JP2020105470A - Fibrous cellulose-containing material, fibrous cellulose-containing liquid composition and formed body - Google Patents

Abstract

To provide a fibrous cellulose-containing material that is excellent in re-dispersibility in organic solvent, and, when forming a sheet from re-dispersed slurry of fine fibrous cellulose, that can form a sheet with high tensile modulus.SOLUTION: The present invention relates to a fibrous cellulose-containing material, containing a fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorus oxo acid group or a substituent derived from the phosphorus oxo acid group, and an organic onium ion as a counter ion of a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid group, and in which, setting the first dissociated acid amount in the fibrous cellulose as A1 and the total dissociated acid amount in the fibrous cellulose as A2, the value of A1/A2 is 0.65 or more.SELECTED DRAWING: None

Description

The present invention relates to a fibrous cellulose-containing material, a fibrous cellulose-containing liquid composition and a molded article.

Conventionally, cellulose fibers have been widely used in clothing, absorbent articles, paper products and the like. As cellulose fibers, in addition to fibrous cellulose having a fiber diameter of 10 μm or more and 50 μm or less, fine fibrous cellulose having a fiber diameter of 1 μm or less is known. Fine fibrous cellulose has been attracting attention as a new material, and its uses are diverse. For example, the development of sheets, resin composites and thickeners containing fine fibrous cellulose is under way.

Generally, since fine fibrous cellulose is stably dispersed in an aqueous solvent, it is often provided as an aqueous dispersion and used for various purposes. On the other hand, when the fine fibrous cellulose is mixed with a resin to produce a composite or the like, there is also a desire to use the fine fibrous cellulose mixed with an organic solvent. As a technique to meet such a demand, a technique for producing a fine fibrous cellulose-containing dispersion liquid in which fine fibrous cellulose is dispersed in a dispersion medium containing an organic solvent has been studied.

For example, Patent Document 1 discloses a fine fibrous cellulose composite in which a surfactant is adsorbed on a fine fibrous cellulose having a carboxy group. Here, after micronizing the cellulose fibers in an aqueous solvent, a method of aggregating the fine fibrous cellulose and dispersing it in an organic solvent, or a method of micronizing the cellulose fibers in an organic solvent to obtain fine fibrous cellulose is It is disclosed. Patent Document 2 discloses a fine fibrous cellulose having a phosphate group, which contains an organic onium ion as a counter ion of the phosphate group.

JP, 2011-140738, A International Publication No. 2018/159743

Generally, the relative permittivity of an organic solvent is lower than that of water, and thus it is known that it is difficult to obtain the electrostatic repulsion force required when dispersing fine fibrous cellulose. Therefore, the dispersibility of the fine fibrous cellulose in the organic solvent tends to be insufficient. If the dispersibility of the fine fibrous cellulose is insufficient in the organic solvent, the viscosity of the redispersion slurry in which the fine fibrous cellulose is dispersed may be low. Here, in order to enhance the dispersibility of the fine fibrous cellulose is also considered to introduce a counter ion such as an organic onium ion, in this case, when forming a sheet from a redispersed slurry of fine fibrous cellulose The tensile elastic modulus of the sheet sometimes decreased.

Therefore, the present inventors, in order to solve the problems of such conventional technology, a fibrous cellulose-containing material excellent in redispersibility in an organic solvent, a sheet from a redispersion slurry of fine fibrous cellulose. The study was conducted for the purpose of providing a fibrous cellulose-containing material capable of forming a sheet having a high tensile elastic modulus when formed.

As a result of extensive studies to solve the above problems, the present inventors have found that a fibrous cellulose containing a fine fibrous cellulose having a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid group, and an organic onium ion. In the cellulose-containing material, when the first dissociated acid amount in the fine fibrous cellulose is A1 and the total dissociated acid amount in the fine fibrous cellulose is A2, the value of A1/A2 is 0.65 or more, It was found that a fibrous cellulose-containing material excellent in redispersibility in an organic solvent can be obtained. Further, the present inventors have found that a sheet formed from a redispersed slurry of such a fibrous cellulose-containing material has a high tensile elastic modulus, and completed the present invention.
Specifically, the present invention has the following configurations.

[1] A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorus oxo acid group or a substituent derived from the phosphorus oxo acid group, and an organic onium ion as a counter ion of the phosphorus oxo acid group or the substituent derived from the phosphorus oxo acid group. A fibrous cellulose-containing material containing,
A fibrous cellulose-containing material having a value of A1/A2 of 0.65 or more, where A1 is the first dissociated acid amount in the fibrous cellulose and A2 is the total dissociated acid amount in the fibrous cellulose.
[2] As a counter ion of fibrous cellulose having a fiber width of 1000 nm or less and having a phosphite group or a substituent derived from a phosphite group, and a phosphite group or a substituent derived from a phosphite group A fibrous cellulose-containing material containing an organic onium ion.
[3] The fibrous cellulose-containing material according to [1] or [2], wherein the organic onium ion satisfies at least one condition selected from the following (a) and (b):
(A) contains a hydrocarbon group having 5 or more carbon atoms;
(B) The total carbon number is 17 or more.
[4] The fibrous cellulose-containing material according to any of [1] to [3], wherein the organic onium ion is organic ammonium.
[5] The fibrous cellulose-containing material according to any one of [1] to [4], wherein the content of the fibrous cellulose is 80% by mass or more based on the total mass of the fibrous cellulose-containing material.
[6] A fibrous cellulose-containing liquid composition obtained by mixing the fibrous cellulose-containing material according to any one of [1] to [5] with an organic solvent.
[7] The fibrous cellulose-containing liquid composition according to [6], which further contains a resin component.
[8] A molded product formed from the fibrous cellulose-containing material according to any one of [1] to [5] or the fibrous cellulose-containing liquid composition according to [6] or [7].

According to the present invention, a fibrous cellulose-containing material having excellent redispersibility in an organic solvent, and when a sheet is formed from a redispersion slurry of fine fibrous cellulose, a sheet having a high tensile elastic modulus is formed. The resulting fibrous cellulose-containing material can be obtained.

FIG. 1 is a graph showing the relationship between the dropping amount of NaOH and pH for a slurry containing fibrous cellulose having a phosphorous acid group. FIG. 2 is a graph showing the relationship between the dropping amount of NaOH and the pH for a slurry containing a fibrous cellulose having a carboxy group.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments.

(Containing fibrous cellulose)
A first aspect of the present invention is a pair of a fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid group, and a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid group. A fibrous cellulose-containing material containing an organic onium ion as an ion. Here, when the first dissociated acid amount in the fibrous cellulose is A1 and the total dissociated acid amount in the fibrous cellulose is A2, the value of A1/A2 is 0.65 or more.

The second aspect of the present invention has a fiber width of 1000 nm or less and is derived from a fibrous cellulose having a phosphite group or a substituent derived from a phosphite group and a phosphite group or a phosphite group. The present invention relates to a fibrous cellulose-containing material containing an organic onium ion as a counter ion of a substituent.

Since the fibrous cellulose-containing material of the present invention has the above-mentioned constitution, it is excellent in redispersibility in an organic solvent. Therefore, the redispersion slurry obtained by dispersing the fibrous cellulose-containing material in the organic solvent has a high viscosity. Further, since the fibrous cellulose-containing material is excellent in redispersibility in an organic solvent, the obtained redispersion slurry is also excellent in transparency. Furthermore, since the fibrous cellulose-containing material of the present invention has good dispersibility in an organic solvent, it is possible to reduce energy required when the fibrous cellulose is dispersed in the organic solvent.

Further, since the fibrous cellulose-containing material of the present invention has the above-mentioned constitution, when a sheet is formed from the redispersed slurry, a sheet having a high tensile elastic modulus can be obtained. Conventionally, in order to enhance the dispersibility of the fibrous cellulose-containing material in an organic solvent, it has been considered to contain an organic onium ion as a counter ion such as an anionic group, but in such a case, The tensile modulus tended to decrease. That is, in the prior art, it was difficult to achieve both improvement in dispersibility in an organic solvent and improvement in tensile elastic modulus of the obtained sheet. However, in the present invention, by making the substituents of the fibrous cellulose satisfy the predetermined conditions, even if the fibrous cellulose has an organic onium ion as a counter ion, the fibrous cellulose-containing dispersion in the organic solvent is We succeeded in increasing the tensile elasticity modulus of the obtained sheet at the same time as improving the elasticity.

As described above, since the fibrous cellulose-containing material of the present invention has excellent dispersibility in an organic solvent, the redispersion slurry obtained by dispersing the fibrous cellulose-containing material in the organic solvent has a high viscosity. Here, the viscosity of the redispersion slurry is measured by using a B-type viscometer after allowing the redispersion slurry having a fibrous cellulose concentration of 2.0% by mass to stand at 23° C. for 24 hours. It is the value. At this time, the measurement is performed under the condition of 23° C., and the viscosity when rotated at 3 rpm for 3 minutes is measured. As the B-type viscometer, for example, an analog viscometer T-LVT manufactured by BLOOKFIELD can be used.

The viscosity of the redispersion slurry obtained by dispersing the fibrous cellulose-containing material in an organic solvent depends on the type of the organic solvent as the dispersion medium and the concentration of the fine fibrous cellulose in the dispersion. For example, when the concentration of fine fibrous cellulose in the redispersion slurry is 2.0 mass% and the organic solvent is N-methyl-2-pyrrolidone (NMP), the viscosity of the redispersion slurry is 15,000 mPa·s. It is preferably not less than 30,000 mPa·s, more preferably not less than 30,000 mPa·s, further preferably not less than 40,000 mPa·s, further preferably not less than 50,000 mPa·s, particularly preferably not less than 70,000 mPa·s. .. When the concentration of fine fibrous cellulose in the organic solvent slurry is 4.0% by mass and the organic solvent is toluene, the viscosity of the redispersion slurry is preferably 6500 mPa·s or more, and 7,000 mPa·s. s or more is more preferable, 7500 mPa·s or more is further preferable, 8000 mPa·s or more is further preferable, and 8500 mPa·s or more is particularly preferable. When the concentration of the fine fibrous cellulose in the organic solvent slurry is 2.0% by mass and the organic solvent is methanol, the viscosity of the redispersion slurry is preferably 30,000 mPa·s or more, and 40,000 mPa·s or more. Is more preferable, 50,000 mPa·s or more is more preferable, 60,000 mPa·s or more is further preferable, and 70,000 mPa·s or more is particularly preferable. When the concentration of the fine fibrous cellulose in the organic solvent slurry is 2.0 mass% and the organic solvent is dimethyl sulfoxide (DMSO), the viscosity of the redispersion slurry is preferably 84000 mPa·s or more, It is more preferably 88,000 mPa·s or more, further preferably 92,000 mPa·s or more, further preferably 96,000 mPa·s or more, and particularly preferably 100,000 mPa·s or more.

Since the fibrous cellulose-containing material of the present invention has good dispersibility in an organic solvent, it does not form a precipitate in the dispersion liquid. Therefore, the organic solvent slurry obtained by dispersing fine fibrous cellulose in an organic solvent is highly transparent.

When a sheet is formed from a redispersed slurry obtained by dispersing a fibrous cellulose-containing material in an organic solvent, the sheet has a high tensile elastic modulus. The tensile modulus of elasticity of such a sheet is preferably 4.5 MPa or more, more preferably 5.0 MPa or more, and further preferably 6.0 MPa or more. The tensile modulus of elasticity of the sheet is not particularly limited, but is preferably 20 MPa or less. Here, the tensile elastic modulus of the sheet is a value measured according to JIS P 8113 except that the sheet length is 40 mm and the chuck distance is 20 mm. When measuring the tensile modulus, the basis weight of the sheet is measured under the same conditions. The basis weight of the sheet is not particularly limited, but the measurement is performed, for example, at 80 g/m ² . Further, the total content of the fibrous cellulose and the organic onium ion relative to the total mass of the sheet to be subjected to the measurement of the tensile elastic modulus is preferably 80% by mass or more, more preferably 85% by mass or more, It is more preferably 90% by mass or more. Here, the total content of the fibrous cellulose and the organic onium ion, the fibrous cellulose having a phosphorus oxo acid group, and the total mass of the organic onium ion present as a counter ion of the phosphorus oxo acid group, the fibrous cellulose containing It is a value calculated by dividing by the mass of the product. When measuring the tensile elastic modulus, the sheet is conditioned at 23° C. and 50% relative humidity for 24 hours and then measured. As the tensile tester used for the measurement, for example, a tensile tester Tensilon manufactured by A&D Co. can be used. The tensile modulus is a value calculated from the maximum positive slope value in the stress-strain curve (SS curve).

The content of the fibrous cellulose with respect to the total mass of the fibrous cellulose-containing material is preferably 10% by mass or more, more preferably 15% by mass or more, further preferably 20% by mass or more, and 25% by mass. % Or more is particularly preferable. The upper limit of the content of fibrous cellulose may be 99 mass% with respect to the total mass of the fibrous cellulose-containing material. The content of fibrous cellulose in the fibrous cellulose-containing material is a value calculated by dividing the mass of fibrous cellulose by the mass of the fibrous cellulose-containing material. However, the mass of the fibrous cellulose is the mass when it is assumed that the counter ion of the anionic group of the fibrous cellulose is hydrogen ion (H ⁺ ). Here, regarding the mass of the fibrous cellulose, the solid content remaining after the fibrous cellulose is extracted by an appropriate method and subjected to this operation becomes the mass of the fibrous cellulose. Examples of the extraction method include a method of selectively extracting, as a salt, a component present as a counter ion of the phosphorus oxo acid group of the fine fibrous cellulose by acid treatment.

In the fibrous cellulose-containing material of the present invention, it is preferable that the content of water is small. The content of water in the fibrous cellulose-containing material is preferably 20% by mass or less, more preferably 18% by mass or less, and 15% by mass or less with respect to the total mass of the fibrous cellulose-containing material. It is more preferable that the amount is 10% by mass or less. The content of water in the fibrous cellulose-containing material may be 0% by mass. As described above, since the fibrous cellulose-containing material of the present invention has a low water content, the amount of water brought into an organic solvent slurry obtained by dispersing fine fibrous cellulose in an organic solvent is suppressed. The water content in the fibrous cellulose-containing material can be measured by placing 200 mg of the fibrous cellulose-containing material on a water content meter (MS-70 manufactured by A&D Company) and heating at 140°C. it can. The water content in the fibrous cellulose-containing material can be calculated from the measured water content.

The fibrous cellulose-containing material of the present invention may be in solid or gel form. The fibrous cellulose-containing material of the present invention is preferably used for forming a molded product such as a sheet. That is, the fibrous cellulose-containing material of the present invention is preferably a molded body forming composition, and more preferably a sheet forming composition.

When the fibrous cellulose-containing material of the present invention is in a solid state, its form is not particularly limited, but for example, it is preferably a sheet-like material or a granular material, and more preferably a granular material. preferable. Here, the granular material is a powdery and/or granular substance. Note that the powdery substance means a substance smaller than the granular substance. Generally, 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 mm to 10 mm, but is not particularly limited. In addition, in this specification, a granular material may be called powder. The particle size of the powder or granular material in the present specification can be measured and calculated using a laser diffraction method. Specifically, it is a value measured using a laser diffraction/scattering particle size distribution measuring device (Microtrac 3300EXII, Nikkiso Co., Ltd.).

(Fibrous cellulose)
The fibrous cellulose-containing material of the present invention contains fibrous cellulose having a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid group. Here, the fiber width of the fibrous cellulose is 1000 nm or less. The fiber width of the fibrous cellulose is preferably 100 nm or less, more preferably 8 nm or less. Thereby, the dispersibility in the organic solvent can be enhanced more effectively. In the present specification, fibrous cellulose having a fiber width of 1000 nm or less may be referred to as fine fibrous cellulose.

The fiber width of the fibrous cellulose can be measured by, for example, observation with an electron microscope. The average fiber width of the fibrous cellulose is, for example, 1000 nm or less. The average fiber width of the fibrous cellulose is, for example, preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, further preferably 2 nm or more and 50 nm or less, and 2 nm or more and 10 nm or less. Particularly preferred. By setting the average fiber width of the fibrous cellulose to 2 nm or more, it is possible to prevent the fibrous cellulose from being dissolved in water and more easily exhibit the effect of improving the strength, rigidity, and dimensional stability of the fibrous cellulose. it can. The fibrous cellulose is, for example, monofilament cellulose.

The average fiber width of the fibrous cellulose is measured, for example, using an electron microscope as follows. First, an aqueous suspension of fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less is prepared, and the suspension is cast on a hydrophilized carbon film-coated grid to obtain a TEM observation sample. And When a wide fiber is included, an SEM image of the surface cast on glass may be observed. Then, observation with an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 times or 50000 times according to the width of the fiber to be observed. However, the sample, observation conditions and magnification are adjusted so as to satisfy the following conditions.
(1) One straight line X is drawn at an arbitrary position in the observed 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 intersecting the straight line X and the straight line Y is visually read from the observed image satisfying the above conditions. In this way, at least three sets of observation images of surface portions that do not overlap each other are obtained. Then, for each image, the width of the fiber intersecting the straight line X and the straight line Y is read. Thereby, the fiber width of at least 20 fibers×2×3=120 fibers is read. Then, the average value of the read fiber width is set as the average fiber width of the fibrous cellulose.

The fiber length of the fibrous cellulose is not particularly limited, but is preferably 0.1 μm or more and 1000 μm or less, more preferably 0.1 μm or more and 800 μm or less, and further preferably 0.1 μm or more and 600 μm or less. preferable. By setting the fiber length within the above range, breakage of the crystalline region of the fibrous cellulose can be suppressed. It is also possible to set the slurry viscosity of the fibrous cellulose within an appropriate range. The fiber length of the fibrous cellulose can be determined by image analysis using TEM, SEM, or AFM, for example.

The fibrous cellulose preferably has a type I crystal structure. Here, the fact that the fibrous cellulose has an I-type crystal structure can be identified in a diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ=1.5418Å) monochromated with graphite. Specifically, it can be identified by having typical peaks at two positions near 2θ=14° or more and 17° or less and around 2θ=22° or more and 23° or less. The proportion of the I-type crystal structure in the fine fibrous cellulose is, for example, preferably 30% or more, more preferably 40% or more, and further preferably 50% or more. Thereby, further excellent performance can be expected in terms of heat resistance and low linear thermal expansion coefficient. The crystallinity is obtained by measuring an X-ray diffraction profile and using the pattern according to a conventional method (Seagal et al., Textile Research Journal, Vol. 29, page 786, 1959).

The axial ratio (fiber length/fiber width) of the fibrous cellulose is not particularly limited, but is preferably 20 or more and 10000 or less, and more preferably 50 or more and 1000 or less. By setting the axial ratio to the above lower limit or more, it is easy to form a sheet containing fine fibrous cellulose. By setting the axial ratio to be equal to or less than the above upper limit, for example, when handling fibrous cellulose as a dispersion liquid, handling such as dilution becomes easy, which is preferable.

The fibrous cellulose in this embodiment has both a crystalline region and an amorphous region, for example. In particular, fine fibrous cellulose having both a crystalline region and an amorphous region and a high axial ratio is realized by the method for producing fine fibrous cellulose described below.

Fibrous cellulose has a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid group (sometimes referred to simply as a phosphorus oxo acid group). The substituent derived from the phosphorus oxo acid group includes a substituent such as a salt of the phosphorus oxo acid group and a phosphorus oxo acid ester group. Since the phosphorus oxo acid group is an anionic group, it can have an organic onium ion as a counter ion. It is considered that this can enhance the dispersibility of the fine fibrous cellulose in the organic solvent.

The introduction amount of phosphorus oxo acid group (the amount of phosphorus oxo acid group) in the fibrous cellulose is, for example, preferably 0.10 mmol/g or more per 1 g (mass) of the fibrous cellulose, and more preferably 0.20 mmol/g or more. It is more preferably 0.50 mmol/g or more, still more preferably 1.00 mmol/g or more. Further, the introduction amount of the phosphorus oxo acid group in the fibrous cellulose is, for example, preferably 5.20 mmol/g or less per 1 g (mass) of the fibrous cellulose, more preferably 3.65 mmol/g or less. More preferably, it is not more than 00 mmol/g. Here, the unit mmol/g indicates the amount of the substituent per 1 g of the mass of the fibrous cellulose when the counter ion of the phosphorus oxo acid group is a hydrogen ion (H ⁺ ). By setting the introduction amount of the phosphorus oxo acid group within the above range, it is possible to facilitate the miniaturization of the fiber raw material and increase the stability of the fibrous cellulose. Furthermore, by setting the introduction amount of the phosphorus oxo acid group in the above range, the content of the organic onium ion that can be contained in the fibrous cellulose can be set to an appropriate range, and thus the dispersion of the fibrous cellulose in the organic solvent can be performed. The sex can be enhanced more effectively. Further, when the amount of the phosphorus oxo acid group introduced is within the above range, the sheet can exhibit a high tensile elastic modulus when the sheet is formed from the redispersed slurry.

The amount of phosphorus oxo acid group introduced into the fibrous cellulose can be measured, for example, by the neutralization titration method. In the measurement by the neutralization titration method, the introduced amount is measured by determining the pH change while adding an alkali such as an aqueous sodium hydroxide solution to the obtained slurry containing fibrous cellulose.

FIG. 1 is a graph showing the relationship between the dropping amount of NaOH and pH for a slurry containing fibrous cellulose having a phosphorous acid group. The amount of phosphorus oxo acid group introduced into the fibrous cellulose is measured, for example, as follows.
First, a slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, a defibration process similar to the defibration process step described below may be performed on the measurement target before the treatment with the strongly acidic ion exchange resin.
Then, the pH change is observed while adding the aqueous sodium hydroxide solution, and a titration curve as shown in the upper part of FIG. 1 is obtained. In the titration curve shown in the upper part of FIG. 1, the measured pH is plotted against the amount of alkali added, and in the titration curve shown in the lower part of FIG. 1, the pH is plotted against the amount of alkali added. The increment (differential value) (1/mmol) is plotted. In this neutralization titration, two points at which the increment (the differential value of pH with respect to the amount of alkali added) is maximized are confirmed in the curve plotting the pH measured with respect to the amount of alkali added. Among these, the maximum point of the increment obtained first after adding alkali is referred to as a first end point, and the maximum point of the increment obtained next is referred to as a second end point. The amount of alkali required from the start of titration to the first end point becomes equal to the amount of the first dissociated acid of fibrous cellulose contained in the slurry used for the titration, and the alkali amount required from the first end point to the second end point. The amount becomes equal to the amount of the second dissociated acid of the fibrous cellulose contained in the slurry used for the titration, and the amount of alkali required from the start of the titration to the second end point becomes the total amount of the dissociated acid in the slurry used for the titration. Will be equal. The value obtained by dividing the amount of alkali required from the start of titration to the first end point by the solid content (g) in the slurry to be titrated is the phosphorus oxo acid group introduction amount (mmol/g). In addition, when simply saying the phosphorus oxo acid group introduction amount (or phosphorus oxo acid group amount), it means the first dissociation acid amount.
In FIG. 1, the region from the start of titration to the first end point is called the first region, and the region from the first end point to the second end point is called the second region. For example, when the phosphorous acid group is a phosphoric acid group and the phosphoric acid group causes condensation, the amount of the weakly acidic group in the phosphorous acid group (also referred to as the amount of the second dissociated acid in the present specification) is apparent. As a result, the amount of alkali required for the second region decreases compared to the amount of alkali required for the first region. On the other hand, the amount of the strongly acidic group in the phosphorus oxo acid group (also referred to as the amount of the first dissociated acid in the present specification) matches the amount of the phosphorus atom regardless of the presence or absence of condensation. Further, when the phosphorous acid group is a phosphorous acid group, since the weakly acidic group does not exist in the phosphorous acid group, the alkali amount required for the second region is reduced or the alkali amount required for the second region is reduced. May be zero. In this case, there is only one point in the titration curve where the pH increment becomes maximum.

In the measurement of the amount of phosphorus oxo acid group by the titration method, if the amount of sodium hydroxide aqueous solution is too large, the amount of phosphorus oxo acid group may be lower than it should be. It is desirable to titrate 10 to 50 μL of the aqueous sodium hydroxide solution every 5 to 30 seconds. In order to eliminate the influence of carbon dioxide dissolved in the fibrous cellulose-containing slurry, for example, it is desirable to perform titration while blowing an inert gas such as nitrogen gas into the slurry 15 minutes before the start of titration.

In the first aspect of the present invention, when the first dissociated acid amount (mmol/g) in the fibrous cellulose is A1 and the total dissociated acid amount (mmol/g) in the fibrous cellulose is A2, A1/A2 The value may be 0.65 or more, preferably 0.68 or more, more preferably 0.70 or more, and further preferably 0.80 or more. Further, the upper limit value of A1/A2 is preferably 1.0. Here, the first dissociated acid amount (A1) in the fibrous cellulose is the amount of alkali (mmol) required from the start of titration to the first end point in the titration curve described above, and the solid content (g ) Divided by. That is, the first dissociated acid amount (A1) is a value obtained by dividing the substance amount (mmol) of the acid ionized and neutralized in the first step by the solid content (g) in the titration target slurry. The total amount of dissociated acid (A2) in the fibrous cellulose is a value obtained by dividing the amount of alkali (mmol) required from the start of titration to the second end point by the solid content (g) in the titration target slurry. That is, the total dissociated acid amount (A2) is a value obtained by dividing the substance amount (mmol) of all the acids that are ionized in all stages and neutralized by the solid content (g) in the titration target slurry. Therefore, as the value of A1/A2 is closer to 1, it means that the amount of weak acid (such as the amount of weakly acidic group in phosphorous acid group) is smaller. In the first aspect of the present invention, by setting the value of A1/A2 within the above range, the dispersibility of the fibrous cellulose-containing material in an organic solvent is increased, and at the same time, an organic onium ion is used as a counter ion. Even if it exists, the tensile elastic modulus of the obtained sheet can be increased.

The value of A1/A2 approaches 1 in both cases where the phosphoric acid group is condensed and when the phosphorous acid group is present. As a method for determining whether the factor that A1/A2 approaches 1 is due to the condensation of a phosphoric acid group or the presence of a phosphorous acid group, for example, a condensed structure of phosphoric acid such as acid hydrolysis is used. Examples include a method of performing the above-mentioned titration operation after the treatment of cutting, a method of performing the above-mentioned titration operation after performing a treatment of converting a phosphite group into a phosphate group such as an oxidation treatment.

The phosphorus oxo acid group or the substituent derived from the phosphorus oxo acid group is, for example, a substituent represented by the following formula (1). The substituent derived from the phosphorus oxo acid group includes a substituent such as a salt of the phosphorus oxo acid group and a phosphorus oxo acid ester group. Further, the substituent derived from the phosphorus oxo acid group may be contained in the fibrous cellulose as a group condensed with the phosphorus oxo acid group (for example, a pyrophosphate group).

In the formula (1), a, b and n are natural numbers and m is an arbitrary number (provided that a=b×m). Of α ¹ , α ² ,..., α ⁿ and α′, a is O ⁻ , and the rest is either R or OR. Here, R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched hydrocarbon group. It is a hydrocarbon group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or a derivative group thereof. R may be a group derived from a cellulose molecular chain. Of these, either α ⁿ or α′ is preferably R, and R is particularly preferably a hydrogen atom. Further, n is preferably 1. That is, the phosphorus oxo acid group or the substituent derived from the phosphorus oxo acid group is preferably a phosphorous acid group or a substituent derived from the phosphorous acid group.

In the second aspect of the present invention, the fibrous cellulose has a phosphorous acid group or a substituent derived from a phosphorous acid group. That is, in the formula (1), a of α ⁿ and α′ is O ⁻ , and either α ⁿ or α′ is R. Above all, R is preferably a hydrogen atom.

Note that a part of the phosphorus oxo acid group or the substituent derived from the phosphorus oxo acid group may be a phosphoric acid group or a substituent derived from the phosphoric acid group, or a group in which the phosphorus oxo acid group is condensed (for example, pyrophosphoric acid Group). Thus, the fibrous cellulose is a phosphorous acid group or a substituent group derived from a phosphorous acid group (hereinafter, also simply referred to as a phosphorous acid group), and a substituent group derived from a phosphoric acid group or a phosphoric acid group (hereinafter , Also referred to simply as a phosphoric acid group) as a substituent, the proportion of the phosphorous acid group in the substituent represented by the formula (1) is preferably 30% by mass or more, and 40% by mass. % Or more, and more preferably 50% by mass or more.

Examples of the saturated-linear hydrocarbon group represented by R in the formula (1) include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, but are not particularly limited. Examples of the saturated-branched hydrocarbon group include i-propyl group and t-butyl group, but are not particularly limited. Examples of the saturated-cyclic hydrocarbon group include a cyclopentyl group and a cyclohexyl group, but are not particularly limited. Examples of the unsaturated-straight chain hydrocarbon group include a vinyl group and an allyl group, but are not particularly limited. Examples of the unsaturated-branched hydrocarbon group include, but are not limited to, i-propenyl group and 3-butenyl group. Examples of the unsaturated-cyclic hydrocarbon group include, but are not limited to, a cyclopentenyl group and a cyclohexenyl group. Examples of the aromatic group include a phenyl group and a naphthyl group, but are not particularly limited.

Further, the derivative group in R is a functional group in which at least one of functional groups such as a carboxy group, a hydroxy group, or an amino group is added or substituted to the main chain or side chain of the above-mentioned various hydrocarbon groups. Examples thereof include groups, but are not particularly limited. Further, the number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R in the above range, the molecular weight of the phosphorus oxo acid group can be set in an appropriate range, the permeation into the fiber raw material is facilitated, and the yield of fine cellulose fibers is increased. You can also

β ^b+ is a monovalent or higher cation composed of an organic substance or an inorganic substance. Examples of monovalent or higher cations composed of organic substances include aliphatic ammonium and aromatic ammonium, and at least a part of β ^b+ is an organic onium ion described later. Examples of the monovalent or more cations made of an inorganic material include alkali metal ions such as sodium, potassium, or lithium, divalent metal cations such as calcium or magnesium, or hydrogen ions. It is not particularly limited. These may be applied alone or in combination of two or more. As the cation having a valence of 1 or more consisting of an organic substance or an inorganic substance, sodium or potassium ions, which are less likely to yellow when the β-containing fiber raw material is heated and are industrially usable, are preferred, but are not particularly limited.

The fact that the fibrous cellulose has a phosphite group as a substituent means that the infrared absorption spectrum of the dispersion containing the fibrous cellulose was measured, and phosphon, which is a tautomer of the phosphite group, was found around 1210 cm ^-1. This can be confirmed by observing absorption based on P=O of the acid group. Further, the fibrous cellulose having a phosphite group as a substituent includes a method of confirming a chemical shift using NMR, and a method of combining various titration methods with elemental analysis.

The fibrous cellulose may have another anionic group in addition to the phosphorus oxo acid group or the substituent derived from the phosphorus oxo acid group. Examples of such an anionic group include a carboxy group originally contained in pulp.

<Production process of fine fibrous cellulose>
<Fiber raw material>
Fine fibrous cellulose is manufactured from a fiber raw material containing cellulose. The fiber raw material containing cellulose is not particularly limited, but pulp is preferably used because it is easily available and inexpensive. Pulps include, for example, wood pulp, non-wood pulp, and deinked pulp. The wood pulp is not particularly limited, and examples thereof include hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP). ) And chemical pulp such as oxygen bleached kraft pulp (OKP), semi-chemical pulp such as semi-chemical pulp (SCP) and chemiground wood pulp (CGP), groundwood pulp (GP) and thermomechanical pulp (TMP, BCTMP) etc. Examples include mechanical pulp. The non-wood pulp is not particularly limited, but examples thereof include cotton-based pulp such as cotton linter and cotton lint, and non-wood-based pulp such as hemp, straw and bagasse. The deinked pulp is not particularly limited, and examples thereof include deinked pulp made from waste paper. The pulp of this embodiment may be used alone or as a mixture of two or more kinds. Among the above pulps, for example, wood pulp and deinked pulp are preferable from the viewpoint of easy availability. Further, among wood pulp, a viewpoint of a high yield of fine fibrous cellulose at the time of defibration treatment with a large cellulose ratio and a long fiber fine fibrous cellulose with a small decomposition of cellulose in the pulp and a large axial ratio can be obtained. From the viewpoint, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are further preferable. The viscosity tends to increase when fine fibrous cellulose of long fibers having a large axial ratio is used.

As the fiber raw material containing cellulose, for example, cellulose contained in ascidians or bacterial cellulose produced by acetic acid bacteria can be used. Further, instead of the fiber raw material containing cellulose, a fiber formed by a linear nitrogen-containing polysaccharide polymer such as chitin or chitosan may be used.

<Phosphorus oxo acid group introduction step>
The manufacturing process of fine fibrous cellulose includes a phosphoroxo acid group introduction process. In the phosphorus oxo acid group introducing step, at least one compound selected from compounds capable of introducing a phosphorus oxo acid group by reacting with a hydroxyl group of a fiber raw material containing cellulose (hereinafter, also referred to as “compound A”) Is a step of acting on a fiber raw material containing. By this step, a phosphorous acid group-introduced fiber can be obtained.

In the phosphorus oxo acid group introduction step according to the present embodiment, the reaction of the cellulose-containing fiber raw material and the compound A is performed in the presence of at least one selected from urea and its derivatives (hereinafter, also referred to as “compound B”). May be. On the other hand, the reaction of the fiber raw material containing cellulose with the compound A may be carried out in the state where the compound B does not exist.

As an example of a method of allowing the compound A to act on the fiber raw material in the coexistence with the compound B, a method of mixing the compound A and the compound B with the fiber raw material in a dry state, a wet state or a slurry state can be mentioned. Among these, it is preferable to use a fiber raw material in a dry state or a wet state, and particularly preferable to use a fiber raw material in a dry state, since the reaction is highly uniform. The form of the fiber raw material is not particularly limited, but is preferably cotton-like or thin sheet-like, for example. Compound A and compound B may be added to the fiber raw material in the form of powder or solution dissolved in a solvent, or heated to a melting point or higher and melted. Among these, since the reaction is highly uniform, it is preferable to add them in the form of a solution dissolved in a solvent, particularly in the state of an aqueous solution. Further, the compound A and the compound B may be added to the fiber raw material at the same time, may be added separately, or may be added as a mixture. The method of adding the compound A and the compound B is not particularly limited, but when the compound A and the compound B are in the form of a solution, the fiber raw material may be dipped in the solution to absorb the liquid, and then taken out. The solution may be added dropwise. Further, the required amounts of compound A and compound B may be added to the fiber raw material, or excess amounts of compound A and compound B may be respectively added to the fiber raw material, and then excess compound A and compound B may be squeezed or filtered. May be removed.

Examples of the compound A used in this embodiment include compounds having a phosphorus atom and capable of forming an ester bond with cellulose. The compound A contains at least a compound having a phosphorous acid group and/or a salt thereof. .. Examples of the compound having a phosphorous acid group include phosphorous acid, and examples of the phosphorous acid include 99% phosphorous acid (phosphonic acid). Examples of the salt of phosphorous acid include lithium salt, sodium salt, potassium salt, and ammonium salt of phosphorous acid, which can have various degrees of neutralization. Among these, from the viewpoint of high efficiency of introduction of phosphorus oxo acid group, easier improvement of defibration efficiency in the defibration step described later, low cost, and easy industrial application, phosphorous acid, phosphorus phosphite The sodium salt of an acid, the potassium salt of phosphorous acid, or the ammonium salt of phosphorous acid is preferable, and phosphorous acid is more preferable. In addition to the compound having a phosphorous acid group and/or a salt thereof, the compound A is a compound having a phosphoric acid group and/or a salt thereof, dehydrated condensed phosphoric acid and/or a salt thereof, and phosphoric anhydride (pentoxide). Diphosphorus) and the like. In this case, phosphoric acid having various purities can be used, and for example, 100% phosphoric acid (orthophosphoric acid) or 85% phosphoric acid can be used. The dehydrated condensed phosphoric acid is one in which two or more molecules of phosphoric acid are condensed by a dehydration reaction, and examples thereof include pyrophosphoric acid and polyphosphoric acid.

The addition amount of the compound A to the fiber raw material is not particularly limited, but when the addition amount of the compound A is converted into the phosphorus atomic weight, the addition amount of the phosphorus atom to the fiber raw material (absolute dry mass) is 0.5% by mass or more. It is preferably 100% by mass or less, more preferably 1% by mass or more and 50% by mass or less, still more preferably 2% by mass or more and 30% by mass or less. By setting the amount of phosphorus atoms added to the fiber raw material within the above range, the yield of fine fibrous cellulose can be further improved. On the other hand, by controlling the amount of phosphorus atoms added to the fiber raw material to be not more than the above upper limit, the effect of improving the yield and the cost can be balanced.

The compound B used in this embodiment is at least one selected from urea and its derivatives as described above. Examples of the compound B include urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like.
From the viewpoint of improving the uniformity of the reaction, the compound B is preferably used as an aqueous solution. From the viewpoint of further improving the homogeneity of the reaction, it is preferable to use an aqueous solution in which both compound A and compound B are dissolved.

The amount of the compound B added to the fiber raw material (absolute dry mass) is not particularly limited, but is preferably 1% by mass or more and 500% by mass or less, more preferably 10% by mass or more and 400% by mass or less, More preferably, it is 100% by mass or more and 350% by mass or less.

In the reaction between the fiber raw material containing cellulose and the compound A, in addition to the compound B, for example, amides or amines may be included in the reaction system. Examples of the amides include formamide, dimethylformamide, acetamide, dimethylacetamide and the like. Examples of amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, and hexamethylenediamine. Of these, triethylamine is known to work particularly as a good reaction catalyst.

In the phosphorus oxo acid group-introducing step, it is preferable to heat or heat the fiber raw material after adding or mixing the compound A or the like to the fiber raw material. As the heat treatment temperature, it is preferable to select a temperature at which the phosphorus oxo acid group can be efficiently introduced while suppressing thermal decomposition and hydrolysis reaction of the fiber. The heat treatment temperature is, for example, preferably 50° C. or higher and 300° C. or lower, more preferably 100° C. or higher and 250° C. or lower, and further preferably 130° C. or higher and 200° C. or lower. Further, for the heat treatment, equipment having various heat mediums can be used, for example, a stirring dryer, a rotary dryer, a disc dryer, a roll heater, a plate heater, a fluidized bed dryer, and an air flow. A drying device, a reduced pressure drying device, an infrared heating device, a far infrared heating device, a microwave heating device, and a high frequency drying device can be used.

In the heat treatment according to the present embodiment, for example, a method of adding compound A to a thin sheet-shaped fiber raw material by a method such as impregnation and then heating, or heating while kneading or stirring the fiber raw material and compound A with a kneader or the like. Can be adopted. This makes it possible to suppress unevenness in the concentration of the compound A in the fiber raw material and more uniformly introduce the phosphorus oxo acid group to the surface of the cellulose fiber contained in the fiber raw material. This is because when water molecules move to the surface of the fiber raw material due to drying, the dissolved compound A is attracted to the water molecules by the surface tension and similarly moves to the surface of the fiber raw material (that is, uneven concentration of compound A It is thought to be due to the fact that it can be suppressed.

In addition, the heating device used for the heat treatment always keeps, for example, the water retained by the slurry and the water generated by the dehydration condensation (phosphoric acid esterification) reaction between the compound A and the hydroxyl groups contained in the cellulose or the like in the fiber raw material. It is preferable that the device can be discharged to the outside of the device system. An example of such a heating device is a blower type oven. By constantly discharging the water in the device system, in addition to suppressing the hydrolysis reaction of the phosphoric acid ester bond, which is the reverse reaction of phosphoric acid esterification, it is also possible to suppress the acid hydrolysis of sugar chains in the fiber. it can. Therefore, it becomes possible to obtain fine fibrous cellulose having a high axial ratio.

The heat treatment time is, for example, preferably 1 second or more and 300 minutes or less, more preferably 1 second or more and 1000 seconds or less, and more preferably 10 seconds or more and 800 seconds or less after water is substantially removed from the fiber raw material. Is more preferable. In the present embodiment, the introduction amount of the phosphorus oxo acid group can be set within the preferable range by setting the heating temperature and the heating time within appropriate ranges.

The phosphorus oxo acid group introduction step may be performed at least once, but may be repeated twice or more. By performing the phosphorus oxo acid group introduction step twice or more, many phosphorus oxo acid groups can be introduced into the fiber raw material. In the present embodiment, as an example of a preferable mode, a case where the phosphorus oxo acid group introduction step is performed twice is mentioned.

<Washing process>
In the method for producing fine fibrous cellulose according to the present embodiment, a washing step can be performed on the phosphorus oxo acid group-introduced fiber, if necessary. The washing step is performed, for example, by washing the phosphorus oxo acid group-introduced fiber with water or an organic solvent. The cleaning step may be performed after each step described below, and the number of times of cleaning performed in each cleaning step is not particularly limited.

<Alkali treatment process>
In the case of producing fine fibrous cellulose, alkali treatment may be performed on the phosphorus oxo acid group-introduced fiber between the phosphorus oxo acid group introduction step and the defibration treatment step described later. The method of alkali treatment is not particularly limited, and examples thereof include a method of immersing the phosphorous acid group-introduced fiber in an alkali solution.

The alkaline compound contained in the alkaline solution is not particularly limited, and may be an inorganic alkaline compound or an organic alkaline compound. In this embodiment, for example, sodium hydroxide or potassium hydroxide is preferably used as the alkali compound because of its high versatility. Further, the solvent contained in the alkaline solution may be either water or an organic solvent. Among them, the solvent contained in the alkaline solution is preferably a polar solvent containing water or a polar organic solvent exemplified by alcohol, and more preferably an aqueous solvent containing at least water. As the alkaline solution, for example, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is preferable because of its high versatility.

The temperature of the alkaline solution in the alkaline treatment step is not particularly limited, but is preferably 5° C. or higher and 80° C. or lower, and more preferably 10° C. or higher and 60° C. or lower. The time for immersing the phosphorus oxo acid group-introduced fiber in the alkaline solution in the alkaline treatment step is not particularly limited, but is preferably 5 minutes or more and 30 minutes or less, and more preferably 10 minutes or more and 20 minutes or less. The amount of the alkaline solution used in the alkaline treatment is not particularly limited, but for example, it is preferably 100% by mass or more and 100000% by mass or less, and 1000% by mass or more and 10000% by mass or less based on the absolutely dry mass of the phosphorus oxo acid group-introduced fiber. Is more preferable.

In order to reduce the amount of the alkaline solution used in the alkali treatment step, the phosphorus oxo acid group-introduced fiber may be washed with water or an organic solvent after the phosphorus oxo acid group introduction step and before the alkali treatment step. After the alkali treatment step and before the defibration treatment step, it is preferable to wash the alkali-treated phosphorus oxo acid group-introduced fiber with water or an organic solvent from the viewpoint of improving handleability.

<Acid treatment step>
In the case of producing fine fibrous cellulose, an acid treatment may be performed on the phosphorus oxo acid group-introduced fiber between the step of introducing the phosphorus oxo acid group and the defibration treatment step described later. For example, the phosphorus oxo acid group introduction step, the acid treatment, the alkali treatment and the defibration treatment may be performed in this order.

The method of acid treatment is not particularly limited, and examples thereof include a method of immersing the fiber raw material in an acid solution containing an acid. The concentration of the acidic liquid used is not particularly limited, but is, for example, preferably 10% by mass or less, and more preferably 5% by mass or less. The pH of the acidic liquid used is not particularly limited, but is, for example, preferably 0 or more and 4 or less, and more preferably 1 or more and 3 or less. As the acid contained in the acidic liquid, for example, an inorganic acid, a sulfonic acid, a carboxylic acid or the like can be used. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, phosphoric acid, boric acid and the like. Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and the like. Examples of the carboxylic acid include formic acid, acetic acid, citric acid, gluconic acid, lactic acid, oxalic acid, tartaric acid and the like. Among these, it is particularly preferable to use hydrochloric acid or sulfuric acid.

The temperature of the acid solution in the acid treatment is not particularly limited, but is preferably 5°C or higher and 100°C or lower, more preferably 20°C or higher and 90°C or lower. The immersion time in the acid solution in the acid treatment is not particularly limited, but is preferably 5 minutes or more and 120 minutes or less, more preferably 10 minutes or more and 60 minutes or less. The amount of the acid solution used in the acid treatment is not particularly limited, but is preferably 100% by mass or more and 100000% by mass or less, and 1000% by mass or more and 10000% by mass or less, with respect to the absolutely dry mass of the phosphorus oxo acid group-introduced fiber. Is more preferable.

<Disentanglement treatment>
Finely fibrous cellulose can be obtained by defibrating the phosphorus oxo acid group-introduced fiber in the defibrating step. In the defibration processing step, for example, a defibration processing device can be used. The defibration treatment device is not particularly limited, but includes, for example, a high-speed defibration device, a grinder (stone mill type crusher), a high pressure homogenizer or an ultrahigh pressure homogenizer, a high pressure collision type crusher, a ball mill, a bead mill, a disc type refiner, a conical refiner, a twin screw A kneader, a vibration mill, a homomixer under high speed rotation, an ultrasonic disperser, a beater, or the like can be used. Among the above-mentioned defibration treatment devices, it is more preferable to use a high-speed defibration machine, a high-pressure homogenizer, and an ultrahigh-pressure homogenizer that are less affected by the grinding media and less likely to cause contamination.

In the defibration treatment step, for example, it is preferable that the phosphorus oxo acid group-introduced fiber is diluted with a dispersion medium to form a slurry. As the dispersion medium, water and one or more selected from organic solvents such as polar organic solvents can be used. The polar organic solvent is not particularly limited, but alcohols, polyhydric alcohols, ketones, ethers, esters, aprotic polar solvents and the like are preferable. Examples of alcohols include methanol, ethanol, isopropanol, n-butanol, and isobutyl alcohol. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin and the like. Examples of the ketones include acetone and methyl ethyl ketone (MEK). Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and propylene glycol monomethyl ether. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the aprotic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP) and the like.

The solid content concentration of the fine fibrous cellulose during the defibration treatment can be set appropriately. Further, the slurry obtained by dispersing the phosphorus oxo acid group-introduced fiber in the dispersion medium may contain solid components other than the phosphorus oxo acid group introduced fiber such as urea having hydrogen bonding property.

(Organic onium ion)
The fibrous cellulose-containing material of the present invention contains an organic onium ion as a counter ion of the phosphorus oxo acid or the substituent derived from the phosphorus oxo acid contained in the fibrous cellulose. In the present invention, at least a part of the organic onium ion is present as a counter ion of the fibrous cellulose, but a free organic onium ion may be present in the fibrous cellulose-containing material. The organic onium ion does not form a covalent bond with fibrous cellulose.

The organic onium ion preferably satisfies at least one condition selected from the following (a) and (b).
(A) It contains a hydrocarbon group having 5 or more carbon atoms.
(B) The total carbon number is 17 or more.
That is, the fibrous cellulose contains at least one selected from an organic onium ion containing a hydrocarbon group having 5 or more carbon atoms and an organic onium ion having 17 or more carbon atoms as a counter ion of a phosphorus oxo acid group. Is preferred. When the organic onium ion satisfies at least one condition selected from the above (a) and (b), the dispersibility of the fibrous cellulose in the organic solvent can be more effectively enhanced.

The hydrocarbon group having 5 or more carbon atoms is preferably an alkyl group having 5 or more carbon atoms or an alkylene group having 5 or more carbon atoms, and an alkyl group having 6 or more carbon atoms or an alkylene having 6 or more carbon atoms. More preferably, it is an alkyl group having a carbon number of 7 or more, or an alkylene group having a carbon number of 7 or more, and an alkyl group having a carbon number of 10 or more or an alkylene group having a carbon number of 10 or more. It is particularly preferable that Among them, the organic onium ion is preferably one having an alkyl group having 5 or more carbon atoms, more preferably an organic onium ion containing an alkyl group having 5 or more carbon atoms and having a total carbon number of 17 or more. preferable.

The organic onium ion is preferably an organic onium ion represented by the following general formula (A).

In the above general formula (A), M is a nitrogen atom or a phosphorus atom, and R _{1 to} R ₄ each independently represent a hydrogen atom or an organic group. However, at least one of R _{1 to} R ₄ is preferably an organic group having 5 or more carbon atoms, or the total number of carbon atoms of R _{1 to} R ₄ is preferably 17 or more.
Among them, M is preferably a nitrogen atom. That is, the organic onium ion is preferably an organic ammonium ion. At least one of R _{1 to} R ₄ is preferably an alkyl group having 5 or more carbon atoms, and the total number of carbon atoms of R _{1 to} R ₄ is 17 or more.

Examples of such organic onium ions include lauryl trimethyl ammonium, cetyl trimethyl ammonium, stearyl trimethyl ammonium, octyl dimethyl ethyl ammonium, lauryl dimethyl ethyl ammonium, didecyl dimethyl ammonium, lauryl dimethyl benzyl ammonium, tributyl benzyl ammonium, and methyl tri-n. -Octyl ammonium, hexyl ammonium, n-octyl ammonium, dodecyl ammonium, tetradecyl ammonium, hexadecyl ammonium, stearyl ammonium, N,N-dimethyl dodecyl ammonium, N,N-dimethyl tetradecyl ammonium, N,N-dimethyl hexadecyl Ammonium, N,N-dimethyl-n-octadecyl ammonium, dihexyl ammonium, di(2-ethylhexyl) ammonium, di-n-octyl ammonium, didecyl ammonium, didodecyl ammonium, didecyl methyl ammonium, N,N-didodecyl methyl Ammonium, polyoxyethylene dodecyl ammonium, alkyldimethylbenzylammonium, di-n-alkyldimethylammonium, behenyltrimethylammonium, tetraphenylphosphonium, tetraoctylphosphonium, acetonyltriphenylphosphonium, allyltriphenylphosphonium, amyltriphenylphosphonium, benzyl Examples thereof include triphenylphosphonium, ethyltriphenylphosphonium, diphenylpropylphosphonium, triphenylphosphonium, tricyclohexylphosphonium and tri-n-octylphosphonium. The alkyl group in alkyldimethylbenzylammonium and di-n-alkyldimethylammonium includes a linear alkyl group having 8 to 18 carbon atoms.

As shown in the general formula (A), the central element of the organic onium ion is bonded to a total of four groups or hydrogen. In the above-mentioned name of organic onium ion, when the number of bonded groups is less than 4, hydrogen atoms are bonded to the rest to form an organic onium ion. For example, in the case of N,N-didodecylmethylammonium, it can be judged from the name that two dodecyl groups and one methyl group are bonded. In this case, hydrogen is bonded to the remaining one to form an organic onium ion.

When the organic onium contains O atoms, the larger the mass ratio of C atoms to O atoms (C/O ratio), the more preferable. For example, C/O>5 is preferable. By increasing the C/O ratio to more than 5, a fibrous cellulose concentrate can be easily obtained when an organic onium ion or a compound that forms an organic onium ion by neutralization is added to a fibrous cellulose-containing slurry. Become.

The molecular weight of the organic onium ion is preferably 2000 or less, more preferably 1800 or less. By setting the molecular weight of the organic onium ion within the above range, the handling property of the fibrous cellulose can be improved. Further, by setting the molecular weight of the organic onium ion within the above range, it is possible to prevent the content rate of the fibrous cellulose in the fibrous cellulose-containing material from decreasing.

The content of the organic onium ion is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and 2.0% by mass or more based on the total mass of the fibrous cellulose-containing material. Is more preferable. The content of the organic onium ion is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total mass of the fibrous cellulose-containing material.

The content of the organic onium ion in the fibrous cellulose-containing material is preferably an equimolar amount to 2 times the molar amount of the phosphorus oxo acid group amount contained in the fibrous cellulose, but is not particularly limited. The content of the organic onium ion can be measured by tracing the atoms typically contained in the organic onium ion. Specifically, the amount of nitrogen atom is measured when the organic onium ion is an ammonium ion, and the amount of phosphorus atom is measured when the organic onium ion is a phosphonium ion. When the fibrous cellulose contains a nitrogen atom or a phosphorus atom in addition to the organic onium ion, a method of extracting only the organic onium ion, for example, after performing an extraction operation with an acid, the amount of the target atom is measured. do it.

The content of the organic onium ion in the fibrous cellulose-containing material is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and further preferably 2.0% by mass or more. .. The organic onium ion content is preferably 90% by mass or less, more preferably 80% by mass or less.
The organic onium content is the mass of the organic onium ion contained in the fibrous cellulose-containing material divided by the absolute dry mass of the fibrous cellulose-containing material. That is, the organic onium content rate is calculated using the following calculation formula.
Organic onium content (mass %)=100×A×M/(B×M+A×(M−m))
A: Mass (g) of organic onium ions generated from the organic onium tested at the time of production
B: Absolute dry mass (g) of fibrous cellulose contained in the fibrous cellulose dispersion liquid tested at the time of production
M: molecular weight of organic onium ion m: average of molecular weight (formula weight) of counterion of phosphorus oxo acid group in fibrous cellulose tested at the time of production

As described above, the organic onium ion is preferably an ion that exhibits hydrophobicity. That is, the fibrous cellulose in the present invention exhibits hydrophobicity by having an organic onium ion. Thereby, the redispersibility of the fibrous cellulose-containing material in the organic solvent can be more effectively enhanced, and the obtained redispersion slurry has a high viscosity.

(Arbitrary ingredient)
The fibrous cellulose-containing material of the present invention may further contain optional components. Examples of the optional component include a defoaming agent, a lubricant, an ultraviolet absorber, a dye, a pigment, a stabilizer, a surfactant, and a preservative. Further, the fibrous cellulose-containing material may contain a hydrophilic polymer, a hydrophilic low molecule, an organic ion, or the like as an optional component.

The hydrophilic polymer is preferably a hydrophilic oxygen-containing organic compound (excluding the above-mentioned cellulose fiber). Examples of the oxygen-containing organic compound include polyethylene glycol, polyethylene oxide, casein, dextrin, starch, and modified Starch, polyvinyl alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol, etc.), polyvinylpyrrolidone, polyvinyl methyl ether, polyacrylates, alkyl acrylate copolymers, urethane copolymers, cellulose derivatives (hydroxyethyl cellulose, carboxy) Ethyl cellulose, carboxymethyl cellulose, etc.) and the like.

The hydrophilic low-molecular weight compound is preferably a hydrophilic oxygen-containing organic compound, more preferably a polyhydric alcohol. Examples of the polyhydric alcohol include glycerin, sorbitol, ethylene glycol and the like.

Examples of organic ions include tetraalkylammonium ions and tetraalkylphosphonium ions. Examples of the tetraalkylammonium ion include tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrahexylammonium ion, tetraheptylammonium ion, tributylmethylammonium ion, and lauryltrimethyl. Examples thereof include ammonium ion, cetyl trimethyl ammonium ion, stearyl trimethyl ammonium ion, octyl dimethyl ethyl ammonium ion, lauryl dimethyl ethyl ammonium ion, didecyl dimethyl ammonium ion, lauryl dimethyl benzyl ammonium ion, and tributyl benzyl ammonium ion. Examples of the tetraalkylphosphonium ion include tetramethylphosphonium ion, tetraethylphosphonium ion, tetrapropylphosphonium ion, tetrabutylphosphonium ion, and lauryltrimethylphosphonium ion. Moreover, as tetrapropyl onium ion and tetrabutyl onium ion, tetra n-propyl onium ion, tetra n-butyl onium ion, etc. can be mentioned, respectively.

Moreover, a hygroscopic agent can also be mentioned as an arbitrary component. Examples of the hygroscopic agent include silica gel, zeolite, alumina, sepiolite, calcium oxide, diatomaceous earth, activated carbon, activated clay, white carbon, calcium chloride, magnesium chloride, potassium acetate, dibasic sodium phosphate, sodium citrate and the like. To be

(Method for producing fibrous cellulose-containing material)
The step of producing a fibrous cellulose-containing product includes a step of adding an organic onium ion or a compound that forms an organic onium ion by neutralization to a fine fibrous cellulose-containing slurry. Specifically, the above-mentioned organic onium ion or a compound that forms an organic onium ion by neutralization is added to the fine fibrous cellulose-containing slurry obtained in the above defibration treatment step. At this time, the organic onium ion is preferably added as a solution containing the organic onium ion, and more preferably as an aqueous solution containing the organic onium ion.

The aqueous solution containing an organic onium ion usually contains an organic onium ion and a counter ion (anion). When an aqueous solution of an organic onium ion is prepared, if the organic onium ion and the corresponding counter ion have already formed a salt, they may be dissolved in water as they are. When preparing an aqueous solution of an organic onium ion, when the organic onium ion and the corresponding counter ion have already formed a salt, it is preferably dissolved in water or hot water.

In addition, the organic onium ion may be produced only after being neutralized with an acid, such as dodecylamine. In this case, the organic onium ion is obtained by reacting a compound that forms an organic onium ion by neutralization with an acid. In this case, examples of the acid used for neutralization include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as lactic acid, acetic acid, formic acid and oxalic acid.

The step of adding an organic onium ion or a compound that forms an organic onium ion by neutralization to the fine fibrous cellulose-containing slurry preferably further includes a stirring step. This allows the counterion exchange in the fine fibrous cellulose to proceed sufficiently.

The addition amount of the organic onium ion is preferably 2% by mass or more, more preferably 10% by mass or more, and further preferably 50% by mass or more, based on the total mass of the fine fibrous cellulose. It is particularly preferably 100% by mass or more. The addition amount of the organic onium ion is preferably 1000% by mass or less based on the total mass of the fine fibrous cellulose.
Further, the number of moles of the organic onium ion to be added is preferably 0.2 times or more the value obtained by multiplying the amount (the number of moles) of the phosphorus oxo acid group contained in the fine fibrous cellulose by the valence, and is 0.5 times. More preferably, it is more preferably 1.0 times or more. The number of moles of the organic onium ion to be added is preferably 10 times or less the value obtained by multiplying the valence by the amount (number of moles) of the phosphorus oxo acid group contained in the fine fibrous cellulose.

When organic onium ions are added and stirred, aggregates are generated in the slurry containing fine fibrous cellulose. This aggregate is an aggregate of fine fibrous cellulose having an organic onium ion as a counter ion. The fine fibrous cellulose agglomerates can be collected by filtering the slurry containing fine fibrous cellulose containing the agglomerates under reduced pressure.

The obtained fine fibrous cellulose aggregate may be washed with ion-exchanged water. By repeatedly washing the fine fibrous cellulose aggregate with ion-exchanged water, it is possible to remove excess organic onium ions and the like contained in the fine fibrous cellulose aggregate.

The ratio of the content of N atoms to the content of P atoms in the obtained fine fibrous cellulose aggregate (N/P value) is preferably larger than 0.6, and larger than 1.0. More preferable. The ratio of the N atom content to the P atom content (N/P value) in the obtained fine fibrous cellulose aggregate is preferably 5.0 or less. The content of P atoms and the content of N atoms in the fine fibrous cellulose aggregate can be appropriately calculated by elemental analysis. As the elemental analysis, for example, trace nitrogen analysis or molybdenum blue method can be performed after appropriate pretreatment. When the composition other than the fine fibrous cellulose aggregate contains P atoms and N atoms, elemental analysis may be performed after separating the composition and the fine fibrous cellulose aggregate by an appropriate method.

The solid content concentration of the obtained fine fibrous cellulose aggregate is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more. The upper limit of the solid content concentration of the fine fibrous cellulose aggregate is not particularly limited, and may be 100% by mass.

The fine fibrous cellulose aggregate is obtained by drying the fine fibrous cellulose aggregate under constant temperature and humidity conditions. The fine fibrous cellulose concentrate is preferably the fibrous cellulose-containing material of the present invention, but the fine fibrous cellulose aggregate before drying may be the fibrous cellulose-containing material. The temperature for drying the fibrous cellulose aggregate under constant temperature and humidity conditions is preferably 10° C. or higher, and more preferably 20° C. or higher. The temperature under constant temperature and humidity conditions is preferably 100° C. or lower, more preferably 80° C. or lower, and further preferably 60° C. or lower. Further, the relative humidity under constant temperature and constant humidity conditions is preferably 20% or more, and more preferably 30% or more. The relative humidity under constant temperature and humidity conditions is preferably 70% or less. The drying time for drying under constant temperature and humidity conditions is preferably 10 minutes or more, more preferably 20 minutes or more, and further preferably 30 minutes or more. The drying time when drying under constant temperature and constant humidity conditions is preferably 100 hours or less, and more preferably 80 hours or less.

(Fibrous cellulose-containing liquid composition)
The present invention also relates to a fibrous cellulose-containing liquid composition (hereinafter, also simply referred to as a liquid composition) obtained by mixing the above-mentioned fibrous cellulose-containing material and an organic solvent. The liquid composition is a fibrous cellulose-containing dispersion liquid (redispersion liquid) in which the above-mentioned fine fibrous cellulose-containing material is dispersed in a dispersion medium containing an organic solvent.

The organic solvent is not particularly limited, but for example, methanol, ethanol, n-propyl alcohol, isopropyl alcohol (IPA), 1-butanol, m-cresol, glycerin, acetic acid, pyridine, tetrahydrofuran (THF), acetone. , Methyl ethyl ketone (MEK), ethyl acetate, aniline, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), hexane, cyclohexane, benzene, toluene, p-xylene, Examples thereof include diethyl ether chloroform. Among them, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), methyl ethyl ketone (MEK), toluene and methanol are preferably used.

The relative dielectric constant of the organic solvent at 25° C. is preferably 60 or less, and more preferably 50 or less. Since the fibrous cellulose used in the present invention can exhibit excellent dispersibility even in an organic solvent having a low relative dielectric constant, the relative dielectric constant at 25° C. of the organic solvent may be 40 or less. , 30 or less, or 20 or less.

The organic solvent of Hansen Solubility Parameter (Hansen solubility parameter, HSP value) .delta.p of, is preferably 5 MPa ^1/2 or more 20 MPa ^1/2 or less, more preferably 10 MPa ^1/2 or more 19 MPa ^1/2 or less , further preferably 12 MPa ^1/2 or more 18 MPa ^1/2 or less. Further, .delta.h a hydrogen bond of the HSP value is preferably 20 MPa ^1/2 or less, more preferably 15 MPa ^1/2 or less, more preferably 7.5 MPa ^1/2 or less. Further, δh is preferably 1.0 MPa ^1/2 or more.

The content of the organic solvent is preferably 10% by mass or more, and more preferably 50% by mass or more, based on the total mass of the liquid composition. The content of the organic solvent is preferably 99.9% by mass or less, more preferably 99% by mass or less, and even more preferably 95% by mass or less with respect to the total mass of the liquid composition. More preferable.

The dispersion medium of the liquid composition is preferably an organic solvent, but it may further contain water in addition to the organic solvent. The water content of the liquid composition is preferably 0.005% by mass or more, more preferably 0.1% by mass or more, and 3% by mass or more based on the total mass of the liquid composition. Is more preferable. The water content in the liquid composition is preferably 50% by mass or less, more preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total mass of the liquid composition. More preferable.

The solid content concentration in the liquid composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, and more preferably 5% by mass or more, based on the total mass of the liquid composition. More preferable. The solid content concentration in the liquid composition is preferably 90% by mass or less, and more preferably 50% by mass or less, based on the total mass of the liquid composition.

The liquid composition may further contain a resin component. When the resin component is a hydrophilic resin, the solvent of the liquid composition may be an aqueous solvent, and when the resin component is a hydrophobic resin, the solvent of the liquid composition may be an organic solvent. preferable.

The type of resin is not particularly limited, but examples thereof include thermoplastic resins and thermosetting resins. Examples of the resin include acrylic resin, polycarbonate resin, polyester resin, polyamide resin, silicone resin, fluorine resin, chlorine resin, epoxy resin, melamine resin, phenol resin, polyurethane resin, Examples thereof include diallyl phthalate resins, alcohol resins, precursors of these resins, and the like. Among them, the resin is preferably at least one selected from a fluorine resin, a chlorine resin, and an acrylic resin. The type of resin precursor is not particularly limited, but examples thereof include a precursor of a thermoplastic resin or a thermosetting resin. The thermoplastic resin precursor means a monomer or an oligomer having a relatively low molecular weight, which is used for producing the thermoplastic resin. Further, the precursor of the thermosetting resin means a monomer or an oligomer having a relatively low molecular weight, which is capable of forming a thermosetting resin by causing a polymerization reaction or a crosslinking reaction by the action of light, heat and a curing agent.

The liquid composition may further contain, as a resin component, a water-soluble polymer or a water-soluble low molecule in addition to the resin species described above. As the water-soluble polymer, for example, xanthan gum, guar gum, tamarind gum, carrageenan, locust bean gum, quince seed, alginic acid, pullulan, carrageenan, pectin and the like thickening polysaccharides, cationized starch, raw starch, oxidized Starch, etherified starch, esterified starch, starch such as amylose, polyglycerin, hyaluronic acid, metal salts of hyaluronic acid and the like can be mentioned. Examples of the water-soluble low molecule include glycerin and diglycerin.

The liquid composition may further contain other additives. Examples of other additives include antifoaming agents, lubricants, ultraviolet absorbers, dyes, pigments, stabilizers, surfactants, preservatives, and hygroscopic agents. Further, the fibrous cellulose dispersion may contain the hydrophilic polymer, the organic ion or the like as described above as an optional component.

(Molded body)
The present invention also relates to a molded product formed from the above-mentioned fibrous cellulose-containing material or the above-mentioned liquid composition. In the present specification, the term “molded product” refers to a solid product molded into a desired shape or a solid product formed into a sheet. Examples of the molded body include sheets, beads, filaments and the like. Above all, the molded body is preferably a sheet, beads or filament. When the molded product is in the form of beads, the particle diameter of the beads is preferably 0.1 mm or more and 10 mm or less. When the molded product is in the form of a filament, the width of the filament is preferably 0.1 mm or more and 10 mm or less, and the length of the filament is preferably 1 mm or more and 10000 mm or less.

Above all, the molded body is preferably a sheet. When the molded product is a sheet, the tensile modulus of elasticity of the sheet is preferably 4.5 MPa or more, more preferably 5.0 MPa or more, and further preferably 6.0 MPa or more. The tensile modulus of elasticity of the sheet is not particularly limited, but is preferably 20 MPa or less. Here, the tensile elastic modulus of the sheet is a value measured according to JIS P 8113 except that the sheet length is 40 mm and the chuck distance is 20 mm. When measuring the tensile modulus, the sheet is conditioned at 23° C. and a relative humidity of 50% for 24 hours and then measured. As the tensile tester used for the measurement, for example, a tensile tester Tensilon manufactured by A&D Co. can be used. The tensile modulus is a value calculated from the maximum positive slope value in the stress-strain curve (SS curve).

The thickness of the sheet is not particularly limited, but is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. The upper limit of the thickness of the sheet is not particularly limited, but may be, for example, 1000 μm. The thickness of the sheet can be measured by, for example, a stylus thickness meter (Millitron 1202D manufactured by Marl).

The haze of the sheet is, for example, preferably 2% or less, more preferably 1.5% or less, and further preferably 1% or less. On the other hand, the lower limit value of the haze of the sheet is not particularly limited and may be 0%, for example. Here, the haze of the sheet is a value measured by using a haze meter (HM-150 manufactured by Murakami Color Research Laboratory Co., Ltd.) according to JIS K 7136, for example.

The total light transmittance of the sheet is, for example, preferably 85% or more, more preferably 90% or more, and further preferably 91% or more. On the other hand, the upper limit of the total light transmittance of the sheet is not particularly limited and may be 100%, for example. Here, the total light transmittance of the sheet is a value measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K7361.

The basis weight of the sheet is not particularly limited, but is preferably 10 g/m ² or more, more preferably 20 g/m ² or more, and further preferably 30 g/m ² or more. The basis weight of the sheet is not particularly limited, but is preferably 200 g/m ² or less, and more preferably 180 g/m ² or less. Here, the basis weight of the sheet can be calculated in accordance with JIS P 8124, for example.

The density of the sheet is not particularly limited, but is preferably 0.1 g/cm ³ or more, more preferably 0.5 g/cm ³ or more, and further preferably 1.0 g/cm ³ or more. preferable. The density of the sheet is not particularly limited, but is preferably 5.0 g/cm ³ or less, and more preferably 3.0 g/cm ³ or less. Here, the density of the sheet can be calculated by measuring the thickness and mass of the sheet after conditioning the 50 mm square sheet at 23° C. and 50% relative humidity for 24 hours.

The content of fibrous cellulose in the sheet is, for example, preferably 0.5% by mass or more, more preferably 1% by mass or more, and more preferably 5% by mass or more, based on the total mass of the sheet. Is more preferable and 10% by mass or more is particularly preferable. On the other hand, the upper limit of the content of fibrous cellulose in the sheet is not particularly limited, and may be 100% by mass or 95% by mass with respect to the total mass of the sheet.

The sheet may contain a resin component or other additives that may be contained in the liquid composition. Further, the sheet may contain water or an organic solvent.

(Method of manufacturing molded body)
When the molded body is a sheet, the method for manufacturing the molded body includes, as described below, a coating step of coating a fibrous cellulose-containing or liquid composition on a substrate, or a papermaking step of papermaking the slurry. It is preferable to include the above, and above all, it is preferable that the method for producing the molded body includes a coating step of coating the fibrous cellulose-containing material or the liquid composition on the substrate.

<Coating process>
In the coating step, for example, a fibrous cellulose-containing material containing fibrous cellulose or a liquid composition (hereinafter, also simply referred to as a slurry) is coated on a substrate, and a sheet formed by drying this is formed from the substrate. A sheet can be obtained by peeling. Further, the sheet can be continuously produced by using the coating device and the long base material.

The material of the base material used in the coating step is not particularly limited, but a material having higher wettability to the fibrous cellulose-containing material or the liquid composition (slurry) can suppress the shrinkage of the sheet during drying and the like. It is good, but it is preferable to select a sheet from which the sheet formed after drying can be easily peeled off. Of these, a resin film or plate or a metal film or plate is preferable, but not particularly limited. For example, resin films and plates of polypropylene, acrylic, polyethylene terephthalate, vinyl chloride, polystyrene, polycarbonate, polyvinylidene chloride, etc., metal films and plates of aluminum, zinc, copper, iron plates, and those whose surfaces are oxidized. A stainless film or plate, a brass film or plate, or the like can be used.

In the coating process, when the viscosity of the slurry is low and spreads on the base material, a damming frame should be fixed on the base material in order to obtain a sheet with a predetermined thickness and basis weight. May be. The damming frame is not particularly limited, but it is preferable to select, for example, a frame in which the edge of the sheet attached after drying can be easily peeled off. From this point of view, a molded resin plate or metal plate is more preferable. In the present embodiment, for example, a polypropylene plate, an acrylic plate, a polyethylene terephthalate plate, a vinyl chloride plate, a polystyrene plate, a polycarbonate plate, a resin plate such as a polyvinylidene chloride plate, or a metal plate such as an aluminum plate, a zinc plate, a copper plate, or an iron plate. It is also possible to use those whose surfaces are oxidized and which are molded stainless steel plates, brass plates and the like. The coating machine for coating the slurry on the base material is not particularly limited, but a roll coater, a gravure coater, a die coater, a curtain coater, an air doctor coater or the like can be used. A die coater, a curtain coater, and a spray coater are particularly preferable because the thickness of the sheet can be made more uniform.

The slurry temperature and the ambient temperature when applying the slurry to the substrate are not particularly limited, but are preferably 5° C. or higher and 80° C. or lower, more preferably 10° C. or higher and 60° C. or lower, and 15° C. The temperature is more preferably 50° C. or lower and more preferably 20° C. or higher and 40° C. or lower. When the coating temperature is at least the above lower limit, the slurry can be coated more easily. If the coating temperature is at most the above upper limit, volatilization of the dispersion medium during coating can be suppressed.

In the coating step, the slurry is used so that the finished basis weight of the sheet is preferably 10 g/m ² or more and 200 g/m ² or less, more preferably 20 g/m ² or more and 180 g/m ² or less. It is preferable to coat the material. By coating so that the basis weight is within the above range, a sheet having excellent strength can be obtained.

As described above, the coating step includes a step of drying the slurry coated on the base material. The step of drying the slurry is not particularly limited, but is performed by, for example, a non-contact drying method, a method of drying while restraining the sheet, or a combination thereof.

The non-contact drying method is not particularly limited, but for example, a method of heating and drying with hot air, infrared rays, far infrared rays or near infrared rays (heating drying method) or a method of drying in vacuum (vacuum drying method) is applied. can do. The heat drying method and the vacuum drying method may be combined, but the heat drying method is usually applied. Drying with infrared rays, far infrared rays, or near infrared rays is not particularly limited, but can be performed using, for example, an infrared device, a far infrared device, or a near infrared device.

The heating temperature in the heating and drying method is not particularly limited, but is preferably 20° C. or higher and 150° C. or lower, and more preferably 25° C. or higher and 105° C. or lower. When the heating temperature is at least the above lower limit, the dispersion medium can be volatilized quickly. When the heating temperature is at most the above upper limit, it is possible to suppress the cost required for heating and suppress the discoloration of fibrous cellulose due to heat.

<Papermaking process>
The papermaking process is performed by making the slurry into paper using a paper machine. The paper machine used in the paper making process is not particularly limited, and examples thereof include a fourdrinier type, cylinder type, inclined type and the like continuous paper machine, and a multi-layered paper machine combining them. In the paper making process, a known paper making method such as hand making may be adopted.

The papermaking step is performed by filtering the slurry with a wire and dehydrating it to obtain a wet paper sheet, and then pressing and drying this sheet. The filter cloth used for filtering and dehydrating the slurry is not particularly limited, but it is more preferable that, for example, fibrous cellulose does not pass through and the filtration rate does not become too slow. The filter cloth is not particularly limited, but a sheet, a woven fabric, and a porous membrane made of an organic polymer are preferable. The organic polymer is not particularly limited, but non-cellulosic organic polymers such as polyethylene terephthalate, polyethylene, polypropylene and polytetrafluoroethylene (PTFE) are preferable. In the present embodiment, for example, a polytetrafluoroethylene porous film having a pore diameter of 0.1 μm or more and 20 μm or less, a polyethylene terephthalate or polyethylene woven fabric having a pore diameter of 0.1 μm or more and 20 μm or less, and the like can be mentioned.

In the sheet-forming step, a method for producing a sheet from the slurry includes, for example, discharging a slurry containing fibrous cellulose onto the upper surface of an endless belt, and squeezing a dispersion medium from the discharged slurry to form a web. , A drying section for drying the web to produce a sheet. An endless belt is arranged from the water squeezing section to the drying section, and the web produced in the water squeezing section is conveyed to the drying section while being placed on the endless belt.

The dehydration method used in the papermaking step is not particularly limited, and examples thereof include a dehydration method commonly used in paper production. Among these, a method of dehydrating with a Fourdrinier, a cylinder, an inclined wire or the like, and then further dehydrating with a roll press is preferable. The drying method used in the papermaking step is not particularly limited, and examples thereof include the method used in paper production. Among these, a drying method using a cylinder dryer, a Yankee dryer, hot air drying, a near infrared heater, an infrared heater or the like is more preferable.

(Use)
The fibrous cellulose-containing material of the present invention is preferably used for mixing an organic solvent. That is, it can be used as a thickener or a particle dispersion stabilizer for a system containing an organic solvent. By mixing the fine fibrous cellulose of the present invention with an organic solvent, a sheet in which the fine fibrous cellulose is uniformly dispersed can be formed. Further, the fibrous cellulose-containing material of the present invention can be preferably used for mixing with an organic solvent containing a resin component. By mixing the fine fibrous cellulose of the present invention and an organic solvent containing a resin component, it is possible to form a resin composite in which the fine fibrous cellulose is uniformly dispersed. Similarly, a fine fibrous cellulose redispersion slurry is used to form a film, which can be used as various films.

Further, the fibrous cellulose-containing material of the present invention can be used as a reinforcing agent or an additive in cement, paint, ink, lubricant, etc. Further, a molded product obtained by applying a fibrous cellulose-containing material onto a substrate is a reinforcing material, an interior material, an exterior material, a packaging material, an electronic material, an optical material, an acoustic material, a process material, a transportation device. It is also suitable for use as a member, a member of electronic equipment, a member of an electrochemical element, and the like.

The features of the present invention will be described more specifically below with reference to Examples and Comparative Examples. The materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the following specific examples.

<Production Example 1>
[Production of Fine Fibrous Cellulose Dispersion A]
As a raw material pulp, a softwood kraft pulp made by Oji Paper Co., Ltd. (solid content 93% by mass, basis weight 245 g/m ² sheet, disaggregated and measured according to JIS P 8121, Canadian Standard Freeness (CSF) is 700 ml) It was used.

This raw material pulp was subjected to phosphorus oxo oxidation treatment as follows. First, a mixed aqueous solution of phosphorous acid (phosphonic acid) and urea is added to 100 parts by mass of the raw material pulp (absolute dry mass) to form 33 parts by mass of phosphorous acid (phosphonic acid), 120 parts by mass of urea, and 150 parts of water. The pulp was prepared so as to be part by mass to obtain a chemical solution-impregnated pulp. Next, the obtained chemical-solution-impregnated pulp was heated with a hot air dryer at 165° C. for 250 seconds to introduce a phosphorus oxo acid group into cellulose in the pulp to obtain phosphorus oxo oxidized pulp 1.

Then, the phosphorous oxidization pulp 1 thus obtained was washed. In the washing treatment, a pulp dispersion obtained by pouring 10 L of ion-exchanged water to 100 g (absolute dry mass) of phosphorus oxo-oxidized pulp 1 is stirred to uniformly disperse the pulp, and then filtration dehydration is repeated. I went by. When the electric conductivity of the filtrate became 100 μS/cm or less, the washing end point was set.

Then, the washed phosphorous oxidative pulp 1 was subjected to a neutralization treatment as follows. First, the washed phosphorous oxide pulp 1 is diluted with 10 L of ion-exchanged water, and 1N aqueous sodium hydroxide solution is added little by little while stirring to give a phosphorous oxide pulp slurry 1 having a pH of 12 or more and 13 or less. Obtained. Then, the phosphorus oxo-oxidized pulp slurry 1 was dehydrated to obtain a neutralized phosphorus-oxo-oxidized pulp 1. Next, the above-mentioned washing treatment was performed on the phosphorous oxidization pulp 1 after the neutralization treatment.

Infrared absorption spectrum of the thus-obtained phosphoroxoxidized pulp 1 was measured using FT-IR. As a result, the absorption based on P=O of the phosphonic acid group, which is a tautomer of the phosphorous acid group, was observed near 1210 cm ^-1 , and the phosphorous acid group (phosphonic acid group) was added to the pulp. Was confirmed.

Moreover, when the obtained phosphorus oxo-oxidized pulp 1 was tested and analyzed by an X-ray diffractometer, two positions of 2θ=14° or more and 17° or less and 2θ=22° or more and 23° or less were determined. Was confirmed to have a typical peak, and it was confirmed to have a cellulose type I crystal.

Ion-exchanged water was added to the obtained phosphorous oxide pulp 1 to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated with a wet atomizer (Star Burst, manufactured by Sugino Machine Ltd.) 6 times at a pressure of 200 MPa to obtain a fine fibrous cellulose dispersion A containing fine fibrous cellulose.

It was confirmed by X-ray diffraction that the obtained fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured with a transmission electron microscope and found to be 3 to 5 nm. The obtained fine fibrous cellulose was measured for the amount of first dissociated acid by the measuring method described in [Measurement of amount of first dissociated acid and total amount of dissociated acid (phosphorus oxo acid group)] described below. The amount of dissociated acid was 1.51 mmol/g. The total amount of dissociated acid was 1.55 mmol/g.

<Production Example 2>
[Production of fine fibrous cellulose dispersion B]
Phosphorus oxooxidized pulp 2 and fine fibrous cellulose dispersion liquid B were obtained in the same manner as in Production Example 1 except that the heating time in the phosphorous oxidation treatment was 400 seconds. Infrared absorption spectrum of phosphorooxidized pulp 2 was measured using FT-IR. As a result, the absorption based on P=O of the phosphonic acid group, which is a tautomer of the phosphorous acid group, was observed near 1210 cm ^-1 , and the phosphorous acid group (phosphonic acid group) was added to the pulp. Was confirmed. The obtained fine fibrous cellulose was measured for the amount of first dissociated acid by the measuring method described in [Measurement of amount of first dissociated acid and total amount of dissociated acid (phosphorus oxo acid group)] described below. The amount of dissociated acid was 1.86 mmol/g. The total amount of dissociated acid was 1.91 mmol/g.

<Production Example 3>
[Production of fine fibrous cellulose dispersion C]
Phosphorous acid oxidation pulp 3 and fine fibrous form were produced in the same manner as in Production Example 1 except that 28 parts by mass of phosphoric acid and 8 parts by mass of phosphorous acid (phosphonic acid) were used instead of 33 parts by mass of phosphorous acid (phosphonic acid). A cellulose dispersion C was obtained. Infrared absorption spectrum of Phosphorus Oxidized Pulp 3 was measured by FT-IR. As a result, absorption based on P = O phosphonic acid group is a tautomer of phosphorous acid in the vicinity of 1210cm ^-1, absorption based on P = O of phosphate groups was observed around 1230 cm ^-1, pulp It was confirmed that a phosphorous acid group (phosphonic acid group) and a phosphoric acid group were added to. The obtained fine fibrous cellulose was measured for the amount of first dissociated acid by the measuring method described in [Measurement of amount of first dissociated acid and total amount of dissociated acid (phosphorus oxo acid group)] described below. The amount of dissociated acid was 1.60 mmol/g. The total amount of dissociated acid was 2.25 mmol/g.

<Production Example 4>
[Production of fine fibrous cellulose dispersion D]
Instead of 33 parts by mass of phosphorous acid (phosphonic acid), 44 parts by mass of ammonium dihydrogen phosphate was used, the heating time in the phosphoro-oxidation treatment was set to 200 seconds, and the phosphorous-oxidation treatment and the cleaning treatment were added once in this order. The same operation as in Production Example 1 was carried out except that it was carried out to obtain phosphorous oxoxidized pulp 4 and fine fibrous cellulose dispersion liquid D. Infrared absorption spectrum of phosphorooxidized pulp 4 was measured using FT-IR. As a result, absorption based on P=O of the phosphate group was observed near 1230 cm ^-1 , and it was confirmed that the phosphate group was added to the pulp. The obtained fine fibrous cellulose was measured for the amount of first dissociated acid by the measuring method described in [Measurement of amount of first dissociated acid and total amount of dissociated acid (phosphorus oxo acid group)] described below. The amount of dissociated acid was 2.00 mmol/g. The total amount of dissociated acid was 3.30 mmol/g.

<Production Example 5>
[Production of Fine Fibrous Cellulose Dispersion E]
Phosphorus oxoxidized pulp 5 and fine fibrous cellulose dispersion E were obtained in the same manner as in Production Example 4 except that the phosphorus oxo oxidation treatment and the washing treatment were not additionally performed once each. The infrared absorption spectrum of the phosphorous oxide pulp 5 was measured using FT-IR. As a result, absorption based on P=O of the phosphate group was observed near 1230 cm ^-1 , and it was confirmed that the phosphate group was added to the pulp. The obtained fine fibrous cellulose was measured for the amount of first dissociated acid by the measuring method described in [Measurement of amount of first dissociated acid and total amount of dissociated acid (phosphorus oxo acid group)] described below. The amount of dissociated acid was 1.45 mmol/g. The total dissociated acid amount was 2.45 mmol/g.

<Production Example 6>
[Production of fine fibrous cellulose dispersion F]
Phosphorus oxooxidized pulp 6 and fine fibrous cellulose dispersion liquid F were obtained in the same manner as in Production Example 5 except that the heating time in the phosphorous oxidization treatment was 150 seconds. Infrared absorption spectrum of phosphorooxidized pulp 6 was measured using FT-IR. As a result, absorption based on P=O of the phosphate group was observed near 1230 cm ^-1 , and it was confirmed that the phosphate group was added to the pulp. The obtained fine fibrous cellulose was measured for the amount of first dissociated acid by the measuring method described in [Measurement of amount of first dissociated acid and total amount of dissociated acid (phosphorus oxo acid group)] described below. The amount of dissociated acid was 1.10 mmol/g. The total dissociated acid amount was 1.85 mmol/g.

<Production Example 7>
[Production of Fine Fibrous Cellulose Dispersion G]
As a raw material pulp, a softwood kraft pulp made by Oji Paper Co., Ltd. (solid content 93 mass %, basis weight 208 g/m ² sheet shape, Canadian standard freeness (CSF) 700 ml which is disaggregated and measured according to JIS P 8121) It was used. This raw pulp was subjected to TEMPO oxidation treatment as follows.

First, the raw material pulp equivalent to 100 parts by mass of dry mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), 10 parts by mass of sodium bromide, and 10000 parts by mass of water. Dispersed in parts. Then, a 13 mass% sodium hypochlorite aqueous solution was added to 10 g of 1.0 g of pulp to start the reaction. During the reaction, a 0.5 M aqueous sodium hydroxide solution was added dropwise to maintain the pH at 10 or more and 10.5 or less, and the reaction was considered to be complete when no change in pH was observed.

Next, the obtained TEMPO oxidized pulp was washed. The washing treatment is performed by dewatering the pulp slurry after TEMPO oxidation to obtain a dewatering sheet, and then pouring 5000 parts by mass of ion-exchanged water, stirring and uniformly dispersing, and then repeating the operation of filtering and dewatering. It was When the electric conductivity of the filtrate became 100 μS/cm or less, the washing end point was set.

Moreover, when the obtained TEMPO oxidized pulp was tested and analyzed by an X-ray diffractometer, it was found to be at two positions of 2θ=14° or more and 17° or less and 2θ=22° or more and 23° or less. A typical peak was confirmed and it was confirmed to have a cellulose type I crystal.

Ion-exchanged water was added to the obtained TEMPO oxidized pulp to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated with a wet atomizer (Starburst manufactured by Sugino Machine Ltd.) at a pressure of 200 MPa six times to obtain a fine fibrous cellulose dispersion G containing fine fibrous cellulose.

It was confirmed by X-ray diffraction that the fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured with a transmission electron microscope and found to be 3 to 5 nm. Regarding the obtained fine fibrous cellulose, the amount of carboxy groups measured by the measuring method described in [Measurement of total dissociated acid amount (carboxy groups)] described later was 1.80 mmol/g.

<Example 1>
[Production of fine fibrous cellulose concentrate]
0.28 g of lactic acid was added to 100 g of an N,N-didodecylmethylamine aqueous solution of 1.12% by mass to neutralize it in advance, and then added to 100 g of the fine fibrous cellulose dispersion A obtained in Production Example 1. Then, when the mixture was stirred for 5 minutes, aggregates were generated in the fine fibrous cellulose dispersion liquid. A fine fibrous cellulose aggregate was obtained by filtering the fine fibrous cellulose dispersion liquid in which the aggregate was generated under reduced pressure. By repeatedly washing the obtained fine fibrous cellulose aggregate with ion-exchanged water, excess N,N-didodecylmethylamine, lactic acid, eluted ions and the like contained in the fine fibrous cellulose aggregate were removed. The obtained fine fibrous cellulose aggregate was dried under the conditions of 30° C. and a relative humidity of 40% to obtain a fine fibrous cellulose concentrate (fibrous cellulose-containing material). The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 91% by mass.

[Redispersion of fine fibrous cellulose concentrate]
N-methyl-2-pyrrolidone (NMP) was added to the fine fibrous cellulose concentrate so that the fine fibrous cellulose content was 2.0% by mass. Thereafter, ultrasonic treatment was performed for 10 minutes using an ultrasonic treatment device (UP400S manufactured by Hielscher) to obtain a fine fibrous cellulose redispersion slurry. The viscosity of the obtained fine fibrous cellulose redispersion slurry was measured by the method described below.

[Production of sheet containing fine fibrous cellulose]
The obtained fine fibrous cellulose redispersion slurry was drowned in a glass petri dish so that the basis weight was 80 g/m ^2, and was cast and dried on a hot plate at 120° C. for 6 hours to obtain a fine fibrous cellulose-containing sheet. The elastic modulus of the obtained sheet containing fine fibrous cellulose was measured by the method described below.

<Example 2>
100 g of 1.78 mass% di-n-alkyldimethylammonium chloride aqueous solution (the number of carbon atoms in the alkyl chain is 16 or 18) was used in place of the N,N-didodecylmethylamine aqueous solution neutralized with lactic acid. In addition, when re-dispersing the concentrate, it was added to toluene so that the content of fine fibrous cellulose was 4.0% by mass, and the temperature of the cast drying was 40° C. In the same manner as in Example 1, a fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was di-n-alkyldimethylammonium (DADMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 90% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Example 3>
100 g of 0.84 mass% polyoxyethylene dodecylamine (the number of oxyethylene residues is 2) aqueous solution was used instead of the N,N-didodecylmethylamine aqueous solution, and dimethyl was used instead of N-methyl-2-pyrrolidone (NMP). A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained in the same manner as in Example 1 except that sulfoxide (DMSO) was used. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecyl ammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 92% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Example 4>
100 g of a 1.08% by mass aqueous solution of alkyldimethylbenzylammonium chloride (the number of carbon atoms in the alkyl chain is 8 to 18) was used instead of the aqueous solution of N,N-didodecylmethylamine neutralized with lactic acid. Fine fibrous cellulose concentrate, fine fibrous cellulose redispersion slurry, and fine fibers were obtained in the same manner as in Example 1 except that methanol was used instead of 2-pyrrolidone (NMP), and the temperature of cast drying was 50°C. A sheet containing cellulose was obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was alkyldimethylbenzylammonium (ADMBA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 82% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Example 5>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used in place of the fine fibrous cellulose dispersion A. In the same manner as in Example 1 except that 0.34 g of lactic acid was added to 100 g of an N,N-didodecylmethylamine aqueous solution of 1.38% by mass to neutralize and then added to the fine fibrous cellulose dispersion liquid B. , A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 92% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Example 6>
The fine fibrous cellulose dispersion liquid C obtained in Production Example 3 was used instead of the fine fibrous cellulose dispersion liquid A. In the same manner as in Example 1 except that 0.39 g of lactic acid was added to 100 g of a 1.59 mass% N,N-didodecylmethylamine aqueous solution to neutralize and then added to the fine fibrous cellulose dispersion C. , A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 93% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Comparative Example 1>
The fine fibrous cellulose dispersion liquid D obtained in Production Example 4 was used in place of the fine fibrous cellulose dispersion liquid A. In the same manner as in Example 1 except that 0.55 g of lactic acid was added to 100 g of a 2.26 mass% N,N-didodecylmethylamine aqueous solution to neutralize and then added to the fine fibrous cellulose dispersion D. , A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 95% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Comparative example 2>
The fine fibrous cellulose dispersion liquid D obtained in Production Example 4 was used in place of the fine fibrous cellulose dispersion liquid A. In the same manner as in Example 2 except that 100 g of a 3.60 mass% di-n-alkyldimethylammonium chloride aqueous solution (having 16 or 18 carbon atoms in the alkyl chain) was added to the fine fibrous cellulose dispersion D. Thus, a fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was di-n-alkyldimethylammonium (DADMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 91% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Comparative example 3>
The fine fibrous cellulose dispersion liquid D obtained in Production Example 4 was used in place of the fine fibrous cellulose dispersion liquid A. Except that 0.55 g of lactic acid was added to 100 g of an aqueous solution of 1.71% by mass of polyoxyethylene dodecylamine (the number of oxyethylene residues is 2) to neutralize and then added to the fine fibrous cellulose dispersion D. In the same manner as in Example 3, a fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecyl ammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 91% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Comparative example 4>
The fine fibrous cellulose dispersion liquid D obtained in Production Example 4 was used in place of the fine fibrous cellulose dispersion liquid A. Fine fibers in the same manner as in Example 4 except that 100 g of a 2.18 mass% aqueous solution of alkyldimethylbenzylammonium chloride (having 8 to 18 carbon atoms in the alkyl chain) was added to the fine fibrous cellulose dispersion D. A cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was alkyldimethylbenzylammonium (ADMBA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 84% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Comparative Example 5>
The fine fibrous cellulose dispersion E obtained in Production Example 5 was used in place of the fine fibrous cellulose dispersion A. In the same manner as in Example 1 except that 0.42 g of lactic acid was added to 100 g of a 1.71% by mass N,N-didodecylmethylamine aqueous solution to neutralize and then added to the fine fibrous cellulose dispersion E. , A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 94% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Comparative example 6>
Comparative Example 1 was repeated except that 0.33 g of lactic acid was added to 100 g of a 1.37% by mass N,N-didodecylmethylamine aqueous solution to neutralize and then added to the fine fibrous cellulose dispersion D. , A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 93% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Comparative Example 7>
The fine fibrous cellulose dispersion liquid F obtained in Production Example 6 was used in place of the fine fibrous cellulose dispersion liquid A. In the same manner as in Example 1 except that 0.34 g of lactic acid was added to 100 g of a 1.24% by mass N,N-didodecylmethylamine aqueous solution to neutralize and then added to the fine fibrous cellulose dispersion liquid F. , A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the phosphorus oxo acid group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 93% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Reference example>
The fine fibrous cellulose dispersion G obtained in Production Example 7 was used in place of the fine fibrous cellulose dispersion A. In the same manner as in Example 1 except that 0.32 g of lactic acid was added to 100 g of a 1.32% by mass N,N-didodecylmethylamine aqueous solution to neutralize and then added to the fine fibrous cellulose dispersion G. , A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersion slurry, and a fine fibrous cellulose-containing sheet were obtained. The counter ion of the carboxy group contained in the fine fibrous cellulose concentrate was N,N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 91% by mass. The viscosity of the re-dispersed slurry of fine fibrous cellulose and the elastic modulus of the sheet containing fine fibrous cellulose were measured by the methods described below.

<Evaluation method>
[Measurement of first dissociated acid amount and total dissociated acid amount (phosphorus acid group)]
The amount of phosphorus oxo acid group of the fine fibrous cellulose is a fibrous substance prepared by diluting a fine fibrous cellulose dispersion liquid containing the target fine fibrous cellulose with ion-exchanged water to a content of 0.2% by mass. The cellulose-containing slurry was treated with an ion exchange resin and then titrated with an alkali for measurement.
The treatment with the ion-exchange resin was carried out by adding 1/10 by volume of a strongly acidic ion-exchange resin (Amber Jet 1024; Organo Co., Ltd., already conditioned) to the above-mentioned fibrous cellulose-containing slurry and performing a shaking treatment for 1 hour. , And the resin and the slurry were separated by pouring onto a mesh having an opening of 90 μm.
In addition, titration using an alkali measures the change in the pH value of the slurry while adding 10 μL of 0.1 N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry after the treatment with the ion exchange resin in 5 seconds. It was done by doing. The titration was performed 15 minutes before the start of titration while blowing nitrogen gas into the slurry. In this neutralization titration, two points at which the increment (the differential value of pH with respect to the amount of alkali added) is maximized are observed in the curve in which the pH measured with respect to the amount of alkali added is plotted. Of these, the maximum point of the increment obtained first after adding alkali is called the first end point, and the maximum point of the increment obtained next is called the second end point (FIG. 1). The amount of alkali required from the start of titration to the first end point becomes equal to the amount of first dissociated acid in the slurry used for titration. Further, the amount of alkali required from the start of titration to the second end point becomes equal to the total amount of dissociated acid in the slurry used for titration. A value obtained by dividing the alkali amount (mmol) required from the start of titration to the first end point by the solid content (g) in the slurry to be titrated was defined as the first dissociated acid amount (mmol/g). A value obtained by dividing the amount of alkali (mmol) required from the start of titration to the second end point by the solid content (g) in the slurry to be titrated was taken as the total dissociated acid amount (mmol/g).

[Measurement of the amount of carboxy group]
The amount of carboxy groups in the fine fibrous cellulose is produced by diluting the fine fibrous cellulose dispersion liquid containing the target fine fibrous cellulose with ion-exchanged water to a content of 0.2% by mass. The contained slurry was treated with an ion exchange resin and then titrated with an alkali to measure.
The treatment with the ion-exchange resin was carried out by adding 1/10 by volume of a strongly acidic ion-exchange resin (Amber Jet 1024; Organo Co., Ltd., already conditioned) to the above-mentioned fibrous cellulose-containing slurry and performing a shaking treatment for 1 hour. , And the resin and the slurry were separated by pouring onto a mesh having an opening of 90 μm.
The titration with alkali was performed by adding 0.1N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry after the treatment with the ion exchange resin and measuring the change in the pH value of the slurry. .. When the change in pH is observed while adding the aqueous sodium hydroxide solution, a titration curve as shown in FIG. 2 is obtained. As shown in FIG. 2, in this neutralization titration, there is one point where the increment (differential value of pH with respect to the amount of alkali added) becomes maximum in the curve plotting pH measured against the amount of alkali added. To be observed. The maximum point of this increment is called the first end point. Here, the area from the start of titration to the first end point in FIG. 2 is referred to as a first area. The amount of alkali required in the first region becomes equal to the amount of carboxy groups in the slurry used for titration. Then, by dividing the alkali amount (mmol) required in the first region of the titration curve by the solid content (g) in the fine fibrous cellulose-containing slurry to be titrated, the introduction amount of the carboxy group (mmol/g) ) Was calculated.
The amount of introduced carboxy groups (mmol/g) is the amount of substituents per 1 g of the mass of fibrous cellulose when the counter ion of the carboxy group is a hydrogen ion (H ⁺ ) (hereinafter, the amount of carboxy groups (acid Type)).

[Measurement of viscosity of liquid composition]
The viscosity of the liquid composition containing fine fibrous cellulose is 2.0% by mass (other than Example 2 and Comparative Example 2) or 4.0% by mass (Example 2 and Comparative Example 2) obtained after the redispersion step. After leaving the fine fibrous cellulose redispersion slurry at 23° C. for 24 hours, the viscosity of the fine fibrous cellulose redispersion slurry is measured using a B-type viscometer (BLOOKFIELD analog viscometer T-LVT). It is the value. The measurement condition was set to 23° C., and the viscosity when rotated at 3 rpm for 3 minutes was measured. The liquid temperature of the dispersion liquid at the time of measurement was 23°C.

[Tensile elastic modulus of sheet]
Tensile elasticity of a fine fibrous cellulose-containing sheet was measured using a tensile tester Tensilon (manufactured by A&D Company) in accordance with JIS P 8113 except that the length of the test piece was 40 mm and the distance between chucks was 20 mm. The rate was measured. The tensile modulus is a value calculated from the maximum positive slope value in the SS curve. When measuring the tensile modulus, a fine fibrous cellulose-containing sheet having the same basis weight, which was conditioned at 23° C. and a relative humidity of 50% for 24 hours, was used as a test piece.

(Calculation of organic onium content)
The organic onium content is the mass of the organic onium ion contained in the fine fibrous cellulose concentrate divided by the absolute dry mass of the fine fibrous cellulose concentrate. That is, the organic onium content was calculated using the following formula.
Organic onium content (mass %)=100×A×M/(B×M+A×(M-23))
A: Mass (g) of organic onium ions generated from the organic onium tested at the time of production,
B: absolute dry mass (g) of fine fibrous cellulose contained in the fine fibrous cellulose dispersion liquid tested at the time of production,
M: Molecular weight of organic onium ion 23 in the calculation formula is the formula weight of sodium ion.

It was found that the liquid composition obtained by redispersing the fibrous cellulose-containing material obtained in the example had a high viscosity, and the fibrous cellulose-containing material had excellent dispersibility. When a sheet was formed using the fibrous cellulose-containing material obtained in the example, a sheet having a high elastic modulus was obtained.

Claims (8)

Contains a fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorus oxo acid group or a substituent derived from the phosphorus oxo acid group, and an organic onium ion as a counter ion of the phosphorus oxo acid group or the substituent derived from the phosphorus oxo acid group. A fibrous cellulose-containing material that
A fibrous cellulose-containing material having a value of A1/A2 of 0.65 or more, where A1 is the first dissociated acid amount in the fibrous cellulose and A2 is the total dissociated acid amount in the fibrous cellulose. A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphite group or a substituent derived from the phosphite group, and an organic onium as a counter ion of the phosphite group or the substituent derived from the phosphite group. A fibrous cellulose-containing material containing ions. The fibrous cellulose-containing material according to claim 1 or 2, wherein the organic onium ion satisfies at least one of the following conditions (a) and (b):
(A) contains a hydrocarbon group having 5 or more carbon atoms;
(B) The total carbon number is 17 or more. The fibrous cellulose-containing material according to any one of claims 1 to 3, wherein the organic onium ion is organic ammonium. Content of the said fibrous cellulose with respect to the total mass of the said fibrous cellulose containing material is 80 mass% or more, Fibrous cellulose containing material as described in any one of Claims 1-4. A fibrous cellulose-containing liquid composition obtained by mixing the fibrous cellulose-containing material according to any one of claims 1 to 5 and an organic solvent. The fibrous cellulose-containing liquid composition according to claim 6, further comprising a resin component. A molded article formed from the fibrous cellulose-containing material according to any one of claims 1 to 5 or the fibrous cellulose-containing liquid composition according to claim 6 or 7.

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