How the veil is made

Abstract

To provide a method for producing a bale which has excellent shape retention for the formed bale and also has excellent disintegration properties for waste paper pieces contained in the bale. The method includes a molding step of compressing and molding waste paper pieces having at least a resin layer and a paper base layer to obtain a bale, and the waste paper pieces have a basis weight of 100 g / m 2 The method for producing a bale is as described above, wherein the water absorbency of the waste paper pieces over 24 hours is 15% or more and 85% or less.

Description

[Technical field]

[0001] The present invention relates to a method for producing a veil. [Background technology]

[0002] In recent years, efforts to eliminate plastic have been accelerating worldwide due to growing interest in reducing waste and environmental issues. As a result, in order to reduce the amount of plastic used in various products, efforts are being made to change from plastic-only raw materials to paper raw materials that combine paper and plastic. Conventionally, waste paper laminated with a resin layer was considered taboo and was not reused, but due to the growing interest in reducing waste and environmental issues, there is now a demand for the use of laminated waste paper. Generally, waste paper is temporarily stored in bales for recycling.

[0003] Patent Document 1 discloses an apparatus for forming a bale from compressible waste materials such as waste paper and discarded cartons, the apparatus comprising a press housing having a substantially rectangular parallelepiped shape and including at least one compression chamber and a press plate that can be reciprocated in the press 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 a bale by a bale forming device as disclosed in Patent Documents 1 and 2, and then it is recycled. However, waste paper having a resin layer in addition to a paper base layer may not be able to maintain the bale shape and may collapse. Also, depending on the state of the formed bale, the defibration property may be insufficient, and the recyclability may be reduced. An object of the present invention is to provide a method for producing a bale which provides excellent shape retention for the formed bale and also provides excellent disintegration properties for the waste paper contained in the bale. [Means for solving the problem]

[0006] The inventors have discovered that in a bale manufacturing method that includes a molding step in which waste paper pieces having at least a resin layer and a paper base layer are compressed and molded to obtain a bale, the above-mentioned problem can be solved by providing the waste paper pieces with a basis weight of a specific value or more and a water absorbency within a certain range. The present invention relates to the following [1] to [9]. [1] A method for producing a bale by compressing and molding waste paper pieces having at least a resin layer and a paper base layer, the waste paper pieces having a basis weight of 100 g / m 2 The above-mentioned method for producing a bale, wherein the water absorbency of the waste paper pieces for 24 hours is 15% or more and 85% or less. [2] The method for manufacturing a bale described in [1], wherein the folding strength of the waste paper pieces is 20 gf or more and 350 gf or less. [3] The median area of ​​the waste paper pieces is 20 cm 2 More than 200cm 2 A method for producing a veil according to [1] or [2], which is as follows: [4] The density of the bale is 0.3 t / m 3 More than 1.0t / m 3The method for producing a veil according to any one of [1] to [3] below. [5] The method for manufacturing a bale according to any one of [1] to [4], wherein the content of the sizing agent in the paper base layer of the waste paper pieces is from 0.2% by mass to 2.1% by mass. [6] The method for manufacturing a bale according to any one of [1] to [5], wherein the waste paper pieces further have a metal layer. [7] Bale forming pressure: 500 kN / m 2 More than 2500kN / m 2 The method for producing a veil according to any one of [1] to [6] below. [8] The method for producing a bale according to any one of [1] to [7], further comprising a crushing step of crushing waste paper before forming the bale. [9] A method for producing a bale according to any one of [1] to [8], comprising a washing step of washing the waste paper or waste paper pieces before forming the bale. Effect of the Invention

[0007] According to the present invention, there is provided a method for producing a bale which provides excellent shape retention for the formed bale and excellent disintegration properties for the waste paper pieces contained in the bale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [How the veil is manufactured] The method for producing a bale according to the present embodiment includes a molding step of compressing and molding waste paper pieces having at least a resin layer and a paper base layer (hereinafter, also simply referred to as "waste paper pieces") to obtain a bale, and the basis weight of the waste paper pieces is 100 g / m 2 The water absorbency of the waste paper pieces for 24 hours is 15% or more and 85% or less. According to the bale manufacturing method of this embodiment, the formed bale has excellent shape retention, and further, the waste paper pieces contained in the bale have excellent disintegration properties. Although the reason for this is not clear, it is thought to be as follows. Generally, waste paper pieces containing a resin layer tend to have poor defibration properties when they are subjected to a defibration process because the resin layer prevents water from penetrating. 2 Since waste paper pieces having the above structure have a large force that causes them to return to their original expanded state even when compressed, bales containing such waste paper pieces tend to have difficulty in maintaining their shape. In contrast, in the bale manufacturing method of this embodiment, since the 24-hour water absorbency of the waste paper pieces is 15% or more, when the resulting bale is recycled, water will sufficiently penetrate into the waste paper pieces, which is believed to improve disaggregation. Also, since the 24-hour water absorbency of the waste paper pieces is 85% or less, when the waste paper pieces are washed or the resulting bale is exposed to rain during storage, etc., and the bale becomes moist, the shape of the bale is prevented from collapsing due to the influence of the moisture, and the shape retention of the resulting bale is believed to be improved.

[0009] The basis weight of the waste paper pieces is set to 100 g / m from the viewpoint of improving the shape retention and disintegration properties of the resulting bale. 2 or more, preferably 120 g / m 2 More than 600g / m 2 Less than 140g / m 2 More than 500g / m 2 More preferably, 160 g / m 2 More than 400g / m 2 More preferably, 180 g / m 2 More than 300g / m 2 The following is the result. The basis weight of the waste paper pieces is measured by the method described in the Examples.

[0010] The 24-hour water absorbency of the waste paper pieces is from 15% to 85%, preferably from 30% to 75%, and more preferably from 45% to 65%, from the viewpoint of improving the shape retention and disintegration properties of the resulting bale. The water absorbency of the waste paper pieces is adjusted, for example, by the content of the sizing agent in the paper base layer of the waste paper pieces. The 24-hour water absorbency of the waste paper pieces is determined from the rate of increase in the mass of the waste paper pieces when the waste paper pieces are immersed in water for 24 hours, and is specifically determined by the method described in the examples.

[0011] (piece of old paper) In this embodiment, the waste paper pieces that are the raw material for the bale have at least a resin layer and a paper base layer. [Resin Layer] The resin constituting the resin layer in the waste paper pieces is not particularly limited, but examples thereof include polyolefins such as high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), 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, ethylene-α-olefin copolymer, etc. In addition, when the waste paper pieces have 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] From the viewpoint of improving the shape retention and disintegration properties of the resulting bale, the thickness of the resin layer in the waste paper pieces 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 pieces have multiple resin layers, the thickness of the resin layer in the waste paper pieces refers to the total thickness of the respective resin layers.

[0013] The basis weight of the resin layer in the waste paper pieces is preferably 5 g / m from the viewpoint of improving the shape retention and disintegration properties of the resulting bale. 2 More than 120g / m 2 Less than 10 g / m 2 More than 100g / m 2 More preferably, 15 g / m or less 2 More than 80g / m 2 More preferably, 20 g / m or less 2 More than 60g / m 2 In addition, when a piece of waste paper has a plurality of resin layers, the basis weight of the resin layers in the piece of waste paper indicates the total basis weight of the respective resin layers.

[0014] [Paper base layer] The paper base layer is not particularly limited as long as it is a paper that is generally used with plant-derived wood pulp as the main component. The wood pulp is not particularly limited, but examples thereof include 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 base 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 the pigment include, but are not limited to, heavy calcium carbonate, kaolin, plastic pigment, etc. Examples of the binder include, but are not limited to, starch, styrene-acrylic copolymer latex, styrene-butadiene copolymer latex, olefin-carboxylic acid emulsion copolymer latex, etc.

[0016] From the viewpoint of improving the shape retention and disintegration properties of the resulting bale, the thickness of the paper base layer in the waste paper pieces 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. In addition, when a waste paper piece has a plurality of paper base layers, the thickness of the paper base layer in the waste paper piece indicates the total thickness of each of the paper base layers.

[0017] The basis weight of the paper base layer in the waste paper pieces is preferably 80 g / m from the viewpoint of improving the shape retention and disintegration properties of the resulting bale. 2 More than 400g / m 2 Less than 100 g / m 2 More than 350g / m 2 More preferably, 120 g / m 2 More than 300g / m 2 or less, even more preferably 150 g / m 2More than 250g / m 2 The following is the result. In addition, when a waste paper piece has a plurality of paper base layers, the basis weight of the paper base layers in the waste paper piece indicates the total basis weight of the respective paper base layers.

[0018] In this embodiment, the waste paper pieces may have other layers in addition to the resin layer and the paper base layer, such as a metal layer, a printed layer, and an adhesive layer.

[0019] [Metal layer] In this embodiment, the waste paper piece may further have a metal layer. In this embodiment, the metal layer of the waste paper piece preferably contains aluminum. In addition, in this embodiment, the metal layer of the waste paper piece is more preferably aluminum foil. When the waste paper pieces contain a metal layer, the thickness of the metal layer in the waste paper pieces 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 a piece of waste paper has multiple metal layers, the thickness of the metal layers in the piece of waste paper refers to the total thickness of each metal layer. By making the thickness of the metal layer 1 μm or more, the metal layer is prevented from becoming fine when the resulting bale is disintegrated, making the disintegration process more efficient. Also, by making the thickness of the metal layer 50 μm or less, the penetration of moisture into the waste paper pieces is less likely to be hindered, making the disintegration process more efficient.

[0020] When the waste paper pieces contain a metal layer, the basis weight of the metal layer in the waste paper pieces is preferably 8 g / m from the viewpoint of improving the shape retention and disintegration properties of the resulting bale. 2 More than 30g / m 2 Less than 10 g / m 2 More than 27g / m 2 More preferably, 12 g / m or less 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. In addition, when a piece of waste paper has a plurality of metal layers, the basis weight of the metal layers in the piece of waste paper indicates the total basis weight of the respective metal layers.

[0021] [Printing layer] In this embodiment, the waste paper pieces may 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 one surface or on a part of the layer on which the printed layer is applied.

[0022] In this embodiment, the folding strength of the waste paper pieces is preferably 20 gf or more and 350 gf or less, more preferably 25 gf or more and 300 gf or less, even more preferably 30 gf or more and 200 gf or less, still more preferably 35 gf or more and 100 gf or less, and even more preferably 40 gf or more and 70 gf or less. Although there is no particular lower limit to the bending strength, from the viewpoint of manufacturing, the lower limit is preferably 20 gf or more. Furthermore, by setting the bending strength to 350 gf or less, the force that causes the waste paper pieces to return to their original shape is suppressed, and the shape retention of the bale is further improved. In this embodiment, the folding strength of the waste paper pieces can be adjusted to a desired range by adjusting the amount of paper strength agent added to the paper base layer of the waste paper pieces, the basis weight of the waste paper pieces, and the thickness of the waste paper pieces. The folding strength of the waste paper pieces is measured by the method described in the Examples.

[0023] [Adhesive layer] In this embodiment, the waste paper pieces may further have an adhesive layer, which is formed mainly for adhering the metal layer to the paper base layer and / or the metal layer to the resin layer when the waste paper has a metal layer. Examples of resins constituting the adhesive layer include ethylene-methacrylic acid copolymer resin (EMAA), ethylene-acrylic acid copolymer resin (EAA), ethylene-vinyl acetate copolymer resin (EVA), ionomer resin (IO), ethylene-methyl acrylate copolymer resin (EMA), ethylene-ethyl acrylate copolymer resin (EEA), ethylene-butyl acrylate copolymer resin (EBA), and the like.

[0024] In this embodiment, the median area of ​​the waste paper pieces is preferably 20 cm 2 More than 200cm 2 Less than or equal to 30cm, preferably 2 over 180cm 2 Less than 40cm, more preferably 2 More than 150cm 2 Less than 50cm, more preferably 50cm 2 More than 120cm 2 Less than 60cm, more preferably 2 More than 90cm 2 The following is the result. The median area of ​​the waste paper pieces is 20 cm 2 By setting the size of the waste paper pieces at 200 cm or more, the shape retention of the resulting bale is improved. 2 When the content is equal to or less than this, the disintegration property is further improved. The median area of ​​the waste paper pieces is measured by the method described in the Examples.

[0025] In this embodiment, the content of sizing agent in the paper base layer in the waste paper pieces 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, and even more preferably 0.6% by mass or more and 1.6% by mass or less, from the viewpoint of improving the shape retention and disintegration properties of the resulting bale. The content of sizing agent in the paper base layer of the waste paper pieces does not change before and after the bale is formed. That is, the content of sizing agent in the paper base layer of the waste paper pieces is the same as the content of sizing agent in the paper base layer of the waste paper pieces contained in the resulting bale. The content of sizing agent in the paper base layer of the waste paper pieces is measured by the method described in the Examples.

[0026] In this embodiment, examples of the sizing agent in the paper base layer of the waste paper pieces include rosin sizing agents, synthetic sizing agents, and petroleum resin-based sizing agents.

[0027] In this embodiment, the amount of paper strength enhancer added to the waste paper pieces relative to 100 parts by mass of raw pulp in the pulp slurry when preparing the paper base layer is preferably 0.5 to 1.5 parts by mass, more preferably 0.7 to 1.3 parts by mass, and even more preferably 0.9 to 1.1 parts by mass, from the viewpoint of improving the shape retention and disintegration properties of the resulting bale. The content of the paper strength enhancer in the paper base layer is preferably 0.5 to 1.5% by mass, more preferably 0.7 to 1.3% by mass, and even more preferably 0.9 to 1.1% by mass. The content of the strength agent in the paper base layer of the waste paper pieces does not change before and after the bale is formed. That is, the content of the strength agent in the paper base layer of the waste paper pieces is the same as the content of the strength agent in the paper base layer of the waste paper pieces contained in the resulting bale.

[0028] In this embodiment, the paper strength enhancer in the paper base layer of the waste paper pieces includes a dry strength enhancer and a wet strength enhancer. Examples of the dry strength enhancer include polyacrylamide, cationic starch, carboxymethyl cellulose, etc. Examples of the wet strength enhancer include polyamide polyamine epichlorohydrin, urea formaldehyde resin, melamine formaldehyde resin, etc.

[0029] Examples of the waste paper pieces include waste paper pieces derived from food and beverage containers, paper bags, and paper cutlery. Examples of food and beverage containers include liquid containers and food containers, and more specifically, paper trays, aseptic containers, paper cups, milk cartons, etc. Among these, the waste paper pieces are preferably at least one type selected from waste paper pieces from aseptic containers and waste paper pieces from paper cups. The waste paper pieces for aseptic containers have, for example, the following configurations (a1) to (a2). In the following configurations, the layer on the right side indicates the layer that was in contact with the contents when used as an aseptic container. In the following configurations, the "(printed layer)" and "(adhesive layer)" are optional layers, and may or may not be present as necessary. In the following configurations, 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 following configurations, 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

[0030] The waste paper pieces for paper cups preferably have the following configurations (b1) to (b4), for example. In the following configurations, the layer on the right side indicates the layer that was in contact with the contents when used as a paper cup. In the following configurations, the "(printed layer)" and "(adhesive layer)" are optional layers, and may or may not be present as necessary. In the following configurations, 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 following configurations, 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

[0031] (molding process) This embodiment includes a molding step of compressing and molding waste paper pieces having at least a resin layer and a paper base layer to obtain a bale. As a bale forming device in the molding step, a known bale forming device may be appropriately used.

[0032] In the forming step, the bale forming pressure is preferably 500 kN / m 2 More than 2500N / m 2 Less than or equal to 1000 kN / m 2 More than 2300N / m 2 or less, more preferably 1200 kN / m 2 More than 2000N / m 2 The following is the result. By keeping the bale molding pressure within the above range, the density of the resulting bale falls within the desired bale density range described below, and the shape retention and disintegration properties of the resulting bale are improved.

[0033] (Crushing process) In this embodiment, it is preferable to have a crushing step of crushing the waste paper before bale formation. That is, the bale manufacturing method of this embodiment preferably has a crushing step of crushing the waste paper before the above-mentioned forming step. By having the crushing step, the waste paper pieces to be subjected to the forming step are made uniform in size to an appropriate level, so that when the resulting bale is subjected to recycling, for example, by recovering pulp fibers from the bale, the defibration process becomes more efficient and the defibration property is improved. In addition, the shape retention of the resulting bale is improved. 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 pieces after crushing. In addition, when the crushing step is performed, if a washing step described below is performed at the same time, it is preferable to use a crushing and washing machine, etc. In this embodiment, if the shredding process is not performed, unshredded waste paper may be used as waste paper pieces as is.

[0034] In the crushing step, the number of hooks of the crusher 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 pieces within a desired range.

[0035] (Cleaning process) In this embodiment, it is preferable to have a washing step of washing the waste paper or waste paper pieces before the bale forming process. That is, it is preferable that the bale manufacturing method of this embodiment has a washing step of washing the waste paper or waste paper pieces before the above-mentioned forming process. Also, when the bale manufacturing method of this embodiment has a crushing process before the washing process, it is preferable that the washing process is a process of washing the waste paper pieces after the crushing process. In the washing step, water is usually used as the washing water for washing the waste paper pieces. The washing step may be carried out before the crushing step, after the crushing step and before the shaping step, or the crushing step and the 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 shaping 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. As the apparatus used in the washing step, a known apparatus can be appropriately used. When the crushing step and the washing step are carried out simultaneously, it is preferable to appropriately use a crushing / washing machine or the like.

[0036] [Veil] In this embodiment, the bale can be obtained by the above-mentioned bale manufacturing method. Therefore, the bale in this embodiment has excellent shape retention and excellent disintegration properties of the waste paper pieces contained in the bale.

[0037] In this embodiment, the density of the bale is preferably 0.3 t / m 3 More than 1.0t / m 3 Less than or equal to 0.4t / m 3 More than 0.8t / m 3 Less than 0.5t / m, more preferably 0.5t / m 3 More than 0.7t / m 3 The following is the result. Bale density is 0.3t / m 3 By setting the density of the bale at 1.0t / m or more, the waste paper pieces are sufficiently in close contact with each other inside the bale, so that the shape retention is improved. 3By keeping the thickness below 100 mm, it is possible to prevent the waste paper pieces from being unnecessarily compacted inside the bale, which makes it easier to loosen the bale when it is recycled, improving the disintegration properties.

[0038] In this embodiment, the bale obtained is made from the waste paper pieces described above. The waste paper pieces do not change in composition or other physical properties before and after bale formation. In other words, in this embodiment, the form of the waste paper pieces contained in the bale is the same as that of the waste paper pieces exemplified in the bale manufacturing method described above. In this embodiment, the obtained bale may contain waste paper other than the above waste paper pieces, as long as the effects of the present invention are not impaired. In addition, in this embodiment, the obtained bale may contain foreign matter other than the above waste paper pieces, 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 pieces in the obtained bale is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass. EXAMPLES

[0039] The features of the present invention will be described in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing 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 interpreted 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. In addition, the operations of the examples and comparative examples were carried out under conditions of 23±1°C and 50±2% RH, unless otherwise specified.

[0040] [How the veil is manufactured] <Example 1> (piece of old paper) The waste paper pieces used were those of composition 1 in Table 1. The paper base layer of the waste paper pieces in Example 1 was made from a paper stock (pulp slurry) to which 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) was added, 1.0 part by mass of a rosin sizing agent (Sizepine N-881, manufactured by Arakawa Chemical Industries, Ltd.) as a sizing agent, 1.0 part by mass of a polyacrylamide-based paper strength agent (PS117, manufactured by Arakawa Chemical Industries, Ltd.) as a paper strength agent, and 1.0 part by mass of aluminum sulfate were added. (Crushing process / Washing process) The waste paper pieces were placed in a crushing and washing machine (Paper container recycling machine PPRS, manufactured by A-tech Corporation), crushed using a blade with six hooks, and washed with water. (Bale forming process) Approximately 60 kg of waste paper pieces were fed into a bale compressor (Yuken Kogyo Co., Ltd., YB-32M-PA-10, 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 1000g to obtain a bale.

[0041] <Example 2> The waste paper pieces used were those of composition 2 in Table 1, and the bale forming pressure in the bale forming process was 1700 kN / m 2 A veil was obtained in the same manner as in Example 1, except that the above-mentioned was used. The paper base layer of the waste paper pieces in Example 2 was made from a paper stock (pulp slurry) to which 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) was added, 1.5 parts by mass of a rosin sizing agent (Sizepine N-881, manufactured by Arakawa Chemical Industries, Ltd.) as a sizing agent, 1.0 part by mass of a polyacrylamide-based paper strength agent (PS117, manufactured by Arakawa Chemical Industries, Ltd.) as a paper strength agent, and 1.0 part by mass of aluminum sulfate were added.

[0042] <Example 3> A bale was obtained in the same manner as in Example 1, except that the waste paper pieces used were those of Configuration 1, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 0.5 parts by mass per 100 parts by mass of raw pulp.

[0043] <Example 4> A bale was obtained in the same manner as in Example 1, except that the waste paper pieces used were those of Configuration 1, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 0.8 parts by mass per 100 parts by mass of raw pulp.

[0044] <Example 5> A bale was obtained in the same manner as in Example 1, except that the waste paper pieces used were those of Configuration 1, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 1.2 parts by mass per 100 parts by mass of raw pulp.

[0045] <Example 6> A bale was obtained in the same manner as in Example 1, except that the waste paper pieces used were those of Configuration 1, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 1.5 parts by mass per 100 parts by mass of raw pulp.

[0046] <Example 7> The waste paper pieces used were those of configuration 1, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 1.1 parts by mass per 100 parts by mass of raw pulp, and the bale forming pressure in the bale forming process was 1850 kN / m 2 A veil was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0047] <Example 8> The waste paper pieces used were those of configuration 1, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 1.2 parts by mass per 100 parts by mass of raw pulp, 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 the above-mentioned was used.

[0048] <Example 9> The waste paper pieces used were those of configuration 1, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 0.9 parts by mass per 100 parts by mass of raw pulp, and the bale forming pressure in the bale forming process was 1700 kN / m 2 A veil was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0049] <Example 10> The waste paper pieces used were those of configuration 1, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 0.8 parts by mass per 100 parts by mass of raw pulp, and the bale forming pressure in the bale forming process was 1650 kN / m 2 A veil was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0050] <Example 11> A bale was obtained in the same manner as in Example 2, except that the waste paper pieces used were those of configuration 2, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 1.2 parts by mass per 100 parts by mass of raw pulp.

[0051] <Example 12> A bale was obtained in the same manner as in Example 2, except that the waste paper pieces used were those of configuration 2, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 1.4 parts by mass per 100 parts by mass of raw pulp.

[0052] <Example 13> A bale was obtained in the same manner as in Example 2, except that the waste paper pieces used were those of configuration 2, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 1.8 parts by mass per 100 parts by mass of raw pulp.

[0053] <Example 14> A bale was obtained in the same manner as in Example 2, except that the waste paper pieces used were those of configuration 2, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 2.0 parts by mass per 100 parts by mass of raw pulp.

[0054] <Example 15> The waste paper pieces used were those of configuration 2, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 1.1 parts by mass per 100 parts by mass of raw pulp, and the bale forming pressure in the bale forming process was 1800 kN / m 2 A veil was obtained in the same manner as in Example 2, except that the above-mentioned was used.

[0055] <Example 16> The waste paper pieces used were those of configuration 2, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 1.2 parts by mass per 100 parts by mass of raw pulp, and the bale forming pressure in the bale forming process was 1850 kN / m 2 A veil was obtained in the same manner as in Example 2, except that the above-mentioned was used.

[0056] <Example 17> The waste paper pieces used were those of configuration 2, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 0.9 parts by mass per 100 parts by mass of raw pulp, and the bale forming pressure in the bale forming process was 1650 kN / m 2 A veil was obtained in the same manner as in Example 2, except that the above-mentioned was used.

[0057] <Example 18> The waste paper pieces used were those of configuration 2, in which the amount of paper strength agent added to the paper material (pulp slurry) when manufacturing the paper base layer was 0.8 parts by mass per 100 parts by mass of raw pulp, and the bale forming pressure in the bale forming process was 1600 kN / m 2 A veil was obtained in the same manner as in Example 2, except that the above-mentioned was used.

[0058] <Example 19> 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 the above-mentioned was used.

[0059] <Example 20> 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 the above-mentioned was used.

[0060] <Example 21> The bale forming pressure during the bale forming process is 1400 kN / m 2 A veil was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0061] <Example 22> The bale forming pressure during the bale forming process is 2200 kN / m 2 A veil was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0062] <Example 23> The crushing and washing processes were not carried out, and the bale forming pressure in the bale forming process was set at 2200 kN / m 2 A veil was obtained in the same manner as in Example 1, except that the above-mentioned was used.

[0063] <Example 24> The crushing and washing processes were not carried out, and the bale forming pressure in the bale forming process was set at 2000 kN / m 2 A veil was obtained in the same manner as in Example 2, except that the above-mentioned was used.

[0064] <Comparative Example 1> A bale was obtained in the same manner as in Example 1, except that the waste paper pieces used were those of Configuration 1, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 0.1 parts by mass per 100 parts by mass of raw pulp.

[0065] <Comparative Example 2> A bale was obtained in the same manner as in Example 2, except that the waste paper pieces used were those of configuration 2, in which the amount of sizing agent added to the paper material (pulp slurry) when producing the paper base layer was 2.2 parts by mass per 100 parts by mass of raw pulp.

[0066] The composition of the waste paper pieces used in the examples and comparative examples is shown in Table 1.

[0067] [Table 1]

[0068] [Evaluation and measurement methods] <Water absorption over 24 hours> The waste paper pieces used in the examples and comparative examples were completely dried, and then conditioned for 96 hours in a humidity-conditioned environment specified in JIS P 8111:1998. Approximately 10 g of the conditioned waste paper pieces were immersed in 1 L of water (water temperature: 23±1°C) for 24 hours, and the waste paper pieces were collected. The collected waste paper pieces were sandwiched between absorbent paper (manufactured by ADVANTEC, No. 26, 190 mm x 190 mm), and then rolled back and forth once with a metal roller (10 kg) without applying pressure to remove excess moisture, and this was used as the waste paper piece after immersion in water. The mass of the waste paper piece before and after immersion in water was measured (measured to the nearest 1 mg), and the water absorbency was calculated using the following calculation formula, which was used as the water absorbency of the waste paper piece for 24 hours. [Water absorption rate (%)] = ([Mass of wastepaper piece after immersion in water (g)] - [Mass of wastepaper piece before immersion in water (g)]) / [Mass of wastepaper piece before immersion in water (g)] × 100

[0069] <Bending strength> The waste paper pieces used in the examples and comparative examples were completely dried, and then conditioned for 96 hours in a humidity-controlled environment as specified in JIS P 8111: 1998. Waste paper samples (width 38 mm x length 70 mm) were prepared from the conditioned waste paper pieces, and the bending strength of the waste paper samples was measured using a bending stiffness tester (BST-150M, manufactured by Asahi Research Institute).

[0070] <Median area of ​​waste paper> Approximately 100 g of the waste paper pieces used in the examples and comparative examples were sieved (φ: 20 mm) to remove small waste paper pieces, and the remaining waste paper pieces were scanned using EPSON Scan to obtain images. The scanned images were analyzed using ImageJ, and the area of ​​each waste paper piece was obtained to calculate the median area.

[0071] <Sizing agent content> From the bales obtained in the Examples and Comparative Examples, waste paper pieces were randomly taken and dried. After drying, layers other than the paper base layer, such as the resin layer, were removed by grinding using a grinding device (manufactured by Sagawa Seisakusho Co., Ltd., grinding wheel dimensions φ50.8×12.7 mm) while checking the layer boundaries under a microscope, and the paper base layer was recovered. The additives in the paper base layer were quantified using pyrolysis gas chromatography (GCMS) under the following measurement conditions: Quantification was performed based on a calibration curve prepared using a rosin sizing agent (Sizepine N-881, manufactured by Arakawa Chemical Industries, Ltd.) of known concentration as a standard. (Measurement conditions) ·Pyrolysis furnace temperature: 450℃ Temperature conditions during measurement: 100 to 325°C, heated at 15°C / min. Column used: HP-5MS (Agilent Technologies)

[0072] <Bale density> The bale density was calculated from the weight of the waste paper pieces added during the bale forming process and the volume of the resulting bale.

[0073] <Shape retention> For the bales obtained in the examples and comparative examples, five PP bands (manufactured by Moriya Sangyo Co., Ltd., model number: 12 J-S1) were wrapped at equal intervals around the sides only using a cordless handheld packaging machine (manufactured by Strapack Co., Ltd., STB73, tightening strength 900N), and then stretch film (manufactured by Trusco Nakayama Co., Ltd., SF18-500) was wrapped around them so that the entire side of the bale was covered all the way around. The forklift tines were inserted directly between the bale and the ground, lifted vertically 1m, and then lowered to the ground. When the forklift tines were then pulled out from between the bale and the ground, the state of the bale falling out was checked and evaluated according to the following criteria. (Evaluation Criteria) A: Pieces of waste paper had fallen off the bale to a distance of less than 15cm. B: Pieces of waste paper had fallen off from the bale, extending over a distance of 15 cm to less than 30 cm. C: Pieces of waste paper had fallen off from the bale, extending over a distance of 30 cm to less than 45 cm. D: Pieces of waste paper had fallen off from the bale to a distance of more than 45 cm.

[0074] <Disintegrability> From the bales obtained in the Examples and Comparative Examples, 60 g of waste paper pieces were collected in an absolute dry weight 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 weight. The obtained pulp slurry was then fed into a flat screen (Kumagaya Riki Kogyo Co., Ltd., No. 230703, slit 6 cut) at a flow rate of 10 L / min for 15 minutes. The residue rate was calculated from the absolute dry weight 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 property. Fiber recovery rate (%) = {1-([residue rate (%)] / 100)} / proportion of the basis weight of the paper base layer in the basis weight of the waste paper piece × 100 Residue rate (%) = [Bone dry mass (g) of residue that did not pass through the flat screen] / [Solid mass (g) of pulp slurry fed 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%

[0075] Table 2 shows the measurement and evaluation results for the examples and comparative examples.

[0076] [Table 2]

[0077] From Table 2, it was confirmed that the bales obtained in Examples 1 to 24 had excellent shape retention and also excellent disintegration properties because the 24-hour water absorbency of the waste paper pieces was 15% or more and 85% or less. On the other hand, the bale obtained in Comparative Example 1 had poor shape retention because the 24-hour water absorbency of the waste paper pieces was greater than 85%, and the bale obtained in Comparative Example 2 had poor disintegration properties because the 24-hour water absorbency of the waste paper pieces was less than 10%. [Industrial Applicability]

[0078] The bale manufacturing method of the present invention has the above-mentioned characteristics, and therefore the formed bale has excellent shape retention and also has excellent repulpability.

Claims

1. The method includes a molding step of compressing and molding waste paper pieces having at least a resin layer and a paper base layer to obtain a bale, The basis weight of the waste paper piece is 100 g / m ２ That's all. The content of the sizing agent in the paper base layer of the waste paper piece is 0.2% by mass or more and 2.1% by mass or less, The 24-hour water absorption of the waste paper pieces is 15% or more and 85% or less. How the veil is manufactured.

2. The method for manufacturing a bale according to claim 1, wherein the folding strength of the waste paper pieces is 20 gf or more and 350 gf or less.

3. The median area of ​​the waste paper pieces is 20 cm ２ More than 200cm ２ 3. The method for producing a veil according to claim 1 or 2, wherein:

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

5. A method for manufacturing a veil as described in claim 1 or 2, wherein the resin constituting the resin layer in the waste paper pieces is one or more selected from polyolefins, ethylene-vinyl alcohol copolymers (EVOH), and ethylene-methyl methacrylate copolymers (EMMA).

6. A method for manufacturing a veil as described in claim 1 or 2, wherein the basis weight of the resin layer in the waste paper pieces is 5 g / m 2 or more and 120 g / m 2 or less.

7. A method for manufacturing a bale as described in claim 1 or 2, wherein the basis weight of the paper base layer in the waste paper pieces is 80 g / m 2 or more and 400 g / m 2 or less.

8. The method for producing a bale according to claim 1 or 2, wherein the waste paper pieces further have a metal layer.

9. Bale forming pressure: 500 kN / m ２ More than 2500kN / m ２ 3. The method for producing a veil 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 forming the bale.

11. 3. The method for producing a bale according to claim 1 or 2, further comprising a washing step of washing the waste paper or waste paper pieces before forming the bale.

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