Abstract: A recycled pulp that is reusable sanitary products is efficiently manufactured by recovering pulp fiber from used sanitary products containing the pulp fiber and a polymer absorbent. The method of the present invention comprises: a step applying a mechanical force to the used sanitary products in an aqueous solution containing a polyvalent metal ion or an acidic aqueous solution with a pH of 2.5 or lower and thus degrading the used sanitary products into the pulp fiber and other materials; a step separating the pulp fiber from the mixture of the pulp fiber and other materials that has been formed in the degradation step; and a step treating the pulp fiber thus separated with an ozone-containing aqueous solution with a pH of 2.5 or lower.

Abstract: A method is provided for recovering pulp fibers having little damage from a used absorbent article which includes a water permeable front sheet, a water impermeable back sheet and an absorbent body that contains pulp fibers and a superabsorbent polymer. At least one opening with a circle equivalent diameter of 5-45 mm, or 10-45 mm cut, is made in the front sheet and/or the back sheet of the used absorbent article, which is then agitated in an organic acid aqueous solution with a pH of less than or equal to 2.5, and the superabsorbent polymer is deactivated and the pulp fibers and superabsorbent polymer are discharged from the used absorbent article through the opening or cut.

Abstract: A method of recovering structural members from a used absorbent article comprising a front sheet, a back sheet and an absorbent body between the front sheet and the back sheet, wherein at least one of the front sheet and the back sheet includes a film, and wherein the absorbent body includes an absorbent body material, may include swelling the used absorbent article with water, applying a physical shock to and disintegrating the swelled used absorbent article into at least the film and the absorbent body material, and separating the film and the absorbent body material.

Abstract: A method is provided which, by a simple process, separates and recovers pulp fibers from a used absorbent article that contains pulp fibers and a superabsorbent polymer. A used absorbent article is treated with an aqueous solution that contains greater than or equal to 0.05 mass % of at least one kind of terpene selected from the group comprising terpene hydrocarbons, terpene aldehydes, and terpene ketones and that contains a deactivating agent that can deactivate the superabsorbent polymer; the superabsorbent polymer is deactivated, the adhesive that bonds together the constituent materials of the absorbent article is dissolved with the terpene to decompose the absorbent article, the pulp fibers are discharged to outside of the absorbent article, and the pulp fibers are separated from the absorbent article and recovered.

Abstract: A method includes producing recycled products from a plurality of used absorbent articles, each including a top sheet, a back sheet and an absorbent body including absorbent body materials, by recovering a plurality of structural members from the plurality of used absorbent articles. At least one of the top sheet and the back sheet includes a film. The method includes: separating the plurality of used absorbent articles into a plurality of the films and the absorbent body materials; sorting the plurality of films into a plurality of types of recyclable films according to the filler contents of the plurality of films; and forming a plurality of types of recycled resin pellets from the plurality of types of recyclable films.

Abstract: A method of recycling a used absorbent article having human waste includes: a first step of separating pulp fiber from the used absorbent article to obtain regenerated pulp fiber; a second step of conversion to solid fuel from constituent materials of the used absorbent article remaining after separation of the pulp fiber to obtain solid fuel, and a third step of supplying waste water containing organic material generated from the first step to a microbial fuel cell to obtain electric power while purifying the waste water. The processing rate for the used absorbent article containing human waste is 90 mass % or greater.

Abstract: A method is provided which, by a simple process, separates and recovers pulp fibers from a used absorbent article that contains pulp fibers and a superabsorbent polymer. A used absorbent article is treated with an aqueous solution that contains greater than or equal to 0.05 mass % of at least one kind of terpene selected from the group comprising terpene hydrocarbons, terpene aldehydes, and terpene ketones and that contains a deactivating agent that can deactivate the superabsorbent polymer; the superabsorbent polymer is deactivated, the adhesive that bonds together the constituent materials of the absorbent article is dissolved with the terpene to decompose the absorbent article, the pulp fibers are discharged to outside of the absorbent article, and the pulp fibers are separated from the absorbent article and recovered.

Abstract: A method of recovering urine-derived nutrient salts from a used absorbent article containing urine, includes: immersing the used absorbent article in an aqueous solution containing a calcium compound to deactivate a superabsorbent polymer; using a sieve to separate a solid-liquid mixture yielded by the deactivation into a first fraction containing the constituent materials of the absorbent article, and a second fraction containing an aqueous solution containing the calcium compound and nutrient salts, and nutrient-salt-containing sediment that has passed through the sieve; producing nutrient-salt-containing sediment using a HAP method; and adjusting the pH of the aqueous solution in contact with the nutrient-salt-containing sediment to within a range of 5.6-7.0, dissolving at least some of a calcium compound other than hydroxyapatite in the sediment, and increasing the hydroxyapatite content of the sediment.

Abstract: An absorbent article may include a top sheet that is liquid-permeable, a back sheet that is liquid-impermeable, and an absorbent body situated between the top sheet and the back sheet in a thickness direction. At least one of the top sheet and the back sheet may include a synthetic resin sheet that includes a synthetic resin component and an oxidative decomposer comprising a mixture of a carboxylate and a rare earth compound. The synthetic resin sheet may contain the oxidative decomposer in a mass ratio such that a decomposition rate index (Di), as determined by formula (1), is 7.8 or less: Di=Br×Sa ??(1) where Br represents a mass ratio (g/g) of the oxidative decomposer with respect to the synthetic resin component, and Sa represents a specific surface area (cm2/g) of the synthetic resin sheet.

Abstract: Pulp fiber containing little ash is effectively recovered from a used sanitary product containing the pulp fiber and a polymer absorbent. The method according to the present invention comprises: a step for treating the used sanitary product with an ozone-containing gas and thus decomposing and removing at least a portion of the polymer absorbent in the used sanitary product; and a step for stirring the used sanitary product, that has been treated with the ozone-containing gas, in water or an aqueous solution containing an antiseptic and thus decomposing the used sanitary product into constituents. If required, the method may further comprise a step for separating the pulp fiber from the decomposition product obtained by the decomposition step.

Abstract: Disclosed is water-disintegrable nonwoven fabric which comprises 15-30 mass % regenerated cellulose fibers having a fiber length of 3-4 mm and a fineness of 0.3 dtex or less and 70-85 mass % pulp, has a basis weight of 35-50 g/m2, has a tendency to disentanglement of 100 seconds or less when examined by a disentanglement test according to JIS P 4501:1993, and has a wet tensile strength of 1.2 N/25 mm or greater. The water-disintegrable nonwoven fabric combines wet tensile strength during use with water disintegrability after use.

Abstract: A simple method is provided for producing a saccharified solution from a used absorbent article such as a used diaper. In order to produce a saccharified solution from a used absorbent article comprising a non-cellulosic liquid permeable surface material and an absorbent body that contains pulp fibers, the used absorbent article is immersed, without first being decomposed, in a saccharifying enzyme solution containing cellulase. The pulp fibers in the used absorbent article are saccharified by the cellulase, producing a saccharified solution. The produced saccharified solution is exuded out of the used absorbent article through the liquid permeable surface material, so it is possible to easily separate and recover the saccharified solution from the used absorbent article while maintaining the outer shape.

Abstract: Provided is a process for recovering pulp fiber from used sanitary goods which contain both pulp fiber and a superabsorbent polymer and producing a recycled pulp which contains little ash and which is reusable for sanitary goods. This process comprises: a calcium treatment step for treating used sanitary goods with a water-soluble calcium compound and thereby conducting the dehydration of a superabsorbent polymer contained in the used sanitary goods; a disintegration step for applying a physical force to the used sanitary goods to disintegrate the used sanitary goods into pulp fiber and other materials; a separation step for separating the pulp fiber from a pulp fiber/other materials mixture which has been formed in the disintegration step; a disinfecting step using a disinfectant; and a citric acid treatment step for subjecting the separated pulp fiber to treatment with an aqueous citric acid solution at an acidic pH.

Abstract: A method is provided for recovering pulp fibers having little damage from a used absorbent article which includes a water permeable front sheet, a water impermeable back sheet and an absorbent body that contains pulp fibers and a superabsorbent polymer. At least one opening with a circle equivalent diameter of 5-45 mm, or 10-45 mm cut, is made in the front sheet and/or the back sheet of the used absorbent article, which is then agitated in an organic acid aqueous solution with a pH of less than or equal to 2.5, and the superabsorbent polymer is deactivated and the pulp fibers and superabsorbent polymer are discharged from the used absorbent article through the opening or cut.

Abstract: A method is provided for recovering pulp fibers having little damage from a used absorbent article that contains pulp fibers and a superabsorbent polymer. The used absorbent article is treated at a temperature of greater than or equal to 80° C. with an organic acid aqueous solution having a pH no greater than 2.5, and the superabsorbent polymer is deactivated. Preferably, the pulp fibers and the deactivated superabsorbent polymer are separated from the used absorbent article after treatment with the organic acid aqueous solution, and further, a mixture including the separated pulp fibers and deactivated superabsorbent polymer is treated with an oxidizing agent, the deactivated superabsorbent polymer is decomposed, reduced in molecular weight and solubilized.

Abstract: Provided is a process for recovering pulp fiber from used sanitary goods which contain both pulp fiber and a superabsorbent polymer and producing a recycled pulp which contains little ash and which is reusable for sanitary goods. This process comprises: a calcium treatment step for treating used sanitary goods with a water-soluble calcium compound and thereby conducting the dehydration of a superabsorbent polymer contained in the used sanitary goods; a disintegration step for applying a physical force to the used sanitary goods to disintegrate the used sanitary goods into pulp fiber and other materials; a separation step for separating the pulp fiber from a pulp fiber/other materials mixture which has been formed in the disintegration step; a disinfecting step using a disinfectant; and a citric acid treatment step for subjecting the separated pulp fiber to treatment with an aqueous citric acid solution at an acidic pH.

Abstract: Provided is a method for efficiently recovering pulp fibers with a high degree of safety and without detriment to the performance of the pulp fibers, from used absorbent articles such as disposable diapers containing pulp fibers and a super absorbent polymer. This method comprises: a step for extracting a mixture of pulp fibers, super absorbent polymer and water from used absorbent articles; a step of using a pair of electrodes to apply a voltage to the mixture of pulp fibers, super absorbent polymer and water to deactivate the super absorbent polymer; and a step for separating pulp fibers from the mixture of pulp fibers, deactivated super polymer and water.

Abstract: Pulp fiber containing little ash is effectively recovered from a used sanitary product containing the pulp fiber and a polymer absorbent. The method according to the present invention comprises: a step for treating the used sanitary product with an ozone-containing gas and thus decomposing and removing at least a portion of the polymer absorbent in the used sanitary product; and a step for stirring the used sanitary product, that has been treated with the ozone-containing gas, in water or an aqueous solution containing an antiseptic and thus decomposing the used sanitary product into constituents. If required, the method may further comprise a step for separating the pulp fiber from the decomposition product obtained by the decomposition step.

Abstract: Provided is a method for efficiently recovering pulp fiber from used hygiene products that include pulp fiber and a polymer absorbent. This method is characterized by including a step for introducing the used hygiene product into a treatment tank in which an aqueous solution with ozone dissolved therein has been introduced, and a step for treating the used hygiene product while infusing water into the treatment tank at a first flow rate, extracting the aqueous solution from the treatment tank at a second flow rate and introducing a gas containing ozone into the aqueous solution in the treatment tank, thereby decomposing the polymer absorbent, lowering the molecular weight thereof, and making the same dissolvable.

Abstract: Provided is a method for treating a used absorbent article, this method being hygienic and capable of recovering recyclable material with a high degree of safety. This method for treating a used absorbent article is characterized by including (a) an acidic electrolyzed water treatment step that treats the used absorbent article in a treatment tank that has acidic electrolyzed water serve as a treatment fluid. This method preferably further includes (b) an alkaline electrolyzed water treatment step that treats the used absorbent article in a treatment tank that has alkaline electrolyzed water as a treatment fluid.