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WO2018070473A1 - Épaississant utilisé dans un liquide de revêtement pour séparateurs de batterie, liquide de revêtement pour séparateurs de batterie, et séparateur de batterie - Google Patents

Épaississant utilisé dans un liquide de revêtement pour séparateurs de batterie, liquide de revêtement pour séparateurs de batterie, et séparateur de batterie Download PDF

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Publication number
WO2018070473A1
WO2018070473A1 PCT/JP2017/036998 JP2017036998W WO2018070473A1 WO 2018070473 A1 WO2018070473 A1 WO 2018070473A1 JP 2017036998 W JP2017036998 W JP 2017036998W WO 2018070473 A1 WO2018070473 A1 WO 2018070473A1
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WIPO (PCT)
Prior art keywords
battery separator
coating liquid
fibrous cellulose
mass
thickener
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Ceased
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PCT/JP2017/036998
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English (en)
Japanese (ja)
Inventor
裕一 野口
郁絵 本間
孟晨 趙
雄右 轟
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Oji Holdings Corp
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Oji Holdings Corp
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Priority to JP2018507750A priority Critical patent/JP6390815B2/ja
Publication of WO2018070473A1 publication Critical patent/WO2018070473A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B15/00—Preparation of other cellulose derivatives or modified cellulose, e.g. complexes
    • C08B15/08—Fractionation of cellulose, e.g. separation of cellulose crystallites
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B5/00—Preparation of cellulose esters of inorganic acids, e.g. phosphates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/429—Natural polymers
    • H01M50/4295—Natural cotton, cellulose or wood
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/44—Fibrous material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • 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 thickener for battery separator coating liquid, a battery separator coating liquid, and a battery separator.
  • Lithium ion secondary batteries are characterized by high energy density, and are widely used as power sources for portable electric devices such as mobile phones, portable music players, and notebook personal computers.
  • a normal lithium ion secondary battery is provided with a separator to prevent contact between the positive and negative electrodes.
  • a porous film made of polyethylene or polypropylene has been used as a battery separator.
  • a porous film made of polyethylene or polypropylene has low heat resistance, and when the porous film contracts and an internal short circuit occurs, local heat is generated inside the battery, and ignition or rupture occurs. I have a problem.
  • battery separators containing inorganic fine particles have been developed.
  • the battery separator containing the inorganic fine particles it is possible to suppress a short circuit due to an external impact.
  • a coating liquid containing inorganic fine particles is applied to the surface of the porous film.
  • the inorganic fine particles have a higher specific gravity than water and organic solvents, they tend to settle in the inorganic fine particle-containing slurry, and once settled, the inorganic fine particles may aggregate to cause a problem.
  • the dispersion state of the inorganic fine particles is not good, there is a problem that uneven coating occurs when applied to the porous film, and improvement of the stability of the inorganic fine particles in the coating liquid has been demanded.
  • a thickener is added to the coating liquid.
  • a thickener for example, a thickener such as xanthan gum is used.
  • Patent Document 1 and 2 using a cellulose fiber as a thickener is examined.
  • Patent Document 1 discloses a battery separator coating solution containing cellulose fibers.
  • bacterial cellulose fibers or nanocellulose fibers prepared by dissociating crystalline cellulose are used as thickeners.
  • Patent Document 2 discloses a battery separator coating solution containing fine cellulose fibers having an I-type crystal form to which a carboxyl group is added.
  • the battery separator coating liquid may be required to have good coating properties in addition to having excellent fine particle dispersibility. If the coatability is good, the productivity of the battery separator can be increased. Therefore, an object of the present invention is to provide a battery separator coating solution having both excellent fine particle dispersibility and coating property.
  • the present inventors have found that, in a thickener for battery separator coating liquid containing fibrous cellulose having a fiber width of 1000 nm or less, It was found that by setting the thixotropic index value (TI value) of the adhesive within a predetermined range, a battery separator coating liquid having both excellent fine particle dispersibility and coating property can be obtained.
  • the present invention has the following configuration.
  • the suspension is obtained by diluting with ion-exchanged water so that the concentration of fibrous cellulose having a fiber width of 1000 nm or less contained in the thickener for battery separator coating liquid is 0.4% by mass;
  • the viscosity of the liquid was measured with a rheometer, the viscosity measured under the conditions of a measurement temperature of 23 ° C., a measurement time of 5 minutes, and a shear rate of 1 sec ⁇ 1 was ⁇ 1 , a measurement temperature of 23 ° C., a measurement time of 5 minutes, and a shear rate of 1000 sec ⁇ when the the eta 2 viscosity measured at 1 conditions, the value of eta 1 / eta 2 thixotropic index value of
  • a battery separator coating liquid comprising the thickener for battery separator coating liquid according to any one of [1] to [3], fine particles, and a dispersion medium.
  • a battery separator coating solution having both excellent fine particle dispersibility and coating property can be obtained.
  • FIG. 1 is a graph showing the relationship between the amount of dropped NaOH and electrical conductivity for a fiber material having a phosphate group.
  • FIG. 2 is a graph showing the relationship between the amount of dropped NaOH and electrical conductivity for a fiber material having a carboxyl group.
  • the present invention relates to a thickener for a battery separator coating solution, which contains fibrous cellulose having a fiber width of 1000 nm or less and has a thixotropic index value (TI value) calculated under the following condition a of 100 or more.
  • TI value thixotropic index value
  • the suspension is obtained by diluting with ion-exchanged water so that the concentration of fibrous cellulose having a fiber width of 1000 nm or less contained in the thickener for battery separator coating liquid is 0.4% by mass;
  • the viscosity of the liquid was measured with a rheometer, the viscosity measured under the conditions of a measurement temperature of 23 ° C., a measurement time of 5 minutes, and a shear rate of 1 sec ⁇ 1 was ⁇ 1 , a measurement temperature of 23 ° C., a measurement time of 5 minutes, and a shear rate of 1000 sec ⁇ when the the eta 2 viscosity measured at 1 conditions, the value of eta 1 / eta 2 thixotropic index value of the separator coating solution for a thickener for a battery and (TI value).
  • the battery separator coating liquid containing the thickener for the battery separator coating liquid has excellent fine particle dispersibility and coatability. Can do.
  • the applicability can be evaluated based on the presence or absence of coating unevenness in the coating layer.
  • the battery separator including the coating layer formed from the battery separator coating liquid containing the battery separator coating liquid thickener of the present invention is highly safe because it has a coating layer without coating unevenness. Furthermore, when the battery separator coating liquid containing the battery separator coating liquid thickener of the present invention is applied onto the substrate, the battery separator coating liquid bleeds out to the back of the substrate. Is suppressed.
  • the thickener in the battery separator coating solution may become an impurity after coating, it is preferable that the amount added is small.
  • the present invention is also characterized in that the addition amount can be reduced by using the thickener for battery separator coating liquid.
  • the dispersibility of the fine particles can be enhanced even when the addition amount of the thickener for the battery separator coating liquid is small.
  • the coating property can also be improved by suppressing the addition amount of the thickener for battery separator coating liquids.
  • the microporous of the battery separator base material is block
  • the suppression of microporous clogging of the battery separator substrate and the prevention of occurrence of back-through are in a trade-off relationship, but in the present invention, by using the battery separator coating liquid thickener, Both suppression of microporous blockage of the substrate and prevention of occurrence of back-through are achieved.
  • the dispersibility of fine particles in the battery separator coating solution is improved.
  • the ease of application of the battery separator coating liquid can be enhanced. This is because the thickening effect of the battery separator coating liquid thickener is weakened to some extent by applying a shear (shearing force) during coating. That is, the battery separator coating liquid containing the thickener for the battery separator coating liquid of the present invention has a high viscosity and high fine particle dispersibility during storage without application of shear (shearing force) before coating, but shares during coating. When (shearing force) is applied, the viscosity is lowered to some extent, so that the ease of coating is enhanced.
  • shear shear
  • the thixotropic index value is a value representing the ratio of the viscosity under each condition when the viscosity is measured under two conditions with different shear rates for a suspension having a predetermined concentration.
  • the shear rate is low, the viscosity of the suspension is high, and when the shear rate is high, the viscosity of the suspension is low. That is, the thixotropic index value (TI value) is a value obtained by dividing the viscosity when measured under a low shear rate by the viscosity when measured under a high shear rate.
  • the thixotropic index value (TI value) of the thickener for battery separator coating liquid can be calculated from the viscosity at each shear rate measured under the following conditions.
  • the suspension is obtained by diluting with ion-exchanged water so that the concentration of fibrous cellulose having a fiber width of 1000 nm or less contained in the thickener for battery separator coating liquid is 0.4 mass%.
  • the viscosity of this suspension was measured with a rheometer, and the viscosity measured under the conditions of a measurement temperature of 23 ° C., a measurement time of 5 minutes, and a shear rate of 1 sec ⁇ 1 was ⁇ 1 , a measurement temperature of 23 ° C.
  • the viscosity measured under the conditions of minute and shear rate of 1000 sec ⁇ 1 is defined as ⁇ 2 .
  • HAAKE company make and RheoStress6000 can be mentioned, for example, A cone plate (diameter 40mm, angle 1 degree) can be used as a measurement jig
  • the thixotropic index value (TI value) of the thickener for battery separator coating liquid of the present invention may be 100 or more, preferably 150 or more, more preferably 200 or more, and 300 or more. Is more preferable, and 350 or more is particularly preferable. Further, the thixotropic index value (TI value) of the thickener for battery separator coating liquid is preferably 10,000 or less.
  • the viscosity ( ⁇ 1 ) measured under the conditions of a temperature of 23 ° C., a measurement time of 5 minutes, and a shear rate of 1 sec ⁇ 1 is preferably 1000 mPa ⁇ s or more, more preferably 3000 mPa ⁇ s or more, and 4000 mPa ⁇ s. More preferably, it is the above.
  • the viscosity of the battery separator coating solution is preferably 100,000 mPa ⁇ s or less, more preferably 80000 mPa ⁇ s or less, and further preferably 60000 mPa ⁇ s or less.
  • the viscosity of the suspension diluted with ion-exchanged water was measured with a rheometer so that the concentration of fine fibrous cellulose contained in the thickener for battery separator coating liquid was 0.4% by mass.
  • the viscosity ( ⁇ 2 ) measured under the conditions of a measurement temperature of 23 ° C., a measurement time of 5 minutes, and a shear rate of 1000 sec ⁇ 1 is preferably 5 mPa ⁇ s or more, more preferably 10 mPa ⁇ s or more, and 20 mPa -More preferably, it is s or more.
  • the viscosity of the battery separator coating liquid is preferably 1000 mPa ⁇ s or less, more preferably 800 mPa ⁇ s or less, and even more preferably 600 mPa ⁇ s or less.
  • the battery separator coating liquid thickener of the present invention contains fibrous cellulose having a fiber width of 1000 nm or less.
  • fibrous cellulose having a fiber width of 1000 nm or less is also referred to as fine fibrous cellulose.
  • the thickener for battery separator coating liquid preferably contains 60% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass or more of such fine fibrous cellulose with respect to the total solid mass. More preferably, it is more preferably 90% by mass or more.
  • the thickener for the battery separator coating liquid may be composed of the above-mentioned fine fibrous cellulose, but the thickener for the battery separator coating liquid contains water in addition to the above fine fibrous cellulose. And other solvents, water-soluble polymers and the like may be contained.
  • Examples of the form of the thickener for battery separator coating liquid of the present invention include powder, gel, slurry, solution, and sheet.
  • the average degree of polymerization of the fine fibrous cellulose contained in the battery separator coating liquid thickener is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more. Further, the average degree of polymerization of the fine fibrous cellulose is preferably 2000 or less, more preferably 1500 or less, further preferably 1200 or less, still more preferably 1000 or less, and 750 or less. It is particularly preferred.
  • the average degree of polymerization of the fine fibrous cellulose may be less than 400, but the average degree of polymerization of the fine fibrous cellulose is preferably 400 or more from the viewpoint of preventing the see-through.
  • the average degree of polymerization of the fine fibrous cellulose contained in the battery separator coating liquid thickener is calculated with reference to the following paper. TAPPI International Standard; ISO / FDIS 5351, 2009. Smith, D. K .; Bampton, R. F .; Alexander, W. J. Ind. Eng. Chem., Process Des. Dev. 1963, 2, 57-62.
  • the degree of polymerization is calculated from the mass of the absolutely dry fine fibrous cellulose used for the measurement, the solvent dropping time, and the dropping time of the fine fibrous cellulose solution using the following equation. In addition, when the following average degree of polymerization is measured twice or more, it is an average value of each time.
  • the thickener for battery separator coating liquids when components other than fine fibrous cellulose are contained in the thickener for battery separator coating liquids, after the fine fibrous cellulose is isolated, the average degree of polymerization of the fine fibrous cellulose is calculated. In this case, first, the battery separator coating liquid thickener is diluted and dried, and then observed with a transmission electron microscope to confirm the presence of fine fibrous cellulose. Subsequently, the type I crystal
  • the fine fibrous cellulose is isolated according to the following procedure. First, 20 ⁇ 5 g of thickener for battery separator coating liquid is weighed into a 50 ml capacity aluminum cup. Similarly, a plurality of aluminum cups prepared by measuring the thickener for battery separator coating liquid are prepared. It heats at 105 degreeC with a ventilation constant temperature dryer for 16 hours, and dries the thickener for battery separator coating liquids. A 0.5 mol / L copper ethylenediamine solution is added to 1 g of the thickening agent for battery separator coating liquid thus dried so as to have a ratio of 200 ml, and stirred to dissolve the fine fibrous cellulose.
  • the obtained solution is filtered to remove the residue, and then dropped into water to obtain regenerated cellulose.
  • This regenerated cellulose is obtained by dissolving fine fibrous cellulose in a copper ethylenediamine solution and regenerating it in water. The obtained regenerated cellulose is filtered off, washed thoroughly with water and dried.
  • the dry weight of the obtained regenerated cellulose is measured. From this weight and the weight of the thickener for battery separator coating solution used to obtain this weight, the content of fine fibrous cellulose contained in the thickener for battery separator coating solution is determined.
  • ⁇ Fine fibrous cellulose> Although it does not specifically limit as a fibrous cellulose raw material for obtaining a fine fibrous cellulose, It is preferable to use a pulp from the point of being easy to acquire and cheap.
  • the pulp include wood pulp, non-wood pulp, and deinked pulp.
  • wood pulp include hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), oxygen bleached craft Chemical pulps such as pulp (OKP) are listed.
  • semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-ground wood pulp (CGP), mechanical pulps such as ground wood pulp (GP), thermomechanical pulp (TMP, BCTMP) and the like can be mentioned, but are not particularly limited.
  • Non-wood pulp includes cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw and bagasse, cellulose isolated from sea squirts and seaweed, chitin, chitosan, etc., but is not particularly limited.
  • the deinking pulp includes deinking pulp made from waste paper, but is not particularly limited. The pulp of this embodiment may be used alone or in combination of two or more.
  • wood pulp containing cellulose and deinked pulp are preferable in terms of availability.
  • chemical pulp has a large cellulose ratio, so the yield of fine fibrous cellulose during fiber refinement (defibration) is high, and the degradation of cellulose in the pulp is small, and the fineness of long fibers with a large axial ratio is high. It is preferable at the point from which fibrous cellulose is obtained.
  • kraft pulp and sulfite pulp are most preferably selected. When long fiber fine fibrous cellulose having a large axial ratio is used, high viscosity tends to be obtained.
  • the average fiber width of the fine fibrous cellulose is 1000 nm or less as observed with an electron microscope.
  • the average fiber width is preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, more preferably 2 nm or more and 50 nm or less, and further preferably 2 nm or more and 10 nm or less, but is not particularly limited.
  • the average fiber width of the fine fibrous cellulose is less than 2 nm, the physical properties (strength, rigidity, dimensional stability) as the fine fibrous cellulose tend to be difficult to be expressed because the cellulose molecules are dissolved in water. .
  • the fine fibrous cellulose is monofilamentous cellulose having a fiber width of 1000 nm or less, for example.
  • the measurement of the average fiber width of the fine fibrous cellulose by electron microscope observation is performed as follows.
  • An aqueous suspension of fine fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less is prepared, and the suspension is cast on a carbon film-coated grid subjected to a hydrophilic treatment to prepare a sample for TEM observation. To do.
  • an SEM image of the surface cast on glass may be observed.
  • Observation with an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 times, or 50000 times depending on the width of the constituent fibers.
  • the sample, observation conditions, and magnification are adjusted to satisfy the following conditions.
  • One straight line X is drawn at an arbitrary location in the observation image, and 20 or more fibers intersect the straight line X.
  • a straight line Y perpendicular to the straight line is drawn in the same image, and 20 or more fibers intersect the straight line Y.
  • the average fiber width (sometimes simply referred to as “fiber width”) of fine fibrous cellulose is an average value of the fiber widths read in this way.
  • the fiber length of the fine fibrous cellulose is not particularly limited, but is preferably 0.1 ⁇ m or more and 1000 ⁇ m or less, more preferably 0.1 ⁇ m or more and 800 ⁇ m or less, and particularly preferably 0.1 ⁇ m or more and 600 ⁇ m or less.
  • the fiber length of the fine fibrous cellulose can be determined by image analysis using TEM, SEM, or AFM.
  • the fine fibrous cellulose preferably has an I-type crystal structure.
  • the proportion of the I-type crystal structure in the fine fibrous cellulose is preferably 30% or more, more preferably 50% or more, and further preferably 70% or more. In this case, further superior performance can be expected in terms of heat resistance and low linear thermal expansion coefficient.
  • the degree of crystallinity is obtained by measuring an X-ray diffraction profile and determining the crystallinity by a conventional method (Seagal et al., Textile Research Journal, 29, 786, 1959).
  • the fine fibrous cellulose is preferably one having a substituent, and the substituent is preferably an anionic group.
  • the anionic group include a phosphate group or a substituent derived from a phosphate group (sometimes simply referred to as a phosphate group), a carboxyl group or a substituent derived from a carboxyl group (sometimes simply referred to as a carboxyl group),
  • it is preferably at least one selected from a sulfone group or a substituent derived from a sulfone group (sometimes simply referred to as a sulfone group), and at least one selected from a phosphate group and a carboxyl group Is more preferable, and a phosphate group is particularly preferable. That is, the fine fibrous cellulose used in the present invention is preferably phosphorylated cellulose.
  • the fine fibrous cellulose is preferably one having a phosphate group or a substituent derived from a phosphate group.
  • the phosphoric acid group is a divalent functional group equivalent to the phosphoric acid obtained by removing the hydroxyl group. Specifically, it is a group represented by —PO 3 H 2 .
  • Substituents derived from phosphoric acid groups include substituents such as groups obtained by polycondensation of phosphoric acid groups, salts of phosphoric acid groups, and phosphoric acid ester groups. It may be a group.
  • the phosphate group or the substituent derived from the phosphate group may be a substituent represented by the following formula (1).
  • R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched hydrocarbon group, respectively.
  • Examples of the saturated-linear hydrocarbon group include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, or an n-butyl group.
  • Examples of the saturated-branched hydrocarbon group include i-propyl group and t-butyl group, but are not particularly limited.
  • Examples of the saturated-cyclic hydrocarbon group include a cyclopentyl group and a cyclohexyl group, but are not particularly limited.
  • Examples of the unsaturated-linear hydrocarbon group include a vinyl group and an allyl group, but are not particularly limited.
  • Examples of the unsaturated-branched hydrocarbon group include i-propenyl group and 3-butenyl group, but are not particularly limited.
  • Examples of the unsaturated-cyclic hydrocarbon group include a cyclopentenyl group and a cyclohexenyl group, but are not particularly limited.
  • Examples of the aromatic group include, but are not limited to, a phenyl group or a naphthyl group.
  • the derivative group in R is a functional group in which at least one of functional groups such as a carboxy group, a hydroxy group, or an amino group is added or substituted to the main chain or side chain of various hydrocarbon groups.
  • the number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, and more preferably 10 or less.
  • ⁇ b + is a monovalent or higher cation composed of an organic substance or an inorganic substance.
  • the monovalent or higher cation made of an organic substance include aliphatic ammonium or aromatic ammonium.
  • examples of the monovalent or higher cation made of an inorganic substance include ions of alkali metals such as sodium, potassium, or lithium, Examples include, but are not particularly limited to, a cation of a divalent metal such as calcium or magnesium, or a hydrogen ion. These can be applied alone or in combination of two or more.
  • the monovalent or higher cation composed of an organic substance or an inorganic substance is preferably a sodium ion or potassium ion which is not easily yellowed when heated to a fiber raw material containing ⁇ b + and is industrially easy to use, but is not particularly limited. .
  • the fiber raw material containing cellulose is reacted with at least one selected from a compound having a phosphate group and a salt thereof (hereinafter referred to as “phosphorylation reagent” or “compound A”).
  • a phosphorylating reagent may be mixed in a powder or aqueous solution with a dry or wet fiber raw material.
  • a phosphorylating reagent powder or an aqueous solution may be added to the fiber raw material slurry.
  • the phosphoric acid group introduction step can be performed by reacting a fiber raw material containing cellulose with at least one selected from a phosphoric acid group-containing compound and a salt thereof (phosphorylation reagent or compound A). This reaction may be carried out in the presence of at least one selected from urea and derivatives thereof (hereinafter referred to as “compound B”).
  • An example of a method for causing compound A to act on the fiber raw material in the presence of compound B is a method of mixing powder or an aqueous solution of compound A and compound B with a dry or wet fiber raw material.
  • Another example is a method in which powders and aqueous solutions of Compound A and Compound B are added to the fiber raw material slurry.
  • a method of adding an aqueous solution of Compound A and Compound B to a dry fiber material, or a powder or an aqueous solution of Compound A and Compound B to a wet fiber material is preferred.
  • the compound A and the compound B may be added simultaneously, or may be added separately.
  • the form of the fiber raw material is preferably cotton or thin sheet, but is not particularly limited.
  • Compound A used in this embodiment is at least one selected from a compound having a phosphate group and a salt thereof.
  • the compound having a phosphate group include, but are not limited to, phosphoric acid, lithium salt of phosphoric acid, sodium salt of phosphoric acid, potassium salt of phosphoric acid, ammonium salt of phosphoric acid, and the like.
  • the lithium salt of phosphoric acid include lithium dihydrogen phosphate, dilithium hydrogen phosphate, trilithium phosphate, lithium pyrophosphate, and lithium polyphosphate.
  • Examples of the sodium salt of phosphoric acid include sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, and sodium polyphosphate.
  • Examples of the potassium salt of phosphoric acid include potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, and potassium polyphosphate.
  • Examples of the ammonium salt of phosphoric acid include ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium polyphosphate.
  • phosphoric acid and phosphoric acid are introduced efficiently from the viewpoint that the introduction efficiency of phosphate groups is high, the fibrillation efficiency is easily improved in the fibrillation process described later, the cost is low, and the industrial application is easy.
  • Sodium salt, potassium salt of phosphoric acid, and ammonium salt of phosphoric acid are preferable.
  • Sodium dihydrogen phosphate or disodium hydrogen phosphate is more preferable.
  • the compound A is preferably used as an aqueous solution because the uniformity of the reaction is increased and the efficiency of introducing a phosphate group is increased.
  • the pH of the aqueous solution of Compound A is not particularly limited, but is preferably 7 or less because the efficiency of introduction of phosphate groups is increased, and more preferably pH 3 or more and pH 7 or less from the viewpoint of suppressing the hydrolysis of pulp fibers.
  • the pH of the aqueous solution of Compound A may be adjusted by, for example, using a phosphoric acid group-containing compound that exhibits acidity and an alkalinity, and changing the amount ratio thereof. You may adjust pH of the aqueous solution of the compound A by adding an inorganic alkali or an organic alkali to the thing which shows acidity among the compounds which have a phosphoric acid group.
  • the amount of compound A added to the fiber raw material is not particularly limited, but when the amount of compound A added is converted to phosphorus atomic weight, the amount of phosphorus atom added to the fiber raw material (absolute dry mass) is 0.5 mass% to 100 mass%. Or less, more preferably 1% by mass or more and 50% by mass or less, and most preferably 2% by mass or more and 30% by mass or less. If the amount of phosphorus atoms added to the fiber raw material is within the above range, the yield of fine fibrous cellulose can be further improved. By making the amount of phosphorus atoms added to the fiber raw material 100% by mass or less, it is possible to balance the effect of improving the yield and the cost. On the other hand, a yield can be raised by making the addition amount of the phosphorus atom with respect to a cellulose fiber more than the said lower limit.
  • Compound B used in this embodiment includes urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like.
  • Compound B is preferably used as an aqueous solution like Compound A. Moreover, since the uniformity of reaction increases, it is preferable to use the aqueous solution in which both compound A and compound B are dissolved.
  • the amount of Compound B added to the fiber raw material is preferably 1% by mass or more and 500% by mass or less, more preferably 10% by mass or more and 400% by mass or less, and 100% by mass or more and 350% by mass or less. More preferably, it is more preferably 150% by mass or more and 300% by mass or less.
  • amides or amines may be included in the reaction system.
  • amides include formamide, dimethylformamide, acetamide, dimethylacetamide and the like.
  • amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine, and the like. Among these, triethylamine is known to work as a good reaction catalyst.
  • the heat treatment temperature it is preferable to select a temperature at which a phosphate group can be efficiently introduced while suppressing thermal decomposition and hydrolysis reaction of the fiber. Specifically, it is preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower. Moreover, you may use a vacuum dryer, an infrared heating apparatus, and a microwave heating apparatus for a heating.
  • the concentration of the compound A in the fiber raw material may be uneven, and the introduction of phosphate groups on the fiber surface may not proceed uniformly.
  • a very thin sheet-like fiber material is used, or the fiber material and Compound A are kneaded or stirred with a kneader or the like and dried by heating or reduced pressure. The method should be taken.
  • the heating device used for the heat treatment is preferably a device that can always discharge the moisture retained by the slurry and the moisture generated by the addition reaction of the fibers such as phosphate groups to the hydroxyl group of the fiber, such as a blower oven. Etc. are preferred. If water in the system is always discharged, the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the esterification, can be suppressed, and the acid hydrolysis of the sugar chain in the fiber can also be suppressed. A fine fiber having a high axial ratio can be obtained.
  • the heat treatment time is also affected by the heating temperature, but it is preferably 1 second or more and 300 minutes or less, preferably 1 second or more and 1000 seconds or less after moisture is substantially removed from the fiber raw material slurry. Preferably, it is 10 seconds or more and 800 seconds or less.
  • the amount of phosphate groups introduced can be within a preferred range by setting the heating temperature and the heating time to appropriate ranges.
  • the phosphate group introduction step may be performed at least once, but may be repeated a plurality of times. In this case, more phosphoric acid groups are introduced, which is preferable. In the present invention, for example, it is also a preferred embodiment to perform the phosphate group introduction step twice.
  • the amount of phosphate group introduced is preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.50 mmol / g or more per 1 g (mass) of fine fibrous cellulose. More preferably, it is particularly preferably 1.00 mmol / g or more.
  • the amount of phosphate groups introduced is preferably 3.65 mmol / g or less, more preferably 3.50 mmol / g or less, and 3.00 mmol / g or less per 1 g (mass) of fine fibrous cellulose. More preferably.
  • the introduction amount of the phosphoric acid group within the above range, the fiber raw material can be easily refined, and the stability of the fine fibrous cellulose can be enhanced. Moreover, by setting the introduction amount of phosphate groups within the above range, good characteristics can be exhibited as a thickener for battery separator coating liquid.
  • content of the phosphoric acid group which a fine fibrous cellulose has is equal to the strongly acidic group amount of the phosphoric acid group which a fine fibrous cellulose has so that it may mention later.
  • the amount of phosphate group introduced into the fiber material can be measured by a conductivity titration method. Specifically, by performing the defibration process step, after treating the resulting fine fibrous cellulose-containing slurry with an ion exchange resin, by determining the change in electrical conductivity while adding an aqueous sodium hydroxide solution, The amount introduced can be measured.
  • first region the electrical conductivity rapidly decreases
  • second region the conductivity starts to increase slightly
  • third region the conductivity increment increases
  • the boundary point between the second region and the third region is defined as a point at which the amount of change in conductivity twice, that is, the increase (inclination) in conductivity is maximized. That is, three areas appear.
  • the amount of alkali required in the first region is equal to the amount of strongly acidic groups in the slurry used for titration
  • the amount of alkali required in the second region is the amount of weakly acidic groups in the slurry used for titration. Will be equal.
  • the amount of alkali required in the second region is reduced compared to the amount of alkali required in the first region.
  • the amount of strongly acidic groups coincides with the amount of phosphorus atoms regardless of the presence or absence of condensation, so that the amount of phosphate groups introduced (or the amount of phosphate groups) or the amount of substituent introduced (or the amount of substituents) is simply When said, it represents the amount of strongly acidic group. That is, the alkali amount (mmol) required in the first region of the curve shown in FIG. 1 is divided by the solid content (g) in the titration target slurry to obtain the substituent introduction amount (mmol / g).
  • the carboxyl group can be introduced into the fine fibrous cellulose through a carboxyl group introduction step.
  • the fiber raw material is treated with an oxidation treatment such as a TEMPO oxidation treatment or a compound having a group derived from a carboxylic acid, a derivative thereof, or an acid anhydride or a derivative thereof, whereby a carboxyl group is added to the fine fibrous cellulose.
  • an oxidation treatment such as a TEMPO oxidation treatment or a compound having a group derived from a carboxylic acid, a derivative thereof, or an acid anhydride or a derivative thereof, whereby a carboxyl group is added to the fine fibrous cellulose.
  • the compound having a carboxyl group is not particularly limited, and examples thereof include dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid and itaconic acid, and tricarboxylic acid compounds such as citric acid and aconitic acid. .
  • the acid anhydride of the compound having a carboxyl group is not particularly limited, but examples thereof include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. It is done.
  • the derivative of the compound having a carboxyl group is not particularly limited, and examples thereof include an acid anhydride imidized compound having a carboxyl group and an acid anhydride derivative of a compound having a carboxyl group. Although it does not specifically limit as an acid anhydride imidation thing of a compound which has a carboxyl group, Imidation thing of dicarboxylic acid compounds, such as maleimide, succinic acid imide, and phthalic acid imide, is mentioned.
  • the acid anhydride derivative of the compound having a carboxyl group is not particularly limited.
  • at least some of the hydrogen atoms of the acid anhydride of the compound having a carboxyl group such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride, etc. are substituted (for example, alkyl group, phenyl group, etc. ) Are substituted.
  • the amount of carboxyl groups introduced is preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.50 mmol / g or more per 1 g (mass) of fine fibrous cellulose. Is more preferable, and 0.90 mmol / g or more is particularly preferable.
  • the amount of carboxyl group introduced is preferably 3.65 mmol / g or less, more preferably 3.50 mmol / g or less, and further preferably 3.00 mmol / g or less.
  • the amount of carboxyl group introduced can be measured by a conductivity titration method.
  • the introduction amount is measured by obtaining a change in conductivity while adding an aqueous sodium hydroxide solution to the obtained fine fibrous cellulose-containing slurry.
  • the curve shown in FIG. 2 is given when alkali is added. This curve is divided into a first region until the conductivity increment (slope) becomes substantially constant after the electrical conductivity decreases, and then a second region where the conductivity increment (slope) increases. Note that the boundary point between the first region and the second region is defined as the point at which the amount of change in conductivity twice, that is, the increase (inclination) in conductivity is maximized.
  • the alkali amount (mmol) required in the first region of the curve shown in FIG. 2 is divided by the solid content (g) in the fine fibrous cellulose-containing slurry to be titrated, and the amount of carboxyl group introduced (mmol / g).
  • an alkali treatment may be performed between an ionic substituent introduction step such as a phosphate group introduction step or a carboxyl group introduction step and a defibration treatment step described later.
  • an ionic substituent introduction step such as a phosphate group introduction step or a carboxyl group introduction step
  • an alkali treatment For example, the method of immersing an ionic substituent introduction
  • the alkali compound contained in the alkali solution is not particularly limited, but may be an inorganic alkali compound or an organic alkali compound.
  • the solvent in the alkaline solution may be either water or an organic solvent.
  • the solvent is preferably a polar solvent (polar organic solvent such as water or alcohol), and more preferably an aqueous solvent containing at least water.
  • a polar solvent polar organic solvent such as water or alcohol
  • an aqueous solvent containing at least water preferably an aqueous solvent containing at least water.
  • a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution is particularly preferred because of its high versatility.
  • the temperature of the alkali solution in an alkali treatment process is not specifically limited, 5 to 80 degreeC is preferable and 10 to 60 degreeC is more preferable.
  • the immersion time in the alkaline solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes or longer and 30 minutes or shorter, and more preferably 10 minutes or longer and 20 minutes or shorter.
  • the usage-amount of the alkali solution in an alkali treatment is not specifically limited, It is preferable that it is 100 mass% or more and 100,000 mass% or less with respect to the absolute dry mass of an ionic substituent introduction
  • the ionic substituent-introduced fiber may be washed with water or an organic solvent before the alkali treatment step.
  • the alkali treatment in order to improve the handleability, it is preferable to wash the alkali-treated ionic substituent-introduced fiber with water or an organic solvent before the defibrating treatment step.
  • ⁇ Acid treatment> When manufacturing a fine fibrous cellulose, you may perform an acid treatment between an ionic substituent introduction
  • the acid treatment method is not particularly limited, and examples thereof include a method of immersing the ionic substituent-introducing fiber in an acid solution containing an acid.
  • concentration of the acidic liquid to be used is not specifically limited, 10 mass% or less is preferable, More preferably, it is 5 mass% or less.
  • the pH of the acidic solution to be used is not particularly limited, but is preferably 0 to 4, more preferably 1 to 3.
  • an inorganic acid, a sulfonic acid, a carboxylic acid, or the like can be used.
  • Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, phosphoric acid, boric acid and the like.
  • Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, and the like.
  • Examples of the carboxylic acid include formic acid, acetic acid, citric acid, gluconic acid, lactic acid, oxalic acid, and tartaric acid. Of these, hydrochloric acid is preferably used as the acid.
  • the temperature of the acid solution in an acid treatment process is not specifically limited, 5 to 100 degreeC is preferable and 20 to 90 degreeC is more preferable.
  • the immersion time in the acid solution in an acid treatment process is not specifically limited, 5 minutes or more and 120 minutes or less are preferable, and 10 minutes or more and 60 minutes or less are more preferable.
  • the usage-amount of the acid solution in an acid treatment is not specifically limited, It is preferable that it is 100 mass% or more and 100,000 mass% or less with respect to the absolute dry mass of an ionic substituent introduction
  • the ionic substituent-introduced fiber is defibrated in the defibrating process.
  • the fiber is usually defibrated using a defibrating apparatus to obtain a fine fibrous cellulose-containing slurry, but the processing apparatus and the processing method are not particularly limited.
  • a defibrating apparatus a high-speed defibrator, a grinder (stone mill type pulverizer), a high-pressure homogenizer, an ultra-high pressure homogenizer, a high-pressure collision type pulverizer, a ball mill, a bead mill, or the like can be used.
  • a device for wet grinding such as a disk type refiner, a conical refiner, a twin-screw kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, or a beater should be used. You can also.
  • the defibrating apparatus is not limited to the above.
  • Preferable defibrating treatment methods include a high-speed defibrator, a high-pressure homogenizer, and an ultra-high pressure homogenizer that are less affected by the grinding media and less concerned about contamination.
  • polar organic solvent in addition to water, a polar organic solvent can be used.
  • polar organic solvents include alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and the like, but are not particularly limited.
  • alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butyl alcohol.
  • ketones include acetone and methyl ethyl ketone (MEK).
  • ethers include diethyl ether and tetrahydrofuran (THF).
  • THF tetrahydrofuran
  • the dispersion medium may be one type or two or more types. Further, the dispersion medium may contain a solid content other than the fiber raw material, such as urea having hydrogen bonding property.
  • the fibrillation treatment may be performed after the fine fibrous cellulose is concentrated and dried.
  • the concentration and drying methods are not particularly limited, and examples thereof include a method of adding a concentrating agent to a slurry containing fine fibrous cellulose, a generally used dehydrator, a press, and a method using a dryer.
  • a well-known method for example, the method described in WO2014 / 024876, WO2012 / 107642, and WO2013 / 121086 can be used.
  • the concentrated fine fibrous cellulose may be formed into a sheet. The sheet can be pulverized to perform a defibrating process.
  • the equipment used for pulverization of fine fibrous cellulose includes high-speed defibrator, grinder (stone mill type pulverizer), high-pressure homogenizer, ultra-high pressure homogenizer, high-pressure collision type pulverizer, ball mill, bead mill, disk type refiner, conical
  • An apparatus for wet pulverization such as a refiner, a twin-screw kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, a beater, and the like can be used, but is not particularly limited.
  • the treatment conditions are not particularly limited as long as a preferable degree of polymerization is obtained.
  • the thickener for the battery separator coating liquid is used. It is possible to control the thixotropic index value (TI value) in a desired range.
  • the ionic substituent to be introduced is preferably a phosphoric acid group or a carboxyl group, and when the ionic substituent is a carboxyl group, the reaction is preferably performed under conditions of pH 6 or more and 8 or less. It is also possible to adjust the pressure conditions and the number of treatments in the defibrating process, and to select the type of manufacturing apparatus.
  • the average degree of polymerization of the fine fibrous cellulose is controlled within a preferable range by setting the number of processes to 1 to 8 times. Also good.
  • the present invention also relates to a battery separator coating liquid containing the above-described thickener for battery separator coating liquid, fine particles, and a dispersion medium. That is, the battery separator coating solution of the present invention contains fibrous cellulose having a fiber width of 1000 nm or less, and has a thixotropic index value (TI value) calculated under the above condition a of 100 or more. Contains a thickener.
  • the fibrous cellulose having a fiber width of 1000 nm or less is the above-described fine fibrous cellulose, and the fine fibrous cellulose is preferably phosphorylated cellulose having a fiber width of 1000 nm or less.
  • the average degree of polymerization of the fine fibrous cellulose is preferably 100 or more, more preferably 150 or more, and further preferably 200 or more. Further, the average degree of polymerization of the fine fibrous cellulose is preferably 2000 or less, more preferably 1500 or less, further preferably 1200 or less, still more preferably 1000 or less, and 750 or less. It is particularly preferred.
  • the average degree of polymerization of the fine fibrous cellulose may be less than 400, but the average degree of polymerization of the fine fibrous cellulose is preferably 400 or more from the viewpoint of preventing the see-through.
  • the measurement is performed after the fine fibrous cellulose is isolated from the battery separator coating liquid by the following procedure.
  • the battery separator coating solution is diluted and dried, and then observed with a transmission electron microscope to confirm the presence of fine fibrous cellulose.
  • the type I crystal of cellulose is detected using solid-state NMR.
  • the fine fibrous cellulose is isolated according to the following procedure. First, 20 ⁇ 5 g of battery separator coating solution is weighed into a 50 ml capacity aluminum cup. Similarly, a plurality of aluminum cups prepared by weighing battery separator coating liquid are prepared. It heats at 105 degreeC with a ventilation constant temperature dryer for 16 hours, and dries the separator coating liquid for batteries. A 0.5 mol / L copper ethylenediamine solution is added to 1 g of the dried battery separator coating solution so as to have a ratio of 100 ml and stirred to dissolve the fine fibrous cellulose. The obtained solution is filtered to remove the residue, and then dropped into water to obtain regenerated cellulose. This regenerated cellulose is obtained by dissolving fine fibrous cellulose in a copper ethylenediamine solution and regenerating it in water. The obtained regenerated cellulose is filtered off, sufficiently washed with water, and dried.
  • the dry weight of the obtained regenerated cellulose is measured.
  • the content of fine fibrous cellulose contained in the battery separator coating solution is determined from this weight and the weight of the battery separator coating solution used to obtain this weight.
  • the content of fine fibrous cellulose is preferably 0.1 parts by mass or more and 2.0 parts by mass or less with respect to 100 parts by mass of the dispersion medium of the battery separator coating liquid.
  • the content of fine fibrous cellulose is more preferably 0.2 parts by mass or more, and further preferably 0.3 parts by mass or more. Further, the content of fine fibrous cellulose is more preferably 1.3 parts by mass or less, and further preferably 1.1 parts by mass or less, with respect to 100 parts by mass of the dispersion medium of the battery separator coating liquid. preferable.
  • the dispersibility of fine particles and the coating property are compatible.
  • the coating layer formed from the battery separator coating liquid of the present invention has suppressed occurrence of coating unevenness. Furthermore, in the present invention, the penetration of the battery separator coating liquid that oozes out to the back of the substrate is suppressed.
  • Examples of the fine particles contained in the battery separator coating liquid include organic fine particles and inorganic fine particles. Among these, the fine particles are preferably inorganic fine particles.
  • Examples of the resin constituting the organic fine particles include aromatic vinyl compounds such as styrene, ⁇ -methylstyrene, p-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and the like.
  • the inorganic fine particles include iron oxide, Al 2 O 3 (alumina), SiO 2 (silica), TiO 2 , BaTiO 3 , ZrO 2 , Li 3 PO 4 (trilithium phosphate), SrTiO 3 , SnO 2 , CeO 2, MgO, NiO, CaO , ZnO, Y 2 O 3, Pb (Zr, Ti) O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), Pb (Mg 1 / 3 Nb 2/3 ) O 3 —PbTiO 3 (PMN-PT), HfO 2 , Li 3 PO 4 , Li x Ti y (PO 4 ) 3 (0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 3), Li x Al y Ti z (PO 4 ) 3 (0 ⁇ x ⁇ 2,0 ⁇ y ⁇ 1,0 ⁇ z ⁇ 3), (LiAlTiP) x O y (0 ⁇
  • covalently bonded crystal fine particles such as silicon and diamond; clay fine particles such as talc and montmorillonite; substances derived from mineral resources such as boehmite (AlOOH), zeolite, apatite, kaolin, mullite, spinel, olivine, sericite, bentonite or the like
  • carbonaceous fine particles such as carbon black and graphite
  • at least one kind of fine particles selected from alumina, silica and boehmite is preferable, and silica or boehmite is particularly preferable.
  • the surface of the fine particles may be coated with a material having electrical insulating properties (for example, a material constituting the insulating fine particles, etc.) to obtain fine particles having electrical insulating properties.
  • the form of the fine particles may be any form such as a spherical shape, a polyhedral shape, or a plate shape.
  • the primary average particle diameter of the fine particles is preferably 0.01 ⁇ m or more, and preferably 5 ⁇ m or less.
  • the value obtained by calculating the primary average particle diameter assuming that the fine particles are spherical with the same volume is within the above range.
  • the content of the fine particles is preferably 5% by mass or more, and more preferably 10% by mass or more with respect to the total mass of the battery separator coating liquid.
  • the content of the fine particles is preferably 90% by mass or less, more preferably 80% by mass or less, and further preferably 70% by mass or less.
  • the heat resistance of the battery separator base material mentioned later can be improved more effectively.
  • the content of the fine particles is, for example, 10% by mass or less, the collision probability between the fine particles decreases, and a tendency to settle more easily is observed.
  • the battery separator coating liquid of the present invention contains fine fibrous cellulose having a predetermined condition, sedimentation of fine particles can be suppressed even when the content of fine particles is small.
  • the battery separator coating liquid contains a dispersion medium.
  • the dispersion medium include water, organic solvents, and mixtures thereof. Of these, the dispersion medium is preferably water.
  • the organic solvent include toluene, tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, isopropyl alcohol and the like.
  • the dispersion medium refers to the remaining part of the battery separator coating liquid excluding the solid content remaining upon drying when the coating layer is formed.
  • the content of the dispersion medium is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more with respect to the total mass of the battery separator coating liquid. . Further, the content of the dispersion medium is preferably 90% by mass or less, and more preferably 80% by mass or less.
  • the battery separator coating liquid may further contain a binder component in addition to the above components.
  • a binder component include, for example, ethylene-vinyl acetate copolymer; (meth) acrylic acid copolymer such as ethylene-ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer; fluorine-based rubber; styrene -Butadiene rubber (SBR); polyvinyl alcohol (PVA); polyvinyl butyral (PVB); polyvinyl pyrrolidone (PVP); poly N-vinylacetamide; crosslinked acrylic resin; polyurethane; These binder components may be used individually by 1 type, and may use 2 or more types together.
  • adhesion to the battery separator substrate described later can be enhanced.
  • the content of the binder component is preferably 15% by mass or less based on the total mass of the fine particles in the battery separator
  • hydrophilic polymers examples include polyethylene glycol, cellulose derivatives (hydroxyethylcellulose, carboxyethylcellulose, carboxymethylcellulose, etc.), casein, dextrin, starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol, etc.), Examples thereof include polyethylene oxide, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylates, polyacrylamide, alkyl acrylate copolymer, urethane copolymer, and the like.
  • organic ions include tetraalkylammonium ions and tetraalkylphosphonium ions.
  • tetraalkylammonium ions include tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrahexylammonium ion, tetraheptylammonium ion, tributylmethylammonium ion, and lauryltrimethyl.
  • Examples include ammonium ion, cetyltrimethylammonium ion, stearyltrimethylammonium ion, octyldimethylethylammonium ion, lauryldimethylethylammonium ion, didecyldimethylammonium ion, lauryldimethylbenzylammonium ion, and tributylbenzylammonium ion.
  • tetraalkylphosphonium ions examples include tetramethylphosphonium ions, tetraethylphosphonium ions, tetrapropylphosphonium ions, tetrabutylphosphonium ions, and lauryltrimethylphosphonium ions.
  • examples of the tetrapropylonium ion and the tetrabutylonium ion include tetra n-propylonium ion and tetra n-butylonium ion, respectively.
  • the content of the hydrophilic polymer or organic ion is preferably 20% by mass or less based on the total mass of the fine particles in the battery separator coating liquid.
  • the present invention also relates to a battery separator having a substrate and a coating layer.
  • a coating layer contains the thickener for battery separator coating liquids mentioned above, and microparticles
  • a coating layer is a layer formed from the battery separator coating liquid described above.
  • the battery separator is not limited as long as it has a coating layer on at least one surface of the substrate, and may have a coating layer on both surfaces of the substrate. It is preferable that it has.
  • a part of the battery separator coating liquid forming the coating layer may penetrate into the microporous interior of the substrate. Such a state can also be said to be a state in which a part of the battery separator coating solution is infiltrated into the surface layer region of the substrate.
  • the battery separator is formed by coating the above-described battery separator coating liquid on a substrate.
  • the coating layer formed by coating contains a thickener for battery separator coating liquid and contains the above-described fine fibrous cellulose.
  • the fine fibrous cellulose is preferably phosphorylated cellulose.
  • the average degree of polymerization of the fine fibrous cellulose is preferably 100 or more, more preferably 150 or more, and further preferably 200 or more. Further, the average degree of polymerization of the fine fibrous cellulose is preferably 2000 or less, more preferably 1500 or less, further preferably 1200 or less, still more preferably 1000 or less, and 750 or less. It is particularly preferred.
  • the average degree of polymerization of the fine fibrous cellulose may be less than 400, but the average degree of polymerization of the fine fibrous cellulose is preferably 400 or more from the viewpoint of preventing the see-through.
  • the measurement is performed after the fine fibrous cellulose is isolated from the battery separator by the following procedure.
  • the surface of the battery separator is observed with a transmission electron microscope to confirm the presence of fine fibrous cellulose.
  • the type I crystal of cellulose is detected using solid-state NMR.
  • the fine fibrous cellulose is isolated according to the following procedure. First, the battery separator is cut to about 1 cm square, and then pulverized to about 1 mm square using a cutter mill. Next, a 0.5 mol / L copper ethylenediamine solution is added to 1 g of the pulverized product of the battery separator so as to have a ratio of 100 ml and stirred to dissolve the fine fibrous cellulose. The obtained solution is filtered to remove the residue, and then dropped into water to obtain regenerated cellulose. This regenerated cellulose is obtained by dissolving fine fibrous cellulose in a copper ethylenediamine solution and regenerating it in water. The obtained regenerated cellulose is filtered off, sufficiently washed with water, and dried.
  • the dry weight of the obtained regenerated cellulose is measured.
  • the content of the fine fibrous cellulose contained in the battery separator is determined from this weight and the weight of the battery separator used to obtain this weight.
  • the coating layer contains fine particles.
  • the fine particles described above can be listed as the fine particles, and inorganic fine particles are preferable. Preferred specific examples are as described above.
  • the thickness of the coating layer varies depending on the pore diameter and thickness on the substrate side, but is preferably 0.1 ⁇ m or more, more preferably 0.5 ⁇ m or more, and 1 ⁇ m or more, for example. Is more preferable. Further, it is preferably 20 ⁇ m or less, more preferably 15 ⁇ m or less, and further preferably 10 ⁇ m or less.
  • the battery separator includes a base material.
  • the base material is stable with respect to the electrolytic solution, and is preferably a porous base material.
  • the constituent material of the substrate include, for example, cellulose, modified cellulose (such as carboxymethyl cellulose), polyolefin (polypropylene (PP), polyethylene (PE), and copolymerized polyolefin having a structural unit derived from ethylene of 85 mol% or more. Etc.), polyester (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.), polyacrylonitrile (PAN), aramid, polyamideimide, polyimide and other resins; glass, alumina, silica, etc.
  • An inorganic material is mentioned.
  • the constituent material of the substrate is preferably a polyolefin resin, and more preferably polypropylene or polyethylene.
  • the substrate is particularly preferably a nonwoven fabric or film made of polypropylene or polyethylene.
  • the base material is a non-woven fabric made of polyethylene
  • the polyethylene fibers are preferably oriented randomly.
  • the film is preferably a stretched film, and more preferably a biaxially stretched film.
  • the battery separator substrate may have an adhesive.
  • the battery separator substrate has an adhesive, it is preferable to contain an acrylic resin as the adhesive.
  • the acrylic resin include an ethylene- (meth) acrylic resin and a propylene- (meth) acrylic resin.
  • the adhesive is preferably sprayed on the surface of the substrate, and is preferably present in the surface layer region of the substrate. Such an adhesive acts to increase the adhesion between the substrate and the coating layer. Moreover, other resin can also be used together as needed.
  • Resins that can be used in combination include vinyl chloride resin, (meth) acrylic ester resin, styrene / acrylic ester copolymer resin, vinyl acetate resin, vinyl acetate / (meth) acrylic ester copolymer resin, urethane resin, Examples thereof include silicone resins, epoxy resins, ethylene / vinyl acetate copolymer resins, polyester resins, polyvinyl alcohol resins, ethylene vinyl alcohol copolymer resins, and rubber emulsions such as SBR and NBR.
  • the basis weight of the substrate is preferably 10 g / m 2 or more, and more preferably 20 g / m 2 or more.
  • the basis weight of the substrate is preferably 100 g / m 2 or less, more preferably 80 g / m 2 or less.
  • the density of the substrate is preferably 0.1 g / cm 3 or more, more preferably 0.2 g / cm 3 or more, and further preferably 0.3 g / cm 3 or more.
  • the density of the substrate is preferably 3.0 g / cm 3 or less, more preferably 2.0 g / cm 3 or less, and further preferably 1.0 g / cm 3 or less.
  • the battery separator manufacturing process preferably includes a step of applying the battery separator coating liquid to at least one surface of the substrate and a step of drying the substrate coated with the battery separator coating liquid.
  • a conventionally known coating machine can be used. Examples of the coating machine include a die coater, a gravure coater, a reverse roll coater, a squeeze roll coater, a curtain coater, a blade coater, and a knife coater.
  • the battery separator coating solution is preferably applied to one side of the substrate.
  • the coating amount (coating layer basis weight) of the battery separator coating liquid is preferably 1 g / m 2 or more, and more preferably 1.5 g / m 2 or more. Further, the coating amount of the battery separator coating liquid is preferably 50 g / m 2 or less, and more preferably 20 g / m 2 or less.
  • the battery separator of the present invention is preferably used for an electrochemical element typified by a lithium secondary battery.
  • an electrochemical element it can be used for applications such as supercapacitors as well as lithium batteries (primary batteries and secondary batteries) using organic electrolytes.
  • Lithium secondary batteries can be in the form of cylinders (such as square cylinders or cylinders) that use steel cans or aluminum cans as exterior canisters, or soft package forms that use metal-deposited laminated films as exterior bodies. You can also.
  • the members constituting the lithium ion battery can be roughly divided into a positive electrode, a negative electrode, a separator, and an electrolytic solution.
  • Each of the positive electrode and the negative electrode contains an active material that performs an oxidation / reduction reaction for sending and receiving electrons.
  • the positive electrode and the negative electrode can be used in the form of an electrode group having a laminated structure laminated via a battery separator, or an electrode group having a wound structure in which this is wound.
  • the positive electrode is not particularly limited as long as it is a positive electrode used in a conventionally known lithium secondary battery.
  • the positive electrode contains an active material capable of occluding and releasing Li + ions.
  • the negative electrode is not particularly limited as long as it is a negative electrode used in a conventionally known lithium secondary battery.
  • the negative electrode contains an active material capable of occluding and releasing Li + ions.
  • the positive electrode and the negative electrode can be used in the form of an electrode group having a laminated structure laminated via the battery separator of the present invention, or an electrode group having a wound structure obtained by winding the electrode group.
  • the electrolytic solution a solution in which a lithium salt is dissolved in an organic solvent is used.
  • the lithium salt is not particularly limited as long as it dissociates in a solvent to form Li + ions and does not cause a side reaction such as decomposition in a voltage range used as a battery.
  • the organic solvent is not particularly limited as long as it dissolves a lithium salt and does not cause a side reaction such as decomposition in a voltage range used as a battery.
  • Lithium-ion batteries have been known for many years in addition to power supplies for portable devices such as mobile phones and notebook personal computers, electric vehicles, hybrid vehicles, electric motorcycles, electric assist bicycles, electric tools, shavers, etc. It is used for various applications.
  • Impregnated kraft pulp with a dry mass of 100 parts by weight is impregnated with a mixed aqueous solution of ammonium dihydrogen phosphate and urea, and compressed to 49 parts by weight of ammonium dihydrogen phosphate and 130 parts by weight of urea.
  • the obtained chemical solution-impregnated pulp was dried with a dryer at 105 ° C. to evaporate the moisture and pre-dried. Then, it heated for 10 minutes with the ventilation dryer set to 140 degreeC, the phosphate group was introduce
  • the step of obtaining 100 g of the obtained phosphorylated pulp by pulp mass, pouring 10 L of ion exchange water, stirring and dispersing uniformly, and then performing filtration and dehydration to obtain a dehydrated sheet was repeated twice.
  • the obtained dehydrated sheet was diluted with 10 L of ion-exchanged water, and a 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 or more and 13 or less. Thereafter, the pulp slurry was dehydrated to obtain a dehydrated sheet, and then 10 L of ion exchange water was added.
  • the step of stirring and dispersing uniformly, followed by filtration and dehydration to obtain a dehydrated sheet was repeated twice.
  • the step of introducing phosphate groups and the step of filtration and dehydration were repeated for the obtained dehydrated sheet to obtain a twice-phosphorylated cellulose dehydrated sheet 1.
  • the infrared absorption spectrum of the obtained dehydrated sheet 1 was measured by FT-IR. As a result, absorption based on phosphate groups was observed at 1230 cm ⁇ 1 or more and 1290 cm ⁇ 1 or less, and addition of phosphate groups was confirmed.
  • Ion exchange water was added to the obtained dehydrated sheet 1 (double phosphorylated cellulose) to prepare a slurry having a solid content concentration of 2% by mass.
  • This slurry was processed three times at a pressure of 200 MPa with a wet atomization apparatus (manufactured by Sugino Machine Co., Ltd., an optimizer) to obtain fine fibrous cellulose 1. It was confirmed by X-ray diffraction that this fine fibrous cellulose 1 maintained the cellulose I type crystal.
  • a fine fibrous cellulose 2 was obtained in the same manner as the production of the fine fibrous cellulose 1 except that the number of pressure treatments of 200 MPa in the wet atomization apparatus was changed to two. It was confirmed by X-ray diffraction that the fine fibrous cellulose 2 maintained the cellulose I type crystal.
  • a fine fibrous cellulose 3 was obtained in the same manner as in the production of the fine fibrous cellulose 1 except that the number of pressure treatments of 200 MPa in the wet atomization apparatus was changed to six. It was confirmed by X-ray diffraction that the fine fibrous cellulose 3 maintained the cellulose I type crystal.
  • this pulp slurry is dehydrated to obtain a dehydrated sheet, and then, 5000 parts by mass of ion-exchanged water is poured, stirred and dispersed uniformly, and then subjected to filtration and dehydration to obtain a dehydrated sheet 2 twice. Repeated.
  • the obtained dehydration sheet 2 was measured for infrared absorption spectrum by FT-IR. As a result, absorption based on a carboxyl group was observed at 1730 cm ⁇ 1 , confirming the addition of a carboxyl group.
  • TEMPO oxidized cellulose fine fibrous cellulose was prepared.
  • Ion exchange water was added to the obtained dehydrated sheet 2 (TEMPO oxidized cellulose) to prepare a slurry having a solid content concentration of 2% by mass.
  • This slurry was processed three times at a pressure of 245 MPa with a wet atomizer (manufactured by Sugino Machine Co., Ltd., an optimizer) to obtain fine fibrous cellulose 4.
  • a wet atomizer manufactured by Sugino Machine Co., Ltd., an optimizer
  • ⁇ Manufacture of fine fibrous cellulose A (for comparative example)> ⁇ Alkaline TEMPO oxidation treatment> Undried softwood bleached kraft pulp equivalent to 100 parts by weight of dry matter, 1.25 parts by weight of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), 12.5 parts by weight of sodium bromide, was dispersed in 10,000 parts by mass of water. Subsequently, 13 mass% sodium hypochlorite aqueous solution was added so that the quantity of sodium hypochlorite might be 8.0 mmol with respect to 1.0 g of pulp, and reaction was started. During the reaction, a 0.5 M aqueous sodium hydroxide solution was added dropwise to maintain the pH at 10 or more and 11 or less, and the reaction was regarded as complete when no change in pH was observed.
  • this pulp slurry is dehydrated to obtain a dehydrated sheet, and then the process of pouring 5000 parts by mass of ion exchange water, stirring and dispersing uniformly, and then dehydrating by filtration to obtain a dehydrated sheet is repeated twice. It was.
  • the obtained dehydration sheet 3 was measured for infrared absorption spectrum by FT-IR. As a result, absorption based on a carboxyl group was observed at 1730 cm ⁇ 1 , confirming the addition of a carboxyl group.
  • this dehydration sheet 3 (TEMPO oxidized cellulose), fine fibrous cellulose was prepared.
  • Ion exchange water was added to the obtained dehydrated sheet 3 (TEMPO oxidized cellulose) to prepare a slurry having a solid content concentration of 2% by mass.
  • This slurry was treated three times at a pressure of 245 MPa with a wet atomization apparatus (manufactured by Sugino Machine, Optimizer) to obtain fine fibrous cellulose A. It was confirmed by X-ray diffraction that this fine fibrous cellulose A maintained the cellulose I type crystal.
  • Carboxymethylcellulose (Daiichi Kogyo Seiyaku, BSH-6, viscosity 7000 mPa ⁇ s measured under the following conditions) and xanthan gum (Tokyo Chemical Industry Co., Ltd.) were each made into a 2% by mass aqueous solution using ion-exchanged water. .
  • CMC carboxymethyl cellulose
  • the fiber width of the fine fibrous cellulose was measured by the following method.
  • the supernatant of the fine fibrous cellulose treated with the wet atomization apparatus was diluted with water so that the concentration of the fine fibrous cellulose was 0.01% by mass or more and 0.1% by mass or less, and subjected to a hydrophilic treatment. It was dripped on the carbon grid film. After drying, it was stained with uranyl acetate and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.). It was confirmed that the fine fibrous cellulose 1 to 4 and the fine fibrous cellulose A were fine fibrous cellulose having a fiber width of about 4 nm.
  • the introduction amount of the substituent is the introduction amount of the phosphoric acid group or carboxylic acid group to the fiber raw material. The larger this value, the more phosphoric acid groups or carboxylic acid groups are introduced.
  • the amount of substituent introduced was measured by diluting the target fine fibrous cellulose with ion-exchanged water so that the content was 0.2% by mass, and then treating with ion-exchange resin and titration with alkali. In the treatment with an ion exchange resin, 1/10 by volume of a strongly acidic ion exchange resin (Amberjet 1024; Organo Co., Ltd., conditioned) is added to the 0.2 mass% fibrous cellulose-containing slurry and shaken for 1 hour.
  • a strongly acidic ion exchange resin Amberjet 1024; Organo Co., Ltd., conditioned
  • the degree of polymerization was calculated from the mass of the absolutely dry fine fibrous cellulose used for the measurement, the solvent dropping time, and the dropping time of the fine fibrous cellulose solution using the following equation.
  • the following average degree of polymerization is an average value of the values measured three times.
  • TI value ⁇ 1 / ⁇ 2 eta 1: Shear viscosity was measured at a rate of 1 sec -1 eta 2: viscosity measured under the conditions of a shear rate of 1,000 sec -1
  • boehmite (AlOOH) powder was suspended in ion-exchanged water, it was finely pulverized using a wet ball mill until the particle size became 1 ⁇ m or less to obtain finely pulverized boehmite slurry.
  • Ion exchange water was added so that the composition of the finely pulverized boehmite slurry was 51 parts by mass with respect to 100 parts by mass of boehmite.
  • 50 g of a suspension of fine fibrous cellulose 1 having a solid content concentration of 2 mass% (a suspension of 1 g of solid fibrous cellulose 1 and 49 g of water) was added.
  • K The mixture was stirred for 1 hour at 3000 rpm with a homodisper (manufactured by Koki Kogyo Kogyo) to obtain a battery separator coating solution.
  • Example 2 Ion exchange water is added so that the composition of the finely pulverized boehmite slurry is 65.7 parts by mass of ion exchange water with respect to 100 parts by mass of boehmite, and the fine fibrous cellulose 1 having a solid content concentration of 2% by mass is obtained.
  • a separator coating solution for a battery was obtained in the same manner as in Example 1 except that the amount of the suspension was 35 g (solid content of fine fibrous cellulose 1 0.7 g, water 34.3 g).
  • Example 3 Ion exchange water is added so that the composition of the finely pulverized boehmite slurry is 80.4 parts by mass of ion exchange water with respect to 100 parts by mass of boehmite, and the fine fibrous cellulose 1 having a solid content concentration of 2% by mass.
  • a separator coating solution for a battery was obtained in the same manner as in Example 1 except that the amount of the suspension was changed to 20 g (solid content of fine fibrous cellulose 1 0.4 g, water 19.6 g).
  • Example 4 A battery separator coating solution was obtained in the same manner as in Example 1 except that barium titanate powder was used instead of boehmite (AlOOH) powder.
  • Example 5 A battery separator coating solution was obtained in the same manner as in Example 1 except that lithium phosphate powder was used instead of boehmite (AlOOH) powder.
  • Example 6 A battery separator coating solution was obtained in the same manner as in Example 1 except that the fine fibrous cellulose 2 was used instead of the fine fibrous cellulose 1.
  • Example 7 A battery separator coating solution was obtained in the same manner as in Example 1 except that the fine fibrous cellulose 3 was used instead of the fine fibrous cellulose 1.
  • Example 8> A battery separator coating solution was obtained in the same manner as in Example 1 except that fine fibrous cellulose 4 was used instead of fine fibrous cellulose 1.
  • Example 2 A battery separator coating solution was prepared in the same manner as in Example 1, except that carboxymethylcellulose (BSH-6, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., viscosity 7000 mPa ⁇ s measured under the above conditions) was used instead of fine fibrous cellulose 1. Obtained.
  • carboxymethylcellulose BSH-6, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., viscosity 7000 mPa ⁇ s measured under the above conditions
  • Example 3 A battery separator coating solution was obtained in the same manner as in Example 1 except that xanthan gum (manufactured by Tokyo Chemical Industry Co., Ltd.) was used in place of the fine fibrous cellulose 1.
  • Polyethylene fiber (fiber length: 5 mm, fiber strength: 28 cN / dtex, elastic modulus: 900 cN / dtex) is dispersed in water so as to be 0.2% by mass, and a randomly oriented web is formed by wet papermaking. did.
  • the nonwoven fabric After spraying so that it might become 10 mass% in ratio, it dried with the hot air dryer set to 110 degreeC, and the nonwoven fabric of 30 g / m ⁇ 2 > was obtained.
  • the nonwoven fabric was calendered to obtain a nonwoven fabric having a density of 0.64 g / cm 3 . This non-woven fabric was used as a non-woven fabric substrate for applying a battery separator coating solution.
  • a battery separator coating solution was applied to the nonwoven fabric substrate so that the basis weight of the coating layer after drying was 5 g / m 2 to prepare a battery separator.
  • the battery separator coating liquid obtained in the examples is excellent in fine particle dispersibility.
  • the battery separator coating liquid obtained in the examples had good coating properties.
  • the battery separator coating solution obtained in the comparative example was inferior in fine particle dispersibility. Further, in the battery separator produced by applying the battery separator coating liquid obtained in the comparative example, the back-through of the coating liquid occurred.

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Abstract

La présente invention aborde le problème consistant à fournir un liquide de revêtement pour séparateurs de batterie qui présente d'excellentes propriétés de revêtement et d'excellentes propriétés de dispersion de particules fines. La présente invention concerne un épaississant qui doit être utilisé dans un liquide de revêtement pour séparateurs de batterie, qui comprend de la cellulose fibreuse ayant une largeur de fibre de 1 000 nm ou moins, et présente une valeur d'indice thixotropique (valeur TI) de 100 ou plus telle que calculée selon la condition a. (Condition a) Une suspension est obtenue par dilution avec de l'eau désionisée de façon à obtenir une concentration de 0,4 % en masse de cellulose fibreuse ayant une largeur de fibre de 1 000 nm ou moins dans l'épaississant à utiliser dans un liquide de revêtement pour des séparateurs de batterie ; et la valeur d'indice thixotropique (valeur TI) de l'épaississant à utiliser dans un liquide de revêtement pour des séparateurs de batterie est égal à η1/η2, étant donné que la viscosité de la suspension est mesurée à l'aide d'un rhéomètre, la viscosité mesurée dans des conditions d'une température de mesure de 23 °C, avec un temps de mesure de 5 minutes, et une vitesse de cisaillement de 1 sec-1 est η1, et la viscosité mesurée dans des conditions d'une température de mesure de 23 °C, avec un temps de mesure de 5 minutes, et une vitesse de cisaillement de 1 000 sec-1 est η2.
PCT/JP2017/036998 2016-10-14 2017-10-12 Épaississant utilisé dans un liquide de revêtement pour séparateurs de batterie, liquide de revêtement pour séparateurs de batterie, et séparateur de batterie Ceased WO2018070473A1 (fr)

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US20210257702A1 (en) * 2018-08-30 2021-08-19 Panasonic Intellectual Property Management Co., Ltd. Nonaqueous electrolyte secondary battery
WO2022059678A1 (fr) 2020-09-17 2022-03-24 昭和電工株式会社 Composition de fluide de revêtement, substrat avec film de revêtement, séparateur, batterie secondaire et matériau d'électrode
WO2022059677A1 (fr) 2020-09-17 2022-03-24 昭和電工株式会社 Composition liquide de revêtement, substrat avec film de revêtement, séparateur, batterie secondaire et matériau d'électrode
WO2022080280A1 (fr) 2020-10-13 2022-04-21 昭和電工株式会社 Composition de revêtement, et substrat avec film de revêtement
WO2022080281A1 (fr) 2020-10-13 2022-04-21 昭和電工株式会社 Composition de revêtement, substrat avec film de revêtement, séparateur, batterie secondaire, batterie secondaire au lithium-ion, et matériau d'électrode
JP2023040759A (ja) * 2021-09-10 2023-03-23 株式会社日本製鋼所 塗工液、多孔質フィルム、リチウムイオン電池、塗工液の製造方法、多孔質フィルムの製造方法およびリチウムイオン電池の製造方法

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JPWO2019225629A1 (ja) * 2018-05-23 2021-06-17 関西ペイント株式会社 光輝性顔料分散体及び複層塗膜形成方法
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JP7286632B2 (ja) 2018-05-23 2023-06-05 関西ペイント株式会社 光輝性顔料分散体及び複層塗膜形成方法
CN112236491B (zh) * 2018-05-23 2023-05-05 关西涂料株式会社 效应颜料分散体及多层涂膜形成方法
WO2019225629A1 (fr) * 2018-05-23 2019-11-28 関西ペイント株式会社 Dispersion de pigment brillant et procédé de formation d'un film de revêtement multicouche
US20210257702A1 (en) * 2018-08-30 2021-08-19 Panasonic Intellectual Property Management Co., Ltd. Nonaqueous electrolyte secondary battery
KR20230054865A (ko) 2020-09-17 2023-04-25 가부시끼가이샤 레조낙 도공액 조성물, 도공막 구비 기재, 세퍼레이터, 이차 전지 및 전극 재료
WO2022059678A1 (fr) 2020-09-17 2022-03-24 昭和電工株式会社 Composition de fluide de revêtement, substrat avec film de revêtement, séparateur, batterie secondaire et matériau d'électrode
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KR20230054864A (ko) 2020-09-17 2023-04-25 가부시끼가이샤 레조낙 도공액 조성물, 도공막 구비 기재, 세퍼레이터, 이차 전지 및 전극 재료
TWI779871B (zh) * 2020-10-13 2022-10-01 日商昭和電工股份有限公司 塗工組成物、附塗工膜之基材、分隔器、二次電池、鋰離子二次電池及電極材料
JPWO2022080280A1 (fr) * 2020-10-13 2022-04-21
JPWO2022080281A1 (fr) * 2020-10-13 2022-04-21
KR20230064627A (ko) 2020-10-13 2023-05-10 가부시끼가이샤 레조낙 도공 조성물, 도공막 구비 기재, 세퍼레이터, 이차 전지, 리튬 이온 이차 전지 및 전극 재료
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WO2022080281A1 (fr) 2020-10-13 2022-04-21 昭和電工株式会社 Composition de revêtement, substrat avec film de revêtement, séparateur, batterie secondaire, batterie secondaire au lithium-ion, et matériau d'électrode
CN116323831A (zh) * 2020-10-13 2023-06-23 株式会社力森诺科 涂布组合物和带涂膜的基材
WO2022080280A1 (fr) 2020-10-13 2022-04-21 昭和電工株式会社 Composition de revêtement, et substrat avec film de revêtement
JP2023040759A (ja) * 2021-09-10 2023-03-23 株式会社日本製鋼所 塗工液、多孔質フィルム、リチウムイオン電池、塗工液の製造方法、多孔質フィルムの製造方法およびリチウムイオン電池の製造方法

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