A hot melt adhesive, its preparation method and application

Abstract

This invention provides a hot melt adhesive, its preparation method, and its application. The raw materials for preparing the hot melt adhesive include hyperbranched polyether copolymers and polyphenolic compounds. This invention prepares the hot melt adhesive by mixing the hyperbranched polyether copolymer and the polyphenolic compound and then heating the mixture. The preparation process is simple, and the hot melt adhesive exhibits excellent adhesion strength, good reusability, and water resistance to various substrates.

Description

Technical Field

[0001] This invention belongs to the field of adhesive materials technology, specifically relating to a hot melt adhesive, its preparation method, and its application. Background Technology

[0002] Hot melt adhesives are an important class of adhesive materials widely used in our daily lives and industries, such as automotive, electronic materials, and packaging materials. Hot melt adhesives achieve very high adhesion strength in a short time after cooling, making them suitable for complex applications. Furthermore, hot melt adhesives offer advantages such as good adhesion to various substrates, being solvent-free, non-toxic, and easy to use.

[0003] Supramolecular hot melt adhesives are cross-linked based on the non-covalent interactions of small molecules or polymers, exhibiting high adhesive strength and multiple reusability, making them very attractive adhesive materials. Among them, polyphenols inspired by mussels are widely used in the preparation of supramolecular hot melt adhesives. The catechol groups on polyphenols can self-assemble with small molecules or polymers to form supramolecular polymers and attach to the surface of inorganic materials through non-covalent interactions, such as metal coordination bonds, hydrogen bonds, or π-π stacking.

[0004] CN113308207A discloses a water-repellent TPU hot melt adhesive film and its preparation method. The raw materials for preparing the water-repellent TPU hot melt adhesive film include the following components by weight: 40-60 parts by weight of polyether polyol, 30-50 parts by weight of isocyanate, 10-15 parts by weight of chain extender, 1-10 parts by weight of organic fluorine waterproofing agent, 1-3 parts by weight of crosslinking agent, and 6-10 parts by weight of natural polyphenols. The TPU hot melt adhesive film prepared by this method has excellent water-repellent properties, but its adhesion strength needs further improvement, and it is not recyclable.

[0005] CN114250053A discloses a method for preparing and using a polyphenol-polyethylene glycol-based eutectic adhesive, wherein the eutectic adhesive is formed by the interaction of polyphenols and polyethylene glycol or polyethylene glycol derivatives through hydrogen bonding. The polyphenol-polyethylene glycol-based eutectic adhesive provided by this technical solution exhibits high adhesion strength and maintains good adhesion performance even in a liquid nitrogen atmosphere (-80℃). However, its water resistance is not significantly improved; if exposed to a humid or damp environment for a prolonged period, the adhesion strength decreases due to the weakening of non-covalent interactions between the composite materials.

[0006] Therefore, it is necessary to develop a hot melt adhesive with high bonding strength and good water resistance. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a hot melt adhesive, its preparation method, and its application. The hot melt adhesive is prepared by hyperbranched polyether copolymers and polyphenolic compounds, and features high bonding strength and good water resistance.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a hot melt adhesive, wherein the raw materials for preparing the hot melt adhesive include hyperbranched polyether copolymers and polyphenolic compounds.

[0010] In this invention, the hyperbranched polyether copolymer has a highly flexible polyether backbone and good biocompatibility. In addition, it has a unique three-dimensional structure and multiple functional hydroxyl groups. The polyphenolic compound can complex or crosslink with the polymer chain under non-covalent and covalent bonds. The supramolecular polymer formed by the self-assembly of the hyperbranched polyether copolymer and the polyphenolic compound has high adhesive strength and good water resistance.

[0011] Preferably, the mass ratio of the hyperbranched polyether copolymer to the polyphenol compound is 1-10:5, such as 1:5, 2:5, 3:5, 4:5, 5:5, 6:5, 7:5, 8:5, 9:5 or 10:5.

[0012] Preferably, the raw materials for preparing the hyperbranched polyether copolymer include glycidyl ether and optional epoxy alkane.

[0013] In this invention, when the raw materials for preparing the hyperbranched polyether copolymer include glycidyl ether and epoxy alkane, hydrophobic units are introduced into the polyether backbone of the hyperbranched polyether copolymer. The ether units in the obtained hyperbranched polyether copolymer act as hydrogen bond acceptors, and the alkane in the side chain acts as a hydrophobic structure, self-assembling with polyphenolic compounds to form a hot melt adhesive, thereby improving the bonding strength and water resistance.

[0014] Preferably, the epoxide includes any one or a combination of at least two of propylene oxide, butane oxide, pentane oxide, or hexane oxide.

[0015] Preferably, the molar ratio of glycidyl ether to alkylene oxide is 25:0-50, such as 25:0, 25:5, 25:10, 25:20, 25:25, 25:30, 25:35, 25:40, 25:45 or 25:50, and more preferably 25:2.5-35.

[0016] In this invention, the molar ratio of glycidyl ether to epoxy alkane is 25:0-50. If the molar ratio of glycidyl ether to epoxy alkane is too large, the hydrophobicity of the obtained hyperbranched polyether copolymer will be weakened.

[0017] Preferably, the number average molecular weight of the hyperbranched polyether copolymer is 500-20000 g / mol, such as 500 g / mol, 1000 g / mol, 5000 g / mol, 8000 g / mol, 10000 g / mol, 15000 g / mol, 18000 g / mol, or 20000 g / mol.

[0018] Preferably, the hyperbranched polyether copolymer is prepared by the following method: mixing glycidyl ether, epoxy alkane, catalyst and solvent, and reacting to obtain the hyperbranched polyether copolymer.

[0019] Preferably, the catalyst comprises a Lewis acid catalyst.

[0020] Preferably, the Lewis acid catalyst comprises scandium trifluoromethanesulfonate.

[0021] Preferably, the solvent includes any one or a combination of at least two of dichloromethane (CH2Cl2), chloroform (CHCl3), or acetonitrile (CH3CN).

[0022] Preferably, the reaction is carried out under the protection of an inert gas.

[0023] Preferably, the reaction temperature is room temperature and the reaction time is 5-10 hours, such as 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours or 10 hours.

[0024] Preferably, the reaction further includes quenching with a quenching agent and removing impurities.

[0025] Preferably, the quenching agent includes any one or a combination of at least two of water (H2O), methanol (CH3OH), or ethanol (CH3CH2OH).

[0026] Preferably, the impurity removal includes filtration, vacuum distillation, precipitation, and drying.

[0027] Preferably, the precipitation is achieved by adding a precipitant.

[0028] Preferably, the precipitant comprises a mixture of methanol and n-hexane.

[0029] Preferably, the mass ratio of methanol to n-hexane is 1:10-50, such as 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50.

[0030] Preferably, the drying is vacuum drying.

[0031] Preferably, the polyphenolic compound is a compound having the following structure.

[0032]

[0033] Wherein, each of R1 is independently selected from H or OH, and at least two of them are OH, and R2 is selected from amino, hydroxyl, carboxyl, hydrogen, halogen or C1-C60 (e.g. C1, C5, C10, C12, C15, C20, C25, C28, C30, C35, C38, C40, C42, C45, C48, C50, C55 or C60 etc.) organic groups.

[0034] Preferably, the organic groups of the C1-C60 are substituted or unsubstituted alkyl groups of C1-C60 (e.g., C1, C5, C10, C12, C15, C20, C25, C28, C30, C35, C38, C40, C42, C45, C48, C50, C55, or C60, etc.), or substituted or unsubstituted C3-C60 (e.g., C3, C5, C10, C12, C15, C20, C25, C28, C40, C50, C60 ... 30, C35, C38, C40, C42, C45, C48, C50, C55, or C60, etc.) cycloalkyl, substituted or unsubstituted C2-C60 (e.g., C2, C5, C10, C12, C15, C20, C25, C28, C30, C35, C38, C40, C42, C45, C48, C50, C55, or C60, etc.) alkenyl, substituted or unsubstituted C2-C60 (e.g., C2, C ... Alkyne groups of C5-C60 (e.g., C5, C10, C12, C15, C20, C25, C28, C30, C35, C38, C40, C42, C45, C48, C50, C55, or C60), and substituted or unsubstituted aryl groups of C5-C60 (e.g., C5, C10, C12, C15, C20, C25, C28, C30, C35, C38, C40, C42, C45, C48, C50, C55, or C60, etc.). The heteroaryl group is a C5-C60 group (e.g., C5, C10, C12, C15, C20, C25, C28, C30, C35, C38, C40, C42, C45, C48, C50, C55, or C60, etc.) that has been substituted or unsubstituted; when the group has substituents, the substituents are selected from halogens, cyano groups, ester groups, carbonyl groups, hydroxyl groups, aldehyde groups, carboxyl groups, ether groups, amino groups, nitro groups, sulfonyl groups, sulfonic acid groups, isocyanate groups, or silicon-containing groups.

[0035] Preferably, the polyphenolic compound includes any one or a combination of at least two of tannic acid, catechol, dopamine, gallic acid, or ellagic acid.

[0036] In a second aspect, the present invention provides a method for preparing a hot melt adhesive as described in the first aspect, the method comprising the following steps: mixing a hyperbranched polyether copolymer and a polyphenolic compound, heating, to obtain the hot melt adhesive.

[0037] Preferably, the heating temperature is 60-100℃, such as 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0038] Preferably, the heating time is 2-20 minutes, such as 2 minutes, 5 minutes, 8 minutes, 10 minutes, 12 minutes, 14 minutes, 15 minutes, 17 minutes, 19 minutes, or 20 minutes.

[0039] Thirdly, the present invention provides an adhesive material comprising the hot melt adhesive as described in the first aspect.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] This invention provides a hot melt adhesive prepared by heating a mixture of hyperbranched polyether copolymer and polyphenolic compound. The preparation process is simple. The hot melt adhesive exhibits excellent bonding strength and good reusability to various substrates. Even after long-term water immersion testing, it maintains high bonding strength and good water resistance; preferably, the bonding strength remains essentially unchanged, demonstrating excellent water resistance. The hot melt adhesive has a bonding strength of 0.75-2.15 MPa to glass and 0.91-2.37 MPa to iron. Preferably, after immersion in water for 48 hours, the bonding strength change rate of the hot melt adhesive is -1.4% to -1.1%. Attached Figure Description

[0042] Figure 1 It is the hyperbranched polyether copolymer provided in Example 4. 1 H NMR spectrum;

[0043] Figure 2 It is the hyperbranched polyether copolymer provided in Example 5. 1 H NMR spectrum;

[0044] Figure 3 These are illustrations showing the effect of hot melt adhesive bonding different substrates provided in Example 1. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] The sources of some components in the examples and comparative examples are as follows:

[0047] 1,2-Epoxybutane, CAS No. 106-88-7, was redistilled after reflux in calcium hydride for 8 hours and used. It was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0048] Propylene oxide: CAS No. 75-56-9, refluxed in calcium hydride for 8 hours and then redistilled before use, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0049] Hexane oxide: 1,2-epoxyhexane, CAS No. 1436-34-6, was refluxed in calcium hydride for 8 hours and then redistilled before use. It was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0050] Glycerin: CAS No. 556-52-5, refluxed in calcium hydride for 8 hours and then redistilled before use, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0051] Tannic acid: CAS No. 1401-55-4, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0052] Scandium trifluoromethanesulfonate: CAS No. 144026-79-9, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0053] Example 1

[0054] This embodiment provides a hot melt adhesive and its preparation method. The hot melt adhesive preparation method is as follows: 5g of hyperbranched polyether copolymer and 5g of tannic acid are mixed and stirred evenly, heated at 85°C for 10min, and then cooled to 25°C to obtain the hot melt adhesive.

[0055] The above hyperbranched polyether copolymer was prepared by the following method:

[0056] In a 10 mL Schlenk tube equipped with a magnetic stirrer, 0.5 mmol of scandium trifluoromethanesulfonate, 2 mL of CH2Cl2, 25 mmol of glycidyl ether, and 25 mmol of 1,2-epoxybutane were added sequentially. The mixture was stirred and reacted at room temperature for 8 h. After the reaction was completed, methanol was added to quench the reaction. The reaction solution was filtered to remove the catalyst, and the solvent was removed by vacuum distillation. The resulting colorless, viscous oil was precipitated in a mixture of methanol and n-hexane (methanol to n-hexane mass ratio of 1:10). The product was dried under vacuum at 65 °C overnight to obtain the hyperbranched polyether copolymer.

[0057] The yield of the hyperbranched polyether copolymer was 80%, and the number average molecular weight was 1800 g / mol.

[0058] Example 2

[0059] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that in the preparation of the hyperbranched polyether copolymer, the amount of 1,2-epoxybutane added is 17.5 mmol, the yield of the hyperbranched polyether copolymer is 83%, and the number average molecular weight is 1800 g / mol. Other raw materials, dosages, and preparation methods are the same as in Example 1.

[0060] Example 3

[0061] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Embodiment 1 is that in the preparation of the hyperbranched polyether copolymer, the amount of 1,2-epoxybutane added is 10 mmol, the yield of the hyperbranched polyether copolymer is 85%, and the number average molecular weight is 1800 g / mol. Other raw materials, dosages, and preparation methods are the same as in Embodiment 1.

[0062] Example 4

[0063] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that in the preparation of the hyperbranched polyether copolymer, the amount of 1,2-epoxybutane added is 2.5 mmol, the yield of the hyperbranched polyether copolymer is 85%, and the number average molecular weight is 1800 g / mol. Other raw materials, dosages, and preparation methods are the same as in Example 1.

[0064] Example 5

[0065] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that 1,2-epoxybutane is not added in the preparation of the hyperbranched polyether copolymer. The yield of the hyperbranched polyether copolymer is 90%, and the number average molecular weight is 1800 g / mol. Other raw materials, dosages, and preparation methods are the same as in Example 1.

[0066] Example 6

[0067] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that in the preparation of the hyperbranched polyether copolymer, the amount of 1,2-epoxybutane added is 35 mmol, the yield of the hyperbranched polyether copolymer is 83%, and the number average molecular weight is 1800 g / mol. Other raw materials, dosages, and preparation methods are the same as in Example 1.

[0068] Example 7

[0069] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that in the preparation of the hyperbranched polyether copolymer, the amount of 1,2-epoxybutane added is 50 mmol, the yield of the hyperbranched polyether copolymer is 80%, and the number average molecular weight is 1800 g / mol. Other raw materials, dosages, and preparation methods are the same as in Example 1.

[0070] Example 8

[0071] This embodiment provides a hot melt adhesive and its preparation method. The hot melt adhesive preparation method is as follows: 5g of hyperbranched polyether copolymer and 5g of catechin are mixed and stirred evenly, heated at 60°C for 20min, and then cooled to 25°C to obtain the hot melt adhesive.

[0072] The above hyperbranched polyether copolymer was prepared by the following method:

[0073] In a 10 mL Schlenk tube equipped with a magnetic stirrer, 0.5 mmol of scandium trifluoromethanesulfonate, 2 mL of CH3CN, 25 mmol of glycidyl ether, and 25 mmol of 1,2-epoxyhexane were added sequentially. The mixture was stirred and reacted at room temperature for 10 h. After the reaction was completed, ethanol was added to quench the reaction. The reaction solution was filtered to remove the catalyst, and the solvent was removed by vacuum distillation. The resulting colorless, viscous oil was precipitated in a mixture of methanol and n-hexane (methanol to n-hexane mass ratio of 1:10). The product was dried under vacuum at 65 °C overnight to obtain the hyperbranched polyether copolymer.

[0074] The yield of the hyperbranched polyether copolymer was 90%, and the number average molecular weight was 2500 g / mol.

[0075] Example 9

[0076] This embodiment provides a hot melt adhesive and its preparation method. The hot melt adhesive preparation method is as follows: 5g of hyperbranched polyether copolymer and 5g of dopamine are mixed and stirred evenly, heated at 100°C for 2min, and then cooled to 25°C to obtain the hot melt adhesive.

[0077] The above hyperbranched polyether copolymer was prepared by the following method:

[0078] In a 10 mL Schlenk tube equipped with a magnetic stirrer, 0.5 mmol of scandium trifluoromethanesulfonate, 2 mL of CHCl3, 25 mmol of glycidyl ether, and 25 mmol of propylene oxide were added sequentially. The mixture was stirred and reacted at room temperature for 5 h. After the reaction was completed, ethanol was added to quench the reaction. The reaction solution was filtered to remove the catalyst, and the solvent was removed by vacuum distillation. The resulting colorless, viscous oil was precipitated in a mixture of methanol and n-hexane (methanol to n-hexane mass ratio of 1:50). The product was dried under vacuum at 65 °C overnight to obtain the hyperbranched polyether copolymer.

[0079] The yield of the hyperbranched polyether copolymer was 75%, and the number average molecular weight was 1600 g / mol.

[0080] Example 10

[0081] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that 1g of hyperbranched polyether copolymer and 5g of tannic acid are mixed. The other raw materials, dosages and preparation methods are the same as in Example 1.

[0082] Example 11

[0083] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that 10g of hyperbranched polyether copolymer and 5g of tannic acid are mixed. The other raw materials, dosages and preparation methods are the same as in Example 1.

[0084] Example 12

[0085] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that 0.5g of hyperbranched polyether copolymer and 5g of tannic acid are mixed. The other raw materials, dosages and preparation methods are the same as in Example 1.

[0086] Example 13

[0087] This embodiment provides a hot melt adhesive and its preparation method. The only difference between this embodiment and Example 1 is that 12g of hyperbranched polyether copolymer and 5g of tannic acid are mixed. The other raw materials, dosages and preparation methods are the same as in Example 1.

[0088] Comparative Example 1

[0089] This comparative example provides a hot melt adhesive and its preparation method. The hot melt adhesive preparation method is as follows: 5g of PEG-2000 and 5g of tannic acid are mixed and stirred evenly, heated at 85°C for 10min, and then cooled to 25°C to obtain the hot melt adhesive.

[0090] The bonding strength test is conducted using the following method.

[0091] The hot melt adhesives provided in the examples and comparative examples were heated to 85°C. Samples with dimensions of 100mm × 25mm were taken, and the substrate of the samples included any one of glass, iron, wood, PET, or PMMA. 20mg of hot melt adhesive was applied between two sample strips, and then the samples were bonded at 85°C. The bonding area was 25mm × 12.5mm, and a pressure of 1000Pa was applied for 10 minutes. The bond strength was tested using a universal tensile testing machine. During the tensile test, the tensile rate was 5mm / min. A complete test was performed when the two materials were completely separated. A total of 5 tests were conducted, and the average value was taken.

[0092] The water resistance test method for hot melt adhesives is as follows.

[0093] The hot melt adhesives provided in Examples 1, 4-13, and Comparative Example 1 were heated to 85°C. Iron samples with dimensions of 100mm × 25mm were taken, and 20mg of hot melt adhesive was applied between two sample strips. The samples were then bonded at 85°C, with a bonding area of ​​25mm × 12.5mm, under a pressure of 1000Pa for 10 minutes. The samples were then immersed in water for 48 hours, dried, and the bond strength was tested using a universal tensile testing machine. During the tensile test, the tensile rate was 5mm / min, and a complete test was performed until the two materials were completely separated. A total of 5 tests were conducted, and the average value was taken.

[0094] The test results are shown in Table 1.

[0095] Table 1

[0096]

[0097] In Table 1, "-" indicates that the test was not performed.

[0098] The reusability evaluation of hot melt adhesives is conducted using the following test methods.

[0099] The supramolecular hot melt adhesives prepared in Examples 4, 5, and Comparative Example 1 were heated to 85°C. Glass samples with dimensions of 100mm × 25mm were taken, and 20mg of hot melt adhesive was applied between two samples. The samples were then bonded at 85°C, with a bonding area of ​​25mm × 12.5mm, under a pressure of 1000Pa for 10 minutes. The bond strength was tested using a universal tensile testing machine at a tensile rate of 5mm / min. A complete test was performed when the two materials were completely separated; five tests were conducted, and the average value was taken. The separated materials were then rebonded at 85°C, with a bonding area of ​​25mm × 12.5mm, under a pressure of 1000Pa for 10 minutes. The bond strength was tested again using a universal tensile testing machine. This process was repeated six times.

[0100] The test results are shown in Table 2.

[0101] Table 2

[0102]

[0103] According to the results in Table 1, the hot melt adhesives provided in Examples 1-13 have a bonding strength of 0.75-2.15 MPa to glass and a bonding strength of 0.91-2.37 MPa to iron, indicating high bonding strength. The hot melt adhesives provided in Examples 1 and 3, when soaked in water for 48 hours, showed a bonding strength change rate of -1.4% to -1.1%, indicating good water resistance.

[0104] Figure 1 and Figure 2 The hyperbranched polyether copolymers synthesized in Examples 4 and 5 are respectively 1 The H NMR spectrum indicates that the hyperbranched polyether copolymer was successfully synthesized. Figure 3 This demonstrates that the hot melt adhesive exhibits good adhesion to various substrates.

[0105] A comparison of Examples 1-4 shows that, within a certain range, the bonding strength of the hot melt adhesive increases with the increase of the molar ratio of glycidyl ether and epoxy alkane.

[0106] Comparing Example 5 with Example 1, it can be seen that if 1,2-epoxybutane is not added in the preparation of the hyperbranched polyether copolymer, the bonding strength is improved, but the water resistance is reduced. This proves that the hot melt adhesive prepared by using a combination of glycidyl ether and epoxy alkane to prepare the hyperbranched polyether copolymer has better water resistance.

[0107] Comparing Example 7 with Example 1, it can be seen that if the amount of epoxy alkane added during the preparation of the hyperbranched polyether copolymer is too large, the adhesive strength of the prepared hot melt adhesive will be lower. This proves that the hot melt adhesive prepared by using a specific molar ratio of glycidyl ether and epoxy alkane to prepare the hyperbranched polyether copolymer has better performance.

[0108] Compared with Example 1, it can be seen that if the mass ratio of hyperbranched polyether copolymer to polyphenol compound is too small (Example 12), the adhesive strength of the prepared hot melt adhesive is low; if the mass ratio of hyperbranched polyether copolymer to polyphenol compound is too large (Example 13), the adhesive strength of the prepared hot melt adhesive is low. This proves that using a specific mass ratio of hyperbranched polyether copolymer to polyphenol compound results in a hot melt adhesive with better performance.

[0109] Compared with Example 1, it can be seen that if the hyperbranched polyether copolymer is replaced with polyethylene glycol (Comparative Example 1), the adhesive strength of the prepared hot melt adhesive will be lower and the water resistance will decrease.

[0110] According to the results in Table 2, the hot melt adhesive provided in Example 4 still maintains 82% of its bonding strength after being reused 6 times, and the hot melt adhesive provided in Example 5 still maintains 72% of its bonding strength after being reused 6 times. Compared with Examples 4 and 5, the hot melt adhesive provided in Comparative Example 1 maintains 68% of its bonding strength after being reused 6 times, which proves that the hot melt adhesive prepared by using hyperbranched polyether copolymer and polyphenolic compound has excellent reusability.

[0111] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A hot melt adhesive, characterized in that, The raw materials for preparing the hot melt adhesive include hyperbranched polyether copolymers and polyphenolic compounds; The raw materials for preparing the hyperbranched polyether copolymer include glycidyl ether and optional epoxy alkane. The hyperbranched polyether copolymer is prepared by the following method: glycidyl ether, epoxy alkane, catalyst and solvent are mixed and reacted to obtain the hyperbranched polyether copolymer.

2. The hot melt adhesive according to claim 1, characterized in that, The mass ratio of the hyperbranched polyether copolymer to the polyphenol compound is 1-10:

5.

3. The hot melt adhesive according to claim 1 or 2, characterized in that, The epoxide hydrocarbons include any one or a combination of at least two of propylene oxide, butane oxide, pentane oxide, or hexane oxide.

4. The hot melt adhesive according to claim 1, characterized in that, The molar ratio of glycidyl ether to alkyl epoxide is 25:0-50.

5. The hot melt adhesive according to claim 1, characterized in that, The molar ratio of glycidyl ether to alkyl epoxide is 25:2.5-35.

6. The hot melt adhesive according to claim 1, characterized in that, The number-average molecular weight of the hyperbranched polyether copolymer is 500-20000 g / mol.

7. The hot melt adhesive according to claim 1, characterized in that, The catalyst includes a Lewis acid catalyst.

8. The hot melt adhesive according to claim 7, characterized in that, The Lewis acid catalyst includes scandium trifluoromethanesulfonate.

9. The hot melt adhesive according to claim 1, characterized in that, The solvent includes any one or a combination of at least two of dichloromethane, trichloromethane, or acetonitrile.

10. The hot melt adhesive according to claim 1, characterized in that, The reaction is carried out under the protection of an inert gas.

11. The hot melt adhesive according to claim 1, characterized in that, The reaction was carried out at room temperature for 5-10 hours.

12. The hot melt adhesive according to claim 1, characterized in that, The reaction process also includes quenching with a quenching agent and removing impurities.

13. The hot melt adhesive according to claim 12, characterized in that, The quenching agent includes any one or a combination of at least two of water, methanol, or ethanol.

14. The hot melt adhesive according to claim 12, characterized in that, The impurity removal process includes filtration, vacuum distillation, precipitation, and drying.

15. The hot melt adhesive according to claim 14, characterized in that, The precipitate is formed by adding a precipitant.

16. The hot melt adhesive according to claim 15, characterized in that, The precipitant comprises a mixture of methanol and n-hexane.

17. The hot melt adhesive according to claim 16, characterized in that, The mass ratio of methanol to n-hexane is 1:10-50.

18. The hot melt adhesive according to claim 14, characterized in that, The drying process is vacuum drying.

19. The hot melt adhesive according to claim 1, characterized in that, The polyphenolic compounds are compounds having the following structure; Wherein, each of R1 is independently selected from H or OH, and at least two of them are OH, and R2 is selected from amino, hydroxyl, carboxyl, hydrogen, halogen or C1-C60 organic groups.

20. The hot melt adhesive according to claim 19, characterized in that, The C1-C60 organic groups are substituted or unsubstituted C1-C60 alkyl groups, substituted or unsubstituted C3-C60 cycloalkyl groups, substituted or unsubstituted C2-C60 alkenyl groups, substituted or unsubstituted C2-C60 alkynyl groups, substituted or unsubstituted C5-C60 aryl groups, and substituted or unsubstituted C5-C60 heteroaryl groups; when the groups have substituents, the substituents are selected from halogens, cyano groups, ester groups, carbonyl groups, hydroxyl groups, aldehyde groups, carboxyl groups, ether groups, amino groups, nitro groups, sulfonyl groups, sulfonic acid groups, isocyanate groups, or silicon-containing groups.

21. The hot melt adhesive according to claim 1, characterized in that, The polyphenolic compounds include any one or a combination of at least two of tannic acid, catechol, dopamine, gallic acid, or ellagic acid.

22. The method for preparing hot melt adhesive according to any one of claims 1-21, characterized in that, The preparation method includes the following steps: mixing hyperbranched polyether copolymer and polyphenol compound, heating to obtain the hot melt adhesive.

23. The method for preparing hot melt adhesive according to claim 22, characterized in that, The heating temperature is 60℃-100℃.

24. The method for preparing hot melt adhesive according to claim 22, characterized in that, The heating time is 2-20 minutes.

25. An adhesive material, characterized in that, The adhesive material includes the hot melt adhesive as described in any one of claims 1-21.

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