JP2020033398A - Fine fibrous cellulose-containing composition and method for producing the same - Google Patents

Abstract

To provide a fine fibrous cellulose-containing composition that can lower the viscosity of a fine fibrous cellulose fluid dispersion without changing the concentration of the fine fibrous cellulose, and to provide a method for producing the same.SOLUTION: Provided is a fine fibrous cellulose-containing composition, containing a fine fibrous cellulose having a fiber width of 1,000 nm or less, and chlorine-containing oxo acid or a salt thereof, and in which the content of chlorine-containing oxo acid or a salt thereof for 100 pts.mass of fine fibrous cellulose is 0.0001 pts.mass or more and 10 pts.mass or less.SELECTED DRAWING: None

Description

  The present invention relates to a fine fibrous cellulose-containing composition and a method for producing the same.

Fine fibrous cellulose having a fiber width of 1,000 nm or less is called cellulose nanofiber, and is used as a reinforcing material for composite materials, high-performance filters, displays and solar cells, electronics, transportation equipment, building materials, medical materials, and various other fields. Expected to expand to.
Generally, fine fibrous cellulose is obtained as a dispersion, but the dispersion has a high viscosity. For example, when a film is formed on a substrate, if the concentration of the dispersion is too high, it may be applied uniformly. Have difficulty. On the other hand, when the dispersion liquid is diluted and used for uniform coating, coating and drying must be repeatedly performed until the desired film thickness is achieved, which is inefficient. Was.
Patent Document 1 discloses a method for producing a low-viscosity cellulose nanofiber dispersion in which a pulp having a specific fiber length distribution is selected from wood, and the pulp derived from the wood is defibrated to obtain a cellulose nanofiber dispersion. Are described.

JP 2018-090949 A

In the method described in Patent Document 1, it is necessary to use a specific raw material, and it is difficult to precisely adjust the viscosity of the obtained dispersion.
An object of the present invention is to provide a fine fibrous cellulose-containing composition capable of lowering the viscosity of a fine fibrous cellulose dispersion without changing the concentration of the fine fibrous cellulose, and a method for producing the same. .

The present inventors have found that the above-mentioned problems can be solved by a composition containing fine fibrous cellulose and oxo acid or a salt thereof containing a specific amount of chlorine with respect to the fine fibrous cellulose.
That is, the present invention relates to the following <1> to <8>.
<1> The fiber width includes fine fibrous cellulose having a fiber width of 1,000 nm or less and oxo acid or a salt thereof containing chlorine, and the content of oxo acid or a salt thereof containing chlorine relative to 100 parts by mass of the fine fibrous cellulose is A fine fibrous cellulose-containing composition in an amount of 0.0001 to 10 parts by mass.
<2> The <1> according to <1>, wherein the chlorine-containing oxo acid or a salt thereof includes at least one selected from the group consisting of sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite. A fine fibrous cellulose-containing composition.
<3> When the solid content concentration of the fine fibrous cellulose is 0.4% by mass, the viscosity of the composition measured by rotating at a rotation speed of 3 rpm at 23 ° C. for 3 minutes using a B-type viscometer is as follows: The fine fibrous cellulose-containing composition according to <1> or <2>, which is not more than 1.0 × 10 ⁴ mPa · s.
<4> The fine fibrous cellulose has an ionic substituent, and the content of the ionic substituent is 0.60 mmol / g or more based on the dry mass of the fine fibrous cellulose. The fine fibrous cellulose-containing composition according to any one of <3>.
<5> The fine fiber according to any one of <1> to <4>, wherein the composition has a haze at 23 ° C of 1.5% or less at a solid content concentration of the fine fibrous cellulose of 0.2% by mass. Cellulose-containing composition.
<6> The fine particle according to any one of <1> to <5>, wherein the content of oxo acid or a salt thereof containing chlorine relative to 100 parts by mass of the fine fibrous cellulose is 0.005 to 2 parts by mass. A fibrous cellulose-containing composition.
<7> Step of fibrillating cellulose in a solvent to obtain a dispersion containing fine fibrous cellulose, and adding oxo acid containing chlorine or a salt thereof to the dispersion containing fine fibrous cellulose. A process for producing a fine fibrous cellulose-containing composition, wherein the amount of oxo acid or a salt thereof containing chlorine is 0.0001 to 10 parts by mass per 100 parts by mass of fine fibrous cellulose.
<8> The method for producing a fine fibrous cellulose-containing composition according to <7>, wherein the fibrous cellulose has an ionic substituent.

  According to the present invention, there is provided a fine fibrous cellulose-containing composition capable of lowering the viscosity of a fine fibrous cellulose dispersion without changing the concentration of the fine fibrous cellulose, and a method for producing the same.

FIG. 1 is a graph showing the relationship between the dropping amount of NaOH and the electric conductivity for fine fibrous cellulose having a phosphate group. FIG. 2 is a graph showing the relationship between the dropping amount of NaOH and the electric conductivity for the fine fibrous cellulose having a carboxy group.

[Fine fibrous cellulose-containing composition]
The fine fibrous cellulose-containing composition of the present invention contains fine fibrous cellulose having a fiber width of 1,000 nm or less and oxo acid or a salt thereof containing chlorine, and contains chlorine based on 100 parts by mass of the fine fibrous cellulose. The content of the oxo acid or a salt thereof is 0.0001 to 10 parts by mass.
Conventionally, as a method of lowering the viscosity of the dispersion liquid of fine fibrous cellulose, there is a method of increasing the number of times of the fibrillation treatment step. However, it is difficult to perform precise viscosity control by reducing the viscosity by the fibrillation treatment. In addition, the defibration process has a large time and cost burden.
The fine fibrous cellulose-containing composition of the present invention can lower the viscosity of the fine fibrous cellulose dispersion without changing the concentration of the fine fibrous cellulose. Further, as compared with the method of adjusting the number of times of the defibrating process, the time required for lowering the viscosity is shorter, and the lowering of the viscosity is possible at a lower cost.
Although the detailed reason why the above-mentioned effects can be obtained is unknown, some are presumed as follows. That is, it is considered that by containing oxo acid containing chlorine or a salt thereof, a part of the fine fibrous cellulose is cut in the molecular chain and the molecular weight is reduced, thereby lowering the viscosity of the dispersion. Can be However, the reduction in viscosity by chlorine-containing oxo acids or salts thereof is caused not only by the reduction in molecular weight, but also by the chlorine-containing oxo acids or salts thereof causing aggregation of fine fibrous cellulose to such an extent that haze does not deteriorate. Therefore, it is considered that the viscosity of the dispersion liquid is reduced.
Hereinafter, the present invention will be described in more detail.

<Fine fibrous cellulose>
The fine fibrous cellulose-containing composition of the present invention contains fine fibrous cellulose, and the fine fibrous cellulose is a fibrous cellulose having a fiber width of 1,000 nm or less. The fiber width of the fibrous cellulose can be measured by, for example, observation with an electron microscope.

The fiber width of the fine fibrous cellulose is preferably 100 nm or less, more preferably 30 nm or less, and even more preferably 8 nm or less. Further, the fiber width is preferably 2 nm or more.
The average fiber width of the fine fibrous cellulose is, for example, 1000 nm or less. The average fiber width of the fine fibrous cellulose is, for example, preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, further preferably 2 nm or more and 50 nm or less, and more preferably 2 nm or more and 10 nm or less. Is particularly preferred. By controlling the average fiber width of the fine fibrous cellulose to 2 nm or more, dissolution in water as cellulose molecules is suppressed, and the effect of improving the strength, rigidity, and dimensional stability of the fine fibrous cellulose is more easily exhibited. be able to. The fine fibrous cellulose is, for example, a monofibrous cellulose.

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

  The fiber length of the fine fibrous cellulose is not particularly limited, but is preferably, for example, 0.1 μm to 1000 μm, more preferably 0.1 μm to 800 μm, and more preferably 0.1 μm to 600 μm. More preferred. By setting the fiber length within the above range, destruction of the crystal region of the fine fibrous cellulose can be suppressed. Further, the slurry viscosity of the fine fibrous cellulose can be adjusted to an appropriate range. The fiber length of the fine fibrous cellulose can be determined by, for example, image analysis using TEM, SEM, or AFM.

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

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

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

The fine fibrous cellulose in the present embodiment has, for example, at least one of an ionic substituent and a nonionic substituent. From the viewpoint of improving the dispersibility of the fibers in the dispersion medium and improving the defibration efficiency in the defibration treatment, it is more preferable that the fine fibrous cellulose has an ionic substituent. The ionic substituent may include, for example, one or both of an anionic group and a cationic group. The nonionic substituent may include, for example, an alkyl group, an acyl group, and the like. In the present embodiment, it is particularly preferable to have an anionic group as the ionic substituent.
The treatment for introducing an ionic substituent may not be performed on the fine fibrous cellulose.

  Examples of the anionic group as the ionic substituent include a phosphate group or a substituent derived from a phosphate group (also simply referred to as a phosphate group), a carboxy group or a substituent derived from a carboxy group (simply a carboxy group). And at least one selected from a sulfone group or a substituent derived from a sulfone group (which may be simply referred to as a sulfone group), and at least one selected from a phosphate group and a carboxy group. One type is more preferred, and a phosphate group is particularly preferred.

  The phosphate group or a substituent derived from a phosphate group is, for example, a substituent represented by the following formula (1), and is generalized as a phosphorus oxo acid group or a substituent derived from a phosphorus oxo acid.

In the formula (1), a, b and n are natural numbers (however, a = b × m). Of α ¹ , α ² ,..., α ⁿ and α ′, a is O ⁻ , and the rest are either R or OR. Note that all of α ⁿ and α ′ may be O ⁻ . R represents a hydrogen atom, a saturated-straight-chain hydrocarbon group, a saturated-branched-chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-straight-chain hydrocarbon group, or an unsaturated-branched-chain hydrocarbon group; A hydrogen group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or a derivative thereof.

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

Further, as the deriving group for R, a functional group in which at least one of functional groups such as a carboxy group, a hydroxy group, or an amino group is added or substituted to a main chain or a side chain of the above various hydrocarbon groups. Groups, but are not particularly limited.
The number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R to the above range, the molecular weight of the phosphate group can be adjusted to an appropriate range, facilitating penetration into the fiber material, and increasing the yield of fine cellulose fibers. You can also.

β ^{b +} is a monovalent or higher cation composed of an organic or inorganic substance. Examples of the monovalent or higher cation composed of an organic substance include aliphatic ammonium or aromatic ammonium. Examples of the monovalent or higher cation composed of an inorganic substance include ions of an alkali metal such as sodium, potassium, or lithium; Examples include, but are not particularly limited to, cations of divalent metals such as calcium and magnesium, and hydrogen ions. These can 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 a sodium or potassium ion which is not easily yellowed when a fiber material containing β is heated and is industrially easily used, but is not particularly limited.

The phosphate group is a divalent functional group corresponding to, for example, a phosphoric acid obtained by removing a hydroxy group from phosphoric acid. Is specifically a group represented by -PO ₃ H _2. The substituent derived from the phosphate group includes substituents such as a salt of the phosphate group and a phosphate group. The substituent derived from the phosphate group may be contained in the fine fibrous cellulose as a group in which the phosphate group is condensed (for example, a pyrophosphate group).
Further, the phosphate group may be, for example, a phosphite group (phosphonate group), and the substituent derived from the phosphate group may be a salt of a phosphite group, a phosphite ester group, or the like. Is also good.

The amount of the ionic substituent introduced into the fine fibrous cellulose is, for example, preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, per 1 g (mass) of the fine fibrous cellulose. It is more preferably at least 0.60 mmol / g, particularly preferably at least 1.00 mmol / g. The amount of the ionic substituent introduced into the fine fibrous cellulose is, for example, preferably 3.65 mmol / g or less, more preferably 3.50 mmol / g or less per 1 g (mass) of the fine fibrous cellulose. And more preferably 3.00 mmol / g or less. By setting the introduction amount of the ionic substituent within the above range, the fineness of the fiber raw material can be facilitated, and the stability of the fine fibrous cellulose can be increased. In addition, when the amount of the ionic substituent introduced is within the above range, good characteristics can be exhibited in various uses such as a thickener for fine fibrous cellulose.
Here, the denominator in the unit of mmol / g indicates the mass of fibrous cellulose when the counter ion of the ionic substituent is a hydrogen ion (H ⁺ ).
The amount of the ionic substituent introduced into the fine fibrous cellulose can be measured, for example, by a conductivity titration method. In the measurement by the conductivity titration method, the amount of introduction is measured by determining the change in conductivity while adding an alkali such as an aqueous sodium hydroxide solution to the obtained slurry containing fine fibrous cellulose.

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

Note that the above-mentioned phosphate group introduction amount (mmol / g) indicates the amount of phosphate groups (hereinafter referred to as phosphoric acid) contained in the acid-form fine fibrous cellulose since the denominator indicates the mass of the acid-form fine fibrous cellulose. (Referred to as a basic amount (acid type)). On the other hand, when the counter ion of the phosphate group is substituted by an arbitrary cation C so as to have a charge equivalent, the denominator is converted into the mass of the fine fibrous cellulose when the cation C is the counter ion. By doing so, the amount of phosphate groups (hereinafter, the amount of phosphate groups (C type)) of the fine fibrous cellulose having the cation C as a counter ion can be determined.
That is, it is calculated by the following formula.
Phosphate group amount (C type) = phosphate group amount (acid type) / {1+ (W-1) × A / 1000}
A [mmol / g]: total amount of anions derived from the phosphate groups of the fibrous cellulose (the value obtained by adding the amount of the strongly acidic groups and the amount of the weakly acidic groups of the phosphate groups)
W: Formula weight per valence of cation C (for example, 23 for Na and 9 for Al)

FIG. 2 is a graph showing the relationship between the dropping amount of NaOH and the electric conductivity for the fine fibrous cellulose having a carboxy group.
The amount of the carboxy group introduced into the fine fibrous cellulose is measured, for example, as follows.
First, a slurry containing fine fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, before the treatment with the strongly acidic ion exchange resin, a fibrillation treatment similar to the fibrillation treatment step described later may be performed on the measurement target. Next, a change in electric conductivity is observed while adding an aqueous solution of sodium hydroxide, and a titration curve as shown in FIG. 2 is obtained. In addition, you may implement the defibration process similar to the defibration process process mentioned later with respect to a measurement object as needed. As shown in FIG. 2, the titration curve shows a first region where the increment (slope) of the conductivity becomes substantially constant after the decrease in the electric conductivity, and thereafter, the increment (slope) of the conductivity increases. It is divided into a second area. Note that the boundary point between the first region and the second region is defined as a point at which the amount of change in the conductivity twice (in other words, the increment (slope) of the conductivity becomes maximum). The value obtained by dividing the amount of alkali (mmol) required in the first region of the titration curve by the solid content (g) in the slurry containing fine fibrous cellulose to be titrated is the amount of carboxy group introduced ( mmol / g).

In addition, since the denominator is the mass of the acid-form fine fibrous cellulose, the above-mentioned carboxy group introduction amount (mmol / g) is the amount of carboxy groups (hereinafter referred to as carboxy group amount ( Acid type). On the other hand, when the counter ion of the carboxy group is substituted by an arbitrary cation C so as to have a charge equivalent, the denominator is converted into the mass of the fine fibrous cellulose when the cation C is a counter ion. Thus, the amount of carboxy groups of the fibrous cellulose having the cation C as a counter ion (hereinafter, the amount of carboxy groups (C type)) can be determined.
That is, it is calculated by the following formula.
Carboxy group amount (C type) = Carboxy group amount (acid type) / {1+ (W-1) × (carboxy group amount (acid type)) / 1000}
W: Formula weight per valence of cation C (for example, 23 for Na and 9 for Al)

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

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

  In order to obtain the fine fibrous cellulose into which the ionic substituent is introduced as described above, an ionic substituent introduction step of introducing the ionic substituent into the above-mentioned cellulose-containing fiber material, a washing step, and an alkali treatment step ( It is preferable to have a neutralization step) and a fibrillation treatment step in this order, and may have an acid treatment step instead of or in addition to the washing step. Examples of the ionic substituent introduction step include a phosphate group introduction step and a carboxy group introduction step. Hereinafter, each will be described.

(Ionic substituent introduction step)
(Phosphate group introduction step)
The step of introducing a phosphate group into cellulose fibers (phosphate group introduction step) will be described below.
In the phosphate group introduction step, at least one compound selected from compounds capable of introducing a phosphate group (hereinafter, also referred to as “compound A”) by reacting with a hydroxyl group of a fiber material containing cellulose is converted into cellulose. This is a step of acting on the contained fiber raw material. By this step, a phosphate group-introduced fiber is obtained.

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

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

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

  The amount of compound A added to the fiber raw material is not particularly limited. For example, when the amount of compound A added is converted to the atomic weight of phosphorus, phosphorus is added to the fiber raw material (absolute dry mass, hereinafter also referred to as “absolute dry mass”). The addition amount of atoms is preferably 0.5% by mass or more and 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 the phosphorus atom added to the fiber raw material within the above range, the yield of fine fibrous cellulose can be further improved. On the other hand, by setting the amount of phosphorus atoms added to the fiber raw material to be equal to or less than the above upper limit, the effect of improving the yield and the cost can be balanced. Here, the “absolute dry mass (absolute dry mass)” is the absolute dry mass that has been measured by the method described in ISO 638: 2008 and has reached a constant weight.

The compound B used in this embodiment is at least one selected from urea and its derivatives as described above. Compound B includes, for example, urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like.
From the viewpoint of improving the uniformity of the reaction, the compound B is preferably used as an aqueous solution. From the viewpoint of further improving the uniformity of the reaction, it is preferable to use an aqueous solution in which both the compound A and the compound B are dissolved.
The amount of the compound B to be added to the fiber raw material (absolute dry mass) is not particularly limited, but is, for example, preferably 1% by mass or more and 500% by mass or less, more preferably 10% by mass or more and 400% by mass or less, More preferably, it is 100% by mass or more and 350% by mass or less.

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

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

In the heat treatment according to the present embodiment, for example, compound A is added to a thin sheet-like fiber material by a method such as impregnation or the like, and then the fiber material and the compound A are heated while kneading or stirring with a kneader or the like. Can be adopted. Thereby, it becomes possible to suppress the concentration unevenness of the compound A in the fiber raw material and more uniformly introduce the phosphate group to the surface of the cellulose fiber contained in the fiber raw material. This is because when the water molecules move to the fiber material surface with drying, the dissolved compound A is attracted to the water molecules by the surface tension and moves to the fiber material surface similarly (that is, the concentration unevenness of the compound A decreases). It can be considered that this is caused by the fact that it can be suppressed.
Further, the heating device used for the heat treatment always emits water generated by the dehydration condensation (phosphate esterification) reaction between the compound A and the hydroxyl group contained in cellulose or the like in the fiber raw material, for example, in the system system. It is preferable that the device can be discharged outside. As such a heating device, for example, an air-blowing oven or the like can be mentioned. By constantly discharging the water in the system, it is possible to suppress the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the phosphorylation, and also to suppress the acid hydrolysis of the sugar chains in the fiber. it can. For this reason, it becomes possible to obtain fine fibrous cellulose having a high axial ratio.

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

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

  The amount of phosphate groups introduced into the fiber raw material is, for example, preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.60 mmol / g per 1 g (mass) of fine fibrous cellulose. g or more, more preferably 1.00 mmol / g or more. Further, the amount of the phosphate group introduced into the fiber raw material is, for example, preferably 5.20 mmol / g or less, more preferably 3.65 mmol / g or less, per 1 g (mass) of fine fibrous cellulose. More preferably, it is not more than 00 mmol / g. By setting the amount of the phosphoric acid group to be in the above range, the fineness of the fiber raw material can be easily made, and the stability of the fine fibrous cellulose can be increased.

(Carboxy group introduction step)
The carboxy group introduction step has a compound having a carboxylic acid-derived group or a derivative thereof, or a carboxylic acid-derived group, or a carboxylic acid-derived compound or a carboxylic acid-derived group, for a fiber raw material containing cellulose, such as ozone oxidation or oxidation by the Fenton method, or TEMPO oxidation treatment. It is carried out by treating with an acid anhydride of a compound or a derivative thereof.

Examples of the compound having a group derived from a carboxylic acid include, but are not limited to, dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid, and itaconic acid, and citric acid and aconitic acid. Tricarboxylic acid compounds. Examples of the derivative of the compound having a group derived from a carboxylic acid include, but are not particularly limited to, an imidized product of an acid anhydride of a compound having a carboxy group and a derivative of an acid anhydride of a compound having a carboxy group. The imidized product of the acid anhydride of the compound having a carboxy group is not particularly limited, and examples thereof include imidized products of dicarboxylic acid compounds such as maleimide, succinimide and phthalic imide.
Examples of the acid anhydride of the compound having a group derived from a carboxylic acid include, but are not limited to, maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and dicarboxylic acid compounds such as itaconic anhydride. Acid anhydrides. Examples of the acid anhydride derivative of the compound having a group derived from a carboxylic acid include, but are not particularly limited to, a compound having a carboxy group such as dimethylmaleic anhydride, diethylmaleic anhydride, and diphenylmaleic anhydride. An acid anhydride in which at least a part of hydrogen atoms are substituted with a substituent such as an alkyl group or a phenyl group is exemplified.

In the case where TEMPO oxidation treatment is performed in the carboxy group introduction step, it is preferable that the treatment be performed, for example, at a pH of 6 to 8. Such a process is also called a neutral TEMPO oxidation process. The neutral TEMPO oxidation treatment is performed, for example, by adding pulp as a fiber raw material to a sodium phosphate buffer (pH = 6.8) and TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) as a catalyst. It can be performed by adding nitroxy radical and sodium hypochlorite as a sacrificial reagent. Further, by coexisting sodium chlorite, aldehydes generated in the course of oxidation can be efficiently oxidized to carboxy groups.
Further, the TEMPO oxidation treatment may be performed under the condition that the pH is 10 or more and 11 or less. Such a treatment is also called an alkaline TEMPO oxidation treatment. The alkali TEMPO oxidation treatment can be performed, for example, by adding a nitroxy radical such as TEMPO as a catalyst, sodium bromide as a cocatalyst, and sodium hypochlorite as an oxidizing agent to pulp as a fiber raw material. .

  The amount of the carboxy group introduced into the fiber raw material varies depending on the type of the substituent. For example, when the carboxy group is introduced by TEMPO oxidation, the amount is preferably 0.10 mmol / g or more per 1 g (mass) of fine fibrous cellulose. , 0.20 mmol / g or more, more preferably 0.60 mmol / g or more, particularly preferably 0.90 mmol / g or more. Further, it is preferably at most 2.5 mmol / g, more preferably at most 2.20 mmol / g, even more preferably at most 2.00 mmol / g. In addition, when the substituent is a carboxymethyl group, it may be 5.8 mmol / g or less per 1 g (mass) of fine fibrous cellulose.

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

(Alkali treatment step)
In the case of producing fine fibrous cellulose, the fiber raw material may be subjected to an alkali treatment between a step of introducing a substituent such as an ionic substituent and a defibrating step described below. The method of the alkali treatment is not particularly limited, and includes, for example, a method of immersing the substituent-introduced fiber in an alkaline solution.
The alkali compound contained in the alkali solution is not particularly limited, and may be an inorganic alkali compound or an organic alkali compound. In the present embodiment, it is preferable to use, for example, sodium hydroxide or potassium hydroxide as the alkali compound because of high versatility. The solvent contained in the alkaline solution may be either water or an organic solvent. Among them, the solvent contained in the alkaline solution is preferably a polar solvent containing water or a polar organic solvent exemplified by alcohol, and more preferably an aqueous solvent containing at least water. As the alkali solution, for example, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is preferable because of high versatility.

  The temperature of the alkali solution in the alkali treatment step is not particularly limited, but is preferably, for example, 5 ° C or more and 80 ° C or less, and more preferably 10 ° C or more and 60 ° C or less. The immersion time of the substituent-introduced fibers in the alkali solution in the alkali treatment step is not particularly limited, but is, for example, preferably 5 minutes to 30 minutes, more preferably 10 minutes to 20 minutes. The amount of the alkali solution used in the alkali treatment is not particularly limited. For example, the amount is preferably 100% by mass or more and 100000% by mass or less, and more preferably 1000% by mass or more and 10,000% by mass or less based on the absolute dry mass of the substituent-introduced fiber. More preferably, there is.

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

(Acid treatment step)
In the case of producing fine fibrous cellulose, an acid treatment may be performed on the fiber raw material between the step of introducing a substituent such as an ionic substituent and the defibration step described below. For example, a substituent introduction step, an acid treatment, an alkali treatment, and a fibrillation treatment may be performed in this order.
The method of the acid treatment is not particularly limited, and includes, for example, a method of immersing the fiber raw material in an acid-containing acid solution. The concentration of the acidic solution used is not particularly limited, but is preferably, for example, 10% by mass or less, more preferably 5% by mass or less. The pH of the acidic solution used is not particularly limited, but is preferably, for example, 0 or more and 4 or less, and more preferably 1 or more and 3 or less. As the acid contained in the acidic liquid, for example, an inorganic acid, a sulfonic acid, a carboxylic acid and the like can be used. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, phosphoric acid, boric acid and the like. Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid. 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, for example, preferably from 5 ° C to 100 ° C, and more preferably from 20 ° C to 90 ° C. The immersion time in the acid solution in the acid treatment is not particularly limited, but is preferably, for example, 5 minutes or more and 120 minutes or less, and more preferably 10 minutes or more and 60 minutes or less. The amount of the acid solution used in the acid treatment is not particularly limited. For example, the amount is preferably from 100% by mass to 100,000% by mass, and more preferably from 1,000% by mass to 10,000% by mass, based on the absolute dry mass of the fiber raw material. Is more preferred.

(Fibrillation processing)
Fine fibrous cellulose can be obtained by defibrating a fiber having a substituent introduced therein, such as an ionic substituent, in a defibrating step.
In the defibrating process, for example, a defibrating device can be used. Examples of the defibrating apparatus include, but are not limited to, a high-speed defibrating machine, a grinder (stone mill-type crusher), a high-pressure homogenizer or an ultra-high-pressure homogenizer, a high-pressure collision-type crusher, a ball mill, a bead mill, a disk-type refiner, a conical refiner, A kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, a beater, or the like can be used. Among the above defibration apparatuses, it is more preferable to use a high-speed defibrator, a high-pressure homogenizer, or an ultra-high-pressure homogenizer, which is less affected by the pulverized media and is less likely to cause contamination.

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

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

<Oxo acid containing chlorine or its salt>
The fine fibrous cellulose-containing composition of the present invention contains oxo acid containing chlorine or a salt thereof.
Examples of the oxo acid containing chlorine include hypochlorous acid, chlorous acid, chloric acid, and perchloric acid, and hypochlorous acid is preferable from the viewpoint of availability and stability.
Examples of oxoacid salts containing chlorine include salts of hypochlorous acid such as sodium hypochlorite, potassium hypochlorite, calcium hypochlorite; sodium chlorite, potassium chlorite, and chlorine hypochlorite. Salts of chlorite such as copper oxychloride and barium chlorite; chlorates such as sodium chlorate, potassium chlorate, ammonium chlorate, calcium chlorate, barium chlorate, zinc chlorate and silver chlorate; perchlorine Perchlorates such as ammonium acid, potassium perchlorate, sodium perchlorate, calcium perchlorate, silver chlorite, and magnesium perchlorate are obtained.
Among them, as the oxo acid containing chlorine or a salt thereof, it is preferable to contain a salt of oxo acid containing chlorine, more preferably a salt of hypochlorous acid, and sodium hypochlorite, More preferably, it contains at least one selected from the group consisting of potassium chlorate and calcium hypochlorite, and at least one selected from the group consisting of sodium hypochlorite and potassium hypochlorite. It is particularly preferred to contain it, and most preferably it contains sodium hypochlorite.

In the fine fibrous cellulose-containing composition of the present invention, the content of oxo acid or a salt thereof containing chlorine relative to 100 parts by mass of the fine fibrous cellulose is 0.0001 to 10 parts by mass. When the content of chlorine-containing oxo acid or a salt thereof is less than 0.0001 part by mass, a sufficient viscosity lowering effect cannot be obtained, and the content of chlorine-containing oxo acid or a salt thereof is 10 parts by mass. If it exceeds, the fine fibrous cellulose-containing composition tends to yellow.
The content of oxo acid or a salt thereof containing chlorine relative to 100 parts by mass of fine fibrous cellulose is preferably 0.0003 parts by mass or more, more preferably 0.001 or more, still more preferably 0.003 parts by mass or more, It is preferably at least 0.005 parts by mass, more preferably at least 0.01 parts by mass, preferably at most 3 parts by mass, more preferably at most 2 parts by mass, further preferably at most 1 part by mass.
In the oxidation treatment of the cellulose raw material, using an oxo acid or a salt thereof containing chlorine as an oxidizing agent, and then, after performing a water washing step, when performing a water washing step, such as in the case of performing a fibrillation treatment, The content of oxo acid or a salt thereof containing chlorine is less than 0.0001 part by mass with respect to 100 parts by mass of the fine fibrous cellulose.

<Fine fibrous cellulose-containing composition>
In the present invention, the fine fibrous cellulose-containing composition may contain other components other than oxoacid containing fine fibrous cellulose and chlorine or a salt thereof. Other components include, for example, a water-soluble polymer, and a surfactant.
Examples of the water-soluble polymer include carboxyvinyl polymer, polyvinyl alcohol, alkyl methacrylate / acrylic acid copolymer, polyvinylpyrrolidone, sodium polyacrylate, polyethylene glycol, diethylene glycol, triethylene glycol, polyethylene oxide, propylene glycol, dipropylene glycol, Synthetic water-soluble polymers exemplified by polypropylene glycol, isoprene glycol, hexylene glycol, 1,3-butylene glycol, and polyacrylamide; xanthan gum, guar gum, tamarind gum, carrageenan, locust bean gum, quince seed, alginic acid, pullulan , Carrageenan, and thickening polysaccharides exemplified by pectin; carboxymethyl cellulose; Cellulose derivatives such as chilled cellulose and hydroxyethyl cellulose; starches such as cationized starch, raw starch, oxidized starch, etherified starch, esterified starch, and amylose; glycerin, diglycerin, and Glycerin exemplified by polyglycerin; hyaluronic acid; metal salts of hyaluronic acid; and the like.
The content of the water-soluble polymer in the fine fibrous cellulose-containing composition is, for example, preferably at least 0.05 part by mass, and more preferably at least 0.1 part by mass with respect to 100 parts by mass of the fine fibrous cellulose. It is more preferable that the amount be 0.5 parts by mass or more. On the other hand, the content of the water-soluble polymer in the fine fibrous cellulose-containing composition is, for example, preferably 500 parts by mass or less, and more preferably 200 parts by mass or less with respect to 100 parts by mass of the fine fibrous cellulose. Is more preferable, and the content is more preferably 100 parts by mass or less. By setting the content of the water-soluble polymer in the above range, both the properties of the fine fibrous cellulose and the properties of the water-soluble polymer can be exhibited.

As the surfactant, a nonionic surfactant, an anionic surfactant, a cationic surfactant, or an amphoteric surfactant can be used. Nonionic surfactants include, for example, polyoxyalkylene alkyl ethers, polyglycerin fatty acid esters, glycerin monofatty acid esters, glycerin difatty acid esters, pluronics, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sucrose fatty acid esters, Oxyethylene acyl ester, alkyl polyglycoside, fatty acid methyl glycoside ester, alkyl methyl glucamide, fatty acid alkanolamide and the like can be mentioned. Examples of the anionic surfactant include sodium oleate, potassium oleate, sodium laurate, sodium todecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, and polyoxyethylene. Examples thereof include sodium ethylene alkyl allyl ether sulfate, sodium polyoxyethylene dialkyl sulfate, polyoxyethylene alkyl ether phosphate, and polyoxyethylene alkyl allyl ether phosphate. Examples of the cationic surfactant include alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, acylaminoethyldiethylammonium salt, acylaminoethyldiethylamine salt, alkylamidopropyldimethylbenzylammonium salt, and alkylpyridinium salt. Quaternary ammonium salts such as alkylpyridinium sulfate, stearamidomethylpyridinium salt, alkylquinolinium salt, alkylisoquinolinium salt, fatty acid polyethylene polyamide, acylaminoethylpyridinium salt, acylcholaminoformylmethylpyridinium salt, Stearooxymethylpyridinium salt, fatty acid triethanolamine, fatty acid triethanolamine formate, trioxyethylene Ester-linked amines such as fatty acid triethanolamine, cetyloxymethylpyridinium salt, p-isooctylphenoxyethoxyethyldimethylbenzylammonium salt and ether-bonded quaternary ammonium salts, alkylimidazoline, 1-hydroxyethyl-2-alkylimidazoline, 1 -Acetylaminoethyl-2-alkylimidazoline, heteroalkylamine such as 2-alkyl-4-methyl-4-hydroxymethyloxazoline, polyoxyethylene alkylamine, N-alkylpropylenediamine, N-alkylpolyethylenepolyamine, N-alkyl Examples thereof include amine derivatives such as polyethylene polyamine dimethyl sulfate, alkyl biguanide, and long chain amine oxide. Examples of the amphoteric surfactant include betaine lauryl dimethylaminoacetate, cocamidopropyl betaine, lauramidopropyl betaine, and sodium cocoamphoacetate.
The content of the surfactant in the fine fibrous cellulose-containing composition is, for example, preferably at least 0.01 part by mass, and more preferably at least 0.05 part by mass with respect to 100 parts by mass of the fine fibrous cellulose. Is more preferable, and the content is more preferably 0.1 part by mass or more. On the other hand, the content of the surfactant in the fine fibrous cellulose-containing composition is, for example, preferably 5 parts by mass or less, and more preferably 3 parts by mass or less based on 100 parts by mass of the fine fibrous cellulose. More preferably, it is even more preferably 2 parts by mass or less. By setting the content of the surfactant within the above range, both the properties of the fine fibrous cellulose and the properties of the surfactant can be exhibited.
The fine fibrous cellulose-containing composition is, for example, an organic ion, a coupling agent, an inorganic stratiform compound, an inorganic compound, a leveling agent, a preservative, and a defoaming agent, in addition to the fine fibrous cellulose, the water-soluble polymer, and the surfactant. One or more selected from organic particles, lubricants, antistatic agents, ultraviolet protective agents, dyes, pigments, stabilizers, magnetic powders, alignment promoters, plasticizers, dispersants, and crosslinking agents May be included.

  The fibrous cellulose-containing material may contain a solvent. The solvent can include, for example, one or both of water and an organic solvent. Examples of the organic solvent include alcohols, polyhydric alcohols, ketones, ethers, esters, hydrocarbons, halogens, and aprotic polar solvents. 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 ketones include acetone and methyl ethyl ketone (MEK). Examples of the ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and propylene glycol monomethyl ether. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the hydrocarbons include n-hexane, toluene, xylene and the like. Examples of the halogens include methylene chloride, trichloroethylene, chloroform and the like. Examples of the aprotic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methyl-2-pyrrolidinone (NMP).

Haze of a slurry obtained by adjusting the solid content concentration of the fine fibrous cellulose-containing composition to 0.2% by mass of the fine fibrous cellulose-containing composition at 23 ° C. using a glass cell having an optical path length of 1 cm in accordance with JIS K 7136. Is preferably 2.0% or less. Further, the haze is more preferably 1.5% or less, further preferably 1.0% or less. On the other hand, the lower limit of the haze is not particularly limited, and may be, for example, 0%. By setting the haze of the slurry of the fine fibrous cellulose-containing composition in such a range, a sheet or the like having higher transparency can be formed.
In the present embodiment, the measurement can be performed using, for example, a haze meter (HM-150, manufactured by Murakami Color Research Laboratory). In addition, as the glass cell having an optical path length of 1 cm, for example, a liquid glass cell having an optical path length of 1 cm (MG-40, manufactured by Fujiwara Seisakusho, reverse optical path) can be used. The zero point measurement is performed using ion-exchanged water placed in the glass cell.
The solvent at the time of the above haze measurement preferably contains at least water, and the content of water in the entire solvent is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass. % Or more, particularly preferably 95% by mass or more, and may be 100% by mass.

In the present invention, the fine fibrous cellulose-containing composition was measured using a glass cell having an optical path length of 1 cm in accordance with JIS K 7361 of a slurry in which the solid content concentration of the fine fibrous cellulose was adjusted to 0.2% by mass. The total light transmittance is preferably 90% or more. Further, the total light transmittance is more preferably 93% or more, further preferably 95% or more. On the other hand, the upper limit value of the total light transmittance is not particularly limited, and may be, for example, 100%. By setting the total light transmittance of the slurry of the fine fibrous cellulose-containing composition in such a range, a sheet or the like having higher transparency can be formed.
In the present embodiment, the total light transmittance can be measured by using, for example, a haze meter (HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.). In addition, as the glass cell having an optical path length of 1 cm, for example, a liquid glass cell having an optical path length of 1 cm (MG-40, manufactured by Fujiwara Seisakusho, reverse optical path) can be used. The zero point measurement is performed using ion-exchanged water placed in the glass cell.
The solvent at the time of measuring the total light transmittance preferably contains at least water, and the content of water in the entire solvent is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably. Is 90% by mass or more, particularly preferably 95% by mass or more, and may be 100% by mass.

The viscosity of the slurry obtained by adjusting the fine fibrous cellulose-containing composition to a solid concentration of 0.4% by mass of the fine fibrous cellulose at 23 ° C. using a B-type viscometer at a rotation speed of 3 rpm is preferably 1.0 × 10 ⁴ mPa · s or less, more preferably 8.5 × 10 ³ mPa · s or less, still more preferably 7.0 × 10 ³ mPa · s or less. The lower limit of the viscosity is not particularly limited, but is preferably 1.0 × 10 ³ mPa · s or more, more preferably 1.5 × 10 ³ mPa · s or more.
Here, for the measurement of the viscosity, for example, a B-type viscometer (manufactured by BLOOKFIELD, analog viscometer T-LVT) can be used. The measurement conditions were as follows: the fine fibrous cellulose-containing composition was diluted so that the solid content concentration of the fine fibrous cellulose was 0.4% by mass, and stirred with a disperser at, for example, 1500 rpm for 5 minutes. Let stand for 24 hours in an environment with a relative humidity of 50%. Thereafter, for example, at a liquid temperature of 23 ° C., the rotational speed of the viscometer is measured at 3 rpm, and the viscosity value at 3 minutes from the start of the measurement is defined as the viscosity of the dispersion.
The solvent at the time of the viscosity measurement preferably contains at least water, and the content of water in the entire solvent is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass. % Or more, particularly preferably 95% by mass or more, and may be 100% by mass.

The form of the fine fibrous cellulose-containing composition is not particularly limited, and examples thereof include a liquid such as a slurry, a solid such as a granular powder, and a gel.
(Slurry)
When the fine fibrous cellulose-containing composition is a slurry, the content of fine fibrous cellulose contained in the fine fibrous cellulose-containing composition is 0.1% by mass based on the total mass of the fine fibrous cellulose-containing composition. The content is preferably from 5.0 to 5.0% by mass, more preferably from 0.3 to 3.0% by mass, and still more preferably from 0.5 to 3.0% by mass. . When the content of the fine fibrous cellulose is in the above range, the characteristics of the fine fibrous cellulose are easily exhibited.
When the fine fibrous cellulose-containing composition is a slurry, and the solvent contained in the fine fibrous cellulose-containing composition is water, the content of the solvent is preferably based on the total mass of the fine fibrous cellulose-containing material. It is 60% by mass or more, more preferably 90% by mass or more, still more preferably 97% by mass or more, and preferably 99.9% by mass or less, more preferably 99.7% by mass or less, and still more preferably 99.5% by mass. % Or less. By setting the content of the solvent within the above range, a suitable viscosity can be obtained.

(Solid or gel)
When the fine fibrous cellulose-containing composition is a solid or a gel, the content of the fine fibrous cellulose contained in the fine fibrous cellulose-containing composition is, for example, based on the total mass of the fine fibrous cellulose-containing composition. On the other hand, the content is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and particularly preferably 20% by mass or more. When the fine fibrous cellulose-containing composition is a solid or a gel, the upper limit of the content of fine fibrous cellulose contained in the fine fibrous cellulose-containing composition is not particularly limited. 0.5% by mass. By setting the content of the fine fibrous cellulose in the above range, a fine fibrous cellulose-containing composition having more excellent handling properties can be obtained.

When the fine fibrous cellulose-containing composition is a solid or a gel, the content of the solvent contained in the fine fibrous cellulose-containing composition is, for example, 90 to the total mass of the fine fibrous cellulose-containing composition. It is preferably at most 85 mass%, more preferably at most 80 mass%, even more preferably at most 70 mass%. By setting the upper limit of the content of the solvent in the above range, a fine fibrous cellulose-containing composition having excellent handling properties can be obtained. On the other hand, the lower limit of the content of the solvent contained in the fine fibrous cellulose-containing composition is not particularly limited, and may be, for example, 0% by mass. In the present embodiment, the content of the solvent contained in the fine fibrous cellulose-containing composition can be, for example, 0.5% by mass or more based on the total mass of the fine fibrous cellulose-containing composition.
When the fine fibrous cellulose-containing composition is a solid or a gel, the fine fibrous cellulose-containing composition may contain, for example, a concentrating agent used in a concentration step described below. For example, when the concentrating agent is a metal component, the content of the metal component in the fine fibrous cellulose-containing composition is preferably 1.0% by mass or less, more preferably 0.3% by mass or less. , 0.15% by mass or less, particularly preferably 0.1% by mass or less. When the concentrating agent is a metal component, the lower limit of the content of the metal component in the fine fibrous cellulose-containing composition is not particularly limited, but may be, for example, 0.0001% by mass. By setting the content of the metal component in the above range, a fine fibrous cellulose-containing composition having excellent redispersibility in a predetermined dispersion medium such as water can be obtained.

  When the fine fibrous cellulose-containing composition is a granular material, the fine fibrous cellulose-containing material includes one or both of a powder and a granular material. Here, the powdery material is smaller than the granular material. Generally, the powdery material refers to fine particles having a particle diameter of 1 nm or more and less than 0.1 mm. Further, the granular material refers to particles having a particle diameter of 0.1 mm or more and 10 mm or less. The particle size of the powder can be measured and calculated using, for example, a laser diffraction method. The measurement by the laser diffraction method can be performed by using, for example, a laser diffraction scattering type particle size distribution measuring apparatus (Microtrac 3300EXII, Nikkiso Co., Ltd.).

  The fine fibrous cellulose-containing composition in the form of a solid or a gel can be used as a redispersion slurry redispersed in a solvent such as water. The type of solvent used to obtain such a redispersed slurry is not particularly limited, and examples thereof include water, an organic solvent, and a mixture of water and an organic solvent. Examples of the organic solvent include alcohols, polyhydric alcohols, ketones, ethers, esters, hydrocarbons, halogens, and aprotic polar solvents. 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 ketones include acetone and methyl ethyl ketone (MEK). Examples of the ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and propylene glycol monomethyl ether. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the hydrocarbons include n-hexane, toluene, xylene and the like. Examples of the halogens include methylene chloride, trichloroethylene, chloroform and the like. Examples of the aprotic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methyl-2-pyrrolidinone (NMP).

(Sheet form)
In the present invention, the fine fibrous cellulose-containing composition may be in the form of a sheet.
In the present embodiment, for example, a sheet can be obtained by performing a sheet forming step described below using the fine fibrous cellulose-containing composition which is the above-mentioned liquid material.
The content of the fine fibrous cellulose in the sheet is, for example, preferably 0.5% by mass or more, more preferably 1% by mass or more, and more preferably 5% by mass or more based on the total mass of the sheet. More preferably, it is particularly preferably at least 10% by mass. On the other hand, the upper limit of the content of the fine fibrous cellulose in the sheet is not particularly limited, and may be 100% by mass or 95% by mass with respect to the total mass of the sheet.
From the viewpoint of obtaining a sheet having particularly excellent mechanical strength, the content of fine fibrous cellulose in the sheet is preferably, for example, 60% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass. %, More preferably 90% by mass or more, and particularly preferably 90% by mass or more.
In addition, from the viewpoint of including a large amount of another material such as a water-soluble polymer in the sheet, the content of the fine fibrous cellulose in the sheet is preferably, for example, 50% by mass or less.

The sheet may include, for example, a water-soluble polymer. Thereby, the transparency and mechanical strength of the sheet can be further improved. As the water-soluble polymer, for example, those described above can be used.
The content of the water-soluble polymer in the sheet is, for example, preferably 1% by mass or more, more preferably 5% by mass or more, and more preferably 10% by mass or more based on the total mass of the sheet. More preferred. Thereby, a sheet excellent in transparency and mechanical properties can be obtained. On the other hand, the content of the water-soluble polymer in the sheet is, for example, preferably 99.5% by mass or less, more preferably 95% by mass or less based on the total mass of the sheet.

The sheet is made of fine fibrous cellulose, oxo acid containing chlorine or a salt thereof, and a water-soluble polymer, for example, a surfactant, an organic ion, a coupling agent, an inorganic layered compound, an inorganic compound, a leveling agent, and a preservative. , One selected from defoaming agents, organic particles, lubricants, antistatic agents, ultraviolet protection agents, dyes, pigments, stabilizers, magnetic powders, alignment promoters, plasticizers, dispersants, and crosslinkers Two or more types may be included.
The sheet may include a solvent. As the solvent, for example, those described above can be used.
The content of the solvent in the sheet is, for example, preferably 0.5% by mass or more, more preferably 1% by mass or more, and more preferably 5% by mass or more based on the total mass of the sheet. preferable. Thereby, flexibility can be given to the sheet. On the other hand, the content of the solvent in the sheet is, for example, preferably 25% by mass or less, more preferably 15% by mass or less, based on the total mass of the sheet. Thereby, a sheet having good flexibility can be obtained.
The water content in the sheet can be calculated, for example, by the following procedure. First, a 100 mm square sheet is conditioned for 24 hours at a temperature of 23 ° C. and a relative humidity of 50%, and then the mass W ₀ of the sheet is measured. Then, after the sheet is dried for 16 hours at 105 ° C. in a constant temperature dryer, measuring the mass W ₁ of the sheet. From the measured mass, the content of the solvent in the sheet is calculated according to the following equation (1).
Water content in sheet = 100 × (1−W ₁ / W ₀ ) Equation (1)

The tensile modulus of the sheet is, for example, preferably 2.5 GPa or more, more preferably 3.0 GPa or more, and even more preferably 3.5 GPa or more. The upper limit of the tensile modulus of the sheet is not particularly limited, but may be, for example, 50 GPa or less.
Here, the tensile modulus of the sheet is a value measured using a tensile tester Tensilon (manufactured by A & D) in accordance with, for example, JIS P 8113. When measuring the tensile elasticity, a specimen conditioned at 23 ° C. and a relative humidity of 50% for 24 hours is used as a test specimen for measurement, and the measurement is performed at 23 ° C. and a relative humidity of 50%.
The haze of the sheet is, for example, preferably 2% or less, more preferably 1.5% or less, and still more preferably 1% or less. On the other hand, the lower limit of the haze of the sheet is not particularly limited, and may be, for example, 0%. Here, the haze of the sheet is a value measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.) according to, for example, JIS K 7136.
The total light transmittance of the sheet is, for example, preferably 85% or more, more preferably 90% or more, and still more preferably 91% or more. On the other hand, the upper limit value of the total light transmittance of the sheet is not particularly limited, and may be, for example, 100%. Here, the total light transmittance of the sheet is a value measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with, for example, JIS K7361.

The thickness of the sheet is not particularly limited, but is, for example, preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. The upper limit of the sheet thickness is not particularly limited, but may be, for example, 1000 μm. The thickness of the sheet can be measured, for example, with a stylus-type thickness gauge (Millitron 1202D, manufactured by Marl).
The basis weight of the sheet is not particularly limited, but is preferably, for example, 10 g / m ² or more, more preferably 20 g / m ² or more, and further preferably 30 g / m ² or more. The basis weight of the sheet is not particularly limited, but is preferably, for example, 100 g / m ² or less, and more preferably 80 g / m ² or less. Here, the basis weight of the sheet can be calculated based on, for example, JIS P8124.
The density of the sheet is not particularly limited, but is preferably, for example, 0.1 g / cm ³ or more, more preferably 0.5 g / cm ³ or more, and further preferably 1.0 g / cm ³ or more. preferable. The density of the sheet is not particularly limited, but is, for example, preferably 5.0 g / cm ³ or less, and more preferably 3.0 g / cm ³ or less. Here, the sheet density can be calculated by measuring the thickness and mass of a 50 mm square sheet after conditioning the sheet under a condition of 23 ° C. and 50% RH for 24 hours.

[Method for producing fine fibrous cellulose-containing composition]
In the present invention, the above-mentioned fine fibrous cellulose is preferably produced by a method having the following steps 1 and 2 in this order.
Step 1: fibrillated cellulose in a solvent is fibrillated to obtain a dispersion containing fine fibrous cellulose. Step 2: oxo acid containing chlorine or a salt thereof is added to the dispersion containing fine fibrous cellulose. Step of addition In the present invention, the amount of the oxo acid or salt thereof containing chlorine to be added in step 2 is 0.0001 to 10 parts by mass with respect to 100 parts by mass of the fine fibrous cellulose. .
Here, the step of obtaining the dispersion containing fine fibrous cellulose in the step 1 is performed by introducing an ionic substituent into the fiber material containing cellulose as described in the method for producing fine fibrous cellulose. It is preferable to have an introduction step, a washing step, an alkali treatment step (neutralization step), and a defibration treatment step in this order, and even if it has an acid treatment step instead of or in addition to the washing step. Good. Examples of the ionic substituent introduction step include a phosphate group introduction step and a carboxy group introduction step. Therefore, in the present invention, the fine fibrous cellulose in the dispersion containing the fine fibrous cellulose obtained in Step 1 preferably has an ionic substituent.

In step 2, oxo acid containing chlorine or a salt thereof is added to the dispersion containing fine fibrous cellulose. The method of addition is not particularly limited, but the oxo acid containing chlorine or a salt thereof is added so that the addition amount is 0.0001 to 10 parts by mass with respect to 100 parts by mass of the fine fibrous cellulose.
The oxo acid or its salt containing chlorine is preferably added with stirring so that the oxo acid or its salt containing chlorine at a high concentration does not exist in the dispersion.

  The fibrous cellulose-containing composition of the present invention can be used for various uses, for example, as a thickener. Further, it can be used as a reinforcing material by mixing with a resin or an emulsion, or various sheets may be produced by forming a film using a slurry of the fine fibrous cellulose-containing composition. The sheet is suitable for use in light-transmitting substrates such as various display devices and various solar cells. In addition, it is suitable for use as substrates of electronic devices, members of home appliances, window materials of various vehicles and buildings, interior materials, exterior materials, packaging materials, and the like. Further, it is suitable for use in which the sheet itself is used as a reinforcing material, in addition to yarns, filters, fabrics, cushioning materials, sponges, abrasives, and the like.

  Hereinafter, features of the present invention will be described more specifically with reference to examples and comparative examples. Materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples described below.

<Production Example 1>
As a raw material pulp, a softwood kraft pulp made by Oji Paper (solid content: 93% by mass, basis weight: 208 g / m ^2, sheeted; 700 mL of Canadian Standard Freeness (CSF) measured by disintegration and measured according to JIS P 8121) It was used. This raw material pulp was subjected to a phosphorylation treatment as follows. First, a mixed aqueous solution of ammonium dihydrogen phosphate and urea is added to 100 parts by mass (absolute dry mass) of the raw material pulp to obtain 45 parts by mass of ammonium dihydrogen phosphate, 120 parts by mass of urea, and 150 parts by mass of water. To obtain a chemical-impregnated pulp. Next, the obtained chemical impregnated pulp was heated with a hot air drier at 165 ° C. for 200 seconds to introduce a phosphate group into cellulose in the pulp to obtain a phosphorylated pulp.

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

  Next, the washed phosphorylated pulp was subjected to an alkali treatment (neutralization treatment) as follows. First, a phosphorylated pulp slurry having a pH of 12 or more and 13 or less was obtained by diluting the washed phosphorylated pulp with 10 L of ion-exchanged water and then gradually adding a 1N aqueous sodium hydroxide solution with stirring. . Next, the phosphorylated pulp slurry was dehydrated to obtain a phosphorylated pulp subjected to an alkali treatment (neutralization treatment).

Next, the above-mentioned washing treatment was performed on the phosphorylated pulp after the neutralization treatment. The infrared absorption spectrum of the phosphorylated pulp thus obtained was measured using FT-IR. As a result, absorption based on a phosphate group was observed at around 1230 cm ⁻¹ , confirming that a phosphate group was added to the pulp. Further, the obtained phosphorylated pulp was tested and analyzed by an X-ray diffractometer. As a result, it was found that two points, 2θ = around 14 ° to 17 ° and 2θ = around 22 ° to 23 °, were located at two positions. A typical peak was confirmed, and it was confirmed to have cellulose type I crystals.

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

X-ray diffraction confirmed that the fine fibrous cellulose maintained cellulose type I crystals.
Moreover, when the fiber width of the fine fibrous cellulose was measured using a transmission electron microscope, it was 3 to 5 nm. In addition, the amount of phosphate groups (the amount of strongly acidic groups) measured by the measurement method described later was 1.45 mmol / g.

(Measurement of phosphate group content)
The phosphate group content of the fine fibrous cellulose is obtained by diluting a fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion-exchanged water so that the content becomes 0.2% by mass. After the treatment with the ion-exchange resin was performed on the cellulose-containing slurry, the measurement was performed by performing titration using an alkali.
In the treatment with the ion-exchange resin, 1/10 by volume of a strongly acidic ion-exchange resin (Amberjet 1024; manufactured by Organo Co., Ltd., conditioned) was added to the fine fibrous cellulose-containing slurry, followed by shaking for 1 hour. Thereafter, the mixture was poured on a mesh having a mesh size of 90 μm to separate the resin and the slurry.
In addition, titration using an alkali is performed by adding 50 μL of a 0.1N aqueous sodium hydroxide solution once every 30 seconds to a slurry containing fine fibrous cellulose after treatment with an ion-exchange resin while the electric conductivity of the slurry is shown. This was done by measuring the change in the degree value. The amount of phosphoric acid groups (mmol / g) is obtained by dividing the amount of alkali (mmol) required in a region corresponding to the first region shown in FIG. 1 in the measurement results by the solid content (g) in the slurry to be titrated. Was calculated.

<Production Example 2>
As the raw material pulp, softwood kraft pulp (undried) manufactured by Oji Paper Co., Ltd. was used. This raw material pulp was subjected to an alkali TEMPO oxidation treatment as follows.
First, the raw pulp equivalent to 100 parts by mass of dry mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), 10 parts by mass of sodium bromide, and 10,000 parts by mass of water Parts. Next, a 13% by mass aqueous sodium hypochlorite solution was added to 3.8 g of 1.0 g of pulp to start the reaction. During the reaction, a 0.5 M aqueous sodium hydroxide solution was added dropwise to keep the pH at 10 to 10.5, and the reaction was considered completed when no change in pH was observed.

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

  This dehydrated sheet was subjected to additional oxidation treatment of the remaining aldehyde groups as follows. The dehydrated sheet equivalent to 100 parts by mass of dry mass was dispersed in 10,000 parts by mass of 0.1 mol / L acetate buffer (pH 4.8). Next, 113 parts by mass of 80% sodium chlorite was added, and the mixture was immediately sealed and reacted at room temperature for 48 hours while stirring at 500 rpm using a magnetic stirrer to obtain a pulp slurry.

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

  With respect to the TEMPO oxidized pulp thus obtained, the amount of carboxy groups measured by a measurement method described later was 1.30 mmol / g.

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

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

X-ray diffraction confirmed that the fine fibrous cellulose maintained cellulose type I crystals.
Moreover, when the fiber width of the fine fibrous cellulose was measured using a transmission electron microscope, it was 3 to 5 nm. In addition, the amount of carboxy groups measured by the measurement method described later was 1.30 mmol / g.

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

<Example 1>
100 g of the fine fibrous cellulose dispersion liquid (A) (2% by mass) was taken, and a sodium hypochlorite solution having an effective chlorine concentration of 12% was diluted 100 times with ion-exchanged water, and then 0.17 g was collected. After adding to the fine fibrous cellulose, the mixture was stirred. Thus, a composition containing fine fibrous cellulose and 0.01 parts by mass of sodium hypochlorite per 100 parts by mass of fine fibrous cellulose was obtained.

<Example 2>
In Example 1, a sodium hypochlorite solution having an effective chlorine concentration of 12% was diluted 100 times with ion-exchanged water, and the amount added was changed to 2.5 g. Otherwise, the test was performed in the same manner as in Example 1.

<Example 3>
In Example 1, the sodium hypochlorite solution having an effective chlorine concentration of 12% was not diluted, and the amount added was changed to 0.17 g. Otherwise, the test was performed in the same manner as in Example 1.

<Example 4>
In Example 2, potassium hypochlorite having an effective chlorine concentration of 12% was used instead of sodium hypochlorite having an effective chlorine concentration of 12%. Otherwise, the test was performed in the same manner as in Example 2.

<Example 5>
In Example 2, the fine fibrous cellulose dispersion (B) produced from TEMPO oxidized pulp was used instead of the fine fibrous cellulose dispersion (A) produced from phosphorylated pulp. Otherwise, the test was performed in the same manner as in Example 2.

<Comparative Example 1>
In Example 1, a sodium hypochlorite solution having an effective chlorine concentration of 12% was diluted 100,000 times with ion-exchanged water, and the amount added was changed to 0.17 g. Otherwise, the test was performed in the same manner as in Example 1.

<Comparative Example 2>
In Example 1, the amount of addition was changed to 8.3 g without diluting the sodium hypochlorite solution having an effective chlorine concentration of 12%. Otherwise, the test was performed in the same manner as in Example 1.

<Comparative Example 3>
In Comparative Example 2, potassium hypochlorite having an effective chlorine concentration of 12% was used instead of sodium hypochlorite having an effective chlorine concentration of 12%. Other than that, all were tested in the same manner as in Comparative Example 2.

<Comparative Example 4>
In Example 1, the sodium hypochlorite solution was not added. Otherwise, the test was performed in the same manner as in Example 1.

<Comparative Example 5>
In Example 5, the sodium hypochlorite solution was not added. Otherwise, the test was conducted in the same manner as in Example 5.

(Measurement of fiber width of fine fibrous cellulose)
The fiber width of the fine fibrous cellulose was measured by the following method.
The supernatant liquid of the fine fibrous cellulose dispersion obtained by the treatment with a wet atomizer is mixed with water so that the concentration of the fine fibrous cellulose becomes 0.01% by mass or more and 0.1% by mass or less. The diluted and hydrophilized carbon grid film was dropped. After drying, it was stained with uranyl acetate and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.).

(Measurement of viscosity of fine fibrous cellulose dispersion)
The viscosity of the fine fibrous cellulose dispersion was measured as follows. First, the fine fibrous cellulose dispersion was diluted with ion-exchanged water so that the solid content concentration became 0.4% by mass, and then the mixture was stirred with a disperser at 1500 rpm for 5 minutes. Next, the viscosity of the dispersion liquid thus obtained was measured using a B-type viscometer (manufactured by BLOOKFIELD, analog viscometer T-LVT). The measurement conditions were a rotation speed of 3 rpm, and a viscosity value three minutes after the start of the measurement was defined as the viscosity of the dispersion. The dispersion to be measured was allowed to stand for 24 hours in an environment at 23 ° C. and 50% relative humidity before the measurement. The liquid temperature of the dispersion at the time of measurement was 23 ° C.

(Measurement of specific viscosity and degree of polymerization of cellulose fiber)
The specific viscosity and the degree of polymerization of the cellulose fibers were measured according to Tappi T230. That is, the viscosity (η ₁ (unit: cP)) measured by dispersing the cellulose fiber to be measured in a dispersion medium and the blank viscosity (η ₀ (unit: cP)) measured only by the dispersion medium are used. After the measurement, the specific viscosity (η _sp ) and the intrinsic viscosity ([η] (unit: mL / g)) were measured according to the following formula.
η _sp = (η ₁ / η ₀ ) -1
[Η] = η _sp /(c(1+0.28×η _sp ))
Here, c in the formula indicates the concentration (g / mL) of the cellulose fiber at the time of measuring the viscosity.
Further, the polymerization degree (DP) of the cellulose fiber was calculated from the following equation.
DP = 1.75 × [η]
Since this degree of polymerization is an average degree of polymerization measured by a viscosity method, it is sometimes referred to as “viscosity average degree of polymerization”.

(Measurement of haze of fine fibrous cellulose dispersion)
The haze of the fine fibrous cellulose dispersion was measured by diluting the fine fibrous cellulose dispersion after the fibrillation treatment process to 0.2% by mass with ion-exchanged water, stirring thoroughly, and then using a haze meter. (HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.) using a liquid glass cell with a light path length of 1 cm (MG-40, manufactured by Fujiwara Seisakusho Co., Ltd., reverse light path) in accordance with JIS K 7136 did.
Note that the zero point measurement was performed with ion-exchanged water placed in the same glass cell. The dispersion to be measured was allowed to stand for 24 hours in an environment at 23 ° C. and 50% relative humidity before the measurement. The liquid temperature of the dispersion at the time of measurement was 23 ° C.

(Confirmation of discoloration of fine fibrous cellulose dispersion)
The 0.4% by mass of the fine fibrous cellulose dispersion was visually observed to check for discoloration.

As shown in the Examples, when focusing on the viscosity, Comparative Example 4, which does not contain oxo acid containing chlorine or a salt thereof, has a viscosity of 11,253 mPa · s, whereas Examples 1 to 4 show about 15 to 80% of the viscosity. It is considered that an appropriate viscosity reduction was realized by a simple operation. On the other hand, the viscosity of Comparative Example 1 is too high, and thus is not suitable in the present invention where the viscosity is to be reduced appropriately. In Comparative Examples 2 and 3, clear yellowing of the sample was observed, impairing the colorless and transparent property of the fine fibrous cellulose composition.
The viscosity of Comparative Example 5 not containing oxo acid containing chlorine or a salt thereof was 19,700 mPa · s, whereas that of Example 5 was about 30% of the viscosity. It is considered that even when fibrous cellulose was used, an appropriate decrease in viscosity could be realized by a simple operation. In addition, since the viscosity of the comparative example 5 is too high, it is not suitable for the present invention in which the viscosity is to be reduced appropriately.
Regarding haze, there is not much difference from Comparative Example 4 in Examples 1 to 4 and Comparative Examples 1 to 3. However, in Comparative Examples 2 and 3, in which the amount of oxo acid containing chlorine or a salt thereof exceeds the range of the present invention, yellowing of the dispersion was observed.

ADVANTAGE OF THE INVENTION According to this invention, the fine fibrous cellulose composition easily and precisely adjusted to arbitrary viscosity can be provided. In order to adjust the viscosity of the fine fibrous cellulose, a conventional method requires a defibration treatment using a defibrating machine, and it is difficult to strictly adjust the viscosity and the procedure is complicated.
The present invention solves such a problem, and can be expected to be used for various uses such as fine fibrous cellulose, such as a thickener for cosmetics and food, and a composite with a resin.

Claims (8)

The fiber width contains fine fibrous cellulose of 1,000 nm or less, and oxo acid containing chlorine or a salt thereof,
The content of oxo acid or a salt thereof containing chlorine relative to 100 parts by mass of fine fibrous cellulose is 0.0001 to 10 parts by mass,
A fine fibrous cellulose-containing composition.   The fine fibrous material according to claim 1, wherein the chlorine-containing oxo acid or a salt thereof includes at least one selected from the group consisting of sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite. Cellulose-containing composition. When the solid content concentration of the fine fibrous cellulose is 0.4% by mass, the viscosity of the composition measured by rotating the composition at a rotation speed of 3 rpm at 23 ° C. for 3 minutes using a Brookfield viscometer is 1.0. The fine fibrous cellulose-containing composition according to claim 1, wherein the composition is not more than × 10 ⁴ mPa · s.   The fine fibrous cellulose has an ionic substituent, and the content of the ionic substituent is 0.60 mmol / g or more with respect to the fine fibrous cellulose. Fine fibrous cellulose-containing composition.   The fine fibrous cellulose-containing composition according to any one of claims 1 to 4, wherein the composition has a haze at 23 ° C of 1.5% or less when the solid content concentration of the fine fibrous cellulose is 0.2% by mass. .   The fine fibrous cellulose-containing composition according to any one of claims 1 to 5, wherein the content of oxo acid or a salt thereof containing chlorine relative to 100 parts by mass of the fine fibrous cellulose is 0.005 to 2 parts by mass. object. Fibrillating cellulose in a solvent to obtain a dispersion containing fine fibrous cellulose, and adding chlorine-containing oxo acid or a salt thereof to the dispersion containing fine fibrous cellulose. Have
The addition amount of oxo acid or a salt thereof containing chlorine relative to 100 parts by mass of the fine fibrous cellulose is 0.0001 to 10 parts by mass,
A method for producing a fine fibrous cellulose-containing composition.   The method for producing a fine fibrous cellulose-containing composition according to claim 7, wherein the fibrous cellulose has an ionic substituent.