JP6978403B2 - Fibrous cellulose-containing material, fibrous cellulose-containing liquid composition and molded product - Google Patents

Description

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

Conventionally, cellulose fibers have been widely used in clothing, absorbent articles, paper products and the like. As the cellulose fiber, in addition to the 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 also known. Fine fibrous cellulose is attracting attention as a new material, and its uses are wide-ranging. For example, sheets containing fine fibrous cellulose, resin complexes, and thickeners are being developed.

When fine fibrous cellulose is used, for example, as a thickener, a liquid in which fine fibrous cellulose is dispersed is transported to a processing factory or the like. However, since the liquid in which the fine fibrous cellulose is dispersed contains a large amount of dispersion medium, there is a problem that the transportation cost is high. Therefore, in order to reduce the transportation cost, it is desired to make the liquid in which the fine fibrous cellulose is dispersed into a concentrated form as much as possible.

For example, Patent Documents 1 and 2 disclose fibrous cellulose-containing substances (aggregates) containing fine fibrous cellulose and a metal component. In the examples in these documents, a large amount of the multivalent metal component used in the agglutination step remains in the obtained fibrous cellulose-containing material (aggregate). In addition, Patent Document 3 discloses a cellulose fine fiber-containing substance containing a cellulose fine fiber into which an ester of phosphorous acid containing a cation consisting of an inorganic substance is introduced. In the examples of Patent Document 3, a cellulose fiber containing a sodium ion is disclosed as a counterion of a phosphite group, but a metal component as a flocculant is not added, and the fiber is allowed to stand at 105 ° C. for 6 hours. A cellulose fine fiber-containing substance is obtained through a drying step.

International Publication No. 2014/0248776 Japanese Patent No. 6361836 Japanese Patent No. 6404415

As described above, a method of adding a flocculant containing a multivalent metal component to fine fibrous cellulose to obtain a concentrate of fine fibrous cellulose is known. In such a case, it is conceivable to remove the flocculant by washing the obtained concentrate, but there is a problem that the flocculant cannot be completely removed, especially when a flocculant containing a polyvalent metal component is used. ..

Therefore, in order to solve the problems of the prior art, the present inventors have obtained a fibrous cellulose-containing material by adding a flocculant containing a polyvalent metal to a dispersion of fine fibrous cellulose. The study was carried out for the purpose of providing a fibrous cellulose-containing material in which the residual amount of the metal component was reduced.

As a result of diligent studies to solve the above problems, the present inventors have found that the fibrous cellulose-containing material containing fine fibrous cellulose having a phosphoacid group or a substituent derived from the phosphoxoic acid group is fine. When the amount of the first dissociated acid in the fibrous cellulose is A1 and the total amount of the dissociated acid in the fine fibrous cellulose is A2, the value of A1 / A2 is set to 0.65 or more to disperse the fine fibrous cellulose. Even when a fibrous cellulose-containing material is obtained by adding a flocculant containing a polyvalent metal to the liquid, a fibrous cellulose-containing material in which the residual amount of a metal component such as a polyvalent metal is reduced can be obtained. I found.
Specifically, the present invention has the following configurations.

[1] A fibrous cellulose-containing product having a fiber width of 1000 nm or less and containing a phospholic acid group or a fibrous cellulose having a substituent derived from a phosphoxoic acid group and a polyvalent metal.
A fibrous cellulose-containing substance having an A1 / A2 value of 0.65 or more when the first dissociative acid amount in the fibrous cellulose is A1 and the total dissociative acid amount in the fibrous cellulose is A2.
[2] A fibrous cellulose-containing material having a fiber width of 1000 nm or less and containing a phosphite group or a fibrous cellulose having a substituent derived from a phosphite group and a polyvalent metal.
[3] The fibrous cellulose-containing material according to [1] or [2], wherein the total light transmittance measured under the following measurement condition (a) is 95% or more;
Measurement method (a):
Ion-exchanged water is added to the fibrous cellulose-containing material to prepare an aqueous suspension A having a solid content concentration of 0.5% by mass; the pH of the aqueous suspension A is adjusted to 10 and then 2.5 m / sec. Add ion-exchanged water to the obtained water suspension to make the solid content concentration 0.2% by mass, allow it to stand for 24 hours, and then, according to JIS K 7361, have an optical path length of 1 cm. Measure the total light transmittance under the conditions.
[4] The fibrous cellulose-containing material according to any one of [1] to [3], wherein the content of the fibrous cellulose is 5% by mass or more with respect to the total mass of the fibrous cellulose-containing material.
[5] The fibrous cellulose-containing substance according to any one of [1] to [4], which is a solid form.
[6] A fibrous cellulose-containing liquid composition obtained by mixing the fibrous cellulose-containing material according to any one of [1] to [5] with a solvent.
[7] When the solid content concentration in the fibrous cellulose-containing liquid composition is 0.5% by mass or less and the total light transmittance is 95% or more when measured under the condition of an optical path length of 1 cm in accordance with JIS K 7361. The fibrous cellulose-containing liquid composition according to [6].
[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, when a flocculant containing a polyvalent metal is added to a dispersion of fine fibrous cellulose to obtain a fibrous cellulose-containing material, the residual amount of the metal component is reduced. Can be obtained.

FIG. 1 is a graph showing the relationship between the amount of NaOH dropped and the pH of a fibrous cellulose-containing slurry having a phosphoric acid group.

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

(Filamentous cellulose-containing material)
A first aspect of the present invention relates to a fibrous cellulose-containing material having a fiber width of 1000 nm or less and containing a phospholic acid group or a substituent derived from a phosphoxoic acid group and a polyvalent metal. Here, when the amount of the first dissociated acid in the fibrous cellulose is A1 and the total amount of the dissociated acid in the fibrous cellulose is A2, the value of A1 / A2 is 0.65 or more.

A second aspect of the present invention is a fibrous cellulose-containing material having a fiber width of 1000 nm or less and containing a phosphite group or a fibrous cellulose having a substituent derived from the phosphite group and a polyvalent metal. Regarding.

Since the fibrous cellulose-containing material of the present invention has the above-mentioned structure, it contains a polyvalent metal, but the residual amount of the metal component containing the polyvalent metal is reduced. Specifically, when the fibrous cellulose-containing material of the present invention is obtained, the fibrous cellulose-containing material is obtained by adding a flocculant containing a polyvalent metal to the dispersion liquid of the fine fibrous cellulose. In such a case, the residual amount of the metal component including the polyvalent metal can be reduced. Conventionally, when a flocculant containing a polyvalent metal is added to a dispersion of fine fibrous cellulose to obtain a fibrous cellulose-containing material, the flocculant contained in the concentrated fibrous cellulose-containing material (multivalent). In some cases, the metal) could not be completely removed by washing, and a large amount of metal components remained. On the other hand, depending on the use of the concentrated fibrous cellulose-containing material, the remaining metal components such as polyvalent metal may have an adverse effect, so there is a desire to remove the metal components such as polyvalent metal as much as possible. .. Therefore, in the present invention, the configuration of the first aspect and the second aspect described above makes it possible to reduce the residual amount of the metal component in the concentrated fibrous cellulose-containing material.

As described above, the residual amount of the metal component in the fibrous cellulose-containing material of the present invention is small. Specifically, the polyvalent metal content in the fibrous cellulose-containing material is preferably 0.070 mmol / g or less, more preferably 0.060 mmol / g or less, and 0.050 mmol / g or less. It is more preferably present, and particularly preferably 0.045 mmol / g or less. The polyvalent metal content in the fibrous cellulose-containing material is preferably 0.0001 mmol / g or more. Here, the polyvalent metal content in the fibrous cellulose-containing material is the polyvalent metal content (mmol) per 1 g of the solid content of the fibrous cellulose-containing material. Specifically, the amount of polyvalent metal (mmol) is measured by performing ICP-AES measurement on the diluted solution obtained as follows. To obtain a diluted solution to be used for measurement, first, 10 g of the fibrous cellulose-containing material is heated at 525 ° C. to incinerate it, dissolved in 5 mL of 1% nitric acid, and wet-decomposed. Then, after filtering this solution with a filter of 0.45 μm, ultrapure water is added and the volume is adjusted to 50 mL to obtain a diluted solution. By dividing the amount of polyvalent metal (mmol) measured by ICP-AES measurement by the solid content (g) of the fibrous cellulose-containing material tested, the above-mentioned polyvalent metal content (mmol / g) can be obtained. Calculated.

In the present invention, the polyvalent metal content is not more than the above upper limit value, and the content is kept low. However, a part of the polyvalent metal remains as polyvalent metal ions in the fibrous cellulose-containing material. This is because the phosphorus oxo acid group is an anionic group, and at least a part of the polyvalent metal ion forms an ionic bond by electrostatic interaction with the phosphorus oxo acid group, so that a trace amount remains. However, in the present invention, the value of A1 / A2 is set to 0.65 or more, or the fibrous cellulose has a phosphite group or a substituent derived from the phosphite group as a phosphoric acid group. The content of polyvalent metal remaining in the fibrous cellulose-containing material can be reduced as much as possible. As described above, in the fibrous cellulose-containing material of the present invention, the polyvalent metal content is suppressed, so that the polyvalent metal component is contained even when the fibrous cellulose-containing material is processed in a subsequent step, for example. It is possible to suppress the formation of precipitates and the embrittlement of the molded product in the dispersion liquid derived from.

The fibrous cellulose-containing material of the present invention is also excellent in redispersibility in a solvent. Specifically, when the fibrous cellulose-containing material is redispersed in a solvent, no precipitate is formed in the redispersion liquid. Therefore, the slurry obtained by dispersing fine fibrous cellulose in a solvent is highly transparent. For example, the total light transmittance measured under the following measurement condition (a) is preferably 95% or more, and more preferably 96% or more.
Measurement method (a):
Ion-exchanged water is added to the fibrous cellulose-containing material to prepare an aqueous suspension A having a solid content concentration of 0.5% by mass. After adjusting the pH of the aqueous suspension A to 10, the mixture is stirred at 2.5 m / sec for 5 minutes. Ion-exchanged water was added to the obtained aqueous suspension to make the solid content concentration 0.2% by mass, and after allowing to stand for 24 hours, the total light transmittance was set to 1 cm in optical path length in accordance with JIS K 7361. To measure.

In the measuring method (a), when preparing the aqueous suspension A having a solid content concentration of 0.5% by mass, first, the fibrous cellulose-containing substance is added to the ion-exchanged water, and the solid content concentration is 0. Obtain 100 g of a 5% by mass slurry. Then, the obtained slurry is stirred with a magnetic stirrer for 5 minutes to obtain a water suspension A. When adjusting the pH of the aqueous suspension A to 10, 1N sodium hydroxide is added dropwise with the same stirring with a magnetic stirrer. Then, using a disperser, the mixture is stirred at 1500 rpm (2.5 m / s) for 5 minutes, and after 24 hours, the slurry is diluted with ion-exchanged water so that the solid content concentration becomes 0.2% by mass, and the disperser is used. Stir at 1500 rpm (2.5 m / s) for 5 minutes. Then, after defoaming the obtained slurry, it is allowed to stand in an environment of 23 ° C. for 24 hours, and the total light transmittance is measured according to JIS K 7361. As the haze meter used at this time, HM-150 manufactured by Murakami Color Technology Research Institute can be used. Further, when performing the defoaming treatment, a rotation / revolution type super mixer can be used. For example, the defoaming treatment is performed by stirring at 2200 rpm for 2 minutes using ARE-250 manufactured by Shinky Co., Ltd. Can be done. When measuring the total light transmittance, a glass cell for liquid having an optical path length of 1 cm is used, and the zero point measurement is performed with ion-exchanged water contained in the glass cell.

The content of the fibrous cellulose with respect to the total mass of the fibrous cellulose-containing material is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. The upper limit of the content of the fibrous cellulose with respect to the total mass of the fibrous cellulose-containing material is not particularly limited, but may be, for example, 95% by mass. 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 assuming that the counterion of the anionic group of the fibrous cellulose is a hydrogen ion (H ^+). Here, the mass of the fibrous cellulose is the mass of the fibrous cellulose, which is the solid content remaining after the fibrous cellulose is extracted by an appropriate method and undergoes this operation. Examples of the extraction method include a method of selectively extracting a component existing as a counterion of a phosphorus oxo acid group of fine fibrous cellulose as a salt 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 95% by mass or less, more preferably 90% by mass or less, and 85% by mass or less with respect to the total mass of the fibrous cellulose-containing material. It is more preferable to have. Further, the content of water in the fibrous cellulose-containing material may be 0% by mass. The water content in the fibrous cellulose-containing material can be measured by placing 200 mg of the fibrous cellulose-containing material on a moisture meter (MS-70, manufactured by A & D Co., Ltd.) and heating at 140 ° C. 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 the form of a liquid, or may be in the form of a solid or a gel. Above all, the fibrous cellulose-containing material of the present invention is preferably in a solid state. Further, 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 composition for forming a molded body, and preferably a composition for forming a sheet.

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 powder or granule, and more preferably a powder or granule. preferable. Here, the powder or granular material is a powdery and / or granular substance. The powdery substance is smaller than the granular substance. Generally, the powdery substance refers to fine particles having a particle size of 1 nm or more and less than 0.1 mm, and the granular substance refers to particles having a particle size of 0.1 mm or more and 10 mm or less, but is not particularly limited. In the present specification, the powder or granular material may be referred to as powder. The particle size of the powder or granular material in the present specification can be measured and calculated by using a laser diffraction method. Specifically, it is a value measured using a laser diffraction / scattering type particle size distribution measuring device (Microtrac 3300EXII, Nikkiso Co., Ltd.).

(Fibrous cellulose)
The fibrous cellulose-containing material of the present invention contains a phospholic acid group or a fibrous cellulose having a substituent derived from a phosphoxoic 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, for example, by 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. Especially preferable. By setting the average fiber width of the fibrous cellulose to 2 nm or more, it is possible to suppress the dissolution of the cellulose molecule in water and make it easier to exhibit the effects of the fibrous cellulose on improving strength, rigidity and dimensional stability. can. The fibrous cellulose is, for example, monofibrous cellulose.

The average fiber width of 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 this suspension is cast on a hydrophilized carbon film-coated grid to be a sample for TEM observation. And. If it contains wide fibers, an SEM image of the surface cast on the glass may be observed. Next, observation is performed using an electron microscope image at a magnification of 1000 times, 5000 times, 10000 times, or 50,000 times depending on the width of the fiber to be observed. However, the sample, observation conditions and magnification should be adjusted so as to satisfy the following conditions.
(1) A straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y that intersects the straight line perpendicularly 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 with respect to the observation 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. Next, for each image, the width of the fiber intersecting the straight line X and the straight line Y is read. As a result, at least 20 fibers × 2 × 3 = 120 fibers are read. Then, the average value of the read fiber widths is taken 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, it is possible to suppress the destruction of the crystal region of the fibrous cellulose. It is also possible to set the slurry viscosity of the fibrous cellulose in an appropriate range. The fiber length of the fibrous cellulose can be obtained by, for example, image analysis by TEM, SEM, or AFM.

The fibrous cellulose preferably has an I-type crystal structure. Here, the fact that the fibrous cellulose has an I-type crystal structure can be identified in the diffraction profile obtained from the wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418 Å) monochromatic with graphite. Specifically, it can be identified by having typical peaks at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less. The ratio of the type I crystal structure to the fine fibrous cellulose is, for example, preferably 30% or more, more preferably 40% or more, still more preferably 50% or more. As a result, even better performance can be expected in terms of heat resistance and the development of a low coefficient of linear thermal expansion. The crystallinity is determined by a conventional method from the X-ray diffraction profile measured and the pattern (Seagal et al., Textile Research Journal, Vol. 29, p. 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 value or more, it is easy to form a sheet containing fine fibrous cellulose. By setting the axial ratio to the above upper limit value or less, it is preferable in that handling such as dilution becomes easy when, for example, fibrous cellulose is treated as a dispersion liquid.

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

The fibrous cellulose has a phosphate group or a substituent derived from the 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.

The amount of phosphoxoic acid groups introduced into the fibrous cellulose (the amount of phosphoxoic acid groups) is preferably 0.10 mmol / g or more, and more preferably 0.20 mmol / g or more, for example, per 1 g (mass) of the fibrous cellulose. It is more preferably 0.50 mmol / g or more, and particularly preferably 1.00 mmol / g or more. The amount of the phosphorus oxo acid group introduced into 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. It is more preferably 00 mmol / g or less. Here, the unit mmol / g indicates the amount of substituents per 1 g of mass of fibrous cellulose when the counter ion of the phosphorus oxo acid group is a hydrogen ion (H ^+). By setting the amount of the phosphorus oxo acid group introduced within the above range, it is possible to facilitate the miniaturization of the fiber raw material and enhance the stability of the fibrous cellulose. Furthermore, by setting the amount of the phosphorus oxo acid group introduced within the above range, the dispersibility of the fibrous cellulose in the solvent can be more effectively enhanced.

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

FIG. 1 is a graph showing the relationship between the amount of NaOH dropped and the pH of a fibrous cellulose-containing slurry having a phosphoric acid group. The amount of the phosphorus oxo acid group introduced into the fibrous cellulose is measured, for example, as follows.
First, the slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, the same defibration treatment as the defibration treatment step described later may be performed on the measurement target before the treatment with the strong acid ion exchange resin.
Next, the change in pH is observed while adding an aqueous sodium hydroxide solution, and a titration curve as shown in the upper part of FIG. 1 is obtained. The titration curve shown in the upper part of FIG. 1 plots the measured pH with respect to the amount of alkali added, and the titration curve shown in the lower part of FIG. 1 plots the pH with respect to the amount of alkali added. The increment (differential value) (1 / mmol) is plotted. In this neutralization titration, two points are confirmed in which the increment (differential value of pH with respect to the amount of alkaline drop) becomes maximum in the curve plotting the measured pH with respect to the amount of alkali added. Of these, the maximum point of the increment obtained first when alkali is added is called the first end point, and the maximum point of the increment obtained next is called the second end point. The amount of alkali required from the start of titration to the first end point is equal to the amount of first dissociated acid of the fibrous cellulose contained in the slurry used for titration, and the amount of alkali required from the first end point to the second end point. The amount is equal to the amount of the second dissociating 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 is the total amount of the dissociating acid in the slurry used for the titration. Will be equal. Then, 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 amount of phosphorus oxo acid group introduced (mmol / g). The amount of phosphorus oxo acid group introduced (or the amount of phosphorus oxo acid group) simply means the amount of the first dissociated acid.
In FIG. 1, the region from the start of titration to the first end point is referred to as a first region, and the region from the first end point to the second end point is referred to as a second region. For example, when the phosphoric acid group is a phosphoric acid group and the phosphoric acid group causes condensation, the amount of weakly acidic groups in the phosphoric acid group (also referred to as the second dissociated acid amount in the present specification) is apparently. It decreases, and the amount of alkali required for the second region is smaller than the amount of alkali required for the first region. On the other hand, the amount of strongly acidic groups in the phosphorus oxo acid group (also referred to as the first dissociated acid amount in the present specification) is the same as the amount of phosphorus atoms regardless of the presence or absence of condensation. When the phosphorous acid group is a phosphorous acid group, the weakly acidic group does not exist in the phosphorous acid group, so that the amount of alkali required for the second region is reduced or the amount of alkali required for the second region is reduced. May be zero. In this case, there is only one point on the titration curve where the pH increment is maximum.

In the measurement of the amount of phosphorus oxo acid groups by the titration method, accurate values such as when the amount of one drop of sodium hydroxide aqueous solution is too large or when the titration interval is too short, the amount of phosphorus oxo acid groups is lower than originally obtained. It may not be obtained. As an appropriate dropping amount and titration interval, for example, it is desirable to titrate 10 to 50 μL of a 0.1 N sodium hydroxide aqueous solution every 5 to 30 seconds. Further, 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 from 15 minutes before the start of titration.

In the first aspect of the present invention, when the first dissociative acid amount (mmol / g) in the fibrous cellulose is A1 and the total dissociation acid amount (mmol / g) in the fibrous cellulose is A2, it is A1 / A2. The value may be 0.65 or more, preferably 0.68 or more, more preferably 0.70 or more, and even more preferably 0.80 or more. Further, the upper limit of the values of A1 / A2 is preferably 1.00. Here, the amount of the first dissociating acid (A1) in the fibrous cellulose is the amount of alkali (mmol) required from the start to the first end point of the titration in the above-mentioned titration curve, and the solid content (g) in the slurry to be titrated. ) Divided by. That is, the first dissociated acid amount (A1) is a value obtained by dividing the substance amount (mmol) of the acid that is ionized and neutralized in the first step by the solid content (g) in the slurry to be titrated. 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 slurry to be titrated. 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 and neutralized at all stages by the solid content (g) in the slurry to be titrated. Therefore, the closer the value of A1 / A2 is to 1, the smaller the amount of weak acid (such as the amount of weakly acidic group in the phosphorus oxo acid group). In the first aspect of the present invention, by setting the value of A1 / A2 within the above range, a flocculant containing a polyvalent metal is added to the dispersion liquid of fine fibrous cellulose to obtain a fibrous cellulose-containing substance. Even in this case, it is possible to obtain a fibrous cellulose-containing material in which the residual amount of the metal component is reduced.

The value of A1 / A2 approaches 1 in both cases when the phosphate group is condensed and when the phosphite group is present. As a method for determining whether the factor that causes A1 / A2 to approach 1 is the condensation of a phosphoric acid group or the presence of a phosphite group, for example, a phosphoric acid condensation structure such as acid hydrolysis is used. Examples thereof include a method of performing the above-mentioned titration operation after performing a cutting treatment, and 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 phosphate group or the substituent derived from the phosphorusoxo 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 (for example, a pyrophosphate group) in which the phosphorus oxo acid group is condensed.

In the formula (1), a, b and n are natural numbers, and m is an arbitrary number (where a = b × m). ^{α 1, α 2, ···,} a number of alpha ⁿ and alpha 'is O ^- a and the remainder is either R, the OR. Here, R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, or an unsaturated-branched chain. A hydrocarbon group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or an inducing group thereof. R may be a group derived from a cellulose molecular chain. Among ^{them, either α n} or α'is preferably R, and it is particularly preferable that R is a hydrogen atom. Further, n is preferably 1. That is, the phosphoric acid group or the substituent derived from the phosphoric acid group is preferably a phosphite group or a substituent derived from the phosphite group.

In the second aspect of the present invention, the fibrous cellulose has a phosphite group or a substituent derived from the phosphite group. That is, in the equation (1), a of α ⁿ and α'are O ⁻ , and ^{either α n} or α'is R. Above all, R is preferably a hydrogen atom.

In addition, a part of the substituent derived from a phosphoric acid group or a phosphoric acid group may be a phosphoric acid group or a substituent derived from a phosphoric acid group, or a group in which a phosphoric acid group is condensed (for example, pyrophosphate). It may be a group). As described above, the fibrous cellulose has a phosphite group or a substituent derived from a phosphite group (hereinafter, also simply referred to as a phosphite group) and a phosphate group or a substituent derived from a phosphate group (hereinafter, simply referred to as a phosphite group). , Simply referred to as a phosphate group), the proportion of the subphosphate group among the substituents represented by the formula (1) is preferably 30% by mass or more, preferably 40% by mass. % Or more, 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, an n-butyl group and the like, but are not particularly limited. Examples of the saturated-branched chain hydrocarbon group include an i-propyl group and a t-butyl group, but the group is not particularly limited. Examples of the saturated-cyclic hydrocarbon group include, but are not limited to, a cyclopentyl group, a cyclohexyl group and the like. Examples of the unsaturated-linear hydrocarbon group include, but are not limited to, a vinyl group, an allyl group and the like. Examples of the unsaturated-branched chain hydrocarbon group include an i-propenyl group and a 3-butenyl group, but the group is not particularly limited. Examples of the unsaturated-cyclic hydrocarbon group include, but are not limited to, a cyclopentenyl group, a cyclohexenyl group and the like. Examples of the aromatic group include, but are not limited to, a phenyl group, a naphthyl group and the like.

Further, as the inducing group in R, 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 with respect to the main chain or side chain of the above-mentioned various hydrocarbon groups. The group is mentioned, but is not particularly limited. The number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, and more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R to the above range, the molecular weight of the phosphorus oxo acid group can be set to an appropriate range, the penetration into the fiber raw material is facilitated, and the yield of the fine cellulose fiber is increased. You can also do it.

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 or aromatic ammonium, and examples of monovalent or higher valent cations composed of inorganic substances include ions of alkali metals such as sodium, potassium, and lithium. Examples thereof include cations of divalent metals such as calcium and magnesium, hydrogen ions and the like, but the present invention is not particularly limited. These may be applied alone or in combination of two or more. The monovalent or higher cation composed of an organic substance or an inorganic substance is preferably sodium or potassium ion which is hard to yellow when the fiber raw material containing β is heated and is easily industrially used, but is not particularly limited.

The fact that fibrous cellulose has a phosphite group as a substituent means that the infrared absorption spectrum of the dispersion containing fibrillar cellulose is measured, and phosphon, which is a metamorphic form of the phosphite group ^{, is measured around 1210 cm -1.} It can be confirmed by observing the absorption of the acid group based on P = O. Further, the fact that fibrous cellulose has 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.

In addition, the fibrous cellulose may have another anionic group in addition to the phosphoxoic acid group or the substituent derived from the phosphoxoic acid group. Examples of such anionic groups include carboxy groups originally contained in pulp.

<Manufacturing process of fine fibrous cellulose>
<Fiber raw material>
Fine fibrous cellulose is produced 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. Examples of pulp include wood pulp, non-wood pulp, and deinked pulp. The wood pulp is not particularly limited, but is, for example, broadleaf kraft pulp (LBKP), coniferous kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), and 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), crushed wood pulp (GP) and thermomechanical pulp (TMP, BCTMP), etc. Examples include mechanical pulp. The non-wood pulp is not particularly limited, and examples thereof include cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as hemp, straw and bagasse. The deinking pulp is not particularly limited, and examples thereof include deinking pulp made from recycled paper. As the pulp of this embodiment, one of the above may be used alone, or two or more of them may be mixed and used. Among the above pulps, for example, wood pulp and deinked pulp are preferable from the viewpoint of availability. Further, among wood pulps, it is possible to obtain long-fiber fine fibrous cellulose having a large cellulose ratio and a high yield of fine fibrous cellulose during defibration treatment, and having a small decomposition of cellulose in the pulp and a large axial ratio. From the viewpoint, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are further preferable. It should be noted that the viscosity tends to be high when the 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 and bacterial cellulose produced by acetic acid bacteria can also 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 can also be used.

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

In the phosphorus oxo acid group introduction step according to the present embodiment, the reaction between the fiber raw material containing cellulose and compound A is carried out in the presence of at least one selected from urea and its derivatives (hereinafter, also referred to as “compound B”). You may. On the other hand, the reaction of the fiber raw material containing cellulose with the compound A may be carried out in the absence of the compound B.

As an example of the method of allowing the compound A to act on the fiber raw material in the coexistence with the compound B, there is 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. Of these, since the reaction uniformity is high, it is preferable to use a fiber raw material in a dry state or a wet state, and it is particularly preferable to use a fiber raw material in a dry state. The form of the fiber raw material is not particularly limited, but is preferably cotton-like or thin sheet-like, for example. Examples of the compound A and the compound B include a method of adding the compound A and the compound B to the fiber raw material in the form of a powder or a solution dissolved in a solvent, or in a state of being heated to a melting point or higher and melted. Of these, since the reaction uniformity is high, it is preferable to add the solution 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 for 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 immersed in the solution to absorb the liquid and then taken out, or the fiber raw material may be taken out. The solution may be dropped into the water. Further, a required amount of compound A and compound B may be added to the fiber raw material, or an excess amount of compound A and compound B may be added to the fiber raw material, respectively, and then the surplus compound A and compound B may be added by pressing or filtering. It 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, and the compound A contains at least a compound having a phosphorous acid group and / or a salt thereof. .. Examples of the compound having a phosphite group include phosphite, and examples of the phosphite include 99% phosphoric acid (phosphonic acid). Examples of the salt of phosphite include a lithium salt of phosphite, a sodium salt, a potassium salt, an ammonium salt and the like, and these can have various neutralization degrees. Of these, from the viewpoints that the efficiency of introducing a phosphoric acid group is high, the defibration efficiency is more likely to be improved in the defibration step described later, the cost is low, and it is easy to apply industrially, phosphoric acid and phosphite are easily applied. A sodium salt of acid, a potassium salt of phosphoric acid, or an ammonium salt of phosphoric acid is preferable, and phosphoric acid is more preferable. In addition, the compound A includes a compound having a phosphoric acid group and / or a salt thereof, a compound having a phosphoric acid group and / or a salt thereof, a dehydration condensed phosphoric acid and / or a salt thereof, and an anhydrous phosphoric acid (pentoxide). Dirin) and the like may be included. In this case, as the phosphoric acid, those having various puritys can be used, and for example, 100% phosphoric acid (normal phosphoric acid) or 85% phosphoric acid can be used. The dehydration-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 amount of compound A added to the fiber raw material is not particularly limited, but for example, when the amount of compound A added is converted to the phosphorus atomic weight, the amount of phosphorus atom added 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, and further preferably 2% by mass or more and 30% by mass or less. By setting the amount of phosphorus atom 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 setting the addition amount of the phosphorus atom to the fiber raw material to be equal to or less than the above upper limit value, 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 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, compound B is preferably used as an aqueous solution. Further, from the viewpoint of further improving the uniformity of the reaction, it is preferable to use an aqueous solution in which both compound A and compound B are dissolved.

The amount of 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, and more preferably 10% by mass or more and 400% by mass or less. It is more preferably 100% by mass or more and 350% by mass or less.

In the reaction between the fiber raw material containing cellulose and compound A, for example, amides or amines may be contained in the reaction system in addition to compound B. 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, hexamethylenediamine and the like. Among these, triethylamine in particular is known to act as a good reaction catalyst.

In the phosphorus oxo acid group introduction step, it is preferable to add or mix the compound A or the like to the fiber raw material and then heat-treat the fiber raw material. As the heat treatment temperature, it is preferable to select a temperature at which a phosphorus oxo acid group can be efficiently introduced while suppressing the 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. In addition, equipment having various heat media can be used for the heat treatment, for example, a stirring drying device, a rotary drying device, a disk drying device, a roll type heating device, a plate type heating device, a fluidized layer drying device, and an air flow. A drying device, a vacuum 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 a method of 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 compound A in the fiber raw material and to more uniformly introduce the phosphoric acid group onto the surface of the cellulose fiber contained in the fiber raw material. This is because when the 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 also moves to the surface of the fiber raw material (that is, the concentration unevenness of the compound A is caused. It is considered that this is due to the fact that it can be suppressed.

Further, the heating device used for the heat treatment always keeps the water content retained by the slurry and the water content generated by the dehydration condensation (phosphate esterification) reaction between the compound A and the hydroxyl group 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. Examples of such a heating device include a ventilation type oven and the like. By constantly discharging the water in the apparatus system, it is possible to suppress the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the phosphate esterification, and also to suppress the acid hydrolysis of the sugar chain in the fiber. can. Therefore, it is possible to obtain fine fibrous cellulose having a high axial ratio.

The heat treatment time is preferably 1 second or more and 300 minutes or less, more preferably 1 second or more and 1000 seconds or less, and 10 seconds or more and 800 seconds or less after the water is substantially removed from the fiber raw material. Is more preferable. In the present embodiment, the amount of the phosphorus oxo acid group introduced can be within a 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 two or more times, many phosphorus oxo acid groups can be introduced into the fiber raw material. In the present embodiment, as an example of a preferable embodiment, there is a case where the phosphorus oxo acid group introduction step is performed twice.

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

<Alkaline treatment process>
In the case of producing fine fibrous cellulose, the phosphoric acid group-introduced fiber may be treated with an alkali between the phosphorus oxo acid group-introducing step and the defibration treatment step described later. The method of the alkaline treatment is not particularly limited, and examples thereof include a method of immersing the phosphorus oxo acid group-introduced fiber in an alkaline 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, it is preferable to use, for example, sodium hydroxide or potassium hydroxide as the alkaline 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, a polar organic solvent exemplified by alcohol, and the like, 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 immersion time of 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 is preferably 100% by mass or more and 100,000% by mass or less, and 1000% by mass or more and 10,000% by mass or less, for example, with respect to the absolute 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 alkaline treatment step, the phosphoric acid group-introduced fiber may be washed with water or an organic solvent after the phosphoric acid group introduction step and before the alkaline treatment step. After the alkali treatment step and before the defibration treatment step, it is preferable to wash the alkali-treated phosphoroxoic acid group-introduced fibers with water or an organic solvent from the viewpoint of improving handleability.

<Acid treatment process>
In the case of producing fine fibrous cellulose, an acid treatment may be performed on the phosphoric acid group-introduced fiber between the step of introducing the phosphoric 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 the acid treatment is not particularly limited, and examples thereof include a method of immersing the fiber raw material in an acidic liquid containing an acid. The concentration of the acidic liquid used is not particularly limited, but is preferably, for example, 10% by mass or less, and more preferably 5% by mass or less. The pH of the acidic solution used is not particularly limited, but is 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 solution, 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, chloric 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, and 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, and 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 100,000% by mass or less, and 1000% by mass or more and 10,000% by mass or less, for example, with respect to the absolute dry mass of the fiber raw material. Is more preferable.

<Defibration treatment>
Fine fibrous cellulose can be obtained by defibrating the phosphorus oxo acid group-introduced fiber in the defibration treatment step. In the defibration treatment step, for example, a defibration treatment apparatus can be used. The defibration processing device is not particularly limited, but for example, a high-speed defibrator, a grinder (stone mill type crusher), a high-pressure homogenizer or an ultra-high pressure homogenizer, a high-pressure collision type crusher, a ball mill, a bead mill, a disc type refiner, a conical refiner, and a twin shaft. A kneader, a vibration mill, a homomixer under high speed rotation, an ultrasonic disperser, or a beater can be used. Among the above-mentioned defibration processing devices, it is more preferable to use a high-speed defibrator, a high-pressure homogenizer, and an ultra-high-pressure homogenizer, which are less affected by crushed media and have less risk of contamination.

In the defibration treatment step, for example, it is preferable to dilute the phosphorus oxo acid group-introduced fiber with a dispersion medium to form a slurry. As the dispersion medium, one or more selected from water and an organic solvent such as a polar organic solvent can be used. The polar organic solvent is not particularly limited, but for example, alcohols, polyhydric alcohols, ketones, ethers, esters, aprotic polar solvents and the like are preferable. Examples of alcohols include methanol, ethanol, isopropanol, n-butanol, isobutyl alcohol and the like. Examples of polyhydric alcohols include ethylene glycol, propylene glycol and glycerin. Examples of the ketone include acetone, methyl ethyl ketone (MEK) and the like. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monon-butyl ether, propylene glycol monomethyl ether and the like. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the aprotonic 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 appropriately set. Further, the slurry obtained by dispersing the phosphorus oxo acid group-introduced fiber in a dispersion medium may contain a solid content other than the phosphorus oxo acid group-introduced fiber such as urea having a hydrogen bond property.

(Multivalent metal)
The fibrous cellulose-containing material of the present invention contains a polyvalent metal. In the present specification, a multivalent metal is a metal having a divalent value or higher. The multivalent metal contained in the fibrous cellulose-containing material may be a polyvalent metal ion. Since the phosphorus oxo acid group is an anionic group, at least a part of the polyvalent metal ion may form an ionic bond by electrostatic interaction with the phosphorus oxo acid group. In addition, liberated polyvalent metal elements and polyvalent metal ions may be present in the fibrous cellulose-containing material.

The polyvalent metal is derived from a component added as a metal salt in the agglutination step of the manufacturing process of the fibrous cellulose-containing material described later. Since such a metal salt has a function of aggregating fine fibrous cellulose, it can also be called an aggregating agent. Examples of metal salts containing polyvalent metals include aluminum sulfate (sulfate band), aluminum chloride, polyaluminum chloride, calcium chloride, magnesium chloride, calcium sulfate, magnesium sulfate, copper chloride, copper sulfate, iron chloride, iron sulfate, and the like. Examples include lead chloride and lead sulfide. As the metal salt containing a divalent or higher metal component, only one of the above salts may be added, or two or more of the above salts may be added. Among them, as the metal salt containing a divalent or higher valent metal component, it is preferable to use at least one selected from aluminum sulfate (aluminum band), aluminum chloride, polyaluminum chloride, calcium chloride and calcium sulfate, and aluminum chloride and It is more preferable to use at least one selected from calcium chloride.

(Optional ingredient)
The fibrous cellulose-containing material of the present invention may further contain an optional component. Examples of the optional component include defoaming agents, lubricants, ultraviolet absorbers, dyes, pigments, stabilizers, surfactants, preservatives and the like. Further, the fibrous cellulose-containing material may contain a hydrophilic polymer, a hydrophilic low molecule, an organic ion or the like as optional components.

The hydrophilic polymer is preferably a hydrophilic oxygen-containing organic compound (excluding the above-mentioned cellulose fibers), and examples of the oxygen-containing organic compound include polyethylene glycol, polyethylene oxide, casein, dextrin, starch, and modification. Distillate, polyvinyl alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol, etc.), polyvinylpyrrolidone, polyvinylmethyl ether, polyacrylic acid salts, acrylic acid alkyl ester copolymer, urethane-based copolymer, cellulose derivative (hydroxyethyl cellulose, carboxy) Ethyl cellulose, carboxymethyl cellulose, etc.) and the like.

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

Examples of the organic ion include tetraalkylammonium ion and tetraalkylphosphonium ion. 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, cetyltrimethylammonium ion, stearyltrimethylammonium ion, octyldimethylethylammonium ion, lauryldimethylethylammonium ion, didecyldimethylammonium ion, lauryldimethylbenzylammonium ion and tributylbenzylammonium ion. Examples of the tetraalkylphosphonium ion include tetramethylphosphonium ion, tetraethylphosphonium ion, tetrapropylphosphonium ion, tetrabutylphosphonium ion, and lauryltrimethylphosphonium ion. Further, examples of the tetrapropyl onium ion and the tetrabutyl onium ion include tetra n-propyl onium ion and tetra n-butyl onium ion, respectively.

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

(Manufacturing method of fibrous cellulose-containing material)
The step of producing the fibrous cellulose-containing material includes a step of adding a polyvalent metal salt to the fine fibrous cellulose-containing slurry. Specifically, the polyvalent metal salt as described above is added to the fine fibrous cellulose-containing slurry obtained in the above-mentioned defibration treatment step. At this time, it is preferable to add the polyvalent metal salt as an aqueous solution containing the polyvalent metal salt.

The step of adding the polyvalent metal salt is also called an agglomeration step because the fine fibrous cellulose is agglomerated by the metal component. In the agglomeration step, it is preferable to add a metal salt containing a polyvalent metal in an amount of 1 part by mass or more to 100 parts by mass of the fine fibrous cellulose contained in the dispersion liquid, so that the amount is 5 parts by mass or more. It is more preferable to add to. Further, it is preferable to add a metal salt containing a polyvalent metal to 100 parts by mass or less of the fine fibrous cellulose contained in the dispersion liquid so as to be 100 parts by mass or less, and to add 50 parts by mass or less. It is more preferable to do so.

The agglomeration step preferably further includes a filtration step after adding a polyvalent metal salt and stirring. By providing such a filtration step, a concentrate can be obtained. The filter medium used in the filtration step is not particularly limited, but a filter medium made of stainless steel, filter paper, polypropylene, nylon, polyethylene, polyester or the like can be used. Polypropylene filter media are preferred because acids may be used. The lower the air permeability of the filter medium, the higher the yield. Therefore, the yield is 30 cm ³ / cm ² · sec or less, more preferably 10 cm ³ / cm ² · sec or less, and further preferably 1 cm ³ / cm ² · sec or less.

The filtration step may further include a compression step. A squeezing device can also be used in the compression step. As such a device, a general press device such as a belt press, a screw press, or a filter press can be used, and the device is not particularly limited. The pressure at the time of compression is preferably 0.2 MPa or more, and more preferably 0.4 MPa or more.

The filtration step may be followed by an acid addition step. In the method for producing a fibrous cellulose-containing material, a polyvalent metal component is added to a dispersion liquid containing fine fibrous cellulose, and then an acid is added to remove at least a part of the divalent or higher metal component. The acid component added in the acid addition step may be either an inorganic acid or an organic acid. Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and the like. Examples of the organic acid include malic acid, acetic acid, citric acid, malic acid, lactic acid, adipic acid, sebacic acid, stearic acid, maleic acid, succinic acid, tartrate acid, fumaric acid, gluconic acid and the like. Above all, it is preferable to add at least one selected from sulfuric acid and hydrochloric acid. The concentration of the acid component (acidic liquid) used is not particularly limited, but is preferably 5N or less, and more preferably 1N or less. By setting the concentration of the acidic liquid in the above range, deterioration due to decomposition of cellulose can be suppressed. At least a part of the above acids may remain in the fibrous cellulose-containing material.

It is preferable that a filtration step is further provided after the acid addition step. By providing such a filtration step, a concentrate can be efficiently obtained. Further, the filtration step may include a compression step.

The method for producing the fibrous cellulose-containing material may further include a powdering step after the acid addition step. When the method for producing the fibrous cellulose-containing material includes a powdering step, methods such as mixer pulverization, spray drying, oven drying, and dehydration with an organic solvent can be adopted. These methods can also be combined as appropriate. The obtained fibrous cellulose-containing material may be in the form of powders or granules, or may be in the form of flocs, flakes, or pastes.

(Liquid composition containing fibrous cellulose)
The present invention also relates to a fibrous cellulose-containing liquid composition (hereinafter, also simply referred to as a liquid composition) formed by mixing the above-mentioned fibrous cellulose-containing material and a 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.

The type of the solvent is not particularly limited, and examples thereof include water, an organic solvent, and a mixture of water and an organic solvent. Examples of the organic solvent include alcohols, polyhydric alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc) and the like. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, t-butyl alcohol and the like. Examples of polyhydric alcohols include ethylene glycol and glycerin. Examples of the ketone include acetone, methyl ethyl ketone and the like. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, ethylene glycol mono t-butyl ether and the like.

The redispersion of the fine fibrous cellulose-containing material can be carried out by a conventional method. For example, a step of adding the above-mentioned solvent to a fine fibrous cellulose-containing material to prepare a liquid containing the fine fibrous cellulose-containing material, and a step of dispersing the fine fibrous cellulose in the liquid containing the fine fibrous cellulose-containing material. Redispersion can be performed by the step of causing. As the dispersant used in the step of dispersing the fine fibrous cellulose in the liquid containing the fine fibrous cellulose-containing substance, the same disperser as the defibration treatment device described in the above <defibration treatment> may be used. ..

The solid content concentration in the liquid composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and more preferably 1% by mass or more, based on the total mass of the liquid composition. Is even more preferable. The solid content concentration in the liquid composition is preferably 90% by mass or less, more preferably 50% by mass or less, based on the total mass of the liquid composition.

When the solid content concentration in the fibrous cellulose-containing liquid composition is 0.5% by mass or less and the total light transmittance is 95% or more when measured under the condition of an optical path length of 1 cm in accordance with JIS K 7361. Is preferable, 98% or more is more preferable, and 99% or more is further preferable. As described above, the liquid composition of the present invention is excellent in transparency. As the haze meter used for measuring the total light transmittance, HM-150 manufactured by Murakami Color Technology Research Institute can be used. When measuring the total light transmittance, a glass cell for liquid having an optical path length of 1 cm is used, and the zero point measurement is performed with ion-exchanged water contained in the glass cell.

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, and examples thereof include thermoplastic resins and thermosetting resins. Examples of the resin include acrylic resin, polycarbonate resin, polyester resin, polyamide resin, silicone resin, fluororesin, chlorine resin, epoxy resin, melamine resin, phenol resin, polyurethane resin, and the like. Examples thereof include diallyl phthalate-based resins, alcohol-based resins, and precursors of these resins. Above all, the resin is preferably at least one selected from a fluorine-based resin, a chlorine-based resin, and an acrylic-based resin. The type of resin precursor is not particularly limited, and examples thereof include precursors of thermoplastic resins and thermosetting resins. The precursor of a thermoplastic resin means a monomer or an oligomer having a relatively low molecular weight used for producing a thermoplastic resin. Further, the precursor of a thermosetting resin means a monomer or an oligomer having a relatively low molecular weight that can cause a polymerization reaction or a cross-linking reaction by the action of light, heat, or a curing agent to form a thermosetting resin.

The liquid composition may further contain a water-soluble polymer or a water-soluble low molecule as a resin component in addition to the above-mentioned resin species. Examples of the water-soluble polymer include thickening polysaccharides such as xanthan gum, guar gum, tamarind gum, carrageenan, locust bean gum, quince seed, alginic acid, purulan, carrageenan, and pectin, cationized starch, raw starch, and oxidation. Examples thereof include starches such as starch, etherified starch, esterified starch, and amylose, and metal salts of polyglycerin, hyaluronic acid, and hyaluronic acid. Examples of the water-soluble small molecule include glycerin and diglycerin.

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

(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 molded body is a solid body formed so as to have a desired shape. Examples of the molded product include sheets, beads, filaments and the like. Above all, the molded product is preferably a sheet, beads or filament. When the molded product is bead-shaped, the particle size 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 thickness of the sheet is not particularly limited, but is preferably, for example, 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, for example, with a stylus type thickness gauge (Millitron 1202D manufactured by Marl).

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

The total light transmittance of the sheet is, for example, preferably 85% or more, more preferably 90% or more, still more 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, for example, 100%. Here, the total light transmittance of the sheet is a value measured using, for example, JIS K 7361 and a haze meter (HM-150 manufactured by Murakami Color Technology Research Institute).

The basis weight of the sheet is not particularly limited, ^{but is preferably, for example, 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 according to, for example, JIS P 8124.

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 adjusting the humidity of a 50 mm square sheet for 24 hours under the conditions of 23 ° C. and 50% relative humidity.

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

(Manufacturing method of molded product)
When the molded body is a sheet, the method for producing the sheet includes a coating step of applying a fibrous cellulose-containing substance or a liquid composition on a substrate, or a papermaking step of making a papermaking of the slurry, as described later. Above all, it is preferable that the method for producing the sheet includes a coating step of coating the fibrous cellulose-containing material or the liquid composition on the substrate.

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

The material of the base material used in the coating process is not particularly limited, but a material having a high wettability to a fibrous cellulose-containing material or a liquid composition (slurry) can suppress shrinkage of the sheet during drying. Although good, it is preferable to select a sheet in 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 is not particularly limited. For example, resin films and plates such as polypropylene, acrylic, polyethylene terephthalate, vinyl chloride, polystyrene, polycarbonate, and polyvinylidene chloride, metal films and plates of aluminum, zinc, copper, and iron plates, and their surfaces are oxidized. , Stainless film or plate, brass film or plate, etc. can be used.

In the coating process, if the viscosity of the slurry is low and it develops on the base material, a dammed frame is fixed on the base material to obtain a sheet with a predetermined thickness and basis weight. You may. The frame for damming is not particularly limited, but it is preferable to select, for example, a frame in which the end portion of the sheet adhering after drying can be easily peeled off. From this point of view, a resin plate or a metal plate molded is more preferable. In the present embodiment, for example, a resin plate such as a polypropylene plate, an acrylic plate, a polyethylene terephthalate plate, a vinyl chloride plate, a polystyrene plate, a polycarbonate plate, a polyvinylidene chloride plate, or a metal plate such as an aluminum plate, a zinc plate, a copper plate, or an iron plate. , And those whose surfaces are oxidized, stainless steel plates, brass plates and the like can be used. The coating machine for coating the slurry on the substrate is not particularly limited, and for example, 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 atmospheric temperature when the slurry is applied to the substrate are not particularly limited, but are preferably, for example, 5 ° C. or higher and 80 ° C. or lower, more preferably 10 ° C. or higher and 60 ° C. or lower, and 15 ° C. It is more preferably 50 ° C. or higher, and particularly preferably 20 ° C. or higher and 40 ° C. or lower. When the coating temperature is equal to or higher than the above lower limit, the slurry can be coated more easily. When the coating temperature is not more than the above upper limit, the volatilization of the dispersion medium during coating can be suppressed.

In the coating process, the slurry is based so that the finished basis weight of the sheet is preferably 10 g / m ² or more and 200 g / m ² or less, and more preferably 20 g / m ² or more and 180 g / m ^{2 or less.} It is preferable to apply it to 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 substrate. 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, and for example, a method of heating and drying with hot air, infrared rays, far infrared rays or near infrared rays (heat drying method) or a method of vacuum drying (vacuum drying method) is applied. can do. Although the heat drying method and the vacuum drying method may be combined, 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 by using, for example, an infrared device, a far infrared device or a near infrared device.

The heating temperature in the heat-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 equal to or higher than the above lower limit, the dispersion medium can be rapidly volatilized. Further, when the heating temperature is not more than the above upper limit value, it is possible to suppress the cost required for heating and suppress the discoloration of the fibrous cellulose due to heat.

<Papermaking process>
The papermaking process is performed by making a slurry with a paper machine. The paper machine used in the paper making process is not particularly limited, and examples thereof include continuous paper machines such as a long net type, a circular net type, and an inclined type, and a multi-layer paper making machine combining these. In the papermaking process, a known papermaking method such as hand-making may be adopted.

The papermaking process is performed by filtering and dehydrating the slurry with a wire to obtain a wet paper sheet, and then pressing and drying the 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 for example, a sheet made of an organic polymer, a woven fabric, or a porous membrane is 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 porous membrane of polytetrafluoroethylene having a pore size of 0.1 μm or more and 20 μm or less, polyethylene terephthalate having a pore size of 0.1 μm or more and 20 μm or less, a polyethylene woven fabric, or the like can be mentioned.

In the sheeting step, a method for producing a sheet from a slurry is, for example, a water-squeezed section in which a slurry containing fibrous cellulose is discharged onto the upper surface of an endless belt and a dispersion medium is squeezed from the discharged slurry to generate a web. It can be done using a manufacturing apparatus with a drying section that dries the web to produce a sheet. An endless belt is disposed from the watering section to the drying section, and the web generated in the watering section is conveyed to the drying section while being placed on the endless belt.

The dehydration method used in the papermaking process is not particularly limited, and examples thereof include a dehydration method normally used in the production of paper. Among these, a method of dehydrating with a long net, a circular net, an inclined wire, or the like and then further dehydrating with a roll press is preferable. The drying method used in the papermaking process is not particularly limited, and examples thereof include methods used in the production of paper. 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 can be used as a thickener or a particle dispersion stabilizer. By mixing the fine fibrous cellulose of the present invention with a 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 also be preferably used for mixing with an organic solvent containing a resin component. By mixing the fine fibrous cellulose of the present invention with an organic solvent containing a resin component, a resin composite in which the fine fibrous cellulose is uniformly dispersed can be formed. Similarly, a fine fibrous cellulose redispersion slurry can be used to form a film and used as various films.

Further, the fibrous cellulose-containing material of the present invention can be used, for example, as a reinforcing agent or an additive in cement, paints, inks, lubricants and the like. In addition, the molded product obtained by applying the fibrous cellulose-containing material on the base material 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, and a transportation device. It is also suitable for applications such as members of the above, electronic devices, and electrochemical elements.

Hereinafter, the features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the specific examples shown below.

<Manufacturing example 1>
[Manufacturing of fine fibrous cellulose dispersion A]
As raw material pulp, Oji Paper's softwood kraft pulp (solid content 93% by mass, basis weight 208 g / m ² sheet form, Canadian standard drainage degree (CSF) measured according to JIS P 8121 by separation is 700 ml) It was used.

The 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 (absolute dry mass) of the raw material pulp, and 33 parts by mass of phosphorous acid (phosphonic acid), 120 parts by mass of urea, and 150 parts of water. It was prepared to be parts by mass, and a chemical-impregnated pulp was obtained. Next, the obtained chemical-impregnated pulp was heated in a hot air dryer at 165 ° C. for 250 seconds to introduce a phosphorus oxo acid group into the cellulose in the pulp to obtain phosphorus oxo oxide pulp 1.

Then, the obtained phosphorus oxo oxide pulp 1 was washed. In the washing treatment, the pulp dispersion obtained by pouring 10 L of ion-exchanged water into 100 g (absolutely dry mass) of phosphoroxo oxide pulp is stirred so that the pulp is uniformly dispersed, and then filtration and dehydration are repeated. I went by that. When the electrical conductivity of the filtrate became 100 μS / cm or less, the washing end point was set.

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

The infrared absorption spectrum of the phosphorus oxo oxide pulp 1 thus obtained was measured using FT-IR. As a result, ^{absorption based on P = O of the phosphonic acid group, which is a metamorphic form of the phosphite group, was observed around 1210 cm -1} , and the phosphonic acid group (phosphonic acid group) was added to the pulp. Was confirmed.

Further, when the obtained phosphoric oxide pulp 1 was tested and analyzed by an X-ray diffractometer, two positions were found: 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less. A typical peak was confirmed in, and it was confirmed that it had cellulose type I crystals.

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

By X-ray diffraction, it was confirmed that the obtained fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. The amount of the first dissociated acid measured by the measuring method described later was 1.51 mmol / g. The total amount of dissociated acid was 1.55 mmol / g.

<Manufacturing example 2>
[Manufacturing of fine fibrous cellulose dispersion B]
Linoxo oxide pulp 2 and fine fibrous cellulose dispersion B were obtained in the same manner as in Production Example 1 except that the chemical-impregnated pulp was heated in a hot air dryer at 165 ° C. for 200 seconds.

The infrared absorption spectrum of the phosphorus oxo oxide pulp 1 thus obtained was measured using FT-IR. As a result, ^{absorption based on P = O of the phosphonic acid group, which is a metamorphic form of the phosphite group, was observed around 1210 cm -1} , and the phosphonic acid group (phosphonic acid group) was added to the pulp. Was confirmed.

By X-ray diffraction, it was confirmed that the obtained fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. The amount of the first dissociated acid measured by the measuring method described later was 1.20 mmol / g. The total amount of dissociated acid was 1.22 mmol / g.

<Manufacturing example 3>
[Manufacturing of fine fibrous cellulose dispersion C]
The operation was the same as in Production Example 1 except that 45 parts by mass of ammonium dihydrogen phosphate was used instead of 33 parts by mass of phosphorous acid (phosphonic acid) and the drying time in a hot air dryer at 165 ° C. was set to 200 seconds. , Phosphonic oxide pulp 3 and fine fibrous cellulose dispersion C were obtained.

The infrared absorption spectrum of the phosphorus oxo oxide pulp 3 thus obtained was measured using FT-IR. As a result, absorption ^{of the phosphate group based on P = O was observed around 1230 cm -1} , and it was confirmed that the phosphate group was added to the pulp.

Further, when the obtained phosphoric oxide pulp 3 was tested and analyzed by an X-ray diffractometer, two positions were found: 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less. A typical peak was confirmed in, and it was confirmed that it had cellulose type I crystals.

By X-ray diffraction, it was confirmed that the obtained fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. The amount of the first dissociated acid measured by the measuring method described later was 1.45 mmol / g. The total amount of dissociated acid was 2.45 mmol / g.

<Manufacturing example 4>
[Manufacturing of fine fibrous cellulose dispersion D]
Phosphoric oxide pulp 4 and fine particles were used in the same manner as in Production Example 1 except that 19 parts by mass of phosphoric acid and 16 parts by mass of phosphonic acid (phosphonic acid) were used instead of 33 parts by mass of phosphoric acid (phosphonic acid). A fibrous cellulose dispersion D was obtained.

The infrared absorption spectrum of the phosphorus oxo oxide pulp 4 thus obtained was measured using 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 phosphite group (phosphonic acid group) and a phosphoric acid group were added to.

By X-ray diffraction, it was confirmed that the obtained fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. The amount of the first dissociated acid measured by the measuring method described later was 1.60 mmol / g. The total amount of dissociated acid was 2.25 mmol / g.

<Example 1>
To 500 g of the dispersion liquid A of fine fibrous cellulose, 500 g of a 0.5 mass% calcium chloride aqueous solution was added, stirred for 1 minute, and then filtered. Then, the solid content separated by filtration was squeezed with a filter paper to obtain a concentrate 1 having a solid content concentration of 20% by mass. The concentrate 1 was immersed in 1000 g of a 0.1 N hydrochloric acid aqueous solution for 30 minutes and then filtered. Then, the solid content separated by filtration was squeezed with a filter paper to obtain a concentrate 2 having a solid content concentration of 20% by mass. The concentrate 2 was pulverized using a mixer (Miller 800DG, manufactured by Iwatani Corp.) to obtain a fibrous cellulose-containing material A having a solid content concentration of 20% by mass.

<Example 2>
In Example 1, a fibrous cellulose-containing material B was obtained in the same manner as in Example 1 except that the fine fibrous cellulose dispersion B was used instead of the fine fibrous cellulose dispersion A.

<Example 3>
A fibrous cellulose-containing material C was obtained in the same manner as in Example 1 except that aluminum chloride was used instead of calcium chloride in Example 1.

<Example 4>
In Example 1, a fibrous cellulose-containing material D was obtained in the same manner as in Example 1 except that the fine fibrous cellulose dispersion D was used instead of the fine fibrous cellulose dispersion A.

<Comparative Example 1>
In Example 1, the fibrous cellulose-containing material E was obtained in the same manner as in Example 1 except that the fine fibrous cellulose dispersion C was used instead of the fine fibrous cellulose dispersion A.

<Comparative Example 2>
In Comparative Example 1, a fibrous cellulose-containing material F was obtained in the same manner as in Comparative Example 1 except that aluminum chloride was used instead of calcium chloride.

<Evaluation method>
[Measurement of first dissociated acid amount and total dissociated acid amount]
The amount of phosphoxoic acid group of the fine fibrous cellulose is a fibrous form prepared by diluting the fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content is 0.2% by mass. The cellulose-containing slurry was treated with an ion-exchange resin and then titrated with an alkali for measurement.
For the treatment with the ion exchange resin, a strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, conditioned) with a volume of 1/10 is added to the above fibrous cellulose-containing slurry, and the mixture is shaken for 1 hour. This was done by pouring onto a mesh with an opening of 90 μm to separate the resin and the slurry.
For titration using alkali, change in pH value indicated by the slurry is measured while adding 10 μl of 0.1 N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry treated with an ion exchange resin every 5 seconds. I went by doing. Titration was performed while blowing nitrogen gas into the slurry from 15 minutes before the start of titration. In this neutralization titration, two points are observed where the increment (differential value of pH with respect to the amount of alkaline drop) becomes maximum in the curve plotting the measured pH with respect to the amount of alkali added. Of these, the maximum point of the increment obtained first when alkali is added 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 is 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. The amount of alkali (mmol) required from the start of titration to the first end point divided by the solid content (g) in the slurry to be titrated was defined as the amount of first dissociating acid (mmol / g). Further, the 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 amount of dissociated acid (mmol / g).

[Analysis of multivalent metal content]
10 g of the fibrous cellulose-containing material obtained in Examples and Comparative Examples was taken, heated at 525 ° C. for incineration, dissolved in 5 mL of 1% nitric acid, and wet-decomposed. After filtering this solution with a 0.45 μm filter, ultrapure water was added and the volume was adjusted to 50 mL, and ICP-AES measurement was performed. The polyvalent metal content (mmol / g) in the fibrous cellulose-containing material is the polyvalent metal content (mmol) obtained by ICP-AES measurement, and the solid content (g) of the fibrous cellulose-containing material tested. Calculated by dividing by.

[Evaluation of redispersibility]
The fibrous cellulose-containing substances obtained in Examples and Comparative Examples were added to ion-exchanged water to obtain 100 g of a slurry having a solid content concentration of 0.5% by mass. The obtained slurry was stirred with a magnetic stirrer for 5 minutes, and then 1N sodium hydroxide was added dropwise with the same stirring to adjust the pH of the slurry to 10. This slurry was stirred with a disperser (TK Robomix manufactured by Primix Corporation) at 1500 rpm (2.5 m / s) for 5 minutes. After 24 hours, the slurry was diluted with ion-exchanged water so that the solid content concentration became 0.2% by mass, and the slurry was stirred with a disperser at 1500 rpm (2.5 m / s) for 5 minutes. The obtained slurry was placed in a glass screw bottle having a capacity of 50 mL and stirred at 2200 rpm for 2 minutes with a rotation / revolution type super mixer (ARE-250 manufactured by Shinky Co., Ltd.) to perform defoaming treatment. After allowing to stand for 24 hours in an environment of 23 ° C., the total light transmittance was measured using a haze meter (HM-150 manufactured by Murakami Color Technology Research Institute) in accordance with JIS K 7361. At the time of measurement, the slurry was placed in a glass cell for liquid (manufactured by Fujiwara Seisakusho, MG-40, backlight path) having an optical path length of 1 cm, and the measurement was performed. The zero point measurement was performed with ion-exchanged water contained in the same glass cell.

In the fibrous cellulose-containing material obtained in the examples, the residual amount of the metal component was reduced.

Claims (8)

A fibrous cellulose-containing product having a fiber width of 1000 nm or less and containing a phospholic acid group or a fibrous cellulose having a substituent derived from a phosphoxoic acid group and a polyvalent metal.
Wherein the first dissociation acid amount in the fibrous cellulose and A1, when the total dissociated acid amount in the fibrous cellulose was A2, Ri der value of A1 / A2 is 0.65 or more,
A fibrous cellulose-containing material having a polyvalent metal content of 0.070 mmol / g or less. A fibrous cellulose-containing product having a fiber width of 1000 nm or less and containing a phosphite group or a fibrous cellulose having a substituent derived from a phosphite group and a polyvalent metal .
A fibrous cellulose-containing material having a polyvalent metal content of 0.070 mmol / g or less . The fibrous cellulose-containing material according to claim 1 or 2, wherein the total light transmittance measured under the following measurement condition (a) is 95% or more;
Measurement method (a):
Ion-exchanged water is added to the fibrous cellulose-containing material to prepare an aqueous suspension A having a solid content concentration of 0.5% by mass; the pH of the aqueous suspension A is adjusted to 10 and then 2.5 m / sec. Add ion-exchanged water to the obtained water suspension to make the solid content concentration 0.2% by mass, allow it to stand for 24 hours, and then, according to JIS K 7361, have an optical path length of 1 cm. Measure the total light transmittance under the conditions. The fibrous cellulose-containing material according to any one of claims 1 to 3, wherein the content of the fibrous cellulose is 5% by mass or more with respect to the total mass of the fibrous cellulose-containing material. The fibrous cellulose-containing product according to any one of claims 1 to 4, which is in a solid state. A fibrous cellulose-containing liquid composition obtained by mixing the fibrous cellulose-containing material according to any one of claims 1 to 5 with a solvent. When the solid content concentration in the fibrous cellulose-containing liquid composition is 0.5% by mass or less and the total light transmittance is 95% or more when measured under the condition of an optical path length of 1 cm in accordance with JIS K 7361. The fibrous cellulose-containing liquid composition according to claim 6. A molded product 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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