A bio-based high-strength solvent-resistant hyperbranched adhesive and its preparation method

Abstract

The present invention discloses a bio-based high-strength solvent-resistant hyperbranched adhesive and a preparation method thereof, belonging to the field of bonding technology. The present invention prepares a hyperbranched polymer containing rich amino functional groups by deamination polycondensation reaction, and crosslinks it with glycerol triglycidyl ether through addition to obtain the high-strength, solvent-resistant bio-based hyperbranched adhesive MDUG adhesive of the present invention. The adhesive prepared by the present invention is widely applicable to bonding various materials, has high bonding strength and good solvent resistance, and the bonded substrate can also maintain its stability in extremely cold or high temperature environments (-196°C to 100°C), and adopts a simple solvent-free synthesis method, is easy to operate, and has low cost.

Description

Technical Field

[0001] The present invention belongs to the field of material science and engineering application technology, and in particular relates to a bio-based high-strength solvent-resistant hyperbranched adhesive and a preparation method thereof. Background Art

[0002] Adhesives play a vital role in our daily lives and in industry. Traditional petrochemical adhesives face challenges such as volatile organic compound (VOC) emissions, health concerns, and reliance on finite fossil resources. Bio-based adhesives offer a promising alternative for reducing environmental impact, as they are more sustainable.

[0003] However, despite their potential, bio-based adhesives generally suffer from low bonding strength and poor tolerance to harsh environmental conditions, which limits their widespread application. A common approach to improving their performance is to mimic natural organisms by constructing multiple interactions to enhance cohesion within the adhesive and bonding strength at the interface. These strategies include: molecular-level strategies such as electrostatic interactions, hydrogen bonds, π-π stacking, chain entanglement, and covalent bonds; and micro-scale strategies such as phase separation, mineral reinforcement, and interface topology. However, designing adhesives with hierarchical structures that provide reliable bonding strength under extreme temperatures or in the presence of solvents while maintaining compatibility with different surfaces remains a major challenge.

[0004] In summary, we have developed a new solvent-free bio-based adhesive with high bond strength and excellent durability under extreme environmental conditions, suitable for a variety of extreme environments.

[0005] Currently, there is a lack of a bio-based high-strength solvent-resistant hyperbranched adhesive and a preparation method thereof. Summary of the Invention

[0006] The object of the present invention is to provide a bio-based high-strength solvent-resistant hyperbranched adhesive and a preparation method thereof.

[0007] In order to solve the problems of the prior art, the present invention provides the following technical solutions:

[0008] In a first aspect, the present application provides a method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive.

[0009] In a second aspect, the present application provides a bio-based high-strength solvent-resistant hyperbranched adhesive.

[0010] In a third aspect, the present application provides a method for using a bio-based high-strength solvent-resistant hyperbranched adhesive.

[0011] In a fourth aspect, the present application provides an application of a bio-based high-strength solvent-resistant hyperbranched adhesive in a substrate.

[0012] The first aspect of the present application provides a method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive, comprising the following steps: (1) placing melamine and 5,5'-methylenedifurfurylamine in a molar ratio of 1:4 in a round-bottom flask, adding ammonium chloride, stirring in an oil bath at 200°C for 12 hours, and using a water trap to absorb the generated ammonia to obtain an amino-terminated hyperbranched polymer MD;

[0013] (2) After MD is obtained, the temperature is lowered to 115°C and urea is added to obtain an amino-terminated hyperbranched polymer MDU;

[0014] (3) The amino-terminated hyperbranched polymer MDU obtained in step (2) was mixed with propylene glycol triglycidyl ether in a mass ratio of 1:1.5. The propylene glycol triglycidyl ether was purchased as an industrial-grade chemical from Wuhan Smack Biotechnology Co., Ltd. and stirred evenly at room temperature to form a viscous colloid, thereby obtaining a bio-based high-strength, solvent-resistant hyperbranched adhesive, namely MDUG adhesive.

[0015] Furthermore, in step (1), the mass of ammonium chloride accounts for 6% of the mass of melamine.

[0016] Furthermore, in step (2), the molar ratio of melamine to 5,5'-methylenebisfurfurylamine and urea is 1:4:1 to 1:4:3.

[0017] A second aspect of the present application provides a bio-based high-strength solvent-resistant hyperbranched adhesive prepared by a method of using the bio-based high-strength solvent-resistant hyperbranched adhesive.

[0018] The third aspect of the present application provides a method for using a bio-based high-strength solvent-resistant hyperbranched adhesive, comprising the following steps: using the adhesive to overlap metal and non-metal materials, and then performing a curing treatment to achieve bonding.

[0019] Furthermore, in the curing conditions, the curing temperature is 160-180° C., and the curing time is 30-50 min.

[0020] A fourth aspect of the present application provides an application of a bio-based high-strength solvent-resistant hyperbranched adhesive in a substrate.

[0021] Beneficial effects: The preparation method of the present invention is simple: it adopts a solvent-free synthesis method, is simple to operate, has low cost, and is easy to industrialize.

[0022] Compared with the prior art, the present invention has the following advantages: (1) High strength and solvent resistance: The bio-based hyperbranched adhesive MDUG prepared by the present invention has high strength and good solvent resistance, can maintain stability at extreme temperatures (-196°C to 100°C), and is suitable for bonding a variety of materials.

[0023] (2) Environmentally friendly: As a bio-based adhesive, MDUG reduces dependence on petrochemical resources and reduces volatile organic compound (VOC) emissions, making it more environmentally friendly. Enhanced cohesion and interfacial bonding strength: By building multiple interactions such as hydrogen bonding, π-π stacking, covalent bonding, and chain entanglement, the cohesion within the adhesive and the bonding strength at the interface are enhanced.

[0024] (3) Excellent durability: MDUG adhesive maintains its integrity and exhibits excellent performance under extreme environmental conditions, such as solvents and a wide temperature range. High bond strength: The bond strength on steel is as high as 42.28 MPa and the bond strength on polytetrafluoroethylene is as high as 2.31 MPa, demonstrating excellent bonding performance.

[0025] (4) Good compatibility: The adhesive is designed with a layered structure to provide reliable bonding strength in extreme temperatures or the presence of solvents while maintaining compatibility with different surfaces. Wide range of applications: MDUG adhesives are suitable for bonding metal materials and non-metallic materials such as stainless steel, aluminum, copper, bamboo, wood, glass, polytetrafluoroethylene, etc., and have a wide range of application prospects.

[0026] (5) Multiple interactions enhance interfacial bonding: Cationic interactions, mechanical interlocking, and metal coordination interactions enhance bonding at the interface and improve bond strength. Suitable for harsh environments: Due to its excellent durability under extreme conditions, MDUG adhesives are suitable for spacecraft, ships, and other extreme industrial applications, representing a significant advancement in bio-based adhesives. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0028] Figure 1 is a flow chart for preparing the adhesive of the present invention;

[0029] Figure 2 Prepare a schematic diagram for the present invention. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0031] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0032] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0033] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0034] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0035] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components in the examples of this application is proportionally enlarged or reduced according to the content of the relevant components in the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0036] The terms "first" and "second" are used solely for descriptive purposes to distinguish objects, such as substances, from one another and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. For example, a first XX could also be referred to as a second XX, and similarly, a second XX could also be referred to as a first XX, without departing from the scope of the embodiments of this application. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0037] A first aspect of an embodiment of the present application provides a method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive, comprising the following steps: (1) placing melamine and 5,5'-methylenedifurfurylamine in a molar ratio of 1:4 in a round-bottom flask, adding ammonium chloride, stirring in an oil bath at 200°C for 12 hours, and using a water trap to absorb the generated ammonia gas to obtain an amino-terminated hyperbranched polymer MD;

[0038] (2) After MD is obtained, the temperature is lowered to 115°C and urea is added to obtain an amino-terminated hyperbranched polymer MDU;

[0039] (3) The MDU obtained in step (2) and propylene glycol triglycidyl ether are mixed at a mass ratio of 1:1.5 at room temperature to form a viscous colloid, thereby preparing a bio-based high-strength solvent-resistant hyperbranched adhesive.

[0040] In some embodiments, in step (1), the mass of ammonium chloride accounts for 6% of the mass of melamine.

[0041] In some embodiments, in step (2), the molar ratio of melamine to 5,5'-methylenebisfurfurylamine and urea is 1:4:1 to 1:4:3.

[0042] A second aspect of the embodiments of the present application provides a bio-based high-strength solvent-resistant hyperbranched adhesive prepared by a method of using the bio-based high-strength solvent-resistant hyperbranched adhesive.

[0043] A third aspect of an embodiment of the present application provides a method for using a bio-based, high-strength, solvent-resistant hyperbranched adhesive, comprising the following steps: overlapping metal and non-metal materials with the adhesive, and then performing a curing treatment to achieve bonding.

[0044] In some embodiments, the curing conditions include a curing temperature of 160-180° C. and a curing time of 30-50 min.

[0045] A fourth aspect of the embodiments of the present application provides an application of a bio-based high-strength solvent-resistant hyperbranched adhesive in a substrate.

[0046] Example 1

[0047] The present invention provides a method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive, comprising the following steps: (1) placing melamine and 5,5'-methylenedifurfurylamine in a molar ratio of 1:4 in a round-bottom flask, adding ammonium chloride (6% by mass of melamine), stirring in an oil bath at 200° C. for 12 h, and using a water trap to absorb generated ammonia to obtain an amino-terminated hyperbranched polymer MD.

[0048] (2) After MD is obtained, the temperature is lowered to 115° C., and urea is added so that the molar ratio of melamine to 5,5′-methylenebisfurfurylamine and urea is 1:4:1 to obtain an amino-terminated hyperbranched polymer MDU.

[0049] (3) uniformly mixing the amino-terminated hyperbranched polymer MDU obtained in step (2) with propylene glycol triglycidyl ether in a mass ratio of 1:1.5 to obtain a viscous colloid, which is the MDUG adhesive;

[0050] (4) The MDG adhesive obtained in step (2) was evenly applied to the surface of the substrate (10*25mm), the bonding area was overlapped, fixed with a clamp, and placed at 180°C for 50 minutes to achieve substrate overlap.

[0051] Example 2

[0052] The method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive of the present invention comprises the following steps:

[0053] (1) Melamine and 5,5'-methylenedifurfurylamine were placed in a round-bottom flask at a molar ratio of 1:4, and ammonium chloride (6% of the mass of melamine) was added. The mixture was stirred in an oil bath at 200°C for 12 h, and a water trap was used to absorb the generated ammonia gas to obtain an amino-terminated hyperbranched polymer MD.

[0054] (2) The amino-terminated hyperbranched polymer MD and propylene glycol triglycidyl ether are uniformly mixed in a mass ratio of 1:1.5 to obtain a viscous colloid, which is the MDG adhesive.

[0055] (3) The MDG adhesive obtained in step (2) was evenly applied to the surface of the substrate (10*25mm), the bonding area was overlapped, fixed with a clamp, and placed at 180°C for 50 minutes to achieve substrate overlap.

[0056] The adhesive prepared in Comparative Example 2 was used to bond the iron sheet. The bonding method and bonding strength were tested for bonding to substrates made of stainless steel, aluminum, copper, bamboo, wood, glass, and polytetrafluoroethylene. The solvent resistance and wide temperature applicability range of Example 2 were also tested.

[0057] Example 3

[0058] The difference between Example 3 and Example 1 is that in step (2), after MD is obtained, the temperature is lowered to 115°C and urea is added so that the molar ratio of melamine to 5,5'-methylenebisfurfurylamine and urea is 1:4:2 to obtain an amino-terminated hyperbranched polymer MDU.

[0059] Example 4

[0060] The difference between Example 4 and Example 1 is that in step (2), after MD is obtained, the temperature is lowered to 115°C and urea is added so that the molar ratio M:D:U of melamine, 5,5'-methylenebisfurfurylamine and urea is 1:4:3 to obtain an amino-terminated hyperbranched polymer MDU.

[0061] Example 5

[0062] The present invention discloses a method for using a bio-based, high-strength, solvent-resistant hyperbranched adhesive, comprising the steps of: overlapping metal and non-metal materials with the adhesive, followed by curing to achieve bonding. The curing conditions include a curing temperature of 180°C and a curing time of 50 minutes.

[0063] A fourth aspect of the embodiments of the present application provides an application of a bio-based high-strength solvent-resistant hyperbranched adhesive in a substrate.

[0064] Example 6

[0065] The difference between Example 6 and Example 5 is that in the curing conditions, the curing temperature is 160° C. and the curing time is 30 minutes.

[0066] Example 7

[0067] The difference between Example 7 and Example 5 is that in the curing conditions, the curing temperature is 170° C. and the curing time is 40 minutes.

[0068] Test Example 1

[0069] The performance test of the MDUG adhesive prepared in Example 1 was carried out as follows:

[0070] (1) Bonding performance test

[0071] The MDUG adhesive prepared in Example 1 was used to bond stainless steel, aluminum, copper, bamboo, wood, glass, and polytetrafluoroethylene substrates, and the bonding strength was tested. The bonding strength test results are shown in Table 1. The bonding data show that the MDUG adhesive has good adhesion to the various substrates, with the highest bonding strength of approximately 42.28 MPa to stainless steel.

[0072] (2) Solvent resistance test

[0073] The bond strength of the stainless steel samples bonded in Example 1 was tested after immersion in water, 10% NaOH solution, 10% NaCl solution, 10% H2SO4 solution, ethanol, ethyl acetate, petroleum ether, and dichloromethane for one and seven days, respectively. The results, shown in Table 2, demonstrate excellent water resistance. After one day of immersion in water, the bond strength of the stainless steel substrate reached 34.42 MPa. After seven days of immersion, the bond strength decreased the most in the 10% H2SO4 solution, but still retained 23% of its original strength.

[0074] (3) Performance testing over a wide temperature range

[0075] The stainless steel samples bonded in Example 1 were placed at -196°C, -80°C, -40°C, -18°C, 0°C, 25°C, 60°C, 80°C, and 100°C for 2 hours, and the bonding strength was tested. The MDUG adhesive exhibited good applicability within the -196°C to 100°C temperature range.

[0076] Test Example 2

[0077] The adhesion performance of Examples 1 and 2 on various substrates is shown in Table 1. Example 1 exhibited superior adhesion to various substrates compared to Example 2, attributed to the addition of urea, which enhances the rigidity of the polymer segments and thus improves cohesive strength. Furthermore, mechanical interlocking and various non-covalent interactions between the adhesive and the substrate surface play a key role in firmly bonding them together. In solvent resistance testing (Table 2), the adhesives in the examples demonstrated excellent resistance to solvent corrosion, primarily due to their extensive crosslinking and conjugated structure, which promotes a close alignment of the molecular segments and acts as a protective barrier.

[0078] The results in Table 3 show that both MDG and MDUG adhesives exhibit impressive stability over a range of temperatures (operating range: -196°C to 100°C) and provide excellent bonding performance, meeting the needs of numerous practical applications.

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083] Table 3

[0084]

[0085]

[0086] The basic principles, main features and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims, the description and their equivalents.

Claims

1. A method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive, characterized in that The steps include: (1) Melamine and 5,5'-methylenedifurfurylamine were placed in a round-bottom flask at a molar ratio of 1:4, ammonium chloride was added, and the mixture was stirred in an oil bath at 200°C for 12 h. The generated ammonia gas was absorbed using a water trap to obtain an amino-terminated hyperbranched polymer MD. (2) After obtaining the amino-terminated hyperbranched polymer MD, the temperature was lowered to 115° C., and urea was added to obtain the amino-terminated hyperbranched polymer MDU; (3) The amino-terminated hyperbranched polymer MDU obtained in step (2) and propylene glycol triglycidyl ether are stirred at room temperature in a mass ratio of 1:1.5 to form a viscous colloid, thereby preparing a bio-based high-strength solvent-resistant hyperbranched adhesive.

2. The method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive according to claim 1, wherein: In step (1), the mass of the ammonium chloride accounts for 6% of the mass of the melamine.

3. The method for preparing a bio-based high-strength solvent-resistant hyperbranched adhesive according to claim 1, wherein: In step (2), the molar ratio of melamine to 5,5'-methylenebisfurfurylamine and urea is 1:4:1 to 1:4:

3.

4. A bio-based high-strength solvent-resistant hyperbranched adhesive prepared by the method for using the bio-based high-strength solvent-resistant hyperbranched adhesive according to claim 1 or 2.

5. A method for using a bio-based high-strength solvent-resistant hyperbranched adhesive, characterized in that The method comprises the following steps: using the adhesive according to claim 1 to overlap metal and non-metal materials, and then performing a curing treatment to achieve bonding.

6. The method for using the bio-based high-strength solvent-resistant hyperbranched adhesive according to claim 5, characterized in that: Among the curing conditions, the curing temperature is 160-180° C., and the curing time is 30-50 minutes.

7. Use of the bio-based high-strength solvent-resistant hyperbranched adhesive according to claim 1 in a substrate.

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