JP7412902B2 - Additives containing carboxymethylated cellulose nanofibers - Google Patents

Description

The present invention relates to additives containing carboxymethylated cellulose nanofibers. In particular, the present invention relates to an additive containing carboxymethylated cellulose nanofibers that have a specific range of carboxymethyl substitution degree and cellulose type I crystallinity, and exhibit high transparency when dispersed in water.

Carboxymethylated cellulose is a derivative of cellulose, and has carboxymethyl groups bonded to some of the hydroxyl groups in the glucose residues that constitute the cellulose skeleton. Carboxymethylated cellulose is used as various additives such as thickeners, binders, binders, water absorbing materials, water retaining materials, and emulsion stabilizers in cosmetics, pharmaceuticals, foods, and various industrial products. Carboxymethylated cellulose is an environmentally friendly material that is slowly biodegradable because it is derived from natural cellulose and can be disposed of by incineration, and its uses are expected to expand in the future.

The method for producing carboxymethylated cellulose is generally to treat cellulose with an alkali (mercerization) and then to treat it with an etherification agent (also called carboxymethylation agent) (carboxymethylation, also called etherification). Methods are known, including a method in which both mercerization and carboxymethylation are performed using water as a solvent, and a method in which both mercerization and carboxymethylation are performed in a solvent mainly composed of an organic solvent (Patent Document 1). The former is called the "aqueous method" and the latter is called the "solvent method."

In carboxymethylated cellulose, when the amount of carboxymethyl groups increases (ie, when the degree of carboxymethyl substitution increases), carboxymethylated cellulose becomes soluble in water. On the other hand, by adjusting the degree of carboxymethyl substitution to an appropriate range, the fibrous shape of carboxymethylated cellulose can be maintained even in water. Carboxymethylated cellulose having a fibrous shape can be converted into nanofibers having a nanoscale fiber diameter by mechanically defibrating it (Patent Document 2).

Japanese Patent Application Publication No. 2017-149901 International Publication No. 2014/088072

Carboxymethylated cellulose is used as an additive in various fields such as food and beverages, cosmetics, and water-based paints because of its properties such as thickening, water absorption, and water retention. Furthermore, carboxymethylated cellulose nanofibers made from carboxymethylated cellulose are also expected to be used as additives in various fields.

However, cellulose nanofibers obtained by defibrating carboxymethylated cellulose obtained by a conventional solvent method have low transparency when made into an aqueous dispersion, and the range of use as an additive is limited. In addition, cellulose nanofibers obtained by fibrillation of carboxymethylated cellulose obtained by the water-based method require the use of large amounts of chemicals such as mercerizing agents and carboxymethylating agents in order to increase transparency, and the manufacturing process is difficult. It was a project that posed major financial and financial challenges.

An object of the present invention is to provide an additive containing carboxymethylated cellulose nanofibers that forms a highly transparent aqueous dispersion.

As a result of intensive studies for the above-mentioned purpose, the present inventors conducted mercerization (alkali treatment of cellulose) in a solvent mainly composed of water, and then carried out carboxymethylation ( (Also called etherification) in a mixed solvent of water and an organic solvent, it is possible to perform etherification in a mixed solvent of water and an organic solvent. Compared to carboxymethylated cellulose obtained using a method in which both carboxymethylation and carboxymethylation are carried out in an organic solvent It has been found that it can be economically produced with a high effective utilization rate of the agent. In addition, this additive containing carboxymethylated cellulose nanofibers is homogeneous, has excellent dispersion stability, has excellent water retention and shape retention, and is relatively less sticky and smooth when it comes in contact with water. It has been found that the present invention does not easily form lumps in water, provides a transparent aqueous dispersion, and can be suitably used in various fields.

The present invention includes, but is not limited to, the following:
(1) Cellulose type I has a crystallinity of 60% or more, a degree of carboxymethyl substitution of 0.50 or less, and light with a wavelength of 660 nm when made into an aqueous dispersion with a solid content of 1% (w/v). An additive containing carboxymethylated cellulose nanofibers having a transmittance of 70% or more.
(2) Carboxymethyl produced by performing a mercerization reaction on carboxymethylated cellulose nanofibers in a solvent mainly composed of water, and then a carboxymethylation reaction in a mixed solvent of water and an organic solvent. The additive according to (1), which is obtained by defibrating cellulose.
(3) The additive according to (2), wherein the water-based solvent is a solvent containing more than 50% by mass of water.
(4) The additive according to any one of (1) to (3), wherein the carboxymethylated cellulose nanofibers have an average fiber diameter of 3 nm to 500 nm.
(5) The additive according to any one of (1) to (4), which is a cosmetic additive.
(6) The additive according to any one of (1) to (4), which is a food additive.
(7) The additive according to any one of (1) to (4), which is an additive for pharmaceuticals or quasi-drugs.
(8) The additive according to any one of (1) to (4), which is a feed additive.
(9) The additive according to any one of (1) to (4), which is a papermaking additive.
(10) The additive according to any one of (1) to (4), which is an additive for paint.
(11) The additive according to any one of (1) to (4), which is a water retention agent.
(12) The additive according to any one of (1) to (4), which is a shape retention imparting agent.
(13) The additive according to any one of (1) to (4), which is a viscosity modifier.
(14) The additive according to any one of (1) to (4), which is an emulsion stabilizer or a dispersion stabilizer.

The additive of the present invention is homogeneous, has excellent dispersion stability, has excellent water retention and shape retention properties, and is relatively less sticky and smooth when it comes into contact with water, and does not form lumps in water. Because it is difficult to form and provides a highly transparent aqueous dispersion, it is used as a water retention agent, shape retention agent, viscosity modifier, and emulsion stabilizer in various fields such as food, medicine, cosmetics, feed, paper manufacturing, and paints. It can be suitably used as various additives such as , dispersion stabilizer and the like.

<Carboxymethylated cellulose nanofiber>
The present invention is characterized in that the degree of carboxymethyl substitution is 0.50 or less, the crystallinity of cellulose I type is 60% or more, and the wavelength when made into an aqueous dispersion with a solid content of 1% (w/v) The present invention relates to an additive containing carboxymethylated cellulose nanofibers having a transmittance of 660 nm light of 70% or more. Carboxymethylated cellulose has a structure in which some of the hydroxyl groups in glucose residues constituting cellulose are ether bonded to carboxymethyl groups.

Carboxymethylated cellulose nanofibers refer to carboxymethylated cellulose having the above structure converted into nanofibers having a nanoscale fiber diameter. Carboxymethylated cellulose may take the form of a salt such as a metal salt such as a sodium salt of carboxymethylated cellulose, and carboxymethylated cellulose nanofibers may also take the form of a salt.

The carboxymethylated cellulose nanofibers of the present invention maintain at least a portion of their fibrous shape even when dispersed in water. That is, when an aqueous dispersion of carboxymethylated cellulose nanofibers is observed with an electron microscope, a fibrous substance can be observed. Furthermore, when carboxymethylated cellulose nanofibers are measured by X-ray diffraction, the peak of cellulose type I crystals can be observed.

<Crystallinity of cellulose type I>
The crystallinity of cellulose in the carboxymethylated cellulose nanofibers used in the present invention is 60% or more for crystal type I, preferably 65% or more. When cellulose type I has a high crystallinity of 60% or more, the proportion of cellulose that maintains a crystalline structure without dissolving in water or other solvents is high, resulting in high thixotropy (thixotropy) and the use of thickeners, etc. This makes it suitable for viscosity adjustment applications. Further, for example, but not limited to this, when added to gel-like substances (for example, foods, cosmetics, etc.), there is an advantage that excellent shape retention can be imparted. The crystallinity of cellulose can be controlled by the concentration of the mercerizing agent, the temperature during treatment, and the degree of carboxymethylation. Since a high concentration of alkali is used in mercerization and carboxymethylation, type I crystals of cellulose are easily converted to type II, but modification can be prevented by adjusting the amount of alkali (mercerization agent) used. By adjusting the degree, desired crystallinity can be maintained. The upper limit of the crystallinity of cellulose type I is not particularly limited. In reality, the upper limit is considered to be about 90%.

The method for measuring the crystallinity of cellulose type I of carboxymethylated cellulose nanofibers is as follows:
The sample is placed on a glass cell and measured using an X-ray diffraction measuring device (LabX XRD-6000, manufactured by Shimadzu Corporation). The crystallinity was calculated using the method of Segal et al. Using the diffraction intensity of 2θ = 10° to 30° in the X-ray diffraction diagram as the baseline, the diffraction intensity of the 002 plane at 2θ = 22.6° and 2θ = It is calculated from the diffraction intensity of the amorphous portion at 18.5° using the following formula.

Xc=(I002c−Ia)/I002c×100
Xc = crystallinity of cellulose type I (%)
I002c: 2θ=22.6°, diffraction intensity of the 002 plane Ia: 2θ=18.5°, diffraction intensity of the amorphous part.

The proportion of type I crystals in carboxymethylated cellulose nanofibers is usually the same as that in carboxymethylated cellulose before it is made into nanofibers.
<Carboxymethyl substitution degree>
The carboxymethylated cellulose nanofibers used in the present invention have a degree of carboxymethyl substitution per anhydroglucose unit of cellulose of 0.50 or less. It is considered that if the degree of carboxymethyl substitution exceeds 0.50, it will dissolve in water and the fiber shape will not be maintained. In consideration of operability, the degree of substitution is preferably 0.02 to 0.50, more preferably 0.05 to 0.50, even more preferably 0.10 to 0.40, More preferably, it is 0.20 to 0.40. By introducing carboxymethyl groups into cellulose, the cellulose particles electrically repel each other, making it possible to defibrate them into nanofibers, but when the degree of carboxymethyl substitution per anhydroglucose unit is lower than 0.02 If it is small, defibration may be insufficient and highly transparent cellulose nanofibers may not be obtained. In addition, in the conventional aqueous method, it is difficult to obtain carboxymethylated cellulose nanofibers with a cellulose type I crystallinity of 60% or more when the degree of carboxymethyl substitution is in the range of 0.20 to 0.40. However, the present inventors, for example, by the method described below, obtained carboxymethylated cellulose in which the degree of carboxymethyl substitution is in the range of 0.20 to 0.40 and the degree of crystallinity of cellulose I type is 60% or more. We have discovered that cellulose nanofibers can be produced. The degree of carboxymethyl substitution can be adjusted by controlling the amount of carboxymethylating agent to be reacted, the amount of mercerizing agent, and the composition ratio of water and organic solvent.

In the present invention, anhydroglucose units refer to individual anhydroglucoses (glucose residues) that constitute cellulose. In addition, the degree of carboxymethyl substitution (also referred to as the degree of etherification) refers to the proportion of hydroxyl groups in glucose residues constituting cellulose that are substituted with carboxymethyl ether groups (carboxymethyl per one glucose residue). number of ether groups). Note that the degree of carboxymethyl substitution may be abbreviated as DS.

The method for measuring the degree of carboxymethyl substitution is as follows:
Weigh approximately 2.0 g of the sample accurately and place it in a 300 mL Erlenmeyer flask with a stopper. Add 100 mL of a solution prepared by adding 100 mL of special grade concentrated nitric acid to 1000 mL of methanol nitric acid, and shake for 3 hours to convert carboxymethylated cellulose nanofiber salt (CMC) to H-CMC (hydrogen-type carboxymethylated cellulose nanofiber). . Accurately weigh 1.5 to 2.0 g of the bone-dried H-CMC and place it in a 300 mL Erlenmeyer flask with a stopper. Wet H-CMC with 15 mL of 80% methanol, add 100 mL of 0.1N NaOH, and shake at room temperature for 3 hours. Excess NaOH is back titrated with 0.1N--H ₂ SO ₄ using phenolphthalein as an indicator, and the degree of carboxymethyl substitution (DS value) is calculated by the following formula.
A=[(100×F'-0.1N-H ₂ SO ₄ (mL)×F)×0.1]/(bone-dry mass of H-CMC (g))
Carboxymethyl substitution degree = 0.162 x A/(1-0.058 x A)
F': Factor of 0.1N-H ₂ SO ₄ F: Factor of 0.1N-NaOH.

The degree of carboxymethyl substitution in carboxymethylated cellulose nanofibers is usually the same as the degree of carboxymethyl substitution in carboxymethylated cellulose before it is made into nanofibers.

<Transparency in water dispersion>
The carboxymethylated cellulose nanofibers used in the present invention are characterized by exhibiting high transparency when made into a dispersion using water as a dispersion medium (aqueous dispersion). Nanofibers with high transparency are preferable because they can be used as additives for applications that require transparency. In this specification, transparency refers to the transmittance of light at a wavelength of 660 nm when carboxymethylated cellulose nanofibers are made into an aqueous dispersion with a solid content of 1% (w/v). The method for measuring the transparency of carboxymethylated cellulose nanofibers is as follows:
A cellulose nanofiber dispersion (solid content 1% (w/v), dispersion medium: water) was prepared, and a square cell with an optical path length of 10 mm was prepared using a UV-VIS spectrophotometer UV-1800 (manufactured by Shimadzu Corporation). The transmittance of 660 nm light is measured.

The transparency of the carboxymethylated cellulose nanofibers of the present invention is 70% or more. It is more preferably 70 to 100%, still more preferably 80 to 100%, even more preferably 90 to 100%. Such cellulose nanofibers can be optimally used in applications that require transparency. Carboxymethylated cellulose nanofibers having the above-mentioned cellulose type I crystallinity and carboxymethyl substitution degree and such transparency can be produced, for example, by the method described below.

<Fiber diameter, aspect ratio>
The carboxymethylated cellulose nanofibers used in the present invention have a nanoscale fiber diameter. The average fiber diameter is preferably 3 nm to 500 nm, more preferably 3 nm to 150 nm, even more preferably 3 nm to 20 nm, even more preferably 5 nm to 19 nm, even more preferably 5 nm to 15 nm.

The aspect ratio of the carboxymethylated cellulose nanofibers is not particularly limited, but is preferably 350 or less, more preferably 300 or less, even more preferably 200 or less, and even more preferably 120 or less. , more preferably 100 or less, and even more preferably 80 or less. When the aspect ratio is 350 or less, the fibers are not excessively long, the entanglement of the fibers is reduced, and the generation of lumps of cellulose nanofibers can be reduced, making it suitable for use as an additive. Suitable. Moreover, since it has high fluidity, it is easy to use even at high concentrations, and has the advantage of being easy to use even in applications requiring a high solid content. The lower limit of the aspect ratio is not particularly limited, but is preferably 25 or more, more preferably 30 or more. When the aspect ratio is 25 or more, the effect of improved thixotropy can be obtained due to the fibrous shape. The aspect ratio of carboxymethylated cellulose nanofibers can be controlled by the mixing ratio of solvent and water during carboxymethylation, the amount of chemicals added, and the degree of carboxymethylation, and can be produced, for example, by the manufacturing method described below. .

The average fiber diameter and average fiber length of carboxymethylated cellulose nanofibers were determined using an atomic force microscope (AFM) if the diameter was 20 nm or less, and a field emission scanning electron microscope (FE-SEM) if the diameter was 20 nm or more. It can be measured by analyzing 200 randomly selected fibers and calculating the average. Additionally, the aspect ratio can be calculated using the following formula:
Aspect ratio = average fiber length/average fiber diameter.

<Viscosity and thixotropy in water dispersion>
The carboxymethylated cellulose nanofibers used in the present invention are preferably those that exhibit high thixotropy when made into a dispersion (aqueous dispersion) using water as a dispersion medium. Thixotropy refers to the property that the viscosity gradually decreases when subjected to shear stress, and gradually increases when it stands still. In this specification, the viscosity measured at a low shear rate is used as an index of thixotropy. The value divided by the viscosity measured at high shear rate is used. Specifically, viscosity and thixotropy are measured by the following method:
A cellulose nanofiber dispersion (solid content 1% (w/v), dispersion medium: water) was prepared and left at 25°C for 16 hours, then stirred for 1 minute at 3000 rpm using a stirrer to prepare a sample for viscosity measurement. shall be. A part of the obtained sample for viscosity measurement was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.). Measure the viscosity after 3 minutes with 4 rotors/6 rpm. In addition, using another part of the sample for viscosity measurement (one whose viscosity has not yet been measured), No. Measure the viscosity after 3 minutes with 4 rotors/60 rpm. When measuring viscosity, follow the method of JIS-Z-8803. The value obtained by dividing the obtained viscosity at 6 rpm by the viscosity at 60 rpm is used as an index of thixotropy.

The carboxymethylated cellulose nanofibers used in the present invention have a viscosity at 25°C and 6 rpm when made into an aqueous dispersion with a solid content of 1% (w/v). It is preferable that the value divided by the viscosity at 25° C. and 60 rpm (also simply referred to as “the value obtained by dividing the viscosity at 6 rpm by the viscosity at 60 rpm”) is 6.0 or more. The higher this value is, the greater the change in viscosity due to the difference in shear stress is, and the higher the thixotropy. Cellulose nanofibers with high thixotropy are suitable for use as shape retention agents and viscosity modifiers. The upper limit of the value obtained by dividing the viscosity at 6 rpm by the viscosity at 60 rpm is not limited, but in reality, it is considered that about 15.0 is the upper limit.

The viscosity of the carboxymethylated cellulose nanofiber at 6 rpm (aqueous dispersion with a solid content of 1% (w/v), 25 ° C.) is preferably 15,000 mPa s or more, and more preferably 20,000 mPa s or more. . The higher the viscosity at low shear rate (6 rpm), the more thixotropic it can be. The upper limit of the viscosity at 6 rpm is not particularly limited, but realistically it is considered to be about 50,000 mPa·s.

The viscosity of the carboxymethylated cellulose nanofiber at 60 rpm (aqueous dispersion with a solid content of 1% (w/v), 25 ° C.) is preferably about 1500 to 8400 mPa s, and about 2000 to 7000 mPa s. More preferably, it is about 2,500 to 7,000 mPa·s, and even more preferably about 3,000 to 7,000 mPa·s.

Carboxymethylated cellulose nanofibers having such viscosity and thixotropy can be produced, for example, by the method described below.
<Others>
The carboxymethylated cellulose nanofibers used in the present invention may have a carboxyl group (-COOH) derived from a carboxymethyl group modified as appropriate within a range that does not impede the effects of the present invention. Such modification includes, for example, making carboxymethylated cellulose nanofibers hydrophobic by bonding an amine compound or phosphorus compound having an alkyl group, aryl group, aralkyl group, etc. to a carboxyl group.

Further, the carboxymethylated cellulose nanofibers used in the present invention may be metal-supported as long as the effects of the present invention are not impaired. Metal loading is carried out by bringing an aqueous solution containing a metal compound into contact with carboxymethylated cellulose nanofibers or carboxymethylated cellulose before fibrillation, so that carboxylate groups (-COO-) derived from carboxyl groups (-COOH) are supported. , refers to the formation of coordination bonds or hydrogen bonds between metal compounds. Thereby, carboxymethylated cellulose nanofibers containing a metal compound to which metal ions derived from the metal compound are ionically bonded can be obtained. Examples of such metal compounds include metal salts containing ions of one or more metal elements selected from the group of Ag, Au, Pt, Pd, Mn, Fe, Ti, Al, Zn, and Cu. can.

<Method for producing carboxymethylated cellulose nanofibers>
The crystallinity of cellulose I type is 60% or more, the degree of carboxymethyl substitution is 0.50 or less, and the transmittance of light at a wavelength of 660 nm when it is made into an aqueous dispersion with a solid content of 1% (w/v) is 7
Nanofibers of carboxymethylated cellulose having a content of 0% or more can be produced by defibrating carboxymethylated cellulose produced by the following method, although it is not limited thereto.

Carboxymethylated cellulose is generally produced by treating cellulose with an alkali (mercerization) and then reacting the obtained mercerized cellulose (also referred to as alkali cellulose) with a carboxymethylating agent (also referred to as an etherification agent). It can be manufactured by Carboxymethylated cellulose that can form nanofibers having the above characteristics of the present invention is produced by mercerization (alkali treatment of cellulose) in a solvent mainly composed of water, followed by carboxymethylation (also called etherification). ) in a mixed solvent of water and an organic solvent. The carboxymethylated cellulose obtained in this way can be produced using conventional water-based methods (both mercerization and carboxymethylation are performed using water as a solvent) or solvent methods (both mercerization and carboxymethylation are performed using an organic solvent). Compared to carboxymethylated cellulose obtained by the main method (method carried out in a solvent), it has a higher effective utilization rate of carboxymethylating agent, and when defibrated, it becomes a highly transparent cellulose nanofiber dispersion. can be converted.

<Cellulose>
In the present invention, cellulose refers to a polysaccharide having a structure in which D-glucopyranose (simply referred to as "glucose residue" or "anhydroglucose") is linked through β-1,4 bonds. Cellulose is generally classified into natural cellulose, regenerated cellulose, fine cellulose, microcrystalline cellulose excluding non-crystalline regions, etc. based on its origin, manufacturing method, etc. In the present invention, any of these celluloses can be used as a raw material for mercerized cellulose, but in order to maintain cellulose I type crystallinity of 60% or more in carboxymethylated cellulose nanofibers, cellulose I It is preferable to use cellulose having a high degree of crystallinity as a raw material. The crystallinity of cellulose type I cellulose used as a raw material is preferably 70% or more, more preferably 80% or more. The method for measuring the crystallinity of cellulose type I is as described above.

Examples of natural cellulose include bleached pulp or unbleached pulp (bleached wood pulp or unbleached wood pulp); linters, purified linters; and cellulose produced by microorganisms such as acetic acid bacteria. The raw material for bleached pulp or unbleached pulp is not particularly limited, and examples thereof include wood, cotton, straw, bamboo, hemp, jute, kenaf, and the like. Furthermore, the method for producing bleached pulp or unbleached pulp is not particularly limited, and may be a mechanical method, a chemical method, or a combination of the two in between. Examples of bleached pulp or unbleached pulp classified by manufacturing method include mechanical pulp (thermomechanical pulp (TMP), groundwood pulp), chemical pulp (softwood unbleached sulfite pulp (NUSP), softwood bleached sulfite pulp (NBSP) ), kraft pulp such as softwood unbleached kraft pulp (NUKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), etc. Furthermore, dissolving pulp may be used in addition to papermaking pulp. Dissolving pulp is a chemically refined pulp that is mainly used after being dissolved in chemicals, and is the main raw material for artificial fibers, cellophane, etc.

Examples of regenerated cellulose include those obtained by dissolving cellulose in some kind of solvent such as a cupric ammonia solution, a cellulose xanthate solution, or a morpholine derivative, and respinning the resulting solution.
Fine cellulose is obtained by depolymerizing cellulose materials such as the above-mentioned natural cellulose and regenerated cellulose (for example, acid hydrolysis, alkaline hydrolysis, enzymatic decomposition, blasting treatment, vibrating ball mill treatment, etc.) Examples include those obtained by mechanically processing the above-mentioned cellulose-based materials.

<Mercerization>
Mercerized cellulose (also referred to as alkali cellulose) is obtained by using the aforementioned cellulose as a raw material and adding a mercerizing agent (alkali). According to the method described in this specification, water is mainly used as a solvent in this mercerization reaction, and a mixed solvent of an organic solvent and water is used in the subsequent carboxymethylation. It is possible to economically obtain carboxymethylated cellulose, which can be made into a cellulose nanofiber dispersion with high transparency.

The expression "mainly using water as a solvent (solvent mainly consisting of water)" refers to a solvent containing water in a proportion higher than 50% by mass. The water content in the water-based solvent is preferably 55% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass or more, More preferably, it is 90% by mass or more, and even more preferably 95% by mass or more. Particularly preferably, the water-based solvent is 100% by weight water (ie, water). The higher the proportion of water during mercerization, the higher the transparency of the cellulose nanofiber dispersion obtained by defibrating carboxymethylated cellulose. Examples of solvents other than water in the water-based solvent (used in combination with water) include organic solvents used as solvents in the subsequent carboxymethylation. For example, alcohols such as methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, and tertiary butanol; ketones such as acetone, diethyl ketone, and methyl ethyl ketone; and dioxane, diethyl ether, benzene, and dichloromethane. They can be used alone or in a mixture of two or more of them as a solvent during mercerization by adding them to water in an amount of less than 50% by mass. The organic solvent in the water-based solvent is preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, even more preferably 20% by mass or less. , more preferably 10% by mass or less, still more preferably 5% by mass or less, and even more preferably 0% by mass.

Examples of the mercerizing agent include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and any one or a combination of two or more of these can be used. Mercerizing agents include, but are not limited to, adding these alkali metal hydroxides to a reactor as an aqueous solution of, for example, 1 to 60% by weight, preferably 2 to 45% by weight, more preferably 3 to 25% by weight. Can be added.

The amount of the mercerizing agent used is an amount that can maintain the crystallinity of cellulose I type in carboxymethylated cellulose at 60% or more, and in one embodiment, it is 0.1 mol or more per 100 g of cellulose (bone dry). The amount is preferably .5 mol or less, more preferably 0.3 mol or more and 2.0 mol or less, and even more preferably 0.4 mol or more and 1.5 mol or less.

The amount of the solvent mainly composed of water during mercerization is preferably 1.5 to 20 times by mass, more preferably 2 to 10 times by mass, based on the cellulose raw material. With such an amount, it becomes easy to stir and mix the raw materials, and it becomes possible to cause the raw materials to react uniformly.

In the mercerization treatment, the bottom raw material (cellulose) and a solvent mainly composed of water are mixed, and the temperature of the reactor is adjusted to 0 to 70°C, preferably 10 to 60°C, more preferably 10 to 40°C. Then, an aqueous solution of a mercerizing agent is added thereto, followed by stirring for 15 minutes to 8 hours, preferably 30 minutes to 7 hours, more preferably 30 minutes to 3 hours. This yields mercerized cellulose (alkali cellulose).

The pH during mercerization is preferably 9 or higher, so that the mercerization reaction can proceed. The pH is more preferably 11 or more, still more preferably 12 or more, and may be 13 or more. The upper limit of pH is not particularly limited.

Mercerization can be carried out using a reactor capable of mixing and stirring the above components while controlling the temperature, and various reactors conventionally used for mercerization reactions can be used. For example, a batch type stirring device in which two shafts stir and mix the above-mentioned components is preferable from the viewpoints of both uniform mixing performance and productivity.

<Carboxymethylation>
Carboxymethylated cellulose is obtained by adding a carboxymethylating agent (also referred to as an etherifying agent) to mercerized cellulose. According to the method described in this specification, water is used as the main solvent during mercerization, and a mixed solvent of water and organic solvent is used during carboxymethylation. It is possible to economically obtain carboxymethylated cellulose, which can be made into a cellulose nanofiber dispersion with high transparency.

Examples of the carboxymethylating agent include monochloroacetic acid, sodium monochloroacetate, methyl monochloroacetate, ethyl monochloroacetate, isopropyl monochloroacetate, and the like. Among these, monochloroacetic acid or sodium monochloroacetate is preferred from the viewpoint of easy availability of raw materials.

The amount of the carboxymethylating agent used is an amount that can maintain the crystallinity of cellulose I type at 60% or more, and also an amount that provides a degree of carboxymethyl substitution of 0.50 or less. Although not particularly limited, in one embodiment, it is preferably added in an amount of 0.5 to 1.5 mol per anhydroglucose unit of cellulose. The lower limit of the above range is more preferably 0.6 mol or more, even more preferably 0.7 mol or more, and the upper limit is more preferably 1.3 mol or less, still more preferably 1.1 mol or less. The carboxymethylating agent can be added to the reactor as an aqueous solution of, for example, 5 to 80% by mass, more preferably 30 to 60% by mass, but is not limited thereto, or it can be added in the form of a powder without being dissolved. You can also do that.

The molar ratio of the mercerizing agent and the carboxymethylating agent (mercerizing agent/carboxymethylating agent) is generally 0.9 to 2.45 when monochloroacetic acid or sodium monochloroacetate is used as the carboxymethylating agent. will be adopted. The reason is that if it is less than 0.9, the carboxymethylation reaction may be insufficient, and unreacted monochloroacetic acid or sodium monochloroacetate may remain and be wasted. If it exceeds 100%, a side reaction between the excess mercerizing agent and monochloroacetic acid or sodium monochloroacetate may proceed to produce an alkali metal salt of glycolate, which may be uneconomical.

In carboxymethylation, the effective utilization rate of the carboxymethylating agent is preferably 15% or more. It is more preferably 20% or more, still more preferably 25% or more, particularly preferably 30% or more. The effective utilization rate of a carboxymethylating agent refers to the proportion of carboxymethyl groups introduced into cellulose among the carboxymethyl groups in the carboxymethylating agent. By using a solvent mainly composed of water during mercerization and using a mixed solvent of water and an organic solvent during carboxymethylation, a high effective utilization rate of the carboxymethylating agent (i.e., It is possible to produce carboxymethylated cellulose that can yield a cellulose nanofiber dispersion with high transparency when defibrated (economically, without significantly increasing the amount of carboxymethylated cellulose used). Although the upper limit of the effective utilization rate of the carboxymethylating agent is not particularly limited, the practical upper limit is about 80%. Note that the effective utilization rate of the carboxymethylating agent is sometimes abbreviated as AM.

The method for calculating the effective utilization rate of carboxymethylating agents is as follows:
AM = (DS × number of moles of cellulose) / number of moles of carboxymethylating agent DS: degree of carboxymethyl substitution (measurement method is as described above)
Number of moles of cellulose: Pulp mass (dry mass when dried at 100° C. for 60 minutes)/162 (162 is the molecular weight per glucose unit of cellulose).

The concentration of the cellulose raw material in the carboxymethylation reaction is not particularly limited, but from the viewpoint of increasing the effective utilization rate of the carboxymethylation agent, it is preferably 1 to 40% (w/v).

Simultaneously with the addition of the carboxymethylating agent, or before or immediately after the addition of the carboxymethylating agent, add an organic solvent or an aqueous solution of an organic solvent to the reactor, or remove water other than water during the mercerization treatment by reducing pressure, etc. The organic solvent and the like are appropriately reduced to form a mixed solvent of water and an organic solvent, and the carboxymethylation reaction is allowed to proceed in this mixed solvent of water and an organic solvent. The timing of adding or reducing the organic solvent may be from the end of the mercerization reaction to immediately after adding the carboxymethylating agent, and is not particularly limited, but for example, 30 minutes before or after adding the carboxymethylating agent. Preferably within

Examples of organic solvents include alcohols such as methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, and tertiary butanol, ketones such as acetone, diethyl ketone, and methyl ethyl ketone, as well as dioxane, diethyl ether, Benzene, dichloromethane, etc. can be mentioned, and these alone or a mixture of two or more can be added to water and used as a solvent during carboxymethylation. Among these, monohydric alcohols having 1 to 4 carbon atoms are preferred, and monohydric alcohols having 1 to 3 carbon atoms are more preferred because of their excellent compatibility with water.

The proportion of the organic solvent in the mixed solvent during carboxymethylation is preferably 20% by mass or more, more preferably 30% by mass or more, based on the total of water and organic solvent. It is more preferably 40% by mass or more, even more preferably 45% by mass or more, and particularly preferably 50% by mass or more. The higher the proportion of the organic solvent, the higher the transparency of the cellulose nanofiber dispersion. The upper limit of the proportion of the organic solvent is not limited, and may be, for example, 99% by mass or less. Considering the cost of the organic solvent to be added, it is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, and still more preferably 70% by mass or less.

The reaction medium for carboxymethylation (a mixed solvent of water and organic solvent, etc. that does not contain cellulose) has a lower proportion of water than the reaction medium for mercerization (in other words, the proportion of organic solvent is lower) than the reaction medium for mercerization. Preferably. By satisfying this range, it becomes easier to increase the degree of carboxymethyl substitution while maintaining the crystallinity of the carboxymethylated cellulose obtained, and when defibrated, the carboxymethylated cellulose becomes a highly transparent cellulose nanofiber dispersion. can be obtained more efficiently. In addition, if the reaction medium for carboxymethylation has a lower proportion of water (larger proportion of organic solvent) than the reaction medium for mercerization, when transitioning from the mercerization reaction to the carboxymethylation reaction, Another advantage is that a mixed solvent for the carboxymethylation reaction can be formed by simply adding a desired amount of organic solvent to the reaction system after the mercerization reaction is completed.

After forming a mixed solvent of water and an organic solvent and adding the carboxymethylating agent to the mercerized cellulose, the temperature is preferably kept constant in the range of 10 to 40°C for 15 minutes to 4 hours, preferably for 15 minutes. Stir for about 1 minute to 1 hour. The liquid containing mercerized cellulose and the carboxymethylating agent are preferably mixed in multiple batches or by dropwise addition in order to prevent the reaction mixture from reaching a high temperature. After adding the carboxymethylating agent and stirring for a certain period of time, raise the temperature if necessary to bring the reaction temperature to 30 to 90°C, preferably 40 to 90°C, more preferably 60 to 80°C, for 30 minutes to The etherification (carboxymethylation) reaction is carried out for 10 hours, preferably 1 to 4 hours, to obtain carboxymethylated cellulose.

For carboxymethylation, the reactor used for mercerization may be used as is, or a separate reactor may be used that can mix and stir the above components while controlling the temperature. .

After the reaction is complete, the remaining alkali metal salt may be neutralized with a mineral or organic acid. Further, if necessary, by-produced inorganic salts, organic acid salts, etc. may be removed by washing with water-containing methanol, followed by drying, pulverization, and classification to obtain carboxymethylated cellulose or its salt. When washing to remove by-products, it may be made into an acid form in advance and linearized, and then returned to a salt form after washing. Examples of devices used for dry grinding include impact mills such as hammer mills and pin mills, media mills such as ball mills and tower mills, and jet mills. Examples of devices used in wet grinding include homogenizers, mass colloiders, pearl mills, and the like.

<Defibration into nanofibers>
By defibrating the carboxymethylated cellulose obtained by the above method, it can be converted into cellulose nanofibers having a nanoscale fiber diameter.

At the time of defibration, a dispersion of carboxymethylated cellulose obtained by the above method is prepared. The dispersion medium is preferably water from the viewpoint of ease of handling. The concentration of carboxymethylated cellulose in the dispersion during defibration is preferably 0.01 to 10% (w/v) in consideration of the efficiency of defibration and dispersion.

The device used to defibrate carboxymethylated cellulose is not particularly limited, but a high-speed rotation type, a colloid mill type, a high pressure type, a roll mill type, an ultrasonic type, or the like can be used. During defibration, it is preferable to apply a strong shearing force to the dispersion of carboxymethylated cellulose. Particularly, in order to efficiently defibrate, it is preferable to use a wet high-pressure or ultra-high-pressure homogenizer that can apply a pressure of 50 MPa or more to the dispersion and a strong shearing force. The pressure is more preferably 100 MPa or more, and still more preferably 140 MPa or more. Furthermore, prior to the defibration and dispersion treatment with a high-pressure homogenizer, the dispersion may be pretreated, if necessary, using a known mixing, stirring, emulsifying, and dispersing device such as a high-speed shear mixer. .

A high-pressure homogenizer uses a pump to pressurize the fluid (high pressure) and eject it from very delicate gaps in the flow path, emulsifying and dispersing it using the combined energy of collisions between particles and shearing force due to pressure differences. This is a device that performs pulverization, pulverization, and ultra-fine refining.

Although it is not clear why cellulose nanofibers with high transparency can be obtained by the above method, it is possible to maintain a relatively high crystallinity of cellulose type I according to the above method, and therefore the degree of carboxymethyl substitution is The present inventors have confirmed that it is possible to maintain the fibrous shape of carboxymethylated cellulose even if the ratio is relatively high. It is thought that increasing the degree of carboxymethyl substitution (in other words, introducing a large number of carboxymethyl groups) while maintaining the fibrous shape leads to improved fibrillation properties of carboxymethylated cellulose, which leads to highly transparent nano It is assumed that this is one of the reasons why a fiber dispersion can be obtained. However, it is not limited to this.

<Additives>
The carboxymethylated cellulose nanofibers obtained by the above production method, which have a degree of carboxymethyl substitution of 0.50 or less, a cellulose I type crystallinity of 60% or more, and a transparency of 60% or more, are homogeneous. It has excellent dispersion stability, excellent water retention and shape retention, and is relatively non-sticky and smooth when it comes into contact with water, does not easily form lumps in water, and has highly transparent water. Because it can provide a dispersion, it is used as a water retention agent, shape retention agent, viscosity modifier, emulsion stabilizer, dispersion stabilizer, etc. in various fields such as food, medicine, cosmetics, feed, paper manufacturing, and paints. It can be suitably used as various additives.

In addition, it has excellent miscibility with other materials, exhibits thixotropic properties when dispersed in water or a hydrophilic organic solvent, and becomes gel-like under certain conditions, making it effective as a gelling agent. Furthermore, by forming a film using a papermaking method or a casting method, a material with high strength, excellent heat resistance, and low thermal expansion can be obtained. The membrane thus obtained is also useful as a coating layer for the purpose of imparting hydrophilic properties. Furthermore, when composited with other materials such as resins, it has excellent dispersibility in the other materials, so if suitable, a composite with excellent transparency can be provided. It also functions as a reinforcing filler, and when the fibers form a highly networked structure in the composite, it exhibits higher strength than the resin used alone and can also lower the coefficient of thermal expansion. can. In addition, since it has amphipathic properties, it functions as an emulsifier and a dispersion stabilizer. Furthermore, since the carboxymethyl group forms counter ions with metal ions, it is effective as a metal ion scavenger.

The fields in which carboxymethylated cellulose nanofibers are used are not limited, and include various fields in which additives are generally used, such as cosmetics, foods, beverages, medicines, paper manufacturing, various chemical supplies, paints, inks, sprays, and feeds. , agricultural chemicals, glazes, civil engineering, architecture, electronic materials, flame retardants, household goods, adhesives, cleaning agents, fragrances, lubricating compositions, etc.; thickeners, gelling agents, glues, food additives, and fillers. Excipients, additives for paints, additives for adhesives, additives for paper manufacturing, abrasives, compounded materials for rubber and plastics, water retention agents, shape retention agents, viscosity modifiers, emulsion stabilizers, bubble stabilizers It can be used as a dispersion stabilizer, muddy water conditioner, filter aid, mud flooding prevention agent, etc.

For example, the additive containing carboxymethylated cellulose nanofibers of the present invention can be used for manganese dry batteries, alkaline manganese batteries, silver oxide batteries, lithium batteries, lead acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, Silver-zinc oxide batteries, lithium-ion batteries, lithium-polymer batteries, various gel electrolyte batteries, all-solid-state batteries, zinc-air batteries, iron-air batteries, aluminum-air batteries, fuel cells, solar cells, sodium-sulfur batteries, polyacene It can be used as an additive to various battery components such as batteries, electrolytic capacitors, and electric double layer capacitors (also referred to as electric double layer capacitors). Examples include active materials, insulating films (separators), and electrolyte films. It is also effective as a binder between the current collector of each electrode and the active material, a binder between active materials, a dispersant for active materials, a dispersant for solid electrolytes, and the like.

When the additive containing the carboxymethylated cellulose nanofiber of the present invention is used as a cosmetic additive, examples include, but are not limited to, a water retention agent, a shape retention agent, a viscosity modifier, an emulsion stabilizer, and an emulsion stabilizer for cosmetics. It can be used as an agent, feel improver, foam stabilizer, and dispersion stabilizer. Examples of cosmetics include lotions, serums, emulsions, moisture creams, all-in-one gels, perfumes, facial cleansing foams, foams, cleansers, packs, sunscreens, massage products, whitening cosmetics, anti-aging products, beauty masks, etc. skin care products; makeup products such as foundation, lipstick, eyebrow, mascara, eyeliner, eye shadow, nail polish, nail care, powder, lip balm, lip gloss, lip liner, blush, BB cream, concealer; shampoo, hair color, Treatments, hair sprays, liquid hair styling products, hair creams, hair waxes, hair gels, setting lotions, scalp care cosmetics, eyelash care cosmetics, eyebrow care cosmetics, perming agents, hair dye solutions, hair dye creams, hair growth agents Hair care products such as; body care products such as body cream, hand cream, body shampoo, soap, shaving cream, shaving lotion, etc. Further, the product is not limited to oil, liquid, wax, stick, powder, or sheet-like products, and may be used in an aerosol type with a propellant such as liquefied petroleum gas.

For example, by adding the additive of the present invention to powdered makeup products such as foundations, eyebrows, and mascaras, they can be applied with shape retention or thixotropic properties that improve pigment dispersibility and prevent clumps. Effects such as improved ease of use, fixability, and gloss can be obtained.

For example, by blending the additive of the present invention into cream, liquid, or gel cosmetics such as BB cream, moisture cream, hair cream, liquid hair conditioner, hair gel, and hair wax, powder raw materials such as pigments can be used. Improved dispersibility of liquid ingredients, improved emulsification of liquid raw materials, ease of application by imparting thixotropic properties, improved and sustained hair styling properties by imparting shape retention and thixotropic properties, and improvement of suppleness and shine. Effects can be obtained.

For example, by incorporating the additive of the present invention into cosmetics that are used in the form of foam, such as shampoos, soaps, body shampoos, facial cleansers, and foams, it is possible to improve the stability of the foam by imparting shape retention, and to improve the foam. Effects such as improved and sustained skin smoothness and moisturized feeling after rinsing can be obtained.

Furthermore, by incorporating the additive of the present invention into cosmetics such as lotions and serums that are expected to impart moisturizing properties to the skin, a high moisturizing effect can be obtained by imparting water-holding properties with carboxymethylated cellulose nanofibers. be able to.

Furthermore, for example, when the additive of the present invention is used in a mist type lotion, etc., it is possible to obtain the effect of making it easier to spray by imparting thixotropic properties.
Furthermore, for example, when the additive of the present invention is used in a beauty pack, it is possible to obtain the effect that it is difficult to drip after being applied to the skin and is easy to use due to the imparting of thixotropic properties and shape-retaining properties.

When used as food additives, food additives include, but are not limited to, water retention agents, shape retention agents, viscosity modifiers, emulsion stabilizers, texture improvers, foam stabilizers, and dispersion stabilizers. Can be mentioned. Foods that can be used include, but are not limited to, beverages (cocoa, juices with fiber and pulp, shiruko, amazake, lactic acid bacteria drinks, fruit milk, soft drinks, carbonated drinks, alcoholic drinks, etc.), soups (corn soup, ramen noodles, etc.) soup, miso soup, consommé, etc.), sauces, dressings, ketchup, mayonnaise, jam, yogurt, whipped cream, dried goods (dried processed foods, instant ramen, pasta noodles, etc.), gluten-free pasta, ice cream, monaka, sorbet, Polyjuice, confectionery (gummy, soft candy, jelly, cookies, etc.), swallowable foods (gel-like foods such as thickening agents, medication aid jelly, etc.), wafer, agar, tokoroten, pullulan, starch syrup, meringue, bread (melon bread, cream) (bread, etc.), gluten-free bread, fillings, pancakes, pastes, frozen foods, processed meat foods, processed fish foods, processed rice products (rice cakes, rice crackers, arare), and edible films.

When used as an additive for pharmaceuticals or quasi-drugs, examples include, but are not limited to, water retention agents, shape retention agents, viscosity modifiers, emulsion stabilizers, and dispersion stabilizers for pharmaceuticals. Pharmaceuticals and quasi-drugs include, but are not limited to, tablets, ointments, bandages, poultices, hand creams, toothpastes, medicinal cosmetics, hair preparations, medicated toothpastes, bath additives, insecticides, rat poisons, and armpit odor. Examples include antiseptic agents, disinfectants for soft contact lenses, mouth fresheners, hair restorers, hair removers, hair dyes, bleaching/destaining agents, and permanent waving agents.

When used as a feed additive, examples include, but are not limited to, water retention agents, shape retention agents, viscosity modifiers, emulsion stabilizers, and dispersion stabilizers for feed. Examples of the feed include moist pellets for livestock and farmed fish, expansion pellets, and milk replacer for cows.

When used as an additive for paper manufacturing, examples include, but are not limited to, water retention agents, shape retention agents, viscosity modifiers, emulsion stabilizers, and dispersion stabilizers for paper manufacturing. For example, it can be used as a surface sizing agent, a retention improver, a paper strength enhancer, a coating agent, a barrier property imparting agent, an additive for bulky paper, and the like.

When used as a paint additive, examples include, but are not limited to, water retention agents, shape retention agents, viscosity modifiers, emulsion stabilizers, and dispersion stabilizers for paints. Examples of the paint include clear paint, matte paint, architectural paint, lacquer paint, craft paint, and automobile interior paint.

Other dispersion stabilizers and reinforcing materials for everyday items such as detergents, fabric softeners, wraps, films, wet tissues, and bath salts; filtration (moisture removal) of cooking oil and various solvents; fiber walls, wall materials, roofing materials, and concrete. Reinforcing materials for building materials such as , mortar, ceramics, ceramics, sand walls, and gypsum boards; Civil engineering such as bubble shields and wall sealants; Resin fillers and compounds such as styrofoam, biodegradable resins, rubber, ceramics, and PVC; Or reinforcing material; dispersing agent such as fine particle carbon black, barium sulfate (X-ray contrast agent), dispersion of titanium oxide or zinc oxide; moisture absorbing agent auxiliary agent such as improving the shape retention of deliquescent agents such as calcium chloride when absorbing moisture. Modifier for fibers (fabric, thread); Liquid carrier; Lubricating oil agent; Ceramics; Cat litter; Water-absorbing material for desiccant; Greening method; Binder; Pet supplies; Sanitary products; Wallpaper; Can also be used in culture media, etc. .

In addition, when using carboxymethylated cellulose nanofibers as additives for various purposes, they may be used as pH regulators, preservatives, rust preventives, surfactants, binders, adhesives, etc., within the range that does not impede the effects of the present invention. agents, foaming agents, excipients, coupling agents, adhesives, dispersants, adhesives, lubricants, mold release agents, viscosity modifiers, emulsion stabilizers, lubricants, abrasives, colorants, etc. It may be mixed into the carboxymethylated cellulose nanofiber additive.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, unless otherwise specified, parts and % indicate parts by mass and % by mass.

(Manufacturing example 1)
130 parts of water and a solution of 20 parts of sodium hydroxide dissolved in 100 parts of water were added to a twin-screw kneader whose rotational speed was adjusted to 150 rpm, and hardwood pulp (manufactured by Nippon Paper Industries, Ltd., LBKP) was heated at 100°C and 60°C. The dry weight after drying for minutes was 100 parts. The mixture was stirred and mixed at 35° C. for 80 minutes to prepare mercerized cellulose. Further, while stirring, 230 parts of isopropanol (IPA) and 60 parts of sodium monochloroacetate were added, and after stirring for 30 minutes, the temperature was raised to 70° C. and a carboxymethylation reaction was carried out for 90 minutes. The concentration of IPA in the reaction medium during the carboxymethylation reaction is 50%. After the reaction was completed, the mixture was neutralized with acetic acid until the pH reached 7, washed with aqueous methanol, deliquified, dried, and pulverized to obtain the sodium salt of carboxymethylated cellulose.

The obtained sodium salt of carboxymethylated cellulose was dispersed in water to form an aqueous dispersion with a solid content of 1% (w/v). This was treated three times with a 140 MPa high-pressure homogenizer to obtain a dispersion of carboxymethylated cellulose nanofibers. The transparency and viscosity of the obtained dispersion, the average fiber diameter of cellulose nanofibers, the degree of carboxymethyl substitution, the degree of crystallinity of cellulose type I, and the effective utilization rate of the carboxymethylating agent were measured by the methods described above. .

(Manufacturing example 2)
A sodium salt of carboxymethylated cellulose was obtained in the same manner as in Production Example 1, except that the concentration of IPA in the reaction solution during the carboxymethylation reaction was adjusted to 90% by changing the amount of IPA added. The degree of carboxymethyl substitution was 0.47, the crystallinity of type I cellulose was 63%, and the effective utilization rate of the carboxymethylating agent was 56%. The obtained sodium salt of carboxymethylated cellulose was defibrated in the same manner as in Production Example 1 to obtain a dispersion of carboxymethylated cellulose nanofibers.

(Manufacturing example 3)
A sodium salt of carboxymethylated cellulose was obtained in the same manner as in Production Example 1, except that the concentration of IPA in the reaction solution during the carboxymethylation reaction was changed to 30% by changing the amount of IPA added. The obtained sodium salt of carboxymethylated cellulose was defibrated in the same manner as in Production Example 1 to obtain a dispersion of carboxymethylated cellulose nanofibers.

(Manufacturing example 4)
During the mercerization reaction, 40 parts of sodium hydroxide dissolved in 100 parts of water was used instead of 20 parts of sodium hydroxide dissolved in 100 parts of water, and sodium monochloroacetate was used as the carboxymethylating agent during the carboxymethylation reaction. A sodium salt of carboxymethylated cellulose was obtained in the same manner as in Production Example 1 except that 50 parts of monochloroacetic acid was used instead of 60 parts. The degree of carboxymethyl substitution was 0.31, the crystallinity of type I cellulose was 60%, and the effective utilization rate of the carboxymethylating agent was 36%. The obtained sodium salt of carboxymethylated cellulose was defibrated in the same manner as in Production Example 1 to obtain a dispersion of carboxymethylated cellulose nanofibers.

(Comparative production example 5)
The solvent for the carboxymethylation reaction was 100% water, and for the mercerization reaction, 45 parts of sodium hydroxide dissolved in 100 parts of water was used instead of 20 parts of sodium hydroxide dissolved in 100 parts of water. A sodium salt of carboxymethylated cellulose was obtained in the same manner as in Production Example 1, except that 150 parts of sodium monochloroacetate was used in place of 60 parts of sodium monochloroacetate as the carboxymethylating agent during the methylation reaction. The degree of carboxymethyl substitution was 0.28, the crystallinity of type I cellulose was 45%, and the effective utilization rate of the carboxymethylating agent was 13%. The obtained sodium salt of carboxymethylated cellulose was defibrated in the same manner as in Production Example 1 to obtain a dispersion of carboxymethylated cellulose nanofibers.

(Comparative production example 6)
A sodium salt of carboxymethylated cellulose was obtained in the same manner as in Production Example 1, except that the solvent during the mercerization reaction was 10% water and 90% IPA, and a solvent with the same composition was used during the carboxymethylation reaction. The obtained sodium salt of carboxymethylated cellulose was defibrated in the same manner as in Production Example 1 to obtain a dispersion of carboxymethylated cellulose nanofibers.

(Example 1: Facial cleanser)
Using each of the cellulose nanofiber sodium salts of Production Examples 1 to 4 and Comparative Production Examples 5 and 6, facial cleansers were produced using the following formulations and a commonly used method.

Facial cleanser formulation Sodium N-acylglutamate 20.0% by mass
Glycerin 10.0% by mass
PEG 15.0% by mass
DPG 10.0% by mass
Acylmethyltaurine 5.0% by mass
POE/POP block polymer 5.0% by mass
POE (15) Oleyl alcohol ether 3.0% by mass
Lanolin derivative 2.0% by mass
Acrylic acid/acrylic acid/dimethyldiallylammonium chloride copolymer liquid 3.0% by mass
Each cellulose nanofiber 10.0% by mass
Purified water: 100.0% by mass Preservative: Appropriate amount Chelating agent: Appropriate amount Flavor: Appropriate amount Color: Appropriate amount.

The facial cleansers obtained using the cellulose nanofibers of Production Examples 1 to 4 had a smooth and homogeneous texture before lathering, were not sticky, and foamed well, and the foam after lathering was firm and hard to disappear. . When I used it, it not only gave me a refreshing cleansing experience, but also left my skin feeling moisturized. The facial cleanser using cellulose nanofibers of Comparative Production Example 5 had a slightly sticky feel and the foam tended to disappear easily. The facial cleanser using cellulose nanofibers of Comparative Production Example 6 still had a sticky feel, and the foam tended to disappear more easily.

(Example 2: Hair wax)
Production Examples 1 to 4 and Comparative Example Using each of the cellulose nanofiber sodium salts of Production Examples 5 and 6, hair wax was produced according to a commonly used method using the formulation shown below.

Hair wax formulation Castor oil 2.0% by mass
Candelilla wax 3.0% by mass
White beeswax 20.0% by mass
Polyoxyethylene hydrogenated castor oil 12.0% by mass
O-(2-hydroxy-3-trimethylammoniopropyl)hydroxyethylcellulose chloride 3.0% by mass
Highly polymerized methylpolysiloxane 2.0% by mass
Methylsiloxane 3.0% by mass
Alkyl modified silicone 5.0% by mass
Each cellulose nanofiber 5.0% by mass
Bentonite 8.0% by mass
Talc 1.0% by mass
Cetyl hydroxycellulose 2.0% by mass
Purified water 100.0% by mass Preservative 1.0% by mass
Chelating agent Appropriate amount.

The hair wax obtained using the cellulose nanofibers of Production Examples 1 to 4 had a smooth and homogeneous texture, was not sticky when applied to the hands, quickly softened, and was easy to use. Furthermore, when applied to the hair, it had high styling properties (hairstyle retention), but the hair did not become too stiff, and the hair felt supple and moisturized. The hair wax using cellulose nanofibers of Comparative Production Example 5 had a slightly sticky feel and tended to have a slightly weak hairstyle retention property. The hair wax using cellulose nanofibers of Comparative Production Example 6 also had a sticky feel and tended to have weaker hairstyle retention.
(Example 3: Lotion)
Using each of the cellulose nanofiber sodium salts of Production Examples 1 to 4 and Comparative Production Examples 5 and 6, lotions were produced using the following formulations and a commonly used method.

Lotion formulation POE sorbitan monostearate 40.0% by mass
Ethanol 26.0% by mass
1,3-butylene glycol 5.0% by mass
Zinc sulfocarbonate 5.0% by mass
Ceramide 5.0% by mass
Collagen 3.0% by mass
Lecithin 3.0% by mass
Sodium hyaluronate 3.0% by mass
Vitamin 3.0% by mass
Placenta extract 2.0% by mass
Glycerin Appropriate amount Pigment Appropriate amount Flavoring Appropriate amount Plant extract liquid Appropriate amount Quince seed Appropriate amount Purified water Amount to make 100.0% by mass Each cellulose nanofiber 2.0% by mass.

The lotions obtained using the cellulose nanofibers of Production Examples 1 to 4 were homogeneous. When applied to the skin, there was no unpleasant stickiness, but a good feeling of moisture was felt. The lotions using cellulose nanofibers in Comparative Production Examples 5 and 6 had a slightly sticky feel.

(Example 4: Various formulation examples)
Some formulation examples of products using additives containing cellulose nanofaber of the present invention are shown below. All numerical units in the formulation examples are mass %. The additive of the present invention can be suitably used as various additives in various fields in addition to those shown below.

Shampoo Polyoxyethylene Lauryl Ether Sodium Sulfate 5.0
Polyoxyethylene lauryl ether sulfate triethanolamine 3.0
Coconut oil fatty acid sarcosine sodium 2.0
Coconut oil fatty acid amidopropyl betaine 2.0
2-Alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine 2.0% by mass
Polyoxyethylene lauryl ether 1.0
Ethylene glycol distearate 3.0
Coconut oil fatty acid diethanolamide 1.0
Polyoxyethylene/methylpolysiloxane copolymer 1.0
Methyl polysiloxane 0.5
Polyglyceryl diisostearate 2.0
Mixed plant extract (10) 0.5
Hydrolyzed keratin powder 0.3
Sodium ascorbate 0.1
Piroctone Olamine 0.5
Methylparaben 0.3
Dimethyldiallylammonium chloride/acrylamide copolymer 0.1
O-(2-hydroxy-3-trimethylammoniopropyl)hydroxyethylcellulose chloride 0.1
Cellulose nanofiber 0.01～30.0
Amount to make 100 purified water.

Rinse Cetostearyl Alcohol 3.0
oleyl alcohol 2.0
White petrolatum 0.5
N-alkylene monoisostearate (20-30) glycol 1.0
Liquid paraffin 1.0
Octyl palmitate 2.0
Rice bran oil 1.0
2-ethylhexyl paramethoxycinnamate 0.2
Alkyltrimethylammonium chloride 3.0
Lipophilic glyceryl monostearate 1.0
Ethyl sulfate lanolin fatty acid aminopropylethyldimethylammonium (2) 2.0
Phenoxyethanol 0.2
Seaweed extract (1) 0.1
Hydroxyethylcellulose 0.5
O-(2-hydroxy-3-trimethylammoniopropyl)hydroxyethylcellulose chloride 0.1
1,3-butylene glycol 2.0
Concentrated glycerin 2.0
Ethanol 5.0
Cellulose nanofiber 0.01～30.0
Amount to make 100 purified water.

Body shampoo lauric acid 5.0
Myristic acid 10.0
N-coconut oil fatty acyl-L-sodium glutamate 3.0
Sodium β-lauroylaminopropionate 3.0
Coconut oil fatty acid amidopropyl betaine 2.0
Lauric acid diethanolamide 2.0
Polyoxyethylene hydrogenated castor oil 2.0
Polyethylene glycol monostearate 3.0
Lanolin fatty acid polyethylene glycol 1000 1.0
Propylene glycol 5.0
Dibutylhydroxytoluene 0.2
Potassium hydroxide 3.0
Triethanolamine 0.3
Methylparaben 0.3
Phytic acid 0.3
Calcium disodium ethylenediaminetetraacetate 0.2
Water-soluble collagen 0.2
Acrylamide/acrylic acid/dimethyldiallylammonium chloride copolymer liquid 2.0
Cellulose nanofiber 0.01～30.0
Amount to make 100 purified water.

Perm agent Perm agent 1 ammonium thioglycolate 4.0
Ammonia water (28%) 3.0
Monoethanolamine 2.0
Dicocoyldimethylammonium chloride 0.1
Stearyltrimethylammonium chloride 0.1
Laurylpyridinium chloride 0.1
Hydrolyzed wheat protein liquid 0.1
Propylene glycol 3.0
1,3-butylene glycol 3.0
Calcium disodium ethylenediaminetetraacetate 0.1
Dimethyldiallylammonium chloride/acrylic acid copolymer liquid 0.3
Polychlorinated dimethylmethylene piperidinium liquid 0.2
Cellulose nanofiber 0.01～30.0
Purified water ~83.7
Perm 2 agent Sodium bromate 5.0
Aminomethylaminopropylsiloxane dimethylsiloxane copolymer emulsion 3.0
Hydrolyzed elastin 0.2
Dipropylene glycol 1.0
glycerin 1.0
Hydroxyethylcellulose 0.1
Succinic acid 0.2
Disodium succinate 0.1
Citric acid 0.1
Acrylamide/acrylic acid/amidopropyltrimethylammonium chloride methacrylate copolymer liquid 0.2
Cellulose nanofiber 0.01～30.0
Purified water ~88.8.

Hair cream liquid paraffin 13.0
Vaseline 13.0
White beeswax 2.0
Polyoxyethylene hydrogenated castor oil 3.0
xanthan gum 2.0
O-(2-hydroxy-3-trimethylammoniopropyl)hydroxyethylcellulose chloride 2.0
Highly polymerized methylpolysiloxane 3.0
Methylsiloxane 3.0
Cellulose nanofiber 0.01～30.0
Purified water ~55.7
Preservative 1.0
Chelating agent 1.0
Dye 1.0.

Hair gel acrylic acid/acrylic acid/dimethyldiallylammonium chloride copolymer liquid 1-5
Carboxyvinyl polymer 0.5
Polyvinylpyrrolidone 1-5
Methyl polysiloxane 0.5
Glycerin Appropriate amount Neutralizing agent Appropriate amount Ethyl alcohol 10-30
Polyoxyethylene octyl dodecyl ether appropriate amount Cellulose nanofiber 0.01-30.0
UV absorber, appropriate amount, vitamin derivative, appropriate amount, natural extract, appropriate amount, chelating agent, appropriate amount, fragrance, appropriate amount, pigment, appropriate amount, preservative, appropriate amount Add purified water to make 100.0.

Sunscreen agent 1,3-butylene glycol 5.0
Squalane 40.0
Titanium oxide dispersion 3.0
UV absorber 1.0
Octyl paramethoxycinnamate 5.0
Cellulose nanofiber 0.01～30.0
Oxybenzone 3.0
Thickener 2.0
Preservative: Appropriate amount Flavor: Appropriate amount Color: Appropriate amount Add purified water to make 100.0.

Bath salts (capsule type)
Liquid paraffin 60.0
Squalane 10.0
Acrylic acid/acrylic acid/dimethyldiallylammonium chloride copolymer liquid 5.0
Cellulose nanofiber 0.01～30.0
Macadamia nut oil 10.0
Sorbitan Oleate 5.0
Vitamin derivatives Appropriate amount Flavors Appropriate amount Colorants Appropriate amount Preservatives Appropriate amount Add purified water to make 100.0.

capsule gelatin 41.0
Glycerin 18.0
Pigment Appropriate amount Add purified water to make 100.0.

Cream liquid paraffin 30.0
Microcrystalline wax 2.0
Vaseline 5.0
Sorbitan higher fatty acid ester 5.0
Cellulose nanofiber 0.01～30.0
Amino acid derivatives 2.0
Propylene glycol 5.0
Add purified water to make 100.0 Preservatives Appropriate amount Flavors Appropriate amount Colorants Appropriate amount.

foundation talc 3.0
Titanium dioxide 5.0
Red Garla 0.5
Yellow iron oxide 1.4
Black iron oxide 0.1
Bentonite 0.5
Polyoxyethylene sorbitan monostearate 0.9
Triethanolamine 1.0
Propylene glycol 10.0
Cellulose nanofiber 0.01～30.0
Add purified water to make 100.0 Stearic acid 2.2
Isohexadecyl alcohol 7.0
Glyceryl monostearate 2.0
liquid lanolin 2.0
Liquid paraffin 8.0
Appropriate amount of preservative.

2 layer foundation talc 7.0
Titanium dioxide 12.0
Silicic anhydride 2.0
Nylon powder 4.0
Colored pigment 2.0
Octamethylcyclotetrasiloxane 10.0
Rosin Pentaerythritol Ester 1.5
Neopentyl glycol diisooctoate 5.0
Squalane 2.5
Glycerin triisooctoate 2.0
Polyoxyethylene modified dimethyl polysiloxane 1.5
Add purified water to make 100.0 1,3-butylene glycol 4.0
Ethanol 7.0
Cellulose nanofiber 0.01-30.0.

Soap lauric acid monoglyceride sulfate ester soda salt 40.0
Cetyl alcohol 26.0
Glyceryl stearate 5.0
Glyceryl laurate 5.0
Cellulose nanofiber 0.01～30.0
Soap base 3.0
Acrylamide methylpropane sulfuric acid/acrylic acid copolymer liquid 3.0
Acrylic acid/acrylic acid/dimethyldiallylammonium chloride copolymer liquid 3.0
Sodium Coconut Oil Fatty Acid Ethyl Ester Sulfonate 3.0
Coconut oil fatty acids 2.0
Antioxidant appropriate amount Pigment appropriate amount Fragrance appropriate amount Pigment appropriate amount Natural extract appropriate amount Sequestering agent appropriate amount.

Hair dye liquid Hair dye 1st agent Cellulose nanofiber 0.01-30.0
Polyoxyethylene (2) oleyl ether 5.0-15.0
Polyoxyethylene (12) alkyl (12-14) ether 1.0-10.0
Oleic acid 1.0-5.0
Ammonia water (28%) 0.1-10.0
Monoethanolamine 0.1-10.0
Ammonium bicarbonate 0.1-5.0
Propylene glycol 5.0～15.0
Isopropyl alcohol 5.0-15.0
Sodium sulfite 0.1-1.0
Edetate disodium 0.1～1.0
Paraphenylenediamine 1.0
Resorcinol 1.0
Meta-aminophenol 0.5
Hydrochloric acid 2,4-diaminophenoxyethanol 0.5
Hydrolyzed collagen liquid 0.01-5.0
N-(2-hydroxy-3-trimethylammoniopropyl chloride) hydrolyzed keratin solution
0.01～5.0
N-(2-hydroxy-3-trimethylammoniopropyl) chloride hydrolyzed wheat protein liquid 0.01-5.0
Fragrance Appropriate amount Add purified water to make 100.0 Hair dye 2nd agent Cellulose nanofiber 0.01-30.0
Setanol 0.1～5.0
Sodium lauryl sulfate 0.01-2.0
Hydrogen peroxide solution (35%) 17.0
Phenacetin 0.05
Phosphoric acid Adjust the pH to 3. Add purified water to make it 100.0. Use after mixing the first and second parts in a 1/1 ratio.

Hair dye cream Hair dye 1st agent Setanol 5.0-15.0
Sodium lauryl sulfate 1.0-3.0
Polyoxyethylene (15) cetyl ether 0.5-3.0
Liquid paraffin 1.0-10.0
Jojoba oil 0.1-5.0
Olive oil 0.1-5.0
Methyl polysiloxane 0.1~5.0
Monoethanolamine 0.1-10.0
Triethanolamine 0.1-10.0
Ammonium bicarbonate 0.1-5.0
Propylene glycol 5.0～15.0
Ammonium thioglycolate 0.1-1.0
Tetrasodium edetate 0.1～1.0
Toluene-2,5,-diamine 1.0
Resorcinol 0.5
Meta-aminophenol 0.5
Para-aminophenol 0.3
Para-amino orthocresol 0.1
Dimethyldiallylammonium chloride/acrylic acid copolymer 0.01-5.0
Cellulose nanofiber 0.01～30.0
Mixed plant extract (1) 0.01-5.0
Mixed plant extract (3) 0.01-5.0
Mixed plant extract (6) 0.01-5.0
Fragrance Appropriate amount Add purified water to make 100.0 Hair dye 2nd agent Cellulose nanofiber 0.01-30.0
Setanol 5.0～15.0
Sodium lauryl sulfate 1.0-3.0
Polyoxyethylene (15) cetyl ether 0.5-3.0
Liquid paraffin 1.0-10.0
Hydrogen peroxide solution (35%) 17.0
Phenacetin 0.05
Citric acid Adjust the pH to 3 Add purified water to make it 100.0 Use after mixing the first and second parts in a 1/1 ratio.

Decolorizer <br/> Decolorizer 1st agent Cellulose nanofiber 0.01~30.0
Sodium polyoxyethylene lauryl ether sulfate 10.0~20.0
Coconut oil fatty acid diethanolamide 5.0-15.0
Polyoxypropylene butyl ether 5.0~15.0
Hexyldecanol 1.0～10.0
Oleic acid 1.0-5.0
Ammonia water (28%) 0.1-10.0
Monoethanolamine 0.1-10.0
Propylene glycol 1.0～10.0
Ethanol 5.0-15.0
Edetate disodium 0.1～1.0
Seaweed extract 0.01～5.0
Fragrance Appropriate amount Add purified water to make 100.0 Decolorizer 2nd agent Cellulose nanofiber 0.01-30.0
Setanol 0.1～5.0
Sodium lauryl sulfate 0.01-2.0
Hydrogen peroxide solution (35%) 17.0
Phenacetin 0.05
Phosphoric acid Adjust the pH to 3. Add purified water to make it 100.0. Use after mixing the first and second parts in a 1/1 ratio.

Decolorizer <br/> Decolorizer 1st agent Cellulose nanofiber 0.01~30.0
Setanol 5.0～15.0
Behenyltrimethylammonium chloride 1.0-3.0
Polyoxyethylene (2) cetyl ether 0.5-3.0
Liquid paraffin 1.0-10.0
Light liquid isoparaffin 1.0-5.0
Vegetable squalane 0.1-5.0
Highly polymerized methylpolysiloxane (1) 0.1-5.0
Ammonia water (28%) 0.1-10.0
Propylene glycol 5.0～15.0
Edetate disodium 0.1～1.0
Royal jelly extract 0.01～5.0
Calamus root extract 0.01～5.0
Cornflower extract 0.01-5.0
Purple cabbage extract 0.01～5.0
Fragrance Appropriate amount Add purified water to make 100.0 Decolorizer 2nd agent Cellulose nanofiber 0.01-30.0
Hydrogen peroxide solution (35%) 17.0
Phenacetin 0.05
Tartaric acid Adjust to pH 3 Add purified water to 100.0 Decolorizing agent 3rd agent Potassium persulfate 30.0 to 50.0
Ammonium persulfate 20.0-40.0
Anhydrous sodium metasilicate 10.0～30.0
Silicic anhydride 1.0-10.0
Add anhydrous sodium sulfate to make 100.0.

Whitening and skin care agent inositol 0.5
Dipotassium glycyrrhizinate 0.1
Niacinamide 0.15
Tocopherol acetate 0.1
Panthenol 0.3
Menthol 0.45
PCA Menthyl 0.2
Methylparaben 0.1
Bisethoxydiglycol cyclohexanedicarboxylate 1.0
Pentylene glycol 2.0
PEG-50 Isostearate Hydrogenated Castor Oil 2.4
Ethanol 15.0
Eucalyptus oil 0.2
Assemble extract 3.0
Panax ginseng extract 3.0
Na hydroxide 0.007
Cellulose nanofiber 0.01～30.0
Amount to make 100% purified water.

Claims (13)

An additive containing carboxymethylated cellulose nanofibers, wherein the carboxymethylated cellulose nanofibers have a cellulose I type crystallinity of 60% or more, a carboxymethyl substitution degree of 0.50 or less, and an average fiber The diameter is 3 nm to 20 nm, the aspect ratio is 80 or less, the transmittance of light at a wavelength of 660 nm is 70% or more when made into an aqueous dispersion with a solid content of 1% (w/v), and the solid content is 3 nm to 20 nm. The viscosity at 25°C and 6 rpm when made into a 1% (w/v) water dispersion is A, and the viscosity at 25°C and 60 rpm when made into an aqueous dispersion with a solid content of 1% (w/v) is B. An additive containing carboxymethylated cellulose nanofibers , in which A/B is 6.0 or more . Carboxymethylated cellulose nanofibers are produced by carrying out a mercerization reaction in a solvent mainly composed of water, and then carrying out a carboxymethylation reaction in a mixed solvent of water and an organic solvent. The additive according to claim 1, which is obtained by defibrating. The additive according to claim 2, wherein the water-based solvent is a solvent containing more than 50% by mass of water. The additive according to any one of claims 1 to 3 , which is a cosmetic additive. The additive according to any one of claims 1 to 3 , which is a food additive. The additive according to any one of claims 1 to 3 , which is an additive for pharmaceuticals or quasi-drugs. The additive according to any one of claims 1 to 3 , which is a feed additive. The additive according to any one of claims 1 to 3 , which is a papermaking additive. The additive according to any one of claims 1 to 3 , which is an additive for paints. The additive according to any one of claims 1 to 3 , which is a water retention agent. The additive according to any one of claims 1 to 3 , which is a shape retention imparting agent. The additive according to any one of claims 1 to 3 , which is a viscosity modifier. The additive according to any one of claims 1 to 3 , which is an emulsion stabilizer or a dispersion stabilizer.