Matte matte hot melt adhesive for high-temperature hot-press bonding and preparation method thereof

Abstract

The invention relates to the technical field of hot melt adhesives, in particular to a matte matte hot melt adhesive for high-temperature hot-press bonding and a preparation method of the matte matte hot melt adhesive. The preparation method comprises the following steps: S1, carrying out vacuum dehydration on polyester polyol, polyether polyol and tackifying resin at 110-130 DEG C for 2-3 hours, cooling to 60-70 DEG C, adding diphenylmethane diisocyanate and dibutyltin dilaurate under the protection of nitrogen, reacting at 100-130 DEG C for 2-4 hours, cooling the temperature of a system to 90-95 DEG C, adding hydroxyl-terminated polydimethylsiloxane, continuously reacting for 1-2 hours, cooling to 90-95 DEG C, cooling to 90-95 DEG C, cooling to 90-95 DEG C, cooling to 90-95 DEG C, and carrying out heat preservation for 2-3 hours, so as to obtain a prepolymer; then carrying out vacuum bubble pumping until no bubble appears, so as to obtain the polyurethane hot melt adhesive; and S2, uniformly mixing the polyurethane hot melt adhesive, the polystyrene resin, the matte agent, the filler and the antioxidant, carrying out melt blending extrusion, granulating and drying to obtain the matte matte hot melt adhesive.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot melt adhesives, in particular to a matte-fog hot melt adhesive for high-temperature hot-press bonding and a preparation method thereof. BACKGROUND

[0002] With the development of industry and manufacturing, hot melt adhesives have been widely used in the assembly and bonding of various products, especially in the electronics, automotive and packaging industries. Hot melt adhesives gradually become an important bonding material due to their fast curing, environmental protection and strong adaptability. In recent years, the demand for high-temperature hot-press bonding has increased, which has increased the performance requirements of hot melt adhesives, especially their high-temperature resistance, adhesion and appearance quality.

[0003] In recent years, matte-fog hot melt adhesives have gradually attracted attention due to their elegant appearance and excellent touch. This type of hot melt adhesive not only has good bonding performance, but also exhibits a fascinating fog effect in optical properties, making it suitable for application in high-end consumer products and electronic product housings. However, there are still some technical problems in the process of high-temperature hot-press bonding in the existing technology, which need to be solved. Temperature adaptability is insufficient: the performance of existing hot melt adhesives in high-temperature environments is often unstable, prone to softening, flowing or degradation, resulting in a decrease in bonding strength. Insufficient adhesion: the adhesion of some hot melt adhesives under high-temperature hot-pressing does not meet the requirements, especially the bonding effect on complex material surfaces or low surface energy materials is not ideal. Appearance quality problems: traditional hot melt adhesives are prone to glossy or uneven appearance after curing, which cannot meet the demand for matte-fog, affecting the overall aesthetics of the product. Environmental friendliness: some chemical components used in hot melt adhesives may have a negative impact on the environment, and with the increasing strictness of environmental regulations, developing green and environmentally friendly hot melt adhesive materials has become a major challenge.

[0004] Therefore, we propose a matte-fog hot melt adhesive for high-temperature hot-press bonding and a preparation method thereof. SUMMARY

[0005] The purpose of the present application is to provide a matte-fog hot melt adhesive for high-temperature hot-press bonding and a preparation method thereof to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: A preparation method of a matte-fog hot melt adhesive for high-temperature hot-press bonding, comprising the following steps: Step S1: Dehydrate polyester polyol, polyether polyol and tackifying resin under vacuum at 110-130℃ for 2-3 hours, cool down to 60-70℃, add diphenylmethane diisocyanate and dibutyltin dilaurate under nitrogen protection, react at 100-130℃ for 2-4 hours, cool the system temperature to 90-95℃, add hydroxyl-terminated polydimethylsiloxane, continue the reaction for 1-2 hours, and then perform vacuum degassing until no bubbles appear to obtain polyurethane hot melt adhesive; Step S2: Mix polyurethane hot melt adhesive, polystyrene resin, matte agent, filler and antioxidant evenly, melt-blend and extrude, granulate, and dry to obtain matte hot melt adhesive.

[0007] Further, the polyurethane hot melt adhesive comprises the following components by weight: 20-40 parts polyester polyol, 30-50 parts polyether polyol, 10-20 parts tackifying resin, 60-80 parts diphenylmethane diisocyanate, 0.5-1.5 parts dibutyltin dilaurate, and 3-8 parts hydroxyl-terminated polydimethylsiloxane.

[0008] Furthermore, the preparation method of the tackifying resin is as follows: Step A: Under nitrogen protection, maleic rosin acid, epichlorohydrin and benzyltriethylammonium chloride are mixed evenly and reacted at 105-115℃ for 3-5 hours. The temperature is then lowered to 70-80℃, maleic anhydride and p-hydroxyanisole are added and mixed evenly. The mixture is reacted for 2-4 hours to obtain modified rosin. Step B: Mix the modified rosin and toluene evenly, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, react for 0.5-1.0 h, then add amino-terminated maleimide, and react at 50-60℃ for 5-7 h to obtain a compound containing double bonds. Step C: Mix the double bond compound, 1-thioglycerol and photoinitiator evenly, and then irradiate with ultraviolet light to obtain the tackifying resin.

[0009] Further, in step A, the modified rosin comprises the following components by weight: 10-20 parts of maleic astringent, 15-25 parts of epichlorohydrin, 0.03-0.05 parts of benzyltriethylammonium chloride, 5-10 parts of maleic anhydride, and 0.01-0.03 parts of p-hydroxyanisole.

[0010] Further, in step B, the mass ratio of the modified rosin, toluene, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide and amino-terminated maleimide is 1:(15-25):(0.1-0.3):(0.08-0.10):(2-4).

[0011] Furthermore, the preparation method of the amino-terminated maleimide is as follows: Under nitrogen protection, maleic anhydride and N,N'-dimethylformamide were mixed evenly, heated to 60-70℃, and a mixed solution of 2-(4-aminophenyl)-5-aminobenzimidazole and N,N'-dimethylformamide was added dropwise over 0.5-1.0 h. The reaction was allowed to proceed for 2-4 h, and the mixture was cooled to room temperature. After filtration, washing, and drying, an intermediate was obtained. Under nitrogen protection, the intermediate was mixed evenly with xylene, and p-toluenesulfonic acid and p-hydroxyanisole were added. The mixture was then refluxed at 100-110℃ for 5-7 h to separate water and cyclize and dehydrate. After rotary evaporation, filtration, washing, recrystallization, and drying, amino-terminated maleimide was obtained.

[0012] Further, the mass ratio of maleic anhydride to N,N'-dimethylformamide is 1:(10-12), and the mass ratio of 2-(4-aminophenyl)-5-aminobenzimidazole to N,N'-dimethylformamide is 1:(10-12).

[0013] Furthermore, the mass ratio of maleic anhydride to 2-(4-aminophenyl)-5-aminobenzimidazole is 1:(2.1-2.3).

[0014] Furthermore, the mass ratio of the intermediate, xylene, p-toluenesulfonic acid, and p-hydroxyanisole is 1:(4-6):(0.1-0.3):(0.01-0.02).

[0015] In the above technical solution, a rigid benzimidazole ring structure is introduced by amidation reaction of maleic anhydride with one end amino group of 2-(4-aminophenyl)-5-aminobenzimidazole. During the reaction, the mass ratio of maleic anhydride to 2-(4-aminophenyl)-5-aminobenzimidazole is precisely controlled to ensure that the other end amino group is retained, and finally an amino-terminated maleimide is obtained.

[0016] Further, in step C, the tackifying resin comprises the following components by weight: 10-20 parts of a compound containing double bonds, 15-30 parts of 1-thioglycerol, and 1-3 parts of a photoinitiator.

[0017] Further, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the ultraviolet irradiation process conditions are: irradiation wavelength 360-400 nm, irradiation time 20-60 min, and irradiation intensity 20-35 mW / cm². 2 .

[0018] Furthermore, the matte hot melt adhesive comprises the following components by weight: 80-90 parts of polyurethane hot melt adhesive, 10-20 parts of polystyrene resin, 20-40 parts of matting agent, 2-5 parts of filler, and 1-3 parts of antioxidant.

[0019] Furthermore, the filler is one or more of cryolite, calcium carbonate, wollastonite, talc, fumed silica, quartz sand, aluminum powder, and zinc powder.

[0020] Further, the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168 and 2,6-di-tert-butyl-4-methylphenol.

[0021] Furthermore, the matting agent is a mixture of EPDM rubber, nitrile rubber and SEBS in a mass ratio of 1:(3-5):(4-7).

[0022] Furthermore, the melt blending temperature is 150-200℃. Furthermore, the drying temperature is 70-80℃, and the drying time is 8-18 hours.

[0023] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a matte hot melt adhesive for high-temperature hot-press bonding and its preparation method. The method involves an epoxy ring-opening reaction between the carboxyl groups in maleic rosin acid and epichlorohydrin to generate hydroxyl groups. Maleic anhydride then reacts with these hydroxyl groups to introduce carbon-carbon double bonds and carboxyl groups, resulting in modified rosin. The carboxyl groups of the modified rosin react with amino-terminated maleimide to introduce a rigid benzene ring structure, exhibiting excellent heat resistance. Finally, the remaining double bonds in the modified rosin undergo a mercapto-olefin click reaction with 1-thioglycerol to obtain a tackifying resin rich in hydroxyl groups. This resin can participate in the polymerization of polyurethane molecules, improving the adhesion and heat resistance of the hot melt adhesive. Furthermore, because the tackifying resin is tightly bonded to the main polymer network through chemical bonds, it effectively "anchors" the filler to a stable matrix, preventing filler migration and aggregation during high-temperature processing or use, thus ensuring the uniformity and durability of the final matte finish. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, all parts below are by weight. It should be noted that there are no special restrictions on the suppliers of any of the raw materials involved in this invention. Exemplary examples include (in this embodiment): polyester polyol: brand BY-3113; polyether polyol: brand CP450, sourced from Dow Chemical; hydroxyl-terminated polydimethylsiloxane: Mn 1000, sourced from Shanghai Aladdin Biochemical Technology Co., Ltd.; filler: calcium carbonate, average particle size 4000-6000 mesh; polystyrene resin: brand Shanghai SECCO GPPS-123P; antioxidant: antioxidant 1010; EPDM rubber: brand Sinopec Mitsui EPDM 3092PM; nitrile rubber: model 1051, sourced from Dongguan Mingyuan Plastics Co., Ltd.; SEBS: hydrogenated styrene-butadiene-styrene block copolymer, brand Taiwan Rubber SEBS 6151.

[0026] Example 1: A method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding, comprising the following processes: Step S1: 20 parts of polyester polyol, 30 parts of polyether polyol and 10 parts of tackifying resin are vacuum dehydrated at 110°C for 2 hours, cooled to 60°C, and under nitrogen protection, 60 parts of diphenylmethane diisocyanate and 0.5 parts of dibutyltin dilaurate are added. The mixture is reacted at 100°C for 2 hours. The system temperature is then cooled to 90°C, 3 parts of hydroxyl-terminated polydimethylsiloxane are added, and the reaction continues for 1 hour. Then, vacuum degassing is performed until no bubbles appear, and polyurethane hot melt adhesive is obtained. Step S2: Mix 80 parts of polyurethane hot melt adhesive, 10 parts of polystyrene resin, 20 parts of matting agent (the matting agent is a mixture of EPDM rubber, nitrile rubber and SEBS in a mass ratio of 1:3:4), 2 parts of filler and 1 part of antioxidant evenly, melt blend and extrude (temperature is 150℃), granulate, and dry (drying temperature is 70℃, drying time is 18h) to obtain matte hot melt adhesive; The preparation method of the tackifying resin is as follows: Step A: Under nitrogen protection, 10 parts of maleic rosin acid, 15 parts of epichlorohydrin and 0.03 parts of benzyltriethylammonium chloride are mixed evenly and reacted at 105°C for 3 hours. The temperature is then lowered to 70°C, and 5 parts of maleic anhydride and 0.01 parts of p-hydroxyanisole are added and mixed evenly. The mixture is reacted for 2 hours to obtain modified rosin. Step B: Mix 10 parts of modified rosin and 150 parts of toluene evenly, add 1 part of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.8 parts of N-hydroxysuccinimide, react for 0.5 h, then add 20 parts of amino-terminated maleimide, react at 50 °C for 5 h to obtain a compound containing double bonds. Step C: Mix 10 parts of a compound containing double bonds, 15 parts of 1-thioglycerol, and 1 part of 2-hydroxy-2-methyl-1-phenyl-1-propanone thoroughly. After irradiation with ultraviolet light at a wavelength of 360 nm for 20 min, the mixture is then subjected to an irradiation intensity of 35 mW / cm². 2 This yields a tackifying resin; The preparation method of amino-terminated maleimide is as follows: Under nitrogen protection, 10 parts of maleic anhydride and 100 parts of N,N'-dimethylformamide were mixed evenly, heated to 60°C, and a mixed solution of 21 parts of 2-(4-aminophenyl)-5-aminobenzimidazole and 210 parts of N,N'-dimethylformamide was added dropwise over 0.5 h. The reaction was allowed to proceed for 2 h, and the mixture was cooled to room temperature. After filtration, washing, and drying, an intermediate was obtained. Under nitrogen protection, 20 parts of the intermediate and 80 parts of xylene were mixed evenly, and 2 parts of p-toluenesulfonic acid and 0.2 parts of p-hydroxyanisole were added. The mixture was refluxed at 100°C for 5 h to separate water and cyclize and dehydrate. After rotary evaporation, filtration, washing, recrystallization, and drying, amino-terminated maleimide was obtained.

[0027] Example 2: A method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding, comprising the following processes: Step S1: 30 parts of polyester polyol, 40 parts of polyether polyol and 15 parts of tackifying resin are vacuum dehydrated at 120°C for 2.5 h, cooled to 65°C, and under nitrogen protection, 70 parts of diphenylmethane diisocyanate and 1 part of dibutyltin dilaurate are added. The mixture is reacted at 120°C for 3 h, the system temperature is cooled to 92°C, 5 parts of hydroxyl-terminated polydimethylsiloxane are added, and the reaction is continued for 1.5 h. Then, vacuum degassing is performed until no bubbles appear to obtain polyurethane hot melt adhesive. Step S2: Mix 85 parts of polyurethane hot melt adhesive, 15 parts of polystyrene resin, 30 parts of matting agent (the matting agent is a mixture of EPDM rubber, nitrile rubber and SEBS in a mass ratio of 1:4:5), 4 parts of filler and 2 parts of antioxidant evenly, melt blend and extrude (temperature is 180℃), granulate, and dry (drying temperature is 75℃, drying time is 10h) to obtain matte hot melt adhesive; The preparation method of the tackifying resin is as follows: Step A: Under nitrogen protection, 15 parts of maleic rosin acid, 20 parts of epichlorohydrin and 0.04 parts of benzyltriethylammonium chloride are mixed evenly and reacted at 110°C for 4 hours. The temperature is then lowered to 75°C, and 8 parts of maleic anhydride and 0.02 parts of p-hydroxyanisole are added and mixed evenly. The mixture is reacted for 3 hours to obtain modified rosin. Step B: Mix 15 parts of modified rosin and 300 parts of toluene evenly, add 3 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.4 parts of N-hydroxysuccinimide, react for 0.8 h, then add 45 parts of amino-terminated maleimide, and react at 55 °C for 6 h to obtain a compound containing double bonds. Step C: Mix 15 parts of a compound containing double bonds, 25 parts of 1-thioglycerol, and 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone thoroughly. After irradiation with ultraviolet light at a wavelength of 380 nm for 40 min, the mixture is then subjected to an irradiation intensity of 30 mW / cm². 2 This yields a tackifying resin; The preparation method of amino-terminated maleimide is as follows: Under nitrogen protection, 21 parts of maleic anhydride and 230 parts of N,N'-dimethylformamide were mixed evenly, and the mixture was heated to 60-70℃. A mixed solution of 46.2 parts of 2-(4-aminophenyl)-5-aminobenzimidazole and 500 parts of N,N'-dimethylformamide was added dropwise over 0.8 h. The reaction was allowed to proceed for 3 h, and the mixture was cooled to room temperature. After filtration, washing, and drying, an intermediate was obtained. Under nitrogen protection, 45 parts of the intermediate and 225 parts of xylene were mixed evenly, and 9 parts of p-toluenesulfonic acid and 0.6 parts of p-hydroxyanisole were added. The mixture was refluxed at 105℃ for 6 h to separate water and cyclize and dehydrate. After rotary evaporation, filtration, washing, recrystallization, and drying, amino-terminated maleimide was obtained.

[0028] Example 3: A method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding, comprising the following processes: Step S1: 40 parts of polyester polyol, 50 parts of polyether polyol and 20 parts of tackifying resin are vacuum dehydrated at 130°C for 3 hours, cooled to 70°C, and under nitrogen protection, 80 parts of diphenylmethane diisocyanate and 1.5 parts of dibutyltin dilaurate are added. The mixture is reacted at 130°C for 4 hours. The system temperature is then cooled to 95°C, and 8 parts of hydroxyl-terminated polydimethylsiloxane are added. The reaction continues for 2 hours, and then vacuum degassing is performed until no bubbles appear, to obtain polyurethane hot melt adhesive. Step S2: Mix 90 parts of polyurethane hot melt adhesive, 20 parts of polystyrene resin, 40 parts of matting agent (the matting agent is a mixture of EPDM rubber, nitrile rubber and SEBS in a mass ratio of 1:5:4), 5 parts of filler and 3 parts of antioxidant evenly, melt blend and extrude (temperature is 200℃), granulate, and dry (drying temperature is 80℃, drying time is 8h) to obtain matte hot melt adhesive; The preparation method of the tackifying resin is as follows: Step A: Under nitrogen protection, 20 parts of maleic rosin acid, 25 parts of epichlorohydrin and 0.05 parts of benzyltriethylammonium chloride are mixed evenly and reacted at 115°C for 5 hours. The temperature is then lowered to 80°C, and 10 parts of maleic anhydride and 0.03 parts of p-hydroxyanisole are added and mixed evenly. The mixture is reacted for 4 hours to obtain modified rosin. Step B: Mix 20 parts of modified rosin and 500 parts of toluene evenly, add 6 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 2 parts of N-hydroxysuccinimide, react for 1.0 h, then add 80 parts of amino-terminated maleimide, and react at 60 °C for 7 h to obtain a compound containing double bonds. Step C: Mix 20 parts of a compound containing double bonds, 30 parts of 1-thioglycerol, and 3 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone thoroughly. After irradiation with ultraviolet light at a wavelength of 400 nm for 60 min, the mixture is then subjected to an irradiation intensity of 20 mW / cm². 2 This yields a tackifying resin; The preparation method of amino-terminated maleimide is as follows: Under nitrogen protection, 34 parts of maleic anhydride and 408 parts of N,N'-dimethylformamide were mixed evenly, heated to 70°C, and 78.2 parts of a mixed solution of 2-(4-aminophenyl)-5-aminobenzimidazole and 900 parts of N,N'-dimethylformamide were added dropwise over 1.0 h. The reaction was allowed to proceed for 4 h, and the mixture was cooled to room temperature. After filtration, washing, and drying, an intermediate was obtained. Under nitrogen protection, 80 parts of the intermediate and 480 parts of xylene were mixed evenly, and 24 parts of p-toluenesulfonic acid and 1.6 parts of p-hydroxyanisole were added. The mixture was refluxed at 110°C for 7 h to separate water and cyclize and dehydrate. After rotary evaporation, filtration, washing, recrystallization, and drying, amino-terminated maleimide was obtained.

[0029] Comparative Example 1: Comparative Example 1 is based on Example 2, except that 5 parts of tackifying resin are added. The remaining process steps and reaction parameters are the same as those in Example 2.

[0030] Comparative Example 2: Comparative Example 2 is based on Example 2, except that amino-terminated maleimide was not introduced in Comparative Example 2, and the remaining process steps and reaction parameters are the same as in Example 2. The preparation method of the tackifying resin is as follows: Step A: Under nitrogen protection, 15 parts of maleic rosin acid, 20 parts of epichlorohydrin and 0.04 parts of benzyltriethylammonium chloride are mixed evenly and reacted at 110°C for 4 hours. The temperature is then lowered to 75°C, and 8 parts of maleic anhydride and 0.02 parts of p-hydroxyanisole are added and mixed evenly. The mixture is reacted for 3 hours to obtain modified rosin. Step B: Mix 15 parts of modified rosin, 25 parts of 1-thioglycerol and 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone evenly, and irradiate with ultraviolet light at a wavelength of 380 nm for 40 min and an intensity of 30 mW / cm2 to obtain a tackifying resin.

[0031] Comparative Example 3: Comparative Example 3 is based on Example 2, except that 1-thioglycerol is not introduced in Comparative Example 3, and the remaining process steps and reaction parameters are the same as in Example 2; The preparation method of the tackifying resin is as follows: Step A: Under nitrogen protection, 15 parts of maleic rosin acid, 20 parts of epichlorohydrin and 0.04 parts of benzyltriethylammonium chloride are mixed evenly and reacted at 110°C for 4 hours. The temperature is then lowered to 75°C, and 8 parts of maleic anhydride and 0.02 parts of p-hydroxyanisole are added and mixed evenly. The mixture is reacted for 3 hours to obtain modified rosin. Step B: Mix 15 parts of modified rosin and 300 parts of toluene evenly, add 3 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.4 parts of N-hydroxysuccinimide, react for 0.8 h, then add 45 parts of amino-terminated maleimide, and react at 55 °C for 6 h to obtain the tackifying resin.

[0032] Experiment: Matte hot melt adhesives obtained in Examples 1-3 and Comparative Examples 1-3 were used to prepare samples. Their properties were tested and the test results were recorded. Tensile strength: Tested according to GB / T 1040.1-2025 standard using a computer-controlled electronic universal testing machine at a tensile rate of 100 mm / min. Each sample was tested three times, and the average value was taken. Shear strength: Tested according to GB / T 7124-2008 standard using a computer-controlled electronic universal testing machine. The adhesive substrates used were PC and PC. The tensile rate was 5 mm / min. Each sample was tested three times, and the average value was taken. Heat resistance: The heat resistance of the hot melt adhesive was tested according to GB / T 7124-2008 standard. The adhesive substrates used were PC and PC. After curing the samples at 25℃ / 50%RH for 7 days, they were placed in a 120℃ oven and left to stand for 24 hours. The tensile and shear strengths were tested using a 120℃ high and low temperature tensile testing machine to evaluate its heat resistance.

[0033] The test results are shown in Table 1.

[0034] Table 1. Test results of relevant performance of matte hot melt adhesives Based on the data in the table above, the following conclusions can be clearly drawn: Based on Examples 1-3 and Comparative Examples 1-3, it can be seen that the matte hot melt adhesive prepared by the present invention has excellent mechanical properties and heat resistance, and also has a good matte finish.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding, characterized in that: Includes the following steps: Step S1: Dehydrate polyester polyol, polyether polyol and tackifying resin under vacuum at 110-130℃ for 2-3 hours, cool down to 60-70℃, add diphenylmethane diisocyanate and dibutyltin dilaurate under nitrogen protection, react at 100-130℃ for 2-4 hours, cool the system temperature to 90-95℃, add hydroxyl-terminated polydimethylsiloxane, continue the reaction for 1-2 hours, and then perform vacuum degassing until no bubbles appear to obtain polyurethane hot melt adhesive; Step S2: Mix polyurethane hot melt adhesive, polystyrene resin, matte agent, filler and antioxidant evenly, melt-blend and extrude, granulate, and dry to obtain matte hot melt adhesive.

2. The method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 1, characterized in that: The polyurethane hot melt adhesive comprises the following components by weight: 20-40 parts polyester polyol, 30-50 parts polyether polyol, 10-20 parts tackifying resin, 60-80 parts diphenylmethane diisocyanate, 0.5-1.5 parts dibutyltin dilaurate, and 3-8 parts hydroxyl-terminated polydimethylsiloxane.

3. The method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 2, characterized in that: The preparation method of the tackifying resin is as follows: Step A: Under nitrogen protection, maleic rosin acid, epichlorohydrin and benzyltriethylammonium chloride are mixed evenly and reacted at 105-115℃ for 3-5 hours. The temperature is then lowered to 70-80℃, maleic anhydride and p-hydroxyanisole are added and mixed evenly. The mixture is reacted for 2-4 hours to obtain modified rosin. Step B: Mix the modified rosin and toluene evenly, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, react for 0.5-1.0 h, then add amino-terminated maleimide, and react at 50-60℃ for 5-7 h to obtain a compound containing double bonds. Step C: Mix the double bond compound, 1-thioglycerol and photoinitiator evenly, and then irradiate with ultraviolet light to obtain the tackifying resin.

4. The method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 3, characterized in that: In step A, the modified rosin comprises the following components by weight: 10-20 parts of maleic astringent, 15-25 parts of epichlorohydrin, 0.03-0.05 parts of benzyltriethylammonium chloride, 5-10 parts of maleic anhydride, and 0.01-0.03 parts of p-hydroxyanisole.

5. The method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 3, characterized in that: In step B, the mass ratio of the modified rosin, toluene, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide and amino-terminated maleimide is 1:(15-25):(0.1-0.3):(0.08-0.10):(2-4).

6. The method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 5, characterized in that: The preparation method of the amino-terminated maleimide is as follows: Under nitrogen protection, maleic anhydride and N,N'-dimethylformamide were mixed evenly, heated to 60-70℃, and a mixed solution of 2-(4-aminophenyl)-5-aminobenzimidazole and N,N'-dimethylformamide was added dropwise over 0.5-1.0 h. The reaction was allowed to proceed for 2-4 h, and the mixture was cooled to room temperature. After filtration, washing, and drying, an intermediate was obtained. Under nitrogen protection, the intermediate was mixed evenly with xylene, and p-toluenesulfonic acid and p-hydroxyanisole were added. The mixture was then refluxed at 100-110℃ for 5-7 h to separate water and cyclize and dehydrate. After rotary evaporation, filtration, washing, recrystallization, and drying, amino-terminated maleimide was obtained.

7. The method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 3, characterized in that: In step C, the tackifying resin comprises the following components by weight: 10-20 parts of a compound containing double bonds, 15-30 parts of 1-thioglycerol, and 1-3 parts of a photoinitiator.

8. The method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 1, characterized in that: The matte hot melt adhesive comprises the following components by weight: 80-90 parts of polyurethane hot melt adhesive, 10-20 parts of polystyrene resin, 20-40 parts of matting agent, 2-5 parts of filler, and 1-3 parts of antioxidant.

9. A method for preparing a matte hot melt adhesive for high-temperature hot pressing bonding according to claim 8, characterized in that: The matte agent is a mixture of EPDM rubber, nitrile rubber and SEBS in a mass ratio of 1:(3-5):(4-7).

10. A matte hot melt adhesive for high-temperature hot pressing bonding prepared by the preparation method according to any one of claims 1-9.

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