JP6835405B2 - Cleaning method - Google Patents

Description

The present invention relates to a method for cleaning a mechanical stirring mixer.

Cellulose derivatives such as hydroxyalkyl cellulose and cationized products thereof are used as compounding ingredients such as shampoos, rinses, treatments and conditioners, dispersants, modifiers, flocculants and the like, and their uses are diverse.
The cellulose derivative can be produced, for example, by reacting a powdered raw material cellulose with a reactant having a reactive functional group capable of reacting with a hydroxyl group in the cellulose while stirring in a mixer, and the above reaction is carried out in a solid phase. By carrying out in this state, a powdered cellulose derivative can be obtained. The cellulose derivative is discharged from the mixer, and then the inside of the mixer is washed, but after washing, a part of the cellulose derivative may adhere to the inside of the mixer and remain. Contamination is caused if the products remain adhered to the inside of the mixer, and therefore, a cleaning method for the mixer used for manufacturing various products is being studied.

Patent Document 1 discloses a method in which after discharging the cationized hydroxycellulose, the residual cationized hydroxycellulose is washed with an aqueous solution of a hydrophilic organic solvent and discharged.
Patent Document 2 describes, as a method for cleaning a mixing device having a mixing portion having a rotating rotor and a stator combined with the rotor, the rotor is used in an environment of 100 kPa or less while the mixing portion is permeated into water. A method having a vacuum cleaning step of rotating and then draining is disclosed.

JP-A-2002-3502 JP 2015-144996

An object of the present invention is to provide a method capable of effectively cleaning a mechanical stirring mixer used for producing a cellulose derivative or the like, and a method for producing a cellulose derivative including the method.

The present invention relates to the following.
[1] A method for cleaning a mechanical stirring mixer having the following steps (I) to (III).
Step (I): Step of reducing the pressure in the mechanical stirring type mixer to 80 kPa or less Step (II): Step of introducing a cleaning liquid into the mixer after step (I) and stirring under a reduced pressure of 80 kPa or less ( III): A step of setting the pressure in the mixer to atmospheric pressure after the step (II) and then discharging the cleaning liquid [2] A method for producing a cellulose derivative, wherein the production method is step (A): basic. A step of reacting a cellulose-containing raw material and a reactant in a mechanical stirring mixer in the presence of a catalyst to obtain a cellulose derivative, and
Step (B): A step of discharging the cellulose derivative obtained in the step (A) from the mixer.
A method for producing a cellulose derivative, which comprises the above steps (I) to (III).

According to the present invention, the mechanical stirring type mixer used for producing cellulose derivatives and the like can be effectively cleaned by a simple operation, so that contamination due to poor cleaning of the mixer can be prevented even in large-scale production. The product can be manufactured without occurring.

It is sectional drawing which shows one Embodiment of the mechanical stirring type mixer.

In the mechanical stirring type mixer used for producing the cellulose derivative and the like, the product may remain stuck and difficult to remove. In particular, the present invention relates to a residue that is difficult to remove (hereinafter, the residue that is fixed in the mixer is also referred to as “adhesion”) that is stuck in the mechanical stirring type mixer when the reaction is carried out in a solid phase state. The cleaning method and the manufacturing method of are effective.
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.
[Washing method]
The cleaning method of the mechanical stirring mixer of the present invention (hereinafter, also referred to as “cleaning method of the present invention”) has the following steps (I) to (III).
Step (I): Reduce the pressure in the mechanical stirring mixer to 80 kPa or less Step (II): After the step (I), introduce the cleaning liquid into the mixer and stir under reduced pressure of 80 kPa or less. III): A step of setting the pressure in the mixer to atmospheric pressure after the step (II) and then discharging the cleaning liquid. Unless otherwise specified in the present specification, the pressure specified in each step is an absolute pressure.

The cleaning method of the present invention having the above steps is excellent in cleaning effect in a mechanical stirring type mixer (hereinafter, also simply referred to as “mixer”). The reason can be considered as follows.
In the present invention, the pressure inside the mixer is reduced in step (I), and then the cleaning liquid is introduced in step (II). When the cleaning liquid is introduced after depressurizing the inside of the mixer, the cleaning liquid is vigorously supplied into the mixer, which has the effect of scraping off the deposits in the mixer. Further, when the pressure inside the mixer is reduced after the cleaning liquid is introduced, the cleaning liquid may volatilize and adhere to the pressure reducing line to contaminate the pressure reducing line. However, this problem can be avoided by the method of the present invention.
Further, by keeping the pressure inside the mixer at 80 kPa or less from the step (I) to the step (II), the permeation of the cleaning liquid into the deposit is promoted and the foaming of the cleaning liquid is suppressed, so that the deposit is suppressed. It is considered that the scraping effect is further improved.

<Mechanical stirring type mixer>
The mechanical stirring mixer used in the present invention has at least a stirring blade in the reaction vessel. In the present invention, "inside the mixer" means the inside of the reaction vessel of the mixer unless otherwise specified. From the viewpoint of enabling the reaction and washing under reduced pressure, the mixer is preferably one having high airtightness and capable of depressurizing operation. Further, from the viewpoint of increasing the reaction rate in the production of the product, those capable of pressurization operation are preferable.
Examples of the mechanical stirring type mixer include a high-speed stirring type mixer and a double-armed type mixer. From the viewpoint of improving the reaction uniformity during the production of the product and from the viewpoint of cleanability, the high-speed stirring type mixer is used. preferable. Examples of the high-speed stirring mixer include a vertical-axis rotary mixer and a horizontal-axis rotary mixer. When the product is a cellulose derivative described later, the horizontal-axis rotary type is used from the viewpoint of efficient commercialization. A mixer is more preferred.

Examples of the vertical axis rotary mixer include a high-speed mixer (manufactured by EarthTechnica Co., Ltd.) and a vertical granulator (manufactured by Paulek Co., Ltd.), and among them, the high-speed mixer is preferable. In addition, Hiflex Gural (manufactured by EarthTechnica Co., Ltd.), New Speed Kneader (manufactured by Okada Seiko Co., Ltd.), and SPG mixer (manufactured by Dalton Corporation) can also be used.
Examples of the horizontal axis rotary mixer include a Redige mixer (manufactured by Chuo Kiko Co., Ltd. and Redige Co., Ltd.) and a Proshare mixer (manufactured by Pacific Machinery & Engineering Co., Ltd.), and the Redigge mixer is particularly preferable. In addition, Spartan Luzer (manufactured by Dalton Corporation) and Apex Granulator (manufactured by Pacific Machinery & Engineering Co., Ltd.) can also be used.

The stirring blades used in the mechanical stirring type mixer are blade type, arm type, ribbon type, multi-stage blade type, double arm type, excavator type such as Becker excavator, plow-shaped excavator, sawtooth excavator, and biaxial blade. Examples include molds, three blades, flat blades, and C type blades. Excavators such as Becker excavators, plow-shaped excavators, and sawtooth-shaped excavators, 3-blades, flat blades, and C-type blades are preferable from the viewpoint of enhancing the reaction uniformity during production of the product and from the viewpoint of cleanability.

The mechanical stirring type mixer may have a chopper blade as an aileron in addition to the stirring blade as the main blade. Examples of the mixer having a chopper blade include a horizontal axis rotary mixer such as a proshare mixer and a radige mixer, and a vertical axis rotary mixer such as a high speed mixer and a vertical granulator. Among these, a horizontal axis rotary mixer is preferable, and a Ladige mixer is more preferable, from the viewpoint of enhancing the reaction uniformity during the production of the product.

(Liquid addition nozzle)
The mechanical stirring type mixer may be provided with a liquid addition nozzle for charging a catalyst, a reactant, or the like into the mixer. The liquid addition nozzle is a nozzle having a mechanism capable of charging a liquid catalyst, a reactant, or the like into the mixer by flowing down, dropping, spraying, or the like.
The liquid addition nozzle is not particularly limited, but for example, a spray nozzle such as a one-fluid nozzle or a two-fluid nozzle is preferable, and the amount of gas introduced into the mixer is relatively small and the pressure in the reaction vessel is unlikely to rise. A one-fluid nozzle is more preferred.
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.
As the spray nozzle, for example, as a one-fluid nozzle, a fan-shaped nozzle, an empty cone nozzle, or a filled cone nozzle manufactured by Ikeuchi Co., Ltd. can be preferably used as a commercially available product.

Since the cleaning method of the present invention has high cleaning properties, even when the mechanical stirring type mixer is provided with the liquid addition nozzle, the liquid addition nozzle is unlikely to be blocked. This effect will be described below.
In the cleaning method of the present invention, the steps (I) to (III) may be performed a plurality of times to clean the inside of the mixer, and then the vacuum drying described later may be performed, but the inside of the mixer is contained in the cleaning liquid immediately before the vacuum drying. If a large amount of deposits are dissolved, the deposits may also adhere to the liquid addition nozzle and dry and solidify during vacuum drying, thereby blocking the liquid addition nozzle. However, in the cleaning method of the present invention, since the amount of deposits dissolved in the cleaning liquid immediately before drying under reduced pressure is small, it is difficult for the deposits to adhere to the liquid addition nozzle.
From the viewpoint of more effectively suppressing the clogging of the liquid addition nozzle, it is preferable to dry the inside of the mixer under reduced pressure while passing gas through the liquid addition nozzle after the step (III). The vacuum drying will be described later.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a mechanical stirring mixer. The mechanical stirring type mixer 10 has a stirring blade 12 which is a main blade in the reaction tank 11, and further includes a liquid addition nozzle 20. The mixer 10 may include a plurality of liquid addition nozzles 20. The liquid addition nozzle 20 is usually installed on the upper part of the mixer 10.
The mixer 10 may have a chopper blade (not shown) as an aileron in addition to the stirring blade 12 which is the main blade. The chopper blade is provided, for example, on the outer periphery of the rotating shaft 12a of the stirring blade in a rotatable state, and is housed in the reaction tank 11.
The mechanical stirring type mixer 10 shown in FIG. 1 is a horizontal axis rotating type mixer in which the rotating shaft 12a of the stirring blade is in a substantially horizontal direction, but the mechanical stirring type mixer used in the present invention is not limited to this embodiment. ..

Inside the mechanical stirring mixer before cleaning, a cellulose derivative or the like is stuck to the wall surface or the stirring shaft. The cleaning method of the present invention effectively cleans the adhered cellulose derivative and the like.
<Step (I)>
Step (I) is a step of reducing the pressure in the mechanical stirring type mixer to 80 kPa or less. By reducing the pressure in the mixer to 80 kPa or less before introducing the cleaning liquid in step (II), the effect of permeating the cleaning liquid into the deposits in the mixer and the effect of scraping the deposits are improved, and the cleaning performance is improved. ..
From the viewpoint of obtaining an excellent cleaning effect, the pressure is preferably 60 kPa or less, more preferably 50 kPa or less, still more preferably 45 kPa or less. From the viewpoint of decompression efficiency, the pressure is preferably 0.01 kPa or more, more preferably 0.1 kPa or more, still more preferably 1 kPa or more, still more preferably 5 kPa or more.
The method of reducing the pressure inside the mixer is not particularly limited, and examples thereof include a method using a vacuum pump. The vacuum pump is preferably connected to the mixer via a bag filter or the like.

<Step (II)>
The step (II) is a step of introducing a cleaning liquid into the mixer after the step (I) and stirring under a reduced pressure of 80 kPa or less. By reducing the pressure in the mixer to 80 kPa or less in the step (I), then introducing the cleaning liquid and stirring under the reduced pressure, the pressure reducing line is compared with the case where the cleaning liquid is introduced at normal pressure and then reduced. It is possible to prevent the cleaning liquid from volatilizing and adhering to the decompression line and contaminating the decompression line. In addition, the permeation of the cleaning liquid into the deposits in the mixer is promoted, and the foaming of the cleaning liquid is suppressed, so that the effect of scraping the deposits is improved.
From the viewpoint of obtaining an excellent cleaning effect, the pressure is preferably 60 kPa or less, more preferably 50 kPa or less, still more preferably 45 kPa or less, still more preferably 30 kPa or less, still more preferably 20 kPa or less. From the viewpoint of decompression efficiency, the pressure is preferably 0.01 kPa or more, more preferably 0.1 kPa or more, still more preferably 1 kPa or more, still more preferably 5 kPa or more.

(Cleaning liquid)
The cleaning liquid used in the step (II) is not particularly limited as long as it can dissolve the deposits to be cleaned, and examples thereof include water, an organic solvent, a surfactant, or a mixture thereof. When the object to be washed is a cellulose derivative described later, water, an organic solvent, or a mixture thereof is preferable, water, a polar solvent, or a mixture thereof is more preferable, and water is further preferable from the viewpoint of cleanability and cost.
Preferred polar solvents include alcohols having 1 to 5 carbon atoms such as isopropyl alcohol, isobutyl alcohol and tert-butyl alcohol; and ether solvents such as 1,4-dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether; Examples thereof include aprotonic polar solvents such as dimethylsulfoxide and dimethylformamide.

^{The amount of the cleaning liquid introduced is preferably 0.1 m 3} or more, more preferably 0.2 m ³ or more, still more preferably 0.2 m 3 or more, as the amount charged per ^{unit capacity (m 3} ) of the mixer from the viewpoint of obtaining an excellent cleaning effect. It is 0.4 m ³ or more, preferably 0.8 m ³ or less, more preferably 0.7 m ³ or less, and further preferably 0.6 m ³ or less from the viewpoint of stirring efficiency.

(Stirring)
From the viewpoint of improving the cleanability, the peripheral speed of stirring in the step (II) is preferably 0.2 m / sec or more, more preferably 0.5 m / sec or more, still more preferably 1.0 m / sec or more, still more. It is preferably 2.0 m / sec or more, more preferably 3.0 m / sec or more, and preferably 20 m / sec or less, more preferably 15 m / sec or less, from the viewpoint of energy efficiency and prevention of foaming of the cleaning liquid. It is even more preferably 12 m / sec or less, even more preferably 10 m / sec or less, and even more preferably 8.0 m / sec or less.
The peripheral speed of stirring means the peripheral speed of the main blade of the mixer (moving speed of the tip of the blade = main blade diameter x pi x rotation speed).

The temperature at the time of stirring in the step (II) is not particularly limited, and can be appropriately selected depending on the boiling point of the cleaning solution and the solubility of deposits. For example, when the cleaning liquid is water and the deposit is a cellulose derivative, the temperature during stirring is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, still more preferably 60 ° C. or higher, from the viewpoint of cleanability. More preferably, it is 65 ° C. or higher. From the viewpoint of energy efficiency, the temperature is preferably 95 ° C. or lower, more preferably 90 ° C. or lower, and even more preferably 85 ° C. or lower.

From the viewpoint of improving the detergency, the stirring in the step (II) is preferably stirred in the forward rotation direction and then in the reverse rotation direction. The peripheral speed and stirring temperature of stirring in the forward rotation and reverse rotation directions may be the same or different, but are preferably the same.

The stirring time in the step (II) is not particularly limited, but from the viewpoint of cleanability, the total stirring time is preferably 0.5 hours or more, more preferably 1 hour or more, still more preferably 2 hours or more, still more preferably 3 It's more than an hour. Further, from the viewpoint of cleaning efficiency, it is preferably 10 hours or less, more preferably 8 hours or less, and further preferably 6 hours or less.
When stirring in the forward rotation direction and the reverse rotation direction, the stirring time in the normal rotation direction is preferably longer than the stirring time in the reverse rotation direction, and the ratio is preferably 20/1 to 2/1, more preferably 15 /. It is 1 to 3/1, more preferably 10/1 to 4/1.

<Step (III)>
The step (III) is a step of setting the pressure in the mixer to atmospheric pressure after the step (II) and then discharging the cleaning liquid. In the step (III), for example, an inert gas such as nitrogen, air, or the like is introduced into the mixer whose pressure is reduced to 80 kPa or less in the step (II) to return the pressure in the mixer to atmospheric pressure. From the viewpoint of product stability, it is preferable to introduce an inert gas such as nitrogen into the mixer to return the pressure in the mixer to atmospheric pressure. Then, the cleaning liquid is discharged from the mixer.

In the cleaning method of the present invention, it is preferable to repeat a series of steps (I) to (III) a plurality of times from the viewpoint of obtaining a more excellent cleaning effect. The number of repetitions is preferably 2 times or more, and from the viewpoint of cleaning efficiency, it is preferably 4 times or less, and more preferably 3 times or less.
When the series of steps (I) to (III) is performed two or more times, the preferred embodiments of the second and subsequent steps (I) to (III) are as follows.
The pressure in the mixer in the second and subsequent cleaning steps (I) is preferably higher than the pressure in the first cleaning. This is because it is possible to prevent the cleaning liquid remaining in the mixer after the first cleaning from volatilizing on the decompression line. From this point of view, the pressure in the mixer in the second and subsequent steps (I) is preferably 60 kPa or less, more preferably 50 kPa or less, still more preferably 45 kPa or less. Further, from the viewpoint of decompression efficiency, the pressure is preferably 10 kPa or more, more preferably 20 kPa or more.
From the viewpoint of cleaning efficiency, the stirring time in the second and subsequent washing steps (II) is preferably shorter than the stirring time in the first washing. From the viewpoint of detergency, the total stirring time is preferably 0.2 hours or more, more preferably 0.5 hours or more, still more preferably 1 hour or more, still more preferably 1.5 hours or more. Further, from the viewpoint of cleaning efficiency, it is preferably 8 hours or less, more preferably 6 hours or less, and further preferably 4 hours or less.
Further, the peripheral speed of stirring in the second and subsequent steps (II) of the washing is preferably slower than the peripheral speed of the first washing, preferably 0.05 m / sec or more, more preferably 0.1 m / sec. The above is more preferably 0.5 m / sec or more, still more preferably 1.0 m / sec or more, still more preferably 2.0 m / sec or more, and is preferable from the viewpoint of energy efficiency and prevention of foaming of the cleaning liquid. Is 15 m / sec or less, more preferably 12 m / sec or less, still more preferably 10 m / sec or less, still more preferably 8.0 m / sec or less, still more preferably 7.5 m / sec or less.
Except for the above, the preferred embodiments in the steps (I) to (III) after the second washing are the same as those in the first washing.

<Drying under reduced pressure>
In the cleaning method of the present invention, it is preferable to dry the inside of the mixer under reduced pressure after the step (III) (hereinafter, also referred to as “vacuum drying step”). When the series of steps (I) to (III) is carried out twice or more, the vacuum drying step is carried out after the completion of the last step (III).
The temperature inside the mixer during drying under reduced pressure is not particularly limited, but the temperature can be the same as the temperature during stirring in step (II). For example, when the cleaning liquid is water, the temperature during vacuum drying is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, still more preferably 60 ° C. or higher, and even more preferably 65 ° C. or higher. From the viewpoint of energy efficiency, it is preferably 95 ° C. or lower, more preferably 90 ° C. or lower, and even more preferably 85 ° C. or lower.
The pressure in the mixer during vacuum drying is preferably low, preferably 10 kPa or less, more preferably 8 kPa or less, still more preferably 5 kPa or less, from the viewpoint of the drying speed. From the viewpoint of decompression efficiency, the pressure is preferably 0.1 kPa or more, more preferably 0.2 kPa or more, still more preferably 0.5 kPa or more.
The vacuum drying time is not particularly limited, but is preferably 0.2 hours or more, more preferably 0.5 hours or more, preferably 6 hours or less, and more preferably 3 hours or less.

When the mechanical stirring type mixer used in the present invention is provided with a liquid addition nozzle, it is preferable to dry the inside of the mixer under reduced pressure while passing gas through the liquid addition nozzle after the step (III). The deposits dissolved in the cleaning liquid may also adhere to the liquid addition nozzle, which may dry and solidify during vacuum drying to block the liquid addition nozzle. However, this is because it is possible to effectively prevent the liquid addition nozzle from being blocked by drying the inside of the mixer under reduced pressure while passing gas through the liquid addition nozzle.
The gas to be circulated is preferably an inert gas such as nitrogen or argon, and more preferably nitrogen. The flow rate of the gas to be circulated is not particularly limited, but from the viewpoint of the effect of preventing clogging of the liquid addition nozzle, it is preferably 0.1 Nm ³ / h or more, more preferably 0.2 Nm ³ / h or more, and further preferably 0.5 Nm ³ / h or more, from the viewpoint of cost, preferably not more than 15 Nm ³ / h, more preferably 12Nm ³ / h, more preferably not more than 10 Nm ³ / h.

The cleaning method of the present invention can be used for cleaning the mixer used for producing various products, and is particularly suitable for cleaning the mixer used for producing a cellulose derivative. Hydroxyalkyl cellulose or a derivative thereof is preferable as the cellulose derivative, and cationized hydroxyalkyl cellulose is more preferable, from the viewpoint that the excellent cleaning effect of the present invention can be effectively exhibited because it easily adheres to the wall surface in the mixer or the stirring shaft. , Catified hydroxypropyl cellulose is more preferred.

[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 (A) and (B), and then performs the steps (I) to (III). The method.
Step (A): A step of reacting a cellulose-containing raw material and a reactant in a mechanical stirring mixer in the presence of a basic catalyst to obtain a cellulose derivative Step (B): A step of obtaining a cellulose derivative obtained in step (A). Step of discharging from the mixer

<Cellulose derivative>
As the cellulose derivative obtained by the production method of the present invention, hydroxyalkyl cellulose or a derivative thereof is preferable, and cationized hydroxyalkyl cellulose is preferable from the viewpoint of exhibiting the excellent cleaning effect of the steps (I) to (III). More preferably, cationized hydroxypropyl cellulose is even more preferable. The shape of the cellulose derivative is not particularly limited, but is, for example, powder, flakes, paste, granular or lumpy, and powder is preferable. Although the powdered cellulose derivative tends to adhere to the inside of the mechanical stirring type mixer in the manufacturing process, it is easy to exert the cleaning effect by the steps (I) to (III) and can be effectively washed.
Hereinafter, a method for producing powdered cationized hydroxyalkyl cellulose as a cellulose derivative will be described as an example, but the production method of the present invention is not limited to this aspect.

<Process (A)>
The step (A) is a step of reacting the cellulose-containing raw material and the reactant in the mechanical stirring type mixer in the presence of a basic catalyst to obtain a cellulose derivative.
In the step (A), the mechanical stirring type mixer described in the cleaning method of the present invention is used. The mixer is preferably equipped with a liquid addition nozzle.

(Cellulose-containing raw material)
Cellulose-containing raw materials used in step (A) include chemically pure cellulose, various wood chips, pruned branches of various trees, thinned wood, branch wood, construction waste, factory waste, and other wood; from wood. Pulps such as wood pulp produced 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 stems; Various cellulose-containing raw materials such as paddy husks, palm husks, coconut husks and other plant husks can be used. Among these, pulps are preferable.

From the viewpoint of reactivity with the reactant, the cellulose-containing raw material used in the step (A) is preferably in the form of powder (hereinafter, the powdered cellulose-containing raw material is also referred to as "powdered cellulose").
Examples of the method for obtaining powdered cellulose include a method in which a cellulose-containing raw material is cut and dried as required, and then pulverized by a pulverizer. In the pulverization treatment, the cellulose-containing raw material can be made smaller in diameter and crystallized, so that the reactivity with the reactant is further improved. The method of cutting, drying, and pulverizing the cellulose-containing raw material is not particularly limited, and a known method can be used.

The powdery cellulose used in the step (A) has a volume median particle diameter (D50) of preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more. From the viewpoint of reaction uniformity with the reactant, D50 is preferably 300 μm or less, more preferably 200 μm or less, still more preferably 100 μm or less.

The crystallization index of the powdered cellulose used in the step (A) is preferably 25% or less, more preferably 20% or less, further preferably 15% or less, still more preferably 10% or less, and from the viewpoint of productivity. Is preferably -10% or more. In particular, when the crystallization index of powdered cellulose is 10% or less, the reactivity with the reactant and the reaction uniformity are improved.
The cellulose crystallization index refers to the cellulose crystallization index derived from the type I crystal structure of cellulose, and is obtained by the following formula (1) from the results of X-ray crystal diffraction measurement. The lower the value of the crystallization index, the lower the crystallinity of cellulose.
Crystallization index (%) = [(I _22.6- I _18.5 ) / I _22.6 ] x 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 °). ]

The water content of the powdered cellulose is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and from the viewpoint of reactivity with the reactants, It is preferably 10% by mass or less, more preferably 7.0% by mass or less, still more preferably 4.0% by mass or less, still more preferably 3.0% by mass or less.
The D50, the crystallization index, and the water content can be specifically measured by the method described in Examples.

(Reactant)
In the present invention, the reactant refers to a compound capable of introducing a substituent by reacting with a primary or secondary hydroxyl group of cellulose. When cationized hydroxyalkyl cellulose is produced as a cellulose derivative, a hydroxyalkylating agent and a cationizing agent are used as the reactants.

[Hydroxyalkylating agent]
Specific examples of the hydroxyalkylating agent include epoxy alkanes, alkyl glycidyl ethers, alkyl halohydrin 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 propylene oxide and butylene oxide is preferable, and propylene oxide is more preferable.

[Cationizing agent]
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. These cationizing agents can be used alone or in combination of two or more.
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.

(Basic catalyst)
Examples of the basic catalyst used in the step (A) 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 trimethylamine. Examples thereof include tertiary amines such as triethylamine. Among these, one or more selected from the group consisting of alkali metal hydroxide and alkaline earth metal hydroxide is preferable, alkali metal hydroxide is more preferable, and selected from the group consisting of sodium hydroxide and potassium hydroxide. One or more of them are more preferable, and sodium hydroxide is even more preferable.

The amount of the basic catalyst used in the step (A) is an anhydroglucose unit of cellulose (hereinafter, "AGU") constituting the main chain of the cellulose-containing raw material from the viewpoint of efficiently advancing the reaction between the cellulose-containing raw material and the reactant. It is preferably 0.5 molar equivalent or more, more preferably 0.7 molar equivalent or more, still more preferably 0.8 molar equivalent or more with respect to 1 mol. On the other hand, from the viewpoint of cost, the amount of the basic catalyst used is preferably 3.0 molar equivalents or less, more preferably 2.5 molar equivalents or less, still more preferably 2.0 molar equivalents, relative to 1 mol of the cellulose-containing raw material AGU. It is less than or equal to a molar equivalent, more preferably less than or equal to 1.5 molar equivalents.

(reaction)
In the step (A), the cellulose-containing raw material and the reactant are reacted in a mechanical stirring type mixer in the presence of the basic catalyst.
In the case of producing cationized hydroxyalkyl cellulose, the reaction order of the hydroxyalkylating agent and the cationizing agent used as a reactant is not particularly limited, but the cellulose-containing raw material is reacted with the hydroxyalkylating agent in the presence of a basic catalyst. It is preferable to produce hydroxyalkyl cellulose and then react the hydroxyalkyl cellulose with a cationizing agent.

[Hydroxyalkylation step]
In the reaction of the step (A), first, in the presence of a basic catalyst, the cellulose-containing raw material and the hydroxyalkylating agent are reacted in a mechanical stirring type mixer to obtain hydroxyalkyl cellulose (hydroxyalkylation step).
The order of adding the basic catalyst and the hydroxyalkylating agent is not particularly limited, but it is preferable that the cellulose-containing raw material and the basic catalyst are mixed and then the hydroxyalkylating agent is added for the reaction. This is because the alkali cellulose having high reaction activity is produced by mixing the cellulose-containing raw material and the basic catalyst, so that the subsequent reaction with the hydroxyalkylating agent proceeds efficiently.

The above reaction is preferably carried out in a solid phase state. By carrying out the above reaction in a solid phase state, the reaction between the cellulose-containing raw material and the hydroxyalkylating agent proceeds efficiently. Further, for example, if a large excess of water is present in the reaction system of the hydroxyalkylation step, a hydration reaction (side reaction) of the epoxy alkane occurs when a hydroxyalkylating agent such as an epoxy alkane is used, which is a by-product. Is likely to occur and the yield is likely to decrease. Therefore, by carrying out the reaction 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 hydroxyalkylation step is preferably more than 0% by mass with respect to the cellulose in the cellulose-containing raw material from the viewpoint of uniformly dispersing the basic catalyst and the hydroxyalkylating agent in the cellulose-containing raw material. Yes, more preferably 2.0% by mass or more, still more preferably 5.0% by mass or more, still more preferably 10% by mass or more, still more preferably 15% by mass or more. From the viewpoint of suppressing the side reaction and improving the yield, the content is preferably 100% by mass or less, more preferably 85% by mass or less, still more preferably 70% by mass or less, still more preferably 55% by mass or less. is there. In the present invention, if the water content during the reaction is 100% by mass or less, the reaction is in a solid phase state.
The amount of cellulose in the cellulose-containing raw material means a value obtained by subtracting the amount of water in the cellulose-containing raw material from the mass of the cellulose-containing raw material. The water content during the reaction in the hydroxyalkylation step means the sum of the water content in the cellulose-containing raw material provided in the step and the amount of water added as needed in the step.
For example, in the hydroxyalkylation step, first, a cellulose-containing raw material, a basic catalyst, and water if necessary are added and mixed in a mixer, and the mixture is stirred. When water is added, the amount of water added during the reaction is preferably adjusted to be within the above range. As a result, the above-mentioned alkaline cellulose is produced.
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.

As a method of adding the basic catalyst into the mixer, from the viewpoint of uniformly dispersing the basic catalyst in the cellulose-containing raw material, the basic catalyst or a solution thereof is charged into the mixer using the liquid addition nozzle. Is preferable. The method of adding the basic catalyst or its solution is not particularly limited and may be flowed down, dropped or sprayed, but it is preferable to add the basic catalyst by spraying from the viewpoint of uniformly dispersing the basic catalyst in the cellulose-containing raw material. .. If the basic catalyst is a liquid, it may be added as it is. If the basic catalyst is a solid, a solution dissolved in a solvent in which the basic catalyst can be dissolved is prepared and added. The solvent used is not particularly limited as long as the basic catalyst can be dissolved.
When the basic catalyst is one or more selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides, it is preferable to spray an aqueous solution of the catalyst. The concentration of the basic catalyst solution is not particularly limited as much as possible, but is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 45% by mass from the viewpoint of suppressing clogging of the liquid addition nozzle. % Or less, more preferably 35% by mass or less.

After the addition of the basic catalyst or its solution is completed, it is preferable to flow the gas through the liquid addition nozzle from the viewpoint of preventing the liquid addition nozzle from being blocked. The gas to be circulated is preferably an inert gas such as nitrogen or argon, and more preferably nitrogen.
The flow rate of the gas to be circulated is not particularly limited, but from the viewpoint of the effect of preventing clogging of the liquid addition nozzle, it is preferably 0.1 Nm ³ / h or more, more preferably 0.2 Nm ³ / h or more, and further preferably 0.5 Nm ³ / h or more, from the viewpoint of cost, preferably not more than 15 Nm ³ / h, more preferably 12Nm ³ / h, more preferably not more than 10 Nm ³ / h. The above flow rate is the flow rate of the gas to be circulated per nozzle.
The time for flowing the gas through the liquid addition nozzle is not particularly limited, but is preferably 1 minute or more and 10 minutes or less.

Next, the above-mentioned hydroxyalkylating agent is added to the mixture obtained by the above method (mixture containing alkaline cellulose) and reacted with the hydroxyalkylating agent. The method of adding the hydroxyalkylating agent is not particularly limited, and batch addition, divisional addition, continuous addition, or a combination of these may be used.
The amount of the hydroxyalkylating agent used is not limited, and may be appropriately adjusted according to the desired amount of hydroxyalkyl group introduced. For example, it is preferably 0.50 mol or more, more preferably 1.0 mol or more, and further preferably 3.0 mol or more per 1 mol of AGU of cellulose in the cellulose-containing raw material used in the step (A). 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 10 mol or less, per 1 mol of AGU of cellulose in the cellulose-containing raw material used in the step (A). It is 8.0 mol or less, more preferably 6.0 mol or less, still more preferably 5.0 mol or less.

From the viewpoint of improving the reaction rate and the reaction uniformity, the peripheral speed of stirring during the reaction in the hydroxyalkylation step is preferably 0.2 m / sec or more, more preferably 0.5 m / sec or more, still more preferably 1. It is 0 m / sec or more, more preferably 1.5 m / sec or more, even more preferably 2.0 m / sec or more, and from the viewpoint of energy efficiency, preferably 10 m / sec or less, more preferably 9.0 m or more. It is less than / sec., More preferably 8.0 m / sec or less, still more preferably 7.0 m / sec or less, still more preferably 5.0 m / sec or less.
When the mixer has a chopper blade, the stirring rotation speed of the chopper blade is preferably 1.0 m / sec or more, more preferably 2.0 m / sec or more, from the viewpoint of improving the reaction rate and the reaction uniformity. It is more preferably 5.0 m / sec or more, and from the viewpoint of energy efficiency, it is preferably 40 m / sec or less, more preferably 30 m / sec or less, still more preferably 20 m / sec or less.

The reaction temperature and reaction time in the hydroxyalkylation step are not particularly limited, but from the viewpoint of improving the reaction rate, the reaction temperature is preferably 0 ° C. or higher, more preferably 20 ° C. or higher, still more preferably 25 ° C. or higher. Further, from the viewpoint of the stability of the cellulose-containing raw material or hydroxyalkyl cellulose, the temperature is preferably 100 ° C. or lower, more preferably 80 ° C. or lower.
The reaction time is preferably 0.1 hour or more, more preferably 0.3 hours or more from the viewpoint of reaction yield, and preferably 48 hours or less, more preferably 24 hours or less from the viewpoint of productivity. .. The reaction time in the hydroxyalkylation step means the elapsed time from the start of addition of the hydroxyalkylating agent to the end of the reaction.

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.

The above hydroxyalkylation step is carried out to obtain hydroxyalkyl cellulose. When powdered cellulose is used as a cellulose-containing raw material and the hydroxyalkylation reaction is carried out in a solid phase state, powdered hydroxypropyl cellulose can be obtained.

[Cationization step]
Next, the hydroxyalkyl cellulose obtained as described above is reacted with a cationizing agent to obtain cationized hydroxyalkyl cellulose (cationization step). The cationization step can be carried out in the same mixer following the hydroxyalkylation step.

In the cationization step, from the viewpoint of reaction uniformity, the cationizing agent or its solution is poured into the mixer using a liquid addition nozzle to react while stirring the powdered hydroxyalkyl cellulose in the mixer. Is preferable. The charging method is not particularly limited and may be flow-down, dropping, or spraying, but from the viewpoint of reaction uniformity, charging is preferably performed by spraying. In the present invention, the "cationizing agent or its solution" is 25 ° C. Means a liquid cationizing agent alone or a solution in which the cationizing agent is dissolved in a solvent. The solvent is not particularly limited as long as it is a solvent in which the cationizing agent dissolves, and may be water, an organic solvent, or a mixture thereof. The concentration of the cationizing agent solution is not particularly limited as long as it can be added to powdered hydroxyalkyl cellulose by spraying or the like using a liquid addition nozzle, but the effective amount is preferably 50% by mass or more, more preferably 50% by mass or more. It is 65% by mass 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.
The amount of the cationizing agent used is preferably 0.001 mol or more, more preferably 0.01 mol or more, still more preferably 0.10 mol, per 1 mol of AGU of cellulose in the cellulose-containing raw material used in the step (A). The above is even 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, per 1 mol of AGU of cellulose in the cellulose-containing raw material used in the step (A). It is still more preferably 2.0 mol or less, still more preferably 1.5 mol or less, still more preferably 1.0 mol or less, still more preferably 0.80 mol or less.

From the viewpoint of preventing the liquid addition nozzle from being clogged after the addition of the cationizing agent or the solution thereof is completed, it is preferable to flow the gas through the liquid addition nozzle. The type, flow rate, and distribution time of the gas to be distributed are the same as described above.

The peripheral speed of stirring in the cationization step and its preferable range are the same as those in the hydroxyalkylation step. Further, when the mixer has a chopper blade, the stirring rotation speed of the chopper blade and its preferable range are also the same as those in the hydroxyalkylation step.

The cationization step is carried out in the presence of a basic catalyst from the viewpoint of improving the reaction rate between the hydroxyalkyl cellulose and the cationizing agent. Examples of the basic catalyst include the same compounds as described above, and it is preferable to use the basic catalyst used in the hydroxyalkylation step as it is.

The reaction temperature in the cationization step is not particularly limited, but from the viewpoint of the stability of hydroxyalkyl cellulose, it is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, still more preferably 70 ° C. or lower, and the reaction rate. From the viewpoint of improvement, it is preferably 40 ° C. or higher, more preferably 45 ° C. or higher.
The reaction time in the cationization step is not particularly limited, but from the viewpoint of yield, it is preferably 0.1 hour or more, more preferably 0.3 hours or more, still more preferably 0.5 hours or more, and also. From the viewpoint of productivity, it is preferably 6 hours or less, more preferably 4 hours or less, still more preferably 3 hours or less.

After completion of the reaction, cationized hydroxyalkyl cellulose can be isolated by performing purification operations such as neutralization of a basic catalyst, washing with hydrous isopropanol, hydrous acetone solvent and the like, if necessary.

<Process (B)>
The step (B) is a step of discharging the cellulose derivative obtained in the step (A) from the mixer. The method for discharging the cellulose derivative is not particularly limited, and a known method can be used.

<Step (I) -Step (III)>
The production method of the present invention has the above-mentioned steps (A) and (B), and then the above-mentioned steps (I) to (III) are performed. Steps (I) to (III), and preferred embodiments thereof, are as described in the cleaning method of the present invention.

The shape of the cellulose derivative obtained by the production method of the present invention is not particularly limited, but it is effectively applied to powders, flakes, pastes, granules, and lumps in which adhered substances remain in the mechanical stirring type mixer. Can be done.
In addition to hair shampoos, the cellulose derivatives obtained by the production method of the present invention can be used in a wide range of fields such as compounding components of hair cosmetic compositions such as rinses, treatments and conditioners, dispersants, modifiers and flocculants. can do.

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 (“MOC-120H” manufactured by Shimadzu Corporation). 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 0.05% or less was defined as the end point of the measurement. The measured water content was converted to mass% with respect to cellulose and used as 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 sample for measurement 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) Adhesion amount of cellulose derivative in the mixer The adhesion amount of the cellulose derivative in the mixer is the total weight of the raw material of the cellulose derivative put into the mixer and the amount of the cellulose derivative discharged in the step (B) described later. It was the difference between. In Table 1, the amount of adhesion (kg) per ^{unit capacity (m 3) of the mixer is shown.}

Production Example 1 (Production of powdered cellulose)
(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, the discharge powder temperature was 50 ° C., 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: (112L, 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 20.0 kg / h under the conditions of a continuous vibration mill having a frequency of 16.7 Hz and an amplitude of 13.4 mm.
(4) Cellulose particle size reduction treatment The coarsely pulverized cellulose obtained by the coarse pulverization treatment of (3) above is pulverized using a high-speed rotary pulverizer (manufactured by Dalton Co., Ltd., 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, and coarsely crushed cellulose is supplied from the raw material supply unit at the same supply speed as the coarse crushing process, and powder is supplied from the discharge port. Cellulose was recovered. The water content of the obtained powdered cellulose was 2.5% by mass, the crystallization index was -4.2%, and the volume median particle diameter (D50) was 70 μm.
The processes (1) to (4) were continuously carried out.

Example 1
(Production of cationized hydroxypropyl cellulose)
<Step (A-1): Hydroxypropylation step>
The powdered cellulose obtained in Production Example 1 was put into a horizontal axis rotating mechanical stirring mixer having a main wing and a chopper wing inside a reaction tank with a jacket and equipped with a spray nozzle. 100 parts by mass was charged. After replacing the gas phase part in the tank with nitrogen, 24.7 parts by mass of sodium hydroxide (AGU 1 mol of powdered cellulose), which is a basic catalyst, was stirred under a stirring of a main blade peripheral speed of 3 m / s and a chopper blade of 16 m / s. The aqueous sodium hydroxide solution obtained by mixing 1.0 molar equivalent of water with water was sprayed and charged through a spray nozzle. 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 50 parts by mass as the amount of water in the reaction system. After the spraying of the sodium hydroxide aqueous solution was completed, nitrogen was circulated through the spray nozzle at 7 Nm ³ / h for 3 minutes. The amount of nitrogen distributed in this embodiment is the amount of nitrogen distributed per spray nozzle. Further, the internal temperature was adjusted to 50 ° C. ± 5 ° C. with jacket warm water, and mixing was continued for 2 hours. Next, under stirring at a main wing peripheral speed of 4.4 m / s and a chopper blade of 16 m / s, 143.3 parts by mass of propylene oxide (PO) (of powdered cellulose) was adjusted while adjusting the internal temperature to 45 ° C. ± 5 ° C. 4.0 mol per 1 mol of AGU) was added over about 8 hours so as to maintain an internal pressure of 0.07 to 0.10 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 to obtain powdered hydroxypropyl cellulose.

<Step (A-2): Catification step>
In the same reaction tank as in step (A-1), while continuing stirring, 3-chloro-2-hydroxy, which is a cationizing agent, is applied to the powdered hydroxypropyl cellulose obtained in step (A-1). 70% by mass aqueous solution of propyltrimethylammonium chloride (HAC) (water content 30%, purity 90% or more, manufactured by Yokkaichi Chemical Co., Ltd., product name "CTA-65") 112.7 parts by mass (AGU 1 mol of powdered cellulose) On the other hand, 0.68 mol) as HAC was spray-injected with a spray nozzle. After the spraying of the HAC aqueous solution was completed, nitrogen was circulated through the spray nozzle at 7 Nm ³ / h for 3 minutes. Then, stirring was continued for 2 hours while adjusting the internal temperature to 50 ° C. ± 5 ° C. Subsequently, the mixture was cooled to an internal temperature of 40 ° C. to obtain powdered cationized hydroxypropyl cellulose as a cellulose derivative. The total amount charged was 174 kg per ^{unit capacity (m 3) of the mixer.}

<Process (B)>
The cationized hydroxypropyl cellulose obtained in step (A-2) was discharged from the bottom exhaust valve of the mixer. In the early stage of discharge, the peripheral speed of the main wing was 0.8 m / s, and in the latter stage of discharge, the peripheral speed of the main wing was 3.9 m / s. At the time of discharge, the chopper blade was intermittently stirred at 1.6 m / s. After discharge, the amount of cationized hydroxypropyl cellulose adhered in the mixer was 0.02 kg per ^{unit volume (m 3) of the mixer of the mixer.}

(Washing)
After the step (B), the pressure in the mixer was reduced to 11 kPa (absolute pressure) (step (I-1)).
Next, 0.5 m ^{3 of water was charged per unit capacity (m 3} ) of the mixer as a cleaning liquid to raise the temperature of the jacket hot water to 80 ° C., and the main wing peripheral speed was 7.8 m / s and the chopper blade peripheral speed was 7.1 m. The mixture was stirred at / s for 3 hours (step II-1a). The final temperature reached of the cleaning liquid was 73 ° C. Further, the stirring direction of the main wing was reversed, and the main wing was stirred at a peripheral speed of 7.8 m / s and a chopper blade at a peripheral speed of 7.1 m / s for 0.5 hours (step II-1b). After the completion of step II-1b, the pressure in the mixer was increased to atmospheric pressure by introducing nitrogen, and then the washing water was discharged (step (III-1)). No bubbling of the discharged wash water was observed.
The pressure inside the mixer is reduced to 41 kPa (absolute pressure) (step (I-2)), and 0.5 m ^{3 of water is charged per unit capacity (m 3} ) of the mixer as a cleaning liquid to bring the jacket hot water to 80 ° C. The temperature was raised, and the mixture was stirred at a main blade peripheral speed of 6.2 m / s and a chopper blade peripheral speed of 7.1 m / s for 2 hours (step II-2a). Further, the stirring direction of the main wing was reversed, and the main wing was stirred at a peripheral speed of 6.2 m / s and a chopper blade at a peripheral speed of 7.1 m / s for 0.5 hours (step II-2b). After the completion of step II-2b, the pressure in the mixer was adjusted to atmospheric pressure, and then the washing water was discharged (step (III-2)).
When the inside of the mixer was visually observed after the completion of the step (III-2), no deposit (cationized hydroxypropyl cellulose) remained. In addition, no bubbling of the discharged washing water was observed.

After step (III-2), vacuum drying was performed in the mixer. The vacuum drying was carried out for 2 hours while raising the temperature of the jacket warm water to 80 ° C., reducing the pressure in the mixer to 2 kPa (absolute pressure), ^{and circulating nitrogen at 7 Nm 3 / h through the spray nozzle.}
After drying under reduced pressure, it was confirmed whether or not the spray nozzle was blocked, and it was confirmed that no blockage had occurred.

Example 2
Hydroxy cationized in the same manner as in Example 1 except that the amount of propylene oxide (PO) used was changed to 150.5 parts by mass (4.2 mol with respect to 1 mol of AGU of powdered cellulose) in Example 1. Propylene cellulose was produced.
In addition, the mixer was washed in the same manner as in Example 1 except that the conditions of each step were changed as shown in Table 1. The results are shown in Table 1.

Comparative Example 1
Catified hydroxypropyl cellulose was produced in the same manner as in Example 1. After that, the mixer was washed in the same manner as in Example 1 except that the conditions of each step were changed as shown in Table 1. The results are shown in Table 1.

As is clear from Table 1, in Comparative Example 1 in which the pressure inside the mixer was not reduced to 80 kPa or less before the cleaning liquid was charged in the cleaning of the mechanical stirring type mixer, deposits remained in the mixer even after cleaning and were discharged. Foaming was also seen in the washed water. Further, in Comparative Example 1, since the gas was not passed through the spray nozzle during vacuum drying after the completion of the steps (I) to (III), the spray nozzle was blocked.
On the other hand, in the cleaning method of the embodiment of the present application, no residual deposits after cleaning, no bubbling of discharged cleaning water, and no clogging of the spray nozzle was observed.

According to the present invention, the mechanical stirring type mixer used for producing cellulose derivatives and the like can be effectively cleaned by a simple operation, so that contamination due to poor cleaning of the mixer can be prevented even in large-scale production. The product can be manufactured without occurring.

10 Mechanical stirring mixer 11 Reaction tank 12 Stirring blade (main blade)
12a Rotating shaft of stirring blade 20 Liquid addition nozzle

Claims (9)

A method for cleaning a mechanically agitated mixer used for producing a cellulose derivative. The cleaning method is a step (A): in the presence of a basic catalyst, a cellulose-containing raw material and a reactant are reacted in a mechanically agitated mixer. To obtain a cellulose derivative, and
Step (B): A step of discharging the cellulose derivative obtained in the step (A) from the mixer.
To produce a cellulose derivative in a way that closed and then performs the following steps (I) ~ step (III), a method of washing mechanical stirring type mixer.
Step (I): Step of reducing the pressure in the mixer to 80 kPa or less Step (II): Step of introducing a cleaning liquid into the mixer after step (I) and stirring under a reduced pressure of 80 kPa or less Step (III) : A step of setting the pressure in the mixer to atmospheric pressure after the step (II) and then discharging the cleaning liquid. The cleaning method according to claim 1 , wherein the cleaning liquid is water. The cleaning method according to claim 1 or 2 , wherein the stirring temperature in the step (II) is 40 ° C. or higher. Any one of claims 1 to 3 , wherein the mixer is provided with a liquid addition nozzle, and in the step (A), the basic catalyst or a solution thereof is charged into the mixer using the liquid addition nozzle. The cleaning method described in. The cleaning method according to any one of claims 1 to 4 , wherein the inside of the mixer is dried under reduced pressure after the step (III). The cleaning method according to claim 5 , wherein the mixer is provided with a liquid addition nozzle, and after the step (III), the inside of the mixer is dried under reduced pressure while flowing gas through the liquid addition nozzle. The cleaning method according to any one of claims 1 to 6 , wherein the basic catalyst is at least one selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides. The washing method according to any one of claims 1 to 7 , wherein the cellulose derivative is cationized hydroxypropyl cellulose. The washing method according to any one of claims 1 to 8, wherein the cellulose derivative obtained in the step (A) is powder, flakes, paste, granular, or lumpy.