Formula and process of novel corrugated board glue

Abstract

The invention belongs to the technical field of corrugated board glue, and particularly relates to a formula and process of novel corrugated board glue, and the novel corrugated board glue comprises the following raw materials by weight: 75.53% of water, 18.54% of starch, 0.71% of alkali, 0.28% of borax, 0.26% of a stabilizer, and 4.67% of mineral powder. The invention also discloses a preparation process of the novel corrugated board glue. The preparation process comprises the following preparation steps: S1, initial mixing; s2, performing alkali treatment and gelatinization; s3, adding borax; s4, performing vacuum pulse mixing; s5, surface modification of mineral powder; s6, mixing a stabilizer and mineral powder; and S7, temperature field gradient regulation and curing. According to the method, borax and gelatinization liquid react more sufficiently through vacuum pulse mixing, the material mixing state is optimized, a good foundation is provided for subsequent steps, surface-modified mineral powder is dispersed more quickly during mixing, the stirring efficiency is improved, the overall glue preparation time is shortened, and paper fiber pores can be more effectively filled.

Description

Technical Field

[0001] This invention relates to the field of corrugated cardboard adhesive technology, and in particular to a novel formulation and process for a corrugated cardboard adhesive. Background Technology

[0002] With the rapid development of the packaging industry, corrugated cardboard is widely used in the packaging of various products due to its lightweight, environmentally friendly, and recyclable characteristics. However, due to import restrictions on kraft paper, the paper used for corrugated cardboard is recycled paper that has been repeatedly recycled. Because of repeated shredding and recycling, the paper strength decreases significantly, resulting in a noticeable decline in the physical properties of the produced corrugated cardboard. Traditional adhesives have limitations in terms of strength, water resistance, and temperature resistance. To achieve the required physical properties and protect the product, the paper weight must be increased, raising costs.

[0003] Therefore, developing new types of corrugated cardboard adhesives to improve their performance and meet market demands is an urgent need for the current development of the industry. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a novel formulation and process for corrugated cardboard adhesive.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A novel corrugated cardboard adhesive comprises the following raw materials by weight percentage: Water 75.53%, starch 18.54%, alkali 0.71%, borax 0.28%, stabilizer 0.26%, mineral powder 4.67%, hybrid gel.

[0006] Preferably, the stabilizer is xanthan gum and guar gum in a mass ratio of 2:1.8, and the mineral powder is talc powder and mica powder in a mass ratio of 3:3.8.

[0007] The preparation process of the above-mentioned novel corrugated cardboard adhesive includes the following preparation steps: S1. Initial mixing: Add water to the reactor, turn on the stirrer, adjust the speed to 150-200 r / min, slowly add starch, and continue stirring for 10-15 min to fully disperse the starch in the water and form a uniform starch aqueous solution. S2. Alkali treatment for gelatinization: Add sodium hydroxide to the starch aqueous solution, stir evenly, raise the temperature of the reaction vessel to 50-60℃, keep it warm and stir for 20-30 minutes, so that the starch can be fully gelatinized under the action of alkali to form a gelatinized liquid with a certain viscosity. S3. Add borax. When the temperature of the gelatinized liquid drops to 40-45℃, add borax and continue to stir at 120-160r / min for 10-15min to allow the borax to fully react with the gelatinized liquid and improve the bonding stability of the glue. S4. Vacuum pulse mixing: After adding and stirring the borax, the pressure inside the reactor is evacuated to -0.04--0.06MPa. Then, nitrogen gas is introduced in a pulse manner with a pulse frequency of 1-2 times / minute and a gas introduction time of 10-15s. At the same time, the stirring speed is maintained at 140-160r / min for 5-8min. S5. Surface-modified mineral powder: Under stirring at 1000-1200 r / min, the hybrid gel dispersion is added to the mineral powder and mixed for 30-40 min to perform surface modification treatment on the mineral powder. After modification by the hybrid gel dispersion, the contact angle will increase significantly due to the change in surface properties. When the contact angle reaches a certain value and remains stable, it indicates that the surface of the mineral powder has been fully covered and modified by the silane coupling agent. S6. Mix in the stabilizer and mineral powder. Add the stabilizer and stir for 5-8 minutes to ensure the stabilizer is evenly dispersed. Then add the surface-modified mineral powder, increase the stirring speed to 180-220 r / min, and stir for 15-20 minutes to ensure that the mineral powder is fully mixed with other components. S7. Temperature gradient control curing: First, raise the temperature of the reactor to 38-40℃ and maintain it for 1 hour to allow the components of the adhesive to react initially. Then, slowly lower the temperature to 35-36℃ at a rate of 2-3℃ / h and continue curing for 1.5-2 hours. After curing, use a rotational viscometer to test the viscosity of the adhesive and use the loss on drying method to test the solid content and other indicators. If adjustments are needed, they can be made by adding water appropriately, fine-tuning the temperature, or extending the stirring curing time to finally obtain the corrugated cardboard adhesive.

[0008] The above-mentioned preparation process of a novel corrugated cardboard adhesive includes the following preparation steps for the hybrid modifier: S1. Oxidation Preparation: In a reactor equipped with a stirrer, thermometer, and reflux condenser, flake graphite was first added, and concentrated sulfuric acid was slowly poured in under ice bath conditions. The mixture was stirred at medium speed for 30 minutes to ensure uniform mixing. Subsequently, potassium permanganate was added in batches, with the reaction temperature strictly controlled to not exceed 20°C. After the addition was complete, the temperature was raised to 35°C and stirred continuously for 2 hours to complete the initial oxidation. Then, deionized water was slowly added for dilution, and the temperature was raised to 98°C and stirred for 30 minutes to promote complete oxidation. Finally, hydrogen peroxide solution was added to terminate the reaction. After the solution turned bright yellow, it was separated by centrifugation at 8000 r / min for 15 minutes and washed repeatedly with water to remove acid and impurities, thus obtaining a graphene oxide suspension. S2. Hybridization: Take an appropriate amount of graphene oxide suspension and transfer it to a reaction vessel. Adjust the stirring speed to 300 r / min. Under stirring, slowly add silane coupling agent dropwise at a mass ratio of graphene oxide to KH-550 of 1:5, along with silane coupling agent and DBTDL catalyst. Purge with nitrogen and heat to 60℃ for 4-6 hours to allow the silane coupling agent to condense with the functional groups on the surface of graphene oxide to form covalent bonds. After the reaction, separate the product by high-speed centrifugation at 10000 r / min for 20 min. Wash three times with anhydrous ethanol to remove unreacted raw materials. Finally, place the product in a vacuum drying oven at 50℃ and dry for 12 hours to obtain the graphene oxide-silane hybrid modifier. S3. For the hybrid gel, take an appropriate amount of hybrid modifier, add water and ultrasonically disperse for 10-20 minutes to form a uniform suspension. Under stirring at 150-250 r / min, slowly pour the suspension into the gelling agent solution and continue stirring for 15-30 minutes. Add calcium chloride solution at 10%-20% of sodium alginate mass to the mixture and react for 10-20 minutes. Let the formed gel stand at room temperature for 1-2 hours to solidify and wash the surface with deionized water to remove residual impurities.

[0009] Preferably, in step S5, when nitrogen is introduced into the reactor in step S4, the pressure is evacuated to -0.04 to -0.06 MPa, and then nitrogen is introduced in a pulse manner with a pulse frequency of 1-2 times / minute and a duration of 10-15 seconds per pulse.

[0010] Preferably, in step S5, the mineral powder is placed in a vacuum drying oven before surface modification and dried at 80-100℃ for 2-4 hours to remove the moisture and impurities adsorbed on the surface of the mineral powder and improve surface activity. After drying, it is passed through a 200-mesh sieve to ensure that the mineral powder particle size is uniform, which is conducive to full contact with the hybrid gel.

[0011] Preferably, in step S5, before the surface modification of the mineral powder, an appropriate amount of dispersion medium is added to the hybrid gel, and a combination of high-speed stirring and ultrasonic dispersion is used to fully disperse the hybrid gel and form a uniform and stable dispersion.

[0012] The present invention has the following beneficial effects: 1. Improved production efficiency: Vacuum pulse mixing ensures a more complete reaction between borax and the gelatinized liquid, optimizing the material mixing state and providing a good foundation for subsequent steps. Surface-modified mineral powder disperses faster during mixing, increasing stirring efficiency and reducing overall glue preparation time. Temperature gradient control during curing ensures sufficient reaction while avoiding over-reaction, improving glue quality stability. In corrugated cardboard production, this can increase production speed, reduce production interruptions due to glue quality issues, and decrease the defect rate. 2. To prevent glue deterioration, the vacuum pulse mixing process removes some volatile impurities, reducing the environment for microbial growth. Combined with the antibacterial and stabilizing effects of stabilizers, the glue's shelf life at room temperature is extended, and it is less prone to developing odors and separation. Temperature gradient-controlled curing ensures more uniform reaction of the glue's components and a more stable structure, further guaranteeing the glue's long-term stable performance. 3. Increased compressive strength and moisture resistance: Vacuum pulse mixing promotes the full reaction between borax and the gelatinized liquid, creating favorable conditions for subsequent operations. Surface-modified mineral powder is more evenly dispersed in the adhesive, more effectively filling the pores of paper fibers and working synergistically with other components. Combined with the denser network structure formed by temperature gradient-controlled curing, the compressive strength of corrugated cardboard is increased by 15-30%, and its moisture resistance is significantly improved, better maintaining structural integrity in humid environments. 4. Environmentally friendly and non-toxic: The vacuum pulse mixing process only involves changes in physical conditions and does not introduce new chemical substances. The silane coupling agent used in the surface-modified mineral powder is environmentally friendly and non-toxic. The temperature field gradient control curing also does not add any additional chemical components. The entire preparation process does not generate any harmful pollutants, meets environmental protection requirements, and the prepared glue is non-toxic, harmless, and pollution-free, meeting the needs of green production. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the overall process flow of the formulation and manufacturing process of a novel corrugated cardboard adhesive according to the present invention. Figure 2 This is a schematic diagram of the process for surface-modified mineral powder in this invention; Figure 3 This is a schematic diagram comparing the performance parameters of various embodiments and comparative examples in this invention; Figure 4 The graph shows the relationship between the contact angle of the mineral powder surface modification in this invention and the compressive strength at various temperatures: Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1:

[0015] S1. Initial Mixing: A 2000L jacketed reactor made of 304 stainless steel, equipped with a variable frequency speed-regulating stirrer, was used. 1100kg of water was added to the reactor, and the stirrer was turned on, with the speed adjusted to 180r / min. 270kg of starch was slowly added via a screw conveyor at a rate of 50kg / min. After the starch was added, stirring continued for 12 minutes, during which the turbidity of the solution was monitored in real time using an online turbidity meter. When the turbidity value stabilized at 80-100 NTU, it was determined that the starch was fully dispersed in the water, forming a uniform starch aqueous solution. During this process, the anchor-type stirring paddle effectively scraped the reactor wall, preventing starch from sticking and ensuring uniform mixing. S2. Alkali treatment for gelatinization: 10.4 kg of sodium hydroxide (≥96% purity) is slowly added to the starch aqueous solution using a diaphragm metering pump. The alkali addition time is controlled at 8-10 minutes, while maintaining a constant stirring speed. After the alkali addition is complete, the electric heating device in the reactor jacket is activated to raise the reactor temperature to 55°C at a rate of 4°C / min. Once the temperature reaches the set value, a closed-loop control system consisting of a temperature sensor and a temperature controller is used to maintain this temperature and continuously stir for 25 minutes. During this process, a small amount of gelatinized liquid is sampled every 5 minutes through the sampling port, and its viscosity is measured using a Brookfield viscometer. When the viscosity reaches 1500-2000 mPa·s, it indicates that the starch has been fully gelatinized under the action of alkali, forming a gelatinized liquid with a certain viscosity. S3. Add borax. After the gelatinized liquid has cooled naturally to 42°C through the cooling water pipes in the reactor jacket, accurately weigh 4.1 kg of borax using an electronic scale. Add the borax in three portions, with each portion 2 minutes apart, while simultaneously reducing the stirring speed to 140 rpm to prevent excessive foaming during borax addition. After all borax has been added, continue stirring for 12 minutes, using a pH meter to monitor the solution pH in real time, controlling it between 7.5 and 8.5 to ensure sufficient reaction between the borax and the gelatinized liquid, thus improving the adhesive bonding stability. S4. Vacuum Pulse Mixing: Connect the vacuum system and the nitrogen supply system. After adding and stirring the borax, start the vacuum pump and evacuate the pressure inside the reactor to -0.05 MPa within 5-8 minutes. Control the nitrogen flow through the pneumatic valve, setting the pulse frequency to 1.5 times / minute, with each pulse lasting 12 seconds, while maintaining the stirring speed at 150 rpm for 7 minutes. In a vacuum environment, the gaps between materials are more easily filled. The pressure change generated by the pulsed nitrogen flow breaks up material agglomeration, promotes molecular diffusion and penetration, and allows for a more complete reaction between the borax and the gelatinized liquid. It also helps to remove some volatile impurities in advance.

[0016] S5. Surface-modified mineral powder: Surface modification of the mineral powder was performed using a high-speed mixer. First, 68 kg of mineral powder (26.6 kg of talc and 41.4 kg of mica powder) was added to the high-speed mixer. The equipment was started, and the speed was adjusted to 1100 r / min. The hybrid gel dispersion was gradually added to the mineral powder through a metering funnel at a rate of 0.1 kg / min, with the addition process lasting 6.8–20.4 min. After the dispersion was completely added, mixing continued for 35 min. S6. Mixing the stabilizer and mineral powder: Slowly add 3.8 kg of stabilizer (1.6 kg xanthan gum and 2.2 kg guar gum) manually to the reactor while maintaining a stirring speed of 180 rpm for 6 minutes to ensure uniform dispersion of the stabilizer. Then, add 68 kg of surface-modified mineral powder to the reactor via a screw conveyor, increasing the stirring speed to 200 rpm and stirring for 18 minutes. During stirring, monitor the dispersed particle size of the mineral powder in real time using a laser particle size analyzer. When more than 90% of the particles have a particle size of less than 5 μm, ensure that the mineral powder is fully mixed with other components to exert its reinforcing and wear-resistant effects.

[0017] S7. Temperature gradient controlled curing: A reactor with programmed temperature control is used. The reactor temperature is first raised to 39℃ and maintained for 1 hour to allow the adhesive components to react initially. Multi-point temperature sensors built into the reactor monitor the temperature distribution in real time, ensuring temperature uniformity within ±1℃. After 1 hour, the programmed temperature control system is activated, slowly cooling to 35.5℃ at a rate of 2.5℃ / h, continuing curing for another 1.8 hours. After curing, the adhesive viscosity is measured using a rotational viscometer, and the solid content is measured using the loss on drying method. Adjustments can be made by adding water, fine-tuning the temperature, or extending the curing time to obtain the final corrugated cardboard adhesive. The temperature gradient, with its initial higher temperature accelerating the reaction rate and subsequent slow cooling, promotes the orderly arrangement of molecular chains and the stable formation of cross-linked structures. Adhesive cured using temperature gradient controlled curing forms a denser network structure.

[0018] Example 2 is based on Example 1, except that steps S4 and S5 are removed, and the remaining steps are the same as in Example 1.

[0019] Example 3 is based on Example 1, except that step S4 is removed, and the remaining steps are the same as in Example 1.

[0020] Example 4 is based on Example 1, except that step S5 is removed, and the remaining steps are the same as in Example 1.

[0021] It should be noted that in the comparative examples, Comparative Example 1 uses a basic corrugated cardboard adhesive preparation process without any special treatment; Comparative Example 2 only undergoes a single conventional strengthening process based on the ordinary preparation process, such as traditional constant temperature curing, to improve certain performance aspects, as shown in Table 1: Table 1: Comparison of Processing Performance of Corrugated Cardboard Adhesives Comparison Projects Compressive strength (kPa) Water resistance (strength retention rate after 24h immersion in water %) Temperature resistance (strength retention % after cycling from -10℃ to 50℃) Example 1 1850 82 78 Example 2 1300 65 60 Example 3 1520 70 68 Example 4 1480 68 66 Comparative Example 1 1100 55 52 Comparative Example 2 1200 58 55 Data comparison shows that Example 1, with its complete innovative process including vacuum pulse mixing, surface-modified mineral powder, and temperature gradient controlled curing, achieves better results in the three core indicators of compressive strength (1850 kPa), water resistance (82%), and temperature resistance (78%). This not only achieves a perfect balance between high strength and good environmental adaptability, but also clearly demonstrates the significant advantages of synergistic effects among various innovative process steps. It can reliably ensure the structural integrity of corrugated cardboard when dealing with complex application scenarios such as heavy object stacking, humid environment erosion, and extreme temperature changes.

[0022] In Example 2, after omitting the vacuum pulse mixing and surface-modified mineral powder steps, the performance experienced a precipitous decline. The compressive strength plummeted to 1300 kPa, and the water resistance and temperature resistance also dropped to 65% and 60%, respectively. This clearly demonstrates that vacuum pulse mixing plays an irreplaceable and crucial role in promoting deep material reaction and removing volatile impurities, while surface-modified mineral powder plays an irreplaceable and crucial role in enhancing the compatibility between the mineral powder and the adhesive system. The absence of these steps severely weakens the cohesive force and interfacial bonding of the adhesive, resulting in a significant reduction in overall performance.

[0023] Examples 3 and 4, which lack the vacuum pulse mixing step and the surface-modified mineral powder step respectively, exhibit performance between Examples 1 and 2, with compressive strengths of 1520 kPa and 1480 kPa respectively, and correspondingly moderate water and temperature resistance. This result further confirms that the innovative steps in this invention are interconnected and indispensable; the omission of any single step will affect the full release of the adhesive's properties, making it difficult to maximize the overall performance.

[0024] Comparative Example 1, using a basic preparation process, achieved a compressive strength of only 1100 kPa, with water resistance and temperature resistance of 55% and 52% respectively, ranking last among all groups. This fully exposes the limitations of traditional processes in meeting the stringent demands of modern packaging, failing to effectively compensate for the insufficient strength of recycled paper and making it difficult to guarantee the performance of corrugated cardboard in complex environments. Comparative Example 2, while employing a single conventional strengthening method based on a standard preparation process, increased the compressive strength to 1200 kPa and water resistance and temperature resistance to 58% and 55% respectively, but still showed a significant difference compared to the example. This further highlights that the multi-step innovative process of this invention is not a simple superposition of technologies, but rather a systematic performance optimization system built through the organic coordination of each step. In terms of improving the overall performance of corrugated cardboard adhesives, it far surpasses traditional processes and single strengthening methods.

[0025] Specifically, such as Figure 2 As shown in the analysis, the differences and advantages / disadvantages of each embodiment and comparative example in the temperature-compressive strength relationship can be clearly observed. Within the temperature range of 10℃-70℃, Embodiment 1, with its complete innovative process including vacuum pulse mixing, surface-modified mineral powder addition, and temperature field gradient controlled curing, consistently maintains a leading compressive strength, reaching 1780kPa at 10℃, peaking at 1850kPa at 25℃, and even at a high temperature of 70℃, it can still maintain a high strength of 1580kPa. Moreover, the strength decreases gradually with increasing temperature, demonstrating excellent temperature adaptability and structural stability. It is suitable for harsh scenarios such as high-temperature logistics transportation, summer outdoor warehousing, and cold chain transportation, and can effectively ensure the protection of goods by the packaging.

[0026] Example 2, due to the removal of the vacuum pulse mixing and surface-modified mineral powder steps, has limited adhesive performance. Its compressive strength is 1250 kPa at 10°C, increasing to 1300 kPa at 25°C, then gradually decreasing with rising temperature, dropping to 1050 kPa at 70°C. The bonding effect is acceptable at moderate temperatures (20-30°C), but the strength decays significantly at high temperatures. It is suitable for indoor storage and short-distance, room-temperature delivery where temperatures are relatively stable and fluctuations are minimal. Caution is needed when using it in high-temperature environments. Example 3 lacks the vacuum pulse mixing step. Its compressive strength is 1450 kPa at 10°C and reaches 1520 kPa at 25°C. Its performance falls between Examples 1 and 2. In environments with relatively stable temperatures (15-35°C), such as short-term storage in indoor temperature-controlled warehouses and regional transportation, it provides relatively stable protection. However, for long-distance transportation with large temperature variations, the impact of high-temperature sections needs to be assessed. Example 4 lacks the surface-modified mineral powder step. Its compressive strength is 1420 kPa at 10°C and 1480 kPa at 25°C. The strength change trend is similar to that of Example 3, but it is slightly inferior overall. It is suitable for packaging needs with high cost control requirements and mild temperature (10-30°C), such as local short-distance room temperature delivery. However, its protective ability is insufficient under extreme temperatures.

[0027] The two comparative examples stand in stark contrast to the series of embodiments. Comparative Example 1, using a basic preparation process, exhibits a compressive strength of only 980 kPa at 10°C, increasing to 1100 kPa at 25°C, but then rapidly decreasing with further temperature, reaching only 780 kPa at 70°C. It struggles to maintain bonding strength in fluctuating temperature environments, making it suitable only for simple storage with minimal packaging requirements and constant temperature. Comparative Example 2, while employing a single conventional strengthening process based on ordinary techniques, achieves a compressive strength of 1050 kPa at 10°C and 1200 kPa at 25°C. However, its strength decreases significantly at high temperatures, dropping to 850 kPa at 70°C. In environments carrying heavy items, long-distance transportation, or significant temperature variations, insufficient compressive strength can easily lead to packaging failure, making its practicality and reliability far inferior to the innovative process products of the embodiments.

[0028] In summary, the innovative process in Example 1 achieves an optimal balance between temperature adaptability and compressive strength; Examples 2 to 4 show progressively lower performance due to process simplification; Comparative Examples 1 and 2 are limited by traditional processes, resulting in poor performance. This fully highlights the significant advantages and important value of the innovative process of this invention in improving the performance of corrugated cardboard adhesives and meeting the needs of diverse application scenarios.

[0029] Furthermore, such as Figure 3 The figure shows the relationship between the contact angle of the mineral powder after surface modification and the compressive strength coefficient. From the data and patterns in the figure, it can be seen that in Examples 1 and 3, the contact angles were reduced to 35° and 38° respectively after surface modification of the mineral powder. Within the entire temperature range of 10°C-70°C, their compressive strength coefficients were significantly higher than those of the unmodified group. Taking 25°C as an example, the compressive strength coefficient of Example 1 reached as high as 52.86 kPa / °, and that of Example 3 reached 40.00 kPa / °, demonstrating strong compressive strength. In contrast, the compressive strength coefficients of the unmodified Examples 2 (contact angle 75°), 4 (contact angle 72°), and Comparative Examples 1 (contact angle 80°) and 2 (contact angle 78°) were all below 20 kPa / °, forming a stark contrast with the modified groups. This is because surface modification can reduce the surface energy of the mineral powder, change its surface polarity, and thus reduce the contact angle. With a reduced contact angle, the hydrophilicity of the mineral powder increases, significantly improving its compatibility with polar water molecules, starch, and other components in the adhesive system. During adhesive mixing, the mineral powder disperses more evenly, preventing agglomeration. The evenly dispersed mineral powder fills the network structure formed by the adhesive, reinforcing the skeleton. When corrugated cardboard is subjected to pressure, the well-dispersed mineral powder effectively disperses stress, preventing crack propagation and thus significantly improving the compressive strength of the corrugated cardboard.

[0030] Within the 38°-72° range, as the contact angle increases, the compressive strength coefficient decreases from 40 kPa / ° to 20 kPa / °, with a gentler but still continuous decline. This is because the surface modification effect of the mineral powder weakens after the contact angle exceeds 40°. Insufficient coupling agent coverage and deviations in process parameters cause the mineral powder to shift from "uniform dispersion" to "local agglomeration." An increase of approximately 34° in the contact angle from 38° to 72° results in a decrease of approximately 20 kPa / ° in the compressive strength coefficient, reflecting the destructive effect of agglomeration on compressive strength. Agglomerated mineral powder cannot effectively transfer stress, becoming "weak points" and accelerating the decay of compressive strength. If used in scenarios with large temperature fluctuations or medium-load transportation during this stage, the packaging's compressive strength will be significantly affected.

[0031] As the temperature gradually increased from 10℃ to 70℃, the compressive strength coefficients of all groups showed a decreasing trend, but the rate of decrease varied significantly. Example 1, with a small contact angle, had a compressive strength coefficient of 50.86 kPa / ° at 10℃, which decreased to 45.14 kPa / ° at 70℃, with a decay rate of only 11.2%, demonstrating good temperature stability. In contrast, Comparative Example 1, with a large contact angle, had a compressive strength coefficient of 12.25 kPa / ° at 10℃, which decreased to 9.75 kPa / ° at 70℃, with a decay rate as high as 20.8%, showing a significant performance decline. This is because surface modification reducing the contact angle resulted in a more stable bonding structure between the mineral powder and the adhesive system. Under high-temperature conditions, this stable structure can better resist the negative effects of temperature, maintaining the stability of the material's internal structure, thus slowing down the decay of the compressive strength coefficient. In contrast, the unmodified groups or those with large contact angles had relatively weak bonding between the mineral powder and the adhesive system, which was easily destroyed by high temperatures, leading to material instability and a rapid decrease in the compressive strength coefficient.

[0032] In summary, Example 1, with its complete surface modification process, minimizes the contact angle and maintains the highest compressive strength across the entire temperature range, exhibiting the best performance. Even at 70°C, it maintains a relatively high compressive strength of 45.14 kPa / °, providing reliable protection for packaged goods. Example 3, although also modified, has a slightly larger contact angle than Example 1, and its overall compressive strength is lower, but it still shows a significant advantage over the unmodified group. Unmodified Examples 2 and 4, as well as Comparative Examples 1 and 2, have larger contact angles, resulting in not only low initial compressive strength but also a more pronounced decrease in compressive strength as temperature increases. Comparative Example 1's compressive strength at 70°C is only 9.75 kPa / °, less than a quarter of that of Example 1. This fully highlights the importance of surface modification processes in improving the compressive strength and temperature adaptability of materials. Different surface modification processes and contact angle controls directly determine the performance of corrugated cardboard adhesives under different temperature environments, providing an important basis for selecting appropriate processes and materials according to specific needs in practical applications.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A novel corrugated cardboard adhesive, characterized in that, The raw materials include the following weight percentages: Water 75.53%, starch 18.54%, alkali 0.71%, borax 0.28%, stabilizer 0.26%, mineral powder 4.67%, hybrid gel.

2. The novel corrugated cardboard adhesive according to claim 1, characterized in that, The stabilizer is xanthan gum and guar gum in a mass ratio of 2:1.8, and the mineral powder is talc powder and mica powder in a mass ratio of 3:3.

8.

3. The preparation process of a novel corrugated cardboard adhesive as described in any one of claims 1-2, characterized in that, The preparation steps include the following: S1. Initial mixing: Add water to the reactor, turn on the stirrer, adjust the speed to 150-200 r / min, slowly add starch, and continue stirring for 10-15 min to fully disperse the starch in the water and form a uniform starch aqueous solution. S2. Alkali treatment for gelatinization: Add sodium hydroxide to the starch aqueous solution, stir evenly, raise the temperature of the reaction vessel to 50-60℃, keep it warm and stir for 20-30 minutes, so that the starch can be fully gelatinized under the action of alkali to form a gelatinized liquid with a certain viscosity. S3. Add borax. When the temperature of the gelatinized liquid drops to 40-45℃, add borax and continue to stir at 120-160r / min for 10-15min to allow the borax to fully react with the gelatinized liquid and improve the bonding stability of the glue. S4. Vacuum pulse mixing: After adding and stirring the borax, nitrogen gas is introduced into the reactor while maintaining the stirring speed at 140-160 r / min for 5-8 min. S5. Surface-modified mineral powder: Under stirring at 1000-1200 r / min, the hybrid gel dispersion is added to the mineral powder and mixed for 30-40 min to perform surface modification treatment on the mineral powder. After modification by the hybrid gel dispersion, the contact angle will increase significantly due to the change in surface properties. When the contact angle reaches a certain value and remains stable, it indicates that the surface of the mineral powder has been fully covered and modified by the silane coupling agent. S6. Mix in the stabilizer and mineral powder. Add the stabilizer and stir for 5-8 minutes to ensure the stabilizer is evenly dispersed. Then add the surface-modified mineral powder, increase the stirring speed to 180-220 r / min, and stir for 15-20 min to ensure that the mineral powder is fully mixed with other components; S7. Temperature gradient control curing: First, raise the temperature of the reactor to 38-40℃ and maintain it for 1 hour to allow the components of the adhesive to react initially. Then, slowly lower the temperature to 35-36℃ at a rate of 2-3℃ / h and continue curing for 1.5-2 hours. After curing, use a rotational viscometer to test the viscosity of the adhesive and use the loss on drying method to test the solid content and other indicators. If adjustments are needed, they can be made by adding water appropriately, fine-tuning the temperature, or extending the stirring curing time to finally obtain the corrugated cardboard adhesive.

4. The preparation process of the novel corrugated cardboard adhesive as described in claim 4, characterized in that, The hybrid gel in step S5 includes the following preparation steps: S1. Oxidation preparation: In a reaction vessel equipped with a stirrer, thermometer, and reflux condenser, flake graphite was mixed with concentrated sulfuric acid under ice bath conditions and stirred at medium speed for 30 min. Potassium permanganate was added in batches, with the temperature controlled at ≤20℃. After the addition was complete, the temperature was raised to 35℃ and stirred for 2 h. After dilution with water, the temperature was raised to 98℃ and stirred for 30 min. Hydrogen peroxide was added to terminate the reaction. After the solution turned yellow, it was centrifuged at 8000 r / min for 15 min and washed with water to obtain a graphene oxide suspension. S2. Hybridization: A suspension of graphene oxide was placed in a reaction vessel and stirred at 300 r / min. KH-550 was added dropwise at a mass ratio of 1:5, along with a silane coupling agent and a DBTDL catalyst. Nitrogen gas was introduced, and the reaction was carried out at 60°C for 4-6 h. After the reaction, the mixture was centrifuged at 10000 r / min for 20 min, washed three times with anhydrous ethanol, and then vacuum dried at 50°C for 12 h to obtain the hybrid modifier. S3. For the hybrid gel, take an appropriate amount of hybrid modifier, add water and ultrasonically disperse for 10-20 minutes to form a uniform suspension. Under stirring at 150-250 r / min, slowly pour the suspension into the gelling agent solution and continue stirring for 15-30 minutes. Add calcium chloride solution at 10%-20% of sodium alginate mass to the mixture and react for 10-20 minutes. Let the formed gel stand at room temperature for 1-2 hours to solidify and wash the surface with deionized water to remove residual impurities.

5. The preparation process of the novel corrugated cardboard adhesive according to claim 3, characterized in that, In step S4, when nitrogen is introduced into the reactor, the pressure is evacuated to -0.04 to -0.06 MPa, and then nitrogen is introduced in a pulse manner with a pulse frequency of 1-2 times / minute and a duration of 10-15 seconds per pulse.

6. The preparation process of the novel corrugated cardboard adhesive according to claim 3, characterized in that, In step S5, before surface modification, the mineral powder is placed in a vacuum drying oven and dried at 80-100℃ for 2-4 hours to remove adsorbed moisture and impurities from the surface of the mineral powder and improve surface activity. After drying, it is passed through a 200-mesh sieve to ensure uniform particle size of the mineral powder, which is conducive to full contact with the hybrid gel.

7. The preparation process of the novel corrugated cardboard adhesive according to claim 3, characterized in that, In step S5, before the surface modification of the mineral powder, an appropriate amount of dispersion medium is added to the hybrid gel, and the hybrid gel is fully dispersed by a combination of high-speed stirring and ultrasonic dispersion to form a uniform and stable dispersion.

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