Core-shell type fluoropolymer particles with improved binding properties

Abstract

This invention relates to core-shell particles (or core-shell particle type binders), compositions comprising core-shell particles (or core-shell particle type binders), or electrodes made from such compositions, wherein the core-shell particles have a perfluorinated resin core comprising a perfluorinated polymer and a resin shell comprising an acrylic polymer, wherein the core-shell particles are prepared by emulsifying an acrylic monomer to the perfluorinated resin core using a polyethylene glycol ether of Formula 1 having at least one alkyl-substituted C8 or larger alkyl group as an emulsifier, and the acrylic monomer comprises (a) methyl methacrylate (MMA), (b) methacrylic acid (MAA) or acrylic acid (AA) and (c) C2-C6 alkyl (meth)acrylate.

Description

Technical Field

[0001] The following disclosure relates to core-shell particles (or core-shell particle binders) having a perfluorinated resin core comprising a perfluorinated polymer and a resin shell comprising an acryloyl-based polymer, compositions comprising the core-shell particles, or electrodes made from the compositions.

[0002] When a core-shell particle (or core-shell particle binder) according to an exemplary embodiment of the present invention is used as a binder for electrode active materials, a sufficient amount of binder can be provided to impart bonding force or adhesive strength between electrode active materials, even when using a small amount of perfluorinated resin core and a low content of core-shell particles.

[0003] Furthermore, the core-shell particles according to an exemplary embodiment of this disclosure can have a very uniform particle size distribution, a very uniformly formed shell, and provide excellent bonding performance. Background Technology

[0004] Perfluorinated resins, including polytetrafluoroethylene (PTFE), can be used as various adhesives, process modifiers, fluidizing agents, etc., due to their electrical, thermal, and binding properties.

[0005] For example, perfluorinated resins can be used in combination with other materials as coating materials for semiconductor manufacturing devices, coating materials on various substrates in electronic storage devices, adhesive materials, etc. Furthermore, research is underway to improve performance by forming a shell on the surface of particles using resins with different physical properties or by means of surface modification, thereby improving properties during use.

[0006] In other words, in order to improve the surface properties while utilizing the properties of the perfluorinated resin as is, a manufacturing technology for core-shell particles with a non-fluorinated resin shell as the surface layer of the perfluorinated resin has been developed.

[0007] Japanese Patent Publication No. JP 2019-112620 A discloses core-shell particles having a core containing a perfluoropolymer and a shell containing a non-fluorinated resin to provide core-shell particles with excellent dispersibility. However, particles in which the shell does not completely surround the core may still be formed. Furthermore, they do not exhibit sufficient adhesive strength. Therefore, the particles do not have sufficient properties to be used as a binder for electrode active materials. Summary of the Invention

[0008] Technical issues

[0009] The purpose of this disclosure is to provide new core-shell particles (or core-shell granular adhesives) that, compared to conventional perfluorinated resins and core-shell particles or core-shell granular adhesives containing such resins, have a perfluorinated resin core with further improved adhesive strength to electrode active materials, etc., and a resin shell layer containing an acryloyl-based polymer.

[0010] Technical solution

[0011] In one general aspect, the core-shell particles comprise: a perfluorinated resin core comprising a perfluorinated polymer and a resin shell comprising an acryloyl-based polymer, wherein the core-shell particles are manufactured by emulsifying an acryloyl-based monomer to the perfluorinated resin core using a polyethylene glycol ether of Formula 1 having one or more alkyl-substituted C8 or higher alkyl groups as an emulsifier, and the acryloyl-based monomer comprises: (a) methyl methacrylate; (b) methacrylic acid or acrylic acid; and (c) C2 to C6 alkyl (meth)acrylates.

[0012] [Chemical Formula 1]

[0013] R-(-O-C2H4-) n -OH

[0014] Where R is a C8 or higher alkyl group substituted with one or more alkyl groups, and n is an integer from 5 to 15.

[0015] In one exemplary embodiment, chemical formula 1 can be an emulsifier of chemical formula 2:

[0016] [Chemical Formula 2]

[0017]

[0018] In one exemplary embodiment, the perfluoropolymer may be polytetrafluoroethylene.

[0019] In one exemplary embodiment, the core-shell particles may comprise a perfluoropolymer and an acryloyl-based polymer in a weight ratio of 98:2 to 30:70.

[0020] In one exemplary embodiment, the core-shell particles may comprise a perfluoropolymer and an acryloyl-based polymer in a weight ratio of 80:20 to 40:60.

[0021] In one exemplary embodiment, the core-shell particles may contain 20% to 40% by weight of methyl methacrylate in an acryloyl-based monomer.

[0022] In one exemplary embodiment, the core-shell particles may contain 30% to 50% by weight of methacrylic acid or acrylic acid in an acryloyl-based monomer.

[0023] In one exemplary embodiment, the core-shell particles may contain 20% to 40% by weight of C2 to C6 alkyl (meth)acrylates in an acryloyl-based monomer.

[0024] In another general aspect, the composition comprises the core-shell particles and the electrode active material.

[0025] In another general aspect, an electrode made from the composition is provided.

[0026] In yet another general aspect, the battery includes the core-shell particles as a binder.

[0027] Beneficial effects

[0028] The core-shell particles according to an exemplary embodiment of this disclosure exhibit excellent bonding properties with other materials and provide excellent physical adhesive properties, electrical properties, and surface properties even with the use of small amounts of perfluorinated polymers such as polytetrafluoroethylene (PTFE). Furthermore, excellent adhesive performance is also observed even with small amounts of core-shell granular binder.

[0029] The core-shell particles according to an exemplary embodiment of this disclosure can provide a core-shell particle-like binder having a uniform particle size distribution and a very uniformly formed shell layer, and can also provide a novel binder with excellent adhesive strength for adhering particulate particles such as electrode active materials.

[0030] That is, the core-shell particles (or core-shell granular adhesives) according to an exemplary embodiment of the present disclosure have excellent bonding properties with other materials such as metals or conductive particles, and even when using a small amount of perfluorinated resin core and a small amount of core-shell granular adhesive, they have the effect of providing core-shell particles (or core-shell granular adhesives) with excellent adhesive properties.

[0031] Furthermore, the core-shell particles according to an exemplary embodiment of this disclosure are manufactured by emulsion polymerization of acryloyl-based monomers using a polyethylene glycol ether of the following chemical formula 1 having one or more alkyl-substituted C8 or higher alkyl groups as an emulsifier, thereby forming uniform particle size and a uniform shell layer, such that the core, such as a fluoropolymer, is not exposed on the surface of the particles:

[0032] [Chemical Formula 1]

[0033] R-(-O-C2H4-)n -OH

[0034] Where R is a C8 or higher alkyl group substituted with one or more alkyl groups, and n is an integer from 5 to 15.

[0035] The monomers forming the shell layer in the core-shell particles are acryloyl-based monomers, and the acryloyl-based monomers include (a) methyl methacrylate (MMA); (b) methacrylic acid (MAA) or acrylic acid (AA); and (c) C2 to C6 alkyl (meth)acrylates.

[0036] Furthermore, since the core-shell particles and core-shell particulate binder of an exemplary embodiment of this disclosure have excellent affinity with other materials, such as electrode active materials, they can exhibit the excellent binding properties of conventional fluoropolymers even when the content of the perfluoropolymer (PTFE) forming the perfluorinated resin core is very small. Moreover, even with a small content of core-shell particulate binder, they can impart excellent binding properties to the electrode active material.

[0037] Furthermore, by containing a shell prepared by polymerizing acryloyl-based monomers, even with a small amount of fluoropolymer, the core-shell particles according to an exemplary embodiment of this disclosure have increased bonding strength with the metal current collector (e.g., Al foil) used as the current collector and the material (e.g., the electrode active material), thereby having the effect of further enhancing the physical properties of the electrode. Attached Figure Description

[0038] Figure 1 This is a photograph of the electrode dough prepared according to Example 1.

[0039] Figure 2 This is a particle shape analysis (FE-SEM) image of the electrode manufactured according to Example 1.

[0040] Figure 3 This is a photograph of the electrode paste prepared according to Comparative Example 1.

[0041] Figure 4 These are particle shape analysis (FE-SEM) images of the electrode manufactured according to Comparative Example 1. Detailed Implementation

[0042] In the following, core-shell particles (or core-shell granular binders) having a perfluorinated resin core comprising a perfluorinated polymer and a resin shell comprising an acryloyl-based polymer, compositions comprising the core-shell particles, or electrodes made from the compositions will be described.

[0043] Unless otherwise defined, the technical and scientific terms used in this specification have the general meanings understood by one of ordinary skill in the art to which this invention pertains, and descriptions of known functions and configurations that obscure the invention will be omitted in the following description.

[0044] Furthermore, unless otherwise stated in the context, the singular form used in this disclosure may be intended to include the plural form as well.

[0045] Furthermore, units used in this disclosure unless otherwise specifically mentioned are based on weight, and by way of example, unless otherwise defined, % or ratio refers to weight % or weight ratio, and weight % refers to the weight of any one component in the total composition.

[0046] Furthermore, the numerical ranges used in this disclosure include all values ​​within a range that includes both a lower and upper limit, increments derived logically from the form and span of the defined range, all values ​​with double constraints, and all possible combinations of upper and lower limits within a numerical range defined in different forms. Unless otherwise defined in the specification of this invention, values ​​that may exceed the defined numerical range due to experimental error or rounding are also included within the defined numerical ranges.

[0047] The term “comprising” in this disclosure is an open-ended description that has the same meaning as terms such as “providing,” “including,” “having,” or “characterized in,” and does not exclude elements, materials, or processes not further listed.

[0048] The term "(meth)acrylate" in this disclosure may refer to both methacrylate and acrylate.

[0049] Hereinafter, an exemplary embodiment of the present disclosure will be described, comprising core-shell particles (or core-shell particle binders) having a perfluorinated resin core comprising a perfluorinated polymer and a resin shell comprising an acryloyl-based polymer, a composition comprising the core-shell particles, or an electrode made from the composition.

[0050] This disclosure relates to core-shell particles (or core-shell granular binders) having a perfluorinated resin core comprising a perfluorinated polymer and a resin shell comprising an acryloyl-based polymer, wherein the core-shell particles (or core-shell granular binders) are manufactured by emulsifying an acryloyl-based monomer to the perfluorinated resin core using a polyethylene glycol ether of the following chemical formula 1 having one or more alkyl-substituted C8 or higher alkyl groups as an emulsifier.

[0051] In one exemplary embodiment, the acryloyl-based monomer comprises (a) methyl methacrylate (MMA); (b) methacrylic acid (MAA) or acrylic acid (AA); and (c) C2 to C6 alkyl (meth)acrylates.

[0052] [Chemical Formula 1]

[0053] R-(-O-C2H4-) n -OH

[0054] Where R is a C8 or higher alkyl group substituted with one or more alkyl groups, and n is an integer from 5 to 15.

[0055] In one exemplary embodiment according to this disclosure, chemical formula 1 may be an emulsifier of chemical formula 2, but is not limited thereto:

[0056] [Chemical Formula 2]

[0057]

[0058] In one exemplary embodiment, the emulsifier may be polyethylene glycol trimethyl nonyl ether, wherein the molecular weight of the hydrophilic ethylene glycol repeating unit is 384 g / mol, but is not limited thereto.

[0059] In one exemplary embodiment, the core-shell particles (or core-shell granular binders) can provide excellent particle shape, thereby obtaining core-shell particles (or core-shell granular binders) with a shell that uniformly surrounds the entire region of the core.

[0060] In one exemplary embodiment, the monomer forming the perfluorinated resin core is not particularly limited, as long as it is a perfluorinated unsaturated monomer, but may be, for example, a polymer or copolymer thereof prepared from a monomer selected from tetrafluoroethylene (TFE), perfluoro(alkyl vinyl ether), hexafluoropropylene, etc., but is not limited thereto.

[0061] In one exemplary embodiment, examples of the perfluorinated polymer forming the perfluorinated resin core may be selected from at least one of the following: polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE) / perfluoro(alkyl vinyl ether) copolymer (PFA), and TFE / hexafluoropropylene copolymer (FEP), but are not limited thereto.

[0062] In one exemplary embodiment, the perfluoropolymer may be polytetrafluoroethylene, but is not limited thereto.

[0063] In one exemplary embodiment, the resin forming the resin shell can be a resin based on poly(meth)acrylate, but is not limited thereto.

[0064] In one exemplary embodiment, when core-shell particles (or core-shell particulate binders) are manufactured by polymerization, they can be manufactured by conventionally known methods, such as emulsion polymerization, solution polymerization, or suspension polymerization by properly mixing a perfluorinated resin core and an additive (e.g., a polymerization initiator), but are not limited thereto.

[0065] In one exemplary embodiment, the core-shell particles (or core-shell granular binder) may comprise a perfluoropolymer and an acryloyl-based polymer in the following weight ratios: 98:2 to 30:70, 95:5 to 30:70, 95:5 to 40:60, 95:5 to 50:50, 95:5 to 60:40, 95:5 to 70:30, 95:5 to 80:20, 90:10 to 30:70, 90:10 to 40:60. The ratios are 90:10 to 50:50, 90:10 to 60:40, 90:10 to 70:30, 90:10 to 80:20, 80:20 to 30:70, 80:20 to 40:60, 80:20 to 50:50, 80:20 to 60:40, 80:20 to 70:30, 70:30 to 30:70, 70:30 to 40:60, 70:30 to 50:50, or 70:30 to 60:40. Specifically, the core-shell particles may contain a perfluoropolymer and an acryloyl-based polymer in a weight ratio of 98:2 to 30:70. Specifically, the core-shell particles may contain a perfluoropolymer and an acryloyl-based polymer in a weight ratio of 80:20 to 40:60. The core-shell particles of this disclosure exhibit excellent affinity for active materials and demonstrate superior binding properties with electrode active materials even when the ratio of perfluorinated resin core (e.g., perfluoropolymer (PTFE)) is low.

[0066] In one exemplary embodiment, the acryloyl-based monomer may include, but is not limited to, at least one of the following: butyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, methyl methacrylate, acrylic acid, methacrylic acid, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, and hexyl acrylate. Specifically, the acryloyl-based monomer may include: (a) methyl methacrylate (MMA); (b) methacrylic acid (MAA) or acrylic acid (AA); and (c) C2 to C6 alkyl (meth)acrylates. More specifically, the acryloyl-based monomer may include: (a) methyl methacrylate (MMA); (b) methacrylic acid (MAA); and (c) butyl acrylate.

[0067] The core-shell particles (or core-shell particulate adhesives) disclosed herein include: (a) methyl methacrylate (MMA), (b) methacrylic acid (MAA) or acrylic acid (AA), and (c) C2 to C6 alkyl (meth)acrylates as acryloyl-based monomers, thereby achieving excellent bonding properties when used as adhesives.

[0068] In one exemplary embodiment, the core-shell particles (or core-shell granular binder) may contain 10% or more, 20% or more, or 30% or more of methyl methacrylate in the acryloyl-based monomer. Methyl methacrylate may be contained in the acryloyl-based monomer in 60% or less, 50% or less, or 40% or less.

[0069] In one exemplary embodiment, the core-shell particles (or core-shell granular binder) may contain 10% to 60% by weight, 20% to 50% by weight, 20% to 40% by weight, or 30% to 40% by weight of methyl methacrylate in the acryloyl-based monomer. Specifically, methyl methacrylate may be included in the acryloyl-based monomer at 20% to 40% by weight.

[0070] In one exemplary embodiment, the core-shell particles (or core-shell granular binder) may contain 10% or more, 20% or more, or 30% or more of methacrylic acid or acrylic acid in the acryloyl-based monomer. The core-shell particles (or core-shell granular binder) may contain 60% or less, 50% or less, or 40% or less of methacrylic acid or acrylic acid in the acryloyl-based monomer.

[0071] In one exemplary embodiment, the core-shell particles (or core-shell granular binder) may contain 10% to 60% by weight, 30% to 50% by weight, 20% to 50% by weight, 20% to 40% by weight, or 30% to 40% by weight of methacrylic acid or acrylic acid in the acryloyl-based monomer. Specifically, the core-shell particles (or core-shell granular binder) may contain 30% to 50% by weight of methacrylic acid or acrylic acid in the acryloyl-based monomer.

[0072] In one exemplary embodiment, the core-shell particles (or core-shell granular binder) may contain 10% or more, 20% or more, or 30% or more of C2 to C6 alkyl (meth)acrylates in the acryloyl-based monomer. The core-shell particles (or core-shell granular binder) may contain 60% or less, 50% or less, or 40% or less of C2 to C6 alkyl (meth)acrylates in the acryloyl-based monomer.

[0073] In one exemplary embodiment, the core-shell particles (or core-shell granular binder) may contain 10% to 60% by weight, 30% to 50% by weight, 20% to 50% by weight, 20% to 40% by weight, or 30% to 40% by weight of C2 to C6 alkyl (meth)acrylates in the acryloyl-based monomer. Specifically, the acryloyl-based monomer may contain 20% to 40% by weight of C2 to C6 alkyl (meth)acrylates.

[0074] Furthermore, this disclosure relates to core-shell particle (or core-shell particle binder) slurry having a perfluorinated resin core comprising a perfluorinated polymer and a resin shell comprising an acryloyl-based polymer, wherein the core-shell particles (or core-shell particle binder) are manufactured by emulsifying an acryloyl-based monomer to the perfluorinated resin core using a polyethylene glycol ether of the following chemical formula 1 having one or more alkyl-substituted C8 or higher alkyl groups as an emulsifier, and the acryloyl-based monomer comprises: (a) methyl methacrylate (MMA); (b) methacrylic acid (MAA) or acrylic acid (AA); and (c) C2 to C6 alkyl (meth)acrylates.

[0075] [Chemical Formula 1]

[0076] R-(-O-C2H4-) n -OH

[0077] Where R is a C8 or higher alkyl group substituted with one or more alkyl groups, and n is an integer from 5 to 15.

[0078] In addition, this disclosure may provide compositions comprising core-shell particles (or core-shell granular binders).

[0079] In one exemplary embodiment, the composition may comprise an electrode active material. The core-shell particle-containing compositions of this disclosure exhibit excellent affinity for the active material and demonstrate excellent binding properties even when the proportion of perfluoropolymer (PTFE) contained in the core-shell particles is small.

[0080] This disclosure may provide compositions comprising core-shell particles (or core-shell particle binders) and electrode active materials.

[0081] Furthermore, this disclosure can provide electrodes manufactured from the composition.

[0082] This disclosure provides a battery incorporating core-shell particles (or core-shell particulate binders) as a binder. When these particles are used as a binder during battery manufacturing, the core-shell particles (or core-shell particulate binders) of this disclosure exhibit excellent bonding properties with the electrode active materials.

[0083] The invention will be described in more detail below with reference to embodiments and comparative examples. However, the following embodiments and comparative examples are merely examples for describing the invention in more detail and are not intended to limit the invention in any way. Unless otherwise stated in the invention, temperature is expressed in °C, and unless otherwise stated, the amount of the composition used is expressed in weight%.

[0084] 1. Measurement of total solids content [g / mol]

[0085] Weigh 15g of the polymerized latex onto an aluminum tray and dry it in an oven at 80°C for 24 hours. Then measure the weight after drying. The total solids content is calculated as (weight after drying - tray weight) / initial weight × 100.

[0086] 2. Extraction methods for non-fluorinated resins

[0087] 100g of the polymerized latex was placed in a 250ml centrifuge tube and centrifuged at 9,000 rpm for 30 minutes. The supernatant was discarded, and 100g of acetone was added to the remaining solid. The mixture was shaken for 3 hours to extract the non-fluorinated resin with acetone. After shaking for 3 hours, the mixture was centrifuged again at 9,000 rpm for 30 minutes. The fluorinated resin accumulated at the bottom, and the acetone supernatant containing the dissolved non-fluorinated resin was separated. The separated supernatant containing the dissolved non-fluorinated resin was added dropwise to 400g of methanol to obtain the precipitated non-fluorinated resin. The precipitated non-fluorinated resin was separated using a vacuum filter, washed three times with methanol, placed in a separate beaker, and dried in an oven at 80°C for 24 hours.

[0088] 3. Weight-average molecular weight (Mw) [g / mol]

[0089] To measure the molecular weight of the non-fluorinated resin in the latex prepared in the examples and comparative examples, 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 the molecular weight was measured using gel permeation chromatography (GPC) available from Waters.

[0090] 4. Glass transition temperature (Tg) [°C]

[0091] The non-fluorinated resins extracted from the latexes prepared in the examples and comparative examples were measured using differential scanning calorimetry (TA, Q20 DSC) at a heating rate of 10°C per minute over two cycles. The glass transition temperature was then calculated using the inflection point of the second cycle via the semi-Cp method.

[0092] 5. Measurement of the ratio between fluorinated resin and non-fluorinated resin

[0093] 15g of polymerized latex was placed on an aluminum tray and dried in an oven at 80°C. 10mg of the dried powder was heated to 600°C at 10°C per minute using a thermogravimetric analysis (TGA), and the weight loss was measured. The ratio between fluorinated and non-fluorinated resins was measured by the degree of weight loss, utilizing the thermal decomposition properties of the non-fluorinated resin.

[0094] 6. Measurement of particle size

[0095] One or two drops of latex after polymerization were diluted 1,000 times, and the size and distribution of the particles were measured using a NICOMP 380 (Entegris, dynamic light scattering).

[0096] 7. Particle shape analysis and elemental analysis (FE-SEM / EDS)

[0097] One or two drops of the polymerized latex were diluted and dispersed in 20 ml of water, and then one or two drops of the diluted solution were dropped onto a silicon wafer. The silicon wafer with the sample was dried under vacuum at room temperature for 2 to 3 hours, and then coated with platinum by sputtering for 90 seconds. The shape of the particles was examined at a resolution of 30,000 to 100,000 × 1280 at an accelerating voltage of 5 kV and a current of 10 μA.

[0098] 8. Analysis of particle structure (TEM / EDS)

[0099] A drop of latex was placed onto a plasma-treated grid for transmission electron microscopy (TEM) and dried at room temperature. The structure of the dried sample was analyzed using a TEM / EDS (FEI, TECNAI TF20) accelerating voltage of 200 kV.

[0100] 9. Methods for preparing electrode paste

[0101] A total of 100g of 96g NCM 622 (LG Chem), 2g Ketjen Black (EC-600JD available from Nouryon), and 2g binder were added to a Henschel mixer and mixed for 4 minutes. After mixing, the composition was added to a HAAKE rheology mixer (model name) and shear force was applied to achieve a tight bond through fibrillation, thereby obtaining... Figure 1 The electrode paste shown.

[0102] 10. Combined with strength screening method

[0103] The paste prepared according to the method for preparing electrode paste was added to a sieving machine (Haver & Boecker), which consisted of a cover, sieve 1 (aperture size: 6.3 mm, wire diameter: 1.8 mm), sieve 2 (aperture size: 4.75 mm, wire diameter: 1.6 mm), and a fan, and was sieved for 1 minute at an amplitude of 1. The weights of the particles graded by sieving are shown in Table 2.

[0104] [Example 1]

[0105] A PTFE aqueous dispersion with an average particle size of 0.21 μm, a solids content concentration of 30%, and a standard specific gravity (SSG) of 2.16 to 2.22 was prepared. Subsequently, 2448.0 g of the PTFE dispersion and 48.96 g of a 90% aqueous solution of polyethylene glycol trimethyl nonyl ether (TMN100X, available from Dow) (the molecular weight of the hydrophilic ethylene glycol repeating unit was mainly 384 g / mol) were added to a 4 L reactor and stirred at 350 rpm while being heated to 75 °C under nitrogen bubbling.

[0106] After the temperature reaches 75°C, the nitrogen bubbling is stopped, and after 15 minutes, a monomer mixture solution consisting of 36.72 g methyl methacrylate (MMA), 91.8 g methacrylic acid (MAA), 55.08 g butyl acrylate (nBA) and 0.40 g n-octyl mercaptan is added dropwise to the reactor.

[0107] Fifteen minutes after adding the monomer mixture, an aqueous solution of 68.4 g distilled water and 0.18 g ammonium persulfate was added dropwise to the reactor over approximately 10 minutes. The polymerization reaction proceeded for 3 hours from the end of the ammonium persulfate addition, followed by cooling to 30°C to obtain an emulsion.

[0108] The weight ratios of the emulsions are shown in Table 1.

[0109] Furthermore, according to method 9 for preparing electrode paste and method 10 for bonding strength sieving, an electrode paste containing an emulsion as a binder was prepared, and the bonding strength was measured by sieving. The results are shown in Table 2.

[0110] [Example 2]

[0111] The process was carried out in the same manner as in Example 1, except that the weights were changed to 73.44 g methyl methacrylate (MMA), 55.08 g methacrylic acid, 55.08 g butyl acrylate (nBA), 0.29 g n-octyl mercaptan, and 0.92 g ammonium persulfate.

[0112] [Example 3]

[0113] The process was carried out in the same manner as in Example 1, except that the weights were changed to 1836.0 g PTFE dispersion, 36.72 g 90% aqueous solution of polyethylene glycol trimethyl nonyl ether (TMN100X available from Dow) (the molecular weight of the hydrophilic ethylene glycol repeating unit is mainly 384 g / mol), 428.4 g additional water, 73.44 g methyl methacrylate (MMA), 183.6 g methacrylic acid, 110.16 g butyl acrylate (nBA), 0.81 g n-octyl mercaptan and 0.37 g ammonium persulfate.

[0114] [Example 4]

[0115] The process was carried out in the same manner as in Example 3, except that the weights were changed to 146.88 g methyl methacrylate (MMA), 110.16 g methacrylic acid, 110.16 g butyl acrylate (nBA), 0.59 g n-octyl mercaptan and 1.84 g ammonium persulfate.

[0116] [Example 5]

[0117] The process was carried out in the same manner as in Example 1, except that the weights were changed to 1224.0 g PTFE dispersion, 24.48 g 90% aqueous solution of polyethylene glycol trimethyl nonyl ether (TMN100X available from Dow) (the molecular weight of the hydrophilic ethylene glycol repeating unit is mainly 384 g / mol), 856.8 g additional water, 110.16 g methyl methacrylate (MMA), 275.40 g methacrylic acid, 165.24 g butyl acrylate (nBA), 1.21 g n-octyl mercaptan and 0.55 g ammonium persulfate.

[0118] [Example 6]

[0119] The process was carried out in the same manner as in Example 5, except that the weights were changed to 220.32 g methyl methacrylate (MMA), 165.24 g methacrylic acid, 165.24 g butyl acrylate (nBA), 0.88 g n-octyl mercaptan, and 2.75 g ammonium persulfate.

[0120] [Comparative Example 1]

[0121] The process was carried out in the same manner as in Example 1, except that the weights were changed to 146.88g methyl methacrylate (MMA), 0g methacrylic acid, 36.72g butyl acrylate (nBA), 0.26g n-octyl mercaptan and 0.92g ammonium persulfate.

[0122] [Comparative Example 2]

[0123] The process was carried out in the same manner as in Comparative Example 1, except that the weights were changed to 137.7 g of methyl methacrylate (MMA) and 45.9 g of methyl acrylate (MA) instead of butyl acrylate (nBA).

[0124] [Comparative Example 3]

[0125] The process was carried out in the same manner as in Example 3, except that the weights were changed to 293.76 g methyl methacrylate (MMA), 0 g methacrylic acid, 73.44 g butyl acrylate (nBA), 0.51 g n-octyl mercaptan and 1.84 g ammonium persulfate.

[0126] [Comparative Example 4]

[0127] The process was carried out in the same manner as in Comparative Example 3, except that the weights were changed to 275.4 g of methyl methacrylate (MMA) and 91.80 g of methyl acrylate (MA) instead of butyl acrylate (nBA).

[0128] [Comparative Example 5]

[0129] The process was carried out in the same manner as in Example 5, except that the weights were changed to 440.64 g methyl methacrylate (MMA), 0 g methacrylic acid, 110.16 g butyl acrylate (nBA), 0.77 g n-octyl mercaptan and 2.75 g ammonium persulfate.

[0130] [Comparative Example 6]

[0131] The process was carried out in the same manner as in Comparative Example 5, except that the weights were changed to 413.1 g of methyl methacrylate (MMA) and 137.7 g of methyl acrylate (MA) instead of butyl acrylate (nBA).

[0132] [Table 1]

[0133]

[0134] [Table 2]

[0135]

[0136] As can be seen from the analysis results, when core-shell particles containing methyl methacrylate (MMA), methacrylic acid (MAA) and butyl acrylate (nBA) as described in Examples 1 and 2 of this disclosure are used as binders, the weight percentage of coarse particles measured in sieve 1 is as high as 90% or more, and it is determined that the particles as binders have excellent bonding strength with electrode active materials, etc.

[0137] Furthermore, as shown in Examples 3 to 6, even when the amount of PTFE used is small, the weight percentage of coarse particles remains at 90% or more, and excellent bonding strength with electrode active materials, etc., is maintained.

[0138] However, when methyl methacrylate and butyl acrylate or methyl methacrylate and methyl acrylate are used in combination, as in Comparative Examples 1 to 6, the weight percentage of coarse particles is as low as 34%, and the weight percentage of fine particles is as high as 50% or more, and it is determined that the particles as binders have weak bonding strength with electrode active materials, etc.

[0139] Preferred exemplary embodiments of the present invention have been described above; however, various modifications and equivalents may be used in the present invention, and it is apparent that the above embodiments can be suitably modified and applied in the same manner. Therefore, the above description does not limit the scope of the invention as defined by the appended claims.

Claims

1. A core-shell particle comprising a perfluorinated resin core comprising a perfluoropolymer and a resin shell layer comprising an acryl group-based polymer, wherein the core-shell particle is manufactured by emulsion polymerization of an acryl group-based monomer to the perfluorinated resin core using, as an emulsifier, a polyethylene glycol ether having a C8 or higher alkyl group substituted with one or more alkyl groups of the following Chemical Formula 1, and the acryl group-based monomer comprises: (a) methyl methacrylate; (b) methacrylic acid or acrylic acid; and (c) a C2 to C6 alkyl (meth)acrylate: [Chemical Formula 1] R-(-O-C2H4-) n -OH wherein R is a C8 or higher alkyl group substituted with one or more alkyl groups, and n is an integer of 5 to 15, wherein Chemical Formula 1 is an emulsifier of the following Chemical Formula 2: [Chemical Formula 2] 。 2. The core-shell particle according to claim 1, wherein the perfluoropolymer is polytetrafluoroethylene.

3. The core-shell particle according to claim 1, wherein the core-shell particle comprises the perfluoropolymer and the acryl group-based polymer in a weight ratio of 98:2 to 30:

70.

4. The core-shell particle according to claim 3, wherein the core-shell particle comprises the perfluoropolymer and the acryl group-based polymer in a weight ratio of 80:20 to 40:

60.

5. The core-shell particle according to claim 1, wherein the methyl methacrylate is contained in the acryl group-based monomer in an amount of 20 to 40% by weight.

6. The core-shell particle according to claim 1, wherein the methacrylic acid or the acrylic acid is contained in the acryl group-based monomer in an amount of 30 to 50% by weight.

7. The core-shell particle according to claim 1, wherein the C2 to C6 alkyl (meth)acrylate is contained in the acryl group-based monomer in an amount of 20 to 40% by weight.

8. A composition comprising the core-shell particle according to claim 1 and an electrode active material.

9. An electrode manufactured from the composition according to claim 8.

10. A battery comprising the core-shell particle according to claim 1 as a binder.

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