JP5665487B2 - Membrane and method for producing the same - Google Patents

Description

  The present invention relates to a film-like body containing fine cellulose fibers and a method for producing the same.

  In recent years, technologies that have a low environmental impact have come to the spotlight. Under such technical background, materials using cellulose fibers, which are biomass that exists in large amounts in nature, have attracted attention, and various improved technologies have been proposed in this regard. ing. For example, the present applicant has previously proposed a gas barrier material containing cellulose fibers having an average fiber diameter of 200 nm or less and having a carboxyl group content of 0.1 to 2 mmol / g of cellulose constituting the cellulose fibers (patent) Reference 1).

  By the way, what added the layered inorganic compound as a gas barrier film known until now is known. For example, Patent Document 2 proposes a gas barrier film in which a polyvinyl alcohol polymer composition is laminated on one side of a resin base film. This polyvinyl alcohol polymer composition contains an inorganic swellable layered compound such as montmorillonite. Patent Document 3 proposes a biodegradable gas barrier material in which a film made of a polysaccharide having a uronic acid residue is formed on one side of a polylactic acid-based or polyester-based biodegradable resin substrate. This coating contains a layered inorganic compound such as montmorillonite.

JP 2009-57552 A JP 2001-121659 A JP 2008-49606 A

  An object of the present invention is to improve a gas barrier material containing fine cellulose fibers having a nano-sized fiber diameter, and firstly, to improve water vapor barrier properties. Second, there is an improvement in oxygen barrier properties in a high humidity atmosphere.

  The present invention includes a fine cellulose fiber and a layered inorganic compound, the carboxyl group content of the cellulose constituting the fine cellulose fiber is 0.1 to 3 mmol / g, and the layered inorganic compound and the fine cellulose fiber A film-like body having a mass ratio (layered inorganic compound / cellulose fiber) of 0.01 to 100 is provided.

The present invention is also a preferred method for producing the film-like body,
A step (b) of mixing a layered inorganic compound and a dispersion of fine cellulose fibers to produce a mixed dispersion, and a step (c) of forming a coating film from the mixed dispersion and drying the coating film. The manufacturing method of the membranous body containing is provided.

  According to the present invention, a film-like body having a high barrier property against various gases such as oxygen, water vapor, carbon dioxide, carbon monoxide, nitrogen, nitrogen oxide, hydrogen, and argon gas is provided. In particular, a gas barrier material having high water vapor barrier properties or high oxygen barrier properties in a high humidity atmosphere is provided.

FIG. 1 (a) is a transmission electron microscope image of the film-like body obtained in Example 15, and FIG. 1 (b) is an enlarged image of FIG. 1 (a). 2A is a transmission electron microscope image of the film-like body obtained in Example 17, and FIG. 2B is an enlarged image of FIG. FIG. 3A is a transmission electron microscope image of the film-like body obtained in Comparative Example 1, and FIG. 3B is an enlarged image of FIG.

  Hereinafter, the present invention will be described based on preferred embodiments thereof. The film-like body of the present invention has gas barrier properties. The film-like body of the present invention may not only improve the barrier property with respect to all of the various gases described above, but may improve the barrier property only with respect to a specific gas. For example, a film-like body in which the oxygen barrier property is lowered but the water vapor barrier property is improved is a film-like body that selectively inhibits the permeation of water vapor, and falls within the scope of the present invention. The gas for which the barrier property is improved is appropriately selected depending on the application.

  In the film-like body of the present invention, the thickness is optional depending on the purpose, and for example, it can be preferably 20 to 900 nm, more preferably 50 to 700 nm, and still more preferably 100 to 500 nm. This film-like body can be used alone or can be used by being laminated on the surface of the substrate. As the substrate, for example, a two-dimensional body such as a film or a sheet, or a three-dimensional body such as a bottle or a box can be used. The area of the film-like body is not critical in the present invention, and can be appropriately set according to the specific use of the film-like body.

  The membranous body is characterized by containing specific fine cellulose fibers and a layered inorganic compound as its constituent materials. In the film-like body, the fine cellulose fibers and the layered inorganic compound are present in a uniform mixed state. The present inventors have found that the film-like body of the present invention produced using both of these as constituent materials has higher gas barrier properties than the film-like body produced by using fine cellulose fibers alone. In particular, the present inventors have found that the water vapor barrier property or the oxygen barrier property in a high humidity atmosphere is enhanced. Hereinafter, the fine cellulose fiber and the layered inorganic compound constituting the film-like body will be described.

  The fine cellulose fibers preferably have an average fiber diameter of 200 nm or less, more preferably 1 to 200 nm, still more preferably 1 to 100 nm, and still more preferably 1 to 50 nm. By using fine cellulose fibers having an average fiber diameter of 200 nm or less, voids between the cellulose fibers can be reduced, and good gas barrier properties can be obtained. The average fiber diameter is measured by the following method.

<Measurement method of average fiber diameter>
An aqueous dispersion of fine cellulose fibers having a solid content concentration of 0.001% by mass is prepared. An observation sample is obtained by dripping this dispersion liquid onto mica (mica) and drying it. Using an atomic force microscope (NanoNaVi IIe, SPA400, manufactured by SII Nano Technology, Inc., the probe uses SI-DF40Al manufactured by the same company), the fiber height of the fine cellulose fibers in the observation sample is measured. In a microscopic image in which cellulose fibers can be confirmed, five or more cellulose fibers are extracted, and the average fiber diameter is calculated from the fiber heights.

  The fine cellulose fiber used in the present invention is obtained by refining a natural cellulose fiber described later to a structural unit called microfibril. The shape of the microfibril varies depending on the raw material, but many natural cellulose fibers have a rectangular cross-sectional structure in which dozens of cellulose molecular chains are collected and crystallized. For example, microfibrils in the cell walls of higher plants have a square cross-sectional structure in which 6 × 6 cellulose molecular chains are gathered. Therefore, the height of the fine cellulose fiber obtained by the atomic force microscope image was used as the fiber diameter for convenience.

  In addition to being fine, the fine cellulose fiber is also characterized by the carboxyl group content of the cellulose constituting it. Specifically, carboxyl group content is 0.1-3 mmol / g, Preferably it is 0.4-2 mmol / g, More preferably, it is 0.6-1.8 mmol / g, More preferably, it is 0.00. 6-1.6 mmol / g.

  When the carboxyl group content is less than 0.1 mmol / g, the average fiber diameter does not become 200 nm or less even if the cellulose fiber is refined. That is, the carboxyl group content is an important factor in stably obtaining cellulose fibers having a minute fiber diameter of 200 nm or less in average fiber diameter. In the process of biosynthesis of natural cellulose, normally, nanofibers called microfibrils are first formed, and these are multi-bundled to build a high-order solid structure. Fine cellulose fibers used in the present invention are, As will be described later, this is obtained in principle, and in order to weaken the hydrogen bond between the surfaces, which is the driving force of strong cohesion between microfibrils in the naturally derived cellulose solid raw material, It is obtained by oxidizing a part and converting to a carboxyl group. Accordingly, the larger the total amount of carboxyl groups (carboxyl group content) present in cellulose, the more stable the fiber diameter can be. Further, in water, an electric repulsive force is generated, so that the tendency of the microfibrils to break apart without maintaining aggregation is increased, and the dispersion stability of the nanofibers is further increased. The carboxyl group content is measured by the following method.

<Measurement method of carboxyl group content>
Take a cellulose fiber with a dry mass of 0.5 g in a 100 ml beaker and add ion exchange water to make a total of 55 ml. The dispersion is stirred. 0.1 M hydrochloric acid is added to this dispersion to adjust the pH to 2.5-3. Using an automatic titrator (AUT-50, manufactured by Toa DKK Co., Ltd.), 0.05M aqueous sodium hydroxide solution is added dropwise to the dispersion under conditions of a waiting time of 60 seconds. The conductivity and pH values are measured every minute, and the measurement is continued until the pH is about 11 to obtain a conductivity curve. From this conductivity curve, the sodium hydroxide titration amount is obtained, and the carboxyl group content of the cellulose fiber is calculated according to the following formula.
Carboxyl group content (mmol / g) = sodium hydroxide titration (ml) × sodium hydroxide aqueous solution concentration (0.05 M) / mass of cellulose fiber (0.5 g)

  The length of the fine cellulose fiber is not particularly limited. When the fiber length is represented by an average aspect ratio (fiber length / fiber diameter), it is preferably 10 to 1000, more preferably 10 to 500, and still more preferably 100 to 350. The average aspect ratio is measured by the following method.

<Measuring method of average aspect ratio>
It calculates from the viscosity of the dispersion liquid (The density | concentration of fine cellulose fiber 0.005-0.04 mass%) prepared by adding water to a fine cellulose fiber. The viscosity of the dispersion is measured at 20 ° C. using a rheometer (MCR, DG42 (double cylinder), manufactured by PHYSICA). From the relationship between the mass concentration of the cellulose fibers in the dispersion and the specific viscosity of the dispersion with respect to water, the aspect ratio of the cellulose fibers is calculated back using the following formula (1) to obtain the average aspect ratio. Equation (1) can be derived from The Theory of Polymer Dynamics, M .; DOI and D.D. F. EDWARDS, CLARENDON PRESS · OXFORD, 1986 , p312 viscosity rigid-rod molecules according to equation (8.138), the relationship wherein the ^{Lb 2 × ρ = M / N} A, L is the fiber length, b is fiber width (The cross section of the cellulose fiber is a square), ρ is the concentration of the cellulose fiber (kg / m ³ ), M is the molecular weight, and N _A is the Avogadro number. In the viscosity formula (8.138), rigid rod-like molecule = fine cellulose fiber. In Formula (1), η _SP is the specific viscosity, π is the circumference ratio, ln is the natural logarithm, P is the aspect ratio (L / b), γ = 0.8, ρ _S is the density of the dispersion medium (kg / M ³ ), ρ ₀ represents the density of cellulose crystals (kg / m ³ ), and C represents the mass concentration of cellulose (C = ρ / ρ _S ).

  The fine cellulose fiber can be obtained, for example, by a production method including an oxidation reaction step for obtaining a reaction product fiber by oxidizing natural cellulose fiber and a refinement step for making the reaction product fiber fine. In the oxidation reaction step, first, a slurry in which natural cellulose fibers are dispersed in water is prepared. The slurry is obtained by adding about 10 to 1000 times (mass basis) of water to the natural cellulose fiber (absolute dry basis) as a raw material, and processing with a mixer or the like. Examples of natural cellulose fibers include wood pulp such as softwood pulp and hardwood pulp; cotton pulp such as cotton linter and cotton lint; non-wood pulp such as straw pulp and bagasse pulp; and bacterial cellulose. These 1 type can be used individually or in combination of 2 or more types. The natural cellulose fiber may be subjected to a treatment for increasing the surface area such as beating.

  Next, using an N-oxyl compound as an oxidation catalyst, natural cellulose fibers are oxidized in water to obtain reactant fibers. Examples of N-oxyl compounds include 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO), 4-acetamido-TEMPO, 4-carboxy-TEMPO, 4-phosphonooxy-TEMPO, and the like. Can be used. A catalytic amount is sufficient for the addition of the N-oxyl compound, and is usually in the range of 0.1 to 10% by mass relative to the natural cellulose fiber (absolute dry basis) used as a raw material.

  In the oxidation treatment of natural cellulose fiber, an oxidizing agent (for example, hypohalous acid or a salt thereof, hypohalous acid or a salt thereof, perhalogenic acid or a salt thereof, hydrogen peroxide, a perorganic acid, etc.) and a co-oxidant (For example, alkali metal bromide such as sodium bromide). As the oxidizing agent, alkali metal hypohalites such as sodium hypochlorite and sodium hypobromite are particularly preferable. The amount of the oxidizing agent used is usually in the range of about 1 to 100% by mass with respect to the natural cellulose fiber (absolute dry standard) used as a raw material. Moreover, the usage-amount of a co-oxidant is the range used as about 1-30 mass% normally with respect to the natural cellulose fiber (absolute dry reference | standard) used as a raw material.

  In the oxidation treatment of natural cellulose fibers, it is desirable to maintain the pH of the reaction solution (slurry) in the range of 9 to 12 from the viewpoint of allowing the oxidation reaction to proceed efficiently. The temperature of the oxidation treatment (the temperature of the slurry) is arbitrary at 1 to 50 ° C., but the reaction is possible at room temperature, and no temperature control is required. The reaction time is preferably 1 to 240 minutes.

  After the oxidation reaction step, a purification step is performed before the miniaturization step to remove impurities other than the reactant fibers and water contained in the slurry, such as unreacted oxidant and various by-products. Since the reaction product fibers are not normally dispersed evenly at the nanofiber unit at this stage, in the purification step, for example, a purification method in which water washing and filtration are repeated can be performed. The purification apparatus used in that case is not particularly limited. The purified reaction product fiber thus obtained is usually sent to the next step (miniaturization step) impregnated with an appropriate amount of water. However, if necessary, it may be dried into a fiber or powder form. Good.

  In the miniaturization step, the reaction product fibers that have undergone the purification step are dispersed in a solvent such as water and subjected to a miniaturization treatment. By passing through this refinement | miniaturization process, the fine fiber which has an average fiber diameter and an average aspect ratio in the said range, respectively is obtained.

  In the miniaturization treatment, the solvent as the dispersion medium is usually water, but in addition to water, an organic solvent soluble in water (alcohols, ethers, ketones, etc.) may be used depending on the purpose. These mixtures can also be suitably used. Examples of the disperser used in the miniaturization treatment include a disaggregator, a beater, a low pressure homogenizer, a high pressure homogenizer, a grinder, a cutter mill, a ball mill, a jet mill, a short shaft extruder, a twin screw extruder, an ultrasonic stirrer, and a household. Juicer mixer for use. The solid content concentration of the reactant fiber in the miniaturization treatment is preferably 50% by mass or less.

  The fine cellulose fiber obtained after the micronization step is in the form of a dispersed liquid (a liquid that is visually colorless and transparent or opaque) with a solid content adjusted as necessary, or in the form of a powder that has been dried (however, the cellulose fiber Is an agglomerated powder and does not mean cellulose particles). When making a dispersion liquid, water alone may be used as a dispersion medium, or a mixed solvent of water and other organic solvents (for example, alcohols such as ethanol), surfactants, acids, bases, etc. is used. May be.

  By the oxidation treatment and refinement treatment of the natural cellulose fiber as described above, the hydroxyl group at the C6 position of the cellulose structural unit is selectively oxidized to a carboxyl group via an aldehyde group, and the carboxyl group content is 0.1 to A highly refined highly crystalline cellulose fiber having an average fiber diameter of 200 nm or less, composed of 3 mmol / g cellulose, can be obtained. This highly crystalline cellulose fiber has a cellulose I-type crystal structure. This means that the fine cellulose fiber used in the present invention is a fiber obtained by surface-oxidizing a naturally-derived cellulose solid raw material having an I-type crystal structure. In other words, natural cellulose fibers have a high-order solid structure in which fine fibers called microfibrils produced in the process of biosynthesis are bundled to form a high-order solid structure. The fine cellulose fiber is obtained by weakening the hydrogen bond between them by introduction of the aldehyde group or carboxyl group by the oxidation treatment, and further through the refinement treatment. And by adjusting the conditions for the oxidation treatment, the polarity can be changed by increasing or decreasing the carboxyl group content within a predetermined range, and by the electrostatic repulsion or refinement treatment of the carboxyl group, The average fiber diameter, average fiber length, average aspect ratio, etc. can be controlled.

  The layered inorganic compound which is the other material constituting the film-like body according to the present invention is used for the purpose of further enhancing the gas barrier property of the film-like body. As the layered inorganic compound, a crystalline inorganic compound having a layered structure can be used. Specific examples of the inorganic compound include clay minerals represented by kaolinite group, smectite group, mica group and the like. Examples of kaolinite group clay minerals include kaolinite. Examples of smectite group clay minerals include montmorillonite, bentonite, saponite, hectorite, piderite, stevensite, and nontronite. Examples of the mica group clay mineral include vermiculite, halloysite, and tetrasilicic mica. Moreover, hydrotalcite etc. which are layered double hydroxides can also be used.

  A layered inorganic compound other than clay mineral can be used. Examples of such compounds include layered structures such as titanates, niobates, manganates, phosphates, tin oxides, cobalt oxides, copper oxides, iron oxides, nickel oxides, platinum oxides, ruthenium oxides. And metal oxides such as rhodium oxide, or composite oxides of these component elements. Graphite can also be used.

  The above various layered inorganic compounds may be natural or synthesized. These various layered inorganic compounds can be used alone or in combination of two or more. In particular, among the layered inorganic compounds, montmorillonite and tetrasilicic mica are preferably used because they have particularly high water vapor barrier properties or oxygen barrier properties in a high humidity atmosphere.

  As the layered inorganic compound, it is particularly preferable to use a negatively charged compound from the viewpoint of further improving the gas barrier property of the film-like body, particularly the water vapor barrier property or the oxygen barrier property in a high humidity atmosphere. This is because the electrostatic repulsion between the layered inorganic compound and the fine cellulose fibers contained in the coating film is maintained in the drying process in the preferred method for producing the film-like body described later. It is thought that this is because the high dispersibility is maintained and composited. The specific charge amount of the layered inorganic compound is preferably 1 to 1000 eq / g, more preferably 20 to 800 eq / g, more preferably 100 to 500 eq, provided that this is a negative charge amount. / G. The amount of charge is measured by the following method.

  A dispersion is prepared by diluting the layered inorganic compound to 0.1% by mass with ion-exchanged water. Using a particle charge meter (PCD 03, Mutek), the volume of the cationic titration solution (0.001N polydiallyldimethylammonium chloride, purchased from BTG Mutek) consumed to neutralize 10 g of this dispersion taking measurement. The charge amount of the inorganic compound is calculated from the consumption amount.

  The layered inorganic compound is also preferably highly swellable by a solvent. By using such a layered inorganic compound having a large swelling property, in the film-like body in which the layered inorganic compound and fine cellulose fiber are mixed, both are not simply mixed and dispersed, but between the layers of the inorganic layered compound. As the fine cellulose fiber expands, the inorganic layered compound and the fine cellulose fiber are combined in a nanoscale. Therefore, it is considered that the film-like body has a high gas barrier property, particularly a water vapor barrier property and an oxygen barrier property in a high humidity atmosphere. Usually, the distance between the layers of the layered inorganic compound in a dry state depends on ions existing between the layers. For example, in the case of sodium ions, the distance between the layers is as small as about 10 mm or less. However, particularly in the case of a film-like body using fine cellulose fibers having an average fiber diameter of 3 to 4 nm, the fine cellulose fibers enter between the layers of the inorganic layer-like compound, so that the crystal plane of the layered inorganic compound contained in the film-like body. The distance, that is, the distance between the layers of the layered inorganic compound is expanded to 3 nm or more. In particular, in a film-like body using fine cellulose fibers having an average fiber diameter of 3 to 4 nm, the distance between the layers of the inorganic layered compound is preferably 3 nm or more, more preferably 3 to 100 nm, and even more preferably 3 to 10 nm. High gas barrier property. The distance between the layers of the layered inorganic compound can be determined from X-ray diffraction method or cross-sectional observation of the film-like body by an electron microscope.

  The average particle size of the layered inorganic compound is preferably 0.01 to 10 μm, more preferably 0.1 to 6 μm, and still more preferably 0.1 to 4 μm. By using a layered inorganic compound having an average particle diameter in this range, the dispersibility of the layered inorganic compound in the film-like body can be improved, and the gas barrier property of the film-like body can be further enhanced. The average particle size is measured by the following method. First, the layered inorganic compound is diluted to 0.05% by mass with ion exchange water. The particle size distribution is measured using a laser diffraction particle size distribution analyzer (SALD-300V, analysis software WingSALD-300V, manufactured by Shimadzu Corporation). The average value of the particle size distribution is calculated and defined as the average particle size. The refractive index is 1.6 for montmorillonite, mica, tetralithic mica, talc, saponite, and magnesium oxide, and 2.6 for titanate.

  The film-like body according to the present invention is also characterized by the ratio of fine cellulose fibers and layered inorganic compound. This ratio is one of the factors affecting the gas barrier properties of the film-like body according to the present invention. From this viewpoint, the mass ratio (layered inorganic compound / fine cellulose fiber) of the layered inorganic compound and the fine cellulose fiber in the film-like body is 0.01 to 100, preferably 0.01 to 10, More preferably, it is 0.1-10, More preferably, it is 0.1-3. Within this range, the gas barrier property can be improved while maintaining the transparency of the film-like body. In particular, when the mass ratio is 0.1 to 3, the water vapor barrier property and the oxygen barrier property can be further improved. This mass ratio can be calculated from the charged amounts of the fine cellulose fiber and the layered inorganic compound when preparing a mixed dispersion containing the fine cellulose fiber and the layered inorganic compound. Alternatively, it can be calculated by thermogravimetric analysis of the film-like body. The mass ratio between the layered inorganic compound and the fine cellulose fiber in the film-like body by thermogravimetric analysis is calculated by the following method.

Using a thermogravimetric analyzer (Seiko Instruments Co., Ltd., TG / DTA6300), about 10 mg of a film-like body was precisely weighed, and the change in weight under an air flow was measured. The measurement was performed at the following temperature settings.
The temperature was raised from 30 ° C. to 500 ° C. (rate 40 ° C./min), held at 500 ° C. for 30 minutes, and the temperature was lowered from 500 ° C. to 30 ° C. (rate 40 ° C./min).
Under the above conditions, the cellulose component is almost completely burned, and the layered inorganic compound is nonflammable. Therefore, the content (% by mass) of the layered inorganic compound in the film is given by 100 w ₀ / w ₁ (w ₀ : measurement) Pre-weight, w ₁ : weight after measurement). From this value, the mass ratio (layered inorganic compound / fine cellulose fiber) was calculated.

  In addition to fine cellulose fibers and layered inorganic compounds, the film-like body may be a known filler, a colorant such as a pigment, an ultraviolet absorber, an antistatic agent, a water-resistant agent (such as a silane coupling agent), or a cross-linking as necessary. An agent (for example, an additive having a reactive functional group such as an epoxy group, an isocyanate group, an aldehyde group), a metal salt, colloidal silica, alumina sol, titanium oxide, or the like can be blended. The film-like body preferably contains a crosslinking agent.

  The crosslinking agent is used for the purpose of crosslinking fine cellulose fibers. For this purpose, crosslinking agents include dialdehydes such as glyoxal and glutaraldehyde; magnesium sulfate, magnesium chloride, calcium carbonate, calcium chloride, sodium chloride, potassium chloride, lithium chloride, sodium sulfate, copper sulfate, silver nitrate, chloride Polyvalent or monovalent water-soluble metal salts such as zinc and aluminum sulfate can be used. When the film-like body contains a cross-linking agent, an advantageous effect is obtained in that the water vapor barrier property and the oxygen barrier property of the film-like body are improved. From the viewpoint of further improving the water vapor barrier property and oxygen barrier property of the film-like body, it is preferable to use a dialdehyde or a water-soluble salt of an alkaline earth metal element as a crosslinking agent. The content of the crosslinking agent in the film-like body is preferably 0.1 to 200% by mass, particularly 1 to 50% by mass with respect to the mass of fine cellulose fibers.

  Next, a method for producing a film-like body according to the present invention will be described. The film-like body according to the present invention can be obtained by applying a mixed dispersion obtained by dispersing fine cellulose fibers and a layered inorganic compound in a liquid medium to form a coating film and drying the coating film. Specifically, this production method comprises a step (b) of producing a mixed dispersion by mixing a layered inorganic compound and a dispersion of fine cellulose fibers, and forming a coating film from the mixed dispersion. (C). Further, prior to the step (b), the production method may include a step (a) of producing a dispersion by dispersing the layered inorganic compound in a liquid medium.

  As the dispersion of fine cellulose fibers used in the step (b), for example, the dispersion obtained in the above-described production process of fine cellulose fibers can be used as it is. Or what disperse | distributed the powdery fine cellulose fiber obtained by manufacture of the above-mentioned fine cellulose fiber to the liquid medium can also be used. As the liquid medium, water is preferable. In addition, a mixed solvent of water-soluble organic solvents (alcohols, ethers, ketones, etc.) and water can be used. The density | concentration of the fine cellulose fiber in the dispersion liquid of a fine cellulose fiber is suitably adjusted so that the density | concentration of the fine cellulose fiber in a mixed dispersion liquid may become the range mentioned later.

  In the step (b), a layered inorganic compound in a dry state may be added and mixed in the dispersion of fine cellulose fibers, or vice versa. Further, as described above, the step (a) is performed prior to the step (b), and the dried layered inorganic compound is dispersed in a liquid medium to form a dispersion, and this dispersion is mixed with a dispersion of fine cellulose fibers. Also good. By performing the step (a) prior to the step (b), it is possible to more uniformly disperse the layered inorganic compound and the fine cellulose fibers in the mixed dispersion as compared with the case where the step (a) is not performed. There is an advantage of being. As a liquid medium for dispersing the layered inorganic compound, the same liquid medium as for dispersing fine cellulose fibers can be used. In this case, the liquid medium for dispersing the layered inorganic compound and the liquid medium for dispersing the fine cellulose fibers may be the same or different. The concentration of the layered inorganic compound in the dispersion of the layered inorganic compound is appropriately adjusted so that the concentration of the layered inorganic compound in the mixed dispersion is within the range described below.

  The concentration of fine cellulose fibers in the mixed dispersion is preferably 0.1 to 50% by mass, particularly preferably 0.5 to 10% by mass. On the other hand, the concentration of the layered inorganic compound is preferably 0.1 to 50% by mass, particularly preferably 0.1 to 10% by mass. By setting the concentration within this range, the viscosity of the dispersion becomes suitable for coating. The viscosity of the dispersion is preferably, for example, 10 to 5000 mPa · s.

  In the step (c), the obtained mixed dispersion can be cast-coated on the surface of a smooth substrate such as a glass plate or a plastic film. Alternatively, the dispersion can be applied by spraying or dipping. Thereby, a coating film is formed. By subjecting the coating film to natural drying or heat-forced drying, a desired film-like body is obtained. In this case, the gas barrier property of the obtained film-like body, in particular, the oxygen barrier property in a high humidity atmosphere, is improved when the coating film is heated and dried rather than naturally dried. In the case of forced drying by heating, it is preferable to heat the coating film at 40 to 300 ° C, particularly 90 to 200 ° C. As a heating means, for example, an electric drying furnace (natural convection type or forced convection type), a hot air circulation type drying furnace, a drying furnace using heating with far infrared rays and hot air circulation in combination, or a reduced pressure drying furnace capable of reducing pressure while heating is used. Can be employed. What is necessary is just to set a heating time suitably according to the dry state of a coating film.

  Generally, the layered inorganic compound in the dispersion of the layered inorganic compound obtained in the step (a) or the mixed dispersion of the layered inorganic compound obtained in the step (b) and the fine cellulose fiber is from fine particles to coarse particles. Exist as a mixture with particles of various particle sizes. In particular, coarse particles may reduce the transparency, gas barrier properties, strength, adhesion to the substrate, and the like of the film-like body. Therefore, in this production method, in the step (a) or (b), further separation treatment of coarse particles of the layered inorganic compound is further performed, so that more transparency, gas barrier properties, film strength, and film adhesion to the substrate are obtained. A film-like body excellent in the above can be obtained.

  In the step (a), the coarse particles of the layered inorganic compound are separated from the dispersion after the dispersion of the layered inorganic compound is produced. In the step (b), a mixed dispersion of fine cellulose fibers and a layered inorganic compound is produced, and then the mixed dispersion is performed.

  Examples of the separation method include a filtration separation method and a centrifugal separation method. These separation treatments preferably remove coarse particles having a particle size of 10 μm or more.

  In the filtration separation method, coarse particles of the layered inorganic compound are separated by filtering the dispersion of the layered inorganic compound or the mixed dispersion of the layered inorganic compound and the fine cellulose fiber using a filter having a predetermined pore size. . When filtration is performed in step (a), the filtrate from which coarse particles have been separated is collected, and the collected filtrate is mixed with a dispersion of fine cellulose fibers in step (b) to form a mixed dispersion. A film-like body can be obtained by subjecting the dispersion to step (c). When filtration is performed in the step (b), the filtrate obtained by separating the coarse particles is recovered, and the recovered filtrate is subjected to the step (c) to obtain a membrane. Examples of the filtration separation method include vacuum filtration, natural filtration, and pressure filtration.

  In the centrifugal separation method, coarse particles of the layered inorganic compound are separated from the dispersion of the layered inorganic compound or the mixed dispersion of the layered inorganic compound and the fine cellulose fiber according to the specific gravity (or mass) of the particles. When centrifugal separation is performed in the step (a), a part of the dispersion of the layered inorganic compound separated from the coarse particles is recovered, and the recovered dispersion is mixed with the dispersion of the fine cellulose fibers in the step (b). A film-like body can be obtained by forming a mixed dispersion and subjecting the mixed dispersion to step (c). When centrifugation is performed in the step (b), a part of the mixed dispersion separated from the coarse particles is recovered, and a membrane-like body can be obtained by subjecting the recovered separated solution to the step (c). Centrifugation can be performed using a known apparatus. Centrifugation is preferably 3000 to 20000 G, more preferably 10,000 to 15000 G, preferably 1 to 30 minutes, and more preferably 5 to 15 minutes.

  In this production method, the above-mentioned crosslinking agent is allowed to coexist in the dispersion of the layered inorganic compound obtained in step (a) or in the mixed dispersion of the layered inorganic compound obtained in step (b) and fine cellulose fibers. May be. By carrying out like this, a crosslinking agent can be contained in a film-form body. In place of this method, in step (c), a coating film is formed from the mixed dispersion, a crosslinking agent is applied to the formed coating film, and the coating film is dried, whereby the crosslinking agent is added to the film-like body. It can be included. In this case, the mixed dispersion of the layered inorganic compound and the fine cellulose fibers does not need to contain a cross-linking agent, but it does not prevent the cross-linking agent from being included. There is no restriction | limiting in particular in the method of giving a crosslinking agent, What is necessary is just to employ | adopt the method according to the property of the crosslinking agent. For example, when the crosslinking agent is a liquid, it is applied to the membrane using a method of spraying, coating or casting the crosslinking agent on the surface of the membrane, or a method of immersing the membrane in the crosslinking agent. be able to. Alternatively, the liquid may be diluted with water or an organic solvent to form a diluted solution, the concentration of the crosslinking agent in the diluted solution may be adjusted, and the diluted solution applied to the coating film. When the cross-linking agent is solid, a solution can be prepared by dissolving the cross-linking agent in a solvent capable of dissolving the cross-linking agent, and the solution can be applied to the coating film. For example, when the crosslinking agent is a solid water-soluble salt, an aqueous solution can be prepared by dissolving the water-soluble salt in water, and the aqueous solution can be applied to the coating film. The amount of the cross-linking agent to be used is appropriately adjusted so that the ratio of the cross-linking agent in the produced film is in the range described above.

The film-like body formed by drying the coating film can be used as it is laminated on the base material, or it can be peeled off from the base material alone and laminated on another base material after peeling. It can also be used. The film-like body has a high barrier property against various gases, for example, oxygen, water vapor, nitrogen, carbon dioxide, etc., which are gases contained in the atmosphere. Specifically, the water vapor permeability is a low level of 5 to 24 (g / m ² · day), preferably 5 to 22 (g / m ² · day). The oxygen permeability at 50% RH is preferably 0.01 to 20 (× 10 ⁻⁵ cm ³ / m ² · day · Pa), more preferably 0.01 to 5 (× 10 ⁻⁵ cm ³ / m). ² · day · Pa). The film-like body may have not only a property of blocking a plurality of gases such as water vapor and oxygen but also a property of blocking only a specific gas. For example, a film-like body having no oxygen barrier property but having a water vapor barrier property can be used as a barrier material that selectively inhibits the permeation of water vapor. The gas to be subject to barrier properties is appropriately selected depending on the application. Water vapor permeability and oxygen permeability are measured by the following methods.

(1) Water vapor permeability (g / (m ² · day))
Based on JIS Z208, measurement was performed under conditions of an environment of 40 ° C. and 90% RH using a cup method.
(2) Oxygen permeability (cm ³ / (m ² · day · Pa))
Based on the measurement method of JIS K-7126-2 appendix A (isobaric method), it measured using oxygen permeability measuring apparatus OX-TRAN2 / 21 (model ML & SL, Hitachi High-Tech Technologies). The measurement environment was 23 ° C. or 30 ° C., and the humidity was evaluated at 0% RH, 50% RH, and 70% RH, respectively. For example, “oxygen permeability at 23 ° C. and 50% RH” is measured in an environment of oxygen gas at 23 ° C. and humidity 50% RH and nitrogen gas (carrier gas) at 23 ° C. and humidity 50%. The water vapor permeability and oxygen permeability were measured after acclimatization for 24 hours or more in an environment of 23 ° C. and 50% RH after forming a film-like molded body.

  Moreover, the film-like body of the present invention has good transparency. The transparency of the film-like body can be evaluated using, for example, a haze value (%). The haze value of the film-like body is measured using a haze meter NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7136.

  The film-like body according to the present invention is suitably used for applications such as packaging materials such as foods, cosmetics, medicines, medical equipment, machine parts, electronic devices, and clothing using the high gas barrier property.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “mass%”.

[Example 1]
(1) Production of fine cellulose fiber Conifer bleached kraft pulp (manufacturer: Fletcher Challenge Canada, trade name “Machenzie”, CSF 650 ml) was used as a natural fiber. As TEMPO, a commercial product (manufacturer: ALDRICH, Free radical, 98%) was used. As sodium hypochlorite, a commercial product (manufacturer: Wako Pure Chemical Industries, Ltd. Cl: 5%) was used. A commercial product (manufacturer: Wako Pure Chemical Industries, Ltd.) was used as sodium bromide. First, 100 g of bleached kraft pulp fiber of coniferous trees was sufficiently stirred with 9900 g of ion-exchanged water, and then TEMPO 1.25%, sodium bromide 12.5%, sodium hypochlorite 28.4% with respect to 100 g of pulp mass. Were added in this order. Using a pH stud, 0.5M sodium hydroxide was added dropwise to maintain the pH at 10.5, and an oxidation reaction was performed. After 120 minutes of oxidation, dropping was stopped to obtain oxidized pulp. The oxidized pulp was thoroughly washed with ion-exchanged water and then dehydrated. Thereafter, 3.9 g of oxidized pulp and 296.1 g of ion-exchanged water were stirred for 120 minutes with a mixer (Vita-Mix-Blender ABSOLUTE, manufactured by Osaka Chemical Co., Ltd.). By the operation, the fiber was refined to obtain a dispersion of fine cellulose fibers. The solid content concentration of the dispersion was 1.3%. The average fiber diameter of the fine cellulose fibers was 3.1 nm, the average aspect ratio was 240, and the carboxyl group content was 1.2 mmol / g.

(2) Production of membrane-like material Montmorillonite (product name: Kunipia F, manufactured by Kunimine Kogyo Co., Ltd.) and ion-exchanged water are mixed and stirred with a magnetic stirrer for 24 hours to obtain a 2.2% montmorillonite dispersion. Obtained. This montmorillonite aqueous dispersion 8.9 g and the fine cellulose fiber dispersion (solid content concentration 1.3%) 15 g were mixed and stirred with a magnetic stirrer for 24 hours to obtain a mixed dispersion. The solid content concentration of this dispersion was 1.6%. This dispersion was applied to the surface of a 25 μm thick polyethylene terephthalate film using a bar coater to form a wet film thickness of 100 μm. This coating film was dried at room temperature for 2 hours and then heated and forcedly dried using a natural convection type electronic drying furnace. Drying conditions were 150 ° C. and 30 minutes. In this way, a desired film-like body was obtained. The oxygen permeability and water vapor permeability (JIS Z0208) of the film-like body were measured. The measurement environment of oxygen permeability was constant at a temperature of 23 ° C., and humidity was measured at 0% RH, 50% RH, and 70% RH, respectively. The results are shown in Table 1 below. Moreover, the transparency of the film-like body was measured by the method described above. The results are shown in Table 3 below.

[Examples 2 and 3]
A film-like body was obtained in the same manner as in Example 1 except that the montmorillonite shown below was used.
Example 2 Product name: Bengel FW, manufactured by Hojun Co., Ltd. Example 3 Product name: Bengel A, manufactured by Hojun Co., Ltd. The obtained membrane was measured for oxygen permeability and water vapor permeability. The measurement environment for the oxygen permeability was 50% RH. The results are shown in Table 2.

[Examples 4 and 5]
A film-like body was obtained in the same manner as in Example 1 except that mica shown below was used instead of montmorillonite used in Example 1.
-Example 4 Product name: Somasif ME-100, manufactured by Co-op Chemical Co., Ltd.-Example 5 Product name: Micromica MK-200, manufactured by Co-op Chemical Co., Ltd. The obtained membrane was the same as in Example 2. Was measured. The results are shown in Table 2.

Example 6
A film-like body was obtained in the same manner as in Example 1 except that talc (product name: SG2000, manufactured by Toshin Kasei Co., Ltd.) was used instead of montmorillonite used in Example 1. About the obtained film-form body, the same measurement as Example 2 was performed. The results are shown in Table 2.

[Examples 7 and 8]
A film-like body was obtained in the same manner as in Example 1 except that the synthetic saponite shown below was used instead of the montmorillonite used in Example 1.
-Example 7 Product name: Smecton SA, manufactured by Kunimine Industry Co., Ltd.-Example 8 Synthetic saponite, Kunimine Industry Co., Ltd.
About the obtained film-form body, the same measurement as Example 2 was performed. The results are shown in Table 2.

Example 9
A film-like body was obtained in the same manner as in Example 1 except that a layered titanate (product name: Terrases, manufactured by Otsuka Chemical Co., Ltd.) was used instead of the montmorillonite used in Example 1. About the obtained film-form body, the same measurement as Example 2 was performed. The results are shown in Table 2.

Example 10
A film-like body was obtained in the same manner as in Example 1 except that tetrasilicic mica (product name: NTS-5, manufactured by Topy Industries, Ltd.) was used instead of montmorillonite used in Example 1. About the obtained film-like body, the same measurement as Example 1 was performed. The results are shown in Table 1.

Example 11
A film-like body was obtained in the same manner as in Example 1 except that the amount of the montmorillonite aqueous dispersion used in Example 1 was reduced from 8.9 g to 2.2 g. The obtained film-like body was measured in the same manner as in Example 1 (except for the oxygen permeability at 0% RH). The results are shown in Table 3.

Example 12
A film-like body was obtained in the same manner as in Example 1 except that the amount of the montmorillonite aqueous dispersion used in Example 1 was reduced from 8.9 g to 4.5 g. About the obtained film-form body, the same measurement as Example 11 was performed. The results are shown in Table 3.

Example 13
A film-like body was obtained in the same manner as in Example 1 except that the amount of the montmorillonite aqueous dispersion used in Example 1 was increased from 8.9 g to 17.8 g. About the obtained film-form body, the same measurement as Example 11 was performed. The results are shown in Table 3.

Example 14
A film-like body was obtained in the same manner as in Example 1 except that the amount of the montmorillonite aqueous dispersion used in Example 1 was increased from 8.9 g to 35.6 g. About the obtained film-form body, the same measurement as Example 11 was performed. The results are shown in Table 3.

[Examples 15 to 18]
The amount of the fine cellulose fiber dispersion used in Example 1 was increased from 15 g to 50 g, and instead of 8.9 g of the montmorillonite aqueous dispersion used in Example 1, 6% tetrasilicic mica aqueous dispersion ( Product name: NTS-5, manufactured by Topy Industries Co., Ltd.) 1.1 g (Example 15), 2.2 g (Example 16), 10.8 g (Example 17) and 21.7 g (Example 18) A film-like body was obtained in the same manner as in Example 1 except that it was used. About the obtained film-form body, the same measurement as Example 11 was performed. The results are shown in Table 3.

[Comparative Example 1]
In the same manner as in Example 1, a fine cellulose fiber dispersion (solid content concentration: 1.3%) was obtained. This dispersion was applied to the surface of a 25 μm thick polyethylene terephthalate film using a bar coater to form a wet film thickness of 100 μm. This coating film was dried at room temperature for 2 hours and then heated and forcedly dried using a natural convection type electronic drying furnace. Drying conditions were 150 ° C. and 30 minutes. A film-like body was thus obtained. The oxygen permeability and water vapor permeability of the membrane were measured. The measurement environment of oxygen permeability was constant at a temperature of 23 ° C., and humidity was measured at 0% RH, 50% RH, and 70% RH, respectively. The results are shown in Table 1.

[Comparative Example 2]
A film-like body was obtained in the same manner as in Example 1 except that magnesium oxide powder (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of montmorillonite used in Example 1. About the obtained film-form body, the same measurement as Example 2 was performed. The results are shown in Table 2.

  Table 1 shows the water vapor permeability of the membrane and the oxygen permeability under each humidity environment. As is apparent from the results shown in Table 1, the film-like bodies of fine cellulose fibers containing the layered inorganic compound (Examples 1 and 10) are superior in water vapor barrier properties compared to Comparative Example 1 not containing the layered inorganic compound. In addition, it can be seen that it has a high oxygen barrier property even in a humidity environment of 0 to 70% RH.

  Table 2 shows the influence of the type of layered inorganic compound, charge amount, and average particle size. As is clear from the results shown in Table 2, the film-like bodies (Examples 1 to 10) of fine cellulose fibers containing a layered inorganic compound were superior in water vapor barrier properties as compared to Comparative Example 1. Regarding oxygen barrier properties, in particular, Examples 1, 2, 3, and 10 in which the average particle diameter of the layered inorganic compound is 0.1 to 4 μm and the negative charge amount is 100 to 500 eq / g, a dramatic improvement can be confirmed. It was. In Comparative Example 2, since the added inorganic compound is not layered and does not have negative charge, it is considered that the compound was not sufficiently dispersed and composited and the gas barrier property was not improved.

  In the result shown in Table 3, Examples 1 and 11-18 differ in the mass ratio (layered inorganic compound / cellulose fiber) of a layered inorganic compound and a fine cellulose fiber. As shown in the table, each example is superior to Comparative Example 1 in water vapor barrier property and oxygen barrier property, and in particular, the mass ratio between the layered inorganic compound and the fine cellulose fiber (layered inorganic compound / cellulose fiber). In Example 1, 11-13 and 15-18 which are 0.1-3, it improved dramatically.

Example 19
A coating film was formed in the same manner as in Example 17, using the same mixed dispersion as that used in Example 17. An aqueous solution of 5% glyoxal (manufactured by Wako Pure Chemical Industries, Ltd.) as a crosslinking agent was sprayed onto the coating film in a wet state (within 1 minute after application) by a commercially available spray. The amount of spraying was such that glyoxal was 10% with respect to the mass of fine cellulose fibers in the coating film. This coating film was dried at room temperature for 2 hours, and then heated and forcedly dried using a natural convection type electronic drying furnace to obtain a film-like body. Drying conditions were 150 ° C. and 30 minutes. About the obtained film-like body, the item of Table 4 was evaluated.

Example 20
A 0.5M magnesium sulfate aqueous solution was used as a crosslinking agent. The amount of spraying was such that magnesium sulfate was 12% with respect to the mass of fine cellulose fibers in the coating film. Except for this, a film-like body was obtained in the same manner as in Example 19. The obtained film-like body was evaluated in the same manner as in Example 19. The results are shown in Table 4.

[Comparative Example 3]
A coating film was formed in the same manner as in Comparative Example 1. 5% glyoxal was sprayed as a cross-linking agent on the wet film (within 1 minute after application). The amount of spraying was such that glyoxal was 10% with respect to the mass of fine cellulose fibers in the coating film. This coating film was dried under the same conditions as in Example 19 to obtain a film-like body. The obtained film-like body was evaluated in the same manner as in Example 19. The results are shown in Table 4.

[Comparative Example 4]
A 0.5 M magnesium sulfate aqueous solution was used as a crosslinking agent. The amount of magnesium sulfate aqueous solution used was such that magnesium sulfate was 12% with respect to the mass of fine cellulose fibers in the coating film. Except for this, a film-like body was obtained in the same manner as in Comparative Example 3. The obtained film-like body was evaluated in the same manner as in Example 19. The results are shown in Table 4.

  Examples 19 and 20 are film-like bodies composed of fine cellulose fibers, a layered inorganic compound, and a crosslinking agent. The film-like bodies of these examples were superior in both water vapor barrier properties and oxygen barrier properties as compared with the film-like bodies of Comparative Examples 3 and 4 not containing the layered inorganic compound. In particular, the film-like body of Example 20 has an oxygen permeability of about ½ at 23 ° C. and 70% RH compared to the film-like body of Example 17 that does not contain a crosslinking agent. The improvement effect of the high gas barrier property by was confirmed.

Example 21
The fine cellulose fiber dispersion (solid content concentration 1.3%) used in Example 1 was diluted with ion-exchanged water to adjust the solid content concentration to 1.0%. 50 g of this fine cellulose fiber dispersion and 0.8 g of 6% tetrasilicic mica dispersion (product name: NTS-5, manufactured by Topy Industries, Ltd.) are mixed and stirred for 24 hours with a magnetic stirrer. A mixed dispersion was obtained. The solid content concentration and mass ratio of this dispersion were as shown in Table 5. Using the obtained mixed dispersion, a film-like body was obtained in the same manner as in Example 1. The items described in Table 5 were evaluated for the obtained film-like bodies.

[Examples 22 to 24]
The same mixed dispersion as used in Example 21 was subjected to vacuum filtration using the filter or filter paper described below, and the coarseness of the layered inorganic compounds contained in the mixed dispersion The particles were separated and the filtrate was collected.
Example 22: Glass filter (VIDEC 11G-2, pore diameter 40-50 μm)
Example 23: Filter paper (Whatman No. 41, pore diameter 20-25 μm)
Example 24: Glass filter (Shibata Kagaku 3GP16, pore size 10-16 μm)
The solid content of the collected filtrate was as shown in Table 5. Using the collected filtrate, a membrane was obtained in the same manner as in Example 1. The items described in Table 5 were evaluated for the obtained film-like bodies. The mass ratio between the layered inorganic compound and the fine cellulose fibers was measured by performing the thermogravimetric analysis described above on the film-like body obtained by pouring the collected filtrate into a petri dish and vacuum drying.

[Examples 26 to 28]
Tetralithic mica (product name: NTS-5, manufactured by Topy Industries Co., Ltd.) 6% dispersion (45 g) was placed in a conical tube, and a centrifuge (universal cooling centrifuge 5922, manufactured by Kubota Corporation) was used. And centrifuged at 1,000 rpm for 10 minutes. Centrifugation separated tetrasilicic mica into four layers in a conical tube. Of the separated layers, the first to third layers from the top were collected with a dropper. The solid content concentration of tetralithic mica in each layer was 0.5% (first layer), 3.1% (second layer), and 8.2% (third layer), respectively.

  10 g (first layer) and 1.6 g (first layer) of the recovered tetrasilicic mica of the first to third layers with respect to 50 g of fine cellulose fibers (solid content concentration 1.0%) used in Example 21. Second layer) and 0.6 g (third layer) were added and stirred well to obtain a mixed dispersion. Thereafter, a film-like body was obtained in the same manner as in Example 21. The items described in Table 5 were evaluated for the obtained film-like bodies.

Example 29
45 g of the mixed dispersion (fine cellulose fiber / tetralithic mica) used in Example 21 was placed in a conical tube, and 10 times at 10,000 rpm using a centrifuge (universal cooling centrifuge 5922, manufactured by Kubota Corporation). Centrifuged for minutes. The mixed dispersion was separated into two layers in a conical tube by centrifugation. The upper first layer of the separated layers was collected with a dropper. The solid content concentration of the mixed dispersion of the first layer was 1.1%. Using this first layer mixed dispersion, a film-like body was obtained in the same manner as in Example 21. The items described in Table 5 were evaluated for the obtained film-like bodies. The mass ratio between the layered inorganic compound and the fine cellulose fibers was measured by the same method as in Examples 22-24.

[Comparative Example 5]
A film-like body was obtained in the same manner as in the Example using only the fine cellulose fiber (solid content concentration 1.0%) used in Example 21 as a raw material. However, the coating film was dried at 150 ° C. for 30 minutes. The items described in Table 5 were evaluated for the obtained film-like bodies.

  Examples 22-24 are the examples which manufactured the film-like body after isolate | separating a coarse particle by filtration. Examples 26 to 29 are examples in which membranes were produced after separating coarse particles by centrifugation. It can be seen that the film-like bodies obtained in these examples have improved oxygen barrier properties compared to the film-like body of Example 21 in which the coarse particles were not separated. The reason for this is thought to be that coarse particles were removed from the dispersion by filtration or centrifugation. Among the examples where filtration separation was performed, the film-like body of Example 23 was particularly improved in oxygen barrier properties. This means that it is important to set a pore diameter that allows efficient separation of coarse particles. On the other hand, it can be seen that, among the examples subjected to centrifugation, the film-like bodies of Examples 26 and 27 improved not only the oxygen barrier property but also the transparency.

  Apart from the above evaluation, transmission electron microscope images of cross sections of the film-like bodies of Examples 15 and 17 and Comparative Example 1 were taken. The results are shown in FIGS. The black part shows the layered inorganic compound, and the gray part shows the cellulose part. In the film-like bodies of Examples 15 and 17 shown in FIGS. 1 and 2, it can be confirmed that a layered material having a thickness of 1 nm or less is dispersed in the fine cellulose fiber film. In addition, since a plurality of portions where the distance between the layered product and the layered product is wider than the fiber diameter (3.1 nm) of the fine cellulose fiber used can be confirmed, the fine cellulose fiber expands it between the layers of the layered inorganic compound. It entered, and it was confirmed that the fine cellulose fiber and the layered inorganic compound are in a composite state on the nanoscale. In particular, in Example 17, a number of portions where the distance between layers was increased by 3 to 10 nm were observed. On the other hand, in the film-like body of Comparative Example 1 shown in FIG. 3, the structure shown in FIGS. 1 and 2 is not observed.

Claims (7)

A fine cellulose fiber and a layered inorganic compound composed of montmorillonite or tetrasilicic mica, and the carboxyl group content of cellulose constituting the fine cellulose fiber is 0.1 to 3 mmol / g, and the average of the layered inorganic compound The particle size is 0.1 to 4 μm, the negative charge is 100 to 500 eq / g, and the mass ratio of the layered inorganic compound and the fine cellulose fiber (layered inorganic compound / cellulose fiber) is 0.1 to 3 Some membranous body. The film-like body according to claim 1 , further comprising a crosslinking agent. It is a manufacturing method of the film-like object according to claim 1 or 2 ,
A step (b) of producing a mixed dispersion by mixing a layered inorganic compound comprising montmorillonite or tetrasilicic mica and a dispersion of fine cellulose fibers; and forming a coating from the mixed dispersion; The manufacturing method of the film-like body including the process (c) to dry. The method for producing a film-like body according to claim 3 , wherein in the step (b), after the mixed dispersion is produced, coarse particles of the layered inorganic compound in the mixed dispersion are subjected to separation treatment. Furthermore, the manufacturing method of the film-form body of Claim 3 or 4 including the process (a) which disperse | distributes the said layered inorganic compound in a liquid medium prior to the said process (b), and manufactures a dispersion liquid. The method for producing a film-like body according to claim 5 , wherein in the step (a), after the dispersion liquid is produced, the coarse particles of the layered inorganic compound in the dispersion liquid are subjected to separation treatment. The method for producing a membranous body according to claim 4 or 6, wherein the separation treatment is a filtration separation method or a centrifugal separation method.