example 4]

[0243] In the above Example 1, core-shell particles were manufactured in the same manner as in Example 1 except that the reactor stirring speed was set to 500 rpm.

[0244] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0245] [Example 5]

[0246] Core-shell particles were prepared in the same manner as in Example 1 above, except that a first dispersion solution having a solid content of 63.5% was used, which was prepared by dispersing PTFE particles (Sigma-Aldrich) having an average particle diameter of 40 μm in deionized water.

[0247] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0248] [Example 6]

[0249] Core-shell particles were prepared in the same manner as in Example 1 above, except that a first dispersion solution having a solid content of 63.5% was used, which was prepared by dispersing PTFE particles (Sigma-Aldrich) having an average particle diameter of 1 μm in deionized water.

[0250] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0251] [Example 7]

[0252] In the above Example 1, core-shell particles were manufactured in the same manner as in Manufacturing Example 1, except that the dispersion solution of Manufacturing Example 2 was used instead of the dispersion solution of Manufacturing Example 1.

[0253] The properties of the aggregate-type core particles manufactured thereafter were measured using the above measurement method, and are shown in Tables 3 and 4 below.

[0254] [Example 8]

[0255] Core-shell particles were manufactured in the same manner as in Example 1 above, except that the dispersion solution of Manufacturing Example 3 was used instead of the dispersion solution of Manufacturing Example 1.

[0256] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0257] [Example 9]

[0258] In the above Example 1, core-shell particles were manufactured in the same manner as in Example 1 except that an aqueous solution containing 407.7 g of deionized water and 174.7 g of methanol was used in a weight ratio of 1:0.43.

[0259] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0260] [Example 10]

[0261] In the above Example 1, core-shell particles were manufactured in the same manner as in Example 1 except that ethanol was used instead of methanol as the organic solvent.

[0262] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0263] [Example 11]

[0264] In the above Example 1, core-shell particles were manufactured in the same manner as in Example 1 except that 7.1 g of aluminum nitrate nonahydrate was added instead of calcium acetate monohydrate (Ca(OAc)2*H2O) as a coagulant, and the concentration of the coagulant in the aqueous solution was made 1.20 wt%.

[0265] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0266] [Comparative Example 1]

[0267] An aqueous PTFE dispersion (Chemours, DISP-30) with an average particle diameter of 0.21 ㎛, a solid concentration of 30%, and a Standard Specific Gravity (SSG) of 2.16 to 2.22 was prepared. Next, 2448.0 g of the PTFE dispersion and 48.96 g of a 90% aqueous solution of polyethylene glycol trimethylnonyl ether, in which the molecular weight of the ethylene glycol repeating unit exhibiting hydrophilicity is 384 g / mol, were placed in a 4-liter reactor and stirred at 350 rpm while bubbling nitrogen, and the temperature was raised to 75°C. When the temperature reached 75 ℃, nitrogen bubbling was stopped, and after 15 minutes, a monomer mixture formed by 223.20 g of methyl methacrylate (MMA), 55.08 g of n-butylacrylate (nBA), and additionally 0.40 g of normal octyl mercaptan as a chain transfer agent was added dropwise over 15 minutes, and 15 minutes after the addition of the monomer mixture, 68.4 g of distilled water and 0.92 g of potassium persulfate aqueous solution were added dropwise to the reactor over about 10 minutes. After the completion of the addition of potassium persulfate, the polymerization reaction was carried out for 3 hours, and then cooled to 30 ℃ to obtain a white emulsion. In addition, the emulsion was freeze-dried for 72 hours under the conditions of -60 ℃ and 10 mTorr to obtain a white powder.

[0268] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0269] [Comparative Example 2]

[0270] Polytetrafluoroethylene (PTFE) powder (Chemours, 601X) having an average particle diameter similar to that of the aggregate-type core of Example 1 was used. The average particle diameter (D50) of the polytetrafluoroethylene (PTFE) powder (Chemours, 601X) measured on TDS was 532 μm.

[0271] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0272] [Comparative Example 3]

[0273] In the above Example 1, core-shell particles were manufactured in the same manner as in Example 1 except that no organic solvent was added to the reactor and 582.4 g of deionized water was used.

[0274] The properties of the aggregate-type core particles manufactured thereafter were measured using the above measurement method, and are shown in Tables 3 and 4 below.

[0275] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0276] [Comparative Example 4]

[0277] Core-shell particles were prepared in the same manner as in Example 1 above, except that no coagulant was used.

[0278] After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0279] [Comparative Example 5]

[0280] In a 1 L reactor, 291.2 g of deionized water, 291.2 g of methanol, and 4.5 g of calcium acetate monohydrate (Ca(OAc)2*H2O) as a coagulant were charged, stirred at a speed of 300 RPM, and the reactor temperature was raised to 60 ℃. 168.0 g of a polytetrafluoroethylene (PTFE) aqueous dispersion (Chemours, DISP30, average particle size (D50): 0.22 ㎛) as a first dispersion solution was added dropwise to the heated reactor at a speed of 5.6 g / min using a dropping funnel, thereby obtaining an aggregate-type core in the solvent in the reactor. After maintaining it at 60 ℃ for 10 minutes, it was cooled to room temperature, washed sufficiently with deionized water, and dried in a vacuum oven at 50 ℃ for 24 hours to obtain particles.

[0281] That is, only the aggregate-type core that did not form a shell layer was manufactured in Example 1. After that, the physical properties were measured using the above measurement method and are shown in Tables 3 and 4 below.

[0282] Agglomerate core formation stepShell layer formation stepOrganic solvent:Organic solvent (weight ratio)CoagulantCoagulant concentration (weight %)Stirring speed (rpm)PTFE resin particle (㎛)Acrylic resin particle input amount (weight ratio of first and second dispersion solutions)Example 1Methanol 1:1Calcium acetate monohydrate0.773000.2Preparation example 11:0.942Methanol 1:1Calcium acetate monohydrate0.773000.2Preparation example 11:0.423Methanol 1:1Calcium acetate monohydrate0.772000.2Preparation example 11:0.944Methanol 1:1Calcium acetate monohydrate0.775000.2Preparation example 11:0.945Methanol 1:1Calcium acetate Monohydrate 0.7730040.0 Manufacturing Example 11:0.946 Methanol 1:1 Calcium acetate monohydrate 0.773001.0 Manufacturing Example 11:0.947 Methanol 1:1 Calcium acetate monohydrate 0.773000.2 Manufacturing Example 21:0.948 Methanol 1:1 Calcium acetate monohydrate 0.773000.2 Manufacturing Example 31:0.949 Methanol 1:0.43 Calcium acetate monohydrate 0.773000.2 Manufacturing Example 11:0.9410 Ethanol 1:1 Calcium acetate monohydrate 0.773000.2 Manufacturing Example 11:0.9411 Methanol 1:1 Aluminum nitrate nonahydrate 1.203000.2 Manufacturing Example 11:0.94 Comparative Example 1 Single core-shell particle 2 Single PTFE particle 3 No organic solvent used Calcium acetate monohydrate 0.77 300 0.2 Manufacturing Example 11:0.94 4 Methanol 1:1 No coagulant used - 300 0.2 Manufacturing Example 11:0.94 5 Methanol 1:1 Calcium acetate monohydrate 0.77 300 0.2 No shell formation

[0283] Classification (aggregate type) Core-shell layerCore-shell particleAverage particle size (D50) (SEM)PTFE content (TGA)Shell thickness (SEM)Average particle size (D50) (Mastersizer)Average particle size Span (Mastersizer)Core aggregate surface cover (SEM)Unit (㎛)Wt% (㎛) (㎛)No unitNo unitExample1970817011031.26○285091609741.22○370080508301.20○41200828013351.33○51000806511301.38○61000807011401.2 7○71040807011661.27○8920786010451.23○9890816010201.38○10930826510511.31○11100817012271.45○Comparative Example 10.23(TEM)800.01(TEM)0.261.13○261099No shell layer formed6101.3X385094Insufficient shell layer formed9602.06X497095Insufficient shell layer formed11002.60X599099No shell layer formed9842.71X

[0284] Classification Flowability Storage Stability Binding Performance - Fiberization BFE (FT4) SE (FT4) Cohesion Thickness Break Energy Caking Test Lump Sieve 1 (Coarse Particles) Sieve 2 (Medium Particles) Pan (Fine Particles) Particle) Unit mJ mJ / gmJ / kg mJ / kg %%%% Example 15 123.217.349.80 98.90.50.626804.320.952.80 98.90.90.236173.924.561.50 96.52.11.445763.622.350.1096.71.12.256173.924.561.50 96.52.11.465954.225.052.1096.51.32.276444.016.449.50 98.80.40.884983.118.45 9.3097.31.61.196043.818.551.6097.50.61.9106213.917.650.4098.60.50.9115563.521.455.2098.90.30.8Comparative Example 111505.875.087.5120.3099.72I / LI / L4161656099.00.20.83I / LI / L3951434198.20.51.34I / LI / L3561235598.60.41.05I / LI / L402151.86199.100.9

[0285] Figure 3 below is an optical microscope photograph of the aggregated core of Example 1, and Figure 4 below is a scanning electron microscope photograph of the aggregated core of Example 1. As can be seen from Figures 3 and 4 below, it can be confirmed that in Example 1, the fluorine-based resin particles are well aggregated to form an aggregated core.

[0286] The following Figure 5 is a photograph of the aggregated core of Example 1 taken using a scanning electron microscope, and as shown in the following Figure 6, it can be confirmed that the core-shell particle of Example 1 has a well-formed shell layer due to the agglomeration of the acrylic shell layer.

[0287] In addition, FIG. 6 below is a photograph taken using a scanning electron microscope after cutting the core-shell particle of Example 1 in half. By checking FIG. 6 below, it can be confirmed that the core-shell particle of Example 1 is formed with a clearly distinct aggregate-type core and shell layer.

[0288] In order to confirm that the core-shell particles of Example 1 are clearly formed with a distinctly distinct aggregate-type core and shell layer, the core-shell particles of Example 1 are photographed by SEM-EDX as shown in Fig. 7 below. The PTFE resin particles are dark gray (substantially blue), and the acrylic resin particles of Manufacturing Example 1 are shown in light gray (substantially green). It can be confirmed that the core-shell particles have a perfect core-shell particle form in which only the PTFE resin particles are distributed in the aggregate-type core and only the acrylic resin particles are distributed in the shell layer. Furthermore, when checking the SEM-EDX image of Fig. 7 below, it can be confirmed that the core-shell particles of Example 1 are completely coated with a shell layer of 100% with respect to the total surface area of ​​the aggregate-type core.

[0289] Accordingly, when checking Table 3 above, it was confirmed that in Examples 1 to 11, fluorine-based resin particles were all aggregated to form an aggregate-type core, and acrylic resin particles were aggregated on the surface of the formed aggregate-type core to form a shell layer, thereby forming a core-shell particle composed of an aggregate-type core formed by well-aggregating fluorine-based resin particles and a shell layer formed by well-aggregating acrylic resin particles.

[0290] In addition, in Table 3 above, when examining the core-shell particles manufactured in Examples 3 and 4, it was confirmed that the average particle diameter of the aggregated core and the average particle diameter of the core-shell particles could be controlled by controlling the stirring speed, and in addition, when examining Example 2 above, it was confirmed that the content of the shell layer could be controlled by controlling the content of the polytetrafluoroethylene (PTFE) aqueous dispersion solution and the acrylic resin particle solution.

[0291] In addition, when the core-shell particles of Examples 5 and 6 are confirmed in Table 3 above, even if the average particle diameter of the fluorine-based resins is changed, the fluorine-based resin particles are well aggregated to produce an aggregate-type core and core-shell particles including the same.

[0292] As in the core-shell particles of Examples 7 and 8 in Table 3 above, it was confirmed that a shell layer could be formed from acrylic resin particles manufactured by further including styrene or (meth)acrylic acid.

[0293] Therefore, the core-shell particles manufactured in Examples 1 to 11 have a core-shell particle shape in which fluorine-based resin particles are aggregated to form an aggregate-type core, and acrylic-based resin particles are aggregated to form a shell layer on the surface of the aggregate-type core, so that the core-shell particle shape has a clearly distinguishable aggregate-type core and shell layer, and it was confirmed that the shell layer is uniformly formed on the surface of the aggregate-type core.

[0294] In addition, it was confirmed that the core-shell particles manufactured in Examples 1 to 11 were well formed regardless of the average particle diameter of the fluorine-based resin particles and the acrylic-based resin particles and the monomer manufactured into the acrylic-based resin particles.

[0295] In addition, it was confirmed that the core-shell particles manufactured in Examples 1 to 11 can be easily controlled in terms of the average particle diameter of the core-shell particles, the average particle diameter of the aggregated core, and the thickness of the shell layer by controlling the stirring speed of the reactor and the weight ratio of the first dispersion solution and the second dispersion solution, and it was confirmed that the average particle diameter Span value of the core-shell particles has a value of 1.5 or less.

[0296] Since the average particle diameter Span value of the core-shell particles is 1.5 or less, this means that the average particle diameter distribution is very narrow, which means that the core-shell particles of the present disclosure may have a very uniform average particle diameter.

[0297] Therefore, the core-shell particle according to one aspect of the present disclosure has the physical properties described above, and thus can have the effects of excellent flowability, excellent binder properties, and excellent storage stability, which will be described later.

[0298] When examining Examples 1 to 11 of Table 4 above, it was confirmed that the core-shell particles of the aggregated type of Examples 1 to 11 had both low flow total energy (Basic Flowability Energy, BFE) and cohesive energy (Specific Energy, SE) measured by FT4, and also that the measured Cohesion Thickness (shear force between stationary and flowing particles when the drum rotates) and Break Energy (energy for stationary particles to form an avalanche) were very low in the dynamic fluid flow meter measured by Revolution.

[0299] That is, the aggregated core-shell particles manufactured in Examples 1 to 11 above prevent the fluorine-based resin particles included in the aggregated core from agglomerating with each other in advance, suggesting that the aggregated core-shell particles can have excellent flowability.

[0300] In addition, in Table 4 above, it was confirmed that the core-shell particles of Examples 1 to 11 not only had the excellent flowability described above, but also had excellent storage stability by not clumping together even when left under high pressure.

[0301] Furthermore, the core-shell particles of Examples 1 to 11 in Table 4 above have the excellent flowability and storage stability described above, and not only can have excellent storage stability, but also, in order to use them as electrode binders, it was confirmed that the electrode mixture prepared by including the core-shell particles has excellent binder properties in which 95 wt% or more is filtered through a primary sieve having a pore size of 6.3 mm or more.

[0302] In contrast, in Tables 3 and 4 above, it was confirmed that Comparative Examples 3 and 4 not only did not form a well-formed aggregate-type core, but also the acrylic resin particles did not aggregate to form a shell layer.

[0303] Accordingly, the particles of Comparative Examples 3 and 4 were aggregated to a level where static flowability measured by FT4 was impossible to measure, and the measured Cohesion Thickness and Break Energy were confirmed to be higher than those of the examples in the dynamic flow meter measured by Revolution. In addition, naturally, when checking Table 3 above, it was confirmed that the particles of Comparative Examples 2 and 5, which did not form a shell layer, had poor flowability to the extent that measurement was impossible.

[0304] In addition, in Tables 3 and 4 above, Comparative Example 1 is a single core-shell particle in which an acrylic resin is polymerized on the surface of a single PTFE particle to form a shell layer, and it was confirmed that the cohesion between the particles was very high compared to the examples, the storage stability was low, and in particular, the binder property was very low compared to the examples.

[0305] Therefore, the core-shell particle manufacturing method can prevent the fluorine-based resin particles from agglomerating with each other in advance, thereby not only achieving remarkably excellent flowability and excellent storage stability, but also achieving superior binder properties compared to conventional single core-shell particles. Accordingly, the core-shell particles can be usefully used as an anti-dripping agent, powder coating, fiber coating material, automobile parts, or electrode binder.

[0306] As described above, the present disclosure has been described by specific matters and limited examples and comparative examples, but these are provided only to help a more general understanding of the present disclosure, and the present disclosure is not limited to the above examples, and those of ordinary skill in the art to which the present disclosure pertains can make various modifications and variations based on this description.

[0307] Therefore, the idea of ​​the present invention should not be limited to the described embodiments, and all things that are equivalent or equivalent to the claims described below as well as the claims are considered to fall within the scope of the idea of ​​the present invention.

[0308] (Symbol explanation)

[0309] 100: Core-shell particles

[0310] 10: Agglomerated core

[0311] 11: Fluorine resin particles

[0312] 20: Shell layer

[0313] 21: Acrylic resin particles

Claims

1. An aggregate-type core formed by the agglomeration of fluorine-based resin particles; A core-shell particle comprising a shell layer formed by agglomerating acrylic resin particles on the surface of the aggregate-type core. The above core-shell particles are core-shell particles having an average particle diameter (D50) of 500 to 3,000 ㎛.

2. In paragraph 1, The above fluorine-based resin particles are core-shell particles comprising a fluorine-based polymer polymerized with one or more fluorinated monomers selected from vinylidene difluoride, vinyl fluoride, chlorotrifluoroethylene, tetrafluoroethylene, perfluoroalkyl vinyl ether, and hexafluoropropylene.

3. In paragraph 2, The above fluorine-based polymer is a core-shell particle polymerized with one or more selected from tetrafluoroethylene, perfluoroalkyl vinyl ether, and hexafluoropropylene.

4. In paragraph 1, The above acrylic resin particles are core-shell particles comprising one or more selected from a methyl methacrylate homopolymer; and an acrylic copolymer of one or more comonomers selected from methyl methacrylate and ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, iso-butyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and styrene monomers.

5. In paragraph 4, The above acrylic resin particles are core-shell particles containing an acrylic copolymer.

6. In paragraph 4, The above acrylic copolymer is a core-shell particle having 70 to 99.9 wt% of methyl methacrylate polymerization units based on 100 wt% of total polymerization units.

7. In paragraph 1, The above-mentioned aggregate-type core is an aggregate in which fluorine resin particles having an average particle diameter (D50) of 0.01 to 100 ㎛ are closely aggregated with each other. Core-shell particles having an average particle diameter (D50) of the above aggregate-type core of 200 to 2,500 ㎛.

8. In paragraph 7, The above fluorine-based resin particles are core-shell particles having an average particle diameter (D50) of 0.1 to 50 ㎛.

9. In paragraph 1, Core-shell particles having a thickness of the shell layer of 50 to 500 μm.

10. In paragraph 1, The above acrylic resin particles are core-shell particles having an average particle diameter (D50) of 0.01 to 100 ㎛.

11. In paragraph 10, The above acrylic resin particles are core-shell particles having an average particle diameter (D50) of 0.1 to 50 ㎛.

12. In paragraph 1, The core-shell particle is a core-shell particle comprising a shell layer in an amount of 1 to 50 wt% based on the total weight.

13. In paragraph 1, The core-shell particle is a core-shell particle in which the shell layer is coated at 90% or more of the total surface area of ​​the aggregated core.

14. In paragraph 13, The core-shell particle is a core-shell particle in which the shell layer is coated at 100% of the total surface area of ​​the aggregated core, excluding the voids between the acrylic resin particles.

15. In paragraph 1, The core-shell particles are core-shell particles comprising one or more coagulants selected from acetate, sulfate and nitrate.

16. In paragraph 1, The core-shell particles are core-shell particles having a shear force (Cohesion Thickness) between a stationary core-shell particle and a flowing core-shell particle of 50 mJ / ㎏ or less, measured 100 times at 0.3 rpm using a dynamic powder flow meter from Mercury.

17. In paragraph 1, The core-shell particles are core-shell particles having a break energy of 100 mJ / ㎏ or less for forming an avalanche when measured 100 times at 0.3 rpm using a dynamic powder flow meter from Mercury.

18. In paragraph 1, The above core-shell particles are core-shell particles having a basic flowability energy (BFE) of 1,000 mJ or less and a specific energy (SE) of 10 mJ / ㎏ or less, as measured by a flow rheological characteristic measuring device of Freeman Tech.

19. A combination comprising core-shell particles selected from any one of claims 1 to 18.

20. In paragraph 19, The above combination is a combination containing an electrode active material.

21. In paragraph 19, The above formulation comprises core-shell particles in an amount of 0.1 to 20 wt% based on the total weight.

22. In paragraph 19, The above mixture is a mixture that is filtered at 95 wt% or more through a 6.3 mm sieve.

23. A step of forming an aggregate-type core by adding a first dispersion solution in which fluorine-based resin particles are dispersed into an aqueous solution containing an organic solvent and a coagulant, and the fluorine-based resin particles are coagulated; and A method for manufacturing core-shell particles, comprising the step of introducing a second dispersion solution in which acrylic resin particles are dispersed into an aqueous solution in which the aggregate-type core is formed, so that the acrylic resin particles aggregate on the surface of the core aggregate to form a shell layer; The above-mentioned aggregate-type core is a core-shell particle manufacturing method having an average particle diameter (D50) of 200 to 2,500 ㎛.

24. In paragraph 23, A method for producing core-shell particles in which the organic solvent is a C1-C7 aliphatic alcohol, a C1-C4 alkyl acetic acid or a mixed solvent thereof.

25. In paragraph 23, A method for producing core-shell particles, wherein the aqueous solution is a mixture of deionized water and an organic solvent in a weight ratio of 1:0.1 to 9.

26. In paragraph 23, A method for producing core-shell particles, wherein the coagulant is one or more selected from acetate, sulfate, and nitrate.

27. In paragraph 23, A method for producing core-shell particles, wherein the coagulant is included in an aqueous solution at a concentration of 0.1 to 5 wt%.

28. In paragraph 23, A method for producing core-shell particles, wherein the step of forming the above-mentioned aggregate-type core comprises adding 10 to 60 parts by weight of the first dispersion solution to 100 parts by weight of the aqueous solution.

29. In paragraph 23, A method for producing core-shell particles in which the step of forming the above-mentioned aggregate-type core is performed at a stirring speed of 100 to 1,000 rpm.

30. In paragraph 23, A method for producing core-shell particles, wherein the step of forming the above-mentioned aggregate-type core is to aggregate fluorine-based resin particles at 40 to 90°C.

31. In paragraph 23, A method for producing core-shell particles, wherein the first dispersion solution has a solid content of 30 to 80 wt% based on the total weight.

32. In paragraph 23, A method for producing core-shell particles, wherein the step of forming the shell layer comprises forming a shell layer by coagulating acrylic resin particles at 50 to 90°C.

33. In paragraph 23, A method for producing core-shell particles, wherein the second dispersion solution has a solid content of 10 to 50 wt% based on the total weight.

34. In paragraph 23, The above core-shell particle manufacturing method is a core-shell particle manufacturing method in which the weight ratio of the first dispersion solution and the second dispersion solution to be introduced is 1:0.1 to 1.5.

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