Folded lined plastic sheet

Abstract

To provide a plastic sheet with folding lines for preventing a packaging case from cracking even if the packaging case is subjected to an impact due to being dropped when the packaging case is assembled by folding the plastic sheet and used for display and sale, storing heavy articles in the packaging case. [Solution] A plastic sheet 1 of a predetermined shape has folding lines 2 formed on its surface, and the folding lines 2 are formed by pressing a scoring blade with a curved or flat cutting edge cross section against the sheet surface to form pressed scores, and multiple notches 3 that intersect with the folding lines 2 are arranged at predetermined intervals along the folding lines 2 on the sheet surface on which the folding lines 2 are formed.

Description

[Technical field]

[0001] This invention relates to a plastic sheet with fold lines that is suitable for storing cosmetics, daily necessities, and other items in a packaging case that is assembled by punching out a sheet molded from highly transparent plastic into a predetermined shape and folding it along the fold lines formed on the surface, and then selling or displaying the package. [Background technology]

[0002] 2. Description of the Related Art Packaging cases assembled by folding transparent plastic sheets (hereinafter simply referred to as "sheets") into a box shape are used as containers for storing items such as cosmetics and daily necessities and for displaying and selling them.

[0003] Conventionally, a known type of plastic sheet with fold lines that can be assembled into packaging cases has a structure in which the fold lines are arranged in the form of fine rope-like ridges on the bottom surface of the plastic sheet, so-called "rope-patterned fold lines," intended to improve the foldability and bending strength of the plastic sheet with fold lines on its surface (see, for example, Patent Document 1).

[0004] Furthermore, in order to obtain good easy-to-bend properties for a plastic sheet with fold lines to be assembled into a clear box, a method of processing fold lines is known in which mountain fold lines and valley fold lines are simultaneously formed at opposing positions on one side and the other side of the sheet, and grooves that are deeper than the valley fold lines are formed at predetermined intervals along and across the fold lines (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-292023 A [Patent Document 2] Japanese Patent Application Publication No. 8-244146 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the conventional creased plastic sheet, it is possible to fold the sheet smoothly along the creases and assemble it into a packaging case. In addition, a plastic sheet with fold lines has mountain folds and valley folds on both sides of the plastic sheet to be assembled into a clear box, and multiple deep grooves are provided in the valley fold lines.Since multiple grooves are formed in the valley fold lines, the springback tendency of the sheet is reduced, and the sheet can be easily assembled by standing it up at a right angle.

[0007] However, when the items stored in the packaging case are heavy, for example, heavy cosmetics or daily necessities such as cosmetic sheets soaked in cosmetic liquid, masks, shampoos, and conditioners, if these are dropped from a display stand or shelf to the floor while being displayed and sold in a store, the impact of the drop can cause the packaging case to crack along the creases, resulting in holes in the packaging case. In particular, when the plastic sheet is A-PET, the packaging case is easily prone to cracking due to the impact of the drop.

[0008] PP sheets are widely used for clear cases used to package heavy items because they are shatter-resistant even when dropped, but A-PET is less impact resistant than PP sheets, but it is highly transparent and can be collected and recycled as resource waste, so there is a great need for it to be used as an alternative material to PP. Furthermore, due to various environmentally conscious initiatives such as the recent SDGs, there is an increasing demand for plastic sheets made from environmentally friendly materials such as recycled PET and bio-PET, which are less impact resistant than A-PET.

[0009] In consideration of the problems with the conventional technology, the present invention aims to provide a plastic sheet with fold lines formed by adding fold lines to a plastic sheet with poor impact resistance such as A-PET, and to make it difficult for the packaging case to crack even if it is subjected to impact from being dropped when heavy items are stored in the packaging case and it is used for display and sale by folding the sheet along the fold lines. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a plastic sheet having multiple folding lines formed on only one surface side, the multiple folding lines defining a front panel, a back panel, left and right side panels, a glue tab, a lid portion that serves as a top lid, and a flap that serves as a bottom lid, the sheet being assembled into a box-shaped packaging case for packaging an item by folding the panels, the lid portion, and the flap along the folding lines, Each of the creases is a pressed crease formed by pressing a crease blade having a curved or flat cross section against the surface of the sheet, and each of the creases is provided such that an end of each of the creases does not reach an edge of the sheet, and an area between the end of each of the creases and the edge of the sheet is an uncreased area; The sheet surface on which the folding lines are formed is characterized in that it has a configuration in which a plurality of notches consisting of linear or band-shaped horizontal stripes that intersect with the folding lines are provided at predetermined intervals along each folding line.

[0011] According to this, a packaging case can be assembled by folding the sheet along the folding lines, and articles can be stored and packaged in this packaging case, which can then be displayed and sold. The fold lines formed on the surface of the sheet are non-through pressed lines formed by pressing a scoring blade with a curved or flat cross section against the surface of the sheet to stretch the surface of the sheet, and are less likely to develop holes or tear in the lines themselves compared to the rope pattern lines, lines formed by pressing a scoring blade with a sharp tip against the surface of the sheet, or perforated lines created by cutting the surface of the sheet. In addition, multiple notches are provided along the fold lines which are formed by the pressed creases, i.e., multiple horizontal notches are provided which intersect the vertical fold lines, so that when the sheet is folded, it is easy to raise the sheet along the fold lines and the sheet can be smoothly folded at right angles or acute angles along the fold lines.Furthermore, when a packaging case containing a heavy object is dropped and subjected to an impact, the impact force transmitted along the fold lines is dispersed by the multiple horizontal notches which intersect the fold lines.This, combined with the fact that the pressed lines themselves are not prone to holes or tears, makes it possible to effectively prevent the impact force from being concentrated on the fold lines and causing cracks in the packaging case along the fold lines.

[0012] As described above, it is preferable that the creases in the creased plastic sheet are arranged so that their ends do not reach the edges of the sheet, and that the area between the ends of the creases and the edges of the sheet is an uncreased area.

[0013] According to this, the creases are formed on the surface of the sheet with an unlined area between the ends of the creases and the edge of the sheet. In other words, the thickness of the edge of the sheet is the same all around, and there are no thinned areas where the creases intersect. Cracks that occur in the packaging case due to the impact of being dropped occur in areas where the sheet is thinner, such as areas where the creases are formed, and by providing an unlined area between the ends of the creases and the edge of the sheet as described above, it is possible to prevent the packaging case from cracking from its edge even if it is subjected to an impact of being dropped.

[0014] The plastic sheet is preferably an A-PET sheet, which is highly transparent and suitable for displaying and selling packaged items, and is being collected as resource waste after use and is being recycled. It is more preferable that the plastic sheet is made of an environmentally friendly material such as recycled PET or bio-PET. Instead of A-PET, the plastic sheet may be made of a single or composite plastic of biodegradable plastic such as PP or PLA, recycled PP, or other resin materials.

[0015] The plastic sheet is composed of a transparent or translucent sheet formed to a thickness of, for example, about 0.1 to 1 mm, preferably about 0.25 to 0.35 mm, more preferably about 0.3 mm, and has folding lines formed on its surface so that it can be assembled into a packaging case of a predetermined shape for packaging an article, and is punched out along the outer shape of the unfolded packaging case to form a plastic sheet with folding lines. If the plastic sheet is too thin, it is not possible to ensure the rigidity (shape retention) when assembled into a case, so the thickness is preferably 0.25 mm or more, and if the thickness is too large, it is difficult to assemble the case, so the thickness is preferably 0.35 mm or less.

[0016] The creases formed on the surface of the plastic sheet are press creases, which can be formed by pressing a single or multiple scoring blades against each folded portion of the plastic sheet with a pressure appropriate to the material, thickness, strength, hardness, etc. of the sheet. The scoring blades that form the creases can be ones with a rounded, curved, or flat or trapezoidal blade cross section as shown in Figure 3, and can be formed by pressing them against the sheet surface to stretch the sheet surface. 2, the width Wr of the folding rule can be set appropriately depending on the thickness of the sheet, etc. For example, when the thickness of the sheet is about 0.25 to 0.35 mm, the width Wr can be set to about 0.7 to 0.9 mm.

[0017] The indentations provided on the sheet surface along the creases are linear or band-like transverse lines formed by rubbing or cutting the sheet surface with a tool for processing the surface of a plastic sheet such as a grinder, wire discharge, punch, etc. A plurality of indentations are formed at predetermined intervals along the creases, intersecting the creases. 2, the width Wc of the notch and the arrangement interval D along the crease can be set appropriately depending on the thickness of the sheet, the width of the crease, etc. For example, when the sheet thickness is about 0.25 to 0.35 mm and the width of the crease is about 0.7 mm, the width Wc can be set to about 0.5 to 1 mm and the arrangement interval D to about 5 to 15 mm. The depth of the indentations is at least such that the pressed creases do not penetrate the sheet, and is preferably 1 / 10 or less of the sheet thickness. When the sheet thickness is about 0.25 to 0.35 mm, the depth of the indentations can be set to about 0.01 to 0.03 mm.

[0018] As described above, the fold lines on the surface of the plastic sheet are positioned so that their ends do not reach the edges of the sheet, i.e., so that the fold lines do not intersect with the edges of the sheet, and so that the area between the ends of the fold lines and the edges of the sheet is an unlined area. The distance between the end of the folding line and the edge of the sheet, that is, the width of the unlined region, can be appropriately set according to the thickness of the sheet and the dimensional ratio of the front of the packaging case assembled by folding the lined plastic sheet to its width (depth). If the width of the unlined region is large, the sheet is difficult to bend along the folding line, and the box-making properties are deteriorated, so the width of the unlined region is preferably 1 mm or more and 10 mm or less. For example, when the thickness of the sheet is about 0.25 to 0.35 mm, the vertical width Dv and horizontal width Dh of the unlined region can both be set to about 1.0 to 5 mm, as shown in FIG. 4. It is more preferable that the width of the unlined region is less than 3 mm.

[0019] The plastic sheet with creases having the above-described configuration can be manufactured, for example, through the steps of forming creases consisting of pressed creases on the surface of the plastic sheet, forming notches along the creases on the sheet surface, and punching out the plastic sheet to the outer shape of a packaging case. The sheet is folded along the folding lines on its surface to be assembled into a packaging case, and a commercial item is placed inside the case to form a package, which can then be displayed and sold at a storefront or the like. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a front view of a folded sheet having lined edges according to an embodiment of the present invention. [Diagram 2] 2 is a cutaway perspective view of a main part of the sheet, showing an enlarged view of folding lines formed on the sheet of FIG. 1. FIG. [Diagram 3] 2A to 2C are diagrams illustrating examples of cross sections of the tip of a scoring blade used to form folding creases in the sheet of FIG. 1. [Figure 4] FIG. 2 is an enlarged view of part A in FIG. [Diagram 5] 2 is an external view of a packaging case formed by assembling the sheets of FIG. 1 and containing an article. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A preferred embodiment of the present invention will now be described with reference to the drawings. It should be noted that the following embodiments are merely examples for explaining the present invention, and the present invention is not limited to the embodiments.

[0022] FIG. 1 shows the surface of a folded lined sheet according to one embodiment of the present invention. This sheet 1 is made of a transparent plastic sheet, and folding lines 2 formed on its surface define a front panel 11, a back panel 12, and left and right side panels 13, 14, each of which has a rectangular plate surface, cover panels 16 connected to the upper edges of the front panel 11 and back panel 12, flaps 17 connected to the lower edges of the front panel 11 and back panel 12 and the upper and lower edges of the left and right side panels 13, 14, respectively, and a glue tab 15 connected to the side edge of the front panel 11. By folding each part along the folding lines 2, it can be assembled into a packaging case for storing item M, as shown in Figure 5.

[0023] FIG. 2 shows a folding line 2 formed on the surface of a sheet 1. The folding line 2 is formed by pressing a scoring blade with a curved cutting edge as shown in FIG. 3(A) against the sheet surface to form a non-through pressed score, thereby stretching the sheet surface. In addition, on the surface of the sheet 1 on which the folding lines 2 are formed, a plurality of notches 3 intersecting the folding lines 2 are provided at predetermined intervals along the folding lines 2 over the entirety of the folding lines 2.

[0024] Also, as shown in FIG. 4, the fold line 2 is positioned so that its end does not reach the edge of the sheet 1, i.e., so that the fold line 2 does not intersect with the edge of the sheet 1, and the area between the end of the fold line 2 and the edge of the sheet 1 is an unlined area. EXAMPLES

[0025] The resistance to cracking of the packaging kale assembled by folding the score-lined plastic sheet of the above embodiment was verified in the following examples.

[0026] Example 1 A sheet 1 shown in FIG. 1 was produced using A-PET (Novaclear (registered trademark) A-3020: manufactured by Mitsubishi Chemical Corporation) having a thickness of 0.3 mm. The size of the sheet 1 in Figure 1 is such that each panel has a height H of 192 mm, a width W of 140 mm, and a width (T) of 62 mm for each of the left and right side panels. A scoring blade with a curved cutting edge cross section as shown in Figure 3(A) was pressed against the surface to form a plurality of pressed creases 2 with a width Wr of 0.7 mm in both the vertical and horizontal directions to divide each panel. Each fold line 2 was formed so as to leave an unformed area of ​​width 2 mm between its end and the edge of the sheet 1 . In addition, multiple notches 3 each having a width of 0.9 mm were formed along each of the creases 2 so as to intersect with each other, with notches spaced 10.0 mm apart.

[0027] The sheet 1 was folded along each folding line 2, and the adhesive portion 15 was glued and fixed to the outside of the side panel 14 to form a tube. Each of the flaps was folded inward to assemble the packaging case shown in Figure 5, and an item M (decorative sheet) weighing 696g, equivalent to a product for customers, was stored and packaged in this case.

[0028] A test was conducted in which a case containing the item M was dropped from a height of 100 cm from the floor surface onto a floor made of plastic tiles to verify whether the case would crack. The drop was performed five times (n=5) with the front panel 11 of the case (sheet 1) facing downwards, and with the corners of the front panel 11 and side panel 13 facing downwards. The results are shown in Table 1. In the table, the drop is marked with "O" if no cracks occurred, and marked with "X" if cracks occurred.

[0029] Example 2 The same test was carried out using the same case 1 as in Example 1, except that the width of the notches 3 was 1.0 mm and the notch interval was 5.0 mm. The results are shown in Table 1.

[0030] Example 3 The same test was carried out using the same case 1 as in Example 1, except that the width of the notches 3 was 1.0 mm and the notch interval was 15.0 mm. The results are shown in Table 1.

[0031] Example 4 A similar test was carried out using the same case 1 as in Example 1, except that the width of the notches 3 was 1.0 mm and the notch interval was 5.0 mm, and the drop height was set to 150 cm. The results are shown in Table 1.

[0032] Example 5 A similar test was carried out using the same case 1 as in Example 1, except that the width of the notches 3 was 1.0 mm and the notch interval was 15.0 mm, and the drop height was set to 150 cm. The results are shown in Table 1.

[0033] Comparative Example 1 A similar test was carried out using a PP sheet (High P Crystal (registered trademark) ST-700: manufactured by Tatsuta Chemical Co., Ltd.) having a thickness of 0.3 mm, and using the same case 1 as in Example 1, except that no notches were made and no areas where creases were not formed were made. The results are shown in Table 2.

[0034] Comparative Example 2 The same test was carried out using the same case 1 as in Example 1, with the drop height set to 80 cm, except that the width of the notches 3 was 0.3 mm, the notches were spaced 5 mm apart, there were no unformed areas of the fold lines 2, and both ends of each fold line 2 reached the edges of the sheet 1. The results are shown in Table 2.

[0035] Comparative Example 3 The same test was carried out using the same case 1 as in Example 1, except that the width of the notches 3 was 0.9 mm, the notches were spaced 5 mm apart, there were no unformed areas of the folding lines 2, and both ends of each folding line 2 reached the edges of the sheet 1. The results are shown in Table 2.

[0036] -Verification of use in cold climates Example 6 The same case 1 as in Example 1 was used, except that the width of the notches 3 was 1.0 mm and the notch interval was 5.0 mm. This was stored in a refrigerator (refrigerating temperature 5°C) for 2 hours, and then removed from the refrigerator and subjected to the same test. The drop test was performed only with the front panel of the case facing downward. The results are shown in Table 1.

[0037] Example 7 A test was carried out in the same manner as in Example 6 using Case 1 similar to that in Example 1, except that the width of the notches 3 was 1.0 mm and the notch interval was 10.0 mm. The results are shown in Table 1.

[0038] Example 8 The same case 1 as in Example 1 was used, except that the width of the notches 3 was 1.0 mm and the notch interval was 15.0 mm, and after storing in a refrigerator in the same manner as in Example 6, a similar test was performed with the drop height set to 150 cm. The results are shown in Table 1.

[0039] Comparative Example 4 The same case 1 as in Example 1 was used, except that the width of the notches 3 was 1.0 mm, the notches were spaced 5 mm apart, there were no unformed areas of the creases 2, and both ends of each crease 2 reached the edge of the sheet 1. The same test was performed after storing the case 1 in a refrigerator and then removing it from the refrigerator in the same manner as in Example 6. The drop height for the drop test was set to 150 cm. The results are shown in Table 2.

[0040] -Verification of use in extremely cold regions Example 9 The same case 1 as in Example 1 was used except that the width of the notches 3 was 1.0 mm and the notch interval was 5.0 mm, and this was immersed in ice water (0 to 1° C.) for 30 minutes, then removed and subjected to the same test as in Example 6. The results are shown in Table 1.

[0041] Example 10 Except for changing the width of the notches 3 to 1.0 mm and the notch interval to 10.0 mm, the same case 1 as in Example 1 was used, and immersion in ice water and testing were carried out in the same manner as in Example 9. The results are shown in Table 1.

[0042] Example 11 Except for the width of the notches 3 being 1.0 mm and the notch interval being 15.0 mm, the same case 1 as in Example 1 was used, and immersion in ice water and testing were carried out in the same manner as in Example 9. The results are shown in Table 1.

[0043] Comparative Example 5 The same case 1 as in Example 1 was used, except that the width of the notches 3 was 1.0 mm, the notches were spaced 5 mm apart, there were no unformed areas of the folding lines 2, and both ends of each folding line 2 reached the edges of the sheet 1. The same test was carried out after immersing the case in ice water in the same manner as in Example 9. The results are shown in Table 2.

[0044] The comparative example 1 is a so-called conventional case made of a PP sheet, and since the impact resistance of the sheet is better than that of the A-PET sheets of the comparative examples 2 and 3, the case is less likely to crack when it is subjected to impact after being assembled and packaging an article. The case of the present invention is made such that even if the case uses a sheet with lower impact resistance than the PP sheet, it is less likely to crack when it is subjected to impact due to being dropped. The cases of the comparative examples other than Comparative Example 1 and the examples are all similar in that they use 0.3 mm thick A-PET, have a 0.7 mm wide fold line consisting of a non-penetrating pressed line formed on the surface of the sheet, and have multiple notches formed horizontally along this fold line and intersecting with the fold line, but the width and spacing of the notches differ in each example. Also, each example and Comparative Examples 2 and 3 differ in configuration in that, while each example is formed so that an unformed area of ​​an appropriate width is secured between the end of each fold line and the edge of the sheet, Comparative Examples 2 and 3 have no unformed area and have a continuous fold line extending between the opposing ends of the sheet.

[0045] According to the test results of Comparative Examples 2 and 3, no cracks were generated when the case was dropped with its front side facing down, but cracks were generated when the case was dropped multiple times with a corner facing down. In contrast, according to the test results of Examples 1 to 5, no cracks were generated whether the case was dropped with its front side or a corner facing down, and it was confirmed that the presence of unformed areas at the ends of the creases makes it difficult for cracks to be generated at the edges of the creases due to the impact of the drop.

[0046] Examples 6 to 8 and Comparative Example 4, and Examples 9 to 11 and Comparative Example 5 were evaluated for cracking of the case in a low temperature environment. In Comparative Example 4, cracking occurred after four drop tests, and in Comparative Example 5, cracking occurred after one drop test. On the other hand, the test results of Examples 6 to 11 confirmed that they were more susceptible to cracking when dropped than the cases of Examples 1 to 5, which were evaluated under room temperature conditions. Also, it was confirmed that cracking was least likely to occur when the interval between the notches along the fold lines was set to 15 mm. In addition, the workability (ease of assembly) when assembling the cases of each of the above-mentioned examples into a box was better in the cases with a notch width of 10 mm or 15 mm than in the case with a width of 5 mm.

[0047] [Table 1]

[0048] [Table 2]

[0049] -Verification of changes in the depth of the notch Example 12 The same test was carried out using the same case 1 as in Example 1, except that the width of the notch 3 was 1.0 mm, the depth of the notch was 0.01 mm, and the notch interval was 5.0 mm. The results are shown in Table 3.

[0050] (Example 13) The same test was carried out using the same case 1 as in Example 12, except that the depth of the notch was 0.03 mm. The results are shown in Table 3.

[0051] Example 14 The same test was carried out using Case 1 as in Example 12, except that the depth of the notches was 0.02 mm and the notch interval was 10 mm. The results are shown in Table 3.

[0052] Example 15 The same test was carried out using the same case 1 as in Example 14, except that the depth of the notch was 0.03 mm. The results are shown in Table 3.

[0053] (Example 16) The same test was carried out using Case 1 as in Example 12, except that the depth of the notches was 0.03 mm and the notch interval was 15 mm. The results are shown in Table 3.

[0054] (Example 17) A similar test was carried out using Case 1 of Example 16, but with the drop height set to 150 cm. The results are shown in Table 3.

[0055] Comparative Example 6 The same test was carried out using the same case 1 as in Example 1, except that the width of the notch 3 was 1.0 mm, the depth of the notch was 0.07 mm, and the notch interval was 5.0 mm. The results are shown in Table 4.

[0056] Comparative Example 7 Except for changing the pitch interval to 10.0 mm, the same test was carried out using Case 1 as in Comparative Example 5. The results are shown in Table 4.

[0057] Comparative Example 8 Except for changing the pitch interval to 15.0 mm, the same test was carried out using Case 1 as in Comparative Example 5. The results are shown in Table 4.

[0058] Comparative Example 9 A similar test was carried out using the same case 1 as in Comparative Example 7, except that the depth of the notch 3 was 0.1 mm. The results are shown in Table 4.

[0059] According to the test results of Examples 12 to 15, it was confirmed that if the depth of the notch was 1 / 10 or less of the thickness of the sheet (0.3 mm), the case would not crack even after being dropped four times in both drop tests with the front side facing down and with a corner facing down. On the other hand, according to the test results of Comparative Example 6 to Comparative Example 9, it was confirmed that the deeper the notch, the easier it was for the case to crack. This is thought to be because when the sheet is folded, the deep notch makes the part along the fold line too thin, making it easier for cracks to occur. It is considered appropriate to set the depth of the notch in the range of Examples 12 to 15. Furthermore, according to the test results of Examples 12 to 17, in Example 17, in which the spacing between the notches was 15 mm, no cracks occurred in the case during the drop test, and it was confirmed that a somewhat larger spacing (15 mm) than a narrower spacing (5 mm) provides a better shock absorption effect when the case is dropped.

[0060] [Table 3]

[0061] [Table 4]

[0062] It should be noted that the illustrated shape of the folded sheet with the lines is merely an example, and the present invention can be configured in other suitable shapes. [Explanation of symbols]

[0063] 1 Plastic sheet with creases (sheet, case), 2 creases, 3 notches, M item

Claims

1. A plastic sheet having a plurality of folding lines formed on only one surface side, the folding lines defining a front panel, a back panel, left and right side panels, a glue tab, a lid section which serves as a top lid, and a flap which serves as a bottom lid, the folding lines being assembled into a box-shaped packaging case for packaging an article by folding the panels, the lid section, and the flap along the folding lines, Each of the creases is a pressed crease formed by pressing a crease blade having a curved or flat cross section against the surface of the sheet, and each of the creases is provided such that an end of each of the creases does not reach an edge of the sheet, and an area between the end of each of the creases and the edge of the sheet is an uncreased area; A plastic sheet with creases, characterized in that the sheet surface on which the creases are formed has a configuration in which a plurality of notches consisting of linear or band-like horizontal stripes that intersect with the creases are provided at predetermined intervals along each crease.

2. The score-lined plastic sheet according to claim 1 is assembled into a box-shaped packaging case having a surface of a plastic sheet having a thickness of 0.25 to 0.35 mm and a plurality of score lines each having a width of 0.7 mm formed thereon, The score lines are formed in a plastic sheet having a width of 0.5 to 1 mm, an interval of 5 to 15 mm, and a depth of 0.01 to 0.03 mm.

3. 3. The creased plastic sheet according to claim 2, which is made of a plastic sheet having a thickness of 0.3 mm.

4. 4. The plastic sheet with folding lines according to claim 1, 2 or 3, wherein the notches have a width of 1 mm, are spaced apart from each other by 15 mm, and have a depth of 0.03 mm.

5. 4. The creased plastic sheet according to claim 1, 2 or 3, wherein the plastic sheet is an A-PET sheet or a PP sheet.

6. 4. The creased plastic sheet according to claim 1, 2 or 3, wherein the plastic sheet is made of recycled PET, recycled PP, bio-PET or a biodegradable plastic.

7. 4. A packaging case which is assembled by folding the score-lined plastic sheet according to claim 1, 2 or 3 along the score lines provided on the surface of the sheet.

8. A package comprising an article housed in the packaging case according to claim 7.

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