JP6954257B2 - Fibrous cellulose-containing composition, its production method, and membrane - Google Patents

Description

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

In recent years, due to the substitution of petroleum resources and heightened environmental awareness, materials using reproducible natural fibers have been attracting attention. Among natural fibers, fibrous cellulose having a fiber diameter of 10 μm or more and 50 μm or less, particularly fibrous cellulose (pulp) derived from wood, has been widely used mainly as paper products.

As the fibrous cellulose, fine fibrous cellulose having a fiber diameter of 1 μm or less is also known. In recent years, a sheet composed of such fine fibrous cellulose and a composite sheet containing a fine fibrous cellulose-containing sheet and a resin have been developed. Further, since the fine fibrous cellulose can exert a thickening effect, it is also considered to use the fine fibrous cellulose as a thickener for various purposes.

As a method for producing a dispersion of fine fibrous cellulose, Patent Document 1 describes that chemically modified cellulose fibers are defibrated to obtain a cellulose nanofiber dispersion. Patent Document 1 describes that an enzyme-treated cellulose fiber may be used as the chemically modified cellulose fiber. Further, Patent Document 2 describes that finely divided cellulose oxide is obtained in an aqueous medium to obtain a dispersion liquid of fine cellulose fibers. Patent Document 2 describes that the cellulose raw material may be treated with an enzyme.

JP-A-2017-2136 Japanese Unexamined Patent Publication No. 2015-221844

The present inventors have studied the use of fine fibrous cellulose for the purpose of reinforcing paints. However, since the fine fibrous cellulose has a high viscosity, it has been difficult to add a sufficient amount of the fine fibrous cellulose for reinforcement in applications where the increase in viscosity is not desired. For example, when forming a coating film with a paint, the lower the viscosity of the fine fibrous cellulose, the better the coating suitability. An object to be solved by the present invention is to provide a cellulose-containing composition having excellent coating suitability, a method for producing the same, and a film.

As a result of diligent studies to solve the above problems, the present inventors have made a composition containing fibrous cellulose having a fiber width of 1000 nm or less by adding an enzyme to adjust the viscosity of the composition. , It has been found that it is possible to provide a cellulose-containing composition having excellent coating suitability. The present invention has been completed based on these findings.
The present invention has the following configurations.

[1] A cellulose-containing composition containing fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the protein contains an enzyme, and the content of the protein is 1 with respect to 1 part by mass of the fibrous cellulose. × 10 ^-3 parts by mass or less, and the viscosity measured under the conditions of 25 ° C. and 3 rpm with the solid content concentration of the fibrous cellulose being 0.4% by mass is 10 mPa · s or more and 11000 mPa · s or less. Containing composition.
[2] The cellulose-containing composition according to [1], wherein the content of the protein is 1 × ^{10-7 parts by mass or more with respect to 1 part by mass of the fibrous cellulose.}
[3] A cellulose-containing composition containing a fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the protein contains an enzyme, the endoglucanase activity of the enzyme is 840 U / L or less, and the fibrous cellulose. A cellulose-containing composition having a viscosity of 10 mPa · s or more and 11000 mPa · s or less measured under the conditions of 25 ° C. and 3 rpm with a solid content concentration of 0.4% by mass.
[4] The cellulose-containing composition according to [3], wherein the endoglucanase activity of the enzyme is 0.084 U / L or more.
[5] The cellulose-containing composition according to any one of [1] to [4], wherein the fibrous cellulose has an ionic substituent.
[6] The cellulose-containing composition according to any one of [1] to [5], wherein the fibrous cellulose has a phosphoric acid group or a substituent derived from a phosphoric acid group.
[7] The cellulose-containing composition according to any one of [1] to [6], wherein the degree of polymerization of the fibrous cellulose is 200 or more and 450 or less.
[8] A film containing fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the protein contains an enzyme, and the content of the protein is 1 × 10 ^{− with respect to 1 part by mass of the fibrous cellulose. A} film that is 3 parts by mass or less.
[9] The membrane according to [8], wherein the content of the protein is 1 × ^{10-7 parts by mass or more with respect to 1 part by mass of the fibrous cellulose.}
[10] A method for producing a cellulose-containing composition, which comprises a step of adding an enzyme of ^{1 × 10 -3} parts by mass or less to 1 part by mass of fibrous cellulose having a fiber width of 1000 nm or less.

According to the present invention, it is possible to provide a cellulose-containing composition having excellent coatability.

FIG. 1 is a graph showing the relationship between the amount of NaOH added to the fiber raw material and the electrical conductivity. FIG. 2 is a graph showing the relationship between the amount of NaOH added to the fiber raw material having a carboxyl group and the electrical conductivity.

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

(Cellulose-containing composition)
The present invention is a cellulose-containing composition containing a fibrous cellulose having a fiber width of 1000 nm or less (hereinafter, also referred to as fine fibrous cellulose) and a protein, wherein the protein contains an enzyme and the content of the protein is high. ^{The viscosity is 1 × 10 -3} parts by mass or less with respect to 1 part by mass of the fibrous cellulose, and the viscosity measured under the conditions of 25 ° C. and 3 rpm with the solid content concentration of the fibrous cellulose being 0.4% by mass is 10 mPa. -Regarding a cellulose-containing composition having s or more and 11000 mPa · s or less.

^{The protein content may be 1 × 10 -3} parts by mass or less with respect to 1 part by mass of fibrous cellulose, ^{preferably 1 × 10 -4} parts by mass or less, and more preferably 1 × 10 ^{-5 parts by mass or less.} , 5.0 × ^10-6 parts by mass or less is particularly preferable. ^{The protein content is preferably 1 × 10 -7} parts by mass or more, more preferably 3 × 10 ^-7 parts by mass or more, and further preferably 1 × 10 ^-6 parts by mass or more with respect to 1 part by mass of fibrous cellulose.
The protein content can be controlled by adjusting the addition amount of the enzyme, adjusting the production process of the fine fibrous cellulose including the enzyme treatment, and the like. In the present embodiment, the amount of protein can be adjusted depending on, for example, the timing of performing the enzyme treatment. Good coatability can be achieved by keeping the protein content within the above range.

The protein content in the cellulose-containing composition can be determined by, for example, the Burette method, the Lowry method, the fluorescence method, or the dye binding method. When determining the protein content by the burette method, add 4 times the amount of the burette drug to the bovine serum albumin aqueous solution (prepared so that the protein content is 5.0% by mass or less), mix, and mix 20 After leaving it to stand in an environment of ° C. to 25 ° C. for 30 minutes, the absorption wavelength of 540 nm is measured using a spectrophotometer, and a calibration curve is drawn based on the measured value. Next, 4 times the amount of the burette reagent was added to the cellulose-containing composition, mixed well, left to stand in an environment of 20 ° C. to 25 ° C. for 30 minutes, and then the absorption wavelength of 540 nm was measured using a spectrophotometer. do. By writing the measured value on the calibration curve, the amount of protein contained in the cellulose-containing composition can be determined.

Further, the present invention is a cellulose-containing composition containing fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the protein contains an enzyme, the endoglucanase activity of the enzyme is 840 U / L or less, and the fiber. The present invention relates to a cellulose-containing composition having a viscosity measured at 25 ° C. and a rotation speed of 3 rpm with a solid content concentration of 0.4% by mass as 10 mPa · s or more and 11000 mPa · s or less.

The endoglucanase activity of the enzyme may be 840 U / L or less. The lower limit of the endoglucanase activity of the enzyme is preferably 0.084 U / L or more, more preferably 0.84 U / L or more, more preferably 1 U / L or more, further preferably 2 U / L or more, and 3 U / L or more. Especially preferable. The upper limit of the endoglucanase activity of the enzyme is preferably 84 U / L or less, more preferably 8.4 U / L or less, further preferably 7 U / L or less, and particularly preferably 6 U / L or less.
The endoglucanase activity of the enzyme can be controlled by adjusting the amount of the enzyme added, adjusting the production process of the fine fibrous cellulose including the enzyme treatment, and the like. In the present embodiment, the endoglucanase activity of the enzyme can be adjusted, for example, depending on the timing of the enzyme treatment. Good coatability can be achieved by keeping the endoglucanase activity of the enzyme within the above range.

The endoglucanase activity (also referred to as EG activity) of the enzyme in the cellulose-containing composition can be measured as follows.
A substrate solution of carboxylmethylcellulose at a concentration of 1% (W / V) (concentration 100 mM, containing a pH 5.0 sodium acetate-sodium acetate buffer) is prepared. Immediately after production, the cellulose-containing composition is diluted with a buffer solution (similar to the above) in advance (the dilution ratio is such that the absorbance of the enzyme solution below is within the calibration curve obtained from the glucose standard solution below). To 90 μl of the substrate solution, 10 μl of the diluted evaluation slurry solution is added, and the mixture is reacted at 37 ° C. for 30 minutes. To prepare a calibration curve, select ion-exchanged water (blank) and glucose standard solution (4 standard solutions with at least different concentrations from 0.5 to 5.6 mM), prepare 100 μl each, and prepare at 37 ° C. Keep warm for 30 minutes. 300 μl of DNS color-developing solution (1.6% by mass NaOH, 1% by mass 3,5-dinitrosalicylic acid, 30% by mass, respectively, in the slurry solution for enzyme-containing evaluation after the reaction, the blank for the calibration line, and the glucose standard solution. (Potassium tartrate sodium) is added and boiled for 5 minutes to develop color. Immediately after color development, the mixture was ice-cooled, 2 ml of ion-exchanged water was added, and the mixture was mixed well. After allowing to stand for 30 minutes, the absorbance is measured within 1 hour. For the measurement of absorbance, 200 μl is dispensed into a 96-well microwell plate, and the absorbance at 540 nm is measured using a microplate reader. A calibration curve is prepared using the absorbance and glucose concentration of each glucose standard solution minus the absorbance of the blank. The amount of glucose equivalent produced in the cellulose-containing composition is calculated by subtracting the absorbance of the blank from the absorbance of the cellulose-containing composition and then using a calibration curve. The amount of enzyme that produces 1 μmol of reducing sugar equivalent to glucose in 1 minute is defined as 1 unit, and the EG activity is calculated from the following formula.
EG activity = Glucose equivalent production amount (μmol) / 30 minutes x dilution ratio of 1 ml of cellulose-containing composition obtained by diluting with a buffer solution

The cellulose-containing composition of the present invention may have a viscosity of 10 mPa · s or more and 11000 mPa · s or less measured under the conditions of 25 ° C. and 3 rpm with a solid content concentration of fibrous cellulose of 0.4% by mass. The lower limit of the viscosity is preferably 100 mPa · s or more, more preferably 200 mPa · s or more, further preferably 500 mPa · s or more, and particularly preferably 1000 mPa · s or more. The upper limit of the viscosity is preferably 10,000 mPa · s or less.
8000 mPa · s or less is more preferable, 6500 mPa · s or less is further preferable, 5000 mPa · s or less is further preferable, 4000 mPa · s or less is further preferable, 3000 mPa · s or less is particularly preferable, and 2000 mPa · s or less is most preferable.

The viscosity is adjusted to a solid content concentration of 0.4% by mass by pouring ion-exchanged water 24 hours after the production of the cellulose-containing composition, and then allowed to stand for 24 hours in an environment of 25 ° C. , B-type viscometer (No. 3 rotor, No. 2 rotor, or No. 1 rotor) (BLOOKFIELD, analog viscometer T-LVT) was used to rotate at 25 ° C. at a rotation speed of 3 rpm for 3 minutes. It is the viscosity measured by.

The cellulose-containing composition of the present invention has the above-mentioned structure, so that the coating suitability is improved. In the present invention, by adding an enzyme to the defibrated fine fibrous cellulose, it is possible to efficiently adjust the viscosity of the fine fibrous cellulose without relying on mechanical treatment, which makes it suitable for coating. It can be improved. Further, since the viscosity can be efficiently reduced by adding the enzyme to the fine fibrous cellulose after defibration, the amount of the enzyme to be added can be reduced. When a film is produced using the cellulose-containing composition of the present invention, the optical and mechanical properties of the film can be improved by the above-mentioned effects. It is presumed that this is because when a large amount of enzyme is added, it is possible to suppress deterioration of physical properties due to crystallization of the enzyme-derived protein.

The form of the cellulose-containing composition is not particularly limited, and can exist in various forms such as powder, slurry, and solid. Above all, the cellulose-containing composition is preferably a slurry.

(Fibrous cellulose)
The cellulose-containing composition of the present invention contains fibrous cellulose (also referred to as fine fibrous cellulose) having a fiber width of 1000 nm or less. The fine fibrous cellulose is preferably a fiber having an ionic substituent, and in this case, the ionic substituent is preferably an anionic substituent (hereinafter, also referred to as an anionic substituent). Examples of the anion group include a phosphate group or a substituent derived from a phosphate group (sometimes simply referred to as a phosphate group), a carboxyl group or a substituent derived from a carboxyl group (sometimes simply referred to as a carboxyl group), and the like. In addition, it is preferably at least one selected from a sulfone group or a substituent derived from a sulfone group (sometimes simply referred to as a sulfone group), and at least one selected from a phosphate group and a carboxyl group. Is more preferable, and a phosphoric acid group is particularly preferable.

The content of the fine fibrous cellulose is preferably 0.5% by mass or more, more preferably 5% by mass or more, and more preferably 20% by mass or more, based on the total solid content of the cellulose-containing composition. It is even more preferably 40% by mass or more, even more preferably 50% by mass or more, and most preferably 55% by mass or more. The content of the fine fibrous cellulose is preferably 95% by mass or less.

The fibrous cellulose raw material for obtaining fine fibrous cellulose is not particularly limited, but pulp is preferably used because it is easily available and inexpensive. Examples of the pulp include wood pulp, non-wood pulp, and deinked pulp. Examples of wood pulp include broadleaf kraft pulp (LBKP), coniferous kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), and oxygen bleached craft. Examples thereof include chemical pulp such as pulp (OKP). Further, semi-chemical pulp such as semi-chemical pulp (SCP) and chemiground wood pulp (CGP), mechanical pulp such as crushed wood pulp (GP) and thermomechanical pulp (TMP, BCTMP) and the like can be mentioned, but are not particularly limited. Examples of the non-wood pulp include cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw and bagasse, and cellulose, chitin and chitosan isolated from sea squirts and seaweed, but are not particularly limited. .. Examples of the deinked pulp include deinked pulp made from used paper, but the deinking pulp is not particularly limited. As the pulp of the present embodiment, one of the above types may be used alone, or two or more types may be mixed and used. Among the above pulps, wood pulp containing cellulose and deinked pulp are preferable in terms of availability. Among wood pulps, chemical pulp has a large cellulose ratio, so the yield of fine fibrous cellulose during fiber refining (defibration) is high, the decomposition of cellulose in the pulp is small, and the fine fibers with a large axial ratio are fine. It is preferable in that fibrous cellulose can be obtained. Of these, kraft pulp and sulfite pulp are most preferably selected. A film containing fine fibrous cellulose of long fibers having a large axial ratio tends to obtain high strength.

The average fiber width of the fine fibrous cellulose is 1000 nm or less when observed with an electron microscope. The average fiber width is preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and less than 1000 nm, more preferably 2 nm or more and 100 nm or less, more preferably 2 nm or more and 50 nm or less, and further preferably 2 nm or more and 10 nm or less. , Not particularly limited. If the average fiber width of the fine fibrous cellulose is less than 2 nm, it is dissolved in water as a cellulose molecule, so that the physical properties (strength, rigidity, dimensional stability) of the fine fibrous cellulose tend to be difficult to develop. .. The fine fibrous cellulose is, for example, a monofibrous cellulose having a fiber width of 1000 nm or less.

The fiber width of the fine fibrous cellulose is measured by electron microscope observation as follows. An aqueous suspension of fine 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 hydrophilized carbon film-coated grid to prepare a sample for TEM observation. do. If it contains wide fibers, an SEM image of the surface cast on the glass may be observed. Observation with an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 times, or 50,000 times depending on the width of the constituent fibers. However, the sample, observation conditions and magnification should be adjusted so as to satisfy the following conditions.

(1) A straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y that intersects the straight line perpendicularly is drawn in the same image, and 20 or more fibers intersect the straight line Y.

The width of the fiber intersecting the straight line X and the straight line Y is visually read with respect to the observation image satisfying the above conditions. In this way, at least three sets of images of the non-overlapping surface portions are observed, and the widths of the fibers intersecting the straight lines X and Y are read for each image. In this way, at least 20 fibers × 2 × 3 = 120 fibers are read. The average fiber width of the fine fibrous cellulose (sometimes simply referred to as "fiber width") is the average value of the fiber widths read in this way.

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

The fine fibrous cellulose preferably has an I-type crystal structure. Here, the fact that the fine fibrous cellulose has an I-type crystal structure can be identified in the diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418 Å) monochromatic with graphite. Specifically, it can be identified by having typical peaks at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less.
The ratio of the type I crystal structure to the fine fibrous cellulose is preferably 30% or more, more preferably 50% or more, still more preferably 70% or more. In this case, further excellent performance can be expected in terms of heat resistance and low coefficient of linear thermal expansion. The crystallinity is determined by a conventional method from the X-ray diffraction profile measured and the pattern (Seagal et al., Textile Research Journal, Vol. 29, p. 786, 1959).

The fine fibrous cellulose preferably has a phosphoric acid group or a substituent derived from the phosphoric acid group. The phosphoric acid group is a divalent functional group obtained by removing the hydroxyl group from phosphoric acid. Specifically, it is a group represented by _{−PO 3} H _2. Substituents derived from phosphoric acid groups include substituents such as a group obtained by decomposing a phosphoric acid group, a salt of a phosphoric acid group, and a phosphoric acid ester group, and even if it is an ionic substituent, it is a nonionic substituent. It may be a group.

In the present invention, the phosphate group or the substituent derived from the phosphoric acid group may be a substituent represented by the following formula (1).

In formula (1), a, b, m and n each independently represent an integer (where a = b × m); α and α ′ independently represent R or OR, respectively. R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched chain hydrocarbon group. , Aromatic groups, or inducing groups thereof; β is a monovalent or higher cation consisting of an organic or inorganic substance.

<Introduction of phosphate group>
The introduction of the phosphoric acid group is carried out by reacting a fiber raw material containing cellulose with at least one selected from a compound having a phosphoric acid group and a salt thereof (hereinafter, referred to as "phosphorylation reagent" or "compound A"). Can be done by Such phosphorylation reagents may be mixed with the dry or wet fiber raw material in the form of powder or aqueous solution. As another example, a powder or an aqueous solution of a phosphorylation reagent may be added to the slurry of the fiber raw material.

The introduction of the phosphoric acid group can be carried out by reacting a fiber raw material containing cellulose with at least one selected from a compound having a phosphoric acid group and a salt thereof (phosphorylation reagent or compound A). This reaction may be carried out in the presence of at least one selected from urea and its derivatives (hereinafter referred to as "Compound B").

An example of a method of allowing compound A to act on a fiber raw material in the coexistence of compound B includes a method of mixing a powder or an aqueous solution of compound A and compound B with a fiber raw material in a dry state or a wet state. Another example is a method of adding a powder or an aqueous solution of Compound A and Compound B to a slurry of a fiber raw material. Of these, since the reaction uniformity is high, a method of adding an aqueous solution of compound A and compound B to a dry fiber raw material, or adding a powder or aqueous solution of compound A and compound B to a wet fiber raw material. The method is preferred. Further, compound A and compound B may be added at the same time or separately. Alternatively, compound A and compound B to be tested in the reaction may be added as an aqueous solution first, and the excess chemical solution may be removed by squeezing. The form of the fiber raw material is preferably cotton-like or thin sheet-like, but is not particularly limited.

The compound A used in this embodiment is at least one selected from a compound having a phosphoric acid group and a salt thereof.
Examples of the compound having a phosphoric acid group include, but are not limited to, phosphoric acid, a lithium salt of phosphoric acid, a sodium salt of phosphoric acid, a potassium salt of phosphoric acid, an ammonium salt of phosphoric acid, and the like. Examples of the lithium salt of phosphoric acid include lithium dihydrogen phosphate, dilithium hydrogen phosphate, trilithium phosphate, lithium pyrophosphate, and lithium polyphosphate. Examples of the sodium salt of phosphoric acid include sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, and sodium polyphosphate. Examples of the potassium salt of phosphoric acid include potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, potassium polyphosphate and the like. Examples of the ammonium salt of phosphoric acid include ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium polyphosphate.

Of these, from the viewpoints of high efficiency of introduction of phosphoric acid group, easy improvement of defibration efficiency in the defibration step described later, low cost, and easy industrial application, phosphoric acid and phosphoric acid A sodium salt, a potassium salt of phosphoric acid, or an ammonium salt of phosphoric acid is preferable. Sodium dihydrogen phosphate or disodium hydrogen phosphate is more preferred.

Further, the compound A is preferably used as an aqueous solution because the uniformity of the reaction is enhanced and the efficiency of introducing the phosphoric acid group is increased. The pH of the aqueous solution of compound A is not particularly limited, but is preferably 7 or less because the efficiency of introducing a phosphoric acid group is high, and more preferably 3 or more and pH 7 or less from the viewpoint of suppressing hydrolysis of pulp fibers. For example, the pH of the aqueous solution of the compound A may be adjusted by using a compound having an acidic group and a compound showing an alkalinity in combination and changing the amount ratio thereof. The pH of the aqueous solution of the compound A may be adjusted by adding an inorganic alkali or an organic alkali to the compound having a phosphoric acid group and showing acidity.

The amount of compound A added to the fiber raw material is not particularly limited, but when the amount of compound A added is converted to the phosphorus atomic weight, the amount of phosphorus atom added to the fiber raw material (absolute dry mass) is 0.5% by mass or more and 100% by mass. The following is preferable, 1% by mass or more and 50% by mass or less is more preferable, and 2% by mass or more and 30% by mass or less is most preferable. When the amount of phosphorus atom added to the fiber raw material is within the above range, the yield of fine fibrous cellulose can be further improved. Further, by setting the addition amount of the phosphorus atom to the fiber raw material to 100% by mass or less, the cost of the compound A to be used can be suppressed while increasing the phosphorylation efficiency.

Examples of compound B used in this embodiment include urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like.

Compound B is preferably used as an aqueous solution like compound A. Further, since the uniformity of the reaction is enhanced, it is preferable to use an aqueous solution in which both compound A and compound B are dissolved. The amount of Compound B added to the fiber raw material (absolute dry mass) is 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, and 100% by mass or more and 350% by mass or less. It is more preferably 150% by mass or more, and particularly preferably 300% by mass or less.

In addition to Compound A and Compound B, amides or amines may be included in the reaction system. Examples of amides include formamide, dimethylformamide, acetamide, dimethylacetamide and the like. Examples of amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine and the like. Among these, triethylamine in particular is known to act as a good reaction catalyst.

When introducing the phosphoric acid group, it is preferable to perform heat treatment. The heat treatment temperature is preferably selected so that the phosphoric acid group can be efficiently introduced while suppressing the thermal decomposition and hydrolysis reaction of the fiber. Specifically, it is preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower. Further, a vacuum dryer, an infrared heating device, and a microwave heating device may be used for heating.

During the heat treatment, if the fiber raw material is allowed to stand for a long time while the fiber raw material slurry to which the compound A is added contains water, the water molecules and the dissolved compound A move to the surface of the fiber raw material as it dries. do. Therefore, the concentration of the compound A in the fiber raw material may be uneven, and the introduction of the phosphoric acid group to the fiber surface may not proceed uniformly. In order to suppress the occurrence of uneven concentration of compound A in the fiber raw material due to drying, a very thin sheet-shaped fiber raw material is used, or the fiber raw material and compound A are kneaded or agitated with a kneader or the like and dried by heating or under reduced pressure. You can take the method.

The heating device used for the heat treatment is preferably a device capable of constantly discharging the water retained by the slurry and the water generated by the addition reaction of fibers such as phosphoric acid groups to the hydroxyl groups to the outside of the device system. For example, a ventilation type oven. Etc. are preferable. If the water in the apparatus system is constantly discharged, the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the phosphate esterification, can be suppressed, and the acid hydrolysis of the sugar chain in the fiber can also be suppressed. , Fine fibers with a high axial ratio can be obtained.

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

The amount of the phosphoric acid group introduced is preferably 5.20 mmol / g or less, more preferably 0.1 mmol / g or more and 3.65 mmol / g or less, and 0. .14 mmol / g or more and 3.5 mmol / g or less is even more preferable, 0.2 mmol / g or more and 3.2 mmol / g or less is further preferable, 0.4 mmol / g or more and 3.0 mmol / g or less is particularly preferable, and most preferable. Is 0.6 mmol / g or more and 2.5 mmol / g or less. By setting the amount of the phosphoric acid group introduced within the above range, it is possible to facilitate the miniaturization of the fiber raw material and enhance the stability of the fine fibrous cellulose. Further, by setting the amount of the phosphoric acid group introduced within the above range, it is possible to leave hydrogen bonds between the fine fibrous celluloses while facilitating the miniaturization, and the strength is good when the film is formed. Expression can be expected.

The amount of the phosphoric acid group introduced into the fiber raw material can be measured by the conductivity titration method. Specifically, it is refined by a defibration treatment step, the obtained fine fibrous cellulose-containing slurry is treated with an ion exchange resin, and then the change in electrical conductivity is obtained while adding an aqueous sodium hydroxide solution. The amount introduced can be measured.

In the conductivity titration, the addition of alkali gives the curve shown in FIG. Initially, the electrical conductivity drops sharply (hereinafter referred to as the "first region"). After that, the conductivity begins to increase slightly (hereinafter referred to as "second region"). After that, the increment of conductivity increases (hereinafter referred to as "third region"). That is, three regions appear. The boundary point between the second region and the third region is defined by the point at which the second derivative value of the conductivity, that is, the amount of change in the increment (slope) of the conductivity is maximized. Of these, the amount of alkali required in the first region is equal to the amount of strong acid groups in the slurry used for titration, and the amount of alkali required in the second region is equal to the amount of weakly acidic groups in the slurry used for titration. Become equal. When the phosphoric acid group causes condensation, the weakly acidic group is apparently lost, and the amount of alkali required for the second region is smaller than the amount of alkali required for the first region. On the other hand, since the amount of strongly acidic groups is the same as the amount of phosphorus atoms regardless of the presence or absence of condensation, it is simply referred to as the amount of phosphate groups introduced (or the amount of phosphate groups) or the amount of substituents introduced (or the amount of substituents). When it is said, it means the amount of strongly acidic groups. That is, the amount of alkali (mmol) required in the first region of the curve shown in FIG. 1 is divided by the solid content (g) in the slurry to be titrated to obtain the amount of substituent introduced (mmol / g).

The phosphoric acid group introduction step may be performed at least once, but may be repeated a plurality of times. In this case, more phosphate groups are introduced, which is preferable.

<Introduction of carboxyl group>
In the present invention, when the fine fibrous cellulose has a carboxyl group, the fiber raw material is subjected to an oxidation treatment such as a TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) oxidation treatment. Alternatively, a carboxyl group can be introduced by treatment with a compound having a group derived from a carboxylic acid, a derivative thereof, or an acid anhydride thereof or a derivative thereof.

The compound having a carboxyl group is not particularly limited, and examples thereof include dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid and itaconic acid, and tricarboxylic acid compounds such as citric acid and aconitic acid. ..

The acid anhydride of the compound having a carboxyl group is not particularly limited, and examples thereof include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. Be done.

The derivative of the compound having a carboxyl group is not particularly limited, and examples thereof include an imide of an acid anhydride of a compound having a carboxyl group and a derivative of an acid anhydride of a compound having a carboxyl group. The imide of the acid anhydride of the compound having a carboxyl group is not particularly limited, and examples thereof include an imide of a dicarboxylic acid compound such as maleimide, succinateimide, and phthalateimide.

The derivative of the acid anhydride of the compound having a carboxyl group is not particularly limited. For example, at least a part of hydrogen atoms of the acid anhydride of a compound having a carboxyl group, such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride, etc., are substituents (for example, alkyl group, phenyl group, etc.). ) Replaced by).

The amount of the carboxyl group introduced is preferably 0.1 mmol / g or more and 3.65 mmol / g or less, and more preferably 0.14 mmol / g or more and 3.5 mmol / g or less per 1 g (mass) of the fine fibrous cellulose. It is more preferably 0.2 mmol / g or more and 3.2 mmol / g or less, particularly preferably 0.4 mmol / g or more and 3.0 mmol / g or less, and most preferably 0.6 mmol / g or more and 2.5 mmol / g or less.
The amount of the carboxyl group introduced into the fiber raw material can be measured by the conductivity titration method. In the conductivity titration, the addition of alkali gives the curve shown in FIG. The amount of alkali (mmol) required in the first region of the curve shown in FIG. 2 is divided by the solid content (g) in the slurry to be titrated to obtain the amount of substituent introduced (mmol / g).

<Alkaline treatment>
When producing fine fibrous cellulose, an alkali treatment may be performed between the ionic functional group introduction step and the defibration treatment step described later. The alkaline treatment method is not particularly limited, and examples thereof include a method of immersing the functional group-introduced fiber in an alkaline solution.
The alkaline compound contained in the alkaline solution is not particularly limited, but may be an inorganic alkaline compound or an organic alkaline compound. The solvent in the alkaline solution may be either water or an organic solvent. The solvent is preferably a polar solvent (water or a polar organic solvent such as alcohol), and more preferably an aqueous solvent containing at least water.
Further, among the alkaline solutions, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is particularly preferable because of its high versatility.

The temperature of the alkaline solution in the alkaline treatment step is not particularly limited, but is preferably 5 ° C. or higher and 80 ° C. or lower, and more preferably 10 ° C. or higher and 60 ° C. or lower.
The immersion time in the alkaline solution in the alkaline treatment step is not particularly limited, but is preferably 5 minutes or more and 30 minutes or less, and more preferably 10 minutes or more and 20 minutes or less.
The amount of the alkaline solution used in the alkaline treatment is not particularly limited, but is preferably 100% by mass or more and 100,000% by mass or less, and 1000% by mass or more and 10000% by mass or less with respect to the absolute dry mass of the phosphate group-introduced fiber. Is more preferable.

In order to reduce the amount of the alkaline solution used in the alkaline treatment step, the functional group-introduced fibers may be washed with water or an organic solvent before the alkaline treatment step. After the alkali treatment, it is preferable to wash the alkali-treated functional group-introduced fibers with water or an organic solvent before the defibration treatment step in order to improve the handleability.

<Fiber processing>
The fibrous cellulose is defibrated in the defibration treatment step. In the defibration treatment step, the fibers are usually defibrated using a defibration treatment device to obtain a fine fibrous cellulose-containing slurry, but the treatment device and the treatment method are not particularly limited.
As the defibration processing apparatus, a high-speed defibrator, a grinder (stone mill type crusher), a high-pressure homogenizer, an ultra-high pressure homogenizer, a high-pressure collision type crusher, a ball mill, a bead mill and the like can be used. Alternatively, as the defibration processing device, use a wet pulverizing device such as a disc type refiner, a conical refiner, a twin-screw kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, or a beater. You can also. The defibration processing apparatus is not limited to the above. Preferred defibration treatment methods include a high-speed defibrator, a high-pressure homogenizer, and an ultra-high-pressure homogenizer, which are less affected by crushed media and less likely to cause contamination.

At the time of the defibration treatment, it is preferable to dilute the fiber raw material alone or in combination with water and an organic solvent to form a slurry, but the fiber raw material is not particularly limited. As the dispersion medium, a polar organic solvent can be used in addition to water. Preferred polar organic solvents include, but are not limited to, alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc) and the like. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, t-butyl alcohol and the like. Examples of the ketones include acetone, methyl ethyl ketone (MEK) and the like. Examples of ethers include diethyl ether and tetrahydrofuran (THF). The dispersion medium may be one kind or two or more kinds. Further, the dispersion medium may contain a solid content other than the fiber raw material, for example, urea having a hydrogen bond property.

The fine fibrous cellulose may be obtained by once concentrating and / or drying the fine fibrous cellulose-containing slurry obtained by the defibration treatment, and then performing the defibration treatment again. In this case, the method of concentration and drying is not particularly limited, and examples thereof include a method of adding a concentrating agent to a slurry containing fine fibrous cellulose, a method of using a commonly used dehydrator, press, and dryer. In addition, known methods such as those described in WO2014 / 024876, WO2012 / 107642, and WO2013 / 121086 can be used. Further, it is also possible to concentrate and dry the fine fibrous cellulose-containing slurry by forming it into a sheet, defibrate the sheet, and obtain the fine fibrous cellulose-containing slurry again.

After concentrating and / or drying the fine fibrous cellulose-containing slurry, the equipment used when defibrating (crushing) again is a high-speed defibrator, a grinder (stone mill type crusher), a high-pressure homogenizer, and an ultra-high pressure homogenizer. , High-pressure collision type crusher, ball mill, bead mill, disc type refiner, conical refiner, twin-screw kneader, vibration mill, homomixer under high-speed rotation, ultrasonic disperser, beater, etc. It can be done, but it is not particularly limited.

<Enzyme treatment>
The cellulose-containing composition of the present invention contains a protein, and the protein contains an enzyme.
The enzyme used in the present invention is a cellulase-based enzyme and is classified into a sugar hydrolase family based on the higher-order structure of a catalytic domain having a cellulolytic reaction function. Cellulase-based enzymes are classified into endo-glucanase and cellobiohydrolase according to their cellulolytic properties. Endo-type glucanase is highly hydrolyzable to an amorphous portion of cellulose, soluble cellooligosaccharide, or a cellulose derivative such as carboxymethyl cellulose, and randomly cleaves their molecular chains from the inside to reduce the degree of polymerization. However, endo-type glucanase has low hydrolysis reactivity to crystalline cellulose microfibrils. In contrast, cellobiohydrolase decomposes the crystalline portion of cellulose to give cellobiose. In addition, cellobiohydrolase hydrolyzes from the end of the cellulose molecule and is also called an exo-type or processive enzyme. In the present invention, it is preferable to use endo-type glucanase.

As the enzyme used in the present invention, hemicellulase-based enzymes may be used in addition to endo-type glucanase and cellobiohydrolase. Among the hemicellulase-based enzymes, xylanase, which is an enzyme that decomposes xylan, mannase, which is an enzyme that decomposes mannan, and arabanase, which is an enzyme that decomposes araban, can be mentioned. In addition, pectinase, which is an enzyme that decomposes pectin, can also be used as a hemicellulase-based enzyme. Microorganisms that produce hemicellulase-based enzymes often also produce cellulase-based enzymes.

Hemicellulose is a polysaccharide excluding pectins located between cellulose microfibrils in the plant cell wall. Hemicellulose is diverse and varies between plant types and cell wall layers. In wood, glucomannan is the main component in the secondary wall of softwood, and 4-O-methylglucuronoxylan is the main component in the secondary wall of hardwood. Therefore, it is preferable to use mannase in order to obtain fine fibers from softwood, and in the case of hardwood, it is preferable to use xylanase.

According to the present invention, there is provided a method for producing a cellulose-containing composition, which comprises a step of adding an enzyme of ^{1 × 10 -3} parts by mass or less to 1 part by mass of fibrous cellulose having a fiber width of 1000 nm or less. .. By adding the enzyme to the fine fibrous cellulose, the fine fibrous cellulose can be reacted with the enzyme. In the present invention, it is possible to adopt a form in which the washing step of the fine fibrous cellulose is not performed after the enzyme treatment.
In the present invention, the enzyme may be inactivated after the enzyme treatment. As a method for inactivating the enzyme, a mixture of fine fibrous cellulose and enzyme is heated to 100 ° C. and allowed to stand for 30 minutes to 1 hour while maintaining the temperature, or a mixture of fine fibrous cellulose and enzyme. On the other hand, the pH may be adjusted to 10 or more by adding a strong base, but the pH is not particularly limited.
The cellulose-containing composition of the present invention can be produced by the above-mentioned method for producing a cellulose-containing composition.

The amount of the enzyme added to 1 part by mass of fibrous cellulose having a fiber width of 1000 nm or less may be ^{1 × 10 -3 parts by mass or less, preferably 1 × 10 -4} parts by mass or less, and 1 × 10 ^{−. 5} parts by mass or less is more preferable, and 5.0 × ^10-6 parts by mass or less is particularly preferable. ^{The amount of the enzyme added is preferably 1 × 10 -7} parts by mass or more, more preferably 3 × 10 ^-7 parts by mass or more, and further preferably 1 × 10 ^-6 parts by mass or more with respect to 1 part by mass of fibrous cellulose. preferable.
By setting the amount of the enzyme added within the above range, good coating suitability of the produced cellulose-containing composition can be achieved.

The reaction time between the fine fibrous cellulose and the enzyme is not particularly limited, but is generally preferably 1 minute to 24 hours, more preferably 1 minute to 1 hour.
The reaction temperature and reaction pH of the fine fibrous cellulose and the enzyme are preferably kept at the optimum temperature and the optimum pH of the enzyme to be used, and are generally set to 20 ° C. to 80 ° C. and pH 4.5 to 9.5. It is preferable to keep it.
By setting the reaction conditions within the above range, good coatability of the produced cellulose-containing composition can be achieved.

<Degree of polymerization>
In the cellulose-containing composition of the present invention, the degree of polymerization of the fibrous cellulose is not particularly limited, but is preferably 200 or more and 450 or less, more preferably 250 or more and 400 or less, and more preferably 250 or more and 350 or less. Even more preferably, it is 270 or more and 300 or less.

The degree of polymerization of fibrous cellulose is calculated with reference to the following paper.
TAPPI International Standard; ISO / FDIS 5351, 2009.
Smith, DK; Bampton, RF; Alexander, WJ Ind. Eng. Chem., Process Des. Dev. 1963, 2, 57-62.

Specifically, 30 g of a suspension obtained by diluting fine fibrous cellulose with ion-exchanged water so that the content is 2 ± 0.3% by mass is divided into a centrifuge tube and allowed to stand in a freezer overnight. , Freeze. Further, it is dried in a freeze dryer for 5 days or more, and then heated in a constant temperature dryer set at 105 ° C. for 3 hours or more and 4 hours or less to obtain fine fibrous cellulose in an absolutely dry state.
To measure the reference, 15 ml of pure water and 15 ml of 1 mol / L copper ethylenediamine are added to an empty 50 ml capacity screw tube to prepare a 0.5 mol / L copper ethylenediamine solution. 10 ml of the above 0.5 mol / L copper ethylenediamine solution is placed in a Canon Fenceke viscometer, left for 5 minutes, and then the drop time at 25 ° C. is measured to determine the solvent drop time.

Next, in order to measure the viscosity of the fine fibrous cellulose, 0.14 g or more and 0.16 g or less of the absolutely dry fine fibrous cellulose is weighed into an empty 50 ml capacity screw tube, and 15 ml of pure water is added. Further, 15 ml of 1 mol / L copper ethylenediamine is added, and the mixture is stirred with a rotating and revolving supermixer at 1000 rpm for 10 minutes to prepare a 0.5 mol / L copper ethylenediamine solution in which fine fibrous cellulose is dissolved. In the same manner as the reference measurement, 10 ml of the prepared 0.5 mol / L copper ethylenediamine solution is placed in a Canon Fenceke viscometer, left for 5 minutes, and then the drop time at 25 ° C. is measured. The fall time is measured three times, and the average value is taken as the fall time of the fine fibrous cellulose solution.

The degree of polymerization is calculated from the mass of the absolutely dry fine fibrous cellulose used for the measurement, the solvent drop time, and the fall time of the fine fibrous cellulose solution using the following formula. The following average degree of polymerization is the average value of each measurement when measured twice or more.
Absolutely dry fine fibrous cellulose mass used for measurement: a (g) (where a is 0.14 or more and 0.16 or less)
Cellulose concentration in solution: c = a / 30 (g / mL)
Solvent drop time: t ₀ (sec)
Falling time of fine fibrous cellulose solution: t (sec)
Relative viscosity of solution: η _rel = t / t ₀
Specific viscosity of solution: η _sp = η _rel- 1
Intrinsic viscosity: [η] = η _{sp /} c (1 + 0.28 _{η sp} )
Degree of polymerization: DP = [η] /0.57
Since the average degree of polymerization of the fine fibrous cellulose is calculated by the above method, it is sometimes called the viscosity average degree of polymerization.

(Hydrophilic polymer)
The cellulose-containing composition of the present invention may further contain a hydrophilic polymer. In particular, when the fibrous cellulose-containing composition is a slurry for forming a coating film, it preferably contains a hydrophilic polymer. Since the coating film forming slurry contains a hydrophilic polymer, a fine fibrous cellulose-containing film having high transparency and excellent mechanical strength can be obtained.

Examples of the hydrophilic polymer include polyethylene glycol, cellulose derivatives (hydroxyethyl cellulose, carboxyethyl cellulose, carboxymethyl cellulose, etc.), casein, dextrin, starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol, etc.), and the like. Examples thereof include polyethylene oxide, polyvinylpyrrolidone, polyvinylmethyl ether, polyacrylates, polyacrylamide, acrylic acid alkyl ester copolymer, and urethane-based copolymer. Among them, the hydrophilic polymer is preferably at least one selected from polyethylene glycol (PEG), polyvinyl alcohol (PVA), modified polyvinyl alcohol (modified PVA) and polyethylene oxide (PEO), and polyethylene oxide (PEO). ) Is more preferable.

The content of the hydrophilic polymer is preferably 0.5 parts by mass or more, more preferably 3 parts by mass or more, and 5 parts by mass or more with respect to 100 parts by mass of fibrous cellulose. It is more preferably 10 parts by mass or more, and particularly preferably 10 parts by mass or more. The content of the hydrophilic polymer is preferably 5000 parts by mass or less, more preferably 1000 parts by mass or less, and preferably 500 parts by mass or less with respect to 100 parts by mass of fibrous cellulose. It is more preferably 100 parts by mass or less, and particularly preferably 100 parts by mass or less.

The viscosity-average molecular weight of the hydrophilic polymer is not particularly limited, it is preferably, 2.0 × 10 ³ or more 1.0 × 10 ⁷ or less is 1.0 × 10 ³ or more 1.0 × 10 ⁷ or less more preferably, it is more preferably 5.0 × 10 ³ or more 1.0 × 10 ⁷ or less.

(Arbitrary ingredient)
The fibrous cellulose-containing composition of the present invention may contain any component other than the above-mentioned components. Optional components include, for example, defoamers, lubricants, UV absorbers, dyes, pigments, stabilizers, surfactants, coupling agents, inorganic layered compounds, inorganic compounds, leveling agents, organic particles, antistatic agents. , Magnetic powder, orientation accelerator, plasticizer, preservative, cross-linking agent and the like. Moreover, you may add an organic ion as an optional component.

As an optional component, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like may be added. These resins may be added as emulsions. Specific examples of the thermosetting resin emulsion and the photocurable resin emulsion include those described in JP-A-2009-299043.

(Cellulose-containing membrane)
The present invention also relates to a cellulose-containing membrane formed from the above-mentioned cellulose-containing composition. The present invention is a cellulose-containing membrane containing fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the protein contains an enzyme, and the content of the protein is 1 with respect to 1 part by mass of the fibrous cellulose. × 10 ^-3 parts by mass or less, relating to a cellulose-containing film. In the specification of the present application, the film includes a film laminated on another base material, a sheet peeled off from the base material, and the like.

^{The protein content in the cellulose-containing membrane may be 1 × 10 -3} parts by mass or less with respect to 1 part by mass of fibrous cellulose, ^{preferably 1 × 10 -4} parts by mass or less, and 1 × 10 ^-5 parts by mass. The following is more preferable, and 5.0 × ^10-6 parts by mass or less is particularly preferable. ^{The protein content in the cellulose-containing membrane is preferably 1 × 10 -7} parts by mass or more, more preferably 3 × 10 ^-7 parts by mass or more, and 1 × 10 ^-6 parts by mass or more with respect to 1 part by mass of fibrous cellulose. Is even more preferable.
The protein content in the cellulose-containing membrane can be controlled by adjusting the addition amount of the enzyme, adjusting the production process of the fine fibrous cellulose including the enzyme treatment, and the like. In the present embodiment, the amount of protein in the cellulose-containing membrane can be adjusted, for example, due to the timing of performing the enzyme treatment, the fact that the washing step is not included after the enzyme treatment and before the film forming step, and the like. By setting the protein content in the cellulose-containing film to 1 × 10 ^-3 parts by mass or less with respect to 1 part by mass of fibrous cellulose, the optical properties of the cellulose-containing film can be improved.

The haze of the cellulose-containing film of the present invention is preferably less than 2.0%, more preferably less than 1.5%, and even more preferably less than 1.0%. The haze of the cellulose-containing film is a value measured using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute) in accordance with JIS K 7136.

The tensile elastic modulus of the cellulose-containing film of the present invention is preferably 1 GPa or more, more preferably 2 GPa or more, and further preferably 4 GPa or more. The upper limit of the tensile elastic modulus of the cellulose-containing film is not particularly limited, but may be, for example, 50 GPa or less. The tensile elastic modulus of the cellulose-containing film is a value measured using a tensile tester Tensilon (manufactured by A & D Co., Ltd.) in accordance with JIS P 8113. When measuring the tensile elastic modulus, a test piece prepared at 23 ° C. and 50% relative humidity for 24 hours is used as a test piece for measurement, and the measurement is performed under the conditions of 23 ° C. and 50% relative humidity.

The thickness of the cellulose-containing film of the present invention is not particularly limited, but is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. The upper limit of the thickness of the cellulose-containing film is not particularly limited, but can be, for example, 1000 μm or less. The thickness of the cellulose-containing film can be measured with a stylus type thickness gauge (Millitron 1202D manufactured by Marl Co., Ltd.).

The basis weight of the cellulose-containing film of the present invention ^{is preferably 10 g / m 2} or more, more preferably 20 g / m ² or more, and even more preferably 30 g / m ² or more. The basis weight of the cellulose-containing film ^{is preferably 100 g / m 2} or less, and ^{more preferably 80 g / m 2} or less. Here, the basis weight of the cellulose-containing film can be calculated in accordance with JIS P 8124.

(Membrane formation method)
The step of forming the cellulose-containing film includes a step of obtaining a slurry containing fibrous cellulose having a fiber width of 1000 nm or less and a protein, a step of applying this slurry on a substrate, or a step of making a paper. ..

^{In the step of obtaining the slurry, an enzyme of 1 × 10 -3} parts by mass or less may be added to 1 part by mass of the fine fibrous cellulose contained in the slurry.

In the step of obtaining the slurry, it is preferable to further add a hydrophilic polymer. In addition to the hydrophilic polymer, a polyamine polyamide epihalohydrin or a thermoplastic resin such as a polyester resin, an acrylic resin, or a urethane resin may be added. By adding a hydrophilic polymer or the like in this way, a cellulose-containing film having excellent transparency and mechanical strength can be formed. When a hydrophilic polymer or the like is added, the hydrophilic polymer or the like may be added before the enzyme is added to the fine fibrous cellulose.

<Coating process>
The coating step is a step of coating the slurry obtained in the step of obtaining the slurry on the base material and drying the slurry to form a film. The formed cellulose-containing film may be used without peeling from the base material, or may be used as a single sheet by peeling from the base material. By using a coating device and a long base material, a cellulose-containing film can be continuously produced.

The material of the base material used in the coating process is not particularly limited, but a material having high wettability to the composition (slurry) may suppress shrinkage of the cellulose-containing film during drying, but contains cellulose. When the film is peeled off from the base material and used, it is preferable to select one in which the cellulose-containing film formed after drying can be easily peeled off. Of these, a resin film or plate or a metal film or plate is preferable, but is not particularly limited. For example, resin films and plates such as acrylic, polyethylene terephthalate, vinyl chloride, polystyrene, and polyvinylidene chloride, metal films and plates of aluminum, zinc, copper, and iron plates, and those whose surfaces are oxidized, stainless films. And boards, brass films and boards can be used.

In the coating process, when the viscosity of the slurry is low and it develops on the base material, a blocking frame is fixed on the base material to obtain a cellulose-containing film of a predetermined thickness and basis weight. You may. The quality of the dammed frame is not particularly limited, but it is preferable to select one in which the end portion of the cellulose-containing film that adheres after drying can be easily peeled off. Of these, those obtained by molding a resin plate or a metal plate are preferable, but are not particularly limited. For example, resin plates such as acrylic plates, polyethylene terephthalate plates, vinyl chloride plates, polystyrene plates and polyvinylidene chloride plates, metal plates such as aluminum plates, zinc plates, copper plates and iron plates, and those whose surfaces are oxidized, stainless steel. A molded plate, brass plate, or the like can be used.

As the coating machine for coating the slurry, for example, a roll coater, a gravure coater, a die coater, a curtain coater, an air doctor coater and the like can be used. A die coater, a curtain coater, and a spray coater are preferable because the thickness can be made more uniform.

The coating temperature is not particularly limited, but is preferably 20 ° C. or higher and 45 ° C. or lower, more preferably 25 ° C. or higher and 40 ° C. or lower, and further preferably 27 ° C. or higher and 35 ° C. or lower. When the coating temperature is at least the above lower limit value, the slurry can be easily coated, and when it is at least the above upper limit value, volatilization of the dispersion medium during coating can be suppressed.

In the coating step, it is preferable to coat the slurry so that the finished basis weight of the cellulose-containing film is 10 g / m ² or more and 100 g / m ² or less, preferably 20 g / m ² or more and 60 g / m ² or less. By coating so that the basis weight is within the above range, a cellulose-containing film having excellent strength can be obtained.

The coating step preferably includes a step of drying the slurry coated on the substrate. The drying method is not particularly limited, but may be a non-contact drying method or a method of drying while restraining the cellulose-containing membrane, and these may be combined.

The non-contact drying method is not particularly limited, but a method of heating and drying with hot air, infrared rays, far infrared rays or near infrared rays (heat drying method) and a method of vacuum drying (vacuum drying method) are applied. Can be done. The heat drying method and the vacuum drying method may be combined, but the heat drying method is usually applied. Drying with infrared rays, far infrared rays or near infrared rays can be performed using an infrared device, a far infrared device or a near infrared device, but is not particularly limited. The heating temperature in the heat drying method is not particularly limited, but is preferably 20 ° C. or higher and 150 ° C. or lower, and more preferably 25 ° C. or higher and 105 ° C. or lower. When the heating temperature is at least the above lower limit value, the dispersion medium can be rapidly volatilized, and when it is at least the above upper limit value, the cost required for heating can be suppressed and the discoloration of fine fibrous cellulose due to heat can be suppressed. ..

<Papermaking process>
The step of producing the cellulose-containing film may include a step of making a slurry. Examples of the paper machine in the paper making process include continuous paper machines such as a long net type, a circular net type, and an inclined type, and a multi-layer paper making machine combining these. In the papermaking process, known papermaking such as hand-making may be performed.

In the papermaking process, the slurry is filtered on a wire and dehydrated to obtain a cellulose-containing film in a wet paper state, and then pressed and dried to obtain a cellulose-containing film. When the slurry is filtered and dehydrated, the filter cloth for filtration is not particularly limited, but it is important that fine fibrous cellulose and preservatives do not pass through and the filtration rate does not become too slow. Such a filter cloth is not particularly limited, but a sheet made of an organic polymer, a woven fabric, or a porous membrane is preferable. The organic polymer is not particularly limited, but non-cellulosic organic polymers such as polyethylene terephthalate, polyethylene, polypropylene, and polytetrafluoroethylene (PTFE) are preferable. Specific examples thereof include a porous membrane of polytetrafluoroethylene having a pore size of 0.1 μm or more and 20 μm or less, for example, 1 μm, polyethylene terephthalate having a pore size of 0.1 μm or more and 20 μm or less, for example, 1 μm, or a polyethylene woven fabric, but the present invention is not particularly limited.

The method for producing the cellulose-containing film from the slurry is not particularly limited, and examples thereof include a method using the production apparatus described in WO2011 / 013567. This manufacturing equipment discharges a slurry containing fine fibrous cellulose onto the upper surface of an endless belt, and squeezes a dispersion medium from the discharged slurry to generate a web, and a water-squeezed section that dries the web to produce a fiber sheet. It has a drying section to produce. An endless belt is arranged from the watering section to the drying section, and the web generated in the watering section is conveyed to the drying section while being placed on the endless belt.

The dehydration method that can be adopted is not particularly limited, and examples thereof include a dehydration method that is usually used in paper production, and a method of dehydrating with a long net, a circular net, an inclined wire, or the like and then dehydrating with a roll press is preferable. The drying method is not particularly limited, and examples thereof include methods used in the production of paper. For example, a cylinder dryer, a Yankee dryer, hot air drying, a near infrared heater, an infrared heater and the like are preferable.

(Laminated body)
Another layer may be further laminated on the cellulose-containing film obtained in the above-mentioned step to form a laminate. Such other layers may be provided on both surfaces of the cellulose-containing film, but may be provided only on one surface of the cellulose-containing film. Examples of the other layer laminated on at least one surface of the cellulose-containing film include a resin layer and an inorganic layer.

As a specific example of the laminated body, for example,
A laminate in which a resin layer is directly laminated on at least one surface of a cellulose-containing film;
A laminate in which an inorganic layer is directly laminated on at least one surface of a cellulose-containing film;
A laminate in which a resin layer, a cellulose-containing film, and an inorganic layer are laminated in this order;
A laminate in which a cellulose-containing film, a resin layer, and an inorganic layer are laminated in this order; and a laminate in which a cellulose-containing film, an inorganic layer, and a resin layer are laminated in this order:
Can be mentioned.
The layer structure of the laminated body is not limited to the above, and various modes can be used depending on the application.

<Resin layer>
The resin layer is a layer containing a natural resin or a synthetic resin as a main component. Here, the main component refers to a component contained in an amount of 50% by mass or more with respect to the total mass of the resin layer. The content of the resin is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and 90% by mass, based on the total mass of the resin layer. The above is particularly preferable. The resin content may be 100% by mass or 95% by mass or less.

Examples of the natural resin include rosin-based resins such as rosin, rosin ester, and hydrogenated rosin ester.

The synthetic resin is preferably at least one selected from, for example, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polyimide resin, polystyrene resin, polyurethane resin and acrylic resin. Among them, the synthetic resin is preferably at least one selected from the polycarbonate resin and the acrylic resin, and more preferably the polycarbonate resin. The acrylic resin is preferably at least one selected from polyacrylonitrile and poly (meth) acrylate.

Examples of the polycarbonate resin constituting the resin layer include aromatic polycarbonate-based resins and aliphatic polycarbonate-based resins. These specific polycarbonate-based resins are known, and examples thereof include the polycarbonate-based resins described in JP-A-2010-023275.

As the resin constituting the resin layer, one kind may be used alone, or a copolymer obtained by copolymerizing or graft-polymerizing a plurality of resin components may be used. Further, a plurality of resin components may be used as a blend material mixed by a physical process.

An adhesive layer may be provided between the cellulose-containing film and the resin layer, or the adhesive layer may not be provided and the cellulose-containing film and the resin layer may be in direct contact with each other. When an adhesive layer is provided between the cellulose-containing film and the resin layer, examples of the adhesive constituting the adhesive layer include acrylic resins. Examples of the adhesive other than the acrylic resin include vinyl chloride resin, (meth) acrylic acid ester resin, styrene / acrylic acid ester copolymer resin, vinyl acetate resin, and vinyl acetate / (meth) acrylic acid ester. Examples include polymer resins, urethane resins, silicone resins, epoxy resins, ethylene / vinyl acetate copolymer resins, polyester resins, polyvinyl alcohol resins, ethylene vinyl alcohol copolymer resins, and rubber emulsions such as SBR and NBR. Be done.

When the adhesive layer is not provided between the cellulose-containing membrane and the resin layer, the resin layer may have an adhesion aid, or the surface of the resin layer may be surface-treated such as a hydrophilization treatment. good.
Examples of the adhesion aid include a compound containing at least one selected from an isocyanate group, a carbodiimide group, an epoxy group, an oxazoline group, an amino group and a silanol group, and an organic silicon compound. Among them, the adhesion aid is preferably at least one selected from a compound containing an isocyanate group (isocyanate compound) and an organosilicon compound. Examples of the organosilicon compound include a silane coupling agent condensate and a silane coupling agent.
Examples of the surface treatment method other than the hydrophilization treatment include corona treatment, plasma discharge treatment, UV irradiation treatment, electron beam irradiation treatment, flame treatment and the like.

<Inorganic layer>
The substance constituting the inorganic layer is not particularly limited, and is, for example, aluminum, silicon, magnesium, zinc, tin, nickel, titanium; these oxides, carbides, nitrides, oxide carbides, oxide nitrides, or oxide carbide nitrides. Things; or mixtures thereof. From the viewpoint that high moisture resistance can be stably maintained, silicon oxide, silicon nitride, silicon oxide carbide, silicon nitride, silicon oxide, aluminum oxide, aluminum nitride, aluminum oxide carbide, aluminum nitride, or any of these. The mixture is preferred.

The method for forming the inorganic layer is not particularly limited. Generally, the method for forming a thin film is roughly classified into a chemical vapor deposition (CVD) method and a physical vapor deposition method (PVD), and any method may be adopted. .. Specific examples of the CVD method include plasma CVD using plasma, catalytic chemical vapor deposition (Cat-CVD) in which a material gas is catalytically pyrolyzed using a heating catalyst, and the like. Specific examples of the PVD method include vacuum deposition, ion plating, and sputtering.

Further, as a method for forming the inorganic layer, an atomic layer deposition method (ALD) can also be adopted. The ALD method is a method of forming a thin film in atomic layer units by alternately supplying the raw material gas of each element constituting the film to be formed to the surface on which the layer is formed. Although it has the disadvantage of a slow film formation rate, it has the advantage of being able to cleanly cover even a surface having a complicated shape and forming a thin film with few defects, as compared with the plasma CVD method. Further, the ALD method has an advantage that the film thickness can be controlled on the nano-order and it is relatively easy to cover a wide surface. Furthermore, the ALD method can be expected to improve the reaction rate, lower the temperature process, and reduce the amount of unreacted gas by using plasma.

(Use)
The cellulose-containing composition of the present invention can be mixed with, for example, a paint, a resin, an emulsion, a hydraulic material (cement), or rubber and used as a reinforcing material. A cellulose-containing film may be produced by forming a film using the slurry of the cellulose-containing composition of the present invention. The cellulose-containing composition of the present invention can also be used for various purposes as a thickener.

Cellulose-containing films are suitable for use in light-transmitting substrates such as various display devices, various solar cells, and the like. It is also suitable for applications such as substrates for electronic devices, materials for home appliances, window materials for various vehicles and buildings, interior materials, exterior materials, and packaging materials. Further, in addition to threads, filters, woven fabrics, cushioning materials, sponges, abrasives, etc., it is also suitable for applications in which the cellulose-containing film itself is used as a reinforcing material.

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

[Example 1]
<Preparation of phosphoric acid group-introduced fibrous cellulose>
As the raw material pulp, softwood kraft pulp made by Oji Paper (solid content 93% by mass, basis weight 208 g / m2 sheet, disintegrated and measured according to JIS P 8121 has a Canadian standard drainage degree (CSF) of 700 ml). used.
The raw material pulp was phosphorylated as follows.
First, a mixed aqueous solution of ammonium dihydrogen phosphate and urea is added to 100 parts by mass (absolute dry mass) of the raw material pulp to obtain 45 parts by mass of ammonium dihydrogen phosphate, 120 parts by mass of urea, and 150 parts by mass of water. To obtain a chemical-impregnated pulp. Next, the obtained chemical-impregnated pulp was heated in a hot air dryer at 165 ° C. for 200 seconds to introduce a phosphoric acid group into the cellulose in the pulp to obtain a phosphorylated pulp.

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

Next, the phosphorylated pulp after washing was subjected to alkali treatment as follows.
First, the washed phosphorylated pulp was diluted with 10 L of ion-exchanged water, and then a 1N aqueous sodium hydroxide solution was added little by little with stirring to obtain a phosphorylated pulp slurry having a pH of 12 or more and 13 or less. .. Then, the phosphorylated pulp slurry was dehydrated to obtain an alkali-treated phosphorylated pulp.
Next, the phosphorylated pulp after the alkali treatment was subjected to the above cleaning treatment.

The infrared absorption spectrum of the phosphorylated pulp thus obtained was measured using FT-IR. As a result, absorption based on the phosphate group was observed around 1230 cm-1, and it was confirmed that the phosphate group was added to the pulp. The amount of phosphoric acid group (strong acid group amount) measured by the measuring method described later was 1.45 mmol / g.

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

<Fiber processing>
Ion-exchanged water was added to the obtained phosphorylated pulp to prepare a slurry having a solid content concentration of 2% by mass.
This slurry was treated four times at a pressure of 200 MPa with a wet atomizing device (Starburst, manufactured by Sugino Machine Limited) to obtain a fine fibrous cellulose dispersion A containing fine fibrous cellulose.
By X-ray diffraction, it was confirmed that this fine fibrous cellulose maintained the cellulose type I crystal.
Moreover, when the fiber width of the fine fibrous cellulose was measured using a transmission electron microscope, it was 3 to 5 nm.

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

<Measurement of fiber width>
The fiber width of the fine fibrous cellulose was measured by the following method.
The supernatant of the fine fibrous cellulose dispersion obtained by treatment with a wet atomizing device is mixed with water so that the concentration of the fine fibrous cellulose is 0.01% by mass or more and 0.1% by mass or less. It was added dropwise to the diluted and hydrophilized carbon grid film. This was dried, stained with uranyl acetate, and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.).

<Enzyme treatment>
^{In the fine fibrous cellulose dispersion A, 3.0 × 10-6} mass of an enzyme-containing liquid (manufactured by AB Enzymes, ECOPULP R, enzyme content is about 5% by mass) with respect to 1 part by mass of the fine fibrous cellulose. Partially added, and the mixture was stirred at 18,500 rpm for 2 minutes. This was recovered to obtain a slurry for evaluation.

[Example 2]
In <enzyme treatment> of Example 1, 1.0 × ^10-2 parts by mass of an enzyme-containing liquid was added to 1 part by mass of fine fibrous cellulose. Other procedures were the same as in Example 1 to obtain an evaluation slurry.

[Example 3]
In <enzyme treatment> of Example 1, 1.0 × ^10-5 parts by mass of an enzyme-containing liquid was added to 1 part by mass of fine fibrous cellulose. Other procedures were the same as in Example 1 to obtain an evaluation slurry.

[Example 4]
In <enzyme treatment> of Example 1, 4.76 × ^10-5 parts by mass of an enzyme-containing liquid was added to 1 part by mass of fine fibrous cellulose. Other procedures were the same as in Example 1 to obtain an evaluation slurry.

[Example 5]
In Example 4, instead of the fine fibrous cellulose dispersion A, the fine fibrous cellulose dispersion B described later was used. Other procedures were the same as in Example 4 to obtain an evaluation slurry. The fine fibrous cellulose dispersion B was produced by the following method.

<TEMPO oxidation>
As the raw material pulp, softwood kraft pulp (undried) made by Oji Paper was used.
Alkaline TEMPO oxidation treatment was carried out on this raw material pulp as follows.
First, the above-mentioned raw material pulp equivalent to 100 parts by mass of dry mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl), and 10 parts by mass of sodium bromide are added to 10000 parts by mass of water. It was dispersed in the parts. Then, 13% by mass sodium hypochlorite aqueous solution was added to 1.0 g of pulp so as to be 3.8 mmol, and the reaction was started. During the reaction, a 0.5 M aqueous sodium hydroxide solution was added dropwise to keep the pH at 10 or more and 10.5 or less, and the reaction was considered to be completed when no change was observed in the pH.

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

The dehydrated sheet corresponding to 100 parts by mass of dry mass was dispersed in 10000 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 then reacted at room temperature for 48 hours with stirring at 500 rpm using a magnetic stirrer to obtain a pulp slurry.

Next, the obtained top-oxidized TEMPO oxide pulp was washed.
The washing treatment is carried out by dehydrating the pulp slurry after the additional oxidation to obtain a dehydrated sheet, pouring 5000 parts by mass of ion-exchanged water, stirring and uniformly dispersing the pulp slurry, and then repeating the operation of filtering and dehydrating. rice field. When the electrical conductivity of the filtrate became 100 μS / cm or less, the washing end point was set. With respect to the TEMPO oxidized pulp thus obtained, the amount of carboxyl groups measured by the measuring method described later was 1.30 mmol / g.
Further, when the obtained TEMPO oxide pulp was tested and analyzed by an X-ray diffractometer, it was found at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less. A typical peak was confirmed, and it was confirmed that it had cellulose type I crystals.

<Fiber processing>
Ion-exchanged water was added to the obtained dehydrated sheet to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated four times at a pressure of 200 MPa with a wet atomizing apparatus (manufactured by Sugino Machine Limited, Starburst) to obtain a fine fibrous cellulose dispersion B.

<Measurement of carboxyl group amount>
The amount of carboxyl group of the fine fibrous cellulose is adjusted to 0.2% by mass by adding ion-exchanged water to the fine fibrous cellulose-containing slurry containing the target fine fibrous cellulose, and treated with an ion-exchange resin. After that, it was measured by performing a titration using an alkali.
The treatment with an ion exchange resin is carried out by adding a 1/10 volume of strongly acidic ion exchange resin (Amberjet 1024; manufactured by Organo Corporation, conditioned) to a slurry containing 0.2% by mass of fine fibrous cellulose for 1 hour. After the shaking treatment, the resin and the slurry were separated by pouring onto a mesh having a mesh size of 90 μm.
For titration using alkali, change in the value of electrical conductivity indicated by the slurry is measured while adding a 0.1 N sodium hydroxide aqueous solution to the fine fibrous cellulose-containing slurry after treatment with an ion exchange resin. Was done by. For the amount of carboxyl groups (mmol / g), the amount of alkali (mmol) required in the region corresponding to the first region shown in FIG. 2 of the measurement results is divided by the solid content (g) in the slurry to be titrated. Calculated.

[Comparative Example 1]
In Example 1, <enzyme treatment> was not performed. A slurry for evaluation was obtained in the same manner as in Example 1 except for the above.

[Comparative Example 2]
<Enzyme treatment>
The phosphorylated pulp obtained in <Preparation of Phosphate Group-Introduced Fibrous Cellulose> in Example 1 after the alkali treatment and washing treatment was diluted to 2% with ion-exchanged water, and then an enzyme-containing liquid was added. ^{The amount of the enzyme-containing liquid added was 4.76 × 10-5} parts by mass with respect to 1 part by mass of the solid content. Next, the phosphorylated pulp was allowed to stand in an environment of 25 ° C. for 24 hours, dehydrated to obtain a dehydrated sheet, and then 5000 parts by mass of ion-exchanged water was poured, stirred and uniformly dispersed. It was filtered and dehydrated. Then, 5000 parts by mass of ion-exchanged water was poured again, and the mixture was stirred and uniformly dispersed, and then filtered and dehydrated.

Regarding the phosphorylated pulp after the filtration dehydration, the amount of phosphoric acid groups (strong acid group amount) measured by the above method was 1.45 mmol / g. Further, when the analysis was performed by an X-ray diffractometer, typical peaks were confirmed at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less, and cellulose type I. It was confirmed that it had crystals.

<Fiber processing>
Ion-exchanged water was added to the obtained phosphorylated pulp to prepare a slurry having a solid content concentration of 2% by mass.
This slurry was treated four times at a pressure of 200 MPa with a wet atomizer (Starburst, manufactured by Sugino Machine Limited) to obtain an evaluation slurry containing fine fibrous cellulose.
By X-ray diffraction, it was confirmed that this fine fibrous cellulose maintained the cellulose type I crystal.
Further, the fiber width of the fine fibrous cellulose was measured by the method using the above-mentioned transmission electron microscope and found to be 3 to 5 nm.

[Comparative Example 3]
In Example 5, the alkali-treated and washed-treated TEMPO-oxidized pulp obtained through <TEMPO oxidation> was diluted to 2% with ion-exchanged water, and then the enzyme-containing liquid was added. ^{The amount of the enzyme-containing liquid added was 4.76 × 10-5} parts by mass with respect to 1 part by mass of the solid content. Next, the TEMPO oxidized pulp was allowed to stand in an environment of 25 ° C. for 24 hours, dehydrated to obtain a dehydrated sheet, and then 5000 parts by mass of ion-exchanged water was poured, stirred and uniformly dispersed. It was filtered and dehydrated. Then, 5000 parts by mass of ion-exchanged water was poured again, and the mixture was stirred and uniformly dispersed, and then filtered and dehydrated.

The amount of carboxyl groups (strong acid group amount) measured by the above method for the TEMPO oxidized pulp after the filtration dehydration was 1.30 mmol / g. Further, when the analysis was performed by an X-ray diffractometer, typical peaks were confirmed at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less, and cellulose type I crystals. It was confirmed that it had.

<Fiber processing>
Ion-exchanged water was added to the obtained dehydrated sheet to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated four times at a pressure of 200 MPa with a wet atomizer (Starburst, manufactured by Sugino Machine Limited) to obtain an evaluation slurry containing fine fibrous cellulose. By X-ray diffraction, it was confirmed that this fine fibrous cellulose maintained the cellulose type I crystal. Further, the fiber width of the fine fibrous cellulose was measured by the method using the above-mentioned transmission electron microscope and found to be 3 to 5 nm.

[Comparative Example 4]
In Comparative Example 3, the amount of the enzyme-containing liquid added was 1.0 × 10 ^{-1 part by} mass with respect to 1 part by mass of the solid content. A slurry for evaluation was obtained in the same manner as in Comparative Example 3 except for the above.

[Comparative Example 5]
In Example 1, 1 part by mass of the enzyme-containing liquid was added to 1 part by mass of the fine fibrous cellulose. A slurry for evaluation was obtained in the same manner as in Example 1 except for the above.

<Measurement>
The evaluation slurries obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were used for measurement according to the following method.

[viscosity]
Twenty-four hours after the production of the evaluation slurry, ion-exchanged water was poured to prepare the solid content concentration to 0.4% by mass. Then, the mixture was allowed to stand in an environment of 25 ° C. for 24 hours, and then using a B-type viscometer (No. 3 rotor) (analog viscometer T-LVT manufactured by BLOOKFIELD) at 25 ° C. at a rotation speed of 3 rpm for 3 minutes. The viscosity was measured by rotating.

[Degree of polymerization]
The evaluation of the average degree of polymerization of the cellulose molecules constituting the fine fibrous cellulose was carried out with reference to the following paper.
TAPPI International Standard; ISO / FDIS 5351, 2009.
Smith, DK; Bampton, RF; Alexander, WJ Ind. Eng. Chem., Process Des. Dev. 1963, 2, 57-62.

30 g of a suspension obtained by diluting the target fine fibrous cellulose with ion-exchanged water so that the content is 2 ± 0.3% by mass is divided into a centrifuge tube, allowed to stand overnight in a freezer, and frozen. I let you. Further, it was dried in a freeze dryer for 5 days or more, and then heated in a constant temperature dryer set at 105 ° C. for 3 hours or more and 4 hours or less to obtain fine fibrous cellulose in an absolutely dry state.
To measure the reference, 15 ml of pure water and 15 ml of 1 mol / L copper ethylenediamine were added to an empty screw tube having a capacity of 50 ml to prepare a 0.5 mol / L copper ethylenediamine solution. 10 ml of the above 0.5 mol / L copper ethylenediamine solution was placed in a Canon Fenceke viscometer, left for 5 minutes, and then the drop time at 25 ° C. was measured to determine the solvent drop time.

Next, in order to measure the viscosity of the fine fibrous cellulose, 0.14 g or more and 0.16 g or less of the absolutely dry fine fibrous cellulose was weighed into an empty 50 ml capacity screw tube, and 15 ml of pure water was added. Further, 15 ml of 1 mol / L copper ethylenediamine was added, and the mixture was stirred with a rotating and revolving supermixer at 1000 rpm for 10 minutes to prepare a 0.5 mol / L copper ethylenediamine solution. In the same manner as in the reference measurement, 10 ml of the prepared 0.5 mol / L copper ethylenediamine solution was placed in a Canon Fenceke viscometer, left for 5 minutes, and then the drop time at 25 ° C. was measured. The fall time was measured three times, and the average value was taken as the fall time of the fine fibrous cellulose solution.

The degree of polymerization was calculated from the mass of the absolutely dry fine fibrous cellulose used for the measurement, the solvent drop time, and the fall time of the fine fibrous cellulose solution using the following formula. The average degree of polymerization below is the average value of the values measured three times.
Absolutely dry fine fibrous cellulose mass used for measurement: a (g) (where a is 0.14 or more and 0.16 or less)
Cellulose concentration in solution: c = a / 30 (g / mL)
Solvent drop time: t ₀ (sec)
Falling time of fine fibrous cellulose solution: t (sec)
Relative viscosity of solution: η _rel = t / t ₀
Specific viscosity of solution: η _sp = η _rel- 1
Intrinsic viscosity: [η] = η _{sp /} c (1 + 0.28 _{η sp} )
Degree of polymerization: DP = [η] /0.57

[Endoglucanase (EG) activity]
The EG activity of the evaluation slurry was measured and defined as follows.
A substrate solution (concentration 100 mM, containing a pH 5.0 sodium acetate-sodium acetate buffer) of carboxyl methyl cellulose (CMCNa High Viscosity: Cat No. 150561, MP Biomedicals, Inc.) at a concentration of 1% (W / V) was prepared. Immediately after production, the evaluation slurry was diluted with a buffer solution (similar to the above) in advance (the dilution ratio was such that the absorbance of the enzyme solution below was within the calibration curve obtained from the glucose standard solution below). To 90 μl of the substrate solution, 10 μl of the diluted evaluation slurry solution was added and reacted at 37 ° C. for 30 minutes.

To prepare a calibration curve, select ion-exchanged water (blank) and glucose standard solution (4 standard solutions with at least different concentrations from 0.5 to 5.6 mM), prepare 100 μl each, and prepare at 37 ° C. It was kept warm for 30 minutes.
300 μl of DNS color-developing solution (1.6% by mass NaOH, 1% by mass 3,5-dinitrosalicylic acid, 30% by mass, respectively, in the slurry solution for enzyme-containing evaluation after the reaction, the blank for the calibration line, and the glucose standard solution. (Potassium tartrate) was added and boiled for 5 minutes to develop color. Immediately after color development, the mixture was ice-cooled, 2 ml of ion-exchanged water was added, and the mixture was mixed well. After allowing to stand for 30 minutes, the absorbance was measured within 1 hour.

For the measurement of the absorbance, 200 μl was dispensed into a 96-well microwell plate (269620, manufactured by NUNC), and the absorbance at 540 nm was measured using a microplate reader (infiniteM200, manufactured by TECAN).

A calibration curve was prepared using the absorbance and glucose concentration of each glucose standard solution minus the absorbance of the blank. The amount of glucose equivalent produced in the evaluation slurry solution was calculated by subtracting the blank absorbance from the absorbance of the evaluation slurry solution and then using a calibration curve (if the absorbance of the evaluation slurry solution does not enter the calibration curve, the buffer solution is described above. Remeasure by changing the dilution ratio when diluting the evaluation slurry in.) The amount of enzyme that produces 1 μmol of reducing sugar equivalent to glucose in 1 minute was defined as 1 unit, and the EG activity was calculated from the following formula.
EG activity = Glucose equivalent production amount (μmol) / 30 minutes x dilution ratio of 1 ml of evaluation sample solution obtained by diluting with buffer solution [Fukui Sakuzo, "Biochemical Experiment Method (Quantitative Method of Reduced Sugar) Second Edition"", Society Publishing Center, pp. 23-24 (1990)]

The same measurement was performed 24 hours after the evaluation slurry was produced.
In all the examples, the EG activity did not change between the evaluation slurry immediately after the addition of the enzyme and the evaluation slurry 24 hours after the evaluation slurry was produced.

[Protein content]
The protein contained in the evaluation slurry was determined by the burette method.
Pure water was added to bovine serum albumin to prepare the protein so that the mass% of the protein was 5.0% or less.
To the bovine serum albumin solution prepared above, 4 times the amount of the burette drug was added, mixed well, and left to stand in an environment of 20 ° C. to 25 ° C. for 30 minutes. Then, the absorption wavelength of 540 nm was measured using a spectrophotometer. A calibration curve was drawn based on the measured values.
Next, the evaluation slurry was separated, 4 times the amount of the burette reagent was added, mixed well, and left to stand in an environment of 20 ° C. to 25 ° C. for 30 minutes. Then, the absorption wavelength of 540 nm was measured using a spectrophotometer. The measured value was written on the calibration curve to determine the amount of protein contained in the evaluation slurry.

<Evaluation>
The evaluation slurries obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated according to the following methods.

[Optical characteristics of cellulose-containing film]
The evaluation slurries obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were used to form a cellulose-containing film, and the haze was measured. The method for forming the cellulose-containing film will be described later.
The haze was measured using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute) in accordance with JIS K 7136. In the evaluation results of the examples, if the haze is less than 1.0%, it is indicated as ⊚, if it is less than 1.5%, it is indicated as ○, if it is less than 2.0%, it is indicated as Δ, and if it is 2.0% or more, it is indicated as ×. ..

Method of forming cellulose-containing film:
The concentration of the evaluation slurry was adjusted by adding ion-exchanged water so that the solid content concentration was 1.0% by mass.
Next, 100 parts by mass of a water-soluble polyester resin (manufactured by Reciprocal Chemical Co., Ltd., plus coat Z-221, solid content concentration is 20% by mass) was added to 100 parts by mass of this fine fibrous cellulose dispersion to prepare a coating composition. I got A.
Next, the coating liquid is weighed so that the finished basis weight of the obtained coating film (composed of the solid content of the coating composition A) is 50 g / m2, and the coating film is applied to a commercially available acrylic plate at 50 ° C. , It was dried in a constant temperature and humidity chamber having a relative humidity of 15%. A metal frame for damming (a gold frame having an inner dimension of 180 mm × 180 mm) was placed on the acrylic plate so as to have a predetermined basis weight. The coating film formed after drying was peeled off from the acrylic plate to obtain a coating film (cellulose-containing film) having a thickness of 37 μm containing fine fibrous cellulose.

[Mechanical characteristics of cellulose-containing membrane]
The tensile elastic modulus was measured using the cellulose-containing film obtained in the above [Optical properties of the cellulose-containing film].
The tensile elastic modulus was measured using a tensile tester Tensilon (manufactured by A & D Co., Ltd.) in accordance with JIS P 8113 except that the length of the test piece was 80 mm and the distance between chucks was 50 mm. When measuring the tensile elastic modulus, a test piece prepared at 23 ° C. and 50% relative humidity for 24 hours was used as a test piece, and the measurement was performed under the conditions of 23 ° C. and 50% relative humidity. In the evaluation results of the examples, if the tensile elastic modulus is 4 GPa or more, it is marked as ⊚, if it is 2 GPa or more, it is marked as ◯, if it is 1 GPa or more, it is marked as Δ, and if it is less than 1 GPa, it is marked as ×.

[Applicability when forming a cellulose-containing film]
A water-soluble polyester resin (manufactured by Reciprocal Chemical Co., Ltd., Pluscoat Z-221, solid content concentration: 20% by mass) was added to 100 parts by mass of the evaluation slurry obtained in Examples 1 to 5 and Comparative Examples 1 to 5. 100 parts by mass was added to obtain a coating composition B. Next, this coating composition B was applied onto a polycarbonate film (Teijin Co., Ltd., Panlite PC-2151, thickness 300 μm) using a film applicator to form a wet film. The coating width of the film applicator was 150 mm, and the gap (coating thickness) was 3 mm. A sensory evaluation was performed on the coating suitability when coating the evaluation slurry. When visually checking the wet film, ◎ if no unevenness is seen, ○ if some unevenness is seen, △ if noticeable unevenness is seen, × if continuous wet film cannot be formed due to unevenness. Notated.

As is clear from Table 1, in Examples 1 to 5 in which the protein content and the endoglucanase activity are in a preferable range, the optical and mechanical properties of the film are good, and the coating suitability is also good. An excellent evaluation slurry was obtained.
On the other hand, as is clear from Table 2, in Comparative Example 1 in which the enzyme was not added, the coating suitability was inferior. Further, in Comparative Examples 2 to 4, after the pulp was treated with an enzyme, the enzyme was washed with ion-exchanged water, but even in such a case, the protein content and the endoglucanase activity were low and the pulp was coated. The result was that the workability was inferior. Further, in Comparative Example 5 in which the protein content and the endoglucanase activity were higher than the preferable ranges, the optical properties of the film were poor.

Claims (5)

A cellulose-containing composition containing a fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the fibrous cellulose has a phosphate group or an ionic substituent derived from the phosphate group, and the protein is cellulase. The content of the protein, which is at least one of the system enzyme or the inactivated cellulase system enzyme and is the total content of the enzyme and the inactivated enzyme, is 1 × with respect to 1 part by mass of the fibrous cellulose. The ^{viscosity is 10-7} parts by mass or more and 1 × 10 ^-3 parts by mass or less, and the viscosity measured under the conditions of 25 ° C. and 3 rpm with the solid content concentration of the fibrous cellulose being 0.4% by mass is 10 mPa · s or more and 11000 mPa. -A cellulose-containing composition having an s or less. A cellulose-containing composition containing fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the fibrous cellulose has a phosphoric acid group or an ionic substituent derived from the phosphoric acid group, and is a cellulose-containing composition. The content of the fibrous cellulose with respect to the total solid content of is 0.5% by mass or more and 95% by mass or less, and the protein is at least one of a cellulase-based enzyme or an inactivated cellulase-based enzyme, and the end of the enzyme. The glucanase activity is 0.084 U / L or more and 840 U / L or less, and the viscosity measured under the conditions of 25 ° C. and 3 rpm with the solid content concentration of the fibrous cellulose being 0.4% by mass is 10 mPa · s or more and 11000 mPa ·. Cellulose-containing composition which is s or less. The cellulose-containing composition according to claim 1 or 2, wherein the degree of polymerization of the fibrous cellulose is 200 or more and 450 or less. A film containing a fibrous cellulose having a fiber width of 1000 nm or less and a protein, wherein the fibrous cellulose has a phosphate group or an ionic substituent derived from the phosphate group, and the protein is a cellulase-based enzyme. Alternatively, the content of the protein, which is at least one of the inactivated cellulase-based enzymes and is the total content of the enzyme and the inactivated enzyme, is 1 × ^{10-7 with respect to 1 part by mass of the fibrous cellulose.} A film having a mass of parts or more and 1 × 10 to ³ parts by mass or less. ^{1 × 10 -7} parts by mass or more and 1 × 10 ^-3 parts by mass or less with respect to 1 part by mass of fibrous cellulose having a phosphoric acid group or an ionic substituent derived from a phosphoric acid group and having a fiber width of 1000 nm or less. A method for producing a cellulosic-containing composition containing fibrous cellulose, which comprises a step of adding a cellulase-based enzyme of the above.
The viscosity of the cellulose-containing composition measured under the conditions of 25 ° C. and 3 rpm with the solid content concentration of the fibrous cellulose being 0.4% by mass is 10 mPa · s or more and 11000 mPa · s or less.
The manufacturing method.

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