Hydrogenated nitrile rubber

Abstract

The present invention provides a hydrogenated nitrile rubber that exhibits excellent dispersibility and stability of conductive material dispersions, excellent viscosity stability of cathode slurries, excellent peel strength and warping characteristics of electrodes, and excellent capacitance, resistance, and cycle characteristics of electrochemical elements. [Solution] The hydrogenated nitrile rubber of the present invention contains acrylonitrile polymerization units and 1,3-butadiene polymerization units, wherein the proportion of acrylonitrile polymerization units is 28% by mass or more and 40% by mass or less, the total proportion of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization units is 7% by mass or more, the weight-average molecular weight (Mw) is in the range of 10,000 to 2,500,000, it contains an antioxidant, the polymer pH is 4.5 to 6, the iodine value is 100 mg / 100 mg or less, and the bulk density is 0.7 g / cm³. 3 That's all.

Description

[Technical Field]

[0001] The present invention relates to hydrogenated nitrile rubber, a method for producing the same, a bale of hydrogenated nitrile rubber, and a positive electrode material, a positive electrode binder, a conductive material dispersion, a positive electrode slurry, a positive electrode, and an electrochemical element using hydrogenated nitrile rubber. [Background technology]

[0002] Electrochemical elements such as lithium-ion secondary batteries, lithium-ion capacitors, and electric double-layer capacitors are small, lightweight, have high energy density, and can be repeatedly charged and discharged, making them suitable for a wide range of applications. Therefore, in recent years, improvements to battery components such as electrodes have been considered to further enhance the performance of electrochemical elements.

[0003] Here, the electrodes used in electrochemical elements typically comprise a current collector and an electrode composite layer formed on the current collector. This electrode composite layer is formed, for example, by applying a slurry containing an electrode active material, a conductive material, and a binder onto the current collector and then drying the applied slurry.

[0004] Therefore, in recent years, attempts have been made to improve the binders used in forming electrode composite layers in order to achieve further performance improvements in electrochemical elements. For example, the use of hydrogenated nitrile rubber as a binder is being investigated.

[0005] For example, Patent Document 1 (WO2013 / 129658) describes a heavy electrode having a nitrile group as a positive electrode active material. combinationA lithium-ion secondary battery with excellent cycle characteristics is disclosed, comprising a first polymer containing a polymerization unit having a hydrophilic group, a (meth)acrylic acid ester polymerization unit, and a linear alkylene polymerization unit having 4 or more carbon atoms, and a fluorine-containing polymer as a binder component. Specifically, the first polymer is obtained by (1) adding deionized water, sodium alkylbenzene sulfonate, acrylonitrile, butyl acrylate, methacrylic acid, 1,3-butadiene, and ammonium persulfate to an autoclave with a stirrer and carrying out emulsion polymerization at 40°C until the polymerization conversion rate reaches 85%, (2) adding palladium acetate to the obtained polymerization solution and carrying out a hydrogenation reaction twice at a hydrogen pressure of 3 MPa and 50°C for 6 hours, and then (3) coagulating with methanol, and (4) containing 20% ​​by mass of acrylonitrile polymerization units, 45% by mass of conjugated diene-derived polymerization units, 30% by mass of butyl acrylate polymerization units, and 5% by mass of methacrylic acid polymerization units, wherein the conjugated diene-derived polymerization units are formed from 38.8% by mass of hydrogenated linear alkylene structural units having 4 or more carbon atoms, 2.1% by mass of unhydrogenated butadiene polymerization units, and 4.1% by mass of 1,2-addition polymerization units, and obtaining hydrogenated NBR with an iodine value of 8 mg / 100 mg. In recent years, there has been a growing demand for further improvements in the long-term storage properties of cathode binders, the dispersibility and stability of conductive material dispersions, and the viscosity stability of cathode slurries. Additionally, there is a growing desire for improvements in the flexibility of manufactured electrodes, the capacitance characteristics, resistance characteristics, and high-temperature storage characteristics of electrochemical elements.

[0006] Patent document 2 (WO2022 / 163321) discloses a non-aqueous electrochemical element that contains polymer A, which includes nitrile group-containing monomer units and alkylene structural units, and a specific ester solvent and a non-halogenated carbonate solvent, exhibiting excellent suppression of DC resistance increase at low temperatures and high-temperature storage properties. . IngredientsSpecifically, (1) an aqueous dispersion of polymer A precursor (particulate polymer) is obtained by charging an ion-exchanged water reactor with monomers such as acrylonitrile and 1,3-butadiene, sodium dodecylbenzenesulfonate as an emulsifier, and t-dodecyl mercaptan as a chain transfer agent, and then continuously adding cumene hydroperoxide as a polymerization initiator, a reducing agent, and a chelating agent to perform emulsion polymerization at 10°C until the polymerization conversion rate reaches 80%, and then (2) 1% acetic acid as a hydrogenation catalyst. (3) A palladium acetone solution is added, and a hydrogenation reaction is carried out at a hydrogen pressure of 3 MPa and a temperature of 50°C for 6 hours. (4) NMP is added as an organic solvent to the aqueous dispersion after the hydrogenation reaction, and all water is removed under reduced pressure. (5) An 8% NMP solution of polymer A, consisting of 35% by mass of acrylonitrile, 65% by mass of butadiene, 18% by mass of hydrogenated 1,2-butadiene polymerization units, and a weight-average molecular weight of 150,000, is obtained. (6) Multiwall carbon nanotubes are added thereto to obtain a conductive material dispersion. On the other hand, there is a need to further improve the long-term storage properties of the positive electrode binder, the dispersibility and stability of the conductive material dispersion, and the viscosity stability of the positive electrode slurry, as well as to improve the peel strength and warping characteristics of the electrode, the resistance characteristics of the electrochemical element, the cycle characteristics, and the storage characteristics at high temperatures.

[0007] Patent Document 3 (WO2019 / 181869) discloses a conductive material dispersion with excellent dispersibility of carbon nanotubes, containing a binder containing a polymer containing carbon nanotubes, aromatic vinyl monomer units, and linear alkylene structural units having 4 or more carbon atoms, and a dispersion medium. Specifically, the polymer is prepared by (1) charging an ion-exchanged water reactor with an aqueous solution of sodium dodecylbenzenesulfonate as an emulsifier, styrene, acrylonitrile, methacrylic acid, 1,3-butadiene, and t-dodecyl mercaptan (2 parts) as a molecular weight modifier, and adding cumene hydroperoxide as a polymerization initiator while maintaining the temperature at 10°C, and emulsion polymerization until the conversion rate reaches 85% to obtain an aqueous dispersion of the precursor (particulate polymer). (2) Palladium acetate is added to the obtained aqueous dispersion of the precursor, and a hydrogenation reaction is carried out at a hydrogen pressure of 3 MPa and 50°C for 6 hours to produce a polymer with a styrene content of 33-48% by mass, acrylonitrile content of 10-21% by mass, conjugated diene (unhydrogenated) content of 4-6.5% by mass, linear alkylene structural units with 4 or more carbon atoms (conjugated diene hydrogenated content) of 22-43% by mass, a weight-average molecular weight (Mw) of 50,000 and an iodine value of 15-38. However, further improvements are desired, such as improved long-term storage properties of the cathode binder and stability of the conductive material dispersion, as well as improvements in electrode peel strength and warping characteristics, capacitance characteristics and cycle characteristics in electrochemical elements, and resistance increase during high-temperature storage.

[0008] Patent Document 4 (WO2023 / 162835) discloses an electrochemical device composition containing a polymer that includes a nitrile group-containing monomer unit and a conjugated diene monomer unit and / or an alkylene structural unit, and has a functional group such as a carboxyl group, a trimethoxysilyl group, or a hydroxyl group at at least one end. The composition is excellent in the flexibility of the electrode and the suppression of crack generation in the electrode active material. Specifically, as the polymer, (1) ion-exchanged water, a monomer component of 33 parts of acrylonitrile and 67 parts of 1,3-butadiene, potassium oleate as an emulsifier, and tert-dodecyl mercaptan (0.3 parts) as a molecular weight regulator are charged into a reactor, and emulsion polymerization is carried out at 5°C until the polymerization conversion rate reaches 89% in the presence of potassium persulfate as a polymerization initiator. (2) After adding dibutylhydroxytoluene (BHT) as an antioxidant to the obtained polymerization solution, (3) a 25% by mass calcium chloride aqueous solution is added while stirring to coagulate the polymer. After washing with ion-exchanged water 50 times the amount of the polymer, it is dried under reduced pressure at 90°C to obtain a precursor (nitrile rubber) with a weight average molecular weight of 210,000. Subsequently, (4) the obtained precursor is dissolved in monochlorobenzene and Grubbs catalyst (bis(bis(dichloride)) (tricyclohexylphosphine)benzylidene ruthenium) is added, and a metathesis reaction is carried out at 80°C and a stirring speed of 600 rpm. Then, (5) Wilkinson's catalyst and triphenylphosphine are added, and a hydrogenation reaction is carried out at 138°C and a hydrogen pressure of 8.4 MPa. (6) For adjusting the divalent or higher metal ion concentration and removing the residual chain transfer agent, after performing activated carbon treatment, it is filtered and dried. (7) A hydrogenated nitrile rubber with a weight average molecular weight of 48,000, an iodine value of 13, and a divalent or higher metal ion concentration of 200 ppm or less is obtained. However, further improvement in the capacity characteristics, cycle characteristics, and storage characteristics at high temperatures of the electrochemical device, as well as reduction of the ash content in the hydrogenated nitrile rubber, is desired.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

[0010] The present invention has been made in view of the above circumstances, and aims to provide hydrogenated nitrile rubber and a method for producing the same, a bale of hydrogenated nitrile rubber formed from hydrogenated nitrile rubber, and a positive electrode material, a positive electrode binder, a conductive material dispersion, a positive electrode slurry, a positive electrode, and an electrochemical element using hydrogenated nitrile rubber. [Means for solving the problem]

[0011] In view of the above problems, the present inventors have diligently conducted research and have found a material comprising acrylonitrile polymerization units and 1,3-butadiene polymerization units, The aforementioned We have found that a hydrogenated nitrile rubber, in which the proportion of acrylonitrile polymerization units and the proportion of 1,2-bonding units in the 1,3-butadiene polymerization units are within a specific range, has a specific weight-average molecular weight (Mw) and polymer pH, contains an antioxidant, and has a low iodine value and high bulk density, can improve the dispersibility and stability of conductive material dispersions, improve the viscosity stability of cathode slurries, enhance the peel strength and warp characteristics of electrodes, and significantly improve the capacitance characteristics, resistance characteristics, and cycle characteristics of electrochemical elements in the manufacture of electrochemical elements.

[0012] The inventors have found that by setting the proportion of acrylonitrile polymerization units in hydrogenated nitrile rubber and the proportion of 1,2-bonding units in 1,3-butadiene polymerization units within a specific range, the dispersibility of the conductive material dispersion can be improved, the flexibility and warp characteristics of the electrodes can be enhanced, and the capacitance, resistance, and cycle characteristics of the electrochemical element can be improved, resulting in a high degree of balance between these properties. The inventors have also found that the proportion of 1,2-bonding units in the 1,3-butadiene polymerization units of hydrogenated nitrile rubber can be controlled by selecting the type of polymerization initiator, polymerization temperature, and polymerization conversion rate of the nitrile rubber.

[0013] The inventors have found that by setting the weight-average molecular weight (Mw) of hydrogenated nitrile rubber within a specific range, the dispersibility of the conductive material dispersion, the peel strength of the electrode, and the resistance characteristics of the electrochemical element can be improved. of We have found a way to elevate these characteristics to a high degree and achieve a high level of balance. Ta.

[0014] The inventors have found that by including an antioxidant in hydrogenated nitrile rubber and specifying the polymer pH, the stability of the conductive material dispersion is enhanced, the viscosity stability of the cathode slurry is improved, and the capacitance and resistance characteristics of the electrochemical element can be significantly improved. The inventors have also found that adjusting the polymer pH of hydrogenated nitrile rubber at the stage of emulsion polymerization after emulsion polymerization of nitrile rubber, when an antioxidant is added, is preferable because it facilitates the removal of impurities originating from the buffer used, etc., and the adjusted pH is maintained in the hydrogenated nitrile rubber after the hydrogenation reaction.

[0015] The inventors have discovered that by reducing the iodine value of hydrogenated nitrile rubber and increasing its bulk density, the stability of conductive material dispersions and the cycle characteristics of electrode chemical elements can be significantly improved. They found that increasing the bulk density of hydrogenated nitrile rubber can be achieved by baling the crumb-shaped hydrogenated nitrile rubber under high pressure using a bailer, or by extruding the hydrogenated nitrile rubber into a sheet using a screw-type twin-screw extruder and then laminating the sheet-shaped hydrogenated nitrile rubber. Furthermore, they found that a hydrogenated nitrile rubber bale with an overwhelmingly high bulk density (low oxygen content) can be produced by extruding dried sheet-shaped hydrogenated nitrile rubber from which the air contained within has been removed using a screw-type twin-screw extruder equipped with a reduced-pressure drying section, and then laminating the sheet-shaped dried rubber.

[0016] The inventors further investigated the following aspects of hydrogenated nitrile rubber: the proportion of acrylonitrile polymerization units, the proportion of 1,2- units in 1,3-butadiene polymerization units, the content of the antioxidant, the weight-average molecular weight (Mw), the ratio of Z-average molecular weight (Mz) to weight-average molecular weight (Mw) (Mz / Mw), the polymer pH, the water content, the ash content, and the proportions of sodium and potassium in the ash, the proportions of calcium and sulfur, the proportions of rhodium and ruthenium, the proportion of phosphorus, and the sum of sodium and potassium and the sum of calcium and sulfur. mass Ratio of calcium to chlorine mass Ratio of calcium to sulfur mass Ratio of sulfur to chlorine mass By specifying ratios and other parameters, we found that the dispersibility and stability of conductive material dispersions, the viscosity stability of cathode slurries, the peel strength and warpage characteristics of electrodes, and the capacitance, resistance, and cycle characteristics of electrochemical elements can be further improved.

[0017] Based on these findings, the inventors have completed the present invention.

[0018] Thus, according to the present invention, the polymer comprises acrylonitrile polymerization units and 1,3-butadiene polymerization units, wherein the proportion of the acrylonitrile polymerization units is 28% by mass or more and 40% by mass or less, and the total proportion of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization units is 7% by mass or more. , heavy The weight-average molecular weight (Mw) is in the range of 10,000 to 2,500,000, it contains an antioxidant, the polymer pH is between 4.5 and 6, the iodine value is 100 mg / 100 mg or less, and the bulk density is 0.7 g / cm³. 3 Hydrogenated nitrile rubber as described above is provided.

[0019] In the hydrogenated nitrile rubber of the present invention, it is preferable that the total ratio of acrylonitrile polymerization units and 1,3-butadiene polymerization units is 70 to 100% by mass.

[0020] In the hydrogenated nitrile rubber of the present invention, the bulk density is 0.8 cm³. 3 It is preferable that the amount is 1 / g or more.

[0021] In the hydrogenated nitrile rubber of the present invention, the content of the anti-aging agent is preferably in the range of 0.001 to 2% by mass.

[0022] In the hydrogenated nitrile rubber of the present invention, the polymer pH is preferably 4.5 or higher and 5.5 or lower.

[0023] In the hydrogenated nitrile rubber of the present invention, it is preferable that the iodine value is 50 mg / 100 mg or less.

[0024] In the hydrogenated nitrile rubber of the present invention, it is preferable that the weight-average molecular weight (Mw) is 30,000 or more and 1,000,000 or less.

[0025] In the hydrogenated nitrile rubber of the present invention, it is preferable that the ash content is 0.7% by mass or less.

[0026] In the hydrogenated nitrile rubber of the present invention, it is preferable that the ash content is 0.01% by mass or more.

[0027] In the hydrogenated nitrile rubber of the present invention, The aforementioned It is preferable that the total amount of calcium (Ca) and sulfur (S) in the ash (Ca+S) is 30% by mass or more.

[0028] In the hydrogenated nitrile rubber of the present invention, The aforementioned It is preferable that the total amount of sodium (Na) and potassium (K) in the ash (Na+K) is 20% by mass or less.

[0029] In the hydrogenated nitrile rubber of the present invention, The aforementioned The difference between calcium content (Ca) and chlorine content (Cl) in ash mass It is preferable that the ratio (Ca / Cl) is 1 or greater.

[0030] In the hydrogenated nitrile rubber of the present invention, The aforementioned The sulfur content (S) and chlorine content (Cl) in the ash mass It is preferable that the ratio (S / Cl) is 1 or greater.

[0031] In the hydrogenated nitrile rubber of the present invention, The aforementioned The relationship between calcium content (Ca) and sulfur content (S) in ash mass The ratio (Ca / S) is preferably 3.5 or less.

[0032] In the hydrogenated nitrile rubber of the present invention, The aforementioned The sum of sodium (Na) and potassium (K) content in the ash (Na+K) and the sum of calcium (Ca) and sulfur (S) content (Ca+S) mass It is preferable that the ratio ((Na+K) / (Ca+S)) is 0.5 or less.

[0033] In the hydrogenated nitrile rubber of the present invention, The aforementionedIt is preferable that the content (M) of the metal used in the hydrogenation catalyst in the ash is 1% by mass or less.

[0034] In the hydrogenated nitrile rubber of the present invention, The aforementioned The sum of rhodium (Rh) and ruthenium (Ru) content in the ash. amount The (Rh+Ru) ratio is preferably 1% by mass or less.

[0035] In the hydrogenated nitrile rubber of the present invention, The aforementioned It is preferable that the phosphorus content (P) ratio in the ash is 10% by mass or less.

[0036] In the hydrogenated nitrile rubber of the present invention, it is preferable that the ratio of the Z-average molecular weight (Mz) to the weight-average molecular weight (Mw) (Mz / Mw) is 1.5 or higher.

[0037] In the hydrogenated nitrile rubber of the present invention, the weight-average molecular weight measured with N-methylpyrrolidone (NMP) (NMP-Mw) and the weight-average molecular weight measured with tetrahydrofuran (THF) (THF-Mw) are such that NMP-Mw ≥ THF-M w It is preferable that they be in a relationship.

[0038] In the hydrogenated nitrile rubber of the present invention, it is preferable that the water content is less than 1% by mass.

[0039] In the hydrogenated nitrile rubber of the present invention, it is preferable that the polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene and coagulation with calcium chloride is hydrogenated.

[0040] In the hydrogenated nitrile rubber of the present invention, it is preferable that the polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene using an alkali metal salt as a polymerization auxiliary material is hydrogenated.

[0041] In the hydrogenated nitrile rubber of the present invention, it is preferable that a polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene is hydrogenated using sulfate and / or sulfonate as polymerization auxiliary materials.

[0042] In the hydrogenated nitrile rubber of the present invention, it is preferable that at least one salt compound selected from the group consisting of alkali metal salts, sulfates, and sulfonates is used as a polymerization auxiliary material, and that the polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene and coagulation with calcium chloride is hydrogenated.

[0043] The present invention also includes an emulsion polymerization step of emulsion polymerization of monomer components containing acrylonitrile and 1,3-butadiene to obtain an emulsion polymerization solution, The process involves adding an antioxidant to the resulting emulsion polymerization solution, A coagulation step in which an emulsion polymerization solution to which an antioxidant is added is brought into contact with a coagulation solution to produce a hydrated crumb, The resulting water-containing crumb is washed, dehydrated, and dried in a washing, dehydration, and drying process. The dried polymer is dissolved in an organic solution. medium A hydrogenation step in which the substance is dissolved and a hydrogenation reaction is carried out, A hydrogenated polymer dehydration and drying process is performed in which the reaction solution after the hydrogenation reaction is solidified to produce a water-containing crumb, which is then dehydrated and dried using a screw-type twin-screw extruder to extrude the dried rubber. Including the above A method for manufacturing hydrogenated nitrile rubber is provided.

[0044] The present invention also provides a hydrogenated nitrile rubber bale obtained by bailing the above-mentioned hydrogenated nitrile rubber.

[0045] The present invention also provides a positive electrode material comprising the above-mentioned hydrogenated nitrile rubber.

[0046] The present invention also provides a positive electrode binder obtained by dissolving the above-mentioned hydrogenated nitrile rubber in N-methylpyrrolidone (NMP).

[0047] The present invention also provides a conductive material dispersion liquid obtained by dissolving or dispersing the above-mentioned hydrogenated nitrile rubber and conductive material in N-methylpyrrolidone (NMP).

[0048] The present invention also provides a slurry for a positive electrode obtained by dissolving or dispersing a positive electrode active material, a conductive material, and the above-mentioned hydrogenated nitrile rubber in N-methylpyrrolidone (NMP).

[0049] The present invention also provides a positive electrode comprising the above-mentioned hydrogenated nitrile rubber.

[0050] The present invention further provides an electrochemical element comprising the above-mentioned hydrogenated nitrile rubber. [Effects of the Invention]

[0051] The present invention provides hydrogenated nitrile rubber and a method for producing the same, a bale of hydrogenated nitrile rubber, and a positive electrode material, a positive electrode binder, a conductive material dispersion, a positive electrode slurry, a positive electrode, and an electrochemical element using hydrogenated nitrile rubber. [Brief explanation of the drawing]

[0052] [Figure 1] This figure shows an example of a nitrile rubber manufacturing system according to an embodiment of the present invention. [Figure 2] This figure shows an example of the upstream section of a hydrogenated nitrile rubber manufacturing system according to an embodiment of the present invention. [Figure 3] This figure shows an example of the downstream section of a hydrogenated nitrile rubber manufacturing system in an embodiment of the present invention. [Modes for carrying out the invention]

[0053] Embodiments of the present invention will be described in detail below.

[0054] <Hydrogenated nitrile rubber> The hydrogenated nitrile rubber of the present invention contains acrylonitrile polymerization units and 1,3-butadiene polymerization units, wherein the proportion of acrylonitrile polymerization units is 28% by mass or more and 40% by mass or less, the total proportion of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization units is 7% by mass or more, the weight-average molecular weight (Mw) is in the range of 10,000 to 2,500,000, it contains an antioxidant, the polymer pH is 4.5 to 6, the iodine value is 100 mg / 100 mg or less, and the bulk density is 0.7 g / cm³. 3 The above is the characteristic feature.

[0055] (Repeating unit) The hydrogenated nitrile rubber of the present invention comprises acrylonitrile polymerization units and 1,3-butadiene polymerization units, wherein the 1,3-butadiene polymerization units consist of 1,2-bonding units, 1,4-bonding units, and their hydride units. Such hydrogenated nitrile rubber is a component that can function as a binder in the electrode composite layer formed in an electrochemical element, holding electrode active materials and the like from the current collector without detaching them. Furthermore, such hydrogenated nitrile rubber can also function as a dispersant in a conductive material dispersion containing a conductive material, capable of dispersing the conductive material.

[0056] The proportion of acrylonitrile polymerization units in the hydrogenated nitrile rubber of the present invention is 、2 The amount is in the range of 8% by mass or more, preferably 29% by mass or more, more preferably 30% by mass or more, and 40% by mass or less, preferably 39% by mass or less, and more preferably 38% by mass or less. When the acrylonitrile polymerization units in the hydrogenated nitrile rubber are in this range, it is preferable because it improves the dispersibility of the conductive material dispersion and enhances the cycle characteristics of the electrochemical element.

[0057] The proportion of 1,3-butadiene polymerization units in the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 40% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more, or preferably 55% by mass or more, 60% by mass or more, 61% by mass or more, and 62% by mass or more in that order, and is usually in the range of 72% by mass or less, preferably 71% by mass or less, more preferably 70% by mass or less. The 1,3-butadiene polymerization units in the hydrogenated nitrile rubber refer to the total number of unhydrogenated and hydrogenated units of 1,3-butadiene polymerization units, that is, the total number of 1,2-bonding units, 1,4-bonding units and their hydride units.

[0058] The total ratio of acrylonitrile polymerization units and 1,3-butadiene polymerization units in the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually in the range of 70 to 100% by mass, preferably 80 to 100% by mass, more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and most preferably 97 to 100% by mass.

[0059] The total ratio of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization unit of the hydrogenated nitrile rubber of the present invention is 7% by mass or more, preferably 7.5% by mass or more, more preferably 8% by mass or more, or in the order of 8.5% by mass or more, 9% by mass or more, 9.5% by mass or more, 10% by mass or more, 10.5% by mass or more, 11% by mass or more, 11.5% by mass or more, 12% by mass or more, 12.5% ​​by mass or more, and 13% by mass or more. When the total ratio of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization unit of the hydrogenated nitrile rubber is within this range, it is preferable to enhance the electrode warpage characteristics and the capacitance characteristics of the electrochemical element.

[0060] The upper limit of the total ratio of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization unit of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 50% by mass or less, preferably 45% by mass or less, more preferably 40% by mass or less, or preferably in the order of 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 19% by mass or less, 18% by mass or less, 17% by mass or less, 16% by mass or less, and 15% by mass or less, which can increase the flexibility of the manufactured electrode. The ratio of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization unit is not particularly limited and can be appropriately adjusted based on the iodine value of the hydrogenated nitrile rubber.

[0061] The hydrogenated nitrile rubber of the present invention may contain, as necessary, other repeating units in addition to the acrylonitrile polymerization units and 1,3-butadiene polymerization units described above. There are no particular limitations on the other repeating units, but for example, polar group-containing monomer units are preferably used.

[0062] There are no particular limitations on the polar group of the polar group-containing monomer unit, but examples include epoxy groups, acetoacetoxyalkyl groups, diester dicarboxylic acid groups, and acidic groups, with acidic groups being preferred.

[0063] Examples of epoxy group-containing monomers that can form epoxy group-containing monomer units include glycidyl methacrylate and glycidyl acrylate, with glycidyl methacrylate being preferred. Examples of acetoacetoxyalkyl group-containing monomers include acetoacetoxyethyl methacrylate. Examples of diester dicarboxylic acid group-containing monomers include dibutyl maleate.

[0064] Examples of acidic group-containing monomers that can form acidic group-containing monomer units include carboxylic acid group-containing monomers, sulfonic acid group-containing monomers, and phosphate group-containing monomers, among which carboxylic acid group-containing monomers are preferred.

[0065] Examples of monomers containing a carboxylic acid group include monocarboxylic acids, dicarboxylic acids and their acid anhydrides, with monocarboxylic acids being preferred. Examples of monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, monobutyl maleate, and monododecyl maleate, with methacrylic acid, acrylic acid, and monobutyl maleate being preferred, and methacrylic acid being more preferred. Examples of dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, and fluoromaleic acid.

[0066] Examples of monomers containing sulfonic acid groups include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth)allyl sulfonic acid, styrene sulfonic acid, ethyl 2-(meth)acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and 3-alyloxy-2-hydroxypropanesulfonic acid. Examples of monomers containing phosphate groups include 2-(meth)acryloyloxyethyl phosphate, methyl-2-(meth)acryloyloxyethyl phosphate, and ethyl-(meth)acryloyloxyethyl phosphate.

[0067] These other repeating units can be used individually or in combination of two or more types. There are no particular limitations on the content of these other repeating units in the hydrogenated nitrile rubber, but it is usually 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and most preferably 3% by mass or less.

[0068] (Anti-aging agent) The hydrogenated nitrile rubber of the present invention is characterized by containing an anti-aging agent. Including an anti-aging agent in the hydrogenated nitrile rubber is preferable because it greatly enhances the stability of the conductive material dispersion and the peel strength of the electrodes in the manufacture of electrochemical elements.

[0069] There are no particular limitations on the type of antioxidant that can be included, but examples include amine-based antioxidants and phenol-based antioxidants, with phenol-based antioxidants being preferred. There are no particular limitations on the type of phenol-based antioxidant, but hindered phenol-based antioxidants are particularly preferred, as they can improve the stability of the conductive material dispersion and enhance the electrode peel strength.

[0070] Examples of hindered phenol-based antioxidants include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-pentenyl-4-methylphenol, 2,2-methylenebis(4-methyl-6-t-butylphenol), 2,4-bis(octylthiomethyl)-6-methylphenol, 2,6-di-t-butyl-α-dimethylamino-p-cresol, and 3-(4-hydroxy-3,5 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate butyl, 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate hexyl, 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate octyl, 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate decyl, 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate dodecyl, 3-(4-hydroxy-3,5-di-t-butylphenyl)propionate butyl Examples include octadecyl 3-(4-hydroxy-3,5-diisopropylphenyl)propionate, heptyl 3-(4-hydroxy-3,5-diisopropylphenyl)propionate, octyl 3-(4-hydroxy-3,5-diisopropylphenyl)propionate, dodecyl 3-(4-hydroxy-3,5-diisopropylphenyl)propionate, octadecyl 3-(4-hydroxy-3,5-diisopropylphenyl)propionate, 4,4'-methylenebis(2,6-dibutylphenol), 2,6-di-t-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine-2-ylamino)phenol, and preferably 2,6-di-t-butyl-4-methylphenol (dibutylhydroxytoluene = BHT), 2,2-methylenebis(4-methyl-6-t-butylphenol), and 2,4-bis(octylthiomethyl)-6-methylphenol, with BHT being the most preferred.

[0071] Examples of phenolic antioxidants other than hindered phenolic antioxidants include styrene-phenols such as styrene-phenols, butylhydroxyanisole, mono(or di, or tri)(α-methylbenzyl)phenol, 2,2'-methylene-bis(4-methyl-6-t-butylphenol), alkylated bisphenols, 2,4-bis[(octylthio)methyl]-6-methylphenol, 2,2'-thiobis-(4-methyl-6-t-butylphenol), and 4,4'-thiobis-(6-t-butyl-o-cresol), with styrene-phenols and 2,4-bis[(octylthio)methyl]-6-methylphenol being preferred.

[0072] These antioxidants can be used individually or in combination of two or more. The content of the antioxidant in the hydrogenated nitrile rubber is not particularly limited, but is usually in the range of 0.001 to 2% by mass, preferably 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass, even more preferably 0.1 to 0.5% by mass, and most preferably 0.1 to 0.3% by mass. If the content of the antioxidant in the hydrogenated nitrile rubber is excessively low, the stability of the dispersion with the conductive material and the peel strength of the electrode will be poor, and if it is excessively high, it will affect the cycle characteristics of the electrochemical element.

[0073] (characteristic) The hydrogenated nitrile rubber of the present invention contains the above-mentioned repeating units and an anti-aging agent, and has a specific iodine value, a specific bulk density, a specific polymer pH, and a specific weight-average molecular weight (Mw).

[0074] The iodine value of the hydrogenated nitrile rubber of the present invention is 100 mg / 100 mg or less, preferably 80 mg / 100 mg or less, more preferably 60 mg / 100 mg or less, and further preferably 50 mg / 100 mg or less, 40 mg / 100 mg or less, 30 mg / 100 mg or less, 20 mg / 100 mg or less, 10 mg / 100 mg or less in this order. The lower limit is usually 0.1 mg / 100 mg or more, preferably 0.5 mg / 100 mg or more, more preferably 1 mg / 100 mg or more, still more preferably 1.5 mg / 100 mg or more, and most preferably 2 mg / 100 mg or more. When the iodine value of the hydrogenated nitrile rubber is within this range, the stability of the conductive material dispersion, the flexibility of the electrode, and the cycle characteristics of the electrochemical device can be highly improved.

[0075] The bulk specific gravity of the hydrogenated nitrile rubber of the present invention is 0.7 g / cm 3 or more, preferably 0.73 g / cm 3 or more, more preferably 0.75 g / cm 3 or more, or 0.77 g / cm 3 or more, 0.8 g / cm 3 or more, 0.83 g / cm 3 or more, 0.85 g / cm 3 or more, 0.87 g / cm 3 or more, 0.9 g / cm 3 or more, 0.91 g / cm 3 or more, 0.92 g / cm 3 or more, 0.93 g / cm 3 or more, 0.94 g / cm 3 or more, 0.95 g / cm 3 or more in this order. When the bulk specific gravity of the hydrogenated nitrile rubber is within this range, the stability of the conductive material dispersion can be remarkably improved and it is suitable.

[0076] The polymer pH of the hydrogenated nitrile rubber of the present invention is in the range of 4.5 or higher, preferably 4.6 or higher, more preferably 4.7 or higher, even more preferably 4.8 or higher, particularly preferably 4.9 or higher, most preferably 5 or higher, and 6 or lower, preferably 5.9 or lower, more preferably 5.8 or lower, even more preferably 5.7 or lower, particularly preferably 5.6 or lower, and most preferably 5.5 or lower. When the pH of the hydrogenated nitrile rubber is in this range, the viscosity stability of the positive electrode slurry can be increased, and the capacitance and resistance characteristics of the electrochemical element can be improved.

[0077] The weight-average molecular weight (Mw) of the hydrogenated nitrile rubber of the present invention is 10,000 or more, preferably 30,000 or more, more preferably 50,000 or more, or preferably in the order of 70,000 or more, 100,000 or more, 130,000 or more, 150,000 or more, and 200,000 or more, and preferably 2,500,000 or less, preferably 2,000,000 or less, more preferably 1,500,000 or less, or preferably in the order of 1,000,000 or less, 750,000 or less, and 500,000 or less. When the Mw of the hydrogenated nitrile rubber is in this range, the dispersibility of conductive materials is significantly improved, the peel strength of the manufactured electrodes and the resistance characteristics of the electrochemical elements are enhanced, and these characteristics can be highly balanced.

[0078] In the hydrogenated nitrile rubber of the present invention, N-methylpyrrolidone (NMP) is dissolved medium The weight-average molecular weight (NMP-Mw) measured and tetrahydrofuran (THF) were dissolved. medium The weight-average molecular weight (THF-Mw) measured using this method. and However, when the relationship NMP-Mw ≥ THF-Mw holds, the dispersibility and stability of conductive material dispersions using NMP as a solvent can be greatly improved.

[0079] The weight-average molecular weight (NMP-Mw) of the hydrogenated nitrile rubber of the present invention was measured using N-methylpyrrolidone (NMP) as a solvent, and also measured using tetrahydrofuran (THF) as a solvent. weightThe ratio (NMP-Mw / THF-Mw) to the average molecular weight (THF-Mw) is not particularly limited, but is usually 1 or more, preferably 1.01 or more, more preferably 1.02 or more, even more preferably 1.05 or more, and most preferably 1.1 or more. The upper limit is not particularly limited, but is usually 3 or less, preferably 2.5 or less, more preferably 2.2 or less, even more preferably 2 or less, and most preferably 1.5 or less. When the NMP-Mw / THF-Mw of hydrogenated nitrile rubber is within this range, the dispersibility and stability of the conductive material dispersion using NMP as a solvent can be greatly improved.

[0080] The ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) (Mw / Mn) of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 1.2 or higher, preferably 1.5 or higher, more preferably 2 or higher, or preferably 2.1 or higher, 2.2 or higher, 2.3 or higher, 2.4 or higher, 2.5 or higher, and 2.6 or higher in that order, and is usually 7 or lower, preferably 6 or lower, more preferably 5 or lower, or preferably 4.7 or lower, 4.5 or lower, 4.3 or lower, 4 or lower, 3.9 or lower, 3.8 or lower, 3.7 or lower, 3.6 or lower, and 3.5 or lower in that order. When the Mw / Mn of the hydrogenated nitrile rubber is within this range, the output characteristics and cycle characteristics of the electrochemical element can be greatly improved.

[0081] The ratio of the Z-average molecular weight (Mz) to the weight-average molecular weight (Mw) (Mz / Mw) of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 1.5 or higher, preferably 1.6 or higher, more preferably 1.7 or higher, or preferably in the order of 1.8 or higher, 1.9 or higher, 2 or higher, 2.1 or higher, 2.2 or higher, and 2.3 or higher, and is usually 7 or lower, preferably 6 or lower, more preferably 5 or lower, or preferably in the order of 4.5 or lower, 4 or lower, 3.5 or lower, and 3 or lower. When the Mz / Mw of the hydrogenated nitrile rubber is within this range, the dispersibility of the conductive material dispersion, the peel strength of the electrode, and the resistance characteristics of the electrochemical element can be improved.

[0082] In the particle size distribution of the hydrogenated nitrile rubber of the present invention , particle diameter when 90% of the total volume is present D90 and Particle size when 10% of the total volume is presentThe ratio of D90 to D10 (D90 / D10) is not particularly limited, but is usually 150 or less, preferably 145 or less, more preferably 140 or less, or preferably 130 or less, 120 or less, 110 or less, 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, and 50 or less, in that order. When the D90 / D10 of the hydrogenated nitrile rubber is within this range, the long-term storage properties of the positive electrode binder can be greatly improved. The lower limit of the D90 / D10 of the hydrogenated nitrile rubber is not particularly limited, but is usually 5 or more, preferably 10 or more, more preferably 15 or more, which can improve the warpage characteristics of the manufactured electrode and the capacitance characteristics of the electrochemical element.

[0083] In the particle size distribution of the hydrogenated nitrile rubber of the present invention The particle diameter (median diameter) when 50% of the total volume is present. D50 and Particle size when 10% of the total volume is present The ratio of D50 to D10 (D50 / D10) is not particularly limited, but is usually 70 or less, preferably 65 or less, more preferably 60 or less, or preferably 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, and 25 or less in that order. When the D50 / D10 of the hydrogenated nitrile rubber is within this range, the long-term storage properties of the positive electrode binder can be greatly improved. The lower limit of the D50 / D10 of the hydrogenated nitrile rubber is not particularly limited, but is usually 1 or more, preferably 3 or more, more preferably 5 or more, which can improve the warpage characteristics of the manufactured electrode and the capacitance characteristics of the electrochemical element.

[0084] The ash content of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 0.7% by mass or less, preferably 0.65% by mass or less, more preferably 0.6% by mass or less, or preferably in the order of 0.55% by mass or less, 0.5% by mass or less, 0.45% by mass or less, 0.4% by mass or less, 0.35% by mass or less, 0.3% by mass or less, 0.25% by mass or less, and 0.2% by mass or less. When the ash content in the hydrogenated nitrile rubber is within this range, it is preferable because it suppresses the increase in resistance when the electrochemical element is stored at high temperatures, and also suppresses the deterioration of capacitance characteristics and cycle characteristics due to the destruction of the negative electrode active material, etc. There is no particular limit to the ash content in hydrogenated nitrile rubber, but it is usually 0.01% by mass or more, preferably 0.02% by mass or more, more preferably 0.03% by mass or more, or preferably in the order of 0.04% by mass or more, 0.05% by mass or more, 0.06% by mass or more, 0.07% by mass or more, 0.08% by mass or more, 0.09% by mass or more, and 0.1% by mass or more, and the hydrogenated nitrile rubber at this level can have its electrode peel strength increased.

[0085] The total amount of calcium (Ca) and sulfur (S) content (Ca+S) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 30% by mass or more, preferably 35% by mass or more, more preferably 40% by mass or more, or preferably in the order of 43% by mass or more, 45% by mass or more, 47% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, and 90% by mass or more. When the total amount of calcium (Ca) and sulfur (S) content (Ca+S) in the ash of the hydrogenated nitrile rubber is within this range, the electrode peel strength is increased, the increase in resistance during high-temperature storage of the electrochemical element is suppressed, and the deterioration of capacity characteristics and cycle characteristics due to the destruction of the negative electrode active material is suppressed.

[0086] The ratio of the total amount of sodium (Na) and potassium (K) content (Na+K) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, or preferably in the order of 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass, 2% by mass or less, and 1% by mass or less. When the ratio of the total amount of sodium (Na) and potassium (K) content (Na+K) in the ash of the hydrogenated nitrile rubber is within this range, the decrease in capacitance characteristics due to the breakdown of the negative electrode active material of the electrochemical element can be suppressed, and the increase in resistance during high-temperature storage can be suppressed.

[0087] The ratio ((Na+K) / (Ca+S)) of the total amount of sodium (Na) and potassium (K) content (Na+K) in the ash of the hydrogenated nitrile rubber of the present invention to the total amount of calcium (Ca) and sulfur (S) content (Ca+S) is not particularly limited, but is usually 0.7 or less, preferably 0.6 or less, more preferably 0.5 or less, or preferably in the order of 0.4 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, 0.1 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, 0.04 or less, and 0.03 or less, is most preferable. When the ratio is within this range, the electrode peel strength is increased, the increase in resistance during high-temperature storage of the electrochemical element is suppressed, and the deterioration of capacitance characteristics and cycle characteristics due to the breakdown of the negative electrode active material is suppressed.

[0088] The calcium content (Ca) and sulfur content (S) in the ash of the hydrogenated nitrile rubber of the present invention mass The ratio (Ca / S) is not particularly limited, but is usually 10 or less, preferably 7 or less, more preferably 5 or less, or 4.5 or less, 4 or less, 3.5 or less, 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, 3 or less, 2.5 or less, 2 or less, 1.5 or less, 1.3 or less, 1.2 or less, 1 .The order of preference is 15 or less, usually 0.1 or more, preferably 0.3 or more, more preferably 0.5 or more, or in the order of 0.6 or more, 0.7 or more, 0.8 or more, and 0.9 or more. The calcium content (Ca) and sulfur content (S) in the ash of hydrogenated nitrile rubber mass When the ratio (Ca / S) is within this range, the electrode peel strength is increased, the increase in resistance during high-temperature storage of the resulting electrochemical element is suppressed, and the decrease in capacitance characteristics due to the breakdown of the negative electrode active material is also suppressed.

[0089] The calcium content (Ca) and chlorine content (Cl) in the ash of the hydrogenated nitrile rubber of the present invention mass The ratio (Ca / Cl) is not particularly limited, but is usually 0.5 or higher, preferably 0.6 or higher, more preferably 0.7 or higher, or preferably in the order of 0.8 or higher, 0.9 or higher, 1 or higher, 1.2 or higher, 1.4 or higher, 1.5 or higher, 1.6 or higher, 1.8 or higher, 2 or higher, 2.5 or higher, 3 or higher, 3.5 or higher, 4 or higher, 5 or higher, 10 or higher, 20 or higher, and 50 or higher, and is usually 100 or lower, preferably 90 or lower, more preferably 80 or lower, even more preferably 75 or lower, and most preferably 70 or lower. The calcium content (Ca) and chlorine content (Cl) in the ash of hydrogenated nitrile rubber mass When the ratio (Ca / Cl) is within this range, the electrode peel strength can be increased, and the degradation of the cycle characteristics of the resulting electrochemical element can be suppressed.

[0090] The sulfur content (S) and chlorine content (Cl) in the ash of the hydrogenated nitrile rubber of the present invention mass The ratio (S / Cl) is not particularly limited, but is usually 0.3 or higher, preferably 0.5 or higher, more preferably 0.7 or higher, or 1 or higher, 1.2 or higher, 1 . The preferred values ​​are in the order of 5 or more, 2 or more, 2.5 or less, 3 or more, 3.5 or more, 4 or more, 4.5 or more, 5 or more, 10 or more, 30 or more, and 50 or more, and usually 100 or less, preferably 90 or less, more preferably 80 or less, even more preferably 75 or less, and most preferably 70 or less. The sulfur content (S) and chlorine content (Cl) in the ash of hydrogenated nitrile rubber massWhen the ratio is within this range, the electrode peel strength is increased, the increase in resistance during high-temperature storage of the electrochemical element is suppressed, and the deterioration of capacitance characteristics and cycle characteristics due to the breakdown of the negative electrode active material is also suppressed.

[0091] The calcium content (Ca) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, most preferably 40% by mass or more, and usually 90% by mass or less, preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, and most preferably 50% by mass or less. When the calcium content (Ca) in the ash of the hydrogenated nitrile rubber is within this range, the electrode peel strength is increased, the increase in resistance during high-temperature storage of the electrochemical element is suppressed, and the deterioration of capacity characteristics and cycle characteristics due to the destruction of the negative electrode active material is suppressed.

[0092] The sulfur content (S) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, most preferably 25% by mass or more, and usually 80% by mass or less, preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less, most preferably 45% by mass or less. When the sulfur content (S) in the ash of the hydrogenated nitrile rubber is within this range, the electrode peel strength is increased, the increase in resistance during high-temperature storage of the electrochemical element is suppressed, and the deterioration of capacity characteristics and cycle characteristics due to the destruction of the negative electrode active material is suppressed.

[0093] The chlorine content (Cl) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, or preferably in the order of 25% by mass or less, 20% by mass or less, 15% by mass or less, and 10% by mass or less. When the chlorine content (Cl) in the ash of the hydrogenated nitrile rubber is within this range, effects such as the cycle characteristics of the electrochemical element and the suppression of resistance increase during high-temperature storage are improved.

[0094] The total amount of sodium (Na) and potassium (K) content (Na+K) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 1500 ppm or less, preferably 1000 ppm or less, more preferably 800 ppm or less, or preferably in the order of 700 ppm or less, 600 ppm or less, 500 ppm or less, 450 ppm or less, 400 ppm or less, 350 ppm or less, 300 ppm or less, 250 ppm or less, 200 ppm or less, 150 ppm or less, and 100 ppm or less. When the total amount of sodium (Na) and potassium (K) content (Na+K) in the ash of the hydrogenated nitrile rubber is within this range, the decrease in battery capacity and cycle characteristics due to the destruction of the negative electrode active material can be suppressed.

[0095] The sodium content (Na) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 700 ppm or less, preferably 500 ppm or less, more preferably 400 ppm or less, or preferably in the order of 350 ppm or less, 300 ppm or less, 250 ppm or less, 200 ppm or less, 150 ppm or less, 100 ppm or less, 70 ppm or less, and 50 ppm or less. When the sodium content (Na) in the ash of the hydrogenated nitrile rubber is within this range, the decrease in battery capacity and cycle characteristics due to the destruction of the negative electrode active material can be suppressed.

[0096] The potassium content (K) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 700 ppm or less, preferably 500 ppm or less, more preferably 400 ppm or less, or preferably in the order of 350 ppm or less, 300 ppm or less, 250 ppm or less, 200 ppm or less, 150 ppm or less, 100 ppm or less, 70 ppm or less, and 50 ppm or less. When the potassium content (K) in the ash of the hydrogenated nitrile rubber is within this range, the decrease in battery capacity and cycle characteristics due to the destruction of the negative electrode active material can be suppressed.

[0097] The total amount of ruthenium (Ru) and rhodium (Rh) content (Ru+Rh) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less, or preferably in the order of 2% by mass or less, 1.5% by mass or less, 1% by mass or less, 0.7% by mass or less, 0.5% by mass or less, 0.3% by mass or less, and 0.1% by mass or less.

[0098] The palladium content (Pd) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less, or preferably in the order of 2% by mass or less, 1.5% by mass or less, 1% by mass or less, 0.7% by mass or less, 0.5% by mass or less, 0.3% by mass or less, and 0.1% by mass or less.

[0099] The metal content (M) ratio used in the hydrogenation catalyst in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but for example, the total amount (Ru+Rh+Pd) of ruthenium content (Ru), rhodium content (Rh), and palladium content (Pd) in the ash is usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less, or preferably in the order of 2% by mass or less, 1.5% by mass or less, 1% by mass or less, 0.7% by mass or less, 0.5% by mass or less, 0.3% by mass or less, and 0.1% by mass or less.

[0100] The phosphorus content (P) in the ash of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, particularly preferably 10% by mass or less, and most preferably 5% by mass or less. When the phosphorus content (P) in the ash of the hydrogenated nitrile rubber is within this range, the cycle characteristics of the resulting electrochemical element are improved and it is preferable.

[0101] The water content of the hydrogenated nitrile rubber of the present invention is not particularly limited, but is usually less than 1% by mass, preferably 0.8% by mass or less, more preferably 0.7% by mass or less, even more preferably 0.6% by mass or less, and most preferably 0.5% by mass or less.

[0102] The hydrogenated nitrile rubber of the present invention is not limited by the manufacturing process, but it is preferably a polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene using an alkali metal salt as a polymerization auxiliary material, and then hydrogenated.

[0103] Polymerization auxiliary materials What is , substances other than monomers and polymerization initiators used to ensure stable emulsion polymerization. It refers to. Examples include emulsifiers, pH adjusters, chain transfer agents (molecular weight adjusters), chelating agents, and reducing agents. There are no particular limitations on alkali metal salts used as polymerization auxiliary materials, but typical examples include potassium fatty acid and sodium dodecylbenzenesulfonate as emulsifiers. Other examples include sodium salts of mono- and di-sulfonated naphthalene sulfonic acid mixtures having isobutylene oligomer substituents, sodium salts of methylenebis(naphthalene sulfonate), and sodium phosphate as a stabilizer. When alkali metal salts such as sodium salts and potassium salts are used as polymerization auxiliary materials, a uniform micelle structure and a uniform polymer can be produced, and the dispersibility and stability of the conductive material dispersion are excellent. However, differences in polymer structure occur that cannot be explained by measurable characteristic values ​​alone, and it is not possible to measure what type or shape of residue remains in the polymer after the polymerization auxiliary materials react. Furthermore, the polymerization auxiliary materials used remain in the crumb formed during the solidification reaction after polymerization and are difficult to remove. However, those using alkali metal salts are preferable because, due to the special crumb shape described later, they are easily removed by washing and dewatering. On the other hand, while the reduction of alkali metal salts from the polymer can be measured by the sodium (Na) and potassium (K) content in the ash, the effect on the properties of hydrogenated hydrogenated nitrile rubber varies greatly depending not only on the amount of Na and K in the ash but also on the type of counteranion, and these cannot be identified.

[0104] The hydrogenated nitrile rubber of the present invention is also preferably obtained by hydrogenating a polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene using sulfates and / or sulfonates as polymerization auxiliary materials.

[0105] Examples of sulfates or sulfonic acids used as polymerization auxiliary materials include emulsifiers such as sodium dodecylbenzenesulfonate, reducing agents such as iron sulfate, sodium salts of mono- and di-sulfonated naphthalene sulfonic acid mixtures having isobutylene oligomer substituents, and sodium salts of methylenebis(naphthalene sulfonate). Polymerization auxiliary materials using sulfates and / or sulfonates are preferable because they are easily removed by cramb washing and dehydration, resulting in minimal impact on the resulting polymer. On the other hand, when examining the ash content in the polymer, when sulfates and / or sulfonates are used as polymerization auxiliary materials and calcium chloride is used as a coagulant, the ratio of calcium content (Ca) to sulfur content (S) in the ash is high, and the calcium and chlorine content of the calcium chloride used as a coagulant are also high. mass The ratio (Ca / Cl) is 0.565, but the calcium content (Ca) and chlorine content (Cl) in the ash are mass The ratio (Ca / Cl) was much larger than this value, suggesting that during the coagulation reaction, some of the readily soluble calcium chloride was exchanged for acidic salts containing poorly hydrophilic (poorly soluble) sulfur, remaining in the polymer. Removing such poorly hydrophilic salts is difficult, but by improving the coagulation reaction, washing, and dehydration processes described later, nitrile rubber with reduced poorly hydrophilic salts was obtained. Hydrogenated nitrile rubber produced by hydrogenating this nitrile rubber suppressed gas generation and degradation of cycle characteristics due to active material breakdown during high-temperature storage of electrochemical elements. It was also found that the presence of poorly hydrophilic salts had the effect of increasing the peel strength of the electrodes. However, the effect of polymers with reduced poorly hydrophilic salts cannot be explained solely by the calcium content (Ca) and sulfur content (S) in the ash, and it is not possible to measure which salts actually affect the stability and dispersibility of the conductive material dispersion and the various properties of the electrochemical element.

[0106] The hydrogenated nitrile rubber of the present invention is preferably obtained by hydrogenating a polymer formed by emulsion polymerization of acrylonitrile and 1,3-butadiene and coagulation with calcium chloride.

[0107] When obtaining polymers by coagulating an emulsion polymerization solution, the size, shape, and properties of the resulting water-containing crumbs vary considerably depending on the type of coagulant used. This results in differences in the polymerization auxiliary materials that can be removed in subsequent washing and dehydration steps, as well as the various auxiliary material residues from the coagulation process. Furthermore, it is impossible to identify all trace amounts of these auxiliary materials and their reaction products. In particular, when hydrogenated nitrile rubber is used in electrochemical elements, these small amounts of residue affect various properties. Therefore, for electrochemical element applications, a solution using calcium chloride as a coagulant is preferable because, even if ash remains in the nitrile rubber or hydrogenated nitrile rubber, it exhibits excellent electrode peel strength characteristics and suppresses gas generation during high-temperature storage of the electrochemical element. Additionally, hydrogenated nitrile rubber obtained by hydrogenating nitrile rubber using alkali metal salts, sulfates, or sulfonates (preferably sulfates or sulfonates) as polymerization auxiliary materials and calcium chloride as a coagulant exhibits excellent electrode peel characteristics for electrochemical elements such as lithium-ion secondary batteries, and suppresses deterioration of cycle characteristics and gas generation during high-temperature storage compared to solutions using other coagulants.

[0108] The hydrogenated nitrile rubber of the present invention is also obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene. Anti-aging agents, among It is preferable that the polymer obtained by adding a phenolic antioxidant and then coagulating it with calcium chloride is hydrogenated.

[0109] The effectiveness of the above-mentioned specific antioxidant is far superior and preferable in nitrile rubber produced by adding it to an emulsion polymerization solution obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene, rather than by mixing it with the nitrile rubber after production. Although this cannot be measured, it is thought that the phenolic antioxidant exhibits a high effect when the emulsion polymerization solution, in which the phenolic antioxidant is uniformly dispersed, is coagulated with calcium chloride, resulting in uniform and fine dispersion within the resulting nitrile rubber. In this invention, the antioxidant effect of the phenolic antioxidant is higher when added in the polymerization solution containing nitrile rubber after emulsion polymerization, rather than in the reaction solution containing hydrogenated nitrile rubber after hydrogenation. However, it is not possible to measure the state in which the antioxidant is thought to be uniformly dispersed in the nitrile rubber or hydrogenated nitrile rubber.

[0110] The hydrogenated nitrile rubber of the present invention is preferably obtained by melt-kneading hydrogenated nitrile rubber containing a phenolic antioxidant.

[0111] The effectiveness of the above-mentioned specific antioxidant can be significantly improved by melt-kneading the hydrogenated nitrile rubber containing the antioxidant using a screw-type twin-screw extruder or similar device. This is presumed to be because the phenolic antioxidant is more uniformly dispersed within the hydrogenated nitrile rubber upon melt-kneading, although this state of uniform dispersion cannot be measured.

[0112] <Method for manufacturing hydrogenated nitrile rubber> The present invention of hydrogenated nitrile Mu is , case Special limit Although not defined, for example, an emulsion polymerization step involves emulsion polymerization of monomer components containing acrylonitrile and 1,3-butadiene to obtain an emulsion polymerization solution, The process involves adding an antioxidant to the resulting emulsion polymerization solution, A coagulation step in which an emulsion polymerization solution to which an antioxidant is added is brought into contact with a coagulation solution to produce a hydrated crumb, The resulting water-containing crumb is washed, dehydrated, and dried in a washing, dehydration, and drying process. The dried polymer is dissolved in an organic solution. medium A hydrogenation step in which the substance is dissolved and a hydrogenation reaction is carried out, A hydrogenated polymer dehydration and drying process is performed in which the reaction solution after the hydrogenation reaction is solidified to produce a water-containing crumb, which is then dehydrated and dried using a screw-type twin-screw extruder to extrude the dried rubber. Including , the invention It can be easily manufactured using the manufacturing method.

[0113] (Emulsion polymerization process) The monomer components used are the same as those described for the monomer components of the repeating units, and the amounts used should be appropriately selected to achieve the monomer composition described above.

[0114] There are no particular limitations on the emulsifiers used in emulsion polymerization; they are selected according to conventional methods. Examples include salts of fatty acids such as myristic acid, palmitic acid, oleic acid, and linolenic acid; alkylbenzene sulfonates such as dodecylbenzenesulfonic acid; sulfate esters such as sodium lauryl sulfate; phosphate esters such as polyoxyalkylene alkyl ether phosphate esters; and alkyl sulfosuccinates. Among these, fatty acid salts, alkylbenzene sulfonates, and sulfate esters are preferred, with fatty acid salts and alkylbenzene sulfonates being particularly preferred.

[0115] Examples of salts such as fatty acid salts, alkylbenzene sulfonates, sulfate esters, and phosphate esters mentioned above include alkali metal salts and ammonium salts, with alkali metal salts being preferred, and sodium salts and potassium salts being particularly preferred. Specific examples of emulsifiers include potassium oleate, sodium oleate, potassium palmitate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, ammonium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkyl sulfate, and sodium polyoxyethylene alkylaryl sulfate, with potassium oleate and sodium dodecylbenzenesulfonate being preferred.

[0116] These emulsifiers can be used individually or in combination of two or more, and the amount used is usually in the range of 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 1 to 3 parts by mass, per 100 parts by mass of monomer component.

[0117] The method for mixing the monomer component, emulsifier, and water can be done according to conventional methods, such as stirring the monomer, emulsifier, and water using a homogenizer or a stirrer such as a disk turbine. The amount of water used is usually in the range of 10 to 750 parts by mass, preferably 50 to 500 parts by mass, and more preferably 100 to 400 parts by mass, per 100 parts by mass of the monomer component.

[0118] In addition to the emulsifiers mentioned above, known materials used in emulsion polymerization can be used as polymerization auxiliary materials, after being appropriately optimized. Specifically, molecular weight regulators (chain transfer agents), pH adjusters, etc. Adjustment Various polymerization regulators can be used, including catalysts, stabilizers, and reducing and chelating agents in redox catalysts.

[0119] There are no particular limitations on the polymerization initiator used in emulsion polymerization, as long as it is one that is commonly used in emulsion polymerization; for example, a radical generator can be used.

[0120] Examples of radical generators include peroxides and azo compounds, with peroxides being preferred. Inorganic or organic peroxides are used. Organic peroxides are preferred to increase the number of 1,2-bond units in the 1,3-butadiene polymerization units of nitrile rubber.

[0121] Examples of inorganic peroxides (inorganic polymerization initiators) include sodium persulfate, potassium persulfate, hydrogen peroxide, and ammonium persulfate. Among these, potassium persulfate, hydrogen peroxide, and ammonium persulfate are preferred, with potassium persulfate being particularly preferred.

[0122] As for organic peroxides (organic polymerization initiators), there are no particular limitations as long as they are known to be used in emulsion polymerization. For example, 2,2-di(4,4-di-(t-butylperoxy)cyclohexyl)propane, 1-di-(t-hexylperoxy)cyclohexane, 1,1-di-(t-butylperoxy)cyclohexane, 4,4-di-(t-butylperoxy)n-butyl valerate, 2,2-di-(t-butylperoxy)butane, t-butyl hydroperoxide, cumene hydroperoxide, diisopropyl Examples include pyrubenzene hydroperoxide, paramentane hydroperoxide, benzoyl peroxide, 1,1,3,3-tetraethylbutyl hydroperoxide, t-butylcumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, diisobutyryl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, and dilauroyl peroxide.

[0123] These polymerization initiators can be used individually or in combination of two or more types, and the amount used is usually in the range of 0.0001 to 5 parts by mass, preferably 0.0005 to 1 part by mass, and more preferably 0.001 to 0.5 parts by mass, per 100 parts by mass of monomer component.

[0124] The amount of water used in the emulsion polymerization reaction may be limited to the amount used during the emulsion formation of the monomer components, but it is usually adjusted to be in the range of 10 to 1000 parts by mass, preferably 50 to 500 parts by mass, more preferably 80 to 400 parts by mass, and most preferably 100 to 300 parts by mass, per 100 parts by mass of the monomer components used for polymerization.

[0125] The emulsion polymerization reaction can be carried out according to conventional methods and may be batch, semi-batch, or continuous. The polymerization temperature and polymerization time are not particularly limited and can be appropriately selected depending on the type of polymerization initiator used. The polymerization temperature is usually in the range of 0 to 100°C, preferably 10 to 90°C, more preferably 20 to 80°C, even more preferably 25 to 70°C, and most preferably 30 to 60°C, and the polymerization time is usually 0.5 to 100 hours, preferably 1 to 10 hours. By setting the polymerization temperature higher, the 1,2-bonding units in the 1,3-butadiene polymerization units of the nitrile rubber, or the Mw / Mn and Mz / Mw of the nitrile rubber can be increased.

[0126] The polymerization conversion rate in the emulsion polymerization reaction is not particularly limited, but is usually 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more. Setting a higher polymerization conversion rate can increase the 1,2-bonding units in the 1,3-butadiene polymerization units of the nitrile rubber, or the Mw / Mn and Mz / Mw of the nitrile rubber. A polymerization inhibitor may be used to stop the polymerization.

[0127] (Addition of anti-aging agent) In this invention ,above An anti-aging agent is added to the emulsion polymerization solution after emulsion polymerization. ru. Adding an antioxidant to the emulsion polymerization solution is preferable because it allows for uniform dispersion of the antioxidant in the resulting nitrile rubber or hydrogenated nitrile rubber. Furthermore, adding the antioxidant at this stage is preferable because it prevents degradation reactions during the drying of the nitrile rubber.

[0128] The antioxidant used is the same as the example of the antioxidant contained in the hydrogenated nitrile rubber, and the method of adding the antioxidant to the emulsion polymerization solution is not particularly limited and can be done according to conventional methods. For example, it may be added as is, or it may be added after being emulsified with an emulsifier.

[0129] The amount of antioxidant used can be appropriately selected to match the amount of antioxidant in the hydrogenated nitrile rubber of the present invention, but is typically in the range of 0.001 to 15 parts by mass, preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, particularly preferably 0.3 to 3 parts by mass, and most preferably 0.5 to 2 parts by mass per 100 parts by mass of monomer component.

[0130] The emulsion polymerization solution after the addition of the antioxidant can be pH-adjusted with a buffer solution (sulfuric acid aqueous solution, potassium hydroxide aqueous solution) as needed. Adjusting the pH at this stage is preferable because it allows control of the pH of the hydrogenated nitrile rubber and removes impurities derived from the buffer solution.

[0131] The pH of the emulsion polymerization solution is not particularly limited, but is usually 2 or higher, preferably 2.5 or higher, more preferably 3 or higher, or preferably 3.5 or higher, 4 or higher, and 4.5 or higher in that order, and is usually 8 or lower, preferably 7.5 or lower, more preferably 7 or lower, even more preferably 6.5 or lower, and most preferably 6 or lower. By setting the pH of the emulsion polymerization solution within this range, the hydrogenated nitrile rubber produced can enhance the viscosity stability of the positive electrode slurry and improve the capacitance and resistance characteristics of the electrochemical element.

[0132] (solidification process) The coagulation reaction is a coagulation solution. Preferably This process involves using an aqueous calcium chloride solution and contacting it with an emulsion polymerization solution to generate a hydrated crumb. In particular, in the present invention, the emulsion polymerization solution to which the above-mentioned antioxidant has been added is added to a coagulation solution that is being vigorously stirred. preferred .

[0133] The solid content concentration of the emulsion polymerization solution used is not particularly limited, but is usually adjusted to a range of 5 to 50% by mass, preferably 10 to 45% by mass, and more preferably 20 to 40% by mass.

[0134] While there are no particular limitations on the concentration of the coagulation solution used, it is generally preferable to use a concentration of 0.1 to 70% by mass, preferably 1 to 60% by mass, more preferably 5 to 50% by mass, and especially preferably 10 to 30% by mass, as this allows for the concentration of the water-containing crumb particle size within a specific range.

[0135] While there are no particular limitations on the temperature during the coagulation reaction, it is generally preferable to have a temperature of 0°C or higher, preferably 10 to 90°C, and more preferably 20 to 80°C, as this is when a uniform hydrated crumb is produced.

[0136] The contact between the emulsion polymerization solution and the coagulation solution is preferably carried out by adding the emulsion polymerization solution to the coagulation solution while it is being vigorously stirred, which significantly improves the washing and dewatering efficiency of the resulting water-containing crumb. Furthermore, the position at which the emulsion polymerization solution is added to the coagulation solution is where it is added. twist Preferably, the crumb is added to the coagulation solution after being directly exposed to the vigorously agitating blades, which significantly improves the washing and dewatering efficiency of the resulting water-containing crumb. The water-containing crumb produced by this coagulation method is preferable because it significantly improves the washing and dewatering efficiency of emulsifiers and coagulants.

[0137] There are no particular limitations on the rotation speed of the impeller, but it is usually 100 rpm or more, preferably 200 rpm or more, more preferably 300 rpm or more, or preferably 350 rpm or more, 400 rpm or more, 450 rpm or more, 500 rpm or more, and 550 rpm or more in that order, and usually 1000 rpm or less, preferably 900 rpm or less, more preferably 800 rpm or less, even more preferably 750 rpm or less, and most preferably 700 rpm or less. It is preferable that the rotation speed of the impeller is above a certain level and the solidified liquid is vigorously stirred so that the diameter of the water-containing crumbs generated can be made smaller and concentrated in a specific region.

[0138] The peripheral velocity of the stirred solidified liquid is expressed as the linear velocity of the outer circumference of the stirring blade of the stirring device. It is preferable that the solidified liquid is stirred vigorously to a certain extent, as this makes it possible to create smaller and more uniform water-containing cramb diameters. Typically, a peripheral velocity of 0.5 m / s or more is suitable, preferably 1 m / s or more, more preferably 1.5 m / s or more, particularly preferably 2 m / s or more, and most preferably 2.5 m / s or more. There is no particular upper limit to the peripheral velocity of the stirred solidified liquid, but it is usually 50 m / s or less, preferably 30 m / s or less, more preferably 25 m / s or less, and particularly preferably 20 m / s or less, as this facilitates control of the solidification reaction.

[0139] As for the water-containing crumbs that are generated, for example, when sieving (classification) is performed using a JIS classifying sieve under the conditions (a) to (g) below, the proportion of water-containing crumbs with a diameter of 1.7 to 8 mm (passing through an 8 mm mesh opening but not a 1.7 mm mesh opening) to the generated water-containing crumbs is not particularly limited, but is usually 30% by mass or more, preferably 40% by mass or more, more preferably 50% by mass or more, or preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, and 90% by mass or more in that order. When the particle size of the generated water-containing crumbs is within this range, the washing efficiency and dewatering efficiency can be significantly increased, the ash content in the nitrile rubber can be reduced, and as a result the ash content in the hydrogenated nitrile rubber can be reduced.

[0140] The proportion of water-containing crumbs with a diameter of 2.36 to 4.75 mm (passing through a 4.75 mm opening but not through a 2.36 mm opening) to the generated water-containing crumbs is not particularly limited, but is usually 20% by mass or more, preferably 30% by mass or more, more preferably 40% by mass or more, or preferably 50% by mass or more, 60% by mass or more, 70% by mass or more, and 80% by mass or more, in that order. When the particle size of the generated water-containing crumbs is within this range, the washing efficiency and dewatering efficiency can be significantly increased, the ash content in the nitrile rubber can be reduced, and as a result the ash content in the hydrogenated nitrile rubber can be reduced.

[0141] The resulting hydrated crumb must satisfy all of the following conditions (a) to (e). RumoThis is preferable because it significantly improves the efficiency of removing emulsifiers and coagulants during washing and dewatering.

[0142] (a) The percentage of water-containing crumbs that do not pass through a JIS sieve with a mesh size of 9.5 mm is usually 10 quality Less than % by amount, preferably 5% by mass or less, more preferably teeth 3 mass %below That is the case. (b) The proportion of relatively large water-containing crumbs that pass through a JIS sieve with a mesh size of 9.5 mm but do not pass through a JIS sieve with a mesh size of 8 mm is usually The amount is 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and most preferably 5% by mass or less. (c) The percentage of water-containing crumbs that pass through a JIS sieve with an 8mm mesh opening but do not pass through a JIS sieve with an 1.7mm mesh opening is usually The amount is 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and most preferably 90% by mass or more. (d) The percentage of water-containing crumbs that pass through a 1.7 mm mesh sieve but not through a 0.43 mm mesh sieve is usually The amount is 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and most preferably 5% by mass or less. (e) The percentage of water-containing crumbs that pass through a JIS sieve with a mesh opening of 0.43 mm is usually The amount is 10% by mass or less, preferably 5% by mass or less, and more preferably 3% by mass or less.

[0143] Furthermore, it is preferable that the resulting hydrated crumb satisfies the following conditions (f) and / or (g). (f) The percentage of water-containing crumbs that pass through a JIS sieve with a mesh size of 4.75 mm but do not pass through a JIS sieve with a mesh size of 2.36 mm is usually The amount is 30% by mass or more, preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and most preferably 70% by mass or more. (g) The percentage of water-containing crumbs that pass through a JIS sieve with a mesh size of 4.75 mm but do not pass through a JIS sieve with a mesh size of 3.35 mm is usually The water content is 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and most preferably 30% by mass or more. Furthermore, there is no particular limit to the upper limit of the water-containing crumb within this range, but it is usually 90% by mass or less, preferably 85% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, and most preferably 70% by mass or less.

[0144] The shape of the resulting water-containing crumbs is not particularly limited, but a perforated shape is preferred. In particular, adding the emulsion polymerization solution directly to the central rotating shaft and rotor blades in the vigorously rotating solidifying liquid increases the amount of perforated water-containing crumbs, which is preferable.

[0145] After the solidification process, the resulting water-containing crumb can be washed, dehydrated, and dried to obtain the polymer before hydrogenation.

[0146] (Washing process) Using warm water is preferable as a cleaning method. The ideal temperature for the hot water is typically 30°C or higher, preferably 35-100°C, more preferably 40-80°C, even more preferably 40-60°C, and most preferably 40-50°C, as this significantly improves cleaning efficiency. Calcium sulfate and calcium sulfonate salts, for example, are poorly soluble in water and have low solubility, but their solubility tends to increase at certain temperatures. By setting the cleaning water temperature above the aforementioned lower limit, emulsifiers and coagulants are released from the water-containing crumb, further improving cleaning efficiency.

[0147] The hydrated crumb, solidified in a high-concentration coagulation solution (aqueous calcium chloride solution) during the coagulation process, is effectively washed with a large amount of water. The amount of water used is typically 10 to 500 times, preferably 25 to 250 times, and more preferably 50 to 100 times, by mass per 100 parts by mass of polymer.

[0148] There are no particular limitations on the washing time, but it is usually in the range of 1 to 120 minutes, preferably 2 to 60 minutes, and more preferably 3 to 30 minutes.

[0149] (Dehydration process) Washed, water-containing crumb is preferable because dehydration removes polymerization auxiliary materials such as emulsifiers trapped inside the water-containing crumb.

[0150] The water content of the dehydrated crumb is not particularly limited, but is usually 35% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less, or preferably in the order of 20% by mass or less, 15% by mass or less, 14% by mass or less, 13% by mass or less, 12% by mass or less, 10% by mass or less, 8% by mass or less, and 7% by mass or less.

[0151] There are no particular limitations on the method for dehydrating water-containing crumb, but a method that compresses and dehydrates the crumb using a squeezer or similar device to extract the internal moisture is preferable. On the other hand, dehydration using a centrifuge or similar device is insufficient as it can only reduce the water content of the crumb to about 50-60% by mass.

[0152] The dehydration temperature is not particularly limited, but is usually 30°C or higher, preferably 40°C or higher, more preferably 50°C or higher, or preferably 60°C or higher, 70°C or higher, 80°C or higher, and 90°C or higher in that order. At this temperature range, the water-containing crumb becomes flexible, making it easier to remove moisture containing polymerization auxiliary materials, etc.

[0153] (drying process) The drying method for the water-containing crumb after dehydration described above can be followed according to conventional methods, and can be used, for example, with a hot air dryer, vacuum dryer, expander dryer, kneader dryer, screw-type twin-screw extruder dryer, or other dryer.

[0154] The shape of the dried rubber (polymer) is not particularly limited and can be, for example, crumb-like, powder-like, rod-like, or sheet-like. The water content of the dried rubber is not particularly limited, but is usually less than 1% by mass, preferably 0.9% by mass or less, more preferably 0.8% by mass or less, even more preferably 0.6% by mass or less, and most preferably 0.5% by mass or less.

[0155] The nitrile rubber thus obtained can, if necessary, be subjected to a double decomposition reaction followed by a hydrogenation reaction to produce hydrogenated nitrile rubber.

[0156] (Double decomposition reaction) The double decomposition reaction of nitrile rubber can be carried out using, for example, the ruthenium catalyst described in Japanese Patent No. 4509792.

[0157] There are no particular limitations on the ruthenium-based catalyst used; any known ruthenium-based catalyst can be used. In particular, it is preferable to use Grubbs catalysts such as bis(tricyclohexylphosphine)benzylideneruthenium dichloride or 1,3-bis(2,4,6-trimethylphenyl)-2-(imidazolidinylidene)(dichlorophenylmethylene)(tricyclohexylphosphine)ruthenium.

[0158] The double decomposition reaction is carried out by dissolving the substance in a solvent in the presence of a coolefin. Examples of coolefins include olefins with 2 to 16 carbon atoms such as ethylene, isobutane, styrene, and 1-hexane, as well as cis-2-butene-1,4-diol, 3-butene-1-amine, vinyltrimethoxysilane, methoxypolyalkylene glycol methacrylate, and 2-(methacryloyloxy)ethanesulfonic acid.

[0159] The amount of coolefin used is typically in the range of 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of polymer.

[0160] The reaction can be carried out in a solvent that does not inactivate the catalyst or interfere with the reaction. Preferred solvents are not limited to dichloromethane, but include, for example, dichloromethane, benzene, toluene, tetrahydrofuran, cyclohexane, and monochlorobenzene (MCB), with MCB being preferred. In some cases, the coolefin itself can act as a solvent, in which case no other solvent is required.

[0161] The polymer concentration in the double decomposition reaction is not particularly limited, but is usually in the range of 1 to 20% by mass, preferably 6 to 15% by mass.

[0162] The reaction solution in the double decomposition reaction is usually stirred vigorously, for example, in the range of 200 to 1000 rpm, preferably 300 to 900 rpm, and more preferably 500 to 800 rpm.

[0163] The temperature for the double decomposition reaction is typically in the range of 20 to 140°C, preferably 60 to 120°C. The reaction time depends on numerous factors, including the cement concentration, the amount of catalyst used, and the reaction temperature, but is usually completed within 2 hours. The progress of the double decomposition reaction can be monitored using standard analytical methods, such as GPC or solution viscosity.

[0164] (Hydrogenation reaction) The hydrogenation reaction is carried out using nitrile rubber, or nitrile rubber that has undergone the double decomposition reaction as needed, as a solvent. (organic solvent) This can be done by dissolving the solution and adding a hydrogenation catalyst.

[0165] While there are no particular limitations on the solvent for the hydrogenation reaction, organic solvents that provide high hydrogenation efficiency for nitrile rubber are preferred. Suitable organic solvents include, for example, acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, 1,3-dioxane, benzene, toluene, methylene chloride, chloroform, monochlorobenzene (MCB), and dichlorobenzene. Among these, MCB is particularly preferred as it is a good solvent for both the nitrile group-containing nitrile rubber before hydrogenation and the hydrogenated nitrile rubber after hydrogenation.

[0166] There are no particular limitations on the hydrogenation catalyst, but it is usually carried out using a ruthenium-based catalyst. When the above double decomposition reaction is carried out using the Grubbs catalyst, it can be converted to the olefin hydrogenation catalyst dihydrogen complex (PR3) 2RuCl2H2 by hydrogen substitution in the reactor, and the reaction can be continued. Alternatively, a dihydrogen complex or other ruthenium-based catalyst can be used. The hydrogenation reaction can be carried out according to a conventional method, for example, by the method described in Japanese Patent No. 6309634.

[0167] While there are no particular limitations on hydrogenation catalysts other than ruthenium-based catalysts, known homogeneous hydrogenation catalysts such as rhodium-based Wilkinson catalysts ((PPh3)3RhCl) are particularly preferred because they can be used with the same solvent as ruthenium-based catalysts and can be carried out without changing the reaction vessel. The hydrogenation reaction can be carried out according to a conventional method, for example, by the method described in Japanese Patent No. 6309634. In the case of Wilkinson catalysts, co-catalysts include phosphine, diphosphine, and triphenylphosphine, with triphenylphosphine being preferred. The amount of these co-catalysts used is usually 0.01 to 15 parts by mass based on 100 parts by mass of the polymer to be hydrogenated. Department Preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass Department It is within the range of [the specified range].

[0168] The amount of hydrogenation catalyst used can be appropriately selected according to the purpose of use and the iodine value, but is usually in the range of 0.001 to 0.5 parts by mass, preferably 0.005 to 0.1 parts by mass, or 0.01 to 0.05 parts by mass, based on 100 parts by mass of polymer before hydrogenation.

[0169] The polymer concentration in the hydrogenation reaction is not particularly limited as long as the polymer can be dissolved, but is usually in the range of 1 to 30% by mass, preferably 5 to 25% by mass, and more preferably 7 to 20% by mass.

[0170] The pressure for the hydrogenation reaction is not particularly limited, but is usually in the range of 0.1 to 30 MPa, preferably 1 to 20 MPa, and more preferably 5 to 15 MPa.

[0171] The hydrogenation reaction temperature is typically in the range of 30 to 200°C, preferably 50 to 170°C, and more preferably 100 to 150°C. The reaction time is typically 1 to 50 hours, preferably 2 to 25 hours.

[0172] The hydrogenation reaction can be stopped by reducing the pressure or cooling the reactor once the desired hydrogenation level is reached. Any remaining hydrogen is usually removed by nitrogen purging. The hydrogenation catalyst can also be removed before removing the solvent and isolating the hydrogenated nitrile rubber from the organic layer.

[0173] (Catalyst removal process) After the hydrogenation reaction, the hydrogenation catalyst can be removed as needed, and then the rubber can be dried to obtain hydrogenated nitrile rubber.

[0174] The hydrogenation catalyst can be removed by conventional methods, and for example, adsorbent treatment is preferred. The adsorbent is not particularly limited, but examples include activated carbon, ion exchange resin, and synthetic zeolite, with ion exchange resin being preferred.

[0175] The adsorbent treatment can be carried out by adding and mixing the adsorbent to the reaction solution containing hydrogenated nitrile rubber after hydrogenation. There are no particular limitations on the amount of adsorbent to add, but it is usually in the range of 0.001 to 1 part by mass, preferably 0.05 to 0.5 parts by mass, and more preferably 0.01 to 0.4 parts by mass, per 100 parts by mass of hydrogenated nitrile rubber. The mixing temperature is usually in the range of room temperature to 80°C, preferably room temperature to 60°C, and the mixing time is usually 1 minute to 1 hour, preferably 20 to 40 minutes.

[0176] After the adsorption treatment, the adsorbent can be removed by filtration or decantation, and the filtrate can be dried to obtain hydrogenated nitrile rubber.

[0177] <Recovery of hydrogenated nitrile rubber using a screw-type twin-screw extruder> In the present invention, the water-containing crumb produced by coagulating the organic solvent reaction solution after the hydrogenation reaction, or the filtrate of the organic solvent system after the adsorption treatment and filtration, is dehydrated and dried using a screw-type twin-screw extruder. (solidification process) The solidification process for the hydrogenated nitrile rubber filtrate, obtained from the purification process (hydrogenation catalyst removal process) described above, is not particularly limited and can be carried out according to conventional methods. Specific solidification methods include contact with a coagulant and contact with a large amount of poor solvent, with contact with a large amount of poor solvent being preferred. While there are no particular limitations on the poor solvent, methanol, water, and steam are preferably used. The solidification reaction can be appropriately selected; for example, the solidification reaction temperature is usually in the range of room temperature to 100°C, and the solidification reaction time is appropriately selected within the range of several minutes to several hours.

[0178] The hydrous nitrile rubber crumb produced by the coagulation reaction can be washed as needed. While there are no particular limitations on the washing method, and any conventional method may be used, washing with a large amount of water is efficient. The amount of water used is typically 10 to 500 times, preferably 25 to 250 times, and more preferably 50 to 100 times, by mass per 100 parts by mass of polymer. While there are no particular limitations on the temperature of the water used for washing, warm water is preferable, typically 40°C or higher, preferably 40 to 100°C, more preferably 50 to 90°C, and most preferably 60 to 80°C, as this significantly improves washing efficiency. By raising the washing water temperature above the aforementioned lower limit, emulsifiers and coagulants are released from the hydrous crumb, further improving washing efficiency.

[0179] After coagulation or washing, the water-containing crumb can be isolated by filtration.

[0180] (Dewatering and drying process using a screw-type twin-screw extruder) In this invention, the water-containing crumb of the isolated hydrogenated nitrile rubber is dried using a screw-type twin-screw extruder. The hydrogenated nitrile rubber is dried under reduced pressure in the screw-type twin-screw extruder. to By melt-mixing and drying, the internal air is removed, resulting in a dry rubber (hydrogenated nitrile rubber) with a high bulk density. When used as a positive electrode material, it exhibits excellent dispersion stability with conductive materials, and is suitable for preventing peel strength of electrochemical element electrodes and cracking of the active material layer after cycle testing.

[0181] Dehydration of the dehydration barrel Dewatering of the water-containing crumb is performed in a dewatering barrel equipped with dewatering slits. The opening of the dewatering slits can be appropriately selected according to the usage conditions, but it is generally preferable that it is in the range of 0.1 to 1 mm, preferably 0.2 to 0.6 mm, as this minimizes the loss of water-containing crumb and allows for efficient dewatering.

[0182] The number of dewatering barrels in a screw-type twin-screw extruder dryer is not particularly limited, but it is generally preferable to have several barrels, preferably 2 to 10, and more preferably 3 to 6, for efficient dewatering of sticky hydrogenated nitrile rubber.

[0183] The set temperature of the dewatering barrel is appropriately selected depending on the type of hydrogenated nitrile rubber, ash content, water content, and operating conditions, but is usually in the range of 60 to 150°C, preferably 70 to 140°C, and more preferably 80 to 130°C. The set temperature of the dewatering barrel for dewatering in a drainage state is usually in the range of 60 to 120°C, preferably 70 to 110°C, and more preferably 80 to 100°C. The set temperature of the dewatering barrel for drying in a drain steam state is usually in the range of 100 to 150°C, preferably 105 to 140°C, and more preferably 110 to 130°C.

[0184] There are no particular limitations on the water content after dehydration, which is obtained by squeezing out the water from the water-containing crumb, but it is usually 1 to 45% by mass, preferably 1 to 40% by mass, more preferably 3 to 35% by mass, and especially preferably 5 to 35% by mass.

[0185] Drying of the drying barrel section The water-containing crumb, dehydrated in the dehydration barrel section, is further dried in a drying barrel section under reduced pressure. The degree of vacuum in the drying barrel can be selected as appropriate, but it is generally preferable to set it to 1-50 kPa, preferably 2-30 kPa, and more preferably 3-20 kPa, as this allows for efficient drying of the water-containing crumb. Furthermore, as the molten hydrogenated nitrile rubber is extruded through the reduced-pressure drying barrel, the internal air is also removed, resulting in a high bulk density sheet-like hydrogenated nitrile rubber. but It is suitable for manufacturing.

[0186] The drying barrel temperature can be selected as appropriate, but typically, a temperature in the range of 100 to 250°C, preferably 110 to 200°C, and more preferably 120 to 180°C, allows for efficient drying without burning or deterioration of the hydrogenated nitrile rubber.

[0187] The number of drying barrels in a screw-type twin-screw extruder dryer is not particularly limited, but is usually several, preferably 2 to 10, more preferably 3 to 8. When there are multiple drying barrels, the degree of vacuum may be similar for all drying barrels, or it may be varied. Drying barrels of When using multiple units, the set temperatures can be similar for all drying barrels or varied. However, it is preferable to set the temperature at the discharge section (closer to the die) higher than the temperature at the inlet section (closer to the dewatering barrel) to improve drying efficiency.

[0188] The water content of the dried rubber after drying is usually less than 1% by mass, preferably 0.8% by mass or less, and more preferably 0.6% by mass or less.

[0189] Extrusion of hydrogenated nitrile rubber (die section) The hydrogenated nitrile rubber, dewatered and dried in the screw section of the dewatering barrel and drying barrel described above, is sent to a die section without a screw for straightening the flow. A breaker plate or wire mesh may or may not be provided between the screw section and the die section.

[0190] The extruded hydrogenated nitrile rubber can be obtained in various shapes, such as granular, columnar, round rod, or sheet, depending on the die nozzle shape. However, using a roughly rectangular die shape to extrude the rubber in sheet form is preferable because it reduces air entrapment, increases bulk density, and provides excellent storage stability, resulting in a dry rubber.

[0191] The resin pressure in the die section is not particularly limited, but it is generally preferable to set it in the range of 0.1 to 10 MPa, preferably 0.5 to 5 MPa, and more preferably 1 to 3 MPa, as this minimizes air entrapment and provides excellent productivity.

[0192] Screw-type twin-screw extruder dryer and operating conditions The screw length (L) of the screw-type twin-screw extruder dryer used can be appropriately selected according to the intended use, but is typically in the range of 3,000 to 15,000 mm, preferably 4,000 to 10,000 mm, and more preferably 4,500 to 8,000 mm.

[0193] The screw diameter (D) of the screw-type twin-screw extruder dryer used can be appropriately selected depending on the intended use, but is typically in the range of 50 to 250 mm, preferably 100 to 200 mm, and more preferably 120 to 160 mm.

[0194] The ratio (L / D) of the screw length (L) to the screw diameter (D) of the screw-type twin-screw extruder dryer used is not particularly limited, but is usually in the range of 10 to 100, preferably 20 to 80, more preferably 30 to 60, and especially preferably 40 to 50, when it is possible to reduce the water content to less than 1% by mass without causing a decrease in molecular weight or burning of the dried rubber.

[0195] The rotational speed (N) of the screw-type twin-screw extruder dryer used can be appropriately selected according to various conditions, but is usually 10 to 1000 rpm, preferably 50 to 750 rpm, more preferably 100 to 500 rpm, and most preferably 120 to 300 rpm.

[0196] The extrusion rate (Q) of the screw-type twin-screw extruder dryer used is not particularly limited, but is usually in the range of 100 to 1,500 kg / hr, preferably 300 to 1,200 kg / hr, more preferably 400 to 1,000 kg / hr, and most preferably 500 to 800 kg / hr.

[0197] The ratio (Q / N) of the extrusion rate (Q) to the rotational speed (N) of the screw-type twin-screw extruder dryer used is not particularly limited, but is usually in the range of 2 to 10, preferably 3 to 8, and more preferably 4 to 6.

[0198] Dry rubber The shape of the dried rubber extruded from a screw-type twin-screw extruder is not particularly limited, and examples include crumbs, powders, rods, and sheets, with the sheet shape being particularly preferred.

[0199] <Hydrogenated Nitrile Rubber Bale> The hydrogenated nitrile rubber bale of the present invention can be manufactured by forming a bale of the dried hydrogenated nitrile rubber described above.

[0200] The hydrogenated nitrile rubber bale of the present invention is made of the hydrogenated nitrile rubber, and by forming it into a bale, the effects of the hydrogenated nitrile rubber of the present invention can be maintained even during storage, making it suitable.

[0201] The shape of the hydrogenated nitrile rubber bale of the present invention is not particularly limited, but is usually rectangular. The size is not particularly limited, but the width is usually in the range of 100 to 800 mm, preferably 200 to 500 mm, more preferably 250 to 450 mm; the length is usually in the range of 300 to 1200 mm, preferably 400 to 1000 mm, more preferably 500 to 800 mm; and the height is usually in the range of 50 to 500 mm, preferably 100 to 300 mm, more preferably 150 to 250 mm.

[0202] Iodine value, type and concentration of antioxidant for the hydrogenated nitrile rubber bale of the present invention 、Ash content, ratio of the total amount of calcium (Ca) and sulfur (S) in the ash (Ca+S), ratio of the total amount of sodium (Na) and potassium (K) in the ash (Na+K), and ratio of sodium (Na), potassium (K), calcium (Ca), and sulfur (S) in the ash mass The ratio ((Na+K) / (Ca+S)) is the ratio of calcium content (Ca) to sulfur content (S) in the ash. mass The ratio (Ca / S), the calcium content (Ca) and chlorine content (Cl) in the ash. mass The ratio (Ca / Cl), the sulfur content (S) and chlorine content (Ca) in the ash. mass Ratio (S / Cl), percentage of metal content (M) in the hydrogenation catalyst in the ash, percentage of total ruthenium content (Ru) and rhodium content (Rh) in the ash (Ru+Rh), percentage of palladium content (Pd) in the ash, sodium content in the ash (Na) and potassium content (K) The total amount (Na+K), sodium content in the ash (Na), potassium content in the ash (K), and polymer pH are the same as those described for hydrogenated nitrile rubber.

[0203] The bulk density of the hydrogenated nitrile rubber bale of the present invention is not particularly limited, but is typically 0.6 g / cm³. 3 Preferably, 0.63 g / cm³ 3 More preferably 0.65 g / cm³ 3 That is all, or 0.7 g / cm³ 3 More than 0.73g / cm 3 More than 0.75g / cm 3 More than 0.77g / cm 3 More than 0.8g / cm 3 More than 0.83g / cm 3 More than 0.85g / cm 3 More than 0.87g / cm 3 More than 0.9g / cm 3 More than 0.91g / cm 3 More than 0.92g / cm 3 More than 0.93g / cm 3 More than 0.94g / cm 3 More than 0.95g / cm3 The above order of preference is preferred. When the bulk density of the hydrogenated nitrile rubber veil is within this range, the effect of the antioxidant, especially the phenolic antioxidant, is greatly enhanced, the stability of the conductive material dispersion is excellent, and the cycle characteristics of the electrochemical element and active material cracking after cycle testing can be prevented.

[0204] The water content of the hydrogenated nitrile rubber bale of the present invention is not particularly limited, but is generally less than 1% by mass, preferably 0.8% by mass or less, and more preferably 0.6% by mass or less, as it provides excellent storage stability and is therefore preferable.

[0205] The Mooney viscosity (ML1+4, 100°C) of the hydrogenated nitrile rubber bale of the present invention is not particularly limited, but is generally in the range of 10 to 150, preferably 15 to 100, and more preferably 20 to 80, when the dispersibility of conductive materials and peel strength at the electrode are well balanced and preferable.

[0206] The baling of dried hydrogenated nitrile rubber can be carried out by conventional methods. For example, the dried rubber can be placed in a baler and compressed. The compression pressure is appropriately selected depending on the intended use, but is usually in the range of 0.1 to 15 MPa, preferably 0.5 to 10 MPa, and more preferably 1 to 5 MPa. The compression time is not particularly limited, but is usually in the range of 1 to 60 seconds, preferably 5 to 50 seconds, and more preferably 10 to 40 seconds. Alternatively, dried rubber can be made in sheet form and then laminated to form bales. Baling by laminating sheets is easy to manufacture, produces bales with fewer air bubbles (higher bulk density), and is preferable due to its excellent storage stability.

[0207] In the present invention, a suitable hydrogenated nitrile rubber bale with a high bulk density can be easily manufactured by laminating the sheet-like dried rubber (hydrogenated nitrile rubber) extruded from the screw-type twin-screw extruder.

[0208] <Positive electrode materials and binders for positive electrodes> The positive electrode material of the present invention is characterized by using the hydrogenated nitrile rubber of the present invention.

[0209] The positive electrode binder of the present invention is obtained by dissolving the hydrogenated nitrile rubber in N-methylpyrrolidone (NMP), and is suitable as a material for manufacturing the positive electrode of an electrochemical element. Furthermore, the positive electrode binder of the present invention is for example, Nitrile rubber can be easily produced by adding an NMP solution to a monochlorobenzene solution containing hydrogenated nitrile rubber after a hydrogenation reaction of nitrile rubber in monochlorobenzene, and then removing the monochlorobenzene solvent by distillation and performing solvent replacement.

[0210] The positive electrode binder of the present invention may combine other components as needed, in addition to hydrogenated nitrile rubber and NMP. These other components are not particularly limited, but examples include binders other than hydrogenated nitrile rubber (such as polyvinylidene fluoride or polyacrylate), reinforcing agents, leveling agents, viscosity modifiers, and electrolyte additives. These are not particularly limited as long as they do not affect the battery reaction, and known components can be used. Furthermore, the positive electrode binder of the present invention may contain solvents other than NMP, to the extent that they do not impair the properties of the present invention. These other components may be used individually or in combination of two or more types.

[0211] The solid content concentration of the positive electrode binder of the present invention is not particularly limited, but is usually in the range of 0.1 to 40% by mass, preferably 0.5 to 20% by mass, and more preferably 1 to 10% by mass.

[0212] The mixing method for hydrogenated nitrile rubber, NMP, and other components used as needed should follow conventional methods.

[0213] <Conductive material dispersion> The conductive material dispersion of the present invention is obtained by dissolving or dispersing the hydrogenated nitrile rubber and the conductive material in NMP. The conductive material dispersion of the present invention can be manufactured, for example, by mixing the positive electrode binder and the conductive material of the present invention.

[0214] (Conductive material) The conductive material is a component that functions to ensure electrical contact between electrode active materials. Carbonaceous materials can be suitably used as the conductive material. Examples of such carbonaceous materials include carbon black (e.g., acetylene black, Ketjenblack®, furnace black, etc.), single-walled or multi-walled carbon nanotubes (multi-walled carbon nanotubes include cup-stacked types), carbon nanohorns, vapor-grown carbon fibers, milled carbon fibers obtained by crushing polymer fibers after firing, single-walled or multi-walled graphene, and carbon nonwoven fabric sheets obtained by firing nonwoven fabrics made of polymer fibers. These may be used individually or in combination of two or more in any ratio. Among these, carbon nanotubes (CNTs) are preferred from the viewpoint of forming good conductive paths.

[0215] When mixing the positive electrode binder and the conductive material of the present invention, the ratio of the conductive material to the positive electrode binder is not particularly limited. For example, the resulting conductive material dispersion may contain hydrogenated nitrile rubber in an amount of 1 to 100 parts by mass, preferably 5 to 50 parts by mass, and more preferably 10 to 30 parts by mass, per 100 parts by mass of conductive material. Furthermore, when mixing the positive electrode binder and the conductive material, NMP can be added as needed to adjust the viscosity.

[0216] The solid content concentration when the positive electrode binder and conductive material of the present invention are mixed is usually 0.01% by mass or more, preferably 1.0% by mass or more, and more preferably 3.0% by mass or more, with an upper limit of usually 10.0% by mass or less, preferably 9.0% by mass or less, and more preferably 8.0% by mass or less. If the solid content concentration is above the lower limit, the coating properties of the conductive material dispersion can be improved. Furthermore, if the solid content concentration is below the upper limit, the rate characteristics of the resulting electrochemical element can be improved.

[0217] The method for mixing the positive electrode binder and conductive material of the present invention is not particularly limited, and can be used, for example, with known mixing equipment.

[0218] < Slurry for positive electrode > The slurry for the positive electrode of the present invention is obtained by dispersing or dissolving a positive electrode active material, a conductive material, and the hydrogenated nitrile rubber in N-methylpyrrolidone (NMP). Such a slurry for the positive electrode can be prepared by mixing the binder for the positive electrode and the conductive material with a solvent added as needed and then mixing the positive electrode active material.

[0219] <Electrodes for electrochemical elements> The positive electrode of the present invention comprises the hydrogenated nitrile rubber, and is composed of a positive electrode composite layer containing a binder containing the hydrogenated nitrile rubber, a conductive material, and a positive electrode active material, and a current collector. The positive electrode of the present invention can be manufactured by applying the above slurry for the positive electrode, in which the binder for the positive electrode and the conductive material are mixed with a solvent added as needed and then the positive electrode active material is mixed, onto the current collector and then drying it.

[0220] (Positive electrode active material) The positive electrode active material is not particularly limited. When the electrochemical element is a lithium ion secondary battery, examples include metal oxides containing lithium (Li). And as the positive electrode active material, a positive electrode active material containing at least one selected from the group consisting of cobalt (Co), nickel (Ni), manganese (Mn), and iron (Fe) in addition to lithium (Li) is preferred. Examples of such positive electrode active materials include lithium-containing cobalt oxide (LiCoO2), lithium manganate (LiMn2O4), lithium-containing nickel oxide (LiNiO2), lithium-containing composite oxides of Co-Ni-Mn, lithium-containing composite oxides of Ni-Mn-Al, lithium-containing composite oxides of Ni-Co-Al, olivine-type lithium manganese phosphate (LiMnPO4), olivine-type lithium iron phosphate (LiFePO4), lithium 1+x Mn 2-x excess spinel compounds represented by O4 (0 < X < 2), Li[Ni 0.17 Li 0.2 Co 0.07 Mn 0.56 O2, LiNi 0.5 Mn 1.5 O4, Li[Ni 0.5 Co 0.2 Mn 0.3Examples include O2. The particle size of the positive electrode active material is not particularly limited and can be the same as that of the electrode active materials conventionally used. The positive electrode active material may be used alone or in combination of two or more kinds at an arbitrary ratio.

[0221] The positive electrode active material can be mixed with the mixture of the binder for the positive electrode and the conductive material to form a slurry for the positive electrode. The mixing method is not particularly limited and can be carried out using a known mixing device. The amount of the positive electrode active material is not particularly limited and can be within the range conventionally used.

[0222] (Current collector) The current collector is made of a material having electrical conductivity and being electrochemically durable. The current collector is not particularly limited and known current collectors can be used. body For example, as the current collector provided in the positive electrode of a lithium-ion secondary battery, a current collector made of aluminum or an aluminum alloy can be used. At this time, aluminum and an aluminum alloy may be used in combination, or different aluminum alloys may be used in combination. Aluminum and aluminum alloys have heat resistance and are electrochemically stable, so they are excellent current collector materials. phase

[0223] The positive electrode of the present invention can be manufactured by applying the slurry for the positive electrode of the present invention described above to at least one surface of the current collector and drying to form a positive electrode composite layer.

[0224] (Coating process) The method for applying the slurry for the positive electrode onto the current collector is not particularly limited and a known method can be used. Specifically, as the coating method, a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating method, etc. can be used. At this time, the slurry for the positive electrode may be applied only to one side of the current collector or to both sides. The thickness of the slurry film on the current collector before drying after coating can be appropriately set according to the thickness of the positive electrode composite layer obtained after drying.

[0225] (drying process) The method for drying the positive electrode composite layer slurry on the current collector is not particularly limited and known methods can be used, such as drying with hot air, hot air, low-humidity air, vacuum drying, and drying by irradiation with infrared rays or electron beams. By drying the positive electrode composite layer slurry on the current collector in this way, a positive electrode composite layer is formed on the current collector, and a positive electrode comprising the current collector and the positive electrode composite layer can be obtained.

[0226] Furthermore, after the drying process, the electrode composite layer may be subjected to pressure treatment using a die press or roll press. Pressure treatment allows the positive electrode composite layer to adhere well to the current collector. In addition, if the positive electrode composite layer contains a curable polymer, the polymer may be cured after the formation of the positive electrode composite layer.

[0227] <Electrochemical elements> The electrochemical element of the present invention is characterized by containing the hydrogenated nitrile rubber of the present invention. The electrochemical element comprising the positive electrode of the present invention as described above has excellent capacitance characteristics, resistance characteristics, cycle characteristics and high-temperature storage characteristics, and is particularly preferably a lithium-ion secondary battery.

[0228] Herein, the configuration of a lithium-ion secondary battery as an example of the electrochemical element of the present invention will be described. This lithium-ion secondary battery comprises a positive electrode, a negative electrode, an electrolyte, and a separator, and the positive electrode is the electrode of the present invention.

[0229] (Negative electrode) The negative electrode is not particularly limited and any known electrode can be used.

[0230] (electrolyte) Typically, an organic electrolyte is used, which is obtained by dissolving a supporting electrolyte in an organic solvent. For example, lithium salts are used as supporting electrolytes. Examples of lithium salts include LiPF6, LiAsF6, LiBF4, LiSbF6, LiAlCl4, LiClO4, CF3SO3Li, C4F9SO3Li, CF3COOLi, (CF3CO)2NLi, (CF3SO2)2NLi, and (C2F5SO2)NLi. Among these, LiPF6, LiClO4, and CF3SO3Li are preferred, with LiPF6 being particularly preferred, because they are easily soluble in the solvent and exhibit a high degree of dissociation. Note that one type of electrolyte may be used alone, or two or more types may be used in any ratio. Generally, the lithium ion conductivity tends to increase as the supporting electrolyte with a higher degree of dissociation is used, so the lithium ion conductivity can be adjusted by the type of supporting electrolyte.

[0231] The organic solvent used in the electrolyte is not particularly limited as long as it can dissolve the supporting electrolyte, but suitable examples include carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), and methyl ethyl carbonate (EMC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; and sulfur-containing compounds such as sulfolane and dimethyl sulfoxide. A mixture of these solvents may also be used. Among these, carbonates are preferred because they have a high dielectric constant and a wide stable potential range, and a mixture of ethylene carbonate and diethyl carbonate is even more preferred.

[0232] The concentration of the electrolyte in the electrolyte solution can be adjusted as appropriate, for example, from 0.5 to 15% by mass. and It is preferable to have a concentration of 2 to 13% by mass, and even more preferable to have a concentration of 5 to 10% by mass. In addition, known additives such as vinylene carbonate, fluoroethylene carbonate, and ethylmethyl sulfone may be added to the electrolyte.

[0233] (Separator) The separator is not particularly limited, and for example, those described in Japanese Patent Publication No. 2012-204303 can be used. Among these, a microporous membrane made of polyolefin resin (polyethylene, polypropylene, polybutene, polyvinyl chloride) is preferred because it allows for a thinner overall film thickness of the separator, thereby increasing the ratio of electrode active material in the lithium-ion secondary battery and thus increasing the capacity per unit volume.

[0234] (Manufacturing method for lithium-ion secondary batteries) A lithium-ion secondary battery according to the present invention can be manufactured, for example, by stacking a positive electrode and a negative electrode with a separator in between, winding or folding them as needed according to the battery shape, placing them in a battery container, injecting an electrolyte into the battery container, and sealing it. To prevent pressure rise inside the secondary battery, overcharge and discharge, etc., an overcurrent prevention element such as a fuse or PTC element, expanded metal, lead plates, etc. may be provided as needed. The shape of the secondary battery may be any of the following: coin type, button type, sheet type, cylindrical type, rectangular type, flat type, etc.

[0235] <Application> The hydrogenated nitrile rubber of the present invention can exhibit its functionality and be effectively utilized in any electrochemical element other than the lithium-ion secondary battery described above. Examples of usable devices include non-aqueous electrolyte batteries such as lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, magnesium-ion batteries, calcium-ion batteries, aluminum-ion batteries, lithium-sulfur batteries, and lithium-air batteries; inorganic solid electrolyte batteries such as sulfide-based solid electrolytes and oxide-based solid electrolytes; polymer solid electrolyte batteries such as polyethylene oxide-based batteries; and semi-solid batteries such as polymer gel electrolyte batteries in which electrolyte is impregnated into PVDF.

[0236] The hydrogenated nitrile rubber of the present invention can also be suitably used in organic electrolyte capacitors, aqueous electrolyte capacitors, and aqueous solution batteries. In fuel cells, it can be used in PEFC, SOFC, DMPC, etc., and in particular, it can be used as a carrier for redox catalysts in addition to imparting conductivity to electrodes.

[0237] The hydrogenated nitrile rubber of the present invention can also be used for applications other than electrochemical elements. Other uses include, for example, seals, hoses, conductive belts, cable sheaths, roller covers and shock-absorbing applications in the automotive field, stators, well seals and valve seals in the oil production field, and various parts in the aviation industry, electrical industry, mechanical engineering and shipbuilding.

[0238] <Device configuration of the nitrile rubber manufacturing system> Hereinafter, the device configuration of a nitrile rubber manufacturing system for manufacturing nitrile rubber according to the present invention will be described. FIG. 1 is a diagram showing an example of a nitrile rubber manufacturing system in an embodiment of the present invention.

[0239] In FIG. 1, the device configuration of the nitrile rubber manufacturing system in the embodiment of the present invention is schematically illustrated according to the manufacturing process. The nitrile rubber manufacturing system shown in FIG. 1 generally includes an emulsion polymerization device 10, a coagulation device 30, a washing device 50, and a squeezer 70.

[0240] (Emulsion polymerization device 10) The emulsion polymerization device 10 is configured to perform processes related to the emulsion polymerization step. As shown in FIG. 1, the emulsion polymerization device 10 has a polymerization tank 11 and a stirring device 12 for copolymerizing monomer components such as acrylonitrile monomer and 1,3-butadiene monomer. The emulsion polymerization device 10 may be any of batch type, semi-batch type, and continuous type, and may be any of a tank reactor and a tubular reactor.

[0241] The polymerization tank 11 is formed, for example, in a closed cylindrical shape so that it can store the emulsion polymerization liquid. The stirring device 12 is located inside the polymerization tank 11 and includes a stirring blade 13 which is a member that rotates around a predetermined axis, a motor 14 that rotates the stirring blade 13, and a drive control unit (not shown) that controls the rotational number and rotational speed of the stirring blade 13.

[0242] A predetermined amount of acrylonitrile and 1,3-butadiene and water are placed in the polymerization tank 11, and an emulsifier and molecular weight adjuster are added. section After adding polymerization auxiliary materials such as additives and performing a nitrogen purge to remove oxygen from the polymerization tank 11, the polymerization initiator is added while stirring to start the polymerization reaction.

[0243] The stirring device 12 is configured to rotate the stirring blades 13 at a predetermined rotational speed (stirring speed) inside the polymerization vessel 11, thereby enabling proper flow of the emulsion polymerization liquid. The stirring speed of the stirring blades 13, the shape and size of the stirring blades 13, the number of blades installed, etc., are determined as appropriate considering the reaction conditions, etc.

[0244] The temperature of the emulsion polymerization solution inside the polymerization vessel 11 affects the reaction rate, molecular weight distribution, and molecular structure. For example, the proportion of 1,2-bond units in the polymerization units of 1,3-butadiene increases as the temperature of the emulsion polymerization solution increases and decreases as the temperature of the emulsion polymerization solution decreases, so this can be controlled by appropriately controlling the temperature of the emulsion polymerization solution.

[0245] When a predetermined polymerization conversion rate is reached, a polymerization inhibitor is added to the polymerization tank 11 to stop the polymerization reaction. The polymerization inhibitor rate can be used to control the molecular weight, molecular weight distribution, and the proportion of 1,2-bonding units in the 1,3-butadiene polymerization units of the nitrile rubber produced, so it can be appropriately selected according to the required properties. After that, a process related to the addition of an anti-aging agent is carried out, and the anti-aging agent is added to the polymerization tank 11 after the polymerization reaction is completed. Subsequently, the latex in the polymerization tank 11 is transferred to the solidification tank 31 of the solidification device 30.

[0246] (Coagulation device 30) The solidification apparatus 30 is configured to perform processing related to the solidification process. As shown in Figure 1, the solidification apparatus 30 has a solidification tank 31 and a stirring device 32 for solidifying the latex transferred from the emulsion polymerization apparatus 10 and extracting crumb-shaped nitrile rubber (water-containing crumb).

[0247] The solidification tank 31 is formed, for example, in a closed cylindrical shape and is capable of storing a solidified liquid containing a coagulant (for example, calcium chloride). The stirring device 32 is located inside the solidification tank 31 and includes a stirring blade 33 which is a member that rotates around a predetermined axis, a motor 34 that rotates the stirring blade 33, and a drive control unit (not shown) that controls the rotational number and speed of the stirring blade 33.

[0248] In the coagulation apparatus 30, hydrated crumbs are generated by bringing the latex transferred from the emulsion polymerization apparatus 10 into contact with a coagulation solution containing a coagulant (e.g., calcium chloride). The method of contact between the latex and the coagulation solution is not particularly limited; for example, the latex may be added to the agitated coagulation solution, or the coagulation solution may be added to the agitated latex. In this embodiment, the coagulation apparatus 30 employs the method of adding the latex to the agitated coagulation solution. Adding the latex to the agitated coagulation solution concentrates the generated hydrated crumbs so that their shape and diameter are uniform, significantly improving the cleaning efficiency in the subsequent cleaning process.

[0249] The stirring device 32 is configured to rotate the stirring blades 33 at a predetermined rotational speed (stirring speed) within the solidification tank 31, thereby enabling proper flow of the solidified liquid. The stirring speed of the stirring blades 33, the shape and size of the stirring blades 33, and the number of blades installed are determined appropriately considering the reaction conditions, but it is preferable to configure the device to apply a strong shear force in order to generate smaller water-containing crumbs.

[0250] In the method of adding latex to a stirred solidifying solution, the solidifying solution and water (soft water) are filled into the solidifying tank 31 and stirred with the stirring blade 33, and the latex is added to the stirred solidifying solution. The latex that comes into contact with the solidifying solution solidifies and a water-containing crumb is formed.

[0251] The water-containing crumb generated in the solidification tank 31 is removed from the solidification tank 31 by overflowing it along with the solidification liquid and water-containing liquid. The water-containing crumb removed from the solidification tank 31 is transferred to the washing tank 51 of the washing device 50 via the dewatering machine 38.

[0252] As shown in Figure 1, a dewatering machine 38 is positioned between the solidification tank 31 and the washing tank 51. The dewatering machine 38 is configured to separate the water-containing crumb from the liquid (solidified liquid). A screen, wire mesh, electric sieve, etc., can be used for the dewatering machine 38.

[0253] (Cleaning device 50) The washing device 50 is configured to perform the processing related to the washing process. As shown in Figure 1, the washing device 50 has a washing tank 51 for receiving the water-containing crumb and washing water transferred from the solidification device 30, a stirring device 52, and a heating device 55.

[0254] The washing tank 51 is formed, for example, in a closed cylindrical shape and is capable of storing water-containing crumb and washing water. The stirring device 52 is located inside the washing tank 51 and includes a stirring blade 53 which is a member that rotates around a predetermined axis, a motor 54 that rotates the stirring blade 53, and a drive control unit (not shown) that controls the rotational number and speed of the stirring blade 53. The heating device 55 includes a heating unit 56 that heats the inside of the washing tank 51, and a temperature control unit (not shown) that controls the temperature inside the washing tank 51.

[0255] The agitator 52 is configured to rotate the agitator blades 53 at a predetermined rotational speed (agitation speed) within the washing tank 51, thereby washing the water-containing crumbs by appropriately circulating the water-containing crumbs and washing water. The agitation speed of the agitator blades 53, the shape and size of the agitator blades 53, and the number of blades installed are determined appropriately considering the size of the water-containing crumbs and the washing efficiency.

[0256] The heating unit 56 of the heating device 55 sends steam to a jacket provided on the outer circumference of the washing tank 51, for example, and heats the washing liquid through heat exchange with the steam. The temperature of the washing water in the washing tank 51 is controlled to be, for example, 40°C or higher in order to improve the effect of releasing emulsifiers and coagulants from the water-containing crumb.

[0257] The water-containing crumb, washed in the washing tank 51, is removed from the washing tank 51 by overflowing with washing water. The water-containing crumb removed from the washing tank 51 is then transferred to the squeezer 70 via the dewatering machine 58.

[0258] (Squeezer 70) The squeezer 70 is configured to perform the dewatering process. In this embodiment, the squeezer 70 is used as the dewatering machine, but as a dewatering device for dewatering the water-containing crumb, for example, a screw-type twin-screw extruder dryer that performs dewatering and drying can be used.

[0259] As shown in Figure 1, the squeezer 70 has a two-stage configuration in which the upstream heating mechanism 71 and the downstream pressurizing mechanism 72 are connected by a connecting part 73.

[0260] The heating mechanism 71 includes a chamber 71a and a roller 71b for heating the water-containing cramb, a motor (not shown) that generates rotational power to rotate the roller 71b, and a heating device 71c that supplies steam into the chamber 71a. The roller 71b is housed in the chamber 71a so as to extend in the direction of conveying the water-containing cramb. The shape of the roller 71b is not particularly limited, but for example, it is formed in a screw shape.

[0261] At the upstream end of the chamber 71a, a crumb supply unit 70a is provided for introducing water-containing crumbs transferred from the washing device 50 into the chamber 71a. The downstream end of the chamber 71a is connected to a connecting unit 73. Steam at a predetermined temperature and pressure is supplied into the chamber 71a by a heating device 71c. The steam temperature is set to, for example, 120°C. The steam pressure is set to, for example, 150kPa. By heating the water-containing crumbs with steam in the heating mechanism 71, the dewatering efficiency in the subsequent pressurizing mechanism 72 can be improved.

[0262] The water-containing cramb fed into the cramb supply section 70a is heated while being pushed downstream by the rotation of the roller 71b (roller transport), and then transferred through the connecting section 73 into the chamber 72a of the pressurizing mechanism 72.

[0263] The pressurizing mechanism 72 includes a chamber 72a and a roller 72b for pressurizing the water-containing cramb, and a motor (not shown) that generates rotational power to rotate the roller 72b. The roller 72b is housed in the chamber 72a so as to extend in the direction of conveying the water-containing cramb. The shape of the roller 72b is not particularly limited, but for example, it is formed in a screw shape.

[0264] The upstream end of chamber 72a is connected to a connecting section 73. The downstream end of chamber 72a is provided with a crumb discharge section 70b for discharging the water-containing crumb that has been dewatered in chamber 72a.

[0265] The pressurizing mechanism 72 is configured such that a roller 72b compresses the water-containing crumb within the chamber 72a, squeezing out the moisture from the crumb. The roller 72b may be single or there may be two or more. The water-containing crumb is pushed downstream as moisture is squeezed out by the pressurizing effect of the rotation of the roller 72b, and is discharged from the crumb discharge section 70b. The dewatered water-containing crumb, dewatered by the squeezer 70, is transferred to the crushing device 75. The water content of the dewatered water-containing crumb is usually 35% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0266] (Crushing device 75) The crushing device 75 is configured to crush and pulverize the water-containing crumb transferred from the squeezer 70. The water-containing crumb discharged by the squeezer 70 after dewatering is uneven in size and shape. By crushing and pulverizing it in the crushing device 75, the drying efficiency in the subsequent drying process can be improved.

[0267] The crushing device 75 can be any device capable of crushing and pulverizing the crumb, such as a hammer-type crusher, cutter-type crusher, roller-type crusher, or pin mill. In particular, considering that it can efficiently and continuously crush water-containing crumb that has elasticity and viscosity, it is preferable to use a hammer-type crusher that crushes and pulverizes the water-containing crumb by the impact of a hammer rotated at high speed.

[0268] The water-containing crumb, crushed after dehydration, is dried in a drying process to become dried rubber. This dried rubber can be used, for example, as a bale of nitrile rubber in the production of hydrogenated nitrile rubber.

[0269] <Equipment configuration of the hydrogenated nitrile rubber manufacturing system> The following describes the apparatus configuration of the hydrogenated nitrile rubber manufacturing system according to the present invention. Figures 2 and 3 show an example of the hydrogenated nitrile rubber manufacturing system in an embodiment of the present invention.

[0270] Figures 2 and 3 schematically illustrate the apparatus configuration of a hydrogenated nitrile rubber manufacturing system according to an embodiment of the present invention, in accordance with the manufacturing process. The hydrogenated nitrile rubber manufacturing system shown in Figures 2 and 3 is generally configured to include a crushing device 110, a dissolving device 120, a hydrogenation reactor 130, a solidification device 150, a screw-type twin-screw extruder dryer 160, a cooling device 170, a cutting device 180, and a packaging device 190.

[0271] (Crushing device 110) The crushing device 110 is configured to process nitrile rubber (dried rubber), which is the raw material for hydrogenated nitrile rubber, into a size suitable for subsequent processing. 。

[0272] The nitrile rubber used as a raw material for hydrogenated nitrile rubber is nitrile rubber manufactured using the nitrile rubber manufacturing system described above. For example, nitrile rubber bales (dried rubber bales) in which nitrile rubber is baled are used.

[0273] The crushing device 110 can be any device capable of cutting the nitrile rubber bale to a predetermined size, for example, an extruder-equipped cutter and a crusher can be used. Specifically, the nitrile rubber bale is set in the extruder-equipped cutter. The nitrile rubber bale is extruded through a die to form a specific shape (rod-shaped, sheet-shaped, tube-shaped, etc.), and then cut off at the exit of the die by a cutter, and further crushed into smaller pieces using a crusher. The raw nitrile rubber (base rubber) obtained by crushing with the crushing device 110 is transferred to the dissolution device 120 by a conveyor 111.

[0274] (melting device 120) The dissolution apparatus 120 is configured to perform the dissolution process. As shown in Figure 2, the dissolution apparatus 120 includes a dissolution tank 121 for dissolving the base rubber in an organic solvent, a stirring device 122, and a heating device 125.

[0275] The dissolution tank 121 is formed, for example, in a closed cylindrical shape and is capable of storing the base rubber and organic solvent. The stirring device 122 includes a stirring blade 123 which is a component that rotates around a predetermined axis and is located inside the dissolution tank 121, a motor 124 that rotates the stirring blade 123, and a drive control unit (not shown) that controls the rotational speed and rotational number of the stirring blade 123. The heating device 125 includes a heating device 126 that heats the inside of the dissolution tank 121, and a temperature control unit (not shown) that controls the temperature inside the dissolution tank 121.

[0276] The stirring device 122 is configured to rotate the stirring blades 123 at a predetermined rotational speed (stirring speed) within the dissolution tank 121, thereby dissolving the base rubber in the organic solvent by appropriately flowing the base rubber and organic solvent. The stirring speed of the stirring blades 123, the shape and size of the stirring blades 123, the number of blades installed, etc., are determined appropriately considering the dissolution efficiency of the base rubber, etc.

[0277] The heating equipment 126 of the heating device 125 is configured to send a heat transfer medium to a jacket provided on the outer circumference of the dissolution tank 121, for example, and heat the dissolution liquid inside the dissolution tank 121 through heat exchange.

[0278] In the dissolution apparatus 120, a predetermined amount of base rubber and organic solvent are placed in the dissolution tank 121, and the base rubber is dissolved by properly stirring with the stirring blade 123 for a predetermined time or longer (for example, 2 hours or more). This yields a solution in which the base rubber is dissolved in the organic solvent. The solution obtained from the dissolution apparatus 120 is transferred to the hydrogenation reactor 130.

[0279] (Hydrogenation reactor 130) The hydrogenation reactor 130 is configured to perform the processes related to the hydrogenation step. As shown in Figure 2, the hydrogenation reactor 130 has a reaction tank (hydrogenation reaction tank) 131 for bringing nitrile rubber dissolved in an organic solvent into contact with hydrogen for the hydrogenation reaction, a stirring device 132, and a heating device 135.

[0280] The reaction tank 131 is formed, for example, in a closed cylindrical shape and is capable of storing the dissolved solution transferred from the dissolution tank 121. The reaction tank 131 can also receive hydrogen from a hydrogen supply source 137 into the gas phase and a catalyst for the hydrogenation reaction from a catalyst supply source 138. The stirring device 132 is located inside the reaction tank 131 and includes a stirring blade 133 which rotates around a predetermined axis, a motor 134 which rotates the stirring blade 133, and a drive control unit (not shown) which controls the rotational speed and rotational number of the stirring blade 133. The heating device 135 includes a heating device 136 which heats the inside of the reaction tank 131 and a temperature control unit (not shown) which controls the temperature inside the reaction tank 131.

[0281] The stirring device 132 is configured to rotate the stirring blades 133 at a predetermined rotational speed (stirring speed) within the reaction tank 131, thereby appropriately flowing the dissolution and bringing it into contact with and reacting with hydrogen in the gas phase. The stirring speed of the stirring blades 133, the shape and size of the stirring blades 133, the number of blades installed, etc., are determined appropriately considering the reaction efficiency, etc. For example, multiple stirring blades 133 may be placed at different height positions, in which case it is preferable that one of the stirring blades 133 is placed at a position that shears the gas-liquid interface between the hydrogen in the gas phase and the dissolution in the liquid phase within the reaction tank 131.

[0282] The heating equipment 136 of the heating device 135 is configured to send a heat transfer medium to a jacket provided on the outer circumference of, for example, the reaction tank 131, and heat the solubility in the corresponding reaction tank 131 through heat exchange. The temperature inside the reaction tank 131 is preferably set to a temperature at which the hydrogenation reaction is effectively promoted, for example, to 150°C.

[0283] In the hydrogenation reactor 130, a solution of nitrile rubber dissolved in an organic solvent is placed in the reaction tank 131, a catalyst is added, and hydrogen is supplied until a predetermined pressure is reached, bringing the solution into contact with hydrogen to hydrogenate the nitrile rubber. The catalyst used selectively hydrogenates only the carbon double bonds in the 1,3-butadiene polymerization units of the nitrile rubber polymer. Since the hydrogenation reaction takes place at the gas-liquid interface where gaseous hydrogen and liquid-phase solution come into contact, the hydrogenation reaction can be accelerated by, for example, using a stirring blade 133 to flow the solution vertically, thereby refreshing the solution in contact with the gas phase and shearing the gas-liquid interface.

[0284] (Coagulation device 150) The solidification device 150 is configured to perform the processing related to the solidification process. The solidification device 150 replaces the organic solvent in the solution with soft water (solidification solution), which is a polar solvent, to solidify the hydrogenated nitrile rubber into a crumb-like form. In this embodiment, in order to efficiently solidify the hydrogenated nitrile rubber, the solidification device 150 has first and second solidification tanks 151a and 151b. As shown in Figure 3, the two solidification tanks, the first and second solidification tanks 151a and 151b, are connected in series, but the number of solidification tanks and the connection configuration are not particularly limited.

[0285] The first and second solidification tanks 151a and 151b are equipped with stirring devices 152a and 152b and a heating device 155a.

[0286] The stirring devices 152a and 152b are arranged inside each solidification tank and include stirring blades 153a and 153b, which are members that rotate around a predetermined axis, motors 154a and 154b that rotate the stirring blades 153a and 153b, and a drive control unit (not shown) that controls the rotational speed and rotational number of the stirring blades 153a and 153b. The heating device 155a includes a heating unit 156a that heats the inside of the first solidification tank 151a, and a temperature control unit (not shown) that controls the temperature inside the first solidification tank 151a. Here, the heating device 155a is installed in the first solidification tank 151a for heating, but the second solidification tank 151b may be heated in the same way.

[0287] The solidification apparatus 150 is configured to rotate the stirring blades 153a and 153b at a predetermined rotational speed (stirring speed) within the first and second solidification tanks 151a and 151b, thereby enabling proper flow of the fluid contained within the first and second solidification tanks 151a and 151b. The stirring speed of the stirring blades 153a and 153b, the shape and size of the stirring blades 153a and 153b, the number of blades installed, etc., are determined appropriately considering the reaction conditions, etc.

[0288] The fluids in the first and second solidification tanks 151a and 151b are transported sequentially from upstream to downstream by pumps 157a and 157b as a cramb-containing fluid containing cramb-shaped solidified hydrogenated nitrile rubber and solidification liquid. Pump 157a transports the liquid from the first solidification tank 151a to the second solidification tank 151b. Pump 157b transports the liquid from the second solidification tank 151b to the screw-type twin-screw extruder dryer 160 via a dewatering machine 158. The transport by pumps 157a and 157b is controlled by a pump drive control unit (not shown).

[0289] The dissolved solution transferred from the hydrogenation reactor 130 to the solidification reactor 150 is continuously supplied into the first solidification tank 151a. Steam and water (soft water) are supplied to the first solidification tank 151a. The temperature of the steam and water is adjusted so that the temperature inside the first solidification tank 151a is above the boiling point of the organic solvent. As the dissolved solution is stirred in the first solidification tank 151a, the organic solvent vaporizes (evaporates) and is replaced by highly polar water, causing the hydrogenated nitrile rubber in the organic solvent to precipitate.

[0290] Similarly, in the second solidification tank 151b, stirring the liquid inside the second solidification tank 151b promotes the vaporization of the organic solvent, causing hydrogenated nitrile rubber to precipitate from the organic solvent. The liquid discharged from the second solidification tank 151b is in the form of a crumb-containing slurry, in which the organic solvent has vaporized and crumb-shaped hydrogenated nitrile rubber is suspended in the liquid (water).

[0291] The solidification apparatus 150 is designed to precipitate and solidify the hydrogenated nitrile rubber dissolved in the solution as a solid by stirring the solution in an environment above the boiling point of the organic solvent, vaporizing the organic solvent, and replacing it with water, in which the hydrogenated nitrile rubber is insoluble.

[0292] As shown in Figure 3, a dewatering machine 158 is positioned between the solidification device 150 and the screw-type twin-screw extruder dryer 160. The dewatering machine 158 is configured to separate the water-containing crumb from the slurry. A screen, wire mesh, electric sieve, etc., can be used for the dewatering machine 158.

[0293] (Screw-type twin-screw extruder dryer 160) The screw-type twin-screw extruder dryer 160 is configured to perform processes related to the dewatering and drying process. The screw-type twin-screw extruder dryer 160 dewaters and dries the water-containing crumb, and also molds the dried hydrogenated nitrile rubber into a predetermined shape and discharges it, and is configured to perform processes related to part of the molding process.

[0294] Although the screw-type twin-screw extruder dryer 160 is designed to perform the dewatering and drying processes continuously, the dewatering and drying processes may be performed using different devices. For example, a squeezer may be used as the dewatering machine for the dewatering process, and a hot air dryer, vacuum dryer, expander dryer, kneader dryer, etc. may be used as the dryer for the drying process.

[0295] The screw-type twin-screw extruder dryer 160 in this embodiment has a barrel unit that dewaters and dries hydrogenated nitrile rubber while conveying it. The barrel unit has a supply barrel section 161 that supplies water-containing crumb into the barrel unit from the upstream side to the downstream side, a dewatering barrel section 162 that functions as a dewaterer, and a drying barrel section 163 that functions as a dryer. Furthermore, a die section 164 is provided at the downstream end of the barrel unit that molds the hydrogenated nitrile rubber into a predetermined shape and discharges it.

[0296] The supply barrel section 161, the dewatering barrel section 162, and the drying barrel section 163 may each be configured by connecting multiple barrels. That is, the barrel unit may be composed of multiple barrels connected from the upstream side to the downstream side. The number of barrels that make up the supply barrel section 161, the dewatering barrel section 162, and the drying barrel section 163 is not particularly limited and can be set to a number according to the water content of the hydrogenated nitrile rubber, etc.

[0297] The supply barrel section 161 is the region that supplies the water-containing crumb, which has been transferred from the solidification device 150 via the dewatering machine 158, into the barrel unit. The barrels constituting the supply barrel section 161 have feed ports that supply the water-containing crumb into the barrel unit.

[0298] The dewatering barrel section 162 is a region that separates and discharges moisture (ceramic water) from the hydrogenated nitrile rubber. In the dewatering barrel section 162, the moisture contained in the hydrogenated nitrile rubber is discharged in liquid form (wastewater) and vapor form (exhaust steam). The barrels constituting the dewatering barrel section 162 have dewatering slits that discharge the moisture contained in the hydrogenated nitrile rubber to the outside as wastewater or exhaust steam. Which dewatering barrel discharges the moisture as wastewater or exhaust steam can be set as appropriate.

[0299] The drying barrel section 163 is a region where the hydrogenated nitrile rubber, after dewatering in the dewatering barrel section 162, is dried under reduced pressure. The barrels constituting the drying barrel section 163 have vent ports for degassing. Vent piping is connected to each vent port, and a vacuum pump is connected to the vent piping. The operation of the vacuum pump reduces the pressure inside the drying barrel section 163 to a predetermined level. The degree of pressure reduction in the drying barrel section 163 is appropriately controlled by the pressure control unit. The hydrogenated nitrile rubber is melted and kneaded under reduced pressure in the drying barrel section, thereby removing any air it contains.

[0300] The die section 164 is a processing mold section located at the downstream end of the barrel unit and has an outlet with a predetermined nozzle shape. The hydrogenated nitrile rubber, dried via the drying barrel section 163, passes through the outlet of the die section 164 and is extruded into a shape corresponding to the predetermined nozzle shape. The hydrogenated nitrile rubber passing through the die section 164 can be molded into various shapes such as granular, columnar, round rod, or sheet, depending on the nozzle shape of the die section 164. In this embodiment, the nozzle shape of the die section 164 is formed in a horizontally elongated, approximately rectangular shape, and the hydrogenated nitrile rubber passing through the die section 164 is molded into a sheet. The sheet-shaped hydrogenated nitrile rubber is molded to a width of approximately 20 to 60 cm and a height of approximately 2 to 10 cm and extruded from the die section 164. A breaker plate or wire mesh may also be provided between the tip of the screw and the die section 164.

[0301] The barrels constituting the dewatering barrel section 162 and the barrels constituting the drying barrel section 163 are heated. The heating method is not particularly limited, but it is preferable, for example, to supply high-temperature steam from a steam supply means to the steam flow jacket formed in each barrel. Each barrel may be heated at a different set temperature, or at the same set temperature. The hydrogenated nitrile rubber extruded and conveyed downstream by the screw becomes under high pressure and at a high temperature downstream. The temperature of the hydrogenated nitrile rubber discharged from the die section 164 is, for example, about 200°C.

[0302] The screw-type twin-screw extruder dryer 160 has a pair of screws inside the barrel unit. The pair of screws extends from the upstream side to the downstream side inside the barrel unit. The pair of screws are rotationally driven by a screw drive unit 165 such as a motor. This allows the water-containing crumb supplied from the feed port to the supply barrel section 161 to be conveyed downstream while being mixed. As the screws rotate, the water-containing crumb is plasticized and mixed to become a molten mixture (molten compound), which is then conveyed downstream while being dewatered and dried, and discharged from the die section 164.

[0303] Preferably, the pair of screws are of the biaxial meshing type, where the peaks and valleys of each screw mesh with each other, thereby improving the dewatering and drying efficiency of hydrogenated nitrile rubber. The pair of screws may rotate in the same direction or in different directions, but it is preferable to rotate them in the same direction to take into consideration the self-cleaning performance.

[0304] The screw shape (flight shape) of the pair of screws is not particularly limited, but it is preferable to select a shape that can effectively bring out the function of each barrel. For example, to promote heat generation by shear, shapes such as half-angle flights or forward flights may be used. In addition, kneading discs with cross-sectional shapes such as pseudo-elliptical, oval, or truncated triangular shapes may be provided in the regions corresponding to the dewatering barrel section 162 and the drying barrel section 163.

[0305] The water-containing crumb, transferred from the coagulation device 150 via the dewatering machine 158, is supplied to the supply barrel section 161 through the feed port. The hydrogenated nitrile rubber supplied to the supply barrel section 161 is sent from the supply barrel section 161 to the dewatering barrel section 162 by the rotation of a pair of screws located within the barrel unit. In the dewatering barrel section 162, water is squeezed out of the molten hydrogenated nitrile rubber and discharged as wastewater or exhaust steam.

[0306] The hydrogenated nitrile rubber, dewatered in the dewatering barrel section 162, is sent from the dewatering barrel section 162 to the drying barrel section 163 by the rotation of a pair of screws in the barrel unit. The molten hydrogenated nitrile rubber is carried downstream in the drying barrel section 163, generating heat and increasing in temperature. In the drying barrel section 163, the water contained in the molten hydrogenated nitrile rubber vaporizes, and this water is discharged to the outside as exhaust steam through a vent pipe connected to a vent port. After passing through the drying barrel section 163, the hydrogenated nitrile rubber becomes a dry molten material, which is supplied to the die section 164 by the rotation of a pair of screws in the barrel unit, and extruded from the die section 164 into a predetermined shape (e.g., a sheet).

[0307] The operating conditions of the screw-type twin-screw extruder dryer 160 can be appropriately selected according to the characteristics of the hydrogenated nitrile rubber being manufactured. Examples of operating conditions for the screw-type twin-screw extruder dryer 160 include the screw rotation speed (N) and extrusion rate (Q), the ratio of extrusion rate (Q) to rotation speed (N) (Q / N), the screw's maximum torque, specific power, specific power, shear rate, etc.

[0308] The sheet-like hydrogenated nitrile rubber discharged from the die section 164 of the screw-type twin-screw extruder dryer 160 at a predetermined extrusion speed is conveyed to the cooling device 170 in a continuous strip-like state in the discharge direction. The water content of the hydrogenated nitrile rubber dried in the screw-type twin-screw extruder dryer 160 is less than 1% by weight.

[0309] The sheet-like hydrogenated nitrile rubber extruded from the die section 164 of the screw-type twin-screw extruder dryer 160 is transported in a continuous strip-like form from the die section 164 of the screw-type twin-screw extruder dryer 160 through the cooling device 170 to the cutting device 180.

[0310] (Cooling device 170) The cooling device 170 is configured to perform the cooling process. Cooling methods for the cooling device 170 include water cooling, such as spraying cooling water or immersing in water; air cooling, such as blowing cooling air; and leaving it at room temperature. In this embodiment, the cooling device 170 has a shower device 171 that sprays cooling water onto the sheet-shaped hydrogenated nitrile rubber, and a transport-type cooling device 173 that blows cooling air while transporting the sheet-shaped hydrogenated nitrile rubber. By drying in the order of water cooling followed by air cooling, it is preferable to obtain sheet-shaped hydrogenated nitrile rubber with a water content of less than 1% by mass in a short time.

[0311] The shower device 171 is positioned close to the die section 164 of the screw-type twin-screw extruder dryer 160 and is configured to cool the sheet-shaped hydrogenated nitrile rubber immediately after it is discharged from the die section 164 by spraying it with cooling water in a shower-like manner. The sheet-shaped hydrogenated nitrile rubber, to which the cooling water has been sprayed, is transported to a transport-type cooling device 173 by a roller conveyor 172 (not shown in detail) having transport rollers. The roller conveyor 172 may be, for example, a tubular cooling transport pipe formed to cool the sheet-shaped hydrogenated nitrile rubber.

[0312] As shown in Figure 3, the conveyor-type cooling device 173 has a configuration in which a conveyor 174 for conveying sheet-shaped hydrogenated nitrile rubber and a cooling means 175 for sending out cooling air are arranged in an air cooling tank 176. The device is configured to cool the sheet-shaped hydrogenated nitrile rubber by blowing cooling air from the cooling means 175 while it is being conveyed by the conveyor 174. The sheet-shaped hydrogenated nitrile rubber cooled in the conveyor-type cooling device 173 is then conveyed to a cutting device 180 located downstream.

[0313] The conveying surface of the conveyor belt 174 is made of a non-adhesive material that prevents the sheet-like hydrogenated nitrile rubber from sticking. In addition, a horizontal air duct 177 may be provided at least one end of the conveyor belt 174 to supply cooling air into the air cooling tank 176.

[0314] The conveying speed of the sheet-shaped hydrogenated nitrile rubber by the conveyor belt 174 is approximately the same as the discharge speed of the sheet-shaped hydrogenated nitrile rubber discharged from the die section 164 of the screw-type twin-screw extruder dryer 160. The length of the conveyor belt 174, the length of the cooling means 175 (the area to which cooling air is blown), and the cooling time (cooling speed) are appropriately set according to the target cooling temperature of the sheet-shaped hydrogenated nitrile rubber discharged from the conveyor-type cooling device 173. The target cooling temperature is set to, for example, 40°C or lower, which makes it possible to easily and stably cut the sheet-shaped hydrogenated nitrile rubber in a subsequent stage.

[0315] The conveying cooling device 173 may be configured to convey sheet-shaped hydrogenated nitrile rubber by folding it back and forth on a multi-stage conveyor with multiple rollers or rod-shaped slats. In this case, the sheet-shaped hydrogenated nitrile rubber discharged from the die section 164 of the screw-type twin-screw extruder dryer 160 is conveyed by descending one stage at a time from the top stage of the conveyor constituting the conveying conveyor 174. Cooling air is blown onto each stage of the conveyor from the upper side (the upper surface side of the sheet-shaped hydrogenated nitrile rubber).

[0316] When the conveyor belt 174 is configured with multiple upper and lower conveyors and the material is transported in a folded manner, the sheet-like hydrogenated nitrile rubber can be transported with each stage inverted. By blowing cooling air onto each stage conveyor from the upper side (top side), both sides of the sheet-like hydrogenated nitrile rubber can be cooled uniformly and reliably. In addition, each folded section can be made into a free-shrinking section, allowing the sheet-like hydrogenated nitrile rubber to shrink with ample margin in that free-shrinking section.

[0317] (Cutting device 180) The sheet-shaped hydrogenated nitrile rubber is connected in a strip-like manner from the die section 164 of the screw-type twin-screw extruder dryer 160 through the conveying cooling device 173 to the cutting device 180. The cutting device 180 is configured to cut the sheet-shaped hydrogenated nitrile rubber to process it into cut sheet-shaped hydrogenated nitrile rubber, and includes a clamper 181 that supports the leading edge of the sheet-shaped hydrogenated nitrile rubber, and a cutter 182 that is vertically movable on the upper surface of the sheet-shaped hydrogenated nitrile rubber. The cutting blade of the cutter 182 is positioned approximately perpendicular to the upper surface of the sheet-shaped hydrogenated nitrile rubber.

[0318] The leading edge of the sheet-like hydrogenated nitrile rubber that reaches the cutting table of the cutting device 180 is held stably by the clamper 181 and cut to a predetermined length by the cutter 182 to produce a cut sheet of hydrogenated nitrile rubber. The timing for raising and lowering the cutter 182 is controlled by a cutter control unit (not shown). The cutter control unit may raise and lower the cutter 182 by detecting the length (feed amount) of the sheet-like hydrogenated nitrile rubber conveyed onto the cutting table, or it may raise and lower the cutter 182 in synchronization with the conveying speed (feed speed) of the sheet-like hydrogenated nitrile rubber.

[0319] The cut sheets of hydrogenated nitrile rubber produced by the cutting device 180 are transported to the vicinity of the workbench 183, where they are stacked. The stacked cut sheets of hydrogenated nitrile rubber adhere to each other due to their own weight, becoming a single block (dry rubber bale) in the form of a mass (bale).

[0320] The cut sheet-like hydrogenated nitrile rubber on the workbench 183 is weighed by a weighing cell and adjusted to produce 25 kg dry rubber bales. The produced dry rubber bales are transferred to the packaging device 190 by a roller conveyor 185. [Examples]

[0321] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the following description, "%", "ppm", and "parts" used to express quantities refer to mass unless otherwise specified.

[0322] Furthermore, in polymers produced by copolymerizing multiple types of monomers, the proportion of a monomer unit formed by polymerizing a certain monomer in the polymer is, unless otherwise specified, usually equal to the ratio (starting ratio) of that particular monomer to the total monomers used in the polymerization of the polymer.

[0323] In the examples and comparative examples, various measurements and evaluations were carried out according to the following methods.

[0324] <Moisture-containing crumb diameter> The water-containing crumbs produced by the coagulation reaction were classified using a JIS classification sieve. Afterward, each classified water-containing crumb was dried in a hot air dryer at 80°C for 3 hours, and the mass was measured to determine the proportions of masses of each crumb diameter (a) to (h). The JIS sieve conformed to the specifications of the Japanese Industrial Standard (JIS Z 8801-1). (a) It does not pass through a JIS sieve with a mesh size of 9.5 mm. (b) It passes through a JIS sieve with a mesh size of 9.5 mm but does not pass through a JIS sieve with a mesh size of 8.0 mm. (c) It passes through a JIS sieve with a mesh size of 8.0 mm but does not pass through a JIS sieve with a mesh size of 4.75 mm. (d) It passes through a JIS sieve with a mesh size of 4.75 mm but does not pass through a JIS sieve with a mesh size of 3.35 mm. (e) It passes through a JIS sieve with a mesh size of 3.35 mm but does not pass through a JIS sieve with a mesh size of 2.36 mm. (f) It passes through a JIS sieve with a mesh size of 2.36 mm but does not pass through a JIS sieve with a mesh size of 1.7 mm. (g) It passes through a JIS sieve with a mesh size of 1.7 mm but does not pass through a JIS sieve with a mesh size of 0.43 mm. (h) It passes through a JIS sieve with a mesh size of 0.43 mm.

[0325] <Water content of moist crumb> The water content of the hydrated crumb produced by the coagulation reaction after dehydration was determined according to the "oven method" specified in JIS K6238-1. Specifically, 10 g of hydrated crumb was placed in an oven at 105 ± 5°C and dried until the mass no longer changed substantially. The mass loss before and after drying was determined, and the ratio of the mass loss to the mass of the dried crumb was calculated to determine the water content.

[0326] <Repeat Unit> The acrylonitrile polymerization units and 1,3-butadiene polymerization units (the sum of 1,2-bonding units, 1,4-bonding units, and their hydride units) in hydrogenated nitrile rubber are, 1The content ratio in the polymer was determined by obtaining the intensity ratio of the peaks derived from each repeating unit by H-NMR (nuclear magnetic resonance) method and converting it into a mass ratio.

[0327] The ratio of 1,2-bonded units in the 1,3-butadiene polymerization unit of hydrogenated nitrile rubber is 1 By H-NMR (nuclear magnetic resonance) method, the peak intensities derived from 1,2-bonded units, 1,4-bonded units and their hydrogenated units were obtained, and the ratio of (total amount of 1,2-bonded units and their hydrogenated units) / (total amount of 1,2-bonded units, 1,4-bonded units and their hydrogenated units) was calculated.

[0328] <Iodine value> The iodine value of hydrogenated nitrile rubber was measured according to JIS K 6235.

[0329] <THF molecular weight> The weight average molecular weight (Mw), Z average molecular weight (Mz), and molecular weight distribution (Mz / Mw) of hydrogenated nitrile rubber were measured by gel permeation chromatography (GPC) using a tetrahydrofuran (THF) solution under the following measurement conditions. · Separation column: TSK-gel SuperHM-H (manufactured by Tosoh Corporation) · Detector: Differential refractometer detector RID-10A (manufactured by Shimadzu Corporation) · Flow rate of eluent: 0.6 mL / min · Column temperature: 40 °C · Standard polymer: TSK standard polystyrene (manufactured by Tosoh Corporation)

[0330] <NMP molecular weight> The weight average molecular weight (Mw) of hydrogenated nitrile rubber was measured by gel permeation chromatography (GPC) using a NMP solution under the following measurement conditions. · Separation column: Shodex KD-806M (manufactured by Showa Denko KK) · Detector: Differential refractometer detector RID-10A (manufactured by Shimadzu Corporation) · Flow rate of eluent: 0.3 mL / min · Column temperature: 40 °C • Standard polymer: TSK standard polystyrene (manufactured by Tosoh Corporation)

[0331] <Polymer pH> To 10 g of NMP solution (solid content concentration: 8%) of hydrogenated nitrile rubber or hydrogenated nitrile rubber bale, 90 g of deionized water was added. The mixture was stirred and pressed with a spatula, and the liquid contained within the solidified hydrogenated nitrile rubber was extracted in the deionized water phase to obtain an extract. The pH of the extract was measured at 25°C in accordance with JIS Z8802 (2011).

[0332] <Anti-aging agent content> Hydrogenated nitrile rubber or hydrogenated nitrile rubber bales were dissolved in a chlorobenzene solution and analyzed by gas chromatography to determine the proportion of the antioxidant (BHT) based on the total mass of the polymer.

[0333] <Bulk density> Cut out pieces approximately 2cm x 3cm x 0.2cm from hydrogenated nitrile rubber or a bale of hydrogenated nitrile rubber, and measure the bulk density (g / cm³) using an automatic hydrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name: "DSG-1"). 3 ) was measured.

[0334] <Particle size distribution of polymer: D90 / D10, D50 / D10> Hydrogenated nitrile rubber or hydrogenated nitrile rubber bale was dissolved in N-methylpyrrolidone (NMP), then adjusted to a solid content concentration of 0.3%, and stirred at 60 rpm for at least 30 minutes until dissolution was confirmed to obtain an NMP solution for measurement. The obtained NMP solution was measured under 25°C using a dynamic light scattering analyzer (ELSZ-2000S, Otsuka Electronics Co., Ltd.) to determine the volume-based particle size distribution: particle size D10 when 10% of the total volume was present, particle size D50 (median diameter) when 50% was present, and D90 when 90% was present. D50 / D10 and D90 / D10 were then calculated.

[0335] <Water content of polymer> The water content of hydrogenated nitrile rubber and hydrogenated nitrile rubber bales was measured in accordance with the "oven method" specified in JIS K6238-1.

[0336] <Ash content> The ash content in hydrogenated nitrile rubber and hydrogenated nitrile rubber bales was measured in accordance with the JIS K6228A method.

[0337] <Ash content> The amounts of each component in the ash were determined by pressing the ash sample collected during the above ash content measurement onto a Φ20 mm titration filter paper and performing XRF measurement using a ZSXPrimus (manufactured by Rigaku).

[0338] <Long-term storage properties of positive electrode binders> The positive electrode binders obtained in the examples and comparative examples were stored at 25°C for 3 months, then 500 mL was passed through a 200-mesh wire mesh (wire diameter 0.05 mm) and dried at 105°C for 1 hour. The amount of aggregates (%) contained in the positive electrode binder was then calculated using the following formula. Aggregate amount (%) = (Mass of wire mesh after drying - Mass of wire mesh before sample passage) / (Mass of positive electrode binder × Solid content concentration of positive electrode binder (%) / 100) × 100 The calculated aggregate quantity was evaluated according to the following criteria. A lower aggregate quantity indicates superior agglomeration resistance of the cathode binder. ◎: Aggregate content is less than 0.05% ○: Aggregate content is 0.05% or more and less than 0.1% △: Aggregate content is 0.1% or more but less than 0.5% ×: Aggregate content is 0.5% or more

[0339] <Dispersibility of conductive material dispersion> The conductive material dispersions obtained in the examples and comparative examples were evaluated according to the following criteria. The viscosity was measured for 120 seconds at a temperature of 25°C and a shear rate of 10¹ / s using a rheometer (Anton Paar, "MCR302"). An index was calculated based on the average viscosity measurement from 61 seconds to 120 seconds, with Comparative Example 1 set to 100. A smaller index of the dispersion viscosity indicates better dispersibility. ◎: 85 or less 〇: More than 85 but less than 90 △:Over 90 but below 95 ×: Over 95

[0340] <Stability of viscosity of conductive material dispersion> The conductive material dispersions obtained in the examples and comparative examples were stored in a sealed container at 25°C for 10 days after measuring the viscosity of the dispersion (η0). The viscosity was then measured again (η1), and the viscosity change rate was calculated. The viscosity retention rate Δη = η1 / η0 × 100 (%) of the conductive material dispersion before and after storage was calculated, and an index was determined with Comparative Example 1 set to 100. The viscosity stability of the conductive material dispersion was then evaluated according to the following criteria. A smaller index of the viscosity retention rate Δη indicates superior viscosity stability of the conductive material dispersion. ◎: Less than 90 ○: 90 or higher, less than 94 △: 94 or higher and less than 98 ×: 98 or more and less than 110 ××: 110 or more

[0341] <Slurry viscosity stability> The viscosity τ0 of the obtained cathode slurry was measured using a Type B viscometer (Toki Sangyo Co., Ltd., product name "TVB-10", rotation speed: 60 rpm). Next, the cathode slurry whose viscosity was measured was stirred for 72 hours using a planetary mixer (rotation speed: 60 rpm), and the viscosity τ1 of the cathode slurry after stirring was measured using the same Type B viscometer (rotation speed: 60 rpm). The viscosity retention rate Δτ = τ1 / τ0 × 100 (%) of the cathode slurry before and after stirring was calculated, and the viscosity stability of the cathode slurry was evaluated according to the following criteria. The temperature during viscosity measurement was 25°C. The closer the viscosity retention rate Δη is to 100%, the better the viscosity stability of the slurry composition. ◎: Viscosity retention rate Δτ is 90% or more and less than 110% ○: Viscosity retention rate Δτ is 110% or more and less than 130% △: Viscosity retention rate Δτ is 130% or more but less than 150% ×: Viscosity maintenance rate Δτ is 150% or more

[0342] <Peel strength> The positive electrodes prepared in the examples and comparative examples were cut into rectangles measuring 100 mm in length and 10 mm in width to form test specimens. Cellophane tape (compliant with JIS Z1522) was attached to the surface of the positive electrode composite layer with the side containing the positive electrode composite layer facing downwards. The stress was measured when one end of the current collector was pulled vertically at a speed of 100 mm / min to peel off the tape (the cellophane tape was fixed to the test stand). Three measurements were taken, and an index was calculated based on the average value, with Comparative Example 3 set to 100. The results were then evaluated according to the following criteria. A higher peel strength index indicates that the positive electrode composite layer is more firmly adhered to the current collector made of aluminum foil. ◎: 150 or more 〇: 130 or more, less than 150 △: 110 or more and less than 130 ×: Less than 110

[0343] <Flexibility> The positive electrodes prepared in the examples and comparative examples were wrapped around a 2.5 mm diameter stainless steel cylinder (with the current collector facing inward). The presence or absence of crack formation on the surface of the positive electrode composite layer was visually inspected. If no crack formation was observed, the diameter of the stainless steel cylinder was sequentially reduced to 2.0 mm and then 1.5 mm, and the same procedure was repeated. The diameter of the cylinder at which the first crack was observed on the surface of the positive electrode composite layer (cylinder diameter at the time of crack formation) was recorded and evaluated according to the following criteria. A smaller cylinder diameter at the time of crack formation indicates superior flexibility of the positive electrode, and if no cracks are formed even when using a 1.5 mm diameter cylinder, it indicates extremely superior flexibility of the positive electrode. ◎: No crack formation was observed even with a cylinder diameter of 1.5 mm. ○: The diameter of the cylinder at the time of crack formation is 1.5 mm △: The diameter of the cylinder at the time of crack formation is 2.0 mm. ×: The cylindrical diameter at the time of crack formation is 2.5 mm.

[0344] <Warping characteristics> The positive electrodes prepared in the examples and comparative examples were cut into strips measuring 2 cm in width (coating width direction) and 5 cm in length (coating direction) to form test specimens. These test specimens were placed on a horizontal surface with the positive electrode composite layer side facing downwards. The height of the edges of the test specimens from the horizontal surface (amount of warping) when the center of the width direction of both ends of the length direction of the test specimen was pressed down from above against the horizontal surface was measured using a displacement laser (Keyence Corporation "LJV-7080"). An index was calculated with Comparative Example 2 set to 100, and evaluated according to the following criteria. A smaller index of warping indicates that the warping of the positive electrode is suppressed. ◎: 90 or less ○: More than 90 but less than 95 △: More than 95 and less than 100 ×: Over 100, or the positive electrode composite layer is cracked.

[0345] <Capacity Characteristics> The lithium-ion secondary batteries prepared in the examples and comparative examples were left to stand at 25°C for 5 hours after electrolyte injection. Next, they were charged to a cell voltage of 3.65V using a constant current method at 25°C and 0.2C (where C is a value expressed as rated capacity (mA) / 1h (hour)), and then aged at 60°C for 12 hours. Then, they were discharged to a cell voltage of 3.00V using a constant current method at 25°C and 0.2C. After that, CC-CV charging (upper limit cell voltage 4.35V) was performed using a constant current method at 0.2C, and CC discharge was performed to 3.00V using a constant current method at 0.2C. This 0.2C charge-discharge cycle was repeated three times. The discharge capacity of this third discharge was taken as the initial capacity, and the value of initial capacity / theoretical capacity was calculated. An index was obtained with Comparative Example 1 set to 100, and it was evaluated according to the following criteria. A larger initial capacity / theoretical capacity index indicates a higher initial discharge capacity of the lithium-ion secondary battery. ◎: 120 or more ○: 115 or more and less than 120 ○~△: 110 or more and less than 115 △: 105 or more and less than 110 ×: 102 or more and less than 105 ××: Less than 102

[0346] <Resistance Characteristics> For the positive electrodes prepared in the examples and comparative examples, the resistivity (Ω·cm) at the interface between the positive electrode composite layer and the current collector was measured at 25°C using an electrode resistance system (HIOKI E.E. CORPORATION "RM2610"). 2 The resistivity was measured, and an index was determined with Comparative Example 1 set to 100. The following criteria were used for evaluation. A smaller resistivity index indicates better performance. ◎: 150 or less 〇: More than 150 and less than 300 △: More than 300 and less than 500 ×: Over 500

[0347] <Cycle Characteristics> The lithium-ion secondary batteries prepared in the examples and comparative examples were left to stand at 25°C for 5 hours after electrolyte injection. Next, they were charged to a cell voltage of 3.65V using a constant current method at 25°C and 0.2C, and then subjected to an aging treatment at 60°C for 12 hours. Then, they were discharged to a cell voltage of 3.00V using a constant current method at 25°C and 0.2C. After that, CC-CV charging (upper limit cell voltage 4.35V) was performed using a constant current method at 0.2C, and CC discharge was performed to 3.00V using a constant current method at 0.2C. This charging and discharging at 0.2C was repeated three times. Next, 300 charge-discharge cycles were performed in an environment of 45°C with a cell voltage of 4.35-3.00V and a charge-discharge rate of 1.0C. The discharge capacity of the first cycle was defined as X1, and the discharge capacity of the 300th cycle as X2. Using these discharge capacities X1 and X2, the capacity retention rate = (X2 / X1) × 100 (%) was calculated, and an index was determined with Comparative Example 1 set to 100. This index was then evaluated according to the following criteria. A larger capacity retention rate index indicates superior cycle characteristics of the lithium-ion secondary battery. ◎: 95 or higher ○: 90 or higher, less than 95 ○~△: 85 or higher and less than 90 △: 80 or higher but less than 85 ×: Less than 80

[0348] <High temperature storage characteristics> The lithium-ion secondary batteries prepared in the examples and comparative examples were left to stand at 25°C for 5 hours after electrolyte injection. Next, they were charged to a cell voltage of 3.65V using a constant current method at 25°C and 0.2C, and then subjected to an aging treatment at 60°C for 12 hours. Then, they were discharged to a cell voltage of 3.00V using a constant current method at 25°C and 0.2C. After that, CC-CV charging (upper limit cell voltage 4.35V) was performed using a constant current method at 0.2C, and CC discharge was performed to 3.00V using a constant current method at 0.2C. This charging and discharging at 0.2C was repeated three times. Next, the initial IV resistance R1 was measured. Specifically, under a 25°C atmosphere, the battery was charged to 50% of the State of Charge (SOC) at 1.0C. Then, charging and discharging were performed for 20 seconds at 0.5C, 1.0C, 1.5C, and 2.0C, centered around 50% of the SOC. In each case (charging and discharging), the battery voltage after 20 seconds was plotted against the current value, and the slope was determined as the initial IV resistance R1 (Ω) (IV resistance during charging and IV resistance during discharging). Subsequently, CC-CV charging was performed at a constant current of 0.2C (maximum cell voltage 4.35V). Then, the lithium-ion secondary batteries were stored for 4 weeks in an inert oven with a nitrogen atmosphere at 80°C. After storage, the IV resistance R2 was measured using the same method as the initial IV resistance R1, after high-temperature storage. The initial IV resistance R1 and the IV resistance R2 after high-temperature storage were used to calculate the IV resistance increase rate using the following formula. IV resistance increase rate (%) = (R2 - R1) / R1 × 100 Regarding this IV resistance increase rate (%), an index was calculated with Comparative Example 1 set to 100, and it was evaluated according to the following criteria. A smaller index for the IV resistance increase rate (%) indicates that the internal resistance has been reduced over a long period, and that the battery characteristics of the lithium-ion secondary battery are superior. ◎: Less than 70 ◎~〇: 70 or more and less than 75 ○: 75 or more and less than 80 ○~△: 80 or higher and less than 85 △: 85 or higher and less than 90 △~×: 90 or higher and less than 93 ×: 93 or higher and less than 95 ××: 95 or higher

[0349] (Example 1) <Nitrile rubber manufacturing> In a reactor with an internal volume of 10 liters, 100 parts of deionized water, 35 parts of acrylonitrile, and 65 parts of 1,3-butadiene were charged. 40 parts of a 10% aqueous solution of sodium dodecylbenzenesulfonate were added as an emulsifier, and 0.1 parts of potassium phosphate were added as a stabilizer. Furthermore, molecular weight adjustment was performed. section0.27 parts of tert-dodecyl mercaptan (TDM) was added as a chain transfer agent, 0.1 parts of cumene hydroperoxide (QHPO) as a polymerization initiator, appropriate amounts of a reducing agent and a chelating agent were added, and emulsion polymerization was carried out at a temperature of 30°C to copolymerize acrylonitrile and 1,3-butadiene. When the polymerization conversion rate reached 80%, polymerization was stopped by adding 0.2 parts of hydroxylamine sulfate per 100 parts of monomer. Subsequently, the mixture was heated and steam distilled under reduced pressure at approximately 90°C to recover the residual monomer. Then, 0.1 parts of dibutylhydroxytoluene (BHT), a phenolic antioxidant, was added to obtain the polymerization solution. The polymerization solution was adjusted to pH 5.5 using buffer solutions (sulfuric acid aqueous solution, KOH aqueous solution).

[0350] In a solidification tank equipped with a thermometer and a central stirring blade device, 100 parts of the polymer solids from the obtained polymerization liquid were directly added to a 25% calcium chloride aqueous solution (4 parts as calcium chloride) heated to 45°C and vigorously stirred (600 rpm, peripheral speed 3.1 m / s). The polymer was then solidified by continuously rotating stirring blades (central part) to obtain a water-containing crumb. The obtained water-containing crumb was measured for each component using a JIS classification sieve, and the results are shown in Table 1. Note that Tables 1-1 to 1-4 below are divisions of a single table, and Tables 1-1 to 1-4 together are referred to as Table 1.

[0351] Next, the filtered water-containing crumb was added to a washing tank equipped with a stirring device and filled with deionized water at 45°C. The water-containing crumb was washed by passing 50 times the amount of deionized water (45°C) relative to the polymer while stirring. The washed water-containing crumb was heated to 60°C, then dehydrated using a steam-injected squeezer until the water content was reduced to 5%, and then dried under reduced pressure to obtain nitrile rubber A.

[0352] <Hydrogenation of nitrile rubber> (Hydrogenation reaction) Next, 9 parts of the obtained nitrile rubber A were dissolved in 141 parts of monochlorobenzene, a halogenated hydrocarbon, and added to the reactor. The reactor was then degassed three times with H2 at 0.7 MPa while stirring continued. Then, 2 L of a monochlorobenzene solution containing bis(tricyclohexylphosphine)benzylideneruthenium dichloride as a Grubbs catalyst was added so that the amount of Grubbs catalyst relative to the polymer was 2000 ppm. The temperature was then raised to 150°C, and the hydrogenation reaction was carried out under a hydrogen pressure (gauge pressure) of 8.4 MPa until the iodine value of the polymer reached 13 mg / 100 mg. During the reaction, the temperature was maintained constant using a temperature control device and a cooling coil connected to a thermal sensor.

[0353] (Catalyst removal process) After the hydrogenation reaction was complete, to remove the ruthenium catalyst, 1 part of aminopropyl-modified silica (trade name "QuadraSil AP", manufactured by SIGMA-ALDRICH, silica with aminopropyl groups introduced on its surface, average particle size 54 μm) was added to the reactor and stirred for 30 minutes. The mixture was then filtered through a 5 μm pore filter.

[0354] (Recovery of sheet-like hydrogenated nitrile rubber using a screw-type twin-screw extruder / dryer) After removing the catalyst as described above, a large amount of steam was introduced into the filtered monochlorobenzene solution containing hydrogenated nitrile rubber to isolate the water-containing crumb. Next, the isolated water-containing crumb was dehydrated and dried using a screw-type twin-screw extruder (TEX44αII: manufactured by Japan Steel Works Co., Ltd.) having a reduced-pressure drying barrel and a roughly rectangular die section, and a sheet of dried rubber (width 300 mm x thickness 30 mm) was extruded to obtain hydrogenated nitrile rubber A.

[0355] The repeating unit ratio, molecular weight, molecular weight distribution, iodine value, antioxidant content, water content, bulk density, polymer pH, and ash content of the obtained sheet-like hydrogenated nitrile rubber A were measured and are shown in Table 2. In addition, the sodium (Na), potassium (K), calcium (Ca), sulfur (S), chlorine (Cl), palladium (Pd), ruthenium (Ru), rhodium (Rh), and phosphorus (P) content in the ash were measured, and the ratio of the total amount of sodium (Na) and potassium (K) (Na+K) to the total ash, the ratio of the total amount of calcium (Ca) and sulfur (S) (Ca+S) to the total ash, and the ratio of the total amount of sodium (Na) and potassium (K) (Na+K) to the total amount of calcium (Ca) and sulfur (S) (Ca+S) were measured. mass The ratio ((Na+K) / (Ca+S)) is the ratio of calcium content (Ca) to sulfur content (S). mass The ratio (Ca / S), the relationship between calcium content (Ca) and chlorine content (Cl). mass The ratio (Ca / Cl), sulfur content (S), and chlorine content (Cl) mass The ratio (S / Cl), the percentage of ruthenium content (Ru) and rhodium content (Rh) relative to the total ash content (Ru+Rh), the percentage of palladium content (Pd) relative to the total ash content, and the percentage of phosphorus content (P) were calculated, and the results are shown in Table 2. Note that Tables 2-1 to 2-4 below are divisions of a single table, and Tables 2-1 to 2-4 together are referred to as Table 2.

[0356] The screw-type twin-screw extruder dryer used consisted of one feed barrel, three dewatering barrels (the first to third dewatering barrels), five drying barrels (the first to fifth drying barrels), and a die section. The operating conditions for the screw-type twin-screw extruder dryer were as follows.

[0357] Set temperature for each barrel: • First to third dehydration barrels: 90-120°C • First and fifth drying barrels: 120-180°C Driving conditions: • Diameter (D) of the screw inside the barrel unit: 132mm • Total length (L) of the screw inside the barrel unit: 4620 mm L / D: 35 • Rotation speed of the screw inside the barrel unit: 135 rpm ·Residence time: 100 seconds • Drying barrel pressure: 10kPa • Die resin pressure: 2MPa

[0358] (Veiled) The extruded dried rubber sheet (hydrogenated nitrile rubber sheet) was cut to a predetermined length of 650 mm after it had cooled to below 50°C, and 10 sheets were laminated to obtain hydrogenated nitrile rubber bale A. When the obtained hydrogenated nitrile rubber bale A was subjected to the same measurements as hydrogenated nitrile rubber A, the measured values ​​were the same. The properties of the hydrogenated nitrile rubber bale were the same as those of hydrogenated nitrile rubber A, and therefore were not listed in Table 1.

[0359] <Manufacturing of lithium-ion secondary batteries> (Manufacturing of binder for positive electrodes) 920 parts of NMP were measured into a 2L container equipped with stirring blades and heated to 80°C. Next, 80 parts of the hydrogenated nitrile rubber bale A prepared above, cut to approximately 1cm square, were added and dissolved while stirring for 5 hours to prepare a positive electrode binder A with a solid content of 8%. The long-term storage properties of the prepared positive electrode binder were evaluated, and the results are shown in Table 2.

[0360] (Preparation of conductive material dispersion) Conductive material dispersion A was prepared by adding 0.2 parts of TUBALL SWCNT (manufactured by OCSiAl, single-walled carbon nanotubes) as a conductive material, 25 parts (equivalent to 4 parts as solids) of a positive electrode binder composition with a solid content of 8% obtained according to the above method, and 74.8 parts of NMP as an organic solvent. The mixture was stirred using a disperser (3000 rpm, 10 minutes), and then mixed for 1 hour at a peripheral speed of 8 m / s using a bead mill (Ashizawa Finetech, "LMZ015") with 1 mm diameter zirconia beads. The dispersibility and stability of the prepared conductive material dispersion were evaluated, and the results are shown in Table 2.

[0361] (Preparation of slurry for positive electrode) In the conductive material dispersion described above, a ternary active material having a layered structure (LiNi 0.5 Co 0.2 Mn 0.3 A cathode slurry was prepared by adding 98.5 parts of O2 (average particle size: 10 μm), 1.0 part of polyvinylidene fluoride as a binder, 0.5 parts of the above conductive material dispersion (in terms of solid content), and NMP, and mixing them in a planetary mixer (60 rpm, 30 minutes). The amount of NMP added was adjusted so that the viscosity of the resulting cathode slurry (measured using a single-cylindrical rotational viscometer in accordance with JIS Z8803:1991; temperature: 25°C, rotation speed: 60 rpm) was in the range of 4000 to 5000 mPa·s. The viscosity stability of the adjusted cathode slurry was evaluated, and the results are shown in Table 2.

[0362] (Fabrication of the positive electrode) A 20 μm thick aluminum foil was prepared as the current collector. The above-mentioned positive electrode slurry was dried onto the aluminum foil using a comma coater, and the basis weight after drying was 20 mg / cm². 2 The material was applied to the surface, dried at 120°C for 5 minutes, then at 130°C for 5 minutes, and finally heat-treated at 60°C for 10 hours to obtain a cathode base. This cathode base was rolled using a roll press to obtain a density of 3.5 g / cm³. 3A sheet-like positive electrode was fabricated consisting of a positive electrode composite layer and aluminum foil. This sheet-like positive electrode was cut to a width of 4.8 cm and a length of 50 cm to form positive electrode A for lithium-ion secondary batteries. The peel strength, flexibility, and warp characteristics of the obtained positive electrode were measured, and the results are shown in Table 2.

[0363] (Fabrication of the negative electrode) In a 5 MPa pressure vessel equipped with a stirrer, 33 parts of 1,3-butadiene, 3.5 parts of itaconic acid as a carboxylic acid group-containing monomer, 63.5 parts of styrene as an aromatic vinyl monomer, 0.4 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of deionized water, and 0.5 parts of potassium persulfate as a polymerization initiator were placed and thoroughly stirred. After heating to 50°C, polymerization was started. When the polymerization conversion rate reached 96%, the mixture was cooled to stop the polymerization reaction, and a mixture containing particulate binder (styrene-butadiene copolymer) was obtained. A 5% aqueous sodium hydroxide solution was added to the above mixture to adjust the pH to 8, and unreacted monomers were removed by heated vacuum distillation. The mixture was then cooled to below 30°C to obtain an aqueous dispersion containing a binder for the negative electrode.

[0364] Next, 48.75 parts of artificial graphite and 48.75 parts of natural graphite as negative electrode active materials, and 1 part of carboxymethylcellulose as a thickener were added to a planetary mixer. Furthermore, the mixture was diluted with deionized water to a solid content of 60%, and then kneaded at a rotation speed of 45 rpm for 60 minutes. Subsequently, 1.5 parts of the aqueous dispersion containing the negative electrode binder obtained as described above was added in terms of solid content, and the mixture was kneaded at a rotation speed of 40 rpm for 40 minutes. Finally, deionized water was added to achieve a viscosity of 3000 ± 500 mPa·s (measured with a B-type viscometer at 25°C and 60 rpm) to prepare a slurry for the negative electrode composite layer.

[0365] Next, a 15 μm thick copper foil was prepared as the current collector. The above-mentioned negative electrode slurry was applied to both sides of the copper foil, with a dry coating amount of 10 mg / cm² on each side. 2 The material was applied to the surface and dried at 80°C for 5 minutes and then at 120°C for 5 minutes to obtain a negative electrode base. This negative electrode base was rolled using a roll press to obtain a density of 1.6 g / cm³. 3A sheet-like negative electrode was fabricated consisting of a negative electrode composite layer (on both sides) and copper foil. The sheet-like negative electrode was then cut to a width of 5.0 cm and a length of 52 cm to be used as a negative electrode for a lithium-ion secondary battery.

[0366] (Manufacturing of lithium-ion secondary batteries) The fabricated positive electrode and negative electrode for lithium-ion secondary batteries were placed facing each other with their electrode mixture layers facing each other, and a 15 μm thick separator (microporous polyethylene membrane) was interposed between them. The mixture was then wound around a 20 mm diameter core to obtain a wound body. The resulting wound body was then compressed from one direction at a speed of 10 mm / second until its thickness reached 4.5 mm. The compressed wound body was elliptical in plan view, and its ratio of major axis to minor axis (major axis / minor axis) was 7.7.

[0367] In addition, a 1.0 M LiPF6 solution was prepared as the electrolyte (solvent: a mixed solvent of ethylene carbonate (EC) / diethyl carbonate (DEC) = 3 / 7 (volume ratio), additive: containing 2 vol% vinylene carbonate (solvent ratio)).

[0368] Subsequently, the compressed coil was placed in an aluminum laminate case along with 3.2 g of non-aqueous electrolyte. Nickel lead wires were then connected to designated locations on the negative electrode and aluminum lead wires to designated locations on the positive electrode. Finally, the opening of the case was sealed with heat to obtain lithium-ion secondary battery A. This lithium-ion secondary battery was a pouch of a predetermined size capable of housing the above-mentioned coil, and the nominal capacity of the battery was 700 mAh.

[0369] The capacity characteristics, resistance characteristics, cycle characteristics, and high-temperature storage characteristics of the obtained lithium-ion secondary batteries were evaluated, and the results are shown in Table 2.

[0370] (Example 2) Except for changing the polymerization conversion rate to 90%, hydrogenated nitrile rubber B, hydrogenated nitrile rubber bale B, cathode binder B, conductive material dispersion B, cathode slurry B, cathode B, and lithium-ion secondary battery B were obtained in the same manner as in Example 1, and the same evaluation as in Example 1 was performed, and the results are shown in Tables 1 and 2.

[0371] (Example 3) Except for changing the water content after dehydration of the water-containing crumb to 10%, hydrogenated nitrile rubber C, hydrogenated nitrile rubber bale C, positive electrode binder C, conductive material dispersion C, positive electrode slurry C, positive electrode C, and lithium-ion secondary battery C were obtained in the same manner as in Example 1, and the same evaluation as in Example 1 was performed, and the results are shown in Tables 1 and 2.

[0372] (Example 4) Except for changing the water content of the dehydrated crumb to 25%, hydrogenated nitrile rubber D, hydrogenated nitrile rubber bale D, positive electrode binder D, conductive material dispersion D, positive electrode slurry D, positive electrode D, and lithium-ion secondary battery D were obtained in the same manner as in Example 1, and the same evaluation as in Example 1 was performed, and the results are shown in Tables 1 and 2.

[0373] (Example 5) Except for changing the water content of the dehydrated crumb to less than 1%, hydrogenated nitrile rubber E, hydrogenated nitrile rubber bale E, positive electrode binder E, conductive material dispersion E, positive electrode slurry E, positive electrode E, and lithium-ion secondary battery E were obtained in the same manner as in Example 1, and the same evaluation as in Example 1 was performed, and the results are shown in Tables 1 and 2.

[0374] (Example 6) Except for changing the method of adding the polymerization solution in the solidification reaction to a method where it is added towards the wall side from the middle of the solidification tank wall from the stirring blade of the agitated calcium chloride aqueous solution (addition position: 1 / 2 outside), hydrogenated nitrile rubber F, hydrogenated nitrile rubber bale F, positive electrode binder F, conductive material dispersion F, positive electrode slurry F, positive electrode F, and lithium-ion secondary battery F were obtained in the same manner as in Example 3, and the results were shown in Tables 1 and 2.

[0375] (Example 7) Except for changing the polymerization conversion rate to 78%, hydrogenated nitrile rubber G, hydrogenated nitrile rubber bale G, cathode binder G, conductive material dispersion G, cathode slurry G, cathode G, and lithium-ion secondary battery G were obtained in the same manner as in Example 6, and the same evaluation as in Example 6 was performed, and the results are shown in Tables 1 and 2.

[0376] (Example 8) Except for changing the polymerization conversion rate to 82%, hydrogenated nitrile rubber H, hydrogenated nitrile rubber bale H, cathode binder H, conductive material dispersion H, cathode slurry H, cathode H, and lithium-ion secondary battery H were obtained in the same manner as in Example 6, and evaluated in the same manner as in Example 6, and the results are shown in Tables 1 and 2.

[0377] (Example 9) Except for changing the polymerization conversion rate to 93%, hydrogenated nitrile rubber I, hydrogenated nitrile rubber bale I, cathode binder I, conductive material dispersion I, cathode slurry I, cathode I, and lithium-ion secondary battery I were obtained in the same manner as in Example 6, and evaluated in the same manner as in Example 6, and the results are shown in Tables 1 and 2.

[0378] (Example 10) Except for changing the amount of acrylonitrile to 22 parts and the amount of 1,3-butadiene to 78 parts in emulsion polymerization, hydrogenated nitrile rubber J, hydrogenated nitrile rubber bale J, cathode binder J, conductive material dispersion J, cathode slurry J, cathode J, and lithium-ion secondary battery J were obtained in the same manner as in Example 6, and the same evaluation as in Example 6 was performed, and the results are shown in Tables 1 and 2.

[0379] (Example 11) Except for changing the amount of acrylonitrile in emulsion polymerization to 48 parts and the amount of 1,3-butadiene to 52 parts, hydrogenated nitrile rubber K, hydrogenated nitrile rubber veil K, cathode binder K, conductive material dispersion K, cathode slurry K, cathode K, and lithium-ion secondary battery K were obtained in the same manner as in Example 6, and the same evaluation as in Example 6 was performed, and the results are shown in Tables 1 and 2.

[0380] (Example 12) Except for changing the rotation speed of the solidification tank agitator blade to 300 rpm (peripheral speed 1.6 m / s), hydrogenated nitrile rubber L, hydrogenated nitrile rubber bale L, positive electrode binder L, conductive material dispersion L, positive electrode slurry L, positive electrode L, and lithium-ion secondary battery L were obtained in the same manner as in Example 6, and the same evaluation as in Example 6 was performed, and the results are shown in Tables 1 and 2.

[0381] (Reference example 1) Except for changing the rotation speed of the solidification tank agitator blade to 100 rpm (peripheral speed 0.5 m / s) and changing the water content after dewatering to 25%, hydrogenated nitrile rubber M, hydrogenated nitrile rubber bale M, positive electrode binder M, conductive material dispersion M, positive electrode slurry M, positive electrode M, and lithium-ion secondary battery M were obtained in the same manner as in Example 6, and the same evaluation as in Example 6 was performed, and the results are shown in Tables 1 and 2.

[0382] (Reference example 2) Except for changing the coagulation reaction to a method of adding an aqueous calcium chloride solution to the polymerization liquid being stirred in the coagulation tank and changing the water content after dehydration to 25%, hydrogenated nitrile rubber N, hydrogenated nitrile rubber bale N, positive electrode binder N, conductive material dispersion N, positive electrode slurry N, positive electrode N, and lithium-ion secondary battery N were obtained in the same manner as in Example 6, and the results were shown in Tables 1 and 2.

[0383] (Reference example 3) Except for introducing a large amount of steam into the filtrate after the catalyst removal process to produce a water-containing crumb, which was then dried under reduced pressure at 90°C without being subjected to a screw-type twin-screw extruder to produce a crumb-shaped hydrogenated nitrile rubber O, and not producing a hydrogenated nitrile rubber bale, the process was the same as in Reference Example 2 to obtain a positive electrode binder O, a conductive material dispersion O, a positive electrode slurry O, a positive electrode O, and a lithium-ion secondary battery O. The same evaluation as in Reference Example 2 was performed, and the results are shown in Tables 1 and 2.

[0384] (Reference example 4) 20 kg of the clam-shaped hydrogenated nitrile rubber P obtained in Reference Example 3 was filled into a 300 × 650 × 300 mm bailer and compacted at a pressure of 3 MPa for 30 seconds to obtain a hydrogenated nitrile rubber bale P. Then, the hydrogenated nitrile rubber bale P was dissolved in NMP to produce a positive electrode binder P. Using these, a conductive material dispersion P, a positive electrode slurry P, a positive electrode P, and a lithium-ion secondary battery P were obtained in the same manner as in Reference Example 3, and the same evaluation as in Reference Example 3 was performed, and the results are shown in Tables 1 and 2.

[0385] (Reference example 5) Except for adjusting the pH of the emulsion polymerization solution after emulsion polymerization to 3.5, a hydrogenated nitrile rubber veil Q, a positive electrode binder Q, a conductive material dispersion Q, a positive electrode slurry Q, a positive electrode Q, and a lithium-ion secondary battery Q were obtained in the same manner as in Reference Example 4, and the same evaluation as in Reference Example 4 was performed, with the results shown in Tables 1 and 2.

[0386] (Reference example 6) Except for changing the pH of the emulsion polymerization solution after emulsion polymerization to 9, a hydrogenated nitrile rubber veil R, a positive electrode binder R, a conductive material dispersion R, a positive electrode slurry R, ​​a positive electrode R, and a lithium-ion secondary battery R were obtained in the same manner as in Reference Example 4, and the same evaluation as in Reference Example 4 was performed, and the results are shown in Tables 1 and 2.

[0387] (Comparative Example 1) Except for changing the rotation speed of the solidification tank agitator blade to 100 rpm (peripheral speed 0.5 m / s) and not performing dewatering, a hydrogenated nitrile rubber bale S, a positive electrode binder S, a conductive material dispersion S, a positive electrode slurry S, a positive electrode S, and a lithium-ion secondary battery S were obtained in the same manner as in Reference Example 3, and the same evaluation as in Reference Example 2 was performed, and the results are shown in Tables 1 and 2.

[0388] (Comparative Example 2) Except for changing the polymerization conversion rate to 70%, hydrogenated nitrile rubber T, cathode binder T, conductive material dispersion T, cathode slurry T, cathode T, and lithium-ion secondary battery T were obtained in the same manner as in Comparative Example 1, and evaluated in the same manner as in Comparative Example 1. The results are shown in Tables 1 and 2.

[0389] (Comparative Example 3) Except for not adding an antioxidant to the emulsion polymerization solution after emulsion polymerization, hydrogenated nitrile rubber U, cathode binder U, conductive material dispersion U, cathode slurry U, cathode U, and lithium-ion secondary battery U were obtained in the same manner as in Comparative Example 1, and evaluated in the same manner as in Comparative Example 1. The results are shown in Tables 1 and 2.

[0390] [Table 1-1]

[0391] [Table 1-2]

[0392] [Table 1-3]

[0393] [Table 1-4]

[0394] [Table 2-1]

[0395] [Table 2-2]

[0396] [Table 2-3]

[0397] [Table 2-4] Table 2 shows that the polymer contains acrylonitrile polymerization units and 1,3-butadiene polymerization units, with the proportion of acrylonitrile polymerization units being 28% by mass or more and 40% by mass or less, the total proportion of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization units being 7% by mass or more, the weight-average molecular weight (Mw) being in the range of 10,000 to 2,500,000, the polymer containing an antioxidant, the polymer pH being 4.5 to 6, the iodine value being 100 mg / 100 mg or less, and the bulk density being 0.7 g / cm³. 3 As described above, the hydrogenated nitrile rubbers A to L of the present invention exhibit excellent dispersibility and stability of conductive material dispersions, excellent viscosity stability of cathode slurries, excellent peel strength and warping characteristics of electrodes, and excellent capacitance, resistance, and cycle characteristics of electrochemical elements.

[0398] Regarding the dispersibility of the conductive material dispersion, the hydrogenated nitrile rubbers A to L of the present invention exhibit good dispersibility. On the other hand, when the proportion of acrylonitrile polymerization units in the hydrogenated nitrile rubber decreases, there is a tendency for the dispersibility of the conductive material dispersion to decrease (Example 10). Although not shown in this example, when the Mw or Mz / Mw of the hydrogenated nitrile rubber becomes excessively large, there is a tendency for the dispersibility of the conductive material dispersion to decrease.

[0399] Regarding the stability of the conductive material dispersion, hydrogenated nitrile rubbers A to L of the present invention all exhibit good stability, but stability deteriorates when the bulk density decreases and the amount of internal air increases, indicating a correlation between the two properties (comparison between Examples 1 to Reference Example 2 and Reference Example 3 to Comparative Example 3). Furthermore, if hydrogenated nitrile rubber that does not contain antioxidants such as phenolic antioxidants is used, the stability of the conductive material dispersion decreases even further (Comparative Example 3).

[0400] Regarding the viscosity stability of the cathode slurry, hydrogenated nitrile rubbers A to L of the present invention all exhibit good stability, but this stability decreases as the polymer pH increases (Reference Example 6).

[0401] Regarding the peel strength of the electrodes, hydrogenated nitrile rubbers A to L of the present invention all show good results. Furthermore, the peel strength of the electrodes tends to decrease when the ash content of the specific ash component described later is excessively reduced, indicating that the ash content of the specific component of the hydrogenated nitrile rubber improves the peel strength of the electrodes (Example 5). On the other hand, the peel strength of the electrodes deteriorates when the hydrogenated nitrile rubber does not contain an anti-aging agent (Comparative Example 3). In addition, although comparative examples are not shown in this example, the peel strength of the electrodes decreases when the Mw or Mz / Mw of the hydrogenated nitrile rubber is excessively small.

[0402] Regarding the flexibility of the electrodes, all of the hydrogenated nitrile rubbers A to L of the present invention exhibit good flexibility, however, flexibility tends to decrease as the proportion of 1,2-bonding units in the 1,3-butadiene polymerization units of the hydrogenated nitrile rubber increases (Example 9).

[0403] The electrode's warp characteristics can be improved by increasing the proportion of 1,2-bonding units in the 1,3-butadiene polymerization units of the hydrogenated nitrile rubber (Examples 6-9), while they worsen if the proportion is excessively small (Comparative Example 2). This indicates that adjusting the proportion of 1,2-bonding units in the 1,3-butadiene polymerization units of the hydrogenated nitrile rubber is necessary to achieve a high level of both electrode warp characteristics and flexibility, and to achieve a high level of balance.

[0404] Regarding capacity characteristics, it can be seen that the ash content and ash components of the hydrogenated nitrile rubber have a significant impact. In particular, it can be seen that the characteristics can be almost completely improved by reducing the ash content of the hydrogenated nitrile rubber to 0.5% by mass. This is because when the ash content is reduced to about 0.5% by mass, the sodium and potassium content in the ash almost disappears, and it is presumed that the deterioration of capacity characteristics is caused by the sodium and potassium in the ash destroying the negative electrode active material. Furthermore, it can be seen that capacity characteristics can be improved by increasing the proportion of 1,2-bonding units in the 1,3-butadiene polymerization units (Examples 1-2, Examples 6-9 and Comparative Example 2).

[0405] Regarding resistance characteristics, the hydrogenated nitrile rubbers A to L of the present invention show good results. On the other hand, when the proportion of acrylonitrile polymerization units in the hydrogenated nitrile rubber is reduced, or when the polymer pH is lowered, the dispersibility of the conductive material dispersion and the resistance characteristics of the electrochemical element decrease (Example 10 and Reference Example 5). Although comparative examples are not shown in this example, when the Mw or Mz / Mw of the hydrogenated nitrile rubber becomes excessively large, the dispersibility of the conductive material dispersion and the resistance characteristics of the electrochemical element tend to decrease.

[0406] Regarding cycle characteristics, all of the hydrogenated nitrile rubbers A to L of the present invention show good results, but it can be seen that they tend to decrease as the number of acrylonitrile polymerization units increases (Example 11). In addition, although not shown in this example, cycle characteristics deteriorate when the iodine value of the hydrogenated nitrile rubber significantly exceeds 100 mg / 100 mg.

[0407] Furthermore, regarding the long-term storage properties of the positive electrode binder, the hydrogenated nitrile rubbers A to L of the present invention are found to be good (Examples 1 to 12 and Reference Examples 1 to 2). On the other hand, the properties deteriorate when the D50 / D10 or D90 / D10 in the particle size distribution of the hydrogenated nitrile rubber increases (Reference Examples 3 to Comparative Example 2).

[0408] Regarding high-temperature storage characteristics, it can be seen that the ash content of hydrogenated nitrile rubber has a significant impact. However, unlike the relationship between the volume characteristics and the sodium and potassium content in the ash, it can be seen that even when the ash content is 0.5% by mass or less, the lower the ash content, the better the high-temperature storage characteristics become. When the ash content is 0.5% by mass or less, the ash components consist of calcium and sulfur, and their impact on high-temperature storage characteristics is smaller than that of sodium and potassium. Furthermore, as the ash content, which is high in calcium and sulfur, is reduced, the peel strength of the electrode tends to decrease (Example 5), indicating that this ash content works well for electrode peel strength.

[0409] As shown in Table 2 above, the hydrogenated nitrile rubbers A to L of the present invention enhance the long-term storage properties of the positive electrode binder, the dispersibility and stability of the conductive material dispersion, the viscosity stability of the positive electrode slurry, the peel strength, flexibility and warping characteristics of the electrode, and the capacitance, resistance, cycle characteristics and high-temperature storage characteristics of the electrochemical element, demonstrating a high degree of balance among these properties. [Explanation of Symbols]

[0410] 10 Emulsion polymerization equipment 11 Polymerization can 12, 32, 52, 122, 132, 152a, 152b Stirring device 13, 33, 53, 123, 133, 153a, 153b stirring blade 14, 34, 54, 124, 134, 154a, 154b motors 30, 150 coagulation equipment 31 Solidification Tank 38, 58, 158 Drainer 50 Cleaning device 51 Washing Tank 55, 71c, 125, 135, 155a heating device 56 Heating section 70 Squeezer 70a Clam supply section 70b Clam discharge section 71 Heating mechanism 71a, 72a Chamber 71b, 72b Laura 72 Pressurization mechanism 73 Connecting part 75, 110 Crushing device 111 Conveyor 120 Melting equipment 121 Dissolution Tank 126, 136 Heating equipment 130 Hydrogenation Reactor 131 Reaction tank 137 Hydrogen supply sources 138 Catalyst Source 151a First solidification tank 151b Second solidification tank 156a Heating section 157a, 157b pumps 160 Screw-type twin-screw extruder dryer 161 Supply barrel section 162 Dehydration barrel section 163 Drying barrel section 164 Die section 165 Screw drive unit 170 Cooling device 171 Shower device 172, 185 Roller conveyor 173 Conveyor-type cooling device 174 Conveyor 175 Cooling means 176 Air cooling tank 177 Air supply duct 180 Cutting device 181 Clamper 182 Cutter 183 Workbench 190 Packaging equipment

Claims

1. The polymer contains acrylonitrile polymerization units and 1,3-butadiene polymerization units, wherein the proportion of acrylonitrile polymerization units is 28% by mass or more and 40% by mass or less, the total proportion of 1,2-bonding units and their hydride units in the 1,3-butadiene polymerization units is 7% by mass or more, the weight-average molecular weight (Mw) measured with tetrahydrofuran (THF) as a solvent is in the range of 10,000 to 2,500,000, it contains an antioxidant, and the polymer pH measured at 25°C in an extract obtained by adding 90g of deionized water to 10g of NMP solution (solid content concentration: 8% by mass) is 4.5 to 6, the iodine value is 100mg / 100mg or less, and the bulk density is 0.7g / cm³. ３ That is hydrogenated nitrile rubber.

2. The hydrogenated nitrile rubber according to Claim 1, wherein the total ratio of the acrylonitrile polymerization units to the 1,3-butadiene polymerization units is 70 to 100% by mass.

3. The aforementioned bulk density is 0.8 cm ３ The hydrogenated nitrile rubber according to claim 1, wherein the amount is 1 / g or more.

4. The hydrogenated nitrile rubber according to claim 1, wherein the content of the anti-aging agent is in the range of 0.001 to 2% by mass.

5. The hydrogenated nitrile rubber according to claim 1, wherein the polymer pH is 4.5 or more and 5.5 or less.

6. The hydrogenated nitrile rubber according to claim 1, wherein the iodine value is 50 mg / 100 mg or less.

7. The hydrogenated nitrile rubber according to claim 1, wherein the weight-average molecular weight (Mw) is 30,000 or more and 1,000,000 or less.

8. The hydrogenated nitrile rubber according to claim 1, wherein the ash content is 0.7% by mass or less.

9. The hydrogenated nitrile rubber according to claim 1, wherein the ash content is 0.01% by mass or more.

10. The hydrogenated nitrile rubber according to claim 8, wherein the ratio of the total amount (Ca + S) of calcium content (Ca) and sulfur content (S) in the ash is 30% by mass or more.

11. The hydrogenated nitrile rubber according to claim 8, wherein the ratio of the total amount (Na + K) of sodium content (Na) and potassium content (K) in the ash is 20% by mass or less.

12. The hydrogenated nitrile rubber according to claim 8, wherein the mass ratio (Ca / Cl) of calcium content (Ca) to chlorine content (Cl) in the ash is 1 or more.

13. The hydrogenated nitrile rubber according to claim 8, wherein the mass ratio (S / Cl) of sulfur content (S) to chlorine content (Cl) in the ash is 1 or more.

14. The hydrogenated nitrile rubber according to claim 8, wherein the mass ratio (Ca / S) of the calcium content (Ca) to the sulfur content (S) in the ash is 3.5 or less.

15. The hydrogenated nitrile rubber according to claim 8, wherein the mass ratio ((Na+K) / (Ca+S)) of the total amount of sodium content (Na) and potassium content (K) in the ash (Na+K) to the total amount of calcium content (Ca) and sulfur content (S) (Ca+S) is 0.5 or less.

16. The hydrogenated nitrile rubber according to claim 8, wherein the content (M) of the metal used in the hydrogenation catalyst in the ash is 1% by mass or less.

17. The hydrogenated nitrile rubber according to claim 8, wherein the ratio of the total amount (Rh + Ru) of rhodium content (Rh) and ruthenium content (Ru) in the ash is 1% by mass or less.

18. The hydrogenated nitrile rubber according to claim 8, wherein the phosphorus content (P) ratio in the ash is 10% by mass or less.

19. The hydrogenated nitrile rubber according to claim 1, wherein the ratio of the Z-average molecular weight (Mz) to the weight-average molecular weight (Mw) (Mz / Mw), measured using tetrahydrofuran (THF) as a solvent, is 1.5 or more.

20. The hydrogenated nitrile rubber according to claim 1, wherein the weight-average molecular weight (NMP-Mw) measured with N-methylpyrrolidone (NMP) and the weight-average molecular weight (THF-Mw) measured with tetrahydrofuran (THF) are in the relationship NMP-Mw ≥ THF-Mw.

21. The hydrogenated nitrile rubber according to claim 1, wherein the water content is less than 1% by mass.

22. The hydrogenated nitrile rubber according to claim 1, wherein the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn) is 2.5 or more.

23. The hydrogenated nitrile rubber according to claim 1, wherein the ratio (D90 / D10) of the particle size D90 when 90% of the total volume is present to the particle size D10 when 10% of the total volume is present is 150 or less.

24. The hydrogenated nitrile rubber according to claim 1, which is obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene and coagulation with calcium chloride, and then hydrogenating the polymer.

25. The hydrogenated nitrile rubber according to claim 1, wherein the polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene using an alkali metal salt as a polymerization auxiliary material is hydrogenated.

26. The hydrogenated nitrile rubber according to claim 1, wherein a polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene using sulfate and / or sulfonate as polymerization auxiliary materials is hydrogenated.

27. The hydrogenated nitrile rubber according to claim 1, wherein at least one salt compound selected from the group consisting of alkali metal salts, sulfates, and sulfonates is used as a polymerization auxiliary material, and a polymer obtained by emulsion polymerization of acrylonitrile and 1,3-butadiene and coagulation with calcium chloride is hydrogenated.

28. An emulsion polymerization step to obtain an emulsion polymerization solution by emulsion polymerization of monomer components containing acrylonitrile and 1,3-butadiene, The process involves adding an antioxidant to the resulting emulsion polymerization solution, A coagulation step in which an emulsion polymerization solution to which an antioxidant is added is brought into contact with a coagulation solution to produce a hydrated crumb, The resulting water-containing crumb is washed, dehydrated, and dried in a washing, dehydration, and drying process. A hydrogenation step involves dissolving a dried polymer in an organic solvent and carrying out a hydrogenation reaction, A hydrogenated polymer dehydration and drying process is performed in which the reaction solution after the hydrogenation reaction is solidified to produce a water-containing crumb, which is then dehydrated and dried using a screw-type twin-screw extruder to extrude the dried rubber. A method for producing hydrogenated nitrile rubber according to any one of claims 1 to 27, comprising:

29. A hydrogenated nitrile rubber bale obtained by bailing the hydrogenated nitrile rubber according to any one of claims 1 to 27.

30. A positive electrode material comprising hydrogenated nitrile rubber according to any one of claims 1 to 27.

31. A cathode binder obtained by dissolving the hydrogenated nitrile rubber described in any one of claims 1 to 27 in N-methylpyrrolidone (NMP).

32. A conductive material dispersion liquid obtained by dissolving or dispersing the hydrogenated nitrile rubber and conductive material described in any one of claims 1 to 27 in N-methylpyrrolidone (NMP).

33. A slurry for a positive electrode, comprising a positive electrode active material, a conductive material, and a hydrogenated nitrile rubber according to any one of claims 1 to 27, dissolved or dispersed in N-methylpyrrolidone (NMP).

34. A positive electrode comprising the hydrogenated nitrile rubber described in any one of claims 1 to 27.

35. An electrochemical element comprising the hydrogenated nitrile rubber described in any one of claims 1 to 27.

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