KR20200012103A - An apparatus and method for mass producting nanocellulose fiber - Google Patents

Abstract

The present invention relates to nanocellulose fiber manufacturing apparatus and method, capable of mass-producing nanocellulose fibers by continuously pulverizing and homogenizing cellulose fibers in raw materials.

Description

An apparatus and method for mass production of nanocellulose fibers

The present invention relates to a nanocellulose fiber manufacturing apparatus and a nanocellulose fiber manufacturing method for mass production of nanocellulose fibers.

Cellulose (cellulose) is the most important natural polymer material, its own properties are very useful material. Among them, nanocellulose is expected to open up new sustainable functions. Nanocellulose, which is nanoscale in diameter and length, has increased interactions with water, organic and polymeric materials, nanoparticles, living cells, etc., due to their increased surface area.

Particularly, since nanocellulose fibers are strongly crystallized by hydrogen bonds, they have five times the strength of ferrous metals and the coefficient of linear thermal expansion of less than 1/10 of glass fibers, and account for more than 50% of plant resources such as wood. It's a sustainable resource. However, until now, the industrial use is hardly achieved due to its manufacturing price and difficulty of handling, and researches are actively conducted in various countries around the world to improve this.

Such nanocellulose fibers are generally produced by mechanical treatment. However, wood or non-wood biomass, which is the raw material of nanocellulose fibers, has a variety of pretreatments for efficiently crushing these structures because, besides cellulose, materials such as hemicellulose and lignin combine to form rigid structures. Methods have been proposed.

The most used equipment for producing nanocellulose fibers is a grinder. The grinder is spaced apart by two ceramic grinding discs at appropriate intervals, and the disk below rotates at a high speed while the disk is fixed. Thus, the cellulose fibers fed into the disc are compressed laterally in the disc by centrifugal force. At this time, both sides of the disk has a rapidly rotating grinding stone (grinding stone) to act on the shear force and friction force on the cellulose fiber, and as a result nano-structure. However, this method has a disadvantage in that mass production is difficult because it must be produced in batch.

On the other hand, the most commercialized mechanical treatment is a high-pressure homogenizer. It mixes cellulose fibers with distilled water to make a suspension and then homogenizes them under high pressure. The high pressure causes the fibers to pass through a thin slit quickly, subjecting to large shear and impact forces, and separating them into nanofibers. This high pressure homogenizer has the advantage of making a large amount of nanofibers, but has a disadvantage in that it takes a lot of time and energy to make a nanostructure fiber of a dense microstructure.

For reference, previous research has shown that in order to commercialize nanocellulose fibers, the energy required for mechanical treatment should be less than 1,000 kWh per ton of biomass. However, high-pressure homogenizers consume 30,000 to 70,000 kWh / ton of energy, which is several tens of times this value, so research is needed to reduce energy costs.

That is, it is possible to mass-produce nanocellulose fibers, and it is necessary to develop a technology capable of minimizing energy consumption when manufacturing the nanocellulose fibers.

Republic of Korea Patent Publication No. 10-2016-0000826

The present invention is to solve the above problems, to provide a nanocellulose fiber manufacturing apparatus and nanocellulose fiber manufacturing method capable of mass production of nanocellulose fibers.

The invention in one embodiment,

A pulverizing unit for pulverizing the raw material including cellulose fibers and grinding the average diameter of the cellulose fibers to 60 to 120 nm;

Homogenizing part for homogenizing so that the average diameter of the cellulose fiber passing through the grinding part is 5 to 60 nm; And

Filter unit for filtering the homogenized cellulose fiber to remove the solvent; It provides a nano-cellulose fiber manufacturing apparatus comprising a.

Further, in another embodiment of the present invention,

Preparing a raw material including cellulose fibers into a suspension, and introducing the suspension into a pulverizing unit to pulverize cellulose fibers in the suspension to an average length of 60 to 120 nm in the pulverizing unit;

Fluidly moving the suspension from the mill to the homogenizer and homogenizing the cellulose fibers in the suspension to an average diameter of 5 to 60 nm; And

Filtering the suspension in a filter portion to remove the solvent from the suspension to increase the concentration of the suspension; It provides a method for producing nanocellulose fibers.

The apparatus and method for manufacturing a nanocellulose fiber according to the present invention can easily prepare nanocellulose fibers by pre-treating the raw materials and then continuously grinding and homogenizing them.

In addition, it is possible to mass-produce nanocellulose fibers and reduce energy consumption.

1 is a block diagram showing the configuration of a nanocellulose fiber manufacturing apparatus according to the present invention.
Figure 2 is an overall conceptual view showing the configuration of a nanocellulose fiber manufacturing apparatus according to the present invention.
Figure 3 is a flow chart showing a method for producing nanocellulose fibers according to the present invention.
Figure 4 is a morphological picture of the cellulose fibers prepared through the mill in the example ((a) once, (b) three times, (c) five times, (d) seven times, (e) nine times, ( f) 10 passes)
Figure 5 is a morphological picture of the cellulose fibers produced through the homogenization in the embodiment ((a) once, (b) twice, (c) three times, (d) four times, (e) five passes)
Figure 6 is a graph showing the diameter and the standard deviation of the cellulose fiber according to the number of times of grinding and homogenization in the embodiment ((a) the average diameter of the cellulose fiber, (b) the standard deviation of the cellulose fiber length).
7 is a graph showing the viscosity of cellulose fibers produced according to the number of treatments of grinding and homogenization.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In the present invention, the terms “comprises” or “having” are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present disclosure does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

The present invention relates to a nanocellulose fiber manufacturing apparatus and a nanocellulose fiber manufacturing method for mass production of nanocellulose fibers.

In one embodiment, the nanocellulose fiber manufacturing apparatus according to the present invention,

A pulverizing unit for pulverizing the raw material including cellulose fibers and grinding the average diameter of the cellulose fibers to 60 to 120 nm;

Homogenizing part for homogenizing so that the average diameter of the cellulose fiber passing through the grinding part is 5 to 60 nm; And

Filter unit for filtering the homogenized cellulose fiber to remove the solvent; It includes a nano cellulose fiber manufacturing apparatus comprising a.

Prior to the description, the term "nanocellulose fiber" in the terms used in the present invention means a rod-shaped fiber of nano *? * Micrometer size in which cellulose chains are bundled and tightly bonded. In one example, the present invention relates to an apparatus and a method for producing nano *? * Micrometer-sized fibers by preparing raw materials comprising cellulose fibers in suspension, pretreating them, and then grinding and homogenizing them.

On the other hand, the "raw material containing cellulose fibers" is a coniferous pulp, such as bamboo pulp, hemp pulp, flax pulp, bagas pulp straw pulp, pine pulp, spruce pulp, conifer pulp, eucalyptus pulp, oak pulp, etc. It may include one or more selected from the group consisting of hardwood pulp, unbleached pulp, bleached pulp and deinked pulp.

In the present invention, "suspension" means that the solid fine particles are dispersed and floating in the liquid, the present invention means that the cellulose fibers are dispersed and floating in the liquid. At this time, the concentration of the cellulose fibers contained in the suspension may be 0.1 to 2% by weight.

In the present invention, both "pulverization" and "homogenization" are performed to reduce the size of cellulose fibers, but in one example, "pulverization" is performed so that the average diameter of cellulose fibers is 60 to 120 nm by a colloid mill. By crushing, “homogenization” may mean grinding the cellulose fibers evenly with an average diameter of 5 to 60 nm by means of a high pressure homogenizer.

The present invention also provides a method for producing nanocellulose fibers.

In one example, the method for producing nanocellulose fibers according to the present invention,

Preparing a raw material including cellulose fibers into a suspension, and introducing the suspension into a grinding unit, thereby grinding the cellulose fibers in the suspension to an average length of 60 to 120 nm in the grinding unit;

Fluidly moving the suspension from the mill to the homogenizer and homogenizing the cellulose fibers in the suspension to an average diameter of 5 to 60 nm; And

Filtering the suspension in a filter portion to remove the solvent from the suspension to increase the concentration of the suspension; It includes.

In the above production method, the fluid movement of the suspension from the milling unit to the homogenizing unit, the suspension can be moved to the homogenizing unit sequentially or continuously along the fluid flow direction.

In one example, nanocellulose fibers can be easily prepared by continuously grinding and homogenizing cellulose fibers in the raw material, wherein the capacity of the nanocellulose fibers produced is 0.9 to 10 ton / day, 1 to 8 ton / day, 1.5 to 6 ton / day, 2 to 4 ton / day, or 2 ton / day.

Hereinafter, with reference to the accompanying drawings will be described in detail the nanocellulose fiber manufacturing apparatus and nanocellulose fiber manufacturing method of the present invention.

1 is a block diagram showing the configuration of a nano cellulose fiber manufacturing apparatus according to an embodiment of the present invention.

First, referring to Figure 1, the nanocellulose fiber manufacturing apparatus 100 of the present invention is a raw material containing cellulose fiber (cellulose fiber) is injected, the grinding unit for grinding the average diameter of the cellulose fiber 60 to 120 nm 120; Homogenizer 130 for homogenizing the average diameter of the cellulose fibers passed through the grinding unit 120 to 5 to 60 nm; And a filter unit 140 for filtering the homogenized cellulose fiber to remove the solvent. Meanwhile, the cellulose fiber supplied to the grinding unit 120 may be in a suspension state.

In addition, the nanocellulose fiber manufacturing apparatus 100 may further include a pretreatment unit 110 for pretreating the raw material with an alkaline solution. The pretreatment unit 110 is a structure having a stirring means therein, and may be a kind of storage tank for accommodating and pretreating raw materials. In the pretreatment unit 110, a raw material containing cellulose fibers may be prepared as a suspension, and may be provided as a space for pretreatment.

The present invention is to produce a large amount of nanocellulose fibers, it is possible to manufacture a nanocellulose fiber of 0.9 to 10 ton / day, the pre-edge portion 110 also 200 to be able to produce a large amount of nanocellulose fibers It is desirable to have a capacity that can handle the 1000 kg / h range. The pretreatment unit 110 may be a raw material containing cellulose fibers through the raw material input flow path to prepare the raw material as a suspension, and may perform alkali pretreatment, and the cellulose fiber after the pretreatment is discharged through the fluid line and ground Supplied to the unit 120.

The grinding unit 120 serves to grind the cellulose fibers passed through the pretreatment unit 110, and in one example, a grinder such as a disk type colloid mill including an upper disk and a lower disk. Can be. In addition, the pulverization unit 120 is for pulverizing a large capacity of cellulose fibers, may have a capacity of 200 to 1000 kg / h, the average diameter of the cellulose fibers passed through the pretreatment unit 110 to 60 to 120 nm Can be crushed finely. The suspension is pulverized is discharged to the fluid line, it is moved to the homogenizer 130.

The homogenization unit 130 serves to crush the pulverized cellulose fiber evenly so that the average diameter is 5 to 60 nm. In one example, the homogenizer 130 may be a high pressure homogenizer, and when the pressure inside the homogenizer is 30,000 psi, it may process 4.0 to 4.7 L / min of raw material. The homogenized cellulose fiber is supplied to the filter portion 140 via a fluid line to remove the solvent in the suspension.

Specifically, the suspension passed through the crushing unit 120 and the homogenizing unit 130 in the filter unit 140 is separated into a solvent and cellulose fibers. That is, the suspension having passed through the homogenization unit 130 may be filtered by the filter unit 140 to increase the concentration of the suspension by removing the solvent in the suspension. On the other hand, the filter unit 140 can be used for both filter press, belt press and centrifugal filtration in order to separate and recover the cellulose fibers from the suspension. Do. In one example, the filter press may be equipped with a filter made of a polymer filter cloth, such as polypropylene, the filter may have an air permeability of 0.1 to 10 cm ³ / cm ² / s, more specifically 0.1 To 8 cm ³ / cm ² / s, 0.1 to 6 cm ³ / cm ² / s, 0.1 to 4 cm ³ / cm ² / s, 0.1 to 2 cm ³ / cm ² / s, 0.1 to 1 cm ³ / cm Air permeability of ² / s, 0.2 to 0.8 cm ³ / cm ² / s, 0.3 to 0.7 cm ³ / cm ² / s, 0.4 to 0.6 cm ³ / cm ² / s, or 0.5 cm ³ / cm ² / s Can have.

Figure 2 is an overall conceptual view showing the configuration of a nanocellulose fiber manufacturing apparatus according to the present invention. With reference to Figure 2, it will be described a specific configuration of the nanocellulose fiber manufacturing apparatus according to the present invention.

Nanocellulosic fiber manufacturing apparatus 100 of the present invention in more detail, the first storage tank 110 is formed, the raw material input flow path is formed, the mixture of the input raw material and water to produce a suspension; A grinding unit 120 for grinding the suspension introduced from the first storage tank 110; A first fluid line 121 through which the suspension passed through the grinding unit 120 is fluidly moved to the first storage tank 110; A second storage tank 131 supplied with a suspension from the first storage tank 110 via the crushing unit 120; A second fluid line 122 fluidly connecting the first fluid line 121 and the second storage tank 131 to which the suspension passed through the crusher 120 is fluidly moved to the second storage tank 131; Homogenizer 130 for homogenizing the suspension introduced from the second storage tank 131; A third fluid line 133 through which the suspension passed through the homogenizer 130 is fluidly moved to the second storage tank 131; A filter unit 140 for removing the solvent by filtering the suspension passed through the homogenizing unit 130 from the second storage tank 131; And a fourth fluid line 134 fluidly connecting the third fluid line 133 and the filter unit 140 and the suspension passed through the homogenizer 130 to the filter unit 140.

First, the first storage tank 110 means the pretreatment unit 110, and has a structure provided with a stirring means therein. The first storage tank 110 is a space in which the mixing and pretreatment of the raw materials is made, and the raw material is prepared as a suspension and provided as a space for pretreating the suspension. In addition, the first storage tank 110 has a raw material input flow path is formed on one side, each line is formed so that the suspension can flow into and out of the crushing unit 120. At this time, the fluid line connecting the first storage tank 110 and the grinding unit 120, that is, the fluid line through which the suspension passed through the grinding unit 120 flows into the first storage tank 110 is a first fluid line. It may be referred to as (121).

The suspension prepared in the first storage tank 110 is fluidized to the pulverization unit 120 to perform a pulverization process, and the pulverized suspension is fluid to the first storage tank 110 via the first fluid line 121. Is moved. In addition, the suspension of the first storage tank 110 is stirred, and the suspension is supplied to the grinding unit 120 again to perform the grinding process. That is, the process of pulverizing cellulose fibers by injecting the suspension into the crushing unit 120 may be repeatedly performed, specifically, 8 to 15 times. Meanwhile, a first-a storage tank 111 for receiving a suspension flowing out of the crushing unit 120 on the first fluid line 121 between the first storage tank 110 and the crushing unit 120 is included. . For example, the first-a storage tank 111 serves to supply the first storage tank 110 after the first suspension of the contained suspension.

In one example, the suspension is repeatedly performed 8 to 15 times the process of the first storage tank 110 → crushing unit 120 → first-a storage tank → first storage tank 110. The process may be repeatedly performed 8 to 15 times, 9 to 13 times or 10 times.

The grinding unit 110 of the present invention may be a colloid mill including an upper disk (not shown) and a lower disk (not shown). In addition, the lower disk of the crushing unit 120 is fixed, the upper disk may be configured to rotate. Specifically, when the suspension is supplied to the crushing unit 110, the suspension is supplied to the center of the lower disk by gravity, the upper disk is rotated, the suspension is a narrow gap between the lower disk and the upper disk Through the circumferential surface. At this time, the suspension may be subjected to shear, centrifugal, and frictional forces to produce fine particles of the dispersed phase.

The upper disk of the grinding unit 110 may be configured to rotate for 60 to 100 minutes at 1,750 rpm to 3,500 rpm.

An interval between the upper disk and the lower disk of the crushing unit 110 may range from 20 to 40 μm. Specifically, the interval between the upper disk and the lower disk may be in the range of 20 to 40 μm, 21 to 35 μm, 22 to 30 μm, 23 to 25 μm, or 24 μm. Here, when the gap between the upper disk and the lower disk is less than 20 ㎛, the gap between the disk is too narrow, it is difficult to crush a large amount of cellulose fibers, when exceeding 40 ㎛, the gap between the disk is too wide, grinding The cellulosic fibers cannot be easily pulverized in the part, and the cellulose fiber in the range of 60 to 120 nm cannot be provided in the pulverization part.

Meanwhile, the gap between the upper disk and the lower disk is adjustable and can be changed during the grinding process. The process of pulverizing cellulose fibers by injecting the suspension into the crushing unit 110 is repeatedly performed. In particular, as the number of repetitions increases, the interval between the upper and lower disks may be reduced. In one example, the interval between the upper and lower discs may be set to 32 μm until the second iteration process, and the interval between the upper and lower discs may be set to 30 μm in the third and fourth cycles, and the fifth and sixth cycles may be set. In the 7th and 8th rounds, the gap between the upper and lower disks can be set to 26 µm. In the 7th and 8th rounds, the gap between the upper and lower disks can be set to 26µm. Can be set to This is to more efficiently pulverize the cellulose fibers that become finer as the number of repeated processes increases.

On the other hand, the average diameter of the upper and lower disks may range from 200 to 450 mm, 220 to 440 mm range, 240 to 430 mm range, 260 to 420 mm range, 280 to 410 mm range, 300 to 410 mm range, It may range from 320 to 400 mm, range from 340 to 390 mm, range from 350 to 380 mm, range from 360 to 370 mm or 360 mm.

In addition, the crushing unit 110 of the present invention can easily manufacture a large-capacity nanocellulose fiber, the capacity can be pulverized the cellulose fiber at a speed in the range of 200 to 1000 kg / h. Specifically, the cellulose fibers may be ground at a speed in the range of 300 to 900 kg / h, 400 to 800 kg / h, 500 to 700 kg / h or 600 kg / h.

And, when the average diameter of the cellulose fiber is 60 to 120 nm, it can be supplied to the homogenizer 130 to be described later. At this time, the pulverized suspension may be fluidly moved to the second storage tank 131 through the second fluid line 122.

When the suspension passed through the crusher 120 is supplied to the homogenizer 130, the suspension is stored in the first fluid line 121, the crusher 120, the first storage tank 110, or the first-a storage. The tank 111 may be supplied to the homogenizer 130. However, since the suspension passed through the crushing unit 120 is preferably moved to the homogenizing unit 130 after the first stirring, the suspension passing through the first-a storage tank 111 may be supplied to the homogenizing unit 130. Can be. In this case, the suspension in the first-a storage tank 111 does not move to the first storage tank 110, but the suspension contained in the first-a storage tank 111 via the grinding unit 120 is removed. The two fluid lines 122 may be supplied to the homogenizer 130.

In one example, the second fluid line 122 connects the first fluid line 121 and the second storage tank 131, and the second fluid line 122 and the first fluid line 121 are connected to each other. The ground portion may include a valve. In addition, the fluid movement direction of the suspension in the first fluid line 121 may be controlled by the valve. Specifically, by the driving of the valve, the suspension in the first fluid line 121 may be moved to the first storage tank 110, or may be moved to the second storage tank 131. The valve may be any valve as long as it is a valve for controlling the direction of movement of the fluid.

The diameter of the cellulose fibers pulverized through the above-described crushing unit 110 may be 60 to 120 nm, in which case, the viscosity of the suspension flowing into the second fluid line 121 and moved to the second storage tank 131. May range from 10 to 20 Pa.s at a shear rate of 0.1 / s.

The suspension passed through the crushing unit 110 is supplied to the second storage tank 131, and the suspension introduced into the second storage tank 131 fluidly moves to the homogenization unit 130 to perform a homogenization process. . In addition, the suspension having passed through the homogenization unit 130 is fluidly moved to the second storage tank 131 via the third fluid line 133. The suspension in the second storage tank 131 is agitated, and the stirred suspension is supplied to the homogenizer 130 again to perform the homogenization process again. That is, the process of homogenizing the cellulose by supplying the suspension to the homogenizing unit 130 is performed repeatedly, specifically, it may be performed repeatedly 2 to 10 times.

Meanwhile, the second storage tank 132 may include a second storage tank 132 that receives a suspension flowing from the homogenization unit 130 on the third fluid line 133 between the second storage tank 131 and the homogenization unit 10. Can be. For example, the second 2-a storage tank 132 accommodates and stirs the suspension passed through the homogenizer 130 and provides a space for supplying the stirred suspension to the second storage tank 131.

In one example, the suspension may be repeatedly performed 2 to 10 times the process of the second storage tank 131 → homogenizer 130 → the second 2-a storage tank 132 → the second storage tank 131. Can be. Specifically, the process may be performed repeatedly 2 to 10 times, 2 to 9 times, 3 to 8 times, 3 to 7 times, 4 to 6 times or 5 times. This process can be performed for 30 minutes to 60 minutes per one process, assuming that the capacity of the homogenizing unit is 100L can be produced nanocellulose fibers of excellent physical properties. In the conventional general homogenization process, since it has to be performed about 10 times to obtain a cellulose fiber of the desired diameter, it has to consume a very long time and a lot of energy. On the other hand, in the case of the present invention, since the crushing unit 120 and the homogenizing unit 130 through the complex, it is possible to reduce the number of repeated processes of the homogenizing unit 130 compared to the conventional, the overall process time and energy when manufacturing nanocellulose fibers Reduce consumption

The homogenizer 130 of the present invention may be a high pressure homogenizer including a nozzle having an average diameter of 50 to 200 μm. Specifically, the diameter of the nozzle may be 50 to 200 μm, 70 to 180 μm, 80 to 160 μm, 80 to 140 μm. In one example, the diameter of the nozzle can be 87 μm or 120 μm.

On the other hand, the high pressure homogenizer is composed of a homogenizer valve and a high pressure pump. When the suspension is fed to the valve with a high pressure pump, the suspension passes a narrow gap between the valve and the valve seat at a high speed of 250 m / s. At this time, the cellulose fibers are crushed by shearing and colliding at a right angle to the break ring at the exit of the dispersed phase, and the cellulose fibers are further crushed by impact, and the pressure is suddenly lowered from high pressure to low pressure, thereby expanding and producing finer particles. do. The spacing between the valve and the valve seat can be adjusted to a size of 15 to 30 μm with a strong spring. This means to control the homogeneous pressure. As a high pressure pump, a multi-cylinder flanger pump may be used.

The internal pressure of the homogenizer 130 may be in the range of 15,000 to 35,000 psi, 18,000 to 34,000 psi range, 21,000 to 33,000 psi range, 24,000 to 32,000 psi range, 27,000 to 31,000 psi range, or 30,000 psi, In one example, when the internal pressure of the homogenizer 130 is 30,000 psi, it is possible to homogenize the cellulose fiber at a speed in the range of 4 to 4.7L / min.

Meanwhile, a heat exchanger 135 may be included on the third fluid line 121 between the homogenizer 130 and the second-a storage tank 132 to cool the suspension flowing out of the homogenizer 130. have. In detail, the suspension flowing out of the homogenizer 130 is introduced into the second-a storage tank 132 via the heat exchanger 135. The heat exchanger 135 may heat the heat generated when the cellulose fiber is homogenized in the homogenizer 140, thereby cooling. The heat exchanger 135 is a structure in which a separate cooler 136 is formed at one side. The heat exchanger 135 may have a cooling medium inlet / outlet line at one side thereof. Cooling is maintained such that the temperature of the suspension flowing into the second-a storage tank 132 through the heat exchanger 135 is maintained at 10 to 25 ° C.

The suspension passed through the homogenizer 130 is supplied to the filter unit 140 through the fourth fluid line 134. Specifically, when the average diameter of the cellulose fiber is 5 to 60 nm, it can be supplied to the filter unit 140 to be described later. When the suspension passed through the homogenizer 130 is supplied to the filter unit 140, the suspension is stored in the third fluid line 133, the homogenizer 130, the second storage tank 131, or the second storage-a. It may be supplied to the filter unit 140 from the tank 132. However, since the suspension passed through the homogenization unit 130 is preferably moved to the filter unit 140 after being stirred, the suspension passed through the second-a storage tank 132 may be supplied to the filter unit 140. . In this case, the suspension contained in the second-a storage tank 132 via the homogenization unit 130 does not move to the second storage tank 131, but the filter portion (2) in the second-a storage tank 132. 140). In one example, the fourth fluid line 134 may fluidly connect the third fluid line 133 and the filter unit 140, or may fluidize the 2-a storage tank 132 and the filter unit 140. Can connect On the other hand, the ground portion that is connected to the fourth fluid line 133 and the fourth fluid line 134 may include a valve, by the valve to control the fluid movement direction of the suspension in the third fluid line 133 can do. Specifically, by the driving of the valve, the suspension in the third fluid line 133 may be moved to the second storage tank 131, or may be moved to the filter unit 140. The valve may be any valve as long as it is a valve for controlling the direction of movement of the fluid.

At this time, the cellulose fiber diameter that is moved to the filter unit 140 through the homogenizing unit 130 described above may be 5 to 60 nm, flows out to the fourth fluid line 134, is moved to the filter unit 140 The viscosity of the suspension may range from 25 to 80 Pa · s at a shear rate of 0.1 / s.

Next, the suspension passed through the homogenizer 130 is introduced into the filter unit 140 for filtering the cellulose fibers homogenized in the suspension to remove the solvent. The filter unit 140 may be a filter press equipped with a filter having a fine hole. The filter press can be freely selected in consideration of the turbidity of the suspension to be obtained since the size of the particles to be passed varies depending on the pore size of the filter cloth. Specifically, the filter unit 140 may be used for both filter press, belt press and centrifugal filtration to separate and recover the cellulose fibers from the suspension. have. In one example, the filter press may be equipped with a filter made of a polymer filter cloth such as polypropylene, the filter may have an air permeability of 0.1 to 10 cm ³ / cm ² / s, more specifically 0.1 to 8 cm ³ / cm ² / s, 0.1 to 6 cm ³ / cm ² / s, 0.1 to 4 cm ³ / cm ² / s, 0.1 to 2 cm ³ / cm ² / s, 0.1 to 1 cm ³ / cm ² air permeability of / s, 0.2 to 0.8 cm ³ / cm ² / s, 0.3 to 0.7 cm ³ / cm ² / s, 0.4 to 0.6 cm ³ / cm ² / s, or 0.5 cm ³ / cm ² / s Can be. In another example, 20 to 24 filter cloths may be stacked and used. Accordingly, finer nanocellulose fibers can be filtered.

On the other hand, in another example, it may include a first filter and a second filter. The first filter and the second filter have different pores, and the suspension passing through the first filter sequentially recovers the nanocellulose fibers by passing through the second filter.

Figure 3 is a flow chart showing a method for producing nanocellulose fibers according to the present invention. With reference to Figure 3, it will be described in detail a nanocellulose fiber manufacturing method according to the present invention.

The method for producing nanocellulose fibers of the present invention includes preparing a raw material containing cellulose fibers as a suspension and mixing an alkaline solution of pH 9 to pH 13 to pretreat the raw material (S100); Injecting the suspension into the grinding unit, the step of grinding the cellulose fibers in the suspension in the grinding unit to an average diameter of 60 to 120 nm (S200); Fluidly moving the suspension from the milling unit to the homogenizing unit and homogenizing the cellulose fibers in the suspension to an average diameter of 5 to 60 nm (S300); And filtering the suspension in a filter part to remove the solvent from the suspension to increase the concentration of the suspension (S400). It includes.

The raw material containing the cellulose fiber is a hardwood pulp, such as coniferous pulp, such as bamboo pulp, hemp pulp, flax pulp, non-wood pulp such as bagasse pulp, pine pulp, spruce pulp, eucalyptus pulp, oak pulp, It may comprise one or more selected from the group consisting of unbleached pulp, bleached pulp and deinked pulp.

In one example, the raw material comprising cellulose fibers may comprise micro sized cellulose fiber powder.

First, a raw material containing cellulose fibers is prepared in a suspension of 0.1 to 2% by weight, pretreated with an alkaline solution, and fed into a pulverizing unit to pulverize the cellulose fibers in the suspension to an average diameter of 60 to 120 nm in the pulverizing unit. . At this time, the suspension is preferably 0.1 to 2% by weight. In particular, when the concentration of the suspension exceeds 2% by weight, it causes the blockage of the valve of the homogenizer due to the viscosity rise of the suspension and due to the pressure rise, the process can be stopped. In addition, when the suspension is less than 0.1% by weight, too little cellulose fiber relative to the solvent, it is not easy to crush and homogenize the cellulose fiber.

In the step of pretreatment of the raw material (S100), the suspension may be treated with an alkali of sodium hydroxide (NaOH) at a concentration of 1 to 10% or potassium hydroxide (KOH) at a concentration of 1 to 10% for 1 to 2 hours. In addition, the suspension that has been pretreated may include a process of washing by distilling with distilled water at least 10 times using a depressurized filtration device in which a Buchner funnel is installed. Specifically, washing may be performed until finally distilled water to be filtered pH 5-7.

On the other hand, natural cellulose fibers are a plurality of cellulose chains (α-1, 4 glucan) to form a micelle, and also a plurality of micelles to form microfibrils (microfibers), in the present invention, the cellulose fibers in an alkaline solution Immersion can swell the amorphous region between the micelles and micelles in the fiber. Specifically, the alkaline solution pretreatment is followed by the removal of some of the components from the fiber bundle that swell the raw fibers and firmly fix microfibrils (fine fibers) such as hemicellulose, lignin, etc. in the cellulose fibers. When crushing and homogenizing the raw materials, the number of treatments (the number of repetitions) can be reduced in comparison with the raw material which has not been pretreated, thereby reducing energy consumption and the like. In addition, enzymatic hydrolysis, which is an environmentally friendly process that does not require a large amount of chemicals, can be applied to the nanocellulose manufacturing method of the present invention. There are various cellulose degrading enzymes, but among them, three species such as endoglucanase, cellobiohydrolase, and β-glucosidase can be mainly applied, and they can hydrolyze micro-sized cellulose fibers by reacting with amorphous regions and terminal chemical groups in the cellulose chain polymer. Can be. This means that when the pulverization and homogenization process, which is a post-treatment process, is introduced, nanocellulose made from pulp or fiber treated with enzymatic hydrolysis may produce smaller and more uniform cellulose fibers than the same number of treatments, or The production of nanocellulose fibers of a certain size has the advantage of dramatically reducing the energy consumption of mechanical treatment.

Next, the step of pulverizing cellulose fibers by adding the suspension to the pulverization unit may be repeatedly performed 8 to 15 times. Specifically, the grinding process is repeatedly performed 8 to 15 times, 9 to 13 times or 10 times. And, when the average diameter of the cellulose fiber is 60 to 120 nm, it can be supplied to the homogenizer 130 to be described later. On the other hand, when the grinding step is less than eight times, the energy consumption is large because the homogenization step described later in order to produce a cellulose fiber of the desired diameter is more large, and even if more than 15 times, grinding the cellulose in the grinding unit Because of the limitations, it is unnecessary because the average diameter of the cellulose fibers in the milled portion does not become finer than 60 to 120 nm.

As described above, the grinding unit 110 may be a colloid mill including an upper disk and a lower disk, and the upper disk of the grinding unit 110 may be configured to rotate at 1,750 to 3,500 rpm.

In addition, the interval between the upper disk and the lower disk is characterized in that it is set to the 20 to 40 ㎛ range. Specifically, the interval between the upper disk and the lower disk can be set to 20 to 40 ㎛ range, 21 to 35 ㎛ range, 22 to 30 ㎛ range, 23 to 25 ㎛ range, or 24 ㎛.

In addition, the crushing unit 110 of the present invention can easily manufacture a large-capacity nanocellulose fiber, the capacity can be pulverized the cellulose fiber at a speed in the range of 200 to 1000 kg / h. Specifically, the cellulose fibers may be ground at a speed in the range of 300 to 900 kg / h, 400 to 800 kg / h, 500 to 700 kg / h or 600 kg / h.

Cellulose fibers pulverized through the above-described crushing unit 110 is discharged to the first fluid line, and moved to the homogenizing unit 130, the viscosity of the moved suspension is 10 to 20 Pa.s at a shear rate of 0.1 / s It can be a range.

Then, the suspension is fluidized from the pulverization unit 120 to the homogenization unit 130, and the cellulose fibers in the suspension are homogenized to an average diameter of 5 to 60 nm. At this time, the step of homogenizing the suspension into the homogenization unit 130 is performed repeatedly 2 to 10 times, the internal pressure of the homogenization unit 130 may be in the range of 15,000 to 35,000 psi. Specifically, the step of homogenizing the suspension into the homogenizer may be repeated 2 to 10 times, 2 to 9 times, 2 to 8 times, 3 to 7 times, 3 to 6 times, 4 to 6 times, or 5 times. Can be done. If the step of homogenization is less than two, the cellulose fibers may not be homogenized to the desired diameter, and if exceeded ten times, a problem may occur in which too much energy power is consumed.

In addition, the internal pressure of the homogenizer may range from 15,000 to 35,000 psi, and may be 18,000 to 34,000 psi, 21,000 to 33,000 psi, 24,000 to 32,000 psi, 27,000 to 31,000 psi, or 30,000 psi.

If, in the homogenization step, the internal pressure of the homogenizer is less than 15,000 psi, the pressure applied to the suspension may be too low to cause a lot of homogenization time, and if it exceeds 35,000 psi, excessive energy consumption occurs and the nozzle An excessive load may occur, and the pressure in the above range is preferable.

In one example, the method for producing nanocellulose fibers according to the present invention may satisfy the following equation:

[Equation 1]

V ₁ / V ₂ ≥4

In Equation 1,

V ₁ is the viscosity (Pa.s) of the suspension introduced into the homogenizing step through the grinding step at a shear rate of 0.1 / s,

V ₂ is the viscosity (Pa.s) of the suspension after one step of homogenization at a shear rate of 0.1 / s, followed by a homogenization step.

In equation 1, V may be a ₁ / V ₂ ≥4, it may be 4≤V ₁ / V ₂ ≤5 or 4 ≤V ₁ / V ₂ ≤4.5. This shows a viscosity that is significantly higher than the application of the grinding unit when the suspension is applied to the grinding unit 10 times and then applied to the homogenizing unit. In other words, even if the homogenization step is performed once, the homogeneous treatment is performed after the grinding step, thereby increasing the viscosity of the suspension. There is a cause for this increase.

After the homogenization step, the suspension is subjected to a filtering step. Specifically, the homogenized suspension is fluid transferred to the filter part, and the concentration of the suspension may be increased by removing the solvent from the suspension.

Specifically, the filtering step may recover the nanocellulose fibers by passing the suspension through the filter. Specifically, the filter unit 140 may be used for both filter press, belt press and centrifugal filtration to separate and recover the cellulose fibers from the suspension. have. In one example, the filter press may be equipped with a filter made of a polymer filter cloth such as polypropylene, the filter may have an air permeability of 0.1 to 10 cm ³ / cm ² / s, more specifically 0.1 To 8 cm ³ / cm ² / s, 0.1 to 6 cm ³ / cm ² / s, 0.1 to 4 cm ³ / cm ² / s, 0.1 to 2 cm ³ / cm ² / s, 0.1 to 1 cm ³ / cm Air permeability of ² / s, 0.2 to 0.8 cm ³ / cm ² / s, 0.3 to 0.7 cm ³ / cm ² / s, 0.4 to 0.6 cm ³ / cm ² / s, or 0.5 cm ³ / cm ² / s Can have. In another example, 20 to 24 filter cloths may be stacked and used. Accordingly, finer nanocellulose fibers can be filtered out.

On the other hand, in another example, it may include a first filter and a second filter. The first filter and the second filter have different pores, so that the nanocellulose fibers can be more easily recovered by the suspension passing through the first filter sequentially passing through the second filter.

On the other hand, the filter portion of the filtering step may be a filter press, in one example, the capacity of the filter press may be 40L / 1 pass, in this case, the pressure provided to the filter press may be 40MPa.

Thereby, the diameter of a nanocellulose fiber is 5 to 60 nm in average, and the fiber with an average deviation of 50 nm or less can be manufactured. More preferably, the nanocellulose fibers produced may be in the range of 5 to 60 nm, in the range of 10 to 50 nm, in the range of 15 to 40 nm, in the range of 16 to 35 nm, or in the range of 20 to 30 nm.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

However, the following Examples and Experimental Examples are only illustrative of the present invention, and the content of the present invention is not limited to the following Examples and Experimental Examples.

< Example >

Example 1 Nanocellulose Fiber Manufacturing

Step 1: Prepare Suspension

A suspension comprising cellulose fibers was prepared in a first storage tank. Specifically, a suspension having a concentration of 0.5% by weight of cellulose fibers obtained by adding raw materials containing cellulose fibers to water was prepared, and the suspension was stirred vigorously at 500 rpm for 20 minutes.

Step 2: Grinding (Grinding)

The suspension obtained in step 1 was fluidly transferred from the first storage tank to the pulverization unit after washing, and the cellulose fiber in the suspension was pulverized in the pulverization unit. At this time, the inner diameter of the grinding unit was 360 mm, the interval between the upper disk and the lower disk in the grinding unit was 24 ㎛. In addition, the disk interval was selected to 24㎛ and the rotational speed was adjusted to 1750 rpm. The procedure was repeated 10 times.

Step 3: Homogenization Step (Homogenizer Treatment)

The suspension, which has passed through the milled part, is fluidly transferred to the first-a storage tank, stirred for 20 minutes in the first-a storage tank, and then passed through a high pressure homogenizer at a pressure of 30,000 psi, where The diameters of the nozzles of the Niiser were 87 μm and 120 μm. The procedure was repeated five times.

Experimental Example

Experimental Example 1. Surface analysis of nanocellulose fibers

1.1 Surface analysis of cellulose fibers

Scanning electron microscopy (SEM) analysis was performed on the cellulose fibers after the second step of Example 1. In this case, the analysis was performed using an FE-SEM analysis equipment (JEOL) at 1.0 kV acceleration voltage, 5.5 mm working distance (WD) and 10.0 k magnification, and the results are shown in FIG. 4. Figure 4 is a morphological picture of the cellulose fibers prepared through the grinding part in the manufacture of nanocellulose fibers ((a) once, (b) three times, (c) five times, (d) seven times, (e) nine times) , (f) 10 passes).

Looking at Figure 4, it was confirmed that the cellulose fibers become denser as the number of times of grinding is increased. However, even though the suspension was pulverized ten times, it was confirmed that the thickness and diameter of the cellulose fibers in the suspension were different.

1-2. Surface Analysis of Nanocellulose Fibers of Examples

Scanning electron microscope (SEM) analysis was performed on the nanocellulose fibers prepared in Example 1. At this time, the analysis was performed using an FE-SEM analysis equipment (JEOL) at 1.0 kV acceleration voltage, working distance (WD) 5.6 mm and magnification 30.0 k, the results are shown in FIG. Figure 5 is a morphological picture of the cellulose fiber prepared through the homogenizing part in the production of the nanocellulose fiber of Example 1 ((a) once, (b) twice, (c) three times, (d) four times, ( e) 5 passes)

Looking at Figure 5, it can be seen that as the number of treatment of homogenization increases, the cellulose fibers become very dense. In particular, even when the suspension which passed the crushing part 10 times was homogenized once, it was confirmed that the diameter of a cellulose fiber is 100 nm or less. In addition, it can be confirmed that the diameter of the fibers in the suspension is uniform.

Experimental Example 2 Particle Size and Standard Deviation of Nanocellulose Fiber

The obtained sample was measured for particle size using the SEM photograph by an image analysis program. Here, the concentration of the suspension is 0.5% by weight. The average diameter and standard deviation results of the cellulose fibers in the suspension prepared according to these conditions are shown in FIG. 6. 6 is a graph showing the diameter and standard deviation of cellulose fibers according to the number of times of grinding and homogenization ((a) average diameter of cellulose fibers, (b) standard deviation of cellulose fiber diameters).

Looking at Figure 6, it can be seen that the diameter and standard deviation of the cellulose fiber is reduced as the number of treatments (1-10 times) of the crushing unit increases. However, when the homogenization of the fiber is not treated, it can be confirmed that the standard deviation is about 140 nm even when the grinding is processed 10 times.

On the other hand, in the case of the embodiment treated with the crushing unit and the homogenizer, the diameter of the cellulose fiber was reduced from about 50nm to 20nm, it was confirmed that the standard deviation of the cellulose fiber is reduced from about 100nm to 20nm.

Although the sample processing capacity (maximum 1000L / hour) of the grinding part (grinder) is advantageous in terms of the processing capacity (maximum 240L / hour) of the homogenizing part (high pressure homogenizer), even if the time consumption increases, the grinding part (grinder) alone It can be seen that treating the sample with a homogenizer (high pressure homogenizer) can make the nanocellulose fibers smaller (particle size) and more even (standard deviation) than used.

Experimental Example 3. Viscosity of suspension

The viscosity of the suspension prepared in Example 1 was measured according to the number of treatments. Viscosity measurements were measured using a rheometer (Rheometer, TA Instruments, USA). The geometry used a cone type of 60 mm in diameter and a slope of 1 ^o , and a shear rate of 0.1 to 100 s ⁻¹ . The results are shown in FIG. 7 is a graph showing the viscosity of the cellulose fibers produced according to the number of treatments of grinding and homogenization (G: grinding, H: homogenization after grinding, number: number of treatments).

Looking at Figure 7, it shows the viscosity of the cellulose suspension shear strain with different application times of grinding and homogenization. In the example, the crushing unit was repeated 10 times, and then the homogenization process was applied five times. Suspension under all conditions decreased in viscosity with increasing shear rate, which showed shear thinning, which is a common poly- and melting phenomenon.

On the other hand, it can be seen that the viscosity of the cellulose suspension is finely reduced as the number of times of application of the grinding unit increases. The cellulose suspension applied to the pulverization part has a difference in viscosity due to cellulose kink in a section with low shear deformation. Longer cellulose lengths increase the kink, resulting in relatively higher viscosities, and shorter kinks reduce the kinetics. Increasing the number of applications of the pulverizer shortens the length of the cellulose, which was microsized, and leads to a reduction in the kink, but does not affect the viscosity change.

Homogenization of cellulosic suspensions results in nanoparticles of cellulose to produce Cellulose nanofiber (CNF) suspensions, which exhibit significantly higher viscosities than milled cellulosic suspensions. This is caused by increasing the particle interactions by reducing the length (particle size) of the cellulose fibers and increasing the number of particles. Increasing the number of application of the grinding unit, the concentration of the CNF suspension is lowered, which is believed to be due to the decrease in the agglomeration of the nanocellulose by increasing the dispersion of the nanocellulose fibers in the suspension.

100: nano cellulose fiber manufacturing apparatus
110: pretreatment unit, first storage tank
111: 1-a storage tank
120: crushing unit
121: first fluid line 122: second fluid line
130: homogenizer
131: second storage tank 132: second 2-a storage tank
133: third fluid line 134: fourth fluid line
135: heat exchanger 136: cooler
140: filter unit

Claims (22)

A pulverizing unit for pulverizing the raw material including cellulose fibers and grinding the average diameter of the cellulose fibers to 60 to 120 nm;
Homogenizing part for homogenizing so that the average diameter of the cellulose fiber passing through the grinding part is 5 to 60 nm; And
Filter unit for filtering the homogenized cellulose fiber to remove the solvent; Nanocellulose fiber manufacturing apparatus comprising a.
The method of claim 1,
Nano cellulose fiber manufacturing apparatus,
Nanocellulose fiber manufacturing apparatus characterized in that it further comprises a pretreatment for pretreating the raw material with an alkaline solution.
The method of claim 1,
The cellulose fiber supplied to the crushing unit is a nanocellulose fiber manufacturing apparatus, characterized in that the suspension state.
The method of claim 1,
Nanocellulose fiber manufacturing apparatus characterized in that the capacity of the prepared nanocellulose fiber is 0.9 to 10 ton / day.
The method of claim 1,
A first storage tank in which a raw material input flow path is formed and which mixes the input raw material and water to produce a suspension;
Grinding unit for grinding the suspension introduced from the first storage tank;
A first fluid line through which the suspension passed through the mill is fluidly moved to the first storage tank;
A second storage tank supplied with a suspension from the first storage tank via the grinding unit;
A second fluid line fluidly connecting the first fluid line and the second storage tank, the suspension fluid passing through the pulverization fluid to the second storage tank;
A homogenizer for homogenizing the suspension introduced from the second storage tank;
A third fluid line through which the suspension, which has been homogenized, is fluidly transferred to a second storage tank;
A filter unit for removing the solvent by filtering the suspension passed through the homogenization unit from the second storage tank; And
A fourth fluid line fluidly connecting the third fluid line to the filter part and supplied with a suspension passed through the homogenization part to the filter part; Nanocellulose fiber manufacturing apparatus comprising a.
The method of claim 5,
The viscosity of the suspension flowing into the second fluid line ranges from 10 to 20 Pa.s at a shear rate of 0.1 / s,
The viscosity of the suspension flowing into the fourth fluid line, nanocellulose fibers manufacturing apparatus, characterized in that in the range of 25 to 80 Pa.s at a shear rate of 0.1 / s.
The method of claim 5,
A first storage tank formed on the first fluid line between the first storage tank and the mill, the first tank containing a suspension flowing out of the mill;
The first-a storage tank,
Apparatus for producing a nanocellulose fiber, characterized in that the suspension supplied to the first storage tank.
The method of claim 5,
A second storage tank formed on the third fluid line between the second storage tank and the homogenizer and containing the suspension flowing out of the homogenizer;
The second 2-a storage tank,
Apparatus for producing a nanocellulose fiber, characterized in that the suspension supplied to the second storage tank.
The method of claim 8,
And a heat exchanger formed on a third fluid line between the homogenizer and the second a-storage tank and supplying heat generated from the suspension discharged from the homogenizer to a cooler.
The method of claim 1,
The crushing unit,
It is a colloid mill (colloid mill) comprising an upper disk and a lower disk,
The interval between the upper disk and the lower disk is nano-cellulose fiber manufacturing apparatus, characterized in that the range of 20 to 40 ㎛.
The method of claim 10,
The upper disk and the lower disk has an average diameter of 300 to 450 mm, nanocellulose fiber manufacturing apparatus, characterized in that for grinding the cellulose fibers at a speed in the range of 200 to 1000 kg / h.
The method of claim 1,
Homogenizer is a high pressure homogenizer comprising a nozzle in the range of 50 to 200 ㎛ average diameter,
When the internal pressure of the high pressure homogenizer is 30,000 psi, nanocellulose fiber manufacturing apparatus, characterized in that for homogenizing the cellulose fiber at a speed in the range of 4 to 4.7L / min.
The method of claim 1,
The filter unit includes a filter made of a polymer filter cloth,
The filter is nanocellulose fabric manufacturing apparatus, characterized in that it has an air permeability of 0.1 to 10 cm ³ / cm ² / s.
Preparing a raw material including cellulose fibers into a suspension, and introducing the suspension into a pulverizing unit to pulverize cellulose fibers in the suspension to an average length of 60 to 120 nm in the pulverizing unit;
Fluidly moving the suspension from the mill to the homogenizer and homogenizing the cellulose fibers in the suspension to an average diameter of 5 to 60 nm; And
Filtering the suspension in a filter portion to remove the solvent from the suspension to increase the concentration of the suspension; Nanocellulose fiber manufacturing method.
The method of claim 14,
The capacity of the nanocellulose fibers produced is
Nanocellulose manufacturing method characterized in that the 0.9 to 10 ton / day.
The method of claim 14,
The raw material containing cellulose fiber,
A method for producing nanocellulose fibers comprising at least one selected from the group consisting of non-wood pulp, conifer pulp, hardwood pulp, unbleached pulp, bleached pulp and deink pulp.
The method of claim 14,
The raw material containing cellulose fiber,
Prepared as a suspension, and further comprising the step of pretreating the suspension by mixing an alkaline solution of 1-10% sodium hydroxide (NaOH) or 1-10% potassium hydroxide (KOH) concentration Fiber manufacturing method.
The method of claim 17,
The concentration of the cellulose fibers contained in the suspension put into the grinding unit,
Nanocellulose fiber manufacturing method, characterized in that 0.1 to 2% by weight.
The method of claim 14,
The step of pulverizing the suspension in the crushing unit, nanocellulose fiber manufacturing method characterized in that it is carried out repeatedly 8 to 15 times.
The method of claim 14,
The homogenization step by adding the suspension to the homogenization unit is performed repeatedly 2 to 10 times,
The internal pressure of the homogenizing part is a nanocellulose fiber manufacturing method, characterized in that in the range of 15,000 to 35,000 psi.
The method of claim 14,
Nanocellulose fiber manufacturing method characterized in that to satisfy the following equation:

[Equation 1]
V ₁ / V ₂ ≥4
In Equation 1,
V ₁ is the viscosity (Pa.s) of the suspension introduced into the homogenizing step through the grinding step at a shear rate of 0.1 / s,
V ₂ is introduced into the homogenizing step at a shear rate of 0.1 / s, and is the viscosity (Pa.s) of the suspension after performing the homogenizing step once.
The method of claim 1,
The filtering step is
A method for producing nanocellulose fibers, characterized in that the homogenized suspension is passed through a filter having an air permeability of 0.1 to 10 cm ³ / cm ² / s.

Images