Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B15/00—Preparation of other cellulose derivatives or modified cellulose, e.g. complexes
  • C08B15/02—Oxycellulose; Hydrocellulose; Cellulosehydrate, e.g. microcrystalline cellulose
  • C08B15/04—Carboxycellulose, e.g. prepared by oxidation with nitrogen dioxide
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
  • C08L1/02—Cellulose; Modified cellulose
  • C08L1/04—Oxycellulose; Hydrocellulose, e.g. microcrystalline cellulose
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/001—Modification of pulp properties
  • D21C9/007—Modification of pulp properties by mechanical or physical means
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
  • D21H11/18—Highly hydrated, swollen or fibrillatable fibres
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
  • D21H11/20—Chemically or biochemically modified fibres
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
  • C08K2003/0893—Zinc
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
  • C08K2003/2296—Oxides; Hydroxides of metals of zinc

Definitions

• the present invention relates to a method for producing a nanocellulose-containing composition.
• CNF cellulose nanofibers
• Patent Document 1 hypochlorous acid or a salt thereof is used as an oxidizing agent, and a cellulose-based raw material is oxidized to obtain oxidized cellulose under a high concentration condition in which the effective chlorine concentration in the reaction system is 14 to 43% by mass. , It is disclosed that CNF is obtained by finely treating the oxidized cellulose. Further, in Patent Document 2, hypochlorous acid or a salt thereof is used as an oxidizing agent, the effective chlorine concentration in the reaction system is 6 to 14% by mass, and the pH is adjusted to 5.0 to 14.0 for cellulose. It is disclosed that after oxidizing a system raw material to obtain cellulose oxide, the cellulose oxide is micronized to obtain CNF.
• the N-oxyl compound is used because the oxidation treatment is performed without using an N-oxyl compound such as 2,2,6,6-tetramethyl-1-piperidin-N-oxyradic (TEMPO) as a catalyst. Since it does not remain in the cellulose fiber, it is possible to produce the nano-cellulose material while reducing the influence on the environment and the like.
• TEMPO 2,2,6,6-tetramethyl-1-piperidin-N-oxyradic
• Patent Document 3 describes a production method including a step of defibrating pulp having a degree of polymerization of cellulose of 100 to 500 in a defibrated resin to obtain a cellulose nanofiber and a resin composition containing the defibrated resin. ing. Further, in Patent Document 4, an acetylated cellulose fiber and a resin for a masterbatch are mixed and kneaded at a heating temperature in a twin-screw kneader to obtain an acetylated cellulose nanofiber derived from the acetylated cellulose fiber and a masterbatch resin. A method for producing a masterbatch containing a resin is described.
• Patent Documents 1 and 2 as a specific example of producing a nanocellulose material by refining cellulose oxide, a nanocellulose material (simply nanocellulose) is subjected to mechanical defibration treatment by mechanical treatment using an ultrasonic homogenizer.
• An example of obtaining (also referred to as) is disclosed.
• the nanocellulose thus obtained is compounded with other materials according to various uses.
• the nanocellulose obtained as described above causes an increase in production cost and a decrease in production efficiency due to the inclusion of mechanical defibration treatment. Therefore, there are problems of efficiency such as cost increase and productivity even in the production of a compound compounded with other materials.
• Patent Documents 3 and 4 describe a method of defibrating pulp or acetylated cellulose fibers in a resin to form cellulose nanofibers.
• the cellulose fibers used in this method are pulp itself or modified cellulose fibers, and defibration requires an energy load, so that a resin composition containing nanocellulose cannot be efficiently obtained.
• the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for efficiently obtaining a nanocellulose-containing composition.
• the present inventors have found that by using a predetermined cellulose oxide, a nanocellulose-containing composition can be efficiently obtained by omitting the step of mechanical defibration treatment for refining the oxidized cellulose. , The present invention has been completed. According to the present invention, the following means are provided.
• a method for producing a composition containing nanocellulose A step of defibrating the oxidized cellulose into the nanocellulose by stirring a mixture containing the oxidized cellulose and components other than the nanocellulose constituting the composition is included.
• the oxidized cellulose contains an oxide of a cellulosic raw material due to hypochlorous acid or a salt thereof.
• Production method [2] The production method according to [1], wherein the mixture further contains a dispersion medium.
• a method for producing a composition containing nanocellulose A step of defibrating the oxidized cellulose into the nanocellulose by stirring the oxidized cellulose and continuously adding components other than the nanocellulose constituting the composition is included.
• the oxidized cellulose contains an oxide of a cellulosic raw material due to hypochlorous acid or a salt thereof.
• Production method [4] The production method according to [3], wherein the stirring of the oxidized cellulose and the addition of the components are performed in one pot. [5] The production method according to [3] or [4], wherein the oxidized cellulose is dispersed in a dispersion medium. [6] The production method according to any one of [1] to [5], wherein the oxidized cellulose does not substantially contain an N-oxyl compound. [7] The production method according to any one of [1] to [6], wherein the degree of polymerization of the oxidized cellulose is 600 or less.
• a nanocellulose-containing composition containing nanocellulose and a compound can be efficiently obtained.
• the production method of the present invention is a method for producing a nanocellulose-containing composition containing nanocellulose and at least one compound.
• One aspect of the production method of the present invention is It comprises a step of defibrating cellulose oxide into nanocellulose by stirring a mixture containing cellulose oxide and components other than nanocellulose (also referred to as “combination”) constituting the composition.
• the component that is agitated together with the oxidized cellulose may be a part or all of the components (excluding nanocellulose) constituting the composition.
• the remaining components may be added after stirring.
• one aspect of the manufacturing method of this invention is The process of preparing cellulose oxide, A step of obtaining a mixture of the oxidized cellulose and at least one compound, and The step of stirring the mixture to obtain a nanocellulose-containing composition is included.
• the above-mentioned embodiment in which oxidized cellulose is defibrated in the presence of other components is also referred to as a production method I. It is preferable that the composition in the production method I does not consist only of nanocellulose and a dispersion medium.
• One aspect of the production method of the present invention is A step of defibrating the oxidized cellulose into nanocellulose by stirring the oxidized cellulose and continuously mixing components other than the nanocellulose constituting the composition is included.
• one aspect of the manufacturing method of this invention is The process of preparing cellulose oxide, The step of stirring the oxidized cellulose and continuously adding at least one compound to obtain a nanocellulose-containing composition is included.
• the above-mentioned embodiment in which the oxidized cellulose is defibrated and continuously mixed with other components is also referred to as a production method II.
• the cellulose oxide in the present invention contains an oxide of a cellulosic raw material due to hypochlorous acid or a salt thereof.
• the mechanical defibration treatment is finally performed.
• the present inventors have found that the oxidized cellulose obtained by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof is excellent in defibration. Further, the present inventors have found that the above-mentioned oxidized cellulose can be induced to nanocellulose even with a slight stirring without using a mechanical defibration treatment device used for obtaining conventional nanocellulose.
• nanocellulose has been used when mixing or compounding nanocellulose with other materials, but according to the production method of the present invention, oxidized cellulose is added when the other materials are dispersed or emulsified.
• the above-mentioned oxidized cellulose becomes nanocellulose even with slight stirring, and as a result, other materials and nanocellulose can be mixed or complexed.
• the nanocellulose-containing composition can be obtained by omitting the step of mechanically defibrating, and is excellent in efficiency.
• the oxidized cellulose can be defibrated and made fine by stirring.
• a nanocellulose-containing composition containing nanocellulose and at least one formulation is obtained.
• the stirring in the present invention is not particularly limited as long as it can micronize at least a part of the oxidized cellulose, and may be normal stirring. Further, the stirring in the present invention is not particularly limited as long as it is an operation for dispersing the components constituting the nanocellulose-containing composition.
• the cellulose oxide may be finely divided to such an extent that the function of nanocellulose can be obtained, and some of the oxidized cellulose may remain without being finely divided. Therefore, the nanocellulose-containing composition obtained by the production method of the present invention may contain a part of oxidized cellulose.
• the order and method of adding these are not particularly limited.
• the oxidized cellulose is stirred and at least one compound is continuously added. More specifically, one aspect of the production method II of the present invention is a production method in which the oxidized cellulose is stirred to make at least a part finer, and then at least one compound is continuously added.
• “continuously” means that at least a part of the oxidized cellulose is refined by stirring and the compound is added in a series.
• Specific embodiments in which stirring and addition of a compound are performed in a series include, for example, a mode in which the stirring of cellulose oxide to be finely divided and the addition of at least one compound are operated in one pot; cellulose oxide. A mode in which at least one compound is added at the same time while stirring the above; and the like, but the present invention is not limited thereto. In this way, the user of cellulose oxide can obtain nanocellulose by micronizing the cellulose oxide by himself and use it.
• the stirring in the present invention is not particularly limited as long as it is an operation for dispersing the components constituting the nanocellulose-containing composition, and for example, a velocity field and a velocity fluctuation of arbitrary intensity; to inclusions and obstacles. Collision; ultrasonic; pressure load; etc. can be utilized.
• a liquid disperser can be preferably used for such a dispersion operation. Therefore, one aspect of the production method of the present invention is a production method in which stirring is performed by a liquid disperser.
• the liquid disperser is not particularly limited, and for example, a homomixer, a magnetic stirrer, a stirring rod, a stirrer with a stirring blade, a disper type mixer, a homogenizer, an external circulation stirrer, a rotating revolution stirrer, a vibration type stirrer, and the like.
• a method using an ultrasonic disperser or the like can be mentioned.
• the liquid disperser in addition to the above-mentioned apparatus, a rotary shear type agitator, a colloidal mill, a roll mill, a pressure homogenizer, a container-driven mill, a medium agitation mill and the like can be mentioned. Further, a kneader can be used as the liquid disperser.
• the rotary shear type stirrer is a device that disperses by passing an object to be agitated through the gap between the rotary blade and the outer cylinder, and disperses by the shear flow in the gap and the strong velocity fluctuation before and after.
• the peripheral speed of the tip of the rotary blade is not particularly limited, but is usually 100 m / s or less.
• the peripheral speed is preferably 50 m / s or less, more preferably 30 m / s or less, and further preferably 15 m / s or less from the viewpoint of cost and production efficiency.
• the lower limit of the peripheral speed is not particularly limited, but usually may exceed 0 m / s.
• a colloid mill is a device that disperses by shear flow in the gap between a rotating disk and a fixed disk.
• a roll mill is a device that disperses by shearing force and compressive force utilizing the gap between a plurality of rotating rolls.
• the pressure homogenizer is used as a disperser that discharges slurry or the like from pores at high pressure, and is also called a pressure injection disperser.
• a high pressure homogenizer is preferable.
• the high-pressure homogenizer refers to a homogenizer having an ability to discharge a slurry at a pressure of, for example, 10 MPa or more, preferably 100 MPa or more.
• the upper limit of the pressure of the high-pressure homogenizer is not particularly limited, but may be 400 MPa or less.
• the upper limit of the pressure of the high-pressure homogenizer is preferably 200 MPa or less, more preferably 100 MPa or less, still more preferably 50 MPa or less, still more preferably 30 MPa or less, from the viewpoint of cost and production efficiency.
• the high-pressure homogenizer include a counter-collision type high-pressure homogenizer such as a microfluidizer and a wet jet mill.
• the container-driven mill is a device that disperses due to collision and friction of a medium such as a ball in the container, and specifically, there are a rotary mill, a vibration mill, a planetary mill, and the like.
• the medium stirring mill is a device that uses a medium such as a ball or a bead and disperses by the impact force and the shearing force of the medium, and specifically, there are an attritor and a bead mill (sand mill).
• a kneader is a device that wets powder or the like with a liquid (also called kneading or kneading). Specifically, it is a double-armed kneader (biaxial in two semi-cylindrical containers). (It is a device that disperses by the mixing blades of
• These devices may be used alone or in combination of two or more.
• the miniaturization of oxidized cellulose can be promoted by stirring using such an apparatus, stirring may be performed until the constituent components of the nanocellulose-containing composition are homogenized or emulsified. Thereby, the nanocellulose is uniformly dispersed in the nanocellulose-containing composition, and the nanocellulose-containing composition can be obtained as an emulsion.
• Stirring is preferably carried out in a state where cellulose oxide is mixed with the dispersion medium. Therefore, it is preferable that the mixture containing the oxidized cellulose and at least one compound in the production method I further contains a dispersion medium. Further, it is preferable that the cellulose oxide in the production method II is dispersed in a dispersion medium.
• the dispersion medium is not particularly limited and may be appropriately selected depending on the intended purpose. Specific examples of the dispersion medium include water, alcohols, ethers, ketones, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide and the like. As the solvent, one of these may be used alone, or two or more of them may be used in combination.
• alcohols include methanol, ethanol, isopropanol, isobutanol, sec-butyl alcohol, tert-butyl alcohol, methyl cellosolve, ethylene glycol, glycerin and the like.
• ethers include ethylene glycol dimethyl ether, 1,4-dioxane and tetrahydrofuran.
• ketone include acetone, methyl ethyl ketone and the like.
• the concentration of cellulose oxide at the time of stirring may be appropriately adjusted according to the stirring device and the type of the mixture, but the object to be stirred (in the production method I, at least 1 with the oxidized cellulose).
• a mixture containing a mixture of seeds and a dispersion medium and in Production Method II, refers to a dispersion liquid containing cellulose oxide and a dispersion medium.
• the rotation speed may be usually in the range of 100 rpm to 1,000 ⁇ 10 3 rpm. From the viewpoint of promoting miniaturization more efficiently, the rotation speed is preferably in the range of 1,000 rpm to 100,000 rpm.
• the stirring time is not particularly limited, but is preferably in the range of 1 minute to 1 hour from the viewpoint of productivity.
• the concentration of cellulose oxide is preferably in the range of 0.1 to 30% by mass with respect to the total amount of the object to be stirred.
• the concentration of the oxidized cellulose is in the range of 0.1 to 30% by mass, the miniaturization tends to proceed more easily, and the nanocellulose-containing composition tends to be obtained more efficiently.
• the concentration of cellulose oxide is more preferably 1.0% by mass or more and 30% by mass or less, still more preferably 1.5% by mass or more and 20% by mass or less, still more preferably 1.5% by mass. It is by mass% or more and 15% by mass or less.
• the rotation / revolution stirrer is a device that mixes the materials in the container by rotating and revolving the container into which the material is charged. According to the planetary rotation mixer, stirring is performed without using a stirring blade.
• the revolution speed and the rotation speed at the time of stirring by the rotation revolution stirrer can be appropriately set.
• the revolution speed can be set to 400 to 3000 rpm and the rotation speed can be set to 200 to 1500 rpm.
• the revolution speed is more preferably 1500 to 2300 rpm, and the rotation speed is more preferably 700 to 950 rpm.
• the concentration of cellulose oxide is, for example, 0.01 to 1.0% by mass, preferably 0.1 to 0.5% by mass.
• the vibration type agitator examples include a vortex mixer (touch mixer).
• a vortex mixer stirring is performed by forming a vortex in the liquid material in the container.
• agitation is performed without using a stirring blade, so that milder agitation can be realized.
• mild agitation can be realized by simple equipment, which is excellent in terms of production equipment and production cost.
• the rotation speed of the vortex mixer is, for example, 600 to 3000 rpm, and it is preferable to perform the vortex mixer under the condition of stirring for 3 to 15 minutes.
• the concentration of the aqueous dispersion of cellulose oxide as a material is, for example, 0.01 to 1.0% by mass, preferably 0.1 to 0.5% by mass.
• the step of preparing the oxidized cellulose in the present invention is not particularly limited, and the oxidized cellulose may be obtained and used as a ready-made product such as a commercially available product, and is oxidized from a cellulosic raw material using hypochlorous acid or a salt thereof. May be prepared.
• the form of the oxidized cellulose may be, for example, a solid (dry) form, a slurry form, or the like. Although not particularly limited, it is preferably in the form of a slurry. That is, it is preferable that the oxidized cellulose is prepared as a slurry.
• the slurry referred to here is a suspension containing cellulose oxide.
• the slurry may contain the solvent used in preparing the oxidized cellulose. Further, the above-mentioned dispersion medium may be appropriately added to form a slurry. Since the cellulose oxide is a slurry, it is easy to handle and miniaturization tends to proceed easily.
• the amount of cellulose oxide is usually in the range of 0.1% by mass or more and 95% by mass or less, preferably 1% by mass or more, when the total amount of the slurry is 100% by mass. It is 50% by mass or less, more preferably 1% by mass or more and 30% by mass or less.
• the oxidized cellulose in the present invention contains fibrous cellulose obtained by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof.
• Oxidized cellulose is an oxide of a cellulosic raw material and means one before defibration treatment (miniaturization treatment).
• the cellulose oxide in the present invention is also referred to as a cellulose oxide fiber. That is, the oxidized cellulose in the present invention contains an oxide of a cellulosic raw material by hypochlorous acid or a salt thereof.
• the main component of the plant is cellulose, and a bundle of cellulose molecules is called a cellulose microfibril. Cellulose in cellulosic raw materials is also contained in the form of cellulosic microfibrils.
• the degree of polymerization of cellulose oxide may be 600 or less.
• the degree of polymerization of cellulose oxide is 600 or less, a large amount of energy tends to be unnecessary for defibration, and sufficient defibration tends to be exhibited.
• the composition can be refined under mild conditions and can be refined by ordinary stirring or kneading, and there is a tendency to efficiently obtain a nanocellulose-containing composition.
• the lower limit of the degree of polymerization of the present oxidized cellulose is not particularly set.
• the degree of polymerization of cellulose oxide is 30 or more, the proportion of particulate cellulose rather than fibrous is small, the quality of the slurry containing the oxidized cellulose becomes uniform, the viscosity becomes stable, and the nanocellulose It becomes easier to obtain the viscosity property, which is one of the features.
• the degree of polymerization of cellulose oxide is preferably 30 to 600.
• the degree of polymerization is more preferably 580 or less, still more preferably 560 or less, even more preferably 550 or less, still more preferably 500 or less, even more preferably 450 or less, and even more preferably. It is 400 or less.
• the lower limit of the degree of polymerization is more preferably 50 or more, further preferably 60 or more, still more preferably 70 or more, still more preferably 80 or more, from the viewpoint of improving the viscosity stability of the slurry. It is even more preferably 90 or more, even more preferably 100 or more, particularly preferably 110 or more, and most preferably 120 or more.
• the preferable range of the degree of polymerization can be determined by appropriately combining the above-mentioned upper limit and lower limit.
• the degree of polymerization of cellulose oxide is more preferably 50 to 600, still more preferably 60 to 600, still more preferably 80 to 600, still more preferably 80 to 550, and even more preferably 80 to 80. It is 500, more preferably 80 to 450, and particularly preferably 80 to 400.
• the degree of polymerization of cellulose oxide can be adjusted by changing the reaction time, reaction temperature, pH, and the effective chlorine concentration of hypochlorous acid or a salt thereof during the oxidation reaction. Specifically, since the degree of polymerization tends to decrease as the degree of oxidation increases, for example, a method of increasing the reaction time and / or the reaction temperature of oxidation can be mentioned in order to reduce the degree of polymerization. As another method, the degree of polymerization of cellulose oxide can be adjusted by the stirring conditions of the reaction system at the time of the oxidation reaction. For example, under conditions in which the reaction system is sufficiently homogenized using a stirring blade or the like, the oxidation reaction proceeds smoothly and the degree of polymerization tends to decrease.
• the degree of polymerization of cellulose oxide tends to vary depending on the selection of the cellulosic raw material. Therefore, the degree of polymerization of oxidized cellulose can be adjusted by selecting a cellulosic raw material.
• the degree of polymerization of cellulose oxide is the average degree of polymerization (viscosity average degree of polymerization) measured by the viscosity method. For details, follow the method described in Examples described later.
• the amount of carboxy group of cellulose oxide is preferably 0.30 to 2.0 mmol / g.
• the amount of the carboxy group is 0.30 mmol / g or more, sufficient defibability can be imparted to the oxidized cellulose. As a result, it can be miniaturized under mild conditions, and tends to be miniaturized by ordinary stirring or kneading.
• the amount of carboxy group is 2.0 mmol / g or less, it is possible to suppress excessive decomposition of oxidized cellulose when blended with other components, the ratio of particulate cellulose is small, and the quality of nanocellulose is uniform. Can be obtained.
• the amount of carboxy group of cellulose oxide is more preferably 0.35 mmol / g or more, further preferably 0.40 mmol / g or more, still more preferably 0.42 mmol / g or more, and further. It is more preferably 0.50 mmol / g or more, still more preferably 0.50 mmol / g or more, even more preferably 0.55 mmol / g or more, and even more preferably 0.60 mmol / g.
• the upper limit of the amount of carboxy group is more preferably 1.5 mmol / g or less, still more preferably 1.2 mmol / g, still more preferably 1.0 mmol / g or less, and even more preferably 0.
• the preferable range of the amount of carboxy group can be determined by appropriately combining the above-mentioned upper limit and lower limit.
• the amount of the carboxy group of the present oxidized cellulose is more preferably 0.35 to 2.0 mmol / g, further preferably 0.35 to 1.5 mmol / g, still more preferably 0.40 to 1.5 mmol. / G, even more preferably 0.50 to 1.2 mmol / g, even more preferably over 0.50 to 1.2 mmol / g, and even more preferably 0.55 to 1.0 mmol / g. It is even more preferably 0.60 to 0.80 mmol / g.
• the amount of carboxy group (mmol / g) in cellulose oxide is adjusted to pH 2.5 by adding 0.1 M (hereinafter, also referred to as mol / L) aqueous hydrochloric acid solution to an aqueous solution of cellulose oxide mixed with water.
• a 0.05 N aqueous solution of sodium hydroxide was added dropwise, the electric conductivity was measured until the pH reached 11.0, and the amount of sodium hydroxide consumed in the neutralization step of the weak acid with a gentle change in the electric conductivity ( It is a value calculated from a) using the following formula.
• the amount of carboxy group can be measured according to the method described in Examples described later.
• one aspect of the cellulose oxide used in the present invention is to solve the water dispersion having a concentration of 0.1% by mass of the cellulose oxide under the conditions of a rotation speed of 2000 rpm and a rotation speed of 800 rpm for 10 minutes using a rotation revolution stirrer.
• the light transmittance of the nanocellulose aqueous dispersion obtained by the fiber treatment shows a value of 60% or more.
• the light transmittance of this nanocellulose aqueous dispersion is more preferably 70% or more, further preferably 75% or more, still more preferably 80% or more.
• the light transmittance is a value measured by a spectrophotometer at a wavelength of 660 nm. Specifically, the light transmittance can be measured according to the method described in Examples described later.
• the cellulose oxide used in the present invention is nanocellulose aqueous dispersion obtained by defibrating a water dispersion having a concentration of 0.1% by mass of the oxidized cellulose with a vortex mixer at a rotation speed of 3000 rpm for 10 minutes. It is preferable that the light transmittance of the liquid shows a value of 60% or more.
• the light transmittance of this nanocellulose aqueous dispersion is more preferably 70% or more, further preferably 75% or more, still more preferably 80% or more.
• the oxidized cellulose in the present invention is obtained by oxidation using hypochlorous acid or a salt thereof, and the oxidized cellulose thus obtained preferably contains at least two of the hydroxyl groups of the glucopyranose ring constituting the cellulose. It has an oxidized structure, and more specifically, it has a structure in which the hydroxyl groups at the 2- and 3-positions of the glucopyranose ring are oxidized and a carboxy group is introduced. Further, it is preferable that the hydroxyl group at the 6-position of the glucopyranose ring in the nanocellulose or oxidized cellulose is not oxidized and remains as a hydroxyl group.
• the position of the carboxy group in the glucopyranose ring of cellulose oxide can be analyzed by comparing the solution NMR spectrum using rayon oxide as a model molecule and the solid 13 C-NMR spectrum of cellulose oxide.
• Rayon has the same chemical structure as cellulose, and its oxide (rayon oxide) is water-soluble.
• rayon oxide By dissolving rayon oxide in heavy water and performing one-dimensional 13 C-NMR measurement of the solution, a peak of carbon attributed to the carboxy group is observed at 165 to 185 ppm.
• oxidized cellulose or nanocellulose obtained by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof used in the present invention, two signals appear in this chemical shift range. Further, by solution two-dimensional NMR measurement, it can be determined that the carboxy group is introduced at the 2-position and the 3-position.
• two peak area values obtained by vertically dividing the area value at the peak top after drawing a baseline on the peak in the range of 165 ppm to 185 ppm in the solid 13 C-NMR spectrum to obtain the total area value.
• a ratio large area value / small area value
• the ratio of the peak area values is 1.2 or more, it can be said that the peak is broad.
• the presence or absence of the broad peak can be determined by the ratio of the baseline length L in the range of 165 ppm to 185 ppm and the perpendicular length L'from the peak top to the baseline. That is, if the ratio L'/ L is 0.1 or more, it can be determined that a broad peak exists.
• the ratio L'/ L may be 0.2 or more, 0.3 or more, 0.4 or more, or 0.5 or more.
• the upper limit of the ratio L'/ L is not particularly limited, but usually it may be 3.0 or less, 2.0 or less, or 1.0 or less.
• the structure of the glucopyranose ring can also be determined by analysis according to the method described in Sustainable Chem. Eng. 2020, 8, 48, 17800-17806.
• the nanocellulose or oxidized cellulose used in the present invention contains a carboxy group, it includes a salt type, a proton type, and a modified type by a modifying group.
• the modifying group is not particularly limited as long as it is a compound capable of forming an ionic bond or a covalent bond with the carboxy group or hydroxyl group of nanocellulose or oxidized cellulose.
• the physical characteristics of nanocellulose or oxidized cellulose can be adjusted by adjusting the aspect of the carboxy group.
• Examples of the compound having a modifying group capable of forming an ionic bond include a primary amine, a secondary amine, a tertiary amine, a quaternary ammonium compound, and a phosphonium compound.
• Compounds having a modifying group capable of forming a covalent bond include, for example, alcohols, isocyanate compounds, and epoxy compounds.
• the cellulose oxide in the present invention is prepared without the need to use an N-oxyl compound such as TEMPO.
• N-oxyl compound such as TEMPO.
• the oxidized cellulose and the nanocellulose in the present invention do not substantially contain the N-oxyl compound.
• substantially free of N-oxyl compound means that the N-oxyl compound is not used at the time of oxidation, or the oxidized cellulose or nanocellulose is used.
• the content of nitrogen derived from the N-oxyl compound in the compound is 2.0% by mass or less, preferably 1.0% by mass or less as an increase from the cellulose-based raw material.
• N-oxyl compound is substantially contained. It means "not included”.
• the residual nitrogen component can be measured by using a trace total nitrogen analyzer, and more specifically, by the method described in Examples.
• Oxidized cellulose can be produced by a method including a step of oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof.
• the cellulosic raw material is not particularly limited as long as it is a material mainly composed of cellulose, and examples thereof include pulp, natural cellulose, regenerated cellulose, and fine cellulose depolymerized by mechanically treating cellulose.
• cellulose-based raw material a commercially available product such as crystalline cellulose made from pulp can be used as it is.
• unused biomass containing a large amount of cellulose components such as okara and soybean skin may be used as a raw material.
• the cellulosic raw material may be treated with an alkali having an appropriate concentration in advance.
• fine cellulose obtained by mechanically or chemically treating cellulose as a cellulose-based raw material.
• powdered pulp can be preferably mentioned.
• the particle size of the powdered pulp is usually in the range of 1 to 1000 ⁇ m, preferably in the range of 1 to 500 ⁇ m, and more preferably in the range of 1 to 100 ⁇ m.
• the particle size referred to here is an average particle size, and means a value when the volume accumulation distribution is 50% when the laser scattering method is used as a measurement principle and the particle size distribution is expressed as a volume accumulation distribution. ..
• hypochlorous acid or a salt thereof used for oxidation of cellulose-based raw materials examples include hypochlorous acid water, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, and ammonium hypochlorite. Can be mentioned. Of these, sodium hypochlorite is preferable from the viewpoint of ease of handling.
• Examples of the method for producing oxidized cellulose by oxidizing a cellulosic raw material include a method of mixing a cellulosic raw material with a reaction solution containing hypochlorous acid or a salt thereof.
• the solvent contained in the reaction solution is preferably water because it is easy to handle and side reactions are unlikely to occur.
• hypochlorous acid or a salt thereof having an effective chlorine concentration of 6% by mass or more and 43% by mass or less.
• hypochlorous acid or a salt thereof having an effective chlorine concentration of 6% by mass or more and 43% by mass or less By using hypochlorous acid or a salt thereof having an effective chlorine concentration of 6% by mass or more and 43% by mass or less, the amount of carboxy groups in the oxidized cellulose can be sufficiently increased, the miniaturization proceeds sufficiently, and after the oxidation reaction.
• the mechanical defibration process can be omitted.
• the effective chlorine concentration of hypochlorous acid or a salt thereof in the reaction solution (reaction system)
• the effective chlorine concentration is more preferably 7% by mass or more, further preferably 10% by mass or more, still more preferably 14% by mass or more, still more preferably 15% by mass. % Or more, more preferably 18% by mass or more, still more preferably 20% by mass or more. Further, from the viewpoint of suppressing excessive decomposition of cellulose, the effective chlorine concentration of the reaction solution is more preferably 40% by mass or less, still more preferably 38% by mass or less.
• the range of the effective chlorine concentration of the reaction solution can be appropriately combined with the above-mentioned lower limit and upper limit.
• the range of the effective chlorine concentration is more preferably 7 to 43% by mass, still more preferably 14 to 43% by mass.
• hypochlorous acid is a weak acid that exists as an aqueous solution
• hypochlorite is a compound in which hydrogen of hypochlorous acid is replaced with another cation.
• sodium hypochlorite which is a hypochlorite
• the concentration is measured not as the concentration of sodium hypochlorite but as the amount of effective chlorine in the solution. ..
• sodium hypochlorite since the oxidizing power of the divalent oxygen atom generated by the decomposition of sodium hypochlorite corresponds to the diatomic equivalent of monovalent chlorine, sodium hypochlorite is used.
• the sample is precisely weighed, water, potassium iodide and acetic acid are added and left to stand, and the free iodine solution is titrated with a sodium thiosulfate solution using an aqueous starch solution as an indicator to measure the effective chlorine concentration. do.
• the oxidation reaction of the cellulosic raw material with hypochlorous acid or a salt thereof should be carried out while adjusting the pH to the range of 5.0 or more. Within this range, the oxidation reaction of the cellulosic raw material can be sufficiently advanced, the amount of carboxy groups in the oxidized cellulose is sufficiently large, and the miniaturization by stirring tends to proceed easily.
• the pH of the reaction system is more preferably 7.0 or higher, still more preferably 8.0 or higher.
• the upper limit of the pH of the reaction system is not particularly limited, and is preferably 14.5 or less, more preferably 14.0 or less, still more preferably 13.0 or less.
• the pH range of the reaction system is more preferably 7.0 to 14.0, still more preferably 8.0 to 13.5.
• hypochlorite sodium hypochlorite is used as hypochlorous acid or a salt thereof.
• the reaction solution is preferably an aqueous solution of sodium hypochlorite.
• a method of adjusting the effective chlorine concentration of the aqueous sodium hypochlorite solution to the target concentration for example, target concentration: 6% by mass to 43% by mass
• sodium hypochlorite having a lower effective chlorine concentration than the target concentration is used.
• a method for concentrating an aqueous solution, a method for diluting an aqueous solution of sodium hypochlorite having an effective chlorine concentration higher than the target concentration, and a method using crystals of sodium hypochlorite (for example, sodium hypochlorite pentahydrate) as a solvent for example, sodium hypochlorite pentahydrate
• Examples thereof include a method of dissolving.
• adjusting the concentration of effective chlorine as an oxidant by a method of diluting an aqueous solution of sodium hypochlorite or a method of dissolving crystals of sodium hypochlorite in a solvent has less self-decomposition (that is, that is). There is little decrease in the effective chlorine concentration), and it is preferable because it is easy to adjust the effective chlorine concentration.
• the method of mixing the cellulosic raw material and the sodium hypochlorite aqueous solution is not particularly limited, but from the viewpoint of ease of operation, it is preferable to add the cellulosic raw material to the sodium hypochlorite aqueous solution and mix them.
• the stirring method include a magnetic stirrer, a stirring rod, a stirring machine with a stirring blade (three-one motor), a homomixer, a dispenser type mixer, a homogenizer, and external circulation stirring.
• shear stirrers such as homomixers and homogenizers, stirrers with stirring blades, and stirrers with stirring blades are available because the oxidation reaction of the cellulosic raw material proceeds smoothly and the degree of polymerization of the oxidized cellulose can be easily adjusted to a predetermined value or less.
• a method using one or more of the disper type mixers is preferable, and a method using a stirrer with a stirring blade is particularly preferable.
• a stirrer with a stirrer blade a device equipped with a known stirrer blade such as a propeller blade, a paddle blade, and a turbine blade can be used as the stirrer.
• a stirrer with a stirring blade it is preferable to perform stirring at a rotation speed of 50 to 300 rpm.
• the reaction temperature in the oxidation reaction is preferably 15 ° C to 100 ° C, more preferably 20 ° C to 90 ° C.
• an alkaline agent for example, sodium hydroxide or the like
• an acid for example, hydrochloric acid or the like
• the reaction time of the oxidation reaction can be set according to the degree of progress of oxidation, but is preferably about 15 minutes to 50 hours.
• the pH of the reaction system is 10 or more, it is preferable to set the reaction temperature to 30 ° C. or higher and / or the reaction time to 30 minutes or longer.
• the concentration of the cellulose-based raw material during the oxidation reaction is preferably 30 with respect to the total amount of the reaction mixture during the oxidation reaction from the viewpoint of improving workability such as facilitating stirring during the oxidation reaction and from the viewpoint of advancing miniaturization. It is mass% or less, more preferably 20% by mass or less, still more preferably 10% by mass or less.
• the lower limit of the concentration of the cellulosic raw material in the oxidation reaction is usually 0.1% by mass or more, and from the viewpoint of productivity, it is preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably. 3% by mass or more.
• the concentration of the cellulosic raw material in the oxidation reaction is preferably in the range of 0.1% by mass or more and 30% by mass or less, more preferably in the range of 1% by mass or more and 20% by mass or less, and further preferably 1% by mass. It is in the range of% or more and 10% by mass or less.
• a treatment for stopping the oxidation reaction may be performed.
• the treatment for stopping the oxidation reaction is not particularly limited, and examples thereof include a method of adding an acid or a metal catalyst. Further, a method of reducing hypochlorous acid or a salt thereof is preferably mentioned. Specific examples of the treatment for stopping the oxidation reaction include a method of adding a reducing agent such as sodium sulfite. The amount of the reducing agent added may be appropriately adjusted according to the amount of hypochlorous acid or a salt thereof (effective chlorine concentration).
• a known isolation treatment such as centrifugation or filtration is performed, and further purification is performed as necessary to obtain a cellulosic raw material using hypochlorous acid or a salt thereof.
• Oxidized cellulose can be obtained as an oxide of. Further, the solution containing the oxidized cellulose obtained by the above reaction may be directly applied to the next step.
• the nanocellulose-containing composition of the present invention contains at least one compound other than nanocellulose.
• the formulation in the present invention refers to any material to be mixed or complexed with nanocellulose.
• the formulation is any material and may be organic or inorganic, solid or liquid. The formulation may be appropriately selected depending on the intended use of the nanocellulose-containing composition.
• Nanocellulose is used in, for example, resins, fibers, rubber, foods, cosmetics, medical products, paints, inks, sheet films, molded products, inorganic materials, etc., but its use is not limited to these. Therefore, the nanocellulose-containing composition may be used in, for example, resins, fibers, rubbers, foods, cosmetics, medical products, paints, inks, sheet films, molded products, inorganic materials, etc., or manufactured in these applications. It can be an intermediate aspect on the way.
• the usage mode of the nanocellulose-containing composition for example, a resin containing the nanocellulose-containing composition, fibers, rubber, food, cosmetics, medical products, paints, inks, sheet films, molded products or inorganic materials, or Examples thereof include nanocellulose-containing compositions for forming resins, fibers, rubbers, foods, cosmetics, medical products, paints, inks, sheet films, molded products or inorganic materials.
• the formulation may be any component that can be included in these uses or in the form of intermediates of these uses.
• Nanocellulose may be used to improve functionality such as strength by containing it in resin or rubber, for example. Therefore, the production method of the present invention can be applied to, for example, the production of resin or rubber.
• the nanocellulose-containing composition is, for example, a composition for use in a resin or rubber
• the formulation may be the resin or rubber itself, or may be a raw material monomer before polymerization of these resins or rubber.
• the resin to which the production method of the present invention can be applied is not particularly limited, and examples thereof include a polymer of an ethylenically unsaturated monomer.
• a polymer of an ethylenically unsaturated monomer may be used, or an ethylenically unsaturated monomer may be used.
• Specific examples of the ethylenically unsaturated monomer include (meth) acrylic acid, alkyl (meth) acrylate, alkylene glycol (meth) acrylate, (meth) acrylonitrile, vinyl halide, maleic acidimide, phenylmaleimide, and (meth).
• alkyl (meth) acrylate examples include those having an alkyl moiety having 1 to 10 carbon atoms.
• the alkyl moiety may be linear, branched or cyclic, and may be unsubstituted or having a substituent.
• the ethylenically unsaturated monomer may have a functional group such as a carboxy group, a hydroxyl group, an epoxy group, an amino group, an amide group and a cyano group. Having these functional groups enhances the affinity for nanocellulose.
• the ratio of the ethylenically unsaturated monomer having these functional groups is 5 mol of the whole ethylenically unsaturated monomer. % Or less, more preferably 3 mol% or less, and even more preferably 1 mol% or less.
• the weight average molecular weight of the polymer of the ethylenically unsaturated monomer is not particularly limited. For example, it may be 50 to 3 million.
• the weight average molecular weight of the particle polymer is 5000 or more, the decrease in the strength of the resin is suppressed, and when the weight average molecular weight of the particles is 3 million or less, the particles tend to melt easily in the resin and a sufficient modification effect can be obtained. It is in.
• the weight average molecular weight (Mw) of the polymer of the ethylenically unsaturated monomer can be measured by the following method.
• the weight average molecular weight of the polymer of the ethylenically unsaturated monomer is measured using GPC (gel permeation chromatography, for example, HLC-8220, manufactured by Tosoh). Specifically, an appropriate solvent is added to a resin modifier containing nanocellulose and a polymer of an ethylene unsaturated monomer to dissolve the polymer. Then, the mixture is filtered using a 0.45 ⁇ m filter, and the obtained liquid is measured in terms of polystyrene.
• GPC gel permeation chromatography
• the nanocellulose in the present invention has a carboxy group. At least a part of the carbokil groups in the nanocellulose contained in the nanocellulose-containing composition may be modified. Therefore, the formulation may be a compound that modifies the carboxy group. Examples of the compound include amines and quaternary ammoniums.
• the nanocellulose-containing composition is a resin embodiment, the amine or quaternary ammonium salt compound reacts with the carboxy group on the surface of the nanocellulose to modify the nanocellulose, improve the hydrophobicity of the nanocellulose, and make the monomer or It is considered that the affinity for the resin is improved.
• the amine that modifies nanocellulose is not particularly limited and may be primary, secondary, or tertiary.
• the number of carbon atoms of the hydrocarbon group or aromatic group bonded to the nitrogen atom of the amine or quaternary ammonium salt compound (if two or more hydrocarbon groups or aromatic groups are bonded to the nitrogen atom, the total carbon thereof) The number) is not particularly limited and may be selected from 1 to 100 carbon atoms.
• an amine having a polyalkylene oxide structure such as an ethylene oxide / propylene oxide (EO / PO) copolymer may be used. From the viewpoint of imparting sufficient hydrophobicity to nanocellulose, the number of carbon atoms is preferably 3 or more, and more preferably 5 or more.
• the quaternary ammonium salt compound that modifies nanocellulose is not particularly limited.
• the quaternary ammonium salt compound includes a quaternary ammonium hydroxide such as tetrabutylammonium hydroxide, a quaternary ammonium chloride such as tetrabutylammonium chloride, and a quaternary ammonium bromide such as tetrabutylammonium bromide.
• a quaternary ammonium iodide such as tetrabutylammonium iodide can be considered.
• Amine or quaternary ammonium may be a compound, but the timing of addition in the production method of the present invention is not particularly limited.
• it may be contained in a mixture of cellulose oxide and at least one compound (that is, an embodiment in which the compound is an amine or a quaternary ammonium), or the mixture may be added after stirring. ..
• cellulose oxide may be stirred and amine or quaternary ammonium may be continuously added as at least one formulation.
• Nanocellulose may be used, for example, to disperse components that may be included in the applications described above.
• Inorganic particles can be preferably mentioned as such a component.
• the inorganic particles may be inorganic fine particles.
• Inorganic particles can be used in combination with nanocellulose, not limited to the above-mentioned uses.
• the inorganic particles that can be used in combination with nanocellulose are not particularly limited, and are, for example, simple metals such as copper, silver, nickel, palladium, carbon, silicon, aluminum, zinc, and platinum, and such. Examples thereof include metal compounds containing at least one kind of metal.
• the metal compounds include oxides, chlorides, halides (odorants, fluorides, etc.), inorganic acid salts (nitrates, sulfates, hydrochlorides, phosphates, phosphites, etc.), and organic acid salts (geicic acid). It may be a carboxylate such as a salt or an acetate, an oxycarboxylate such as a lactate or an malate).
• Examples of the metal compound include alumina, zirconia, titanium oxide, barium titanate, alumina nitride, silicon nitride, boron nitride, silicate glass, lead glass, inorganic glass, ruthenium oxide, yttrium oxide, cerium oxide and aluminum silicate.
• the carbon-containing compounds also include carbon black and carbon nanotubes.
• examples of the inorganic particles include copper oxide (CuO), iron oxide (Fe 2 O 3 ), cobalt oxide (Co 2 O 3 ), zinc oxide (ZnO), cerium oxide (CeO 2 ), and lithium oxide (Li 2 ).
• the size of the inorganic particles is not particularly limited, and the inorganic particles preferably include particles having a particle size of 1 nm or more and 1000 ⁇ m or less.
• the median diameter of the inorganic particles is preferably 0.01 ⁇ m or more and 100 ⁇ m or less, more preferably 0.05 ⁇ m or more and 50 ⁇ m or less, and further preferably 0.1 ⁇ m or more and 20 ⁇ m or less.
• the BET specific surface area of the inorganic particles is preferably 10 m 2 / g or more and 2000 m 2 / g or less, more preferably 10 m 2 / g or more and 1000 m 2 / g or less, and 50 m 2 / g or more and 1000 m 2 / g.
• the median diameter and the BET specific surface area are in the above ranges, the sedimentation of inorganic particles in the nanocellulose-containing composition tends to be further suppressed.
• the median diameter can be measured by a laser diffraction type particle size distribution measuring device.
• the BET specific surface area can be measured by a specific surface area pore distribution measuring device.
• the content of the compound in the production method of the present invention is not particularly limited and is arbitrary.
• the total amount of oxidized cellulose and nanocellulose contained in the nanocellulose-containing composition is not particularly limited, but is the total of the components constituting the nanocellulose-containing composition (however, excluding these when a solvent and a dispersion medium are contained). Based on the mass, for example, 0.1 to 90% by mass, 0.1 to 80% by mass, 0.1 to 70% by mass, 0.1 to 60% by mass, 0.1 to 50% by mass, 0.1.
• Nanocellulose in the present invention is derived from oxidized cellulose obtained by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof, and the oxidized cellulose is deflated and refined. Nanocellulose contains fine cellulose fibers.
• the average fiber length of nanocellulose in the present invention is not particularly limited, but is preferably 50 nm or more and 800 nm or less.
• the average fiber length is 50 nm or more, the quality of nanocellulose tends to be uniform.
• the lower limit of the average fiber length is more preferably 100 nm or more, still more preferably 150 nm or more.
• the average fiber length is 800 nm or less, the proportion of coarse cellulose fibers is suppressed, and the generation of nanocellulose precipitation tends to be suppressed.
• the upper limit of the average fiber length is more preferably 700 nm or less, further preferably 600 nm or less, still more preferably 500 nm or less, still more preferably 400 nm or less, still more preferably 300 nm or less. ..
• the average fiber length is more preferably 50 nm or more and 700 nm or less, further preferably 100 nm or more and 700 nm or less, still more preferably 100 nm or more and 600 nm or less, still more preferably 100 nm or more and 500 nm or less, and more. It is more preferably 100 nm or more and 400 nm or less, and further preferably 100 nm or more and 300 nm or less.
• the average fiber width of nanocellulose in the present invention is preferably 1 nm or more and 100 nm or less.
• the average fiber width is 1 nm or more, the quality of nanocellulose tends to be uniform.
• the lower limit of the average fiber width is more preferably 2 nm or more, still more preferably 3 nm or more.
• the average fiber width is 100 nm or less, the proportion of coarse nanocellulose is suppressed, and the generation of nanocellulose precipitation tends to be suppressed.
• the average fiber width is more preferably 50 nm or less, still more preferably 30 nm or less, still more preferably 20 nm or less, still more preferably 10 nm or less. From the viewpoint of further improving the quality of nanocellulose, the average fiber width is more preferably 2 nm or more and 50 nm or less, further preferably 3 nm or more and 30 nm or less, still more preferably 3 nm or more and 20 nm or less, still more preferably 3 nm or more and 10 nm or less. ..
• the aspect ratio (average fiber length / average fiber width) represented by the ratio of the average fiber width to the average fiber length is preferably 20 or more and 200 or less.
• the aspect ratio is more preferably 190 or less, still more preferably 180 or less.
• the aspect ratio is more preferably 30 or more, still more preferably 40 or more.
• the average fiber width and average fiber length are such that nanocellulose and water are mixed so that the concentration of nanocellulose is approximately 1 to 10 ppm, and a sufficiently diluted cellulose aqueous dispersion is naturally dried on a mica substrate.
• the range of the difference between the values depending on the conditions is preferably within the range of ⁇ 100 nm for the average fiber length.
• the range of the difference in values depending on the conditions is preferably within the range of ⁇ 10 nm for the average fiber width.
• the nanocellulose-containing composition When measuring various physical properties of nanocellulose in the present invention, the nanocellulose-containing composition may be used as a measurement sample, and nanocellulose after separation of nanocellulose and other components (combination) from the nanocellulose-containing composition. May be used as a measurement sample. Further, in the production method II, the sample at the time when the stirring of the oxidized cellulose is completed (before the addition of at least one compound) may be used as the measurement sample.
• the average fiber width, average fiber length, and aspect ratio can be suitably controlled by performing oxidation using hypochlorous acid or a salt thereof.
• the nanocellulose in the present invention can be characterized by an average fiber width, an average fiber length, or an aspect ratio, but in another embodiment, it has a predetermined zeta potential and light transmittance. May be.
• the nanocellulose in the present invention preferably has a zeta potential of ⁇ 30 mV or less.
• the zeta potential is -30 mV or less (that is, the absolute value is 30 mV or more)
• repulsion between microfibrils is sufficiently obtained, and nanocellulose having a high surface charge density is likely to be generated.
• the dispersion stability of nanocellulose is improved, and the viscosity stability and handleability of the slurry can be improved.
• the lower limit of the zeta potential is not particularly limited.
• the zeta potential when the zeta potential is -100 mV or more (that is, the absolute value is 100 mV or less), oxidative cleavage in the fiber direction with the progress of oxidation tends to be suppressed, so that nanocellulose having a uniform size can be obtained. Tend to be able to.
• the zeta potential for example, one or more of the reaction time, the reaction temperature, and the stirring condition of the oxidation should be set (for example, the reaction time should be lengthened) on the side where the oxidation is further promoted (that is, the side where the degree of oxidation is increased). Tends to be higher.
• the zeta potential can be suitably controlled by performing oxidation using hypochlorous acid or a salt thereof.
• the zeta potential of the nanocellulose in the present invention is more preferably ⁇ 35 mV or less, further preferably ⁇ 40 mV or less, still more preferably ⁇ 50 mV or less.
• the lower limit of the zeta potential is preferably ⁇ 90 mV or higher, more preferably ⁇ 85 mV or higher, still more preferably ⁇ 80 mV or higher, and even more preferably ⁇ 77 mV or higher.
• the range of the zeta potential can be appropriately combined with the above-mentioned lower limit and upper limit.
• the zeta potential is preferably ⁇ 90 mV or more and ⁇ 35 mV or less, more preferably ⁇ 85 mV or more and ⁇ 40 mV or less, and further preferably ⁇ 80 mV or more and ⁇ 50 mV or less.
• the zeta potential is measured under the conditions of pH 8.0 and 20 ° C. for a cellulose aqueous dispersion in which nanocellulose and water in the present invention are mixed and the concentration of nanocellulose is 0.1% by mass. It is the value that was set.
• the zeta potential can be measured in detail according to the following method. Pure water is added to the nanocellulose and diluted so that the concentration of the nanocellulose becomes about 0.1%. To the diluted nanocellulose aqueous dispersion, add 0.05 mol / L sodium hydroxide aqueous solution to adjust the pH to about 8.0, and use a zeta potential meter (ELSZ-1000) manufactured by Otsuka Electronics Co., Ltd., for example. The potential is measured at 20 ° C.
• the nanocellulose dispersion in which nanocellulose is dispersed in a dispersion medium in the present invention can exhibit high light transmittance with less light scattering of cellulose fibers.
• the nanocellulose in the present invention has a light transmittance of 95% or more in a mixed solution having a solid content concentration of 0.1% by mass by mixing with water.
• the light transmittance is more preferably 96% or more, further preferably 97% or more, still more preferably 99% or more.
• the light transmittance is a value measured by a spectrophotometer at a wavelength of 660 nm.
• the light transmittance can be measured, for example, by placing an aqueous dispersion of nanocellulose in a quartz cell having a thickness of 10 mm and using a spectrophotometer (JASCO V-550).
• Nanocellulose in the present invention is an aggregate of fibers in units of one.
• a carboxy group is introduced into the nanocellulose in the present invention, it suffices to contain at least one carboxylated nanocellulose (also referred to as carboxylated CNF), and the carboxylated nanocellulose is the main component.
• carboxylated CNF carboxylated nanocellulose
• the main component of the carboxylated CNF is that the ratio of the carboxylated CNF to the total amount of fine cellulose is more than 50% by mass, preferably more than 70% by mass, and more preferably more than 80% by mass. Refers to something.
• the upper limit of the above ratio is 100% by mass, but it may be 98% by mass or 95% by mass.
• nanocellulose in the nanocellulose-containing composition in the present invention can be one index of the physical properties of the nanocellulose-containing composition. That is, it can be determined from the fact that the composition has a function generated by nanocellulose, for example, the nanocellulose-containing composition has a slurry state and a viscosity. Specifically, when compared with the composition containing no nanocellulose, the composition obtained by the production method of the present invention was in the form of a slurry, thickening occurred, and the precipitate of the formulation. It can be judged that nanocellulose is contained because the above does not occur. Further, for example, when compared with a composition containing nanocellulose produced according to International Publication No. 2018/230354, the composition obtained by the production method of the present invention is in the form of a slurry equivalent to the above composition. It can be judged that it contains nanocellulose because it has a viscosity and viscosity.
• nanocellulose-containing composition obtained by the production method of the present invention contains nanocellulose is observed by observing the transmission phase difference with an optical microscope, and whether the used cellulose oxide remains coarse (the original cellulose oxide is maintained). Whether or not it can be determined.
• the nanocellulose-containing composition obtained by the production method of the present invention can be applied to various uses. Specifically, for example, it may be used as various materials (for example, resin, fiber, rubber, etc.), or may be used in various uses (for example, food, cosmetics, medical products, paints, inks, etc.). .. Further, the nanocellulose-containing composition can be formed into a film and used as various sheets or films.
• the field to which the nanocellulose-containing composition is applied is not particularly limited, and is used in the manufacture of products in various fields such as automobile parts, mechanical parts, electrical appliances, electronic devices, cosmetics, medical products, building materials, daily necessities, stationery and the like. can do.
• the flow time of the blank solution and the flow time of the cellulose solution were measured at 25 ° C. with a capillary viscometer. From the flow time (t0) of the blank solution, the flow time (t) of the cellulose solution, and the concentration of oxidized cellulose (c [g / ml]), the relative viscosity ( ⁇ r ) and the specific viscosity ( ⁇ sp ) are as shown in the following equations. The intrinsic viscosity ([ ⁇ ]) was sequentially obtained, and the degree of polymerization (DP) of cellulose oxide was calculated from the viscosity measurement formula.
• VP-1 powdered pulp manufactured by TDI
• the pH during the reaction was adjusted to 11 while keeping the temperature at 30 ° C. in the same constant temperature water bath while adding 48% by mass sodium hydroxide, and the mixture was stirred with a stirrer under the same conditions for 2 hours.
• the oxidized cellulose was recovered by repeating centrifugation (1000 G, 10 minutes), decantation, and addition of pure water in an amount corresponding to the removed liquid.
• the nitrogen component derived from the N-oxyl compound in the oxidized cellulose was measured as the amount of nitrogen using a trace total nitrogen analyzer (manufactured by Mitsubishi Chemical Analytech Co., Ltd., device name: TN-2100H), and increased from the raw material pulp. As a result of calculating the minute, it was 1.0 mass ppm or less. Further, using the obtained cellulose oxide, an aqueous dispersion of cellulose oxide having a concentration of cellulose oxide of 0.1% was prepared.
• the effective chlorine concentration in the sodium hypochlorite aqueous solution was measured by the following method. (Measurement of effective chlorine concentration in sodium hypochlorite aqueous solution) Precisely weigh 0.582 g of an aqueous solution of sodium hypochlorite pentahydrate crystals in pure water, add 50 mL of pure water, add 2 g of potassium iodide and 10 mL of acetic acid, immediately seal and place in the dark for 15 minutes. I left it.
• KC Flock W-100GK manufactured by Nippon Paper Industries, Ltd. was used as a raw material, and oxidized cellulose was obtained in the same manner as in Production Example 1 except that the reaction time was set to 4 hours.
• Oxidized cellulose was obtained in the same manner as in Production Example 4 except that the reaction time was set to 3 hours.
• Oxidized cellulose was obtained in the same manner as in Production Example 4 except that the reaction time was set to 1 hour.
• the fact that the cellulose oxides obtained in Production Examples 1 to 6 have a structure in which the hydroxyl groups at the 2- and 3-positions of the glucopyranose ring are oxidized and a carboxy group is introduced is a model molecule of the oxidized cellulose.
• the hydroxyl group at the 6th position was not oxidized. , It was judged that the hydroxyl group remained as a hydroxyl group in the oxidized cellulose.
• Table 1 shows the degree of polymerization, acid value (carboxy group amount), and light transmittance of the oxidized cellulose obtained in Production Examples 1 to 6.
• Example 1 Production of nanocellulose-containing composition
• Zinc oxide (10% by mass) is added to a mixture of zinc oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average particle size 20 nm) and cellulose oxide of Production Example 1. Pure water was added to adjust the concentration to 5% by mass of cellulose oxide to obtain a mixture.
• the obtained mixture was dispersed by stirring with a homomixer at 10,000 rpm for 10 minutes.
• CNF having an average fiber length of 196 nm and an average fiber width of 3.7 nm was confirmed. That is, it was confirmed that the nanocellulose-containing composition was obtained.
• particles (average height 10 nm to 30 nm) were also found instead of fibers, but they were presumed to be zinc oxide nanoparticles or their crushed matter or aggregates based on their shape. Excluded from CNF shape measurement.
• the dispersion-treated mixture was thickened, and no precipitation of zinc oxide was observed even when the mixture was allowed to stand at 23 ° C. for 2 days. It was confirmed that the thickening occurred and no precipitation was observed because the function of nanocellulose was expressed, and the nanocellulose-containing composition was obtained.
• Example 2 to 6 A nanocellulose-containing composition was obtained in the same manner as in Example 1 except that the oxidized cellulose of Production Examples 2 to 6 was used.
• Example 7 Production of nanocellulose-containing composition
• the oxidized cellulose of Production Example 1 was defibrated with a homomixer at 10,000 rpm for 10 minutes under the conditions of dispersion treatment, and an aqueous dispersion of nanocellulose (concentration: 1.0). Mass%) was obtained.
• the aqueous dispersion it was nanocellulose having an average fiber length of 165 nm and an average fiber width of 4.2 nm.
• the obtained CNF aqueous dispersion was appropriately concentrated by an evaporator, and then pure water was added so as to have zinc oxide (average particle diameter 20 nm) 10% by mass and nanocellulose 5% by mass, and the mixture was prepared.
• Got The mixture was thickened and no precipitation was seen.
• Example 8 to 12 A nanocellulose-containing composition was obtained in the same manner as in Example 7 except that the oxidized cellulose of Production Examples 2 to 6 was used.
• Example 1 A mixture was obtained in the same manner as in Example 1 except that the dispersion treatment by stirring with a homomixer was not performed. When this mixture was allowed to stand at 23 ° C. for 2 days, no thickening was observed and zinc oxide precipitates were observed. No thickening was observed and precipitation was observed, indicating that miniaturization did not proceed. That is, the nanocellulose-containing composition could not be obtained. When the transmission phase difference was observed with an optical microscope (manufactured by Nikon Corporation, product number: LV100ND), the cellulose oxide did not become fine and remained coarse. In addition, since the above mixture could not be analyzed by [method for measuring fiber length and fiber width], nanocellulose could not be observed, and the average fiber length and average fiber width were not calculated.
• 0.1 M sodium hydroxide was added and stirred to prepare an aqueous solution having a pH of 10.0.
• 129 g of an aqueous solution of sodium hypochlorite having an effective chlorine concentration of 13.2% by mass was added, and the pH during the reaction was adjusted to 10 while adding 0.1 M sodium hydroxide while keeping the temperature at 25 ° C. in the same constant temperature water bath.
• the pH was adjusted to 0.0 and stirring was performed for 2 hours.
• the oxidized cellulose was recovered by repeating centrifugation (1000 G, 10 minutes) and decantation.
• the present invention has industrial applicability in the field of using nanocellulose. Specifically, the present invention has industrial applicability in the fields of resins, fibers, rubbers, foods, cosmetics, medical products, paints, inks, sheets, films and the like.

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