FIBER-PROCESSING APPARATUS AND FIBER-PROCESSING METHOD

Abstract

A fiber-processing apparatus includes a feed section feeding a dispersion containing liquid and a fibrous material which contains a polysaccharide as a main component and which is dispersed in the liquid and also includes an ejection section ejecting a fluid in which the concentration of the fibrous material is lower than that in the dispersion toward the fed dispersion to crush the fibrous material in the dispersion. The feed section preferably feeds the dispersion vertically downward. Furthermore, the ejection section preferably ejects the fluid downward rather than horizontally.

Description

The present application is based on, and claims priority from JP Application Serial Number 2019-011564, filed Jan. 25, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a fiber-processing apparatus and a fiber-processing method.

2. Related Art

Attempts have been made to manufacture cellulose nanofibers by fibrillating cellulose fibers.

For example, JP-A-2005-270891 discloses a method in which a dispersion of a polysaccharide is ejected from a pair of nozzles at a high pressure of 70 MPa to 250 MPa and jet flows thereof are allowed to collide with each other such that the polysaccharide is crushed. In this method, the average width of particles can be reduced to 10 μm or less in such a manner that a dispersion with a cellulose concentration of 1% by mass is repeatedly crushed a plurality of times.

However, in the method disclosed in JP-A-2005-270891, the dispersion needs to be ejected at high pressure and the ejection of the dispersion needs to be repeated a plurality of times. Therefore, the viscosity and fluidity of the dispersion needs to be taken into account and the concentration of the dispersion cannot be sufficiently raised. Thus, there is a problem in that the amount of the polysaccharide that can be processed per unit time is limited and the processing efficiency thereof cannot be sufficiently raised.

SUMMARY

The present disclosure has been made to solve at least one portion of the above problem and can be embodied as described below.

A fiber-processing apparatus according to the present disclosure includes a feed section feeding a dispersion containing liquid and a fibrous material which contains a polysaccharide as a main component and which is dispersed in the liquid and also includes an ejection section ejecting a fluid in which the concentration of the fibrous material is lower than that in the dispersion toward the fed dispersion to crush the fibrous material in the dispersion.

A fiber-processing method according to the present disclosure includes ejecting fluid toward a dispersion containing liquid and a fibrous material which contains a polysaccharide as a main component and which is dispersed in the liquid to crush the fibrous material in the dispersion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of a fiber-processing apparatus according to a first embodiment of the present disclosure.

FIG. 2 is a horizontal sectional view of the fiber-processing apparatus shown in FIG. 1.

FIG. 3 is a side view selectively showing ejection nozzles included in the fiber-processing apparatus shown in FIG. 1.

FIG. 4 is a schematic sectional view of a fiber-processing apparatus according to a second embodiment of the present disclosure.

FIG. 5 is a schematic sectional view of a fiber-processing apparatus according to a third embodiment of the present disclosure.

FIG. 6 is a horizontal sectional view of the fiber-processing apparatus shown in FIG. 5.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Preferred embodiments of the present disclosure are described below in detail with reference to the attached drawings.

Fiber-Processing Apparatus

First Embodiment

A fiber-processing apparatus 1 according to a first embodiment of the present disclosure is described.

FIG. 1 is a schematic sectional view of the fiber-processing apparatus 1. FIG. 2 is a horizontal sectional view of the fiber-processing apparatus 1.

As shown in FIG. 1, the fiber-processing apparatus 1 includes a cylindrical body 2 extending in a vertical direction, a feed section 3 feeding a dispersion 34 containing a fibrous material 32 to the cylindrical body 2, an ejection section 4 ejecting fluid 42 toward the fed dispersion 34 to crush the fibrous material 32 in the dispersion 34, and a collection section 5 collecting fine fibers after crushing.

According to the fiber-processing apparatus 1, even though the dispersion 34, which has relatively high concentration, is used, the fibrous material 32 can be efficiently disintegrated and the fine fibers can be obtained. Therefore, the amount of the fibrous material 32 that can be processed per unit time can be increased and the fiber-processing apparatus 1, which has high processing efficiency, can be achieved. The fine fibers are contained in a collected mixture 52 in high concentration and therefore there is an advantage in that the energy required to dry the mixture 52 can be reduced.

Components of the fiber-processing apparatus 1 are described below in detail.

As shown in FIGS. 1 and 2, the cylindrical body 2 is a cylinder having an axis parallel to the vertical direction.

Examples of material forming the cylindrical body 2 include metal materials, ceramic materials, and resin materials.

The upper end of the cylindrical body 2 is provided with the feed section 3. As shown in FIGS. 1 and 2, the feed section 3 includes a storage portion 30 storing the dispersion 34 and a discharge portion 31 placed at the lower end of the storage portion 30.

The storage portion 30 is substantially a conical cylinder which has an axis parallel to the vertical direction and of which the bottom is located above the vertex thereof.

The discharge portion 31 is a lower opening of the storage portion 30 and is located at the lower end of the storage portion 30. Since the storage portion 30 has substantially a conical shape as described above, the inside diameter of the discharge portion 31 is less than the inside diameter of the storage portion 30. Therefore, when the dispersion 34 is stored in the storage portion 30, the flow rate of the stored dispersion 34 is regulated in the discharge portion 31. Thus, the dispersion 34 gradually accumulates from the discharge portion 31 and the dispersion 34 can be allowed to naturally fall from the discharge portion 31 with the flow rate thereof regulated. This enables the dispersion 34 to be fed to the cylindrical body 2 in a target feed amount or at a target feed rate.

The discharge portion 31 may be provided with a valve varying the inside diameter thereof or the like as required. This enables the flow rate to be varied any time. The storage portion 30 may be provided with a stirrer stirring the dispersion 34 or the like as required.

The feed of the dispersion 34 from the feed section 3 may be forcibly performed using a pump or the like and is preferably performed by means of the free fall of the dispersion 34 as described above. That is, the feed section 3 is preferably configured such that the dispersion 34 is fed vertically downward. This enables the dispersion 34 to be continuously fed without consuming a large amount of energy. Since the feed amount or feed rate of the dispersion 34 can be adjusted by adjusting the fluidity of the dispersion 34, the inside diameter of the discharge portion 31, and the like, the certain feed amount or certain feed rate of the dispersion 34 can be readily set. Therefore, the configuration of the fiber-processing apparatus 1 can be simplified.

In addition, the dispersion 34 is fed so as to fall in a space in the cylindrical body 2. Therefore, when the fluid 42 is ejected toward the dispersion 34 as described below, the fluid 42 can be ejected on four sides of the dispersion 34 in all directions. That is, the ejection section 4 is configured such that the fluid 42 is ejected toward the falling dispersion 34 in three directions as described below. This enables high energy to be efficiently supplied to the fibrous material 32 in the dispersion 34 in a short time and enables the capacity to crush the fibrous material 32 per unit time to be raised.

The dispersion 34 contains the fibrous material 32 and liquid 33 that is a dispersion medium dispersing the fibrous material 32.

The fibrous material 32 contains a polysaccharide as a main component and is a substance in a fibrous form. Examples of the polysaccharide include cellulose, chitin, chitosan, starch, pullulan, carrageenan, agar, curdlan, furcellaran, xanthan gum, guar gum, gum arabic, schizophyllan, hyaluronic acid, alginic acid, sodium alginate, pectin, welan gum, and derivatives of these.

In particular, the polysaccharide is preferably cellulose. Cellulose is a polysaccharide obtained from botanical biomass. That is, cellulose is a polysaccharide that can be produced from a plant which is a regenerative source. Fine fibers such as cellulose nanofibers and cellulose nanocrystals obtained by disintegrating cellulose combine low density and high modulus of elasticity. Therefore, fine fibers obtained by crushing the fibrous material 32, which contains cellulose as a main component, take advantage of low density and high modulus of elasticity and are used as materials useful for filler added to, for example, a resin material.

The term “main component” refers to a component that accounts for 50% by mass or more of the fibrous material 32.

Examples of cellulose derivatives that are derivatives of cellulose alone include methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, acetylcellulose, nitrocellulose, and carboxymethylnitrocellulose. The cellulose derivatives include crystalline celluloses.

The liquid 33 is not particularly limited and may be liquid capable of dispersing the fibrous material 32. Examples of the liquid 33 include waters such as tap water, pure water, ion-exchanged water, and recycled water; alcohols such as methanol, ethanol, and propanol; and ketones such as acetone. The liquid 33 may be, for example, a mixed liquid containing these, an aqueous solution of alcohol, or the like.

In addition, the dispersion 34 may contain an arbitrary additive. Examples of the additive include a dispersant, a surfactant, a preservative, a fungicide, a thickening agent, an aggregation inhibitor, an antifoaming agent, a leveling agent, a humectant, an oxidation inhibitor, an ultraviolet absorber, and a pH adjustor.

The fibrous material 32 is preferably a fibrillated product of a starting material or a fibrillated product of a processed product of the starting material. The fibrillation state of the fibrous material 32, which is fed to the fiber-processing apparatus 1, can be homogenized in such a manner that after the starting material or the processed product thereof is fibrillated into the fibrillated product, the fibrillated product is used as the fibrous material 32. Therefore, in the fiber-processing apparatus 1, fine fibers can be manufactured in such a manner that the fibrous material 32 is efficiently crushed.

The size of the fibrous material 32 is not particularly limited and is preferably such that the fiber width of monofilaments is 20 μm to 30 μm and the fiber length thereof is 1 mm to 3 mm. The fibrous material 32 having such a size is obtained by fibrillating the starting material or the processed product thereof in a relatively simple manner and is, therefore, useful as a fibrous material fed to the fiber-processing apparatus 1.

The fiber width of the above-mentioned monofilaments is determined in the form of the average fiber width of ten or more of the monofilaments extracted at random on an image observed with, for example, a scanning electron microscope. Likewise, the fiber length of the monofilaments is determined in the form of the average fiber length of ten or more of the monofilaments extracted at random on an image observed with, for example, a scanning electron microscope.

The starting material is not particularly limited and may contain the polysaccharide. Examples of the processed product include those obtained by subjecting the starting material to an arbitrary treatment such as a mechanical treatment like, for example, cutting or a chemical treatment like contact with a chemical.

The concentration of the fibrous material 32 in the dispersion 34 is not particularly limited and may be such a concentration that the dispersion 34 has fluidity so as to be capable of being fed from the feed section 3. The concentration of the fibrous material 32 in the dispersion 34 is preferably 10% by mass or more, more preferably 15% by mass to 50% by mass, and further more preferably 20% by mass to 40% by mass. Setting the concentration of the fibrous material 32 in the dispersion 34 within the above range ensures such fluidity that the dispersion 34 flows to some extent and also enables the amount of the fibrous material 32 capable of being fed from the feed section 3 per unit time to be ensured. This enables both the good handleability of the dispersion 34 and the high manufacturing efficiency of the fine fibers obtained by crushing the fibrous material 32 to be achieved.

When the concentration of the fibrous material 32 is below the lower limit, the amount of the fibrous material 32 capable of being fed per unit time is small and therefore the amount of the fine fibers obtained per unit time is small; hence, the manufacturing efficiency may possibly be low. However, when the concentration of the fibrous material 32 is above the upper limit, the fluidity of the dispersion 34 is low. Therefore, it is difficult to smoothly feed the dispersion 34 from the feed section 3, the concentration of the dispersion 34 is nonuniform, and the degree of crushing of the fibrous material 32 may possibly be nonuniform.

The amount of the dispersion 34 fed per unit time is preferably, but is not limited to, 10 g/min to 500 g/min and more preferably 30 g/min to 300 g/min. Feeding the dispersion 34 in such a feed amount sufficiently raises the efficiency of crushing and enables uniform crushing. That is, when the feed amount is below the lower limit, the efficiency of crushing may possibly be low. However, when the feed amount is above the upper limit, uniform crushing may possibly be difficult depending on the concentration of the fibrous material 32 in the dispersion 34.

As shown in FIGS. 1 and 2, the ejection section 4 includes a fluid storage portion 44 storing the fluid 42; a pump 46 pumping out the fluid 42 stored in the fluid storage portion 44; and ejection nozzles 48 ejecting the fluid 42, discharged from the pump 46, toward the inside of the cylindrical body 2. The ejection nozzles 48 are connected to the fluid storage portion 44 with a pipe 47. The pump 46 is placed halfway through the pipe 47.

The ejection nozzles 48 regulate the ejection direction of the fluid 42 discharged from the pump 46 through the pipe 47. In this embodiment, when the dispersion 34 falls freely from the feed section 3, the fluid 42 is ejected toward the falling dispersion 34 obliquely downward at high velocity. This allows the fluid 42 to collide with the dispersion 34 to generate high collision energy. The fibrous material 32 in the dispersion 34 is crushed by the collision energy, whereby the fine fibers are obtained.

The fluid 42 is not particularly limited and may be one in which the concentration of the fibrous material 32 is lower than that in the dispersion 34. The state of the fluid 42 is liquid or solid or may be a liquid-solid mixture state.

In particular, the fluid 42 used is preferably liquid and more preferably a liquid having the same composition as that of the liquid contained in the dispersion 34. This allows the fluid 42 to be readily handled and enables the occurrence of separation due to a difference in density or separation due to low compatibility to be prevented when a mixture of the dispersion 34 and the fluid 42 is collected.

The fluid 42 used is particularly preferably water or liquid including alcohols. These liquids are relatively inexpensive, are unlikely to modify the fibrous material 32, and are therefore particularly useful as the fluid 42.

Examples of the alcohols include methanol, ethanol, and propanol.

When the fluid 42 is solid, examples of the fluid 42 include ice and dry ice.

The concentration of the fibrous material 32 in the fluid 42 may be lower than the concentration of the fibrous material 32 in the dispersion 34 as described above. The difference between these concentrations is preferably 1.0% by mass or more and more preferably 10% by mass or more. This enables both the increase in concentration of the dispersion 34 and the adaptability of the fluid 42 to high-velocity ejection to be achieved.

The concentration of solid matter including the fibrous material 32 in the fluid 42 is preferably 1.0% by mass or less, more preferably 0.10% by mass or less, and further more preferably 0% by mass. This concentration sufficiently reduces the viscosity of the fluid 42 and enables the fluidity thereof to be sufficiently raised. Therefore, the fluid 42 can be ejected at high velocity.

As described above, the fiber-processing apparatus 1 includes the feed section 3, which feeds the dispersion 34 in which the fibrous material 32 containing the polysaccharide as a main component is dispersed in liquid, and the ejection section 4, which ejects the fluid 42 in which the concentration of the fibrous material 32 is lower than that in the dispersion 34 toward the fed dispersion 34 to crush the fibrous material 32 in the dispersion 34.

According to the fiber-processing apparatus 1, even though the dispersion 34, which has relatively high concentration as described above, is used, the fibrous material 32 can be efficiently disintegrated and the fine fibers can be obtained. Therefore, the amount of the fibrous material 32 that can be processed per unit time can be increased and the fiber-processing apparatus 1, which has high processing efficiency, can be achieved. Since the fine fibers are contained in the collected mixture 52 in high concentration, there is an advantage in that the energy required to dry the mixture 52 can be reduced.

It is not necessary to repeat a process in which a dispersion is ejected at high pressure to collide a plurality of times as before. Therefore, a mechanism that circulates the dispersion or a mechanism that stores a large amount of the dispersion is unnecessary and the configuration of the fiber-processing apparatus 1 can be simplified. Continuous processing is possible and therefore, from this viewpoint, the manufacturing efficiency of the fine fibers can be enhanced.

Furthermore, in a case where a dispersion containing a large amount of a fibrous material is ejected at high pressure as before, there are problems that the wear of an ejection mechanism and clogging due to the fibrous material are likely to occur with the increase in ejection velocity of the dispersion. In consideration of these problems, it is difficult to eject the dispersion at high pressure and high velocity.

However, in this embodiment, the dispersion 34, which contains the fibrous material 32 in high concentration, is not ejected but the fluid 42, in which the concentration of the fibrous material 32 is low, is ejected at high velocity. Therefore, the concentration of the fluid 42 can be set to such a low level as described above. This enables the occurrence of failures such as the wear of the ejection nozzles 48 and the clogging of the pump 46 due to the fibrous material 32 to be suppressed.

The ejection section 4 may eject the fluid 42 in a horizontal direction or upward rather than horizontally and preferably ejects the fluid 42 downward rather than horizontally as shown in FIG. 1. Ejecting the fluid 42 downward rather than horizontally as described above allows the mixture 52, which is composed of the dispersion 34 and the fluid 42, to remain in a lower portion because of the momentum of the fluid 42. This enables the continuous collision of the dispersion 34 with the fluid 42.

FIG. 3 is a side view selectively showing the ejection nozzles 48, which are included in the fiber-processing apparatus 1 as shown in FIG. 1.

As shown in FIGS. 2 and 3, the number of the ejection nozzles 48, which are included in the ejection section 4, is three. As shown in FIG. 2, the three ejection nozzles 48 are spaced at equal intervals of 120° and are placed on the same level in a vertical direction. The fluid 42 ejected from each ejection nozzle 48 is preset so as to fly obliquely downward to concentrate at a collision point C. The collision point C is located in the fall path of the dispersion 34. Therefore, the fluid 42 collides with the dispersion 34 at the collision point C, thereby enabling high collision energy to be applied to the fibrous material 32.

Referring to FIG. 3, the angle formed by the ejection direction of the fluid 42 the horizontal plane HP is represented by θ1. The angle θ1 is preferably 0° to less than 90°, more preferably 10° to 75°, and further more preferably 30° to 60°. Setting the angle θ1 within the above range sufficiently ensures the relative velocity of the colliding fluid 42 and enables the mixture 52, which is composed of the dispersion 34 and the fluid 42, to be efficiently sent downward after collision. That is, both the promotion of disintegration due to sufficient relative velocity and the sending of a mixture suitable for continuous processing can be achieved.

Referring to FIG. 3, the distance from the tip of each ejection nozzle 48 to the collision point C is represented by L1. The distance L1 is appropriately set depending on the ejection velocity of the fluid 42 or the amount of the fluid 42 ejected per unit time. The distance L1 is preferably, for example, 5 mm to 30 cm and more preferably 1 cm to 10 cm. This enables the fibrous material 32 to be more efficiently crushed.

The number of the ejection nozzles 48 is not particularly limited and may be one or two or more. In consideration of more uniform crushing, the number of the ejection nozzles 48 is preferably two or more.

When the number of the ejection nozzles 48 is two or more, the angle between the ejection nozzles 48 is represented by θ2 as shown in FIG. 2. The angle θ2 is appropriately set depending on the number of the ejection nozzles 48. The angle θ2 is preferably, for example, 10° to 180° and more preferably 20° to 150°. This optimizes the intervals between the ejection nozzles 48, thereby enabling more uniform crushing.

The ejection pressure of the fluid 42 is preferably 100 MPa to 600 MPa and more preferably 200 MPa to 500 MPa. Ejecting the fluid 42 at such high pressure enables the fluid 42 to be ejected at extremely high velocity depending on the bore of the ejection nozzles 48. Therefore, the kinetic energy of the fluid 42 is high and very high collision energy can be applied to the fibrous material 32 by the collision of the fluid 42 with the dispersion 34. This enables the fibrous material 32 to be finely crushed even by single collision.

Furthermore, since the ejection velocity is high, a change in pressure is likely to occur and a large number of bubbles are likely to be generated. When the bubbles disappear, high pressure is instantaneously applied to the fibrous material 32. This phenomenon is called cavitation erosion. Using this phenomenon enables the fibrous material 32 to be more efficiently crushed.

As shown in FIG. 1, the cylindrical body 2 is provided with a vent 22 for relieving the pressure in the cylindrical body 2. The vent 22 may be, for example, a normally open channel or a relief valve that is opened or closed as required. The presence of the vent 22 enables the fluid 42 to be ejected without a hitch.

The vent 22 may be placed as required. In a case where the pressure can be relieved from, for example, the lower end of the cylindrical body 2, the vent 22 may be omitted.

The ejection velocity of the fluid 42 is preferably Mach 1.0 or more and more preferably Mach 1.2 or more. At such an ejection velocity, shock waves can be generated around the fluid 42. The shock waves efficiently compress bubbles generated around the fibrous material 32, thereby enabling high pressure to be applied to the fibrous material 32 by the rupture of the bubbles. Therefore, the fibrous material 32 can be more efficiently crushed.

The ejection velocity (Mach number) of the above-mentioned fluid 42 is the ratio of the velocity thereof to the speed (340 m/s) of sound in air.

Furthermore, the amount of the fluid 42 ejected per unit time is preferably, but is not limited to, 10 g/min to 500 g/min and more preferably 30 g/min to 300 g/min. Ejecting the fluid 42 in such an amount sufficiently raises the efficiency of crushing and enables uniform crushing. That is, when the amount of the ejected fluid 42 is below the lower limit, the efficiency of crushing may possibly be low. However, when the amount of the ejected fluid 42 is above the upper limit, uniform crushing may possibly be difficult depending on the concentration of the fibrous material 32 in the dispersion 34.

In the ejection section 4, which is as described above, ejection conditions of the fluid 42 ejected from the three ejection nozzles 48 may be different from each other and are preferably the same as each other. When the ejection conditions are the same as each other, fine fibers having uniform fiber characteristics can be manufactured.

The collection section 5 is located at the lower end of the cylindrical body 2. As shown in FIGS. 1 and 2, the collection section 5 includes a vessel for storing the mixture 52, which is composed of the dispersion 34 and fluid 42, falling in the cylindrical body 2.

A pipe or the like for returning the mixture 52 to the feed section 3 again may be connected to the collection section 5 as required. The presence of the pipe enables the mixture 52 to be subjected to crushing again as described above.

The collection section 5 may be provided with a separator separating fine fibers contained in the mixture 52 as required. The separator is, for example, a filtration device filtering out the fine fibers or the like.

In the mixture 52, which is composed of the dispersion 34 and fluid 42, collected in the collection section 5, the concentration of the fibrous material 32 in the mixture 52 is preferably 10% by mass or more, more preferably 15% by mass to 50% by mass, and further more preferably 20% by mass to 40% by mass as calculated from the amount of the dispersion 34 fed per unit time and the amount of the fluid 42 ejected per unit time. Setting the concentration of the fibrous material 32 in the mixture 52 within the above range enables the mixture 52 to be collected in a liquid state in high concentration. Therefore, the fluidity of the mixture 52 is ensured to a certain extent, the handling of the mixture 52 is easy, and the energy necessary for the operation of taking the fine fibers out of the mixture 52 or the operation of removing liquid from the mixture 52 can be reduced. As a result, the processing efficiency of the fiber-processing apparatus 1 can be further raised.

Second Embodiment

Next, a fiber-processing apparatus 1 according to a second embodiment of the present disclosure is described.

FIG. 4 is a schematic sectional view of the fiber-processing apparatus 1.

The second embodiment is described below with a focus on differences from the first embodiment. Similar matters are not described in detail.

The second embodiment is similar to the first embodiment except that the arrangement of three ejection nozzles 48 is different from that in the first embodiment.

In the first embodiment, the three ejection nozzles 48 are placed on the same level in the vertical direction and are spaced at equal intervals of 120°. However, in this embodiment, as shown in FIG. 4, the three ejection nozzles 48 are placed so as to lie on a straight line parallel to the vertical direction. That is, in this embodiment, the three ejection nozzles 48 are different in level from each other in the vertical direction and are placed so as to overlap at the same position when viewed in the vertical direction.

According to this embodiment, effects similar to those described in the first embodiment are provided and a dispersion 34 can receive collision energy from fluid 42 three times because the three ejection nozzles 48 are different in level from each other in the vertical direction. That is, in the first embodiment, the dispersion 34 and the fluid 42 collide at the single collision point C. However, in this embodiment, a plurality of collision points C are present. Therefore, the collision frequency of the dispersion 34 and the fluid 42 can be adjusted depending on the number of the collision points C. As a result, the degree of crushing of a fibrous material 32 can be controlled, thereby enabling fine fibers with a target size to be efficiently manufactured.

The intervals between the ejection nozzles 48 in the vertical direction may be the same as or different from each other in individual intervals. The number of the ejection nozzles 48 may be two or four or more.

Third Embodiment

Next, a fiber-processing apparatus 1 according to a third embodiment of the present disclosure is described.

FIG. 5 is a schematic sectional view of the fiber-processing apparatus 1. FIG. 6 is a horizontal sectional view of the fiber-processing apparatus 1.

The third embodiment is described below with a focus on differences from the second embodiment. Similar matters are not described in detail.

The third embodiment is similar to the second embodiment except that the arrangement of three ejection nozzles 48 is different from that in the second embodiment.

In the second embodiment, the three ejection nozzles 48 are different in level from each other in the vertical direction and are placed so as to overlap at the same position when viewed in the vertical direction. However, in this embodiment, as shown in FIG. 5, the three ejection nozzles 48 are different in level from each other in the vertical direction and are placed so as to be seen at different positions when viewed in the vertical direction.

In particular, as shown in FIG. 6, two of the three ejection nozzles 48 are placed at opposite positions with a collision point C therebetween when viewed in the vertical direction.

According to this embodiment, effects similar to those described in the second embodiment are provided and collision energy can be applied to a falling dispersion 34 in a spatially unbiased manner. As a result, biasing the degree of crushing is reduced, thereby enabling fine fibers with a uniform size to be manufactured.

The intervals between the ejection nozzles 48 in the vertical direction may be the same as or different from each other in individual intervals. The number of the ejection nozzles 48 may be two or four or more.

Fiber-Processing Method

Next, a method for processing a fibrous material 32 using the fiber-processing apparatus 1 shown in one of FIGS. 1 to 3, that is, a fiber-processing method according to an embodiment of the present disclosure is described below.

The fiber-processing method is one in which the dispersion 34 is dropped from the feed section 3, the fluid 42 is ejected from the ejection section 4 toward the falling dispersion 34, and the fibrous material 32 in the dispersion 34 is crushed.

In particular, the dispersion 34 is stored in the storage portion 30 of the feed section 3. The stored dispersion 34 is dropped from the discharge portion 31 into the cylindrical body 2. This generates a flow of the continuously falling dispersion 34.

The fluid 42 is ejected from the ejection section 4 toward the flow of the dispersion 34 at high velocity. The ejected fluid 42 collides with the dispersion 34, whereby the fibrous material 32 is crushed by the impact thereof, that is, the kinetic energy. The crushing of the fibrous material 32 is facilitated by the disappearance of bubbles generated by the collision or a shock wave. As a result, the fibrous material 32 is efficiently crushed, thereby enabling the fine fibers to be obtained. The processed dispersion 34 is recovered together with the fluid 42 in the form of the mixture 52. The fine fibers are taken of the mixture 52, thereby enabling the fine fibers alone to be collected.

The size of the fine fibers, which are collected as described above, is not particularly limited and is preferably such that, for example, the fiber width of monofilaments is 1 nm to 500 nm and the fiber length of the monofilaments is 1 μm or more. The fine fibers can be used in applications such as, for example, filler materials added to polymeric materials including resins, aerogel materials, and optically anisotropic materials.

The fiber width of the above-mentioned monofilaments is determined in the form of the average fiber width of ten or more of the monofilaments extracted at random on an image observed with, for example, a scanning electron microscope. Likewise, the fiber length of the monofilaments is determined in the form of the average fiber length of ten or more of the monofilaments extracted at random on an image observed with, for example, a scanning electron microscope.

The dispersion 34 may be crushed once or may be crushed a plurality of times. In this operation, the unprocessed dispersion 34 and the processed dispersion 34 may be mixed together.

As described above, the fiber-processing method is such that the fluid 42 is ejected toward the dispersion 34, in which the fibrous material 32 containing the polysaccharide as a main component is dispersed in the liquid 33, and the fibrous material 32 in the dispersion 34 is crushed.

According to the fiber-processing method, even though the dispersion 34, which has relatively high concentration, is used, the fibrous material 32 can be efficiently disintegrated and the fine fibers can be obtained. Therefore, the amount of the fibrous material 32 that can be processed per unit time can be increased and the processing efficiency can be raised.

It is not necessary to repeat a process in which a dispersion is ejected at high pressure to collide a plurality of times as before. Therefore, the processing time can be reduced. From this viewpoint, the processing efficiency can be raised.

A fiber-processing apparatus and fiber-processing method according to the present disclosure have been described above in the illustrated embodiments. The present disclosure is not limited to the embodiments. For example, sections forming the fiber-processing apparatus may be replaced with those having an arbitrary configuration capable of exhibiting a similar function. An arbitrary component may be added to the fiber-processing apparatus. Furthermore, an arbitrary target step may be added to the fiber-processing method in the embodiments.

EXAMPLES

Next, examples of the present disclosure are described in detail.

(1) Manufacture of Fine Fibers

Example 1

First, a fibrous material was prepared. The fibrous material was leaf bleached kraft pulp. Liquid was prepared to disperse the fibrous material. The liquid was water. The fibrous material and the liquid were mixed together, whereby a dispersion with a fibrous material concentration of 30% by mass was prepared.

Next, a fiber-processing apparatus was prepared as shown in FIG. 1. The dispersion was charged into a feed section thereof. The charged dispersion continuously fell under its own weight into a cylindrical body.

Subsequently, water, which was fluid, was ejected from an ejection section. The ejected water was allowed to collide with the falling dispersion, so that the leaf bleached kraft pulp was crushed, whereby a mixture containing fine cellulose fibers was obtained. Incidentally, ejection conditions of water are as shown in the table.

The obtained mixture was collected in a collection section.

Examples 2 and 3

A mixture containing fine cellulose fibers was collected in substantially the same manner as that used in Example 1 except that the angle Al was varied as shown in the table as ejection conditions of fluid.

Example 4

A mixture containing fine cellulose fibers was collected in substantially the same manner as that used in Example 1 except that the ejection pressure was varied as shown in the table and the ejection velocity (Mach number) was varied as shown in the table as ejection conditions of fluid.

Example 5

A mixture containing fine cellulose fibers was collected in substantially the same manner as that used in Example 1 except that feed conditions of a dispersion were varied as shown in the table.

Example 6

A mixture containing fine cellulose fibers was collected in substantially the same manner as that used in Example 1 except that fluid was changed from water to an aqueous solution of ethanol with a concentration of 10% by mass as ejection conditions of fluid.

Examples 7 and 8

A mixture containing fine cellulose fibers was collected in substantially the same manner as that used in Example 1 except that the number of ejection nozzles and the ejection pressure were varied as shown in the table as ejection conditions of fluid.

Example 9

A mixture containing fine cellulose fibers was collected in substantially the same manner as that used in Example 1 except that an apparatus shown in FIG. 4 was used as a fiber-processing apparatus.

Example 10

A mixture containing fine cellulose fibers was collected in substantially the same manner as that used in Example 1 except that an apparatus shown in FIG. 5 was used as a fiber-processing apparatus.

Comparative Example

Dropping a dispersion from a feed section was omitted. Dispersions with a fibrous material concentration of 5% by mass were used instead of water. The dispersions were allowed to collide with each other. An obtained mixture was collected. That is, a dispersion and water (fluid) were not allowed to collide with each other but dispersions with the same concentration were allowed to collide with each other.

Various conditions in the above examples and comparative example are shown in the table.

(2) Evaluation

(2-1) Size of Fine Cellulose Fibers

The fine cellulose fibers collected in each of the examples and the comparative example were observed with a scanning electron microscope. The fiber width of monofilaments of the fine cellulose fibers was measured. Thereafter, measurement results were evaluated in accordance with evaluation standards below.

Evaluation Standards for Size of Fine Cellulose Fibers

A: The fiber width of fine cellulose fibers is 20 nm or less.

B: The fiber width of fine cellulose fibers is more than 20 nm to 100 nm.

C: The fiber width of fine cellulose fibers is more than 100 nm.

Evaluation results obtained as described above are shown in the table.

(2-2) Concentration of Mixture Containing Fine Cellulose Fibers

Next, the concentration of the fine cellulose fibers collected in each of the examples was measured. Measurement results are shown in the table.

TABLE
	Conditions of fiber-processing apparatus	Evaluation results
		Feed conditions of	Ejection conditions of fluid		Concentration
		dispersion				Ejection			of fine
		Concentration			Number of		velocity		Size of fine	cellulose
		of fibrous	Feed per		ejection	Angle	(Mach	Ejection	cellulose	fibers in
	Apparatus	material	unit time	Fluid	nozzles	θ1	number)	pressure	fibers	mixture
	—	Mass percent	g/min	—	—	Degrees	—	MPa	—	Mass percent
Example 1	FIG. 1	30	100	Water	3	45	1.2	350	A	15
Example 2	FIG. 1	30	100	Water	3	30	1.2	350	A	15
Example 3	FIG. 1	30	100	Water	3	60	1.2	350	A	15
Example 4	FIG. 1	30	100	Water	3	45	0.8	250	B	15
Example 5	FIG. 1	40	100	Water	3	45	1.2	250	A	20
Example 6	FIG. 1	30	100	Aqueous	3	45	1.2	350	A	15
				solution of
				ethanol
Example 7	FIG. 1	30	100	Water	2	45	1.2	230	A	22
Example 8	FIG. 1	30	100	Water	1	45	1.2	115	B	25
Example 9	FIG. 4	30	100	Water	3	45	1.2	350	A	15
Example 10	FIG. 5	30	100	Water	3	45	1.2	350	A	15
Comparative	—	Dispersions with a fibrous material concentration of 5% by mass were allowed to	A	5
Example		collide with each other.

As is clear from the table, in the examples, the fine cellulose fibers, which were sufficiently disintegrated, could be manufactured by single crushing.

The concentration of the fine cellulose fibers in the mixture collected in each example is shown in the table.

As shown in the table, the concentration of the fine cellulose fibers in the mixture collected in each example was high, 10% by mass or more. Thus, according to the present disclosure, it was recognized that a mixture containing fine fibers in high concentration could be collected even by a little crushing.

Incidentally, a mixture containing fine fibers was obtained in substantially the same manner as that used in the example except that a deproteinized, demineralized chitin-containing biological material was used instead of leaf bleached kraft pulp. The obtained fine fibers were such fine chitin fibers that monofilaments had a fiber width of 20 nm or less and a fiber length of 5 μm or more. Thus, the present disclosure is applicable to the manufacture of the fine chitin fibers.

Claims

1. A fiber-processing apparatus comprising:

a feed section feeding a dispersion containing liquid and a fibrous material which contains a polysaccharide as a main component and which is dispersed in the liquid; and

an ejection section ejecting a fluid in which the concentration of the fibrous material is lower than that in the dispersion toward the fed dispersion to crush the fibrous material in the dispersion.

2. The fiber-processing apparatus according to claim 1, wherein the feed section feeds the dispersion vertically downward.

3. The fiber-processing apparatus according to claim 2, wherein the ejection section ejects the fluid toward the falling dispersion.

4. The fiber-processing apparatus according to claim 2, wherein the ejection section ejects the fluid downward rather than horizontally.

5. The fiber-processing apparatus according to claim 1, wherein the fluid is a liquid having the same composition as that of the liquid in the dispersion and includes water or alcohols.

6. The fiber-processing apparatus according to claim 5, wherein the concentration of the fibrous material in a mixture of the dispersion and the fluid is 10% by mass or more as calculated from the amount of the dispersion fed per unit time and the amount of the fluid ejected per unit time.

7. The fiber-processing apparatus according to claim 1, wherein the ejection pressure of the fluid is 100 MPa to 600 MPa.

8. The fiber-processing apparatus according to claim 1, wherein the ejection velocity of the fluid is Mach 1.0 or more.

9. The fiber-processing apparatus according to claim 1, wherein the concentration of the fibrous material in the dispersion is 10% by mass or more.

10. The fiber-processing apparatus according to claim 1, wherein the polysaccharide is cellulose.

11. The fiber-processing apparatus according to claim 1, wherein the fibrous material is a fibrillated product.

12. The fiber-processing apparatus according to claim 1, wherein the size of the fibrous material is such that the fiber width of monofilaments is 20 μm to 30 μm and the fiber length thereof is 1 mm to 3 mm.

13. A fiber-processing method comprising ejecting fluid toward a dispersion containing liquid and a fibrous material which contains a polysaccharide as a main component and which is dispersed in the liquid to crush the fibrous material in the dispersion.