WO2020226061A1

WO2020226061A1 - Emulsifier including carboxymethyl cellulose nanofibers and water-soluble polymer, and method for manufacturing emulsion using said emulsifier

Info

Publication number: WO2020226061A1
Application number: PCT/JP2020/017419
Authority: WO
Inventors: 井上　一彦; 裕亮多田; 苑加宮田; 伸治佐藤
Original assignee: 日本製紙株式会社
Priority date: 2019-05-08
Filing date: 2020-04-23
Publication date: 2020-11-12
Also published as: TW202108115A

Abstract

Provided is a novel application for carboxymethyl cellulose nanofibers. Carboxymethyl cellulose fibers and a water-soluble polymer in an amount that is 5-300 parts by mass per 100 parts by mass of said carboxymethyl cellulose fibers are mixed and dried to make an emulsifier. This emulsifier can be used to promote emulsification of an oleaginous medium and an aqueous medium.

Description

An emulsifier containing carboxymethylated cellulose nanofibers and a water-soluble polymer, and a method for producing an emulsion using the emulsifier.

The present invention relates to an emulsifier which is a dry solid of a mixture containing carboxymethylated cellulose nanofibers and a water-soluble polymer in a specific mixing ratio, and a method for producing an emulsion using the emulsifier.

Carboxymethylated cellulose is obtained by ether-bonding a carboxymethyl group to a part of the hydroxyl groups in the glucose residue of cellulose. 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, various industrial products, and the like. Since carboxymethylated cellulose is derived from natural cellulose, it is an environmentally friendly material that has mild biodegradability and can be incinerated and discarded, and its use is expected to expand in the future.

In carboxymethylated cellulose, when the amount of carboxymethyl groups increases (that is, when the degree of carboxymethyl substitution increases), the carboxymethylated cellulose becomes soluble in water. On the other hand, by adjusting the degree of carboxymethyl substitution in 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 (Patent Document 1).

International Publication No. 2014/088072

Carboxymethylated cellulose is used as an additive in various fields such as foods and drinks, cosmetics, and water-based paints because of its properties such as viscosity increase, water absorption, and water retention. Further, carboxymethylated cellulose nanofibers obtained by nanofibering carboxymethylated cellulose are also expected to be used as additives in various fields. An object of the present invention is to provide a new application of nanofibers of carboxymethylated cellulose.

As a result of diligent studies by the present inventors, water-soluble polymers were mixed with carboxymethylated cellulose nanofibers in a specific ratio and then dried to obtain a dry solid, which is an aqueous medium or an oil-based medium. When agitated and mixed with a stirring force (rotation speed 1000 to 8000 rpm) equivalent to that of a household mixer, the emulsification of the water-based medium and the oil-based medium is promoted and stable (that is, the water-based medium and the oil-based medium). It was found that an emulsion (which is difficult to separate from) can be formed. That is, it has been found that a dry solid containing nanofibers of carboxymethylated cellulose and a water-soluble polymer having a specific concentration can be used as an emulsifier. We have also found a method that can produce an emulsion with high emulsion stability using this emulsifier.

The present invention includes, but is not limited to, the following.
[1] An emulsifier containing a dry solid of a mixture of carboxymethylated cellulose nanofibers and a water-soluble polymer, wherein the amount of the water-soluble polymer is 5 when the carboxymethylated cellulose nanofibers are 100 parts by mass. The emulsifier, which is up to 300 parts by mass.
[2] The emulsifier according to [1], wherein the degree of carboxymethyl substitution per glucose unit of the carboxymethylated cellulose nanofiber is 0.01 to 0.50.
[3] The emulsifier according to [1] or [2], wherein the water-soluble polymer is carboxymethyl cellulose or a salt thereof.
[4] A food or drink containing the emulsifier according to any one of [1] to [3].
[5] A cosmetic product containing the emulsifier according to any one of [1] to [3].
[6] A coating material containing the emulsifier according to any one of [1] to [3].
[7] The steps of [1] to [3], which include a step of forming a mixture containing carboxymethylated cellulose nanofibers, a water-soluble polymer, and a solvent, and a step of drying the mixture using a drum-type drying device. The method for producing an emulsifier according to any one item.
[8] The production method according to [7], further comprising a step of adjusting the pH of the mixture to 9 to 11 before the drying step.
[9] Step 1, preparing a mixture of the emulsifier, the aqueous medium, and the oil-based medium by mixing the emulsifier according to any one of [1] to [3] with the aqueous medium and the oil-based medium. And the step 2 of preparing an emulsion in which the aqueous medium and the oil-based medium are emulsified by stirring the mixture of the emulsifier, the aqueous medium, and the oil-based medium.
A method for producing an emulsion containing.
[10] In the step 1, the emulsifier is first mixed with either an aqueous medium or an oil-based medium, and then the oil-based medium is added when the emulsifier is first mixed with the aqueous medium. The method for producing an emulsion according to [9], which comprises adding an aqueous medium when the emulsifier is first mixed with an oil-based medium.
[11] The method for producing an emulsion according to [10], which comprises first mixing the emulsifier with an oil-based medium and then adding an aqueous medium in the step 1.
[12] The method for producing an emulsion according to any one of claims 9 to 11, which comprises performing stirring at a rotation speed of 1000 to 8000 rpm in the step 2.
[13] The emulsifier is added in the step 1 so that the total amount of the carboxymethylated cellulose nanofibers and the water-soluble polymer in the emulsion obtained in the step 2 is 0.05 to 1.00% by mass. The method for producing an emulsion according to any one of [9] to [12], which comprises the above.

When the emulsifier of the present invention is mixed with an aqueous medium and an oil-based medium and stirred, it mixes well with the medium and can promote the formation of a stable emulsion. It can be said that the emulsifier of the present invention is suitable for use as an emulsifier in various fields requiring the formation of emulsions, for example, but not limited to these, in fields such as foods, cosmetics, and paints.

3 is a photograph showing the results when the emulsions produced in each of Examples 3 to 5 were allowed to stand at room temperature for 1 day. 6 is a photograph showing the results when the emulsions produced in each of Examples 6 to 8 were allowed to stand at room temperature for 1 day.

<Carboxymethylated cellulose nanofibers>
In the present invention, carboxymethylated cellulose nanofibers (hereinafter, "carboxymethylated" may be abbreviated as "CM" and cellulose nanofibers may be abbreviated as "CNF") are carboxymethylated cellulose (CM-modified cellulose). Is obtained by refining to a fiber width of nanometer level, and is usually a fine fiber having a fiber width of about 3 to several hundred nm, for example, about 4 to 500 nm. The aspect ratio is not limited, but is, for example, 100 or more. The average fiber diameter and average fiber length of CM-ized CNF are obtained from the results of observing 200 randomly selected fibers using an atomic force microscope (AFM) or a transmission electron microscope (TEM). It can be obtained by calculating the average value of the fiber lengths. Further, the aspect ratio can be calculated by dividing the average fiber length by the average fiber diameter. The CM-ized CNF can be obtained by applying a mechanical force to the CM-ized cellulose to make it finer (defibration).

CM-formed cellulose has a structure in which some of the hydroxyl groups in the glucose residues constituting the cellulose are ether-bonded to the carboxymethyl group. The CM-formed cellulose may take the form of a salt, and when the CM-modified cellulose is referred to in the present specification, the salt of the CM-modified cellulose is also included. Examples of the salt of CM-modified cellulose include metal salts such as sodium salt of CM-modified cellulose.

<Cellulose raw material>
Examples of the cellulose raw material for producing the CM-ized cellulose which is the raw material of the CM-ized CNF include vegetable materials (for example, wood, bamboo, hemp, jute, kenaf, farmland waste, cloth, pulp (coniferous unbleached craft). Pulp (NUKP), Coniferous Unbleached Craft Pulp (NBKP), Hardwood Unbleached Craft Pulp (LUKP), Hardwood Unbleached Craft Pulp (LBKP), Conifer Unbleached Sulfite Pulp (NUSP), Conifer Unbleached Sulfite Pulp (NBSP) Thermomechanical Pulp (TMP), recycled pulp, used paper, etc.)), animal materials (eg, squirrels), algae, microorganisms (eg, acetic acid bacteria (acetobacter)), and those originating from microbial products can be mentioned. , Any of them can be used. It is preferably a cellulose fiber derived from a plant or a microorganism, and more preferably a cellulose fiber derived from a plant.

<Commercialization of cellulose raw materials>
The CM-modified cellulose used as a raw material for CM-modified CNF may be obtained by carboxymethylating the above-mentioned cellulose raw material by a known method, or a commercially available product may be used. In any case, it is preferable that the degree of carboxymethyl group substitution per anhydrous glucose unit of cellulose is 0.01 to 0.50. The following method can be mentioned as an example of the method for producing such CM-formed cellulose.

A cellulose raw material and 3 to 20 times by mass of water and / or lower alcohol as a solvent, specifically, water, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, tertiary butanol, etc. Use alone or a mixed medium of two or more. As the mercerizing agent, 0.5 to 20 times mol of alkali metal hydroxide per anhydrous glucose residue of the cellulose raw material, specifically, sodium hydroxide and potassium hydroxide is used. The cellulose raw material, the solvent, and the mercerizing agent are mixed, and the mercerization treatment is carried out at a reaction temperature of 0 to 70 ° C., preferably 10 to 60 ° C., and a reaction time of 15 minutes to 8 hours, preferably 30 minutes to 7 hours. Then, 0.05 to 10.0 times the molar amount of the carboxymethylating agent is added per glucose residue, the reaction temperature is 30 to 90 ° C., preferably 40 to 80 ° C., and the reaction time is 30 minutes to 10 hours, preferably 1 hour. The etherification reaction is carried out for about 4 hours.

CM-modified cellulose, which is a raw material for CM-modified CNF, maintains at least a part of its fibrous shape even when dispersed in water, and is distinguished from carboxymethyl cellulose, which is a kind of water-soluble polymer described later. Will be done. When the aqueous dispersion of "carboxymethylated cellulose (CM-modified cellulose)" is observed with an electron microscope, a fibrous substance can be observed. On the other hand, when observing the aqueous dispersion of carboxymethyl cellulose, which is a kind of water-soluble polymer, no fibrous substance is observed. Further, in "carboxymethylated cellulose", the peak of cellulose type I crystal can be observed when measured by X-ray diffraction, but in the water-soluble polymer carboxymethyl cellulose, cellulose type I crystal is not observed.

<Defibration of CM-formed cellulose>
CM-ized CNF can be produced by defibrating CM-ized cellulose. The apparatus used for defibration is not particularly limited, but an apparatus such as a high-speed rotary type, a colloid mill type, a high pressure type, a roll mill type, and an ultrasonic type can be used. At the time of defibration, it is preferable to apply a strong shearing force to the dispersion of CM-formed cellulose. In particular, in order to efficiently defibrate, it is preferable to use a wet high-pressure or ultra-high pressure homogenizer capable of applying a pressure of 50 MPa or more to the dispersion and applying a strong shearing force. The pressure is more preferably 100 MPa or more, still more preferably 140 MPa or more. Further, 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. ..

<Degree of carboxymethyl substitution>
The CMized CNF preferably has a degree of carboxymethyl substitution per anhydrous glucose unit of cellulose of 0.01 to 0.50. When the degree of carboxymethyl substitution is less than 0.01, it becomes difficult to form a uniform emulsion due to precipitation or aggregation when an emulsifier is mixed with an aqueous medium or an oil medium. There is. Further, if the degree of carboxymethyl substitution exceeds 0.50, dissolution in an aqueous medium is likely to occur, the fiber morphology cannot be maintained, and the emulsification promoting effect and the emulsion stabilizing effect may be reduced. The lower limit of the carboxymethyl substitution degree is more preferably 0.10 or more, still more preferably 0.20 or more. The upper limit of the carboxymethyl substitution degree is more preferably 0.40 or less. The degree of carboxymethyl substitution of CM-modified CNF is adjusted by controlling the amount of carboxymethylating agent added, the amount of mercerizing agent, and the composition ratio of water and organic solvent to be reacted during the production of CM-modified cellulose as a raw material. be able to. The degree of carboxymethyl substitution of CM-modified cellulose and the degree of carboxymethyl substitution of CM-modified CNF obtained by defibrating it are usually the same.

In the present specification, the anhydrous glucose unit means individual anhydrous glucose (glucose residue) constituting cellulose. The degree of carboxymethyl substitution (also referred to as the degree of etherification) is the ratio of hydroxyl groups in glucose residues constituting cellulose that are substituted with carboxymethyl ether groups (carboxymethyl per glucose residue). The number of ether groups) is shown. 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 and place it in an Erlenmeyer flask with a 300 mL stopper. 100 mL of methanol nitrate (a solution of 1000 mL of methanol plus 100 mL of special grade concentrated nitric acid) is added and shaken for 3 hours to convert the salt of carboxymethylated cellulose (CMC) into H-CMC (hydrogen-type carboxymethylated cellulose). Weigh 1.5 to 2.0 g of the absolutely dry H-CMC and place it in an Erlenmeyer flask with a 300 mL 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. Using phenolphthalein as an indicator, excess NaOH is back titrated with 0.1 N-H ₂ SO ₄ , and the degree of carboxymethyl substitution (DS value) is calculated by the following formula.
A = [(100 x F'-0.1N-H ₂ SO ₄ (mL) x F) x 0.1] / (absolute dry mass (g) of H-CMC)
Carboxymethyl substitution degree = 0.162 × A / (1-0.058 × A)
F': 0.1N-H ₂ SO ₄ factor F: 0.1N-NaOH factor.

<Crystallinity of cellulose type I>
The crystallinity of cellulose type I in the CM-formed CNF is preferably 50% or more, more preferably 60% or more, from the viewpoint of promoting emulsification and stabilizing the emulsion. The crystallinity of cellulose type I in the CM-formed CNF can be controlled by the concentration of the mercerizing agent during the production of the CM-formed cellulose as a raw material, the temperature during the 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. For example, the amount of alkali (mercerizing agent) used is adjusted for modification. By adjusting the degree, the desired crystallinity can be maintained. The upper limit of the crystallinity of cellulose type I is not particularly limited. In reality, about 90% is considered to be the upper limit. The crystallinity of cellulose type I of CM-modified cellulose and the crystallinity of cellulose type I of CM-modified CNF obtained by defibrating it are usually the same.

The method for measuring the crystallinity of cellulose type I 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 is calculated by using a method such as Segal, and the diffraction intensity of the 002 surface of 2θ = 22.6 ° and 2θ = are based on the diffraction intensity of 2θ = 10 ° to 30 ° in the X-ray diffraction diagram. It is calculated by the following formula from the diffraction intensity of the amorphous portion of 18.5 °.
Xc = (I002c-Ia) / I002c × 100
Xc = Cellulose type I crystallinity (%)
I002c: 2θ = 22.6 °, diffraction intensity of 002 surface Ia: 2θ = 18.5 °, diffraction intensity of amorphous part.

<Water-soluble polymer>
In the present invention, examples of the water-soluble polymer include cellulose derivatives (carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, ethyl cellulose), xanthan gum, xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginate, purulan, and the like. Starch, shavings, debris, processed starch (cationized starch, phosphorylated starch, phosphoric acid crosslinked starch, phosphoric acid monoesterified phosphoric acid crosslinked starch, hydroxypropyl starch, hydroxypropylated phosphoric acid crosslinked starch, acetylated adipic acid crosslinked starch, acetylated Phosphoric cross-linked starch, acetylated oxidized starch, sodium octenyl succinate, acetate starch, oxidized starch), corn starch, Arabic gum, gellan gum, polydextrose, pectin, chitin, water-soluble chitin, chitosan, casein, albumin, soybean protein solution, Peptone, polyvinyl alcohol, polyacrylamide, sodium polyacrylic acid, polyvinylpyrrolidone, vinylacetate, polyamino acid, polylactic acid, polyapple acid, polyglycerin, latex, rosin-based sizing agent, petroleum resin-based sizing agent, urea resin, melamine resin , Epoxy resin, polyamide resin, polyamide polyamine resin, polyethyleneimine, polyamine, vegetable gum, polyethylene oxide, hydrophilic crosslinked polymer, polyacrylic acid salt, starch polyacrylic acid copolymer, tamarind gum, guar gum, and colloidal silica, Alternatively, a mixture of two or more of these can be mentioned. Among these, cellulose derivatives are preferable from the viewpoint of having good affinity with CMized CNF, and carboxymethyl cellulose and salts thereof are particularly preferable. It is considered that water-soluble polymers such as carboxymethyl cellulose and salts thereof penetrate between anion-modified cellulose nanofibers and increase the distance between CNFs to improve redispersibility. In addition, dextrin can also be preferably used as the above-mentioned water-soluble polymer. Since dextrin has low viscosity and high transparency, it does not easily affect the viscosity and transparency of CNF, and has an advantage that it can be mixed with CNF in an arbitrary ratio.

When carboxymethyl cellulose or a salt thereof is used as the water-soluble polymer, it is preferable to use carboxymethyl cellulose having a carboxymethyl group substitution degree of 0.55 to 1.60 per anhydrous glucose unit, and 0.55 to 1. 10 is more preferable, and 0.65 to 1.10 is even more preferable. Further, a molecule having a long molecule (high viscosity) is preferable because it has a high effect of widening the distance between CNFs, and the B-type viscosity at 25 ° C. and 30 rpm in a 1% by mass aqueous solution of carboxymethyl cellulose is 3 to 14000 mPa · s. Is preferable, 7 to 14000 mPa · s is more preferable, and 1000 to 8000 mPa · s is further preferable.

The mixing ratio of the water-soluble polymer and the CM-formed CNF is preferably a ratio such that the water-soluble polymer is 5 to 300 parts by mass when the CM-formed CNF (absolute dry solid content) is 100 parts by mass. Is 20 to 300 parts by mass. If it is less than 5 parts by mass, the emulsifier will not be sufficiently mixed with the medium, and if it exceeds 300 parts by mass, problems such as deterioration of emulsifying property will occur. The lower limit of the proportion of the water-soluble polymer is more preferably 25 parts by mass or more. The upper limit of the proportion of the water-soluble polymer is more preferably 200 parts by mass or less, and more preferably 60 parts by mass or less.

<Dry solids>
A mixture containing a CMized CNF, a water-soluble polymer, and a solvent is dried to produce a dry solid. In the present invention, the dry solid substance refers to a solid substance in an absolutely dry state (solvent amount 0% by mass) or in a wet state in which the solvent amount is 15% by mass or less. From the viewpoint of reducing the cost of transportation, the amount of the solvent is preferably 0 to 15% by mass, more preferably 0 to 10% by mass. The amount of solvent in the dry solid can be measured by the following method:
The dry solid is dried in an oven at 105 ° C. for 12 hours, and the amount of solvent of the dry solid is calculated from the mass before and after drying.
Solvent amount (mass%) of dry solids = {1- (mass after drying / mass before drying)} × 100.

The solvent that can be contained in the mixture before drying is not particularly limited, but water, a hydrophilic organic solvent, a hydrophobic organic solvent, or a mixed solvent thereof is preferable. Considering the dispersibility of CMized CNF, water or a mixed solvent of water and a hydrophilic organic solvent is preferable as the solvent. As a mixture of the solvent and CM-modified CNF, a dispersion of CM-modified CNF obtained by defibrating CM-modified cellulose may be used as it is, or the dispersion is concentrated by pretreatment such as drying or filtration. It may be used after being used as a dispersion. Further, a hydrophilic organic solvent is added to the dispersion of CM-modified cellulose or the dispersion of CM-modified CNF, or a part of the dispersion is replaced with a hydrophilic organic solvent to contain the CM-modified CNF and the hydrophilic organic solvent. It may be a mixture with a solvent. When the solvent is a mixed solvent of water and a hydrophilic organic solvent, the amount of the hydrophilic organic solvent is preferably 10% by mass or more, more preferably 20% by mass or more, and 25% by mass or more with respect to the mass of the mixed solvent. Is even more preferable. The upper limit of the amount is not limited, but is preferably 95% by mass or less, and more preferably 80% by mass or less.

The hydrophilic organic solvent means an organic solvent that dissolves in water. Examples include, but are not limited to, methanol, ethanol, 2-propanol, butanol, glycerin, acetone, methyl ethyl ketone, 1,4-dioxane, N-methyl-2-pyrrolidone, tetrahydrofuran, N, N-dimethylformamide, Examples include N, N-dimethylacetamide, dimethyl sulfoxide, acetonitrile, and combinations thereof. Among them, lower alcohols having 1 to 4 carbon atoms such as methanol, ethanol and 2-propanol are preferable, methanol and ethanol are more preferable, and ethanol is further preferable from the viewpoint of safety and availability.

The mixture of CMized CNF and solvent before drying further contains a water-soluble polymer. The water-soluble polymer may be added to the dispersion liquid of the cellulose raw material before carboxymethylation, may be added to the dispersion liquid of CM-modified cellulose before defibration, or CM-ized CNF after defibration. It may be added to the dispersion liquid of the above, or it may be added after replacing a part of the solvent of the dispersion liquid of the CM-ized CNF with a hydrophilic organic solvent.

The pH of the mixture containing the CMized CNF, the water-soluble polymer and the solvent is preferably adjusted to 9 to 11 before drying. When the pH is adjusted to 9 to 11 and then dried, the dispersibility in an aqueous medium or an oil medium becomes good. When adjusting the pH, an alkali such as sodium hydroxide may be used.

As a drying method, a known method can be used, and examples thereof include spray drying, pressing, air drying, hot air drying, and vacuum drying. The drying device is not particularly limited, but is a continuous tunnel drying device, a band drying device, a vertical drying device, a vertical turbo drying device, a multi-stage disk drying device, an aeration drying device, a rotary drying device, an air flow drying device, and a spray. Dryer drying device, spray drying device, cylindrical drying device, drum drying device, belt drying device, screw conveyor drying device, rotary drying device with heating tube, vibration transport drying device, batch type box drying device, aeration drying device, vacuum A box-type drying device, a stirring drying device, and the like can be used alone or in combination of two or more.

Among these, by using an apparatus that forms a thin film and performs drying, heat energy can be uniformly directly supplied to the object to be dried, and the drying process can be performed more efficiently and in a short time, which is energy efficient. It is preferable from the point of view. Further, an apparatus for forming a thin film and drying it is preferable because the dried product can be immediately recovered by a simple means such as scraping the thin film. Furthermore, it was also found that the redispersibility was further improved when the thin film was formed and then dried. Examples of the device for forming and drying a thin film include a drum type drying device and a belt type drying device for forming a thin film on a drum or a belt and drying the thin film. Of these, a drum-type drying device that facilitates continuous drying and recovery of dried products is preferable.

The drum type drying device continuously supplies a mixture of CMized CNF, a water-soluble polymer, and a solvent to the drum surface while rotating a heated drum to evaporate and concentrate the solvent, and at the same time, to the drum surface. This is an apparatus for producing a dry solid product by adhering CNF and a water-soluble polymer in a thin film form, drying the product, and scraping the dried product formed on the drum surface with a knife. The drum type drying device includes a double drum type device using two drums, a twin drum type device, and a single drum type device using one drum, but any of them may be used. Among these, a double drum type device capable of adjusting the film thickness of the thin film by adjusting the clearance between the drums is preferable.

The film thickness of the thin film to be dried is preferably 50 to 1000 μm, more preferably 100 to 300 μm. When it is 50 μm or more, it is easy to scrape after drying, and when it is 1000 μm or less, the effect of improving the dispersibility in an aqueous medium and an oil-based medium at the time of emulsification can be seen.

The drying temperature is not particularly limited. For example, it can be dried using a temperature of about 200 ° C. or lower. When drying is performed using a drum-type drying device or a belt-type drying device that forms and dries a thin film, the drying temperature refers to the temperature of the drum or belt surface.

Drying may be performed under normal pressure, vacuum or reduced pressure. Of these, drying under vacuum or reduced pressure has the advantages of lowering the boiling point of water, accelerating the evaporation rate, accelerating the drying of the object, and reducing the thermal effect on the sample. It is preferable because it can be used.

When drying under vacuum or reduced pressure (hereinafter, also referred to as "vacuum drying"), it is preferable to perform drying in the range of 0 to 50 kPa. Since the lower pressure gives the advantage that water can be evaporated at a lower temperature, it is preferably 50 kPa or less, more preferably 30 kPa or less, and further preferably 10 kPa or less.

At the time of drying, it is preferable to vacuum dry the mixture at a relatively low temperature such as 40 to 100 ° C. to obtain a dry solid. Since the production efficiency decreases when the drying temperature is low, the drying temperature is preferably 40 ° C. or higher, more preferably 45 ° C. or higher, and even more preferably 50 ° C. or higher. Further, if the drying temperature is high, the cellulose is colored or damaged, so the temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, more preferably 85 ° C. or lower, and 80 ° C. or lower. Is more preferable, and the temperature may be lower than 80 ° C.

The vacuum dryer is not particularly limited, but a vacuum box dryer, a vacuum drum dryer, a vacuum spray dryer, a vacuum belt dryer, etc. can be used alone or in combination of two or more. In the vacuum drum dryer, a heated drum is placed under vacuum or reduced pressure, and a mixture of CM-ized CNF, a water-soluble polymer, and a solvent is continuously supplied to the drum surface while rotating the drum. At the same time as evaporating and concentrating the solvent, CNF and a water-soluble polymer are attached to the drum surface in the form of a thin film and dried, and the dried product formed on the drum surface is scraped off with a knife to produce a dry solid product. It is a device.

The obtained dry solid material may be appropriately pulverized, classified, etc. to be in the form of powder, but may be in other forms. In the case of powder, the median diameter is preferably about 10.0 to 150.0 μm, more preferably 25.0 to 100.0 μm, still more preferably 35.0 to 70.0 μm. When the median diameter is 10.0 μm or more, problems such as powder flying are unlikely to occur, and when the median diameter is 150.0 μm or less, the volume is appropriate, so that the powder filling work is easy and preferable. The median diameter of the powder can be adjusted by adjusting the conditions for pulverization and classification.

The median diameter can be measured by the following procedure:
Using methanol as the dispersion medium, a sample is prepared so that the scattering intensity is 0.1 to 20%, and the sample is measured with a laser diffraction type particle size distribution measuring device (Mastersizer (registered trademark) 3000 manufactured by Malvern).

<Emulsifier>
The dry solid obtained above can promote the emulsification of the aqueous medium and the oil-based medium, and can be suitably used as an emulsifier. The emulsifier of the present invention contains a dry solid of a mixture of the above-mentioned CMized CNF and a water-soluble polymer. The emulsifier refers to an agent having an action of promoting emulsification between an aqueous medium and an oil-based medium and stabilizing emulsification. When an agent "promotes emulsification", it means that emulsification can be formed in the presence of the agent with less energy (less rotation speed of the mixer, less processing time, etc.) than in the absence of the agent. Also, the agent "stabilizes emulsification" means that the emulsion is retained in the presence of the agent for a longer period of time without separation into the aqueous medium and the oil-based medium than in the absence of the agent. To say that.

The emulsifier may contain a dye, an excipient, etc. as long as the effect of the present invention is not impaired, in addition to the above-mentioned dry solid.

The emulsifier of the present invention contains a dry solid of a mixture of CMized CNF and a water-soluble polymer. It is preferably in the form of a dry solid (eg, dried powder, etc.) as a whole. The emulsifier of the present invention mixes well with a mixture of an aqueous medium and an oil-based medium, and exhibits a high emulsification promoting effect and an emulsion stabilizing effect. The emulsifier of the present invention can be suitably used in various fields such as foods and drinks, cosmetics, paints, pharmaceuticals, feeds, and papermaking.

The emulsifier of the present invention can be used by adding it to foods and drinks. Foods and drinks include, but are not limited to, dressings, mayonnaise, whipped cream and the like.

The emulsifier of the present invention can be used by adding it to cosmetics. Cosmetics include, but are not limited to, facial cleansers, hair wash products, hair styling products, lotions, creams, nails, and the like.

The emulsifier of the present invention can be used by adding it to a paint. In addition, it can be used by adding it to an emulsified product, for example, an ointment in a pharmaceutical product, a feed (for example, milk replacer for cows, etc.).

<Manufacturing method of emulsion>
The emulsifier of the present invention is mixed with an aqueous medium and an oil-based medium to prepare a mixture of the emulsifier, the aqueous medium, and the oil-based medium (step 1), and the mixture is stirred (step 2). It can be emulsified with an oil-based medium to produce an emulsion. The aqueous medium refers to water and a water-soluble organic solvent that can be mixed with water in an arbitrary ratio, and examples thereof are as described above in the “Emulsifier” column. An oil-based medium is a substance that is liquid (including highly viscous but fluid) at room temperature, which does not mix (separate) when added to water. The oil-based medium differs depending on the type of emulsion, and examples thereof include, but are not limited to, edible oil, mineral oil (mineral oil), silicon oil, and squalane.

The water-based medium and the oil-based medium may be independently one or a mixture of a plurality of substances. The mixing ratio of the aqueous medium to be emulsified and the oil-based medium in the finally obtained emulsion is not particularly limited, and for example, the water-based medium: oil-based medium (mass ratio) is 1:99 to 99: 1. It may be a range.

The ratio of the CM-formed CNF and the water-soluble polymer in the finally obtained emulsion varies depending on the type of water-based medium or oil-based medium used, the mixing ratio of the water-based medium and the oil-based medium, and is not particularly limited, but is not particularly limited. It is preferable to add an emulsifier in step 1 so that the total amount of the CMized CNF and the water-soluble polymer is 0.01 to 5.00% by mass with respect to the mass of the emulsion. It is more preferably 0.02 to 3.00% by mass, more preferably 0.05 to 1.00% by mass, and even more preferably 0.10 to 0.50% by mass. It is considered that a stable emulsion (difficult to separate the water-based medium and the oil-based medium) can be formed by adding the emulsifier in such an amount according to the type of the water-based medium and the oil-based medium. .. When the solid content derived from the emulsifier is 0.50% by mass or less, there is an advantage that bubbles that may be generated by stirring can be suppressed from remaining in the emulsion.

When the emulsifier is mixed with the water-based medium and the oil-based medium (step 1), the emulsifier is not added as it is to the mixture of the oil-based medium and the water-based medium, but first added to either the oil-based medium or the water-based medium. It is preferable to allow the emulsifier to be blended with the oil-based medium or the aqueous medium, and then mixed with the other medium to which the emulsion has not been added, because the stability of the obtained emulsion is significantly improved. The reason why such an effect can be obtained is not clear, but first, it is speculated that the CM-ized CNF in the emulsifier swelled to some extent by mixing with one of the media, and it became easy to disperse. .. Further, as for the order of addition of the oil-based medium and the aqueous medium, it is better to first mix the oil-based medium with the emulsifier to prepare a mixture, and then mix the obtained mixture with the aqueous medium. This is preferable because the emulsion stabilizing effect is further enhanced as compared with the case where the mixture is first mixed with an aqueous medium and then mixed with an oil-based medium.

When the emulsifier is first added to either an aqueous medium or an oil-based medium, it is preferable to stir using a known mixing and stirring device after the addition. The stirring conditions at this time are not particularly limited, and for example, stirring may be performed at about 100 to 1000 rpm for about 1 to 10 minutes. After stirring, the other medium may be added.

After mixing the emulsifier, the aqueous medium, and the oil-based medium, the aqueous medium and the oil-based medium can be emulsified by stirring using a known mixing, stirring, emulsifying, or dispersing device (step). 2). Since the emulsifier of the present invention has good miscibility with an aqueous medium or an oil-based medium, an emulsion is formed with a stirring force equivalent to that of a household juicer mixer without using a special device such as a high-pressure homogenizer. be able to. Examples of such a mixer include a mixer having a rotation speed of 1000 to 15000 rpm, preferably 1000 to 12000 ppm, and more preferably 1000 to 8000 rpm. Using such a mixer, stirring may be performed for 1 minute or longer, preferably about 2 to 15 minutes, more preferably about 3 to 10 minutes.

The method for producing an emulsion of the present invention can be suitably used in various fields such as food and drink, cosmetics, paints, pharmaceuticals, feeds, and papermaking.

The method for producing an emulsion of the present invention can be used in the field of food and drink. For example, but not limited to these, it can be applied to the production of dressings, mayonnaise, whipped cream and the like.

The emulsion manufacturing method of the present invention can be used in the field of cosmetics. For example, but not limited to these, it can be applied to the production of facial cleansers, hair wash products, hair styling products, lotions, creams, nails and the like.

The emulsion manufacturing method of the present invention can be used in the field of paints. In addition, it can be applied to the production of emulsified products such as ointments in pharmaceutical products and feeds (for example, milk replacer for cows).

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

(Manufacturing of CM-ized CNF)
To a biaxial kneader whose rotation speed was adjusted to 100 rpm, 620 parts of isopropanol (IPA) and 10 parts of sodium hydroxide dissolved in 30 parts of water were added, and hardwood pulp (manufactured by Nippon Paper Industries, Ltd., LBKP) was added. 100 parts were charged by the dry mass when dried at 100 ° C. for 60 minutes. Mercerized cellulose was prepared by stirring and mixing at 30 ° C. for 90 minutes. Further, 15 parts of IPA and 12 parts of monochloroacetic acid were added with stirring, and after stirring for 30 minutes, the temperature was raised to 70 ° C. and a carboxymethylation reaction was carried out for 90 minutes.

After completion of the reaction, the mixture was neutralized with acetic acid until the pH reached 7, washed with hydrous methanol, deliquesed, dried and pulverized to obtain carboxymethylated cellulose having a carboxymethyl substitution degree of 0.18.

The carboxymethylated cellulose obtained in the above step was adjusted to 1.0% (w / v) with water and treated three times with an ultra-high pressure homogenizer (20 ° C., 150 MPa) to disperse the carboxymethylated cellulose nanofibers. Obtained liquid. The obtained fibers had an average fiber diameter of 5 nm and an aspect ratio of 150.

(Manufacturing of emulsifier)
Using the CM-modified CNF (carboxymethyl substitution degree 0.18, average fiber diameter 5 nm, aspect ratio 150) obtained above, an aqueous suspension having a solid content concentration of 0.7% by mass was prepared, and carboxymethyl cellulose was prepared therein. (Product name: Sunrose (registered trademark) F350HC-4, viscosity (1% by mass, 25 ° C., 30 rpm) about 3000 mPa · s, degree of carboxymethyl substitution about 0.92), 40% by mass with respect to CMized CNF. (That is, carboxymethyl cellulose is 40 parts by mass when the CM-formed CNF is 100 parts by mass), and the mixture is stirred with a TK homomixer (6000 rpm) for 5 minutes to obtain the CM-formed CNF and the water-soluble polymer. A mixture of (carboxymethyl cellulose) and solvent (water) was prepared. The pH of this mixture was about 7. An aqueous sodium hydroxide solution was added to this mixture to adjust the pH to 9. The solid content of the mixture at this time (including CMized CNF and carboxymethyl cellulose) was 1.4% by mass.

Next, the mixture (solid content 1.4% by mass) is applied to the drum surface of a drum dryer (manufactured by Katsuragi Kogyo Co., Ltd.) to form a thin film having a thickness of about 100 to 200 μm, and the drum surface temperature of the drum dryer is adjusted. It was dried at 140 ° C. and a drum rotation speed of 2 rpm to obtain a dry solid (embroidery) having a water content of 5% by mass.

(Example 1)
The dry solid (emulsifier) obtained above is added to a mixture of water: edible oil (canola oil) = 50:50 (mass ratio), and the solid content derived from the emulsifier with respect to the total of water, edible oil and emulsifier. It was added so that the ratio (including CM-formed CNF and carboxymethyl cellulose) was 0.50% by mass. When the emulsion was prepared by stirring for 5 minutes using a homomixer (6000 rpm) and allowed to stand at room temperature for 1 week to visually check the emulsified state, no separation between the aqueous medium and the oil-based medium was observed. It maintained emulsification. Some bubbles were seen in the emulsion.

(Example 2)
The procedure was carried out in the same manner as in Example 1 except that the emulsifier obtained above was added so that the proportion of the solid content derived from the emulsifier was 0.20% by mass. Even after standing at room temperature for 1 week, no separation between the aqueous medium and the oil-based medium was observed, and the emulsification was maintained. In addition, no bubbles were found in the emulsion, and the residual bubbles in the emulsion could be suppressed.

(Comparative Example 1)
Example 1 and Example 1 except that powdered cellulose KC Flock W-50GK (manufactured by Nippon Paper Industries, Inc., median diameter 45 μm, carboxymethyl substitution degree 0) was used instead of the dry solid containing CM-modified CNF and carboxymethyl cellulose. I did the same. The mixture was stirred with a homomixer, but the aqueous medium and the oil-based medium remained phase-separated, and a stable emulsion could not be obtained.

(Example 3)
The dry solid (emulsifier) obtained above is added to 50 parts by mass of edible oil (canola oil), and the mixture is stirred at 500 rpm for 5 minutes using a stirrer to mix the emulsifier and an oil-based medium (edible oil). Was prepared. The resulting mixture was mixed with 50 parts by weight of water and stirred with a homodisper (3000 rpm) for 5 minutes to prepare an emulsion. The total amount of CM-formed CNF and water-soluble polymer in the emulsion was 0.20% by mass. The obtained emulsion was allowed to stand at room temperature for 1 day. The results are shown in FIG.

(Example 4)
The dry solid (emulsifier) obtained above was added to 50 parts by mass of water and stirred at 500 rpm for 5 minutes using a stirrer to prepare a mixture of the emulsifier and an aqueous medium (water). The obtained mixture was mixed with 50 parts by mass of edible oil (canola oil) and stirred with a homodisper (3000 rpm) for 5 minutes to prepare an emulsion. The total amount of the CM-formed CNF and the water-soluble polymer in the emulsion was 0.20% by mass as in Example 1. The obtained emulsion was allowed to stand at room temperature for 1 day. The results are shown in FIG.

(Example 5)
The dry solid (emulsifier) obtained above is added to a mixture of 50 parts by mass of edible oil (canola oil) and 50 parts by mass of water, and the mixture is stirred with homodisper (3000 rpm) for 5 minutes, and then. It was allowed to stand at room temperature for 1 day. The total amount of CMized CNF and water-soluble polymer in the mixture of emulsifier, cooking oil and water was 0.20% by mass as in Example 1. The results are shown in FIG.

(Example 6)
The same procedure as in Example 3 was carried out except that the total amount of the CM-formed CNF and the water-soluble polymer in the emulsion was 0.10% by mass. The result after allowing the obtained emulsion to stand at room temperature for 1 day is shown in FIG.

(Example 7)
The same procedure as in Example 4 was carried out except that the total amount of the CM-formed CNF and the water-soluble polymer in the emulsion was 0.10% by mass. The result after allowing the obtained emulsion to stand at room temperature for 1 day is shown in FIG.

(Example 8)
The same procedure as in Example 5 was carried out except that the total amount of the CM-formed CNF and the water-soluble polymer in the mixture of the emulsifier, cooking oil and water was 0.10% by mass. The results after standing at room temperature for 1 day are shown in FIG.

Example 5 corresponds to the one in which the stirring speed at the time of emulsification in Example 1 was changed from 6000 rpm to 3000 rpm. From the results of FIG. 1, as compared with Example 5 in which the emulsifier (powder of dry solid) was added as it was to the mixture of the oil-based medium and the aqueous medium, the emulsifier was first mixed with the oil-based medium or the aqueous medium to prepare the mixture. It can be seen that in Examples 3 and 4 in which the obtained mixture was mixed with the other medium after formation, emulsification was maintained even after standing at room temperature for 1 day, showing high emulsification stability. .. Examples 6 to 8 correspond to Examples 3 to 5, respectively, and the amount of emulsifier (0.20% by mass) in Examples 3 to 5 is reduced to half (0.10% by mass). .. In Example 6 in which the emulsifier was first mixed with an oil-based medium to form a mixture and the resulting mixture was mixed with an aqueous medium, after standing at room temperature for 1 day, despite the small amount of emulsifier. It can be seen that emulsification was maintained and showed high emulsification stability. On the other hand, in Example 7 in which the emulsifier was first mixed with an aqueous medium to form a mixture and the obtained mixture was mixed with an oil-based medium, the amount of the emulsifier was reduced, and after standing for one day as compared with Example 4. It can be seen that the aggregation (creaming) of the emulsified particles progressed slightly, but the emulsification was generally maintained. Further, in Example 8 in which the emulsifier was added as it was to the mixture of the oil-based medium and the aqueous medium without first mixing with the oil-based medium or the aqueous medium, as in Example 5, after standing for one day, the emulsifier was added to the aqueous medium. It can be seen that the oil-based medium is separated. Based on the above, the emulsifier, which is a dry solid of a mixture of CM-formed CNF and a water-soluble polymer used in the present invention, is first mixed with an oil-based medium or an aqueous medium to form a mixture, and then this mixture is further mixed. By mixing with one of the media (Examples 3, 4, 6, 7), it exhibits higher emulsification stability as compared with the case of adding directly to the mixture of the oil-based medium and the aqueous medium (Examples 5, 8). It can be seen that an emulsion can be produced. Further, when the emulsifier is first mixed with the oil-based medium and then mixed with the aqueous medium (Example 4), when the emulsifier is first mixed with the aqueous medium and then mixed with the oil-based medium. In comparison (Example 7), it can be seen that high emulsification stability can be obtained.

Claims

An emulsifier containing a dry solid of a mixture of carboxymethylated cellulose nanofibers and a water-soluble polymer, and the amount of the water-soluble polymer is 5 to 300 parts by mass when the carboxymethylated cellulose nanofibers are 100 parts by mass. The above emulsifier, which is a part.
The emulsifier according to claim 1, wherein the degree of carboxymethyl substitution per glucose unit of the carboxymethylated cellulose nanofiber is 0.01 to 0.50.
The emulsifier according to claim 1 or 2, wherein the water-soluble polymer is carboxymethyl cellulose or a salt thereof.
A food or drink containing the emulsifier according to any one of claims 1 to 3.
Cosmetics containing the emulsifier according to any one of claims 1 to 3.
A paint containing the emulsifier according to any one of claims 1 to 3.
The item according to any one of claims 1 to 3, which comprises a step of forming a mixture containing carboxymethylated cellulose nanofibers, a water-soluble polymer, and a solvent, and a step of drying the mixture using a drum-type drying device. The method for producing an emulsifier according to the above.
The production method according to claim 7, further comprising a step of adjusting the pH of the mixture to 9 to 11 before the drying step.
Step 1 of mixing the emulsifier according to any one of claims 1 to 3 with an aqueous medium and an oil-based medium to prepare a mixture of the emulsifier, the aqueous medium, and the oil-based medium, and the emulsifier and the aqueous medium. Step 2, in which the mixture of the medium and the oil-based medium is stirred to prepare an emulsion in which the aqueous medium and the oil-based medium are emulsified.
A method for producing an emulsion containing.
In step 1, the emulsifier is first mixed with either an aqueous medium or an oil medium, then the oil medium is added when the emulsifier is first mixed with the aqueous medium, while the emulsifier is added. The method for producing an emulsion according to claim 9, which comprises adding an aqueous medium when first mixed with an oil-based medium.
The method for producing an emulsion according to claim 10, wherein in the step 1, the emulsifier is first mixed with an oil-based medium, and then an aqueous medium is added.
The method for producing an emulsion according to any one of claims 9 to 11, which comprises performing stirring at a rotation speed of 1000 to 8000 rpm in the step 2.
The emulsifier is added in the step 1 so that the total amount of the carboxymethylated cellulose nanofibers and the water-soluble polymer in the emulsion obtained in the step 2 is 0.05 to 1.00% by mass. The method for producing an emulsion according to any one of claims 9 to 12, which comprises.