Manufacturing method for paper food container, and manufacturing mold for paper food container

Abstract

A manufacturing method and mold for a paper food container. The manufacturing method comprises: folding a piece of paper to form a container body (11) of a food container, wherein the container body is open at the upper end, and has a bottom wall (12) and a peripheral wall adjacent to the bottom wall; forming at least one seam line on the bottom wall or the peripheral wall, wherein the seam line is located at a seam formed by the overlapping of at least two layers of sheet paper; then, placing the container body in a lower mold (80), and placing an airtight film (91) above the lower mold, wherein the airtight film is located above part of the region of the container body; and driving an upper mold (60) to move downwards, such that the airtight film is clamped between the upper mold and the container body, and heating the upper mold, such that the airtight film is closely fitted onto part of the region of the bottom wall and / or the peripheral wall of the container body so as to form an airtight film layer.

Description

Method for manufacturing paper food container, and mold for manufacturing paper food container TECHNICAL FIELD

[0001] The present application relates to the technical field of disposable tableware manufacturing, in particular to a method for manufacturing a paper food container using paper and a mold used in the method. BACKGROUND

[0002] Traditional disposable food containers are mostly made of plastic. Since plastic food containers are not easy to degrade and cause plastic pollution, disposable food containers made of environmentally friendly materials such as paper are becoming more and more popular.

[0003] Generally, a disposable food container made of paper is folded from a flat piece of kraft paper or cardboard. A seam line is formed at the folding position, and an airflow channel is formed at the seam. Gases inside the food container can leak to the outside through the seam, and gases from the outside can also flow into the food container through the seam, which results in poor air tightness of the food container.

[0004] In order to solve the problem of air tightness of the food container, a gas-tight film layer is usually covered on the surface of the food container. A multi-layer composite film is used, and a film layer with a very small thickness is made of PP, PE, PET, PA, EVOH, etc. The gas-tight film layer is attached to the inner surface of the food container by traditional vacuum suction molding, especially at the seam, and the seam is sealed by the gas-tight film layer to reduce the gas flow between the inside and outside of the food container.

[0005] However, since the gas-tight film layer is made of PP, PE, PET, PA, EVOH, etc., and not made of environmentally friendly materials such as paper, if the thickness of the gas-tight film layer is large, it will result in a high plastic content of the food container, for example, the weight of the gas-tight film layer accounts for more than 20% of the total weight of the food container, which does not meet the environmental protection requirements. For example, according to the legal requirements of the European Union, if the proportion of plastic in the food container exceeds 10%, the user needs to tear off the gas-tight film layer made of plastic from the food container when discarding the food container, and the gas-tight film layer and the container body made of paper need to be recycled separately. Obviously, if the weight of the gas-tight film layer is large, it not only does not meet the environmental protection requirements, but also brings great inconvenience to the user.

[0006] In addition, before the airtight film layer is attached to the inner surface of the food container by using the conventional vacuum suction method, a plastic film with a large area, a large thickness (the thickness is usually above 0.05 mm) and a certain hardness needs to be heated and softened first, then the softened plastic film is laid on the food container, and finally the softened plastic film is adhered to the food container by the vacuum suction method. However, the above process needs to consume a large amount of energy due to the heating of the plastic film, and the heating time is long, which increases the production time of the food container and leads to a high production cost of the food container.

[0007] In addition, when the plastic film is formed on the food container by using the conventional suction method, a suction equipment is needed, which usually includes a lower mold and an upper mold. The food container to be coated with the film is placed on the lower mold, and the plastic film is adhered to the food container by vacuumizing the lower mold during the suction, and then the softened plastic film is attached to the inner wall of the food container by heating. Therefore, the suction production equipment needs to be provided with a vacuumizing device, and the suction production equipment has many parts and a high production cost. TECHNICAL PROBLEM

[0008] The first object of the present application is to provide a paper food container manufacturing method with low production cost, low energy consumption and short production time.

[0009] The second object of the present application is to provide a manufacturing mold for producing a food container with good sealing performance and low plastic density. SOLUTION

[0010] To achieve the first object of the present application, the paper food container manufacturing method provided by the present application includes the following steps: folding a paper to form a container body of a food container, the container body has an open upper end, a bottom wall and a peripheral wall adjacent to the bottom wall, at least one seam line is formed on the bottom wall or the peripheral wall, the seam line is located at a seam formed by the superposition of at least two sheet-shaped paper materials, and an edge seam position is formed at the outer end of the seam line; then, placing the container body on a lower mold, placing an airtight film above the lower mold, and the airtight film is located above a part of the container body; driving an upper mold to move downward so that the airtight film is clamped between the upper mold and the container body; heating the upper mold so that the airtight film is tightly attached to a part of the bottom wall and / or the peripheral wall of the container body to form an airtight film layer, and the airtight film layer covers all the edge seam positions, and at least a part of the bottom wall and / or the peripheral wall is not covered by the airtight film layer.

[0011] In a preferred scheme, the number of airtight films placed above the lower mold is two or more, and each airtight film covers a part of the edge seam position.

[0012] Further, the air-tight film has a fitting portion and a clamping portion, a breaking portion is formed between the fitting portion and the clamping portion, and the breaking portion has discontinuously distributed breaking through holes.

[0013] Further, when the air-tight film is placed above the lower mold, the two ends of the clamping portion are tensioned by the tensioning member, and the fitting portion is located above the container body.

[0014] Further, the tensioning member includes a winding device that winds the air-tight film, or the tensioning member includes a clamping member that clamps the air-tight film.

[0015] To achieve the second object, the application provides a paper food container manufacturing mold, which comprises a lower mold, an upper mold, and a base plate.

[0016] Preferably, the number of the protrusions is two or more, and the adjacent two protrusions have a gap therebetween.

[0017] Further, the lower end of the protrusion is provided with a step portion, and the upper end surface of the step portion is higher than the lower end surface of the protrusion in the normal direction of the base plate.

[0018] Further, the lower mold has a flange supporting portion at the periphery of the mold cavity, and the base plate of the upper mold can press the flange portion of the container body on the flange supporting portion.

[0019] Further, the upper mold and / or the lower mold is provided with a heating device. Advantages

[0020] When the food container is manufactured by the method of the application, the container body is placed in the lower mold, and the air-tight film is laid on the container body. The air-tight film is attached to a part of the inner wall of the container body by the upper mold through hot pressing. Since the air-tight film layer is not formed by vacuum forming, the air-tight film does not need to be heated, and a soft air-tight film can be directly laid on the container body. The production time of the food container is short, and the energy consumption is low.

[0021] The food container manufactured by the method can prevent air leakage at the edge joint position of the food container by sealing the edge joint position by the air-tight film layer, thereby effectively improving the air-tightness of the food container. In addition, since the air-tight film layer is not covered on the entire area of the bottom wall and / or the peripheral wall of the food container, that is, the air-tight film layer is only covered on a part of the area of the bottom wall and / or the peripheral wall and covers all the edge joint positions, the covering area of the air-tight film layer on the food container is small, especially for the case that the bottom wall is relatively flat, the small covering area of the air-tight film layer on the bottom wall can reduce the area of the air-tight film layer, thereby reducing the weight of the air-tight film layer, reducing the proportion of the weight of the air-tight film layer in the total weight of the food container, meeting the environmental performance requirements, and the user does not need to tear off the air-tight film layer after use, which can facilitate the use of the user.

[0022] In addition, the air-tight film layer formed on the food container is not formed by a whole air-tight film, but is formed by a plurality of air-tight films respectively covering a part of the area of the food container, so that the inner wall of the food container is not entirely covered by the air-tight film layer, thereby ensuring that a part of the area is not covered by the air-tight film layer, and reducing the proportion of plastic in the food container.

[0023] The breaking part is arranged on the air-tight film, and when the upper die moves downward, the air-tight film will be broken along the breaking part and be attached to the inner wall of the food container under the action of the upper die, so that the processing of the food container is very convenient.

[0024] The air-tight film is tensioned by the tensioning member, which can ensure that the air-tight film is located at a specified position during production, thereby realizing positioning between the air-tight film and the food container and improving the qualified rate of the food container.

[0025] When the mold of the application is used to manufacture the food container, the air-tight film layer of the food container is formed on the inner wall of the container body by hot pressing, and since no vacuum suction treatment is required, the production equipment does not need to be provided with a vacuum suction device, and the air-tight film does not need to be heated and softened before being subjected to vacuum suction, so that the production time of the food container is short and the energy consumption is low. Since the entire bottom wall and peripheral wall of the produced food container are not covered by the air-tight film layer, the proportion of plastic is low, and the air-tight film layer does not need to be torn off after use of the food container.

[0026] In addition, the gap between the two adjacent protrusions of the food container does not form an air-tight film layer, which can reduce the volume of the protrusions, reduce the material of the lower die, and reduce the production cost of the mold. On the other hand, the area of the air-tight film layer of the manufactured food container is small, the proportion of plastic is low, and the environmental requirements are met.

[0027] The mold of the present application can flexibly set the shape of the protrusion according to the shape of the food container, and can ensure that the air-tight film layer can be tightly attached to the inner wall of the food container.

[0028] In addition, the air-tight film is placed on the flange portion of the food container, and after heat pressing, the flange portion of the food container is also covered with an air-tight film layer, which can improve the deformation resistance of the food container.

[0029] In addition, since the air-tight film layer is heat pressed to form on the container body, the upper die and / or the lower die need to be heated, and the heating device is directly arranged in the upper die and / or the lower die, which can improve the heating efficiency of the upper die and / or the lower die on the one hand, so that the upper die can be quickly heated, and on the other hand, avoids setting the heating device outside the mold to occupy a large volume, which is beneficial to the miniaturization of the production equipment. BRIEF DESCRIPTION OF DRAWINGS

[0030] FIG. 1 is a structure diagram of a food container from a first perspective according to an embodiment of the present application.

[0031] FIG. 2 is a structure diagram of a food container from a second perspective according to an embodiment of the present application.

[0032] FIG. 3 is a structure diagram of a kraft paper after being unfolded according to an embodiment of the present application.

[0033] FIG. 4 is a partial enlarged view of FIG. 3.

[0034] FIG. 5 is a structure diagram of a food container from a third perspective according to an embodiment of the present application.

[0035] FIG. 6 is a structure diagram of a food container from a fourth perspective according to an embodiment of the present application.

[0036] FIG. 7 is a sectional view of a food container according to an embodiment of the present application.

[0037] FIG. 8 is a structure diagram of a first perspective of a production mold and an air-tight film according to an embodiment of the present application.

[0038] FIG. 9 is a structure diagram of a second perspective of a production mold and an air-tight film according to an embodiment of the present application.

[0039] FIG. 10 is a structure diagram of a lower die according to an embodiment of the present application.

[0040] FIG. 11 is a structure diagram of a first perspective of an upper die according to an embodiment of the present application.

[0041] Fig. 12 is a structural view of the second perspective of the upper mold in the embodiment of the manufacturing mold of the paper-made food container according to the present application.

[0042] The present application will be further described in conjunction with the accompanying drawings and embodiments. Embodiment of the present application

[0043] The manufacturing method of the paper-made food container according to the present application first uses an environmentally friendly material such as paper to manufacture the container body of the food container, and then forms a gas-tight film layer on the container body by means of hot pressing, and the gas-tight film layer does not cover all the inner walls of the food container, but only covers a part of the area, thereby reducing the weight of the gas-tight film layer in the total weight of the entire food container.

[0044] Referring to Figs. 1 and 2, the food container 10 manufactured by using the manufacturing method of the paper-made food container according to the present application has a container body 11, which is folded from a whole piece of kraft paper, and the shape of the kraft paper before folding is shown in Fig. 3. The container body 11 has a flat bottom wall 12, and a peripheral wall is formed on the bottom wall 12. In this embodiment, the container body 11 has eight peripheral walls, which are sequentially arranged in a clockwise direction as shown in Fig. 1, and include peripheral walls 21, 22, 23, 24, 25, 26, 27, and 28. Among them, the peripheral wall 21 is adjacent to the peripheral walls 22 and 28, the peripheral wall 22 is adjacent to the peripheral walls 21 and 23, and so on. In addition, the lower edge of each of the peripheral walls 21, 22, 23, 24, 25, 26, 27, and 28 is adjacent to the bottom wall 12.

[0045] The container body 11 is an open container at the upper end, that is, the end of the container body 11 away from the bottom wall 12 is open, and no cover component is arranged. In use, the user places food into the container body, and then seals the open end of the container body 11 with a sealing film or the like. When the user needs to take out the food, the sealing film or the like needs to be first torn off from the open end of the container body 11.

[0046] Referring to Fig. 3, the container body 11 is folded from a whole piece of kraft paper, and preferably, the surface of the kraft paper is coated with a waterproof coating or a degradable coating, such as plastic film, e.g., PP, PE, PET, PA, EVOH, etc. For example, one surface of the kraft paper is coated with a plant fiber waterproof coating, and these waterproof coatings make the kraft paper itself have certain waterproof performance.

[0047] The kraft paper is provided with a plurality of folding lines, such as folding line 401, which is between the bottom wall 12 and the peripheral wall 21. When the kraft paper is folded along the folding line 401, the bottom wall 12 and the peripheral wall 21 of the container body 11 are formed. Similarly, when the kraft paper is folded along the folding line 402, the peripheral wall 22 of the container body is formed. When the kraft paper is folded along the folding line 403, the peripheral wall 23 of the container body 11 is formed. As can be seen, the bottom wall 12 and each of the peripheral walls 21, 22, 23, 24, 25, 26, 27 and 28 are formed by folding, and thus, the bottom wall 12 and each of the peripheral walls 21, 22, 23, 24, 25, 26, 27 and 28 are not provided with a joint line, and the bottom wall 12 itself is not provided with a joint line, and thus, the bottom wall 12 itself has good sealing performance.

[0048] The kraft paper 40 is provided with a folding portion at one corner thereof, which includes a sheet 41, which, when folded, forms the peripheral wall 26 of the container body 11. In addition, the sheet 41 is provided with folding sheets 42 and 44 on two sides thereof, and the folding sheet 42 is further provided with a sheet 43, which, when folded, forms the peripheral wall 27. When the kraft paper 40 is folded, the folding sheet 42 is folded between the sheet 41 and the sheet 43, i.e., on the container body 11 after being folded, and is clamped between the sheet 41 and the sheet 43, as shown in Fig. 5.

[0049] Thus, a joint line 31 is formed at the joint between the sheet 41 and the folding sheet 42, as shown in Fig. 6, and the joint line 31 is a gap formed by folding the sheet 41 and the folding sheet 42, i.e., a joint line is formed at the joint of two or more paper materials. The joint line 31 extends from the bottom wall 12 to the upper edge of the peripheral wall 27, as shown in Fig. 4, and an opening 49 is formed between the sheet 43 and the adjacent sheet 48, and thus, the position of the joint line 31 close to the opening 49 is a position where air leakage is prone to occur, which is the outer end of the joint line 31, i.e., the position close to the edge of the sheet, which is referred to as the edge joint position. Due to the edge joint position, the air in the container body 11 can pass through the edge joint position and communicate with the air outside. Correspondingly, a joint line 32 is also formed between the peripheral wall 25 and the peripheral wall 26. In this embodiment, all the joint lines are formed on the peripheral walls, and no joint line is formed on the bottom wall 12, and no joint line is formed between each of the peripheral walls and the bottom wall.

[0050] In order to form the air flow between the inside and outside of the container body 11 at the edge joint positions, the present embodiment needs to cover the container body 11 with a gas-tight film layer, and all the edge joint positions are covered by the gas-tight film layer to ensure the sealing of the food container 10. In the present embodiment, the gas-tight film layer is a film covering a partial area of the bottom wall 12 and / or the peripheral wall, for example, the film is a plastic film, a degradable film or a degradable coating made of PP, PE, PET, PA or EVOH, wherein the degradable film can be PLA, PBS, PVOH or PCL, and the gas-tight film layer should use a food-grade film to meet the requirements of food safety.

[0051] As shown in FIG. 2, the gas-tight film layers 60, 62 are only attached to a part of the bottom wall 12, such as the two ends along the length direction of the bottom wall 12, and thus, one end of the gas-tight film layer 60 extends to the folding mark between the bottom wall 12 and the peripheral wall 27, and the other end of the gas-tight film layer 60 forms an edge 61 on the bottom wall 12. Correspondingly, one end of the gas-tight film layer 62 extends to the folding mark between the bottom wall 12 and the peripheral wall 23, and the other end of the gas-tight film layer 62 forms an edge 63 on the bottom wall 12, and the area between the edges 61 and 63 is not covered by the gas-tight film layer, that is, the bottom wall 12 will not be covered by the gas-tight film layer in the area between the edges 61 and 63.

[0052] In this way, the gas-tight film layer does not cover the entire bottom wall 12, but only covers a part of the area. Preferably, the area of the bottom wall 12 covered by the gas-tight film layer is not more than 50% of the area of the bottom wall 12, and further, the area of the bottom wall 12 covered by the gas-tight film layer is not more than 10% of the area of the bottom wall 12. Since the bottom wall 12 is not provided with a joint line, there is no edge joint position, and the kraft paper 40 itself has good air tightness, even if a larger area of the bottom wall 12 is not covered by the gas-tight film layer, it will not affect the overall sealing performance of the food container 10.

[0053] Since all the edge joint positions are formed on the peripheral wall, in the present embodiment, the gas-tight film layer will cover all the peripheral wall, so that all the edge joint positions will be covered by the gas-tight film layer, and the good sealing performance of the gas-tight film layer is used to avoid air leakage between the inside and outside of the food container 10, and to ensure the sealing performance of the food container 10. Preferably, the weight of the gas-tight film layer is not more than 12% of the total weight of the food container 10, and further, the weight of the gas-tight film layer is not more than 5% of the total weight of the food container 10. In this way, the weight of the gas-tight film layer is very small, on the one hand, it can meet the requirements of environmental protection, and on the other hand, after the food container 10 is used, the user does not need to tear off the gas-tight film layer before throwing away the food container 10, which can facilitate the use of the user.

[0054] In other embodiments, the air-tight film layer can also only cover a part of the peripheral wall instead of covering the entire peripheral wall, which can further reduce the area of the air-tight film layer and make the air-tight film layer lighter. Of course, in order to ensure that the air-tight film layer can effectively seal all the edge joints, the air-tight film layer needs to completely cover the connecting edges to ensure the air-tight effect.

[0055] During use of the food container 10, the user often holds the peripheral wall. Since the peripheral wall is made of paper and has a soft texture, the peripheral wall is easily deformed when the user holds it. If the user holds it with a large force, the peripheral wall can be damaged, which can cause the entire food container 10 to be damaged and affect the use of the food container 10.

[0056] In order to improve the strength of the peripheral wall, a flange portion 51 is arranged at the upper edge of the peripheral wall, as shown in FIG. 7. The flange portion 51 is formed at the position of the peripheral wall 27 close to the open end, that is, at the upper edge of the peripheral wall 27 away from the bottom wall 12. The flange portion 51 extends from the upper edge of the peripheral wall 27 in a direction radially outward of the food container 10, that is, outwardly. As shown in FIG. 3, a flange sheet 46 is arranged at the end of the sheet body 43 away from the bottom wall 12. The flange sheet 46 and the sheet body 43 have a folding mark 406 therebetween. After the flange sheet 46 and the sheet body 43 are folded along the folding mark 406, the flange sheet 46 forms the flange portion 51.

[0057] In this embodiment, the upper edge of each peripheral wall is connected with a flange portion. Therefore, the flange portion is arranged around the upper edge of the entire peripheral wall, that is, around the open end of the food container 10. Further, the flange portion is also covered with an air-tight film layer. Preferably, the air-tight film layer is formed on the flange portion by hot pressing. In this way, the hardness of the flange portion is enhanced due to the hot-pressed air-tight film layer, thereby enhancing the strength of the peripheral wall and preventing the peripheral wall from being easily collapsed or damaged when the user holds it.

[0058] In addition, a folding portion 52 is arranged at the free end of the flange portion 51, as shown in FIG. 7. One end of the folding portion 52 is connected to the flange portion 51, and the free end of the folding portion 52 extends in a direction close to the bottom wall 12. In this embodiment, the folding portion 52 extends in a direction substantially perpendicular to the bottom wall 12. As shown in FIG. 3, an extending sheet 47 is arranged at the end of the flange sheet 46 away from the sheet body 43. The flange sheet 46 and the extending sheet 47 have a folding mark 407 therebetween. After the extending sheet 47 and the flange sheet 46 are folded along the folding mark 407, the extending sheet 47 forms the folding portion 52.

[0059] In addition, the edge folding part 52 can also be covered by a gas-tight film layer. Preferably, the gas-tight film layer is formed on the edge folding part 52 by hot pressing. The hot pressing method can improve the strength of the edge folding part 52, and further increase the deformation resistance of the edge folding part 52. Since the edge folding part 52 is connected to the upper edge of the peripheral wall 27, the strength of the peripheral wall 27 can be further improved, and the peripheral wall 27 is not easily collapsed even if the user holds the peripheral wall 27, so that the food container 10 can maintain the original shape.

[0060] In the manufacture of the food container, first, the container body 11 of the food container is manufactured. First, a whole piece of kraft paper is folded, for example, the kraft paper shown in FIG. 3 is cut. The surface of the kraft paper can be coated with a waterproof coating. Then, the container body 11 is folded. It should be noted that the edge folding part and the edge folding part are not formed on the container body 11 formed by folding. The edge folding part and the edge folding part are folded after the hot pressing of the gas-tight film layer is completed. Then, the container body 11 is placed in a mold, and the gas-tight film layer is formed on the container body 11 by hot pressing.

[0061] Referring to FIGS. 8 and 9, the mold includes an upper mold 60 and a lower mold 80. The upper mold 60 can move up and down relative to the lower mold 80, that is, the upper mold 60 can move close to or away from the lower mold 80. When the upper mold 60 moves upward, a gap is formed between the upper mold 60 and the lower mold 80 to facilitate the placement of the container body 11 into the lower mold 80 or the removal of the food container with the hot-pressed gas-tight film layer from the lower mold 80. In addition, the gas-tight films 91, 92 are also placed between the upper mold 60 and the lower mold 80.

[0062] Referring to FIG. 10, the lower mold 80 has a mold cavity 81, and the shape of the mold cavity 81 is the same as the outer contour of the container body 11. Therefore, when the container body 11 is placed in the mold cavity 81, the outer surface of the container body 11 can be attached to the inner surface of the mold cavity 81. In addition, the lower mold 80 is also provided with an edge folding support part 83, which surrounds the mold cavity 81. When the container body 11 is placed in the mold cavity 81, the edge folding part 52 of the food container is located on the edge folding support part 83.

[0063] Referring to FIGS. 11 and 12, the upper mold 60 has a base plate 61, and two protrusions 62, 63 are provided at the lower end of the base plate 61, that is, in the direction towards the lower mold 80. The two protrusions 62, 63 have a gap 84 therebetween. When the upper mold 60 moves downward, the two protrusions 62, 63 can extend into the mold cavity 81 of the lower mold 80. In addition, the shape of each protrusion 62, 63 at both ends in the length direction and the width direction of the upper mold 60 matches the shape of the mold cavity 81, but a small gap is formed between each protrusion 62, 63 and the mold cavity 81, which is used to accommodate the container body 11 and the gas-tight films 91, 92.

[0064] According to the shape of the food container to be made, the lower end of each protrusion 62, 63 is provided with a stepped portion 71, and the upper end surface 72 of the stepped portion 71 is higher than the lower end surface 70 of the protrusion 62, 63 in the normal direction of the base plate 61, wherein the lower end surface 70 of the protrusion 62, 63 is the end surface of the protrusion 62, 63 closest to the bottom wall of the mold cavity 81. Preferably, the shape of the stepped portion 71 is completely matched with the shape of the bottom wall of the container body 11, and the provision of the stepped portion 71 enables the air-tight film 91, 92 to be pressed and tightly fitted on the bottom wall of the container body 11 by the stepped portion 71, thereby avoiding the formation of a gap between the air-tight film layer and the bottom wall of the container body 11.

[0065] After placing the container body 11 into the mold cavity 81 of the lower mold 80, the peripheral wall and the bottom wall of the container body 11 are fitted on the inner surface of the mold cavity 81, and then two air-tight films 91, 92 are placed above the lower mold 81 as shown in FIG. 8. Since the container body 11 has also been placed in the mold cavity 81, the two air-tight films 91, 92 are also located above the container body 11. Preferably, there is a gap between the two air-tight films 91, 92, so the two air-tight films 91, 92 do not completely cover the entire container body 11. Since the air-tight films 91, 92 are formed by hot pressing on the peripheral wall and the bottom wall of the container body 11 to form an air-tight film layer, each air-tight film needs to cover a part of the edge joint position on the container body 11. Moreover, the two air-tight films 91, 92 need to cover all the edge joint positions on the container body 11 to ensure that the formed air-tight film layer can cover all the edge joint positions of the food container.

[0066] Taking the air-tight film 91 as an example, the air-tight film 91 has a fitting portion 94 and a clamping portion 93, and a fracture portion 95 is formed between the fitting portion 94 and the clamping portion 93. The fracture portion 95 has discontinuously distributed fracture through holes, for example, the fracture portion 95 includes a plurality of strip-shaped through holes, which can be circular through holes or long strip-shaped through holes. The two ends of the clamping portion 93 are tensioned by a tensioning member, so that the air-tight film 91 always remains in a state of tension before the upper mold 60 moves downward, i.e., remains in the state shown in FIG. 8. The position of the air-tight film 91 can be adjusted by the tensioning member, so that the air-tight film 91 can be accurately located above the container body 11, thereby ensuring that the air-tight film layer after hot pressing is just fitted on the specified position of the container body 11.

[0067] Preferably, the tensioning member includes a winding device, and the two ends of the air-tight film 91 are wound by the winding device. For example, the air-tight film 91 is a long strip-shaped film piece, which is wound by the winding device. During use, the winding device is used for unwinding and winding, thereby realizing automatic production. In other embodiments, the tensioning member can also include a clamping member, which clamps the two ends of the air-tight film 91 in the length direction. The shape of the air-tight film 92 is the same as that of the air-tight film 91, and is not described again.

[0068] After placing the air-tight films 91, 92 above the container body 11, the upper mold 60 is driven to move downward. Preferably, the upper mold 60 is driven by a driving mechanism such as a pneumatic cylinder or a motor. When the protrusions 62, 63 of the upper mold 60 abut against the air-tight films 91, 92, the air-tight films 91, 92 will be broken along the breaking portions 95 under the pressure of the protrusions 62, 63, so that the adhering portions 94 are clamped between the protrusions 62, 63 and the inner wall of the container body 11, while the clamping portions 93 are still tensioned by the tensioning members.

[0069] Preferably, the air-tight films 91, 92 should cover not only the peripheral wall and the bottom wall of the container body 11, but also the flange portion and the folded edge portion of the container body 11, so that the flange portion and the folded edge portion are both covered by the air-tight film layer. To this end, when the upper mold 60 moves downward, the base plate 61 of the upper mold 60 needs to press the flange portion of the container body 11 against the flange support portion 83, so that the adhering portions 94 also cover the areas corresponding to the flange portion and the folded edge portion.

[0070] Then, the upper mold 60 starts to heat. Preferably, at least one of the upper mold 60 or the lower mold 80 is provided with a heating device, and further, the two protrusions 62, 63 are respectively provided with heating wires. The heating temperature and the heating time of the upper mold 60 can be determined according to the material of the container body 11, the material of the air-tight films 91, 92, the thickness of the air-tight films 91, 92, the area of the adhering portions 94, and other factors. After being heated by the upper mold 60, the adhering portions 94 will be tightly adhered to the peripheral wall, the bottom wall, the flange portion and the folded edge portion of the container body 11, so as to form the air-tight film layer on the peripheral wall, the bottom wall, the flange portion and the folded edge portion of the container body 11. After a period of time, the upper mold 60 will move upward, so as to take out the semi-finished food container covered with the air-tight film layer from the lower mold 80.

[0071] Then, the semi-finished food container covered with the air-tight film layer is moved to the next station, and the mold for making the flange portion and the folded edge portion is used to press the semi-finished food container covered with the air-tight film layer, so as to form the flange portion and the folded edge portion on the upper edge of the peripheral wall. At this time, the food container is completed. Since the air-tight film layer has a certain toughness, the formation of the flange portion and the folded edge portion will not cause damage to the air-tight film layer. Moreover, since the air-tight film layer is pre-covered on the areas corresponding to the flange portion and the folded edge portion, the flange portion and the folded edge portion formed will both be covered by the air-tight film layer.

[0072] The food container made by the method of the application forms the airtight film layer on the local area of the bottom wall and / or the peripheral wall, instead of forming the airtight film layer on the entire bottom wall and / or the peripheral wall, thereby reducing the area of the airtight film layer and thereby reducing the weight of the airtight film layer in the entire food container, which can reduce the use of the airtight film layer on one hand, so that the food container is more environmentally friendly, and on the other hand, under the requirements of environmental performance and recycling, avoids the inconvenience to the user after using the food container.

[0073] In addition, the manufacturing process of the food container is not realized by using the suction molding method, but by using the hot pressing process, which does not need to use the vacuumizing equipment, thereby reducing the production equipment of the production equipment. And, since the airtight film is attached to the container body by the hot pressing process, this process does not require the thickness of the airtight film, and will not cause the airtight film to be damaged when vacuumizing due to the thickness of the airtight film being too small, so that the airtight film layer can be formed by using the airtight film with very small thickness, which can effectively reduce the plastic ratio of the food container. In addition, during the process of manufacturing the food container, the airtight film is not heated to soften it, so there is no waiting time for heating and softening the airtight film, which can improve the production efficiency of the food container, and also can reduce the energy consumed during the production of the food container.

[0074] Finally, it should be emphasized that the above is only the preferred embodiment of the application and is not intended to limit the application. For those skilled in the art, the application can have various changes and modifications, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application. Industrial applicability

[0075] The method and the mold of the application are used to manufacture paper food containers, and the paper food containers manufactured have low plastic content, which not only ensures airtightness but also meets the environmental protection requirements.

Claims

1. A method for manufacturing a paper food container, comprising: folding a paper to form a container body of a food container, the container body having an open upper end, a bottom wall, and a peripheral wall adjacent to the bottom wall, and at least one seam line is formed on the bottom wall or the peripheral wall, the seam line is located at a seam formed by at least two layers of sheet paper, and an outer end of the seam line forms an edge seam position; and characterized by: placing the container body on a lower mold, placing a gas barrier film above the lower mold, the gas barrier film being located above a portion of the container body; driving an upper mold to move downward so that the gas barrier film is clamped between the upper mold and the container body, heating the upper mold so that the gas barrier film is tightly attached to a portion of the bottom wall and / or the peripheral wall of the container body to form a gas barrier film layer, and all of the edge seam positions are covered by the gas barrier film layer, and at least a portion of the bottom wall and / or the peripheral wall is not covered by the gas barrier film layer. 2.The method for manufacturing a paper food container according to claim 1, characterized by: the number of the gas barrier films placed above the lower mold is two or more, and each of the gas barrier films covers a portion of the edge seam positions. 3.The method for manufacturing a paper food container according to claim 1 or 2, characterized by: the gas barrier film has an attachment portion and a clamping portion, a breaking portion is formed between the attachment portion and the clamping portion, and the breaking portion has discontinuously distributed breaking through holes. 4.The method for manufacturing a paper food container according to claim 3, characterized by: when the gas barrier film is placed above the lower mold, a tensioning member is used to tension two ends of the clamping portion so that the attachment portion is located above the container body. 5.The method for manufacturing a paper food container according to claim 4, characterized by: the tensioning member comprises a winding device that winds the gas barrier film; or the tensioning member comprises a clamping member that clamps the gas barrier film. 6.A manufacturing mold for a paper food container, comprising: a lower mold, the lower mold having an open upper end, and the lower mold forming a mold cavity in which a container body of a food container folded by a paper can be placed; and an upper mold arranged above the lower mold, the upper mold moving toward or away from the lower mold; and characterized by: the upper mold is provided with a base plate, and at least one protrusion is formed on the base plate toward the lower mold, the protrusion extending into the mold cavity of the lower mold, and a gas barrier film being clamped between the protrusion and the container body, and after the upper mold is heated, the gas barrier film is tightly attached to a portion of a bottom wall and / or a peripheral wall of the container body to form a gas barrier film layer, and at least a portion of the bottom wall and / or the peripheral wall is not covered by the gas barrier film layer. 7.The manufacturing mold for a paper food container according to claim 6, characterized by: the number of the protrusions is two or more, and adjacent two of the protrusions have a gap therebetween. 8.The manufacturing mold for a paper food container according to claim 7, characterized by: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A stepped portion is provided at the lower end of the protrusion, and in the normal direction of the substrate, the upper end face of the stepped portion is higher than the lower end face of the protrusion.

9. Paper food container manufacturing mold according to any one of claims 6 to 8, characterized in that: The lower mold has a flange support portion at the periphery of the mold cavity, and the base plate of the upper mold can press the flange portion of the container body on the flange support portion.

10. Paper food container manufacturing mold according to any one of claims 6 to 8, characterized in that: A heating device is provided in the upper mold and / or the lower mold.

Images