High-strength corrugated carton based on polymer fiber material processing

Abstract

The invention relates to the technical field of packaging materials, in particular to a high-strength corrugated carton based on polymer fiber material processing, and particularly relates to a corrugated carton achieving high strength and high waterproofness through polymer fiber material modification and special structural design. A polymer fiber material is soaked in a sodium hydroxide solution with a certain concentration, hydroxyl groups are introduced to the surface of the fiber, and the interface bonding force between the fiber and base materials such as starch is remarkably improved. According to detection, the bonding strength of the treated fibers and starch is improved by 30%-50%, so that the overall performance of the polymer fiber material layer is enhanced, in addition, compared with traditional corrugated waveforms, the UV composite waveforms are adopted, the compressive strength is improved by 20%-30%, the buffering performance is improved by 15%-20%, external impact force can be dispersed more effectively, and objects in the carton can be protected.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging materials, specifically to a high-strength corrugated paper box processed based on polymer fiber materials, and more particularly to a corrugated paper box that achieves high strength and high waterproofness through polymer fiber material modification and special structural design. Background Art

[0002] Corrugated boxes, as widely used packaging products, play an important role in the transportation and storage of goods. However, traditional corrugated boxes usually use pulp as the main raw material, and have problems such as insufficient strength and poor waterproof performance. They are easily affected by the external environment during transportation and storage, resulting in damage and deformation of the boxes, thereby affecting the quality and safety of the products. With the rapid development of the modern logistics industry, higher requirements are placed on the strength and waterproof performance of corrugated boxes. Although there are attempts to use polymer materials to improve the performance of corrugated boxes in the existing technology, most of them do not perform surface modification on the polymer fibers, resulting in insufficient bonding between the fibers and the matrix material. In addition, there is a lack of systematic optimization of the corrugated structure and the overall structure of the box, making it difficult to achieve a breakthrough improvement in performance.

[0003] For example, utility model patent application number 202322518265.8 discloses an "environmentally friendly, high-strength corrugated cardboard" structure comprising an outer high-strength fiber layer (the polymer type is unspecified) and an inner corrugated paper layer. However, the fiber layer in this patent serves only as a supplementary reinforcement layer and does not completely replace traditional face paper or base paper. Furthermore, the patent does not address the manufacturing process parameters for the polymer fibers.

[0004] In addition, in the utility model patent with patent application number CN202421233931.1, "a high-strength corrugated core paper" is specifically disclosed, which enhances the strength of the corrugated core paper by using inclined support sheets and reinforcing components, but does not involve the application of polymer fibers, and still uses traditional pulp as the base material.

[0005] However, in the above invention patents, polymer fibers are mostly used as auxiliary materials (reinforcement layers, coatings or pulp additives) and have not completely replaced the face paper / base paper.

[0006] Therefore, it is of great practical significance to develop a high-strength corrugated box that combines polymer fiber modification technology with innovative structural design. Summary of the Invention

[0007] The object of the present invention is to provide a high-strength corrugated paper box processed based on polymer fiber materials to solve the problem of limited strength and waterproof performance of traditional corrugated paper boxes mentioned in the above background technology.

[0008] A high-strength corrugated paper box processed based on polymer fiber materials includes a paper box body, which is made of paperboard. The paperboard includes an outer layer, a first reinforcement layer, an intermediate layer, a second reinforcement layer and an inner layer arranged in sequence. The outer layer, the intermediate layer and the inner layer are all polymer fiber material layers. The first reinforcement layer and the second reinforcement layer are both corrugated paper layers. The outer layer and the first reinforcement layer are bonded to form a first surface layer. The intermediate layer and the second reinforcement layer are bonded to form a second surface layer. The first surface layer, the second surface layer and the inner layer are bonded to form paperboard.

[0009] The present invention adopts a five-layer structure of "outer layer + first reinforcement layer + middle layer + second reinforcement layer + inner layer", and forms a synergistic system of "rigid support + flexible enhancement" by alternatingly compounding double corrugated paper layers (first and second reinforcement layers) with polymer fiber layers.

[0010] Interlayer bonding method: The outer layer and the first reinforcement layer, the middle layer and the second reinforcement layer are glued separately to form a "surface layer", and then compounded with the inner layer to ensure the interlayer bonding strength while optimizing the processing technology.

[0011] While existing technologies often use a three-layer structure (face paper + corrugated core + liner), this new invention utilizes a double-corrugated design to increase compressive strength by 40%-60%. The polymer fiber layer completely replaces the traditional pulp face paper and liner, resolving the problem of traditional cartons experiencing a sudden drop in strength after absorbing water (strength retention rate ≥95% in an environment with 90% humidity).

[0012] As an improvement, the specific steps for preparing the carton paperboard by using the polymer fiber material layer are as follows: Step a, preparing raw materials, by weight, 60-80 parts of polymer fiber material, 10-20 parts of starch, 5-10 parts of waterproofing agent, 3-7 parts of reinforcing agent, and 100-150 parts of water; the polymer fiber material is a mixture of one or more of polypropylene fiber, polyester fiber, or polyamide fiber; Step b, fiber dispersion, adding the polymer fiber material to water, stirring at a temperature of 50-70°C and a rotation speed of 200-300 r / min for 10-15 minutes to fully disperse the fibers; Step c, mixing the raw materials, adding starch, waterproofing agent and reinforcing agent to the dispersed fiber solution, stirring at a temperature of 60-80° C. and a rotation speed of 300-400 r / min for 20-30 minutes to obtain a mixed slurry; Step d, papermaking and forming, the mixed slurry is papermade by a papermaking machine, the speed of the papermaking machine is controlled to be 50-80m / min, the vacuum degree of the wire part is -10 to -5kPa, and a wet paper web is obtained; Step e, drying treatment: the wet paper web is sequentially passed through a pre-drying section and a main drying section for drying, the temperature of the pre-drying section is 80-100°C, the drying time is 5-10 minutes, the temperature of the main drying section is 120-150°C, the drying time is 15-20 minutes, to obtain a polymer fiber material layer.

[0013] The axial tensile strength of polymer fiber materials (such as polypropylene, polyester, and aramid fibers) can be 3-8 times that of traditional pulp-based face paper (for example, the tensile strength of a polypropylene fiber layer is ≥150 MPa, while kraft face paper is typically only 20-30 MPa). The high axial load-bearing strength of the outer and inner fiber layers suppresses lateral deformation of the corrugated core paper under pressure. Furthermore, the corrugated core paper's wavy structure, through the "constraint effect" of the polymer fiber layer, prevents localized buckling failure.

[0014] Comparative data: Under the same thickness, the edge pressure strength of the paperboard of the present invention can reach 2.5 times that of traditional corrugated paperboard (traditional A-type corrugated paperboard is 3400N / m, and the edge pressure strength of the paperboard of the present invention is 8000-12000N / m).

[0015] The elongation at break of polymer fibers (e.g., polyester fibers ≥20%) is much higher than that of pulp fibers (≤5%). This allows the cardboard to absorb energy through deformation during impact, reducing brittle fracture. This increases the fatigue life of the cardboard in transport vibration environments by 5-10 times (simulation tests show that after 50 repeated drops, the breakage rate of the cardboard box with this invention is less than 5%, while the breakage rate of traditional cardboard boxes is >60%).

[0016] The water absorption rate of traditional pulp surface paper is greater than 20% (24-hour immersion test), while the water absorption rate of the polymer fiber layer is less than 1%. This feature solves the fatal defects of traditional corrugated boxes in cold chain logistics and humid warehousing scenarios.

[0017] Polymer fibers (such as polypropylene) are significantly more chemically stable to acids, alkalis, and salt solutions than plant fibers. They are suitable for use in highly corrosive environments or for long storage cycles, such as chemicals and pharmaceuticals.

[0018] As an improvement, the polymer fiber material is subjected to surface hydroxylation treatment before use. The treatment method is to place the polymer fiber material in a sodium hydroxide solution with a mass fraction of 5%-10%, soak it at a temperature of 60-80°C for 30-60 minutes, then rinse it with deionized water until it is neutral, and dry it for use.

[0019] Modified with sodium hydroxide solution, hydroxyl groups (-OH) are introduced onto the polymer fiber surface, enhancing the interfacial bonding between the fiber and the matrix (starch, water-repellent). Existing technologies often use unmodified fibers, resulting in low interfacial bonding strength (typically less than 3N / mm). This treatment increases the interfacial shear strength of the fibers to 8-12N / mm, boosting the overall tensile strength of the material by 25%-35%.

[0020] As an improvement, the polymer fiber material is further added with nano-silicon dioxide particles accounting for 0.5%-1% of the total mass of the raw material, and the particle size of the nano-silicon dioxide particles is 50-100 nm.

[0021] Nano-silica particles (50-100 nm) are embedded in the polymer fiber network, inhibiting crack propagation through a "pinning effect" and improving the material's toughness. Existing technologies often add micron-sized fillers (such as calcium carbonate), but this reinforcement effect is limited. The nano-silica of this invention increases the material's elongation at break by 40%-50% while maintaining tensile strength (elongation at break increased from 15% to 22%).

[0022] As an improvement, the waterproofing agent is a graft-modified silicone waterproofing agent, and its preparation method is: silicone monomer and acrylate monomer are grafted copolymerized in a mass ratio of 1: (0.5-1.5) under the action of an initiator, the reaction temperature is 70-90°C, and the reaction time is 2-3h.

[0023] Silicone grafted copolymerization with acrylates combines the hydrophobicity of silicone with the film-forming properties of acrylates, forming a dense waterproof film. Traditional silicone waterproofing agents have poor weather resistance. This grafted product, after 500 hours of UV irradiation, maintains a contact angle of ≥90% (compared to 60%-70% for traditional products) and a water absorption rate of <1% (compared to >5% for traditional products).

[0024] As an improvement, the preparation process of the polymer fiber material layer also includes a surface sizing step, the sizing agent is a mixed solution of starch and polyvinyl alcohol, wherein the mass ratio of starch to polyvinyl alcohol is 1: (0.2-0.5), and the sizing amount is 5-10g / m².

[0025] A starch-PVA blend fills interfiber pores and enhances surface strength and smoothness. Traditional pulp sizing typically uses starch alone. This new method, by adding PVA (20%-50%), increases surface folding resistance by 3-5 times (MIT folding test: from 50 to over 200 times).

[0026] As an improvement, the reinforcing agent is surface-modified glass fiber, and the modification method is to soak the glass fiber in a silane coupling agent solution with a concentration of 2%-5% and a soaking time of 15-30 minutes, and then dry it for use.

[0027] Silane coupling agents form chemical bonds on the glass fiber surface, enhancing its compatibility with the polymer matrix. Unmodified glass fibers tend to agglomerate and have a weak bond with the matrix. The modified glass fibers are evenly dispersed within the matrix, increasing the flexural strength of the composite material by 40%-60% (data from three-point bending tests).

[0028] As an improvement, the corrugated waveforms of the first reinforcement layer and the second reinforcement layer are both UV composite waveforms, and the first reinforcement layer and the second reinforcement layer are made of conventional corrugated paper.

[0029] As an improvement, unlike the manufacture of conventional corrugated paper, after the first surface layer, the second surface layer and the inner layer are glued, the gluing areas of the corrugated waves of the first surface layer and the second surface layer are heated and aged by a flute tip accelerator before entering the double-sided machine for lamination.

[0030] As an improvement, the flute tip accelerator includes a steam spray mechanism for heating the first surface layer and a heat conduction mechanism for heating the second surface layer; The steam spraying mechanism includes a frame and a plurality of steam spraying pipes rotatably arranged on the frame. The steam spraying pipes rotate as the first surface layer is conveyed. When the gluing portion of the corrugated tip on the first surface layer is aligned with the steam spraying pipes, the steam spraying pipes spray steam outward. When the corrugated bottom portion on the first surface layer is aligned with the steam spraying pipes, the steam spraying pipes close the spray holes. The heat conduction mechanism includes a heat conduction box, which is divided into a parallel auxiliary heating layer and a heat conduction heating layer. The auxiliary heating layer is located at the top and the heat conduction heating layer is located at the bottom. The flow direction of water vapor in the auxiliary heating layer is set in the opposite direction to the flow direction of water vapor in the heat conduction heating layer.

[0031] The beneficial effects of the present invention are: (1) The present invention adopts a five-layer composite structure of "outer layer + first reinforcement layer (corrugated paper) + middle layer + second reinforcement layer (corrugated paper) + inner layer". Compared with the traditional three-layer structure (face paper + single corrugated paper + bottom paper), the "rigid and flexible support" synergistic effect of the double corrugated layer increases the edge pressure strength of the cardboard by 60%-80% (test results show that it can reach 10,000-12,000N / m, while traditional cartons only have 5,000-6,000N / m), and the compressive capacity is significantly enhanced. In addition, the first and second reinforcement layers use UV composite corrugated waveforms to increase the flat compression strength of the cardboard by 40% and optimize the cushioning performance by 30%, making it particularly suitable for impact-resistant packaging of precision instruments and heavy equipment; (2) The present invention introduces polar groups (hydroxyl-OH) on the surface of polymer fibers through surface hydroxylation treatment, thereby increasing the interfacial bonding strength between the fibers and the starch matrix by 50% (single fiber pull-out test increased from 5N to 7.5N), avoiding interlayer peeling failure, adding 50-100nm nano-silica particles, and utilizing their "micro-nano pinning effect" to inhibit crack propagation, thereby increasing the tensile strength of the polymer fiber layer by 30% (from 120MPa to 156MPa) and the elongation at break by 25%. The material exhibits the characteristics of "synergistic improvement of strength and toughness". In addition, the glass fiber is modified by a silane coupling agent to solve the compatibility problem between inorganic fibers and organic matrices, so that the reinforcing agent is evenly dispersed in the matrix, the flexural strength of the composite material is increased by 45%, and the fatigue life is extended by more than 3 times. (3) The present invention adopts a silicone-acrylate graft copolymer waterproofing agent, which combines the low surface energy of silicone (hydrophobic angle ≥ 110°) and the film-forming property of acrylate to form a dense waterproof film on the fiber surface, making the water absorption rate of the polymer fiber layer less than 0.8% (24h immersion test), which is significantly better than the traditional pulp layer (water absorption rate > 20%). In addition, the starch-PVA mixed sizing agent is used to fill the fiber pores to form a surface hydrophobic layer, further reducing the surface water absorption rate of the paperboard to below 0.5%. The sizing amount is only 5-10g / m² (traditional pulp sizing requires 20-30g / m²), realizing a double waterproof barrier of "internal hydrophobicity + external protection", which is suitable for high humidity scenarios such as cold chain logistics and humid warehousing; (4) The present invention improves the dispersion uniformity of polymer fibers by 30% (scanning electron microscopy shows that fiber agglomerates are reduced by 60%) by dispersing fibers at 50-70°C and mixing raw materials at 60-80°C, ensuring the consistency of slurry components and avoiding strength fluctuations caused by fiber agglomeration in traditional processes. At the same time, the present invention adopts a gradient drying process of pre-drying (80-100°C) + main drying (120-150°C), which reduces energy consumption by 20% compared with traditional single high-temperature drying. At the same time, it ensures that the moisture content of the fiber layer is ≤6%, avoiding material embrittlement caused by over-drying, and achieving a balance between performance and energy efficiency. (5) The present invention uses a flute tip accelerator to heat and mature the flute tip glued area of the corrugated wave before double-sided lamination after the first surface layer, the second surface layer and the inner layer are coated with glue, so as to promote the pre-gelatinization of the starch paste on the flute tip, thereby achieving the best adhesion of the starch paste. The arc-shaped heating plate of the heat conduction mechanism below contacts the second surface layer for heat conduction. Under the dual action, even if the corrugated cardboard runs at high speed, the first surface layer, the second surface layer and the inner layer can be stably bonded, thereby solving the problems of debonding, poor bonding, unevenness and cracking of the corrugated cardboard. Compared with the solution without using the flute tip accelerator, the bonding strength of the corrugated paper is increased by 31%, further improving the strength of the corrugated cardboard.

[0032] In summary, the present invention has the advantages of high-strength load-bearing, adaptability to humid environments, and diversified functions, and is particularly suitable for the technical field of high-end logistics packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the partial structure of the corrugated paperboard of the present invention; Figure 2 This is a schematic diagram of the layered structure of the corrugated paperboard of the present invention; Figure 3 This is a schematic diagram of the preparation process of the polymer fiber material of the present invention; Figure 4 This is a schematic diagram of the working state of the tip accelerator of the present invention; Figure 5 This is a side structural diagram of the steam injection mechanism of the present invention; Figure 6 This is a schematic diagram of the three-dimensional structure of the steam injection mechanism of the present invention; Figure 7 for Figure 6 A schematic diagram of the structure at center A; Figure 8 This is a schematic diagram of the internal structure of the steam supply pipe of the present invention; Figure 9 This is a schematic diagram of the three-dimensional structure of the steam guide cover of the present invention; Figure 10 This is a schematic diagram of the three-dimensional structure of the protective cover of the present invention; Figure 11 This is a schematic diagram of the working state of the steam injection pipe of the present invention; Figure 12 Schematic diagram of the working state of two adjacent groups of steam injection pipes of the present invention Figure 1 ; Figure 13 Schematic diagram of the working state of two adjacent groups of steam injection pipes of the present invention Figure 2 ; Figure 14 Schematic diagram of the three-dimensional structure of the heat conduction mechanism of the present invention; Figure 15 This is a schematic diagram of the internal structure of the auxiliary heating layer of the present invention; Figure 16 Schematic diagram of the internal layered structure of the heat conduction box of the present invention.

[0034] The reference numerals in the figure are: outer layer 1, first reinforcement layer 2, middle layer 3, second reinforcement layer 4, inner layer 5, first surface layer 10, second surface layer 20, corrugation tip gluing parts 100, 200, corrugation tip accelerator 6, synchronous pulley 601, motor 602, synchronous belt 603, steam injection mechanism 61, frame 611, steam injection pipe 612, spray hole 6121, steam supply pipe 613, steam guide hood 614, hood part 6141, pipe part 6142, steam inlet grille 6143, baffle 6144, protective cover 615, heat conduction mechanism 62, heat conduction box 621, auxiliary heating layer 622, heat conduction heating layer 623, heat conduction fins 624. DETAILED DESCRIPTION

[0035] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0036] The specific embodiments of the present invention are described in detail below. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0037] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In the event of conflict, the definitions in this specification will prevail.

[0038] When this specification uses the prefix "well known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, the objects introduced by the prefix include those conventionally used in the art when the present invention was proposed, but also include those that are not commonly used at present but will become generally recognized in the art to be suitable for similar purposes.

[0039] It should be noted that two or more aspects (or implementation methods) disclosed in the context of this specification can be arbitrarily combined with each other, and the technical solutions (such as methods or systems) thus formed are part of the original disclosure of this specification and also fall within the scope of protection of the present invention.

[0040] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless the weight basis does not conform to the general understanding of those skilled in the art.

[0041] Example 1: like Figure 1-Figure 3 As shown, a high-strength corrugated paper box processed based on polymer fiber material includes a paper box body, which is made of paperboard. The paperboard includes an outer layer 1, a first reinforcement layer 2, an intermediate layer 3, a second reinforcement layer 4 and an inner layer 5 arranged in sequence. The outer layer 1, the intermediate layer 3 and the inner layer 5 are all polymer fiber material layers. The first reinforcement layer 2 and the second reinforcement layer 4 are both corrugated paper layers. The outer layer 1 and the first reinforcement layer 2 are bonded to form a first surface layer 10. The intermediate layer 3 and the second reinforcement layer 4 are bonded to form a second surface layer 20. The first surface layer 10, the second surface layer 20 and the inner layer 5 are bonded to form paperboard.

[0042] The specific steps for preparing the carton paperboard by using the polymer fiber material layer are as follows: Step a, preparing raw materials, by weight, 60-80 parts of polymer fiber material, 10-20 parts of starch, 5-10 parts of waterproofing agent, 3-7 parts of reinforcing agent, and 100-150 parts of water; the polymer fiber material is a mixture of one or more of polypropylene fiber, polyester fiber, or polyamide fiber; Step b, fiber dispersion, adding the polymer fiber material to water, stirring at a temperature of 50-70°C and a rotation speed of 200-300 r / min for 10-15 minutes to fully disperse the fibers; Step c, mixing the raw materials, adding starch, waterproofing agent and reinforcing agent to the dispersed fiber solution, stirring at a temperature of 60-80° C. and a rotation speed of 300-400 r / min for 20-30 minutes to obtain a mixed slurry; Step d, papermaking and forming, the mixed slurry is papermade by a papermaking machine, the speed of the papermaking machine is controlled to be 50-80m / min, the vacuum degree of the wire part is -10 to -5kPa, and a wet paper web is obtained; Step e, drying treatment: the wet paper web is sequentially passed through a pre-drying section and a main drying section for drying, the temperature of the pre-drying section is 80-100°C, the drying time is 5-10 minutes, the temperature of the main drying section is 120-150°C, the drying time is 15-20 minutes, to obtain a polymer fiber material layer.

[0043] Furthermore, the polymer fiber material is subjected to surface hydroxylation treatment before use. The treatment method is to place the polymer fiber material in a sodium hydroxide solution with a mass fraction of 5%-10%, soak it at a temperature of 60-80°C for 30-60 minutes, then rinse it with deionized water until it is neutral, and dry it for use.

[0044] Preferably, the polymer fiber material is further added with nano-silicon dioxide particles accounting for 0.5%-1% of the total mass of the raw material, and the particle size of the nano-silicon dioxide particles is 50-100 nm.

[0045] More preferably, the waterproofing agent is a graft-modified silicone waterproofing agent, and its preparation method is: a silicone monomer and an acrylate monomer are graft-copolymerized in a mass ratio of 1: (0.5-1.5) under the action of an initiator, the reaction temperature is 70-90°C, and the reaction time is 2-3h.

[0046] In addition, the preparation process of the polymer fiber material layer also includes a surface sizing step, and the sizing agent is a mixed solution of starch and polyvinyl alcohol, wherein the mass ratio of starch to polyvinyl alcohol is 1: (0.2-0.5), and the sizing amount is 5-10g / m².

[0047] Furthermore, the reinforcing agent is surface-modified glass fiber, and the modification method is to soak the glass fiber in a silane coupling agent solution with a concentration of 2%-5% for 15-30 minutes, and then dry it for use.

[0048] Example 2: like Figure 4-Figure 16 As shown, the corrugated waveforms of the first reinforcement layer and the second reinforcement layer are both UV composite waveforms.

[0049] During the cardboard processing process, after the first surface layer 10, the second surface layer 20 and the inner layer 5 are glued and before entering the double-sided machine for lamination, the tip accelerator 6 is used to heat and ripen the gluing areas 100, 200 of the corrugated waves of the first surface layer 10 and the second surface layer 20 to improve the viscosity of the starch.

[0050] Specifically, the tip accelerator 6 includes a steam spraying mechanism 61 for heating the first surface layer 10 and a heat conducting mechanism 62 for heating the second surface layer 20; The steam spraying mechanism 61 includes a frame 611 and a plurality of steam spraying pipes 612 rotatably arranged on the frame 611. The steam spraying pipes 612 rotate along with the conveying of the first surface layer 10, and the conveying direction of the first surface layer 10 is consistent with the rotation tangent direction of the steam spraying pipes 612. Every time the steam spraying pipe 612 rotates 60°, the first surface layer 10 is just conveyed a distance of a corrugated waveform. Three groups of parallel spray holes 6121 are arranged axially on the 360° side wall of the steam spraying pipe 612. When the corrugation tip gluing part 100 on the first surface layer 10 is aligned with a group of the steam spraying pipes 612, the steam sprayed from the group of spray holes 6121 on the steam spraying pipe 612 just covers the corrugation tip gluing part 100 (high-temperature steam, separated by a water vapor separation tank). When the corrugation bottom part on the first surface layer 10 is aligned with the steam spraying pipe 612, the steam spraying pipe 612 just rotates to close the spray holes 6121. The heat conduction mechanism 62 includes a heat conduction box 621, which is divided into a parallel auxiliary heating layer 622 and a heat conduction heating layer 623. The auxiliary heating layer 622 is located at the top, and the heat conduction heating layer 623 is located at the bottom. The flow direction of water vapor in the auxiliary heating layer 622 is set in the opposite direction to the flow direction of water vapor in the heat conduction heating layer 623.

[0051] Specifically, each group of steam injection pipes 612 is provided with a synchronous pulley 601. Through the synchronous belt 603, all the steam injection pipes 612 rotate synchronously, and the synchronous pulley 601 located at the outermost edge is installed and connected to the motor 602. After the motor is started, it drives all the steam injection pipes 612 to rotate.

[0052] It should also be specifically explained that a steam supply pipe 613 is provided on one side of the frame 611. The inlet end of the steam injection pipe 612 is located in the steam supply pipe 613. The inlet end of the steam injection pipe 612 is provided with a steam guide cover 614 through an interference fit. The steam guide cover 614 consists of a cover portion 6141 and a circular tubular pipe portion 6142. The cover portion 6141 is located outside the inlet end of the steam injection pipe 612, and the pipe portion 6142 is inserted into the interior of the steam injection pipe 612. The cover portion 6141 is divided into three parts. There are three steam inlet grilles 6143 corresponding to the three groups of nozzles 6121, three sealed baffles 6144, the baffles 6144 and the steam inlet grilles 6143 are arranged alternately, and a protective cover 615 is also provided on the outside of each steam guide cover 614, the protective cover 615 is fixedly connected to the frame 611, and the protective cover 615 is used to close the remaining air inlet grilles 6143. When the steam inlet grilles 6143 are aligned with the steam flow direction, the steam is introduced into the steam injection pipe 612. A group of steam injection pipes 612 are provided with a plurality of air inlet grilles 6143. When the spray hole 6121 is arranged facing the gluing part 100 at the corrugated tip, there is a set of steam inlet grilles 6143 arranged facing the steam flow direction. When the baffle 6144 faces the steam flow direction, the steam is blocked outside and directed to the next set of steam spray pipes 612. Along the steam flow direction of the steam supply pipe 613, the depth of the steam guide cover 614 on the steam spray pipe 612 inserted into the steam supply pipe 613 is gradually increased, so that when the steam spray pipe 612 sprays steam, the steam supply can be guaranteed. The steam jet pipes 612 should be balanced, and two adjacent steam jet pipes 612 form a group. When one of the two steam jet pipes 612 is heating the flute tip gluing section 100, the steam jet pipes 612 of the other group are just aimed at the flute bottom and do not work. When the flute tip gluing section 100 gradually moves away from the coverage distance of the steam jet pipes 612 of the group, the group of spray holes 6121 on the next group of steam jet pipes 612 just connects, so that the flute tip gluing section 100 is always heated by steam jets. Furthermore, when the steam jet pipes 612 of one group of steam jet pipes 612 are heating the flute tip gluing section 100, the spray holes 6121 on the steam jet pipes 612 of the group will rotate along with the transportation of the flute tip gluing section 100, extending the heating time of the spray holes 6121 on the flute tip gluing section 100 and maximizing steam utilization.

[0053] It is further explained that in the heat conduction mechanism, S-shaped flow channels are formed inside the auxiliary heating layer 622 and the thermal conductive heating layer 623 through partitions, and inside the flow channel, there are heat conduction fins 624 with the upper part located in the auxiliary heating layer 622 and the lower part located in the thermal conductive heating layer 623. The heat conduction fins 624 transfer the heat of the auxiliary heating layer 622 to the thermal conductive heating layer 623, and the heat of the auxiliary heating layer 622 is used to balance the thermal conductive heating layer 623, which nearly solves the problem of unbalanced heat at the beginning and end of the heat conduction mechanism due to continuous heat consumption in the flow path, thereby improving the thermal conductivity balance of the heat conduction mechanism.

[0054] Preparation Example 1: Prepare raw materials: 60 parts of polypropylene fiber, 10 parts of starch, 5 parts of silicone waterproofing agent, 3 parts of glass fiber, and 100 parts of water; Fiber dispersion: Add polypropylene fibers into water and stir at 50°C and 200 r / min for 10 minutes to fully disperse the fibers. Mixing raw materials: Add starch, silicone waterproofing agent and glass fiber to the dispersed fiber solution, stir at a temperature of 60°C and a speed of 300 r / min for 20 minutes to obtain a mixed slurry; Papermaking: The mixed slurry is passed through a papermaking machine to form a wet paper web. The speed of the papermaking machine is controlled at 50 m / min and the vacuum degree of the wire is -10 kPa to obtain a wet paper web. Drying treatment: The wet paper web is sequentially dried through a pre-drying section and a main drying section. The temperature of the pre-drying section is 80°C, the drying time is 5 minutes, and the temperature of the main drying section is 120°C, the drying time is 15 minutes, to obtain a polymer fiber material layer.

[0055] The prepared polymer fiber layer is combined with the corrugated paper layer in the embodiment and the flute tip accelerator in Example 2 to form a five-layer composite structure of "outer layer + first reinforcement layer (corrugated paper) + middle layer + second reinforcement layer (corrugated paper) + inner layer" for preparing corrugated paperboard.

[0056] Preparation Example 2: The difference from Preparation Example 1 is that the raw materials are prepared as follows: 70 parts of polyester fiber, 15 parts of starch, 8 parts of acrylic waterproofing agent, 5 parts of carbon fiber, and 120 parts of water; Fiber dispersion: Add polyester fiber into water and stir at 60℃ and 250r / min for 12 minutes to fully disperse the fiber. Mixing raw materials: Add starch, acrylic waterproofing agent and carbon fiber to the dispersed fiber solution, stir at a temperature of 70°C and a speed of 350 r / min for 25 minutes to obtain a mixed slurry; Papermaking: The mixed slurry is passed through a papermaking machine to form a wet paper web. The speed of the papermaking machine is controlled at 65 m / min and the vacuum degree of the wire is -7.5 kPa to obtain a wet paper web. Drying treatment: The wet paper web is sequentially dried through a pre-drying section and a main drying section. The temperature of the pre-drying section is 90°C, the drying time is 7 minutes, and the temperature of the main drying section is 135°C, the drying time is 17 minutes, to obtain a polymer fiber material layer.

[0057] Preparation Example 3: The difference from Preparation Example 1 is that the raw materials are prepared as follows: 80 parts of polyamide fiber, 20 parts of starch, 10 parts of silicone waterproofing agent, 7 parts of glass fiber, and 150 parts of water; Fiber dispersion: Add polyamide fiber to water and stir at 70°C and 300 r / min for 15 minutes to fully disperse the fiber; Mixing raw materials: Add starch, silicone waterproofing agent and glass fiber to the dispersed fiber solution, stir at a temperature of 80°C and a speed of 400 r / min for 30 minutes to obtain a mixed slurry; Papermaking: The mixed slurry is passed through a papermaking machine to form a wet paper web. The speed of the papermaking machine is controlled at 80 m / min and the vacuum degree of the wire is -5 kPa to obtain a wet paper web. Drying treatment: The wet paper web is sequentially dried through a pre-drying section and a main drying section. The temperature of the pre-drying section is 100°C, the drying time is 10 minutes, and the temperature of the main drying section is 150°C, the drying time is 20 minutes, to obtain a polymer fiber material layer.

[0058] Preparation Example 4: The difference from Preparation Example 3 is that the polyamide fiber is surface hydroxylated (immersed in 8% sodium hydroxide solution at 70° C. for 45 minutes) and 0.8% nano-silica particles are added.

[0059] Preparation parameters: fiber dispersion temperature 65℃, stirring speed 250r / min; mixed raw material temperature 75℃, stirring speed 350r / min; papermaking speed 65m / min, web vacuum -7.5kPa; pre-drying 95℃×8min, main drying 140℃×18min.

[0060] Preparation Example 5: The difference from Preparation Example 3 is that, in the preparation of the waterproofing agent, silicone and acrylate are graft copolymerized in a mass ratio of 1:1 (80° C., 2.5 hours), and the reinforcing agent is a silane coupling agent-modified glass fiber.

[0061] Comparative Example 1: Unhydroxylated polypropylene fibers were used, and the remaining raw materials and preparation parameters were the same as those in Preparation Example 1.

[0062] Comparative Example 2: The first reinforcement layer and the second reinforcement layer use traditional U-shaped corrugated paper, and the rest of the structure is the same as that of Preparation Example 3.

[0063] Comparison Example 3: No nano-silica particles were added to the outer layer and the inner layer, and the rest was the same as Preparation Example 4.

[0064] Comparative Example 4: The prepared polymer fiber layer is combined with the corrugated paper layer to form a five-layer composite structure of "outer layer + first reinforcement layer (corrugated paper) + middle layer + second reinforcement layer (corrugated paper) + inner layer" corrugated paperboard for preparing corrugated paper boxes. The difference is that the flute tip accelerator in Example 2 is not used to heat the first surface layer and the second surface layer. The rest is the same as Preparation Example 1.

[0065] Test Example 1: The corrugated paperboards prepared in Preparation Examples 1 to 5 and Comparative Examples 1 to 4 were tested for reference compressive strength / edge compressive strength using TAPPIT 804, for adhesive strength using ASTM D3330, and for waterproof performance using the Kobelco method + water repellency. The test results are shown in Table 1 below: Table 1 By comparing Preparation Example 1 to Preparation Example 3, as the polymer fiber content increases (60→80 parts), the compressive strength increases from 85kN to 98kN, and the edge compression strength increases from 8200N / m to 9500N / m, reflecting the improvement of basic strength by optimizing the raw material ratio.

[0066] By comparing Preparation Example 4 and Preparation Example 5, after introducing hydroxylated fiber + nano-silica or grafted waterproofing agent + modified reinforcing agent, the strength exceeded 100kN and 10,000N / m. Among them, due to the "micro-nano enhancement effect" of nanoparticles, the edge compression strength of Preparation Example 4 was increased by 13.7% compared with Preparation Example 3, verifying the synergistic enhancement effect of surface modification and nanotechnology.

[0067] From comparative example 1, it can be seen that the non-hydroxylation treatment leads to weak fiber-matrix bonding, and the strength is reduced by 27% compared with example 1, which proves that surface hydroxylation is a key step in improving interface bonding.

[0068] From comparative example 2, we can see that the traditional U-shaped corrugated paper (without UV composite corrugation) reduces the edge pressure strength by 24%, which shows the contribution of composite corrugation design to structural strength.

[0069] It can be seen from Preparation Examples 4 to 5 that the bonding strength is ≥9N / 25mm, which is significantly higher than the basic example (≤7.8N / 25mm). This is due to the silane coupling agent modified reinforcing agent + flute tip accelerator heating and ripening. The latter improves the adhesiveness of starch (Comparative Example 4 did not use an accelerator, and the bonding strength decreased by 31%), proving the key role of process innovation in interlayer bonding.

[0070] Comparative Example 4: Without using the flute tip accelerator, the bonding strength is only 5.5N / 25mm, which is lower than 6.5N / 25mm in Example 1, verifying that heating and aging the flute tip can improve the bonding efficiency.

[0071] It can be seen from Preparation Example 4-Preparation Example 5 that the water repellency reaches R8-R9 level, and the water absorption rate is less than 5g / m², which is better than the basic example (R5-R7, water absorption rate 6.8-8.2g / m²). The core benefits from the double waterproof barrier of the grafted modified waterproofing agent (Preparation Example 5) and nano-silica (Preparation Example 4). The former is hydrophobic through the molecular layer, and the latter fills the pores to reduce water seepage.

[0072] From Comparative Example 1, it can be seen that the unhydroxylated fiber leads to uneven dispersion of the waterproofing agent, with a water repellency of only R3 and a water absorption rate exceeding 12 g / m², indicating that fiber surface treatment is a prerequisite for waterproof performance.

[0073] As can be seen from Example 3, without adding nanoparticles, the water absorption rate increased by 33% compared with Example 4, proving that nanoparticles improve the density.

[0074] In summary, material modification (hydroxylated fiber, nano-silica, grafted waterproofing agent) and structural design (double UV corrugated layer, corrugation tip accelerator) form a triple reinforcement, and through surface polarization (hydroxylation), nano-reinforcement (silica), and molecular grafting (waterproofing agent), the three key problems of fiber-matrix bonding strength, porosity, and surface energy are solved; mechanical support is provided by the double corrugated layer (UV composite waveform), and the corrugation tip accelerator improves the bonding efficiency, forming a synergistic system of "material strengthening + structural stabilization".

[0075] Furthermore, the lack of a single technology (such as non-hydroxylation, traditional corrugation, no nanoparticles, and no heat aging) all leads to a significant decline in performance (strength ↓20%-30%, waterproof ↓40%-60%), proving that the technical features of the various claims of the present invention are inextricably linked and indispensable.

[0076] The core indicators of Preparation Example 4-Preparation Example 5 reached edge compression strength > 10000N / m (traditional carton ≤ 5000N / m), meeting the packaging needs of heavy equipment; water repellency R8-R9 level (international cold chain standard R6 level), water absorption rate < 5g / m² (traditional pulp paperboard > 20g / m²), suitable for high humidity environment; interlayer bonding strength ≥ 9N / 25mm (traditional starch glue < 5N / 25mm), avoiding delamination failure during transportation.

[0077] In addition, the tip accelerator increases bonding strength by 38% while reducing glue usage by 15%, achieving a balance between high performance and low cost.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-strength corrugated paper box made of polymer fiber material, comprising a paper box body, characterized in that: The carton body is made of cardboard, which includes an outer layer, a first reinforcement layer, a middle layer, a second reinforcement layer and an inner layer arranged in sequence. The outer layer, the middle layer and the inner layer are all polymer fiber material layers. The first reinforcement layer and the second reinforcement layer are both corrugated paper layers. The outer layer and the first reinforcement layer are bonded together to form a first surface layer. The middle layer and the second reinforcement layer are bonded together to form a second surface layer. The first surface layer, the second surface layer and the inner layer are bonded together to form cardboard.

2. The high-strength corrugated paper box made of polymer fiber material according to claim 1, characterized in that: The specific steps for preparing the carton paperboard by using the polymer fiber material layer are as follows: Step a, preparing raw materials, by weight, 60-80 parts of polymer fiber material, 10-20 parts of starch, 5-10 parts of waterproofing agent, 3-7 parts of reinforcing agent, and 100-150 parts of water; the polymer fiber material is a mixture of one or more of polypropylene fiber, polyester fiber, or polyamide fiber; Step b, fiber dispersion, adding the polymer fiber material to water, stirring at a temperature of 50-70°C and a rotation speed of 200-300 r / min for 10-15 minutes to fully disperse the fibers; Step c, mixing the raw materials, adding starch, waterproofing agent and reinforcing agent to the dispersed fiber solution, stirring at a temperature of 60-80° C. and a rotation speed of 300-400 r / min for 20-30 minutes to obtain a mixed slurry; Step d, papermaking and forming, the mixed slurry is papermade by a papermaking machine, the speed of the papermaking machine is controlled to be 50-80m / min, the vacuum degree of the wire part is -10 to -5kPa, and a wet paper web is obtained; Step e, drying treatment: the wet paper web is sequentially passed through a pre-drying section and a main drying section for drying, the temperature of the pre-drying section is 80-100°C, the drying time is 5-10 minutes, the temperature of the main drying section is 120-150°C, the drying time is 15-20 minutes, to obtain a polymer fiber material layer.

3. The high-strength corrugated paper box made of polymer fiber material according to claim 2, characterized in that: The polymer fiber material is subjected to surface hydroxylation treatment before use. The treatment method is to place the polymer fiber material in a sodium hydroxide solution with a mass fraction of 5%-10%, soak it at a temperature of 60-80°C for 30-60 minutes, then rinse it with deionized water until it is neutral, and dry it for use.

4. The high-strength corrugated paper box made of polymer fiber material according to claim 2, characterized in that: The polymer fiber material is further added with nano-silicon dioxide particles accounting for 0.5%-1% of the total mass of the raw material, and the particle size of the nano-silicon dioxide particles is 50-100nm.

5. The high-strength corrugated paper box made of polymer fiber material according to claim 2, characterized in that: The waterproofing agent is a graft-modified organic silicon waterproofing agent, and its preparation method is: organic silicon monomer and acrylate monomer are subjected to graft copolymerization reaction in a mass ratio of 1: (0.5-1.5) under the action of an initiator, the reaction temperature is 70-90°C, and the reaction time is 2-3h.

6. The high-strength corrugated paper box made of polymer fiber material according to claim 2, characterized in that: The preparation process of the polymer fiber material layer also includes a surface sizing step, wherein the sizing agent is a mixed solution of starch and polyvinyl alcohol, wherein the mass ratio of starch to polyvinyl alcohol is 1:(0.2-0.5), and the sizing amount is 5-10g / m².

7. The high-strength corrugated paper box made of polymer fiber material according to claim 2, characterized in that: The reinforcing agent is surface-modified glass fiber, and the modification method is to soak the glass fiber in a silane coupling agent solution with a concentration of 2%-5% for 15-30 minutes, and then dry it for use.

8. The high-strength corrugated paper box made of polymer fiber material according to claim 1, characterized in that: The corrugated waveforms of the first reinforcement layer and the second reinforcement layer are both UV composite waveforms.

9. The high-strength corrugated paper box made of polymer fiber material according to claim 1, characterized in that: After the first surface layer, the second surface layer and the inner layer are coated with glue and before entering the double-sided machine for compounding, the gluing parts of the corrugated waves of the first surface layer and the second surface layer are heated and cured by a flute tip accelerator.

10. The high-strength corrugated paper box made of polymer fiber material according to claim 9, characterized in that: The tip accelerator includes a steam spray mechanism for heating the first surface layer and a heat conduction mechanism for heating the second surface layer; The steam spraying mechanism includes a frame and a plurality of steam spraying pipes rotatably arranged on the frame. The steam spraying pipes rotate as the first surface layer is conveyed. When the gluing portion of the corrugated tip on the first surface layer is aligned with the steam spraying pipes, the steam spraying pipes spray steam outward. When the corrugated bottom portion on the first surface layer is aligned with the steam spraying pipes, the steam spraying pipes close the spray holes. The heat conduction mechanism includes a heat conduction box, which is divided into a parallel auxiliary heating layer and a heat conduction heating layer. The auxiliary heating layer is located at the top and the heat conduction heating layer is located at the bottom. The flow direction of water vapor in the auxiliary heating layer is set in the opposite direction to the flow direction of water vapor in the heat conduction heating layer.

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