JPWO2020050347A1 - Solid body and method for producing solid body - Google Patents

Abstract

An object of the present invention is to provide a solid body having a low water absorption rate and a low yellowness. In the present invention, fibrous cellulose having a fiber width of 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group and an organic onium ion as a counter ion of the phosphoric acid group or a substituent derived from the phosphoric acid group. The organic onium ion relates to a solid substance containing at least one of the following conditions (a) and (b). (A) Contains a hydrocarbon group having 5 or more carbon atoms. (B) The total number of carbon atoms is 17 or more.

Description

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

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

In general, 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 producing a complex or the like by mixing fine fibrous cellulose with a resin, there is also a desire to use fine fibrous cellulose mixed with an organic solvent. As a technique for meeting such a demand, a technique for producing a fine fibrous cellulose-containing dispersion liquid in which fine fibrous cellulose is dispersed in a dispersion medium containing an organic solvent has been studied.

For example, Patent Document 1 discloses a fine fibrous cellulose composite in which a surfactant is adsorbed on fine fibrous cellulose having a carboxy group. Here, a method in which the cellulose fibers are finely divided in an aqueous solvent and then the fine fibrous cellulose is aggregated and dispersed in an organic solvent, or a method in which the cellulose fibers are finely divided in an organic solvent to obtain fine fibrous cellulose is used. It is disclosed. Further, Patent Document 2 describes a step of preparing an aqueous dispersion of fine fibrous cellulose having a carboxylate type group, and a carboxylate type group of a carboxylic acid amine salt type of an amine having an organic group. A method for producing a fine fibrous cellulose dispersion liquid, which comprises a step of substituting with a group and a step of dispersing fine fibrous cellulose having a carboxylic acid amine salt type group in an organic solvent is disclosed.

Japanese Unexamined Patent Publication No. 2011-140738 Japanese Unexamined Patent Publication No. 2012-021081

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. Further, as a method for producing a solid body containing fine fibrous cellulose, a method for obtaining a solid body by injecting an aqueous dispersion into a large amount of organic solvent is also known. However, when the fine fibrous cellulose as described above is used, the water absorption rate and the yellowness of the solid body may be increased.

Therefore, in order to solve the problems of the prior art, the present inventors have proceeded with studies for the purpose of providing a solid body having a low water absorption rate and a low yellowness.

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

[1] A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group and an organic onium ion as a counter ion of a phosphoric acid group or a substituent derived from a phosphoric acid group are contained. It is a solid body
The organic onium ion is a solid body that satisfies at least one of the conditions selected from the following (a) and (b);
(A) Contains a hydrocarbon group having 5 or more carbon atoms;
(B) The total number of carbon atoms is 17 or more.
[2] The solid form according to [1], wherein the organic onium ion is an organic ammonium ion.
[3] The solid substance according to [1] or [2], wherein the amount of the phosphate group or the amount of the substituent derived from the phosphoric acid group in the fibrous cellulose is 0.50 mmol / g or more.
[4] The solid substance according to any one of [1] to [3], which has a solid content concentration of 80% by mass or more.
[5] The solid body according to any one of [1] to [4], which is a molded product.
[6] The solid body according to any one of [1] to [5], which is in the form of a sheet.
[7] The solid body according to any one of [1] to [6], which further contains a resin.
[8] A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group, and an organic onium ion as a counter ion of a phosphoric acid group or a substituent derived from a phosphoric acid group, and non-. A step of contacting the composition containing the first aqueous solvent with a second solvent having a hydrogen bond term (δh) of the Hansen solubility parameter of 12.0 MPa ^{1/2 or more is included.}
The organic onium ion is a method for producing a solid body, which satisfies at least one of the conditions selected from the following (a) and (b);
(A) Contains 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, it is possible to provide a solid body having a low water absorption rate and a low yellowness.

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

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical 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, in the present invention, fibrous cellulose having a fiber width of 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group is used as a counter ion of a phosphoric acid group or a substituent derived from a phosphoric acid group. It relates to a solid substance containing an organic onium ion. Here, the organic onium ion satisfies at least one of the conditions selected from the following (a) and (b).
(A) 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-mentioned structure, the water absorption rate and the yellowness are kept low. The water absorption rate of the solid body is a value measured by the following method. First, the solid body is humidity-controlled for 24 hours under the conditions of 23 ° C. and a relative humidity of 50%, and the humidity control weight is measured. Next, the solid body after measuring the humidity control weight is immersed in ion-exchanged water for 24 hours to wipe off excess water remaining on the surface, and then the wet weight is measured. Then, the water absorption rate (%) of the solid body is calculated from the humidity control weight and the wet weight according to the following formula.
Water absorption rate (%) = 100 x (wet weight-humidity control weight) / humidity control weight

The water absorption rate of the solid body is preferably 200% or less, more preferably 100% or less, and further preferably 70% or less. The lower limit of the water absorption rate of the solid body may be 0%. As described above, the water absorption rate of the solid body of the present invention is suppressed to a low level. By setting the water absorption rate of the solid body within the above range, the water resistance of the solid body can be enhanced. Further, by setting the water absorption rate of the solid body within the above range, the surface smoothness of the solid body can be more effectively enhanced.

In the present specification, the yellowness of the solid body is the yellowness measured according to ASTM E313 of the pellet prepared under the following condition a.
(Condition a)
After the solid body is crushed into a powder, the powder is press-molded at a surface pressure of 600 MPa for 1 minute so ^{that the basis weight is 3000 g / m 2, and the pellet is used for measuring yellowness.}
Manufactured under the above condition a The pellet thus obtained becomes a pellet for measuring yellowness. The yellowness of the yellowness measuring pellet is measured by reflected light measurement in accordance with ASTM E313. The yellowness is measured using a spectrophotometer, and as such a measuring device, for example, a spectrophotometer manufactured by Spectroeye; Gretag Macbeth can be used.

_{The yellowness (YI 0} ) measured according to ASTM E313 of the solid body is preferably 30 or less, more preferably 27 or less, and further preferably 25 or less. The lower limit of the yellowness (YI ₀ ) of the solid body is not particularly limited, but is preferably 0.1 or more, for example. As described above, the yellowness of the solid body of the present invention is suppressed to a low level. By setting the yellowness of the solid body within the above range, the surface smoothness of the solid body can be more effectively enhanced.

_{When the solid body is in the form of a sheet, the yellowness (YI 100} ) of the sheet in terms of film thickness of 100 μm calculated by the following formula b is preferably 32 or less.
(Equation b)
_{Sheet yellowness (YI 100} ) converted to film thickness 100 μm = Sheet yellowness (YI) x 100 (μm) / Sheet film thickness (μm)
However, in the above formula b, the yellowness of the sheet (YI ₁₀₀ ) is the yellowness of the sheet measured by transmitted light measurement in accordance with JIS K 7373. Examples of the device for measuring the yellowness (YI) of the sheet include Color Cutei manufactured by Suga Test Instruments Co., Ltd.

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 of the yellowness of the sheet (YI ₁₀₀ ) is not particularly limited, but is preferably 0.1 or more, for example.

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

The form of the solid body of the present invention is not particularly limited, and is preferably sheet-like, powder-granular, thread-like, or the like. The solid body may be a gel-like body. Among them, the solid body is preferably sheet-like, bead-like (powder-granular), filament-like (filament-like), and particularly preferably sheet-like. When the solid body is bead-shaped, the particle size of the beads is preferably 0.1 mm or more and 10 mm or less. When the solid body is in the form of a filament, the width of the filament is preferably 0.1 mm or more and 10 mm or less, and the length of the filament is preferably 1 mm or more and 10000 mm or less.

The solid content concentration of the solid body is preferably 80% by mass or more, more preferably 84% by mass or more, and further preferably 88% by mass or more, based on the total mass of the solid body. .. 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, preferably 15% by mass, based on the total mass of the solid body. It is more preferably% or less, and further 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 Co., Ltd.) and heating at 140 ° C. The water content in the solid body can be calculated from the measured water content.

The solid body of the present invention is preferably a molded body. In the present specification, the molded body is a solid body formed so as to have a desired shape. Examples of the molded product include sheets, beads, filaments and the like. Among them, the molded product 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 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group. The fiber width of the fibrous cellulose having a phosphate group or a substituent derived from a phosphoric acid group is preferably 100 nm or less, and 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 the present specification, fibrous cellulose having a fiber width of 1000 nm or less may be referred to as fine fibrous cellulose.

The fiber width of the fibrous cellulose can be measured, for example, by observation with an electron microscope. The average fiber width of the fibrous cellulose is, for example, 1000 nm or less. The average fiber width of the fibrous cellulose is, for example, 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, further preferably 2 nm or more and 50 nm or less, and 2 nm or more and 10 nm or less. Especially preferable. By setting the average fiber width of the fibrous cellulose to 2 nm or more, it is possible to suppress the dissolution of the fibrous cellulose as a cellulose molecule in water, and to make it easier to exhibit the effects of the fibrous cellulose on improving strength, rigidity and dimensional stability. can. The fibrous cellulose is, for example, monofibrous cellulose.

The average fiber width of fibrous cellulose is measured, for example, using an electron microscope as follows. First, an aqueous suspension of fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less is prepared, and this suspension is cast on a hydrophilized carbon film-coated grid to prepare a sample for TEM observation. And. If it contains wide fibers, an SEM image of the surface cast on the glass may be observed. Next, observation is performed using an electron microscope image at a magnification of 1000 times, 5000 times, 10000 times, or 50,000 times depending on the width of the fiber to be observed. However, the sample, observation conditions and magnification should be adjusted so as to satisfy the following conditions.
(1) A straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y that intersects the straight line perpendicularly is drawn in the same image, and 20 or more fibers intersect the straight line Y.
The width of the fiber intersecting the straight line X and the straight line Y is visually read with respect to the observation image satisfying the above conditions. In this way, at least three sets of observation images of surface portions that do not overlap each other are obtained. Next, for each image, the width of the fiber intersecting the straight line X and the straight line Y is read. As a result, at least 20 fibers × 2 × 3 = 120 fibers are read. Then, the average value of the read fiber widths is taken as the average fiber width of the fibrous cellulose.

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

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

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

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

Fibrous cellulose has a phosphoric acid group or a substituent derived from a phosphoric acid group (sometimes referred to simply as a phosphoric acid group). Since the phosphoric acid group has a larger number of anionic groups per molecule than, for example, a carboxy group, it may have a larger number of organic onium ions as a counter ion. It is considered that this makes it possible to more effectively increase the water absorption rate and the yellowness of the solid body.

The substituent derived from the phosphoric acid group or the phosphoric acid group is, for example, a substituent represented by the following formula (1), and is generalized as a phosphoric acid group or a substituent derived from the phosphoric acid.
The phosphoric acid group is, for example, a divalent functional group obtained by removing a hydroxy group from phosphoric acid. Specifically, it is a group represented by _{−PO 3} H _2. Substituents derived from phosphoric acid groups include substituents such as salts of phosphoric acid groups and phosphoric acid ester groups. The substituent derived from the phosphoric acid group may be contained in the fibrous cellulose as a group in which the phosphoric acid group is condensed (for example, a pyrophosphate group). Further, the phosphoric acid group may be, for example, a phosphite group (phosphonic acid group), and the substituent derived from the phosphoric acid group is a salt of the phosphite group, a phosphite ester group, or the like. May be good.

In formula (1), a, b and n are natural numbers (where a = b × m). ^{α 1, α 2, ···,} a number of alpha ⁿ and alpha 'is O ^- a and the remainder is either R, the OR. It is also possible that all of each αn and α'are O ^−. R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, and an unsaturated-branched chain hydrocarbon, respectively. A hydrogen group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or an inducing group thereof. At ^{least a part of β b +} is an organic onium ion described later.

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

Further, as the inducing group in R, a functional group in which at least one of functional groups such as a carboxy group, a hydroxy group, or an amino group is added or substituted with respect to the main chain or side chain of the above-mentioned various hydrocarbon groups. The group is mentioned, but is not particularly limited. The number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, and more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R to the above range, the molecular weight of the phosphate group can be set to an appropriate range, the penetration into the fiber raw material is facilitated, and the yield of the fine cellulose fiber is increased. You can also do it.

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

The amount of the phosphoric acid group or the substituent derived from the phosphoric acid group introduced (the amount of the phosphoric acid group) in the fibrous cellulose is preferably 0.10 mmol / g or more per 1 g (mass) of the fibrous cellulose, preferably 0.20 mmol. It is more preferably / g or more, further preferably 0.50 mmol / g or more, and particularly preferably 1.00 mmol / g or more. The amount of phosphoric acid group introduced into the fibrous cellulose is, for example, preferably 5.20 mmol / g or less per 1 g (mass) of the fibrous cellulose, more preferably 3.65 mmol / g or less. It is more preferably 00 mmol / g or less. Here, the unit mmol / g indicates the amount of substituents per 1 g of mass of fibrous cellulose when the counter ion of the phosphate group is a hydrogen ion (H ^+). By setting the amount of the phosphoric acid group introduced within the above range, it is possible to facilitate the miniaturization of the fiber raw material and enhance the stability of the fibrous cellulose. Further, by setting the introduction amount of the phosphoric acid group within the above range, the content of organic onium ions that can be contained in the fibrous cellulose can be set within an appropriate range, whereby the fibrous cellulose is dispersed in the organic solvent. Sex can be effectively enhanced.

The amount of phosphoric acid group introduced into the fibrous cellulose can be measured by, for example, a conductivity titration method. In the measurement by the conductivity titration method, the introduction amount 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 the fibrous cellulose having a phosphoric acid group and the electrical conductivity. The amount of phosphoric acid group introduced into the fibrous cellulose is measured, for example, as follows. First, the slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, the defibration treatment similar to the defibration treatment step described later may be performed on the measurement target before the treatment with the strongly acidic ion exchange resin. Next, the change in electrical conductivity is observed while adding an aqueous sodium hydroxide solution to obtain a titration curve as shown in FIG. As shown in FIG. 1, the electrical conductivity drops sharply at first (hereinafter referred to as "first region"). After that, the conductivity begins to increase slightly (hereinafter referred to as "second region"). After that, the increment of conductivity increases (hereinafter referred to as "third region"). The boundary point between the second region and the third region is defined by the point at which the second derivative value of the conductivity, that is, the amount of change in the increment (slope) of the conductivity is maximized. Thus, three regions appear on the titration curve. Of these, the amount of alkali required in the first region is equal to the amount of strong acid 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 phosphoric acid group causes condensation, the weakly acidic group is apparently lost, and the amount of alkali required for the second region is smaller than the amount of alkali required for the first region. On the other hand, the amount of strongly acidic groups is consistent with the amount of phosphorus atoms regardless of the presence or absence of condensation. Therefore, when the amount of phosphate group introduced (or amount of phosphate group) or the amount of substituent introduced (or amount of substituent) is simply referred to, it means the amount of strongly acidic group. Therefore, the value obtained by dividing the amount of alkali (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 amount of phosphoric acid group introduced (mmol / mmol /). g).

In the measurement of the amount of substituents by the titration method, if the titration interval of the aqueous sodium hydroxide solution is too short, the amount of substituents may be lower than the original amount. Therefore, an appropriate titration interval, for example, 0.1 N hydroxide. It is desirable to titrate 50 μL of the aqueous sodium solution every 30 seconds.

<Manufacturing process of fine fibrous cellulose>
<Fiber raw material>
Fine fibrous cellulose is produced from a fiber raw material containing cellulose. The fiber raw material containing cellulose is not particularly limited, but pulp is preferably used because it is easily available and inexpensive. Examples of pulp include wood pulp, non-wood pulp, and deinked pulp. The wood pulp is not particularly limited, but is, for example, broadleaf kraft pulp (LBKP), coniferous kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), and unbleached kraft pulp (UKP). ) And chemical pulp such as oxygen bleached kraft pulp (OKP), semi-chemical pulp such as semi-chemical pulp (SCP) and chemiground wood pulp (CGP), crushed wood pulp (GP) and thermomechanical pulp (TMP, BCTMP), etc. Examples include mechanical pulp. The non-wood pulp is not particularly limited, and examples thereof include cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as hemp, straw and bagasse. The deinking pulp is not particularly limited, and examples thereof include deinking pulp made from recycled paper. As the pulp of the present embodiment, one of the above types may be used alone, or two or more types may be mixed and used.
Among the above pulps, for example, wood pulp and deinked pulp are preferable from the viewpoint of availability. Further, among wood pulps, from the viewpoint of high cellulose ratio and high yield of fine fibrous cellulose during defibration treatment, long fiber fine fibrous cellulose having a small decomposition of cellulose in pulp and a large axial ratio can be obtained. From the viewpoint, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are further preferable. When long fiber fine fibrous cellulose having a large axial ratio is used, the viscosity tends to be high.

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

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

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

As an example of the method of allowing the compound A to act on the fiber raw material in the coexistence with the compound B, a method of mixing the compound A and the compound B with the fiber raw material in a dry state, a wet state or a slurry state can be mentioned. Of these, since the reaction uniformity is high, it is preferable to use a fiber raw material in a dry state or a wet state, and it is particularly preferable to use a fiber raw material in a dry state. The form of the fiber raw material is not particularly limited, but is preferably cotton-like or thin sheet-like, for example. Examples of the compound A and the compound B include a method of adding the compound A and the compound B to the fiber raw material in the form of a powder or a solution dissolved in a solvent, or in a state of being heated to a melting point or higher and melted. Of these, since the reaction is highly homogeneous, it is preferable to add the mixture in the form of a solution dissolved in a solvent, particularly in the form of an aqueous solution. Further, the compound A and the compound B may be added to the fiber raw material at the same time, may be added separately, or may be added as a mixture. The method of adding the compound A and the compound B is not particularly limited, but when the compound A and the compound B are in the form of a solution, the fiber raw material may be immersed in the solution to absorb the liquid and then taken out, or the fiber raw material may be taken out. The solution may be dropped into the water. Further, the required amounts of compound A and compound B may be added to the fiber raw material, or after the excess amounts of compound A and compound B are added to the fiber raw material, respectively, the surplus compound A and compound B are added by pressing or filtering. It may be removed.

Examples of the compound A used in this embodiment include compounds having a phosphorus atom and capable of forming an ester bond with cellulose. Specifically, phosphoric acid or a salt thereof, phosphoric acid or a salt thereof, dehydration condensation, and the like. Phosphoric acid or a salt thereof, anhydrous phosphoric acid (diphosphoric pentoxide) and the like can be mentioned, but are not particularly limited. As the phosphoric acid, those having various puritys can be used, and for example, 100% phosphoric acid (normal phosphoric acid) or 85% phosphoric acid can be used. Examples of phosphorous acid include 99% phosphorous acid (phosphonic acid). The dehydration-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 phosphates, phosphites, and dehydration-condensed phosphates include lithium salts, sodium salts, potassium salts, and ammonium salts of phosphoric acid, phosphite or dehydration-condensed phosphoric acid, and these are among various types. It can be a sum. Of these, from the viewpoints of high efficiency of introduction of phosphoric acid group, easy improvement of defibration efficiency in the defibration step described later, low cost, and easy industrial application, phosphoric acid and phosphoric acid 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 compound A added to the fiber raw material is not particularly limited, but for example, when the amount of compound A added is converted to the phosphorus atomic weight, the amount of phosphorus atom added to the fiber raw material (absolute dry mass) is 0.5% by mass or more. It is preferably 100% by mass or less, more preferably 1% by mass or more and 50% by mass or less, and further preferably 2% by mass or more and 30% by mass or less. By setting the amount of phosphorus atom added to the fiber raw material within the above range, the yield of fine fibrous cellulose can be further improved. On the other hand, by setting the addition amount of the phosphorus atom to the fiber raw material to be equal to or less than the above upper limit value, the effect of improving the yield and the cost can be balanced.

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

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

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

In the 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 heat-treat the fiber raw material. As the heat treatment temperature, it is preferable to select a temperature at which the phosphate group can be efficiently introduced while suppressing the thermal decomposition and hydrolysis reaction of the fiber. The heat treatment temperature is, for example, preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower. In addition, equipment having various heat media can be used for the heat treatment, for example, a stirring drying device, a rotary drying device, a disk drying device, a roll type heating device, a plate type heating device, a fluidized layer drying device, and an air flow. A drying device, a vacuum drying device, an infrared heating device, a far infrared heating device, and a microwave heating device can be used.

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

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

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

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

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

<Alkaline treatment process>
When producing fine fibrous cellulose, an alkali treatment may be performed on the fiber raw material between the phosphate group introduction step and the defibration treatment step described later. The alkaline treatment method is not particularly limited, and examples thereof include a method of immersing the phosphate group-introduced fiber in an alkaline solution.

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

The temperature of the alkaline solution in the alkaline treatment step is not particularly limited, but is preferably 5 ° C. or higher and 80 ° C. or lower, and more preferably 10 ° C. or higher and 60 ° C. or lower. The immersion time of the phosphoric acid group-introduced fiber in the alkaline solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes or more and 30 minutes or less, and more preferably 10 minutes or more and 20 minutes or less. The amount of the alkaline solution used in the alkaline treatment is not particularly limited, but is preferably 100% by mass or more and 100,000% by mass or less, and 1000% by mass or more and 10,000% by mass or less, for example, with respect to the absolute dry mass of the phosphate group-introduced fiber. Is more preferable.

In order to reduce the amount of the alkaline 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. From the viewpoint of improving handleability, it is preferable to wash the alkali-treated phosphate group-introduced fibers with water or an organic solvent after the alkali treatment step and before the defibration treatment step.

<Acid treatment process>
When producing fine fibrous cellulose, the fiber raw material may be subjected to acid treatment between the step of introducing a phosphoric acid group and the defibration treatment step described later. For example, the phosphoric acid group introduction step, the acid treatment, the alkali treatment, and the defibration treatment may be performed in this order.

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

The temperature of the acid solution in the acid treatment is not particularly limited, but is preferably 5 ° C. or higher and 100 ° C. or lower, and more preferably 20 ° C. or higher and 90 ° C. or lower. The immersion time in the acid solution in the acid treatment is not particularly limited, but is preferably 5 minutes or more and 120 minutes or less, and more preferably 10 minutes or more and 60 minutes or less. The amount of the acid solution used in the acid treatment is not particularly limited, but is preferably 100% by mass or more and 100,000% by mass or less, and 1,000% by mass or more and 10,000% by mass or less, for example, with respect to the absolute dry mass of the fiber raw material. Is more preferable.

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

In the defibration 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 selected from water and an organic solvent such as a polar organic solvent can be used. The polar organic solvent is not particularly limited, but for example, alcohols, polyhydric alcohols, ketones, ethers, esters, aprotic polar solvents and the like are preferable. Examples of alcohols include methanol, ethanol, isopropanol, n-butanol, isobutyl alcohol and the like. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin and the like. Examples of the ketones include acetone, methyl ethyl ketone (MEK) and the like. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monon-butyl ether, propylene glycol monomethyl ether and the like. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the aprotonic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP) and the like.

The solid content concentration of the fine fibrous cellulose during the defibration treatment can be appropriately set. Further, the slurry obtained by dispersing the phosphate group-introduced fibers in a dispersion medium may contain solids other than the phosphate group-introduced fibers such as urea having a hydrogen bond property.

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

The organic onium ion satisfies at least one of the conditions selected from the following (a) and (b).
(A) Contains a hydrocarbon group having 5 or more carbon atoms.
(B) The total number of carbon atoms is 17 or more.
That is, in the fibrous cellulose, at least one selected from an organic onium ion containing a hydrocarbon group having 5 or more carbon atoms and an organic onium ion having a total carbon number of 17 or more is derived from a phosphoric acid group or a phosphoric acid group. Included as a counterion of the substituent. By satisfying at least one of the conditions selected from the above (a) and (b) for the organic onium ion, the dispersibility of the fibrous cellulose in the organic solvent can be more effectively enhanced.

The hydrocarbon group having 5 or more carbon atoms is preferably an alkyl group having 5 or more carbon atoms or an alkylene group having 5 or more carbon atoms, and an alkyl group having 6 or more carbon atoms or an alkylene group having 6 or more carbon atoms. It is more preferably a 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 preferable to have. Among them, the organic onium ion preferably has an alkyl group having 5 or more carbon atoms, and 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 above general formula (A), M is preferably a nitrogen atom or a phosphorus atom, and R _{1 to} R ₄ independently represent a hydrogen atom or an organic group, respectively. However, _{it is preferable that at least one of R 1 to} R ₄ is an organic group having 5 or more carbon atoms, or the total number of carbon atoms of _{R 1 to} R _{4 is 17 or more.}
Above all, M is preferably a nitrogen atom. That is, the organic onium ion is preferably an organic ammonium ion. Further, _{it is preferable that at least one of R 1 to} R ₄ is an alkyl group having 5 or more carbon atoms, and the total number of carbon atoms of _{R 1 to} R _{4 is 17 or more.}

Examples of such organic onium ions include lauryltrimethylammonium, cetyltrimethylammonium, stearyltrimethylammonium, octyldimethylethylammonium, lauryldimethylethylammonium, didecyldimethylammonium, lauryldimethylbenzylammonium, tributylbenzylammonium, and methyltri-n. -Octylammonium, hexylammonium, n-octylammonium, dodecylammonium, tetradecylammonium, hexadecylammonium, stearylammonium, N, N-dimethyldodecylammonium, N, N-dimethyltetradecylammonium, N, N-dimethylhexadecyl Ammonium, N, N-dimethyl-n-octadecylammonium, dihexylammonium, di (2-ethylhexyl) ammonium, din-octylammonium, didecylammonium, didodecylammonium, didecylmethylammonium, N, N-didodecylmethyl Ammonium, polyoxyethylene dodecylammonium, alkyldimethylbenzylammonium, di-n-alkyldimethylammonium, behenyltrimethylammonium, tetraphenylphosphonium, tetraoctylphosphonium, acetonyltriphenylphosphonium, allyltriphenylphosphonium, amyltriphenylphosphonium, benzyl Examples thereof include triphenylphosphonium, ethyltriphenylphosphonium, diphenylpropylphosphonium, triphenylphosphonium, tricyclohexylphosphonium, tri-n-octylphosphonium and the like. Examples of the alkyl group in alkyldimethylbenzylammonium and di-n-alkyldimethylammonium include linear alkyl groups having 8 or more and 18 or less 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 bonded groups is less than 4, 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 remaining one to form an organic onium ion.

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

The molecular weight of the organic onium ion is preferably 2000 or less, and more preferably 1800 or less. By setting the molecular weight of the organic onium ion within the above range, the handleability of the fibrous cellulose can be improved. Further, by setting the molecular weight of the organic onium ion within the above range, it is possible to 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 2.0% by mass or more with respect to the total mass of the solid body. Is even more preferable. The content of organic onium ions is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total mass of the solid body.

The content of the organic onium ion in the solid body is preferably 0.5 to 2 times the molar amount of the phosphoric acid group contained in the fibrous cellulose, but is not particularly limited. .. The content of organic onium ions can be measured by tracking atoms typically contained in organic onium ions. Specifically, when the organic onium ion is an ammonium ion, the amount of a nitrogen atom is measured, and when the organic onium ion is a phosphonium ion, the amount of a phosphorus atom is measured. When the fibrous cellulose contains nitrogen atoms and phosphorus atoms in addition to the organic onium ions, the amount of the target atoms is measured after performing a method of extracting only the organic onium ions, for example, an extraction operation with an acid. 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 organic onium ions, and as a result, it becomes easy to reduce the water absorption rate of the solid body.

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

Resins include polyolefin resins, acrylic resins, polycarbonate resins, polyester resins, polyamide resins, silicone resins, fluorine resins, chlorine resins, epoxy resins, melamine resins, phenol resins, and polyurethane resins. Examples thereof include resins, diallyl phthalate resins, alcohol resins, cellulose derivatives, and precursors of these resins. Examples of the cellulose derivative include carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose and the like.

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

The 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 (for example, 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 seeds) , Arginic acid, purulan, carrageenan, pectin, etc.), cationized starch, raw starch, oxidized starch, etherified starch, esterified starch, starches such as amylose, glycerin such as glycerin, diglycerin, polyglycerin, etc., hyaluronic acid , Metallic salt of hyaluronic acid and the like.

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 content contained in the solid body. It is more preferably 20% by mass or less. Further, the content of the resin contained in the solid body may be 1% by mass or more with respect to the total mass of the solid content 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 substantially not contained means a case where the content of the resin with respect to the total mass of the solid content contained in the solid body is less than 1% by mass.

The solid body may further contain other optional components. Examples of the optional component include a hygroscopic agent. Examples of the hygroscopic agent include silica gel, zeolite, alumina, carboxymethyl cellulose, polyvinyl alcohol water-soluble cellulose acetate, polyethylene glycol, sepiolite, calcium oxide, sodium citrate, activated charcoal, active white clay, white carbon, calcium chloride, magnesium chloride, and potassium acetate. , Second sodium phosphate, sodium citrate, water-absorbent polymer 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 protective agents, etc. Dyes, pigments, stabilizers, magnetic powders, orientation promoters, plasticizers, dispersants, cross-linking agents and the like can be mentioned.

The content of the optional component 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 content contained in the solid body. , 20% by mass or less is more preferable.

The solid body may contain an organic solvent as an optional component. The organic solvent is not particularly limited, but is, 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, Diethyl ether chloroform and the like can be mentioned. The content of the organic solvent in the solid body is preferably 10% by mass or less, more preferably 5% by mass or less, and 1% by mass, based on the total mass of the solid content contained in the solid body. It is more preferably less than or equal to%.

(Manufacturing method of solid body)
The method for producing a solid body is as follows: a fibrous cellulose having a fiber width of 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group is organic as a counter ion of a phosphoric acid group or a substituent derived from a phosphoric acid group. It is preferable to include a step of obtaining a composition containing onium ions and a non-aqueous first solvent, and a step of forming a solid body from the composition. Here, the organic onium ion satisfies at least one of the conditions selected from the following (a) and (b).
(A) Contains a hydrocarbon group having 5 or more carbon atoms.
(B) The total number of carbon atoms is 17 or more.

Fibrous cellulose having a fiber width of 1000 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 a substituent derived from the phosphate group, and a non-aqueous first. The composition containing the solvent is a step of adding an organic onium ion or a compound that forms an organic onium ion by neutralization to a fine fibrous cellulose-containing slurry to obtain a fine fibrous cellulose concentrate, and the obtained fine particles. It is preferable to include a step of dispersing the fibrous cellulose concentrate in a 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 added as an aqueous solution containing the organic onium ion.

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

In addition, organic onium ions may be produced only after being neutralized by an acid, such as dodecylamine. In this case, the organic onium ion is obtained by the reaction of the compound that forms the organic onium ion by neutralization with the 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 organic onium by neutralization may be directly added to the fibrous cellulose-containing slurry, and the phosphoric acid group contained in the fibrous cellulose may be used as a counterion to ionize the organic onium.

The amount of organic onium ions added 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. It is more preferable, and it is particularly preferable that it is 100% by mass or more. The amount of organic onium ions added is preferably 1000% by mass or less with respect to the total mass of the fibrous cellulose.
The number of moles of organic onium ions to be added is preferably 0.2 times or more, preferably 0.5 times or more, the value obtained by multiplying the amount (number of moles) of phosphate groups contained in the fibrous cellulose by the valence. Is more preferable, and 1.0 times or more is further preferable. 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 (number of moles) of the phosphate groups contained in the fibrous cellulose by the valence.

When organic onium ions are added and stirred, aggregates are formed in the fibrous cellulose-containing slurry. This agglomerate is agglomerated of fibrous cellulose having an organic onium ion as a counter ion. The fibrous cellulose concentrate can be recovered by filtering the fibrous cellulose-containing slurry in which aggregates are formed 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 content of N atoms (value of N / P) to the content of P atoms in the obtained fibrous cellulose concentrate is preferably larger than 1.2, and more preferably larger than 2.0. preferable. Further, the ratio of the content of N atoms (value of N / P) to the content of P atoms 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, elemental analysis may be performed after separating the composition and the fibrous cellulose concentrate by an appropriate method.

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 further preferably 20% by mass or more. The solid content concentration of the fibrous cellulose concentrate is preferably 99.5% by mass or less. A step of drying the fibrous cellulose concentrate may be provided so that the solid content concentration of the fibrous cellulose concentrate is within a desired range.

The step of dispersing the obtained fine fibrous cellulose concentrate in a 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, and 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), dimethylsulfoxide (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 kinds of these organic solvents may be used. Of these, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), methyl ethyl ketone (MEK), toluene, and methanol are preferably used.

The relative permittivity of the non-aqueous first solvent at 25 ° C. is preferably 60 or less, 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 permittivity, the relative permittivity of the non-aqueous first solvent at 25 ° C. is set. 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 12 MPa ^1/2 or more and 18 MPa ^1/2 or less is further preferable. 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 It is more preferably 20 MPa ^{1/2 or less.} Further, .delta.p is in the range of 0 MPa ^1/2 or 4 MPa ^1/2 or less, it is also preferred to simultaneously satisfy the δh is in a range of 0 MPa ^1/2 or 6 MPa ^1/2 or less.

As the disperser used when dispersing the fine fibrous cellulose concentrate in the non-aqueous first solvent, for example, the same disperser as the defibration treatment device described in the above defibration treatment can be used. Further, the fine fibrous cellulose concentrate may be dispersed in an organic solvent by subjecting it to ultrasonic treatment.

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

Further, in the step of forming a solid body from the composition, a fibrous cellulose having a fiber width of 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group is substituted with a phosphoric acid group or a phosphoric acid group. In the step of contacting a composition containing an organic onium ion as a pair 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 contact step, whereby the water absorption rate and the yellowness of the solid body can be reduced more effectively.

In the second solvent contact step, the composition obtained in the step of obtaining the composition is brought into contact with the second solvent having ^{the hydrogen bond term (δh) of the Hansen solubility parameter of 12.0 MPa 1/2 or more.} Examples of the second solvent in which the hydrogen bond term (δh) of the Hansen solubility parameter is 12.0 MPa ^1/2 or more include water, methanol, ethanol, n-propyl alcohol, isopropyl alcohol (IPA), 1-butanol, and m. -Cresol, glycerin, acetic acid and the like can be mentioned. Further, a mixed solvent obtained by mixing two or more kinds 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 non-aqueous first solvent and the second solvent used in the method for producing a solid body are preferably compatible with each other. The difference in the hydrogen bond term (δh) of the Hansen solubility parameter between the non-aqueous 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. It is more preferably ^{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 even more preferably 60 or more. Further, the 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 10 MPa ^1/2 or more and 20 MPa ^1/2 or less. Is more preferable. 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 contact 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 in the form of filaments, it is preferable to include a step of injecting the composition into the second solvent in the form of threads, and if the solid body is in the form of beads, the composition is dropped into the second solvent. It is preferable to include a step of performing. When the solid body 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 molding mold may be immersed in the second solvent. When the sheet precursor is immersed in the second solvent, the sheet molding mold may be immersed in the second solvent.

In the step of contacting the composition with the second solvent, it is preferable to contact the composition with a second solvent having a volume 40 times or more the total volume of the composition. That is, it is preferable that the composition is present in a second solvent atmosphere. In addition, the second solvent may be replaced or circulated as needed.

By contacting the composition with the second solvent, the non-aqueous first solvent is removed and a solid body is formed. The step of producing the solid body preferably includes a step of bringing the composition into contact with the second solvent and then further immersing the solid body obtained in the step in the second solvent for a certain period of time or longer. In this case, it is preferable to immerse the solid body in the second solvent for 1 hour or more, more preferably 5 hours or more, and further preferably 8 hours or more. The upper limit of the immersion time is not particularly limited, but is preferably 100 hours or less, for example.

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

(Composition containing fibrous cellulose)
The present invention may relate to a fibrous cellulose-containing composition obtained by redispersing the solid body obtained through the above-mentioned steps 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. It also has excellent dimensional stability. In addition, the resin complex formed from the fibrous cellulose-containing composition is also excellent in transparency.

The resin composite formed from the fibrous cellulose-containing composition may be a sheet, and in this case, the method for forming the sheet includes a step of applying the above-mentioned fibrous cellulose-containing composition onto the substrate. Is preferable. The material of the base material used in the coating process is not particularly limited, but a material having high wettability to the composition may suppress shrinkage of the sheet during drying, but the sheet formed after drying may be used. It is preferable to select one that can be easily peeled off. Of these, a resin film or plate or a metal film or plate is preferable, but is not particularly limited. For example, resin films and plates such as acrylic, polyethylene terephthalate, vinyl chloride, polystyrene, polypropylene, polycarbonate, and polyvinylidene chloride, metal films and plates of aluminum, zinc, copper, and iron plates, and their surfaces are oxidized. , Stainless film or plate, brass film or plate, etc. can be used.

In the coating process, when the viscosity of the composition is low and it develops on the base material, a dammed frame is fixed on the base material to obtain a sheet with a predetermined thickness and basis weight. You may. The frame for damming is not particularly limited, but it is preferable to select, for example, a frame in which the end portion of the sheet that adheres after drying can be easily peeled off. From this point of view, a resin plate or a metal plate molded is more preferable. In the present embodiment, for example, a resin plate such as an acrylic plate, a polyethylene terephthalate plate, a vinyl chloride plate, a polystyrene plate, a polypropylene plate, a polycarbonate plate, a polyvinylidene chloride plate, or a metal plate such as an aluminum plate, a zinc plate, a copper plate, or an iron plate. , And those whose surfaces are oxidized, stainless steel plates, brass plates and the like can be used.

The coating machine for coating the 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. A die coater, a curtain coater, and a spray coater are particularly preferable because the thickness of the coating film (sheet) can be made more uniform.

The temperature and atmospheric temperature of the liquid composition when the composition is applied to the substrate are not particularly limited, but are preferably 5 ° C. or higher and 80 ° C. or lower, and more preferably 10 ° C. or higher and 60 ° C. or lower. It is more preferably 15 ° C. or higher and 50 ° C. or lower, and particularly preferably 20 ° C. or higher and 40 ° C. or lower.

In the coating process, the composition is prepared so that the finished basis weight of the sheet is preferably 10 g / m ² or more and 100 g / m ² or less, and more preferably 20 g / m ² or more and 60 g / m ^{2 or less.} It is preferable to apply it to the base material. By coating so that the basis weight is within the above range, a sheet having higher strength can be obtained.

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

(Use)
The use of the solid body of the present invention is not particularly limited, but the reinforcing material, the interior material, the exterior material, the packaging material, the electronic material, the optical material, the acoustic material, the process material, the member of the transportation device, the member of the electronic device, and the like. Suitable for applications such as members of electrochemical elements.

When the solid body of the present invention is a filament, it can be used for ropes, fishing lines, medical sutures and the like. In addition, it can be added to resin, rubber, cement, etc. and used as a reinforcing material. Further, a non-woven 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, medical materials, and the like. When the solid body of the present invention is beads, it can be added to a resin or a solvent in addition to an adsorbent and an abrasive, and used as an ink, a paint, a molded body, a film, a coating agent and the like.

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

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

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

The raw material pulp was 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 in a hot air dryer at 165 ° C. for 200 seconds to introduce a phosphoric acid group into the cellulose in the pulp to obtain phosphorylated pulp 1.

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

The phosphorylated pulp 1 after washing was further subjected to the phosphorylation treatment and the washing treatment once in this order.

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

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

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

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

By X-ray diffraction, it was confirmed that this fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. The amount of phosphoric acid group (strong acid group amount) measured by the measuring method described later was 2.0 mmol / g.

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

First, the above-mentioned raw material pulp equivalent to 100 parts by mass of dry mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl), and 10 parts by mass of sodium bromide are added to 10000 parts by mass of water. It was dispersed in the parts. Then, a 13 mass% sodium hypochlorite aqueous solution was added to 1.0 g of 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 or more and 10.5 or less, and the reaction was considered to be completed when no change was observed in the pH.

Next, the obtained TEMPO oxide pulp was washed. The washing treatment is carried out by dehydrating the pulp slurry after TEMPO oxidation to obtain a dehydrated sheet, pouring 5000 parts by mass of ion-exchanged water, stirring and uniformly dispersing the pulp slurry, and then repeating the operation of filtration and dehydration. rice field. When the electrical conductivity of the filtrate became 100 μS / cm or less, the washing end point was set.

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

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

By X-ray diffraction, it was confirmed that this fine fibrous cellulose maintained the cellulose type I crystal. The fiber width of the fine fibrous cellulose was measured using a transmission electron microscope and found to be 3 to 5 nm. The amount of carboxy group measured by the measuring method described later was 1.80 mmol / g.

<Manufacturing example 3>
[Manufacture of fine fibrous cellulose dispersion C]
The same procedure as in Production Example 1 was carried out except that 33 parts by mass of phosphorous acid (phosphonic acid) was used instead of ammonium dihydrogen phosphate to obtain phosphorylated pulp 2.

Next, the obtained phosphorylated pulp 2 was washed. The washing treatment is carried out by repeating the operation of pouring 10 L of ion-exchanged water into 100 g (absolute dry mass) of phosphorylated pulp, stirring the pulp dispersion liquid so that the pulp is uniformly dispersed, and then filtering and dehydrating the pulp. went. When the electrical conductivity of the filtrate became 100 μS / cm or less, the washing end point was set.

Next, the phosphorylated pulp 2 after washing was neutralized as follows. First, the washed phosphorylated pulp 2 is diluted with 10 L of ion-exchanged water, and then a 1N aqueous sodium hydroxide solution is added little by little with stirring to obtain a phosphorylated pulp slurry having a pH of 12 or more and 13 or less. rice field. Next, the phosphorylated pulp slurry was dehydrated to obtain a phosphorylated pulp 2 that had been neutralized. Next, the phosphorylated pulp 2 after the neutralization treatment was subjected to the above-mentioned washing treatment.

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

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

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

The amount of phosphite group (strong acid group amount) measured by the measurement method described later of the obtained phosphorylated pulp 2 was 1.50 mmol / g. The amount of weakly acidic groups was 0.13 mmol / g.

<Manufacturing example 4>
[Manufacture 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; Organo Co., Ltd., conditioned) and has a mesh with a mesh opening of 90 μm at the tip. The operation of press-fitting with a pump was repeated to convert the counterion of the phosphate group of the fine fibrous cellulose into hydrogen ion (H ^+). By this operation, a 2.0% by mass acid-type fine fibrous cellulose dispersion was obtained. After adding 3.10 g of a 55% tetrabutylammonium hydroxide aqueous solution to 100 g of the obtained acid-type fine fibrous cellulose dispersion, the mixture was stirred with a disperser for 24 hours to obtain a fine fibrous cellulose dispersion D. ..

<Example 1>
[Manufacturing 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 obtained in Production Example 1. After stirring for 5 minutes, aggregates were formed in the fine fibrous cellulose dispersion. Fine fibrous cellulose aggregates were obtained by filtering the fine fibrous cellulose dispersion liquid in which aggregates were formed under reduced pressure. By repeatedly washing the obtained fine fibrous cellulose aggregates with ion-exchanged water, excess N, N-didodecylmethylamine, lactic acid, eluted ions and the like contained in the fine fibrous cellulose aggregates were removed. The obtained fine fibrous cellulose aggregate was dried under the conditions of 30 ° C. and 40% relative humidity to obtain a fine fibrous cellulose concentrate.
The counterion 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 the fine fibrous cellulose was 2.0% by mass. Then, sonication was carried out for 10 minutes using an ultrasonic treatment apparatus (Heelshire, UP400S) to obtain a fine fibrous cellulose redispersed slurry.

[Manufacture of fine fibrous cellulose-containing filament]
After filling the fine fibrous cellulose redispersion slurry in a syringe (needle diameter; φ1.5 mm), 10 g of the filling was placed in a coagulation tank filled with ion-exchanged water (second solvent) at the tip of the needle. It was injected into ion-exchanged water at / min to form a fine fibrous cellulose injection in the coagulation tank. After repeating the operation of exchanging the ion-exchanged water in the coagulation tank every 30 minutes three times, the fine fibrous cellulose injection was further immersed in the ion-exchanged water for 12 hours. The fine fibrous cellulose injection after immersion is taken out from the coagulation tank, dried on a hot plate at 70 ° C. for 30 minutes, then raised to 120 ° C. and dried for another 2 hours to obtain a fine fibrous cellulose-containing filament. rice field. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Example 2>
The fine fibrous cellulose dispersion C obtained in Production Example 3 was used instead of the fine fibrous cellulose dispersion A. Same as in Example 1 except that 0.30 g of lactic acid was added to 100 g of a 1.20 mass% N, N-didodecylmethylamine aqueous solution to neutralize it, and then added to the fine fibrous cellulose dispersion C. , Fine fibrous cellulose concentrate, fine fibrous cellulose redispersed slurry, and fine fibrous cellulose-containing filaments were obtained. The counterion of the phosphate group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecylammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 92% by mass. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Example 3>
Using 100 g of an aqueous solution of 1.83% by mass of polyoxyethylene dodecylamine (the number of oxyethylene residues is 2) in place of the N, N-didodecylmethylamine aqueous solution, and using dimethyl sulfoxide (DMSO) as the first solvent, 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 they were used in place of methyl-2-pyrrolidone (NMP). The counterion of the phosphate group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecylammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 92% by mass. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Example 4>
A first solvent using 2.33% by mass of an aqueous solution of alkyldimethylbenzylammonium chloride (the number of carbon atoms in the alkyl chain is 8 to 18) was used in place of the aqueous solution of N, N-didodecylmethylamine neutralized with lactic acid. The fine fibrous cellulose concentrate, the fine fibrous cellulose redispersed slurry, and the fine fibrous cellulose-containing filament were prepared in the same manner as in Example 1 except that methanol was used instead of N-methyl-2-pyrrolidone (NMP). Obtained. The counterion 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 rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Example 5>
100 g of a 3.86 mass% di-n-alkyldimethylammonium chloride aqueous solution (alkyl chain having 16 or 18 carbon atoms) was used in place of the alkyldimethylbenzylammonium chloride aqueous solution, and toluene was used as the first solvent in methanol. Fine fibrous cellulose concentrate, fine fibrous cellulose redispersed slurry, and fine fibrous cellulose 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 counterion of the phosphoric acid group contained in the fine fibrous cellulose concentrate was di-n-alkyldimethylammonium (DADMA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 91% by mass. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Comparative example 1>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A. Same as in Example 1 except that 0.32 g of lactic acid was added to 100 g of 1.32 mass% N, N-didodecylmethylamine aqueous solution to neutralize it, and then added to the fine fibrous cellulose dispersion B. , Fine fibrous cellulose concentrate, fine fibrous cellulose redispersed slurry, and fine fibrous cellulose-containing filaments were obtained. The counterion 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 rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Comparative example 2>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A. In the same manner as in Example 3 except that 100 g of an aqueous solution of 0.99% by mass of polyoxyethylene dodecylamine (the number of oxyethylene residues is 2) pre-neutralized with lactic acid was added to the fine fibrous cellulose dispersion B. , Fine fibrous cellulose concentrate, fine fibrous cellulose redispersed slurry, and fine fibrous cellulose-containing filaments were obtained. The counterion of the carboxy group contained in the fine fibrous cellulose concentrate was polyoxyethylene dodecylammonium ion (POEDA ⁺ ). The solid content concentration of the obtained fine fibrous cellulose concentrate was 90% by mass. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Comparative example 3>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A. A fine fibrous cellulose concentrate, a fine fibrous cellulose redispersed slurry, and a fine fibrous cellulose redispersed slurry in the same manner as in Example 4, except that 100 g of a 1.27 mass% alkyldimethylbenzylammonium aqueous solution was added to the fine fibrous cellulose dispersion B. Fine fibrous cellulose-containing filaments were obtained. The counterion 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 rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Comparative example 4>
The fine fibrous cellulose dispersion B obtained in Production Example 2 was used instead of the fine fibrous cellulose dispersion A. 2. Fine fibrous cellulose concentrate and fine fibrous cellulose reconstituted in the same manner as in Example 5 except that 100 g of a 10 mass% di-n-alkyldimethylammonium chloride aqueous solution was added to the fine fibrous cellulose dispersion B. A dispersed slurry and a filament containing fine fibrous cellulose were obtained. The counterion 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 rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Comparative example 5>
The same as in Example 1 except that the fine fibrous cellulose dispersion A obtained in Production Example 1 was used instead of the fine fibrous cellulose redispersion slurry and ethanol was used as the second solvent instead of ion-exchanged water. A filament containing fine fibrous cellulose was obtained. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Comparative Example 6>
Similar to 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 as the second solvent instead of ethanol. To obtain a filament containing fine fibrous cellulose. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<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 rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing filament were measured and evaluated by the method described later.

<Example 6>
The fine fibrous cellulose redispersed slurry obtained in the same manner as in Example 1 was filled in a syringe (needle diameter; φ1.5 mm) and then dropped into a coagulation tank filled with ion-exchanged water (second solvent) at a rate of 2 g / min. Then, a fine fibrous cellulose injection was formed in the coagulation tank. After repeating the operation of exchanging the ion-exchanged water in the coagulation tank every 30 minutes three times, the fine fibrous cellulose injection was further immersed in the ion-exchanged water for 12 hours. The fine fibrous cellulose ejected product after immersion is taken out from the coagulation tank and dried on a hot plate at 70 ° C. for 30 minutes, and then the temperature is raised to 120 ° C. and dried for another 2 hours to obtain fine fibrous cellulose-containing beads. rice field. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<Example 7>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 6 except that the fine fibrous cellulose redispersed slurry obtained in Example 2 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<Example 8>
The fine fibrous cellulose-containing slurry was obtained in the same manner as in Example 6 except that the fine fibrous cellulose redispersed slurry obtained in Example 3 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<Example 9>
The fine fibrous cellulose-containing slurry was obtained in the same manner as in Example 6 except that the fine fibrous cellulose redispersed slurry obtained in Example 4 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

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

<Comparative Example 8>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 6 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 1 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<Comparative Example 9>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 6 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 2 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<Comparative Example 10>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 6 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 3 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<Comparative Example 11>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 10 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 4 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 5. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<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 as the second solvent instead of ion-exchanged water. Obtained fine fibrous cellulose-containing beads in the same manner as in Example 6. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

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

<Comparative Example 14>
The fine fibrous cellulose-containing liquid B was used in place of the fine fibrous cellulose dispersion A obtained in Production Example 1 in the same manner as in Comparative Example 12, except that the fine fibrous cellulose dispersion B obtained in Production Example 2 was used in place of the fine fibrous cellulose dispersion A obtained in Production Example 1. Obtained beads. The water absorption rate and yellowness (YI ₀ ) of the obtained fine fibrous cellulose-containing beads were measured and evaluated by the method described later.

<Example 11>
The fine fibrous cellulose redispersed slurry obtained in the same manner as in Example 1 was ^{poured into a glass petri dish so as to have a basis weight of 80 g / m 2,} and the glass petri dish was filled with ion-exchanged water (second solvent) in a coagulation tank. Soaked gently. After repeating the operation of exchanging the ion-exchanged water in the coagulation tank every 30 minutes three times and then immersing the ion-exchanged water in the ion-exchanged water for another 12 hours, a hydrous fine fibrous cellulose-containing sheet was obtained. The water-containing fine fibrous cellulose was taken out from the coagulation tank and dried on a hot plate at 70 ° C. for 30 minutes, and then the temperature was raised to 120 ° C. and dried for another 2 hours to obtain a fine fibrous cellulose-containing sheet. The water absorption rate, 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>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 11 except that the fine fibrous cellulose redispersed slurry obtained in Example 2 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. I got a sheet. The water absorption rate, 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>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 11 except that the fine fibrous cellulose redispersed slurry obtained in Example 3 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. I got a sheet. The water absorption rate, 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>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 11 except that the fine fibrous cellulose redispersed slurry obtained in Example 4 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. I got a sheet. The water absorption rate, 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 in place of the fine fibrous cellulose redispersed slurry obtained in Example 1 and methanol was used as the second solvent instead of ion-exchanged water. , A fine fibrous cellulose-containing sheet was obtained in the same manner as in Example 11. The water absorption rate, 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>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 11 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 1 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. Obtained beads. A sheet containing fine fibrous cellulose was obtained. The water absorption rate, 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>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 11 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 2 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. I got a sheet. The water absorption rate, 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>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 11 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 3 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 1. I got a sheet. The water absorption rate, 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>
The fine fibrous cellulose-containing slurry was contained in the same manner as in Example 15 except that the fine fibrous cellulose redispersed slurry obtained in Comparative Example 4 was used in place of the fine fibrous cellulose redispersed slurry obtained in Example 5. I got a sheet. The water absorption rate, 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>
The fine fibrous cellulose-containing liquid A obtained in Production Example 1 was used in place of the fine fibrous cellulose redispersion slurry obtained in Example 1 in the same manner as in Example 11. I got a sheet. The water absorption rate, 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>
Comparison except that the fine fibrous cellulose dispersion D obtained in Production Example 4 was used in place of the fine fibrous cellulose dispersion A obtained in Production Example 1 and tetrahydrofuran was used as the second solvent instead of ethanol. A fine fibrous cellulose-containing sheet was obtained in the same manner as in Example 19. The water absorption rate, 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>
The fine fibrous cellulose-containing liquid B was used in place of the fine fibrous cellulose dispersion A obtained in Production Example 1 in the same manner as in Comparative Example 19 except that the fine fibrous cellulose dispersion B obtained in Production Example 2 was used in place of the fine fibrous cellulose dispersion A obtained in Production Example 1. I got a sheet. The water absorption rate, 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 amount]
The amount of phosphate groups in the fine fibrous cellulose is a fibrous form prepared by diluting a fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content is 0.2% by mass. The cellulose-containing slurry was treated with an ion-exchange resin and then titrated with an alkali for measurement.
In the treatment with the ion exchange resin, a strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, which has been conditioned) with a volume of 1/10 is added to the above fibrous cellulose-containing slurry, and the mixture is shaken for 1 hour. , The resin and the slurry were separated by pouring on a mesh having a mesh size of 90 μm.
For titration using alkali, a 0.1 N sodium hydroxide aqueous solution is added to the fibrous cellulose-containing slurry treated with an ion exchange resin once every 30 seconds by 50 μL, and the electrical conductivity exhibited by the slurry. This was done by measuring the change in the value of. For the amount of phosphoric acid group (mmol / g), the amount of alkali (mmol) required in the region corresponding to the first region shown in FIG. 1 of the measurement results is divided by the solid content (g) in the slurry to be titrated. Was calculated.

[Measurement of carboxy group amount]
The amount of carboxy group of the fine fibrous cellulose is a fibrous cellulose prepared by diluting a fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content is 0.2% by mass. The contained slurry was treated with an ion exchange resin and then titrated with an alkali to measure the content.
In the treatment with the ion exchange resin, a strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, which has been conditioned) with a volume of 1/10 is added to the above fibrous cellulose-containing slurry, and the mixture is shaken for 1 hour. , The resin and the slurry were separated by pouring on a mesh having a mesh size of 90 μm.
In the titration using alkali, 50 μL of a 0.1 N sodium hydroxide aqueous solution is added to the fibrous cellulose-containing slurry treated with an ion exchange resin once every 30 seconds to obtain the electrical conductivity of the slurry. This was done by measuring the change in value. The amount of carboxy group (mmol / g) is obtained by dividing the amount of alkali (mmol) required in the region corresponding to the first region shown in FIG. 2 of the measurement results by the solid content (g) in the slurry to be titrated. Calculated.

[Measurement of water absorption rate of solid body]
The solid body (filament, beads, sheet) was humidity-controlled for 24 hours under the conditions of 23 ° C. and a relative humidity of 50%, and the humidity control weight was measured. Next, the solid body 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. From the above humidity control weight and wet weight, the water absorption rate (%) of the solid body was calculated according to the following formula.
Water absorption rate (%) = 100 x (wet weight-humidity control weight) / humidity control weight

[Measurement of yellowness (YI ₀ ) of solid body]
The fine fibrous cellulose-containing solid body was pulverized for 5 minutes using a lab miller (IFM-800; Iwatani Corp.) to obtain a powder. The obtained powder was press-molded at a surface pressure of 600 MPa for 1 minute using a tablet molding compressor (BRE-30; Maekawa Testing Machine Mfg. Co., Ltd.) so that the basis weight was 3000 g / m ^{2, and pellets for yellowness measurement were obtained.} rice field. The yellowness of the obtained pellets was measured using a spectrophotometer (Spectroeye; Gretag Macbeth) according to ASTM E313.

[Calculation of sheet yellowness YI _100]
The yellowness (YI) of the fine fibrous cellulose-containing sheets obtained in Examples 11 to 15 and Comparative Examples 15 to 21 was determined by using Color Cutei (manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K 7373. It was measured. _{Next, the yellowness (YI 100} ) of the sheet converted to a film thickness of 100 μm was calculated using the following conversion formula.
_{Sheet yellowness (YI 100} ) converted to film thickness 100 μm = sheet yellowness (YI) × (100 (μm)) / (sheet film thickness (μm))
The film thickness of the sheet was measured according to JIS K 6783 using a constant pressure thickness measuring device (PG-02; Teclock Co., Ltd.).

In the examples, solid bodies having low water absorption and yellowness were obtained. On the other hand, in the comparative example, low water absorption and low yellowness were not compatible.

Claims (8)

A solid state in which the fiber width is 1000 nm or less and contains a fibrous cellulose having a phosphoric acid group or a substituent derived from a phosphoric acid group and an organic onium ion as a counter ion of the phosphoric acid group or the substituent derived from the phosphoric acid group. The body
The organic onium ion is a solid body that satisfies at least one of the following conditions (a) and (b).
(A) Contains a hydrocarbon group having 5 or more carbon atoms;
(B) The total number of carbon atoms is 17 or more. The solid body 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 phosphoric acid groups or the amount of substituents derived from the phosphoric acid groups in the fibrous cellulose is 0.50 mmol / g or more. The solid state according to any one of claims 1 to 3, wherein the solid content concentration is 80% by mass or more. The solid body according to any one of claims 1 to 4, which is a molded body. The solid body according to any one of claims 1 to 5, which is in the form of a sheet. The solid body according to any one of claims 1 to 6, further comprising a resin. A fibrous cellulose having a fiber width of 1000 nm or less and having a phosphoric acid group or a substituent derived from a phosphoric acid group, an organic onium ion as a counter ion of the phosphoric acid group or a substituent derived from the phosphoric acid group, and a non-hydrogenated. Including a step of bringing the composition containing one solvent 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.}
The organic onium ion is a method for producing a solid body, which satisfies at least one of the following conditions (a) and (b).
(A) Contains a hydrocarbon group having 5 or more carbon atoms;
(B) The total number of carbon atoms is 17 or more.

Images