Sheet

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

Sheet

[0001] The present technology relates to a seat.

[0002] To facilitate transport of goods and products and to prevent damage during transport, cushioning material is inserted into the gap between the goods and products and the container. Conventional cushioning materials used for packaging include synthetic resin bubble wrap, air cushions, loose cushioning, kraft paper, mirror mats, paper cushions, and stretch films, which have multiple air-filled hollow spaces. Synthetic resin bubble wrap can be difficult to handle due to its bulky hollow spaces, even during storage or disposal. Furthermore, air cushions, loose cushioning, kraft paper, mirror mats, paper cushions, and stretch films inevitably result in a large amount of waste material, requiring time and effort for purchasing the materials and securing storage space. To reduce waste material, a cardboard packaging container has been proposed that includes a holding member that holds the goods and products in place inside the container (Patent Document 1).

[0003] Utility Model Registration No. 3160273

[0004] However, the technology of Patent Document 1 requires the preparation of a holding member that matches the size and shape of the product, and because the holding member is made of cardboard, there is a problem that the product or goods may sway sideways during transportation. Furthermore, in recent years, there has been a demand for fixing and packaging a wide variety of products with different shapes and sizes in containers on the same packaging line, but the technology of Patent Document 1 requires a holding member that matches the product, making it difficult to package them on the same packaging line. The present technology aims to provide a sheet that can prevent lateral shaking of products or goods packaged in a container.

[0005] The present technology provides a sheet dotted with protrusions, wherein when an object is pressed against the protrusions and the protrusions are crushed, the protrusions retain a shape where the protrusions are completely crushed or partially crushed by the object, and the object is fixed by the protrusions in their crushed shape and / or the protrusions that maintain their 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 protrusions may be circular. In the sheet, the cross-sectional shape of the protrusions may be rectangular. In the sheet, the cross-sectional shape of the protrusions may be polygonal. In the sheet, the protrusions may be single-step protrusions. In the sheet, the protrusions may be multi-step protrusions. When the object is pressed against the multi-step protrusions, the protrusions in the steps that abut the object are easily crushed, and the sheet may retain the shape crushed by the object. The sheet can return to the original shape of the convex portions before being crushed by applying an external force to the back side of the convex portions in the crushed shape. When the sheet returns to the original shape of the convex portions before being crushed, an object can be pressed against the convex portions, and when the convex portions are crushed, the convex portions maintain their entirely crushed shape or their partially crushed shape by the object, and the object can be fixed by the crushed convex portions and / or the convex portions that maintain their original, uncrushed shape. The present technology also provides a packaging material including the sheet.

[0006] This technology makes it possible to provide a sheet that can prevent lateral shaking of packaging objects, such as products, packed in a container.

[0007] 12 is a perspective view showing an example of a sheet dotted with protrusions according to the present embodiment; FIG. 13 is a plan view of a sheet 10 dotted with protrusions according to the present embodiment; FIG. 14 is a cross-sectional view taken along line A-A in FIG. 2; FIG. 15 is a perspective view of a sheet 40 dotted with protrusions according to the present embodiment; FIG. 16 is a perspective view of a sheet 50 dotted with protrusions according to the present embodiment; FIG. 17 is a cross-sectional view taken along line A-A in FIG. 6; FIG. 18 is a plan view of a sheet 50 dotted with protrusions according to the present embodiment; FIG. 19 is a perspective view of a sheet 50 dotted with protrusions according to the present embodiment; FIG. 20 is a cross-sectional view taken along line A-A in FIG. 12; FIG. 21 is a plan view of a sheet 50 dotted with protrusions according to the present embodiment; FIG. 22 is a cross-sectional view taken along line A-A in FIG. 12; FIG. 23 is a plan view of a sheet 50 dotted with protrusions according to the present embodiment; FIG. 24 is a perspective view of a sheet 50 dotted with protrusions according to the present embodiment; FIG. 25 is a cross-sectional view taken along line A-A in FIG. 12; 17A and 17B show a two-layer sheet comprising layers A and B according to the present embodiment. FIG. 17B shows a three-layer sheet comprising layers A, B, and A according to the present embodiment. FIG. 17C shows a three-layer sheet comprising layers A, B, and C according to the present embodiment. FIG. 17C shows a perspective view of an object P pressed against sheet 60. FIG. 17B shows a cross-sectional view of line A-A in FIG. 17B. FIG. 17C shows a photograph of completely crushed convex portions 51A after an object is pressed against sheet 50, taken from the back side of the surface of sheet 50 that abuts against the object. FIG. 17C shows a photograph of the back side of convex portions 51A after a finger is pressed into the back of the crushed convex portions 51A to restore their original shape. FIG. 17D shows a photograph of convex portions 51A restored by a finger. FIG. 17D shows a perspective view of the obtained sheet 50. FIG. 17C shows a photograph of convex portions 51 scattered on the surface of sheet 50 after a rectangular metal P is pressed against sheet 50 to crush them. FIG. 17D shows a partially enlarged photograph showing the relationship between the rectangular metal P and the convex portions. 10 is a photograph showing a state in which a wrench S is pressed against a sheet 50 to crush protrusions 51 scattered on the surface of the sheet 50. FIG. 11 is a partially enlarged photograph showing the relationship between the wrench S and the protrusions.

[0008] Preferred embodiments of the present technology will be described below. Note that 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, a numerical range indicated using "to" indicates a range that includes the numerical values ​​described before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper or lower limit of a numerical range of a certain stage may be replaced with the upper or lower limit of a numerical range of another stage. Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more types.

[0009] The present technology will be described in the following order: 1. First embodiment (example of sheet) (1) Structure of sheet (2) Manufacturing method of sheet (3) Use 2. Examples

[0010] 1. First embodiment (example of a sheet)

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

[0012] FIG. 1 is a perspective view of a sheet 10 having scattered protrusions according to this embodiment. FIG. 2 is a plan view of the sheet 10 having scattered protrusions according to this embodiment. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. As shown in FIG. 1, the sheet 10 has a plurality of scattered protrusions 1. As shown in FIG. 2, the cross-sectional shape (peripheral shape) of the protrusions 1 is circular. As shown in FIG. 3, the protrusions 1 are single-stage protrusions having a single-stage structure. From the viewpoint of preventing lateral movement of an object during packaging, the ratio of the height H1 of the protrusions 1 to the height of the object (height H1 of the protrusions 1 / height of the object) is preferably 0.2 or more, more preferably 0.33 or more, and even more preferably 1 or more. Furthermore, the height H1 of the protrusions 1 may be preferably 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 ratio of the height H1 of the convex portion 1 to the diameter of the cross-sectional shape of the convex portion 1 (height H1 of the convex portion 1 / diameter of the cross-sectional shape of the convex portion 1) may be preferably 0.33 or more, more preferably 0.5 or more, and even more preferably 1 or more.

[0013] 4 is a perspective view of a sheet 40 having protrusions scattered thereon according to this embodiment. 41 The height H of the protrusion 41 is higher than the height H1 of the protrusion 1 of the sheet 10. 41 is the ratio of the cross-sectional shape of the convex portion to the diameter (the 41 Height H 41 / diameter of the cross-sectional shape of the protrusion 41) may be 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 having scattered protrusions according to this embodiment. FIG. 6 is a plan view of the sheet 50 having scattered protrusions according to this 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, the cross-sectional shape (peripheral shape) of the first and second protrusions in the protrusions 51 is circular. As shown in FIG. 7, the protrusions 51 are multi-step protrusions having a two-step structure with a first step 51f and a second step 51s. From the viewpoint of making the protrusions 51 easily crushable when an object is pressed against the protrusions 51, the protrusions are preferably multi-step protrusions having a multi-step structure with two or more steps. The protrusions may preferably have two or more steps, more preferably three or more steps, and even more preferably four or more steps. When an object is pressed against such a multi-step protrusion, the protrusions in the steps that come into contact with the object are easily crushed, and the shape crushed by the object is maintained. In order to prevent the object from shaking sideways during packaging, the height H of the protrusion 51 is 51 is the ratio to the height of the object (height H of the convex portion 51) 51 / height of the object) may be preferably 0.2 or more, more preferably 0.33 or more, and even more preferably 1 or more. 51 The height H of the protrusion 51 may be preferably 0.1 cm to 5 cm, more preferably 0.2 cm to 4 cm, and even more preferably 0.3 cm to 3 cm. 51 is the ratio of the diameter of the cross-sectional shape of the first step 51f of the convex portion 51 to the diameter of the cross-sectional shape of the first step 51f of the convex portion 51 (the height H of the convex portion 51 51 / diameter of the cross-sectional shape of the first step 51f of the convex portion 51) may be preferably 0.33 or more, more preferably 0.5 or more, and even more preferably 1 or more.

[0015] In addition, in order to make it easier for the convex portion 51 to be crushed when an object is pressed against the convex portion 51, the height H 51f is the height H of the protrusion 51 51 (the first step height H of the protrusion 51) 51f / H 51 ) is preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.5 or more. 51fThe first step height H 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 is the ratio of the diameter of the cross-sectional shape of the first step 51f of the convex portion 51 to the diameter of the first step H of the convex portion 51 51f The height H of the second step 51s of the protrusion 51 (the diameter of the cross section of the first step 51f of the protrusion 51) may be preferably 0.066 or more, more preferably 0.133 or more, and even more preferably 0.5 or more. 51s is the height H of the protrusion 51 51 (the second-stage height H of the protrusion 51) 51s / H 51 ) may be preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.5 or more. 51s The height H of the second step 51s of the protrusion 51 is 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 is the ratio of the diameter of the cross-sectional shape of the first step 51f of the convex portion 51 to the diameter of the cross-sectional shape of the first step 51f of the convex portion 51 (the height H 51s / diameter of the cross-sectional shape of the first step 51f of the convex portion 51) may be preferably 0.066 or more, more preferably 0.133 or more, and even more preferably 0.5 or more.

[0016] In the sheet of this embodiment, when an object is pressed against the protruding portions 51 and the protruding portions 51 are crushed, the protruding portions 51 maintain a shape in which the entire protruding portions 51 are crushed by the object. Furthermore, when the protruding portions 51 are crushed, the protruding portions 51 maintain a shape in which only a portion of the protruding portions 51 is crushed by the object. The sheet of this embodiment is resistant to returning to its original shape after being crushed, making it possible to sandwich and fix the object in a crushed shape. FIG. 8 is a plan view photograph showing the state in which the object P is pressed against the protruding portions 51 of the sheet and the protruding portions 51 are crushed. FIG. 9 is a perspective photograph showing the state in which the object P is pressed against the protruding portions 51 of the sheet and the protruding portions 51 are crushed. FIG. 10 is a perspective photograph showing the state of the protruding portions 51 after the object P is pressed against the protruding portions 51 of the sheet, the protruding portions 51 are crushed, and then the object P is removed. 8, 9, and 10, the convex portion 51A maintains the shape of the convex portion 51 when it is completely crushed. The convex portion 51B maintains the shape of the convex portion 51 when it is partially crushed. The convex portion 51C maintains its original shape when it is not crushed. As shown in FIGS. 8, 9, and 10, the object P is fixed by the convex portions 51A, 51B, and 51C. More specifically, as shown in FIG. 10, the object P is fixed by contact with the convex portion 51C, which maintains its original shape and is not crushed, adjacent to the convex portion 51A that has been pressed against it and has a completely crushed shape, thereby preventing the object P from swaying sideways. Furthermore, these convex portions 51B and 51C provide a cushioning effect against external impacts.

[0017] FIG. 11 is a perspective view of a sheet 60 dotted with protrusions according to this embodiment. FIG. 12 is a plan view of the sheet 60 dotted with protrusions according to this embodiment. FIG. 13 is a cross-sectional view taken along line A-A in FIG. 12. As shown in FIG. 11, the sheet 60 is dotted with a plurality of protrusions 61. The cross-sectional shape of the protrusions according to this embodiment may be rectangular, such as a square or a rectangle, or may be polygonal, such as a pentagon or a hexagon. As shown in FIG. 12, the cross-sectional shape (peripheral shape) of the protrusions 61 dotted on the sheet 60 is quadrangular. As shown in FIG. 13, the protrusions 61 are multi-step protrusions having a three-step structure consisting of a first step 61f, a second step 61s, and a third step 61t. When an object is pressed against such a multi-step protrusion, the protrusions of the step that contacts the object are easily crushed and retain the crushed shape due to the object. From the viewpoint of preventing the object from swaying sideways during packaging, the height H of the protrusions 61 is set to 1 / 2. 61 is the ratio to the height of the object (height H of the convex portion 61) 61 / height of the object) may be preferably 0.2 or more, more preferably 0.33 or more, and even more preferably 0.5 or more. 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 is the ratio of the length of the side of the cross-sectional shape of the convex portion 61 (the height H of the convex portion 61 61 / the length of the side of the cross-sectional shape of the protrusion 61) may be preferably 0.33 or more, more preferably 0.5 or more, and even more preferably 1 or more.

[0018] In addition, the first step height H of the protrusion 61 61f The first step height H 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 is the ratio of the length of the side of the cross-sectional shape of the first step 61f of the convex portion 61 (the first step height H of the convex portion 61) 61fThe height H of the second step 61s of the protrusion 61 (length of the side of the cross section of the first step 61f of the protrusion 61) may be preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. 61s is the height H of the protrusion 61 61 (the second-stage height H of the protrusion 61) 61s / H 61 ) may be preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. 61s The height H of the second step of the protrusion 61 is 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 is the ratio of the length of the side of the cross-sectional shape of the first step 61f of the convex portion 61 (the height H of the second step of the convex portion 61 61s The height H of the third step 61t of the protrusion 61 (length of the side of the cross section of the first step 61f of the protrusion 61) may be preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. 61t is the height H of the protrusion 61 61 (the third step height H of the protrusion 61) 61t / H 61 ) may be preferably 0.066 or more, more preferably 0.2 or more, and even more preferably 0.33 or more. 61t The height H of the third step 61t of the protrusion 61 is 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. 61t is the ratio of the length of the side of the cross section of the first step 61f of the convex portion 61 to the length of the side of the cross section (the height H of the third step 61t of the convex portion 61) 61t / the length of the side of the cross-sectional shape of the first step 61f of the protrusion 61) may be 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 may be a multi-layer sheet having a plurality of layers, such as two or three layers, stacked together. Hereinafter, the single-layer sheet will be described first, and then the multi-layer sheet will be described.

[0020] [Single layer sheet]

[0021] The monolayer 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, the inclusion of a biomass material makes it possible to obtain convex portions scattered on the molded sheet that are easy to crush when crushed and difficult to return to their original shape after crushing.

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

[0023] The starch material can be raw starch, including, for example, starch from underground sources and starch from above ground sources. Underground starch is starch accumulated underground, such as in rhizomes or roots. Examples of underground starches include, but are not limited to, tapioca starch (cassava starch), potato starch, sweet potato starch, kudzu starch, and bracken starch.

[0024] Terrestrial starch refers to starch accumulated above ground, for example, starch accumulated in seeds, etc. Examples of terrestrial 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, ground starch is preferably used.

[0026] The starch material may be a modified starch (i.e., modified starch), particularly a modified ground 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, xanthogen acetate-esterified starch, nitrate-esterified starch, urea phosphate-esterified starch, phosphate-esterified starch, phosphate-crosslinked starch, formaldehyde-crosslinked starch, acrolein-crosslinked starch, and epichlorohydrin-crosslinked starch.

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

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

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

[0030] 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 blended with a thermoplastic resin, the moisture content of the starch may preferably be 3% or less.

[0031] The cellulose material used in this embodiment may be paper, paper pulp, cotton, or ground cloth.

[0032] The particle size D50 (median diameter) of the cellulose material may be, 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). Having the cellulose material have a particle size within the above numerical range can contribute to improving the dispersibility of the cellulose material contained in the thermoplastic resin.

[0033] Among 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 percentage of the number of cellulose fibers is calculated by determining, by wet measurement using the laser diffraction particle size analyzer, the percentage of the number of cellulose fibers having a particle size of 0 μm to 9.8 μm (hereinafter referred to as the "first percentage") and the percentage of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm (hereinafter referred to as the "second percentage") among the total number of cellulose fibers in the cellulose material, and then subtracting the first percentage from the second percentage. 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 analyzer in the wet measurement.

[0034] In this embodiment, it is particularly preferred that the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm account 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 percentage of the number of cellulose fibers is calculated by determining, by wet measurement using the laser diffraction particle size analyzer, the percentage of the number of cellulose fibers having a particle size of 0 μm to 110.6 μm (the "second percentage") and the percentage of the number of cellulose fibers having a particle size of 0 μm to 998.4 μm (hereinafter referred to as the "third percentage") among the total number of cellulose fibers in the cellulose material, and then subtracting the second percentage from the third percentage. 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 analyzer during the wet measurement.

[0035] A cellulose material having the above particle size distribution can be produced, for example, by treating pulp with a chemical such as an acid. An example of a cellulose material having the above particle size distribution is KC Flock W400 (Nippon Paper Industries Co., Ltd.). The use of cellulose powder having the above particle size distribution results in better formability when producing a sheet.

[0036] In particular, by having the number of cellulose fibers having a particle size of 9.8 μm to 110.6 μm account for 80% to 100%, and even more preferably 85% to 100%, of the total number of cellulose fibers constituting the cellulose powder, it is possible to prevent tears or holes from occurring in the sheet obtained by molding the thermoplastic resin. In order to prevent tears or holes from occurring in the sheet, it is particularly preferred that the number of cellulose fibers having a particle size of 110.6 μm to 998.4 μm account for 0% to 20%, and even more preferably 0% to 15%, of the total number of cellulose fibers constituting the cellulose powder.

[0037] In another embodiment, the cellulose powder may have a particle size in which 90% or more pass through a 100-mesh mesh. In this embodiment, more preferably, the cellulose powder has a particle size in which 90% or more pass through a 100-mesh mesh, 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 sieve method, specifically as follows. That is, 10 g of a sample is placed on a 100-mesh standard sieve, a tray and a lid are attached to the standard sieve, and the sample is shaken for 40 minutes in a low-tap shaker. Then, the particle size is calculated from the sample mass (10 g) and the mass of the residue on the sieve using the following formula: Particle size (%) = [(sample mass (g) - residue on the sieve (g)) / sample mass (g)] x 100

[0039] The apparent specific gravity is measured as follows. That is, 10 g of sample is accurately weighed on a balance and placed in a 50 ml measuring cylinder. The bottom of the measuring cylinder is placed on a table covered with a rubber sheet and struck, taking care not to scatter the sample. The striking operation is continued until the sample no longer clogs the cylinder. After the striking operation, 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 (10 g) / volume (ml)

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

[0041] In this embodiment, from the viewpoint of obtaining a sheet in which the convex portions scattered across the formed sheet are easy to crush and difficult to return to their original shape after crushing, the content of the biomass material is preferably 4% by mass or more and 95% by mass or less, more preferably 6% by mass or more and 93% by mass or less, and even more preferably 8% by mass or more and 90% by mass or less, relative to the mass of the resin composition.

[0042] The thermoplastic resin used in the monolayer sheet according to this embodiment may be a polyolefin resin, a polyester resin, or a mixture of these resins. The thermoplastic resin may also be a polystyrene resin. The thermoplastic resin may also contain a biodegradable material to prevent a decrease in biodegradability.

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

[0044] The polyethylene resin may be, for example, a low-density polyethylene resin (LDPE: Low Density Polyethylene), a high-density polyethylene resin (HDPE: High Density Polyethylene), a very low-density polyethylene resin (VLDPE: Very Low Density Polyethylene), a linear low-density polyethylene resin (LLDPE: Linear Low Density Polyethylene), an ethylene-vinyl acetate copolymer (EVA resin), or an ethylene copolymer, or an ultra-high molecular weight polyethylene resin (UHMW-PE: Ultra High Molecular Weight Polyethylene), or a combination thereof.

[0045] The polyolefin resin may preferably be a biomass-derived polyolefin resin (e.g., a biomass-derived polyethylene resin), such as 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-catalyzed polyethylene resin or polypropylene resin, or a combination thereof. The polystyrene resin may be a metallocene-catalyzed polystyrene resin.

[0047] The polyester resin is a polymer formed by polymerizing monomers via ester bonds, and may be, for example, polyethylene terephthalate resin (PET), polyethylene naphthalate resin (PEN), polybutylene terephthalate resin (PBT), polylactic acid resin (PLA), polycarbonate resin (PC), polybutylene adipate terephthalate resin (PBAT), polybutylene succinate resin (PBS), polyhydroxyalkanoate resin (PHA), or a combination of two or more thereof.

[0048] The polystyrene resin is a polymer formed by polymerization of a styrene monomer. Examples of the polystyrene resin include polystyrene resin, rubber-reinforced polystyrene resin (high impact polystyrene resin, HIPS), acrylonitrile-styrene copolymer (AS resin), methacrylate ester-styrene copolymer, acrylonitrile-acrylic rubber-styrene copolymer, and acrylonitrile-ethylene-propylene-styrene copolymer, or a combination of two or more of these.

[0049] In the present embodiment, the type of thermoplastic resin may be appropriately selected by a person skilled in the art depending on the packaging application, and a thermoplastic resin having a low processing temperature is preferred. For example, in the case of a sheet used for packaging food products, the thermoplastic resin is 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 lowered. The melting point of the thermoplastic resin is preferably 90°C or higher, and more preferably 95°C or higher.

[0051] The thermoplastic resin may be in the form of pellets. The content of the thermoplastic resin is preferably 3% by mass or more and 95% by mass or less, more preferably 5% by mass or more and 93% by mass or less, and even more preferably 8% by mass or more and 90% by mass or less, based on the mass of the resin composition.

[0052] Examples of the biodegradable material include cellulose derivatives such as methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, and hydroxybutyl methyl cellulose; hydrophilic polymer materials such as polyvinyl alcohol, carboxymethyl cellulose, polyacrylic acid polymers, and polyacrylamide; emulsions of various acrylates, ethylene / vinyl acetate copolymers, and polyurethanes; and aliphatic polyester resins such as caprolactone, polylactic acid, polybutylene adipate, polybutylene succinate, and polyhydroxybutyrate-valerate copolymers.

[0053] The monolayer 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 additives that have a melting point lower than that of the thermoplastic resin and melt at relatively low temperatures. Such low-melting additives preferably melt at 100°C or below, more preferably between 60 and 100°C. Ester compounds that are liquid or solid at room temperature are preferred. Specific examples of low-melting 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 preferred. Low-melting additives melt at relatively low temperatures, have viscosity, and can function to entangle and adhere to the biomass material powder.

[0054] The low melting point additive may be blended in a content ratio 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 the biomass material.

[0055] The low melting point additive may be contained in the resin composition, for example, preferably in an amount of 0.1% by mass to 5% by mass, more preferably 0.1% by mass to 3% by mass, relative to the mass of the resin composition.

[0056] The resin composition may also contain a high-melting-point additive having a melting point higher than that of the low-melting-point additive. Such a high-melting-point additive has a melting point higher than that of the low-melting-point additive, preferably in the range of 100 to 150°C, solidifies before the low-melting-point additive, and has 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. Specific examples of such high-melting-point additives include magnesium stearate, zinc stearate, calcium stearate, aluminum stearate, sodium lauryl sulfate, magnesium lauryl sulfate, potassium benzoate, sodium benzoate, and sodium stearyl fumarate.

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

[0058] As another additive, a compatibilizer can be used to improve the affinity between the biomass material and the thermoplastic resin. 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, in particular a carboxylic acid anhydride-modified polyolefin or an olefin-based comonomer.

[0060] The carboxylic acid anhydride constituting the carboxylic acid anhydride-modified polyolefin may preferably be maleic anhydride. The compatibilizer may be, for example, a maleic anhydride-grafted polyolefin resin, more particularly, one or a combination of two or more 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 contained in the resin composition in a content of, for example, 0.1% by mass to 10% by mass, more preferably 1.0% by mass to 5.0% by mass, relative to the mass of the resin composition.

[0062] As other additives, colorants may be used.

[0063] The colorant can be used to impart color to the resin composition, and examples of the colorant include titanium oxide, carbon black, dyes, and pigments.

[0064] As other additives, inorganic fillers can be used. Examples of inorganic fillers include inorganic powders. As inorganic powders, for example, shell powders, mineral powders, etc. are preferably used. The specific gravity of the inorganic powders used is preferably 2.5 g / cm. 3 More preferably, 2.55 g / cm 3 More preferably, 2.6 g / cm 3 More preferably, 2.65 g / cm 3 It may be more than that.

[0065] Shell powder refers to shells crushed into powder. Shells are not particularly limited, and shells from shellfish such as scallops, oysters, surf clams, abalone, mussels, littleneck clams, and cockles can be used. Shell powder can be obtained, for example, by cleaning and sterilizing shells discarded from food factories and then crushing them. Shell powder can also be obtained from shells of shellfish not intended for food use. The method for crushing shells is not particularly limited, and any known crushing method can be appropriately selected and adopted, and can be wet or dry. Alternatively, shells can be pre-crushed in a coarse crusher and then powdered in a crusher. Specific examples of coarse crushers include jaw crushers, cone crushers, cutter mills, and hammer crushers. Examples of crushers include roll mills, stamp mills, hammer mills, ball mills, vibrating ball mills, roller mills, and vertical mills. The shell powder is preferably scallop shell powder. Examples of scallop shell powder include unbaked scallop shell powder and baked scallop shell powder. Unbaked scallop shell powder is made by powdering natural scallop shells and is in an unbaked state, and its main component (about 96%) is usually calcium carbonate. Unbaked scallop shell powder is commercially available.

[0066] Examples of mineral powders include clay mineral powders. Both natural and synthetic clay mineral powders can be used. 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. Shell powder alone may be used as the inorganic powder, or mineral powder alone may be used, or a mixture of shell powder and mineral powder may be used.

[0067] Furthermore, the other components may include, for example, an antioxidant, a crosslinking agent, an ultraviolet absorber, a foaming agent, an impact resistance agent, etc. Commercially available additives may be used as these additives.

[0068] [Multi-layer sheet]

[0069] Next, the multilayer sheet according to this embodiment will be described with reference to the drawings. FIG. 14 shows a two-layer sheet according to this embodiment, composed of layers A and B. In the two-layer multilayer sheet shown in FIG. 14, layer A is formed from a resin composition containing a polyolefin resin. The polyolefin resin has been described above for the single-layer sheet, and therefore further description will be omitted. In layer A, the polyolefin resin contained in the resin composition may preferably be 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, or even 100% by mass, relative to 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 above for the single-layer sheet. The resin composition has also been described above, and therefore further description will be omitted. In the two-layer multilayer sheet, either layer A or layer B may be on the convex surface side.

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

[0071] (2) Sheet manufacturing method

[0072] [Method of manufacturing single-layer sheet]

[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 an external heating unit, and the biomass material is dried while heating the inside of the container with the heating unit, 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 dotted with convex portions.

[0074] The method for producing 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 step (S1)>

[0076] In the biomass material drying step (S1), the biomass material is placed in a container. The container containing the biomass material is equipped with an external heat generating unit that heats the interior of the container. Examples of such containers include a heated mixer having a heating jacket around a cylindrical container made of stainless steel or steel. In such a heated mixer, the outer periphery of the container that contains the biomass material is covered with a heating jacket. A stirring blade is provided inside the container. A heat transfer medium such as oil, hot water, or heated steam is filled inside the heating jacket, and the heating jacket can function as a heat generating unit. The heating jacket heats the container by heating the inner surfaces of the container, such as the wall surface, lid surface, and bottom surface. The heating jacket heats the inner surface of the container so that no insufficiently heated areas exist. By preventing any insufficiently heated areas from existing on the inner surface of the container, condensation of the moisture in the biomass material evaporated by heating is suppressed when it comes into contact with the insufficiently heated areas. By suppressing condensation on the inner surface of the heated mixer, biomass materials such as starch can be prevented from gelatinizing and adhering to the inner surface of the heated mixer. The biomass material contained in the container's storage section is dried in the heated storage section. During drying of the biomass material, the biomass material can be prevented from gelatinizing and drying efficiency can be improved by constantly moving the biomass material using stirring blades. The shape of the stirring blades 12 can be selected from any shape, including propeller blades, paddle blades, inclined paddle blades, turbine blades, screw blades, anchor blades, ribbon blades, and large lattice blades. This type of heated mixer is also called an externally heated jacket mixer.

[0077] In this step, 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 at preferably 500 to 2000 rpm, more preferably 750 to 1750 rpm, and even more preferably 1000 to 1500 rpm.

[0079] In this step, the time for drying 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 may be preferably 10 to 30 minutes, more preferably 15 to 30 minutes, and even more preferably 15 to 25 minutes.

[0080] This process prevents the biomass material from adhering to the inner surface of the container in which it is stored. When the biomass material is heated in the container, the moisture contained in the biomass material evaporates. The evaporated moisture comes into contact with areas of the container's inner surface, such as the 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 stored in the container adheres to the inner surface of the container where condensation has occurred, the biomass material is heated in the presence of moisture. For example, when the biomass material is starch, moisture penetrates into the molecular chains of the starch upon heating, loosening the molecular structure and causing swelling (gelatinization), resulting in the formation of granular matter known as "white grains." "White grains" have absorption peaks derived from starch in the infrared absorption spectrum. Examples of such absorption peaks include peaks derived from OH bonds, which exist in the range of 3000 to 3500 cm-1. Furthermore, "white grains" do not stain with iodine dye. Typically, starch particles have a major axis of 10 to 20 μm, whereas granular materials known as "white grains" have a major axis of 100 to 200 μm, larger than ungelatinized starch particles. Ungelatinized starch refers to starch that has not been gelatinized before heating or even after heat-drying. Such "white grains" can cause mesh clogging or white grain contamination during extrusion molding of sheets or films, leading to brown discoloration and holes in the resulting molded body. In this process, the interior of the container is heated by an external heating element, preventing the occurrence of condensation and adhesion of the biomass material to the container's inner surface by eliminating any areas on the container's inner surface where the temperature is insufficient. Preventing adhesion of the biomass material to the container's inner surface in this way reduces the occurrence of white grains and enables the efficient production of high-quality molded bodies. Furthermore, agitating the container to prevent the biomass material from accumulating in one place is also preferable to prevent adhesion of the biomass material to the container's inner surface.

[0081] Although the above method uses an external heating jacket mixer, a heating jacket vacuum dryer may also be used in the biomass material drying step (S1) of this embodiment. This dryer preferably has an external heating jacket and a stirring blade installed inside the container, and the biomass material can be dried by creating a vacuum inside the container.

[0082] When a heating jacket type vacuum dryer is used, 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 degree of vacuum inside the container is preferably set to 5 kPa to 30 kPa, more preferably 5 kPa to 25 kPa, and even more preferably 5 kPa to 20 kPa.

[0084] In this process, the time for drying 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 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 step (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 a resin composition. In this step, 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 that is a mixture of powdered biomass material and pelleted thermoplastic resin. Alternatively, the dried biomass material and the thermoplastic resin may be simultaneously fed into an extruder via a feeder, and the rotation speed, mixing time, temperature, etc. may be controlled to uniformly knead and mix the biomass material and the thermoplastic resin by heating and kneading. The mixture of the biomass material and the thermoplastic resin in a melt-kneaded state present in the extruder may be used as a resin composition. Furthermore, the melt-kneaded mixture of the biomass material and the thermoplastic resin may be extruded from the extruder, cooled, and pelletized to form a resin composition. A single-screw extruder or a twin-screw extruder may be used as such an extruder. When the biomass material and the thermoplastic resin are fed into the extruder, additives may be added at the same time. Examples of such additives include low-melting point additives and high-melting point additives. Alternatively, the biomass material, the thermoplastic resin, and the additives may be added individually via feeders in predetermined amounts.

[0087] When the biomass material and the thermoplastic resin are mixed in the extruder, the heat processing 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 deterioration and discoloration of the materials. For example, the heat processing temperature (cylinder temperature) may be set to 100 to 190°C.

[0088] <Molding process (S3)>

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

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

[0091] In the method for producing a monolayer sheet according to this embodiment, a biomass material cooling step (S4) may be performed between the biomass material drying step (S1) and the resin composition preparation step (S2). This step may be performed using, for example, a production apparatus having a heating mixer, a cooling mixer, and an extruder.

[0092] The biomass material and the thermoplastic resin are heated and stirred in a heating mixer. The biomass material, the thermoplastic resin, and the low-melting-point additive may also be heated and stirred in the heating mixer. The mixture of the biomass material and the thermoplastic resin, etc. may then be transferred to a cooling mixer and cooled while being stirred in the cooling mixer to a temperature equal to or higher than the melting temperature of the low-melting-point additive and close to the melting temperature. The mixture of the biomass material and the thermoplastic resin, etc. may also be cooled without stirring.

[0093] [Method of manufacturing multilayer sheet]

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

[0095] The method for producing 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). The biomass material drying step (S1), the resin composition preparation step (S2), and the biomass material cooling step (S4) are the same steps as those in the method for producing a single-layer sheet, and therefore their explanations are omitted. The multilayer extrusion molding step (S6) will be described below.

[0096] <Multilayer extrusion molding process (S6)>

[0097] In the multilayer extrusion molding step (S6), a resin composition different from the resin composition is extruded and molded so that different resin layers are laminated together to obtain a laminate. The laminate can be obtained, for example, using a multilayer coextrusion molding machine. The multilayer coextrusion molding machine may have an extruder for layer A, an extruder for layer B, an extruder for layer C, a feed block, and a die. The multilayer coextrusion molding machine coextrudes a three-layer structure sheet in which layer A, layer B, and layer C are laminated, with layer B containing a biomass material as the middle layer and layer A and layer C as the surface layers. The extruder for layer B extrudes the resin composition prepared in the resin composition preparation step (S2), and the extruders for layer A and layer C each extrude a type of thermoplastic resin composition different from the resin composition extruded from the extruder for layer B. When producing a two-layer sheet consisting of layer A and layer B, for example, an extruder for layer A and an extruder for layer B are used to form the sheet. Furthermore, when producing a three-layer sheet in which Layer B is the middle 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 three-layer sheet is formed by supplying the resin composition used in the extruder for Layer B to the extruder for Layer C. To dot the sheet with convex portions, the same method as for a single-layer sheet may be used, and the convex portions can be formed simultaneously in Layer A, Layer B, and Layer C.

[0098] (3) Purpose

[0099] The sheet according to this embodiment can secure an object to be transported in a packaging container during transport of goods or products, preventing lateral shaking due to vibrations and the like. Furthermore, regardless of the shape of the object, when the object is packed in the container, it can be pressed against the convex portions of the sheet, crushing all or part of the convex portions. The object can be held in place by the convex portions that are fully crushed, partially crushed, or retain their original shape. In other words, there is no need to prepare cushioning material in advance to accommodate the shape of the object to be transported. Figure 17 is a perspective view showing an object P pressed against the sheet 60. Figure 18 is a cross-sectional view taken along line A-A in Figure 17. As shown in Figures 17 and 18, the object P pressed against the sheet 60 is secured by the completely crushed convex portions 61A, partially crushed convex portions 61B, and convex portions 61 that retain their original shape, thereby suppressing lateral shaking due to vibrations and the like during transport.

[0100] The sheet according to this embodiment can restore the original shape of the convex portions before being crushed by applying an external force from the back side of the crushed convex portions. This will be explained using photographs. Fig. 19 is a photograph of the convex portions 51A completely crushed after pressing an object against the sheet 50, taken from the back side of the surface of the sheet 50 that abuts against the object. Fig. 20 is a photograph of the back side of the crushed convex portions 51A after a finger is pressed into the crushed portion from the back side of the crushed convex portions 51A to restore the convex shape. Fig. 21 is a photograph of the convex portions 51A restored to their original shape by a finger.

[0101] When the sheet according to this embodiment returns to the original shape of the convex portions before being crushed, an object is pressed against the convex portions, and when the convex portions are crushed, the convex portions are held in place by the object, either entirely or partially crushed, and the object is secured by the crushed convex portions and / or the convex portions that maintain their original, uncrushed shape. In other words, the sheet according to this embodiment has the function of preventing the object from swaying sideways even after multiple uses. This embodiment also provides packaging materials including the sheet. For example, a packaging box and the sheet can be used as packaging materials to secure merchandise or products and prevent them from swaying sideways during transport.

[0102] The present technology can also employ the following configurations. [1] A sheet having protrusions scattered thereon, wherein when an object is pressed against the protrusions and the protrusions are crushed, the protrusions retain a shape in which the protrusions are entirely crushed or a shape in which only a portion of the protrusions is crushed by the object, and the object is fixed by the protrusions in their crushed shape and / or the protrusions that maintain their 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 protrusions is circular. [4] The sheet according to any one of [1] to [3], wherein the cross-sectional shape of the protrusions is rectangular. [5] The sheet according to any one of [1] to [4], wherein the cross-sectional shape of the protrusions is polygonal. [6] The sheet according to any one of [1] to [5], wherein the protrusions are single-step protrusions. [7] The sheet according to any one of [1] to [6], wherein the convex portions are multi-step convex portions. [8] The sheet according to [7], wherein when the object is pressed against the multi-step convex portions, the convex portions of the steps that come into contact with the object are easily crushed and maintain the crushed shape by the object. [9] The sheet according to any one of [1] to [8], wherein when an external force is applied to the back side of the convex portions in their crushed shape, they return to the shape of the convex portions before being crushed.

[10] The sheet according to [9], wherein when the convex portions return to their shape before being crushed, when an object is pressed against the convex portions and the convex portions are crushed, the convex portions maintain the shape of the convex portions where the convex portions are entirely crushed or where the convex portions are partially crushed by the object, and the object is fixed by the convex portions in their crushed shape and / or the convex portions that maintain their original shape without being crushed.

[11] The sheet according to any one of [1] to

[10] , wherein a packaging material including the sheet according to any one of [1] to

[10] , wherein ...

[0103] 2. Working Example

[0104] The present technology will be described in more detail below based on 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 heating mixer (external heating jacket 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 (corn starch ratio before drying), and the mixture was dried for 20 minutes at a heating jacket temperature of 150° C. The moisture content of the corn starch after drying was 2%. Corn starch, 29.57 parts by weight of polypropylene (product name: CS356M, manufactured by SunAllomer Co., Ltd.), 1.07 parts by weight of zinc stearate, 3.27 parts by weight of magnesium stearate, 3 parts by weight 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 weight of white pigment were compounded using a twin-screw extruder (Ikegai Corporation, PCM30, screw diameter: 30φ) to obtain pellets. The resulting pellets were fed via a hopper into the B layer extruder of a multilayer co-extrusion molding machine (manufactured by LAB TECH Engineering Co., Ltd.).

[0107] In addition, a polypropylene resin composition (product name: EG6D, manufactured by Japan Polypropylene Corporation) was supplied via a hopper to the extruder for layer A of a multilayer coextrusion molding machine (manufactured by LAB TECH Engineering Co., Ltd.), and a polypropylene resin composition (product name: EG6D, manufactured by Japan Polypropylene Corporation) was supplied via a hopper to the extruder for layer C. The resin compositions supplied to the extruder for layer A, the extruder for layer B, and the extruder for layer C were coextruded to obtain a multilayer sheet with a three-layer structure having layer B as the middle layer. The thickness of the obtained multilayer sheet was 0.5 mm.

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

[0109] The obtained multilayer sheet was placed in a vacuum forming machine (WAKITEC Using an FVS-500P (Wakisaka Engineering Co., Ltd.), a sheet 50 was formed with circular cross-sectional projections scattered on the surface of the layer A side. FIG. 22 is a perspective photograph of the resulting sheet 50. A rectangular metal P was pressed against the resulting sheet 50 to crush the scattered projections 51 on the surface of the sheet 50. FIG. 23 is a photograph showing the state in which the rectangular metal P was pressed against the sheet 50 to crush the scattered projections 51 on the surface of the sheet 50. As shown in FIG. 23, the rectangular metal P is surrounded by completely crushed projections 51A, partially crushed projections 51B, and projections 51C that maintain their original shape. FIG. 24 is a partially enlarged photograph showing the relationship between the rectangular metal P and the projections. As shown in FIG. 24, the rectangular metal P is sandwiched and fixed between completely crushed projections 51A (hidden by the metal P), partially crushed projections 51B, and projections 51C that maintain their original shape.

[0110] A wrench S was then pressed against the resulting sheet 50 to crush the scattered protrusions 51 on the surface of the sheet 50. FIG. 25 is a photograph showing the state in which the wrench S was pressed against the sheet 50 to crush the scattered protrusions 51 on the surface of the sheet 50. As shown in FIG. 25, the wrench S is surrounded by completely crushed protrusions 51A, partially crushed protrusions 51B, and protrusions 51C that maintain their original shape. FIG. 26 is a partially enlarged photograph showing the relationship between the wrench S and the protrusions. As shown in FIG. 26, the wrench S is sandwiched and fixed between the completely crushed protrusions 51A, partially crushed protrusions 51B, and protrusions 51C that maintain their original shape. In this way, the sheet according to this embodiment can also fix objects with complex shapes.

[0111] [Vibration test]

[0112] A 350 g metal sample (10 cm long x 9.2 cm wide x 1.5 cm thick) was pressed by hand onto the obtained sheet 50, and the protrusions were crushed to fix the metal sample. The sheet 50 was moved back and forth 20 times in 10 seconds, 3 cm to the left and 3 cm to the right, in parallel. It was confirmed that the position of the metal sample did not move 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 dotted with protrusions was formed using a 0.4 mm thick single-layer polypropylene sheet (manufactured by I-Sheet Kogyo Co., Ltd.) in the same manner as in Example 1. A metal sample (10 cm long x 9.2 cm wide x 1.5 cm thick) weighing 350 g was pressed by hand onto the obtained sheet in an attempt to crush the protrusions and fix the metal sample, but the protrusions could not be crushed.

[0115] The configurations, methods, steps, shapes, materials, and numerical values, etc., described in the above-described embodiments and examples are merely examples, and different configurations, methods, steps, shapes, materials, and numerical values, etc., may be used as necessary.

[0116] Furthermore, the configurations, methods, processes, shapes, materials, numerical values, etc. of the above-described embodiments and examples can be combined with one another without departing from the spirit of the present embodiments.

[0117] Furthermore, in this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper limit or lower limit of a numerical range in a certain stage may be replaced with the upper limit or lower limit of a numerical range in another stage. Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination of two or more types.

[0118] 1 convex portion 10 sheet 40 sheet 41 convex portion 50 sheet 51 convex portion 51f first convex portion 51s second convex portion 60 sheet 61 convex portion 61f first convex portion 61s second convex portion 61t third convex portion

Claims

1. A sheet with scattered protrusions, The aforementioned sheet is formed from a resin composition containing a starch material and a thermoplastic resin. 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 claim 1, wherein the cross-sectional shape of the convex portion is circular.

3. The sheet according to claim 1, wherein the cross-sectional shape of the convex portion is rectangular.

4. The sheet according to claim 1, wherein the cross-sectional shape of the convex portion is polygonal.

5. The sheet according to claim 1, wherein the aforementioned protrusion is a single-stage protrusion.

6. The sheet according to claim 1, wherein the aforementioned protrusion is a multi-stage protrusion.

7. The sheet according to claim 6, 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.

8. 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.

9. The sheet according to claim 8, 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.

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