WO2025119180A1 - Sealing structure for packaging box, production process for sealing structure, and packaging box - Google Patents

Abstract

A sealing structure for a packaging box, a production process for a sealing structure, and a packaging box. The sealing structure comprises a base (2), a sealing cover (3) and a pull tab (4), wherein an opening is formed in the packaging box, the base (2) is arranged on the inner side of the opening, and a through hole is formed in the base (2); the sealing cover (3) has a closure portion, and when the sealing cover (3) is closed, the closure portion passes through the opening and is embedded into the through hole such that the closure portion tightly fits with the base (2) so as to close the opening; and the pull tab (4) is arranged on the outer side of the packaging box, and is fixedly connected to the sealing cover (3) and is configured to drive the sealing cover (3) to open or close the opening. The packaging box can be opened repeatedly, which reduces the production and manufacturing cost and is more environmentally friendly, and achieves better closure and convenience. In addition, the upper end of the base (2) wraps around the entire outer edge of the opening, thus improving the sealing performance of the opening of the packaging box and preventing leakage caused by liquid contents seeping into the paper base.

Description

Sealing structure of packaging box, production process of sealing structure and packaging box Technical Field

The present application relates to the technical field of product packaging, and in particular to a sealing structure of a packaging box, a production process of the sealing structure, and a packaging box.

Background Art

Non-carbonated liquid foods, such as drinking water, milk and yogurt, and semi-liquid foods, such as juice, are widely packaged and sold in three-dimensional packaging boxes. The packaging boxes for liquid or semi-liquid foods are usually made of paper-based composite packaging materials, which are composed of a multi-layer structure of a paper base layer, a barrier layer (such as aluminum foil), a waterproof layer, and an innermost layer. After the composite packaging materials are produced, they are shipped from the packaging material production enterprise to the food filling enterprise. The composite packaging materials are put into the filling machine of the filling enterprise and undergo multiple processes such as filling, sealing, and shaping to form liquid food packaging boxes.

Liquid food packaging boxes usually use disposable seals or plastic packaging covers for sealing. Plastic packaging covers not only have high production costs, but also produce a large amount of difficult-to-degrade plastic waste, which brings a heavy burden to the environment. Disposable seals used in liquid food packaging boxes, such as easy-pull stickers, have the advantages of being easy to open and low cost, and are very suitable for liquid food packaging, especially small-capacity liquid food packaging. However, on the one hand, the easy-pull stickers on the previous liquid food packaging boxes can only be opened once, and the opening cannot be closed again after opening, and cannot be reused, so that the liquid food packaging boxes with easy-pull stickers cannot be opened immediately after drinking, and are not convenient to carry. On the other hand, it is not easy to open the easy-pull stickers in the prior art, and it is easy to cause the opening to tear due to improper force during the opening process, and the liquid contents are splashed; the sealing and sanitary environment of the opening position of the liquid food packaging box are poor, especially for packaging boxes that have been placed for a long time, the opening is easy to accumulate dust or be contaminated by bacteria. If the packaging material at the opening is penetrated by the liquid contents when pouring, it is also easy to cause the opening to soften and deform, causing the liquid to leak.

Summary of the invention

In view of the above problems, the present application is proposed to provide a sealing structure of a packaging box, a production process of the sealing structure and a packaging box, so as to achieve the technical effects of repeatedly opening or closing the opening of the packaging box, improving the sealing of the opening of the packaging box, and preventing the penetration of liquid contents.

According to a first aspect of the present application, a sealing structure of a packaging box is provided, the sealing structure comprising: a base, a sealing cover and a pull tab,

The packaging box is provided with an opening, the base is arranged on the inner side of the packaging box at the position of the opening, and the base is provided with a through hole;

The sealing cover has a sealing portion. When the sealing cover is closed, the sealing portion passes through the opening and is embedded in the through hole. The sealing portion is tightly engaged with the base to seal the opening.

The pull tab is arranged on the outside of the packaging box, and the pull tab is fixedly connected to the sealing cover, and is used to drive the sealing cover to open or close the opening.

Optionally, when the sealing cover is closed, the outer edge of the sealing portion is tightly engaged with the inner edge of the through hole of the base to close the opening.

Optionally, a protrusion is provided on the outer edge of the closing portion, and a groove is provided on the inner edge of the through hole, and the protrusion abuts against the groove to close the opening.

Optionally, the protrusion has at least two different protrusion heights.

Optionally, the raised portion has a deep portion with a larger raised height and a shallow portion with a smaller raised height, the length ratio of the deep portion to the shallow portion is 1:(1-4), and the height ratio of the shallow portion to the deep portion is 1:(1.5-3); or the raised portion is a symmetrical structure, and the raised heights on both sides of the symmetry axis are gradually set.

Optionally, the base extends toward the outside of the packaging box along the edge of the opening to form a sealing ring, and the height of the sealing ring is not less than the height of the opening, so that the sealing ring completely covers the edge of the opening.

Optionally, the closing portion is a solid structure or a hollow structure.

Optionally, the closing portion is provided with an opening, or the closing portion is an annular structure, or a groove is provided on the closing portion, or the bottom surface of the closing portion is inclined.

Optionally, the sealing cover further comprises a top portion, the top portion is located outside the opening, and the pull tab is fixedly connected to the top portion.

Optionally, the sealing cover and the pull tab are integrally formed, or the sealing cover and the pull tab are formed separately and then fixedly connected.

Optionally, it also includes an inner membrane, which is arranged below the base. The area of the inner membrane is larger than that of the base. The inner membrane is fixedly connected to the closing portion. Before the sealing cover is opened for the first time, the inner membrane completely covers the base and is fixedly connected to the inner side of the packaging box; after the sealing cover is opened, the inner membrane ruptures.

Optionally, it also includes: an outer film, which is arranged on the outside of the packaging box at the opening position, the area of the outer film is smaller than the area of the pull tab, and before the sealing cover is opened for the first time, the pull tab is fixedly connected to the outer film; after the sealing cover is opened, the pull tab is separated from the outer film.

According to the second aspect of the present application, a production process of a packaging box sealing structure is provided, and the production process includes:

Step a, punching holes in the composite packaging material used to prepare the packaging box to form an opening;

Step b, setting a base at the opening position on the inner side of the corresponding packaging box, wherein the base is provided with a through hole;

Step c, providing a sealing cover, wherein the sealing cover has a sealing portion, the sealing portion passes through the opening and is embedded in the through hole, and the sealing portion is tightly engaged with the base to seal the opening;

Step d, a pull tab is arranged on the outside of the packaging box, and the pull tab is fixedly connected to the sealing cover to drive the sealing cover to open or close the opening.

Optionally, the production process further comprises:

Step e: an inner film is arranged below the base, the area of the inner film is larger than the area of the base, the inner film completely covers the base and is fixedly connected to the closing portion and the inner side of the packaging box.

Optionally, the production process also includes setting an outer film, setting the outer film at the opening position on the outside of the corresponding packaging box, and the area of the outer film is larger than the area of the opening; or setting the outer film on the composite packaging material on the outside of the corresponding packaging box, and then punching holes in the outer film to form an opening.

According to a third aspect of the present application, a packaging box is provided, on which a sealing structure as described in any one of the first aspects above is provided, or the packaging box is provided with a sealing structure prepared according to any one of the production processes described in the second aspect above is provided.

Optionally, the packaging box is made of a composite packaging material, and the composite packaging material includes a base layer, a printing layer, a waterproof layer and an innermost layer.

As can be seen from the above, at least one of the above technical solutions adopted in the embodiment of the present application can achieve the following beneficial effects: a sealing structure of a packaging box is provided, including: a base, a sealing cover and a pull tab. By setting the base on the inside of the packaging box, the sealing cover passes through the opening and tightly engages with the base on the inside of the packaging box and closes the opening. The base is set on the inside of the packaging box, which not only reduces the occupation of the base on the outer surface space of the packaging box, but also makes the appearance of the packaging box more concise and beautiful, and is convenient for transportation and display; it can also make the closure of the opening more secure and safe, avoiding the risk of accidentally opening the sealing cover due to external force when the base is set on the outside of the packaging box, and at the same time prevent dust and debris from entering from the external gap, making it cleaner. The pull tab connected to the sealing cover can not only drive the sealing cover to repeatedly open or close the opening, realize the reusable sealing structure of the packaging box, and make the packaging box more convenient to use and carry, but also can shield the opening, further ensure the sanitary and safe environment at the opening, and improve the food safety of the packaging box.

The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

FIG1 is a longitudinal cross-sectional view of a sealing structure in one embodiment of the present application;

FIG2 is an enlarged view of portion A in FIG1 ;

FIG3 is a longitudinal cross-sectional view of a sealing structure in another embodiment of the present application;

FIG4 is a longitudinal cross-sectional view of a sealing structure in yet another embodiment of the present application;

FIG. 5 is a flow chart of the production process of the sealing structure of the packaging box in the present application.

In the figure: 1. composite packaging material; 2. base; 3. sealing cover; 4. pull tab; 5. inner film; 6. outer film; 7. sealing ring; 8. raised part.

DETAILED DESCRIPTION

The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

In one embodiment of the present application, a sealing structure of a packaging box is proposed. The packaging box can be made of a composite packaging material. The composite packaging material generally includes a base layer, a printing layer, a waterproof layer and an innermost layer. Among them, the base layer of the composite packaging material generally adopts base paper, such as white-bottomed paper or kraft-bottomed paper. The base layer can provide the necessary stiffness for the composite packaging material so that the packaging box maintains a stable shape. The composite packaging material can also include a barrier layer, which plays a key role in the shelf life of liquid food. It prolongs the shelf life of food by preventing oxygen from penetrating into the interior of the packaging container. Aluminum foil is usually used as a barrier layer in the composite packaging material. The waterproof layer is generally a thermoplastic resin, preferably a polyolefin, including but not limited to low-density polyethylene (LDPE), metallocene polyethylene (m-PE) or a mixture of the two. The waterproof layer is located on the outermost side of the composite packaging material, which can provide waterproof and dustproof properties and protect the printed layer of the composite packaging material from wear. The innermost layer of the composite packaging material is in direct contact with the packaging contents. The innermost layer is generally a thermoplastic resin, preferably containing polyolefins, such as polyethylene (PE), including but not limited to linear low-density polyethylene (LLDPE), ultra-low-density polyethylene, low-density polyethylene, metallocene polyethylene or a mixture thereof. An adhesive layer is generally provided between the base layer and the barrier layer, and between the barrier layer and the innermost layer. The adhesive layer plays a bonding role between two adjacent layers, and generally adopts an adhesive polymer layer, such as a modified polypropylene-based thermoplastic adhesive polymer. An opening is provided on the packaging box as an outlet for the contents of the package to flow out or drink. The opening is achieved by punching holes in the composite packaging material with a punching device, and a sealing structure is correspondingly provided at the location of the opening for repeated opening and closing of the opening.

In this embodiment, as shown in FIG1 , the sealing structure includes: a base 2, a sealing cover 3 and a pull tab 4. An opening is provided on the composite packaging material 1, and the base 2 is provided on the inner side of the packaging box at the opening position; unless otherwise specified in the present application, the outer side refers to the side facing the external air, and the inner side refers to the side facing the package contents. A through hole is provided on the base; the sealing cover has a closing portion, and when the sealing cover is closed, the closing portion passes through the opening and is embedded in the through hole, and the closing portion is tightly engaged with the base to close the opening. The base is arranged on the inner side of the packaging box, and the closing portion of the sealing cover is tightly combined with the base on the inner side of the packaging box to close the opening, which reduces the occupation of the base on the outer surface of the packaging box, not only making the appearance of the packaging box more concise and beautiful, but also facilitating the stacking and display of the packaging box in transportation and display racks; in addition, the base is arranged on the inner side of the packaging box, which is more concealed and safe for closing the opening, reducing the risk of the sealing cover opening due to inadvertent external force when the base is exposed to the outside of the packaging box; and it can also have a dustproof effect.

Preferably, the opening can be set to be teardrop-shaped or circular, and the shape of the through hole of the base 2 and the sealing cover 3 can also be adjusted to teardrop-shaped or circular accordingly. Of course, the shape, size, material, etc. of the opening, base and sealing cover are not limited in the embodiments of the present application. The above is only for the convenience of understanding and simplified description, and cannot be regarded as a limitation of the present application. After the sealing structure is opened, the sealing cover 3 can be pulled out and/or pressed back from the base 2 fixed on the opening, such as pressing the sealing cover 3 to embed it into the base 2 to achieve the closure of the opening.

The material for preparing the base 2 and the sealing cover 3 can be one or more of plastic, paper, paper-plastic composite materials, cellulose (such as modified cellulose, natural cellulose, artificial cellulose, dry molded fiber and other cellulose products or cellulose materials), degradable biomaterials, etc.; specifically, the base 2 and the sealing cover 3 can be prepared by injection moldable materials, such as plastic, specifically PE (Polyethylene), preferably LDPE (Low Density Polyethylene), HDPE (High Density Polyethylene), or PP (Polypropylene), PA (Polyamide), PLA (Polylactic Acid) or PBAT (Butyleneadipate-co-terephthalate), etc., or any combination of several of them, such as a combination of PE/PLA.

Preferably, the materials used to make the base 2 and the sealing cover 3 are both elastic. For example, if the sealing cover 3 or the base 2 is made of elastic materials such as food-grade silicone, rubber or polyethylene, the overall size or partial size of the sealing cover 3 can be slightly larger than the size of the opening and the through hole on the base 2, so that the sealing cover 3 and the base 2 can seal the opening more tightly without affecting the sealing cover passing through the opening and embedding into the base.

The sealing structure also has a pull tab 4. Preferably, the area of the pull tab 4 is larger than the area of the opening. The pull tab 4 is arranged on the outside of the packaging box and is located above the sealing cover 3. The sealing cover 3 is fixedly connected to the pull tab 4. The pull tab 4 serves as a force-bearing component to drive the sealing cover 3 to open or close the opening, making the opening and closing easier to operate. In addition, the pull tab 4 can also shield and protect the opening to prevent dust and other impurities from falling near the opening and entering the opening when it is opened, making the use of the packaging box safer and more hygienic.

Since the cooperation connection between the base 2 and the sealing cover 3 in the present application includes but is not limited to detachable connection methods such as snap connection, when the sealing cover 3 is pulled open from the closed state to the open state, the pull tab 4 drives the sealing cover 3 to separate from the through hole of the base 2 under the action of external force. Therefore, the sealing cover in the present application can be embedded in the through hole of the base under the action of external force to cooperate with the base to close the opening, and can also be separated from the through hole of the base under the action of external force, thereby realizing the reusability of the opening of the packaging box, reducing the production cost and being more environmentally friendly.

Preferably, the pull tab 4 can be integrally formed with the sealing cover 3, such as by injection molding to prepare the pull tab and the sealing cover as a whole; the pull tab 4 and the sealing cover 3 can also be separately formed and then fixedly connected, such as the prepared sealing cover 3 also includes a top, the top is located outside the opening, the pull tab is fixedly connected to the top of the sealing cover, and the connection method can be hot-melt connection or adhesive bonding. The pull tab 4 can be prepared by a composite material, which can be a composite material including a barrier material and a fusible material, the barrier material is at least one of aluminum foil, barrier paper, and cellulose material, and the fusible material is at least one selected from plastic, PLA or PBAT. For example, the pull tab 4 is a composite of barrier paper (such as nanocellulose paper) and PE or a composite of aluminum foil and PE. Among them, the barrier paper or aluminum foil can also be replaced by LDPE (Low-density Polyethylene), HDPE (High Density Polyethylene), PP (Polypropylene), PA (Polyamide), PLA (Polylactic Acid) or PBAT (Butyleneadipate-co-terephthalate). The pull tab 4 can also be made of a single material, such as cardboard, preferably a cardboard with a certain hardness and stiffness, preferably the cardboard for preparing the pull tab has a gram weight of 300g-800g, and further preferably the cardboard thickness is 2-5mm; the pull tab 4 can also be made of cellulose material, such as by dry compression molding technology, wood pulp or cellulose material compression molding to prepare the pull tab. Select the corresponding fixing method according to the material of the pull tab. If the pull tab 4 includes aluminum foil and PE, the pull tab can be fixed by electric heating. By electromagnetic induction, the aluminum foil in the pull tab 4 is heated, and the PE is melted by the heat. The pull tab 4 is fixed and bonded to the top of the sealing cover or the composite packaging material 1 for preparing the packaging box. The PE in the pull tab can also be replaced by PP, PA, PLA or PBAT. If the pull tab is made of cardboard, the sealing cover and the pull tab can also be fixedly connected by gluing and fixing them by adhesives after they are formed separately.

Further, FIG. 2 is an enlarged view of the portion A in FIG. 1 . As shown in FIG. 2 , when the sealing cover is closed, the outer edge of the sealing portion is preferably tightly engaged with the inner edge of the through hole of the base to close the opening. More preferably, a protrusion 8 is provided on the outer edge of the sealing portion, and a groove is provided on the inner edge of the through hole. When the sealing cover is closed, the protrusion 8 of the sealing portion abuts against the groove of the through hole to close the opening. The matching connection between the protrusion 8 and the groove can further enhance the sealing performance of the sealing cover 3 and the base 2 for the opening, and effectively prevent the liquid content from seeping out from the gap between the sealing cover 3 and the base 2. Preferably, the protrusion 8 has at least two different protrusion heights, such as the protrusion 8 has a deep part with a larger protrusion height and a shallow part with a smaller protrusion height. It is further preferred that the length ratio of the deep part to the shallow part is 1:(1-4), and the height ratio of the shallow part to the deep part is 1:(1.5-3); or the protrusion 8 is a symmetrical structure, and the protrusion heights on both sides of the symmetry axis are gradually set, such as gradually increasing or decreasing. The depth of the through hole groove is set in accordance with the protruding height of the protruding portion 8. By setting the height of the protruding portion 8 and the corresponding depth of the groove, the tightness of the combination of the protruding portion and the groove and the opening force can be more flexibly balanced and adjusted, so that the opening and closing of the sealing structure have both good sealing and convenience. For example, after installation, the shallow part of the protruding portion 8 faces or is close to the lifting position of the handle, which can make the sealing structure easier to open; the higher the proportion of the shallow part to the length of the protruding portion 8, the easier it is to open; the higher the proportion of the deep part to the length of the protruding portion 8, the better and more secure the sealing is.

Furthermore, as shown in FIG. 2 , the base extends along the edge of the opening toward the outside of the packaging box to form a sealing ring 7, and the height of the sealing ring 7 is not less than the height of the opening. Since the sealing ring 7 at the upper end of the base can completely cover and wrap the edge of the opening, the sealing ring 7 can further improve the sealing of the packaging box opening, especially for packaging boxes made of paper-based composite packaging materials, thereby preventing liquid contents from penetrating into the interior of the packaging material when pouring, causing the opening to soften and deform and cause leakage.

Further, the closing part may be a solid structure, and preferably the closing part may also be a hollow structure with a hollow interior, and the hollow structure may reduce the amount of material used in preparing the closing part and enhance the elasticity; referring to FIG. 2 , preferably, the closing part may also adopt a hollow structure, and an annular groove is provided at a position close to the edge of the closing part; or referring to FIG. 3 , preferably, a hole is opened on the closing part or a closing part with an annular structure is adopted,

The annular groove, opening, and annular structure of the sealing part not only help to further reduce the amount of material used, but also make the sealing part more elastic and easier to insert or remove from the through hole on the base. In addition, preferably, the bottom surface of the sealing part can also be inclined so that the thinner side of the sealing part is closer to the force position of the pull tab, making it easier to pull the sealing part out of the base.

Furthermore, the sealing structure further comprises an inner film 5, which is arranged below the base, and the area of the inner film 5 is larger than the area of the base 2. The inner film 5 is fixedly connected to the bottom of the closed part and the inner side of the packaging box near the base 2. Before the sealing cover is opened for the first time, the inner film completely covers the bottom of the closed part and the base. When the sealing cover is opened for the first time, the bonding force between the inner film 5 and the bottom of the closed part is greater than the tear strength of the inner film, so that the inner film is broken, and the sealing cover 3 can be smoothly separated from the through hole of the base 2, thereby realizing the opening of the opening. The inner film is fixedly connected to the inner side of the packaging box and the base is completely covered in the inner film, which can effectively improve the sealing performance of the packaging box, especially prevent the packaging box from being compressed before opening, resulting in leakage of liquid contents; in addition, the inner film 5 can further ensure the sterile safety of the internal environment of the packaging box before the first opening, and extend the shelf life of the packaging contents. The inner film 5 can be a PE (Polyethylene, polyethylene) film or a composite film, such as PE laminated on both sides of the EVOH (Ethylene vinyl alcohol copolymer, ethylene/vinyl alcohol copolymer) material to form a PE/EVOH/PE composite material. EVOH can also be replaced by vapor-deposited films of metal oxides such as PVOH (Polyvinyl Alcohol), PVDC (Poly-vinylidene Chloride), PA (Polyamide) or Al ₂ O ₃ .

Furthermore, the sealing structure also includes an outer film 6. In this embodiment, the outer film 6 is arranged on the outside of the packaging box at the opening position. The area of the outer film is smaller than the area of the pull tab. The pull tab is fixedly connected to the outer film so that the outer film 6 is located between the pull tab 4 and the waterproof layer around the opening. The outer film 6 can prevent the pull tab 4 from directly adhering to the outermost waterproof layer of the packaging box when opening, which causes the pull tab 4 to damage the waterproof layer of the composite packaging material 1 when it is pulled up. The outer film 6 can be PE (Polyethylene), and the outer film 6 can also be prepared by a composite material of OPP (Oriented Polypropylene) and PE, wherein OPP can also be replaced by polyester materials such as HDPE, PP, PET/PBT, etc.

In another embodiment of the present application, as shown in FIG. 4 , a production process of a packaging box sealing structure is also proposed, and the production process includes:

Step a, punching holes in the composite packaging material used to prepare the packaging box to form an opening;

Step b, setting a base at the opening position on the inner side of the corresponding packaging box, wherein the base is provided with a through hole;

Step c, providing a sealing cover, wherein the sealing cover has a sealing portion, the sealing portion passes through the opening and is embedded in the through hole, and the sealing portion is tightly engaged with the base to seal the opening;

Step d, a pull tab is arranged on the outside of the packaging box, and the pull tab is fixedly connected to the sealing cover to drive the sealing cover to open or close the opening.

Furthermore, in another embodiment of the production process, it can also include: step e, setting an inner film under the base, the area of the inner film is larger than the area of the base, the inner film is fixedly connected to the closing part, and the inner film completely covers the base and is fixedly connected to the inner side of the packaging box.

Furthermore, the production process may also include setting an outer film, setting the outer film at the opening position on the outside of the corresponding packaging box, and the area of the outer film is larger than the area of the opening; or setting the outer film on the composite packaging material on the outside of the corresponding packaging box, and then punching holes in the outer film to form an opening.

Specifically, the sealing cover and the base can be made by injection molding; when fixedly connected, the base can be first set at the opening position on the inner side of the packaging box, and then the inner film covers the base and is fixedly connected to the inner side of the packaging box; the base can also be fixedly connected to the inner film, and then the base is set on the inner side of the opening of the packaging box, and the inner film is fixedly connected to the inner side of the packaging box; the pull tab and the sealing cover can be integrally formed first, and then set on the packaging box; the sealing cover can also be set on the packaging box first, and then the pull tab is fixedly connected to the sealing cover. The fixed connection method can be heat sealing, or bonding with an adhesive. Of course, the above description of the fixing order between the outer film, the inner film, the sealing cover, the base and the pull tab is only an exemplary description and cannot be understood as a limitation to the present application.

In one embodiment of the present application, a packaging box is also disclosed. The packaging box is made of a composite packaging material. The composite packaging material is first sealed longitudinally to form a tube and filled, and then continuously transversely sealed at a distance of a single package. The packaging box is cut in the middle of the transverse seal and shaped into an independent packaging box. The packaging box is provided with a sealing structure as described above, or the packaging box is provided with a sealing structure prepared according to any of the above production processes. The packaging box can realize repeated opening and closing of the packaging box opening, which is not only more environmentally friendly, but also improves the sealing of the opening. Preferably, the packaging box is made of a composite packaging material, and the composite packaging material includes a base layer, a printing layer, a waterproof layer and an innermost layer. Preferably, the base layer is a paper base layer.

In summary, the technical solution of the present application has achieved at least the following technical effects: by setting a base at the opening position on the inner side of the packaging box, and setting a sealing cover and a pull tab on the outer side of the packaging box, the sealing cover can be embedded in the through hole of the base and connected with the base under the action of external force, and can also be separated from the through hole of the base under the action of external force, thereby realizing the reusable use of the packaging box opening, reducing the production cost and being more environmentally friendly; the setting of the pull tab and the base hidden on the inside of the packaging box can further improve the food safety when the packaging box is used.

It should be noted that, in the description of the present invention, unless otherwise specified, "plurality" means two or more. In the present invention, unless otherwise clearly specified and limited, the terms such as "connection" and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

The above is only a specific embodiment of the present invention. Under the above teachings of the present invention, those skilled in the art can make other improvements or modifications on the basis of the above embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of the present invention, and the protection scope of the present invention shall be based on the protection scope of the claims.

Claims (17)

A sealing structure for a packaging box, characterized in that the sealing structure comprises: a base, a sealing cover and a pull tab, The packaging box is provided with an opening, the base is provided on the inner side of the packaging box at the position of the opening, and the base is provided with a through hole; The sealing cover has a sealing portion. When the sealing cover is closed, the sealing portion passes through the opening and is embedded in the through hole. The sealing portion is tightly engaged with the base to seal the opening. The pull tab is arranged on the outside of the packaging box, and the pull tab is fixedly connected to the sealing cover, and is used to drive the sealing cover to open or close the opening. The sealing structure according to claim 1 is characterized in that, when the sealing cover is closed, the outer edge of the sealing portion is tightly engaged with the inner edge of the through hole of the base to close the opening. The sealing structure according to claim 2 is characterized in that a protrusion is provided on the outer edge of the sealing portion, a groove is provided on the inner edge of the through hole, and the protrusion abuts against the groove to close the opening. The sealing structure according to claim 3 is characterized in that the protrusion has at least two different protrusion heights. The sealing structure according to claim 4 is characterized in that the raised portion has a deep portion with a larger raised height and a shallow portion with a smaller raised height, the length ratio of the deep portion to the shallow portion is 1:(1-4), and the height ratio of the shallow portion to the deep portion is 1:(1.5-3); or the raised portion is a symmetrical structure, and the raised heights on both sides of the symmetry axis are gradually set. The sealing structure according to claim 1 is characterized in that the base extends toward the outside of the packaging box along the edge of the opening to form a sealing ring, and the height of the sealing ring is not less than the height of the opening, so that the sealing ring completely covers the edge of the opening. The sealing structure according to claim 1 is characterized in that the sealing portion is a solid structure or a hollow structure. The sealing structure according to claim 7 is characterized in that the sealing portion is provided with an opening, or the sealing portion is an annular structure, or the sealing portion is provided with a groove, or the bottom surface of the sealing portion is inclined. The sealing structure according to claim 1 is characterized in that the sealing cover also includes a top, the top is located outside the opening, and the pull tab is fixedly connected to the top. The sealing structure according to claim 1 is characterized in that the sealing cover and the pull tab are integrally formed; or the sealing cover and the pull tab are formed separately and then fixedly connected. The sealing structure according to claim 1 is characterized in that it also includes an inner film, which is arranged below the base, the area of the inner film is larger than the area of the base, the inner film is fixedly connected to the closing portion, and before the sealing cover is opened for the first time, the inner film completely covers the base and is fixedly connected to the inner side of the packaging box; after the sealing cover is opened, the inner film is ruptured. The sealing structure according to claim 1 is characterized in that it also includes: an outer film, the outer film is arranged on the outside of the packaging box at the opening position, the area of the outer film is smaller than the area of the pull tab, and before the sealing cover is opened for the first time, the pull tab is fixedly connected to the outer film; after the sealing cover is opened, the pull tab is separated from the outer film. A production process for a packaging box sealing structure, characterized in that the production process comprises: Step a, punching holes in the composite packaging material used to prepare the packaging box to form an opening; Step b, providing a base at the opening position on the inner side of the corresponding packaging box, wherein the base is provided with a through hole; Step c, providing a sealing cover, wherein the sealing cover has a sealing portion, the sealing portion passes through the opening and is embedded in the through hole, and the sealing portion is tightly engaged with the base to seal the opening; Step d: a pull tab is arranged on the outside of the packaging box, wherein the pull tab is fixedly connected to the sealing cover and is used to drive the sealing cover to open or close the opening. The production process according to claim 13, characterized in that the production process further comprises: Step e: an inner film is arranged below the base, the area of the inner film is larger than the area of the base, the inner film completely covers the base and is fixedly connected to the closing portion and the inner side of the packaging box. The production process according to claim 13 is characterized in that it also includes setting an outer film, setting the outer film at the opening position on the outside of the corresponding packaging box, and the area of the outer film is larger than the area of the opening; or setting the outer film on the composite packaging material on the outside of the corresponding packaging box, and then punching holes in the outer film to form an opening. A packaging box, characterized in that the packaging box is provided with a sealing structure as described in any one of claims 1-12, or the packaging box is provided with a sealing structure prepared by the production process as described in any one of claims 13-15. The packaging box according to claim 16 is characterized in that the packaging box is made of a composite packaging material, and the composite packaging material includes a base layer, a printing layer, a waterproof layer and an innermost layer.