JP6791725B2 - Method for producing cellulose derivative - Google Patents

Description

The present invention relates to a method for producing a cellulose derivative.

Cellulose derivatives such as cationized hydroxyalkyl cellulose are used as compounding ingredients, dispersants, modifiers, flocculants, etc. of hair cosmetic compositions such as shampoos, rinses, treatments, and conditioners, and have a wide range of uses. ..

As a method for producing cationized hydroxyalkyl cellulose, Patent Document 1 describes a cation having excellent water solubility in which low crystallinity powdered cellulose is reacted with a specific cationizing agent and propylene oxide in the presence of a predetermined amount of water and a catalyst. A method for producing hydroxypropyl cellulose is disclosed.
Patent Document 2 describes hydroxyalkyl cellulose, which is reacted by dividing and adding a predetermined amount of a basic compound and an alkylene oxide to cellulose for the purpose of obtaining hydroxyalkyl cellulose having excellent water solubility while maintaining a high reaction selectivity. A production method and a method for producing cationized hydroxyalkyl cellulose by reacting the hydroxyalkyl cellulose with a cationizing agent are disclosed.
Patent Document 3 describes, for example, hydroxypropyl cellulose and the like, which comprises a step of reacting a powdery polysaccharide with a compound having a reactive functional group in the presence of a basic catalyst and then sieving with a predetermined classifier. A method for producing a powdered polysaccharide derivative is disclosed.
Further, Patent Document 4 describes that one or more powdered raw material cellulose selected from cellulose and a cellulose derivative and a predetermined amount of a reactant having a cationic group are mixed in a predetermined stirring condition in the presence of a basic catalyst. Disclosed is a method for producing a powdered cationized cellulose derivative capable of uniformly reacting a cationic group with a high reaction rate by spraying and supplying the reactant to react.

Japanese Unexamined Patent Publication No. 2011-94033 Japanese Unexamined Patent Publication No. 2014-132065 Japanese Unexamined Patent Publication No. 2014-205798 JP 2015-52104

Cellulose derivatives may be blended in various hair cosmetic compositions and the like in the form of an aqueous solution. However, when the method for treating the cellulose-containing raw material used as the raw material for the cellulose derivative and the method for derivatizing the cellulose-containing raw material are the same, the obtained cellulose derivative is dissolved in water to prepare an aqueous solution. In some cases, the transparency of the aqueous solution varied. If there is such a variation, it also affects the production stability of the product containing the aqueous solution of the cellulose derivative.

An object of the present invention is to provide a method for producing a cellulose derivative, which can stably obtain a highly transparent aqueous solution when dissolved in water.

The present invention relates to a method for producing a cellulose derivative, which comprises the following steps (I) and (II).
Step (I): The cellulose-containing raw material is pulverized to obtain powdered cellulose having a water content of less than 2.5% by mass and a crystallization index of −3.5% or less calculated by the following formula (1). Process Crystallization index (%) = [(I _22.6 −I _18.5 ) / I _22.6 ] × 100 (1)
[In the formula, I _22.6 shows the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) of the cellulose I type crystal in X-ray diffraction, and I _18.5 is the amorphous part (diffraction angle 2θ =). It shows a diffraction intensity of 18.5 °). ]
Step (II): The powdered cellulose obtained in the step (I) and the reactant are equivalent to 0.5 mol equivalent or more with respect to 1 mol of the anhydroglucose unit of the cellulose constituting the main chain of the powdered cellulose. A step of reacting in the presence of a basic compound having 0 molar equivalents or less to obtain a cellulose derivative.

When the cellulose derivative such as cationized hydroxyalkyl cellulose obtained by the production method of the present invention is dissolved in water, a highly transparent aqueous solution can be obtained. The cellulose derivative and its aqueous solution can be blended with various hair cosmetic compositions such as shampoos, conditioners, treatments, and conditioners to supply products with stable quality.

[Method for producing cellulose derivatives]
The method for producing a cellulose derivative of the present invention (hereinafter, also referred to as "the method for producing the present invention") has the following steps (I) and (II).
Step (I): The cellulose-containing raw material is pulverized to obtain powdered cellulose having a water content of less than 2.5% by mass and a crystallization index of −3.5% or less calculated by the following formula (1). Process Crystallization index (%) = [(I _22.6 −I _18.5 ) / I _22.6 ] × 100 (1)
[In the formula, I _22.6 shows the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) of the cellulose I type crystal in X-ray diffraction, and I _18.5 is the amorphous part (diffraction angle 2θ =). It shows a diffraction intensity of 18.5 °). ]
Step (II): The powdered cellulose obtained in the step (I) and the reactant are equivalent to 0.5 mol equivalent or more with respect to 1 mol of the anhydroglucose unit of the cellulose constituting the main chain of the powdered cellulose. A step of reacting in the presence of a basic compound having 0 molar equivalents or less to obtain a cellulose derivative.

In the present invention, the cellulose crystallization index refers to the cellulose crystallization index derived from the type I crystal structure of cellulose, and is obtained from the result of X-ray crystal diffraction measurement by the above calculation formula (1). The lower the value of the crystallization index, the lower the crystallinity of cellulose.

In the present invention, the cellulose derivative refers to a compound in which at least one of the hydroxyl groups of cellulose is substituted with a substituent, and examples thereof include cellulose ether. Examples of the cellulose ether include hydroxyalkyl cellulose such as hydroxyethyl cellulose and hydroxypropyl cellulose, glycerolated cellulose, cationized cellulose, and cationized hydroxyalkyl cellulose.
In the present invention, the cellulose derivative is preferably one or more selected from the group consisting of hydroxyalkyl cellulose, cationized cellulose, and cationized hydroxyalkyl cellulose, and is water-soluble and has performance when blended in a hair cosmetic composition. From this point of view, it is more preferable that the cellulose derivative is cationized hydroxyalkyl cellulose.
Further, in the present invention, the reactant means a compound capable of reacting with a primary or secondary hydroxyl group of cellulose to introduce a substituent, and the details will be described later.

In the production method of the present invention, in the step (I), the cellulose-containing raw material is pulverized, the water content is less than 2.5% by mass, and the crystallization index obtained by the above formula (1) is −3.5. It is characterized by obtaining powdered cellulose of% or less.
The water content here means the water content in the cellulose-containing raw material. If the powdered cellulose obtained in the step (I) does not satisfy both the predetermined water content and the value of the crystallization index, the transparency of the finally obtained aqueous solution of the cellulose derivative is lowered.
Further, in the production method of the present invention, in step (II), the powdered cellulose and the reactant are combined with 1 mol of anhydroglucose unit (hereinafter, also referred to as “AGU”) of the cellulose constituting the main chain of the powdered cellulose. It is characterized in that the reaction is carried out in the presence of a basic compound having an equivalent of 0.5 molar equivalent or more and 3.0 molar equivalent or less. This is because if the amount of the basic compound used in the step (II) is less than 0.5 mol equivalent with respect to 1 mol of AGU of powdered cellulose, the transparency of the finally obtained aqueous solution of the cellulose derivative is lowered. Further, if the equivalent is 3.0 molar equivalents or less, side reactions such as a hydration reaction of a reactant such as a hydroxyalkylating agent described later are unlikely to proceed, which is advantageous from the viewpoint of economy.
In the present specification, the molar equivalent of a basic compound means a value obtained by multiplying the molar amount of a basic compound by the valence of a base. For example, 1 mol of a divalent basic compound such as calcium hydroxide is 2 mol. Equivalent to the equivalent.

The reason why the above effect is obtained in the present invention is not clear, but it is considered as follows.
The lower the crystallization index of cellulose, the more relaxed the crystal structure is shown, and the more uniformly the addition of the reactant is likely to proceed. Further, since the water content of the cellulose-containing raw material at the time of pulverization affects the rate of decrease of the cellulose crystallization index, the crystallization index can be efficiently and stably set to a predetermined level by controlling the water content to a certain level or less. Can be reduced to. As a result, when the powdered cellulose obtained in the step (I) with both the water content and the crystallization index reduced was used, the addition of the reactant proceeded uniformly in the step (II), and the water-soluble cellulose derivative obtained was obtained. It is considered that the property and the transparency of the aqueous solution are improved.

In the production method of the present invention, if powdered cellulose satisfying both the predetermined water content and the value of the crystallization index is obtained in the step (I), the powdered cellulose is absorbed before being subjected to the step (II). The water content and the crystallization index may be changed accordingly. That is, the powdered cellulose used in the step (II) may be in the state of powdered cellulose having a predetermined water content and a crystallization index in the step (I).
Hereinafter, the present invention will be described in detail.

<Step (I)>
In the step (I), the cellulose-containing raw material is pulverized to obtain powdered cellulose having a water content of less than 2.5% by mass and a crystallization index of −3.5% or less obtained by the above formula (1). obtain.
By making cellulose into a low crystallinity powder, the reactivity with the reactant used in step (II) can be enhanced. Further, when the powdered cellulose obtained in the step (I) satisfies both the water content and the crystallization index value, the finally obtained aqueous solution of the cellulose derivative has high transparency.

(Cellulose-containing raw material)
The cellulose-containing raw materials used in the present invention include chemically pure cellulose, various wood chips, pruned branches of various trees, thinned wood, branch wood, construction waste, factory waste, and other wood; manufactured from wood. Pulps such as wood pulp and cotton linter pulp obtained from fibers around cotton seeds; papers such as newspapers, cardboards, magazines, and fine papers; plant stems and leaves such as rice straw and corn stalks; paddy husks , Palm shells, plant shells such as coconut shells, and various other cellulose-containing raw materials can be used. Among these, pulps are preferable.

As a method for obtaining powdered cellulose having a water content of less than 2.5% by mass and a crystallization index of -3.5% or less, for example, a cellulose-containing raw material is cut and dried as necessary, and then the water content is 2. Examples thereof include a method of pulverizing with a pulverizer under a condition of less than 5% by mass. In particular, as will be described later, it is preferable to adopt a method in which the pulverization treatment is performed in multiple stages, that is, a method in which the cellulose-containing raw material is roughly pulverized and then the particle size reduction treatment is performed. In the pulverization treatment, the cellulose-containing raw material can be pulverized and the crystallization index can be reduced, so that the reactivity with the reactant used in the step (II) is further improved. Furthermore, the transparency of the aqueous solution of the obtained cellulose derivative can be improved. Hereinafter, the cutting treatment, the drying treatment, and the crushing treatment will be described.

(Cut processing)
Depending on the type and shape of the cellulose-containing raw material, it is preferable to perform a cutting treatment as a pretreatment. The method for cutting the cellulose-containing raw material can be appropriately selected depending on the type and shape of the cellulose-containing raw material, and examples thereof include a method using one or more cutting machines selected from a shredder, a slitter cutter and a rotary cutter. ..
When a sheet-shaped cellulose-containing raw material is used, it is preferable to use a shredder or a slitter cutter as a cutting machine, and it is more preferable to use a slitter cutter from the viewpoint of improving productivity.
A slitter cutter is a cutting machine that cuts vertically along the longitudinal direction of a sheet with a roll cutter into elongated strips, and then cuts shortly in the width direction of the sheet with a fixed blade and a rotary blade. By using a slitter cutter, the shape of the raw material cellulose can be diced. As the slitter cutter, a cutting machine (super cutter) manufactured by Ogino Seiki Seisakusho Co., Ltd., a sheet pelletizer manufactured by Horai Co., Ltd., or the like can be preferably used.

When cutting wood such as thinned wood, pruned branch wood, construction waste wood, or cellulose-containing raw materials other than sheet-like materials, it is preferable to use a rotary cutter. The rotary cutter is composed of a rotary blade and a screen, and by using the rotary cutter, it is possible to easily obtain a cellulose-containing raw material cut to a size equal to or smaller than the opening of the screen by the rotary blade. If necessary, a fixed blade may be provided, and cutting may be performed by a rotary blade and a fixed blade.
When using a rotary cutter, the size of the cut product obtained can be controlled by changing the opening of the screen.

The size of the cellulose-containing raw material obtained after the cutting treatment is preferably 1 mm square or more, more preferably 1.5 mm square or more, from the viewpoint of improving productivity, and reduces the load required for crushing in the subsequent crushing treatment. From the viewpoint of efficiently and easily performing the drying treatment described later, the size is preferably 70 mm square or less, more preferably 50 mm square or less.

(Drying process)
In general, commercially available pulps, papers used as biomass resources, woods, plant stems / leaves, plant shells and other cellulose-containing raw materials usually contain about 5 to 30% by mass of water. Therefore, usually, the water content of the cellulose-containing raw material is adjusted to less than 2.5% by mass by performing a drying treatment of the cellulose-containing raw material, preferably the cellulose-containing raw material obtained after the cutting treatment.

The temperature in the drying treatment is preferably 50 ° C. or higher, more preferably 100 ° C. or higher, still more preferably 130 ° C. or higher from the viewpoint of efficient drying, and preferably 250 ° C. or lower, more preferably from the viewpoint of quality assurance. Is 200 ° C. or lower, more preferably 170 ° C. or lower. From the viewpoint of reducing the amount of water, the drying treatment time is preferably 0.01 hours or more, more preferably 0.1 hours or more, still more preferably 0.5 hours or more. Further, from the viewpoint of efficient drying, it is preferably 2 hours or less, more preferably 1.5 hours or less.
The drying treatment may be carried out under reduced pressure if necessary, and the absolute pressure is preferably 1 kPa or more, more preferably 50 kPa or more, still more preferably 100 kPa or more, and preferably 100 kPa or more, from the viewpoint of efficient drying. It is 120 kPa or less, more preferably 105 kPa or less.
As the drying method, a known drying means may be appropriately selected. For example, the method described in "Introduction to Powder Engineering" (edited by Japan Powder Industry Technology Association, published in 1995 by Powder Engineering Information Center) is described on page 176. Can be mentioned. Examples of the drying means include a hot air heat receiving drying method, a conduction heat receiving drying method, a dehumidifying air drying method, a cold air drying method, a microwave drying method, an infrared drying method, a sun drying method, a vacuum drying method, and a freeze drying method. ..
These drying methods may be used alone or in combination of two or more, and the conduction heat receiving drying method is preferable from the viewpoint of efficient drying. The drying treatment can be either batch treatment or continuous treatment, but continuous treatment is desirable from the viewpoint of improving productivity.

As the continuous dryer, a conduction heat receiving type horizontal stirring dryer is preferable from the viewpoint of heat transfer efficiency. Further, a biaxial horizontal stirring dryer is preferable from the viewpoint that fine powder is less likely to be generated and the stability of continuous discharge is improved. As the 2-axis horizontal stirring dryer, a 2-axis paddle dryer manufactured by Nara Machinery Co., Ltd. can be preferably used.

The lower limit of the water content of the cellulose-containing raw material to be subjected to the pulverization treatment after the drying treatment is 0% by mass with respect to the cellulose-containing raw material, but from the viewpoint of improving productivity, the water content is preferably 0. It is 1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more. Further, the water content is preferably 2.5% by mass from the viewpoint of efficiently pulverizing and lowering the crystallization of the cellulose-containing raw material in the pulverization treatment and improving the transparency of the aqueous solution of the finally obtained cellulose derivative. It is less than, more preferably 2.3% by mass or less, still more preferably 2.1% by mass or less, still more preferably 2.0% by mass or less, still more preferably 1.8% by mass or less.
Specifically, the water content can be measured by the method described in Examples.

(Crushing)
From the viewpoint of obtaining powdered cellulose having a water content of less than 2.5% by mass, the pulverization treatment is preferably carried out under the condition that the water content in the cellulose-containing raw material is less than 2.5% by mass. When the water content of the powdered cellulose obtained in the step (I) is 2.5% by mass or more, the transparency of the aqueous solution of the cellulose derivative finally obtained is lowered. In addition, the pulverization efficiency and low crystallization efficiency in the pulverization treatment are also lowered. The preferable range of the water content is as described above.

From the viewpoint of efficiently powdering and low-crystallizing the cellulose-containing raw material and improving the transparency of the finally obtained aqueous solution of the cellulose derivative, it is preferable to carry out the pulverization treatment in multiple stages. When the pulverization treatment is performed in a plurality of stages, a method in which the cellulose-containing raw material that has been cut and dried is roughly pulverized and then subjected to a particle size reduction treatment is preferable.
The crusher used in the pulverization treatment is not particularly limited as long as it is an apparatus capable of pulverizing the cellulose-containing raw material and reducing the crystallization index to a predetermined value or less. And it is more preferable to use a high-speed rotary pulverizer. More specifically, it is more preferable to use a vibrating rod mill in the coarse pulverization treatment and a high-speed rotary fine pulverizer in the particle size reduction treatment.

[Coarse crushing process]
In the coarse pulverization treatment, the cellulose-containing raw material that has been cut and dried as necessary is roughly pulverized to be powdered and low-crystallized. In the coarse pulverization treatment, a large amount of treatment can be performed in a short time, so that low crystallized powdered cellulose can be efficiently obtained. Hereinafter, the cellulose obtained after the coarse pulverization treatment is also referred to as "crude pulverized cellulose".
Specific examples of the crusher used for the coarse crushing process include a high-pressure compression roll mill, a roll mill such as a roll rotation mill, a ring roller mill, a roller race mill, a vertical roller mill such as a ball race mill, a rolling ball mill, and a vibrating ball mill. , Vibration rod mill, Vibration tube mill, Planetary ball mill, Centrifugal fluidization mill, etc., Container-driven medium mill, High-speed centrifugal roller mill, Ong mill, etc. , Cutter mill and the like. These crushers can be used alone or in combination of two or more.
Among these, a container-driven medium mill is preferable, a vibration mill such as a vibration ball mill, a vibration rod mill, or a vibration tube mill is more preferable, and a vibration rod mill is preferable from the viewpoint of improving the pulverization efficiency and low crystallization efficiency of the cellulose-containing raw material. More preferred. The crushing method may be either a batch type or a continuous type.
The material of the crusher and the material of the medium used for the crushing treatment are not particularly limited, and examples thereof include iron, stainless steel, alumina, zirconia, silicon carbide, silicon carbide, glass, etc., but from the viewpoint of crushing efficiency of the cellulose-containing raw material. Therefore, iron, stainless steel, zirconia, silicon carbide, and silicon nitride are preferable, and iron or stainless steel is more preferable from the viewpoint of industrial use.

From the viewpoint of improving the crushing efficiency and low crystallization efficiency of the cellulose-containing raw material, when the crusher used for the coarse crushing treatment is a vibration mill and the medium is a rod (that is, when the crusher is a vibration rod mill), The outer diameter of the rod is preferably 10 mm or more, more preferably 20 mm or more, further preferably 25 mm or more, preferably 60 mm or less, more preferably 50 mm or less, still more preferably 45 mm or less.
The suitable range of the rod filling rate differs depending on the model of the vibration mill, but from the viewpoint of improving the crushing efficiency and productivity of the cellulose-containing raw material, it is preferably 10% by volume or more with respect to the volume of the crushing container. It is preferably 15% by volume or more, more preferably 50% by volume or more, still more preferably 60% by volume or more, and preferably 97% by volume or less, more preferably 90% by volume or less.
When the filling rate is within this range, the contact frequency between the cellulose-containing raw material and the rod can be improved, and the pulverization efficiency can be improved without hindering the movement of the medium. Here, the filling rate means the volume of the rod with respect to the volume of the stirring portion of the vibrating mill.

The processing time in the coarse pulverization process cannot be unconditionally determined depending on the type of vibration mill, rod material, shape, size and filling rate, filling rate of cellulose-containing raw material, etc., but in the case of batch processing, the particle size of cellulose is reduced. From the viewpoint of productivity and productivity, the lower limit is preferably 1 minute or longer, more preferably 2 minutes or longer, further preferably 3 minutes or longer, still more preferably 4 minutes or longer, and the upper limit thereof is preferably 120 minutes or longer. Minutes or less, more preferably 60 minutes or less, still more preferably 45 minutes or less, still more preferably 30 minutes or less.
Even when continuous treatment is performed, the treatment speed in the coarse pulverization treatment varies depending on the type and size of the vibration mill, the filling rate of the rod, etc., but the supply speed of the cellulose-containing raw material is preferably 5 kg / h from the viewpoint of productivity. As mentioned above, it is more preferably 10 kg / h or more, and preferably 100 kg / h or less, more preferably 80 kg / h or less from the viewpoint of advancing the particle size reduction and crystallization.

The treatment temperature in the rough pulverization treatment is not particularly limited, but is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, still more preferably 15 ° C. from the viewpoint of preventing coloration of cellulose and reducing the molecular weight due to heat and from the viewpoint of cost. The above is preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 150 ° C. or lower.

By the above treatment method, coarsely pulverized cellulose can be efficiently obtained from the cellulose-containing raw material. In the coarse pulverization treatment, reaggregation of the coarsely pulverized cellulose can be suppressed, and the pulverized product can be processed by a dry method without sticking to the inside of the pulverizer.
Further, since low crystallization of cellulose is mainly performed in the coarse pulverization treatment, the crystallization index of the coarsely pulverized cellulose obtained by the coarse pulverization treatment is preferably −3.5% or less.

[Small particle size treatment]
In the particle size reduction treatment, the coarsely pulverized cellulose obtained by the coarse pulverization treatment is further pulverized to reduce the particle size. By performing the particle size reduction treatment following the coarse pulverization treatment, powdered cellulose having a smaller volume medium particle size (D50) can be efficiently obtained.
As the pulverizer used for the particle size reduction treatment, a high-speed rotary pulverizer is preferable. The high-speed rotary pulverizer is a device that rotates a hammer, a blade, a pin, or the like at high speed to pulverize coarsely pulverized cellulose loaded in a pulverization cylinder by impact or shearing.

As a high-speed rotary pulverizer used for the particle size reduction treatment, the high-speed rotary mill and classification described on page 843 of "Revised Sixth Edition Chemical Engineering Handbook" (edited by the Chemical Engineering Society of Japan, published by Maruzen Co., Ltd., 1999). Examples include those classified as built-in high-speed rotary mills. Among these high-speed rotary mills and high-speed rotary mills with a built-in classifier, any one selected from the group consisting of a hammer mill, a disintegrator, a turbo type mill, and an annual type mill from the viewpoint of reducing the particle size of coarsely pulverized cellulose. Seeds are preferred.
The hammer mill is an atomizer or sample mill manufactured by Dalton Corporation, the disintegrator is a free crusher manufactured by Nara Kikai Seisakusho Co., Ltd., the turbo type mill is a turbo mill manufactured by Turbo Kogyo Co., Ltd., and the annual type mill is Earth Co., Ltd. Each of Technica's Cryptron series can be preferably used.
The above-mentioned high-speed rotary pulverizer can be used alone or in combination of two or more.

The particle size reduction treatment can be performed by either batch treatment or continuous treatment, but continuous treatment is desirable from the viewpoint of productivity. When the continuous treatment is performed, the preferable range of the treatment speed in the particle size reduction treatment is the same as the treatment speed in the coarse pulverization treatment.

The peripheral speed of the rotor of the high-speed rotary fine pulverizer is preferably 40 m / s or more, more preferably 50 m / s or more, from the viewpoint of efficiently obtaining small particle size cellulose.
The temperature at the time of pulverization is not particularly limited, but is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, preferably 200 ° C. or lower, from the viewpoint of preventing coloration of cellulose or reducing the molecular weight due to heat and from the viewpoint of cost. More preferably, it is 150 ° C. or lower.

By the above pulverization treatment, powdering and low crystallization of the cellulose-containing raw material proceed, and powdered cellulose suitable for the production method of the present invention can be obtained.
From the viewpoint of improving the water solubility of the finally obtained cellulose derivative and from the viewpoint of improving the reactivity with the reactant used in the step (II), the powdered cellulose obtained after the pulverization treatment has a crystallization index thereof. Is -3.5% or less, preferably -4.0% or less, more preferably -5.0% or less, still more preferably -7.0% or less, and from the viewpoint of productivity, it is preferable. It is -30.0% or more. When the crystallization index of powdered cellulose exceeds -3.5%, the transparency of the finally obtained aqueous solution of the cellulose derivative is lowered. Further, when the crystallization index of powdered cellulose is high, the reaction rate of the crystalline portion and the amorphous portion is likely to be different, and the reaction uniformity with the reactant is lowered.

From the viewpoint of improving the transparency of the aqueous solution of the cellulose derivative finally obtained, the powdered cellulose obtained after the pulverization treatment has a water content of less than 2.5% by mass, preferably 2.3% by mass or less. It is preferably 2.1% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.8% by mass or less. From the viewpoint of cost, the water content is 0% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1.0% by mass or more.

Further, from the viewpoint of the productivity of the powdered cellulose, the powdered cellulose obtained after the pulverization treatment has a D50 of preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more. Further, from the viewpoint of reaction uniformity with the reactant used in step (II) and from the viewpoint of improving the water solubility of the finally obtained cellulose derivative, D50 is preferably 300 μm or less, more preferably 200 μm or less. More preferably, it is 100 μm or less.

In step (I), it is preferable to carry out the pulverization treatment without adding the basic compound. If the basic compound stays in the crusher, it may cause contamination and destabilization of product quality, but this can be avoided.

<Step (II)>
In the step (II), 0.5 mol of the powdered cellulose obtained in the step (I) and the reactant were added to 1 mol of the anhydroglucose unit (AGU) of the cellulose constituting the main chain of the powdered cellulose. A cellulose derivative is obtained by reacting in the presence of a basic compound having an equivalent amount or more and 3.0 molar equivalents or less.
Alkaline cellulose produced from powdered cellulose and a basic compound has high reaction activity with a reactant. The basic compound also acts as a reaction catalyst in the reaction between cellulose and the reactant. Therefore, the cellulose derivative can be efficiently obtained by reacting the powdered cellulose with the reactant in the presence of a predetermined amount of the basic compound. In addition, the finally obtained aqueous solution of the cellulose derivative has high transparency.

More specifically, the reaction in step (II) is preferably carried out by adding a reactant in the presence of the above-mentioned predetermined amount of the basic compound while stirring the powdered cellulose.
The order in which the basic compound and the reactant are added is not particularly limited, but it is preferable to mix the powdered cellulose and the basic compound and then add the reactant to cause the reaction. This is because the alkali cellulose having high reaction activity is produced by mixing the powdered cellulose and the basic compound, so that the subsequent reaction with the reactant proceeds efficiently.

The reaction of step (II) is preferably carried out in a solid phase state. The reaction in the solid phase state refers to a reaction in a state in which a liquid phase is substantially absent, and is different from a reaction in a solution or a suspension.
By carrying out the reaction of step (II) in a solid phase state, the reaction between the powdered cellulose and the reactant proceeds efficiently. Further, for example, when a large excess of water is present in the reaction system of step (II), a hydration reaction (side reaction) of the epoxy alkane or the like occurs when a hydroxyalkylating agent such as an epoxy alkane described later is used as the reactant. It occurs, and the formation of by-products and the decrease in yield are likely to occur. Therefore, by carrying out the reaction of step (II) in a solid phase state and reducing the amount of water during the reaction, the side reaction can be suppressed and the yield can be improved.

The water content during the reaction in the step (II) is preferably more than 0% by mass, more than 0% by mass, based on the cellulose in the powdered cellulose from the viewpoint of uniformly dispersing the basic compound and the reactant in the powdered cellulose. It is preferably 2.0% by mass or more, further preferably 5.0% by mass or more, still more preferably 10% by mass or more, and even more preferably 15% by mass or more. Further, from the viewpoint of suppressing side reactions and improving the yield, it is preferably 100% by mass or less, more preferably 85% by mass or less. In particular, from the viewpoint of suppressing the above-mentioned side reaction, the amount of water during the reaction when the powdered cellulose is reacted with a hydroxyalkylating agent such as epoxyalkane in the step (II) is further increased with respect to the cellulose in the powdered cellulose. It is preferably 70% by mass or less, and even more preferably 55% by mass or less. In the present invention, if the water content during the reaction in step (II) is 100% by mass or less, the reaction is in a solid phase state.
The amount of cellulose in the powdered cellulose means a value obtained by subtracting the amount of water in the powdered cellulose from the mass of the powdered cellulose. The amount of water during the reaction in step (II) means the total amount of water in the powdered cellulose provided in step (II) and the amount of water added in step (II).

For example, in step (II), first, powdered cellulose, a basic compound, and water if necessary are added, mixed, and stirred. When water is added, the amount of water added during the reaction in step (II) is preferably adjusted to be within the above range.
When water is added, the order of addition of the basic compound and water is not particularly limited, and (i) a method of adding water after the addition of the basic compound, (ii) a method of adding the basic compound and water at the same time, ( iii) Any method may be used in which the basic compound is dissolved in part or all of the water to which the basic compound is added and added in the form of an aqueous solution. From the viewpoint of operability in manufacturing, the method (iii) is preferable.

(Basic compound)
Examples of the basic compound include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide, and tertiary amines such as trimethylamine and triethylamine. Kind and the like. Among these, one or more selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides is preferable, alkali metal hydroxides are more preferable, and the group consisting of sodium hydroxide and potassium hydroxide One or more selected are more preferred, and sodium hydroxide is even more preferred.
The above basic compounds can be used alone or in combination of two or more.
The amount of the basic compound used is 0.5 mol with respect to 1 mol of AGU of the powdered cellulose from the viewpoint of efficiently advancing the reaction between the powdered cellulose and the reactant and the transparency of the aqueous solution of the obtained cellulose derivative. It is equal to or more than, preferably 0.7 molar equivalent or more, and more preferably 0.8 molar equivalent or more. When the amount of the basic compound used is less than 0.5 molar equivalent to 1 mol of AGU of powdered cellulose, the transparency of the finally obtained aqueous solution of the cellulose derivative is lowered. In addition, the reaction rate with the reactant is also reduced.
On the other hand, when a basic compound is used in a large excess with respect to the AGU of powdered cellulose, by-products increase in the reaction with the reactant and the yield (reactant standard) decreases, and the excess basic compound The removal process is also complicated. Therefore, the amount of the basic compound used in the step (II) is 3.0 molar equivalents or less, preferably 2.5 molar equivalents or less, and more preferably 2.0 molar equivalents, relative to 1 mol of AGU of powdered cellulose. Hereinafter, it is more preferably 1.5 molar equivalents or less, and even more preferably 1.2 molar equivalents or less.

As a method for adding the basic compound, a method of spraying an aqueous solution of the basic compound onto the powdered cellulose is preferable from the viewpoint of uniformly dispersing the basic compound in the powdered cellulose.

From the viewpoint of activating cellulose, the temperature at which powdered cellulose, a basic compound, and water as required are added and stirred is preferably 35 ° C. or higher, more preferably 40 ° C. or higher, and of cellulose. From the viewpoint of suppressing a decrease in the degree of polymerization, the temperature is preferably 90 ° C. or lower, more preferably 80 ° C. or lower.
The stirring time is preferably 0.1 hour or more, more preferably 0.2 hours or more, from the viewpoint of the production efficiency of alkaline cellulose. From the viewpoint of productivity, it is preferably 24 hours or less, and more preferably 12 hours or less.
From the viewpoint of avoiding coloring of cellulose and from the viewpoint of avoiding a decrease in molecular weight due to cleavage of the cellulose chain during the reaction, it is preferable to carry out the above stirring and the subsequent reaction in an atmosphere of an inert gas such as nitrogen.

(Reactant)
Then, the reactant is added to the mixture of the powdered cellulose, the basic compound, and water obtained by the above method, and the powdered cellulose is reacted with the reactant.
The reactant used in the step (II) is not particularly limited as long as it is a compound capable of reacting with a primary or secondary hydroxyl group of cellulose to introduce a substituent, but when cellulose ether is obtained as a cellulose derivative, it is not particularly limited. , An etherifying agent is used. When the cellulose derivative produced by the production method of the present invention is hydroxyalkyl cellulose, cationized cellulose, or cationized hydroxyalkyl cellulose, the reactant used in step (II) is from a hydroxyalkylating agent and a cationizing agent. It is one or more species selected from the group.
When a hydroxyalkylating agent and a cationizing agent are used as the reactants, the order in which the reactants are added is not particularly limited, but the powdered cellulose may be first reacted with the hydroxyalkylating agent and then reacted with the cationizing agent. preferable. With this reaction sequence, the transparency of the aqueous solution of the obtained cellulose derivative (cationized hydroxyalkyl cellulose) becomes better. It is considered that the reason is that by adding the hydroxyalkylating agent, which is a reactant having a smaller molecular volume, first, the addition of the reactant (cationizing agent) to be reacted next tends to proceed uniformly.

[Hydroxyalkylating agent]
When hydroxyalkyl cellulose or cationized hydroxyalkyl cellulose is obtained as a cellulose derivative by the production method of the present invention, a hydroxyalkylating agent is used as a reactant.
Specific examples of the hydroxyalkylating agent include epoxyalkanes, alkylglycidyl ethers, alkylhalohydrin ethers and the like. Among these, one or more selected from the group consisting of epoxy alkanes and alkyl glycidyl ethers is preferable, and epoxy alkanes are more preferable, from the viewpoint of no salt formation during the reaction.
Examples of the epoxy alkane include carbons such as ethylene oxide, propylene oxide, butylene oxide, 1,2-epoxyhexane, 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxide dodecane, and 1,2-epoxyoctadecane. Epoxide alkanes having a number of 2 or more and 20 or less can be mentioned. The carbon number of the epoxy alkane is preferably 3 or more, preferably 18 or less, more preferably 12 or less, still more preferably 8 or less, still more preferably 6 or less, still more preferably 4 or less.

Among the above, as the hydroxyalkylating agent, one or more selected from the group consisting of ethylene oxide, propylene oxide, and butylene oxide is preferable, and propylene oxide is more preferable.

The amount of the hydroxyalkylating agent used is not limited, and may be appropriately adjusted according to the desired introduction amount. From the viewpoint of improving the water solubility of the obtained cellulose derivative, the amount of the hydroxyalkylating agent used is preferably 0.10 mol or more, more preferably 0. Mol, per 1 mol of AGU of the powdered cellulose used in the step (II). It is 20 mol or more, more preferably 0.50 mol or more, still more preferably 1.0 mol or more, still more preferably 2.0 mol or more. From the viewpoint of cost, the amount of the hydroxyalkylating agent used is preferably 20 mol or less, more preferably 10 mol or less, still more preferably 8.0, per 1 mol of AGU of the powdered cellulose used in the step (II). It is mol or less, more preferably 5.0 mol or less.

[Cationizing agent]
When cationized cellulose or cationized hydroxyalkyl cellulose is obtained as a cellulose derivative by the production method of the present invention, a cationizing agent is used as a reactant.
The cationizing agent used in the present invention is preferably a compound represented by the following general formula (1) or (2).

In the general formulas (1) and (2), R ^{1 to} R ³ independently represent a linear or branched hydrocarbon group having 1 or more and 4 or less carbon atoms, and X represents a halogen atom. In the general formula (2), Z represents a halogen atom.
From the viewpoint of water solubility of the obtained cellulose derivative, R ^{1 to} R ³ are preferably an alkyl group having 1 or more carbon atoms and 6 or less carbon atoms, more preferably one or more selected from the group consisting of a methyl group and an ethyl group, and the methyl group is more preferable. More preferred. Examples of X include chlorine, bromine and iodine, but chlorine or bromine is preferable, and chlorine is more preferable, from the viewpoint of water solubility of the obtained cellulose derivative.
In the general formula (2), Z is preferably chlorine or bromine from the viewpoint of water solubility of the obtained cellulose derivative, and more preferably chlorine.

Specific examples of the compound represented by the general formula (1) or (2) include chlorides, bromides or iodides such as glycidyltrimethylammonium, glycidyltriethylammonium, and glycidyltripropylammonium, and 3-chloro-. Chlorides such as 2-hydroxypropyltrimethylammonium, 3-chloro-2-hydroxypropyltriethylammonium, or 3-chloro-2-hydroxypropyltripropylammonium, 3-bromo-2-hydroxypropyltrimethylammonium, 3-bromo- Boiled compounds such as 2-hydroxypropyltriethylammonium and 3-bromo-2-hydroxypropyltripropylammonium, 3-iodo-2-hydroxypropyltrimethylammonium, 3-iodo-2-hydroxypropyltriethylammonium, 3-iodo-2 -Iodides such as hydroxypropyltripropylammonium and the like can be mentioned.
Among these, from the viewpoint of availability, chlorides or bromides of glycidyltrimethylammonium or glycidyltriethylammonium, chlorides such as 3-chloro-2-hydroxypropyltrimethylammonium and 3-chloro-2-hydroxypropyltriethylammonium, Bromides such as 3-bromo-2-hydroxypropyltrimethylammonium and 3-bromo-2-hydroxypropyltriethylammonium are preferable, and glycidyltrimethylammonium chloride or 3-chloro-2-hydroxypropyltrimethylammonium chloride is more preferable. -Chloro-2-hydroxypropyltrimethylammonium chloride is more preferred.
These cationizing agents can be used alone or in combination of two or more.

The amount of the cationizing agent used is not particularly limited, and may be appropriately adjusted according to the desired amount of the cationic group introduced and the yield of the reaction.
From the viewpoint of improving the water solubility of the obtained cellulose derivative, the amount of the cationizing agent used is preferably 0.001 mol or more, more preferably 0.01 mol, per 1 mol of AGU of the powdered cellulose used in the step (II). It is mol or more, more preferably 0.10 mol or more, still more preferably 0.30 mol or more. From the viewpoint of cost, the amount of the cationizing agent used is preferably 5.0 mol or less, more preferably 3.0 mol or less, still more preferably 3.0 mol or less, per 1 mol of AGU of the powdered cellulose used in the step (II). It is 2.0 mol or less, more preferably 1.5 mol or less, still more preferably 1.0 mol or less, still more preferably 0.80 mol or less.

As a method for adding the reactant, a method of spraying the reactant or the reactant solution onto the powdered cellulose is preferable from the viewpoint of uniformly dispersing the reactant in the powdered cellulose.

The reaction temperature and reaction time with the reactant in step (II) are not particularly limited and can be appropriately selected depending on the type of the reactant to be used and the like.
For example, when the reactant is a hydroxyalkylating agent, the reaction temperature is preferably 0 ° C. or higher, more preferably 20 ° C. or higher, still more preferably 25 ° C. or higher, from the viewpoint of improving the reaction rate. Further, from the viewpoint of stability of powdered cellulose or cellulose derivative, the temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower.

When the hydroxyalkylating agent is a gas under the above reaction conditions, the reaction is preferably carried out under pressurized conditions. The reaction pressure at that time can be appropriately adjusted by adjusting the boiling point of the hydroxyalkylating agent, the abundance of the hydroxyalkylating agent in the system, the reaction temperature, and the like. The pressure at the time of reaction is usually 0.001 MPa or more and 10 MPa or less (gauge pressure), preferably 0.005 MPa or more, more preferably 0.02 MPa or more, and 1 MPa or less from the viewpoint of reaction rate and equipment load. It is preferably 0.5 MPa or less, more preferably 0.5 MPa or less.

When the reactant is a cationizing agent, the reaction temperature is preferably 30 ° C. or higher, more preferably 35 ° C. or higher, from the viewpoint of improving the reaction rate. Further, from the viewpoint of stability of powdered cellulose or cellulose derivative, the temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower.

When a hydroxyalkylating agent and a cationizing agent are used as the reactants, the preferred production method is as follows.
First, powdered cellulose, a basic compound, and water if necessary are added and mixed by the above-mentioned method, and after stirring, a hydroxyalkylating agent is added and reacted to obtain hydroxyalkyl cellulose. Then, a cationizing agent is added and reacted with hydroxyalkyl cellulose to obtain cationized hydroxyalkyl cellulose. With this reaction sequence, the transparency of the aqueous solution of the obtained cationized hydroxyalkyl cellulose, which is a cellulose derivative, becomes better.
The types and amounts of each component used, reaction conditions, and preferred embodiments thereof are the same as described above.

The apparatus used in the step (II) preferably includes a mechanical stirring type mixer having a stirring blade inside and a spraying device for spraying the basic compound and the reactant into the stirring tank.
The mechanical stirring type mixer is not particularly limited, but is highly airtight and pressurized from the viewpoint of enabling the reaction above the boiling point of the reactant in order to increase the reaction rate between the powdered cellulose and the reactant. Those capable of operation are preferable, and those capable of decompression operation are preferable from the viewpoint of dehydration operation and gas phase replacement operation. Specific examples thereof include a high-speed stirring type mixer and a double-arm type mixer, and the high-speed stirring type mixer is preferable from the viewpoint of making the reaction more uniform.
Examples of the high-speed stirring type mixer include a horizontal axis rotary type mixer and a vertical axis rotary type mixer.
Among the horizontal axis rotary mixers, a horizontal axis rotary mixer equipped with excavator blades and multi-stage chopper blades is preferable, and such a commercially available product is a Reedige mixer (manufactured by Chuo Kiko Co., Ltd., Redige Co., Ltd.). ), Proshare mixer (manufactured by Pacific Machinery & Engineering Co., Ltd.).
Among the vertical axis rotary mixers, a vertical axis rotary mixer equipped with a multi-stage chopper blade is preferable, and such commercially available products include a high speed mixer (manufactured by EarthTechnica Co., Ltd.) and a vertical granulator (stock). (Company Paulec) is mentioned, and among them, a high-speed mixer is preferable.

The spraying device for supplying the basic compound and the reactant into the mechanical stirring type mixer is not particularly limited. For example, a spraying device having a spraying nozzle such as a one-fluid nozzle or a two-fluid nozzle is preferable.
The spray pattern by the spray nozzle is not particularly limited, and examples thereof include a filled cone, an empty cone, a filled pyramid, and a fan shape.

After completion of the reaction in step (II), the cellulose derivative can also be isolated by performing purification operations such as neutralization of the basic compound and washing with hydrous isopropanol, hydrous acetone solvent and the like, if necessary.

In the cellulose derivative in which epoxyalkane is used as a reactant and an alkyleneoxy group is introduced, the average number of moles of alkyleneoxy group added per mole of AGU of the cellulose constituting the cellulose main chain is determined from the viewpoint of the transparency of the obtained aqueous solution. It is preferably 0.10 or more, more preferably 0.20 or more, still more preferably 0.50 or more, still more preferably 1.0 or more. From the viewpoint of cost, it is preferably 20 or less, more preferably 10 or less, still more preferably 8.0 or less, still more preferably 5.0 or less, still more preferably 3.0 or less.
Specifically, the average number of moles of alkyleneoxy groups added can be measured by the method described in Examples.

Further, in a cellulose derivative in which a cationic agent is used as a reactant and a cationic group is introduced, the degree of substitution of the cationic group with respect to 1 mol of AGU of the cellulose constituting the cellulose main chain (hereinafter, also referred to as “cation substitution degree”) is determined. From the viewpoint of the transparency of the obtained aqueous solution, it is preferably 0.001 or more, more preferably 0.01 or more, and further preferably 0.10 or more. Further, from the viewpoint of cost, it is preferably 5.0 or less, more preferably 3.0 or less, still more preferably 2.0 or less, still more preferably 1.5 or less, still more preferably 1.0 or less, still more. It is preferably 0.80 or less, more preferably 0.50 or less, and even more preferably 0.30 or less.
Specifically, the degree of cation substitution can be measured by the method described in Examples.

The cellulose derivative obtained by the production method of the present invention can be used in a wide range of fields such as compounding ingredients of hair cosmetic compositions such as shampoos, rinses, treatments and conditioners, dispersants, modifiers and flocculants. it can. The cellulose derivative may be used in a powder state, or may be dissolved in water and used in an aqueous solution state.

<Manufacturing of aqueous cellulose derivative solution>
The method for preparing an aqueous solution of the cellulose derivative obtained by the production method of the present invention is not particularly limited. For example, when the cellulose derivative is cationized hydroxypropyl cellulose, it is mixed with water, preferably 0.5 to 0.5 at 40 to 90 ° C. It can be prepared by stirring for 12 hours. The solid content concentration of the aqueous solution is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and from the viewpoint of ease of preparation of the aqueous solution, preferably 20% by mass or less, more preferably 15% by mass. % Or less, more preferably 10% by mass or less.

Various additives such as a neutralizing agent and a preservative may be added to the aqueous solution of the cellulose derivative as long as the effects of the present invention are not impaired. As the neutralizing agent, either an inorganic acid or an organic acid can be used, but an organic acid is preferable, and for example, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, tartronic acid, malic acid, tartrate acid, oxyphthalic acid and citric acid. And so on. Among them, a dicarboxylic acid having a hydroxyl group and having 2 or more and 8 or less carbon atoms is preferable, one or more selected from malic acid and tartaric acid is more preferable, and malic acid is further preferable.
Examples of the preservative include benzyl alcohol, paraoxybenzoic acid ester, benzoic acid, sorbic acid, dehydroacetic acid and the like.
The blending amount of the additive in the aqueous cellulose derivative solution is usually 0.001% by mass or more and 5.0% by mass or less.

The aqueous solution obtained as described above may be filtered using a mesh having an opening of 50 μm or more and 300 μm or less, if necessary.
The cellulose derivative obtained by the production method of the present invention has a light transmittance of a 2% by mass aqueous solution at a wavelength of 600 nm of preferably 40% or more, more preferably 42% or more, still more preferably 45% or more, still more preferably 48%. Above, even more preferably 50% or more. When the transmittance is 40% or more, the transparency is good, and when blended in shampoo, the finger passage and foaming after drying are also good. Specifically, the light transmittance of the aqueous solution of the cellulose derivative can be measured by the method described in Examples.

In the following examples, "%" means "mass%" unless otherwise specified and the crystallization index (%) is excluded.

(1) Measurement of Moisture Content The water content of pulp and powdered cellulose was measured using an infrared moisture meter (“FD-610” manufactured by Kett Scientific Research Institute, Inc.). Using 5 g of the sample per measurement, the sample was flattened and measured at a temperature of 120 ° C., and the point at which the mass change rate for 30 seconds was 0.1% or less was defined as the end point of the measurement. The measured value of water content was converted into mass% with respect to cellulose to obtain the value of each water content.

(2) Calculation of crystallization index The X-ray diffraction intensity of powdered cellulose was measured using an X-ray diffractometer (“MiniFlexII” manufactured by Rigaku Co., Ltd.) under the following conditions, and based on the above formula (1). The type I crystallization index of cellulose was calculated.
The measurement conditions were X-ray source: Cu / Kα-radiation, tube voltage: 30 kV, tube current: 15 mA, measurement range: diffraction angle 2θ = 5 to 35 °, and X-ray scan speed of 40 ° / min. The measurement sample was prepared by compressing pellets having an area of 320 mm ² × thickness of 1 mm.

(3) Measurement of Medium Volume Particle Size (D50) D50 of powdered cellulose is a dry method (tornado method) using a laser diffraction / scattering type particle size distribution measuring device (“LS13 320” manufactured by Beckman Coulter Co., Ltd.). ). Specifically, 20 mL of powdered cellulose was charged into a cell and sucked for measurement.

(4) Evaluation of transparency of aqueous solution (measurement of light transmittance)
The aqueous solution of the cellulose derivative (cationized hydroxypropyl cellulose) obtained in each example was diluted with ion-exchanged water to prepare a measurement sample having a concentration of 2% by mass. This measurement sample was placed in a cell having an optical path length of 10 mm, and the transmittance (T%) at a wavelength of 600 nm was measured using a spectrophotometer (manufactured by Hitachi, Ltd., model U-2000A).

(5) Calculation of average number of moles of propyleneoxy group added and degree of cation substitution The average number of moles of propyleneoxy group added and degree of cation substitution in the cellulose derivative (cationized hydroxypropyl cellulose: C-HPC) obtained in each example Was obtained according to the analysis method for hydroxypropyl cellulose described in the 15th revised Japanese Pharmacy, except that the measured value of the amount of chlorine element by element analysis and the analysis target were C-HPC instead of hydroxypropyl cellulose. Obtained from the value.
Specifically, the aqueous solution of C-HPC obtained in each example was purified by a dialysis membrane (molecular weight cut off: 1000), and then the aqueous solution was freeze-dried to obtain purified C-HPC. The chlorine content (%) of the obtained C-HPC was measured by elemental analysis, and the number of cation groups contained in the purified C-HPC and the number of chloride ions as counterions were approximated to be the same. , The amount (a (mol / g)) of the cation group contained in the C-HPC unit mass was determined from the following calculation formula (2).
a (mol / g) = Chlorine content (%) / (35.5 × 100) obtained from elemental analysis (2)
Next, the hydroxypropoxy group is contained in the purified C-HPC according to the "Analytical Method for Hydroxypropyl Cellulose" described in the 15th revised Japanese Pharmacopoeia, except that the analysis target is purified C-HPC instead of hydroxypropyl cellulose. The amount (%) was measured. From the following calculation formula (3), the hydroxypropoxy group content [formula (-OC ₃ H ₆ OH) = 75.09] (b (mol / g)) was calculated.
b (mol / g) = hydroxypropoxy group content (%) / (75.09 × 100) determined from gas chromatograph analysis (3)
From the obtained a and b and the following formulas (4) and (5), the degree of cation substitution (k) of C-HPC and the average number of moles of propyleneoxy group added (m) were calculated.
a = k / (162 + k × 151.5 + m × 58) (4)
b = m / (162 + k × 151.5 + m × 58) (5)
[In the formula, k indicates the degree of cation substitution of C-HPC. m indicates the average number of moles of propyleneoxy group added. ]

Example 1 (Production of Cellulose Derivative)
<Step (I)>
(1) Cutting treatment As a cellulose-containing raw material, sheet-shaped wood pulp (“BioflocHV +” manufactured by Tembec, crystallization index: 82%, water content: 8.5% by mass) was cut into about 3 mm × 1. It was cut into a 5 mm × 1 mm chip shape.
(2) Drying treatment The pulp obtained by the cutting treatment of (1) above is subjected to a twin-screw horizontal stirring dryer (“two-screw paddle dryer, NPD-3W (1/2)” manufactured by Nara Kikai Seisakusho Co., Ltd.). The pulp was dried by continuous treatment. The heating medium of the dryer was steam at 150 ° C., the pulp supply rate was 45 kg / h, and the treatment was performed under atmospheric pressure.
(3) Cellulose Coarse Grinding Treatment The dried pulp obtained by the drying treatment of (2) above is subjected to a continuous vibration mill (“Vibro Mill, YAMT-200” manufactured by Eura Techno Co., Ltd., capacity of the first and second crushing chambers: (112 L, made of stainless steel) was roughly pulverized. In the first and second crushing chambers, 80 stainless steel round rod-shaped crushing media (rods) having a diameter of 30 mm and a length of 1300 mm were housed. The dry pulp was supplied at 17.5 kg / h under the conditions of a continuous vibration mill having a frequency of 16.7 Hz and an amplitude of 13.4 mm. In Table 1, the supply rate of the dried pulp is represented as the "crushing process rate" in the step (I).
(4) Cellulose particle size reduction treatment The coarsely crushed cellulose obtained by the coarse crushing treatment of (3) above is pulverized using a high-speed rotary pulverizer (manufactured by Dalton Corporation, product name "Atomizer AIIW-5 type"). The particle size was reduced. A screen with a mesh opening of 1.0 mm is attached, the rotor peripheral speed is driven at 4400 r / min (50 m / s) at a temperature of 55 ° C., and coarsely crushed cellulose is supplied from the raw material supply unit at the same supply speed as the coarse crushing process. , Powdered cellulose was recovered from the outlet. The obtained powdered cellulose had a water content of 1.7% by mass, a crystallization index of -10.7%, and a volume median particle diameter (D50) of 69.5 μm.
The processes (1) to (4) were continuously carried out.

<Step (II)>
100 parts by mass of the powdered cellulose obtained in the step (I) was put into a reaction tank with a jacket to which the main wing and the chopper wing were attached as a stirrer as a mass part excluding water. After replacing the gas phase part in the tank with nitrogen, 24.5 parts by mass of sodium hydroxide which is a basic compound (1 mol of AGU of powdered cellulose) under stirring at a peripheral speed of the main blade of 3 m / s and a chopper blade of 16 m / s. The aqueous sodium hydroxide solution obtained by mixing 1.0 molar equivalent) and water was sprayed and charged. The amount of water used to prepare the aqueous sodium hydroxide solution was adjusted so that the total amount of the amount of water and the water contained in the powdered cellulose was 49.8 parts by mass as the amount of water in the reaction system. .. Further, the internal temperature was adjusted to 50 ° C. ± 5 ° C. with jacket warm water, and mixing was continued for 2 hours. Next, while adjusting the internal temperature to be maintained at 37 ° C. to 47 ° C., 142.9 parts by mass of propylene oxide (PO) (4.0 mol with respect to 1 mol of AGU of powdered cellulose) was added to the internal pressure of 0.07 to 0. It was charged over about 8 hours so as to maintain the pressure at 10 MPa (gauge pressure). After adding all the propylene oxide, stirring and temperature control were continued for about 3 hours until the internal pressure was sufficiently stabilized. The water content at the time of the reaction at this time was 49.8% by mass with respect to cellulose. Subsequently, a 70% by mass aqueous solution (water content 30%, purity 90% or more) of 3-chloro-2-hydroxypropyltrimethylammonium chloride (HAC), which is a cationizing agent, manufactured by Yokkaichi Chemical Co., Ltd., product name "CTA-65" 112.0 parts by mass (0.68 mol as HAC with respect to 1 mol of AGU of powdered cellulose) was sprayed and added, and stirring was continued for 2 hours while adjusting the internal temperature to 50 ° C. ± 5 ° C. The water content at the time of the reaction at this time was 83.4% by mass with respect to cellulose. Then, it cooled to an internal temperature of 40 degreeC to obtain cationized hydroxypropyl cellulose which is a cellulose derivative. The total amount charged per unit volume of the reaction tank was 174 kg / m ³ .
The average number of moles of PO added to the cationized hydroxypropyl cellulose was 2.34, and the degree of cation substitution was 0.17.

<Preparation of aqueous solution>
In a stirring tank equipped with an anchor blade, 1165 parts by mass of ion-exchanged water and 100 parts by mass of cationized hydroxypropyl cellulose obtained in step (II) are mixed and dissolved by stirring at 60 to 65 ° C. for 4 hours. I let you. Further, 7 parts by mass of 50% malic acid and 13 parts by mass of benzyl alcohol were mixed, and then the mixing was continued for 3 hours to obtain a cationized hydroxypropyl cellulose aqueous solution. The total amount charged per unit volume of the stirring tank was 900 kg / m ³ .
Using the obtained aqueous solution of cationized hydroxypropyl cellulose, the transparency of the aqueous solution was evaluated by the above method. The results are shown in Table 1.

Examples 2-5
Step (I) was carried out at the pulverization treatment speed shown in Table 1 to obtain powdered cellulose having a water content, a crystallization index and D50 shown in Table 1. Catified hydroxypropyl cellulose and an aqueous solution thereof were produced by the same method as in Example 1 except that this powdered cellulose was used in the step (II), and evaluated by the above method. The results are shown in Table 1.

Example 6
Step (I) was carried out at the pulverization treatment rate shown in Table 1 to obtain powdered cellulose having a water content of 1.8% by mass, a crystallization index of −8.1%, and a volume median particle diameter (D50) of 72.2 μm. .. This powdered cellulose was exposed to the air for 7 days to absorb moisture to obtain a powdered cellulose having a water content of 7.4% by mass and a crystallization index of 8.5%.
Using this powdered cellulose, cationized hydroxypropyl cellulose and an aqueous solution thereof were produced by the same method as in Example 1, and evaluated by the above method. The results are shown in Table 1.

Comparative Examples 1-2
Step (I) was carried out at the pulverization treatment speed shown in Table 1 to obtain powdered cellulose having a water content, a crystallization index and D50 shown in Table 1. Catified hydroxypropyl cellulose and an aqueous solution thereof were produced by the same method as in Example 1 except that this powdered cellulose was used in the step (II), and evaluated by the above method. The results are shown in Table 1.

Comparative Example 3
Cationic hydroxypropyl cellulose, which is a cellulose derivative, was produced by the same method as described in Examples of Patent Document 1. Specifically, it is as follows.
<Step (I)>
(1) Cutting treatment As a cellulose-containing raw material, sheet-shaped wood pulp (manufactured by Tembec, crystallization index: 76%, water content: 7% by mass) is shredded (manufactured by Meiko Shokai Co., Ltd., product name "MSX2000-IVP440F"). It was made into chips.
(2) Drying Treatment The chip-shaped pulp obtained by the cutting treatment of (1) above is dried under reduced pressure at 50 ° C. for 12 hours to obtain chip-shaped dried pulp (moisture content: 0.4% by mass). Obtained.
(3) Cellulose coarse crushing treatment The dried pulp obtained by the drying treatment of (2) above is used as a batch type vibration mill (“MB-1” manufactured by Chuo Kakoki Co., Ltd .: total container volume 3.5 L, φ30 mm as a rod. , 13 rods made of SUS304 having a length of 218 mm and a circular cross-sectional shape, and a filling rate of 57%). The pulverization treatment was carried out for 1 hour in a frequency range of 20 Hz, a total amplitude of 8 mm and a temperature of 30 to 70 ° C. to obtain powdered cellulose (crystallization index: -20.0%, water content: 1.4% by mass).

<Step (II)>
90 g of powdered cellulose (part by mass not containing water) obtained in the above step (I) was charged into a 1 L kneader (manufactured by Irie Shokai Co., Ltd., PNV-1 type) equipped with a recirculation tube, and then 48% water was added. 9.0 g of an aqueous sodium oxide solution (0.2 mol equivalent to 1 mol of AGU of powdered cellulose) was added dropwise, and the kneader was heated to 50 ° C. with warm water and stirred under a nitrogen atmosphere for 3 hours. Then, the kneader is heated to 70 ° C. with warm water, and 11.5 g of glycidyltrimethylammonium chloride (hereinafter, also referred to as “GMAC”, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., water content 20%, purity 90% or more) as a cationizing agent. (0.10 mol with respect to 1 mol of AGU of powdered cellulose) was added dropwise. Then, the mixture was further stirred at 70 ° C. for 3 hours.
Next, the temperature was adjusted to 50 ° C., 34.9 g of ion-exchanged water was added dropwise, and then 161.1 g of propylene oxide (5.0 mol with respect to 1 mol of AGU of powdered cellulose) was added dropwise to consume propylene oxide. The reaction was carried out until the reflux stopped. The water content in the reaction system before dropping propylene oxide was 50.0% by mass with respect to cellulose. The product was then removed from the kneader to give a cationized hydroxypropyl cellulose powder. The average number of moles of PO added to the cationized hydroxypropyl cellulose was 3.20, and the degree of cation substitution was 0.08.
Using the obtained cationized hydroxypropyl cellulose powder, an aqueous solution of cationized hydroxypropyl cellulose was produced in the same manner as in Example 1, and evaluated by the above method. The results are shown in Table 1.

Note)
* 1: Moisture content (mass%) with respect to cellulose
* 2: Molar equivalent to 1 mol of AGU of cellulose
* 3: After the pulverization treatment in step (I), it was exposed to the air to absorb moisture.
* 4: Batch processing was performed.

As is clear from Table 1, Comparative Examples 1 and 2 which do not satisfy at least one of the requirements of the water content and the crystallization index in the step (I), and the comparison in which the amount of the basic compound used in the step (II) is small. Compared with Example 3, in Examples 1 to 6, it can be seen that the 2% by mass aqueous solution of the obtained cellulose derivative (cationized hydroxypropyl cellulose) has a high light transmittance and an aqueous solution having excellent transparency is obtained.
Further, according to the result of Example 6, if the powdered cellulose obtained by the pulverization treatment in the step (I) satisfies the requirements of the present invention (predetermined water content and crystallization index), it is subsequently subjected to moisture absorption or the like. It can be seen that even if the water content and crystallization index of cellulose change, the effects of the present invention can be obtained in the same manner as in Examples 1 to 5 when used as a raw material for producing a cellulose derivative in step (II).

When the cellulose derivative such as cationized hydroxyalkyl cellulose obtained by the production method of the present invention is dissolved in water, a highly transparent aqueous solution can be obtained. The cellulose derivative and its aqueous solution can be blended with various hair cosmetic compositions such as shampoos, conditioners, treatments, and conditioners to supply products with stable quality.

Claims (6)

A method for producing cationized hydroxyalkyl cellulose , which comprises the following steps (I) and (II) . In step (II), powdered cellulose is reacted with a hydroxyalkylating agent, and then a cationizing agent is used. A method for producing cationized hydroxyalkyl cellulose .
Step (I): The cellulose-containing raw material is pulverized to obtain powdered cellulose having a water content of less than 2.5% by mass and a crystallization index of −3.5% or less calculated by the following formula (1). Process Crystallization index (%) = [(I _22.6 −I _18.5 ) / I _22.6 ] × 100 (1)
[In the formula, I _22.6 shows the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) of the cellulose I type crystal in X-ray diffraction, and I _18.5 is the amorphous part (diffraction angle 2θ =). It shows a diffraction intensity of 18.5 °). ]
Step (II): The powdered cellulose obtained in step (I), a hydroxyalkylating agent and a cationizing agent are added to 0 with respect to 1 mol of anhydroglucose unit of the cellulose constituting the main chain of the powdered cellulose. A step of reacting in the presence of a basic compound having an equivalent of 5.5 molar equivalents or more and 3.0 molar equivalents or less to obtain cationized hydroxyalkyl cellulose. The method for producing a cationized hydroxyalkyl cellulose according to claim 1 , wherein the hydroxyalkylating agent is an epoxy alkane having 3 to 12 carbon atoms. The method for producing cationized hydroxyalkyl cellulose according to claim 1 or 2 , wherein the cationizing agent is a compound represented by the following general formula (1) or (2).

(In the general formulas (1) and (2), R ^{1 to} R ³ independently represent a linear or branched hydrocarbon group having 1 to 4 carbon atoms, and X represents a halogen atom (general formula (1) and (2)). In 2), Z represents a halogen atom.) The method for producing cationized hydroxyalkyl cellulose according to any one of claims 1 to 3 , wherein a vibrating rod mill is used for the pulverization treatment. The method for producing cationized hydroxyalkyl cellulose according to claim 4 , wherein a vibrating rod mill and a high-speed rotary pulverizer are used for the pulverization treatment. The method for producing cationized hydroxyalkyl cellulose according to any one of claims 1 to 5 , wherein the reaction in the step (II) is carried out in a solid phase state.