Environment-friendly wear-resistant corrugated board and preparation method thereof

Abstract

The invention relates to the technical field of packaging materials, in particular to an environment-friendly wear-resistant corrugated board and a preparation method thereof. The corrugated board comprises an upper wear-resistant surface paper, an upper adhesive layer, a corrugated core layer with a trapezoidal wave structure, a lower adhesive layer and a lower wear-resistant surface paper, the surface paper takes recycled waste paper pulp as a main raw material, the adhesive layer is a modified starch-based environment-friendly adhesive, and a multi-layer composite wear-resistant coating is arranged on the outer surface of the surface paper. Grading the waste paper pulp to obtain long and short fiber pulp; adding auxiliaries such as nano cellulose into the long fiber pulp to prepare enhanced paper pulp, making paper into surface paper, and pressing the short fiber pulp into a trapezoidal corrugated core through a corrugated roller; preparing a coating consisting of a bio-based epoxy resin bottom layer, a polyurethane-graphene composite middle layer and a silicon dioxide reinforced acrylate outer layer, and sequentially coating the surface paper with the coating; and finally, bonding the layers by using a modified starch adhesive, and carrying out hot press molding. The packaging material is suitable for packaging scenes with high requirements for strength, wear resistance and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to an environmentally friendly and wear-resistant corrugated cardboard and its preparation method. Background Technology

[0002] As a core material in modern packaging and logistics systems, the performance of corrugated cardboard directly affects commodity protection, transportation efficiency, and resource consumption. With the rapid development of e-commerce, high-end manufacturing, and green supply chains, the market has placed high demands on corrugated cardboard for high strength, long lifespan, and environmental friendliness. However, existing technologies have encountered significant bottlenecks in balancing and breaking through these two key dimensions, especially in the synergistic improvement of abrasion resistance and environmental friendliness, where there are many inherent defects.

[0003] Traditional corrugated cardboard surfaces are primarily composed of cellulose fibers, which are inherently soft and porous. During distribution, they are easily worn down by friction and scratches, resulting in blurred or even damaged printed graphics. This not only severely impacts brand image and information recognition but also directly diminishes the packaging's reusability. To address this issue, existing technologies generally employ surface coating with resin coatings. For example, Chinese patent CN110105859A discloses a wear-resistant coating based on water-based polyurethane and modified corrugated pulp. While this technology improves abrasion resistance to some extent, its coating design is often relatively simple, focusing on physical shielding without addressing the chemical bonding between the coating and the hydrophilic paper base. Under complex stress or temperature and humidity changes, it is prone to interfacial peeling, cracking, or localized aggravated wear. Another Chinese patent, CN119266027A, demonstrates a composite coating constructed from polyvinylidene fluoride, graphene oxide, and various inorganic fillers to achieve high wear resistance and high strength. This solution introduces high-performance materials, but the coating system is complex, and there may be compatibility and stress matching issues between its multi-layered structure. More importantly, this type of technical solution relies heavily on synthetic polymer resins and fine inorganic fillers, whose raw materials are non-renewable, and whose preparation consumes a lot of energy. Furthermore, the coating itself is difficult to effectively peel off or degrade during the paperboard recycling process, which essentially brings new obstacles to the environmentally friendly recycling of end products.

[0004] Existing corrugated cardboard technology has significant shortcomings in synergistically improving abrasion resistance and environmental friendliness. It is difficult to achieve durable abrasion resistance through simple coatings. Furthermore, due to the non-renewable nature of the materials, high energy consumption in production, and recycling barriers, it is difficult to meet the requirements of a green supply chain. As a result, traditional corrugated cardboard is prone to problems such as surface wear, information ambiguity, and structural failure in high-frequency use scenarios. Therefore, it is possible to improve abrasion resistance while achieving renewable raw materials, low-energy production, and high recycling rates. This is essential for ensuring the safe transportation of goods and extending the life cycle of packaging. Summary of the Invention

[0005] Based on the problems existing in the above-mentioned background technology, the present invention proposes an environmentally friendly wear-resistant corrugated cardboard. The corrugated cardboard includes, from top to bottom, an upper wear-resistant linerboard, an upper adhesive layer, a corrugated core layer, a lower adhesive layer, and a lower wear-resistant linerboard. The upper and lower wear-resistant linerboards are made primarily from recycled waste paper pulp. The corrugated core layer has a trapezoidal corrugated structure, which improves compressive strength and stability while ensuring cushioning performance. The upper and lower adhesive layers are made of modified starch-based environmentally friendly adhesives, which have good adhesion and flexibility. The outer surfaces of the upper and lower wear-resistant linerboards are also coated with a composite wear-resistant coating.

[0006] Preferably, the upper and lower abrasion-resistant paper also contain a nano-reinforcing agent, which is nanocellulose.

[0007] Preferably, the wave height of the trapezoidal wave structure is 3.0–4.0 mm and the wave distance is 6.0–8.0 mm.

[0008] Preferably, the modified starch-based environmentally friendly adhesive is prepared as follows: corn starch and water are mixed at a mass ratio of 1:(4-6), heated to 80-90℃ for gelatinization, and then 0.3-0.7% borax and 0.8-1.2% glycerol equivalent to the mass of corn starch are added. The mixture is stirred for 15 minutes and then cooled to room temperature to obtain the final product.

[0009] Preferably, the composite wear-resistant coating comprises, from the inside out, a base coating, an intermediate coating, and an outer coating. The base coating is a bio-based epoxy resin layer, which enhances the adhesion between the coating and the paper substrate. The intermediate coating is a polyurethane-graphene composite layer, which provides high wear resistance and toughness. The outer coating is a silica nanoparticle reinforcing layer, which improves surface hardness and scratch resistance.

[0010] Preferably, the preparation process of the composite wear-resistant coating is as follows: bio-based epoxy resin and curing agent are mixed at a mass ratio of 10:1, and silane coupling agent KH-560 equivalent to 5%-10% of the mass of bio-based epoxy resin is added. After stirring at 50°C for 1 hour, the bottom coating is obtained.

[0011] After mixing waterborne polyurethane emulsion and graphene oxide dispersion at a mass ratio of 100: (5-10), add 0.5%-1% of dispersant FX-600 equivalent to the total mass of the mixed coating system, and ultrasonically treat for 30 minutes to obtain the intermediate layer coating.

[0012] An acrylic emulsion and fumed silica were mixed at a mass ratio of 100:(8-12), and a leveling agent of 0.1%-0.3% of the mass of the acrylic emulsion was added. After stirring for 2 hours, the outer coating was obtained.

[0013] Preferably, the bio-based epoxy resin is a soybean oil-based epoxy resin, the curing agent is one of polyamide 650, diethylenetriamine, and methyltetrahydrophthalic anhydride, the solid content of the waterborne polyurethane emulsion is 40%-50%, the concentration of the graphene oxide dispersion is 2-5wt%, and the particle size of the fumed silica is 20-50nm.

[0014] Preferably, a method for preparing environmentally friendly and wear-resistant corrugated cardboard includes the following steps:

[0015] S1 recycles waste paper, crushes it, softens it in 60℃ warm water for 2 hours, and then pulps it to obtain waste paper pulp. The waste paper pulp is then graded into long fiber pulp and short fiber pulp according to the fiber length. The waste paper pulp is mainly fed into a fiber grading device, where it is physically separated according to the length and thickness of the fibers. Nano-reinforcing agents are added to the graded long fiber pulp to prepare reinforced pulp for making wear-resistant face paper, while the graded short fiber pulp is used to make corrugated core.

[0016] S2 The reinforced pulp made from long fibers in step S1 is fed to a fourdrinier paper machine for papermaking. After forming in the wire section and dewatering in the press section, it enters the drying section and is dried at 100-110℃ to a moisture content of 7% to obtain abrasion-resistant face paper. The short fiber pulp in step S1 is formed into corrugated base paper through the same process. Then, the corrugated base paper is heated and pressed through a pair of trapezoidal toothed corrugated rolls at a temperature of 180℃ and a pressure of 7MPa to form a corrugated core with a trapezoidal wave structure.

[0017] S3 The adhesive layer was prepared by modifying corn starch;

[0018] S4 Divide the wear-resistant paper prepared in step S2 into upper wear-resistant paper and lower wear-resistant paper, and spray a composite wear-resistant coating onto the outer surface of the upper wear-resistant paper and / or the lower wear-resistant paper.

[0019] S5 involves coating both sides of the corrugated core with a modified starch-based environmentally friendly adhesive, with the coating amount controlled at 20-40 g / m² on one side, bonding it with the upper and lower abrasion-resistant paper, hot-pressing it into shape, and then cooling it at room temperature to obtain the environmentally friendly abrasion-resistant corrugated cardboard.

[0020] Preferably, in step S1, the reinforced pulp is prepared by adding 3-5 wt% nanocellulose, 1-2 wt% diatomaceous earth and 0.5-1 wt% cationic polyacrylamide to long fiber pulp and stirring until uniform; in step S2, the thickness of the wear-resistant paper is 0.3-0.5 mm; in step S5, the hot pressing parameters are a hot pressing temperature of 90°C, a pressure of 0.5 MPa and a hot pressing time of 30 s.

[0021] Preferably, in step S4, when spraying the composite wear-resistant coating, the coating amount of the bottom layer is 10-15 g / m², pre-cured at 80°C for 10 min, the coating amount of the middle layer is 15-20 g / m², cured at 100°C for 15 min, and the coating amount of the outer layer is 5-10 g / m², cured at 120°C for 10 min.

[0022] Compared with existing technologies, the beneficial effects of this invention are as follows: through the synergistic optimization of the trapezoidal corrugated core structure and the layered design of the composite coating, the compressive strength and stability are significantly improved, while taking into account the multi-dimensional requirements of coating adhesion, wear resistance and surface hardness; the material system uses waste paper as the main raw material, combined with bio-based epoxy resin and modified starch-based environmentally friendly adhesive, forming an environmentally friendly closed loop that is degradable and easily recyclable throughout the entire process, greatly reducing the consumption of non-renewable resources and the obstacles to recycling and regeneration; the wear resistance is greatly improved by the synergistic effect of the graphene-reinforced polyurethane layer and the silica nanoparticle layer, which greatly enhances the wear resistance and scratch resistance of the corrugated cardboard surface; the preparation process adopts a continuous and efficient solution of fiber graded utilization, layer-by-layer coating curing and hot pressing one-time molding, which simplifies the process and is suitable for industrial production, meeting the stringent requirements of high-end packaging and circular logistics scenarios. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, the two endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention, the mastery of the prior art by those skilled in the art, and the description of the present invention can also be used to implement the present invention using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.

[0024] Unless otherwise specified, the following examples were conducted under conventional conditions or conditions recommended by the manufacturer. All reagents used are conventional reagents used in the art unless otherwise specified. All reagents or instruments used, unless otherwise specified, are commercially available products. In this invention, unless otherwise specified, the percentage content (%) of additives refers to the percentage by mass relative to the main resin or matrix emulsion to which they are added.

[0025] Example 1

[0026] A method for preparing environmentally friendly and wear-resistant corrugated cardboard, comprising the following steps:

[0027] S1 recycles waste paper, crushes and softens it, and then pulps it to obtain waste paper pulp. According to the fiber length of the waste paper pulp, it is divided into long fiber pulp and short fiber pulp. 4 wt% nanocellulose, 1.5 wt% diatomaceous earth and 0.7 wt% cationic polyacrylamide are added to the graded long fiber pulp. After stirring evenly, wear-resistant face paper is produced. The graded short fiber pulp is used to make corrugated core.

[0028] S2 The reinforced pulp made from long fibers in step S1 is processed through papermaking, pressing, and drying to obtain a wear-resistant surface paper with a thickness of 0.4 mm; the short fiber pulp in step S1 is heated and pressed by corrugated rolls to form a corrugated core with a trapezoidal wave structure.

[0029] S3 is prepared by mixing corn starch and water at a mass ratio of 1:5, heating to 85°C to gelatinize, then adding 0.5% borax and 1% glycerin equivalent to the mass of corn starch, stirring for 15 minutes, and cooling to room temperature.

[0030] S4. The wear-resistant paper prepared in step S2 is divided into an upper wear-resistant paper and a lower wear-resistant paper. A composite wear-resistant coating is sprayed onto the outer surface of the upper wear-resistant paper and / or the lower wear-resistant paper. The preparation process of the composite wear-resistant coating is as follows: Bio-based epoxy resin and curing agent are mixed at a mass ratio of 10:1, and silane coupling agent KH-560 equivalent to 7% of the mass of bio-based epoxy resin is added. After stirring at 50°C for 1 hour, the bottom layer coating is obtained. Waterborne polyurethane emulsion and graphene oxide dispersion are mixed at a mass ratio of 100:7, and dispersant FX-600 equivalent to 0.7% of the total mass of the mixed coating system is added. After ultrasonic treatment for 30 minutes, the intermediate layer coating is obtained. Acrylic ester emulsion and fumed silica are mixed at a mass ratio of 100:10, and leveling agent equivalent to 0.2% of the mass of acrylic ester emulsion is added. After stirring for 2 hours, the outer layer coating is obtained.

[0031] S5 A modified starch-based environmentally friendly adhesive is coated on both sides of the corrugated core and bonded to the upper and lower wear-resistant face paper. The core is then hot-pressed at a temperature of 90°C, a pressure of 0.5MPa, and a hot-pressing time of 30s. After cooling, the environmentally friendly wear-resistant corrugated cardboard is obtained.

[0032] Example 2

[0033] A method for preparing environmentally friendly and wear-resistant corrugated cardboard, comprising the following steps:

[0034] S1 recycles waste paper, crushes and softens it, and then pulps it to obtain waste paper pulp. According to the fiber length of the waste paper pulp, it is divided into long fiber pulp and short fiber pulp. 3 wt% nanocellulose, 1 wt% diatomaceous earth and 0.5 wt% cationic polyacrylamide are added to the graded long fiber pulp. After stirring evenly, wear-resistant face paper is produced. The graded short fiber pulp is used to make corrugated core.

[0035] S2 The reinforcing pulp made from long fibers in step S1 is processed through papermaking, pressing, and drying to obtain a wear-resistant surface paper with a thickness of 0.3 mm; the short fiber pulp in step S1 is heated and pressed by corrugated rolls to form a corrugated core with a trapezoidal wave structure.

[0036] S3 is prepared by mixing corn starch and water at a mass ratio of 1:4, heating to 80°C to gelatinize, then adding 0.3% borax and 0.8% glycerol equivalent to the mass of corn starch, stirring for 15 minutes, and cooling to room temperature.

[0037] S4. The wear-resistant paper prepared in step S2 is divided into an upper wear-resistant paper and a lower wear-resistant paper. A composite wear-resistant coating is sprayed onto the outer surface of the upper wear-resistant paper and / or the lower wear-resistant paper. The preparation process of the composite wear-resistant coating is as follows: Bio-based epoxy resin and curing agent are mixed at a mass ratio of 10:1. Silane coupling agent KH-560, equivalent to 5% of the mass of bio-based epoxy resin, is added. After stirring at 50°C for 1 hour, a bottom layer coating is obtained. Waterborne polyurethane emulsion and graphene oxide dispersion are mixed at a mass ratio of 100:5. Dispersant FX-600, equivalent to 0.5% of the total mass of the mixed coating system, is added. The mixture is ultrasonically treated for 30 minutes to obtain an intermediate layer coating. Acrylic ester emulsion and fumed silica are mixed at a mass ratio of 100:8. Leveling agent, equivalent to 0.1% of the mass of the acrylic ester emulsion, is added. After stirring for 2 hours, an outer layer coating is obtained.

[0038] S5 A modified starch-based environmentally friendly adhesive is coated on both sides of the corrugated core and bonded to the upper and lower wear-resistant paper. The paper is then hot-pressed at a temperature of 90°C, a pressure of 0.5MPa, and a hot-pressing time of 30s. After cooling, the environmentally friendly wear-resistant corrugated cardboard is obtained.

[0039] Example 3

[0040] A method for preparing environmentally friendly and wear-resistant corrugated cardboard, comprising the following steps:

[0041] S1 recycles waste paper, crushes and softens it, and then pulps it to obtain waste paper pulp. According to the fiber length of the waste paper pulp, it is divided into long fiber pulp and short fiber pulp. 5 wt% nanocellulose, 2 wt% diatomaceous earth and 1 wt% cationic polyacrylamide are added to the graded long fiber pulp. After stirring evenly, wear-resistant face paper is produced. The graded short fiber pulp is used to make corrugated core.

[0042] S2 The reinforced pulp made from long fibers in step S1 is processed through papermaking, pressing, and drying to obtain a wear-resistant surface paper with a thickness of 0.5 mm; the short fiber pulp in step S1 is heated and pressed by corrugated rolls to form a corrugated core with a trapezoidal wave structure.

[0043] S3 is prepared by mixing corn starch and water at a mass ratio of 1:6, heating to 90°C to gelatinize, then adding 0.7% borax and 1.2% glycerol equivalent to the mass of corn starch, stirring for 15 minutes, and cooling to room temperature.

[0044] S4. The wear-resistant paper prepared in step S2 is divided into an upper wear-resistant paper and a lower wear-resistant paper. A composite wear-resistant coating is sprayed onto the outer surface of the upper wear-resistant paper and / or the lower wear-resistant paper. The preparation process of the composite wear-resistant coating is as follows: Bio-based epoxy resin and curing agent are mixed at a mass ratio of 10:1. Silane coupling agent KH-560, equivalent to 10% of the mass of bio-based epoxy resin, is added. After stirring at 50°C for 1 hour, a bottom layer coating is obtained. Waterborne polyurethane emulsion and graphene oxide dispersion are mixed at a mass ratio of 100:10. Dispersant FX-600, equivalent to 1% of the total mass of the mixed coating system, is added. After ultrasonic treatment for 30 minutes, an intermediate layer coating is obtained. Acrylic ester emulsion and fumed silica are mixed at a mass ratio of 100:12. Leveling agent, equivalent to 0.3% of the mass of the acrylic ester emulsion, is added. After stirring for 2 hours, an outer layer coating is obtained.

[0045] S5 A modified starch-based environmentally friendly adhesive is coated on both sides of the corrugated core and bonded to the upper and lower wear-resistant paper. The paper is then hot-pressed at a temperature of 90°C, a pressure of 0.5MPa, and a hot-pressing time of 30s. After cooling, the environmentally friendly wear-resistant corrugated cardboard is obtained.

[0046] Example 4

[0047] A method for preparing environmentally friendly and wear-resistant corrugated cardboard, comprising the following steps:

[0048] S1 recycles waste paper, crushes and softens it, and then pulps it to obtain waste paper pulp. According to the fiber length of the waste paper pulp, it is graded into long fiber pulp and short fiber pulp. 4 wt% nanocellulose, 1 wt% diatomaceous earth and 1 wt% cationic polyacrylamide are added to the graded long fiber pulp. After stirring evenly, wear-resistant face paper is produced. The graded short fiber pulp is used to make corrugated core.

[0049] S2 The reinforcing pulp made from long fibers in step S1 is processed through papermaking, pressing, and drying to obtain a wear-resistant surface paper with a thickness of 0.4 mm; the short fiber pulp in step S1 is heated and pressed by corrugated rolls to form a corrugated core with a trapezoidal wave structure.

[0050] S3 is prepared by mixing corn starch and water at a mass ratio of 1:5, heating to 85°C to gelatinize, then adding 0.6% borax and 0.9% glycerol equivalent to the mass of corn starch, stirring for 15 minutes, and cooling to room temperature.

[0051] S4. The wear-resistant paper prepared in step S2 is divided into an upper wear-resistant paper and a lower wear-resistant paper. A composite wear-resistant coating is sprayed onto the outer surface of the upper wear-resistant paper and / or the lower wear-resistant paper. The preparation process of the composite wear-resistant coating is as follows: soybean oil-based epoxy resin and curing agent are mixed at a mass ratio of 10:1, and silane coupling agent KH-560 equivalent to 8% of the mass of soybean oil-based epoxy resin is added. After stirring at 50°C for 1 hour, the bottom layer coating is obtained. Aqueous polyurethane emulsion and graphene oxide dispersion are mixed at a mass ratio of 100:8, and dispersant FX-600 equivalent to 0.6% of the total mass of the mixed coating system is added. After ultrasonic treatment for 30 minutes, the intermediate layer coating is obtained. Acrylic ester emulsion and fumed silica are mixed at a mass ratio of 100:11, and leveling agent equivalent to 0.2% of the mass of acrylic ester emulsion is added. After stirring for 2 hours, the outer layer coating is obtained.

[0052] S5 A modified starch-based environmentally friendly adhesive is coated on both sides of the corrugated core and bonded to the upper and lower wear-resistant paper. The paper is then hot-pressed at a temperature of 90°C, a pressure of 0.5MPa, and a hot-pressing time of 30s. After cooling, the environmentally friendly wear-resistant corrugated cardboard is obtained.

[0053] Comparative Example 1

[0054] The preparation method is basically the same as in Example 1, but in step S4, instead of spraying the composite wear-resistant coating on the outer surface of the upper and lower wear-resistant paper, only one layer of ordinary water-based polyurethane coating with a solid content of 45% is coated, with a coating amount of 30g / m², and cured at 100°C for 15 minutes. Other steps and parameters are consistent with those in Example 1.

[0055] Comparative Example 2

[0056] The preparation method is basically the same as in Example 1, but in step S4, when preparing the composite wear-resistant coating, the bottom coating is not made of bio-based epoxy resin, but is replaced with an equal amount of bisphenol A type petroleum-based epoxy resin. Other steps and parameters, including curing agent and coating composition, are the same as in Example 1.

[0057] Comparative Example 3

[0058] Instead of classifying the waste paper pulp by fiber length, all waste paper pulp was used to make abrasion-resistant face paper and corrugated core. When preparing reinforced pulp, 4wt% nanocellulose, 1.5wt% diatomaceous earth and 0.7wt% cationic polyacrylamide were added. The rest of the preparation process and parameters were completely consistent with those in Example 1.

[0059] After testing the corrugated cardboard prepared in Examples 1, 1, 2, and 3, it was found that: the recyclability of the corrugated cardboard obtained in Example 1 was greater than 95%, and its composite abrasion-resistant coating had a mass loss of less than 10 mg after standard abrasion resistance testing, and there were no penetrating scratches on the surface; Comparative Example 1 used only ordinary water-based polyurethane coating, which had weak adhesion between the coating and the paper base, and its mass loss exceeded 50 mg after the same abrasion resistance test, and obvious wear and peeling appeared on the surface. Although the recyclability was similar to that of Example 1 (about 95%), the difficulty in peeling off the coating during actual recycling may lead to a decrease in the quality of the recycled fibers;

[0060] Comparative Example 2 uses petroleum-based epoxy resin in the bottom layer, resulting in a significant reduction in the bio-based content of the product. Its biodegradability under standard soil degradation conditions is less than 30%. The degradation rate of the soybean oil-based resin layer in Example 1 is >60%, and the petroleum-based resin is difficult to separate during recycling, leading to an overall recyclability rate of less than 80% and a significant deterioration in environmental performance.

[0061] Because Comparative Example 3 did not perform fiber grading and utilization, the short fibers used in the production of face paper resulted in a loose paper structure. Its edge crush strength was only about 8.5 kN / m, which was lower than 13.2 kN / m in Example 1. The abrasion resistance of the face paper surface also decreased. After the same abrasion resistance test, the face paper substrate prepared in Comparative Example 3 showed exposed fibers, with a mass loss of up to 80 mg. The finished product was unable to meet the recycling requirements of high-strength packaging due to insufficient strength.

[0062] In summary, Example 1 is significantly superior to the comparative examples in key indicators such as recyclability, biodegradability, wear resistance life, and mechanical strength, demonstrating the advanced nature and beneficial effects of this invention in synergistically improving environmental protection and wear resistance.

[0063] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An environmentally friendly and wear-resistant corrugated cardboard, characterized in that: The corrugated cardboard comprises, from top to bottom, an upper abrasion-resistant linerboard, an upper adhesive layer, a corrugated core layer, a lower adhesive layer, and a lower abrasion-resistant linerboard. The upper and lower abrasion-resistant linerboards are made primarily from recycled waste paper pulp. The corrugated core layer has a trapezoidal corrugated structure. The upper and lower adhesive layers are made from modified starch-based environmentally friendly adhesives. The outer surfaces of the upper and lower abrasion-resistant linerboards are coated with a composite abrasion-resistant coating.

2. The environmentally friendly and wear-resistant corrugated cardboard according to claim 1, characterized in that: The upper and lower abrasion-resistant paper contain a nano-reinforcing agent, which is nanocellulose.

3. The environmentally friendly and wear-resistant corrugated cardboard according to claim 1, characterized in that: The wave height of the trapezoidal wave structure is 3.0–4.0 mm, and the wave distance is 6.0–8.0 mm.

4. The environmentally friendly and wear-resistant corrugated cardboard according to claim 1, characterized in that: The modified starch-based environmentally friendly adhesive is prepared as follows: corn starch and water are mixed at a mass ratio of 1:(4-6), heated to 80-90℃ to gelatinize, and then 0.3-0.7% borax and 0.8-1.2% glycerol equivalent to the mass of corn starch are added. The mixture is stirred for 15 minutes and then cooled to room temperature to obtain the final product.

5. The environmentally friendly and wear-resistant corrugated cardboard according to claim 1, characterized in that: The composite wear-resistant coating comprises, from the inside out, a base coating, an intermediate coating, and an outer coating. The base coating is a bio-based epoxy resin layer, the intermediate coating is a polyurethane-graphene composite layer, and the outer coating is a silica nanoparticle reinforced layer.

6. The environmentally friendly and wear-resistant corrugated cardboard according to claim 5, characterized in that: The preparation process of the composite wear-resistant coating is as follows: bio-based epoxy resin and curing agent are mixed at a mass ratio of 10:1, and silane coupling agent KH-560 equivalent to 5%-10% of the mass of bio-based epoxy resin is added. After stirring at 50°C for 1 hour, the bottom coating is obtained. After mixing waterborne polyurethane emulsion and graphene oxide dispersion at a mass ratio of 100: (5-10), add 0.5%-1% of dispersant FX-600 equivalent to the total mass of the mixed coating system, and ultrasonically treat for 30 minutes to obtain the intermediate layer coating. An acrylic emulsion and fumed silica were mixed at a mass ratio of 100:(8-12), and a leveling agent of 0.1%-0.3% of the mass of the acrylic emulsion was added. After stirring for 2 hours, the outer coating was obtained.

7. The environmentally friendly wear-resistant corrugated cardboard according to claim 6, characterized in that: The bio-based epoxy resin is a soybean oil-based epoxy resin, the curing agent is one of polyamide 650, diethylenetriamine and methyltetrahydrophthalic anhydride, the solid content of the aqueous polyurethane emulsion is 40%-50%, the concentration of the graphene oxide dispersion is 2-5wt%, and the particle size of the fumed silica is 20-50nm.

8. A method for preparing an environmentally friendly, wear-resistant corrugated cardboard according to any one of claims 1-7, characterized in that: The steps are as follows: S1 recycles waste paper, crushes and softens it, and then pulps it to obtain waste paper pulp. The waste paper pulp is graded into long fiber pulp and short fiber pulp according to the fiber length. Nano-reinforcing agents are added to the graded long fiber pulp to prepare reinforced pulp for making wear-resistant paper, while the graded short fiber pulp is used to make corrugated core. S2 The reinforced pulp made from long fibers in step S1 is processed by papermaking, pressing and drying to obtain abrasion-resistant surface paper; the short fiber pulp in step S1 is heated and pressed by corrugated rolls to form a corrugated core with a trapezoidal wave structure. S3 The adhesive layer was prepared by modifying corn starch; S4 Divide the wear-resistant paper prepared in step S2 into upper wear-resistant paper and lower wear-resistant paper, and spray a composite wear-resistant coating onto the outer surface of the upper wear-resistant paper and / or the lower wear-resistant paper. S5 involves coating both sides of the corrugated core with a modified starch-based environmentally friendly adhesive, bonding it to the upper and lower wear-resistant face paper, hot-pressing it into shape, and then cooling it to obtain the environmentally friendly wear-resistant corrugated cardboard.

9. The method for preparing an environmentally friendly and wear-resistant corrugated cardboard according to claim 8, characterized in that: In step S1, the reinforced pulp is prepared by adding 3-5 wt% nanocellulose, 1-2 wt% diatomaceous earth and 0.5-1 wt% cationic polyacrylamide to long fiber pulp and stirring until uniform; in step S2, the thickness of the wear-resistant paper is 0.3-0.5 mm; in step S5, the hot pressing parameters are a hot pressing temperature of 90℃, a pressure of 0.5 MPa and a hot pressing time of 30 s.

10. The method for preparing an environmentally friendly wear-resistant corrugated cardboard according to claim 8, characterized in that: In step S4, when spraying the composite wear-resistant coating, the coating amount of the bottom layer is 10-15 g / m², pre-cured at 80℃ for 10 min, the coating amount of the middle layer is 15-20 g / m², cured at 100℃ for 15 min, and the coating amount of the outer layer is 5-10 g / m², cured at 120℃ for 10 min.