JP6776111B2 - Cellulose nanofiber manufacturing equipment and cellulose nanofiber manufacturing method - Google Patents

Description

The present invention relates to an apparatus for producing cellulose nanofibers and a method for producing cellulose nanofibers.

In recent years, nanotechnology has been attracting attention for the purpose of refining substances to the nanometer level and obtaining new physical properties different from the conventional properties of substances. Cellulose nanofibers produced from cellulosic raw materials such as pulp fibers are excellent in strength, elasticity, thermal stability, etc., and therefore are filled with filter media, filter aids, ion exchanger base materials, and chromatography analysis equipment. It is used for industrial purposes such as a filler for blending materials, resins and rubbers, and as a blending agent for cosmetics such as lipsticks, powder cosmetics and emulsified cosmetics. In addition, since cellulose nanofibers have excellent water-based dispersibility, they are viscosity-retaining agents for foods, cosmetics, paints, etc., fortifiers for food raw material fabrics, water-retaining agents, food stabilizers, low-calorie additives, and emulsification. It is expected to be used in many applications such as stabilizing aids.

When producing cellulose nanofibers, it is common to defibrate pulp or the like in an aqueous-dispersed state by mechanical treatment (see JP-A-2010-235679).

JP-A-2010-235679

However, when cellulose nanofibers are produced by mechanical treatment, the pulp fibers in a slurry in which pulp or the like is dispersed in water need to be mechanically treated a plurality of times. When the mechanical treatment is performed, the cellulose fibers are refined as the number of mechanical treatments is repeated, and the viscosity of the cellulose fiber slurry becomes high, so that the fluidity becomes very poor. For this reason, the slurry tends to adhere to the wall surface in the pipe, and a part of the slurry tends to remain on the wall surface of the pipe even after being discharged, which may cause clogging or contamination of the pipe. Further, in a general welded pipe, foreign matter generated during welding of the pipe may remain and be mixed in the slurry. Therefore, in order to improve the productivity of cellulose nanofibers, it is required to suppress the occurrence of clogging and contamination of pipes.

The present invention has been made based on the above circumstances, and an object of the present invention is an apparatus for producing cellulose nanofibers and a cellulose capable of efficiently producing cellulose nanofibers by suppressing clogging and contamination of pipes. It is to provide a method for producing nanofibers.

In the production of cellulose nanofibers, the inventors have used a specific pipe as a pipe for inflowing and outflowing a cellulose fiber slurry whose viscosity increases as the number of mechanical treatments of pulp or the like in an aqueous dispersion state is repeated. , It has been found that the productivity of cellulose nanofibers can be improved, and the present invention has been completed.

That is, the invention made to solve the above problems is an apparatus for producing cellulose nanofibers for refining pulp fibers in a slurry, a high-pressure homogenizer for refining pulp fibers in the slurry, and the above. A tank for storing a slurry in which pulp fibers have been refined using a high-pressure homogenizer and a pipe connected to the high-pressure homogenizer and the tank are provided, and the pipes are connected via a joint fitted with a gasket. It is a manufacturing device for cellulose nanofibers, which is a sanitary pipe.

In the cellulose nanofiber manufacturing apparatus, in the production of cellulose nanofibers that require a large number of mechanical treatments for pulp or the like in an aqueous dispersion state, the cellulose fiber slurry becomes more viscous as the number of mechanical treatments is repeated. The pipes that flow in and out of the pipe are sanitary pipes that are connected via a joint fitted with a gasket. As a result, even if a slurry of cellulose fibers having a very high viscosity and a reduced fluidity and easily adhering to the wall surface flows in and out through the pipe, the pipe has a seamless structure and is uneven. Since it has no inner wall surface, it is possible to improve the possibility that the piping is easily clogged, and the highly viscous slurry can be stably transferred. Further, unlike a welded pipe, it is possible to eliminate the possibility that foreign matter generated during welding remains and is mixed in the slurry. Therefore, cellulose nanofibers can be efficiently produced.

It is preferable that the gasket is made of a fluororesin. By doing so, since the gasket has good alkali resistance, heat resistance and acid resistance, the durability of the gasket can be improved.

The inner surface of the pipe may be buffed, for example. The surface roughness (Ra) of the inner surface of the pipe is preferably 1.5 μm or less. The surface roughness (Ra) of the inner surface of the pipe is more preferably 1.3 μm or less, and further preferably 1.1 μm or less. By doing so, it is difficult for the slurry to adhere to the wall surface in the above pipe, and it is difficult for a part of the slurry to remain on the wall surface of the pipe even after being discharged, so that the pipe is less likely to be clogged or contaminated. Become.

The cellulose nanofiber manufacturing apparatus finely processes pulp fibers in a slurry having a solid content concentration of 0.1% by mass or more and 8.0% by mass or less. By setting the solid content concentration of the slurry containing the pulp fibers to be refined within the above range, it is possible to suppress the occurrence of clogging of the piping due to the excessive increase in the viscosity of the slurry, and to make the cellulose nanos more efficient. Fiber can be manufactured. Here, the solid content concentration means a component other than the solvent.

Another invention made to solve the above problems is a step of refining the pulp fibers in the slurry using a high-pressure homogenizer, and the slurry obtained by refining the pulp fibers is transferred by a sanitary pipe. This is a method for producing cellulose nanofibers, which comprises the above-mentioned steps and has a slurry solid content concentration of 0.1% by mass or more and 8.0% by mass or less. According to the cellulose nanofiber manufacturing method, by setting the solid content concentration of the slurry containing the pulp fiber to be subjected to the micronization treatment within the above range, it is possible to suppress an excessive increase in the viscosity of the slurry, and the pulp slurry. Is suitable for the viscosity, so that the slurry can be efficiently transferred by the sanitary piping, and the occurrence of clogging of pulp fibers in the piping can be suppressed. Therefore, cellulose nanofibers can be produced more efficiently. Here, the solid content concentration means a component other than the solvent.

The "cellulose nanofiber" refers to a fine cellulose fiber obtained by defibrating a pulp fiber, and generally refers to a cellulose fiber containing cellulose fine fiber having a fiber width of nano size (1 nm or more and 1000 nm or less). ..

According to the cellulose nanofiber manufacturing apparatus and the cellulose nanofiber manufacturing method of the present invention, it is possible to efficiently manufacture cellulose nanofibers by suppressing the occurrence of clogging and contamination of pipes.

It is the schematic of the manufacturing apparatus of the cellulose nanofiber which concerns on one Embodiment of this invention. It is the schematic sectional drawing of the ferrule type joint which concerns on one Embodiment of this invention. It is the schematic sectional drawing of the screw type joint which concerns on one Embodiment of this invention. It is a partial schematic diagram of the opposed collision type high pressure homogenizer.

Hereinafter, the cellulose nanofiber manufacturing apparatus and the cellulose nanofiber manufacturing method according to the embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[Cellulose nanofiber manufacturing equipment]
The cellulose nanofiber manufacturing apparatus 1 of FIG. 1 is an apparatus for refining pulp fibers in a slurry in which pulp fibers are dispersed in water. The cellulose nanofiber manufacturing apparatus 1 includes a tank 10 and a tank 20 for storing the slurry, a high-pressure homogenizer 5 for purifying the pulp fibers in the slurry, a pipe 6 connected to the bottom of the tank 10, and the tank 20. The pipe 9 is connected to the bottom of the pipe, the pipe 12 is connected to the high-pressure homogenizer 5, and the pump 13 and the pipe 31 for transferring the manufactured cellulose nanofibers to a storage tank such as a container (not shown) are provided. Further, a high-pressure pump 14 for transferring the slurry via the high-pressure homogenizer 5 and three-way valve 15, two-way valve 25, two-way valve 27, two-way valve 16, three-way valve 17, and three-way valve 18 which are opening / closing means. A two-way valve 30, a pipe 7, a pipe 23, a pipe 33, a pipe 36, a pipe 24, a pipe 35, a pipe 8, a pipe 19, a pipe 34, a pipe 22 and a pipe 32 are provided.

Pipe 6, pipe 9, pipe 12, pipe 31, pipe 7, pipe 23, pipe 33, pipe 36, pipe 24, pipe 35, pipe 8, pipe 19, pipe 34, pipe 22 and pipe 32 are fitted with gaskets. It is a sanitary pipe connected via a joint. Since the pipe is a sanitary pipe, the pipe has a seamless structure even if a slurry of cellulose fibers having a very high viscosity and a low fluidity and easily adhering to the wall surface flows in and out. Since it has an inner wall surface having no unevenness, it is possible to improve the possibility that the piping is easily clogged, and the highly viscous slurry can be stably transferred. Further, unlike a welded pipe, it is possible to eliminate the possibility that foreign matter generated during welding remains and is mixed in the slurry. Therefore, cellulose nanofibers can be efficiently produced.

As the material of the pipe, stainless steels such as SUS304 and SUS316L are used. Further, since the surface and inner surface of the pipe are polished, the slurry adhering to the surface and inner surface of the pipe can be easily cleaned.

As the pipe, a ferrule type joint or a screw type joint that can be easily attached and detached is used as the pipe joint. Since the pipe can be easily attached and detached, the pipe itself can be removed and the pipe can be efficiently cleaned. FIG. 2 is a schematic cross-sectional view of the ferrule type joint 50. FIG. 3 is a schematic cross-sectional view of the screw type joint 60. As shown in FIG. 2, the ferrule type joint 40 is composed of a ferrule 41, a ferrule 42, a clamp 44, a clamp 45, and a ferrule gasket 43. Since the ferrule type joint 40 does not have irregularities on the inner surface, it is possible to prevent the slurry from remaining in the joint. Further, as shown in FIG. 3, the screw type joint 60 is composed of a screw sleeve 61, a screw liner 62, a hexagon nut 63, a hexagon nut 64, and an L-shaped gasket 65. The screw type joint 60 has excellent durability against repeated attachment / detachment.

The ferrule gasket 43 and the L-shaped gasket 65 are used for maintaining the sealing property. As the material of these gaskets (packing), a fluororesin is preferable from the viewpoint of durability. Examples of the fluororesin include PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), and ETFE (tetrafluoroethylene / (Ethylene copolymer), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), ECTFE (chlorotrifluoroethylene / ethylene copolymer), etc., among which more alkali resistance, heat resistance and acid resistance Polytetrafluoroethylene having excellent properties is preferable.

The inner diameters of the above pipe 6, pipe 9, pipe 12, pipe 31, pipe 7, pipe 23, pipe 33, pipe 36, pipe 24, pipe 35, pipe 8, pipe 19, pipe 34, pipe 22 and pipe 32 are It is preferably 35 mm or more and 100 mm or less. By setting the inner diameter of the pipe within the above range, the pressure and flow rate of the highly viscous slurry can be appropriately controlled, and the occurrence of clogging of pulp fibers can be suppressed.

The slurry is stored in the tank 10 and the tank 20. The tank 10 is provided with a charging port 11 for charging raw materials such as a slurry in which pulp fibers are dispersed in water, and a stirrer 4 for mixing the charged raw materials. Further, the tank 20 is provided with a charging port 21 and a stirrer 39.

A pipe 6 for flowing in and out of the slurry is connected to the bottom of the tank 10. The pipe 6 is connected to the pipe 7, and the pipe 7 is connected to the pipe 23 together with the installation of the three-way valve 15. A three-way valve 18 and a two-way valve 25 are installed in the pipe 23. The pipe 23 is connected to the pipe 33 via the two-way valve 25, and is connected to the pipe 12 and the pipe 24 via the three-way valve 18. A three-way valve 18 and a two-way valve 27 are installed in the pipe 24, and the pipe 24 is connected to the pipe 35 via the two-way valve 27.

The pipe 12 is connected to the pipe 36 and is also connected to the high pressure pump 14 and the high pressure homogenizer 5. Further, the pipe 12 is connected to the pipe 22 and the pipe 19 via a three-way valve 17. A three-way valve 17 and a three-way valve 15 are installed in the pipe 22, and the pipe 22 is connected to the pipe 32 and the pipe 7 via the three-way valve 15. The pipe 19 is connected to the pipe 8, and a three-way valve 17 and a two-way valve 16 are installed, and the pipe 19 is connected to the pipe 34 via the two-way valve 16.

A pipe 9 for flowing in and out of the slurry is connected to the bottom of the tank 20. The pipe 9 is connected to the pipe 8, and the pipe 8 is connected to the pipe 19 and the pipe 24.

The flow velocity of the slurry flowing through the pipe is preferably 0.10 m / s or more and 0.40 m / s or less. By setting the flow velocity of the highly viscous slurry transferred by the sanitary piping within the above range, the slurry can be transferred more efficiently.

The high-pressure homogenizer refers to a homogenizer having an ability to discharge a slurry at a pressure of, for example, 10 MPa or more, preferably 100 MPa or more. By treating the pulp fibers with the high-pressure homogenizer 5, collisions between the pulp fibers, pressure difference, microcavitation and the like act to effectively cause defibration. As a result, the number of processes in the miniaturization process can be reduced (shortened), and the production efficiency of cellulose nanofibers can be further improved.

As the high-pressure homogenizer 5, a counter-collision type high-pressure homogenizer (microfluidizer, wet jet mill) is preferable, and in the miniaturization treatment, the slurry is preferably collided in a straight line. By doing so, the energy given by the high-pressure homogenizer can be converted into collision energy to the maximum extent, and more efficient pulp fiber defibration can be performed. Specifically, as partially shown in FIG. 4, in the high-pressure homogenizer 5, which is a counter-collision type high-pressure homogenizer, the pressurized slurry S1 and the slurry S2 are opposed to each other at the confluence X on the upstream side. The flow path 51 is formed. The slurry S1 and the slurry S2 collide with each other at the confluence X, and the collided slurry S3 flows out from the downstream flow path 52. The downstream flow path 52 is provided perpendicular to the upstream side flow path 51, and the upstream side flow path 51 and the downstream side flow path 52 form a T-shaped flow path. By using such a high-pressure homogenizer 5, the energy given by the high-pressure homogenizer 5 can be converted to collision energy to the maximum extent, and more efficient pulp fiber defibration occurs.

A pipe 12 for flowing in and out of the slurry from the high pressure homogenizer 5 is connected to the high pressure homogenizer 5. The slurry stored in the tank 10 and the tank 20 is transferred to the high pressure homogenizer 5 by the high pressure pump 14, and the slurry refined by the high pressure homogenizer 5 is transferred to the tank 10 or the tank 20 by the high pressure pump 14. ..

The cellulose nanofiber manufacturing apparatus operates the high-pressure pump 14, and is a three-way valve 15, two-way valve 25, two-way valve 27, three-way valve 17, three-way valve 18, two-way valve 30, and two-way valve, which are opening and closing means. By controlling the opening and closing of the 16th, the slurry is transferred between the tank 10 and the high pressure homogenizer 5 and between the tank 20 and the high pressure homogenizer 5.

A two-way valve 30 is installed in the pipe 36, and the pipe 36 is connected to the pipe 31 via the two-way valve 30. A pump 13 is installed in the pipe 31, and the multi-ended portion is connected to a storage tank such as a container (not shown). The cellulose nanofibers that have been miniaturized are transferred by the pump 13 to a storage tank such as a container via the pipe 31.

The cellulose nanofiber manufacturing apparatus 1 can be used by a method described later as a “cellulose nanofiber manufacturing method”. According to the cellulose nanofiber manufacturing apparatus 1, even if a slurry of cellulose fibers having a very high viscosity and a low fluidity and easily adhering to the wall surface is flowed in and out through the pipe, the pipe still has the effect. Since it has an inner wall surface without unevenness and can be easily disassembled and cleaned, it is possible to improve the possibility that the slurry remains on the wall surface of the pipe and the possibility that the pipe is easily clogged. Further, unlike a welded pipe, it is possible to eliminate the possibility that foreign matter generated during welding remains and is mixed in the slurry. Therefore, cellulose nanofibers can be efficiently produced. Therefore, cellulose nanofibers can be efficiently produced.

[Manufacturing method of cellulose nanofibers]
In the method for producing cellulose nanofibers according to an embodiment of the present invention, the pulp fibers in the slurry are refined using the above-mentioned cellulose nanofiber manufacturing apparatus 1. The method for producing the cellulose nanofiber is
(1) A step (T1) of flowing out the slurry charged into the tank 10 from the bottom of the tank 10 and transferring it to the high-pressure homogenizer 5 by a sanitary pipe.
(2) A step (T2) of miniaturizing the pulp fibers in the slurry transferred using the high-pressure homogenizer 5 and
(3) A step (T3) of transferring the miniaturized slurry from the high-pressure homogenizer 5 to the bottom of the tank 20 and flowing into the tank 20 from the bottom of the tank 20.
(4) A step (T4) of flowing into the tank 20, flowing out the stored slurry from the bottom of the tank 20 and transferring it to the high-pressure homogenizer 5 by a sanitary pipe.
(5) A step of reminiaturizing the pulp fibers in the transferred slurry with the high-pressure homogenizer 5 (T5).
And.

<Step of transferring from the first tank to the high-pressure homogenizer by sanitary piping (T1)>
In the T1 step, the slurry charged in the tank 10 flows out from the bottom of the tank 10 and is transferred to the high-pressure homogenizer 5 by a sanitary pipe. Slurry is usually pulp dispersed in water.

Examples of pulp fibers include broad-leaved kraft pulp (LKP) such as broad-leaved bleached kraft pulp (LBKP) and broad-leaved unbleached kraft pulp (LUKP), coniferous bleached kraft pulp (NBKP), coniferous unbleached kraft pulp (NUKP) and the like. Chemical pulp such as kraft pulp (NKP);
Stone Grand Pulp (SGP), Pressurized Stone Grand Pulp (PGW), Refiner Grand Pulp (RGP), Chemi Grand Pulp (CGP), Thermo Grand Pulp (TGP), Grand Pulp (GP), Thermo Mechanical Pulp (TMP), Mechanical pulp such as Chemithermo Mechanical Pulp (CTMP), Bleached Thermomechanical Pulp (BTMP);
Waste paper pulp manufactured from used tea paper, used kraft envelopes, used magazines, used newspapers, used leaflets, used office paper, used corrugated paper, used white paper, Kent used paper, imitation used paper, ground ticket used paper, used paper, etc.;
Examples thereof include deinked pulp (DIP) obtained by deinking used paper pulp. These may be used alone or in combination of a plurality of types as long as the effects of the present invention are not impaired.

The solid content concentration of the slurry is not particularly limited, but the lower limit of the solid content concentration of the slurry is preferably 0.1% by mass, more preferably 0.2% by mass. On the other hand, as the upper limit, 8.0% by mass is preferable, and 7.0% by mass is more preferable. If the solid content concentration of the slurry is less than the above lower limit, the pulp fibers may not be efficiently defibrated and the production efficiency of cellulose nanofibers may deteriorate. On the other hand, when the solid content concentration of the slurry exceeds the upper limit, the viscosity of the slurry may be excessively increased, and it may be difficult to suppress the occurrence of clogging of the piping.

The pulp fibers in the slurry are preferably pretreated before being miniaturized by the high pressure homogenizer. Pretreatment includes chemical treatment, coarse defibration, or a combination thereof. When the chemical treatment and the coarse defibration are performed, the order of the chemical treatment and the coarse defibration is not particularly limited, and any step may be performed first. By performing the pretreatment before the miniaturization treatment, the pulp fibers become flexible, preliminary defibration occurs efficiently, and the miniaturization process can be shortened, that is, the number of treatments can be reduced. ..

The chemical treatment, which is one of the pretreatments, is a step of subjecting the pulp fibers in the slurry to an oxidation treatment, a hydrolysis treatment, or a chemical treatment consisting of a combination thereof. By performing such a chemical treatment, a part of the chemical bond in the pulp fiber can be broken and the pulp fiber can be swollen.

The temperature of the pulp slurry to be subjected to the chemical treatment is preferably, for example, 40 ° C. or higher and 90 ° C. or lower. When the enzyme is used, the treatment is preferably about 40 ° C. or higher and 70 ° C. or lower.

Examples of the oxidizing agent used in the oxidation treatment include ozone, hypochlorous acid or a salt thereof, chloric acid or a salt thereof, perchloric acid or a salt thereof, persulfate or a salt thereof, and a perorganic acid. Among these, persulfates (persulfates and salts thereof) are preferable. When performing the oxidation treatment, an oxidation catalyst such as an N-oxyl compound can also be used in combination. Examples of the catalyst used in the hydrolysis treatment include acids and enzymes. Examples of the acid include sulfuric acid, persulfuric acid, hydrochloric acid and the like, but sulfuric acid and persulfuric acid are preferable. When an acid is used, the pH in the reaction vessel is preferably 3 or less, more preferably 0.5 or more and 2 or less. Examples of the enzyme include cellulase-based enzymes and hemicellulase-based enzymes, and cellulase-based enzymes are preferable. For the oxidation treatment and the hydrolysis treatment, a plurality of kinds of treatment agents may be used, or the oxidation treatment and the hydrolysis treatment may be combined. When an acid that also functions as an oxidizing agent, such as persulfuric acid, is used, both an oxidation reaction and a hydrolysis reaction occur.

The chemical treatment can be carried out by storing the slurry in a known reaction tank and adding a treatment agent such as an oxidizing agent. As the reaction tank, a papermaking tower such as a bleaching tower can be used. The treatment (reaction) time of the chemical treatment step varies depending on the concentration and temperature of the slurry, the amount of the treatment agent added, and the like, and can be, for example, 0.5 hours or more and 12 hours or less.

The slurry that has undergone the chemical treatment is subjected to a neutralization treatment, a cleaning treatment, etc., if necessary, and is transferred using a pipe to be used in the next process. In the case of chemical treatment using an enzyme, the reaction can be terminated by raising the slurry temperature by injecting hot water (warm water) into the slurry and inactivating the enzyme.

It should be noted that it is preferable to use the sanitary pipe from the viewpoint of improving the possibility that the slurry remains on the wall surface of the pipe and the possibility that the pipe is easily clogged even in the transfer of the slurry in the chemical treatment step. In particular, in the chemical treatment step in which the oxidation treatment and the hydrolysis treatment are performed, if a gasket made of polytetrafluoroethylene having excellent alkali resistance, heat resistance and acid resistance is used as the gasket for the sanitary pipe, the durability of the gasket is durable. It is more preferable in that it can improve.

The crude defibration treatment step, which is one of the pretreatments, is a step of coarsely defibrating the pulp fibers in the slurry with a refiner. Pretreatment with a refiner that minimizes the gap and beats while applying a load effectively applies shearing force to the pulp fibers, causes fluffing of the pulp fibers, makes the pulp fibers flexible, and is preliminary. Debrisation occurs. The refiner is a device for beating pulp fibers, and a known device can be used. As the refiner, a conical type, a double disc refiner (DDR) and a single disc refiner (SDR) are preferable from the viewpoints that a shearing force can be efficiently applied to the pulp fibers and preliminary defibration can be promoted. .. It should be noted that the use of a refiner in the coarse defibration treatment step is also preferable from the viewpoint that separation and cleaning after the treatment become unnecessary.

The lower limit of the fine ratio of the pulp fibers charged into the tank through the pretreatment step is 60%, preferably 70%, and more preferably 75%. The upper limit of the fine ratio is 90%, preferably 85%. By setting this fine ratio to the above lower limit or more, the pulp fiber has undergone sufficient pretreatment (defibration), and further miniaturization can be efficiently performed in the miniaturization treatment by the high-pressure homogenizer. Further, by setting the fine ratio to the above lower limit or higher, it is possible to reduce the occurrence of clogging in the flow path of the pulp fiber when the pulp fiber is treated with a high-pressure homogenizer in the miniaturization treatment. On the other hand, by setting the fine ratio of the pulp fibers to the above upper limit or less, it is possible to suppress excessive pretreatment, particularly coarse defibration treatment step, and to save energy and improve efficiency in the entire manufacturing process. It is possible to increase the productivity of cellulose nanofibers. Here, the "fine ratio" refers to a mass-based ratio of pulp fibers having a fiber length of 0.2 mm or less and a fiber width of 75 μm or less. This fine ratio can be measured by a fiber analyzer "FS5" manufactured by Valmet. The fiber analyzer "FS5" can measure the length and width of the cellulose fibers with high accuracy by image analysis when the diluted cellulose fibers pass through the measurement cell inside the fiber analyzer.

After the pretreatment, a fine rate measuring step for measuring the fine rate of the pulp fiber may be provided.

This fine ratio can be adjusted by the amount of treatment in the pretreatment, particularly the coarse defibration treatment step. For example, increasing the processing time by the refiner, narrowing the interval (clearance) of the discs (plates) during processing by the refiner, disc blade width, groove width, blade height, blade crossing angle, disc The fine rate can be increased by combining the patterns of.

The average fiber length of the pulp fibers charged into the tank 10 through the pretreatment step is not particularly limited, but the lower limit is preferably 0.15 mm, more preferably 0.2 mm, and even more preferably 0.25 mm. On the other hand, as the upper limit, 0.5 mm is preferable, and 0.4 mm is more preferable. By subjecting pulp fibers having such a fiber length to a micronization treatment, energy saving and high efficiency of the entire manufacturing process can be achieved, and the productivity of cellulose nanofibers can be increased.

The produced slurry is charged into the tank 10 from the charging port 11 and stirred as needed. The temperature of the slurry transferred to the high pressure homogenizer 5 by the sanitary piping is controlled by a known method. The temperature of the slurry to be transferred is preferably, for example, 20 ° C. or higher and 70 ° C. or lower. By setting the temperature of the slurry in the above range, the fluidity of the slurry is improved, and the slurry can be transferred via the inflow / outflow pipe more efficiently.

First, the three-way valve 15, the two-way valve 25, and the two-way valve 30 are operated in the closing direction, and the valves connected to the pipes 23 and 12 of the three-way valve 18 are operated in the opening direction. Next, the high pressure pump 14 is operated to drain the slurry from the bottom of the tank 10. Then, the slurry is transferred to the high-pressure homogenizer 5 via the pipe 6, the pipe 7, the pipe 23, and the pipe 12.

<Step of miniaturization processing with a high-pressure homogenizer (T2)>
The T2 step is a step of refining the pulp fibers in the slurry transferred using the high-pressure homogenizer 5. As a method of performing the mechanical processing of the miniaturization step, the high pressure homogenizer 5 is used as described above.

<Step of transferring from the high-pressure homogenizer and charging into the second tank (T3)>
In the T3 step, the slurry that has been miniaturized by the high-pressure homogenizer 5 is transferred to the bottom of the tank 20 by a sanitary pipe and flows in from the bottom of the tank 20.

First, the three-way valve 18, the two-way valve 16 and the two-way valve 27 are operated in the closing direction, and the valves connected to the pipe 12 and the pipe 19 of the three-way valve 17 are operated in the opening direction. Then, the slurry that has been miniaturized by the high-pressure homogenizer 5 is introduced from the bottom of the tank 20 through the pipe 12, the pipe 19, the pipe 8 and the pipe 9 using the high-pressure pump 14.

<Step of transferring from the second tank to the high-pressure homogenizer by sanitary piping (T4)>
In the T4 step, the slurry flowing into the tank 20 flows out from the bottom of the tank 20 and is transferred to the high-pressure homogenizer 5 by a sanitary pipe.

First, the three-way valve 17, the two-way valve 16 and the two-way valve 27 are operated in the closing direction, and the valves connected to the pipe 24 and the pipe 12 of the three-way valve 18 are operated in the opening direction. Next, the high pressure pump 14 is operated to drain the slurry from the bottom of the tank 20. Then, the slurry is transferred to the high-pressure homogenizer 5 via the pipe 9, the pipe 8, the pipe 24, and the pipe 12.

<Step of refining again with a high-pressure homogenizer (T5)>
In the T5 step, the pulp fibers in the transferred slurry are re-miniaturized by the high-pressure homogenizer 5.

In the present embodiment, after the T5 step, the three-way valve 18 and the two-way valve 25 are operated in the closed direction, the valves connected to the pipe 12 and the pipe 22 of the three-way valve 17 are operated in the open direction, and the three-way valve is operated. The valve connected to the pipe 22 and the pipe 7 of the pipe 15 is operated in the opening direction. Then, the slurry that has been miniaturized by the high-pressure homogenizer 5 is introduced from the bottom of the tank 10 through the pipe 12, the pipe 22, the pipe 7, and the pipe 6 using the high-pressure pump 14, and then the T1 step is performed again. The T5 step may be repeated. In this way, cellulose nanofibers are produced by circulating a slurry in one high-pressure homogenizer and two tanks using a sanitary pipe and efficiently performing a plurality of miniaturization treatments.

The cellulose nanofibers obtained by the miniaturization treatment are sufficiently finely divided and have one peak in the pseudo particle size distribution curve measured by the laser diffraction method in the water-dispersed state. The peak particle size (mode) in the pseudo particle size distribution curve is preferably 5 μm or more and 25 μm or less. When the obtained cellulose nanofibers have such a particle size distribution, they can exhibit sufficiently finely divided and good performance. The "pseudo particle size distribution curve" means a curve showing a volume-based particle size distribution measured using a particle size distribution measuring device (for example, a laser diffraction / scattering type particle size distribution measuring device manufactured by Seishin Enterprise Co., Ltd.).

The cellulose nanofibers thus obtained are filter media, filter aids, base materials for ion exchangers, fillers for chromatographic analysis equipment, fillers for blending resins and rubbers, cosmetic blenders, and viscosity preservatives. It can be widely used as a toughener for food raw material dough, a water retention agent, a food stabilizer, a low-calorie additive, an emulsion stabilization aid, and the like.

[Other Embodiments]
It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is not limited to the configuration of the above-described embodiment, but is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. To.

According to the cellulose nanofiber manufacturing apparatus and the cellulose nanofiber manufacturing method of the present invention, it is possible to efficiently manufacture cellulose nanofibers by suppressing the occurrence of clogging and contamination of pipes.

1 Cellulose nanofiber manufacturing equipment 4, 39 Stirrer 5 High-pressure homogenizer 6, 9 Piping 7, 8, 12, 19, 22, 23, 24, 31, 32, 33, 34, 35, 36 Piping 10, 20 Tank 11, 21 Input port 13 Pump 14 High pressure pump 15, 17, 18 Three-way valve 16, 25, 27, 30 Two-way valve 40 Ferrule type joint 41, 42 Ferrule 43 Ferrule gasket 44, 45 Clamp 51 Upstream side flow path 52 Downstream side flow path 60 Threaded Fittings 61 Threaded Sleeves 62 Threaded Liners 63, 64 Hex Nuts 65 L-shaped Gaskets S1, S2, S3 Slurry X Confluence

Claims (4)

A device for producing cellulose nanofibers that refines pulp fibers in a slurry.
A high-pressure homogenizer that refines the pulp fibers in the slurry,
A tank for storing the slurry that has been miniaturized with pulp fibers using the high-pressure homogenizer, and
Equipped with the high-pressure homogenizer and piping connected to the tank,
A device for manufacturing cellulose nanofibers, which is a sanitary pipe in which the pipe is connected via a joint fitted with a gasket. The apparatus for producing cellulose nanofibers according to claim 1, wherein the gasket is made of a fluororesin. The apparatus for producing cellulose nanofibers according to claim 1 or 2, wherein the pulp fibers in the slurry having a solid content concentration of 0.1% by mass or more and 8.0% by mass or less are micronized. A process of refining pulp fibers in a slurry using a high-pressure homogenizer, and
The slurry is provided with a step of transferring the slurry obtained by refining the pulp fiber by a sanitary pipe.
A method for producing cellulose nanofibers, wherein the slurry solid content concentration is 0.1% by mass or more and 8.0% by mass or less.

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