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Abstract

Provided is a sheet capable of preventing rolling of a packaging item such as a product to be packed in a container.　The present technology provides a sheet on which protrusions are scattered, wherein, when an object is pressed against the protrusions and the protrusions are crushed, the protrusions maintain a form such that all of the protrusions are crushed by the object or a form such that some of the protrusions are crushed thereby, and the object is secured by the protrusions having the crushed shape and / or the protrusions maintaining an uncrushed, original shape.

Description

[Technical Field]

[0001] This technology relates to sheets. [Background technology]

[0002] To facilitate the transportation of goods and products, and to prevent damage during transport, cushioning material is placed in the gaps between the goods or products and their containers during packaging. Traditionally, cushioning materials used in packaging have included synthetic resin bubble wrap with multiple air-filled hollow sections, air cushions, loose-leaf cushioning material, kraft paper, mirror mat, paper cushion, and stretch film. Synthetic resin bubble wrap can be bulky and difficult to handle when storing or disposing of it due to the air-filled hollow sections. In addition, air cushions, loose-leaf cushioning material, kraft paper, mirror mat, paper cushion, and stretch film inevitably generate a lot of waste, requiring effort in purchasing materials and securing storage space. To reduce material waste, a corrugated cardboard packaging container equipped with a retaining member to hold goods or products in place inside the container has been proposed (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Utility Model Registration No. 3160273 Gazette [Overview of the project] [Problems that the invention aims to solve]

[0004] However, in the technique of Patent Document 1, it is necessary to prepare a pressing member adapted to the size and shape of a commodity or product, and since the pressing member is made of cardboard, there is a problem that the commodity or product rolls laterally during transportation. Further, in recent years, there has been a demand for fixing and packing various types of commodities with different shapes and sizes into a container on the same packing line, but the technique of Patent Document 1 has a problem that packing on the same packing line is difficult because a pressing member adapted to the commodity is required. The present technology aims to provide a sheet capable of preventing lateral rolling of objects to be packed such as commodities to be packed in a container. [Means for Solving the Problem]

[0005] The present technology provides a sheet with scattered convex portions, wherein when an object is pressed against the convex portions and the convex portions are crushed, the convex portions maintain a shape in which all of the convex portions are crushed or a shape in which a part of the convex portions are crushed by the object, and the object is fixed by the crushed convex portions and / or the convex portions maintaining the original uncrushed shape. The sheet may be formed from a resin composition containing a biomass material and a thermoplastic resin. In the sheet, the cross-sectional shape of the convex portions may be circular. In the sheet, the cross-sectional shape of the convex portions may be rectangular. In the sheet, the cross-sectional shape of the convex portions may be polygonal. In the sheet, the convex portions may be single-stage convex portions. In the sheet, the convex portions may be multi-stage convex portions. When the object is pressed against the multi-stage convex portions, the sheet allows the convex portions at the step contacting the object to be easily crushed and maintains the shape crushed by the object. The sheet can return to the shape of the convex portion before being crushed by applying an external force from the back side of the crushed convex portion. When the sheet returns to the shape of the convex portions before being crushed, the object is pressed against the convex portions. When the convex portions are crushed, the convex portions maintain a shape in which all of the convex portions are crushed or a shape in which a part of the convex portions are crushed by the object, and the object can be fixed by the crushed convex portions and / or the convex portions maintaining the original uncrushed shape. The present technology also provides a packaging material including the sheet. [Advantageous Effects of Invention]

[0006] According to the present technology, a sheet capable of preventing rolling of an object to be packaged such as a product packaged in a container can be provided. [Brief Description of Drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing an example of a sheet with scattered convex portions according to the present embodiment. [Figure 2] FIG. 2 is a plan view of a sheet 10 with scattered convex portions according to the present embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2 [Figure 4] FIG. 4 is a perspective view of a sheet 40 with scattered convex portions according to the present embodiment. [Figure 5] FIG. 5 is a perspective view of a sheet 50 with scattered convex portions according to the present embodiment. [Figure 6] FIG. 6 is a plan view of a sheet 50 with scattered convex portions according to the present embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line A-A in FIG. 6 [Figure 8] FIG. 8 is a plan view photograph showing a state where an object P is pressed against convex portions 51 of the sheet and the convex portions 51 are crushed. [Figure 9] FIG. 9 is a perspective photograph showing a state where an object P is pressed against convex portions 51 of the sheet and the convex portions 51 are crushed. [Figure 10] FIG. 10 is a perspective photograph showing the state of convex portions 51 after an object P is pressed against the convex portions 51 of the sheet, the convex portions 51 are crushed, and then the object P is removed. [Figure 11] This is a perspective view of the sheet 60 with scattered protrusions according to this embodiment. [Figure 12] This is a plan view of the sheet 60 with scattered protrusions according to this embodiment. [Figure 13] This is a cross-sectional view along line AA in Figure 12. [Figure 14] This embodiment is a two-layer sheet composed of layer A and layer B. [Figure 15] This embodiment is a three-layer sheet composed of layer A, layer B, and layer A. [Figure 16] This embodiment is a three-layer sheet composed of layer A, layer B, and layer C. [Figure 17] This is a perspective view showing the object P being pressed against sheet 60. [Figure 18] This is a cross-sectional view along line AA in Figure 17. [Figure 19] This is a photograph taken from the back side of the surface of the sheet 50 that contacts the object, showing the completely flattened protrusion 51A after pressing the object against it. [Figure 20] This is a photograph of the back side of the crushed protrusion 51A, after the crushed area has been pressed back with a finger to restore its shape. [Figure 21] This is a photograph of the convex portion 51A after its shape has been restored by a finger. [Figure 22] This is an oblique photograph of sheet 50 that was obtained. [Figure 23] This photograph shows how a rectangular metal object P is pressed against the sheet 50, crushing the convex portions 51 scattered on the surface of the sheet 50. [Figure 24] This is a magnified photograph showing the relationship between the rectangular metal P and the protruding part. [Figure 25] This photograph shows the result of pressing a wrench S against the sheet 50, crushing the protrusions 51 scattered on the surface of the sheet 50. [Figure 26] This is a magnified photograph showing the relationship between the wrench S and the protrusion. [Modes for carrying out the invention]

[0008] Preferred embodiments of the present technology will be described below. The embodiments described below are representative embodiments of the present technology, and the scope of the present technology is not limited to these embodiments. In this specification, numerical ranges indicated using "~" represent ranges that include the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step may be replaced with the upper or lower limit of a numerical range in another step. Unless otherwise specified, the materials exemplified in this specification can be used individually or in combination of two or more.

[0009] This technology will be explained in the following order. 1. First Embodiment (Example of a Sheet) (1) Sheet structure (2) Method for manufacturing sheets (3)Applications 2. Examples

[0010] 1. First Embodiment (Example of a Sheet)

[0011] (1) Sheet structure The configuration of the sheet according to this embodiment will be described below with reference to the drawings. In this specification, the "direction perpendicular to the object when it is placed on a horizontal surface with the surface on which it is placed facing upwards" is referred to as the "thickness direction," and the "any direction in a plane perpendicular to the thickness direction" is referred to as the "plane direction." Furthermore, the "view of the object when it is placed on a horizontal surface with the surface on which it is placed facing upwards, from above in the vertical direction in the thickness direction" is referred to as the "planar view."

[0012] Figure 1 is a perspective view of a sheet 10 with scattered protrusions according to this embodiment. Figure 2 is a plan view of a sheet 10 with scattered protrusions according to this embodiment. Figure 3 is a cross-sectional view taken along line AA in Figure 2. As shown in Figure 1, the sheet 10 has a plurality of scattered protrusions 1. As shown in Figure 2, the cross-sectional shape (outer circumference shape) of the protrusions 1 is circular. As shown in Figure 3, the protrusions 1 are single-stage protrusions having a single-stage structure. From the viewpoint of preventing lateral swaying of the object during packaging, the height H1 of the protrusions 1 may be preferably 0.2 or more, more preferably 0.33 or more, and even more preferably 1 or more, in relation to the height of the object (height H1 of the protrusions 1 / height of the object). Also, the height H1 of the protrusions 1 may preferably be 0.1 cm to 5 cm, more preferably 0.2 cm to 4 cm, and even more preferably 0.3 cm to 3 cm. Furthermore, the height H1 of the protrusion 1 may be, more preferably, 0.5 or more, and even more preferably 1 or more, in terms of the ratio of the height H1 of the protrusion 1 to the diameter of the cross-sectional shape of the protrusion 1 (height H1 of the protrusion 1 / diameter of the cross-sectional shape of the protrusion 1).

[0013] Figure 4 is a perspective view of a sheet 40 with scattered protrusions according to this embodiment. In the sheet 40, the height H of the protrusions 41 41 The height of the protrusion 1 of sheet 10 is greater than the height H1 of the protrusion 41. 41 The ratio of the cross-sectional shape of the protrusion to the diameter (protrusion 41 Height H 41 The diameter of the cross-sectional shape of the protrusion 41 is preferably 2 or more, more preferably 3 or more, and even more preferably 5 or more.

[0014] Fig. 5 is a perspective view of a sheet 50 with scattered protrusions according to the present embodiment. Fig. 6 is a plan view of the sheet 50 with scattered protrusions according to the present embodiment. Fig. 7 is a cross-sectional view taken along line A-A in Fig. 6. As shown in Fig. 5, the sheet 50 has a plurality of scattered protrusions 51. As shown in Fig. 6, in the protrusion 51, the cross-sectional shape (outer peripheral shape) of the first-stage and second-stage protrusions is circular. As shown in Fig. 7, the protrusion 51 is a multi-stage protrusion having a two-stage structure consisting of a first stage 51f and a second stage 51s. From the viewpoint of making the protrusions 51 easily crushed when an object is pressed against the protrusions 51, the protrusions are preferably multi-stage protrusions having a multi-stage structure of two or more stages. The protrusions may preferably have two or more stages, more preferably three or more stages, and still more preferably four or more stages. When an object is pressed against such a multi-stage protrusion, the step of the protrusion that abuts against the object is easily crushed, and the shape crushed by the object is maintained. From the viewpoint of preventing rolling of the object during packaging, the height H of the protrusion 51 51 has a ratio to the height of the object (height H of the protrusion 51 51 / height of the object) that is preferably 0.2 or more, more preferably 0.33 or more, and still more preferably 1 or more. Furthermore, the height H of the protrusion 51 51 may preferably be 0.1 cm to 5 cm, more preferably 0.2 cm to 4 cm, and still more preferably 0.3 cm to 3 cm. Furthermore, the height H of the protrusion 51 51 has a ratio to the diameter of the cross-sectional shape of the first stage 51f of the protrusion 51 (height H of the protrusion 51 51 / diameter of the cross-sectional shape of the first stage 51f of the protrusion 51) that is preferably 0.33 or more, more preferably 0.5 or more, and still more preferably 1 or more.

[0015] Furthermore, from the viewpoint of making the protrusion 51 easily crushed when an object is pressed against the protrusion 51, the height H of the first stage 51f of the protrusion 51 51f has a ratio to the height H of the protrusion 51 51 (height H of the first stage of the protrusion 51 51f / H 51 ) that is preferably 0.066 or more, more preferably 0.2 or more, and still more preferably 0.5 or more. Furthermore, the height H of the first stage of the protrusion 51 51fThe height H of the first stage of the protrusion 51 may be preferably 0.1 cm to 1.4 cm, more preferably 0.2 cm to 1.3 cm, and even more preferably 0.3 cm to 1.2 cm. 51f This is the ratio of the cross-sectional shape of the first stage 51f of the protrusion 51 to the diameter (the height of the first stage of the protrusion 51 H 51f The diameter of the cross-sectional shape of the first stage 51f of the protrusion 51 is preferably 0.066 or more, more preferably 0.133 or more, and even more preferably 0.5 or more. Furthermore, when an object is pressed against the protrusion 51, the height H of the second stage 51s of the protrusion 51 is set to make it easier for the protrusion 51 to be crushed. 51s The height H of the protrusion 51 is 51 Ratio to (second stage height H of convex part 51) 51s / H 51 ) may preferably be 0.066 or more, more preferably 0.2 or more, and even more preferably 0.5 or more. Also, the height H of the second stage 51s of the protrusion 51. 51s The height H of the second stage 51s of the protrusion 51 may be preferably 0.1 cm to 1.4 cm, more preferably 0.2 cm to 1.3 cm, and even more preferably 0.3 cm to 1.2 cm. 51s This is the ratio of the cross-sectional shape of the first stage 51f of the protrusion 51 to the diameter (the height H of the second stage of the protrusion 51). 51s The diameter of the cross-sectional shape of the first stage 51f of the protrusion 51 is preferably 0.066 or more, more preferably 0.133 or more, and even more preferably 0.5 or more.

[0016] In this embodiment, when an object is pressed against the protrusion 51 of the sheet and the protrusion 51 is crushed, the protrusion 51 maintains a shape in which the entire protrusion 51 is crushed by the object. Alternatively, when the protrusion 51 is crushed, the protrusion 51 maintains a shape in which a part of the protrusion 51 is crushed by the object. The sheet in this embodiment does not easily return to its original shape after being crushed, and therefore it is possible to sandwich and fix an object in its crushed shape. Figure 8 is a plan view photograph showing the object P being pressed against the protrusion 51 of the sheet and the protrusion 51 being crushed. Figure 9 is an oblique view photograph showing the object P being pressed against the protrusion 51 of the sheet and the protrusion 51 being crushed. Figure 10 is an oblique view photograph showing the state of the protrusion 51 after the object P has been pressed against the protrusion 51 of the sheet and the protrusion 51 has been removed. In Figures 8, 9, and 10, the protrusion 51A retains the shape in which the entire protrusion 51 is crushed. The protrusion 51B retains the shape in which a part of the protrusion 51 is crushed. The protrusion 51C retains its original shape that has not been crushed. As shown in Figures 8, 9, and 10, the object P is fixed by the protrusions 51A, 51B, and 51C. More specifically, as shown in Figure 10, the object P is fixed in place and lateral sway is prevented when it comes into contact with a protrusion 51C adjacent to a protrusion 51A that has been pressed against the object P and has been completely flattened, while the object P retains its original, unflattened shape. Furthermore, these protrusions 51B and 51C provide a cushioning effect against external impacts.

[0017] Figure 11 is a perspective view of the sheet 60 with scattered protrusions according to this embodiment. Figure 12 is a plan view of the sheet 60 with scattered protrusions according to this embodiment. Figure 13 is a cross-sectional view taken along line AA in Figure 12. As shown in Figure 11, the sheet 60 has a plurality of scattered protrusions 61. The cross-sectional shape of the protrusions in this embodiment may be rectangular, such as a square or rectangle, or polygonal, such as a pentagon or hexagon. As shown in Figure 12, the cross-sectional shape (outer circumference) of the protrusions 61 scattered on the sheet 60 is rectangular. As shown in Figure 13, the protrusions 61 are multi-stage protrusions having a three-stage structure: first stage 61f, second stage 61s, and third stage 61t. When an object is pressed against such a multi-stage protrusion, the protrusions of the stages that come into contact with the object are easily crushed, and the shape crushed by the object is maintained. From the viewpoint of preventing lateral movement of the object during packaging, the height H of the protrusions 61 is 61 This is the ratio to the height of the object (height of the protrusion 61 H 61The height of the object is preferably 0.2 or more, more preferably 0.33 or more, and even more preferably 0.5 or more. Also, the height H of the protrusion 61 61 The height H of the protrusion 61 may be preferably 0.1 cm to 5 cm, more preferably 0.2 cm to 0.4 cm, and even more preferably 0.3 cm to 3 cm. 61 The ratio of the cross-sectional shape of the protrusion 61 to the length of the side (height H of the protrusion 61) 61 The side length of the cross-sectional shape of the protrusion 61 is preferably 0.33 or more, more preferably 0.5 or more, and even more preferably 1 or more.

[0018] Also, the height H of the first stage of the protrusion 61 61f The height of the first stage of the protrusion 61 may be preferably 0.1 cm to 1.4 cm, more preferably 0.2 cm to 1.3 cm, and even more preferably 0.3 cm to 1.2 cm. 61f This is the ratio of the side length of the cross-sectional shape of the first stage 61f of the protrusion 61 (the height H of the first stage of the protrusion 61). 61f The side length of the cross-sectional shape of the first stage 61f of the protrusion 61 is preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. Furthermore, when an object is pressed against the protrusion 61, the height H of the second stage 61s of the protrusion 61 is set to make it easier for the protrusion 61 to be crushed. 61s The height H of the protrusion 61 is 61 Ratio to (second stage height H of convex part 61) 61s / H 61 ) may preferably be 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. Also, the height H of the second stage 61s of the protrusion 61. 61s The height H of the second stage of the protrusion 61 may be preferably 0.1 cm to 1.4 cm, more preferably 0.2 cm to 1.3 cm, and even more preferably 0.3 cm to 1.2 cm. 61s This is the ratio of the side length of the cross-sectional shape of the first stage 61f of the protrusion 61 (the height H of the second stage of the protrusion 61). 61sThe side length of the cross-sectional shape of the first stage 61f of the protrusion 61 is preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. Furthermore, when an object is pressed against the protrusion 61, the height H of the third stage 61t of the protrusion 61 is set to make it easier for the protrusion 61 to be crushed. 61t The height H of the protrusion 61 is 61 Ratio to (Third stage height H of protrusion 61) 61t / H 61 ) is preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. Also, the height H of the third stage 61t of the protrusion 61. 61t The height H of the third stage 61t of the protrusion 61 may be preferably 0.1cm to 1.4cm, more preferably 0.2cm to 1.3cm, and even more preferably 0.3cm to 1.2cm. 61t This is the ratio of the side length of the cross-sectional shape of the first stage 61f of the protrusion 61 (height H of the third stage 61t of the protrusion 61). 61t The side length of the cross-sectional shape of the first stage 61f of the protrusion 61 is preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more.

[0019] Next, the sheet according to this embodiment will be described. The sheet according to this embodiment may be a single-layer sheet, or it may be a multilayer sheet with multiple layers such as two or three layers laminated together. Below, the single-layer sheet will be described first, and then the multilayer sheet will be described.

[0020] [Single-layer sheet]

[0021] The single-layer sheet according to this embodiment may be formed from a resin composition. The resin composition may preferably contain a biomass material and a thermoplastic resin. In this embodiment, by including a biomass material, it is possible to obtain a material that is easily crushed when the protrusions scattered on the molded sheet are crushed and that does not easily return to its original shape after being crushed.

[0022] The biomass material is preferably a plant-derived biomass material, and more specifically, starch material and cellulose material. The starch material and cellulose material may be classified as waste biomass, unused biomass, or resource grain. The biomass material may also be of animal origin, for example, biologically derived calcium carbonate such as eggshells and scallop shells.

[0023] As the starch material, raw starch can be used, for example, underground starch and above-ground starch. Underground starch is starch accumulated underground, for example, starch accumulated in rhizomes or roots. Examples of underground starch include, but are not limited to, tapioca starch (cassava starch), potato starch, sweet potato starch, kudzu starch, and bracken starch.

[0024] Ground-based starches are starches accumulated on the ground, such as those accumulated in seeds. Examples of ground-based starches include, but are not limited to, corn starch, wheat starch, sago starch, acorn starch, and rice starch.

[0025] In the single-layer sheet according to this embodiment, above-ground starch is preferably used.

[0026] The starch material may be a modified starch (i.e., modified starch), particularly a modified ground-based starch. Examples of such modified starches include chemically modified starches. Examples of chemically modified starches include acetoacetate esterified starch, acetate esterified starch, hydroxymethyl etherified starch, hydroxypropyl etherified starch, carboxymethyl etherified starch, allyl etherified starch, methyl etherified starch, succinate esterified starch, xanthogene acetate esterified starch, nitrate esterified starch, urea phosphate esterified starch, phosphate esterified starch, phosphate cross-linked starch, formaldehyde cross-linked starch, acrolein cross-linked starch, epichlorohydrin cross-linked starch, and the like.

[0027] Furthermore, when the starch material is corn starch, its particle size is preferably 5 μm or larger, more preferably 10 μm or larger, and even more preferably 15 μm or larger. The upper limit of the particle size is not particularly limited, but is preferably 50 μm or smaller, more preferably 40 μm or smaller, and even more preferably 30 μm or smaller.

[0028] Furthermore, when the starch material is tapioca starch, its particle size is preferably 2 μm or larger, more preferably 10 μm or larger, and even more preferably 15 μm or larger. The upper limit of the particle size is not particularly limited, but is preferably 40 μm or smaller, more preferably 30 μm or smaller, and even more preferably 25 μm or smaller.

[0029] Furthermore, when the starch material is potato starch, its particle size is preferably 2 μm or larger, more preferably 20 μm or larger, and even more preferably 30 μm or larger. The upper limit of the particle size is not particularly limited, but is preferably 80 μm or smaller, more preferably 60 μm or smaller, and even more preferably 40 μm or smaller.

[0030] Furthermore, the starch material may preferably contain equilibrium moisture. The amount of equilibrium moisture may be, for example, preferably 10% to 15% by mass, more preferably 10% to 14% by mass, even more preferably 10% to 13% by mass, and even more preferably 11% to 13% by mass, relative to the mass of the starch material. When compounded with a thermoplastic resin, the moisture content of the starch may preferably be 3% or less.

[0031] Examples of cellulose materials used in this embodiment include paper, paper pulp, cotton, or crushed cloth.

[0032] The particle size D50 (median diameter) of the cellulose material is, for example, 15 μm to 150 μm, and particularly preferably 20 μm to 100 μm. The particle size D50 is determined by wet measurement using a laser diffraction particle size distribution analyzer (SALD-3100, Shimadzu Corporation). By having a particle size within the above numerical range, the cellulose material can contribute to improving the dispersibility of the cellulose material contained in thermoplastic resins.

[0033] Of the cellulose fibers constituting the cellulose material, the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm accounts for 65% to 100%, preferably 70% to 100%, more preferably 80% to 100%, and even more preferably 85% to 100% of the total number of cellulose fibers constituting the cellulose material. The above proportions regarding the number of cellulose fibers are determined by wet measurement using the laser diffraction particle size distribution analyzer to determine the proportion of cellulose fibers having a particle size of 0 μm to 9.8 μm (hereinafter referred to as the "first proportion") and the proportion of cellulose fibers having a particle size of 0 μm to 110.6 μm (hereinafter referred to as the "second proportion") out of the total number of cellulose fibers in the cellulose material, and then subtracting the first proportion from the second proportion. The numerical ranges "0 μm to 9.8 μm" and "0 μm to 110.6 μm" are both numerical ranges input to the laser diffraction particle size distribution analyzer during the wet measurement.

[0034] In this embodiment, particularly preferably, the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm among the cellulose fibers constituting the cellulose material accounts for 0% to 30%, preferably 0% to 25%, more preferably 0% to 20%, and even more preferably 0% to 15% of the total number of cellulose fibers constituting the cellulose material. The above proportions regarding the number of cellulose fibers are determined by wet measurement using the laser diffraction particle size distribution analyzer to determine the proportion of cellulose fibers having a particle size of 0 μm to 110.6 μm (the "second proportion" above) and the proportion of cellulose fibers having a particle size of 0 μm to 998.4 μm (hereinafter referred to as the "third proportion") among the total number of cellulose fibers in the cellulose material, and then subtracting the second proportion from the third proportion. The numerical ranges "0 μm to 110.6 μm" and "0 μm to 998.4 μm" are both numerical ranges input to the laser diffraction particle size distribution analyzer in the wet measurement.

[0035] A cellulose material having the above particle size distribution can be produced, for example, by treating pulp with chemicals such as acids. An example of a cellulose material having the above particle size distribution is KC Floc W400 (Nippon Paper Industries Co., Ltd.). Using cellulose powder having the above particle size distribution results in better moldability when manufacturing sheets.

[0036] In particular, if the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm among the cellulose fibers constituting the cellulose powder accounts for 80% to 100%, and more preferably 85% to 100%, of the total number of cellulose fibers constituting the cellulose powder, then tearing or the occurrence of holes in the sheet obtained by molding the thermoplastic resin can be prevented. In order to prevent tearing or the occurrence of holes in the sheet, it is particularly preferable that the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm among the cellulose fibers constituting the cellulose powder accounts for 0% to 20%, and more preferably 0% to 15%, of the total number of cellulose fibers constituting the cellulose powder.

[0037] In other embodiments, the cellulose powder may have a particle size such that 90% or more of the particles pass through a 100-mesh grid. In this embodiment, it is more preferable that the cellulose powder has a particle size such that 90% or more of the particles pass through a 100-mesh grid, and the apparent specific gravity of the cellulose powder may be 0.30 g / ml to 0.40 g / ml.

[0038] The particle size is measured by the standard sieving method, specifically as follows: 10 g of the sample is placed in a 100-mesh standard sieve, a tray and lid are set on the sieve, and the sample is shaken for 40 minutes using a rotary shaker. The particle size is then calculated from the sample mass (10 g) and the mass of the sieved residue using the following formula. Particle size (%) = [(Sample mass (g) - Sieve residue (g)) / Sample mass (g)] × 100

[0039] The apparent specific gravity is measured as follows: 10 g of the sample is accurately weighed on a balance and placed in a 50 ml graduated cylinder. The bottom of the graduated cylinder is tapped on a rubber-covered surface, taking care not to let the sample spill. This tapping is continued until no more sample can clog the cylinder. After tapping, the surface of the sample is flattened, and the scale (volume, ml) is read. The apparent specific gravity is then calculated using the following formula. Apparent specific gravity (g / ml) = Sample (10g) / Volume (ml)

[0040] Cellulose powder having the above particle size (or the above particle size and apparent specific gravity) can be produced, for example, by mechanically grinding pulp (e.g., by jet mill grinding). An example of cellulose powder having the above particle size (or the above particle size and apparent specific gravity) is KC Floc 100GK.

[0041] In this embodiment, from the viewpoint of obtaining ease of crushing of the convex portions scattered on the formed sheet and resistance to returning to their original shape after crushing, the biomass material content is preferably 4% to 95% by mass, more preferably 6% to 93% by mass, and even more preferably 8% to 90% by mass, relative to the mass of the resin composition.

[0042] The thermoplastic resin used in the single-layer sheet according to this embodiment may be a polyolefin resin, a polyester resin, or a mixture of these resins. Alternatively, the thermoplastic resin may be a polystyrene resin. Furthermore, the thermoplastic resin may contain biodegradable materials to avoid reducing its biodegradability.

[0043] Polyolefin resins are polymers obtained by polymerization using olefins (e.g., α-olefins) as the main monomers. Polyolefin resins may be, for example, polyethylene (PE) resin or polypropylene (PP) resin, or a combination thereof. Furthermore, polyolefin resins may be homopolymers, block copolymers, or random copolymers.

[0044] The polyethylene resin may be, for example, low-density polyethylene (LDPE), high-density polyethylene (HDPE), very low-density polyethylene (VLDPE), linear low-density polyethylene (LLDPE), ethylene copolymers such as ethylene-vinyl acetate copolymer (EVA resin), or ultra-high molecular weight polyethylene (UHMW-PE), or a combination thereof.

[0045] The polyolefin resin may preferably be a biomass-derived polyolefin resin (for example, a biomass-derived polyethylene resin), and may be, for example, a biomass polyethylene resin. The biomass polyethylene resin may be, for example, LDPE, LLDPE, or HDPE. This can reduce CO2 emissions.

[0046] The polyolefin resin may be a polyolefin resin produced using a metallocene catalyst. That is, the thermoplastic resin may be, for example, a metallocene catalyst-based polyethylene resin or polypropylene resin, or a combination thereof. The polystyrene resin may be a metallocene catalyst-based polystyrene resin.

[0047] Polyester resins are polymers formed by the polymerization of monomers via ester bonds. Examples of polyester resins include polyethylene terephthalate resin (PET), polyethylene naphthalate resin (PEN), polybutylene terephthalate resin (PBT), polylactic acid resin (PLA), or polycarbonate resin (PC), polybutylene adipate terephthalate resin (PBAT), polybutylene succinate resin (PBS), polyhydroxyalkanoate resin (PHA), or combinations of two or more of these.

[0048] Polystyrene resins are polymers formed by the polymerization of styrene monomers. Polystyrene resins may include, for example, polystyrene resin, rubber-reinforced polystyrene resin (high-impact polystyrene resin, HIPS), acrylonitrile-styrene copolymer (AS resin), methacrylic acid ester-styrene copolymer, acrylonitrile-acrylic rubber-styrene copolymer, and acrylonitrile-ethylene propylene-styrene copolymer, or combinations of two or more of these.

[0049] In this embodiment, the type of thermoplastic resin may be appropriately selected by those skilled in the art, for example, depending on the packaging application, and a thermoplastic resin with a low processing temperature is preferred. For example, in the case of a sheet used for food packaging, the thermoplastic resin may be, for example, preferably a polyolefin resin, more preferably a polyethylene resin or a polypropylene resin, and even more preferably a polypropylene resin.

[0050] In this embodiment, the melting point of the thermoplastic resin is preferably 170°C or lower, and more preferably 165°C or lower. By using a thermoplastic resin with a lower melting point, the temperature during sheet molding can be reduced. Furthermore, the melting point of the thermoplastic resin is preferably 90°C or higher, and more preferably 95°C or higher.

[0051] As the thermoplastic resin, pelletized granular material may be used. The content of the thermoplastic resin is preferably 3% to 95% by mass, more preferably 5% to 93% by mass, and even more preferably 8% to 90% by mass, based on the mass of the resin composition.

[0052] Examples of the biodegradable materials include cellulose derivatives such as methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, and hydroxybutylmethylcellulose; hydrophilic polymer materials such as polyvinyl alcohol, carboxymethylcellulose, polyacrylic acid polymers, and polyacrylamide; emulsions such as various acrylates, ethylene / vinyl acetate copolymers, and polyurethanes; and aliphatic polyester resins such as caprolactone, polylactic acid, polybutylene adipate, polybutylene succinate, and polyhydroxybutyrate / variate copolymers.

[0053] The single-layer sheet according to this embodiment may further contain additives in addition to the biomass material and the thermoplastic resin. Such additives may include low-melting-point additives that have a melting point lower than the melting temperature of the thermoplastic resin and melt at a relatively low temperature. Preferably, such low-melting-point additives melt at 100°C or below, and more preferably at 60-100°C. As such low-melting-point additives, ester compounds that are liquid or solid at room temperature are preferably used. Specifically, examples of low-melting-point additives include monoglycerides, diglycerides, triglycerides, acetylated monoglycerides, organic acid monoglycerides, medium-chain fatty acid monoglycerides, polyglycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, special fatty acid esters, and higher alcohol fatty acid esters. Glycerin-based fatty acid esters are preferably used. Low-melting-point additives melt at a relatively low temperature, possess viscosity, and can function to entangle and adhere to the biomass material powder.

[0054] The low-melting-point additive may be blended in a proportion of, for example, preferably 0.1 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of biomass material.

[0055] Furthermore, the low-melting-point additive may be included in the resin composition in a content ratio of, for example, preferably 0.1% to 5% by mass, and more preferably 0.1% to 3% by mass, relative to the mass of the resin composition.

[0056] Furthermore, the resin composition may contain a high-melting-point additive having a higher melting point than the low-melting-point additive. Such a high-melting-point additive may have a higher melting point than the low-melting-point additive, preferably in the range of 100 to 150°C, solidify before the low-melting-point additive, and have a melting point lower than the melting temperature of the thermoplastic resin. Examples of such high-melting-point additives include fatty acid metal salts, hydrocarbons, higher alcohols, aliphatic amides, and fatty acid esters. Specifically, magnesium stearate, zinc stearate, calcium stearate, aluminum stearate, sodium lauryl sulfate, magnesium lauryl sulfate, potassium benzoate, sodium benzoate, and sodium stearyl fumarate are used.

[0057] The high-melting-point additive may be included in the resin composition in a content ratio of, for example, preferably 0.1% to 10% by mass, and more preferably 0.1% to 5% by mass, relative to the mass of the resin composition.

[0058] Other additives that can be used include compatibilizers to improve the affinity between biomass materials and thermoplastic resins. The compatibilizer may be selected depending on the type of thermoplastic resin. Examples of such compatibilizers include acid-modified polyolefins, acid-modified nylons, acid-modified polystyrenes, acid-modified EVAs, acid-modified ethylene copolymers, acid-modified acrylates, acrylic acid-modified EVAs, and modified ethylene acrylates.

[0059] When the thermoplastic resin is a polyolefin-based resin, the compatibilizer is preferably an acid-modified polyolefin, and in particular may be a carboxylic acid anhydride-modified polyolefin or an olefin-based comonomer.

[0060] The carboxylic acid anhydride constituting the carboxylic acid anhydride-modified polyolefin is preferably maleic anhydride. The compatibilizer is, for example, a maleic anhydride-grafted polyolefin resin, and more particularly, one or more combinations selected from the group consisting of maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, and maleic anhydride-modified ethylene-propylene copolymer. A rubber component may be dispersed in the compatibilizer.

[0061] The compatibilizer may be included in the resin composition in a content ratio of, for example, 0.1% to 10% by mass, more preferably 1.0% to 5.0% by mass, relative to the mass of the resin composition.

[0062] Other additives that can be used include colorants.

[0063] Colorants can be used to color resin compositions. Examples of colorants include titanium dioxide, carbon black, dyes, and pigments.

[0064] Inorganic fillers can be used as other additives. Examples of inorganic fillers include inorganic powders. Preferably, shell powders, mineral powders, etc., are used as inorganic powders. The specific gravity of the inorganic powder used is preferably 2.5 g / cm³. 3 More preferably 2.55 g / cm³ 3 More preferably 2.6 g / cm³ 3 More preferably 2.65 g / cm³ 3 That's all.

[0065] Shell powder refers to a powder made by crushing shells. The shells used are not particularly limited, and can include shells of scallops, oysters, surf clams, abalone, mussels, clams, and cockles. Shell powder may be obtained, for example, by washing and sterilizing shells discarded from food factories and then crushing them, or it may be obtained from shells of shellfish not used for food purposes. The method of crushing the shells is not particularly limited, and any known crushing method may be appropriately selected and adopted, and it may be either wet or dry. Alternatively, the shells may be pre-crushed in a coarse crusher and then powdered in a pulverizer. Specifically, coarse crushers include jaw crushers, cone crushers, cutter mills, and hammer crushers, and pulverizers include roll mills, stamp mills, hammer mills, ball mills, vibrating ball mills, roller mills, and vertical mills. Preferably, the shell powder is scallop shell powder. Examples of scallop shell powder include uncalcined scallop shell powder and calcined scallop shell powder. Uncalcined scallop shell powder is made by grinding natural scallop shells into a powder and keeping them in an uncalcined state. Its main component (approximately 96%) is usually calcium carbonate. Uncalcined scallop shell powder is available commercially.

[0066] Examples of mineral powders include clay mineral powder. Such clay mineral powders can be either natural or synthetic. Examples of clay mineral powders include calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, potassium titanate, bentonite, wollastonite, dolomite, and graphite. Among these, talc powder is particularly preferred. As for inorganic powders, only seashell powder may be used, only mineral powder may be used, or a mixture of seashell powder and mineral powder may be used.

[0067] Furthermore, other components such as antioxidants, crosslinking agents, UV absorbers, foaming agents, and impact absorbing agents may be used. Commercially available additives may be used for these purposes.

[0068] [Multilayer sheet]

[0069] Next, a multilayer sheet according to this embodiment will be described with reference to the drawings. Figure 14 shows a two-layer sheet composed of layer A and layer B according to this embodiment. As shown in Figure 14, in the two-layer multilayer sheet, layer A is formed from a resin composition containing a polyolefin resin. The polyolefin resin has been described in the single-layer sheet above, so its explanation will be omitted. In layer A, the polyolefin resin contained in the resin composition may be preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and may be 100% by mass, based on the mass of the resin composition. Layer B is formed from a resin composition containing a biomass material and a thermoplastic resin, etc., as described in the single-layer sheet above. The resin composition has also been described above, so its explanation will be omitted. In the two-layer multilayer sheet, either layer A or layer B may be on the convex surface side.

[0070] Furthermore, the multilayer sheet according to this embodiment may also be a three-layer sheet. Figure 15 shows a three-layer sheet according to this embodiment, consisting of layer A, layer B, and layer A. As shown in Figure 15, it has a structure in which layer B is used as an intermediate layer, and layer A is laminated on both sides of the intermediate layer as an outer layer. Figure 16 shows a three-layer sheet according to this embodiment, consisting of layer A, layer B, and layer C. As shown in Figure 16, it has a structure in which layer B is used as an intermediate layer, and layer A and layer C are laminated on both sides of the intermediate layer as outer layers. Layers A and B are as described in the single-layer sheet above, so their description is omitted. Layer C is a compound layer formed from a polyolefin resin. In the three-layer multilayer sheet, either layer A or layer C may be on the convex surface side.

[0071] (2) Method for manufacturing sheets

[0072] [Manufacturing method for single-layer sheets]

[0073] The method for manufacturing a single-layer sheet according to this embodiment may include: a biomass material drying step in which biomass material is placed in a container equipped with a heating element on the outside, and the biomass material is dried while the inside of the container is heated by the heating element, thereby preventing the biomass material from adhering to the inner surface of the container; a resin composition preparation step in which the biomass material dried in the biomass material drying step is mixed with a thermoplastic resin to prepare a resin composition; and a molding step in which the resin composition prepared in the resin composition preparation step is molded to obtain a sheet with scattered protrusions.

[0074] The method for manufacturing a single-layer sheet according to this embodiment may include a biomass material drying step (S1), a resin composition preparation step (S2), and a molding step (S3). Each step will be described below.

[0075] <Biomass material drying process (S1)>

[0076] In the biomass material drying process (S1), the biomass material is placed inside a container. The container in which the biomass material is placed is equipped with an external heating element that heats the inside of the container. Examples of such containers include a heating agitator having a heating jacket around a cylindrical container made of stainless steel or steel. In such a heating agitator, the outer circumference of the containment section in which the biomass material is placed is covered with a heating jacket. Agitation blades are provided inside the containment section. The heating jacket is filled with a heat transfer medium such as oil, hot water, or heated steam, and the heating jacket can function as a heating element. The heating jacket heats the containment section inside the container by heating the inner surfaces such as the inner walls, lid, and bottom surfaces of the container. The heating jacket heats the inner surfaces inside the container so that there are no areas that are not sufficiently heated. By ensuring that there are no areas that are not sufficiently heated inside the container, condensation of moisture in the biomass material evaporated by heating is suppressed from coming into contact with areas that are not sufficiently heated. By suppressing condensation on the inner surface of the heating agitator, the biomass material contained in the container, which prevents starch and other biomass materials from gelatinizing and adhering to the inner surface of the heating agitator, is dried within the heated container. Furthermore, during the drying of the biomass material, gelatinization of starch and other biomass materials can be prevented and drying efficiency can be improved by continuously moving the biomass material using stirring blades. The shape of the stirring blades 12 can be selected from any shape such as propeller blades, paddle blades, inclined paddle blades, turbine blades, screw blades, anchor blades, ribbon blades, and large grid blades. Such a heating agitator is also called an external heating jacket type mixer.

[0077] In this process, from the viewpoint of efficiently drying the biomass material, the temperature inside the container is preferably 120°C or higher, more preferably 135°C or higher, and even more preferably 150°C or higher. Furthermore, from the viewpoint of suppressing thermal degradation of the biomass material, the temperature inside the container is preferably 200°C or lower, more preferably 190°C or lower, and even more preferably 180°C or lower.

[0078] The stirring may be performed by setting the rotation speed of the stirring blade to preferably 500 to 2000 rpm, more preferably 750 to 1750 rpm, and even more preferably 1000 to 1500 rpm.

[0079] In this process, the drying time for the biomass material is not limited, but can be set appropriately depending on the amount of biomass material from the viewpoint of drying efficiency. For example, it may be preferably 10 to 30 minutes, more preferably 15 to 30 minutes, and even more preferably 15 to 25 minutes.

[0080] In this process, the biomass material is prevented from adhering to the inner surface of the container where it is contained. When the biomass material is heated inside the container, the water contained in the biomass material evaporates. The evaporated water comes into contact with areas on the inner surface of the container, such as the inner wall surface, the inner surface of the lid, and the bottom surface, where the temperature rise due to heating is insufficient, causing condensation. When the biomass material contained inside the container adheres to the inner surface of the container where condensation has occurred, the biomass material is heated in the presence of water. For example, if the biomass material is starch, under heating, water enters the molecular chains of the starch, loosening the molecular structure and causing swelling (alpha-gelatinization), resulting in granular material known as "white grains." In the infrared absorption spectrum, "white grains" have an absorption peak derived from starch. Such an absorption peak is a peak derived from OH bonds, and the peak is located in the range of 3000 to 3500 cm-1. Also, "white grains" do not color when stained with iodine. Typically, starch particles have a major axis of 10-20 μm, while granular material referred to as "white grains" has a major axis of 100-200 μm, which is larger than ungelatinized starch particles. Unungelatinized starch refers to starch that has not gelatinized before heating or even after heat drying treatment. Such "white grains" can cause mesh clogging and inclusion of white grains in the sheet during sheet or film extrusion molding, leading to brown discoloration, and can also cause holes in the resulting molded product during molding. In this process, the inside of the container is heated by an externally provided heating element, ensuring that there are no areas on the inner surface of the container where the temperature rise is insufficient. This suppresses condensation and prevents the biomass material inside the container from adhering to the inner surface. By preventing the biomass material from adhering to the inner surface of the container in this way, the generation of white grains can be suppressed, making it possible to efficiently manufacture molded products with superior quality. Furthermore, stirring the biomass material inside the container to prevent it from accumulating in one place is also preferable to suppress the biomass material from adhering to the inner surface of the container.

[0081] The above describes the use of an externally heated jacketed mixer, but in the biomass material drying process (S1) in this embodiment, a heated jacketed vacuum dryer may also be used. This dryer preferably has an external heating jacket and stirring blades inside the container, and the biomass material can be dried by creating a vacuum inside the container.

[0082] When using a heated jacket type vacuum dryer, from the viewpoint of efficiently drying the biomass material, the temperature inside the container is preferably 100°C or higher, more preferably 115°C or higher, and even more preferably 130°C or higher. Furthermore, from the viewpoint of suppressing thermal degradation of the biomass material, the temperature inside the container is preferably 200°C or lower, more preferably 185°C or lower, and even more preferably 170°C or lower.

[0083] The vacuum level inside the container is preferably set to 5kPa to 30kPa, more preferably to 5kPa to 25kPa, and even more preferably to 5kPa to 20kPa.

[0084] In this process, the drying time for the biomass material is not limited, but can be appropriately set depending on the amount of biomass material from the viewpoint of drying efficiency. For example, it is preferably 30 to 90 minutes, more preferably 40 to 80 minutes, and even more preferably 50 to 70 minutes. In this process, the biomass material may be dried to a moisture content of preferably 5% or less, more preferably 2% or less.

[0085] <Resin composition preparation process (S2)>

[0086] In the resin composition preparation step (S2), the biomass material dried in the drying step (S1) and the thermoplastic resin are mixed in an extruder to prepare the resin composition. In this process, when mixing the dried biomass material and the thermoplastic resin, for example, the dried biomass material and the thermoplastic resin may be simply mixed in a dry state to prepare a resin composition which is a mixture of powdered biomass material and pelletized thermoplastic resin. Alternatively, the dried biomass material and thermoplastic resin may be simultaneously fed into an extruder via a feeder, and the biomass material and thermoplastic resin may be uniformly kneaded and mixed by heating and kneading while controlling the rotation speed, stirring time, and temperature, thereby obtaining the resin composition from the molten and kneaded mixture of biomass material and thermoplastic resin present in the extruder. Furthermore, the molten and kneaded mixture of biomass material and thermoplastic resin may be extruded from the extruder, cooled, and pelletized to obtain the resin composition. A single-screw extruder or a twin-screw extruder can be used as such an extruder. In addition, when feeding the biomass material and thermoplastic resin into the extruder, additives may be added at the same time, such as low-melting-point additives and high-melting-point additives. Alternatively, the biomass material, thermoplastic resin, and additives may each be fed individually via feeders in predetermined proportions.

[0087] When mixing the biomass material and the thermoplastic resin in an extruder, the heating temperature (cylinder temperature) may be set to a temperature below the melting point of the thermoplastic resin, or above the melting point of the high-melting-point additive, from the viewpoint of suppressing material deterioration and discoloration. For example, the heating temperature (cylinder temperature) may be set to 100 to 190°C.

[0088] <Molding process (S3)>

[0089] In this process, the resin composition prepared in the resin composition preparation step (S2) is molded to obtain a sheet. For example, in the resin composition preparation step (S2), biomass material and thermoplastic resin are sufficiently heated and mixed in an extruder to prepare a resin composition. The resin composition is then transferred to a molding machine, and the resin composition is molded using the molding machine to form a sheet. The temperature used for molding the sheet may preferably be set to a temperature above the melting temperature of the thermoplastic resin, for example, 150 to 450°C, and the molding pressure may be set appropriately. The formed sheet is further molded using a vacuum molding machine to obtain a sheet with scattered protrusions. Examples of such vacuum molding machines include the WAKITEC FVS-500P (Wakisaka Engineering Co., Ltd.). The shape of the mold used in the vacuum molding machine can be matched to the shape of the protrusions to be formed on the sheet to create protrusions of the required shape on the sheet surface. Alternatively, the protrusions may be created simultaneously with the sheet molding.

[0090] <Biomass material cooling process (S4)>

[0091] In the method for manufacturing a single-layer sheet according to this embodiment, a biomass material cooling step (S4) may be provided between the biomass material drying step (S1) and the resin composition preparation step (S2). This step can be carried out, for example, using a manufacturing apparatus having a heating stirrer, a cooling stirrer, and an extruder.

[0092] The biomass material and thermoplastic resin are heated and stirred in a heating agitator. Alternatively, the biomass material, thermoplastic resin, and low-melting-point additive may be heated and stirred in the heating agitator. After that, the mixture of biomass material and thermoplastic resin may be transferred to a cooling agitator and cooled while being stirred in the cooling agitator to a temperature above the melting temperature of the low-melting-point additive, and close to its melting temperature. Alternatively, the mixture of biomass material and thermoplastic resin may be cooled without stirring.

[0093] [Manufacturing method for multilayer sheets]

[0094] The multilayer sheet according to this embodiment may include a biomass material drying step in which biomass material is contained in a container equipped with an external heating element, and the biomass material is dried by stirring while the inside of the container is heated by the heating element; a resin composition preparation step in which the biomass material dried in the biomass material drying step is mixed with a thermoplastic resin to prepare a resin composition; and a multilayer extrusion molding step in which the resin composition prepared in the resin composition preparation step and a resin composition of a different type from the resin composition are multilayer extruded to obtain a laminate in which different types of resin layers are laminated together.

[0095] The method for manufacturing a multilayer sheet according to this embodiment may include a biomass material drying step (S1), a resin composition preparation step (S2), and a multilayer extrusion molding step (S6). It may also include a biomass material cooling step (S4). Note that the biomass material drying step (S1), the resin composition preparation step (S2), and the biomass material cooling step (S4) are the same steps as in the method for manufacturing a single-layer sheet, so their explanation will be omitted. The multilayer extrusion molding step (S6) will be described below.

[0096] <Multilayer extrusion process (S6)>

[0097] In the multilayer extrusion molding process (S6), a resin composition of a different type from the resin composition is extruded and molded so that different types of resin layers are stacked on top of each other to obtain a laminate. The laminate can be obtained, for example, using a multilayer co-extrusion molding machine. The multilayer co-extrusion molding machine may have an extruder for layer A, an extruder for layer B, an extruder for layer C, a feed block, and dies. Using the multilayer co-extrusion molding machine, a three-layer structure sheet is co-extruded in which layers A, B, and C are stacked, with layer B containing biomass material as the middle layer and layers A and C as the surface layers. The extruder for layer B extrudes the resin composition prepared in the resin composition preparation process (S2), and the extruder for layer A and the extruder for layer C each extrude a thermoplastic resin composition of a different type from the resin composition extruded from the extruder for layer B. When manufacturing a two-layer sheet consisting of layer A and layer B, for example, the sheet is formed using the extruder for layer A and the extruder for layer B. Furthermore, when manufacturing a three-layer sheet in which layer B is the intermediate layer and layer A is the outer layer, for example, an extruder for layer A, an extruder for layer B, and an extruder for layer C are used, and the resin composition used for the extruder for layer B is supplied to the extruder for layer C to form the three-layer sheet. The same method as for a single-layer sheet may be used to scatter protrusions on the sheet, and the protrusions can be formed simultaneously on layers A, B, and C.

[0098] (3)Applications

[0099] The sheet according to this embodiment can secure the object being transported within the packaging container during transportation, preventing lateral swaying due to vibrations, etc. Furthermore, regardless of the shape of the object, when packing it into the container, pressing the object against the protrusions of the sheet crushes all or part of the protrusions, and the object can be held in place by the fully crushed protrusions, partially crushed protrusions, and protrusions that maintain their original shape. In other words, there is no need to prepare cushioning material in advance according to the shape of the object being transported. Figure 17 is a perspective view showing the object P pressed against the sheet 60. Figure 18 is a cross-sectional view taken along line AA in Figure 17. As shown in Figures 17 and 18, the object P pressed against the sheet 60 is fitted into and secured by the completely crushed protrusions 61A, partially crushed protrusions 61B, and protrusions 61 that maintain their original shape, thereby suppressing lateral swaying due to vibrations, etc. during transportation.

[0100] The sheet according to this embodiment can be restored to the shape of the convex portion before it was crushed by applying an external force from the back of the crushed convex portion. This will be explained using photographs. Figure 19 is a photograph taken from the back of the surface of the sheet 50 that contacts the object, showing the convex portion 51A that has been completely crushed by pressing an object against it. Figure 20 is a photograph taken from the back of the convex portion 51A after the crushed portion has been pressed with a finger from the back to restore its shape. Figure 21 is a photograph taken of the convex portion 51A after its shape has been restored by a finger.

[0101] In this embodiment, when the sheet returns to the shape of the convex portion before being crushed, it presses the object against the convex portion. When the convex portion is crushed, the convex portion maintains a shape in which the entire convex portion is crushed or a shape in which a part of the convex portion is crushed by the object. The object is fixed in place by the crushed convex portion and / or the convex portion that maintains its original, uncrushed shape. In other words, the sheet in this embodiment has the function of preventing the object from swaying even after multiple uses. This embodiment also provides packaging materials including the sheet. For example, by using a packaging box and the sheet as packaging materials, goods or products can be fixed in place and swayed during transportation.

[0102] This technology can also employ the following configuration: [1] A sheet with scattered protrusions, A sheet in which, when an object is pressed against the protrusion and the protrusion is crushed, the protrusion maintains a shape in which the entire protrusion is crushed or a shape in which a part of the protrusion is crushed by the object, and the object is fixed by the crushed shape of the protrusion and / or the protrusion that maintains its original, uncrushed shape. [2] The sheet according to [1], wherein the sheet is formed from a resin composition containing a biomass material and a thermoplastic resin. [3] The sheet according to [1] or [2], wherein the cross-sectional shape of the convex portion is circular. [4] The sheet according to any one of [1] to [3], wherein the cross-sectional shape of the convex portion is rectangular. [5] The sheet according to any one of [1] to [4], wherein the cross-sectional shape of the convex portion is polygonal. [6] The sheet according to any one of [1] to [5], wherein the aforementioned protrusion is a single-stage protrusion. [7] The sheet according to any one of [1] to [6], wherein the aforementioned protrusion is a multi-stage protrusion. [8] The sheet according to [7], wherein when the object is pressed against the multi-stage protrusions, the protrusions of the stages that come into contact with the object are easily crushed and the sheet retains the shape crushed by the object. [9] A sheet according to any one of [1] to [8], which returns to the shape of the convex portion before it was crushed by applying an external force from the back side of the crushed convex portion.

[10] The sheet according to [9], wherein when the protrusion returns to its shape before being crushed, an object is pressed against the protrusion, and when the protrusion is crushed, the protrusion maintains a shape in which the entire protrusion is crushed or a shape in which a part of the protrusion is crushed by the object, and the object is fixed by the crushed shape of the protrusion and / or the protrusion that maintains its original, uncrushed shape.

[11] Packaging materials including any of the sheets described in [1] through

[10] .

[0103] 2. Examples

[0104] The present technology will be described in more detail below based on the examples. Note that the examples described below are representative examples of the present technology, and the scope of the present technology is not limited to these examples. The evaluation methods and evaluation criteria used in the examples are as follows.

[0105] (Example 1)

[0106] In a heated agitator (external heated jacket type mixer, Kawata Co., Ltd.), 56.31 parts by mass of corn starch (manufactured by Showa Sangyo Co., Ltd.) with an initial moisture content of 14% and 1.08 parts by mass of glycerin fatty acid ester were mixed with a total of 100 parts by mass of each component (ratio of corn starch before drying), and the mixture was dried for 20 minutes at a heated jacket temperature of 150°C. The moisture content of the corn starch after drying was 2%. Corn starch, 29.57 parts by mass of polypropylene (product name: CS356M, manufactured by Sun Allomer Co., Ltd.), 1.07 parts by mass of zinc stearate, 3.27 parts by mass of magnesium stearate, 3 parts by mass of styrene-based thermoplastic elastomer (product name: Septon® 4033, manufactured by Kuraray Co., Ltd.), acid-modified polyethylene (product name: Fusabond® N493, manufactured by DuPont), and 2.7 parts by mass of white pigment were compounded using a twin-screw extruder (Ikegai Co., Ltd. PCM30, screw diameter: 30φ) to obtain pellets. The obtained pellets were supplied via a hopper to the B-layer extruder of a multi-layer co-extrusion molding machine (manufactured by LAB TECH Engineering Co., Ltd.).

[0107] Furthermore, a polypropylene resin composition (product name: EG6D, manufactured by Nippon Polypropylene Co., Ltd.) was supplied to the A-layer extruder of a multilayer co-extrusion molding machine (manufactured by LAB TECH Engineering Co., Ltd.) via a hopper, and the same polypropylene resin composition (product name: EG6D, manufactured by Nippon Polypropylene Co., Ltd.) was supplied to the C-layer extruder via a hopper. The resin compositions supplied to the A-layer extruder, B-layer extruder, and C-layer extruder were co-extruded to obtain a multilayer sheet with a three-layer structure, with the B-layer as the middle layer. The thickness of the obtained multilayer sheet was 0.5 mm.

[0108] The cylinder temperature and adapter temperature of the extruder for layer A (model number: LE25-30 / C (manufactured by LAB TECH Engineering Co., Ltd.), L / D: 30, φ: 250 mm), the extruder for layer B (model number: LE25-30 / C (manufactured by LAB TECH Engineering Co., Ltd.), L / D: 30, φ: 250 mm), and the extruder for layer C (model number: LE25-30 / C (manufactured by LAB TECH Engineering Co., Ltd.), L / D: 30, φ: 250 mm) were set to 200°C. In addition, the screw speed of the extruder for layer B was set to 90 RPM, and the screw speeds of the extruders for layer A and layer C were set to 20 RPM.

[0109] The resulting multilayer sheet is processed using a vacuum forming machine (WAKITEC Using FVS-500P (Wakisaka Engineering Co., Ltd.), a sheet 50 was formed with circular protrusions scattered on the surface of layer A. Figure 22 is a perspective view of the obtained sheet 50. A rectangular metal P was pressed onto the obtained sheet 50 to crush the protrusions 51 scattered on the surface of the sheet 50. Figure 23 is a photograph showing the sheet 50 after the rectangular metal P was pressed onto it and the protrusions 51 scattered on the surface of the sheet 50 were crushed. As shown in Figure 23, the rectangular metal P is surrounded by a completely crushed protrusion 51A, a partially crushed protrusion 51B, and a protrusion 51C that maintains its original shape. Figure 24 is a magnified section showing the relationship between the rectangular metal P and the protrusions. As shown in Figure 24, the rectangular metal P is sandwiched and fixed between the completely crushed protrusion 51A (hidden by the metal P), the partially crushed protrusion 51B, and the protrusion 51C that maintains its original shape.

[0110] Furthermore, a wrench S was pressed against the obtained sheet 50 to crush the protrusions 51 scattered on the surface of the sheet 50. Figure 25 is a photograph showing the result of pressing the wrench S against the sheet 50 and crushing the protrusions 51 scattered on the surface of the sheet 50. As shown in Figure 25, the wrench S is surrounded by a completely crushed protrusion 51A, a partially crushed protrusion 51B, and a protrusion 51C that maintains its original shape. Figure 26 is a magnified photograph showing the relationship between the wrench S and the protrusions. As shown in Figure 26, the wrench S is sandwiched and fixed between the completely crushed protrusion 51A, the partially crushed protrusion 51B, and the protrusion 51C that maintains its original shape. In this way, the sheet according to this embodiment can also fix objects with complex shapes.

[0111] [Vibration Test]

[0112] A 350g metal sample (10cm long x 9.2cm wide x 1.5cm thick) was pressed onto the obtained sheet 50 by hand, and the protrusions were crushed to fix the metal sample in place. Sheet 50 was moved back and forth 20 times in 10 seconds, alternating between 3cm to the left and 3cm to the right. It was checked whether the position of the metal sample changed from the starting position of the test. After the test was completed, it was confirmed that the position of the metal sample was the same as before the test.

[0113] (Reference example 1)

[0114] A sheet with scattered protrusions was formed using a single-layer polypropylene sheet with a thickness of 0.4 mm (manufactured by I-Sheet Industry Co., Ltd.) in the same manner as in Example 1. A 350 g metal sample (10 cm long x 9.2 cm wide x 1.5 cm thick) was pressed onto the resulting sheet by hand in an attempt to fix the metal sample by crushing the protrusions, but it was not possible to crush the protrusions.

[0115] The configurations, methods, processes, shapes, materials, and numerical values ​​mentioned in the above embodiments and examples are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values ​​may be used as needed.

[0116] Furthermore, the configurations, methods, processes, shapes, materials, and numerical values ​​of the above-described embodiments and examples can be combined with each other, as long as they do not depart from the spirit of these embodiments.

[0117] Furthermore, in this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step may be replaced with the upper or lower limit of a numerical range in another step. Unless otherwise specified, the materials exemplified in this specification may be used individually or in combination of two or more. [Explanation of symbols]

[0118] 1. Convex part 10 sheets 40 sheets 41 Convex part 50 sheets 51 Convex part 51f First stage of the convex section 51s Second stage of the convex part 60 sheets 61 Convex part 61f First stage of the convex section 61s Second stage of the convex part 61t Third stage of the convex section

Claims

1. A sheet with scattered protrusions, The cross-sectional shape of the convex portion is rectangular or polygonal. The aforementioned protrusion is a multi-stage protrusion, The aforementioned sheet is formed from a resin composition containing a starch material and a thermoplastic resin. When an object is pressed against the protrusion and the protrusion is crushed, the protrusion maintains a shape in which the entire protrusion is crushed or a shape in which a part of the protrusion is crushed by the object, and the object is fixed in place by the crushed shape of the protrusion and / or the protrusion that maintains its original, uncrushed shape. The crushed protrusion is difficult to return to its original shape, and the object is clamped and fixed by the shape of the crushed protrusion. A sheet is used to fix a metal sample weighing 350 g (10 cm long x 9.2 cm wide x 1.5 cm thick) by pressing it down by hand, crushing the protrusions to secure the metal sample, and then the sheet is moved back and forth 20 times in 10 seconds, alternating between 3 cm to the left and 3 cm to the right, until the position of the metal sample is the same as before the movement.

2. The sheet according to claim 1, wherein when the object is pressed against the multi-stage protrusions, the protrusions of the stages that come into contact with the object are easily crushed and maintain the shape crushed by the object.

3. The sheet according to claim 1, wherein applying an external force from the back side of the crushed protrusion returns the protrusion to its original shape before being crushed.

4. When the protrusion returns to its shape before being crushed, the object is pressed against the protrusion, and when the protrusion is crushed, the protrusion maintains a shape in which the entire protrusion is crushed or a shape in which a part of the protrusion is crushed by the object, and the object is fixed in place by the crushed shape of the protrusion and / or the protrusion that maintains its original, uncrushed shape. The sheet according to claim 3, wherein the crushed protrusions are difficult to return to their original shape, and the sheet clamps and fixes the object with the shape of the crushed protrusions.

5. Packaging material comprising the sheet described in claim 1.

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