WO2020050347A1

WO2020050347A1 - Solid body and method for manufacturing solid body

Info

Publication number: WO2020050347A1
Application number: PCT/JP2019/034905
Authority: WO
Inventors: 孟晨趙; 雄右轟; 裕一野口
Original assignee: 王子ホールディングス株式会社
Priority date: 2018-09-06
Filing date: 2019-09-05
Publication date: 2020-03-12
Also published as: JPWO2020050347A1

Abstract

The present invention addresses the problem of providing a solid body in which the water absorption rate and yellowness are low. The present invention relates to a solid body containing fibrous cellulose that measures 1000 nm or less in fiber width and has a phosphoric acid group or a substituent derived from a phosphoric acid group, and an organic onium ion as a counterion of the phosphoric acid group or substituent derived from a phosphoric acid group, wherein the organic onium ion fulfills at least one condition selected from (a) and (b) below: (a) contains a hydrocarbon group having at least five carbons (b) has at least 17 carbons in total.

Description

Solid body and method for producing solid body

The present invention relates to a solid body and a method for producing the solid body.

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

Generally, since fine fibrous cellulose is stably dispersed in an aqueous solvent, it is provided in the form of an aqueous dispersion and is often used for various purposes. On the other hand, when a composite or the like is produced by mixing fine fibrous cellulose with a resin, there is a demand that the fine fibrous cellulose be mixed with an organic solvent and used. As a technique to meet such a demand, a technique for producing a fine fibrous cellulose-containing dispersion in which fine fibrous cellulose is dispersed in a dispersion medium containing an organic solvent has been studied.

For example, Patent Document 1 discloses a fine fibrous cellulose composite in which a surfactant is adsorbed to fine fibrous cellulose having a carboxy group. Here, after the cellulose fibers are refined in an aqueous solvent, a method of agglomerating and dispersing the fine fibrous cellulose in an organic solvent or a method of obtaining fine fibrous cellulose by refining the cellulose fibers in an organic solvent is used. It has been disclosed. Further, Patent Document 2 discloses a process of preparing an aqueous dispersion of fine fibrous cellulose having a carboxylate type group, and converting the carboxylate type group to a carboxylic acid amine salt type of an amine having an organic group. Disclosed is a method for producing a fine fibrous cellulose dispersion, which comprises a step of substituting with a group and a step of dispersing the fine fibrous cellulose having a carboxylic acid amine salt type group in an organic solvent.

JP-A-2011-140738 JP 2012-021081A

溶融 As a method for producing a solid body such as a molded body from fine fibrous cellulose, a melt kneading method and a casting method are known. In addition, as a method for producing a solid containing fine fibrous cellulose, a method of obtaining a solid by injecting an aqueous dispersion into a large amount of an organic solvent is also known. However, when the fine fibrous cellulose as described above is used, the water absorption and yellowness of the solid body may be increased.

Therefore, in order to solve such problems of the prior art, the present inventors have studied to provide a solid having a low water absorption and a low yellowness.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a fibrous cellulose having a phosphate group or a substituent derived from a phosphate group, It has been found that by containing an organic onium ion having a predetermined structure as a counter ion of a substituent derived from a group, a solid having low water absorption and low yellowness can be obtained.
Specifically, the present invention has the following configuration.

[1] A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphate group or a substituent derived from a phosphate group, and containing an organic onium ion as a counter ion of the phosphate group or the substituent derived from the phosphate group. A solid body,
The organic onium ion is a solid that satisfies at least one condition selected from the following (a) and (b):
(A) containing a hydrocarbon group having 5 or more carbon atoms;
(B) The total number of carbon atoms is 17 or more.
[2] The solid according to [1], wherein the organic onium ion is an organic ammonium ion.
[3] The solid according to [1] or [2], wherein the amount of the phosphate group or the amount of the substituent derived from the phosphate group in the fibrous cellulose is 0.50 mmol / g or more.
[4] The solid according to any one of [1] to [3], wherein the solid content concentration is 80% by mass or more.
[5] The solid body according to any one of [1] to [4], which is a molded body.
[6] The solid according to any one of [1] to [5], which is a sheet.
[7] The solid according to any one of [1] to [6], further comprising a resin.
[8] A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphate group or a phosphate group-derived substituent, an organic onium ion as a counter ion of the phosphate group or the phosphate group-derived substituent, Contacting a composition comprising water and a first solvent with a second solvent having a hydrogen bond term (δh) of Hansen solubility parameter of 12.0 MPa ^1/2 or more,
A method for producing a solid, wherein the organic onium ion satisfies at least one condition selected from the following (a) and (b):
(A) containing a hydrocarbon group having 5 or more carbon atoms;
(B) The total number of carbon atoms is 17 or more.

According to the present invention, a solid having low water absorption and low yellowness can be provided.

FIG. 1 is a graph showing the relationship between the amount of NaOH added to fibrous cellulose having a phosphate group and the electrical conductivity. FIG. 2 is a graph showing the relationship between the amount of NaOH added to fibrous cellulose having a carboxy group and the electrical conductivity.

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

(Solid body)
The present invention relates to a solid body containing fibrous cellulose having a fiber width of 1000 nm or less. Specifically, the present invention provides a fibrous cellulose having a fiber width of 1,000 nm or less and having a phosphate group or a phosphate group-derived substituent, and a counter ion of the phosphate group or the phosphate group-derived substituent. The present invention relates to a solid containing organic onium ions. Here, the organic onium ion satisfies at least one condition selected from the following (a) and (b).
(A) It contains a hydrocarbon group having 5 or more carbon atoms.
(B) The total number of carbon atoms is 17 or more.

Since the solid body of the present invention has the above configuration, the water absorption and the yellowness are suppressed to a low level. The water absorption of the solid is a value measured by the following method. First, the solid body is conditioned at 23 ° C. and a relative humidity of 50% for 24 hours, and the conditioned weight is measured. Next, the solid body after measuring the humidity control weight is immersed in ion-exchanged water for 24 hours, and excess water remaining on the surface is wiped off, and then the wet weight is measured. Then, the water absorption (%) of the solid body is calculated from the humidity control weight and the wet weight according to the following equation.
Water absorption (%) = 100 × (wet weight-humidified weight) / humidified weight

水 The water absorption of the solid body is preferably 200% or less, more preferably 100% or less, and even more preferably 70% or less. The lower limit of the water absorption of the solid body may be 0%. Thus, the water absorption of the solid body of the present invention is kept low. The water resistance of the solid body can be increased by setting the water absorption of the solid body within the above range. Further, by setting the water absorption of the solid body within the above range, the surface smoothness of the solid body can be more effectively improved.

In the present specification, the yellowness of the solid body is a yellowness measured according to ASTM E313 of the pellet produced under the following condition a.
(Condition a)
After pulverizing the solid into a powder, the powder is press-molded at a surface pressure of 600 MPa for 1 minute so that the basis weight becomes 3000 g / m ² to obtain a pellet for measuring yellowness.
The pellets produced in this way under the condition a are used as the pellets for measuring the yellowness. The yellowness of the yellowness measurement pellet is measured by reflected light measurement according to ASTM E313. The yellowness is measured using a spectrophotometer. As such a measuring device, for example, a spectrophotometer manufactured by Spectroeye; Gretag Macbeth can be used.

The yellowness (YI ₀ ) of the solid body measured according to ASTM E313 is preferably 30 or less, more preferably 27 or less, and even more preferably 25 or less. The lower limit of the yellowness (YI ₀ ) of the solid is not particularly limited, but is preferably, for example, 0.1 or more. Thus, the yellowness of the solid body of the present invention is kept low. The surface smoothness of the solid body can be more effectively improved by setting the yellowness of the solid body within the above range.

When the solid body is in the form of a sheet, it is preferable that the yellowness (YI ₁₀₀ ) of the sheet in terms of the film thickness of 100 μm calculated by the following equation b is 32 or less.
(Equation b)
Sheet yellowness (YI ₁₀₀ ) in terms of film thickness 100 μm = sheet yellowness (YI) × 100 (μm) / sheet film thickness (μm)
However, in the above formula b, the yellowness (YI ₁₀₀ ) of the sheet is the yellowness of the sheet measured by transmitted light measurement according to JIS K 7373. As a device for measuring the yellowness (YI) of the sheet, for example, Color Cut i manufactured by Suga Test Instruments Co., Ltd. can be mentioned.

The yellowness (YI ₁₀₀ ) of the sheet is preferably 32 or less, more preferably 28 or less, and even more preferably 24 or less. The lower limit (YI ₁₀₀ ) of the yellowness of the sheet is not particularly limited, but is preferably, for example, 0.1 or more.

The present invention relates to fibrous cellulose having a fiber width of 1000 nm or less and having a phosphate group or a phosphate-derived substituent, and an organic onium ion as a counter ion of the phosphate group or the phosphate-derived substituent. It may be related to a solid body consisting of In the present invention, the fine fibrous cellulose has a phosphate group or a substituent derived from a phosphate group, and contains an organic onium ion having a predetermined structure, so that the solid body contains a hydrophobic resin or the like. Even in the absence, a low water absorption and a low yellowness are achieved.

形態 The form of the solid body of the present invention is not particularly limited, and is preferably, for example, sheet-like, powder-like, or thread-like. The solid body may be a gel body. Among them, the solid body is preferably in the form of a sheet, beads (granules), or filaments (filaments), and particularly preferably in the form of sheets. When the solid body is in the form of beads, the particle diameter of the beads is preferably 0.1 mm or more and 10 mm or less. When the solid body is 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.

The solid content concentration of the solid body is preferably 80% by mass or more, more preferably 84% by mass or more, even more preferably 88% by mass or more based on the total mass of the solid body. . In addition, the solid content concentration of the solid body may be 100% by mass.

The solid body may contain water, and when the solid body contains water, the water content is preferably 20% by mass or less based on the total mass of the solid body, and is preferably 15% by mass or less. %, More preferably 10% by mass or less. The water content in the solid body can be measured by placing 200 mg of the solid body on a moisture meter (MS-70, manufactured by A & D Corporation) and heating at 140 ° C. The water content in the solid body can be calculated from the measured water content.

固形 The solid body of the present invention is preferably a molded body. In the present specification, a molded body is a solid body molded into a desired shape. Examples of the molded body include sheets, beads, and filaments. Among them, the molded article is preferably a sheet, beads or filament, and particularly preferably a sheet.

(Fibrous cellulose)
The solid body of the present invention contains fibrous cellulose having a fiber width of 1,000 nm or less and having a phosphate group or a substituent derived from a phosphate group. The fiber width of the fibrous cellulose having a phosphate group or a substituent derived from a phosphate group is preferably 100 nm or less, more preferably 8 nm or less. The fiber width of the fibrous cellulose can be measured by, for example, observation with an electron microscope. In addition, in this specification, fibrous cellulose having a fiber width of 1000 nm or less may be referred to as fine fibrous cellulose.

繊維 The fiber width of fibrous cellulose can be measured by, for example, observation with an electron microscope. The average fiber width of the fibrous cellulose is, for example, 1000 nm or less. The average fiber width of the fibrous cellulose is, for example, preferably from 2 nm to 1000 nm, more preferably from 2 nm to 100 nm, further preferably from 2 nm to 50 nm, and more preferably from 2 nm to 10 nm. Particularly preferred. By setting the average fiber width of the fibrous cellulose to 2 nm or more, dissolution in water as cellulose molecules is suppressed, and the effect of improving the strength, rigidity, and dimensional stability of the fibrous cellulose can be more easily exhibited. it can. The fibrous cellulose is, for example, a monofibrous cellulose.

The average fiber width of the fibrous cellulose is measured, for example, using an electron microscope as follows. First, an aqueous suspension of fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less was prepared, and this suspension was cast on a carbon film-coated grid that had been subjected to a hydrophilization treatment, and a TEM observation sample was prepared. And In the case of including a wide fiber, an SEM image of a surface cast on glass may be observed. Next, observation with an electron microscope image is performed at a magnification of 1,000 times, 5000 times, 10,000 times, or 50,000 times depending on the width of the fiber to be observed. However, the sample, observation conditions and magnification are adjusted so as to satisfy the following conditions.
(1) One straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y perpendicular to the straight line is drawn in the same image, and 20 or more fibers intersect the straight line Y.
The width of the fiber that intersects the straight line X and the straight line Y is visually read for an observation image satisfying the above conditions. In this way, at least three or more sets of observation images of the surface portions that do not overlap each other are obtained. Next, the width of the fiber that intersects the straight line X and the straight line Y is read for each image. Thereby, the fiber width of at least 20 fibers × 2 × 3 = 120 fibers is read. Then, the average value of the read fiber width is defined as the average fiber width of the fibrous cellulose.

The fiber length of the fibrous cellulose is not particularly limited, but is preferably, for example, 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, destruction of the crystalline region of fibrous cellulose can be suppressed. Further, the slurry viscosity of the fibrous cellulose can be set in an appropriate range. The fiber length of the fibrous cellulose can be determined by, for example, image analysis using TEM, SEM, or AFM.

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

軸 The axial ratio (fiber length / fiber width) of the fibrous cellulose is not particularly limited, but is preferably, for example, 20 or more and 10,000 or less, and more preferably 50 or more and 1000 or less. When the axial ratio is equal to or more than the lower limit, a sheet containing fine fibrous cellulose is easily formed. It is preferable that the axial ratio be equal to or less than the above upper limit, for example, when handling fibrous cellulose as an aqueous dispersion, handling such as dilution becomes easy.

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

Fibrous cellulose has a phosphate group or a substituent derived from a phosphate group (sometimes simply referred to as a phosphate group). The phosphate group has, for example, a larger number of anionic groups per molecule than a carboxy group or the like, and thus may have more organic onium ions as counterions. Thereby, it is considered that the water absorption and the yellowness of the solid body can be more effectively increased.

The phosphate group or a substituent derived from a phosphate group is, for example, a substituent represented by the following formula (1), and is generalized as a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid.
The phosphate group is a divalent functional group corresponding to, for example, phosphoric acid obtained by removing a hydroxy group. Specifically, it is a group represented by —PO ₃ H ₂ . The substituent derived from the phosphate group includes substituents such as a salt of the phosphate group and a phosphate group. The substituent derived from the phosphate group may be contained in the fibrous cellulose as a group in which the phosphate group is condensed (for example, a pyrophosphate group). Further, the phosphate group may be, for example, a phosphite group (phosphonate group), and the substituent derived from the phosphate group may be a salt of a phosphite group, a phosphite ester group, or the like. Is also good.

In the formula (1), a, b and n are natural numbers (where a = b × m). Of α ¹ , α ² ,..., α ⁿ and α ′, a is O ⁻ , and the rest are either R or OR. Note that all of αn and α ′ may be O ⁻ . R represents a hydrogen atom, a saturated-straight hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-straight hydrocarbon group, or an unsaturated-branched hydrocarbon group, respectively. A hydrogen group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or a derivative thereof. At least a part of β ^{b +} is an organic onium ion described later.

Examples of the saturated-linear hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, but are not particularly limited. Examples of the saturated-branched hydrocarbon group include an i-propyl group and a t-butyl group, but are not particularly limited. Examples of the saturated-cyclic hydrocarbon group include a cyclopentyl group and a cyclohexyl group, but are not particularly limited. Examples of the unsaturated-linear hydrocarbon group include a vinyl group and an allyl group, but are not particularly limited. Examples of the unsaturated-branched hydrocarbon group include an i-propenyl group and a 3-butenyl group, but are not particularly limited. Examples of the unsaturated-cyclic hydrocarbon group include a cyclopentenyl group and a cyclohexenyl group, but are not particularly limited. Examples of the aromatic group include a phenyl group and a naphthyl group, but are not particularly limited.

Further, as the deriving group for 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 to a main chain or a side chain of the above various hydrocarbon groups. Although a group is mentioned, it is not particularly limited. Further, the number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R to the above range, the molecular weight of the phosphate group can be adjusted to an appropriate range, facilitating penetration into the fiber material, and increasing the yield of fine cellulose fibers. You can also.

β ^{b +} is a monovalent or higher cation composed of an organic or inorganic substance. Examples of the monovalent or higher cation composed of an organic substance include aliphatic ammonium and aromatic ammonium, and at least a part of β ^{b +} is an organic onium ion described later. Examples of the monovalent or higher cation composed of an inorganic substance include ions of alkali metals such as sodium, potassium, and lithium, and cations of divalent metals such as calcium and magnesium, and hydrogen ions. There is no particular limitation. These can be applied alone or in combination of two or more. The monovalent or higher cation composed of an organic or inorganic substance is preferably, but not particularly limited to, sodium or potassium ions that are less likely to yellow when a β-containing fiber material is heated and are easily industrially used.

The amount of the phosphate group or the substituent derived from the phosphate group (the amount of the phosphate group) introduced into the fibrous cellulose is preferably, for example, 0.10 mmol / g or more per 1 g (mass) of the fibrous cellulose, and 0.20 mmol / g. / G or more, more preferably 0.50 mmol / g or more, and particularly preferably 1.00 mmol / g or more. The amount of phosphate groups introduced into fibrous cellulose is, for example, preferably 5.20 mmol / g or less, more preferably 3.65 mmol / g or less, per 1 g (mass) of fibrous cellulose. More preferably, it is not more than 00 mmol / g. Here, the unit mmol / g indicates the amount of the substituent per 1 g of the mass of fibrous cellulose when the counter ion of the phosphate group is a hydrogen ion (H ⁺ ). By setting the amount of the phosphoric acid group to be in the above range, the fineness of the fiber raw material can be facilitated, and the stability of the fibrous cellulose can be increased. Further, by setting the amount of the phosphate group to be in the above range, the content of organic onium ions that can be included in the fibrous cellulose can be adjusted to an appropriate range, whereby the dispersion of the fibrous cellulose in the organic solvent can be performed. Sex can be effectively improved.

導入 The amount of phosphate groups introduced into fibrous cellulose can be measured, for example, by conductivity titration. In the measurement by the conductivity titration method, the amount of introduction is measured by determining the change in conductivity while adding an alkali such as an aqueous sodium hydroxide solution to the obtained slurry containing fibrous cellulose.

FIG. 1 is a graph showing the relationship between the amount of NaOH added to fibrous cellulose having a phosphate group and the electrical conductivity. The amount of phosphate groups introduced into fibrous cellulose is measured, for example, as follows. First, a slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, before the treatment with the strongly acidic ion exchange resin, a fibrillation treatment similar to the fibrillation treatment step described later may be performed on the measurement target. Next, a change in electric conductivity is observed while adding an aqueous solution of sodium hydroxide, and a titration curve as shown in FIG. 1 is obtained. As shown in FIG. 1, the electrical conductivity sharply decreases at first (hereinafter, referred to as “first region”). Thereafter, the conductivity starts to slightly increase (hereinafter, referred to as “second region”). Thereafter, the increment of the conductivity increases (hereinafter, referred to as “third region”). Note that the boundary point between the second region and the third region is defined as the point at which the amount of change in the conductivity twice (ie, the increment (slope) of the conductivity) becomes maximum. Thus, three regions appear in the titration curve. Of these, the amount of alkali required in the first region is equal to the amount of strongly acidic groups in the slurry used for titration, and the amount of alkali required in the second region is equal to the amount of weakly acidic groups in the slurry used for titration. Become equal. When the phosphate group causes condensation, the weakly acidic group is apparently lost, and the amount of alkali required in the second region is smaller than the amount of alkali required in the first region. On the other hand, the amount of the strongly acidic group matches the amount of the phosphorus atom regardless of the presence or absence of condensation. For this reason, simply referring to the phosphate group introduction amount (or phosphate group amount) or the substituent group introduction amount (or substituent amount) indicates a strongly acidic group amount. Therefore, the value obtained by dividing the alkali amount (mmol) required in the first region of the titration curve obtained above by the solid content (g) in the slurry to be titrated is the phosphate group introduction amount (mmol / mmol). g).

In the measurement of the amount of the substituent by the titration method, if the titration interval of the aqueous sodium hydroxide solution is too short, the amount of the substituent may be lower than it should be. It is desirable to titrate the aqueous sodium solution by 50 μL every 30 seconds.

<Manufacturing process of fine fibrous cellulose>
<Textile raw materials>
Fine fibrous cellulose is produced from a fiber raw material containing cellulose. The fiber material containing cellulose is not particularly limited, but pulp is preferably used because it is easily available and inexpensive. Pulp includes, for example, wood pulp, non-wood pulp, and deinked pulp. Examples of the wood pulp include, but are not particularly limited to, hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), and unbleached kraft pulp (UKP). And oxygen bleached kraft pulp (OKP); semi-chemical pulp such as semi-chemical pulp (SCP) and chemical ground wood pulp (CGP); groundwood pulp (GP); and thermomechanical pulp (TMP, BCTMP). And mechanical pulp. Non-wood pulp includes, but is not limited to, cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as hemp, straw and bagasse. Examples of the deinked pulp include, but are not particularly limited to, deinked pulp made from waste paper. As the pulp of this embodiment, one of the above-mentioned types may be used alone, or two or more types may be used in combination.
Among the above pulp, for example, wood pulp and deinked pulp are preferable from the viewpoint of availability. In addition, among wood pulp, a viewpoint that the cellulose ratio is large and the yield of fine fibrous cellulose at the time of defibration treatment is high, and the decomposition of cellulose in pulp is small, and fine fibrous cellulose of long fibers having a large axial ratio can be obtained. From the viewpoint, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are more preferable. In addition, when fine fibrous cellulose of long fibers having a large axial ratio is used, the viscosity tends to increase.

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

<Phosphate group introduction step>
The step of producing fine fibrous cellulose includes a step of introducing a phosphate group. In the phosphate group introduction step, at least one compound selected from compounds capable of introducing a phosphate group by reacting with a hydroxyl group of a cellulose-containing fiber material (hereinafter, also referred to as “compound A”) is converted into cellulose. This is a step of acting on a fiber raw material containing. By this step, a phosphate group-introduced fiber is obtained.

In the phosphate group introduction step according to the present embodiment, the reaction between the fiber material containing cellulose and the compound A is performed in the presence of at least one selected from urea and its derivatives (hereinafter, also referred to as “compound B”). You may. On the other hand, the reaction between the fiber raw material containing cellulose and the compound A may be performed in a state where the compound B is not present.

例 As an example of a method of causing compound A to act on a fiber raw material in the presence of compound B, a method of mixing compound A and compound B with a dry, wet, or slurry fiber raw material may be mentioned. Among them, it is preferable to use a fiber material in a dry state or a wet state, and particularly to use a fiber material in a dry state, because of high uniformity of the reaction. The form of the fiber raw material is not particularly limited, but is preferably, for example, cotton or a thin sheet. The compound A and the compound B may be added to the fiber material in the form of a powder, a solution dissolved in a solvent, or a state in which the compound A and the compound B are heated to a melting point or higher and melted. Among these, it is preferable to add in the form of a solution dissolved in a solvent, particularly in the form of an aqueous solution, because of high reaction uniformity. Further, the compound A and the compound B may be added simultaneously to the fiber raw material, may be added separately, or may be added as a mixture. The method of adding the compound A and the compound B is not particularly limited, but when the compound A and the compound B are in a solution state, the fiber raw material may be immersed in the solution, absorbed and then taken out. May be added dropwise to the solution. In addition, the necessary amount of compound A and compound B may be added to the fiber raw material, or the excessive amount of compound A and compound B may be added to the fiber raw material, respectively, and then the excess compound A and compound B may be squeezed or filtered. It may be removed.

Examples of the compound A used in the present embodiment include a compound having a phosphorus atom and capable of forming an ester bond with cellulose, and specifically, phosphoric acid or a salt thereof, phosphorous acid or a salt thereof, dehydration condensation Examples thereof include phosphoric acid or a salt thereof, phosphoric anhydride (diphosphorus pentoxide), and the like, but are not particularly limited. As phosphoric acid, those having various purities can be used. For example, 100% phosphoric acid (normal phosphoric acid) and 85% phosphoric acid can be used. Examples of the phosphorous acid include 99% phosphorous acid (phosphonic acid). The dehydrated condensed phosphoric acid is obtained by condensing two or more molecules of phosphoric acid by a dehydration reaction, and examples thereof include pyrophosphoric acid and polyphosphoric acid. Examples of the phosphate, phosphite, and dehydrated condensed phosphate include phosphoric acid, lithium salt, sodium salt, potassium salt, and ammonium salt of phosphoric acid or dehydrated condensed phosphoric acid. It can be the sum. Among these, phosphoric acid, phosphoric acid, phosphoric acid, from the viewpoint of high efficiency of introduction of the phosphate group, easier to improve the defibration efficiency in the defibration step described later, low cost, and industrially applicable A sodium salt, a potassium salt of phosphoric acid, or an ammonium salt of phosphoric acid is preferable, and phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, or ammonium dihydrogen phosphate is more preferable.

The amount of the compound A added to the fiber raw material is not particularly limited. For example, when the amount of the compound A added is converted into the phosphorus atomic weight, the amount of the 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, further preferably 2% by mass or more and 30% by mass or less. By setting the amount of the 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 amount of phosphorus atoms added to the fiber raw material to be equal to or less than the above upper limit, the effect of improving the yield and the cost can be balanced.

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

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

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

In the phosphoric acid group introduction step, it is preferable to add or mix the compound A or the like to the fiber raw material and then perform a heat treatment on the fiber raw material. As the heat treatment temperature, it is preferable to select a temperature at which a phosphate group can be efficiently introduced while suppressing the thermal decomposition and hydrolysis of the fiber. The heat treatment temperature is, for example, preferably from 50 ° C. to 300 ° C., more preferably from 100 ° C. to 250 ° C., and even more preferably from 130 ° C. to 200 ° C. In addition, equipment having various heat media can be used for the heat treatment, for example, a stirring drying apparatus, a rotary drying apparatus, a disk drying apparatus, a roll heating apparatus, a plate heating apparatus, a fluidized bed drying apparatus, an air current A drying device, a reduced-pressure drying device, an infrared heating device, a far-infrared heating device, and a microwave heating device can be used.

In the heat treatment according to the present embodiment, for example, the compound A is added to a thin sheet-form fiber material by impregnation or the like, and then the fiber material and the compound A are heated while kneading or stirring with a kneader or the like. Can be adopted. Thereby, it becomes possible to suppress the concentration unevenness of the compound A in the fiber raw material and more uniformly introduce the phosphate group to the surface of the cellulose fiber contained in the fiber raw material. This is because when the water molecules move to the fiber material surface with drying, the dissolved compound A is attracted to the water molecules by the surface tension and moves to the fiber material surface similarly (that is, the concentration unevenness of the compound A decreases). It can be considered that this is caused by the fact that it can be suppressed.

In addition, the heating device used for the heat treatment always generates, for example, the water retained by the slurry and the water generated by the dehydration condensation (phosphate esterification) reaction between compound A and the hydroxyl group contained in cellulose or the like in the fiber material. It is preferable that the device can be discharged outside the device system. As such a heating device, for example, an air-blowing oven or the like can be mentioned. By constantly discharging the water in the system, it is possible to suppress the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the phosphorylation, and also to suppress the acid hydrolysis of the sugar chains in the fiber. it can. For this reason, it becomes possible to obtain fine fibrous cellulose having a high axial ratio.

The time of the heat treatment is, for example, preferably from 1 second to 300 minutes after water is substantially removed from the fiber raw material, more preferably from 1 second to 1000 seconds, and more preferably from 10 seconds to 800 seconds. Is more preferable. In the present embodiment, by setting the heating temperature and the heating time in an appropriate range, the amount of the phosphate group introduced can be set in a preferable range.

The phosphate group introduction step may be performed at least once, but may be repeated twice or more. By performing the phosphate group introduction step twice or more, a large number of phosphate groups can be introduced into the fiber raw material. In the present embodiment, as an example of a preferred embodiment, a case where the phosphate group introduction step is performed twice is exemplified.

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

<Alkali treatment step>
In the case of producing fine fibrous cellulose, the fiber raw material may be subjected to an alkali treatment between the phosphate group introduction step and the defibration treatment step described below. The method of the alkali treatment is not particularly limited, and includes, for example, a method of immersing the phosphate group-introduced fiber in an alkaline solution.

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

温度 The temperature of the alkali solution in the alkali treatment step is not particularly limited, but is preferably, for example, 5 ° C or more and 80 ° C or less, more preferably 10 ° C or more and 60 ° C or less. The immersion time of the phosphate group-introduced fiber in the alkali solution in the alkali treatment step is not particularly limited, but is preferably, for example, 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 alkali solution used in the alkali treatment is not particularly limited. For example, it is preferably from 100% by mass to 100,000% by mass, and preferably from 1,000% by mass to 10,000% by mass, based on the absolute dry mass of the phosphate group-introduced fiber. Is more preferable.

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

<Acid treatment step>
In the case of producing fine fibrous cellulose, an acid treatment may be performed on the fiber raw material between the step of introducing a phosphate group and the defibration treatment step described below. For example, a phosphoric acid group introduction step, an acid treatment, an alkali treatment, and a fibrillation 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 acid-containing acid solution. 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 liquid used is not particularly limited, but is preferably, for example, 0 or more and 4 or less, and more preferably 1 or more and 3 or less. As the acid contained in the acidic liquid, for example, an inorganic acid, a sulfonic acid, a carboxylic acid and the like can be used. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, phosphoric acid, boric acid and the like. Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and the like. Examples of the carboxylic acid include formic acid, acetic acid, citric acid, gluconic acid, lactic acid, oxalic acid, 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, for example, 5 ° C or more and 100 ° C or less, and more preferably 20 ° C or more and 90 ° C or less. The immersion time in the acid solution in the acid treatment is not particularly limited, but is preferably, for example, 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, for example, 100% by mass to 100,000% by mass, and more preferably 1,000% by mass to 10,000% by mass, based on the absolute dry mass of the fiber raw material. Is more preferred.

<Fibrillation processing>
By subjecting the phosphate group-introduced fibers to defibration in the defibration step, fine fibrous cellulose is obtained. In the defibrating process, for example, a defibrating device can be used. The defibrating apparatus is not particularly limited, but includes, for example, a high-speed defibrating machine, 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 refiner, a conical refiner, and a twin-screw. A kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, a beater, or the like can be used. Among the above defibration apparatuses, it is more preferable to use a high-speed defibrator, a high-pressure homogenizer, or an ultra-high-pressure homogenizer, which is less affected by the pulverized media and is less likely to cause contamination.

In the fibrillation treatment step, for example, it is preferable to dilute the phosphate group-introduced fiber with a dispersion medium to form a slurry. As the dispersion medium, one or more kinds 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 the alcohols include methanol, ethanol, isopropanol, n-butanol, isobutyl alcohol and the like. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin and the like. Examples of ketones include acetone and methyl ethyl ketone (MEK). Examples of the ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and propylene glycol monomethyl ether. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the aprotic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP) and the like.

固形 The solid content concentration of the fine fibrous cellulose during the defibration treatment can be set as appropriate. In addition, the slurry obtained by dispersing the phosphate group-introduced fibers in a dispersion medium may contain a solid content other than the phosphate group-introduced fibers such as urea having hydrogen bonding properties.

(Organic onium ion)
The solid of the present invention contains an organic onium ion as a counter ion of a phosphate group or a substituent derived from a phosphate group of fibrous cellulose. In the present invention, at least a part of the organic onium ion is present as a counter ion of fibrous cellulose, but a free organic onium ion may be present in the solid. Note that the organic onium ion does not form a covalent bond with the fibrous cellulose.

The organic onium ion satisfies at least one condition selected from the following (a) and (b).
(A) It contains a hydrocarbon group having 5 or more carbon atoms.
(B) The total number of carbon atoms is 17 or more.
That is, the fibrous cellulose has at least one selected from an organic onium ion having a hydrocarbon group having 5 or more carbon atoms and an organic onium ion having a total carbon number of 17 or more, and is derived from a phosphate group or a phosphate group. Includes as a counter ion of the substituent. When the organic onium ion satisfies at least one condition selected from the above (a) and (b), the dispersibility of fibrous cellulose in an organic solvent can be more effectively increased.

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

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

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

Such organic onium ions include, for example, lauryl trimethyl ammonium, cetyl trimethyl ammonium, stearyl trimethyl ammonium, octyl dimethyl ethyl ammonium, lauryl dimethyl ethyl ammonium, didecyl dimethyl ammonium, lauryl dimethyl benzyl ammonium, tributyl benzyl ammonium, methyl tri-n -Octyl ammonium, hexyl ammonium, n-octyl ammonium, dodecyl ammonium, tetradecyl ammonium, hexadecyl ammonium, stearyl ammonium, N, N-dimethyldodecyl ammonium, N, N-dimethyltetradecyl ammonium, N, N-dimethylhexadecyl Ammonium, N, N-dimethyl-n-octadecylammonium , Dihexylammonium, di (2-ethylhexyl) ammonium, di-n-octylammonium, didecylammonium, didodecylammonium, didedecylmethylammonium, N, N-didodecylmethylammonium, polyoxyethylenedodecylammonium, alkyldimethylbenzylammonium , Di-n-alkyldimethylammonium, behenyltrimethylammonium, tetraphenylphosphonium, tetraoctylphosphonium, acetonyltriphenylphosphonium, allyltriphenylphosphonium, amyltriphenylphosphonium, benzyltriphenylphosphonium, ethyltriphenylphosphonium, diphenylpropylphosphonium , Triphenylphosphonium, tricyclohexylphosphonium And tri -n- octyl phosphonium like. The alkyl group in alkyldimethylbenzylammonium and di-n-alkyldimethylammonium includes a straight-chain alkyl group having 8 to 18 carbon atoms.

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

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

分子 The molecular weight of the organic onium ion is preferably 2000 or less, more preferably 1800 or less. By setting the molecular weight of the organic onium ion within the above range, the handleability of fibrous cellulose can be improved. Further, by setting the molecular weight of the organic onium ion within the above range, it is possible to suppress a decrease in the content of fibrous cellulose in the solid body.

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

Further, the content of the organic onium ion in the solid body is preferably 0.5 to 2 times the molar amount of the phosphate group contained in the fibrous cellulose, but is not particularly limited. . The content of the organic onium ion can be measured by tracking atoms typically contained in the organic onium ion. Specifically, the nitrogen atom is measured when the organic onium ion is an ammonium ion, and the phosphorus atom is measured when the organic onium ion is a phosphonium ion. When the fibrous cellulose contains a nitrogen atom or a phosphorus atom in addition to the organic onium ion, a method of extracting only the organic onium ion, for example, performing an extraction operation with an acid, and then measuring the amount of the target atom Just do it.

As described above, the organic onium ion is preferably an ion exhibiting hydrophobicity. That is, the fibrous cellulose in the present invention exhibits hydrophobicity by having an organic onium ion, and as a result, it becomes easy to lower the water absorption of the solid.

(Optional component)
The solid body of the present invention may further contain a resin. The type of the resin is not particularly limited, and examples thereof include a thermoplastic resin and a thermosetting resin.

Examples of the resin include polyolefin resin, acrylic resin, polycarbonate resin, polyester resin, polyamide resin, silicone resin, fluorine resin, chlorine resin, epoxy resin, melamine resin, phenol resin, and polyurethane resin. Resins, diallyl phthalate resins, alcohol resins, cellulose derivatives, and precursors of these resins can be mentioned. In addition, as a cellulose derivative, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, etc. can be mentioned, for example.

固形 The solid body of the present invention may contain a resin precursor as the resin. The type of the resin precursor is not particularly limited, and examples thereof include a thermoplastic resin and a thermosetting resin precursor. The precursor of the thermoplastic resin means a monomer or an oligomer having a relatively low molecular weight used for producing the thermoplastic resin. In addition, the precursor of the thermosetting resin means a monomer or an oligomer having a relatively low molecular weight that can form a thermosetting resin by causing a polymerization reaction or a cross-linking reaction by the action of light, heat, and a curing agent.

固形 The solid body of the present invention may further contain a water-soluble polymer as a resin in addition to the above-mentioned resin species. Examples of the water-soluble polymer include synthetic water-soluble polymers (eg, carboxyvinyl polymer, polyvinyl alcohol, alkyl methacrylate / acrylic acid copolymer, polyvinylpyrrolidone, sodium polyacrylate, polyethylene glycol, diethylene glycol, triethylene glycol, propylene) Glycol, dipropylene glycol, polypropylene glycol, isoprene glycol, hexylene glycol, 1,3-butylene glycol, polyacrylamide, etc.), thickening polysaccharides (eg, xanthan gum, guar gum, tamarind gum, carrageenan, locust bean gum, quince seed) , Alginic acid, pullulan, carrageenan, pectin, etc.), cationized starch, raw starch, oxidized starch, etherified starch Emissions, esterified starch, starch amylose, etc., glycerol, diglycerol, glycerol such polyglycerin such like, hyaluronic acid, and metal salts of hyaluronic acid.

The content of the resin contained in the solid body is preferably 40% by mass or less, more preferably 30% by mass or less, based on the total mass of the solid matter contained in the solid body. More preferably, it is 20% by mass or less. Further, the content of the resin contained in the solid body may be 1% by mass or more based on the total mass of the solid matter contained in the solid body. The resin does not have to be substantially contained in the solid body. The state in which the resin is not substantially contained means that the content of the resin is less than 1% by mass relative to the total mass of the solid contained in the solid.

The solid body may further contain other optional components. Examples of the optional component include a moisture absorbent. Examples of the moisture absorbent include silica gel, zeolite, alumina, carboxymethyl cellulose, polyvinyl alcohol-soluble cellulose acetate, polyethylene glycol, sepiolite, calcium oxide, diatomaceous earth, activated carbon, activated clay, white carbon, calcium chloride, magnesium chloride, and potassium acetate. , Dibasic sodium phosphate, sodium citrate, water-absorbing polymers and the like.

Further, as optional components, surfactants, organic ions, coupling agents, inorganic layered compounds, inorganic compounds, leveling agents, preservatives, defoamers, organic particles, lubricants, antistatic agents, ultraviolet protection agents, Dyes, pigments, stabilizers, magnetic powders, alignment promoters, plasticizers, dispersants, crosslinking agents, and the like can be given.

The content of the optional components contained in the solid is preferably 40% by mass or less, more preferably 30% by mass or less, based on the total mass of the solids contained in the solid. , 20% by mass or less.

The solid body may contain an organic solvent as an optional component. Although the organic solvent is not particularly limited, for example, methanol, ethanol, n-propyl alcohol, isopropyl alcohol (IPA), 1-butanol, m-cresol, glycerin, acetic acid, pyridine, tetrahydrofuran (THF), acetone , Methyl ethyl ketone (MEK), ethyl acetate, aniline, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), hexane, cyclohexane, benzene, toluene, p-xylene, Examples thereof include diethyl ether chloroform. The content of the organic solvent in the solid is preferably 10% by mass or less, more preferably 5% by mass or less, and more preferably 1% by mass or less, based on the total mass of the solids contained in the solid. % Is more preferable.

(Method for producing solid body)
In the method for producing a solid, a fibrous cellulose having a fiber width of 1000 nm or less and having a phosphate group or a substituent derived from a phosphate group, and an organic counter ion of a phosphate group or a substituent derived from a phosphate group are used. The method preferably includes a step of obtaining a composition containing onium ions and a non-aqueous first solvent, and a step of forming a solid from the composition. Here, the organic onium ion satisfies at least one condition selected from the following (a) and (b).
(A) It contains a hydrocarbon group having 5 or more carbon atoms.
(B) The total number of carbon atoms is 17 or more.

A fibrous cellulose having a fiber width of 1,000 nm or less and having a phosphate group or a substituent derived from a phosphate group; an organic onium ion as a counter ion of the phosphate group or the substituent derived from the phosphate group; The solvent-containing composition is obtained by adding an organic onium ion or a compound capable of forming an organic onium ion by neutralization to a fine fibrous cellulose-containing slurry to obtain a fine fibrous cellulose concentrate; Dispersing the fibrous cellulose concentrate in the non-aqueous first solvent to obtain a composition. In the step of obtaining the fine fibrous cellulose concentrate, the organic onium ion is preferably added as a solution containing the organic onium ion, and more preferably as an aqueous solution containing the organic onium ion.

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

有機 Organic onium ions may be generated only after neutralization with an acid, for example, dodecylamine. In this case, the organic onium ion is obtained by reacting a compound that forms an organic onium ion by neutralization with an acid. In this case, examples of the acid used for neutralization include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, and organic acids such as lactic acid, acetic acid, formic acid, and oxalic acid. In the step of obtaining the concentrate, a compound that forms an organic onium by neutralization may be directly added to the fibrous cellulose-containing slurry, and the phosphate group contained in the fibrous cellulose may be used as a counter ion to form the organic onium ion.

The addition amount of the organic onium ion in the step of obtaining the concentrate is preferably 2% by mass or more, more preferably 10% by mass or more, and more preferably 50% by mass or more based on the total mass of the fibrous cellulose. More preferably, it is particularly preferably 100% by mass or more. In addition, it is preferable that the addition amount of an organic onium ion is 1000 mass% or less with respect to the total mass of fibrous cellulose.
The number of moles of the organic onium ion to be added is preferably at least 0.2 times, more preferably at least 0.5 times the value obtained by multiplying the amount (mole number) of the phosphate group contained in the fibrous cellulose by the valence. Is more preferable, and it is still more preferable that it is 1.0 times or more. The number of moles of the organic onium ion to be added is preferably 10 times or less the value obtained by multiplying the amount (mol number) of the phosphate group contained in the fibrous cellulose by the valence.

When the organic onium ion is added and agitated, aggregates are formed in the fibrous cellulose-containing slurry. This aggregate is an aggregate of fibrous cellulose having an organic onium ion as a counter ion. The fibrous cellulose concentrate can be recovered by filtering the slurry containing the fibrous cellulose in which the aggregates are generated under reduced pressure.

The obtained fibrous cellulose concentrate may be washed with ion-exchanged water. By repeatedly washing the fibrous cellulose concentrate with ion-exchanged water, excess organic onium ions and the like contained in the fibrous cellulose concentrate can be removed.

The ratio of the N atom content to the P atom content (the value of N / P) in the obtained fibrous cellulose concentrate is preferably larger than 1.2, more preferably larger than 2.0. preferable. Further, the ratio of the N atom content to the P atom content (the value of N / P) in the obtained fibrous cellulose concentrate is preferably 5.0 or less. The content of P atoms and the content of N atoms in the fibrous cellulose concentrate can be appropriately calculated by elemental analysis. As the elemental analysis, for example, a trace nitrogen analysis or a molybdenum blue method can be performed after an appropriate pretreatment. When the composition other than the fibrous cellulose concentrate contains P atoms and N atoms, the composition may be separated from the fibrous cellulose concentrate by an appropriate method, followed by elemental analysis.

(4) The solid content concentration of the obtained fibrous cellulose concentrate is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. Further, the solid content concentration of the fibrous cellulose concentrate is preferably 99.5% by mass or less. Note that a step of drying the fibrous cellulose concentrate may be provided so that the solid content concentration of the fibrous cellulose concentrate is in a desired range.

工程 The step of dispersing the obtained fine fibrous cellulose concentrate in the non-aqueous first solvent to obtain a composition is a step of redispersing the fine fibrous cellulose concentrate. Here, the non-aqueous first solvent is preferably a solvent other than water. Specifically, the non-aqueous first solvent is preferably an organic solvent. Examples of such an organic solvent include methanol, ethanol, n-propyl alcohol, isopropyl alcohol (IPA), 1-butanol, and m- Cresol, glycerin, acetic acid, pyridine, tetrahydrofuran (THF), acetone, methyl ethyl ketone (MEK), ethyl acetate, aniline, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF) ), Hexane, cyclohexane, benzene, toluene, p-xylene, diethyl ether chloroform and the like. Further, a mixed solvent obtained by mixing two or more of these organic solvents may be used. Among them, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), methyl ethyl ketone (MEK), toluene and methanol are preferably used.

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

Δp of Hansen solubility parameters of the non-aqueous first solvent (Hansen solubility parameter, HSP value), it is preferably, 10 MPa ^1/2 or more 19 MPa ^1/2 or less is 5 MPa ^1/2 or more 20 MPa ^1/2 or less Is more preferable, and it is more preferable that it is 12 MPa1 ^{/ 2} or more and 18 MPa1 ^{/ 2} or less. Further, .delta.h a hydrogen bond of the HSP value is preferably 5 MPa ^1/2 or more 40 MPa ^1/2 or less, more preferably 5 MPa ^1/2 or more 30 MPa ^1/2 or less, 5 MPa ^1/2 More preferably, it is not less than 20 MPa ^1/2 . It is also preferable that δp is in the range of 0 MPa ^{1/2 to} 4 MPa ^1/2 and δh is in the range of 0 MPa ^{1/2 to} 6 MPa ^1/2 at the same time.

分散 As a dispersing device used for dispersing the fine fibrous cellulose concentrate in the non-aqueous first solvent, for example, the same dispersing device as described in the above-described fibrillation treatment can be used. Alternatively, the fine fibrous cellulose concentrate may be dispersed in an organic solvent by performing ultrasonic treatment.

工程 The step of forming a solid from the composition obtained in the above-described step may be a step of molding the composition using a melt-kneading method or a casting method.

In the step of forming a solid from the composition, the fibrous cellulose having a fiber width of 1,000 nm or less and having a phosphate group or a substituent derived from a phosphate group is substituted with a fibrous cellulose having a phosphate group or a phosphate group. Contacting a composition comprising an organic onium ion as a counter ion of a group and a non-aqueous first solvent with a second solvent having a hydrogen bond term (δh) of Hansen solubility parameter of 12.0 MPa ^1/2 or more. There may be. The method for producing a solid body of the present invention preferably includes a second solvent contacting step, whereby the water absorption and the yellowness of the solid body can be more effectively reduced.

In the second solvent contacting step, the composition obtained in the step of obtaining the composition is brought into contact with a second solvent having a hydrogen bond term (δh) of the Hansen solubility parameter of 12.0 MPa ^1/2 or more. Examples of the second solvent having a hydrogen bond term (δh) of the Hansen solubility parameter of 12.0 MPa ^1/2 or more include, for example, water, methanol, ethanol, n-propyl alcohol, isopropyl alcohol (IPA), 1-butanol, m -Cresol, glycerin, acetic acid and the like. Further, a mixed solvent obtained by mixing two or more of these solvents may be used. Among them, the second solvent is preferably at least one selected from water and methanol, and more preferably water.

The first non-aqueous solvent and the second solvent used in the method for producing a solid are preferably compatible with each other. The difference in the hydrogen bond term (δh) of the Hansen solubility parameter between the nonaqueous first solvent and the second solvent is preferably 15 MPa ^1/2 or more, more preferably 20 MPa ^1/2 or more, and 25 MPa More preferably, it is ^1/2 or more.

The relative permittivity of the second solvent at 25 ° C. is preferably 18 or more, more preferably 30 or more, and further preferably 60 or more. Further, δp of the Hansen solubility parameter (HSP value) of the second solvent is preferably 5 MPa ^1/2 or more and 20 MPa ^1/2 or less, and is preferably 10 MPa ^1/2 or more and 20 MPa ^1/2 or less. Is more preferred. Further, .delta.h a hydrogen bond of the HSP value is preferably 12 MPa ^1/2 or more, more preferably 20 MPa ^1/2 or more, more preferably 40 MPa ^1/2 or more.

The second solvent contacting step is preferably a step of immersing the composition in the second solvent. In this case, the composition may be immersed in the second solvent by injecting or dropping the composition into the second solvent. For example, if the solid body is a filament, it is preferable to include a step of injecting the composition in a thread form into the second solvent, and if the solid body is a bead form, the composition is dropped into the second solvent. It is preferable to include the step of performing. When the solid is in the form of a sheet, the composition may be injected into the second solvent in the form of a sheet, or the sheet precursor formed in the sheet mold may be immersed in the second solvent. When the sheet precursor is immersed in the second solvent, the sheet precursor may be immersed in the second solvent together with the sheet mold.

では In the step of bringing the composition into contact with the second solvent, it is preferable to bring the composition into contact with the second solvent in an amount of at least 40 times the total volume of the composition. That is, it is preferable that the composition be present in a second solvent atmosphere. Further, the second solvent may be exchanged or circulated as necessary.

こと By contacting the composition with the second solvent, the non-aqueous first solvent is removed to form a solid. In the step of producing the solid, it is preferable to include, after the step of bringing the composition into contact with the second solvent, a step of further immersing the solid obtained in the step in the second solvent for a predetermined time or more. In this case, the solid is preferably immersed in the second solvent for 1 hour or more, more preferably for 5 hours or more, and even more preferably for 8 hours or more. The upper limit of the immersion time is not particularly limited, but is preferably, for example, 100 hours or less.

After separating the solid from the second solvent, it is preferable to provide a step of drying the solid. The drying temperature is preferably at least 30 ° C, more preferably at least 40 ° C, even more preferably at least 50 ° C. Further, the drying temperature is preferably 200 ° C. or less. The drying time is preferably 1 minute or more and 100 hours or less. When the solid is separated from the second solvent, the solid may be separated by performing filtration, centrifugation, or the like.

(Fibrous cellulose-containing composition)
The present invention may relate to a fibrous cellulose-containing composition obtained by dispersing the solid obtained through the above-described steps again in an organic solvent. The fibrous cellulose-containing composition may further contain a resin. Since the solid body of the present invention uses fibrous cellulose having excellent compatibility with the organic solvent and the resin, the resin composite formed from the fibrous cellulose-containing composition has excellent strength, Furthermore, it has excellent dimensional stability. In addition, the resin composite formed from the fibrous cellulose-containing composition has excellent transparency.

The resin composite formed from the fibrous cellulose-containing composition may be in the form of a sheet. In this case, the method for forming the sheet includes a step of applying the above-described fibrous cellulose-containing composition onto a substrate. Is preferred. The material of the base material used in the coating step is not particularly limited, but those having high wettability to the composition may be able to suppress shrinkage of the sheet during drying, etc. It is preferable to select one that can be easily peeled off. Above all, a resin film or plate or a metal film or plate is preferable, but not particularly limited. For example, acryl, polyethylene terephthalate, vinyl chloride, polystyrene, polypropylene, polycarbonate, polyvinylidene chloride, etc., resin films and plates, aluminum, zinc, copper, metal films and plates such as iron plates, and those obtained by oxidizing their surfaces A stainless steel film or plate, a brass film or plate, or the like can be used.

In the coating process, if the composition has low viscosity and spreads on the substrate, use a fixed damming frame on the substrate to obtain a sheet of a predetermined thickness and basis weight. May be. The damming frame is not particularly limited. For example, it is preferable to select a frame that can easily peel off the end of the sheet that adheres after drying. From such a viewpoint, a resin plate or a metal plate is more preferable. In the present embodiment, for example, a resin plate such as an acrylic plate, a polyethylene terephthalate plate, a vinyl chloride plate, a polystyrene plate, a polypropylene plate, a polycarbonate plate, a polyvinylidene chloride plate, and a metal plate such as an aluminum plate, a zinc plate, a copper plate, and an iron plate And those obtained by oxidizing the surface thereof, and forming a stainless steel plate, a brass plate, or the like.

塗 A coating machine for coating the composition on the base material 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. Die coaters, curtain coaters, and spray coaters are particularly preferred because the thickness of the coating (sheet) can be made more uniform.

The temperature and the ambient temperature of the liquid composition when applying the composition to the substrate are not particularly limited, but are preferably, for example, 5 ° C or more and 80 ° C or less, more preferably 10 ° C or more and 60 ° C or less. The temperature is more preferably from 15 ° C to 50 ° C, and particularly preferably from 20 ° C to 40 ° C.

In the coating step, the composition is prepared such that the finished basis weight of the sheet is preferably 10 g / m ² or more and 100 g / m ² or less, more preferably 20 g / m ² or more and 60 g / m ² or less. It is preferable to apply to the substrate. By coating so that the grammage is in the above range, a sheet having more excellent strength can be obtained.

The coating step includes a step of drying the composition applied on the substrate. The step of drying the composition is not particularly limited, and is performed, for example, by a non-contact drying method, a method of drying while restraining a sheet, or a combination thereof. The non-contact drying method is not particularly limited. For example, a method of drying by heating with hot air, infrared rays, far infrared rays or near infrared rays (heating drying method), or a method of drying by vacuum (vacuum drying method) is applied. can do. The heat drying method and the vacuum drying method may be combined, but usually, the heat drying method is applied. Drying with infrared, far-infrared, or near-infrared light can be performed using, for example, but not limited to, an infrared device, a far-infrared device, or a near-infrared device. The heating temperature in the heating and drying method is not particularly limited, but is, for example, preferably from 20 ° C to 150 ° C, more preferably from 25 ° C to 105 ° C. When the heating temperature is equal to or higher than the lower limit, the dispersion medium can be quickly volatilized. When the heating temperature is equal to or lower than the upper limit, the cost required for heating and the discoloration of fibrous cellulose due to heat can be suppressed.

(Application)
The use of the solid body of the present invention is not particularly limited, but a reinforcing material, an interior material, an exterior material, a packaging material, an electronic material, an optical material, an acoustic material, a process material, a transport equipment member, an electronic equipment member, It is suitable for applications such as members of electrochemical devices.

場合 When the solid of the present invention is a filament, it can be used for ropes, fishing lines, medical sutures and the like. Further, it can be used as a reinforcing material by being added to resin, rubber, cement and the like. Further, a nonwoven fabric may be formed by randomly laminating filaments. Nonwoven fabrics using filaments are suitable for applications such as filters, battery separators, nets, interior materials, exterior materials, packaging materials, clothing materials, and medical materials. When the solid body of the present invention is a bead, it can be used as an ink, a paint, a molded article, a film, a coating agent, etc. by adding it to a resin or a solvent in addition to an adsorbent and an abrasive.

場合 When the solid body of the present invention is a sheet, it is suitable for use in light-transmitting substrates such as various display devices and various solar cells. In addition, it is also suitable for use as substrates for electronic devices, separators for electrochemical devices, members for home appliances, window materials for various vehicles and buildings, interior materials, exterior materials, packaging materials, and the like. Furthermore, it is also suitable for applications in which the sheet itself is used as a reinforcing material.

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

<Production Example 1>
[Production of fine fibrous cellulose dispersion A]
As a raw material pulp, softwood kraft pulp made by Oji Paper (solid content: 93% by mass, basis weight: 208 g / m ^2, sheet: Disintegrated, Canadian Standard Freeness (CSF) 700 ml measured according to JIS P 8121) It was used.

リン酸 The raw material pulp was phosphorylated as follows. First, a mixed aqueous solution of ammonium dihydrogen phosphate and urea is added to 100 parts by mass (absolute dry mass) of the raw material pulp to obtain 45 parts by mass of ammonium dihydrogen phosphate, 120 parts by mass of urea, and 150 parts by mass of water. To obtain a chemical-impregnated pulp. Next, the obtained chemical-impregnated pulp was heated with a hot air drier at 165 ° C. for 200 seconds to introduce a phosphate group into cellulose in the pulp, thereby obtaining phosphorylated pulp 1.

Next, the obtained phosphorylated pulp 1 was subjected to a washing treatment. In the washing treatment, a pulp dispersion obtained by pouring 10 L of ion-exchanged water into 100 g (absolute dry mass) of the phosphorylated pulp 1 is stirred so that the pulp is uniformly dispersed, and then filtered and dehydrated repeatedly. It was done by doing. When the electric conductivity of the filtrate became 100 μS / cm or less, it was regarded as the washing end point.

リン酸 The phosphorylated pulp 1 after the washing was further subjected to the above-mentioned phosphorylation treatment and the above-mentioned washing treatment once in this order.

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

An infrared absorption spectrum of the phosphorylated pulp 1 thus obtained was measured using FT-IR. As a result, absorption based on a phosphate group was observed at around 1230 cm ⁻¹ , confirming that a phosphate group was added to the pulp.

Further, the obtained phosphorylated pulp 1 was tested and analyzed by an X-ray diffractometer. As a result, two positions of 2θ = around 14 ° to 17 ° and 2θ = around 22 ° to 23 ° were determined. And a typical peak was confirmed, and it was confirmed to have cellulose type I crystals.

イオン Ion-exchanged water was added to the obtained phosphorylated pulp 1 to prepare a slurry having a solid concentration of 2% by mass. This slurry was treated six times at a pressure of 200 MPa with a wet atomizer (manufactured by Sugino Machine Co., Ltd., Starburst) to obtain a fine fibrous cellulose dispersion A containing fine fibrous cellulose.

X-ray diffraction confirmed that the fine fibrous cellulose maintained cellulose type I crystals. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. In addition, the amount of phosphate groups (the amount of strongly acidic groups) measured by a measurement method described later was 2.0 mmol / g.

<Production Example 2>
[Production of fine fibrous cellulose dispersion B]
As a raw material pulp, softwood kraft pulp made by Oji Paper (solid content: 93% by mass, basis weight: 208 g / m ^2, sheet: Disintegrated, Canadian Standard Freeness (CSF) 700 ml measured according to JIS P 8121) It was used. This raw material pulp was subjected to a TEMPO oxidation treatment as follows.

First, the above raw pulp equivalent to 100 parts by mass of dry mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), 10 parts by mass of sodium bromide, 10,000 parts by mass of water Parts. Next, a 13% by mass aqueous solution of sodium hypochlorite was added to 1.0 g of the pulp so as to be 10 mmol, and the reaction was started. During the reaction, a 0.5 M aqueous sodium hydroxide solution was added dropwise to keep the pH at 10 to 10.5, and the reaction was considered to be completed when no change in pH was observed.

Next, the obtained TEMPO oxidized pulp was subjected to a washing treatment. The washing treatment is performed by dehydrating the pulp slurry after TEMPO oxidation, obtaining a dehydrated sheet, pouring 5,000 parts by mass of ion-exchanged water, stirring and uniformly dispersing, and then repeating filtration and dehydration. Was. When the electric conductivity of the filtrate became 100 μS / cm or less, it was regarded as the washing end point.

Further, the obtained TEMPO oxidized pulp was tested and analyzed by an X-ray diffractometer. As a result, it was found that two positions of 2θ = about 14 ° to 17 ° and 2θ = about 22 ° to 23 ° were used. A typical peak was confirmed, and it was confirmed to have cellulose type I crystals.

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

X-ray diffraction confirmed that the fine fibrous cellulose maintained cellulose type I crystals. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. In addition, the amount of carboxy groups measured by the measurement method described later was 1.80 mmol / g.

<Production Example 3>
[Production of fine fibrous cellulose dispersion C]
A phosphorylated pulp 2 was obtained in the same manner as in Production Example 1, except that 33 parts by mass of phosphorous acid (phosphonic acid) was used instead of ammonium dihydrogen phosphate.

Next, the obtained phosphorylated pulp 2 was subjected to a washing treatment. The washing treatment is performed by repeating the operation of pulverizing a pulp dispersion obtained by pouring 10 L of ion-exchanged water into 100 g of phosphorylated pulp (absolute dry mass) so that the pulp is uniformly dispersed, and then filtering and dewatering. went. When the electric conductivity of the filtrate became 100 μS / cm or less, it was regarded as the washing end point.

(5) Next, the phosphorylated pulp 2 after the washing was subjected to a neutralization treatment as follows. First, the phosphorylated pulp slurry having a pH of 12 or more and 13 or less is obtained by diluting the washed phosphorylated pulp 2 with 10 L of ion-exchanged water and then adding a 1N aqueous sodium hydroxide solution little by little with stirring. Was. Next, the phosphorylated pulp slurry was dehydrated to obtain a phosphorylated pulp 2 subjected to a neutralization treatment. Next, the above-described washing treatment was performed on the phosphorylated pulp 2 after the neutralization treatment.

The phosphorylated pulp 2 thus obtained was measured for infrared absorption spectrum using FT-IR. As a result, absorption based on P = O of the phosphonic acid group, which is a tautomer of the phosphite group, was observed at around 1210 cm ⁻¹ , and the phosphite group (phosphonate group) was added to the pulp. Was confirmed.

Further, the obtained phosphorylated pulp 2 was tested and analyzed by an X-ray diffractometer. As a result, two positions, 2θ = around 14 ° to 17 ° and 2θ = around 22 ° to 23 °, were found. And a typical peak was confirmed, and it was confirmed to have cellulose type I crystals.

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

量 The amount of the phosphite group (the amount of the strongly acidic group) of the obtained phosphorylated pulp 2 measured by the measuring method described later was 1.50 mmol / g. The amount of the weak acidic group was 0.13 mmol / g.

<Production Example 4>
[Production of fine fibrous cellulose dispersion D]
A column in which the fine fibrous cellulose dispersion A obtained in Production Example 1 is filled with a strongly acidic ion-exchange resin (Amberjet 1024; conditioned by Organo Co., Ltd.), and a mesh with a mesh size of 90 μm is provided at the tip. Then, the operation of press-fitting with a pump was repeated to convert the counter ion of the phosphate group of the fine fibrous cellulose into hydrogen ion (H ⁺ ). By this operation, an acid-type fine fibrous cellulose dispersion of 2.0% by mass was obtained. After adding 3.10 g of a 55% aqueous solution of tetrabutylammonium hydroxide to 100 g of the obtained acid-type fine fibrous cellulose dispersion, the mixture was stirred for 24 hours with a disperser to obtain a fine fibrous cellulose dispersion D. .

<Example 1>
(Production of fine fibrous cellulose concentrate)
0.60 g of lactic acid was added to 100 g of a 2.43 mass% N, N-didodecylmethylamine aqueous solution to neutralize it in advance, and then added to 100 g of the fine fibrous cellulose dispersion A obtained in Production Example 1. After stirring for 5 minutes, aggregates were formed in the fine fibrous cellulose dispersion. The fine fibrous cellulose dispersion in which the aggregate was generated was filtered under reduced pressure to obtain a fine fibrous cellulose aggregate. The resulting fine fibrous cellulose aggregates were repeatedly washed with ion-exchanged water to remove excess N, N-didodecylmethylamine, lactic acid, and eluted ions contained in the fine fibrous cellulose aggregates. The obtained fine fibrous cellulose aggregate was dried at 30 ° C. and a relative humidity of 40% to obtain a fine fibrous cellulose concentrate.
The counter ion of the phosphate group contained in the fine fibrous cellulose concentrate was N, N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 95% by mass.

(Redispersion of fine fibrous cellulose concentrate)
N-methyl-2-pyrrolidone (NMP) (first solvent) was added to the fine fibrous cellulose concentrate so that the content of fine fibrous cellulose was 2.0% by mass. Thereafter, ultrasonic treatment was performed for 10 minutes using an ultrasonic treatment device (manufactured by Hielscher, UP400S) to obtain a re-dispersed slurry of fine fibrous cellulose.

(Production of fine fibrous cellulose-containing filament)
After filling the re-dispersed slurry of fine fibrous cellulose into a syringe (needle diameter: φ1.5 mm), put 10 g of the filler in a coagulation tank filled with ion-exchanged water (second solvent) at the tip of the needle. / Min into ion-exchanged water to form a fine fibrous cellulose injection in the coagulation bath. After repeating the operation of replacing the ion-exchanged water in the coagulation tank every 30 minutes three times, the fine fibrous cellulose injection product was immersed in the ion-exchanged water for further 12 hours. The fine fibrous cellulose injection product after immersion is taken out of the coagulation bath, dried on a hot plate at 70 ° C. for 30 minutes, then heated to 120 ° C. and further dried for 2 hours to obtain a fine fibrous cellulose-containing filament. Was. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Example 2>
The fine fibrous cellulose dispersion C obtained in Production Example 3 was used in place of the fine fibrous cellulose dispersion A. The procedure of Example 1 was repeated, except that 0.30 g of lactic acid was added to 100 g of an aqueous solution of N, N-didodecylmethylamine at a concentration of 1.20% by mass to neutralize the solution, and then added to the fine fibrous cellulose dispersion C. , A fine fibrous cellulose concentrate, a fine fibrous cellulose re-dispersed slurry, and a fine fibrous cellulose-containing filament were obtained. The counter ion of the phosphate group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecyl ammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 92% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Example 3>
100 g of a 1.83% by mass aqueous solution of polyoxyethylene dodecylamine (the number of oxyethylene residues is 2) was used in place of the aqueous solution of N, N-didodecylmethylamine, and dimethyl sulfoxide (DMSO) was used as the first solvent in N- A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersed slurry, and a fine fibrous cellulose-containing filament were obtained in the same manner as in Example 1 except that methyl-2-pyrrolidone (NMP) was used instead. The counter ion of the phosphate group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecyl ammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 92% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Example 4>
100 g of a 2.33 mass% aqueous solution of alkyldimethylbenzylammonium chloride (alkyl chain having 8 to 18 carbon atoms) was used in place of the aqueous solution of N, N-didodecylmethylamine neutralized with lactic acid, and the first solvent was used. In the same manner as in Example 1 except that methanol was used in place of N-methyl-2-pyrrolidone (NMP), a fine fibrous cellulose concentrate, a fine fibrous cellulose redispersed slurry, and a fine fibrous cellulose-containing filament were used. Obtained. The counter ion of the phosphate group contained in the fine fibrous cellulose concentrate was alkyldimethylbenzylammonium (ADMBA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 84% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Example 5>
100 g of a 3.86% by mass aqueous di-n-alkyldimethylammonium chloride solution (having 16 or 18 carbon atoms in the alkyl chain) was used in place of the aqueous alkyldimethylbenzylammonium chloride solution, and toluene was used as the first solvent. And the fine fibrous cellulose concentrate, the fine fibrous cellulose redispersed slurry, and the fine fibrous cellulose were prepared in the same manner as in Example 4 except that methanol was used instead of ion-exchanged water as the second solvent. A containing filament was obtained. The counter ion of the phosphate group contained in the fine fibrous cellulose concentrate was di-n-alkyldimethylammonium (DADMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 91% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Comparative Example 1>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used in place of the fine fibrous cellulose dispersion A. The same procedure as in Example 1 was carried out except that 0.32 g of lactic acid was added to 100 g of a 1.32% by mass aqueous solution of N, N-didodecylmethylamine to neutralize and then added to the fine fibrous cellulose dispersion B. , A fine fibrous cellulose concentrate, a fine fibrous cellulose re-dispersed slurry, and a fine fibrous cellulose-containing filament were obtained. The counter ion of the carboxy group contained in the fine fibrous cellulose concentrate was N, N-didodecylmethylammonium (DDMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 91% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Comparative Example 2>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used in place of the fine fibrous cellulose dispersion A. The same procedure as in Example 3 was carried out except that 100 g of a 0.99% by mass aqueous solution of polyoxyethylene dodecylamine (the number of oxyethylene residues was 2) pre-neutralized with lactic acid was added to the fine fibrous cellulose dispersion B. , A fine fibrous cellulose concentrate, a fine fibrous cellulose re-dispersed slurry, and a fine fibrous cellulose-containing filament were obtained. The counter ion of the carboxy group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecyl ammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 90% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Comparative Example 3>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used in place of the fine fibrous cellulose dispersion A. A fine fibrous cellulose concentrate, a fine fibrous cellulose re-dispersed slurry, and a fine fibrous cellulose concentrate were prepared in the same manner as in Example 4 except that 100 g of an aqueous 1.27% by mass alkyldimethylbenzylammonium solution was added to the fine fibrous cellulose dispersion B. A fine fibrous cellulose-containing filament was obtained. The counter ion of the carboxy group contained in the fine fibrous cellulose concentrate was alkyldimethylbenzylammonium (ADMBA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 81% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Comparative Example 4>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used in place of the fine fibrous cellulose dispersion A. 2. A fine fibrous cellulose concentrate and a fine fibrous cellulose concentrate were prepared in the same manner as in Example 5 except that 100 g of a 10% by mass aqueous di-n-alkyldimethylammonium chloride solution was added to the fine fibrous cellulose dispersion B. A dispersed slurry and a fine fibrous cellulose-containing filament were obtained. The counter ion of the carboxy group contained in the fine fibrous cellulose concentrate was di-n-alkyldimethylammonium (DADMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 89% by mass. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Comparative Example 5>
The same procedure as in Example 1 was carried out except that the fine fibrous cellulose dispersion A obtained in Production Example 1 was used instead of the fine fibrous cellulose re-dispersed slurry, and ethanol was used instead of ion-exchanged water as the second solvent. Thus, a fine fibrous cellulose-containing filament was obtained. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Comparative Example 6>
Same as Comparative Example 5 except that the fine fibrous cellulose dispersion D obtained in Production Example 4 was used instead of the fine fibrous cellulose dispersion A, and tetrahydrofuran (THF) was used instead of ethanol as the second solvent. Thus, a fine fibrous cellulose-containing filament was obtained. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Comparative Example 7>
A fine fibrous cellulose-containing filament was obtained in the same manner as in Comparative Example 5, except that the fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A. The water absorption and the yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the methods described below.

<Example 6>
After filling the re-dispersed slurry of fine fibrous cellulose obtained in the same manner as in Example 1 into a syringe (needle diameter: φ1.5 mm), it was dropped at 2 g / min into a coagulation tank filled with ion-exchanged water (second solvent). Then, a fine fibrous cellulose injection product was formed in the coagulation bath. After repeating the operation of replacing the ion-exchanged water in the coagulation tank every 30 minutes three times, the fine fibrous cellulose injection product was immersed in the ion-exchanged water for further 12 hours. The fine fibrous cellulose injection product after immersion is taken out of the coagulation bath, dried on a hot plate at 70 ° C. for 30 minutes, then heated to 120 ° C. and further dried for 2 hours to obtain beads containing fine fibrous cellulose. Was. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Example 7>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Example 2 was used in place of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 6 was carried out. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Example 8>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Example 3 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 6 was carried out. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Example 9>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Example 4 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 6 was carried out. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Example 10>
Except that the fine fibrous cellulose redispersed slurry obtained in Example 5 was used instead of the fine fibrous cellulose redispersed slurry obtained in Example 1, and methanol was used as the second solvent instead of ion-exchanged water. In the same manner as in Example 6, fine fibrous cellulose-containing beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Comparative Example 8>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 1 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 6 was carried out. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Comparative Example 9>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 2 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 6 was carried out. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Comparative Example 10>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 3 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 6 was carried out. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Comparative Example 11>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 4 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 5, the same procedure as in Example 10 was carried out. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Comparative Example 12>
Except that the fine fibrous cellulose dispersion A obtained in Production Example 1 was used in place of the fine fibrous cellulose redispersion slurry obtained in Example 1, and ethanol was used instead of ion-exchanged water as the second solvent. In the same manner as in Example 6, fine fibrous cellulose-containing beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Comparative Example 13>
Comparative Example 4 was repeated except that the fine fibrous cellulose dispersion D obtained in Production Example 4 was used instead of the fine fibrous cellulose dispersion A obtained in Production Example 1, and tetrahydrofuran was used as the second solvent instead of ethanol. In the same manner as in Example 12, fine fibrous cellulose-containing beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Comparative Example 14>
Fine fibrous cellulose dispersion containing fine fibrous cellulose was prepared in the same manner as in Comparative Example 12, except that the fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A obtained in Production Example 1. Beads were obtained. The water absorption and the yellowness (YI ₀ ) of the obtained microfibrous cellulose-containing beads were measured and evaluated by the methods described below.

<Example 11>
The re-dispersed slurry of fine fibrous cellulose obtained in the same manner as in Example 1 was dripped into a glass Petri dish so as to have a basis weight of 80 g / m ^2, and was placed in a coagulation tank filled with ion-exchanged water (second solvent) together with the glass Petri dish. It was immersed gently. The operation of exchanging the ion-exchanged water in the coagulation tank every 30 minutes was repeated three times, and then immersed in the ion-exchanged water for further 12 hours, to obtain a hydrous fine fibrous cellulose-containing sheet. The hydrous fine fibrous cellulose was taken out of the coagulation bath, dried on a hot plate at 70 ° C. for 30 minutes, and then heated to 120 ° C. and further dried for 2 hours to obtain a fine fibrous cellulose-containing sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Example 12>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Example 2 was used in place of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 11 was carried out. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Example 13>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Example 3 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 11 was carried out. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Example 14>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Example 4 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 11 was carried out. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Example 15>
Except that the fine fibrous cellulose redispersed slurry obtained in Example 5 was used instead of the fine fibrous cellulose redispersed slurry obtained in Example 1, and methanol was used as the second solvent instead of ion-exchanged water. In the same manner as in Example 11, a fine fibrous cellulose-containing sheet was obtained. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Comparative Example 15>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 1 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the fine fibrous cellulose-containing slurry was contained in the same manner as in Example 11. Beads were obtained. A fine fibrous cellulose-containing sheet was obtained. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Comparative Example 16>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 2 was used in place of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the fine fibrous cellulose-containing slurry was obtained in the same manner as in Example 11. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Comparative Example 17>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 3 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 1, the same procedure as in Example 11 was carried out. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Comparative Example 18>
Except that the fine fibrous cellulose re-dispersed slurry obtained in Comparative Example 4 was used instead of the fine fibrous cellulose re-dispersed slurry obtained in Example 5, the same procedure as in Example 15 was carried out. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Comparative Example 19>
Except that the fine fibrous cellulose dispersion A obtained in Production Example 1 was used instead of the fine fibrous cellulose redispersion slurry obtained in Example 1, the fine fibrous cellulose-containing liquid was added. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Comparative Example 20>
Comparative Example 4 was repeated except that the fine fibrous cellulose dispersion D obtained in Production Example 4 was used instead of the fine fibrous cellulose dispersion A obtained in Production Example 1, and tetrahydrofuran was used as the second solvent instead of ethanol. In the same manner as in Example 19, a fine fibrous cellulose-containing sheet was obtained. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Comparative Example 21>
Fine fibrous cellulose dispersion containing fine fibrous cellulose was prepared in the same manner as in Comparative Example 19 except that the fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A obtained in Production Example 1. I got a sheet. The water absorption, yellowness (YI ₀ ), and yellowness (YI ₁₀₀ ) of the obtained fine fibrous cellulose-containing sheet were measured and evaluated by the methods described below.

<Evaluation>
[Measurement of phosphate group content]
The phosphate group content of the fine fibrous cellulose is a fibrous shape prepared by diluting a fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content becomes 0.2% by mass. After the treatment with the ion exchange resin was performed on the cellulose-containing slurry, the measurement was performed by performing titration using an alkali.
The treatment with the ion-exchange resin is performed by adding 1/10 by volume of a strongly acidic ion-exchange resin (Amberjet 1024; Organo, Inc., conditioned) to the fibrous cellulose-containing slurry and shaking for 1 hour. The resin and the slurry were separated by pouring on a mesh having a mesh size of 90 μm.
In addition, titration using an alkali is performed by adding an aqueous 0.1 N sodium hydroxide solution to a fibrous cellulose-containing slurry after treatment with an ion-exchange resin at a rate of 50 μL once every 30 seconds while maintaining the electrical conductivity of the slurry. The measurement was performed by measuring the change in the value. The amount of phosphoric acid groups (mmol / g) is obtained by dividing the amount of alkali (mmol) required in the region corresponding to the first region shown in FIG. 1 by the solid content (g) in the slurry to be titrated. Was calculated.

(Measurement of carboxy group content)
The carboxy group content of the fine fibrous cellulose is a fibrous cellulose prepared by diluting the fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content becomes 0.2% by mass. The content of the slurry was measured by performing a treatment with an ion-exchange resin and then performing a titration using an alkali.
The treatment with the ion-exchange resin is performed by adding 1/10 by volume of a strongly acidic ion-exchange resin (Amberjet 1024; Organo, Inc., conditioned) to the fibrous cellulose-containing slurry and shaking for 1 hour. The resin and the slurry were separated by pouring on a mesh having a mesh size of 90 μm.
In addition, titration using an alkali is performed by adding 50 μL of a 0.1N aqueous sodium hydroxide solution once every 30 seconds to a fibrous cellulose-containing slurry after treatment with an ion-exchange resin while maintaining the electric conductivity of the slurry. This was done by measuring the change in value. The amount of carboxy groups (mmol / g) is obtained by dividing the amount of alkali (mmol) required in a region corresponding to the first region shown in FIG. 2 in the measurement results by the solid content (g) in the slurry to be titrated. Calculated.

(Measurement of water absorption of solid body)
The solid material (filament, bead, sheet) was conditioned for 24 hours at 23 ° C. and 50% relative humidity, and the conditioned weight was measured. Next, the solid after measuring the humidity control weight was immersed in ion-exchanged water for 24 hours to wipe off excess water remaining on the surface, and then the wet weight was measured. The water absorption (%) of the solid body was calculated from the above moisture control weight and wet weight according to the following equation.
Water absorption (%) = 100 × (wet weight-humidified weight) / humidified weight

[Measurement of Yellowness (YI ₀ ) of Solid State Material]
The solid containing fine fibrous cellulose was pulverized for 5 minutes using a laboratory miller (IFM-800; Iwatani Corporation) to obtain a powder. The obtained powder was press-molded at a surface pressure of 600 MPa for 1 minute using a tableting press (BRE-30; Maekawa Testing Machine Seisakusho) so that the basis weight became 3000 g / m ² , to obtain pellets for measuring yellowness. Was. The yellowness of the obtained pellets was measured using a spectrophotometer (Spectroeye; Gretag Macbeth) in accordance with ASTM E313.

[Calculation of Yellowness YI ₁₀₀ of Sheet]
The yellowness (YI) of the fine fibrous cellulose-containing sheets obtained in Examples 11 to 15 and Comparative Examples 15 to 21 was measured using Color Cut i (manufactured by Suga Test Instruments Co., Ltd.) according to JIS K 7373. It was measured. Next, the yellowness (YI ₁₀₀ ) of the sheet having a thickness of 100 μm was calculated using the following conversion formula.
Sheet yellowness (YI ₁₀₀ ) in terms of film thickness of 100 μm = yellowness of sheet (YI) × (100 (μm)) / (sheet thickness (μm))
The thickness of the sheet was measured using a constant-pressure thickness meter (PG-02; Teklock) in accordance with JIS K6783.

では In the example, a solid having low water absorption and low yellowness was obtained. On the other hand, in Comparative Example, low water absorption and low yellowness were not compatible.

Claims

A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphate group or a substituent derived from a phosphate group, and a solid state containing an organic onium ion as a counter ion of the phosphate group or the substituent derived from the phosphate group. Body
A solid body that satisfies at least one condition selected from the following (a) and (b):
(A) containing a hydrocarbon group having 5 or more carbon atoms;
(B) The total number of carbon atoms is 17 or more.
The solid according to claim 1, wherein the organic onium ion is an organic ammonium ion.
The solid body according to claim 1 or 2, wherein the amount of the phosphate group or the amount of the substituent derived from the phosphate group in the fibrous cellulose is 0.50 mmol / g or more.
(4) The solid according to any one of (1) to (3), wherein the solid content is 80% by mass or more.
固形 The solid body according to any one of claims 1 to 4, which is a molded body.
固形 The solid body according to any one of claims 1 to 5, which is in the form of a sheet.
(7) The solid according to any one of (1) to (6), further comprising a resin.
A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphate group or a phosphate group-derived substituent, an organic onium ion as a counter ion of the phosphate group or the phosphate group-derived substituent, Contacting the composition comprising one solvent with a second solvent having a hydrogen bond term (δh) of the Hansen solubility parameter of 12.0 MPa 1/2 or more,
A method for producing a solid, wherein the organic onium ion satisfies at least one condition selected from the following (a) and (b):
(A) containing a hydrocarbon group having 5 or more carbon atoms;
(B) The total number of carbon atoms is 17 or more.