Bale manufacturing method

Abstract

To provide a bale manufacturing method which reduces the number of bacteria attached to used paper contained in a bale, is excellent in putrefaction resistance, and is also excellent in disintegration property of the used paper contained in the bale.SOLUTION: A bale manufacturing method includes a cleaning step of cleaning used paper having at least a resin layer and a paper base material layer with cleaning water containing an oxidant, and a molding step of compression molding the used paper to obtain a bale, wherein the basis weight of the used paper is 100 g / m2 or more, and a central value of the area of the used paper is 20 cm2 or more and 150 cm2 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a bale. [Background technology]

[0002] In recent years, growing interest in waste reduction and environmental issues has led to an acceleration of efforts to eliminate plastic use worldwide. To reduce the amount of plastic used in various products, efforts are being made to change from solely plastic raw materials to laminated paper, which is made by laminating a paper base material with a resin layer or other material. This laminated recycled paper is particularly used for food packaging, such as food containers. Conventionally, laminated paper was considered taboo and was not recycled, but with increasing interest in reducing waste and environmental issues, there is now a demand for the reuse of laminated paper as recycled paper. Generally, waste paper is temporarily stored in bales for recycling.

[0003] Patent Document 1 discloses an apparatus for forming bales from compressible waste materials such as waste paper and discarded cartons. The apparatus has a substantially rectangular parallelepiped shape and includes a press housing having at least one compression chamber and a press plate that can be reciprocated in the pressing direction within the compression chamber by a drive means. Furthermore, Patent Document 2 discloses a bale press for compressing paper, cardboard, etc., which has a load chamber that receives material to be compressed and baled by a piston mechanism that reciprocates within the chamber, and a choke chamber that is formed at the outlet of the load chamber, holds the compressed material by frictional force, and presses new material against the held material by the piston mechanism. Furthermore, Patent Document 3 discloses a crushing and washing device for recycling both used paper containers and filled, unusable paper containers, characterized in that it is configured with a receiving hopper (14) for receiving used paper containers (16) and filled unusable paper containers in the initial process of recycling paper containers, an input conveyor (15) for carrying these paper containers to a crusher (1), the crusher (1) for crushing these paper containers into scraps (2), a screw conveyor (3) sealed in a housing and installed at an angle for conveying the scraps (2) while cleaning them, and a scrap receiver (10) for storing the cleaned scraps (7). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2010-521312 [Patent Document 2] International Publication No. 1998 / 33643 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-314825 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, waste paper is formed into bales using bale-forming devices such as those disclosed in Patent Documents 1 and 2, and then recycled. However, waste paper used as food packaging, in particular, can become difficult to recycle due to the proliferation of bacteria caused by food and other contaminants remaining on the waste paper, which can lead to the progression of decay. Furthermore, Patent Document 3 discloses a method of washing waste paper with tap water in a device for shredding and washing waste paper, but these washing methods sometimes fail to fully remove food and other contaminants remaining on the waste paper. Furthermore, depending on the condition of the formed bale, the waste paper contained in the bale may not be sufficiently disintegrated, reducing recyclability. An object of the present invention is to provide a method for producing a bale in which the number of bacteria adhering to the waste paper contained in the bale is reduced, the bale has excellent putrefaction resistance, and the waste paper contained in the bale also has excellent disintegration properties. [Means for solving the problem]

[0006] The present inventors have discovered that in a bale manufacturing method that includes a washing step in which paper is washed and a molding step in which the waste paper is compressed and molded to obtain a bale, the above-mentioned problems can be solved by using a washing solution containing an oxidizing agent as the washing water in the washing step. The present invention relates to the following [1] to

[10] . [1] A method for producing recycled paper having at least a resin layer and a paper base layer, comprising: a washing step of washing recycled paper having at least a resin layer and a paper base layer with washing water containing an oxidizing agent; and a molding step of compressing and molding the recycled paper to obtain a bale, wherein the basis weight of the recycled paper is 100 g / m 2 or more, and the median area of ​​the waste paper is 20 cm 2 More than 150cm 2 The following is a method for manufacturing a veil. [2] The method for producing a veil according to [1], wherein the oxidizing agent is one or more selected from hydrogen peroxide, ozone, and sodium hypochlorite. [3] The thickness of the waste paper after storing for 7 days is 1 cm. 2 The number of bacteria adhering to the surface per unit area is 10 CFU / cm 2 The method for producing a veil according to [1] or [2], wherein the veil is less than 100%. [4] The median density of the waste paper is 0.70 g / cm 3 The method for producing a bale according to any one of [1] to [3] above. [5] The method for manufacturing a bale according to any one of [1] to [4], wherein the water absorbency of the waste paper is 25% or more and 85% or less. [6] The method for producing a bale according to any one of [1] to [5], wherein the content of the sizing agent in the paper base layer of the recycled paper is 0.2% by mass or more and 2.1% by mass or less. [7] The method for producing a bale according to any one of [1] to [6], wherein the waste paper further has a metal layer. [8] The molding pressure during the molding process is 500 kN / m 2 More than 2500kN / m 2 The method for producing a bale according to any one of [1] to [7] below. [9] Bale density is 0.3t / m 3 More than 1.0t / m 3 The method for producing a bale according to any one of [1] to [8] below.

[10] The method for producing a bale according to any one of [1] to [9], further comprising a crushing step of crushing waste paper before the molding step. [Effects of the Invention]

[0007] According to the present invention, a method for producing a bale is provided in which the number of bacteria attached to the waste paper contained in the bale is reduced, the bale has excellent putrefaction resistance, and the waste paper contained in the bale also has excellent disintegration properties. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Bale manufacturing method] The method for producing a bale of this embodiment includes, in this order, a washing step of washing waste paper having at least a resin layer and a paper base layer with washing water containing an oxidizing agent, and a molding step of compressing and molding the waste paper to obtain a bale, and the basis weight of the waste paper is 100 g / m. 2 or more, and the median area of ​​the waste paper is 20 cm 2 More than 150cm 2 The following is the result. According to the bale manufacturing method of this embodiment, the number of bacteria attached to the waste paper contained in the bale is reduced, the bale has excellent putrefaction resistance, and the waste paper contained in the bale also has excellent disintegration properties. The reason for this is not clear, but it is thought to be as follows. Generally, it has at least a resin layer and a paper base layer, and has a basis weight of 100 g / m 2Such laminated paper is often used as food packaging. Therefore, when recycled, the proteins from food and other materials remaining in the recycled paper serve as a nutrient source for bacterial growth, which can lead to decay and make the paper unusable for recycling. Furthermore, when the laminated paper is subjected to a maceration process for recycling, the resin layer or the like prevents water from penetrating into the paper base layer, which tends to reduce maceration properties. In contrast, the bale manufacturing method of this embodiment includes a washing step in which the waste paper is washed with wash water containing an oxidizing agent, thereby removing bacteria that cause decay and also removing proteins that serve as a nutrient source for bacteria that promote bale decay. As a result, it is thought that the growth of bacteria in the waste paper during bale storage is suppressed, improving the decay resistance of the bale. Furthermore, the median area of ​​recycled paper is 20 cm 2 As a result, adequate gaps are formed between the wastepaper in the bale, allowing adequate air to pass through the bale and allowing the wastepaper to dry appropriately, which is thought to inhibit the growth of bacteria that cause decay and improve the decay resistance of the bale. 2 If the temperature is below this level, it is believed that water will sufficiently penetrate into the waste paper when the paper is subjected to a defibration step for recycling, thereby improving the defibration properties.

[0009] The basis weight of the waste paper is set at 100 g / m² to improve the disintegration of the waste paper contained in the bale. 2 or more, and preferably 120 g / m 2 More than 600g / m 2 or less, more preferably 140 g / m 2 More than 500g / m 2 or less, more preferably 160 g / m 2 More than 400g / m 2 or less, even more preferably 180 g / m 2 More than 300g / m 2 The following is the result. The basis weight of the waste paper is measured by the method described in the examples.

[0010] The median area of ​​the waste paper is set at 20cm2 from the viewpoint of reducing the number of bacteria attached to the waste paper contained in the bale and improving the disintegration property of the waste paper contained in the bale. 2 More than 150cm 2 less than 50cm, preferably 2 More than 120cm 2 Less than 70cm, preferably 2 More than 100cm 2 The following is the result. The median area of ​​the waste paper is measured by the method described in the Examples.

[0011] (recycled paper) In this embodiment, the waste paper has at least a resin layer and a paper base layer. [Resin layer] The resin constituting the resin layer in recycled paper is not particularly limited, but examples include polyolefins such as high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polypropylene (PP), polyesters such as polyethylene terephthalate (PET), polyamides such as ethylene-vinyl alcohol copolymer (EVOH), nylon, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), styrene-acrylic copolymer, and ethylene-α-olefin copolymer. Furthermore, when recycled paper has multiple resin layers, the resins constituting each resin layer may be the same or different. Among these, from the viewpoint of recyclability, the resin constituting the resin layer is preferably one or more selected from polyolefin, ethylene-vinyl alcohol copolymer (EVOH), and ethylene-methyl methacrylate copolymer (EMMA), more preferably one or more selected from low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-methyl methacrylate copolymer (EMMA), and even more preferably one or more selected from low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE).

[0012] The basis weight of the resin layer in the waste paper is preferably 5 g / m from the viewpoint of improving the disintegration property of the waste paper contained in the bale. 2 More than 120g / m 2 Less than 10 g / m, more preferably 2 More than 100g / m 2 or less, more preferably 15 g / m 2 More than 80g / m 2 More preferably, 20 g / m or less 2 More than 60g / m 2 When the waste paper has a plurality of resin layers, the basis weight of the resin layers in the waste paper indicates the total basis weight of the respective resin layers.

[0013] From the viewpoint of improving the disintegration property of the waste paper contained in the bale, the thickness of the resin layer in the waste paper is preferably 5 μm to 130 μm, more preferably 10 μm to 110 μm, even more preferably 15 μm to 90 μm, and even more preferably 20 μm to 70 μm. Note that when the waste paper has multiple resin layers, the thickness of the resin layer in the waste paper refers to the total thickness of the respective resin layers.

[0014] [Paper base layer] The paper base layer is not particularly limited as long as it is a commonly used paper containing plant-derived wood pulp as a main component. Examples of wood pulp include, but are not limited to, chemical pulps such as hardwood kraft pulp (LKP), softwood kraft pulp (NKP), sulfite pulp (SP), dissolving pulp (DP), soda pulp (AP), bleached kraft pulp (BKP), unbleached kraft pulp (UKP), and oxygen-bleached kraft pulp (OKP), semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-groundwood pulp (CGP), and mechanical pulps such as groundwood pulp (GP), thermomechanical pulp (TMP), and chemi-thermomechanical pulp (CTMP). Among these, from the viewpoint of recyclability, the paper base layer preferably contains one or more selected from hardwood kraft pulp and softwood kraft pulp, more preferably one or more selected from hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), softwood unbleached kraft pulp (NUKP) and softwood bleached kraft pulp (NBKP), and even more preferably one or more selected from hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP).

[0015] The paper substrate layer may also have a pigment coating layer. The pigment coating layer may be one layer or two or more layers. The pigment coating layer preferably contains a pigment and a binder. Examples of pigments include, but are not limited to, heavy calcium carbonate, kaolin, and plastic pigments. Examples of binders include, but are not limited to, starch, styrene-acrylic copolymer latex, styrene-butadiene copolymer latex, and olefin-carboxylic acid emulsion copolymer latex.

[0016] The basis weight of the paper base layer in the waste paper is preferably 80 g / m from the viewpoint of improving the disintegration property of the waste paper contained in the bale. 2 More than 400g / m 2 or less, more preferably 100 g / m 2 More than 350g / m 2 or less, more preferably 120 g / m 2 More than 300g / m 2 or less, even more preferably 150 g / m 2 More than 250g / m 2 The following is the result. When the waste paper has a plurality of paper base layers, the basis weight of the paper base layers in the waste paper indicates the total basis weight of the respective paper base layers.

[0017] From the viewpoint of improving the disintegration properties of the waste paper contained in the bale, the thickness of the paper base layer in the waste paper is preferably 100 μm or more and 600 μm or less, more preferably 120 μm or more and 550 μm or less, even more preferably 150 μm or more and 500 μm or less, and even more preferably 200 μm or more and 450 μm or less. When the waste paper has a plurality of paper base layers, the thickness of the paper base layer in the waste paper refers to the total thickness of the respective paper base layers.

[0018] In this embodiment, the content of sizing agent in the paper base layer of the recycled paper is preferably 0.2% by mass or more and 2.1% by mass or less, more preferably 0.4% by mass or more and 1.8% by mass or less, even more preferably 0.6% by mass or more and 1.6% by mass or less, and even more preferably 0.8% by mass or more and 1.4% by mass or less. When the sizing agent content in the paper base layer of the wastepaper is 0.2% by mass or more, the moisture remaining in the wastepaper contained in the bale, such as when the wastepaper is washed before bale formation, is reduced, further reducing the number of bacteria adhering to the wastepaper contained in the bale and further improving putrefaction resistance.Furthermore, when the sizing agent content in the paper base layer of the wastepaper is 2.1% by mass or less, sufficient water can easily penetrate into the wastepaper during the disintegration process when the bale is recycled, further improving the disintegration properties of the wastepaper contained in the bale. The content of the sizing agent in the paper base layer of the recycled paper is measured by the method described in the Examples.

[0019] In this embodiment, examples of the sizing agent in the paper base layer of the recycled paper include rosin sizing agents, synthetic sizing agents, and petroleum resin-based sizing agents.

[0020] In this embodiment, the total content of dry strength agent and wet strength agent in the paper base layer of the waste paper is preferably 0.05% by mass or more and 2.00% by mass or less, more preferably 0.10% by mass or more and 1.50% by mass or less, and even more preferably 0.12% by mass or more and 1.20% by mass or less, from the viewpoint of reducing the number of bacteria attached to the waste paper contained in the bale and improving the disintegrability of the waste paper contained in the bale.

[0021] In this embodiment, the content of the dry paper strength agent in the paper base layer of the waste paper is preferably 0.50% by mass or more and 2.00% by mass or less, more preferably 0.65% by mass or more and 1.60% by mass or less, and even more preferably 0.80% by mass or more and 1.20% by mass or less, from the viewpoints of reducing the number of bacteria attached to the waste paper contained in the bale, improving the decay resistance of the bale, and improving the disintegration properties of the waste paper contained in the bale. In addition, in this embodiment, the content of the wet strength agent in the paper base layer of the waste paper is preferably 0.05% by mass or more and 0.25% by mass or less, more preferably 0.07% by mass or more and 0.20% by mass or less, and even more preferably 0.10% by mass or more and 0.15% by mass or less, from the viewpoints of reducing the number of bacteria attached to the waste paper contained in the bale, improving the putrefaction resistance of the bale, and improving the disintegration properties of the waste paper contained in the bale. The content of the paper strength agent in the paper base layer of the recycled paper is measured by the method described in the Examples.

[0022] In this embodiment, the paper strength agents in the paper base layer of the recycled paper include dry strength agents and wet strength agents. Examples of dry strength agents include polyacrylamide, cationized starch, and carboxymethyl cellulose. Examples of wet strength agents include polyamide polyamine epichlorohydrin, polyamide epichlorohydrin, urea formaldehyde resin, and melamine formaldehyde resin.

[0023] In this embodiment, the recycled paper may have other layers in addition to the resin layer and the paper substrate layer, such as a metal layer, a printed layer, and an adhesive layer.

[0024] [Metal layer] In this embodiment, the waste paper may further have a metal layer. In this embodiment, the metal layer of the waste paper preferably contains aluminum. Furthermore, in this embodiment, the metal layer of the waste paper is more preferably aluminum foil.

[0025] When the waste paper contains a metal layer, the basis weight of the metal layer in the waste paper is preferably 8 g / m from the viewpoint of suppressing the metal layer from being pulverized during the waste paper pulverization process and improving the pulverization properties of the waste paper contained in the bale. 2 More than 30g / m 2 Less than 10 g / m, more preferably 2 More than 27g / m 2 or less, more preferably 12 g / m 2 More than 24g / m 2 or less, even more preferably 14 g / m 2 More than 22g / m 2 The following is the result. When the waste paper has a plurality of metal layers, the basis weight of the metal layers in the waste paper refers to the basis weight of each metal layer.

[0026] When the waste paper contains a metal layer, the thickness of the metal layer in the waste paper is preferably 1 μm or more and 50 μm or less, more preferably 3 μm or more and 40 μm or less, even more preferably 5 μm or more and 30 μm or less, and even more preferably 6 μm or more and 20 μm or less. In addition, when waste paper has a plurality of metal layers, the thickness of the metal layers in the waste paper refers to the thickness of each metal layer. When the thickness of the metal layer is 1 μm or more, the metal layer is prevented from becoming too fine during the defibration process of the waste paper when the bale is recycled, making the defibration process more efficient. Also, when the thickness of the metal layer is 50 μm or less, the penetration of moisture into the waste paper contained in the bale is less likely to be hindered, further improving the defibration properties of the waste paper.

[0027] [Printing layer] In this embodiment, the waste paper may further have a printed layer. An example of the printed layer is a printed layer provided on a paper substrate layer. The printed layer may be formed using a known ink such as an oil-based ink, a water-based ink, or a biomass ink. The printed content may be a pattern, a design, or information (ingredients, expiration date, QR Code (registered trademark), etc.). The printed layer may be formed on the entire surface or on a part of the layer to which the printed layer is applied.

[0028] [Adhesive layer] In this embodiment, the waste paper may further have an adhesive layer, which is formed mainly to adhere the metal layer to the paper base layer when the waste paper has a metal layer, and / or to adhere the metal layer to the resin layer. Examples of resins that may be used to form the adhesive layer include ethylene-methacrylic acid copolymer resin (EMAA), ethylene-acrylic acid copolymer resin (EAA), ethylene-vinyl acetate copolymer resin (EVA), ethylene-ethyl acrylate copolymer resin (EEA), and ethylene-butyl acrylate copolymer resin (EBA).

[0029] (Favorable physical properties of recycled paper) In this embodiment, the median density of the recycled paper is preferably 0.70 g / cm 3 More preferably, it is 0.73 g / cm or more. 3 More than 1.00g / cm 3 or less, more preferably 0.76 g / cm 3 More than 0.90g / cm 3 The following is the result. The median density of recycled paper is 0.70 g / cm 3 If the median density of the waste paper is within the above-mentioned upper limit range, sufficient water can easily penetrate into the waste paper contained in the bale during the disintegration process when the bale is recycled, thereby further improving the disintegration properties of the waste paper contained in the bale. The density of the waste paper can be adjusted by the press line pressure during dewatering when making the paper base layer of the waste paper.

[0030] In this embodiment, the 24-hour water absorbency of the waste paper is preferably 25% or more and 85% or less, more preferably 30% or more and 80% or less, even more preferably 40% or more and 75% or less, and even more preferably 50% or more and 65% or less. When the 24-hour water absorbency of wastepaper is 25% or higher, sufficient water can easily penetrate into the wastepaper contained in the bale during the disintegration process when the bale is recycled, improving the disintegration of the wastepaper contained in the bale. Furthermore, when the 24-hour water absorbency of wastepaper is 85% or lower, the amount of moisture remaining in the wastepaper contained in the bale, such as when the wastepaper is washed before bale formation, is reduced, further reducing the number of bacteria adhering to the wastepaper contained in the bale and further improving the decay resistance of the bale. The 24-hour water absorbency of waste paper is adjusted, for example, by the content of sizing agent in the paper base layer of the waste paper. The 24-hour water absorbency of waste paper is determined from the rate of increase in the mass of the waste paper when the waste paper is immersed in water for 24 hours, specifically by the method described in the examples.

[0031] Examples of the waste paper include waste paper derived from food and beverage containers, paper bags, and paper cutlery. Examples of food and beverage containers include liquid containers and food containers, more specifically paper trays, aseptic containers, paper cups, milk cartons, etc. Among these, the waste paper is preferably at least one type selected from waste paper for aseptic containers and waste paper for paper cups. The recycled paper for aseptic containers has, for example, the following structures (a1) to (a2). In the structures below, the layer on the right indicates the layer that was in contact with the contents when used as an aseptic container. In the structures below, the "(printed layer)" and "(adhesive layer)" are optional layers that may or may not be present as necessary. In the structures below, the paper base layer may have the above-mentioned pigment coating layer, and a printed layer may be provided on the pigment coating layer. In the structures below, the "resin layer" may be one layer or two or more layers. (a1): Resin layer / (printing layer) / paper base layer / resin layer / metal layer / (adhesive layer) / resin layer (a2): Resin layer / (printing layer) / paper base layer / resin layer / resin layer (barrier layer) / (adhesive layer) / resin layer

[0032] Preferably, recycled paper for paper cups has the following structures (b1) to (b5), for example. In the structures below, the layer on the right indicates the layer that was in contact with the contents when used as a paper cup. In the structures below, the "(printed layer)" and "(adhesive layer)" are optional layers that may or may not be present as needed. In the structures below, the paper base layer may have the above-mentioned pigment coating layer, and a printed layer may be provided on the pigment coating layer. In the structures below, the "resin layer" may be one layer or two or more layers. (b1): (printing layer) / paper base layer / resin layer / (adhesive layer) / metal layer / (adhesive layer) / resin layer (b2): (printing layer) / paper base layer / resin layer / (adhesive layer) / resin layer (b3): ​​Resin layer / (Printing layer) / Paper base layer / Resin layer (b4): (printing layer) / resin layer / paper base layer / resin layer (b5): (printing layer) / paper base layer / resin layer

[0033] (Cleaning process) In this embodiment, the washing process is a process in which the above-mentioned waste paper is washed with a washing solution containing an oxidizing agent. By washing the waste paper with a washing solution containing an oxidizing agent, bacteria that cause decay are removed, and further, proteins that serve as a nutrient source for bacteria that promote decay of the bale are also removed. As a result, the growth of bacteria attached to the waste paper during bale storage is suppressed, and the decay resistance of the bale is improved.

[0034] The content of the oxidizing agent in the cleaning solution is preferably 0.0001% by mass (1 ppm by mass) to 5% by mass, more preferably 0.0002% by mass (2 ppm by mass) to 4.5% by mass, even more preferably 0.0003% by mass (3 ppm by mass) to 4% by mass, and still more preferably 0.0004% by mass (4 ppm by mass) to 3.5% by mass, from the viewpoints of reducing the number of bacteria adhering to the waste paper contained in the bale, improving the decay resistance of the bale, and maintaining the integrity of processing equipment such as the cleaning equipment.

[0035] In the washing step, the oxidizing agent contained in the washing water is preferably one or more selected from hydrogen peroxide, ozone, and sodium hypochlorite, from the viewpoints of reducing the number of bacteria attached to the waste paper contained in the bale and improving the decay resistance of the bale, and hydrogen peroxide is more preferred. When the oxidizing agent contained in the cleaning water is hydrogen peroxide, the content of hydrogen peroxide in the cleaning solution is preferably 1% by mass or more and 5% by mass or less, more preferably 1.5% by mass or more and 4.5% by mass or less, even more preferably 2% by mass or more and 4% by mass or less, and still more preferably 2.5% by mass or more and 3.5% by mass or less, from the viewpoints of reducing the number of bacteria attached to the waste paper contained in the bale, improving the decay resistance of the bale, and maintaining the integrity of processing equipment such as the cleaning equipment. When the oxidizing agent contained in the cleaning water is sodium hypochlorite, the content of sodium hypochlorite in the cleaning solution is preferably 0.005% by mass (50 ppm by mass) to 0.05% by mass (500 ppm by mass), more preferably 0.01% by mass (100 ppm by mass) to 0.04% by mass (400 ppm by mass), even more preferably 0.015% by mass (150 ppm by mass) to 0.035% by mass (350 ppm by mass), and still more preferably 0.02% by mass (200 ppm by mass) to 0.03% by mass (300 ppm by mass), from the viewpoints of reducing the number of bacteria adhering to the waste paper contained in the bale, improving the decay resistance of the bale, and maintaining the cleaning equipment and other processing equipment. When the oxidizing agent contained in the cleaning water is ozone, the content of ozone in the cleaning water is, from the viewpoint of reducing the number of bacteria adhering to the waste paper contained in the bale and improving the decay resistance of the bale, preferably from 0.0001% by mass (1 ppm by mass) to 0.002% by mass (20 ppm by mass), more preferably from 0.0002% by mass (2 ppm by mass) to 0.0015% by mass (15 ppm by mass), even more preferably from 0.0003% by mass (3 ppm by mass) to 0.001% by mass (10 ppm by mass), and still more preferably from 0.0004% by mass (4 ppm by mass) to 0.0008% by mass (8 ppm by mass).

[0036] The washing step may be carried out before the crushing step described below, or after the crushing step described below, or the crushing step and washing step may be carried out simultaneously. Among these, from the viewpoint of washing efficiency, it is preferable to carry out the washing step after the crushing step and before the molding step, or to carry out the crushing step and washing step simultaneously, and it is more preferable to carry out the crushing step and washing step simultaneously. Any known device can be used in the washing step. When the crushing step and the washing step are carried out simultaneously, it is preferable to use a crushing / washing machine or the like.

[0037] (Crushing process) In this embodiment, it is preferable to have a crushing step of crushing the waste paper before the molding step. By having the crushing step, the waste paper to be subjected to the molding step is made uniform in size, so that when the bale is recycled, for example, the disintegration process becomes more efficient and the disintegration property of the waste paper contained in the bale is further improved. As the crusher used in the crushing step, it is preferable to use a single-shaft crusher, a twin-shaft crusher, etc., depending on the size of the waste paper after crushing. In addition, when the crushing step is carried out and the above-mentioned washing step is carried out at the same time, it is preferable to use a crushing and washing machine, etc.

[0038] (molding process) The bale manufacturing method of this embodiment includes a molding step of compressing and molding waste paper having at least a resin layer and a paper base layer to obtain a bale. As the bale molding device in the molding step, a known bale molding device may be used as appropriate.

[0039] In the forming step, the bale forming pressure is preferably 500 kN / m 2 More than 2500kN / m 2 Less than or equal to 750 kN / m 2 More than 2250kN / m 2 or less, more preferably 1000 kN / m 2 More than 2000kN / m 2 The following is the result. By keeping the bale forming pressure within the above range, the density of the bale falls within the desired bale density range described below, which further reduces the number of bacteria adhering to the waste paper contained in the bale, further improves the putrefaction resistance of the bale, and further improves the disintegration properties of the waste paper contained in the bale.

[0040] [Veil] In this embodiment, the bale can be obtained by the bale manufacturing method described above. Therefore, the bale in this embodiment has a reduced number of bacteria attached to the waste paper contained in the bale, and also has excellent disintegration properties for the waste paper contained in the bale.

[0041] In this embodiment, the waste paper contained in the bale is stored for 7 days. 2 The number of bacteria adhering to the surface per unit area should preferably be 10 CFU / cm 2 less than 8 CFU / cm 2 less than 5 CFU / cm 2 less than, even more preferably less than 1 CFU / cm 2 The lower limit is not particularly limited, but is preferably 0.01 CFU / cm 2 It may be more than that. More specifically, after storing the bale under conditions of a temperature of 30°C and a humidity of 70% RH for 7 days, the waste paper collected from the bale was 2 The number of bacteria adhering to the surface per unit area should preferably be 10 CFU / cm 2 less than 8 CFU / cm 2 less than 5 CFU / cm 2 less than, even more preferably less than 1 CFU / cm 2 The lower limit is not particularly limited, but is preferably 0.01 CFU / cm 2 It may be more than that. 1cm of waste paper in a bale after 7 days of storage 2 When the number of bacteria adhering to the surface of the bale is within the above range, bacterial decay of the bale and the accompanying generation of unpleasant odors are suppressed, thereby improving the decay resistance of the bale and further improving its recyclability. 1cm of waste paper in a bale after 7 days of storage 2 The number of bacteria adhering to the surface per unit area can be measured by the method described in the Examples.

[0042] In this embodiment, the density of the bale is preferably 0.3 t / m 3 More than 1.0t / m 3 Less than 0.4t / m, preferably 0.4t / m 3 More than 0.8t / m 3 or less, more preferably 0.5 t / m 3 More than 0.7t / m 3 The following is the result. Bale density is 0.3t / m 3 If the density of the bale is 1.0 t / m or more, the waste paper inside the bale will be in close contact with each other, making the bale less likely to crumble and improving the handling of the bale. 3 At this level, the waste paper is not compressed more than necessary within the bale, making it easier to loosen the bale when it is recycled, and improving disintegration properties. Also, adequate gaps are created between the waste paper sheets within the bale, allowing moisture to escape more easily, further reducing the number of bacteria adhering to the waste paper contained in the bale. Since spoilage of the bale due to bacterial growth and the accompanying generation of foul odors are suppressed, the spoilage resistance of the bale is further improved, and recyclability is further improved.

[0043] In this embodiment, the bale is made from the above-mentioned waste paper. Furthermore, the composition and other physical properties of the waste paper do not change before and after bale formation. In other words, in this embodiment, the form of the waste paper contained in the bale is the same as the waste paper exemplified in the above-mentioned bale manufacturing method. The bale in this embodiment may contain waste paper other than the above waste paper, as long as the effects of the present invention are not impaired. The bale in this embodiment may also contain foreign matter other than the above waste paper, as long as the effects of the present invention are not impaired. Examples of foreign matter include straws, caps for food and beverage containers, and lids for food and beverage containers. In this embodiment, the content of the above waste paper in the bale is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0044] (Application) Because the bale of this embodiment has the above-mentioned characteristics, it can be preferably used for recycling waste paper and can be suitably used as a raw material for waste paper pulp. Waste paper pulp made from the bale of this embodiment is preferably used as a raw material for various types of paper. The type of paper to be made is not particularly limited, and examples include printing paper, packaging paper, sanitary paper, and cardboard. The made paper can also be processed to manufacture packaging containers (e.g., tissue boxes, paper cup sleeves, etc.). Furthermore, the bale of this embodiment can be used to recover resin components derived from the resin layer and metal components derived from the metal layer contained in the waste paper, and these can be recycled. [Example]

[0045] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In the examples and comparative examples, "parts" and "%" refer to "parts by mass" and "% by mass," respectively, unless otherwise specified. Furthermore, the operations in the examples and comparative examples were carried out under conditions of 23±1°C and 50±2% RH, unless otherwise specified.

[0046] [Bale manufacturing method] Example 1 (recycled paper) The waste paper used was aseptic packaging waste paper collected after using the paper of Composition 1 in Table 1 as a paper container for beverages. The contents of the paper containers when used as beverage containers included milk, soy milk, and fruit juices. The paper base layer of the recycled paper of Example 1, Structure 1, was obtained from a paper stock (pulp slurry) containing 100 parts by mass of raw pulp (pulp composition (mass ratio): softwood bleached kraft pulp (NBKP) / hardwood bleached kraft pulp (LBKP) = 40 / 60, redisintegrated freeness (CSF): 550 mL), 1.0 part by mass of a rosin sizing agent (Sizepine N-881, manufactured by Arakawa Chemical Industries, Ltd.), 1.0 part by mass of a polyacrylamide-based dry strength agent (PS117, manufactured by Arakawa Chemical Industries, Ltd.), and 1.0 part by mass of aluminum sulfate. The linear press pressure during dewatering when making the paper base layer was 800 kN / m. (Crushing process / washing process) The waste paper was placed in a shredding and washing machine (A-tech Corporation, paper container recycling machine PPRS), shredded with blades having six hooks, and washed with washing water (hydrogen peroxide solution, concentration: 3% by mass, fresh water consumption: 24 L / min). (Bale forming process) Approximately 60 kg of waste paper was placed in a bale compressor (YB-32M-PA-10, manufactured by Yuken Kogyo Co., Ltd., bale size: 640 x 430 x 350 mm) and the bale was formed under a pressure of 1800 kN / m 2 The mixture was compressed at a bale forming pressure of 1000 kJ / g to obtain a bale.

[0047] <Example 2> The number of blade hooks in the crushing process was set to 3, and the bale forming pressure in the bale forming process was set to 1900 kN / m 2 A veil was obtained in the same manner as in Example 1, except that:

[0048] Example 3 The number of blade hooks in the crushing process was set to 9, and the bale forming pressure in the bale forming process was set to 1700 kN / m 2 A veil was obtained in the same manner as in Example 1, except that:

[0049] Example 4 Bales were obtained in the same manner as in Example 1, except that the washing water in the washing step was changed to ozone water (concentration: 5 mass ppm).

[0050] <Example 5> Bales were obtained in the same manner as in Example 1, except that the washing water in the washing step was changed to an aqueous sodium hypochlorite solution (concentration: 200 mass ppm).

[0051] Example 6 Bales were obtained in the same manner as in Example 1, except that the recycled paper used was the recycled paper of Configuration 1, which was obtained by setting the press line pressure during dewatering when making the paper base layer at 750 kN / m.

[0052] Example 7 Bales were obtained in the same manner as in Example 1, except that the recycled paper used was the recycled paper of Configuration 1, which was obtained by setting the press line pressure during dewatering when making the paper base layer at 850 kN / m.

[0053] Example 8 Bales were obtained in the same manner as in Example 1, except that the waste paper used was waste paper of Configuration 1, in which the amount of sizing agent added to the paper stock (pulp slurry) when producing the paper base layer was 0.5 parts by mass per 100 parts by mass of raw pulp.

[0054] Example 9 Bales were obtained in the same manner as in Example 1, except that the waste paper used was waste paper of Configuration 1, in which the amount of sizing agent added to the paper stock (pulp slurry) when producing the paper base layer was 0.8 parts by mass per 100 parts by mass of raw pulp.

[0055] Example 10 Bales were obtained in the same manner as in Example 1, except that the waste paper used was waste paper of Configuration 1, in which the amount of sizing agent added to the paper stock (pulp slurry) when producing the paper base layer was 1.2 parts by mass per 100 parts by mass of raw pulp.

[0056] Example 11 Bales were obtained in the same manner as in Example 1, except that the waste paper used was waste paper of Configuration 1, in which the amount of sizing agent added to the paper stock (pulp slurry) when producing the paper base layer was 1.5 parts by mass per 100 parts by mass of raw pulp.

[0057] Example 12 The bale forming pressure during the bale forming process is 1400kN / m 2 A veil was obtained in the same manner as in Example 1, except that:

[0058] Example 13 The bale forming pressure during the bale forming process is 2200kN / m 2 A veil was obtained in the same manner as in Example 1, except that:

[0059] Example 14 Bales were obtained in the same manner as in Example 1, except that the waste paper used was waste paper (recycled paper cups) collected after using the paper of Configuration 2 in Table 1 as paper containers for beverages. The contents when used as paper containers for beverages included iced coffee, soft drinks, ice cream, etc. The paper base layer of the recycled paper of Example 14, Structure 2, was prepared from a pulp slurry containing 100 parts by mass of raw pulp (pulp composition (mass ratio): softwood bleached kraft pulp (NBKP) / hardwood bleached kraft pulp (LBKP) = 40 / 60, redisintegrated freeness (CSF): 440 mL), 1.0 part by mass of rosin sizing agent (Sizepine N-881, manufactured by Arakawa Chemical Industries, Ltd.), 1.0 part by mass of polyacrylamide-based strength agent (PS117, manufactured by Arakawa Chemical Industries, Ltd.), 0.15 part by mass of polyamide epichlorohydrin (WS4024, wet strength agent, manufactured by Seiko PMC Corporation), and 1.0 part by mass of aluminum sulfate. The linear press pressure during dewatering for the paper base layer was 700 kN / m.

[0060] Example 15 Bales were obtained in the same manner as in Example 1, except that the waste paper used was waste paper (recycled paper cups) collected after using the paper of Configuration 3 in Table 1 as paper containers for beverages. The contents when used as paper containers for beverages included hot coffee, cocoa, green tea, and corn soup. The paper base layer of the recycled paper of Example 15, Structure 3, was obtained from a pulp slurry containing 100 parts by mass of raw pulp (pulp composition (mass ratio): softwood bleached kraft pulp (NBKP) / hardwood bleached kraft pulp (LBKP) = 40 / 60, redisintegrated freeness (CSF): 440 mL), 1.0 part by mass of rosin sizing agent (Sizepine N-881, manufactured by Arakawa Chemical Industries, Ltd.), 1.0 part by mass of polyacrylamide-based strength agent (PS117, manufactured by Arakawa Chemical Industries, Ltd.), 0.15 part by mass of polyamide epichlorohydrin (WS4024, wet strength agent, manufactured by Seiko PMC Corporation), and 1.0 part by mass of aluminum sulfate. The linear press pressure during dewatering when making the paper base layer was 700 kN / m.

[0061] <Comparative Example 1> The washing process was not carried out (the crushing process was carried out), and the bale forming pressure in the bale forming process was 1900 kN / m 2 A veil was obtained in the same manner as in Example 1, except that:

[0062] <Comparative Example 2> Bales were obtained in the same manner as in Example 1, except that the washing water in the washing step was changed to water (without the addition of an oxidizing agent or the like).

[0063] <Comparative Example 3> The crushing process was not carried out (the washing process was carried out), and the bale forming pressure in the bale forming process was 1900 kN / m 2 A veil was obtained in the same manner as in Example 1, except that:

[0064] <Comparative Example 4> The number of blade hooks in the crushing process was set to 12, and the bale forming pressure in the bale forming process was set to 1700 kN / m 2 A veil was obtained in the same manner as in Example 1, except that

[0065] <Comparative Example 5> Bales were obtained in the same manner as in Example 1, except that the washing water in the washing step was changed to an aqueous sodium hydroxide solution (concentration: 5 ppm by mass, pH: 9.0).

[0066] <Comparative Example 6> Bales were obtained in the same manner as in Example 1, except that the washing water in the washing step was changed to an aqueous hypochlorous acid solution (effective chlorine concentration: 50 mass ppm).

[0067] Table 1 shows the composition of the waste paper used in the examples and comparative examples.

[0068] [Table 1]

[0069] [Evaluation and measurement methods] <Median area of ​​recycled paper> Approximately 100 g of waste paper was randomly collected from the bales of the Examples and Comparative Examples, and was passed through a sieve (φ: 20 mm) to remove small amounts of waste paper. The remaining waste paper was scanned using an Epson Scan to obtain images. The scanned images were analyzed using ImageJ, and the area of ​​each waste paper was obtained to calculate the median area. The median area refers to the value that is located in the middle when the area values ​​of the obtained waste paper are arranged in ascending order.

[0070] <Median density of recycled paper> Waste paper randomly sampled from the bales of the Examples and Comparative Examples was dried completely and then conditioned for 96 hours in a humidity-controlled environment as specified in JIS P 8111: 1998. Approximately 100 g of the conditioned waste paper was passed through a sieve (φ: 20 mm) to remove small amounts of waste paper, and the density of the remaining waste paper was measured in accordance with JIS P 8118: 2014 to calculate the median density of the waste paper. The median density value refers to the value that is in the middle when the density values ​​of the obtained waste paper are arranged in ascending order.

[0071] <Water absorption over 24 hours> Randomly sampled wastepaper from the bales of the Examples and Comparative Examples was dried and then conditioned for 96 hours in a humidity-controlled environment according to JIS P 8111:1998. Approximately 10 g of the conditioned wastepaper was immersed in 1 L of water (water temperature: 23±1°C) for 24 hours, after which the wastepaper was collected. Each sheet of collected wastepaper was placed between absorbent paper (Advantec, No. 26, 190 mm x 190 mm) and then rolled back and forth without pressure between metal rollers (18 cm wide, 10 cm diameter, 10 kg). Excess water was removed, and this was designated the wastepaper after water immersion. The mass of the wastepaper before and after immersion was measured (to the nearest 1 mg), and the water absorbency was calculated using the following formula. This was the 24-hour water absorbency of the wastepaper. [Water absorption (%)] = ([Mass of waste paper after immersion in water (g)] - [Mass of waste paper before immersion in water (g)]) / [Mass of waste paper before immersion in water (g)] × 100

[0072] <Sizing agent dry strength agent content and wet strength agent content> Randomly collected waste paper from the bales of the Examples and Comparative Examples was dried. After drying, layers other than the paper base layer, such as the resin layer, were removed by grinding using a grinding machine (manufactured by Sagawa Corporation, grinding wheel dimensions φ50.8 × 12.7 mm) while checking the layer boundaries under a microscope, and the paper base layer was recovered. The contents of sizing agent, dry strength agent and wet strength agent in the recovered paper base layer were each quantified using pyrolysis gas chromatography (GCMS) under the following measurement conditions. (Measurement conditions for sizing agent content) ·Pyrolysis furnace temperature: 450℃ Measurement temperature conditions: 100 to 325°C, temperature increased at 15°C / min Column used: HP-5MS (Agilent Technologies) Calibration curve: A calibration curve was created using a rosin sizing agent (Sizepine N-881, manufactured by Arakawa Chemical Industries, Ltd.) of known concentration as a standard. (Measurement conditions for dry paper strength agent content) ·Pyrolysis furnace temperature: 500℃ Measurement temperature conditions: 40 to 270°C, temperature increased at 10°C / min Column used: HP-INNOWax (Agilent Technologies) Calibration curve: A calibration curve was created using polyacrylamide (PS117, dry paper strength agent, manufactured by Arakawa Chemical Industries, Ltd.) of known concentration as a standard. (Wet strength agent content measurement conditions) ·Pyrolysis furnace temperature: 500℃ Measurement temperature conditions: 40 to 270°C, temperature increased at 10°C / min Column used: HP-INNOWax (Agilent Technologies) Calibration curve: A calibration curve was created using polyamide epichlorohydrin (WS4024, wet strength agent, manufactured by Seiko PMC Corporation) of known concentration as a standard.

[0073] <Bale density> The bale density was calculated from the weight of the waste paper added during the bale forming process and the volume of the resulting bale.

[0074] <1cm of waste paper after 7 days of storage 2 Number of bacteria attached to each surface> The bales of the examples and comparative examples were wrapped around the sides only with five PP bands (manufactured by Moriya Sangyo Co., Ltd., model number: 12 J-S1) at equal intervals using a cordless handy packing machine (manufactured by Strapak Co., Ltd., STB73, tightening strength 900N), and stored for 7 days under conditions of a temperature of 30°C and a humidity of 70% RH. After the storage, 3 cm square pieces (9 cm 2 Waste paper large enough to make a square sample was collected. A swab test kit (Wipe Check TE-302, manufactured by Sato Chemical Industry Co., Ltd.) was used to wipe a 3 cm square area on both sides of the waste paper to collect a sample. 1 mL of the obtained sample was applied to a general viable bacterial drop test medium (MC-Media Pad, manufactured by JNC Corporation) and cultured in an incubator at 35°C for 48 hours, after which the number of colonies formed was counted. The number of counted colonies was multiplied by the size (area) of the waste paper at the time of sample collection (9 cm 2 ) and divide by 1cm of waste paper for each sample.2 Colony count per surface (CFU / cm 2 The number of colonies (CFU / cm) obtained from 10 sheets of used paper was calculated. 2 ) was calculated by dividing the average value of 1 cm of waste paper in each example and comparative example. 2 of bacteria per surface (CFU / cm 2 ) and evaluated according to the following evaluation criteria. (Evaluation criteria) A: The number of bacteria is 1 CFU / cm 2 less than B: The number of bacteria is 1 CFU / cm 2 More than 5 CFU / cm 2 less than C: The number of bacteria is 5 CFU / cm 2 More than 10CFU / cm 2 less than D: The number of bacteria is 10 CFU / cm 2 End

[0075] <Rot resistance> The bales of the examples and comparative examples were wrapped around the sides only with five PP bands (manufactured by Moriya Sangyo Co., Ltd., model number: 12 J-S1) at equal intervals using a cordless handy packaging machine (manufactured by Strapak Co., Ltd., STB73, tightening strength 900N), and then stored for 7 days under conditions of a temperature of 30°C and a humidity of 70% RH. The odor was then evaluated by sensory evaluation and scored based on the "odor score" below. The odor evaluation was carried out by panelists who passed a panel selection test using five standard odor liquids by odor evaluators. The evaluation results of the 10 panelists were averaged and the spoilage resistance was evaluated according to the following evaluation criteria. The smaller the average score, the less odor there was and the better the spoilage resistance. (Odor score) 0 points: No smell of sulfur compounds 1 point: A slight smell of sulfur compounds is detected 2 points: Smell of sulfur compounds detected 3 points: Strong smell of sulfur compounds detected (Evaluation criteria for decay resistance) A: The average score of the panelists is between 0 and 0.5 points. B: The average score of the panelists is 0.5 points or more but less than 1.0 points C: The average score of the panelists is 1.0 or more and less than 1.5 points. D: The average score of the panelists is 1.5 points or more.

[0076] <Disintegrability> From the bales of the Examples and Comparative Examples, 60 g of waste paper (on an absolute dry basis) was collected and disintegrated for 15 minutes using a disintegrator (Kumagaya Riki Kogyo Co., Ltd., No. 2532) to obtain a pulp slurry with a solid concentration of 3% by mass. The resulting pulp slurry was then fed into a flat screen (Kumagaya Riki Kogyo Co., Ltd., No. 230703, slit: 6 cuts) at a flow rate of 10 L / min for 15 minutes. The residue rate was calculated from the absolute dry mass of the residue that did not pass through the flat screen, and the fiber recovery rate was calculated using the following formula, which was used as an index of disintegration performance. Fiber recovery rate (%) = {1 - ([residue rate (%)] / 100)} / Ratio of the basis weight of the paper base layer to the basis weight of the recovered paper × 100 Residue rate (%) = [bone dry mass (g) of residue that did not pass through the flat screen] / [mass (g) of solids in the pulp slurry introduced into the flat screen] × 100 (Evaluation results) A: Fiber recovery rate is 90% or more B: Fiber recovery rate is 70% or more but less than 90% C: Fiber recovery rate is 50% or more but less than 70% D: Fiber recovery rate is less than 50%

[0077] Table 2 shows the measurement and evaluation results for the examples and comparative examples.

[0078] [Table 2]

[0079] From Table 2, it can be seen that the manufacturing methods of the bales in Examples 1 to 15 include a washing step in which washing is performed with washing water containing an oxidizing agent, and the median area of ​​the waste paper is 20 cm 2 More than 150cm 2Because the amount of bacteria adhering to the waste paper contained in the bale is less than 100%, it has been confirmed that the number of bacteria adhering to the waste paper contained in the bale is reduced, the bale has excellent resistance to decay, and the bale also has excellent disintegration properties. On the other hand, in the manufacturing methods of the bales of Comparative Examples 1 and 2, Comparative Example 1 did not have a washing step, and Comparative Example 2 did not contain an oxidizing agent in the washing water, so the number of bacteria attached to the waste paper contained in the bales was high, and the rotting resistance was also poor. In addition, in the manufacturing method of the bale of Comparative Example 3, the median area of ​​the waste paper was 150 cm 2 In addition, in the manufacturing method of the bale of Comparative Example 4, the median area of ​​the waste paper was 20 cm 2 Because the temperature was less than 100°C, the number of bacteria attached to the waste paper contained in the bale was high, and the resistance to decay was also poor. Furthermore, the manufacturing methods of the bales in Comparative Examples 5 and 6 used acidic or alkaline washing water, but did not contain an oxidizing agent, resulting in a large number of bacteria adhering to the waste paper contained in the bales and poor decay resistance. [Industrial Applicability]

[0080] Because the bale manufacturing method of the present invention has the above-mentioned characteristics, the number of bacteria attached to the waste paper contained in the bale is reduced, the waste paper has excellent putrefaction resistance, and the waste paper contained in the bale also has excellent disintegration properties.

Claims

1. a washing step of washing waste paper having at least a resin layer and a paper base layer with washing water containing an oxidizing agent; and a molding step of compressing and molding the waste paper to obtain a bale. The basis weight of the waste paper is 100 g / m ２ That's all, The median area of ​​the waste paper is 20 cm ２ More than 150cm ２ Below is the How the veil is made.

2. 2. The method for producing a veil according to claim 1, wherein the oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, ozone, and sodium hypochlorite.

3. In the waste paper, 1 cm of waste paper after storing for 7 days ２ The number of bacteria adhering to the surface per 10 CFU / cm ２ The method for producing a bale according to claim 1 or 2, wherein the thickness is less than 1 / 2 mm.

4. The median density of the waste paper is 0.70 g / cm ３ The method for producing a bale according to claim 1 or 2, wherein the bale is made of a polyethylene terephthalate.

5. The method for manufacturing a bale according to claim 1 or 2, wherein the water absorbency of the waste paper is 25% or more and 85% or less.

6. The method for manufacturing a bale according to claim 1 or 2, wherein the content of the sizing agent in the paper base layer of the recycled paper is 0.2% by mass or more and 2.1% by mass or less.

7. The method for manufacturing a bale according to claim 1 or 2, wherein the waste paper further comprises a metal layer.

8. The molding pressure in the molding process is 500 kN / m ２ More than 2500kN / m ２ 3. The method for producing a bale according to claim 1 or 2, wherein:

9. Bale density is 0.3t / m ３ 1.0t / m or more ３ 3. The method for producing a bale according to claim 1 or 2, wherein:

10. The method for producing a bale according to claim 1 or 2, further comprising a crushing step of crushing the waste paper before the molding step.

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