WO2021117662A1 - Cellulose nanocrystal dispersion liquid and cellulose nanocrystal-containing coating liquid - Google Patents

Cellulose nanocrystal dispersion liquid and cellulose nanocrystal-containing coating liquid Download PDF

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WO2021117662A1
WO2021117662A1 PCT/JP2020/045413 JP2020045413W WO2021117662A1 WO 2021117662 A1 WO2021117662 A1 WO 2021117662A1 JP 2020045413 W JP2020045413 W JP 2020045413W WO 2021117662 A1 WO2021117662 A1 WO 2021117662A1
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cellulose
cellulose nanocrystal
dispersion
mass
treatment
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Japanese (ja)
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英昭 長▲浜▼
友貴 木下
慎一郎 前田
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東洋製罐グループホールディングス株式会社
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    • 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
    • C08B15/02—Oxycellulose; Hydrocellulose; Cellulosehydrate, e.g. microcrystalline cellulose
    • 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
    • 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
    • C08B5/14—Cellulose sulfate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C08K3/36—Silica
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/10—Esters; Ether-esters
    • C08K5/11—Esters; Ether-esters of acyclic polycarboxylic acids
    • 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
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
    • C08L29/02—Homopolymers or copolymers of unsaturated alcohols
    • C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D101/00—Coating compositions based on cellulose, modified cellulose, or cellulose derivatives
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D101/00—Coating compositions based on cellulose, modified cellulose, or cellulose derivatives
    • C09D101/02—Cellulose; Modified cellulose
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D129/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Coating compositions based on hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Coating compositions based on derivatives of such polymers
    • C09D129/02—Homopolymers or copolymers of unsaturated alcohols
    • C09D129/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/02—Emulsion paints including aerosols
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/63—Additives non-macromolecular organic

Definitions

  • the present invention relates to a cellulose nanocrystal dispersion liquid and a cellulose nanocrystal-containing coating liquid, and more specifically, cellulose capable of forming a coating film having excellent dispersibility and coatability, and excellent transparency and gas barrier property.
  • the present invention relates to a nanocrystal dispersion liquid and a cellulose nanocrystal-containing coating liquid.
  • nanocellulose is used as an advanced biomass raw material, as a functional additive, as a film composite material, and for various purposes.
  • materials such as a film made of cellulose nanofibers (CNF) and a laminate containing cellulose nanofibers can suppress the dissolution and diffusion of gas due to hydrogen bonds between cellulose fibers and strong cross-linking interactions, so that oxygen can be suppressed.
  • CNF cellulose nanofibers
  • barrier materials using cellulose nanofibers have been proposed.
  • hydrophilic functional groups such as a carboxyl group and a phosphoric acid group are introduced into the hydroxyl groups of the cellulose in addition to the mechanical treatment. The energy required for the treatment can be reduced, and the barrier property and the dispersibility in an aqueous solvent are improved.
  • a dispersion liquid using such cellulose nanofibers is also known.
  • the crystallinity is 70% or more
  • the degree of polymerization by the viscosity method using a copper ethylenediamine solution is 160 or less
  • the degree of polymerization is 160 or less.
  • a dispersion liquid in which cellulose nanofibers having a fiber diameter of 50 nm or less are dispersed in a dispersion medium has been proposed.
  • Patent Document 2 below proposes a dispersion liquid in which cellulose nanofibers having a number average fiber length of 250 nm or less and a number average fiber diameter of 2 to 5 nm are dispersed in a dispersion medium.
  • a step of preparing the cellulose nanofibers to be dispersed in the dispersion medium a step of reducing the viscosity of the cellulose nanofibers chemically treated using a TEMPO catalyst. Or, a micronization step for making nanofibers is required, and the productivity and economic efficiency are not sufficiently satisfied.
  • cellulose nanofibers are not satisfactory in terms of gas barrier properties due to their long fiber length, and it is possible to obtain high gas barrier properties by shortening the fiber length, but further treatment is required for that purpose. , Inferior in economy.
  • cellulose nanofibers having a short fiber length capable of lowering the viscosity are prepared in order to improve the dispersibility of the dispersion liquid, but specially for preparing cellulose nanofibers having a short fiber length. It is necessary to use various raw materials, which is also inferior in productivity and economy.
  • cellulose nanocrystals As nanocellulose having a shorter fiber length than cellulose nanofibers, cellulose nanocrystals (CNC) formed by hydrolyzing cellulose fibers with a strong acid are known. Since cellulose nanocrystals have a short fiber length, they are excellent in handleability at the time of coating and also excellent in smoothness of the coated surface. However, in general, cellulose nanocrystals are inferior in gas barrier properties to cellulose nanofibers into which a carboxyl group or the like has been introduced as described above. The present inventors have found that cellulose nanocrystals can exhibit excellent gas barrier properties by containing a large amount of anionic functional groups (Japanese Patent Application No. 2018-177610).
  • cellulose nanocrystals are generally solidified in the form of powder from the viewpoint of storage stability, transportability, etc., and in order to obtain a dispersion liquid, powdered cellulose nanocrystals are used as a dispersion medium while suppressing aggregation. It needs to be dispersed, and it is not satisfactory in terms of productivity and economy. Further, according to the research by the present inventors, the dispersion liquid in which such solidified (powder-like) cellulose nanocrystals are dispersed reduces the gas barrier property of the cellulose nanocrystals containing anionic functional groups. I understood.
  • an object of the present invention is to provide a cellulose nanocrystal dispersion liquid which is excellent in dispersibility of cellulose nanocrystals, can exhibit excellent barrier properties and handleability, and is also excellent in productivity and economy. ..
  • Another object of the present invention is to provide a cellulose nanocrystal-containing coating liquid capable of efficiently forming a crosslinked structure in which cellulose nanocrystals are uniformly dispersed by using a cellulose nanocrystal dispersion liquid having excellent gas barrier properties and handleability. It is to be.
  • Still another object of the present invention is to provide a molded product having a cellulose nanocrystal-containing layer having excellent gas barrier properties and interlayer adhesiveness.
  • a cellulose nanocrystal dispersion containing a sulfate group and / or a sulfo group derived from a sulfuric acid treatment and an anionic functional group derived from a hydrophilic treatment, wherein the solid content of the cellulose nanocrystals is 2% by mass.
  • a cellulose nanocrystal dispersion liquid characterized by having a visible light transmittance at 600 nm of% aqueous dispersion of 45% T or more.
  • the average particle size of the cellulose nanocrystals by the laser diffraction type particle size distribution measuring device of the cellulose nanocrystal dispersion is 10.1 ⁇ m or less, the median diameter is 10.6 ⁇ m or less, and the mode diameter is 10.9 ⁇ m or less.
  • the total amount of the sulfate group and / or the sulfo group and the anionic functional group is more than 0.17 mmol / g and 4.0 mmol / g or less.
  • the degree of crystallinity of the cellulose nanocrystal is 60% or more, the fiber diameter is 50 nm or less, and the aspect ratio is 5 to 50. 4.
  • the anionic functional group is at least one of a sulfuric acid group, a sulfo group, a phosphoric acid group, and a carboxyl group. 5.
  • the hydrophilization treatment is a combination of a never dry treatment or a never dry treatment and a treatment using any one of carbodiimide, sulfuric acid, sulfur trioxide-pyridine complex, phosphoric acid-urea, TEMPO catalyst, and oxidizing agent. , Is preferable.
  • a cellulose nanocrystal-containing coating liquid containing the above-mentioned cellulose nanocrystal dispersion liquid, a water-soluble polymer, an inorganic layered compound and a polyvalent carboxylic acid.
  • the cellulose nanocrystal-containing coating liquid of the present invention 1. 1.
  • the water-soluble polymer is polyvinyl alcohol, which is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of cellulose nanocrystals (solid content).
  • the inorganic layered compound is mica and is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of cellulose nanocrystals (solid content).
  • the polyunsaturated carboxylic acid is citric acid, which is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of cellulose nanocrystals (solid content). Is preferable.
  • the molded product is further formed by forming a layer containing a polyvalent cationic resin and a cellulose nanocrystal on a base material, and the cellulose nanocrystal (solid content) is 1.0 g / m 2 of the above.
  • a molded article having an oxygen permeability (23 ° C., 50% RH) of less than 3.8 cc / m 2, day, atm when contained in an amount of.
  • the cellulose nanocrystals having a short fiber length and a small fiber diameter are uniformly dispersed without agglomeration, so that they are excellent in coatability and handleability and are transparent. It is also excellent in properties, and has excellent transparency with a visible light transmittance of 45% T or more in an aqueous dispersion in which the solid content of the cellulose nanocrystal is 2% by mass.
  • the cellulose nanocrystals have a sulfuric acid group and / or a sulfo group derived from the sulfuric acid treatment and an anionic functional group derived from the hydrophilic treatment, and are densely self-assembled by charge repulsion between the cellulose nanocrystals. Since the structure is formed, excellent gas barrier properties can be exhibited. Further, since it is composed of cellulose nanocrystals having a short fiber length and these are uniformly dispersed in the dispersion liquid, the gas barrier property is further improved in combination with the above-mentioned self-assembled structure.
  • the cellulose nanocrystal dispersion liquid of the present invention is more transparent (visible light transmission) than the dispersion liquid in which solidified cellulose nanocrystals are dispersed as the same solid content. Excellent rate) and gas barrier properties. Further, it is not necessary to redisperse the solidified cellulose nanocrystals to prepare a dispersion liquid, which is excellent in terms of economy and handleability. Further, in the present invention, it is particularly preferable that the cellulose nanocrystals are never-dried without undergoing drying and solidification, whereby the cellulose nanocrystals can be used as a dispersion liquid in a fine and homogeneous dispersed state. can do.
  • the cellulose nanocrystal-containing coating liquid of the present invention by using the above-mentioned cellulose nanocrystal dispersion liquid, it is possible to prepare a coating liquid capable of forming a coating film having good productivity and economy and excellent gas barrier property. it can. Further, as described above, since the cellulose nanocrystals having a short fiber length are not aggregated and the dispersion liquid is uniformly dispersed, the handling property at the time of coating is excellent and the smoothness of the coating surface is also excellent. ing. In addition, the obtained coating film has excellent gas barrier properties.
  • the cellulose nanocrystal-containing coating liquid of the present invention contains excellent gas barrier properties due to the hydroxyl group of the cellulose nanocrystal and the polyvalent carboxylic acid forming a dense crosslinked film, and contains a water-soluble polymer and an inorganic layered compound. Combined with the improvement of gas barrier property based on the presence, it becomes possible to exhibit excellent gas barrier property even under high humidity conditions. Further, in the molded product in which the layer containing the polyvalent cationic resin and the cellulose nanocrystals of the present invention is formed, the polyvalent value between the cellulose nanocrystals is maintained while maintaining the dense self-assembled structure between the cellulose nanocrystals. Since the cation resin is naturally diffused and intervened in a mixed state, and the self-assembled structure of nanocellulose is further strengthened by the polyvalent cation, the gas barrier is superior to the gas barrier property expressed only by nanocellulose. Has sex.
  • cellol nanocrystals containing a sulfate group and / or a sulfo group derived from a sulfuric acid treatment and an anionic functional group derived from a hydrophilization treatment are uniform without agglomeration in the dispersion medium. Since it is a dispersion liquid dispersed in, it has excellent transparency with a visible light transmittance of 45% T or more in an aqueous dispersion having a solid content of 2% by mass of cellulose nanocrystals.
  • the gas barrier property of the cellulose nanocrystals is expressed by the self-assembled structure formed by the charge repulsion between the cellulose nanocrystals acting as a barrier of the permeation path of the permeated gas.
  • anionic functional groups such as sulfate group and / or sulfo group and carboxyl group are present on the surface of the cellulose nanocrystal, the self-assembled structure is made efficient by the charge (anion) possessed by these anionic functional groups. It is well formed and can exhibit excellent gas barrier properties in combination with the above-mentioned uniform dispersibility.
  • the average particle size of the cellulose nanocrystals by the laser diffraction type particle size distribution measuring device is 10.1 ⁇ m or less, the median diameter is 10.6 ⁇ m or less, and the mode diameter is 10.9 ⁇ m or less. Is preferable.
  • the particle size distribution means that particles of what size (particle size) are included in the sample particle group of the dispersion liquid to be measured, and at what ratio (relative particle amount with the whole as 100%). It is an index showing whether or not it is.
  • the particle size is specified from the light intensity distribution data pattern by the laser diffraction / scattering method using a laser diffraction type particle size distribution device, and the volume-based particle size distribution is obtained by calculation. It is also possible to calculate the number-based particle size distribution based on the volume-based particle size distribution.
  • the laser diffraction type particle size distribution measuring device when the particle group to be measured is irradiated with laser light, a light intensity distribution pattern of diffracted / scattered light is spatially generated, and the light intensity distribution pattern of the forward scattered light is a lens. A ring-shaped diffracted / scattered image is formed on the detection surface at the focal distance. This is detected by a ring sensor in which detection elements are arranged concentrically.
  • the side scattered light and the backscattered light are detected by the side scattered light sensor and the backscattered light sensor, respectively.
  • the light intensity distribution pattern is detected using various detection elements, and the light intensity distribution data is obtained.
  • the average particle size, median diameter, and mode diameter of the cellulose nanocrystals can be obtained by analyzing the measurement results of the laser diffraction type particle size distribution device in a state where the cellulose nanocrystals in the dispersion liquid are present at a dilute concentration. ..
  • the dispersibility is good, the gas barrier property and the handling property at the time of coating are excellent, and the coating surface is excellent. It also has the advantage of being excellent in smoothness.
  • the particle size distribution is usually expressed as a particle size (integration or frequency) relative to the particle size scale.
  • the particle size distribution can be obtained based on the light intensity distribution pattern of the diffraction / scattered light calculated on the assumption that the particles are spherical. .. Therefore, the particle size distribution measurement is always based on the assumption or assumption that the particles are spherical.
  • the obtained particle size distribution is such that the minor axis of the fibrous particles corresponds to the lower limit of the distribution and the major axis substantially corresponds to the upper limit of the distribution.
  • the distribution range of the measurement result extends from the smallest minor axis to the largest major axis, and even in the case of fibrous particles, the particles to be measured.
  • the particle size distribution shifts to the smaller one as a whole. If the fibrous particles are agglomerated, the particle size distribution moves to the larger side as a whole, and if they are dispersed, the particle size distribution moves to the smaller side as a whole. In this way, the fiber characteristics of the cellulose nanocrystals can be quantitatively evaluated by the laser diffraction type particle size distribution measuring device.
  • the particle size distribution data is expressed as an integrated% or frequency% with respect to the particle size scale, but can also be expressed as a particle size with respect to the integrated% scale.
  • the particle size at the point where the integrated% distribution curve intersects the 10% horizontal axis intersects with the 10% diameter and the particle size at the point where the 50% horizontal axis intersects with the 50% diameter and 90% horizontal axis.
  • the particle size of the point can be said to be 90%, and an arbitrary integrated% is used if necessary.
  • the calculation method of the arbitrary% particle size is shown in FIG. 1 and the following formulas (3) and (4).
  • any% particle size x a in cumulative% Q a when cumulative% Q j + 1 and Q j in the x 2 one particle size on either side of a x j + 1 and x j are known, any% in cumulative% Q a
  • the particle size x a can be calculated using the above equations (3) and (4).
  • the 50% particle size becomes the median diameter, and the median diameter can be obtained by calculating with Q a as 50%. Further, the mode diameter can be obtained from the particle size having the largest ratio of appearance frequency (%).
  • the cellulose nanocrystals have undergone the never dry treatment, but the cellulose nanocrystals in the cellulose nanocrystal dispersion have undergone the never dry treatment. Or, whether or not the cellulose nanocrystal dispersion has undergone the dry solidification treatment can be evaluated by relaxation time measurement analysis by pulse NMR and cryo-SEM observation for the difference in molecular motility and dispersibility of the cellulose nanocrystal dispersion.
  • the free induction decay (M (t)) measured by the solid echo method of pulse NMR using Bruker's TD-NMR THE MINISPEC MQ20 was carried out using the following formula (5).
  • Fitting with analysis software (TDNMR-A) and analyze by approximating one component ( ⁇ ) (component ( ⁇ ): the component with low molecular motion and the lowest molecular motion in which molecular motion is constrained). Can be done.
  • two or more components component ( ⁇ ), component ( ⁇ ): a component having higher molecular motility than the component ( ⁇ ) and whose molecular motion is not constrained).
  • Component ( ⁇ ): A component with higher motility than component ( ⁇ )) can be examined, and if an error is returned on the analysis software, it is suggested that two or more components do not exist.
  • the dispersion obtained by concentrating the cellulose nanocrystals by the never-dry treatment is a dispersion treated by spray-drying or the like and then redispersed using a disperser (described later). It becomes a dispersion liquid having higher viscosity and transparency than (corresponding to Comparative Example 1). That is, as is clear from the results of Examples described later, in Example 1, which is a cellulose nanocrystal dispersion liquid obtained by never-drying, as a result of analysis according to the above formulas (5) to (7), the relaxation time is short. The analysis result of the numerical value with only one component ( ⁇ ) is obtained.
  • Comparative Example 1 which is a cellulose nanocrystal dispersion liquid that has been solidified by a drying treatment
  • the component ( ⁇ ) having a short relaxation time and the relaxation time Numerical analysis results for the two components of the longer component ( ⁇ ) have been obtained.
  • the cellulose nanocrystal has a total amount of anionic functional groups such as sulfate group and / or sulfo group and carboxyl group of more than 0.17 mmol / g and 4.0 mmol / g or less. It is preferable that the mixture is contained, and when the total amount of anionic functional groups is smaller than the above range, a sufficient self-assembled structure is not formed as compared with the case where the total amount of anionic functional groups is in the above range, and a desired gas barrier is not formed. There is a risk that sex cannot be obtained.
  • a sulfuric acid group is a concept including a sulfuric acid ester group.
  • the cellulose nanocrystal is a cellulose nanocrystal hydrolyzed by sulfuric acid treatment, it already contains a sulfuric acid group and / or a sulfo group that contributes to the formation of a self-assembled structure.
  • cellulose nanocrystals acid-hydrolyze cellulose fibers by sulfuric acid treatment or hydrochloric acid treatment, but since cellulose nanocrystals by hydrochloric acid treatment do not have sulfuric acid groups and / or sulfo groups, they have a self-assembled structure.
  • the anionic functional group contained in the cellulose nanocrystal of the present invention is determined by the method for hydrophilizing the cellulose nanocrystal described later, and is particularly preferably a carboxyl group, a phosphoric acid group, a sulfate group and / or a sulfo group. .. As a result, the above-mentioned self-organizing structure is efficiently formed, and the gas barrier property is improved.
  • the total amount of the sulfate group and / or the sulfo group and the anionic functional group of the cellulose nanocrystal is in the above range and the crystallinity is in the range of 60% or more.
  • the cellulose nanocrystal is preferably a cellulose nanocrystal having a fiber diameter of 50 nm or less and an aspect ratio of 5 to 50.
  • the cellulose nanocrystal dispersion liquid of the present invention having the above-mentioned characteristics is a cellulose nanocrystal dispersion liquid that has not undergone solidification such as powder (never dry treatment).
  • solidification such as powder (never dry treatment).
  • the cellulose nanocrystals that have been subjected to the drying treatment and solidified are difficult to align the fibers in the dispersion liquid, and it is difficult to form a dense self-assembled structure, as compared with the dispersion liquid of the present invention. Poor gas barrier property. Therefore, in the cellulose nanocrystal dispersion of the present invention, a cellulose nanocrystal containing a sulfuric acid group and / or a sulfo group obtained by treating a cellulose raw material with sulfuric acid is hydrophilized, and after the hydrophilization treatment step, centrifugation is performed. It is a dispersion obtained by subjecting it to a step and a filtration separation step, and does not undergo a spray drying step or the like for solidification.
  • Cellulose nanocrystals are rod-shaped cellulose crystal fibers obtained by acid-hydrolyzing cellulose fibers such as pulp with sulfuric acid or hydrochloric acid, but in the present invention, they can contribute to the formation of a self-assembled structure. Sulfuric acid-treated cellulose nanocrystals with sulfuric acid and / or sulfo groups are used. Cellulose nanocrystals preferably contain a sulfate group and / or a sulfo group in an amount of 0.18 to 4.0 mmol / g, particularly 0.20 to 2.0 mmol / g.
  • the cellulose nanocrystals have a fiber diameter of 50 nm or less, particularly in the range of 2 to 50 nm, a fiber length in the range of 100 to 500 nm, an aspect ratio in the range of 5 to 50, and a degree of crystallinity. 60% or more, particularly 70% or more can be preferably used.
  • the amount of sulfate group and / or sulfo group is adjusted or anions such as carboxyl group and phosphoric acid group are adjusted by hydrophilizing the cellulose nanocrystal having a sulfate group and / or sulfo group described above.
  • a sex functional group is introduced into the hydroxyl group at the 6-position of cellulose, and the total amount of anionic functional groups such as sulfate group, sulfo group, carboxyl group and phosphoric acid group is more than 0.17 mmol / g and 4.0 mmol / g or less.
  • cellulose nanocrystals in the range of 0.20 to 2.0 mmol / g are prepared.
  • the hydrophilization treatment is a combination of a never-dry treatment or a never-dry treatment and a treatment using any of water-soluble carbodiimide, sulfuric acid, sulfur trioxide-pyridine complex, phosphoric acid-urea, TEMPO catalyst, and oxidant.
  • Treatment with any of carbodiimide, sulfuric acid, and sulfur trioxide-pyridine complex adjusts the amount of sulfuric acid group and / or sulfo group of the cellulose nanocrystal, and further shortens the nanocellulose.
  • an anionic functional group of a phosphoric acid group or a carboxyl group is introduced, and the total amount of anionic functional groups of the cellulose nanocrystal is within the above range. It will be adjusted.
  • the hydrophilization treatment may be performed by any one of them as long as the total amount of anionic functional groups is within the above range, but the same treatment may be performed a plurality of times or a plurality of times in combination with other treatments. Good.
  • ⁇ Hydrophilic treatment by never dry treatment> Cellulose nanocrystals undergo drying treatments such as spray drying, heating, and reduced pressure to solidify powders and the like, but when solidified by drying treatments, some of the anionic functional groups contained in the cellulose nanocrystals are removed. Separation reduces hydrophilicity. That is, a never-drying treatment of cellulose nanocrystals containing anionic functional groups without solidification of powder or the like can be mentioned as a hydrophilic treatment.
  • the anionic functional group include a sulfate group and / or a sulfo group, a phosphoric acid group, a carboxyl group and the like.
  • ⁇ Hydrophilic treatment using carbodiimide> In the treatment using carbodiimide, cellulose nanocrystals and carbodiimide are stirred in a solvent such as dimethylformamide, sulfuric acid is added thereto, and then the reaction is carried out at a temperature of 0 to 80 ° C. for 5 to 300 minutes to obtain a sulfuric acid ester. ..
  • Carbodiimide and sulfuric acid are preferably used in an amount of 5 to 30 mmol and 5 to 30 mmol with respect to 1 g (solid content) of cellulose nanocrystals.
  • an alkaline compound such as sodium hydroxide to convert the sulfo group introduced into the cellulose nanocrystal from H type to Na type in order to improve the yield.
  • impurities and the like are removed by filtration using a dialysis membrane or the like to prepare cellulose nanocrystals modified with a sulfate group and / or a sulfo group.
  • the cellulose nanocrystals used in the present invention are formed by hydrolyzing cellulose fibers with sulfuric acid, and the cellulose nanocrystals are further hydrophilized with sulfuric acid.
  • Sulfuric acid is preferably used in an amount of 40 to 60% by mass with respect to 1 g (solid content) of cellulose nanocrystals.
  • Sulfate group and / or sulfo group-modified cellulose nanocrystals are prepared by reacting at a temperature of 40 to 60 ° C. for 5 to 300 minutes and then subjecting to filtration treatment using a dialysis membrane or the like to remove impurities and the like. To.
  • ⁇ Hydrophilic treatment using sulfur trioxide-pyridine complex In the treatment using the sulfur trioxide-pyridine complex, the cellulose nanocrystal and the sulfur trioxide-pyridine complex are reacted in dimethylsulfoxide at a temperature of 0 to 60 ° C. for 5 to 240 minutes to form 6 of the cellulose glucose unit. A sulfate group and / or a sulfo group is introduced into the hydroxyl group at the position.
  • the sulfur trioxide-pyridine complex is preferably blended in a mass of 0.5 to 4 g with respect to 1 g (solid content) of cellulose nanocrystals.
  • an alkaline compound such as sodium hydroxide to convert the sulfate group and / or the sulfo group introduced into the cellulose nanocrystal from the H type to the Na type in order to improve the yield.
  • dimethylformamide or isopropyl alcohol is added, and the mixture is washed by centrifugation or the like, impurities and the like are removed by filtration using a dialysis membrane or the like, and the obtained concentrate is dispersed in water to form a sulfate group.
  • / or a sulfo group-modified cellulose nanocrystal is prepared.
  • the hydrophilization treatment using phosphoric acid-urea can be carried out in the same manner as the conventionally known treatment for introducing a phosphoric acid group using phosphoric acid-urea. Specifically, the cellulose nanocrystal and the phosphate group-containing compound are reacted at a temperature of 135 to 180 ° C. for 5 to 120 minutes in the presence of a urea-containing compound to form a phosphate group on the hydroxyl group of the cellulose glucose unit. Introduce.
  • Examples of the phosphoric acid group-containing compound include phosphoric acid, a lithium salt of phosphoric acid, a sodium salt of phosphoric acid, a potassium salt of phosphoric acid, and an ammonium salt of phosphoric acid. Among them, sodium dihydrogen phosphate, ammonium dihydrogen phosphate, phosphoric acid and the like can be preferably used alone or in combination.
  • the phosphoric acid group-containing compound is preferably added in an amount of 10 to 100 mmol with respect to 10 g (solid content) of cellulose nanocrystals.
  • Examples of the urea-containing compound include urea, thiourea, biuret, phenylurea, benzylurea, and dimethylurea. Among them, urea can be preferably used.
  • the urea-containing compound is preferably used in an amount of 150 to 200 mmol with respect to 10 g (solid content) of cellulose nanocrystals.
  • the hydrophilization treatment using a TEMPO catalyst (2,2,6,6-tetramethylpiperidin-1-oxyl) can be carried out in the same manner as a conventionally known oxidation method using a TEMPO catalyst.
  • cellulose nanocrystals having a sulfate group and / or a sulfo group are subjected to TEMPO catalyst (2,2,6,6-tetramethylpiperidine 1-oxyl) under aqueous conditions, normal temperature, and normal pressure.
  • the hydroxyl group at the 6-position of the cellulose glucose unit is oxidized to a carboxyl group to cause a hydrophilic reaction.
  • TEMPO catalyst in addition to the above 2,2,6,6-tetramethylpiperidin 1-oxyl, TEMPO derivatives such as 4-acetamido-TEMPO, 4-carboxy-TEMPO, and 4-phosphonoxy TEMPO can also be used.
  • the amount of the TEMPO catalyst used is 0.01 to 100 mmol, preferably 0.01 to 5 mmol, per 1 g of cellulose nanocrystals (solid content).
  • an oxidizing agent a bromide, an iodide or the like in combination with an oxidizing agent or a TEMPO catalyst.
  • the oxidizing agent include known oxidizing agents such as halogen, hypobromous acid, hypochlorous acid, perhalogen acid or salts thereof, halogen oxides, and peroxides, and in particular, sodium hypochlorite and the like. Sodium hypobromite can be preferably used.
  • the amount of the oxidizing agent is 0.5 to 500 mmol, preferably 5 to 50 mmol, per 1 g of the cellulose nanocrystal (solid content).
  • the additional oxidation treatment can be performed by further adding the oxidizing agent.
  • an alkali metal bromide such as sodium bromide and an alkali metal iodide such as sodium iodide can be preferably used.
  • the amount of the copolymerizer is 0.1 to 100 mmol, preferably 0.5 to 5 mmol, per 1 g of cellulose nanocrystals (solid content).
  • the reaction solution preferably uses water or an alcohol solvent as a reaction medium.
  • the reaction temperature of the hydrophilization treatment is in the range of 1 to 50 ° C., particularly 10 to 50 ° C., and may be room temperature.
  • the reaction time is preferably 1 to 360 minutes, particularly preferably 60 to 240 minutes.
  • a pH adjuster such as sodium hydroxide is used to adjust the pH to 9-12. It is desirable to keep it in the range.
  • a dispersion liquid may be prepared at the same time as defibration by using an ultra-high pressure homogenizer, a mixer, a grinder or the like as a miniaturization device and performing a defibration treatment using water or the like as a dispersion medium.
  • a disperser such as an ultrasonic disperser, a homogenizer, or a mixer can be preferably used, and a stirring method using a stirring rod, a stirring stone, or the like may be used.
  • the dispersion medium of the dispersion may be water alone, or may be a mixed solvent of water with an alcohol such as methanol, ethanol or isopropanol, a ketone such as 2-butanone or acetone, or an aromatic solvent such as toluene.
  • the cellulose nanocrystal dispersion liquid preferably contains cellulose nanocrystals (solid content) in the range of 0.1 to 90% by mass, and is aqueous dispersion having a solid content of 2% by mass and has a viscosity of 5.5. It has a zeta potential in the range of -50 to -55 mV at ⁇ 40 mPa ⁇ s (rotary viscometer, temperature 30 ° C., spindle rotation speed 100 rpm), and is excellent in handleability and coatability. Further, it is excellent in transparency with a visible light transmittance of 45% T or more with water dispersion having a solid content of 2% by mass.
  • the cellulose nanocrystal-containing coating liquid of the present invention can exhibit excellent gas barrier properties even under high humidity conditions by containing a water-soluble polymer and an inorganic layered compound together with the cellulose nanocrystal dispersion liquid. That is, the hydroxyl group-containing polymer can form a dense crosslinked structure together with the cellulose nanocrystals, and the gas barrier property of the obtained coating film is remarkably improved.
  • the layered inorganic compound has swelling property and openness, the cellulose nanocrystals enter and composite so as to widen the layers of the inorganic layered compound, and the permeation gas bypass effect obtained by the layered inorganic compound and the cellulose nanocrystals are obtained. Combined with the cross-linked structure of the above, it becomes possible to exhibit excellent gas barrier properties even under high humidity conditions.
  • water-soluble polymer examples of the water-soluble polymer contained in the coating liquid of the present invention include polyvinyl alcohol, vinyl acetate alcohol copolymer, ethylene vinyl alcohol copolymer, polyacrylic acid, polymethacrylic acid, carboxylmethylcellulose, starch and the like.
  • Polyvinyl alcohol can be preferably used.
  • Polyvinyl alcohol is preferably a fully saponified type and has a degree of polymerization of 100 to 10000.
  • the hydroxyl group-containing polymer is preferably blended in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content).
  • Inorganic layered compound As the inorganic layered compound, a naturally or synthetic compound, a conventionally known compound which exhibits hydrophilicity or hydrophobicity and exhibits swelling and cleavability with a solvent can be used, and is not limited to, but is limited to, kaolinite, chlorite, micalite, and the like. Examples of halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, hectrite, mica, tetrasilic mica, sodium teniolite, muscovite, margarite, talc, vermiculite, gold mica, zansophyllite, chlorite, etc. Therefore, synthetic mica (hydrophilic swelling property) can be preferably used.
  • the inorganic layered compound is preferably blended in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content).
  • a polyunsaturated carboxylic acid having good reaction efficiency is used as the reactive cross-linking agent.
  • the polyvalent carboxylic acid include alkyldicarboxylic acids such as citric acid, oxalic acid and malonic acid, aromatic dicarboxylic acids such as terephthalic acid and maleic acid, and anhydrides thereof, and in particular, citric acid anhydride.
  • the polyvalent carboxylic acid is preferably used.
  • the polyunsaturated carboxylic acid is preferably blended in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content).
  • the coating liquid of the present invention preferably contains an acid catalyst together with the cross-linking agent composed of the polyunsaturated carboxylic acid.
  • an acid catalyst include sulfuric acid, acetic acid, hydrochloric acid and the like, and sulfuric acid is particularly preferably used.
  • the acid catalyst is preferably blended in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass (solid content) of the cellulose nanocrystals.
  • known additives such as fillers, colorants, ultraviolet absorbers, antistatic agents, water resistant agents, metal salts, colloidal silica, alumina sol, titanium oxide, etc. are added to the cellulose nanocrystal-containing coating liquid, if necessary. Can be blended.
  • the molded product of the present invention is a molded product in which a layer containing the cellulose nanocrystals and the polyvalent cationic resin contained in the cellulose nanocrystal-containing coating liquid of the present invention is formed on a substrate, and the cellulose nano is formed.
  • the oxygen permeability at 23 ° C. and 50% RH is less than 3.8 (cc / m 2 ⁇ day ⁇ atm), and excellent oxygen barrier properties can be exhibited.
  • the adherence between the layer and the base material layer can be remarkably improved.
  • the base material particularly the base material made of a thermoplastic resin and the cellulose nano are made.
  • the interfacial peel strength of the crystal and the polyvalent cationic resin-containing layer is 2.3 (N / 15 mm) or more, and the occurrence of delamination is effectively prevented.
  • the molded product of the present invention by forming a layer made of the above-mentioned cellulose nanocrystal-containing coating liquid on a layer made of a multivalent cationic resin, a mixture capable of exhibiting excellent gas barrier properties and adhesion to a base material can be exhibited.
  • a layer with a state can be formed. That is, although it is difficult to quantitatively express the mixed state of the layer formed by the coating liquid and the polyvalent cationic resin of the present invention, the self-assembled structure of the cellulose nanocrystals described above is maintained. It is first formed by mixing a polyvalent cationic resin and cellulose nanocrystals.
  • the inside of the layer formed by the coating liquid of the present invention and the polyvalent cationic resin has a feature that cellulose nanocrystals and the polyvalent cationic resin are present from the vicinity of the outermost surface to the direction of the base material.
  • the polyvalent cationic resin used in the molded product of the present invention is a resin containing a water-soluble or water-dispersible polyvalent cationic functional group.
  • a polyvalent cationic resin include water-soluble amine polymers such as polyethyleneimine, polyallylamine, polyamine polyamide epichlorohydrin, and polyamine epichlorohydrin, polyacrylamide, poly (diallyldimethylammonium salt), dicyandiamideformalin, and poly.
  • Examples thereof include (meth) acrylate, cationized starch, cationized gum, gelatin, chitin, chitosan and the like, and among them, water-soluble amine polymers, particularly polyethyleneimine, can be preferably used.
  • base material examples include, but are not limited to, a base material made of a thermoplastic resin and a paper base material.
  • a base material made of thermoplastic resin a thermoplastic resin is used, and a film, sheet, bottle-shaped, cup-shaped, manufactured by means such as extrusion molding, injection molding, blow molding, stretch blow molding or press molding, etc.
  • tray-shaped and pouch-shaped molded bodies can be exemplified.
  • the thickness of the base material made of a thermoplastic resin cannot be unconditionally defined depending on the shape and application of the laminate, but in the case of a film, it is preferably in the range of 5 to 50 ⁇ m.
  • thermoplastic resin examples include low-, medium- or high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene-copolymer, ionomer, ethylene-vinyl acetate copolymer, and the like.
  • Olefin-based copolymers such as ethylene-vinyl alcohol copolymers; aromatic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate, and polyethylene naphthalate; fats such as polylactic acid, polycaprolactone, and polybutylene succinate.
  • polyesters such as nylon 6, nylon 6,6, nylon 6,10, metaxylylene adipamide; polystyrene, styrene-butadiene block copolymers, styrene-acrylonitrile copolymers, styrene-butadiene-acrylonitrile copolymers Styrene-based copolymers such as coalesced (ABS resin); vinyl chloride-based copolymers such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymers; acrylic-based copolymers such as polymethylmethacrylate and methylmethacrylate / ethylacrylate copolymers.
  • ABS resin coalesced
  • vinyl chloride-based copolymers such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymers
  • acrylic-based copolymers such as polymethylmethacrylate and methylmethacrylate / ethylacrylate copolymers.
  • thermoplastic resin examples thereof include copolymers; polycarbonate, cellulose-based resins; acetyl cellulose, cellulose acetyl propionate, cellulose acetate butyrate, and regenerated cellulose such as cellophane, but polyethylene terephthalate can be preferably used.
  • the thermoplastic resin may contain one or more additives such as pigments, antioxidants, antistatic agents, ultraviolet absorbers, and lubricants, if desired.
  • any paper can be used depending on the desired rigidity and the like.
  • Synthetic paper, clay coated paper, water resistant paper, acid resistant paper and other known papers can be used.
  • the thickness of the paper base material is preferably in the range of 150 to 400 ⁇ m or less, and the basis weight of the paper base material is preferably in the range of 150 to 350 g / m 2 .
  • Paper base materials include paper-making, sheet-shaped, cup-shaped, manufactured by means such as papermaking, coating molding, punching, slit molding, laminating molding, joining molding, seal molding, curling molding, and press molding. Examples thereof include tray-shaped, carton-shaped, pouch-shaped, and box-shaped molded bodies.
  • the laminated body including the molded product of the present invention other layers may be formed if necessary, in addition to the layer composed of the above-mentioned base material and the molded product.
  • the layer composed of a mixture of cellulose nanocrystals and polyvalent cation resin is suppressed from being deteriorated in gas barrier property under high humidity conditions, but conventional ones such as olefin resin, polyester resin, and curing reaction product of epoxy resin and polyamine resin are used. It is desirable to further form a layer made of a known moisture resistant resin.
  • the molded product of the present invention is a step of applying and drying a polyvalent cationic resin-containing solution on a base material to form a layer made of a polyvalent cationic resin, and the present invention is placed on the layer made of the polyvalent cationic resin.
  • a polyvalent cationic resin-containing solution on a base material to form a layer made of a polyvalent cationic resin
  • the present invention is placed on the layer made of the polyvalent cationic resin.
  • the polyvalent cationic resin-containing solution is preferably a solution containing the polyvalent cationic resin in an amount of 0.01 to 30% by mass, particularly 0.1 to 10% by mass based on the solid content.
  • the amount of the polyvalent cationic resin is smaller than the above range, the gas barrier property and the interfacial peel strength cannot be improved as compared with the case of the above range, while the polyvalent cationic resin is more than the above range. Even if the amount of the resin is large, the gas barrier property and the interfacial peeling strength cannot be further improved, which is inferior in economic efficiency and may be inferior in coatability and film forming property.
  • the solvent used for the polyvalent cationic resin-containing solution includes water, alcohols such as methanol, ethanol and isopropanol, ketones such as 2-butanone and acetone, aromatic solvents such as toluene, and mixed solvents of these and water. There may be.
  • the polyvalent cationic resin-containing solution contains, if necessary, fillers, colorants, ultraviolet absorbers, antistatic agents, water resistant agents, clay minerals, cross-linking agents, metal salts, colloidal silica, alumina sol, titanium oxide, etc. , Known additives can be blended.
  • the coating amount of the polyvalent cationic resin-containing solution is determined by the concentration of the polyvalent cationic resin-containing solution based on the amount of cellulose nanocrystals (solid content) in the layer formed from the cellulose nanocrystal-containing coating liquid. That is, as described above, when the cellulose nanocrystal (solid content) is contained in an amount of 1.0 g per 1 m 2 , the multivalent cationic resin is contained in an amount of 0.01 to 2.0 g per 1 m 2. It is preferable to apply the coating.
  • the amount of the polyvalent cationic resin is smaller than the above range, it is not possible to improve the interfacial peeling strength against a hydrophobic substrate such as a polyester resin as compared with the case where the amount is in the above range.
  • the amount of the polyvalent cationic resin is larger than the above range, the gas barrier property of the molded product may not be improved as compared with the case where the amount is in the above range.
  • the coating method is not limited to this, and for example, spray coating, dipping, or coating by a bar coater, a roll coater, a gravure coater, or the like can be used.
  • a method for drying the coating film it is preferable to dry the coating film at a temperature of 5 to 200 ° C. for 0.1 seconds to 24 hours.
  • the drying treatment can be performed by oven drying, infrared heating, high frequency heating, or the like, but may be natural drying.
  • the cellulose nanocrystal-containing coating liquid of the present invention described above is preferably coated so that the cellulose nanocrystals (solid content) are 0.1 to 3.0 g per 1 m 2.
  • the method for applying and drying the cellulose nanocrystal-containing coating solution can be the same as the method for applying and drying the polyvalent cation-containing solution, but at a temperature of 5 to 200 ° C. for 0.1 seconds to 24 hours. It is preferable to dry.
  • Amount of anionic functional group (mmol / g) Quantitative amount of sodium hydroxide droplets consumed for neutralization of anionic functional group (ml) ⁇ sodium hydroxide concentration (mmol / ml) ⁇ solid mass of nanocellulose (g) )
  • ⁇ Particle size distribution> Using a laser diffraction type particle size distribution measuring device (SALD-3100, Shimadzu Corporation), the average particle size, median diameter, and mode diameter were determined using an aqueous dispersion containing 2% by mass of cellulose nanocrystals.
  • the light source of the device is a semiconductor laser, and the wavelength is 690 nm.
  • the measurement results at an absorbance of 0.015 or less and a refractive index of 1.55 were used for the analysis.
  • Oxygen permeability measuring apparatus (OX-TRAN2 / 22, remote control) was used to measure the oxygen permeability of the shaped body (cc / m 2 ⁇ day ⁇ atm) under the conditions of 23 ° C. and humidity 50% RH.
  • Example 1 Cellulose nanocrystals were prepared by decomposing pulp with 64% by weight sulfuric acid. The cellulose nanocrystals are not dried and solidified, but are concentrated and washed in an ultracentrifuge to prepare cellulose nanocrystals that have been never dried, and finally the cellulose nanocrystals are ionized so that the solid content is 2% by mass. A cellulose nanocrystal dispersion was prepared by treating with an ultrasonic disperser for 10 minutes in addition to the exchanged water.
  • Example 2 A cellulose nanocrystal that has been never-dried in the same manner as in Example 1 is prepared, finally added to ion-exchanged water so that the cellulose nanocrystal has a solid content of 2% by mass, and treated with an ultra-high pressure homogenizer for 10 minutes. A cellulose nanocrystal dispersion was prepared.
  • Example 3 Never-dried cellulose nanocrystals were prepared in the same manner as in Example 1. To an aqueous dispersion containing 10 g (solid content) of cellulose nanocrystals, 0.8 mmol of TEMPO catalyst (manufactured by Sigma-Aldrich) and 12.1 mmol of sodium bromide were added, and ion-exchanged water was added to increase the volume to 1 L. Stirred until uniformly dispersed. Then, 5 mmol of sodium hypochlorite was added to start the oxidation reaction.
  • TEMPO catalyst manufactured by Sigma-Aldrich
  • the pH in the system was maintained from 10.0 to 10.5 with a 0.5 N aqueous sodium hydroxide solution, and the hydrophilization treatment was carried out with stirring at 30 ° C. for 4 hours.
  • the hydrophilized cellulose nanocrystals were washed with an ultracentrifugator (50,000 rpm, 10 minutes) while adding ion-exchanged water until the pH reached 8. Then, it was placed inside a dialysis membrane (manufactured by Spectrum Co., Ltd., molecular weight cut off of 3500 to 5000D) and allowed to stand in ion-exchanged water to remove impurities and the like to prepare cellulose nanocrystals.
  • the solid amount of cellulose nanocrystals oxidized by the TEMPO catalyst without solidifying the cellulose nanocrystals in the process can be obtained.
  • a 2% by mass cellulose nanocrystal dispersion was prepared.
  • Comparative Example 2 Cellulose nanocrystals dried and solidified were prepared in the same manner as in Comparative Example 1. The cellulose nanocrystals were oxidized with a TEMPO catalyst in the same manner as in Example 3 to prepare a cellulose nanocrystal dispersion having a solid content of 2% by mass of the cellulose nanocrystals.
  • ⁇ Pulse NMR> The cellulose nanocrystal dispersions obtained in Example 1 and Comparative Example 1 described above were concentrated to a solid content of 5% by mass, and free induction of the cellulose nanofiber dispersion at 30 ° C. measured by the solid echo method of pulse NMR. The decay (M (t)) was measured under the following conditions.
  • Measuring device Bruker TD-NMR the minispec mq20 Sample amount: Approximately 200 mg Observation nucleus: 1H Measurement: T2 Measurement method: Solid echo method 90 ° Pulse width: 2.2 ⁇ sec Number of integrations: 32 times Measurement temperature: 30 ° C (The device temperature was adjusted so that the sample internal temperature reached the measurement temperature 15 minutes after the device temperature reached the set temperature, and measurement was started). Repeat time: 8 sec
  • the proton ratio of the component ( ⁇ ) was 100 (%) and the T2 relaxation time of the component ( ⁇ ) was 1579 ( ⁇ sec), and the numerical analysis results of one component were obtained. ..
  • the proton ratio of the component ( ⁇ ) was 86.7 (%), the T2 relaxation time of the component ( ⁇ ) was 1519 ( ⁇ sec), and the proton ratio of the component ( ⁇ ) was 13.
  • the T2 relaxation time of 6 (%) and the component ( ⁇ ) was 7723 ( ⁇ sec), and the numerical analysis results of the two components of the component ( ⁇ ) and the component ( ⁇ ) were obtained. From this result, there are two components in the solvent, cellulose nanocrystals that have undergone dry solidification and cellulose nanocrystals that have been aggregated and dispersed, and the two components have non-uniform motility and are contained in the dispersion liquid. The inhomogeneity of cellulose nanocrystals can be seen.
  • Example 1 The cellulose nanocrystal dispersions obtained in Example 1 and Comparative Example 1 were concentrated to a solid content of 5% by mass, separated, frozen and broken at ⁇ 160 ° C., sublimated to ⁇ 80 ° C., and cooled. The fracture surface was adjusted by FIB and FE-SEM observation was performed while maintaining the state. SEM observation photographs are shown in FIGS. 2 and 3.
  • Example 4 ⁇ Preparation of cellulose nanocrystal-containing coating liquid> Using the cellulose nanocrystal dispersion of Example 1, dilute with ion-exchanged water so that the solid content of the cellulose nanocrystals is 1% by mass, anhydrous citric acid, sulfuric acid, synthetic mica (hydrophilic swelling mica, Katakura Corp.). Add 10 parts by mass, 2 parts by mass, 30 parts by mass and 30 parts by mass of cellulose nanocrystals (manufactured by Agri) and polyvinyl alcohol (completely saponified type, manufactured by Kuraray) to 100 parts by mass (solid content) of cellulose nanocrystals. Stirring was performed to prepare a cellulose nanocrystal-containing coating liquid having a pH of 3.
  • a molded product in which a layer containing a multivalent cationic resin and cellulose nanocrystals is formed was prepared by forming a layer containing a polyvalent cationic resin and cellulose nanocrystals by the following procedure.
  • Corona-treated biaxially stretched PET film Limira P60, 12 ⁇ m, manufactured by Toray Industries, Inc.
  • PEI Polyethylene imine
  • P-1000 manufactured by Nippon Catalyst Co., Ltd.
  • a hot air dryer MSO-TP, manufactured by ADVANTEC
  • a layer containing a polyvalent cation resin and cellulose nanocrystals is formed on a biaxially stretched PET film by coating with a coating amount of 1.0 g / m 2 and air-drying at room temperature overnight.
  • a molded product was prepared.
  • Example 5 A cellulose nanocrystal-containing coating liquid was prepared in the same manner as in Example 4 except that the cellulose nanocrystal dispersion liquid of Example 2 was used, and then a layer containing a polyvalent cationic resin and a cellulose nanocrystal was formed. A molded product was prepared.
  • Example 3 A cellulose nanocrystal-containing coating liquid was prepared in the same manner as in Example 4 except that the cellulose nanocrystal dispersion liquid of Comparative Example 1 was used, and then a layer containing a polyvalent cationic resin and a cellulose nanocrystal was formed. A molded product was prepared.
  • the cellulose nanocrystal dispersion liquid of the present invention is excellent in coatability and handleability, can form a coating film having excellent gas barrier property and transparency, and is used as a coating agent capable of imparting gas barrier performance. .. In addition, it has better dispersibility than the dispersion liquid in which solidified cellulose nanocrystals are dispersed, and by forming a molded product composed of a mixture of a polyvalent cationic resin and a cross-linking agent, it can be used as a gas barrier film or thermoplastic. Since the interfacial peeling strength with a hydrophobic base material made of resin or the like is also improved, it is suitably used as a gas barrier laminate.

Abstract

The present invention relates to a dispersion liquid of cellulose nanocrystals containing a sulfate group and/or a sulfo group derived by sulfuric acid treatment and an anionic functional group derived by hydrophilization treatment, the cellulose nanocrystal dispersion liquid being excellent in cellulose nanocrystal dispersibility and having excellent transparency with visible light transmittance of 45%T or more at 600 nm in an aqueous dispersion having a solid content of 2% by mass. A coating liquid containing this cellulose nanocrystal dispersion liquid can exhibit excellent barrier properties and handleability and is also excellent in productivity and economic efficiency.

Description

セルロースナノクリスタル分散液及びセルロースナノクリスタル含有コーティング液Cellulose nanocrystal dispersion liquid and cellulose nanocrystal-containing coating liquid
　本発明は、セルロースナノクリスタル分散液及びセルロースナノクリスタル含有コーティング液に関するものであり、より詳細には、分散性及び塗工性に優れ、透明性及びガスバリア性に優れた塗膜を形成可能なセルロースナノクリスタル分散液及びセルロースナノクリスタル含有コーティング液に関する。 The present invention relates to a cellulose nanocrystal dispersion liquid and a cellulose nanocrystal-containing coating liquid, and more specifically, cellulose capable of forming a coating film having excellent dispersibility and coatability, and excellent transparency and gas barrier property. The present invention relates to a nanocrystal dispersion liquid and a cellulose nanocrystal-containing coating liquid.
　ナノセルロースは、高度バイオマス原料として、機能性添加剤、フィルム複合材料等として種々な用途に使用することが提案されている。特に、セルロースナノファイバー（ＣＮＦ）から成る膜やセルロースナノファイバーを含有する積層体等の材料は、セルロース繊維間の水素結合や架橋的な強い相互作用から、ガスの溶解、拡散を抑制できるため酸素バリア性等のガスバリア性に優れていることが知られており、セルロースナノファイバーを利用したバリア材料が提案されている。
　セルロース繊維の微細化のため、機械的処理と共に、カルボキシル基やリン酸基等の親水性の官能基を、セルロースの水酸基に導入する化学的処理を行うことが行われており、これにより微細化処理に要するエネルギーを低減可能であると共に、バリア性や水系溶媒への分散性が向上する。 It has been proposed that nanocellulose is used as an advanced biomass raw material, as a functional additive, as a film composite material, and for various purposes. In particular, materials such as a film made of cellulose nanofibers (CNF) and a laminate containing cellulose nanofibers can suppress the dissolution and diffusion of gas due to hydrogen bonds between cellulose fibers and strong cross-linking interactions, so that oxygen can be suppressed. It is known to have excellent gas barrier properties such as barrier properties, and barrier materials using cellulose nanofibers have been proposed.
In order to make the cellulose fibers finer, a chemical treatment is carried out in which hydrophilic functional groups such as a carboxyl group and a phosphoric acid group are introduced into the hydroxyl groups of the cellulose in addition to the mechanical treatment. The energy required for the treatment can be reduced, and the barrier property and the dispersibility in an aqueous solvent are improved.
　このようなセルロースナノファイバーを用いた分散液も知られており、例えば、下記特許文献１には、結晶化度が７０％以上、銅エチレンジアミン溶液を用いた粘度法による重合度が１６０以下、且つ繊維径が５０ｎｍ以下であるセルロースナノファイバーが分散媒に分散している分散液が提案されている。
　また下記特許文献２には、数平均繊維長２５０ｎｍ以下、かつ数平均繊維径２～５ｎｍのセルロースナノファイバーが分散媒に分散している分散液が提案されている。 A dispersion liquid using such cellulose nanofibers is also known. For example, in Patent Document 1 below, the crystallinity is 70% or more, the degree of polymerization by the viscosity method using a copper ethylenediamine solution is 160 or less, and the degree of polymerization is 160 or less. A dispersion liquid in which cellulose nanofibers having a fiber diameter of 50 nm or less are dispersed in a dispersion medium has been proposed.
Further, Patent Document 2 below proposes a dispersion liquid in which cellulose nanofibers having a number average fiber length of 250 nm or less and a number average fiber diameter of 2 to 5 nm are dispersed in a dispersion medium.
特開２０１３－２５６５４６号公報Japanese Unexamined Patent Publication No. 2013-256546 国際公開２０１４／０６１４８５International release 2014/061485
　しかしながら、上記特許文献１に記載されたセルロースナノファイバー分散液においては、分散媒に分散させるセルロースナノファイバーを調製する工程として、ＴＥＭＰＯ触媒を用いて化学処理されたセルロースナノファイバーを低粘度化する工程や、或いはナノファイバー化させる微粒化工程が必要であり、生産性や経済性の点で十分満足するものではない。またセルロースナノファイバーは繊維長が長いことからガスバリア性の点で満足するものではなく、繊維長を短くすれば高いガスバリア性を得ることも可能であるが、そのためには更なる処理が必要であり、経済性に劣る。
　また上記特許文献２では、分散液の分散性を向上するために低粘度化が可能な繊維長の短いセルロースナノファイバーを調製しているが、繊維長の短いセルロースナノファイバーを調製するために特別な原料を使用する必要があり、やはり生産性や経済性に劣る。 However, in the cellulose nanofiber dispersion liquid described in Patent Document 1, as a step of preparing the cellulose nanofibers to be dispersed in the dispersion medium, a step of reducing the viscosity of the cellulose nanofibers chemically treated using a TEMPO catalyst. Or, a micronization step for making nanofibers is required, and the productivity and economic efficiency are not sufficiently satisfied. In addition, cellulose nanofibers are not satisfactory in terms of gas barrier properties due to their long fiber length, and it is possible to obtain high gas barrier properties by shortening the fiber length, but further treatment is required for that purpose. , Inferior in economy.
Further, in Patent Document 2 above, cellulose nanofibers having a short fiber length capable of lowering the viscosity are prepared in order to improve the dispersibility of the dispersion liquid, but specially for preparing cellulose nanofibers having a short fiber length. It is necessary to use various raw materials, which is also inferior in productivity and economy.
　セルロースナノファイバーに比して繊維長の短いナノセルロースとして、セルロース繊維を強酸で加水分解処理して成るセルロースナノクリスタル（ＣＮＣ）が知られている。セルロースナノクリスタルは繊維長が短いことから、塗工時の取扱い性に優れていると共に、塗工面の平滑性にも優れている。しかしながら、一般にセルロースナノクリスタルは、上述したようなカルボキシル基等が導入されたセルロースナノファイバーに比してガスバリア性に劣っている。
　本発明者等は、セルロースナノクリスタルがアニオン性官能基を多く含有することにより、優れたガスバリア性を発現できることを見出した（特願２０１８－１７７６１０）。
　しかしながら、かかるセルロースナノクリスタルは、保存性や搬送性等の観点から一般にパウダー状に固形化されており、分散液を得るには、パウダー化されたセルロースナノクリスタルを分散媒に凝集を抑制しながら分散させることが必要であり、やはり生産性や経済性の点で満足するものではない。また本発明者等の研究により、このような固形化（パウダー状）されたセルロースナノクリスタルを分散させた分散液は、アニオン性官能基を含有するセルロースナノクリスタルのガスバリア性を低下させてしまうことが分かった。 As nanocellulose having a shorter fiber length than cellulose nanofibers, cellulose nanocrystals (CNC) formed by hydrolyzing cellulose fibers with a strong acid are known. Since cellulose nanocrystals have a short fiber length, they are excellent in handleability at the time of coating and also excellent in smoothness of the coated surface. However, in general, cellulose nanocrystals are inferior in gas barrier properties to cellulose nanofibers into which a carboxyl group or the like has been introduced as described above.
The present inventors have found that cellulose nanocrystals can exhibit excellent gas barrier properties by containing a large amount of anionic functional groups (Japanese Patent Application No. 2018-177610).
However, such cellulose nanocrystals are generally solidified in the form of powder from the viewpoint of storage stability, transportability, etc., and in order to obtain a dispersion liquid, powdered cellulose nanocrystals are used as a dispersion medium while suppressing aggregation. It needs to be dispersed, and it is not satisfactory in terms of productivity and economy. Further, according to the research by the present inventors, the dispersion liquid in which such solidified (powder-like) cellulose nanocrystals are dispersed reduces the gas barrier property of the cellulose nanocrystals containing anionic functional groups. I understood.
　従って本発明の目的は、セルロースナノクリスタルの分散性に優れ、優れたバリア性及び取扱い性を発現可能であると共に、生産性及び経済性にも優れたセルロースナノクリスタル分散液を提供することである。
　本発明の他の目的は、ガスバリア性及び取扱い性に優れたセルロースナノクリスタル分散液を使用し、セルロースナノクリスタルが均一に分散された架橋構造を効率よく形成可能なセルロースナノクリスタル含有コーティング液を提供することである。
　本発明の更に他の目的は、優れたガスバリア性及び層間接着性を有するセルロースナノクリスタル含有層を有する成形体を提供することである。 Therefore, an object of the present invention is to provide a cellulose nanocrystal dispersion liquid which is excellent in dispersibility of cellulose nanocrystals, can exhibit excellent barrier properties and handleability, and is also excellent in productivity and economy. ..
Another object of the present invention is to provide a cellulose nanocrystal-containing coating liquid capable of efficiently forming a crosslinked structure in which cellulose nanocrystals are uniformly dispersed by using a cellulose nanocrystal dispersion liquid having excellent gas barrier properties and handleability. It is to be.
Still another object of the present invention is to provide a molded product having a cellulose nanocrystal-containing layer having excellent gas barrier properties and interlayer adhesiveness.
　本発明によれば、硫酸処理由来の硫酸基及び／又はスルホ基、及び親水化処理由来のアニオン性官能基を含有するセルロースナノクリスタル分散液であって、前記セルロースナノクリスタルの固形分量が２質量％の水分散の６００ｎｍの可視光線透過率が４５％Ｔ以上であることを特徴とするセルロースナノクリスタル分散液が提供される。 According to the present invention, a cellulose nanocrystal dispersion containing a sulfate group and / or a sulfo group derived from a sulfuric acid treatment and an anionic functional group derived from a hydrophilic treatment, wherein the solid content of the cellulose nanocrystals is 2% by mass. Provided is a cellulose nanocrystal dispersion liquid characterized by having a visible light transmittance at 600 nm of% aqueous dispersion of 45% T or more.
　本発明のセルロースナノクリスタル分散液においては、
　１．前記セルロースナノクリスタル分散液のレーザ回折式粒度分布測定装置によるセルロースナノクリスタルの平均粒径が１０．１μｍ以下且つメディアン径が１０．６μｍ以下且つモード径が１０．９μｍ以下であること、
　２．前記硫酸基及び／又はスルホ基、及びアニオン性官能基の総量が０．１７ｍｍｏｌ／ｇより多く且つ４．０ｍｍｏｌ／ｇ以下であること、
　３．前記セルロースナノクリスタルの結晶化度が６０％以上であり、且つ繊維径が５０ｎｍ以下でアスペクト比が５～５０であること、
　４．前記アニオン性官能基が、硫酸基、スルホ基、リン酸基、カルボキシル基のうちの少なくとも１つであること、
　５．前記親水化処理が、ネバードライ処理、又はネバードライ処理と、カルボジイミド、硫酸、三酸化硫黄－ピリジン錯体、リン酸－尿素、ＴＥＭＰＯ触媒、酸化剤の何れかを用いた処理との組み合わせであること、
が好適である。 In the cellulose nanocrystal dispersion of the present invention,
1. 1. The average particle size of the cellulose nanocrystals by the laser diffraction type particle size distribution measuring device of the cellulose nanocrystal dispersion is 10.1 μm or less, the median diameter is 10.6 μm or less, and the mode diameter is 10.9 μm or less.
2. The total amount of the sulfate group and / or the sulfo group and the anionic functional group is more than 0.17 mmol / g and 4.0 mmol / g or less.
3. 3. The degree of crystallinity of the cellulose nanocrystal is 60% or more, the fiber diameter is 50 nm or less, and the aspect ratio is 5 to 50.
4. The anionic functional group is at least one of a sulfuric acid group, a sulfo group, a phosphoric acid group, and a carboxyl group.
5. The hydrophilization treatment is a combination of a never dry treatment or a never dry treatment and a treatment using any one of carbodiimide, sulfuric acid, sulfur trioxide-pyridine complex, phosphoric acid-urea, TEMPO catalyst, and oxidizing agent. ,
Is preferable.
　本発明によればまた、上記セルロースナノクリスタル分散液、水溶性高分子、無機層状化合物及び多価カルボン酸を含有することを特徴とするセルロースナノクリスタル含有コーティング液が提供される。
　本発明のセルロースナノクリスタル含有コーティング液においては、
　１．前記水溶性高分子がポリビニルアルコールであり、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で含有すること、
　２．前記無機層状化合物がマイカであり、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で含有すること、
　３．前記多価カルボン酸がクエン酸であり、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で含有すること、
が好適である。 According to the present invention, there is also provided a cellulose nanocrystal-containing coating liquid containing the above-mentioned cellulose nanocrystal dispersion liquid, a water-soluble polymer, an inorganic layered compound and a polyvalent carboxylic acid.
In the cellulose nanocrystal-containing coating liquid of the present invention,
1. 1. The water-soluble polymer is polyvinyl alcohol, which is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of cellulose nanocrystals (solid content).
2. The inorganic layered compound is mica and is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of cellulose nanocrystals (solid content).
3. 3. The polyunsaturated carboxylic acid is citric acid, which is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of cellulose nanocrystals (solid content).
Is preferable.
　本発明によれば更に、基材上に、多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体であって、前記セルロースナノクリスタル（固形分）を１．０ｇ／ｍ２の量で含有するときの酸素透過度（２３℃５０％ＲＨ）が３．８ｃｃ／ｍ２・ｄａｙ・ａｔｍ未満であることを特徴とする成形体が提供される。 According to the present invention, the molded product is further formed by forming a layer containing a polyvalent cationic resin and a cellulose nanocrystal on a base material, and the cellulose nanocrystal (solid content) is 1.0 g / m 2 of the above. Provided is a molded article having an oxygen permeability (23 ° C., 50% RH) of less than 3.8 cc / m 2, day, atm when contained in an amount of.
　本発明のセルロースナノクリスタル分散液においては、繊維長が短く且つ繊維径の小さいセルロースナノクリスタルが、凝集することなく均一に分散されているため、塗工性及び取扱い性に優れていると共に、透明性にも優れており、セルロースナノクリスタルの固形分量が２質量％の水分散における可視光線透過率が４５％Ｔ以上と優れた透明性を有している。
　また本発明において、セルロースナノクリスタルは硫酸処理由来の硫酸基及び／又はスルホ基、及び親水化処理由来のアニオン性官能基を有しており、セルロースナノクリスタル間の荷電反発による緻密な自己組織化構造が形成されていることから、優れたガスバリア性を発現できる。また繊維長の短いセルロースナノクリスタルから成り、これらが分散液中に均一に分散していることにより、上述した自己組織化構造と相まって、ガスバリア性がより向上されている。
　本発明のセルロースナノクリスタル分散液は、後述する実施例の結果から明らかなように、固形化されたセルロースナノクリスタルを同一固形分量として分散させた分散液に比して、透明性（可視光線透過率）やガスバリア性に優れている。また固形化されたセルロースナノクリスタルを再分散させて分散液を調製する必要もなく、経済性や取扱い性の点でも優れている。
　また本発明においては、セルロースナノクリスタルが、乾燥固化を経ることのないネバードライ処理されたものであることが特に好適であり、これによりセルロースナノクリスタルが微細且つ均質な分散状態にある分散液とすることができる。 In the cellulose nanocrystal dispersion liquid of the present invention, the cellulose nanocrystals having a short fiber length and a small fiber diameter are uniformly dispersed without agglomeration, so that they are excellent in coatability and handleability and are transparent. It is also excellent in properties, and has excellent transparency with a visible light transmittance of 45% T or more in an aqueous dispersion in which the solid content of the cellulose nanocrystal is 2% by mass.
Further, in the present invention, the cellulose nanocrystals have a sulfuric acid group and / or a sulfo group derived from the sulfuric acid treatment and an anionic functional group derived from the hydrophilic treatment, and are densely self-assembled by charge repulsion between the cellulose nanocrystals. Since the structure is formed, excellent gas barrier properties can be exhibited. Further, since it is composed of cellulose nanocrystals having a short fiber length and these are uniformly dispersed in the dispersion liquid, the gas barrier property is further improved in combination with the above-mentioned self-assembled structure.
As is clear from the results of Examples described later, the cellulose nanocrystal dispersion liquid of the present invention is more transparent (visible light transmission) than the dispersion liquid in which solidified cellulose nanocrystals are dispersed as the same solid content. Excellent rate) and gas barrier properties. Further, it is not necessary to redisperse the solidified cellulose nanocrystals to prepare a dispersion liquid, which is excellent in terms of economy and handleability.
Further, in the present invention, it is particularly preferable that the cellulose nanocrystals are never-dried without undergoing drying and solidification, whereby the cellulose nanocrystals can be used as a dispersion liquid in a fine and homogeneous dispersed state. can do.
　本発明のセルロースナノクリスタル含有コーティング液においては、上述したセルロースナノクリスタル分散液を使用することにより、生産性及び経済性良く、ガスバリア性に優れた塗膜を形成可能なコーティング液を調製することができる。
　また上述した通り、繊維長が短いセルロースナノクリスタルが凝集することなく、均一に分散した分散液を使用していることから、塗工時のハンドリング性に優れ、塗工表面の平滑性にも優れている。また、得られる塗膜はガスバリア性にも優れている。
　本発明のセルロースナノクリスタル含有コーティング液においては、セルロースナノクリスタルの水酸基と多価カルボン酸が緻密な架橋膜を構成することによる優れたガスバリア性と、水溶性高分子及び無機層状化合物が含有されていることに基づくガスバリア性の向上とが相俟って、高湿度条件下においても優れたガスバリア性を発現することが可能になる。
　更に、本発明の多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体においては、セルロースナノクリスタル間の緻密な自己組織化構造を維持しながら、セルロースナノクリスタル間に多価カチオン樹脂が自然拡散して介在した混合状態になっており、ナノセルロースの自己組織化構造が多価カチオンによって更に強化されていることから、ナノセルロースだけで発現されるガスバリア性よりも優れたガスバリア性を有する。 In the cellulose nanocrystal-containing coating liquid of the present invention, by using the above-mentioned cellulose nanocrystal dispersion liquid, it is possible to prepare a coating liquid capable of forming a coating film having good productivity and economy and excellent gas barrier property. it can.
Further, as described above, since the cellulose nanocrystals having a short fiber length are not aggregated and the dispersion liquid is uniformly dispersed, the handling property at the time of coating is excellent and the smoothness of the coating surface is also excellent. ing. In addition, the obtained coating film has excellent gas barrier properties.
The cellulose nanocrystal-containing coating liquid of the present invention contains excellent gas barrier properties due to the hydroxyl group of the cellulose nanocrystal and the polyvalent carboxylic acid forming a dense crosslinked film, and contains a water-soluble polymer and an inorganic layered compound. Combined with the improvement of gas barrier property based on the presence, it becomes possible to exhibit excellent gas barrier property even under high humidity conditions.
Further, in the molded product in which the layer containing the polyvalent cationic resin and the cellulose nanocrystals of the present invention is formed, the polyvalent value between the cellulose nanocrystals is maintained while maintaining the dense self-assembled structure between the cellulose nanocrystals. Since the cation resin is naturally diffused and intervened in a mixed state, and the self-assembled structure of nanocellulose is further strengthened by the polyvalent cation, the gas barrier is superior to the gas barrier property expressed only by nanocellulose. Has sex.
粒子径の計算方法を説明するための図である。It is a figure for demonstrating the calculation method of a particle diameter. 実施例１の分散液中のセルロースナノクリスタルの分散状態を示すクライオＳＥＭ写真であり、（Ａ）は実際大きさの５０００倍写真であり、（Ｂ）は（Ａ）のＸ部分の拡大写真（実際の大きさの２００００倍）、（Ｃ）は（Ａ）のＹ部分の拡大写真（実際の大きさの２００００倍）、（Ｄ）は（Ｂ）のＺ部分の拡大写真（実際の大きさの１０００００倍）、（Ｅ）は（Ｃ）のＺ部分の拡大写真（実際の大きさの１０００００倍）である。It is a cryo-SEM photograph which shows the dispersion state of the cellulose nanocrystal in the dispersion liquid of Example 1, (A) is the photograph which is 5000 times the actual size, and (B) is the enlarged photograph of the X part of (A) (A). (20,000 times the actual size), (C) is an enlarged photograph of the Y part of (A) (20,000 times the actual size), (D) is an enlarged photograph of the Z part of (B) (actual size) (100,000 times), (E) is an enlarged photograph (100,000 times the actual size) of the Z portion of (C). 比較例１の分散液中のセルロースナノクリスタルの分散状態を示すクライオＳＥＭ写真であり、（Ａ）は実際大きさの５０００倍写真であり、（Ｂ）は（Ａ）のＸ部分の拡大写真（実際の大きさの２００００倍）、（Ｃ）は（Ａ）のＹ部分の拡大写真（実際の大きさの２００００倍）、（Ｄ）は（Ｂ）のＺ部分の拡大写真（実際の大きさの１０００００倍）、（Ｅ）は（Ｃ）のＺ部分の拡大写真（実際の大きさの１０００００倍）である。It is a cryo-SEM photograph showing the dispersion state of the cellulose nanocrystal in the dispersion liquid of Comparative Example 1, (A) is a photograph which is 5000 times the actual size, and (B) is an enlarged photograph of the X part of (A) (A). (20,000 times the actual size), (C) is an enlarged photograph of the Y part of (A) (20,000 times the actual size), (D) is an enlarged photograph of the Z part of (B) (actual size) (100,000 times), (E) is an enlarged photograph (100,000 times the actual size) of the Z portion of (C).
　本発明のセルロースナノクリスタル分散液は、硫酸処理由来の硫酸基及び／又はスルホ基、及び親水化処理由来のアニオン性官能基を含有するセルロールナノクリスタルが分散媒中に凝集することなく、均一に分散して成る分散液であることから、セルロースナノクリスタルの固形分量が２質量％の水分散の可視光線透過率が４５％Ｔ以上と、優れた透明性を有している。
　また、セルロースナノクリスタルによるガスバリア性は、セルロースナノクリスタル同士の荷電反発により形成される自己組織化構造が透過ガスの透過経路の障壁になることにより発現されるが、本発明のセルロースナノクリスタル分散液においては、セルロースナノクリスタルの表面に硫酸基及び／又はスルホ基やカルボキシル基等のアニオン性官能基が存在することにより、これらのアニオン性官能基が有する電荷（アニオン）により自己組織化構造を効率よく形成し、上述した均一分散性と相俟って優れたガスバリア性を発現できる。 In the cellulose nanocrystal dispersion of the present invention, cellol nanocrystals containing a sulfate group and / or a sulfo group derived from a sulfuric acid treatment and an anionic functional group derived from a hydrophilization treatment are uniform without agglomeration in the dispersion medium. Since it is a dispersion liquid dispersed in, it has excellent transparency with a visible light transmittance of 45% T or more in an aqueous dispersion having a solid content of 2% by mass of cellulose nanocrystals.
Further, the gas barrier property of the cellulose nanocrystals is expressed by the self-assembled structure formed by the charge repulsion between the cellulose nanocrystals acting as a barrier of the permeation path of the permeated gas. In the case, since anionic functional groups such as sulfate group and / or sulfo group and carboxyl group are present on the surface of the cellulose nanocrystal, the self-assembled structure is made efficient by the charge (anion) possessed by these anionic functional groups. It is well formed and can exhibit excellent gas barrier properties in combination with the above-mentioned uniform dispersibility.
　更に本発明のセルロースナノクリスタル分散液においては、レーザ回折式粒度分布測定装置によるセルロースナノクリスタルの平均粒径が１０．１μｍ以下且つメディアン径が１０．６μｍ以下且つモード径が１０．９μｍ以下であることが好適である。
　粒度分布とは、測定対象となる分散液のサンプル粒子群の中に、どのような大きさ（粒子径）の粒子が、どのような割合（全体を１００％とする相対粒子量）で含まれているかを示す指標である。レーザ回折式粒度分布装置によってレーザ回折・散乱法での光強度分布データパターンから粒子径を特定し、計算によって体積基準の粒度分布を求める。また体積基準の粒度分布に基づいて個数基準の粒度分布を計算することもできる。
　レーザ回折式粒度分布測定装置は、測定対象となる粒子群にレーザ光を照射すると、空間的に回折・散乱光の光強度分布パターンが生じ、このうち前方散乱光の光強度分布パターンは、レンズによって集光され、焦点距離の位置にある検出面に、リング状の回折・散乱像を結ぶ。これを同心円状に検出素子を配置したリングセンサで検出する。また、側方散乱光および後方散乱光は、側方散乱光センサおよび後方散乱光センサでそれぞれ検出する。このように各種検出素子を用いて光強度分布パターンを検出し、光強度分布データを得る。
　分散液中のセルロースナノクリスタルが希薄な濃度で存在する状態において、レーザ回折式粒度分布装置の測定結果を解析することにより、セルロースナノクリスタルの平均粒径およびメディアン径およびモード径を求めることができる。分散液中のセルロースナノクリスタルの平均粒径及びメディアン径及びモード径が上記範囲にある分散液においては、分散性が良く、ガスバリア性及び塗工時のハンドリング性に優れていると共に、塗工表面の平滑性に優れるという利点もある。 Further, in the cellulose nanocrystal dispersion liquid of the present invention, the average particle size of the cellulose nanocrystals by the laser diffraction type particle size distribution measuring device is 10.1 μm or less, the median diameter is 10.6 μm or less, and the mode diameter is 10.9 μm or less. Is preferable.
The particle size distribution means that particles of what size (particle size) are included in the sample particle group of the dispersion liquid to be measured, and at what ratio (relative particle amount with the whole as 100%). It is an index showing whether or not it is. The particle size is specified from the light intensity distribution data pattern by the laser diffraction / scattering method using a laser diffraction type particle size distribution device, and the volume-based particle size distribution is obtained by calculation. It is also possible to calculate the number-based particle size distribution based on the volume-based particle size distribution.
In the laser diffraction type particle size distribution measuring device, when the particle group to be measured is irradiated with laser light, a light intensity distribution pattern of diffracted / scattered light is spatially generated, and the light intensity distribution pattern of the forward scattered light is a lens. A ring-shaped diffracted / scattered image is formed on the detection surface at the focal distance. This is detected by a ring sensor in which detection elements are arranged concentrically. Further, the side scattered light and the backscattered light are detected by the side scattered light sensor and the backscattered light sensor, respectively. In this way, the light intensity distribution pattern is detected using various detection elements, and the light intensity distribution data is obtained.
The average particle size, median diameter, and mode diameter of the cellulose nanocrystals can be obtained by analyzing the measurement results of the laser diffraction type particle size distribution device in a state where the cellulose nanocrystals in the dispersion liquid are present at a dilute concentration. .. In a dispersion in which the average particle size, median diameter, and mode diameter of the cellulose nanocrystals in the dispersion are in the above ranges, the dispersibility is good, the gas barrier property and the handling property at the time of coating are excellent, and the coating surface is excellent. It also has the advantage of being excellent in smoothness.
　粒度分布は、通常、粒子径スケールに対する粒子量（積算または頻度）として表現される。また、レーザ回折式粒度分布測定装置の測定原理であるレーザ回折・散乱法では、粒子が球形であると仮定して計算された回折・散乱光の光強度分布パターンに基づいて粒度分布を求められる。したがって、粒度分布測定では、常に粒子が球形であるという前提や仮定に基づいて測定が行われる。
　セルロースナノクリスタルのような繊維状粒子の場合、得られる粒度分布は、繊維状粒子の短径が分布下限に、長径が分布上限にほぼ相当するような比較的広い分布が得られる。これは、セル内部では、繊維状粒子の方向がランダムであると考えられること、また、ある程度粒子の方向が一定であったとしても、回折・散乱光を検出するセンサの形状が１／４円となっているため、結果的に一定方向のみの回折・散乱光を検出することにはならないからである。
　さまざまな形状・サイズの繊維状粒子が含まれている場合、測定結果の分布範囲は、その中で最も小さな短径から、最も大きな長径へと広がり、繊維状粒子の場合でも、測定対象の粒子群に含まれる粒子の形状・サイズのばらつきが大きくなれば分布範囲は広がり、ばらつきが小さくなれば分布範囲は狭くなり、形状やサイズが大きくなれば、粒度分布は全体として大きいほうに移動し、形状・サイズが小さくなれば、粒度分布は全体として小さいほうに移動する。繊維状粒子が凝集していれば、粒度分布は全体として大きいほうに移動し、分散していれば、粒度分布は全体として小さいほうに移動する。このように、レーザ回折式粒度分布測定装置によってセルロースナノクリスタルの繊維特性を定量的に評価できる。 The particle size distribution is usually expressed as a particle size (integration or frequency) relative to the particle size scale. Further, in the laser diffraction / scattering method, which is the measurement principle of the laser diffraction type particle size distribution measuring device, the particle size distribution can be obtained based on the light intensity distribution pattern of the diffraction / scattered light calculated on the assumption that the particles are spherical. .. Therefore, the particle size distribution measurement is always based on the assumption or assumption that the particles are spherical.
In the case of fibrous particles such as cellulose nanocrystals, the obtained particle size distribution is such that the minor axis of the fibrous particles corresponds to the lower limit of the distribution and the major axis substantially corresponds to the upper limit of the distribution. This is because it is considered that the directions of the fibrous particles are random inside the cell, and even if the directions of the particles are constant to some extent, the shape of the sensor that detects diffracted / scattered light is 1/4 yen. As a result, it is not possible to detect diffracted / scattered light only in a certain direction.
When fibrous particles of various shapes and sizes are included, the distribution range of the measurement result extends from the smallest minor axis to the largest major axis, and even in the case of fibrous particles, the particles to be measured. The larger the variation in the shape and size of the particles contained in the group, the wider the distribution range, the smaller the variation, the narrower the distribution range, and the larger the shape and size, the larger the particle size distribution as a whole. As the shape and size become smaller, the particle size distribution shifts to the smaller one as a whole. If the fibrous particles are agglomerated, the particle size distribution moves to the larger side as a whole, and if they are dispersed, the particle size distribution moves to the smaller side as a whole. In this way, the fiber characteristics of the cellulose nanocrystals can be quantitatively evaluated by the laser diffraction type particle size distribution measuring device.
　平均粒径については対数スケールに基いて計算し、各粒子径の値に相対粒子量（差分％）を掛けて、相対粒子量の合計（１００％）で割ることによって計算する。具体的には、まず測定対象となる粒子径範囲（最大粒子径：ｘ１、最小粒子径：ｘｎ＋１）をｎ分割し、それぞれの粒子径区間を、［ｘｊ、ｘｊ＋１］（ｊ＝１，２，・・・・ｎ）とする。この場合の分割は対数スケール上での等分割となる。また、対数スケールに基いてそれぞれの粒子径区間での代表粒子径は下記式（１） The average particle size is calculated based on the logarithmic scale, and the value of each particle size is multiplied by the relative particle amount (difference%) and divided by the total relative particle amount (100%). Specifically, first, the particle size range (maximum particle size: x1, minimum particle size: xn + 1) to be measured is divided into n, and each particle size section is divided into [xj, xj + 1] (j = 1, 2, 2,・ ・ ・ ・ N). The division in this case is an equal division on a logarithmic scale. Further, based on the logarithmic scale, the representative particle size in each particle size section is given by the following equation (1).
Figure JPOXMLDOC01-appb-M000001
 で計算する。
　この代表粒子径は対数により表されていることからこの時点で粒子径の単位ではなくなる。さらにｑｊ（ｊ＝１，２，・・・・ｎ）を、粒子径区間［ｘｊ、ｘｊ＋１］に対応する相対粒子量（差分％）とし、全区間の合計を１００％とすると、対数スケール上での平均値μは下記式（２）
Figure JPOXMLDOC01-appb-M000001
 Calculate with.
Since this representative particle size is represented by a logarithm, it is no longer a unit of particle size at this point. Further, assuming that qj (j = 1, 2, ... n) is the relative particle amount (difference%) corresponding to the particle size interval [xj, xj + 1] and the total of all the intervals is 100%, it is on the logarithmic scale. The average value μ in is calculated by the following equation (2).
Figure JPOXMLDOC01-appb-M000002
 で計算できる。
　このμは、対数スケール上の数値であり、粒子径としての単位を持たないので、粒子径の単位に戻すために１０μすなわち１０のμ乗を計算している。この１０μが平均粒子径となる。
Figure JPOXMLDOC01-appb-M000002
 Can be calculated with.
Since this μ is a numerical value on a logarithmic scale and does not have a unit as a particle size, 10 μ, that is, 10 μ power is calculated in order to return to the unit of particle size. This 10 μ is the average particle size.
　粒度分布データは、粒子径スケールに対する積算％や頻度％として表現されるが、積算％のスケールに対する粒子径として表現することができる。例えば、積算％の分布曲線が１０％の横軸と交差するポイントの粒子径を１０％径、５０％の横軸と交差するポイントの粒子径を５０％径、９０％の横軸と交差するポイントの粒子径を９０％径と言うことができ、必要に応じて任意の積算％が用いられる。任意％粒子径の計算方法を図１および下記式（３）、（４）に示す。 The particle size distribution data is expressed as an integrated% or frequency% with respect to the particle size scale, but can also be expressed as a particle size with respect to the integrated% scale. For example, the particle size at the point where the integrated% distribution curve intersects the 10% horizontal axis intersects with the 10% diameter, and the particle size at the point where the 50% horizontal axis intersects with the 50% diameter and 90% horizontal axis. The particle size of the point can be said to be 90%, and an arbitrary integrated% is used if necessary. The calculation method of the arbitrary% particle size is shown in FIG. 1 and the following formulas (3) and (4).
Figure JPOXMLDOC01-appb-M000003
 　積算％Ｑａにおける任意％粒子径ｘａを求め、このｘａの両側の２つの粒子径ｘｊ＋１およびｘｊにおける積算％Ｑｊ＋１およびＱｊが既知であるとき、積算％Ｑａにおける任意％粒子径ｘａは、上記式（３）及び（４）を用いて計算することができる。５０％粒子径がメディアン径となり、Ｑａを５０％として計算することでメディアン径を求めることができる。また出現される頻度（％）の比率が最も大きい粒径によってモード径を求めることができる。
Figure JPOXMLDOC01-appb-M000003
 Obtains any% particle size x a in cumulative% Q a, when cumulative% Q j + 1 and Q j in the x 2 one particle size on either side of a x j + 1 and x j are known, any% in cumulative% Q a The particle size x a can be calculated using the above equations (3) and (4). The 50% particle size becomes the median diameter, and the median diameter can be obtained by calculating with Q a as 50%. Further, the mode diameter can be obtained from the particle size having the largest ratio of appearance frequency (%).
　また本発明のセルロースナノクリスタル分散液においては、セルロースナノクリスタルがネバードライ処理を経たものであることが好適であるが、セルロースナノクリスタル分散液中のセルロースナノクリスタルが、ネバードライ処理を経たものか、或いは乾燥固化処理を経たものであるかについては、セルロースナノクリスタル分散液についての分子運動性と分散性の違いについて、パルスＮＭＲによる緩和時間測定解析及びクライオＳＥＭ観察によって評価することができる。
　すなわち、セルロースナノクリスタル分散液について、Ｂｒｕｋｅｒ製ＴＤ－ＮＭＲ　ＴＨＥ　ＭＩＮＩＳＰＥＣ　ＭＱ２０を用いて、パルスＮＭＲのソリッドエコー法で測定された自由誘導減衰（Ｍ（ｔ））を、下記式（５）を用いて、解析ソフト（ＴＤＮＭＲ－Ａ）によりフィッティングを行い、１成分（α）（成分（α）：分子運動性が低く分子運動が拘束されている最も運動性の低い成分）に近似して解析することができる。さらに下記式（６）、式（７）を用いることにより、２成分以上（上記成分（α）、成分（β）：成分（α）より分子運動性がより高く分子運動が拘束されていない成分、成分（γ）：成分（β）よりも運動性が高い成分）において解析できるかどうかを検討することができ、解析ソフト上でエラーが返される場合、２成分以上は存在しないことが示唆される。 Further, in the cellulose nanocrystal dispersion of the present invention, it is preferable that the cellulose nanocrystals have undergone the never dry treatment, but the cellulose nanocrystals in the cellulose nanocrystal dispersion have undergone the never dry treatment. Or, whether or not the cellulose nanocrystal dispersion has undergone the dry solidification treatment can be evaluated by relaxation time measurement analysis by pulse NMR and cryo-SEM observation for the difference in molecular motility and dispersibility of the cellulose nanocrystal dispersion.
That is, for the cellulose nanocrystal dispersion, the free induction decay (M (t)) measured by the solid echo method of pulse NMR using Bruker's TD-NMR THE MINISPEC MQ20 was carried out using the following formula (5). , Fitting with analysis software (TDNMR-A), and analyze by approximating one component (α) (component (α): the component with low molecular motion and the lowest molecular motion in which molecular motion is constrained). Can be done. Further, by using the following formulas (6) and (7), two or more components (component (α), component (β): a component having higher molecular motility than the component (α) and whose molecular motion is not constrained). , Component (γ): A component with higher motility than component (β)) can be examined, and if an error is returned on the analysis software, it is suggested that two or more components do not exist. To.
Ｍ（ｔ）＝αｅｘｐ｛－（１／Ｗａ）×（ｔ／Ｔα）×Ｗａ｝・・・（５）
Ｍ（ｔ）＝αｅｘｐ｛－（１／Ｗａ）×（ｔ／Ｔα）×Ｗａ｝
　　＋βｅｘｐ｛－（１／Ｗａ）×（ｔ／Ｔβ）×Ｗａ｝・・・（６）
Ｍ（ｔ）＝αｅｘｐ｛－（１／Ｗａ）×（ｔ／Ｔα）×Ｗａ｝
　　＋βｅｘｐ｛－（１／Ｗａ）×（ｔ／Ｔβ）×Ｗａ｝
　　＋γｅｘｐ｛－（１／Ｗａ）×（ｔ／Ｔγ）×Ｗａ｝・・・（７） M (t) = αexp {-(1 / Wa) x (t / Tα) x Wa} ... (5)
M (t) = αexp {-(1 / Wa) x (t / Tα) x Wa}
+ Βexp {-(1 / Wa) x (t / Tβ) x Wa} ... (6)
M (t) = αexp {-(1 / Wa) x (t / Tα) x Wa}
+ Βexp {-(1 / Wa) x (t / Tβ) x Wa}
+ Γexp {-(1 / Wa) x (t / Tγ) x Wa} ... (7)
　上記（５）～（７）中の記号は以下のとおりである。
α：成分（α）のプロトン比率（％）
Ｔα：成分（α）のＴ２緩和時間（μｓｅｃ）
β：成分（β）のプロトン比率（％）
Ｔβ：成分（β）のＴ２緩和時間（μｓｅｃ）
γ：成分（γ）のプロトン比率（％）
Ｔγ：成分（γ）のＴ２緩和時間（μｓｅｃ）
ｔ：観測時間（μｓｅｃ）
Ｗａ：形状係数（１＜Ｗａ＜２） The symbols in (5) to (7) above are as follows.
α: Proton ratio (%) of component (α)
Tα: T2 relaxation time (μsec) of component (α)
β: Proton ratio (%) of component (β)
Tβ: T2 relaxation time (μsec) of component (β)
γ: Proton ratio (%) of component (γ)
Tγ: T2 relaxation time (μsec) of component (γ)
t: Observation time (μsec)
Wa: Shape coefficient (1 <Wa <2)
　ネバードライ処理によるセルロースナノクリスタルを濃縮することによって得られた分散液（後述する実施例１に相当）は、スプレードライなどの乾燥を経てから分散機を用いて再分散処理した分散液（後述する比較例１に相当）に比べて粘度と透明性が高い分散液になる。
　すなわち、後述する実施例の結果からも明らかなように、ネバードライ処理によるセルロースナノクリスタル分散液である実施例１においては、上記式（５）～（７）に従って解析した結果、緩和時間の短い成分（α）のみの１成分での数値の解析結果が得られている。このことは、ネバードライ処理によるセルロースナノクリスタルのみが溶媒中に存在し、１成分の均一な運動性を有していることを示しており、分散液中でのセルロースナノクリスタルの均質性の良さを示している。
　また、実施例１のセルロースナノクリスタル分散液のクライオＳＥＭ観察像を示す図２から明らかなように、ネバードライ処理によるセルロースナノクリスタルは、分散液中で微細且つ均質に分散されていることが観察される。この結果はパルスＮＭＲの解析結果と相関があることが示唆されている。 The dispersion obtained by concentrating the cellulose nanocrystals by the never-dry treatment (corresponding to Example 1 described later) is a dispersion treated by spray-drying or the like and then redispersed using a disperser (described later). It becomes a dispersion liquid having higher viscosity and transparency than (corresponding to Comparative Example 1).
That is, as is clear from the results of Examples described later, in Example 1, which is a cellulose nanocrystal dispersion liquid obtained by never-drying, as a result of analysis according to the above formulas (5) to (7), the relaxation time is short. The analysis result of the numerical value with only one component (α) is obtained. This indicates that only the cellulose nanocrystals subjected to the never-dry treatment are present in the solvent and have uniform motility of one component, and the homogeneity of the cellulose nanocrystals in the dispersion is good. Is shown.
Further, as is clear from FIG. 2 showing the cryo-SEM observation image of the cellulose nanocrystal dispersion liquid of Example 1, it was observed that the cellulose nanocrystals subjected to the never-dry treatment were finely and uniformly dispersed in the dispersion liquid. Will be done. It is suggested that this result correlates with the analysis result of pulse NMR.
　これに対して、乾燥処理による固化を経たセルロースナノクリスタル分散液である比較例１においては、上記式（５）～（７）に従って解析した結果、緩和時間の短い成分（α）及び緩和時間のより長い成分（β）の２成分での数値の解析結果が得られている。このことは、乾燥固化を経たセルロースナノクリスタル及びさらに再分散化に限度があり凝集化したセルロースナノクリスタルの２成分が溶媒中に存在し、均一でない運動性を有していることを示しており、分散液中でのセルロースナノクリスタルの不均質性を示している。
　また、比較例１のセルロースナノクリスタル分散液のクライオＳＥＭ観察像を示す図３から明らかなように、凝集化したセルロースナノクリスタルが存在し均質な分散ではない様子が観察され、この結果はパルスＮＭＲの解析結果と相関があることが示唆されている。 On the other hand, in Comparative Example 1, which is a cellulose nanocrystal dispersion liquid that has been solidified by a drying treatment, as a result of analysis according to the above formulas (5) to (7), the component (α) having a short relaxation time and the relaxation time Numerical analysis results for the two components of the longer component (β) have been obtained. This indicates that the two components of the cellulose nanocrystals that have undergone dry solidification and the cellulose nanocrystals that have been redispersed and aggregated are present in the solvent and have non-uniform motility. , Shows the inhomogeneity of cellulose nanocrystals in the dispersion.
Further, as is clear from FIG. 3 showing a cryo-SEM observation image of the cellulose nanocrystal dispersion liquid of Comparative Example 1, it was observed that aggregated cellulose nanocrystals were present and the dispersion was not uniform, and the result was pulse NMR. It is suggested that there is a correlation with the analysis results of.
　本発明の分散液においては、セルロースナノクリスタルは、硫酸基及び／又はスルホ基、及びカルボキシル基等のアニオン性官能基の総量が０．１７ｍｍｏｌ／ｇより多く且つ４．０ｍｍｏｌ／ｇ以下の範囲で含有していることが好適であり、上記範囲よりもアニオン性官能基の総量が少ない場合には、上記範囲にある場合に比して、十分な自己組織化構造が形成されず、所望のガスバリア性が得られないおそれがある。その一方上記範囲よりもアニオン性官能基の総量が多い場合は、セルロースナノクリスタルの結晶構造が維持できず、かえってガスバリア性を損なうおそれがある。
　尚、本明細書において、硫酸基は、硫酸エステル基を含む概念である。 In the dispersion of the present invention, the cellulose nanocrystal has a total amount of anionic functional groups such as sulfate group and / or sulfo group and carboxyl group of more than 0.17 mmol / g and 4.0 mmol / g or less. It is preferable that the mixture is contained, and when the total amount of anionic functional groups is smaller than the above range, a sufficient self-assembled structure is not formed as compared with the case where the total amount of anionic functional groups is in the above range, and a desired gas barrier is not formed. There is a risk that sex cannot be obtained. On the other hand, when the total amount of anionic functional groups is larger than the above range, the crystal structure of the cellulose nanocrystals cannot be maintained, and the gas barrier property may be impaired.
In addition, in this specification, a sulfuric acid group is a concept including a sulfuric acid ester group.
　本発明においては、セルロースナノクリスタルが、硫酸処理により加水分解されたセルロースナノクリスタルであることにより、自己組織化構造の形成に寄与する硫酸基及び／又はスルホ基を既に含有していることから特に好ましい。すなわち、セルロースナノクリスタルには、セルロース繊維を硫酸処理或いは塩酸処理により酸加水分解するものがあるが、塩酸処理によるセルロースナノクリスタルは硫酸基及び／又はスルホ基を有しないため、自己組織化構造の形成に寄与する硫酸基及び／又はスルホ基を有する、硫酸処理によるセルロースナノクリスタルに比してバリア性を向上できない。
　本発明のセルロースナノクリスタルが有するアニオン性官能基は、後述するセルロースナノクリスタルの親水化処理の方法によって決まり、特にカルボキシル基、リン酸基、硫酸基及び／又はスルホ基であることが好適である。これにより前述した自己組織化構造が効率よく形成され、ガスバリア性が向上する。 In the present invention, since the cellulose nanocrystal is a cellulose nanocrystal hydrolyzed by sulfuric acid treatment, it already contains a sulfuric acid group and / or a sulfo group that contributes to the formation of a self-assembled structure. preferable. That is, some cellulose nanocrystals acid-hydrolyze cellulose fibers by sulfuric acid treatment or hydrochloric acid treatment, but since cellulose nanocrystals by hydrochloric acid treatment do not have sulfuric acid groups and / or sulfo groups, they have a self-assembled structure. Barrier properties cannot be improved as compared with cellulose nanocrystals treated with sulfuric acid, which have a sulfuric acid group and / or a sulfo group that contribute to the formation.
The anionic functional group contained in the cellulose nanocrystal of the present invention is determined by the method for hydrophilizing the cellulose nanocrystal described later, and is particularly preferably a carboxyl group, a phosphoric acid group, a sulfate group and / or a sulfo group. .. As a result, the above-mentioned self-organizing structure is efficiently formed, and the gas barrier property is improved.
　本発明においてセルロースナノクリスタルは、硫酸基及び／又はスルホ基、並びにアニオン性官能基の総量が上記した範囲にあり、結晶化度が６０％以上の範囲にあることが望ましい。
　またセルロースナノクリスタルは、繊維径が５０ｎｍ以下でアスペクト比が５～５０であるセルロースナノクリスタルであることが好適である。 In the present invention, it is desirable that the total amount of the sulfate group and / or the sulfo group and the anionic functional group of the cellulose nanocrystal is in the above range and the crystallinity is in the range of 60% or more.
Further, the cellulose nanocrystal is preferably a cellulose nanocrystal having a fiber diameter of 50 nm or less and an aspect ratio of 5 to 50.
（セルロースナノクリスタル分散液の製造方法）
　上述した特徴を有する本発明のセルロースナノクリスタル分散液は、セルロースナノクリスタルの調製において、パウダー等の固形化を経ていない（ネバードライ処理）セルロースナノクリスタル分散液であることが重要である。前述したとおり、固形化されたセルロースナノクリスタルを用いて分散液を調製すると、固形化処理や固形状のセルロースナノクリスタルの分散処理等により製造工程が煩雑になるだけでなく、ガスバリア性が低下するという問題がある。すなわち、乾燥処理に付され固形化されたセルロースナノクリスタルは分散液中で繊維の配向が整いにくく、緻密な自己組織化構造を形成することが困難であり、本発明の分散液に比してガスバリア性が劣っている。
　従って本発明のセルロースナノクリスタル分散液は、セルロース原料を硫酸処理することにより得られた、硫酸基及び／又はスルホ基含有セルロースナノクリスタルを、親水化処理し、親水化処理工程の後、遠心分離工程、及び濾過分離工程に付することにより得られた分散液であり、固形化のための噴霧乾燥（スプレードライ）工程等を経ることはない。 (Manufacturing method of cellulose nanocrystal dispersion)
In the preparation of cellulose nanocrystals, it is important that the cellulose nanocrystal dispersion liquid of the present invention having the above-mentioned characteristics is a cellulose nanocrystal dispersion liquid that has not undergone solidification such as powder (never dry treatment). As described above, when the dispersion liquid is prepared using the solidified cellulose nanocrystals, not only the manufacturing process becomes complicated due to the solidification treatment and the dispersion treatment of the solid cellulose nanocrystals, but also the gas barrier property is lowered. There is a problem. That is, the cellulose nanocrystals that have been subjected to the drying treatment and solidified are difficult to align the fibers in the dispersion liquid, and it is difficult to form a dense self-assembled structure, as compared with the dispersion liquid of the present invention. Poor gas barrier property.
Therefore, in the cellulose nanocrystal dispersion of the present invention, a cellulose nanocrystal containing a sulfuric acid group and / or a sulfo group obtained by treating a cellulose raw material with sulfuric acid is hydrophilized, and after the hydrophilization treatment step, centrifugation is performed. It is a dispersion obtained by subjecting it to a step and a filtration separation step, and does not undergo a spray drying step or the like for solidification.
［セルロースナノクリスタル］
　セルロースナノクリスタルは、パルプなどのセルロース繊維を硫酸や塩酸で酸加水分解処理することにより得られる、ロッド状のセルロース結晶繊維であるが、本発明においては、自己組織化構造の形成に寄与可能な硫酸基及び／又はスルホ基を有する、硫酸処理によるセルロースナノクリスタルを使用する。
　セルロースナノクリスタルは、硫酸基及び／又はスルホ基を０．１８～４．０ｍｍｏｌ／ｇ、特に０．２０～２．０ｍｍｏｌ／ｇの量で含有することが好適である。またセルロースナノクリスタルは、前述したとおり、繊維径が５０ｎｍ以下、特に２～５０ｎｍの範囲にあり、繊維長が１００～５００ｎｍの範囲にあり、アスペクト比が５～５０の範囲にあり、結晶化度が６０％以上、特に７０％以上であるものを好適に用いることができる。 [Cellulose nanocrystal]
Cellulose nanocrystals are rod-shaped cellulose crystal fibers obtained by acid-hydrolyzing cellulose fibers such as pulp with sulfuric acid or hydrochloric acid, but in the present invention, they can contribute to the formation of a self-assembled structure. Sulfuric acid-treated cellulose nanocrystals with sulfuric acid and / or sulfo groups are used.
Cellulose nanocrystals preferably contain a sulfate group and / or a sulfo group in an amount of 0.18 to 4.0 mmol / g, particularly 0.20 to 2.0 mmol / g. As described above, the cellulose nanocrystals have a fiber diameter of 50 nm or less, particularly in the range of 2 to 50 nm, a fiber length in the range of 100 to 500 nm, an aspect ratio in the range of 5 to 50, and a degree of crystallinity. 60% or more, particularly 70% or more can be preferably used.
［親水化処理］
　本発明においては、上述した硫酸基及び／又はスルホ基を有するセルロースナノクリスタルの親水化処理を行うことにより、硫酸基及び／又はスルホ基量を調整、或いは、カルボキシル基、リン酸基等のアニオン性官能基をセルロースの６位の水酸基に導入し、硫酸基、スルホ基、カルボキシル基、リン酸基等のアニオン性官能基の総量が０．１７ｍｍｏｌ／ｇより多く且つ４．０ｍｍｏｌ／ｇ以下、特に０．２０～２．０ｍｍｏｌ／ｇの範囲にあるセルロースナノクリスタルを調製する。
　親水化処理としては、ネバードライ処理、又はネバードライ処理と、水溶性カルボジイミド、硫酸、三酸化硫黄－ピリジン錯体、リン酸－尿素、ＴＥＭＰＯ触媒、酸化剤の何れかを用いた処理とを組み合わせて行う。カルボジイミド、硫酸、三酸化硫黄－ピリジン錯体の何れかを用いた処理により、セルロースナノクリスタルの硫酸基及び／又はスルホ基量が調整されると共に、更にナノセルロースが更に短繊維化される。またリン酸－尿素又はＴＥＭＰＯ触媒、酸化剤の何れかを用いた処理により、リン酸基又はカルボキシル基のアニオン性官能基が導入されて、セルロースナノクリスタルの総アニオン性官能基量が上記範囲に調整される。
　尚、親水化処理は、アニオン性官能基の総量が上記範囲となる限り、いずれか一つの処理を行えばよいが、同一の処理を複数回、或いは他の処理と組み合わせて複数回行ってもよい。 [Hydrophilic treatment]
In the present invention, the amount of sulfate group and / or sulfo group is adjusted or anions such as carboxyl group and phosphoric acid group are adjusted by hydrophilizing the cellulose nanocrystal having a sulfate group and / or sulfo group described above. A sex functional group is introduced into the hydroxyl group at the 6-position of cellulose, and the total amount of anionic functional groups such as sulfate group, sulfo group, carboxyl group and phosphoric acid group is more than 0.17 mmol / g and 4.0 mmol / g or less. In particular, cellulose nanocrystals in the range of 0.20 to 2.0 mmol / g are prepared.
The hydrophilization treatment is a combination of a never-dry treatment or a never-dry treatment and a treatment using any of water-soluble carbodiimide, sulfuric acid, sulfur trioxide-pyridine complex, phosphoric acid-urea, TEMPO catalyst, and oxidant. Do. Treatment with any of carbodiimide, sulfuric acid, and sulfur trioxide-pyridine complex adjusts the amount of sulfuric acid group and / or sulfo group of the cellulose nanocrystal, and further shortens the nanocellulose. Further, by treatment with either phosphoric acid-urea, a TEMPO catalyst, or an oxidizing agent, an anionic functional group of a phosphoric acid group or a carboxyl group is introduced, and the total amount of anionic functional groups of the cellulose nanocrystal is within the above range. It will be adjusted.
The hydrophilization treatment may be performed by any one of them as long as the total amount of anionic functional groups is within the above range, but the same treatment may be performed a plurality of times or a plurality of times in combination with other treatments. Good.
＜ネバードライ処理による親水化処理＞
　セルロースナノクリスタルは、スプレードライ、加熱、減圧などによる乾燥処理を行ってパウダー等の固形化を経るが、乾燥処理による固形化の際にセルロースナノクリスタルに含有するアニオン性官能基の一部が脱離して親水性が低下する。すなわち、アニオン性官能基を含有するセルロースナノクリスタルについてパウダー等の固形化を経ないネバードライ処理は親水化処理として挙げられる。アニオン性官能基は、硫酸基及び／又はスルホ基、リン酸基、カルボキシル基などが挙げられる。 <Hydrophilic treatment by never dry treatment>
Cellulose nanocrystals undergo drying treatments such as spray drying, heating, and reduced pressure to solidify powders and the like, but when solidified by drying treatments, some of the anionic functional groups contained in the cellulose nanocrystals are removed. Separation reduces hydrophilicity. That is, a never-drying treatment of cellulose nanocrystals containing anionic functional groups without solidification of powder or the like can be mentioned as a hydrophilic treatment. Examples of the anionic functional group include a sulfate group and / or a sulfo group, a phosphoric acid group, a carboxyl group and the like.
＜カルボジイミドを用いた親水化処理＞
　カルボジイミドを用いた処理においては、ジメチルホルムアミド等の溶媒中でセルロースナノクリスタルとカルボジイミドを撹拌し、これに硫酸を添加した後、０～８０℃の温度で５～３００分反応させて硫酸エステルとする。カルボジイミド及び硫酸は、セルロースナノクリスタル１ｇ（固形分）に対して５～３０ｍｍｏｌ及び５～３０ｍｍｏｌの量で使用することが好ましい。
　次いで水酸化ナトリウム等のアルカリ性化合物を添加して、セルロースナノクリスタルに導入されたスルホ基をＨ型からＮａ型に変換することが、収率を向上する上で好ましい。その後、透析膜等を用いた濾過処理に付して不純物等を除去することにより、硫酸基及び／又はスルホ基変性セルロースナノクリスタルが調製される。
　カルボジイミドとしては、分子内にカルボジイミド基（－Ｎ＝Ｃ＝Ｎ－）を有する水溶性化合物である１－エチル－３－（３－ジメチルアミノプロピル）カルボジイミド等を例示できる。また有機溶媒に溶解するジシクロヘキシルカルボジイミド等を使用することもできる。 <Hydrophilic treatment using carbodiimide>
In the treatment using carbodiimide, cellulose nanocrystals and carbodiimide are stirred in a solvent such as dimethylformamide, sulfuric acid is added thereto, and then the reaction is carried out at a temperature of 0 to 80 ° C. for 5 to 300 minutes to obtain a sulfuric acid ester. .. Carbodiimide and sulfuric acid are preferably used in an amount of 5 to 30 mmol and 5 to 30 mmol with respect to 1 g (solid content) of cellulose nanocrystals.
Next, it is preferable to add an alkaline compound such as sodium hydroxide to convert the sulfo group introduced into the cellulose nanocrystal from H type to Na type in order to improve the yield. After that, impurities and the like are removed by filtration using a dialysis membrane or the like to prepare cellulose nanocrystals modified with a sulfate group and / or a sulfo group.
Examples of the carbodiimide include 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide, which is a water-soluble compound having a carbodiimide group (-N = C = N-) in the molecule. Further, dicyclohexylcarbodiimide or the like dissolved in an organic solvent can also be used.
＜硫酸を用いた親水化処理＞
　本発明で使用するセルロースナノクリスタルは、セルロース繊維を硫酸で加水分解処理して成るものであるが、このセルロースナノクリスタルを更に硫酸を用いて親水化処理する。硫酸は、セルロースナノクリスタル１ｇ（固形分）に対して４０～６０質量％で使用することが好ましい。４０～６０℃の温度で５～３００分反応させ、その後、透析膜等を用いた濾過処理に付して不純物等を除去することにより、硫酸基及び／又はスルホ基変性セルロースナノクリスタルが調製される。 <Hydrophilic treatment with sulfuric acid>
The cellulose nanocrystals used in the present invention are formed by hydrolyzing cellulose fibers with sulfuric acid, and the cellulose nanocrystals are further hydrophilized with sulfuric acid. Sulfuric acid is preferably used in an amount of 40 to 60% by mass with respect to 1 g (solid content) of cellulose nanocrystals. Sulfate group and / or sulfo group-modified cellulose nanocrystals are prepared by reacting at a temperature of 40 to 60 ° C. for 5 to 300 minutes and then subjecting to filtration treatment using a dialysis membrane or the like to remove impurities and the like. To.
＜三酸化硫黄－ピリジン錯体を用いた親水化処理＞
　三酸化硫黄－ピリジン錯体を用いた処理においては、ジメチルスルホキシド中でセルロースナノクリスタルと三酸化硫黄－ピリジン錯体を、０～６０℃の温度で５～２４０分反応させることにより、セルロースグルコースユニットの６位の水酸基に硫酸基及び／又はスルホ基を導入する。
　三酸化硫黄－ピリジン錯体は、セルロースナノクリスタル１ｇ（固形分）に対して０．５～４ｇの質量で配合することが好ましい。
　反応後、水酸化ナトリウム等のアルカリ性化合物を添加して、セルロースナノクリスタルに導入された硫酸基及び／又はスルホ基をＨ型からＮａ型に変換することが、収率を向上する上で好ましい。その後、ジメチルホルムアミド又はイソプロピルアルコールを添加して、遠心分離等によって洗浄した後、透析膜等を用いた濾過処理によって不純物等を除去し、得られた濃縮液を水に分散させることにより、硫酸基及び／又はスルホ基変性セルロースナノクリスタルが調製される。 <Hydrophilic treatment using sulfur trioxide-pyridine complex>
In the treatment using the sulfur trioxide-pyridine complex, the cellulose nanocrystal and the sulfur trioxide-pyridine complex are reacted in dimethylsulfoxide at a temperature of 0 to 60 ° C. for 5 to 240 minutes to form 6 of the cellulose glucose unit. A sulfate group and / or a sulfo group is introduced into the hydroxyl group at the position.
The sulfur trioxide-pyridine complex is preferably blended in a mass of 0.5 to 4 g with respect to 1 g (solid content) of cellulose nanocrystals.
After the reaction, it is preferable to add an alkaline compound such as sodium hydroxide to convert the sulfate group and / or the sulfo group introduced into the cellulose nanocrystal from the H type to the Na type in order to improve the yield. Then, dimethylformamide or isopropyl alcohol is added, and the mixture is washed by centrifugation or the like, impurities and the like are removed by filtration using a dialysis membrane or the like, and the obtained concentrate is dispersed in water to form a sulfate group. And / or a sulfo group-modified cellulose nanocrystal is prepared.
＜リン酸－尿素を用いた親水化処理＞
　リン酸－尿素を用いた親水化処理は、リン酸－尿素を用いてリン酸基を導入する従来公知の処理と同様に行うことができる。具体的には、尿素含有化合物の存在下で、セルロースナノクリスタルとリン酸基含有化合物を、１３５～１８０℃の温度で５～１２０分反応させることによって、セルロースグルコースユニットの水酸基にリン酸基を導入する。
　リン酸基含有化合物としては、リン酸、リン酸のリチウム塩、リン酸のナトリウム塩、リン酸のカリウム塩、リン酸のアンモニウム塩等を例示できる。中でもリン酸二水素ナトリウム、リン酸二水素アンモニウム、リン酸等を好適に単独または混合して使用できる。リン酸基含有化合物は、セルロースナノクリスタル１０ｇ（固形分）に対して１０～１００ｍｍｏｌの量で添加することが好ましい。
　また尿素含有化合物としては、尿素、チオ尿素、ビュウレット、フェニル尿素、ベンジル尿素、ジメチル尿素などを例示できる。中でも尿素を好適に使用できる。尿素含有化合物は、セルロースナノクリスタル１０ｇ（固形分）に対して１５０～２００ｍｍｏｌの量で使用することが好ましい。 <Hydrophilic treatment using phosphoric acid-urea>
The hydrophilization treatment using phosphoric acid-urea can be carried out in the same manner as the conventionally known treatment for introducing a phosphoric acid group using phosphoric acid-urea. Specifically, the cellulose nanocrystal and the phosphate group-containing compound are reacted at a temperature of 135 to 180 ° C. for 5 to 120 minutes in the presence of a urea-containing compound to form a phosphate group on the hydroxyl group of the cellulose glucose unit. Introduce.
Examples of the phosphoric acid group-containing compound include phosphoric acid, a lithium salt of phosphoric acid, a sodium salt of phosphoric acid, a potassium salt of phosphoric acid, and an ammonium salt of phosphoric acid. Among them, sodium dihydrogen phosphate, ammonium dihydrogen phosphate, phosphoric acid and the like can be preferably used alone or in combination. The phosphoric acid group-containing compound is preferably added in an amount of 10 to 100 mmol with respect to 10 g (solid content) of cellulose nanocrystals.
Examples of the urea-containing compound include urea, thiourea, biuret, phenylurea, benzylurea, and dimethylurea. Among them, urea can be preferably used. The urea-containing compound is preferably used in an amount of 150 to 200 mmol with respect to 10 g (solid content) of cellulose nanocrystals.
＜ＴＥＭＰＯ触媒を用いた親水化処理＞
　ＴＥＭＰＯ触媒（２，２，６，６－テトラメチルピペリジン－１－オキシル）を用いた親水化処理は、ＴＥＭＰＯ触媒を用いた従来公知の酸化方法と同様に行うことができる。具体的には、硫酸基及び／又はスルホ基を有するセルロースナノクリスタルを、ＴＥＭＰＯ触媒（２，２，６，６－テトラメチルピペリジン　１－オキシル）を介した水系、常温、常圧の条件下で、セルロースグルコースユニットの６位の水酸基をカルボキシル基に酸化する親水化反応を生じさせる。
　ＴＥＭＰＯ触媒としては、上記２，２，６，６－テトラメチルピペリジン　１－オキシルの他、４－アセトアミドーＴＥＭＰＯ、４－カルボキシーＴＥＭＰＯ、４－フォスフォノキシーＴＥＭＰＯ等のＴＥＭＰＯの誘導体を用いることもできる。
　ＴＥＭＰＯ触媒の使用量は、セルロースナノクリスタル（固形分）１ｇに対して０．０１～１００ｍｍｏｌ、好ましくは０．０１～５ｍｍｏｌの量である。 <Hydrophilic treatment using TEMPO catalyst>
The hydrophilization treatment using a TEMPO catalyst (2,2,6,6-tetramethylpiperidin-1-oxyl) can be carried out in the same manner as a conventionally known oxidation method using a TEMPO catalyst. Specifically, cellulose nanocrystals having a sulfate group and / or a sulfo group are subjected to TEMPO catalyst (2,2,6,6-tetramethylpiperidine 1-oxyl) under aqueous conditions, normal temperature, and normal pressure. , The hydroxyl group at the 6-position of the cellulose glucose unit is oxidized to a carboxyl group to cause a hydrophilic reaction.
As the TEMPO catalyst, in addition to the above 2,2,6,6-tetramethylpiperidin 1-oxyl, TEMPO derivatives such as 4-acetamido-TEMPO, 4-carboxy-TEMPO, and 4-phosphonoxy TEMPO can also be used.
The amount of the TEMPO catalyst used is 0.01 to 100 mmol, preferably 0.01 to 5 mmol, per 1 g of cellulose nanocrystals (solid content).
　また親水化酸化処理時には、単独又はＴＥＭＰＯ触媒と共に、酸化剤、臭化物又はヨウ化物等の共酸化剤を併用することが好適である。
　酸化剤としては、ハロゲン、次亜ハロゲン酸、亜ハロゲン酸、過ハロゲン酸又はそれらの塩、ハロゲン酸化物、過酸化物等公知の酸化剤を例示することができ、特に次亜塩素酸ナトリウムや次亜臭素酸ナトリウムを好適に使用できる。酸化剤は、セルロースナノクリスタル（固形分）１ｇに対して０．５～５００ｍｍｏｌ、好ましくは５～５０ｍｍｏｌの量である。酸化剤を添加して一定時間が経過した後、更に酸化剤を加えることで追酸化処理することもできる。
　また共酸化剤としては、臭化ナトリウム等の臭化アルカリ金属、ヨウ化ナトリウム等のヨウ化物アルカリ金属を好適に使用できる。共酸化剤は、セルロースナノクリスタル（固形分）１ｇに対して０．１～１００ｍｍｏｌ、好ましくは０．５～５ｍｍｏｌの量である。
　また反応液は、水やアルコール溶媒を反応媒体とすることが好ましい。 Further, at the time of hydrophilization oxidation treatment, it is preferable to use an oxidizing agent, a bromide, an iodide or the like in combination with an oxidizing agent or a TEMPO catalyst.
Examples of the oxidizing agent include known oxidizing agents such as halogen, hypobromous acid, hypochlorous acid, perhalogen acid or salts thereof, halogen oxides, and peroxides, and in particular, sodium hypochlorite and the like. Sodium hypobromite can be preferably used. The amount of the oxidizing agent is 0.5 to 500 mmol, preferably 5 to 50 mmol, per 1 g of the cellulose nanocrystal (solid content). After a certain period of time has passed after adding the oxidizing agent, the additional oxidation treatment can be performed by further adding the oxidizing agent.
Further, as the copolymerizer, an alkali metal bromide such as sodium bromide and an alkali metal iodide such as sodium iodide can be preferably used. The amount of the copolymerizer is 0.1 to 100 mmol, preferably 0.5 to 5 mmol, per 1 g of cellulose nanocrystals (solid content).
The reaction solution preferably uses water or an alcohol solvent as a reaction medium.
　親水化処理の反応温度は１～５０℃、特に１０～５０℃の範囲であり、室温であってもよい。また反応時間は１～３６０分、特に６０～２４０分であることが好ましい。
　反応の進行に伴い、セルロース中にカルボキシル基が生成するため、スラリーのｐＨの低下が認められるが、酸化反応を効率よく進行させるため、水酸化ナトリウム等のｐＨ調整剤を用いてｐＨ９～１２の範囲に維持することが望ましい。 The reaction temperature of the hydrophilization treatment is in the range of 1 to 50 ° C., particularly 10 to 50 ° C., and may be room temperature. The reaction time is preferably 1 to 360 minutes, particularly preferably 60 to 240 minutes.
As the reaction progresses, a carboxyl group is generated in the cellulose, so that the pH of the slurry is lowered. However, in order to promote the oxidation reaction efficiently, a pH adjuster such as sodium hydroxide is used to adjust the pH to 9-12. It is desirable to keep it in the range.
［洗浄・解繊処理］
　親水化処理前又は後のセルロースナノクリスタルは、水洗、或いは水を加えながら遠心分離することによって、親水化処理に用いた酸や触媒等を洗浄する。
　次いで、解繊処理を行うことが好ましいが、セルロースナノクリスタルは繊維長が短いことから必ずしも解繊処理を行わなくてもよい。
　尚、微細化装置として超高圧ホモジナイザー、ミキサー、グラインダー等を用い、水等を分散媒として解繊処理を行うことにより、解繊と同時に分散液の調製を行ってもよい。 [Washing / defibration treatment]
The cellulose nanocrystals before or after the hydrophilization treatment are washed with water or centrifuged while adding water to wash the acid, catalyst, etc. used in the hydrophilic treatment.
Next, it is preferable to perform a defibration treatment, but since the cellulose nanocrystal has a short fiber length, the defibration treatment does not necessarily have to be performed.
A dispersion liquid may be prepared at the same time as defibration by using an ultra-high pressure homogenizer, a mixer, a grinder or the like as a miniaturization device and performing a defibration treatment using water or the like as a dispersion medium.
［分散処理］
　親水化処理、或いは必要により解繊処理に付されたセルロースナノクリスタルは、固形化（パウダー状になるように噴霧乾燥）されることなく、分散処理に付される。固形化されていないことにより再分散の必要がなく、生産性及び経済性に優れている。また固形化されていないことにより、前述した緻密な自己組織化構造を形成することが可能となり、優れたガスバリア性を発現することが可能になる。
　分散処理は超音波分散機、ホモジナイザー、ミキサー等の分散機を好適に使用することができ、また、攪拌棒、攪拌石等による攪拌方法を用いても良い。
　分散液の分散媒は、水だけでもよいが、メタノール、エタノール、イソプロパノール等のアルコール、２－ブタノン、アセトン等のケトン、トルエン等の芳香族系溶剤と水との混合溶媒であってもよい。
　セルロースナノクリスタル分散液は、セルロースナノクリスタル（固形分）が０．１～９０質量％の範囲で含有されていることが好適であり、固形分２質量％の水分散で、粘度が５．５～４０ｍＰａ・ｓ（回転式粘度計、温度３０℃、スピンドル回転速度１００ｒｐｍ）、ゼータ電位が－５０～－５５ｍＶの範囲にあり、取扱い性、塗工性に優れている。また固形分２質量％の水分散で、可視光線透過率が４５％Ｔ以上と透明性に優れている。 [Distributed processing]
Cellulose nanocrystals that have been subjected to a hydrophilization treatment or, if necessary, a defibration treatment, are subjected to a dispersion treatment without being solidified (spray-dried so as to become a powder). Since it is not solidified, there is no need for redispersion, and it is excellent in productivity and economy. Further, since it is not solidified, it is possible to form the above-mentioned dense self-assembled structure, and it is possible to exhibit excellent gas barrier properties.
For the dispersion treatment, a disperser such as an ultrasonic disperser, a homogenizer, or a mixer can be preferably used, and a stirring method using a stirring rod, a stirring stone, or the like may be used.
The dispersion medium of the dispersion may be water alone, or may be a mixed solvent of water with an alcohol such as methanol, ethanol or isopropanol, a ketone such as 2-butanone or acetone, or an aromatic solvent such as toluene.
The cellulose nanocrystal dispersion liquid preferably contains cellulose nanocrystals (solid content) in the range of 0.1 to 90% by mass, and is aqueous dispersion having a solid content of 2% by mass and has a viscosity of 5.5. It has a zeta potential in the range of -50 to -55 mV at ~ 40 mPa · s (rotary viscometer, temperature 30 ° C., spindle rotation speed 100 rpm), and is excellent in handleability and coatability. Further, it is excellent in transparency with a visible light transmittance of 45% T or more with water dispersion having a solid content of 2% by mass.
（セルロースナノクリスタル含有コーティング液）
　本発明のセルロースナノクリスタル含有コーティング液においては、セルロースナノクリスタル分散液と共に、水溶性高分子及び無機層状化合物を含有することにより、高湿度条件下においても優れたガスバリア性を発現することができる。すなわち、水酸基含有高分子は、セルロースナノクリスタルと共に緻密な架橋構造を形成することができ、得られる塗膜のガスバリア性が顕著に向上される。また層状無機化合物は、膨潤性及び劈開性を有することから、セルロースナノクリスタルが無機層状化合物の層間を広げるように入り込んで複合化し、層状無機化合物により得られる透過ガスの迂回効果と、セルロースナノクリスタルによる架橋構造とが相俟って、高湿度条件下でも優れたガスバリア性を発現することが可能になる。 (Cellulose nanocrystal-containing coating liquid)
The cellulose nanocrystal-containing coating liquid of the present invention can exhibit excellent gas barrier properties even under high humidity conditions by containing a water-soluble polymer and an inorganic layered compound together with the cellulose nanocrystal dispersion liquid. That is, the hydroxyl group-containing polymer can form a dense crosslinked structure together with the cellulose nanocrystals, and the gas barrier property of the obtained coating film is remarkably improved. In addition, since the layered inorganic compound has swelling property and openness, the cellulose nanocrystals enter and composite so as to widen the layers of the inorganic layered compound, and the permeation gas bypass effect obtained by the layered inorganic compound and the cellulose nanocrystals are obtained. Combined with the cross-linked structure of the above, it becomes possible to exhibit excellent gas barrier properties even under high humidity conditions.
［水溶性高分子］
　本発明のコーティング液に含有される水溶性高分子としては、ポリビニルアルコール、酢酸ビニルアルコール共重合体、エチレンビニルアルコール共重合体、ポリアクリル酸、ポリメタクリル酸、カルボキシルメチルセルロース、澱粉等を例示できるが、ポリビニルアルコールを好適に使用することができる。ポリビニルアルコールは、完全ケン化型で１００～１００００の重合度を有することが好適である。
　水酸基含有高分子は、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で配合されていることが好ましい。 [Water-soluble polymer]
Examples of the water-soluble polymer contained in the coating liquid of the present invention include polyvinyl alcohol, vinyl acetate alcohol copolymer, ethylene vinyl alcohol copolymer, polyacrylic acid, polymethacrylic acid, carboxylmethylcellulose, starch and the like. , Polyvinyl alcohol can be preferably used. Polyvinyl alcohol is preferably a fully saponified type and has a degree of polymerization of 100 to 10000.
The hydroxyl group-containing polymer is preferably blended in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content).
［無機層状化合物］
　無機層状化合物としては、天然又は合成したもの、親水性又は疎水性を示し、溶媒により膨潤して劈開性を示す従来公知のものを使用でき、これに限定されないが、カオリナイト、ディッカイト、ナクライト、ハロイサイト、アンチゴライト、クリソタイル、パイロフィライト、モンモリロナイト、ヘクトライト、マイカ、テトラシリックマイカ、ナトリウムテニオライト、白雲母、マーガライト、タルク、バーミキュライト、金雲母、ザンソフィライト、緑泥石等を例示することができ、合成マイカ（親水性膨潤性）を好適に使用することができる。
　無機層状化合物は、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で配合されていることが好ましい。 [Inorganic layered compound]
As the inorganic layered compound, a naturally or synthetic compound, a conventionally known compound which exhibits hydrophilicity or hydrophobicity and exhibits swelling and cleavability with a solvent can be used, and is not limited to, but is limited to, kaolinite, chlorite, micalite, and the like. Examples of halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, hectrite, mica, tetrasilic mica, sodium teniolite, muscovite, margarite, talc, vermiculite, gold mica, zansophyllite, chlorite, etc. Therefore, synthetic mica (hydrophilic swelling property) can be preferably used.
The inorganic layered compound is preferably blended in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content).
［反応性架橋剤］
　本発明のコーティング液においては、反応性架橋剤として、反応効率の良い多価カルボン酸を使用する。多価カルボン酸としては、クエン酸、シュウ酸、マロン酸等のアルキルジカルボン酸、テレフタル酸、マレイン酸等の芳香族ジカルボン酸、或いはこれらの無水物等を例示することができ、特に無水クエン酸を好適に使用することができる。
　本発明のコーティング液においては、セルロースナノクリスタルがアニオン性官能基を含有することにより、酸性条件下でも凝集することなく安定して分散可能なものであることから、上記多価カルボン酸を好適に使用することができる。
　多価カルボン酸は、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で配合されていることが好ましい。 [Reactive cross-linking agent]
In the coating liquid of the present invention, a polyunsaturated carboxylic acid having good reaction efficiency is used as the reactive cross-linking agent. Examples of the polyvalent carboxylic acid include alkyldicarboxylic acids such as citric acid, oxalic acid and malonic acid, aromatic dicarboxylic acids such as terephthalic acid and maleic acid, and anhydrides thereof, and in particular, citric acid anhydride. Can be preferably used.
In the coating liquid of the present invention, since the cellulose nanocrystal contains an anionic functional group, it can be stably dispersed without agglutination even under acidic conditions. Therefore, the polyvalent carboxylic acid is preferably used. Can be used.
The polyunsaturated carboxylic acid is preferably blended in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content).
［その他］
　本発明のコーティング液においては、上記多価カルボン酸から成る架橋剤と共に酸触媒を含有することが好ましい。このような酸触媒としては、硫酸、酢酸、塩酸等を例示できるが、特に硫酸を好適に用いることができる。酸触媒は、セルロースナノクリスタル１００質量部（固形分）に対して０．０１～１０質量部の範囲で配合されていることが好ましい。
　またセルロースナノクリスタル含有コーティング液には、必要に応じて、充填剤、着色剤、紫外線吸収剤、帯電防止剤、耐水化剤、金属塩、コロイダルシリカ、アルミナゾル、酸化チタン等、公知の添加剤を配合することができる。 [Other]
The coating liquid of the present invention preferably contains an acid catalyst together with the cross-linking agent composed of the polyunsaturated carboxylic acid. Examples of such an acid catalyst include sulfuric acid, acetic acid, hydrochloric acid and the like, and sulfuric acid is particularly preferably used. The acid catalyst is preferably blended in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass (solid content) of the cellulose nanocrystals.
In addition, known additives such as fillers, colorants, ultraviolet absorbers, antistatic agents, water resistant agents, metal salts, colloidal silica, alumina sol, titanium oxide, etc. are added to the cellulose nanocrystal-containing coating liquid, if necessary. Can be blended.
（成形体）
　本発明の成形体は、本発明のセルロースナノクリスタル含有コーティング液に含有されていたセルロースナノクリスタルと多価カチオン樹脂とを含有する層が基材上に形成されて成る成形体であり、セルロースナノクリスタルを固形分として１ｍ２当たり１．０ｇ含有する場合の２３℃５０％ＲＨにおける酸素透過度が３．８（ｃｃ／ｍ２・ｄａｙ・ａｔｍ）未満と、優れた酸素バリア性を発現可能であると共に、基材上にセルロースナノクリスタルと多価カチオン樹脂とを含有する層を形成した場合に、該層と基材層との密着性を顕著に向上可能な成形体である。
　また本発明の成形体においては、多価カチオン樹脂の存在により疎水性の樹脂から成る層との界面剥離強度が向上されていることから、基材、特に熱可塑性樹脂から成る基材とセルロースナノクリスタル及び多価カチオン樹脂含有層の界面剥離強度が２．３（Ｎ／１５ｍｍ）以上であり、層間剥離の発生が有効に防止されている。 (Molded body)
The molded product of the present invention is a molded product in which a layer containing the cellulose nanocrystals and the polyvalent cationic resin contained in the cellulose nanocrystal-containing coating liquid of the present invention is formed on a substrate, and the cellulose nano is formed. When the crystal is contained in an amount of 1.0 g per 1 m 2 as a solid content, the oxygen permeability at 23 ° C. and 50% RH is less than 3.8 (cc / m 2 · day · atm), and excellent oxygen barrier properties can be exhibited. At the same time, when a layer containing cellulose nanocrystals and a polyvalent cationic resin is formed on a base material, the adherence between the layer and the base material layer can be remarkably improved.
Further, in the molded product of the present invention, since the interfacial peel strength with the layer made of the hydrophobic resin is improved by the presence of the polyvalent cation resin, the base material, particularly the base material made of a thermoplastic resin and the cellulose nano are made. The interfacial peel strength of the crystal and the polyvalent cationic resin-containing layer is 2.3 (N / 15 mm) or more, and the occurrence of delamination is effectively prevented.
　本発明の成形体においては、多価カチオン樹脂から成る層上に前述したセルロースナノクリスタル含有コーティング液から成る層を形成することによって、優れたガスバリア性及び基材への密着性を発現可能な混合状態を有する層を形成できる。すなわち、本発明のコーティング液及び多価カチオン樹脂により形成される層の混合状態を定量的に表現することは困難であるが、前述したセルロースナノクリスタルが有する自己組織化構造が維持された状態で多価カチオン樹脂及びセルロースナノクリスタルが混合されることによって初めて形成される。本発明のコーティング液及び多価カチオン樹脂により形成される層の内部は最外部の表面付近から基材方向までセルロースナノクリスタルと多価カチオン樹脂が存在している特徴を有している。 In the molded product of the present invention, by forming a layer made of the above-mentioned cellulose nanocrystal-containing coating liquid on a layer made of a multivalent cationic resin, a mixture capable of exhibiting excellent gas barrier properties and adhesion to a base material can be exhibited. A layer with a state can be formed. That is, although it is difficult to quantitatively express the mixed state of the layer formed by the coating liquid and the polyvalent cationic resin of the present invention, the self-assembled structure of the cellulose nanocrystals described above is maintained. It is first formed by mixing a polyvalent cationic resin and cellulose nanocrystals. The inside of the layer formed by the coating liquid of the present invention and the polyvalent cationic resin has a feature that cellulose nanocrystals and the polyvalent cationic resin are present from the vicinity of the outermost surface to the direction of the base material.
［多価カチオン樹脂］
　本発明の成形体に使用する多価カチオン樹脂としては、水溶性あるいは水性分散性の多価カチオン性官能基を含有する樹脂である。このような多価カチオン樹脂としては、ポリエチレンイミン、ポリアリルアミン、ポリアミンポリアミドエピクロロヒドリン、ポリアミンエピクロロヒドリン等の水溶性アミンポリマー、ポリアクリルアミド、ポリ（ジアリルジメチルアンモニウム塩）、ジシアンジアミドホルマリン、ポリ（メタ）アクリレート、カチオン化澱粉、カチオン化ガム、ゼラチン、キチン、キトサン等を挙げることができるが、中でも水溶性アミンポリマー、特にポリエチレンイミンを好適に使用することができる。 [Multivalent cationic resin]
The polyvalent cationic resin used in the molded product of the present invention is a resin containing a water-soluble or water-dispersible polyvalent cationic functional group. Examples of such a polyvalent cationic resin include water-soluble amine polymers such as polyethyleneimine, polyallylamine, polyamine polyamide epichlorohydrin, and polyamine epichlorohydrin, polyacrylamide, poly (diallyldimethylammonium salt), dicyandiamideformalin, and poly. Examples thereof include (meth) acrylate, cationized starch, cationized gum, gelatin, chitin, chitosan and the like, and among them, water-soluble amine polymers, particularly polyethyleneimine, can be preferably used.
［基材］
　基材としては、これに限定されないが、熱可塑性樹脂から成る基材や紙製基材を挙げることができる。
　熱可塑性樹脂から成る基材としては、熱可塑性樹脂を用い、押出成形、射出成形、ブロー成形、延伸ブロー成形或いはプレス成形等の手段で製造された、フィルム、シート、或いはボトル状、カップ状、トレイ状、パウチ状等の成形体を例示できる。
　熱可塑性樹脂から成る基材の厚みは、積層体の形状や用途等によって一概に規定できないが、フィルムの場合で５～５０μｍの範囲にあることが好適である。 [Base material]
Examples of the base material include, but are not limited to, a base material made of a thermoplastic resin and a paper base material.
As the base material made of thermoplastic resin, a thermoplastic resin is used, and a film, sheet, bottle-shaped, cup-shaped, manufactured by means such as extrusion molding, injection molding, blow molding, stretch blow molding or press molding, etc. Examples of tray-shaped and pouch-shaped molded bodies can be exemplified.
The thickness of the base material made of a thermoplastic resin cannot be unconditionally defined depending on the shape and application of the laminate, but in the case of a film, it is preferably in the range of 5 to 50 μm.
　熱可塑性樹脂としては、低－、中－或いは高－密度ポリエチレン、線状低密度ポリエチレン、ポリプロピレン、エチレン－プロピレン共重合体、エチレン－ブテン－共重合体、アイオノマー、エチレン－酢酸ビニル共重合体、エチレン－ビニルアルコール共重合体等のオレフィン系共重合体；ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリエチレンテレフタレート／イソフタレート、ポリエチレンナフタレート等の芳香族ポリエステル；ポリ乳酸、ポリカプロラクトン、ポリブチレンサクシネート等の脂肪族ポリエステル；ナイロン６、ナイロン６，６、ナイロン６，１０、メタキシリレンアジパミド等のポリアミド；ポリスチレン、スチレン－ブタジエンブロック共重合体、スチレン－アクリロニトリル共重合体、スチレン－ブタジエン－アクリロニトリル共重合体（ＡＢＳ樹脂）等のスチレン系共重合体；ポリ塩化ビニル、塩化ビニル－酢酸ビニル共重合体等の塩化ビニル系共重合体；ポリメチルメタクリレート、メチルメタクリレート・エチルアクリレート共重合体等のアクリル系共重合体；ポリカーボネート、セルロース系樹脂；アセチルセルロース、セルロースアセチルプロピオネート、セルロースアセテートブチレート、セロファン等の再生セルロース等を例示できるが、ポリエチレンテレフタレートを好適に用いることができる。
　熱可塑性樹脂には、所望に応じて顔料、酸化防止剤、帯電防止剤、紫外線吸収剤、滑剤等の添加剤の１種或いは２種類以上を配合することができる。 Examples of the thermoplastic resin include low-, medium- or high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene-copolymer, ionomer, ethylene-vinyl acetate copolymer, and the like. Olefin-based copolymers such as ethylene-vinyl alcohol copolymers; aromatic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate, and polyethylene naphthalate; fats such as polylactic acid, polycaprolactone, and polybutylene succinate. Group polyesters; polyamides such as nylon 6, nylon 6,6, nylon 6,10, metaxylylene adipamide; polystyrene, styrene-butadiene block copolymers, styrene-acrylonitrile copolymers, styrene-butadiene-acrylonitrile copolymers Styrene-based copolymers such as coalesced (ABS resin); vinyl chloride-based copolymers such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymers; acrylic-based copolymers such as polymethylmethacrylate and methylmethacrylate / ethylacrylate copolymers. Examples thereof include copolymers; polycarbonate, cellulose-based resins; acetyl cellulose, cellulose acetyl propionate, cellulose acetate butyrate, and regenerated cellulose such as cellophane, but polyethylene terephthalate can be preferably used.
The thermoplastic resin may contain one or more additives such as pigments, antioxidants, antistatic agents, ultraviolet absorbers, and lubricants, if desired.
　紙製基材としては、所望の剛性等に応じて任意の紙を使用することができる。例えば、上質紙、模造紙、アート紙、コート紙、純白ロール紙、クラフト紙、耐水性を高めたラベル用紙、コップ原紙、カード紙、アイボリー紙、マニラボールなどの板紙、ミルクカートン原紙、カップ原紙、合成紙、クレイコート紙、耐水紙、耐酸紙等の公知の紙を使用することができる。
　紙製基材の厚みは、１５０～４００μｍ以下の範囲にあることが好ましく、また紙製基材の坪量は、１５０～３５０ｇ／ｍ２の範囲にあることが好ましい。
　紙製基材としては、抄紙成形、コーティング成形、打ち抜き成形、スリット成形、ラミネート成形、接合成形、シール成形、カーリング成形、プレス成形等の手段で製造された、抄紙状、シート状、カップ状、トレイ状、カートン状、パウチ状、箱状等の成形体を例示できる。 As the paper base material, any paper can be used depending on the desired rigidity and the like. For example, high-quality paper, imitation paper, art paper, coated paper, pure white roll paper, kraft paper, water-resistant label paper, cup base paper, card paper, ivory paper, Manila ball paperboard, milk carton base paper, cup base paper. , Synthetic paper, clay coated paper, water resistant paper, acid resistant paper and other known papers can be used.
The thickness of the paper base material is preferably in the range of 150 to 400 μm or less, and the basis weight of the paper base material is preferably in the range of 150 to 350 g / m 2 .
Paper base materials include paper-making, sheet-shaped, cup-shaped, manufactured by means such as papermaking, coating molding, punching, slit molding, laminating molding, joining molding, seal molding, curling molding, and press molding. Examples thereof include tray-shaped, carton-shaped, pouch-shaped, and box-shaped molded bodies.
　本発明の成形体を含む積層体においては、上記基材及び成形体から成る層以外に、必要により他の層を形成することもできる。
　セルロースナノクリスタル及び多価カチオン樹脂の混合物から成る層は、高湿度条件下でのガスバリア性の低下が抑制されているが、オレフィン樹脂、ポリエステル樹脂、エポキシ樹脂とポリアミン樹脂の硬化反応物等の従来公知の耐湿性樹脂から成る層を更に形成することが望ましい。 In the laminated body including the molded product of the present invention, other layers may be formed if necessary, in addition to the layer composed of the above-mentioned base material and the molded product.
The layer composed of a mixture of cellulose nanocrystals and polyvalent cation resin is suppressed from being deteriorated in gas barrier property under high humidity conditions, but conventional ones such as olefin resin, polyester resin, and curing reaction product of epoxy resin and polyamine resin are used. It is desirable to further form a layer made of a known moisture resistant resin.
（成形体の製造方法）
　本発明の成形体は、基材上に、多価カチオン樹脂含有溶液を塗工・乾燥し、多価カチオン樹脂から成る層を形成する工程、該多価カチオン樹脂から成る層上に、本発明のセルロースナノクリスタル含有コーティング液を塗工・乾燥することにより、多価カチオン樹脂及びセルロースナノクリスタルが特有の混合状態で混合された混合物から成る層を有する成形体として製造することができる。 (Manufacturing method of molded product)
The molded product of the present invention is a step of applying and drying a polyvalent cationic resin-containing solution on a base material to form a layer made of a polyvalent cationic resin, and the present invention is placed on the layer made of the polyvalent cationic resin. By coating and drying the cellulose nanocrystal-containing coating solution of the above, it can be produced as a molded product having a layer composed of a mixture of a polyvalent cationic resin and a cellulose nanocrystal mixed in a unique mixed state.
［多価カチオン樹脂含有溶液の塗工・乾燥］
　多価カチオン樹脂含有溶液は、多価カチオン樹脂を固形分基準で０．０１～３０質量％、特に０．１～１０質量％の量で含有する溶液であることが好ましい。上記範囲よりも多価カチオン樹脂の量が少ない場合には、上記範囲にある場合に比して、ガスバリア性及び界面剥離強度の向上を図ることができず、一方上記範囲よりも多価カチオン樹脂の量が多くてもガスバリア性及び界面剥離強度の更なる向上は得られず経済性に劣ると共に、塗工性や製膜性にも劣るおそれがある。
　また多価カチオン樹脂含有溶液に用いる溶媒としては、水、メタノール，エタノール，イソプロパノール等のアルコール、２－ブタノン、アセトン等のケトン、トルエン等の芳香族系溶剤、及びこれらと水との混合溶媒であってもよい。
　また多価カチオン樹脂含有溶液には、必要に応じて、充填剤、着色剤、紫外線吸収剤、帯電防止剤、耐水化剤、粘土鉱物、架橋剤、金属塩、コロイダルシリカ、アルミナゾル、酸化チタン等、公知の添加剤を配合することができる。 [Coating and drying of multivalent cationic resin-containing solution]
The polyvalent cationic resin-containing solution is preferably a solution containing the polyvalent cationic resin in an amount of 0.01 to 30% by mass, particularly 0.1 to 10% by mass based on the solid content. When the amount of the polyvalent cationic resin is smaller than the above range, the gas barrier property and the interfacial peel strength cannot be improved as compared with the case of the above range, while the polyvalent cationic resin is more than the above range. Even if the amount of the resin is large, the gas barrier property and the interfacial peeling strength cannot be further improved, which is inferior in economic efficiency and may be inferior in coatability and film forming property.
The solvent used for the polyvalent cationic resin-containing solution includes water, alcohols such as methanol, ethanol and isopropanol, ketones such as 2-butanone and acetone, aromatic solvents such as toluene, and mixed solvents of these and water. There may be.
In addition, the polyvalent cationic resin-containing solution contains, if necessary, fillers, colorants, ultraviolet absorbers, antistatic agents, water resistant agents, clay minerals, cross-linking agents, metal salts, colloidal silica, alumina sol, titanium oxide, etc. , Known additives can be blended.
　多価カチオン樹脂含有溶液は、セルロースナノクリスタル含有コーティング液から形成される層中のセルロースナノクリスタル量（固形分）を基準に、多価カチオン樹脂含有溶液の濃度によって塗工量が決定される。すなわち、前述したとおり、セルロースナノクリスタル（固形分）を１ｍ２当たり１．０ｇの量で含有する場合に、多価カチオン樹脂が１ｍ２当たり０．０１～２．０ｇの量で含有されるように、塗工することが好ましい。上記範囲よりも多価カチオン樹脂の量が少ない場合には、上記範囲にある場合に比して、ポリエステル樹脂などの疎水性の基材に対する界面剥離強度の向上を図ることができず、その一方、上記範囲よりも多価カチオン樹脂の量が多い場合には、上記範囲にある場合に比して、成形体のガスバリア性の向上が得られないおそれがある。
　塗布方法としては、これに限定されないが、例えばスプレー塗装、浸漬、或いはバーコーター、ロールコーター、グラビアコーター等により塗布することが可能である。また塗膜の乾燥方法としては、温度５～２００℃で０．１秒～２４時間の条件で乾燥することが好ましい。また乾燥処理は、オーブン乾燥、赤外線加熱、高周波加熱等により行うことができるが、自然乾燥であってもよい。 The coating amount of the polyvalent cationic resin-containing solution is determined by the concentration of the polyvalent cationic resin-containing solution based on the amount of cellulose nanocrystals (solid content) in the layer formed from the cellulose nanocrystal-containing coating liquid. That is, as described above, when the cellulose nanocrystal (solid content) is contained in an amount of 1.0 g per 1 m 2 , the multivalent cationic resin is contained in an amount of 0.01 to 2.0 g per 1 m 2. It is preferable to apply the coating. When the amount of the polyvalent cationic resin is smaller than the above range, it is not possible to improve the interfacial peeling strength against a hydrophobic substrate such as a polyester resin as compared with the case where the amount is in the above range. When the amount of the polyvalent cationic resin is larger than the above range, the gas barrier property of the molded product may not be improved as compared with the case where the amount is in the above range.
The coating method is not limited to this, and for example, spray coating, dipping, or coating by a bar coater, a roll coater, a gravure coater, or the like can be used. Further, as a method for drying the coating film, it is preferable to dry the coating film at a temperature of 5 to 200 ° C. for 0.1 seconds to 24 hours. The drying treatment can be performed by oven drying, infrared heating, high frequency heating, or the like, but may be natural drying.
［セルロースナノクリスタル含有コーティング液の塗工・乾燥］
　前述した本発明のセルロースナノクリスタル含有コーティング液は、セルロースナノクリスタル（固形分）が１ｍ２当たり０．１～３．０ｇとなるように塗工することが好ましい。
　セルロースナノクリスタル含有コーティング液の塗布方法及び乾燥方法は、多価カチオン含有溶液の塗布方法及び乾燥方法と同様に行うことができるが、温度５～２００℃で０．１秒～２４時間の条件で乾燥することが好ましい。 [Coating and drying of cellulose nanocrystal-containing coating liquid]
The cellulose nanocrystal-containing coating liquid of the present invention described above is preferably coated so that the cellulose nanocrystals (solid content) are 0.1 to 3.0 g per 1 m 2.
The method for applying and drying the cellulose nanocrystal-containing coating solution can be the same as the method for applying and drying the polyvalent cation-containing solution, but at a temperature of 5 to 200 ° C. for 0.1 seconds to 24 hours. It is preferable to dry.
　以下に本発明の実施例を説明する。なお、以下の実施例は本発明の一例であり、本発明はこれらの実施例には限定されない。各項目の測定方法は、次の通りである。 An embodiment of the present invention will be described below. The following examples are examples of the present invention, and the present invention is not limited to these examples. The measurement method for each item is as follows.
＜アニオン性官能基量＞
　ナノセルロース含有分散液を秤量し、イオン交換水を加えて０．０５～０．３質量％のナノセルロース含有分散液１００ｍｌを調製した。陽イオン交換樹脂を０．１ｇ加えて攪拌処理した。その後、ろ過を行い陽イオン交換樹脂とナノセルロース分散液を分離した。陽イオン交換後の分散液に対して電位差自動滴定装置（京都電子社製）を用いて０．０５Ｍ水酸化ナトリウム溶液を滴下し、ナノセルロース含有分散液が示す電気伝導度の変化を計測した。得られた伝導度曲線からアニオン性官能基の中和の為に消費された水酸化ナトリウム滴定量を求め、下記式を用いてアニオン性官能基量（ｍｍｏｌ／ｇ）を算出した。
　　アニオン性官能基量（ｍｍｏｌ／ｇ）＝アニオン性官能基の中和の為に消費した水酸化ナトリウム滴定量（ｍｌ）×前記水酸化ナトリウム濃度（ｍｍｏｌ／ｍｌ）÷ナノセルロースの固形質量（ｇ） <Amount of anionic functional groups>
The nanocellulose-containing dispersion was weighed, and ion-exchanged water was added to prepare 100 ml of a nanocellulose-containing dispersion of 0.05 to 0.3% by mass. 0.1 g of a cation exchange resin was added and the mixture was stirred. Then, filtration was performed to separate the cation exchange resin and the nanocellulose dispersion. A 0.05 M sodium hydroxide solution was added dropwise to the dispersion after cation exchange using an automatic potential difference titrator (manufactured by Kyoto Electronics Co., Ltd.), and the change in electrical conductivity exhibited by the nanocellulose-containing dispersion was measured. From the obtained conductivity curve, the amount of sodium hydroxide droplets consumed for neutralizing the anionic functional groups was determined, and the amount of anionic functional groups (mmol / g) was calculated using the following formula.
Amount of anionic functional group (mmol / g) = Quantitative amount of sodium hydroxide droplets consumed for neutralization of anionic functional group (ml) × sodium hydroxide concentration (mmol / ml) ÷ solid mass of nanocellulose (g) )
＜可視光線透過率＞
　分光光度計（ＵＶ－３１００ＰＣ、島津製作所）を用い、セルロースナノクリスタルが固形分２質量％の水分散液にしたときの６００ｎｍにおける可視光線透過率（％Ｔ）を求めた。 <Visible light transmittance>
Using a spectrophotometer (UV-3100PC, Shimadzu Corporation), the visible light transmittance (% T) at 600 nm when the cellulose nanocrystals were made into an aqueous dispersion having a solid content of 2% by mass was determined.
＜粒度分布＞
　レーザ回折式粒度分布測定装置（ＳＡＬＤ－３１００、島津製作所）を用い、セルロースナノクリスタルが固形分２質量％の水分散液を使って平均粒径、メディアン径、モード径を求めた。装置の光源は半導体レーザ、波長は６９０ｎｍである。吸光度は０．０１５以下で屈折率は１．５５での測定結果を解析に用いた。 <Particle size distribution>
Using a laser diffraction type particle size distribution measuring device (SALD-3100, Shimadzu Corporation), the average particle size, median diameter, and mode diameter were determined using an aqueous dispersion containing 2% by mass of cellulose nanocrystals. The light source of the device is a semiconductor laser, and the wavelength is 690 nm. The measurement results at an absorbance of 0.015 or less and a refractive index of 1.55 were used for the analysis.
＜酸素透過度＞
　酸素透過量測定装置（ＯＸ－ＴＲＡＮ２／２２、モコン）を用いて、２３℃湿度５０％ＲＨの条件で成形体の酸素透過度（ｃｃ／ｍ２・ｄａｙ・ａｔｍ）を測定した。 <Oxygen permeability>
Oxygen permeability measuring apparatus (OX-TRAN2 / 22, remote control) was used to measure the oxygen permeability of the shaped body (cc / m 2 · day · atm) under the conditions of 23 ° C. and humidity 50% RH.
（実施例１）
　パルプを６４質量％の硫酸で分解処理することによってセルロースナノクリスタルを調製した。前記セルロースナノクリスタルは乾燥固化させず超遠心分離機にて濃縮と洗浄を行うことでネバードライ処理したセルロースナノクリスタルを調製し、最終的にセルロースナノクリスタルが固形分２質量％になるようにイオン交換水に加え、超音波分散機にて１０分処理することでセルロースナノクリスタル分散液を調製した。 (Example 1)
Cellulose nanocrystals were prepared by decomposing pulp with 64% by weight sulfuric acid. The cellulose nanocrystals are not dried and solidified, but are concentrated and washed in an ultracentrifuge to prepare cellulose nanocrystals that have been never dried, and finally the cellulose nanocrystals are ionized so that the solid content is 2% by mass. A cellulose nanocrystal dispersion was prepared by treating with an ultrasonic disperser for 10 minutes in addition to the exchanged water.
（実施例２）
　実施例１と同様にネバードライ処理したセルロースナノクリスタルを調製し、最終的にセルロースナノクリスタルが固形分２質量％になるようにイオン交換水に加え、超高圧ホモジナイザーにて１０分処理することでセルロースナノクリスタル分散液を調製した。 (Example 2)
A cellulose nanocrystal that has been never-dried in the same manner as in Example 1 is prepared, finally added to ion-exchanged water so that the cellulose nanocrystal has a solid content of 2% by mass, and treated with an ultra-high pressure homogenizer for 10 minutes. A cellulose nanocrystal dispersion was prepared.
（実施例３）
　実施例１と同様にネバードライ処理したセルロースナノクリスタルを調製した。セルロースナノクリスタルが１０ｇ（固形量）の水分散液に対し、ＴＥＭＰＯ触媒（Ｓｉｇｍａ　Ａｌｄｒｉｃｈ社製）０．８ｍｍｏｌと臭化ナトリウム１２．１ｍｍｏｌを添加し、イオン交換水を加えて１Ｌにメスアップし、均一に分散するまで攪拌した。その後５ｍｍｏｌの次亜塩素酸ナトリウムを添加し、酸化反応を開始した。反応中は０．５Ｎ水酸化ナトリウム水溶液でｐＨ１０．０から１０．５に系内のｐＨを保持し、３０℃で４時間攪拌しながら親水化処理を行った。親水化処理したセルロースナノクリスタルはイオン交換水を加えながら超遠心分離機（５００００ｒｐｍ、１０分）を用いてｐＨが８になるまで洗浄した。その後透析膜（スペクトラム社製・分画分子量３５００～５０００Ｄ）の内部に入れてイオン交換水中で静置して不純物等を除去し、セルロースナノクリスタルを調製した。前記の洗浄したセルロースナノクリスタル分散液にイオン交換水を加え、超音波分散機にて分散処理することで、セルロースナノクリスタルを工程において固化させずにＴＥＭＰＯ触媒によって酸化したセルロースナノクリスタルの固形量が２質量％のセルロースナノクリスタル分散液を調製した。 (Example 3)
Never-dried cellulose nanocrystals were prepared in the same manner as in Example 1. To an aqueous dispersion containing 10 g (solid content) of cellulose nanocrystals, 0.8 mmol of TEMPO catalyst (manufactured by Sigma-Aldrich) and 12.1 mmol of sodium bromide were added, and ion-exchanged water was added to increase the volume to 1 L. Stirred until uniformly dispersed. Then, 5 mmol of sodium hypochlorite was added to start the oxidation reaction. During the reaction, the pH in the system was maintained from 10.0 to 10.5 with a 0.5 N aqueous sodium hydroxide solution, and the hydrophilization treatment was carried out with stirring at 30 ° C. for 4 hours. The hydrophilized cellulose nanocrystals were washed with an ultracentrifugator (50,000 rpm, 10 minutes) while adding ion-exchanged water until the pH reached 8. Then, it was placed inside a dialysis membrane (manufactured by Spectrum Co., Ltd., molecular weight cut off of 3500 to 5000D) and allowed to stand in ion-exchanged water to remove impurities and the like to prepare cellulose nanocrystals. By adding ion-exchanged water to the washed cellulose nanocrystal dispersion and dispersing it with an ultrasonic disperser, the solid amount of cellulose nanocrystals oxidized by the TEMPO catalyst without solidifying the cellulose nanocrystals in the process can be obtained. A 2% by mass cellulose nanocrystal dispersion was prepared.
（比較例１）
　パルプを６４質量％の硫酸で分解処理後に洗浄し、乾燥固化させることで乾燥固化させたセルロースナノクリスタルを調製した。前記セルロースナノクリスタル１ｇ（固形量）をイオン交換水に加え、超音波分散機にて１０分間分散処理を行う事で、セルロースナノクリスタルの固形量が２質量％のセルロースナノクリスタル分散液を得た。 (Comparative Example 1)
The pulp was decomposed with 64% by mass of sulfuric acid, washed, and dried and solidified to prepare cellulose nanocrystals that were dried and solidified. By adding 1 g (solid amount) of the cellulose nanocrystals to ion-exchanged water and performing a dispersion treatment with an ultrasonic disperser for 10 minutes, a cellulose nanocrystal dispersion having a solid amount of 2% by mass of the cellulose nanocrystals was obtained. ..
（比較例２）
　比較例１と同様に乾燥固化させたセルロースナノクリスタルを調製した。前記セルロースナノクリスタルについて、実施例３と同様にＴＥＭＰＯ触媒によって酸化を行い、セルロースナノクリスタルの固形量が２質量％のセルロースナノクリスタル分散液を調製した。 (Comparative Example 2)
Cellulose nanocrystals dried and solidified were prepared in the same manner as in Comparative Example 1. The cellulose nanocrystals were oxidized with a TEMPO catalyst in the same manner as in Example 3 to prepare a cellulose nanocrystal dispersion having a solid content of 2% by mass of the cellulose nanocrystals.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
＜パルスＮＭＲ＞
　上述した実施例１及び比較例１で得られたセルロースナノクリスタル分散液を濃縮して固形量５質量％にし、パルスＮＭＲのソリッドエコー法で測定された３０℃におけるセルロースナノファイバー分散液の自由誘導減衰（Ｍ（ｔ））を、下記条件で測定した。
　　測定装置：Ｂｒｕｋｅｒ製　ＴＤ－ＮＭＲ　ｔｈｅ　ｍｉｎｉｓｐｅｃ　ｍｑ２０
　　サンプル量：約２００ｍｇ
　　観測核：１Ｈ
　　測定：Ｔ２
　　測定法：ソリッドエコー法
　　９０°パルス幅：２．２μｓｅｃ
　　積算回数：３２回
　　測定温度：３０℃（装置温度が設定温度に達してから１５分後にサンプル内部温度が測定温度になるように装置温度を調整し、測定を開始した）
　　繰り返し時間：８ｓｅｃ <Pulse NMR>
The cellulose nanocrystal dispersions obtained in Example 1 and Comparative Example 1 described above were concentrated to a solid content of 5% by mass, and free induction of the cellulose nanofiber dispersion at 30 ° C. measured by the solid echo method of pulse NMR. The decay (M (t)) was measured under the following conditions.
Measuring device: Bruker TD-NMR the minispec mq20
Sample amount: Approximately 200 mg
Observation nucleus: 1H
Measurement: T2
Measurement method: Solid echo method 90 ° Pulse width: 2.2 μsec
Number of integrations: 32 times Measurement temperature: 30 ° C (The device temperature was adjusted so that the sample internal temperature reached the measurement temperature 15 minutes after the device temperature reached the set temperature, and measurement was started).
Repeat time: 8 sec
　また、前述した式（５）を用いて、解析ソフト（ＴＤＮＭＲ－Ａ）によりフィッティングを行い、前述した成分（α）に近似して解析した。また前述した式（６）、式（７）を用いて、前述した成分（α）、成分（β）、成分（γ）の２成分以上で解析し、解析ソフト上でエラーが返される場合は２成分以上が存在しないことを確認した。 Further, using the above-mentioned formula (5), fitting was performed by analysis software (TDNMR-A), and the analysis was performed by approximating the above-mentioned component (α). If two or more of the above-mentioned components (α), (β), and (γ) are analyzed using the above-mentioned equations (6) and (7) and an error is returned on the analysis software. It was confirmed that two or more components did not exist.
　実施例１のセルロースナノクリスタル分散液においては、成分（α）のプロトン比率１００（％）、成分（α）のＴ２緩和時間１５７９（μｓｅｃ）となり、１成分での数値の解析結果が得られた。これによりネバードライ処理によるセルロースナノクリスタルのみが溶媒中に分散し、１成分の均一な運動性を有していることを示しており、セルロースナノクリスタルが分散液中で優れた均質性を有していることがわかる。
　また比較例１のセルロースナノクリスタル分散液においては、成分（α）のプロトン比率８６．７（％）、成分（α）のＴ２緩和時間１５１９（μｓｅｃ）、及び成分（β）のプロトン比率１３．６（％）、成分（β）のＴ２緩和時間７７２３（μｓｅｃ）となり、成分（α）及び成分（β）の２成分での数値の解析結果が得られた。この結果から、溶媒中には、乾燥固化を経たセルロースナノクリスタルと、凝集化して分散されたセルロースナノクリスタルの２成分が存在し、２成分で均一でない運動性を有し、分散液中でのセルロースナノクリスタルの不均質性がわかる。 In the cellulose nanocrystal dispersion of Example 1, the proton ratio of the component (α) was 100 (%) and the T2 relaxation time of the component (α) was 1579 (μsec), and the numerical analysis results of one component were obtained. .. This indicates that only the cellulose nanocrystals obtained by the never-dry treatment are dispersed in the solvent and have uniform motility of one component, and the cellulose nanocrystals have excellent homogeneity in the dispersion liquid. You can see that.
Further, in the cellulose nanocrystal dispersion liquid of Comparative Example 1, the proton ratio of the component (α) was 86.7 (%), the T2 relaxation time of the component (α) was 1519 (μsec), and the proton ratio of the component (β) was 13. The T2 relaxation time of 6 (%) and the component (β) was 7723 (μsec), and the numerical analysis results of the two components of the component (α) and the component (β) were obtained. From this result, there are two components in the solvent, cellulose nanocrystals that have undergone dry solidification and cellulose nanocrystals that have been aggregated and dispersed, and the two components have non-uniform motility and are contained in the dispersion liquid. The inhomogeneity of cellulose nanocrystals can be seen.
＜クライオＳＥＭ＞
　実施例１及び比較例１で得られたセルロースナノクリスタル分散液を濃縮して固形量５質量％にし、分取して－１６０℃で凍結破断し、－８０℃にして水を昇華させ、冷却状態を保持したまま破断面についてＦＩＢによる断面調整およびＦＥ－ＳＥＭ観察を行った。ＳＥＭ観察写真を図２及び図３に示す。
　　装置：ＦＥＩ，　Ｈｅｌｉｏｓ　ＮａｎｏＬａｂ　６００，　Ｈｅｌｉｏｓ　Ｇ４　ＵＸ
　　加速電圧：ＦＩＢ３０ｋＶ，　ＳＥＭ　１～２　ｋＶ
　　観察像：反射電子像
　　加工設定温度：－１６０℃
　　観察設定温度：－８０℃ <Cryo SEM>
The cellulose nanocrystal dispersions obtained in Example 1 and Comparative Example 1 were concentrated to a solid content of 5% by mass, separated, frozen and broken at −160 ° C., sublimated to −80 ° C., and cooled. The fracture surface was adjusted by FIB and FE-SEM observation was performed while maintaining the state. SEM observation photographs are shown in FIGS. 2 and 3.
Equipment: FEI, Helios NanoLab 600, Helios G4 UX
Acceleration voltage: FIB30 kV, SEM 1-2 kV
Observation image: Reflected electron image Processing set temperature: -160 ° C
Observation set temperature: -80 ° C
　図２から明らかなように、実施例１のセルロースナノクリスタル分散液では、ネバードライ処理したセルロースナノクリスタルは微細にかつ均質に分散されていることが観察された。
　また図３から明らかなように、比較例１のセルロースナノクリスタル分散液は、凝集化したセルロースナノクリスタルが存在し均質な分散ではないことが観察された。 As is clear from FIG. 2, in the cellulose nanocrystal dispersion liquid of Example 1, it was observed that the cellulose nanocrystals treated with never dry were finely and uniformly dispersed.
Further, as is clear from FIG. 3, it was observed that the cellulose nanocrystal dispersion liquid of Comparative Example 1 had aggregated cellulose nanocrystals and was not uniformly dispersed.
（実施例４）
＜セルロースナノクリスタル含有コーティング液の調製＞
　実施例１のセルロースナノクリスタル分散液を用い、セルロースナノクリスタルの固形量が１質量％になるようにイオン交換水で希釈し、無水クエン酸、硫酸、合成マイカ（親水性膨潤性雲母、片倉コープアグリ社製）、ポリビニルアルコール（完全ケン化型、クラレ社製）をセルロースナノクリスタル１００質量部（固形分）に対して１０質量部、２質量部、３０質量部及び３０質量部を添加して攪拌を行い、ｐＨが３のセルロースナノクリスタル含有コーティング液を調製した。 (Example 4)
<Preparation of cellulose nanocrystal-containing coating liquid>
Using the cellulose nanocrystal dispersion of Example 1, dilute with ion-exchanged water so that the solid content of the cellulose nanocrystals is 1% by mass, anhydrous citric acid, sulfuric acid, synthetic mica (hydrophilic swelling mica, Katakura Corp.). Add 10 parts by mass, 2 parts by mass, 30 parts by mass and 30 parts by mass of cellulose nanocrystals (manufactured by Agri) and polyvinyl alcohol (completely saponified type, manufactured by Kuraray) to 100 parts by mass (solid content) of cellulose nanocrystals. Stirring was performed to prepare a cellulose nanocrystal-containing coating liquid having a pH of 3.
＜多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体＞
　以下の手順により多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体を作製した。
　コロナ処理された２軸延伸ＰＥＴフィルム（ルミラーＰ６０，１２μｍ，東レ株式会社製）基材にバーコーターを用いてポリエチレンイミン（ＰＥＩ）（エポミン，Ｐ－１０００，株式会社日本触媒製）を塗工量が固形量として０．６ｇ／ｍ２になるように塗工した。熱風乾燥器（ＭＳＯ－ＴＰ，ＡＤＶＡＮＴＥＣ社製）により５０℃で１０分乾燥して固形化した後、バーコーターを用いて前記方法で製造された１質量％のセルロースナノクリスタル含有コーティング液を、固形量として１．０ｇ／ｍ２の塗工量で塗工し、室温で一晩風乾することにより、２軸延伸ＰＥＴフィルム上に多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体を調製した。 <A molded product in which a layer containing a multivalent cationic resin and cellulose nanocrystals is formed>
A molded product was prepared by forming a layer containing a polyvalent cationic resin and cellulose nanocrystals by the following procedure.
Corona-treated biaxially stretched PET film (Lumira P60, 12 μm, manufactured by Toray Industries, Inc.) Polyethylene imine (PEI) (Epomin, P-1000, manufactured by Nippon Catalyst Co., Ltd.) is applied to the base material using a bar coater. Was applied so that the solid content was 0.6 g / m 2. After drying for 10 minutes at 50 ° C. for 10 minutes with a hot air dryer (MSO-TP, manufactured by ADVANTEC) to solidify, the 1% by mass cellulose nanocrystal-containing coating liquid produced by the above method using a bar coater is solidified. A layer containing a polyvalent cation resin and cellulose nanocrystals is formed on a biaxially stretched PET film by coating with a coating amount of 1.0 g / m 2 and air-drying at room temperature overnight. A molded product was prepared.
（実施例５）
　実施例２のセルロースナノクリスタル分散液を使用した以外は、実施例４と同様にしてセルロースナノクリスタル含有コーティング液を調製し、次いで、多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体を調製した。 (Example 5)
A cellulose nanocrystal-containing coating liquid was prepared in the same manner as in Example 4 except that the cellulose nanocrystal dispersion liquid of Example 2 was used, and then a layer containing a polyvalent cationic resin and a cellulose nanocrystal was formed. A molded product was prepared.
（比較例３）
　比較例１のセルロースナノクリスタル分散液を使用した以外は、実施例４と同様にしてセルロースナノクリスタル含有コーティング液を調製し、次いで、多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体を調製した。 (Comparative Example 3)
A cellulose nanocrystal-containing coating liquid was prepared in the same manner as in Example 4 except that the cellulose nanocrystal dispersion liquid of Comparative Example 1 was used, and then a layer containing a polyvalent cationic resin and a cellulose nanocrystal was formed. A molded product was prepared.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　本発明のセルロースナノクリスタル分散液は、塗工性及び取扱い性に優れ、ガスバリア性及び透明性に優れた塗膜を形成することが可能であり、ガスバリア性能を付与可能なコーティング剤として使用される。また固形化されたセルロースナノクリスタルを分散させた分散液よりも分散性に優れており、多価カチオン樹脂や架橋剤との混合物から成る成形体とすることで、ガスバリア性フィルムとして、或いは熱可塑性樹脂等から成る疎水性の基材との界面剥離強度も向上されていることから、ガスバリア性積層体として好適に使用される。 The cellulose nanocrystal dispersion liquid of the present invention is excellent in coatability and handleability, can form a coating film having excellent gas barrier property and transparency, and is used as a coating agent capable of imparting gas barrier performance. .. In addition, it has better dispersibility than the dispersion liquid in which solidified cellulose nanocrystals are dispersed, and by forming a molded product composed of a mixture of a polyvalent cationic resin and a cross-linking agent, it can be used as a gas barrier film or thermoplastic. Since the interfacial peeling strength with a hydrophobic base material made of resin or the like is also improved, it is suitably used as a gas barrier laminate.

Claims (12)

  1. 　硫酸処理由来の硫酸基及び／又はスルホ基、及び親水化処理由来のアニオン性官能基を含有するセルロースナノクリスタル分散液であって、前記セルロースナノクリスタルの固形分量が２質量％の水分散における６００ｎｍでの可視光線透過率が４５％Ｔ以上であることを特徴とするセルロースナノクリスタル分散液。 A cellulose nanocrystal dispersion containing a sulfate group and / or a sulfo group derived from a sulfuric acid treatment and an anionic functional group derived from a hydrophilic treatment, wherein the solid content of the cellulose nanocrystals is 600 nm in an aqueous dispersion of 2% by mass. A cellulose nanocrystal dispersion liquid having a visible light transmittance of 45% T or more.
  2. 　前記セルロースナノクリスタル分散液のレーザ回折式粒度分布測定装置によるセルロースナノクリスタルの平均粒径が１０．１μｍ以下且つメディアン径が１０．６μｍ以下且つモード径が１０．９μｍ以下である請求項１記載のセルロースナノクリスタル分散液。 The first aspect of claim 1, wherein the average particle size of the cellulose nanocrystals by the laser diffraction type particle size distribution measuring device of the cellulose nanocrystal dispersion is 10.1 μm or less, the median diameter is 10.6 μm or less, and the mode diameter is 10.9 μm or less. Cellulose nanocrystal dispersion.
  3. 　前記硫酸基及び／又はスルホ基、及びアニオン性官能基の総量が０．１７ｍｍｏｌ／ｇより多く且つ４．０ｍｍｏｌ／ｇ以下である請求項１記載のセルロースナノクリスタル分散液。 The cellulose nanocrystal dispersion according to claim 1, wherein the total amount of the sulfate group and / or the sulfo group and the anionic functional group is more than 0.17 mmol / g and 4.0 mmol / g or less.
  4. 　前記セルロースナノクリスタルの結晶化度が６０％以上であり、且つ繊維径が５０ｎｍ以下でアスペクト比が５～５０である請求項１～３の何れかに記載のセルロースナノクリスタル分散液。 The cellulose nanocrystal dispersion according to any one of claims 1 to 3, wherein the cellulose nanocrystal has a crystallinity of 60% or more, a fiber diameter of 50 nm or less, and an aspect ratio of 5 to 50.
  5. 　前記アニオン性官能基が、硫酸基、スルホ基、リン酸基、カルボキシル基のうちの少なくとも１つである請求項１～４の何れかに記載のセルロースナノクリスタル分散液。 The cellulose nanocrystal dispersion according to any one of claims 1 to 4, wherein the anionic functional group is at least one of a sulfate group, a sulfo group, a phosphoric acid group, and a carboxyl group.
  6. 　前記親水化処理が、ネバードライ処理、又はネバードライ処理と、カルボジイミド、硫酸、三酸化硫黄－ピリジン錯体、リン酸－尿素、ＴＥＭＰＯ触媒、酸化剤の何れかを用いた処理との組み合わせである請求項１～５の何れかに記載のセルロースナノクリスタル分散液。 A claim that the hydrophilization treatment is a combination of a never-dry treatment or a never-dry treatment and a treatment using any one of carbodiimide, sulfuric acid, sulfur trioxide-pyridine complex, phosphoric acid-urea, TEMPO catalyst, and an oxidizing agent. Item 2. The cellulose nanocrystal dispersion according to any one of Items 1 to 5.
  7. 　請求項１～６の何れかに記載のセルロースナノクリスタル分散液、水溶性高分子、無機層状化合物及び多価カルボン酸を含有することを特徴とするセルロースナノクリスタル含有コーティング液。 A cellulose nanocrystal-containing coating liquid containing the cellulose nanocrystal dispersion liquid according to any one of claims 1 to 6, a water-soluble polymer, an inorganic layered compound, and a polyvalent carboxylic acid.
  8. 　前記水溶性高分子がポリビニルアルコールであり、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で含有する請求項７記載のセルロースナノクリスタル含有コーティング液。 The cellulose nanocrystal-containing coating liquid according to claim 7, wherein the water-soluble polymer is polyvinyl alcohol and is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content).
  9. 　前記無機層状化合物がマイカであり、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で含有する請求項７又は８記載のセルロースナノクリスタル含有コーティング液。 The cellulose nanocrystal-containing coating liquid according to claim 7 or 8, wherein the inorganic layered compound is mica and is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of cellulose nanocrystals (solid content).
  10. 　前記多価カルボン酸がクエン酸であり、セルロースナノクリスタル（固形分）１００質量部に対して０．１～５０質量部の量で含有する請求項７～９の何れかに記載のセルロースナノクリスタル含有コーティング液。 The cellulose nanocrystal according to any one of claims 7 to 9, wherein the polyunsaturated carboxylic acid is citric acid and is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the cellulose nanocrystal (solid content). Containing coating liquid.
  11. 　基材上に、多価カチオン樹脂及びセルロースナノクリスタルを含有する層が形成されて成る成形体であって、前記セルロースナノクリスタル（固形分）を１．０ｇ／ｍ２の量で含有するときの酸素透過度（２３℃５０％ＲＨ）が３．８ｃｃ／ｍ２・ｄａｙ・ａｔｍ未満であることを特徴とする成形体。 A molded product in which a layer containing a polyvalent cationic resin and a cellulose nanocrystal is formed on a base material, and the cellulose nanocrystal (solid content) is contained in an amount of 1.0 g / m 2. A molded product having an oxygen permeability (23 ° C., 50% RH) of less than 3.8 cc / m 2, day, atm.
  12. 　前記多価カチオン樹脂が、ポリエチレンイミンである請求項１１記載の成形体。 The molded product according to claim 11, wherein the polyvalent cationic resin is polyethyleneimine.
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