Cutlery and its manufacturing method

Abstract

To provide disposable cutlery that is made without using any plastic.SOLUTION: Disposable cutlery includes: a head part coming into contact with a food; a neck part continuing to the head part; and a handle part continuing to the neck part and to be griped. The disposable cutlery is formed of a sheet material which is made by papermaking pulp fibers and part or the whole of the sheet material is compressed and molded by pressing process.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention is a cutlery such as a spoon, a fork, and a knife. and its manufacturing method Regarding. [Background technology]

[0002] Disposable cutlery, which is intended to be discarded after one or a few uses, is used in various food and beverage service locations, such as food courts in commercial facilities, fast food shops, take-out bento shops, food service services on airplanes, food delivery and catering events, etc. Such disposable cutlery is required to be convenient and low-cost, as most of it is provided free of charge.

[0003] For this reason, plastic cutlery is widely used because it is easy to mold into the same shape as high-quality non-disposable cutlery made of metal or the like, and is inexpensive and lightweight (see Patent Document 1).

[0004] On the other hand, in recent years, marine pollution caused by microplastics has attracted attention, and a move away from plastic is progressing worldwide for environmental protection reasons. In Japan, the "Act on Promotion of Resource Recycling Related to Plastics" has been enacted, which, for example, requires certain businesses to reduce the use of disposable plastic products. Furthermore, this "Act on Promotion of Resource Recycling Related to Plastics" designates cutlery such as forks, spoons, and knives used in certain industries, such as accommodation, restaurants, and takeout and delivery food services, as "specified plastic-containing products," and there is a growing demand for a move away from plastic in cutlery.

[0005] The technology of replacing plastic cutlery with natural materials other than plastic is disclosed in Patent Documents 2, 3, and 4 below. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2017-524498 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-249963 [Patent Document 3] Patent Publication No. 2021-29926 [Patent Document 4] Patent Publication No. 2021-29924 Summary of the Invention [Problem to be solved by the invention]

[0007] The technology of Patent Document 2 forms a container for storing food by folding and adhering a sheet-shaped material, and therefore has the advantage that it can be manufactured by procuring and processing a pre-formed sheet material. However, since it does not have the curved design of molded plastic cutlery or non-disposable metal cutlery, the feel when placed in the mouth, etc., is significantly different from that of plastic cutlery.

[0008] On the other hand, the technologies of Patent Documents 3 and 4 use pulp molding technology to give the parts that go into the mouth a curved design like metal cutlery, and the surface is smooth, making the feel when placed in the mouth similar to that of plastic cutlery.

[0009] However, the pulp molding techniques of Patent Documents 3 and 4 involve directly molding wet pulp in a slurry state, so production requires equipment for handling wet pulp, making the manufacturing process and management more complicated than the technique of Patent Document 2, which can be used to manufacture from sheet material.In addition, with pulp molding techniques, it is difficult to increase the density and water resistance of the molded product because wet pulp is molded.

[0010] Therefore, the main objective of the present invention is to develop a cutlery that uses natural materials as the main raw material, yet has the same design and feel as conventional plastic disposable cutlery, is easy to manufacture as it can be manufactured from sheet material, and is also sufficiently water-resistant. and its manufacturing method The purpose is to provide [Means for solving the problem]

[0011] The first solution to the above problem is Disposable cutlery, The food container has a head portion that comes into contact with food, a neck portion that is connected to the head portion, and a handle portion that is connected to the neck portion and is used for holding the food, The head, neck and handle are , Shi It has a laminated structure in which a sheet material is laminated, The head portion has one edge One The blade portion is tapered toward one edge, and the one edge is formed by the edge of a single sheet material. This is a disposable cutlery characterized by the following.

[0012] The second method is The disposable cutlery according to the first aspect contains a siloxane compound.

[0013] The third method is The disposable cutlery according to the first or second means contains 90 to 100 mass% of softwood kraft pulp and hardwood kraft pulp as pulp fibers, and the blending ratio of softwood kraft pulp to hardwood kraft pulp is 5:95 to 30:70.

[0014] The fourth method is the one edge The density at 1.0 g / cm 3 The above is the disposable cutlery according to the first to third means.

[0015] The fifth method is The device has a head portion having a dish shape or a portion curved at least toward the tip end, a neck portion connected to the head portion and narrower than the head portion, and a handle portion having the same width as the neck portion or wider than the neck portion, At least the head portion and the neck portion are formed by press working, The neck portion is formed into a curved cross section, and the ratio of the cross-sectional curvature radius to the width is 1:0.4 to 1:0.8. The disposable cutlery relates to the first to fourth means.

[0016] The sixth method is The knife has a head portion having a blade portion that becomes thinner toward one edge, a neck portion connected to the head portion, and a handle portion connected to the neck portion, The head portion, neck portion, and handle portion are formed by laminating multiple sheets of sheet material, At least the blade portion is formed by press working so as to be tapered toward one edge. This is disposable cutlery according to the first to fourth means. The seventh method is The container has a head portion that comes into contact with food, a neck portion that connects to the head portion, and a handle portion that connects to the neck portion and is used for holding the food. The head portion, neck portion, and handle portion have a laminated structure in which a plurality of separate sheet materials made of pulp fiber are laminated together, The head portion is a blade portion in which one edge is tapered toward the other edge by press working, and the one edge is formed by the edge of a single sheet material. This is a method for manufacturing disposable cutlery. [Effects of the Invention]

[0017] According to the present invention, it is possible to produce cutlery that is made primarily from natural materials, yet has the same design and feel as conventional plastic disposable cutlery, and furthermore, it can be produced from sheet material, making it easy to manufacture, and it is also sufficiently water-resistant. and its manufacturing method The purpose is to provide [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a front view illustrating the cutlery according to the present embodiment. [Figure 2] 1 is a cross-sectional schematic diagram of multilayer paper according to an embodiment of the present invention. [Figure 3] 1A and 1B are front, side and cross-sectional views of a spoon according to an embodiment of the present invention. [Figure 4] 1A and 1B are front, side and cross-sectional views of a fork according to an embodiment of the present invention. [Figure 5] 1A and 1B are front, side and cross-sectional views of a knife according to an embodiment of the present invention. [Figure 6] 10A and 10B are diagrams for explaining a locking structure according to the present embodiment. [Figure 7] 10A and 10B are diagrams for explaining a method for measuring the bending strength of cutlery according to the present embodiment. [Figure 8] FIG. 10 is a diagram for explaining the results of bending strength measurement of the cutlery according to the present embodiment. [Figure 9] 10A and 10B are diagrams for explaining the results of other bending strength measurements of the cutlery according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, embodiments of the present invention will be described in detail below with reference to Figures 1 to 9. However, the present invention is not limited to these embodiments.

[0020] The disposable cutlery 1 according to this embodiment is intended to be disposed of after one or several uses, for example, at various food and beverage service locations, such as food courts in commercial facilities, fast food restaurants, takeout bento shops, in-flight food and beverage services, food delivery, and catering events. The disposable cutlery 1 according to this embodiment has a head portion 11 that mainly comes into contact with food, a neck portion 12 connected to the head portion 11, and a handle portion 13 connected to the neck portion 12 and mainly used for gripping and manipulating, and particularly includes a spoon 10, a fork 20, and a knife 30, as shown in FIG. 1 . Other examples of disposable cutlery include lotus spoons, muddlers, slotted spoons, etc.

[0021] The disposable cutlery 1 of this embodiment is characterized by being formed from a sheet material made from pulp fiber, and a portion or all of the pulp fiber sheet material is pressed in the thickness direction to form the cutlery. That is, the entire cutlery is formed from a sheet material made from pulp fiber, and a mold pre-formed to the partial or entire shape of the cutlery 1, such as the spoon 10, fork 20, or knife 30, is pressed against the sheet material in the thickness direction to compress the cutlery, thereby transferring the mold shape to the sheet material. Of course, the cutlery may be shaped into a desired shape by punching, cutting, or the like after pressing. Alternatively, the cutlery may be formed by increasing the thickness of a portion or all of the cutlery by, for example, laminating another sheet material that has not been pressed in the thickness direction on the pressed cutlery. Preferably, the entire cutlery is pressed in the thickness direction to form the cutlery, since this allows for high press pressure. In the cutlery 1 having the head 11, neck 12, and handle 13, if the cutlery 1 is a spoon 10 or a fork 20, it is desirable that at least the head 11 and neck 12 are formed by pressing, and it is particularly desirable that the entire cutlery including the head 11, neck 12, and handle 13 be formed by pressing. Furthermore, if the cutlery 1 is a knife 30, it is desirable that at least the edge portion of the head 11 that will become the blade be formed by pressing. Furthermore, the disposable cutlery 1 of this embodiment may be formed by pressing a plurality of laminated sheet materials, but it is preferable that only a single sheet material be formed by pressing, as there is no risk of peeling between the layers.

[0022] Conventional pulp molding technology, like the casting technology used in metal molding, involves pressing a fluid raw material containing pulp fibers into a mold and compressing it to form a bond. While this technology facilitates the formation of complex shapes, it is difficult to achieve high density. Furthermore, because the molded product lacks fiber orientation, it is rigid and weak, prone to breakage and cracking. The cutlery of this embodiment does not press a fluid raw material, as in the forging technology used in metal molding. Instead, it is formed by pressing a sheet material that has been dried once to form hydrogen bonds and has a fixed fiber orientation in the thickness direction, as in the forging technology used in metal molding. This results in a highly compacted product, and despite its thinness, it possesses appropriate plastic-like toughness and flexibility, providing sufficient strength for use. Furthermore, compared to cutlery made using conventional pulp molding technology, it is possible to increase strength while reducing thickness, and to achieve a smooth surface. This allows for the cutlery to be molded into shapes similar to those of high-quality metal cutlery, which have smooth curves and surfaces, and provides an excellent mouthfeel during use. Furthermore, it has the advantage of being easy to manufacture, as it does not require the fluid pulp slurry to be sieved during production.

[0023] Furthermore, the cutlery 1 of this embodiment is formed not from plastic but from a sheet material made from paper-made pulp fibers, thereby achieving a plastic-free society. From the perspective of achieving a plastic-free society, it is desirable that the cutlery 1 of this embodiment is not laminated with plastic made from a non-biodegradable resin, and it is particularly desirable that it is not laminated with plastic. Furthermore, because the cutlery 1 of this embodiment is an aggregate of pulp fibers, it will not shatter in the mouth even when chewed with teeth during use, making it sufficiently safe to use.

[0024] The bending strength of the cutlery 1 of this embodiment is not necessarily limited, as the required bending strength varies depending on the shape and use of the cutlery. However, it is desirable that the bending load at a bending deflection of 15 mm be 0.5 N or more in a two-point bending load test performed using a composite material testing machine (10 kN) Model 5966 or its equivalent. In this two-point bending test, as shown in FIG. 7, the handle 13 of the cutlery 1 is fixed to a support base 80A, and the center of the head 11 of the cutlery 1 is used as the push-in position. For example, if the cutlery 1 is a spoon 10 as shown in FIG. 7, the push-in position is the bottom of the bowl. The holding length L20 from the rear end of the cutlery to the end of the support base is not limited by the type or shape of the cutlery 1, but should be 25 to 30% of the cutlery's overall length. However, the cutlery should be set so that the narrowest point of the neck 12 is beyond the wire end 80t of the support base 80A. Measurements were performed with a small load of 500 N, a pressing speed of 40 mm / min, and a semicircular indenter 81. The measurement sample was set with the front side facing upward for spoons 10 and forks 20, and with the side facing upward for knives 30. A single curry spoon or tablespoon typically weighs approximately 15 to 30 g. When handling cutlery 1, such as spoons 10 and forks 20, the neck 12 or its vicinity is supported by fingers or other supports. Therefore, using this measurement method without supporting the neck, a bending load of 0.5 N or greater at a bending deflection of 15 mm can be considered to have particularly favorable strength sufficient for use with typical cutlery handling techniques. Furthermore, the cutlery of this embodiment preferably has a bending deflection of 2 N or greater at a bending deflection of 30 mm. Even with a relatively large table spoon-like shape, the cutlery has high flexibility, significantly reducing the risk of breakage or damage during use and providing high safety.

[0025] On the other hand, the cutlery 1 of this embodiment preferably has water resistance of 3 minutes or more, more preferably 5 minutes or more, although this is not necessarily limited to this. Here, water resistance means that the layers do not separate or disintegrate even when completely immersed in water. However, it is particularly desirable that the strength in the above-mentioned two-point bending load test, i.e., a bending load of 0.5 N or more at a bending deflection of 15 mm, is maintained even after immersion for 5 minutes.

[0026] Furthermore, the cutlery 1 according to this embodiment preferably contains a siloxane compound. It is more preferable that the siloxane compound be contained at least in the pressed portion, and particularly preferably throughout the entire cutlery. The inclusion of a siloxane compound increases rigidity, strength, water resistance, and surface smoothness due to siloxane bonds. It is preferable that the siloxane compound be contained at least in a range including the head portion 11, which is likely to come into contact with food and moisture in the oral cavity and is likely to come into contact with the oral cavity and lips, and the neck portion 12, which is likely to be twisted or subjected to force during operation. The effects of the inclusion of the siloxane compound on improving rigidity, strength, water resistance, and surface smoothness are easily noticeable. It is preferable that the siloxane compound be contained throughout the entire cutlery.

[0027] The siloxane compound is not necessarily limited as long as it has a siloxane bond, but since cutlery 1 may come into contact with food or be placed in the oral cavity, it is desirable that the siloxane compound be non-toxic or low-toxic to living organisms. To incorporate the siloxane compound into cutlery 1, the siloxane compound may be applied to cutlery 1, or an appropriate alkoxysilane solution or alkoxysilane solution-processed product may be impregnated into a sheet material before molding, followed by heating or pressing. In this way, the siloxane compound is incorporated into the pulp fibers by bonding to them or coating them.

[0028] Here, the cutlery 1 of this embodiment is formed by pressing a sheet material. However, the pressing pressure and pressing speed can be varied as appropriate depending on the type and shape of the sheet material and the cutlery, and are not necessarily limited. However, to compact the sheet material in the thickness direction and achieve sufficient strength, it is preferable to compress the sheet material using a pressing pressure of 60 tons or more, more preferably 80 tons or more, and particularly preferably 100 tons or more. The upper limit of the pressing pressure should be set within a range that does not cause breakage of the sheet material, but considering that the sheet material is made from pulp fibers, the upper limit is approximately 200 tons. Furthermore, when using such high pressing pressures for the cutlery 1 of this embodiment, it is preferable to press the entire cutlery 1 rather than pressing only a portion of it, particularly in terms of ease of manufacture and strength. Therefore, the cutlery 1 of this embodiment may be formed by pressing a single sheet of material, compressing it, and then partially bonding or crimping a non-pressed sheet material to the compressed and molded piece. When performing the press working, the sheet material may be heated during the press working, or may be moistened to facilitate deformation. A solution containing the above-mentioned siloxane compound or a solution containing a substance that is a precursor to the siloxane compound may be used as a moistening agent. The heating temperature, etc., during heating are not necessarily limited.

[0029] The cutlery 1 of this embodiment preferably has a basis weight of 700 g / m 2 More preferably, 850 g / m 2 More preferably, 950 g / m 2 The basis weight is a value measured in accordance with "Paper and paperboard - Basis weight measurement method" described in JIS P 8124 (2011). The preferred density of the cutlery 1 of this embodiment is 0.70 g / cm 3 or more, preferably 0.98 g / cm 3 More preferably, 1.1 g / cm 3 In particular, the density of the pressed part is preferably 1.0 g / cm 3 More preferably, 1.2 g / cm 3The density is calculated by (basis weight) / (paper thickness). The cutlery 1 of this embodiment can be said to have a sufficiently high density. In particular, with the above basis weight and this density, the cutlery is compacted to an appropriate mass, and although thin, has appropriate plastic-like stickiness and flexibility, resulting in sufficient strength for use. The thickness is not necessarily limited, but the thickness of the pressed portion per sheet is 1.5 mm or less, preferably 1.35 mm or less, and particularly preferably 1.0 mm or less. The paper thickness is a value measured in accordance with "Paper and paperboard - Test methods for thickness and density" described in JIS-P8118 (2014).

[0030] The pulp fibers constituting the cutlery 1 are not necessarily limited, but preferred constituent pulp fibers are softwood kraft pulps such as unbleached softwood kraft pulp (NUKP), semi-bleached softwood kraft pulp (NSBKP), and bleached softwood kraft pulp (NBKP), and hardwood kraft pulps such as unbleached hardwood kraft pulp (LUKP), semi-bleached hardwood kraft pulp (LSBKP), and bleached hardwood kraft pulp (LBKP). Other pulps may be used in combination with various known pulps, including chemical pulps such as recycled paper pulp, hardwood sulfite pulp, and softwood sulfite pulp, as well as pulps produced chemically or mechanically from non-wood fibers such as kenaf, hemp, and reed. However, because the cutlery 1 will come into contact with food and be placed in the mouth, it is preferable that it be made of 100% virgin pulp and contain no recycled paper pulp. Furthermore, since these are virgin pulps, and since it is easy to achieve both the appearance and strength of the processed product, it is desirable that the softwood kraft pulp and hardwood kraft pulp account for 90 to 100% by mass. In this case, the blending ratio of softwood kraft pulp to hardwood kraft pulp is desirably 5:95 to 30:70. By increasing the blending ratio of hardwood kraft pulp, which has a short fiber length, it is easy to compact it by pressing, and it is easy to develop strength and to improve the surface texture. Furthermore, since it is bleached pulp and has high whiteness, it is particularly preferable to use softwood bleached kraft pulp and hardwood bleached kraft pulp, as this results in cutlery 1 with a design that has a clean and hard feel.

[0031] The sheet material made from pulp fibers according to this embodiment may be dry-processed paper or wet-processed paper. Preferably, the paper is made from a pulp slurry by wet-processing, and has a machine direction (MD) and a cross direction (CD). Such paper has fiber orientation, making it easy to increase its strength. In particular, in cutlery 1 made by pressing a sheet material with such fiber orientation, it is desirable, although not necessarily limited, that the longitudinal direction from the head portion 11 side to the handle portion 13 side coincide with the machine direction (MD) of the paper. By aligning the machine direction (MD) and the longitudinal direction of the paper, the cutlery 1 becomes flexible and less likely to break when the head portion 11 is operated by holding the handle portion 13.

[0032] A particularly preferred sheet material according to this embodiment is multilayer paper 50 having three or more paper layers. The cutlery 1 of this embodiment is particularly preferably constructed using this multilayer paper 50 as the sheet material, and also preferably containing a siloxane compound. As shown in FIG. 2 , the multilayer paper 50 is composed of multiple laminated paper layers 51 and 52, making it easier to increase strength when compacted in the thickness direction than single-layer paper. Furthermore, the properties of each layer of the multilayer paper 50 can be varied, making it easy to maintain high density while maintaining elasticity and water resistance. For example, combining a pair of surface layers 51, which are water-resistant but stiff and prone to breaking, with a flexible middle layer 52 results in excellent water resistance, strength, and durability. Furthermore, in the disposable cutlery 1 according to this embodiment, the sheet material is compression-molded by pressing in the thickness direction, i.e., the layer stacking direction of the multilayer paper 50, thereby easily maintaining the properties of each layer of the multilayer paper 50. Therefore, sufficient strength is easily exhibited even when the paper has a shape similar to that of plastic disposable cutlery 1, such as the spoon shown in FIG. 3 or the fork shown in FIG. 4, in which the head portion 11 and handle portion 13 are connected via a narrow neck portion 12, making it easy to achieve a thin, long shape overall. In particular, the neck portion 12 is easily flexible, making it easy to achieve a feel similar to that of plastic disposable cutlery 1. The multilayer paper 50 can be manufactured by multi-layer papermaking. The multilayer paper 50 may be commercially available, such as Elipla Paper manufactured by Dainichi Paper Co., Ltd.

[0033] The multilayer paper 50, which is a preferred sheet material according to this embodiment, desirably has a tensile strength of 50 kN / m or more in both the longitudinal and transverse directions as measured in accordance with JIS P 8113 (2006). This tensile strength makes it easy to ensure sufficient strength in the non-press-processed areas and after shaping by press processing.

[0034] Furthermore, the multilayer paper 50, which is a preferred sheet material according to this embodiment, has a Taber stiffness measured in accordance with JIS P 8125 (2000) of 125 mN m or more, preferably 150 mN m or more, in the machine direction, and 40 mN m or more, preferably 60 mN m or more, in the cross direction. This multilayer paper 50 has sufficient stiffness and strength, and it is easy to ensure sufficient strength in the non-press-processed areas and after forming by press processing.

[0035] Furthermore, the multilayer paper 50 has a Z-axis strength of 400 kN / m as measured in accordance with JAPAN TAPPI Paper and Pulp Testing Method No. 18-1:2000. 2 More than 450kN / m 2 It is desirable that the above conditions are met. It has excellent formability by press working, and is easy to manufacture by punching such as Thomson working before or after press working, or cutting with a cutting plotter or the like.

[0036] The number of layers in the multilayer paper 50, which is a preferred sheet material according to this embodiment, is not limited, but is preferably five to nine layers, with three or more middle layers 52, especially five. In particular, the form shown in FIG. 2 has three middle layers 52. It is believed that when the total number of middle layers 52 is three or more, the multilayer paper 50 is more likely to exhibit strength and durability. From the perspective of maintaining interlayer strength, the upper limit for the total number of middle layers 52 is preferably seven or less. Furthermore, three to seven layers facilitate operation while maintaining interlayer strength when using a cylinder-type multi-cylinder papermaking machine.

[0037] Here, the basis weight of the multilayer paper 50, which is a preferred sheet material according to this embodiment, is preferably 700 g / m 2 , similar to the cutlery 1 after molding. 2 More preferably, 850 g / m 2 More preferably, 950 g / m 2That's all. Multilayer paper 50 with this basis weight can be easily compacted in the thickness direction to achieve sufficient rigidity and strength, and can be made to have a usability similar to that of disposable plastic cutlery. There is no upper limit to the basis weight of multilayer paper 50, but there is a risk that creases may easily occur due to the calender rolls or the like during papermaking. From this point of view, the upper limit is set to 1400 g / m 2 is preferred, and 1240 g / m 2 is more preferable. The thickness of the multilayer paper is preferably 900 μm or more and 1,500 μm or less, and more preferably 1,000 μm or more and 1,350 μm or less. If the multilayer paper 50 having this thickness is pressed to a thickness of 1.5 mm or less, preferably 1.35 mm or less, and particularly preferably 1.0 mm or less, it is easy to achieve the strength required for the cutlery 1 of this embodiment. The basis weight is a value measured in accordance with "Paper and paperboard - Basis weight measurement method" described in JIS P 8124 (2011), and the thickness is a value measured in accordance with "Paper and paperboard - Thickness and density test method" described in JIS-P8118 (2014).

[0038] The basis weights of the surface layer 51 and the middle layer 52 in the multilayer paper 50, which is a preferred sheet material according to this embodiment, can be adjusted within the range of the basis weight of the entire sheet material described above, and are not particularly limited. Preferably, the basis weight of the surface layer 51 is 60.0 g / m per layer. 2 More than 250.0g / m 2 Below 130-150g / m 2 The basis weight of the entire middle layer 52 is preferably 500 g / m 2 More than 900g / m 2 Below 650g / m 2 More than 800g / m 2The following is preferable. Furthermore, it is preferable that the ratio of the total basis weight of the pair of surface layers 51, 51 to the basis weight of the entire multilayer paper 50 is 20.0% or more and 35.0% or less. This is because the pair of surface layers 51 have high rigidity and the middle layer 52 has excellent flexibility. Furthermore, in multilayer paper 50, when the ratio of the total basis weight of the pair of surface layers 51 is in the above range, it has the property of being difficult to bend. A preferable multilayer paper 50 has a density of preferably 0.65 to 1.50 g / cm before compression molding by press working. 3 , more preferably 0.73 to 1.00 g / cm 3 , particularly preferably 0.76 to 0.96 g / cm 3 When the density of the multilayer paper 50 is within this range, it has a high basis weight and excellent rigidity, is less likely to break, and is more likely to have greater hardness and stiffness when formed by press processing.

[0039] The preferred pulp fibers constituting each layer of the multilayer paper 50 are similar to those constituting the cutlery 1 described above. While not necessarily limited, they are preferably softwood kraft pulps such as unbleached softwood kraft pulp (NUKP), semi-bleached softwood kraft pulp (NSBKP), and bleached softwood kraft pulp (NBKP), and hardwood kraft pulps such as unbleached hardwood kraft pulp (LUKP), semi-bleached hardwood kraft pulp (LSBKP), and bleached hardwood kraft pulp (LBKP). Other pulps may be used in combination with various known pulps, including chemical pulps such as recycled paper pulp, hardwood sulfite pulp, and softwood sulfite pulp, as well as pulps produced chemically or mechanically from non-wood fibers such as kenaf, hemp, and reed. However, because cutlery is used in applications where it comes into contact with food and is placed in the mouth, it is preferable that it be made of 100% virgin pulp and does not contain recycled paper pulp. Furthermore, since these are virgin pulps, and since it is easy to achieve both the appearance and strength of the processed product, it is desirable that the softwood kraft pulp and hardwood kraft pulp account for 90 to 100% by mass. In this case, the blending ratio of softwood kraft pulp to hardwood kraft pulp is desirably 5:95 to 30:70. By increasing the blending ratio of hardwood kraft pulp, which has a short fiber length, it is easy to compact it by pressing, and it is easy to develop strength and to improve the surface texture. Furthermore, since it is bleached pulp and has high whiteness, it is particularly preferable to use softwood bleached kraft pulp and hardwood bleached kraft pulp, as this results in cutlery 1 with a design that has a clean and hard feel.

[0040] From the perspective of eliminating plastics, the multilayer paper 50, which is a preferred sheet material according to this embodiment, is desirably made of only natural fibers, without any synthetic fibers, including plastics. Preferably, it is made of only pulp fibers.

[0041] Regarding the blend of pulp fibers in each layer of this multilayer paper 50, the mass ratio (%) of softwood kraft pulp to the hardwood kraft pulp in the surface layer 51 is preferably between 0 / 100 and 15 / 85. The surface layer contains a large amount of hardwood kraft pulp, which is rigid and easily densified, giving the surface layer high density and rigid properties, resulting in cutlery 1 with excellent strength. Along with the surface layer 51 having this blend, the middle layer 52 also preferably has a mass ratio (%) of softwood kraft pulp to the hardwood kraft pulp of between 15 / 85 and 35 / 65. By including a larger amount of softwood kraft pulp, which is more flexible than the surface layer, it becomes easier to compress and mold the cutlery 1 in the thickness direction during press processing, making it easier to form the cutlery 1 into the desired shape.

[0042] Furthermore, the multilayer paper 50, which is a preferred sheet material according to this embodiment, preferably contains at least one of a sizing agent and a paper strength agent as a papermaking additive. This makes it easy to adjust the strength to the desired level. The multilayer paper 50 can also contain various other additives within a range that does not impair the intended effects of the present invention. For example, polyvinyl alcohol, wax, etc. can be applied.

[0043] Examples of sizing agents include styrene-based sizing agents, alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), neutral rosin sizing agents, rosin sizing agents, and modified rosin emulsion sizing agents. Among these, rosin sizing agents and modified rosin emulsion sizing agents are preferred. The rosin sizing agent is not particularly limited. Examples of rosin-based substances include fortified rosins obtained by modifying rosins such as gum rosin, wood rosin, and tall oil rosin with α,β-unsaturated carboxylic acids or their anhydrides, such as fumaric acid, maleic acid, and acrylic acid, and rosin esters obtained by reacting rosins with polyhydric alcohols, such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and diglycerin. Rosin sizing agents also include emulsions of these substances alone or a mixture thereof, as well as emulsions of these substances emulsified alone and then mixed together. Furthermore, emulsions to which various polymers have been added to further improve sizing properties are also included.

[0044] Various known paper strength agents can be used, such as polyacrylamide resins, polyamide resins, polyamine resins, acrylic resins, melamine resins, urea resins, and polyamide-epichlorohydrin resins. Among these, it is preferable to use amphoteric paper strength agents. Examples of amphoteric polyacrylamides include copolymers of acrylamide with anionic monomers and cationic monomers, Mannich-modified copolymers of acrylamide with anionic monomers, and Hoffman degradation products. Amphoteric polyacrylamides, in particular, have a self-fixing function, so even if they are added in excess to improve inter-paper strength, they do not result in an excess of cations. Therefore, when used together with a modified rosin emulsion sizing agent, they can stably fix the sizing agent.

[0045] The amount of sizing agent added is preferably 0.5 kg / t or more and 5.0 kg / t or less in terms of solids. The amount of paper strength agent added is preferably 12 kg / t or more and 30 kg / t or less in terms of solids. Note that "kg / t" indicates the mass (kg) per ton of pulp. If the amount of sizing agent added is within this range, water resistance can be sufficiently improved, resulting in a multi-layer paper that is particularly suitable for cutlery use.

[0046] Furthermore, it is preferable that at least one of the above-mentioned sizing agents and paper strength agents be added as papermaking additives to each of the surface layer 51 and the middle layer 52 of the multilayer paper 50. In this case, the amount of sizing agent added to the surface layer 51 is preferably 0.5 kg / t to 5.0 kg / t in terms of solids. The amount of sizing agent added to the middle layer 52 is preferably 2.0 kg / t to 5.0 kg / t in terms of solids. The amount of paper strength agent added to each layer is preferably 12 kg / t to 30 kg / t in terms of solids. By setting the amount within this range, it is easy to achieve various paper strengths, such as interlaminar strength, suitable for cutlery.

[0047] Furthermore, a more preferred specific shape of the disposable cutlery 1 according to this embodiment will be further described using a spoon 10 as an example. Fig. 3 shows a table spoon 10, which is disposable cutlery according to this embodiment. In Fig. 3, (A) is a diagram showing a front view, (B) is a diagram showing a side view, and (C) is a diagram showing a cross-sectional view of the curved shape on the front side at positions (1) to (7) in (A).

[0048] The spoon 10 of this illustrated embodiment is formed by compressing and pressing a sheet material from the head 11 to the handle 13. The head 11, which comes into contact with food, is bowl-shaped with an open front, similar to common metal spoons and conventional disposable plastic spoons, so that it can scoop up various types of food, including solids, powders, and liquids.

[0049] Furthermore, in spoon 10 according to this embodiment, neck 12, which connects to head 11, is formed narrow and smoothly curved from head 11 when viewed from the front, and handle 13, which connects to neck 12, is the same width as neck 12 or wider than neck 12. Furthermore, the edges from head 11 to handle 13 are curved when viewed from the front and side, and the front and back are also curved, giving the spoon an overall shape similar to that of high-quality, streamlined, non-disposable cutlery made of metal or the like, and providing excellent design. However, spoon 10 according to this embodiment is not limited to this shape.

[0050] On the other hand, in the spoon 10 according to this embodiment, the neck 12, which connects to the head 11, is narrow and smoothly curved from the head 11 when viewed from the front. In particular, as shown in FIG. 3, the neck 12 is formed with a curved cross section that opens toward the front, with the ratio of the radius of curvature R1 to the width L1 being 1:0.4 to 1:0.8. A ratio of 1:0.4 to 1:0.75 is particularly preferable. Having a ratio of the radius of curvature R1 to the width L1 of the neck increases strength while allowing the spoon to be removed from a compression-molded mold. In general, a ratio of the radius of curvature R1 to the width less than 1:0.5 prevents the spoon from being removed from the mold. However, in the cutlery of this embodiment, the sheet material is made of paper-made rup fiber, and the curved surface flexes to open, allowing a ratio of less than 1:0.5. Compared to a neck portion 12 that is not curved in cross section, the bending strength of the head portion 11 when pressed from the front or back is improved. In particular, if the ratio of the radius of curvature of the cross section to the width is 1:0.4 to 1:0.8, the risk of the neck portion breaking during use, for example, during a typical operation of scooping food with a spoon, is significantly reduced.

[0051] The spoon of this embodiment is not limited to a specific size, but in the case of the tablespoon 10 shown in FIG. 3, the overall length L2 is 180 to 200 mm, the length L3 of the head portion 11 is 45.0 to 60.0 mm, the maximum width L4 of the head portion 11 is 35.0 to 45.0 mm,

[0052] The length L5 of neck portion 12 can be 40.0 to 50.0 mm, and the minimum width L6 of neck portion 12 can be 8.5 to 22.0 mm. This shape allows the spoon to have a feel similar to that of a commonly available disposable plastic tablespoon 10.

[0053] In the illustrated embodiment, the shape and size of the table spoon 10 have been described as an example, but when the cutlery of this embodiment is a spoon, it is not limited to this and can be of any appropriate size as long as it does not impair the effects of the present invention, and can be of any size and shape suitable for use as a serving spoon, dessert spoon, soup spoon, fish spoon, teaspoon, coffee spoon, demitasse spoon, ice cream spoon, etc. It may also be a spoon with a bifurcated or trifurcated tip, such as a melon spoon or strawberry spoon.

[0054] Furthermore, a more preferred specific shape of the disposable cutlery 1 according to this embodiment will be further described using the fork 20 as an example. Fig. 4 shows a table fork 20, which is the disposable cutlery 1 according to this embodiment. In Fig. 3, (A) is a diagram showing a front view, (B) is a diagram showing a side view, and (C) is a diagram showing a cross-sectional view of the curved shape on the front side at positions (1) to (7) in (A).

[0055] The fork 20 of this illustrated embodiment is formed by pressing and compressing a sheet material from the head 11 to the handle 13, just like the spoon 10. The head 11, which comes into contact with food, is shaped like a shallow bowl with an open front so that it can scoop up various types of food, such as solids, powders, or liquids, and the tip is shaped like a four-pronged comb so that it can pierce and hold food.

[0056] Furthermore, in the fork 20 according to this embodiment, similar to the spoon 10, the neck 12 connected to the head 11 is formed narrow and smoothly curved from the head 11 in front view, and the handle 13 connected to the neck 12 is the same width as the neck 12 or wider than the neck 12. Furthermore, from the head 11 to the handle 13, the edges are curved in front view and side view, and the surfaces are also curved, giving the fork 20 an overall shape similar to that of high-quality, streamlined, non-disposable cutlery made of metal or the like, resulting in excellent design. However, the fork 20 according to this embodiment is not limited to this shape.

[0057] On the other hand, like the spoon 10, the fork 20 according to this embodiment also has a neck 12 that connects to the head 11 and is narrow and smoothly curved from the head 11 when viewed from the front. As shown in FIG. 4, the neck 12 is curved in cross section, opening toward the front, with the ratio of the radius of curvature R2 of the cross section to its width L7 being 1:0.4 to 1:0.8. A ratio of 1:0.4 to 1:0.75 is particularly preferred. A neck 12 that is curved in cross section improves bending strength when the head 11 is pressed from the front or rear, compared to a neck 12 that is not curved. In particular, a ratio of the radius of curvature R2 of the cross section to its width being 1:0.4 to 1:0.8 significantly reduces the risk of the neck 12 breaking during use, for example, during the normal operation of stabbing food with the fork.

[0058] 4, the overall length L8 can be 180-200 mm, the length L9 of the head portion 11 can be 45.0-60.0 mm, the maximum width L10 of the head portion 11 can be 35.0-45.0 mm, the length L11 of the neck portion can be 40.0-50.0 mm, and the minimum width L12 of the neck portion can be 8.5-22.0 mm. This shape can provide a feel similar to that of a commonly available disposable plastic table fork 20.

[0059] In the illustrated embodiment, the shape and size of a table fork are described as an example, but when the cutlery of this embodiment is a fork, it is not limited to this and can be of any appropriate size as long as it does not interfere with the effects of the present invention. For example, it can be of a size and shape suitable for use as a service fork, dessert fork, fish fork, salad fork, fruit fork, cake fork, or small fork.

[0060] Furthermore, a more preferred specific shape of the disposable cutlery 1 according to this embodiment will be further described using the knife 30 as an example. Fig. 5 shows a table knife 30, which is the disposable cutlery 1 according to this embodiment. In Fig. 5, (A) is a diagram showing a rear view, (B) is a diagram showing a side view, and (C) is a diagram showing a cross-sectional view at positions (1) to (7) in (A).

[0061] The knife 30 of this embodiment shown in the drawings has a blade portion 11B in which one edge of the head portion 11 is pressed to taper toward that edge. Furthermore, in the knife 30 of this embodiment, one edge of the blade portion 11B is formed into a slightly bulging curved shape in side view, and the neck portion 12 connected to it is smoothly and continuously curved in side view and continues to the handle portion 13. The edge on the blade portion 11B side has an overall streamlined shape similar to that of high-quality, non-disposable cutlery made of metal or the like, resulting in an excellent design. However, the knife 30 of this embodiment is not limited to this shape.

[0062] Furthermore, the knife 30 of this embodiment is characterized in that the head portion 11, neck portion 12, and handle portion 13 are formed by stacking two sheets 30A and 30B. In particular, the sheet material is not pressed except for the pressed edge, resulting in an increased thickness compared to the blade portion 11B. The thickness of the non-pressed portion is not necessarily limited, but is between 1800 μm and 3000 μm. The number of laminated sheets is not necessarily limited, but is preferably 2 to 3. By forming the blade portion 11B, in which one edge of the head portion 11 is pressed to become thinner toward that edge, and further stacking sheet material in other portions, the risk of the knife breaking during use, for example, during a typical operation of cutting food with the knife, is significantly reduced. Although not shown, the edge of the blade portion 11B may be formed like a sawtooth. This makes it easier to cut fibrous materials such as meat.

[0063] While there are no specific limitations on the size of the knife of this embodiment, in the case of table knife 30 shown in Figure 4, the overall length L13 can be 180 to 200 mm, the length L14 of head portion 11 can be 90.0 to 110.0 mm, the maximum width L15 of head portion 11 can be 12.0 to 20.0 mm, the length L16 of handle portion can be 90.0 to 100.0 mm, and the width L17 of handle portion can be 15.0 to 25.0 mm. This shape can provide a feel similar to that of a commonly available disposable plastic table knife.

[0064] In the illustrated embodiment, the shape and size of a table knife are described as an example, but if the cutlery of this embodiment is a fork, it is not limited to this and can be of any appropriate size as long as it does not interfere with the effects of the present invention, and can be of a size and shape suitable for use as a dessert knife, fish knife, fruit knife, or butter knife, for example.

[0065] The cutlery of this embodiment may include a portion where non-pressed portions of sheet material are laminated together, as in the knife 30 shown in FIG. 4 . Furthermore, a portion where pressed portions of sheet material and non-pressed portions are laminated together may also be included. The method for joining the sheets together is not necessarily limited. As long as the effects of the present invention are not impaired, joining can be achieved using a joining method such as adhesives, crimping, rivet, eyelet, wedge, staple, or a locking structure also known as a coreless staple. Multiple joining methods may also be used in combination. Adhesives for joining may include starch, various modified starches, modified celluloses such as carboxymethyl cellulose, water-soluble polymer adhesives such as polyvinyl alcohol, and aqueous emulsion resins such as acrylic esters and vinyl acetate. Starch and cellulose-based natural materials are preferable in terms of environmental impact. Rivets and staples that form the rivets and eyelets used for joining should preferably be made of wood or metal, rather than plastic.

[0066] A preferred joining method is a locking structure, as shown in FIG. 5(A) and FIG. 5(B), which shows the cross-sectional view B-B thereof. This locking structure forms cut-out pieces 70, 70 by punching a portion of the front and back surfaces, and then presses the tip portions 70t, 70t into at least the adjacent layer to mechanically join the layers together. In this locking structure, a half-cut line may be formed at the same position as the edge 70e of the cut-out piece 70 in at least the adjacent layer in a plan view to facilitate insertion of the tip portion 70t. Specifically, this locking structure can be formed in multiple locations, such as the locking portion 40 on the knife 30 shown in FIG. 4, to integrate the sheet materials. Because the cutlery 1 of this embodiment uses a stiff paper sheet material, this locking structure can also join the layers together. This locking structure is also desirable because it does not require the use of additional components. However, as mentioned above, a mechanical locking structure, including this locking structure, may be used in combination with an adhesive. In this case, there is also the advantage that the amount of adhesive used can be reduced. [Example]

[0067] Next, spoons (Examples 1 to 7) were produced as cutlery according to the present invention, and their bending strength was measured. Examples 1 to 7 all had the shape shown in FIG. 3. The total length was 190 mm. The sheet material was a multi-layer paper (Elipla Paper manufactured by Dainichi Paper Co., Ltd., basis weight 1000 g / m) whose fiber raw material was 100% pulp fiber. 2 ) was used. The entire sample was pressed, and Example 1 was processed using a press pressure of 60 tons, Example 2 was processed using a press pressure of 80 tons, and Example 3 was processed using a press pressure of 110 tons, thereby varying the processing pressure. Examples 4 and 5 were processed using a press pressure of 110 tons and contained a siloxane compound. In Examples 4 and 5, the content of the siloxane compound was doubled compared to Example 4. Examples 6 and 7 were processed using a press pressure of 60 tons and contained a siloxane compound. In Examples 6 and 7, the content of the siloxane compound was doubled compared to Example 6.

[0068] The test method was a two-point bending load test using a composite material testing machine (10 kN) Model 5966. As shown in Figure 7, the sample was fixed so that the tip position 80t of the support stand 80A was 70 mm from the rear end of the cutlery. The narrowest part of the neck 12 was located forward of the tip position 80t. The indentation position was the bottom position of the bowl shape. The measurement was performed with a small load of 500 N, the indentation speed was 40 mm / min, and the radius R1 of the indenter 81 was 5 mm.

[0069] The measurement results for each example are shown in Figures 8 and 9. As shown in Figure 8, although Examples 1 to 3 were subjected to different press processing pressures, the bending load was 0.5 N or more at a bending deflection of 15 mm, and 2 N or more at a bending deflection of 30 mm, demonstrating sufficient strength for cutlery. Furthermore, as shown in Figure 9, it was confirmed that the strength was further increased by including a siloxane compound.

[0070] Next, a spoon (Example 8) and a fork (Example 9) as cutlery according to the present invention, and sheet materials in the shape of the cutlery before press processing (Comparative Examples 1 and 2) were prepared, and a sensory test was conducted in which subjects actually used them. The spoon according to Example 8 was the same as that of Example 3, and the fork according to Example 9 had the shape shown in FIG. 4, and the sheet material was made of multi-layer paper whose fiber raw material was 100% pulp fiber (Eripla Paper manufactured by Dainichi Paper Co., Ltd., basis weight 1000 g / m). 2 The shapes of Comparative Examples 1 and 2 were the same as those of Examples 8 and 9 before press processing, and the sheet material was a multi-layer paper (Eripura Paper manufactured by Dainichi Paper Co., Ltd., basis weight 1000 g / m) whose fiber raw material was 100% pulp fiber. 2 ) was used.

[0071] In the sensory test, participants freely tried the curry roux, white rice, and fried chicken from the takeout "Crispy Chicken Curry" sold by curry specialty store "Curry House CoCo Ichibanya" (operated by Ichibanya Co., Ltd.) using the spoons and forks of Examples 8 and 9 and the spoons and forks of Comparative Examples 1 and 2, and evaluated the usability. The evaluation criteria were based on free evaluation criteria, particularly focusing on strength, mouthfeel, and operability, with easy to use being rated as "good" and difficult to use being rated as "bad." The number of subjects was N=5. As a result of the test, all five subjects rated Examples 8 and 9 as easy to use with "good," and Comparative Examples 1 and 2 as difficult to use with "bad." From these results, it can be said that the cutlery according to the present invention can be used satisfactorily.

[0072] As described above, the present invention provides cutlery that uses natural pulp fiber as the main raw material, yet achieves the same design and feel as conventional plastic disposable cutlery, and furthermore, can be manufactured from sheet material, making it easy to manufacture, and is also sufficiently water-resistant. [Explanation of symbols]

[0073] 1...cutlery, 10...spoon, 20...fork, 30...knife, 30A, 30B...sheet material, 11...head portion, 12...neck portion, 13...handle portion, 50...multilayer paper, 51...surface layer, 52...middle layer.

Claims

1. The food container has a head portion that comes into contact with food, a neck portion that is connected to the head portion, and a handle portion that is connected to the neck portion and is used for holding the food, The head portion, neck portion, and handle portion have a laminated structure in which sheet materials are stacked, The head portion has a blade portion whose one edge is tapered toward the other edge, and the one edge is formed by the edge of a single sheet material. Disposable cutlery characterized by:

2. 2. The disposable cutlery according to claim 1, which contains a siloxane compound.

3. 3. The disposable cutlery according to claim 1 or 2, wherein the pulp fibers comprise 90 to 100 mass% of softwood kraft pulp and hardwood kraft pulp in total, and the blending ratio of softwood kraft pulp to hardwood kraft pulp is 5:95 to 30:

70.

4. The density at the one edge is 1.0 g / cm ３ The disposable cutlery according to any one of claims 1 to 3.

5. Disposable cutlery according to any one of claims 1 to 4, wherein a plurality of separate sheet materials are laminated and integrated by at least one of an interlocking structure that mechanically joins the layers together by forcing the tip of a cut piece of a sheet material having the cut piece formed by punching into the adjacent layer of sheet material, and adhesive bonding.

6. Disposable cutlery as described in claim 1, wherein one edge portion is a compression molded portion.

7. A food container having a head portion that comes into contact with food, a neck portion that connects to the head portion, and a handle portion that connects to the neck portion and is used for holding the food, The head portion, neck portion, and handle portion have a laminated structure in which a plurality of separate sheet materials made of pulp fiber are laminated together, The head portion is a blade portion in which one edge is tapered toward the other edge by press working, and the one edge is formed by the edge of a single sheet material. A method for manufacturing disposable cutlery.

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