Drainage bowl cover and preparation method thereof

Abstract

The invention discloses a drainage bowl cover and a preparation method thereof, and relates to the technical field of food packaging. The drainage bowl cover comprises a bowl cover body, wherein the bowl cover body comprises an upper cover, a release layer and a lower cover which are arranged in sequence; the bowl cover body further comprises a first tongue piece and a second tongue piece which protrude outwards. The upper cover is provided with a first knife line, the first knife line penetrates through the upper cover, and the first knife line and the first tongue piece are enclosed to form a peelable piece; a second knife line is arranged between the first knife line and the first tongue piece, and the second knife line penetrates through the lower cover in a cutting manner; a third knife line is arranged on the lower cover, and the third knife line penetrates through the lower cover in a cutting manner to form a plurality of drainage hole films; a plurality of micropores are formed in the release layer, and the release layer is also provided with a through hole corresponding to the drain hole film. The drainage function of the bowl cover is achieved by arranging the peelable piece, and the uncovering force of the peelable piece can be more controllable on the basis that the coating amount of the release agent is not changed through the micropores formed in the peelable piece.

Description

Technical Field

[0001] The present invention relates to the technical field of food packaging, and particularly to a drainage bowl cover and a preparation method thereof. Background Art

[0002] In the technical field of food packaging, especially for the packaging of bowl-shaped foods, in order to achieve the drainage function and facilitate consumers to open, the design of the bowl cover is crucial. The structure of the currently used water-filtering bowl cover is as shown in Chinese Patent CN100497124C. This technology uses the method of printing a release agent on paper. However, this design has many defects: on the one hand, the paper itself has a porous structure and has an absorption effect on the release agent, making it difficult for the release agent to be evenly distributed on the paper surface and effectively play its role, resulting in poor release effect. To make up for this deficiency, it is necessary to increase the coating amount of the release agent, which not only increases the production cost but also may introduce more solvent residue risks. On the other hand, when consumers use such bowl covers, for example, when soaking instant noodles, the high-temperature water vapor will wet the paper layer through the water-filtering part provided on the lower cover. The paper has strong water absorption. After being wetted by the high-temperature water vapor, its physical properties change, the strength decreases, and the adhesion degree between the paper and the lower cover increases, resulting in difficulty in peeling off the drainage part, bringing a very poor user experience to consumers and unable to meet the requirements of convenient and efficient opening of the packaging. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a drainage bowl cover and a preparation method thereof.

[0004] Specifically, it includes the following technical solutions:

[0005] In a first aspect, a drainage bowl cover is provided, which includes a bowl cover body. The bowl cover body includes an upper cover, a release layer, and a lower cover arranged in sequence; the bowl cover body further includes a first tongue and a second tongue protruding outward; the upper cover is provided with a first score line that cuts through the upper cover, and the first score line and the first tongue enclose a peelable sheet; a second score line is provided between the first score line and the first tongue, and the second score line cuts through the lower cover; the lower cover is provided with a third score line that cuts through the lower cover to form a plurality of drainage hole membranes; a plurality of micropores are provided in the release layer, and the release layer is further provided with through holes corresponding to the drainage hole membranes; the upper cover includes a protective layer, an ink layer, and a printing film layer arranged from top to bottom in sequence, the lower cover includes an adhesive layer, a barrier layer, and a heat-sealing layer arranged from top to bottom in sequence, and the release layer is arranged between the printing film layer and the adhesive layer;

[0006] The printing film layer is a PP synthetic paper (PP: polypropylene) or composed of a PP synthetic paper and PET (PET: polyethylene terephthalate). Preferably, the outer contour of the drainage bowl cover is similar to the outer contour of the container with which it is used in a matching manner, and both the first tongue and the second tongue protrude from the shape of the container body.

[0007] Preferably, the first cutting line divides the upper cover into an upper cover body and a peelable sheet.

[0008] Preferably, the first tongue piece and the second tongue piece are respectively arranged at opposite ends of the bowl cover body.

[0009] Preferably, the second knife line is arranged at the connection between the first knife line and the first tongue piece.

[0010] Preferably, the release layer is arranged on both sides of the second knife line.

[0011] Preferably, the release layer is arranged below the first tongue piece, except for the end of the first tongue piece.

[0012] The second cutting line is arranged so that a handle is formed on the first tongue piece for consumers to peel off the peelable piece.

[0013] Preferably, the drainage hole membrane formed by the third knife line is tangentially closed.

[0014] Furthermore, the components of the PP synthetic paper include polypropylene resin, inorganic filler and non-fluorescent physical brightener; the inorganic filler is calcium carbonate, and the weight percentage of the inorganic filler in the PP synthetic paper is 20-40%; the non-fluorescent physical brightener is titanium dioxide, and the weight percentage of the non-fluorescent physical brightener in the PP synthetic paper is 1-5%.

[0015] Furthermore, the whiteness of the PP synthetic paper is ≥70%, and the surface tension of both sides of the PP synthetic paper is ≥38 dynes.

[0016] Preferably, both sides of the PP synthetic paper are corona treated.

[0017] Furthermore, the density of the PP synthetic paper is 0.6-0.95 g / cm 3 , thickness is 30-100μm.

[0018] Furthermore, the diameter of the micropores is 0.1-1.0 mm.

[0019] Furthermore, the release layer includes one or more of nitrocellulose resin and wax.

[0020] Among them, the release layer can effectively reduce the adhesion of the adhesive layer to the upper and lower parts and reduce the interlayer peeling force.

[0021] Furthermore, the protective layer is varnish or PET.

[0022] Further, the adhesive layer includes one or more of polyurethane adhesives and polyethylene resins; the barrier layer is at least one of a composite film of PET and aluminum foil, aluminum foil, aluminized PET, and aluminized OPP (OPP: o-phenylphenol).

[0023] Further, the heat-sealing layer is selected from one or more of polyurethane adhesives, extrusion coating resins, and cast PE films (PE: polyethylene).

[0024] Preferably, the extrusion coating resin is one or more of LDPE resin (LDPE: low-density polyethylene), EMA resin (EMA: ethylene-methyl acrylate copolymer), EMAA resin (EMAA: ethylene-methyl methacrylate copolymer), EVA resin (EVA: ethylene-vinyl acetate copolymer), and PE resin.

[0025] Second, a method for preparing the drainage bowl cover as described in the first aspect is provided, including the following steps:

[0026] S1. After preparing the printed film layer, use a printing press to print an ink layer on one side of the printed film layer and a release layer on the other side of the printed film layer to obtain the first laminate.

[0027] S2. Use a printing press or a dry laminator to prepare a protective layer on the side of the ink layer of the first laminate to obtain the upper cover.

[0028] S3. Use an extrusion coater to extrude coat the adhesive layer on the side of the release layer, and laminate the barrier layer on the adhesive layer to form the second laminate.

[0029] S4. Use an extrusion coater or a dry laminator to prepare a heat-sealing layer on the side of the barrier layer of the second laminate to obtain a semi-finished bowl cover roll film.

[0030] S5. Subject the semi-finished bowl cover roll film to semi-die cutting of the upper cover, semi-die cutting of the lower cover, and die cutting of the outer contour to obtain the drainage bowl cover.

[0031] Preferably, in step S1, when the printed film layer is PP synthetic paper, step S1 is to directly use the PP synthetic paper to prepare the printed film layer.

[0032] Preferably, in step S1, when the printed film layer is composed of PP synthetic paper and PET, step S1 is to use a dry laminator to laminate the PP synthetic paper and PET together to prepare the printed film layer.

[0033] Preferably, in step S2, when the printed film layer is PP synthetic paper, step S2 is to use a printing press to prepare a protective layer (varnish) on the side of the ink layer of the first laminate.

[0034] Preferably, in step S2, when the printing film layer is composed of PP synthetic paper and PET, step S2 is to use a dry laminator to laminate one side of the ink layer of the first laminate with the protective layer (PET).

[0035] Preferably, in step S4, when preparing the heat-sealing layer, when PE resin is selected as the heat-sealing layer, the extrusion coating thickness of the PE resin is ≥ 15 μm.

[0036] Compared with the prior art, the present invention provides a drainage bowl cover and its preparation method, having the following beneficial effects:

[0037] The present invention realizes the drainage function of the bowl cover by setting a peelable sheet. The micropores provided at the peelable sheet can make the peeling force of the peelable sheet more controllable without changing the coating amount of the release agent; using PP synthetic paper instead of paper to prepare the bowl cover reduces the usage amount of the release agent and avoids the risk of solvent residue. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 Schematic diagram of peeling off the peelable sheet of the drainage bowl cover in Embodiment 1 of the present invention;

[0040] Figure 2 Schematic diagram of the upper cover structure of the drainage bowl cover in Embodiment 1 of the present invention;

[0041] Figure 3 Schematic diagram of the lower cover structure of the drainage bowl cover in Embodiment 1 of the present invention;

[0042] Figure 4 Schematic diagram of the overall structure of the drainage bowl cover in Embodiment 1 of the present invention;

[0043] Figure 5 Top view of the drainage bowl cover in Embodiment 1 of the present invention;

[0044] Figure 6 Bottom view of the drainage bowl cover in Embodiment 1 of the present invention;

[0045] Figure 7 Bottom view of the peelable sheet of the drainage bowl cover in Embodiment 1 of the present invention;

[0046] Figure 8 is Figure 7 cross-sectional view along the A-A direction in;

[0047] Figure 9It is an enlarged view of the second score line of the drainage bowl cover in Embodiment 1 of the present invention;

[0048] Figure 10 It is an enlarged view of the micropores of the drainage bowl cover in Embodiment 1 of the present invention;

[0049] Explanation of the markings in the figure:

[0050] 1 - Release layer; 2 - First tongue; 3 - Second tongue; 4 - First score line; 5 - Peelable sheet; 6 - Second score line; 7 - Third score line; 8 - Drainage hole membrane; 9 - Micropores; 10 - Protective layer; 11 - Ink layer; 12 - Printed film layer; 13 - Adhesive layer; 14 - Barrier layer; 15 - Heat-sealing layer; d - Offset distance. Detailed implementation manners

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0053] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in this specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0054] It should be further understood that the term " / and / " used in this specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0055] To more fully understand the technical content of the present invention, the technical solutions of the present invention will be further introduced and described below with reference to specific embodiments.

[0056] Embodiment 1

[0057] Please refer to Figures 1 - 10A drainage bowl cover shown in the figure includes a bowl cover body, wherein the bowl cover body includes an upper cover, a release layer 1 and a lower cover arranged in sequence; the bowl cover body also includes a first tongue piece 2 and a second tongue piece 3 protruding outward; in this embodiment, the first tongue piece 2 and the second tongue piece 3 are respectively arranged at opposite ends of the bowl cover body. The upper cover is provided with a first knife line 4, the first knife line 4 cuts through the upper cover, and the first knife line 4 and the first tongue piece 2 are enclosed to form a peelable sheet 5; the first knife line 4 divides the upper cover into an upper cover body and a peelable sheet 5. A second knife line 6 is provided between the first knife line 4 and the first tongue piece 2, and the second knife line 6 cuts through the lower cover; in this embodiment, the release layer 1 is arranged on both sides of the second knife line 6. The arrangement of the second knife line 6 forms a handle portion on the first tongue piece 2 for consumers to uncover the peelable sheet 5.

[0058] The lower cover is provided with a third knife line 7, which cuts through the lower cover to form a plurality of drainage hole membranes 8; the drainage hole membranes 8 formed by the third knife line 7 are tangentially closed. The release layer 1 is provided with a plurality of micropores 9, and the release layer 1 is also provided with through holes corresponding to the drainage hole membranes 8. In this embodiment, the micropores 9 are circular, with a diameter of 0.35 mm and a distribution density of 1.47 pores / mm 2 , the offset distance d is 4mm.

[0059] The upper cover includes a protective layer 10, an ink layer 11, and a printed film layer 12 arranged in sequence from top to bottom, and the lower cover includes an adhesive layer 13, a barrier layer 14, and a heat-sealing layer 15 arranged in sequence from top to bottom, and the release layer 1 is arranged between the printed film layer 12 and the adhesive layer 13. The protective layer 10 is PET, and the printed film layer 12 is composed of PP synthetic paper and PET. The adhesive layer 13 is polyethylene resin, the barrier layer 14 is a composite film of PET and aluminum foil, and the heat-sealing layer 15 is composed of LDPE resin and polyethylene resin (PE resin). The release layer 1 is composed of nitrocellulose resin and wax. In this embodiment, the components of the PP synthetic paper include polypropylene resin, inorganic filler and non-fluorescent physical brightener; the inorganic filler is calcium carbonate, and the inorganic filler accounts for 30% by weight of the PP synthetic paper; the non-fluorescent physical brightener is titanium dioxide, and the non-fluorescent physical brightener accounts for 3% by weight of the PP synthetic paper. The whiteness of the PP synthetic paper is 70%, both sides of the PP synthetic paper are corona treated, and the surface tension of both sides of the PP synthetic paper is 38 dynes.

[0060] Since the release layer 1 is provided with through holes corresponding to the drainage hole membrane 8, that is, the release layer 1 is not coated between the drainage hole membrane 8 and the upper cover, this means that the adhesive layer 13 of the lower cover will still function normally, making it difficult for the drainage hole membrane 8 to be peeled off from the upper cover. When the consumer grasps the first tongue piece 2 to peel off the peelable sheet 5, the drainage hole membrane 8 with a tangent line closed will adhere to the peelable sheet 5, so that the lower cover forms several drainage holes with the same shape as the drainage hole membrane 8, thereby realizing the drainage function of the drainage bowl cover.

[0061] The method for preparing the drainage bowl cover comprises the following steps:

[0062] S1. Use a dry laminating machine to make PP synthetic paper (thickness 45μm, density 0.9g / cm 3 ) and PET (thickness of 19 μm) are compounded together to prepare a printed film layer 12, and an ink layer 11 is printed on the PET side of the printed film layer 12, and a release layer 1 is printed on the PP synthetic paper side of the printed film layer 12 by a printing machine to obtain a first laminate;

[0063] S2. Using a dry laminating machine, the ink layer 11 on one side of the first laminate is compounded with the protective layer 10 (PET, thickness of 19 μm) to obtain a cover;

[0064] S3. A laminating machine is used to laminar an adhesive layer 13 (polyethylene resin, specifically LDPE resin, produced by Hanwha, South Korea, with a laminating thickness of 20 μm) on one side of the release layer 1, and a barrier layer 14 (a composite film of PET with a thickness of 12 μm and an aluminum foil with a thickness of 7 μm) is laminated on the adhesive layer 13 to form a second laminate;

[0065] S4. Using a laminating machine, a heat-sealing layer 15 is prepared on one side of the barrier layer 14 of the second laminate to obtain a semi-finished bowl cover roll film; wherein, the specific steps of preparing the heat-sealing layer 15 are: laminating one side of the barrier layer 14 with a mixed resin (the mixed resin uses LDPE resin produced by Hanwha of South Korea and LDPE resin produced by INEOS, the weight ratio of the resin is Hanwha LDPE: INEOS LDPE = 6:1, and the laminating thickness is 20 μm), and then laminating with a polyethylene resin (using a modified easy-to-release PE resin produced by Tosoh of Japan, and the laminating thickness is 20 μm);

[0066] S5. The bowl cover roll film semi-finished product is subjected to upper cover half die-cutting, lower cover half die-cutting, and outer contour die-cutting to obtain a drainage bowl cover.

[0067] Example 2

[0068] The difference between Example 2 and Example 1 is that the density of the PP synthetic paper in Example 2 is 0.8 g / cm 3 , the other conditions are the same.

[0069] Example 3

[0070] Example 3 is different from Example 1 in that the density of the PP synthetic paper in Example 3 is 0.7 g / cm 3 , and the other conditions are the same.

[0071] Example 4

[0072] Example 4 is different from Example 1 in that the protective layer in Example 4 is varnish, and the other conditions are the same.

[0073] Example 5

[0074] Example 5 is different from Example 1 in that the heat-sealing layer in Example 5 is a cast PE film, and step S4 in the preparation method of Example 5 is to use a dry laminator to prepare a heat-sealing layer on one side of the barrier layer of the second laminate to obtain a semi-finished bowl lid roll film; wherein, the specific steps for preparing the heat-sealing layer are: laminating one side of the barrier layer with a cast PE film (thickness of 60 μm) together, and the other conditions are the same.

[0075] Example 6

[0076] Example 6 is different from Example 1 in that the printing film layer in Example 6 is PP synthetic paper, and step S1 in the preparation method of Example 6 is to directly use PP synthetic paper to prepare the printing film layer, and then use a printing machine to print an ink layer on one side of the printing film layer and a release layer on the other side of the printing film layer to obtain the first laminate, and the other conditions are the same.

[0077] Example 7

[0078] Example 7 is different from Example 1 in that the diameter of the micropores in the release layer in Example 7 is 0.15 mm, and the other conditions are the same.

[0079] Example 8

[0080] Example 8 is different from Example 1 in that the diameter of the micropores in the release layer in Example 8 is 0.25 mm, and the other conditions are the same.

[0081] Example 9

[0082] Example 9 is different from Example 1 in that the diameter of the micropores in the release layer in Example 9 is 0.45 mm, and the other conditions are the same.

[0083] Example 10

[0084] Example 10 is different from Example 1 in that the diameter of the micropores in the release layer in Example 10 is 0.55 mm, and the other conditions are the same.

[0085] Example 11

[0086] Example 11 is different from Example 1 in that in step S4 of the preparation method of Example 11, the coating thickness of the polyethylene resin is 18 μm, and the other conditions are the same.

[0087] Example 12

[0088] Example 12 is different from Example 1 in that in step S4 of the preparation method of Example 12, the coating thickness of the polyethylene resin is 15 μm, and the other conditions are the same.

[0089] Example 13

[0090] Example 13 is different from Example 1 in that in step S4 of the preparation method of Example 13, the coating thickness of the polyethylene resin is 12 μm, and the other conditions are the same.

[0091] I. Self-sealing temperature and appearance evaluation test:

[0092] 1) Preparation of test samples

[0093] (1) Pretreatment: Take Examples 1 - 5 for pretreatment (Pretreatment: Equilibrate for 24 hours in an environment with a temperature of 23 ± 2°C and a humidity of 50 ± 5% RH);

[0094] (2) Cutting specifications: Cut the test samples into strip-shaped specimens with a width of 15 mm and a length of 150 mm.

[0095] 2) Setting of heat-sealing process parameters

[0096] Use a heat-sealer to complete the heat-sealing of the strip-shaped specimens with the following heat-sealing parameters: Heat-sealing pressure: 360 N, heat-sealing time: 1.0 s, initial heat-sealing temperature: 150°C.

[0097] 3) Self-sealing temperature test

[0098] (1) Use a universal tensile testing machine and set the tensile speed to 300 mm / min;

[0099] (2) Stretch the heat-sealed specimen vertically along the heat-sealing line, start heat-sealing at 150°C at intervals of 5°C until the critical temperature at which the heat-sealing strength ≥ 6 N is reached, and record the temperature at this time.

[0100] 4) Appearance evaluation

[0101] (1) Visual inspection: Observe the surface flatness of the heat-sealed part under a standard light source;

[0102] (3) Judgment criteria: Classify according to the severity of the orange peel phenomenon: Grade 0 (none), Grade 1 (slight wrinkles), Grade 2 (severe wrinkles).

[0103] The self-sealing temperature and appearance evaluation tests were carried out on the drainage bowl lids of Examples 1-5, and the test results are shown in Table 1 below:

[0104] Table 1 Self-sealing temperature and appearance evaluation test results of the drainage bowl lids of Examples 1-5

[0105] Example Critical temperature Thermal seal flatness Example 1 175℃ Level 0 Example 2 175℃ Level 1 Example 3 175℃ Level 2 Example 4 180℃ Level 0 Example 5 175℃ Level 0

[0106] From the test results in Table 1, it can be seen that the drainage bowl lids of the embodiments of the present invention have a relatively high heat-sealing temperature and good heat-sealing flatness.

[0107] II. Peelable sheet lid-lifting test:

[0108] 1) Pretreatment

[0109] (1) Pretreatment: Take Examples 1 and 7-10 for pretreatment (pretreatment: balance for 24 hours in an environment with a temperature of 23±2°C and a humidity of 50±5%RH);

[0110] 2) Peelable sheet lid-lifting test

[0111] (1) Test method: Use a lid-lifting force tester. Clamp the first tongue of the sample with the upper chuck and start the lid-lifting test, and record the force value of the initial lid-lifting force;

[0112] (2) Judgment criterion: Classify according to the size of the initial lid-lifting force: Grade 0 (initial lid-lifting force ≤ 0.5 N), Grade 1 (0.5 N < initial lid-lifting force ≤ 1.5 N), Grade 2 (initial lid-lifting force > 1.5 N);

[0113] The peelable sheet lid-lifting tests were carried out on the drainage bowl lids of Examples 1 and 7-10, and the test results are shown in Table 2 below:

[0114] Table 2 Peelable sheet lid-lifting test results of the drainage bowl lids of Examples 1 and 7-10

[0115] Example Initial lid-opening force Microporous pattern setting parameters Example 1 Level 1 <![CDATA[Circular, 0.35 mm, 1.47 per mm 2 , offset distance 4 mm]]> Example 7 Level 0 <![CDATA[Round, 0.15 mm, 1.47 per mm 2 , offset distance 4 mm]]> Example 8 Level 1 <![CDATA[Circular, 0.25 mm, 1.47 per mm 2 , offset distance 4 mm]]> Example 9 Level 1 <![CDATA[Round, 0.45 mm, 1.47 per mm 2 , offset distance 4 mm]]> Example 10 Level 2 <![CDATA[Circular, 0.55 mm, 1.47 per mm 2 , offset distance 4 mm]]>

[0116] From the test results in Table 2, it can be seen that for the drainage bowl lids of the embodiments of the present invention, as the diameter of the micropores of the release layer increases, the initial lid-lifting force gradually increases.

[0117] III. Ease of lid removal test:

[0118] 1) Preparation of test samples

[0119] Take a bucket-type instant noodle bowl with an inner layer laminated with PE resin, put the noodle cake into it, and use a capping machine to seal the above embodiments with the bucket-type instant noodle bowl containing the noodle cake (heat-sealing parameters: 190-200°C / 1 s / 0.4 MPa),

[0120] 2) Sample preparation for lid removal

[0121] After waiting for the heat-sealed area of the bowl lid to cool down, grasp the side of the bowl lid away from the sub-lid and pull the tongue part to remove the bowl lid, and evaluate it according to the following evaluation criteria.

[0122] NG: There is a large resistance when removing the lid, and it is difficult to remove.

[0123] OK: The lid removal is relatively smooth and easy to remove.

[0124] Perform the lid removal ease test on the drainage bowl lids of Example 1, Example 5, and Examples 11-13. The test results are shown in Table 3 below:

[0125] Table 3 Test results of the lid removal ease of the drainage bowl lids of Example 1, Example 5, and Examples 11-13

[0126]

[0127]

[0128] It can be seen from the test results in Table 3 that the drainage bowl lids prepared in the embodiments of the present invention have good lid removal ease.

[0129] As described above, it is only the specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A drainage bowl cover, characterized in that: The bowl cover body comprises an upper cover, a release layer and a lower cover which are arranged in sequence; the bowl cover body also comprises a first tongue piece and a second tongue piece which protrude outward; the upper cover is provided with a first knife line, the first knife line cuts through the upper cover, and the first knife line and the first tongue piece are combined to form a peelable sheet; a second knife line is provided between the first knife line and the first tongue piece, and the second knife line cuts through the lower cover; a third knife line is provided on the lower cover, and the third knife line cuts through the lower cover to form a plurality of drainage hole films; a plurality of micropores are provided in the release layer, and the release layer is also provided with through holes corresponding to the drainage hole films; The upper cover comprises a protective layer, an ink layer, and a printed film layer arranged in sequence from top to bottom, the lower cover comprises an adhesive layer, a barrier layer, and a heat-sealing layer arranged in sequence from top to bottom, and the release layer is arranged between the printed film layer and the adhesive layer; The printing film layer is PP synthetic paper or is composed of PP synthetic paper and PET.

2. The drain bowl cover according to claim 1, characterized in that: The components of the PP synthetic paper include polypropylene resin, inorganic filler and non-fluorescent physical brightener; the inorganic filler is calcium carbonate, and the weight percentage of the inorganic filler in the PP synthetic paper is 20-40%; the non-fluorescent physical brightener is titanium dioxide, and the weight percentage of the non-fluorescent physical brightener in the PP synthetic paper is 1-5%.

3. The drain bowl cover according to claim 2, characterized in that: The whiteness of the PP synthetic paper is ≥70%, and the surface tension of both sides of the PP synthetic paper is ≥38 dynes.

4. The drain bowl cover according to claim 3, characterized in that: The density of the PP synthetic paper is 0.6-0.95g / cm 3 , thickness is 30-100μm.

5. The drain bowl cover according to claim 1, characterized in that: The diameter of the micropores is 0.1-1.0 mm.

6. The drain bowl cover according to claim 1, characterized in that: The release layer includes one or more of nitrocellulose resin and wax.

7. The drain bowl cover according to claim 1, characterized in that: The protective layer is varnish or PET.

8. The drain bowl cover according to claim 1, characterized in that: The adhesive layer includes one or more of polyurethane adhesive and polyethylene resin; the barrier layer is at least one of a composite film of PET and aluminum foil, aluminum foil, aluminized PET, and aluminized OPP.

9. The drain bowl cover according to claim 1, characterized in that: The heat sealing layer is selected from one or more of polyurethane adhesive, coating resin and cast PE film.

10. The method for preparing the drainage bowl cover according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. After preparing the printed film layer, using a printing machine, printing an ink layer on one side of the printed film layer and printing a release layer on the other side of the printed film layer to obtain a first laminate; S2 using a printing press or a dry machine, the ink layer on one side of the first laminate to prepare a protective layer to obtain a cover; S3. Using a laminating machine to laminar the adhesive layer on one side of the release layer, and compounding the barrier layer on the adhesive layer to form a second laminate; S4. Using a laminating machine or a dry laminating machine, a heat-sealing layer is prepared on one side of the barrier layer of the second laminate to obtain a bowl cover roll film semi-finished product; S5. The bowl cover roll film semi-finished product is subjected to upper cover half die-cutting, lower cover half die-cutting, and outer contour die-cutting to obtain a drainage bowl cover.

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