JP6925315B2 - Method for producing pulp fiber for medium, pulp fiber for medium, and use of pulp fiber for medium - Google Patents

Description

The present disclosure discloses a method for producing pulp fiber for a medium as a medium for a cellulase-producing bacterium, a pulp fiber for a medium as a medium for a cellulase-producing bacterium, and a medium for a cellulase-producing bacterium derived from a used sanitary product containing the pulp fiber. With respect to the use of pulp fibers for media as a cellulase for the production of cellulase.

Technology for recycling used sanitary goods such as disposable diapers is being studied.
For example, Patent Document 1 discloses a method for producing recycled pulp fiber that can be mainly reused as a sanitary product. Specifically, Patent Document 1 describes a method of recovering pulp fibers from used sanitary products containing pulp fibers and a highly water-absorbent polymer to produce recycled pulp that can be reused as sanitary products. The method is to apply a physical force to the used sanitary goods in an aqueous solution containing polyvalent metal ions or an acidic aqueous solution having a pH of 2.5 or less. A step of decomposing pulp fibers into other materials, a step of separating pulp fibers from a mixture of pulp fibers and other materials produced in the decomposition step, and an ozone-containing aqueous solution having a pH of 2.5 or less. A method is described which comprises a step of processing in.

In Patent Document 1, the reason for treating pulp fibers with an ozone-containing aqueous solution is that not a little superabsorbent polymer remains in the separated pulp fibers, and the superabsorbent polymer is oxidatively decomposed and solubilized. This is to remove it from the pulp fibers. Patent Document 1 discloses, as a method for treating pulp fibers with an ozone-containing aqueous solution, a method in which an ozone-containing aqueous solution is placed in a treatment tank and the separated pulp fibers are placed in the ozone-containing aqueous solution. In the above method, it is preferable to appropriately stir the ozone-containing aqueous solution to create a water flow during the treatment. It may be generated.

Japanese Unexamined Patent Publication No. 2016-881

Patent Document 1 describes that "recycled pulp fiber" is reused as ordinary "pulp fiber", but Patent Document 1 describes that it can be used as a pulp fiber for a medium as a medium for cellulase-producing bacteria. Not listed.

Pulp fibers are often used as absorbers and the like in sanitary products, and many of the pulp fibers are derived from coniferous trees. It is known that pulp fibers derived from softwoods contain about 10 to about 25% by mass of hemicellulose in addition to about 50 to about 60% by mass of cellulose. Hemicellulose is abundant in the cell wall of plants. When the pulp fiber is used as a raw material for cellulose, for example, hemicellulose present in the pulp fiber may inhibit the function as a medium for cellulase-producing bacteria, or may reduce the cellulase productivity of the cellulase-producing bacteria, for example. be.

In the field of sanitary products, pulp fibers are used as absorbers and the like, and hemicellulose contained in the pulp fibers does not easily inhibit the function (for example, absorbency) of (i) sanitary products, (ii). Hemicellulose is generally not removed from the pulp fibers from the viewpoint of imparting elasticity to the pulp fibers, (iii) contributing to the yield of the produced pulp fibers, and the like.
Therefore, it is an object of the present disclosure to provide a method for producing a pulp fiber for a medium as a medium for a cellulase-producing bacterium, which is excellent in cellulase productivity.

The present disclosures are a method for producing pulp fibers for a medium as a medium for cellulase-producing bacteria from pulp fibers to be treated, and are a treatment containing a treatment liquid containing a pulp fiber-containing substance containing the pulp fibers to be treated. The inclusion of a pulp fiber forming step for a medium, which forms the pulp fiber for a medium having a hemicellulose content of less than 8.0% by mass from the pulp fiber to be treated by supplying an ozone-containing gas to the tank. I found a way to characterize it.

The method for producing a pulp fiber for a medium as a medium for a cellulase-producing bacterium of the present disclosure is excellent in cellulase productivity.

It is a flowchart which shows the embodiment which concerns on the method of this disclosure. It is the schematic which shows the structural example of the apparatus of the ozone treatment process of FIG. It is the schematic which shows the other structural example of the apparatus of the ozone treatment process of FIG. It is the schematic which shows the other structural example of the apparatus of the ozone treatment process of FIG.

The present disclosure specifically relates to the following aspects.
[Aspect 1]
A method for producing a pulp fiber for a medium as a medium for a cellulase-producing bacterium from a pulp fiber to be treated.
By supplying an ozone-containing gas to a treatment tank containing a treatment liquid containing a pulp fiber-containing material containing pulp fibers to be treated, the pulp fibers to be treated have a hemicellulose content of less than 8.0% by mass. Pulp fiber formation step for medium, forming pulp fiber for medium,
The above method, which comprises.

In the above production method, pulp fibers for a medium having a hemicellulose content of less than 8.0% by mass can be produced from the pulp fibers to be treated. Therefore, the above-mentioned production method can produce pulp fibers for a medium having excellent cellulase productivity using cellulase-producing bacteria.

[Aspect 2]
The method according to aspect 1, wherein the pulp fiber for a medium has a lignin content of 0.10% by mass or less.

It is known that pulp fiber contains lignin in addition to cellulose. For example, it is known that softwoods, which are often used in hygiene products, contain 20 to 30% by mass of lignin.
Further, when the pulp fiber is used as a medium for cellulase-producing bacteria, when the lignin present in the pulp fiber inhibits the function as a medium for cellulase-producing bacteria, for example, the cellulase productivity of the cellulase-producing bacteria is reduced. In some cases.

In the above production method, pulp fibers for a medium having a lignin content of 0.10% by mass or less can be produced from pulp fibers contained in used sanitary products. Therefore, the above-mentioned production method can produce pulp fibers for a medium having excellent cellulase productivity using cellulase-producing bacteria.

[Aspect 3]
The method according to aspect 1 or 2, wherein the pulp fiber for a medium has an ash content of 0.65% by mass or less.
Ash tends to inhibit the saccharification of cellulose. Since the pulp fiber for the medium has a predetermined ash content, it is difficult for the ash to be mixed into the cellulase produced using the cellulase-producing bacterial medium containing the pulp fiber for the medium, and the saccharification of cellulose using the cellulase is inhibited. It's hard to do.

[Aspect 4]
The method according to any one of aspects 1 to 3, wherein bacteria are not detected in the pulp fibers for the medium by the pour culture method and / or the plate culture method.
In the above production method, bacteria are not detected in the pulp fibers for the medium by the pour culture method and / or the plate culture method. Therefore, when the pulp fibers for the medium are used as the medium for the cellulase-producing bacteria, the cellulase is produced by the cellulase-producing bacteria. Is less likely to be inhibited.

[Aspect 5]
In the pulp fiber forming step for a medium, the ozone-containing gas is brought into contact with the pulp fiber-containing material so that the CT value, which is the product of the ozone concentration and the treatment time, is 6,000 to 12,000 ppm · min. The method according to any one of aspects 1 to 4, wherein the pulp fibers for a medium are formed by allowing the pulp fibers to be formed.

In the above production method, in the pulp fiber formation step for a medium, ozone-containing gas is brought into contact with the pulp fiber-containing material under predetermined conditions to form pulp fibers for a medium. Therefore, in the above production method, pulp fibers for a medium having a predetermined lignin content can be easily produced from the pulp fibers.

[Aspect 6]
The above method is the next step,
The preparation step of preparing the treatment tank including the pulp fiber-containing material supply port, the treatment liquid discharge port, and the ozone-containing gas supply port arranged at a position below the treatment tank.
Pulp fiber-containing material supply step, which supplies the pulp fiber-containing material from the pulp fiber-containing material supply port to the processing tank.
An ozone-containing gas supply step in which the ozone-containing gas is supplied from the ozone-containing gas supply port to the treatment liquid in the treatment tank.
In the treatment tank, the pulp fiber-containing material is brought into contact with the ozone-containing gas while raising the ozone-containing gas to form the pulp fiber for the medium from the pulp fiber to be treated. Fiber formation step,
A treatment liquid discharge step in which the treatment liquid containing the pulp fibers for a medium is discharged from the treatment liquid discharge port,
The method according to any one of aspects 1 to 5, wherein the method comprises.

Since hemicellulose has a lower specific gravity than cellulose, pulp fibers having a relatively low hemicellulose content (pulp fibers having a relatively high cellulose content) have a relatively high hemicellulose content (cellulose content is high). It tends to have a relatively high specific gravity than (relatively low pulp fiber). On the other hand, in the solution, the ozone-containing gas rises while consuming ozone, so that the ozone-containing gas existing at the lower position has a higher ozone content than the ozone-containing gas existing at the upper position ( That is, it tends to be fresh).

The production method includes a predetermined preparation step, a pulp fiber content supply step, an ozone-containing gas supply step, a pulp fiber formation step for a medium, and a treatment liquid discharge step. In the pulp fiber forming step for a medium, the ozone-containing gas is raised to bring the pulp fiber-containing material into contact with the ozone-containing gas.

In the above production method, pulp fibers having a relatively low hemicellulose content (pulp fibers having a relatively high cellulose content) and pulp fibers having a relatively high hemicellulose content (pulp fibers having a relatively low cellulose content) ), And pulp fibers with a relatively low hemicellulose content (pulp fibers with a relatively high cellulose content) are likely to be discharged from the treatment liquid discharge port. In addition, the fresh ozone-containing gas comes into contact with pulp fibers having a relatively low hemicellulose content, and the hemicellulose contained therein is more easily decomposed. Therefore, the above-mentioned production method can produce pulp fibers for a medium having excellent cellulase productivity using cellulase-producing bacteria.

In general, the higher the lignin content, the lower the specific gravity of the pulp fiber. Therefore, in the above production method, the pulp fiber having a relatively low lignin content has a relatively low lignin content. Since the sedimentation property is relatively higher than that of the high pulp fiber, the fresher ozone-containing gas can come into contact with the pulp fiber having a relatively low lignin content and further decompose the lignin contained therein.

The ozone-containing gas supply port is located below the treatment tank, specifically, from the bottom of the treatment tank, preferably 30%, more preferably 20%, and even more preferably 10% of the height of the treatment tank. Means the range of%.
Further, the pulp fiber-containing material supply port may be arranged below the ozone-containing gas supply port, and may be arranged above the ozone-containing gas supply port, and the treatment liquid discharge port may be arranged above the ozone-containing gas supply port. It may be located below the mouth and above the mouth.

[Aspect 7]
The treatment liquid discharge port is arranged below the pulp fiber-containing material supply port.
In the pulp fiber forming step for a medium, the pulp fiber-containing material is brought into contact with the ozone-containing gas while the pulp fiber-containing material is lowered.
The method according to aspect 6.

In the above production method, since the falling pulp fiber-containing material is brought into contact with the rising ozone-containing gas, the frequency of contact of the pulp fiber-containing material with the ozone-containing gas increases, and the pulp fiber contained in the treatment liquid (pulp after ozone treatment). The distribution of the hemicellulose content of the fiber) becomes narrower (less variation). Further, since the fresh ozone-containing gas can come into contact with the pulp fibers having a relatively low hemicellulose content, the hemicellulose content of the pulp fibers (pulp fibers after ozone treatment) contained in the treatment liquid tends to be low. Further, since the treatment liquid discharge port is arranged below the pulp fiber-containing material supply port, pulp fibers having a relatively low hemicellulose content (cellulose content is relative) from the treatment liquid discharge port. High pulp fiber) is easily discharged.

The manufacturing method according to the seventh aspect includes both so-called continuous manufacturing methods and batch manufacturing methods. Further, "lowering the pulp fiber-containing material" means that at least a part of the pulp fiber-containing material is lowered, for example, when the entire treatment liquid in the treatment tank is lowered. The whole includes a falling portion of the pulp fiber-containing material when the treatment liquid in the treatment tank is convected up and down.

[Aspect 8]
The treatment liquid discharge port is arranged above the pulp fiber-containing material supply port.
In the pulp fiber forming step for a medium, the pulp fiber-containing material is brought into contact with the ozone-containing gas while raising the pulp fiber-containing material.
The method according to aspect 6.

In the above production method, the rising pulp fiber-containing material is brought into contact with the rising ozone-containing gas, so that the pulp fiber-containing material is in contact with the ozone-containing gas for a long time, and the hemicellulose content in the pulp fiber is lowered. It will be easier.

The manufacturing method according to the eighth aspect includes both so-called continuous manufacturing methods and batch manufacturing methods. Further, "increasing the pulp fiber content" means that at least a part of the pulp fiber content is increased, for example, when the entire treatment liquid in the treatment tank is increased. The whole includes a portion where the pulp fiber-containing material is rising when the treatment liquid in the treatment tank is convected up and down.

[Aspect 9]
In the pulp fiber-containing material supply step, the pulp fiber-containing material is continuously supplied from the pulp fiber-containing material supply port to the treatment tank at a first flow rate, and in the treatment liquid discharge step, the treatment liquid is supplied. The method according to any one of aspects 6 to 8, wherein the treatment liquid is continuously discharged from the treatment liquid discharge port at a second flow rate.

In the above production method, the pulp fiber-containing material is continuously supplied from the pulp fiber-containing material supply port to the treatment tank at the first flow rate in the pulp fiber-containing material supply step, and the treatment liquid is continuously supplied in the treatment liquid discharge step. Since the pulp fiber-containing material to be treated is continuously discharged from the treatment liquid discharge port at a second flow rate, the treatment time of the pulp fiber-containing material to be treated is made uniform, and the distribution of the hemicellulose content of the pulp fiber for medium contained in the treatment liquid is narrowed. (There is less variation). Therefore, the above-mentioned production method can produce pulp fibers for a medium having excellent cellulase productivity using cellulase-producing bacteria.

[Aspect 10]
The pulp fiber-containing material contains the pulp fiber to be treated derived from used sanitary products and a super absorbent polymer.
In the pulp fiber forming step for a medium, at least a part of the superabsorbent polymer is dissolved in the treatment liquid.
The method according to any one of aspects 6 to 9.

In used sanitary goods, in an absorber containing pulp fibers and a superabsorbent polymer, (i) the superabsorbent polymer enlarges as it absorbs a liquid such as a body fluid and entrains the pulp fibers, (ii) enlargement. In many cases, the plurality of superabsorbent polymers and the plurality of pulp fibers form a connecting structure due to the superabsorbent polymers that have become entangled with each other and cause gel blocking while entraining the pulp fibers.

In the above production method, in the pulp fiber forming step for a medium, the pulp fiber-containing material and the ozone-containing gas are brought into contact with each other while raising the ozone-containing gas. In free superabsorbent polymers and free pulp fibers, and linked structures, free superabsorbent polymers and linked structures with relatively low buoyancy settle more than free pulp fibers with relatively high buoyancy. Tends to be high. On the other hand, since the ozone-containing gas consumes ozone and rises while processing the pulp fiber-containing material, the ozone-containing gas existing at the lower position is more ozone than the ozone-containing gas existing at the upper position. The content tends to be high (ie, fresh).

Therefore, in the above production method, the free superabsorbent polymer having a relatively high sedimentation property and the superabsorbent polymer in the linked structure are accurately oxidatively decomposed with a fresher ozone-containing gas to form the linked structure. Ozone-containing gas takes time to release the constituent pulp fibers, which have relatively low sedimentation properties and take a relatively long time to reach the treatment liquid discharge port. The hemicellulose contained in the free pulp fibers can be decomposed.

Further, as described above, pulp fibers having a relatively low hemicellulose content (pulp fibers having a relatively high cellulose content) are pulp fibers having a relatively high hemicellulose content (pulp having a relatively low cellulose content). In the above production method, the fresher ozone-containing gas comes into contact with pulp fibers having a relatively low hemicellulose content, and the hemicellulose contained therein can be further decomposed.
Therefore, the above-mentioned production method can produce pulp fibers for a medium having excellent cellulase productivity using cellulase-producing bacteria.

[Aspect 11]
The method according to aspect 10, wherein the treatment liquid is acidic, weakly acidic or neutral.
In the above production method, the treatment liquid is acidic (specifically, pH 0.0 or more and less than pH 3.0, preferably pH 2.5 or more and less than pH 3.0) and weakly acidic (specifically, pH 3.0 or more). And pH 6.0 or less) or neutral (specifically, pH 6.0 or more and pH 8.0 or less, preferably pH 6.0 or more and pH 7.0 or less). Therefore, if the superabsorbent polymer to be treated can be inactivated by acid, or if the superabsorbent polymer to be treated has already been inactivated, the superabsorbent polymer is subsequently inactivated. The state can be maintained. As a result, even when the highly water-absorbent polymer and the pulp fiber form a linked structure, ozone in the ozone-containing gas can remove the highly water-absorbent polymer constituting the linked structure. At the same time, ozone in the ozone-containing gas acts on the pulp fibers constituting the connecting structure, and the hemicellulose content of the pulp fibers can be reduced.
Therefore, the above-mentioned production method can produce pulp fibers for a medium having excellent cellulase productivity using cellulase-producing bacteria.

[Aspect 12]
The method according to aspect 10 or 11, further comprising an inactivation step of inactivating the superabsorbent polymer with an acid prior to the pulp fiber-containing material supply step.

Since the above-mentioned production method further includes a predetermined inactivation step, ozone in the ozone-containing gas is used even when the highly water-absorbent polymer and the pulp fiber form a connecting structure. Immediately after the highly water-absorbent polymer derived from sanitary goods and the pulp fiber-containing material containing the pulp fiber are supplied to the treatment tank, the highly water-absorbent polymer constituting the connecting structure can be removed, and the high water-absorbent polymer constituting the connecting structure can be removed, and the pulp fiber-containing material in the ozone-containing gas can be removed. Ozone acts on the pulp fibers that make up the linked structure and can reduce the hemicellulose content of the pulp fibers.
Therefore, the above-mentioned production method can produce pulp fibers for a medium having excellent cellulase productivity using cellulase-producing bacteria.

[Aspect 13]
The method according to aspect 12, wherein the acid is an acid capable of forming a complex with a metal ion contained in excrement.

In the above production method, since the acid is an acid capable of forming a complex with the metal ions contained in the excrement, the produced pulp fibers for the medium are less likely to contain the metal ions. Therefore, in the step of using the pulp fiber for the medium from the pulp fiber for the medium, the metal ions and their precipitates are less likely to damage the equipment used in the step of using the pulp fiber for the medium.

[Aspect 14]
The method according to any one of aspects 1 to 13, further comprising a cellulase production step of producing cellulase using the pulp fiber for a medium after the pulp fiber formation step for a medium.
In the above production method, cellulase can be efficiently produced using pulp fibers for a medium.

[Aspect 15]
Pulp fiber for medium as a medium for cellulase-producing bacteria derived from used sanitary products containing pulp fiber.
The pulp fiber for a medium has a hemicellulose content of less than 8.0% by mass.
The pulp fiber for a medium, which is characterized by the above.

Since the pulp fiber for a medium has a predetermined hemicellulose content, the productivity of cellulase using a cellulase-producing bacterium is excellent.

[Aspect 16]
The pulp fiber for a medium according to aspect 15, wherein the pulp fiber for a medium has a lignin content of 0.10% by mass or less.
Since the pulp fiber for a medium has a predetermined lignin content, the productivity of cellulase using a cellulase-producing bacterium is excellent.

[Aspect 17]
The pulp fiber for a medium according to aspect 15 or 16, wherein the pulp fiber for a medium has an ash content of 0.65% by mass or less.
Since the pulp fiber for the medium has a predetermined ash content, it is difficult for the ash to be mixed into the cellulase produced using the cellulase-producing bacterial medium containing the pulp fiber for the medium, and the saccharification of cellulose using the cellulase is inhibited. It's hard to do.

[Aspect 18]
The pulp fiber for a medium according to any one of aspects 15 to 17, wherein bacteria are not detected in the pulp fiber for a medium by a pour culture method and / or a plate culture method.

Bacteria are not detected in the pulp fibers for the medium by the pour culture method and / or the plate culture method, so that the production of cellulase by the cellulase-producing bacteria is less likely to be inhibited when the pulp fibers for the medium are used as the medium for the cellulase-producing bacteria. ..

[Aspect 19]
The use of pulp fibers for a medium as a medium for cellulase-producing bacteria for the production of cellulase.
The pulp fiber for the medium is derived from a used sanitary product containing the pulp fiber.
The pulp fiber for a medium has a hemicellulose content of less than 8.0% by mass.
The above use, characterized by that.

In the above use, since the pulp fiber for the medium has a predetermined hemicellulose content, the productivity of cellulase using a cellulase-producing bacterium is excellent.

[Aspect 10]
The use according to aspect 19, wherein the pulp fiber for a medium has a lignin content of 0.10% by mass or less.
In the above use, since the pulp fiber for the medium has a predetermined lignin content, the productivity of cellulase using a cellulase-producing bacterium is excellent.

Hereinafter, a method for producing a pulp fiber for a medium from a pulp fiber to be treated (hereinafter, may be simply referred to as a “method for producing a pulp fiber for a medium”) will be described.
The pulp fiber to be treated is not particularly limited as long as it is a pulp fiber, for example, unused pulp fiber (for example, virgin pulp fiber), used pulp fiber (for example, pulp derived from used sanitary products). Fiber) and the like.

The above-mentioned used hygiene products are hygiene products used by the user, which are in a state where the user's liquid excrement is absorbed, and hygiene products which are used but do not absorb excrement. Includes unused and discarded hygiene products.

In the present specification, the term "to be treated" in the pulp fiber to be treated is a modifier for distinguishing between the pulp fiber before treatment and the pulp fiber for a culture medium after treatment, and other than that. It has no intention.
Further, in the present specification, as "pulp fiber to be treated", an embodiment of used pulp fiber, particularly pulp fiber derived from used sanitary goods, is mentioned, in which "pulp to be treated" is mentioned. "Fiber" may be simply referred to as "pulp fiber".

First, a configuration example of hygiene products will be described. The hygiene product includes, for example, a liquid permeable sheet, a liquid permeable sheet, and an absorber arranged between the liquid permeable sheet and the liquid permeable sheet. Examples of hygienic products include disposable diapers, urine absorbing pads, sanitary napkins, bed sheets, pet sheets and the like.

Examples of the constituent members of the liquid permeable sheet include non-woven fabrics or films, and specific examples thereof include liquid permeable non-woven fabrics, synthetic resin films having liquid permeable holes, and composite sheets thereof. Examples of the constituent members of the liquid-impermeable sheet include non-woven fabrics or films, and specific examples thereof include liquid-impermeable non-woven fabrics, liquid-impermeable synthetic resin films, and composite sheets thereof.

Examples of the constituent members of the absorber include an absorbent core (for example, pulp fiber and a super absorbent polymer) and a core wrap. The pulp fiber is not particularly limited as long as it can be used as a sanitary product, and examples thereof include cellulosic fibers. Examples of the cellulosic fiber include wood pulp (for example, softwood pulp, hardwood pulp), crosslinked pulp, non-wood pulp and the like. The super absorbent polymer (SAP) is not particularly limited as long as it can be used as a sanitary product, and examples thereof include polyacrylate-based, polysulfonate-based, and maleic anhydride-based polymers. Be done.

One surface and the other surface of the absorber are bonded to a liquid-permeable sheet and a liquid-impermeable sheet, respectively, via an adhesive. In a plan view, the portion of the liquid permeable sheet that extends outside the absorber (peripheral portion) so as to surround the absorber so as to surround the absorber of the liquid permeable sheet. It is joined to the outwardly extending portion (peripheral portion) of the absorber via an adhesive. Therefore, the absorber is wrapped inside the joint of the liquid permeable sheet and the liquid permeable sheet. The adhesive is not particularly limited as long as it can be used as a sanitary product and the bonding strength is reduced by softening or the like due to hot water described later, and examples thereof include a hot melt type adhesive. Examples of the hot melt type adhesive include rubber-based adhesives such as styrene-ethylene-butadiene-styrene, styrene-butadiene-styrene, and styrene-isoprene-styrene, or olefin-based pressure-sensitive adhesives such as polyethylene, or heat-sensitive adhesives. Adhesives can be mentioned.

FIG. 1 is a flowchart showing a material separation method for separating used hygiene products into constituent materials. This material separation method is a method of separating used hygiene products into a film, a non-woven fabric, a pulp fiber, and a super absorbent polymer. This material separation method includes a pretreatment step S11, a decomposition step S12, and a separation step S13.
In the pretreatment step S11, the used hygiene product is swollen with water. In the decomposition step S12, a physical impact is applied to the swollen used hygiene product, and the used hygiene product is combined with a film, a non-woven fabric, a core wrap, etc. and an absorbent core (for example, pulp fiber and super absorbent polymer). Disassemble into. In the separation step S13, the film, the non-woven fabric, the pulp fibers, and the super absorbent polymer are separated.

The method for producing pulp fiber for a medium of the present disclosure is included in the separation step S13 of this material separation method. When a mixture of pulp fibers and a highly water-absorbent polymer (pulp fiber-containing material) is obtained in advance by some method, production of pulp fibers for a medium in the pretreatment step S11, the decomposition step S12, and the separation step S13. No steps prior to the method are required. Hereinafter, each step will be described.

The pretreatment step S11 is in the state when a plurality of used hygiene products are collected from the outside, that is, in a rolled state or a folded state without being broken or cut. As it is, it absorbs water and swells without inactivating the super absorbent polymer of the absorber. In the present embodiment, the used sanitary goods are made to absorb hot water and swell, or the absorbed water is heated after absorbing and swelling the water to make hot water. Hot water refers to water having a temperature higher than normal temperature (20 ° C ± 15 ° C (5-35 ° C): JIS Z 8703).

Normally, the amount of liquid excrement actually absorbed by a used hygiene product is very small compared to the maximum absorption amount that the hygiene product can absorb (for example, about 10 to 20% by mass of the maximum absorption amount). ). In the present embodiment, in the pretreatment step S11, by immersing the used sanitary goods in warm water, water reaches an amount close to the maximum absorption amount of the used sanitary goods (for example, 80% by mass or more of the maximum absorption amount). To absorb. Alternatively, the used hygiene product is immersed in water at room temperature to absorb water to an amount close to the maximum absorption amount of the used hygiene product, and then the entire used hygiene product is heated to the temperature of warm water. Thereby, the used sanitary goods can be made into a very inflated state with hot water or normal temperature water (hereinafter, also simply referred to as "warm water"). As a result, used hygiene products are subject to very high internal pressure. The purpose of making the water hot is mainly to weaken the adhesive force of the adhesive as described later.

Here, used hygiene products are initially immersed in warm water when they are rolled or folded with the liquid permeable sheet on the outside (the liquid permeable sheet is hidden inside). As a result, the absorber of used sanitary goods absorbs hot water in warm water and expands. As a result, the internal pressure of the used hygiene product increases, and the force that tries to open the used hygiene product outward is exerted, so that the used hygiene product in the rolled or folded state is moved outward. It opens toward you and becomes almost flat. That is, the used hygiene products can be flattened in warm water. At this time, since the absorber absorbs a large amount of hot water and expands very much in the used sanitary goods, the surface of the used sanitary goods, that is, the liquid-permeable sheet and the liquid-impermeable sheet surrounding the absorber. One of the parts is in a state where it is likely to be easily torn off. That is, in the pretreatment step S11, the used hygiene product can be put into a state where one of the surfaces is likely to be torn and cut. If the used hygiene product is in a flatly unfolded state from the beginning, any part of the surface is likely to be easily torn off in that state. This condition cannot occur when the used sanitary goods are broken or the like.

Furthermore, the used sanitary goods are soaked in hot water and / or absorb the hot water to soften the adhesive (for example, hot melt adhesive) used for joining between the constituent members by the heat of the hot water. It is possible to reduce the bonding force of the adhesive. For example, the adhesive that joins the peripheral portion of the liquid permeable sheet and the peripheral portion of the liquid impermeable sheet can be softened by the heat of warm water to reduce the bonding force of the adhesive. Further, the adhesive for joining the liquid-permeable sheet and the absorber and the adhesive for joining the liquid-impermeable sheet and the absorber can be softened by the heat of warm water to reduce the bonding force of the adhesives.

As described above, in the pretreatment step S11, due to the expansion of the absorber of the used hygiene product, any part of the surface of the used hygiene product is likely to be torn off, and the adhesive strength is reduced. A state, can occur. When the used hygiene product is in such a state, the used hygiene product can be reliably disassembled in the disassembly step described later.

The temperature of the hot water in the pretreatment step S11 is not particularly limited as long as the adhesive of the used sanitary goods can be softened, but for example, 60 ° C. or higher is mentioned, and preferably 70 ° C. or higher and 98 ° C. or lower. By setting the temperature of the hot water to 70 ° C. or higher, the adhesive for joining the constituent members can be further softened by the heat of the hot water, and the bonding force of the adhesive can be further reduced. By setting the temperature of the hot water to 98 ° C. or lower, the hot water surely exists as a liquid, so that the used sanitary goods can more reliably absorb the hot water. Due to the expansion of the absorber and the heat of the hot water, it is possible to more reliably generate a state in which the surface of the used sanitary product is likely to be torn off and a state in which the bonding force of the adhesive is reduced. For temperature measurement, measure the temperature of hot water in which used sanitary goods are immersed, or measure the temperature 5 mm inside the surface of used sanitary goods that have absorbed water to an amount close to the maximum absorption amount ( Insert the tip of the temperature sensor).

In addition, sterilization of constituent materials is extremely important in the reuse of used hygiene products. By setting the temperature of the hot water to 70 ° C. or higher, it is possible to exert the effect of sterilizing (disinfecting) used sanitary goods, which is preferable.

The treatment time in the pretreatment step S11, that is, the time for immersing the used hygiene product in warm water is not particularly limited as long as the absorber of the used hygiene product can expand, but is, for example, 2 to 60 minutes. It is preferably 4 to 30 minutes. If the time is too short, the absorber cannot expand sufficiently, and if it is too long, the time is wasted and the processing cost increases unnecessarily.

The amount of hot water absorbed by the absorber in the pretreatment step S11 is not particularly limited as long as the absorber can expand to the extent that the used sanitary products can be decomposed in the decomposition step described later. 80% by mass or more of the maximum absorption amount of the above, preferably 90% by mass or more. As a result, the used hygiene product can be fully inflated with water. As a result, an extremely high internal pressure can be generated in the absorber of the used hygiene product.

However, the maximum absorption amount is measured by the following procedure.
(1) Unused hygiene products are dried in an atmosphere of 100 ° C. or higher, and the mass of the hygiene products is measured.
(2) When a stretchable material (for example, a stretchable member around the legs, around the waist, etc.) that can form a pocket that makes it difficult for water to reach the absorber is placed in the hygiene product, a cut is made in the stretchable member. Flatten the hygiene products by putting in.
(3) Immerse sanitary goods in a water bath filled with sufficient tap water with the liquid permeable sheet facing down, and leave it for 30 minutes.
(4) After leaving, the sanitary product is placed on a net with the liquid permeable sheet facing down, drained for 20 minutes, and then the mass of the sanitary product is measured.
Then, the mass difference before and after immersion in tap water is defined as the maximum absorption amount.

Next, in the disassembling step S12, a physical impact is applied to the plurality of used hygiene products developed and swollen by the pretreatment step S11, and the plurality of used hygiene products are formed into a film (liquid impermeable sheet). It decomposes into a non-woven fabric (liquid permeable sheet) and core wrap, and an absorbent core (for example, an absorber and a super absorbent polymer).

The used hygiene product is unfolded and flat by the pretreatment step S11, and any part of the surface is likely to be torn off due to expansion. The bonding strength of the is reduced. Therefore, in the disassembly step S12, the liquid permeable sheet (nonwoven fabric) and the liquid whose bonding strength is particularly reduced in any part of the surface by applying a physical impact to the used sanitary goods in that state. The joint with the impermeable sheet (film) is torn off. Thereby, the joint portion can be torn (peeled). The physical impact is not particularly limited, but for example, a method of hitting the used hygiene product on a surface made of a material harder than the used hygiene product, and the used hygiene product are arranged face-to-face with each other. Examples thereof include a method of pressing from both sides while sandwiching the roll between a pair of rolls and passing the roll.

In the present embodiment, the disassembling step S12 includes a step of charging a plurality of swollen used sanitary goods into the bottom of a rotating drum having a horizontal rotating shaft, and rotating the rotating drum around the rotating shaft. It includes the process of pulling a plurality of used sanitary goods to the top of the rotating drum and hitting them against the bottom. Thereby, a physical impact can be applied to a plurality of used hygiene products in a stable, continuous (continuous) and easy manner. Examples of the rotating drum include a rotating drum in the washing tub of a horizontal washing machine, so that the disassembly step S12 can be carried out using an existing horizontal washing machine (for example, ECO-22B manufactured by Inamoto Manufacturing Co., Ltd.). The size of the rotating drum is not particularly limited as long as the above impact can be realized, but the inner diameter and depth are, for example, 50 to 150 cm and 30 to 120 cm. The rotation speed of the rotating drum is not particularly limited as long as the above impact can be realized, and examples thereof include 30 times / minute to 100 times / minute.

In addition, the temperature of the used sanitary goods is kept relatively high by the hot water absorbed in the used sanitary goods, but from the viewpoint of suppressing the temperature drop of the adhesive and maintaining the sterilizing effect, The temperature of the atmosphere in the rotating drum is preferably 70 ° C. or higher, more preferably 75 ° C. or higher. The temperature inside the rotating drum is preferably 98 ° C. or lower, more preferably 90 ° C. or lower, from the viewpoint of handling used sanitary goods. It is preferable that the amount of water in the rotating drum is as small as possible, and that the amount of used sanitary goods at least at the bottom is so small that it does not fall below the water surface. When the used hygiene product is below the water surface, the impact on the used hygiene product is absorbed by the water, and it becomes difficult to give the desired impact to the used hygiene product. The time for rotating the rotating drum is not particularly limited as long as the liquid permeable sheet, the liquid permeable sheet, the core wrap, and the like can be decomposed, but is preferably 2 to 40 minutes, for example. Is 4 to 20 minutes.

In used hygiene products, the joint between the liquid-permeable sheet (nonwoven fabric) and the liquid-impermeable sheet (film) is torn and torn by a physical impact. At the same time, through the crevice, the internal pressure of the absorber causes the absorbent cores (eg, pulp fibers and superabsorbent polymer) in the used hygiene product to spurt out (jump out). As a result, used sanitary products can be replaced with liquid-permeable sheets (nonwoven fabrics), liquid-impermeable sheets (films), core wraps, and absorbent cores (for example, pulp fiber-containing materials containing pulp fibers and superabsorbent polymers). In addition, it can be disassembled more reliably.

Next, in the separation step S13, the plurality of films (liquid permeable sheet), the plurality of non-woven fabrics (liquid permeable sheet), the core wrap, and the like are separated from the absorbent core (for example, pulp fiber and super absorbent polymer). However, the non-woven fabric may remain bonded to the film. The separation method is not particularly limited, and examples thereof include a method using a sieve that allows an absorption core to pass through without passing through a liquid-permeable sheet, a liquid-impermeable sheet, a core wrap, or the like.

In the present embodiment, the separation step S13 includes an inactivation step S31 that inactivates the superabsorbent polymer with an aqueous solution containing an inactivating agent before separating the film, the non-woven fabric, the core wrap, and the absorption core, and the film. And the non-woven fabric may include a first separation step S32 that separates the non-woven fabric from the pulp fiber, the inactivated superabsorbent polymer and the mixture containing the sewage discharged from the superabsorbent polymer by inactivation.

In the inactivation step S31, before the first separation step S32, a liquid permeable sheet (nonwoven fabric), a liquid permeable sheet (film) and an absorber (pulp fiber and superabsorbent polymer) are subjected to a superabsorbent polymer. Is immersed in an aqueous solution containing an inactivating agent that can be inactivated. Thereby, the super absorbent polymer adhering to the liquid permeable sheet, the liquid permeable sheet and the pulp fiber can be inactivated. Thereby, the superabsorbent polymer in a high viscosity state before inactivation can be made into a superabsorbent polymer in a low viscosity state by dehydration by inactivation.

Here, the inactivating agent is not particularly limited, and examples thereof include acids (for example, inorganic acids and organic acids), lime, calcium chloride, magnesium sulfate, magnesium chloride, aluminum sulfate, aluminum chloride and the like. The acid is preferable because it does not leave ash in the pulp fibers. When an acid is used as the inactivating agent, the pH is preferably 2.5 or less, and more preferably 1.3-2.4. If the pH is too high, the water absorption capacity of the super absorbent polymer cannot be sufficiently reduced. In addition, the bactericidal ability may be reduced. If the pH is too low, there is a risk of equipment corrosion, and a large amount of alkaline chemicals are required for neutralization treatment during wastewater treatment.

Examples of the inorganic acid include sulfuric acid, hydrochloric acid, and nitric acid, but sulfuric acid is preferable from the viewpoint of not containing chlorine and cost. On the other hand, examples of the organic acid include citric acid, tartaric acid, glycolic acid, malic acid, succinic acid, acetic acid, ascorbic acid and the like, and an acid capable of forming a complex with a metal ion contained in excrement, for example, citric acid. Hydroxycarbonate-based organic acids such as acids, tartaric acid, and gluconic acid are particularly preferred. Examples of the metal ion contained in the excrement include calcium ion. This is because the metal ions in the excrement can be trapped and removed by the chelating effect of the acid capable of forming a complex with the metal ions contained in the excrement. In addition, citric acid can be expected to have a high effect of removing stain components due to its cleaning effect.
Since the pH changes depending on the water temperature, the pH in the present disclosure refers to the pH measured at an aqueous solution temperature of 20 ° C.

The treatment temperature of the inactivating step S31, that is, the temperature of the aqueous solution containing the inactivating agent is not particularly limited as long as the inactivating reaction proceeds. The treatment temperature may be room temperature or higher than room temperature, and examples thereof include 15 to 30 ° C. Further, the treatment time of the inactivating step S31, that is, the time for immersing the liquid-permeable sheet, the liquid-impermeable sheet and the absorber in the aqueous solution containing the inactivating agent is as long as the superabsorbent polymer is inactivated and dehydrated. Although not particularly limited, for example, 2 to 60 minutes can be mentioned, preferably 5 to 30 minutes. Further, the amount of the aqueous solution in the inactivating step S31, that is, the amount of the aqueous solution containing the inactivating agent is not particularly limited as long as the inactivating reaction proceeds. The amount of the aqueous solution is, for example, preferably 300 to 3000 parts by mass, more preferably 500 to 2500 parts by mass, and further preferably 1000 to 2000 parts by mass with respect to 100 parts by mass of used sanitary goods.

In the first separation step S32, the liquid permeable sheet (nonwoven fabric), the liquid permeable sheet (film) and the core wrap are discharged from the pulp fiber, the inactivated superabsorbent polymer and the superabsorbent polymer by inactivation. Separate from the mixture containing sewage. However, the sewage is sewage containing water released from the superabsorbent polymer by dehydration with an aqueous solution containing an inactivating agent in the inactivating step S31, that is, liquid derived from excrement and water derived from warm water.

In the first separation step S32, the method for separating the liquid permeable sheet and the liquid impermeable sheet from the pulp fiber, the super absorbent polymer and the sewage (pulp fiber-containing substance) is not particularly limited. For example, a product (liquid permeable sheet, liquid permeable sheet, pulp fiber, super absorbent polymer, sewage, etc.) produced by the inactivation step is used as a screen having an opening of 5 to 100 mm, preferably an opening of 10 to 60 mm. Discharge while passing through. Thereby, the pulp fibers, the superabsorbent polymer and the sewage remain in the wastewater, and the liquid-permeable sheet and the liquid-impermeable sheet remain on the screen, so that their products can be separated. In addition, other large-shaped objects such as non-woven fabrics and films may remain on the screen. In particular, since the superabsorbent polymer is in a highly viscous state before inactivation, it is easy to separate the superabsorbent polymer attached to the liquid-permeable sheet, the liquid-impermeable sheet and the pulp fiber. I can't say. However, after inactivation, the superabsorbent polymer becomes low in viscosity due to dehydration. Therefore, the superabsorbent polymer adhered to the liquid-permeable sheet, the liquid-impermeable sheet and the pulp fiber is used as the liquid-permeable sheet. , Can be easily separated from liquid impermeable sheets and pulp fibers. Therefore, the constituent members of hygiene products can be efficiently separated and collected.

In the present embodiment, the separation step S13 may further include a second separation step S33 in which the adhesive at the joint portion is removed with a solvent that dissolves the adhesive at the joint portion between the film and the other member. In the present embodiment, the adhesive at each joint is removed with a solvent that dissolves the adhesive at each joint between the film, the non-woven fabric, and the absorber.

In the second separation step S33, the film (liquid permeable sheet) is joined to other members (nonwoven fabric of the liquid permeable sheet, liquid permeable sheet, absorber remaining on the surface of the liquid permeable sheet, etc.). Remove the adhesive on the part with a solvent. As a result, the film and other members can be separated from each other while maintaining the same shape without breaking or the like. Therefore, constituent members such as films for hygiene products can be efficiently recovered. Further, since the film and other members can be separated without leaving an adhesive on the film, the film can be reused as a high-purity resin. As a result, it is possible to prevent the adhesive from adversely affecting the film when it is reused. The same applies to the non-woven fabric as well as the film.

The solvent used in the second separation step S33 is not particularly limited as long as it can dissolve the adhesive, and for example, a terpene containing at least one of a terpene hydrocarbon, a terpene aldehyde, and a terpene ketone can be used. Can be mentioned. In this step, an aqueous solution containing terpenes is used, and the concentration of terpenes in the aqueous solution is, for example, 0.05% by mass or more and 2% by mass or less. It is preferably 0.075 to 1% by mass. If the concentration of terpenes is too low, the adhesive at the joint may not be able to dissolve. If the concentration of terpenes is too high, the cost can be high. In addition, the terpene not only dissolves an adhesive such as a hot melt adhesive, but also has an oil stain cleaning effect. Therefore, for example, when a component of a sanitary product such as a liquid-impermeable sheet has printing, the terpene can also decompose and remove the printing ink.

Examples of terpene hydrocarbons include myrcene, limonene, pinene, camphor, sapinen, phellandrene, parasimene, ocimene, terpinene, kalen, gingiberen, cariophyllene, bisabolen and sedren. Of these, limonene, pinene, terpinene, and karen are preferable. Examples of the terpene aldehyde include citronellal, citral, cyclocitral, safranal, ferlandral, perillaldehyde, geranial, and neral. Examples of the terpene ketone include camphor and tsuyoshi. Among the terpenes, terpene hydrocarbons are preferable, and limonene is particularly preferable. There are three types of limonene, d-limonene, l-limonene, and dipentene (dl-limonene), and any of them can be preferably used. One type of terpene can be used alone, or two or more types can be used in combination.

The treatment temperature of the second separation step S33, that is, the temperature of the aqueous solution containing the solvent is not particularly limited as long as the adhesive is dissolved and the used sanitary goods are decomposed into constituent members. The treatment temperature may be room temperature or higher than room temperature, and examples thereof include 15 to 30 ° C. Further, during the processing time of the second separation step S33, that is, the time for immersing the liquid-permeable sheet, the liquid-impermeable sheet and the absorber in the aqueous solution containing the solvent, the adhesive dissolves and the used sanitary goods are used. As long as it is disassembled into constituent members, it is not particularly limited. The processing time is, for example, 2 to 60 minutes, preferably 5 to 30 minutes. The amount of the aqueous solution in the second separation step S33, that is, the amount of the aqueous solution containing the solvent is not particularly limited as long as the adhesive is dissolved and the used sanitary goods are decomposed into constituent members. The amount of the aqueous solution is, for example, preferably 300 to 3000 parts by mass, and more preferably 500 to 2500 parts by mass with respect to 100 parts by mass of used hygiene products. By the second separation step S33, the amount of the adhesive remaining on the film, the non-woven fabric, the absorber and the like can be reduced to 1% by mass or less with respect to the film, the non-woven fabric, the absorber and the like.

In the present embodiment, as another preferable embodiment, the second separation step S33 may be performed together with the inactivation step S31. That is, while inactivating the superabsorbent polymer attached to the liquid-permeable sheet, the liquid-impermeable sheet and the pulp fiber, the liquid-permeable sheet, the liquid-impermeable sheet and the adhesive attached to the pulp fiber are dissolved. May be good. In this case, as the aqueous solution for immersing the liquid-permeable sheet, the liquid-impermeable sheet, the pulp fiber and the superabsorbent polymer, an aqueous solution containing both an inactivating agent and a solvent is used. As a result, in the inactivation step S31, the liquid-impermeable sheet (film), the liquid-permeable sheet (nonwoven fabric), and the absorber (pulp fiber and superabsorbent polymer) are substantially separated in the aqueous solution. can. Then, in the subsequent first separation step, the liquid-impermeable sheet (film) and the liquid-permeable sheet (nonwoven fabric) can be separated from the absorber (pulp fiber and superabsorbent polymer), and the second separation step. S33 can be omitted. In this case, the liquid-impermeable sheet (film) and the liquid-permeable sheet (nonwoven fabric) are substantially separated by removing the adhesive.

In the present embodiment, the separation step S13 further includes a first drying step S34 in which the film is dried in an atmosphere or hot air having a temperature higher than room temperature to remove the solvent after the step of removing the adhesive at the joint portion. It may be included. In the present embodiment, the non-woven fabric is also dried in this step.

Sterilization is extremely important in the reuse of used hygiene products. In the first drying step S34, a step of drying the separated film (liquid permeable sheet) and non-woven fabric (liquid permeable sheet) in a high temperature atmosphere or hot air is performed. The drying temperature is, for example, 105 to 210 ° C, preferably 110 to 190 ° C. The drying time depends on the drying temperature, but is, for example, 10 to 120 minutes, preferably 15 to 100 minutes. Thereby, not only the solvent remaining on the surface of the film and the non-woven fabric can be evaporated and removed, but also the film and the non-woven fabric can be sterilized by a high temperature atmosphere or hot air. As a result, it is possible to exert the effect of sterilization (disinfection) while removing the solvent.

On the other hand, in the present embodiment, the separation step S13 may include a third separation step S35 that separates the pulp fibers from the separated mixture. In the third separation step S35, the method for separating the pulp fibers from the separated mixture (including the pulp fibers, the super absorbent polymer and the sewage) is not particularly limited, but for example, the separated mixture is opened at 0. . Discharge while passing through a screen having a size of 1 to 4 mm, preferably a mesh size of 0.15 to 2 mm. Thereby, the superabsorbent polymer and sewage remain in the wastewater, and the pulp fiber (mainly the superabsorbent polymer remaining on the surface) remains on the screen, so that the pulp fiber can be separated from the mixture. Although this pulp fiber contains a lot of impurities, it can be reused in this state depending on the application.
A highly water-absorbent polymer is attached to the separated pulp fibers, and the separated pulp fibers and the highly water-absorbent polymer attached to the pulp fibers are mixed with water in a predetermined ratio. As a pulp fiber-containing material, the process proceeds to the ozone treatment step S36.

In the present embodiment, in the separation step S13, the highly water-absorbent polymer and pulp fibers, their connecting structures, and the pulp fiber-containing material containing water are treated with an aqueous solution containing ozone, and the pulp fibers adhere to the high. It includes an ozone treatment step S36 that reduces the molecular weight of the water-absorbent polymer, solubilizes it, and removes it.

In used sanitary goods, in an absorber containing pulp fibers and a superabsorbent polymer, (i) the superabsorbent polymer enlarges as it absorbs a liquid such as a body fluid and entrains the pulp fibers, (ii) enlargement. In many cases, the plurality of superabsorbent polymers and the plurality of pulp fibers form a connecting structure due to the superabsorbent polymers that have become entangled with each other and cause gel blocking while entraining the pulp fibers. The pulp fiber-containing material includes, in addition to the free pulp fiber and the free superabsorbent polymer, a linked structure composed of a plurality of superabsorbent polymers and a plurality of pulp fibers.

In the ozone treatment step S36, the highly water-absorbent polymer contained in the pulp fiber-containing material (treatment liquid) is oxidatively decomposed by ozone in the aqueous solution and solubilized in the aqueous solution to remove the polymer.
The state in which the superabsorbent polymer is oxidatively decomposed and solubilized in an aqueous solution means a state in which the superabsorbent polymer and the connecting structure pass through a 2 mm screen. As a result, impurities such as a super absorbent polymer can be removed from the pulp fiber-containing material (treatment liquid) to produce high-purity pulp fiber. In addition, ozone treatment can perform secondary sterilization, bleaching and deodorization of pulp fibers.

FIG. 2 is a schematic view showing an example of the configuration of the apparatus 2 that executes the ozone treatment step S36. The apparatus 2 includes a pulp fiber-containing material storage unit 3 for storing the pulp fiber-containing material 51 containing water, the pulp fiber separated in the third separation step S35, and a highly water-absorbent polymer, and the pulp fiber-containing material 51. It is provided with an ozone treatment unit 4 that oxidatively decomposes and removes the highly water-absorbent polymer contained therein from pulp fibers.

The pulp fiber-containing material storage unit 3 includes a pulp fiber-containing material tank 12 and a stirrer 13. The pulp fiber-containing material tank 12 stores the pulp fiber-containing material 51 supplied via the pipe 61. The stirrer 13 prevents the pulp fibers and the highly water-absorbent polymer in the pulp fiber-containing material 51 from separating from water and sinking below the pulp fiber-containing material 51, so that the pulp fiber-containing material 51 in the pulp fiber-containing material tank 12 does not sink. To stir.

On the other hand, the ozone treatment unit 4 includes a supply pump 21, a treatment tank 31, an ozone supply device 41, a delivery pump 22, and an ozone decomposition device 34. The treatment tank 31 has an acidic aqueous solution as the treatment liquid 52. The treatment tank 31 includes a pulp fiber-containing material supply port 32, a treatment liquid discharge port 33, and an ozone-containing gas supply port 43. The pulp fiber-containing material supply port 32 is arranged above the processing tank 31, and supplies the pulp fiber-containing material 51 to the processing tank 31. The treatment liquid discharge port 33 is arranged in the lower part of the mixing tank 31 and discharges the treatment liquid 52. The ozone-containing gas supply port 43 is arranged below the mixing tank 31, specifically, above the processing liquid discharge port 33, and sends the ozone-containing gas 53 into the processing tank 31.

Specifically, the supply pump 21 continuously connects the pulp fiber-containing material 51 of the pulp fiber-containing material tank 12 into the processing tank 31 from the pulp fiber-containing material supply port 32 at the first flow rate via the pipe 62. Supply. The ozone supply device 41 supplies the ozone-containing gas 53 to the treatment tank 31. Examples of the ozone generator 42 of the ozone supply device 41 include an ozone water exposure tester ED-OWX-2 manufactured by Ecodesign Co., Ltd., an ozone generator OS-25V manufactured by Mitsubishi Electric Corporation, and the like. The ozone-containing gas 53 is another type of gas containing ozone, and examples thereof include oxygen gas containing ozone. The ozone-containing gas supply port 43 sends the ozone-containing gas 53 supplied to the treatment tank 31 via the pipe 65 into the treatment tank 31, and is arranged at the lower part (preferably the bottom) of the treatment tank 31. The ozone-containing gas supply port 43 continuously supplies the ozone-containing gas 53 into the treatment liquid 52 as a plurality of fine bubbles from the lower part to the upper part of the treatment liquid 52 (treatment tank 31). The delivery pump 22 continuously discharges the processing liquid 52 in the processing tank 31 from the processing liquid discharge port 33 to the outside of the processing tank 31 at a second flow rate via the pipe 63. The ozone decomposition device 34 receives the ozone-containing gas 53 accumulated in the upper part of the treatment tank 31 via the pipe 64, detoxifies the ozone, and releases it to the outside. The treatment liquid 52 in the treatment tank 31 is only the treatment liquid 52 before the start of the ozone treatment step S36, and after the start, the treatment liquid 52 and the pulp fiber-containing material 51 are mixed. In the present embodiment, the liquid in the treatment tank 31 is referred to as the treatment liquid 52, including the liquid in which the treatment liquid 52 and the pulp fiber-containing material 51 are mixed.

Next, a specific method of the ozone treatment step S36 will be described.
The pulp fiber and the superabsorbent polymer separated in the third separation step S35 are mixed with water so as to have a preset concentration to obtain the pulp fiber content 51. The concentration of the pulp fiber of the pulp fiber-containing material 51 is set to a preset concentration in a state of being charged into the treatment tank 31 and mixed with the treatment liquid 52. The pulp fiber-containing material 51 is supplied to and stored in the pulp fiber-containing material tank 12 via a pipe 61. Since the specific gravity of the pulp fiber and the superabsorbent polymer is greater than 1, the pulp fiber-containing material 51 is stirred by the stirrer 13 in the pulp fiber-containing material tank 12 so that the pulp fiber and the superabsorbent polymer do not separate from water. NS.

The flow rate of the pulp fiber-containing material 51 in the pulp fiber-containing material tank 12 is controlled by the supply pump 21, and the flow rate is controlled from the pulp fiber-containing material supply port 32 to the processing tank 31 via the pipe 62 at the first flow rate. Supplied continuously. The treatment liquid 52 is an acidic aqueous solution and has a specific gravity of about 1. Therefore, the pulp fiber and the super absorbent polymer settle from the upper part to the lower part of the treatment liquid 52.

On the other hand, the ozone-containing gas 53 generated by the ozone generator 42 is supplied to the treatment tank 31 via the pipe 65, and fine bubbles (for example, micro bubbles) (for example, micro bubbles) are supplied into the treatment liquid 52 from the ozone-containing gas supply port 43 of the treatment tank 31. It is released in the state of bubbles or nanobubbles. That is, the ozone-containing gas 53 rises from the lower part to the upper part of the treatment liquid 52.

Then, in the treatment liquid 52, the pulp fibers and the superabsorbent polymer that move downward, that is, fall, and the ozone-containing gas 53 that moves upward, that is, rises, proceed in opposition to each other. Collide with each other. Then, the ozone-containing gas 53 adheres to the surface of the pulp fiber, the super absorbent polymer, and the connecting structure. Ozone in the ozone-containing gas 53 oxidatively decomposes the free superabsorbent polymer and dissolves it in the treatment liquid 52. Thereby, the super absorbent polymer on the pulp fiber is removed from the pulp fiber. Then, the pulp fiber descends to the bottom of the treatment tank 31, and the ozone-containing gas 53 escapes to the space above the treatment tank 31.

In the free superabsorbent polymer and the free pulp fiber, and the linked structure, the free superabsorbent polymer having a relatively low buoyancy and the linked structure containing the superabsorbent polymer have relatively high buoyancy. It tends to have a higher sedimentation property than free pulp fibers. On the other hand, since the ozone-containing gas consumes ozone and rises while processing the superabsorbent polymer and pulp fiber, the ozone-containing gas existing at the lower position is higher than the ozone-containing gas existing at the upper position. , Ozone content tends to be high (ie, fresh).

Therefore, the free superabsorbent polymer and the linked structure, which move downward relatively quickly, can be accurately oxidatively decomposed with a fresher ozone-containing gas to form free pulp fibers. On the other hand, since the free pulp fibers move relatively slowly downward, the ozone-containing gas can treat the free pulp fibers and the pulp fibers for the medium to be formed over time. Specifically, ozone in the ozone-containing gas collides with the pulp fibers while facing each other, so that hemicellulose, lignin, and the like of the pulp fibers (and pulp fibers for medium) can be decomposed.

After that, the treatment liquid 52 (including the pulp fiber for the medium) at the bottom of the treatment tank 31 is discharged from the treatment liquid discharge port 33 of the treatment tank 31 to the outside of the treatment tank 31 via the pipe 63 by controlling the flow rate of the delivery pump 22. It is continuously discharged at the second flow rate. The ozone of the ozone-containing gas 53 accumulated in the upper part of the treatment tank 31 is detoxified by the ozone decomposition device 34 and released to the outside.

In this way, the pulp fiber-containing material 51 is continuously supplied into the treatment tank 31 from the upper part of the treatment tank 31 at the first flow rate, and the treatment liquid 52 is continuously supplied from the lower part (bottom) of the treatment tank 31 to the treatment tank 31. It is continuously discharged to the outside at a second flow rate. Thereby, a continuous and stable flow of fluid (including pulp fibers) from the upper part to the lower part can be forcibly generated in the treatment tank 31.

The treatment liquid 52 discharged from the treatment tank 31 contains pulp fibers for a medium from which a superabsorbent polymer, hemicellulose, lignin and the like have been removed, and is a low molecular weight organic substance produced by oxidative decomposition of the superabsorbent polymer. Includes. The pulp fibers for the medium are collected in a step downstream of the delivery pump 22, for example, in a fourth separation step S37 described later.

In this method, at least the pulp fiber-containing material 51 containing the superabsorbent polymer and the superabsorbent polymer is continuously placed in the treatment tank 31 having the treatment liquid 52 capable of dissolving the superabsorbent polymer at the first flow rate. While supplying, a treatment liquid 52 containing pulp fibers for a medium from which the superabsorbent polymer has been removed and containing a low molecular weight organic substance produced by oxidative decomposition of the superabsorbent polymer is placed outside the treatment tank 31. It is continuously discharged at the second flow rate. By having such a configuration, a continuous and stable fluid from the pulp fiber-containing material supply port 32 for supplying the pulp fiber-containing material 51 in the processing tank 31 toward the processing liquid discharge port 33 for discharging the treatment liquid 52. The flow (including pulp fibers) can be forcibly generated. The flow of the fluid, that is, the water flow, allows the superabsorbent polymer to be treated (solubilized) and the pulp fibers to be treated even if the amount of the pulp fiber and the superabsorbent polymer treated is increased.

Here, it is preferable that the first flow rate and the second flow rate are the same. By making the first flow rate and the second flow rate the same, the amount of the treatment liquid 52 in the treatment tank 31 can be kept constant, and stable and continuous treatment is possible. However, if the amount of the treatment liquid 52 in the treatment tank 31 can be kept substantially constant, that is, unless the amount of the treatment liquid 52 in the treatment tank 31 is significantly increased or decreased, the first flow rate and the first flow rate. The flow rate of 2 may fluctuate with time. That is, the first flow rate and the second flow rate do not have to be completely the same at all times, and may be substantially the same on average over time. Here, substantially the same means that the difference between the first flow rate and the second flow rate is within 5% by mass. In this case as well, stable and continuous processing is possible.

When the ozone-containing gas 53 is supplied to the treatment liquid 52, the ozone concentration in the treatment liquid 52 is not particularly limited as long as it can oxidatively decompose the superabsorbent polymer, but is, for example, 1 to 50 parts by mass ppm. It is preferably 2 to 40 mass ppm, and more preferably 3 to 30 mass ppm. If the ozone concentration in the treatment liquid 52 is too low, the superabsorbent polymer cannot be completely solubilized, and the superabsorbent polymer may remain in the pulp fibers. On the contrary, if the ozone concentration in the treatment liquid 52 is too high, the oxidizing power is also increased, which may damage the pulp fibers and may cause a problem in safety. The ozone treatment temperature is not particularly limited as long as it can oxidatively decompose the superabsorbent polymer, but may be kept at room temperature or may be higher than room temperature, for example.

The concentration of ozone in the treatment liquid 52 (aqueous solution) is measured by the following method.
(1) In a 100 mL graduated cylinder containing about 0.15 g of potassium iodide and 5 mL of a 10% citric acid solution, 85 mL of a treatment solution 52 in which ozone is dissolved is put and reacted.
(2) The treatment liquid 52 after the reaction is moved to a 200 mL Erlenmeyer flask, a starch solution is added into the Erlenmeyer flask, the mixture is colored purple, and then stirred with 0.01 mol / L sodium thiosulfate until it becomes colorless. Titrate while recording the addition amount a (mL).
(3) Calculate the ozone concentration in the aqueous solution using the following formula.
The concentration of ozone (mass ppm) in the aqueous solution is calculated by the following formula:
Concentration of ozone in aqueous solution (mass ppm)
= A (mL) x 0.24 x 0.85 (mL)
Calculated by

Ozone concentration in the ozone-containing gas 53 is preferably 40~200g / ^{m 3,} more preferably from 80 to 200 g / ^{m 3,} more preferably from 100 to 200 g / ^{m 3.} If the ozone concentration in the ozone-containing gas 53 is too low, the superabsorbent polymer cannot be completely solubilized, and the superabsorbent polymer may remain. If the concentration in the ozone-containing gas 53 is too high, it may lead to damage to pulp fibers, a decrease in safety, and an increase in manufacturing cost. The ozone concentration in the ozone-containing gas 53 can be measured by, for example, an ultraviolet absorption type ozone concentration meter (for example, manufactured by Ecodesign Co., Ltd .: ozone monitor OZM-5000G).

The concentration of the pulp fiber-containing material (for example, pulp fiber and superabsorbent polymer) in the treatment liquid 52 is not particularly limited as long as it is a concentration capable of oxidatively decomposing the superabsorbent polymer by ozone in the treatment liquid 52. However, for example, 0.1 to 20% by mass is mentioned, preferably 0.2 to 10% by mass, and more preferably 0.3 to 5% by mass. If the concentration of the pulp fiber is too high, the superabsorbent polymer cannot be completely solubilized, and the superabsorbent polymer may remain in the pulp fiber. On the contrary, if the concentration of the pulp fiber is too low, the oxidizing power is also increased, which may damage the pulp fiber and may cause a safety problem. The concentrations of the pulp fibers and the superabsorbent polymer in the pulp fiber-containing material 51 are appropriately set based on the concentrations of the pulp fibers and the superabsorbent polymer in the treatment liquid 52 and the amount of the treatment liquid 52.

When ozone is supplied to the treatment liquid 52 containing the pulp fiber and the super absorbent polymer, the treatment liquid 52 is acidic (specifically, pH 0.0 or more and pH 3.0 or less, preferably pH 2.5 or more and pH 3. Less than 0), weakly acidic (specifically, pH 3.0 or higher and less than pH 6.0), or neutral (specifically, pH 6.0 or higher and pH 8.0 or lower, preferably pH 6.0 or higher and pH 7) It is preferably 0.0 or less). More preferably, the pH of the treatment liquid 52 is more than 0.0 and 7.0 or less, and more preferably 2.5 to 6.0. By treating in an acidic state, the deactivation of ozone is suppressed, the oxidative decomposition effect of the superabsorbent polymer by ozone is improved, and the superabsorbent polymer can be oxidatively decomposed in a short time. In order to maintain the pH of the treatment liquid, the pH of the pulp fiber-containing material 51 may be the same as the pH of the treatment liquid 52, and the pulp fiber-containing material 51 may be supplied to the treatment tank 31. Alternatively, the pH of the treatment liquid 52 may be monitored by a pH sensor, and when the pH fluctuates to the neutral side, a predetermined acidic solution may be added to the treatment liquid 52 in an amount corresponding to the fluctuation range.

The amount of the treatment liquid 52 (including the pulp fiber-containing material 51) in the treatment tank 31 is not particularly limited as long as it can oxidatively decompose the superabsorbent polymer, but the treatment liquid 52 in the treatment tank 31 It is preferable that the volume V (unit: L) and the mass W (unit: kg) of the pulp fiber satisfy 30 ≦ V / W ≦ 1000. More preferably, it is 50 ≦ V / W ≦ 400, and even more preferably 100 ≦ V / W ≦ 200. If the V / W is too small, the superabsorbent polymer cannot be completely solubilized and the superabsorbent polymer may remain. If the V / W is too large, the manufacturing cost may increase. The volume V of the processing tank 31 is not particularly limited, and examples thereof include 50 to 80 L.

The flow rate R ₀ (unit: L / min) of the ozone-containing gas and the volume V (unit: L) of the treatment liquid 52 in the treatment tank 31 can satisfy _{0.01 ≦ R 0 / V ≦ 1.25.} preferable. More preferably, 0.03 ≦ R _{0 /} V ≦ 1.0, and even more preferably 0.06 ≦ R _{0 /} V ≦ 0.75. If R ₀ / V is too small, the superabsorbent polymer cannot be completely solubilized, and the superabsorbent polymer may remain in the pulp fibers. If R ₀ / V is too large, it may lead to damage to pulp fibers, a decrease in safety, and an increase in manufacturing cost. _{The flow rate R0} of the ozone-containing gas is not particularly limited, and examples thereof include 3 to 6 L / min.

The time during which the pulp fiber-containing material is present in the treatment tank 31, that is, the time during which the pulp fiber-containing material is treated in the treatment liquid 52 (hereinafter, also referred to as “in-tank treatment time”) is the hemicellulose in the pulp fiber. It depends on the purpose such as decomposition of lignin, decomposition of lignin, and oxidative decomposition of highly water-absorbent polymer, and is not particularly limited. The treatment time in the tank may be short if the ozone concentration of the treatment liquid 52 is high, and long if the ozone concentration of the treatment liquid 52 is low. The treatment time in the tank includes, for example, 15 minutes to 180 minutes, preferably 30 minutes to 60 minutes.

The ozone-containing gas and the pulp fiber-containing material can be brought into contact with each other based on the CT value, which is the product of the ozone concentration (mass ppm) in the treatment liquid and the treatment time (minutes) in the tank. The CT value is preferably 6,000 to 12,000 ppm / min, more preferably 8,000 to 11,000 ppm / min, and even more preferably 9,000 to 10,000 ppm / min. If the CT value is too small, decomposition of hemicellulose, decomposition of lignin, decomposition of superabsorbent polymer, particularly decomposition of hemicellulose may be insufficient. If the CT value is too large, it may lead to damage to pulp fibers, reduced safety, and increased manufacturing costs.

The method for measuring the ozone concentration in the CT value is as described above.
Further, the in-tank processing time in the CT value means the time (minutes) of supplying the ozone-containing gas in the case of the so-called batch type. In the case of the so-called continuous type, the treatment time in the tank means a value obtained by dividing the volume (L) of the treatment liquid in the treatment tank by the discharge amount (L / min) per hour.

While the pulp fibers are present in the treatment tank 31, the superabsorbent polymer is oxidatively decomposed into low molecular weight components by ozone and dissolved in the treatment liquid 52. Further, ozone decomposes hemicellulose in the pulp fiber, and a part of the hemicellulose is dissolved in the treatment liquid 52. In addition, ozone decomposes lignin in the pulp fiber and dissolves it in the treatment liquid 52. The low molecular weight component of the superabsorbent polymer, the decomposition product of hemicellulose, the decomposition product of lignin, etc. dissolved in the treatment liquid 52 are discharged together with the treatment liquid 52. Further, in this step, the bactericidal action of ozone primary disinfects used hygiene products.

The manufacturing method of the present disclosure includes the following steps.
-A medium having a hemicellulose content of less than 8.0% by mass from the pulp fibers to be treated by supplying an ozone-containing gas to a treatment tank containing a treatment liquid containing a pulp fiber-containing material containing pulp fibers to be treated. Pulp fiber formation step for medium to form pulp fiber for medium

In the pulp fiber forming step for a medium, hemicellulose of less than 8.0% by mass is supplied from pulp fibers by supplying an ozone-containing gas to a treatment tank containing a treatment liquid containing a pulp fiber-containing material containing pulp fibers to be treated. It is not particularly limited as long as it forms pulp fibers for a medium having a content rate, and for example, it can be carried out by a so-called batch type, continuous type or the like.

When the pulp fiber to be treated is an unused pulp fiber, the pulp fiber-containing material can be an unused pulp fiber alone.
When the pulp fiber to be treated is a used pulp fiber, for example, a pulp fiber derived from a used sanitary product, the pulp fiber-containing material contains at least the pulp fiber, and even if it is a pulp fiber alone. good. Further, the pulp fiber-containing material can contain a superabsorbent polymer in addition to the pulp fiber, and constitutes a connecting structure in which a plurality of superabsorbent polymers and a plurality of pulp fibers are connected, and sanitary goods. Materials (eg, core wrap, liquid permeable sheet, liquid permeable sheet, etc.) and the like may be included.
The ozone-containing gas may be supplied into the treatment liquid in the treatment tank, or may be supplied to the space on the treatment liquid in the treatment tank.

The production method of the present disclosure can include the following preparation step, pulp fiber content supply step, ozone-containing gas supply step, pulp fiber formation step for medium, and treatment liquid discharge step.
-Preparation step to prepare the treatment tank having a pulp fiber-containing material supply port, a treatment liquid discharge port, and an ozone-containing gas supply port arranged at a position below the treatment tank.-Preparation step-The pulp fiber-containing material , Pulp fiber-containing material supply step to be supplied to the treatment tank from the pulp fiber-containing material supply port-The ozone-containing gas is supplied to the treatment liquid in the treatment tank from the ozone-containing gas supply port. Gas supply step-In the treatment tank, while raising the ozone-containing gas, the pulp fiber-containing material is brought into contact with the ozone-containing gas to form the pulp fiber for the medium from the pulp fiber to be treated. Pulp fiber formation step for medium-The treatment liquid containing the pulp fiber for the medium is discharged from the treatment liquid discharge port, and the treatment liquid discharge step.

The treatment liquid discharge port is arranged below the pulp fiber-containing material supply port, and in the pulp fiber forming step for a medium, the pulp fiber-containing material is brought into contact with the ozone-containing gas while lowering the pulp fiber-containing material. The treatment liquid discharge port may be arranged above the pulp fiber content supply port, and the pulp fiber content may be raised while raising the pulp fiber content in the pulp fiber formation step for a medium. It may be brought into contact with an ozone-containing gas.

In the present embodiment, as one of the embodiments, the ozone treatment step S36 (continuous treatment step) continuously supplies the pulp fiber-containing material 51 from the upper part of the treatment tank 31 while supplying the treatment liquid 52 to the treatment tank. It includes a step of continuously discharging from the lower part of 31. The pulp fiber and the superabsorbent polymer in the pulp fiber-containing material 51 have low buoyancy, and the pulp fiber and the superabsorbent polymer and the connecting structure naturally settle.

In the present embodiment, as one of the embodiments, the treatment liquid 52 capable of dissolving the superabsorbent polymer is an aqueous solution containing an ozone-containing gas that oxidatively decomposes the superabsorbent polymer so as to be soluble. The ozone treatment step S36 (continuous treatment step) further includes a delivery step of continuously sending out a plurality of bubbles of the ozone-containing gas from the lower part to the upper part of the treatment liquid 52. In one of such aspects of the method, in the treatment liquid 52, the ozone-containing gas rises and the pulp fibers and the superabsorbent polymer fall, that is, countercurrent. Thereby, the contact probability between the pulp fiber and the super absorbent polymer and the ozone-containing gas can be increased. Also, the deeper the pulp fibers and superabsorbent polymer settle, the higher the concentration of ozone-containing gas can be contacted. Therefore, the superabsorbent polymer, hemicellulose, lignin, etc., which could not be completely dissolved in the treatment liquid 52 only by the ozone-containing gas contacted in the shallow part of the treatment liquid 52, come into contact with the high-concentration ozone-containing gas in the treatment liquid 52 in the deep part. Can be made to. Thereby, the super absorbent polymer, hemicellulose, lignin and the like can be decomposed, dissolved in the treatment liquid 52, and removed from the pulp fibers.

In the present embodiment, as one of the embodiments, the above-mentioned delivery step includes a step of sending ozone-containing gas in the state of microbubbles or nanobubbles. However, the microbubbles are bubbles having a diameter of about 1 to 1000 μm, preferably about 10 to 500 μm, and the nanobubbles are bubbles having a diameter of about 100 to 1000 nm, preferably about 100 to 500 nm. Microbubbles or nanobubbles are such fine bubbles, have a large surface area per unit volume, and have a property that the rate of rise in the liquid is slow. Therefore, in this method, as one of the embodiments, the ozone-containing gas having such fine bubbles is sent from the lower part to the upper part of the treatment liquid 52 in the treatment tank 31.

On the other hand, the pulp fiber and the super absorbent polymer move from the top to the bottom. At this time, since the rising rate of the fine bubbles is slow, the probability that the bubbles come into contact with the pulp fibers can be increased. Further, since the fine bubbles occupy a small area on the surface of the pulp fiber, more bubbles can come into contact with the surface of the pulp fiber. Thereby, the pulp fiber, the superabsorbent polymer, and the connecting structure can be evenly wrapped with fine bubbles, and the contact area between them and the ozone-containing gas can be further increased. In addition, when the pulp fiber-containing material is lowered in the pulp fiber forming step for a medium, more bubbles come into contact with the surface of the pulp fibers, and the buoyancy of the bubbles causes the pulp fibers and the superabsorbent polymer, as well. It is possible to reduce the sedimentation property of the linked structures and further increase the contact time between them and the ozone-containing gas. Thereby, the super absorbent polymer, hemicellulose, lignin and the like can be decomposed, dissolved in the treatment liquid 52, and removed from the pulp fibers.

In the present embodiment, as one of the embodiments, the treatment liquid 52 is an acidic aqueous solution, for example, an acidic aqueous solution having a pH of 2.5 or less. In that case, even if the superabsorbent polymer in the pulp fiber-containing material 51 partially has a water-absorbing capacity, the water-absorbing expansion of the superabsorbent polymer can be suppressed. As a result, the superabsorbent polymer can be dissolved in the treatment liquid 52 in a short time, and the superabsorbent polymer can be removed more reliably. In particular, when the treatment liquid 52 is an ozone-containing aqueous solution, ozone in the ozone-containing aqueous solution can be hardly deactivated, so that the superabsorbent polymer can be oxidatively decomposed in a shorter time, and hemicellulose, lignin, etc. can be produced. It can be disassembled.

Further, as another preferred embodiment, the configuration of the treatment tank 31 may be a configuration other than that shown in FIG. FIG. 3 is a schematic view showing another configuration example of the apparatus 2 in the ozone treatment step of FIG. Compared with the device 2 of FIG. 2, the device 2 of FIG. 3 has a continuous U-shaped tube structure in which the pipe 63 of the ozone treatment unit 4 connects two U-shaped tubes upside down and continuously to each other. The difference is that the delivery pump 22 is omitted. In that case, the pipe 63 is filled with the treatment liquid 52, and the height of the liquid level of the treatment liquid 52 in the treatment tank 31 is higher than the height of the liquid level in the tank of the next step connected by the pipe 63. If it is high, the treatment liquid 52 is discharged to the tank in the next step via the pipe 63 according to the siphon principle. Therefore, if the height of the liquid level of the treatment liquid 52 in the treatment tank 31 and the height of the liquid level of the liquid in the tank of the next step are initially set to be the same before the start of the treatment, the treatment is started by the start of the treatment. When the pulp fiber-containing material 51 is continuously supplied into the tank 31 at the first flow rate, the treatment liquid 52 is discharged to the tank in the next step through the pipe 63 at the second flow rate = the first flow rate according to the siphon principle. Will be done. However, regarding the height of the liquid level in the tank in the next step, the height before the start of the treatment should be maintained even during the treatment. In this case, the delivery pump 22 is unnecessary, and the control of the second flow rate of the delivery pump 22 becomes unnecessary.

In the present embodiment, the separation step S13 further includes a fourth separation step S37 for separating the pulp fibers from the treatment liquid 52 discharged from the treatment tank 31, and a second drying step for drying the separated pulp fibers. S38 and may be included.

In the fourth separation step S37, the method for separating the pulp fibers from the treatment liquid 52 discharged from the treatment tank 31 is not particularly limited, but for example, the treatment liquid 52 containing the pulp fibers for a medium is opened, for example. A method of passing a screen mesh of 0.15 to 2 mm can be mentioned. When the treatment liquid 52 containing pulp fibers for medium is passed through a screen mesh with an opening of 0.15 to 2 mm, the wastewater containing oxidative decomposition products of superabsorbent polymer, hemicellulose decomposition products, lignin decomposition products, etc. is screened. pass. On the other hand, the pulp fibers for the medium remain on the screen.

In the subsequent second drying step S38, the separated pulp fibers are dried in a high temperature atmosphere, hot air, or the like to form pulp fibers for a medium. The drying temperature is, for example, 105 to 210 ° C, preferably 110 to 190 ° C. The drying time depends on the drying temperature, but is, for example, 10 to 120 minutes, preferably 15 to 100 minutes. As a result, the water remaining on the surface of the pulp fiber is evaporated and removed, and the pulp fiber for a medium having a very low superabsorbent polymer content and a high purity can be recovered. Further, the pulp fibers for the medium can be sterilized (disinfected) in a high temperature atmosphere or hot air.
When the cellulase production step is performed without storing the pulp fibers for the medium, the second drying step S38 can be omitted.

In the present disclosure, the pulp fibers for the medium have a hemicellulose content of less than 8.0% by mass, and preferably 7.0% by mass or less, more preferably 6.5% by mass or less, and even more preferably 6. It has a hemicellulose content of 0% by mass or less. Thereby, cellulase can be efficiently produced from the pulp fiber for the medium. The lower limit of the hemicellulose content is 0.0% by mass.

In the present disclosure, the pulp fiber for medium has a lignin content of preferably 0.10% by mass or less, more preferably 0.08% by mass or less, and even more preferably 0.06% by mass or less. Thereby, cellulase can be efficiently produced from the pulp fiber for the medium. The lower limit of the lignin content is 0.00% by mass.

In the present disclosure, the pulp fiber for a medium preferably has a cellulose content of 87.0% by mass or more, more preferably 90% by mass or more, and even more preferably 93% by mass or more. Thereby, cellulase can be efficiently produced from the pulp fiber for the medium. The upper limit of the cellulose content of the pulp fiber for the medium is 100.0% by mass.

In the present disclosure, the cellulose content, hemicellulose content and lignin content in the pulp fiber for a medium can be measured according to a known detergent analysis method.

In the present disclosure, the pulp fiber for medium has a beating degree reduction rate of preferably 300 mL or more, more preferably 320 mL or more, still more preferably 340 mL or more, and even more preferably 360 mL or more. Thereby, in the cellulase production step, cellulase can be efficiently produced due to the fluffiness (large surface area) of the pulp fiber for the medium.

In the production method of the present disclosure, the pulp fiber for medium has a beating degree reduction rate of preferably 990 mL or less, more preferably 800 mL or less, still more preferably 700 mL or less, and even more preferably 600 mL or less. By doing so, it is possible to prevent the pulp fibers for the medium from becoming difficult to recover.
The rate of decrease in beating degree is obtained by a low hemicellulose content, a low lignin content, etc. in the pulp fiber for a medium.

The beating degree reduction rate is measured according to the following beating degree reduction test.
<Deterioration test>
(1) Pulp fibers for medium are beaten for 1 hour or more, preferably 2 hours according to JIS P 8221-1: 1998 pulp-beating method-Part 1: beater method.
(2) Samples are taken every 20 minutes after the start of beating, and the beating degree of each sample is determined according to JIS P 811-2: 2012 pulp-water freshness test method-Part 2: Canadian standard free-water degree method. Canadian standard freshness, Canadian Standards) is measured. The test may be stopped when the beating degree of the sample is less than 100 mL.
(3) Plot time (h) on the horizontal axis and beating degree (mL) on the vertical axis, approximate it to a linear function by the least squares method, and use the absolute value of the slope as the beating degree decrease rate (mL / m). adopt.
The rate of decrease in beating degree means that the larger the value is, the faster the decrease in beating degree per unit time is, that is, the pulp fibers for the medium are easily beaten (prone to fluffing).

In the present disclosure, the pulp fibers for a medium preferably have a water contact angle of 20 ° or less, more preferably 15 ° or less, and even more preferably 10 ° or less. By doing so, after the pulp fiber for a medium produced by the above-mentioned production method is dried and stored, water can be easily added when forming a medium for a cellulase-producing bacterium in a cellulase production step. From the above viewpoint, the water contact angle of the pulp fiber for the medium may be 0 °.

The water contact angle of the pulp fiber for the medium can be measured as follows.
(1) Dry with an aluminum ring (outer diameter: 43 mm, inner diameter: 40 mm, height: 5 mm) in a constant temperature and humidity chamber with a temperature of 20 ± 5 ° C and a humidity of 65 ± 5% RH for 60 minutes at 120 ° C. Prepare the pulp fiber for saccharification and let stand for 24 hours.
(2) 1.5 g of pulp fiber for medium is evenly filled in an aluminum ring, and the pulp fiber for medium is compressed together with the aluminum ring for 1 minute at a pressure of 3 Mpa using a press machine with a smooth bottom surface. Then, the surface of the pulp fiber for the medium is smoothed.
(3) The water contact angle of the compressed pulp fiber for the medium was set to 6. Measure according to the intravenous drop method. Examples of the contact angle measuring device include an automatic contact angle meter CA-V type manufactured by Kyowa Interface Science Co., Ltd. The water contact angle means a value 200 ms after dropping deionized water.
(4) The water contact angle is measured in 20 different samples, and the average value thereof is adopted.

In the present disclosure, the pulp fibers for the medium are preferably 0.65% by mass or less, more preferably 0.50% by mass or less, still more preferably 0.30% by mass, and even more preferably 0.20% by mass or less. Has an ash content. By doing so, when forming a medium for cellulase-producing bacteria using pulp fibers for a medium, metal ions and their precipitates are less likely to damage the equipment.
The ash content is reduced, for example, by selecting an acid capable of forming a complex with a metal ion contained in excrement as an inactivating agent, particularly citric acid, in the inactivating step S31 for inactivating a super absorbent polymer. Can be done.

In the present specification, the ash content means the amount of the inorganic or nonflammable residue left after the organic matter is ashed, and the ash content means the ratio (mass ratio) of the ash content contained in the material to be promoted. do. The ash content is measured according to "5. Ash content test method" of "2. General test method" of the material standard for physiological treatment products. Specifically, the ash content is measured as follows.
(1) A platinum, quartz or porcelain crucible is preheated at 500 to 550 ° C. for 1 hour, allowed to cool, and then its mass is precisely weighed.
(2) Collect 2 to 4 g of pulp fiber for medium dried at 120 ° C. for 60 minutes, put it in a crucible, weigh it precisely, remove or shift the lid of the crucible if necessary, and heat it weakly at first. The temperature is gradually increased and the mixture is heated at 500 to 550 ° C. for 4 hours or more to incinerate until no carbide remains.
(3) After allowing to cool, weigh the mass precisely. The residue is ashed again until it reaches a constant weight, and after allowing to cool, its mass is precisely weighed to obtain the ash content (mass%).

In the present disclosure, the pulp fibers for the medium are preferably not detected by Bacillus cereus and Bacillus subtilis, more preferably Bacillus spp., And even more preferably bacteria by the pour culture method.

Bacillus spp., For example, Bacillus cereus and Bacillus subtilis are indigenous bacteria that are universally present in soil, water, plants, etc., and are extremely durable because they form spores. .. Spores are highly resistant to heat, disinfectants, etc., and may not be completely removed by general disinfection methods, which may inhibit cellulase-producing bacteria from producing cellulase.

Examples of bacteria that can be detected by the pour culture method include general viable bacteria such as Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, non-fermenting bacilli of glucose, and Aeromonas.

Bacteria, specifically, general viable bacteria, are not detected by the pour culture method, so that the activity of cellulase-producing bacteria is inhibited when cellulase is produced using a cellulase-producing bacterium medium containing pulp fibers for the medium. It becomes difficult to be done. Therefore, the pulp fiber for the medium is excellent in the productivity of cellulase because bacteria and the like are not detected from the pulp fiber for the medium.

Further, it is preferable that bacteria are not detected in the pulp fiber for the medium by the plate culture method. By not detecting bacteria, specifically intestinal bacteria, by the plate culture method, the activity of cellulase-producing bacteria is inhibited when cellulase is produced using a cellulase-producing bacterium medium containing pulp fibers for the medium. It becomes difficult. Therefore, the pulp fiber for the medium is excellent in the productivity of cellulase because bacteria and the like are not detected from the pulp fiber for the medium.

Examples of the intestinal bacteria include Escherichia coli, Klebsiella oxytoca, Citrobacter freundii, and Klebsiella spp. , Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, Enterobacter spp. , Enterobacter aerogenes, Morganella morganii, Providencia rettgeri and the like.

The culture method including the plate culture method and the pour culture method is carried out as follows.
(1) In a 1-liter beaker, 500 g of an aqueous dispersion having a solid content concentration of 5.0% by mass of pulp fibers for a medium is prepared.
When the pulp fiber for medium is present in a dry state, the aqueous dispersion contains pulp fiber for medium (25.0 g as a solid content) and deionized water (amount having a total amount of 500.0 g). It can be formed by mixing. When the pulp fiber for medium is present in an aqueous solution (for example, when the pulp fiber for medium is recovered as an aqueous solution in the method for producing pulp fiber for medium), the solid content concentration of the pulp fiber for medium is 5 When the content is 0.0% by mass or more, an aqueous dispersion having a solid content concentration of 5.0% by mass can be prepared by adding deionized water to the aqueous solution or the like.

Further, when the culture medium pulp fiber is present in an aqueous solution and the solid content concentration of the culture medium pulp fiber is less than 5.0% by mass, the solid content concentration of the culture medium pulp fiber is increased by filtration. Adjust to 0% by mass, or use the aqueous solution itself as an aqueous dispersion to increase the inoculum of the serially diluted sample described below (for example, when the solid content concentration of the medium pulp fiber is 2.5% by mass). Can double the inoculum).

(2) The aqueous dispersion is stirred for 15 minutes at a rotation speed of 300 rpm using an overhead stirrer.
(3) 50 mL of the aqueous dispersion stirred with an overhead stirrer is placed in a sterilization bag with a filter (manufactured by LMS, a sterilization bag with a filter for a homogenizer) and stirred for 5 minutes.
(4) The filtered aqueous dispersion filtered through a sterilized bag with a filter is dispensed into a sterilized test tube, ^{diluted 10-fold in steps to 10-9} , dispensed into a sterilized test tube, and a serially diluted sample. Prepare.

(5-1) The number of intestinal bacteria is measured by a plate culture method.
Specifically, 0.1 mL of each of the serially diluted samples is inoculated into a BTB lactose-added agar medium (manufactured by Nippon Becton Dickinson, 251251), the serially diluted samples are applied with a spreader, and the cells are cultured at 35 ° C. for 24 hours. ..
(5-2) The number of general viable bacteria is measured by a pour culture method.
Specifically, 1 mL of a serially diluted sample and a standard agar medium (manufactured by Nihon Pharmaceutical Co., Ltd., 396-00175 SCD agar medium "Daigo" for general viable cell test, 15 to 20 g) are placed in a petri dish and mixed at 35 ° C. for 48 hours. Agar culture.

(6) For each of the number of intestinal bacteria and the number of general viable bacteria, the number of colonies that have grown after culturing is counted.
When the number of colonies is zero in all the serially diluted samples diluted 10-fold to ^{10-9, it is determined that the target bacterium is "not detected".}
(7) When colonies of enterobacteria or general viable bacteria are formed after culturing, the type of bacteria can be identified. Identification can be performed by a biochemical property test method.

In the present embodiment, as a preferred embodiment, before the ozone treatment step S36 (continuous treatment step), the mixture is treated with an aqueous solution capable of inactivating the water absorption performance of the highly water-absorbent polymer to treat the mixture with high water absorption in the mixture. Before the inactivating step S31 for inactivating the water absorption performance of the sex polymer and the ozone treatment step S36 (continuous treatment step), the first separation for separating the inactivated highly water-absorbent polymer and the pulp fiber from the aqueous solution. The process S32 is further provided. As described above, in the present method, as a preferred embodiment, in the inactivation step S31, the water absorption performance of the superabsorbent polymer is suppressed by the aqueous solution capable of inactivating the water absorption performance of the superabsorbent polymer. At the stage of step S36 (continuous treatment step), the superabsorbent polymer can be more easily dissolved by the treatment liquid 52 in a short time.

In the present embodiment, as a preferred embodiment, in the inactivating step S31, the aqueous solution capable of inactivating the water absorption performance of the superabsorbent polymer is an acidic aqueous solution, for example, an acidic aqueous solution having a pH of 2.5 or less. As described above, in the present method, as a preferred embodiment, since the aqueous solution capable of inactivating the water absorption performance of the superabsorbent polymer is an acidic aqueous solution, the superabsorbent polymer is more easily inactivated, whereby in the stage of the inactivation step S31. , The water absorption performance of the super absorbent polymer can be suppressed more reliably. As a result, the superabsorbent polymer can be more easily dissolved in the treatment liquid for a short time at the stage of the ozone treatment step S36 (continuous treatment step) in the subsequent step.

Further, as another preferred embodiment, the treatment tank 31 may include at least a first treatment tank 31-1 and a second treatment tank 31-2 connected in series with each other. FIG. 4 is a schematic view showing another configuration example of the apparatus 2 in the ozone treatment step of FIG. Compared with the device 2 of FIG. 2, the device 2 of FIG. 4 has two ozone treatment units 4 bonded in series, in other words, the first treatment tank 31-1 and the second treatment tank 31. The difference is that -2 is joined in series. In that case, for example, the first treatment tank 31-1 is supplied with the pulp fiber-containing material 51, the first treated liquid (treatment liquid 52-1 of the first treatment tank 31-1) is discharged, and the first treatment tank 31-1 is discharged. The treatment tank 31-2 of 2 is supplied with the first treated liquid and discharges the second treated liquid (treatment liquid 52-2 of the second treatment tank 31-2), and so on. The inclusion 51 is treated in multiple stages. In that case, as compared with the case where one treatment tank 31 having a large capacity is provided, the treatment is performed with new treatment liquids 52-1 and 52-2 for each of the first and second treatment tanks 31-1 and 31-2. Therefore, for example, the superabsorbent polymer that could not be completely dissolved in the first treatment tank (first stage treatment tank) 31-1 can be easily dissolved in the second treatment tank (next stage treatment tank) 31-2. Etc., the super absorbent polymer can be dissolved more reliably and can be removed from the fiber.

Further, as another preferred embodiment, the treatment tank 31 may include an ejector. For example, the ejector includes a drive fluid supply port, a mixed fluid discharge port connected to the treatment tank, and a suction fluid supply port between them, and supplies the pulp fiber-containing material 51 with the drive fluid of the ejector. A mixed solution formed by supplying ozone to the suction fluid supply port while supplying the port and mixing the pulp fiber-containing material 51 and ozone in the ejector is supplied from the mixed fluid discharge port. It is discharged into the treatment liquid in the treatment tank.

By supplying the pulp fiber-containing material 51 as the driving fluid and ozone as the suction fluid to the ejector and mixing them in the ejector, the pulp fiber-containing material 51 and ozone are mixed very well as a mixed fluid. Can efficiently form a mixed solution of. That is, a mixed solution in which the pulp fiber-containing material 51 and ozone are extremely close to each other can be formed. Then, the treatment liquid can be agitated by discharging the mixed liquid into the treatment liquid in the treatment tank. Further, when ozone is discharged into the treatment liquid, it is continuously discharged in the state of fine bubbles, so that ozone can be diffused extremely widely in the treatment liquid. As a result, not only the pulp fiber-containing material 51 in the mixed liquid discharged from the ejector, but also the pulp fiber containing the super absorbent polymer in the treatment liquid in the treatment tank, the superabsorbent polymer and the gaseous substance Reaction can proceed extremely efficiently.

In the present embodiment, as a preferred embodiment, in the material separation step S1, in the pretreatment step S11, the used sanitary goods are kept in the same shape without breaking and the superabsorbent polymer is not inactivated. Can be made very inflated with water. As a result, a very high internal pressure can be generated in the used hygiene product, and any part of the surface thereof can be in a state where it is likely to be torn off. Then, in the disassembly step S12, by applying a physical impact to the used sanitary goods in such a state, any part of the surface thereof is torn and the internal absorption core is ejected to the outside. be able to. Thereby, the used hygiene product can be decomposed into at least a film (liquid permeable sheet) and an absorption core. At this time, since the film generally maintains its original shape, it can be easily separated from the absorption core in the subsequent separation step S13. As a result, the constituent member such as a film can be separated from other constituent members while maintaining the same shape without breaking or the like. Therefore, constituent members such as films for hygiene products can be efficiently recovered.

In the present embodiment, as a preferred embodiment, by using a terpene for removing the adhesive, the hot melt adhesive for adhering the constituent members of the sanitary goods can be melted at room temperature. As a result, the hygiene product can be easily and neatly separated, the pulp fiber and the superabsorbent polymer can be separated from the hygiene product, and the non-woven fabric and the film can be separated separately while leaving the member form. That is, the pulp fibers, films, and non-woven fabrics can be easily recovered separately without crushing the sanitary products or going through a complicated separation process. When limonene is used as a terpene, it has a refreshing citrus odor as a side effect of limonene, so that the odor derived from excrement can be covered to some extent, and the odor burden on workers and the influence of odor on the neighborhood can be reduced. .. Limonene is a monoterpene and is similar in structure to styrene, so it can dissolve styrene-based hot melt adhesives commonly used in hygiene products. Since sanitary goods can be cleaned at room temperature, energy costs can be reduced and the generation and diffusion of odors can be suppressed. Terpenes have a high oil stain cleaning effect, and in addition to the effect of dissolving hot melt adhesives, if there is printing on the film, the printing ink can also be decomposed and removed, and the printed film can also be recovered as a high-purity plastic material. Is.

Further, when an organic acid aqueous solution having a pH of 2.5 or less is used for inactivating the super absorbent polymer, the pulp fibers are hardly deteriorated. When citric acid is used as the organic acid, the effect of removing stain components derived from excrement can be expected due to the chelating effect and detergency of citric acid. In addition, a sterilizing effect and a deodorizing effect on alkaline odors can be expected.

Furthermore, by oxidatively decomposing the superabsorbent polymer with ozone, it is possible to prevent contamination of pulp fibers and a rapid increase in sewage due to water absorption of the superabsorbent polymer. By adjusting the ozone concentration, it is possible to simultaneously perform oxidative decomposition and sterilization of superabsorbent polymers. In addition, when ozone is used, no chlorine-based chemicals are used, so it is possible to produce high-quality RPF that does not easily damage the combustion furnace from the recovered plastic members. Since no salts are used during the treatment process, there is no residue on the pulp fibers, and high quality medium pulp fibers with low ash content can be recovered.

The production method of the present disclosure can further include a cellulase production step of producing cellulase using the pulp fibers for the medium after the pulp fiber formation step for the medium, for example, after the treatment liquid discharge step. The cellulase production step is not particularly limited as long as it produces cellulase, and includes a cellulase production method known in the art. Examples of the cellulase production method include the methods described in JP-A-2008-0929110, JP-A-2011-152079, JP-A-2013-202021 and the like.

As shown in FIG. 1, the cellulase production step can be carried out by subjecting the dried pulp fibers for medium obtained in the second drying step S38 to the cellulase production step, or the fourth separation. It may be carried out by subjecting the undried pulp fiber for medium obtained in step S37 to the cellulase production step. Although it is possible to use the treatment liquid 52 containing the pulp fibers for the medium obtained in the ozone treatment step S36 in the cellulase production step, it is preferable because the remaining ozone may affect the cellulase-producing bacteria. is not it.

[Manufacturing Example 1]
Pulp fibers for culture medium were produced from a plurality of used disposable diapers collected from a long-term care facility according to the methods shown in FIGS. 1 and 2. The conditions related to the ozone treatment step S36 were as follows.
(I) Pulp fiber-containing material 51
-Concentration: 1% by mass (concentration of pulp fiber and super absorbent polymer)
-PH: 2.4
(Ii) Treatment tank 31
・ Capacity: 60L
・ Height: 2.6m
-First flow rate: 2 L / min-Second flow rate: 2 L / min-In-tank processing time: 30 minutes-V / W: 100
・ R ₀ / V: 0.033
(Iii) Ozone-containing gas / ozone concentration: 200 g / m ³
・ Form: Nano bubbles

The inactivation step S31 was carried out with citric acid having a pH of 2.0, and the ozone treatment step S36 was carried out under the above-mentioned conditions. I got 1.

[Reference manufacturing example 1]
Pulp fiber No. 1 for medium was the same as in Production Example 1 except that the treatment time in the tank was changed to 15 minutes. I got 2.
[Comparative Manufacturing Example 1]
NBKP virgin pulp fiber was used as a medium pulp fiber No. It was set to 3.

[Example 1, Reference Example 1, and Comparative Example 1]
Pulp fiber for medium No. 1-No. The cellulose content, hemicellulose content, lignin content (mass%), and ash content (mass%) of No. 3 were measured. The results are shown in Table 1.

[Manufacturing Example 2]
A total of 1400 used disposable diapers (about 250 kg) collected from a nursing care facility for the elderly were crushed using a Sumitomo Cutter (manufactured by Sumitomo Heavy Industries Environment Co., Ltd.) as a crushing device, and an aqueous solution containing crushed material was prepared. Formed. As the inactivating aqueous solution, about 1 ton of a 0.16 mass% calcium hydroxide aqueous solution was used.
The crushed material-containing aqueous solution is introduced into the horizontal washing machine ECO-22B (manufactured by Inamoto Manufacturing Co., Ltd.) as the first separation device to separate the pulp fibers and the superabsorbent polymer from the other constituent materials, and the pulp is separated. An aqueous solution containing fibers and a super absorbent polymer was formed. Then, the aqueous solution containing the pulp fiber and the super absorbent polymer was passed through a dust remover and then moved to a stirring tank.

A 2% by mass citric acid aqueous solution is added to the stirring tank so that 1 part by mass of citric acid is added per 1 part by mass of the solid content of the pulp fiber, and the contents of the stirring tank are moved to the ozone treatment device. Then, ozone treatment and ejector treatment were performed to decompose the highly water-absorbent polymer. A part of the contents that had passed through the ozone treatment device was extracted to form a sample. The solid content concentration of the sample was about 2% by mass. The sample was dehydrated and its solid content concentration was adjusted to about 5% by mass.

In the ozone treatment step using the ozone treatment device (twice in total), the ozone concentration at the first time was 200 g / m ³ , and the ozone supply amount was 100 g / h. The ozone concentration in the second time was 200 g / m ³ , and the ozone supply amount was 100 g / h.
The sample sample whose solid content concentration was adjusted to about 5% by mass was centrifuged using a micro-cooled centrifuge (Model 3740 manufactured by Kubota Shoji Co., Ltd., rotation speed: 12,000 rpm, temperature: 4 ° C., time: 5 minutes). Then, sample No. 1 was formed.

[Comparative Manufacturing Example 2]
About 15 kg of 100 used paper diapers collected from the elderly care facility are put into the sterilized stirring container, and then the concentration of pulp fiber (3 kg) is adjusted to about 5% by mass in the stirring container. 600 kg of sterilized water was put into the container, the contents of the container were stirred for 10 minutes, and the aqueous solution in the container was mixed with Sample No. It was set to 2.

Sample No. 1 and sample No. The number of bacteria of 2 was measured by the pour culture method and the plate culture method described in the present specification. The results are shown in Table 2. In addition, the major bacterial types were identified by biochemical property testing. The results are shown in Table 2.
In Table 2, ND means that it is not detected.

When confirmed by the biochemical property inspection method, the sample No. Most of the general viable bacteria contained in 2 were Bacillus cereus, and Bacillus cereus was also included. Sample No. Neither Bacillus cereus nor Bacillus subtilis was detected in 1 (sample sample).
From the above, it can be seen that by treating disposable diapers with ozone-containing gas, it is possible to eliminate general bacteria in the pour culture method and intestinal bacteria in the plate culture method.

31 Treatment tank 32 Pulp fiber-containing material supply port 33 Treatment liquid discharge port 43 Ozone-containing gas supply port 51 Pulp fiber-containing material 52 Treatment liquid 53 Ozone-containing gas S36 Ozone treatment process

Claims (20)

A method for producing a pulp fiber for a medium as a medium for a cellulase-producing bacterium from a pulp fiber to be treated.
By supplying an ozone-containing gas to a treatment tank containing a treatment liquid containing a pulp fiber-containing material containing pulp fibers to be treated, the pulp fibers to be treated have a hemicellulose content of less than 8.0% by mass. Pulp fiber formation step for medium, forming pulp fiber for medium,
The method described above, wherein the method comprises. The method according to claim 1, wherein the pulp fiber for a medium has a lignin content of 0.10% by mass or less. The method according to claim 1 or 2, wherein the pulp fiber for a medium has an ash content of 0.65% by mass or less. The method according to any one of claims 1 to 3, wherein bacteria are not detected in the pulp fiber for a medium by a pour culture method and / or a plate culture method. In the pulp fiber forming step for a medium, the ozone-containing gas is brought into contact with the pulp fiber-containing material so that the CT value, which is the product of the ozone concentration and the treatment time, is 6,000 to 12,000 ppm · min. The method according to any one of claims 1 to 4, wherein the pulp fibers for a medium are formed by allowing the pulp fibers to be formed. The above method is the next step,
Preparation step, which prepares the treatment tank including a pulp fiber-containing material supply port, a treatment liquid discharge port, and an ozone-containing gas supply port arranged at a position below the treatment tank.
A pulp fiber-containing material supply step in which the pulp fiber-containing material is supplied to the processing tank from the pulp fiber-containing material supply port.
An ozone-containing gas supply step in which the ozone-containing gas is supplied from the ozone-containing gas supply port to the treatment liquid in the treatment tank.
In the treatment tank, the pulp fiber-containing material is brought into contact with the ozone-containing gas while raising the ozone-containing gas to form the pulp fiber for the medium from the pulp fiber to be treated. Fiber formation step,
A treatment liquid discharge step in which the treatment liquid containing the pulp fibers for a medium is discharged from the treatment liquid discharge port.
The method according to any one of claims 1 to 5, wherein the method comprises. The treatment liquid discharge port is arranged below the pulp fiber-containing material supply port.
In the pulp fiber forming step for a medium, the pulp fiber-containing material is brought into contact with the ozone-containing gas while lowering the pulp fiber-containing material.
The method according to claim 6. The treatment liquid discharge port is arranged above the pulp fiber-containing material supply port.
In the pulp fiber forming step for a medium, the pulp fiber-containing material is brought into contact with the ozone-containing gas while raising the pulp fiber-containing material.
The method according to claim 6. In the pulp fiber-containing material supply step, the pulp fiber-containing material is continuously supplied from the pulp fiber-containing material supply port to the treatment tank at a first flow rate, and in the treatment liquid discharge step, the treatment liquid is supplied. The method according to any one of claims 6 to 8, wherein the treatment liquid is continuously discharged from the treatment liquid discharge port at a second flow rate. The pulp fiber-containing material contains the pulp fiber to be treated derived from used sanitary products and a super absorbent polymer.
In the pulp fiber forming step for a medium, at least a part of the superabsorbent polymer is dissolved in the treatment liquid.
The method according to any one of claims 6 to 9. The method according to claim 10, wherein the treatment liquid is acidic, weakly acidic or neutral. The method according to claim 10 or 11, further comprising an inactivation step of inactivating the superabsorbent polymer with an acid before the pulp fiber-containing material supply step. The method according to claim 12, wherein the acid is an acid capable of forming a complex with a metal ion contained in excrement. The method according to any one of claims 1 to 13, further comprising a cellulase production step of producing cellulase using the pulp fiber for a medium after the pulp fiber formation step for a medium. Pulp fiber for medium as a medium for cellulase-producing bacteria derived from used sanitary products containing pulp fiber.
The pulp fiber for a medium has a hemicellulose content of less than 8.0% by mass.
The pulp fiber for a medium, which is characterized by the above. The pulp fiber for a medium according to claim 15, wherein the pulp fiber for a medium has a lignin content of 0.10% by mass or less. The pulp fiber for a medium according to claim 15 or 16, wherein the pulp fiber for a medium has an ash content of 0.65% by mass or less. The pulp fiber for a medium according to any one of claims 15 to 17, wherein bacteria are not detected in the pulp fiber for a medium by a pour culture method and / or a plate culture method. The use of pulp fibers for a medium as a medium for cellulase-producing bacteria for the production of cellulase.
The pulp fiber for the medium is derived from a used sanitary product containing the pulp fiber.
The pulp fiber for a medium has a hemicellulose content of less than 8.0% by mass.
The above-mentioned use. The use according to claim 19, wherein the pulp fiber for a medium has a lignin content of 0.10% by mass or less.

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