WO2021106450A1 - Cellulose derivative and cellulose derivative solution - Google Patents

Cellulose derivative and cellulose derivative solution Download PDF

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Publication number
WO2021106450A1
WO2021106450A1 PCT/JP2020/039751 JP2020039751W WO2021106450A1 WO 2021106450 A1 WO2021106450 A1 WO 2021106450A1 JP 2020039751 W JP2020039751 W JP 2020039751W WO 2021106450 A1 WO2021106450 A1 WO 2021106450A1
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Prior art keywords
cellulose derivative
degree
cellulose
solvent
methyl
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PCT/JP2020/039751
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French (fr)
Japanese (ja)
Inventor
由紀子 松尾
知弘 橋爪
大村　雅也
梶原　理恵
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株式会社ダイセル
御国色素株式会社
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Publication of WO2021106450A1 publication Critical patent/WO2021106450A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B11/00—Preparation of cellulose ethers
    • C08B11/02—Alkyl or cycloalkyl ethers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B11/00—Preparation of cellulose ethers
    • C08B11/02—Alkyl or cycloalkyl ethers
    • C08B11/04—Alkyl or cycloalkyl ethers with substituted hydrocarbon radicals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/08—Cellulose derivatives
    • C08L1/26—Cellulose ethers
    • C08L1/28—Alkyl ethers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a cellulose derivative and a cellulose derivative solution.
  • a lithium ion secondary battery usually includes a negative electrode made of a carbon material, a positive electrode containing an active material that reversibly moves lithium ions in and out, and a non-aqueous electrolyte in which they are immersed.
  • the positive electrode is manufactured by applying an electrode paste made of a positive electrode active material, a conductive material, and a binder to a current collector plate.
  • a positive electrode active material a lithium transition metal composite oxide or the like is used. Since such a positive electrode active material alone has poor electron conductivity, that is, conductivity, conductive carbon black having a highly developed structure in order to impart conductivity, graphite having a crystal showing remarkable anisotropy, etc.
  • Carbon material is added as a conductive material and dispersed in a non-aqueous solvent such as N-methyl-2-pyrrolidone (NMP) together with a binder (binding material) to prepare a slurry, and this slurry is applied onto a metal foil. And dry to form a positive electrode.
  • NMP N-methyl-2-pyrrolidone
  • carbon black and graphite which are carbon materials used as conductive materials
  • carbon black and graphite are fine powders having a small primary particle size, and have a large structure and specific surface area, so that they have strong cohesive force. It is difficult to uniformly mix and disperse in it. If the dispersibility and particle size of the carbon material, which is the conductive material, are not sufficiently controlled, the internal resistance of the electrode cannot be reduced because a uniform conductive network is not formed, and as a result, lithium, which is the positive electrode active material, cannot be reduced. There is a problem that the performance of transition metal composite oxides and graphite, which is a carbon material, cannot be sufficiently brought out.
  • the conductive material (conductive auxiliary agent) in the electrode mixture is insufficiently dispersed, a resistance distribution is generated on the electrode plate due to partial aggregation, and the current is concentrated when used as a battery. Problems such as partial heat generation and accelerated deterioration may occur.
  • a dispersion liquid (conductive material dispersion liquid) that is dispersed in a dispersion medium such as an organic solvent together with a dispersant and made into a sol is prepared in advance, and this is kneaded together with an active material and a binder. It has been proposed to form an electrode (Patent Document 1).
  • a dispersant for a battery has been proposed in which dispersion stabilization is achieved without impairing the conductivity of the conductive auxiliary agent and the wettability of the conductive auxiliary agent with respect to an electrolytic solution is improved (Patent Document 2).
  • Patent Document 3 a conductive material dispersion liquid capable of ensuring good dispersibility and conductivity has been proposed.
  • a material used for a dispersant or a binder a cellulosic resin having excellent solubility in a polar non-aqueous solvent such as N-methyl-2-pyrrolidone (NMP) is known (Patent Document 3).
  • NMP N-methyl-2-pyrrolidone
  • the conductive material dispersion liquid has too high thixotropy property, so that the storage stability becomes insufficient and the viscosity such as thickening with time changes. Cheap.
  • a conductive material dispersion liquid is kneaded together with an active material and a binder to form an electrode, the workability is inferior.
  • An object of the present disclosure is to provide a cellulose derivative capable of obtaining a conductive material dispersion liquid of a lithium ion secondary battery having excellent storage stability.
  • the first of the present disclosure relates to a cellulose derivative having a methyl group substitution degree of 1.0 or more and an octyl group substitution degree of 0.01 or more and less than 0.6.
  • the sum of the degree of methyl group substitution and the degree of octyl substitution may be 1.5 or more.
  • the degree of octyl group substitution may be 0.06 or more and less than 0.3.
  • the second aspect of the present disclosure is that the cellulose derivative and the solvent are contained, and the content of the cellulose derivative is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent.
  • the present invention relates to a cellulose derivative solution containing one or more selected from the group consisting of N-methyl-2-pyrrolidone and dimethylacetamide.
  • the cellulose derivative of the present disclosure it is possible to obtain a conductive material dispersion liquid of a lithium ion secondary battery having excellent storage stability.
  • the cellulose derivative of the present disclosure has a methyl group substitution degree of 1.0 or more and an octyl group substitution degree of 0.01 or more and less than 0.6.
  • the cellulose derivative of the present disclosure is cellulose in which some or all of the hydrogen of the hydroxyl group is substituted with a methyl group and an octyl group.
  • the degree of methyl group substitution of the cellulose derivative is 1.0 or more, may be 1.5 or more, and may be 1.8 or more. Further, the degree of methyl group substitution of the cellulose derivative may be less than 2.99, may be 2.94 or less, may be 2.9 or less, may be 2.5 or less, and may be 2.4. It may be less than or equal to, and may be less than or equal to 2.0. If the degree of methyl group substitution of the cellulose derivative is too small, the solubility in a polar non-aqueous solvent such as NMP is poor, and the conductive material cannot be dispersed. If the degree of methyl group substitution is too large, it becomes difficult to introduce an octyl group during the production of a cellulose derivative.
  • the degree of octyl group substitution of the cellulose derivative is 0.01 or more, may be 0.06 or more, may be 0.08 or more, may be 0.1 or more, and may be 0.2 or more. It's okay. Further, the degree of octyl group substitution may be less than 0.5, less than 0.4, and less than 0.3, where it is less than 0.6. If the degree of octyl group substitution of the cellulose derivative is too small, the conductive material dispersion liquid containing the cellulose derivative has high thixotropy property, tends to thicken with time, and has insufficient storage stability.
  • the conductive material dispersion containing the cellulose derivative will not only have insufficient storage stability, but will also be inferior in solubility in a polar solvent, resulting in a solvent for a non-aqueous electrolyte (a solvent for a non-aqueous electrolyte). Poor solubility in non-polar solvents).
  • the octyl group substitution degree is preferably 0.06 or more and less than 0.3.
  • the sum of the degree of methyl group substitution and the degree of octyl group substitution of the cellulose derivative is preferably 1.5 or more, preferably 1.7 or more, and may be 2.0 or more. The sum may be less than 3.0, less than 2.9, and less than 2.6.
  • the sum of the degrees of substitution of each substituent of the cellulose derivative is called the total degree of substitution, and the total degree of substitution of the cellulose derivative may be 1.5 or more, 1.7 or more, and 2.0 or more. It's okay. Further, where the maximum value of the total substitution degree is 3.0, the total substitution degree may be less than 3.0, less than 2.9, and less than 2.6.
  • the degree of alkyl group substitution including the degree of methyl group substitution and the degree of octyl group substitution can be measured by the following method. It can be measured by a method according to ASTM: D-817-91, 13 C-NMR, and 1 H-NMR.
  • the weight average molecular weight is a so-called weighted average value of molecular weight, which is obtained by multiplying the weight of each molecule by the molecular weight to obtain an average value, and can be measured by GPC.
  • the cellulose derivative of the present disclosure it is possible to obtain a conductive material dispersion liquid of a lithium ion secondary battery having excellent storage stability without excessively high thixotropy.
  • the cellulose derivative can be produced, for example, as follows. Examples thereof include a production method including a step of converting a cellulose raw material into alkaline cellulose under basic conditions (activation step); and a step of reacting the alkali cellulose with an alkyl halide (etherification treatment).
  • a step of marcelifying a cellulose raw material with sodium hydroxide to obtain alkali cellulose a step of reacting the alkali cellulose with a methylating agent to etherify it to obtain methyl cellulose; and then a base.
  • Examples thereof include a production method (referred to as a two-step reaction) having a step of obtaining methyl octyl cellulose (cellulose derivative) by reacting the methyl cellulose with an octylizing agent to etherify it under sexual conditions.
  • methyloctyl cellulose (cellulose derivative) can also be obtained by reacting the alkaline cellulose with both a methylating agent and an octylizing agent to etherify it (referred to as a one-step reaction).
  • the blending amount and blending ratio of the methylating agent and the octylling agent can be arbitrarily selected.
  • methyl cellulose is reacted with an octylizing agent to etherify the methyl octyl cellulose (cellulose).
  • a production method (two-step reaction) having a step of obtaining a derivative) is preferable.
  • methylating agent examples include methyl halides such as methyl chloride
  • octylizing agent examples include octyl halides such as octyl chloride.
  • the cellulose derivative solution of the present disclosure contains the cellulose derivative and the solvent, and the content of the cellulose derivative is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent.
  • the cellulose derivative solution is a solution in which the cellulose derivative is dissolved in a solvent, and it is visually observed whether or not the solution is a solution.
  • a solution in which the cellulose derivative is dissolved in a solvent, and it is visually observed whether or not the solution is a solution.
  • the shape of a solid substance, a swollen body, a gel-like body, or the like of a cellulose derivative is observed, it cannot be said to be a solution. If these shapes cannot be confirmed and are transparent, it is a solution.
  • Examples of the solvent for the cellulose derivative solution include N-methylpyrrolidone, N-ethylpyrrolidone, N, N-dimethylformamide, tetrahydrofuran, dimethylacetamide, dimethylsulfoxide, hexamethylsulfolamide, tetramethylurea, acetone, and methylethylketone.
  • a mixed solvent of N-methylpyrrolidone and an ester solvent for example, ethyl acetate, n-butyl acetate, butyl cellosolve acetate, and butyl carbitol acetate, etc.
  • an N-methylpyrrolidone and a glyme-based solvent for example, diglime, triglime, and the like.
  • Examples thereof include a mixed solvent of a mixed solution of (tetraglyme, etc.).
  • a solvent containing one or more selected from the group consisting of N-methyl-2-pyrrolidone and dimethylacetamide is preferable. It is relatively volatile and easy to mix with many organic solvents and easy to handle. Therefore, a slurry of electrode materials can be stably produced.
  • the content of the cellulose derivative in the cellulose derivative solution is 0.1 parts by mass or more and 20 parts by mass or less, preferably 0.1 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the solvent. More preferably, it is 5 parts by mass or more.
  • the thixotropy index value of the cellulose derivative solution of the present disclosure is preferably less than 10, more preferably less than 5. Moreover, it may be 1 or more.
  • the thixotropy index value is an index of thixotropy in which the viscosity decreases as the applied force increases. The larger the value, the higher the thixotropy.
  • the thixotropy index value can be measured by the following method. First, 5 parts by mass of a sample is dissolved in 95 parts by mass of NMP to prepare an NMP solution, and the viscosity at a rotation speed of 0.5 rpm under the following devices and conditions (1) to (4). , And the viscosity at a rotation speed of 50 rpm.
  • Measuring jig Cone plate (1 ° 34'x R24), (3) Temperature: 25 ° C (4) Rotation speed: 0.5 rpm, 50 rpm
  • the viscosity at a rotation speed of 0.5 rpm / the viscosity at a rotation speed of 50 rpm is calculated as a thixotropy index value (TI value).
  • the cellulose derivative of the present disclosure has both excellent solubility in a polar non-aqueous solvent and excellent solubility resistance in a non-aqueous electrolyte solvent (non-polar solvent), so that a conductive material is dispersed for the positive electrode of a lithium ion secondary battery. It is suitably used as a material for forming a positive electrode of a lithium ion secondary battery such as a liquid.
  • the excellent solubility resistance of non-aqueous electrolytes to solvents (non-polar solvents) suppresses the decrease in capacity due to charging and discharging when using lithium-ion secondary batteries, and improves cycle characteristics. Contributes to performance improvement.
  • a conductive material dispersion liquid for a positive electrode of a lithium ion secondary battery by mixing the cellulose derivative dissolution liquid of the present disclosure together with, for example, a conductive material, a dispersant, a dispersion medium and the like.
  • the conductive material dispersion liquid for the positive electrode of the lithium ion secondary battery contains, for example, the cellulose derivative dissolution liquid of the present disclosure.
  • the conductive material conventionally known substances can be used, and examples thereof include carbon black and carbon nanotubes.
  • dispersant examples include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polyhexafluoropropylene, polyethylene, polypropylene, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid, and polyvinyl.
  • PVDF polyvinylidene fluoride
  • PVDF polytetrafluoroethylene
  • polyhexafluoropropylene polyethylene
  • polypropylene polymethyl methacrylate
  • polyvinyl chloride polyvinylidene chloride
  • polyvinyl acetate polyacrylic acid
  • polyvinyl polyvinylidene fluoride
  • Nonionic dispersants for organic materials such as based resins (excluding methyloctyl cellulose), polyalkylene oxides, polyvinyl ethers, polyvinylpyrrolidones, chitins, chitosans, and starch, as well as glass, alumina, silica, ceramics, and locks. Examples thereof include nonionic dispersants for inorganic materials such as wool.
  • dispersion medium examples include aliphatic hydrocarbon-based dispersion media such as pentane, normal hexane, octane, cyclopentane, and cyclohexane; aromatic hydrocarbon-based dispersion media such as benzene, toluene, xylene, and simene; and furfural and the like.
  • Alcohol-based dispersion medium such as acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone; butyl acetate, ethyl acetate, methyl acetate, butyl propionate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, 3 -Ester-based dispersion media such as methoxybutyl acetate and ethylene glycol diacetate; ether-based dispersion media such as tetrahydrofuran, dioxane, and ethylene glycol dimethyl ether; methanol, ethanol, normal propyl alcohol, isopropyl alcohol, butyl alcohol, octyl alcohol, cyclo Alcohol-based dispersion media such as hexanol, allyl alcohol, benzyl alcohol, cresol, and furfuryl alcohol; polyol-based dispersion media such as hexanol,
  • NMP N-methyl-2-pyrrolidone
  • DMAc dimethylacetamide
  • ⁇ Easy complete dissolution at room temperature
  • a thixotropy index value (TI value)
  • TI value thixotropy index value
  • reaction Stirring at temperature (2)) for 3 hours (reaction time (2)) (second step).
  • reaction time (2) reaction time (2)
  • second step After returning to room temperature, the residual gas in the system was exhausted and poured into 12 L of methanol with vigorous stirring to obtain a white solid (third step).
  • the white solid was filtered off by suction filtration and washed 3 times with a large amount of isopropyl alcohol.
  • the obtained white solid was vacuum dried at 100 ° C. for 6 hours to obtain methyl cellulose (MC-1) as a white powder (yield 98 g).
  • the degree of methyl group substitution of methyl cellulose (MC-1) is shown in Table 1.
  • MC-2-5) Each methyl cellulose (MC-2, MC-3, MC-4 and MC-5) was prepared in the same manner as in the synthesis of MC-1 except that the conditions in the first step and the second step were changed as shown in Table 1. Obtained. The degree of methyl group substitution of each methyl cellulose is shown in Table 1.
  • MC-6 Methyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as MC-6.
  • Example 1 ⁇ Synthesis of methyloctyl cellulose> (Example 1) To a 2 L autoclave with a stirrer, 100 g of methyl cellulose (MC-5) and 130 g of a 48% sodium hydroxide aqueous solution were added as raw materials. After stirring at room temperature for 1 hour, 500 mL of toluene and 480 g of octyl chloride were added, and the mixture was stirred at room temperature for 30 minutes. Further, the mixture was stirred at 130 ° C. (reaction temperature) for 10 hours (reaction time), and after the reaction was completed, the temperature was returned to room temperature.
  • reaction temperature reaction temperature
  • the white solid was filtered by suction filtration and then washed 3 times with a large amount of isopropyl alcohol.
  • the obtained white solid was vacuum dried at 100 ° C. for 6 hours to obtain methyloctyl cellulose as a white powder (yield 101 g).
  • Table 3 shows the results of evaluating each physical property of the obtained methyloctyl cellulose.
  • Example 2 Each methyloctyl cellulose was obtained in the same manner as in Example 1 except that the raw material, the amount of octyl chloride, the amount of 48% aqueous sodium hydroxide solution, and the reaction temperature and reaction time were changed as shown in Table 2.
  • Table 3 shows the results of evaluating each physical property of the obtained methyloctyl cellulose.
  • the cellulose derivative of the example As shown in Table 3, according to the cellulose derivative of the example, it can be seen that the thixotropy index value does not become too high and a cellulose derivative solution having excellent storage stability can be obtained. Further, it was shown that the cellulose derivative of the example has excellent solubility in a polar non-aqueous solvent and excellent solubility resistance in a solvent (non-polar solvent) of a non-aqueous electrolyte. It can be seen that it is suitable as a material constituting the conductive material dispersion liquid of the lithium ion secondary battery.

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Abstract

This cellulose derivative has a degree of methyl group substitution of 1.0 or higher and a degree of octyl group substitution of from 0.01 to less than 0.6.

Description

セルロース誘導体及びセルロース誘導体溶解液Cellulose derivative and cellulose derivative solution
　本発明は、セルロース誘導体及びセルロース誘導体溶解液に関する。 The present invention relates to a cellulose derivative and a cellulose derivative solution.
　近年、携帯電話やノート型パーソナルコンピュータ等の普及に伴って、リチウムイオン二次電池が注目されている。リチウムイオン二次電池は、通常、炭素材料からなる負極と、リチウムイオンを可逆的に出入りさせる活物質を含有する正極と、それらを浸漬する非水系電解質とを備えている。 In recent years, with the spread of mobile phones, notebook personal computers, etc., lithium ion secondary batteries have been attracting attention. A lithium ion secondary battery usually includes a negative electrode made of a carbon material, a positive electrode containing an active material that reversibly moves lithium ions in and out, and a non-aqueous electrolyte in which they are immersed.
　このうち、正極は、正極活物質、導電材及びバインダからなる電極ペーストを、集電板に塗工することより製造されている。正極活物質としては、リチウム遷移金属複合酸化物等が用いられる。このような正極活物質単独では電子伝導性、即ち導電性に乏しいことから、導電性を付与するために、高度にストラクチャーが発達した導電性カーボンブラック、及び結晶が著しい異方性を示すグラファイト等の炭素材料を導電材として添加し、バインダ（結着材）と共にＮ－メチル－２－ピロリドン（ＮＭＰ）等の非水系溶媒に分散させて、スラリーを作製し、このスラリーを金属箔上に塗布し、乾燥して正極を形成する。 Of these, the positive electrode is manufactured by applying an electrode paste made of a positive electrode active material, a conductive material, and a binder to a current collector plate. As the positive electrode active material, a lithium transition metal composite oxide or the like is used. Since such a positive electrode active material alone has poor electron conductivity, that is, conductivity, conductive carbon black having a highly developed structure in order to impart conductivity, graphite having a crystal showing remarkable anisotropy, etc. Carbon material is added as a conductive material and dispersed in a non-aqueous solvent such as N-methyl-2-pyrrolidone (NMP) together with a binder (binding material) to prepare a slurry, and this slurry is applied onto a metal foil. And dry to form a positive electrode.
　しかしながら、導電材として用いられる炭素材料であるカーボンブラックやグラファイトは一次粒子径が小さい微粉体であり、ストラクチャーや比表面積が大きいため凝集力が強く、リチウムイオン二次電池の電極合材形成用スラリー中に均一混合し分散することが困難である。そして、導電材である炭素材料の分散性や粒度の制御が不十分な場合、均一な導電ネットワークが形成さないために電極の内部抵抗の低減が図れず、その結果、正極活物質であるリチウム遷移金属複合酸化物や炭素材料であるグラファイト等の性能を十分に引き出せないという問題が生じている。また、電極合材中の導電材（導電助剤）の分散が不十分であると、部分的凝集に起因して電極板上に抵抗分布が生じ、電池として使用した際に電流が集中し、部分的な発熱及び劣化が促進される等の不具合が生ずることがある。 However, carbon black and graphite, which are carbon materials used as conductive materials, are fine powders having a small primary particle size, and have a large structure and specific surface area, so that they have strong cohesive force. It is difficult to uniformly mix and disperse in it. If the dispersibility and particle size of the carbon material, which is the conductive material, are not sufficiently controlled, the internal resistance of the electrode cannot be reduced because a uniform conductive network is not formed, and as a result, lithium, which is the positive electrode active material, cannot be reduced. There is a problem that the performance of transition metal composite oxides and graphite, which is a carbon material, cannot be sufficiently brought out. Further, if the conductive material (conductive auxiliary agent) in the electrode mixture is insufficiently dispersed, a resistance distribution is generated on the electrode plate due to partial aggregation, and the current is concentrated when used as a battery. Problems such as partial heat generation and accelerated deterioration may occur.
　導電材を電極中に均一に分散するため、分散剤と共に有機溶剤等の分散媒に分散し、スラリー化させた分散液（導電材分散液）を予め調製し、これを活物質及びバインダと共に混練して電極を形成することが提案されている（特許文献１）。導電助剤の導電性を阻害せずに分散安定化を図り導電助剤の電解液に対する濡れ性を向上させた電池用分散剤が提案されている（特許文献２）。また、良好な分散性および導電性を確保することのできる導電材分散液が提案されている（特許文献３）。そして、分散剤又はバインダに用いられる材料として、Ｎ－メチル－２－ピロリドン（ＮＭＰ）等の極性非水系溶媒に対する溶解性に優れるセルロース系樹脂が知られている（特許文献３）。 In order to uniformly disperse the conductive material in the electrodes, a dispersion liquid (conductive material dispersion liquid) that is dispersed in a dispersion medium such as an organic solvent together with a dispersant and made into a sol is prepared in advance, and this is kneaded together with an active material and a binder. It has been proposed to form an electrode (Patent Document 1). A dispersant for a battery has been proposed in which dispersion stabilization is achieved without impairing the conductivity of the conductive auxiliary agent and the wettability of the conductive auxiliary agent with respect to an electrolytic solution is improved (Patent Document 2). Further, a conductive material dispersion liquid capable of ensuring good dispersibility and conductivity has been proposed (Patent Document 3). As a material used for a dispersant or a binder, a cellulosic resin having excellent solubility in a polar non-aqueous solvent such as N-methyl-2-pyrrolidone (NMP) is known (Patent Document 3).
特開２０１８－１２９３０５号公報JP-A-2018-129305 特開２０１２－１９５２４３号公報Japanese Unexamined Patent Publication No. 2012-195243 特許第５６２８５０３号公報Japanese Patent No. 5628503
　しかしながら、従来のセルロース系樹脂を導電材分散液に含有した場合、その導電材分散液は、チキソトロピー性が高すぎるため、貯蔵安定性が不十分となり、経時的に増粘する等粘度が変化しやすい。このような導電材分散液を活物質及びバインダと共に混練して電極を形成すると、その作業性に劣る。 However, when the conventional cellulosic resin is contained in the conductive material dispersion liquid, the conductive material dispersion liquid has too high thixotropy property, so that the storage stability becomes insufficient and the viscosity such as thickening with time changes. Cheap. When such a conductive material dispersion liquid is kneaded together with an active material and a binder to form an electrode, the workability is inferior.
　本開示は、優れた貯蔵安定性を有するリチウムイオン二次電池の導電材分散液を得ることができるセルロース誘導体を提供することを目的とする。 An object of the present disclosure is to provide a cellulose derivative capable of obtaining a conductive material dispersion liquid of a lithium ion secondary battery having excellent storage stability.
　本開示の第一は、メチル基置換度が１．０以上であり、オクチル基置換度が０．０１以上０．６未満である、セルロース誘導体に関する。 The first of the present disclosure relates to a cellulose derivative having a methyl group substitution degree of 1.0 or more and an octyl group substitution degree of 0.01 or more and less than 0.6.
　前記セルロース誘導体において、前記メチル基置換度及び前記オクチル置換度の和が１．５以上であってよい。 In the cellulose derivative, the sum of the degree of methyl group substitution and the degree of octyl substitution may be 1.5 or more.
　前記セルロース誘導体において、前記オクチル基置換度が０．０６以上０．３未満であってよい。 In the cellulose derivative, the degree of octyl group substitution may be 0.06 or more and less than 0.3.
　本開示の第二は、前記セルロース誘導体及び溶媒を含有し、前記セルロース誘導体の含有量が、前記溶媒１００質量部に対して、０．１質量部以上２０質量部以下であり、前記溶媒が、Ｎ－メチル－２－ピロリドン、及びジメチルアセトアミドよりなる群から選択される１以上を含有する、セルロース誘導体溶解液に関する。 The second aspect of the present disclosure is that the cellulose derivative and the solvent are contained, and the content of the cellulose derivative is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent. The present invention relates to a cellulose derivative solution containing one or more selected from the group consisting of N-methyl-2-pyrrolidone and dimethylacetamide.
　本開示のセルロース誘導体によれば、優れた貯蔵安定性を有するリチウムイオン二次電池の導電材分散液を得ることができる。 According to the cellulose derivative of the present disclosure, it is possible to obtain a conductive material dispersion liquid of a lithium ion secondary battery having excellent storage stability.
　＜セルロース誘導体＞
　本開示のセルロース誘導体は、メチル基置換度が１．０以上であり、オクチル基置換度が０．０１以上０．６未満である。 <Cellulose derivative>
The cellulose derivative of the present disclosure has a methyl group substitution degree of 1.0 or more and an octyl group substitution degree of 0.01 or more and less than 0.6.
　また、本開示のセルロース誘導体は、いいかえれば、水酸基の水素の一部又はすべてが、メチル基及びオクチル基に置換されたセルロースである。 In other words, the cellulose derivative of the present disclosure is cellulose in which some or all of the hydrogen of the hydroxyl group is substituted with a methyl group and an octyl group.
　セルロース誘導体のメチル基置換度は、１．０以上であるところ、１．５以上であってよく、１．８以上であってよい。また、セルロース誘導体のメチル基置換度は、２．９９未満であってよく、２．９４以下であってよく、２．９以下であってよく、２．５以下であってよく、２．４以下であってよく、２．０以下であってよい。セルロース誘導体のメチル基置換度が小さすぎると、ＮＭＰ等の極性非水系溶媒への溶解性に劣り、導電材を分散できない。メチル基置換度が大きすぎると、セルロース誘導体製造時のオクチル基導入が難しくなる。 The degree of methyl group substitution of the cellulose derivative is 1.0 or more, may be 1.5 or more, and may be 1.8 or more. Further, the degree of methyl group substitution of the cellulose derivative may be less than 2.99, may be 2.94 or less, may be 2.9 or less, may be 2.5 or less, and may be 2.4. It may be less than or equal to, and may be less than or equal to 2.0. If the degree of methyl group substitution of the cellulose derivative is too small, the solubility in a polar non-aqueous solvent such as NMP is poor, and the conductive material cannot be dispersed. If the degree of methyl group substitution is too large, it becomes difficult to introduce an octyl group during the production of a cellulose derivative.
　セルロース誘導体のオクチル基置換度は、０．０１以上であるところ、０．０６以上であってよく、０．０８以上であってよく、０．１以上であってよく、０．２以上であってよい。また、オクチル基置換度は、０．６未満であるところ、０．５未満であってよく、０．４未満であってよく、０．３未満であってよい。セルロース誘導体のオクチル基置換度が小さすぎると、当該セルロース誘導体を含有する導電材分散液は、チキソトロピー性が高く、経時的に増粘しやすく、貯蔵安定性が不十分である。セルロース誘導体のオクチル基置換度が大きすぎると、当該セルロース誘導体を含有する導電材分散液は貯蔵安定性が不十分であるだけでなく、極性溶媒への溶解性に劣り、非水系電解質の溶媒（非極性溶媒）に対する耐溶解性に劣る。非水系電解質の溶媒（非極性溶媒）に対する耐溶解性により優れる観点からは、オクチル基置換度は０．０６以上０．３未満が好ましい。 The degree of octyl group substitution of the cellulose derivative is 0.01 or more, may be 0.06 or more, may be 0.08 or more, may be 0.1 or more, and may be 0.2 or more. It's okay. Further, the degree of octyl group substitution may be less than 0.5, less than 0.4, and less than 0.3, where it is less than 0.6. If the degree of octyl group substitution of the cellulose derivative is too small, the conductive material dispersion liquid containing the cellulose derivative has high thixotropy property, tends to thicken with time, and has insufficient storage stability. If the degree of octyl group substitution of the cellulose derivative is too large, the conductive material dispersion containing the cellulose derivative will not only have insufficient storage stability, but will also be inferior in solubility in a polar solvent, resulting in a solvent for a non-aqueous electrolyte (a solvent for a non-aqueous electrolyte). Poor solubility in non-polar solvents). From the viewpoint of being more excellent in the solubility of the non-aqueous electrolyte in a solvent (non-polar solvent), the octyl group substitution degree is preferably 0.06 or more and less than 0.3.
　セルロース誘導体のメチル基置換度とオクチル基置換度の和は、１．５以上が好ましく、１．７以上であってよく、２．０以上であってよい。また、その和は、３．０未満であってよく、２．９未満であってよく、２．６未満であってよい。 The sum of the degree of methyl group substitution and the degree of octyl group substitution of the cellulose derivative is preferably 1.5 or more, preferably 1.7 or more, and may be 2.0 or more. The sum may be less than 3.0, less than 2.9, and less than 2.6.
　セルロース誘導体の各置換基の置換度の和を総置換度といい、セルロース誘導体の総置換度は、１．５以上であってよく、１．７以上であってよく、２．０以上であってよい。また、総置換度の最大値は３．０であるところ、その総置換度は、３．０未満であってよく、２．９未満であってよく、２．６未満であってよい。 The sum of the degrees of substitution of each substituent of the cellulose derivative is called the total degree of substitution, and the total degree of substitution of the cellulose derivative may be 1.5 or more, 1.7 or more, and 2.0 or more. It's okay. Further, where the maximum value of the total substitution degree is 3.0, the total substitution degree may be less than 3.0, less than 2.9, and less than 2.6.
　メチル基置換度及びオクチル基置換度を含むアルキル基置換度は、以下の方法により測定することができる。ＡＳＴＭ：Ｄ－８１７－９１に準ずる方法や、１３Ｃ－ＮＭＲ、１Ｈ－ＮＭＲにより測定できる。 The degree of alkyl group substitution including the degree of methyl group substitution and the degree of octyl group substitution can be measured by the following method. It can be measured by a method according to ASTM: D-817-91, 13 C-NMR, and 1 H-NMR.
　セルロース誘導体のメチル基置換度及びオクチル基置換度を１Ｈ－ＮＭＲにより定量する場合の条件の例を以下に記載する。 Examples of conditions for quantifying the degree of methyl group substitution and the degree of octyl group substitution of the cellulose derivative by 1 H-NMR are described below.
装置：ＪＥＯＬ　ＪＮＭ　ＥＣＡ－５００
温度：８０℃
溶媒：ＤＭＳＯ
試料濃度：０．８ｗｔ％
計算：
　メチル基置換度＝３５β／（１５α－１５β－２γ）
　オクチル基置換度＝７γ／（１５α－１５β－２γ）
　　α：５．４０～２．７０ｐｐｍの積分値
　　β：３．５１～３．４１、３．３２～３．２５ｐｐｍの積分値
　　γ：１．６５～０．７０ｐｐｍの積分値 Equipment: JEOL JNM ECA-500
Temperature: 80 ° C
Solvent: DMSO
Sample concentration: 0.8 wt%
Calculation:
Methyl group substitution degree = 35β / (15α-15β-2γ)
Octyl group substitution degree = 7γ / (15α-15β-2γ)
α: Integral value of 5.40 to 2.70 ppm β: Integral value of 3.51 to 3.41, 3.32 to 3.25 ppm Integral value γ: Integral value of 1.65 to 0.70 ppm
　セルロース誘導体の重量平均分子量（Ｍｗ）は、特に限定されるものではないが、１．０×１０４以上が好ましく、２．０×１０４以上がより好ましく、３．０×１０４以上がさらに好ましい。また、当該重量平均分子量は、１．０×１０６以下が好ましく、５．０×１０５以下がより好ましく、２．０×１０５以下がさらに好ましい。当該範囲であることにより、導電材分散液におけるセルロース誘導体の分散性、及び分散液製造時の作業性が良好なものとなる。 The weight average molecular weight of the cellulose derivative (Mw) of, but are not limited to, preferably 1.0 × 10 4 or more, 2.0 × more preferably 10 4 or more, 3.0 × 10 4 or more preferable. Further, the weight average molecular weight is preferably from 1.0 × 10 6 or less, more preferably 5.0 × 10 5 or less, more preferably 2.0 × 10 5 or less. Within this range, the dispersibility of the cellulose derivative in the conductive material dispersion liquid and the workability at the time of producing the dispersion liquid are improved.
　重量平均分子量は、個々の分子の重量にその分子量を掛けて平均値を求める、いわゆる分子量の加重平均値であり、ＧＰＣで測定できる。 The weight average molecular weight is a so-called weighted average value of molecular weight, which is obtained by multiplying the weight of each molecule by the molecular weight to obtain an average value, and can be measured by GPC.
　本開示のセルロース誘導体によれば、チキソトロピー性が高くなりすぎず、優れた貯蔵安定性を有するリチウムイオン二次電池の導電材分散液を得ることができる。 According to the cellulose derivative of the present disclosure, it is possible to obtain a conductive material dispersion liquid of a lithium ion secondary battery having excellent storage stability without excessively high thixotropy.
　セルロース誘導体は、例えば、以下のようにして製造することができる。セルロース原料を塩基性条件下でアルカリセルロースにする工程（活性化工程）；及び前記アルカリセルロースをハロゲン化アルキルと反応させる工程（エーテル化処理）を含む製造方法が挙げられる。 The cellulose derivative can be produced, for example, as follows. Examples thereof include a production method including a step of converting a cellulose raw material into alkaline cellulose under basic conditions (activation step); and a step of reacting the alkali cellulose with an alkyl halide (etherification treatment).
　より具体的には、例えば、セルロース原料を水酸化ナトリウムによりマーセル化して、アルカリセルロースにする工程；前記アルカリセルロースをメチル化剤と反応させてエーテル化することにより、メチルセルロースを得る工程；その後、塩基性条件下、前記メチルセルロースをオクチル化剤と反応させてエーテル化することにより、メチルオクチルセルロース（セルロース誘導体）を得る工程を有する製造方法（二段階反応と称する）が挙げられる。また、前記アルカリセルロースをメチル化剤及びオクチル化剤の両方と反応させてエーテル化することにより、メチルオクチルセルロース（セルロース誘導体）を得ることもできる（一段階反応と称する）。メチル化剤及びオクチル化剤の配合量及び配合割合は任意に選択できる。 More specifically, for example, a step of marcelifying a cellulose raw material with sodium hydroxide to obtain alkali cellulose; a step of reacting the alkali cellulose with a methylating agent to etherify it to obtain methyl cellulose; and then a base. Examples thereof include a production method (referred to as a two-step reaction) having a step of obtaining methyl octyl cellulose (cellulose derivative) by reacting the methyl cellulose with an octylizing agent to etherify it under sexual conditions. Further, methyloctyl cellulose (cellulose derivative) can also be obtained by reacting the alkaline cellulose with both a methylating agent and an octylizing agent to etherify it (referred to as a one-step reaction). The blending amount and blending ratio of the methylating agent and the octylling agent can be arbitrarily selected.
　メチルオクチルセルロース（セルロース誘導体）のメチル基及びオクチル基の置換度を精度よく調整するため、メチルセルロースを得た後、前記メチルセルロースをオクチル化剤と反応させてエーテル化することにより、メチルオクチルセルロース（セルロース誘導体）を得る工程を有する製造方法（二段階反応）が好ましい。 In order to accurately adjust the degree of substitution of the methyl group and the octyl group of methyl octyl cellulose (cellulose derivative), after obtaining methyl cellulose, the methyl cellulose is reacted with an octylizing agent to etherify the methyl octyl cellulose (cellulose). A production method (two-step reaction) having a step of obtaining a derivative) is preferable.
　メチル化剤としては、メチルクロライド等のハロゲン化メチルが、また、オクチル化剤としては、オクチルクロライド等のハロゲン化オクチルが挙げられる。 Examples of the methylating agent include methyl halides such as methyl chloride, and examples of the octylizing agent include octyl halides such as octyl chloride.
　＜セルロース誘導体溶解液＞
　本開示のセルロース誘導体溶解液は、前記セルロース誘導体及び溶媒を含有し、前記セルロース誘導体の含有量が、前記溶媒１００質量部に対して、０．１質量部以上２０質量部以下である。 <Cellulose derivative solution>
The cellulose derivative solution of the present disclosure contains the cellulose derivative and the solvent, and the content of the cellulose derivative is 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent.
　セルロース誘導体溶解液は、溶媒中に、セルロース誘導体が溶解した液であり、溶解した液であるどうかは目視で観察する。セルロース誘導体の固形物、膨潤体、及びゲル状体等の形状が観察される場合は溶解液とはいえない。これらの形状が確認できず透明である場合は溶解液である。 The cellulose derivative solution is a solution in which the cellulose derivative is dissolved in a solvent, and it is visually observed whether or not the solution is a solution. When the shape of a solid substance, a swollen body, a gel-like body, or the like of a cellulose derivative is observed, it cannot be said to be a solution. If these shapes cannot be confirmed and are transparent, it is a solution.
　セルロース誘導体溶解液の溶媒としては、例えば、Ｎ－メチルピロリドン、Ｎ－エチルピロリドン、Ｎ，Ｎ－ジメチルホルムアミド、テトラヒドロフラン、ジメチルアセトアミド、ジメチルスルホキシド、ヘキサメチルスルホルアミド、テトラメチル尿素、アセトン、メチルエチルケトン、Ｎ－メチルピロリドンとエステル系溶媒（例えば、酢酸エチル、酢酸ｎ－ブチル、ブチルセロソルブアセテート、及びブチルカルビトールアセテート等）の混合溶媒、並びにＮ－メチルピロリドンとグライム系溶媒（例えば、ジグライム、トリグライム、及びテトラグライム等）の混合溶液の混合溶媒等が挙げられる。これらのうち、Ｎ－メチル－２－ピロリドン、及びジメチルアセトアミドよりなる群から選択される１以上を含有する溶媒が好ましい。比較的揮発性が高く、多くの有機溶剤と混合しやすく扱いやすい。そのため、電極材料のスラリーが安定的に作成可能である。 Examples of the solvent for the cellulose derivative solution include N-methylpyrrolidone, N-ethylpyrrolidone, N, N-dimethylformamide, tetrahydrofuran, dimethylacetamide, dimethylsulfoxide, hexamethylsulfolamide, tetramethylurea, acetone, and methylethylketone. A mixed solvent of N-methylpyrrolidone and an ester solvent (for example, ethyl acetate, n-butyl acetate, butyl cellosolve acetate, and butyl carbitol acetate, etc.), and an N-methylpyrrolidone and a glyme-based solvent (for example, diglime, triglime, and the like). Examples thereof include a mixed solvent of a mixed solution of (tetraglyme, etc.). Of these, a solvent containing one or more selected from the group consisting of N-methyl-2-pyrrolidone and dimethylacetamide is preferable. It is relatively volatile and easy to mix with many organic solvents and easy to handle. Therefore, a slurry of electrode materials can be stably produced.
　セルロース誘導体溶解液におけるセルロース誘導体の含有量は、溶媒１００質量部に対して、０．１質量部以上２０質量部以下であるところ、０．１質量部以上１０質量部以下が好ましく、０．１質量部以上５以下がより好ましい。 The content of the cellulose derivative in the cellulose derivative solution is 0.1 parts by mass or more and 20 parts by mass or less, preferably 0.1 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the solvent. More preferably, it is 5 parts by mass or more.
　本開示のセルロース誘導体溶解液のチキソトロピーインデックス値は１０未満が好ましく、５未満がより好ましい。また、１以上であってよい。 The thixotropy index value of the cellulose derivative solution of the present disclosure is preferably less than 10, more preferably less than 5. Moreover, it may be 1 or more.
　チキソトロピーインデックス値とは、加えた力が大きくなるにつれ、粘度が下がるチキソトロピー性の指標である。その数値が大きいほどチキソトロピー性が高い。 The thixotropy index value is an index of thixotropy in which the viscosity decreases as the applied force increases. The larger the value, the higher the thixotropy.
　また、チキソトロピーインデックス値は、以下の方法により測定することができる。まず、９５質量部のＮＭＰに対し、５質量部の試料を溶解してＮＭＰ溶液を調製し、以下の（１）～（４）の装置及び条件下にて、回転速度０．５ｒｐｍでの粘度、及び回転速度５０ｒｐｍでの粘度求める。
（１）装置：ＴＶ－２２（東機産業（株）社製）
（２）測定治具：コーンプレート（１°３４' × Ｒ２４）、
（３）温度：２５℃
（４）回転速度：０．５ｒｐｍ、５０ｒｐｍ The thixotropy index value can be measured by the following method. First, 5 parts by mass of a sample is dissolved in 95 parts by mass of NMP to prepare an NMP solution, and the viscosity at a rotation speed of 0.5 rpm under the following devices and conditions (1) to (4). , And the viscosity at a rotation speed of 50 rpm.
(1) Equipment: TV-22 (manufactured by Toki Sangyo Co., Ltd.)
(2) Measuring jig: Cone plate (1 ° 34'x R24),
(3) Temperature: 25 ° C
(4) Rotation speed: 0.5 rpm, 50 rpm
　次に、回転速度０．５ｒｐｍでの粘度／回転速度５０ｒｐｍでの粘度をチキソトロピーインデックス値（ＴＩ値）として算出する。 Next, the viscosity at a rotation speed of 0.5 rpm / the viscosity at a rotation speed of 50 rpm is calculated as a thixotropy index value (TI value).
　［用途］
　本開示のセルロース誘導体は、極性非水系溶媒に対する優れた溶解性、及び非水系電解質の溶媒（非極性溶媒）に対する優れた耐溶解性を両立するため、リチウムイオン二次電池正極用の導電材分散液等のリチウムイオン二次電池正極を構成する材料として好適に用いられる。非水系電解質の溶媒（非極性溶媒）に対する優れた耐溶解性は、リチウムイオン二次電池の使用時、充放電による容量の低下を抑制し、サイクル特性を向上する等、リチウムイオン二次電池の性能向上に寄与する。 [Use]
The cellulose derivative of the present disclosure has both excellent solubility in a polar non-aqueous solvent and excellent solubility resistance in a non-aqueous electrolyte solvent (non-polar solvent), so that a conductive material is dispersed for the positive electrode of a lithium ion secondary battery. It is suitably used as a material for forming a positive electrode of a lithium ion secondary battery such as a liquid. The excellent solubility resistance of non-aqueous electrolytes to solvents (non-polar solvents) suppresses the decrease in capacity due to charging and discharging when using lithium-ion secondary batteries, and improves cycle characteristics. Contributes to performance improvement.
　本開示のセルロース誘導体溶解液を、例えば、導電材、分散剤、及び分散媒等と共に混合することによりリチウムイオン二次電池正極用の導電材分散液を調製することがきる。リチウムイオン二次電池正極用の導電材分散液は、例えば、本開示のセルロース誘導体溶解液、を含有する。 It is possible to prepare a conductive material dispersion liquid for a positive electrode of a lithium ion secondary battery by mixing the cellulose derivative dissolution liquid of the present disclosure together with, for example, a conductive material, a dispersant, a dispersion medium and the like. The conductive material dispersion liquid for the positive electrode of the lithium ion secondary battery contains, for example, the cellulose derivative dissolution liquid of the present disclosure.
　導電材としては、従来公知の物質を用いることができ、例えば、カーボンブラック及びカーボンナノチューブ等が挙げられる。 As the conductive material, conventionally known substances can be used, and examples thereof include carbon black and carbon nanotubes.
　分散剤としては、例えば、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン、ポリヘキサフルオロプロピレン、ポリエチレン、ポリプロピレン、ポリメタクリル酸メチル、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリ酢酸ビニル、ポリアクリル酸、ポリビニルブチラール、ポリアクリルアミド、ポリウレタン、ポリジメチルシロキサン、エポキシ樹脂、アクリル樹脂、ポリエステル樹脂、メラミン樹脂、フェノール樹脂、各種ゴム、リグニン、ペクチン、ゼラチン、キサンタンガム、ウェランガム、サクシノグリカン、ポリビニルアルコール、ポリビニルアセタール、セルロース系樹脂（メチルオクチルセルロースを除く）、ポリアルキレンオキサイド、ポリビニルエーテル、ポリビニルピロリドン、キチン類、キトサン類、及びデンプン等の有機材料の非イオン性分散剤、並びに、ガラス、アルミナ、シリカ、セラミックス、ロックウール等の無機材料の非イオン性分散剤等が挙げられる。 Examples of the dispersant include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polyhexafluoropropylene, polyethylene, polypropylene, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid, and polyvinyl. Butyral, polyacrylamide, polyurethane, polydimethylsiloxane, epoxy resin, acrylic resin, polyester resin, melamine resin, phenol resin, various rubbers, lignin, pectin, gelatin, xanthan gum, welan gum, succinoglycan, polyvinyl alcohol, polyvinyl acetal, cellulose Nonionic dispersants for organic materials such as based resins (excluding methyloctyl cellulose), polyalkylene oxides, polyvinyl ethers, polyvinylpyrrolidones, chitins, chitosans, and starch, as well as glass, alumina, silica, ceramics, and locks. Examples thereof include nonionic dispersants for inorganic materials such as wool.
　分散媒としては、例えば、ペンタン、ノルマルヘキサン、オクタン、シクロペンタン、及びシクロヘキサン等の脂肪族炭化水素系分散媒；ベンゼン、トルエン、キシレン、及びシメン等の芳香族炭化水素系分散媒；フルフラル等のアルデヒド系分散媒；アセトン、メチルエチルケトン、シクロペンタノン、及びシクロヘキサノン等のケトン系分散媒；酢酸ブチル、酢酸エチル、酢酸メチル、ブチルプロピオネート、エチレングリコールモノエチルエーテルアセテート、プロピレングリコールモノメチルエーテルアセテート、３－メトキシブチルアセテート、及びエチレングリコールジアセテート等のエステル系分散媒；テトラヒドロフラン、ジオキサン、及びエチレングリコールジメチルエーテル等のエーテル系分散媒；メタノール、エタノール、ノルマルプロピルアルコール、イソプロピルアルコール、ブチルアルコール、オクチルアルコール、シクロヘキサノール、アリルアルコール、ベンジルアルコール、クレゾール、及びフルフリルアルコール等のアルコール系分散媒；グリセロール、エチレングリコール、及びジエチレングリコール等のポリオール系分散媒；エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノブチルエーテル、プロピレングリコールモノメチルエーテル、及びジエチレングリコールモノブチルエーテル等のアルコールエーテル系分散媒；Ｎ－メチル－２－ピロリドン（ＮＭＰ）、ジメチルスルホキシド、及びジメチルホルムアミド等の非プロトン性極性分散媒；並びに水等が挙げられる。 Examples of the dispersion medium include aliphatic hydrocarbon-based dispersion media such as pentane, normal hexane, octane, cyclopentane, and cyclohexane; aromatic hydrocarbon-based dispersion media such as benzene, toluene, xylene, and simene; and furfural and the like. Alcohol-based dispersion medium; Ketone-based dispersion medium such as acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone; butyl acetate, ethyl acetate, methyl acetate, butyl propionate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, 3 -Ester-based dispersion media such as methoxybutyl acetate and ethylene glycol diacetate; ether-based dispersion media such as tetrahydrofuran, dioxane, and ethylene glycol dimethyl ether; methanol, ethanol, normal propyl alcohol, isopropyl alcohol, butyl alcohol, octyl alcohol, cyclo Alcohol-based dispersion media such as hexanol, allyl alcohol, benzyl alcohol, cresol, and furfuryl alcohol; polyol-based dispersion media such as glycerol, ethylene glycol, and diethylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether , Alcohol ether-based dispersion media such as propylene glycol monomethyl ether, and diethylene glycol monobutyl ether; aprotonic polar dispersion media such as N-methyl-2-pyrrolidone (NMP), dimethylsulfoxide, and dimethylformamide; and water. ..
　以下、実施例に基づいて本開示を詳述するが、これらの実施例によってその技術的範囲が限定されるものではない。 Hereinafter, the present disclosure will be described in detail based on examples, but the technical scope is not limited by these examples.
　実施例及び比較例における各種の測定は、以下の方法により行った。
　＜置換度＞
　アルキル基置換度（メチル基置換度及びオクチル置換度）は、以下の条件にて、１Ｈ－ＮＭＲにより定量した。
　装置：ＪＥＯＬ　　ＪＮＭ　　ＥＣＡ－５００
　温度：８０℃
　溶媒：ＤＭＳＯ
　試料濃度：０．８ｗｔ％
計算：
　メチル基置換度＝３５β／（１５α－１５β－２γ）
　オクチル基置換度＝７γ／（１５α－１５β－２γ）
　　α：５．４０～２．７０ｐｐｍの積分値
　　β：３．５１～３．４１、３．３２～３．２５ｐｐｍの積分値
　　γ：１．６５～０．７０ｐｐｍの積分値 Various measurements in Examples and Comparative Examples were carried out by the following methods.
<Degree of substitution>
The degree of alkyl group substitution (degree of methyl group substitution and degree of octyl substitution) was quantified by 1 H-NMR under the following conditions.
Equipment: JEOL JNM ECA-500
Temperature: 80 ° C
Solvent: DMSO
Sample concentration: 0.8 wt%
Calculation:
Methyl group substitution degree = 35β / (15α-15β-2γ)
Octyl group substitution degree = 7γ / (15α-15β-2γ)
α: Integral value of 5.40 to 2.70 ppm β: Integral value of 3.51 to 3.41, 3.32 to 3.25 ppm Integral value γ: Integral value of 1.65 to 0.70 ppm
　＜溶媒溶解性の評価＞
　３００ｍｌビーカーに所定の溶媒２００ｇを採取し、室温（２５℃）もしくは８０℃加温下、マグネチックスターラーにて撹拌しているところに試料２ｇを添加した。その後の状態を目視で観察して以下の基準にて、各溶媒に対する溶解性を評価した。溶媒は、極性溶媒として、Ｎ－メチル－２－ピロリドン（ＮＭＰ）及びジメチルアセトアミド（ＤＭＡｃ）、非極性溶媒として、ヘキサン、トルエン及びキシレンを用いた。
◎：室温で容易に完全溶解
〇：８０℃に加温することで完全に溶解
△：８０℃に加温しても膨潤またはゲル化
×：８０℃に加温しても不溶 <Evaluation of solvent solubility>
200 g of the predetermined solvent was collected in a 300 ml beaker, and 2 g of the sample was added to the place where the mixture was stirred at room temperature (25 ° C.) or 80 ° C. with a magnetic stirrer. The subsequent state was visually observed and the solubility in each solvent was evaluated according to the following criteria. As the solvent, N-methyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAc) were used as polar solvents, and hexane, toluene and xylene were used as non-polar solvents.
⊚: Easy complete dissolution at room temperature 〇: Completely dissolved by heating to 80 ° C Δ: Swelling or gelation even when heated to 80 ° C ×: Insoluble even when heated to 80 ° C
　＜チキソトロピー性の評価＞
　まず、６０℃下、９５質量部のＮＭＰに対し、５質量部の試料を溶解してＮＭＰ溶液を調製し、以下の（１）～（４）の装置及び条件にて、回転速度０．５ｒｐｍでの粘度、及び回転速度５０ｒｐｍでの粘度求めた。
（１）装置：ＴＶ－２２（東機産業（株）社製）
（２）測定治具：コーンプレート（１°３４' × Ｒ２４）、
（３）温度：２５℃
（４）回転速度：０．５ｒｐｍ、５０ｒｐｍ <Evaluation of thixotropy>
First, at 60 ° C., 5 parts by mass of a sample was dissolved in 95 parts by mass of NMP to prepare an NMP solution, and the rotation speed was 0.5 rpm under the following devices and conditions (1) to (4). And the viscosity at a rotation speed of 50 rpm were determined.
(1) Equipment: TV-22 (manufactured by Toki Sangyo Co., Ltd.)
(2) Measuring jig: Cone plate (1 ° 34'x R24),
(3) Temperature: 25 ° C
(4) Rotation speed: 0.5 rpm, 50 rpm
　次に、回転速度０．５ｒｐｍでの粘度／回転速度５０ｒｐｍでの粘度をチキソトロピーインデックス値（ＴＩ値）として算出し、以下の基準でチキソトロピー性を評価した。
◎：上記ＴＩ値が５未満
○：上記ＴＩ値が５以上１０未満
×：上記ＴＩ値が１０以上 Next, the viscosity at a rotation speed of 0.5 rpm / the viscosity at a rotation speed of 50 rpm was calculated as a thixotropy index value (TI value), and the thixotropy property was evaluated according to the following criteria.
⊚: The TI value is less than 5 ○: The TI value is 5 or more and less than 10 ×: The TI value is 10 or more
　＜メチルセルロースの合成＞
　（ＭＣ－１）
　２Ｌの撹拌機付きオートクレーブに解砕パルプ１００ｇ、水酸化ナトリウム水溶液（水酸化ナトリウム（ＮａＯＨ）７５ｇ、水１５０ｍｌ）を加え、窒素雰囲気下、４５℃で１時間撹拌した（第一工程）。放冷後、ドライアイス／メタノールバスで－４０℃に冷却し、さらにトルエン１５０ｍｌ、クロロメタン１２０ｇ、６０℃（反応温度（１））で１時間（反応時間（１））、その後１００℃（反応温度（２））で３時間（反応時間（２））撹拌した（第二工程）。室温に戻した後、系内の残存ガスを排気し、メタノール１２Ｌ中へ激しく撹拌しながら投入し白色固体を得た（第三工程）。白色固体を吸引濾過により濾別し、大量のイソプロピルアルコールで３回洗浄を行った。得られた白色固体を１００℃で６時間真空乾燥することによりメチルセルロース（ＭＣ－１）を白色粉末として得た（収量９８ｇ）。メチルセルロース（ＭＣ－１）のメチル基置換度を表１に示す。 <Synthesis of methyl cellulose>
(MC-1)
100 g of crushed pulp and an aqueous sodium hydroxide solution (75 g of sodium hydroxide (NaOH), 150 ml of water) were added to a 2 L autoclave with a stirrer, and the mixture was stirred at 45 ° C. for 1 hour under a nitrogen atmosphere (first step). After allowing to cool, the mixture is cooled to −40 ° C. in a dry ice / methanol bath, and further, 150 ml of toluene, 120 g of chloromethane, 60 ° C. (reaction temperature (1)) for 1 hour (reaction time (1)), and then 100 ° C. (reaction) Stirring at temperature (2)) for 3 hours (reaction time (2)) (second step). After returning to room temperature, the residual gas in the system was exhausted and poured into 12 L of methanol with vigorous stirring to obtain a white solid (third step). The white solid was filtered off by suction filtration and washed 3 times with a large amount of isopropyl alcohol. The obtained white solid was vacuum dried at 100 ° C. for 6 hours to obtain methyl cellulose (MC-1) as a white powder (yield 98 g). The degree of methyl group substitution of methyl cellulose (MC-1) is shown in Table 1.
　（ＭＣ－２～５）
　第一工程及び第二工程における各条件を表１のとおり換えた以外は、ＭＣ－１の合成と同様にして、各メチルセルロース（ＭＣ－２、ＭＣ－３、ＭＣ－４及びＭＣ－５）を得た。各メチルセルロースのメチル基置換度を表１に示す。 (MC-2-5)
Each methyl cellulose (MC-2, MC-3, MC-4 and MC-5) was prepared in the same manner as in the synthesis of MC-1 except that the conditions in the first step and the second step were changed as shown in Table 1. Obtained. The degree of methyl group substitution of each methyl cellulose is shown in Table 1.
　（ＭＣ－６）
　ＭＣ－６として、メチルセルロース（信越化学工業（株）製）を用いた。 (MC-6)
Methyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as MC-6.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
　＜メチルオクチルセルロースの合成＞
　（実施例１）
　２Ｌの撹拌機付きオートクレーブに、原料としてメチルセルロース（ＭＣ－５）１００ｇ、４８％水酸化ナトリウム水溶液１３０ｇを添加した。室温で１時間攪拌した後、トルエン５００ｍＬ、オクチルクロライド４８０ｇを添加し、室温で３０分攪拌した。さらに１３０℃（反応温度）で１０時間（反応時間）攪拌し、反応終了後、室温に戻した。白色固体を吸引ろ過によりろ別した後、大量のイソプロピルアルコールで３回洗浄を行った。得られた白色固体を１００℃で６時間真空乾燥することによりメチルオクチルセルロースを白色粉末として得た（収量１０１ｇ）。 <Synthesis of methyloctyl cellulose>
(Example 1)
To a 2 L autoclave with a stirrer, 100 g of methyl cellulose (MC-5) and 130 g of a 48% sodium hydroxide aqueous solution were added as raw materials. After stirring at room temperature for 1 hour, 500 mL of toluene and 480 g of octyl chloride were added, and the mixture was stirred at room temperature for 30 minutes. Further, the mixture was stirred at 130 ° C. (reaction temperature) for 10 hours (reaction time), and after the reaction was completed, the temperature was returned to room temperature. The white solid was filtered by suction filtration and then washed 3 times with a large amount of isopropyl alcohol. The obtained white solid was vacuum dried at 100 ° C. for 6 hours to obtain methyloctyl cellulose as a white powder (yield 101 g).
　得られたメチルオクチルセルロースについて、各物性を評価した結果は、表３に示す。 Table 3 shows the results of evaluating each physical property of the obtained methyloctyl cellulose.
　（実施例２～１０、比較例７～１３）
　原料、オクチルクロライド量、４８％水酸化ナトリウム水溶液量、及び反応温度及び反応時間を、表２のとおり換えた以外は、実施例１と同様にして、各メチルオクチルセルロースを得た。得られたメチルオクチルセルロースについて、各物性を評価した結果は、表３に示す。 (Examples 2 to 10, Comparative Examples 7 to 13)
Each methyloctyl cellulose was obtained in the same manner as in Example 1 except that the raw material, the amount of octyl chloride, the amount of 48% aqueous sodium hydroxide solution, and the reaction temperature and reaction time were changed as shown in Table 2. Table 3 shows the results of evaluating each physical property of the obtained methyloctyl cellulose.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　（比較例１～６）
　表２に示す各メチルセルロース（ＭＣ－１、ＭＣ－２、ＭＣ－３、ＭＣ－４、ＭＣ－５及びＭＣ－６）の各物性を評価した結果は、表３に示す。 (Comparative Examples 1 to 6)
The results of evaluating the physical characteristics of each of the methyl celluloses (MC-1, MC-2, MC-3, MC-4, MC-5 and MC-6) shown in Table 2 are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３に示すように、実施例のセルロース誘導体によれば、チキソトロピーインデックス値が高くなりすぎず、優れた貯蔵安定性を有するセルロース誘導体溶解液が得られることが分かる。また、実施例のセルロース誘導体は、極性非水系溶媒に対する優れた溶解性、及び非水系電解質の溶媒（非極性溶媒）に対する優れた耐溶解性を有することが示され、リチウムイオン二次電池正極及びリチウムイオン二次電池の導電材分散液を構成する材料として好適であることが分かる。 As shown in Table 3, according to the cellulose derivative of the example, it can be seen that the thixotropy index value does not become too high and a cellulose derivative solution having excellent storage stability can be obtained. Further, it was shown that the cellulose derivative of the example has excellent solubility in a polar non-aqueous solvent and excellent solubility resistance in a solvent (non-polar solvent) of a non-aqueous electrolyte. It can be seen that it is suitable as a material constituting the conductive material dispersion liquid of the lithium ion secondary battery.

Claims (4)

  1. 　メチル基置換度が１．０以上であり、
    オクチル基置換度が０．０１以上０．６未満である、セルロース誘導体。     The degree of methyl group substitution is 1.0 or more,
    A cellulose derivative having an octyl group substitution degree of 0.01 or more and less than 0.6.
  2. 　前記メチル基置換度及び前記オクチル置換度の和が１．５以上である、請求項１に記載のセルロース誘導体。 The cellulose derivative according to claim 1, wherein the sum of the degree of methyl group substitution and the degree of octyl substitution is 1.5 or more.
  3. 　前記オクチル基置換度が０．０６以上０．３未満である、請求項１又は２に記載のセルロース誘導体。 The cellulose derivative according to claim 1 or 2, wherein the degree of octyl group substitution is 0.06 or more and less than 0.3.
  4. 　請求項１～３のいずれか一項に記載のセルロース誘導体及び溶媒を含有し、
    前記セルロース誘導体の含有量が、前記溶媒１００質量部に対して、０．１質量部以上２０質量部以下であり、
    前記溶媒が、Ｎ－メチル－２－ピロリドン、及びジメチルアセトアミドよりなる群から選択される１以上を含有する、セルロース誘導体溶解液。     Contains the cellulose derivative and solvent according to any one of claims 1 to 3.
    The content of the cellulose derivative is 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the solvent.
    A cellulose derivative solution containing one or more selected from the group consisting of N-methyl-2-pyrrolidone and dimethylacetamide as the solvent.
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