An adhesive and a method for preparing the same

Abstract

The application discloses a kind of adhesive and preparation method thereof, adhesive includes main reagent A and curing agent B is formed according to mass ratio 5:1, main reagent A is according to the component including the following mass parts: polyester polyol is 140~180 parts, hydroxylated modified soybean oil is 140~180 parts, dispersing agent is 8~12 parts, heavy calcium powder is 550~610 parts, active calcium carbonate is 45~55 parts, 5A activated powder is 35~45 parts.Advantages: in main agent A, 550~610 parts of heavy calcium powder is added, and the proportion of inorganic filler in the system is more than 55%.Heavy calcium powder is used as high-hardness rigid filler, and a three-dimensional skeleton structure is formed in the adhesive layer after curing, which improves the compression strength and surface hardness of the adhesive layer.When external force acts on the adhesive layer, high-modulus filler particles bear the main load, limit the movement of polymer chain segment, so that the shore hardness is more than 75.Under the premise of not relying on expensive rigid resin, the hardness can be greatly improved only by the physical strengthening effect of cheap filler, which solves the technical problem that high-cost raw materials must be used to pursue hardness in the prior art.

Description

Technical Field

[0001] This invention relates to the field of adhesives, specifically to an adhesive and its preparation method. Background Technology

[0002] Polyurethane adhesives are widely used in wood processing, building decoration, automobile manufacturing, and shoe bonding due to their excellent bonding properties, good flexibility, and chemical resistance. Traditional polyurethane adhesives typically consist of polyol components and isocyanate curing agents. To improve the hardness of the adhesive layer, existing technologies often employ two approaches: one is to use high-functionality polyols or introduce rigid chain segment structures, such as using aromatic polyester polyols or adding epoxy resin for modification; the other is to increase the crosslinking density, such as increasing the isocyanate index or using multifunctional curing agents. However, while these methods can improve hardness to some extent, they often lead to a significant increase in raw material costs and may increase the brittleness of the adhesive layer and reduce its impact resistance. For example, the cost of using specialty polyols is usually 2 to 3 times that of ordinary polyester polyols, and the price of high-functionality isocyanates is also much higher than that of ordinary MDI or TDI. To reduce costs, existing technologies mainly achieve this by adding inorganic fillers, commonly including calcium carbonate, talc, and kaolin. However, simply adding ordinary fillers often brings a series of problems: First, the filler has poor compatibility with the resin matrix, easily leading to interface defects and a decrease in the mechanical properties of the adhesive layer; second, uneven dispersion of the filler may cause local stress concentration, which in turn reduces hardness; third, ordinary fillers do not have water removal capabilities, and residual moisture in the system reacts with isocyanates to generate bubbles, destroying the density of the adhesive layer. To address this, some existing technologies use activated calcium carbonate or coupling agents to treat the filler to improve interfacial bonding, but this increases raw material costs and process complexity. Furthermore, existing adhesive formulations often require the addition of various additives to ensure storage stability and workability, such as dehydrating agents, anti-settling agents, and wetting and dispersing agents, which further increases costs. Especially for applications requiring high hardness (such as bonding rigid slabs and stone repair), existing products often struggle to achieve ideal hardness indicators while maintaining a low cost.

[0003] Therefore, it is necessary to provide adhesives and their preparation methods. Summary of the Invention

[0004] The present invention provides an adhesive and its preparation method, which effectively solves the problems of low hardness and high cost of existing adhesives.

[0005] The technical solution adopted in this invention is: an adhesive comprising a main reagent A and a curing agent B in a mass ratio of 5:1. The main reagent A comprises the following components in parts by mass: 140-180 parts of polyester polyol, 140-180 parts of hydroxylated modified soybean oil, 8-12 parts of dispersant, 550-610 parts of heavy calcium carbonate powder, 45-55 parts of activated calcium carbonate, and 35-45 parts of 5A activating powder.

[0006] Furthermore, the polyester polyol comprises 160 parts, the hydroxylated modified soybean oil comprises 160 parts, the dispersant comprises 10 parts, the heavy calcium carbonate powder comprises 580 parts, the activated calcium carbonate comprises 50 parts, and the 5A activating powder comprises 40 parts.

[0007] Furthermore, the heavy calcium carbonate powder is 1250 mesh heavy calcium carbonate.

[0008] Furthermore, the dispersant is a polymeric dispersant or a wetting dispersant.

[0009] Furthermore, the 5A activated powder is a 5A type molecular sieve activated powder.

[0010] Furthermore, the curing agent B is an isocyanate-based curing agent.

[0011] Furthermore, the activated calcium carbonate is light or heavy calcium carbonate that has undergone surface activation treatment.

[0012] A preparation method for the adhesive, comprising the following steps: S1. Mixing and stirring: Add the formulated amount of polyester polyol, hydroxylated modified soybean oil, and dispersant to a mixer and mix at a stirring speed of 200-500 rpm for 3-8 minutes; then add activated calcium carbonate and 5A activating powder and stir at a stirring speed of 300-600 rpm for 5-10 minutes; finally add heavy calcium carbonate powder and maintain the stirring speed at 300-600 rpm for 15-20 minutes to obtain a uniform slurry; S2. Vacuum dehydration treatment: Transfer the slurry obtained in step S1 to a vacuum-capable reaction vessel, heat it to 60-110℃ with stirring, and evacuate it to a vacuum degree below ~0.08 MPa, and maintain this condition for 1-3 hours.

[0013] Furthermore, in step S1, the heavy calcium carbonate powder is added in 5 portions, with 110 to 130 portions added each time.

[0014] Furthermore, in step S2, the temperature of the vacuum dehydration treatment is 80~100℃, the vacuum degree is less than ~0.09 MPa, and the treatment time is 1.5~2.5 hours.

[0015] Beneficial effects of the invention: 1. This application adds 550-610 parts of heavy calcium carbonate powder to the main agent A, increasing the proportion of inorganic filler in the system to over 55%. As a high-hardness rigid filler, heavy calcium carbonate powder forms a three-dimensional skeletal structure in the adhesive layer after curing, significantly improving the compressive strength and surface hardness of the adhesive layer. When external force is applied to the adhesive layer, the high-modulus filler particles bear the main load, restricting the movement of polymer chain segments, resulting in a Shore hardness of over 75. Compared with traditional adhesives, this solution achieves a significant increase in hardness without relying on expensive rigid resins, solely through the physical reinforcement of inexpensive fillers, solving the technical problem of existing technologies that necessitate the use of high-cost raw materials to pursue higher hardness.

[0016] 2. This application simultaneously adds activated calcium carbonate and 5A activating powder to form a multi-level particle size filling system with heavy calcium carbonate powder. The activated calcium carbonate undergoes surface activation treatment, forming a strong interfacial bond with the resin matrix, ensuring effective stress transfer to the filler particles. The 5A activating powder, as a molecular sieve-type dehydrating agent, thoroughly adsorbs moisture in the system, preventing air bubbles from forming during curing and ensuring a dense, defect-free adhesive layer. The synergistic effect of these three components maximizes the filler packing density, eliminates microscopic defects within the adhesive layer, and fully utilizes its hardness. Experiments show that compared to a single filler, the multi-level filler system can further increase hardness by 20%~30%, and the cured adhesive layer has a smooth surface and uniform texture.

[0017] 3. In this application, the amount of heavy calcium carbonate powder is as high as 550-610 parts, accounting for more than 55% of the mass of the main agent A. As one of the cheapest fillers in industry, heavy calcium carbonate powder costs only 1 / 5 to 1 / 10 of polyester polyol. By replacing expensive resins in large quantities, the raw material cost per unit mass of adhesive is reduced by 30% to 50%. Taking a typical formulation as an example, the cost per ton can be reduced from 12,000 yuan to below 7,000 yuan after adopting this solution. At the same time, the introduction of lower-priced hydroxylated modified soybean oil to replace part of the polyester polyol further reduces costs. The high filler content design compresses raw material costs to the extreme while ensuring performance, resulting in a significant cost-performance advantage for the product.

[0018] 4. In this application, the amount of heavy calcium carbonate powder is as high as 550-610 parts, accounting for more than 55% of the mass of the main agent A. As one of the cheapest fillers in industry, heavy calcium carbonate powder costs only 1 / 5 to 1 / 10 of polyester polyol. By replacing expensive resins in large quantities, the raw material cost per unit mass of adhesive is reduced by 30% to 50%. Taking a typical formulation as an example, the cost per ton can be reduced from 12,000 yuan to below 7,000 yuan after adopting this scheme. At the same time, the introduction of lower-priced hydroxylated modified soybean oil to replace part of the polyester polyol further reduces costs. The high filler content design compresses raw material costs to the extreme while ensuring performance, resulting in a significant cost-performance advantage for the product. Attached Figure Description

[0019] Figure 1 A flowchart illustrating the preparation method provided in the embodiments of this application. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] The first embodiment provided in this application is an adhesive comprising a main reagent A and a curing agent B in a mass ratio of 5:1. The main reagent A comprises the following components in parts by mass: 140-180 parts of polyester polyol, 140-180 parts of hydroxylated modified soybean oil, 8-12 parts of dispersant, 550-610 parts of heavy calcium carbonate powder, 45-55 parts of activated calcium carbonate, and 35-45 parts of 5A activating powder.

[0022] In the above design, the amount of heavy calcium carbonate powder is as high as 550-610 parts, accounting for more than 55% of the total mass of the main agent A. As a rigid inorganic filler, heavy calcium carbonate powder forms a three-dimensional skeleton structure after the adhesive is cured, significantly improving the compressive strength and surface hardness of the adhesive layer. When external force is applied to the adhesive layer, the high-modulus heavy calcium carbonate powder particles bear the main load, restricting the free movement of polymer chain segments, thereby making the adhesive layer exhibit higher hardness and resistance to deformation. Activated calcium carbonate, after surface activation treatment, forms a strong chemical bond or physical entanglement with the polyester polyol and hydroxylated modified soybean oil matrix. This enhanced interfacial bonding force allows stress to be effectively transferred to the filler particles, avoiding local yielding caused by interfacial debonding, thus macroscopically manifesting as a further increase in hardness. Compared with ordinary untreated calcium carbonate, the addition of activated calcium carbonate can increase hardness by 15%-20%. 5A activated powder, as a molecular sieve-type dehydrating agent, can completely adsorb trace amounts of moisture in the system, preventing moisture from reacting with the isocyanate curing agent to generate carbon dioxide bubbles. The presence of air bubbles significantly reduces the density and effective load-bearing area of ​​the adhesive layer, a major factor leading to decreased hardness. This solution, through the addition of 5A activating powder, ensures that the cured adhesive layer is free of pore defects, forming a uniform and dense cross-linked network, maximizing the inherent hardness of the filler and resin. Polyester polyol molecules contain polar ester groups and rigid benzene ring structures (in the case of aromatic polyesters), inherently endowing the adhesive with high cohesive strength and modulus. When compounded with hydroxylated modified soybean oil, it maintains a certain rigidity while avoiding the excessive brittleness that may result from using polyester polyols alone, achieving a balance between hardness and toughness. The main agent A and curing agent B are mixed at a 5:1 mass ratio, ensuring the ratio of hydroxyl and isocyanate groups in the system is within a reasonable range, forming a moderately cross-linked network structure. Too low a cross-linking density results in insufficient hardness, while too high a cross-linking density, although increasing hardness, increases brittleness. This solution, through extensive experimental screening, has achieved a 5:1 ratio that precisely reaches the critical point of "high hardness without brittleness," maintaining acceptable toughness while obtaining high hardness. Heavy calcium carbonate powder is one of the cheapest inorganic fillers in industry, typically costing only 1 / 5 to 1 / 10 of polyester polyols. In this formulation, the amount of heavy calcium carbonate powder is as high as 550-610 parts, accounting for over 55% of the main agent A. This means that the "volume" that would normally be borne by expensive resin is largely replaced by the inexpensive filler, directly reducing the raw material cost per unit mass of adhesive by 30%-50%. For example, in a typical formulation, if a resin system is used entirely, the cost per ton is approximately 12,000 yuan; with the high filler content design of this formulation, the cost per ton can be reduced to below 7,000 yuan, a reduction of over 40%. Hydroxylated modified soybean oil is a bio-based raw material, typically cheaper than petroleum-based polyester polyols. In this formulation, the amount of hydroxylated modified soybean oil is comparable to that of polyester polyol (140-180 parts each), replacing some of the expensive polyester polyol with readily available and inexpensive soybean oil, further reducing costs while maintaining performance.Furthermore, the introduction of soybean oil reduces reliance on external petrochemical raw materials, aligning with the trends of green environmental protection and sustainable development. Traditional polyurethane adhesives often employ chemical dehydrating agents such as triethyl orthoformate and oxazolidines. These additives are expensive (typically 3-5 times the cost of molecular sieves) and may participate in reactions, affecting performance. This solution uses inexpensive 5A molecular sieve activated powder as a physical dehydrating agent, which is inexpensive and does not consume isocyanate, significantly reducing additive costs while achieving the same dehydration effect. Through reasonable filler gradation and surface activation treatment, this solution achieves good filler suspension and stable system storage without adding expensive additives such as anti-settling agents and thixotropic agents. The dispersant dosage is only 8-12 parts, a conventional addition amount, without introducing additional cost burden. The entire main agent A contains only 6 essential components, resulting in a simple formulation and low raw material procurement and inventory management costs. A comprehensive evaluation of hardness performance and cost shows that the unit cost hardness value (i.e., the hardness increment obtained per unit cost) of this solution is far higher than existing technologies. Based on the ratio of Shore D hardness to cost per ton, existing similar products have a ratio of approximately 0.02 to 0.03, while this solution can reach 0.05 to 0.06, more than doubling the cost-effectiveness and giving it a significant competitive advantage in the market.

[0023] Specifically: the polyester polyol is 160 parts, the hydroxylated modified soybean oil is 160 parts, the dispersant is 10 parts, the heavy calcium carbonate powder is 580 parts, the activated calcium carbonate is 50 parts, and the 5A activating powder is 40 parts.

[0024] In the above design, the specific ratio is a golden ratio selected through extensive experimentation. At this ratio, the mass ratio of polyester polyol to hydroxylated modified soybean oil is 1:1, achieving an optimal balance between rigidity and flexibility in the adhesive—avoiding both excessive polyester polyol leading to an overly hard and cracked layer, and excessive soybean oil causing a decrease in strength. The 10 parts dispersant ensure sufficient wetting and dispersion of the high-filler content, preventing agglomeration. The combination of 580 parts heavy calcium carbonate powder, 50 parts activated calcium carbonate, and 40 parts 5A activating powder keeps the total filler volume near the critical bulk density, minimizing costs while ensuring the resin matrix adequately coats all filler particles, resulting in a dense and defect-free adhesive layer after curing. This precise ratio is easily repeatable in industrial production, exhibiting moderate viscosity during mixing—avoiding both insufficient filler leading to low viscosity and sagging, and excessive filler causing mixing difficulties or air bubble removal—providing good operational tolerance. Tests have shown that the adhesive with this optimized ratio exhibits excellent performance in key indicators such as tensile strength, elongation at break, water resistance, and storage stability, making it an optimal industrial solution that balances cost and performance.

[0025] Specifically, the heavy calcium carbonate powder is 1250 mesh heavy calcium carbonate.

[0026] In the above design, 1250-mesh heavy calcium carbonate is an ultrafine powder with an average particle size of approximately 10 micrometers. This particle size ensures good suspension of the filler in the adhesive system, preventing sedimentation, and also forms a reasonable particle size distribution with activated calcium carbonate and 5A activated powder. Small particles fill the gaps between large particles, increasing the bulk density and thus enhancing the compactness and strength of the cured adhesive layer. The 1250-mesh fineness results in a smooth and delicate surface after adhesive curing, making it particularly suitable for applications requiring aesthetics (such as furniture paneling and stone bonding), avoiding the surface roughness caused by coarse filler particles. Ultrafine heavy calcium carbonate powder plays a certain role in toughening and strengthening the resin matrix. Its large specific surface area and strong interfacial bonding with the resin allow it to effectively transfer stress under load, preventing crack propagation and improving the overall mechanical properties of the adhesive. The 1250-mesh fineness ensures performance while being easy to disperse in industrial production, requiring no excessive dispersion time or special dispersion equipment, thus exhibiting good process adaptability.

[0027] Specifically, the dispersant is a polymeric dispersant or a wetting dispersant.

[0028] In the above design, polymeric dispersants or wetting dispersants have long molecular chains and multiple anchoring groups, enabling them to rapidly adsorb onto the surface of filler particles, reduce solid-liquid interfacial tension, and allow the filler to be quickly wetted by the resin in the initial stage of mixing, significantly shortening the dispersion time and improving production efficiency. These dispersants, through steric hindrance or electrostatic repulsion, effectively prevent the re-aggregation of dispersed filler particles, ensuring the adhesive remains uniform and stable during storage and use, and avoiding performance degradation due to filler sedimentation or agglomeration. In high-filler systems such as those containing heavy calcium carbonate, polymeric dispersants can significantly reduce the viscosity of the system and improve flowability, allowing the adhesive to maintain good workability even with high filler content, facilitating coating or pouring. Good dispersion results in uniform distribution of the filler in the resin matrix, with no defects inside the cured adhesive layer, leading to more stable and reliable mechanical properties. Simultaneously, water resistance and chemical resistance are also improved due to the improved interfacial bonding.

[0029] Specifically: the 5A activated powder is 5A type molecular sieve activated powder.

[0030] In the above design, the 5A type molecular sieve has a uniform microporous structure (pore size approximately 5 mm). It can selectively adsorb water molecules (kinetic diameter approximately 2.6 mm). It has no adsorption effect on other components in the resin system. As an activated powder, it has a larger specific surface area and better dispersibility, which can quickly capture free and adsorbed water in the system, reducing the moisture content to an extremely low level. In polyurethane systems, moisture reacts with isocyanate curing agents to generate carbon dioxide bubbles, causing pinholes, bubbles, or foaming in the adhesive layer, which seriously affects the bonding strength and appearance. The addition of 5A activated powder can completely eliminate this problem, ensuring that the cured adhesive layer is dense and bubble-free. Adhesives may slowly deteriorate during storage due to the penetration of environmental moisture. 5A activated powder can continuously adsorb trace amounts of moisture entering the system, significantly extending the storage stability of the main agent A and avoiding gelation or performance degradation caused by moisture accumulation. 5A molecular sieves are chemically inert, do not react with resins or curing agents, and do not change the system formulation or produce by-products like some chemical dehydrating agents. It is a safe and pure physical dehydration method.

[0031] Specifically, the curing agent B is an isocyanate-based curing agent.

[0032] In the above design, isocyanate curing agents (such as MDI, TDI, PAPI, etc.) can undergo a rapid and complete addition reaction with the hydroxyl groups in polyester polyols and hydroxylated modified soybean oil to form a polyurethane structure. This reaction can be carried out at room temperature without the need for external catalysts or heating, making construction convenient. By selecting isocyanates with different functionalities (such as difunctional MDI or multifunctional PAPI), the crosslinking density can be adjusted, thereby controlling the hardness, flexibility, heat resistance, and other properties of the cured adhesive layer to meet different application requirements. Isocyanate groups can not only react with the hydroxyl groups in the resin, but also form chemical bonds with the active hydrogen on the substrate surface (such as the cellulose hydroxyl groups in wood and the oxide layer on the metal surface), thereby significantly improving the adhesion of the adhesive to various substrates. The polyurethane structure itself has excellent oil resistance, solvent resistance, and dilute acid and alkali resistance. The use of isocyanate curing agents further enhances this characteristic, enabling the adhesive to be used for a long time in harsh environments.

[0033] Specifically, the activated calcium carbonate is light or heavy calcium carbonate that has undergone surface activation treatment.

[0034] In the above design, the surface-activated calcium carbonate (usually coated with stearic acid, titanate coupling agents, or aluminate coupling agents) changes from hydrophilic to lipophilic, significantly improving its compatibility with organic resin matrices such as polyester polyols and hydroxylated modified soybean oil. The activated layer forms a flexible interface between the resin and filler, effectively transferring stress under load and preventing interface debonding, thereby improving the tensile strength and impact resistance of the adhesive. Surface activation reduces the tendency for calcium carbonate particles to agglomerate, making them easier to open and uniformly disperse during mixing, reducing dispersion time and energy consumption, and avoiding stress concentration points caused by agglomerates. Unactivated calcium carbonate, due to its strong surface polarity, easily adsorbs resin to form a gel structure, leading to an abnormally high viscosity of the system. Activation alleviates this phenomenon, allowing the highly filled system to maintain good fluidity and facilitating construction. The activated layer has a certain degree of hydrophobicity, preventing water molecules from penetrating along the filler-resin interface, significantly improving the water resistance and moisture aging resistance of the cured adhesive layer, and extending the service life of the bonded parts in humid environments.

[0035] like Figure 1 As shown, the second embodiment provided in this application is a preparation method for preparing the adhesive, comprising the following steps: S1. Mixing and stirring: Add the formulated amount of polyester polyol, hydroxylated modified soybean oil, and dispersant to a mixer and mix at a stirring speed of 200-500 rpm for 3-8 minutes; then add activated calcium carbonate and 5A activating powder and stir at a stirring speed of 300-600 rpm for 5-10 minutes; finally add heavy calcium carbonate powder and maintain the stirring speed at 300-600 rpm for 15-20 minutes to obtain a uniform slurry; S2. Vacuum dehydration treatment: Transfer the slurry obtained in step S1 to a vacuum-capable reaction vessel, heat it to 60-110℃ with stirring, and evacuate it to a vacuum degree below ~0.08 MPa, and maintain this condition for 1-3 hours.

[0036] In the above design, in step S1, the polyester polyol, hydroxylated modified soybean oil, and dispersant are first mixed at low speed to ensure the dispersant is fully dissolved and pre-wetted into the resin system. Then, activated calcium carbonate and 5A activating powder are added and stirred at medium speed to ensure these two functional fillers preferentially contact the resin and distribute evenly. Finally, heavy calcium carbonate powder is added, and stirring is maintained until homogeneous. This step-by-step addition method avoids localized agglomeration or uneven dispersion caused by adding all fillers at once, ensuring that each filler is fully wetted and dispersed. Initial stirring uses a low speed of 200-500 rpm to prevent splashing and shear overheating; after adding activated calcium carbonate and 5A activating powder, the speed is increased to 300-600 rpm to provide sufficient shear force to break up any slight agglomerates; finally, after adding heavy calcium carbonate powder, this speed is maintained to gradually homogenize the system. The speed changes throughout the process are perfectly matched to the material characteristics. Step S2 treats the slurry at 60–110°C and a vacuum below -0.08 MPa for 1–3 hours, effectively removing dissolved water, adsorbed water, and air bubbles introduced during dispersion. High temperature promotes water molecule movement, while vacuum accelerates water evaporation; the synergistic effect of these two factors reduces the final slurry's water content to an extremely low level (typically <0.05%), clearing the way for subsequent reactions with the isocyanate curing agent. The entire process, from mixing to dehydration, is completed within the same or transferable system, avoiding potential secondary contamination or water absorption introduced in intermediate steps, thus ensuring product quality stability and consistency.

[0037] Specifically: In step S1, the heavy calcium carbonate powder is added in 5 portions, with 110 to 130 portions added each time.

[0038] In the above design, the total amount of heavy calcium carbonate powder in the high-filling system is as high as 550-610 parts. If added all at once, the instantaneous load on the mixer will increase dramatically, which may lead to motor overload, difficulty in mixing, or even damage to the equipment. Adding it in 5 stages allows the load to increase gradually, protecting the equipment while ensuring the mixing effect. Each batch of heavy calcium carbonate powder is fully wetted and dispersed in the existing slurry. The next batch is added only after the powder is basically uniform, avoiding the phenomenon of "dry powder coating"—that is, the newly added powder is coated by the already wetted powder, and dry powder agglomerates still exist inside. This "small amount, multiple times" strategy ensures that each part of heavy calcium carbonate powder is fully wetted. Each time a new powder is added, the viscosity of the system will temporarily increase, and the shear force will increase accordingly, which is conducive to breaking up any possible soft agglomerates. As dispersion progresses, the viscosity decreases, and the next batch is added. This cycle ensures that the shear energy is used efficiently throughout the process. The slurry prepared by this method shows an extremely uniform distribution of filler under a microscope, with no visible agglomerates. The mechanical properties of the cured adhesive layer are more stable, with small data fluctuations and high batch consistency.

[0039] Specifically: in step S2, the temperature of the vacuum dehydration treatment is 80~100℃, the vacuum degree is less than ~0.09MPa, and the treatment time is 1.5~2.5 hours.

[0040] In the above design, the temperature range of 80~100℃ provides sufficient heat energy to promote the escape of water molecules while avoiding the potential for resin thermal oxidative degradation or component volatilization caused by excessively high temperatures (above 110℃). At this temperature, the polyester polyol and hydroxylated modified soybean oil remain stable without side reactions. A vacuum level below -0.09 MPa (i.e., an absolute pressure below 0.01 MPa) is a readily achievable high vacuum range industrially. Under these conditions, the boiling point of water decreases significantly (below approximately 45℃), and the water in the system rapidly vaporizes and is extracted under the combined effects of heating and vacuum, resulting in extremely high dehydration efficiency. The water content can be reduced to below 0.03% within 1.5~2.5 hours. Compared to a wider range (1~3 hours), 1.5~2.5 hours is an optimized time window that ensures thorough dehydration without excessively prolonging the production cycle, thus improving production efficiency. The dehydration efficiency per unit energy consumption is highest when the temperature is between 80 and 100°C and the pressure is -0.09 MPa. This avoids increased energy consumption due to prolonged processing time caused by low temperature or insufficient vacuum, and also avoids resource waste caused by excessively harsh conditions.

[0041] In further detail, it should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adhesive, characterized in that: It comprises a main reagent A and a curing agent B in a mass ratio of 5:

1. The main reagent A comprises the following components in parts by mass: 140-180 parts of polyester polyol, 140-180 parts of hydroxylated modified soybean oil, 8-12 parts of dispersant, 550-610 parts of heavy calcium carbonate powder, 45-55 parts of activated calcium carbonate, and 35-45 parts of 5A activating powder.

2. The adhesive according to claim 1, characterized in that: The polyester polyol comprises 160 parts, the hydroxylated modified soybean oil comprises 160 parts, the dispersant comprises 10 parts, the heavy calcium carbonate powder comprises 580 parts, the activated calcium carbonate comprises 50 parts, and the 5A activating powder comprises 40 parts.

3. The adhesive according to claim 1, characterized in that: The heavy calcium carbonate powder is 1250 mesh heavy calcium carbonate.

4. The adhesive according to claim 1, characterized in that: The dispersant is a polymeric dispersant or a wetting dispersant.

5. The adhesive according to claim 1, characterized in that: The 5A activated powder is a 5A type molecular sieve activated powder.

6. The adhesive according to claim 1, characterized in that: The curing agent B is an isocyanate-based curing agent.

7. The adhesive according to claim 1, characterized in that: The activated calcium carbonate is light or heavy calcium carbonate that has undergone surface activation treatment.

8. A preparation method for preparing the adhesive according to any one of claims 1 to 7, characterized in that: Includes the following steps: S1. Mixing and stirring: Add the formulated amount of polyester polyol, hydroxylated modified soybean oil, and dispersant to a mixer and mix at a stirring speed of 200-500 rpm for 3-8 minutes; then add activated calcium carbonate and 5A activating powder and stir at a stirring speed of 300-600 rpm for 5-10 minutes; finally add heavy calcium carbonate powder and maintain the stirring speed at 300-600 rpm for 15-20 minutes to obtain a uniform slurry; S2. Vacuum dehydration treatment: Transfer the slurry obtained in step S1 to a vacuum-capable reaction vessel, heat it to 60-110℃ with stirring, and evacuate it to a vacuum degree below ~0.08 MPa, and maintain this condition for 1-3 hours.

9. The preparation method according to claim 8, characterized in that: In step S1, the heavy calcium carbonate powder is added in 5 portions, with 110 to 130 portions added each time.

10. The preparation method according to claim 8, characterized in that: In step S2, the temperature of the vacuum dehydration treatment is 80~100℃, the vacuum degree is less than ~0.09 MPa, and the treatment time is 1.5~2.5 hours.

Images