A cigarette packet, a composite cardboard and a method for manufacturing the same

Abstract

The application discloses a cigarette packet, a composite cardboard and a preparation method thereof. The cigarette packet comprises a surface paper layer, a first adhesive layer and a bottom paper layer, and further comprises a plurality of water vapor absorbing units. Each water vapor absorbing unit is arranged in a non-continuous periodic array and comprises a local moisture absorption buffer layer, a water vapor permeable functional layer and a second adhesive layer. The local moisture absorption buffer layer is arranged on the lower side of the first adhesive layer. The water vapor permeable functional layer is arranged on the lower side of the local moisture absorption buffer layer, so that water vapor can be permeated in one direction, and the water vapor permeation rate is limited at the same time, thereby forming damping control on the water vapor transmission flux. The second adhesive layer is arranged between the water vapor permeable functional layer and the bottom paper layer, and the second adhesive layer is configured to be weakly bonded and has water vapor permeability. The bottom paper layer has a microporous area allowing water vapor to pass through, so that the water vapor regulation mode of moisture release-moisture absorption-humidity balance adjustment can be realized through the water vapor absorbing units, and the controlled transmission of water vapor in the cigarette packet and the humidity fluctuation buffering adjustment can be realized.

Description

Technical Field

[0001] This invention relates to the field of printing and packaging technology, and in particular to a cigarette pack, composite cardboard, and a method for preparing the same. Background Technology

[0002] Currently, tobacco packaging mainly relies on high-barrier composite materials or adding desiccants inside the packaging to control humidity and thus achieve moisture-proof function.

[0003] Many cigarette packs use composite cardboard with PE film, aluminum foil, or high-barrier coating to block external moisture from entering. Although this can slow down the intrusion of external moisture, internal moisture inevitably accumulates during the opening, transportation, and storage of cigarette packs. Especially in high-humidity environments, the moisture inside the cigarette pack is difficult to release in time, which can easily lead to the cigarettes becoming damp, moldy, or having a reduced smoking performance.

[0004] In addition, some cigarette packs reduce local humidity by adding desiccants inside, but this increases the structural complexity and production cost of the cigarette pack. At the same time, it has problems such as low assembly efficiency and poor positional stability on high-speed packaging lines. Furthermore, its moisture absorption capacity is limited, making it difficult to achieve long-term and balanced humidity regulation. There may also be problems of tobacco over-drying due to continuous dehumidification. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a cigarette pack, composite cardboard, and a method for preparing the same. This not only maintains the structural integrity of the cigarette pack but also achieves a moisture control method through a moisture absorption unit, which involves slow release, adsorption, and humidity balance regulation. This enables controlled transmission of moisture within the cigarette pack and buffering of humidity fluctuations.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows: This invention provides a unidirectional moisture-absorbing composite cardboard, comprising a face paper layer and a back paper layer arranged vertically, and a first adhesive layer located between the face paper layer and the back paper layer. It also includes a plurality of moisture-absorbing units disposed between the first adhesive layer and the back paper layer. The moisture-absorbing units are arranged in a discontinuous periodic array and include a localized moisture-absorbing buffer layer, a moisture-permeable functional layer, and a second adhesive layer. The localized moisture-absorbing buffer layer is disposed on the side of the first adhesive layer opposite to the face paper layer. The moisture-permeable functional layer covers the side of the localized moisture-absorbing buffer layer opposite to the first adhesive layer, allowing moisture to permeate unidirectionally while simultaneously limiting the moisture permeation rate to dampen the moisture transport flux. The second adhesive layer is disposed between the moisture-permeable functional layer and the back paper layer, and is configured with weak adhesion and moisture permeability. The back paper layer has microporous regions corresponding to each moisture-absorbing unit, and each microporous region has a plurality of micropores that allow moisture to pass through.

[0007] Furthermore, the localized moisture-absorbing buffer layer is configured to absorb moisture only when the ambient relative humidity is higher than a preset threshold.

[0008] Furthermore, the localized moisture-absorbing buffer layer is coated onto the first adhesive layer using an amplitude-modulated mesh method, with a coverage of 70-90%, while ensuring the exposed interface of the first adhesive layer.

[0009] Furthermore, the water vapor permeable functional layer is a polyethylene film with unidirectional water vapor permeability, and only allows water vapor to pass through the micropores of the base paper layer, and then sequentially through the second adhesive layer and the water vapor permeable functional layer, and finally be absorbed by the local moisture-absorbing buffer layer.

[0010] Furthermore, the area of ​​the water-permeable functional layer is larger than the area of ​​the corresponding local moisture-absorbing buffer layer, and ensures that the four sides of the water-permeable functional layer are respectively bonded to the first adhesive layer.

[0011] Furthermore, the second adhesive layer is coated onto the water vapor permeable functional layer by means of amplitude modulation and meshing, and its coverage is 20-30%.

[0012] Furthermore, the micropores are laser-perforated with a diameter of 30–80 μm; the micropores are arranged in a regular periodic array with a pore density of 100–500 pores / cm²; the pore diameter and pore density of the micropores are matched to ensure that the total open area of ​​the micropores is not greater than 2%.

[0013] Furthermore, the face paper layer serves as the main support structure; the first adhesive layer is fully coated on the lower surface of the face paper layer, and the base paper layer is laminated to the face paper layer provided with moisture-absorbing units through the first adhesive layer and the second adhesive layer; and / or, a decorative pattern layer is provided on the side of the face paper layer opposite to the first adhesive layer.

[0014] This invention provides a cigarette pack with moisture-absorbing function, which is made of the aforementioned composite cardboard that can absorb moisture in one direction.

[0015] This invention provides a method for preparing a unidirectional moisture-absorbing composite cardboard, comprising the following steps: S1, preparing a face paper layer, wherein the face paper layer is coated cardboard of 100-300 g / m²; S2, applying a first adhesive layer to the lower surface of the face paper layer by roll coating, and then drying to form a continuous adhesive interface; S3, applying a localized moisture-absorbing buffer layer to the lower surface of the first adhesive layer by resin stencil or spray coating, and then drying to form a discontinuous periodic array distribution; S4, laminating a moisture-permeable functional layer onto the lower surface of the localized moisture-absorbing buffer layer, and then laminating it onto the lower surface of the first adhesive layer by lamination; S5, applying a second adhesive layer to the lower surface of the unidirectional moisture-absorbing buffer layer by resin stencil or spray coating. The lower surface of the moisture-absorbing functional layer is then dried to form a moisture-absorbing unit layer; the moisture-absorbing unit layer includes the face paper layer and moisture-absorbing units disposed on the face paper layer; S6, a base paper layer is prepared, and the base paper layer is 100-150g / m² coated paper; a regular periodic array of micropores is processed on the base paper layer by laser perforation process, and the micropore structure is consistent with the array distribution of the local moisture-absorbing buffer layer; S7, the base paper layer in S6 and the moisture-absorbing unit layer in S5 are bonded and composited by the second adhesive layer, and the upper surface of the base paper layer and the lower surface of the face paper layer are bonded and composited by the first adhesive layer, finally forming a multi-layer composite paperboard.

[0016] The technical solution provided by this invention has the following beneficial effects: This invention utilizes a discontinuous, periodically arrayed localized moisture-absorbing buffer layer and a moisture-permeable functional layer with moisture-damping properties to achieve a moisture control method involving slow release, moisture adsorption, and humidity balance regulation. This enables controlled moisture transport and humidity fluctuation buffering within the tobacco pack, avoiding the problem of excessive tobacco drying caused by direct exposure or continuous dehumidification of traditional moisture-absorbing materials. When relative humidity increases, it can temporarily adsorb excess moisture, thereby maintaining relative stability of the humidity inside the tobacco pack. Furthermore, this invention does not affect the structural integrity of the tobacco pack or the molding process, and is compatible with existing lamination, die-cutting, and molding processes, demonstrating good industrial feasibility and application value. Attached Figure Description

[0017] Figure 1 The diagram shown is a composite paperboard structure capable of unidirectional moisture absorption in the embodiment. Figure 2 The diagram shown is a schematic of the coating structure of the local moisture-absorbing buffer layer in the embodiment. Figure 3 The diagram shown is a schematic diagram of the coating structure of the second adhesive layer in the embodiment; Figures 4 to 7 The diagram shows the different distributions of the microporous region within the cigarette pack in the embodiment.

[0018] Explanation of reference numerals in the attached figures: 1: Face paper layer; 2: First adhesive layer; 3: Bottom paper layer; 31: Microporous area; 4: Local moisture-absorbing buffer layer; 5: Water vapor permeable functional layer; 6: Second adhesive layer; 7: Decorative pattern layer; 100: Water vapor absorbing unit; 200: Cigarette box body; 201: Box body; 202: Flip-top. Detailed Implementation

[0019] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0020] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0021] Reference Figures 1 to 7 This embodiment provides a cigarette pack with moisture-absorbing function, including a cigarette box body 200. The cigarette box body 200 includes a box body 201 and a flip-top cover 202 connected to the box body 201. The cigarette box body 200 is made of composite cardboard that can absorb moisture in one direction.

[0022] like Figure 1 As shown, the composite cardboard of this embodiment includes a face paper layer 1 and a back paper layer 3 arranged on top of each other, a first adhesive layer 2 located between the face paper layer 1 and the back paper layer 3, and a plurality of moisture-absorbing units 100 disposed between the first adhesive layer 2 and the back paper layer 3. The back paper layer 3 has microporous areas 31 corresponding to each moisture-absorbing unit 100, and each microporous area 31 has a plurality of micropores that allow moisture to pass through. The microporous areas 31 are located inside the cigarette box body 200. Of course, the upper surface of the face paper layer 1 facing away from the first adhesive layer 2 may be provided with a decorative pattern layer 7 to enhance the overall aesthetics.

[0023] Each moisture-absorbing unit 100 is arranged in a non-continuous periodic array, and each moisture-absorbing unit 100 includes a local moisture-absorbing buffer layer 4, a moisture-permeable functional layer 5, and a second adhesive layer 6 arranged sequentially from top to bottom.

[0024] like Figure 2 As shown, each local moisture-absorbing buffer layer 4 is disposed on the lower side of the first adhesive layer 2 away from the face paper layer 1.

[0025] Each water-permeable functional layer 5 covers the corresponding local moisture-absorbing buffer layer 4 and is located away from the lower side of the first adhesive layer 2.

[0026] like Figure 3As shown, each of the second adhesive layers 6 is configured to have weak adhesion (i.e., low interfacial adhesion) and water vapor permeability. Each of the second adhesive layers 6 is coated on the underside of the corresponding water vapor permeable functional layer 5 away from the local moisture-absorbing buffer layer 4 by means of amplitude modulation and screen coating, and its coverage is 20-30%. At this time, the second adhesive layer 6 is located between the water vapor permeable functional layer 5 and the backing paper layer 3.

[0027] In this embodiment, the face paper layer 1 is the main support structure of the composite cardboard. The first adhesive layer 2 is fully coated on the lower surface of the face paper layer 1. The bottom paper layer 3 is attached and laminated to the face paper layer 1, which is provided with each moisture-absorbing unit 100, through the first adhesive layer 2 and the second adhesive layer 6, so as to finally form the composite cardboard of this embodiment.

[0028] More specifically, the microporous area 31 is disposed on the side wall of the housing 201 near the end of the flip cover 202, and this side wall is directly connected to the flip cover 202. For example... Figure 4 As shown, the microporous area 31 is disposed on the side wall of the flip cover 202, and this side wall is directly connected to the box body 201. Figure 5 As shown, the microporous region 31 is disposed on the top wall of the flip cover 202. (As indicated...) Figure 6 or Figure 7 As shown, microporous areas 31 are provided on the side walls of the box body 201 and the top wall of the flip cover 202. The microporous areas 31 are located at the upper end of the cigarette box body 200, and this area is the main area for external moisture intrusion. The area, location, and number of microporous areas 31 can be adjusted according to the environmental humidity conditions of different regions. Of course, Figures 4 to 7 The microporous area 31 shown is for demonstration purposes only and does not mean that other areas cannot be set. Furthermore, the sidewalls and topwalls covered by the microporous area 31 must be strictly controlled within the range of the indentation line and cannot be set on the indentation line or have the indentation line pass through the microporous area 31.

[0029] Each micropore on the base paper layer 3 is laser-perforated with a pore size of 30–80 μm. This ensures a diffused water vapor transport environment inside the tobacco pack, preventing rapid absorption of water vapor and maintaining a stable micro-humidity balance. The micropores are arranged in a regular periodic array, forming a uniform water vapor exchange interface in the micropore region 31 of the base paper layer 3, which helps improve the uniformity of internal humidity control. The pore density is 100–500 pores / cm², ensuring the overall strength of the paper remains stable. While ensuring moisture permeability, the mechanical strength of the base paper layer is not significantly reduced. The pore size and pore density of each micropore are matched to ensure that the total open porosity of the micropores is no more than 2%. This ensures that the humidity balance of the microenvironment inside the tobacco pack is dominated by the local moisture-absorbing buffer layer 4, with the micropores merely serving as channels for internal water vapor exchange. This effectively prevents the tobacco pack from becoming overly dry in low-humidity environments, thus maintaining the synergistic regulatory effect of the multi-layer structure of the water vapor absorption unit 100. Overall, the internal microenvironment of the cigarette pack is defined by the pore size D, pore density N, and total open area η of the micropores created by laser perforation (a simple estimation formula is N≤η / (π)). D 2 (N∈[100,500]), allowing water vapor transport to proceed in a diffusion manner, and working in conjunction with the water vapor permeable functional layer 5 and the local moisture-absorbing buffer layer 4 to achieve a dual reduction in the amplitude and rate of humidity change inside the tobacco pack.

[0030] More specifically, each water vapor permeable functional layer 5 is a polyethylene film with unidirectional water vapor permeability. Water vapor is only allowed to pass through the micropores of the base paper layer 3, and then sequentially through each second adhesive layer 6 and the corresponding water vapor permeable functional layer 5, and finally be absorbed by each local moisture-absorbing buffer layer 4. In this way, water vapor can pass through each water vapor permeable functional layer 5 in one direction, while limiting the water vapor permeability rate, so as to form a damping control on the water vapor transmission flux, thereby realizing the controlled transmission of water vapor in the cigarette pack.

[0031] Furthermore, each localized moisture-absorbing buffer layer 4 is configured to absorb moisture only when the relative humidity of the environment is higher than a preset threshold. Therefore, when each localized moisture-absorbing buffer layer 4 uses a humidity-buffered moisture-absorbing material, its moisture absorption behavior is significantly enhanced when the relative humidity of the environment is higher than the preset threshold; while when the relative humidity of the environment is lower than the preset threshold, it basically does not absorb moisture. This achieves buffering and regulation of humidity fluctuations inside the tobacco pack. The humidity-buffered moisture-absorbing material in this embodiment mainly uses any one or a combination of modified calcium silicate, modified bentonite, and modified aluminosilicate. In this embodiment, modified calcium silicate is used as an example. Its basic component is a CaSiO3 / CaO-SiO2 system, which is amorphous or weakly crystalline calcium silicate. It forms a nano- to micron-level interconnected pore structure inside. It has no free salt, no organic migrations, does not release dust (i.e., embedded in the paper layer), and does not adsorb aroma molecules, thereby ensuring the safety of tobacco and odor. Modified calcium silicate is made into particles with a diameter of 5-30 μm and formulated into an aqueous adhesive for co-coating. The aqueous adhesive used is an adhesive system that is permeable to water vapor. The ratio of moisture-absorbing material to adhesive (solid content) is 1:0.3 to 1:1, and the coating amount (dry basis) is 3-15 g / m².

[0032] In summary, this embodiment utilizes a discontinuous, periodically arrayed localized moisture-absorbing buffer layer 4 and a moisture-permeable functional layer 5 with moisture-permeable damping effect to achieve a moisture control method of slow release, moisture adsorption, and humidity balance regulation. This enables controlled transmission of moisture within the tobacco pack and buffering of humidity fluctuations. This avoids the problem of excessive tobacco drying caused by direct exposure or continuous dehumidification of traditional moisture-absorbing materials. When the relative humidity increases, it can temporarily adsorb excess moisture, thereby maintaining the relative stability of the humidity inside the tobacco pack. Furthermore, this embodiment does not affect the structural integrity of the tobacco pack or the molding process, and is compatible with existing lamination, die-cutting, and molding processes, demonstrating good industrial feasibility and application value.

[0033] Of course, in other embodiments, the water vapor permeable functional layer 5 can also be made of other thin film materials with one-way water vapor permeability; the micropores on the backing paper layer 3 can also be made by mechanical perforation, which will not be described in detail here.

[0034] In a further preferred embodiment, each local moisture-absorbing buffer layer 4 is coated onto the first adhesive layer 2 using an amplitude-modulated mesh coating method, with a coverage rate of 70-90%. At the same time, the exposed interface of the first adhesive layer 2 is ensured so that the moisture-permeable functional layer 5 can bond to the face paper layer 1 through the exposed interface of the first adhesive layer 2. This avoids the formation of obvious bulges between the moisture-permeable functional layer 5 and the local moisture-absorbing buffer layer 4, or even between the moisture-permeable functional layer 5 and the face paper layer 1, which would affect the performance of the composite cardboard and thus the overall functionality and aesthetics of the cigarette pack.

[0035] Further preferred, such as Figure 1As shown, the area of ​​each water-permeable functional layer 5 is larger than the area of ​​the corresponding local moisture-absorbing buffer layer 4, and ensures that the four sides of each water-permeable functional layer 5 are respectively bonded to the first adhesive layer 2, thereby ensuring that each water-permeable functional layer 5 is firmly bonded by the first adhesive layer 2, and the relative position with each local moisture-absorbing buffer layer 4 is also relatively fixed.

[0036] In addition, this embodiment also provides a method for preparing composite cardboard, which can be used to prepare composite cardboard that can absorb moisture in one direction, specifically including the following steps: Step S1: Prepare face paper layer 1, which is coated paper of 100-300g / m².

[0037] Step S2: The first adhesive layer 2 is coated onto the lower surface of the face paper layer 1 by roller coating, and then dried to form a continuous adhesive interface.

[0038] In step S3, each local moisture-absorbing buffer layer 4 is coated onto the lower surface of the first adhesive layer 2 by means of resin plate or spraying, and then dried to form a discontinuous periodic array distribution.

[0039] Step S4: Each water-permeable functional layer 5 is laminated onto the lower surface of the corresponding local moisture-absorbing buffer layer 4, and then laminated onto the lower surface of the first adhesive layer 2 by lamination.

[0040] Step S5: Each second adhesive layer 6 is coated onto the lower surface of the corresponding water vapor permeable functional layer 5 by means of resin plate or spraying, and then dried to form each moisture-absorbing unit layer.

[0041] Step S6: Prepare the base paper layer 3, which is a coated cardstock of 100-150 g / m². A regular periodic array of micropores is processed on the base paper layer 3 by laser perforation, and the micropore structure is consistent with the array distribution of the local moisture-absorbing buffer layer 4.

[0042] In step S7, the base paper layer 3 and the moisture-absorbing unit layer are bonded and laminated through the second adhesive layer 6, and the upper surface of the base paper layer 3 and the lower surface of the face paper layer 1 are bonded and laminated through the first adhesive layer 2, thus forming a multi-layer composite cardboard.

[0043] After the composite cardboard is prepared, it is then subjected to positioning printing, die-cutting, creasing and forming processes to form the cigarette pack of this embodiment. The microporous area 31 is set on the side wall of the cigarette pack.

[0044] When the cigarette pack is in daily use, the bottom paper layer 3 with microporous area 31, as well as the various local moisture-absorbing buffer layers 4 and water vapor permeable functional layers 5 work together in a sealed state to ensure that the cigarette pack can temporarily absorb and buffer excess water vapor when the relative humidity inside the cigarette pack increases, thereby achieving a stable relative humidity inside the cigarette pack.

[0045] Furthermore, compared to existing technologies that only improve air permeability through micropores, external moisture can directly enter the cigarette pack, which exacerbates the risk of internal dampness and makes it difficult to meet the requirements of controlled moisture permeability for cigarette packs. Therefore, the composite cardboard in this embodiment has the advantages of high structural integration and controllable moisture regulation capabilities, and is applicable to existing cigarette pack forming processes. Thus, this embodiment can solve the problems of passive humidity control, single function, and insufficient process adaptability in existing technologies.

[0046] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A unidirectional moisture-absorbing composite cardboard, comprising a face paper layer and a back paper layer disposed on top of each other, and a first adhesive layer located between the face paper layer and the back paper layer, characterized in that: It also includes multiple moisture-absorbing units disposed between the first adhesive layer and the backing paper layer; The moisture-absorbing units are arranged in a discontinuous periodic array and include a local moisture-absorbing buffer layer, a moisture-permeable functional layer, and a second adhesive layer. The local moisture-absorbing buffer layer is disposed on the side of the first adhesive layer opposite to the face paper layer. The moisture-permeable functional layer covers the side of the local moisture-absorbing buffer layer opposite to the first adhesive layer, so that moisture can pass through in one direction while limiting the moisture permeation rate, thereby damping the moisture transport flux. The second adhesive layer is disposed between the moisture-permeable functional layer and the back paper layer, and the second adhesive layer is configured to have weak adhesion and moisture permeability. The base paper layer has microporous regions corresponding to each water vapor absorption unit, and the microporous regions have multiple micropores that allow water vapor to pass through.

2. The unidirectional moisture-absorbing composite cardboard according to claim 1, characterized in that: The localized moisture-absorbing buffer layer is configured to absorb moisture only when the relative humidity of the environment is higher than a preset threshold.

3. The unidirectional moisture-absorbing composite cardboard according to claim 1, characterized in that: The localized moisture-absorbing buffer layer is coated onto the first adhesive layer using an amplitude modulation and meshing method, with a coverage of 70-90%, while ensuring the exposed interface of the first adhesive layer.

4. The unidirectional moisture-absorbing composite cardboard according to claim 1, characterized in that: The water vapor permeable functional layer is a polyethylene film with one-way water vapor permeability. It only allows water vapor to pass through the micropores of the base paper layer, and then sequentially through the second adhesive layer and the water vapor permeable functional layer, and finally be absorbed by the local moisture-absorbing buffer layer.

5. The unidirectional moisture-absorbing composite cardboard according to claim 1, characterized in that: The area of ​​the water-permeable functional layer is larger than the area of ​​the corresponding local moisture-absorbing buffer layer, and the four sides of the water-permeable functional layer are respectively bonded to the first adhesive layer.

6. The unidirectional moisture-absorbing composite cardboard according to any one of claims 1-5, characterized in that: The second adhesive layer is coated onto the water vapor permeable functional layer by means of amplitude modulation and mesh reinforcement, and its coverage is 20-30%.

7. The unidirectional moisture-absorbing composite cardboard according to any one of claims 1-5, characterized in that: The micropores are laser-perforated with a diameter of 30–80 μm; the micropores are arranged in a regular periodic array with a pore density of 100–500 per cm²; the pore diameter and pore density of the micropores are matched to ensure that the total open area of ​​the micropores is not greater than 2%.

8. The unidirectional moisture-absorbing composite cardboard according to any one of claims 1-5, characterized in that: The face paper layer serves as the main support structure; the first adhesive layer is fully coated on the lower surface of the face paper layer, and the base paper layer is bonded to the face paper layer with the moisture-absorbing unit through the first adhesive layer and the second adhesive layer; and / or, a decorative pattern layer is provided on the side of the face paper layer opposite to the first adhesive layer.

9. A tobacco pack with moisture-absorbing function, characterized in that: It is made of composite cardboard that is capable of unidirectional moisture absorption as described in any one of claims 1-8.

10. A method for preparing a unidirectional moisture-absorbing composite cardboard, characterized in that, Includes the following steps: S1, Prepare a face paper layer, wherein the face paper layer is coated paper with a weight of 100-300 g / m²; S2, the first adhesive layer is applied to the lower surface of the face paper layer by roller coating, and then dried to form a continuous adhesive interface; S3, the local moisture-absorbing buffer layer is coated onto the lower surface of the first adhesive layer by means of resin plate or spraying, and then dried to form a discontinuous periodic array distribution; S4, the water vapor permeable functional layer is laminated onto the lower surface of the local moisture-absorbing buffer layer, and then laminated onto the lower surface of the first adhesive layer. S5, the second adhesive layer is applied to the lower surface of the moisture-permeable functional layer by means of resin plate or spraying, and then dried to form a moisture-absorbing unit layer; the moisture-absorbing unit layer includes the face paper layer and moisture-absorbing units disposed on the face paper layer. S6, Prepare a base paper layer, wherein the base paper layer is coated paper with a weight of 100-150 g / m²; process a regular periodic array of micropores on the base paper layer by laser perforation process, wherein the micropore structure is consistent with the array distribution of the local moisture-absorbing buffer layer; S7, the bottom paper layer in S6 and the moisture-absorbing unit layer in S5 are bonded and laminated through the second adhesive layer, and the upper surface of the bottom paper layer and the lower surface of the face paper layer are bonded and laminated through the first adhesive layer, finally forming a multi-layer composite cardboard.

11. The method for preparing the unidirectional moisture-absorbing composite cardboard according to claim 10, characterized in that: The localized moisture-absorbing buffer layer is configured to absorb moisture only when the relative humidity of the environment is higher than a preset threshold.

12. The method for preparing the unidirectional moisture-absorbing composite cardboard according to claim 10 or 11, characterized in that: The water vapor permeable functional layer is a polyethylene film with one-way water vapor permeability. It only allows water vapor to pass through the micropores of the base paper layer, and then sequentially through the second adhesive layer and the water vapor permeable functional layer, and finally be absorbed by the local moisture-absorbing buffer layer.

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