Industrial green circulating corrugated board

Abstract

The utility model relates to the technical field of corrugated boards, in particular to an industrial green circulating corrugated board, which mainly solves the problems that the strength and the buffering performance of the corrugated board in the prior art cannot be achieved at the same time, and the energy-saving and environment-friendly effects are poor, and comprises a corrugated board body, the corrugated paper body comprises first surface paper, second surface paper, third surface paper, first core paper and second core paper, the first core paper is compounded on the upper surface of the first surface paper, the first core paper is of a wave structure, so that the first core paper is provided with first wave crests and first wave troughs which are distributed in a staggered mode in the longitudinal direction, and the second core paper is compounded on the upper surface of the first core paper. The second core paper is of a wave structure, so that the second core paper is provided with second wave crests and second wave troughs which are distributed in a staggered mode in the longitudinal direction, the transverse sides of the upper surfaces of the first wave crests are compounded to the transverse sides of the lower surfaces of the second wave crests, the second surface paper is compounded to the upper surface of the second core paper, and grooves are formed in the second surface paper in a pressed mode at intervals in the longitudinal direction.

Description

Technical Field

[0001] This utility model relates to the field of corrugated cardboard technology, and in particular to an industrial green recyclable corrugated cardboard. Background Technology

[0002] Corrugated cardboard, also known as corrugated paperboard, is made of at least one layer of corrugated paper and one layer of cardboard bonded together. It has good elasticity and extensibility. Due to its light weight, low price, and high structural strength, it has become widely used and promoted for packaging a wide variety of goods.

[0003] However, in the traditional production process of corrugated cardboard, the linerboard and corrugated paper are bonded together with adhesive to fix them. The strength of the bond affects the strength of the corrugated paper and mainly depends on the amount of adhesive used. That is, when it is suitable for heavy packaging, more adhesive needs to be applied, and the hardness is relatively high, resulting in poor cushioning effect. At the same time, the use of adhesive affects the recycling of corrugated cardboard, reduces the recycling rate of corrugated cardboard, and has poor energy-saving and environmental protection effects. Utility Model Content

[0004] Therefore, in view of the above problems, this utility model provides an industrial green recyclable corrugated cardboard, which mainly solves the problem that the strength and cushioning performance of existing corrugated cardboard cannot be achieved at the same time, and the energy-saving and environmental protection effects are poor.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An industrial green recyclable corrugated cardboard includes a corrugated cardboard body, defined as extending longitudinally along the length direction of the corrugated cardboard body and transversely along the width direction of the corrugated cardboard body. The corrugated cardboard body includes a first face paper, a second face paper, a third face paper, a first core paper, and a second core paper. The first core paper is laminated to the upper surface of the first face paper and has a wavy structure, such that the first core paper has a first wave peak and a first wave trough staggered along the longitudinal direction. The second core paper is laminated to the upper surface of the first core paper and has a wavy structure, such that the second core paper has a second wave peak and a second wave trough staggered along the longitudinal direction. One transverse side of the upper surface of the first wave peak is laminated to one transverse side of the lower surface of the second wave peak. The second face paper is laminated to the upper surface of the second core paper. Grooves are pressed at intervals along the longitudinal direction on the second face paper, and the lower surface of the grooves of the second face paper is laminated to the other transverse side of the upper surface of the second wave peak. The third face paper is laminated to the upper surface of the second face paper by a starch-based adhesive, and the starch-based adhesive fills the grooves.

[0007] Furthermore, the amplitude of the first peak is not greater than the amplitude of the second peak, and the amplitude of the first trough is not greater than the amplitude of the second trough.

[0008] Furthermore, the amplitude of the first peak is equal to the amplitude of the second peak, and the amplitude of the first trough is equal to the amplitude of the second trough.

[0009] Furthermore, the tangent angle at the point where the first and second peaks overlap is 45° to 70°.

[0010] By adopting the aforementioned technical solution, the beneficial effects of this utility model are as follows: This industrial green recyclable corrugated cardboard, through the setting of longitudinally staggered double-layer corrugated core paper, namely the first core paper and the second core paper, utilizes the staggered composite structure of its crests and troughs to form a multi-directional supporting mechanical network. Furthermore, the transverse side of the crest of the first core paper is composite with the transverse side of the crest of the second core paper, and the groove of the second face paper is composite with the other side of the crest of the second core paper, so that the stress is effectively dispersed in both the longitudinal and transverse directions. This not only enhances the compressive strength, but also retains the buffering and energy absorption characteristics through the elastic deformation of the corrugated structure, solving the problem that the strength and buffering performance of traditional single-layer core paper cannot be simultaneously achieved. The grooved design of the second face paper, combined with the filling of starch-based adhesive, forms an "embedded" bonding structure, increasing the contact area between the second face paper and the second core paper by 40% to 50%. The adhesive penetrates into the internal pores of the core paper corrugations, significantly improving interlayer peel strength and avoiding the defects of easy delamination in traditional planar composites, ensuring the overall structural stability. The use of all-starch-based adhesive to replace traditional petroleum-based adhesives achieves a biodegradable and pollution-free green composite process. Experimental verification shows that this adhesive reduces the impact of corrugated cardboard recycling and resizing rate to less than 2%, and reduces VOC emissions during production by more than 90%, meeting the needs of industrial circular economy development. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view of the corrugated paper in an embodiment of this utility model;

[0012] Figure 2 This is a schematic diagram of the adhesive preparation device in an embodiment of this utility model;

[0013] Figure 3 This is a cross-sectional structural diagram of the main tank in an embodiment of this utility model. Detailed Implementation

[0014] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0015] The embodiment of this utility model is as follows:

[0016] refer to Figure 1As shown, an industrial green recyclable corrugated cardboard includes a corrugated cardboard body, defined as extending longitudinally along the length direction and transversely along the width direction. The corrugated cardboard body includes a first face paper 101, a second face paper 102, a third face paper 103, a first core paper 104, and a second core paper 105. The first core paper 104 is laminated to the upper surface of the first face paper 101 and has a wavy structure, such that the first core paper 104 has first peaks 114 and first troughs 124 staggered along the longitudinal direction. The second core paper 105 is laminated to the upper surface of the first core paper 104. The second core paper 105 has a wave-like structure, with second peaks 115 and second troughs 125 staggered along the longitudinal direction. The lateral side of the upper surface of the first peak 114 is laminated to the lateral side of the lower surface of the second peak 115. The second face paper 102 is laminated to the upper surface of the second core paper 105. Grooves 112 are pressed at intervals along the longitudinal direction on the second face paper 102. The lower surface of the grooves 112 of the second face paper 102 is laminated to the other lateral side of the upper surface of the second peak 115. The third face paper 103 is laminated to the upper surface of the second face paper 102 by a starch-based adhesive 106, which fills the grooves 112.

[0017] This industrial green recyclable corrugated cardboard utilizes a longitudinally staggered double-layer corrugated core paper structure, namely the first core paper 104 and the second core paper 105, to form a multi-directional support mechanical network through the staggered composite structure of its crests and troughs. Furthermore, the first crest 114 of the first core paper 104 is composited on one side with the second crest 115 of the second core paper 105 on the other side, and the groove 112 of the second face paper 102 is composited on the other side with the second crest 115 of the second core paper 105. This effectively disperses stress both longitudinally and laterally, enhancing compressive strength while retaining cushioning and energy absorption characteristics through the elastic deformation of the corrugated structure. This solves the problem of the incompatibility between strength and cushioning performance in traditional single-layer core paper. The groove 112 design of the second face paper 102, combined with the filling of starch-based adhesive 106, forms an "embedded" bonding structure, increasing the contact area between the second face paper 102 and the second core paper 105 by 40% to 50%. The adhesive penetrates into the internal pores of the core paper crest, significantly improving the interlayer peel strength and avoiding the defects of easy delamination in traditional planar composites, ensuring the overall structural stability. The use of all-starch-based adhesive to replace traditional petroleum-based adhesives achieves a biodegradable and pollution-free green composite process. Experimental verification shows that the adhesive reduces the impact of the resizing rate of corrugated cardboard to less than 2%, and reduces VOC emissions during the production process by more than 90%, meeting the needs of industrial circular economy development.

[0018] refer to Figure 2 and Figure 3As shown, an industrial green recyclable corrugated cardboard production process includes the following steps:

[0019] 1) Cardboard pretreatment:

[0020] a. Using 80% to 100% recycled waste paper as raw material, preferably 85%, the recycled paper pulp is produced after being crushed, screened and deinked by a pulper;

[0021] b. Add 5% to 10% biomass fiber to the recycled pulp, preferably 8%, and then grind it using a pulper;

[0022] c. The pulp from step b is pumped into the pulping machine, where it is heated, pressurized, and dewatered during rotation to squeeze out excess water and form paperboard.

[0023] d. The cardboard from step c is fed into the forming machine and flattened inside the forming machine. Then it is dried in the dryer to evaporate the moisture and make the core paper and face paper.

[0024] 2) Preparation of starch-based adhesive:

[0025] e. Using an adhesive preparation device, mix corn starch with a fineness greater than 58 mesh and water at a ratio of 1:6, stir for 30 minutes to form a uniform slurry, then add 5% sulfuric acid and treat at room temperature for 24 hours to remove impurities.

[0026] f. Add 0.2% nickel sulfate and react at 55°C for 2 hours, then oxidize with 3% hydrogen peroxide at 45°C for 40 minutes to obtain a light yellow adhesive.

[0027] g. Slowly add 12% sodium hydroxide solution, heat to 65°C, stir for 40 minutes until a semi-transparent paste is formed, and control the temperature at 57°C.

[0028] h. Add 0.5% borax, crosslink for 40 minutes, and then add 0.08% defoamer, 2% urea and 8% calcium carbonate in sequence;

[0029] i. Add calcium carbonate or hydrochloric acid to adjust the pH value to 8.5, and add 1.3% plant extract. After cooling to room temperature, filter and package.

[0030] 3) Corrugated paper forming: The temperature of the corrugated roll is less than 120℃, and the composite pressure gradient is controlled so that the adhesive penetration rate is not greater than 3% when the core paper and the face paper are laminated. The composite pressure gradient is 30N / cm²~50N / cm².

[0031] 4) Introduce the product from step 3 into a negative pressure drying chamber, control the drying temperature at 95℃, and the pressure range at -20KPa;

[0032] 5) Waste recycling: Collect production waste, crush it, and then use membrane separation technology to recover adhesive components from the wastewater for reuse in paperboard pretreatment.

[0033] This industrial green circular corrugated cardboard production process uses 80%–100% recycled waste paper raw materials, significantly reducing the consumption of virgin wood. Combined with 5%–10% straw and other biomass fibers, it achieves resource utilization of waste, reducing environmental pollution. Excess moisture is squeezed out through a heating, pressurizing, and hydrophobic process, increasing the cardboard density and reducing subsequent drying energy consumption. Furthermore, based on starch, a high-strength, low-permeability environmentally friendly adhesive is formed through nickel sulfate catalytic oxidation and borax cross-linking reaction, replacing traditional formaldehyde-based adhesives. At a low temperature of 80℃–100℃ combined with a negative pressure environment (-10kPa–30kPa), moisture evaporation is accelerated while preventing cardboard deformation, resulting in significant energy savings. Wastewater is separated and the adhesive components are recovered, and waste is crushed and reused, achieving near-zero emissions throughout the entire process. This demonstrates excellent energy-saving and environmental protection effects, aligning with industrial green circularity.

[0034] In this embodiment, the biomass fiber is made by crushing straw to below 200 mesh, which greatly increases the specific surface area of ​​the fiber. When interwoven with recycled pulp, it forms a dense network structure, which improves the compressive strength of the core paper by 10% to 15% and reduces the energy consumption of straw pretreatment.

[0035] In this embodiment, the plant extract is tannic acid. As a natural polyphenol compound, tannic acid can enhance the crosslinking density of adhesives and improve the water resistance of the adhesive layer by 20% to 30%. Its antibacterial properties inhibit mold growth on cardboard and extend the storage period.

[0036] In this embodiment, 0.7% nano-silica is added in step e above. The nano-silica forms a three-dimensional network structure in the adhesive, which increases the mechanical strength of the adhesive layer by 15% to 20%, and at the same time improves the interfacial bonding force between the adhesive and the paper fiber through the surface hydroxyl effect.

[0037] Furthermore, in step 3) above, the composite pressure gradient control process is as follows: the temperature in the composite workshop is controlled at 20℃ and the humidity at 62%. The starch-based adhesive is applied at 35 N / cm² and maintained at 80℃ to wet the surface of the core paper for 4 seconds to prevent excessive penetration into the corrugated gaps. Then, the pressure is increased to 50 N / cm² and the temperature is maintained at 100℃. The starch-based adhesive is evenly distributed by the pressure gradient, while limiting the penetration depth. The staged pressure control combined with precise temperature and humidity control keeps the adhesive penetration depth stable within the range of 0.1 to 0.3 mm, avoiding "insufficient adhesive areas" caused by excessive penetration of adhesive into the corrugated gaps, and ensuring an interlayer peel strength ≥1.5 kN / m.

[0038] Furthermore, in step 3) above, the corrugated paper includes a first face paper 101, a second face paper 102, a third face paper 103, a first core paper 104, and a second core paper 105, and the corrugated paper forming process includes:

[0039] j. The first sheet 101 is unwound and conveyed, and adhesive is sprayed on the upper surface of the first sheet 101. The direction of conveying the first sheet 101 is defined as the longitudinal direction, and the direction of the width of the first sheet 101 is defined as the transverse direction.

[0040] k. The first core paper 104 is unwound and conveyed, and a wave structure is formed by the corrugated roll. The first core paper 104 is then laminated onto the first face paper 101. The first core paper 104 has first peaks 114 and first troughs 124 that are staggered along the longitudinal direction.

[0041] 1. Apply adhesive to the upper surface of the first core paper 104, unwind and convey the second core paper 105, and form a wave structure through the corrugated roller. Then, laminate the second core paper 105 onto the first core paper 104. The second core paper 105 has second peaks 115 and second troughs 125 that are staggered along the longitudinal direction. The transverse side of the upper surface of the first peak 114 is laminated onto the transverse side of the lower surface of the second peak 115.

[0042] m. Apply adhesive to the upper surface of the second core paper 105, unwind and convey the second face paper 102, and press grooves 112 at intervals along the longitudinal direction on the second face paper 102, and laminate the second face paper 102 onto the second core paper 105, and the lower surface of the grooves 112 of the second face paper 102 is laminated to the other side of the transverse side of the upper surface of the second crest 115.

[0043] n. Spray adhesive onto the upper surface of the second paper 102 and fill the groove 112 with starch-based adhesive 106;

[0044] o. Unwind and convey the third paper 103, and laminate it onto the upper surface of the second paper 102.

[0045] By interlocking the crests and troughs laterally, the longitudinal and transverse compressive strength of the cardboard is balanced, and the cushioning performance is improved by 25% to 40%, making it particularly suitable for heavy-duty packaging scenarios.

[0046] Furthermore, the amplitude of the first peak 114 is not greater than the amplitude of the second peak 115, preferably, the amplitude of the first peak 114 is equal to the amplitude of the second peak 115, and the amplitude of the first trough 124 is not greater than the amplitude of the second trough 125, preferably, the amplitude of the first trough 124 is equal to the amplitude of the second trough 125, forming a progressive support structure, dispersing external impact force, improving edge crush strength, and reducing the risk of core paper breakage.

[0047] Furthermore, the tangent angle at the point where the first peak 114 and the second peak 124 are combined is 45° to 70°, preferably 60°, which optimizes the stress transmission path, reduces the concentration of interlayer shear stress, and enables the paperboard to achieve a burst strength of more than 1500 kPa, which is 18% to 22% higher than that of the traditional right-angle composite structure.

[0048] In this embodiment, the adhesive preparation device includes a main tank 201, a starch tank 202, a first additive tank 203, a second additive tank 204, a drive motor 205, a stirring rod 206, stirring blades 207, a fast water addition pipe 208, a slow water addition pipe 209, a heating pipe 210, a starch inlet pipe 211, a first inlet pipe 212, a second inlet pipe 213, a discharge pipe 214, an overflow pipe 215, a suction pipe 216, a drain pipe 217, a liquid pump 218, and a first spiral... The system includes an extrusion pump 219 and a second spiral extrusion pump 220. The main tank 201 has a separate stirring chamber 301 and a heat preservation chamber 302. The heating pipe 210 is connected to the heat preservation chamber 302. The main tank 201, which is connected to the stirring chamber 301, is equipped with a water inlet 401, a starch outlet 402, a first feeding port 403, a second feeding port 404, a drain port 405, a suction port 406, and an overflow port 407. The fast water inlet pipe 208 and the slow water inlet pipe 209 are both connected to the water inlet 401. 01 Connection, the starch feed pipe 211 is connected to the starch inlet 402, the starch tank 202 is connected to the starch feed pipe 211 via the first screw extrusion pump 219, the first additive tank 203 is connected to the first feeding port 403 via the first feed pipe 212, the second additive tank 204 is connected to the second feeding port 404 via the second feed pipe 213 and the second screw extrusion pump 220, one end of the extraction pipe 216 is connected to the extraction port 406, and the overflow pipe 21 One end of the 5 is connected to the overflow port 407, one end of the drain pipe 217 is connected to the drain port 405, the other end of the overflow pipe 215 and the material extraction pipe 216 is connected to the discharge pipe 214, the discharge pipe 214 is connected to the drain pipe 217 through the liquid pump 218, the stirring rod 206 is rotatably mounted on the main tank 201, the drive motor 205 is connected to the outer end of the stirring rod 206, and the stirring blades 207 are mounted on the stirring rod 206 and distributed in the stirring chamber 301.

[0049] By connecting the insulation chamber to the heating pipe, precise control of the adhesive reaction temperature during stirring is achieved (±1℃ deviation), avoiding the problems of localized overheating or uneven starch gelatinization caused by direct heating in traditional single-chamber structures. The design of the insulation chamber 302 surrounding the stirring chamber 301 reduces heat loss, saving 15% to 20% more energy than conventional electrically heated stirring tanks. Initial rapid water addition enables the starch granules to swell quickly, while subsequent slow water addition promotes stable adhesive viscosity, improving the starch / water mixing uniformity by more than 30% and preventing clumping. A screw extrusion pump is used to transport starch and additives, such as nickel sulfate and hydrogen peroxide, with a metering accuracy of ±0.5%, which is significantly higher than traditional gravity-driven methods. The feeding method reduces raw material waste by 12%–15%, making it particularly suitable for the precise addition of trace components such as nano-silica. The overflow port 407 discharges excess adhesive to the discharge pipe 214 in real time, which, together with the liquid pump 218, enables online circulation filtration of the adhesive, improving the removal efficiency of reaction byproducts (such as oxidative degradation impurities) by 40% and ensuring the purity of the adhesive. Through the combination of membrane separation and recovery and precise feeding by the screw pump, the comprehensive utilization rate of adhesive raw materials reaches 98.5%, and the production cost is reduced by 18%–22%. The closed-loop design of the overflow pipe 215 and the sewage pipe 217 enables 100% recycling and reuse of wastewater / waste adhesive, which meets the standards of green industrial production.

[0050] In this embodiment, the starch-based adhesive can also be a starch-based adhesive mixture disclosed in patent announcement number 1283738C, which is the prior art.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0052] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0053] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] Although the present 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 present invention without departing from the spirit and scope of the present invention as defined in the appended claims, and all such changes shall be within the scope of protection of the present invention.

Claims

1. An industrial green recycled corrugated paperboard, characterized by: The corrugated board body includes a first face paper, a second face paper, a third face paper, a first core paper, and a second core paper, the first core paper is compounded on an upper surface of the first face paper, the first core paper has a wave structure, such that the first core paper has first wave crests and first wave troughs staggered along a longitudinal direction, the second core paper is compounded on an upper surface of the first core paper, the second core paper has a wave structure, such that the second core paper has second wave crests and second wave troughs staggered along the longitudinal direction, a lateral side of an upper surface of the first wave crest is compounded on a lateral side of a lower surface of the second wave crest, the second face paper is compounded on an upper surface of the second core paper, the second face paper has grooves pressed thereon along the longitudinal direction at intervals, a lower surface of the groove of the second face paper is compounded on a lateral side of an upper surface of the second wave crest, the third face paper is compounded on an upper surface of the second face paper by means of a starch-based adhesive, and the starch-based adhesive is filled in the groove.

2. The industrial green recycled corrugated paperboard according to claim 1, characterized in that: An amplitude of the first wave crest is not greater than an amplitude of the second wave crest, and an amplitude of the first wave trough is not greater than an amplitude of the second wave trough.

3. The industrial green recycled corrugated paperboard according to claim 2, characterized in that: The amplitude of the first wave crest is equal to the amplitude of the second wave crest, and the amplitude of the first wave trough is equal to the amplitude of the second wave trough.

4. The industrial green recycled corrugated paperboard according to any one of claims 1 to 3, characterized in that: A tangent angle at a compound position of the first wave crest and the second wave crest is 45°-70°.

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