Bale and method for manufacturing bale

Abstract

To provide a bale which is excellent in putrefaction resistance and is also excellent in disintegration properties of waste paper; and to provide a method for manufacturing the bale.SOLUTION: There is provided a bale comprising waste paper having at least a resin layer and a paper base material layer. In the bale, a basis weight of the waste paper is 100 g / m2 or more, and a median value of an area of the waste paper is 20 cm2 or more and 150 cm2 or less. There is also provided a method for manufacturing a bale, comprising a molding step of subjecting waste paper having at least a resin layer and a paper base material layer to compression molding to obtain the bale. In the method, a basis weight of the waste paper is 100 g / m2 or more, and a median value of an area of the waste paper is 20 cm2 or more and 150 cm2 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a bale and a method for making 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2010-521312 [Patent Document 2] International Publication No. 1998 / 33643 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 progress of decay caused by food residue and other contaminants remaining on the waste paper. Furthermore, depending on the state 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 bale that is excellent in rot resistance and in the disintegration properties of waste paper, and a method for producing said bale. [Means for solving the problem]

[0006] The present inventors have discovered that the above-mentioned problems can be solved by a bale made of waste paper having a basis weight equal to or greater than a specific value and a median area within a certain range. That is, the present invention relates to the following [1] to

[12] . [1] A bale made of recycled paper having at least a resin layer and a paper base layer, 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 Below is the veil [2] The bale according to [1], wherein the pH of the water after soaking the waste paper in water at a temperature of 23°C for 24 hours is 6.0 or higher. [3] The median density of the waste paper is 0.70 g / cm 3 The veil according to [1] or [2] above. [4] The bale according to any one of [1] to [3], wherein the water absorbency of the waste paper over 24 hours is 25% or more and 85% or less. [5] The bale according to any one of [1] to [4], 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. [6] Density is 0.3t / m 3 More than 1.0t / m 3 A veil according to any one of [1] to [5] below. [7] The bale according to any one of [1] to [6], wherein the waste paper further has a metal layer. [8] A method for manufacturing a bale by compressing and molding waste paper having at least a resin layer and a paper base layer, wherein 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 a method for manufacturing a veil. [9] Bale forming pressure: 500kN / m 2 More than 2500kN / m 2 [8] A method for producing a veil according to the following:

[10] The method for manufacturing a bale according to [8] or [9], further comprising a crushing step of crushing waste paper before the molding step.

[11] The method for producing a bale according to any one of [8] to

[10] , further comprising a washing step of washing the waste paper before the molding step.

[12] The method for manufacturing a bale according to

[11] , wherein the washing step is a step of washing the waste paper with neutral or alkaline washing water. [Effects of the Invention]

[0007] According to the present invention, a bale that is excellent in rot resistance and in waste paper disintegration properties, and a method for producing the bale are provided. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Veil] The bale of this embodiment is made of recycled paper having at least a resin layer and a paper base layer, and the basis weight of the recycled paper is 100 g / m 2 or more, and the median area of ​​the waste paper is 20 cm2 More than 150cm 2 The following is the result. The bale of this embodiment has excellent decay resistance and excellent repulping properties for waste paper. The reason for this is not clear, but 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 2 Such laminated paper is often used as food packaging. Therefore, when used as waste paper, food residue and other contaminants on the waste paper cause the paper to decay, resulting in the generation of a putrid odor, which may prevent the paper from being recycled. 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 the maceration property. In contrast, the bale of this embodiment has a median area of ​​waste paper forming the bale of 20 cm 2 Therefore, it is possible to form appropriate gaps between the waste paper in the bale, which is thought to be able to suppress the progression of waste paper decay. 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 recycled paper is 100 g / m2 in order to improve the disintegration property of the recycled paper. 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 20cm2 from the viewpoint of improving the decay resistance and disintegration of the waste paper. 2 More than 150cm 2less 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. 2 More than 120g / m 2 Less than 10 g / m, more preferably2 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 properties of waste paper, 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. 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 individual 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 recycled paper is preferably 80 g / m from the viewpoint of improving the disintegration property of the recycled paper. 2 More than 400g / m 2 or less, more preferably 100 g / m 2 More than 350g / m 2 More preferably, 120 g / m or less 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, 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 content of sizing agent in the paper base layer of waste paper is 0.2% by mass or more, the moisture remaining in the waste paper is reduced when the waste paper is washed before bale formation, etc., thereby improving decay resistance. Also, when the content of sizing agent in the paper base layer of waste paper is 2.1% by mass or less, sufficient water can easily penetrate into the waste paper during the maceration process when the bale is recycled, thereby improving the maceration properties of the waste paper. 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 agents and wet strength agents 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 improving decay resistance and improving the disintegration properties 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 viewpoint of improving decay resistance and disintegration properties of the waste paper. 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 viewpoint of improving decay resistance 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. If the thickness of the metal layer is 1 μm or more, the metal layer is prevented from becoming too fine during the pulverization process of the waste paper when the bale is recycled, making the pulverization process more efficient. Also, if the thickness of the metal layer is 50 μm or less, the penetration of moisture into the waste paper is less likely to be hindered, further improving the pulverization 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] In this embodiment, the pH of the water after immersing the waste paper in water at a temperature of 23°C for 24 hours is preferably 6.0 or higher, more preferably 7.0 or higher, even more preferably 8.0 or higher, and even more preferably 12.0 or higher. If the pH of the water after soaking the waste paper for 24 hours at 23°C is 6.0 or higher, the growth of bacteria that promote bale decay is inhibited, thereby further improving decay resistance. The pH of the water after immersing the waste paper in water at a temperature of 23°C for 24 hours is measured by the method described in the Examples.

[0030] 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 When the median density of the waste paper is within the above-mentioned upper limit range, sufficient water can easily penetrate into the waste paper during the pulping process when the waste paper is recycled, thereby improving the pulpability of the waste paper. The median density of waste paper can be adjusted by the press line pressure during dehydration when making the paper base layer from waste paper raw material.

[0031] 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 during the disintegration process when the bale is recycled, improving the disintegration properties of the wastepaper. Furthermore, when the 24-hour water absorbency of wastepaper is 85% or lower, the amount of water remaining in the wastepaper is reduced when the wastepaper is washed before bale formation, improving its decay resistance. 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.

[0032] 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

[0033] 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

[0034] 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, increasing the number of escape routes for moisture within the bale, further inhibiting the growth of bacteria that cause putrid odors and improving decay resistance.

[0035] In this embodiment, the bale may contain waste paper other than the above-mentioned waste paper, as long as the effects of the present invention are not impaired. Furthermore, in this embodiment, the bale may contain foreign matter other than the above-mentioned 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-mentioned 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.

[0036] (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.

[0037] [Bale manufacturing method] The method for producing a bale 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, 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. The manufacturing method of the bale of this embodiment is to make the median area of ​​the waste paper bales 20 cm 2 More than 150cm 2 By satisfying the above condition, the decay resistance of the bale and the disintegration property of the waste paper are improved.

[0038] The waste paper used in the method for manufacturing the bale of this embodiment is the same as the waste paper exemplified in the bale of this embodiment described above.

[0039] (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.

[0040] 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 / m2 or less, more preferably 1000 kN / m 2 More than 2000kN / m 2 The following is the result. When the bale forming pressure is within the above range, the density of the bale falls within the desired bale density range described above, which further improves the rotting resistance of the bale and the remacability of the waste paper.

[0041] (Crushing process) The bale manufacturing method of this embodiment preferably includes a crushing step of crushing the waste paper before bale formation. That is, the bale manufacturing method of this embodiment preferably includes a crushing step of crushing the waste paper before the bale forming step. The crushing step ensures that the waste paper to be subjected to the forming step is of an appropriate size, which makes the disintegration process more efficient and improves the disintegration properties of the waste paper when the bale is recycled, for example. As the crusher used in the crushing step, it is preferable to use a single-shaft crusher, a double-shaft crusher, etc., depending on the size of the waste paper after crushing. Furthermore, when the crushing step is carried out and the washing step described below is carried out at the same time, it is preferable to use a crushing and washing machine, etc.

[0042] In the shredding step, the number of hooks of the shredding machine is preferably 2 or more and 10 or less, more preferably 4 or more and 8 or less, from the viewpoint of keeping the median area of ​​the waste paper within a desired range.

[0043] (Cleaning process) The bale manufacturing method of this embodiment preferably includes a washing step of washing the waste paper before bale formation. That is, the bale manufacturing method of this embodiment preferably includes a washing step of washing the waste paper before the forming step. Furthermore, if the bale manufacturing method of this embodiment includes a crushing step before the washing step, the washing step is preferably a step of washing the waste paper after the crushing step.

[0044] Furthermore, in the washing step, the washing water used to wash the waste paper is preferably neutral or alkaline washing water, and more preferably alkaline washing water. That is, in the bale washing method of this embodiment, the washing step is preferably a step of washing the waste paper with neutral or alkaline washing water, and more preferably a step of washing the waste paper with alkaline washing water. In this specification, "neutral" refers to a pH range of greater than 6.5 and less than 7.5, and "alkaline" refers to a pH range of 7.5 or higher. If the washing water is neutral or alkaline, proteins and other substances that serve as a nutrient source for bacteria that promote rotting of the bale can be removed from the waste paper, further improving the rotting resistance of the bale.

[0045] Furthermore, in the washing step, the pH of the washing water is preferably greater than 6.5 and less than 14.0, more preferably between 7.0 and 12.0, even more preferably between 7.5 and 11.0, still more preferably between 8.0 and 10.5, and even more preferably between 8.5 and 10.0, from the viewpoint of improving the spoilage resistance of the bale.

[0046] In the washing step, the washing water is preferably water or an aqueous sodium hydroxide solution, more preferably an aqueous sodium hydroxide solution, from the viewpoint of improving the decay resistance of the bale. When the washing water is an aqueous sodium hydroxide solution, the concentration of sodium hydroxide in the washing water 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 1% by mass, even more preferably 0.0003% by mass (3 ppm by mass) to 0.01% by mass (100 ppm by mass), and still more preferably 0.0004% by mass (4 ppm by mass) to 0.001% by mass (10 ppm by mass), from the viewpoint of improving the rotting resistance of the bale and the maintainability of the equipment.

[0047] The washing step may be carried out before the crushing step, after the crushing step and before the molding step, or simultaneously with the crushing step. 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 the washing step simultaneously, and it is more preferable to carry out the crushing step and the 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. [Example]

[0048] 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.

[0049] [Bale manufacturing] Example 1 (recycled paper) The waste paper used was aseptic packaging paper collected after using the paper of Composition 1 in Table 1 as a beverage carton. The contents of the paper used as a beverage carton included milk, soy milk, and fruit juice. 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 crushing and washing machine (A-tech Corporation, paper container recycling machine PPRS), crushed with blades having six hooks, and washed with washing water (sodium hydroxide aqueous solution, concentration: 5 ppm by mass, pH: 9.0, fresh water consumption rate: 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.

[0050] <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:

[0051] 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:

[0052] 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 an aqueous sodium hydroxide solution (concentration: 5% by mass, pH: 14.0).

[0053] <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 water (without the addition of sodium hydroxide, pH: 7.0).

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] Example 12 The bale forming pressure during the bale forming process was set to 1400 kN / m 2 A veil was obtained in the same manner as in Example 1, except that:

[0061] 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:

[0062] 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.

[0063] 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.

[0064] <Comparative Example 1> 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:

[0065] <Comparative Example 2> 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:

[0066] Table 1 shows the composition of the waste paper used in the examples and comparative examples.

[0067] [Table 1]

[0068] [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.

[0069] <pH of water after soaking waste paper in water at 23°C for 24 hours> Waste paper randomly sampled from the bales of the Examples and Comparative Examples was dried to perfection, and then ion-exchanged water adjusted to 23°C was added to the waste paper so that the mass was 100 times the mass of the waste paper after drying, and the waste paper was immersed in water for 24 hours. The pH of the water after immersing the waste paper was then measured using a pH meter (F-12, manufactured by Horiba, Ltd.), and this was taken as the pH of the water after immersing the waste paper at a water temperature of 23°C for 24 hours.

[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] <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 three 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.

[0075] <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%

[0076] Table 2 shows the measurement and evaluation results for the examples and comparative examples.

[0077] [Table 2]

[0078] From Table 2, the median area of ​​the waste paper in the bales of Examples 1 to 15 is 20 cm 2 More than 150cm 2It was confirmed that the composition has excellent decay resistance and excellent reclaimed paper disintegration properties. On the other hand, the bale of Comparative Example 1 had a median waste paper area of ​​150 cm 2 The bale of Comparative Example 2 had a median waste paper area of ​​20 cm 2 As a result, the decay resistance was poor. [Industrial Applicability]

[0079] The bale of the present invention has the above-mentioned characteristics, and therefore has excellent decay resistance and excellent repulping properties for waste paper.

Claims

1. A bale made of recycled paper having at least a resin layer and a paper base layer, 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 veil.

2. 2. The bale according to claim 1, wherein the pH of the water after the waste paper is soaked in water at a temperature of 23°C for 24 hours is 6.0 or higher.

3. The median density of the waste paper is 0.70 g / cm ３ The veil according to claim 1 or 2.

4. 3. The bale according to claim 1, wherein the water absorbency of the waste paper over 24 hours is 25% or more and 85% or less.

5. The bale according to claim 1 or 2, wherein the content of 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.

6. Density is 0.3t / m ３ 1.0t / m or more ３ 3. The veil according to claim 1 or 2, wherein:

7. 3. The bale of claim 1 or 2, wherein the waste paper further comprises a metal layer.

8. The method 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, 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 The following is a method for manufacturing a veil.

9. Bale forming pressure: 500 kN / m ２ More than 2500kN / m ２ 9. The method for producing a bale according to claim 8, wherein:

10. The method for producing a bale according to claim 8 or 9, further comprising a crushing step of crushing the waste paper before the molding step.

11. The method for producing a bale according to claim 8 or 9, further comprising a washing step of washing the waste paper prior to the molding step.

12. The method for producing a bale according to claim 11, wherein the washing step is a step of washing the waste paper with neutral or alkaline washing water.

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