Resin composition derived from used sanitary article containing excrement

Abstract

To provide a resin composition derived from a used sanitary article containing excrement which has improved moldability, workability, flame retardance and sanitation and safety, and is usable for various applications suitable for material recycling and thermal recycling.SOLUTION: A resin composition derived from a used sanitary article containing excrement contains a soluble component and an insoluble component. The ratio of the soluble component is 80 to 90 mass%. The ratio of the insoluble component is 10 to 19 mass%. The ratio of the nitrogen atom contained in the resin composition is less than 0.5 mass%.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resin composition derived from used sanitary products containing excrement.

Background Art

[0002] Resin compositions obtained by recycling sanitary products or resin molded articles using the same are known. For example, Patent Document 1 discloses a pulp-containing resin molded article. The resin molded article contains 19.8 to 50.5% by weight of pulp fibers, 0.2 to 0.5% by weight of a superabsorbent polymer, and 49 to 80% by weight of a thermoplastic resin different from the superabsorbent polymer. The pulp fibers and superabsorbent polymer contained in the resin molded article can be those recovered from the absorbent body of an absorbent article.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The resin molded article of Patent Document 1 is formed using a mixture or its pellets (hereinafter also referred to as "resin composition") in which 19.8 to 50.5% by weight of pulp fibers, 0.2 to 0.5% by weight of a superabsorbent polymer, and 49 to 80% by weight of a thermoplastic resin different from the superabsorbent polymer are mixed. The resin composition contains 20.0% by weight or more in total of pulp fibers and superabsorbent polymer, which are components that do not dissolve in heat and / or are difficult to dissolve in heat (hereinafter also referred to as "insoluble components"). Therefore, when trying to form a resin molded article using the resin composition, there is a risk that the molding and processing become difficult due to the large amount of insoluble components contained.

[0005] Moreover, the insoluble components do not contribute to combustion or tend to have a low calorific value. Therefore, when attempting to form a heat source such as solid fuel using the resin composition, the combustibility may be reduced due to the high content of insoluble components.

[0006] In addition, in the resin molded product of Patent Document 1, when using the pulp fibers and superabsorbent polymers of the absorbent article, they are taken out from the absorbent articles generated as production losses. Therefore, the absorbent articles are unused and do not contain excrement. Therefore, in the resin composition containing pulp fibers and superabsorbent polymers, no consideration is given to impurities derived from excrement (including Escherichia coli, etc.).

[0007] However, in reality, the amount of absorbent articles generated as production losses is extremely small compared to the amount of used absorbent articles that have been used and contain excrement. Therefore, from the perspective of reducing environmental impact, it is important to recycle materials derived from used absorbent articles containing excrement. In that case, in order to make the resin composition derived from used absorbent articles containing excrement a more hygienic, safe and secure material, it is necessary to keep the content of impurities derived from excrement low.

[0008] Thus, there is room for improvement in the resin composition derived from used sanitary products (including absorbent articles) containing excrement, at least in terms of moldability, processability, combustibility, and hygiene and safety aspects.

[0009] An object of the present invention is to provide a resin composition that can be used for various applications suitable for material recycling and thermal recycling, in which the moldability, processability, combustibility, and hygiene and safety aspects are improved in the resin composition derived from used sanitary products containing excrement.

Means for Solving the Problems

[0010] One aspect of the present invention is a resin composition derived from used sanitary products containing excrement, comprising a soluble component and an insoluble component, wherein the proportion of the soluble component is 80 to 90% by mass, the proportion of the insoluble component is 10 to 19% by mass, and the proportion of nitrogen atoms contained in the resin composition is less than 0.5% by mass.

[0011] Another aspect of the present invention is a sound-absorbing material comprising the resin composition described in the above aspect.

[0012] Still another aspect of the present invention is a solid fuel comprising the resin composition described in the above aspect and having a bulk specific gravity of 0.3 to 0.5.

[0013] Still another aspect of the present invention is a container comprising the resin composition described in the above aspect.

Advantages of the Invention

[0014] According to the present invention, in a resin composition derived from used sanitary products containing excrement, a resin composition suitable for various applications suitable for material recycling and thermal recycling, with improved moldability, processability, combustibility, hygiene, and safety, can be provided.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0016] This embodiment relates to the following aspects. [Aspect 1] A resin composition derived from used sanitary products containing excrement, comprising a soluble component and an insoluble component, wherein the proportion of the soluble component is 80 to 90% by mass, the proportion of the insoluble component is 10 to 19% by mass, and the proportion of nitrogen atoms contained in the resin composition is less than 0.5% by mass.

[0017] In this resin composition, the proportion of the soluble component, which has a large calorific value and is easily soluble, and thus has high moldability, processability, and combustibility, is 80% by mass or more, and the proportion of the insoluble component, which has a small calorific value and is difficult to dissolve, and thus has low moldability, processability, and combustibility, is 19% by mass or less. Therefore, this resin composition is excellent in moldability, processability, and combustibility. Also, in this resin composition, the proportion of the insoluble component with low moldability and processability is 10% by mass or more and is present in a small amount. Thereby, the stability of the product shape after molding and processing this resin composition can be enhanced, and the safety is improved. Furthermore, in this resin composition, the proportion of nitrogen atoms derived from excrement is less than 0.5% by mass, so the impurities derived from excrement are extremely few. Therefore, this resin composition is a material excellent in hygiene and safety. Thus, this resin composition is a material excellent in moldability, processability, and combustibility, and also excellent in hygiene and safety, and therefore is suitable for material recycling and thermal recycling.

[0018] [Aspect 2] The resin composition according to Aspect 1, wherein the soluble component contains polyolefin as a main component. This resin composition contains polyolefin, which has a large calorific value and a low melting point, as the main component of the soluble component. Therefore, this resin composition is more excellent in moldability, processability, and combustibility. However, "main component" means occupying 50% by mass or more of the soluble component.

[0019] [Aspect 3] The resin composition according to Aspect 2, wherein the soluble component further contains a polyester resin. This resin composition further contains a polyester resin that is difficult to mix with polyolefin as a soluble component. Therefore, in this resin composition, an air layer is likely to be formed between the polyolefin and the resin composition. As a result, this resin composition is not only more excellent in flammability but also excellent in heat insulation and sound insulation as other applications. The polyester resin is used, for example, as a fiber for the surface sheet in absorbent articles for sanitary products.

[0020] [Aspect 4] The resin composition according to Aspect 3, wherein the polyester resin contains polyethylene terephthalate. This resin composition further contains polyethylene terephthalate that is difficult to mix with polyolefin as a soluble component. Therefore, in this resin composition, an air layer is likely to be formed between the polyolefin and the resin composition. As a result, this resin composition is not only more excellent in flammability but also excellent in heat insulation and sound insulation as other applications.

[0021] [Aspect 5] The resin composition according to Aspect 2, wherein the soluble component further contains at least one of polyurethane and a styrene-containing polymer. In this resin composition, as a soluble component, it further contains at least one of polyurethane and a styrene-containing polymer that is difficult to mix with polyolefin. Therefore, in this resin composition, an air layer is likely to be formed between at least one of polyurethane and a styrene-containing polymer and the polyolefin. As a result, this resin composition is not only more excellent in flammability but also excellent in heat insulation and sound insulation as other applications. The polyurethane and the styrene-containing polymer are used, for example, as elastic members or adhesives in absorbent articles for sanitary products.

[0022] [Aspect 6] The resin composition according to Aspect 1 or 2, wherein the insoluble component contains at least one of cellulose-based fibers, superabsorbent polymers, and inorganic compounds. In this resin composition, as an insoluble component, it contains at least one of pulp fibers, superabsorbent polymers, and inorganic compounds that are difficult to mix with the soluble component. Therefore, in this resin composition, an air layer is likely to be formed between at least one of the pulp fibers, superabsorbent polymers, and inorganic compounds and the soluble component. Thereby, this resin composition is not only more excellent in flammability but also excellent in heat insulation and sound insulation as other applications.

[0023] [Aspect 7] The resin composition according to Aspect 1 or 2, wherein the proportion of ash contained in the resin composition is less than 4% by mass. In this resin composition, the proportion of ash that does not contribute to heat generation and has low moldability, processability, and flammability is less than 4% by mass. Therefore, this resin composition is excellent in moldability, processability, and flammability.

[0024] [Aspect 8] The resin composition according to Aspect 1 or 2, wherein the proportion of chlorine atoms contained in the resin composition is less than 0.1% by mass. In this resin composition, the proportion of chlorine atoms that pose a problem in terms of safety when processed or reused is less than 0.1% by mass. Therefore, this resin composition is excellent in safety and peace of mind.

[0025] [Aspect 9] The resin composition according to Aspect 1 or 2, wherein Escherichia coli contained in the resin composition is below the detection limit. In this resin composition, Escherichia coli derived from excrement that poses a problem in terms of hygiene when processed or reused is below the detection limit. That is, since the impurities derived from excrement are extremely small, this resin composition is more excellent in terms of hygiene and safety.

[0026] [Aspect 10] The resin composition according to Aspect 1 or 2, wherein the proportion of sulfur atoms contained in the resin composition is less than 0.1% by mass. In this resin composition, the proportion of sulfur atoms derived from excrement, which causes problems in terms of hygiene when processed or reused, is less than 0.1% by mass. That is, since the impurities derived from excrement are extremely few, this resin composition is superior in terms of hygiene and safety.

[0027] [Aspect 11] A sound-absorbing material containing the resin composition according to Aspect 1 or 2. This sound-absorbing material is formed using a resin composition containing 80 to 90% by mass of a melting component with high formability and processability and 10 to 19% by mass of an insoluble component with low formability and difficulty in mixing with the melting component. Therefore, in this sound-absorbing material, an air layer is easily formed between the melting component and the insoluble component. Therefore, while being formed into a desired shape, this sound-absorbing material is excellent in heat insulation and sound insulation. Furthermore, in the resin composition contained in this sound-absorbing material, the proportion of nitrogen derived from excrement is less than 0.5% by mass, so the impurities derived from excrement are extremely few. Therefore, this sound-absorbing material is hygienic and excellent in safety.

[0028] [Aspect 12] A solid fuel containing the resin composition according to Aspect 1 or 2 and having a bulk specific gravity of 0.3 to 0.5. This solid fuel is formed using a resin composition containing 80% by mass or more of a melting component with a large calorific value and high combustibility and containing no more than 19% by mass of an insoluble component with a small calorific value and low combustibility, and has a bulk specific gravity of 0.3 to 0.5. Therefore, this solid fuel is extremely excellent in calorific value and combustibility.

[0029] [Aspect 13] A container containing the resin composition according to Aspect 1 or 2. This container is formed using a fat composition that contains 80% by mass or more of a melt component with high formability and processability and only 19% by mass or less of an insoluble component with low formability and processability, and is excellent in formability and processability. Therefore, this container is easily formed into a desired shape. Furthermore, this container is formed using a resin composition in which the proportion of nitrogen derived from excrement is less than 0.5% by mass and the impurities derived from excrement are extremely small. Therefore, this container is hygienic and excellent in safety. Examples of the container include molded articles formed using a resin composition such as plastic bags, trash cans, pallets, buckets, and simple toilets.

[0030] Hereinafter, the resin composition derived from used sanitary products containing excrement according to this embodiment will be described.

[0031] A used sanitary product containing excrement is a sanitary product that has been used to absorb excrement (examples: urine, feces, blood). However, when a used sanitary product containing excrement is discarded and is grouped with used sanitary products that do not contain excrement and is treated as a used sanitary product containing excrement as a whole, the used sanitary product containing excrement may include used sanitary products that do not contain excrement. Here, used sanitary products that do not contain excrement include sanitary products that have been used but have not absorbed excrement, unused sanitary products, and sanitary products such as production losses. Examples of sanitary products include disposable diapers, urine pads, incontinence pads, sanitary napkins, disposable underwear, bed sheets, and pet sheets.

[0032] This resin composition is a resin composition composed of substances derived from used sanitary products containing excrement, and includes a soluble component and an insoluble component. The soluble component is a component that dissolves in heat and / or a component that easily dissolves in heat. On the other hand, the insoluble component is a component that does not dissolve in heat and / or a component that is difficult to dissolve in heat. Here, "dissolving / non-dissolving in heat" and "easily dissolving / difficult to dissolve in heat" mean dissolving / non-dissolving and easily dissolving / difficult to dissolve by heating, and the heating temperature is set to 280 °C. In other words, a component with a melting point of 280 °C or lower is used as the soluble component, and a component with a melting point exceeding 280 °C or a component that decomposes thermally without melting is used as the insoluble component. Note that these components exclude metals.

[0033] As the soluble component, there is no particular limitation as long as it is commonly used as a constituent member of sanitary products and satisfies the conditions of the above soluble component. Examples of the soluble component include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins such as 6-nylon and 6,6-nylon, polyurethane resins such as urethane rubber, and styrene-containing polymers such as styrene-butadiene and styrene-ethylene-butadiene-styrene.

[0034] As the insoluble component, there is no particular limitation as long as it is commonly used as a constituent member of sanitary products and satisfies the conditions of the above soluble component. Examples of the insoluble component include cellulose fibers, superabsorbent polymers, and inorganic substances.

[0035] Examples of the cellulose fiber include natural cellulose fibers, regenerated cellulose fibers such as rayon, purified cellulose fibers such as lyocell, and semi-synthetic cellulose fibers such as acetate fiber. Examples of the natural cellulose fibers include pulp fibers such as wood pulp fibers and non-wood pulp fibers, and cotton fibers. Examples of the wood pulp fibers include softwood pulp fibers and hardwood pulp fibers. Examples of the non-wood pulp fibers include straw pulp fibers, bagasse pulp fibers, rush pulp fibers, kenaf pulp fibers, ramie pulp fibers, bamboo pulp fibers, hemp pulp fibers, and cotton pulp fibers. Examples of the cotton fibers include Gossypium hirsutum cotton fibers, Gossypium barbadense cotton fibers, Gossypium arboreum cotton fibers, and Gossypium herbaceum cotton fibers. The cotton fibers may be organic cotton fibers or pre-organic cotton (trademark) fibers. The organic cotton fibers mean cotton certified by GOTS (Global Organic Textile Standard).

[0036] Examples of the superabsorbent polymer include starch-based, cellulose-based, and synthetic polymer-based polymer absorbents. Examples of the starch-based or cellulose-based superabsorbent polymer include starch-acrylic acid (salt) graft copolymers, saponified products of starch-acrylonitrile copolymers, and crosslinked products of sodium carboxymethyl cellulose. Examples of the synthetic polymer-based superabsorbent polymer include polyacrylate-based, polysulfonate-based, maleic anhydride-based, polyacrylamide-based, polyvinyl alcohol-based, polyethylene oxide-based, polyaspartate-based, polyglutamate-based, and polyalginate-based polymers, etc.

[0037] Examples of the inorganic substance include calcium carbonate, barium sulfate, calcium sulfate, barium carbonate, zinc oxide, magnesium oxide, titanium oxide, talc, silica, clay, kaolin, alumina, and mica.

[0038] In this resin composition, the proportion of the soluble component is 80 to 90% by mass. Thus, in this resin composition, the proportion of the soluble component, which has a large calorific value and is easily soluble, that is, has high moldability, processability, and combustibility, is 80% by mass or more, which is very high. Thereby, the moldability, processability, and combustibility of this resin composition can be enhanced. Therefore, this resin composition can be suitably used for applications that require a large calorific value or applications that require moldability and processability. The upper limit of 90% by mass is determined in relation to the proportion of other components, for example, the insoluble component.

[0039] On the other hand, the proportion of the insoluble component is 10 to 19% by mass. Thus, in this resin composition, the proportion of the insoluble component, which has a small calorific value and is difficult to dissolve, that is, has low moldability, processability, and combustibility, is 10% by mass or more, and although it is small, it exists. Thereby, the shape stability of the product after molding and processing this resin composition can be enhanced, and the safety during use is also increased. The upper limit of 90% by mass is determined in relation to the proportion of the insoluble component. The upper limit of 19% by mass is determined in relation to the proportion of other components, for example, the soluble component.

[0040] Since this resin composition is composed of substances derived from used sanitary products containing excrement, it may contain organic substances (nitrogen compounds) having nitrogen atoms that are present in excrement. However, in this resin composition, the proportion of nitrogen atoms is suppressed to less than 0.5% by mass. Thus, in this resin composition, the proportion of nitrogen atoms derived from organic substances in excrement can be extremely reduced, so the hygiene and safety of this resin composition can be enhanced.

[0041] Thus, this resin composition is a material that is excellent in moldability, processability, and combustibility, and is also excellent in terms of hygiene and safety. Therefore, it is suitable for material recycling and thermal recycling.

[0042] Next, a configuration example of a sanitary product (absorbent article) will be described. The sanitary product includes a top sheet, a back sheet, and an absorber disposed between the top sheet and the back sheet. Examples of the size of the sanitary product include, but are not limited to, a length of about 15 to 100 cm and a width of 5 to 100 cm. Note that the sanitary product may further include other members provided in general sanitary products, such as a diffusion sheet, a leak-proof wall, a side sheet, an outer package sheet, and a filamentous or sheet-like elastic member disposed on the leak-proof wall or the outer package sheet.

[0043] Examples of the constituent members of the surface sheet include a liquid-permeable nonwoven fabric, a synthetic resin film having liquid-permeable pores, and composite sheets thereof. Examples of the constituent members of the back sheet include a liquid-impermeable nonwoven fabric, a liquid-impermeable synthetic resin film, and composite sheets thereof. Examples of the constituent members of the diffusion sheet include a liquid-permeable nonwoven fabric. Examples of the constituent members of the leak-proof wall and side sheets include a water-repellent nonwoven fabric. Examples of the constituent members of the outer sheet include a liquid-impermeable and breathable nonwoven fabric, a liquid-impermeable and breathable synthetic resin film, and composite sheets thereof. Examples of the constituent members of the elastic member include rubber-based synthetic resins. There is no particular limitation on the type of nonwoven fabric, and examples include meltblown nonwoven fabric, spunbond nonwoven fabric, airlaid nonwoven fabric, air-through nonwoven fabric, etc. There is no particular limitation on the type of synthetic resin film, and known film materials can be used. There is no particular limitation on the material of the nonwoven fabric or synthetic resin film as long as it can be used for sanitary products. Examples include olefin resins such as polyethylene and polypropylene, polyamide resins such as 6-nylon and 6,6-nylon, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, etc. Cellulosic fibers may be used as the material of the nonwoven fabric. In order to impart breathability, the synthetic resin film may contain inorganic particles such as calcium carbonate. There is no particular limitation on the material of the rubber-based synthetic resin as long as it can be used for sanitary products. Examples include styrene-butadiene rubber and urethane rubber. These materials of nonwoven fabrics and synthetic resin films are synthetic resins and can be referred to as plastic materials.

[0044] As a constituent member of the absorber, at least one of an absorber material such as a cellulose-based fiber and a superabsorbent polymer can be mentioned. Examples of the cellulose-based fiber include natural cellulose fibers such as pulp fibers like wood pulp fibers, crosslinked pulp fibers, and non-wood pulp fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers. In the case of pulp fibers, as their size, the average major axis of the fibers is, for example, several tens of μm, preferably 20 to 40 μm, and the average fiber length is, for example, several mm, preferably 2 to 5 mm. Examples of the superabsorbent polymer (Super Absorbent Polymer: SAP) include water-absorbing polymers such as polyacrylate-based, polysulfonate-based, and maleic anhydride-based polymers. As the size (when dry) of the superabsorbent polymer, the average particle diameter is, for example, several hundreds of μm, preferably 200 to 500 μm. The absorber may include a core wrap formed of a liquid-permeable sheet.

[0045] One surface and the other surface of the absorber are each joined to the surface sheet and the back sheet via an adhesive. In plan view, the portion (peripheral portion) of the surface sheet that extends outside the absorber so as to surround the absorber is joined to the portion (peripheral portion) of the back sheet that extends outside the absorber so as to surround the absorber via an adhesive. Therefore, the absorber is wrapped inside the joined body of the surface sheet and the back sheet. The adhesive is not particularly limited, and examples thereof include hot melt adhesives. Examples of the hot melt adhesive include pressure-sensitive adhesives or heat-sensitive adhesives mainly composed of rubber such as styrene-ethylene-butadiene-styrene, styrene-butadiene-styrene, styrene-isoprene-styrene, and polyurethane, or mainly composed of polyolefins such as polyethylene.

[0046] In this embodiment, as a preferred aspect, the melting component contains a polyolefin resin as a main component. However, the main component means that the proportion in the melting component is 50% by mass or more. The polyolefin resin means a polymer containing olefins (for example, ethylene, propylene, butylene, etc.), diolefins (for example, butadiene, isoprene, etc.) as constituent elements. Examples of the polyolefin resin include polyethylene and polypropylene. Thus, in this resin composition, a large amount of polyolefin resin with a large calorific value and a low melting point is contained in the melting component. Thereby, this resin composition is more excellent in moldability, processability, and combustibility.

[0047] The proportion of the polyolefin resin in the melting component is preferably 60% by mass, more preferably 70% by mass from the viewpoints of moldability, processability, and combustibility as the lower limit. There is no particular limitation as the upper limit. However, when it is preferable to contain other resins depending on the use of this resin composition (for example, a member for heat insulation or a member for sound insulation), for example, 85% by mass can be mentioned.

[0048] In this embodiment, as a preferred aspect, the melting component further contains a polyester resin. However, examples of the polyester resin include polyethylene terephthalate and polybutylene terephthalate. Thus, in this resin composition, since a polyester resin that is difficult to mix with the polyolefin resin is further contained in the melting component, an air layer is easily formed between the polyester resin and the polyolefin resin. Thereby, this resin composition is not only more excellent in combustibility but also excellent in heat insulation and sound insulation as other uses.

[0049] The proportion of the polyester resin in the melting component is preferably 3% by mass, more preferably 6% by mass from the viewpoints of heat insulation and sound insulation as the lower limit. The upper limit is preferably 15% by mass, more preferably 12% by mass from the viewpoints of moldability and processability.

[0050] In the present embodiment, as a preferred aspect, the soluble component further contains at least one of a polyurethane-based resin and a styrene-containing polymer. However, examples of the polyurethane-based resin include polyurethane, and examples of the styrene-containing polymer include styrene-ethylene-butadiene-styrene, styrene-butadiene-styrene, and styrene-isoprene-styrene. Thus, in this resin composition, since at least one of the polyurethane-based resin and the styrene-containing polymer, which are difficult to mix with the polyolefin-based resin, is further contained in the soluble component, an air layer is likely to be formed between at least one of the polyurethane-based resin and the styrene-containing polymer and the polyolefin-based resin. Thereby, this resin composition is not only more excellent in flammability but also excellent in heat insulation and sound insulation as other applications.

[0051] The proportion of at least one of the polyurethane-based resin and the styrene-containing polymer in the soluble component is preferably 3% by mass, more preferably 6% by mass, from the viewpoint of heat insulation and sound insulation as the lower limit. The upper limit is preferably 15% by mass, more preferably 12% by mass, from the viewpoint of moldability and processability.

[0052] In the present embodiment, as a preferred aspect, the insoluble component contains at least one of a cellulose-based fiber, a superabsorbent polymer, and an inorganic compound. However, examples of the cellulose-based fiber include pulp fiber. Examples of the superabsorbent polymer include polyacrylate-based, polysulfonate-based, and maleic anhydride-based superabsorbent polymers. Examples of the inorganic compound include calcium carbonate, zinc oxide, magnesium oxide, and alumina. Thus, in this resin composition, since at least one of the pulp fiber, the superabsorbent polymer, and the inorganic compound, which are difficult to mix with the soluble component, is contained in the insoluble component, an air layer is likely to be formed between at least one of the pulp fiber, the superabsorbent polymer, and the inorganic compound and the soluble component. Thereby, this resin composition is not only more excellent in flammability but also excellent in heat insulation and sound insulation as other applications.

[0053] The proportion of at least one of pulp fibers, superabsorbent polymers, and inorganic compounds in the insoluble components is, from the viewpoint of heat insulation and sound insulation, preferably 80% by mass or more, more preferably 90% by mass or more, as the lower limit. There is no particular upper limit.

[0054] In a preferred embodiment of the present embodiment, the proportion of ash contained in the resin composition is less than 4% by mass. Thus, in this resin composition, the proportion of ash, which does not contribute to heat generation and has low moldability, processability, and flammability, is only less than 4% by mass. Therefore, this resin composition is excellent in moldability, processability, and flammability.

[0055] In a preferred embodiment of the present embodiment, the proportion of chlorine atoms contained in the resin composition is less than 0.1% by mass. Thus, in this resin composition, the proportion of chlorine atoms, which pose a problem in terms of safety during processing or reuse, is only less than 0.1% by mass. Therefore, this resin composition is excellent in safety.

[0056] Since this resin composition is composed of substances derived from used sanitary products containing excrement, it may contain Escherichia coli present in excrement. However, in a preferred embodiment of the present embodiment, the Escherichia coli contained in the resin composition is below the detection limit. Thus, in this resin composition, Escherichia coli derived from excrement, which poses a problem in terms of hygiene during processing or reuse, is below the detection limit. That is, since the impurities derived from excrement are extremely small, this resin composition is more excellent in terms of hygiene and safety.

[0057] Since this resin composition is composed of substances derived from used sanitary products containing excrement, it may contain organic substances (sulfur compounds) having sulfur atoms present in excrement. However, in a preferred embodiment of the present embodiment, the proportion of sulfur atoms in this resin composition is suppressed to less than 0.1% by mass. Thus, in this resin composition, the proportion of sulfur atoms derived from excrement, which poses a problem in terms of hygiene during processing or reuse, can be made extremely small, so the hygiene and safety of this resin composition can be enhanced.

[0058] Next, a sound-absorbing material containing the resin composition according to this embodiment will be described. For this sound-absorbing material, the resin composition itself described above can be used. However, when using it, the resin composition is held in a predetermined region to form a desired shape as a whole. For example, the resin composition is packed into a resin container, that is, held in the region inside the container to form a plate-shaped sound-absorbing material. If necessary, a required number of containers (sound-absorbing members) packed with the resin composition can be arranged or laminated for use. Examples of the container packed with the resin composition include a bag made of a polyolefin resin having a size of (400 to 600 mm) × (400 to 600 mm) × (20 to 100 mm). By packing 1 to 5 kg of the resin composition into the bag, a predetermined plate-shaped sound-absorbing material can be obtained. Alternatively, for example, the resin composition is packed between two walls, that is, held in the region between the two walls to form a wall-shaped sound-absorbing material.

[0059] This sound-absorbing material is formed using a resin composition containing 80 to 90% by mass of a dissolution component with high moldability and processability, and 10 to 19% by mass of an insoluble component with low moldability and processability that is difficult to mix with the dissolution component. Therefore, in this sound-absorbing material, an air layer is easily formed between the dissolution component and the insoluble component. Therefore, while being formed into a desired form, this sound-absorbing material is excellent in heat insulation and sound insulation. Furthermore, in the resin composition contained in this sound-absorbing material, the ratio of nitrogen derived from excrement is less than 0.5% by mass, so the impurities derived from excrement are extremely few. Therefore, this sound-absorbing material is hygienic and excellent in safety and reliability.

[0060] Since the above sound-absorbing material is excellent not only in sound insulation but also in heat insulation, it can also be used as a heat insulating material. The configuration as the heat insulating material can also be the same as the configuration as the above sound-absorbing material. Thereby, this heat insulating material is excellent in heat insulation and sound insulation, and is hygienic and excellent in safety and reliability.

[0061] Next, a solid fuel containing the resin composition according to this embodiment will be described. This solid fuel is formed by extrusion molding using the resin composition described above. The pressure and temperature of the extrusion molding are not particularly limited as long as the solid fuel can be formed. Examples of the pressure include 5 to 50 kg / cm 2 and examples of the temperature include 100 to 200°C. And the bulk specific gravity of the solid fuel is preferably 0.3 to 0.5. If the bulk specific gravity is too small, there is a risk that the calorific value will decrease too much, and if the bulk specific gravity is too large, there is a risk that the firepower will become too strong.

[0062] This solid fuel is formed using a resin composition that contains 80% by mass or more of a dissolving component with a large calorific value and high combustibility and contains no more than 19% by mass of an undissolved component with a small calorific value and low combustibility, and has a bulk specific gravity of 0.3 to 0.5. Therefore, this solid fuel is extremely excellent in calorific value and combustibility.

[0063] Next, a container containing the resin composition according to this embodiment will be described. Examples of this container include molded products formed using the resin composition such as plastic bags, trash cans, pallets, buckets, and portable toilets. The plastic bag is formed, for example, by the inflation method or the die method using the resin composition described above. The other molded products are formed, for example, by extrusion molding using the resin composition described above.

[0064] This container is formed using a resin composition that contains 80% by mass or more of a dissolving component with high moldability and processability and contains no more than 19% by mass of an undissolved component with low moldability and processability, and is excellent in moldability and processability. Therefore, this container is easily formed into a desired shape. Furthermore, this container is formed using a resin composition in which the proportion of nitrogen derived from excrement is less than 0.5% by mass and the impurities derived from excrement are extremely small. Therefore, this container is hygienic and excellent in safety and reliability.

[0065] Next, a method for manufacturing a resin composition derived from a used sanitary product containing excrement according to the present embodiment will be specifically described. In the present embodiment, as an example of the sanitary product, a disposable diaper will be taken for explanation.

[0066] FIG. 1 is a flowchart showing a method for manufacturing a resin composition derived from a used sanitary product containing excrement according to the present embodiment. This method includes a first separation step S2, a second separation step S3, and a washing step S5. The plastic material produced as a result can be used as the resin composition. In the present embodiment, this method further includes a crushing step S1, a pneumatic conveying step S4, and a squeezing, dewatering, and drying step S6. Thereby, the impurities in the produced plastic material can be reduced. In the present embodiment, this method further includes a dust removal step S7, a SAP separation step S8, an oxidant treatment step S9, a pulp fiber separation step S10, and a mixing step S11. Thereby, by adding the pulp fibers and the superabsorbent polymer separated in the SAP separation step S8 and the pulp fiber separation step S10 to the above-mentioned plastic material in the mixing step S11, a resin composition with an even more adjusted proportion of insoluble components can be formed. This will be specifically described below.

[0067] In the present embodiment, used sanitary products are collected from the outside for reuse (recycling) and used. At that time, by enclosing a plurality of used sanitary products in a collection bag, leakage of excrement, fungi, and odors to the outside is suppressed. Each used sanitary product in the collection bag is collected in a rolled or folded state with the surface sheet on which excrement is excreted facing inward so that, for example, excrement and fungi are not exposed on the front side and odors do not diffuse to the surroundings. Note that the used sanitary products do not necessarily need to be enclosed in a collection bag, nor do they necessarily need to be rolled up.

[0068] The crushing step S1 is a step of crushing a used absorbent article together with an inactivating aqueous solution containing an inactivator that inactivates the superabsorbent polymer. The crushing step S1 is carried out by a crushing device such as a twin-shaft crusher. Crushing together with the inactivating aqueous solution includes cases where the used absorbent article is supplied to the crushing device together with the inactivating aqueous solution and crushed, cases where the used absorbent article is put into the inactivating aqueous solution stored in the crushing device and crushed, and combinations thereof. In this embodiment, the used absorbent article is crushed while being supplied to the crushing device together with the inactivating aqueous solution. In this method, when the inactivating aqueous solution is used after the first separation step S2, if the inactivating aqueous solution is insufficient, it is appropriately replenished.

[0069] In this embodiment, a collection bag containing the used absorbent article is supplied to the receiving device and moves to a crushing device communicating with the lower side of the receiving device. At the same time, an inactivating aqueous solution (exemplified: acidic aqueous solution) is supplied to the crushing device via the receiving device. At this time, the inactivating aqueous solution may be supplied so as to fall on the used absorbent article from above the used absorbent article. This is from the viewpoint of suppressing the scattering of crushed materials (including substances derived from excrement such as bacteria and odoriferous substances) during crushing. The collection bag is crushed together with the inactivating aqueous solution by the crushing device. Thereby, the used absorbent article in the collection bag is crushed in the inactivating aqueous solution together with the collection bag, and crushed materials having a size of, for example, 1 to 150 mm are generated. At this time, the superabsorbent polymer is inactivated and dehydrated by the inactivating aqueous solution to become small in particle size. The crushed materials are sent to the first separation step S2 together with the inactivating aqueous solution.

[0070] As the inactivating aqueous solution, it is preferable to use an aqueous solution of an inorganic acid and an organic acid, that is, an acidic aqueous solution. When using an acidic aqueous solution, it is difficult for ash and chlorine to remain in plastic materials, superabsorbent polymers, pulp fibers, etc. compared with the case of using an aqueous solution such as lime or calcium chloride, and the degree of inactivation (particle size and specific gravity) can be easily adjusted by pH. As the organic acid, citric acid having a chelating effect and a cleaning effect is preferable, and as the inorganic acid, sulfuric acid which does not contain chlorine and has a low cost is preferable. Note that as the inactivating aqueous solution, it may be inactivated with an aqueous solution containing a polyvalent metal ion source capable of supplying a known polyvalent metal ion.

[0071] The pH of the acidic aqueous solution is preferably 1.0 to 4.0. When the pH is 1.0 or more, the equipment is hardly corroded, and the alkali chemicals required for the neutralization treatment during the wastewater treatment can also be reduced. When the pH is 4.0 or less, the superabsorbent polymer can be made sufficiently small and the sterilization ability can be enhanced. Since the pH changes depending on the water temperature, the pH in the present invention means the pH measured at an aqueous solution temperature of 20°C. The concentration of the acidic aqueous solution is not particularly limited, but in the case of citric acid, it is preferably 0.5 to 4% by mass, and in the case of sulfuric acid, it is preferably 0.1 to 2.0% by mass.

[0072] At the time of the crushing step S1, due to the heat generated during crushing and / or the heat of the acidic aqueous solution, etc., the bonding strength of the adhesive (for example, hot melt adhesive) between the respective constituent members can be reduced, and the respective constituent members can be easily separated from each other. Alternatively, by heating the acidic aqueous solution (temperature: 70 to 95°C), the adhesive (for example, hot melt adhesive) used for bonding between the constituent members of the used absorbent article can be softened, and the bonding strength of the adhesive can be reduced. Thereby, the constituent members can be easily separated from each other naturally or by a small impact. It is also possible to further sterilize (disinfect) the used absorbent article.

[0073] Next, in the first separation step S2, a mixture of the plastic material, the inactivated superabsorbent polymer, the pulp fiber, the excrement, and the inactivated aqueous solution supplied from the crushing step S1 is separated into a first fraction containing the plastic material and a second fraction containing the inactivated superabsorbent polymer, the pulp fiber, the excrement, and the inactivated aqueous solution. The first separation step S2 is carried out by a separation device such as a screen separator, a pulper separator, or a combination thereof.

[0074] In this embodiment, in the pulper separator, while the acidic aqueous solution containing the crushed material generated in the crushing step S1 is being stored and stirred, the crushed material is dissociated into constituent materials. Then, the acidic aqueous solution containing the crushed material (dissociated constituent materials) is separated by a screen, and the second fraction containing the inactivated superabsorbent polymer, the pulp fiber, the excrement, and the acidic aqueous solution becomes the accept and is sent to the dust removal step S3. On the other hand, the first fraction such as the collection bag, the film, and the non-woven fabric becomes the reject and is sent to the second separation step S4. The separated collection bag, film, non-woven fabric, etc. can be referred to as a plastic material. Note that in the first separation step S2, another acidic aqueous solution not used in the crushing step S1 may be supplied as the acidic aqueous solution. At this time, a part of the pulp fiber, the superabsorbent polymer, and the excrement may not pass through the screen and may remain on the screen together with the first fraction. On the other hand, a part of the collection bag, the film, and the non-woven fabric may pass through the screen together with the second fraction.

[0075] Note that when, as in this embodiment, the superabsorbent polymer is inactivated in advance (in the crushing step S1 or the like), granulated, and the water absorption capacity is suppressed before the first separation step S2, after the first separation step S2, instead of using the inactivated aqueous solution (acidic aqueous solution), after substantially removing the inactivated aqueous solution, water (aqueous solution) not containing the inactivating agent may be used. In that case, water (aqueous solution) not containing the inactivating agent may be used from any step after the first separation step S2. Thereby, the amount of use of the inactivated aqueous solution (and the inactivating agent) can be reduced, and the burden of wastewater treatment can be reduced.

[0076] In this embodiment, in the first separation step S2, the pH of the acidic aqueous solution may be adjusted so as to be maintained within a predetermined range. The predetermined range of the pH means that the variation in pH is within the range of ±1.0. Thereby, the difference between the specific gravity and size of the superabsorbent polymer and the specific gravity and size of the pulp fiber can be made to be within a predetermined range. In this case, the difference being within a predetermined range means, for example, that one is within the range of 0.2 to 5 times that of the other. Thereby, the difference between the pulp fiber and the superabsorbent polymer is such that the specific gravity is within a predetermined range and the size is within a predetermined range. As a result, the pulp fiber and the superabsorbent polymer can be easily separated from other materials (mainly plastic materials) excluding the pulp fiber and the superabsorbent polymer among the materials of the used absorbent article, by utilizing the differences in size and specific gravity. The adjustment of the pH can be performed using an acidic aqueous solution or an alkaline aqueous solution from a pH adjustment device installed in the separation device, based on the value of the pH measured by a pH sensor installed in the separation device. Note that the pH may be similarly adjusted in at least one of the dust removal step S3, the second separation step S4, and the third separation step S5 described later.

[0077] The second separation step S3 is a step of separating the first fraction by applying a physical impact into a plastic material, pulp fibers that remained in the first fraction without being completely separated in the first separation step S2, superabsorbent polymers, and excrement. That is, in the second separation step S3, the plastic material and the mixture of the remaining pulp fibers, superabsorbent polymers, and excrement are separated from the mixture of the plastic material and the remaining pulp fibers, superabsorbent polymers, and excrement. Thereby, the plastic material is recovered.

[0078] In this embodiment, in the second separation step S3, the first fraction is treated with an acidic aqueous solution while applying a physical impact to the first fraction to perform separation. Specifically, first, in the second separation step S3, a mixture (plastic material and residue) in which pulp fibers, a superabsorbent polymer, excrement, and an acidic aqueous solution are separated in the first separation step S2 is supplied to a separation device. The separation device includes a cylindrical portion installed horizontally, a plurality of impellers provided inside the cylindrical portion, a plurality of acidic aqueous solution supply portions provided on the outer peripheral surface on the upper side of the horizontally placed cylindrical portion, and a screen (sieve) provided on the outer peripheral surface on the lower side of the cylindrical portion. There is a supply port for the mixture at one end side of the cylindrical portion and a discharge port at the other end side. The plurality of impellers are arranged at intervals along the central axis direction of the cylindrical portion such that their rotation axes overlap with the central axis of the cylindrical portion. The plurality of impellers are adjusted in the direction of the blades so as to generate an air flow from one end side to the other end side of the cylindrical portion while rotating around the central axis of the cylindrical portion. The plurality of acidic aqueous solution supply portions are arranged at intervals along the central axis direction and inject a new acidic aqueous solution downward into the cylindrical portion. The acidic aqueous solution supply portion preferably injects the acidic aqueous solution in a spray form. The size of each opening of the screen (sieve) is such that pulp fibers and a superabsorbent polymer (, excrement, acidic aqueous solution) can pass through, and it is difficult for the plastic material to pass through.

[0079] The mixture is sprayed with an acidic aqueous solution from each of the plurality of acidic aqueous solution supply portions in the air inside the cylindrical portion of the separation device, stirred by the blades of the rotating impellers, and physically impacted by the collision of the impeller blades, while moving (flowing) from one end side to the other end side of the cylindrical portion. During that time, the mixture is washed away from dirt by the sprayed acidic aqueous solution and / or sterilized and bleached. At the same time, pulp fibers and the like in the mixture are removed from the plastic material in the mixture by physical impact and the like, and the superabsorbent polymer in the mixture is further inactivated by the acidic aqueous solution and removed from the plastic material in the mixture by physical impact and the like. The removed pulp fibers and superabsorbent polymer pass through the screen on the lower side of the cylindrical portion and are separated (removed) together with the acidic aqueous solution.

[0080] On the other hand, the plastic material in the mixture from which pulp fibers, superabsorbent polymers, etc. have been removed is discharged from the discharge port on the other end side of the cylindrical part without passing through the screen. That is, the superabsorbent polymer and pulp fibers that remained without being separated in the first separation step S2 are removed, and a plastic material with reduced impurities is produced and recovered. However, although the amount is not necessarily large, sulfur compounds, nitrogen compounds, etc. derived from excrement that could not be completely removed in the second separation step S3 may remain in the plastic material. Note that the separated acidic aqueous solution may be reused in the first separation step S2 or the crushing step S1. The acidic aqueous solution is as described above.

[0081] The supply amount of the acidic aqueous solution is not particularly limited as long as it can achieve the desired function. For example, the weight of the acidic aqueous solution relative to the weight of the plastic material may be 5 to 100 times, preferably 10 to 50 times. The supply rate of the acidic aqueous solution is not particularly limited as long as it can achieve the desired function. For example, it may be 50 to 500 cm 3 / min, preferably 80 to 200 cm 3 / min. If the supply amount and supply rate are small, it is difficult to obtain the desired effect, and if they are large, there is a risk of damaging equipment, materials, etc.

[0082] In the second separation step S3, as a preferred embodiment, the acidic aqueous solution is sprayed onto the mixture. Due to the spraying force, the remaining superabsorbent polymer and pulp fibers attached to the plastic material can be washed off. Also, since the acidic aqueous solution becomes finer by spraying, it is easier for the acidic aqueous solution to reach the superabsorbent polymer remaining in the details of the plastic material. Further, compared with the case of immersing the plastic material in the acidic aqueous solution, a fresh acidic aqueous solution can be constantly supplied to the surface of the plastic material, and variations in the effect of the acidic aqueous solution can be suppressed.

[0083] In the second separation step S3, instead of treating the first fraction with an acidic aqueous solution, the first fraction may be separated by applying a physical impact thereto. The mixture is stirred by the blades of a rotating impeller in the air inside the cylindrical portion of the separation device, and while being subjected to a physical impact by the collision of the impeller blades, it moves (flows) from one end side to the other end side of the cylindrical portion. During this time, the dirt on the mixture is knocked off by the physical impact. For example, pulp fibers and superabsorbent polymers in the mixture are removed from the plastic material in the mixture by the physical impact. The removed pulp fibers and superabsorbent polymers pass through the screen on the lower side of the cylindrical portion and are separated (removed).

[0084] Alternatively, in the second separation step S3, instead of the acidic aqueous solution, water or an aqueous solution containing no inactivator (hereinafter also simply referred to as "water") may be sprayed onto the first fraction. The mixture is sprayed with water from each of a plurality of water supply parts that supply water in the air inside the cylindrical portion of the separation device, stirred by the blades of a rotating impeller, and while being subjected to a physical impact by the collision of the impeller blades, it moves (flows) from one end side to the other end side of the cylindrical portion. During this time, the dirt on the mixture is washed away by the sprayed water and the dirt is knocked off by the physical impact. For example, the pulp fibers and superabsorbent polymers in the mixture are removed from the plastic material in the mixture by the flow of water and the physical impact, etc. The removed pulp fibers and superabsorbent polymers pass through the screen on the lower side of the cylindrical portion and are separated (removed) together with the water.

[0085] The air conveyance step S4 (conveyance step) is a step of conveying the plastic material separated in the second separation step S3 to the washing step S5 by air. That is, in the air conveyance step S4, the separated plastic material is conveyed to the next step while being dried in the air flow.

[0086] In this embodiment, in the air conveyance step S4, in the pipe connecting the separation device in the second separation step S3 and the cleaning device (described later) in the cleaning step S5, the separated plastic material is conveyed from the separation device to the cleaning device by the air flowing through the pipe by means of a blower. At this time, the moisture contained in the plastic material evaporates or is blown off into the air, so that the moisture content of the plastic material decreases. The moisture content decreases, for example, from about 95% to about 80%. Also, the flow of air can separate a plurality of plastic materials from each other. Thereby, for example, when using a cleaning liquid in the next cleaning step S5, the cleaning liquid can be supplied substantially uniformly to the entire surface of each plastic material. Note that the air conveyance step S4 may not be used, and the separated plastic material may be conveyed by other known conveyance means.

[0087] The cleaning step S5 is a step of injecting a cleaning liquid onto the plastic material separated in the second separation step S3. That is, in the cleaning step S5, sulfur compounds, nitrogen compounds, etc. derived from excrement that could not be completely removed in the second separation step S3 and remain in the plastic material are removed by the cleaning liquid. Furthermore, other impurities such as pulp fibers and superabsorbent polymers that may remain in trace amounts can also be removed by the cleaning liquid.

[0088] In this embodiment, in the cleaning step S5, the plastic material separated in the second separation step S3 (via the air conveyance step S4) is supplied to the cleaning device. The cleaning device includes a conveyor (a screw conveyor in this embodiment) that conveys the plastic material, and a plurality of cleaning liquid supply parts provided above the conveyor that inject the cleaning liquid onto the plastic material being conveyed. The conveyor is inclined upward along the conveyance direction (for example, 30°), whereby the cleaning liquid that is injected and drips from the plastic material is carried to the lower drain opening. The plurality of cleaning liquid supply parts are arranged at intervals along the conveyance direction of the conveyor. The cleaning liquid supply part preferably injects the cleaning liquid in a spray form.

[0089] The plastic material is conveyed from one end to the other end by a conveyor while being sprayed with the cleaning liquid from each of a plurality of cleaning liquid supply units. During that time, the plastic material is sprayed with the cleaning liquid while being physically agitated by screw conveyance. The sulfur compounds, nitrogen compounds, etc. derived from excrement remaining on the plastic material are washed and flushed away by the sprayed cleaning liquid and mixed into the cleaning liquid. That is, the sulfur compounds and nitrogen compounds remaining on the plastic material are removed. Also, when the cleaning liquid has a bactericidal action, the plastic material can be sterilized thereby. When the cleaning liquid is an oxidizing agent, the sulfur compounds, nitrogen compounds, etc. are oxidized and converted into other odorless substances (e.g., sulfur (S) and nitrogen (N2)), which are mixed into the cleaning liquid and / or released as a gas. That is, the sulfur compounds and nitrogen compounds remaining on the plastic material are removed. Also, the plastic material is sterilized by the cleaning liquid.

[0090] In the cleaning step S5, the cleaning liquid is sprayed onto the plastic material. Due to the spraying force, sulfur compounds, nitrogen compounds, and other impurities adhering to the surface of the plastic material can be washed off. Also, since the cleaning liquid becomes finer by spraying, it is easier for the cleaning liquid to reach the sulfur compounds and nitrogen compounds remaining in the details of the plastic material. Also, compared with the case where the plastic material is immersed in the cleaning liquid, fresh cleaning liquid can always be supplied to the surface of the plastic material, and variations in the effect of the cleaning liquid (e.g., the effects of cleaning and sterilization) can be suppressed.

[0091] Here, the cleaning liquid includes, for example, an aqueous oxidizing agent solution containing an oxidizing agent, such as water. The oxidizing agent contains at least one of ozone and hydrogen peroxide. The water includes, depending on the amount of impurities in the plastic material, for example, water at normal temperature and pressure, water or steam at high temperature and / or high pressure, and superheated steam. It may contain a bactericide. In this embodiment, an aqueous oxidizing agent solution is used, and ozone is used as the oxidizing agent from the viewpoints of oxidizing power, bactericidal power, and bleaching power. Specifically, as the aqueous oxidizing agent solution, ozone water in which ozone gas is mixed into water (or an aqueous solution) such as pure water or tap water is used. Note that the aqueous oxidizing agent solution may be acidic from the viewpoint of suppressing the deactivation of ozone. Further, when an acidic aqueous solution such as a (dilute) sulfuric acid aqueous solution is used as the inactivating aqueous solution in at least the second separation step S3 among the crushing step S1, the first separation step S2, and the second separation step S3, it may also be acidic from the viewpoints of the continuity of each step and the effective utilization of the aqueous solution. In that case, a mixture of ozone gas and an acidic aqueous solution (for example, a dilute sulfuric acid aqueous solution) is used. As the acidic aqueous solution, the acidic aqueous solution used in other steps may be reused.

[0092] The ozone concentration in the aqueous oxidizing agent solution is not particularly limited as long as it can achieve the desired function, that is, the oxidizing power, bactericidal power, and bleaching power against sulfur compounds (including sulfuric acid in the acidic aqueous solution), nitrogen compounds, etc. Examples of the concentration include 0.2 to 10 ppm, and 0.5 to 5 ppm is preferable. By the concentration not being too low, the desired function can be exhibited, and by the concentration not being too high, corrosion of the equipment can be suppressed. The treatment time in the aqueous oxidizing agent solution is not particularly limited as long as it can exhibit the desired function, but it is shorter when the ozone concentration in the aqueous oxidizing agent solution is high and longer when the ozone concentration is low, and is typically 1 to 30 minutes. The product of the ozone concentration (ppm) in the aqueous oxidizing agent solution and the treatment time (minutes) of the treatment step (hereinafter, also referred to as "CT value") includes, for example, 0.5 to 200 ppm·min, and 5 to 100 ppm·min is preferable. By the CT value not being too small, the desired function can be exhibited, and by the CT value not being too large, corrosion of the equipment can be suppressed. Note that as the aqueous oxidizing agent solution, the aqueous oxidizing agent solution used in the oxidizing agent treatment step S9 described later may be reused in this step after reducing the concentration.

[0093] Also, the supply amount of the aqueous oxidizing agent solution is not particularly limited as long as it can achieve the desired function. For example, the weight of the aqueous oxidizing agent solution relative to the weight of the plastic material is 5 to 100 times, preferably 10 to 50 times. The supply rate of the aqueous oxidizing agent solution is not particularly limited as long as it can achieve the desired function. For example, it is 50 to 500 cm 3 / min, preferably 80 to 200 cm 3 / min. If the supply amount and supply rate are small, it is difficult to obtain the desired effect, and if they are large, there is a risk of damaging equipment, materials, etc.

[0094] Regarding sterilization or disinfection, for example, there are more than 1 billion general bacteria per ml in used disposable diapers, but the acidic aqueous solution up to the second separation step S3 cannot completely sterilize. Therefore, there are a certain number of general bacteria in the plastic material (with a small amount of pulp fibers or superabsorbent polymer attached) separated in the second separation step S3 (example: 3,400 general bacteria per ml). Then, concerns may arise about the adverse effects on the safety of the operator and the spoilage and mold growth of the taken-out plastic material. Also, there is a strong excrement odor presumably caused by general bacteria. However, by performing the cleaning step S5 using the aqueous oxidizing agent solution, the general bacteria in the plastic material can be removed below the detection limit, similar to Escherichia coli, and sulfur compounds and nitrogen compounds can be decomposed to reduce the excrement odor to an almost undetectable level.

[0095] In this embodiment, an aqueous oxidizing agent solution is sprayed onto the plastic material as the cleaning liquid to remove sulfur compounds, nitrogen compounds, etc. derived from excrement remaining on the plastic material. However, this embodiment is not limited thereto. For example, as the cleaning liquid, a heated liquid (example: hot water or steam, superheated steam) may be sprayed onto the plastic material to remove impurities such as sulfur compounds, nitrogen compounds, general bacteria, and Escherichia coli derived from excrement remaining on the plastic material.

[0096] Alternatively, for example, instead of the cleaning liquid, a heated gas (exemplified by high-temperature (high-pressure) air) may be injected onto the plastic material as the cleaning gas. In that case, as the apparatus and the injection method, for example, in the apparatus of the cleaning step S5, a method of using the cleaning gas instead of the cleaning liquid, or a method of exposing the plastic material to the atmosphere of the cleaning gas can be mentioned.

[0097] Also in these cases, impurities such as sulfur compounds, nitrogen compounds, general bacteria, and Escherichia coli in the plastic material can be decomposed and / or peeled off and removed from the plastic material. In these cases, since an aqueous oxidizing agent solution is not used, it is safe and hygienic, and in addition, there is no treatment of wastewater such as an aqueous oxidizing agent solution, and the treatment cost can be suppressed.

[0098] Alternatively, for example, although it also depends on the amount of impurities in the plastic material, it may not be necessary to perform the treatment as in the above-described cleaning step S5. In that case, for example, to the extent of simply washing with water, or without doing anything, impurities such as sulfur compounds, nitrogen compounds, general bacteria, and Escherichia coli derived from excrement remaining in the plastic material may be removed by the treatment by heating and pressurization in the squeezing dehydration drying step S6 described later.

[0099] The squeezing dehydration drying step S6 is a step of squeezing, dehydrating, and drying the plastic material treated in the cleaning step S5. That is, in the squeezing dehydration drying step S6, a plurality of treated plastic materials are gathered, squeezed as a whole to be dehydrated, and heated and dried.

[0100] In this embodiment, in the squeezing dehydration and drying step S6, the plastic material processed in the washing step S5 is supplied to a squeezing dehydration and drying device. The squeezing dehydration and drying device is a device that squeezes a plurality of plastic materials together while heating, squeezes out moisture, and dehydrates and dries them. Examples of the heating temperature include 80 to 160°C. If the temperature is too high, there is a risk that the pulp fibers that may be contained in the plastic material will carbonize, and if the temperature is too low, it will be difficult to obtain the drying effect. The heating time depends on the heating temperature, but for example, it is 5 seconds to 5 minutes, and preferably 10 seconds to 3 minutes. If the time is too long, the drying effect will saturate, and if the time is too short, it will be difficult to obtain the drying effect. Examples of the pressure for squeezing include 0.2 to 4 MPa, and preferably 0.4 to 2 MPa, although it also depends on the heating temperature and heating time. If the pressure is too low, it is difficult to obtain the dehydration effect, and if the pressure is too high, the dehydration effect will saturate. The squeezing dehydration and drying device softens (and / or melts) the plastic material and extrudes it to the outside through a large number of holes (for example, the opening diameter: 5 to 15 mm). Thereby, the plastic material can be formed into a flake or pellet shape, making it easier to package.

[0101] Also by this squeezing dehydration and drying step S6, impurities such as sulfur compounds, nitrogen compounds, general bacteria, and Escherichia coli in the plastic material can be decomposed and / or peeled off and removed from the plastic material. In this step, since no additional steps such as the treatment of wastewater such as an aqueous oxidant solution are performed, it is safe and hygienic, and the treatment cost can be suppressed.

[0102] A plurality of plastic materials are gathered by the squeezing dehydration and drying device, heated, squeezed, and sent out. Thereby, moisture is squeezed out and the moisture evaporates, so that dehydrated and dried plastic material is produced. In this way, reusable plastic material is produced. At this time, the moisture content of the plastic material is 5% by mass or less, and preferably 3% or less. Note that the squeezing dehydration and drying may be performed by separate devices.

[0103] Note that the dehydration and drying of the plastic material are not limited to the above-mentioned squeezing dehydration and drying step S6. When the shape of the plastic material is not changed, a general dehydration and drying step may be performed. Examples of the dehydration and drying step include a step of drying the plastic material in a high-temperature atmosphere or hot air in a thermostatic bath. Examples of the drying temperature include 80 to 120 °C. The drying time depends on the drying temperature, but examples include 10 to 120 minutes.

[0104] In this way, the recycled plastic material is manufactured as one aspect of the resin composition according to this embodiment.

[0105] Note that the ratio of the insoluble component in the plastic material (resin composition) can be adjusted, for example, by the second separation step S3 and the washing step S5. In the second separation step S3, for example, by suppressing the degree of separation of insoluble components such as pulp fibers and superabsorbent polymers, the ratio of insoluble components in the plastic material can be increased. In the washing step S5, for example, by suppressing the degree of flushing with the washing liquid, the ratio of insoluble components in the plastic material can be increased.

[0106] On the other hand, in this embodiment, the mixed liquid containing the pulp fibers, superabsorbent polymer, excrement, and acidic aqueous solution separated in the first separation step S2 is treated in the dust removal step S7 to the pulp fiber separation step S10. Then, the recycled pulp fibers and superabsorbent polymer can be used to adjust the composition of the resin composition. Specific description will be given below.

[0107] The dust removal process S7 separates foreign substances such as other materials (collection bags, films, non-woven fabrics, elastic members, etc.) that could not be completely separated from the mixed liquid supplied from the first separation process S2 (and the second separation process S3) by a separator (exemplified: screen separator, cyclone separator). In this embodiment, in the dust removal process S7, a screen separator (relatively large mesh size), a screen separator (relatively small mesh size), and a cyclone separator are arranged in this order, and foreign substances are sequentially separated from the mixed liquid. Thereby, a mixed liquid containing pulp fibers, superabsorbent polymers, excrement, and acidic aqueous solution with less foreign substances is obtained. The mixed liquid is supplied to the SAP separation process S8. Note that when it is not necessary to separate foreign substances in the mixed liquid (exemplified: few foreign substances are contained, foreign substances are separated in other subsequent processes), the dust removal process S7 can be omitted.

[0108] The SAP separation process S8 separates superabsorbent polymers from the mixed liquid containing pulp fibers, superabsorbent polymers, excrement, and acidic aqueous solution with less foreign substances supplied from the dust removal process S7 by a separator (exemplified: drum screen separator). In this embodiment, in the SAP separation process S8, the drum screen separator separates superabsorbent polymers, excrement, and acidic aqueous solution from the mixed liquid. Thereby, superabsorbent polymers, excrement, and acidic aqueous solution are obtained. The mixed liquid containing superabsorbent polymers, excrement, and acidic aqueous solution is removed of excrement and acidic aqueous solution by another separator (exemplified: inclined screen separator), and is sterilized, washed, dried, etc. as necessary, and recovered as superabsorbent polymers. On the other hand, the pulp fibers (containing a small amount of superabsorbent polymers) are supplied to the oxidant treatment process S9.

[0109] In the oxidizing agent treatment step S9, the superabsorbent polymer in the pulp fibers with few foreign substances (however, containing a small amount of superabsorbent polymer) supplied from the SAP separation step S8 is oxidatively decomposed and solubilized with an aqueous oxidizing agent solution, and then removed from the pulp fibers. In the present embodiment, in the oxidizing agent treatment step S9, pulp fibers are introduced into a treatment tank that stores an aqueous oxidizing agent solution containing ozone as the oxidizing agent, and the superabsorbent polymer in the pulp fibers is oxidatively decomposed and solubilized, and pulp fibers with extremely few impurities are obtained. The pulp fibers with few impurities (including the superabsorbent polymer) are supplied to the pulp fiber separation step S10 together with the aqueous oxidizing agent solution.

[0110] The type of the oxidizing agent in the oxidizing agent treatment step S9 is the same as that in the cleaning step S5. In the present embodiment, ozone is used as the oxidizing agent from the viewpoints of oxidizing power, bactericidal power, and bleaching power. The ozone concentration in the aqueous oxidizing agent solution is not particularly limited as long as it can decompose the superabsorbent polymer, and for example, 10 to 50 mass ppm can be mentioned. If the concentration is not too low, the superabsorbent polymer can be completely solubilized, and if the concentration is not too high, the pulp fibers will not be damaged. The treatment time with the aqueous oxidizing agent solution is not particularly limited as long as it can decompose the superabsorbent polymer. If the ozone concentration in the aqueous oxidizing agent solution is high, the treatment time is short, and if the ozone concentration is low, the treatment time is long. Typically, it is 5 to 300 minutes. The product of the ozone concentration (ppm) in the aqueous oxidizing agent solution and the treatment time (minutes) of the treatment step (hereinafter also referred to as the "CT value") is preferably 100 to 15,000 ppm·min. If the CT value is too small, the superabsorbent polymer may not be completely solubilized and the superabsorbent polymer may remain in the pulp fibers. If the CT value is too large, the pulp fibers may be damaged.

[0111] In the pulp fiber separation step S10, the pulp fibers are separated from the pulp fibers and the aqueous oxidizing agent solution supplied from the oxidizing agent treatment step S9 by a separator (example: screen separator). The pulp fibers separated and recovered in this way become so-called recycled pulp fibers. The recycled pulp fibers are washed with washing water and taken out.

[0112] In the mixing step S11, at least one of the superabsorbent polymer taken out in the SAP separation step S8 and the pulp fiber taken out in the pulp fiber separation step S10 is added to the plastic material that has undergone the pressing, dewatering, and drying step S6 as needed, thereby producing a resin composition having a desired ratio of dissolved components and insoluble components. In this embodiment, first, the content (mass%) of the insoluble components, namely pulp fibers and superabsorbent polymers, in the plastic material is measured by the <Method for Measuring Dissolved Components and Insoluble Components> described later. Then, when the ratio of the insoluble components is less than the desired ratio, the pulp fibers or superabsorbent polymers, which are insoluble components, are added to the plastic material. When there is no excess or deficiency in the ratio of the dissolved components and insoluble components, the plastic material is used as the resin composition as it is. When the ratio of the insoluble components is more than the desired ratio, another separately taken-out plastic material may be added to the plastic material that has undergone the pressing, dewatering, and drying step S6.

[0113] In this way, a recycled plastic material whose composition is adjusted using the recycled pulp fibers and superabsorbent polymer (or another plastic material) is produced as another aspect of the resin composition according to this embodiment.

[0114] In the method for producing a resin composition derived from a used sanitary product containing excrement according to this embodiment, a first fraction is separated in the first separation step S2. At this time, since the superabsorbent polymer that has absorbed urine or the like is inactivated, sodium and nitrogen compounds are released (dehydrated) to the outside together with moisture and are in a granular state. Therefore, in the second separation step, the superabsorbent polymer in the first fraction can be easily separated from the plastic material by physical impact. In addition, even if there is a superabsorbent polymer that cannot be completely separated from the plastic material, the content of sodium and nitrogen compounds in the superabsorbent polymer can be reduced. Also, other excrement and pulp fibers can be easily separated from the plastic material by physical impact.

[0115] Subsequently, a cleaning step S5 (oxidizing agent treatment step) is performed on the plastic material separated in the second separation step S3. At this time, sulfur compounds, nitrogen compounds, etc. derived from excrement remaining in the plastic material that could not be completely separated in the second separation step S3 are oxidized and converted into odorless other substances (for example, sulfur (S) and nitrogen (N2)), and part or all of such substances are mixed into the oxidizing agent aqueous solution and / or released as gas. That is, most of the sulfur compounds and nitrogen compounds remaining in the plastic material are removed. In this way, since the odor-emitting sulfur compounds and nitrogen compounds are converted into odorless other substances and generally removed, it is possible to make it difficult for the plastic material to generate a bad odor. Also, the plastic material can be sterilized with an oxidizing agent. At that time, by supplying the oxidizing agent aqueous solution to the plastic material by spraying, sulfur compounds, nitrogen compounds, etc. adhering to the surface of the plastic material can be washed off by the momentum of the spraying. Also, by making the oxidizing agent aqueous solution fine by spraying and supplying it to the plastic material, it is possible to easily let the oxidizing agent aqueous solution enter into the details of the plastic material. Also, compared with the case of immersing the plastic material in the oxidizing agent aqueous solution, a fresh oxidizing agent aqueous solution can always be supplied to the surface of the plastic material, and the variation in the effects of cleaning and sterilization can be reduced.

[0116] Thus, in the plastic material manufactured by this method, impurities containing sodium, sulfur, and nitrogen are separated and removed, so that the impurities of the plastic material can be suppressed. Also, sterilization can be performed at the same time. And when manufacturing a recycled product by applying the plastic material to material recycling or chemical recycling, since the impurities of the plastic material are suppressed, the influence on the catalyst used in the manufacturing process can be reduced, and it is possible to make it difficult to generate an unfavorable odor.

[0117] In the method for producing the resin composition, as a preferred embodiment, in the second separation step S3, an acidic aqueous solution is sprayed onto the first fraction while applying a physical shock to separate the excrement, superabsorbent polymer, and pulp fibers from the plastic material. Thus, in this method, in the second separation step S3, an acidic aqueous solution is sprayed onto the first fraction. Therefore, the superabsorbent polymer remaining in the plastic material is further inactivated by the acidic aqueous solution, further releasing (dehydrating) sodium and nitrogen compounds to the outside, and becoming finer particles. Therefore, the superabsorbent polymer can be more easily separated from the plastic material by the physical shock or the flow of the acidic aqueous solution. In addition, even if there is a superabsorbent polymer that cannot be completely separated from the plastic material, the content of sodium and nitrogen compounds in the superabsorbent polymer can be further reduced. Also, other excrement and pulp fibers can be more easily separated from the plastic material by the physical shock or the flow of the acidic aqueous solution.

[0118] In the method for producing the resin composition, as a preferred embodiment, it further includes a squeezing dehydration drying step S6 for squeezing and dehydrating and drying the plastic material treated in the washing step S5. That is, since the plastic material treated in the washing step S5 is squeezed and dehydrated while being dried, the moisture in the plastic material can be further reduced. Thereby, in the washing step S5 or the like, impurities (for example, substances containing sulfur and nitrogen that do not generate a bad odor) mixed in the moisture (aqueous solution) can be discharged from the plastic material together with the moisture.

[0119] <Method for Measuring Dissolved Components and Insoluble Components> The dissolved components and insoluble components in the resin composition are measured as follows. (1) First, for each of the dissolved components and insoluble components in the resin composition, component separation is performed by utilizing the difference in the solubility of the components in various solvents. Specifically, it is as follows. First, a sample of the resin composition to be measured is dissolved and dispersed in tetrahydrofuran (THF), filtered and separated (5 μm filter), and divided into a solvent-soluble component and a solvent-insoluble component. The solvent-soluble component of THF is centrifuged (12,000 rpm × 0.5 h) and divided into a solvent-insoluble component (F11) and a solvent-soluble component. The solvent-soluble component after centrifugation is dissolved and dispersed in methanol, filtered and separated (3 μm filter), and divided into a solvent-insoluble component (F12) and a solvent-soluble component (F13). The solvent-insoluble component of THF is dissolved and dispersed in hexafluoroisopropanol (HFIP), filtered and separated (5 μm filter), and divided into a solvent-soluble component and a solvent-insoluble component. The solvent-soluble component of HFIP is dissolved and dispersed in methanol, filtered and separated (3 μm filter), and divided into a solvent-insoluble component (F21) and a solvent-soluble component (F22). The solvent-insoluble component of HFIP is dissolved and dispersed in heated xylene, filtered and separated (200 mesh), and divided into a solvent-soluble component and a solvent-insoluble component (F31). The solvent-soluble component of xylene is dissolved and dispersed in methanol, filtered and separated (3 μm filter), and divided into a solvent-insoluble component (F32) and a solvent-soluble component (F33). (2) Next, IR analysis is performed on each fraction (F11 - F13, F21 - F22, F31 - F33, F41 - F43) after separation. (3) For the mixture of fraction F12 and fraction F13, solution 1 1H NMR is performed. (4) For fraction F32, high-temperature 13 13C NMR is performed. (5) Fraction F31 is carbonized in an electric furnace (570 °C, 2 h), the residue is taken as ash, and the weight loss fraction is taken as pulp fiber. (6) Based on the results of (2) to (5) above, the ratios and qualitative results of the dissolved components and the undissolved components are determined.

[0120] <Method for measuring sound absorption> The method for measuring the sound absorption of a sound-absorbing material using a resin composition is as follows. (1) The measurement conditions are as follows. Measurement target frequency: 100 - 5000 Hz (1 / 3 octave band) Sound source: Wideband noise (pink noise) in the 100 - 5000 Hz band Sound receiving positions: Three points (microphone heights: 1.2 m, 1.35 m, 1.5 m above the floor) (Isolated by a straight - line distance of 1 m or more from the test specimen and the wall) Number of measurements: 3 times at each sound receiving point Test specimen arrangement i) Align the long side of the test specimen (about 3 kg / bag) parallel to the long side of the test specimen laying area and place it near the north side within the area Number of test specimens: 35 bags (9.42 m 2 ) Test temperature and humidity: 10°C, 71% ii) Align the long side of the test specimen (about 4 kg / bag) parallel to the long side of the test specimen laying area and place it near the south side within the area Number of test specimens: 35 bags (9.42 m 2 ) Test temperature and humidity: 10°C, 72% iii) Align the long side of the test specimen (about 4 kg / bag) perpendicular to the long side of the test specimen laying area and place it near the north side within the area Number of test specimens: 36 bags (9.515 m 2 ) Test temperature and humidity: 10°C, 71% Note: This measurement method complies with JIS - A - 1409 (Measurement method for sound absorption coefficient by reverberation room method). The reverberation room has a floor shape of a nearly square, the test specimen laying area is a rectangular area separated from each wall surface at the center of the reverberation room, and the speaker is located on the east side of the test specimen laying area. (2) Perform measurements for test specimen arrangements (i) - (iii) and take the average as the final measurement value.

[0121] <Measurement method for sulfur, nitrogen, aluminum, and chlorine contents>[[]]END]] The measurement methods for the sulfur, nitrogen, aluminum, and chlorine contents (mass%) of the resin composition and the solid fuel are as follows. (1) Prepare an energy - dispersive X - ray analyzer (EDX: EDX - 7200 manufactured by Shimadzu Corporation). (2) Dry the resin composition or solid fuel to be measured (120 °C × 60 minutes), and collect a sufficient amount of sample from the dried resin composition or solid fuel that can be placed on the sample stage of the analyzer and is sufficient for measurement, and fix it to the sample stage. (3) Measure the sulfur, nitrogen, aluminum, and chlorine contents in the sample using an analyzer. (4) Average the measurement results of the five samples to obtain the sulfur, nitrogen, sodium, and chlorine contents in the final resin composition.

[0122] <Method for Measuring Higher Heating Value, and Mass Fraction of Moisture and Ash> The higher heating value (MJ / kg) of the resin composition and solid fuel to be measured is determined by a method conforming to JIS Z 7302-2. The mass fraction (%) of moisture in the resin composition and solid fuel to be measured is determined by a method conforming to JIS Z 7302-3. The mass fraction (%) of ash in the resin composition and solid fuel to be measured is determined by a method conforming to JIS Z 7302-4.

[0123] <Method for Measuring Bulk Specific Gravity> The bulk specific gravity of the resin composition and solid fuel is determined as follows. First, measure the total mass of the resin composition or solid fuel when the resin composition or solid fuel to be measured is filled to the brim in a container with a certain volume (for example, 1 L). Then, divide the measured mass by the mass of water with the same volume as the container to obtain the bulk specific gravity of the resin composition or solid fuel to be measured.

[0124] <Method for Measuring Escherichia coli> The method for measuring Escherichia coli in the resin composition and solid fuel is as follows. (1) Prepare 500 g of an aqueous dispersion with a solid content concentration of 5.0 mass% of the resin composition or solid fuel to be inspected in a 1-liter beaker. · When the above resin composition or solid fuel exists in a dry state The above aqueous dispersion can be formed by mixing the above resin composition or solid fuel (25.0 g as solid content) and deionized water (in an amount such that the total amount is 500.0 g). ·When the above resin composition or solid fuel exists as an aqueous solution (for example, when the resin composition or solid fuel is recovered as an aqueous solution in the method for producing the resin composition or solid fuel), and the solid content concentration of the resin composition or solid fuel is 5.0 mass% or more By adding deionized water to the aqueous solution or the like, an aqueous dispersion having a solid content concentration of 5.0 mass% of the resin composition or solid fuel can be prepared. ·When the above resin composition or solid fuel exists as an aqueous solution, and the solid content concentration of the resin composition or solid fuel is less than 5.0 mass% By filtration, the solid content concentration of the resin composition or solid fuel is adjusted to 5.0 mass%, or the above aqueous solution itself is used as an aqueous dispersion, and the inoculum amount of the step-diluted sample described later is increased (for example, when the solid content concentration of the resin composition or solid fuel is 2.5 mass%, the inoculum amount is doubled). (2) Stir the above aqueous dispersion at a rotation speed of 300 rpm for 15 minutes using an overhead stirrer. (3) Put 50 mL of the aqueous dispersion stirred using an overhead stirrer into a sterilized bag with a filter (manufactured by LMS, sterilized bag with a homogenizer filter), and stir for 5 minutes. (4) Dispense the filtered aqueous dispersion filtered with a sterilized bag with a filter into a sterilized test tube, and perform 10-fold serial dilution up to 10 -9 Dispense into sterilized test tubes to prepare step-diluted samples. (5) The number of Escherichia coli is measured by the pour plate method. Specifically, put 1 mL of the step-diluted sample and a standard agar medium (manufactured by Shioya MS Co., Ltd., 399-02201 EMB agar medium for Escherichia coli inspection "Digo", 15 to 20 g) into a petri dish, and perform pour plate culture at 35 °C for 48 hours. (6) As the number of Escherichia coli, count the number of colonies grown after culture. Note that 10 -9In all the serially diluted samples diluted 10-fold up to a certain point, when the number of colonies is zero, it is determined that the target bacteria are "not detected", that is, the number of viable bacteria detected by the mixed culture method is below the detection limit. In other words, the number of viable bacteria is 0 cfu / g. (7) After culturing, when colonies of intestinal bacteria or viable bacteria are formed, the type of bacteria can be identified. The identification can be performed by a biochemical property test method.

Examples

[0125] Hereinafter, the present invention will be described based on examples, but the present invention is not limited to the examples.

[0126] (1) Sample Example 1: Using a used disposable diaper containing excrement as a raw material, the crushing step S1 to the pressing, dewatering and drying step S6 of the method for producing a resin composition derived from a used sanitary product containing excrement according to the present embodiment were performed to obtain the resin composition of Example 1. However, the acidic aqueous solution in the second separation step S3 was a 0.1 mass% sulfuric acid aqueous solution, and the cleaning liquid in the cleaning step S5 was water. Example 2: Using the resin composition of Example 1, the sound-absorbing material of Example 2 was formed. However, the sound-absorbing material was prepared by packing 4 kg of the resin composition into a polyethylene resin bag of 570 mm × 440 mm × 50 mm. 36 such sound-absorbing materials were prepared. Example 3: Using the resin composition of Example 1, the solid fuel of Example 3 was formed by extrusion molding (10 kg / cm 2 , 150 °C, 10 minutes).

[0127] (2) Evaluation method (a) Composition of the resin composition Regarding the resin composition of Example 1, the dissolved components and the insoluble components were measured by the above-mentioned <Measurement method of dissolved components and insoluble components>. (b) Sound absorption of the sound-absorbing material Regarding the following sound-absorbing materials, the sound absorption was measured by the above-mentioned <Measurement method of sound absorption>. · The sound-absorbing material of Example 2 · Commercially available glass wool 24K (1 m2 High-performance glass wool with a density of 24 kg per square meter - Sound-absorbing material with a thickness of 50 mm (Comparative Example 1) · Commercial glass wool 24K - Sound-absorbing material with a thickness of 25 mm (Comparative Example 2) · Commercial rock wool acoustic board - Thickness of 12 mm (Comparative Example 3) (c) Composition of solid fuel, etc. Regarding the resin composition of Example 1 and the solid fuel of Example 3, according to the above <Measurement methods for higher heating value, mass fraction of moisture and ash>, <Measurement methods for sulfur, nitrogen, aluminum, and chlorine contents>, <Measurement method for bulk specific gravity>, <Measurement method for Escherichia coli>, the respective higher heating values, mass fractions of moisture and ash, sulfur, chlorine, nitrogen, and aluminum contents, bulk specific gravity composition, and Escherichia coli were measured.

[0128] (3) Evaluation results (a) Composition of resin composition The measurement results of the composition of the resin composition of Example 1 are shown in Table 1 below. In the resin composition of Example 1, polypropylene and polyethylene, which are polyolefin-based resins as the dissolved components, were 46.2% by mass and 17.0% by mass, respectively. Polyethylene terephthalate, which is a polyester-based resin as the dissolved component, was 9.1% by mass. Styrene-containing polymer (styrene), which is the dissolved component, was 1.9% by mass. Hydrocarbons that may contain polyurethane as the dissolved component were 8.2% by mass. In addition, butadiene, which is the dissolved component, and oligomers and additives were 0.9% by mass and 0.3% by mass, respectively. On the other hand, pulp fibers (cellulose) and inorganic compounds (calcium carbonate), which are insoluble components, were 14.7% by mass and 1.7% by mass, respectively. Therefore, the dissolved component was 83.6% by mass, and the insoluble component was 16.4% by mass. Also, the proportion of the polyolefin-based resin in the dissolved component was 75.6% by mass. Moreover, the proportion of pulp fibers (cellulose) and inorganic compounds (calcium carbonate) in the insoluble component was almost 100% by mass. Also, as will be described later, in the resin composition of Example 1, the contents of sulfur, chlorine, nitrogen, and aluminum were extremely low, and Escherichia coli was not detected either.

[0129]

Table 1

[0130] (b) Sound absorption property of sound-absorbing material The measurement results of the sound absorption property of the sound-absorbing material of Example 2 are shown in Fig. 2. In the graph of the figure, the vertical axis represents the reverberation room sound absorption rate, and the horizontal axis represents the 1 / 3 octave band center frequency (Hz). However, the solid circles indicate the results of Example 2, the crosses indicate the results of Comparative Example 1 (glass wool 24K - thickness 50 mm), the diamonds indicate the results of Comparative Example 2 (glass wool 24K - thickness 25 mm), and the triangles indicate the results of Comparative Example 3 (rock wool board - thickness 12 mm). From the graph, the sound-absorbing material of Example 2 showed a better high sound absorption rate than the rock wool board of Comparative Example 3, and showed characteristics equivalent to or better than those of the glass wool of Comparative Example 1 and Comparative Example 2 at frequencies higher than 1000 Hz.

[0131] (c) Composition of solid fuel, etc. The measurement results of the resin composition of Example 1 and the composition of the solid fuel of Example 3, etc. are shown in Table 2 below. The resin composition of Example 1 had an extremely high higher heating value of 39.1 MJ / kg, and the contents of moisture, ash, sulfur, chlorine, nitrogen, and aluminum were extremely low, 0.7 mass%, 2.68 mass%, 0.022 mass%, 0.020 mass%, less than 0.30 mass%, and less than 0.10 mass% respectively, and Escherichia coli was not detected. The bulk specific gravity was slightly low at 0.199. Therefore, except for the bulk specific gravity, it had characteristics conforming not only to Grade A of Variety RPF in the quality standard of RPF (Refuse derived paper and plastics densified Fuel) (JIS Z7311:2010 "Solidified fuel (RPF) from waste such as paper and plastics"), but also to Variety RPF - coke. The solid fuel of Example 3 had an extremely high higher heating value of 36.5 MJ / kg, and the contents of moisture, ash, sulfur, chlorine, nitrogen, and aluminum were extremely low at 0.7% by mass, 2.08% by mass, 0.015% by mass, 0.039% by mass, less than 0.30% by mass, and less than 0.10% by mass, respectively, and no Escherichia coli was detected. The bulk specific gravity was 0.392. Therefore, it had characteristics that conformed not only to Grade A of Variety RPF but also to Variety RPF-coke in the quality standards of RPF.

[0132]

Table 2

[0133] The resin composition of the present invention and the products using the same are not limited to the above-described embodiments, and appropriate combinations, changes, etc. are possible within the scope not departing from the object and gist of the present invention.

Explanation of Reference Numerals

[0134] S1 Crushing process S2 First separation process S3 Second separation process S4 Air conveyance process S5 Washing process S6 Pressing dehydration and drying process S7 Dust removal process S8 SAP separation process S9 Second oxidant treatment process S10 Pulp fiber separation process S11 Mixing process

Claims

1. A resin composition derived from used sanitary products containing excreta, comprising a soluble component and an insoluble component, wherein the proportion of the soluble component is 80 to 90% by mass, the proportion of the insoluble component is 10 to 19% by mass, and the proportion of nitrogen atoms contained in the resin composition is less than 0.5% by mass. Resin composition.

2. The soluble component contains a polyolefin resin as a main component, The resin composition according to Claim 1.

3. The soluble component further contains a polyester resin, The resin composition according to Claim 2.

4. The polyester resin contains polyethylene terephthalate, The resin composition according to Claim 3.

5. The soluble component further contains at least one of polyurethane and a styrene-containing polymer, The resin composition according to Claim 2.

6. The insoluble component contains at least one of cellulose fibers, superabsorbent polymers, and inorganic compounds, The resin composition according to Claim 1 or 2.

7. The proportion of ash contained in the resin composition is less than 4% by mass, The resin composition according to Claim 1 or 2.

8. The proportion of chlorine atoms contained in the resin composition is less than 0.1% by mass, The resin composition according to Claim 1 or 2.

9. Escherichia coli contained in the resin composition is below the detection limit, The resin composition according to Claim 1 or 2.

10. The proportion of sulfur atoms contained in the resin composition is less than 0.1% by mass, The resin composition according to Claim 1 or 2.

11. Containing the resin composition according to Claim 1 or 2, Sound-absorbing material.

12. Containing the resin composition according to Claim 1 or 2, with a bulk specific gravity of 0.3 to 0.5, Solid fuel.

13. Containing the resin composition according to Claim 1 or 2, Container.

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