JP6418213B2 - Fine fibrous cellulose content - Google Patents

Description

  The present invention relates to a fine fibrous cellulose-containing material having excellent fine particle dispersibility.

  In recent years, materials that use reproducible natural fibers have attracted attention due to the substitution of petroleum resources and the growing environmental awareness. Among natural fibers, fibrous cellulose having a fiber diameter of 10 to 50 μm, particularly fibrous cellulose (pulp) derived from wood has been widely used mainly as a paper product so far. As the fibrous cellulose, fine fibrous cellulose having a fiber diameter of 1 μm or less is also known.

  The aqueous suspension or dispersion of fibrous cellulose usually contains a solvent several to several hundred times the amount of fibrous cellulose. Handling such an aqueous suspension or dispersion as it is has the problems of increased storage space and increased storage and transportation costs. Therefore, it has been attempted to prepare a cellulose concentrate.

  For example, Patent Document 1 describes a method of treating an aqueous gel of nanofibril cellulose by removing water from the aqueous gel using an organic solvent miscible with water. This method maintains the aqueous gel as a separate phase, introduces the aqueous gel into an organic solvent in a controlled manner so as to form a physical entity containing nanofibril cellulose in the separated phase, and exchanges water for the organic solvent. , A method of separating a physical entity from an organic solvent. Patent Document 2 describes a bacterial cellulose concentrate characterized by containing undisaggregated bacterial cellulose in a range of 10 wt% or more and less than 75 wt%.

  Patent Document 3 discloses a cellulose fiber suspension containing a cellulose fiber, a polyvalent metal, and a volatile base, wherein the cellulose fiber has an average fiber diameter of 200 nm or less and a cellulose carboxyl group content of 0.1 to 2 mmol / g. A suspension is described. Patent Document 4 describes a method for producing a dry solid of anion-modified cellulose nanofibers, wherein the pH of an aqueous suspension of anion-modified cellulose nanofibers is adjusted to 9 to 11 and then dehydrated and dried. Has been.

Special table 2014-508228 gazette JP-A-9-316102 JP 2010-168573 A Japanese Patent Laying-Open No. 2015-134873

  As described above, Patent Documents 1 to 4 describe the preparation of cellulose concentrate. However, when the concentrate of fine fibrous cellulose is used as a thickener, there is a concern that the dispersibility of fine particles (such as titanium oxide) in an aqueous medium containing the fine fibrous cellulose is concerned. Paid attention. The examination from the above viewpoint regarding the concentrate of fine fibrous cellulose has not been sufficiently performed so far.

  The present invention has been made in view of the above problems. The problem to be solved by the present invention is to provide a fine fibrous cellulose-containing material having good dispersibility of fine particles in an aqueous medium containing fine fibrous cellulose.

  The present inventors diligently studied to solve the above problems. As a result, the dispersibility of fine particles in an aqueous medium containing the fine fibrous cellulose can be controlled by controlling the viscosity and haze value of the sample prepared using the fine fibrous cellulose-containing material under predetermined conditions, respectively. It was found that can be improved. Furthermore, the present inventors have found that the above-described viscosity and haze value can be controlled by appropriately adjusting the concentration method of the fine fibrous cellulose-containing material and the amount of substituents of the fine fibrous cellulose. The present invention has been completed based on these findings.

That is, according to the present invention, the following inventions are provided.
(1) A fine fibrous cellulose-containing material in which the content of fine fibrous cellulose is 5% by mass or more, and the following sample satisfies the following conditions A and B:
Condition A: The viscosity measured at 3 rpm and 25 ° C. using a B-type viscometer is 2800 mPa · s or more.
Condition B: The haze value is 10% or more and 50% or less.
However, the sample is a sample in which the fine fibrous cellulose-containing material is added to pure water so that the solid content concentration is 0.4% by mass, and stirred with a disperser at 1500 rpm for 5 minutes. .
(2) The fine fibrous cellulose-containing material according to (1), further comprising an organic solvent.
(3) The fine fibrous cellulose-containing material according to (2), wherein the organic solvent is isopropyl alcohol.
(4) The fine fibrous cellulose-containing material according to (2) or (3), further comprising water.
(5) The fine fibrous cellulose-containing product according to any one of (1) to (4), wherein the fine fibrous cellulose has an ionic substituent.
(6) The fine fibrous cellulose-containing product according to any one of (1) to (5), wherein the fine fibrous cellulose has a phosphate group.
(7) The fine fibrous cellulose-containing product according to any one of (1) to (6), wherein the amount of phosphate groups in the fine fibrous cellulose is 0.5 mmol / g or more.
(8) The fine fibrous cellulose-containing product according to any one of (1) to (7), wherein the content of the fine fibrous cellulose is 95% by mass or less.
(9) The fine fibrous cellulose-containing material according to any one of (1) to (8), further comprising coarse fibrous cellulose having an average fiber width of greater than 1 μm.
(10) The fine fibrous cellulose-containing material according to (9), wherein a fiber length of the coarse fibrous cellulose is 10 μm or more.
(11) The fine fibrous cellulose-containing material according to any one of (1) to (10), which is powdery.

  The fine fibrous cellulose-containing material of the present invention has good dispersibility of fine particles in an aqueous medium containing the fine fibrous cellulose.

FIG. 1 shows the relationship between the amount of NaOH dripped with respect to a fiber raw material and electrical conductivity.

  “Parts” and “%” represent ratios based on mass (parts by mass, mass%) unless otherwise specified. Values relating to the mass of fibers such as cellulose are based on the absolute dry mass (solid content), unless otherwise specified. The numerical range “X to Y” includes values at both ends unless otherwise specified. “A or / and B” means at least one of A and B unless otherwise specified, and may be A alone, B alone, or both A and B Means it may be.

<Fibrous cellulose raw material>
Although it does not specifically limit as a fibrous cellulose raw material for obtaining fibrous cellulose, It is preferable to use a pulp from the point that it is easy to acquire and it is cheap. The pulp is selected from wood pulp, non-wood pulp, and deinked pulp. Examples of wood pulp include hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), soda pulp (AP), unbleached kraft pulp (UKP), oxygen bleached kraft pulp (OKP), and dissolution. Examples include chemical pulp such as pulp (DP). Moreover, semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-ground wood pulp (CGP), mechanical pulps such as ground wood pulp (GP) and thermomechanical pulp (TMP, BCTMP), and the like are exemplified, but not particularly limited. . Non-wood pulp includes cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw and bagasse, cellulose isolated from sea squirts and seaweed, chitin, chitosan, etc., but is not particularly limited. . The deinking pulp includes deinking pulp made from waste paper, but is not particularly limited. The pulp of this embodiment may be used alone or in combination of two or more. Among the above pulps, wood pulp containing cellulose and deinked pulp are preferable in terms of availability. Among wood pulps, chemical pulp has a large cellulose ratio, so the yield of fine fibrous cellulose during fiber refinement (defibration) is high, and the degradation of cellulose in the pulp is small, and the fineness of long fibers with a large axial ratio is high. Although it is preferable at the point from which fibrous cellulose is obtained, it is not specifically limited. Of these, kraft pulp and sulfite pulp are most preferably selected, but are not particularly limited. High strength is obtained in a sheet containing fine fibrous cellulose of long fibers having a large axial ratio.

<Ionic substituent>
The fine fibrous cellulose used in the present invention preferably has an ionic substituent, but is not particularly limited thereto.
The ionic substituent may be either an anionic substituent or a cationic substituent, but is preferably an anionic substituent.

  The method for introducing an anionic substituent into the fibrous cellulose is not particularly limited, and examples thereof include an oxidation treatment or a treatment with a compound capable of forming a covalent bond with a functional group in cellulose.

  The oxidation treatment is a treatment for converting a hydroxy group in cellulose into an aldehyde group or a carboxy group. Examples of the oxidation treatment include TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidation treatment and treatment using various oxidizing agents (sodium chlorite, ozone, etc.). An example of the oxidation treatment is a method described in Biomacromolecules 8, 2485-2491, 2007 (Saito et al.), But is not particularly limited.

  The treatment with the compound can be carried out by introducing the above substituent into the fiber raw material by mixing a compound that reacts with the fiber raw material into a dry or wet fiber raw material. In order to promote the reaction at the time of introduction, a heating method is particularly effective. The heat treatment temperature for introducing the substituent is not particularly limited, but is preferably a temperature range in which thermal decomposition or hydrolysis of the fiber raw material hardly occurs. For example, it is preferable that it is 250 degrees C or less from a viewpoint of the thermal decomposition temperature of a cellulose, and it is preferable to heat-process at 100-170 degreeC from a viewpoint of suppressing hydrolysis of a cellulose.

The compound that reacts with the fiber raw material is not particularly limited as long as fine fibers can be obtained and an anionic substituent is introduced.
When introducing an anionic substituent, examples of the compound that reacts with the fiber raw material include a compound having a group derived from phosphoric acid, a compound having a group derived from carboxylic acid, a compound having a group derived from sulfuric acid, and a compound derived from sulfonic acid. And a compound having a group. A compound having at least one selected from the group consisting of a group derived from phosphoric acid, a group derived from carboxylic acid and a group derived from sulfuric acid is preferable from the viewpoint of ease of handling and reactivity with fibers. It is more preferred that these compounds form an ester or / and ether with the fiber, but there is no particular limitation.

  The amount of substituent introduced into the anionic substituent-introduced fiber (by titration method) is not particularly limited, but is preferably 0.005α to 0.11α, more preferably 0.01α to 0.08α per 1 g (mass) of fiber. If the introduction amount of the substituent is 0.005α or more, the fiber raw material can be easily refined (defibration). If the introduction amount of the substituent is 0.11α or less, dissolution of the fiber can be suppressed. However, (alpha) is the quantity (unit: mmol / g) by which the functional group which the compound which reacts with a fiber material can react, for example, a hydroxyl group and an amino group is contained per 1 g of fiber materials.

In addition, the measurement of the introduction amount (titration method) of substituents on the fiber surface can be performed by the following method, unless otherwise specified:
A fine fiber-containing slurry containing about 0.04 g of solid content in an absolutely dry mass is collected and diluted to about 50 g using ion-exchanged water. While stirring this solution, the change in the value of electrical conductivity when a 0.01N sodium hydroxide aqueous solution was added dropwise was measured, and the amount of 0.01N sodium hydroxide aqueous solution added when the value was minimized was measured. The amount dropped at the titration end point. The amount X of substituents on the cellulose surface is represented by X (mmol / g) = 0.01 (mol / l) × V (ml) / W (g). Here, V: the dripping amount (ml) of 0.01N sodium hydroxide aqueous solution, W: solid content (g) contained in the slurry containing fine fibrous cellulose.

  In conductivity titration, when alkali is added, the curve shown in FIG. 1 is given. Initially, the electrical conductivity rapidly decreases (hereinafter referred to as “first region”). Thereafter, the conductivity starts to increase slightly (hereinafter referred to as “second region”). Thereafter, the conductivity increment increases (hereinafter referred to as “third region”). The boundary point between the second region and the third region is defined as a point at which the amount of change in conductivity twice, that is, the increase (inclination) in conductivity is maximized. That is, three areas appear. Among these, the amount of alkali required in the first region is equal to the amount of strongly acidic groups in the slurry used for titration, and the amount of alkali required in the second region is the amount of weakly acidic groups in the slurry used for titration. Will be equal. When the phosphoric acid group undergoes condensation, apparently weakly acidic groups are lost, and the amount of alkali required in the second region is reduced compared to the amount of alkali required in the first region. On the other hand, the amount of strongly acidic groups coincides with the amount of phosphorus atoms regardless of the presence or absence of condensation, so that the amount of phosphate groups introduced (or the amount of phosphate groups) or the amount of substituent introduced (or the amount of substituents) is simply When said, it represents the amount of strongly acidic group.

  When the substituent to be introduced is at least one selected from the group consisting of a group derived from phosphoric acid, a group derived from carboxylic acid, and a group derived from sulfuric acid, the amount of substituent introduced is not particularly limited. 001 to 5.0 mmol / g. It may be 0.005 to 4.0 mmol / g, or 0.01 to 2.0 mmol / g. When the introduced substituent is a phosphate group, the amount of the phosphate group in the fine fibrous cellulose is preferably 0.5 mmol / g or more, and preferably 0.5 to 5.0 mmol / g. More preferably, it is more preferably 0.5 to 2.0 mmol / g.

  When a compound having a phosphoric acid-derived group is used as the compound that reacts with the fiber raw material, it is not particularly limited, but is composed of phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, polyphosphonic acid, or a salt or ester thereof. It is at least one selected from the group. Among these, a compound having a phosphoric acid group is preferable because it is low-cost, easy to handle, and can further improve the refinement (defibration) efficiency by introducing a phosphoric acid group into the fiber raw material, but is not particularly limited. .

  Although it does not specifically limit as a compound which has a phosphoric acid group, Lithium dihydrogen phosphate which is phosphoric acid and the lithium salt of phosphoric acid, Dilithium hydrogen phosphate, Trilithium phosphate, Lithium pyrophosphate, Lithium polyphosphate is mentioned. . Furthermore, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate and sodium polyphosphate which are sodium salts of phosphoric acid are mentioned. Furthermore, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, and potassium polyphosphate which are potassium salts of phosphoric acid are mentioned. Further examples include ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium polyphosphate, which are ammonium salts of phosphoric acid.

  Of these, phosphoric acid, sodium phosphate, phosphoric acid potassium salt, and phosphoric acid ammonium salt are preferred from the viewpoint of high efficiency in introducing a phosphate group and easy industrial application. Sodium dihydrogen phosphate Although disodium hydrogen phosphate is more preferable, it is not particularly limited.

  In addition, the compound is preferably used as an aqueous solution because of the uniformity of the reaction and the introduction efficiency of the group derived from phosphoric acid, but it is not particularly limited. The pH of the aqueous solution of the compound is not particularly limited, but is preferably 7 or less because the efficiency of introducing a phosphate group is high. Although pH 3-7 is especially preferable from a viewpoint of suppressing hydrolysis of a fiber, it is not specifically limited.

  When a compound having a carboxylic acid-derived group is used as the compound that reacts with the fiber raw material, it is not particularly limited. From the group consisting of a compound having a carboxy group, an acid anhydride of a compound having a carboxy group, and derivatives thereof. At least one selected.

  The compound having a carboxy group is not particularly limited, and examples thereof include dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid and itaconic acid, and tricarboxylic acid compounds such as citric acid and aconitic acid. .

  The acid anhydride of the compound having a carboxy group is not particularly limited, and examples thereof include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. It is done.

  Although it does not specifically limit as a derivative | guide_body of the compound which has a carboxy group, The derivative of the acid anhydride of the compound which has a carboxy group and the acid anhydride imidation of a compound which has a carboxy group are mentioned. The acid anhydride imidized compound having a carboxy group is not particularly limited, and examples thereof include imidized dicarboxylic acid compounds such as maleimide, succinimide, and phthalimide.

  The acid anhydride derivative of the compound having a carboxy group is not particularly limited. For example, at least some of the hydrogen atoms of the acid anhydride of the compound having a carboxy group such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride are substituted (eg, alkyl group, phenyl group, etc.) ) Are substituted.

  Among the compounds having a group derived from a carboxylic acid, maleic anhydride, succinic anhydride, and phthalic anhydride are preferred because they are easily applied industrially and easily gasified, but are not particularly limited.

  When a compound having a group derived from sulfuric acid is used as the compound that reacts with the fiber raw material, it is not particularly limited, but it is at least one selected from the group consisting of sulfuric anhydride, sulfuric acid and salts and esters thereof. Among these, sulfuric acid is preferred, but is not particularly limited because it is low in cost and can further improve the refinement (defibration) efficiency by introducing a sulfate group into the fiber raw material.

  In the case of introducing a cationic substituent, examples of the compound that reacts with the fiber raw material include compounds having a group derived from an onium salt such as an ammonium salt, a phosphonium salt, and a sulfonium salt. Specific examples include compounds having a group containing ammonium, phosphonium, sulfonium such as primary ammonium salt, secondary ammonium salt, tertiary ammonium salt, and quaternary ammonium salt. From the viewpoint of easy handling and reactivity with fibers, groups derived from quaternary ammonium salts and groups derived from phosphonium salts can be mentioned. The introduction amount of the cationic substituent can be measured using, for example, elemental analysis.

In this embodiment, for example, a cationic substituent can be introduced into the fiber raw material by adding a cationizing agent and an alkali compound to the fiber raw material and causing the fiber raw material to react. As the cationizing agent, one having a quaternary ammonium group and a group that reacts with a hydroxy group of cellulose can be used. Examples of the group that reacts with the hydroxy group of cellulose include an epoxy group, a functional group having a halohydrin structure, a vinyl group, and a halogen group.
Specific examples of the cationizing agent include glycidyltrialkylammonium halides such as glycidyltrimethylammonium chloride and 3-chloro-2-hydroxypropyltrimethylammonium chloride or halohydrin type compounds thereof.

  The alkali compound used in the cationization step contributes to the promotion of the cationization reaction. The alkali compound may be an inorganic alkali compound or an organic alkali compound.

Examples of inorganic alkali compounds include alkali metal hydroxides or alkaline earth metal hydroxides, alkali metal carbonates or alkaline earth metal carbonates, alkali metal phosphates or alkaline earth metal phosphoric acids. Salt.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the alkaline earth metal hydroxide include calcium hydroxide.
Examples of the alkali metal carbonate include lithium carbonate, lithium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium carbonate, and sodium hydrogen carbonate. Examples of the alkaline earth metal carbonate include calcium carbonate.
Examples of the alkali metal phosphate include lithium phosphate, potassium phosphate, trisodium phosphate, and disodium hydrogen phosphate. Examples of alkaline earth metal phosphates include calcium phosphate and calcium hydrogen phosphate.

Organic alkali compounds include ammonia, aliphatic amines, aromatic amines, aliphatic ammoniums, aromatic ammoniums, heterocyclic compounds and their hydroxides, carbonates, phosphates, etc. Is mentioned.
Ammonia, hydrazine, methylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, butylamine, diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane;
Cyclohexylamine, aniline, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide;
Pyridine, N, N-dimethyl-4-aminopyridine;
Ammonium carbonate, ammonium hydrogen carbonate, di-ammonium hydrogen phosphate, and the like.
The said alkali compound may be single 1 type, and may combine 2 or more types.

  Among the above alkali compounds, sodium hydroxide and potassium hydroxide are preferable because the cationization reaction is more likely to occur and the cost is low. Although the quantity of an alkali compound changes according to the kind of alkali compound, it shall be in the range of 1-10 mass% with respect to a pulp absolute dry mass, for example.

  Since the cationizing agent and the alkali compound can be easily added to the pulp, it is preferable to form a solution. The solvent used for the solution may be either water or an organic solvent, but a polar solvent (polar organic solvent such as water or alcohol) is preferable, and an aqueous solvent containing at least water is more preferable.

  In this production method, it is preferable that the solvent substance amount per 1 g of the pulp dry mass at the start of the cationization reaction is 5 to 150 mmol. The substance amount of the solvent is more preferably 5 to 80 mmol, and further preferably 5 to 60 mmol. In order to bring the pulp content during the cationization reaction into the above range, for example, a pulp having a high content (that is, having a low water content) may be used. Moreover, it is preferable to reduce the amount of solvent contained in the solution of the cationizing agent and the alkali compound.

  The reaction temperature in the cationization step is preferably in the range of 20 to 200 ° C, more preferably in the range of 40 to 100 ° C. If the reaction temperature is not less than the lower limit, sufficient reactivity can be obtained, and if the reaction temperature is not more than the upper limit, the reaction can be easily controlled. In addition, there is an effect of suppressing coloring of the pulp after the reaction. The time of the cationization reaction varies depending on the type of pulp and cationizing agent, pulp content, reaction temperature, etc., but is usually in the range of 0.5 to 3 hours.

  The cationization reaction may be performed in a closed system or an open system. Further, the solvent may be evaporated during the reaction, and the amount of the solvent substance per 1 g of the pulp dry mass at the end of the reaction may be lower than that at the start of the reaction.

  By introducing an ionic substituent into the fiber raw material, the dispersibility of the fiber in the solution is improved, and the fibrillation efficiency can be increased.

<Refining treatment of fibrous cellulose>
The fine fibrous cellulose slurry can be produced by subjecting the fibrous cellulose to a refinement (defibration) treatment.

In the refining treatment, fibrous cellulose is dispersed in a solvent.
Specific examples of the solvent include water, an organic solvent alone, and a mixture of water and an organic solvent. The organic solvent is not particularly limited as long as the intended dielectric constant can be secured. For example, alcohols, polyhydric alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc) and the like can be mentioned. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, and tbutyl alcohol. Examples of polyhydric alcohols include ethylene glycol and glycerin. Examples of ketones include acetone and methyl ethyl ketone. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and ethylene glycol mono t-butyl ether. Only one organic solvent may be used, or two or more organic solvents may be used. Among the above, the solvent is preferably water.

  The dispersion concentration of the fibrous cellulose in the solvent is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass. This is because if the dispersion concentration is 0.1% by mass or more, the efficiency of the defibrating process is improved, and if it is 20% by mass or less, blockage in the defibrating apparatus can be prevented.

  The defibrating apparatus is not particularly limited. Examples include a high-speed defibrator, a grinder (stone mortar-type pulverizer), a high-pressure homogenizer, an ultra-high-pressure homogenizer, a CLEARMIX, a high-pressure collision-type pulverizer, a ball mill, a bead mill, a disk refiner, and a conical refiner. In addition, a wet pulverizing apparatus such as a twin-screw kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, and a beater can be used as appropriate.

  By the refining treatment, a fine fibrous cellulose slurry is obtained. Although the average fiber width of the obtained fine fibrous cellulose is not specifically limited, For example, it can be set to 1-1000 nm, Preferably it is 2-1000 nm, More preferably, it is 2-500 nm, More preferably, it is 3-100 nm. When the average fiber width of the fine fibers is 1 nm or more, dissolution of molecules in water is suppressed, and thus physical properties (strength, rigidity, dimensional stability) as the fine fibers are sufficiently expressed. On the other hand, when the average fiber width is 1000 nm or less, the features (high transparency, high elastic modulus, low linear expansion coefficient, flexibility) as fine fibers are easily exhibited. The fine fibrous cellulose is monofilamentous cellulose having a fiber width of 1000 nm or less, for example.

  The fine fibrous cellulose dispersion may contain fibrous cellulose (also referred to as coarse fibrous cellulose) having a fiber width exceeding 1000 nm (1 μm). Although it will not specifically limit if the fiber width of coarse fibrous cellulose is larger than 1 micrometer, Preferably it is 5 micrometers or more, More preferably, it is 10 micrometers or more. The coarse fibrous cellulose includes fibrous cellulose having a fiber width exceeding 1000 nm and having a branch-like portion having a width of 1000 nm or less on the surface thereof.

  The average fiber width is measured as follows. A fine fiber-containing slurry having a concentration of 0.05 to 0.1% by mass is prepared, and the slurry is cast on a carbon film-coated grid subjected to a hydrophilization treatment to obtain a sample for TEM observation. When wide fibers are included, an SEM image of the surface cast on glass may be observed. Observation with an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 times, 20000 times, or 50000 times, depending on the width of the constituent fibers. However, the sample, observation conditions, and magnification are adjusted to satisfy the following conditions.

(1) One straight line X is drawn at an arbitrary location in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y perpendicular to the straight line is drawn in the same image, and 20 or more fibers intersect the straight line Y.
The width of the fiber that intersects with the straight line X and the straight line Y is visually read from the observation image that satisfies the above conditions. In this way, at least three sets of images of the surface portion that do not overlap each other are observed, and the width of the fiber intersecting with the straight line X and the straight line Y is read for each image. Thus, at least 20 × 2 × 3 = 120 fiber widths are read. The average fiber width is an average value of the fiber widths read in this way.

The fiber length of the fine fibrous cellulose is not particularly limited, but is preferably 0.1 μm or more. If the fiber length is 0.1 μm or more, it is preferable in that the tear strength of the sheet is sufficient when a sheet described later is manufactured. The fiber length can be obtained by image analysis of TEM, SEM, or AFM. The said fiber length is a fiber length which occupies 30 mass% or more of a fine fiber.
The fiber length of the coarse fibrous cellulose is not particularly limited, but is preferably 10 μm or more.

  The axial ratio of fibers (fiber length / fiber width) is not particularly limited, but is preferably in the range of 20 to 10,000. An axial ratio of 20 or more is preferable in that a fine fiber-containing sheet can be easily formed. An axial ratio of 10,000 or less is preferable in that the slurry viscosity is lowered.

  By the refining treatment, a fine fibrous cellulose slurry is obtained. The density | concentration of a fine fibrous cellulose here is 0.1-20 mass%, for example, 0.2-10 mass% may be sufficient, and 0.5-10 mass% may be sufficient.

<Dehydration>
By subjecting the fine fibrous cellulose slurry obtained above to a dehydration treatment, a fine fibrous cellulose-containing material having a content of fine fibrous cellulose according to the present invention of 5% by mass or more can be prepared. That is, according to the present invention, a step of gelling a diluted solution containing fine fibrous cellulose, a step of obtaining a concentrate containing fine fibrous cellulose from the gelled product obtained above, and a step of heating the concentrate The manufacturing method of the fine fibrous cellulose containing material of this invention containing this is also provided.

  The above gelation step can be carried out by adding a concentrating agent or a solvent to a diluent containing fine fibrous cellulose, but is not particularly limited. Although the process of obtaining the concentrate containing fine fibrous cellulose from a gelled material can be performed by pressing after filtering a gelled material, it is not specifically limited. The step of heating the concentrate can be performed by heating in an oven or the like, but is not particularly limited.

Although it does not specifically limit as a method of a dehydration process, For example, the following method can be mentioned.
(1) A concentrate is added to a dilute solution containing fine fibrous cellulose to form a gel, and after filtration, it is pressed to obtain a concentrate. The concentrate is treated with acid and then with alkali to obtain a concentrate. The fine fibrous cellulose-containing material of the present invention can be obtained by adding a solvent to the concentrate and filtering to obtain the concentrate, and heating the obtained concentrate in an oven or the like.

(2) A concentrate is added to a dilute solution containing fine fibrous cellulose to gelate, and after filtration, the concentrate is obtained by pressing. By heating the obtained concentrate in an oven or the like, the fine fibrous cellulose-containing material of the present invention can be obtained.

(3) A concentrate is added to a dilute solution containing fine fibrous cellulose to cause gelation, and after filtration, the concentrate is obtained by pressing. The concentrate is treated with alkali to obtain a concentrate. A solvent is added to the concentrate and filtered to obtain a concentrate. The step of adding a solvent and filtering to obtain a concentrate may be performed twice or more. By heating the obtained concentrate in an oven or the like, the fine fibrous cellulose-containing material of the present invention can be obtained.

(4) A solvent is added to a diluent containing fine fibrous cellulose to cause gelation, and a residue is obtained by filtration. The solvent is added again to the residue, and the residue is obtained by filtration. From the viewpoint of improving the dispersibility of the fine particles, for example, the above-described solvent addition and filtration operations are preferably performed twice or more, and more preferably three or more times. By heating the obtained filtration residue in an oven or the like, the fine fibrous cellulose-containing material of the present invention can be obtained.

  Examples of the concentrating agent include acids, alkalis, polyvalent metal salts, cationic surfactants, anionic surfactants, cationic polymer flocculants, and anionic polymer flocculants. Among these, the concentration agent is preferably a polyvalent metal salt. Specific examples of the polyvalent metal salt will be described later in this specification.

Although it is preferable to perform a filtration treatment after adding the concentration agent, there is no particular limitation. Moreover, although it is preferable to perform a compression process after a filtration process process, it is not specifically limited. By providing the compression step, the water content in the concentrate can be adjusted to a preferred range.
As a pressing device, a general press device such as a belt press, a screw press, or a filter press can be used, and the device is not particularly limited.
The filter medium to be used is not particularly limited, but stainless steel, filter paper, polypropylene, nylon, polyethylene, polyester and the like can be used. Since an acid may be used, polypropylene is preferable.
The lower the air permeability of the filter medium, the higher the yield. Therefore, it is 30 cm 3 / cm 2 · sec or less, more preferably 10 cm 3 / cm 2 · sec or less, and further preferably 1 cm 3 / cm 2 · sec or less.
If the concentration of the raw material used for the pressing process is low, the dehydrating filtrate increases and the dehydrating process takes a long time. Therefore, it is 0.5% or more, more preferably 1% or more, more preferably 2% or more. .
The pressure at the time of pressing is 0.2 MPa or more, more preferably 0.4 MPa or more.

  A step of treating the concentrate obtained above with an acid and / or a step of treating with an alkali can also be provided. The step of treating with an acid is preferably provided before and after the filtration treatment step, and is preferably provided after the filtration treatment step.

  The acid that can be used in the step of treating with an acid will be described later in this specification. Specifically, it is preferable to immerse the concentrate obtained in the above-described step in an acid solution containing an acid. Although the density | concentration of the acidic liquid to be used is not specifically limited, 10 mass% or less is preferable, More preferably, it is 5 mass% or less, More preferably, it is 1 mass% or less. By setting the concentration of the acidic liquid in the above range, deterioration due to decomposition of cellulose can be suppressed.

  The alkali that can be used in the step of treating with an alkali will be described later in this specification. Specifically, it is preferable to immerse the concentrate obtained in the above-described step or the acid-treated concentrate in an alkaline solution containing an alkali. Although the density | concentration of the alkaline liquid to be used is not specifically limited, 10 mass% or less is preferable, More preferably, it is 5 mass% or less, More preferably, it is 1 mass% or less. By setting the concentration of the alkaline liquid in the above range, deterioration due to decomposition of cellulose can be suppressed.

  It is preferable to perform filtration after the step of treating with an acid and the step of treating with an alkali. In this filtration treatment step, a compression step may be further performed.

  In the present invention, a drying step may be further provided. The drying step is preferably an oven drying step, and for example, drying is preferably performed for 1 to 60 minutes in an oven set to 30 to 70 ° C.

<Fine fibrous cellulose-containing material>
The fine fibrous cellulose-containing material of the present invention is a fine fibrous cellulose-containing material in which the content of fine fibrous cellulose is 5% by mass or more, and the following sample satisfies the following conditions A and B: Cellulose-containing material.
Condition A: The viscosity measured at 3 rpm and 25 ° C. using a B-type viscometer is 2800 mPa · s or more.
Condition B: The haze value is 10% or more and 50% or less.
However, the sample is a sample in which the fine fibrous cellulose-containing material is added to pure water so that the solid content concentration is 0.4% by mass, and stirred with a disperser at 1500 rpm for 5 minutes. .

  In the present invention, the content of fine fibrous cellulose may be 5% by mass or more, and the upper limit is not particularly limited, but preferably the content of fine fibrous cellulose is 95% by mass or less. The content of the fine fibrous cellulose is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more. The content of fine fibrous cellulose may be 30% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more.

A B-type viscometer was added to a sample in which the fine fibrous cellulose-containing material of the present invention was added to pure water so as to have a solid content concentration of 0.4% by mass and stirred with a disperser at 1500 rpm for 5 minutes. Viscosity measured at 3 rpm and 25 ° C. is 2800 mPa · s or more. The upper limit of the viscosity is not particularly limited, but is preferably 30000 mPa · s or less, more preferably 25000 mPa · s or less, more preferably 22000 mPa · s or less, more preferably 21000 mPa · s or less, and further preferably 20000 mPa · s or less. The viscosity may be 3000 mPa · s or more, 5000 mPa · s or more, 8000 Pa · s or more, or 10,000 mPa · s or more.
The disperser is not particularly limited as long as it is a general disperser, but a stirrer such as a homomixer or a three-one motor is used. The same applies to the haze measurement described below.

  The haze value of a sample in which the fine fibrous cellulose-containing material of the present invention was added to pure water so that the solid content concentration was 0.4% by mass and stirred at 1500 rpm for 5 minutes with a disperser was 10%. It is 50% or less. The lower limit of the haze value is preferably 12% or more, more preferably 14% or more, and further preferably 15% or more, but is not particularly limited. The upper limit of the haze value is preferably 45% or less, more preferably 40% or less, still more preferably 35% or less, and further preferably 30% or less, but is not particularly limited.

  The present invention is characterized in that a sample prepared under a predetermined condition using a fine fibrous cellulose-containing material is controlled so as to satisfy both of the above conditions A and B. Thereby, it succeeded in improving the dispersibility of the microparticles | fine-particles in the aqueous medium containing a fine fibrous cellulose.

  In the above dehydration treatment, when an organic solvent is used as a solvent, the fine fibrous cellulose-containing material of the present invention obtained by the treatment may further contain an organic solvent. Moreover, when water is used as a solvent, the fine fibrous cellulose-containing material of the present invention obtained by the above treatment may further contain water.

  Examples of the solvent used in the dehydration treatment include an organic solvent or a mixture of an organic solvent and water. Examples of the organic solvent include alcohols, polyhydric alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and the like. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butyl alcohol. Examples of polyhydric alcohols include ethylene glycol and glycerin. Examples of ketones include acetone and methyl ethyl ketone. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and ethylene glycol mono t-butyl ether. Only one organic solvent may be used, or two or more organic solvents may be used. Among the above, the solvent is preferably alcohols or a mixture of alcohols and water. The solvent is more preferably isopropyl alcohol or a mixture of isopropyl alcohol and water.

  When the fine fibrous cellulose-containing product of the present invention contains alcohols and water, the mass ratio of the content of alcohols and water is preferably 1/5 to 5/1, more preferably Although it is 1/3 to 1/1, it is not particularly limited. The alcohol is preferably isopropyl alcohol.

In the above dehydration treatment, when a concentration agent is used, the fine fibrous cellulose-containing material of the present invention obtained by the above treatment may further contain a concentration agent.
Examples of the thickener include polyvalent metal salts, cationic surfactants, anionic surfactants, cationic polymer flocculants, and anionic polymer flocculants, but are not particularly limited. When a polyvalent metal salt is used as the thickener, the fine fibrous cellulose-containing material of the present invention may further contain a polyvalent metal. Examples of the polyvalent metal include aluminum, calcium, and magnesium, but are not particularly limited. Examples of the polyvalent metal salt include, but are not limited to, aluminum sulfate (sulfate band), polyaluminum chloride, calcium chloride, aluminum chloride, magnesium chloride, calcium sulfate, and magnesium sulfate.

  When the fine fibrous cellulose-containing material of the present invention contains a polyvalent metal, the content is not particularly limited, but is preferably 5 ppm to 1000 ppm, more preferably 10 ppm to 100 ppm. In the fine fibrous cellulose-containing material, the content of the polyvalent metal can be less than 5 ppm, and an embodiment that does not include the polyvalent metal can be employed.

In the above dehydration treatment, when an acid is used, the fine fibrous cellulose-containing material of the present invention obtained by the treatment may further contain an acid.
As the acid, for example, inorganic acid, sulfonic acid, carboxylic acid and the like can be used. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, phosphoric acid, boric acid and the like. Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, and the like. Examples of the carboxylic acid include formic acid, acetic acid, citric acid, gluconic acid, lactic acid, oxalic acid, and tartaric acid.

  When the fine fibrous cellulose-containing product of the present invention contains an acid, the content is not particularly limited, but may be 0.01% by mass or more and 0.14% by mass or less with respect to the mass of the fine fibrous cellulose. preferable. In addition, in a fine fibrous cellulose containing material, content of an acid can also be made into less than 0.01 mass%, and it is also possible to employ | adopt the aspect which does not contain an acid.

In the above dehydration treatment, when an alkali is used, the fine fibrous cellulose-containing material of the present invention obtained by the treatment may further contain an alkali.
The alkali may be either an inorganic alkali or an organic alkali.
Examples of the inorganic alkali include, but are not limited to, the following. Lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium carbonate, lithium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, calcium carbonate, calcium phosphate, calcium hydrogen phosphate.
Examples of the organic alkali include the following, but are not particularly limited.
Ammonia, hydrazine, methylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, butylamine, diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane;
Cyclohexylamine, aniline, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide;
Pyridine, N, N-dimethyl-4-aminopyridine and the like.

  When the fine fibrous cellulose-containing product of the present invention contains an alkali, the content is not particularly limited, but is preferably 0.01% by mass or more and 2% by mass or less with respect to the mass of the fine fibrous cellulose. The content is more preferably 0.2% by mass or less, and further preferably 0.02% by mass or less. In addition, in a fine fibrous cellulose containing material, content of an alkali can also be made into less than 0.01 mass%, and it is also possible to employ | adopt the aspect which does not contain an alkali.

  In the fine fibrous cellulose-containing product of the present invention, when the fine fibrous cellulose is anion-modified, it is desirable that the counter ion of the functional group is a sodium ion. By using sodium ions, the fine fibrous celluloses repel each other and are less likely to cause aggregation.

  Although the form of the fine fibrous cellulose containing material of this invention is not specifically limited, Preferably it is a granular form. The term “powdered granular” refers to a powdered substance and / or a granular substance. A powdery substance is one that is smaller than a granular substance. In general, the powdery substance refers to fine particles having a particle diameter of 1 nm or more and less than 0.1 mm, and the granular substance refers to particles having a particle diameter of 0.1 to 10 mm, but is not particularly limited. In addition, the granular form is not necessarily spherical. The particle diameter of the granular material in the present specification can be measured by the following method. The particle diameter of the granular material in this specification shall be the value measured using the laser diffraction scattering type particle size distribution measuring apparatus (Microtrac3300EXII, Nikkiso Co., Ltd.).

The fine fibrous cellulose-containing material of the present invention preferably has the following sample pH of 7 or more and 11 or less, more preferably the sample sample pH of 8 or more and 10.5 or less, but is not particularly limited. The sample is a sample in which the fine fibrous cellulose-containing material is added to pure water so that the solid content concentration is 0.4% by mass, and stirred with a disperser at 1500 rpm for 5 minutes.
When the pH of the sample is 7 or more, the counter ion of the functional group of the fine fibrous cellulose becomes sodium ion, and the fine fibrous cellulose repels electrostatically and is easily dispersed in the solvent.
By controlling the pH of the sample to 11 or less, the alkali concentration in the system can be suppressed, and the dispersibility of the fine fibrous cellulose in the solvent due to the electrostatic repulsion can be improved.

<Redispersion of fine fibrous cellulose-containing material>
A fine fibrous cellulose redispersed product can be obtained by resuspending the fine fibrous cellulose-containing material of the present invention in a solvent.

  The kind of solvent used in order to obtain a fine fibrous cellulose containing material is not specifically limited. Specific examples of the solvent include water, an organic solvent alone, and a mixture of water and an organic solvent. Examples of the organic solvent include alcohols, polyhydric alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and the like. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butyl alcohol. Examples of polyhydric alcohols include ethylene glycol and glycerin. Examples of ketones include acetone and methyl ethyl ketone. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and ethylene glycol mono t-butyl ether. Only one organic solvent may be used, or two or more organic solvents may be used. Among the above, the solvent is preferably a mixture of alcohols and water, a mixture of ethers and water, or a mixture of DMSO and water.

  Redispersion of the fine fibrous cellulose can be performed by a conventional method. For example, the step of preparing a liquid containing fine fibrous cellulose by adding the above-described solvent to the fine fibrous cellulose-containing material of the present invention, and the fine fibrous cellulose in the liquid containing this fine fibrous cellulose Redispersion can be performed by the step of dispersing.

  When preparing a liquid containing fine fibrous cellulose by adding a solvent to the fine fibrous cellulose-containing material of the present invention, the content of fine fibrous cellulose is 0.1% by mass to 10% by mass with respect to the total liquid. It is preferable to make it. The fine fibrous cellulose content is more preferably 0.2% by mass to 3% by mass with respect to the fine fibrous cellulose-containing liquid. If the content is 0.1% by mass or more, the dispersion stability of the fine fibrous cellulose becomes high, and if the content is 10% by mass or less, the viscosity of the fine fibrous cellulose does not become too high and handling is possible. It becomes relatively easy. The fine fibrous cellulose content can be adjusted by the addition amount of the solvent, and the fine fibrous cellulose content decreases as the addition amount of the solvent increases.

  As the dispersing device used in the step of dispersing the fine fibrous cellulose, the same device as the defibrating treatment device described in the above <Fibrous cellulose refining treatment> can be used.

  The fine fibrous cellulose redispersion obtained as described above has a fine fibrous cellulose concentration of preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and more preferably 1% by mass. % Or more, and more preferably 3% by mass or more. The upper limit of the concentration of the fine fibrous cellulose is not particularly limited, but is generally 10% by mass or less. By making the density | concentration of a fine fibrous cellulose within said range, the handling in the case of coating becomes favorable and it is excellent in dispersion stability. The dispersibility can be evaluated based on whether or not precipitation is observed by performing a dispersion treatment with a homodisper or the like and visually observing the liquid immediately after that.

<Other ingredients>
The fine fibrous cellulose-containing material of the present invention may contain a surfactant. By including the surfactant, the surface tension is reduced, the wettability with respect to the process substrate can be increased, and the fine fibrous cellulose-containing sheet can be formed more easily.

  As the surfactant, a nonionic surfactant, an anionic surfactant, or a cationic surfactant can be used. When cellulose is anionic, nonionic surfactants and anionic surfactants are preferred. When cellulose is cationic, nonionic surfactants and cationic surfactants are preferred.

  The fine fibrous cellulose-containing material of the present invention can also be prepared by mixing at least one kind of fibers other than fine fibrous cellulose (hereinafter referred to as “additional fibers”). Examples of the additional fiber include inorganic fiber, organic fiber, synthetic fiber, semi-synthetic fiber, and recycled fiber, but are not particularly limited. Examples of inorganic fibers include, but are not limited to, glass fibers, rock fibers, and metal fibers. Examples of organic fibers include, but are not limited to, fibers derived from natural products such as cellulose, carbon fibers, pulp, chitin, and chitosan. Examples of synthetic fibers include, but are not limited to, nylon, vinylon, vinylidene, polyester, polyolefin (eg, polyethylene, polypropylene, etc.), polyurethane, acrylic, polyvinyl chloride, aramid, and the like. Semi-synthetic fibers include but are not limited to acetate, triacetate, promix and the like. Examples of the regenerated fiber include, but are not limited to, rayon, cupra, polynosic rayon, lyocell, and tencel. The additional fiber can be subjected to treatment such as chemical treatment and defibrating treatment as necessary. When the additional fiber is subjected to chemical treatment, defibrating treatment, etc., it can be mixed with fine fibers and then subjected to chemical treatment, defibrating treatment, etc., and the additional fiber can be chemically treated, defibrated. It can also be mixed with fine fibers after being treated. When the additional fiber is mixed, the addition amount of the additional fiber in the total amount of the fine fiber and the additional fiber is not particularly limited, but is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30%. It is below mass%. Especially preferably, it is 20 mass% or less.

  A hydrophilic polymer may be added to the fine fibrous cellulose-containing material of the present invention. The hydrophilic polymer is not particularly limited. Examples thereof include polyethylene glycol, cellulose derivatives (hydroxyethyl cellulose, carboxyethyl cellulose, carboxymethyl cellulose, etc.), casein, dextrin, starch, modified starch and the like. Moreover, polyvinyl alcohol and modified polyvinyl alcohol (such as acetoacetylated polyvinyl alcohol) can be mentioned. Furthermore, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylates, polyacrylamide, alkyl acrylate ester copolymer, urethane copolymer, and the like can be given.

  A hydrophilic low molecular weight compound can also be used in place of the hydrophilic polymer. The hydrophilic low molecular compound is not particularly limited. Examples include glycerin, erythritol, xylitol, sorbitol, galactitol, mannitol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol and the like. The addition amount in the case of adding a hydrophilic polymer or a hydrophilic low molecular compound is not particularly limited. For example, with respect to 100 mass parts of solid content of a fine fiber, it is 1-200 mass parts, Preferably it is 1-150 mass parts, More preferably, it is 2-120 mass parts, More preferably, it is 3-100 mass parts.

<Application>
The use of the fine fibrous cellulose-containing material according to the present invention is not particularly limited. As an example, it can form into a film using a fine fibrous cellulose redispersion slurry, and can be used as various films. As another example, the fine fibrous cellulose redispersed slurry can be used as a thickener in various applications (for example, additives to foods, cosmetics, cement, paints, inks, etc.). Furthermore, it can be used as a reinforcing material by mixing with resin or emulsion.

  The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Production Example 1: Preparation of CNF1 A phosphorylating reagent was prepared by dissolving 100 g of urea, 55.3 g of sodium dihydrogen phosphate dihydrate, and 41.3 g of disodium hydrogen phosphate in 109 g of water.
The dried softwood bleached kraft pulp paper was processed with a cutter mill and a pin mill to form cotton-like fibers. 100 g of this cotton-like fiber was taken in an absolutely dry mass, and the phosphorylating reagent was sprayed evenly with a spray, and then kneaded by hand to obtain a chemical-impregnated pulp.
The obtained chemical-impregnated pulp was heat-treated for 120 minutes in a blower dryer with a damper heated to 140 ° C. to obtain phosphorylated pulp.
100 g of the obtained phosphorylated pulp was collected by pulp mass, poured with 10 L of ion exchange water, stirred and dispersed uniformly, and then subjected to filtration and dehydration to obtain a dehydrated sheet twice. The dehydrated sheet obtained here is referred to as dehydrated sheet A.

  Next, the dehydrated sheet obtained above was diluted with 10 L of ion exchange water, and 1N aqueous sodium hydroxide solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 to 13.

Thereafter, the pulp slurry was dehydrated to obtain a dehydrated sheet, and 10 L of ion-exchanged water was poured, and the mixture was stirred and dispersed uniformly, followed by filtration and dehydration to obtain a dehydrated sheet twice.
Ion exchange water was added to prepare a 2% by mass slurry. The slurry was passed through a single disc refiner with a clearance set at 100 μm three times to obtain CNF1.

-Introduced Substrate Amount For the above dehydrated sheet A, the amount of phosphate groups introduced was measured by the following titration method.
[Measurement of Substituent Introduced Amount (Phosphate Group Introduced Amount)]
The amount of substituent introduction is the amount of phosphate groups introduced into the fiber material, and the larger this value, the more phosphate groups are introduced. The amount of substituent introduced was measured by diluting the target fine fibrous cellulose with ion-exchanged water so that the content was 0.2% by mass, and then treating with ion-exchange resin and titration with alkali. In the treatment with an ion exchange resin, 1/10 by volume of a strongly acidic ion exchange resin (Amberjet 1024; Organo Co., Ltd., conditioned) is added to the 0.2 mass% fibrous cellulose-containing slurry and shaken for 1 hour. Went. Thereafter, the mixture was poured onto a mesh having an opening of 90 μm to separate the resin and the slurry. In titration using an alkali, a change in the value of electrical conductivity exhibited by the slurry was measured while adding a 0.1N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry after ion exchange. That is, the alkali amount (mmol) required in the first region of the curve shown in FIG. 1 was divided by the solid content (g) in the titration target slurry to obtain the substituent introduction amount (mmol / g).

Production Examples 2-8: Preparation of CNFs 2-8 In Production Example 1, instead of passing the single disc refiner three times, the single disc refiner was used four times, five times, six times, seven times, eight times, nine times, or CNFs 2-8 were prepared by passing 10 times, respectively.

Production Examples 9 and 10: CNFs 9 and 10
In Production Example 1, the heat treatment time by the blower dryer was changed from 120 minutes to 80 minutes, and instead of passing the single disk refiner three times, the single disk refiner was passed five times or ten times, thereby making the CNFs 9 and 10 respectively. Prepared.

Production Examples 11 to 18: Preparation of CNFs 11 to 18 In Production Example 1, CNF 11 was prepared by changing the heat treatment time by a blow dryer from 120 minutes to 160 minutes.
In Production Example 1, the heat treatment time by the blower dryer was changed from 120 minutes to 160 minutes. Further, in Production Example 1, instead of passing the single disk refiner three times, the single disk refiner was passed four times, five times, six times, seven times, eight times, nine times, or ten times. By the above, CNF12-CNF18 were prepared, respectively.

Production Example 19: Preparation of CNF19 Undried softwood bleached kraft pulp equivalent to a dry mass of 200 g, 2.5 g of TEMPO, and 25 g of sodium bromide were dispersed in 1500 ml of water. Then, 13 mass% sodium hypochlorite aqueous solution was added so that the quantity of sodium hypochlorite might be set to 5.0 mmol with respect to 1.0 g of pulp, and reaction was started. During the reaction, a 0.5 M aqueous sodium hydroxide solution was added dropwise to maintain the pH at 10 to 11, and the reaction was terminated when no change in pH was observed.

  Thereafter, the pulp slurry was dehydrated to obtain a dehydrated sheet, and then 10 L of ion exchange water was added. Next, the step of stirring and dispersing uniformly and then dewatering by filtration to obtain a dehydrated sheet was repeated twice.

  Ion exchange water was added to prepare a 2% by mass slurry. This slurry was passed 10 times through a single disc refiner with a clearance set at 100 μm to obtain CNF19.

Production Example 20: Preparation of CNF20 Except that a 13% by mass aqueous sodium hypochlorite solution was added to 1.0 g of pulp so that the amount of sodium hypochlorite was 8.0 mmol, and the reaction was started. CNF20 was prepared in the same manner as in Preparation Example 19 (CNF19).

Production Example 21: Preparation of CNF21 In Production Example 1, the heat treatment time by the blast dryer was changed from 120 minutes to 160 minutes, and the slurry was subjected to a wet atomization apparatus ("Ultimizer" manufactured by Sugino Machine Co., Ltd.) at a pressure of 245 MPa. CNF21 was prepared by passing 10 times.

<Measurement of fiber width>
The fiber widths of CNF1 to CNF21 were measured by the following method.
The supernatant liquid of the cellulose suspension was diluted with water to a concentration of 0.01 to 0.1% by mass and dropped onto a carbon grid membrane subjected to a hydrophilic treatment. After drying, it was stained with uranyl acetate and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.).
Moreover, the supernatant liquid of the cellulose suspension was diluted with water to a concentration of 0.01 to 0.1% by mass and dropped onto a slide glass. A cover glass was put on and observed with a digital microscope (Hirox, KH-7700).

  From the above, it was confirmed that CNF1 to CNF21 contain fine fibrous cellulose having an average fiber width of 1000 nm or less. CNFs 1 to 20 also included coarse fibrous cellulose having an average fiber width of more than 1 μm and a fiber length of 10 μm or more.

  The amounts of substituents of CNF1 to CNF21 are shown in Table 1 below.

Example 1
CNF1 was diluted to 0.4% by mass, and 1 g of calcium chloride was added as a concentrating agent to 100 mL of the diluted solution to cause gelation. After filtration, the mixture was pressed with filter paper to obtain a concentrate having a solid content concentration of 21.4% by mass. The concentrate is immersed in 100 mL of 0.1N aqueous hydrochloric acid for 30 minutes, 2 g of isopropanol and 2 g of 6% aqueous sodium hydroxide solution are added, mixed well with a spoon, and filtered to obtain a solid concentration of 23.0% by mass. A concentrate was obtained. 2 g of isopropanol and 2 g of ion-exchanged water were added to the concentrate, mixed well with a spoon, and then filtered to obtain a concentrate having a solid content concentration of 26.7%. The resulting concentrate was placed in an oven set at 60 ° C. and heated for 30 minutes. The solid content concentration of the obtained concentrate was 95% by mass.

(Examples 2 to 18)
A concentrate was prepared in the same manner as in Example 1 except that CNF2-18 was used instead of CNF1. The solid content concentration was 95% by mass.

(Examples 19 to 22)
Using CNF18 instead of CNF1 and performing a concentration operation in the same manner as in Example 1 to prepare a concentrate having a solid content of 22.2% by mass, each was set in an oven set at 60 ° C. for 0 minutes, 5 minutes, Heating was performed for 10 minutes and 15 minutes. Except for the above, the concentrates of Examples 19 to 22 were prepared in the same manner as Example 1. The solid content concentrations of the concentrates of Examples 19 to 22 were 22.2% by mass, 30.1% by mass, 44.3% by mass, and 56.3% by mass, respectively.

(Example 23)
CNF18 was diluted to 0.4% by mass, and 1 g of calcium chloride was added as a concentrating agent to 100 mL of the diluted solution to cause gelation. After filtration, the mixture was squeezed with filter paper to obtain a concentrate having a solid content concentration of 22.4% by mass. The concentrate was immersed in 100 ml of 0.1N aqueous hydrochloric acid for 30 minutes, filtered, placed in an oven set at 60 ° C., and heated for 30 minutes. The solid content concentration of the obtained concentrate was 95% by mass.

(Example 24)
CNF18 was diluted to 0.4% by mass, and 1 g of aluminum chloride was added as a concentrating agent to 100 mL of the diluted solution to cause gelation. After filtration, the mixture was squeezed with filter paper to obtain a concentrate having a solid content concentration of 20.1% by mass. 2 g of isopropanol and 2 g of a 6% aqueous sodium hydroxide solution were added, mixed well with a spoon, and then filtered to obtain a concentrate having a solid content concentration of 22.0% by mass. 2 g of isopropanol and 2 g of ion exchange water were added to the concentrate, mixed well with a spoon, and then filtered to obtain a concentrate with a solid content concentration of 26.9%. 2 g of isopropanol was added to the resulting concentrate and mixed well with a spoonful, followed by filtration to obtain a concentrate with a solid content concentration of 32.4%. Placed in an oven set at 60 ° C. and heated for 15 minutes. The solid content concentration of the obtained concentrate was 95% by mass.

(Examples 25 and 26)
Concentrates of Example 25 and Example 26 were prepared in the same manner as Example 1 except that CNF19 and CNF20 were used instead of CNF1. The solid content concentration of the concentrate of Example 25 was 94.3% by mass, and the solid content concentration of the concentrate of Example 26 was 93.2% by mass.

(Comparative Example 1)
CNF1 was diluted to 0.4 mass%, 100 mL of the diluted solution was poured into a Teflon (registered trademark) petri dish, placed in an oven set at 60 ° C., and heated for 120 minutes. The solid content concentration of the obtained concentrate was 98.7% by mass.

(Comparative Example 2)
It carried out similarly to the comparative example 1 except having made heating time into 40 minutes. The solid content concentration of the obtained concentrate was 24.1% by mass.

(Comparative Example 3)
CNF21 was performed in the same manner as in Comparative Example 1. The solid content concentration of the obtained concentrate was 96.2% by mass.

The following table shows the results of the following measurements and evaluations on the concentrates prepared in each Example and each Comparative Example.

(Measurement of haze value)
Concentrates prepared in each example and each comparative example were added to 100 mL of ion-exchanged water, and the mixture was stirred for 5 minutes at 1500 rpm with a disperser (stirring TK Robotics, manufactured by Tokushu Kika Kogyo Co., Ltd.), 0.4% by mass An aqueous solution (also referred to as a redispersion) was prepared.
The haze of the 0.4 mass% dispersion is placed in a liquid glass cell (manufactured by Fujiwara Seisakusho, MG-40, reverse optical path) with an optical path length of 1 cm. The haze meter (Murakami Color) conforms to JIS standard K7136. Measurement was performed using “HM-150” manufactured by Technical Research Institute. Zero point measurement was performed with ion-exchanged water placed in the glass cell.

(Dispersibility evaluation)
Concentrates prepared in each example and each comparative example were added to 100 mL of ion-exchanged water, and the mixture was stirred for 5 minutes at 1500 rpm with a disperser (stirring TK Robotics, manufactured by Tokushu Kika Kogyo Co., Ltd.), 0.4% by mass An aqueous solution (also referred to as a redispersion) was prepared.
After adding 1.0% by mass of hydrophobized titanium oxide (STV-455, manufactured by Titanium Industry Co., Ltd.) to 100 mL of the above 0.4% by mass aqueous solution, the mixture was stirred for 5 minutes at 4,000 rpm using a homomixer. It left still for 30 minutes and observed whether hydrophobized titanium oxide isolate | separated from an aqueous layer.
A: Hydrophobized titanium oxide is not separated at all, and the uniformity is maintained.
○: Somewhat separated hydrophobized titanium oxide is present, but the uniformity is maintained as a whole.
X: Hydrophobized titanium oxide particles are precipitated or present on the water surface and separated from the aqueous layer.

(viscosity)
Concentrates prepared in each example and each comparative example were added to 100 mL of ion-exchanged water, and the mixture was stirred for 5 minutes at 1500 rpm with a disperser (stirring TK Robotics, manufactured by Tokushu Kika Kogyo Co., Ltd.), 0.4% by mass An aqueous solution (also referred to as a redispersion) was prepared.
The viscosity of the 0.4 mass% aqueous solution was measured at 25 ° C. using a B-type viscometer (manufactured by BLOOKFIELD, analog viscometer T-LVT) at a rotation speed of 3 rpm (3 minutes).

Claims (11)

The content of fine fibrous cellulose is 5% by mass or more, and is a fine fibrous cellulose-containing product that is granular, wherein the fine fibrous cellulose has an ionic substituent of 0.5 to 2.0 mmol / g. Have
Further having a polyvalent metal;
Fine fibrous cellulose-containing material in which the following sample satisfies the following conditions A and B:
Condition A: The viscosity measured at 3 rpm and 25 ° C. using a B-type viscometer is 8000 mPa · s or more.
Condition B: The haze value is 10% or more and 50% or less.
However, the sample is a sample in which the fine fibrous cellulose-containing material is added to pure water so that the solid content concentration is 0.4% by mass, and stirred with a disperser at 1500 rpm for 5 minutes. . The fine fibrous cellulose-containing material according to claim 1, further comprising an organic solvent. The fine fibrous cellulose-containing material according to claim 2, wherein the organic solvent is alcohol. The fine fibrous cellulose-containing material according to claim 2 or 3, wherein the organic solvent is isopropyl alcohol. The fine fibrous cellulose-containing material according to any one of claims 2 to 4, further comprising water. The fine fibrous cellulose-containing product according to any one of claims 1 to 5, further comprising one or more selected from acids and alkalis. Ionic substituent is Ru phosphoric acid group or a carboxyl group der, microfibrous cellulose-containing material according to any one of claims 1 to 6. The fine fibrous cellulose-containing product according to any one of claims 1 to 7, wherein the ionic substituent is a phosphate group. The content of fine fibrous cellulose according to any one of claims 1 to 8 , wherein the content of fine fibrous cellulose is 95% by mass or less. The fine fibrous cellulose-containing product according to any one of claims 1 to 9 , further comprising coarse fibrous cellulose having an average fiber width of greater than 1 µm. The fine fibrous cellulose-containing material according to claim 10 , wherein the fiber length of the coarse fibrous cellulose is 10 µm or more.

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