Leakproof packaging carton

Abstract

The utility model discloses a kind of anti-leakage packing cartons, it is related to packing box technical field, including box cover, and integrally formed and can be folded into the inner box body and outer box body of one upper end opening cubic, the inner box body after folding can be placed in the outer box body after folding inside and form box body, and the outer wall of the inner box body is contacted with the inner wall of the outer box body and fixed, the box cover can be buckled in the upper end opening place of the box body, the box cover, the inner box body and the outer box body are all made of paper material. The utility model can be used to bear with certain flowability and high moisture content content, and support strength is high, convenient to stack storage and transport.

Description

Technical Field

[0001] This utility model relates to the field of packaging box technology, and in particular to a leak-proof packaging paper box. Background Technology

[0002] Currently, for products like ice cream that have a certain degree of fluidity and high moisture content, the packaging boxes are usually made of plastic, which cannot solve the environmental and cost issues. A small number of paper packaging boxes are used, but they are mostly single-layered cylindrical boxes. When used to hold contents weighing more than 3kg, their support strength is insufficient, and they are not easy to stack, thus increasing the logistics and transportation costs and warehousing pressure of the packaging boxes. Utility Model Content

[0003] The purpose of this utility model is to provide a leak-proof packaging cardboard box to solve the problems existing in the prior art. It can be used to carry contents with a certain degree of fluidity and high moisture content, and has high support strength, making it easy to stack, store, and transport.

[0004] To achieve the above objectives, this utility model provides the following solution: This utility model provides a leak-proof packaging box, including a lid, an inner box body and an outer box body that are integrally formed and can be folded into a cube with an open top. The folded inner box body can be placed inside the folded outer box body to form a box body, and the outer wall of the inner box body contacts and is fixed to the inner wall of the outer box body. The lid can be fastened to the upper opening of the box body. The lid, the inner box body and the outer box body are all made of paper material.

[0005] Preferably, the outer box includes a first bottom plate, a second bottom plate, a third bottom plate, a fourth bottom plate, and a first side plate, a second side plate, a third side plate, and a fourth side plate connected in sequence. A first fold line is formed between the first side plate and the second side plate, and the first side plate can be folded around the first fold line to be perpendicular to the second side plate. A second fold line is formed between the second side plate and the third side plate, and the third side plate can be folded around the second fold line to be perpendicular to the second side plate. A third fold line is formed between the third side plate and the fourth side plate, and the fourth side plate can be folded around the third fold line to be perpendicular to the third side plate. The first bottom plate is connected to the first side plate. On one side, a fourth fold line is formed between the first base plate and the first side plate. The first base plate can be folded around the fourth fold line to be perpendicular to the first side plate. A fifth fold line is formed between the second base plate and the second side plate. The second base plate can be folded around the fifth fold line to be perpendicular to the second side plate. A sixth fold line is formed between the third base plate and the third side plate. The third base plate can be folded around the sixth fold line to be perpendicular to the third side plate. A seventh fold line is formed between the fourth base plate and the fourth side plate. The fourth base plate can be folded around the seventh fold line to be perpendicular to the fourth side plate. After folding, the outer box body forms a cube with an open top.

[0006] Preferably, the first base plate has a first slot in the middle of the side away from the fourth fold line, and two first tongues are formed on both sides of the first slot. The second base plate is a right-angled trapezoidal plate, and the inclined side of the second base plate is close to the first base plate. The second base plate has its lower base at the position corresponding to the fifth fold line, and a second tongue is provided at the upper base of the second base plate. The third base plate is an isosceles trapezoidal plate, and the lower base of the third base plate is at the position corresponding to the sixth fold line. A third tongue is provided at the upper base of the third base plate. The fourth base plate is a right-angled trapezoidal plate, and the inclined side of the fourth base plate is away from the third base plate. The bottom of the plate is located at the position corresponding to the seventh fold line. The top of the fourth bottom plate is provided with a fourth tongue. After folding, the second bottom plate and the fourth bottom plate are located outside the third bottom plate, and the first bottom plate is located outside the second bottom plate and the fourth bottom plate. The third tongue is used to insert into the first slot and press against the outer side of the middle part of the fourth bottom plate. The fourth side plate is also provided with an auxiliary side plate on the side away from the third fold line. An eighth fold line is formed between the fourth side plate and the auxiliary side plate. The auxiliary side plate can be folded around the eighth fold line to be perpendicular to the fourth side plate, and the auxiliary side plate is located inside the first side plate after folding.

[0007] Preferably, the first side panel on the side away from the first bottom plate, the second side panel on the side away from the second bottom plate, the third side panel on the side away from the third bottom plate, and the fourth side panel on the side away from the fourth bottom plate are all provided with a lower sealing edge. The lower sealing edge can be rotated outward to be perpendicular to the side wall of the outer box, and the lower sealing edge is located at the upper opening of the outer box. The lower sealing edge is used to connect to the upper sealing edge at the upper opening of the inner box.

[0008] Preferably, the inner box includes a rectangular base plate, a first long side plate and a second long side plate respectively connected to the two long sides of the rectangular base plate, and a first short side plate and a second short side plate respectively connected to the two short sides of the rectangular base plate. The first side of the first long side plate is connected to the first side of the first short side plate via a first connecting plate, the second side of the first long side plate is connected to the first side of the second short side plate via a second connecting plate, the first side of the second long side plate is connected to the second side of the first short side plate via a third connecting plate, and the second side of the second long side plate is connected to the second side of the second short side plate via a fourth connecting plate. A ninth fold line is formed between the first long side plate and the rectangular base plate, a tenth fold line is formed between the second long side plate and the rectangular base plate, an eleventh fold line is formed between the first short side plate and the rectangular base plate, and a twelfth fold line is formed between the second short side plate and the rectangular base plate. The first long side plate, the second long side plate, the first short side plate, and the second short side plate can all be folded around the corresponding fold line to form a cube perpendicular to the rectangular base plate and with an opening at the top. The first connecting plate, the second connecting plate, the third connecting plate, and the fourth connecting plate can all be folded to fit snugly against the outer wall of the inner box.

[0009] Preferably, the first connecting plate, the second connecting plate, the third connecting plate, and the fourth connecting plate have the same structure and each includes two triangular plates. A thirteenth fold line is formed between the two triangular plates, and the thirteenth fold line corresponds to one of the waists of the triangular plates. The other waists of the two triangular plates are respectively connected to the first long side plate, the second long side plate, the first short side plate, or the second short side plate. The two triangular plates can be folded around the thirteenth fold line, and after folding, the two triangular plates overlap and adhere to the outer wall of the first short side plate or the outer wall of the second short side plate.

[0010] Preferably, the first long side plate, the second long side plate, the first short side plate, and the second short side plate are all provided with upper sealing edges on the side away from the rectangular base plate. The upper sealing edges can be rotated outward to be perpendicular to the side wall of the inner box, and the upper sealing edges are located at the upper opening of the inner box. The upper sealing edges are used to connect the lower sealing edges at the upper opening of the outer box, and the inner wall of the outer box is fixedly connected to the outer wall of the inner box.

[0011] Preferably, the lid can be folded into a cube with one open end, and the open side of the lid is used to fasten to the upper end of the box body and seal the upper opening of the box body; the lid is a one-piece structure; or the lid includes a lid base, a rectangular top plate and four top side plates, the four top side plates are respectively connected to each side of the rectangular top plate, and each top side plate forms a top fold line with the rectangular top plate, each top side plate can be folded around the corresponding top fold line to be perpendicular to the rectangular top plate and fixed, and the lid base can be thermoformed or bonded to each of the top side plates to form the lid.

[0012] Preferably, after the inner box and the outer box are folded and the inner box is placed inside the outer box, the lower sealing edge and the upper sealing edge are positioned and fixedly connected, and the folded lid can be fastened to the upper end of the outer box.

[0013] Preferably, both the lower and upper sealing edges are made of paper material, and the lower and upper sealing edges are sealed together by a metal material; or, both the lower and upper sealing edges are made of paper material, and each of the lower and upper sealing edges has a plurality of perforations, which are connected by plastic snap fasteners; or, both the lower and upper sealing edges are made of paper material, and the lower and upper sealing edges are joined together by plastic retaining rings.

[0014] The present invention achieves the following technical advantages over the prior art: The leak-proof packaging box provided by this utility model includes a lid, an inner box body and an outer box body that are integrally formed and can be folded into a cube with an open top. The folded inner box body can be placed inside the folded outer box body to form the box body. The box body is used to hold contents with a certain degree of fluidity and high moisture content, such as ice cream or other chilled products. Because the box body is cubic in shape, it has good structural stability and can be stacked during transportation and storage, relieving transportation and storage pressure. The outer wall of the inner box body contacts and fixes the inner wall of the outer box body. The double-layer box body design of the inner and outer boxes improves the load-bearing capacity and support strength. The lid can be fastened to the upper opening of the box body to seal the contents of the box body. The lid, inner box body and outer box body are all made of paper material, which saves costs and meets environmental protection requirements. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the outer box in the unfolded state of this utility model; Figure 2 This is a schematic diagram of the inner box in the unfolded state in this utility model; Figure 3 This is a schematic diagram of the box lid in the unfolded state in this utility model; Figure 4 This is a schematic diagram showing the connection between the lower and upper sealing edges in this utility model; In the diagram: 100 - Outer box body, 200 - Inner box body, 300 - Box lid, 1 - First side panel, 2 - Second side panel, 3 - Third side panel, 4 - Fourth side panel, 5 - First bottom panel, 6 - Second bottom panel, 7 - Third bottom panel, 8 - Fourth bottom panel, 9 - First tongue, 10 - First slot, 11 - Second tongue, 12 - Third tongue, 13 - Fourth tongue, 14 - Auxiliary side panel, 15 - Lower edge seal, 16 - Rectangular bottom panel, 17 - First long side panel, 18 - Second long side panel, 19 - First short side panel, 20 - Second short side panel, 21 - First connecting plate, 22 - Second connecting plate, 23 - Third connecting plate, 24 - Fourth connecting plate, 25 - Upper edge seal, 26 - Rectangular top panel, 27 - Top side panel. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] The purpose of this utility model is to provide a leak-proof packaging cardboard box to solve the problems existing in the prior art. It can be used to carry contents with a certain degree of fluidity and high moisture content, and has high support strength, making it easy to stack, store, and transport.

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figures 1-4 As shown, this embodiment provides a leak-proof packaging box, including a lid 300, an inner box 200 and an outer box 100 that are integrally formed and can be folded into a cube with an open top. The folded inner box 200 can be placed inside the folded outer box 100 to form the box body. The box body is used to hold contents with a certain degree of fluidity and high moisture content, such as ice cream or other chilled products. Since the box body is cubic in shape, it has good structural stability and can be stacked during transportation and storage, relieving transportation and storage pressure. The outer wall of the inner box 200 contacts and is fixed to the inner wall of the outer box 100. The double-layer box design of the inner box 200 and the outer box 100 improves the load-bearing capacity and support strength. The lid 300 can be fastened to the upper opening of the box body to seal the contents of the box body. The lid 300, inner box 200 and outer box 100 are all made of paper material, which saves costs and meets environmental protection requirements.

[0021] Specifically, the outer box 100 includes a first base plate 5, a second base plate 6, a third base plate 7, a fourth base plate 8, and a first side plate 1, a second side plate 2, a third side plate 3, and a fourth side plate 4 connected sequentially. A first fold line is formed between the first side plate 1 and the second side plate 2, and the first side plate 1 can be folded around the first fold line to be perpendicular to the second side plate 2. A second fold line is formed between the second side plate 2 and the third side plate 3, and the third side plate 3 can be folded around the second fold line to be perpendicular to the second side plate 2. A third fold line is formed between the third side plate 3 and the fourth side plate 4, and the fourth side plate 4 can be folded around the third fold line to be perpendicular to the third side plate 3. In practice, the first, second, and third fold lines are not perfectly parallel, thus the first side plate 1, the second side plate 2, the third side plate 3, and the fourth side plate 4 are not perfectly regular rectangles, but isosceles trapezoids, designed as a kind of shape that folds... After folding, the upper opening area of ​​the outer box 100 is slightly larger than the lower base plate area. The first base plate 5 is connected to one side of the first side plate 1, and a fourth fold line is formed between the first base plate 5 and the first side plate 1. The first base plate 5 can be folded around the fourth fold line to be perpendicular to the first side plate 1. A fifth fold line is formed between the second base plate 6 and the second side plate 2. The second base plate 6 can be folded around the fifth fold line to be perpendicular to the second side plate 2. A sixth fold line is formed between the third base plate 7 and the third side plate 3. The third base plate 7 can be folded around the sixth fold line to be perpendicular to the third side plate 3. A seventh fold line is formed between the fourth base plate 8 and the fourth side plate 4. The fourth base plate 8 can be folded around the seventh fold line to be perpendicular to the fourth side plate 4. After folding, the outer box 100 forms a cube with an upper opening. At this time, the first base plate 5, the second base plate 6, the third base plate 7, and the fourth base plate 8 together form the base plate of the outer box 100.

[0022] As a preferred embodiment, when manufacturing the substrate of the outer box 100, 210g cardboard is first used as the surface substrate, and graphics are printed on its surface. After printing, a glossy film is applied to the printed surface of the 210g cardboard. The glossy film increases the surface gloss and abrasion resistance, while protecting the printed pattern from scratches or moisture. Next, the 210g cardboard with the glossy film is bonded together with E-flute core paper. On the other side of the E-flute core paper, another layer of 110g cardboard is bonded, and finally, a coating treatment is applied to the outer surface of this 110g cardboard layer. Those skilled in the art can also make adaptive adjustments to the material and weight of the above-mentioned papers according to actual needs.

[0023] The first base plate 5 has a first slot 10 in the middle of the side away from the fourth fold line. Two first tongues 9 are formed on both sides of the first slot 10. The second base plate 6 is a right-angled trapezoidal plate, with its sloping side close to the first base plate 5. The second base plate 6 has its lower base at the position corresponding to the fifth fold line, and a second tongue 11 is provided at its upper base. The third base plate 7 is an isosceles trapezoidal plate, with its lower base at the position corresponding to the sixth fold line, and a third tongue 12 is provided at its upper base. The fourth base plate 8 is a right-angled trapezoidal plate, with its sloping side away from the third base plate 7. The fourth base plate 8 has its lower base at the position corresponding to the seventh fold line, and a fourth tongue 13 is provided at its upper base. After folding, the second base plate 6 and... The fourth base plate 8 is located outside the third base plate 7, and the first base plate 5 is located outside the second base plate 6 and the fourth base plate 8. The third tongue 12 is used to insert into the first slot 10 and press against the outer side of the middle part of the fourth base plate 8, so that the first base plate 5, the second base plate 6, the third base plate 7 and the fourth base plate 8 together form the base plate of the outer box 100. This insertion method makes the bottom surface of the outer box 100 flatter. The fourth side plate 4 is also provided with an auxiliary side plate 14 on the side away from the third fold line. An eighth fold line is formed between the fourth side plate 4 and the auxiliary side plate 14. The auxiliary side plate 14 can be folded around the eighth fold line to be perpendicular to the fourth side plate 4. After the auxiliary side plate 14 is folded, it is located inside the first side plate 1, thereby improving the structural stability and sealing of the outer box 100.

[0024] The first side panel 1, the second side panel 2, the third side panel 3, and the fourth side panel 4 are all provided with a lower sealing edge 15 on the side away from the first bottom plate 5, the third side panel 3, the fourth side panel 4, and the fourth bottom plate 8. The lower sealing edge 15 can rotate outward to be perpendicular to the side wall of the outer box 100, and the lower sealing edge 15 is located at the upper opening of the outer box 100. The lower sealing edge 15 is used to connect the upper sealing edge 25 at the upper opening of the inner box 200, thereby improving the connection stability between the inner box 200 and the outer box 100. At the same time, when connecting the inner box 200 and the outer box 100, a heat sealing process can be used to heat seal the two together, or a spray adhesive process can be used to bond the inner box 200 and the outer box 100 together.

[0025] The inner box 200 includes a rectangular base plate 16, a first long side plate 17 and a second long side plate 18 respectively connected to the two long sides of the rectangular base plate 16, and a first short side plate 19 and a second short side plate 20 respectively connected to the two short sides of the rectangular base plate 16. The first side of the first long side plate 17 and the first side of the first short side plate 19 are connected by a first connecting plate 21, the second side of the first long side plate 17 and the first side of the second short side plate 20 are connected by a second connecting plate 22, the first side of the second long side plate 18 and the second side of the first short side plate 19 are connected by a third connecting plate 23, and the second side of the second long side plate 18 and the second side of the second short side plate 20 are connected by a fourth connecting plate. The plates 24 are connected, and the first long side plate 17 and the rectangular base plate 16 form a ninth fold line, the second long side plate 18 and the rectangular base plate 16 form a tenth fold line, the first short side plate 19 and the rectangular base plate 16 form an eleventh fold line, and the second short side plate 20 and the rectangular base plate 16 form a twelfth fold line. The first long side plate 17, the second long side plate 18, the first short side plate 19 and the second short side plate 20 can all be folded around the corresponding fold lines to form a cube that is perpendicular to the rectangular base plate 16 and has an opening at the top. The first connecting plate 21, the second connecting plate 22, the third connecting plate 23 and the fourth connecting plate 24 can all be folded to fit tightly against the outer wall of the inner box 200. When designing the inner box 200, the first long side plate 17, the second long side plate 18, the first short side plate 19, and the second short side plate 20 are all designed as isosceles trapezoidal structures. After folding, the upper opening area of ​​the inner box 200 is slightly larger than the area of ​​the rectangular base plate 16, and the acute angle between the sidewalls of the inner box 200 and the vertical direction is 3°. This results in the leak-proof packaging box having an inverted trapezoidal structure after processing, facilitating stacking and improving stability after stacking. Those skilled in the art can also make adaptive adjustments to the above angles during actual production.

[0026] As a preferred embodiment, the substrate of the inner box 200 is made of 317g white cardboard coated paper, which is die-cut and heat-sealed.

[0027] The first connecting plate 21, the second connecting plate 22, the third connecting plate 23, and the fourth connecting plate 24 have the same structure and each includes two triangular plates. A thirteenth fold line is formed between the two triangular plates, and the thirteenth fold line corresponds to one of the waists of the triangular plates. The other waist of the two triangular plates is connected to the first long side plate 17, the second long side plate 18, the first short side plate 19, or the second short side plate 20, respectively. The two triangular plates can be folded around the thirteenth fold line, and after folding, the two triangular plates overlap and adhere to the outer wall of the first short side plate 19 or the outer wall of the second short side plate 20. This not only improves the support and load-bearing effect, but also covers the corners of the inner box 200, which can play a role in sealing and strengthening the corner support to a certain extent.

[0028] The first long side plate 17, the second long side plate 18, the first short side plate 19, and the second short side plate 20 are all provided with an upper sealing edge 25 on the side away from the rectangular base plate 16. The upper sealing edge 25 can be rotated outward to be perpendicular to the side wall of the inner box 200, and the upper sealing edge 25 is located at the upper opening of the inner box 200. The upper sealing edge 25 is used to connect to the lower sealing edge 15 at the upper opening of the outer box 100. In this way, while improving the support strength of the box body, the presence of the lower sealing edge 15 and the upper sealing edge 25 can also firmly support the box at the vending terminal by means of the lower sealing edge 15 and the upper sealing edge 25. The inner wall of the outer box 100 is fixedly connected to the outer wall of the inner box 200.

[0029] The lid 300 can be folded into a cube with one open end. The open side of the lid 300 is used to fasten to the upper end of the box body and seal the upper opening of the box body. The lid 300 is a one-piece structure. Alternatively, the lid 300 includes a lid base, a rectangular top plate 26 and four top side plates 27. The four top side plates 27 are respectively connected to each side of the rectangular top plate 26, and each top side plate 27 forms a top fold line with the rectangular top plate 26. Each top side plate 27 can be folded around the corresponding top fold line to be perpendicular to the rectangular top plate 26 and fixed. The lid base can be thermoformed or bonded to each top side plate 27 to form the lid 300. Due to the presence of the lower sealing edge 15 and the upper sealing edge 25, it can also be firmly supported on the edge of the terminal cold drink freezer at the sales terminal by the lower sealing edge 15 and the upper sealing edge 25.

[0030] As a preferred embodiment, the substrate of the box cover 300 is made of 367g coated cardboard with a glossy film printed on it and then die-cut.

[0031] After the inner box 200 and the outer box 100 are folded and the inner box 200 is placed inside the outer box 100, the lower sealing edge 15 and the upper sealing edge 25 are positioned and fixedly connected. The box lid 300 is folded and can be fastened to the upper end of the outer box 100. In this embodiment, the shape of the box body is not limited to the above limitation. Those skilled in the art can also set it to other shapes of polygons according to actual needs.

[0032] Both the lower sealing edge 15 and the upper sealing edge 25 are made of paper material, and the lower sealing edge 15 and the upper sealing edge 25 are sealed with metal material; or, both the lower sealing edge 15 and the upper sealing edge 25 are made of paper material, and multiple perforations are provided on the lower sealing edge 15 and the upper sealing edge 25, and the perforations at the upper and lower positions are connected by plastic snap fasteners to achieve interlocking sealing; or, both the lower sealing edge 15 and the upper sealing edge 25 are made of paper material, and the lower sealing edge 15 and the upper sealing edge 25 are connected by plastic retaining rings. Those skilled in the art can also choose other connection methods according to actual needs.

[0033] This utility model uses specific examples to illustrate its design and implementation. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. Furthermore, those skilled in the art will recognize that, based on the idea of ​​this utility model, there will be changes in the specific implementation and application scope. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A leak-proof packaging cardboard box, characterized in that: The box includes a lid, an inner box and an outer box that are integrally formed and can be folded into a cube with an open top. The folded inner box can be placed inside the folded outer box to form a box body. The outer wall of the inner box contacts and is fixed to the inner wall of the outer box. The lid can be fastened to the upper opening of the box body. The lid, the inner box and the outer box are all made of paper material.

2. The leak-proof packaging box according to claim 1, characterized in that: The outer box includes a first bottom plate, a second bottom plate, a third bottom plate, and a fourth bottom plate, as well as a first side plate, a second side plate, a third side plate, and a fourth side plate connected in sequence. A first fold line is formed between the first side plate and the second side plate, and the first side plate can be folded around the first fold line to be perpendicular to the second side plate. A second fold line is formed between the second side plate and the third side plate, and the third side plate can be folded around the second fold line to be perpendicular to the second side plate. A third fold line is formed between the third side plate and the fourth side plate, and the fourth side plate can be folded around the third fold line to be perpendicular to the third side plate. The first bottom plate is connected to one side plate of the first side plate. The outer box has a fourth fold line between the first base plate and the first side plate, and the first base plate can be folded around the fourth fold line to be perpendicular to the first side plate. The second base plate and the second side plate have a fifth fold line, and the second base plate can be folded around the fifth fold line to be perpendicular to the second side plate. The third base plate and the third side plate have a sixth fold line, and the third base plate can be folded around the sixth fold line to be perpendicular to the third side plate. The fourth base plate and the fourth side plate have a seventh fold line, and the fourth base plate can be folded around the seventh fold line to be perpendicular to the fourth side plate. After folding, the outer box forms a cube with an open top.

3. The leak-proof packaging box according to claim 2, characterized in that: The first base plate has a first slot in the middle of the side away from the fourth fold line. Two first tongues are formed on both sides of the first slot. The second base plate is a right-angled trapezoidal plate, with its sloping side close to the first base plate. The second base plate has its lower base at the position corresponding to the fifth fold line, and a second tongue is provided at its upper base. The third base plate is an isosceles trapezoidal plate, with its lower base at the position corresponding to the sixth fold line, and a third tongue is provided at its upper base. The fourth base plate is a right-angled trapezoidal plate, with its sloping side away from the third base plate. The bottom is located at the position corresponding to the seventh fold line. The upper bottom of the fourth base plate is provided with a fourth tongue. After folding, the second base plate and the fourth base plate are located outside the third base plate, and the first base plate is located outside the second base plate and the fourth base plate. The third tongue is used to insert into the first slot and press against the outer side of the middle part of the fourth base plate. The fourth side plate is also provided with an auxiliary side plate on the side away from the third fold line. An eighth fold line is formed between the fourth side plate and the auxiliary side plate. The auxiliary side plate can be folded around the eighth fold line to be perpendicular to the fourth side plate, and the auxiliary side plate is located inside the first side plate after folding.

4. The leak-proof packaging box according to claim 2, characterized in that: The first side panel, the second side panel, the third side panel, and the fourth side panel are all provided with a lower sealing edge on the side away from the first bottom plate, the second side panel, the third side panel, and the fourth side panel. The lower sealing edge can be rotated outward to be perpendicular to the side wall of the outer box, and the lower sealing edge is located at the upper opening of the outer box. The lower sealing edge is used to connect to the upper sealing edge at the upper opening of the inner box.

5. The leak-proof packaging box according to claim 1, characterized in that: The inner box includes a rectangular base plate, a first long side plate and a second long side plate connected to the two long sides of the rectangular base plate, and a first short side plate and a second short side plate connected to the two short sides of the rectangular base plate. A first side of the first long side plate is connected to a first side of the first short side plate via a first connecting plate, a second side of the first long side plate is connected to a first side of the second short side plate via a second connecting plate, a first side of the second long side plate is connected to a second side of the first short side plate via a third connecting plate, and a second side of the second long side plate is connected to a second side of the second short side plate via a fourth connecting plate. A ninth fold line is formed between a long side plate and the rectangular base plate, a tenth fold line is formed between the second long side plate and the rectangular base plate, an eleventh fold line is formed between the first short side plate and the rectangular base plate, and a twelfth fold line is formed between the second short side plate and the rectangular base plate. The first long side plate, the second long side plate, the first short side plate, and the second short side plate can all be folded around the corresponding fold line to form a cube perpendicular to the rectangular base plate and with an opening at the top. The first connecting plate, the second connecting plate, the third connecting plate, and the fourth connecting plate can all be folded to fit snugly against the outer wall of the inner box.

6. The leak-proof packaging box according to claim 5, characterized in that: The first connecting plate, the second connecting plate, the third connecting plate, and the fourth connecting plate have the same structure and each includes two triangular plates. A thirteenth fold line is formed between the two triangular plates, and the thirteenth fold line corresponds to one of the waists of the triangular plates. The other waists of the two triangular plates are respectively connected to the first long side plate, the second long side plate, the first short side plate, or the second short side plate. The two triangular plates can be folded around the thirteenth fold line, and after folding, the two triangular plates overlap and adhere to the outer wall of the first short side plate or the outer wall of the second short side plate.

7. The leak-proof packaging box according to claim 5, characterized in that: The first long side plate, the second long side plate, the first short side plate, and the second short side plate are all provided with upper sealing edges on the side away from the rectangular base plate. The upper sealing edges can be rotated outward to be perpendicular to the side wall of the inner box, and the upper sealing edges are located at the upper opening of the inner box. The upper sealing edges are used to connect the lower sealing edges at the upper opening of the outer box. The inner wall of the outer box is fixedly connected to the outer wall of the inner box.

8. The leak-proof packaging box according to claim 7, characterized in that: The lid can be folded into a cube with one open end. The open side of the lid is used to fasten to the upper end of the box body and seal the upper opening of the box body. The lid is a one-piece structure. Alternatively, the lid includes a lid base, a rectangular top plate, and four top side plates. The four top side plates are respectively connected to each side of the rectangular top plate, and each top side plate forms a top fold line with the rectangular top plate. Each top side plate can be folded around the corresponding top fold line until it is perpendicular to the rectangular top plate and fixed. The lid base can be thermoformed or bonded to each of the top side plates to form the lid.

9. The leak-proof packaging box according to claim 8, characterized in that: After the inner box and the outer box are folded and the inner box is placed inside the outer box, the lower sealing edge and the upper sealing edge are positioned and fixedly connected, and the box lid is folded and can be fastened to the upper end of the outer box.

10. The leak-proof packaging box according to claim 9, characterized in that: Both the lower and upper sealing edges are made of paper material, and are sealed together by a metal material; or, both the lower and upper sealing edges are made of paper material, and each of the lower and upper sealing edges has a plurality of perforations, which are connected by plastic snap fasteners; or, both the lower and upper sealing edges are made of paper material, and are joined together by plastic retaining rings.

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